a ome , il how rar f 4 » ty =e OR ty ies a. ~. y, , aay ‘ \) a “4 a. ey < « ; ws y iA. Ph ie Na wr 9. 1 a ‘7 aera Rnaaeagires sol nei ‘ a. AO ‘ Rivne ¢ 2943 Hibrary of the Museum OF COMPARATIVE ZOOLOGY, AT HARVARD COLLEGE, CAMBRIDGE, MASS. Hak The gift of . gana eee A b Sue mr Le Np No. S¥IL ie Am ef ae / TRANSACTIONS OF THE NEW YORK ACADEMY OF SCIENCES. A ge P = +> ST a NER, ace 7 22, 24 & 26 F Aes NEW Y READE or new yoRK. TRANSACTIONS OF THE New York AcabEMY OF SCIENCES LATE LYCEUM OF NATURAL HISTORY. VEO UR MG Ee Val October, 1886, to August, 1887. “NEW YORK: PUB RESHED BY THE ACADEMY. OFFICERS OF THE ACADEMY. 1887. President. JOHN S. NEWBERRY, - - - = - Columbia College. Mice-Lresidento. OLIVER P, HUBBARD, - W. P. TROWBRIDGE. Corresponding Secretary. ALEXIS A, JULIEN, - - - - Columbia College. Mecording Secretary. HERMAN L. FAIRCHILD, - - 102 East 52d Street. ‘Gzeasurer. HENRY DUDLEY, - - - - 301 East 17th Street. Libsarian. N. L. Britton, - - - - Columbia College. Council. J. A. ALLEN, P. H. DUDLEY, A. R. LEEDS, D. S. MARTIN, J. J. STEVENSON, C. VAN BRUNT. Cuzators. B. B. CHAMBERLIN, F. J. H. MERRILL, S. LOWELL ELLIOT, CHARLES E. PELLEW, GEORGE F. KUNZ. Finance Committee. L. E. CHITTENDEN, JOHN H. HINTON, WILLIAM H. RUDKIN. Sditor of Qunabs. Sditor of Bransactions. DANIEL S. MARTIN. HERMAN LEROY FAIRCHILD. TABLE QE: CONTENTS. VOLUME VI, BUSINESS PROCEEDINGS. PAGE PP econ EO tHEe EWEAEY ooo oS sce sine cbs ne. wn sases 20% 109, 185, 188 PEE, Ole CMIDCIS soa) 5-25) os, = «7d, meprsielese vance’ Seles a 36, 58, 129, 136, 163 BHCC IGT OMONTHCCTS pick elo & oie Sie hele voice vole ole winwtale bs Datek le 8 as bathiacel 110 MEH Era lMINOWCESHM cette cee eee oe ce cen bak dae old otece te See 11, 41, 65 Reports: OHIMALEBCED ta ois ey te >) elamiais clerae As etree ers 6 oSicie wis bow. 58, 66, 136 Otte SPOHOIR SCOT OUANY Ua cic. asic Spe sap hs< 2s qalcs'arees wquie si 160 WouneI se oe cine ae 1, 36, 58, 66, 91, 112, 113, 128, 129, 136, 160, 163 ESOC OTOIH Py SCCLOLALV ccc aera eo, caies aisiaiwe nao sieciet sic iiewaemes, vale 109 WibPrarinns.. 3/5. BOS Wels oo Bee Re ie caite setae) ba ates oe aR 109, 167 PG AR TT Clon ere foyer cies or niccora ele efedeial cites, oo ioe Wier oneta aie o Sie nels noes es 110 Minutes of Meetings: Business Meetings ........... 1, 35, 58, 65, 91, 108, 112, 128, 136, 160 Special) Meetings: a4.).iew cies Ne wits 5 o ote wislntec le sans Geo esses 162 Stated Meetings, 12, 18, 35, 39, 40, 41, 65, 70, 77, 92, 93, 118, 121, 122, 129, 185, 138, 146, 147 CANE CHING ESV led Weer a) cis) «151) SFenie vic o0,.niese%als iio. ate e leew eiee'e sa capers 1, 2, 58 SCIENTIFIC PROCEEDINGS. 2 UPL TIL SET ORS eA al ep Aamo Se Par nes gies a a Se 60-65, 93 EMME = iste aiaw sie va ele ay diciaftsic us sae Wseank oe ecacee net ate 93-108, 134 ABU alent Po oie os fle oa ataiiam ines of So 0'el Dine win’ he's w/a 40 UTE oc oe RR ee oe ener 66-70, 112 pee: i Ay ttt he Abies alah otg x's asi Civics aid a)5 soe ane 9-11, 135 gE OTE gee ole el eiaic iatcinn wa tales aeamsle ed ws 6a00es = 5 0Sn0 tice 111 JB art pay nk Si ee aa ae ee 60-65, 77, 129, 188, 147, 165 Geology and Paleontology, 12-18, 35, 41, 59, 113, 122, 124-128, 137, 138, 164, 165 vil TABLE OF’ CONTENTS. PAGE Elistory of the ACAUSMY < ce ae sete we hun Gwin ea sew vcs sc 2 +e nls clara 146, 147 ELV SIOTISS sc24u store yore Vere ctcvenaetartorer ein ele rotate a eriass orev elei slelere steievol eke 42-58, 114-121 Mechanics and Engineering, 42-58, 65, 77-91, 114-121, 122, 131-134, 148-160 Meteorolory oi...) Secs ois ses 35, 40, 70, 71-76, 92, 141-146, 160-162, 166 Mineralogy, 2-11, 12-16, 39, 40, 41, 70, 71, 77, 91, 92, 111, 112, 118, 122, 129, 180, 135, 189-141, 165, 166 Photography... 28.4. Ko sich See. sedi os dsts he re eee ene ee ee eee 42 PHYSIOLOGY re tere. ners ers'oic a wieretetenePar dope eis, Sas ate evsi’ elstot ie aierenmreeeere 1138, 114-121 SOISMOLORY sic iG Gistectso swiele payee oi a eats eyearaa eee 18-35, 65, 91 POOLO REY: ai ayers to sins Od UIC eee Os le in wits Sas Saal 70, 77, 111, 5118, 185,139 GIS trOP EXCHANGES c. seycccle cic 6a ies Sisis \ 5's, see Cee cee 167 PAPERS READ BEFORE THE ACADEMY. A. P. BJERREGAARD. Report upon the Pink Dolomite recently obtained near Morrisania, with analysis (February 7, 1887), without abstract.............. 91 CHARLES H. BOLLMAN, Monograph of the North American Iulidz (February 28, 1887), read OY LEM CAT ross stars wisis terete avers ities excnie eeoinis Sees OS eI See ee 111 N. L. BRITTON. Additional Notes on the Geology of Staten Island (Ootober 11, NSE) sin: cceter a sieuaeisyp raid ayeiens olacare soared icieiainl aie. vis cic hcan One ee 12 Note on the growth of a Vinegar Plant in fermented Grape Juice (J AMMUATY WOM SST). Meters a stcisiereus etoul verter stetetcie sie o.0 sic = ov een ee 66 L. E. CHITTENDEN, Observations upon Earthquakes (November 1, 1886)................ 36 The Use of Metals by the Aborigines of Georgia and Florida (De- Ceniber'G: ViSS6) irre. ote sels cinta sete omarion ELMER L. CORTHELL. The Isthmian Ship Railway (December 20, 1886), without abstract. 65 HENRY DRUMMOND. The Heart of Africa (August 15, 1887), without abstract............ 165 TABLE OF CONTENTS. Vii PAGE CARL H. EIGENMANN and JENNIE E. HORNENG. A Review of the Chetodontide of North America (January 31, TART, eae OY Title. .055 265, os oress atsleteds PASS Sete teteisvers Ce patetsinee: He HERMAN LEROY FAIRCHILD. Transformations of the Skin in the Animal Kingdom (March 7, A APTEIECILE ROSETINCE. 4 «ao a cixiai =a os siela'els eins s = xe © BA wi ei< Wi aje’s © 113 J. J. FRIEDRICH. Notes on Local Mineralogy (April 11, 1887)..... aiitotetohie areletahei witelete wd 130 WILLIAM E. HIDDEN. A Notable Discovery of Precious Stones in Alexander Co., N. C. KOLO DEAR ASG) erettcenictois aislajer= wisistyeicvelaiecicie's) \s\ cue =ie1n oo. slate sinieis) 9) 2 On an Iron Meteorite that fell at Mezatpil, Mexico, during the Dis- play of ‘‘ Bielid ” Meteors, November 27, 1885, with an Account of its Fall, by Prof. José A. y Bonilla, Director of the Zacatecas Mbiouvatocy (January 11, LOOT) cs... neces ca cen ss acc seu neds sues 71 ALEXIS A. JULIEN. The Transformations of Iron Disulphide (April 18, 1887) ........... 135 GEORGE F. KUNZ. On the New Artificial Rubies (October 4, 1886)..... ....... ....05- ay Meteoric Iron from Carroll Co., Kentucky (January 17, 1887) ...... 71 A New Meteor from Catorze, Mexico (January 17, 1887), abstract.. 76 Hydrophane (Magic Stone) from Colorado (February 28, 1887)...... a fila! Crystals of Hollow Quartz from Arizona (March 28, 1887) ......... 122 Oniade and sageine (Nay i9) TSB ie 5 tna .5 nix ome ou se me sini spm erica wi) oe 139 Description of the Meteorite which fell near Cabin Creek, Johnson Co., Arkansas, March 27th, 1886 (May 9, 1887)................. 141 A Meteorite from Powder Mill Creek, Tennessee (June 6, 1887), ab- AMI detects ate tad Posiaeivicw oe cae tikei ales eiaesimerd sos, at's 161 Jasperized and Agatized Woods from Arizona (August 15, 1887).... 165 GEORGE N. LAWRENCE. Description of a New Species of Thrush (Margarops albiventris) from the Island of Grenada, W. I. (February 28, 1887), read by Descriptions of New Species of Birds of the Families Sylviide, Tro- glodytidz, and Tyrannidz (May 9, 1887), read by title .... .... 139 Vili TABLE OF CONTENTS. PAGE ALBERT R. LEEDS. The American System of Purification of the Water Supplies of Cities (November: 29501886) 5 ci 1a0 icici sis 'clee olaieeteleisie «lee eietoleiets 42: DANIEL S. MARTIN. A Monument to J. J. Audubon (August 15, 1887)............ siafeteleiete 163. F, J. H. MERRILL. Notes on the Geology of Block Island and Nantucket (October 25, 1SSG) ee oes leis s eprels ciew a'eie ctatele , Mince 6,c0einks, 2, cieetere pate its — ieee eres 30 Note on the Green Pond Mountain Group of New Jersey (December Gi UISBG) ete eterete 5c. <0 os aig Sew Sete aeio alee ce ou Wteie 9/> ale attiwlal eee 59 HENRY A. MOTT. A Limit to the Height of the 5 eee i (November 8, 1886), with- GULAIOSUTGEE 32h 3% Solas cists hm nis etal tale Wale) Mavala ares wisis ? aieje a altie atoll 40 JOHN S. NEWBERRY. Earthquakes, What is Known and Believed about them by Geolo- Pints (October aS, 18e0) a eeakie 4 do Mase neal ele «oe eee 18 The Fauna and Flora of the Trias of New Jersey and the Connecti- cut Valley (March 28, 1887), abstract.........0+-seecsscccvcces 124 Ccelosteus, a New Genus of Fishes from the Lower Carboniferous Limestone of Illinois (May 2, 1887), abstract................06- 137 A New Meteorite from Tennessee (June 6, 1887), abstract........... 160 Description of a New Species of Titanichthys (August 15, 1887), ab- SEP GCE sco ee esas «5 re ein ers ara ee nletaye tales etaeiel esehote leer oe ela eteteeatetene .. 164 CHARLES E, PELLEW, Recent Investigations on the Mitigation of Pathogenic Bacteria (November 15, 1886), without abstract... .....ssseseeeree cocce 40 HENRY H. RUSBY. Notes of Recent Travel on a Journey from La Paz to Para, through the Bolivian Andes and the Valleys of the Beni and Madeira Rivers (April 4, 1887), without abstract... ......eceeeeeeecees 129 Further Notes of a Scientific Journey across South America, through the valleys of the Beni and Madeira Rivers (May 2, 1887), with- OUE GOSER GEE Feo. store mS eles ers ero a ae chasis Sis Gs sininiean = a 138 Concluding Observations in a Scientific Journey across South America, from the Andes to the Mouth of the Amazon (May 16, 1887), t0tGhOWl QOSUROC Gee's ele weiss opie we sua, ocia'n nce ieh NiaieWie er nieiale 147 TABLE OF CONTENTS. 1x PAGE JOHN J. STEVENSON. Notes on the Surface Geology of 8S. W. Virginia (March 7, ee PUR TR TERME Reese ahs 7a si asc crea wins sa ones ease ce ese ed Te oi praraere) alc WILLIAM E. TROWBRIDGE, On Sub-surface Water-supply for Cities and Towns (January 31, EMRE ssat tarsi ains/oieiat Ah S canazn Sree misao eine 4 ereiatete ta ciate) wale /aia nw 6 oinvatwa 77 Laws of Fatigue and Rest in Animal Mechanics as Applied to Boat Raeines (Marche 145 1 S87))ierccisae eric srecite s sieinletetsts slew iers.c\ccsie,es cyereiere 114 A. W. VOGDES. The Genera and Species of North American Carboniferous Tri- lobites (March 38; 1887); read by Title ise 62.8.2. dette seh rine cede 122 CHARLES B. WARRING. On Certain Laws of Gyrating Bodies (April 11, 1887)............... 131 JOHN S. WHITE. The Landskibet, or Viking Skip, Discovered near Gokstad, Norway, in 1880 (February 14, 1887), without abstract............ sisierelersre 93 LECTURES OF THE POPULAR LECTURE COURSE OF 1886-1887. HENRY L. ABBOTT. Sea-Coast Defense (March 21, 1887), without abstract,.......2+++0+- 122 WILLIAM LIBBEY. Recent Explorations in Alaska (January 24, 1887), without abstract, 77 CHARLES S. MINOT. The Evolution of the Head (April 25, 1887), without abstract....... 135 JOHN K. REES. The Great Telescopes of the World; their Construction, Powers, gud) bamitations (February 21, 1887)...<0...0..00..ces0es secre 93 WILLIAM P, TROWBRIDGE. The Development of Bridge Construction, with Notices of some Re- markable Historic Bridges (May 23, 1887)...........ceeseeerees 148. eX: TABLE OF CONTENTS. LIST OF PLATES AND FIGURES. PAGE Wavities.in Artificial. Ruby (two cuts).. oi... vx <.s< oc hte semen meee 5 Liquid-Cavities in Natural Ruby and Sapphire.... ... .........-. 5 Acicular' Crystals in Sappaire 2. sch. fee wey | ae wn case sae tf Cuneiform Crystals in Ruby and Sapphire..........02 2.00: ce000s 7 National saber, ciciectscccm dclee.nc arerss. sue pea cce soe win. ose ores cs Cases facing 55 Wattonal sHilcer 5:2. a s1c\ode.ws Oey Se pee eeinte cue me's vince oa facing 56 Barring of Meteoricsirony <2. % cass «dailies sbisidsias\s «acer 72 Carroll County Meteorites .ij0.< 5,236.6 <5, sisi oS ais ass ss. mies ete 73 Sections of Carroll County Meteorite (8 cuts)........... ..ee0 eee 74 Section of Iron:from-the Turner Mounds, ....0 <2. i0..0. «- saveewene 74 Catorze Meteorite’ ...54.00c6.5 ec ne'sn esc ees acres sone s< 6 etereeeeane 75 Widmanstatten Figures in Catorze Meteorite..............6. ceeeee 76 BD) VST VVIOUISS ico wrara ais, caked neve io ayokererd Onis ieteen eiaisoreeataie ms ee eyo caters facing 82 Hollow Quartz Crystals. oi. 5 sista « caters «sens ) wayoais cals orale hie ete 123 TRANSACTIONS OF THE NEW YORK ACADEMY OF SCIENCES. October 4, 1886. REGULAR BusINESS MEETING. The President, Dr. J. S. NEWBERRY, in the chair. Forty-four persons present. The Report of the Council was received and adopted, recom- mending the acceptance of the resignation of Mr. George A. Plimpton, and the payment of certain bills. . The secretary presented a resolution proposing the following changes in the By-laws: I. To insert in Chapter IV. the following section, to be num- bered Section 5, and the other sections to be renumbered ac- cordingly: 5. The librarian shall have the immediate supervision and care of the library, under the general authority of the library committee of the council. All accessions to the library shall pass through his hands, and he shall enter the titles to the same in a suitable book kept for that purpose. He shall indelibly stamp every book, pamphlet, paper, or other matter, with the stamp of the society, as prescribed by the library committee or council. He shall periodically make a detailed report of acces- sions, and on the fourth Monday in February shall make an an- nual report on the condition of the library. II. In Chapter VIII., Section 1, to change the term “jive dol- 2 TRANSACTIONS OF THE [oct. 4, lars” to ‘‘ten dollars” wherever it designates the amount of fees or dues. III. To append to Section 4, Chapter VIII., the following: By a two-thirds vote of the members and fellows present at any regular business meeting of the society, provided that such ac- tion shall have been recommended by the council, and at least one month’s notice given in writing to the delinquent to show cause why such erasure should not be made. IV. In Chapter IX., Section 1, to change the word ‘ Pro- ceedings” to ‘* Transactions.” V. In Chapter XIV., to insert the following as ‘‘ Section 4: ” The rules of order as set forth in ‘* Cushing’s Manual of Parlia- mentary Proceedings,” shall be accepted as authoritative in the meetings of the society. VI. To insert as Section 2, in Chapter XVI., the following: Any member or fellow may be censured, suspended, or expelled for violation of the Constitution and By-laws, or for any other offense deemed sufficient, by a vote of three-fourths of the members and three-fourths of the fellows present at any regular business meeting, provided that such action shall have been recommended by the council at a regular business meeting, and one month’s notice of such recommendation and of the offense charged shall have been given the member accused. Mr. Witi1am E. HIDDEN read an informal paper on A NOTABLE DISCOVERY OF PRECIOUS STONES IN ALEXANDER COUNTY, oNe a0. On the 2d and 9th of last August, discoveries of emeralds and hiddenites were made at the mine of the Emerald and Hiddenite Mining Co., which are well worth noting before this Academy. Not since 1882 has such an important ‘‘ find” been made at this mine, and in several respects the last discovery exceeds all previous record of this mine’s output. Up to this year, the largest crystal found of the emerald-green spodumene, known in the gem-markets as hiddenite and lithia emerald, had only furnished a gem of two and five-eighths karats weight, valued at about $300; but the ‘‘ find ” of August 2d will yield gems of perhaps double this weight, of very beauti- ful color. One twin crystal (which is here exhibited) weighs one-half ounce in its rough state, and has been appraised at $900 valuation by a competent and well-known dealer in pre- cious stones. Several of the best crystals are more than one inch long, and are twinned like the last-mentioned crystal. In ail about ten ounces of good material was found, out of which twenty to thirty pieces will cut fine gems of high market value. 1886. | NEW YORK ACADEMY OF SCIENCES, 3 This ‘‘ find ” was made at a depth of only six feet, and at a place distant about five rods from the old original discovery site. As in previous cases, the associated minerals were quartz crystals, rutile, and mica (?), with a vein filling of lithomarge in which the gem crystals were imbedded. On August 9th, at a place yet nearer the shaft of this company, a discovery of emeralds was made which in themselves were the greatest encouragement that this locality (Alexander Co.) has ever given, as proving the existence in that region of fine emerald gems. A narrow ledge of outcropping opaque quartz was worked down upon to a depth of fifteen feet, where the quartz became clearer, and a ‘‘ pocket” began to show itself. Crystals of quartz and of muscovite (?) in profusion were found within the next foot of the vein, imbedded in lithomarge (kaolin- like clay of a light-brown color), all in rare perfection of form and material. In the next three feet of the vein (it was once an open pocket), imbedded in the lithomarge, I took out eight of the best crystals of emerald which the locality has furnished since 1882. In point of uniform color, and of crystallographic interest, the ‘‘ find” was peculiar to itself. The best emerald weighed eight and three-quarter ounces, was one and three- quarter inches thick, and three inches long. All the crystals of emerald were wholly or in part doubly terminated and of pure hexagonal forms, with a flat terminal plane. Two crystals had a very low pyramid occurring partly developed, which may be new to science when its angle is measured. Faces of the sec- ondary prism and of secondary pyramids were only present in traces. The crystals had a very uniform thickness, of about two-thirds their length, with end faces of superb polish. One crystal, the second in size, had implanted upon a prismatic face a crystal of rutile in perfectly parallel position (axially) to that of the emerald. ‘This is curious, for the reason that the two minerals are so diverse in composition and so dissimilar in form. Altogether, the eight crystals of emerald weighed twenty-one ounces. Shortly before these ‘‘ finds ” were made, a pocket, the sixth in regular succession of a vein of ‘‘ pockets,” was opened at a depth of forty-three feet in the old shaft, und among a handful of inferior emeralds one was found which yielded a fine-cut gem of four and five-eighths karats weight, which gem is very probably the finest cut emerald exhibited in the United States. The value, intrinsically, of these gem discoveries is not far from $5,000, which is a most tangible encouragement for future work. Of interest, perhaps, is the fact that for the past four years all the work done at this mine has been a source of profit to the Emerald and Hiddenite Mining Company, and thus with 4 TRANSACTIONS OF THE [ocr. 4, good reason we can feel proud of this new undertaking in min- ing exclusively for gems. Of interest to mineralogists, besides the beautiful emeralds and spodumenes, there were also found this past season, in the near vicinity of this mine, some few very remarkable crystals of highly modified quartz, with planes not before credited to the region. In the species rutile and monazite, new discoveries have been made of exceedingly beautiful crystals. It seems to me that we have in the Piedmont region of the Southern States the counterpart of the Ural mineral district in Russia and the Minas Geraes district of Brazil. All are foot-. hill areas of very similar features geologically. If the South seems to be behind these other regions just mentioned, it is probably due to the fact that the South presents a newer field to. the investigator than the others. Though this foot-hill region of the South is only thirty-six hours journey from New York, it receives less attention from mineralogists, geologists, and other scientists than localities thousands of miles distant. My own personal experiences in these southern regions during the past eight years have convinced me that nowhere have we more promising fields for the discoverer in any branch of science. Dr. T. Sterry Hunt spoke of the mineralogy of the local- ity referred to by Mr. Hidden, and discussed with him Prof. Kerr’s theory of ‘ frost-drift.” Mr. GeorGe F. Kunz read a paper ON THE NEW ARTIFICIAL RUBIES. (Illustrated with specimens and microscopical preparations. ) The subject of artificial gems is at the present moment of con- siderable interest, not only financially, but also as furnishing an example of the manner in which the microscope is constantly called into use by almost every profession. arly this summer,. the Syndicate des Diamants et Pierres Precieuses were informed that certain stones, which had been sold as rubies from a new locality, were suspected to be of artificial origin. They were put upon the market by a Geneva house ; and it was surmised that they were obtained by the fusion of large numbers of small rubies, worth at the most a few dollars a karat, into one fine gem worth from $1,000 to $2,500 a karat. Some of these artificial stones were kindly procured for me by Messrs. Tiffany & Co. I was not, however, permitted to break them for analysis, to observe the cleavage, or to have them cut so that I could observe the optical axes more correctly. I would at any time have detected the artificial nature of this production 1886. | NEW YORK ACADEMY OF SCIENCES. Sy) with a mere pocket lens, as the whole structure is that peculiar to fused masses. Examination elicited the following facts : The principal distinguishing characteristic between these and the genuine stones is the presence in them of large numbers of spherical bubbles, rarely pear-shaped, sometimes containing stringy portions showing how the bubbles had moved. ‘These Fic. 1.—Spherical cavities in artificial Fig. 2.—Spherical and irregular cavities ruby as seen at one time (en- in artificial ruby as seen at one larged 75 diameters). time, evidently from the lower part of the crucible (enlarged 25 diameters). bubbles all have rounded ends, and present the same appearance as those seen in glass or other fused mixtures. ‘l'hey are nearly always in wavy groups or cloudy masses. When examined indi- vidually they always seem to be filled with gas or air, and often form part of a cloud, the rest having the waviness of a fused mixture. Some few were observed inclosing inner bubbles, apparently a double cavity, but empty. In natural rubies, the cavities are always angular or crystalline in outline, and are usually filled with some liquid, or, if they form part of a ‘< feather ” as it is called by the jewelers, they are often arranged with the lines of growth. Hence the difference in appearance 1@®s ff Fic. 3.—Liquid cavities in natural ruby and sapphire (enlarged 100 diameter.) f 9 c) between the cavities in the natural gem and those in the fused gem is very great, and can readily be detected by the pocket lens. I have failed to find in any of the artificial stones even a trace of anything like a crystalline or angular cavity. Another distinguishing characteristic is that in many genuine rubies we find a silky structure (called ‘‘silk” by the jewelers), which, if examined under the microscope, or under a +4 to 38; Inch objec- tive, we find to be a series of cuneiform or acicular crystals, often iridescent, and arranged parallel with the hexagonal layers of the crystal. When in sufficient number, these acicular and 6 TRANSACTIONS OF THE [ooT. 4, arrow-shaped crystals produce the asteria or star effect, if the gem is cut in en cabochon form with the center of the hexagonal prism on the top of the cabochon. I have failed to find any of them in the stones under consideration, or even any of the marking of the hexagonal crystal which can often be seen when a gem is held in a good light, and the light allowed to strike obliquely across the hexagonal prism. Dr. Isaac Lea has sug- gested’ that these acicular crystals are rutile, and interesting facts and illustrations have been published by him. From my own observations on many specimens, I believe there is little doubt of the truth of this hypothesis.* My explanation is, that they were deposited from a solution, either heated or cold, while the corundum was crystallizing, and I doubt very much whether they will ever be found in any substance formed by fusion. The hardness of these stones I found to be about the same as that of the true ruby, 8.8, or a little less than 9, the only differ- ence being that the artificial stones were a trifle more brittle. The testing point used was a Siamese green sapphire, and the scratch made by it was a little broader but no deeper than on a true ruby, as is usually the case with a brittle material. After several trials I faintly scratched it with achrysoberyl, which will also slightly mark the true ruby. The specific gravity of these stones I found to be 3.93 and 3.95. The true ruby ranging from 3.98 to 4.01, it will be seen that the difference is very slight, and due doubtless to the pres- ence of the included bubbles in the artificial stones, which would slightly decrease the density. Asa test, this is too deli- cate for jewelers’ use ; for if a true ruby were not entirely clean or a few of the bubbles that sometimes settle on gems in taking specific gravities were allowed to remain undisturbed, it would have about the same specific gravity as one of these artificial stones. I found, on examination by the dichroscope, that the ordinary image was cardinal red, and the extraordinary image a salmon red, as in the true ruby of the same color. Under the polari- scope, what I believe to be annular rings were observed. With the spectroscope, the red ruby line, somewhat similar to that in the true gem, is distinguishable, although perhaps a little nearer the dark end of the spectrum. The color of all the stones examined was good, but not one was as brilliant as a very fine ruby. The cabochons were all duller than fine, true stones, though better than poor ones. They did not differ much in color, however, and were evidently 1 Proc. Philad. Acad. Sc., Feb. 16, 1869, and May, 1876. * Paper on star garnets, N. Y. Acad. Sc., May, 1886. 1886. | NEW YORK ACADEMY OF SCIENCES. 7 made by one exact process or at one time. Their dull appear- ance is evidently Jue in part to the bubbles. The optical prop- erties of these stones are such that they are evidently individual or parts of individual crystals, and not agglomerations of crys- tals or groups fused by heating. In my opinion, these ar tificial rubies were produced by a pro- cess similar to that described by Fremy and Feil (Comptes Rendus, 1877, p. 1029), by fusing an aluminate of lead in connection with silica in a siliceous crucible, the silica uniting with the lead to form a lead glass, and liberating the alumina, which crystal- lizes out in the form of corundum in hexagonal plates, with a specitic gravity of 4.0 to 4.1, and the hardness and color of the natural ruby, the latter being produced by the addition of some chromium salt. By this method rubies were formed that, like the true gem, were decolorized temporarily by heating. It is not probable that these stones were formed by Gaudin’s method (Comptes Rendus, xix., p. 1342), by exposing amorphous alumina to the flame of the oxyhydrogen blowpipe, and thus Fic. 4.—Acicular crystals in sapphire Fic. 5.—Cuneiform crystals in ruby and (enlarged 100 diameters), sapphire (enlarged 200 diameters). fusing it to a limpid fluid, which, when cooled, had the hardness of corundum, but only the specific gravity 3. 45, much below that of these stones. Nor is it at all likely that they were produced by fusing a large number of natural rubies or corundum of small size, because by this process the specific gravity is lowered to that of Gaudin’s product. The same also holds good of quartz, beryl, ete. The French syndicate referred the matter to M. Friedel, of the Ecole des Mines, Paris, supplving him with samples of the stones for examination. He reported the presence of the round and pear-shaped bubbles, and determined the hardness and specific gravity to be about the same as in the true ruby. On analysis, he found them to consist of alumina, with a trace of chromium for the coloring matter. ‘The cleavage was not in all cases dis- tinct, and the rough pieces given to him as examples of the gem in its native state had all been worked, so that nothing could be learned of their crystalline structure. When properly cut according to axes, they showed the annular rings. The extinc- 8 TRANSACTIONS OF THE [ocor. 4, tion by parallel light was not always perfect, which he believed to be due to the presence of the bubbles. He states that he himself has obtained small red globules with these inclusions by fusing alumina by oxyhydrogen flame; and, although having no positive evidence, he believes these stones to be artificially ob- tained by fusion. On the receipt of M. Friedel’s report, the syndicate decided that all cabochon or cut stones of this kind shall be sold as artificial, and not precious gems. Unless consignments are so marked the sales will be considered fraudulent, and the mis- demeanor punishable under the penal code. All sales effected thus far, amounting to some 600,009 or 800,000 frances, shall be cancelled, and the money and stones returned to their respective owners. The action taken by the syndicate has fully settled the posi- tion which this production will hold among gem dealers, and there is little reason to fear that the true ruby will ever lose the place it has occupied for so many centuries. These stones show the triumph of modern science in chemistry, it is true; and although some may be willing to have the easily attainable, there are others who will almost want, what the true ruby is becoming to-day, the unattainable. One will be nature’s gem, and the other the gem made by man. The’ following recapitulation of the progress made from time to time by the different investigators in the artificial reproduc- tion of ruby and sapphire, may be of more than passing interest at this moment: Gaudin (OC. R., 1857, Vol. IV., p. 999, and 1857, Vol. XLIV., p. 716.—L’Inst., t. XXV., p. 110—J. pr. Chem., LXX., p. 381—Bibl. univ. de Genéve, t. XX XIV., p. 68. —Jahrb. f. Min., 1857, p. 444) was the first to reproduce corun- dum, which he did by heating before the oxyhydrogen blowpipe a closed crucible containing equal parts of alum and sulphate of potash and charcoal. It was tired for fifteen minutes and then slowly cooled. The mass was then lixiviated and attacked with diluted aqua regia, which left a sand formed of small corundum crystals, 1 mm. Jong and 4 mm. thick. They were hexagonal plates having bases striated in three directions parallel to the sides. Some very fine included microliths resembling sillimanite were also observed in these crystals. Elsner (J. pr. Chem., t. XVII., p. 175), operating in the same way, by fusing before the oxyhydrogen blowpipe anhydrous alumina with bichromate of potash obtained red crystalline grains as hard as rubies. 1 See ‘‘ Encyclopedie Chimique,” Tome II., Reproduction Artificielle des Mineraux, par M. L. Bourgeois. 1886. | NEW YORK ACADEMY OF SCIENCES. 9 De Sénarmont (C. R., 1851, t. XX XIT., p. 762.—L’Inst., 1851, . 165.—Ann. Chem. Pharm., t. LXXX., p. 214.—Pharm. ‘Centr., 1851, p. 518) has applied the wet way to the crystalliza- tion of alumina. He heated in a sealed tube, at 350° C., asolu- tion of chloride of aluminum, or of nitrate of alumina, and produced rhombohedrons with truncated edges. Almost at the same time Ebelmann obtained corundum (Ann. de Phys. et de Chim., 1851, t. XX XIII., p. 34) by a totally differ- ent process. He heated in a porcelain kiln a platinum crucible containing one part of amorphous alumina with three or four parts of borax. After a few days of heating all the borax was volatilized, and at the bottom of the crucible crystals of corun- dum were found, and on the edges long bluish needles of borate of alumina, which he separated by the action of chlorohydric acid. The corundum thus obtained was in hexagonal plates like specular iron of volcanic origin, and was quite similar to that obtained by Gaudin. The base is striated by three systems of lines parallel to the sides. Numbers of very irregular vitreous inclusions were noticed in them, as well as microliths resembling sillimanite. The density of the crystals was 3.98, and, like the natural stone, they scratched topaz; they have, as in natural specimens, sit p.? = 122° 35". Carbonate of baryta added to the mixture facilitates the formation of the crystals and the development of rhombohedral faces, which thus attain a length of several mm. Carbonate of lime may be added or the borax wholly replaced by carbonate of soda, but hexagonal or dodecahedral plates will still be obtained. Ebelmann colored his product by small quantities of metallic oxides. For example, violet was obtained by oxide of manganese (Oriental amethysts). It was noted that boracic acid alone could not replace the borax. Sainte-Claire Deville and Caron (C. R., 1858, t. XLVI., p. 764.