lhabo vel efele # brent peen * Ut ane . Navi winrereiatnletelety™wteretep etree wuts ss ; peret: : a iesaiele wives iisreie, rerete serene mir donde int rere sandisk inert 40> ithe edie ° . ; a 5 7 ¥ eins Abarat ettideh athe A te dnd sips tain ve Shak dhs eal aa ia ith 5 de de ce tah tide Ba AL AA RAAI Rhee ak Adee ee ee A CNT PET ORI OEE POLES OT Perr ew (86 Ea Se Fee PTE BEL CEE EE we TE ET TE HEE EEE ET OEE TE thahahethdb-tedthan ti At fwiwte he ey vey wel ae ————— srs doavalts bdoainth dL toah pth hdd : rere ae ity thigh tet J . : r ; ; ‘i - Seleieiy ene vite re J . a Q > bs a 18! Wee ieee WORE E SKY whee € an eer wee PEW ee Pere e FUE EE ENS CIN NY F Py ew fe As OWT Hele grew vverewery yes veer enh wallndy od Ped pb ee ek dath-dive Lthdbeht bebe hs 0 Pernt YOR i apmunnedoe os eS yi teh Op ‘ : \ é 5 7 NGS ; baie Cy Pan eat s og ral Z AA he ie ry - . . 3@@ 4 aif 1; » 12the | a : aviest wt 273" o < . Ll Aslalala Ht =. Aa MT \, fe ~e iat teres eM Wage rl pect : poceeean Mead} Pty Lee mye Merwe! AG Ue Tut Tho e1vard gern ear nenar tr ftt C-eleee 6 Pails PL Banorent \Syaia! me if evap tip alll ececann ELLE LEG ipy covetiprneg (lll COVA NAAT aa rs CON ea lai | | | pie balatatets sll TPaAatetaayttte no Weta, eietal | | Myiin. ie wy} @: ft ect enn rreneet TCT | ii b | Ws I 34 8 4eqne | inediia os. | SELLE Ben mtn ve" Mone =) nig a wiuiiibg Yi | byl | ind d aa oe na | sey " inte Hh ahr me * 4 ; o wed ia i “y i 7 abit \ 4. bey A nett Hone 4 het wy) 45 m4 Sig 4 ESB &X WS : tT the vi <,* S ASA AAA | peel J ! hit a) Ath 3 1 Ts | PE sa Wak A Ll {i a i Pee CL SUGGe J : ner Nae NWR SN Ea then conte rcmme Cece cost WUT TU ge Nl a scant NARANIT oe w . v2 30) 4 an a “ith Wt meee A as tm bs Sa ah NAAR. rT] oun we ae neg’ wert 7 nalvargiee | : we “ tL) A mei } ‘ eee ie Mae oe Le | avtiive | Pk a MY aE HH a : ane Ss be Tt F Mm 4 Ft i 4 & rh TLL teks aes ener ty lbialalale | AR erty Spt vey ee TIT + as |, ae +a bp © a: “{ y ‘ pia) AT Ad ei ee 2 HPT bbe Wy ¢ 4 Ss al “it wren gen poe ee aad Rabi | eee ie ny Ree sy, alae j ¥ heads ox eee 4 Zz 4 7 e-* we Ww! lq bahbi is u : *epe P) “Fe . ad QE SP Se B09 rag jai maaan. AN dad yn dtiny rm) Attan (fir wh fr [poner dase en vl ik eee Nay 1 Meh os TS 4 | ! ‘ wf gene or he! Gis i we. ae abs f L ’ s po, . Ohne SMa SL Myivee be Nees viens N q rw a Ake Fan = orl lalelalale Jan, 8 Amos. PASE N eee, TT led AN Solon alan ant hh. ale b | 5 “ey a oni 7 oer ~ ‘ ei Ps ‘> wi, M3 ptt! Nad sae wy ; oy ‘“ : 7 * ad 7 u |. | omg , Ks a : F 1 : nih ee hi hone ett led ume iscll, wd rT hd ean BON eb el a A OHAMS petty 8% eG) ¢ AY Aw, he? | Leedtoiiel ok] 2 alh PRIMA A HT peat liebe 1] 14 il ARRAY A ae*, Poh A Di SSWAy emia | te M UI » a eae & ; Css pi s Jo) ia NMA gE STREET HY Cg Hl “abtnnngiyidtingage CS SAar ss, TONY 114 Stet ale ' | ae xs Na lab | MAA Et TAK ‘a : Dy yes Wes, eg , Ae Whiner: AL MUL NAL ny Tn Wa ex LMR I AR "Vey, i <4 hak © w h) Mite SPU tie Oe yy Ke “© ene, hind bp ity LLL UHL it ee Pi Wace nee”. eG ey OE, Tans IO Ha a tL 4 . Was - zi y ro, . 4 \eteten, “q oe td AA apart Sahih reeeweun Pay ah i Pena pane 1) Ba ine iJ iv Pau phi SO a *. me 8k : Oe Ng AA. iy ad® ae," ¢s Stings, s & sss ap doy Wee : yoy ee s] Ad ao { : ; wh. e Red AR yp weiss Warateeines tdnapaN UAL) AA we: “bibbiale ee ae L NAnAnt reser | ot waren ot ot AAT” | aa TTL Hatt ierimsins MA Wis" TM | Fett Usevanthtettnty lta ora Bee ‘ S Lee ee cf iy, ’ vy x { » ‘ a p 4 IS : - N » : q ‘ WS rt z AB, ee “ Or: 3 ver, ee ‘ = SPR NRTN Eee. & ay Molal V Sty ayy raf ant nv Va Wak iy * < UN ADS Ae sSi t Se we at MA "5 Sta? ‘ i. ie hs | Y x abe gain “sUpsmanty. a) sella able ty 4 lola b veve ced ra] a NA. Pre vn WP hgh ' | Roy. “tian: aN \’ t ev v ae 7 oa v ¢ ~Ates, wee A TTIL | apethve phates saqenyoetbetn’ : LUTTE PUT eerie rete rusting RUN E MT hakda aak? MMU y UNI cat ea Se fat i Uae We THE AMERICAN JOURNAL OF SCIENCK. JAMES D. anp EDWARD 8. DANA. ASSOCIATE EDITORS Proressors JOSIAH P. COOKE, GEORGE L. GOODALE. AND JOHN TROWBRIDGE, or CampripeGs. Prorressors H. A. NEWTON anv A. E. VERRILL, or New Haven, Proressor GEORGE F. BARKER, or Putnaperpnta, THIRD SERIES. VOL. XLV._[WHOLE NUMBER, CXLV.] Nos. 265—270. JEAN Ne A © JUAN 1893: WITH VI PLATES. i SiG dGs ~A NEW HAVEN, OCONN.: J. D. & E. S. DANA. 1S Ove PRESS OF TUTTLE MOREHOUSE & TAYLOR, NEW HAVEN, C ny CONTENTS OF VOLUME XLV. Number 265. Page Arr. I.—The Age of the Earth; by CLarence Kine, With F JP Ulett sao ST ER Sly gp Yc) I Ope 1 I1.—Tertiary Geology of Calvert Cliffs, Maryland; by Gix- PSE MUEEL are isy 6 SMG! oar RONG 100 yes 9 “iuue —‘‘ Anglesite” associated with Boléite; by F. A. Genta 32 IV.—Preliminary Account of the Iced Bar Base Apparatus of the U. 8. Coast and Geodetic Survey; by R. S. NRTON OD WEAVE Dis Rag Seem ley eE op SF) aa ye UEN) 33 V.—Some Experiments with an Artificial Geyser; by J. C. (GTR AVTST NINERS BSL UNE Ae SOR la es ae tree AMA ys? fot ALD 54 VI.—Observations of the Andromed Meteors of November 23d-and- 27th, 1892= by EH. Ay Nrwron. 2 2.25232 61 Vil.—Pr eliminary Notice of a Meteoric Stone seen to fall at Bath, South Dakota; by A. E. Foorr. With Plate III 64 VII.—Appenpix—New Cretaceous Bird allied to Hesper- coments gel Os. C eel VEARSEL 54-62 5s a 2s pore Lea ea 81 IX.—Skull and Brain. of Claosaurus; by O. C. Marsu. Wine ilatesslaVeran dip Ve 22 8228) Jedd ote ye 83 SCIENTIFIC INTELLIGENCH. Chemistry and Physics—Influence of Foreign substances on the Form, the Size and the Purity of Crystals separating from a solution, RETGERS, 65.—Kesolu- tion of Lactic Acid into Optically active Constituents, PURDIE and WALKER: New element Masrium, RicHMOND and OFF, 66.—Freezing points of very dilute Solutions, Raoutt, 67.—Chemical Lecture Experiments, G. S. Newt: Color Photography, M. G. LippMAN: Infra red spectra of the Alkali Metals, B. W. Snow, 68.— Magnetic effect of the Sun upon the Earth, W. THomson: Sound and Music, J. A. ZAHM, 69. Geology and Mineralogy—View of the Ice Age as One Glacial Epoch, 70.—Pleis- tocene History of Northeastern Iowa, W. J. McGnez, 71.—Note on the paper in the November No. of this Journal on ‘* A New Oriskany Fauna in New York,” S. T. Barrett: Subdivisions of the Azoic or Archean in Northern Michigan, M. E. Wapsworta, 72.—Geological and Natural History Survey of Minnesota, N. H. WINCHELL: Final Report of the Pennsylvania Geological Survey, LrEs- LEY: Arkansas Geological Survey: Geological Map of Baltimore and its Vicin- ity: Devonian Fishes of Canada, A. S. Woopwarp, 73.—Nepheline Rocks in Brazil. O. A. Derpy: Panama Geology, M. Douvitie: Geological Map of Scot- land, A. GEIKIE: Quaternary Carnivores found on the island of Malta: Excava- tion by Glaciers: Chamberlin on the Glacial period, %4.—Mikroskopische Physiographie der petrographisch wichtigen Mineralien, von H. ROSENBUSCH: Gesteine de Kcuatonanische West Cordillere, M. BreLowsky: Chemical Contri- butions to the Geology of Canada G. C. HorrMAnn, 75.—Presence of Magne- tite in certain Minerals and Rocks. LiveERSIDGE: Manual of Qualitative Blow- pipe Analysis and Determinative Mineralogy, F. M. Enpricn, 76. Miscellaneous Scientific Intelligence—Geminid Meteors of Dec. 11, 1892: La Planéte Mars et ses Conditions d’Habitabilité, CamiLLE FLAMMARION, 77.—Investiga- tion of the Coral Reefs of the West Tndies, A. AGAssiz: Gelatine slides for lantern projection. W. J. WAGGENER: Transactions of the Texas Academy of Science: Die Klassiker der exakten Wissenschaften, W. OSTWALD, 78.—Royal Society of London, 79. Obituary—JouN STRONG NEWBERRY, 79.—SIR RICHARD OWEN, 80, lv CONTENTS. Number 266. Art. X.—Isothermals, [sopiestics and Isometrics relative to Viscosity; by C. Barus..-5 22222... 2-6. 87 XJ.—“ Potential” a Bernoullian Term; by G. F. Brecker. 97 XII.—Datolite from Loughboro, Ontario; by L. V. Prrsson 100 XIII.—New Machine for Cutting and Grinding thin sections of Rocks and Minerals; by G. H. Witiams -.--__--- 102 XIV.—Stannite and some of the Alteration Products from theBlack Hills;'S: D:; by, WiwRs HhAppEN =e Saas 105 XV.—Occurrence of Hematite and Martite Iron Ores in Mexico; by R. T. Hiti; with noteson the associated leneous Rocks; by W. (Cross’i2 2!) . Nee ae tan eee 150 XX.—Lines of structure in the Winnebago Co. Meteorites and in other Meteorites; by H. A. Newron.-.-------- 152 XXI—Preliminary Note of a new Meteorite from Japan; by ERUA. (Warp ts ee ae ee eas Gy a ey ApprenpDrx.— X XII.—Restoration of Anchisaurus; by O. C. Marsa. (With: Blate Vl): 222c205 S228 Saris eee 169 SCIENTIFIC INTELLIGENCE. Chemistry and Physics—Re-conversion of Heat into Chemical Energy in the production of Gas, NauMANN, 155.--Temperature of Ignition of Electrolytic Gas, FREYER and V. MrysER: Electromotive Activity of the Ions, NERNST and PAULI, 156.—Separation of Precipitates at the Surface bounding Electrolytes, KUMMELL: Chemical Phenomena at low Temperatures, PrcTET, 157.—New Telephotographic lens. T. R. DALLMEYER: Oxygen for lime light, T. C. HEp- Wort, 158.—Interference of Electric Waves: Explanation of Hall’s phenom- enon, EH. LoMMEL: Mercury Voltaic arc, H. Avon, 159. Geology and Natural History—North American Fossil Mammals, 159.—Geology of the Eureka District, A. HAGUE, 161.—Geological Survey of Alabama, EH. A. Smit: Geological Atlas of the United States, Chattanooga sheet, Tennessee : North American Continent durmg Cambrian Time, C. D. Watcorr: Lafayette Formation, W. J. McGrEE: Origin and Nature of Soils, N. S. SHALER, 163.— Cambrian Fossils of New Brunswick, G. F. MartHew: Experiments in Physical Geology, E. ReyEr: Brief notices of some recently described minerals, 164.— Large Variations in the Metamorphosis of the same species, W. K. Brooks and F. 11. HERRICK, 166.—Morphologische Studien, K. Scoumann, 167. Miscellaneous Scientific Intelligence—Bulietin from the Laboratories of the State University of Iowa: Astronomical Journal Prizes: Ostwald’s Klassiker der Exakten Wissenschaften, 168. CONTENTS. Vv - Number 267. P Art. XXIII.—Diversity of the Glacial Period; by T. C. CHASMBER EIN: eer re Sok 2 Lelia lve Be Dee oe ate ied ey a ere iP age XXIV.—Specific Heat of Liquid Ammonia; by C. Lupr- STING SAC ul tise 5 DANRIR 2 2s yep ele ote ye et Re peed 200 XXV.—Stratigraphic relations of the Oneonta and Chemung formations in eastern Central New York; by N. H. MS ASRROING eee ee ee tate ee ae oe gi ONS LCR NG dN 203 XXVI.—Kstimates of Geologic Time; by W. Upnam__---_- 209 XX VII.—Notes on the Cambrian in Missouri and the Classi- fication of the Ozark Series; by A. WiInsLow __------- 2211 XXVIII.—A Short Cycle in Weather; by J. P. Haut --.- 227 XXIX.—Kilauea in August, 1892; by F. 8. Dope _._-_-__- 241 XX X.—Address delivered before the American Metrological Society, Dec. 30, 1892, by the President, Dr. B.-A. CE 00 Re ope AS enc bi Mr ACA Ted ie ON UM OE AY 246 SCIENTIFIC INTELLIGENCKH. Chemistry and Physics—Energy as a Dimensional unit, OStwaLp, 251.—Permea- bility of Precipitated Membranes, TamMann: Fluosulphonie acid, THORPE and KrrM An, 252.—Carbon di-iodide, Morssan: Photographic study of the movement of projectiles, F. NEESEN, 253.—New Species of Magnetic and Electrical Instruments, G. QUINCKE: Refraction of electrical waves by alcohol, H. O. G. ELLINGER: Absorption spectra, JuLius, 254.—Optical Indicatrix and the Trans- mission of Light in Crystals, L. FLErcHER: Text-book of Physics. largely exper- imental, EK. H. Haut and J. Y. Bereen, Jr. Theoretical Mechanics, J. SPENCER, 255. Terrestrial Physics—Gravity Determinations at the Sandwich Islands, E. D. PRESTON, 256. Obituary—FREDERICK AUGUSTUS GENTH, 257. vl CONTENTS. Number 268. Page Arr. XX XI.—Distance of the Stars by Doppler’s Principle; by (Ga WW: CoLuEs. JR... =. eee Se ee 259 XX XII.—Double Halides of Tellurium with Potassium, Ru- bidium and Cesium; by H. L. Wuetnr--_---.------- 267 XXXITI.—Tungstous Oxide—a new Oxide of Tungsten— associated with Columbous Oxide; by W. P. HeappEn 280 XXXIV.—Sodalite-Svenite and other Rocks from Montana ; by W. LinpeGreN, with Analyses by W. H. Mrenvitite_. 286 XXXV.—A Basic Dike near Hamburg, Sussex Co., New Jersey, which has been thought to contain Leucite by Jes ORME tes 2 2) ot Loe eh Se re ene 298 XXXVI.—Underthrust Folds and Faults; by E. A. Smirn_ 305 XXX VII.—The Cretaceous Formations of Mexico and their Relations to North American Geographic Development ; |e gil hee) Wee Dy op Oe ee png eS nae Sees Mas AL os 307 XXXVIIL.—Electrical Oscillations of Low Frequency and them lvesonance sm bivg Negi uiko PIN ess ae ete 325 XXXIX.—Determination of Iodine in Haloid Salts by the Action of Arsenic Acid; by F. A. Goocu and P. E. UROW.NING 2% 2 onde DR SR Oe Oe td tgs Soe rs EIS XL.— Radiation and Nigonaiton of ent by Leaves; by A. Gul MAYER) 2 ob eee ee pine parame. ete)" SCIENTIFIC INTELLIGENCKH. Chemistry and Physics—Improved Boiling-point apparatus for determining Molecular Masses, SAKURAT, 346.—Color of. the Ions, OStWALp, 347.—A fiinity- coefficients of Acids, LELLMANN and SCHLIEMANN, 348,—Reaction of Hydrogen with Chlorine and Oxygen, HarKER: Daily variation of Gravity, Mascart, 349.—Simple apparatus for the determination of the Mechanical Kquivalent of Heat, C. CHRISTIANSEN: Asymmetry in Concave Gratings, J. R. RYDBERG: Potential of Electric Charges, A. HEYDNEILER: Sensitive Galvanometer, H. FE. J. G. DuBois and H. RuBeNS: Experiments with Currents of High Frequency, A. A. C. SWINTON, 350. Geology—Correlation Papers, Neocene (Bulletin of the U.8. Geol. Survey), W. H. Dati and G. D. Harris, 351.—Michigan Geological Survey for 1891-2: Geological Survey of Missouri, 1892: Geological Survey of Texas, 1892: The Journal of Geology, 354.—Republication of Conrad's Works: Lines of Struc- ture in Meteorites, 355. Botany—Localization of the perfumes of Flowers, MESNARD: Botanical Prizes of the French Academy, 355.—How blanched seedlings can be saved, CORNU: Influence of moisture on vegetation, E. GAIN, 356. Astronomy—tTransactions of the Astr. Observatory of Yale University, 357.— Schreiner’s Spectral- Analyse der Gestirne, 358. Miscellaneous Scientific Intelligence—Observations in tlhe West Indies. A. AGASSIZ, 358.—Barrier Reef of Australia, W. SAviLLe-Kent: Logarithmic Tables, G. W. JonzEs, 362. Obituary—NIcoLaAs KOKSHAROV, 362. CONTENTS. vii Number 269. Art. XLI.—Deportment of Charcoal with the Halogens, Nitrogen, Sulphur, and Oxygen; by W. G. MixtEr..-- 363 XLII.—Note on some Voleanic Rocks from Gough’s Island, SouthyAtlantic:: byl.) EaRssOn 222 2222) ee 2s e380 XLIU.—Champlain (2) deposit of Diatomacez belonging to the Littoral Plain; by A. M. Epwarps-__--_.-..--..- 385 XLIV.—Refraction of Light upon the Snow; by A. W. AV VERTED Nort Ye eyes) Oia hy ye gil dS LS Rta eae 389 XLV.—Value of the force exerted by a current of Electricity in a circular conductor on a unit magnetic pole at its Cente yO ah. ¢ MOR TE ANID eee se sieruylialiays alee oimee yaa 392 XLVI.—Cookeite from Paris and Hebron, Maine; by 8S. L TRENT TOPE 0) 8 Ne Ua a IM ek raat LN ay ra 393 XLVII—Mineralogical Notes ; by S. L. PENFIELD ---.--- 396 XLVIII.—Infiuence of Free Nitric Acid and Aqua Regia on the Precipitation of Barium as Sulphate; by P. E. ESO WW/NEN Gs os seer She ek ieee ee a AN ake Lat oe 399 XLIX.—Rose-colored Lime- and Alumina-bearing Variety ommale tb ye We He HOBBS toss igh eed erat ee POs og 404 L.—The Magothy Formation of Northeastern Maryland; by Ded lod DING rs may pea ees hn ee gD OR eal Ser HR ola nee (7) LI.—Electrical Oscillations of Low Frequency and their ivesonancels Diy, Mish EA oe in (pais) S02 eA esa een 420 SCIENTIFIC INTFLLIGENCE. Chemistry and Physics—Properties of free Hydroxylamine, L. DE BRuYyN: Tri- sulphide and the Pentasulphide of Boron, Moissan, 430.—Oxidation of Differ- ent forms of Carbon, Wiesner: Rise of Salt-solutions in Filter paper, KH. FISCHER and SCHMIDMER, 431.—Chemical Inactivity at low Temperatures, R. PictEet, 432.—Berzelius und Liebig, Ihre Briefe von 1831-1845, 433.—Carl Wilhelm Scheele, Briefe und Aufzeichnungen herausgegeben von A. E. NORDENSKIOLD: Simple apparatus for measuring the Index of refraction of Liquids, H. Ruoss: Hlectromagnetic Theory of Color dispersion, H. von HELMHOLTZ, 434.—Penetration of thin metallic sereens by Phosphorescent rays, LeENARD: Representation of Equipotential lines due to a current flowing through a metallic plate, K. Lommen: Alternating Currents, F. BEDELL and A. C. CREHORE, 435.—Die physikalische Behandlung und die Messung hoher Temperaturen, C. Barus: Hilfsbuch fiir die Ausftihrung elektrischer Mes- sungen, A. HEYDWEILLER: Practical Physics, R. T. GLAZEBROOK and W. N. SHaw: Elementary Treatise on Physics, Experimental and Applied, KE. ATKIN- SON, 436. Geology and: Mineralogy—Additions to the Paleobotany of the Cretaceous Formation on Staten Island, A. HoLtick: Organization of the Fossil Plants of the Coal-Measures, W. C. WILLIAMSON, 437.—Fossil Plants as Tests of Climate, A. C. Sewarp: Flora Tertiaria Italica, A. MESCHINELLI and X. SQUINABOL, 438. —Correlation of Early Cretaceous Floras in Canada and United States, J. W. Dawson: New Teeniopterid Fern and its Allies, D. WHITE, 439.—Bryozoa of the Lower Silurian in Minnesota, EK. O. Utricu, 440.—Tertiary Mollusks of Florida, W. H. Datu: Petrographische Untersuchungen an argentinischen Graniten, J. RoMBEeRG: Phonolite in Great Britain: Catalogue of American Localities of Minerals, EK. S. Dana, 441.—Repertorium der Mineralogischen und Krystallographischen Literatur, 1885-91, P. Groru, 442. Miscellaneous Scientific Intelligence—Hodgkins Fund Prizes: Mechanics of the Earth’s Atmosphere. C. ABBE: Manual of Irrigation Engineering, H. M. WIL- son: Jean-Servais Stas, 442. Vili CONTENTS. Number 270. Page Arr. LII.—Electro-Chemical Effects due to Magnetization ; by G. O., Squimr. _....2555228252 222. LIII.—Nikitin on the Quaternary Deposits of Russia and their relations to Prehistoric Man; by A. A. Wrieut__ 459 LIV.—Rigidity not to be relied upen in estimating the Earth’s Age; by O. FIsHER.- 222-226-200 464 LV.—Treatment of Barium Sulphate in Analysis; by J. i. PHINNEY -..:.. 2: -.---:2epee ee eee 468 LVI.—Validity of the so-called Wallala Beds as a Division of the California Cretaceous; by H. W. Farrpanks.--- 473 LVII.—Nature of Certain Solutions and on a New Means of investigating them; by M. C. Lima: 1-2-2 as 25S2e = ees LVIII.—Mineralogical Notes; by A. J. MosEs_---_--. ._-- 488 LVIX.—Pentlandite from Sudbury, Ontario, Canada, with remarks upon three supposed new species from the same Region; by S.. LL. REnrigip 22229552) == 493 LX.—Notes on the Geology of Florida: Two of the lesser but typical Phosphate Fields; by L. C. Jounson ------ 497 LXI.—Electrical Oscillations of Low Frequency and their Resonance; by M. I. Purin._..-2:. <2) 22a 508 SCIENTIFIC INTELLIGENCE. Chemistry and Physics—Loss of Energy due to Chemical- Union, Gorr, 520.— Preparation of Acetylene, MaAQuonnE: New Alcohol of the Fatty Series, Sunp- WIK, 521.—Identity of Caffeine and Theine, DuNsTAN and SHEPHEARD: Lehr- buch der allgemeinen Chemie, W. Ostwa.Lp, 522.—Simplification of Tesla’s Experiments; Loss of Electric Charges in diffuse light and in darkness, E. Branuy: Influence of the character of metallic points on alternating discharges of Electricity between them, Wurtz, 523.—Registration of Magnetic variations, ESCHENHAGEN: Discussion of the Precision of Measurements with examples taken mainly from Physics and Electrical Engineering, S. W. HoLMAN: Prac- tical Physics: An Introductory Handbook for the Physical Laboratory, W. F. Barrett and W. Brown, 524. Geology and Natural History—A new Geological Society, 524.—Zeitschrift fiir praktische Geologie, KRanHMANN: Annals of British Geology 1891, J. F. BLAKE: Materialien zur Mineralogie Russlands, N. von KoKScCHAROW: Reports of the Missouri Botanical Garden, 525.—H. EH. Savon, Obituary, 526.—Disco- liths in clay beds, A. M. EpwarDs, 526. Miscellaneous Scientific Intelligence—National Academy of Sciences: American Philosophical Society, 527.—Hydrostatics and Elementary Hydrokinetics, G-. M. Mincuix: Elementary Mechanics of Solids and Fluids, A. L. SenBy: Poole Brothers’ Celestial Planisphere and The Celestial Handbook: Practical Astron- omy, MicHtE and HARLow, 528. ee D. Walcott, U. S. Geol. Survey. “TANUARA, ieee - Established by BENJAMIN SILLIMAN in 1818. AMERICAN J OURNAL Oe SCIEN OF, | EDITORS» : JAMES D. anv EDWARD S. ae ASSOCIATE EDITORS : Prorrssors JOSIAH P. COOKE, GEORGE LI. GOODALE 0 AND JOHN TROWBRIDGE, or CampBrines. Prorsssons H. A. NEWTON anv A. E. VERRILL, OF New Haven, . | Mosh aeacon GEORGE F. BARKER, or PHILADELPHIA. 7 H I RD SER : ES. VOL. XLV._[WHOLE NUMBER, CXLV_ No. 265.—JANUARY, 1893. WITH PLATES I-Vv. NEW HAVEN, CONN.: J. D. & E. 8; DANA. Game | TUTTLE, MOREHOUSE & TAYLOR, PRINTERS, 371 STATE STREET Published monthly. Six dollars per year (none prepaid). $6. 40 to foreign sub- seribers of countries in the Postal Union. Remittances should be made either by money orders, es aes or bank checks. : A. E. FOOTE, 4116 Elm Avenue, Philadelphia, Pa., U. §. A. MINERALS. Boléite, fine crystals, 25c. to $5.00; Enanivene! fine crystals, 25¢. to $5.00; Svabite, Hiortdahlite, Langbanite, Brandtite, Friedelite, Reinite, Melanophlogite, Geikielite and nearly all “obtainable new species in stock at reasonable prices, Paisbergite, the beautiful crystallized variety of Rhodonite from a mine ex- hausted eight years.ago, at less than half the European prices. Enstatite, Kjerulfine, Millerite, Sulphur, Aragonite, Gypsum, Pyrite, Hematite, Siderite, Xanthoconite, Calcite Pseudomorph after Aragonite, Dioptase from Congo in fine crystals, and hundreds of other finely crystallized species just received. Collections, from $1.00 per hundred specimens, upwards. Hard wood boxes for the same from $1.00 per 100 divisions upward. Meteoric Iron, Canon Diablo. Complete pieces from the same fall in which diamonds were discovered (this Journal, Nov., 1891), from 25c. upward. Lists of many meteorites on application. Catalogue of Minerals, 128 pages, free to customers and to those requesting it on headed paper, to others, 5c.; heavy paper, 10c.; bound, 25c. SCIENTIFIC BOOKS.—Catalogues of the largest stock of Scientifie and Medical books in the world sent on application. Please mention the subject in which you are’ interested. The following are a few rare and valuable works: Audubon, Birds and Quadrupeds of America, 11 vols., colored plates, fine ihalterushed devant Mor. ol SGile viene year e, 5S ae Sy ee peo ene $200.00 Gould, Mollusea of Wilkes’ Expedition, 4to text and folio Atlas, 52 col. DIGLES tase eee cee he een ec ee ea ea ee ee eae 65.00: Owen, Odontography. Comparative Anatomy of the Teeth, 2 vols., 168 Mlales= sees Re eek ae Se ee ae Sve ee Ro ek Ska ae ee me 15.00 Smithsonian Contributions to Knowledge, Vols. 2 to 21, 4to, published at AB DES O10 Ortaca ER eee aa Ss IR a Pos ae PA RT Sa aes an ee 125.00: Smithsonian Miscellaneous Collections, Vols. 1 to 31, 8vo_-------------- 75.00 (ophold: iniOz0a SiS 69 ats BN ce SS RA SES ec aS ave ee 5.00 Johnstonus, Historia Naturalis, 2 vols., 250 plates, folio, 1657 ____..___.- 5.00 Owen, Anatomy of Vertebrates, 3 vols. Riayat a a eee beh aegis tr 2 10.00. 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ESN Se fees Kuechenmeister, Parasites, and Siebold, Worms, 2 vols.,-_----__-------- Cooke, Handbook of British Fungi, 2 vols..___._.. 22._222-2--2---2-2-- Agassiz, Three Cruises of the Steamer Blake, 2 vols.....____------- ti A Intellectual Observer, 12 vols., many valuable papers and plates on Micro- Seopy; Zoolory, ete. ss soc 252 | eee SR eae eee Harris, Aurelian or Natural History of British Butterflies, 44 fine colored Plates; folio, mor 17886 ee ee eet ae b2 Wiel, THE AMERICAN JOURNAL OF SCIENCE [THIRD SERIES.] Oe Art. I.—The Age of the Earth; by CLARENCE Kine. With Plates I and II. AMONG the various attempts to estimate geological time none has offered a more attractive field for further develop- ment than Lord Kelvin’s mode of limiting the earth’s age from considerations of its probable rate of refrigeration, published in 1862.* At that time the consequences of his physical reasoning could not be fully applied to the condi- tions within the earth, so as to test the probability of his hypothetical case, for want of positive knowledge of certain properties of rocks, particularly the volume changes of melted rock in approaching and experiencing congelation, and the qualitative and quantitative effects of pressure upon the fusion and freezing points. Data then lacking are for the first time available, and with them it is proposed to apply a new crite- rion to the gradient of Lord Kelvin and to compare with it other cases of more probable earth-temperature distribution, which should have the effect of advancing his method of determining the earth’s age to a further order of importance. Accepting the hitherto unshaken results of Kelvin and G. H. Darwin, as to the tidal effective rigidity of the earth, and the further argument for rigidity advanced by Prof. S. New- combt+ from the data of the lately ascertained periodic variation of terrestrial latitude, as together warranting a firm belief in the rigid earth, it follows that solidity may be used as a criterion * Treatise on Natural Philosophy, Thomson and Tait, Part 2, Appendix D, + Monthly Notices of the Royal Astronomical Society, vol. lii, No. 5, 1892. AM. Jour. Sc1.—Tuirp Serius, VoL. XLV, No. 265.—January, 1893. 1 2 Clarence King—Age of the Earth. to test the probable truth of many cases of earth-temper- ature distribution; at least so far as to justify the rejec- tion of such as involve considerable liquidity of the upper couches. In an earth of which the superficial quarter of radius is composed of materials that contract from the fluid condition toward and in the act of congelation, any tempera- ture gradient in which the downward heat augmentation exceeds the rate by which advancing pressure raises the fusion point, would obviously reach a fused couche, and all such dis- tributions may be rejected as violating the requirements of rigidity. A recent investigation of the rock diabase in its relations to heat and pressure offers the formerly lacking means of testing the admissibility of many cases of earth-temperature distribu- tion from the point of view of solidity. Ten years ago ina laboratory established by me in connection with the ‘United States Geological Survey, Dr. Carl Barus began a series of experimental researches tending toward the solution of some of the unknown but important points of geological physics. It has been my privilege to indicate the direction of much of the inquiry. The understanding between us maintained his entire independence in the mode and prosecution of the inves- tigations and secured for him the fullest responsibility and credit for the purely physical results, many of which have at intervals appeared in this and other journals. For myself was reserved the privilege of making geological applications of the laboratory results. “One of the most important of these is Dr. Barus’s lately completed determination of the latent heat of fusion, specific heats melted and solid, and volume expansion between the solid and melted state, of the rock diabase.* To him [I am also very generally indebted for aid in considering the present problem. Diabase was chosen by me as fairly illustrative of the prob- able density and composition of the surface :03 or ‘04 of the earth’s radius. For Laplace’s law of distribution, density at the surface is taken at 2°75 and down one-tenth of radius at 3°88, yielding a mean density of the whole tenth of 3:33 and for the upper five-hundredths of about 3. For the whole tenth a rock like the extremely heavy basalt of Barensteint (sp. gr. 8°85) would approach closely a fair mean expression of density. Typical hornblende-andesite comes closest to the average density at the surface, but diabase (sp. gr. 2°8 to 3°), nearly enough fills the conditions of the shell which this study seeks to investigate. The particular diabase under examination came from Jersey City, and was taken from the immediate vicinity of the Pennsylvania R. R eut. * This Journal, Dec., 1891, and Jan., 1892. + J. Roth, Gesteins-Analysen, 1861, p. 46. Clarence King—Age of the Earth. 3 The following analysis is by G. W. Hawes :* ROVE WOS SR IaIS on, le Ne oe Rl ASTI es, oN Ma. AON Ua 3 YS CANS aa NT as eee eee eee Ss wey NOME ROI rsa ain) ee [st A THLeTROUSUO XC Gwe hee 2 Re serie gc ela 9°10 eT CWO XG Cle ee a nese) oe Crean aye Bee 1°08 MEMO aANOU STO XI ewes oe sins eee as See 0°43 NBII elke eater ee ey te enn emo nC re 9°47 Mintorme sian merce mites cure SN Oe Mm nee ea Se toe 8°58 RSV OXG ates ica Ieee UC A OT ea eae ce Bole Die A 2°30 ROU AS Awe eee SR ed ais Ae eee Bb 1:03 DnGTOMe eee OLS ale Sereda eee EE e/a 10500 99°76 Astronomical and geodetic requirements make necessary that density should proceed downward in shells of successively greater value, but the surface density is 2°75 and the mean density of the whole earth is not twice that of diabase, whence it appears that no probable chemical distribution of material could result in a surface couche of ‘05 of radius having a greater specific gravity than 3° to 3°3. Waltershausent in his interesting scheme of chemical distri- bution attempts to account for the augmentation of density chiefly by the increase of the heavy bases, but leaves the whole surface tenth of radius in silicates. Eruptions of alka- line earths or metals are unknown, in fact, with the exception of carbonates of superficial origin the whole visible body of the crust is of silicates, and the earliest rocks are seen to be made of the debris of stiJl older ones. All that can be said is that there is absolutely no known reason why the surface tenth of radius may not be of silicates, nor why specific material of widely different thermal properties from diabase should be postulated. The two principal conditions within the interior of the earth upon which physical state and all purely physical reactions of the specific materials depend, are the distributions from center to surface of pressure and heat. Secular or sudden variations of either or both have the power, if carried sufficiently far, to disturb chemical and physical equilibrium and produce changes of volume, rigidity, viscosity, and conductivity, as well as changes of state from liquidity to solidity, and the reverse. Before proceeding to consider in detail some of the results of heat and pressure as existing in the surface 05 of radius, it is desir- able to glance at the relations of these two great antagonistic * This Journal, III, vol. ix. + ‘Rocks of Sicily and Iceland.” 4 Clarence King—Age of the Earth. energies in the whole radius. Plate I gives earth-pressures from Laplace’s law expressed in a gradient of which the ordi- nates are 100,000 atm. (iarger divisions 1,000,000 atm.) and the abscissee tenths of radius. Upon the same diagram are delin- eated two hypothetical cases of earth-temperature, the abscissze remaining as for the pressure line, tenths of radius, and the ordinates corresponding in interval to the 100,000 atm. lines, are taken as each 1,000° C. The left vertical boundary of the plate represents the center of the earth and the right one the surface. The upper heat gradient corresponding to a tem- perature of 3,900° C. at the earth’s center is the 100x10° eurve of Kelvin. The lower is computed for a central tem- perature of 1,741° C., about the melting point of platinum, and a secular cooling in 20x10° years. Data for the construc- tion of these gradients are given in the tables a few paragraphs later. The feature here called attention to is the exceedingly slight change of temperature from very near the surface down- ward to the center. In the Kelvin gradient even after the lapse of 100x10° years the original maximum temperature is reached within ‘05 of radius and remains thence unchanged to the center. Pressure, on the other hand, augments with one downward sweep through the entire radius. On Plate I its line is seen cutting both temperature gradients near the surface, passing the 1,741° C. line at a pressure of 175,000 atm., and the Kelvin line at 390,000 atm.; thence steadily augment- ing until at the center it reaches the impressive figure of 3,018,000 atmospheres. Since we are to look to heat and pressure for the keys to the physical condition of the matter of the earth, it is important to realize from the relation of these gradients, first, that the great effect of heat in opposing and overcoming the results of pressure must be limited to superficial earth-depths not exceed- ing 200 miles for an earth of the Kelvin assumptions; second- ly, that below this depth and onward to the center there is a complete reversal of relations and a great and continual increase of pressure available to oppose and destroy the vol- umetric and other molecular effects of a temperature which has ceased to increase. The empire of heat over pressure is thus seen to be purely superficial, while that of pressure over heat begins not far below the surface and extends more and more powerfully to the center. This is obviously true only for such moderate assumptions of heat and time as are given in the gradients on Plate I, but it will be shown later that these figures are, upon the criterion of solidity, far more proba- ble than very hot or very old earths. Out of the infinite number of possible earth-temperature gradients, to discriminate the probably true case, is of critical Clarence King—Age of the Earth. 5 importance in any attempt to determine the earth’s thermal age or to delimit the period of active geological dynamics. Pressure and Temperature Tables. The following tables offer figures for the construction of the pressure and some of the temperature gradients on both Plates Tand Il. Data for the distribution of earth-pressure may be obtained either from the formula of Laplace or that of G. H. Darwin for radial earth density, combined with the known decrease of terrestrial gravitation from center to surface. In table 1, Laplace’s law is used as giving the most conserva- tive values of density at great depths. For the superficial -2 of radius, however, the two. . density laws are near together, and as the thermal. phenomena which determine the earth’s age are probably wholly in the surface tenth, either law might be applicable to the present purpose. As, “however, Darwin’s law requires a surface density of 3°7, while Laplace only 2°75, the latter accords better with the average specific gravity of superticial rocks and is, therefore, here preferred. Tables 2, 3 and 4 give data for three temperature gradients derived by mechanical quadrature from the well known Fourier equation in the manner given by Lord Kelvin, and are con- sidered as sufficient in number and variety to indicate the character of the data; figures for the other gradients shown on Plate IL are therefore omitted. Table 2 presents data for the Kelvin gradient, 3,900° C. initial excess, surface rate ‘03600 in degrees Centigrade per meter of depth, and secular cooling 100x10° years. © Earth temperatures in ° ©. are given for depths that are expressed both in miles and fractions of radius and extend to 250 miles or about ‘06 of radius. Surface rate appears both in ° Fahr. and feet, and °C. and meters. Tables 3 and 4 exhibit similar data for earths of lower initial excess and shorter periods of secular cooling. ‘Table 3 is computed for an earth of 1,740° C., 20x10° secular cooling, and table 4 for 1,230° C., 10x10° cool- ing. TABLE No. 1. Estimated Earth Pressures (Laplace’s densities) n being radial distances from the center of the earth and p being the pressure corresponding to m expressed in atmospheres. Earth Rad. Atm, Earth Rad. Atm. Earth Rad. Atm. 1-000 0) "94 116000 5 1680000 "995 8600 "92 162000 “4 2100000 "990 17400 “90 199000 3 2470000 "985 26400 °80 497000 °2, 2770000 “980 35600 o7K(0) 852000 1 2950000 °960 74500 *60 1260000 0 3020000 6 Clarence King— > ] Bulliopsis integra, Nassa peralta, Murex acuticostata, Scala ex- P gra, ’ ’ pansa, Turritella variabilis. 2. The Jones’ wharf fauna ; characterized by such species as: Mytiloconcha incurva, Arca elevata, Carditamera producta, Astarte obruta, Crassatella turgidula, Mysia acclinis, Cytherea marylandica, Mya producta, Panopzea americana, Turritella tere- briformis, Calliostoma Wagneri. 3. The Plum Point fauna, characterized by such species as: Pecten Humphreysi, Arca subrostrata, Byssoarca marylandica, Pectunculus parilis, Astarte varians, Astarte exaltata, Crassatella melina, Lucina Foremani, Cardium leptopleura, Corbula elevata, Isocardia Markoei, Venus staminea, Venus latilirata, Pleurotoma marylandica, Pleurotoma bellacrenata, Scala pachypleura, Turri- tella indenta, Turritella exaltata, Solarium trilineatum. In concluding, it may be of interest to make a few brief comparisons between these observations and those of earlier writers. G. D. Hurris—Tertiary Geology of Maryland. 31 Conrad,* in 1841, seemed not to detect the true stratigraphy of the fossiliferous deposits he noted along this shore, and strangely enough, apparently believed them to extend nearly horizontally from Fair Haven to Drum point. In 1880, Heilprin} concluded from a study of the paleonto- logic literature on the subject, that there must be a southern dip along this shore in so much as two faunas, differing con- siderably in their relative proportions of recent and extinct species, are here represented. To the older fauna, the species occurring at Fair Haven, “Col. Blake's,’ “Capt. Hance’s,” and those from the base of the “Cliff near Beckett’s,” are referred; to the newer, those from the upper part of the last mentioned cliff as well as those from localities south of Cove point. Had Heilprin examined these sections personally, his conclusions would doubtless have been quite different. The three-foot fossiliferous layer in the upper part of Conrad’s section at “‘ Beckett’s”’ is obviously the same as Zone d of the present essay, and not the Jones’s wharf beds as Heilprin sup- posed. Nor is it this bed that furnishes the St. Mary’s fauna below Cove point: between the two occur at least 70 feet of deposits bearing a well marked fauna. In Darton’st paper on the “ Mesozoic and Cenozoic Forma- tions of EKastern Virginia and Maryland,” published in 1891, he subdivides the “ Chesapeake formation ” into three parts, thus: “The lower beds consist mainly of dark-colored clays and fiae, mealy sand containing the extensive anv well-known ~ diatomaceous deposits. These are succeeded by lighter colored clays and sands, with occasional local inclusions of blue marl. The upper beds are coarse-grained, and consist chiefly of white beach sands containing shells and deposits of shell fragments, and occasional argillaceous members.” The outcrops at Her- ring bay are said to belong to the lower beds; those on the lower St. Mary’s river to the medial; and “those along the lower Patuxent river and the adjoining shores of Chesapeake bay,” to the upper beds. *2d Bull. Proc. Nat. Inst., 1842, p. 176. + Proceed. Phila. Acad. Nat. Sc., 1880, pp. 23-30. ¢ Bull. Geol. Soc. Am., vol. ii, p. 444. 382 F. A. Genth—“ Anglesite” associated with Boléite. Art. Ill.—On the “ Anglesite,’ associated with Boléite, INO. 4555) by shy ALG ENirEe MALLARD and Cumenge state in their interesting investiga- tion on boléite* that anglesite, generally covered with a coat- ing of gypsum, of variable thickness, is associated with the boléite from Boléo, Lower California, Mexico. These crystals showed such a peculiar appearance that I thought they de- served a fuller investigation, for which Mr. Clarence 8S. Bement with his usual liberality, furnished me with excellent material. The crystals, from 2 to 20™™ in size are often distorted, but show generally a very common form of anglesite, the planes e, mand J predominating. They are opaque, and of a luster, between vitreous and greasy, their color is from white to bluish white, some show minute blue spots from a slight contamina- tion with boléite. Many crystals havea coating of gypsum or minute scales of the latter implanted, while others are entirely free from it. Sp. gr. = 4401. The material for the analysis was selected with great care and the purest that could be obtained, it gave: Molecular ratio. IPDSO tesa ouetecee OMG “IE |» CaSOi es Mena A780 Orlane TO Caen. MESS misih 1! @ Boléite by diff, .... 2°00 100-00 This gives the formula :2PbSO,+CaSO,+2H,0. Asit is not very likely that 2 mol. of PbSO, should have crystallized with one mol. of gypsum in exactly the same form as anglesite, we: must come to the conclusion, that the so-called anglesite erys- tals from Boléo are pseudomorphs after a mineral of the com- position: 2PbSO,.CaSO,, which has not yet been observed in its original condition, but only after the calcium sulphate in it had taken up two molecules of water and changed into gyp- sum which now forms a mechanical mixture with the remain- ing anglesite, from which it can be completely extracted by water. The fine powder of two small crystals was treated with water, as long as any precipitate of calcium oxalate could be formed in the filtrate ; a small quantity of lead in the solution was removed by hydrogen sulphide. * Bull. Soc. France. de Mineralogie, December, 1891. R.S. Woodward—Iced Bar Base Apparatus. 33 The analysis gave : eS OF ere eters te tak gue aC 74°76 aS Orne bee cee a id Sheer a 19°64 H,O required to form gypsum__ 4°20 99°60 showing that these crystals had a considerable admixture of gypsum. Chem. Laboratory, 111 8. 10th St., Philadelphia, Nov. 22d, 1892. Art. 1V.—Preliminary Account of the Iced Bar Base Apparatus of the U. S. Coast and Geodetic Survey ;* by R. 8. Woopwarp. Listorical Note.—The use of ice in thermometry to furnish a standard temperature naturally suggests the availability of ice to fix the temperature of a standard of Jength when used in laboratory comparisons or in measuring base lines — It does not appear, however, that ice has been generally used even in laboratory work with standards of length,t and I am not aware that any attempt has been made hitherto to measure a base with a bar whose temperature is controlled by means of melt- ing ice. The feasibility of using such an apparatus in base measurement has, nevertheless, been suggested and maintained by several persons. One of the first, if not the first, to out- line a scheme for such an apparatus is, I believe, Mr. E. S. Wheeler, a former colleague on the U. 8. Lake Survey. Mr. Wheeler's plan is advocated by Professor T. W. Wright in his treatise on the Adjustment of Observations.t The ‘late Cap- tain C. O. Boutelle of the U. S. Coast and Geodetic Survey also advocated the use of such apparatus. Soon after joming the U. 8. Coast and Geodetic Survey in July, 1890, 1 was requested by Dr. Mendenhall, Superin- tendent, to devise means of testing in the most thorough way * Communicated by permission of the Superintendent of the Survey. The sub- stance of this paper was presented before Section A of the American Association for Advancement of Science, at the Rochester meeting, August, 1892. + From published accounts it would appear that the most extensive series of laboratory comparisons of standards, wherein ice was used, are those of the U. 8. Lake Survey, conducted under the superintendence of General C. B Comstock, Corps Engineers, U.S. A. In these comparisons ice was successfully used dur- ing several years. See Professional Papers Corps Engineers, U.S. A, No. 24. ¢D. Van Nostrand, New York, 1884. See also this Journal, III, vol. xxviii, p. 479. AM. JOUR. 5O1.—THIRD SERIES, VOL. XLV, No. 265.— JANUARY. 1593, 3 34 R.S. Woodward—Iced Bar Base Apparatus. practicable the efficiency of the various forms of base appara- tus used by the Survey and especially the efficiency of long steel tapes or wires. Accordingly, considerable study was given to this subject during the antumn of 1890 and the winter of 1890-1, and the plans and specifications for the iced bar apparatus considered in this paper were matured and approved early in the spring of 1891. It was constructed in Washington, partly by the machinists E. N. Gray and Co., and D. Ballauf, and partly by the Instrument Division of the Survey. Before proceeding to a description of the apparatus I desire to acknowledge my indebtedness to colleagues of the Survey for valuable suggestions and criticism. I am specially in- debted to Mr. John S. Siebert, who verified all of the pre- liminary calculations relative to tie stability and efficiency of the apparatus, and who elaborated many of the designs and made most of the working drawings for its construction. I am particularly indebted also to Mr. E. G. Fischer, chief mechanician of the Survey, whose knowledge of and skill in mechanical appliances were frequently appealed to. Finally it affords me pleasure to state that my friend Mr. E. 8S. Wheeler, who has had extensive experience with base appara- tus, happened to visit Washington about the time the plans for this apparatus were completed and gave me the benefit of his advice and criticism. DESCRIPTION OF APPARATUS. The measuring bar.—The measuring bar of this apparatus is a rectangular bar of tire steel. It was rolled in the steel works at Lancaster, Pa. It is 5-02™ long, 8™™ thick and 32™™ deep. A cross-section is shown at A in the accompanying drawing. The upper half of the bar is cut away for about 2% at either end to receive the graduation plugs of platinum-iridium, which are inserted so that their upper surfaces le in the neu- tral surface of the bar. Three lines are ruled on each of these plugs, two in the direction of and one transverse to the length of the bar. These lines were ruled by Mr. Louis A. Fischer, Adjuster in the Weights and Measures Office. The longitudi- nal lines, which serve to limit the parts of the transverse lines used, are 0°2™™ apart. T’o secure alignment of the bar eleven German silver plugs of 5™™ diameter are inserted at intervals of 495™™ along the bar so that they project about 1™™ above its top surface. The upper surfaces of these plugs are all the same distance, within a few hundredths of a millimeter, from the neutral surface of RL. S. Woodward—Iced Bar Base Apparatus. 35 the bar On the top of each plug is ruled a fine line in the direction of the bar as shown at P in the drawing. The length of the bar as regards alignment is defined to be the distance between the transverse graduation marks when the upper surfaces of the alignment plugs are all in one plane and CROSS SECTION. ea TN eS OW Girt LLU Ly Scale — % ROOD WLLL: UZ LP END OF BAR. ill, a Seo teeters eee A S) 36 R. S. Woodward—Iced Bar Base Apparatus. when the lines on these plugs are in one straight line. The means of securing these two adjustments are described below.* The ¥-Trough.—The most important and distinetive part of this apparatus is the trough which supports the bar, keeps it aligned, and carries the ice load essential to control the bar’s temperature. This trough is called the Y-trough by reason of the resemblance of its cross-section to the letter Y. The drawing shows a cross-section of this trough. It is made of two steel plates 5:14" long 25-5°" wide and 3™™ thick. They are bent to the angle BCD of the figure and are riveted together as shown at E, thus making the angle of the trough BC F=60°. The bar, shown in cross-section at A, is sup- ported at every half meter of its length by saddles, one of which is shown in the figure. These saddles are rigidly at- tached to the sides of the trough by screws at S,S. . Each saddle carries one vertical and two lateral adjusting SCreWS as shown at V, L, L’.. These screws serve to fix the alignment of the bar. The lateral adjusting screws of the saddles at the ends of the bar are of the same height, which is equal to that of the lower screw L’ of the diagram. The lateral adjusting screws of the intermediate saddles on either side of the bar are alternately high and low. The object of this disposition is two-fold, to wit: Ist, to prevent pinching the bar, which might more readily occur if the lateral screws were all oppo- site to one another; 2d, to afford means of rotating the bar slightly about its longitudinal axis, so that for a fixed and nearly vertical position of the trough the graduated surfaces of the bar may be made horizontal. The vertical adjusting screws of the saddles project, as shown in the diagram, below the vertex of the trough, and their capstan heads are accessi- ble through slots cut in the web of the trough. These slots serve also as drainage-ways for the melted ice. To prevent circulation of air through them they are stuffed with cotton batting, through which the water percolates freely. The ends of the trough ¢ are closed with wooden V-shaped blocks. The trough is very rigid in all directions and especially so with respect to vertical stresses. It weighs 82 kilograms exclusive of the bar and ice load. The whole trough is coy- ered by a closely fitting jacket of heavy white cotton felt, which protects the trough and ice load alike from direct radiation. * The form of bar described is evidently not the best form. Theory and experi- ence indicate that a bar having a Y-shaped cross section with metric subdivisions on its neutral surface would best meet the requirements. However, the question which presented itself in planning the apparatus was not what is the best form of bar, but what is the most economical form possessing the requisite properties. I. S. Woodward—lIced Bar Base Apparatus. 37 For measuring grade angles a sector reading by two oppo- site verniers to 10'’ is attached to one side of the trough near its middle point. Thus arranged this sector has great sta- bility. Mi, he ice load and «ce crusher.—W hen the apparatus is in use the Y-trough is completely filled with pulverized ice, the upper Panece of which is rounded to about the height shown by the curve B HF in the diagram. The amount of ice required for this purpose is about 40 kilograms, or 8 kilo- grams per meter of the bar’s length. The ice, by reason of its weight and the sloping sides of the trough, is kept in close contact with the bar. This is especially the case when the apparatus is in use, for it is then trundled along on its cars with sufficient jarring to overcome any tendency of the ice to pack. For covering the ends of the bara small quantity of ice is cut with a jack plane. Ice thus cut, like wet snow, packs well and permits making a small conical hole through it to ae graduation plugs. A very essential auxiliary to the use of the apparatus is an ice crusher to pulverize the ice. The machine used is a modi- fication of the Oreasey ice breaker manufactured at Phila- delphia, Pa. It is a small light hand machine which, as modified, does its work very satisfactorily. With it 40 kilo- grams of ice may be pulverized in ten minutes or less. The particles of crushed ice vary in size from the smallest visible up to the bulk of a cubic centimeter; and this gradation in size appears to be advantageous as compared with uniformly finer particles like those of snow, since there is less liability of regelation and packing. The cars and portable track.—The Y-trough is mounted on two ears, the saddles or bolsters of which are attached to the trough 40™ from either end. Each saddle is attached rigidly to the trough above and to a jack serew below. The jack screw is attached to a slide rest which is connected rigidly with the base of the car. The slide rests are provided with screws to give slow motions in the direction of the trough’s length and transverse to its length. The jack screw cylinders have right and left handed threads at their respective ends and are turned by a short capstan bar. They give thus the rapid vertical motion to the trough essen- tial in bringing the bar quickly to focus under the micro- scopes which define its position. The cars have each three wheels and run on a_ portable peek whose width is 30™. Three sections of this track, each ™ long, are provided; and each section is carried forward as the cars are rolled along during the measurement of a line. It thus appears that instead of lifting up and carrying forward 38 R.S. Woodward—Iced Bar Base Apparatus. the measuring bar as with most forms of apparatus, this rather delicate and diflicult operation is supplanted by that of moy- ing the portable tracks. ‘The micrometer microscopes.—To define the successive posi- tions of the bar in measuring a line, micrometer-microscopes are used. Through the courtesy of General Casey, Chief of Engineers, U. 8. A., the Survey was enabled to borrow the four microscopes and the cut-off cylinder of the Repsold base apparatus* used on the U.S. Lake Survey. These are espe- clally well adapted for use with any line measure apparatus. As designed by the Repsolds and as used on the Lake Survey the microscopes were mounted on iron tripods. These latter having been destroyed by fire while stored at the Engineer depot at Willett’s Point, N. Y., it was essential to replace them by some equivalent device. In view of the economic and other features of the special work contemplated with the iced bar apparatus it was decided to mount the microscopes on wooden posts set firmly in the ground. To connect the micro- scope with the post a cast-iron post cap is provided. It fits like a box cover on the end of the post and is clamped rigidly to it by means of a screw. The microscopes are provided with levels and leveling screws so that their axes may be made vertical. They are mounted on slide rests which give a motion of 2™ in the direction of the line measured or transverse to it. To secure additional displacement in the direction of the line a small rotary motion is provided for in the connection of the micro- scope with the post cap. The micrometer heads of the micro- scopes are divided to read microns directly, one revolution of the screws corresponding to 0-1™. When used in the field the microscopes are shaded from the sun by large umbrellas. With this method of mounting the microscopes it is advan- tageous if not essential to set the microscope posts and those supporting the portable track before beginning measurement. End marks and method of reference thereto.—The method of marking the end of a line is essentially that of the Repsolds and fully described in the Lake Survey Report referred to above. It consists in the use of a metallic bolt terminating in a spherical head, the bolt being em- bedded in a stone or other stable mass set in the ground. The center of the bolt head is the fiducial point. To refer to this point a cylinder called a cut-off cylinder is used. It terminates at one end with a conical hole which fits over the spherical head. The other end is provided with a transverse level and graduated scale. The scale is * Fully described in General Comstock’s report referred to on page 33. RL. S. Woodward—Iced Bar Base Apparatus. 39 brought by a rack and pinion motion to focus under the micro- scope whose position relative to the fiducial point is sought. The seale and level, which are parallel to each other, are placed parallel to the line measured. With the cylinder thus disposed readings of the micrometer on the scale and of the position of the level bubble are made. The cylinder is then turned 180° in azimuth and the scale and level readings are again observed. From these observations and the height of the scale above the bolt head, the horizontal distance (in the direction of the line) between the mnicrometer zero and the fiducial point may be accurately determined. Adjustments of apparatus.—The most important adjust- ment of the apparatus is the alignment of the bar in the Y-trough. This adjustment is made when the ice load is in the trough and after the latter has had time to assume a stable shape. This time does not exceed 15 minutes. As already stated, the alignment of the bar requires that the upper surfaces of the alignment plugs be in one plane and that the limes on these plugs be in the same straight line. The former requisite is secured by a striding level whose feet are 99 apart, so that they reach from any plug to the second adjacent plug. Beginning at one end of the bar the plugs are numbered 1, 2, 8,—11. By placing the level feet in succes- sion on plugs 1 and 3, 3 and 5, ete. plugs 1, 3, 5,—11 are brought into the same plane by means of the corresponding vertical adjusting screws, the screws under plugs 2, 4,—10 being loosened if need be to secure this end. Having thus adjusted plugs 1, 3, 5,11, the level is placed on plugs 2 and 4, 4 and 6, etc., and the vertical screws are brought up to contact with the bar but mot raised enough to disturb the previous adjustment of 1, 3, 5—11, which are the principal detining plugs in this al ' To place the lines on the plugs in the same straight line a sharp pointed plumb bob suspended from a fine brass wire stretched over the trough was originally used. This device with the aid of the lateral adjusting screws of the saddles per- mits placing the lines in proper position within 0-1™™ when the trough is fully loaded with ice. Experience with the appa- ratus, however, showed that the simpler method of stretching the wire, or better still, a fine thread, close over the plugs when the trough is about four-fifths loaded secures equally good results. It was feared before using the apparatus that the daily tem- perature range might produce an appreciable effect on the length of the bar through change in curvature of the trough. Hence the accurate method of measuring such change by the striding level was provided. But experience shows that the 40 Lt. S. Woodward—Iced Bar Base Apparatus. change in shape of the trough gives rise to quite insignificant changes in length of the bar. Indeed, the aligninent of the bar may be maintained so perfectly that the correction for its curvature will not exceed a few tenths of a micron. The grade sector of the apparatus is adjusted to zero when the graduated surfaces of the bar are in the same horizontal plane. To secure the latter condition an engineer’s level is used; and with appropriate care the difference in height of the ends of the bar can be made zero with a probable error not exceeding +071". The microscopes are provided with fixed levels, which, when once adjusted, enable the operator to make the axes of the microscopes vertical. They are also provided with clamp screws so that they may be rigidly held in proper position. When posts are used to support the microscopes, as has been the case with this apparatus thus far, they must be set in their proper positions within a centimeter or two. It is easy and convenient, however, to adjust their sides facing the line to be measured with much greater precision. When firmly set, a line parallel to the base may be deliberately ranged out with a theodolite of high magnifying power, and this line may be defined by suitable marks on each post. Then by simply noting the distance of the axis of the bar during measurement from this reference line an accurate correction for deviation of the bar from parallelism with the base may be obtained. This adjustment of the posts though not essen- tial to the use of the apparatus has been followed. Another convenient adjustment which the use of posts per- mits is that of making the tops of several or many posts con- form to one grade. By this means, since the four microscopes used are closely alike, the grade angles for several or many bar lengths are nearly the same—a condition favorable to pre- cision in determining grade corrections. As an additional precaution in the use of this apparatus the relative heights of the alternate post tops have been determined with an engt- neer’s level. Method of measurement.--To conduct the measurement of a line with this apparatus eight men are required, to wit: three observers; one recorder; one man to move the micro- scopes ; and three men to move the car tracks, the microscope shades, and the ice and ice crusher. The operation of measurement proceeds as follows: The position of the microscope relatively to the fiducial point at the end ef the line having been observed as explained above, the rear end of the bar is * brought to focus under that micro- scope by the rear end observer. By means of a lever which erips into the track and hinges on the car, the latter observer R.S. Woodward—Iced Bar Base Apparatus. 4] holds the bar near to bisection under the microscope while the front end observer brings his microscope into position over the front end of the bar; to do which he can make use of the lateral motion of the trough, of the microscope, or both. When the bar is adjusted at both ends the rear observer brings the rear end graduation accurately to bisection between the micrometer wires by use of his lever without turning the micrometer screw. Simultaneously he gives the signal ‘‘ read ” to the front observer, who brings his micrometer wires to bisect the front end graduation mark by moving the micro- scope, the micrometer wires, or both. The observers then read their micrometers and the recorder notes them down in his book, after which the rear observer turns his micrometer screw a half revolution or less backwards. The observers then exchange positions. The rear observer carrying with him his lever applies it to the front car and brings the front end graduation to bisection without disturbing the micrometer threads from their previous position; while at the signal “read” the front observer bisects the rear end graduation by moving the threads with the micrometer screw. They then announce the readings as before and the recorder jots them down, notifying the observers at the time if the serew revolu- tions differ from their previous values. This process eliminates the relative personal equation of the observers, and checks any blunders of whole revolutions in reading the microscopes, each of them being read four times, and the four readings being the same within » few microns. The probable error of a bisec- tion is less than +1”. While the bar is in position under the microscopes, the third observer measures the distance of the front end (and the rear end at starting) of the axis of the bar from the reference line, and adjusts the sector level bubble to center, taking care at the same time to keep away from the microscope posts when the bar is observed. The grade sector reading is then made and recorded, and the bar is rolled rapidly forward to a new position. As soon as the rear end of the bar is brought safely to posi- tion under a microscope the one previously at the rear end is taken up and carried forward by the microscope porter who clamps and adjusts it on a new post. Likewise, as soon as a section of track is passed over it is carried forward to a new position. The observers stand on platforms which rest at their ends on the ground at a distance of about one meter on either side of a microscope post. At intervals of 20 to 40 minutes fresh ice is supplied, the trough being run to the rear of or ahead of the two micro- 42 LR. S. Woodward—Iced Bar Base Apparatus. scopes which were last used. The trough is completely un- covered in this operation and the ice stirred up and supple- mented by the amount requisite to replace the waste. This amount is usually 3 to 5 kilograms. The speed of measurement has varied somewhat with cir- eumstanees. It has usually been about 100" per hour. 750™ were measured in 7 hours on two different dates; and a kilo- meter would not be an excessive day’s work. Tue EFFICIENCY OF THE APPARATUS. Plan of operations with apparatus in 1891.—The plan sub- mitted by me to the Superintendent of the Survey for the use of this apparatus on the Holton Base, of the transcontinental triangulation in Indiana, contained the following recommenda- tions which were approved and carried out during the summer of 1891: (a) To construct a 100-meter comparator near the Holton Base; to standardize this comparator by repeated measurements with the iced bar; and to use this comparator in turn to standardize and study the behavior of 100™ tapes or those of less length, or any other form of base apparatus. (6) To use the iced bar in addition to make several measures of a kilometer at least of the base line; so that the efficiency of the different forms of apparatus used in measuring the whole base could be tested on the actual ground over which they were applied. The plan also contemplated making a determination of the length of the steel bar of the apparatus in terms of one of the International Prototype Meters. This was done, but owing to the small amount of time available before going to the field it was impossible to reach anything better than a tentative value. Before giving the results of the measures made with the iced bar it is proper to give a brief description of the long comparator and of the kilometer whereon the apparatus was used. The 100-meter comparator.—The 100-meter comparator of the Holton Base was a line 100™ long fitted for measurement with the iced bar apparatus. Twenty-one beech wood micro- scope posts 1-8" long and 15°"xX15™ in cross section were set firmly in the ground 5™ apart on a level plat near the north end of the Base. Alongside of the posts a stationary railway track was laid, the support posts of which were half way be- tween the microscope posts. The ends of the line were marked by brass, spherical headed bolts cemented into the upper ends of stone posts, which latter were well set in beds of concrete. The comparator was covered by a shed 110™ long by 3" wide. Its length extended nearly east and west. It was covered at the ends and on the south side as well as R. 8. Woodward—Iced Bar Base Apparatus. 43 overhead, but the north side was left open in order to permit free access of daylight and air. This comparator was built by Assistant A. T. Mosman after plans drawn up by Mr. Siebert. It answered its purpose very satisfactorily. An efficient auxiliary applied by Assistant Mosman was a sawdust covering to the ground along the com- parator. This covering absorbed dust and moisture, and pre- vented the transmission of disturbances through the ground to the microscope posts. The stability of these posts may be inferred from the measures of the comparator interval given below. The standard kilometer.—A nearly level portion one kilo- meter in length of the Holton Base was selected by Assistant Mosman for measurement with the iced bar apparatus. The base line, whose entire length is 5°5 kilometers, runs in a nearly north and south direction across the Crawfish Flats of southern Indiana. The portion selected for the iced bar measures passes for 600" of its length through a dense forest growth, leaving about 200™ at either end in open fields. The whole kilometer is on low ground and the part within the forest is, in a wet season, subject to partial inundation. The soil along the kilometer is a stiff clay which is very firm when dry but which assumes a jelly-like mobility and elasticity when saturated with water. The way through the forest was cleared and the end stones of the kilometer were set under the direction of Assistant Mosman during May and June, 1691. During the latter half of the following August and early September the microscope and track posts were set along the line. Owing to frequent and heavy rains this was a tedious operation. Many of the posts were set in the water which filled the post holes as fast as they were dug. It is impossible, therefore, to present any statistics as to the speed with which this work can be done under usually favorable circumstances. It may be remarked, however, that it is a work which requires but little skilled labor. In addition, it should be said that the microscope posts were set with considerable precision. Accurate spacing of the posts to 5™ apart was secured by means of 100™ and shorter steel tapes; while the posts were aligned by means of a theodolite. The probable error in position of a post face with respect to the kilometer line does not, I think, exceed +3™™; while the probable error of the reference line fixed on the posts as explained above does not exceed +1™. The bolts marking the termini of the kilometer were cemented in the end stones by Assistant Mosman early in August, after their proper relative positions had been deter- mined by Assistant O. H. Tittmann with the Survey secondary 44 FR. S. Woodward—Iced Bar Base Apparatus. apparatus.* Intermediate stones dividing the kilometer into four nearly equal sections were set on September 7, 1891. Each of them consisted of a half cubic meter of conerete set in the ground so that its upper surface was about even with the ground surface. On the top of each stone was cemented one of the Repsold cut-off plates which are provided with spherical headed bolts for use with the cut-off cylinder previ- ously deseribed. When these intermediate stones were set, the ground along the line was so wet that it was a matter of difficulty to keep the water out of the excavations while the concrete was being rammed into place. These stones did not become dry and hard until deep trenches were dug about them on September 18, 1891. For this reason it is probable that these stones were much less stable during the first two measures of the kilometer (Sept. 10-15) than during the last two measures (Sept. 26-30). ftesults of measures of 100" comparator interval.—The earliest experience with the iced bar apparatus showed that the personal equation of the observers may cause appreciable constant error, and hence the method of interchange of the observers already explained was adopted. The first five measures of the comparator interval, however, were made without interchange of the observers. In place of such inter- change direct observations for relative personal equation were made on the bar. The greater part of the measures of the comparator interval were made by starting at the west end and moving the bar toward the east. Some of the later measures were made in the opposite direction and they disclose, apparently, a systematic error depending on the direction of measure. The same kind of systematic error is indicated also by the measures of the kilometer referred to below. In order to explain the data of the comparator measures clearly and fully let D =distance between spheres of comparator = 1007+39°5™™ approximately, B,,= length of 5™ steel bar No. 17 in ice, % = the relative ne equation of the two observers on the bar, Q = quantity measured on cut-off scale, v =the most probable correction to Q4 Then, for one position of the observers a measure of the comparator interval gives an observation equation of the form *This is an end measure apparatus consisting of two steel rods encased in wood, with mercurial thermometers to give their temperatures. +The quantity Q involves the error of measuring the lne as well as the errors in position of the first and last microscope with respect to the fiducial points. LR. S. Woodward—Iced Bar Base Apparatus. 45 D+ 20x — 20B,,—Q=2, while for the reverse position the equation is D—20x — 20B,,—Q=v. The following table gives the data furnished by the first group of measures of the comparator. These data include the observations fer personal equation, which give rise to observation equations involving the quantity # only. Although the latter equations should have somewhat greater weight than the others they are all treated as of equal weight in this purely preliminary statement. Data for length of 100” comparator. Date Direction of 1891. Measure. Observation Equations. mm mm July 30 W to K D + 20a —20B,,—39°532= +0°052 30 W to E D +20a—20B,,—39'574= + -010 30 W to E D+20x%—20B,,—39°660=— -076 30 rupees 2.020 = 0049s] 32 Os. 31 W to E D+20e2—20B,,—39°548= + -036 3 ae ls salkO) 82255) 02040 == 008 Aug. 3 W to E D+ 20H%—20B,,—39°643=— -059 3 Senne SEU? 9 See ORM = O19) 4 W to EK D+ 20%—20B,,—39°624=— -040 4 W tok D—20x2—20B,,—39'476=— :016 4 gatas +20%.-.. . — 0°022=+4 -040 Ti W to E D+20%—20B,,—39°528=+4 -056 7 W tok D—20x—20B,,—39:°424=+ 036 The resulting normal equations are: 9D + 1002= 9(20B,,+39™™)+ 5-009, 100+4600 = 100(20B,,+39™)-+66-610 ; whence D = 20B,,+39°522™"-+0-011™, eg =+3"/1+0"5, The probable error of an observed quantity of weight 1, or of a single measure of the comparator without interchange of observers to eliminate personal equation, is +30”. Later in the season (Sept. 24 to Oct. 6) a second set of meas- ures of the comparator interval was made. In each of these measures the observers interchanged positions, and on two dates the interval was measured in the direction east to west as well as in the direction west to east. The results of these measures are given in the following table which is arranged in the same form as the preceding table. 46 LR. S. Woodward —Iced Bar Base Apparatus. Data for length of 100" comparator. Date Direction of 1891. measure. Observation equations. mm mm Sept.24 WtoE D+20#—20B,,—39:272=+0:134 24 W to E D—20x%—20B,,—39'191=+ ‘149 Oct. 2 W to EK D+ 20x—20B,,—39°394=+ :012 2 W to E D—20x2—20B,,—39°320= + :020 2 EK to W D+20%—20B,,—39°432=— :026 2 E to W D—20x—20B,,—39°369=— -029 6 W to H D+202—20B,,—39-422=— -016 6 W to E D—20x2—20B,,—39°370=— -030 6 E to W D +20e—20B,,—39°512=— '106 6 E to W D—20x—20B,,—39:449=— :109 The normal equations from this group are: 10D-+ Oe = 10(20B,,+39)+3-731, 0 +4000 = 46 660; whence mm D = 20B,,+39 373-40-019, = 147410. The probable error of an observed quantity of weight 1, or the probable error of one measure without interchange of observers, is —61”. The values of D resulting as above from the two groups of determinations differ by 0:149™", a quantity which is about ten times the average of the probable errors of the separate values. It seems most probable, in view of our experience on the standard kilometer, that this difference is due to a movement of the end marking stones of the comparator. The residuals of the second group of measures indicate a progressive change of this sort. The data of Oct. 2 and 6 indicate that measures made in the direction west to east give smaller lengths than measures in the opposite direction. Thus the lengths for Oct. 2 are :— mm Direction W to E 20B,,+39°357, “ EtoW 20B,,+39-400, Their difference is 43” and the corresponding difference for Oct. 7 is 84“. They show an average difference of 64”, which is equivalent to an error of 1-6 per bar length relatively to the mean of a forward and backward measure of a line. ftesults of measures of standard kilometer—In the meas- ures of the kilometer the observers always interchanged posi- tions in reading on the bar. The results may then be regarded as free from personal equation except so far as such equation R. S. Woodward—Iced Bar Base Apparatus. 47 may differ for the two ends of the bar. Each section of the kilometer was measured in both directions. The bar was kept in the same position, relatively to the Y-trough, it had when used on the comparator. A measure from west to east on the comparator corresponds then to a measure from north to south on the kilometer. Two series of measures of the kilometer were made; one immediately after the intermediate section stones were set and while the ground was very unstable, and one after the ground was dry and very stable. In addition to errors arising from unstable ground the first measures were subject to some errors arising from delay and temporary stops, which were avoided in the second measures. Accordingly, the first series of measures must be regarded as much less precise than the second. The following table gives the results of these two series of measures. The numerical quantities given are the excesses measured with the cut-off scale over a round number of bar lengths, the number of bar lengths being fifty for each sec- tion and two hundred for the whole kilometer. The first measures were made on Sept. 10 to 15 and the second on Sept. 26 to 30. Results of measures of kilometer. Ist series, Sept. 10 to 15, 1891. No.of Directicn Section Section Section Section meas- of 0™ to 250™ to 500™ to 750™ to ures. measure. 2502" D0 OZ. TEU 10007, O0™=—1000™. mm mm mm mm mm ] NtoS + 6°35 —5°43 +19°08 —29°56 — 0°56 2 Sto N + 6°52 —4°55 +19°37 —19°28 + 2°06 1-2 —O0'17 —0°'88 — 0°29 — 1°28 — 2°62 2d series, Sept. 26 to 30, 1891. 3 NtoS + 6:97 —5°50 ENO? Vos eameyZ! 4 Sto N EON — 5°60 O76 — 2-19), O04 3-4 =—=()al@) + 0:10 = O08) 5 C200 SOP Without attempting to discuss these results here, it may be pointed out that they indicate systematic differences depend- ing on the direction of measurement. These differences agree in sign with those developed in the forward and backward measures of the 100" comparator as explained above. It may be remarked also that the largest differences in the first series are found in the measures of the second and fourth sections where the ground was least stable. 48 LR. S. Woodward—Iced Bar Base Apparatus. From the differences (1-2) and (8-4) of the table it appears that the probable error of one measure of a kilometer is 0°76" from the first series and +0-09"™ from the second series. The second of these probable errors, it may be re- marked, agrees well with the corresponding value deduced from the measures on the 100" comparator, to wit, using the average value for the probable error of one measure of the comparator interval : BOM+61M) ats V/10 = + 0°10"™ It will be of interest in this connection to compare these probable errors of measurement with those obtained with other micrometer microscope apparatus. The apparatus most nearly comparable in this respect with the iced bar appa- ratus are the Repsold bimetallic (zine and steel) of the U.S. Lake Survey and the Brunner bimetallic (copper and platinum) used recently by French geodesists. The best work with the Repsold apparatus, on the Olney base 1879, shows a probable error of +0407" for one measure of a kilometer.* The work of the French on the Paris and Perpignan bases, 1890, 1891, shows +0:67™™ for one measure of a kilometer.+ These larger values are due probably to imperfect temperature indi- cations of the bimetallic apparatus rather than to any material differences of manipulation. An idea of the stability of the end and section marks of the kilometer may be gained from the above table by computing the differences between the mean lengths of the several sec- tions resulting from the first pair and second pair of measures. Thus we have: Mean of first pair minus mean of second pair of measures. Section » 0@ toi 250° —0°58"™ e: PKI ye Se BO) + 6°56 * HOOD. XO —0°50 me (Ore LOO0 +1:32 These figures indicate considerable movements of the mark- ing stones; and it seems not improbable that movements of such magnitude did actually occur, since the stones rose to the surface of the ground and the moisture in the ground varied from the extreme of saturation to the extreme of dryness during the interval which elapsed between the two sets of measures. * Professional Papers Corps Engineers U. 8. A., No. 24, p. 303. + Comptes-Rendus des séances de L’Association Géodésique International du 8 au 17 Octobre, 1891, p. 182. RL. S. Woodward—Iced Bar Base Apparatus. 49 Length of measuring bar.—The most important and diffi- cult operation attending the use of the iced bar apparatus is that of deriving the bar’s length in terms of one of the Inter- national Prototype Meters. As already stated, a preliminary determination of this length was made in July, 1891, just previous to shipping the apparatus to Holton Base, Indiana. The method adopted in this and in most subsequent determi- nations may be briefly described as follows: Six micrometer microscopes were mounted in a straight line at intervals of one meter. The 5™ distance between the two extreme microscopes was measured with Prototype Meter, No. 21, and this distance transferred from the extreme microscopes to the 5™ steel bar No. 17. All comparisons of this kind were made with both the meter and 5™ bars in melting ice. The 5™ bar was mounted in its Y-trough and the meter bar in a wooden box. 40 to 45 kilograms of ice were used for the 5™ bar and 10 to 12 kilo- grams for the meter. Assuming constancy of temperature of the bars under com- parison the precision of the method just outlined evidently depends on the stability of the microscopes used. The first series of comparisons of July, 1891, and several series of February to May, 1892, were made on the office comparator. This comparator was not designed to meet the special require- ments of the case and it did not meet them satisfactorily. The microscopes were too unstable. Their instability was due primarily to the manner of mounting them. They were each suspended by a cast iron bracket from a wrought iron I-beam about 6™ long which is supported at its ends on brick piers. The focal planes of the microscopes fell about 0-5" below the beam. The beam was wrapped with cotton batting and cov- ered with a wooden casing to prevent rapid temperature changes. Resting as the beam does by friction on the piers, it is in general in a state of longitudinal stress, which is fre- quently relieved by vibrations communicated to the piers by vehicles passing in the adjacent street. Changes in this stress produce changes in the curvature of the beam and entail exag- gerated motions in the microscopes. The temperature of the comparing room (which is underground) changes very slowly from day to day when not occupied long by observers or when lighted for short periods. The comparisons in question, how- ever, required occupying the room for some hours per day, and the heat from the observers and the electric lights caused notable changes in the temperature of the beam as well as of the air in the room. These changes no doubt caused more or less irregular displacements of the microscopes. Am. Jour. ScIl.—THiIRD SERIES, VOL. XLV, No. 265.—January, 1893. 4 50 Le. S. Woodward—Iced Bar Base Apparatus. The observations were so arranged as to eliminate the effects of uniform motions of the microscopes. Thus in the first series of determinations the following program was adhered to: 1. Measure of distance between end microscopes with meter, 2. ey i e os with 5™ bar., 3. ce “ “ “ “ “ meter ; the second measure with the meter being made in a direction opposite to that of the first. In later measures on this com- parator the above program was supplemented by an initial and final measure with the 5™ bar. The observations were made by two persons observing simul- taneously at the respective ends of either bar. The observers also exchanged positions in all cases to eliminate personal equation. The determinations made in the manner just described showed large ranges, amounting to 1/200000th part at the maximum ; and with the hope “of overcoming the effects of the irregular motions of the microscopes a different method was tried with the same comparator. The essential feature of this method consists in the use of an intermediary 5™ steel bar subdivided into meter spaces. This bar, known as No. 18, is similar in form to No. 17, except that it is cut down to the mid depth at four intermediate places as well as at its ends. The lines subdividing the bar into meter spaces are ruled on eae iridium plugs. This bar was mounted in the steel -trough where its flexure could be controlled in the same way as that of bar No. 17. The sub-spaces of No. 18 when packed in melting ice were determined by direct comparisons with Prototype Meter No. 21. Three series of six measures each of the sub-spaces, and hence of the whole length of the bar, were made. In the intervals between the first and second and the second and third series, bars 17 and 18 were compared. For this purpose No. 17 was mounted in an auxiliary wooden trough similar to the Y-trough. Notwithstanding the di- minished time-interval during which dependence on the sta- bility of the microscopes was required by this process, the results attained were still too erratic to give contidence. The range in values for the metric sub-spaces of No. 18 rose to 1/200000th part and in the values for the whole length, or sum of these spaces, to 1/300000th part; and these ranges appeared to be directly referable to the large progressive, and frequently large sudden, movements of the microscopes. Such being the unsatisfactory quality of the results attained on the office comparator, it was determined in June, 1892, to build a new comparator designed more especially to meet the f. S. Woodward—Iced Bar Base Apparatus. 51 requirements of the iced bar apparatus. This comparator was constructed in a lot adjacent to the Survey Office. Briefly described it consists of six brick piers resting at intervals of a meter on a foundation of six cubic meters of well rammed concrete. The foundation and the piers are set in Portland cement and weigh about twelve tons. The foundation, which rises to near the ground surface, is covered to the depth of a decimeter with sawdust. Each pier carries a micrometer microscope. The latter and their connections with the piers are wrapped heavily with cotton batting. The meter and 5™ bars were moved under the microscopes on portable tracks sup- ported on posts isolated from the piers. The track for the 5™ bar was that used in the field, and the mode of handling this bar was precisely the same in all respects as that followed in measuring a line. The microscopes as mounted on this comparator proved to be very stable notwithstanding the fact that they were subject to the daily range in air temperature except so far as they were protected by cotton batting wrappings. The effect of the observers’ presence near the comparator was undoubtedly less than in the office comparing room, and the use of artificial light was avoided entirely. The program followed in the use of the new comparator comprised three measures of the distance between the end microscopes with the meter and two measures with the 5™ bar in each set of observations. The measures with the meter were made in opposite directions alternately along the com- parator. Twenty sets of observations were made with the 5™ bar in each of its two orientations relatively to the Y-trough and microscopes. The consistency of the results attained leaves little to be desired. The probable error of a single determination of the length of the 5™ bar in terms of the Prototype is +1”-8 from one group of measures and +147 from the other. The range in the one ease is 12:3 and in the other 8/5. The following table gives an abstract of the results obtained in the manner described above for the length of the 5™ bar. The values given are subject to corrections for flexure of the’ 5™ bar, which, however, cannot exceed a few tenths of a micron. The probable errors are those which come from the discrepan- cies between the individual and mean results of a group of determinations. Each result is derived from an equal number of measures with the meter and 5™ bars in their two different orientations. The first, second, and third results were obtained from the Office comparator, the third one depending on the method wherein the auxiliary bar, No. 18, was used. The fourth result was obtained from the new comparator. 52 L. S. Woodward—Iced Bar Base Apparatus. Summary of results for length of B,,. No. of Date. Measures. Mean length of bar. Jauliy, ISON eae Baie Load 10 5™— 11-9414 Heb. and March, 1892 .--- 20 5 —15 °2+0 ‘6 April and May, 1892-..-- 18 5 —11 ‘71556 July and August, 1892 _- - 20 6 —16 ‘8+0 °3 Without desiring to discuss these data here, it may be said that so far as is known at ‘Presenit the probable errors are fairly trustworthy indices of the precision of the several results. The range among them is but little in excess of the miilionth part of the bar’s length, and is no greater than the probable errors would lead one to expect. It may be stated also that the external air temperature varied for the different groups of comparison from 5° to 40° C. The average air temperatures for the two most important groups, namely, those of February and March, 1892, and July and August, 1892, were about 5° C. and 35° C. respectively. Hence it does not appear that the bars in ice were affected appreciably by the external air temperature. Finally, it should be said that a systematic difference in the length of the bar, according as the one or the other of its ends is to the right in the Y-trough, is indicated by each group of compari- sons. This difference appears to be an inequality of relative personal equation of the observers at the two ends of the bar, and may be due to the considerable inequality in widths of the terminal graduation lines. Concluding remarks.—The question may be asked, does the bar take the temperature of melting ice when fully packed i in it? I am unable to give a decisive answer to this question at present, but there appears to be no reason to suppose that it takes a materially different temperature. Repeated observa- tions on mercurial thermometers placed in the ice alongside the bar show that they read zero within the unavoidable errors of a few hundredths of adegree. ‘That the bar assumes a fixed length within very narrow limits is, it would seem, demon- strated by the small range among the measures of the 100" comparator and the kilometer sections referred to above, and especially by the recent work on the new comparator. This latter work appears to justify the conclusion that the mean of four determinations of the bar’s length in terms of the Proto- type meter, made in the manner described above, cannot have a greater pr robable error than one micron. It is evident there- fore, in view of the unavoidable errors of observation in such work, and in view of the fact that the bar’s expansion is about 55” per degree Centigrade, that there is a very small margin for change in the bar’s length. R. 8. Woodward—Iced Bar Base Apparatus. 53 The time required for the bar to acquire a sensibly stable length is less than ten minutes. The rate of temperature- change is so great in the early stages of freezing that ninety per cent or more of the contraction of the bar occurs within a minute after it is well surrounded by ice. The corresponding time required by the Prototype meter to reach a stable length appears to be less than five minutes, which is less than the time essential to properly pack it in ice. A query may also arise as to whether the bar, resting as it does with considerable friction on the vertical adjusting screws of the Y-trough, may not change length by reason of longi- tudinal stress communicated by the trough. In answer to this query it may be said that the experiment of putting the trough alternately under tension and compression in quick succession has been tried on several occasions without disclos- ing any effect on the bar. With regard to the precision attainable in the measurement of a line with this apparatus, it would appear that the error of operation may be rendered insignificant in the mean of a few measures of a line, so that the probable error of the mean length may be diminished to that of the bar when expressed as a fraction of its length. It appears practicable to de- termine that length with a probable error not exceeding 1/5000000th part, and this, therefore, would appear to be an attainable precision in the measurement of a line with the apparatus. Although the use of this or similar apparatus is not to be recommended for primary bases in general, since it gives a needless precision, it will compare favorably I think on the score of economy with any of the earlier forms of apparatus which have given a precision approaching the millionth part of a measured line. The proper function, however, of the iced bar apparatus appears to be that of an intermediary between the lighter and cheaper forms of base apparatus and the stan- dard meter. By means of this bar it appears practicable to standardize long steel tapes so accurately that they will give all needful precision for bases in general at much less cost than other forms of apparatus.* Office Coast and Geodetic Survey, Sept. 15, 1892. * Experience of the author in the use of 100™ steel tapes with mercurial ther- mometers to give temperature, on the Holton Base, 1891, shows that the length of such a tape can be determined with a probable error not exceeding 1/2000000th part, and that the probable error due to errors of operation and temperature in the mean of n measures of a line & kilometers long need not exceed + Qmm pra 54. JS. OC. Graham—Enperiments with an Artificial Geyser. Art. V.—Some Experiments with an Artificial Geyser ; by JAMES C. GRAHAM. As aresult of observations during his travels in Iceland in the summer of 1846, Professor Bunsen advanced the explana- tion* of the eruptions of the Great Geyser which has been almost universally accepted since then. In 1847,+ there ap- peared an article in which Professor Bunsen’s views were dis- puted and it was in answer to this article that Professor Miller published in 1850 the first account of which I ean find any record, of experiments with an artificial geyser.t Since that date artificial geysers have been often constructed and exhibited, the most com- J plete descriptions in English of such gey- sers, being found in Professor Tyndall’s “Heat as a mode of Motion” (Appleton, 1865, p. 189) and in a description of Miller’s experiments in Hayden’s Report for 1878 of the U. 8. Geological Survey 2 (p. 420). . 2 In all of these experiments, however, the artificial geyser has not been con- structed to explain geyser phenomena in ye general but has been restricted to an : imitation of the Great Geyser of Iceland. This geyser is peculiar in having the boil- ing point reached first, not at the base a of the tube or throat, but at a position considerably above this. It is doubtful if this peculiarity has been repeated in any =| 4 geyser which has been elsewhere studied. ai In my work, therefore, I have not applied — heat at an intermediate point of the tube, 4° but only at the base. The description of ll my apparatus is as follows: \ It consists (fig. 1) of a glass tube, 7, surmounted by a funnel, g, and terminat- ing in an iron cylinder, a. This cylinder is immersed (to the line /) in a bath of mercury contained in another iron cylinder, 6; c and d are thermometers, regis- tering the temperature of the mercury and of the geyser fluid respectively; ¢ is a mercury gas-cock, so arranged that an ile * Pogeendorff, vol. lxxil, p. 159. + Die Fortschritten der Physik im Jahre, 1847, dargestellt von der physikal- ischen Gesellschaft zu Berlin, p. 92. + Poggendorff, vol. Ixxix, p. 350, 1850. J. CU. Graham—Fxperiments with an Artificial Geyser. 55 increase of heat causes an expansion of mercury in the bulb below, thereby decreasing the heat by cutting off the gas. The ob- ject of this device is to maintain, as nearly as practicable, a constant temperature inthe mercury. The whole is supported upon a frame not shown in the figure. The important dimensions of the apparatus are : Internal diameter of inner cylinder -_-_-.- .--- 0-089" : height i SM ie Ra tel eR 0°136™ i diameter, Ofent ull ies ere sent are 0:021™ PECTS tObetube eo ee ee uke Na, el 1:44™ Hersht toy which cone is filled? 