—L’Inst., 1858, p. 133.—Ann. Chem. Pharm.,t. CVIIL., p. 55.—Dingl. pol. J., t. CXLVIIL., p. 372.— J. pr. Chem., t. LXXIV., p. 157) obtained magnificent specimens of corundum by a different method. They placed anhydrous fluoride of aluminum (Al, F,) at the bottom of a charcoal cruci- ble, and suspended in the centre of thisa cnpel of the same substance filled with boracic acid. The whole apparatus was allowed to remain at white heat for an hour, and on opening the crucible they found the interior lined with large thin hexagonal plates of corundum, presenting the combination a’ pe’. There were no striz on the bases, but only hexagonal rosettes project- ing, and brown arborescences. Vitreous inclusions of boracic acil with bubbles of gas were observed, often arranged in crowns, and fine microliths were also noticed, as already men- 10 TRANSACTIONS OF THE [oor. 4, tioned. They found that by adding a little fluoride of chrom- ium to that of aluminum, and using a clay crucible with cupels of platinum, they could produce rubies together with a little sapphire. When they increased the quantity of fluoride of chromium they obtained green crystals (Oriental emeralds). Debray (C. R., 1861, t. LIT., p. 985.—L’'Inst., 1861, p. 165.— Ann. Chem. Pharm., t. CX X., p. 184.—-Jahrb. f. Min., 1861, p. 702.—Bull. Soc. Chim., 1865) describes several methods of ob- taining corundum. He passed a slow current of chlorohydric acid over aluminate of soda at a red heat or over a mixture of phosphate of alumina and lime. In the latter case calcic wag- nerite was also produced. M. Debray has also produced crystals of alumina by melting phosphate of alumina with three or four times its weight of sulphate of potash or soda, and thus produc- ing an alkaline phosphate. Quite recently H. Grandean (C. R., 1882, t. XCV., p. 921) has had occasion to apply the preceding method to various oxides, and has found that particularly with alumina, after several hours of heating, a crystallized double phosphate of alumina and potash is obtained at the same time as the corundum. The mineral- producing qualities of fluohydric acid have been well employed by M. Hautefeuille in reference to alumina. It was only necessary to make the vapor of this acid (Ann. Chim. Phys.. 1865, t. IV., p. 153.—-Jahresb., 1814, p. 206) pass slowly over the amorphous alumina heated to a bright red heat in a platinum tube, previously diluting it with nitrogen and steam. On the hottest part of the tube foliated hexagonal plates of corundum will form, resembling very much specular iron of vol- canic origin. The more the operation is prolonged the more beautiful these become, for the smaller crystals are destroyed to make way for larger ones. M. Gaudin (C. R., 1869, t. LXIX., p. 1342), in 1869, gave a second method of producing corundum by exposing amorphous alumina to the flames of the oxyhydrogen blowpipe. This oxide melts into a very clear, fluid glass, which in cooling hardens into a crystalline globule as hard as corundum. MM. Fremy and Feil (C. R., 1877, t. LX XXV., p. 1029) have produced specimens of corundum remarkable for the size of the individual crystals and the weight of the crystalline masses, by means of a double decomposition in a dry way. They melted at a bright red heat in a large crucible of very siliceous material equal weights of alumina and minium, producing thereby a fusible aluminate of lead, which is soon destroyed by the silica. of the crucible, giving place to a still more fusible silicate and liberating the alumina, which crystallizes in the body of the liquid. Part of the lead is also volatilized or reduced by the gas 1886. | NEW YORK ACADEMY OF SCIENCES. 11 of the furnace. Breaking the crucible, they found a superficial vitreous layer of silicate of Jead, and underneath a mass of co- rundum erystals grouped in magnificent geodes. By the addi- tion of a little bichromate of potash rubies were obtained, and sapphires by the further addition of a little oxide of cobalt. These are the most beautiful crystals of ruby and sapphire that have ever been obtained, but their hexagonal tabular form unfits them for cutting. They have the properties of corundum; D=4.0 to 4.1. The rubies, like natural stones, were tempora- rily decolorized by heating. MM. Fremy and Feil have also added fluoride of barium to the aluminate of lead in the preced- ing experiment. The two reagents were mixed in equal parts with the addition of a little bichromate of potash, and heated in a siliceous crucible surmounted by another reversible crucible. In the lower crucible they obtained a geode of ruby with vitre- ous inclusions, while the upper one was lined with long needles of a silicate of alumina and baryta. According to the analysis of L. M. Ferreil, this product is probably a barium anorthite. MM. Fremy and Feil endeavored to retard the reactions in this experiment so as to increase the size of the crystals. M. Stanislas Meunier (C. R., 1880, t. XC., p. 701), decomposed in a red-hot tube chloride of aluminum by the use of steam. In several experiments magnesium or zine were also used as re- agents. Corundum was thus produced in hexagonal plates or crystalline grains. MM. Fouqué and Michael Levy accidentally observed the formation of corundum in beautiful hexagonal plates while they were fusing microcline feldspar with fluorite. The corundum by sublimation lined the platinum cover of the crucible in which the experiment was made. Last of all, M. F. Parmentier (C. R., 1882, t. XCIV., p. 1713), in a work relative to the action of molybdates upon oxides by dry process, has announced that the fusion of amorphous alu- mina with bimolybdate of potash will furnish corundum in plates like tridymite. It is important to keep the temperature of the crucible high, for if it is lowered an inverse reaction takes place. Dr. T. Sterry Hunt remarked upon the character of these artificial rubies, and upon the artificial production of minerals in general, and compared their properties with those of the nat- ural minerals. PRESIDENT NEWBERRY announced the death of Mrs. ERMIN- NrE A. SmitH, which occurred June 9, 1886. Prof. D. S. Martin, Mr. George F. Kunz, and Mr. B. B. Chamberlin were appointed a committee to prepare memorial resolutions. 12 TRANSACTIONS OF THE fooradds October 11, 1886. STATED MEETING. The President, Dr. J. S. NEWBERRY, in the chair. Thirty-six persons present. Mr. GeorceE F. Kunz exhibited artificial rubies from Paris, as supplementary to his paper read at the preceding meeting. PRESIDENT NEWBERRY Stated that the library of the Soviety had been removed, during the summer, under the authority delegated to the President and Secretary, from the American Museum of Natural History to the Herbarium room in the Li- brary Building of Columbia College. That the conditions under which the College received the library on deposit were, the con- tinued and absolute ownership of the library by the Academy, with the privilege of terminating the contract at any time ; and the College to bind and otherwise care for the library equally with its own. Dr. N. L. Britton read the announced paper, ADDITIONAL NOTES ON THE GEOLOGY OF STATEN ISLAND. On April 4th, 1881, I had the honor of presenting to the Academy the results of my studies on the Geology of Richmond County, New York. On December 12th, of the same year, I presented some additional notes on the same subject, and on November 24th, 1884, read a paper on the Glacial and Pre-Glacial Drifts of Staten Island. I now desire to bring forward other data, obtained by myself and associates since this last communication. No new outcrops of granite or gneiss have been discovered; those at Tompkinsville have, indeed, been partially covered by the embankment for the Rapid Transit Company’s railroad, and only a small ledge is now to be seen. It is to be noted that this coarse granite contains oligoclase feldspar in addition to its or- thoclase, and the probability is that the outcrop is the exposed top of a mass, perhaps a vein, similar to those of common oc- currence on New York Island and in Westchester County. In my communication of December 12th, 1831, allusion was made to an exposure of hornblende-rock on the shore of the Upper Bay at Brighton Point. This is an extremely tough, fibrous tremolite, hardly any other mineral being present in it. The outcrop showed no bedding planes; it is now wholly con- cealed by the made land around the railroad terminus at Saint 1886. | NEW YORK ACADEMY OF SCIENCES. 13: George. Therock is very similar to that from the bottom of the deep well at Bischoff’s Brewery. The serpentine and talcose rocks which form the ridge through the central part of the island have been re-examined with ec m siderable care. It will be remembered that in my first com-- munication I regarded these as metamorphosed magnesian limestones. In the course of the discussion which followed my second paper, Dr. Julien expressed his opinion, based on micro- scopical studies of the rock, which revealed the presence of much partially altered amphibole, that they are derived from hornblende schist, and the specimens from the deep well-boring above alluded to, being certainly partially hydrated and other- wise altered, gave support to his hypothesis. It now seems to me probable that both of these suppositions are in a measure correct: that the serpentines and associated rocks have been produced by the extensive alteration of both limestones and hornblendic, or rather tremolitic, strata, and that schists as well have furnished some of the material for their construction. This conclusion is now reached from the following considera- tions: 1. There is no proof whatever that these serpentines are -metamorphosed igneous rocks. We have failed to detect any olivine-like minerals in them; and in this respect they appear to. differ from the area near Baltimore recently described by Prof. Williams in Bulletin No. 28 of the United States Geological Survey. Messrs. Whitney and Wadsworth, in their discussion of azoic rocks in the Bulletin of the Museum of Comparative Zoology, Vol. VII., pp. 464-465, state that it seems more reasonable to them to ascribe an igneous origin to the rock in the region under consideration, because a large part of the thoroughly studied serpentines of the world have been proved to be the result of the metamorphism of igneous masses. It does not appear that these writers have ever visited the area, nor, indeed, that they have examined any of the rock. As it has been stated on good authority that the concluding portions of Messrs. Whitney and Wadsworth’s paper, dealing with a proposed classification of pre-Silurian rocks, were not meant to be taken as their actual ideas on the subject, but intended asa joke (though if this be so, it would have saved much unneces- sary thought and trouble had they designated it thus), and as the general tendency of their paper appears to be to criticise every investigator’s work without furnishing any more valuable suggestions than have been advanced, we must confess to some doubt as to Messrs. Whitney and Wadsworth’s actual position. 2. There is abundant evidence that these rocks are stratified, though this feature cannot be made out in every outcrop. The 14 TRANSACTIONS OF THE [ocr. 11, following observed dips and strikes from various portions of the area will indicate the truth of this statement : Near corner of Westervelt avenue and Second avenue, New Brighton, Str. N. 45 E., Dip 70 NW.; summit of the north- west side of Pavilion Hill, Str. N. 45 E., Dip 70-85 NW.; eastern side of Pavilion Hill, 900 feet west of the granite out- crops on the shore, Str. N. 45 E., Dip 70 NW. to nearly vertical; here the rock is delicately crumpled; west of Garretson’s Station, Str. N. 60 E., Dip 20-80 SE. and much contorted, ap- parently lying in several gentle folds ; west of Grant City, Str. N. 60 E., Dip 55-70 NW.; Ravine near Egbertville, Str. N. 75 E., Dip 85 SE.; on Meissner avenue, near Richmond, Str. N. 80 E., Dip. 80 N.; one-fourth mile northwest of this outcrop, strike and dip same; in valley of brook one mile north of Eg- bertville, Str. N.50 E., Dip. 40-50 NW. 3. All the serpentine areas of Southeastern New York and vi- cinity, such as those of Staten Island, Hoboken, West 59th street and vicinity, New York Island, New Rochelle and Rye, Westchester County, lie in the same general line of strike and appear to occupy a well-defined belt in the surreunding gneisses and schists. These outcrops may, indeed, be but portions of the same strata alternately buried by the pitch of the folds and again brought to the surface by faults of vertical throw; this structure has been conclusively demonstrated in the highlands of New Jersey, and may well apply to the rocks now under con- sideration. The crystalline limestone areas of New York Island and Westchester County lie parallel, cr nearly so, with this serpentine belt, as may be seen on the excellent map published by Professor Dana in the American Journal of Science, vol. XX. These limestone outcrops are of the same general shape as those of the serpentine and its associated minerals, and their detached occurrence is probably due to the pitch and fault structure above noted. Crystalline limestone occurs in and with the ser- pentines at the West 59th street area and at New Rochelle; at West 59th street, parts of the rock are indistinguishable from parts of the Staten Island material, and here is found in great abundance the ‘‘ hydrous anthophyllite,” which is very much like soine specimens from the deep well on Staten Island. Many of the crystalline limestones contain tremolite, and in some of them this mineral is extremely abundant ; specimens obtained by Mr. Kemp from near King’s Bridge are at least one-half tremolite. It is not alone in pure masses, butis scattered through the rock in fine crystals, and at Pleasantville, Westchester County, forms ‘mountain leather.” The serpentine of Staten Island contains much amianthus, doubtless the altered state of tremolite, and Mr. B. B. Chamberlin has found this matted into a substance 1886. ] NEW YORK ACADEMY OF SCIENCES. 15 similar to ‘‘ mountain leather” on Staten Island. The cleavage of the serpentine is much like that of the limestones, and on the cleavage faces of the latter there is often seen a development of tremolite, while on the serpentine faces there is considerable amianthus. The parallel metamorphism of schists in the production of these serpentines is indicated in the occurrence on Todt Hill, Staten Island, of a very soft, schistose rock, apparently now chloritic, containing altered crystals of tourmaline, a mineral quite abundant in the schists of New York Island. As regards the relative position of the serpentine to the gran- itic rocks on Staten Island, I have no new observations to record and do not think that the exposures admit of more plausible explanation than the hypothesis advanced by me in my original communication, where the serpentine was regarded as overlying the other rock, and is so represented in my diagrammatic sec- tions. There is certainly no other rock exposed within the ser- pentine area Jaid down on my map. Of course, this considera- tion applies to the Staten Island outcrops alone ; elsewhere they are inclosed by the gneisses, etc., and this superposition does not occur. Doubtless the Staten Island rocks were originally depos- ited in a conformable sequence, but the serpentines were left on top in the folding of the strata. The idea advanced by me that the serpentine ridge is an anticlinal fold must be abandoned in the light of more recent investigations; it is quite evidently made up of a series of smaller folds which, collectively, are more probably of synclinal structure, though the exposures are not sufficient to satisfactorily settle this question. In my original paper, I stated that these crystalline rocks of Staten Island probably extend southwestwardly across New Jer- sey to Trenton, forming an axis which marks approximately the junction of the Triassic and Cretaceous formations. This imag- Inary axis was indicated on the accompanying maps and sections. Proof of the general truth of this hypothesis is now furnished from a well recently bored near Perth Amboy, which reached gneiss at a depth of seventy feet. This was immediately over- laid by Triassic red shale, about twenty feet in thickness, the latter covered by Cretaceous clay and sand, pre-glacial drift and morainal deposits. A note on this well may be found in the annual report of the State Geologist of New Jersey for 1885. It will be noticed that here the Triassic strata are comparatively thin, and this point is doubtless very near its southeastern margin. I have regarded these metamorphic rocks as Archean, and have thus alluded to them. I am well aware that they are by others considered to be of Lower Silurian age, and that this the- 16 TRANSACTIONS OF THE [ocr. 11, ory is supported by no less authority than that of Professor Dana. But after a careful and prolonged examination of most of the localities on which this theory is based, [ am of the opin- ion that the occurrences can be more satisfactorily explained, and adhere to my belief that they are Archean. It may here be. remarked that Mr. Merrill is about undertaking a critical study of Westchester County, and that we may promise ourselves the presentation ere long of evidence which will go far towards provy- ing the truth of one or the other hypothesis. Triassic Rocks.—No additional exposures of shales, sand- stones, or trap have come to light since my first communication. The wells of the Crystal Water Company are within the area surmised to be underlaid by the Triassic red rocks, being between the southwestern end of the trap dyke and the serpentine hills, but were bored in the drift. Cretaceous Strata.—Here also there are no additional expo- sures to record. ‘The kaolin and fire-clay continue to be mined in considerable quantity near Kreischerville. From the known outcrops and exposures, there must be a large tract of territory underlaid by these valuable materials, though much is deeply covered with glacial drift. The discovery of vegetable fossils similar to those of Woodbridge and South Amboy, N. J., has already been announced to the Academy and noted in the Trans- actions, Vol. V., p. 28. No opportunity has since been afforded for the collection of additional material at this locality. If, however, the vegetable remains in the ferruginous sandrock at Tottenville are, as they appear to be, Cretaceous, it should be recorded that Mr. Hollick has obtained a considerable addition to his previous collections from that point. He has described the occurrence of these fossils in the ‘‘ Proceedings of the Nat- ural Science Association of Staten Island” of Dec. 8th, 1883, and compared them with the specimens from Glen Cove, Long Island, in the Museum of Columbia College, which Dr. New- berry has already exhibited to the society. Pre-Glacial Drift.—Myr. Hollick has recently found an addi- tional outcrop of this interesting formation. It is near the vil- lage of Woodrow and at considerable elevation, though not as high up as the great deposit on Todt Hill. Deposits of Limonite.—Owing to the low prices obtainable for iron ore, but little work has recently been done on these deposits. Very little material has been excavated, and no new beds have been explored. On Todt Hill there is a small amount of pyrite associated with the limonite, which in its decomposition produces Copperas; and this mineral may be noted as new to Staten Island. Dr. Hunt visited the Todt Hill mine with me some three years ago, and has since expressed his opinion that the ore 1886. | NEW YORK ACADEMY OF SCIENCES. 17 is the result of the decay of the underlying serpentine. I had regarded it as a deposit from springs, but am now inclined to believe that Dr. Hunt is correct in his view, and that these ores have originated in a similar manner to that which has produced other Appalachian limonites ; though the presence of much sili- ceous matter with the ore and of magnetic iron sand in some of the deposits indicate that deposition from solution may have produced some of the material, and the black sand must have been mechanically washed in. Glacial Drift.—On my geological map published in the An- nals, Vol. I1., plate xv., the southern boundary of the Glacial Drift is indicated by a dotted line. I have since retraced this line, but have no essential alterations to make in it. The construction of the deep cutting and tunnel for the Staten Island Rapid Transit Railway, at Tompkinsville, has ex- posed a most interesting section through the Glacial Drift. This is seen to be truly morainal in its upper portion, consisting of large angular boulders and pebbles irregularly imbedded in unassorted clay and sand. ‘The lower part of the bank is, how- ever, beautifully stratified and the materials composing it are sorted into bands and layers of different substances, strata of sand of several degrees of coarseness, others of clay, and still others of pebbles ; very few boulders occur in this lower part, and these are in special well-marked bands and are more rounded than those above. While this exposure is of great interest as illustrating the dif- ference between morainal and stratified drift at a glance, it is of much greater importance as furnishing a measure of the depres- sion of the coast at this point during the Glacial Epoch: for the altitude of the upper line of stratification above tide gives us the comparative position of the coast as regards its position in Glacial times. ‘This is between 25 and 30 feet. Hence we may safely conclude that during the presence of the great ice sheet the shores of New York Harbor stood at least that amount lower. As is well known, the coast is at present suffering depression. How much higher it has been since the retreat of the glaciers, or to how many oscillations it has been subjected since that time, are fair subjects for speculation, but cannot now be satis- factorily answered. I have observed the stratification of the drift at other places in the vicinity, but nowhere have I seen such a beautiful exhibition of it as here. Nearly Drifiless Areas North and West of the Terminal Moraine.—This is a feature of the glaciation of the region which was not apparent to me until a year or so ago. There are at least two of these on Staten Island. One is on Pavilion Hill, at Tompkinsville Landing, where there are but very few 18 TRANSACTIONS OF THE [ocr. 18, erratic boulders over a limited area, and the shattered serpentine comes directly to the surface. ‘his hill is by no means the highest ground in the vicinity, but the ice-sheet appears to have flowed around it, there being well-marked moraines on all sides. The highest points on the island are farther southwest, and here the terminal moraine is heaped up on the serpentine ridge. The hill under consideration is near the western edge of the Upper Bay, and it would seem as though the glacier had been diverted by it eastwardly towards the Narrows, it not being overridden by the ice. The other area alluded to is west and southwest of Woodrow, on the high ground of the southwestern portion of the island. This is of much greater extent than the one above described, and there is scarcely a boulder to be seen within its limits. I have not had opportunity to define its boundaries, but am well satisfied of its occurrence. The soil is sandy and may be part of the Pre-Glacial Drift system; the outcrop of this recently found by Mr. Hollick is within its bounds. It is not appreci- ably yellow, however, and it is possible that it is underlaid by one of the cretaceous sand beds. More field observations are needed to settle this question. The subject was discussed by the PRESIDENT, Mr. MERRILL, PROFESSOR MARTIN, and Mr. McDoNaALp. October 18, 1886. STATED MEETING. The President, Dr. J. S. NEWBERRY, in the chair. One hundred and twenty-nine persons present. PRESIDENT NEWBERRY read a paper on EARTHQUAKES, WHAT IS KNOWN AND BELIEVED ABOUT THEM BY GEOLOGISTS. From all quarters have come to me inquiries about the earth- quake in Charleston. Because I am a teacher of geology it has been taken for granted, quite gratuitously, that I knowor ought to know, all about the earth of which the structure and history are the geologist’s special objects of study. That he knows more about these than other people is possible, but that he knows all about them is unfortunately far from true. It is, however, nat- ural that I should be appealed to for information in regard to what is the most striking of all terrestrial phenomena; and while I do not claim nor accept the title of ‘‘ Professor of Earth- 1886. | NEW YORK ACADEMY OF SCIENCES. 19 quakes,” which one correspondent seriously gives me, I ac- knowledge it as apart of my duty to satisfy, as far as I am able, the demand which has been made by the public. I shall, there- fore, present a brief review of what is known and believed in regard to the phenomena and causes of earthquakes, by those whose opinions on this subject are most worthy of confidence. There is something particularly unsettling and terrifying in the upheavals and undulations of what we call ¢erra firma, be- cause it has been accepted as the type of stability. To men of all countries and ages, civilized and savage, the earthquake has been a peculiar terror and mystery. Even the most stoical and reasonable have lost their self-possession when they have felt the solid earth heaving and groaning beneath them; and in the countries where earthquakes are most common, the horror and dread they inspire are never lessened by familiarity, but every new shock produces fresh and increased alarm. It is not sur- prising, then, that in a region like Eastern North America, which has been supposed to be exempt from serious catastrophes of this kind, the occurrence of such an event as that which re- cently took place at Charleston, has produced a profound and widespread sensation. It has not only called out strong ex- pressions of sympathy with the sufferers, but has excited the keenest desire to know all that can be known of this and similar phenomena. It has been the common subject of conversation throughout the land. The journals have been full of descrip- tive details. Scieftists of all kinds have been interviewed, and been made to give their views, if they had any; if not, they have been supplied to them. As a consequence, many wild and -contradictory statements have been made, and so many theories advanced, that the public has hardly known what to believe. Yet earthquakes are neither novel nor mysterious, but are among the most common and simple of terrestrial phenomena; they have certainly recurred at frequent intervals throughout all geological time of which we have any record, and it is prob- able that now, not an hour, perhaps not a minute, passes, but more or less violent vibrations take place somewhere on the earth’s surface. In later years, earthquakes have been carefully studied in many countries by geologists and physicists, and the conclusions reached have been so generally harmonious that there is now very little difference of opinion as to their cause, and the manner in which this cause operates. Briefly told, an earthquake is a movement caused by a shrink- ing from the loss of heat, of the heated interior of the earth, and the crushing together and displacement of the rigid exterior as tt accommodates itself to the contracting nucleus. I cannot, in the limited space now at my disposal, give any- 20 TRANSACTIONS OF THE [oot. 18, thing more than a summary of the facts upon which this state- ment rests, but I may say that they are so numerous and signi- ficant that the conclusion deduced from them, enunciated in the above paragraph, is not only convincing, but inevitable. I will briefly notice some of these facts. From observations in mines, and from deep borings, from hot springs and volcanoes, we have learned that the interior of the earth is intensely hot. ‘The most satisfactory data for this con- clusion are furnished by wells and mines. ‘hese are located in all the great divisions of the earth’s surface; China, India, Aus- tralia, Africa, Europe, and North and South America, all have their mines or deep borings, which give fairly harmonious testi- mony upon this subject. They prove that after passing the plane of invariable temperature, beyond which the alternations of the seasons are not felt, the heat increases about 1° Fahr. for every fifty feet; for example, the well in the grounds of the Lunatic Asylum at St. Louis is 3,843 feet in depth; at 3,200 feet, where the temperature was last observed, it was 107°; the State House well, at Columbus, Ohio, is 2,775 feet deep, and at 2,575 feet the temperature is 88°. The artesian well at Louis- ville, Kentucky, is 2,080 feet deep, and the temperature at the bottom is 82°, summer and winter. Other wells bored in the Valley of the Mississippi and in the Eastern States furnish sim- ilar data. In Europe, many deep mines and wells have afforded facts co- incident with those I have reported from this country ; for ex- ample, the well of Grenelle, at Paris, is 1,800 feet deep, and the water which flows from it has a temperature of 82° Fahr., while the mean annual temperature at the surface is51°. A well bored at Sperenberg, Germany, to the depth of 4,172 feet has a tem= perature, at 3,390 feet, of 115,5° Fahr., whilea well at Schladen- bach, 5,286 feet deep, has a temperature at bottom of about 131°. Wells in China, India, and Australia show a corresponding in- crease of temperature in descent, although few quantitative ob- servations have been made there. There are some exceptions to the rule that the temperature increases at the rate of 1 degree for every 50 feet in descent; for example, in the mines on the Comstock Lode, Nevada, at the depth of 3,200 feet the temperature is 160° Fahr., an increase of about 1 degree for every 29 feet of descent. This case and simi- lar ones at Monte Massi, in Tuscany, and at Buda-Pesth, Hun- gary, are quoted by Professor Judd, in his Volcanoes, and are considered of sufficient importance to invalidate the evidence of thousands of other mines and wells. But the exceptions only prove the rule. The wells mentioned are located in regions which not long since, geologically speaking, have been the 1886. | NEW YORK ACADEMY OF SCIENCES. 21 scenes of violent volcanic action. The surface of the country is occupied by vast sheets of lava, hot springs abound there, and it is evident that the subterranean fires are not yet extinguished. A boring on the flanks of Mt. Etna would be a still more strik- ing exception to the rule of one degree for every 50 feet, and would be equally legitimate evidence against it. Excluding these abnormal cases, which really have no bearing on the question, the irregularities in the rate of increase in tem- perature are not greater than those which might be caused by differences in the conductivity of the rocks passed through. The deep wells of Sperenberg and Schladenbach—which were bored in part to test this question, and have been the most carefully observed of any—have given the most convincing evidence of the truth of the theory of intense internal heat.’ The case cited by Professor Judd (Volcanoes, p. 341), ‘‘a deep well in Buda-Pesth, in which there was a decline of temperature below 3,000 feet,” is probably a mistake or a fraud. The same thing happened at the deep well at St. Louis, in which the tempera- ture increased regularly to the depth of 3,200 feet, where it was 107° Fahr. Below that the contractor reported the temperature declining, because the directors were about to stop the work, partly on account of the warmth of the water! To prevent exposure of the fraud, iron rails were dropped into the well. It may then be considered as established that all over the earth’s surface, except in volcanic districts, the temperature in- creases about one degree Fahr. for every 50 feet descent. It is evident that should this rate of increase continue, the tempera- ture at the depth of 50 miles would be sufficient to melt all known substances; and the first conclusion from the observation of temperature in mines and wells was that the solid portion or crust of the earth could not be more than 40 or 50 miles in thickness, and it was proclaimed that we were living on a film of solid matter, floating on a sea of molten rock. The com- parative stability, however, of the earth’s figure—the little 1 Some of the temperatures in the Schladenbach well are as follows: Depth in Metres. Temp. Fahr. Réaum, 1266 113.5° 36.2° 1296 115, 36.9° 1326 116.8° 37.7° 1356 1197535 38.8° 1386 121.3° 39.7° 1416 122.9° 40.4° 1506 127.2° 42.3° 1566 128.3° 42.8° 1596 130.1° 43.6° 1626 131.