2522252 2_* 22227 0°035™ ovalbherghtzotdurdscolummny Sessa. eae tT With this apparatus we are enabled to get not only qualita- tive but quantitative results to a large extent, for all the factors are nearly constant, and where variable, the amount of varia- tion can be detected. The object of my experiment was to see if any light could be thrown upon the subject of “soaping geysers” by the study of an artificial one. But before considering this subject, I wish to mention an observation which seems to me to give a eriterion, judged by which certain geysers can be proven not to operate upon the McKenzie principle. It will be recalled that Sir George in explaining the phe- nomenon of an eruption supposed a tube communicating with a subterranean cavern in the way indicated in the accompany- ing sketch, fig. 2. The water is kept in the tube at the level indicated, by the steam pressure in A, arising from the heated water B. An eruption takes place when the pressure in the cavity becomes great enough to lift the column in the tube sufficiently to cause an overflow and thus to lessen the pressure of the col- umn. By forcing the tube of my artificial geyser part way 56 J. G. Graham— Experiments with an Artificial Geyser. down into the iron cylinder, a geyser is formed of practically the same type that Sir George’s theory requires. When this is done, this change is at once observable in the eruption. They are unpreceded by steam bubbles. It is evident that this must be so; for the peculiar form of the tube and chamber are of no avail in Sir George’s theory unless the temperature of the water reaches the boiling point before the water-level in the subterranean chamber has been forced down to the opening of the tube into the cavity. And until this level is reached no steam bubbles of any consequence can escape. The conclusion which I would draw would be that those geyers in which the eruptions are markedly preceded by bubbles can- not be classed as “* McKenzie’s.” To turn now to the main subject of this paper, that is the effect of soaping geyers. It has long been thought that by throwing stones or putting soap into a geyser, a premature eruption could be brought on in the cases of geysers erupting periodically, and that in some cases, hot springs, not known to be active, have by this means been caused to throw out the water in their basins in geyser- spouts. It is evident, however, that this matter is not capable of absolute proof; for, as none of the geysers are perfect in regard to the equality of their periods, we can never say posi- tively that the geyser would not have erupted when it did if it had not been soaped. Or, in the case of forced eruptions of hot springs, it might be considered that these springs were geysers with periods so long that the nature of the spring was now for the first time revealed. To be sure that such would be the case in many instances is improbable but not impos- sible, especially as but comparatively few springs have been successfully experimented upon. Jf now, in the artificial geyser, it can be shown that with the same conditions as to the amount of fiuid, heat, barometric pressure, etc., the periods of eruption are shorter when the soapy fluid is used than when the fluid is simply water, it will then be conclusively proven that the soap does cause a premature eruption. The question of why it so acts, may then be attacked. There are many difficulties in the way of making these seemingly simple observations. It is necessary that the amount of fluid in the geyser should be the same in all observations; but owing to splashing and evaporation, this has a constant tendency to vary. The splashing was provided against by filling the geyser not sim- ply to the top of the tube, but part way (3°5™) up the funnel as well, which had the effect of deadening the eruption. The error due to evaporation was provided against by adding a determined amount of fluid at the end of each eruption. By J. O. Graham—Experiments with an Artificial Geyser. 57 this means the error is made a nearly constant one, and the height of the column is not affected. The question of a constant supply of heat cannot be entirely solved, or at least could not be with the apparatus at my con- trol, But by the aid of the self-regulating gas-eock I was able to keep the supply nearly constant, and by means of many readings of the thermometer immersed in the mereury bath, a comparison could be made in the cases of different eruptions which I think are sufficiently accurate and definite. The error of barometric pressure variations was overcome by making observations on various days and comparing those in which the heights of the mercury columns were nearly the same. There were also many minor factors, such as the temperature of the room in which the observations were made, which had to be taken into account and eliminated when possible. In making the statement of the results of these experiments, only a few from several hundred observations will be given ; those in which the various conditions were most favorable to accurate determinations. In Tables I and III the fluid used was ordinary water from the city reservoir. In Tables II and IV it was a solution of Ivory soap in water, of such strength that it was of a molasses-like consistency when cold, but of course much more fluid when warm. Tempera- Temp. Temp. Temp. Temp. ture of Hg. at Hg. atter aq at aq. after Time of erupt. Period between room. erupt, crupt. erupt. erupt. Vela SU INEay tS) erupts. Water. is Barom., 30°24 in. Dili 107°5° 104°5° 103°2° 94° 11 35-25 6-30 21°5 107°5 104 8 103°2 94. 40-25 5-25 21°5 107°2 104°5 103°2 95 46-30 . 6-05 215 107°2 104:°5 103°2 95 52-50 6-20 21-5 LOM? 104°3 103 2 94 59-15 6-25 Soap and Water. IE Barom. 30:2 22 J0T5 104°7 103 BLE) ]4— 5-15 22°5 107 104:7 103 91°5 19-10 5-10 22°5 107 104°6 103 91°5 24-20 5-10 22°5 107 104°7 103 SS) 24-55 5-36 22 107 104°6 103 Died) 35-10 5-15 22 107 104+ 103 BOS) 40-20 5-10 Water. DBE, Barom. 29°74 22 1065 —103°8 1031 94 10 21-05 7-50 22 106°5 103°5 103 93 29 7-55 22 106°5 103°8 103 94. 37-10 8-10 22 106°5 103°8 103 94 44-40 7-30 22 106°5 103°7 103 94 52-35 7-55 22 106°5 % 103 94 0-05 7-30 Soap and Water. Vi. Barom. 30°§ 215 106°5 103°5 103°1 92 9 52-20 6-10 21°5 106°5 103°7 103°] Sil 2) BNSF) 5-55 21-5 106-5 103°5 103°1 wy 10, 4-25 . 6-10 21°5 106°5 103°5 10371 91 10-15 5-50 58 J.C. Graham—EHxperiments with an Artificial Geyser. In these tables although the conditions are not precisely the same, it is evident that in those cases in which the soap was used, the periods between the eruptions were much shortened. The differences in the temperature of the room and mercury, and the changes in barometric pressure, are so slight as to be unworthy of notice, or in a direction contrary to produce the obtained result. It is also noticeable that the soap solution is cooled much more after each eruption than is the case with pure water. This is due to the fact that as the periods are shorter, convection and other causes, could not operate so com- pletely to heat the water in the geyser throat, and this cooler water in rushing down at the end of the eruption, lowers the general temperature. This factor also acts against the tend- ency of the soap solutions having shorter periods, as it requires a greater elevation of temperature at each eruption than is required in the case of pure water. I think that these observations show conclusively that soap- ing geysers does have a tendency to shorten their periods. The question which now confronts us is: How does it pro- duce this effect? I will confess at once that I have not solved this problem very satisfactorily; but I have at least shown that some theories which have been advanced as to the modus operandi, cannot hold. It is evident that to bring about an eruption, what must be done is to cause the water to boil at some point in the tube ; and any effect which the soap has upon the boiling of the geyser water may be a factor in the solution of the problem, provided only the effect is in a positive direction. By being in a positive direction, I mean having a tendency to hasten, rather than to retard, the boiling. What these various effects are, I will now proceed to consider. First, as to the weight of the column. If the specific gravity of the soapy water were much less than that of the water alone this would lessen the pressure and so lower the boiling point for any given depth. By determination, I found that considering the water used of a specific gravity of 1, the specific gravity of the soap solution was 100454. The deter- minations were in both cases at a temperature just below the boiling point and the fluids were those actually used in operat- ing the geyser. The effect of the difference of specific gravities would therefore be negative as regards hastening an eruption. Second, as to the boiling point itself. In this respect there was no difference, it being 99° C. for both. These observa- tions were made at the same time and with the same ther- mometer, etc., to avoid all chances of error. J. 0. Graham— Experiments with an Artificial Geyser. 59 Third, as to the specific heat. If the specific heat of the soap solution were less than that of the water, less heat would be required to bring a given amount to the boiling point, and with a constant supply of heat, less time would be required. This observation it was impossible for me to make with any great accuracy, but from the results of my experiments, I should say that there was no appreciable difference between the two specific heats. Fourth, as to the retention of heat. In the tables concern- ing the periods of eruption, it was noticed that the tempera- ture was lowered more after an eruption in the case of the soap and water than in the case of the pure water. As the boiling point was the same in both cases (compare Tables III and IV) it was considered that this was due to the columns above being less heated in one ease than in the other. This at once suggests a possible explanation. The heat is retained in the lower part of the tube where it can be utilized in causing the fluid to reach the boiling point, and so not wasted in rais- ing the temperature of the whole column. How, then, is this heat retained, or conversely, how is the heat lost in the case of the water weyser / Convection is, of course, the principal method by which heat is conveyed from the lower part of the tube to the upper portion. If the. viscosity of the fluid retards convection, this then would cause the heat to be retained below. To test this matter, I constructed a piece of apparatus by which a column of water was heated at the base only, and the temperature attained by the water in the upper part of the tube could be read at given intervals of time. By changing the fluid to soap and water, the influence of the viscosity upon convection, at least as far as it affected my problem, could be determined. After a number of experiments with the fluids at high temper- atures, I was somewhat surprised to find that the thermometer in the soap solution showed in every case, a slightly greater degree of heat than in the case of the water. That is, vis- cosity did not seem to retard the escape of heat by convection. Hence convection cannot be the factor sought. In all eruptions of the geyser the final out-rush of the water is preceded by the rise of bubbles of steam (and of air, possi- bly, to some extent), through the column of water. If these bubbles are retarded in their ascent by the viscosity of the fluid, they will give out more heat in the lower part of the tube and’ so carry less to the upper. Accordingly, I devised an apparatus to measure by the chronograph, the time required for the bubbles to pass a given distance thr ough the different liquids against the force of gravity. The average of about twenty five readings in each fluid showed that the time re- 60 J. C. Graham— Experiments with an Artificial Geyser. quired was the same in both cases to the hundredth of a second. From these experiments I am forced to the conclusion of Mr. Arnold Hague, which he states in his paper entitled ‘“Soaping Geysers” read before the New York meeting of the American Institute of Mining Engineers in February, 1889. ‘“‘ Viscosity must tend to the retention of steam within the basin, and, as is the case of superheated waters, where the temperature stands at or above the boiling point, explosive liberation must follow. All alkaline solutions, whether in the laboratory or in nature, exhibit, by reason of this viscosity, a tendency to bump and boil irregularly. Viscosity in these hot springs must also tend to the formation of bubbles and foam when the steam rises to the surface, and this mixture aids to bring about the explosive action, followed by a relief of pressure, and this to hasten the final and more powerful display.”’ The retention of steam referred to in the above quotation is an entirely distinct phenomenon from that of the interference in the rise of steam bubbles investigated in my experiments. It is an interference with the actual formation of the bubbles rather than with the rise of them after forma- tion. That such an interference does actually take place is also shown by the fact that the bubbles liberated in the soap geyser are far less numerous than in the case of the water geyser. Also, when they occur in the ease of the soap geyser, they are large and of sudden formation, which would tend to cause an overtiow of the basin and thus to relieve the pressure. In these facts then in regard to the formation of the steam bubbles, I take to He the main explanation of the phenome- non, believing the surface bubbles to be a much less important factor. Physical Laboratory of Wesleyan University, Middletown, Conn., Oct. 12, 1892. H. A. Newton— Andromed Meteors, ete. 61 Art. VI.—QObservations of the Andromed Meteors of No- vember 23d and 27th, 1892 ; collected by H. A. Newron. On the evening of Nov. 23d there were seen at various places in the United States shooting stars which radiated from Andromeda, and which were apparently fragments from the Biela Comet. At New Haven, Conn.—Dr. Elkin was in the open air for some minutes about seven o’clock on the evening of Nov. 238d. The sky was clear and he feels confident that if there had been a great number of shooting stars, he would have cer- tainly seen them. About a quarter past ten o’clock he was informed by Mr. Chase that the meteors were coming in unusual numbers. For a time they came so as to furnish about ten per minute visible by one observer. Only a part of the sky wasclear. Most of the trains were short, not exceed- ing four degrees in length. Very few were as bright as stars of the first magnitude. Dr. Chase of the Yale Observatory was walking across the Observatory grounds between ten o’clock and a quarter past ten and in seven minutes counted 16 meteors. In the twenty min- utes following hesaw enough more to make in all more than 100 flights, that is, in 20 minutes he saw more than 84 meteors. Most of them were faint and had short tracks. Very few left trails. One however left a trail that was visible during 15 seconds. The radiant was very close to Gamma Androm- ede. About 10" 35™ he and Dr. Elkin gave up counting, as the sky was nearly overcast and therefore the counts were unsatisfactory. Mr. Van Name, the University Librarian, counted 50 in five minutes between 10? 50™ and 102 55™. He was looking southeast. The direction was almost straight down. There were no very bright ones, though the train of one lasted a second. Observations of Meteors at 1905 N St., Washington, D. C. —Prof. J. R. Eastman writes: While crossing the street at the corner of N and 19th sts., I saw a meteor near @ Cassio- pese, quickly followed by two more. In a short time I counted 15 and from 10" 24™ to 10" 43" I counted 102 meteors. From 10° 58" to 112 11™, 111 were counted, and from 11 19™ to 11° 41™ I counted 114, or, in all, 827 meteors in 53 minutes by one observer. They were scattered all over the sky wher- ever I could see, but in a general way they seemed to diverge from a point about half way between 7 Andromede and ; Cassiopese and near @ Persei. The codrdinates of this radiant 62 HH. A. Newton— Observations of the would be about 1” 35" and +51°. Owing to the wide disper- sion of the bodies the location of the radiant was very difficult and, at best, could be only approximate. Several meteors were quite bright, and one left a bright train showing brilliant red and green tints. The behavior of several meteors gave the impression that they were not more than 100 yards from the observer; I observed this peculiarity in several instances in the shower of Noy. 27, 1872. Prof. Eastman also communicates the following notes by Mr. D. Horigan, watchman at the new Naval Observatory : Some meteors appeared soon after dark. At 7 were quite numerous. At 8", increasing in number. At 9", still increas- ing, several seen at once. 9" 80™, still increasing, some leav- ing trains of red and orange tints. 9" 40", too numerous to count. Radiant apparently east of “chair of Cassiopes.” 10 0" to 10° 45™ still increasing. Began to decrease some- what atter 11° 25". About 11° 25™ quite a cluster fell from about 15° below Polaris to the horizon. At midnight many visible but apparently growing fainter. 0» 20™, reduced to counting scale but rather late to begin now. 1” 0", many still falling, but number decreasing. 3 0™, some to be seen yet. After 3" 0™ A M. on the 24th made several observations and found more or less falling till daylight. At Griswold, Conn.—Proft, A. W. Phillips was on the even- ing of Nov. 23d riding in an open carriage in Griswold. Between 8" 15" and 8" 50" he counted nearly 200 shooting stars. Most of them were faint and had short paths; a few were brilliant. The radiant was in Andromeda, but was not accurately located by him in the constellation. At times they came in rapid succession, then frequently a lull. After reach- ing home (8" 50™) he saw through a window that the display continued. About 9" 10™ it became cloudy, and after that more were seen by him. At Meriden, Conn.—Mr. E. W. Abell reports that he and his two sisters were at ten minutes past eight looking atten- tively at Jupiter for at least three-quarters of a minute and if there had been an ‘unusual display at that time they would certainly have seen it. At 9" 26™ he and his mother went out upon an errand and at once saw the shooting stars “ falling quite rapidly, sometimes almost as fast as we could count.” A regular watch was shortly afterwards arranged for, four per- sons watching each a quarter of the heavens, and counting aloud to prevent duplication. In the five minutes between 10” 7” 30* and 10" 12™ 30° there were seen to the south 29, to the west 18, to the north 35, and to the east 52 meteors; in all 134. .A few minutes later two of the party looking to ‘the Andromed Meteors of 1892. 63 east counted in five minutes (beginning about 10" 20™) 71 meteors. Mr. Abell then began to locate the radiant. It was between Aries and Andromeda but the meteors did not fall so numerously as before and it took five or ten minutes to see three or four start near enough to the radiant to locate it approximately,—a little to the north of the triangle,—between Aries and Andromeda. A sketch of the stars made by Mr. Abell places the radiant near R. A. 1° 40™ and Dec. + 35°. The sky was very clear all the time. At Albuquerque, NV. M.—Rev. M. R. Gaines writes that at a little before ten o’clock (presumably by time seven hours from Greenwich) the meteors were quite frequent, — he “counted 100 in a few minutes, as many as three at a time being visible.” No very large ones, and none with trains of any great durability were noticed. He was told that the shower was noticed two hours earlier than the time when he first saw it. At eleven o’clock the rate was somewhat less than when first noticed, but meteors were still frequent at that hour. At other places.—F rom the newspapers we learn that Profs. Young, Rees, Davidson, and Hale, and others observed the dis- play. It seems better to wait for their responsible accounts than to incur the risk of perpetuating the unavoidable errors of newspaper reports. This display seems to me to be the successor of the sprinkle observed at New Haven and Germantown on the 24th of November, 1872 (this Journal, II, vol. v, p. 53) rather than of the more brilliant display seen in Europe three days later, that is Nov. 27th, 1872. There were no Andromed meteors seen so far as I know on evenings of the 24th, 25th or 26th, though in New Haven, and generally in the eastern part of the United States the skies were clear. On the night following Nov. 27th it was generally cloudy in the United States., Shooting Stars in Mexico, Nov. 27th.—Mr. A. J. Newton and Mrs. A. G. Dana left Torreon in the afternoon of Nov. 27th en route for New Orleans. Between eight and eleven o’clock they saw through the windows of the ear (single thick- ness of plate glass) a large number of shooting stars. It seemed hopeless, says Mrs. Dana, to count them. They came two and more at a time, and they formed a continual display of celestial fireworks. 64 A. E. Foote—WNotice of a Meteoric Stone. Art. VIl.—Preliminary Notice of a Meteorie Stone seen to fall at Bath, South Dakota; by A. E. Footr.* With Plate III. ON the 29th day of August, 1892, about four o’clock in the afternoon, while Mr. Lawrence Freeman and his son were stacking upon his farm two miles south of Bath, they were alarmed by aseries of heavy explosions. On looking up they saw a meteoric stone flying through the air followed by a cloud of smoke. Its course was easily traced to the point where it fell within about twenty rods from where they were standing. ‘The stone penetrated the hardened prairie to a depth of about sixteen inches and when reached it was found to be so warm that gloves had to used in handling it. Three small pieces of an ounce or two each had apparently been blown off by the explosions, but the stone still weighed 463 lbs. One of these small pieces was found by some men not far dis- tant and was broken up and distributed among them. The explosions were plainly heard by a large number of people at Bath, two miles away, and at Aberdeen, nine miles away, it sounded like distant cannonading. The exterior of the stone presents the usual smooth black crust. The interior is quite close-grained resembling in texture the stones from Mées. The iron is abundantly disseminated through the mass, and although the grains are small they are easily distinguished and separated on pulverizing. Preliminary tests made by Mr. Amos P. Brown of the mineralogical department of the University of Pennsylvania prove the presence of nickel and cobalt in considerable quantity. Plate III shows the form of the stone and thesize is indicated by the metrie scale at the side. An affidavit signed by Charles Freeman (before H. T. Root, Notary Public) stating the facts of the fall, is in the hands of the writer to whom the stone was sent. * A verbal communication on the above was made before the Academy of Natural Sciences of Philadelphia (November 23, 1892.) Chemistry and Physics. 65 SCIENTIFIC INTELLIGENCE. I. CHEMISTRY AND PHYSICS. 1. On the Influence of Foreign substances on the Form, the Size and the Purity of Crystals separating from a solution.—In continuation of his investigations on isomorphism, ReraERs has studied the influence, in a solution from which crystals are separat- ing, of the presence of foreign substances upon the form,. the size and the purity of these crystals. It is well known for exam- ple that sodium chloride, which crystallizes in cubes from solution In pure water, separates in octahedrons if urea be present. Lead nitrate which separates from an aqueous solution in white porce- lain-like crystals, appears in perfectly clear, transparent crystals if nitric acid be added to the solution. Ammonium chloride which is deposited from solution in water in insignificant grains and skeleton-like crystals, separates in crystals a centimeter long if the solution contain some ferric chloride. If a cubo-octahe- dron of sodium chloride be placed in a concentrated aqueous solu- tion of salt, the author observes that the cubic faces grow faster than the octahedral, and so produce finally a cube; while a simi- lar cubo octahedron placed in a solution containing urea, becomes finally an octahedron by the more rapid growth of the octahedral faces. The cause of this difference lies evidently in a contact difference in the two cases between the crystal-faces and the liquid; a change in fact in the capillary attraction. Adhesion depends upon the nature of the liquid as well as upon that of the solid, the same liquid acting very differently upon different solids. Moreover the cubic and the octahedral faces of the cubo-octahe- dron are physically quite different; this difference being often evident in their difference of luster. Sodium chloride gives cubes in pure water, or in water containing ferric chloride or a lead hal- ide; but it yields octahedrons in water containing urea or chro- mium chloride. The potassium halides give cubes in all these cases, except where the solution contains a lead halide, when the crystals are octahedrons. Potassium chloride however, which generally crystallizes in cubes, gives cubo-octahedrons if the solu- tion contains urea. Ammonium chloride and bromide, which separate in trapezohedrons from an aqueous solution, crystallize in cubes if the solution contains urea or chromium chloride ; while if it contains ferric chloride, the ammonium chloride separates in cubes and the bromide in trapezohedrons ; the reverse being the case when the solution contains a lead halide. Ammonium iodide crystallizes in cubes from aqueous solutions and from those con- taining urea, while the crystals are octahedrons if the solution contains chromium or ferric chloride or a lead halide. As to the size of crystals, the author concludes that every crystal has a maximum limit, beyond which there is no further growth. This Am. Jour. Scl1.—THIRD Series, Vout. XLV, No. 265.—January, 1893. 5 66 Scientific Intelligence. maximum.is variable somewhat with the conditions, the volume of the solution attecting the result, up to a certain point. In proof of this he exposed crystals of alum and of magnesium sul- phate, after they had reached this maximum size, to strongly supersaturated solutions for several days, without any result. This maximum size of a crystal, however, depends upon the pres- ence of foreign substances in the solution, a crystal of salt being larger when obtained from a solution containing cupric chloride, —Zeitschr. physikal. Chem., ix, 267, April, 1892. G. F. B. 2. On the Resolution of Lactic Acid into Optically active Constituents.—Although the asymmetric carbon theory of Van’t Hoff was suggested to him by the isomerism of lactic and sarco- lactic acids, no experimental proof has until now been given that inactive lactic acid is actually composed of two optically active lactic acids. This proof is furnished by Purpre and WatkeEr, who have effected the resolution of lactic acid by fractional crys- tallization of the strychnine salt. Commercial lactic acid was diluted and boiled with water to convert the anhydride present —about 31 per cent—into acid. In the calculated quantity of this acid 460 grams of strychnine were dissolved, and the neutral solution thus obtained was submitted to fractional crystallization. Three crops of crystals were obtained which were dissolved sepa- rately in water and treated with ammonia in slight excess. The filtered solution made up to the same concentration gave rotations in a 200™" tube of + 5°46°, +4°83° and —1°33°. The first solution was boiled with zine oxide and fractionally crystallized. The first crop of crystals proved to be the pure zine salt of levo-lactic acid, and gave a specific rotation [@|)= + 5°63. The rotation of the acid is opposite in direction to that of its salts. The mother liquors were converted into zinc salts, and by successive crystallization pure zine dextrolactate was obtained having a specific rotation [a]) = — 5°71°.. By mixing equal weights of the solutions of these two zine salts, the authors obtained a solu- tion which was optically inactive and which deposited crystals of ordinary zine lactate-—J. Chem. Soc., 1xi, 754, Aug. 1892. G. F. B. 3. On the new element Masrium.—tIn examining a native fibrous alum from Egypt, Ricamonp and Orr have detected what appears to be a new element. The alum also contained from 1:02 to 3°63 per cent of cobalt. To extract the new sub- stance, 100 kilograms of the mineral were dissolved in water, acetic acid and sodium acetate were added, and hydrogen sulphide was passed through the solution. A white precipitate was thrown down, which was filtered off, well washed, extracted with dilute hydrogen chloride, boiled with aqua regia, diluted and filtered. On cooling a little calcium sulphate separated. This was re- moved and the solution was evaporated to dryness, taken up with dilute hydrogen chloride and precipitated with ammonia. The washed precipitate was dissolved in sulphuric acid and crystal- lized from 50 per cent alcohol. , OFFER EQUAL TO THE BEST EVER PRESENTED for the consideration of an intelligent and cultured class of American readers, vz. : $13 .00 LITTELL’S LIVING AGE, One Year, Postpaid, - - - Hae eee $8.50 RIDPATH’S HISTORY OF THE U.S. OF AMERICA, - = This splendid offer ts open to all subscribers, old and new alike. ‘RIDPATH’S HISTORY OF THE UNITED STATES,”’ _ by Jonn Crark Rippatu, LL.D., author of the “History of the World,” etc., has received the emphatic _ endorsement of leading educators and of the press of America, Prof. M. J. Wuitney, Houghton, Mich., says, ““ Your history of the United States is the best work upon the _ subject that has ever come under my observation.” The historical charts alone are worth the price of the book. _ Hon. Epmunp H. 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Send for descriptive circulars. ; The prices given in the above “OFFERS” zuclude postage on THE Livinc AGE only. The book must be _ sent at the subscriber's expense. E; _ THE Livine AGE is published weekly at $8.00 a year, free of postage. I@- TO NEW SUBSCRIBERS for the year 1895, remitting before Jan. 1, will 2 be sent gratis the two October issues containing a powerful story by Frank Harris, editor of THE FoRTNIGHTLY REVIEW, entitled PROFIT AND Loss, and also the numbers of 1892 pub- _ lished after the receipt of their subscriptions. 7 Ij@- The publishers continue their popular clubbing arrangements whereby one or more A other periodicals may be obtained at greatly reduced prices. _ _&@ Clubbing rates and circulars more fully describing the history will be sent on appli- Bcstion: Sample copies of THE Livinc AGE 15 cents each. Address LITTELL & CO., 31 Bedford St., Boston. CONTENTS. paw MN Art. IL—The Age of the Earth ; by CLARENCE Kine! With ates Tiand Tyco si 4c ere oe al II.—Tertiary Geology of Calvert Cliffs, Maryland; by Gut- cep | BERT -D, HARRIG: ¢ 2 .t 20) Sie ee II.—*‘ Anglesite” associated with Boléite; by F. A. Genta 82 : : TV: —Preliminary Account of the Iced Bar Base Apparatus of the U. 8. Coast and Geodetic Survey; by R. 3S.” WOODWARD (002°. 00) Se i Sonia SE) at ar as ee 38° V.—Some Experiments with an Artificial Geyser; by J. ©. GRAHAM 300 20 2 A oe ee a 54 VJ.—Observations of the Andromed Meteors of Noy ember = \ 23d and 27th, 1892; by H. A. Newron__-.____..- jst VITI.—Pr eliminary Notice of a Meteoric Stone seen to'fallat — | Bath, South Dakota; by A. E. Foorr. With Plate I 64 | VIIL—Appenpix—New Cretaceous Bird allied to Hesper- poms: ‘by,O,C, Marge lie. oh 20 Fe Dai eee 28h. IX.—Skull and Brain of Claosaurus; Dy 0. C. MareE as With Plates TV and (Viii.00> Spi a \ eels ee _ SCIENTIFIC INTELLIGENCE. Chenistry and. Physics—Influence of Foreign substances on the Form, the Size and the Purity of Crystals separating from a solution, RrTGpRs, 65.—Resolu- tion of Lactic Acid into Optically active Constituents, PuRDIE and WALKER: New element Masrium, RicuMonp and OFF, 66. _ Freezing points of very diinte Solutions, RaouLt, 67.~Chemical Lecture Experiments, G. 8. Newt: Color Photography, M. G. Lippwan: Infra red spectra of the Alkali Metals, B. W. Syow, 68.— Magnetic effect of the Sun upon the Earth, W. THomson: Sound: and Music, J. A. ZAuM, ‘69.. ‘Geology and Mineralogy—View of the Ice ‘Nee. as One Glacial Epoch, 70. aE tocene History of Northeastern Iowa, W. ap McGszz, 71.—Note on the paper in the November No. of this Journal on ‘‘ A New Oriskany Fauna in New York,” S. T. BARRETT: Subdivisions of the Azoic or Archzan in Northern Michigan, M. EH. WApsworta, 72.—Geological and Natural History Survey of Minnesota, N. H. WincHeti: Final Report of the Pennsylvania Geological Survey, LEs- LEY: Arkansas Geological Survey: Geological’Map of Baltimore and its Vicin- ity: Devonian Fishes of Canada, A. 8. Woopwarn, 73.—Nepheline Rocks in Brazil, O. A. Drrsy: Panama Geology, M. Douvitté: Geological Map of Scot- land, ‘A. GEIKIE: Quaternary Carnivores found on the island of Malta: Excava- aC tion by Glaciers: Chamberlin on the Glacial period, 74.—Mikroskopische Physiographie der petrographisch wichtigen Mineralien, von BH. ROSENBUSCH: Gesteine de Hcuatonanische West Cordillere, M. BrLowsKy: Chemical Contri- butions to the Geology of Canada, G. C. HOFFMANN, 75.—Presence of Magne-— tite in certain Minerals and Rocks, LivERSIDGE: Manual ‘of Qualitative ey pipe Analysis and Determinative Mineralogy, F. M. ENpLICcH, 76. Miscellaneous Scientific Intelligence—Geminid Meteors of Dee. 11, 1892: La Planéte Mars et ses Conditions d’Habitabilité, Cammize FLAMMARION, 77.—Investiga- — tion of the Coral Reefs of the West Indies, A. AGAssiz: Gelatine slides for | lanterh projection, W. J. WagGener: Transactions of the Texas Academy of Science: Die Klassiker der exakien MS ea selesten W.. OSTWALD, me) Society of London, 79. Obtiuary—JouNn STRONG NEWBERRY, 79.—SIR RICHARD Owey, 80. Chas. D. Walcott, U.S. Geol. Survey. “PEBRU ARY, "1893." _ Established by BENJAMIN SILLIMAN in 1818. eps ci THE AMERICAN ; EDITORS | ae JAMES D. anp EDWARD 8. DANA. ds ee ASSOCIATE EDITORS PRowessors JOSIAH iba COOKE, GEORGE L. GOODALE AND JOHN TROWBRIDGE, oF CAMBRIDGE. _Prorussors H. A. NEWTON anv-A. E. VERRILL, or es New Haven, - Prorussor GEORGE F. BARKER, or Parapevpura. THIR D SERIES. VOL XLV.[WHOLE NUMBER, CXLY. i ay 266.—FEBRUARY, 1893. WITH PLATE VI. NEW HAVEN, CONN.: J. D. & E. S. DANA. 18938. Gs TUTTLE, MOREHOUSE & TAYLOR, PRINTERS, 371 STATE STREET. lished monthly. Six dollars per year (postage prepaid). $6.40 to foreign sub- of countries in the Postal Union. Remittances should be made either by Tagistered letters, or bank checks. an A. E. FOOTE, & 4116 Elm Avenue, | Philadelphia, Pa., ( "MINERALS. Penfieldite, $1.00 to $5. 00. Fiedlerite, ce 00 to $3.00. Domeykite from Mexico, $2.00 to $10.00. Canon Diablo Meteoric Iron. The recent investigations of Prof. Fried prove conclusively that every fragment of this iron contains Diamonds capable « scratching corundum, Small, complete masses, 25c. JOREO Large mass several hundred pounds from $400. 00 upward. ~ Millerite in fine crystals, 25c. to $5.00. Chondrodite in ae crystals, $ to $3.00, from Sweden. Ulimanites from Sardinia, crystals and groups from 10e. to $5. 00. Fine large yellow Barites, Calcites and Fluors of many for and colors from England, just unpacked. A new lot of fine Pseudoleucites from: Magnet Cove, just received, 15c. to $1.50. fs Catalogue of Minerals, 125 pp. Ulustrated. Light paper ed. free to customers and those writing on headed paper. Heavy paper ed., 10c.; bound in cloth, 15 EXTRA RARE AND VALUABLE BOOKS. | Catalogues of Books, Pamphlets, ete., on any Scientific and Medical aren fee - Mention the subject you are interested i in. Agassiz. Contributions to Nat. History of U. S. 4 yols., 77 plates, 4to, DH Sd 67 pyar np st Sety Setanta cies an nS ae Re een, Reo Neer. Ce Se - Agassiz. Revision of Kchini. Parts 1 and .2, 49 plates, 4to, 1872... peBalch: Mines, Htc: of Wit ESS 2. se is aS 7s ee oer Tiere Binney & Bland. Terrestrial Air-Breathing Mollusks of N. A. 5 vols. Lee Boyle, Robert. Works and Life of. 5 vols., folio 1744, fine copy_--- Mai. ¥Gavallo:« Mlectricitys W182. 5. j425 2 2h ee ee 2 er Chenu. LEncyclopedie d’ Histoire Naturalle. 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X.—IJsothermals, Isopiestics and Isometrics relative to Viscosity ;* by C. Barus. 1. Historical.—In the following paragraphs, I endeavor to give a preliminary account of what may be called the isother- mals, the isopiestics, and the isometrics with respect to vis- cosity. Notwithstanding the great geological importancet of these relations, nobody has as yet attempted to represent them systematically. 2. The Material chosen.—In order to obtain pronounced results for the effect of pressure on viscosity, substances must be selected on which temperature has a similarly obvious effect. For, in addition to the direct access to the molecule which is beyond the reach of pressure, temperature has the same marked influence on the expansion mechanism per unit of volume increment as the other agency. Hence liquids like marine glue, pitch, ete., which change continuously from solid to liquid,-and in which this change takes place at an enor- mously rapid rate and is complete within relatively few degrees, are especially available for the present investigation. The following data refer to marine glue. Viscosity is con- sidered as a physical quality, and apart from such chemical considerations as are introduced in passing from one body to another. I must state, however, that the marine glue can be made to change its viscosity permanently, by cautiously heat- ing it for different lengths of time. Thus I obtained charges * Enlarged from a note in the Proc. American Acad., January, 1892. + As has been indicated by Mr. Clarence King, in this Journal for January. Am. Joun. Sc1.—Ts1rp Series, Vou. XLV, No. 266.—FEBRUARY, 1893. 7 88 O. Barus—LILsothermals, Isopiestics and in which, at the same temperature and pressure, the larger vis- cosities were three or even five times as high as the smaller viscosities, and my work is therefore to this extent independ- ent of the material operated on. Finally marine glue has the advantage of being both adhesive and tenacious, and errors ve to slipping ($ 5) are thus reduced as much as possible. Definitions—In my paper* on the absolute viscosity of the three states of ageregation, I defined a fluid (liquid or gas) as a body which, under constant conditions of pressure, tem- perature, and str ess, shows constant viscosity as to time. Ina solid ceteris paribus, viscosity markedly increases with the time during which stress is brought to bear. The molecular instabilities of a liquid, therefore, are supplied at the same rate in which they are used in promoting viscous motion. Ina solid they are used more rapidly than the small rate of continu- ous supply. The point of essential concern in these definitions is the con- stancy of stress, and its value below a certain critical datum. For instance, if in a solid stress be éncrcased at the (small) rate necessary to insure a constant supply of instabilities, then solid viscosity will also be constant, and I am by no means sure that in such a caset yield points would eventually present themselves as breaks in the continuity of the solid flow. On the other hand stress may be conceived to increase so fast, that even a liquid fails to present sufficient instabilities for truly viscous motion. The elasticity and brittleness of many viscous liquids, especially at low temperatures, is a case in point. 4. Hardness.—Throughout my work on viscosity,t I have adverted to the association of viscosity with zero forces acting for infinite times, and of hardness with infinite forces (relatively) acting for zero times, and have adduced many new examples showing the distinctiveness of these two properties. The subject of hardness has, however, recently taken more definite shape in the researches of Auerbach,§ based on a principle due to Hertz.|| According to these observers, hardness is an ex- pression for the elastic limits of a body in ease of contact between its plane surface and the curved surface of some other (harder) body. Hardness so defined admits of absolute measure- ment in terms of dynes per square centimeter. 5. Method of Work.—In all experiments like the present, one cannot be too careful to preconsider the conditions under * Phil. Mag., V, vol. xxix, p. 337, 1890. Cf. p. 354. + Cf. this Journal, ITI, vol xxxiv, p. 19, 1887. ¢ Phil. Mag., V, vol. xxvi, p. 210, 1888. Cf. Bull. U. 8. Geolog. Survey, No. 73, pp. 42-44, 97, 98. 1891. See § 6 below. § Auerbach, Wied. Ann., vol. xliii, p. 61, 1891. | Hertz, Crelle’s Journal, vol. xevi, p. 156, 1882. TIsometrics relative to Viscosity. 89 which the results are obtained; for one is only too apt to at- tribute an absence of flow to the effect of pressure on viscosity, when the real cause is to be found in the geometry of the apparatus employed. I have therefore availed myself of transpiration methods, since the theory of the experi- ments is in this case very fully given. The marine glue, $2, was forced out of a sufficiently large reservoir, through tubes of steel about 10™ long, and 0°5 to 1™ in diameter, cf. figure 1. Pressures as high as 2,000 atm. were applied at the reservoir, by aid of my screw com- pressor.* ‘Temperatures between 10° and 30° were kept constant by a suitable water bath. Through- out the work the flow was so ex- cessively slow (amounting to an advance of only a few millimeters per hour), that Poiseuille’s law was at once applicable. The only con- siderable source of error in the work is the occurrence of more or less incidental slipping. However, inasmuch as the outflow of marine glue is capped by a rounded sur- face, it follows that the flow is a lary i een te most marked at the axis of the the high pressure transpiration appa- tube compatibly with the theory of ratus. Scale }, Z, steel reservoir; D, the experiment. Methods of charg- steel transpiration tube; C, charge; ing, manipulation, ote., must here A wowble sods: dcomurased be omitted. ¥ 6. Volume Viscosity.—At the end of stated intervals of time (usually hours), the smal] cylinders of marine glue which had exuded were cut-off in the plane of the top of the tube with a sharp knife, and weighed. Now it was curious to note that these cylinders, left to themselves for about a day, showed a gradual and marked deformation, such that the originally plane bottom or surface of section eventually expanded into a symmetrical projecting conoid, with an acute apex angle of less than 45°. Itake this to be an example of volume viscosity, inasmuch as an expansion gradually increasing at a retarded * Phil. Mag., V, xxx, p. 338, 1890. 90 C. Barus—Lsothermals, Isopiestics and rate in the lapse of time, is the chief feature. The case, how- ever, is much more complex, for the restitution of volume is greatest in the axis of cylinder where the flow is a maximum, and it is accompanied by a series of distortions of the kind given in figure 2. Here G shows the shape of the cylinder or button immediately after cutting it off of the column A, surrounded by the steel transpiration tube. After 24 hours, when both were left free from pres- N aN ge sure, G passed into the form JZ, and G H into K. The emergence of the M cone begins visibly, soon after eut- H N a ting. After long waiting, a cavity sometimes dimples the top of the peas ANA aa Eine button as shown at Z. Ihave also Beene Te eeienenons doe obtained cup-shaped deformations, mations of exuded cylinders of the like M. The height of the project- charge C, Fig. 1, external pressure ing cone bears no obvious relation being zero. to the length of the cylinder. Thus on flat buttons 6° in diameter and less than -4™ high, the apices of the conoids will often be at a distance of -3™ and ‘-4™ from the geometric base. In general, therefore, the originally plane right sections of the transpiring column tend to become plane after stress ceases ; or plane right sections of the axially stressed column, tend to bulge out conoidally, symmetrically around the axis, and ina direction opposite to that of the stress, when stress ceases. Thus the experiment points out in a beautiful way how much residual viscosity resembles a slowly reacting elasticity.* Com- plete restitution of form cannot occur because of the dissipa- tion of energy. 7. Viscosity and Pressure.—Inasmuch as marine glue is a noneconductor and highly viscous, much time must be allowed before temperature and pressure can be assumed to have pene- trated the mass uniformly. Again whenever the oil of the compressor accidentally reaches the transpiration tube, the slip error is enormously increased and the results are worthless. A single charge will not therefore outlast many experiments. These are the chief reasons w hy much time has to be spent on the work and why it is difficult to codrdinate the results. Another annoyance is the unavoidable lack of homogeneity of the charge, and the possibility of a reservoir correction. It will therefore be expedient to briefly indicate the method by which trustworthy results were eventually reached. * A suggestive example of the gradual passage of true elasticity into true viscosity is given by the phenomena observed on stretching a string of (dry) vulcanized india rubber deposited from solution. Jf the string be suddenly re- leased. elasticity and viscosity appear as the two extreme phases of contraction, terminating a continuous series of intermediate phases. TIsometrics relative to Viscosity. 91 Table I gives an example of my earlier results. The trans- piration tubes were smooth internally as shown in figure 1. The table is one of double entry, and the data contained show the absolute viscosity (7) of marine glue at the stated temperatures and pressures, in terms of one billion g/cs units. The pressure excess is the difference of pressures at the two ends of the tube. Taste I.—Mean Values of 7/10° for Marine Glue. Ap = Pressure Excess 100atm. 300atm. 1000atm. 1500atm. 2000 atm. Temperature = 85° Se eee 3 OLO00Ks a tlh2c0=2 )s>6,0,000 OS = 138 (2°5) ee 8°30 12-0 15:2 i =) DO ane NE Soe te 2 Abape Dod ss == SOW? 065 073 ays Ayako pee Rates at SEs 2.2°5° Om? xX An/Ap = 701387 "00220 0= Ail <4 = HOE 020 In constructing the rate of change of viscosity with pres- sure, I assumed that the whole thread transpired at the mean of the pressures at the two ends of the steel tube ; or since the pressure at the open end is ZENO, at half the pressure excess. Furthermore, that Np = 1,(1 + bp) = 9,(1 +3647) If therefore Ay be the increment of viscosity corresponding to the pressure Ap, the final data of Table I (rates) are at once intelligible. What is chiefly striking in this table is the preponderating influence of temperature. Thus the material, which between 20° and 30° ©. transpires readily enough, is at 8° so nearly solid, that a burden of 2000 atmospheres, brought to bear at one end of a transpiration tube 10% long and as wide as 1°, is unable to produce perceptible flow even after 5 hours. It also appears that 7m proportion as the viscosity of a body in- creases with fall of temperature, its isothermal rate of merease with pressure also increases. Some time after, I repeated this work with great care and obtained— Temperature = lg) “20° Zoe "24° ; fy 2-7 “94 ; 71,10 = ae ' 4:3 ioe 28 : ey 8-0 3-9 ) bx 10 = art 1:3 1:8 | 4°8 it would be premature to speculate on the nature of the relation of viscosity to pressure and to temperature, on the basis of these results. As to the pressure coefticient 6, one 92 C. Barus—LIsothermals, Lsopiestics and ean only infer that its value is of the order of :005, and that it bears no obvious relation to the initial viscosity, or to tem- perature. In endeavoring to improve upon this work I cut a serew thread in the enszde of the transpiration tube and thus largely obviated slipping, by compelling the charge to flow on itself. I also made all observations in triplets, including each measure- ment at a high pressure or temperature between two fiducial measurements at a given lower pressure or temperature. Only such observations were taken for which the fiducial data were identical. Finally by treating the charges individually, I found that although the viscosities at the same temperature were very different, the pressure coefficients followed each other in the order of the initial viscosities. Experiments made in this way showed — Pemperature:== "16:59 913597 9 180 lo rl SM 7, /10° = § 50 2:15 72:50. -70> 3-4 83 ceameea O10" = 4°2 4°5 8°9 5°35 46 4°83 6°5 These are the best results I have been able to obtain. How nearly linear the variation of viscosity with pressure is, may be seen in the following example of consecutive measure- ments : Pressure excess 4p = 340 700 1055 1410 1770 3840 atm. Wascosity, 77/107) 0%" 587" 1207 60) 2:07 025300 Crm mmaies Even in case of high viscosity (>10"), a tendency of vis- cosity to increase at an accelerated rate with pressure is only vaguely apparent, e. g., Pressure excess, Ip = 505 1020 505 1540 1022 1540 atm. Miscosity, 7/10%))) == 1841 12°69 17:9) 2-0 il yialeoues Taking the above work as a whole, therefore, | am bound to infer that within the range of observation (2000 atm.), the pressure coefficient is constant: for though varying between 004 and -009, it shows no discernable relation to the initial viscosity (7, for dp = 0), or to temperature. In other words, to assume that the rate at which viscosity increases with pres- sure at any temperature, is proportional to the initial viscosity at that temperature, is the nearest approach to the actual state of the case which my observations enable me to make. Tak- ing the mean of all values in hand I thus obtain— No . = 19 g(t + 70057 p) (1) where the subscripts show the temperature (@) and pressure (7) at which viscosity (7) is taken; and where p is the mean of the pressures at the two ends of the transpiration tube. LIsometrics relative to Viscosity. 93 8. Viscosity and Temperature.—It is next in place to find a suitable expression for the relation of viscosity to tempera- ture. Contrary to my expectations this was comparatively easy; and the reason seems to be that so long as pressure is constant, the error due to slipping is less liable to change. An example of the results worked out from triads as above, and obtained with screw tubes is given in the following tables. Ap = 505 atm. Observed. Computed. Observed. Computed. Temperature 7/109 7/10? Temperature 7/10° 7/10° WHS 7°70 WES FA i8 95 toe 8:15 Salis A= 233 8b 14° 3/65) 3°61 13 GY Wee 3°82 3,80 Reo alllOD 16° 161 1°67 To Sex loM Wey 1°72 Lee Sip 24 O22 Bi “81 83 Bs “42 cae) It is seen at once that within the range of observation (12° 16° C., 15° to 23° C.) temperatures increase in arithmetical progression while viscosities decrease in. geometrical progres- sion. Hence (2) log is log Ip, » 28, and the factor B has the large value, 165. Of the two sets of data given, the initial viscosity, 7,9 is fully three times larger in one case than in the other. Nevertheless the quantity B is practically the same in both. For this reason I shirked the great labor attending experiments at higher pressures and concluded con- formably with the suggestions of the preceding paragraph, that as a first approximation the rate at which viscosity in- creases with temperature at the temperature 0°, is proportional to the viscosity at 6°, and is independent of pressure. 9. Summary and chart.—With the principle thus laid down I am able to give a graphic exhibit of the isothermals and the isopiestics. This is done in the chart, figure 3, where the ordinates are absolute viscosities, and the abscissas, pressures and temperatures respectively. The isopiestic for p = 250 atm. is directly observed between 15° and 23°. The other curves are computed from this by aid of the coefficients deduced in §$ 7, 8. The range asa whole may be taken as that of the present experiments. The (computed) initial viscosity 7,» (for p = 0 and @ = 0) is very nearly 10”. As usual p = Ap/2. 10. Lsometrics.—From these data the isometrics may be constructed graphically and in this way the curves marked 7 were obtained. I am now able to answer some important questions as to how temperature and pressure must vary, in order that viscosity may remain constant. Equations (1) and (2) lead easily to (dp/d0) = (In 10) B(1 + bp) / 6 (3) Hence the isometries are all identical as to contour and ob- 94 C. Barus—Lsothermals, Lsopiestics and tained by dropping the initial curve over stated amounts. For any viscosity and at any temperature within the range of observation, therefore, the Increment of pressure which will just annul the decrement of viscosity due to a rise of tempera- | ture of one degree Centigrade is, for instance, | 6-77 ° ry 15 KS ae | 4 y-10° B | y =3X10" i ve | 15x10” -7X10° \ foe lege M=11x10? ive} (e2) | 15x10” (as) O 1 4 E 6 Fig. 3. Fig. 3.—Chart showing the isothermals (@), the isopiestics (p), and the iso- metrics (7), relative to the viscosity of marine glue. Abscissas: Pressure in hundreds of atmospheres, or in two hundreds of atmo- spheres of pressure excess. Temperatures in degrees Centigrade beginning with 10° C. Ordinates ; Viscosities in billions of absolute (g/cs) units. Temperatures in degrees Centigrade beginning with 10° C. Isometrics relative to Viscosity. 95 Pressure = Oatm. 500atm. 1000 atm. Increment of pressure = 67 atm. 256 atm. 380 atm. and so on. Thus the relative inefficiency of pressure as com- pared with temperature is apparent, though to make the com- parison just, both agencies should be taken per unit of volume increment. Cf. § 11. 11. Digression, Logari the error due to slipping increases with pressure, i. e. in pro- portion as the charge becomes more solid, and noting the tendency (§ 7) of isothermals for high viscosity to slope up- ward, I thought it worth while to compute the isothermals on the supposition that log 7 = a'+6'p, as an extreme case. Nec- essarily, marked violence is thus done to the observations, and b’ obtained from high pressures must be smaller than 0’ from low pressures. Preferring the latter, I found, for instance = 60 Bo = aay 2:08) ieee 4 O10? == mol 73 93 73 74 As before a dependence of 0’ on 7, does not appear and 6’ = ‘00078 may be taken as the mean value. The interest which attaches to this case is its bearing on the pee which now appear as straight lines. For if = = Moyles» log C+ BO = b'p, and (dp/dé) = B/b' = 210 In other words 210 atm. would annul tle decrement of viscos- ity produced by a rise of temperature of 1° C., at all temper- atures and pressures. Seeing that in an elegant research of Ramsay and Young,* and in high pressure workt of my own, the volume isometries of liquids appear as straight lines, the present considerations may possibly claim more than passing comment. The immediate object of the present paragraph, however, is to give warrant to the statement, that in high pressure phe- nomena at least 200 atm. must be allowed per degree Centi- grade, in order that there may be no change of viscosity. 12. Maawell’s theory.~lf for the sake of definiteness, vis- cosity (7) be defined as proportional to the ratio (VW—n)/n, of the number of stable configurations (V—n), to the number of unstable configurations (7), in a given volume, then the above expressions may easily be translated into the language of Maxwell’s theory of viscosity.t I shall therefore withhold further remarks here. The conditions are simplified since for * Ramsay and Young: Phil. Mag., xxiii, p. 435, 1887; xxiv, p. 196, 1887. + Barus: Phil. Mag., xxx, p. 338, 1890. { This was done iu my note in this Journal for September, p. 255.—In the series, atom, molecule, viscous configuration, the last can vot be as sharply defined as the other two, and only the former as yet admits of generic classifica- tion (periodic law). Cf Am. Chem. Journ, xiv, pp. 197-201. 96 C. Barus—Isothermals, ete., relative to Viscosity. a substance like marine glue, 2 is probably small as compared with JV. 13. Measurement of eacessively high pressure.—Let there be given a tube of length / and radius o. Let 7 = 7,(1+p) be the viscosity of the viscous liquid forced through it by the pressure excess Jp = 2p (so that there is no pressure at one end of the tube), and at the constant temperature 6. The length (A) of a cylinder of fluid issuing per unit of time () will then be p’Ap/8/7,(1+bAp/2). Hence if negative pressures be excluded, the function 4/¢ is of a kind which continually increases with dp, a state of the case which would not be true if the expression of $11 were applicable. In view of the observed property of A/¢, it is worth inquir- ing in how far the transpiration method is available for high pressure measurement, when most other means fail. Take for example a tube ;, inch in diameter and 1 inch long. Then the mass m of the above marine glue which at say 18° would exude per hour is TD MO? = DOO) 5x0 7810 7900 7950 grams. Ap = 1000 5000 10000 15000 20000 atm. - where 7 = 10° 1+-00285Ap). Thus it appears that whereas a hole = inch in diameter may be efficiently sealed by marine glue at 18° C., pressure meas- urement by aid of the exuding mass is impossible above 10,000 atm., whereas even between 5000 atm. and 10,000 atm. the method is insensitive. To use a method like the present - for very high pressure measurement, a substance of smaller pressure coefficient must therefore be sought, if such a one with other necessary qualities, exists. It is with the object of searching for such a body, as well as of finding the maximum of hydrostatic pressure attainable in the laboratory that Thad a tinned screw and socket constructed,* and hope to be able to report the results of my work at an early opportunity. To my knowledge the only other gauge available under the eir- cumstances is the one I based on the resistance of mercury. It is sufficient, however, for making the comparisons in ques- tion. Phys. Lab. U.S. Geolog. Survey, Washington, D. C. * Proceed. American Acad., xxv, pp. 94, 108, 1890. G. F. Becker—‘* Potential” a Bernoullian Term. 97 Art. XI.—“ Potential” a Bernoullian Term; by Gro. F. Becker. PorENTIAL as the name of a function was undoubtedly introduced by Gauss in 1840. He wrote: “Zur bequemern Handhabung der dazu dienenden Untersuchungen werden wir uns erlauben dieses V mit einer besondern Benennung zu belegen, und die Grésse das Potential der Massen, worauf sie sich bezieht, nennen.”* But Gauss was certainly not the first to employ the corresponding adjective in a similar sense. George Green employed the term potential function in 1828 in his famous paper on electricity and magnetism. He intro- duced the phrase by remarking that certain memoirs of Poisson’s “are in fact founded upon the consideration of what have, in this essay, been termed potential functions.’+ In section 1 of the paper he says: “As this function .. . will occur very frequently in what follows, we have ventured to eall it the potential function belonging to the system.” No- where in this paper can I find the word potential used as a noun, while ‘‘ potential function” is met with on almost every page. Most physicists give Gauss full credit for independent in- vestigation of the potential, but Todhunter refers to the matter in a manner which would seem to convey an innuendo. ‘‘ We may observe,” he says, “that the name Potential was first used by the late George Green. . . . Gauss used the word in his memoir . . . published in 1840. As Gauss does not refer to any previous authority we are, I presume, to infer that he had independently selected the name.”{ As was pointed out above, this is not a correct statement, since Green did not use the name potential but only the adjective; and the effect of the words “I presume” is to suggest a doubt whether Gauss might not have been acquainted with Green’s nomenclature, and consequently also with the theory portions of which he is credited with rediscovering. Gauss however never displayed any tendency to plagiarism. It is not very generally known, though it has been men- tioned in modern literature, that Daniel Bernoulli and Euler employed the term vis potentialis. A single passage from Euler will illustrate its use: “ Quamobrem cum vir celeberri- * Alloemeine Lehrsatze in Bez. auf... Anziehungs- u. Abstossungs-Krafte. Collected works, vol. v, 1867, p. 200. + Reprinted in Crelle’s Journal, vol. xxxix, p. 77, 1850, and in his collected papers. ¢ Math. hist. theories of attraction and the figure of the earth, vol. ii, 1873, p- 26. 98 G. F. Becker—< Potential” a Bernoullian Term. mus... Daniel Bernoulli mihi indicasset se universam vim, quae in lamina elastica ineurvata insit, una quadam formula quam vim potentialem appellat complecti posse, haneque ex- pressionem in curva elastica minimam esse oportere, ete.” In stating his problem he says again “atque, secundum Bernoul- lium, exprimetur vs potentialis in laminae portione AM eon- tenta hae formula af = ,»’ s being the are of the spring and 2 yy RY, the radius of curvature.* It is evident that in these passages vis is used in the same sense as in vis viva and that it is to be translated energy, so that Bernoulli’s proposition was that the elastic curve must be such as to make something which he regarded as the potential energy of a bent spring a minimum. Todhunter in his History of Elasticity, 1886, quotes pas- sages from D. Bernoulli’s letters in 1742-3, in which the vis potentialis i is mentioned ; but since the historian makes no allu- sion to his earlier remarks on the origin of the name Potential, it must be inferred that no relation between the two terms suggested itself to him. Had Todhunter lived to edit his history, perhaps this omission would have been supplied. It is well known that Green’s great memoir was not pub- lished in the ordinary manner, but by subscription in Notting- ham, and that it attracted no attention for many years either in Great Britain or on the Continent. Gauss was thus very naturally ignorant of it. On the other hand it is substantially impossible to suppose Gauss ignorant of the famous memoir of Kuler quoted above. The methods there developed of finding curves have been superseded by those of the calculus of varia- tions; but the appendix, Additamentum de curvis elasticrs, from which the passage quoted above is taken, contains the classification of elastic curves into nine species which, so far as I am aware, has received no addition or improvement. There can thus be substantially no doubt that Daniel Bernoulli’s vis potentialis suggested to Gauss the name poten- tial for a somewhat similar but more general function. Either he considered the change of form of the expression and the increased generality of its significance as sufficient to make any reference to Bernoulli needless; or, as seems more prob- able, he assumed that his readers were as well read as himself and that an allusion was superfluous.+ * De Methodis inveniendi lineas curvas maximi minimive proprietate gaudentes. 1744, pp. 246, 247. + The potential has received a variety of names in modern times. “ Force function,” which seems to be used by European mathematicians at least as fre- quently as potential. was proposed by W. R. Hamilton in his famous memoir on varying action, Phil. Trans, 1834, p. 249. In the same year B. de Saint-Venant called it ‘latent dynamic capital” (Lecons de Navier, 1861, p. 786) and Ampére suggested ‘‘ implicit vis viva.” Ann. chim. phys., vol. lvili, 1835, p. 438. G. F. Becker—‘ Potential” a Bernoullian Term. 99 It is natural to inquire what Euler and Bernoulli meant in terms of modern nomenclature by vis potentialis. Now Saint- Venant has pointed out®* that if J/ is Young’s modulus and J the moment of inertia of the cross section of the spring, the work done in flexure for a length s is MI fds R? so that Bernoulli’s function is simply proportional to the potential energy as that expression is now understood and to the Potential, a fact to which the great French elastician calls attention. There seems to be a general impression that the natural philosophers of the last century, when.they used the quanti- ties now known as kinetic, potential and total energy at all, regarded them from a purely algebraical or geometrical point of view, failing to perceive their great physical significance. In this respect these physicists seem to have been underrated : as some passages from the first John Bernoulli, Euler’s teacher and D. Bernoulli’s father, will show. Ina paper on the true conception of living forcest he generalizes the idea of vis viva and defines it as equivalent to capacity for doing work, or, facultas agendi, which is simply a Latin equivalent of the Greek energy. In Section I of this paper he says (trans- lated) : “Vis viva does not consist in the actual exertion, but in the capacity for doing work; for it subsists even when it does no work nor has any object whereon it could act; so for example a strained spring, or again a body in motion, has in itself the capacity of doing work, so that if nothing external to itself come in-its way upon which it may exert itself, and so long as there is no object present with which it can come in contact, it infallibly retains it all undiminished by time, and does not do the work which it would be capable of doing if it had the opportunity.” This seems a clear and even a vivid statement of the law: ‘When a system is subjected to no external forces, its energy remains constant.” In Section III he takes a further step. ‘ Vis viva (which would be more aptly named facultas agendi, gallice le pouvoir) * Lecons de Navier, edition of 1864, p. exij. + De vera notione virium vivarum, Acta Eruditorum, Leipzig, 1735, p. 210. ¢ The term power is now rarely used for energy, but it is scar cely a generation since this meaning was common enough. Saint: Venant (op. cit., p. 785) i in 1864 defined the poteutial of one or more forces as “leur pouvoir moteur total.” B. Peirce in his great work on analytical mechanics 1865 always uses ‘‘ power” instead of “energy.” 100 L. V. Pirsson—Datolite from Loughboro, Ont. is something real and substantial, which has an independent existence and, whatever it consists of, depends upon nothing else. Whence we conclude, that any given vis viva is of determinate quantity of which none can disappear except it reappear in the effect produced. Hence it follows at once, that vis viva is always preserved, and so perfectly that what inhered in one or many bodies before action is now, after action, necessarily found in another or in several others except- ing what remained in the first system. And this we eall the conservationem Vvirium vivarum.” Compare this with the modern statement: In any system the variation of energy is equal to the external work done by the system less the work done by external forces upon the system. : John Bernoulli was under no misapprehension as to the importance of the principles he had stated. He says in sub- stance: Whether bodies are regarded as communicating motion to one another or whether one considers the various modifica- tions of the motion of one and the same body depending on its own force (where nothing can vanish without an equivalent effect), ‘‘pro fundamento et principio universali poni debet conservatio virium vivarum, hoe est illius facultatis agendi.” That such men as Daniel Bernoulli and Euler should have been deaf to teachings like these is impossible and they must therefore have had an idea of the vis potentialis differing but little from that which the words convey to modern ears. It would be interesting to know whether they really omitted to show in any portion of their writings why they felt them- selves at liberty to base investigations on the statement that the potential energy of astrained solid isa minimum. Indeed it appears to me that the few notes given above are sufticient to indicate an opportunity for a physicist to write a most interesting essay on the evolution of the potential up to the date of Lagrange’s memoir on the movement of a number of mutually attracting bodies (1777) in which the potential seems to have been used for the first time in an entirely general form. Washington, December, 1892. Art. XIL.—Datolite from Loughboro, Ontario ; by L. V. Pirsson. THE crystals of datolite which are the subject of this note were sent to this laboratory for examination through the kind- ness of Messrs. English & Oo., of New York. They had been forwarded to them by the owner and the occurrence is the L. V. Pirsson—Datolite from Loughboro, Ont. 101 Lacy Mine, Loughboro, Ontario. More magnificent crystals of this species have probably never been found in America and they are equalled by few European specimens. ‘They are pure and transparent with a yellowish green tinge and enclose only a few small erystals of chalcopyrite as impurities. At first glance they resemble large topaz crystals. In size they meas- ure for the largest crystals 3xX2$}x2°%™. Nothing is known of the mode of occurrence save what can be gathered from the examination of a small amount of associated material on the hand-specimens. rom this, the mineral seems to have formed in veins in a light colored igneous rock too much acted upon by fumarole agencies for satisfactory determination, but con- taining a considerable amount of a brownish biotite. On the specimens the datolite crystals are associated with quartz, cal- cite and chalcopyrite. The material consisted of two hand specimens with groups of large crystals and one detached crystal of the size mentioned. In habit these crystals are nearly all alike in the development of their planes, being characterized by a prismatic like develop- ment in the zone of clinodomes following the orientation given this species by E. 8. Dana.* The loose crystal could be easily measured and was also the most complex in the development of its planes. The follow- ing forms were identified : a (100) i w (104) — $4 n (111) —1 b (010) 7-2 a (102) — 4-4 e(112)4 _ c (001) O E (102) 4-7 BIW) m (110) I g (012) $-2 @Q (122) — 1-2 o (120) i-3 mx (011) 1-4 Ci23) a=) This erystal is shown in the accompanying figure. All the faces except the pinacoids and clinodomes have been relatively exaggerated in size to exhibit them better. No other forms beyond these were observed on any other of the crystals. The zone 0, 8, Q, U was well developed and gave excel- lent reflections on the goniometer. The crystals were not studied op- tically as no material was available without damage to the specimens, but, as confusion has frequently occurred in the orientation of this species owing to the great similarity of angles in the zones of prisms and of clinodomes, the following table of measured and calculated angles is appended to show the cor- rectness of the orientation and the identification of the forms. * System of Mineralogy, New York, 1892, p. 502 et seq. 102 G. H. Williams— Rock-cutting Machine. The calculated angles are those from Dauber’s* measure- ments from which. we have the elements, @:6:¢ = 063446: 1:1°26574 aug. 6 = 89° 51’ 20" Calc. Meas. CA 001 .~ 100 89 514 89° 36’ aam 100 ~ 110 32 234 32 264 32 264 Mx A Mx O11, 011 76 37 16 37 ann MOO Zs Mat 38 55 38 52 38 53 aa Mx 1004 011 89 55 89 50 CAN OOLALIL 66 57 66 49 QGx2 100 ~. 102 45 04 44 52 aau 100 ~. 104 63 224 63 16 Q@aé 100, 102 45 08% 45 12 CAG 001 4 012 32 19% Be MG) ow, Be Wak 32 08 CA Mx 001 A O11 51 414 51 414 511935 BAG V2 sag 48 194 48 21 aao 100 . 120 51 454 52. 19 and 100 ~ 122 58 12 58 10 an U 100 ~. 123 62 58 62 54 an ZB 1004 121 53 434 53 41 53 42 cap 001,121 72 41 TS BS} ca Q 001 4 122 57 584 57 59 Bir (Of 001 4123 47 04 46 54 Probably the largest European erystals of datolite are those from Baveno, Italy. One of these described by Sellat is mentioned by Brusht as being 4°5 x 3°75 x 1°5 inches. Laboratory of Mineralogy and Petrography, Sheffield Scientific School, Oct., 1892. Art. XIII.—A New Machine for Cutting and Grinding thin sections of Rocks and Minerals; by GrorcE H. WILLIAMS. A BRIEF description of a new machine for cutting and erinding rock sections in which electricity furnishes an eco- nomical and satisfactory motive power, may prove acceptable to the constantly increasing number of workers in mineralogy and petrography. This machine was devised for the petro- graphical laboratory of the Johns Hopkins University pver a year ago, and since then it has been in more or less constant use. It has thoroughly established its reputation for accurate and rapid work, while experience has suggested some improve- ments on the original model. * Pogo. Ann., 103, 116, 1858. + Wien. Akad. Berichte, xxix, 239. ¢ VIII Supp. Dana’s Min. This Journ., May, 1860, vol. xxix, 2d series. G. H. Williams—Rock-cutting Machine. 108 The accompanying cut of the machine (fig. 1) hardly needs any explanation. It is seen to consist of a substantial table, carrying in its lower part the electric batteries and motor iowa: while upon its upper surface is placed the apparatus for grinding and sawing. The table is approximately three and one-half feet square and two feet nine inches high. It is constructed with all of its appurtenances by the Donaldson-Macrae Electric Com- pany of 215 N. Calvert St., Baltimore, whose storage batteries and electric motors are well known. The price of the ma- chine complete is $130.00, consisting of the following parts: 1. Three two hundred ampere-hour storage batteries, 13 inches high, in portabie rubber cases. These batteries stand Am. Jour. Sci1.—Turrp Series, VoL. XLV, No. 266.—FEBRUARY, 1893. 8 104 G. H. Williams—Rock-cutting Machine. on a firmly constructed cross-piece from which they may be readily removed for recharging. 2. One one-eighth horse power electric motor of the Donald- son-Macrae pattern (fig. 2). This is fastened to a second A cross-piece above the bat- teries and below the table surface. It is provided with two pulleys from al! which belts pass to the ONG Loe shafts on the table, which = (G carry the grinding disks and diamond saw. 3. The grinding appa- ratus consists of two cir- cular disks of solid copper, 9 inches in diameter and Hee 2 inch thick, which may be used alternately as different grades of emery are required. They are attached either by a screw or square socket to a ver- tical iron spindle which revolves smoothly in a conical bearing. The grinding disk is surrounded when in use by a large cylin- drical pan of tin (not shown in the cut) which has an opening in its center to allow of the passage of the spindle. 4. The sawing apparatus consists of a horizontal counter- shaft, placed on a different part of the table from the grinding disk, and connected with the motor by a separate belt. It carries at one end a vertical wheel of solid emery, and at the other an attachment, level-table and guide for the diamond- saw.* A small water-can and spout (not shown in the cut) is suspended over the level-table to keep the edge of the saw wet when it is in use. Under some circumstances it may be found advantageous to obtain electricity for this motor by a direct wire from an elec- tric light or power company. Considerable inquiry has shown, however, that in Baltimore the storage batteries are more convenient, safe and economical. A single charging lasts the needs of a laboratory of ten students for a month: The batteries are removed by the electric company and returned with little or no delay at a cost of $3.75 for recharging. Petrographical Laboratory, Johns Hopkins University, Dec. 10, 1892. Cra @ S A pS * Admirable saws, circular tin disks 8 inches in diameter with one inch center aperture whose edge is provided with diamond dust secured by cement, may be had of Wm. Kerr, No. 292 Westminster St., Providence, R. I., for $12.00 per half dozen. W. P. Headden—Stannite, ete. 105 Art. XIV.—Stannite and some of its Alteration Products from the Black Hills, S. D.; by WM. P. HEADDEN. SEVERAL years ago Mr. Fred. J. Cross found at the Peerless Mine, which is located about one-half mile northeast of the Etta Mine post office, and was then being worked for mica, a piece of some mineral imbedded in the pellucid quartz of the locality which he did not recognize as having seen before either from this or any other locality i in the Hills. This mate- rial which he kindly gave me forms the subject of this investi- gation. One piece was all that Mr. Cross found at the time and, though he has subsequently sought for it diligently, he has been unable to find more of it, and I have been entirely unsuccessful in my search for it; therefore the description of the occurrence of this mineral in the black Hills must be con- fined to the description of this one specimen with such excep- tion as will be mentioned hereafter. The exterior of the mass is earthy in texture and from dirty green to brownish yellow in color. The texture and color change rapidly the former becoming in the interior firm, almost massive, with uneven to subconchoidal fracture, while the color passes through a pure copper-green to greenish black. The appearance of the mass leaves no doubt but that it is what remains of an original mass now in an advanced stage of alteration. This is plain to the naked eye, but is best seen under a good pocket magnifier. The texture of the mass varies, even in those portions which are earthy, and where the alteration is most complete there are portions varying in size from mere points to particles as large as small shot which have a vitreous luster, a green color, and an uneven fracture which is rather difficult to observe. A closer study of these spots shows that they, like the mass itself, are filled with seams and are only remnants of an unrecognized decomposition product. While these particles are readily distinguishable from the enveloping mass, they are so permeated by seams filled with — other material, probably identical with the mass itself, that no mechanical separation of the two would be possible. The dull earthy substance becomes less abundant in the interior but is nowhere absent. The portion having a copper-green color is similar to the lustrous spots of the other portion and the two are probably identical. The former like the latter is traversed by a fine network of seams whose centers are filled with a substance appearing to be almost white when viewed with a rather strong magnifier. This is particularly easily observed in the larger 106 Wee: Headden—Stannite and some of its seams; but this substance which is one of the end produets of the alteration, an impure oxide of tin, can be traced as minute threads running through the mass in every direction even into its deeper portions where small portions of the original stan- nite still remain. The meshes of this reticulation are sometimes filled with an apparently homogeneous mass of a varying green color and strong vitreous luster, but this is rather exceptional. The rule is that they are filled with material which varies macroscopi- cally and probably chemically; as some of the patches are white while others are different shades of blue or green. The firmer portion of the mass is really not uniform in color, green and grayish black portions being intimately mingled, producing a greenish black. The stannite frequently shows a bronzy tarnish which makes the mixed nature of the mass apparent. The luster of this mass on a fresh fracture surface is metallic, its streak and powder are green and it yields three products when treated with hydric chloride, i.e. a solution containing a large amount of tin and a residue made up of fragments of the remaining stannite and a yellowish white powder consisting of stannic oxide with a trace of iron. The stannite is grayish black. It tarnishes blue and bronze. Hardness 4; Sp. gr. 4534, streak black. The material used for analysis appeared to be quite pure and free from the accompanying alteration products, but both the quantity of the material and the size of the fragments forbade any further attempt to purify it by gentle rubbing or other means. The analysis yielded the following results : At. eq. Suliphursesee eee ae 28°26 88°31 AD at Cm erate tame te Peete 24 08 20°40 Copp crise ae eee e298 47°16 NG RGh a veGees een oe ears TA5 13°30 TAN ly een Tare eee ROTEL 13°40 @adimininagse ee 0°33 0°20 INNO Eee webs es UES Insolulb lets. 42. 5 eee eal 100°15 If we assume the copper to be present as cuprous and the tin as stannic sulphide, and express the atomic equivalents in terms of sulphur, we obtain : Sulphur 2a. 2 368873 1earorn 6.64 6°64 1 Tins. hes ee 40°80 3°06 | Copper 4a ame ss: 23°58 ort : ; hone ee see al S230 1:00 r GiB? 1/02 ZANE Sy See ee 13°40 1°02 J / Alteration Products from the Black Hills, S. D. 107 The ratio of the sulphur required by he tin as stannic sulphide to the total sulphur is as 1: 2°16 or 1:2 giving us the formula 2RS+S8n8, in which R= €u,, Fey, Zn+Cd,,, which agrees with the formula heretofore accepted for stannite except that a small portion of the zine in this specimen has been replaced by cadmium. I have been very explicit in describing the mass from which I obtained this portion of stannite for the reason that about four years ago I found a similar earthy material occurring in patches in the coarse-grained granite of the Etta Mine. I suc- ceeded in obtaining small quantities of this material at various times and finally enough for an analysis. The quantity actually obtained was rather more than 0°35 grm. Whether it occurs more abundantly at some point in the workings which I have failed to find, I cannot say, but I found it occurring very sparingly. The chief portion of all that I obtained on iy various visits to the locality extending over a period of two years was found scattered in small bunches through a large piece of granite which had been removed from its place and ‘carried some distance from the mine. The point at which I found it most abundant in place was in the face of an open cut on the northeast side of the hill together with cassiterite; they are intimately associated with a somewhat laminated feldspar. I have reason to believe that it was more abundant formerly than now, as I came into possession of a specimen taken from the mine, under its first management, which is much richer in this material than any specimen which I have myself been able to find or to subsequently obtain. The association of this material with the cassiterite is more inti- mate in this specimen than is usual; in only one instance have I seen it more so, namely in a piece of massive cassiterite which has a small depression partly filled with it inclosing fragments of stannite. This is interesting because the speci- men was found at the pom where this cut was opened, and establishes the identity of the Etta and Peerless material so far as their origin is concerned. An analysis of the best Etta material that I could obtain was made in 1889 and is given here for comparison with one of Peerless material which was made recently. The air-dried material had a dirty green color and gave, after deducting 9°84 per cent gangue: Atomic equivalents. jal LO) saleiesizy H :0154 15°40 14°66 29°3 30 CHOW 12:53 Cu ‘1021 1-615 1:44 2°88 3 Fe,O, 8-94 Fe -0626 1-119 1 2 2 SnO, 64:33 Sn 5061 4°289 3°83 7°66 8 SO, trace Or 3105 19°400 17°38 34°76 35 Sb,O, trace ~ ZnO trace 0°9967 99°67 _108 W. P. Headden—Stannite and some of its It is true that we can give an interpretation to the ratios obtained, but a simple and necessary relation between them is not evident. Still if we assume the iron present as xantho- siderite and the copper as cupric hydrate we obtain the follow- ing: Fe,O,2H,O, 3Cu(OH),, 58n(OH),, 88n0,. This would demand but two more atoms of oxygen than we have really found and this slight violence to the ratios found may be justifiable on the ground that these ratios are only approxi- mate. The identification of a new mineral, cuprocassiterite, has recently been announced by Mr. Titus Ulke.* The material which served for this identification was also from the Etta Mine and according to his description from the same (?) point in the mine, as no work has been done at this locality for seve- ral years, no new openings have keen made. Mr. Ulke does not give the detailed results of his analysis but states ‘“‘ Upon analysis 60 per cent Sn, 12 per cent Cu, and 8 per cent H,O were found with traces of iron and silica.” This when ealeu- lated into oxides in which form these constituents evidently existed in the material gives : At. equiv. SnO, 76°27 Sn 60:00 508 5B CuO 15:04 Cu 12°00 1°94 D HO» 48:00 Hissoness |. 6:86 9 O 26:48 16°52 16 99°31] Mr. Ulke proposes 48nO0,+Cu,Sn(OH), as the formula cor- responding to this analysis. He notices the presence of iron and silica but as the calculated analysis falls less than seven- tenths of one per cent short of one hundred there could have been no considerable quantity of either of these present. This must be an accident, for as I have stated before, the probabili- ties are strongly in favor of the material serving for the re- spective analyses being from the same spot, again there can be no doubt but that this material is an alteration product derived from stannite and it is somewhat remarkable that the iron should be so completely removed while the copper and so much of the tin remains in the form of hydrate. The vary- ing composition of this material is not only indicated by the difference in the quantity of iron present but also by the ratios of the anhydrous to the hydrous oxides. Mr. Ulkes gives 4:2,1.e. 48n0,: SOE). while my analysis gives 3: 9,1.e. 38n0O, : Fe,0,2H,0+38Cu( OH), +58n(OH), in which the cop- per is considered as cupric instead of cuprous hydrate. * Proceeding American Institute of Mining Engineers, meeting of Feb., 1892. Alteration Products from the Black Hills, S. D. 109 Having a larger quantity of similar but purer material from the Peerless I subjected a portion of it to analysis. The air- dried material loses 5-06 per cent when dried at 100° and the dried mass is so hygroscopic that it regained 4°35 per cent of its original weight when exposed to the atmosphere for forty- five minutes, and after eighteen hours its loss amounted to only a few tenths of a milligram. This material can be scratched with the finger nail; absorbs water with avidity and adheres quite strongly to the tongue and has a clayey odor and taste. I found the sp. gr. for two portions of the material 3312 and 38°374 respectively. Mr. Ulke reports specific gravity nearly 5. Analysis of material dried at 100°: Loss upon ignition. 8°20 | es Oya ie ear Fe 185 CuOe Se eee vor s 18°02 SHOe meee wee eee 46°07 } = 84°65 = Soluble in HCl AnOrCd Ome se 0°51 | SOBs eee Sale Chace SRO aes ae ew yaa es trace | Ganeuees ase JS 1°68 14°64 ~~ Insol. in HCl iSnOr(Me trace) ~ 222. 12°96 =——- 99:29 Computing the portion soluble in hydric chloride to 100, we obtain Atomic equivalents. H,O 9°68 Hl 0108) 108; 59) 11H,O Fe,O, 13°98 Be 098i Wiel Oy eZ, 2Fe,0, CuO 21°34 Cu 1704 26:96 3 | 6CuO SnO, 54°40 Set 4 2 OW 3D Ale tsb ZnO, CdO_ _°60 Zn 0048 “74 | 75nO, 100-00 ORs2883)| Pug Ops ray This gives no approximation to any simple and evident formula for the portion soluble in hydrie chloride. The solu- tion gave no reaction for ferrous oxide even after gentle boiling indicating the absence of any ferrous, stannous or other lower oxide which would reduce the ferric salt under these condi- tions, while the color of the mass and the bright blue coatings on the fracture planes in the quartz point to the absence of an anhydrous cupric oxide. That the stannic oxide insoluble in hydric chloride is present as such and ought not to be con- sidered as a part of some other combination is indicated by the macroscopic properties already detailed and even more strongly by the deportment of the material in lumps when 110 W. P. Headden—Stannite, ete. treated with hydric chloride, which removes the green, vitre- ous portion leaving a smaller or larger portion of yellowish stannic oxide, which usually preserves in some degree the form of the original network and sometimes sufficiently well, to show it plainly. I could observe no evolution of canbe di- oxide when the powdered mass, thoronghly wet with water, was treated with hydric chloride. The San Antonio tin ore as described by Professor F. A. Genth of Philadelphia* suggests the same problem presented here, but much more involved. In this article he ealls par- ticular attention to the fact that a portion of the stannic oxide amounting to 3°86 per cent of the weight of, the ore is soluble in hydric “chloride and adds that “it is difficult to perceive in which form this tin existed,” but adduces proof that it was not present as stannous oxide. It may justly be urged that my analyses of the Etta and Peerless material are not comparable because they were made by different methods. This is true only in regard to some of the data given by them, it does not change the fact that the constituents are the same but present in varying proportions and it is also probable that no material change was produced by drying at 100° as the water lost and no more was regained. Until fuller and more satisfactory data can be acquired con- cerning several points relative to this substance it can scarcely be considered as more than a mixture containing one or more hydrated compounds of copper, iron and tin related to the stannates, respectively the metastannates, which are soluble in hydric chloride but for which we cannot at the present time establish a formula. The almost complete removal of the sulphur, the green and blue stains which are without doubt largely but not wholly due to the copper, found both in the quartz of the Peerless and to a less extent in the feldspar of the Etta, suggest that some of these alteration products are soluble in water and that such salts may have furnished the solutions from which the stannic oxide forming the imitative forms described by Prof. Genth in the article referred to was deposited. This may also help to the explanation of the pseudomorphs of stannic oxide after feldspar, first observed in Cornwall by Mr. Richard Pearce now of Denver, Colo. It seems very probable that such solutions have been the source of the stannic oxide-de- posited in small irregular patches on some of the spodumene crystals found in the Etta Mine. State School of Mines, Rapid City, 8. D. * Contribution to Mineralogy, No. XX XI, 1887. Read before American Philo- sophical Society, March 18th, 1887. R. T. Hill—Hematite and Martite of Mexico. lala Art. XV.—The Occurrence of Hematite and Martite Lron Ores in Mexico ; by Rospert T. HI. THE iron ores of Mexico have been frequently mentioned, but the writer is aware of no attempt to define their position and origin. The admirable paper of Mr. John Birkinbine, the well-known mining engineer, has made known the chemi. eal composition and extent of the famed iron mountain of Durango,* and Prof. B. Silliman has described the peculiar occurrence of martite at this locality.t The writer has recently studied several deposits of similar iron ores in Mexico, and in August, 1892, gave special atten- tion to the study of certain beds situated on the line of the Mexican International railway, near the city of Monclova, in the State of Coahuila. The mountain in which the ore occurs, like the iron mountain of Durango, is known as the Sierra de Mercado, and is one of the elongated, isolated masses charac- teristic of the Great Basin region of the United States, of which the so-called Mexican plateau is a geographic continua- tion, and is surrounded by the customary basin plains, or val- leys, filled in by debris of the mountains. In structure the mountain is composed of sub-vertical strata of a hard blue and gray limestone, very much resembling the familiar Paleozoic mountain limestones of the Appalachian region, but which, in fact, as will be shown is of Mesozoic age. . Through this limestone, in a direction usually corre- sponding with the strike of its stratification are vast masses of eruptive diorite. which simulate the limestone in color. Inas- much as this diorite includes large fragments of the lime- stone in its substance there can be no doubt of its later origin. The talus which imbeds the base of the mountain, and is widely distributed over the plain, is composed principally of limestone cobble, with a large admixture of rounded lumps of iron ore, black upon the surface, strongly resembling magne- tite, but which reveal a lustrous (specular) surface structure upon fracture, and give the streak of hematite, This iron ore is so abundant in the talus that it suggests the fact that the beds from which it was originally derived have long been exposed to denudation. In ascending one of the numerous lateral cations at the south end of the mountain, many alternations of the limestone *“The Cerro de Mercado (Iron Mountain) at Durango, Mexico, by John Birkinbine,” Trans. of the Am. Inst. of Mining Engineers, 1884, pp. 1-19. + ** Martite of the Cerro Mercado, or Iron Mountain of Durango, and Certain Other Ores of Durango, by B. Silliman, this Journal, November, 1882. 112 R. T. Hill—Hematite and Martite of Mexico. and diorite are crossed, all of which strike in the direction of the axial trend of the mountain, with slight local sinuosities. At an elevation of about 1000 feet above the railway which skirts the base of the mountain, and nearly at the summit, the original source of the iron debris of the plain is found in large masses, or pseudo-veins, of ore, the bodies of which occur in a line corresponding with the strike of the limestone diorite contacts, and are principally exposed at the crests of the ridges dividing the lateral cafions. The ore bodies resem- ble fragments of a vertical vein, but apparently have no direct continuation. They occur along the line of contact between the upper limestone and the diorite, but some of the masses are entirely embedded in the limestone and others in the diorite, while several present a wall of each. The bodies could not be described as lenses, as are the masses of specular ore in either Algonkian or Archeean schist in Llano county, Texas, nor are they true beds, but apparently formed by the replacement of the limestone at the limestone-diorite contact, or replacement of the masses of limestone inclnded in the diorite. The principal outcrops, seen along a north and south line of six miles, were as follows, beginning at the south end of the mountain : 1. The first lateral ridge projecting from the east side of the north end of the mountain is crossed by the vein or bed which upon one side reveals a cross section of 30 feet and an expo sure of 250 feet parallel to the mountain crest north and south. 2. On the opposite side of the ridge apparently the same bed reappears with a vertical exposure of 50 feet. 3. In the same line of outcrop is a third exposure of apparently the same mass as No.1. 4. Northward are two outcrops with areal exposures of 6532 feet and 15030 feet respectively. 5. One-half mile north of the above is another outcrop of the ore with a surface area of 30240 feet. 6 One quarter of a mile northward is the mine known as La Paloma which has been somewhat developed; it has an areal exposure of 45 X 200 feet and a vertical face of 50 feet. 7. Still northward is an outcrop resembling No. 2 in quantity exposed. 8. Two miles north and nearest to Monclova is the last outerop visited ; it has a vertical exposure of 150 feet and a width of 30 feet at the top which rapidly diminishes downward. All of these masses, from their uniform width and con- tinuity of strike are apparently genetically connected con- tinuously along a structural parting between the diorite and limestone. The ore presents peculiar mineralogical conditions. Where the interior of the vein is exposed by blasting its mass con- sists of a bright lustrous (specular) hematite. This would not R. T. Hill— Hematite and Martite of Mexico. 113 be inferred from surface examination, however, for every- where the mass has the exterior appearance of black magnetite and has been mistaken for this ore by many observers. Close examination of the surface shows it studded with minute granules and the octahedral crystals of martite—a hematitic pseudomorph after magnetite—resembling similar phenomena with the ores of Durango and other Mexican localities de- seribed by Prof. B. Silliman.