° 44,° 22 TRANSACTIONS OF THE [oor, 18,5 effect produced by the attraction of the sun and moon—have led to the conclusion that the earth’s crust is thicker than this, and it has been suggested that while the accuracy of the obser- vations on the increase of temperature to the depth of one mile cannot be questioned, it is possible that the rate of increase to that depth is not constant below; that the increment may diminish, and therefore the temperature of fusion may only be reached at a greater depth than has been supposed. It has also been shown that the melting point of many sub-- stances is raised by pressure, and therefore, that the enormous weight of the overlying rocks, equivalent to 792,000 lbs. to the square foot for every mile, may hold in coerced rigidity a con- siderable zone of the earth’s mass composed of materials that would melt and flow on the surface at a much lower temperature than that which they now endure in a solid form. Accepting, then, the conditions imposed on the old theory of the state of the interior of the earth by pressure and the possible diminution of the increment of temperature, we may suppose that the solid crust is considerably thicker than was formerly supposed. That it is relatively thin, however, is indicated by facts which will be cited further on. The increase in temperature observed in mines and deep bor- ings means that the heat of the interior of the earth is constantly escaping to the surface, where it is radiated into space. If the outer crusts were a perfect non-conductor, the materials within it would always maintain a condition of thermal equilibrium throughout. It is thus evident that the process of refrigeration is progressive, and from the time when the first film of solid matter dimmed the brightness of the ‘‘ glittering globe of liquid fire,” the crust formed at the surface has been constantly increasing in thickness, while by the loss of heat, which is an expansive force antagonistic to gravity, the volume of the earth has been as constantly diminishing. But since the outer crust has lost its inherent heat and has become solid it no longer shrinks, though the loss of volume goes on incessantly in the in- tensely heated, but gradually cooling interior. As the nucleus contracts the solid crust cannot accommodate itself moment by moment to the loss of volume, for it resists by its rigidity and is brought into a state of strain. This is relieved from time to time, whenever it passes the resistance of the materials compos- ing the crust, by a crushing together and displacement of the surface rocks. ‘These are faulted or folded ; that is, are either thrown into great waves by lateral pressure, or the arches are. broken and fissures are produced at right angles to the line of thrust. The rocks forming the sides of these fissures slide on each other, forming what geologists call faults, in which the 1886. | NEW YORK ACADEMY OF SCIENCES. 23 *‘throw” or displacement sometimes amounts to many thousand feet. Harthquakes, mountain chains, and voleanic eruptions may all be considered as consequences of this readjustment. Moun- tain chains are great lines of fracture in the earth’s crust along which rocks before nearly horizontal are raised into ridges by’ lateral pressure. They have been compared, not inaptly, to the wrinkles formed in the rind of a fruit when it loses its volume by drying. Kvery mountain chain shows many foldsand faults; in the Alleghanies the folds are noticed by every traveller, and few better examples of folded strata are seen anywhere than those which border the gorge which cuts through the ridges from Cumberland to Frostburg, Maryland. The faults are less conspicuous and would hardly be detected except by a geologist, but they are very numerous, and in some of them the displace- ment is more than 20,000 feet. The Wasatch Mountains in Utah —one of the boldest ranges on the continent—owe their relief mainly to a fault which runs nearly north and south through the middle of the Territory. The country west of this fault is thrown down and that on the east raised to form a wall 5,000 to 7,000 feet high. It is evident that the folds and fractures seen in every moun- tain belt could not have taken place without great disturbance of the surrounding country. And as they have been formed, not all at once, but each by itself, and each one by many paroxysms, an almost infinite series of earthquakes is recorded in the struc- ture of every mountain chain. A large number of earthquakes of modern times have been attended by changes of topography which have remained as evidences of the displacements which caused the vibrations. Sometimes a line of coast was raised above the ocean level, sometimes mountains or cliffs split and fell, sometimes fissures and faults were formed many miles in length. eines thing about mountain chains is not so generally known as that they are lines or belts of folded and fractured rocks ; and that is that they are the products not of moments or even years, but of ages. The lines of fracture which are marked by mountain chains are ever, after the first disruption, lines of weakness, where the resistance to lateral pressure is diminished, and where the strain of large unbroken areas is relieved from time to time by displacements, necessarily attended by earth- quakes. I have sometimes compared them to hinges on which the great tables of the earth’s crust turn with constantly chang- - ing angles. Generally mountain chains may be said to grow by the constant or paroxysmal elevation of their arches, the increase in the throw of their faults. This growth would be much more apparent than it is, if it were not that the mountain chains re- 24 TRANSACTIONS OF THE [ocr. 18, ceive a far greater precipitation of moisture than the lowlands, and erosion, which is the opposing force to elevation, counter- acts its effects. The East Indian geologists estimate that in the Himalayas the process of elevation is going on constantly, and that it is at least equal to the loss from denudation. The application of all that has gone before to the Charleston earthquake is simply this: that we learn from the facts cited that displacements are constantly taking place in the crust of the earth the world over, and as these affect rigid and resistant masses of rock they are produced per saltwm, that is, in parox- ysms. The strain accumulating until it overcomes the resist- ance is released in one or many efforts, each of which is attended by an earthquake vibration of greater or less force. ‘The coun- try bordering a disturbed belt is sure to feel the effects of sub- terranean movements more frequently than plains and plateaus removed from mountains. Every year we hear of local disturb- ances in the Southern Alleghanies, and Bald Mountain has been the scene of so many that it has come to be looked upon with awe and apprehension by the people in the vicinity. So along up the Atlantic slope of the Alleghanies there have been many earthquakes since the country was occupied by whites. Not a year passes that we do not hear of several in New England, the Middle or Southern States. As the population increases, the number of observers is multiplied and the number of struc- tures liable to damage constantly added to; so that such pheno- mena now attract more attention and cause greater destruction than formerly. In New England the best record of earthquakes has been kept, and if any one will look over a file of newspapers published at Boston or Hartford, he will find that within the last century a very large number of earthquake shocks or vibra- tions are noticed. Earlier than that, we must depend upon town records or private correspondence. From these we learn that in 1727 the country about Newburyport, Mass., was shaken up, very much as Charleston has recently been, but in that re- gion there were then but few buildings and those of wood; so that the damage was comparatively small.’ Two years ago, New York City suffered an earthquake shock, but fortunately not a severe one. It occurred about two o’clock Sunday afternoon, the 10th of August. I was sitting alone in my room in the College, where all was perfectly still; suddenly I heard a heavy rumbling sound like that of a passing loaded 1 Since this paper was written I have received ‘‘ Historical Notes on the Earthquakes of New England from 1638 to 1869,” by William T. Brigham, published in the Memoirs of the Boston Society of Natural History, 1868. This contains notes upon two hundred and thirty-one earthquakes, with many interesting details. 1886. ] NKW YORK ACADEMY OF SCIENCES. 20 wagon ten times magnified. At the same time the building be- gan to vibrate, the windows rattled and some light objects were disturbed and fell to the floor. I was sensible of a tremor that not only jarred, but swayed my body and caused my book to vi- brate and swing in my hand. I recognized the nature of the phenomena at once, observed the time and made a note of it. Subsequently, going into the geological cabinet, I found palpable evidence of the force of the vibrations. Ina case occupied by specimens of marble, many of which were set on edge against the back of the case, all such were thrown down and some were broken. As the back of the case was toward the north, this proved that some of the vibrations were from that direction. _ This earthquake was noticed by a number of observers, and their testimony showed that the area affected was, as usual, el- liptical in outline, and extended from Washington, D. C., to Portsmouth, Me., and from Harrisburg, Pa., to the Atlantic. In the Old World, observations on earthquake vibrations have been reduced to a system, and instruments called seismographs or seismometers have been devised. which make an automatic record of the time, direction, and force of the vibrations. Where such instruments are scattered over a country it is evi- dent that the outline of the area affected by an earthquake shock, as well as the geographical position and depth of the centre of motion, may be accurately determined. In Japan, where earthquake vibrations are almost incessant, an extended system of observations has been instituted by Prof. Milne, which are likely to throw much light upon this subject. In this country there are few seismometers, and no carefully regulated system of observation has been yet adopted, but it is probable that one good effect of the Charleston earthquake will be to excite an interest in such phenomena that shall result in the organization of a thorough system of observation. The officers of the Geological Survey and Signal Service Bureau are taking an active interest in the matter, and it is probable that observations on the movements of the earth will be added to those they are now making on the movements of the atmosphere. When the data already collected in regard to the Charleston earthquake shall have been tabulated, it will doubtless be found that the displacements which occasioned the vibrations were lo- cated along a line parallel with the Alleghanies and at a depth -of 10,000 to 20,000 feet, not under, but westward of the city. Inasmuch as no great change took place on the surface of the land in South Carolina, it has been suggested that the seat of the movement was under the ocean, and that important changes may have taken place in the topography of the sea bottom. It as quite certain, however, that such was not the case; for any 26 TRANSACTIONS OF THE [ocr. 18, considerable movement beneath the ocean in the vicinity would have resulted in a great wave upon the shore, such as have at- tended many other earthquakes, viz., that of Kingston, Jamai- ca, in 1692, of Lisbon in 1755, or that of Arica, Peru, in 1868. No wave at all is reported on the coast of South Carolina, though a distinct shock was felt on board a ship which had just left Charleston. This proves that the seat of the disturbance was not under the sea, but on the land, the vibrations passing from the land seaward. It is reported that a slight change in the depth of the water in Charleston Harbor has resulted from the earthquake, but no accurate observations have been made to test the truth of the report. In all probability the movement was in the old crystalline rocks beneath the comparatively mod- ern deposits which underlie the surface, and consisted in a~ yielding to lateral thrust which ruptured and slipped some of the beds over others. Such fracture and movement would pro- duce vibrations which would take the form of successive waves passing vertically, upward and outward in every direction from the focus of action. As the older rocks which underlie this region dip toward the east and have a strike north and south, an im- pulse produced by disruption would move north and south in continuous strata, and east and west through a succession of beds which would be less good conductors. Hence the area of vibration will doubtless be found to be an ellipse with its longest diameter north and south. One fact reported from Charleston is very interesting if true, and that is that the railroads leading westward were shortened; the rails being arched much out of line. To straighten the roads, it is said to have been necessary to cut out ‘‘ here one foot,” there two feet,” etc., of the rails. This shortening, if verified and measured, would give a clue to the location and extent of the subterranean movements which produced the vibrations. The determination of the depth of the focus of action in earthquakes is generally a difficult problem from the lack of ac- curate observations. Where the angle of emergence of the earthquake waves can be ascertained, even along a few lines, it is easy to fix the point where these lines intersect. In this way the depth of focus of many earthquakes has been determined. Mr. Mallet, who has made the most elaborate study of earth- quake phenomena, gives the maximum depth at 83 geographical miles and the minimum depth at 2? miles; but Dr. Oldham, late director of the Geological Survey of India, estimated the focus of action in the great Cachar (Bengal) earthquake of 1869 to be from twenty-five to thirty miles in depth. The bursting out of temporary springs or fountains of water carrying quantities of sand has been mentioned as a remarkable 1886. | NEW YORK ACADEMY OF SCIENCES. 27 feature in the South Carolina earthquake, but this is a phenom- enon common to many earthquakes, and is specially noticed in the accounts we have of those of Newburyport of 1727, and New Madrid, 1811. It is, doubtless, due to the pressure exerted by the earthquake-wave on subterranean reservoirs of water, or the compression of water-bearing strata. Another circumstance, which has excited some curiosity, is the twisting of chimneys and monuments on their foundations. This has been noticed among the consequences of many earth- quakes, and it has been generally attributed to a gyratory move- ment of the earth, but Mr. Mallet has shown that this is not a necessary conclusion, but that an adhesion to one part of the foundation would cause a revolution of the superstructure about this point. It will be noticed that, in the reports which have been given of the Charleston earthquake, there is an absence of all refer- ence to the explosions which have been among the most striking and destructive phenomena of earthquake action in some locali- ties. Thus, in the description of the great earthquake of Rio- bamba, Equador, in which 40,000 persons perished, it is said that the bodies of many of the inhabitants were thrown upon a hill which rose to the height of 100 feet on the other side of a stream; and, during the earthquake of Chili, 1837, a mast, planted 30 feet deep, was thrown out so that a round hole re- mained behind. ‘These, which are called explosive earthquakes, have been confined to the vicinity of volcanoes and to districts bordering on the sea, and it is supposed that, by the disruption of the rocks, large quantities of water have been suddenly brought into contact with melted lava. Steam has played an important part in most volcanic eruptions, though as a second- ary, and not, as often supposed, a primary cause. Masses of molten matter, welling up through fissures in the earth’s crust, must necessarily come in contact with subterrean reservoirs of water, or with strata saturated with moisture. In the vicinity of the sea, too, where most volcanoes are located, water may be admitted in the manner just described. In all these cases, steam would be generated in such quantities as to make this an efficient adjuvant to the lava flood in producing disruption, up- heaval, and vibrations of the rocks. ‘The absence of these vio- lent features in the earthquakes of the country bordering the Alleghany belt proves that volcanic action has had nothing to do with them, and shows that, like a vast majority of earth- quakes elsewhere, these have been, as Dana says, ‘‘ incidental phenomena in the process of mountain building;” that is, they are sensible signs of the lateral movement of the earth’s crust which results in the crushing, folding, faulting, elevation, and 28 TRANSACTIONS OF THE [oct. 18, metamorphism which are distinctive features of all mountain belts and chains. Where this action takes place on a grand scale, and involves the entire thickness of the earth’s crust, mountain chains of great elevation, length, and breadth are the result, and, through profound fissures opened to the zone of molten material below, lava rises and overflows. In the Triassic age, such deep fissures were opened along the Atlantic border of the continent, as is attested by the trap sheets and dikes which extend interruptedly from Nova Scotia to the Carolinas. At that time, the whole coast must have been shaken with earth- quakes of great violence, and much of it devastated by lava- floods. Since then, the earth’s movements have been only the relatively gentle vibrations caused by the yielding of the flexed and fractured rocks of the upper portion of the crust to the ever acting and resistless thrust of the great unbroken tables of the Mississippi Valley and the Atlantic basin. EARTHQUAKES AND VOLCANOES AS MEASURES OF THE THICK- NESS OF THE EARTH’S CRUST. As is mentioned in the early part of this article, the first re- sult of the discovery of the law of increase of temperature in going toward the centre of the earth was the conclusion that the solid crust was not more than 50 miles in thickness, and below that was a sea of fluid or semifluid molten matter. Then moun- tain chains were supposed to be the result of the crushing to- gether of solid sheets of rock as they followed the cooling and shrinking interior. The coat becoming too large, and adhering to the body, must wrinkle as the body shrank. Volcanic erup- tions were supposed to be the oozing out of molten matter from the not distant zone of fused material, and all was harmonious in the geological world. Then came Professor Hopkins, Arch- deacon Pratt, and Sir William Thomson, in the character of dis- turbers of the public peace; they said that the crust would be broken up by tides if it was as thin as supposed; that the shell would be pulled about on the fluid nucleus by the attraction of the moon on the equatorial protuberance; and, finally, that the tenacity with which the figure of the earth is maintained under the varying pull of the sun and moon made it necessary to sup- pose that it was, as a whole, as rigid as a globe of glass, or even of steel. Sir William Thomson conceded, with some hesitation, that the crust of the earth might not be more than 2,500 miles in thickness; further than that he would not go. Since that time, awed by his great and well-deserved fame, geologists have generally accepted the conditions he imposed upon them, and there has been a terrible struggle to reconcile volcanoes, earth- 1886. | NEW YORK ACADEMY OF SCIENCES. 29 quakes, and the flexibility of the earth’s crust with a solid in- terior. Some have gone back to Sir Humphry Davy’s theory, that volcanoes were the product of intense chemical action in certain circumscribed portions of the earth’s mass; and others have supposed that, between a thick external crust and a solid interior there was an intermediate zone of fused matter from which volcanic ejections emanated. Mallet, who has displayed great learning and ability in his various papers on volcanoes and earthquakes, forbidden by Sir William Thomson’s dictum from drawing molten matter from the interior of the earth to operate his volcanoes, contrived a method of manufacturing it on the spot. He proposed a theory that all the phenomena of vulcanism are due to the arching of the exterior strata composing the earth’s crust, their final yielding to gravity and crushing down on to the contracting interior; the conversion of motion into heat produc- ing all the thermal phenomena. A fatal defect in this theory is that it gives no reason for the localization of the heat along the line of fissure from which the lava flows. All parts of the masses on either side must share in the motion and should also share in the heat, and we must look elsewhere for an explanation of the phenomena." There would have been no question of the truth of the old theory of vulcanism if it had not been raised by the physicists whose names have been mentioned, and it can now be seen that their objections have little force. Delaunay, of Paris, and Hen- nessy, of Dublin, have shown that the premises assumed by Thomson, Hopkins, and Pratt in their attempted refutation of the old theory of a comparatively thin crust are not those of nature, and that their conclusions are, as a consequence, irrel- evant and valueless. ‘Their objections were aimed at an incom- pressible fluid interior and an elastic crust ; conditions which do not and could not exist. Beside this there must be a viscous zone of considerable thickness in which the transition from the solid crust to the liquid interior is very gradual ; and it is highly probable that the matter of this viscous zone is not only not it- 1In a review of Mr. Clarence King’s report ‘‘On the Geology of the Country Bordering the Fortieth Parallel,” the writer in 1879 suggested a simple explanation of the phenomena of vulcanism, viz., A slight arching of the crust of the earth along lines of fracture and elevation, in a measure relieves the pressure by which highly heated matter below is kept in coerced solidity. This relief of pressure causes the potential fluidity of this compressed matter to become actual, and thus reservoirs of lava are called into existence beneath the lines of fracture and arch- ing. Finally the pressure from gravity being maximum under the tables of unbroken strata on either side, and minimum beneath the crown of the arches, this unequal pressure causes the lava to rise along the fissures and flow out in volcanic eruptions, 30 TRANSACTIONS OF THE [oct. 18, self affected by tidal movements, but that it acts as a buffer be- tween the liquid interior and the solid crust. It should be re- membered that the moon’s attraction—the chief motor in oceanic tides—is a force applied to a surface moving at the equator about a thousand miles an hour. Even a fluid as thin as water refuses to obey instantly an attracting body. The tidal wave of the ocean is. always considerably behind the moon, and in some places where obstructed by topographical features it does not reach its destination until some time the next day. It is easy to see that in a tarry, pitchy mass the response to the moon’s attraction would be far less prompt, and also that the tidal waves in zones of different depths and densities would not coincide, and might completely neutralize each other. Every boy knows that if a flat rock is thrown from a cliff on to water some distance below, it is shattered almost as though it fell upon asolid; but the velocity of a falling body im vacuo is 16 feet the first second, 48 the second, etc., and with the resistance of the air, it is doubtful whether a stone thrown from a cliff 100 feet high reaches the water with a velocity greater than 50 feet a second, while the velocity of impact, if we may use the ex- pression, of the moon’s attraction is nearly 30 times greater than that, or 1,466 feet per second. ‘The resistance which the internal friction of a viscous body would offer to a force applied with such velocity would be enormously greater. Hence we must conclude that the tidal movement in such a mass even at the earth’s sur- face must be very small, and if, as is the case in the interior of the earth, that mass were condensed and constrained by the weight of a crust even a hundred miles in thickness, it would be inappreciable. It should be remembered that the force of grav- ity acting upon a column of matter one foot square and having the density of the materials composing the earth at the surface, that is 24 times that of water, is 792,000 lbs. for every mile, or 79,200,000 lbs. at the depth of 100 miles. Sucha pressure must greatly increase the density of matter of any kind. ‘The average density of the earth is 54 times that of water, and it is plain that in matter of this density and so situated not only a tidal wave would be impossible, but any attraction which is constantly and rapidly changing its point of bearing must be practically powerless to distort the figure of the earth, FLEXIBILITY OF THE EARTH’S CRUST, It is difficult to imagine how the advocates of the theory of a solid globe can account for the formation of mountain chains, the loftiest and longest of which are quite modern; and it is not perhaps too much to say that these themselves are a refutation of their theory. It isevident that a heated solid globe, as it lost 1886. ] NEW YORK ACADEMY OF SCIENCES. 31 its heat, would either contract bodily as a red-hot cannon ball does, or by the more rapid cooling of the outer surface, that would shrink faster than the interior, and crack in every direc- tion; a process just the opposite from that which we find re- corded in the earth’s crust. But there are other evidences of the flexibility of the earth’s rust which are incompatible with the theory which ascribes to it great thickness. (1.) The lines of volcanoes which crown most great mountain chains are located along fissures which seem to be continuous for thousands of miles, and there is appar- ently good evidence that these fissures penetrate through the entire thickness of the solid crust. Sometimes the volcanoes are in simultaneous action for several hundreds of miles, and the materials ejected, though showing much variety, are often identi- cal: facts incomprehensible on any other supposition than that they have been drawn from a common reservoir.’ (2.) Along all the coast lines the evidences of local changes of level now in progress, or included in the records of past time, are so numerous and striking that the term ¢erra firma seems singularly ill-chosen ; for example, the shores of the Mediter- ranean abound in evidences of local depressions or elevation, or both, since it has been occupied by civilized man. Of these the temple of Jupiter Serapis at Baiz is one of the most famous, but by no means the only example. On our own continent, the southern portion of Greenland has been gradually sinking for several hundred years; Labrador and Newfoundland are rising; Prince Edward’s Island and Cape Breton, according to Gesner, have sunk many feet since they were first occupied by the whites. In Nova Scotia the land is rising ; in Northern Maine it is sinking, as also at Cape Cod and Martha’s Vineyard and on the shore of Long Island and New Jersey. Here the subsidence has locally varied from two to twelve feet during the last century. In the West Indies, there are many evidences of local change of level; in some cases, of elevation, others, of subsidence. In California, we find traces of recent and local flexures of the coast which are very striking ; at San Diego is an old beach strewn with shells which have not yet lost their colors, twenty feet above the present sea-level. At San Pedro, the port of Los Angeles, the limestone rocks which form the sea cliffs are bored by Pholas eighty feet above the water ; on the south shore of San Pablo Bay, at a height of twenty 1 Darwin mentions (‘‘ Trans. Geol. Soc.,’”’ March, 1838), that in the Andes the volcanoes Osorno, in lat. 40° S., Concagua, in 32° S., and Coseguina, in lat. 13° N., burst into eruption simultaneously on the 20th January, 1835. The more remote of the three are 3,700 miles apart. 82 TRANSACTIONS OF THE [oct. 18, feet above the water, is a bank of oystershells, four feet in thick- ness ; this descends toward the south, and disappears beneath the surface of San Francisco Bay. Puget Sound, with its many branches, is only the submerged valley of a great river which ran out to sea through the Straits of Fuca when the coast was much higher than now; but the shores are terraced to the height of 1,600 feet above the present water-level ; showing that, in recent times, they have been much lower than now. Similar facts with these have been reported from the shores of all the continents, and the islands afford more striking examples of the changes of level ; the Windward Islands are only the summits of a lofty mountain chain which was once all above the sea-level, as is shown by the community of species in animals and plants. The Islands of the South Pacific are, also, the summits of mountains which have been gradually submerged, as has been shown by Dana and Darwin. Coral reefs which are formed only within 150 feet of the surface now extend down in continuous walls, 2,000 feet below the water; the growth of the coral having kept pace with the gradual subsidence. LElisée Reclus, in La Terre, and Profes- sor Prestwich, in his Geology, give maps, showing the fluctuations of level now in progress along coast lines; and whoever will ex- amine these maps will find it difficult to reconcile these oscilla- tions of the land with a globe solid to its centre, or even with a thick crust. But the changes of level now taking place proceed so slowly that the record of one hundred and fifty years, during - which geological observations have been made, or even that of the long period covered by human history, is insignificant, compared with that of the geological ages. Indeed, historical geology is, for the most part, but a transcript from the monuments left by suc- cessive and local subsidences of the land, influxes of the sea, and the deposition of strata containing relics of the marine and terres- trial life of the epochs in which these inundations occurred. Searce any portion of any continent is without traces of the pres- ence of the sea, and, while some of these submergences were, doubtless, caused by great tides which ebbed and flowed from one hemisphere into the other, in the manner suggested by Adhemar, it can be easily shown that most of them were occasioned by local subsidences of the land. All these lines of evidences, furnished by earthquakes, moun- tain chains, volcanoes and terrestrial oscillations, converge to one point, and, in combination, go far to prove that the earth’s crust is relatively thin, and that its interior is fluid or viscous. A priori considerations confirm this conclusion. If, as all believe, the earth was once a globe of molten matter which has cooled by radiation from the exterior, it seems impossible that the first formed crust could have sunk to the centre, and there 1886. | NEW YORK ACADEMY OF SCIENCES 33 laid the foundation of a solid structure, subsequently built up to the surface. Because, first, there is no probability that the superficial crust had a higher specific gravity than the underly- ing fluid ; and, second, if its gravity were greater, and when broken up its fragments sank, they must soon have been melted by the greater heat below ; and when, by this process, the outer zone of the earth had acquired a pasty consistence, its cohesion could not have been overcome by sheets of crust, even if a little denser. Hence, a cool, external crust, a hot, viscous zone, and a hotter fluid nucleus seem logical necessities. PROXIMATE CAUSES OF EARTHQUAKES, Atmospheric Conditions.—If it is true, as claimed on the pre- ceding pages, that earthquakes are the vibrations attending the folding and breaking of rocks which have been in a state of Strain, it is evident that the provoking cause of any special par- oxysm might be a comparatively trifling affair—some feather that should break the camel’s back. Thus, we have reason to believe that atmospheric conditions may precipitate these catas- trophes. The pressure of the atmosphere on the earth’s surface is 14.7 pounds to the square inch—that is, a little over 2,000 pounds to the square foot, or about 30,000,000 tons to the square mile. Now, it sometimes happens that the mercury oscillates two inches in the tube of a barometer in connection with some violent storm; and it is true that the areas of low and high pressure change position quite rapidly. Hence, if it should hap- pen that the underlying rocks were from lateral pressure in a state of strain that had nearly reached the limit of resistance, a change of atmospheric pressure equivalent to two, or even one inch of mercury (equal to 1,000,000 or 2,000,000 tons per mile), might be the cause of a rupture. So, the popular belief, that peculiar atmospheric conditions have had an influence in caus- ing earthquakes, is not so absurd as it might seem. Accumulation of Sediments.—Another cause which has cer- tainly operated to disturb the static equilibrium of the earth’s crust, is the transfer of the products of erosion from the land to the bottom of an adjacent sea basin. Over all land areas where the rainfall is considerable, there is a constant wearing away of the surface by chemical and mechanical agents. About one- fourth of the material removed is dissolved and may be carried to the opposite side of the earth before it is precipitated ; but the other three-fourths, in the form of gravel, sand and clay, are simply held in suspension by running waters and are deposited as soon as their motion is arrested. Rivers, rivulets, and shore waves are constantly engaged in transporting material from the land to the deeper water bordering the coasts; there spreading it 34 TRANSACTIONS OF THE [oot. 18, to make new series of sedimentary deposits. As these accumu- late they not only impose new burdens on the underlying rocks, but by acting as blankets and preventing the escape of heat, they promote the softening and weakening of a belt of sea bottom. This process has produced great changes in the surface topo- graphy of many continents, and it is credited with the forma- tion of a number of littoral mountain chains. ‘The blanketed belt of off-shore sea bottom, softened by heat, yields to lateral pressure, and is forced up in a series of ‘faults and folds. There is little doubt that the loading of the sea bottom with the pro- ducts of erosion has been one cause of the earthquake vibrations which have been so frequent along our Atlantic coast. Periodicity of Harthquakes.—Very naturally an effort has been made to connect earthquakes with the changing relations of the sun and moon. M. Perrey, of Dijon, France, has tabu- lated the records of 2,225 earthquakes which occurred between the years 306 and 1845. Of these he found that 1,712 took place in winter and spring, and 1,335 in summer and autumn. By Mr. Robert Mallett between 6,000 and 7,000 earthquake shocks are enumerated as having taken place in Europe only. Judging from all these it seems that earthquakes are a little more fre- quent when the attractions of the sun and moon are combined or opposed—that is at new and full moon—and when the earth is nearest the sun. These data, although still defective, tend to support the theory of the fluidity of the interior of the earth, and confirm the tes- timony of volcanoes and of the secular oscillations of the earth’s crust. Areas of Hxemption.—Probably no part of the earth’s surface has been always free from earthquakes. Nevada, Utah, New Mexico and Arizona were in Tertiary times more completely broken up and devastated by earthquakes and volcanoes than any other country known to us, but in that same region profound peace prevailed from the Cambrian to the Cretaceous ages, many millions of years. Since the Tertiary, the Colorado plateau has been remarkable for its stability. This is shown by the sand- stone pillars several hundred feet high standing at the mouth of the Cafion of Chelly, and in the Colorado valley near the junc- tion of the Grand and Green Rivers. ‘These columns have been formed by the slow removal of the material around them, a work of ages; and earthquakes would have brought them down in ruins, as they have shattered the monuments of Baalbeck, Tanis and Karnak. Bibliography.—*‘ First Principles of Observational Seis- mology,” Robert Mallett; “‘' The Facts and Theory of Earthquake Phenomena,” R. Mallett, Reports of British Association, 1850- 1886. | NEW YORK ACADEMY .OF SCIENCES, 35 58; Various papers on earthquakes, by R. Mallett, in the Philo- sophical Transactions and ‘Transactions of the Royal Irish Academy; ‘‘ Geological Theories of Elevation and Earthquakes,” W. Hopkins; ‘‘ Report Brit. Assoc.” for 1847; Oldham and Mal- lett on ‘* The Cachar Earthquake,” Quarterly Jour. Geo. Soc., 1872, p. 255; Scrope’s ‘‘ Volcanoes;” Lyell’s ‘‘ Principles of Ge- ology,” vol. ii.; Prestwich, ‘‘ Geology,” vol. i.; Milne, ‘‘ Karth- quakes,” 1886; ‘‘ Catalogue of Earthquakes of Europe and Ad- jacent Countries,” J. P. O’Reilly, Dublin, 1886; ‘‘ Underground Temperatures,” J. Prestwich, Proc. Roy. Soc., 1886; ‘‘ Water in Volcanic Eruptions,” Prof. J. Prestwich, Proc. Roy. Soc., 1886; “‘Internal Fluidity of the Globe,” M. Delaunay, Geol. Mag., vol. v., p. 507; ‘* Figure of the Karth,” Archdeacon Pratt, 1860; “Rigidity of the Harth,” Sir Wm. Thomson, Phil. Trans., 1863; ‘‘ Inequalities of the Harth’s Surface,” Rev. O. Fisher, Phil. Trans., vol. xii.; Dana, ‘‘ Geology;” LeConte, “‘ Geology; ” L’Apparent, ‘‘ Geologie; ” Hartwig, ‘‘Subterranean World.” October 25, 1886. STATED MEETING. The President, Dr. J. S. NEwBERRY, in the chair. Forty-two persons present. Mr. F. J. H. Merrit read a paper entitled NOTES ON THE GEOLOGY OF BLOCK ISLAND AND NANTUCKET. (Published in the Annals, vol. IV.) PRESIDENT NEWBERRY remarked upon several matters of geological interest in the vicinity of New York. Mr. H. HeNnsoupt, a visitor, stated that he had discovered in a meteorite, which lately fell at Braunfels, near Wetzlar, Ger- many, liquid carbonic acid in cavities in supposed quartz; and he discussed this and other facts concerning meteorites in their bearing upon the question of the earth’s interior. The subject was further discussed by Mr. L. E. CHITTENDEN and the PRESIDENT. November 1, 1886. REGULAR Business MEETING. The President, Dr. J. S. NEwBERRY, in the chair. Fifty-two persons present, 36 TRANSACTIONS OF THE [Nov. 1, The Report of the Council was received and adopted, which recommended the payment of a bill, and the election of Rry. STEPHEN D. Peer, of Clinton, Wisconsin, as a Corresponding Member, and of the following persons as Resident Members : Rev. ANSON P. ATTERBURY, Mr. AucustTIN P. BJERREGAARD, Mr. JAMES S. GIBBONS, Mr. JOHANNES ROELOFFs, Mr. OrLIN MEAD SANFORD. Mr. L. E. CHITTENDEN, in continuing the discussion of the subject of earthquakes, following the paper read by the president at the meeting of October 18th, made observations upon a large number of celebrated earthquakes and their phenomena, with a view to some generalizations as to their causes, After citing numerous reports given by Herodotus and Pliny, showing the frequency of such convulsions, but hardly mention- ing any details, Mr. Chittenden passed over the long period of the middle ages, in which there is but little recorded, and beginning with the close of the seventeenth century, gave brief accounts of some of the most important earthquakes among the many since then known. ‘Those of 1692 in Jamaica, of 1693 in the Kast India islands and in Sicily, and of 1699 in Java, all extremely destructive, were mentioned. An outline was given of the phenomena attending the well-known earthquake at Lisbon in 1755, which convulsed a tenth part of the earth’s surface, reaching the great lakes of America, the West Indies, Scotland, Sweden, and the Baltic. Mr. Chittenden briefly referred to the earthquake of 1762, central near Bengal, where sixty square miles of earth sank into the sea, of Java in 1772, where four thousand feet in height of a mountain were truncated; of Calabria in 1783, with its terrible details, continuous for nearly four years; of Sumbawa in 1815, attended by volcanic explosions heard one thousand miles away, and affecting all the islands within a radius of three hundred miles; of Cutch in 1819, where ever two thousand square miles sank permanently, and a new and navigable outlet of the Indus was formed; and those of Ischia in 1828 and 1882. Like reference was made to some of the typical American 1886. | NEW YORK ACADEMY OF SCIENCES. 37 earthquakes :—to those of 1602 and 1791, central in the St. Lawrence valley, in the first of which the shocks continued for months over an area of three hundred leagues; and to a number of those on the west coast of South America so destructive in Peru and Chili, and frequently accompanied by volcanic activity, at points both near and remote in the Andean chain. The earthquake of 1811, known as that of New Madrid, was most violent in the Mississippi valley. It was followed by shocks at short intervals until March, 1812, when one of great severity destroyed the city of Caraccas, in Venezuela. Accepting the nebular hypothesis, the evidence points to an earth crust from twenty to fifty miles thick, resting upon the plastic, semifluid contents of the interior. Volcanoes are the vents of this interior. Where earthquakes occur in the volcanic regions of Southern Italy, of Java, of the Moluccas, and of the region of the Andes, as the greater number do, they seem to have an intimate association with the volcanoes. The quantities of matter sud- denly ejected from these volcanoes, attended by explosions and the conversion of masses of water into superheated steam, must create cavities of the fluid contents, into which the flexible crust settles by gravity or pressure, causing surface elevations and de- pressions. Mere shrinking by cooling would not produce rugged mountain chains of their present form. Combined with these dynamic forces, more active in earlier cosmic ages, they were quite adequate to elevate the Andes or the Himalayas. All the phenomena of earthquakes in volcanic regions indicate their deep-seated origin and their connection with disturbances of the fluid interior of the earth. There was another group of earthquakes which occurred in regions of slight or no volcanic activity, some of them too re- mote from volcanoes to have any connection with them. If at- tended by volcanic eruptions, these never preceded, and always ceased with the convulsions. Yet they were gigantic in their phenomena—terrible in their devastating effects. What and whence was their origin? Were they due to the expansive force of vapors in subterranean cavities; to a slipping of sections of the earth crust upon each other; or to forces within the crust itself, and not more than 10,000 or 20,000 feet from its exterior surface? 38 TRANSACTIONS OF THE [Nov. 1, These earthquakes usually, it might almost be said always, occurred or were most severe in the deltas of great rivers or in such proximity to them as to point to some association of such rivers with their origin. Such were the earthquakes of Cutch at the mouth of the Indus, of Lisbon at the outlet of the Tagus of of 1662 and 1791, in the gulf of St. Lawrence, of New Madrid in 1811 in the valley of the Mississippi. Even those of Chili were most destructive at river-mouths, like that of 1837 de- scribed by Darwin, which destroyed Concepcion in the valley of the Biobio River. It might even be possible to include in the group the so-called Charleston earthquake of 1886. To learn what happens at the outlet of a great system of river drainage, we could have no better example than the Mississippi. With its branches it is the longest, its tributaries are the most numerous and the largest, and it drains the greatest area of any upon the earth. If the computations of engineers are reliable, it has in the past deposited a delta which commences above the Ohio River, has a superficial area of 13,600 square miles and an average depth of five hundred and twenty-eight feet. Hvery year it gathers up its burden from a vast plain, transports one thousand miles southward and deposits in the regular basin, called the gulf, 3,702,758,400 cubic feet of solid matter. At thirteen eubic feet to the ton, the annual tonnage of this carrier by water is 284,827,569 tons. Such a weight added year by year, principally deposited around and not far from the outlet, must in time become too great to be sustained by the earth crust beneath and the crust must give way. When it does, there will be a-depression into the fluid below, which must be compensated by an elevation elsewhere. If the subsidence is gradual, there may be no surface disturb- ance. But the crust is not homogeneous, is more rigid and less flexible in some places than in others. Suppose it resists the pressure in some places and yields to it in others for a time, and then at the weakest point suddenly gives way. ‘That point may be anywhere within a circle large enough to include Charleston. Wherever it is, there will be a sudden disturbance of levels, not only on the surface, but in the interior contents. It will give birth to an earthquake wave which, once set in motion, will, like 1886. ] NEW YORK ACADEMY OF SCIENCES. 39 all waves in fluids, be followed by others of less magnitude, until the levels are all adjusted and the equilibrium is perfectly re- stored. In conclusion, Mr. Chittenden maintained that the theory, that there was a class of earthquakes resulting from wave move~ ments of the fluid interior, accounted better than any other for the successive shocks of diminished force; it conformed to the evidence that true fissures extend through the crust, and that volcanic vents communicate directly with the interior contents; it was consistent with the inferred thickness and known flexi- bility of the crust, and accounted for the large area of surface sometimes involved. He did not contest the agency of shrink- age as a powerful factor of earthquakes; he presented these con- clusions of his own mind from an examination of the accessible evidence, that there was a class of earthquakes resulting from movemerts in the fluid contents below the earth crust, caused by changes on the surface due to river transportation. Dr. N. L. Brirron said he was informed that the series of posts placed along the New Jersey coast to show changes of level were not perceptibly changed by the recent earthquakes. Mr. H. T. WoonMan and the PRESIDENT also spoke. November 8, 1886. STATED MEETING. The President, Dr. J. 8S. NewBerry, in the chair. Fifty-four persons present. Mr. B. B. CHAMBERLIN exhibited pink dolomite from Mor- risania, found near the north end of the Madison avenue bridge. Mr. A. P. BJERREGAARD stated that he had analyzed it and regarded it as ferruginous dolomite or ankerite. Dr. J. J. FRIEDRICH exhibited muscovite from West 87th street, which was apparently folded and crushed as if by the yield- ing of the strata. Mr. Georee F. Kunz showed the cast of a diamond from North Carolina, which was probably the finest known from the 40 TRANSACTIONS OF THE [Nov. 15, United States. He also exhibited gold ornaments from the mounds of Orange Co., Florida. The metal was ninety-eight fine, and might have been obtained in North Carolina. One dise had a bullion value of sixty dollars; another was a casting. Or- naments of silver were also shown. Mr. Kunzalso referred to the discovery of fine pink spodumene at Andover, Maine; and a fine golden beryl at Litchfield, Conn. In reply to questions, Mr. Kunz said that the Cherokee gold ornaments were of low grade gold, averaging 400 to 600 fine, and many were plated. The PRESIDENT said that some of the ‘‘ plated” ornaments were produced by ‘‘pickling” in acids an alloy of gold and baser metals, and then burnishing the surface to leave there a layer of pure gold. Dr. Henry A. Morr read a paper on A LIMIT TO THE HEIGHT OF THE ATMOSPHERE. The subject was discussed by PRESIDENT NEWBERRY and Pror. W. P. TRowBRIDGE. November 15, 1886. STATED MEETING. The President, Dr. J. S. NEWBERRY, in the chair. Fifty-six persons present. Mr. CHITTENDEN, referring to the gold ornaments exhibited by Mr. Kunz at the previous meeting, suggested the possibility that the gold might have been obtained from a Spanish ship which was wrecked on the Florida coast in the year 1640, laden with a large amount of gold from Central America. Chroniclers had mentioned that some of the gold was in possession of the uatives of the coast. Dr. Cuarwes EK. PELLEW read a paper on RECENT INVESTIGATIONS ON THE MITIGATION OF PATHOGENIC BACTERIA. The subject was discussed by Mr. Luctus Pitkin, Pror. C. F. CHanpier, Mr. L. E. CHITTENDEN, and the PRESIDENT. 1886. ] NEW YORK ACADEMY OF SCIENCES. 41 November 22, 1886. STATED MEETING. The President, Dr. J. S. NEwBERRY, in the chair. Forty-one persons present. Mr. A. P. BJERREGAARD exhibited galena from shaft 22 of the new aqueduct, Fordham Heights; and the PRESIDENT re- marked upon the occurrence and origin of the mineral. The SEcRETARY spoke of the discovery by Prof. Branner, of Indiana, as announced in the November number of the American Journal of Science, of undoubted glacial striz upon the summit of Elk Mountain, the highest point in Northern Pennsylvania, it being 2,700 feet above tide. The thickness of the ice-sheet of the Glacial Epoch was dis- cussed by the PRESIDENT; also its work and the evidences of more than one ice period. He referred to the recent discovery in India of supposed glaciated boulders in clay slates, which lie at the base of tertiary strata, and the added force which this dis- covery gives to the theory of cosmic causes of the climatic changes. Pror. D. 8. Martin thought that in deposits of ice periods due to astronomical causes could be found a key to the length of geologic time. The subject of the peculiarities and amount of glacial erosion was discussed at length by Mr. L. E. CoirrenpeEn, Mr. F. J. H. MERRILL, and the PRESIDENT. Pror. D. S. MARTIN in behalf of a special committee read a memorial sketch of Axe. Rutus Mrinrce. November 29, 1886. STATED MEETING. The President, Dr. J. S. NEWBERRY, in the chair. Thirty-seven persons present. Mr. J. J. FrrepRicu exhibited malachite, with its associated minerals, from 117th street, between Fourth and Madison 42 TRANSACTIONS OF THE [Nov. 29, avenues, also quartzite containing a large proportion of dissemi- nated tourmaline. Mr. L. E. Currrennen stated that he had found proof in old records that the Natchez Indians smelted the gold of Georgia. Mr. P. H. Dup ey showed a fine instantaneous photograph of a railway train moving at the rate of forty-eight miles an hour. Pror. ALBERT R. LEEDs read a paper on THE AMERICAN SYSTEM OF PURIFICATION OF THE WATER SUPPLIES OF CITIES. Acting under instructions from the Aqueduct Boards of New- ark and Jersey City, I spent the past summer in examining the water supplies of the large cities in England and Scotland. Many of these cities have already passed through crises in the history of their water supplies, similar to those at present agi- tating American communities. It is of systems of purification which they have adopted, and of a quite different American system designed to meet the different requirements of climate, character of water supplies, labor and capital in our own country, that I propose to speak this evening. Our modern manufacturing towns increase in population with such rapidity that they soon find their local sources of water supply insufficient in quantity, and dangerous to health from pollution by sewage and factory waste. ‘Then follows a more or less prolonged period of bitter controversy. It matters not how plain the fact of gross pollution may be, the fact is denied. In case the chemical testimony agrees with that of the senses, and water which is dirty, foul-smelling, and bad-tasting is found by the chemist to be impure, his honesty and ability are assailed. Either his results are declared false, or it is as- serted that they mean just the reverse of what he himself says. Other experts are employed, and the local water supply, though it may contain the sewage of ten or a hundred thousand people, like that of Albany, Newark, Jersey City, and Philadelphia, is joyfully discovered to be extremely wholesome, and second in purity to none inthe country. But atlast, after years of denial, during which the public health has severely suffered, the fact of pollution is admitted, and the community resorts to one or more of the three following remedies: 1st. It abandons local for remote sources, such as springs, lakes, rivers, or areas of upland drainage. 2d. It sinks artesian wells, or deep wells, or subterranean gal- leries. 1886. | NEW YORK ACADEMY OF SCIENCES. 43 3d. It purifies the polluted local supply. In the study of this subject, there is no source of information more valuable than the blue books containing the minutes of inquiry before the Royal Commissions of 1851 and 1868 upon the supply of London. It is there stated that at first London drew its supply directly from the Thames where it flowed through the town, at London Bridge. This was in 1581, and a century later (1691) the Thames was again drawn upon at Char- ing Cross, and this intake remained in use as late as 1829. Again, in 1723, the Chelsea water works were established, and in 1785 those at Lambeth. Whilst some part of the water sup- ply was derived from springs in the chalk formation at Chadwell (brought in. through a canal called the New River, in 1613), and another part from the river Lee (introduced by the East London Water Works Co. in 1806), yet as late as the year 1829, the metropolis was principally supplied by water taken from the Thames within the reach of the tidal flow. But in 1829, a Royal Commission, consisting of Telford, Brande and Roget, was appointed to inquire into ‘‘the description, the quality, and the salubrity” of the water. They reported ‘‘ that the Thames water, when free from extraneous substances, was in a state of considerable purity; but as it approached the metropolis it became loaded with a quantity of filth which rendered it disgusting. It appeared, however, that a very considerable part, if not the whole, of this extraneous matter might be removed by fil- tration through sand, and the Commission decided that it was perfectly possible to filter the whole supply with the requisite rapidity and within reasonable limits of expense.” Stimulated by this report, and alarmed probably at the prospect of a sweeping change of the sources of supply, the companies directed their attention to the purification of the water by fil- tration. It was soon found that the only appropriate material for mechanical filtration on a large scale, was fine sand; but the great practical difficulty was to prevent the sand from becoming clogged, and to find an easy, practical, and cheap method for its renewal. After long experimentation, a means was discovered of getting over these difficulties. It was found that by far the greater quantity of the impurities was held in suspension by the agitation and motion of the water, and that, if it was allowed to stand for some time at perfect rest, in a reservoir, the heavier and grosser particles were deposited by simple subsidence, leav- ing only a small proportion of lighter and finer matters to be dealt with by filtration. It was also found that when the water was allowed to filter downwards through a porous bed of sand, held up in its place by underlying layers of coarse gravel, the dirt did not penetrate into its mass, but was stopped at its 44 TRANSACTIONS OF THE [Nov. 29, upper surface, so that the whole cleaning operation necessary was to scrape this surface off to a slight thickness, and, when it had become too much diminished, to put on fresh sand. In accordance with these suggestions, the first large filter, which had an area of one acre, was put into use by the Chelsea Co. in 1829.* It worked well, so well indeed that it led to the well-nigh universal practice of filtration in England. Our failure to do the same in this country shows that in this re- spect we are behind the age. But about the time of this first use of filters in England, the disturbing ideas of modern sanitary science took their rise; that unspeakable abomination, the domestic cesspool attached to a city house, began to be abolished; drainage and sewerage works were established, and the amount of impurities carried to and fro under London Bridge was increased enormously. This agitation kept on growing until, in the year 1534, the engineer, Mr. Telford, recommended that the Thames should be abandoned. This was not done, but in 1851 a Royal Commis- sion, consisting of Profs. Graham, Miller, and Hoffman, recom- mended that while the supply should still be drawn from the Thames, the points of intake should be removed above the influ- ence of tidal flow (7. e., above Teddington lock). They made other recommendations which were incorporated into an Act passed in 1852, regulating the water supply of the metropolis. In this act the two clauses of greatest significance to us are, first : That every storage reservoir within five miles of St. Paul’s should be covered ; and, secondly, That all water supplies for domestic use should be effectually filtered, unless it is pumped Srom wells direct into covered reservoirs. A mere statement of the law which was passed after a quarter of a century of discussion by the most eminent engineers, chem- ists, and law-makers of England, is a more emphatic testimony to the fundamental importance of the provisions therein con- tained than any argument I am able to make. This law led to certain results throughout England, which I trust will become universal. These are: 1st. The education of public opinion to such a point as to de- mand sources of city water supply, actually and visibly free from pollution. The wealthiest communities, like Glasgow, Man- chester, and Liverpool, have deemed it a wise investment of great sums of money to obtain sources absolutely free from sus- picion and reproach. 2d. The construction of large, and in some cases vast, reser- voirs with the object, not merely of safety, but also of allowing * Royal Comm. Water Supply, 1868. 1886. | NEW YORK ACADEMY OF SCIENCES. 45, opportunity for the dissolved organic matters to oxidize, and to be carried by subsidence along with the suspended mineral mat- ters to the bottom. 3d. Effectual filtration. And it should be noted that, when the act of 1851 required the London companies to filter the water, under very heavy penalties, the water referred to was that taken from the Thames above Teddington lock, which water the Commission had previously found to be ‘‘ perfectly wholesome, palatable and agreeable.” Still more striking instances of the esti- mate put upon filtration, as a process indispensable to the excel- lence of city water supply, were frequently brought under my personal observation, and some I| shall mention later. 4th. The preservation of the water, after it has been filtered, in covered storage reservoirs. The good effects of the act of 1851 speedily became apparent. The water companies expended 2,500,000 pounds, with the re- sult, according to the examinations of Prof. Hoffman and Mr. Blyth made in 1856, of bringing about ‘‘ a very positive and con- siderable diminution in the amount of organic matter. This, though doubtless due chiefly to the removal of the intake above the tideway of the Thames, was also attributed in great degree to the considerable improvement which had taken place in the collection, filtration, and general management of the supply of water.” But, fortunately, the public was not satisfied. In pursuance of the recommendations of the Royal Commission of 1865, on the pollution of rivers, the admission of sewage or any other offensive or injurious matter into the Thames, or into any tribu- tary, stream, or water course within three miles of its junction with the Thames, was declared illegal, with heavy penalties. In 1866, 5,596 lives were destroyed in London by cholera, and al- though this visitation was subsequently attributed to the polluted water of the Ravensbourne and the foul unfiltered water from the reservoirs at Old Ford on the river Lee, yet it so alarmed the community that the Commission of 1866 was appointed to make a far more extended inquiry than ever before, and to ascer- tain what supply of unpolluted and wholesome water could be obtained, by collecting and storing water in the high grounds of England and Wales, either by the aid of natural lakes or by artifi- cial reservoirs, at a sufficient elevation for the supply of London and the principal towns of England. Nowit isa well-known fact that the recommendations of the very distinguished engineers came to naught, so far as London was concerned, though they are at present bearing fruit in connection with Manchester and Liverpool. It is well worth our while to inquire why such was the case. 46 TRANSACTIONS OF THE [Nov. 29, Mr. Bateman’s plan was to bring the waters collected from the drainage areas at the head of the river Severn in Wales (inclua- ing the drainage area of the Vyrnwy) by gravitation through an aqueduct 180 miles in length, and capable of conveying 230,- 000,000 gallons per diem. Messrs. Hemans and Hassard pro- posed to bring the waters of lakes Thirlmere, Ullswater, and Haweswater through conduits, tunnels, and pipes equivalent in their carrying capacity toa river 30 feet wide and 10 feet deep, over a length of 270 miles. These plans, which were considered the best, were reported upon unfavorably, principally on account of the cost, the estimated expense of Mr. Bateman’s scheme being 55,000,000 pounds, and that of the Cumberland Lake scheme still greater. This report decided the future supply of the metropolis and confined it to local sources. The supply from Lake Thirlmere has already been appropriated by the city of Manchester. The water will be brought in a tunnel nine feet square to the reser- voirs at Prestwich on one side of Manchester, a distance of 95 miles, and continued thence to reservoirs on the other side of Manchester, a distance of 110 miles. Mr. Hill, the engineer of the new supply, informed me that the first ten million gallons are estimated to cost two million pounds, inasmuch as the tun- nels of full size are to be constructed at once, and connected by a forty-inch iron pipe where siphons are necessary. The second ten million gallons are estimated to cost only 400,000 pounds. The land damages to persons living around the lake and along the tunnel are 225,000 pounds. The supply from Vyrnwy Lake has been appropriated by Liver- pool. This artificial lake is to be created by a dam which at its top will have a length of 1,173 feet, and will rise to a height of of 144 feet above the bed rock and 84 feet above the bed of the existing river. Its length will be four miles and three-quarters, its area 1,165 acres, and its greatest depth of water about 84 feet. The aqueduct from the lake to the existing Prescot reser- voir, 9 miles east of the Liverpool Town Hall, is 68 miles. It will consist mainly of tunnels through which the ultimate supply of 40,000,000 gallons a day may be passed without filling them, and of three lines of pipes each having an internal diameter vary- ing according to the fall of the sections from 39 to 42 inches. All this very poor water from the Welsh mountains will be subjected to jiltration through sand-filters, the Oswestry reservoir and the three reservoirs for filtered water having an aggregate storage capacity of 54,540,500 gallons. In one very important particular the Commission of 1866 was certainly in error. It thought a probable increase of population to 4,500,000 or 5,000,000 would have to be provided for, and a 1886. | NEW YORK ACADEMY OF SCIENCES. AY maximum daily supply of 200,000,000 gallons, though the time for such an extended provision would be very remote. Asa mat- ter of fact, the population supplied by the companies in May of this year was 5,274,542, and the average daily supply during the month was 160,388,316 gallons. Of this more than half, or 82,366,466 gallons, came from the Thames, and the balance from the river Lee, and from certain chalk springs in the valleys of the Lee and Thames, and from 21 deep wells sunk into the chalk formation to the north and south of London. There are 44 sud- siding reservoirs for untiltered water, with an area of 465 acres, and an available capacity of 1,290,100,000 gallons, and 53 covered reservoirs for storage of the water after filtration with a capacity of 160,002,000 gallons. The number of filter beds is 99, with an area of 98 acres. Of this surface, 92 acres were cleansed during the month of May, some of the filter beds being cleansed once and partly gone over again during the month. The maximum permissible rate of filtration is two feet per hour and per square foot of surface, but asa matter of fact the actual rate in the month of May last was generally much smaller than this, some filters passing only 14 feet. The construction of the filters varies greatly, the top layer, however, being in all cases fine sand, in depth from 2 to 43 feet. From the published analyses it appears that the quality of the water supplied to London is usually satisfactory, though at times results are obtained adverse to that portion of it which is derived from the Thames. ‘The population of the drainage area of the Thames is very large, and although the towns located therein are compelled to purify their sewage, yet much polluting material from them and from the floating population on the river finds its way into the river. Though the importance, and in many places the necessity, of purifying our water supplies by artificial methods have been well recognized, yet the great first cost of construction of the English system of filter-beds, the number of laborers required to keep them in efficient action, and their failure to satisfy all the requirements which are essential to an entirely satisfactory system of water purification has prevented their coming into use in this country. There has grown up, by the labors of our own chemists and engineers, a system which is designed to meet our pe- culiar needs, and which may be most conveniently and accurately designated asthe AMERICAN SYSTEM OF WATER PURIFICATION. It comprises three distinct features: 1. Artificial aération under pressure. 