* Of the Durango ores Prof. Silliman said: “ At first sight the octahedral crystals of various sizes sug- gested only magnetite, but the magnet failed to attract the ore while the streak immediately indicated hematite.” Mr. Birkinbine also notes the resemblance of the Durango hematite to magnetite; the writer was obliged to make the magnet tests before he was satisfied that the substance was not magnetite. In view of these facts it is necessary to be cau- tious about accepting the determinations of magnetite made by casual observers in other localities. In most of the out- crops only the hematite and martite could be seen, but in several outcrops, especially the one nearest Monclova, about a foot of limonite could be seen against the hanging wall of the limestone. Prof. Persifor Frazer has mentioned the occur- rence of pyrite in the Paloma opening, and says :+ ‘* There is the clearest evidence that the iron ore is an alteration product of pyrite, but so complete has been the alteration that a few inches above the line of demarcation between the sulphide and the oxide hardly a trace of the sulphur remains.” The writer must confess that after having examined many of these iron masses, he has never seen .a trace of the pyrite beds above alluded to. In chemical composition the ore shows great resemblance to many other localities in Mexico, especially those given by Mr. Birkinbine and Prof. Silliman, as shown by comparison with the following analyses of Paloma made by Mr. Davenport Fisher of Milwaukee, from eighty pure specimens collected by Mr. H. M. Wakefield of the same city: hroniee he ee G4e83il | ae Oxide Vasu 92°61 Silicaes see 2°98 Phosphorus ~~. 018 04 AN MiAaay hehe 4°35 99°98 No sulphur, manganese, lime, magnesia or titanium were found. * Martite of the Cerro de Mercado or Iron Mountain, Durango, Mexico, and certain other Ores of Sinaloa. this Journal, Noy.. 1882. + Certain silver and iron mines in the States of Coahuila and Nuevo Leon, New Mexico,” Trans. Am. Inst. Mining Engineers, vol. xii, pp. 538-568. 114 LR. T. Hill—Hematite and Martite of Mexico. Dr. Frazer ‘‘in order to test the value of this ore severely” took a sample across the face inclosed in the pit inclusive of a horse of limestone there visible, and some scattered masses of sandy material, which gave 53°80 per cent of metallic iron.” He gives 0°61 to 4°5 of sulphur in the various analyses of this impure sampling. It is not the purpose of this paper to advance an opinion of the origin of this ore, for the writer is unable to satisfy him- self upon this subject, but the opinion of Prof. Frazer that they are altered pyrites is contrary to his observation. The limestone may be looked upon as the most probable source, however, for occurrences of smaller quantities of iron ore have been frequently reported at the contact of igneous and calea- reous rocks, and ores of Jalisco are reported entirely sur- rounded by limestone. It is interesting to note that these masses always occur in the vicinity of eruptive intrusions into the limestone and in some eases are entirely embedded in it. In some of the adjacent Cretaceous limestones was found a small weathered ammonite encrusted with limonite, showing that the limestone contains iron ore and that it concentrates upon the surface. In the silver-bearing fissures and veins of the same limestone which the writer has examined in many parts of Mexico there is always a residnum of excessively ferruginous clay. Im the unaltered limestones of the Coman- che series in Texas, notably at Austin, there are many nodules of iron oxide, especially in the Washita beds (the horizon of the Monclova limestones) which are the result of alterations of balls of pyrites. Along the veins and faults of Barton creek are deposits of ferruginous clay derived from the apparently pure white chalky limestone. The fissure at the contact of the Comanche limestone and diorite in which these Mexican ores are deposited can readily be explained by the mountain stresses or chemical solution of the limestone. The diorite is cross or double jointed and the fissures are filling with limonite by hydrous deposition, as can be seen in every crevice. We learn that certain Norwegian geologists have thus explained the origin of iron deposits in that country, but it is not pro- posed to maintain that the Mexican ore bodies so originated, although Barcena the eminent Mexican geologist asserts that in the mineral district of Agostadero, in the State of Jalisco, one can see specular iron ore in process of formation in the feldspathic rocks, through the agency of percolating waters charged with the hydroxide of iron, and percolating into the fissures of the rock. * Tratado Geologica, etc., por Mariano Barcena; Edicion de la Secretaria de Fomento. Mexico, 1886, p. 90. R. T. Hill— Hematite and Martite of Mexico. 115 The most interesting fact is the unusual geological age of the ore, and its occurrence different from any of our own country, unless the ore at Van Horn, in Trans-Pecos Texas, a part of the same geological provinee, is similar.* The principal specular ores of the United States are from the older Paleozoic and Archeean rocks, and as we proceed upward in the geological column they decrease in compact- ness and in luster. In fact the Mexican ores have a strong resemblance to those of the Superior district, and practical miners often speak of them as identical, a mistake which is further instigated by the Paleozoic aspect ‘of the Mesozoic and Tertiary phenomena of the region. The diorite is called “oranitico” by the natives, and is spoken of as granite by one of our prominent mining engineers.+ ‘The coal fields of the Sabinas, which extend to within thirty miles of the iron deposits have been often referred to as Carboniferous and Triassict until their Laramie age was shown by Dr. C. A. White, in 1886. The massive Paleozoic-looking limestone is undoubtedly of Lower Cretaceous age, and contains the char- acteristic Terebratulas, Pectens, Limas, Aviculas, Monopleuras, Ammonites, Radiolites and Nerineas of the Comanche Series of Texas, and is the result of alteration of the same beds which have a chalky aspect in the non-mountainous portion of the latter state. This limestone was published as Silurian by Rock,§ and Frazer received conditional opinions from Prof. Angelo Heilprin and James Hall to the effect that it was probably of Carboniferous age. | The diorites, as shown by their intrusion through the Comanche limestone at the Sierra Mereado of Monelova, and through both the limestone and the Laramie beds in the Sierra Candella, are clearly of post-Cretaceous age. Mr. Whitman Cross, of the U. 8S. Geological Survey, has kindly studied these for me, and his mineralogical notes areappended. His remark that they strongly resemble certain post-Cretaceous eruptives in Colorado, is an important point. These diorites have a wide distribution over the Mexican plateau. It is very evi- * The writer has seen masses of ore from Van Horn which resemble in mineralogical characters the Mexican ore. + Dr. Frazer in the paper already cited, speaks of the diorite both of the Sierra de Mercado of Monclova and of the Carrissal and Villadama regions as ‘‘ granite.” + Mr. W. H. Adams. in an otherwise excellent paper refers these coal fields to the Trias. See ‘‘Coal in Mexico: Santa Rosa District,” Trans. Am. Inst. Min- ing Engineers, vol. iii, pp. 25-28, 1874. § Report on Kxaminations of the San Rafael Mining Company’s Mines, by Adolphe Rock, Mobile, 1876. | Both of these geologists stated that the paleontologic evidence furnished them by Prof. Frazer was insufficient to accurately determine the age of these limestones, and that their opinions were largely based upon their lithologic characters. See Dr. Frazer’s paper, previously cited. 116 RL. T. Mill—Hematite and Martite of Mexico. dent that the iron ores are of later age than the rocks in which they occur, and this period was probably near the Eocene, for many of the basin plains of Mexico similar to that of Monclova in which the debris of the iron ore is found, contain the Loup Fork and Equus vertebrate Tertiary faunas of Cope. Having now described the geology of the Monclova ores as a typical locality of these peculiar Tertiary Mexican martite hematites, it may be well to examine the distribution of similar occurrences in Mexico. The local geology of Monclova, is typical of the geology of the whole of the Mexican mountain- ous (plateau) region, which may be briefly described as rem- nants of numerous folds of Comanche limestone (also the Laramie sands and clays in the northeast), frequently broken by protrusions of eruptive’ material, and separated by basin valleys, largely covered by the debris of the mountains. Only along the southern border of the plateau and in the extreme northwestern States are the older rocks of the Archean or Paleozoic exposed.* All the following localities of iron ore are from this region of Cretaceous limestone and Tertiary eruptives, with the possible exception of Prof. Silliman’s locali- ties in Sinaloa, where Carboniferous limestones also occur as well as the Cretaceous. The Sierra Candella Beds.—Seven miles west of the town of Salomon de Botia, and about sixty miles east of Monclova near the Mexican National railway, the writer examined several large deposits of ore similar in composition and occur- rence to that of Sierra de Mercado at Monclova. Although an entirely different group of mountains from those of Mon- clova, the. Sierra Candella consists of the same Comanche limestone, and dioritic eruptives. The Laramie beds however occur as foot hills on both sides of the Sierra Candella. The Sierra de Mercado of Durango.—About three hundred miles southwest of the Sierra de Mercado of Monclova is the Sierra de Mercado of Durango, commonly known as the iron mountain of Durango. It was from this locality that the oc- currence of martite was first noted by Prof. Silliman. The mountain has been well described by Mr. John Birkinbinet who says, ‘The hill is nearly a mile long and a third of a mile wide, and from four to six hundred feet high.” ..... “I am inclined to believe that the Cerro.de Mercado is formed of one or more immense lenses of specular ore, standing vertically, the fragments of which have for ages been thrown down to *The writer has reserved for a future paper the discussion of the general geology of the region. + Loe. cit. R. T. Hill—Hematite and Martite of Mexico. ALTA form the slopes of the mountain as a talus.” .... “Iam free to say that after having visited the iron mines of the United States, I have found nothing as yet to compare as to quantity in sioht with the Cerro de Mercado of Durango.” Unfortu- nately there has been no attempt at a description of the geology of this mass except that given by Wiedner,* whose allegation that it is the cone of an ancient volcano is erroneous, as can be seen by referring to Mr. Birkinbine’s excellent pic- ture of the mountain which was reproduced in this Journal.+ The only mention throwing light upon the nature of the country rock is that given by Prof. Silliman, who says :t “From samples of the country rock which I find in Mr. North’s collection the (enclosing) walls are of purple por- phyry; which would indicate that the Durango mass is accompanied by eruptive rocks as in the other cases men- tioned.” Inasmuch as the iron has been smelted for many years in primitive furnaces, requiring fluxes without rail transportation, it is very probable that the Comanche lime- stone (the chief sedimentary rock of Durango) cannot be very far distant from the mines. Prof. Silliman’s descrip- tion of the martite and hematite ores of Durango makes them appear to coincide so perfectly with those of Monclova, that it is diffienlt to believe otherwise than that the two deposits are geologically related. Jalisco.—tlron has been smelted for many years in this State, in the vicinity of Tula, southwest of Guadalajara. The deposits have been briefly described by Mr. J. P. Carson.§ According to this writer, the ore occurs in four distinct dis- tricts. The Amole mine in the district of Tula is bounded on one side by “a trap dyke” and on the other by a shaly dis- jointed sand rock. In the other districts the ore occurs under conditions similar to those of Monclova. In the district of Chiquilistlan, Mr. Carson says “the formation is limestone— probably Tertiary—greatly upheaved by volcanic action and penetrated in various directions by volcanic dykes.” In the Tecotes mine the “vein is what is termed segregated, occu- pying a space between parallel seams of limestone.” The Los Animas mine, which he says can be traced for a distance of over one thousand feet is also in a segregated vein of lime- stone.” These limestones, instead of being Tertiary, as con- ditionally stated by Mr. Carson, are very probably the Coman- che limestones of the Cretaceous, for Barcena describes them as Cretaceous and gives a list of fossils which are char- * Quoted by Mr. Birkinbine. +See Prof. Silliman’s paper previously cited. t Loe. cit. $ Iron Manufacture in Mexico, by J. P. Carson; Trans. Am. Inst. Mining Engineers, vol. vi, 1887-88, pp. 399-415, 118 R. T. Hill—Hematite and Martite of Mexvreo. acteristic Comanche species. The latter author also publishes a map of Jalisco, in which the eruptive rocks in the vicinity of these mines are for the most part called dioritic.* Sinaloa.—Prof. Silliman, in the valuable paper referred to, describes several occurrences of martite in Sinaloa. Almost nothing is known of the general geology of this State, but from the descriptions given of the ores at Tepuche, Beseuino and Cosolu, the conditions seem similar to those of Durango and Monclova. He says that the iron of Tepuche “occurs in a porphyry resembling that of the Sierra de Mercado” (of Durango), and that those of Cosolu are surrounded by ealeare- ous rocks. The localities also yield magnetite. Hidalgo, Mihoacan, Queretaro, Zacatecas and San Luis.— There are many references to ores in these States in the Mexi- ean geological literature, which lead to the inference that they are of the same character as those we have described. In Queretaro, Barcena mentions the occurrence of a hematite which he ‘believes is contemporaneous with the porphyry.” He also describes the occurrence of hematite associated with tin in a Tertiary porphyry in the Meza de los Caballos of Zacatecas. In Hidalgo he says there are large beds of hema- tite, mixed with magnetite, in the post-Cretaceous formations. He refers to many other localities in the States of Jalisca, Durango and Mihoacan, and says that these ores constitute the chief deposits of iron in the republic.t Virlett mentions the occurrence of iron ore at the contact of limestone and diorite in the eastern Sierra Madres, in the State of San Luis. Gruerrero.—One of the most interesting descriptions of iron ore in Mexico is that given by Manross in this Journal for May, 1865. He mentions eight localities of the occurrence of iron ore in Guerrero, which, with the exception of his age determinations, greatly resemble the Monclova and Durango deposits. ‘The first of these is situated at a distance of four miles from Mescala. It is a vein twenty five feet wide and nearly vertical, and consists of solid magnetite ore.” Another is ‘three hundred feet high, half a mile long and fully one- third of its bulk is pure magnetic ore.” It “contains a bed of limestone at its summit.” Another is four hundred yards long and one hundred yards wide. The unfortunate death of this young student renders it impossible to ascertain further data from him concerning the ores. At the time he wrote his * Ensayo Estadistico del Estado de Jalisco, etc, por Mariano Barcena. Mexico, 1891. + These notes are taken from various observations following the mineral de- scriptions in Barcena’s “ Tratado,” already quoted. Other notes on iron are found in his various statistical essays on tle separate States of Mexico. t Coup d’ceil général de Ja topographie et la geologie du Mexique, ete., par M. Virlet d’Aoust, Bull. Soc. Géologique de France. 1866. Le. 7. Hill—Hematite and Martite of Mexico. 1) descriptions, however, the massive Cretaceous limestones of Mexico were generally supposed to be of Paleozoic age, and the difficulties of liability to mistake the superficial martite of the hematite deposits for magnetite has already been cited in the experiences of Mr. Birkinbine, Prof. Silliman and the writer. Mr. Manross himself remarks that “what is still lacking is the evidence of the fossils” to prove that a coal vegetation has once existed in these latitudes.” Sefor Cas- tillo, upon his geological map of Mexico gives no sedimen- taries of Paleozoic age in this region, the only ones indicated being Cretaceous. He does give metamorphic and primitive rocks however and eruptives, and the Archzean which has been reported east of this State may extend into it. In conclusion it may be said that the occurrence of such large masses of hematite in rocks of Cretaceous and Tertiary age is of great interest, and that the Mexican ores of this character, accompanied by martite have a wide occurrence in that republic, which will be an important factor in the future iron supply of the world. Prof. Frazer remarks that it would pay to import these ores for mixture, as Cuban ores are now imported. Ten years ago Prof. Silliman said of the Durango iron: * The enormous mass of valuable iron ore, thanks to the near approach of the railway of Mexico, is now likely to become of commercial importance.” Exactly ten years from the month of publication of his article the Mexican International railway erieneted the completion of its line to the foot of the Durango iron mountain, connecting it by rail with the coal fields of the Sabinas, and the prophecies of Profs. Silliman and Birkinbine are on the eve of fulfillment. The accompanying note by Mr. Whitman Cross upon the eruptive rocks of Coahuila are of interest in connection with the discussion of the iron deposits. The general geology of the region will be given in another paper. Igneous rocks from the Coal and Iron regions of Coahuila and Nueva Leon, Mexico, collected by by Dis SST NOx; WHITMAN Oross. 1. Basalt overlying Laramie coal fields.—Mesa, 6 miles east of Santa Rosa de Musquez. A rock of simple normal constitu- tion. Olivine crystals in various stages of decomposition are the only porphyritical constituent. Groundmass of small plagioclase staves and augite grains. There seems to be no Am. Jour. Sco1.—TuHirpD SERIES, VOL. XLV, No. 266.—FEBRUARY, 1893. 9 120 W. Cross Igneous Rocks of Mexico. magnetite in usual form, but a black substance occurs in angu lar spaces between other minerals. This seems to be secondary. There is no glass base. Composite. quartz grains are surrounded by zones of augite as deseribed by Id dings, Diller and others. 2. Diorite from Sierra Mercado of Monclova.—A quartzose hornblende-diorite. ‘The rock is a mass of small stout plagio- clase crystals and irregular hornblende prisms pressed close together with quartz as the chief cementing substance though there is probably a little orthoclase, and plagioclase also, as interstitial matter. This rock is quite different mineralogically from the diorite of Sierra Candella. 3. Hornblende-porphyrite—The rock has hornblende and plagioclase phenocrysts in a prominent finely granular erypto- crystalline groundmass. I[t might be a porphyritic equivalent of diorite No. 2. 4. Vein matter in diorite.— A fine-grained mixture of orthoclase and quartz. Has no microcline or micropegmatite, or plagioclase. Is like vein matter commonly found in granite or diorite masses. 5. Hornblende-porphyrite—Hornblende and plagioclase are the main phenocrysts and the groundmass is unevenly granu- lar, orthoclase being the chief substance. There is very little if oy quartz. Augite-diorite.—Sierra Candella. This rock is chiefly ede up of a dark green angite in imperfect prisms, plagio- clase in tablets with very strongly marked zonal str ucture, and orthoclase, the latter surr ounding the plagioclase in a regular growth. There is some biotite, occasionally appearing in blades nearly an inch long ; hornblende is intergrown with augite in the outer zone of some crystals. It is never very intricately intergrown with augite. Quartz occurs in a few small grains, and magnetite, titanite, apatite and zircon, are accessory as usual. This rock differs in composition from the other diorite in the presence of augite in place of hornblende, and in the abundance of orthoclase. These diorites are deep-seated eruptives similar in composi- tion to several Colorado occurrences which were erupted in some period not long after the Cretaceous, as they cut upper Cretaceous strata, but are affected by orographie movements of early Tertiary time. The porphyrites are no doubt equivalent to the diorites, but from smaller masses and perhaps consolidated nearer the sur- face. H L. Wells—Cesium- and Potassium-Lead Halides. 121 Art. XVI.—On the Coesium- and the Potassium-Lead Halides ; by H. L. WELLS. As a continuation of the work on double halides, in this laboratory,* a study of the cesium-lead salts has been under- taken by Messrs. G. F. Campbell, P. T. Walden and A. P. Wheeler. These gentlemen have carried out the investigation with much enthusiasm and skill, and I take pleasure in express- ing my obligations to them. They have established the fol- lowing salts : Cs,PbCl, Of A ed OB pei iar WL ong a CsPbCl, CsPbBr 4 CsPbI, CsPb,Cl, CsPb,Br, Pawo These results showed the existence of three types of lead double halides, the first of which fails to conform with Remsen’s lawt concerning the composition of this class of bodies. Since the recent investigations of Remsen and Herty§ had indicated the existence of only a single type of potassium-lead _ halides, a new investigation of these seemed desirable, espe- cially since these authors had denied the existence of Boullay’s salt, K,PbI,, which corresponds to one type of the new cesium compounds. I have, therefore, undertaken this work and, as a result, have obtained the following salts: Homie ls (9 K,PbBr,. H,O Go ; 3K PbBr, . H.O SKPbOL,.H,0 4) EPR “Ho | KPbI, . 2H,0 KPb,Cl, KEP HIBEN Wim wneaN Reeue: It is to be noticed that neither Boullay’s iodide nor any corresponding chloride or bromide was obtained among these salts. On the other hand, the compound K,PbBr,. H,O be- longs to a type which had not been discovered among the ceesium salts, so that, taking the cesium and potassium series together, the existence of four types of double lead halides is shown. The compound K,PbBr,, the anhydrous form of the salt just mentioned, is ascribed to Lowig,4 but although iodides belonging to the same type have been described, K,PbI, . 4H,O by Ditte** and K,PbI,.2H,O by Berthelot,t++ neither Remsen * This Journal, III, xliv, 155, 157 and 221. + This compound is dimorphous. ${ Am. Chem. Jour., xi, 296. § Am. Chem. Jour.. xiv, 107. || Ann. Chim. Phys., II, xxxiv, 336 ( 1827). “| Gmelin’s ° : Handbook, ” Hnelish Hd. of 1850, v, 162. ** Ann. Chim. Phys., V, xxiv, 226, 1881. ++ Aun. Chim. Phys., V, xxix, 289, 1883. 122 HL. Wells—Ceesium- and Potassium-Lead Halides. and Herty nor I have been able to prepare them. Although these iodides and Boullay’s salt, K,PbI,, belong to types which certainly exist, I am inclined to believe, with Remsen and Herty, that the products which gave these formule were mixtures of KPbI,.2H,O and KI. The absence of more than one iodide in the cesium series strengthens this view. Remsen and Herty obtained the salt KPbI,.2H,O under wide variations of conditions and I have confirmed their results. This salt was first obtained by Boullay* and analyzed by him, after drying over lime, in an anhydrous condition. Berthelott has deseribed a compound, K ie pslee 6H,O, which differs but slightly in required composition from the above salt, and his description of it agrees with that compound. There is no doubt, therefore, that he really obtained the com- pound KPbI,.2H,O and that his analyzed products were slightly contaminated with potassium iodide. Berthelot at- tributes K,Pb,I,, to Boullay. The latter chemist, however, derived the correct formula, equivalent to KPblI,, from his analysis, but since this did not agree closely with theory, Gmelint derived the above-mentioned formula from it, and this has been frequently copied in more recent chemical litera- ture. Schreinemakers,§ in connection with an investigation on the equilibrium of the double salt of iodide of lead and potassium in aqueous solution, has assnmed that Ditte’s formula was cor- rect as far as the composition of the anhydrous compound was concerned. By making a number of water determinations, without determining lead, potassium or iodine, he arrived at the formula K,PbI,. 25H, (Oupialt Hs absolutely certain, from his description of the salt and his method of preparing it, that he had the compound KPbI,.2H,O0; moreover, his water determinations. 5°52, 5°72, 5°89, 5:93 and 5°16 per cent, agree satisfactorily with the calculated amount, 5-90, for this salt. Remsen and Herty made only a single chloride, and likewise only one bromide. The other chloride, and the ‘i bromides belonging to other types crystallize ‘beautifully and. are as easily made as the salts which they prepared, and it is a strange coincidence that the latter happened to correspond in type to the iodide which they had obtained. I have confirmed the composition of their bromide, KPbBr,.H,O, but their chlo- ride, to which they gave the formula KPbCl, is evidently identical with the compound which I have found to be un- doubtedly hydrous, 83K PbCl,. HO. * Ann. Chim. Phys., Il. xxxiv, 336, 1827. + Ann. Chim. Phys, V, xxix. 289. 1883. t ‘ Handbook,” English ed.. 1850, v, 161. § Zeitsebr. Physikal. Chem., ix, 57, 1892. H. L. Wells—Cesium- and Potassium-Lead Halides. 123 Léwig, as already mentioned, has described the compound K,PbBr,. I have been unable to find his original article, but from the fact that I have not obtained an anhydrous form of this compound, I believe that he overlooked the water of erystallization or dehydrated the salt before analyzing it. A bromide, K,Pb,Br, is mentioned by Berthelot.* He does not give any analysis or description of it, and I am convinced from my own experiments that he obtained a mixture of Keb Bra. HO) and KEb, Bre Stroheckert states that he produced three different chlorides of potassium and lead by mixing potassium chloride and lead nitrate solutions. It is remarkable, considering the abundance and cheapness of the materials and the ease with which large quantities of the double salts can be made, that he did not obtain them in sufficient quantities for exact analyses. Since I have sueceeded in making only two double chlorides, I be- lieve that one of Strohecker’s salts, which he describes as feathery, was simply lead chloride. The results of previous investigators may be summed up by saying that it is probable that no potassium-lead halides have been correctly described, if water of crystallization is taken into consideration, except two of Remsen and Herty’s salts, KPbBr,. H,O and KPDI, . 2H,0. Method of Preparation. Both the czesium and potassium salts have been investigated, in every case, by making hot, aqueous solutions of the com- ponent halides and cooling to crystallization. Some previous investigators had used solutions of lead nitrate and an alka- line halide for the purpose, but their example has not been followed, because it was not believed that the presence of an alkaline nitrate would in any way facilitate the operation. and it was feared that it might incur contamination in some cases. The conditions were gradually varied from a point where the alkaline halide crystallized out, to a point where the lead halide was deposited uncombined, and the experiments were so carefully carried out and so frequently repeated that it seems scarcely possible that any double salt was overlooked. The salts have been made on a rather large scale. In the case of the cesium compounds, the rarity of the material made it necessary to perform the separate experiments with only about 50 or 75 grams of a cesium halide, but in making the potassium salts 400 or 500 grams of a potassium halide were frequently used. * Ann. Chim. Phys., V. xxix, 289, 1883. ¢ Jahresbericht, 1869, 282. 124. A. L. Wells—Cesium- and Potassium-Lead Halides. Solutions which were neutral or slightly acid were generally used. The effect of the presence of a large amount of free acid, hydrochloric, hydrobromie or hydroiodic, as the case re- quired, was also carefully studied, but these had no apparent effect upon the results. Very. large crops of the potassium salts were sometimes formed, so that the homogeneity of the mass was doubtful. In such cases the greater part of the crop was removed and satisfactory crystals were obtained by dissolving the remainder in the mother-liquor by the aid of heat and cooling. The cesium material used was wholly from the pollucite of Hebron, Maine.* The salts were carefully purified for this investigation. Godeffroy’s methodt was found to be very satisfactory for the purpose of separating cesium from the sodium and potassium which accompany it in the mineral. Kahlbaum’s potassium chloride, bromide and iodide were usually used for making the potassium salts, but for a few experiments the ordinary medicinal potassium bromide was substituted. Since some of the analyses of the double bro- mides show an excess over 100 per cent, it is suspected that the salts contained a little chlorine. Calculation shows that one per cent of chlorine replacing bromine would cause an excess of 0°71 per cent if the chlorine was weighed as silver chloride and calculated as bromine. The lead halides which were used were prepared by our- selves from reliable materials. General Properties. ® The lead double halides are all decomposed by water, and the presence of a large excess of the alkaline halide is neces- sary for the formation of all the compounds to be described except CsPb,Cl, and CsPb,Br,, which are almost stable with water. The concentration of the alkaline halide solution evidently determines, in the cases of the chlorides and bromides, the type of salt produced. Since the simple cesium halides are much more soluble than those of potas- sium, it is possible to use them in much more concen- trated solutions, and the salts Cs,PbCl, and Cs,PbBr, are readily obtained. In the case of potassium bromide the solu- tion becomes saturated with the simple salt by concentration just beyond the point where K,Pbbr,.H,O is obtained, and with potassium chloride, which is ‘less soluble than the br omide, the limit is reached at the compound 3K PbCl,.H,O. The apparent existence of only a single double iodide, both with cesium and potassium, is remarkable since cesium iodide is * This Journal, III, xli, 213. + Berichte d. Chem. Ges., vii, 375. H.. L. Wells—Cesium- and Potassium-Lead Halides. 125 very soluble and potassium iodide is much more soluble than the bromide and chloride. On account of their decomposition by water, no determina- tions of the solubility of the double halides have been made, but it was noticed that the cesium compounds were much. less soluble in the saline solutions than the corresponding potas- sium salts. This relation corresponds with the observation of Godeffroy,* that while the simple salts increase in solubility from potassium to cesium, the double and complicated salts show a decrease in this direction. All the chlorides and bromides described in this article are colorless, or in one case nearly so, except two cesium salts, CsPbCl, and one modification of CsPbBr,. The first of these is pale yellow and the other bright orange. These colors are very remarkable since the simple halides from which they are made are all colorless. I have previously observed a similar ease, where a colored double halide was formed from two colorless halides, in the compound CsHeBr,.t Both double iodides are yellow, the hydrous potassium salt being the paler of the two. Analytical Methods. Great care was used in selecting homogeneous material for analysis. The erystals were dried as rapidly and thoroughly as possible by pressing them between smooth filter-papers, and where the substance did not lose its luster by the operation, it was then exposed to the air for several hours. Water was determined by collecting and weighing it in a calecium-chloride tube, the substance being ignited in a com- bustion-tube, behind a layer of dry sodium carbonate, in a cur- rent of dry air. The water lost over sulphuric acid or at certain temperatures was determined by the nsual methods. Lead was determined in two ways. With all the cesium salts the substance was dissolved in hot water (an easy opera- tion with all these salts, but impracticable in the case of some of the potassium compounds), and all except a trace of lead was precipitated by ammonium carbonate in presence of am- monium hydroxide. The precipitate of lead carbonate was removed by filtration and the remaining trace of lead was precipitated by passing hydrogen sulphide into the alkaline solution. The lead sulphide was collected and ignited by itself in a porcelain crucible. The amount of this was so small that it was evident that no appreciable error would arise from any lead sulphate that the ignited residue might contain, so that the main precipitate of lead carbonate was ignited in the same * Berichte d. Chem. Ges., ix, 1365. + This Journal, THI, xliv; 227. 126 HI. £. Wells—Cesium- and Potassium-Lead Halides. erucible and the whole was weighed and calculated as lead oxide. A different method was selected for the determination of lead in the potassium compounds, for the reason that some ot them could not be readily dissolved in hot water, and it was found to be more convenient and expeditious than the other. About one gram of substance was dissolved in about 10° nitric acid (sp. er. 1°20), about 2° concentrated sulphuric acid, previously diluted with water were then added and the nitrie acid was removed by evaporation. After diluting with about 25° of water and cooling, the Jead sulphate was collected in a Gooch crucible, washed with very dilute sulphuric acid, ignited and weighed. ; In order to determine cesium, the alkaline solution from which the lead had been removed was concentrated until the ammonium carbonate, hydroxide and sulphide had been nearly or quite removed, a small excess of sulphuric acid was added, and, after evaporation and ignition, normal cesium sulphate was obtained by igniting in a current of air containing am- monia and this was weighed. The filtrates from the lead sulphate did not contain an appreciable amount of lead. Normal potassium sulphate was obtained from these solutions by evaporating, igniting and heating in an ammoniacal atmosphere. The halogens were determined as silver halides. Where the substance could be completely dissolved in hot water, an excess of silver nitrate was added to the hot solution and it was afterwards acidified with nitric acid. When it happened that the lead halide remained partly undissolved, the nitric acid was not added until this had been completely decomposed by long digestion on the water-bath with an excess of silver nitrate. The precipitates were collected and weighed in Gooch erucibles. The Coesium-Lead Chlorides; by G. FL Campbell. Cs,PbCl,— When lead chloride is dissolved, by the aid of heat, in a solution of cesium chloride which is so concentrated as to be nearly saturated when cold, this salt is deposited on cooling in the form of brilliant, white rhombohedrons. Crys- tals having a diameter of 2 or 3°" were sometimes obtained. Two entirely separate crops were analyzed, both of which were undoubtedly free from other compounds. Calculated Found. for Cs,PbClg. Cesium aa 55°60 56:08 55:90 Wpeadie era pec Maat cia 21°63 21°75 Chicriite eee 21:97 22:23 92°35 99°89 100°00 HT. L. Wells—Cesium- and Potassium-Lead Halides. 127 CsPbCl,.— On gradually diluting the concentrated solution of cesium chloride, such as was used in making the previous salt, and dissolving lead chloride in it as before, a point is soon reached where short prismatic crystals of small size and of a pale yellow color are deposited on cooling. Three dif- ferent crops of apparently pure crystals were analyzed. Calculated Found. for CsPbCls. Cxsiumeee eolk35 30°54 30°13 29°79 Meades 252 44:99 45°28 46°29 46°36 C@hilorine_.— 23°85 32716 DOT Ah, 23°85 100°17 99°57 100°13 100°00 Cs Pb,Cl,— Experiments with still more dilute solutions, carried out in a similar manner, gave, under wide variations of conditions, this salt in the form of thin white plates which were often several millimeters in diameter. These plates pre- sented marked variations in habit, which were apparently due to changes in the conditions under which they were made. In two crops, of which A and B are the analyses, the plates were uniformly rhomboidal in form. Two other crops, C and D, were made up of lengthened plates, so twinned as to form feathery aggregates. In another crop, E, made froma more dilute solution than the others, the plates were apparently square. Found. Caleulated A. B. C. D. EK. for CsPb.Cl;. Cesium __ 19°99 18°44 18:27 Bega > 1S 18°36 eager Oley elGe 5706) O6.98 + 57508 SY PING) Corinne is eee OAC Ae hae OA HOMO 481 24°48 100°07 99°88 100°€0 The three different habits in which this salt crystallizes are so distinct in appearance that, before the samples were anal- yzed, it was supposed that they were separate compounds. It appears probable that the compound is at least dimorphous. The Cesium-Lead Bromides ; by P. T. Waiden. Os, Pb Br,,—This salt is produced, in concentrated solutions, similarly to the corresponding chloride. Like the latter salt it forms white rhombohedrons. The crystals were usually not over | or 2™™ in diameter. ‘Two separate crops were prepared and analyzed. 128 HL. Wells—Coasium- and Potassium-Lead Halides. Calculated Found. for Cs,PbBrzg. @eesia ma ee eS Gl ees 43°64 Reads. Ceiter ay Cees 16°83 16°83 16°98 ESLOMLMe) oes aes = ete 39°24 39°38 39°38 99°68 99°58 100°00 CsPbBr,.—This compound is dimorphous. One modifiea- tion forms small prisms of a bright orange color, the other is pure white and crystallizes in slender needles. “The orange salt is obtained when lead bromide is dissolved in somewhat more dilute solutions of cesium bromide than those required for the formation of Cs,PbBr,, and there is a narrow range of conditions where it crystallizes upon the latter salt. There i iS, therefore, no evidence of the existence of an intermediate compound, Cs,PbBr,, corresponding to one of the potassium- lead bromides. Whenever solid lead bromide is added to a concentrated solution of cesium bromide, it instantly loses its white color and takes on that of the orange salt. The white needles are formed in solutions which are slightly more dilute than those required for the orange modification. The limits of the conditions, under which this white salt is formed, are very narrow and a great many trials were necessary before satisfactory crops were obtained. Two distinct samples of each salt were analyzed. The white needles were not abso- Iutely free from the orange compound, but there is no doubt that they were sufficiently pure to show their composition accurately. Found. Calculated Orange salt White salt. for CsPbBrs. Cesium oOo Ona alo als DE Wey) 22°93 Readies 2a2 35°69 35°39 35°24 35°88 35°69 Bromine -. 41°37 41°34 Ac Ay, | VAGASS 41°38 100°25 99°86 99°73 99:82 100°00 On heating the white modification to about 140°, it gradu- ally assumes the exact color of the orange salt, without chang- ing its external form, and this color is permanent on cooling. CsPb, Br,—This salt is produced in solutions which are still more dilute than those from which the preceding com- pounds are obtained. It was first noticed at a volume of about 160° of a solution containing about 50% of cesium bromide. It continued to form, on further dilution and the addition of lead bromide, until the volume reached 1250°, when lead bromide began to be deposited. The conditions under which the salt is formed are, therefore, very wide. The A. L. Wells—Coesium- and Potassium-Lead Halides. 129 compound erystallizes in thin, white plates, which, like the corresponding chloride, present considerable differences in habit. Plates having a diameter of about 5™" were some- times obtained. Three separate crops of crystals were anal- yzed. Calculated Found. for CsPb2Brs. Cesium.... 14°13 14°35 riya 14°05 heads se. 43°39 43°72 43°45 Aerial Bromine... 42°23 42°23) awh 49°94 99°75 100°28 100°00 The Cesium-Lead Iodide, and some Mixed Double-Halides ; by A. P. Wheeler. OsPbI,.— Under a great variety of conditions this was the only double iodide that could be produced. The compound is but slightly soluble in hot cesium iodide solutions, so that the crops obtained were always small. It forms very slender, rectangular prisms which are yellow in color. The following analyses were made on separate products: Calculated Found. for CsPblIs. Cesium. ue 17°90 ee 18°45 Weadevanae ta S38 27°40 28°71 Vodines ys. mee ee 50°83 D220" 52°84 99°11 100:°00 Three double salts have been made by dissolving lead bromide in solutions of czesium chloride. The analyses show that the two salts do not combine unchanged, but that there is usually an extensive exchange of halogens. Each of the products must be considered, therefore, as a mixture of a double chloride with the corresponding double bromide. Us, Pb( Cl, Br),—This was produced in rhombohedrong, like the chloride and bromide. Two crops were analyzed. Found. resins seep ee 54°65 55°50 TEE (6 lias fa eat fa a 19°30 18°61 Chlorine eee 15°89 19°90 SGLOMmMUner se os oa ee 9°52 4°03 1380 A. L. Wells—Cesium- and Potassium-Lead Halides. Os Pb( Cl, Br),.—This oecurred in small rectangular prisms, like the chloride and bromide and having a yellow color inter- mediate between them. Two crops gave the following analyses : Found. Cesium 222 tee ae 30°24 30°50 1 Bef: We Mes nae Sop ay 3, Abalos} 43°55 Chiorines= “eee 91°44 18°94 JEIRG INNS 22 os Bowe ke 4°00 8°79 99°91 101°96 Ration br: Cleese WOM i oie abo) CsPb, Cl, Br),—This was obtained in white plates resem- bling the two double salts. Two products were analyzed. Found. Cxesiumy neers 18:94 Heh Wea dee Woes santas ee 51°40 51:97 Chlorine sae eee 16°29 19°31 JerRoNTay NONE ey we ILS} 8°62 99.90 Ratio BrCl ss: e258 15 The Potassium Lead Halides. In studying these bodies care has been taken to record the conditions under which they were made. ‘These conditions, in many cases are only approximately given, because uncertain quantities of salts had often been removed from the solutions, either for analysis or in order to obtain smaller and better crops of crystals. A large number of analyses have been made in some cases. This was due to the fact that the salts often varied so little in appearance that it was necessary to analyze many products in order to identify them and to be certain that they were not different compounds. 3H PbCl,. H,0.—When lead chloride is dissolved in a hot solution of potassium chloride which is so concentrated as to be nearly saturated when cold, this double salt is deposited on cooling. It forms brilliant prismatic crystals which are largest in the most concentrated potassium chloride solutions. The largest crystals obtained had a length of more than 10™™ and a diameter of 1 or 2™™. It was noticed that, when sufficiently concentrated solutions were used, pure potassium chloride erystallized upon this compound, and no evidence was ob- tained of the existence of a double salt containing a larger proportion of potassium chloride than this. H. L. Wells—Cesium- and Potassium-Lead Halides. 131 The following table gives the approximate conditions under which the five samples which were analyzed were made. Volume KCl. PbOle. Volume. for 1gKCl. SAU eet eA OS 805 1100°° QRec | Byes cs ce 400 80 1200 3 Ce SES 15.0 40 450 3 [Doser ey aera 160 25 350 34 1D eee ae 300 55 1500 45 The results of the analyses are as follows: Calculated for A. B. @ D. E. 3KPbCl, . H.0. KGRE ee TSB. NO! 107 9yake wn ee sep 10°90 Pics OTLOs BINS yes Bye Be ans Glob BOOM POE. a PRI yy Aneel e. 29°70 ROM nu es On = Geta] oi. sales 1:67 100-20 100-04 100-00 All the samples were thoroughly air-dried before they were analyzed. By this treatment the crystals did not lose any of their luster. A finely pulverized portion of sample A. lost only 0:02 per cent in weight after standing over concentrated sulphuric acid for eight days. The same sample suffered an additional loss of 0°23 per cent when heated for twelve hours in a steam drying-oven. The water was not rapidly given off until a temperature of about 200° was reached. The salt decrepitates when heated rapidly to about 200°, corresponding in this respect to the salt which Remsen and Herty described as anhydrous and to which they gave the formula KPbOl,. There can be no doubt, therefore, that Remsen and Herty’s formula is incorrect. KPb,C,.—This salt is formed in more dilute solutions than those which produce the previously described compound. It occurs, like that compound, in white prismatic crystals, but it differs considerably from it in luster and form, so that the two salts can be distinguished by microscopic examination. The salt under consideration is anhydrous, and this fact makes it easy to distinguish this compound, when pure, from the other. Four analyzed crops were made under the following condi- tions : Volume KCl. PbCl.. Volume. for lgKCl. PARE A 28), 2008 508 TaOoss 74° ST esa pees 150 30 1100 7 Cressex 150 20 1100 74 Des here 250 55 1200 4-8 182 A. L. Wells—Cesium- and Potassium-Lead Halides. The analyses were as follows: Caleulated A. BE C. 1D} for KPhb.Cls. Potassium.. 6°14 5°97 6°18 6°07 6°20 ead: 64°74 66°43 65°85 65712 65°65 Chiorme 225.281 eae 28:18 28°08 28°15 Water os Oli aly Si pans Made 0:00 99°10 100°16 99°87 100:00 There was no indication of the formation of any other double chloride as the dilution was increased beyond that given for the above products, and when a solution containing 1 of KCl in 11° was used pure lead chloride was deposited. K,Pbbr,. H,O0—This salt is obtained by dissolving lead bromide in the most concentrated solutions of potassium bromide. It forms brilliant, prismatic crystals which are permanent in the air. The largest of these which were ob- tained were about 1™™ in diameter and 5"™ in length. A num- ber of crops were made under the following conditions : Volume KBr: PbBrs. Volume. for lgKBr. A eee OOS 708 700° 3 Bias 400 90 700 12 Cee oe! 400 120 800 2 Denon 400 130 650 1:6, UDA eg) 500 130 850 1; | rays eat 500 130 775 1,8 These products gave the following analyses : K. Pb. Breve) HO. j AY UE IMS aaah Ivara 34°25 51:47 2350100543 Re reeds ie 1221 34°59 = 1°21 275.1 == L002 Cape eel aes 11°89 34:47 o1°14 244—= 99°94 Die GN iw 12°37 34°50 51°35 up OTe Ue teiinnenmcttsr deat 34°26 51°40- 2°61 1h Sgn LZ AO We 3Sn8 9 Vola 2°57 = 100-62 PLES ILO t 12:55 33°21 51°35 2-89 = 100-00 This salt is apparently stable in the air, but it loses water very slowly over sulphuric acid. A finely powdered sample of A lost 0°23 per cent after remaining 12 hours in the desiccator, and the same portion suffered an additional loss 0°33 after eight days. A sample which was not pulverized lost only 0-09 per cent in 12 hours and, in addition, 0°17 per cent in eight days. About one-half of the water went off when the substance was heated for 12 hours in a steam drying-oven. At 200° the water is rapidly and completely expelled. H. L. Wells—Cosiuwm- and Potassiwm-Lead Halides. 1838 3K Pb Br,.H,0.—The conditions under which this salt can be made are rather narrow, and these conditions encroach upon those of the preceding compound, so that small differences in the amounts of lead chloride used or in the temperature of the solution are sufficient to cause the formation of the other salt. It forms brilliant, colorless, lozenge-shaped crystals which can be easily distinguished from the other compound. The crystals which were obtained sometimes had a diameter of 2ROn Oe The crops analyzed were made under the following condi- tions: Volume KBr. PbBry. Volume. for lgK Br. Ace ae 5008 1308 ; 950°° 1 IBS cess 500 130 1050 out OraGace! 500 140 900 125 Dias eee Pe 500 120 1050 one Begin ee 500 120 1125 24 The analyses were as follows: K. Pb. Br. H.0. ING Res eS Le 8°44 41°91 Sia W529 1B 2 es) 2 aia 8°02 42°71 48°95 H625==— O30 CE eee 8°60 4 Gl 49°16 1560 ==20.0°97 De Oe ea E8208 42°69 48:91 1°14 = 100°82 Vip Sato os Soa he tara haere 42°61 Betsy SUNY ai Wa AY Calculated for 3K PbBr,. H,O The salt is stable in the air. A sample, after standing seven days over sulphuric acid, lost only 0-04 per cent. The water is given off very slowly at 100°. EP Br, . 1,0.—This salt was described by Remsen and Herty. At summer temperature, about 25°, I was unable to obtain it, but by placing the mother-liquors from the preced- ing salt in an ice-chest, beautifully crystallized crops of it were obtained. Its formation was also noticed at laboratory temperatures when the weather was somewhat cooler than in mid-summer. It forms prismatic crystals. Some of those obtained were about 10™™ long and 2™™ in diameter. Two crops were analyzed. ° Mos 42°06 48°77 22 ——1'0,0;00 Calculated for Found. KPbBr;. H.0O. IRotassium= 49-7202. 8°24 7-90 TG TEeE (0 lhe Meek ES SA as Cee 41°23 41°20 41:06 TS ROMDUME Ae oe eee 47°81 earn 47°61 Wa Gers ae Seer ea fo 3°28 3°64 3:57 100°56 100°00 184. A. L. Wells—Cesium- and Potassium-Lead Halides. The salt is usually permanent in the air, but in dry weather the erystals gradually become opaque, and over sulphurie acid about two thirds of the water is rapidly given off. EK Pb, Br,—This salt crystallizes in square plates, sometimes 3 or 4™™ in diameter. It can be readily distinguished from the other double bromides, not only by its form, but from the fact that it quickly assumes a pale green color when exposed to daylight. On long exposure, or in direct sunlight, this color changes to a pale dirty-brown. I have observed that lead bromide itself becomes nearly black on long exposure to daylight. This fact does not appear to be generally known. The samples analyzed were made under the following con- ditions : Volume KBr. PbBro. Volume. for le KBr. iN Rtas ie fp ue 4008 130 1050°° 22 Sh sai ae es 400 150 1250 34 Cun aaa 200 75 1000 5) The results of the analyses are as follows: Calculated A, B. C. for KPb.Br;. Potassium soe soe A715 4°75 Ae Tal 4°58 Wedd Sees eu eis 49°25 49°11 48°48 48°53 Tes ge 47°03 46°98 46°89 46°89 10100 100°84 100°08 100-00 KPbI,.2H,O.—It has already been mentioned that thisis the only double iodide that either Remsen and Herty or I have been able to make. It forms slender, pale yellow needles, and is produced under a great variety of conditions. Twosamples were analyzed. A was made with about 450%KI, 75@PbI,, and 600° volume. For B about 4002KI, 45¢PbI, and 280° volume were used. Calculated AY 13) KPbi, . 2H.0. FZOVASSIIDMNE Ce. osleeyes 6°03 6:07 5:90 NDS eked Pipette aia BO MS: SOs Silo zal fodineye ye. is ere 57°57 56°99 57°46 Waters e cis etna 5:26 6:04 5°48 99°59 99°23 100°00 The salt is apparently stable in the air, but it loses water in the desiccator. Sheffield Scientific School. New Haven, Conn., October, 1892. J.B. Hatcher—Ceratops Beds of. Wyoming. 135 Art. XVIL—TZhe Ceratops Beds of Converse County, Wyoming ; by J. B. HarcHer. In the December number of this Journal for 1889, Prof. O. C. Marsh gave the name Ceratops beds to certain strata in the upper Cretaceous of Wyoming, Montana, and Colorado, containing the remains of horned Dinosaurs (Ceratopside) and many other reptilian and mammalian forms. Of these beds, those in the northeastern portion of Con- verse county, Wyoming, are best known and have been most thoroughly explored. Fully ninety per cent. of all the verte- brate fossils described by Prof. Marsh from the Ceratops beds were found in this region. This fact is sufficient to warrant a more detailed description of the stratigraphical and geograph- ical position of the beds, and of their geological and litholog- ical characters, than has yet appeared. Not only has this region proved especially rich in vertebrate fossils, but the Ceratops: beds seem to have attained a greater development here than has been noticed elsewhere. Since the present border of the beds is nearly that of the eastern shore of the fresh-waters in which they were deposited, and erosion has exposed many continuous sections in them down through the underlying Fox Hills sandstones and into the Ft. Pierre shales, this region offers exceptional advantages for determining the position of the Ceratops beds and for establishing their age upon stratigraphical as well as paleontological evidence. Geographical Position of the Ceratops Beds. The Ceratops beds of Wyoming have thus far been explored only in a very limited region in the northeastern part of Con- verse county. Going north from Lusk, a small station on the Freemont, Elkhorn, and Missouri Valley railroad, they first appear about twenty-five miles from that place, occupy- ing the summit and northern slope of a yellow sandstone ridge extending in a westerly direction from Buck creek to Lance creek and crossing the latter stream near the mouth of Little Lightning creek, a small tributary from the west. A short distance west of Lance creek, the Ceratops beds pass under other beds composed of very similar material, and pre- sumably of Cretaceous age. From Buck creek, the eastern border of the Ceratops beds has been traced in an almost con- tinuous exposure, extending northeasterly to the Cheyenne river, and crossing this stream a short distance below the mouth of Lance creek. From this point, it takes a more Am. Jour. Sci1.—Tuirp Series, Vor. XLV, No. 266.—Frspruary, 1893. 10 136 JS. B. Hatoher— Cerutops Beds of Wyomeng. northerly direction, and skirting the western slope of the Black Hills, it has been traced to the north line of Converse county and on into Weston county. As stated above, the eastern shore of the fresh-waters in which the Ceratops beds were deposited was nearly that of the present border of these beds. The eastern limit of the fresh-waters was confined to the western slope of the Black Hills and that chain of minor uplifts connecting them with the Laramie range to the south- west. The Black Hills were at one time connected with the Laramie range through the Rawhide range and a less elevated series of uplifts extending in a northeasterly direction from the latter to the southern limit of the Black Hills. Remnants of this connecting range are still to be seen in the bluff just back of Lusk, known as Silver Cliff; on Duck creek two and one-half miles a little west of north of Lusk; near the head of Old Woman creek, about six miles north of the last mentioned place; in the ridge on the east side of Sage creek, two miles below Hat Creek post-office and eight miles northeast of the locality just mentioned; in another bluff ten miles below this and on the same side of the creek, but farther to the east; and doubtless in many other places as yet unobserved. The Cera- tops beds were originally confined to the western slope of the Black Hills and of the less elevated series connecting the latter with the Rawhide range. This is conclusively shown by the absence of the Ceratops beds not only on the eastern slope of this range where they could have been removed by erosion, but in the region to the eastward where all the beds are approximately horizontal, and where, if they ever existed, remnants of them, at least, should yet be seen. The surface of the region to the east of the Black Hills and their south- western extension, as just described, is composed for the most part of Miocene deposits, with many sections showing the underlying beds. In all such exposures in this region, hun- dreds of which have been examined, the Miocene is underlaid by marine Cretaceous or older formations. In no instance have the Ceratops beds been observed east of the Black Hills or their less elevated continuation to the southwest. The Ceratops beds proper, that is, those beds containing remains of the Ceratopsidw, are known to have a surface ex- posure in that portion of Converse county embraced within their eastern and southern border, as defined above, and a line extending from that point on the latter where it passes under the overlying beds a short distance west of Lance creek, nearly due north to Weston county; 1. e. the country drained by lower Lance, Lightning, Cow, Doegie, and Buck creeks, and that portion of the Cheyenne river and its tributaries between the mouth of Lance creek and the north line of J. B. Hatcher—Ceratops Beds of Wyoming. 137 Converse county. The creeks mentioned in this paper will be found on any good map of Wyoming. Description of the Deposits. The Ceratops beds are made up of alternating sandstones, shales, and lignites, with occasional local deposits of limestones and marls. The different strata of the series are not always continuous, a stratum of sandstone giving place to one of shales and wice versa. This is especially true of the upper two-thirds of the beds. The lack of continuity in the dif- ferent strata has rendered it well nigh impossible to establish any definite horizons in the upper members of the series. All the deposits of the Ceratops beds of this region bear evidence of having been laid down in fresh-waters. Among the inver- tebrate fossils found in them, only fresh-water forms are known. ‘There is no evidence that marine or brackish-waters have ever had access to this region since the recession of the former at the close of the Fox Hills period. The sandstones largely predominate in the lower members of the beds. They are always fine-grained, massive to well- stratified, and nearly white to yellowish brown in color. They are occasionally compact and hard, but for the most part quite soft and friable. They are composed of sharp, angular grains of quartz with some clay and mica, the whole being loosely cemented together with carbonate of lime. Almost every- where in the sandstones are numerous concretions of varying size and shape. Some are almost perfect spheres and vary from the size of a marble to 18 or 20 feet in diameter. Others are from a few inches to several feet in transverse diameter and sometimes several hundred feet in length, a cross section forming a nearly perfect circle. Others still are very irregu- lar in form. These concretions usually show no concentric structure, and while they sometimes enclose foreign objects, as a Triceratops skull or a single bone as a nucleus, they are for the most part simply centers of solidification and not true con- eretions. This is frequently shown by the cross-bedding in them, so often seen in the sandstones themselves. The shales are almost entirely wanting in the lower 400 feet of the Ceratops beds, but they are well represented in the suc- ceeding series. They are quite soft and loosely compacted, composed mostly of clay with more or less sand in places. The prevailing color is dark brown, but they are sometimes red or bluish. They are well stratified and finely laminated, and contain occasional limestone concretions enclosing numer- ous invertebrates. 138 J. B. Hatcher—Ceratops Beds of Wyoming. The lignites occur in thin seams, never more than a few inches thick, of only limited extent, and with many impuri- ties. At no place in the Ceratops beds of this region have workable coal beds been found. These do occur, however, in the Ceratops beds of Montana. The best exposure of them observed there is in Fergus county, on Dog creek, about 15 miles from its mouth, just above where it enters the Bad Lands of the Missouri. Workable coal seams occur in W yom- ing, in the beds west of Lance creek, which overlie the Ceratops beds, and will be referred to later. Intercalated with the sandstones, shales, and lignites, are quite local deposits of limestones, clays, and marls. The latter are composed almost entirely of fresh-water shells, fragments of bone, teeth, ete. Along their southern and eastern border, the Ceratops beds dip to the northwest, at an angle of about 16° between Buck ereek and Lance creek. One half mile east of Lance creek, the dip is 29° to the northwest. This angle of inclination rapidly diminishes toward the interior, and is scarcely notice- able in the vicinity of Lightning, Cow, and Doegie creeks. The fold is quite abrupt as is further shown by cracks which were made in the strata at the time of disturbance at right angles to their dip and parallel with their strike. These fis- sures have been filled by infiltration with materials now harder than those forming their walls, and now appear in many places as projecting veins, from a fraction of an inch to a foot or more in width, and from a few yards to several hundred in length. . Stratigraphical Position of the Ceratops Beds. The Underlying Beds.—Along their southeastern border, especially between Lance and Buck creeks, are many fine ex- posures of the Ceratops beds and the underlying Fox Hills. Perhaps the best exposure is that made by a small tributary emptying into Buck creek, about. four miles east of Lance ereek and one-half mile northwest of the Buck creek pens used by the cattle men for round-up purposes. This water- course has here cut its way in a southeasterly direction, at right angles to the strike, down through the lower half of the Ceratops beds, through the underlying Fox Hills sandstones, and into the Ft. Pierre shales. At this place, the bed of Buck ereek and the rounded hills of that region at the head of this stream, embraced between the border of the Ceratops beds and Fox Hills sandstones on the north and _ the bluffs of Mio- cene clays and conglomerates on the south, are composed of Ft. Pierre shales. All the strata of this entire section dip to J. B. Hatcher—Ceratops Beds of Wyoming. 139 the northwest at an angle of 16°. The exposure is a continu- ous one, and commencing from below, the section is as fol- lows : At the base are the Ft. Pierre shales of unknown thickness, several hundred feet of which are exposed. They consist of argillaceous, finely laminated, dark shales, quite soft and easily eroded. They contain many limestone concretions and numer- ous invertebrates; among others are Baculites ovatus, B. com- pressus, Scaphites nodosus, Placenticeras placenta, Nautilus Dekayi, ete. Overlying the Ft. Pierre deposits is an alternating series of sandstones and shales with an estimated thickness of 500 feet. In the lower portion of this series, the shales predominate, but toward the middle the sandstones are in excess, and in the upper 50 feet they entirely replace the shales. The sandstones are of a yellowish brown color, very fine grained, firm, and well stratified below, but softer, and quite massive at the top, where they contain numerous large concretions and a rich marine invertebrate fauna. Representatives of this fauna have been sent to Mr: T. W. Stanton of the U.S. National Museum, and were pronounced by him io be characteristic of the uppermost Fox Hills in direct conformity with their strati- graphical position. The Ceratops Beds.—Next come the Ceratops beds with an estimated thickness of 3,000 feet, resting directly upon the Fox Hills series. Immediately above the Fox Hills is a very thin, but quite persistent, layer of hard sandstone, well strati- fied, and quite cleavable along the lines of stratification. This stratum of sandstone is about six inches thick, and is regarded as the dividing line between the marine and fresh-water beds. It is overlaid by about 150 feet of yellowish brown, well- stratified sandstones apparently non-fossiliferous. These are in turn overlaid by about 250 feet of almost white, fine-grained, massive sandstones with numerous concretions, but no fossils were found in them. Next comes the fossiliferous portion of the Ceratops beds, consisting, as before stated, of alternating sandstones, shales, and lignites. All the beds of the entire section are conformable, and bear evidence of a continuous deposition, from the Ft. Pierre shales up through the Fox Hills sandstones and the overlying fresh- water Ceratops beds. The It. Pierre shales are not suddenly replaced by the Fox Hills sandstones, but the transition is a gradual one, and it is impossible to say just where the one ends and the other commences. The same is true of the beds over- lying the Fox Hills. The thin seam of hard sandstone, just referred to as separating the fossil-bearing Fox Hills sand- stones below from the very similar non-fossiliferous sandstones 140 J.B. Hatcher—Ceratops Beds of Wyoming. above, is here regarded as the dividing line between the Fox Hills and Ceratops beds. But this decision, it must be admit- ted, is quite arbitrary, and the evidence in its favor is negative rather than positive. The only reason for placing the over- lying 400 feet of non-fossiliferous sandstones in the fresh- water series is the absence of fossils in them, which may per- haps be accounted for by the destruction of the marine forms brought about by the change from salt to fresh-waters. The overlying non-fossiliferous beds may have been deposited in the fresh-waters before fresh-water forms had distributed them- selves over this region. The sandstones of the entire series are very similar, and since there is entire conformity through- out, it is absolutely impossible to determine just where the marine beds end and the fresh-water beds commence. The Ceratops beds of this region are a natural sequence of the Fox Hills. The materials composing both were evidently derived from a common source. The only safe criteria for distinguish- ing one from the other are their fossils. “The Over lying Beds.— Along their eastern border, the Cera- tops beds are occasionally unconfor mably overlaid by Miocene clays and conglomerate. But these deposits, if they ever extended over any considerable portion of the region now occupied by the Ceratops beds, have been almost entirely removed by erosion. To the west of Lance creek, the Cera- tops beds pass under a very similar series of sandstones, shales, and lignites, of about the same thickness, and Confonmanle with them. In this series, the sandstones are more massive than the underlying sandstones; the shales contain more sand ; and the lignites are more frequent, of a better quality, and attain a oreater thickness, as shown at the Shawnee coal-mine on Shawnee creek, where a single bed of coal is 10 feet thick, and of a quality sufficiently good to enable it to be profitably mined for commercial purposes. Thus far no vertebrate or invertebrate fossils have been found in these beds, but they contain a rich fossil flora, representatives of which have been sent to Prof. F. H. Knowlton of the National Museum, with a request for his opinion as to the age of the beds, based upon the evidence afforded by the fossils. Upon no other evidence than a general similarity to known Laramie deposits in other regions, they are here regarded as Upper Laramie. Age of the Ceratops Beds. In a series of articles commencing in the April number of this Journal for 1889, Prof. Marsh has referred the Ceratops beds to the Laramie, mainly upon evidence afforded by their ver- tebrate fossils. Owing to the fact that very few vertebrates J. B. Hatcher—Ceratops Beds of Wyoming. 141 had previously been described from the typical Laramie, «as first defined by Mr. Clarence King, and the consequent lack of vertebrate forms known to have come from the Laramie for comparison with those found in the Ceratops beds, it must be admitted that the vertebrate fauna of the latter is, in itself, at present not sufficient proof to establish the Laramie age of the Ceratops beds. Fortunately the Ceratops beds contain an extensive inverte- brate fauna, in which Dr. C. E. Beecher has identified the following: Unio Couesii, White, Spherium jformosum, M. & H., Linnea compactilis, Meek, Campeloma multilineata, M. & H., Zulotoma Thompsoni, White, and others known from the typical Laramie, some of which are characteristic of it. The invertebrate fossils may, therefore, be considered as additional evidence of the Laramie age of the beds. But the most conclusive evidence that the Ceratops beds belong to the Laramie period is that afforded by their actual position in regard to the Fox Hills. As stated above, they conformably overlie the Fox Hills, which is the normal posi- tion of the Laramie. This conformability must be regarded as an actual and not an apparent one, since it is shown in an almost continuous exposure for many miles along the south- eastern border of the beds, where they are upturned at an angle of from 16° to 29°, and where an unconformability, if any existed, would be plainly visible. The evidences in favor of referring the Ceratops beds to the Laramie are: (1) They conformably overlie the Fox Hills sandstones and contain both a reptilian and a mammalian fauna, with decided Mesozoic affinities. Among the reptiles, the Dinosaurs are, in degree of development and point of numbers both as to indi- viduals, and genera and species represented, probably unsur- passed in any previous smilar division of the Mesozoic ; while as regards degree of specialization, they are superior to all previous forms. This age was preéminently an age of reptiles. (2) They contain an invertebrate fauna comprising many forms identical with those already described from the typical — Laramie, some of which are unknown except in the Laramie. (3) They immediately and contformably overlie the Fox Hills, and show evidence of a continuous deposition through both series. Probable Conditions attending the Deposition of the Ceratops Beds. The change from marine to fresh-waters which took place at the close of the Fox Hills and the beginning of the Laramie was brought about by the great continental elevation going on 142 J. LB. Hatcher—Ceratops Beds of Wyoming. in previous Cretaceous periods, and sufficient to cause a reces- sion of the salt waters at the close of the Fox Hills. During the Laramie, this region was occupied by fresh-waters or in places by dry land. This period of elevation which brought about the close of the marine Cretaceous is thought to have been followed by a period of subsidence during the Laramie. For, since the beds of the Laramie were evidently deposited in shallow waters, as is abundantly shown by the great number of lignite seams which they contain, and still further in the Ceratops beds, at least, by the absence of continuity of strata, frequent cross- bedding, ete., it is impossible to account for so great a thick- ness of beds, all bearing evidence of having been deposited in shallow waters, except on the theory of a subsidence going on over the region during the period in which they were laid down. This subsidence must have been so gradual that the upbuilding by sedimentation at the bottom of the waters kept pace with the subsidence; any increase in the rate of the latter increasing the depth of the waters, and a decrease in the rate of subsidence causing a decrease in eon. The latter would bring about a condition requisite for the deposition and preservation of vegetable matter which would be transformed later into lignites. The Ceratops beds are thought to afford evidence in them: selves of having been deposited not in a great open lake, but in a vast swamp, with occasional stretches of open w aters, the whole presenting an aoe ee similar to that which now exists in the interior of the Everglades of Florida. This con- dition would account for the frequent changes from one mate- rial to another in the same horizon, before referred to. In some places in the beds, these changes are quite frequent, strata of sandstones and shales replacing one another in great confusion. It would also explain the cross-bedding so often seen in the sandstones of this region, in localities remote from the present border of the beds, and hence far removed from the shore of the ancient lake or swamp. ‘This cross-bedding could hardly occur in off-shore deposits of a great fresh-water lake of any considerable depth. The conditions that prevailed over this region during the period in which the Ceratops beds were deposited were prob- ably those of a great swamp with numerous small open bodies of water connected by a network of water courses constantly changing their channels. The intervening spaces were but slightly elevated above water level or at times submerged. The entire region where the waters were not too deep was covered by an ‘abundant vegetation, and inhabited by the huge Dinosaurs (Zriceratops, Torosaurus, Claosaurus, ete.), as well J. B. Hatcher—Ceratops Beds of Wyoming. 143 as by the smaller crocodiles and turtles, and the diminutive mammals, all of whose remains are now found imbedded in the deposits. That these animals at one time inhabited the very region where they now lie entombed is conclusively shown by the occasional finding of entire skeletons with every bone in place, at localities far distant from the border of the beds, and in a state of preservation which could not possibly exist had they lived and died on a distant shore, and their car- casses been transported by the waters to their present resting places after death. Moreover, skeletons are sometimes found in an upright position or inclined to one side or the other, showing that the individual met death by miring in the imme- diate spot where the remains now rest. A noteworthy exam- ple of this was that of the skeleton of a Dinosaur discovered in August, 1891, by Mr. A. L. Sullins, and recently described by Prof. Marsh as Claosawrus annectens.*. This skeleton when found was in a partially erect position, the limbs ex- tended, and every bone in its natural position except where exposed and worn away by recent weathering. The ribs were still distended, retaining the exact form and capacity of the thoracic and abdominal cavities. The whole showed that the animal in its wanderings had mired in the quicksands, and in its struggles for liberation had been engulfed by them. In the sandstones of the Ceratops beds hardly a fossil bone of any considerable size is to be found that does not bear evi- dence of having been dropped in shallow waters. In many instances, it is still possible to determine the direction of the eurrents which succeeded in burying the bones, and thus pre- vented their decay. For instance, on one side of a bone the matrix will be made up entirely of sand, while on the oppo- site side the stems and leaves of plants have been dropped, and, now partially lignitized, form a considerable portion of the matrix. This arrangement of the materials of the matrix in which the bone is imbedded shows the direction of the current to have been from that side containing only sand, and toward the side containing the plants. So shallow were the waters, the bone itself became an obstacle sufficient to pro- duce an eddy on its lower side, in which the leaves and other vegetable materials accumulated, and sank to the bottom. Conclusions. If the Ceratops beds of Converse county, Wyoming, are the equivalents of the typjcal Laramie of southwestern Wyom- ing, the remarkable vertebrate fauna of the former will prove of great importance in determining the age of other beds now * This Journal, vol. xliii, p. 453, May, 1892; and vol. xliv, p. 171, Aug., 1892. 144 7. C. Mendenhall— Use of Planes and Knife-edges in doubt, containing like or similar faunas. Notably among the latter are the Denver and Arapahoe beds in the vicinity of Denver, Colorado, and their probable equivalents in other portions of the same state, recently described by Mr. Whitman Cross, as “ The Post Laramie Deposits of Colorado.”* Mr. Cross refers these beds to a period later than the Laramie on account of unconformities existing, in some places, at least, between them and the underlying recognized Laramie and older Cretaceous formations, and in opposition to the evidence afforded by the vertebrate fossils thus far obtained in them. Whether it is better to ignore the evidence afforded by the vertebrate fossils, or to treat these unconformities as local, remains to be decided by future investigations. It is quite possible that Dinosaurs continued into the early Eocene, but they were represented there, if at all, only by degenerate types, and less: specialized forms. It would certainly be remarkable, not to say impossible, that a group of Dinosaurs showing so great a development and marked specialization as are to be seen in Z7riceratops and Claosaurus should continue uninterruptedly from near the base of the Laramie up into the Tertiary. Nevertheless at least two species of Zrzceratops have been described from the Denver beds referred by Mr. Cross to the Post-Laramie. Regions affording such contra- dictory evidences should be thoroughly examined, and, where possible, their actual stratigraphical relations should be deter- mined. Results thus attained might be sufficient to harmonize observations now in apparent opposition. Yale Museum, New Haven, Conn., December 5, 1852. Art. XVIII.—On the Use of Planes and Knife-edges in Pendulums for Gravity Measurements ;+ by T. C. MENDENHALL. In the theoretical discussion of the pendulum it is usual to assume that it vibrates about an axis which is a straight line. — In practice it is generally attempted to realize this condition as nearly as possible and the method almost if not quite uni- versally adopted has been to attach what is technically known as a knife-edge to the pendulum and allow it to rest upon a suitably supported plane horizontal surface. The axis about which rotation takes place is at any moment determined by the contact of the edge with the plane surface. To satisfy theoretical conditions it is evident that this edge must be * This Journal, vol. xliv, p. 19, July. 1892. + Read at the meeting of the National Academy of Sciences, Nov. 3, 1892. in Pendulums for Gravity Measurements. 145 formed by the intersection of two perfectly plane surfaces, a condition which can never be quite realized in practice. It is important, therefore, to inquire how it may be most nearly approached and especially by what disposition of parts, both as to form and arrangement, a given departure from it will pro- duce the minimum effect upon the period of the pendulum and upon the value of the force of gravity obtained by its use. What is believed to be an important departure from the universal practice in regard to the arrangement of parts has recently been experimentally investigated and with very satis- factory results. It consists in an exchange in place of the knife-edge and plane, the latter being attached to the pendu- Jum and the former to the fixed support. This arrangement offers many advantages to which it is desirable to invite atten- tion. It will be best, however, to refer in the beginning to what will at once suggest itself to many as a serious objection to this plan. When the knife-edge is attached to the pendu- lum it may be assumed to have a constant relation to its mass, at least so long as the pendulum does not suffer an injury which alters its configuration. The axis about whieh vibra- tion takes place may therefore be regarded as constant as far as relates to different sets of swings, and it will be prac- tically indifferent as to what part of the supporting plane it rests upon. When the plane is attached to the pendulum this axis of vibration is entirely determined by the position of the plane upon the knife-edge. This difficulty, which at first sight appears to be formidable. readily disappears in practice. In fact, a little calculation will show that the line of contact between the knife-edge and the plane must vary in position by a relatively large amount in order to effect sensibly the period of the pendulum. Even if the placing of the pendulum for successive swings were accom- plished by no more accurate devices than the eye and hand, it would not be difficult to avoid sensible error from this source. The apparatus by means of which the pendulum is lifted from and lowered upon the knife-edge is readily made adjustable so that any desired line of contact can be secured and retained indefinitely. As an illustration of the constancy of period of a pendulum arranged in this way, as well as showing the ease and accuracy with which the period of vibration is ascertained, the follow- ing results are exhibited. They show the period of the pendulum derived from indi- vidual swings extending through about an hour each. Twelve such swings were distributed nearly uniformly through a period of twenty-four hours, in order to eliminate any effect of irregular hourly rate of the chronometer. The figures as 146 Z. C. Mendenhall— Use of Planes and Knife-edges shown below include this effect, of course, it being eliminated only from their mean. The two sets shown were made for the purpose of determin- ing a “pressure coefficient,’ the first being made in air at a pressure of 257" and the second at a pressure of 600". It will be seen that in no ease does the variation from the mean amount to as much as one part in a million, a constancy which leaves little to be desired. Pres) /25™m" Press 0. 0mm Period vy. Period y. 5006904 — 4 50073868 + 4 901 — 1 D “74 —2 898 + 2 7i + 1 900 O 73 — 1 902 — 2 72 () 899 + 1 75 —3 901 — 1 73. —1 898 + 2 71+ 1 896 + 4 70 + 2 902 — 2 68 + 4 899 + 1 69 + 3 900 0 75 — 3 Mean °5006900 Mean °5007372 The advantages of the new form of pendulum will be made evident on an examination of its application to the differential method or use of a so-called invariable pendulum as well as to the reversible form for absolute determinations of gravity. There is an advantage in the matter of construction. It is not easy to insert the knife-edge in the head of the pendulum so that it shall be at right angles to the axis of symmetry of mass. The plane used in its stead may be accurately adjusted by simple optical methods. The advantage of the plane in the matter of permanency or invariability is so evident as hardly to need remark. The knife-edge is usually the most delicate part of a pendulum, that most liable to be injured and generally incapable of being repaired when once damaged. In an invariable pendulum the knife-edge cannot be reground or replaced by another, with- out destroying the identity of the whole so that swings at different places or times are no longer comparable with each other. A pendulum carrying a plane instead of a knife-edge is evidently vastly less liable to accidental injury and is enti- tled in a much greater degree to the name “invariable.” The knife-edge being no longer an integral part of the vibrat- ing mass can be reground or replaced at will. In fact in prac- tice it is desirable to have several knife-edges and in an exten- sive pendulum campaign a “standard edge” will be used in Pendulums for Gravity Measurements. 147 upon which swings will only rarely be made in order to detect any deterioration which may take place in those in daily use. Knife-edges of different material may also be used if such a course is found to be desirable. In the reversible pendulum for absolute measures, in addi- tion to the advantages already described there is also the very important fact that the measurement of the length of the pendulum is likely to be more accurate. Whether the knife- edge is a part of the pendulum or of the fixed support, a certain amount of elastic compression will always take place when the weight of the pendulum is upon it and this is likely to be relatively greater the more perfect the edge. If the knife-edge is a part of the pendulum the length of the latter must be greater when vibrating than when ‘at rest and sup- ported with the edge free for length measurement. The measurement of the distance between the two knife- edges of a reversible pendulum as ordinarily made is a matter of much difficulty. It is believed that without resorting to extraordinary methods the distance between the two planes of the newly constructed reversible pendulum will be capable of measurement with higher accuracy and if necessary or desira- ble, recourse may be had to the method of Michelson and Morley for relating the distance between surfaces to the length of light waves, Perhaps the most important gain thus far from the new arrangement is that it has made it possible to investigate the knife-edge, as to form and material, with an ease and thorough- ness hitherto unattainable. As long as the knife-edge forms a part of the pendulum it is impossible to study the effects of variation in its angle, width or material because every such alteration must necessarily alter the vibration-period by chang- ing the mass and form. With the new form this difficulty no longer exists; the vibrating body remains constant in mass and configuration and any change in its period is due to the influence of the knife-edge. Some of the results already obtained are of sufficient interest to justify their publication in advance of a full and complete investigation now in progress. In order to investigate the effect of a wearing or slight flattening of the edge, such as may, and in fact does result from long and not too careful use, a steel knife-edge was used, the plane, forming a part of the pendulum, being of agate. A steel edge was used on account of the greater ease with which it could be manipulated in grinding. The agate knife-edge has been in general use, but experiment showed that both steel and agate being made as perfect as possible, the vibration periods were essentially the same. The angle which the two 148 7. OC. Mendenhall— Use of Planes and Knife-edges planes forming the edge made with each other was 110°. The edge was first ground until it was pronounced as perfect as was practicable by the artist, Mr. E. G. Fischer, chief mechanician of the Coast and Geodetic Survey, who has shown rare inge- nuity and skill in the solution of the mechanical problems arising during the investigation. The width of the edge was then measured, using a microscope magnifying from 100 to 500 times. This was a difficult operation, the question of illumination being troublesome. It seemed tolerably certain, however, that the width of such an edge was not greater than 1” (-001"™") Several different edges ground in this way were measured with essentially the same result. After the vibra- tion period on one of these had been ascertained it was given one or two light touches upon the stone, producing an edge which was found on measurement to be approximately 2” in width. After the pendulum had been swung on it it was still further flattened. Theory shows that a pendulum will vibrate more rapidly upon a slightly flattened or rounded edge than upon one. which is perfect. The table below shows the results of experiment conducted as above described. The pendulum used was one of the short, approximately half-second, pendulums of the form referred to a year ago.* The numbers showing the width of the knife-edge must be regarded as approximations only but they are pr obably relatively not far from correct. They indicate very clearly and positively the important part played by the knife-edge and the importance of having it per- fectly ground. There is good reason to believe that this mat- ter has not hitherto received that attention in pendulum researches which it is here shown to demand. While the effect of a given amount of flattening on the vibration-period would be less with a long seconds pendulum than with one of shorter period, the tendency towards flattening, arising out of greater weight and greater difficulty of handling would be very much “increased. There is no doubt that in some imn- portant gravity operations knife-edges have been used which, in the light of these results must be considered intolerably poor. It will be observed that going from what may be accepted as a practically perfect edge to one only one two- hundredth of a millimeter wide, changes the period by one part in forty thousand, an amount entirely outside of a reason- able limit of accuracy for work of this kind. The question of the best angle for the knife-edge is also important and interesting. If the material of which the edge is composed were physically perfect and if the faces were perfect planes all angles, within certain wide limits, would be * This Journal, February, 1892. in Pendulums for Gravity Measurements. 149 equally good. Imperfection of substance, as to strength, con- tinuity, ete., is the principal difficulty and this is met by mak- ing the angle of the faces as great as possible. But the errors arising from the impossibility of grinding the faces to true planes are reduced to a minimum by making the angle as small as possible and hence there is indicated an angle neither very large nor very small which is better than others. In other words, if the angle is too small the edge will be entirely erushed and thus broadened and made imperfect. If the faces are not perfect planes it is clear that the larger the angle the wider will be the limits of the horizontal projection of the line of their intersection and this will be equivalent to widen- ing the edge upon which the pendulum swings. It is interesting that this seems to be verified in practice, as is shown in the results given below. Edges ground to five different angles, varying from 90° to 160° were used. The results show that while there is no great difference in the results with the range of angles examined, it is tolerably cer- tain that the angle should not (with this ‘material—steel) be less than 110° nor more than 140°. An angle of 130° will probably be found the most satisfactory, combining the neces- sary sharpness (when properly ground) with strength to resist accidental injury or excessive elastic compression. Steel Knife-Kdge. Width. Period. Gain. - il “5008880 0) 2 8839 41 5 8756 Dat 6°5 8508 377 10 7626 1254 Period. 5008875 8880 8874 8884 150 C. Barus—Oolors of cloudy condensation. Steel knife-edges have been very generally used in pendu- lum work but they are inferior to those made of agate. The brittleness of the latter is rather an advantage than otherwise. When an agate knife-edge receives a blow sufficient to injure it, a piece is “chipped out, ‘Jeaving the remaining portion of the edge clean and perfect as before and the only effect on the vibratory period is that due to the removal of the matter lost. Under the same circumstances an edge of steel will be flat- tened or distorted and while there may be no loss of matter the edge may be made so imperfect that the period will be decidedly affected. The grinding of an agate edge demands much more labor and skill than is required i in the preparation of one of steel but it is well worth the additional cost. It has been found that a knife-edge, even if its mass is con- siderable, is very susceptible to such distortion of figure as will render it imperfect. To avoid this it has been found de- sirable to insert the edge in a heavy tablet of brass and grind it in situ. The tablet is provided with three feet with hemi- spherical ends, resting respectively in a conical hole, a V groove and ona plane. In this way the edge is subjected to no strain after it is ground. Art. X1X.—f’reliminary note on the colors of cloudy con- densation ; by C. Barus. By allowing saturated steam to pass suddenly from a higher to a lower temperature (jet) in uniformly temperatured, uni- formly dusty air the following succession “of colors is seen by transmitted white light, if the difference of temperature in question continually increases: Faint green, faint blue, pale violet, pale violet-purple, pale purple, muddy brown-orange, straw-yellow, greenish yellow; green, blue-green, gray-blue, intense blue, indigo, intense dark violet, black (opaque) ; intense brown, intense orange, yellow, white. Seen by reflected white light, the same mass of steam is always dull neutral white. If the colors enumerated be taken in the inverse order'be- ginning with white, they are absolutely identical with the interference colors of thin plates (Newton’s rings) of the first and second order, seen by transmitted white light under normal incidence. Thus it is worth inquiring whether small globules of water, when white light is normally transmitted, affect it like thin plates. For a given homogeneous color if Hi C. Barus—Cvlors of cloudy condensation. 151 be the intensity of the incident light and #& (-04 to -05) the reflection coefficient, then after a single transmission the inter- ference maxima and minima are (1—#)’(1+4*)/ and (1—h)’ (1—k*)I; they differ only very slightly. Butif there be an in- definite number of particles all of the same size available, then this process is indefinitely repeated in such a way that while the colored light is not extinguislied, the admixed white light becomes continually more colored. Hence after a suffi- ciently great number of transmissions the emergent ray will show intense color. Seen by reflected light the case is almost the converse of this. For a single particle the masses which interfere are (k7 and k(1—z)'Z) weaker but nearly equal, and the interference is therefore very perfect. It is not, however, capable of indefinite repetition for after each interference the direction is reversed. The light which emerges in a direction opposite to the incident ray must therefore have passed through the particles, i. e. it has been brought to interference both by reflection and by transmission, and its color is thus virtually extinguished. The final point to be considered is the occurrence of black, between brown and dark violet of the first order. Here, how- ever, for relatively very small increase of the thickness of the plate, the colors run rapidly from brown through red, carmine, dark red-brown to violet. Hence these interferences are apt to occur together and an opaque effect is to be anticipated. Par- ticularly is this presumable, because the opaque field is coinci- dent with the breakdown of the steady motion* of the jet. Thus it seems that the colors of cloudy condensation may without serious error be interpreted as a case of Newton’s interferences by transmitted light. In so far as this is true one may pass at once from the color of the field to the size of the particles producing it; and the dimensions so obtained agree well with R. v. Helmholtz’s estimate made in accordance with Kelvin’s equation for the increase of vapor tension at a convex surface. In the study of the condensation phenomena vapor-liquid, the experimental power of a method, which is adapted for instantaneous observation, and which for a certain range of dimensions not only discriminate between vapor and a collection of indefinitely small suspended water globules, but actually defines their size, cannot be overestimated. An account of my work together with other allied observations will be given in the March number of the American Meteoro- logical Journal. *T refer here to Osborne Reynold’s work (Phil. Trans., III, p. 935, 1883) with liquid jets, according to which after a certain critical velocity is surpassed, the uniformly steady motion breaks up into eddying motion. I am also searching for Reynold’s lag phenomenon (I. c. p. 957). Am. Jour. Sc1.—Turirp Serius, Vou. XLV, No. 266.—FEBRUARY, 1893. 1] 152 I. A. Newton—Lines of structure in Meteorites. Art. XX.