2. Precipitation of dirt, sewage, hardening constituents, and eee by harmless precipitants: 7. ¢., assisted precipi- ation. 48 TRANSACTIONS OF THE [ NOV. 29, 3. Mechanical filtration through filters capable of rapid re- versal of current, and cleansing by mechanical means. ARTIFICIAL A ERATION. One of the easiest and most inexpensive methods of improy- ing the quality of water is by means of artificial aération. The importance of natural aération has been recognized from time immemorial, and the effect of tumbling down natural falls and rapids, passing over artificial dams, and of agitation by winds and storms, in keeping water lively and sweet, is too well known to need more than passing mention. It is of especial interest to us that this mode of improving water was first applied to city water supply in consequence of the extremely offensive taste and odor of the Schuylkill water in January and February, 1883. The fact that the analyses revealed the presence of a large amount of sewage in the Fairmount water did not explain its peculiar offensiveness at that season, for there have been times, before and since, when it contained even more sewage and was not so unpalatable. But it appeared to me very noteworthy that the oxygen which ought to be present in a state of solution was largely deficient. Much of it had been used up in the oxidation of the sewage, and the river, being ice-bound from its source to Fairmount Dam, had no opportunity of taking from the atmosphere sufficient oxygen to replace that which had been lost. Reflecting upon these facts, I thought it worth while to try the effect of submitting the disgusting samples from Fairmount Pool to artificial aération. I found that they not only took up from the air forced to them the oxygen they lacked, but also that much of the sewage to which their offensiveness was due was destroyed. These experiments suggested to me the idea of pumping air into the lower ends of the mains at the pumping- stations. This way of introducing the air was not only the easiest and simplest, but it also afforded an opportunity of placing the mixture of air and water under a maximum pressure. Air, as is well known, consists of twenty-one parts by volume of oxygen and seventy-nine parts of nitrogen; but the oxygen is more soluble in water than the nitrogen, and therefore the greater the pressure to which a mixture of air and water is sub- jected, the larger is the relative amount of oxygen made to enter into solution. The study of the subject received fresh impetus from the con- dition of the water supply of Hoboken in the latter part of July, 1884. At that time, the oxygen, in a number of samples from the Hackensack River, whence the supply of Hoboken is derived, fell to 3.87 c.c. per litre, and the total dissolved gases to 14.93 c.c. Contemporaneously, the same waters, when im- 1886. | NEW YORK ACADEMY OF SCIENCES. 49 pounded in the reservoir, became covered with a scum several inches in thickness, consisting largely of Oscillarie. These quickly died, and yielded up a dark-blue coloring-matter (the Phococyan of Cohn). Finally, this great accumulation of vege- table growth passed into a state of active decomposition, at- tended with the formation of white foam, and the liberation of large volumes of carbonic acid and other gases. The water, for ten days previous, had been too nauseous to drink, but the whole succession of phenomena above described took place within twenty-four hours, the vast development of algwe, their breaking- up with evolution of green and blue coloring-matter, and their final decomposition occurring with astonishing rapidity. The entire reservoir had the appearance of an enormous dying vat, covered with dark-green and blue dye-stuffs. A repetition of the same disastrous sequence of events was threatened on September 14th, when the percentage of dissolved oxygen fell to 4.¢.c., and at the same time a growth of alge began in the reservoir. But meanwhile arrangements had been perfected in anticipation of this catastrophe, and by pumping air under pressure into the mains, the percentage of total dis- solved gases was raised from 15.9 c.c. to 21.2 c.c. The green scum on the reservoir disappeared, and the taste and smell of the drinking-water became satisfactory. In November, 1884, a preliminary experiment was instituted at the Fairmount Pumping Station of Philadelphia, an air pump be- ing attached to the main at that point. The aérated water was pumped into the Corinthian Basin through the forty-eight-inch main, a distance of three thousand feet. The results of this ex- periment were so encouraging, that the chief engineer, Col. Lud- low, obtained air-compressors for all the pumping-stations. At only one of them, however, has the process been applied, namely, at Belmont, the other mains being too leaky to permit of its being used. At this station the water has been charged with twenty per cent of its volume of air, and the change in composition thereby effected is strikingly illustrated in the following results, which give the composition of the water before it enters the pumping- main and as it is discharged therefrom: Parts per 100,000. es aT eae: Non-aérated. Aérated. Free Ammonia, 0.017 0.004 Albuminoid Ammonia, 0.011 0.007 Oxygen required to oxidize organic substances, 0.133 0.117 Nitrous Acid, 0.0008 none 50 TRANSACTIONS OF THE [Nov. 29, Nitric Acid, 0.45 0.54 Total Solids, 9.00 8.70 It will be seen that the albuminoid ammonia has diminished nearly forty per cent; and, what is the most noteworthy feature of all, the nitrous acid has undergone complete oxidation, none being present in the aérated sample. At the same time, by oxi- dation of the nitrogenous portions of the organic matter, the nitric acid has been increased twenty per cent; and by oxidation of the organic constituents in general, the total solids have been diminished from 9 parts per 100,000 to 8.7 parts. The process has now been applied to the entire water-supply of Hoboken, amounting to four million gallons per diem, for more than two years, and during this time the unpleasant taste which caused its first application has never reappeared. A similar experience in Brooklyn has caused the process to be used in connection with the water obtained from driven wells. This driven-well water has been used in the Greenwood Cemetery to feed a number of artificial lakes arranged to beautify the grounds. Last summer I was asked to examine the water in the reservoir into which the driven-well water is first pumped, and to devise a means, if possible, for preventing the enormous growth of plants therein. The growth, on examination, proved to be diatomacee, particularly of the species Navicula viridis, and the green vegetable substance which by its decay rendered the water offensive was the slime secreted by these diatoms. Two facts were prominent. ‘The one was that the diatoms could be made to grow very rapidly when exposed in open jars to sun- light; the other, that the water of the reservoir was very deficient in dissolved oxygen. It contained only 2.32 cubic centimetres of oxygen in the litre, and the enormous amount of 4.97 cubic centimetres of carbonic acid. LIadvised the covering of the reservoirs to exclude sunlight. The authorities were opposed to so doing, because it destroyed the very result aimed at in provid- ing the reservoir and ponds, which was to beautify the park. Then I advised the use of an air-compressor. ‘This was installed, and the result is given in the following letter from the consulting engineer: NOVEMBER 27TH, 1886. Dr. Albert R. Leeds. DEAR Srr:—In answer to your inquiry concerning the trouble at the Greenwood Cemetery reservoir, I would state: that the water, fresh from driven wells, when delivered into the reservoir began to develop decaying vegetation, which, in a short time, rendered the water offensive to taste and smell; that immedi- ately on receipt of your report and recommendation last June, I set up an ordinary compressor, and pumped air into the mains 1886. | NEW YORK ACADEMY OF SCIENCES, dL under a pressure of about eighty pounds to the square inch, allowing it to escape through the reservoir, with this result: At first there was no perceptible effect, but upon increasing the amount of air supplied to the water, to the extent of about ten per cent of the free air to an equal volume of water, the trouble in the reservoir disappeared. Since that time, air bas been freely supplied whenever there appeared to be any recurrence of the growth of vegetation in the reservoir, and there has been no re- turn of the offensive taste and smell. Respectfully submitted, Cuas. B. BrusH, Con. Eng. Greenwood Cemetery. Similar troubles, and the development of a variety of odors chronicled as ‘‘ fishy,” ‘‘ pig-pen,” ‘“‘cucumber,” and the like, have been reported as affecting, at one time or another, the water supplies of most of our towns. There is good reason to suppose that these complaints will continue as long as water which, on standing, has lost most of its dissolved oxygen and has become stagnant, is exposed to our burning suns, and allowed to rise to a temperature of 70° and upwards, in uncovered reser- voirs. Hither it should be covered, so as to exclude light, and kept cool, or, if its temperature is allowed to rise above 70° and it is exposed to the sun, it should be charged with air and kept moving. Jn our own country, prevention of stagnation by adopting the latter method has proven more economical and effi- cient than the covering of the reservoirs. Before leaving this part of the subject, I shall state that when I introduced the use of compressed air for water purification, I did not do so for the reason that the air brought about a direct chemical oxidation or burning up of the organic impurities. In my various reports to the Water Department of Philadelphia, relative to the new water supply of that city (volumes for the year 1883, 1884, and 1885), and also to the Special Water Com- mission, appointed by the State of New York (1885), charged with proyiding a new water supply for the city of Albany, I have advocated the use of air under pressure for other reasons. They were :—1st, Because the disagreeable taste and odor in unpotable water are frequently due to gaseous and volatile im- purities, which can be largely swept ont of the water by the use of an excess of air acting mechanically as a deodorizer and dis- infectant, thereby exerting a sweetening action in the manner of a water-scrubber ; 2d, because the chemical and biological analyses contained in these reports show that where sewerage is being broken down, it is in presence of large numbers of bacteria, which grow and multiply upon a pabulum of sewage. Through the agency of the vital processes of bacteria, oxygen is rapidly absorbed and carried to the decomposing sewage which is broken 52 TRANSACTIONS OF THE [NOv. 29, up into nitrites, nitrates, carbon dioxide, and other partially or wholly oxidized compounds. Asa result, where the amount of incoming sewage is large, the number of microbes is great, and so likewise the quantities of the oxidized products of decomposi- tion, the nitrates and carbon dioxide especially. At the same time, the oxygen which should always be present in notable quantity in good water, was shown to have undergone a process of exhaustion, and to have fallen below its normal amount. When we replace the oxygen so absorbed, we supply the bacteria with something essential to their beneficent labors, and without which a portion of the sewage remains unoxidized. After the work of these oxygen-absorbing microbes is completed, they either perish or remain as resting spores, and then they should be removed together with the products of their labors by filtration. ASSISTED PRECIPITATION. Recourse is had to this process under the following conditions : Ist. When the particles of clay and other suspended matters are so minute that they pass through the pores of a filter with- out being arrested. 2d. When lime, magnesia, and other salts are present in such large amounts that the water is hard, rendering it unfit for laundry use, and making scale in boilers. 3d. When the water is discolored, and more especially when the discoloration is the dark yellow stain due to peaty matters. After trials upon a great number of substances, sulphate of alumina has been found to be the best precipitant for substances of the first and third class. It throws down both the suspended matters and the peaty coloring substances by forming with them an insoluble coagulum. ‘The alumina salt is decomposed into a basic aluminic sulphate which, being itself insoluble, is precipi- tated at the same time, and is filtered out along with the sub- stances it has united with and thrown down, 70 alumina remain- ing in the water. The action of clay, which is the hydrated silicate of alumina, in purifying drinking waters is well known, the clay having a strong affinity for organic coloring matters and the ammoniacal and albuminoid substances arising from the putrescent decomposition of animal and vegetable substances. But precipitation and clarification by the hydrated silicate of alumina is too slow for mechanical purification, and the sulphate must be employed, or the double sulphate of alumina and am- monia, which iscommon alum. ‘The amount of alum requisite is extremely small, one grain to the gallon being ordinarily sufficient. It communicates no taste to the water, nor does it have any effect upon the digestion or health of the persons using . 1886. | NEW YORK ACADEMY OF SCIENCES. 53 such aluminated water. On the contrary, its use, under the circumstances mentioned, is highly beneficial. It removes the insoluble alumina compounds originally present in the water. The insoluble coagulum or clot thus formed carries down with it the products of putrescent decomposition, which are always present in natural waters, except such as come from deep-seated sources like wells and springs. And at the same time there are precipitated in this coagulum the microbes, or so-called disease germs. In fact, there is no process so practical and effectual for removing these germs and putrescences as the use of alum in small quantities followed by filtration. Long-continued boiling destroys them, but it is costly and impracticable. It renders the water bad-tasting, destroys its liveliness by expelling the dis- solved gases, and makes the water unfit for domestic use. Freezing leaves much of the organic matters in the water, de- stroys only a portion of the germs, and is impracticable. But by the use of the above means, river waters which were originally yellow and turbid from the presence of mud and finely divided silt, and disgusting from sewage and organic filth, have been rendered clear, safe, and palatable. For softening hard water, the precipitant used is lime, the lime carbonate thrown down being removed by filtration. sti- mating the hardness in degrees, and taking one degree as _ that equivalent to the hardening produced by one grain of lime car- bonate dissolved in one gallon of water, the hardness has been suc- cessfully reduced from twenty-six degrees to three degrees, or from very hard to soft water. Not only is the water thereby rendered fit for use in boilers and in washing, but it is more wholesome. Soft water in itself is more wholesome than hard, and moreover, in the process of softening in this manner, the coagulum of lime carbonate carries down with it the micro-organisms of disease. In the way of overcoming difficulties this result, striking as it is, is not so significant to the chemist as the removal of the deep coffee-colored dye imparted to the water by juniper swamps. I give here the analysis of such a water from a southern swamp, which by the use of alum and lime, and subsequent filtration, was changed from a deep yellow, peaty tasting and boiler corrod- ing water, to a perfectly colorless, limpid, sweet water. COMPOSITION OF WATER FROM JUNIPER SWAMPS. Parts PER 100,000. Free ammonia, 0.0095 Albuminoid ammonia, 0.0335 Oxygen required to oxidize organic substances, 4.05 54 TRANSACTIONS OF THE [Nov. 29, Oxygen required to discharge the peaty color, 3.30 Nitric anhydride, 0.231 Chlorine, 0.406 Total hardness, 3.5 Total solid residue at 110° C, 11.20 Volatile matter at red heat, 10.25 Fixed mineral matter, 0.95 The oxygen gus dissolved in one litre was 5.17 cubic centi- metres, the carbon dioxide 5.27 cubic centimetres, and the sum of the dissolved gases 25.90 cubic centimetres. It will be seen at once that the change of such a dark yellow fluid to a colorless sweet water was essential to rendering it potable. MECHANICAL FILTRATION. Up to the present time no material has been found which is practically available for filtration on a large scale except fine sand. Sponge, coke, animal and wood charcoal, porous brick, carbide of iron, spongy iron, and many other materials have been tried, but with the result as above stated. When metallic iron is used, excellent results are obtained through its chemical action as a carrier of oxygen to the organic matters, which are thereby oxidized and destroyed, but the water even then must be subsequently filtered through sand. Until quite recently it has been supposed that the main bene- fit of sand filtration is in the removal of suspended mud and dirt, the amount of organic impurities thereby removed being small. But since Pasteur discovered that the micro-organisms, which are now held to be the specific germs of disease, may be completely arrested by filtration through a thin porous plate, a great revolution of opinion has been effected. In his report for the month of May last, Dr. Frankland states that the unfiltered Thames water yielded by the method of gelatine- peptone culture, 4,800 colonies of microbes per cubic centimetre of water. After passage through sand filters at Chelsea, it yielded only 59 colonies, and through those of West Middlesex only 19 colonies. This is indeed astonishing, and the more so when the remarkably pure water in the deep chalk;wells of Kent yielded 8 colonies, and the same water by the time it reached its point of supply had increased in its number of micro-organisms, until 101 colonies were obtained in the culture liquid. At the present time, American engineers regard tt as impracti- cable to introduce the English system of sand-filters, on account of the great expense of operating them. ‘This has been variously estimated atfrom $2.50 to $5.00 per day for each million gallons TRANSACTIONS p rue NEW York ACADEMY OF SCIENCES, [Facing page 55, NS OF 1886. | NEW YORK ACADEMY OF SCIENCES. dd filtered, exclusive of first cost and interest. Such being the case, I need not go into a statement of the reasons why the few which have been actually brought into use in this country: have been so little successful. The conviction appears to be generally entertained that American ingenuity has discovered a method by which mechanical arrangements have taken the place of the cumbrous English system, and done away with the manual labor required in cleansing. Many contrivances have been brought forward, but they are crude, or have complicated systems of pipes for reversals of the current, or are wasteful in the use of filtered water for cleansing. Recently, however, an extremely simple device has been proposed, which is yield- ing excellent results. As is well known, the efficient part of a filter-bed is the top layer of sand, which need not be more than two feet in thickness. At Poughkeepsie, on the Hudson River, {not in successful operation) this two feet of sand rests on four feet of gravel and stone which are provided merely to support the sand and to afford channels for the filtered water to drain away. ‘This gravel and stone are replaced in the mechanical filter used in the American system of water purification, by perforated double pipes. The construction of this filter, called the National Filter, can be readily understood from the accompanying wood-cuts. The water enters the filter at A, passes down through the bed of sand, and out through the perforated double pipes at G in the bottom of the filter. These pipes permit the filtered water to flow out. freely, but prevent the escape of any of the sand with it. This filter has another device which is different from the English system, and is an entirely novel one. It is intended to thoroughly cleanse the upper sur- face of the filter-bed by means of surface washing. The dirt and filth are deposited at the surface of the bed, and these are swept off by a reverse current sent through the valve OC, and the washing pipe F, and escaping at the top of the filter through the waste-pipe B. In the English filter-bed, the dirt is lodged on the surface, very little being carried below. The operation of cleansing is therefore that of shoveling off as thin a layer at the top as can be taken off by a shovel, washing this top layer in tanks, carting it back, distributing it over the surface, and then starting the operation of filtration over again. In the National Filter, this tedious work of cleansing, which in Eng- land is all carried on by manual labor, is performed by a reverse current. In the course of five minutes’ time, the surface is cleansed from the impurities lodged upon it during as many hours of filtering very dirty water. Since the filter is worked under pressure, a greater thickness of the sand is compelled to do duty as the filtering medium, and the longer the time the 56 TRANSACTIONS OF THE [NOvV. 29, filter is operated without starting the reverse current, the greater the depth to which the dirt penetrates. As a general rule, however, the dirt is retained within the first six inches, unless the filter is run for longer than twenty-four hours without . cleansing, and since the upper pipes for cleaning are placed a foot below the surface of the bed, the rapid washing of this foot of sand when the reverse current is sent through it cleanses the filter thoroughly. The tendency is for the water to gradually form channels through the entire body of the filter-bed. For this reason, the bed is mechanically made over again and, as it were, renewed, by calling into play the lower series of double perforated pipes. After first cleansing the swrface, in the man- ner just described, by the surface pipes, the reverse current is made to passthrough the lower pipes. Every portion of the bed is floated loose, and by the attrition of one particle of sand against another the impurities are scrubbed off, floated to the top, and carried off through the valve B. When the cleansing is complete, which is shown by the pipe B delivering bright, clear water, the reverse current is shut off, and the filtering material settles down once more into a new uniform filter-bed. The arrangements for aérating and filtering are shown in the annexed cut. The three filters are each 10 feet in diameter, and each capable of filtering 350,000 gallons per diem. 425 bushels of filtering material are required for each filter. The water passes in through the pipe D, and the filtered water out through the pipe G. The air is driven in under the amount of pressure required, and in the quantity requisite to bring the percentage of dissolved oxygen to a maximum, through the pipe C. The air-compressor is represented at the left of the drawing, and may be made to deliver either a very large amount or a very small amount of air, as the water requires. The mechanical arrangements for adding the precipitants, which are required in some cases, are not shown. The precipitants are usually added before the introduction of the compressed air, though sometimes after. The nature and amount of the pre- cipitant, and the quantity of air required, is determined in each case by the character of the water as revealed by analysis. If it is a water whose only impurity is suspended matters, the filters alone are requisite. If, in addition to this, it is foul-smelling and tasting, and has lost the proportion of oxygen normally present in sweet waters, the aérator is attached to the filter. IEf it is hard, or filled with very minute suspended particles, or dyed with peat extract, etc., the precipitant of lime or alum or both is added. It is subsequently aérated or not, as the charac- ter of the water demands, and then both precipitant and pre- cipitate are removed by filtration. TRA * TE M OES. YOR: 'H T) I T. Ss. page 56. acing 1b Al 1886. | NEW YORK ACADEMY OF SCIENCES. 57 Mr. Lucius Pirk1n spoke as follows: In his closing remarks, Dr. Leeds has referred to filters in- tended for household filtration on a small scale. The import- ance of this branch of water purification may be better realized, when it is considered with what care the source of water supply for large cities is selected, as compared with the supply in the suburbs and country towns. Here purification on a large scale is impossible in the absence of a co-operation, which is hard to secure, and while doubtful water should be avoided, still cases are not uncommon where no recourse is possible except to sup- plies more or less suspicious. Proceeding on the germ theory of disease (now almost proven in its entirety), two methods of improvement for household use are prominent. The one by boiling the water kills the germs, the other by fil- tration seeks to remove them. The first method by driving out the dissolved air renders the water flat and insipid. The second method has in the past been the cause of nearly as much harm as good. It is only within the last few years that, with our increasing knowledge of the character of disease germs, ade- quate filtration devices have been introduced. A bit of sponge in a metal globe may entrap “rotifers” and ‘‘ entomostraca,” but disease germs with their minute dimensions may easily laugh it to scorn, or in its accumulated debris find a fit breeding ground. And here I would emphasize the necessity of frequent cleansing in all forms of filtration apparatus. The increased volume of flow of the clean surface over that clogged with or- ganic debris will, apart from sanitary considerations, repay the slight trouble incident to the cleaning. It has been my good fortune, during the past six months, to have made many and rigorous tests of the value of porous porce- lain in arresting the passage of bacteria contained in water. The porcelain tubes with which my experiments have been con- ducted, were of about one-tenth of an inch in thickness. It will be sufficient here to indicate briefly the result arrived at in my latest experiments on a set of four tubes. Under a pressure of about four feet, and with a continuous flow of water day and night, all of the tubes were delivering germ-free water at the 58 TRANSACTIONS OF THE [DEC. 6, end of five days (120 hours). Tests at the end of ten days (240 hours) showed two of the tubes delivering water free from germs. At the end of fifteen days one was still perfect in its ac- tion, and so continued for twenty days. ‘The water which was used in the trial was purposely fouled, containing about two thousand germs per cubic centimetre. The results obtained, then, with this material, are all that can be desired when cleaned say once in five days, if used under the conditions of the experi- ment. In the case of a substance like porous porcelain, it is a very easy matter simply to take it from its sheath, brush it off, and place it in boiling water for a couple of hours or, better still, in a hot oven. The porcelain is then in its original condi- tion, as far as regards efficiency. December 6, 1886. REGULAR BUSINESS MEETING. The President, Dr. J. S. NEWBERRY, in the Chair. Twenty-one persons present. The report of the Council was received and adopted, which recommended the payment of certain bills and the election of ALBERT A. Cary as Resident Member, and D. S. KeELuicort, of Buffalo, as Corresponding Member. The question of the adoption of the resolution offered by the Secretary, October 4th, 1886, making certain changes and addi- tions in the by-laws, was declared in order. The President read from a copy of the printed resolution, which had been sent to all the members. Items I., III., IV., and VI., as recorded in the Transactions of October 4th, 1886, were unanimously adopted. Item V. was unanimously adopted, with a change of the word ‘‘ Proceedings” to ‘‘ Practice.” Item II., increasing the amount of the fees and dues, was discussed and laid over one month; and a Committee, consisting of the President, the Secretary, and Messrs. Chittenden, Martin, and Trowbridge, was appointed to prepare and send to all the members a state- 1886. ] NEW YORK ACADEMY OF SCIENCES. 59 ment of the question, and of the need ofa larger income, with a request for the individual opinion of the members. Mr. H. T. Woopmawn announced the discovery of an ele- phant’s tooth, probably Zlephas Americanus, in the beds of silicified coral in Florida. The President described the char- acter, range, etc., of Hlephas and Mastodon. Mr. F. J. H. MERRILL read the following NOTE ON THE GREEN POND MOUNTAIN GROUP OF NEW JERSEY. The Green Pond Mountain series of rocks in northeastern New Jersey, which also extends through Orange County, New York, to the Hudson River and for some distance beyond, has heretofore been studied by geologists, since the time of Professor Henry D. Rogers, without positive determination of its age. Rogers believed the red conglomerate and sandstone which forms the base of the series, to be Triassic, and Mather surmised that it might be Oneida, while in the report of the Geological Survey of New Jersey for 1868, it was described as Potsdam. Recent investigations by the State Geological Survey have dis- covered evidence which fixes the horizon of the system. Dr. N. L. Britton has found that a fossiliferous limestone, formerly described as Trenton, is Lower Helderberg, and the speaker has discovered Oriskany and Corniferous fossils in a coarse white sandstone and conglomerate; so that there is repre- sented a continuous series of rocks from the red conglomerate, which is of Oneida age, and rests unconformably on the magne- sian limestone in places, to certain blue slates and grits which contain fossils, probably of Hamilton age, and which in New York State have yielded Psilophyton princeps, Dawson, and other Devonian plants. ‘The slates in the valley southwest of Greenwood Lake, which were formerly supposed to be of Hudson River age, are proved stratigraphically and paleontologically to belong to the Upper Devonian. (See Annual Report Geol. Survey of N. J., 1885). Mr. L. E, CHITTENDEN spoke as follows upon 60 TRANSACTIONS OF THE [DEC. 6, THE USE OF METALS BY THE ABORIGINES OF GEORGIA AND FLORIDA. At a recent meeting of the Academy, in some remarks upon the ornaments of mixed gold and silver, from Indian graves in Florida, presented by Mr. Kunz, I said that there was reason to believe that the gold and silver in possession of the Florida Indians had been taken from Spanish ships wrecked on that coast. A recent examination of the evidence on that subject has developed some facts which may interest the Academy. For more than half a century after the discovery by Colum- bus of the western hemisphere, only the eastern coast of Flor- ida was known, and that was supposed to be a part of the island of Cuba, as it is laid down on the celebrated wood-cut map by Holbein, in the ‘‘ Novus Orbis” of Gryneus, as late as 1555. Among the vessels there lost, was a large part of a fleet of thirty ships, including that on which the infamous Bovadilla, the per- secutor of Columbus, had embarked, and which was laden with gold and silver, despoiled from the Indians. Strict truth will possibly require some discount on this treasure, in the account of Peter Martyr, who says ‘‘ there were several pieces of 300 pounde weighte, and one of three thousand three hundred and tenne pounde, of eight ounces or pesos, albeit there were mo then a thousande persons which came and handled that peece of golde.” In the ‘‘ Histoire notable de la Floride,” by Basanier, Paris, 1586, occurs a passage translated as follows: ‘‘ There was found among the Indians a great quantity of gold and silver, which, as I learned from themselves, was from the ships which had been wrecked along the coast. They trade in it with one an- other. What confirms this statement is the fact, that along that part of the coast and the cape where the wrecks occur, there is more silver than there is farther north. They said constantly that in the Apallache mountains there were mines of copper which I think are really gold.” The closing observation of Basanier indicates that investiga- tions should be extended farther. There is little profit in search- ing the meagre records of the three first expeditions to Florida. That of Ponce de Leon, in 1512, was in search of the fountain of perpetual youth—those of Vasquez de Ayllon in 1522 and 1886. ] NEW YORK ACADEMY OF SCIENCES. 61 1524 were after slaves, when that Spanish wretch seized and carried to perish in the mines of Cuba two cargoes of Indians. That of Pamphilo de Narvaez was in 1527. Over the last we must pause for a moment to note the sad results of his incon- ceivable brutality and its swift punishment. He found the most peaceful, inoffensive, and civilized race of Indians since known north of the Isthmus. They lived in towns; their dwellings were comfortable, they cultivated the earth, wove, and dressed their females in garments of cotton and other fibrous plants, and were almost ignorant of the arts of war. ‘The mother of one of their chiefs complained of the brutal treatment of an Indian girl, by a soldier. Narvaez caused her to be thrown to his dogs, which tore her to pieces. Her son, the chief, remonstrated, and Narvaez cut off his ears. The Indians collected in a body and swept this Spanish brute and his army out of existence. They slew two-thirds of them, burned their ships, and the remaining two hundred embarking in a frail vessel, which they constructed, were wrecked and drowned. Only five were known to have es- caped. Cabega de Vaca, a priest, the chronicler of the expedi- tion and three companions, and Ortiz, a soldier. De Vaca and three companions, after probably eating a fourth, made a des- perate fight for life, and actually crossed the continent to the Yacqui river in the Mexican state of Sonora, on the Gulf of California, whence they returned to Spain, ten years after the expedition of Narvaez had sailed for Florida. De Soto was the first who made search in Florida for mines of the precious metals. He had returned with riches from New Spain; the only man in Pizarro’s army that brought any reputa- tion, save that of robber, from the conquest of Peru. He was fit- ting out his five ships when De Vaca returned to Spain in 1537. As the latter hoped himself to lead a similar expedition, he gave De Soto no,information about the mines, and there was little in his ‘‘ Relagam,” afterwards published, except rumors relating to the precious metals. At this time the region south and west of the Alleghanies was inhabited by the great Natchez family of Indians. They had reached a civilization higher than the Five Nations. The dwell- ings of the common people were commodious, of several rooms 62 ‘TRANSACTIONS OF THE [DEC. 6, each, their cellars filled with the products of their cultivation and other industries, those of the chiefs were larger and hung with prepared skins in the manner of tapestry. They worshipped a Great Spirit in their temples, believed in future rewards and punishments, and lived under the severe, though patriarchal government of their chiefs. It is a mistake to say, as historians do, that the advance of the Natchez in the arts of civilization was arrested by De Soto. Their relapse into barbarism dates from the first expedition of Ayllon, and received a fresh impulse from that of Narvaez. It was not strange that Ucita, whose ears had been cut off by Narvaez, should have sent back the messen- ger of De Soto, with the reply, ‘‘ Bring me no more promises from these people; I want their heads !” There was in De Soto’s army one who became the chronicler of the expedition. His name has never been certainly known. He calls himself a “ Knight of Elvas,” and his account of the expedition was first published in Portuguese in 1557. It bears intrinsic evidence of its author’s fidelity to truth, and many of its statements have since been confirmed. It is upon his ac- count that the fact that the Natchez Indians mined, smelted, and wrought in gold and copper must chiefly rest. The route of De Soto as described by the Knight of Elvas has been projected upon a chart by Mr. J. Carson Brevoort in a translation of the ‘‘ Relagam verdadiera” published by the Brad- ford Club in this city in 1866. Following that chart and my own translations of the Relagam, compared with the French translation of 1685, that by Hakluyt, printed in 1609 and 1686, and that by Buckingham Smith for the Bradford Club, it appears that the expedition marched inland from the head of Apallache or Oclockonnee Bay, pursued an irregular route a little east of north, crossing the Altamaha, to the Savannah river, not far from the site of the present city of Augusta. Be- fore leaving the coast, De Soto had fortunately secured one Ortiz, asurvivor of the party of Narvaez, who had been a captive among the Natchez for ten years, and had acquired their lan- guage. In him he had a competent interpreter in his inter- course with the Indians. While still within a few leagues of the coast, there was brought. . 1886. ] NEW YORK ACADEMY OF SCIENCES. 63 to De Soto ‘‘a young Indian who had been captured at Nape- taca. He said that he was not of that country, but from an- other, very distant, toward the sunrise, and was captured just as he had arrived, a traveller at Napetaca,—that his country was called Yupaha, was governed by a woman, whose city was of surprising grandeur ; that she drew tribute from all her neigh- bors; from some in commodities, from others in gold. Where- upon he described the manner in which the gold was taken out; how they smelted and refined it (le faisoit fondre, et affiner) as if he had seen it done a hundred times, or the devil had instructed him. So that those who were experts in the ways of working mines were certain that he could not have spoken so accurately had he not seen it; and the relation passed for a constant verity from the circumstances which confirmed it.” Proceeding on their journey, they passed Cutifachaqui on the Savannah, which they ascended, passing Chelaque to Xavala, where they reached the mountains, which deflected their course to the southwest, passing through the Indian provinces of Chiaha and Coga, to Tuscaluga in central Alabama. At many places they were told that across the mountains, to the north- ward, lay Chisca, rich in mines of gold. Thus at Chiaha, near the northeastern corner of Alabama, ‘‘ the Chief Acoste came to offer his services. And when De Soto asked him if he knew any rich and fertile country, he said that farther north he would find the province of Chisca where they smelted (fondoit) copper, and another metal more lively and more perfect, that this metal seemed much more precious than copper, but because of its soft- ness it was not used. This account conformed to what De Soto was told at Cutifachaqui, where we saw some small axes of copper which they said was mixed with gold.” De Soto made several attempts to reach these mines. Once a party set out to visit a chief, who the Indians said ‘‘ was a neighbor of the chief of Chisca, where the metal was found which the Governor believed to be gold;” but failed to reach their destination. From Coga, De Soto ‘‘sent thirty cavaliers and fifty footmen towards the province of Caluga, to find a road thence to Chisca, where the Indians had said he would find mines of copper and of that metal which resembled gold. These sol- 64 TRANSACTIONS OF THE [DEC. 6, diers marched seven days through a desert country, but returned dreadfully wearied, for they found nothing to eat but green cherries and corn stalks, in a miserable town of seven or eight houses.” The province of Chisca, as indicated by these extracts and as located by Mr. Brevoort, was nearly coincident with the gold fields of northern Georgia, but north of the most southerly range of the mountains. I have given the evidence so that every one can judge for himself whether these Indians practiced the smelt- ing of metals. The relation of the Knight of Elvas, through- out, gives an impression of the advanced state of civilization among the Indians, so that here, if anywhere, the knowledge of the smelting of metals should have existed. One fact throws a little doubt upon the correctness of De Soto’s route, as projected by Mr. Brevoort. His projection car- ries the route almost directly through the city of Dahlonega and the northern counties of Georgia. Members of the Academy, better acquainted than myself with the locality, will be able to say whether these counties are not within the gold fields. If they are, it is highly improbable that the sharp eyes of such a party of Spaniards would have failed to detect the, gold if they passed through them. The omission of all mention of silver in this ‘‘ Relation ” tends to confirm the suggestion that the materials of ornaments containing that metal, might have been obtained from the sunken ships, especially if they came from locaiities near the coast. There is no reason why the Natchez Indians should not have understood the smelting of metals of well as those of Mexico and Peru. The heroism and fine qualities of De Soto may command our admiration, without diminishing our satisfaction over the follow- ing record of good old Father Las Casas, the noblest Spaniard of the whole Castile de oro. ‘‘ The merciless tyrants have in- vaded these provinces since the year 1510. They all committed the same outrages, to put themselves by robbery and pillage into places of honor and profit, far above their quality. But God was pleased to punish them after a most signal manner, for they 1886. | NEW YORK ACADEMY OF SCIENCES. 65 all came to a most miserable end. ‘These brutes would have committed yet more villanies, had He not shortened their days. Most of these cruel villains perished miserably without the least contrition or repentance. Although God is infinitely gracious and merciful, there is reason enough to fear that they were con- demned to eternal torments.” December 13, 1886. STATED MEETING. The President, Dr. J. S. NEWBERRY, in the chair. Over one hundred persons present. The PRESIDENT exhibited, in illustration of his paper on Earthquakes, read October 18th, a series of lantern views, from photographs recently taken at Charleston, Somerville, and other localities in South Carolina affected by the late earthquake. December 20, 1886. STATED MEETING. The President, Dr. J. S. Newserry, in the chair. One hundred and thirty-two persons present. The PRESIDENT announced the death of Dr. Isaac Lea, a Corresponding Member, and described his life and work. Mr. Ermer L. CortHett delivered an address upon THE ISTHMIAN SHIP RAILWAY. (Illustrated with Map, and Lantern views. ) Adjournment until January 10th, 1887. January 10, 1887. REGULAR BusINEss MEETING. The President, Dr. J. S. NEWBERRY, in the chair. Twenty-three persons present. 66 TRANSACTIONS OF THE [san. 10, The Report of the Council was received, which made the fol- lowing recommendations : 1. That the pending amendment to the By-Laws, increasing the fees and dues to ten dollars be adopted; and that all the Publications of the Academy be distributed free to all the Resi- dent Members and Fellows. Il. That the Academy authorize the Council and the Publi- cation Committee to change the Annals from a regular or yearly publication with a fixed subscription price, to an irregular or occasional publication, at special prices to persons not members; and to keep the ‘* Zransactions” the regular periodical, with a subscription price. Pending the adoption of these recommendations, the Secre- tary made a verbal report in behalf of the committee which was appointed at the meeting of December 6th, 1886, to send a circu- lar to all the Resident Members asking for their individual opinions upon the question of increasing the fees and dues to ten dollars, which report was to this effect: Sixty replies had been received, of which number forty-five were decidedly in favor of the increase, and six expressed a willingness to make the increase. Nine replies were negative, or gave adverse opinions. The Secretary also stated that these replies had been laid before the Council in the making of the recommendations. After some discussion, the recommendations were adopted unanimously. Dr. N. L. Britton read the following NOTE ON THE GROWTH OF A VINEGAR PLANT IN FERMENTED GRAPE JUICE. My attention was recently directed to certain remarkable growths effected by the Vinegar Plant under circumstances evi- dently peculiarly adapted to its development. In September, 1884, about a gallon of grape juice was obtained and allowed to undergo a certain amount of fermentation. It was bottled dur- ing the ensuing winter and the bottles placed on the upper shelf of a closet, where I found them on July 25th, 1886; they had been then standing undisturbed for about eighteen months. 1887. ] NEW YORK ACADEMY OF SCIENCES, 67 The closet was dark, but was generally opened onceaday. The temperature to which the bottles and their contents had been exposed varied from the freezing point to the highest indoor summer heat, probably about 85° F. Their contents had never been frozen, so far as known. On the above-mentioned date the liquid in several of the bottles was an extremely acid vine- gar, and in these were the peculiar growths about to be de- scribed. I will give an account of the bottles successively. Bottle No. 1.—This was an ordinary green glass wine-bottle of about a quart capacity, with a neck a little over an inch in external diameter, a base three inches in diameter, and having a nearly flat bottom. The cork was loose, admitting access of air. The surface of the liquid rose to within an inch of the cork. When first observed, a solid cylinder of tough, white, gelatinous material was standing upright in the bottle. Its diameter was 22 mm., its length 215mm. Another similar cylinder stood alongside of this one, having the same diameter and a length of 50 mm. This had evidently become detached and fallen from the longer one at some time, and subsequently the growth of the latter had been continued. During the time which has elapsed since July 25th, the larger cylinder has twice been broken off in the bottle in the course of moving it from place to place, and an additional length of gela- tinous cylinder to the length of 85mm. has been formed by growth downwards from the surface of the liquid. ‘The total length of gelatinous cylinder made in this bottle during the two and one quarter years has thus been 400 mm., about 16 inches and its volume about 12 cubic inches. The cylinders are distinctly stratified by an alternation of translucent with opaque layers. On the first day of examination the liquid was quite clear in all parts of the bottle except the very bottom, where, by gently shaking, considerable turbidity was noticed. As this bottle made a fine museum specimen and it would have been necessary to break the glass in order to extract the cylinders, it was left intact and further examinations conducted on the others. Bottle No. 2.—A green glass pint bottle, sloping from the mouth downwards, with no distinct neck and a conical bottom. In this a gelatinous cylinder exactly resembling that in No. 1, 68 TRANSACTIONS OF THE [san. 10, had formed from the surface of the liquid to the bottom. Its diameter was 15 mm., length 240 mm. or about 9.6 inches; this was in a single piece, but was broken in getting it out. Its ex- treme lower portion was of somewhat looser consistence than the parts above. ‘T’o the naked eye this was seen to be distinctly stratified throughout by an alternation of opaque and trans- lucent layers varying from the thickness of writing-paper up to one or two millimeters. The superincumbent vinegar was perfectly clear when first seen, and contained only a very few cells of some species of Sac- charomycetes similar to those next described. The turbid liquid contained numerous Saccharomycetes cells, some spherical and detached, others in pairs or groups of threes when they were oblong, about twice as long as broad and at- tached end to end. Some of these were budding; their granular contents were well defined undera 0.1 inch water immersion objective. There were also myriads of smaller, spherical cells, mainly in rows or chains of from three to eight, many of the latter number being observed. Some of these chains were enwrapped in a transparent substance, apparently gela- tinous; others were observed to be loosely connected, form- ing colonies; many transparent masses of gelatinous material contained numerous chains of these smaller spherical cells, which appear from figures and description in Grove’s ‘‘ Bacteria and Yeast Fungi” to be the Saccharomycetes mycoderma, Reess, (Mycoderma cerevisie, Desmazieres). Associated were swarms of extremely minute microbes, their length about one half the diameter of the smaller spherical cells, their diameter probably about one-eighth their length, and in rapid vibratory mo- tion. No other organisms were detected. The gelatinous cyl- inder was tough in texture, requiring considerable force to pull fragments from it, and could be lifted between the fingers with only a slight compression of its periphery. Fragments taken from near its top and from points one-half and three-fourths the way down showed a nearly amorphous structure, which I could at times imagine was irregularly cellular, but, if so, there is no definite shape to the cells. A fragment from the extreme base of the cylinder was, however, seen to be almost entirely 1887. ] NEW YORK ACADEMY OF SCIENCES. 69 composed of chains and detached individuals of the chains above noted, immersed in the jelly-like substance of the cylin- der. It seemed as though this was built up by the multiplica- tion of the S. mycoderma and the deliquescence of its cell walls. The liquid contents of this bottle with the gelatinous cylin- ders were placed in a loosely corked preserve jar of three inches exterior diameter, the bottle being broken in extracting the cylinders. On August 1st, one week after my first examination, this liquid was covered with a film of the gelatinous material 2 mm. in thickness. On August 14th this film had increased to 6 mm. On October 3d it had reached a thickness of 12 mm. and was completely covered with a vigorous growth of the mould, Peni- cillium glaucum, in spore condition. There were two spots of another mould of an orange color,;and bearing globular sporo- gonia. On November Ist the Penicillium hyphe had almost entirely disappeared, and an enormous number of black spores were all that was left to represent it. Some of these spores still remain on the jelly, which seems to be gradually decomposing. Bottle No. 3.—The liquid had been mainly poured off from this bottle and its contents disturbed before my attention was called to these phenomena; only a small turbid portion re- mained in the bottom. The character of this was precisely the same as that of the turbid liquid in No. 2, containing some of the larger Saccharomycetes cells, multitudes of chains of S. myco- derma cells, and myriads of vibrating microbes. The gelatinous matter in this bottle had apparently been less abundant than in the others and had dried and contracted considerably, so I could not tell what its original shape had been. The bottle was similar in shape to No. 1. When I examined the mass it was resting on one side of the conical base and was itself coni- cal, 60 mm. high with a base diameter of 40 mm. It clung closely to the surface of the glass and was only detached with considerable force. Its surface was completely covered with a white, downy coating about 1 mm. in thickness, which, under the microscope, was seen to consist of transparent, irregularly 70 TRANSACTIONS OF THE [JANn. 17, branching threads, a true mycelium. The diameter of these hyphe was about that of the larger Saccharomycetes cells. Borne laterally on these threads at long and irregular intervals were exactly spherical cells of about the thread’s diameter, which had granular contents. This mycelium was only on the parts of the gelatinous mass exposed to the air. The bottle had been emptied of liquid six days before my notes were taken. I was unable to identify this mould from any descriptions or figures at my command. Bottle No. 4.—This was similar in shape to No. 2, but was more tightly corked. A verysmall amount of gelatinous mate- rial had formed in its neck. The upper portion of this was cov- ered with the same kind of mould found on the mass in Bottle No. 3, and the turbid fluid at its bottom contained cells of S. mycoderma. There were several more bottles of fermented grape juice in the same closet. but they were tightly corked and contained no gelatinous matter. Mr. A. L. Ewrne exhibited a photograph of the shark (Lamna cornubica) recently shown at Fulton Market. THE PRESIDENT exhibited an etched section of an iron me- teorite from Toluca, Mexico. He spoke of the chemical and physical character of meteorites, saying that they had appar- ently crystallized by slow cooling under great pressure, and that it-seemed probable they were fragments of disrupted bodies of great size, analogous to the asteroids or minor planets. January 17, 1887. STATED MEETING. The President, Dr. J. S. NEWBERRY, in the chair. Thirty-nine persons present. Mr. A. L. Ewine exhibited a specimen of limonite ‘‘ pipe- ore” from Centre Co., Pa., having one of the pipes lying at an angle of 45° with the others. * 1887. | NEW YORK ACADEMY OF SCIENCES. 71 Mr. B. B, CHAMBERLIN showed a specimen of pyrite changed into limonite, from Mott Haven, New York Oity. Mr. Wixi1am KE. HippEN read a paper ON AN IRON METEORITE THAT FELL AT MAZAPIL, MEXICO, DURING THE DISPLAY OF *‘ BIELID”’ METEORS, NOVEMBER 27TH, 1885, WITH AN ACCOUNT OF ITS FALL, BY PROF. JOSE A. Y BONILLA, DIRECTOR OF THE ZACATECAS OBSERVATORY. (Published in the ANNALS, Vol. IV.) The meteorite was exhibited. The subject of the paper, and meteors in general, were discussed at length by Pror. J. K. Rees, Pror. W. P. Trowzrines, the PRESIDENT, and the author of the paper. PrEsIpDENT NEW- BERRY also exhibited some stone meteorites. Mr. GeorGe F. Kunz stated that he had recently acquired an eighty-pound mass of ‘METEORIC IRON FROM CARROLL CO., KENTUCKY, which was largely transparent olivine, and apparently identical with the small masses found by Prof. Putnam in the Little Miami mounds. Altogether four specimens of this character were known, which might possibly be fragments of the same meteor. In the spring of 1883, Professor F. W. Putnam found on the altar of mound No. 3 of the Turner group of mounds in the Little Miami Valley, Ohio, several ear ornaments made of iron (see Fig. 1),’ and several others overlaid with iron. With these were also found a number of separate pieces that were thought to be iron. They were covered with cinders, charcoal, pearls (two bushels were found in this group of mounds), and other material, cemented by an oxide of iron, showing that the pieces had been subjected to a high temperature. On remoy- ing thescale, Dr. Kennicutt found they were made of iron of meteoric origin.” One of the pieces weighed 28 and another 52 grams. ‘Tam indebted to Professor Putnam for the cuts from which figs. 1 and 4 are printed, as also for information kindly furnished me. 216-17 Report of Peabody Museum of Archeology, p. 382. 72 TRANSACTIONS OF THE [JAN. 17, In the autumn of 1883, another mass was found on the altar of mound No. 4 of this same group, which weighed 767.5 grams (27 oz.). Dr. Kennicutt suggests that these were all parts of some larger meteoric mass. The results of the investigation were published in connection with the description of the Ata- cama meteorites, because iu structure they approached more closely to the latter than to those of any other occurrence. In the Liberty group of mounds in the same valley, Professor Put- nam found a celt five inches long, and in another of the Turner mounds, an ornament five inches long and three inches wide, made also of this same meteoric iron. It was not until after the above masses had been found that. Fic. 1.—Earring made of Meteoric Iron. the Carroll County meteorite was brought to my notice; after a careful comparison, I have reached the conclusion that the irons from the Ohio mounds and the Carroll County meteorite probably belong to one and the same meteoric fall. Hither the former was broken from the main mass by the mound-builders themselves, or they were all fragments of the same fall, scat- tered as were the Estherville meteorites, or, as suggested by Dr. J. Lawrence Smith, were those of Coahuila, and also, by Huntington,’ the Sevier, Cocke County, and Jenny’s Creek irons. at) haslitvn) othald Walp eee Bes ees be ae 1 Am. Jour. Sci., III., xxxiii., p. 115. 1887. ] NEW YORK ACADEMY OF SCIENCES. 73 The Carroll County meteorite was found in 1880, about three- fourths of a mile from Eagle Station, Carroll County, Ken- tucky. The distance to the Turner mounds, where Professor Putnam found the meteoric iron and the ornaments made of it, is about 60 miles. The mass, which weighs about 80 pounds, Fic. 2.—Carroll County Meteorite, upper side. + natural size. or 36.5 kilos (figs. 2and 3), is almost square, measuring 19° (7% inches) in thickness, 22°" (10 inches) in width and 29™™ (12 inches) in length. The surface is rusted in some places to a depth of 10 to 12™™, and deep pits, some 2°™ across, are observed in spots where grains of olivine have prob- 74 TRANSACTIONS OF THE [JAN. 17, ably dropped out. All of the original crust has disappeared. The mass is largely made up of fine yellow, transparent olivine, resembling closely that of the famous Pallas iron. This meteor- Fia. 3.—Sections of the Carroll County Meteorite. Natural size. ite belongs to the siderolites or ‘‘syssidéres” of Daubrée, and the Pallasite group. Figure 3 shows three sections of the Carroll County mass, the light portions representing the iron and the dark portions the Fia. 4.—Section of the iron from the Turner Mounds olivine. Figure 4 shows a similar section made by Dr. L. Ken- nicutt, of the Turner Mound mass. The specific gravities of the three sections figured are given below, with those of the Ata- cama and Turner’s Mound meteorites. 1887. ] NEW YORK ACADEMY OF SCIENCES. 75 No. Carroll County. Turner’s Mound, Atacama, pe ea een 4,72 4,35 Act ¢ & AT 5 ee ee Ww ms i ‘Wa, ‘ FN 144 natural size. Fie. 5.—Catorze Meteorite. N NS mM M Taking the specific gravity of the iron at 7.6, and that of the olivine at 3.3, we find that all of these meteorites consist of 76 TRANSACTIONS OF THE [JAN. 17, about three parts of olivine to one part of iron. The iron in the Carroll County meteorite is scarcely more than sufficient to hold the mass together securely, as the olivine is in so much larger crystals than in the Atacama meteorite. On etching, small fine Widmanstitten markings are produced. By reflected light minute crystals of bronzite can easily be recognized, and analysis. showed the presence of chromite in fine grains and a very small quantity of schreibersite. Mr. Kunz also described A- NEW METEOR FROM CATORZE, MEXICO. This mass, weighing 92 pounds, was found by a miner near Catorze, San Luis Potosi, Mexico, in 1885. It is 31.5°™ (123 Fic. 6.—Catorze Meteorite, Widmanstitten Figures. Natural size. inches) long, 34.5°™ (133 inches) wide, and 20 (8 inches) thick. It shows beautiful raised octahedral markings. On one side an opening 9™ (34 inches) long has been made, and a piece of a chisel of native copper left wedged in it. This piece, which is partially covered with oxide of copper, is 22™™ (4 inch) long on one side, 33™™ (14 inch) on the other, and 14"™ wide. This iron is one of the Caillite group of Stanilas Meunier and shows the Widmanstiitten lines very finely (see fig. 6). It resembles the irons of Augusta County, Virginia, of Glorieta Mountain, and others of this group. No troilite was observed, the mass having been cut very little, and schreibersite is only sparingly present. The specific gravity of the piece is 7.509. An analysis has 1887. ] NEW YORK ACADEMY OF SCIENCES. 77 been made by Prof. James B. Mackintosh, of Lehigh Univer- sity. January 24, 1887. STaTED MEETING. The President, Dr. J. 8. NEWBERRY, in the chair. A very large audience present in the East Lecture Room of the Library Building, Columbia College. The first lecture of the Popular Lecture Course was given by Pror. WILLIAM Lipsey, of Princeton College, on RECENT EXPLORATIONS IN ALASKA. (Illustrated with lantern views.) January 31, 1887. STaTED MEETING. The First Vice-President, Pror. O. P. HUBBARD, in the chair. Thirty-four persons present. Mr. B. B. CHAMBERLIN exhibited two specimens of tour- maline from Washington Heights, one of them being black, in oligoclase, the other a spreading or radiating crystal. The following paper was read by title: A REVIEW OF THE CHATODONTIDZ OF NORTH AMERICA, by Cart H. EIGENMANN and JENNIE E. HORNUNG. (Published in the ANNALS, Vol. IV.) Pror. W. P. TRowBRIDGE read a paper ON SUB-SURFACE WATER-SUPPLY FOR CITIES AND TOWNS. Two or three years ago, I prepared a paper for the Sanitary Engineer, describing the driven wells, and the method of con- necting them with pumps, by which a large supply of pure water had been obtained for the city of Brooklyn from the gravel deposits on Long Island. ‘The simplicity of the means 78 TRANSACTIONS OF THE [JAN. 31, adopted and the large and constant volume of water obtained were alluded to as constituting a new and successful experiment on a large scale in connection with the supply of water to towns. Since the publication of the paper referred to, the Messrs.. Andrews & Co., contractors, have established two additional “‘plants” along the line of the Brooklyn Aqueduct, increasing the supply for the city to eighteen millions of gallons daily from this source alone—a quantity equal to one-sixth of the supply to the city of New York at the present time. This large volume of water is obtained from four hundred and sixty (460) 2-inch tubes (equivalent in area of cross section to a single tube or pipe 44 inches diameter) driven from forty to seventy feet into the gravel deposits. On a trial-test, these tubes have furnished twenty-seven millions of gallons in twenty- four hours. Eighteen millions is not, therefore, the maximum supplying capacity of these wells at this time. It is not contended that there is anything novel in the idea of obtaining water for any purpose from the unconsolidated or loose detritus of the earth’s surface; but the means and ap- pliances by which such large quantities are drawn continuously and permanently from a few tubes driven into the ground are so effective and simple, and so much has been done to encourage further operations of the same kind, and to throw light upon the characteristics of these underground water-bearing deposits, that it may be said that new resources, in connection with the water supply of the largest towns, have been opened to the engineer—resources not always available, it is true, but in many cases highly practicable and economical. The engineer who seeks a source from which may be obtained a proper supply of water for a town, must take into considera- tion a great variety of circumstances. Among these, the me- teorological and geological conditions which prevail in the dis- trict are most important, since these influence the quantity as well as the quality of the water obtained. Of all the meteoro- logical agencies, there are none which have more controlling influence on the physical geography of the globe and the adaptation of any part of its surface to the necessities of the 1887. | NEW YORK ACADEMY OF SCIENCES. 