—Lines of structure in the Winnebago Co. Mete- orites and in other Meteorites; by H. A. Newron. THE ground and polished surface of a Winnebago Co. meteorite showed to me some interesting markings. Subse- quent examination revealed like markings in other meteorites. Perhaps these markings have been described. If so I have no recollection of the description, and therefore it seems worth while to call attention to them. | The polished surface of a small Winnebago stone, three or four square centimeters in area, shows several hundreds of bright metallic points. The larger iron particles in this sur- face have great varieties of shapes, —the smaller ones are usually mere points. When seen with a lens, or even at a dis- tance from the eye suited to distinet vision there does not appear to be any regular structure or arrangement of the bright points. But if the surface is so held as to be a little beyond the place of distinct vision, and at the same time, turned around in such way as to reflect always a strong light to the eye, either skylight or lamplight, there appear lines of points across the polished surface of the stone, which suggest very strongly the Widmanstaetten figures on metallic mete- orites. At times as the stone is turned no lines can be de- tected. Again one set of parallel lines or two sets crossing each other become visible. Some of the sets are very sharply manifested, and some are so faint as to leave one in doubt whether the lines are real or only fancied. There are on the surface in question six or eight of these sets of lines. - A second surface was ground nearly parallel to the first, at about one centimeter distant from it, and like lines appeared on this parallel surface. Some of the lines, but not all of them, corresponded in direction in the two surfaces. Four more surfaces approximately at right angles to the first surface, and corresponding to the faces of a right prism were then ground and upon these surfaces the like sets of lines appear with more or less distinctness, A slab of a Pultusk stone 6X7 centimeters shows over its entire surface like markings. Something like a curvature of the lines appears in one instance but in general the lines run straight from side to side of the slab. The slab is six milli- meters in thickness and most of the sets of lines have the same directions upon the two sides. A Hessle stone, a small slice from the Wold Cottage stone, one from Sierra di Chaco, one from a Sienna stone, a fragment from the Rockwood stone, and a slice from the Rensselaer Co. H. A. Ward—New Meteorite from Japan. 153 stone, all show with more or less clearness the like markings. Of three microscope slides of the Fayette Co. meteorite one shows them clearly, a second shows traces of them, the third not at all. A considerable number of the ground surfaces of meteoric stones in the Peabody Museum also show these markings. For example a triangular surface of a Weston stone, 8 or 10 centi- meters to each side, exhibits them very well. These markings are such as we might expect if the forces which determine the erystallization of the nickel-iron of the iron meteorites also dominated the structure of the rock-like formations of the stony meteorites and the distribution therein of the iron particles. The relation of quartz crystals to the structure of graphic granite is naturally suggested by these meteorite markings. Art. XXI.—Preliminary Note of a new Meteorite from Japan; by Henry A. WARD. [Read before the Rochester Academy of Sciences, Dec. 12, 1892.] SEVERAL months ago a friend, Mr. Alan Owston, who had been traveling in the interior of the main island of Japan, told me that he had seen what he thought to be a stone meteorite in a temple in Iwate. As the result of considerable corre- spondence this specimen has been sent to me, reaching me early in December. It was accompanied by a letter in Japanese language of which the following is a translation : “This meteorite which I send you herewith fell about forty years ago, viz: in the 3d year of Ka-yei, at dawn on the 4th day of the 5th month, (13th June, 1850). It fell obliquely from the W.N.W. with a great sound like thunder, at the village of Kesen in the district of Kesen, in this Prefecture. It entered the ground five feet, and remained hot for two days. The original size was said to be about equal to 23 sho of rice. This would be about 14 cubic feet. There were ten or more pieces of it which have been distributed about in various places. (Signed) Sato Keny1, of Nota village, Iwate Prefecture.” The specimen which I have received is 6,4, ounces in weight. Its shape is an irregular triangle about 63 inches in its greatest (vertical) diameter, and about 5 inches thick (see figure). Two long patches an inch wide on either side of the mass are cov- ered with crust; the rest is broken surface, showing inner 154 fH. A. Ward—New Meteorite from Japan. structure. This crust has the usual characteristic pittings, very clearly indented, yet shallow. It is of a dull blackish brown color, with a pebbled or grained appearance. Close examination shows numerous shining metallic points, appar- ; SU, TOT Re TERS Ge. My eee we i STA we Waa eu) My. +, Kesen meteorite, two-thirds natural size. ently of iron, with reddish stains, doubtless due to the oxida- tion of these. This surface shows clear signs of fusion, but there is no flow of the melted part, which might give clue to the direction of flight of the mass. The interior shows no signs of arrangement either in planes or concentric. There are several short fine fissures or fractures from one and a half to two inches in length, some of which reach to the lower side of the surface. They are not parallel, and they were doubt- less caused by the shock of reaching the earth. One inner face however seems a little smoothed, as if prior to the break- ing off of the contiguous piece there had been a sliding of sur- Chemistry and Physics. 155 faces. This stone is eminently chondritic. There is a fine- grained paste, and through it are distributed little rounded grains. Both the matrix and the grains are of the same mate- rial_—the minerals olivene and enstatite. This is all that is visible to the naked eye. But an ordinary low power lens shows many bright, metallic points. Also glossy, waxy pim- ples of red color, perhaps an effusion of chloride of iron. Some larger blotches of iron rust occur here and there. In determining the metallic portion of the meteorite (which has been done by Mr. John M. Davison of the Reynolds Labora- tory of the University of Nochester), pieces of the mass were finely crushed and the metal separated by the magnet, washed in alcohol and dried rapidly. Its weight having been taken, it was dissolved in nitric acid, and a little insoluble stony matter was separated, weighed and deducted from it. A mean of two determinations made in this way gave the metallic propor- tion about 16 per cent of the whole mass. _ This is an unusual per cent of metal,—much more than in the Waconda, which stone resembles in some respects the Kesen,—which we now name this new meteorite from Japan. We are expecting to soon receive some other pieces, which may give new facts; and also a fuller examination of the mineral constituents—metallic and non-metallic,—will be made ere long. SCIENTIFIC INTELLIGENCE. I. CHEMISTRY AND PHysiIcs. 1. On the Re-conversion of Heat into Chemical Energy in the production of Gas.—As is well known, the reaction H,O(liquid) +C =H,+CO is endothermic, the production of water gas from steam and ignited coke absorbing 38770 calories. On the other hand, the reaction C+O = CO is exothermic, the production of generator gas by passing air over excess of ignited coke evolving 29690 calories; the nitrogen being left in the gas. This amount of heat would raise the temperature of the carbon monoxide to 2169°; so that if used at once, the 29690 calories would be util- ized. But in general the gas is stored in a holder before use and so is cooled to 15°; thus losing the heat of formation, which is 30°4 per cent of the total heat of combustion of the coke. In order to avoid this loss of energy, NauMANN has suggested com- bining an exothermic with an endothermic reaction and thus stor- ing up the heat energy in the gas itself in the form of chemical energy. This may be done (1) by mixing air and water-vapor together in sach proportion that by their mutual action upon 156 Serentizic Intelligence. ignited coke, neither absorption nor evolution of heat will take place; producing a water generator gas, as in the Dowson process. Or (2) by mixing the air with carbon dioxide before passing 1t over the ignited coke; the reaction CO,+C=(CO), being endothermic, 38270 calories being absorbed, and the result- ing product being a carbon-dioxide generator gas. The author gives the composition of gases thus prepared, and compares them together, with respect (A) to the heat of combustion of one liter of the gas, calculated from composition, (B) to the calorific intensity, so calculated, and (C) to the specific heat of the com- bustion-products of the gas; 1. e. the heat evolved by one liter of these combustion products when cooled 1°. These results are as follows: Gas. A. 1B}, Ce 1. Generator gas Be Se eee ee ee ee pee 1044 cal. 1904° 0°5487 cal. Ze Carbon-dloxideycasrs sees sae obser ee INS OR ey e244: O Ogio 3. Water BeDEIALO! gas (liquid water at 15°) NG a2 e235 Oro On OMG was 4, et fo \(water-vapor ati lib")! 1790) 243 sO Gome Sei Wialtenicase meee ar cere eee eee Ria oe 282 So 283.0 20299 54a — Ber. Berl. Chem. Ges., xxv, 556; J. Chem. Soc., \xii, 673, June, 1892. G. F. B. 2. On the Temperature of Ignition of Electrolytic Gas.—More than a year ago Krause and V. Meyer showed that electrolytic as, Slowly passed through a glass tube immersed in boiling stan- nous chloride, at 606°, does not explode. FRryERand V. MEYER have now repeated this experiment using other liquids of higher boiling points. The bath was of sheet iron, in the form of a cru- cible, and was 10 cm. high and 6 cm. in diameter. Through the cover passed a sheet-iron tube 2 cm. in diameter closed at its lower end and extending nearly to the bottom of the vessel. Out- side this tube was half a kilogram of zine chloride. Within the tube a cylindrical glass bulb was placed, connected by capillary tubes with the gas-evolution apparatus and with a water trough. The zine chloride was heated to boiling, the temperature rising “to redness. On passing the electrolytic gas through the bulb, explo- sion took place at once, and this, whether the gas was moist or dry. By means of an air thermometer constructed of platinum, the temperature of the boiling zine chloride was fixed at 730°. The experiment was then repeated with zinc bromide and it was found that the explosion did not take place in actively boiling zinc bromide, the boiling point of which was found to be 650°. Hence the ignition point of e'ectrolytic gas lies between 650° and 730°. The authors observed that the explosion in the zine chlo- ride takes place with certainty only when the gas is introduced into the chloride in active ebullition. If it be passed through be- low the boiling point and then the temperature be raised to 730°, a slow union takes place, forming water.— Ber. Berl. Chem. Ges., xxv, 622; J. Chem. Soc., )xii, 680, June, 1892. G. F. B. 3. On the Electromotive Activity of the Ions.—In 1890, Nernst . and Planck deduced the electromotive forces between liquids Chemistry and Physics. 157 from the osmotic pressure and dissociation hypothesis. NERNst and Pautr have now determined experimentally the electromo- tive forces produced in liquid cells made by the combination of decinormal and centinormal solutions of potassium chloride and hydrogen chloride and have compared their results with those obtained from theory in 1890. The agreement between theory and observation is quite satisfactory. Consequently it follows that, since solutions of zine sulphate and of copper sulphate hav- ing equal molecular concentrations, are both very nearly disso- ciated into ions, there should be no considerable electromotive force at their surface of contact. Now on investigating the com- bination He | HeSO, | 1/10n CuSO, | 1/10n ZnSO, | HgSO, | He the authors have found that in fact the electromotive force devel- oped is only :00024 volt. Hence the contact of the two liquids in a Daniell cell is not the seat of an appreciable electromotive force. —Ann. Phys. Chem., U, xlv, 353; J. Chem. Soe., xlii, 671, June, 1892. Gare. 4, On the Separation of Precipitates at the Surface bounding Electrolytes.—It was long ago observed by Faraday that if a saturated solution of magnesium sulphate be placed in the bend of a U-tube and a layer of water be placed in each limb of the tube resting upon the sulphate, so that the two liquids do not mix, then on passing a current through the whole, a precipitation of magnesium hydroxide takes place at the surface which sepa- rates the sulphate from the water containing the negative elec- trode. In 1887, Herrmann repeated these experiments with zinc sulphate. WKtmmecri has now investigated the matter more thor- oughly, using in place of aqueous solutions of the metallic sul- phates, solutions prepared with sufficient gelatin so that they solidify on cooling. The presence of the gelatin does not inter- fere with the phenomenon in question while at the same time it prevents the admixture of the solution and the water, which it is not easy to prevent otherwise. Experimenting in this way, he found that of the many sulphates examined, the precipitation occurred only with those of magnesium, zinc, cadmium and alumi- num. ‘The separation of the hydroxide always takes place first, at the negative electrode itselt; the appearance of the precipitate at the boundary of the two liquids taking place later. By modi- fying suitably the method of experimenting it was ascertained that the phenomenon is due to a transfer of the solid particles from the negative electrode through the feebly conducting water by the electric current.—Ann. Phys. Chem., If, xlvi, 105; J. Chem. Soc., xlii, 1038, Sept., 1892. G. F. B. 5. On Chemical Phenomena at low Tenperatures.—PicTEr has experimented on the chemical and physical phenomena observ- able at very low temperatures. He finds that by means. of powerful compressors and aspirators, a mixture of sulphur dioxide and carbon dioxide will give a temperature of --110°, nitrogen 158 Scientific Intelbigence. monoxide and ethylene about —150°, and air a minimum temper- ature of —210° to —213°. These low temperatures were meas- ured with a dry hydrogen thermometer, or by alcohol or ether thermometers, verified by the hydrogen thermometer. The author observes that the very long radiant waves emitted at these very low temperatures pass readily through almost all bodies. Thus a vessel at —110° for example will cool with prac- tically the same rapidity whether the layer of cotton enveloping it be 50™ or 10°" or only 2™ in thickness. Moreover, he finds that when chloroform is immersed in nitrogen monoxide at —126°,a thermometer placed in it sinks to —68°5° and erystal- lization begins. If transferred to a mixture of carbon dioxide and sulphur dioxide at —80°, the thermometer falls to —80° and the crystals of chloroform melt again. Replaced in the nitrogen monoxide at —120°, the thermometer rises to —68°5° and erys- tallization begins again. At —83°5° the crystals remain station- ary increasing when the temperature falls and melting when it rises. Since crystallization takes place on the inner wall when the vessel is cooled at — 120° it seems probable that the thermom- eter in the middle is affected by the heat of crystallization and at —68°5° is in dynamic equilibrium with the medium in which it is immersed. At —80° no crystals are formed and the thermom- eter is affected by radiation only.—C. F., exiv, 1245; J. Chem. Soc., Ixii, 1138, October, 1892. Gian BP! 6. The new Telephotographic lens.—This invention of T. R. DALLMEYER makes it possible to obtain large pictures of objects situated at long distances by short exposures. The anterior element of his combination of lenses is a positive lens of large aperture and short focus, while the posterior is a negative and of fractional part of the focal length of the former lens. One is reminded of the principle of the Galilean telescope, with this difference, that the emergent rays are convergent and not diver- gent. The size of an image thrown on a screen can be varied at will by altering the distance between the elements. The farther the lens is from the focussing screen the longer will be the time of exposure. Some pictures taken by this lens were exhibited at a meeting of the Camera Club in London. One picture represented a building at a distance of 500 yards. The telephotographic lens, with 30 inches extension, represented the house as 6¢ inches long, while a rapid rectilinear lens, with extension of 14 inches, gave the house as # inch long.—WVature, p. 161, Dec. 15, 1892. Ae. SE 7. Oxygen for lime light—The oxygen gas obtained from atmospheric air by what is known as the Brin process, gives on an average a purity of 95 per cent oxygen. T. C. HepwortH in a letter to Vuture, has compared the performance of this gas in a lime light with an impure gas containing only 60°6 per cent oxy- gen. The light afforded by the impure oxygen was about one- half as intense as the light given by the purer oxygen. With the good oxygen the lime cylinder was quickly fitted, while with Geology and Natural History. 159 the other it showed no signs of destruction.— Nature, p. 177, Dee. 22, 1892. Jes 8. Interference of Electric Waves.—A Ruhmkorf coil was made to vibrate 130 times per second by means of a thermopile. To one of its terminals was attached a copper wire ending in a hook, to which a linen thread soaked in calcium chloride was attached by one end, the other hanging free. One of the terminals of a telephone was placed in contact with the thread, the other being isolated. The sound in a telephone was completely extinguished at a certain distance from the copper. When both ends of the thread (which was 3™ long), were connected by fine copper wires, two points of extinction were reached, one from each end. On shortening the thread these points approached each other and formed a zone of extinction between them. This zone of extinc- tiou spread over the entire copper wire as the thread was short- ened to zero. The neutral zone is due to interference of two waves of the same period and of equal potential meeting in opposite directions.— Comptes Kendus, Nov. 14, 1892, Nature, Nov. 24, 1892. J. 2: Explanation of Hal’s phenomenon.—E. LommMet in a pre- liminary notice, states that by means of a suitably strong current, magnetic filings sprinkled upon a conducting plate will arrange themselves so as to form a beautiful representation of the equi- potential lines of the current. When this conducting plate is brought into a magnetic field these magnetic force lines alter in length and the stream lines of the current, perpendicular to the magnetic force lines, also change, and in these changes can be found an explanation of the Hall phenomenon.—Ann. der Physik, No, 12, 1892, p. 766. IE. 10. A Mer cury Voltaic arc.—H. Avon has succeeded in pro- ducing a mercury vapor light, of great intensity, by suitably inclining a column of mercury held in a 2 shaped tube which is connected at its point of greatest curvature with a straight tube which is provided with a T-shaped connection, which allows con- nections to a manometer and to an air pump. When the column of mercury in the inverted U-tube is caused to separate at its bending by a slight shock a Voltaic are results at this point which fills the whole section of the tube with an extraordinarily intense light. Avon gives a list of the spectrum lines which he has measured by means of this light. In addition to the thirteen lines measured by Kayser and Runge, he finds twenty more. Proceedings of the Physical Society of Berlin, Oct. 21, 1892, Ann. der Physik und Chem., No. 12, 1892, p. 767. ae, av, Il. GkroLtogy AND NaTuRAL Hisrory. 1. North American Fossil Mammals.—V olume tv, of the Bul- Jetin of the American Museum of Natural History, just completed, contains the following important papers on Fossil Mammals :— Fossil Mammals of the Wasatch and Wind [iver beds, (collec- tion of 1891), by H. F. Osporn and J. L. Worrman, cov ering 68 160 Scientific Intelligence. pages.—The paper contains valuable notes on several of the species of these beds. The facts with regard to the Creodont, Paleonictis occidentalis are illustrated by a large plate showing the jaws and teeth; and figures of the dentition of Pachyzna and other genera are contained in the text. Coryphodon is described as being plantigrade behind while digitigrade in the forefeet, and figures are given. The skull of Systemodon tapirinus is repre- sented. These are a few of the many points brought out. Revision of the Species of Coryphodon, by CHaRrtes HaRyeE. For the preparation of this paper Mr. Earle had access to the collections of the American Museum of Natural History, and the collection of Coryphodon remains of Prof. Cope which was libe- rally placed at the author’s disposal. The number of species which had previously been described is twenty-one, seven of these under the genus Coryphodon, ten under Bathmodon, two pertaining to Metalophodon, and one to each Manteodon and Ectacodon. All were described by Cope except one species of Coryphodon, C. hamatus of Marsh. The study of the specimens by Mr. Earle has led him to reduce the number of species to ten ; Coryphodon radians, C. testis, C. elephantopus, C. cuspidatus, C. hamatus, C. obliquus, CU. curvicristis, C. anax, Manteodon subquadratus and Ectacodon cinctus. He expresses doubt with regard to C. hamatus, as he had not seen the specimen. Characters of Protoceras (Marsh), the new Artiodactyl from the Lower Miocene, by H. F. Ossorn and J. L. Wortman.—The specimens of this horned Artiodactyl belong to the species P. celer of Marsh. The collections of Prof. Marsh include a female skull, and those of the American Museum a male. Both are here described and figured, and also the bones of the fore and hind feet. The Protoceras celer was made the type of a new family by Marsh; and this view is sustained by the authors. They place the family between the Tragulina and the Pecora. From the latter they are widely different, having no marked affinities in the direction of either of the families, the Giraftide, Cervidee or Bovide. From the former the divergence is less great, but instead of having no horns, they have multiple horns, there being paired bony protuberances on the parietals, frontals and maxillaries, besides having several other important points of difference. The number of these bony protuberances on the cranium is ten. These protuberances however are not horn-cores, but had a dermal covering. ‘‘The grotesque appearance is heightened by the large canines, which give the lateral aspect of the skull a decided suggestion of resemblance to that of the Uintatherium.” The Proceedings of the Academy of Natural Sciences of Phila- delphbia for August, 1892, contains (pp. 291-323) a “ Revision of the North American Creodontu” by W. B. Scorr, with notes on some genera which have been referred to that group, based” chiefly on the large collection of Professor Cope. The following provisional families are described: Oxyclenide, Arctocyonide, Geology and Natural History. 161 Triisodontidx, Mesonychidx, Proviverride, Hyzenodontide, Pale- onictide, Miacide ; and then notes follow on the genera referred to these groups. The same volume of the Proceedings of the Academy (p. 326) contains a note by Prof. Cope on the discovery of remains of Hycena and other Carnivores in the Pliocene Blanco beds on the Liano Estacado in western Texas. The Hyzena—the first found in America—is named the Borophagus diversidens. One of the other Carnivores, is a Weasel, and is named by Prof. Cope Canimartes Cumminsii, after its discoverer; and a third, Felis fillianus, after Prof. R. T. Hill. Memoir on the Genus Puleosyops of Leidy and its allies, by CHARLES EarLe. pp. 267-388, 4to, of the Journal of the Acad- emy of Natural Sciences of Philadelphia, vol. ix (Oct., 1892).— This able monograph on the genus Palcwosyops, 120 pages in length and illustrated by five plates, is based on the study of the collections of the Philadelphia Academy, those of Prof. Cope, others of the Princeton Museum, and specimens in the Yale Col- lege Museum. The Princeton collections, obtained in four expe- ditions to the region under the leadership of Professors Scott and Osborn, are especially large, and have enabled the author to add to bis many excellent illustrations a restoration of Leidy’s Paleosyops paludosus. With regard to the relations ot the genus, he says: “I think that Palwosyops and the allied genera, Diplacodon, and Titanotherium, should be placed in “the family Titanotheriide.” As the prefatory remarks state, “ the association of the renowned name of Dr. Joseph Leidy with this genus gives to these investigations especial interest at the present time.” 2. Geology of the Hureka District, by ARNoLD Haauer. 396 pp. to, with 8 plates and a folio Atlas of 13 plates. Volume XX, of the Memoirs of the U. 8. Geological Survey.—This volume, besides treating of the general geology and ores of the Eureka region, discusses at length the nature and origin of its igneous rocks. The system of flexures and faults in the rocks is referred to time after the Carboniferous and before the close of the Jurassic period. No Mesozoic rocks occur in the region. The igneous rocks are termed volcanic; but no volcanoes are reported ; instead, the eruptions were along the old faults of the region, and through fissures made at the time of the eruptions. The ejection of the andesites and rhyclites was followed by the deposition of the ores, and the latter are stated to have come up from below as the result of solfataric action which accompanied the igneous action, but as having become more or less changed into different kinds, and distributed by the prolonged continuance of this action. The final conclusions of the author as to the relations and origin of the igneous rocks, are presented in a closing summary as fol- lows (p. 289). The Eureka District presents a most instructive voleanic region standing quite apart from all other centers of similar eruption, yet, in the nature of its extravasated material, typical of many localities in the Great Basin. 162 Scientific Intelligence. The region offers no direct proof of the age of volcanic energy ; yet all evidence points to the conclusion that the eruptions belong to the Tertiary era and for the most part to the Pliocene period. They may have extended well on into Quaternary time, although there is no reason to suppose that eruptions took place within historic time. : As regards their mode of occurrence the principal eruptions may be classed under four heads: First, they broke out through protound fissures along the three great meridional lines of dis- placement, the Hoosac, Pinto, and Rescue faults, and to some extent along the lesser parallel faults; second, following the lines of orographic fracture, they border and almost completely encircle cbe large uplifted masses of sedimentary strata like the Silverado and County Peak block and the depressed Carboniferous block be- tween the Hoosac and Pinto faults; third, they occur in numerous dikes penetrating the limestone; fourth, they occur in one or two relatively large bodies, notably Richmond Mountain and Pinto Peak, along lines of displacement already mentioned. All the lavas may be classed under the heads: hornblende- andesite, hornblende-mica-andesite, dacite, rhyolite, pyroxene- andesite, and basalt. They pass by insensible gradations from one to the other. All division lines are more or less arbitrary ; they are necessary for the purposes of classification, although they may not exist in nature. Field observations clearly show that the order of succession of these natural groups into which the lavas have been divided was as follows: First, that the hornblende-andesite was the earliest of all the erupted material; second, that the hornblende- mica-andesite followed the hornblende-andesite; third, that the dacite followed the hornblende-mica-andesite; fourth, that the rhyolite closely followed the dacite; fifth, that the pyroxene-ande- site succeeded the rbyolite; sixth, that the basalt was the most recent of all these volcanic products. In chemical composition this entire series of lavas shows a range in silica amounting to about 25 per cent, a range which is quite as wide as is usually found in most centers of eruption even where the volume of lavas thrown out is vastly greater and the duration of volcanic energy far longer. Analyses show endless transition products between the extreme basic and acidic lavas, with a tendency of the alkalies and silica to accumulate at the acidic end and the material forming the ferro-magnesian minerals at the basic end. It is maintained in this work that all the varied products of eruption are derived from a common source, a homogeneous molten mass. Under a process of differentiation this earlier mass split up into two magmas, designated as a feldspathic and a pyroxenic magma. The lavas at Eureka are the result of the same process of differentiation derived from one or the other of these magmas. Beginning witb hornblende-andesite, the earliest lava, the feldspathic magma became more siliceous until the close Geology and Natural Llistory. 163 of rhyolitic eruptions. The rhyolite was followed by pyroxene- andesite and the eruptions became more and more basic until the close of the volcanic period. The feldspathic and pyroxenic lavas do not approach each other ix their tenure of silica within 2°25 per cent. In chemical composition the earliest eruptions of both magmas resemble each other, but from this common ground they differentiate steadily until the feldspathic reaches the extreme acidic, and the pyroxenic the extreme basic end of their respective series. The extreme products of ditferentiation in any volcanic center in the Great Basin are rhyolite and basalt. 3. Geological Survey of Alabama, Prof. E. A. Smiru, the State Geologist, has recently issued a brief sketch of the Geology of Ala- bama, occupying 36 octavo pages. There has been published also Bulletin No. 4, of the Alabama Survey, consisting of a Report on the Geology of Northeastern Alabama and adjacent portions of Georgia and Tennessee, by C. WittaArp Hayes, Assist. Geol. U.S. G.S., which describes the rocks and the orographic structure of the region, gives figures of the flexures and faults, and closes with an excellent colored map showing the distribution of the Paleo- zoic formations from the Cambrian upward. 4. Geological Atlas of the United States, Chattanooga sheet, Tennessee.—A large folio brochure, consisting of 6 pages of text and 4 maps, has just been published by the United States Geologi- cal Survey. The maps include a topographical map of the region, two detailed geological maps in colors, and one sheet of sections. The area represented covers about 100 square miles. The size of the maps is 145 by 17} inches. The work is in the best style as regards the exhibition of the geological formations, and is also faultless esthetically. The charts are the commencement of a series, already far advanced as regards geological investigation, which has in view the representation of the geological structure of the Appalachian region. The names of the geologists men- tioned on the charts are G. K. Gilbert, Chief Geologist, Bailey Willis, Geologist-in-charge, and Geology by C. Willard Hayes. 5. The North American Continent during Cambrian Time, by C. D. Watcorr. From the 12th Report of the Director of the U. 8S. Geological Survey, for 1890-91, pp. 529-568.—Mr. Walcott here exhibits in an instructive way by maps and descrip- tions his results as to the geographical condition of Cambrian North America. 6. Lhe Lafayette Formation, by W. J. McGxr, Ibid., pp., 341-521.—This paper is a very full exhibition of the characters and distribution of the Lafayette formation. The latter subject is presented on a colored geological map, which exhibits also the author’s views as to the distribution of the Columbian formation. 7. The Origin and Nature of Soils, by N. 8. Saar, Ibid. pp. 217-346.—Professor Shaler considers the subject of soils from a geological point of view. The sources of soilsare explained, their various characteristics, the processes by which they have been formed over regions of diverse conditions, and the geological 164 Scienrsic Intelligence. agencies, living and physical, concerned in modifying them, and many fine plates illustrate the topics discussed. ‘The paper closes with observations on the action and reaction of man and the soil. 8. Cambrian Fossils of New Brunswick. — Bulletin of the Natural History Society of New Brunswick, No. X, St. John, N. B., contains a paper on Protolenus, a new genus of Cambrian Trilobites from the St. John group, by G. F. Matraew. The same genus is described by Mr. Matthew and two species figured in the Canadian Record ot Science for October, 1892. 9. Experiments in Physicul Geology.—Professor Ep. Reyer of Vienna has lately issued three interesting brochures upon subjects in physical geology. They are entitled : Ursachen der Deform- ationen und der Gebirgsbildung (pp. 40); Geologische und Geo- graphische Experimente, Heft I, Deformation und Gebirgsbildung (pp. 52); Heft If, Vulkanische und Massen-Emptionen (pp. 55, Wm. Engelmann, Leipzig.) The first named is a general state- ment of conclusions based on the experiments which are very thoroughly illustrated in the last two. The subject is treated in the form of a discussion of several hypotheses to explain mountain- making. These are: I, Changes of substance as by oxidation, hydration, solution, ete. ; II, Contraction of the earth; III, Dif- ferences of density; IV, ‘Loading or as it is termed the “ Onerar- hypothesis;” V, Hypotheses based on heat; VWI, Deformations due to eruptions. The author’s wide experience in many regions of geological disturbance and of igneous activity enables him to throw much light upon the subject treated. The numerous ex- periments were made on small models, which were compressed in the usual way with a screw. Materials of varying firmness were employed, so as to represent both stiffand yielding strata. The results of the successive steps in each experiment are liberally illustrated, so that the application to the similar cases in nature are obvious, almost without the verbal explanation. pn 1h TK 10. Brief notices of some recently described minerals.—GEIKIE- LITE and BappELEYITE are two species described by Fletcher as occurring in the form of pebbles in the gem washings near Rak- wana, Ceylon. Geikielite shows two cleavages at right angles to each other, one of them perfect. It has a splendent metallic luster and bluish black color, though thin cleavage flakes have a purplish red tint. The hardness is 6°5 and specific gravity 3°98. An analysis shows it to be a magnesium titanate, MgTiO, correspond- ing to perovskite, CaTiO,. “Baddeley ite resembles columbite in general aspect and has a specific gravity of 6:02 and hardness of 6° 5; the crystallization is probably monoclinic. In composition it is also highly interest- ing, it consisting of zirconia, ZrO,, an oxide not before found among minerals but whose existence in nature was to have oeEe anticipated. — Nature, Oct. 27, 1892. Braziutre is described by Hussak from the granular pyroxenic rock called jacupirangite at the iron mine of Jacupiranga, Brazil. Geology and Natural [listory. 165 It occurs in monoclinic crystals tabular parallel to @ (100); they are usually twins and often complex. The color is yellow to dark brown, the luster greasy to vitreous, the hardness 6°5, and the specific gravity 5-006. It is announced as a tantalo-niobate probably near to yttrotantalite, but the author (priv. contrib.) has stated later that Prof. Blomstrand finds it to consist of zirconia ; it hence is to be united with baddeleyite. (Jahrb. Min., ii, 141, 1892,). Fletcher (letter of Jan. 7) suggests that the original qualitative tests may have been made upon a different mineral, from that described crystallographically and analyzed by Blom- strand. ForceritE, BLrurirr, WuHartonirE.—Dr. Stephen H. Emmens has recently given (Jour. Amer. Chem. Soe., xiv, No. 7) the results of an examination of some nickel minerals from the Sud- bury district, Algoma, Ontario, to which the above names have been given. Folgerite occurs massive with a light bronze-yellow color and grayish black streak ; specific gravity 4:73; hardness 3°5 ; non- magnetic. One of three analysis is given below (1), the composi- tion corresponds to NiFeS, or intermediate between millerite and pentlandite. It is named after Commodore W. M. Folger of the UES Navy: Blueite occurs massive with olive-gray to bronze color, black streak, specific gravity 4:2 and hardness 3 to 3°5; it is non-mag- netic. An analysis (deducting gangue) is given under II below; in composition it is a nickeliferous pyrite with Fe: Ni= 12:1, though it differs in being easily soluble in nitric acid without separation of sulphur. It is named after Mr. Archibald Blue, now Director of the Bureau of Mines of Ontario. Whartonite occurs in cellular form with granular structure, the cavities being lined with minute cubic crystals; color bronze-yel- low, streak black; hardness 4 and specific gravity 3°73: About 10 p.c. of the fine powder was found to be magnetic and the analysis leads to the conclusion that it is a mixture of a nickel- iron disulphide with some magnetite; deducting the latter the results in ILI are obtained, corresponding to (Fe, Ni)S, with Fe: Ni =7:1. It isnamed after Mr. Joseph Wharton, of Camden, N. J. The analyses are as follows : S Fe Ni los WI OYAOUBE Beso Bete 31°10 33°70 35°20 = 100 Getto a 55:29 41°01 B97) NOY) ie Whartonite, = 52°29 41°44 6:27 = 100 To these analyses of the Sudbury nickel ores may be added those quoted in Dana’s Mineralogy (1892, pp. 65, 74, 75), also those by Hoffmann mentioned in the January number (ps 546) i: it can hardly be supposed that all of these ores are distinct homo- geneous minerals. NickEeL-SKUTTERUDITE. A gray metallic mineral of granular structure occurring in silver ore (native silver) near Silver City, 166 Scientific Intelligence. New Mexico, is described by E. Waller and A. J. Moses. It has a hardness of about 5, gray color and black streak. An analysis, after deducting 4°56 of SiO, and 8°38 silver gave the results be- low; these correspond to RAs, with R= Ni: Co: Fe=4: 2:1, or skutterudite in which the cobalt is largely replaced by nickel. As Ni Co Fe 78°67 1] 275) 6°16 | toy 11100) —School of Mines Quarteriy, vol. xiv, No. }. HavucnEcornirE is a nickel-bismuth mineral described by Scheibe from the Friedrich mine in the Hamm mining district, Germany. It occurs in tetragonal crystals and massive of a light bronze-yellow color; hardness 5, specific gravity 6:4. Analyses by R. Fischer and others gave discordant results be- cause of the want of homogeneity of the material, but the conclu- sion is reached that the composition is essentially Ni(Bi,Sb,8). —Jahrb. Preus. Geol. Landesaustalt, 1891, p. 91. CuUPROCASSITERITE.—A note upon this supposed new tin mineral from the Black Hills is given by Titus Ulke in the Transactions of the American Institute of Mining Engineers; a further critical investigation is given by Headden on p. 108 of this number. 11. Large Variations in the Metamorphosis of the. same species.—An elaborate memoir entitled, The Hmbryology and Metamorphosis of the Macroura, by W. K. Brooks and F, H. HERRICK, makes 140 pages quarto of the fifth volume of the Memoirs of the U. 8S. National Academy of Sciences, and is illustrated by 57 plates. The species microscopically investi- gated and here reported upon are of the genera Gonodactylus Alpheus and Stenopus. The authors mention, in the introductory pages, as one remarkable result of their study of the genus Alpheus, the discovery that while the larval stages of different Species are similar, the individuals of a single species sometimes differ more from each other as regards their metamorphoses than the individuals of two very distinct species, and make on this point the following remarks : This phenomenon has been observed by us and carefully studied in two species— Alpheus heterochelis and Alpheus Sauleyt —and it is described in detail, with ample illustrations, in the chapter on the metamorphosis of Alpheus. In the case of the first species the difference seems to be geographical, for while all the individuals which live in the same locality pass through the same series of larval stages, the life history of those which are found at Key West is very different from that of those which live on the coast of North Carolina, while those which we studied in the Bahama Islands present still another life history. In the case of the second species— Alpheus Saulcyi—the difference stands in direct relation to the conditions of life. The individuals of this species inhabit the tubes and chambers of two species of sponges which are often found growing on the same reef, and the metamorphosis of those which live in. one of these sponges is Geology and Natural History. 167 sometimes different from that of those which inhabit the other. In this species the adults also are different from each other, but as we found a perfect series of transitional forms there is no good reason for regarding them as specifically distinct; and in the case of the other species— Alpheus heterochelis—we were unable, after the most thorough and minute comparison, to find any difference whatever between adults from North Carolina and those from the Bahama Islands, although their life histories exhibit a most sur- prising lack of agreement. In fact, the early stages in the life of Alpheus heterochelis in the Bahama Islands differ much less from those of Alpheus minor or Alpheus Normani than they do from those of the North Carolina Alpheus heterochelis ; and, ac- cording to Packard, the Key West heterochelis presents still an- other life history. In the summer of 1881 I received the American Naturalist with Packard’s very brief abstract of his observations at Key West upon the development of Alpheus heterochelis, and read with great surprise his statement that this species has no metamor- phosis, since, while still inside the egg, it has all the essential characteristics of the adult. As I had under my microscope at Beaufort on the very day when I read his account a newly hatched larva of the same species and was engaged in making drawings to illustrate the metamorphosis of which he denies the existence, and as my experience in the study of other Crustacea had taught me that all the larve of a species at the same age are apparently facsimiles of each other down to the smallest. hair, Packard’s account seemed absolutely incredible, and I hastily decided that, inasmuch as it was without illustrations and was written from notes made many years before, it involved some serious error and was unworthy of acceptance. This hasty verdict I now believe to have been unjust, since my wider ac- quaintance with the genus has brought to my notice other instances of equally great diversity between the larve of differ- ent specimens of a single species. The phenomenon is, however, a highly remarkable one and worthy the most thorough examination, for it is a most surpris- ing departure from one of the established laws of embryology— the law that the embryonic and larval stages of animals best exhibit their fundamental affinities and general resemblances, while their specific characteristics and individual peculiarities make their appearance later. This is one of the important subjects illustrated in the follow- ing descriptions. 12. Morphologische Studien von K. Scuumann. Ite Abtheilung. —206 pp., 6 Taleln. 8vo. Leipzig, 1892 (Wm. Engelmann. )\—Prof. Karl Schumann has just published the first part of his “ Morpholo- cische Studien,” in continuance of his investigations into the anat- omy of the flower, ‘These studies will concern themselves not only with flower-structure but also with the anatomy of flowering plants in general, along the lines laid down by Hofmeister in his « Allge- meine Morphologie.” The first half of this part, therefore, is Am. Jour. Sc1.—Tuirp Series, Vou. XLV, No. 266.—FeBRuaARY, 1893. 12 168 . Scientific Intelligence. devoted to a discussion of phyllotaxy. The arrangement of leaves in spiral lines is first considered and. then the various published views upon this topic are discussed with some fullness. Schu- mann passes in review Braun’s work in establishing the study of phyllotaxy upon ascientific basis, Hofmeister’s effort tu explain the spiral arrangement by the fact that new organs are formed in the largest gaps left between organs already formed, Sch wendener’s success in demonstrating the mechanical basis for phyllotaxy, and Sachs’s theory that the spiral lines, e. g. in the Screw-Pine, are produced by torsion during the growth of the axis. He, himself, points out that the arrangement of leaves in straight or spiral ranks is intimately connected with the symmetrical or asymmetri- cal development of the sheathing bases of the leaf, which make their appearance upon the growing point of the plant before the leaves do. This relation holds true in all Monocotyledons and most Dicotyledons. In the second half, the special morphology of the genus Adoxa and of the Cohort Fluviales is discussed in support of this view. WwW. A. 8. III. MiscELLANEOUS SCIENTIFIC INTELLIGENCE. 1. Bulletin from the Laboratories of the State University of Iowa. Vol. 1, No. 2.—This number of the lowa Bulletin opens with a long paper on the Myxomycetes of Eastern Iowa by T. H. McBride, with ten beautiful plates from drawings by Miss Mary P. McBride. It also contains four important paleontological papers by 8. 8S. Calvin; a paper by B, Shimek on the identity of Pyrgula scalariformis with P. Mississippiensis, and its occur- rence, with other species, in the less of the Mississippi, but known only in the fossil state; and Notes on Karyokinesis, by L. B. Elliott. Prof. Calvin reports on fossils from the Lower Magnesian limestone of Northeastern Iowa, showing their rela- tions to those of the Calciferous of New York. 2. Astronomical Journal Prizes.—Two prizes of two hundred dollars each, in a gold medal or in money, are offered in the Astro- nomical Journal, No. 284, to be awarded to resident citizens of the United States. Details of the conditions are given in the Astr. Journal. The first will be given for the best series of determinations of the positions of comets during the year ending March 31st, 1894: —the second for the best discussion of the path of a periodic comet, the investigation to be made within the two years next preceding Sept. 1, 1894. 3. Ostwald’s . Klassiker der Eauakten Wissenschaften.—A notice of this valuable series was given in the January number of this Journal; the three following volumes have just been issued : No. 38. Photochemische Untersuchungen von R. Bunsen and H. E. Roscoe, (1855-59). Zweite Halfte. No. 39. Die in der Atmosphére vorhandenen organisirten Korperchen: Prifung der Lehre von der Urzeugung von L. Pasteur (1862). No. 40. Zwei Abhandlungen tiber die Warme von A. L. Lavoisier und P.S. DeLaplace (1780 u. 1784). AX Je se ABN ID) Ih AS Art. XXIl.—festoration of Anchisaurus, by O. C. MarsH. (With Plate VL) Tae Triassic Dinosaurs now known from the Connecticut river sandstone have been investigated by the writer, and some of the results have already been placed on record in this Journal.* Remains of five individuals have been discovered, sufficiently well preserved to indicate the main characters of the animals to which they pertained. These were all carnivo- rous forms of moderate size, and the known remains are from essentially the same ceological horizon. Many larger forms, probably herbivorous, are indicated by footprints, but no characteristic portions of the skeleton have yet been found. The genus Anchisaurus, one of the oldest known members of the Zheropoda, is so well represented by parts of four skeletons, two nearly complete, from these deposits, that a restoration of one species can now be made with considerable certainty. This has been attempted, and the result is given, one-twelfth natural size, in the accompanying plate. The animal when alive was about six feet in length. The skeleton chosen for this restoration is the type speci- men of Anchisaurus colurus, already described by the writer. This skeleton when discovered was entire, and apparently in the position in which the animal died. Portions of the neck and the tail vertebree were unfortunately lost before the importance of the specimen was realized, but the skull and nearly all the rest of the skeleton were saved. From these the matrix in great part has been removed, so that the more important characters can be made out with certainty. The parts missing are fortunately preserved in a smaller specimen of an allied species (Anchisaurus solus) found at the same locality, and these have been used to complete the outline of the restoration. Portions of two other specimens, nearly allied, and from the same horizon, were also available, and furnished some suggestions of value. The restoration as shown on Plate VI. indicates that Anchisaurus colurus was one of the most slender and delicate dinosaurs yet discovered, being only surpassed in this respect by some of the smaller bird-like forms of the Jurassic. The * This Journal, vol. xxxvii, p. 33), April, 1889; vol. xlii, p. 267, September, 1891; and vol. xliii, p. 543, June, 1892, 170 O. 0. Marsh—Restoration of ‘Anchisaurus. position chosen is one that must have been habitually assumed by the animal during life, but the comparatively large fore limbs suggest the possibility of motion on all four feet. The compressed terminal digits of the fore feet, however, must have been covered by very sharp claws, which were used mainly for prehension, and not for locomotion. The small head and bird-like neck are especially noticeable. The ribs of the neck and trunk are very slender. The tail apparently differed from that of any other dinosaur hitherto described, as it was evidently quite slender and flexible. The short neural spines and the diminutive chevrons directed back- ward indicate a tail not compressed, but nearly round, and one usually carried free from the ground. The present restoration will tend to clear up one point long in doubt. The so-called “bird-tracks” of the Connecticut river sandstone have been a fruitful subject of discussion for half a century or more. That some of these were not made by birds has already been clearly demonstrated by finding with then the impressions of fore feet, similar to those made by reptiles. Although no osseous remains were found with them, others have been regarded as footprints of birds, because it was supposed that birds alone could make such series of bipedal, three-toed tracks and leave no impression of a tail. It is now evident, however, that a dinosaurian reptile like Anchisaurus and its near allies must have made footprints very similar to, if not identical with, the “bird tracks” of this horizon. On a firm but moist beach, only. three-toed impressions would have been left by the hind feet, and the tail could have been kept free from the ground. On a soft, muddy shore, the claw of the first digit of the hind foot would have left its mark, and perhaps the tail also would have touched the ground. Such additional impressions the writer has observed in various series of typical “bird tracks” in the Connecticut sandstone, and all of them were probably made by dinosaurian reptiles. No tracks of true birds are known in this horizon. The genus Ammosaurus, represented by remains of larger size from the same strata, was a typical carnivorous dinosaur, and apparently a near ally of Anchisaurus. So far as at present known, the footprints of the two reptiles would be very similar, differ ing mainly in size. The only other reptile known from the Connecticut sand- stone by any part of the skeleton is a large Belodon from a lower horizon. This crocodilian may be called Belodon validus, and will be described by the writer later. New Haven, Conn., Jan. 21, 1893. | AMERICA’ $ VENERABLE AND ONLY WEEKLY poLRCTC FOR NEARLY FIFTY YEARS, ® Littell’s Living Age 18f4 Has stood Peerless in the realm of Perodical Literature. — 7} It selects from the whole field of European Periodical | Literature the best articles by THE ABLEST LIVING WRITERS in every department. Biography, His- tory, Literature, Travels, Science, eos, Criticism, Art, Fiction, and Poetry.* “@Only the best has ever filled its pages; the best thought rendered in the purest English: Nothing poor or unworthy has ever appeared im the columns of THE 4) LIVING AGE.”—The . Presbyterian, Phita- 189: delphia, April 13, 1892. - A WEEKLY MAGAZINE, it gives more than Three and a Quarter Thousand double-column octavo pages of reading matter yearly, form- ing four volumes; presenting a mass of matter Unequalled in Quality and Quantity by any other publication in the country. 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It will be printed.in bold, clear type, on heavy, white, book paper and bound in extra fine cloth, making one large Royal Octavo volume of over 800 pages. — SEND FOR DESCRIPTIVE CIRCULARS. The price given above includes postage on THE LiviING AGE only. The book must be sent at the subscriber's expense. " THE Livinc AGH is published weekly at $8.00 a year, free of postage. TO NEW SUBSCRIBERS FoR THE YEAR 1893 will be sent gratis the two October issues containing a powerful story by Frank Harris, - editor of THE FORTNIGHTLY REVIEW, entitled PROFIT AND Loss. Rates for clubbing THE Livinc AGE with other periodicals will be: sent on application. Sample copies of THE Livine AGE, 15 cents each. Address, LITTELL & CO., Boston. CONTENTS. Arr. X.—Isothermals, Isopiestics and Isometrics relative to Viscosity ; by C. Binus. i bs XI.—* Potential” a Bernoullian Term; by G. F. Becker._ XII.—Datolite from Loughboro, Ontario: by L. V. Prrsson 100 XIII.—New Machine for “Cutting and Grinding thin sections of Rocks and Minerals; by GH Wirtus - 1 XIV.—Stannite and some ‘of the Alteration Products from 7 the Black Hills, 8. D.; by W. P. Heappmn._______._- ae XV.—Oceurrence of Hematite and Martite Iron Ores in — Mexico; by R. T. Hitz; with noteson the associated Igneous Rocks; by W.. Cross, oy. 3S Sa ee XVI.—Cxsium-Lead and Potassium- Lead Halides ; by H. us SW na Soe Ee ea owe ae XVITI.—Ceratops Beds of Converse County, Wyoming ; : by ba: J. Be CHA TORRR Rie Oe ee a 135 XVIII.—Use of Planes and Kite: edges in Pendulums for ie : Gravity Measurements; by T. C. “MENDENHALL..__-_- 144 XIX.—Preliminary note on the colors of cloudy condensa- = | § tion, ‘by C.(Baras (Ul ft “150 ae XX.—Lines of structure in the Winnebago Co. Meteorites = | J and in other Meteorites; by H. A. Newron._---_--.-- 152 esi XXI.—Preliminary Note of a new Meteorite from Japan; | by HAO ASW arp 2 ee oS ee ee AppEnDIx.— X XII_—Restoration of Anchisaurus; by. O.. Cae Mansy: (Wath Plate, V2) os) 3222 oe 5 toe eee 169 — SCIENTIFIC INTELLIGENCE. Chemistry and Physics—Re-conversion of Heat into Chemical ates in the | : production of Gas, NauMANN, 155.--Temperature of Ignition of Hlectrolytie | § Gas, FREYER and V. Meyer: Electromotive Activity of the Ions, NeERNST and PAavul, 156.—Separation of Precipitates at the Surface bounding Electrolytes, — KUMMELL: Chemical Phenomena at low Temperatures, PIcTET, 157.—New Telephotographic lens, T. R. DaLLMEYER: Oxygen for lime light, T. C. Hmp- WORTH, 158.—Interference of Electric Waves: Explanation of Hall’s phenom- enon, HE. LOMMEL: Mercury Voltaic are, H. Avon, 159. if Geology and Natural History—North American Fossil Mammals, 159. —Geology of the Eureka District, A. HaGur, 161.—Geological Survey of Alabama, E. . Smita: Geological Atlas of the United States, Chattanooga sheet, Tennessee: North American Continent during Cambrian Time, C. D. Wacorr: Lafayette Formation, W. J. McGre: Origin and Nature of Soils, N. S. SHALER, 16: Cambrian Fossils of New Brunswick, G. F. Matraew: Experiments in Phys e Geology, KE. REYER: Brief notices of some recently described minerals, 1 ae of Iowa: Astronomical Journal Prizes: Ostwald’s = lassi Exakten Wissenschaften. 168. " ae alae ig | eee i ARCH, 1893. "Established by BENJAMIN SILLIMAN in 1818. THE AMERICAN EDITORS JAMES D. ayp EDWARD S. DANA. Bee ae, ASSOCIATE EDITORS | PROFESSORS JOSIAH P. COOKE, GEORGE L. GOODALE anp JOHN TROWBRIDGE, oF Camsriper. _Prorussors H: A. NEWTON anv A. E. VERRILL, or New Haven, _ Prorussor GEORGE F. BARKER, oF Pat verre THIRD SERIES. VOL. XLV._[WHOLE NUMBER, CXLV.] No. 267.—MAROH, 1893. NEW HAVEN, CONN.: J. D. & E. 8. DANA. . 8.953 TUTTLE, MOREHOUSE & TAYLOR, PRINTERS, 371 STATE STREET. lished monthly. Six dollars per year (postage prepaid). $6.40 to foreign sub- s of countries in the Postal Union. Remittances should be made either by ers, registered letters, or bank checks. 4116 Elm Avenue, oe ‘Philadelphia, Pa, NEW ARRIVALS. OF MINERALS. m Giant Selenites from Utah.—A new lot has been received a foi of wi can be sold as follows: No, 1. 4 feet long, 1 foot in diameter. $50.00. chee No, 2. 2 crystals crossed, 3 feet long, each about 9 inches diameter. $50.00. No. 3. 3 feet long, 1 foot diameter. $40.00. JS eae No. 4. 2 feet 6 inches long, 9 inches diameter. $35.00. No. 5. 18 inches long, 9 inches diameter, double terminations. $25. 00. No. 6. 18 inches long, 6 inches thick. _ S15. 00. All the above are quite well terminated and but very little bruised. All are — quite smooth on several of the faces and several are quite bright. They are undoubtedly the most magnificent specimens ever seen, though for lustre and beauty they will not compare with the brilliant specimens from Sicily. These are certainly unique, especially those which show arragonite, sulphur, ete. _ in their limpid depths. Some have apparently liquid sulphuretted hydrogen en-| _ closed, being extraordinarily fetid. Specimens from Sicily 10e. to $15.00. The ‘sulphurs which I recently brought from Sicily are fhe finest ever seen. The sphenoid and other rare forms are ‘well represented. Specimens at all prices. re For many months past from 500 to 2000 specimens have been unpacked weekly. The stock is now many times the finest in the world. As we received and adver- — tised the Rubellites from California about a year ago, over six months before any other dealer, we have still the largest, finest and cheapest stock. Good specimens showing radiations, some extraordinarily fine, from 5c. upwards. Svabite, Boleite, Hauerite, and hundreds of other new species recently unpacked. 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THE AMERICAN JOURNAL OF SCIENCE [THIRD SERIES.] a ad Art. XXUI—TZhe Diversity of the Glacial Period; by T. C. CHAMBERLIN. In the November number of this Journal, there appeared an article entitled “The Unity of the Glacial Epoch,” by Prof. G. Frederick Wright, that seems to call for a rejoinder, partly to set right the personal views of some whose positions are opposed, and partly to state with a greater approximation to correctness the leading facts bearing on the question and the necessary inferences from them. ‘There are many ques- tions relating to the problem that are legitimate subjects of difference of opinion. Were the article confined to these, it would be foreign to my habit to reply to it. Even as it is, if this were the first or the second or the third discussion by the author that has failed to correctly represent personal views and scientific determinations, I should doubt whether I were justi- fied in writing an article that must necessarily embrace a large controversial factor. The article is not of the nature of a constructive advocacy of the unity of the Glacial epoch, as its title seems to imply, but an attempt at destructive criticism of the evidences ad- vanced in support of the duality or diversity of the Glacial period, and an attack upon the individual positions of some of the advocates of these views. The insufficiency of all argu- ments advanced for duality or diversity, even if demonstrated, would, without positive arguments in proof of unity, only put the question back where it was two decades ago. It would make it simply a matter of doubt, with only conservatism on the side of simplicity. That is an effort of doubtful utility at Am. Jour. Sci.—TsiRpD Serius, Vou. XLV, No. 267.—Marocu, 1892. 172) TZ. C. Chamberlin— Diversity of the Glacial Period. the present time. The advocates of unity should present direct evidences of indivisibility and of the persistence of like conditions throughout the period if they are to merit attention. Destructive arguments have their place in such discussions, but they have an inferior value, unless they are attendants of affirmative arguments. nore Wright's introductory statement of the question seems to me to need radical reconstruction to be even approximately representative of the present attitude of glacialists. If we set aside the views of those who hold glacio-natant theories of the origin of the drift, in whole or in part, there will remain at least four classes of views, with an uiterior fifth class) These may be designated, (1) the primitive views of unity, (2) the later views of unity, (8) the several views of duality, (4) the several views of plurality or diversity, and (5) ulterior syn- thetic views based on exhaustive analysis. 1. Primitive wews of unity.— The old views of unity recognize but a single comparatively short ice invasion (modi- fied by oscillations of the margin), involving but one stage of land elevation followed by one stage of depression, the Cham- plain. Local glaciation was held to be an incident of the retreat, and an elevation was thought to accompany the suc- ceeding Terrace epoch. The stages of elevation and depres- sion were quite generally held to have a genetic relationship to glaciation, but that was not universal, nor is it essential to the classification. It was the view of some that local glacia- tion accompanied the elevation of the Terrace epoch, thus constituting a species of second glaciation, but this is imma- terial so far as the interpretation of the great body of drift in the United States is concerned 2. Later views of unity.—The later views of unity depart somewhat radically from the old ones in postulating a long depression, or series of depressions, in the earlier stages of glaciation (perhaps preceded by a stage of elevation), followed by a prolonged stage or series of stages of elevation followed again by a stage of depression, this last being the Champlain depression in the strict sense of the term. This view differs from the old doctrine of unity in the important and very necessary feature of recognizing at least one early stage of depression, of which several separate episodes of glaciation have already been determined. It also parts company with the old view in entertaining a radically different conception of the extent and complexity of the period and of the import- ance of its constituent episodes. The working methods of those who hold this view are radically different from those of the old school, as well as their habits of interpretation, in that they are analytical and discriminative in respect to structural, T. C. Chamberlin—Diversity of the Glacial Period. 178 genetic and historical factors. In these respects, this view does not very essentially differ from the following views. It only diverges from them in recognizing the whole complex series of glacial movements as connected and bound together across the episodes of retreat and advance by conditions that are to be interpreted as signifying continuity rather than dis- continuity. 3. Duality.—The several views of duality differ in detail, but they agree in recognizing one, and only one, epoch of deglaciation of such nature and importance as to justify a division of the period into epochs by means of it. Each of the two epochs is held to have been marked by episodes of ice advance and retreat and other changes, .but these are thought to be subordinate to a bipartite division. The separation of the epochs of lake-tormation in the Great Basin region by an interval of aridity, the separation of the epochs of glaciation of the interior by an interval of extensive and high-gradient erosion and weathering, and the intervention of a temperate fauna and flora between glaciated deposits in Europe, are typical illustrations of the class of data to which these views appeal. It is not essential to prove or to hold that the ice completely left the continent, any more than it is necessary to prove or to hold that the sea retreated from the land between the recognized epochs of the Niagara period. The question is not a question of two glacial periods but of two glacial epochs, as these terms have come to be commonly used in America and England. This does not make the distinction merely a choice of terms. It is a distinction of ideas, and of not unim- portant ideas. The dualist holds that he has grounds for an important subdivision of glacial history comparable in signifi- cance to that which divides the periods preceding. There is, it is true, an element of judgment here, as in all similar cases, but back of that there is an essential distinctness of ideas. 4. Plurality or diversity.—Some of the most experienced glacialists of Europe and of this country who have held to the last class of views, have come to feel their inadequacy in the interpretation of the vast growing mass of evidence, and have enlarged their views in the direction of still greater diversity. ‘These have come either to recognize three or more glacial epochs, or to feel that the diversity is so great as to make a simple bi-partite division unsatisfactory. One of the latest and most notable expressions of this class of views is to be found in a recent paper by Dr. James Geikie, ‘“‘ On the Glacial Succession in Europe” (Trans. Roy. Soc. Edinburgh, May 16th, 1892) in which five glacial epochs are recognized, and a map of the distribution of the ice in the second and fourth of these epochs is given. 174 7. C. Chamberlin—Diversity of the Glacial Period. 1. Doubtless nearly or quite all the older students of drift, of the glacial school, once entertained views that should be placed under the first class. Such views linger with some whose later attention has been turned in other directions chiefly, and with some whose studies have been confined to areas presenting only one time-phase of the drift conspicu- ously, and some hold these views for reasons less felicitously explained. I should class Professor Wright’s views in the primitive group. He is doubtless in advance of many phases of the older views and his papers show some progress, but he has failed to definitely recognize and accept two stages of depression separated by an important stage of elevation. This is best illustrated by his position respecting the formations of the Delaware region, which will be noted further on. His impression of the extent and complexity of the ice age is of the earlier rather than of the later order. He does indeed use terms that by themselves would signify great extension and complexity, but he employs arguments and interpretations which show that they carry a significance very different from that which is given them by those who take the newer and enlarged views of unity. or instance, he objects to the reference of the erosion of the lower gorge of the Allegheny and Upper Ohio Rivers to an interglacial epoch on the ground of the length of time required by the erosion, and speaks of such views as “meking unnecessary demands on the forces of nature.” (Man and the Glacial Epoch, p. 218.) His deserip- tions of the Ice age in his two books and elsewhere seem to me to convey an archaic and bedwarfed impression both of the extent and complexity of the period. I cannot, therefore, think that his views of the glacial period have any such exten- sion as would entitle them to be classified under the newer views of unity. The most serious phase of the matter is that neither analytical methods nor their results seem to find even an approximately accurate reading, much less exposition and discussion, at his hands. 2. The later views of unity seem to have few, if any, declared advoeates, due, doubtless, to the fact that as soon as a glacialist comes to realize the nature of the phenomena invol- ved to an extent sufficient to cause him to dismiss the primary views, he quickly passes on into the third or fourth class, or else takes an attitude of conservatism and reserve, and awaits further evidence before engaging in a definite advocacy. These views are, however, entitled to a distinct place and to full recognition, because they not only represent the attitude, whether transient or otherwise, of a considerable body of gla- cial students, but they are still kept among the working hy- potheses of many who employ the method of multiple working T. C. Chamberlin— Diversity of the Glacial Period. 175 hypotheses. That method requires that all hypotheses not absolutely excluded by evidence should be retained in the working group. If any doctrine that can properly be desig- nated a doctrine of unity shall ultimately prevail, it will be one that will be developed along the lines of effort which characterize this class and distinguish it from the first class. So far as the attitude of those who entertain this class of views concerns analytical methods of working, it stands, so far as it is typical, in sharp antagonisin to that of the advocates of the first class, because the ultimate establishment of their views depends upon the clear discrimination of the glacial deposits that were formed in the apparent intervals appealed to by the advocates of the third and fourth classes and upon the demonstration that such episodes of glaciation occupied these intervals. This involves not only the clear discrimina- tion of the intervals but the determination of the special deposits that bridge them. This demands the utmost re- sources and highest refinements of analytical and disecrimi- native methods. Success will not lie in ignoring or belittling the extension of glacial time or the greatness of the inter- vals now discovered; but, if attained at all, it will be through ability to fill in the gaps with undiscovered deposits and to bridge over the unquestionable changes of surface attitude with gradational stages and concurrent glaciation, and to demonstrate that the variations in the character of glacial action took place by such gradual steps as to bind the whole into inseparable unity. This requires an attitude toward discrimi- native work precisely opposite that assumed in Professor Wright’s discussion of the subject. 3. It is difficult to name, and moreover unprofitable to attempt to name, the glacialists who at the present hour advo- cate the doctrine of duality as distinguished from plurality or diversity, since so many of those who some time ago felt com- pelled by evidence to believe in at least one interglacial epoch, but who were not convinced that it was necessary to recognize more than one of the major type, have in recent years passed on to, or at least toward, the recognition of two or more such intervals under the impress of the accumulation of evidence. No one can have followed conscientiously the onward move- ment of opinion during the last few years and have failed to note the strong drift from simple duality toward either a strongly diversitied duality or toward plurality. In the midst of this movement, it is idle, as well as harmful, to attempt to define the positions of individual glacialists in so far as they have not recently defined them for themselves. 4, What has just been said applies to the lower limit of the fourth class, but there are some whose declared opinions make 176-7. OC. Chamberlin—Diversity of the Glacial Period. this a distinct and important group. The very able paper by Dr. James Geikie, already referred to, is a notable expression of advanced opinion of this kind. Incidentally it indicates a similar attitude on the part of some other European glacialists of large and varied experience and of unquestioned ability, and some American glacialists have indicated at least a hospit- able attitude to similar views. A comparison of the actual position of Dr. Geikie with that assigned him by Professor Wright, and a comparison of the array of evidence which Dr. Geikie advances with the treatment it received in the article in the November number of this Journal is one of several illustrations of the ground of my protest. 5. There is an ulterior synthetic view to be based on a previous exhaustive analysis to which every cautious. student of the subject looks forward as the ultimate interpretation. This is an ulterior view because it is impossible to take such a view at the present time, except in a crude prophetic sense- The method may now be clearly seen but the data for its realization are not at hand. The first step toward it is a thoroughgoing analysis of the glacial complex into its con- stituent deposits and the definite delineation of these both in plot and in section involving the tracing out of the connections and the correlations of the constituent sheets, the determina- tion of the intervals that occur at different horizons and in different sections of the country (for they are not the same everywhere), and the evaluation of the nature and length of the intervals and their climatic, orographic and other character- istics. Then will come the final test of the unity views, in the demonstration, or the failure to demonstrate, that episodes of glaciation fillin the intervals and bind the whole into indi- visible unity. Then will come, also, the final test of the doctrines of duality or diversity in the establishment, or non- establishment, of intervals which prolonged research has failed to bridge, and which temperate faunas and floras show to be necessarily interglacial intervals, unless there be brought into the series the distant polar connections which are presumed to exist in any case. It isin the interest of each of the classes, unless it be the archaic one, to press on analytical and discrimi- native studies and to give to them and to their results full recognition. Immediately following his general statement of the question, Professor Wright remarks, ‘‘ In approaching the subject, it is important to notice the fact that Professor Chamberlin inaugu- rated his induction as director of the glacial division of the United States Survey by publishing a monograph of “The Terminal Moraine of the Second Glacial Epoch” [correct title ‘Preliminary Paper on the Terminal Moraine of the Second T. CU. Chamberlin— Diversity of the Glacial Period. 177 Glacial Epoch], thus assuming the truth of his theory in the title.’ Iam puzzled to see how the title “ The Terminal Mo- raine of the Second Glacial Epoch” any more assumes the truth of a theory than the title “The Unity of the Glacial Epoch.” If the purpose of the sentence was to convey the impression that I commenced my consideration of the subject by assum- ing the truth of the duality theory, it is precisely antipodal to the fact. This paper was my seventh discussion of the moraine or some part or phase of it. The first of these was prepared while I entertained primitive and inherited views closely similar to those which Professor Wright now advocates. These views I gradually abandoned as my information increased and my series of papers show a progressive change of opinion. It was only at the close of my official work on the Wisconsin Survey, when called upon to sum up and interpret finally the results reached, that I definitely announced an abandonment of the old view and an acceptance of the dual view, assigning reasons therefor.* If anything relative to the history of my personal views is of any importance in the matter (which is not my assumption), it is this statement of change of view at the close of several years ot consecutive study, a statement which had more of a final than of an inaugural character. The effort of Professor Wright to lay the groundwork of presumption that my whole interpretation of the facts bearing on the duality of the epoch is possibly a mistake by reason of a change in my mapping in Illinois would have been without force had he made a fair statement of the case. He states, “in this preliminary monograph (see pp. 322-326) the moraine is made to correspond with the kettle moraine of Wisconsin, and to hug the southern shore of Lake Michigan, but in the Seventh Annual Report of the U. S. G. Survey the later glacial drift is carried down to Bloomington more than one hundred miles farther south, while at the latest date Mr. Leverett (Am. Geol., July, 1892, p. 23) specially deputed by Professor Chamberlin to look ater the moraines, draws his later moraine line one hundred miles still farther south, through Litchfield, Hillsboro,” ete. (p. 353.) There is here a complete omission of all reference to the provisional lines which were marked with dots on the map in my earlier paper, and concern- ing which the following was said in the text :+ “There may be no more fitting place to make a qualifying remark in regard to the whole region between the moraine above traced and that adjacent to Lake Michigan. The drift of this area bears undoubted evidence of being recent, and, though this is in considerable part due, superficially, to aqueous * Wis. Geol. Sur., vol. i, pp. 271, 272. + Third Ann. Rep. U.S. Geol. Sur., 1883, p. 331. 178) 7. C. Chamberlin— Diversity of the Glacial Period. agencies, it seems to me probable that the region will prove to have been largely, possibly completely, covered by ice in the earliest stage of the second glacial epoch. It is not, however, traversed by conspicuous moraines, at least not by any as well developed as those above outlined. Low ridged belts of sub- dued morainic aspect have been observed at numerous points, but their relations have not yet been traced out. “A similar qualifying remark may be here made concern- ing a considerable area in Northern Illinois, outside the mo- raine described in this paper. The freshness of its drift, and the unsculptured contour of its surface, bear evidence of recent origin. Some portions of this area seem clearly to be of lacustrine and fluviatile origin, at least superficially, and IL have at times supposed that all might be due to waters mar- ginal to the adjacent glacier, since there is no conspicuous bordering morainic ridge; but the tendency of recent evi- dence, gathered in a-special study of this class of deposits, seems to favor the hypothesis of more extensive glacial occu- paney, even where the evidence of it in obvious moraines is feeble or wanting. This questionable region is now under investigation. ‘The dotted lines on the map indicate some of my working hypotheses.” Prof. Wright neglects to say that my later mapping relates to this area, thus announced to be under investigation, and that its morainic lines were such as the preliminary map had foreshadowed. He further failed to say that this later map was one constructed merely to exhibit the location and direc- tion of striz in connection with my paper on ‘‘ Rock Scorings of the Great Ice Invasions.”* I have not yet re-discussed the region nor the moraines in question. The more recent investi- gations bring out into clearer definition and justification the ground of doubt which lay in my mind at the time of the first mapping, for they show that there are two groups of moraines representing two important episodes of glacial his- tory, and that both mappings will be retained, when corrected and perfected, as factors in an ultimate differential map of the drift of the region. To demonstrate their exact correlations east and west still remains ditticult, because the later lines override the earlier at large angles and conceal their connec- tions, and because the moraines of both epochs bunch them- selves in the reéntrant angles between the ice lobes in such a way as to make their demonstrative disentanglement a work of extreme difficulty. On this account I have left the pro- visional correlations set forth in the earlier paper standing without re-discussion, that the work of later correlation might be the freer. * th Ann. Rep. U.S. Geological Survey, pp. 147-248. T. C. Chamberlin—Diversity of the Glacial Period. 179 Having made it appear by such omissions that I had changed my mapping to the amount of a hundred miles, Professor Wright states that Mr. Leverett draws “his later moraine line” one hundred miles still farther south. If by this ex- pression it is meant that Mr. Leverett referred this moraine line to my second glacial epoch, I think a reading of Mr. Leverett’s language will fail to show warrant for it. Mr. Leverett distinctly recognized two groups of moraines coinci- dent with two orographic attitudes. He did not discuss the relations of either of them to my correlations. If it is meant simply that this moraine was announced “later” than the others, it has no pertinence, unless it is assumed that any moraine of any sort is to be referred to my later epoch, which is not Mr. Leverett’s view nor mine. As to still more south- erly moraines, Mr. Leverett and myself are quite aware of the hilly belt at Greenville (whose course it may be remarked in passing makes a high angle with the drift border) and also of other more or less definable but obscure tracts of thickened drift of a terminal or quasi-terminal kind. It is a part of our hope and expectation to be able at length to trace out obscure sub-marginal thickenings of the drift sheets, and other quasi- marginal markings of one kind or another, over the whole drift field, old as well as new, where the more pronounced ter- minal moraines are absent. This has formed a feature of my plans for many years and considerable preliminary data have been gathered and some detailed tracing has been done in pur- suit of it, in connection with work on the more important and significant moraines which mark advances of the ice and define glacial episodes if not epochs. Some of these moraines of minor significance have been mapped, and others are yet to be added. Some of them will lie not far from the border of the drift at some points, and it is to be hoped that the more ob- secure older drift will yield marginal indices in all districts sufficient to show its history with approximate accuracy. With this in view, I have developed new criteria of discrimination and have proposed additional distinctions between marginal moraines and have sought other marginal and submarginal markings suited to the requirements of this more critical work. Of course a map showing all these moraines and marginal lines without indicating their differences, gives a more or less anti-divisional impression, much as does the diagrammati¢e geor logical column of the text-books and dictionaries, and of course it is possible to lump these all together as “ moraines of recession,” or ‘“ receding moraines,’ just as all the sedimentary strata south of the Archean terrane may be disposed of as deposits of sea-recession. These moraines are moraines of ice- retreat in much the same sense as the Paleozoic sediments are 180) 7. OC. Chamberlin—Diversity of the Glacial Period. beds of sea-retreat. There was a general retreat in both cases, but there were advances in both cases, and the recognition of these constitutes the essence of the science in both eases. Besides the implications involved in the attempt to make the older moraines—even undiscovered ones—do duty as cor- relatives of what others regard as obviously much younger ones of different character, there is a specific erroneous im- pression conveyed by the statement that closer observation is not unlikely to carry the exterior moraine farther south still which would be “‘all that is necessary to make the extreme boundary stand related to the moraine there as it does through- out the eastern part of the Mississippi Valley.” This carries the implication that there is a constant relation between the extreme boundary and the outer terminal moraine in the eastern part of the Mississippi Valley. This is not the case. The fresh stout moraine that lies near the border in the upper Ohio region departs from it In going westward and disposes itself in a strongly looped fashion that is not coincident with that of the border. It is precisely because of this lack of coincidence and because of the marked differences in the char- acter of the drifts that a distinction between them is urged. In Illinois there is nothing within a hundred miles of the border that presents any rational grounds for correlation with the outer terminal moraine in Western Pennsylvania. Professor Wright claims to have spent five seasons on the border between Penn- sylvania and the Mississippi River,* and yet he has not found in Western Ohio, Indiana and Illinois any such moraine-and- “fringe” in any such relationship as he has so often described in Western Pennsylvania. One would think that five seasons, work would give a better suggestion of what is likely to be found true respecting a moraine-and-“ fringe” border, than the one offered to the effect that Mr. Leverett or some one else is not unlikely yet to find a moraine of some sort somewhere near the border. In Bulletin 58 U. 8. Geol. Survey (p. 75) Professor Wright says, “In Illinois nothing like a moraine was encountered in any portion of the State which I traversed, which ineluded Randolph, Perry, Franklin, Jackson, William- son, Saline, Gallatin and White counties ” Mr. Leverett recognizes the following stages applicable to the region between its limit of drift in southern Illinois and the the head of Lake Michigan. Ist stage. Sheet of drift averaging perhaps 20 feet in thick- ness. Intervals of slight or partial deglaciation shown by oceasional presence of soil between sheets of till. 2nd stage. Interval of deglaciation of great length. Sur- face of old drift sheet deeply oxidized, leached and much eroded. Thick and widespread soil. * The Dial, Dec. 16, 1892, p. 380; Jan. 1, 1893, p. 7. T. C. Chamberlin— Diversity of the Glacial Period. 181 3d stage. Deposition of main body of lcess and associated silts. Apparently very low altitude and slack drainage. 4th stage. Long interval of deglaciation. Large valieys cut in loess. 5th stage. Formation of thick drift sheet with morainic bor- der 75 to 100 feet deep. Ice reached Shelbyville (not Litch- field) at maximum advance. Later sub-stages of glaciation marked by moraines or thickenings of drift at the margin of the sheets (40 to 50 feet). Intervals between successive moraines probably short since evidences of oxidization, leaching, erosion and soil accumulations are scant. Elevation about as at present when Shelbyville moraine was formed. Drainage less vigor- ous when later moraines of this stage were formed. 6th stage. Interval during which ice lobes and ice currents were shifted. Length probably considerable, though decisive evidence is wanting. 7th stage. Latest series of ice lobes south of Lake Michigan formed. Elevations greater. drainage freer. Minor moraines marking later sub-stages. Followed by the lake deposits of the region. Mr. Leverett is inclined to correlate the outer moraine in Eastern Ohio and Northwestern Pennsylvania (there called the terminal moraine in a double sense by some-writers), with the outer member of this last group, which is about 240 miles from the extreme limit of drift in Illinois, but owing to the fact that the moraines in the intervening region became bunched together in the angles between the ice lobes, an entirely demonstrative correlation by tracing is difficult, and he withholds a final judgment. But leaving the doubt as wide open as the phenomena will admit, he regards a correlation of the outer moraine of Western Pennsylvania with anything within 120 miles of the southern limit in Illinois as opposed to all evidence. In his elaborate monograph on “ The Pleistocene History of of Northeastern Jowa,”* Mr. McGee defines and illustrates, with great fullness, the following series: 1. A lower till ranging in thickness from a mere veneering to 200 feet, averaging perhaps 50 feet, characterized by green- stone erratics (in contrast with the granitic erratics which characterize the upper till); nowhere displaying a moraine- like peripheral thickening, but everywhere attenuated toward its margin. General facies ancient, ferrugination and oxida- tion greater than that of upper till. 2. A forest bed found in 40 per ceut of the well-sections, 20 to 25 per cent of them showing a definite bed. Old soil * 11th Annual Report U. S. Geological Survey. 182. 7. OC. Chamberlin—Diversity of the Glacial Period. thicker than that of to-day. Pine, oak, elm, sumac, walnut, willow, ash, hickory, and tamarac recognized. 3. An upper till, ranging in thickness from a veneering to probably 100 feet, averaging perhaps 20 feet. Erratics gener- ally granitic. Grades horizontally at the south into loam, and vertically either grades upward into loess, or is overlain with a certain unconformity by loess. Only rarely and locally do terminal moraines mark the margin. 4. A loess mantle, which in part grades into the upper till, and in part overlies it with a definite dividing plane between. Regarded as a deposit contemporaneous and continuous with the upper till. These formations are older than the moraine-bordered tongue of till which occupies the north central part of the State and they pass under it. They are separated from it by great general erosion, oxidation, leaching, ete. Back of this le the complicated moraine-bordered deposits of Minnesota. We have here, therefore, a series comparable to that on the east side of the Mississippi. The upper till of Mr. McGee was deposited at a time of slack drainage. The moraine-bordered tongue of Central Iowa was deposited at a higher gradient, as shown by the freer drainage from its edge. It thus appears that the latest studies of these two experi- enced investigators, the fullness and detail of whose work in this region is unsurpassed, bring into clearer and sharper defi- nition than ever before, the distinction between these drift sheets, and magnify the importance of the intervals. While the question of one or more epochs is not necessarily dependent upon that of the origin of glaciation, there is so intimate a connection between them, that whatever bears upon the one, is not without application to the other. If the great intervals of deglaciation and the great advances of the ice were due to astronomical causes of the type advocated by Croll, every great change, being due to a reversal of the action of the controlling agency, is entitled to distinct recognition. If the chief cause of glaciation is northern elevation, any evi- dence which shows a depression far to the northward carries with it as a logical conclusion the assumption of general deglaci- ation. Prolonged glacial action at low altitudes puts the theory to a severe strain. Halts and advances at low altitudes impose still greater difficulties, the more severe the greater the interval. Even if it is granted that just after the ice reached its max- ‘imum extension, a depression took place because of the load- ing of the ice and that low gradient deposits attended the retreat of the ice, it is evident that there could be no consider- able readvance without a restoration of high altitude. For instance, the ice could not rationally be presumed to retreat to T. C. Chamberlin—Diversity of the Glacial Period. 1838 the northward and remain long enough to permit the accumu- lation of a soil equal to that of the present and then advance again while the country still lay at a low altitude. It certainly could not be supposed that the ice would retreat so that low- eradient deposits should take place six or seven degrees of latitude back from the edge of the ice without general degla- ciation also taking place. Now, in the Mississippi Valley we have silt deposits spreading over many thousands of square miles and connecting themselves with the second main drift sheet of the series given above. They overlie the oldest drift throughout large areas but are separated from it by a soil hori- zon. (The older drift seems to have its own silt-appendices in some regions also.) These silts occur on the highlands ad- joining the main rivers throughout the older glaciated regions from Ohio to Nebraska, and they reach northward to the west- ern part of Wisconsin, the southeastern part of Minnesota, the southwestern part of Minnesota, the southeastern part of Dakota and the northern part of Nebraska, and from these tracts they extend without detectable interruption to the gulf region. In other words, they reach seven degrees north of the extreme drift limit in the Mississippi region and six de- grees in the Missouri region. T'o account for the phenomena in harmony with the hypothesis of glaciation by elevation, it appears to be necessary to suppose that the northern region was elevated to a height sufficient to cause an ice sheet to creep down to a point south of the latitude of 58 degrees on a plain of great extent; that this was followed by a depression sufticient to cause the withdrawal of the ice for an unknown distance and to remain withdrawn long enough for a soil and for peat and forest beds to accumulate to thicknesses fully comparable to those of the present; that there was then an advance sufficient to form the second till which overlies this forest bed, followed by a retreat under such conditions as to permit silts to gather over the wide areas indicated for six or seven degrees northward and at considerable heights above the present streams, spreading well back on the uplands. Nowa depression that would permit a deposit of these silts through- out this great extent and at these heights, carries with it the presumption of the removal of the ice from the whole north- ern region, because the depression is assumed by the hypothesis to have been caused by the ice itself, and to have been pro- gressively greater to the north, and so, unless an entirely in- consistent supposition be interpolated, the northern region must be presumed to have been lower than it is to-day. The great extent of silts, therefore, in the Mississippi region car- ries with it the presumption of complete deglaciation of the northern region, if elevation be assumed to be the chief cause 184 7. ©. Chamberlin—Diversity of the Glacial Period. of the Ice age. This, it seems to me, holds good under any form of the aqueous hypothesis of these silt formations that is consistent with the phenomena. If they are attributed to wind action, the aridity and the combination of conditions necessary for the accumulation of the silts make the presump- tion of disappearance of the ice equally great. Subsequent to this period, on the theory of elevation, there must have been another uplift at the north sufficient to cause the ice to readvance to points as far south as the first advance in certain regions, and within 300 to 500 miles of the first advance in others. Now an elevation sufficient to produce glaciation as far south as 38°, followed by a depression sufficient to permit silts to accumulate 7° north of this, followed by another elevation sufficiently great to cause ice to advance to like degrees of latitude, in the main, seems to me a sufficient change in the great agency of the time and a sufficient orographic movement to justify the distinction of separate epochs. So far as I can see, nothing less than these extraordinary oscillations are sufli- cient to explain the phenomena, and to these must be added minor oscillations of very considerable moment. For myself the phenomena of low altitude deposition seem so great and so completely demonstrable as to be fatal to the hypothesis. But if not, the very multiplication of overlapping sheets and marginal moraines signifying halts-and advances, that is appealed to in the endeavor to weaken the evidence of two or more epochs. bears in precisely the opposite direction when the demonstrable conditions of such halts and advances are duly taken into consideration. In the matter of the “ fringe,” Professor Wright’s statement, “The fact that the oldest part of the glaciated region ‘is not bordered by a definite terminal moraine, but ends in an attenuated border’ is only another way of stating the fact which Lewis and I began to urge upon the attention of the public ten years ago during the early part of our investiga- tions,” is unwarranted and tends to confusion historically and scientifically. The chief questions regarding these phenomena were squarely and broadly before scientific readers before Professors Lewis and Wright urged their single view of one variety of the phenomena. But that is a trivial matter. On the contrary, the confounding of the phenomena designated and interpreted as a “fringe” with the phenomena of the attenuated border is a serious source of error. The phenom- ena are not only not equivalents, but they stand in some measure as antitheses. There are four classes of facts to be distinguished. T. C. Chamberlin— Diversity of the Glacial Period. 185 1. A drift sheet bordered by a terminal moraine attended by seattered drift on its outside formed at the same time as the moraine by minor incidental action. This scattered drift may not inaptly be called a “fringe.” It is a trivial phenomenon, a mere incident of the main action. 2. A drift sheet that, in contrast with the above, thins out gradually to an attenuated edge. A specific example of this, described in detail, may be found in the Sixth Annual Rep. U. S. Geol. Surv., p. 265. There may be scattered incidental drift on the border of this as well as of the moraine. 3. A bordering tract of scattered bowlders, sometimes reach- ing out many miles beyond any continuous drift. The origin of this is not certainly known, but it is probably due to tem- porary bordering lakes or glacial floods. It is well developed at some points in Dakota and Montana. 4. A bordering tract of scattered pebbles attended by silt. This is probably due to glacial waters acting at low gradients in conjunction with detached ice, perhaps local, perhaps glacier derived. An example of this is described in detail and dis- cussed in the paper above cited (p. 271.) To confound all these and to merge them under a single term is to push science backward. It is especially unfortunate to create confusion respecting the vital distinction between a moraine-bordered sheet with incidental drift scattered outside, and a thin-edged sheet that may be attended by similar scattered drift. The scattered bordering drift is trivial in significance in either case. This is especially so when the terminal action is strong and vigorous, expressing itself in a definite moraine and when the outer drainage is free. The attenuated edge, as distinguished from the moraine-thickened edge, has a radi- eal significance, because it expresses a vital distinction in mode of action. If the term “fringe” had been confined to the first class of phenomena, and “the phenomena discriminated with reasonable accuracy, its introduction might prove a con- venience. But the attempt to make it asynonym with the “attenuated border” which happens to be the form the old drift sheets assume, and the failure to distinguish the two phenomena has made its introduction most unfortunate and renders the propriety of its further use very questionable. The more important phenomena outside the Pennsylvania terminal moraine to which the term “ fringe” has been applied I think has been demonstrated to be the border of an older drift sheet, and not at all a “fringe” of the terminal moraine with which it has no genetic connection. Turning to the phenomena of the Delaware Valley, it will assist to a clear understanding of the question if it be recalled that in the original mapping of the drift of the region by the 186 7. & Chamberlin— Diversity of the Glacial Period. geologists of New Jersey and Pennsylvania, the terminal mo- raine which crosses the river at Belvidere, and which may be spoken of conveniently as the Belvidere moraine, was repre- sented+as the boundary of the glacial drift. This was not rigidly affirmed by the geologists of New Jersey, and from per- sonal statements made to me by Professor Cook at the Paris International Geological Congress in 1878, soon after the appearance of his report on that region, and from recent state- ments of Professor Smock, it appears that a knowledge of some drift outside of the Belvidere moraine was possessed by them, and that the moraine was regarded as representing only the approximate border. Professors Lewis and Wright insisted much more rigidly upon the limital character of the moraine ;* and Professor Lewis published a paper subsequent to his final report on the terminal moraine, in which he attempted to show that all the supposed drift outside of the moraine in Pennsyl- vania except obvious valley wash was illusive.t In recent years several geologists, notably Professor Salisbury, have observed drift on the uplands, extending to a distance of at least 25 miles south of the moraine. are occurrences of gla- ciated bowlders have been found fully 60 miles south of the moraine. Professor Salisbury refers a portion of this extra- morainic drift extending in places at least 12 miles beyond the moraine, to direct glacial action at a time much antecedent to the formation of the Belvidere moraine. Respecting other and generally more distant deposits he has reserved opinion. It is fair to those geologists who in an early day overlooked this outer drift, or failed to see its full meaning, to note that in its character and expression it is markedly different from the drift of the moraine and from that within it, and that this is ample excuse for the oversight at that stage of work. But even then it did not escape Professor Smock, although we are not aware that he has anywhere published statements concern- ing it. The oversight is less pardonable if the truth be, as insisted by Professor Wright, that this outer drift is of the same age and kind as that of the terminal moraine. Notwithstanding his own oversight, Professor Wright insists that those who saw at once the essential facts upon their first visits failed to see what ordinary competency required. In particular, he asserts that Professor Salisbury is in error in referring to a glacial origin the deposits at High Bridge and Pattenburg, which le about 12 miles distant from the nearest point of the moraine. He claims to be able to demonstrate this. One essential part of his demonstration is the assertion * Second Geol. Sur. Penn., Rep. Z, p. 45. + On supposed Glaciation in Pennsylvania South of the Terminal Moraine. This Journal, Oct. 1884, pp. 276-285. T. C. Chamberlin— Diversity of the Glacial Period. 187 that “There is no foreign material in the cuts, at least, Professor A. A. Wright and I could not find any”; (p. 307) and a second is that drift from the Medina sandstone is absent from these localities, and that its absence is decisive. 1. The absence of any single lithological element is not demonstrative of the absence of drift of glacial origin. Only a short distance to the north, the whole group of crystalline erratics is reported by Professor White to be absent from a large part of Susquehanna and Wayne counties.* No one questions the glaciation of that region because of their ab- sence. Most experienced glacialists I think must have en- countered similar instances of the local absence of a particular rock constituent. Such apparent absences over considerable areas have been encountered by Mr. Buell in a specially care- ful tracing of bowlder trains from the isolated crystalline knobs of Wisconsin, and for a time such absence seemed to indicate a limitation of that particular kind of drift; but further search has shown that beyond this barren area the par- ticular erratics reappear and extend onward for considerable distances. 2. It so happens that Mr. Kummel of the New Jersey geological survey, without a knowledge that the localities were the subjects, or were likely to be the subjects of special ques- tion, made collections of. rock specimens at both High Bridge and Pattenburg, simply with a view to rendering them as com- plete and representative as possible. Upon request, these col- lections have been sent to Chicago and examined, and Professor Smock has also kindly given his opinion of them. Referring to a group of specimens belonging to the collection, Professor Smock expresses the opinion that ‘they belong to or have come from the ledges of Cambrian, Green Pond Mountain and Potsdam, in New Jersey and New York. Of course it would be possible to duplicate the lot in the Green Pond Mountain range in the Kittatinny Mountain series, and in the Potsdam.” These all lie at distant points. Among the speci- mens are pebbles of sandstone so closely resembling the Medina sandstone that only an expert familiar with the special character of the formation in New Jersey could give an opinion of any value at all. Professor Smock, after a careful examination, does not feel justified in giving a positive opinion. In the presence of these specimens, the alleged absence stands upon a very slender basis. The collections contain specimens of gneiss, sandstone of at least two distinct types, quartzite, shale of two kinds, and chert. These appear to represent certainly five different * Sec. Geol. Sur. Penn., G 5, 1880, p. 26. Am. Jour. Sci.—TuirpD Spries, Vou. XLV, No. 267.—Marcn, 1893. 14 188 2. C. Chamberlin— Diversity of the Glacial Period. formations. This petrographic variety, taken in connection with Prof. Smock’s opinion, seems to be a sufficient answer to the claim that there is no foreign material in the euts. As a collateral point, Professor Wright asserts that ‘“* South of Musconetcong Mountain stretch the Triassic red shales which cover so much of the central part of New Jersey. But in this portion of the State, there has been absolutely no trans- portation of northern material out upon the Triassic shales, showing that no movement here ever passed the Musconetcong Mountain” (pp. 365-6). Drift lymg upon the Triassic shales is reported to occur at the following points by the following observers : 1. West and N.W. of Pittstown. | A. R. Whitson. 2. Hensfoot. H. B. Kummel. 3. Pattenbure. R. D. Salisbury, C. E. Peet and H. B. Kummel. 4, South of White House Station. A. R. Whitson. 5. North (13 or 2 miles) of Somerville. F. C. Schrader and R. D. Salisbury. 6. New Brunswick. C. E. Peet, R. D. Salisbury. 7. Liberty Corners. F. C. Schrader, R. D. Salisbury. 8. Berkley Heights. A. R. Whitson, R. D. Salisbury. 9. New Vernon. R. D. Salisbury. 10. Bernardsville. F. C. Schrader, R. D. Salisbury. 11. Basking Ridge. R. D. Salisbury, F. C. Schrader. Tt is not affirmed that all these are direct glacier deposits, but they are identified as drift and other than obvious valley drift. Of these, the Pattenburg and Hensfoot deposits and the area near Pittstown lie south of Musconetcong Mountain and fall directly within the territory alleged to be barren. The remaining localities lie to the east of this, and while they do not come within the strict limits of Professor Wright’s statement they bear on the general question involved. Of these localities, all, or nearly ail, lie in such topographical situations as to absolutely exclude the interpretation placed upon the High Bridge and Pattenburg deposits by Professor Wright. It appears, therefore, that he has based his assumed demon- stration, first, upon a general proposition that experience has shown to be entirely inadmissible; secondly, upon the absence of foreign material at High Bridge and Pattenburg when the specimens gathered by a young geologist sent there merely to make a representative collection embrace a large variety of rock specimens unrepresented by formations in the vicinity and referred by Professor Smock to distant terranes; and thirdly, upon an assertion, in the most positive terms, of the absence of drift on the Triassic areas south of Musconetcong Mountain, when such drift is found there by other observers. _—~ T. C. Chamberlin— Diversity of the Glacial Period. 189 Turning now to the interpretation which Professor Wright puts npon the High Bridge and Pattenburg deposits, it is to be noted first, that the one occurs upon a spur as shown by the New Jersey topographical maps and that to reach higher ground a line running along the back of the spur must be fol- lowed, rather than one down the maximum slope in the most natural line of slide and creep. No height exceeding 460 feet above the deposit in question occurs in the neighborhood, except such as are separated from it by depression ; and to reach even this moderate height, it is necessary to go one mile back from the locality. In the other case, heights 500 feet above the area in question occur within two miles to the north, but they are separated by gentle slopes and a shallow valley. The slope on which the deposit lies is composed of ‘Triassic rock. These facts bear upon the suggestion of Professor Wright that these deposits are due to degradation, slide and creep. Bearing more specifically upon that interpretation is the fact that in these deposits there are bowlders and pebbles of rock not now in the adjacent ridges, and these are polished and scratched in a manner precisely similar in every respect to the well-known polishings and scratchings of glaciated pebbles. One or two in the collection of Mr. Kummel take rank among the best examples of typical glaciation; and if they were passed through the hands of a hundred glacialists of the greatest experience, not one could be expected to hesitate for a moment to refer them to glacial action. Nothing at all closely simulating them has ever been reported as the demon- strable work of either land slide or creep. Furthermore, the deposits in question are in part distinctly stratified, a feature foreign to the products of landslide and creep. The deposit at High Bridge is about 30 feet in maximum thickness, and that at Pattenburg scarcely less. To refer to creep or landslide deposits having these con- siderable thicknesses, containing derivatives from five forma- tions, embracing nine recognizably different varieties of rock, a part of the deposits being stratified, and containing in both localities scratched stones, the glacial origin of which no gla- cialist would ever independently question, is most extraordi- nary in what claims to be a demonstration of an illusion on the part of one of our best trained and most critical observers. As another proof of alleged error on the part of Professor Salisbury, Professor Wright says, p. 864: ‘The extensive oxidation spoken of by Professor Salisbury in the quotation made from his recent reports on the glacial deposits of New Jersey is clearly of preglacial origin.” That extensive oxida- tion affected the old surface material that became a part of the old drift, here as elsewhere, goes without saying. In a profes- 190 27. C. Chamberlin—Dwversity of the Glacial Period. sional discussion of the character of the drift, it is as much presumed that this factor has been eliminated as, in the discus- sion of an astronomical question, it is presumed that the error of refraction has been eliminated. To discourse upon the existence of such previously oxidized material, in a serious paper written for professional glacialists, at this date, has an archaic flavor. To presume that Professor Salisbury, who has done some of the most critical work that has ever been done upon residuary products and their contributions to the older drift, overlooked this factor in the study of the Delaware region, is a reflection upon the critic, rather than upon the work he criticised. I have discussed with Professor Salisbury upon the ground the pre-glacial factor in the sum total of oxi- dation presented. To presume that a geologist cannot dis- tinguish whether the aging of a pebble took place before or after it became a pebble, is to suppose that this department of geology is yet in a primitive condition. To assume that there are no criteria for distinguishing pre-glacial oxidation from post-depositional oxidation and to fail to see the applicability of those criteria to the region under discussion, and make use of them, is to condemn the whole work of whomsoever makes the assumption; for the evidence of post-depositional oxidation, weathering, degradation and aging in its several forms, is so perfectly clear and so completely demonstrative, that it should not fail to impress itself upon any observer who has even a moderate command of the discriminations which such a study necessarily involves. If any eritical student will examine the terminal moraine and the drift north of it, and the gravel train that leads from the moraine’s outer edge down through the gorge of the Delaware, on the one side, and will examine the higher terraces and their fluvial deposits and the drift scat- tered over the highlands, on the other, he will find clear and abundant evidence that the one is relatively young and fresh, and that the other is markedly old and that the two deposits cannot, by any rational interpretation, be made contempora- neous. That Professor Wright is in radical error, respecting the deposits of the Delaware Valley, is evident from the self-con- tradictory nature of his own interpretations. He refers the slack drainage deposits along the Delaware (Philadelphia Brick-clays, McGee’s Columbia) to the Champlain depression.* But he admits, what is incontestable, that after this epoch of slack drainage deposition there was an elevation during whieh were deposited the Trenton gravels, which he refers to a “time when the ice had melted far back towards the head * See this Journal, Nov. No., pp. 358, 366, 370, 371 and 372. See also, ‘‘ Man and the Glacial Epoch,” pp. 254-261; also, ‘Ice Age of N. A.,” pp. 522-527. T. C. Chamberlin—Diversity of the Glacial Period. 191 waters of the Delaware, and after the land had nearly resumed its present relations of level, if indeed, it had not risen north- ward to a still greater height.”* Now it is incontestable that it was after the ice had retired from the head waters of the Delaware, that the depression occurred during which the marine deposits of Montreal and the Champlain region were laid down. Professor Wright also states that between the deposit of the Philadelphia brick-clay and that of the Trenton gravel, there was a “long interval.”+ We, therefore, have Professor Wright referring to the Champlain depression deposits that were laid down long anterior to the Trenton gravels, which, in turn, were deposited at a time of elevation which, in its turn, was demonstrably early than the Cham- plain deposits. To refer the slackwater deposits of the Dela- ware and the marine deposits of the Champlain Valley to the same depression, and yet put between them a ‘long interval ” and a period of elevation, is a characteristic instance of the self-destructive interpretations to which the old doctrine of unity naturally invites. Besides the evident error of confounding two depressions, separated from each other by the acknowledged interval occu- pied in the erosion of the gorge of the Delaware and by the intervention of an elevation comparable to the present, there is a specific error in Professor Wright’s correlations. He makes the well-known gravel terrace at Trenton the correla- tive of a terrace of less than half its height at Yardville, a few miles above, overlooking the fact that terraces of the same nature and gradually rising altitudes occur at short: intervals all the way from Trenton to the Belvidere moraine. There they join the moraine in the characteristic fashion of moraine- headed terraces with which students of the high-gradient terminal moraines have become familiar. That this connec- tion is clear and demonstrative is the judgment of at least five geologists who have studied the formations. It is altogether probable that a complete analysis of the drift formations of the Delaware will develop some additional factors, and possibly extend its history, but the following feat- ures I think may be accepted as demonstrative : 1. That there was an earlier invasion of the ice which reached at least a dozen miles south of the Belvidere moraine. For present purposes it does not matter at all whether it in- eluded the High Bridge and Pattenburg deposits or not, nor whether the more distant drift is glacial or glacio-natant. 2. That there is an older fluvial deposit (the Philadelphia brick-clay) which is likewise much older than the Belvidere * “ Man and the Glacial Period,” p. 261. + ‘* Man and the Glacial Period.” p. 257. 192 7. C. Chamberlin—Diversity of the Glacial Period. moraine and which for the present is to be associated in age with the old glacial drift, though the two may not prove, upon further examination, to be strictly contemporaneous. 3. That after the formation of this older river deposit, which took place at a low altitude and low gradient, there was an epoch of elevation and of erosion, during which the Dela- ware cut its channel down to the depth of 200 to 300 feet below the upper old terrace. 4. That there followed a second incursion of ice which formed the Belvidere moraine, the over-wash of which ran down into this previously formed gorge and filled it up toa height of about 100 feet in the immediate vicinity of the moraine, and to progressively less and. less heights farther down stream until at Trenton the height had declined to about 40 feet. If Professor Wright were correct in his correlation of the terrace at Trenton, it would not affect, in any essential degree, the history here given, because the other terraces within the gorge above, some of them in the immediate vicinity of the moraine and in immediate connection with it, constitute the essential part of the evidence. I do not think that any geolo- gist, at all expert in these lines, can entertain any doubt as to contemporaneity of these terraces with the moraine, or that the gorge was formed antecedent to the moraine, or that the higher terraces, capped with the old gravels and clays, were formed earlier than the gorge; and I am surprised that any- one professing familiarity with drift phenomena, should ques- tion the markedly superior age of the old drift. The phenomena on the Delaware, therefore, taken in con- nection with those of the St. Lawrence and Champlain Val- leys, seem to admit of no rational interpretation, that does not involve two depressions and an intermediate stage of eleva- tion. The duration of the elevation has as its minimum measure the cutting of the river gorge and the high-gradient glaciation beginning with the Belvidere moraine and embrac- ing several subsequent episodes of undeterniined length. I conceive that there may be differences of judgment as to how much divisional value such orographie stages and such alterna- tions of action and such evidences of aging may be entitled to; but that here are tangible divisions of the glacial history of the region that are of fundamental importance in the interpreta- of the deposits and in the determination of the glacial rela- tions of supposed art relics, does not seem to me to admit of question. The phenomena on the Susquehanna are, so far as known, very closely similar to those upon the Delaware, but they have been much less fully worked out and may be passed over. T. C. Chamberlin— Diversity of the Glacial Period. 198 The phenomena upon the Allegheny, Upper Ohio and adja- cent rivers, seem to me to be in precise harmony with those of the Delaware. Before discussing them, however, I need perhaps to say a word respecting Professor Wright’s hypothesis regarding the effects of a supposed glacial dam at Cincinnati which, in his view, destroys the force of the data upon which I postulate an interval of deep river erosion between the earlier and later glacial invasions. In the first place it should be noted that, although nearly a decade has passed since the hypothesis was advanced, no out- let for the great hypothetical lake has been found, though it has been called for as the necessary credential of such an hypothesis. Such an outlet must, in the nature of the case, be a marked phenomenon. s It is to be noted, in the second place, that the decisive facts brought out by Mr. Leverett with reference to the white silts which spread over the drift north of the Ohio throughout the whole reach of the supposed dam, destroy one of the chief arguments for the hypothetical lake above the supposed ice dam, and this holds true when the dam is given the greatest extension assigned it by Professor Wright. It will be borne in mind that Professor Wright appeals to the silts of Beech Flats as evidence of a lake caused by the dam. Mr. Leverett has shown that these are but a part of an extensive sheet stretching westward over the very area occupied by the ice supposed to have formed the dam, reaching even to and _ be- yond its western border, covering wide areas in southwestern Ohio, northern Kentucky and southeastern Indiana. Mr. Leverett’s language is clear and covers the whole ground; it is as follows: “‘ Not only are the clays of these two localities [Beech Flats, Pike county and the till area, Highland county, Ohio] “ simi- lar in macroscopic and microscopic aspect, but they form a practically continuous sheet extending from the Beech Flats and adjoining lowlands outside Wright’s glacial boundary west- ward onto the glaciated districts of southwestern Ohio, north- ern Kentucky and southeastern Indiana, occupying the site of the hypothetical Cincinnati ice-dam and showing as strong development below (west of) the site of the supposed dam as they do above it. The fact that these clays cover a part of the glaciated district proves that their deposition occurred subse- quent to the time of maximum glaciation, and their distribu- tion shows that the ice-sheet nowhere reached the Obio river while they were being deposited. It is evident, therefore, that their deposition cannot be attributed to an ice-dam on the Ohio at Cincinnati or any point below.’’* * Am. Geol., vol. x, July, 1892, p. 21. 194 7. C. Chamberlin— Diversity of the Glacial Period. Prof. Wright strives to elude the force of this by the following statement : “Mr. Leverett in particular has attempted to correlate some of the clay and lcess deposits in southeastern Indiana, with deposits of similar character in Illinois, attributing both to the earlier Glacial period during its slackened drainage. But he does not seem to have duly considered the faets which I have presented making probable an obstruction of the channel of the Ohio near Madison, Indiana, in Jefferson and Ripley counties which might well account for the facts in that part of the State most like those in southern Ohio. (See Bull. U.S: Geol. Surv., 58, pp. 65, 66.) Something more than similar microscopical results must be relied on to demonstrate chrono- logival identity of deposits.’”’* ‘In Prof. Wright’s own language, “A theory driven to such extremities cannot be said to be altogether free from diffi- culty.” + Prof Wright thus explains the discovery of these Beech Flat silts: “So confident have I become in the reality of this dam that I have not hesitated to use it as a means of putting myself in the line of discovering other facts which are the natural consequence of this. Many of the facts enumerated in this paper (as, for example, those connected with the head- waters of Brush Creek) were thus discovered. It was reasoned that they must exist from the nature of the supposition ; and upon examination in proper localities it was found that they did exist according to previous calculation. I need not say that such experience is the most convincing proof of a theory.’ t The succession of deposits even in this region on which such large conclusions have been staked, and which I therefore touch incidentally, is very significant. There is here (1) a till sheet with an attenuated edge reaching across the Ohio into Kentucky for a few miles, (2) an interval of deglaciation indi- cated by a soil horizon at the surface of this sheet, (8) a silt deposit overlying this and indicating a period of slack or still- water deposition, and (4) a till sheet edged by a terminal moraine, from the outer side of which there was free vigor- ous drainage, as shown by moraine-headed terraces of gravel. At two localities these silts have been seen beneath this later drift, and there is much indirect confirmatory evidence of this relation. These facts indicate an interval between the two during which occurred the change from conditions of silt * This Journal, Nov., 1892, pp. 369-370. + Ibid., p. 371. Where this sentence is used by Prof. Wright it has no pertinency whatever, as Mr. Leverett’s suggested hypothesis to account for the unusual depths of the rock channels near the border of the drift stands wholly by itself. t Bulletin 58, U. 8. Geol. Surv., p 10). T. C. Chamberlin—Dwersity of the Glacial Period. 195 deposition over the country generally to conditions of free drainage pouring down through valleys cut to considerable depths below the silt horizon (Leverett). In this region, therefore, between the border of the drift and the outermost moraine there is decisive evidence of a till- depositing period, an interval of soil formation, a silt-deposit- ing period, an interval of radical drainage-change and a moraine-producing advance of the ice. This is a very different collocation of formations trom that which seems to be implied by Prof. Wright’s language (pp. 353-356 and 357). It is very far from being a simple moraine-and-“ fringe ” combination. In Eastern Ohio and Western Pennsylvania the outer mo- raine runs much nearer the attenuated border of the old drift and the intervening silts are obscure or absent, or confined to the remnants of the old base levels, so that it is not so surpris- ing that the vanishing edge of the old drift should here be mistaken for a dependency of the outer terminal moraine, but that the relationship is really the same as it-is demonstrably to the westward, I hold to now be beyond serious question. These points bear upon the explanation of the glacial gravels that le upon the high terraces in the Allegheny and adjacent valleys. These terraces I have maintained (Bulletin 58, U.S. Geol. Surv., pp. 20-38) were produced at a time of base level degradation, which in its later stages was contemporaneous with the earlier ice incursion whose waters bore gravels down the Allegheny, Upper Ohio and some adjacent streams, and formed the 40 or 50 feet of capping which lies upon the rock benches that constitute the body of the terraces. I have argued that subsequent to this the land was elevated and the lower newer steep-sided gorges of the Allegheny and neigh- boring streams were cut to a depth that may be roundly stated as 250 feet, and that subsequent to this the later ice incursion formed the outer moraine of the region. From the outer side of this moraine glacial streams bore their sands and gravels down the Allegheny gorge cut during the interglacial inter- val. The evidence of this, gathered in a joint study by Mr. Gilbert and myself, may be found in Bulletin 58, U.S. Geol. Surv., pp. 32-36. I therefore argue that between the time when the glacial gravels were deposited on the high terraces and the incursion of the later ice there was a cutting of the gorge to the depth of 250 feet roundly speaking. I regard this gorge-cutting as a minimum measure of the interval be- tween the two ice incursions. Prof. Wright does not admit the force of this evidence because he interprets the occurrence of the glacial gravels on the high terraces as the work of ice floating from the edge of the glacier on the surface of the hypothetical lake formed by the supposed Cincinnati ice dam. 196 7. C. Chamberlin— Diversity of the Glacial Period. He now admits, what I have not understood him to do before, that the terraces, so far as they are rock, are due to base-level- ing, but that the glacial gravels deposited upon them are due to floating ice. To the latter part of this view, there seem to me to be two fatal objections. In the first place, I think it is entirely foreign to observation, as well as to a@ prior? considera- tions, to suppose that floating ice would produee, in the aban- doned bends of old rivers surrounded by hills, and upon rem- nant shelves along the sides of the valley, fine stratified gravels bearing every aspect of river deposits. Under the conditions postulated a very different class of deposits should be formed. Besides, the deposit should have been practically uniform over the whole bottom of the supposed lake, and not simply confined to the old terraces. In the second place, these terraces rise in altitude toward the headwaters of the river until some of them are considerably higher than the sup- posed ice dam, notably those at Warren, Tidioute and Oil City, which are respectively 1395, 1390 and 1270 feet above tide, while the height assigned for the dam is 1000 or 1100 feet. (See Bulletin 58, U. S. Geol. Surv., p. 27.) Aside from these definite and tangible factors, the whole aspect, association and relationship of these formations make them river deposits and exclude them from the distinctive lacustrine class. In admitting to his hypothesis the factor of base-leveling, Prof. Wright has relinquished the last remnant of occasion for postulating his ice dam, for all of the phenomena ap- pealed to are the natural incidents of base-leveling. Stretches of slack water, which are inevitable when a river reaches the base-level stage and begins to build up its bed, furnish deposits indistinguishable from those of lakes; indeed lakes form in the abandoned channels of the stream. So also base-leveling and the resilience from it involve the transfer of the position of low divides which lie near the upper limit of the base plain, the transfer being from the side of the shorter or easier course toward the longer or more obstructed course. The trans- ferred divide is carried into the bottoms of the stream whose territory is invaded, so that its former flood plain deposits be- come the new divide; and hence the phenomena of slack water deposits on some of the present divides become, under the hypothesis of base-leveling, precisely what is to be ex- pected. These may occur at altitudes greater than the base plain’ of the main river. These and coordinate methods of action cover all the phenomena for the explanation of which the supposed ice dam was brought into requisition. Being left thus without a raison detre, being robbed of all support from the Beech Flat silts, and being entirely without T. C. Chamberlin—Diversity of the Glacial Period. 197 the necessary support of a recognizable outlet, the hypothetical lake may well be dismissed from the literature of the subject. The whole phenomena fall into perfect consonance with the phenomena of the Delaware and Susquehanna. As one of the strong, and as it seems to me, unanswerable arguments in favor of a considerable interval between an earlier and a later drift formation, I appeal to the cutting of the Delaware gorge 200 feet or more, which was demonstrably later than the high terraces bearing glacial silts and gravels and demonstrably earlier than the Belvidere moraine from which a gravel stream was poured down into the gorge cut during the interglacial interval. I make a like appeal to a sim- ilar class of phenomena on the Susquehanna, and I repeat the appeal in respect to the precisely analogous phenomena of the Allegheny and other tributaries of the Upper Ohio, and the upper part of the river itself. I make a similar appeal to the erosion of the lower Mississippi valley and several of its branches, the erosion here however sustaining a different rela- tion to the old erosion plane. Doubtless the appeal could be made to all branches if the import of the phenomena were equally clear in all cases, or had been equally studied. The form which the valley erosion took and the material eroded varied with the antecedent and concurrent conditions which were not the same in all valleys, nor the same in all parts of the same valley, but a correspondent erosion occurs on all branches that have been carefully studied so far as I am in- formed. All this class of phenomena repeating itself over and over from the Atlantic to the western plains, carries a force from which I think there will be found no escape when the phenomena are critically and judicially investigated. But the case does not rest upon the interglacial cutting of these. river channels alone. It is supported by concurrent erosion over the whole surface of the old drift. If there were any error in the interpretation of the river channels it would be shown in the facies of the old drift. But its topography shows an amount and kind of erosion that indicates similar antiquity. The phenomena are so wide spread that special enumeration is wholly impracticable. Ina paper on the Drift- less Area, Prof. Salisbury and myself attempted a careful description of a part of these erosion features and drew a com- parison between them and those of the new drift. There, it is to be noted, the two borders were subject to the same condi- tions save that of age. One of the best fields for a comparison between the fresh little-eroded topography of the later drift and the much-eroded topography of the earlier drift, is found on the borders of the tongue of the later drift which terminates at the capital of 198 7. C. Chamberlin—Diversity of the Glacial Period. Iowa. The surface within the moraine loop has suffered very slight erosion, except in the vicinity of the streams. Even the channelings of these are sharp-sided and ditch-like. Over the surface shallow sags, without outlet, occur in extraordinary abundance. They are to be numbered rather by tens of thou- sands than by thousands. On the old drift outside of the loop an erosion surface of pronounced type is presented. A com- plete erosion topography has been developed and has sunk itself deeply below the original surface. To appreciate this contrast let any one make a circuit of one hundred miles north from Des Moines upon the later drift, and he will find, throughout, indisputable evidence of freshness and recency. Let him then make a similar circuit of one hundred miles west, south and east on the area of the old drift and he will find a rolling surface with undulations reaching up to 80 feet and more of perfectly characteristic dendritic erosion topography, and upon examination of the stratified portions of the drift he will readily be convinced, if a topographic geologist, that this erosion supervened upon the formation of the drift. On the summits of this rolling land he will find the loess-like silts that cover so much of the earlier drift. Modern topographic sci- ence goes for naught, if evidences of this kind do not signify a prolonged interval between the deposit out of which such an erosion surface has been carved, and the immediately adjacent deposit upon which so little carving has been done. To this combination of general erosion and of channel cut- ting, there are to be added evidences of like import from oxi- dation, ferrugination, decomposition and other characteristic forms of weathering. These, in the hands of an expert com- petent to eliminate preglacial and englacial factors, bear testi- mony of great value. The value is certainly almost wholly dependent upon the circumspection, skill and conscientious- ness with which the criteria are applied, but the value is none the less real. When these evidences are found, as in this case, concurrent with general surface erosion and with the special erosion of river gorges, the combination has a value much beyond either factor alone. When to this is added the fact that the drift sheets most eroded and most oxidized, are those which were deposited at low-gradients and without ero- sion advantages at the start, and that in general, they lie in regions that are now lower than the less eroded drift of later date, the case is still further strengthened. When, to the combination, there is also added the fact that the deposition of this low-gradient, now much-eroded, much-weathered deposit, was separated from that of the fresher, little-eroded sheet by an elevation of the surface and an increase of slope which gave a markedly more vigorous drainage, and the still further fact T. C. Chamberlin— Diversity of the Glacial Period. 199 that the interval is emphasized by notable vegetable accumu- lations, and supported by the strong analogy of the Great Basin phenomena, the whole combination takes on a strength which seems to me altogether irresistible. While the evidence from plant and animal remains found in the interglacial beds in America has not yet reached a full- ness and definiteness which render it altogether decisive regard- ing the climate of the interglacial intervals, though it indicates something less than a glacial climate, the evidence of this class in Europe, a summary of which is given by Dr. Geikie in the paper already referred to, appears to me entirely decisive, unless the integrity of the observations can be overthrown. The demonstration of a climate in Northern Europe, compar- able to the present, seems to carry with it the necessary con- clusion that glacial conditions were essentially as remote then as now. It seems to me idle to cite the fact that temperate faunas and floras now exist in the vicinity of glaciers within the temperate zone, for these are mere local phenomena and do not stand related to the general climate of the region, as the great ice sheets of glacial times must have done. The fossil evidence of the acknowledged glacial epoch shows Arctic con- ditions. On the same basis of reasoning, a temperate fauna and flora show the absence of glacial conditions. When, therefore, to the strong cumulative physical evidence - in America and the similar physical evidence in Europe, there is added the array of organic evidence that has now grown large, it seems to me the case approaches demonstration, so far as the general fact of a great interval or intervals is concerned. To fail to accept this, at least as a working classificatory basis, is to do violence to the highest mterests of science. The history of this question I apprehend, will be very analo- - gous to that of paleontological research. In the earlier stage, investigators were satisfied with very general delineation and rude groupings of forms. But, with the progress of the sci- ence, more and more critical scrutiny of likenesses and differ- ences was found requisite, and closer and closer specific and varietal distinctions were drawn. This tendency at length became excessive and the multiplicity of divisions was pushed beyond the actual phenomena. The enlargement of collec- tions then began to bring together many species by inter-gra- dations, and the elimination of false species resulted. But yet certain species stand clearly differentiated from all other species and unquestionably will continue to stand. The gaps between them can only be filled by tracing them far back in geological time. So I think it may be with the divisional effort in the glacial field. We are very likely to push differentiation to excess in the stage we are now approaching, and to recognize 200 Ludeking and Starr—Specific Heat of Ammonia. for a time, episodes of glaciation that are not widely sep- arated from their neighboring episodes. But this will be wholesome for the time, just as species-making was. It is, in deed, almost necessary to the ultimate end sought to make the sharpest possible discriminations, even if they result in excessive divisions which shall last only until such time as they may be brought together by interstitial formations. Although not fully placed before the public, at least four divisions of the drift south of the Great Lakes are now being employed as working hypotheses and are gaining strength under the tests of the field. The interval I have chiefly dis- cussed in this paper is the middle one. I have regarded it as the most important one, possibly the only one that will ulti- mately stand as possessing an epochal value, but I am in sym- pathy with the movement led by Dr. Geikie, because it will develop a more precise delineation of the history of glaciation. If the terminal moraines of Ontario have much divisional im- portance, they will make the present working classification of of this country closely analogous to that advanced by the dis- tinguished Scotch glacialist. It is the present judgment of the majority of critical work- ers in both the American and European field, that amid all future tests two or more of these divisions at least will stand as well sanctioned epochs, to whatever grade others may be relegated by the fuller knowledge of the future. Art. XXIV.—The Specific Heat of Liquid Ammonia; by C. LuDEKING and J. E. STARR. THE specific heat of liquid ammonia, though it has often been the subject of calculation in development of theory and practice, has not yet been satisfactorily determined experi- mentally, if we except the work of Regnault. His results, however, were unfortunately lost during the Paris Commune. He assumed the specitic heat to be 0°799. Since then the interest in this constant has very. considerably increased through the rapid development of the artificial ice industry. Generally the specific heat has been taken at unity. Thus DeVolson Wood in his “ Thermodynamics,” page 837, recom- mends this value “ until the experimental value is determined.” It was our good fortune to have ready access to all the means necessary for executing the somewhat laborious experi- ments involved and we take this opportunity to present briefly Ludeking and Starr—Specific Heat of Ammonia. 201 the results of our work. The liquid ammonia used in the experiments was found on examination to contain 0°3 per cent of moisture and on spontaneous evaporation to leave only a trace of residue. The impurities were therefore of no conse- quence in influencing the result to the limit of accuracy intended. Of this liquid ammonia 10:01 grams were introduced into a small steel cylinder of 16°122° capacity, stoppered by a steel screw. The mode of filling was quite simple. After cool- ing the cylinder in a bath of the liquid ammonia itself and while still immersed it was possible to pour it brimful by means of a beaker. The steel screw stopper, also previously cooled, was then inserted and drawn almost tight, On then removing the cylinder from the cooling bath the liquid con- tents gradually expanded and escaped in quantity proportional thereto and besides a very small vapor space was allowed to form as is indicated in the experimental data. Then the stop- per was driven tight. Thus the error in the result, due to the latent heat of condensation of vapor of ammonia in the course of the experiments was reduced to a minimum and rendered, as will be seen, almost inappreciable in its influence. The cylinder was perfectly free from leakage and remained constant in weight during each series of determinations. It was suspended in the drum of a Regnault apparatus heated by the vapor of carbon disulphide. The entire mode of pro- cedure was in all details that commonly used in the Regnault method. After the cylinder had been heated for about six hours it was dropped into a brass calorimeter whose water value was 1°36 cal. and which contained 150 grams of water. In each experiment it required very nearly two minutes to raise the calorimeter to its maximum temperature. The influ- ence of loss by radiation was reduced to a minimum by the Rumford manipulation. The thermometers used were stan- dardized, carefully compared and read to hundredths of a degree by means of a magnifying lens. The experiments were conducted sufficiently far from the critical temperature, which, according to Vincent and Chappuis is 131° C. The following are the data of Experiment IL: Weight of steel cylinder and ammonia__--- 81°008 grams. Were htotestecleylinderm ss a 4a2 2.62 1 MO 998 sire Wiero htpofsammoniae a= = ase e ee eon ane) 10°01 The specific gravity of liquid ammonia being 0°656, the volume of 10-01 grams is 15:26°. 202 Ludeking and Starr—Specifie Heat of Ammonia. Total water value of calorimeter, thermometer and ‘water-'22 222222 SS 2o Se ee mes Water value of steel cylinder __.--.------- 8°34 cal. Temperatureiofair, S222 sens eee ae obs -45G: Temperature of steel cylinder__<- -_ =22. 2255" 46>-51@: Temperature of calorimeter after immersion, 26°69 C. Calorimeter before immersion ------------- 24°44 ©, Nisengtemperatures- p= ee 2°-25 C. Thus 341-46 cal. were given off by the cylinder in cooling 19°-82 or 17°23 cal. for one degree. Of this 8°34 cal. are due to the steel cylinder itself, leaving 5:89 cal. for 10-01 grams of liquid ammonia or 0°888 per gram = specific heat. In a sec- ond and third experiment the values 0-897 and 0°896 were obtained. The determination of the specific heat of liquid ammonia would be influenced, as stated, by the latent heat of condensation of part of the small quantity of vapor present, when the cylinder cools in the calorimeter. This would to a degree be neutralized by the contraction of the liquid ammonia itself in the cooling and the consequent formation of more vapor space. It seemed desirable to ascertain the influence of these factors collectively by experiment. For this purpose specific heat determinations were made in a way somewhat different from the ordinary. The steel cylinder was cooled in an iron shell in melting ice, instead of being heated, and then introduced into the warm calorimeter water. The mode of procedure was in detail similar to that described above and we will there- fore only give our results. In three experiments the values 0°878, 0°863, and 0°892 were obtained. ‘They are a trifle lower in their average than the results obtained by the ordinary method. It is reasonable to assume that they are somewhat low, while as stated the other results are presumably some- what high and in order to arrive at the specific heat of this substance nearest the true value from our experimental evi- dence, we will take the average of our six values, viz: 0-888 0°878 0°897 » 1st series. 0°863 » 2d series. 0°896 0°892 and state it as being = 08857. We beg herewith to acknowledge our obligations to Chan- cellor W. S. Chaplin and Prof. Wm. B. Potter for kindly placing the laboratories under their charges at our disposal. Cove Mills, Stamford, Conn. NV. H. Darton—Oneonta and Chemung Formations, etc. 203 Art. XXV.—The stratigraphic relations of the Oneonta and Chemung formations in eastern Central New York; by N. H. Darron, U.S. Geological Survey. Introductory.—This paper is a condensed account of a recent investigation in upper Devonian stratigraphy, made for the State of New York for the new geological map. Dr. James Hall made some statements regarding the general bearing of the results at the Rochester meeting of the Geological Survey of America, and a detailed report with map will finally be published in the report of the State Geologist of New York. The principal purpose of the investigation was to determine the relations and distribution of the Oneonta and Chemung formations in their extension from Delaware county through the Catskill Mountains, but some study was also given to their relations in Chemung and Broome counties. In its typical development in Otsego county, the Oneonta formation comprises a thick mass of red shales and red and gray sandstones similar in character to the rocks of the Catskill Mountains and overlying the Chemung formation in southern New York and northern Pennsylvania. The formation was given its name by Vanuxem who supposed that it was equiva- lent to the Catskill formation and above the Chemung forma- tion. The organic remains in the Oneonta beds were few and consist of plant remains common to the Catskill rocks and a fresh or brackish water form now known as Amphigenia. Later studies by James Hall and others led to the discovery of an overlying series of shales and sandstones containing Che- mung fossils at several localities southwest of Oneonta, and it was found that the fauna of the underlying beds was Hamil- ton in age. ‘These discoveries indicated that the Oneonta for- -mation represented approximately the eastern extension of the Portage formation, considerably modified in character but well defined in stratigraphic position. Nothing however was deter- mined as to the eastward extension of the Oneonta beds and overlying Chemung along the northern and eastern side of the Catskill Mountains and Mather’s statements in his report were too vague to throw light on the problem. The great mass of gray sandstone with red shales constituting the Catskill Moun- tains were designated Catskill by Mather and the mass was supposed to be underlain in eastern New York by an obscure, attenuated representative of the Chemung and under which in turn were recognized the ‘“ Portage” and the Hamilton formations. AM. JouR. So1.—THIRD Series, Vou. XLV, No. 267.—Magcn, 1893, 15 204 “W339 JIYVHOHOS |): 11 i aly N. H, Darton—Oneonta and Chemung f —————S i —= PORTAGE: GRAY SHALES FLAGS « CONGLOMERATE 9200000 SANOSTONE wii! 6000 feet. Fig. 1.—Horizontal scale, 1 inch = 16 miles; vertical scale, 1 inch = I began my studies at Oneonta and measured an instrumental section south- ward past Franklin. From this I worked eastward to the eastern front of the Cats- kill, and westward to the latitude of Binghamton. General results. —'The accompanying sections are intended to illustrate the general relations : . Fig. 1.—Section from central Broome County, eastward through the Catskill Mountains nearly to Catskill. It may be seen in these sections that the Oneonta formation continues east- ward with gradually increasing thickness and comprises the lower thousand feet of beds in the Catskill Mountains. Its characteristics are unchanged and its stratigraphic limits are distinct through- out. Westward its red beds gradually merge into the thin-bedded sandstone and hard dark shales of the Portage and disappear entirely between Norwich and Cortland; the red material extending farthest west in the highest beds. The thin series of gray shales and fine- grained sandstones, with Chemung fos- sils, overlying the Oneonta formation about Franklin, southwest of Oneonta, are the basal beds of the great mass of fine grained sediments which constitute the Chemung formation in southwestern New York. They are overlain by seve- ral thousand feet of hard, coarse, cross- bedded gray sandstones with intercalated red shales and gray flags into which they merge eastward and at the expense of which they expand westward. This merging was studied with great care and it was found that stratigraphic continuity throughout is beyond question. There is no overlap or wedging out of the beds either as a whole or singly but a gradual transition of coarse materials into fine materials. Lower and lower shaly beds are successively involved eastward until at a point about due south of Oneonta Formations in eastern Central New York. 905 the lowest beds of shale finally merge into hard, coarse-grained, eross-bedded gray sandstones which then extend eastward through the Catskill Mountain immediately above the Oneonta formation. Westward the shales with Chemung fossils attain a thickness of about. six hundred feet near Susquehanna, bed after bed of sandstone becoming finer grained and _ finally merging into shale of soft fine grained sandstone. This change of character continues to ascend in horizon westward through southern central New York and northern Pennsyl- vania, until according to Sherwood,* Chemung fossils are found within one hundred and fifty "feet of the base of the Lower Carboniferous, nearly a thousand feet above the begin- ning of red beds in that region. A B C D CATSKILL GROUP HAMILTON GRP DARK SHALES FLAGS SSS —S > SANDSTONE #22822 REDSHALES= = Fig, 2.—A, section through Susquehanna; B, through Oneonta and Frankhn ; C, Schoharie Creek ; D, West of Palenville (C, D, Catskill Mts.). Seale, 2,000 feet to the inch. Fig. 2.—Columnar sections at intervals along the same line as the section in figure 1, to illustrate the prominent variations in stratigraphy. From these statements it is evident that the great mass of coarse sandstones with red shale intercalations in the Catskill Mountains gradually changes westward into fine grained sedi- ments with Chemung fossils, the change beginning in the basal beds just above the Oneonta formation in northern cen- tral Delaware County. The Oneonta formation is character- *2d Geological Survey of Penn.; Report on Bradford and Tioga Counties, G. Harrisburg, 1878. 206 NV. H. Darton— Oneonta and Chemung ized by a greater proportion of red shales than are contained in the great overlying series eastward, but both are closely related in their general history. The Oneonta beds preserve their character for a few miles farther west than do the basal members of the overlying series, but finally merge into typical Portage. The Hamilton group (Marcellus to Hamilton) also change in character eastward similarly becoming coarse-grained and finally flagey nearly to its base. The outcrop area of the typical Oneonta formation is a wide belt extending through eastern Chenango, southern Otsego, northern Delaware, southern Schoharie and eastern Greene counties. . Its oreatest width is on the latitude of Otsego where the belt is about fifteen miles wide. In Delaware county it averages from six to ten miles wide and its beds are everywhere finely exposed. On Schoharie Creek it begins at the Manorkill Falls and extends about twelve miles southward, It extends far north about the headwaters of the Catskill and then southeastward in a narrowed belt along the steep slope of the high northern and eastern front of the Catskills Dy Cairo and through Palenville. Stratigr raphy. —The stratigraphic components of the Oneonta formation are somewhat variable in its smaller subdivisions but certain members preserve general characteristics throngh- out. The basal beds are gray flags which merge into the Hamilton. Their thickness averages about fifty feet and they may be regarded in greater part as beds of passage. They are streaked with red shale above and give place to a thick mass of red shales with more or less intercalated gray or greenish flags. Next above is a series of gray sandstones and flags with occasional red shale streaks in some localities, and usually some red sandstone layers. This series averages between two hun- dred and two hundred and fifty feet in thickness. The upper member of the formation consists of six or seven hundred feet of red shales and sandstones with intercalated gray and green- ish flagey beds and some cross-bedded sandstones eastward. The red shales are bright red in color and moderately hard in texture. They are not in regular continuous beds throughout but constitute greatly elongated lenses in the gray flags and red sandstones. Toward the western termination of the Oneonta formation these members lose their distinctness and finally give place to the gray beds of the Portage. The formation also gradually decreases in thickness and width and on the Chenango there are not over 500 feet of red beds. West of Norwich the red materials disappear rapidly and their place is taken by gray shales and thin bedded sandstone. ‘This change in character is Formations in eastern Central New York. » 207 from below upward, going west, and there can be no doubt as to the continnity of sedimentation throughout. South of Cortland the red materials are entirely absent and the entire section is typical Portage. The fossiliferous Chemung shales overlying the Oneonta formation south of Franklin have a thickness of about 309 feet and present the usual Chemung character. They grade up- ward through a series of flags, into hard, coarse, cross-bedded gray sandstones with intercalated red shale layers. In tracing these fossiliferous shales eastward they were found to gradually merge into flags and then into harder, coarse sandstones until at Croton, ten miles east, their horizon is represented by a heavy mass of coarse, gray, cross-bedded sandstones with flaggy layers. This mass becomes harder and coarser eastward and was traced to and along the eastern front cf the Catskill Mountains, its base defining the upper limit of the Oneonta formation. Its thickness averages about 250 feet. It is over- lain by a red shale bed twenty-five to thirty feet in thickness and this in turn is overlain by the thick mass of hard gray sandstone on which the old Mountain House is built. Ata point about four miles due west of Durham some mollusean remains were found in a softer gray bed about 175 feet above the summit of the Oneonta formation. One fairly distinct individual was recognized by Dr. Hall as Spirifer disjuncta, a Chemung form. From Franklin, westward, the Oneonta-Chemung boundary is clearly marked by the abrupt change from red beds to gray shales and soft sandstones. It extends along the slopes south of Unadilla and Sidney down the Susquehanna to a couple of miles below Afton. Thence south to Guilford and Summit on the New York, Ontario and Western Railroad and down the Chenango to Greene. The exposures along the railroad opposite Oxford from Lyons Creek bridge, where the Hamil- ton is exposed, to the Chemung at Summit, were described by C. E. Beecher, J. W. Hall and C. E. Hall as a typical section exhibiting the stratigraphic position of the Oneonta forma- tion.* I have not traced the formations farther southward than Palenville along the eastern front of the Catskills but there ean be no doubt as to their extension across the Delaware and far into Pennsylvania. The “Chemung” rocks to which Mather and others refer, lies below the Oneonta beds or about 1,000 feet below the actual base of the Chemung horizon, and are Hamilton in position. Their fauna is meager and consists of species sup- posed by Vanuxem to be “ Chemung” in central New York, * Note on the Oneonta Sandstone in the vicinity of Oxford, Chenango County, 5th Report of State Geologist of New York, for 18835, p. 11. 208 WN. H. Darton—Oneonta and Chemung Formations, ete. but now known to be Hamilton. Mr. C. 8S. Prosser* in a recent paper on the Devonian system of eastern Pennsylvania, de- scribes the relations along the Delaware, Lackawanna and Western Railroad in Monroe County west of Stroudsburg and shows that Hamilton fossils occur up to the base of the red beds which have heretofore been considered ‘“ Catskill” in age. It is probable that these basal red beds to which he refers will be found to be Oneonta for the first 1,000 feet or more, with the overlying Chemung indistinguishable, as in the Catskill Mountain region. The status of the name “ Catskill.’—Catskill has been used as a geologic designation with such variable stratigraphic sig- nificance that its status as a formation name is worthy of serious reconsideration. No one can fail to be impressed with this who reads Prof. Stevenson’st admirably clear and exhaus- tive review of upper Devonian stratigraphy, or has followed the various controversies on the geology of southern New York and northern Pennsylvania. The typical ‘“ Catskill” region is of ' course the Catskill Mountains and in this region the name was intended to comprise all of the great mass of gray sandstones and red shales up to the base of the doubtful conglomerate capping the higher summits. Rocks of this character overlie the fossiliferous Chemung shales westward, and it has hereto- fore been supposed in the Catskill Mountains that they were similarly underlain by representatives of the Chemung. This as I have found proves to have been a mistake and the red and gray rocks of the Catskill Mountains—the type locality— comprise not only the Chemung but also the Portage horizons. The term Catskill has been applied in the past to beds of a certain lithologic character—the hard sandstones and red shales—and it has had no definite stratigraphic significance. This fact has been realized in the case of the upper members westward, but the determination of the true stratigraphic range in the Catskill Mountains throws additional light on the matter. The rocks of the Catskill Mountains, and beds of similar character westward, have no distinctive fauna of stratigraphic significance and they cannot be correlated on paleontologic grounds. The lowest red beds have often been used as a eri- terion of discrimination between Chemung and Catskill, but they vary in stratigraphic position from the upper beds of the Hamilton in eastern New York to near the base of the Lower Carboniferous in northwestern Pennsylvania, a differ- ence in horizon of several thousand feet. The Chemung * This Journ., III, vol. xliv, pp. 210-221. + Address of Vice-President, ‘‘The Chemung and Catskill (Upper Devonian) on the eastern side of the Appalachian Basin, Am. Assoe. Adv. Science, Proc., vol. xl, pp. 219-247. W. Upham—Estimates of Geologic Time. 209 fauna is distinctive as a whole and it pervades the greater mass of the western extension of the rocks of the Catskill Mountains from the upper part of the Portage in western New York nearly to the Lower Carboniferous in northwestern Pennsylvania. As the ‘“‘ Catskill” in its type region comprises Portage and Chemung, my proposition now is to discontinue the use of Catskill as a coordinate formation term and use the term Cat- skill group to include the Portage and Chemung formations, the latter extending to the base of the Lower Carboniferous. I believe the Chemung and Portage are formations distinctly separable over a wide area, but Chemung and “Catskill” as formations are only separable by a lithologie distinction which progressively varies several thousand feet in stratigraphic posi- tion in the extension of the beds across southern New York. Stevenson, in the review alluded to above, points out the general unity of the upper Devonian throughout the Appa- lachian region, and as its marine fauna is predominately Che- mung, proposes the “ Chemung” asa period name to comprise three epochs; the Portage, the Chemung, and the Catskill. The new light on the stratigraphic range of the formation comprised under the name “ Catskill” in its typzcal region is the ground for my preference for the older term in its origi- nal significance, even though its true stratigraphic limits were not originally defined. Art. XX VIL.—AE#stimates of Geologic Time; by WARREN UPHAM. [Abridged from a paper in the Bibliotheca Sacra, Jan., 1893. ] AccorRDING to Sir Archibald Geikie, in his presidential address before the British Association last August,* the known rates of deposition of sediments imply that for the formation of all the stratified rocks of the earth’s crust a duration some- where between 73 millions and 680 millions of years must be required. Most geologists, before specially looking into this subject, would doubtless regard the lowest of these estimates as a minimum of the time needed for the processes of deposi- tion and of erosion revealed by their study of the rocks, and for the concurrent changes of the earth’s floras and faunas from their beginning to the present time. But to some geolo- gists, these figures seem far too small, among whom Mr. W. J. McGee, in a paper read before the American Association the * Nature, Aug. 4, 1892, vol. xlvi, pp. 317-323. 210 W. Upham—Estimates of Geologic Time. same month,* reasoning from similar prernises of geologic observations, would claim about seven thousand millions of years as the more probable measure of the part of the earth’s duration since its earliest fossiliferous rocks were formed, and probably twice as long time since the earth began its planetary existence. On the other hand, the most eminent writers who have con- sidered this subject from the standpoint of physical experi- ment and theory and their relationship with astronomy, including Thomson, Tait, Newcomb, Young, and Ball, tell us that geologists can be allowed probably no more than 100 millions of years, and perhaps only about 10 millions, since our earth was so cooled as to permit the beginning of life upon it. It is comparatively easy to determine the ratios or relative lengths of the successive geologic eras, but is confessedly very difficult to decide beyond doubt even the approximate length in years of any part of the records of the rock strata. The portions for which we have the best means of determining their length are the Glacial and Recent periods, the latter extending from the Champlain epoch, or closing stage of the Ice age, to the present time, while these two divisions, the Glacial or Pleistocene period and the Recent, make up the Quaternary era. If we can only ascertain somewhat nearly what has been the duration of this era, from the oncoming of the Ice age until now, it will serve as a known quantity to be used as the multiplier in the several ratios for giving us the approximate or probable measures in years for the recedingly earlier and far longer Tertiary, Mesozoic, Pale- ozoic, and Archean eras, which last takes us back almost or quite to the time when the cooling molten earth became first enveloped with a solid crust. Sir William Thomson (now Lord Kelvin) long ago estimated, from his study of the earth’s internal heat, its imcrease from the surface downward, and the rate of its loss by radiation into space, that the time since the consolidation of the surface of the globe has been somewhere between 20 millions and 400 millions of years, and that most probably this time and all the geologic record must be limited within 100,000,000 years.t Prof. George H. Darwin computes, from the influence of tidal friction in retarding the earth’s rotation, that probably only 57,000,000 years have elapsed since the moon’s mass was * Am. Anthropologist, Oct., 1892, vol. v. pp. 327-344. with a plate showing relative durations of natural time units, historical eras, and geologic periods. + In an article published two months ago in this Journal, since the present paper was written, Mr. Clarence King, from recent physical investigations of diabase when subjected to great heat and pressure, concludes that the age of the earth, deduced by Lord Kelvin’s method, is approximately 24,000,000 years. W. Upham—Estimates of Geologic Time. 211 shed from the revolving molten earth, long before the forma- tion of its crust. From the same arguments and the rate at which the sun is losing its store of heat, Prof. Guthrie Tait affirms that apparently 10,000,000 years are as much as phys- ical science can allow to the geologist. Professor Neweomb, summing -up the results of these physical and astronomical researches, writes: “If the sun had, in the beginning, filled all space, the amount of heat generated by his contraction to his present volume would have been suflicient to last 18,000,000 years at his present rate of radiation ..... 10,000,000 years . Is, therefore, near the extreme limit of time that we can suppose water to have existed on the earth in the fluid state.” Not only the earth, but even the whole solar system, according to Neweomb, “must have had a beginning within a certain number of years which we cannot yet calculate with certainty, but which cannot much exceed 20,000,000, and it must end.’’* The geologist demurs against these latter far too meager allotments of time for the wonderful, diversified, and surely vastly long history which he has patiently made out in his perusal of the volume of science disclosed by the rocks. He can apparently do very well with Lord Kelvin’s original esti- mate, but must respectfully dissent from the less liberal opinions noted. Somewhere in the assumed premises which yield to mathematicians these narrow limits of time there must be conditions which do not accord with the actual consti- tution of the sun and earth. It must be gratefully acknowl- edged, however, in the camp of the geologists, that we owe to these researches a beneficial check against the notion once prevalent that geologic time extends back practically without limit; and it is most becoming for us carefully to inquire how closely the apparently conflicting testimonies of geology and of physics may be brought into harmony by revision of each. Among all the means afforded by geology for direct esti- mates of the earth’s duration, doubtless the most reliable is through comparing the present measured rate of denudation of continental areas with the aggregate of the greatest determined thicknesses of the strata referable to the successive time divisions. Now the rates at which rivers are lowering the altitudes of their basins by the transportation of sediments to the sea vary from an average of one foot taken from the land surface of its hydrographic basin by the River Po in 730 years to one foot by the Danube in 6,800 years. As a mean for all the rivers of the world, Alfred Russel Wallace assumes that the erosion from all the land surface is one foot in 3 000 years. The sediments are laid down in the sea on an average * Popular Astronomy, pp. 5V5-519; Astronomy for Schools and Colleges, p. 501. 212 W. Upham—Estimates of Geologic Time. within 30 miles from the coast, and all the coast lines of the earth have a total measured length, according to Dr. James Croll and Mr. Wallace, of about 100,000 miles ; so that the deposition is almost wholly confined to an area of about 3,000,000 square miles. This area is one nineteenth as large as the earth’s total land area; hence it will receive sediment nineteen times as fast as the land is denuded, or at the rate of about nineteen feet of stratified beds in 3,000 years, which would give one foot in 158 years. With this Wallace com- pares the total maxima of all the sedimentary rocks of the series of geologic epochs, measured in whatever part of the earth they are found to have their greatest development. Prof. Samuel Haughton estimates their avoresate to be 177,200 feet, which multiplied by 158 gives approximately 28,000,000 years as the time required for the deposition of the rock strata in the various districts where they are thickest and have most fully escaped erosion and redeposition. Most readers, following this argument, would infer that it must give too large rather than too scanty an estimate of geologic duration ; but to many students of the earth’s strati- graphy it seems more probably deficient than excessive. All must confess that the argument rests upon many indeterminate premises, since the total extent of the land areas and the depths of the oceans have probably been increasing through the geologic areas, and the effects of tides have probably diminished. The imperfection of the geologic record, so impressively shown by Charles Darwin in respect to the sequence of plants and animals found fossil in the rocks, will also be appealed to as opposing the assumption that. the 177,200 feet, or 334 miles, of strata represent the whole, or indeed any more than a small fraction of the earth’s history. To myself, however, this last objection seems unfounded, since in many extensive and clearly conformable sections ob- served on a grand scale in crossing broad areas, there is seen to have been evidently continuous deposition during several or many successive geologic epochs, and by combining such sec- tions from different regions a record of sedimentation is made wellnigh complete from the earliest Paleozoic morning of life to its present high noon. But perhaps we may do better to change somewhat the premises of our computation, in view of the extensive regions where the rock strata remain yet to be thoroughly explored, and because of certain large land tracts having little rain and therefore no drainage into the sea. Let us assume that the total maxima of strata amount to 50 miles, and that the mean rate of the land denudation is only one foot in 6,000 years; and we then obtain a result three times greater than before, or about 84,000,000 years for the deposi- tion of the stratified rocks. W. Upham—Estimates of Geologic Time. 213 As a confirmation of the validity of his estimate of 28,000,- 000 years, Wallace cites the estimates differently obtained through the geologic time ratios of Lyell and Dana, in combi- nation with Dr. Croll’s astronomie theory of the causes of the Ice age, which attributes the accumulation of ice-sheets to stages of high eccentricity of the earth’s orbit. The Quater- nary Glacial period is assigned by this theory an extent of about 160,000 years, from 240,000 to 80,000 years ago. The next preceding epoch of great eccentricity was about 850,000 years ago, and to that time are referred large ice-borne blocks in Miocene strata of northern Italy. The union of this assump- tion with the time ratios for the Tertiary and earlier eras is explained as follows by Wallace in “ Island Life,” chapter x. Sir Charles Lyell, taking the amount of change in the species of mollusea as a guide, estimated the time elapsed since the commencement of the Miocene as one-third that of the whole Tertiary epoch, and the latter at one-fourth that of geological time since the Cambrian period. Professor Dana, on the other hand, estimates the Tertiary as only one fifteenth of the Mesozoic and Paleozoic com- bined. On the estimate above given [that the time since-a Miocene glacial epoch has been 850,000 years], founded on the dates of phases of high eccentricity, we shall arrive at about four million years for the Tertiary epoch, and sixteen mil- lion years for the time elapsed since the Cambrian, according to Lyell, or sixty millions according to Dana. The estimate arrived at from the rate of denudation and deposition (twenty-eight million years) is nearly midway between these, and it is, at all events, satisfactory that the various measures result in figures of the same order of magnitude, which is all one can expect on so difficult and exeeed- ingly speculative a subject. . . . The time thus arrived at is immensely Jess than the usual estimates of geologists, and is so far within the limits of the duration of the earth as calculated by Sir William Thomson as to allow for the develop- ment of the lower organisms an amount of time anterior to the Cambrian period several times greater than has elapsed between that period and the present day. Professor Haughton has estimated time ratios from two series of data. His results deduced from the maximum thick- ness of the strata for the three grand divisions of Archeean, Paleozoic, and subsequent time, expressed in percentages, are 34°3:42°5 :23°2; and from his computations as to the secuiar cooling of the earth, 33°0:41:0: 26:0. From his consideration of the present rates of denudation and the maximum thick- ness of the strata, he obtains “for the whole duration of geological time a minimum of two hundred millions of years.” In my opinion, this is a large rather than a small total esti- mate; but the length of Archean or pre-Cambrian time seems to me proportionately much greater than is here allowed. The ratios reached by Profs. J. D. Dana and Alexander Winchell, from the thicknesses of the rock strata, are closely harmonious, the durations of Paleozoic, Mesozoic, and Ceno- zoic time being to each other as 12:3:1. The Tertiary and Quaternary ages, the latter extending to the present day, are here united as the Cenozoic era. Professor Dana has further ventured a supposition that these three vast eras, from the Cambrian dawn until now, may comprise some 48,000,000 214 W. Upham—Estimates of Geologie Time. years, which would give for the Paleozoic era, 36,000,000 years; the Mesozoic, 9,000,000; and the Cenozoie, 3,000,000. He disclaims, however, any assumption that those figures are “even an approximate estimate of the real length of the inter- val, but only of relative lengths and especially to make apparent the fact that these intervals were very long.”* Prof. W. M. Davis, without speaking definitely of the lapse of time by years, endeavors to give some conception of what these and like estimates of geologic ratios really mean, threngh a translation of them into terms of a linear seale.t Starting with the representation of the Postglacial or Recent period, since the North American ice-sheet was melted away, as two inches, he estimates that the beginning of the Tertiary erosion of the Hudson River gorge through the Highlands would be expressed by a distance of ten feet ; that the Triassic reptilian tracks in the sandstone of the Connecticut valley would be probably 50 feet distant ; that the formation of the coal beds of Pennsylvania would be 80 or 100 feet back from the present time; and that the Middle Cambrian trilobites of Braintree, Mass., would be 200, 309, or 400 feet from us. Having such somewhat definite and agreeing ratios, derived froin various data by different investigators, can we secure the faetor by which they should be multiplied to yield the approxi- mate duration of geologic epochs, periods, and eras in years ? If on the seale used by Professor Davis we could substitute a certain time for the period since the departure of the ice sheet, we should thereby at once determine, albeit with some vague- ness and acknowledged latitude for probable error, how much time has passed since the Triassic tracks were made, the coal deposited, and the trilobites entombed in the Cambrian slates. Now just this latest and present division of the geologie record, following the Ice age, is the only one for which “geologists find sufficient data to permit direct measurements or estimates of its duration. “The glacial invasion from which New England and other northern countries have lately escaped,” remarks Davis, “ was prehistoric, and yet it should not be regarded as ancient.” In various localities we are able to measure the present rate of erosion of gorges below waterfalls, and the length of the postglacial gorge ‘divided by the rate of recession of the falls gives approximately the time since the Ice age. Such measnre- ments of the gorge and falls of St. Anthony by Prof. N. H. Winchell show the length of the Postglacial or Recent period to have been about 8,000 years ; and from the surveys of Niagara falls, Mr. G. K. Gilbert believes it to have been 7,000 years, more or less. From the rates of wave-cutting along the * Manual of Geology, p. 795. + Atlantic Monthly, July, 1891, p. 77. W. Upham—Estimates of Geologic Time. 215 sides of Lake Michigan and the consequent accumulation of sand around the south end of the lake, Dr. E. Andrews esti- mates that the land there became uncovered from its ice-sheet not more than 7,500 years ago. Prof. G. Frederick Wright obtains a similar result from the rate of filling of kettle-holes among the gravel knolls and ridges called kames and eskers, and likewise from the erosion of valleys by streams tributary to Lake Erie; and Prof. B. K. Emerson, from the rate of de- position of modified drift in the Connecticut valley at North- ampton, Mass., thinks that the time since the Glacial period cannot exceed 10, 000 years. An equally small estimate is also indicated by the studies of Gilbert and Russell for the time since the last great rise of the Quaternary lakes Bonneville and Lahontan, lying within the arid Great Basin of interior drainage, which are believed to have been contemporaneous with the great extension of icesheets upon the northern part of our continent. Prof. James Geikie maintains that the use of palseolithic implements had ceased, and that early man in Europe made neolithic (polished) implements, before the recession of the ice-sheet from Scotland, Denmark, and the Scandinavian peninsula ; and Prestwich suggests that the dawn of civiliza- tion in Eeypt, China, and India, may have been coeval with the glaciation of north western Europe. In Wales and York- shire the amount of denudation of limestone rocks on which bowlders lie has been regarded by Mr. D. Mackintosh as proof that a period of not more than 6,000 years has elapsed since the bowlders were left in their positions. The vertical extent of this denudation, averaging about six inches, is nearly the same with that observed in the southwest part of the Province of Quebec by Sir William Logan and Dr. Robert Bell, where veins of quartz marked with glacial strie stand out to various heights not exceeding one foot above the weathered surface of the enclosing limestone. Another indication that the final melting of the ice-sheet upou British America was separated by only a very short interval, geologically speaking, from the present time, is seen in the wonderfully perfect preservation of the glacial striation - and polishing on the surfaces of the more enduring rocks. Of their character in one noteworthy district, Dr. Bell writes as follows : “On Portland promontory on the east coast of Hud- son’s bay, in latitude 58°, and southward the high rocky hills are completely glaciated and bare. The strize are as fresh- looking as if the ice had left them only yesterday. When the sun bursts upon these hills after they have been wet by the rain, they glitter and shine like the tinned roofs of the city of Montreal. * Bulletin, Geol. Society of America, vol. i, p. 308. 216 W. Upham—Estimates of Geologic Time. From this wide range of concurrent but independent testi- monies, we may accept it as practically demonstrated that the ice-sheets disappeared from North America and Europe some 6,000 to 10,000 years ago. But having thus found the value of one term in our ratios of geologic time divisions, we may know them all approximately by its substitution. The two inches assumed to represent the postglacial portion of the Quaternary era may be called 8,000 years; then, according to the proportional estimates by Davis, the Triassic period was probably 2,400,000 years ago; the time since the Carbon- iferous period has been about four or five millions of years ; and since the middle of the Cambrian period, twice or perhaps four times as long. Continuing this series still farther back, the earliest Cambrian fossils may be 20 or 25 millions of years old, and the beginning of life on our earth was not improbably twice as long ago. Seeking to substitute our measure of postglacial time in Professor Dana’s ratios, we are met by the difticulty of ascer- taining first its proportion to the preceding Glacial period, and then the ratio which these two together bear to the Tertiary era. It would fill a very large volume to rehearse all the diverse opinions current among glacialists concerning the his- tory of the Ice age, its wonderful climatic vicissitudes, and the upward and downward movements of the lands which are covered with the glacial drift. Many eminent glacialists, as James Geikie, Wahnschaffe, Penck, De Geer, Chamberlin, Salisbury, Shaler, McGee, and others, believe that the Ice age was complex, having two, three, or more, epochs of glaciation, divided by long interglacial epochs of mild and temperate climate when the ice-sheets were entirely or mainly melted away. Professor Geikie, in a recent very able paper,t claims five distinct glacial epochs, as indicated by fossiliferous beds lying between deposits of till, and by other evidences of great climatic changes. In this country Mr. McGee recognizes at least three glacial epochs. The astronomic theory of Croll attributes the accumulation of ice-sheets to recurrent cycles which bring the earth alternately into aphelion and perihelion each 21,000 years during the periods of maximum eccentricity of the earth’s orbit. Its last period of this kind, as before stated, was from about 240,000 to 80,000 years ago, allowing room for seven or eight such cycles and alternations of glacial and interglacial conditions. The supposed evidence of inter- glacial epochs therefore gave to this theory a wide credence ; but the recent determinations of the geologic brevity of the time since the ice-sheets disappeared from North America * “On the Glacial Succession in Europe,” Trans. Royal Society of Edinburgh, 1892, vol. xxxvii, pp. 127-149, with map. W. Upham— Estimates of Geologie Time. 217 and Europe make it clear in the opinions of some of the geologists who believe in the duality or plurality of Quater- nary glacial epochs, that not astronomic but geographic causes produced the Ice age. Glacialists who reject Croll’s ingenious and brilliant theory mostly appeal to great preglacial altitude of the land as the chief cause of the ice accumulation, citing as proof of such altitude the fiords and submarine valleys which on the shores of Scandinavia and the Atlantic, Arctic, and Pacific coasts of North America, descend from 1,000 to 3,000 and even 4,000 feet below the sea level, testifying of former uplifts of these continental areas so much above their present heights. But beneath the enormous weight of their ice-sheets these lands sank, so that when the ice attained its maximum area and thickness and during its departure the areas on which it lay were depressed somewhat lower than now, and have since been re-elevated. This view to account for the observed records of the Ice age is held by Dana, LeConte, Wright, Jamieson, and others, including the present writer. It is believed to be consistent either with the doctrine of two or more glacial epochs during the Quaternary era, or with the reference of all the glacial drift to a single glacial epoch, which is thought by Wright, Prestwich, Lamplugh, Falsan, Holst, and others, to be more probable. To myself, though formerly accepting two glacial epochs, with a long warm inter- val between them, the essential continuity of the Ice age seems now the better provisional hypothesis, to be held with candor for weighing evidence on either side. The arguments sup- porting this opinion are well stated by Professor Wright.* If there was only one epoch of glaciation, with moderate tempo- rary retreats and re-advances of the ice-border, sufficient to allow stratified beds with the remains of animals and plants to be intercalated between accumulations of till, the duration of the Ice age may only have comprised a few tens of thousands of years. On this point Professor Prestwich has well written as follows: For the reasons before given I think it possible that the Glacial epoch—that is to say, the epoch of extreme cold—may not have lasted longer than from 15,000 to 25,000 years, and I would for the same reasons limit the time of ...... the melting away of the ice-sheet to from 8,000 to 10,000 years or less.+ - From these and foregoing estimates which seem to me acceptable, we have the probable length of Glacial and Post- glacial time together 80,000 or 40,000 years, more or less ; but an equal or considerably longer preceding time, while the *The Ice Age in North America, 1889, chapters xix and xx. Man and the Glacial Period, 1892, pp. 117-120 and chapters ix and x. ‘t Unity of the Glacial Epoch,” in this Journal, Noy., 1892. + Geology, vol. ii, p. 534, 218 W. Upham—Estimates of Geologic Time. areas that became covered by ice were being uplifted to high altitudes, may perhaps with good reason be also included in the Quaternary era, which then would comprise some 100,000 years. The best means for learning the relative lengths of Tertiary and Quaternary time I think to be found in the changes of faunas and floras since the beginning of the Ter- tiary era, using especially the marine molluscan faunas as most valuable for this comparison. Scarcely any species of marine mollusks have become extinct or undergone important changes during the Glacial and Recent periods, but since the Eocene dawn of the Tertiary nearly all of these species have come into existence. Judged upon this basis, the Tertiary era seems probably fifty or a hundred times longer than the Ice age and subsequent time; in other words, it may well have lasted two millions or even four millions of years. Taking the mean of these numbers, or three million years, for Cenozoie time, or the Tertiary and Quaternary ages together, we have precisely the value of Professor Dana’s ratios which he himself assumes for conjectural illustration, namely, 48,000,00( years since the Cambrian period began. But the diversified types of animal life in the earliest Cambrian faunas surely imply a long ante- cedent time for their development, on the assumption that the Creator worked before then as during the subsequent ages in the evolution of all living creatures. According to these ratios, therefore, the time needed for the deposition of the earth’s stratified rocks and the unfolding of its plant and animal life must be about a hundred millions of years. Reviewing the several results of our different geologic esti- mates and ratios supplied by Lyell, Dana, Wallace and Davis, we are much impressed and convinced of their approximate truth by their somewhat good agreement among themselves, which seems as close as the nature of the problem would lead us to expect, and by their all coming within the limit of 100,000,000 years which Sir William Thomson estimated on physical grounds. This limit of probable geologic duration seems therefore fully worthy to take the place of the once almost unlimited assumptions of geologists and writers on the evolution of life, that the time at their disposal has been prae- tically infinite. No other more important conclusion in the natural sciences, directly and indirectly modifying our coneep- tions in a thousand ways, has been reached during this century. The error by which Mr. McGee, in the estimate stated in the early part of this article, wanders so far astray, consists in his relying largely on Dr. Croll’s theory for the cause of the . Glacial period, whereby he concludes that this period was of great length and that the ice-sheets were due to astronomie conditions while the land through the Ice age had somewhat W. Upham: Estimates of Geologie Time. 219 approximately its present height, with only moderate uplifts and depressions. Drawing his ratios of Postglacial and Glacial time, and of the preceding early Quaternary or late Tertiary epoch to which the Lafayette formation belongs, from the amounts of stream erosion, he has supposed the conditions then similar to those of the present time, so that the relative durations of these epochs may be estimated from their excava- tions of valleys by water courses. But it seems preferable, as before noted, to refer the Ice age to great elevation of the land, whereby the erosion of streams would be caused to pro- ceed very much more rapidly than if the country were as low as now. With an altitude of our Atlantic coastal plain and whole continental area westward 3,000 feet higher than now, the valley-cutting may have gone forward twenty ora hun- dred timés faster than to- day, or even near the coast a thousand times faster than now. The factor with which Mr. McGee starts on the multiplication of the earlier ratios to change them to years is evidently far too large, and it gives therefore for all the geologic eras and for the earth’s total age too vast figures probably by twentyfold to a hundredfold. Anthropologists, not less than geologists, have a lively interest in the estimates and measurements of the length of the Glacial and Recent periods, for the earliest reliable testi- mony of man’s existence comes to us from the Ice age, both in North America and Europe. Confining our attention to the observations which prove that men were living on our continent as contemporaries of its northern ice-sheet, we have many independent and widely separated localities where traces of man’s presence during the Glacial period have been found. Under the beach ridge of gravel and sand on the south side of Lake Iroquois, the glacial representative of Lake Ontario, charred sticks, with ashes and stones laid to form a rude hearth, were discovered about 18 feet below the surface in digging a well in Gaines township, Orleans county, N. Y. Lake Iroquois was dammed on the northeast by the receding continental ice-sheet and outflowed by way of the Mohawk and Hudson. The hearth and fire were made, according to Mr. G. K. Gilbert, “not long after the establishment of the Mohawk outlet and during its continuance.” To a much earlier stage of the glacial recession we must refer the exten- sive gravel deposits of the Delaware River in the vicinity of irenton,, Ne J.,,in which Dr. C. C. Abbott, Prof. Kh. W. Putnam, and others have found many paleeolithic implements and chipped fragments of argillite.* Somewhat farther south, * Since this paper was written, two articles by Mr. W. H. Holmes in Science (Noy. 25, 1892, and Jan. 20, 1893) lead me to uncertainty whether the traces of man’s existence in this country during the Glacial period are referable, as has been hitherto supposed, to a technically palzeolithic stage of culture. They seem Amu. Jour. Sci.