79 human race, than those which relate to rainfall and the reflux of the condensed waters of the sea. The causes which determine the quantity of rain which falls in any region are various: ocean currents, aerial currents, monntain ranges, extended valleys and plains—all produce their effects; and, although the most varied extremes occur of regions where vegetation is luxuriant on the one hand, and where deserts exist without rainfall on the other, yet such is the constancy of nature in her great cycle of changes, that each place receives its appointed share almost un- changed from year to year. The average rainfall of a region is, therefore, in most civilized countries, one of the best established of all meteorological phe- nomena. It is not so, however, in regard to the return of the waters to the sea. The flow of surface streams may, it is true, be deter- mined with approximate accuracy, and their courses are well de- fined ; but the disposal by nature of that large part of the rain which does not appear in the rivers and brooks, as they accumu- late in magnitude toward the sea, is involved in much obscurity. A portion of the condensed vapors is known to be absorbed by plants, and a portion is reévaporated, but a still greater part, apparently, disappears beneath the earth’s surface. By what precise channels this large volume of water ultimately reaches the ocean, how much of it enters the covered out-crops of porous strata and, finding its way deep into the earth’s crust between underlying and overlying consolidated beds, is ulti- mately discharged underneath the waters of the ocean; how much enters faults and fissures, and again issues in springs of pure or mineral waters; how much is concerned in excavating underground courses through or among the softer or more soluble rocks, or follows channels already thus excavated, is not and cannot be known. But that no inconsiderable portion of this subterranean flow follows more shallow channels in the loose detritus upon the surface seems probable. In most coun- tries where the rainfall is copious, moderate excavations at the surface reveal the presence of water. In our own country every farm has its well, whether it be situated on a hill or in a valley ; and, while these wells occasionally become dry in very dry years, 80 TRANSACTIONS OF THE [JAN. 31, it is apparently, in most cases, because they have not been sunk deep enough to reach those water-bearing beds of gravel and sand from which a perpetual and continuous supply might be obtained. The farmer, in sinking a well, looks gratefully for the first indication of water, and as his needs are not excessive, the sinking of the well is stopped when the upper surface of the first ter-bearing stratum is reached. The methods and appli- ances at his command do not permit him to sink deep into watery ground. The ‘‘ driven well” goes deeper, and the tube is easily driven through soft ground to any desired depth; while the artesian boring proper pierces the solid strata still lower, if necessary, and draws its waters from sources more distant than those which supply the common or the driven well. The proportion of the rainfall which passes off by the surface streams is so variable in different places that actual gauging of the streams is generally necessary to determine it. Over a large portion of our Northern States, this proportion is from 30 per cent to 90 per cent of the rainfall, depending upon the seasons, the surface topography, and the geological characteristics of a district. From 10 per cent to 70 per cent of the rainfall for the same localities disappears, being absorbed by plants, or re- evaporated from the surface, or sinking beneath it, and of this latter portion there is no doubt that, in many parts of our coun- try, nearly all follow shallow sub-surface channels slowly to the sea-levels. Artesian wells have become so common in every quarter of the globe as no longer to excite especial interest, beyond that which may be attached to the great depths of some and the large volume of flow from others. Asa general rule, the hard or consolidated strata of the earth’s crust have to be pierced, often at very great depths, to reach water-bearing strata which have been pointed out by precise geological knowledge, or which are sought for with much expense and uncertainty where such knowledge is wanting. While the mechanical processes of boring these wells have reached such a degree of excellence and certainty that indi- viduals or companies may now be found ready to undertake for 1887. ] NEW YORK ACADEMY OF SCIENCES. 81 a specified sum per foot the sinking of an artesian well to any reasonable depth, yet the great cost and the uncertainty of success of any one boring, as regards the volume of water which may be permanently obtained, have caused this method of search for water to be adopted for cities and towns only as a last resort. If it be proper to classify the systems which have been re- ferred to as the ‘‘artesian” and the ‘‘driven well” systems, it can be said of the latter that the methods of exploration and well-sinking which have been recently developed seem to offer incontestable advantages, and to promise results of the greatest value and importance. Facts have been established, in the ex- plorations already made in different places, which seem to offer _ strong inducements for further and systematic researches, not ‘only from an economic, but from a scientific point of view. Among the scientific questions presented, those which appear to be of special interest relate to the causes of some of the peculiar phenomena of deposition and arrangement presented in the in- terstratified beds of gravel, clay, and sand which are found to exist; and, if these are connected in any way with ancient river beds, the possibility of tracing out these beds with greater cer- tainty. A study of these surface deposits by the methods which have been introduced for the driven wells, and which are attended with little difficulty and expense, comparatively, seems to offer, at least, an attractive field for economic and scientific explora- tions. Through the kindness of Mr. W. D. Andrews I have ob- tained sketches which illustrate the construction of one of the four “plants” on Long Island from which the supply above- mentioned is obtained, and also a sketch illustrating the pro- cess of boring or prospecting adopted; and another repre- senting a section of the deposits of sand, gravel, and clay in the vicinity of one of these plants to the depth of 433 feet. In these sketches, Fig. 5 represents a plan of the whole ‘*plant.” The system of driven tubes occupies a space about 800 feet long and 15 feet broad, parallel with the line of the Brooklyn aqueduct. The tubes are in two rows about 15 feet 82 TRANSACTIONS OF THE [JAN. 31, apart, while in each line the tubes are about 12 feet apart. Fig. 5 shows the relative position of the Brooklyn aqueduct M, the pump house O, and the driven wells in two rows DD, Fig. 4. Fig. 4 is an enlarged view of a portion of the plan. In this sketch it will be seen that each tube is connected with a large pipe A, lying midway between the two rows of driven tubes and connecting them with a central or common chamber H, from which tie suction pipe J extends to the pump house. In this figure the connecting pipes C C and the junction B B are shown more clearly than in Fig. 5. The pumps in the pump house O draw water from all the wells simultaneously and discharge it directly into the aqueduct through the pipe N. (Fig. 5.) Fig. 1 represents a vertical section drawn through two driven wells, showing the extension of the tubes downward through several strata of sand and gravel to the lower stratum G, from which the supply is drawn. ‘The ends of the tubes are pointed to facilitate their being pushed downwards, and are perforated for several feet in length near the ends, to permit the entrance of the water; the perforations being covered with a wire netting to prevent the introduction of large pieces of gravel. Fig. 2 illustrates the apparatus fcr prospecting for water. A two-inch tube is driven down for a few feet at the surface, with fittings at the top which close the top, except thata spout shown in the figure is attached to discharge water, sand, gravel, and clay intoatub. ‘These fittings permit of a smaller tube being inserted into the top of the larger, with a hollow handle con- nected with a flexible hose to a portable pump. A man, by grasping this hollow handle, can churn the inner tube up and down while water is being forced into it from the pump. The bottom of this inner tube is chisel-shaped, but there are two openings near the bottom, which permit the water pumped through the inner tube to enter the space between the inner and outer tubes near the bottom. The churning action cuts up the sand and gravel, and as it is mingled with the water forced in, both the water and sand or clay are forced to the surface up- wards between the two tubes and discharged into the tub. A barrel or portable tank supplies the water if necessary. ANSACTIONS OF THE NEW YORK ACADEMY OF SCIENCES. Sand*Gravel + Gravel EE —_—= 360}-—______ Sand w@ravel lise Ce ee Grey brown Clay 314) Rect Clay =5> er 40: fand vy Gravel ee aaa ge ORO Sketch showing apparatus for prospecting for Section of deposits on Long water, Island in the vicinity of the driven wells, 4 ; a) aye as nies | / 1887. | NEW YORK ACADEMY OF SCIENCES. 83 The specimens discharged into the tub are collected and pre- served, and thus a complete section of the strata may be obtained. The tubes may be extended by adding sections at the top as the boring extends downwards. Fig. 3 shows the section obtained near one of the plants on Long Island to the depth of 433 feet. Two of the gravel deposits passed through were composed of coarse rounded gravel, almost wholly free from any admixture of fine sand or clay, an evidence that there is a continued flow of water among the particles of gravel. Mr, Henry KE. Knox, Jr., formerly a student in the School of Mines, has been for many years engaged under the direction of the Messrs. Andrews in prospecting for water in various places, and I am indebted to him for the description of the prospecting device just described. Mr. Knox found, between Albany and Troy, an extensive bed of gravel beneath a bed of fine clay, from 16 to 25 feet thick near the surface. The gravel bed is from 17 to 35 feet thick, about 700 feet wide and of indefinite length, it having been traced about half a mile longitudinally. The gravel from this bed is entirely different from that on Long Island. It is composed of coarser grains or fragments of dark-colored rock, nearly all of uniform size, and less rounded than those from Long Island, showing evidence of that kind of attrition which comes from running water rather than wave action. Mr. Knox found precisely the same gravel in his explorations near Utica; and under a bed of clay, 118 feet thick, near Al- bany, he found a bed of clean gravel, of nearly uniform size and uniform material, but composed of angular, water-worn pebbles as large as pigeons’ eggs. One of the most important questions connected with the system adopted on Long Island, and which has been repeated elsewhere on a smaller scale, was the permanency of the full supplying capacity of the wells. It was urged by some distinguished engineers that the tubes must tap sheets or reservoirs of still water, and that a continued draught upon the system must speedily exhaust the reservoirs. Experience has not confirmed this view. Mr. Knox informs 84 TRANSACTIONS OF THE [JAN. 31, me that, of the fifteen hundred or two thousand wells selected and driven by himself, not more than two or three have ceased to act, and that in nearly all the supply remains undiminished. Experiments were made on Long Island to determine the line of depression of the water-level in the ground immediately adja- cent to the plant of one hundred wells, while the pumps were drawing to their full capacity. Test wells were sunk just outside of the plant on four sides, and a line of test wells extended out to a distance of 4,000 feet from the pump-house. Observations were made during three months. At the distance of 4,300 feet, the water-level was re- duced about 6 inches. At a distance of 2,300 feet, about 2 feet 2 inches, and in the immediate proximity of the wells, within a distance of 300 feet, the depression was 4 feet 8 inches. When the pumps were stopped, all the levels were restored. The rate of flow to wells sunk in sand or gravel depends, of course, upon the compactness of the material of the water-bear- ing stratum, the resistance to the flow being proportional to the narrowness of the minute channels through which the water must flow, and to the number of windings and turnings which a particle is forced to take throughout its course to the pumps. The velocity of a particle of water running into an ordinary fil- tering gallery along the margin of a stream is generally less than one foot an hour. The velocity of a particle flowing towards the pumps in the driven-well plant on Long Island, taken a little outside the rectangle formed by the hundred wells, is about the same—a velocity too small to be directly perceptible to the eye. This small velocity shows what great relative resistances are encountered. The form of the water-surface will, therefore, depend almost entirely upon the coarseness or compactness of the materials through which the water passes, and is not to be taken as a measure of the degree of exhaustion of the source of supply. In all the explorations thus far made, it has been found that the gravel-beds, available for water, are not continuous over indefinite areas, nor of uniform thickness, but certain beds and particular channels in certain beds appear to constitute the 1887. | NEW YORK ACADEMY OF SCIENCES. 85 underground water-ways, rendering systematic explorations necessary. The questions which naturally arise, concerning these de- posits, are: What have been the causes of the peculiar arrange- ments of sand, graveland clay? Are the gravel deposits the beds of ancient water courses, along which the finer sands and clays have been washed away by thestream? Can these old river beds, if they exist, be traced and identified throughout their courses? In the exploration between Albany and Troy, the appearance of the gravel found seems to indicate a common origin with that of Utica, and it is the opinion of Mr. Knox that the same beds extend along the valley of the Mohawk between these points, but by a route not identical with the present course of that river. The mode of exploration which has been described renders it more simple and less expensive than might be imagined, to con- duct such researches, although not probably within the means of private explorers. An instance has recently come to my knowledge which adds new interest to this subject, inasmuch as in this case water was procured in abundance froma sub-surface deposit in loose ma- terial in a region where the small rainfall and the absence of permanent surface streams has heretofore been considered a serious obstacle to any permanent settlement of the country. Mr. Arthur Macy, a graduate of the School of Mines, having been appointed to take charge of the famous ‘‘ Silver King” minein southwestern Arizona, found that for the extensive milling operations indispensable in the treatment of the ore, an amount of water would be necessary for which no adequate supply appeared available. A valley of several miles in extent. lay above the mines, and from the appearance of the country, he concluded that this valley, from which flowed a small torrent in the rainy season, must contain sub-surface water. He excavated two open wells, one 15 feet and the other 25 feet deep, at the outlet of the valley, and about 300 feet above his mills in vertical elevation and three miles distant from them. A 3-inch pipe was carried from the mills up the valley to the wells, where it was connected to two siphons, one from each well; through these siphons, without the use of pumps, he ob- 86 TRANSACTIONS OF THE [JAN. 31, tains a continuous supply throughout the year of 200,000 gallons per day. There is no doubt that Mr. Macy has thus discovered a prac- tical method of obtaining waterin Arizona, which may be re- peated in many parts of that territory, and which will be found applicable in many other regions heretofore supposed to be prac- tically deprived of water. There is now, at least, abundant experience to encourage the search for and use of subterranean water for the most important uses of life, in the shallow and loosely compacted deposits which cover plains and valleys. Another significant example is found in the new water-supply for the villages on the east shore of Staten Island. A large part of this island is known to be coy- ered with drift. That portion which isembraced between the principal ridge of serpentine rocks running through the middle of the island from north to south, and the dike of basaltic rock which skirts the western shore of the island, both of which have been described by Dr. Britton before the Academy,’ is especially to be noted as bearing water; a very large part of the rainfall, doubtless, because the whole area of eight or ten square miles is peculiarly devoid of surface streams. Along the southwestern shore of the island there are unmis- takable indications that the underground flow reaches the sur- face only a few feet above high-water mark. Here the Crystal Water Co. have sunk large tubes about 40 feet into the drift. From these tubes the water destined for the villages along the eastern shore of the island is pumped to a reservoir, 35 miles distant, situated on the top of the dividing ridge referred to, whence it descends through pipes by gravity about 24 miles fur- ther to the eastern shore, furnishing a head of about 250 feet. A few years ago Staten Island and Long Island were supposed to be almost destitute of water. when the prospective wants of their large and increasing population were considered. Now it may be said that in this respect, though isolated from the main land, they are better off in many respects than New York City. I recently examined, at the request of the Trustees of the village *! The Geology of Richmond Co., N. Y., Annals N. Y. Ac. Sci., Vol. II. 1887. | NEW YORK ACADEMY OF SCIENCES. 87 of Edgewater, the facilities presented on Staten Island, and had no hesitation in advising that a contract might be safely made with the Crystal Water Co. for all the water which would prob- ably be needed for along term of years. Such a contract has since been made, and the water supply for the towns referred to may be considered assured. Perhaps my own interest in this subject is derived partially from some of the earlier associations of my life. In the State of Michigan, where I passed my boyhood, there is a tract of country 20 or 30 miles broad, bordering on the river and lake St. Clair, the Detroit River, and Lake Erie, which is low and _ heavily wooded, and in wet seasons almost swampy. The settlers of this region had little difficulty in finding water a few feet below the surface, but there were few surface streams, and I have known the farmers to be obliged in very dry seasons to drive their stock several miles daily to water. A belt of country north of this, and stretching from Lake Huron in a southwest direction quite across the state to Lake Michigan, is covered with the most beautiful little lakes of pure and sparkling water, which never be- come stagnant and never dry up. Farther north again, toward the northern part of the State, are found extensive pine barrens, where again there are but few rivers and streams; but I have seen wells driven there from 6 to 10 feet only to an abundant supply of water. The little lakes I have referred to are replenished from the exposed outcroppings of gravel beds, and while they are often linked together so as to constitute the sources of considerable streams, the water from most of these lakes seems to sink away slowly again and to flow underground in broad sheets toward the great lakes. Nearly everywhere in this State, water in abundance can be found by driven wells; and I am told that in the regions where the early settlers suffered so much from swamps and mud in winter, and drought in summer, surface drains and tube-wells have created an entirely new condition of things favorable to the farmer. An objection has been frequently urged against the use of water from these shallow sub-surface deposits that there is danger from pollution or contamination of the water by sewage and surface drainage, the drainage from cemeteries, etc. 88 TRANSACTIONS OF THE [JAN. 31, While it would obviously be undesirable to establish a driven well plant within the limits of a populous city, it may be said that the necessity for so doing is never likely to occur. More- over, the purifying influence of the soil by infiltration is known to be very effective ; the well-known processes of sewage dispo- sal by irrigation and downward filtration are based upon this property of the ordinary porous soils. A microscopic analysis of the effluent water from the irriga- tion fields of Paris showed that the number of microbes in the sewage was reduced from 20,000 per cubic centimetre to 12 per cubic centimetre, and that the effluent water from the irrigation fields contained fewer microbes than the water supplied to Paris for domestic uses. (See Gray’s report to the City Council of Providence. ) The water being drawn from considerable depths, usually, the purifying effect of the slow downward filtration from the surface would probably be much more complete than is produced by any artificial filtration. It should be a source of public congratulation that, while our rivers and streams must become polluted by a growing population, nature furnishes another source of water-supply sO abundant. and widespread, so pure and so easily procurable. Explorations and investigations having in view the more thorough study of this underground water-supply deserve, and should receive at the hands of the public, the most earnest ap- preciation and encouragement. Pror, A. A. BRENEMAN spoke as follows : Every plan for supplying water for domestic use to cities must. be regarded from the standpoint of the chemist as well as from that of the engineer. Unfortunately for sanitary interests, it often happens that the chemist is called in only when some glar- ing defect in the operation of a system is met with which might have been prevented if his counsel had been sought at the be- ginning. Considerations of quantity and permanence of supply, so important in themselves, have too often been allowed to over- shadow the question of the quality of the water to be used. As a result of this policy, we have to face the fact that not one-tenth 1887. | NEW YORK ACADEMY OF SCIENCES. 89 of the large cities of this country are supplied with water that is really wholesome or good. There is some excuse for this state of things in the fact that resort to the water of rivers and streams is generally had under pressure of danger from polluted wells or from failure of previous sources; and when the new system is decided upon, there is rarely time enough for a thorough inquiry into the character of the water to be taken. It is characteristic of sanitary progress, however, that the ten- dency towards chemical investigation at the outset in such cases is a growing one. The driven well, especially in its later development as the gang-well system, seems to offer a cheap and speedy way of sup- plying water in any desired quantity to acommunity. It has obvious advantages over an aqueduct or pipe-line bringing water from a distance. But there is a chemical question yet to be con- sidered in regard to it. Unless the surface waters of the district in which wells are to be sunk are themselves unobjectionable, the method has little to recommend it to permanent application. The action of powerful pumps which draw from a limited area such enormous volumes of water as the system must supply will result eventually in drawing in all water, surface as well as sub- terranean, which the vicinity will yield. The increased depth of these wells as compared with surface wells is really very slight, when we consider the greatly increased draughts which are made uponthem. It has been shown that there are considerable varia- tions in the level of the subterranean waters, during the action of the pumps in a gang-well system, even at a distance from the pipes. Such changes of level must be proportionally greater near the wells. What is to prevent the gravitation of surface water to fill the vacuum thus created ? The compact beds of clay so often appealed to to shut out all surface water are a fallacious dependence, unless they are abso- lutely water-tight over great areas and under enormous pressure. It is too much to expect that a layer of clay sufficiently thick or impervious to water will always be found or that prospectors will go sufficiently far afield to secure for their wells a region of which the surface is above suspicion. The danger to be feared 90 TRANSACTIONS OF THE [JAN. 31, especially is that the flow of water from all directions towards the wells will, under the high pressure created by the pumps, follow only the larger pores and crevices underground, and by continually enlarging these, create in time a system of channels leading directly to sources of pollution. Such action would annul the filtering power of the soil, upon which so much depends where subterranean waters are used. The operation of the great system of gang-wells which now supplies about one-sixth of all the water used in Brooklyn illus- trates these principles upon a large scale. Seven million gallons of water are daily drawn from a system of 100 wells, varying in depth from 45 to 100 feet and covering a line about 400 feet in length. Such a yield corresponds to a total rainfall of 32 inches a year upon 3,000 acres, or roughly represents the same annual rainfall upon all of the land within a radius of 1} miles from the pumping station. Owing to the sudden demand for this water, the soil waters must be continually drawn downward in the vicinity of the pumps, and the nearer regions must be more effectually drained than the more remote. The predicted consequences are abundantly realized. Shallow wells in the neighborhood are wholly or nearly dry since the pumping station has been opened. A swamp formerly existing about the station has been dried up. The subsoil of the Jewish cemetery 370 yards distant, which offers frequent opportunities for observation, is said by the sexton to be much drier than heretofore. The existence of filthy barnyards and open house drains close to the wells, and richly manured fields all around them, are suggestive features of the case. Chemical analyses of the water from these wells show an abundance of nitrates, the sure indicators of organic decomposi- tion. The gang-well system may be, under proper precautions, of great benefit to communities seeking new supplies of water, but it is open to abuses in its applications which render it hardly less safe in the long run than the ordinary well. From a very large number of analyses of the water of small driven wells made by myself, I am convinced that the causes of deterioration in such wells rest also upon the principles already outlined. 1887. | NEW YORK ACADEMY OF SCIENCES. 91 Mr. CHITTENDEN stated that litigation over patents had de- veloped the fact that driven wells were first used practically by the Union armies during the war of the rebellion. The subject was further discussed by Pror. J. J. STEVENSON, Mr. CHITTENDEN, Mr. MERRILL, and the CHAIRMAN. February 7, 1887. KEGULAR BUSINESS MEETING. The President, Dr. J. S. NEWBERRY, In the chair. Sixteen persons present. The Report of the CouNcIL recommended the acceptance of the resignation of Mr. John Townshend, which was adopted. Mr. A. P. BJERREGAARD read a paper : REPORT UPON THE PINK DOLOMITE RECENTLY OBTAINED NEAR MORRISANIA, WITH ANALYSIS. Discussion. Pror. D. S. Martin thought that the mineral had some of the characteristics of calcite, but should be regarded as a variety of dolomite, the latter name properly being generic. Dr. A. A. JULIEN said that there had been too much reliance upon chemical analysis alone; a microscopic examination of these dolomitic limestones shows a heterogeneous condition, grains of calcite being mingled in the mass. He thought that the mineral might be a mingled calcite and dolomite. Mr. BJERREGAARD said he had obtained little insoluble matter in dilute acid, less than five per cent. Dr. BRITTON suggested that the color might be due to manganese. THE PRESIDENT spoke of the characters of true dolomite, and 92 TRANSACTIONS OF THE [FEB. 14,. of the origin of the magnesian limestones, which he considered. organic sediments and not chemical deposits. The subject was further discussed by Dr. Brirron, Mr. CHAMBERLIN and the author of the paper. Mr. Apert A. Cary exhibited an amethyst geode from Honduras, the crystals being of good color, and associated with crystals of calcite. THE PRESIDENT stated that the new building to be occupied by the scientific and literary societies of Buffalo was being dedi- cated this evening ; and on motion of the Secretary it was voted to send a telegraphic message of congratulation to the Buffalo Society of Natural Sciences. February 14, 1887. STATED MEETING. The President, Dr. J. S. NEWBERRY, in the chair. Highty-two persons present. Mr. Witt1am E. Hippen stated that the chemical analysis of the “ Bielid”’ meteorite, from Mazapil, Mexico, gave the fol- lowing results : Tron, 91.26 Nickel, 7.84 Cobalt, 0.65 Phosphorus, 0.30 Masses of graphite and of troilite were also found in the meteorite. Mr. L. E. CHITTENDEN directed attention to the published accounts of earthquakes in Japan and in the Sandwich Islands which, according to the reports, must have occurred simul- taneously. PRESIDENT NEWBERRY spoke of the result of observations on the diurnal nutation of the earth, by M. Folie, communicated 1887. | NEW YORK ACADEMY OF SCIENCES. 93 to the French Academy of Sciences, at the session of January 3d, and reported in Nature of January 13th, 1887. This phenomenon establishes beyond a doubt the fluid state of the interior of the earth, and a relatively thin crust. Dr. JoHN S. WHITE read a paper on THE LANDSKIBET, OR VIKING SHIP, DISCOVERED NEAR GOKSTAD, NORWAY, IN 1880. (Illustrated with lantern views. ) Remarks were made by Mr. McDonatp, Mr. CHITTENDEN, and the PRESIDENT. February 21, 1887. STATED MEETING. Mr. L. E. CHITTENDEN in the chair. A large audience present in the East Lecture Room of the Library Building, Columbia College. The second lecture of the Popular Lecture Course was deliy- ered by Pror. JoHN K. REEs on THE GREAT TELESCOPES OF THE WORLD; THEIR CONSTRUC- TION, POWERS AND LIMITATIONS. (Illustrated with lantern views. ) Like all great inventions, the telescope may be considered the product of many minds. The inventor was one who worked out the proper combination of lenses, or mirrors with lenses. Long before the invention of the telescope, spectacle glasses or lenses had been made. In the 8th century a.D., magnifying spectacles for old people were commonly used. Seneca, who lived in the first century, tells us that, in his time, it was well known that when writing was viewed through a globe full of water the letters looked larger and blacker. This appearance must have attracted the attention of many persons before the time of Seneca. The natural result of such a discovery would be the invention of glasses to produce magnification. It is not 94 ; TRANSACTIONS OF THE [FEB. 21, strange, then, that we find the use of a simple magnifying lens extending so far back that we are unable to fix the date for its discovery. But, down to the beginning of the 17th century, no one seems to have thought of combining two lenses together, one in front of the other, soas to render distant objects visible. ‘There appears to be some uncertainty as to the name of the original inventor of the telescope. Undoubtedly, Galileo was the first to publish to the world the manner of making the instru- ment, and, furthermore, he was probably an independent inven- tor; but itis well known that he was not the original inventor. In the Archives of The Hague, quoted by Arago, we read that a spectacle-maker of Middleburg, named John Lippershey, ad- dressed a petition to the States-General on October 2d, 1606, in which he asked leave to take out a patent which should consti- tute him the only maker of an instrument capable of rendering distant objects visible, or which should confer upon him an annual pension, on the condition of not manufacturing the instrument for other nations. On the 4th of October, 1608, the States-General appointed a deputy from each province to experi- ment on the new instrument, which was about one foot and a half in length. On the 6th of October, the commission declared the instrument to be useful to the nation, but demanded that it should be made for two eyes instead of for one. On the 9th of December, Lippershey announced that he had solved the problem. A favorable report was made on the 11th, and the binocular instrument was declared a success. ‘‘Saturnus tells us that an unknown man of genius called on Lippershey and ordered from him a number of convex and concave lenses. At the time agreed upon the man returned and chose two lenses, one convex and the other concave, and placing them one before his eye and the other at some distance from it, drew them backwards and forwards without giving any explanation of his manceuvres, paid the opti- cian and left the place. As soon as he was gone Lippershey _ began to imitate the experiments of the stranger, and soon found that distant objects were brought apparently nearer when the lenses were placed in certain positions. He next fastened them to the ends of a tube, and lost no time in presenting the new instrument to Prince Maurice,of Nassau.” OO ——— 1887. | NEW YORK ACADEMY OF SCIENCES. 