—TuHinp Series, Von. XLV, No. 267.—Marcu, 1893. 16 220 W. Upham—Estimates of Geologie Tvme. in Delaware, Mr. Hilborne T. Cresson has found similar paleoliths in glacial gravel belonging to a still earlier part of the Ice age, probably deposited during the maximum exten- sion of the ice-sheet. Other localities where paleoliths have been discovered in glacial gravel and sand beds, formed during the departure of the ice, are Newcomerstown, on the Tus- carawas river, in eastern Ohio; on the Little Miami river at Loveland and Madisonville, in southwestern Ohio; on the East fork of the White river at Medora, in southern Indiana; and on the upper Mississippi at Little Falls, in central Minne- sota. Again, in one of the beach ridges of the glacial Lake Agassiz, held in the basin of the Red river of the North and of Lake Winnipeg by the barrier of the waning ice-sheet, Mr. J. B. Tyrrell has found chipped fragments of quartzite, evi- dently of human workmanship, contemporaneous with the rounded gravel and wave-worn sand of the beach. West of the Rocky Mountains, also, an obsidian spear-head was dis- covered by McGee in the sediment of the Quaternary Lake Lahontan ; and stone mortars, pestles, and even human bones, including the famous Calaveras skull, have been obtained by Whitney, King, Becker, Wright, and others, from the gold- bearing gravels under the lava of Table mountain, California. Though these last are south of the continental drift sheet, they seem referable on sufficient geologic evidences, to the Pleisto- cene or Glacial period. At one time the Californian discoveries were believed by some to prove man’s presence there during the Pliocene period, far longer ago than the Ice age; but no indisputable proof, nor even apparently reliable evidence, for so great antiquity of man has been brought to light in any part of the world. Homo sapiens, as Professor LeConte stated in discus- sions of this subject at the meeting of the American Associa- tion last August in Rochester, N. Y., must be regarded, in the present stage of our knowledge, as restricted to the Quater- nary era, although his anthropoid ancestors may have begun as far back as in Pliocene or Miocene time their ascent toward man’s present intellectual and spiritual eminence. to me to prove indubitably that men were living here contemporaneous with the ice-sheet, but these men may have possessed the skill to make both rough and polished implements of stone, corresponding with the Neolithic age in Kurope. The wide geographic range of the native American race, its differentiation into many divergent branches, and the very remarkable advances of some of them toward civilization before the discovery by Columbus, as in Mexico, Central America, and Peru, indicate that the original peopling of the continent, which was apparently by migration from northeastern Asia, took place before the culmi- nation of the Glacial period, probably during an immediately preceding time of general elevation of northern countries so that land extended across the present areas of Bering Strait and Sea. It may well be true, but probably cannot be proved, that even at that early time the people taking possession of North and South America had attained the stage of culture characterized by the partial use- of polished stone implements. A. Winslow—Cambrian in Missouri. 291 Art. XX VII.—WNotes on the Cambrian in Missouri and the Classification of the Ozark Series ; by ARTHUR WINSLOW. Introductory Remarks.—The Magnesian or Ozark series of rocks in Missouri covers nearly the entire southeastern quarter of the State. The members consist chiefly of dolomitic lime- stones and sandstones. They were assigned by the first Geo- logical Survey of the State to the Lower Silurian and Calcifer- ous age and were classified as follows, from the top downwards:* First Magnesian Limestone. Saccharoidal Sandstone. Second Magnesian Limestone. Second Sandstone. Third Magnesian Limestone. Third Sandstone. Fourth Magnesian Limestone. Fourth Sandstone. This assignment and classification were followed, with slight modifications, by Shumard, Meek, Broadhead and others in later works, though, in the first report*cited,+ the discovery of a trilobite is noted in the Third Magnesian limestone which was considered identical with one in the Potsdam sandstone of New York, and in later reports and papers Broadhead refers to the lower members of the series as of probable Potsdam age.t Walcott, in recent writings, reasoning largely from the published results above referred to, has included the lower members of the Ozark series in the Cambrian§ and expresses this conclusion in the following words: | “The Cambrian rocks in Missouri occur in the southwestern4 portion of the State, about the Ozark Uplift. As far as known they are of Upper Cambrian age and consist of a sandstone that occurs beneath the third magnesian limestone, or Calciferous, and the fourth magnesian limestone of the Missouri survey, beneath which, according to Prof. G. C. Broadhead, there are other arenace- ous and calcareous beds.” According to this the last three numbers of the table given above would belong to the Cam- brian. Recent work of the present Geological Survey of Missouri has shown that a re-classification of the members of the Mag- * Swallow. 2nd Annual Report 1854, Part I, pp. 115 to 130. 4 Ibid., p. 124. { Report Missouri Geological Survey 1873-74, pp. 352, 257, 358. § The North American Continent in Cambrian Time, and Bulletin No. 81, U.S. Geological Survey, Correlation Papers—Cambrian. | Bulletin 81, p. 339. J Southeastern probably meant. 999 A. Winslow—Cambrian in Missouri. nesian series is necessary,* and it is further tending to the con- elusion that rocks placed higher in the series than the Third sandstone are of Cambrian age. As bearing upon these ques- tions the results of studies recently made by the writer in Madison, St. Francois and Ste. Genevieve counties are here presented. Fig. 1.—Outline map of St. Genevieve, St. Francois and Madison Counties. Previous Results in St. Genevieve County.—St. Genevieve county is in the eastern portion of the State, about 40 miles south of St. Louis. As is shown in the adjoining sketch it is bordered by the Mississippi river on the east, by St. Francois * Vol. ii, Report Missouri Geological Survey, 1892; Iron Ores, chap. v. teed ¥~ A. Winslow—Cambrian im Missouri. 923 county on the west and corners with Madison county on the southwest. A description of the geology of this county by B. F. Shumard was published in 1871,* from results of work done during earlier years. According to this report the country lies on the eastern flank of the Ozark uplift and, proceeding from the river westwards, the upturned edges of the eastward dipping strata of Carboniferous, Devonian, Upper and Lower Silurian ages are successively encountered. It is with the last of these alone that we are concerned here. The report de- scribes among the rocks of this period,t the First magnesian limestone, the Saccharoidal sandstone, the Second magnesian limestone, the Second magnesian sandstone and the Third magnesian limestone, as they are found in this county, one under the other, dipping gently to the east. The Second magnesian limestone, in which we are specially interested, is statel to occupy a large area chiefly in the central and northwestern portions of the county, and to ex- tend across the eastern half of the county in a belt from one to three miles wide. The Second sandstones, in which we are also interested, is described as constituting the surface rock over ‘a larger portion of the country than any other formation and is present in greater vertical development. It is particularly well shown over the high central portion of the county. It is described as varying in lithological character, but usually ap- pears in thin beds of white, yellow, or reddish colors and made up of moderately fine siliceous grains ; sometimes, however, it is coarse-grained to the extent of being a grit-stone or con- glomerate, containing large pebbles of milky translucent quartz. The thickness is stated to be 150 ft. The Third magnesian limestone is described as occurring in the western and southern portions of the county, with the “usual lithological characteristics.” Previous Lesults in Madison County.—The geology of Madison county was described by Broadhead in 1873.{ Accord- ing to this report the sedimentary strata fill the valleys between mountains and hills of Archean rocks. The general section of these strata given is as follows, from the top downwards. Sandstone. Chert beds and magnesian limestone. Magnesian limestone. 3. Grit-stone with some magnesian limestone. 2. Marble beds. 1, Sandstone. bat SD * Report Missouri Geological Survey, 1871, pp. 289 to 303. + Opus cit., pp. 298 and 299. t¢ Report Mo. Geological Survey, 1873 to ’74, pp. 342 to 379. 224 A. Winslow—Cambrian in Missouri. The members of this section numbered 1, 2, and 3 and part of 4 are placed in the Potsdam ; the upper one hundred feet or more of 4 are described as belonging to the Third magnesian limestone; numbers 5 and 6 are placed in the Calciferous and 6 is thought to be probably the ‘Third sandstone.” The lowest sandstone (1) is described as occurring in the northern part of the county, in between the granite hills; it is generally fine grained and of white or buff color, or may be a coarse, brown or red conglomerate. Thicknesses of from 40 to 90 feet are exposed in places. The sandstone found about Mine La Motte is included in this description. The marble beds (2) are found only at a few localities in the central and southwestern portions of the county. The grit- stones are similarly exposed only at a few points. The mag- nesian limestones (4) are stated to be of wide distribution ; the lower beds are placed in the Potsdam and are separated from the upper beds, of 160 feet or more, which are grouped under the head of the Third magnesian limestone, though the reasons for this separation are not very clear. The chert and sand- stones (5 and 6) occupy the hill tops in scattered patches. No explanation is given of the stratigraphic structure of county and the reasons for differentiating the marble and grit- stone beds (2 and 38) and for placing them at the places desig- nated in the section are not plain. Previous fesults in St. Francois County.—No_ report especially describing St. Francois county has been published ; but the sedimentary rocks there are in direct continuation of those of Madison county and the prevalent limestone has generally been considered to belong, in great part at least, to the Third magnesian. According to our understanding, then, the interpretation of the stratigraphy and structure of this region to be drawn from these reports would be as is expressed in the following section, along the line A, B, drawn in the sketch map on p. 222. ron Mountain FARMINQTON ST Francois @ St.Genevieve Go} AMiasibsippe River ny ARCHEAW $e St. Genevieve « a “ ° AGNESIAN LIMESTONE” SECOND SANDSTONE 2D. MAGNES. L.S, “sacen® UPPEB SILURIAN | DEVONIAN AND CARBONIFEROUS KG ca od ar! Fig. 2.—A generalized section across St. Francois and St. Genevieve counties, expressing the results of early work. Results of the present Geological Survey.—During the past few years the present Geological Survey has prosecuted field work during part of each field season in this section of the A. Winslow—Cambrian in Missouri. 225 State. In this period the writer has carefully examined numerous outcrops and exposures and has, further, had the benefit of the results of a large amount of diamond drilling and shafting which have been done here, notably in the vicinity of Bonne Terre, Flat River, Farmington, Doe Run, Iron Mountain, Mine La Motte and Fredericktown. ‘The results of this work all go to show that in St. Francois and in the north- ern part of Madison counties the sedimentary rocks between and beyond the granite and porphyry hills may be divided into the following three parts from the top downwards. Observed thicknesses. ‘ Feet. 1, Limestone, magnesian, crystalline; immediately under- lies most of the valleys and constitutes the bulk of the non-Archean hills. In thin and massive beds; includes some shale, espe- cially in the lower parts ; arenaceous layers encountered at places, but are of subordi- nate importance and not persistent. This is the lead-bearing horizon of southeastern Miss Oui ose ident gies calle toro OO 2. Sandstone, of white, gray and reddish colors ; gene- "rally composed of pure quartz grains “with secondary enlargements liberally devel- oped ; sometimes thinly bedded, even shaly, elsewhere massive, but generally friable and. dificult to dmll through 3222 0 yas 1 to 100 3. Conglomerate, composed of granite or porphyry bowl- ders with a limestone, grit or clayey matrix, 1 to 50 Granite or porphyry floor. This section is, of course, not represented in full every- where. The best succession is perhaps found in the center or the broader valleys, between the Archean hills. As one approaches the sides of the valleys any or all of the beds may taper out. The detrital conglomerate would, naturally, not be found resting against a steep granite wall, but the bowl- ders would have slid or rolled to lower levels; the lime- stone, being often at higher level than the sandstone, may extend beyond the latter up a concealed hill slope of gran- ite or porphyry and, thus, be often directly in contact with either of these latter rocks, or with the conglomerate derived from them. On the other hand, a thickening of the sandstone towards its source, an inclination of the floor or a slight dip, aided by erosion, may bring the sandstone to view at a higher elevation than the geologically higher limestone. This is the case in the vicinity of Doe Run; about three miles southeast of that place the sandstone, which underlies the limestone con- . 296 A. Winslow—Cambrian in Missouri. taining the lead ore at the Doe Run mine, rises to the surface and is exposed in the bluffs of the hills to a thickness of 70 ft. or more. This bottom sandstone is encountered in the vicinity of Flat River at depths of about 400 ft. Eastward from that place, however, numerous drill holes put down in late years show that the sandstone rises higher and higher and, about two miles east of Farmington, it is exposed at the surface, on Wolf creek. Thence, in the same direction, towards St. Genevieve, this rock continues to occupy the surface to about the middle of the county. Limestone then comes in again with an eastward dip and is, in turn, succeeded by the overlying Saccharoidal sandstone described by Shumard. According to our views, then, the section along the line A—B, is as follows: Farniing fon St Francois Co St, Genevieve Co, Rigtigenent ve fe. 3 Re » 2 q 2 Wississippi River LIMESTONE. SANDSTONE, LIMESTONE, Saccn” UPPER SILURIAN age re ) 21.27 27°8 2°6 157 —Al: G 8 Cater Sesseseese 21-46 1929) 3°4 012 +53° G @ PERARIL ecole noee 21°65 80°6 2°4 ‘023 1 010 V-S Recasi eaters = 22°61 CH 35 073 — 6 G pf JCSRR Eee ve 22 64 60°3 3:0 033 — 9 G&s (6) ISERNSEe eee ee 22°98 62°5 255 219 + 4:1 Vv @, IPERS so coeee bae 22599 755 2°5 063 + 0°8 V-S Art. XXXIL—On the Double Halides of Tellurium with Potassium, Rubidium and Cesium ; by H. L. WHEELER. THE existence of double halides of tellurium with potas- sium, sodium and ammonium was first indicated by Berzelius.* He described the methods by which he obtained them, but gave no analyses of the compounds. Later, Rammelsbergt investigated the double chlorides of tellurium with potassium and ammonium, with the object of determining their compo- sition. He arrived at the formule 8KCI. 38TeCl, and 8NH,Cl. * Poge. Ann., xxxii, 577. + Berlin Monats. Ber., 1875, 379. 268 H. L. Wheeler—Double Halides of Tellurium 3TeCl,. It will be shown beyond that the formula of the potassium compound at least must have been obtained from analyses of impure products. Von Hauer* analyzed the double bromide of tellurium and potassium, and concluded that the salt had the composition represented by the formula 2K Br.TeBr,.8H,O. I have reinvestigated this salt and found it to contain two molecules of water and not three. Probably Von Hauer analyzed the salt without previously having dried it sufficiently or without having taken precan- tions to remove included water which the crystals always con- tain. He dehydrated this salt and used it in his work on the atomic weight of tellurium. More recently Wills+ determined the atomic weight of tellurium by means of the same salt. He does not give any analyses of the hydrous compound, but states that the salt contains water and gives directions for dehydrating it. Ram- | melsberg in his “ “Handbuch der krystallographisch- physi- kalischen Chemie” (p. 289) quotes the formula of the dehy- drated compound from Wills’ work and assigns to this Baker’s{ measurements, which do not belong to it, but to the hydrated compound with the three supposed molecules of water of crystallization. The present investigation has shown that the anhydrous salt is isometric, the hydrous one being orthorhombie. Ramsay§$ says that “By mixing aqueous solutions of the constituent halides, tellurium halides combine thus: TeCl, 2KCl, TeBr,2K Br, Tel,2Ki. These compounds form reddish crystals. Few attempts have been made to prepare double halides.” Although a thorough search of the literature on this subject has been made, in connection with the present work, no analyses of the double chloride or iodide could be found. LBerzelius’s work as regards their preparation and Rammelsberg’s attempt to determine the formula of the chloride comprise all the work that has been done on these two salts. It must be concluded that the formule given by Ramsay were deduced by analogy with the double bromide, especially since his statements in regard to color, method of preparation and composition only apply, in all respects, to the double bromide. It will be seen from the above summary that very little satisfactory work has been done on this class of compounds, and, therefore, the present investigation has been undertaken with the view of making a thorough study of the double * Journ. prakt Chem., Ixxiii, 98. + Jour. Chem. Soc., xxxv, 711. t Jour. Chem. Soc, xxxv, 711. § System of Inorganic Chemistry, edition of 1891, p. 168. with Potassium, Rubidium and Cesium. 269 halides of tellurium with potassium, rubidium and cesium. As a result the following compounds have been prepared : AKO .AUXCN 2RbCl . TeCl, 2CsCl . TeCl, 2KBr . TeBr, 2RbBr. TeBr, 2CsBr. Tebr, 2K Br . TeBr,. 2H,O 2RbI. Tel, 2Csl. Tel, 2KI . 2Tel,.2H,O It is to be noticed that all of these compounds conform to the usual type of double halides of tetravalent metals in con- taining the alkali metal and tellurium in the ratio of two atoms of the former to one of the latter, and no indications of the formation of salts of a different type were observed. The anhydrous double halides of tellurium crystallize in the iso- metric system, with an octahedral habit, and it is an interest- ing fact that this form seems to be characteristic for anhydrous double halides of this type. The cesium and rubidium salts are new compounds, as well as the crystallized, anhydrous, double potassium bromide. New formulae have been assigned to the hydrous potassium double bromide and to the double iodide of potassium. A considerable difference is shown in the affinity of the double halides of tellurium and potassium for water of crystallization. The double chloride is anhydrous and no hydrous form of it was observed, the double bromide was prepared in both the hydrous and the anhydrous forms, while the iodide was obtained only with water of crystalliza- tion. This water was more firmly held than in the case of the hydrous bromide, as was shown by the fact that it formed from hot solutions and did not as readily eftloresce. The methods used in the preparation of pure material for this work, and which deserve to be mentioned on account of giving satisfactory results, are given below. The tellurium was obtained by purifying the commercial product by precipi- tation with sulphurous acid, according to the method of Divers and Shimosé.* The halides of tellurium were prepared from this material in the usual way. Cesium chloride was obtained in a pure state by the method of Godeffroy.t The bromides and iodides were obtained in the usual manner from the carbonate, the latter having been prepared from the pure chloride by converting into nitrate, then into oxalate and igniting the latter, as suggested by J. L. Smith,t for the conversion of potassium chloride into carbo- nate. The rubidium was purified by Allen’s§$ acid tartrate method. In the case of the potassium salts, Kahlbaum’s pure material was used. * Jour. Chem. Soc., xlvii, 439. + Ber d. chem. Ges., vii, 375. ¢ This Journal, II, xvi, $73. § Ibid., I], xxxiv, 367. 270 H. L. Wheeler—Double Halides of Tellurium The methods by which the double halides were obtained will be given with the description of the salts. Method of Analysis. The anhydrous salts were removed from the mother liquor, and, after pressing on filter paper, were dried in the air. The hydrous compounds were rapidly crushed on smooth filter paper, and, as soon as it was certain that no included water was retained by the fragments, they were placed in weighing tubes. Portions of about one-half a gram were taken for analysis. In order to determine the halogens, silver sulphate was added to the solution of the weighed sample in water containing a little sulphuric acid. The silver halide was washed, ignited and weighed in the usual manner. After the removal of the excess of silver by means of hydrochlorice acid, tellurium was removed with hydrogen sulphide. This separa- tion of tellurium, best in warm solution, has been found to be complete in a few minutes and in a condition that admits of filtration without inconvenience. ‘The sulphide of tellurium, filtered on asbestus in a Gooch erucible, was washed with water containing a little hydrogen sulphide, then treated with a solution of bromine in dilute hydrochlorie acid, which readily dissolves the moist sulphide. An excess of nitric acid was then added to this solution and the whole evaporated on the water bath, the resulting tellurous acid, being transferred to platinum, was ignited and weighed as TeO,. The alkali metals were determined by evaporating the filtrate from the tellurium sulphide to dryness, with an excess of sulphuric acid. The residues were then converted into normal sulphate by ignition in a stream of ammonia, as suggested by Kriss for potassium sulphate. In the case of the hydrous salts, water was determined by heating them in an air bath to constant weight; the residues were analyzed and found to correspond in composition to the anhydrous salts. The atomic weights used in the calculation of the results were the following: Te, 125; K, 39:1; Rb, 85:5; Cs, 133; Cl, 35:5; Br, 80+ I 1am Solubility. The salts are all decomposed by water. The double bro- mides, however, show an interesting difference in their deport- ment with this reagent. Potassium tellurium bromide dis- solves in a small amount of water, but, if an excess of water is added, tellurous acid separates, as has been observed by Wills.* Rubidium tellurium bromide also dissolves in a *loe. cit. with Potassium, Rubidium and Casiwin. Dil little hot water completely, the difference being shown on cooling, when a considerable portion of the tellurium separates as tellurous acid. While in the case of the czesium salt both hot and cold water, in large and small amounts, fail to dissolve the salt, the result being immediate decomposition. Only a small part of the tellurium in this case goes into solution. Most of these double salts can be conveniently recrystallized from dilute solutions of the corresponding acid. The excep- ‘tions are potassium-tellurium chloride, which is decomposed by this treatment, and cesium-tellurium iodide, which is practi- cally insoluble in hydriodic acid. The fact, first noticed by Godeffroy,* that double halides, containing the metals potas- sium, rubidium and vesium, generally decrease in solubility from potassium to cesium, which has frequently been noticed in this laboratory, is again wellillustrated by these compounds. For the determination of the solubility of these salts in acids, they were finely powdered, and saturated solutions were then prepared by digesting a mixture of the acid and an excess of the salt for about a week, at ordinary temperature. This was done in a closed flask. Weighed portions of these solutions were evaporated to dryness and the residues dried at 100° and weighed. These solubilities were all taken at 22°, and the results are the average of two or more closely agreeing deter- minations. 100 parts HCl 100 parts HCl Sp. gr. 1:2 dissolve Sp. gr. 1:05 dissolve vib Cle eC] eae se 0°34 parts. 13°09 parts. 2OSC a MeCly Sse 2 Ode = Oe7a 100 parts HBr 100 parts HBr Sp. gr. 1°49 dissolve Sp. gr. 1:08 dissolve Di Bits ANS Bis ages 6°57 parts. 62°90 parts. ay ee Ane ieee ees Orbs Bist 1S 2CsBr 2 Mebr eae 105020) Owl Seeiee The double tellurium chlorides, described in this article, are more soluble than the bromides, and the bromides more soluble than the iodides. The solubility of these compounds in strong alcohol shows the same gradation as their solubility in acids, the czesium salts being practically insoluble in this men- struum, while the rubidium salts dissolve to a trifling but clearly perceptible extent, and the potassium salts dissolve con- siderably or are decomposed with separation of the potassium halide, or both solution and decomposition take place, accord- ing to the salt experimented with. * Ber. d. Chem. Ges., viii, 9. 2 H. L. Wheeler—Double Halides of Tellurium The Chlorides. The erystals of the three chlorides have a pale yellow color, resembling that of the well known ammonium phospho-mo- lybdate precipitate, the shade becoming somewhat lighter from the czesium to the potassium salts. Cesium tellurichloride, 20sCt. TeCl,,—In the preparation of this compound, and also in the preparation of the rubidium and potassium double chlorides, the tellurium tetrachloride is most conveniently made by converting tellurium into tellurous oxide by means of aqua regia, evaporating to dryness to expel nitric acid and then dissolving the residue in hot hydrochloric acid. An aqueous solution of cxsium chloride, added to this, produces a precipitate, even in quite dilute solutions. There must be an excess of hydrochloric acid present to prevent the separation of tellurous acid. On boiling and adding more water, if necessary, this precipitate dissolves. The solution, left to cool, deposits small brilliantly lustrous octahedrons. It is a general fact with these double halides, that an excess of one or the other of the constituents does not affect their com- position. This is shown in this particular case by the fact that it can be recrystallized from strong solutions of tellurium or of cxsium chlorides. Analysis gave: Calculated. GO sasp hese sae 43°44 43°90 44°63 44°04 A Dee Socata 20°65 Bess 21°41 20°69 Client ee RIO LOS 30°14 raters 35°27 This compound is perfectly stable in the air. It does not melt below the boiling point of sulphuric acid. It can be precipitated from its solution in dilute hydrochloric acid by the addition of concentrated hydrochloric acid. A portion of the salt, finely pulverized, was treated with water at ordinary temperature. This produced a voluminous white precipitate, which was washed with cold water and dried in the air. Analysis gave: Calculated for H.TeOs. A Leslee oa Lae 71°45 71°43 EL Ose Le EM tole 10°29 OR eB ee TO 18°28 Ose ie een 2°49 (Ofna oY ses 0°80 The oxygen which was not given off in the form of water on heating the substance was calculated by difference.. From the above analysis the conclusion may be drawn, that the pre- cipitate produced by the action of water on this salt is essen- tially tellurous acid, a small amount of oxychloride of tellurium with Potassium, Rubidium and Coesium. 273 being present. Hot water dissolves some of this tellurous acid, and, on cooling slowly, the anhydride separates in the characteristic form of colorless octahedrons. Rubidium tellurichloride, 2Rb01. TeCl,—The preparation of this salt was in every way analogous to that of the czesium tellurium chloride. However, since this salt is far more solu- ble than the corresponding cesium compound, no precipitate was obtained in dilute solutions. The mixture of the hydro- ehloric acid solution of the constituents was concentrated by evaporation, and, when cooled, crystals separated. These were in the form of octahedrons, somewhat larger than the cesium salt. Calculated for Analysis gaye: 2RbC1. TeCls. | Roy eee ees oe ae 33°50 33°83 33°59 ARG, CSE ee SE wees 24°34 Drepate 24°56 Chae eer se pete es 41°85 This salt remains permanent in the air. From the dilute hydrochlorie¢ acid solution, concentrated hydrochloric precipi- tates it unaltered. Water decomposes it, evidently in the same way as the ceesium salt. Potassium tellurichloride, 2K Cl. TeCl,—To prepare this salt in a pure state an excess of tellurium chloride is necessary. The analyzed material was obtained by spontaneous evapora- tion of the constituents in a solution of dilute hydrochloric acid, twice as much tellurium chloride being present as re- quired by the formula. Under these conditions it was found to separate in the form of light yellow octahedrons, which, under the microscope, were shown to be free from potassium chloride. Analysis gave: Calculated for Ratio. 2KCl1. TeCl,. Vik 62 en Wes “44 18°79 MOTEL Is AES 30°29 "24 30°03 Ohare ae 49°47, 1°39 61°18 97°13 The salt, therefore, has the formula 2KCl.TeCl,. The crystals deliquesce somewhat in moist air and the analyzed material retained a small amount of water, as is shown by the deficiency in the above analysis. It is not probable that the salt contains water of crystallization, for the crystalline form and optical properties show that it is isomorphous with the anhydrous salts. ‘This salt is the most unstable as well as the most soluble of the anhydrous double halides described in this article. It is readily dissolved by dilute hydrochloric acid. 204 H.. L. Wheeler Double Halides of Tellurium Strong hydrochloric acid separates potassium chloride. It therefore cannot be precipitated from its solutions by the addi- tion of strong hydrochloric acid, as in the case of the other chlorides. Alcohol also separates potassium chloride. Water apparently effects the same decomposition as in the ease of the cesium and rubidium chlorides. The tendency of potassium chloride to separate along with the salt explains why Rammels- berg’s analysis came high in regard to the potassium chloride. His results corresponded to a mixture of two molecules of KCl and three molecules of 2KO].TeCl, Experiments with the calculated quantity of the constituents invariably resulted in the separation of potassium chloride or potassium chloride mixed with the yellow 2KCl.TeCl, Experiments with the method given by Ramsay* for the preparation of this salt, by mixing aqueous solutions of the constituents, re- sulted in the decomposition of the tellurium chloride, and the resulting white precipitate failed to dissolve until con- siderable hydrochloric acid was added. Attempts to prepare the compound by concentrating the mixture of the con- stituents by the aid of heat invariably resulted in failure. In certain cases, on cooling such solutions, a mass of colorless slender prisms was obtained, which will be described in a future article. The Double Bromides. The crystals of the anhydrous bromides have a brilliant red color resembling that of the mineral crocoite. The powders of the salts have a color that is similar to that of a mixture of equal parts potassium bichromate and red lead. The powder of the hydrous bromide has the color of mercuric oxide, but, by loss of water, this soon changes to that of the anhydrous salt. ; Cesium telluribromide, 2Cs Br . Te Br,.—This double halide can easily be prepared by mixing finely divided tellurium with exsium bromide in dilute hydrobromie acid, then adding bro- mine in excess. The presence of free acid is necessary to pre- vent the separation of tellurous acid. When the tellurium has disappeared, the solution is concentrated by the aid of heat, and, on cooling, bright red crystals of the pure salt are depos- ited. These are generally somewhat larger than the erystals of the double chloride. Analysis gave: Calculated. CS. si pee 30°90 30°87 30°91 30°54 Lem Soar 14:29 13°60 14°08 14°55 Brees 55°'01 eens 55°32 55°11 * loc. cit. with Potassium, Rubidium and Cesium. 275 This salt remains unaltered in the air. It can be separated from its solution in dilute hydrobromic acid by the addition of concentrated acid. It does not melt below the boiling point of sulphuric acid. Attempts to prepare a hydrous salt according to the methods used for the preparation of TeBr, 2K Br. 2H, O were without success. Rubidium telluribromide, 9RbBr. TeBr,—The directions given for the preparation of the corresponding ceesium com- pound apply also in the preparation of this salt. If the solu- tions are strong, the compound separates as a bright red pre- cipitate, but if dilute, on concentrating by means of heat or spontaneous evaporation, it crystallizes in brilliant red octa- hedra. Analysis gave: Calculated. | | oye es 22°02 22°04 4 eye Cah ae ae pas 16°11 1B cut ken Rae ee 62°07 61°85 This salt is stable in the air. Like the corresponding cesium salt, this separates from its solutions by the addition of concen- trated hydrobromic acid. When it is dissolved in a little water and the solution is cooled slowly, colorless octahedrons of TeO, separate. The latter product was found to be im- pure, containing a small amount of bromine. On heating, the salt decrepitates slightly and melts at a high temperature. Efforts to prepare a hydrous salt according to the methods used for the preparation of 2K Br. TeBr,.2H,O were without success. Potassium telluribromides, 2K Br. TeBr, and 2K Br . TeBr,. 2H,O.*—¥or the preparation of these salts, a mixture of the constituents was made as described in the case of the cesium double bromide. The solution invariably deposited erystals of the anhydrous salt when it had been concentrated by heat, but, by spontaneous evaporation of the filtrate, the hydrous salt was obtained. On recrystallizing either of these salts from water or from dilute hydrobromic acid, the anhy- drous salt is obtained when the solution has been saturated by boiling and then allowed to cool, but if the solution is left to deposit crystals at ordinary temperature the hydrous modifica- tion is obtained. The crystals of these different compounds closely resemble each other in color and appearance. The anhydrous variety crystallizes in octahedrons modified by the cube. The orthorhombic crystals of the hydrous salt look like distorted crystals of the other. This being the case, and since * Described by Von Hauer as containing three molecules of water of crystalliza- tion. AM. JouR. Sc1.—TuHrrD Series, Von. XLV, No. 268.—APRIL, 1893. 20 276 HH. L. Wheeler—Double Halides of Tellurium the erystals of the hydrous compound can be obtained much larger than those of the anhydrous salt, both Von Hauer and Wills selected these for their work, while the more easily ob- tained anhydrous salt was overlooked. The hydrous salt is readily distinguished from the anhydrous one by its deport- ment on exposure to a dry atmosphere. The latter is stable, but under these conditions the hydrous compound rapidly eftloresces, losing its luster, the faces of the crystals becoming superficially covered with a light reddish yellow and opaque layer of the anhydrous salt. Crystals which had been ex- posed to dry air for several days and were completely covered with this layer were found, on crushing, to remain unaltered in the interior and to have still retamed included water in addition to their water of crystallization. This was shown by the fact that the crushed crystals gave a stain of the mother liquor to filter paper. This property of the hydrous crystals explains why Von Hauer assigned three molecules of water to this salt instead of two. The material for analysis of the hydrous salt was selected from crystals varying in size from 7 to 138™" in diameter. These were very rapidly crushed on smooth filter paper, to remove included water, and immediately corked up in the weighing tube and analyzed. A close exami- nation of the fragments, before and after weighing, gave no evidence of loss of water from the substance by efflorescence. The analyses were from three different crops. Calculated for Calculated for Analvsis gave: 2KBrTeBr:.2H20. 2K BrTeBr,.3H,.0. Kee e090 11°07 10°73 10°87 10°61 Ter Weg 17°29 17°46 17°38 16°96 BYE oaks SRS 66°36 66°34 66°74 65:1) HOF 5:33 5°53 a3 5°01 BD These results make it evident that the salt contains two molecules of water, and not three as has generally been sup- posed. The water in this salt was determined by heating it in an air bath to constant weight. The temperature was main- tained between 150°-160°, and finally, to be sure that all the water had been driven off, the residues were analyzed in two cases. Calculated for Analysis gave: 2K Br. TeBry. KG ais aie ek Ne ifall 11°52 11°44 Mein gases 18:29 18°58 18°30 Brigee att 70°25 70°09 70°26 Analyses of products obtained by cooling hot saturated solu- tions gave the following results: with Potassium, Rubidium and Cesium. 277 Caleulated for 2K BrTeBr,. 15S eee 11°67 WL 7K0) Sane! 11°44 ahem 18206 he ities 18°30 Bir fe eh 70°24 70°20 69°40 70°26 The Double Todides. . These salts are all black. The powder of the cesium salt is pure black, that of the rubidium and potassium salts is grayish black. Cesium telluriiodide, 20sI. TeL,.—In order to prepare this salt, and also in the case of the rubidium and potassium com- pounds, tellurium tetraiodide was made by treating tellurous oxide with hydriodic acid. The iodide of tellurium is spar- ingly soluble in hydriodic acid, but, on mixing this solution with a solution of czesium iodide, an amorphous black precipi- tate was obtained, even in very dilute solutions. Calculated for Analysis gave: 2Csl. Telus. ( GPS a ate 23°37 23°07 Aeterna 10°51 10°84 Re ee 65°17 66°09 This compound resisted all attempts to prepare it in a erys- talline form. It is insoluble in cesium iodide and in hydriodie acid, hence warming in the mother liquor failed to dissolve the salt. It is decomposed slowly by cold water, rapidly by hot, and apparently tellurous acid or anhydride separates. This generally is impure, being mixed with a dark colored residue containing iodine. On exposure the salt slowly loses iodine. In the open capillary it does not melt below the boiling point of sulphuric acid. Rubidium telluriiodide 2RbI. Tefl,,—This compound was prepared by mixing the constituents in the same manner as in the preparation of the corresponding ceesium salt. If the solu- tions are only moderately concentrated, a black amorphous precipitate is produced. Unlike the corresponding cesium salt, it dissolves, toa slight extent, on warming in the mother liquor, and on cooling, black microscopic octahedrons are pro- duced. Calculated for Analysis gave: 2Rb1. Tel. 18910) eer eae yes 16°83 16°17 Meus) on caer 11°81 eee teamed cyt W207 (EO This iodide is stable on exposure. Water effects the same decomposition as in the case of the cesium salt. A small por- tion of this salt dissolves in strong alcohol, giving the color of a weak iodine solution. 278 H. L. Wheeler—Double Halides of Tellurium Potassium tellurviodide, 2KI. Tel,.2H,O. — This com- pound can most conveniently be prepared by boiling tellurium iodide in a strong solution of potassium iodide in dilute hydri- odie acid. The solution, filtered while hot from any undis- solved tellurium iodide, deposits long black prisms on cooling. These crystals attain considerable size, about 30™™ in length, when a large excess of potassium iodide is used. The mother liquor, on evaporation in a desiccator, deposits more of the salt, but the crystals have a different habit. Caleulated for Analysis gave: 2K1. Tel,. 20. ICG SIT. ke 8°41 8°70 8°39 7°81 Mew ie lie ht: 12°25 12°95 12°30 12°48 eee DOT Siar 76°68 76°11 ET OA is LO 3.57 su Epa 3°60 For the determination of water in this compound the crys- tals were rapidly pressed on paper and immediately analyzed. It was found that the salt could be dehydrated at a tempera- ture between 110°-115°, the resulting anhydrous salt being stable at that temperature. This was shown by an iodine determination in the residue. Analysis gave 78°78 per cent. of iodine, calculated for 2KI. Tel, 78-94. This salt is far more stable in the air than the corresponding bromide, but the erystals lose their luster in dry air, becoming dull black on account of a superficial efflorescence. Crystallography. The erystallization of the anhydrous alkali-tellurium halides is isometric. The chlorides were obtained in octahedrons with little or no modification, the bromides in combination of octa- hedron and cube. The chlorides and bromides were measured and also proved to be isotropic by examination in polarized light. Of the anhydrous iodides, the rubidium salt was the only one obtained in crystals, and these were too small to measure, but appeared under the microscope as combination of octahedron and cube. They were so opaque that they could not be tested in polarized light. The two hydrous salts, 2K Br. TeBr,.2H,O and 2KI. Tel,. 2H,0 although analogous to each other in their composition, differ in crystallization. The bromide is orthorhombic as has been shown by Baker* also by Grailich and Lang in Rammels- berg’s Handbuch.+ That the hydrous potassium tellurium bromide obtained in the present work is identical with that described by the above authors is shown by measurements of the crystals. The crystallization of the salt 2K1.TelI,. 2H,O is * Loe. cit, t Loe. cit. with Potassium, Rubidium and Cwesium. 279 monoclinic. Two different habits were observed ; long prisms, developed in the direction of the clino axis were obtained from hot solutions (fig. 1). The mother liquor from these, on standing, gave shorter prisms in which the domes and clino- pinacoids were wanting (fig. 2). The; forms observed were: m 110 ce 001 d 031 p 111 b 010 The axial ratio is as follows: d:b:¢ 7047; 1; 5688 B= 100,001 = 59° 7' 16” The crystals gave fair reflections of the signal on the goniometer. Measurements chosen as fundamental are indi- cated by an asterisk. Calculated. Measured. mam 110,110 62° 20’ 62° 267 mab 110, 010 58° 50’ 58° 507 * bac 010, 001 90° 90° MAC 110. 001 63° 57 63° 577 * map 1104111 60° 497 60° 427 * CAD 001,111 BT NG Domne a bad 010 . 031 34° 207 34° 25' bap 0104111 GiletoaAgn4 Giline4 203.024 mam INO. IO 117° 407 117° 33° can 0014110 NG? . By 116° 11/ The crystals were too opaque for any optical examination. In conclusion the author wishes to express his indebtedness, to Prof. H. L. Wells for valuable advice and for the interest that he has taken in this work, and to Prof. 8S. L. Penfield under whose direction the crystallography of these salts was investigated. Sheffield Scientific School, January, 1893. 280 Headden—Tungstous Oxide, new Oxide of Tungsten. Art. XX XIII.—Tungstous Oxide—a new Oxide of Tungsten associated with Columbous Oxide ;* by WM. P. HEADDEN. In an article on some tin and iron compounds, an abstract of which appeared in this Journal,+ reference was made to certain products as iron bottoms whose formation was then discussed at sufficient length. This paper is practically a study of the residues obtained from those bottoms. The residues as obtained after having been freed from car- bon and the portion which was so fine that it remained in suspension for a longer time, consisted of two parts, a heavier and alghter. The specifically lighter one was quite readily attacked by hydric nitrate and the whole of the residues from the first two bottoms were treated with this salt in order to obtain the heavier portion as pure as possible. The final residue from the first bottom was a brownish gray, very fine, crystalline, and wholly non-magnetic powder which under a magnification of 140 diameters, appeared to consist of prisms. It was examined after being ignited and found to contain columbiec acid with a small quantity of tungstie acid and a very little iron and tin but no tantalic acid. The residue from the second bottom was treated in a like way. The solution obtained by treating it with warm dilute hydric nitrate indicated the presence of compounds of tin and iron rich in the latter element. The tin went into solution and a small quantity of tungstic acid was formed ; but it is uncertain whether it was derived from the soluble compounds or from the portion which remained as insoluble. I think that it was derived from the latter. The gray, crystalline residue, insoluble in warm dilute hydric nitrate was treated successively with cold concentrated hydric nitrate, aqua regia, water, and aleohol, and gave when subsequently treated with cold concen- trated hydric chloride sp. gr. 1-2 a deep blue but clear solu- tion, whose color was discharged by dilution with water and also upon being heated. The greater portion of this residue was strongly magnetic, the rest of it, however, was not at- tracted by the magnet. I could observe no difference in the form of the grains and crystals in the two portions. These were divided, by carefully washing them, into a finer erystal- line and a coarser, well crystallized portion. The erystals are triangular prisms whose height is often several times the alti- * Abstract of an article read before the Colorado Scientific Society, January meeting, 1893. + Vol. xliv, p. 464. Headden—Tungstous Oxide, new Oxide of Tungsten. 281 tude of their triangular bases but not always so, as the prisms are sometimes very short. The triangular base is apparently equilateral and [ interpret the form as a hemiprism belonging to the hexagonal system; the color is gray to tin-white and the luster is brilliant metallic. These crystals are sometimes grouped in clusters and then the larger ones are often invested with an abundance of smaller ones. Cases of penetration are frequent but no surfaces other than those indicated have been observed. Some of the crystals are striated, which is probably due to interference. The magnetic portion of this second bottom, as used for analysis, consisted for the most part of crystalline particles. It oxidized slowly and imperfectly when fused with potassic hydrie sulphate, but when heated to dull redness in an open crucible it ignited and burned to a voluminous powder, yellow while hot but nearly white when cold. Complete oxidation is effected with some difficulty. The results of the analysis No. I were: At. eq. Cheeses Sid, 40°13 10 14 1 VW eee Se oy 15°80 x iBlepse Mats Gru 19°62 35°10 9 Silene one ae 5°04 ALOT 1 4 14 1 (O60 =) ar oa gare 8°78 54°90 1 100°20 This suggests a mixture of 10CbO+4WO+Fe,Sn. Such a mixture would require 24°42 per cent of its weight of oxygen to completely oxidize it; the amount absorbed upon ignition was 24°88 per cent of its weight.* The non-magnetic portion, analysis No. II, gave *Jn separating tungstic and stannic oxides from columbiec acid by digesting with ammonic sulphide and adding hydric chloride or sulphate to the alkaline solu- tion, I have frequently obtained a yellow filtrate in which a further addition of hydric sulphate produced no precipitate. This reaction is due to the presence of potassie oxy-sulpho-tungstate K,WO.S. which is formed by the action of the ammonic sulphid on potassic tungstate formed during the fusion. The extent to— which this salt may be formed is shown by the fact that in one instance I ob- tained rather more than one-third of all the tungstic acid present in this yellow filtrate from the mixed sulphide precipitate. This salt ig given in Gmelin-Kraut’s Handbuch der Chemie, vol. ii, Part IT, page 126, as being sometimes met with in the preparation of tungstic sulphide by fusing together potassic tungstate and sulphur—Berzelius; the same state- ment is given in Watt’s Dictionary of Chemistry, vol. v, p. 914. But the reac- tion is not recorded anywhere, so far as I can find, as produced in the manner here given. 282 Headden—Tungstous Oxide, new Oxide of Tungsten. At. eq. Ohya eta 48°56 5156 LO; ae ee W cic 2o-2187:64 20:46, )) 4:00) 0 i nr Here aae ete Bey Dial 13's) Se eect 0°72 0°61 0°12 Oa ET es eae 10°08 63°00 12°60 12°60 1 100°22 The gain upon ignition amounted to 22-00 per cent of its weight. The formula suggested is the same as in the preced- ing case. The third bottom showed, after a portion of it had been dissolved in hydric chloride, the triangular crystals dissemi- nated throughout the mass and particularly abundant at the bottom. The residue in this case was not treated with warm hydrice nitrate but was divided into three parts numbered 1, 2 and 3, beginning with the lightest. PART 1. An analysis showed that this portion was a mixture of oxides and the ratio given for the metais to the oxygen was 1:1. When digested with cold hydric chloride, sp. gr. 1:2, it gave a clear blue solution whose color was discharged upon addition of water. The action of aqua regia upon it pre- sented two phases, the first was very violent, while the second was quite slow; this was due to the fact that this reagent first dissolved the iron-tin compounds present, and then the tungs- ten or its compounds, which is evident from the following: some of this material was digested with two successive por- tions of aqua regia, each portion was evaporated to dryness after digestion at a gentle heat for about an hour; the first treatment gave 185°7™&" Fe,O, and 81:0™s"™ WO,, the second treatment gave 6-7™e" Fe,O, and 51:0™" WO,. The residue from the first treatment consisted of triangular prisms, with a few crystalline grains, that from the second of remnants of such crystals, and after ignition consisted of tungstic acid with a small amount of columbic acid.* Parr 2. This consisted of crystalline grains and crystals. The latter were triangular prisms with an occasional six-sided plate; these plates which were relatively long and wide, were always pitted and had a much darker color than the prismatic crystals. The analysis of this showed 66°66 per cent of it to be difficultly soluble in aqua regia and emphasized the fact that the iron and tin do not belong to the triangular prisms which make up the larger part of the insoluble portion. * In treating this portion with aqua regia containing a large excess of HCl, I obtained a clear yellow solution which gave upon addition of water a precipitate of tungstic acid; reference will be made to this reaction again. Headden—Tungstous Oxide, new Oxide of Tungsten. 283 The remainder of part 2 was persistently boiled with slightly diluted hydrie nitrate, which attacks the iron and tin com- pounds much more readily than it attacks the crystals. The residue after being purified amounted to 42 per cent of the original quantity taken. Neither the mixture itself nor the purified residue impart any color to a boiling concentrated solution of potassic hydrate, nor is there any evolution of ammonia or other reaction, but if the crystals are first digested with cold aqua regia and then potassic hydrate be added, the solution becomes brown upon standing, probably due to the formation of WO,. The puri- fied residue consisted very largely of the triangular prisms ; some of the crystalline aggregations remained and the six- sided plates were still recognizable. When heated in the air it did not ignite but was slowly converted into a yellow pow- der. This residue was analyzed with the following results. Analysis IIT. | At. eq. Clie 16-56 6°98 4°9 ) 12] NCB dest ll 76°12 41°37 29-1 j = 1 Sh Gee ee Ae 9°06 16°18 11:4 Slee oe OS 1°42 1:0 On. Ser: 6°34 39°63 28:0 i 99°76 The gain upon ignition equalled 20°66 per cent. If we cal- culate the columbium, tungsten and oxygen to one hundred we obtain Cb 7°37, W 85:57, O 7:12 = 100-00. Portion No. 3, that is, the coarsest portion of the residue, was passed through a 148 mesh bolting cloth and the small portion which remained on the cloth was reserved for subsequent study. The portion used for analysis consisted of triangular prisms, which constituted as much as and possibly more than 85 per cent of the whole mass; the rest was made up of crys- talline aggregations with a few of the six-sided plates noticed in the last sample. When ignited in the air it oxidized with- out incandescence to a yellow powder; the gain equalled 19°10 per cent; the analysis No. 1V gave: At. eq. Cleese 1°46 1°55 1°34 ) 9 ‘29 Ve Sigh Set 86°64 47°09 40°94 aoe ee es sheu a ate 4°32 etl 6°70 Sees seh e136 eI) 1:00 (0 yes lei aed 6°32 39°50 34°35 34°35 1:00 284 Headden—Tungstous Oxide, new Owide of Tungsten. This and also the preceding analysis indicates an excess of tungsten over that required by the oxygen for the formation of tungstous oxide. But if there remained any metallic tung- sten in the regulus we would expect to find it here; because of its high specific gravity and the fact that careful washing was the only available method for separating and purifying the portions into which the residues were divided. Boiling the material on which analysis No. III was made with hydrie nitrate had no effect upon this point as columbous oxide and metallic tungsten are either only very slowly attacked or not at all acted upon by this agent. Relative to the probability of the presence of metallic tung- sten in these iron bottoms I would repeat the statement that they are closely related to cast iron and others have observed that metallic tungsten may exist as such in cast iron. Further, the result of much labor in an endeavor to obtain columbous oxide directly from a mixture of columbite, magnetite, and stream tin containing wolfram, was a series of iron bottoms which when melted together and subsequently dissolved in hydric chloride yielded a small quantity of a well crystallized residue in which, neglecting a minute quantity of iron, tung- sten was the only metal. The crystals were octahedral, appar- ently quadratic, with some six-sided plates similar in color, luster, and in being pitted to those observed in portions two and three of the residue form the third bottom. Most of the octahedral faces were smooth but on some crystals these faces were depressed at the center. These crystals when kept at a bright red heat for half an hour in an open crucible were only very slightly oxidized and appear to be metallic tungsten.* As the components of these various products could not be satisfactorily distinguished, even with the aid of the micro- scope, we are compelled to have recourse to the study of those ratios which remain constant while others vary. We may divide the results obtained in analyses one and two into two groups, one containing the iron and tin, and the other, the columbium, tungsten, and oxygen. The iron and tin together constitute 25 per cent of the first sample and rather less than 4 per cent of the second, but the ratio of the iron to the tin is the same in each. If we caiculate these ele- ments found in each analysis to one hundred we obtain for * The ignited crystals themselves were not soluble in hot hydric chloride, sp. gr. 1:2, but the ignited mass gave with this salt a yellowish solution which solidified on being poured into a cold beaker, to a buttery mass, which proved to be pure - tungstie acid. This is the second instance in which I have found tungstic acid to be soluble in hydric chloride. The statement in Gmelin-Kraut’s Handbuch der Chemie, is that *‘ Acids, even concentrated sulphuric acid, do not dissolve it,” i. e. WOs. Its solubility in acids has been observed but once before this so far as I can find, i. e. by J. W. Mallet. Headden— Tungstous Oxide, new Oxide of Tungsten. 285 number I: Fe 80:47 per cent, Sn 19°53 per cent, for number Ti: Fe 81:72 per cent, Sn 18:28 per cent. The ratios ob- tained for the remaining elements are quite as satisfactory and represented in the same manner are as follows: No. I. No. IT. (Qlovesien Sager’ 49°91 6] SR ties 50°44 Ver ee ne DB os42 AVA Eereesron Rare 39°09 Oe te cae LG) 7 Oa ee a tiatah aE 10°47 100°00 100°00 The percentage composition required by the mixture 10CbO0+4W0O is Ch 49°473, W 38°737; O 11:890. The prop- erties of this mixture agree closely with those of columbous oxide especialiy in burning with imcandescence to columbic acid. The presence of the triangular prisms is quite conclu- sive that the columbium and tungsten are present in separate compounds, which will appear more fully further on. The two remaining analyses are not comparable to the same extent as those just given, still Nos. I] and 1V give 1:1:21 and. 1:1:22, respectively for the ratios of the colum- bium and tungsten to the oxygen. While it is inferable from the results of analysis III that the tungstic acid in the other analyses was derived from the prismatic crystals, the most conclusive proof that these trian- gular prisms are crystals of a compound of tungsten with only a very little or no iron or tin is afforded by the material desig- nated part I of the residue from the third bottom; for upon being treated with aqua regia in successive portions it yielded upon the first treatment a solution carrying ferric oxide equal to 2°3 times the amount of tungstic acid formed while the sec- ond treatment produced an amount of tungstic acid equal to 73 times the amount of ferric oxide which went into solution. The residue from the first treatment was very largely made up of these triangular crystals. We conclude from all of this that this hemiprism is the usual erystal form of the compound of tungsten which occurs in these residues. This conclusion is supported also by a comparison of the results obtained in analyses II, III and IV with the respective materials on which they were made. The material serving for analysis No. II was a fine crystalline powder with some triangular crystals ; that serving for No. III contained very many of them, while in No. IV I estimated them as forming upwards of ‘85 per cent of the mass. The results of the analyses are IL. III. IV. Ch._..-_. 48°56 per cent. 6°56 per cent. °1:46 per cent. Were Sa eI tage OSes 86°64 286° Lindgren and Melville—Sodalite-Syenite Analyses Nos. I and II give the ratio of 1:1 for the atomic ratio of these metals to the oxygen, and Nos. III and IV give approximately the same, from which it appears that we havea mixture of columbous and tungstous oxide in these residues and that the triangular prisms are crystals of the latter. Tungstous oxide—W O—as thus obtained erystallizes in the hexagonal system, mostly in hemiprisms having a light gray to tin white color, a metallic luster, a hardness greater than glass, and a dark gray streak. Hydric chloride, fluoride, and sulphate, also a boiling solution of potassic hydrate have no perceptible action on it, but hydrie nitrate and aqua regia attack it, especially when heated, converting it slowly into tungstic acid. The crystals can be kept under water or exposed to the air at ordinary temperatures without change, but when heated to redness in the air they are gradually con- verted into tungstic acid; this change takes place without incandescence but is accompanied by a considerable increase in volume, less, however, than that which accompanies the corresponding conversion of columbous oxide into columbic acid which is accompanied by incandescence. The tungstous oxide was probably formed in this case by the action of stannous oxide, formed in the repeated liqua- tions of the tin, upon metallic tungsten which had been re- duced in the original tin charge. State School of Mines, Rapid City, S. D. Art. XXXIV.—A Sodalite-Syenite and other Locks from Montana; by WALDEMAR LINDGREN, with Analyses by W. H. MELVILLE. AMONG the collections in the U. S. National Museum there is a suite of specimens, principally of eruptive rocks, collected — in the northern part of Montana, by Dr. C. A. White and Mr. J. B. Marcon during the summer of 1883. The principal localities where the collections were made are the Moccasin Mountains, the Bear Paw Mountains, and Square Butte, near the Highwood Mountains. Rocks from these places have not been previously examined, as far as I know, and it is only pro- posed in this paper to describe in detail one which appears of particular interest; the general character of the collection, however, may be briefly noted. All of the igneous rocks collected appear to belong to the class of post-Cretaceous intru- sive rocks which has such a wide distribution in the Rocky Mountains and which range from the most acid to the most and other Rocks from Montana. 287 basic composition. Dr. C. A. White has had the kindness to furnish me with information regarding the occurrence in the field of the rocks and all the statements in the following pages in reference to this are from his unpublished notes. The Moccasin Mountains form an isolated group about seventy miles southeast from Fort Benton on the eastern side of Judith river. They consist, according to Dr. White, of a central core of eruptive masses, probably laccolitic in charac- ter, surrounded by a ring of upturned sediments ranging from the Cretaceous to the Carboniferous. The rocks from the central core appear to belong only to one type. They are light colored, gray or yellowish porphyritic rocks with large phenocrysts of sanidine and soda-lime-feldspar, and smaller ones of brown hornblende; a greenish augite is occasionally seen. The groundmass is always holocrystalline of more or less fine grain and consisting of unstriated feldspar and quartz which sometimes are intergrown in such manner that each quartz grain contains numerous smaller feldspar grains of irregular optical orientation.* These intrusive rocks from the Moccasin Mountains appear almost identical with the laccolitic masses in the Carboniferous of the Little Belt Mountains and the dikes in the Cretaceous east of Cadottes pass which I have described in previous papers under the name of dacites and diorites. + Again, very similar rocks have been described in detail by Mr. Whitman Cross from Leadville and other localities in Colo- rado, and by Mr. Iddings from the Yellowstone Park region. It is apparent that this type of porphyritic intrusive rock is of wide-spread occurrence in the Rocky Mountains ; the name of porphyrite or quartz-porphyritet{ is now usually applied to them. The Bear Paw Mountains are situated sixty miles northeast of Fort Benton and rise about 2500 feet above the surround- ing plains. According to Dr. White, they are largely made up of igneous rocks intruded in Cretaceous strata. The speci- mens which are taken in the broad valley of Eagle creek at the south base of the mountains, mostly from dikes or dike- like masses, show a very different type from the one just described. Prevailing is a dark fine-grained porphyritic rock with phenocrysts of greenish idiomorphic augite up to three milli- * The name of micro-poikilitic has recently been suggested by Mr. Iddings for this structure. + 10th Census, vol. xv, pp. 720 and 731. Eruptive rocks from Montana; Proc. Cal. Acad. Sci., series II, vol. iii, p. 39. t The definition of porphyrite as applied to this type of rocks is given by Mr. Iddings in his paper on ‘The Eruptive Rocks of Electric Peak and Sepulchre Mountain.” 12th Ann. Rep. U.S. Geol. Survey, p. 582. 288 Lindgren and Melville—Sodalite-Syenite meters long and flakes of a brown, slightly pleochroie mica with very small axial angle. The groundmass consists mostly of lath-shaped plagioclase erystals together with augite and mica. In some specimens with phenocrysts of olivine and augite the groundmass is glassy and contains no feldspar; this rock approaches closely to certain limburgites. The general appearance of the Bear Paw series and the absence of pheno- erysts of feldspar in it points to its connection with the group which Rosenbusch has called the lamprophyric dike rocks. The suite of specimens collected at Square Butte is of par- ticular interest. Square Butte, which really forms the eastern end of the Highwood Mountains, is situated thirty miles southeast of Fort Benton and eighteen miles nearly due east of Highwood Peak. The rocks from this locality show a close relationship with, those from the main group of the Highwood Mountains, and it may perhaps not be amiss to refer briefly to the character and rock types of the latter.* The Highwood Mountains with their sharp and jagged peaks and ridges stand in isolated grandeur on the monotonous plains twenty miles south of Fort Benton on the Missouri river. They form an oblong group twenty miles from north to south and thirty miles from east to west and their highest peaks rise 3600 feet above the surrounding Cretaceous plateau which here consists of the nearly horizontal black shales of the Fort Benton group. The mass of the mountains is made up of a network of dikes and probably also of laccolitic masses between which are included contact metamorphosed and disturbed remnants of sediments none of which are be- lieved to be older than the Cretaceous. Above the Fort Benton group once rested the whole thickness of the Montana and Laramie formations or at least 8000 feet of sediments. Voleanic activity began at this point at or after the close of the Cretaceous period. Great quantities of igneous rocks were forced into the sediments and on the surface the eruption was probably connected with the phenomena of a subaerial vol- cano. Subsequent erosion has removed nearly the whole thickness of the softer Laramie rocks, exposing the harder core of the ancient voleano and the abyssal rocks solidified under a pressure of many thousand feet of superincumbent sediments. The Highwood Mountains are very similar in structure to the Crazy Mountains, also in Montana, recently described by * The general geology of the Highwood Mountains has been described by Prof. W. M. Davis in 10th Census, vol. xv, p. 697, and the petrography by W. Lindgren, loc cit., p. 729. See also, “‘ Eruptive Rocks from Montana,” by W. Lindgren. Proce. Calif. Acad. Sci., series JI, vol. iii, p. 40. and other locks from Montana. 289 Mr. J. E. Wolff,* but the petrographical character of the two voleanic districts is somewhat different. The intrusive rocks of the Highwood Mountains are in general basic in composition and holocrystalline in structure. There are a few coarsely granular rocks, principally dikes of augite syenites, but a much more common type of rock is of a porphyritic structure and closely allied to the trachytes.+ ‘Augite-trachytes are frequent, usually containing two gene- rations both of the orthoclase and the augite. The latter is characterized by a deep green color and evidently contains an admixture of the acmite molecule. The quantity of angite in these rocks is sometimes very large, and they grade over into basaltic rocks with orthoclase, plagioclase, olivine and augite. Attention should be called to the great similarity of these rocks with the peculiar intrusive and extrusive masses recently described by Mr. Iddings from the Crandall basiv and the Absaroka range in the National Park region. Another interesting type in the Highwood Mountains is that of the analcite-basalts which, with holocrystalline porphyritic structure, consist of augite, olivine, brown mica and analcite. The latter mineral here appears under conditions strongly sug- gesting a primary origin. Square Butte and vicinity was not visited by me in 1883, and lam again indebted to Dr. C. A. White for notes regarding it. As already mentioned, it forms the extreme eastern part of the Highwood Mountains with which it is connected by several lower buttes and ridges. The elevation of the flat top, about three-quarters of a mile in diameter, is 5600 feet above sea level according to the maps of the Northern Transcontinental Survey (Fort Benton sheet, U. S. Geol. Survey). The Butte is composed of a light gray eruptive rock with very distinct lamination. In the elevated table land surrounding its base are found several horizontal sheets of a dark gray or black voleanie rock interbedded with black Cretaceous shale be- longing to the Fort Benton group. There are three distinet sheets of this dark rock, each about eight feet thick and separated by beds of shale of about the same thickness. Surrounding Square Butte there are numerous dikes apparently radiating from the central mass. The dark volcanic sheets are represented in the collection by three types. Unfortunately, most of them are very much decomposed. The first is porphyritic and contains as pheno- erysts augite of the Highwood type, olivine, usually brown * Bull. Geol. Soc. Amer., vol. iii, p. 445. + This term is here used without restriction to surface flows. | ¢ The Origin of Igneous Rocks, by J. P. Iddings. Phil. Soc., Washington, WaCe voleexii, py 169) 290 Lindgren and Melville—Sodalite-Syenite mica, and lastly white isometric crystals up to two millimeters in diameter. The original character of these white erystals cannot be made out as they are completely converted into secondary aggregates. The groundmass, which is quite fine- grained, contains much augite, besides other indeterminable minerals. The second type is similar to the “ analcite-basalts,” but the specimens are not fresh and the white mineral is again com- pletely decomposed. This type is more coarsely crystalline and not so pronouncedly porphyritie. The third type is coarsely granular and in composition ap- proaches the theralite described by Mr. J. E. Wolff from Mar- tindale near the Crazy Mountains. The main mass of Square Butte is represented by a light yellowish grey, rather coarse grained granular rock of miarolitic appearance (No. 28705, U. S. National Museum, Summit Square Butte). Macroscopieally it consists of grains and broad lath- shaped erystals of feldspar, often five millimeters long, black glistening hornblende prisms reaching three millimeters in length, and sodalite which appears as small grains of a pale brownish color. Under the microscope the rock is shown to be hypidiomorphic granular and the following constituents are noted in their order of formation: apatite, hornblende, orthoclase (with some plagioclase), sodalite, and anatlette. Sodalite-syenite magnified 7 diameters. A hornblende, B orthoclase, C sodalite, D analcite. The predominant constituent is orthoclase, occurring both as irregular grains and lath-shaped crystals; individuals partly or wholly imbedded in sodalite show terminal faces. Many of and other Locks from Montana. 291 the grains are very clear, but the larger part are somewhat clouded, not, however, by decomposition and the formation of muscovite and kaolin, but principally by irregular and elonga- ted gas inclusions together with others of indeterminable char- acter. Small crystals of apatite, as well as green and brown hornblende microlites, are noticed in the feldspars. A triclinic feldspar with very fine twinning lamellee in only one direction occurs in intimate, almost microperthitic intergrowth with many of the orthoclase grains. This triclinic feldspar which usually is more pellucid than the orthoclase has every appear- ance of being albite. Many of the feldspar grains are corroded in a peculiar man- ner as shown on the figures and are filled with faintly doubly refracting analcite. ‘The same corrosion has been observed in an augite-syenite from the Little Belt Mountains,* although the enclosed mineral was not then recognized as analcite; a comparison with the Square Butte rock shows beyond doubt the identity of the two minerals. It has also been noted by J. Francis Williams in similar rocks.+ This analcite is doubtless derived from the albite. It is a curious fact that although there is abundant sodalite present in the rock it should have remained fresh and undecomposed while the albite was attacked. There are no other zeolites or products of decomposition and it ap- pears as if this conversion into analcite would have taken place very soon after the solidification of the rock. It certainly can- not here be regarded as a product of ordinary decomposition. Prof. Bréggert and other authors have shown that analcite, in general, is the earliest of all the zeolites and that 1t must have been formed at a relatively high temperature, that is, perhaps between 200° and 400°. Friedel and Sarasin§ for instance obtained analcite by heating the constituents of albite with water to 400°. In order to test the character of the feldspars, fragments were introduced into a Thoulet solution. The feldspars began to sink at sp. gr. 2°57 and continued to fall until a sp. gr. of 245 was attained. Two portions were subjected to partial analysis : Sp. gr. 2°57 Sp. gr. 2°55 Na,O 6:08 3°88 KE Ors 8:91 11°03 2 It is evident that the first portion is orthoclase with a strong admixture of albite and equally so that the second is a nearly * Eruptive Rocks from Montana, loc. cit., p. 46. + Ark. Geol. Survey, 1890, vol. ii, p. 79. + Zeitschrift f. Kryst. u. Miner., xvi, p. 169. § Compt. rend. 1883, xcvii, 290. Am. Jour. Sc1.—Tsirp Serres, Vou. XLV, No. 268.—ApRIL, 1893. 21 292 Lindgren and Melville—Sodalite-Syenite pure orthoclase. The analcite which penetrates the feldspars is the cause of the lowering of the specific gravity ; a mechan- ical separation of the two minerals is hardly practicable. The hornblende occurs as slender black prisms bordered by «xP and «Px ; terminal faces are not seen. It is idiomor- phic both against the orthoclase and the sodalite. The color in thin section isa very dark brown, so dark in fact that in slides of ordinary thickness many crystals are only faintly translucent. The pleochroism is very strong; the rays vibrating parallel to c and bare both very strongly absorbed, producing a dark brown color, while those vibrating parallel to the axis of maxi- mum elasticity are less absorbed with a yellowish brown color, sometimes showing a tinge in green. The axis of minimum elasticity is inclined to the principal axis at an angle not ex- ceeding 13°. In some places the brown hornblende is under- going a peripheral conversion into a green modification with an extinction up to 25°.* The specific gravity of the horn- blende was found to be 3°437. From the characteristics men- tioned above the identity with Prof. Brégger’s barkevikitet seemed highly probable and to confirm this a quan) was isolated and analyzed. II. Barkevik. I. Square Butte. Analyzed by G. Flink. H,O (above 100°) 0:24 SIOLEL aa wane 38°41 42°46$ PENT OA i renee 17°65] 11°45 BeiOl eee Bae 3°75 6°18 He@ gis? see as 21°75 19°98 INGO get sn cape fe, trace Min @Oypeea ae shee 0°15 0-75 CaO: espe ese ie 10°52 10°24 Mo @ze -ne em 2°54 Ticatelt Na Ol casa eee 2°95 6°08 KiOe cece Bae: 1°95 1°44 9979) 99°64 The mineral - differs from barkevikite, an analysis of which is given under II, in containing sonnear hat less silica and alka- * The conversion of brown compact hornblende into a green fibrous modification was first observed by Mr. G. F. Becker, in his ‘‘Geology of the Comstock Lode,” Monogr. II], U. 8. G. 8., p. 36, Washington, 1882. The same change has been noted by Mr. F. Becke and Prof. G. H. Williams, Bull. 28, U. 8. Geol. Survey, p 45. + Z. f. Kryst., u. Min., xvi, p. 412. t+ The titanic acid in (I) is contained in the alumina. The rock carries 0°29 per cent TiO. and contains 23 per cent. hornblende; hence, there being no other titanium minerals present, the TiO. in the hornblende may be calculated at 1:26 per cent which would reduce the alumina to 16°39 per cent. § With some TiO». and other Rocks from Montana. 293 lies, while the alumina is higher. The low percentage of CaO and MgO and the high amount of FeO show, however, that it is very closely related to it. In the absence of any erystallo- graphic orientation the only way of distinguishing it from arfvedsonite is by its color and streak. I believe this is the first time that barkevikite has been identified in the United States. The hornblende in the pulaskite,* described by J. Francis Williams, also a syenitic rock, is probably closely related to barkevikite, but no analysis was made of it. The sodalite forms irregular grains and partly developed erystals ; it is allotriomorphic against the feldspar, but usually idiomorphic whenever bordering on the analcite. It some- times fills triangular interstices between the lath-shaped feld- spars. The period of its consolidation seems here to be decidedly later than that of the feldspar. The cleavage paral- lel to & 0 is well indicated by the arrangement of very numer- ous inclusions in part of gas, in part of liquid with very large air bubbles: frequently these inclusions have the form of the enclosing minerals. Small moving bubbles do not often occur. The sodalite is perfectly isotropic and very fresh. Only very locally may a corrosion and decomposition into analcite be observed, such as shown on the large sodalite grain in figure 2. Fig. 2. Sodalite-syenite. Magnified 25 diam. A hornblende, B orthoclase, © soda- lite, D analcite. A little chlorite or serpentine is sometimes infiltrated from the hornblende. The sodalite is somewhat unequally distributed through the rock; the figures are taken from places where it * Geol. Survey of Arkansas, Ann. Rep., 1890, vol. ii, p. 64. 294 Lindgren and Melville—Sodalite-Syenite is especially abundant and give a rather exaggerated idea of the quantity of this mineral. Besides the already mentioned occurrence of analcite in the: feldspar it also fills interstices between the feldspar and soda. lite grains in the manner shown in the figures. It is very clear and free from inclusions; a peculiarity of it is that con- trary to the data usually given its refraction appears stronger than that of the feldspar and sodalite. It always shows a faint double refraction in dark gray and biuish colors. and each grain usually divides into several sectors with different optical orien- tation. The form of the larger grains is triangular or poly- gonal, being molded by the crystallographic faces of the feld- spar and sodalite as shown in the figure. The interpretation of this analcite offers some difficulties. It is not derived from the sodalite ; there is no direct proof to show that it has been derived from nepheline; if it is an altered nepheline, then this mineral must have been formed later than the sodalite. No nepheline has been found so far, but it is by no means impossible that other parts of the eruptive mass might con- tain this mineral. Another possibility is that the analcite fills miarolitic cavities in the rock; it cannot then very well have been derived from any other mineral than the feldspar. The specific gravities of the sodalite and analcite were found to lie extremely close together. They both fell between 2:27 and 2°23. A special and repeated separation was made of this mixture which resulted in the two minerals being obtained in a relatively pure state. The specific gravity of the sodalite ranges from 2°27 to 2°255 while that of analcite extends from 2°26 to 224. The two products were then analyzed : III. Sodalite. IV. Analcite. EVO Gt 00s) eee 0°45 HiO(above\ 100°) s- 223-73 (CADE) SiO) Viasat say Ce 41°56 49°54 Clii2 ARR a ave 4°79 1°67 AO, Wess ya iE OO AS 25°07 ReQr. 2 eee ae ae 0°49 0°40 CaQ 202 Siac pee er 0°49 0°22 MeOn: <2 SG ee ER SOs 0-20 INO) oo eve tie 19:21 15°32 TR esata ae Sate ero 0°89 101°26 100°00 Hxcess| O} ese easy e 1:08 100°18 * By difference. and other Rocks from Montana. 295 It is evident that both of these analyses are made of mixed material and equally plain that one of the constituents is sodalite. In order to calculate approximately the composition of the two minerals let us assume an analcite composed as follows : 55S8i0, 23.A1,0,, 13°5Na,O(+K,O), 8:°5H,O = 100, and a sodalite containing 37:5 per cent SiO,. From the silica contents it follows then that (III) contains 76 per cent soda- lite and 24 per cent analcite. Calculating further the remain- ing elements and disregarding for the present the small quan- tities of Fe, Ca and Mg, one obtains (37:50 SiO,), 31:50 Al,O,, 22-20 Na,O(+K,O), 6-30 Cl, 2:20 H,O which, excepting the high percentage of water, is a normal sodalite. On the other hand, assuming a sodalite composed as above and an analcite containing 55 per cent SiO,, it follows that (IV) contains 68 per cent analcite and 32 per cent sodalite, and that the other constituents of the analcite are (55Si0,), 22-04 Al,O,, 13-40 Na,O(+K,O), 9°37 H,O = 99°81, which corresponds very closely to a normal analcite. It does not seem possible to avoid the conclusion that a part of the water belongs to the sodalite. Under the microscope the sodalite appears perfectly pure and isotropic and no other zeolites such as natrolite or hydronephelite are present. If all the water belonged to the analcite it would have to contain about 15 per cent H,O. The amount of H,O in analcite is, however, very constant and varies only between 8 and 9 per cent. Asa matter of fact, the majority of sodalite analyses do contain a small amount of water, and it has been suggested that a certain quantity of Cl may be replaced by (OH). A quantitative separation of the rock was made and the following figures obtained for which only an approximate cor- rectness is claimed : 66 feldspar. 23 hornblende. 8 sodalite. 3 analcite. 100 The proportion between albite and orthoclase could not be correctly ascertained on account of their very intimate inter- growth, but from the thin sections and from the separation it was estimated that the rock might contain 50 per cent ortho- 296 Lindgren and Melville—Sodalite-Syenite clase and 16 per cent albite. If it is further assumed, for the purposes of a calculation of the rock analysis, that the compo- sition of the two minerals is Orthoclase. Albite. Rok O ete eee Bees 68 66 NGO sae ess il 19 IN Oe pee a oe ee 11 138 Ke ie eh a ae eee ue 2 100 100 the composition of the rock may be calculated as follows: Horn- Ortho- Soda- Anal- Calc. acne blende. clase. Albite. lite. cite. comp. NGS Difference. AYA TE OR? ooh yal ay ete eae pet ne dt 0:26 rthnst ees H.Ot 0°06 Sere Sees 0-716 0°29 0°51 1-51 + 1:00 3°49 SiO. 8°83 33°00 10°88 3°00 1°65 57°36 56°45 —'9l1 55°76 IBADS ase Sete seen eee Lae wee 0-13 cs eae SASS Cl aS, a ae aoe 0°48 Ee 0°48 0°43 —'05 ee ss TiO. 0°28 Sens mene x Pye ek 0:28 0°29 Age ria Py AleOs 321 9°50 3°36 2°52 0°66 19°81 20°08 +°27 21°61 Fe,0; 0°86 on dys eee a eee Lede tee 0°86 MeSH: +745 - 1°65 FeO 5-00 pig irae pane wae 5:00 4°39 — 61 4:09 IN OR ee i cals See Epis eee nore trace ueIAG sae MnO 0:04 Se Ts an Se eS oi aes 0°04 0:09 +:05 pitied CaO 2°43 Set Bot hy dns Le 2°43 2°14 —"29 2°26 MgO 0°58 oe ee a Simos ee Sx 0°58 0°63 +°05 0-74 Na,O 0°69 1:00 1:76 1-72 0°40 Dov 5°61 +04 6°94 K.O 0°46 6°50 peas 0-08 0°03 7:07 ork +06 5°34 23°00 50°00 16:00 7:96 3°03 99°99 100°45 101 88 Excess O. 10 100°35 The complete analysis of the rock is inserted under V in the third column from the right. The analysis agrees fairly well with the calculated composition in all except SiO, and H,O; the former is very uncertain on account of no complete analysis having been made of the feldspars; the latter is too low in the calculated composition and the rock evidently con- tains more analcite than 8 per cent. s 4 = a GEO. L. ENGLISH & CO’S ANNOUNCEMENTS. A FEW RECENT ADDITIONS. FROM ENGLAND: 200 small, bright green Fluors at 10c. to 50c. 50 medium and large Fluors, green, blue, purple, 75c. to $7.50. 75 small Egr emont Twin Calcites, VERY CHOICE, clear, brilliant, beautiful, 50c. to $2.50. Sure to please anyone. 100 sparkling Specular Iron and Quartz, 2c. to $1.90. 120 Barites, various rich colors, 25c. to $1.50. 14 Yellow sheaf Barites (new), 50c. to $3.50. 75 brilliant black Blendes on Dolomite or Quartz, 25c. to $7.50, 20 fine Kidney ore, 50c. to $2.00. FROM SWITZERLAND: Rose, octahedral *Fluors, a number of unusually good crystals, 25c. to $25.00. Twisted Smoky Quartz, rare and remarkable, $1.00 to $3.00, one VERY FINE group, $20.00: FROM ALGERIA: 100 twin crystals of Pyrite, small but excellent, 5c. and 10c. each. FROM ARIZONA: ' 184 Azurite ‘‘ balls” and isolated crystals, choice, 10c. to $1.50. Polished Malachite specimens, 25c. to $1.50. Chalcotrichite, choice, 50c. to $5.00. FROM CALIFORNIA: Three tons of specimens of Rubellite in Lepidolite, very beautiful. Cabinet sizes 25c. to $2.00. Large Museum specimens, $9.00. to $50.00. - FROM UTAH: Mammoth Crystals of Selenite, one 40 inches long (!); others 8 inches and upwards. FROM COLORADO: Zircon crystals, rare forms and very gemmy, $1.00 to $2.00. Bastneesite, a few good crystals. FROM S. DAKOTA: Autunite, large and fine specimens, $1.00 to $2.50. FROM MONTANA: Gem Crystals of Sapphire, 50c. to re 00 each. FROM IOWA: Geodes full of long Millerite needles, $2.00 each. FROM MEXICO: Beautiful light and dark Amethysts, large and small, 25c. to $2.00. Apophyllite, Valencianite, Calcite, Dolomite. GEM DEPARTMENT. Recent Additions; Fine Olivines; Brazilian Topaz; Blue Spinels ; Yellow Sapphires ; Large Garnets ; Chrysober yls. LAPIDARY DEPARTMENT. Only highest grade of work done. Sapphire cutting a specialty. 100 pp. Ulustrated Catalogue, 15c.; Supplement 2 ““ Winter Bulle- tin” and other Circulars, Free. GEO. L. ENGLISH & CO., Mineralogists, 64 EAST 12TH ST., NEW YORK. CONTENTS. Art, XXXI.—Distance of the Stars by Doppler’s Prue le; by Goo W 2C OL uns, JR ae ic. re XX XII.—Double Hades of Tellurium Chik Potassium, ia bidium and Cesium; by H. L. Wuxxrrer XXXTT—Tunegstous es new Oxide of Tungsten— associated with Columbous Oxide; by W. P. Happen 280 by w. lecuvenen. with nly ees ti W. H. Mr.vitie._ 2 XXXV.—A Basic Dike near Hamburg, Sussex Co., New| Jersey, which has been thought to contain Leucite ; py Joa Sa ee 298 XXXVI.—Underthrust Folds and Faults; by E. A. Surrn_ 305 ~XXXVIi.—The Cretaceous Formations of Mexico and their — Relations to North American Geographic Development ; zi by eT. Aint oS eS ee eee ee a XXXVIT.—Electrical Oscillations of Low Browse and | their Resonance; by: M:.J_- Purin_ 22.2 22 ee KX KIX. ER cteruneanbe of Iodine in Haloid Salts by the Action of Arsenic Acid; by F. A. Goocu and P. E. DROWNING 2S oe e a TS es Soe ee ae Besa XL.— Radiation and Absorption of Heat by Leaves; ae Ge MAY BR os oe) een Molecular Masses, SAKURAI, 346.—Color of ie Tons, ORETAED: 347,— A fiinity- coefficients of Acids, LELLMANN and SCHLIEMANN, 348. —_Reaclion of Hydrogen with Chlorine and Oxygen, HARKER: Daily vatiation of Gravity, MASGART, 349.—Simple apparatus for the determination of the Mechanical Equivalent Heat, C. CHRISTIANSEN: Asymmetry in Concave Gratings, J. R. RyDBER Potential of Electric Charges, A. HEYDNEILER: Sensitive Galvanometer, H. BH. J. G. DuBors and H. RuBens: Hepa with Currents of High Frequency, A. A. C. Swinton, 350. Geology—OCorrelation Papers, Neocene (Bulletin of the U.S. Geol. Sueveue H. Dawu and G. D. Harris, 351.—Michigan Geological Survey for 1891 Geological Survey of Missouri, 1892: Geological Survey of Texas, 1892: j Journal of Geology, 354. —Republication of Coes Works: Lines of ee eure in af OUTS) 355. Tafeees of “Lah on vegetation, EK. GATN, 356. Astr onomy—Transactions of the Astr. Observatory of Yale University, 357 ey einer’s aes os a Gestirne, a Tables, G. W. jones 362. Obituary—NicoLas KOKSHAROY, 362. Chas. D. Walcott, se Geol. Survey. AMBRICAN JOURNAL OF SULEN GE, EDITORS JAMES D. anp ED WAnD pe DANA: ASSOCIATE EDITORS ; Paornssons JOSIAH P. COOKE, GEORGE L. GOODALE AND JOHN TROWBRIDGE, OF CAMBRIDGE, .: H. A. NEWTON anp A. E. VERRILL, OF pe New Haven, 2 isso GEORGE ie BARKER, OF PHILADELPHIA. THIRD SERIES. VOL. _ XLV [WHOLE NUMBER, ox No. 269. _MAY, 1893. - NEW HAVEN, CONN: J. D. & E. 8. DANA. | eee _ TUTTLE, MOREHOUSE & TEXLOR, PRINTERS, 371 STATE STREET. ublighed monthly. ‘Six dollars per year (postage prepaid). $6.40 to 2 sub- ers of countries in the Postal Union. Remittances should be made either by LETS oe see or bank checks. Bbbstned in exchange from the Riksmusem at Stockholm through B Nordenschiold, the celebrated Arctic explorer. This i is, as the Professo self last summer in many species. The following are a few. Well crystallized Columbite, 75c. to $5, 00. ao Hedenbergite, fine groups of crystals, $1.50 to $10.00. Fluocerite, $1.00 to $1.50. Gadolinite crystals, $1.00 to $5.00. a Sa) Thorite crystals, 5c. to $5.00. The largest crystal I have ever seen for sale, quite good form, weighs 12 oz. * $25.00. is Cobaltite crystals, some on gangue, 5c. to $5.00. Glaucodot crystals, some on gangue, 75c. to $7.50. eee Epistilbite, Pyrochroite, Pargasite, Ganomalite, Homilite, Malacone, ; Melinophane, Endialite, Paisbergite, Pyrosmalite, Euxenite, Native | Lead, Manganosite and hundreds of others. 5 me os CATALOGUES. | _ Minerals and Mineralogical Books. 128 pages, illustrated, free to all intend- ie: ing purchasers who request it on headed paper; to others, 5 cents. Heavy | paper edition, 10 cents. 5 Botanical, Chee Geological, Paysca Electrical and other Scien- tific Books and Papers. 32 pp. each, free, or heavy paper, 5 cents. Medical, 200 pp., 5 cents, heavy paper, 25 cents. a EXTRA RARE AND VALUABLE BOOKS. _ The following are among those received the past month. The first seven are the rare Wilkes Exploring Expedition Reports. Dana, J. D. Crustacea. 2 vols. and atlas. 96 plates, (45 a Dana, J.D. Geology. Vol. and atlas. 21 plates........... _--..- Gray, A. Phanerogamia. Vol. and atlas. 100 plates..___-_-_..__- 5 Brackenridge. Filices. Vol. and atlas. 46 plates...-.------__---- 50.00 Hale. Ethnography and Philology_------__-_---------.- ese : Pickemnso. Races: of .Men2is.2 °2s sor epee Sees Oe 3 Pickering. Geogr. Distribution of Plants and: Aninfils 2—-~ "= o-s as Agassiz. Poissons d’Eau douce del’ Europe Centrale. 2 vols. 52 fine plates, many elaborately colored, and heightened with silver, American Naturalist. First 19 vols. half roan»__..__-------------- : Wrurtz.; Dictionnaire de*Chimie:2_.-2 222 a eee Harris. Aurelian or Nat. History-of English Insects. ine colored splatessce 1194 Sa eee ee ehote sss ARGS REMOVED To 1224-26-28 North Forty frst Street, Padi THE AMERICAN JOURNAL OF SCIENCE [THIRD SERIES.] tOe Art. XLI.—On the Deportment of Charcoal with the Halo- gens, Nitrogen, Sulphur, and Oxygen ; by W. G. MIxtTErR. Charcoal containing the Halogens. THE difficulty in obtaining amorphous carbon fairly pure is a serious obstacle in an investigation of its properties. Kirwan* observed in the year 1785 that charcoal after prolonged and intense ignition contains hydrogen. The recent handbooks and dictionaries of chemistry state that the hydrogen may be removed by heating the charcoal in chlorine, while the older dictionaries contain nothing on the subject. The writer has been unable to learn who is the author of the method or to- find any mention of analytical tests for chlorine in charcoal purified by ignition in chlorine. Berthelot and Petit+ treated wood charcoal with hydrofluoric and hydrochloric acids, next with chlorine at a red heat, and finally calcined it in a Perrot furnace. Their charcoal was doubtless free from chlorine. Weber{ for his work on the specific heat of carbon prepared amorphous carbon by heating wood charcoal to bright redness for fifteen minutes in a stream of chlorine in order to remove hydrogen. It would be interesting to know that the distin- guished experimenter proved the absence of chlorine in the charcoal he used. Wright and Luff§ heated sugar charcoal for two hours in chlorine and then ignited it for six hours in platinum over a blowpipe to remove chlorine. Their analyses of two preparations are as follows: * Kopp, Geschichte der Chemie, iii, 289. + Bulletin, 1889, ii, 90. ¢ Phil. Mag, IV, xlix, 161, 276. § Jour. Chem. Soc., xxxiii, 17. Am. Jour. Sci1.—THIRD SERIES, Vou. XLV, No. 269.—May, 1893. 26 364 W. G. Mixter—Deportment of Charcoal with Garbon! e322 oo sen ee 96°17 95°13 Hydrogen =2.52-esee—- 0°84 0°75 Ash PEPE erty ee Ny amp aE Sayeed 1°56 1°68 Oxygen by difference. - 1°43 2°44 These results are interesting as ae show how tenaciously charcoal retains hydrogen even after ignition in chlorine. While attempting to prepare for use in an investigation amorphous carbon free from hydrogen the writer observed that charcoal retains considerable chlorine at high tempera- tures. This fact has doubtless been observed but there appears to be nothing on the subject in the literature of chemistry except the statement by Schénbein* that charcoal absorbs chlorine and retains some of it when heated. Experiments were made with amorphous carbon from vari- ous sources, but only the results will be given that were ob- tained with three varieties, viz: sugar charcoal, lampblack, which is finely divided charcoal, and gas carbon. The first was prepared by charring in an open platinum dish cane sugar which was almost free from ash. The charceal was pulverized in an agate mortar, moistened with sugar syrup and then pressed in a hy draulic press. The pieces were next heated to redness and plunged into a thick syrup, and this treatment was repeated until the charcoal would sink in water without boil- ing to expel the air from the still porous coal. Finally, the sugar charcoal was heated intensely for several hours in a eruci- ble by a charcoal fire in a wind furnace having a strong draught. The method employed for estimating hydrogen was as follows: the charcoal was heated to redness in a platinum tray, allowed to cool in a desiccator, then weighed and placed in the combustion tube and then, in order to drive off ab- sorbed water, it was heated to faint redness for half an hour in a current of dry air in which it did not ignite. The com- bustion was made in oxygen dried by oil of vitriol, solid caustic potash, and finally, calcium chloride. An ordinary calcium chloride tube was used to absorb the water of the combustion. In a blank test of the apparatus the calcium chloride tube gained 0:2 milligram. One lot of sugar char- coal prepared as deseribed yielded 0:13 per cent of hydrogen, 1:12 gram being used for the combustion. 1:25 gram of an- other preparation gave 0:126 per cent of hydrogen and 0:04 per cent of ash. The sugar charcoal burned with difficulty in oxygen, was hard enough to scratch glass, and was a good con- ductor of electricity. The lampblack used was of a kind made from natural gas known as “ Diamond Black.” It is well described by Mallet.+ * Poge. Ann., lxxiii, 326. + Chem. News, xxxvili, 94. the Halogens, Nitrogen, Sulphur and Oxygen. 365 My analysis of the lampblack gave 1 per cent of hydrogen, 0-04 of ash and in an air-dry portion 0°23 per cent of nitrogen by the absolute method. After igniting for two hours in dry nitrogen and allowing to cool in the gas, no nitrogen was ob- tained on burning with oxide of copper. This kind of lamp- black when pressed into compact pieces conducts electricity, and when heated zm vacuo it yields a small sublimate as ob- served by Mallet. The gas carbon used was from the inner portion of a thick piece. A combustion of 1:742 gram of it yielded 0-035 per cent of hydrogen and 0°88 of ash. The chlorine used in the. experiments was made from salt, manganese dioxide and sulphuric acid, and was passed through one wash-bottle containing water and one containing oil of vitriol. The temperature in the experiments was the highest attainable in a gas combustion-furnace, that is, a bright red heat. A hard glass or porcelain tube was used to hold the charcoal during the ignition in chlorine. Experiment 1.—10 grams of sugar charcoal were ignited in chlorine for three hours, then left for a day over solid caustic potash, and finally heated to redness for an hour én vacuo. The product weighed 10-304 grams and contained 3°7 per cent of chlorine.* Another portion of 10 grams of the same charcoal was exposed at common temperature to a current of chlorine for three hours, then dry air was passed through the tube for 15 minutes. The gain in weight of the charcoal was 0-098 gram which was not diminished by exhausting the tube and then opening to the air. The results show that cold dense sugar charcoal takes up much less chlorine than when heated. Probably chlorine is simply occluded by cold charcoal; whether chlorine is chem- ically combined which is retained by hot charcoal will be dis- cussed after the experimental results are given. Expgriment 2.—Sugar charcoal was heated to redness in a porcelain tube, then chlorine was passed through the tube for three hours, and while red hot the chlorine gas was displaced by nitrogen. The charcoal as it came from the warm tube gave off no chlorine, of which it was found to contain 4°6 per cent. Lixperiment 3.—(a) Chlorine was passed for two hours over cold lampblack, and then (6) over glowing lampblack. Both preparations of chlorinated lampblack were left for a day over solid potash in a partial vacuum. 7:9 per cent of chlorine * The estimation was made by burning the chlorinated charcoal in moist oxygen and passing the products of combustion through dilute ammonia to absorb the chlorine, which was afterwards precipitated as silver chloride by the addition of silver nitrate and nitric acid It was found that chlorinated charcoal or lamp- black burned with difficulty and often incompletely in dry oxygen. 366 W. G. Miaxter—Deportment of Charcoal with was found in first. The preparation 6 gave 14:3 per cent of chlorine by the combustion method and 15:5 per cent by fus- ing with soda and niter. The low result by the method of combustion is due to the formation of carbon chlorides which form a slight sublimate and sometimes oily drops on the am- monia water. 3°75 grams of the chlorinated lampblack of 6} were placed in a glass tube, the anterior end of which con- tained lumps of caustic potash, and the air was exhausted by a Sprengel pump. The part of the tube containing the lamp- black was heated to redness for two hours while the exhaustion was maintained by constant pumping. The evolution of gas not absorbed by potash was slow and 22° were obtained. The gas had a slight odor and burned with a blue flame. The lampblack after heating 7 vacuo contained 8°5 per cent of chlorine. Haperiment 4.—Lampblack in compact pieces* was heated in a current of chlorine for four hours in a porcelain tube to the highest temperature of a gas combustion furnace. The product after standing a day in the air contained 11-9 per cent of chlorine. 10 grams of the chlorinated lampblack were next placed in a porcelain tube which was connected with a tube containing calcium chloride and slaked lime to absorb water, chlorine and carbon dioxide. The air in the tube was pumped out so completely that after nine hours no more air was obtained by further pumping. The tube was then heated to bright redness for three hours while the Sprengel pump was in constant action. 380° of a gas were obtained which had a slight odor and burned with a blue flame. The chlorinated lampblack after ignition 7 vacuo contained 9:04 per cent of chlorine. Experiment 7.—The lampblack of the preceding experiment with 9°04 per cent of chlorine was placed in a porcelain tube plugged with asbestos, and the sugar charcoal of experiment 2 containing +4°6 per cent of chlorine was put into a eovered porcelain crucible. Both were heated in a covered clay eru- cible in a coal fire for fifteen hours, much of the time to a white heat. The porcelain was softened. No chlorine was detected in either carbon after the ignition. The test was made by cau- tiously heating the carbon with soda to which niter was gradually added and then testing for chlorine by the usual method. The ash of the sugar charcoal increased from 0-04 to 0-17 per cent, due undoubtedly to the absorption of vapors, * The lampblack was obtained in compact form by subjecting it to a pressure of about 2500 pounds to the square inch in a hydraulic press. Pressed Jamp- black is one of the best forms of charcoal for many kinds of experiments as it is uniformly porous and consists of very minute particles. That used in the experi- ments sank slowly in water, that is, its apparent density was 1 while the true density was according to Mallet 1:7. the Halogens, Nitrogen, Sulphur and Oxygen. 36 perhaps chlorides, during the intense ignition. The following is the analysis of dechlorinated sugar charcoal for hydrogen : 14964 grams of the carbon which had been heated to dull red- ness and cooled in a desiccator were placed in a combustion tube and then heated again to dull redness while a slow current of dry air was passing through the tube to expel if possible all water. The carbon did not appear to burn. The chloride of calcium tube was then attached and the combination made with oxygen. 0:073 per cent of hydrogen was obtained. Another determination with 1-089 gram not heated until placed in the combustion tube gave 0-065 per cent. Experiment 8.—Gas carbon in lumps was ignited in chlorine and then was allowed to cool ina current of dry nitrogen. Two tests failed to reveal any chlorine in the gas carbon thus treated. Finely pulverized gas carbon was also found to take up no chlorine at a red heat. As gas carbon does not combine with chlorine the question was suggested: Will charcoal from which chlorine has been expelled by heat take up chlorine again? The following results show that it will. Experiment 9.— The dechlorinated sugar chareoal of 7 was found i peony 3°24 per cent and the dechlorinated lampblack 2°82 per cent of chlorine after ignition in chlorine. Exper a 10.—Lampblack and sugar charcoal were ignited for two hours in dry hydrochloric acid gas, and while hot the gas was displaced by dry air. The lampblack contained a minute trace and the sugar charcoal 0-26 per cent of chlorine. Experiment 11.—Dry hydrogen was passed over the com- pact chlorinated lampblack of 4 At ordinary temperature no hydrochloric acid appeared, while at a temperature a little below redness the acid came off for three hours, and at a red heat more acid came off. A test showed that the charcoal still contained a little chlorine. Experiment 12.--Lampblack and sugar charcoal were ig- nited for two anda half hours in bromine vapor which was finally displaced from the hot tube by a current of dry air. The lampblack was found to contain 3:04 per cent of bromine, and after exposure 7m vacuo to a red heat for two hours it con- tained 1-49 per cent of bromine. The sugar charcoal absorbed only 0 25 per cent of bromine, most of which it lost on ignition Mm vacuo. Experiment 13.—TVhis experiment was conducted like the preceding, iodine being used. The lampblack contained 2-04 and the sugar charcoal 0°63 per cent of iodine, both prepa- rations retaining but a trace of iodine after ignition for three hours 7m vacuo. 368 W. G. Mixter—Deportment of Charcoal with Experiment 14.—96 grams of lampblack were chlorinated by heating for an hour in chlorine, and then allowed to cool in a current of gas. After standing for a day the product was burned in a current of dry oxygen. In the cool and narrowed part of the combustion tube a slight sublimate formed not sufficient for a quantitative analysis. It was found to con- tain chlorine and to burn with a smoky flame. The gaseous products of the combustion were passed through dilute ammonia on which a slight oily product collected. There was a little loss of chlorine in the fume which escaped from the ammonia which was found to contain, after the combustion was finished, 2°638 grams of chlorine, showing that the lamp- black had taken up 27 per cent of its weight of chlorine. Experiment 15.—Native graphite was ignited for two hours in chlorine, which was then displaced while hot by air. The graphite retained but a trace of chlorine, owing doubtless to impurities. Kxperiment 16.—Half a gram of fragments of white dia- monds remained unchanged in weight after ignition in chlorine for an hour. Chloroform, benzene, aleohoi and ether failed to dissolve anything from chlorinated lampblack. Boiling dilute ammo- nia water removed a little chlorine, but the lampblack after protracted digestion with ammonia retained chlorine. A por- tion of the chiorinated lampblack of 3 which had been heated in vacuo and contained 8% percent of chlorine was mixed intimately with artificial alumina. The mixture gave no subli- mate on heating in a glass tube in the blast lamp. The test was repeated with a new mixture and the tube containing it was heated in a combustion furnace for half an hour. No sublimate formed, but on passing chlorine over the mixture aluminum chloride appeared at once and was rapidly deposited in the cool part of the tube. Gas carbon, alumina and chlo- rine yielded at a red heat only slowly a small quantity of aluminum chloride. The foregoing experiments were made to find whether chlorine held by charcoal at high temperatures is occluded, that is condensed in the pores and on the surface or is chem- ically combined with the carbon. It is not probable that the chlorine is occluded since gases condensed by charcoal are given off im vacuo on heating. If the chlorine were occluded then we should expect that bromine and iodine would be held in larger quantity by charcoal, as the more readily condensible gases are absorbed in the largest quantity, but glowing char- coal retains less bromine than chlorine and still less iodine. Charcoal facilitates combination of gases but when hydrogen the Halogens, Nitrogen, Sulphur and Oxygen. 369 is passed over hot chlorinated charcoal hydrochlorie acid, which is not retained by hot charcoal, is formed very slowly. Assum- ing that chlorine combines chemically with glowing charcoal, the question is, Does the chlorine unite directly with the earbon? Berzelius* stated, ‘“ In wasserfrei Chlorgas wird ein wohlausgeglihte Kohle bei keine Temperatur verandert.” Nothing was said about testing the charcoal for chlorine. Recent writers state that carbon and chlorine do not unite directly, and the foregoing results with the diamond, graphite and gas car- bon are in accord with this view. Chlorine, however, combines at high temperatures with charcoal which is not pure carbon but contains hydrogen and the latter is apparently replaced by chlorine in the chlorination of charcoal. Gas carbon contain- ing 0:035 per cent of hydrogen does not take up chlorine, while sugar charcoal with 0-07 per cent of hydrogen does. Further experiments are necessary in order to determine whether sugar charcoal and gas carbon with a like content of hydrogen differ in their deportment towards chlorine. Nitrogenous Charcoal. Animal charcoal is known to contain nitrogen and to yield cyanogen to molten alkalies but the amount is not given, although doubtless known to manufacturers of animal charcoal and cyanides. It is stated on page 865 of this Journal that lampblack retains no nitrogen after ignition in dry nitrogen. This accords with the accepted fact that charcoal does not com- bine at high temperature with free nitrogen. The results of the following experiments show that charcoal not only retains nitrogen at very high temperatures when once combined with it, but also fixes it when ignited in an atmosphere of com- pounds of it such as ammonia and the oxides of nitrogen. In the decomposition of these bodies by glowing charcoal the nitrogen may be regarded as in the nascent state. The lamp- black used in the tests was the *‘ Diamond Black” variety described on page 364 of this Journal. Experiment 1—Lampblack was heated to redness for an hour and a half in dry ammonia gas, and while the tube was hot the ammonia was displaced by dry nitrogen. The product contained 3:17 per cent of nitrogen. On heating the nitrogenous lampblack for half an hour to a red heat 7m vacuo some am- monia came off owing to hygroscopic moisture, and the per- centage of nitrogen fell to 2°68 per cent. Experiment 2.—Hard-pressed lampblack was heated for an hour to the highest heat of a gas combustion furnace in a por- celain tube through which dry ammonia gas was passed. ‘The * Lehrbuch des Chemie, 1843, i, 301. 370 W. G. Mivter—Deportment of Charcoal with ammonia was displaced by dry nitrogen and the tube was exhausted. The product contaimed 2°22 per cent of nitrogen. In this and the preceding experiment considerable hydrogen was set free from the ammonia. Experiment 3 was a repetition of 2 with the difference that the ignition In ammonia was maintained two hours. The escaping gases contained cyanogen. The lampblack contained 3°18 per cent of nitrogen. Experiment 4.—Sugar charcoal, containing 0126 per cent of hydrogen and 0-04 per cent of ash, was heated to a bright red heat and dry ammonia was passed over it for an hour, and then the ammonia was displaced by nitrogen and the tube allowed to cool. The hydrogen set free was collected over water and tested by burning. The charcoal after ignition in ammonia yielded 0:16 per cent of nitrogen on combustion. A portion of it was heated with sodium carbonate until it disap- peared, the fused mass was dissolved in water and a mixture of ferrous and ferric chloride was added and the whole was warmed and then cooled. On aciditying with hydrochloric acid a small amount of prussian blue appeared. As incandescent charcoal and ammonia react to form eyano- gen it may be that the last is the compound taken up by the charcoal in the experiments with ammonia, since cyanogen reacts with charcoal producing a nitrogenous coal as shown by the following: Experiment 5.—Pressed lampbiack was placed in one end of a tube and mercuric cyanide in the other end, and the tube was gently heated while dry air was passed through it to remove moisture. Next the lampblack was heated to a red- heat which was sufficient to decompose paracyanogen, and the mercuric cyanide was gradually heated so that cyanogen gas passed for half an hour over the lampblack which was then allowed to cool in the gas. The lampblack was next heated, but not to redness, for half an hour in an exhausted tube to remove occluded cyanogen. Gas ceased to come off toward the end of the heating a vacuo. The product contained 6-48 per cent of nitrogen. It was finally heated zm vacuo for one hour to redness when it gave off but little gas and no eyanogen. After the second heating 7m vacuo the lampblack was found to contain 6-46 per cent of nitrogen. When it was ignited in steam, ammonia was formed abundantly. Experiment 6.—Animal charcoal of unknown origin but presumably from blood, as it left after burning only a small amount of red ash, was heated to redness in a covered platinum crucible, and then was found to contain 6°82 per cent of nitrogen. the Halogens, Nitrogen, Sulphur and Oxygen. 371 Experiment 7—Albumin from blood was charred in a covered platinum crucible, and the residue was exposed to the heat of a blast lamp five minutes after the escaping gases eeased to burn. The charcoal, which was very bulky and soft, contained 4:43 per cent of nitrogen. It gave off ammonia when heated in steam. A portion of the charcoal after heat- ing for three quarters of an hour to the melting point of cast iron gave a distinct reaction for nitrogen by “the test with molten sodium carbonate, ete. Lixperiment 8.— Carefully washed and dried egg albumin charred as above yielded a charcoal containing 4°61 per cent of nitrogen. In “experiments deseribed hereafter the charcoal used was not strongly heated and was made by charring sugar in a large platinum dish heated by a bunsen burner. Experiment 9.—10 grams of sugar charcoal were heated in a glass tube for a time to faint redness and then to the highest heat of a combustion furnace. During the heating 7 liters of pure nitric oxide* were passed over the al The charcoal did not glow as when burning rapidly, and about one- third of it was consumed. Carbonic oxide came off abundantly and with it small quantities of carbon dioxide, ammonia, and cyanogen. The charcoal after cooling was pulverized and then heated to incipient redness im vacuo. ‘Thus treated it contained 3°44 per cent of nitrogen, but after heating for an hour in a Perrot furnace it was free from nitrogen. ‘The com- plete removal of the nitrogen was doubtless due to the action of vapor of water from the burning of the gas. Experiment 10.—This was conducted as nearly as possible like the preceding experiment with the exception that pure nitrous oxide was used. The product contained 1:09 per cent of nitrogen. Lixperiment 11.—This was a duplicate of Exp. 10, with the difference that the charcoal was allowed to cool in dry carbon dioxide after the combustion in nitrous oxide was stopped. 5°85 per cent of nitrogen was found in the product. A part of this nitrogenous charcoal was heated for an hour to the highest temperature of a Perrot furnace. The charcoal was held in the middle of a porcelain. tube by plugs of asbestos, and lower end of the tube which was not heated contained ealcium chloride to dry the air in the tube. The charcoal after exposure to the intense heat was found by the absolute method to contain 0-46 per cent of nitrogen. The charcoal was also further tested by heating with sodium carbonate, dis- * The nitric oxide used in this and subsequent experiments was made from nitric acid by means of ferrous sulphate and was dried by sulphuric acid. 372 W. G. Mixter—Deportment of Charcoal with solving the saline mass in water and then adding successively a solution of ferrous-ferric chloride and hydrochlorie acid. The prussian blue reaction showed the presence of more than a trace of nitrogen. Experiment 12.—17 liters of nitric oxide were passed dur- ing an hour and a half through a tube containing 20 grams of charcoal heated to a dull red. 8 grams of charcoal were burned. The charcoal in the posterior end of the tube glowed feebly and mostly disappeared and the small portion remain- ing unburned contained 15°33 per cent of nitrogen, while the charcoal in the anterior end contained only 096 per cent. 0-092 gram of ammonia was obtained by passing the gases of the combustion through hydrochloric acid. Experiment 13.—This was made as nearly as possible like the preceding, nitrous oxide being used. The charcoal burned more rapidly than in nitric oxide and with a yellow flame, dis- appearing completely in the posterior end of the tube. When, however, the heat was lowered to a faint red a small portion of unburned charcoal next the current of gas remained which con- tained 3°39 per cent of nitrogen, the charcoal from the anterior end yielding 0-26 per cent. The total amount of ammonia col- lected in the gaseous products of the combustion was 4 milli- grams. When the nitrogenous charcoal of this experiment. was heated in steam ammonia was formed. Experiment 14.—30 grams of charcoal were kept at a dull red heat for three hours while 50 liters of nitric oxide were passed over it. The gas was dried by sulphuric acid in three wash bottles. The small portion of chareoal which remained in the posterior end of the tube contained 13°79 per cent of nitrogen. ‘lhe nitrogen was not estimated in the remainder of the coal which was found to yield cyanogen to a hot con- centrated solution of potassium hydroxide. The charcoal used in the foregoing experiments contained considerable hydrogen and oxygen, when, however, charcoal nearly free from hydrogen is partly burned in nitric oxide no nitrogen is retained as the following shows: Experiment 15.— Charcoal containing 0126 per cent of hydrogen and no nitrogen was used. 10°5 grams of dense pieces were heated in a tube from which the air was displaced by dry carbon dioxide. 17 liters of nitric oxide dried by sul- phurie acid in three bottles were passed over it in 85 minutes and the highest temperature of a combustion furnace was maintained. 38-7 grams of the coal were burned, the piece in the posterior end of the tube falling to a powder, which was found by the following test to contain no nitrogen: 0°2647 gram of the charcoal and 1°3 gram of potassium chlorate inti- a the Halogens, Nitrogen, Sulphur and Oxygen. 373 mately mixed with freshly ignited copper oxide were placed in a combustion tube, and then copper oxide, a long roll of bright copper gauze and hydrogen sodium carbonate were put in. The tube was exhausted by a mercury pump and the combus- tion was made as usual in the absolute method. 0:2° of gas was collected, the amount repeatedly obtained in blank tests. This method was employed in all the estimations of nitrogen in ebarcoal, experience having shown that it is difficult to burn charcoal with copper oxide alone, and that it is better to mix the coal with 5 parts of chlorate than to place the latter in the end of the tube. In none of the determinations of nitrogen was the copper gauze perceptibly oxidized. Experiment 16.—Uric acid was heated in a covered platinum crucible over a large gas burner as long as combustible gases came off. The resulting charcoal contained 34:06 per cent of nitrogen. Experiment 17.—Uric acid was charred by heating gradually at first, then for half an hour to the highest temperature of a Perrot furnace. The charcoal after this intense ignition yielded 3°52 per cent of nitrogen. Experiment 18.—Urie acid contained in a covered platinum crucible was heated gradually and the charcoal formed was kept at a dull ret heat for 15 minutes after the escaping gases ceased to burn. This product had 89°62 per cent of nitrogen. It was an exceedingly bulky black powder which gave off ammonium cyanide when heated in a current of dry hydrogen. Experiment 19.—1 gram of paracyanogen left 6 milligrams of black residue after heating for two minutes in a covered platinum crucible over the same lamp that was used in 76. Nitrogenous charcoal which has been intensely heated does not contain paracyanogen as this is converted into gaseous cyanogen by heat. It is possible that the charcoal from uric acid with the large content of nitrogen is composed in part of paracyanogen. Charcoal containing Sulphur. Berzelius* made the following statement regarding a solid sulphide of carbon: “ Die Kohle, welche zur Darstellung dieser Verbindung (carbon disulphide) angewandt worden ist, enthilt Schwefel in chemischer Verbindung, der nicht durch Gliihen ausgetrieben werden kann, wenn dabei der Zutritt der Luft verhindert wird.” This fact, not mentioned in recent works on chemistry, must be familiar to manufacturers of carbon disul- * Lehrbuch der Chemie, 1843, i, 300. 374 W. G. Mixter—Deportment of Charcoal with phide. Solid compounds of carbon and sulphur formulated as CS.C,S,, and C,S, have, however, been deseribed. Experiment 1.—30°9 grams of air dry soft sugar charcoal were kept at the highest temperature of a combustion furnace for an hour and a half, and during this time the vapor of 30 grams of sulphur was brought into contact with it. No sul- phur passed unchanged over the charcoal but hydrogen sul- phide came off abundantly during the first half of the time of heating. When all the sulphur had been distilled from the end of the tube containing it dry hydrogen was passed in and hydrogen sulphide was again formed. The charcoal after cool- ing in a current of hydrogen weighed 30°1 grams and con- tained according to two estimations 20:02 and 19°95 per cent - of sulphur. The sulphurized charcoal gave up no sulphur when treated for five minutes with a boiling solution of potas- sium hydroxide having a density of 15. The charcoal sank in the solution and hence had a density higher than 15. A portion of the charcoal gave off at the heat of a combustion furnace a little hydrogen sulphide and sulphur but no carbon disulphide, while another portion gave off the last at a bright red heat in a Perrot furnace. A third portion of the sul- phurized charcoal was placed in a porcelain crucible surrounded by sugar charcoal in a clay crucible and was heated to the highest temperature of a Perrot furnace which melted east iron readily. The charcoal after the intense ignition retained 3-4 per cent of sulphur. It was free from ash and, when burned in a current of moist oxygen in a combustion furnace, left a small amorphous black coal which disappeared when the tray holding it was heated over a blast lamp. Lixperiment 2.—Vapor of carbon disulphide was passed for an hour over soft sugar charcoal at a red heat. The carbon disulphide was displaced by dry hydrogen in which the char- coal was allowed to cool. Hydrogen sulphide was formed abundantly at first, while during the latter part of the time of heating but little was detected. The charcoal sulphurized by carbon disulphide was found to contain 11°14 per cent of sul- ohur. Experiment 3.—1:2632 gram of sugar charcoal containing 0126 per cent of hydrogen and 0:04 per cent of ash was exposed for twenty minutes to sulphur vapor at the highest heat of a gas combustion furnace and then was allowed to cool in a current of dry hydrogen. The charcoal lost 0:0055 gram in weight and was found to be free from sulphur. Experiment 4.—Charcoal such as used in the preceding test was subjected to sulphur vapor at the temperature of a Perrot furnace. It was next heated to redness in a crucible to drive the Halogens, Nitrogen, Sulphur and Oxygen. B15 off occluded sulphur and was then found to contain 0°29 per cent of sulphur. Carbon disulphide was not produced in this experiment nor was it likely to be formed since the tempera- ture of the furnace was sufficient to decompose it as was proved experimentally. Fxperiment 5.— Filter paper nearly free from ash was charred at a dull red heat in vapor of sulphur and the latter was displaced by hydrogen. The product contained 29-1 per cent of sulphur. Experiment 6.—Filter paper in loose rolls was placed in a large glass tube and was then wet with a saturated solution of sulphur in carbon disulphide. The latter was driven off and a considerable quantity of solution of sulphur was poured into the tube. After the carbon disulphide was expelled from the tube again the paper was charred by gradually heating to incipient redness, and dry hydrogen was passed through the tube during the heating and cooling. Two estimations of sul- phur in the charcoal gave 46-46 and 46-60 per cent. This sulphurized charcoal yielded nothing to boiling carbon disul- phide and gave up no sulphur to a boiling solution of potas- sium hydroxide. Lixperiment 7.—This was made as nearly as possible like the preceding. The product contained 43°64 per cent of sulphur and exhibited the same negative deportment towards carbon disulphide and potassium hydroxide. The results show that nearly pure amorphous carbon takes up but little sulphur, while a soft charcoal containing much hydrogen and oxygen takes up considerable even from carbon disulphide. The sulphur is chemically combined as Berzelius held, for it is not removed by solvents even from charcoal which is nearly one half sulphur. Combustion of Charcoal in Oxygen. The paper by H. B. Baker* on combustion in dry oxygen suggested a lecture experiment to show that charcoal will not burn in dry oxygen as readily as it does in the gas containing water. Tor this purpose Hoffman’s experiment} was modified by allowing the oxygen in the apparatus shown in fig. 1, to dry for a day or longer by contact with phosphorous pentoxide contained in a short tube just below the bulb. The charcoal was hung on the small wire above the spoon and was intensely heated, cooled in carbon dioxide and then placed in the ap- paratus. To carry out the experiment the wire was heated by electricity until the charcoal was glowing at the point of con- * Jour. Chem. Soc., xlvii, 349. + Berichte der deutsch. chem. Gesellsch., ii, 251. 376 W. G. Mixter—Deportment of Charcoal with tact with the wire. In many of the trials the charcoal ceased to glow as soon as the current of electricity was stopped, burning readily, however, when ignited in moist oxygen. The failures in the experiments led to an investigation of the burning of charcoal. Baker* in his experiment used charcoal previously ignited in chlorine. Such charcoal contains chlorine unless heated for a long time to a white heat,+ and the writer has frequently observed that chlorinated charcoal only partly burns at the temperature of a combustion furnace in oxygen dried as for organic analyses, and that after the coal has ceased to glow it ignites again on admitting. moist oxygen and burns completely. Dubrunfautt failed to burn sugar charcoal mixed with copper oxide ina current of dry oxygen. Other chemists have alluded to the difticulty attending combustions in dry oxygen; Dumas,$ however burned graphite in oxygen dried by solid caustic potash and sulphuric acid. A Hoffmann apparatus, such as shown in fig. 1, was used in the investigation. It held about 350° of gas and had heavy platinum wires passing through the stopper to the small wire which held the charcoal. To prepare it for use sufficient mer- cury was poured in to fill the tube at the bend below the stop- cock and a short wide tube containing phosphorous pentoxide was placed in the neck below the bulb which was then closed. Next the charcoal and all the platinum below the stopper were heated ina blast lamp. The charcoal used in J, 2, 3 and 4, was allowed to cool in carbon dioxide, but the sugar charcoal of the other experiments was put into the apparatus while glowing as it did not burn in air. The apparatus was then filled with oxygen by passing through it about two liters of the gas dried as for organic analyses. In 7, 2, 3 and 4, the sup- porting wire passed through a hole in the charcoal, thus giving only one point of contact, in the other experiments it was placed in an inverted cone of platinum wire. Experiment 1.—0:033 gram of dense wood charcoal pre- viously heated to redness tor an hour was taken, and the gas was allowed to dry a day. The charcoal ignited when heated by a current of electricity through the wire and burned com- pletely without further heating. The volume of the gas at * Loe. cit. + This Journal, p. 364. ¢ Comp. rend., Ixxiii, 1395. § Comp. rend., xxiv, 137. “-_ee the Halogens, Nitrogen, Sulphur and Oxygen. B77 the temperature of the room, which was constant, was 18° greater than before the combustion. Fixperiment 2.—0-0337 gram of same charcoal as used in 7, gave the same results, except that the volume of gas increased 2°45, Exeperiment 3.—Another lot of hard burned charcoal was tried in gas dried fora day. Three times the coal failed to burn after it had been heated at one point to ineandescence, burning, however, brilliantly when ignited by prolonged heating. Experiment 4.—The charcoal from the same piece as used in 3, did not burn when first heated to redness at one point but when heated a second time it burned well. Experiment 5.—Dense sugar charcoal containing 0'126 per cent of hydrogen ignited promptly when the wire cone hold- ing it was heated, and burned brilliantly and completely in oxygen which had been in contact with phosphorus pentoxide thirteen days. For the remaining experiments with the Hoffmann appara- tus the sugar charcoal described on page 366 was used. It contained 0:07 per cent of hydrogen and 0-17 per cent of ash. The amount weighed off for each trial was 0°04 gram, which was somewhat reduced by heating as already described. The gas was allowed to dry for two days in each case. Experiment 6.—The charcoal did not burn after it was heated to faint redness, but when heated hotter it continued to burn after the current from the battery was broken. The volume of the gas increased 1:°5°. Experiment 7.—The charcoal after it was first ignited burned a few seconds. Ignited a second time it partly burned, and it did not burn completely until it was heated intensely. The volume of the gas was 2° greater than before the combustion. Hixperiment 8.—The charcoal burned completely after the battery current was broken. In this and the following tests the apparatus stood in a cylinder of water having the tempera- ture of the room. ‘lhe pressure of the gas when it had at- tained the temperature of the water was 2°4™™" of mercury greater than before the combustion. Experiment 9.—The result was the same as in 8, except that the pressure increased 2™™. Experiment 10.—The charcoal was heated gradually until it was ignited. .The pressure increased 3™™. Lixperiment 11 —The charcoal ceased to burn after the first heating by the hot wire and when ignited again it burned com- pletely. The pressure increased 2™™. The increased volume of gas after a combustion can only be explained on the assumption that some carbonic oxide was 378 W. G. Mixter— Deportment of Charcoal with formed, althongh the oxygen largely exceeded the amount required for the complete oxidation of the carbon. To prove that the increase was not due to heating the wires passing the stopper, the wires were repeatedly heated by an electric current and the gas in all cases returned on cooling to its original vol- ume. Nor could any air have passed in by the stopper for the pressure in the apparatus was greater during the combustions than that of the atmosphere. The above results throw no light on the question of the burning amorphous carbon in dry oxygen, as charcoal contain- ing 0:07 per cent of hydrogen and upwards was used, which would yield water. It is evident, however, that dense charcoal must be intensely heated before it will burn in dry oxygen. When such charcoal ceases to burn after.having been ignited at one point it may be that the temperature of the part burn- ing falls below the point of ignition owing to the dense coal conducting heat from it. Charcoal even of the densest var lety when burning rapidly in oxygen is surrounded by a small flame which may be due in part to the incandescence of carbon di- oxide and oxygen about the piece, but the flame is chiefly that of burning carbonic oxide, which formed in the reaction between the oxygen and glowing carbon, as the latter is in ex- cess in the limited space where the reaction occurs. Carbonic oxide is formed either by the direct union of oxygen with ear- bon or by the reduction of carbon dioxide. Carbonie oxide, as Meyer* has shown, burns when mixed with dry oxygen only when intensely heated by a powerful electric discharge, and carbonic oxide mixed with air or with an excess of oxygen not dried burns with difficulty and ignites only at a high tem- perature. In order then that charcoal may continue to burn in oxygen the temperature must be maintained sufficiently high to ignite the carbonic oxide. Rapid combustion will do this while slow combustion will not, as the following results show : Fixperiment 12.—A piece a centimeter thick of dense char- coal having 0:126 per cent of hydrogen was placed in a glass tube and a rapid current of oxygen was passed in, the gas being dried as for organic analysis. The charcoal was heated by one burner until it “began to glow. It then rapidly became hotter and in a few seconds there was a slight puff, flame pass- ing 20 or 30 centimeters through the tube, after which the charcoal burned brilliantly with a slight flame surrounding it. This result has been attained many times, not, however, with- out failures. Kepervment 13.—A. piece of dense wood charcoal a eenti- meter thick and three centimeters long when heated in a rapid * Berichte der deutsch. chem. Gesellsch., xix, 1099. the Halogens, Nitrogen, Sulphur and Oxygen. 379 current of moist oxygen commenced to burn without any puff. It was allowed to cool until black on the outside and the gas in the tube was replaced by air. When the oxygen was turned on again the coal began to glow and in four or five seconds there was an explosion accompanied by a distinct click, flame passing from the coal through the tube for a distance of 40 centimeters. The experiment was repeated a number of times. If the oxygen was turned on when the charcoal was incandescent on the outside there was no puff and no flame passed along the tube. A soft porous charcoal gave no pufis. i) Fixperiment 14.—The glass tube shown in fig. 2 contained charcoal at 6 which was kept hot during the experiment. At @ was a piece of dense wood charcoal a centimeter thick and three long. The two pieces were 40™ apart. Oxygen not dried was supplied through the small tube. When the char- coal at @ was first heated it took fire without any puff. The oxygen was then turned off and as soon as the coal at @ ceased to glow air was passed into the tube to displace the gas in it. On turning on the oxygen again the charcoal at @ commenced to glow and the charcoal at 6 burned brilliantly, showing that the other piece had not consumed all the oxygen. After afew seconds there was a slight explosion. The experiment was repeated many times until the piece at @ was mostly consumed. The flame accompanying the explosions usually passed from a to 6, but sometimes it passed from 6 to a. In 7/2 the amount of hydrogen and water present was very small and the explosive mixture of gases may be regarded as consisting of oxygen and carbonic oxide and possibly some earbon dioxide. When the charcoal was glowing feebly car- bonic oxide was formed and together with oxygen passed beyond the coal and when the temperature of the burning coal reached the point of ignition of carbonic oxide there was an explosion, and the coal then burned with a flame. In 13 and 74 the gas was used moist and the charcoal also yielded water when burned. But in these experiments the slow oxida- tion in presence of an excess of oxygen yielded a combustible gas that required a higher temperature than that of feebly burning charcoal to ignite it. AM. Jour. Sc1.—TairD Series, Vou. XLV, No. 269.—May, 1893. 27 380 L. V. Pirsson—WNote on some Volcanic Rocks Art. XLII.—Wote on some Volcanic Rocks from Gough's Island, South Atlantic; by L. V. Pirsson. THE rocks which are the subject of this note were gathered as beach pebbles from the shore of Gough’s Island, South Atlantic Ocean, lat. 40° 20’8., lon. 9° 44’ W_, by the eaptain of a whaling vessel from New London, Conn., and they came into possession of the writer through the kindness of Prof. C. E. Beecher of the Peabody Museum in New Haven. While in general the mere petrographical description of rocks disconnected from their geological occurrence and rela- tionships has little value or interest, the fact that nothing so far as the writer can learn has ever been published on this remote locality, and also that the material developed several points of interest are the reasons for the publication of this note. Gough’s Island was discovered in the sixteenth century by Gongalo Alvarez, and later by Gough, an English navigator, after whom it is generally called. The island seems to be little known and a search through the literature has given only the information that it is a craggy mass rising to a height of. 4850 feet and about eighteen miles around, of a generally agreeable climate, with streams which present several fine cas- cades and several valleys green with turf and bushes.* Tris- tam da Cunha, the group of islands lying 240 miles N.W., are of volcanic origin, as others of the detached oceanic islands of the South Atlantic, and from what has been given and the evidence afforded by the present investigation it is probable that the island represents a volcanic cone. The material consisted of a small number of rounded peb- bles, all of which represent very fresh voleanic rocks or tuffs which may be referred either to trachytes or basalts. Basalt. This is represented by two varieties, one of which is a rock of a dark gray color thickly dotted with black phenocrysts of augite, yellow olivines and white feldspars of the microtine habit The groundmass is dense and cannot be resolved by the eye alone. The augites are the largest phenocrysts, attain- ing at times a length of 5™"; the feldspars and olivines are much smaller. In thin section under the microscope the rock is seen to be beautifully fresh and unaltered and the usual minerals to be present, viz: iron ore, apatite, olivine, augite and plagio- *Cf. Earth and its Inhabitants; Africa, vol. iii, pp. 97. New York, 1888. Appleton & Co. Srom Gough's Island, South Atlantze. 381 clase, the last two in two generations. The augite is of a pale brownish color, non-pleochroic and shows a marked dispersion of the optic axes emerging from extinction, on one side bluish, on the other yellowish in color. In the second generation it is similar and scattered through the feldspar staves in rounded, irregular granules and often attached to iron-ore grains. The feldspar phencerysts are tabular on 7-2 (O10), and from their high extinction angles in the zone 100, 001 and on the clino- pinacoid (010) it is seen that they are to be referred to labra- dorite. On the other hand the lath-like feldspars of the groundmass are to be referred to andesite. The usual laws of twinning abound. The other minerals present nothing worthy of mention. In structure the rock is an interwoven mesh of feldspar laths in which the other minerals lie imbedded. It is rather of an andesitic habit owing to the prevalence of the feldspar but from the abundance of olivine and the basicity of the rock, a determination of silica having given 48°61 per cent, it should undoubtedly be referred to basalt. Its specific grav- ity is 2390. The second type of this rock is macroscopically of a dark grayish brown color, weathering to a brown, porous in texture and thickly dotted with white broad lath-like phenocrysts of feldspar which frequently attain a length of from 5—6™™ and often group themselves into radial starlike clusters. In thin section iron ores, apatite, olivine, augite and feldspars are dis- closed. The olivine exists in two forms, in large irregular phenocrysts attaining 1™™ in diameter and in stall crystals averaging about 05=", The larger phenocrysts are undergo- ing a process of alteration into an orange-red colored mineral. This proceeds inwardly along the edges and cracks and seems to be in two stages which are best observed under crossed nicols. The first stage seems fibrous and gives a rolling ex- tinction, until the second stage is reached where the mineral again becomes apparently homogeneous and extinguishes as such. In this product the orientation of the axes of elasticity are different from the original. In the smaller olivines men- tioned the process has been entirely completed and they all appear of this orange-red color but appear otherwise homo- geneous and extinguish parallel. A somewhat similar case is mentioned by Michel Lévy* as occurring in the basalts of Mont Dore. It is probably conditioned by a change of ferrous to ferric oxide and is somewhat like the coloration in the oli- vines in the limburgite of Sasbach.t+ * La Chaine des Puys et le Mont Dore, Bull. Geolog. Soc. France, 3d serie, xviii, 1890. + Rosenbusch, N. J., 1872, pp. 59; also Physiog. d. Min., 1892, pp. 472. 382 LI. V. Pirsson—Note on some Volcanic Rocks The augite as a phenocryst is rare but presents nothing re- markable. The feldspar phenocrysts are of labradorite as indicated by their optical properties and by their sp. g. 2°708 taken with a heavy solution and Westphal balance. There is the usual albite and pericline twinning. The growndmass con- sists of fine feldspar laths in character near andesite, the small olivines referred to and between these globulitic material, augite microlites, iron ore, glass, etc. This interstitial material is of a dark grayish brown color in which the colorless feld- spar laths lie, looking like slits in the section. A determination of silica in this rock gave 49°55 per cent and its sp. gr. is 2°648, the lowness of which is no doubt due to the glass of the groundmass. From these and the mineral com- position it is evidently to be referred to basalt. Trachyte. This is represented by trachytie tuffs and obsidian. The latter is macroscopically, a black, pitchy looking glass filled with pores which by their extension in one direction indicate flow movements in the viscous fluid. Rarely small feldspar pheno- erysts are to be seen. Before the blowpipe this glass melts readily, puffing up into a grayish pumice which then melts to glass with the utmost difficulty, a small amount of water present increasing the mobility and lowering the melting point as noted previously by other observers on acid glasses. The chemical analysis of this glass gave the following composition : NS) Oe ee PAO odor KO) Bas pe a 61°22 TUCO ages petits 42 Je O} a sages ea a 18°01 Mel OHOu ae ie 1E32 ING OMS ARLE ehigaite 4:5] Mint @ ce tee tee Se tr Mic Ona iia rer ts 44 CaQ teh eteaiie ties 1°88 IN 220) eet ee eee 6°49 Ki @Qwisees cae 5:93 TOC EG Ie ener 46 otal ts sae) sce 100°68 From the moderate amount of silica, low lime and mag- nesia and high alkalies, it is evident that this glass is to be referred to trachyte, perhaps of the phonolithoid type. In thin section it appears as a fresh unaltered glass of a deep brown color scattered through which are a few grains of iron ore, apatite crystals, an occasional sanidine or olivine pheno- From Gough's Island, South Atlantic. 383 eryst, and as the final products just before consolidation globu- lites and small sanidine microlites. The olivine oceurs very rarely indeed. It is fresh and of a pale yellow color and shows magnetic resorption. That it is indeed olivine is shown by its optical behavior, its high double and single refraction, its extinction parallel to two cleavages at about right angles, one of which is more pronounced than the other, and its general outline and habit. This was confirmed by treatment of the powdered rock by hydrofluoric acid according to Fouqueé’s method of isolation and in the residue the lens disclosed a number of the olivines which were carefully picked out and subjected to qualitative analysis. This proved the mineral to be a silicate soluble in hydrochloric acid and in the solution were only iron and mag- nesia, lime not being present. The mineral is therefore un- doubtedly an olivine and one rich in iron. The method of isolation also showed that it was very scarce in the rock. The crystals attain a size of ‘5 to 1™™. The presence of olivine in trachytic rocks is not unknown. It is mentioned by Miigge* as occurring in the trachytic lavas of the Azores, by Michel Lévyt in augite trachyte of Monte Dore which is however of an andesitic type, and by Fuchst as an accessory component of the trachyte of the Arso stream on the island of Ischia. Its occurrence in the present case in a magma containing less than ‘5 per cent of magnesia is, how- ever, remarkable and to be paralleled with its presence in the rhyolite of Iceland as shown by Biickstrém,$ and that of fay- alite in the rhyolitic obsidian of the Yellowstone Park, the Lipari Islands] as shown by Iddings. The latter author parallels such occurrences with that of sporadic quartz grains in basalt** and refers their origin to the mineralizing tendency ot included water vapor in highly heated magmas under con- ditions of great pressure. In the present case the corroded state of the olivines evinces that in the later chemical and phys- ical conditions under which the magma consolidated, the com- pound as a chemical one was incapable of existing and that it was therefore formed under different ones. The fact that the magma chilled as a glass proves that it was ejected and cooled with comparative rapidity, and it is reasonable to infer that such ejection through comparatively long and narrow conduits must be accompanied by varying degrees of pressure and with *N. J., 1883, ii, pp. 217. + Bull. Geol. Soc. France, 3d series, xviii, pp. 812. t¢ Tschermak Mitth., 1872, pp. 224. § Geol. Féren. Férhandh., xiii, No. 7, pp. 644. | This Journal, vol. xxx, p. 58, 1885; cf. also 7th Ann. Rep. U.S. G. Sury., pp. 270, 1888. | This Journal, yol. xl, p. 75, 1890. ** This Journal, vol. xxxvi, p. 208, 1888. 384. L. V. Pirsson—Note on some Volcanic Rocks, ete. comparatively slight variations of temperature. Such inerease of pressure may be sufficient to condition the crystallization of compounds which later under lower pressures would be incapable of existing, the mobility of the magma being in- creased by the presence of water vapors as shown by the author cited and thereby conditions more favorable for the production of the compound. feldspar is scattered freely through the glass in small miero- lites of sanidine in flat tables of excessive thinness and twinned according to the Carlsbad law. They are outlined by the base (001), clinopinacoid (010) and positive hemidome (201) and appear as in the annexed figure. They are sometimes solitary and sometimes grouped into somewhat spherical aggregates and thus exhibit the only tendency toward spheru- litie structure observed in the rock. Globulites are present composed largely of minute specks of iron ore as is shown by the colorless zones surrounding them, from which they have extracted the ferruginous coloring mat- ter of the glass. Tuffs ave represented by several specimens. They are soit, light brown in color and enclose fragments of volcanic rock. In thin section they are seen to be composed of fragments of glass which are generally very fresh, mingled with broken erystals of sanidine and angite. In conclusion it is of interest to note that m thus establish- ing, as is evinced by the material investigated, the recent vol- canic nature of this solitary island, there is one more added to that line of mid-Atlantic voleanoes, which sweeping southward through the Azores, Cape Verde Islands, Ascension, St. He- lena, Tristam da Cunha, and Gough’s Island, terminates its voleanie fires on Bouvet Island on the confines of the Antarctic Ocean. Laboratory of Mineralogy and Petrography, Sheffield Scientific School, New Haven, Jan., 1893. A. M. Hdwards—Deposit of Diatomacee. 385 Art, XLUI.—On a Champlain (?) deposit of Diatomacew be- longing to the Littoral Plain; by ArtHUR M. Epwarps, M.D. On the 30th of March, 1859, F. C.S. Roper read a paper by me before the meeting of the Microscopical Society of London, and which was published in volume vii of the Transactions, “On Diatomacee collected in the United States.” In it there is spoken of a gathering made at Hoboken, N. J., in which eighty-six species of Diatomaceze, from fresh, brack- ish and salt water are mentioned as coming from that locality. This gathering, or rather these gatherings, for there were more than one hundred made at that time, were mostly from a large brook, the mud of which yielded the-shells of the dead Diato- maces. At that time I did not try to work out the geology of the deposit, only pointing out that the mixture of marine, brackish and fresh water forms in the deposit was curious. Since that time I have kept the matter in view and am now prepared to assert what I believe to be the geology of the deposit. I shall show that the Diatomaceze in it, and by which its geology is determined, are widely spread. It is the first time that Diatomaceze are found at all in the geological scale and referred to the brackish, although they are indicated by Ehrenberg in the Mikrogeologie, 1854, as coming from Norwich, Conn. This I will show is the same ¢s those. They are known to be marine and are referred to the Eocene, Oligocene or Miocene Tertiary. These are from Paita, Peru; San Pedro (or farther south in Southern California) to Sub Little Mines, Del Norte Co., in California; Petersburg, Vir- ginia, to Atlantic City, New Jersey; Oran, in Africa; Mors, in Denmark; Simbirsk, in Russia; Sentz Peter, in Hungary ; Moron, in Spain; Nicobar island, in the Bay of Bengal; Cuba, Trinidad and Barbadoes, in the West India Islands; Sandai, Kobe and Netanai, in Japan; the Island of Sicily and Omaru, in New Zealand. On the 18th of December, 1871, I read a paper before the Lyceum of Natural History, New York, “On a deposit of marsh-mud upheaval by superincumbent pressure and contain- ing the remains of shells of Mollusca and microscopic organ- isms,” which was not then publisbed, but is now for the first time in the microscopic notes for January 1, 1893. As this records the instance of the shells of marine and brackish Diatomaceze in this deposit also, it now sees the light. The third instance of marine, brackish and fresh-water Diatomacese mixed I have now to publish. This deposit I have studied for over three years past. Besides the many spots on the 386 A. M. Ldwards—Deposit of Diatomacee. Newark meadows, N. J., where I have collected the Champlain (?) deposits, I will mention the following as typical, and from which I have gathered the clay, blue, gray or white, and made slides: Harrison, near the bridge; opposite Athar’s factory ; opposite Lister’s factory ; by Hillingsworth’s factory ; between Hillingsworth’s factory and the P. R. R. bridge; Frank Creek, half way across the meadows; near the P. R. R. No. 1 and No. 2; near the bridge over the Passaic River; on the exten- sion of the P. R. R.; raised meadows on the P. R. R.; Wood- ruff’s Creek, near Elizabeth ; near Linden Park No. 1 and No. 2, Elizabeth ; back of Jersey City; in Jersey City, at the third street from New York Bay; Elizabethport; Bay Way, Eliza- bethport; Kingsland; Sewarren; Kearney; -Peddie Street Ditch; Signal post on the L. V. R. R.,. Bound Creek; and Arrowchar, 8. I., N. Y. Besides these I have the same clay from near New Haven, collected by myself, and also sent to me by Mr. W. A. Terry, of Bristol, Conn. ; near Boston, Mass., from Mr. F. F. Forbes and Mrs. S. A. Fuller; also from Mr. - L. Woolman, as clay, water works, Absecon, N. J.; Bingham House, No. 1 and 2, Philadelphia, Penn.; 11th and Market streets, Philadelphia; Spreckel’s Refinery, Reed Street Wharf, Philadelphia ; abutment Walnut Street Bridge, Philadelphia; Gray’s Ferry, Bb. & O. R. R, and he records in the Microseop- ical Bulletin for October, 1892, “‘ Fossil Diatoms in Philadel- phia beneath the girls’ new Normal School buildings.” And I am also indebted to Mr. C. L. Peticolas for a slide from Corntield Point, St. Mary Co., Md. I have also to record that Professor J. W. Bailey discovered in the earth of the rice fields at Savannah, Ga., Diatomacex. This I received at the same time, about forty years ago, from Dr. W. C. Daniels, Savannah, Ga. Bailey records it in his Microscopical Observa- tions made in South Carolina, Georgia and Florida, and pub- lished in 1850 in the Smithsonian Contributions to Knowledge, Vol. Il, page 5. Dr. F. W. Lewis records the finding of Diatomacez in the blue clay of the Delaware River, Philadel- phia, Penn., in his Notes on new and rarer species of Diato- mace of the United States seaboard, 1861. We now come to mention the species of Diatomaceee found in the Champlain (?) deposits of the Littoral Plain. They include the following: ACHNANTHES hirta, O. F. M., lanceolata, A. de B. Actinocyc.us ternarius, C. G. E. ACTINOPTYCHUS biternarius, C. G. EK. AmMPHIPRORA alata, C. G. E., lepidoptera, W. G., pulchra, J. W. B. AmpuHora cymbifera, W. 8., lanceolata, P. T. C., pellucida, W. G., robusta, W. G., undata, H. L. S. AMPHITETRAS antediluviana, C. G. E. Bresissonta lanceolata, C. A. A. A. M. Edwards— Deposit of Diatomacee. 387 Brpputpaia aurita, A. de B., levis, C. G. E., pulchella, S., radiata, F. C. 8S. R., rhombus, C. G. E., turgida, C. G. E. Campytopiscus clypeus, C. G. E., echeneis, C. G. E. Cocconzts diaphana, W.S., _ distans, W.G., limbata, W. G., major, W. G., oceanica, C. G. E., piacentula, C. G. E., scutellum, CIGs E:, undulata, CGIE, Cocconema cistula, H., lanceolatum, C. G. E. CoLETONEMA eximium, F. T. K., vulgare, T. _Cosctnopiscus asteromphalus, C. G. E., excentricus, C. G. E., lacustris, A. G., nitidus, W. G., radiatus, C. G. E., sol, G. C. W., subtilis, C. G. E. CycLorELLa carconensis, 8. G., operculata, F. T. K., ktitz- ingiana, T. CyMBELLA stomatophora, H. G., truncata, W. G. CyMaToPLeuRa elliptica, A. de B., quinquepunctata, Ff. T. K. Dirtonets apis, C. G. E., elliptica, F. T. K. DenticuLa minor, A. G. Dorrenora amphiceros, F. T. K. Encyonema paradoxum, F. T. K., prostratum, J. R. Epiruemia Jurgensil, C. A. A. ,gibba, F. T. K., gibbula, F. T. K. Hunotia arcus, C. G. E., eracilis, C. G. iD, incisa, W. G., lunaris, A. de B., pectinalis, S. R. FRacitarta Pacifica, A. G., virescens, 8. R. GoMPHONEMA acuminatum, C. G. E., cupitatum, C. G. E., con- strictum, C.G. E.,? curvatum, F. T. K., cristatum, 8. R., mamilla, C. G. E., marinum, W. S. Hyatopiscus scoticus, F. T. K., stelliger, 5S. W. B. Lyrapiscus ovalis, R. K. G. Mastoaetora lanceolata, W. 8., Smithii, T. Meripion cireculare, C. A. A. Me osira crenulata, F. T. K., grandis, M. P., granulata, C. G. E., Jurgensii, C. A. A., nummunloides, C. A. A., punctata, A. G., sulcata, C. G. E., undulata, F. T. K., varians, C. A. A. Navicuta Americana, C. G. E., bacillum, C. G. E., borealis, C. G. E., cancellata, A. 8. D., Couperi, T. W. S., cruciformis var. brevior, P. T. C., cuspidata, F. T. K., dactylus, C. G. E., Dariana, A. G., elegans, F. T. K., esox, C. G. E., firma, F. T. K., gigas, C. G. E., gibberula, F. T. K., gracilis, C. G. E., granulata, A. de B., Henedyii, W. S., interrupta, F. T. K., Lewisiana, RK. G., lyra, C. G. E., major, F. T. K., maxima, W. G., min- utula, W. S., Mexicana, C. G. E., nobilis, C. G. E., oblonga, I’. T. K., peregrina, C. G. E., radiosa, F. T. K., spherophora, C. G. E., stauroneiformis, W. §., (tenuis Grey var. ?) sublineais, W.G. , trinodis, Wiss, viridis, F, T. K., viridula, C. G. E. Nirzscuta, acicularis, raat K,, amphioxys, C. G. E., Bright- wellii, F. Ke bilobata, W. &., constricta, 1d baa eG , compressa, J. W. B., fasciculata, A. Ge obtusa, Ww. G., Peruviana, C.G.E, paradoxa, G., reversa, W. S., scalaris, OC. G. E., sigma, F. T. K., sigma, var. major, A. G., sigmoidea, C. G. E., subrecta var. rigida, A. G., tryblionella, H. , (tryblionella var. ?) littoratis, A. G. PLacrogRamMa Gregorianum, R. K. G. 388 A, M. Hdwards—Deposit of Diatomacee. PievrosieMa angularis, W.S., Balticum, C. G. E., delicatulum, W.S., oximium, F., elongatum, W. S., fasciola, F. 'T. K., hippo- campus, C. G., obscurum, W. 8. Popostra monilformis, C. G. E., Montagnei, I’. T. K. I VXaE AP io altica, wArnG: RwaBpponeMA Adriaticum, L., arcuatuaum, F. T. K. SyneEprRa aflinis, F. T. K., lunaris, C. G. E., pulchella, F. T. K., salina, W.S., tabuiata, F. T. K., ulna, F. T. K. STICTODISCUS craticula. SrEPHANODISCUS corona, C. G. E., Niagare, C. G. E. SravRoNeEIs acuta, W. S., anceps, C. G. E., aspera, W. S., salina, W. S., legumen, C. G. E., maculata, J. W. B., pheenicen- teron, C. G. E., pteroidea, C. G. E., gracilis, C. G. E., fenestra, C. G. E. SURIRELLA acuta, C. G. E., Brightwellii, W. 8., crumena, A. de B., cardinalis, F. K., Davidsonii, A. 8., Fastuosa, C. G. E., gemma, C. G.S., gracilis, A. G., linearis, W.S., Molleriana, A. S., ovalis, A. de B., Ratrayii, A. 8., recedens, A. 8., robusta, C. G. E., splendida, C. G. E., salina, W.58., Suevica, Z. ScHizonEMA cruciger, W.38., divergens, W.S., hyalina, W.5., Smithii, C. A. A. TrerraGcramMa Americana, T. W. B. TaBELLARIA fenestrata, F. T. K., flocculosa, F. T. K. - TRICERATIUM alternans, T. W. B., favus, C. G. E., reticulum, C. G. E. Van Hevurgta rhomboides, A. de B. We now come to the geology of the Newark Champlain (?) deposit. I understand the Champlain deposit to be formed when the melting of the glacier which succeeded the Tertiary age. The first were elaciers forming the glacial period and then they melted and formed the Champlain period. When the glaciers were nearly melted, the Diatomaceze lived in the fresh water, and their shells were deposited when the stream of the Champlain period rushed down from the North. The deposit was mostly clay and covered the states where it is now found. From New Brunswick to Pennsylvania on the Atlan- tic coast of North America it is formed covering the whole country. The clay was of course fresh water, and the Diato- macege were also fresh water. By and by salt water flowed in and formed brackish pools on the coast. As this was raised a brackish clay was formed, and this I call the raised or sunken beach. Dr. J. 8. Newberry calls it the Littoral Plain. He describes it in the geological history of New York Island and harbor in the Popular Science Monthly, vol. xiii. The fresh-water deposits are innumerable, but really are one and form the clay at the bottom. Upon this is the raised coast. The raised coast forms two deposits in the Newark meadows. Upon this is a clay of fresh water Diatomacez, and lastly comes the recent clay now forming. A. W. Whitney—Refraction of Light upon the Snow. 389 Art. XLIV.—Refraction of Light upon the Snow ;* by ALBERT W. WHITNEY. UNDER certain conditions involving the character of the snow and the altitude and brillianey of the sun, the glitter of the snow is not uniform. Make these conditions, then, a cold, clear, winter afternoon, about half an hour before sunset, and a rather fresh field of snow, and the following description becomes general. Two roughly V-shaped paths, of especial, not exclusive, bril- lianey, open away from the observer and towards the sun; the apex of one is perhaps six feet away, its angle 90°; the apex of the other is perhaps 15 feet away, its angle 60°. The following facts are to be noted : First, the light is not diffused; it is made up of many sep- arate brilliant points. Second, the paths are broad, several degrees in width. Third, the inner margin is rather sharply defined; there is no such clear outer limit. Fonrth, the path nearer to the sun is brighter—the separate points of light are visible twice as far away as those in the nearer path. Fifth, while the general glimmer of the snow is apparently colorless, the points which lie in the paths glow most brilliantly with prismatic colors; blues pure and clear as the bluest sky, greens as delicate as the emerald, reds as glowing as the fiery opal. Witha movement of the head which brings a blue crys- tal towards the inner edge of the path, its color passes through all the tints of the spectrum; a movement in the other direc- tion reverses the succession of colors. Within the limits of the path, the colors at first seem to be scattered promiscuously ; more careful observation, however, leads one to feel that there is a slight tendency in the reds to keep to the inside. A large number of measurements with the sextant have made it evident that the angle between the eye, the glowing point, and the sun, is not only constant as regards all other points of like position on the path but also for varying altitudes of the sun. The supplement of this angle, measured from the part of the greatest brilliancy, is for the nearer path about 46°, for the further path about 22°. Let us eall this in general 0. Without seeking a cause for the condition, it is easy to deter- mine what, under this condition, the path must be. The locus of points at which a constant angle is made between * Abstract of a paper read before the Beloit College Scientific Association, Feb- 14, 1893. 390 A. W. Whitney Leefraction of Light upon the Snow. parallel lines and lines to a given point is the surface of a cone. In this case, the eye is the apex, the axis the line of sunlight, the angle at the apex is 20. It will be seen at once that the snow-surface is a plane which cuts this cone. The conie see- tion produced depends upon the relation of the altitude of the sun and 0. In both cases, where d = 22° and 46°, the figure on the snow is evidently a hyperbola. When the altitude of the sun = 0, the figure is at infinity; the sun has an altitude of more than 22° till about the middle of the afternoon; hence before this time the inner hyperbola is invisible. As even at noon the sun is not higher than 37°, the outer hyperbola is visible at all times. The effect of the going down of the sun is evidently to broaden the figures and bring them nearer. We have now proved inductively that 0d is constant, and de- ductively that, d being constant, the figure is an hyperbola. It remains to find a cause for the constancy of 0. The light from the snow is evidently due either to reflec- tion or refraction; most of it is doubtless reflected. Several facts already mentioned seem to prove, however, that the light of the hyperbolas is not due to reflection. First, the only intrinsic law of reflection, that of the equality of the angles of incidence and reflection, is seen to be no*path- discriminating condition—for the facets of the snow-crystals may be tilted at any angle. Second, reflection cannot account for the color. Therefore this phenomenon must be due to refraction. The difference is apparent between the light from the crystals lying in and out of the path. As one turns his head, those crystals lying out- side flash for an instant, and as quickly subside; those in the path, on the other hand, linger to run through their little life of color. At noon the altitude of the sun is about 37°; the complement of the polarizing angle of ice is 37° 20’. Hence at this time the reflected light near the vertex of the hyperbola should be nearly all polarized. Experiments with Nicol’s prism and tourmaline prove that nearly all the general glim- mer is cut off, while the light of the hyperbola is undisturbed. The problem is now simplified to that of finding a phenome- non of refraction to correspond with the constancy of 0. The angle of minimum deviation seems to promise a solution ; it will evidently give a maximum, for at this point the refracted light is greatest. It will also give a sharp inside limit to the path and an indefinite outside limit, which exactly corresponds with observation. Now ice belongs to the hexagonal system; it may form in right hexagonal prisms. Consequently a snow-erystal may offer to the light angles of 60°, 90°, and 120°. There will evidently be no emergence in the ease of the 120° angle. A. W. Whitney—Lefraction of Light upon the Snow. 391 The formula, 0=2 sin~'(”sin > ]—A, gives for the angles A | of minimum deviation, where 7, the refractive index of ice, is 1°31, and A is first 60° and then 90°, the angles 21° 50’ and 45° 44’, which correspond very closely with observation. The greater brilliancy of the 22° hyperbola corroborates the theory also, for evidently less light is transmitted through a 90° prism, than through one of 60°, owing to the greater obliquity of the incident rays in the former case. To sum up, in a field of snow-erystals tilted at all possible angles, not one can send a refracted ray to the eye unless, first, it lies in the path of the hyperbola, and, second, it is tilted at just the right angle. The resemblance of this theory to that of halos, or, in fact, the real unity of the two, is manifest. The halo and the snow- hyperbola are respectively the aerial and terrestrial portions of the same phenomenon ; the comparison in detail is very inter- esting. Some rays of light doubtless experience internal reflection. Hence other conic sections are within the range of possibility. The simplest such case, that of one internal reflection, where the maximum is given by the critical angle, would give angles corresponding to 6 of about 87° and 116°. Some color may be- seen throughout this region, but I have not been able to detect anything definite enough to be called a path. The perspective of these snow-hyperbolas for ms concentric circles upon a plane normal to the path of the sun’s rays, which is also evident from the fact that they are the completion of the halos. On a vertical plane the perspective forms ellipses. Another interesting fact concerns the relation of the other limb of the hyperbola to that upon the snow. If the observer walks so as always to keep one certain point in the path of light, his track will be an hyperbola; if now, from the apex of the hyperbola which he has traced, he advances a distance equal to his height multiplied by the cotangent of the angle, the altitude of the sun plus 0, the figure which he now sees and the figure which he has traced upon the snow are the two limbs of the same hyperbola. The difference between the refractive indices for red and violet light gives theoretically a dispersion of 46’ in the case of the hyperbola of 22°, and of 2° 10’ in the case of the hyper- bola of 46°. It may be noticed that the colors in the nearer figure are more conspicuous. I do not understand, however, why the arrangement of color is not more regular. It may be due to an inability of the eye to sum up this discrete color. The hyperbola is produced by a single layer of crystals, the 392 Moreland—Force exerted by a current of Electricity. halo by a mass of crystals perhaps hundreds of feet in depth; hence in the latter case the summation is already made. Refraction upon the snow is largely, perhaps mostly, due to frost-erystals. They form more slowly, hence more regularly, than snow-crystals ; they are inconspicuous upon a snow-surface. Snow-hyperbolas are usually more obvious in late afternoon than in the early morning. I have thought that possibly the following may be in the line of an explanation of this: the frost-erystals need a certain amount of clearing up by sun and wind of minute secondary accumulations of frost upon them- selves, to make them fit for transmitting light. Art. XLV.— Value of the force exerted by a current of Elec- tricity in a circular conductor on a unit magnetic pole at its center ; by S. T. MoRELAND. THE following method of finding this value is new so far as I know. Let z=strength of current 7=mean radius of the conductor supposed to make one turn. So far as magnetic effects are concerned it is known that such a current produces the same result as a magnetic shell having its boundary in the circle and satisfying the condition It where / is the uniform surface density of the magnetism and ¢ is the thickness of the shell. Substitute a hemispherical mag- netic shell for the current in this case having plus magnetism on the inner surface and minus on the outer, the total quantity on each of the two surfaces being equal. Let o, =surface density on inner surface. or — (45 (74 (74 outer (13 7, =radius of inner surface. r= ce (74 outer <4 Then 7,—7,=t, a very small quantity, and r=/7r,7,= e Y id Oo oO ny very nearly, and /= V6, = very nearly. S. L. Penfield—Cookeite from Maine. 393 We al Also GB siaa—a hae rp Ohare t, he: rs Similarly GT _ The resultant repulsion of the magnetism of the inner sur- face on the unit pole at the center is zo, and the attraction of the outer surface is zo, Hence, Resultant force of magnetic shell=z(a,—<,,) v, 4 aa = 71 Giant) (@, ely) mi 27% Sh) = which is the result sought. We see too that in the equation 5 I is the mean of the two surface densities which must neces- sarily differ in value unless the shell is a plane. Art. XLVI.—On Cookeite from Paris and Hebron, Maine ; by Samuet L. PENFIELD. THIS mineral was first described as a new species in 1866 by Professor George J. Brush,* and only a limited supply of pure material could be obtained at that time for the chemical analy- sis, which was made by Mr. Peter Collier. In the summer of 1891 Professor Brush visited the localities of Paris and Hebron and obtained there some excellent specimens of Cookeite, from which abundant material suitable for analysis could be obtained, and at his suggestion the mineral has been reéxam- ined. Cookeite is related to the chlorites and micas, having a dis- tinct basal cleavage and erystallizing like them in the mono- clinic system. The largest crystals that the author has observed are not over 3™™ in diameter and are hexagonal in habit. Dis- *This Journal, II, xli, p. 246. 394 S. L. Penfield—Oookeite from Maine. tinct six-sided prisms are rarely found; the erystals are usually radial as if made from a series of wedge-shaped hexagonal plates, fig. 1, grouped with their thin edges together, fig. 2. The form is something like that of prochlorite, figured on page 653 of the sixth edition of Dana’s Mineralogy, only more bent. The exterior of the crystals is rather rough, so that they look almost hemispherical or globular. The cleavage plates are naturally wedge-shaped like fig. 1, which interferes somewhat with making exact optical determinations. When examined in polarized light they appear divided up very sym- metrically into sectors fig. 3. The inner portion @ is uniaxial and shows a weak, positive double refraction. The outer por- Ne 2. 3. SS tion or rim is composed of six segments, the opposite ones extinguishing simultaneously in directions indicated in the figure, showing that this outer portion may be regarded as a trilling, composed of penetrating individuals. In each seg- ment the acute bisectrix is about at right angles to the section and the plane of the optical axes is parallel to the edge of the hexagon, corresponding to the clinopinacoid. The bisectrix is also slightly inclined in the same plane. The divergence of the axes is large, considerably greater than that of muscovite, although it could not be measured exactly owing to the small size of the sections. The double refraction is positive and not very strong, being about like that of the chlorites. The uni- axial central portion a, fig. 3, may be considered as composed of biaxial plates, superiraposed on one another in twin position according to Tschermak’s law of twinning for the chlorites.* The relative proportion of center and rim varies. In some sections the center is almost wanting, the rim, however, is always prominent and shows with the microscope a faint striated structure, the striz running at right angles to the edge of the hexagon, as represented in the figure. Except for the uniaxial center the above method of twinning is exactly like that of the clinochlore from Texas, Lancaster Co., Pa., described by Professor J. P. Cooke,+ after whom this mineral was named. * Sitzungsber. d. kais. Akad. d. Wissenschaften in Wien (1), xcix, p. 174, 1890. + This Journal, II, xliv, p. 201. S. L. Penfield— Cookeite from Maine. 395 Cookeite is associated with quartz, lepidolite and tourmaline (especially the variety rubellite) and apparently has resulted from the alteration of the latter, as suggested by Professor Brush. One of the best and most interesting specimens of the mineral in the Brush collecticn is a deposit of the mineral on a large tourmaline crystal. This latter has a triangular pris- matic habit, terminated by a basal plane and is over 4%™ in diameter. As a subsequent process the tourmaline has been mostly removed, leaving a cellular interior, containing cookeite, a few quartz crystals and remnants of the original tourmaline, etched out into slender prisms and spicules reminding one of the etched beryls (aquamarines) from Mt. Antero, Colorado.* The cookeite here is plainly a secondary mineral and in this respect, as well as in its crystalline habit, mode of twinning and optical properties it is related to the chlorites. It is also like some varieties of vermiculite in its pyrognostic properties. When heated before the blowpipe it exfoliates prodigiously, giving at the same time a lithia color to the flame. The material for analysis was carefully selected from a speci- men from Paris where the cookeite was associated with quartz and tourmaline, thereby avoiding any contamination with lepidolite. The results of the analysis are given below to- gether with the original analysis of Mr. Collier. Author. Collier. Specific gravity 2°€75 2°70 Ratio. I. JUL Mean. poset ee he ee Mean. SiO, 34-00 34:00 567 4-00 34:93 Al,O, 45°13 44:98 45:06 442 3-11 44°91 Fe,O, 0°45 0°45 CaO 0°04 0°04 KO. = (sll CG OZ 001 2°57 NakO2 0:20 02%. 40219 7003 +°138 = 0°97 Li,O 4°14 3°89 4°02 134 2°82 H,O 14°85 15°06 14°96 Soleil. ‘ 13°79 Fr 0-46 046238 012 BiB, 0-45 O equivalent to the F 99°32 99°49 19 99°13 The ratio in the author’s analysis corresponds closely to pie ALO. LO 2 Or— 413) 21/ 6 \eivine the’ formula H,,Li,A1,Si,O,,, or simplified to that of a basic metasilicate, 249 * This Journal, III, xl, p. 488, 1890. Am. Jour. Sci1.—THIRD SERIES, VOL. XLV, No. 269.—May, 1893. 396 S. L. Penfield—Mineralogical Notes. Li{Al(OH),],Si,0,. Below will be found the author’s analysis simplified by regarding all of the alkalies as represented by their equivalent of Li,O, the Fe,O, as Al,O, and the F as OH and the whole calculated to one hundred -per cent, also the per- centage composition from the proposed formula. Analysis as adjusted. Theory. Si0, I a pee 34°46 35°09 Al O, Uc vara Ltd Reet ate 45°95 44°74 Li,O Seeo NT each SBS 4°21 4°38 H,O ene Serene pe 15°38 15°79 100°00 100°00 The agreement is certainly satisfactory. and the discrepancy is probably the result of some slight impurity, which it is hard to avoid in micaceous minerals. Most of the water is expelled from cookeite at a high temperature, showing that it is proba- bly formed from hydroxyl as assumed in the formula given above. The analysis was made on air-dry powder and the fol- lowing fractional determinations were made: Twenty hours over sulphuric acid in a desiccator, 0°82 per cent loss. One houtjat MOO Cwa= hia es sae al ea yee 0:09). Ries One hour at 300° C. (to constant weight) -- .- 0-91 “ ff 6 Bo ee ee pe eee Oe ee ee Ts 1°82 ss ie If this small amount of water is deducted from the analysis the ratio of SiO,: H,O is nearer 4:5 but the formula then becomes much more complicated. The essential difference between the author’s analysis and that of Mr. Collier is in the alkalies, and it is impossible to give any explanation of his potash determination except that the material for the same was possibly contaminated with lepidolite. Mineralogical Laboratory of the Sheffield Scientific School, New Haven, January, 1893. Art. XLVII.—Mineralogical Notes; by SamusE. L. PENFIELD. THE author takes this opportunity of expressing to the Director of the U. S. Geological Survey his obligations for the privilege of presenting the results of the following mineral- ogieal studies, which have been made upon material collected by the writer during the summer of 1892, while engaged in survey work. S. L. Penfield—Mineralogical Notes. 397 1. Zunyite from Red Mountain, Ouray Co., Colorado. In 1884 Mr. W. F. Hillebrand* described a new mineral zunyite from the Zufi Mine, near Silverton, San Juan Co., Colorado. It is interesting to know that a second locality has been found for this rare mineral, at the Charter Oak mine, situated on the hill, only a short distance east of the village of Red Mountain. This is about five miles north of the original locality and on the same mountain chain. When visiting the mine, my attention was called by the superintendent, Mr. C. A. Taylor, to a very hard rock which had been taken from the shaft. This is fine grained, of a grayish white color, and with the lens one can readily detect the little bright tetrahedrons of zunyite, about 1™™ in diam- eter, sometimes scattered sparsely, sometimes abundantly, through it. An examination of thin sections with the micro- scope shows that the rock is a porphyrite, very much altered by steam and fumerole action, so that only remnants of the original minerals are left. The zunyite crystals are fresh and clear and show no double refraction with polarized light. The pulverized rock was almost an ideal one to treat with the Thoulet solution. An approximate separation of the zunyite crystals was first made. This product was then further purified by digesting with dilute hydrochloric and hydrofluoric acids, which have no appreciable solvent action on the zunyite, and then again separated with the heavy solution, giving a very pure product. Most of the mineral had a specific gravity between 2°904 and 2°876 and only this portion was used for the chemical analysis, the results of which are given below, together with the original analysis of Mr. Hillebrand. i Il. Average. Ratio. Hillebrand. STOpss.eae 24°11 24°10 24-11 *402 3°00 24°33 INAVR ese oe 57:20 57°20 “561 4:18 57°88 Fe.0; Se ‘61 ‘61 20 (OLS ula eae 2°61 2°62 2°62 “074 2°91 1 Doe area 5:92 5-70 5°81 °306 + 1616 12 06 5°61] EGO aa 11°06 11°18 11°12+9=1°236 10°89 PO gress “64 “64 “60 CaO ees Hal ale; K.O :10 IN, Oe a= 48 “48 24 102°70 102°76 O equivalent to Cl and F 3:03 3:02 99°67 99 74 The analysis was made on air-dry material which lost only 0:06 per cent by drying for one hour at 100° C. and an addi- tional 0°15 per cent by heating for one hour at 300° C. The water is therefore regarded as formed from hydroxyl, with * Proc. Col. Soc., i, p. 124, 1884. Also Bulletin No. 20, U. 8. Geological Survey, p. 100. 398 S. L. Penjfield— Mineralogical Notes. which the Cl and F are isomorphous. Disregarding the small amounts of P,O,, CaO. Na,O and Fe,O, the ratio of SiO, : Al,O,: (Cl. F.OH) is nearly 3: 4:12, which is required by the formula suggested by Professor P. Groth® [AI(CL F.OH),], Jalen Or. The agreement between the author’s and Mr. Hille- brand’s analyses is very satisfactory. Especially the percent- ages of Cl, F and hydroxyl, which are regarded as isomorph- ous, are very close and yet there seems to be no definite pro- portion in which these constituents are related to one another. The relation of Cl+ F: OH in the author’s analysis 1 is 380: 1°236 or 1; 3°25. Besides the occurrence of zunyite in the rock, as just de- scribed, it also occurs at this same mine in a pulverulent form. This material resembles some kinds of kaolin, is pure white and consists of minute crystals, so loosely aggregated that they can be disintegrated by rubbing between the fingers. Other minerals found at the mine are enargite, pyrite, scorodite and sulphur. The latter in small but highly modified Glas showing the faces, 100, 2-2; 010, 2-2; 110, 7; 101, 1-2; 103, 4 OMI tepSculi ke Wl Bealls} ices 115, 3 Teandulsee leas The keene was determined by proving it to be a hydrous ferric arseniate of specific gravity 3-209. It is not crystallized but has formed as a green, botryoidal incrustation on the enargite and decom- posed rock. The author also visited the Zufi mine near Silverton where the zunyite occurs intimately mixed with the sulpharsenite of lead, guitermanite, and an earthy decomposition product con- taining lead sulphate, as described by Mr. Hillebrand. Some crystals were also found in the wall rock, which, like that from Red Mountain, is a decomposed porphyrite. At both localities zunyite is plainly a secondary mineral and has probably been formed by fumerole action upon the silicates of the rock. The author takes pleasure in expressing to Mr. C. A. Taylor of Red Mountain, and to Mr. R. H. Williams of Silverton, the discoverer and owner of the Zufi mine, his obligations for their kindness in supplymg him with specimens and infor- mation. 2. Nenotime from Cheyenne Mountain, Hl Paso Co., Colorado. The occurrence of this mineral from the tysonite and bast- naesite locality of E] Paso County has already been noted by Mr. W. E. Hidden.+ His description was confined to a single crystal, measuring over one centimeter in diameter, weighing 5‘1 grams and which had suffered some superficial alteration. The crystal to be described in the present article was given to * Tabellarische Uebersicht der Mineralien, 1889, p. 104. + This Journal, xxix, p. 249, 1885. a Browning—Ffiree Nitric Acid and Aqua Regia, ete. 3899 the writer by Mr. J. G. Hiestand of Manitou, Colo. It is over one centimeter in diameter and is implanted on a gangue of quartz and feldspar. Associated with it are crystals of hema- tite and astrophyllite. The xenotime is very fresh and pure, has a brown color and in thin splinters is pale pink. The form of the crystal is the unit pyramid with its middle edges slightly modified by the prism and a steeper pyramid, probably 331, but the faces of the latter were too dull to measure on the reflecting goniometer. The faces of the unit pyramid were bright and the following measurement was made, 111, 111= 55° 32’, agreeing very well with the measurements of G. vom Rath* and ©. Klein,t 55° 30’. The prismatic cleavage was very well shown by cracks running through the crystal. Without destroying the specimen a little over 0-2 gram was removed for a quantitative analysis, the results of which are as follows: Specific gravity 5°106 Ratio. P.O, 32°11 + 142= -996 1-00 (to ET) ROMN NG 7-16n == 294 — 238) IL05 Ignition 18 100°07 The only metals that were found were those of the yttrium and erbium group and the joint molecular weight of the oxides was found to be 284, equivalent to a joint atomic weight of 118. A solution of the oxides tested with the spec- troscope showed the absorption bands of erbium and _ the atomic weight indicates that yttrium is also present. The ratio of P,O,: (Yt, Er),O, is almost 1:1 showing that the min- eral isa normal phosphate. The author desires to express his thanks to Mr. J. G. Hies- tand for giving him this interesting crystal which is now in the United States National Museum. Art. XLVII.— The Influence of Free Nitric Acid and Aqua Regia on the Precipitation of Barium as Sulphate; by Puitie E. BROWNING. [Contributions from the Kent Chemical Laboratory of Yale College—XXII.] THE fact demonstrated by Dr. F. W. Mart in an interest- ing series of experiments, that free hydrochloric acid even in large quantities does not interfere with the complete precipita- tion of barium as sulphate when sulphuric acid is present in * Pogg. Ann., 1864, B. 123, p. 187. + Jarb. Minn., 1879, p. 536. ¢ This Journal, xl, 283. 400 Browning — Influence of Acids sufficient excess, but rather renders the precipitate more erys- talline, and therefore more easily and quickly filtered, suggested a similar series of experiments having as their object an inves- tigation of the influence of free nitric acid on the same pre- cipitation. Certain qualitative preliminary experiments showed a similar effect to that brought about by hydrochloric acid as regards the crystalline form and rapid settling of the precipi- tate. It therefore remained to determine whether the nitric acid present had any solvent effect upon the precipitate. Accordingly a standard solution of barium nitrate was pre- pared, free from alkali, by precipitating a soluble barium salt with ammonium carbonate, washing thoroughly with hot water and dissolving in nitric acid, care being taken to avoid an excess of the acid, and making up to measure. Definite por- tions of this solution were drawn from a burette into counter- poised beakers, and weighed as a check on the burette reading. Several precipitations of the barium in the form of sulphate were made, both in the presence of free hydrochloric acid and in neutral solution, and the mean of closely agreeing deter- minations was taken as the value of the standard solution. The mode of procedure in the testing was simple and may be outlined as follows:—Into a counterpoised beaker a definite amount of the standardized solution of barium nitrate was drawn and the weight taken as before described, the amount of nitric acid to be used was then added, and the whole volume brought up to 90 em* by the addition of water. This acid solution was then brought to the boiling point and 10 em* of the dilute sulphuric acid added, and the whole was allowed to stand for the length of time shown by the table before filter- ing on asbestos, Ts and weighing. . It will be seen that the total volume of liquid taken in each determination was uniformly 100 em*, the percentage of acid by volume being thus easily regulated. In no case did the amount of barium salt present exceed 0-4 gm. considered as the sulphate, and con- sequently the uniform amount of 10cm* of dilute (1:4 by volume) sulphuric acid employed was always enough to assure the excess which Fresenius* has shown to be necessary in the precipitation of barium as the sulphate in the presence of hy- drochloric acid. By reference to Series I it is evident that in the presence of five per cent of nitric acid very little solvent action is shown, and it appears also that the sulphate may be safely filtered after an hour’s time. In the presence of ten to fifteen per cent of the acid the solvent effect is very small when the solution is allowed to stand six hours or more. With twenty to twenty-five per cent of acid present we find the solubility to be slightly increased, but even then the average loss is less than 0-001 grm. * Zeitschr. f. anal. Chem., xxx, 455. on the Precipitation of Barium as Sulphate. BaSO. equivalent to Ba(NOs)s taken. grm. (1) 06-2540 (2) 0-2489 ( 3) 0°2495 (4) 0°2492 (5) 0°2486 ( 6) 0:2490 (7) 610-2555 (8) 0:2538 (9) 0:4067 (10) 0 2540 Ql). 072492 (2) 02493 (13) 0:2494 (14) 0°2492 (15) 0°2490 (16) 0°2489 (17) 0°2540 (18) 0°2529 (19) 0°2534 (20) 0°2533 (21) 0°2538 (22) 0:24.97 (23) 0-2489 (24) 02542 (25) . 0:2486 (26) 0°2492 (27) 0°2547 (28) 0:2489 (29) 0-2486 (30) 0°2548 (31) 0 2548 (32) 0°2496 (33) 02253 (34) 0-2488 (35) 0°2497 (36) 02486 (37) 0:2491 (38) 0°2494 (39) 02538 (40) 02492 (41) 0°2487 (42) 073414 (43) 9°2489 (44) 0°2485 BaSO, found. grm. 0°2336 0°2483 0°2489 0°2482 0°2483 0:2490 0°2546 0:2534 0°4057 0°2533 0°2489 0:2488 0:2488 0°2492 02489 02484 0°2524 0°2515 0:2522 0°2531 0°2532 2 "2542 2 SERIES I. Error in terms of BaSOx,. erm. 0-0004— ) 0:0006— |! 0-0006— PO OvOs— 0-0010— J d 00002 — j Averages. erm. 0-0010— ) 0.0007 — 0:0003— $0-0006— 0-0005— | 0:0006— J 00002 0°0000 00001 — 0 0016— 0°0005 — 0:0016— 0:0014— ) 0:0012— | 0:0002— |! WONG + 00007 — 0:0007— | 0-1002— | 0:0014— ) 00000 00005 — \ 0°0015 — 0°0006— 0:0015— 0-00LI— ) 0:0011— | 0:0002— }+0-0008— 0:0006— 0-0010— 0:0012 — 0:0013 — 00000 0°0009 — 00001 — 0:0010— 0°0603— +0:0008— 0 0008— | 0:0008 — } | 0°0016— 0-0007— | 0;0008==").-) in {0-007 — Time be- tween pre- cipitation and filtra- tion. hours. 12 al vc 6 1 vb Per cent by volume of strong HNOs. 401 Total volume. 2 cm? 100 vc Having shown that free nitric acid even though present in considerable amount has only a slight solvent influence upon barium sulphate it seemed interesting to try the effect of the combination of nitric and hydrochloric acids mixed in the pro- portion to form aqua regia (83HC1: LH NO,). The experiments 402 Browning— Influence of Acids recorded in Series II show that aqua regia has even less effect as a solvent than nitric acid alone. In fact it seems to act like hydrochlorie acid alone, which practically has no solvent effect, as shown by Dr. Mar’s work previously cited. SEkIEs II. Time be- Per cent BaSO, tween pre- by volume equivaleut to Error in cipitation of Ba(NOs). BasO, terms of’ and filtra- strong Total taken. found. BaSQ,. Averages. tion. aquaregia. volume. erm. erm. erm. grm. hours. (3HC!: 1HNOs). em? 022539 0°2534 0°:0005— ) 12 5 100 2) 0°2540 0-2538 0:0002— }+0°0002— at 0 3) 0-2490 0:2490 0-0000 ‘J ‘ “ “ 4) 0°2491 0°2492 0:0001 + ) 2 : tr 5) 0:2488 0:2484 0:0004— + 0-000] — 6 tt st ( ( ( ( ( (6) 03419 03421 000024 | : “ “ (7) 02491 0:2487 0-0004— } 12 10 u (8) 02486 0-2482 0-0001— |, (9) 0-2549 0-2539 0 0010—. (0 0006— (10) 02543 0-2538 0-0005— J (11) 02487 0°2485 ~—-0-0002— | o-0002— : (12) 03416 03415 6-0001— 4 u : « (13) 0-3417 0°3420--0-0003+ +~—:0:00034 ~— 1 “ : (14) 0°2547 0:2544 0:0003— ) 12 15 Satie (15) 0°2492 0:2492 0:0000 00003 — at i oa (16) 0°2489 02479 =0 0019— cs i (17) 0°3412 0°3412 0°0000 | (18), (034180 03417 OK000T— 1h ace u “ (19) 0:3413 03412 + o-ooo1— ¢ 9009! ‘“ ‘ “ (20) 0°3411 03402 ~—«0:0009— +: 0-0009— 1 u r (21) 02492 0°2484 + —0-0008— 12 20 r 22) 02486 0:2480 0-006 — “ “ oS 02491 0:2485 o-0006— f200%— x “ “ (24) 03412 0°3411 0-0001— | r “ “ (25) 0°3417 02418 00001 + {o-0000 : (26) 0°3417 0°3417 —_-0-0000 u : “ (27) 03414 03404 0-0010—-0-0010——s 1 “ “ (28) 0-2491 00-2485 ~—-0-0006— ) 12 25 r (29) 01701 0:1697 00001— |. : u r (30) 01708 0-1705 o-0003— fF90008— a “ “ (31) 01710 01710 0:0000 | \ 4 (32) 03415 0°3410 0:0005— Vago, r ‘ (33) 0°3418 03418 —0-0000 r i M (34) 0:3412 03405 0:0007— 0-0007— 1 : ‘ In this connection I append the results of a few experiments made to determine the effect of the presence of a considerable amount of free nitric acid, on the precipitations of barium as sulphate in cases where certain substances are present which under ordinary conditions tend to hold up the precipitate. Fresenius* has demonstrated this property in the case of ammonium nitrate, Scheerer and Rube,t have shown that * Zeitschr. f. anal. Chem., ix, 62. +Erdm, Jour. prakt. Chem., Ixxy, 113-116. on the Precipitation of Barvum as Sulphate. 403 metaphosphoric acid acts similarly, and Spiller* notes the same general effect where alkaline citrates are present. Series III shows the results obtained by precipitating definite portions of the standard solution of barium nitrate in the presence of stated amounts of the substances just mentioned. The total volume in every case was 100 em’, the amount of dilute sul- phuric acid used 10 em*, and the time between precipitation and filtration twelve hours. Upon filtering, igniting and weighing the barium sulphate an excess of weight, due un- doubtedly to contamination of the precipitate, was found. It became necessary, therefore, to purify the precipitate as first weighed in order to determine whether all the barium was actually precipitated or whether a partial loss was covered by the amount of included impurity. The method of purification employed was that successfully applied by Dr. Mar in the work previously mentioned. The contaminated sulphate, collected on paper and treated according to the familiar method (on account of the difficulty attending the complete removal of the precipitate from asbestos for purposes of purification), was dis- solved in warm concentrated sulphuric acid, and evaporated quickly and without spattering by means of the Hempel burner, the barium sulphate being left after this treatment in coarse granular crystals. The crystallized sulphate was warmed with a little water containing a drop of sulphuric acid, filtered upon an asbestos felt contained in a perforated platinum eru- cible, the crucible and felt having been previously ignited and weighed. Serirs III. Apparent Error Percentage Impurity present BaSO,equiva- amountof BaSO, after after of strong to the amount of lent to Ba(NOs3). BaSO, purifica- purifica- HNO; by 5 erm. taken. found. tion. tion. volume. erm. erm erm. erm. (1) Ammonium nitrate 0°1710 01800 01702 0:0008— ~=10 (2) ve 0°3415 0°34490 0°3410 0°0005— ue 3 "4 citrate 0°3412 0°3442 0°3407 0:0005 — (4) Sodium ot 071360 01730 0°1366 0°0006+ . (5) Metaphosphoric acid 0°3461 0:3511 0:3470 0°0009 + ze The results show that in the presence of nitric acid amount- ing to one tenth by volume of the entire liquid these salts exert no apparent interference with the precipitation of the barium. The entire work would seem to show that the presence of an excess of nitric acid or aqua regia amounting to ten per cent by volume of the liquid treated is not only not to be avoided in estimating barium as the sulphate, but is actually beneficial. Ordinarily the advantage is found in the tendency * Chem. News, viii, 280-281. 404 W. H. Hobbs—Lime- and- Alumina-bearing Tale. of the precipitate to fall coarsely crystalline under the con- ditions. In certain special cases in which certain substanees mentioned, which would otherwise exert solvent action, are present the precipitation is made complete. The contaminat- ing effect of such substances when complete precipitation is induced may be corrected by dissolving the precipitate in sul- phurie acid and recrystallizing by evaporation. Art. XLIX.—On a Rose-colored Lime- and- Alumina-bearing Variety of Taic; by Wu. H. Hosss, Madison, Wis. THE crystalline dolomite of the vicinity of Canaan, Conn., is well known as a locality for white pyroxene and white and pale green tremolite. Some of this tremolite has recently been shown to be pseudomorphic to the white pyroxene.