95- According to another version, Lippershey’s children were play- ing with the lenses, when one of them, happening to place a convex lens in front of a concave lens, was greatly surprised to see the vane of the clock-tower of the Middleburg Church appar- ently brought nearer. Lippershey’s attention being called to the fact, he tried it, and, working out the idea, he invented the first telescope. Metius, of Amsterdam, the discoverer of the ratio 345 (the re- lation between the circumference and the diameter of a circle): claimed to be the inventor. Jansen and Baptista Porta and others disputed for the honor. Inasmuch as the first telescopes were at once seen to be of great value in wars, it was attempted to keep the invention a secret. Galileo heard, through letters, that an instrument had been in- vented which rendered distant objects visible, but he obtained no account of the construction. He, however, on this hint, made a telescope after several trials. The highest magnifying power which Galileo used was nearly 30 diameters. He was the first to direct the telescope heavenward. He saw the spots on the sun, the moons of Jupiter, the mountains in our moon, the handles of Saturn, the phases of Venus, and made other inter- esting discoveries. Kepler suggested for the single biconcave lens near the eye, used by Galileo and others, a double convex lens, which gave a larger field. This combination is called the ‘‘ Astronomical eye-piece.” It inverts the objects looked at. It is foreign to my purpose to enter into the details of the construction of a telescope. You all know that the power of a telescope to magnify an object looked at depends upon the focal lengths of both object-glass and eye-piece. It is the ratio of the first to the second. If, then, our object-glass forms an image of the moon at a distance of 100 inches from the centre of the glass, and we view that image with an eye-lens whose focal length is one-quarter of an inch, we obtain an image in the field of view which is magnified 400 diameters. We can, therefore, increase our magnifying power either by making the focal length of the object-glass greater, or that of the eye-lens less, or by doing both. With a given object-glass we can, theoretically, 96 TRANSACTIONS OF THE [FEB. 21, make our magnifying power as great as we choose. If, in the case cited, we use an eye-lens with a focal length of say ;4,th of an inch, we obtain a magnifying power of 100 x 100, or 10,000 diameters. ‘‘ But in attempting to do this a difficulty arises with which astronomers have always had to contend, and which has its origin in the imperfection of the image formed by the object-glass. No lens will bring all the rays of light to abso- lutely the same focus. When light passes through a prism the various colors are refracted unequally, red being refracted the least, and violet the most. “‘It is the same when light is refracted by a lens, and the consequence is that the red rays will be brought to the farthest focus and the violet rays to the nearest, while the intermediate colors will be scattered between. As the light isall not brought to the same focus, it is impossible to get any accurate image of a star or other object, at which the telescope is pointed. The eye sees only a confused mixture of images of various colors. When a sufficiently low magnifying power is used, the confusion will be slight, the edges of the object being indistinct and made up of colored fringes. When the magnifying power is increased, the object will indeed look larger, but these confused fringes will look larger in the same proportion, so that the observer will see no more than before. This separation of light in a telescope is called chromatic aberration.” The early astronomers found no way to get rid of this diffi- culty. They discovered, however, that they could diminish the trouble by increasing the focal length of the telescope, and thus making the image larger. An object-glass, say, of 5 inches diameter, with focal length of 60 feet, would give no more con- fused image than the same object-glass with a focal length of 6 feet. ‘The image formed by the first would be ten times as large as that formed by the second, so that a low power of eye-lens could be used, and hence the confused fringes produced the less disturbing effect with a given eye-lens, the greater the focal length of the object-glass. In this way Hughens, Cassini, Hevelius, Blanchini and other astronomers of the 17th century were able to obtain quite high magnifying powers. These astronomers made telescopes of 100 to 150 feet in focal length, 1887. ] NEW YORK ACADEMY OF SCIENCES. 97 and one man finished an object-glass whose focal length was 600 feet. Cassini mounted the objective on the top of a long pole free to move, while the eye-piece was moved along near the ground un- til the object-glass and eye-lens were brought into line with the star to be observed. The tube of the telescope was dispensed with. Hevelius connected his object-glass and eye-piece by a long pole. Newton, in his treatise on Optics, declared that the improvement of the refracting telescope was ‘‘ desperate,” and he turned his attention to reflecting telescopes. But an English optician, named Dolland, about the middle of the 18th century, discovered a remedy. He found that by a combination of lenses of crown and of flint glass he could obtain an almost colorless image at the focus. This, indeed, was a grand victory, and at once enabled the opticians to construct telescopes of less length. They could now put more of the magnifying power in the eye- piece, and have a telescope of such a length as could be com- fortably handled. ‘Telescopes, made of such a combination of lenses as we have alluded to, are called ‘‘ achromatic.” As larger and more perfect achromatic telescopes were made, a new source of aberration was discovered, no practical method of cor- recting which is yet known. It arises from the fact that flint glass, as compared with crown, spreads out the blue end of the spectrum more than the red end. The consequence is that two lenses cannot be made so as to entirely get rid of the color. “In a small instrument the defect is hardly noticeable, the only drawback being that a bright star or other object is seen sur- rounded bya blue or violet ring formed by the indigo rays thrown out by the flint glass. If the eye-piece is pushed in so that the star is seen, not as a point, but as asmall disc, the -centre Of this disc will be green or yellow while the border will be reddish purple. But, in the immense refractors of 2 feet aperture and upwards, this ‘secondary aberration,’ as it is called, constitutes the most serious optical defect.” Some think that no art can cure this defect. Many methods have been tried, all without much practical value. The defect may be lessened in the same way that the astronomers of the 17th cen- tury lessened the effect of ‘‘chromatic aberration,’—viz., by 98 TRANSACTIONS OF THE [FFB. 2t, lengthening the telescope. But the lenses of the 17th century were very small and light, compared with the large lenses now made. And it would be very difficult to mount rigidly a tele- scope 100 feet long, carrying one of the large modern lenses. Newcomb considers that, in the great refractors of recent times, the limit of optical power for such instruments has been very nearly attained. Many of the telescopes of the older astronomers had object- glasses (of crown glass only) of from $ an inch to 1 inch in diam- eter. Some were larger. After Dolland made his discovery, the great difficulty experienced in obtaining discs of flint glass of the required degree of purity prevented the making of any large telescopes till the beginning of this century, when Guinand dis- covered a process of making large discs of glass free from air- bubbles and strive, and of equal density throughout. Most of my audience understand that the object-glass of a refracting telescope is the ‘‘ vital part, the construction of which involves the greatest difficulty.” Given the object-glass, and the rest of the telescope can be quite easily made. And in the making of the object-glass there are two perfectly distinct processes. First, there are the beautifully clear discs of crown and of flint glass to be obtained. ‘This is the work of the glassmaker. And then these discs have to be ground and polished, so as to form perfect lenses which will give uncolored images and bring all the rays of light to one focus. This is the task of the optician. Both require extraordinary skill. Few men have it. About the beginning cf this century the ‘‘ English Board of Longitude” offered a considerable reward for bringing the art of making flint glass for optical purposes to the requisite perfection; but it led to no important discoveries. ‘The Academy of Scien- ces of Paris offered prizes in vain for this object, and it remained for a man, not distinguished by education nor a glassmaker by trade, M. Guinand, of Switzerland, to have the honor of arriving at the solution of the difficulties. Pierre Louis Guinand was one of those geniuses who seem to have great intuition and immense perseverance. He is said to have had no knowledge of optics, yet when quite young he con- structed a small telescope equal to the best of his time. He soon 1887. ] NEW YORK ACADEMY OF SCIENCES. 99 turned his attention to producing glass discs of the requisite purity for making large telescopes. ‘‘ He obtained some flint glass from England, but this was not always perfectly pure. He melted it anew, but did not obtain satisfactory glass.” He then erected an establishment in which he constructed with his own hands a very large furnace, and commenced the manufac- ture of glass; and finally succeeded in obtaining pieces large enough for telescopes. He afterwards discovered a method of softening pieces of perfectly pure glass for the purpose of giving them the form of adisc. In 1805 he was employed by Utz- schneider to assist in making object-glasses at the celebrated optical estabishment near Munich. Here he worked with Fraun- hofer, but in a subordinate capacity. He had sold his secret with his service. After remaining here some nine years he re- turned home, drawing a pension from the Munich establishment so long as he did not reveal the secret or himself make object- glasses. He could not long resist the temptation, and soon gave up the pension to undertake the manufacture of larger discs than any he had previously made. In 1823 he produced a disc 18 inchesin diameter. In 1824 he exhibited at the exposition in Paris a grand achromatic object-glass which excited the admiration of the king, and Guinand was invited to come to Paris to live. He, however, was in feeble health and old. He died in 1825 at the advanced age of nearly 80 years. Many think that Fraunhofer owed to Guinand much of his fame gained in making large object-glasses. After the death of Guinand, his widow and one of his sons set up works in Switzerland. The other son was introduced to Bon- temps of Paris. They succeeded in producing good flint glass in discs of from 12 to 14 inches in diameter. In 1848 Bontemps accepted an invitation to unite with Messrs. Chance Bros. & Co., of Birmingham, England, in their efforts to improve the quality of glass. They have succeeded in producing some very large discs, notably the ones for the Newall telescope of 25 inches, and also the discs for the great Washington telescope of 26 inches diam- eter. The establishment of Guinand at Paris is now conducted 100 TRANSACTIONS OF THE [FEB. 21, by Feil, a grandson of P. L. Guinand. Feil made the discs for the great Austrian refractor, 27 inches in diameter. He also made the discs for the Princeton telescope, and furnished the discs for the great Russian telescope of 30 inches diam- eter, and those of 36 inches for the Lick Observatory of Cali- fornia. The process of making these large discs seems to be well un- derstood by Messrs. Chance and Feil, so that the only difficulty in getting the large discs is the long delay. The Russian discs were received by the opticians (the Clarks), who do the polish- ing, in about two years after being ordered. The flint disc for the Lick telescope was ready in about one year, and the crown was nearly ready in nine months after, but was broken in the handling. Newcomb thinks that the secret of the manufacture consists principally in the constant stirring of the molten glass during the process of making. The reason why the glass-makers require so long a time to make the large discs may be understood from the following ac- count: *‘As optical glass is now made, the material is constantly stirred with an iron rod during all the time it is melting in the furnace, and after it has begun to cool, until it becomes so stiff that the stirring has to cease. It is then placed, pot and all, in the annealing furnace, where it is kept nearly at a melting heat for three weeks or more, according to the size of the pot. When the furnace has cooled off the glass is taken out, and the pot is broken from around it, leaving only the central mass of glass. Having such a mass, there is no trouble in breaking it up into pieces of all desirable purity, and sufficiently large for moderate-sized telescopes. But when a great telescope of two- feet aperture or upward is to be constructed, very delicate and laborious operations have to be undertaken. ‘The outside of the glass has first to be chipped off because it is filled with im- purities from the material of the pot itself. But this is not all. Veins of unequal density are always found extending through the interior of the mass, no way of avoiding them hay- ing yet been discovered. ‘They are supposed to arise from the 1887. | NEW YORK ACADEMY OF SCIENCES. 101 materials of the pot and stirring-rod, which become mixed in with the glass in consequence of the intense heat to which all are subjected. ‘These veins must, so far as possible, be ground or chipped out with the greatest care. The glass is then melted again, pressed into a flat disc, and once more put into the an- nealing oven. In fact, the operation of annealing must be re- peated every time the glass is melted.” Annealing consumes two months each time for the large discs. ‘‘ When cooled it is again examined for veins, of which great numbers are sure to be found. The problem now is to remove these by cutting and grinding without either breaking the glass in two or cut- ting a hole through it. If the parts of the glass are once sep- arated they can never be joined without producing a bad scar at the point of junction. So long, however, as the surface is unbroken, the interior parts of the glass can be changed in form to any extent. Having ground out the veins as far as possible, the glass is to be again melted and moulded into proper shape. In this mould great care must be taken to have no folding of the surface. Imagining the latter to be a sort of skin inclosing the melted glass inside, it must be raised up wherever the glass is thinnest, and the latter allowed to slowly run together beneath it. ‘“‘If the disc is of flint, all the veins must be ground out on the first or second trial, because after two or three mouldings the glass will lose its transparency. A crown disc may, however, be melted a number of times without serious injury. In many cases—perhaps the majority—the artisan finds that after all his months of labor he cannot perfectly clear his glass of the noxious veins, and he has to break it up into smaller pieces. When he finally succeeds, the dise has the form of a thin grind- stone two feet or upward in diameter, according to the size of the telescope to be made, and from two to three inches in thick- ness. The glass is then ready for the optician. ‘* The first process to be performed by the optician is to grind the glass into the shape of a lens with perfectly spherical sur- faces. ‘The convex surface must be ground in a saucer-shaped tool of corresponding form. It is impossible to make a tool per- fectly spherical] in the first place, but success may be secured on 102 TRANSACTIONS OF THE [FEB. 21, the geometrical principle that two surfaces cannot fit each other in all positions unless both are perfectly spherical. The tool of the optician is a very simple affair, being nothing more than a plate of iron somewhat larger, perhapsafourth, than the lens to be ground to the corresponding curvature. In order to insure its changing to fit the glass, it is covered on the interior with a coating of pitch from an eighth to a quarter of an inch thick. This material is admirably adapted to the purpose because it gives way certainly, though very slowly, to the pressure of the glass. In order that it may have room to change its form, grooves are cut through it in both directions, so as to leave it in the form of squares, like those on a chess-board. ** Jt is then sprinkled over with rouge, moistened with water, and gently warmed. The roughly ground lens is then placed upon it, and moved from side to side. The direction of the motion is slightly changed with every stroke, so that after a dozen or so of strokes the lines of motion will lie in every direc- tion on the tool. This change of direction is most readily and easily effected by the operator slowly walking around as he polishes, at the same time the lens is to be slowly turned around either in the opposite direction or more rapidly yet in the same direction, so that the strokes of the polisher shall cross the lens in all directions. This double motion insures every part of the lens coming into contact with every part of the polisher, and moving over it in every direction. Then whatever parts either of the lens or of the polisher may be too high to form a spherical surface will be gradually worn down, thus securing the perfect sphericity of both. ‘* When the polishing is done by machinery, which is the cus- tom in Kurope, with large lenses, the polisher is slid back and forth over the lens by means of a crank attached to a revolving wheel. ‘The polisher is at the same time slowly revolved around a pivot at its centre, which pivot the crank works into, and the glass below it is slowly turned in the opposite direction. Thus the same effect is produced as in the other system. ‘Those who practise this method claim that by thus using machinery the conditions of a uniform polish for every part of the surface can be more perfectly fulfilled than by ahand motion. The results, 1887. | NEW YORK ACADEMY OF SCIENCES. 103 however, do not support this view. No European optician will claim to do better work than the American firm of Alvan Clark & Sons in producing uniformly good object-glasses, and this firm always does the work by hand, moving the glass over the polisher and not the polisher over the glass.” Little imperfections are sure to exist after the first polishing. It is in the nice correction of these that the great skill of the optician is shown and much time is consumed. The American firm of Alvan Clark & Sons enjoys the reputa- tion of being the best opticians in the world for polishing large lenses. When the Russian government decided to construct a telescope that would surpass in size the great Washington telescope of 26 inches diameter of object-glass, Otto Struve, the director of the Imperial Observatory, was commissioned to make an examina- tion of the optical workshops of the worid to discover where the best object-glass makers could be found. After he had made a thorough examination in Kurope and in this country, he gave the contract to the firm of Alvan Clark & Sons. This great object-glass 30 inches in diameter is now completed. When the Russian glass was contracted for, the trustees of the Lick Ob- servatory in California ordered an object-glass of 36 inches aper- ture—so that we still have in the United States the largest refracting telescope in the world. I have dwelt upon the object-glass of a great refracting tele- scope because of its vital importance. We will have some expla nations to make in regard to mountings, etc., when at the close of the lecture we throw on the screen several pictures to illus- trate our subject. As we have previously stated, Isaac Newton, in the latter part of the 17th century, believed that there was no remedy for the defects in the refracting telescopes as then made, and he turned his attention to reflecting telescopes. Now it is well known that when parallel rays of light fall on a concave mirror they will all be reflected back toa focus, there forming an image of the object from which the rays emanate. The form of this concave mirror must be such that a section of it cut by a plane parallel to the length of the telescope will be a parabola. The image formed 104 TRANSACTIONS OF THE [ FEB. 21, will be made up of all the rays—there will be no such thing as. chromatic aberration. Thus if a mirror could be made and would continue of the true parabolic shape, the great and des- perate difficulty in the way of improving the telescopes might be removed. In the time of Newton, the reflecting telescopes, however, did not excel the long refracting telescopes. Even after Dolland’ discovery, the great difficulty met with in obtaining pure glass made the earlier short achromatic telescopes not much better than the long instruments. But in the latter part of the 18th century a genius arose who solved the problem of the construc- tion of large mirrors. History tells us that ‘‘ William Herschel, in 1766, was a church organist and teacher of music, of high repute in Bath. He spent what little leisure he had in the study of mathematics, astronomy and optics. By accident a Gregorian reflector two feet long fell into his hands, and turn- ing it to the heavens, he was so enraptured with the views pre- sented to him that he sent to London to see if he could not purchase one of greater power. ‘The price named was far above his means. He resolved, then, to make one for himself. After many experiments with metallic alloys, to learn which would reflect most light, and many efforts to find the best way of pol- ishing his mirror, and giving it a parabolic form, he produced a five-foot long (Newtonian) reflector, which revealed to hima number of interesting celestial phenomena, though, of course, nothing that was not already known.” He determined, then, to make the largest telescope that could be made, and after many failures, he produced a telescope hav- ing a mirror two feet in diameter and 20 feet long. At this time, 1781, he discovered the planet Uranus. His fame coming to the ears of the king, George III., that monarch gave him a pension of £220, that he might devote his life to the study of the heavens. He now accomplished his greatest work by mak-. ing a reflector four feet in diameter and forty feet long. With this he discovered two new moons of Saturn. It was not until 1842 that another great step was taken in the direction of increasing the power of the reflecting telescopes. Then the Earl of Rosse, of Parsonstown, Ireland, constructed 1887. | NEW YORK ACADEMY OF SCIENCES. 105 (using steam machinery for grinding and polishing) a great mirror, six feet in diameter, the tube being fifty-four feet in length. The telescope has not done as much work as was ex- pected, owing to the bad climate of the region where it is placed. It has been said that there are only afew hours in the year when the telescope can be used with its greatest efficiency. Since 1842 a considerable number of large reflecting telescopes have been made. But asa general rule (though silvered glass mirrors have been substituted for those of metallic alloy), the reflectors have not given as much satisfaction as was to be ex- pected. The large ones are more difficult to handle; the mirror tarnishes readily, and has to be frequently resilvered, and the alternations of heat and cold and of flexure produce a distortion of the curve which makes the mirror focus badly. These diffi- culties are so troublesome that refractors are usually preferred. The following table gives the location, character and aperture of the great telescopes of the world. SIZE OF PRINCIPAL TELESCOPES IN THE WORLD. Refractors. Owner and Location. Constructed by. Aperture. Remarks. Lick Observatory, Cal., A, Clark & Sons, 36 «sin, Pulkova, Russia, A. Clark & Sons, 30 «6** Finished in May, 1838. Yale College, A.'Clark & Sons, 28 ‘* Constructing. Littrow, Vienna, Grubb, Rafe AGC University of Virginia, A. Clark & Sons, PAO oat Washington Naval Obser- vatory, A. Clark & Sons, BON Gateshead, England, Cooke, Of Ls Princeton, N. J., A, Clark & Sons, 25, .f5 Buckingham, London, E’d,Buckingham, Palle © aa University of Chicago, A. Clark & Sons, alts 7G Strasbourg, Merz, 1S 28 Private Observatory, Buf- falo, Fitz. Se «% Warner Observatory, Ro- chester,’ Clark & Sons, 1G s® Washburne Observatory, Madison, Wis., A, Clark & Sons, 15.50 * 106 TRANSACTIONS OF THE Owner and Location. Constructed by. Aperture. Harvard College, Merz, 14.95 *¢ Pulkova, Russia, Merz, 14,98 ** Lord Lindsay, Dun Echt, Grubb, Hoy Royal Society, near Lond.,Grubb, Loewe Downsede College, Bath, 14.5 * Markree Castle, 1A es Oom, Lisbon, Merz, 14 Fr. in. C. H. F. Peters, Clinton, Spencer, 13.5 in. Boss, Albany, Fitz. 1} e GSC Columbia College Observ’y, Rutherfurd & Fitz,13 Allegheny Observatory, Pa. Fitz, 1 a Ann Arbor, Mich., Fitz, 1235: 5 Christie, Greenwich, Merz & Simms, 12.25 *s Vassar College, Fitz, reworked by Clark, Ol Pritchard, Oxford, Grubb, 12.25 ‘° Glasgow, U.S., A. Clark & Sons, 12.25 <* Paris, Secretan & Eichens,12 Fr, in. Littrow, Vienna, A. Clark & Sons, 12 in. Adams, Cambridge, Cauchoix, 1D: White, Brooklyn, N. Y., Fitz, a Ball, Dublin, Cauchoix, 12 o\<5 se) H. Draper, Jr. New York, A. Clark & Sons, ibe Main, Oxford, Cauchoix, TOTES (2) Pritchard, Oxford, Grubb, Up Os Cincinnati, Merz, i OLS Bothkamp, Germany, Schroeder, Th By eee Cordova, S. A., Fitz, TBs Munich, Germany, Merz, 1h es Copenhagen, Denmark, Merz, ie a Middletown, Conn., Clark & Sons, a And many others. [FEB. 21, Remarks. ‘ Destroyed by fire in 1867. Photographic lens attach- able. Pre- sented to Co- lumbia Col- lege by Mr. Rutherfurd in Dec. 1883. 1887, ] NEW YORK ACADEMY OF SCIENCES. 107 Reflectors. Owner and Location. Constructed by. Aperture. Remarks. Lord Rosse, Birr Castle, Rosse, 6 feet, William Herschel, Slough, W. Herschel, ea Out of use. {Since de- Lassell, Liverpool, etc., Lassell, 4 “ ) — stroyed. Ellery, Melbourne, Grubb, 4. Paris, Martin, Eichens. Ce Silvered glass. Lord Rosse, Birr Castle, Rosse, 36 in. Silvered glass. Common, England, 36 ¢ Tisserand, Toulouse, . Foucault, 32.4 < Stephan, Marseilles, Foucault, Eichens, 31,5 EP raper, nr. N.Y. H. Draper, 28 ** Silvered glass. Lassell, Maidenhead, Lassell, 24. ‘* Metal. W.& H. Herschel, Slough, Several mir- and C. G. H., W.& J. Herschel, 18 ee rors. H. Draper, nr. N. Y, H. Draper, 15 a M’Lean, Tunbridge Wells, With & Browning, 15 s Pritchard, Oxford, De La Rue, 13 £6 Worthington & Baxendell, Manchester, With & Browning, (?)13 rs And many others. Note.—The object-glass of the Lick equatorial is to cost, $52,000 00 Photocraphiclens' of crown! class: «siecle < cesses cslee vols 13,000 00 MoOuUNbIN oO TElLESCOPOM crlacre ciefel= eels steele elelieis civ ei cie eisietoice 42,000 00 Womerand MAachineryjccisssss.-.... 40 PL OUMINGO Viner oars co.cc ovate 130 Birds, desc. of (title)...... 111, 139 ROAESPACINE settee eens < 6 114-118 Bridge construction....... 148-160 PAGE Bridges, Historic.......... 148-160 PSTONZILC saat Ric soe as tote. hee 76 Brooklyn aqueduct........... 82 BS yalAWSis Sx heels suet << 1, 2,58, 66 Cabin Creek meteor...141-146, 166 @achalonersce eases sae oe 112 Calcite: = s:ccerteniciccos 91, 92, 118, 130 Cambrian formation.......... 113 Carbonic acid, liquid.......... 35 Carboniferous fishes...... 137, 1388 limestones. 2.0500 46 137, 188 Chalcedonyz.-se5--sass2 <=. 122-124 Chemical purifica. of water. .52-54 Chromite in meteorite...... 76, 162 Cobalt in meteorite. .......... 92 Color of Triassic rocks... 3... 125 Columbia Coll. Centen....113, 129 Copperas, on Staten Island.... 16 Coral Tectia. 25 «fea see lew > 32 Corundumys. eee eee 6-11 Cretaceous, of Staten Island.. 16 Cristi Ol, Partha: . aarcie cis 28-33 fexability Of-,.).52:..<< 32, 33 thickness:of -:-..... 28-30, 27 Desc. of new Titanichthys..... 164 Devoniannol Ne Juss oes 59 Diamond! from-Ny Cees... a. 39 Disease germs........ ert On Dolomite, pink. .- = s/s: 39, 91 Drifts clacialleracncccssoes 12; 18 pre-flacialenn cetera alli. als: Driven-wells) ses... ees 77-91 patente for faced ees ee 91 184 PAGE Barth) Crustiolereer ener 28-33, 37 heatiol einen Soto 20-22 state of interior, 21, 22, 29, 32, 33 Earthquakes.. ...18-35, 36-39, 65 bibliography of.......... 34-35 CAUSE Obs sane ee cence 33, 38 CRPIOSIONS: ooc.2en cs ease oe 2% FAMOUS ove ese ote e aioe ee. 36-87 LOCUS Olachlone- fete eee 26 frequency of... .24, 34, 36, 37 in gapan,iete.. Utes ewes 92 NECOTOOL jo. seen ee 24, 25 Election of Officers........... 110 Elephant’s tooth,............. 59 ‘* Elizabeth Thompson Science BUNGE a miei c basic 108 Evolution of Head............ 135 Ix Chares 7%... ciekwanceuice 167-182 Expeditions to cll gd ee, ee See 60-65 Exploration of America......60-65 Famous bridges ........... 155- ue Feldspar in Staten Island..... Pultrahion.. j.'s «cise 43-48, 54- 58 Fishes of L. Carboniferous, 137, 138 OL PIAS. Sc asey eet 125, 127-128 Hootprints, Triassic: ...- 4... 125 Kossils,Devonian,-c.. -rihiee 59 WRIASSIC.. sani Jaserine 124-128 Fossil fishes, Carboniferous... 137 Wevonianye sy atest tae ore 59 UPIDSSIG! eee eaeeies re 127, 128 Fossil plants, Cretaceous. .... 16 DOVOnTAN 6. wie 'sidscwievds dear 59 TPASSIC as yak kee car 125, 126 Galena from N. Y. City....41, 130 Geological Magazine.......... 164 Geologic time, length of...... 41 Glacial drift on Staten Island, Te My ills; drift in India: ... cade sess 41 CNOGH erie og ee Sate eee: fe Biniage J eee ght. eee dee 2 Gags dises sik. \ oc bie eo sae ae 98- 103 Gold, of Georgia.......:. 42, 60-65 ornaments from Florida, 40, from Central America.... 40 Graphite, in meteorite ....... 92 Greenavitey foo c hs. eae 130 Growth of Vinegar plant. ...66—70 GENERAL INDEX. PAGE Gyrating bodies........... 131-134. GyToOscope {.c0.\.s.ceenoeee 131-133 Heart of Africa (title)......... 165 Heat, of earth. ...20-22, 29, 32, 33. Hiddenite,.......2... eee 2, 73 Historic Bridges........... 148-160 History of Academy...... 146, 147 Hollow quartz crystals. . 122-124 EHydrophanes:....5.< 2 she ae 112 Timenite:,j.s2. - 118 WETSCOWAGE ccc ccc eels css cial 3, 39 Natchez Indians 42, 60-65 National Museum............. 166 Nickel, in meteorite.......... 92 INGUUSTOTDISS cc) os .6 clase Saaes sles 60 Nutation of Earth. .....92, 138, 134 secular changes........131-134 ING Yo MimeraliClub?..- ccs eec 160 ODSIGIANE vac. siete eye's, aieie alors 122 Officers, election of........... 110 reports of (see contents) GINS OCIASO: cite cis sos. sialeiccelenie'ey« UE Olivine, in meteorite, 73, 74, 76, 162 Oxyeen, In Water. ......:..- 48-52 Patents for driven-wells.. ... 91 Pectolite hammer............ 111 EHO COG YAM ertetee)stasarec sier cies 'e. s= 49 Phosphorus in meteorite.. .. 92 Plants, Cretaceous............ 16 EPrIASSI Gee ele oss) 32/5 125, 126 Powder-mill creek meteorite, 161, 162 Precipitation, to purify water, b PAGE Pre-glacial drift...........:- 16-18 Print, Mr. RUFUS... .25~ 520% 41 Erochlarite :..:.... 95s dee 130 Purification of water........ 42-58 EPL.