* Small amounts of quartz and colorless mica, and isolated crystals of pyrite, are present in the rock at many localities, and veins of calcite are occasionally met. Except near the boundaries of the horizon, where the rock passes by gradations toward a gneiss or schist, these are the only common minerals. Phlogo- pite I have found in clear brown scales a millimeter or more in diameter on the road running south from Rattlesnake Hill. The numerous openings which are made in the dolomite for supplying the lime-kilns of the vicinity, furnish opportunities for the discovery of any less common constituents that may be included in the rock. Mr. J. S. Adam, former analyst of the Barnum and Richardson Company of Lime Rock, has in his mineral collection at Canaan, several minerals of this character which have not been carefully studied. I am under obliga- tions to him for the material which is here described. It was met with in the Adam Quarry which is located a mile south- east of the village of Canaan. The specimens given me are enclosed in the white crystalline dolomite whose grains average two millimeters in diameter.t Scattered through the dolomite * Wm. H. Hobbs, Notes on some Pseudomorphs from the Taconic Region, Am. Geol., x, 44 (1892). +I am permitted by Mr. Adam to publish analyses by him of the dolomite of the vicinity, which show it to contain calcium and magnesium carbonates in the proportions of normal dolomite: Canaan Lime Company’s Quarry. Calculated for Granular. Cleavage Pieces. CaCO;. MgC0Os. Cat Oger es hs wae 52°62 54:40 54°35 Me COs ea Aeneas 46°25 45°12 45°65 Fe.03 “97 Al,O, t ism a ee 0 24 0°25 Insoluble residue _. 017 0:08 99 28 99°85 100°00 Pe a oe W. H. Hobbs—Lime- and- Alumina-bearing Tale. 405 are simple pentagonal dodecahedrons of pyrite about a milli- meter in diameter, which are colored brown from superficial alteration to limonite. On lines evidently corresponding to fracture planes in the rock, is developed a talcose mineral. Other fracture lines are occupied by vein dolomite, one cleav- age surface extending several centimeters. In one of the specimens the talcose mineral has a deep rose color, somewhat deeper than that of the margarite from Chester, Mass. In the other specimen the color is white or nearly so, but Mr. Adam informed me that when found it had the same rose hue as the first mentioned specimen. The rose color has faded through exposure to the light, resembling in this respect rose quartz. The sealts of this taleose mineral lie with entire lack of any regular orientation, completely filling the fissure. Scales one- half a centimeter across can be obtained having roughly hexag- onal outlines, but which are too poor for accurate measure- ment. They are very flexible but entirely inelastic. They have the softness and unctuous feel of ordinary tale. After treatment with dilute hydrochloric acid to remove any pos- sible trace of calcite, nearly a gram of the material gave a specific gravity of 2°86 by determination with the pyknometer. In the closed tube the powdered mineral yields considerable water. Ignited before the blowpipe it resembles tale in exfoli- ating, whitening and glowing intensely. It is, however, much more fusible, falling below 5 in v. Kobell’s scale. It is also more readily decomposable than common tale. When digested for only a short time in hydrochloric acid, the solution yields a considerable amount of alumina and calcium. Between crossed nicols in convergent light, scales of the mineral show a negative bisectrix perpendicular to the plane of cleavage. The optical angle, which is very small, lies in the plane perpendicular to one of the bounding planes, and also perpendicular to a side of the hexagon of the percussion figure. It therefore corresponds to a mica of the first class. 2H was measured in sodium light as 153°. I am indebted to my friend, Mr. Louis Kahlenberg of the University of Wisconsin, fora chemical analysis of this mineral. His results are given below in the first column. Inthe last column is given the theoretical composition of ordinary talc: 406 W. H. Hobbs—Lime- and- Alumina-bearing Tale. Calculated for HaMgySiyOy2 Givin. + by ee esaltel Oiediee) emus Alii pok ac Clay eeroay caee 63°52 MgO) see ae Mewar 25 2540) OFC Wate Sanwa e eee rots AAD lp nee pe MeOiecachee sce ak 0:77 peo 31°72 Mn ORs saa searatnacel) FLO aps eso 5°54 4°76 100°56 100°00 The mineral contains no nickel. The analysis corresponds to a normal tale in which the mag- nesia is in part replaced by lime and the silica by alumina. The trace of manganese accounts for the rose color of the mineral which is lost on exposure to sunlight. The large amount of lime present is doubtless the cause of the unusual fusibility and decomposability by acids. Small amounts of lime in tale are not altogether unusual, though I have been unable to learn of but three analyses of the mineral, which have yielded more than one per cent of lime. These are given by Hintze in the list of sixty-seven analyses of tale printed in his Handbuch der Mineralogie.* The three occurrences referred to are Plaben, Bohemia (CaO, 1:09 per cent); Bergen Hill, New Jersey (CaO, 1:41 per cent); and Campo Longo (?), Tessin (CaO, 3°70 percent.) The presence of alumina in tale would not seem to be so unusual, since the same list includes four ocecur- rences of tale characterized by as large an amount of alumina as the Canaan mineral. They are, Plaben, Bohemia (A1,O,, 3°27 per cent); Gasteinthal, Salzburg (A1,O,, 5°37 per cent) ; Mainland, Shetland Isles (AI,O,, 4:14 per cent); and Fahlun, Sweden (AI,O,, 4°69 per cent). No occurrence is mentioned by Hintze which like the Canaan mineral contains considerable amounts of both alumina and lime. As regards the color of the mineral, it seems to be altogether exceptional. Nearly all the text-books mention a rose tale from Cooptown in Harford County, Maryland, but I am informed by Dr. G. H. Williams that the authority for this is a state- ment made by Tyson as long ago as 1837, the mineral being not tale but kaemmererite or rhodochrome. Hintze mentions in his Handbueht+ beside the Cooptown locality, two others where rose-colored tale occurs, viz: in granite at Fischbach near Hirschberg, Silesia,t and with magnesite in clay slate at * Leipzig, 1892, pp. 824-6. + Loe. cit., pp. 819-821. ¢ Traube, Min. Schles., 1888, 224. NV. H. Darton—Magothy Formation of Maryland. 407 Wald in Styria.* The original reference to the first has not been accessible to me, and the second contains no mention of the mineral’s properties. The Canaan mineral is thus shown to belong to the tale family by its chemical composition as well as by most of its physical and optical properties. That it is a somewhat distinct variety is shown by its high percentages of lime and alumina, by its low fusibility and easy decomposability by acid, and by its exceptional rose color. University of Wisconsin. Art. L.—The Magothy Formation of Northeastern Mary- land; by N. H. Darton, U. S. Geological Survey. ConTENTS: Introductory. General relations. The Magothy Formation. Dis- tribution. General features. Hast of Chesapeake Bay. Magothy River region. Severn River region. Odenton region. Patuxent River region. Original extent and thickness. Definition. Synonomy. Economic Geology. History. Introductory. In this paper there is described an arenaceous formation not heretofore discriminated, lying between the Potomac and Severn formations in the upper Chesapeake Bay region. Up to 1891, when I published my memoir on the Mesozoic and Cenozoic formations of eastern Virginia and Maryland,+ I had given but little attention to the details of the geology of northeastern Maryland and believed that there was but one physical gap between the Potomac and Severn formations. Later studies in this region have led to the discovery that a series of sands and brown sandstones which I formerly sup- posed to be a local upper member of the Potomac formation, is separated from it by a continuous erosion plane, and consti- tutes a distinct formation. As this formation is excellently exposed on the Magothy River, and partly for want of a better name it has been desig- uated the Magothy formation. The general features of its dis- tribution in Maryland are shown on the accompanying map. In the course of a few weeks a geological map of Maryland will be published by the State on which tne lower boundary of this formation will be represented on a larger scale, and later its distribution west of Chesapeake Bay will be shown in detail on atlas sheets now in course of publication by the U. 8. * Rumpf, Ueber krystallisirte Magnesite aus den nordéstlichen Alpen, Tscher- mak’s Min. Mittheil., 1873, p. 271. + Geological Society of America, Bull., vol. ii, pp. 431-450, pl. 16. 408 N. H. Darton—Magothy Formation of Maryland. Geological Survey. Finally, I will describe the formation more fully in a Monograph on the Geology of the Chesapeake Bay region now in preparation. General Relutions. The coastal plain of eastern Maryland is underlain by a series of later Mesozoic to Pleistocene deposits lying on an east-sloping floor of crystalline rocks. These deposits are widely extended sheets of sands, clays, and marls inclined and thickening to the southeast and separated into formations by erosion breaks. In the following table there is given a list of these formations and breaks, an explanation of their age and a brief description of their general characters : Formation. Characters. Paleontologic position. 3 ( Columbia...- Loams, sands, and gravels. On g 4 terraces. 2 | Erosion interval. Development of = (\ outlines of present topography. .------- a ( Lafuyette.... Gravels, sands, and loams.- ---- Pliocene ? ore Erosion interval. Base levelling 3 4 over Coastal plain and westward ------ -—— < | Chesapeake...- Sands, clays, infusorial earths, [ and ‘mar lstieci set eaves Beye lepine Miocene. 3 Erosion interval, planing of sur- 8 faces} ol preceding, deposits 2-22 ss s4= =" aa S Pamunkey -..- Glauconitic marls and sands _. Eocene. ( Erosion interval, planing of surface of Severn and Potomac formations -~.-- ——— | Severn... Black, argillaceous sands, mainly-. Cretaceous. 5 Erosion interval, planing of surface = | of Magothy and Potomac formations... Cretaceous. & , Magothy.--- White sands and brown sand- o | Stones, also gravels 2-52.21. 22228 Cretaceour: ° Erosion interval, planing of surface of (Rotomac dormation==5-—" seen Cretaceous. | Potomac...- Clays and sands, also gravels and Karly N Sandstonesi-_ 22.25) 22 10.2 e es eee Cretaceous: Great erosional and stratigraphic break following Jura-Trias deposition. The Potomac formation lies directiy on the crystalline rocks and outcrops over a wide belt eastward. Its western border extends westward on the ridges and the crystalline rocks extend eastward in the intervening depressions. It is suc- ceeded eastward by the younger formations outcropping in succession in irregular northeast and southwest belts which are deflected westward of the ridges and eastward down the de- NV. H. Darton—Magothy Formation of Maryland. 409 pressions. The Lafayette and Chesapeake formations form a partial exception to this general statement for they overlap the other formations in some localities, and their western extension is now represented by small outliers occurring mainly in the higher lands to the northwest. The Columbia terraces extend across the other formations from the crystalline rocks in the depressions westward, to the Lafayette in the lowlands far to southeastward. In southern Maryland the typical Coastal Plain topography of the south Atlantic region prevails, an elevated east-sloping plain capped by Lafayette formation, and holding sharply depressed drainage basins lined with low Columbia terraces which extend eastward into a wide low belt adjoining the ocean. This east-sloping Lafayette plain has also a gradual tilt northward and with increasing altitude it is more and more widely eroded. Near the latitude of Washington it finally terminates, except for a few small outliers, and through north- eastern Maryland the region west of the bay, although still elevated, is rolling in contour in the higher lands and occupied by areas of Columbia terraces in the moderately elevated and low districts. The entire country east of Chesapeake Bay is a Columbia terrace relatively low throughout but gradually increasing in altitude to the north and northwest. MAGOTHY » i AND : ewe fees ASSOCIATED FORMATIONS soe oo IN Nortneastern MArYLano NH DARTON, Us. Gaolognal Survey Scale /6 miles az mck 4893 LEGEND Lafayette Chesapesko Pamunkey Serern Magoihy . FID Was Hincroni= . 2 3 ay Petomee 410 N. Hl. Darton—Magothy Formation of Maryland. The Magothy Formation. Distribution As is shown on the accompanying map the Magothy formation extends from the Delaware line to a point just southwest of Bowie, where it disappears in the overlap of the Severn onto the Potomac formation. I have not traced its eastward continuation through Delaware but the formation undoubtedly extends some distance at least, probably included in the sand marls described by Chester as the base of the glauconitic series. Kast of Chesapeake Bay the Magothy formation extends in a nearly straight line from near Chesapeake City to below Worten’s Point and outcrops below the Columbia deposits in the face of river and bay bluffs and in stream cuts. Its range of altitude is not great except in the outlying area of Maulden Mountain where it lies in greater part above one hundred feet above tide. Its dip is to the east-southeast at from 20 to 30 feet per mile. West of the bay the formation begins a short ways below Bodkin Point at the mouth of the Patapsco, and crosses the roll- ing country and three or four intersecting valleys, south-west- ward to its termination. Its inclination of from 30 to 40 feet per mile carries it far westward up the long slopes of the ridges in irregular sheets and outliers but it descends below the Severn formation at tide level eastward along a line essentially con- tinnous with its course on the eastern shore of the bay. The altitudes attained in the ridges westward are 130 feet on the neck between the Magothy and Patapsco Rivers, 240 feet in a far western outlier near Severn Station on the Magothby- Severn divide, 250 feet east of Odenton, 160 feet between the forks of the Patuxent and 190 feet on the ridge just east of Bowie. General Features.—The Magothy formation consists mainly of white and buff sands with local beds of brown sandstone, and limonitic streakings both in plates and discolorations. Southwestward it becomes gravelly for some distance and some portions are locally lithified into loose conglomerates or harder, more or less pebbly, brown sandstones. The ferrugination which gives rise to the brown sandstones is by no means con- fined in this region to the Magothy formation for brown sand- stone and limonitic masses and crusts are scattered locally in the Potomac, Pamunkey and Columbia formations and also but more rarely in the Severn, Chesapeake and Lafayette formations. The sands of the Magothy formation are mode- rately coarse and at some localities they are very coarse. They consist of quartz grains which vary in shape from rounded to subangular with a greater or less admixture of angular grains. SHAT, pute, Wile “A LYS, AK) f GAS AY NV. H. Darton—Magothy Formation of Maryland. 411 They lie loosely—a characteristic feature, in beds usually quite thin and regular but locally cross-bedded, sometimes to an extreme degree. The thickness varies from 10 to 30 feet but about 15 feet is the usual amount. An admixture of carbo- naceous materials is often present in the form of grains but several thin beds and interbeddings of lignite have been ob- served. A few thin streaks of pale gray clays occur interbed- ded in the formation in the Bohemia River region. The unconformities between the Magothy and Potomac below and with the Severn above are planes of erosion everywhere distinct and participating in the general southeastward inclina- tion of the Coastal plain deposits. East of Chesapeake Bay.—The northeasternmost exposures of the Magothy formation, which I have observed, are in the vicinity of Chesapeake City near the eastern terminus of the Chesapeake and Delaware canal. The cuts of the canal begin about two miles east of Chesapeake City and are in the marls and black sands of the Severn formation of which they afford a superb exposure. At the western end of these cuts and in several small stream depressions in the vicinity there are showings of the Magothy sands overlain by the black | Severn beds. The sands are white, gray, and buff, streaked irregularly with light brown. The entire thickness of the formation was not observed in this region but in one exposure twenty feet of its sands were seen, capped by weathered, gray- brown Severn beds along an undulating plane of unconformity. Between Chesapeake City and Bohemia Creek small expo- sures of Magothy beds are frequent in the deeper stream cuts. They are overlain directly by the Columbia gravels and loams westward, and the feather-edge of the Severn sands eastward. On the south shore of Bohemia Creek near its mouth there is a long, high bluff in which the Magothy and adjacent forma- tions are finely exposed. The basal beds are typical Potomac variegated clays, pink and red predominating, but in part buff and dark lead color. These clays extend to an altitude of about 30 feet at the western end of the bluff but this upper surface dips gently eastward and finally sinks below the water in about a mile. This upper surface is an undulating plane presenting no marked irregularities of contour and it is clearly a product of aqueous erosion. It is overlain by the Magothy sands which have a thickness varying from fifteen to twenty- five feet. These sands are mainly white or light gray but in places they are stained with buff and pinkish streak- ings. The materials are moderately coarse quartz grains quite uniform in size, rounded or subangular in greater part and lying loosely compacted in thin beds with but little cross-bedding. Near their base they sometimes contain a Am. Jour. Sci.—THirD Series, Vout. XLV, No. 269.—May, 1893. 412 NV. H. Darton—Magothy Formation of Maryland. small amount of clay fleckings and intermixture, derived from the subjacent clay formation, and discontinues streaks of limonite. Towards the western end of the bluffs they include two elongated lenses of tough, laminated, gray clay. The lower mass is near the base of the formation and is about six feet thick; the upper one is near the top and has a maxi- mum thickness of three feet. These clay streaks merge into the adjoining sands, but the transition is quite abrupt at most points. Overlying the Magothy formation eastward is a thin wedge of weathered Severn sands. separated by an east dipping erosion plane similar to the one below. The Severn beds attain a thickness of 15 feet at the eastern end of the bluffs but are cut out westward by an overlap of the overlying Columbia formation onto. the Magothy beds. The Severn beds are dark gray, argillaceous, carbonaceous, fine, laminated sands with some portions less argillaceous slightly glauconitic, more massive and lighter gray in eolor with buff mottlings. They are sharply contrasted from the Magothy beds and even without the separating unconformity could never be classed with them. The Columbia capping on these bluffs has a thickness of from four to seven feet. It consists of a basal bed of pebbles, bowlders and slabs with local beds of conglomerate and an upper bed of red-brown to buff, columnar loam with a few scattered pebbles. The next notable Magothy exposures southward are in the long high bluffs extending north from Grove Point. Towards the point the bluffs are of Severn beds overlain by Columbia deposits both superbly exposed.* About 1000 yards north of the point the Magothy formation comes up on a low southern dip and soon attains prominence in the bluffs in which it con- tinues to the end. The formation consists of coarse, loosely compacted, cross-bedded gray sands with irregular masses and streaks of brown sandstone and sandy limonite. The erosion plane separating the Severn formation is well exposed and is seen to be less regular in contour than usual. The ferrugina- tion of the Magothy beds is here very irregular and predomi- nates near the summit. Below are many scattered masses con- sisting of reticulated plates and tubes of sandy limonite, some of which are several feet in length and as much as a yard in thickness. On the peninsula between Elk River and the head of Chesa- peake Bay there is a high ridge on which there remains an outlier of Magothy with overlying Severn formation constitut- * Detailed descriptions of the Columbia formation in these and many other bluffs in this region are given by McGee in a memoir on ‘“ The Geology of the head of Chesapeake Bay. U.S. Geol. Survey, Seventh annual report of the Director, pp. 537-646, pls. 1888. Ff q . ; ; NV. H. Darton—Magothy Formation of Maryland. 413 ing two local eminences known as Mauiden Mountain and Bull Mountain. The western sides of these so-called mountains are cut by the bay giving rise to very prominent bare bluffs 120 to 130 feet in height, in which the Potomac and Magothy formations are well exposed. The Potomac beds in this region are the typical variegated clays in which pink and buff colors predominate but some reds and purples also occur. In the upper part of the Potomac here there is a local bed of white sand with more or less pink clay admixture which extends for some distance along the bluff. The Magothy beds lie on the usual erosion plane and are distinct from the Potomac sands and clays below. They consist mainly of coarse, loose, pure sands, regularly bedded except at a few points where cross-bedding was observed. Several thin, local streaks of clay are included and many large masses of brown sandstone. Loose masses of this sandstone, in part pebbly, are prominent in sandy areas between the higher portions of the ridge. The Severn outliers are of weathered beds, consisting of dark gray, fine, argillaceous sands below and more arenaceous, gray buff members above, attaining in all a thickness of about forty feet. Their entire separateness from the Magothy beds is exhibited in several exposures. The higher summits about Maulden Mountain are from 150 to 180 feet above tide level, and are capped by outliers of Columbia of the high level series. The high bluffs along the south shore of the Sassafras River near its mouth, expose the Severn beds in great force. Ap- proaching Howell’s Point the gentle southeast dip brings up the Magothy beds which soon displace the Severn formation, and extend westward nearly tothe Point. They are the usual moderately coarse sands but vary in color from pink to flesh col- ored in greater part, with light brown streakings locally. Their thickness is about twenty-five feet. They are loosely bedded, with some cross-bedding. The underlying Potomac beds come up in turn about 600 yards west of the first appearance of the Magothy beds and the two formations continue to the end of the bluffs, a short distance westward. The Potomac beds are typical variegated clays comprising white, buff, pink, red, and dark lead colors. Their surface is quite uneven and the clays are separated from the Magothy sands by a thin, interrupted, layer of impure limonite and coarse sand with a few scattered quartz pebbles. The bluff is capped with Columbia members which constitute about two-thirds of its height. Howell’s Point is a tide marsh area, but a short distance south the bluffs again extend to the bay‘shore and thence continue to Still Pond. The Columbia formation extends down to tide level for considerable distances in these bluffs but the upper part of the Magothy beds is well exposed in the 414 NV. H. Darton—Magothy Formation of Maryland. intervals. The formation consists of the usual coarse, loosely bedded sands generally white but in places stained buff or pinkish. Several short thin streaks of light colored clays occur and a few thin, discontinuous layers of ironstone. In the base of the overlying Columbia are several masses of coarse brown sandstones and conglomerate but they are sharply separated from the Magothy beds. Near the entrance to Still Pond a change of trend in the bluffs to southeast, carries them into the Severn belt, bringing in Severn beds between the Columbia and Magothy formations. In the next half mile the dip carries the Magothy formation below tide level and soon after, the Columbia deposits come down to the base of the bluff. The Severn beds in the exposure are weathered at their base to gray and lead colored clays with sandy layers; an unusual character. Higher up they are the typical black argillaceous, carbonaceous sands, covered superficially with green and gray sulphurous incrustations from decomposing pyrite, a common feature at this region. Their relations to the Magothy beds are particularly well exposed here and the gently undulating erosion plane extends along the bluff in plain view for a con- siderable distance. At their southeasternmost exposure in the bluff the Magothy sands are steeply crossbedded, some of the bedding planes having an inclination of 25°. South of Still Pond there are no notable exposures of Magothy beds, the prominent bluff on Worton Point lying west of their outcrop belt and exposing only Potomac and Columbia deposits. Magothy River region—The Magothy formation appears first on the western shore of Chesapeake Bay on the bay shore 14 miles south of Bodkin Point. The exposure is in a low bluff and consists of an irregular mass of brown sandstone in buff sands in all about fifteen feet thick of which the greater part is sandstone. It is underlain by typical yellow and pink Potomac clays along an irregular plane and dips below weath- ered, but unmistakeable Severn beds exposed a short distance south but not in contact. On the north side of the Magothy River the formation and its relations are well exposed in a small side inlet, Broad Creek, about three miles above the mouth of the river. To the east on Gibson, and Dobbin islands and in the adjoining higher lands notably Eagle Hill the Severn beds are extensively ex- posed with all their usual characteristics. To the west up the river the underlying Potomac clays and sands comes out. In the inlet above referred to the contact with the Potomac forma- tion is exhibited in a long low bank and the line of uncon- formity is seen to be unusually irregularly and strikingly dis- tinct. The Magothy beds are the usual coarse gray, loosely NV. H. Darton—Magothy Formation of Maryland. 415 bedded sands containing more or less brown sandstone. The Potomac formation here is a densely packed, moderately fine, “sharp” sand with more or less disseminated clay particles, a member which is first seen in this vicinity and extends for about twenty miles southwestward. This Potomac member merits some special description here on account of its unusual characters, relations to the Magothy formation and some mis- apprehensions which exist regarding it. Its sands grade into and give place to white and pink sandy clays at some localities but they are usually characterized by their purity and extreme compactness. At some points they are lithified in greater or less part into white or gray sandstones or quartzites, and less frequently brown sandstone. This sandstone constitutes the “White Rocks” out in the Patapsco River near its mouth and there are a number of other occurrences of it. ‘This arena- ceous Potomac member is, 1 suppose, the upper part of the ‘“‘ Albirupean formation ” of Uhler, but as it grades into typ- ical Potomac clays and sands and is unquestionably not sepa- rated by any stratigraphic break I see no grounds for its separa- tion as a distinct formation.* On the neck between the Magothy and Patapsco Rivers the sands and brown sandstones of the Magothy formation extend inland for several miles covering the higher areas and capping several small outlying knobs. Severn Liver region.—In the bluffs along the north shore of the Severn River at Round Bay and for some distance above, the Magothy formation and its relations are finely exposed. Just south of the Round Bay hotel there is a bluff which with the steep slopes above expose 140 feet of beds from the top of the Magothy some distance up into the Pamunkey formation. The Pamunkey beds here are weathered to brown, buff and red sands with ferruginated masses, containing Eocene fossils. Lying unconformably below the Pamunkey formation are 90 to 100 feet of the black micaceons, argillaceous and carbonaceous sands of the Severn formation. Near the base of the bluff the base of the Severn beds is exposed for several yards lying unconformably on very coarse, white Magothy sands along an east-dipping plane extending to a few feet above water level. In the next five hundred yards west these sands rise rapidly and some low bluffs exhibit a thickness of twelve feet with a *The term Albirupean was proposed by P. R. Uhler in 1888 to the American Philosophical Society (see Proceedings, vol. xxv, page 42). The fossils exhibited and reputed to have been obtained from the ‘‘ Albirupean” were shown by Heil- prin and Lewis to be of Upper Silurian age and were probably fragments from the Columbia formation. Its taxonomy was never clearly detined and its author now includes under the name the greater part of the upper Potomac formation of Maryland, all the sand lenses in the Potomac from top to bottom, apparently, and I take it, the great Potomac series in Virginia. 416 N. H. Darion—Magothy Formation of Maryland. thin capping of weathered Severn beds. The coarseness of the upper part of the Magothy is not so pronounced in this exposure and the sands for some distance below are of the usual moderately coarse, loosely bedded type. Near their base, thin, interbedded carbonaceous layers gradually come in and finally form an irregular lignitic layer with white sand streaks. Below this are irregular layers of brown sandstone two or three feet thick exposed along the beach. In the next bluff up the river, Potomac, Magothy and Severn beds are exposed in a section thirty feet in height. The Severn caps the bluff to a thickness of from six to nine feet and consists of fine, argillaceous sands weathered to a gray- buff color. They lie on a very even but clearly defined ero- sion plane exposed for nearly a hundred feet along the bluff, The Magothy beds average twenty feet in thickness but are several feet thicker at several points. They consist of regu- larly bedded, loosely compacted, gray sands with light buff streaks and blotchings containing thin streaks of brown sand- stone above, and large masses of brown sandstone below. They lie on a very uneven surface of the densely packed sands and clays which as before stated characterizes the upper part of the Potomae formation in this region. One of the most nota- ble irregularities of this surface is an old channel four or five feet in depth in which the Magothy beds come down nearly to water level. The Potomac deposits lying next below the Magothy formation are very densely packed, gray sands, in part lithified. They also contain a short streak of carbonaceous materials. Below, they give place abruptly to a series of lenses of very tough pearl-gray sulphurous clay with sulphur crusts on its surface. Underlying this clay are several] masses of sandstone which outcrop at the base of the bluff. A person unfamiliar with the complicated stratigraphic relations in the coastal plain formation would be puzzled by this exposure with its several exceptional features in the Potomac formation, and their apparent unconformities, and by the two horizons of brown sandstones. Ascending the river the dip brings up in succession lower and lower beds which exhibit very plainly the true general relations. There are several bluffs on the north shore exposing the very compact sands and clays of the Potomac, unconformably over- lain by the loosely bedded coarse, white Magothy sands here con- stituting the surface formation. In a bluff about a mile and a half above Round Bay the Potomac beds attain an elevation of twenty-two feet and are overlain by from eight to ten feet of Magothy sands. This exposure is the key to the horizon of the compact sands and gray sulphurous clays for they are finely exhibited, grading laterally and downward into looser white NV. H. Darton—Magothy Formation of Maryland. 417 sands with streaks of red and pink clay of the usual Potomac type. A short way west these sands are exceptionally pure and they are quarried for use in the arts but in the western part of the quarries and beyond they are seen to grade into variegated sandy clays and then pure clays of typical Potomac character. There can be no doubt of the Potomac age of these compact sands and clays lying immediately below the Magothy forma- tion in the district. North of the Severn River in this region the Magothy gray and buff sands with brown sandstone fragments cap the higher summits over a considerable area and at many points are seen lying on Potomac clays westward and the compact sand and clay member eastward. The northwesternmost Magothy expo- sure is a brown sandstone cap on a very small, shaly elevated knob a mile east by south from Severn station. On the south side of the Severn River the banks are lower and present no notable Magothy exposures. In the slopes south ascending westward nearly to Odenton there are fre- quent outcrops in which are seen gray and buff sands with brown sandstone masses. They lie on a gentle undulating plane of unconformity with local irregularities, and dip south- eastward at the usual rate of about thirty feet per mile. Odenton Region.—In the hills east of Odenton the Magothy beds attain an elevation of 220 feet and cap the higher lands over an irregular area of considerable extent. ‘They are over- lain by several small outlying areas of weathered Severn beds westward and the northwestern edge of this formation extends along the eastern slopes of the Magothy hills. In the southwestern extension of the Magothy formation the light colored sands, give place to darker colored and coarser sediments in which brown sandstones, gravels and conglome- rates prevail, The gravels are most conspicuous a mile and a half east of Odenton in the cuts of the Annapolis railroad, and on the adjoining hills. The relation to the Severn sands is plainly exposed in these cuts and at several points in stream and road cuts in their vicinity and southwestward. The gravels are more or less cemented into a loose conglomerate and inter- mixed with sand and brown sandstone. The aggregate thick- ness is variable but it amounts to 23 feet in the railroad cuts. Two and a half miles southeast of here towards Miilersville in the cuts for the Drum Point railroad a somewhat greater thick- ness is seen of buff sand, and brown sandstone, in part spar- ingly pebbly. Typical Potomac clays and sands are exposed underlying the Magothy formation at many points in the Odenton region and the usual unconformity is always very distinct. 418 NV. H. Darton—Magothy Formation of Maryland. Patuxent Liver region. — South of Odenton the Magothy formation gradually thins but it extends to some distance be- yond the Patuxent River before terminating. In the ridge just east of Bowie and again on the ridge be- tween the two forks of the Patuxent there are outliers of Magothy brown sandstones in turn capped by small areas of weathered Severn beds. The Potomac formation in the adja- cent slopes are typical variegated clays in greater part, but there are also lenses of compact gray sands locaily silicified to white quartzites. The southwestern termination of the Magothy formation is not clearly exposed and the outcrops along the Patuxent are obscure. In the hills southwest of Bowie the Severn beds lie directly on Potomac clays and are themselves cut out at intervals westward by Pamunkey beds as far south as Wash- ington. The thinning may be due to an actual decrease in thickness of the original deposit or an overlap of its shore lines by a later formation, but it appears to have resulted from an increase southward of the erosion to which its surface was subjected in the interval preceding Severn deposition. Original extent and thickness.—How far south the Magothy formation may have extended is not known, and as its surface has been eroded the original thickness is not determinable. The location of the northwestern shore line of the formation is not defined but it was probably very near the gravelly deposits extending from Bowie to beyond Odenton. Definition —The Magothy formation is a thin series of arenaceous deposits lying between the Potomac and Severn formations and separated from both by erosional unconformity and great dissimilarity of character. There are local uncon- formities at various horizons in the Potomac formation at the base of some of its sand lenses but these unconformities are due solely to current action and exist only within a restricted area. I have studied many of these Potomac sand lenses and found the sands grading laterally into clays or clays and sands and these merging downward across the horizon of uncon- formity into clays below. The unconformity at the base of the Magothy formation is clearly not of this character nor is the break at its summit, but both are in every way similar to the erosion planes which bound all the other members of the Coastal plain series. The age and equivalence of Magothy formation is not known with any degree of precision but its stratigraphic posi- tion places it in the early Cretaceous. It contains plant re- mains at several localities notably in the lignitic members on a NV. H. Darton—Magothy Formation of Maryland. 419 the Severn River at Round Bay, but they have not been studied. The formation is not divisible into individual members, for the variations in character which it presents are local features not characterizing definite horizons. Synonomy.—The Magothy formation has never before been discriminated or at least with any degree of definiteness. Mr. P. R. Uhler in his several papers* has referred more or less definitely to some of its features at several localities but he does not set forth its true relations.. He has separated a mem- ber, which he terms “alternate sand series” beginning some- where at this horizon and extending up into the Severn forma- tion, but its definition is so vague and moreover so variable in each succeeding publication of his that the name cannot be adopted without confusion. Economic geology.—The Magothy formation has not as yet yielded any great amount of economic products. Its sandstone members have been employed locally to some extent as build- ing stone and its gravels are used for railroad ballast. Some portions of its sands are, I believe, sufficiently pure for use in the arts notably on the Magothy River and at several points on the bay shore south of Howell’s Point. History.—The Magothy formation is a product of littoral deposition following the uplift and erosion of the Potomac deposits. It represents a time when currents and beach action were sufficiently active to sort out moderately coarse sands and spread them in beds, regular where the currents were gentle, and crossed where currents were more powerful. A few thin lenses of clay indicate that slack waters existed locally and the gravels westward indicate proximity to a shore line. The materials were probably all derived from the Potomac forma- tion and the shore line was located within the Potomac area throughout. The far eastward extension of the Magothy beds now deeply buried below the Severn deposits, undoubtedly consists of the finer sands and clays which were carried farther off shore before being deposited. Magothy deposition was succeeded by a general uplift and erosion interval during which the surface of the Magothy deposit was planed off in greater or less measure and degrada- tion of the Potomac surface westward was continued. This epoch was followed by Severn deposition. * Maryland Acad. Sci. Trans., vol. i, 1888-1892. 420 M. 1. Pupin—Electrical Oscillations of Art. LL—On Electrical Oscillations of Low Frequency and their Resonance; by M. I. Pupty, Ph.D., Columbia College. [Continued from page 334. ] Part IJ. THrorericat DIscussIoN WITH SPECIAL REFERENCE To THE TuHEorY or RISE oF PoTrENTIAL BY RESONANCE. I. Introduction. A very faithful mechanical picture of the periodically vary- ing flow in an electrical circuit possessing localized* capacity and self-induction is obtained by considering the motion of a torsional pendulum, that is a heavy bar, say of cylindrical form, suspended on a stiff elastic wire. The moment of inertia of the bar and the elasticity of the suspension wire correspond to the coefficient of self-induction and the capacity of the circuit. The frictional resistance of the air corresponds to ohmic re- sistance, internal friction in the bar and the elastic suspension correspond to magnetic and dielectric hysteresis ; angular dis- placement of the torsional pendulum corresponds to the elec- trical charge of the condenser, and therefore torsional reaction of the suspension to difference of potential between the con- denser plates. Angular velocity in the one case stands for the current in the other, kinetic energy for electrokinetic energy, potential energy of the torsional forces stands for the electro- static energy of the condenser charge. In slow mechanical vibrations the decremeut of the kinetic energy is chiefly due to external and internal frictional resist- ances. But as the frequency of the vibration increases other losses causing this decrement become more prominent ; so the losses due to radiation in form of sound waves. Similarly in electrical oscillations of very high frequency ; the decrement of the electrokinetic energy due to radiation in form of electro- magnetic waves becomes considerably larger than that due to dissipation in consequence of ohmic resistance, magnetic and dielectric hysteresis. The analogy, therefore, supplied by mechanical vibrations is by no means a poor guide in the study of even very rapid electrical oscillations. Hor slow vibrations the analogy is very striking and instructive. To return to the torsional pendulum :— Let I= moment of inertia of the bar, 6 = angle of displacement at any moment. *The term localized is employed to distinguish the circuits considered in this paper from those electrical circuits in which self-induction and capacity are more or less uniformly distributed over the whole circuit, as, for instance, in the case of a Herzian Resonator. Low Frequency and their Resonance. 421 Let the torsional force be as ordinarily assumed proportional to angle of displacement and the frictional resistance to angu- lar velocity. An impulse having set the pendulum in motion it is required to describe the motion. The differential equa- tion of motion is obtained by writing down the symbolical statement of the principle of moments, viz: Rate at which the moment of momen- ) Moment of all the tum about the line of pel eee = forces about the TTIPICIS cae pot op eee enc ieenis, She pea we epee same line. That is d/{_ dé do ——{ J — |= a— CLM ieinstrn teen oe Al A Cte (1) d’6 dé or Lae ge cae cee sieei tence (2) Certain well known conditions being fulfilled the following integral is readily obtained: a st 6 = Ae 21 sin ikl . (3) An 2.76. where T = natural period of the pendulum = Vio 4 ye eae The arbitrary constant A depends on the energy of the im- pulse and can be easily determined by well known rules. a 5 ‘ When ps small in comparison to T then that is, the natural period of the pendulum is independent of the frictional resistance. I venture to discuss briefly this rather familiar mechanical problem ; for, the discussion seems to throw a strong light upon some of the electrical problems which form the subject of this paper. Let T,= natural period calculated by (3) i 66 66 66 66 (4) By a simple transformation it is easily shown that 1 2 qs erent ee eh ano) 10 (5) 422 M. I. Pupin—Flectrical Oscillations of a where 7 = i a L = ratio (approx.) of frictional loss during any half period to the amplitude of the kinetic energy during the same half period. I shall call it the dissipation ratio. It follows therefore that whenever the dissipation ratio is smaller than + then T, differs from T, by less than #5 of one per cent. But since on the other hand It follows that when the dissipation ratio =4 then the pendulum will be practically reduced to rest after 16 com- plete oscillations. This simple calculation shows, therefore, that even in very damped oscillations the period can and in most cases will be practically independent of’ the frictional resistance. The following observations are too well understood to need a mathematical commentary :—a. If a periodically varying force is applied to a torsional pendulum the oscillations will be Sree oscillations if the period of the force is the same as the natural period of the pendulum, that is if the force and the pendulum are in resonance to each other. When this resonance does not exist the oscillations are forced. b. Of two periodically varying forces of the same mean intensity the one which is in resonance with the pendulum will produce the largest maximum elongation. The maximum elongation is reached when the work done by the resonant force during a complete period is equal to the frictional losses during that time. c. The torsional force of the suspension varies periodically, its period being the same as that of the impressed resonant force, but differing from it in phase by a quarter of a period. The amplitude of the torsional force can be much larger than the amplitude of the impressed force, especially when the frictional resistances are small, the moment of inertia large and the oscillations rapid, that is the torsional coefficient large. For in this case that part of the work of the impressed force which is stored up in the kinetic energy of the pendu- lum will become large before the maximum elongation has been reached. But since this large kinetic energy has to be stored up in the potential energy of the torsional forces once during each half oscillation it is evident that a large torsional force will be called into action. The amplitude of the tor- Low Frequency and their Resonance. 423 sional force is evidently an accumulative effect of the im- pressed force, and can easily be made so large as to break the suspension. This is a complete analogy to the breaking down of condensers due to a great rise in potential produced by resonance described further below. The analogy can be carried further by considering the mo- tion of a torsional pendulum A which is acted upon by a periodically varying force F,, not directly, but through another torsional pendulum B to which A is suitably connected. The study of the motion of this system under different conditions as regards resonance between A, B and F gives a complete mechanical picture of the electrical flow in an electrical system consisting of a primary and a secondary circuit, each circuit having localized self-induction and capacity, when a periodi- cally varying e. m. f. acts upon the primary circuit. An ana- lytical discussion of the motion of this mechanical system would lead far beyond the limits of this paper. It seems sufti- cient to point out, that the analysis is almost identical with the following mathematical discussion of the electrical flow in resonant circuits and that it is possible to imitate in a mechan- ical model most of the electrical effects discussed below, by properly constructed torsional pendulums connected to each other in a suitable manner. Il. On the Natural Period of an Electrical Circuit Possessing Localized Capacity and Self-induction. The cireuit consists of a coil, whose coefficient of self-indue- tion is L henrys, connected in series to a condenser of capacity C farads. Let the ohmic resistance be R ohms. An elec- trical impulse having started the electrical flow it is required to describe the flow. Let Q be the positive charge of the con- denser in coulombs, at any moment, then the differential equa- tion of the flow is obtained by writing down a symbolical ex- pression of the generalized form of Ohm’s law (disregarding losses due to magnetic and dielectric hysteresis) dQ aQi ‘ - FE) = =e tae HARA (ey) : AQ AQ VA tn Be or L qe t Bae +G@Q=0 ay MP one (22) Comparing these equations to (1) and (2) we see that certain well known conditions being fulfilled the familiar integral first discussed by Sir W. Thomson, can be written down as follows: 424 M. L. Pupin—Electrical Oscillations of R ome Qn Q= Ae sin=—t it where T = natural period of the cireuit a 27 i eee Bee TC Ge RF When — tT? is small in comparison tore G then tale that is the natural period of the circuit is independent of the ohmie resistance. To show that it is only under very exceptional circumstances that this condition is not fulfilled, I shall consider a circuit consisting of a large Bell telephone connected in series with a condenser of 1 microfarad capacity. The resistance of the telephone is 100 ohms, very large indeed, considering that its coefficient of self-induction is only about 0-5 henr ys. Making this circuit a part of the secondary circuit of the small trans- former excited by the electro-dynamic interrupter described in part I of this paper* it is found that the sound of the telephone is loudest when the frequency of the vibrator is about 225. The pitch of the sound is not sensibly altered by changing the resistance within very large limits; a result re- quired by theory. For the period calculated from formula T=27/LC gives 224,4 vibrations per second. Adding the correction given by formula (5) we get for the corrected period T,=224,9 a difference of only about + of one . eR Wcar : 1 per cent. Since the dissipation ratio Tainan We eee for the =) 2g damping factor ¢ ”?° 7 that is to say the electrical oscilla- tions would disappear almost completely after only 10 complete oscillations, which shows that the ohmic resistance produces a very strong damping and yet the period is practically inde- pendent of it. In circuits consisting of well made coils with finely divided but split iron cores the dissipation ratio 7 is very small even for frequencies as low as 100 periods per second. The period, therefore, will be independent of the dissipation losses even if * This Journal, April, 1893. Low Frequency and their Resonance. 425 hysteresis and Foucault current-losses approach the order of magnitude of the losses due to ohmic resistance. The natural period of such circuits, especially when tuned up to a fre- quency of over 200 periods per second will be given very accurately by the ae =274/LC Tr 0 such circuits only he Sollowing discussion refers. III. On the Electrical Flow in a Resonant Cireutt. Let a simple harmonic e. m. f. of period T act upon a cir- euit having localized self-induction and capacity, coil and con- denser being connected in series. By the generalized form of Ohm’s law we have in the usual notation Lo 4+Re+P=E sin pt (6) The integral obtained by well-known rules is pC sin ( pt— U ~ /Gap OL ap or i?) () _1—p’CL where tan eRe which can also be written = SS NAHAS Vp (pt+ P,) tan pe The integral written in this last form shows, as Oliver Heaviside first pointed out, that a condenser of capacity C in series with a coil changes the impedance of the circuit in such a way as if the ae had a negative coeflicient of self- induction equal to —~.* It produces also a shifting of phase. a The impedance is Pidineld to ohmic resistance when L,=0 or pLC=1, that is when the period of the impressed e. m. f. is equal to the natural period of the circuit, or in other words, when the two are in resonance. The current and therefore the amplitude of the charge of the condenser reach then their maximum value. *Tt is well to observe here that later on in the analysis of more complicated circuits possessing localized self-induction and capacity, I simplify my calculations 1 very much by substituting L; = uno for the coeffic. of self-induction and treating the circuit then as if it had no jeapacitys 426 M. I. Pupin—E£lectrical Oscillations of The resonant flow consists in a conversion of electrokinetic into electrostatic energy, and vice versa, during each semi- oscillation, accompanied by a loss due to ohmic resistance which is the only work which the e. m. f. does. The ampli- tudes of the electrokinetic and electrostatic energies must therefore be equal to each other, hence 4 (=) Seles G where P,= amplitude of the potential difference in the con- denser. The last relation gives, remembering that owing to resonance pLo=1, why 3 pls inductance Y (8) Sp CR Gs AR we Geavesistance If Land p are large and R small the rise in potential can be made as large as we please, or rather as large as the condenser will stand. The analogy between this rise of potential due to resonance and the torsional reaction of the suspension in the resonant swinging of the torsion pendulum mentioned above is striking. In both cases the reaction is produced by an accumulative effect of the impressed force. A rough experiment only, bearing on this point and which can be easily repeated in a few minutes in every electrical laboratory, will be briefly described here. Two large choking coils and a Marshall condenser were con- nected in series with the secondary of a transformer. The core of the smaller of the two choking coils consisted of a removable bundle of soft iron wire. The condenser terminals were con- nected to a Thomson Electrostatic Voltmeter. The frequency of the impressed e. m. f. was about 100 periods per second. The capacity of the condenser was adjusted until the removal of the plug was accompanied by bright snapping sparks, which was a signal that resonance was near. Then the removable iron core of the smaller choking coil was moved up and down grad- ually until the Voltmeter gave the largest deflection. A rise from 60 volts (generated in the secondary and indicated by a Cardew Voltmeter) to about 900 volts in the condenser was easily obtained. When the impressed e. m. f. was raised to 80 the condenser indicated about 1200 volts, which showed that the rise in the condenser was proportional to the impressed e. m. f., as the theory requires.* The rise of potential is practically * JT feel that itis only just to mention here that Mr. Marshall’s ordinary con- densers stood these voltages very well indeed, considering that they are guaran- teed to stand a 1000 volts as their upper limit. Low Frequency and their Resonance. ADT confined to the condenser, for the voltage on the line, indica- ted by the Cardew Voltmeter, does not change sensibly when resonance is established. There is a large and rapid change in the current with the approach of resonance which can be studied in a rough way by the pull which the choking coil exerts upon the removable iron core when the core is moved up and down during the process of tuning. The variation of this pull indicates very plainly that the curve expressing the relation between the current and the self-induction (resistance, capacity and frequency being constant), has a very steep crest which is in perfect accordance with the carefully plotted curve of equation (7) in Bedell and Crehore’s volume on alternating currents. * There are, however, several large maxima in this curve, each corresponding to a different capacity and self-induction ; the simple experiment just described shows their presence very forcibly. The maximum corresponding to the largest capacity with about the same self-induction being however consider- ably the highest. With the condensers that I had at my dis- posal at that time I did not dare to tune the circuit for the highest maximum. The existence of several maxima will be seen presently to be a necessary consequence of the theory. IV. Electrical Resonance in a Circuit with a Complex Harmonic Electromotive Loree. By Fourier’s theorem a complex harmonic alternating e. m. f, can always be represented by the following series: K=@, sin pt -- asin 2p... . a, sin npt . 9... oc = 2a da sin apt 1 In this expression I shall eall a, sin pt, a, sin 2 pt, .... the component harmonics, a, sin pt is the fundamental harmonic, its frequency, the fundamental frequency. The other harmon- ics will be referred to as the wpper harmonics. The order of magnitude of their amplitudes is @,> @,> d,>....>@n>.... The symbolical expression of Ohm’s law is this: dx e, ; L— + Re + P= 2a sin a pt dt 1 Comparing this to (6) it is seen from the integral in (7) that this differential equation has the following expression for its integral : * See Bedell and Crehore’s treatise: Alternating Currents, p. 138, published by W. J. Johnston Co., New York. Am. Jour. So1.—Tsirp SErizs, Vou. XLV, No. 269.—May, 1893. 30 428 M. L. Pupin—Eleetrical Oscillations of ee apCaa . A i — — = —sin (apt— 1 “V( a’p’ CL)? +a*p’COR Eee aha lai Where tan Qa ~~ apCR If we make 1—p*Cl=0, then the circuit is brought in resonance with the fundamental harmonic and the current is given by Or Zz ada = sin pt + 2a — R v 9 \/ pila?) aaa Re If the coefficient of self-induction is large then it is perfectly evident that the amplitude of the fundamental harmonie cur- rent is by far the largest especially when the frequency of the fundamental harmonic of the impressed e. m. f. is high. For instance, let i= 2, = 55 27, a V/ (a? — 3°)*p?L? + (3? R° f to take integral values from 1 to « except the value a. da R i sin a pt + sin (4p — pa) It is evident that now the fundamental harmonic with all the upper harmonics excepting the harmonic ais practically weeded out on account of the strengthening of the harmonic Low Frequency und their Resonance. 429 “ sinapt by resonance. The rise of potential according to formula (8) is given by apL = Rta: To show how this rise of potential compares to the rise ob- tained by resonance to the fundamental harmonic, let 4 = 5 and let the coefficient of self-induction be the same as before.* _ pl i R a, 5pL Paee tC de a Hence P. — Ba, It is a well known fact that well made alternators are con- structed in such a way that a, is generally larger than 5a,; hence, P, will be generally considerably larger than P, This was confirmed by the above experiment. (It is well to observe that this suggests a rather interesting method of analysing a complex harmonic e. m. f. into its com- ponent harmonies and of determining the relative value of the amplitude of each component.) The bearing of this on the method of producing a simple harmonic current by electrical resonance, described in the first part of this paper (1. ¢.) needs, I venture to say, no further dis- cussion. The study of resonance in electrical systems consisting of a primary and a secondary circuit with localized self-induction and capacity presents several features which deserve careful attention; a brief discussion of these together with a descrip- tion of several experiments bearing upon the theory of low frequency resonance will be given in my next paper. Electrical Engineering Laboratory, School of Mines, Columbia College, April 15th, 1893. [To be continued. ] *In the experiment described above the capacity was the principal variable ; for, the first approximation to resonance was obtained by plugging the condenser until the vicinity of resonance was reached. The maximum point was finally ob- tained by a, comparatively speaking, slight variation of the coefficient of self- induction. 430 Scientific Intelligence. SCIENTIFIC INTELLIGENCE. I. CHEMISTRY AND PHYSICS. 1. On the Properties of free Hydroxylamine.—A further paper on the properties of hydroxylamine has been published by Losry pE Bruyn. In the solid state it forms white inodorous scales or hard needles which melt at about 33°05° and remain in the surfused state on cooling, even at 0°. At 58° and under a pressure of 23™™, it boils; and when heated to 90°-100° it decomposes evolving gas. At a higher temperature it detonates. The crystals have a density of 1°35 as determined by the method of suspension in a mixture of chloroform and benzene; while in the liquid state the density is 1°23. According to Eykmann the refractive index at 14° for sodium light is 1°44128 and at 40° 143359. Its molecular mass by Raoult’s method is 33. The crystals liquefy on exposure to air, increase in weight and vola- tilize completely. In a current of dry chlorine, hydroxylamine inflames; but bromine and iodine decompose it without flame. In the solid state it is oxidized on exposure to the air; a white substance is formed containing nitrous acid and ammonia. When dry oxygen is passed through the fused hydroxylamine white fumes of nitrous acid are produced with but little evolution of heat. Sodium attacks it with the production of flame. When added to its solution in dry ether, hydrogen is evolved, and a voluminous white amorphous substance is formed probably a compound of hydroxylamine with sodium hydroxylaminate. Crystals of potassium permanganate, of chromic acid, of potassium and sodium chromates and of ammonium dichromate produce decomposition with a white flame; while potassium and sodium dichromates cause a sharp violent explosion. With certain chlorides, hydroxylamine forms compounds analogous to their hydrated salt. The most probable formula the author thinks is NH,.OH.—Rfee. Trav. Chim., xi, 18; J. Chem. Soc., \xii, 1391, Dec. 1892. . G. F. B, 2. On the Trisulphide and the Pentasulphide of Boron.— According to Moissan boron trisulphide may be formed (1) by acting on boron iodide with melted sulphur, (2) by acting on amorphous boron with the vapor of sulphur, (3) by the action of hydrogen sulphide on pure boron at a bright red heat, (4) by the action of pure carbon disulphide vapor on boron at a red heat, and (5) by the action of tin, antimony or arsenic sulphide on amorphous boron at a red heat. When condensed in a large receiver, boron trisulphide forms white slender needles which are very unstable and are decomposed by water with the evolution of hydrogen sulphide and without separation of sulphur. The crystals begin to melt at 310° and pass through a pasty condition. Their density is about 1°55. It is slightly soluble in phosphorus trichloride, from which it crystallizes in slender colorless needles. Chemistry and Physics. 431 Hydrogen does not reduce it at a red heat. It burns with a green flame in chlorine, forming boron and sulphur chlorides. Sodium and potassium decompose it below dull redness with incandescence. Water decomposes it violently, the reaction being B,S, + (H,0), = (B(OH,)), + (H,S),. Ammonia combines with it to form a yellow powder, evolving great heat. Organic compounds react energetically with it. Boron pentasulphide is a light white crystalline powder, fusing sharply at 390° and having a density of 1°85. It is best made by heating boron iodide with sulphur in a carbon disulphide solution for 24 hours at 60°. The precipitated product is washed with the disulphide to remove the iodine, with which it forms an additive compound. It is hydrolysed by water into boric acid, hydrogen sulphide and sulphur. When heated to its fusing point in a vacuum it dissociates into the trisulphide and sulphur, and is similarly decomposed when heated with mevcury or silver. —C. &., cxv, 208, 271; J. Chem. Soc., \xii, 1893, Dec. 1892. G. F. B. 3. On the Oxidation of Different forms of Carbon.—W1Es- NER has examined different varieties of carbon under the micro- scope while being subjected to the action of a mixture of sul- phuric acid and potassium dichromate. Charcoal obtained by heating soot in chlorine and hydrogen successively is rapidly attacked owing to its finely divided state. lLignite consists of brown transparent particles, becoming colorless by treatment leaving a skeleton of cellulose. Anthracite, bituminous coal, wood charcoal, soot and graphite, contain a small quantity of an easily oxidizable substance which is readily dissolved by the chromic solution, leaving a residue which is only very slowly attacked. The black lung pigment acts like soot and hence must be derived from the outer air—MWonatsb. xiii, 371; J. Chem. Soc., |xii, 1273, Nov. 1892. Gark. 1B; 4. On the Rise of Salt-solutions in Filter paper.—It was long ago observed by Schénbein that, when a piece of filter paper is immersed in a saline solution (1) the water rises more rapidly _than the dissolved salt and (2) the height to which the latter rises is different for different salts. So that by this means it is possible to recognize the different constituents of a complex so- lution. E. FiscurER and ScuMiIpMER have investigated this phe- nomenon more closely and have reached the conclusion that the result is due to the differences in the diffusibilities of the dissolved substances, that salt which has the greatest velocity of diffusion rising most rapidly in the paper. Hence diffusion phenomena can be studied in this way quite as well as by the use of mem- branes; the new method having the advantage that it is appli- cable to all liquids which moisten filter paper. The authors used in their experiments a glass tube 2 cm. in diameter and 70 cm. long, containing six rolls of filter paper, each about 10 cm. long and weighing about 7 grams. The paper had been purified by washing with hydrochloric and hydrofluoric acids and the rolls 432 Scientific Intelligence. were fitted rather tightly into this tube, so as to make good contact with the walls of the tube and with each other. The tube was then placed upright in the solution to be examined, its lower end being immersed two or three centimeters deep, and it was allowed to remain in this position until the fifth roll of paper was completely moistened by the rising liquid ; requiring from 3 to4days. To ascertain the composition of the liquids at the several levels, the tube was cut across opposite the ends of the adjoining rolls, and the rolls separately extracted with water. Using a solution containing 10 grams sodium chloride and 10 grams barium chloride in 100 ¢. c. water, the authors found the ratio of BaCl, to NaCl to be in the fifth roll 1: 1°364, in the third 1: 1:230 and in the first 1: 1:022; showing the greater diffusibility of the sodium chloride. With a solution of 10 grams erystallized ammonium-ferrous sulphate in 100 c¢. c. water, 87 hours were required to reach the sixth roll, and the ratio of the Fe to the NH,, which in the double salt is 1:1, was found to be in the 4th roll 1: 1686. When a saturated solution was used, the ratio in the fourth roll, after 96 hours, was only 1: 1:004, and in the fifth 1: 0°993. Potassium-ferrous sulphate and potassium- nickel sulphate gave similar results; a considerable dissociation taking place in dilute solutions, while in saturated solutions it is scarcely appreciable. Further experiments showed that aqueous solutions of the double chlorides of mercury with sodium and with lithium are decomposed by diffusion, while alcoholic solutions are not; and that the ammonium double chloride is permanent even in aqueous solution. No splitting was observed with the double salts HNa(NH,)PO,(H,0),, (KCy, AgCy), and KNaC,H,O, (H,O), in aqueous solution; but the compound of sodium chloride with grape sugar (C,H,,O,),NaCl is partially dissociated. No decomposition was observed with naphthalene picrate or methyl- ketol picrate. Making a comparative experiment with Riidorff’s apparatus, the authors found that though the dissociation was more effective in a given time with ammonium-ferrous sulphate and with the sodium chloride compound of grape sugar by the mem- brane diffusion method, the filter paper method was the better for . the sodium mercuric chloride.—Avnn. d. Chem., cclxxii, 156, 1892. G. F. B. 5. On Chemical Inactivity at low Temperatures.—Some in- structive experiments have been made by Raovt Pictet confirm- ing his view that all chemical action ceases at very low temperatures. Sulphuric acid solidifying at —56° and containing 89 per cent H,SO, was brought into intimate contact, in the solid condition and at a temperature —125°, with finely powdered sodium hydroxide, at the same temperature. No chemical action took place between them even when strongly compressed. Even when electric sparks were passed through the mass, no effeet was produced except in the line of the sparks. On warming to —80° action suddenly began, evolving great heat and fracturing the vessel. With a weaker acid containing 35 per cent H,SO, Chemistry and Physics. 433 solidifying at —88°, the results were similar. In like manner potassium hydroxide remains unacted on below —90°. Concen- trated ammonia and sulphuric acid do not act at all on each other below —80°; while above this temperature, a limited action takes place by means of electric sparks, complete reaction suddenly occurring at from —80° to —65°. Sulphuric acid does not react on common salt below —50°; though at about this temperature a lim- ited reaction begins which becomes complete at —25°. No action takes place between sulphuric acid of 35 per cent and sodium or calcium carbonates at —80°. Gas bubbles make their appearance first at —56° with sodium carbonate and at —52° with calcium carbonate; the reaction becoming turbulent at —15° with the lat- ter and at —30° with the former carbonate. With nitric acids chemical action begins at a slightly lower temperature. Me- tallic sodium undergoes no change when brought into contact with aqueous alcohol at —78° containing 84 per cent alcohol ; the action beginning only at —48° and then being active. Sodium may be mixed with 35 per cent H,SO, at —85° without any action; but at —50° a violent reaction occurs, the hydrogen taking fire. With potassium, the action begins at —68°. At — 85°, sulphuric acid may be mixed with an alcoholic solution of barium chloride without precipitation, the reaction first occurring at —70° and becoming complete at —40°. An alcohol solution of silver nitrate was mixed at —125° without reaction; precipitation beginning at —90° and being complete at —80°. Potassium hydroxide dissolved in alcohol was mixed with phenol-phthaleim at —135° without action; a faint red tinge appearing at —100° and the color being distinct at —80°. Litmus in contact with acids remains blue at —120°, a sudden change to red taking place with sulphuric acid at —105° and with hydrochloric acid at —110°. Hence the author concludes that no chemical action whatever takes place at temperatures between —125° and —155°.—C. R. exv, 708, 814; J. Chem. Soc., \xiv, 11, 112, March, 1893. «G. F. B. 6. Berzelius und Liebig, Ihre Briefe von 1831-1845. 279 pp., 8vo. Munich and Leipsic, 1893. (J. F. Leamann).—The cor- respondence of these illustrious chemists has been well edited by Justus Carriere; it is published under the auspices of the Royal Bavarian Academy of Sciences. The book gives fascinating glimpses of the personality of both these famous men—the fire and enthusiasm of the younger Liebig and the calmer sagacity of the Northern philosopher. The letters contain much that is of historical interest to the student of chemistry, in giving many descriptions of the experiments and discoveries of both these cele- brated investigators, many discussions of views and theories, and numerous criticisms of the work of other chemists of the time. The chief charm of the book, however, lies in the fact that the letters are given literally and in full, even where written in ex- citement and bitter animosity. These letters are supplemented by extracts from others between Liebig and WoOhler, so introduced as to give a most effective form of explanation. H, L. W. 434 Scientific Intelligence. 7. Carl Wilhelm Scheele—Briefe und Aufzeichnungen heraus- gegeben von A. KE. NoRDENSKIOLD. Roy. 8vo, 491 pp. Stockholm, 1892.—In thus preserving in permanent form and making public the scientific letters and laboratory notes of Scheele, Professor Nordenskidld has rendered a great and lasting service to the his- torical literature of science. ‘There seems to be a period of retro- spection in chemistry at present and a desire to place its historical foundations on a sure basis, and thus the appearance of this pub- lication is particularly opportune. Among the crowd of eager and gifted searchers of the last half of the previous century, with whom the modern era of chemical science began, no figure stands out more luminous or conspie- uous than that of Scheele. When we consider the particularly unfavorable conditions under which he worked, compared with the magnitude of the results he achieved, by the force of skill, energy and intellect, he must at once take place in the front rank of scientists of all ages. His claim to this position is materially strengthened by this publication of his notes and letters. To him must be ascribed the prior discovery of oxygen, chlorine, man- ganese, baryta, and many other discoveries which would have entitled a chemist to renown. Of particular importance were his researches in the line of organic chemistry, which are now for the first time fully set forth. - Itis certainly true, as Professor Nordenskiéld remarks, that these letters will be read with interest and pleasure by every chemist and thinker, engaged in original research. They are chiefly ad- dressed to Scheele’s friends, Retzius, Gahn and Bergmann. Besides the notes and letters which have been carefully turned into mod- ern German and are accompanied by critical notes, there is an able sketch of Scheele’s life and facsimiles of his writings. The volume is moreover a beautiful specimen of the typographical art. IGB W/o, 12% 8. Simple apparatus for measuring the Index of refraction of Liquids —H. Ruoss immerses a mirror vertically in the liquid, leaving a portion not immersed. The mirror can be turned about a verticalaxis. Atasuitable distance, about four meters, is placed a scale and telescope. The reflection of the scale in the air and in the liquid are then observed. One can make many observa- tions at different angles of refraction by turning the mirror. The mean error of a single determination of index of refraction of water at 22°9° C. with sodium light was 0:00011 to 0:00005.— Ann. der Physik und Chemie, No. 3, 1893, pp. 531-535. J. 'T. 9. Electromagnetic Theory of Color dispersion. —H. von Hetmuortz points out that no satisfactory explanation of color dispersion by the electromagnetic theory has been given. He accordingly submits the question to mathematical analysis, com- bining his own theories of electrically charged molecules with the general equations of Maxwell, and is led to a satisfactory explan- ation of the subject by means of the electromagnetic theory of light.— Ann. der Physik und Chemie, No. 3, 1893, pp. 389-405. Tues Chemistry and Phystes. 435 10. Penetration of thin metallic screens by Phosphorescent rays. —LENARD, at a recent meeting of the Berlin Academy, described some experiments upon this subject. Rays from an aluminum cathode disc were projected on a thin aluminum window 0:003™" thick. The cathode rays passed through the window and made the air faintly luminous. There was a strong smell of ozone. Other gases, besides air were tried. .Oxygen and carbonic acid were less penetrable than air. ‘“‘One may say that hy- drogen molecules cause less turbidity in the ether than those of oxygen and the latter less than those of carbonic acid.” — Nature, March 30, 1893. ie (it, 1l. Representation of Equipotential lines due to a current flow- ing through a metallic plate—K. Lommet, in a_ preliminary communication, has described a method of showing these equipo- tential lines. He now publishes photographs of these lines and gives an explanation of Hall’s phenomenon by means of these photographs. = =e ee XLITl. —Champlain (?) deposit of Piacceee belonging foe the Littoral Plain; by A. M. Epwarps. 3 XLIV.—Refraction of Light upon the Snow; by A. w. WHITNEY XLYV.—Value of the force exerted by a current of Hlectricity. a in a circular conductor on a unit magnetic pole at its center; ‘by 8. “—. MoRrmLAND.{ 20252592 4= a= eee eee ey XLVL—Cookeite from Paris and Hebron, Maine; by §. Le PENELEDD. 2a ee ee 2 SS ae ees XLVII —Mineralogical Notes ; by S. L. perce See XLVIII.—Influence ot Free Nitric Acid and Aqua ene ; on the Precipitation of Barium as Sulphate; by. PR. E. he IROWNING 2020 2 SS a ee ee 9)! XLIX.—Rose-colored Lime- and Alumina-bearing Variety . of Tale ;~by= W. ° He OBES, 222 =o ee See ) L.—The |] Magothy Formation of Northeastern Maryland; by Sat Wi Ge DaBron 2 220 eee eee ea tog LI.—Electrical Oscillations of Low Frequency and their Resonance ;“by Moi. Pupin 22 43 eee SCIENTIFIC INTELLIGENCE. Chemistry and Physies—Properties of free Hydroxylamine, L. DE BRUYN: Tri- sulphide and the Pentasulpiide of Boron, Moissan, 430.—Oxidation of Differ- ent forms of Carbon, WiesNER: Rise of Salt-solutions in Filter paper, EH. FIscHER and ScHMIDMER, 431.—Chemical Inactivity at low Temperatures, R, : Picret, 432.—Berzelius und Liebig, Ihre Briefe von 1831-1845, 433.—Carl Wilhelm’ Scheele, Briefe und Autzeichnungen herausgegeben von A. H. NORDENSKIOLD : Simple apparatus for measuring the Index of refraction o Liquids, H. Rcoss: Electromagnetic Theory of Color dispersion, H. vi HELMHOLTZ, 434.— Penetration of thin metallic sereens by Phosphorescent rays, LENARD: Representation of Equipotential lines due to a current flowing through a metallic plate, K. Lommet: Alternating Currents, F. Beppnn and A; C. CREHORE, 435.—Die pbysikalische Behandlung und die Messung hoher Temperaturen, C. Barus: Hilfsbuch fir die Ausfihrung elektrischer Mes- sungen, A, HrYDWEILLER: Practical Physics, R. T. GLAZEBROOK and W..N. SHaw: Elementary Treatise on Physics, ‘Experimental and mS Me ae : SON, ee Fonniotion on Staten tena A. HOLuIcK: Organization of the Fossil Plants’ the Coal-Measures, W. C. Witt AMSON, 437 Fossil Plants as Tests of Clim A. C. Sewarp: Flora Tertiaria Italica, A. MESCHINELIT and X. SQuinaBoL. 43 —Correlation of Early Cretaceous Floras in Canada and United States, ne : Dawson: New Teniopterid Fern and its Allies, D. Wxitr, 439.—Bryozoa « the Lower Silurian in Minnesota, E. O. ULRICH, 440.—Terti ty Moll Florida, W. H. Datu: Petrographische Untersuchungen an argenti Graniten, J. RomBrrG: Phonolite in Great Britain: Catalogue of At Localities of Minerals, EB. 8. Dana, 441.—Repertorium der Seb ist Krystallographischen Literatur, 1885-91, P. Gro, 442. Miscellaneous Scientific Intelligence—Hodgkins Fund Prizes: Mechani Earth’s Atmosphere, C. ABBE: Manual of Irrigation peewee son: Jean-Servais Stas, 442. Chas. D. Walcott, U.S. Geol. Survey. Tae ) y TENCE ee ee Se STEN By SOs Established by BENJAMIN SILLIMAN in 1818. THE met AMERICAN EDITORS JAMES D. ann EDWARD 8. DANA. ASSOCIATE EDITORS ~ alae _ Proressors JOSIAH P. COOKE, GEORGE L. GOODALE anp JOHN TROWBRIDGE, or Campripcr. ~ _ Prorzssors H. A. NEWTON anv A. -E. VERRILL, oF New Haven, . Proressor GEORGE F. BARKER, or Pumaputruta. THIRD SERIES. VOL. XLV._[WHOLE NUMBER, CXLV.] No. 270.—JUNE, 1893. NEW HAVEN, CONN: J.D. & E. 8. 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Heavy paper edition, 10 cents; bound im cloth, 20 cents. es MINERALS BOLEITE.. Southern California. I have purchased the specimens collected by him d this time and saved during several previous months. They were almost entirely obtained by working over the old dumps and he is very confident no more ill found. While no very large crystals were obtained this time, there were te number of ss ones, SO that I'can offer eye alee from 10e. upward. Dr. A EEO OTE, 1224-26-28 North sory ey Street, Philadelphi ’ hf, Aad, Sy AA CL f if THE AMERICAN JOURNAL OF SCIENCE [THIRD SERIES.| Art. LIL.—Electro-Chemical Hiffects due to Magnetization ; by GEoRGE OWEN Squisr, Ph.D., Lieut. U. S. Army. Introduction. THE influence of magnetism on chemical action was the subject of experiment by numerous investigators during the first half of the present century.* Up to 1847, we find, by no means, a uniformity of statement in regard to this subject, and secondary effects were often interpreted as a true chemical influence. Among the earlier writers who maintained that such an influence exists, may be mentioned Ritter, Schweigger, Dobreiner, Fresnel, and Ampére, while those of opposite view were Wartmann, Otto-Linné Erdmann, Berzelius, Robert Hunt and the Chevalier Nobili. Professor Remsen’s discovery in 1881, of the remarkable influence of magnetism on the deposition of copper from one of its solutions on an iron plate, again attracted attention to the subject, and since then considerable work has been done directly or indirectly bearing on the question. Among other experiments by Professor Remsent were the action in the magnetic field of copper on zine, silver on zine, copper on tin, and silver on iron, in all of which cases the magnet evidently exerted some influence. With copper sul- phate on an iron plate the effects were best exhibited, the copper being deposited in lines approximating to the equipo- tential lines of the magnet, and the outlines of the pole being distinctly marked by the absence of deposit. * Wartmann, Philosophical Magazine, III, xxx, p. 264, 1847. + American Chem. Jour., vol. iii, 157, vol. vi, 430. Science, vol. i, No. 2, 1883. AM. JouR. So1.—THIRD SERIES, VOL. XLV, No. 270.—JUNE, 1893. 31 S44 G. O. Squier—Llectro-Chemical Messrs. Nichols and Franklin* were the next to conduct experiments bearing on this subject. They found that finely divided iron, which has become “ passive” through the action of strong nitric acid, suddenly regains its activity when intro- duced in a magnetic field, and also that when one of the two electrodes immersed in any liquid capable of chemically act- ing upon them, is placed in a magnetic field, a new difference of potential is developed between them due to this magnetiza- tion. They ascribe these effects to electric currents in the liquid produced indirectly by the magnet, which currents go in the liquid from the magnetized to the neutral electrode. Professor Rowland and Dr. Louis Bell+ were the first to note the ‘‘ protective action” of points and ends of magnetic electrodes, and to give the exact mathematical theory of this action. Their results were directly opposite to those of Messrs. Nichols and Franklin, who found, as stated above, that points and ends of bars in a magnetic field acted like zines to the other portions, or were more easily dissolved by the liquid. The method of experiment adopted by Professor Rowland was to expose portions of bars of the magnetic metals placed in a magnetic field to reagents which would act upon them chemically, and study the changes in the electro-chemical nature of the exposed parts by fluctuations in a delicate galva- nometer connected with the two bars. Iron, nickel, and cobalt were experimented upon and nearly thirty reagents were examined in this manner. The results are summed up in the following statement: ‘“ When the magnetic metals are exposed to chemical action in a magnetic field, such action is decreased or arrested at any points where the rate of variation of the square of the magnetic force tends towards a maxi- mum.” Other investigations in this field are those of Andrews,} who employed iron and steel bars from eight to ten inches long with their ends immersed in various solutions, and one bar magnetized by means of a solenoid. The protective action was not noted, but, on the contrary, the magnetized bars acted as zines to the neutral bars, thus indicating that they were more easily attacked. Practically the same results were obtained by Dr. Theodor Gross;$ soft iron wires 8™ long, and 3™ in diameter coated with sealing wax, except at the ends, were exposed to variaus * This Journal, xxxi, 272, xxxiv, 419, xxxv, 290. + Philosophical Magazine, xxvi, 105. t Proceedings of the Royal Society, No. 44, pp. 152-168, and No. 46, pp. 176— 193. §$ Ueber eine neue Entstehungsweise galvanischer Stroéme durch Magnetismus, —Sitzungsberichte der Wiener Akademie, 1885, vol. xcii, ’85, p. 1373. Effects due to Magnetization. 445 liquids. When one electrode was magnetized a current was obtained going in the liquid from the magnetized electrode to the non-magnetized electrode. It thus appears that there is at least an apparent inconsist- ency between the protective results of Professor Rowland and Professor Remsen, and those of Nichols, Andrews, Gross and others, who find the more strongly magnetized parts of iron electrodes more easily attacked than the neutral parts, and it was with the object of endeavoring to reconcile these results, and of studying the exact nature of the influence exerted by the magnet, that the experiments recorded in this paper were undertaken. | Apparatus and Method of Investigation. The method of investigation was that adopted by Professor Rowland in his previous work on the subject, since its facility and delicacy permitted the effects of the magnet to be ob- served whenever there was the slightest action on the elec- trodes by the solution examined, and the investigation could thus be carried over a wide range of material. A large electromagnet was employed to furnish the magnetic field, and, at a distance sufficient to prevent any direct influ- ence due to the magnet, a delicate galvanometer of the Row- land type was set up. Small cells were made of iron elec- trodes of special forms, coated with sealing wax, except at certain parts, and immersed in a liquid capable of acting chem- ically on iron. The whole was contained in a 50° glass beaker, and when joined to the connecting wires of the distant galvanometer was firmly clamped between the poles of the electromagnet. In the course of the examination of a number of substances it was found necessary to use two galvanometers, one specially made by the University instrument maker and very sensitive, which was employed with acids which evolve hydrogen, the other much less sensitive was best suited to the violent “throws” with nitric acid and iron. The samples of iron used throughout the experiments were obtained from Carnegie, Phipps & Co. of Pittsburg, and were practically pure. In order to insure a uniform density of surface, the elec- trodes were turned from the same piece and polished equally with fine emery cloth. The magnet could be made or reversed at the galvanometer, and its strength varied at will by a non- inductive resistance. The electro-chemical effects due to the magnetic field could thus be studied with facility by the fluctuations of the galvanometer needle. The original dif- ference of potential which always existed between the elec- trodes was compensated by a fraction of a Daniell cell, so the 446 G. O. Squier—Llectro-Chemical effects of a variation of the magnetic field could be observed when no original current was passing between the electrodes. The standard cells were made with care, and under uniform treatment possessed at 20° C. an electromotive force of 1:105 volts. The connections with the compensating cireuit, which contained a finely divided bridge, were so arranged that from its readings the difference of potential between the distant electrodes became known at once without involving the resist- ance of the cell or of the galvanometer. ; Since quantitative measurements of the effects observed were desired, a preliminary step was to calibrate the electro- magnet for a given distance apart of the pole-pieces. The method employed was the well-known one of comparing the galvanometer deflections produced by a test-coil in the field with those of an Earth Inductor in series in the circuit. Since the effect of the sudden addition of a certain strength of field was wanted instead of its absolute value, the deflections with the test-coil were taken for simple “ make” or ‘“ break ” and not for reversed field, thus eliminating the residual magnetism of the pole-pieces. H ana d EL zane aon which @ and d’ represent the deflections due to the Inductor and test-coil respectively; H and H’ the earth’s field and the field to be measured; m and n’ the number of turns and a and q@’ the radii of the coils, the particular values were In the formula applicable, viz: nearly, in na = 2071659 °™ n'a’? = 6°78889 om d = 4:697 Distance between pole-pieces 3°5™. H’ = 1299-48 d’H, and as d’ varied from 1, to 16, the range of field employed was from 65 to 20,800 H. A curve was constructed so that from accurate ammeter readings in the field circuit, the strength in absolute measure could be read off at once. Experimental Results. Preliminary.—The first experiments were made with very dilute nitric acid and iron electrodes, one a circular disc of 5™™ radius, and the other a small wire 1° long and 1™™ in diameter turned to a sharp point at one end. The point was placed opposite the center of the disc, at a distance of 1™ from it, and the whole placed so that the cylindrical electrode coincided with the direction of the lines of force. When the minute point and the center of the disc were exposed to the epic Liffects due to Magnetization. 447 liquid, and the magnet excited, a momentary “throw” of the galvanometer was observed in the direction indicating the point as being protected or acting as the copper of the cell. When the pointed pole was slightly flattened at the end, and the insulation so cut away that the surfaces of exposure on the two electrodes were exactly the same, the throw of the galvanometer on making the field was very much diminished, although still perceptible, since the disposition of lines of force would still be very different over the two plane surfaces of exposure. With ball and point electrodes precisely similar phenomena were observed as with a disc and point, except to a less degree. The gradual reversal of the current shortly after exciting the field ; the independence of the throw of the direction of the current through the magnet; the disappearance of the throw when the nature of the magnetic field at the exposed parts became the same; and the effects of artificially stirring the liquid were observed exactly as described by Messrs. Rowland and Bell. In the course of a large number of preliminary experiments with nitric acid, it was soon observed that under certain condi- tions the effect of suddenly putting on the magnetic field, was to produce a less rapid deflection of the galvanometer in the opposite direction, or indicating the point as acting as a zinc. Plainly this irregular behavior, due to the magnet, required a more systematic study than it had yet received. It had been found that the reversal of the current which regularly fol- lowed the “protective throw” was decreased or destroyed by © anything which prevented free circulation in the liquid, and that an acidulated gelatine, which was allowed to harden around the poles, was best suited for this purpose. The great irregularity observed in any one experiment made it necessary to eliminate everything possible which might mask the true phenomenon, if any accurate comparisons were to be drawn between the effects observed in the different cases, accordingly a standard form of experiment was adopted which was care- fully repeated many times. The cell found best suited for this purpose was composed as follows : Discelectrode: diameter.) 02 Jn i aa Chickmesseee soe pe area Zon oimtrelectrodes totallencth sea claus seh ome diainme tery tite A oe aed adam lene.thivoli pointes 1h eas 52 Distance of point from center of dise....-. 10° ™ The same electrodes were used throughout any set of experi- ments, being carefully cleaned and polished each time. 448 G. O. Squier—Electro-Chemical With nitric acid the liquid was finally made up, as follows : Distilled water 20202) esse see 10 grams Hard gelatine 9 ies Suns USE Ne ose gram C. P. nitric acid (sp. gravity, 1°415), 0°533 grams — The gelatine and water were allowed to stand until the former had dissolved without the application of heat, when the acid was added, and the whole thoroughly mixed. Too strongly acidulated gelatine would not harden at all. In some cases, in order to protect the point from the begzn- ning, the electrodes, secured as usual at the ends of two small glass tubes containing the connecting wires, were firmly clamped in the proper position between the poles of the mag- net, and the magnetic field put on before the cell was com- pleted by pushing the beaker containing the solution up in position around the electrodes. With this cell a series of parallel experiments were conducted to obtain the variation of the effects with time, or the amount of iron salts present; the fluidity of the solution, and with constant and variable magnetic fields. A. Behavior of the cell with time, in the Earth’s field. The cell was placed entirely outside the magnetic field, and galvanometer readings taken at intervals of one minute for three hours. The curve fig. 1 (1) shows these results. Posi- tive ordinates indicate a current from the point to the dise, and negative ordinates the reverse current. Other experiments with fresh solutions, same electrodes, same exposed area, and every condition as nearly as possible the same, gave curves of practically the same character, and the one given is selected to illustrate. The curve indicates that the original current was to the point electrode, this gradually decreased due to polarization until after an hour and five minutes it reversed slightly, but again reversed thirty-five minutes later, and after a little more than two hours the deflection became perfectly constant, re- maining so indefinitely. The iron salts formed could not move with facility from the exposed surfaces through the hardened gelatine, and were easily outlined from their brown color, as the whole apparatus was placed in a strong light. B. In a uniform magnetic field. The cell was next placed in the magnetic field which was kept practically uniform (about 15,650 H) for three hours, and galvanometer readings taken as before. Ge OLY Wy yoo Oe fey Oss) Liffects due to Magnetization. 449 The electrodes were magnetized before being introduced into the solution, so as to protect the point from the begin- ning. In order to prevent the influence of the rise of temper- ature due to the heating of the field coils of the electromag- net, the whole cell was packed with cotton wool between the poles. As Gross and Andrews observed the temperature effect was small, the solution rising but 0:7° C. in half an hour. em || - el 2 50 SS Bar F109 15 20 2 30 35 90 45 58 SSE Jlhe FG ole: The curve fig. 1 (II) shows the result of these observations. It is seen that the original current was as before to the point electrode, and about the same in value. This reversed after forty-five minutes, and rapidly increased to approximately twice its original value at the end of one hour and twenty 450 G. O. Squier—Electro-Chemical minutes, and instead of again reversing, remained indefinitely with the point electrode as azine. The distribution of the iron salts in this case was quite unlike the former. Notwith- standing the gelatine, the powerful magnetization of the ex- posed point gradually drew the iron salts from the dise as fast as they were formed, and concentrated them symmetrically about the point, giving the solution in this region an almost black appearance. After waiting a sufficient time to be assured that further presence of iron salts would not effect the permanency of the existing electromotive force, the magnetic field was gradually decreased without ever breaking circuit, by increasing the liquid resistance in the field current. This change of resist- ance was necessarily made more or less suddenly, and the deflection experienced at each increase of resistance, a not very sudden throw toward reversal, in every respect the same as had been repeatedly observed in the preliminary experiments, and very different from the characteristic “ protective throw” which is always sudden and in one direction. . By simply varying the field current with care, as explained above, the deflection could be reversed again and again at will, and could also be held at the zero of the scale indicating no current at all, as long as desired. When once the field was entirely broken the iron salts were released from the control of the exposed pole, seriously disturbed by gravity, and put- ting on the field again failed to reproduce the results noted above. The only elements of difference in the two eases are, (@) the magnetized condition of the metal, (>) the distribution of the iron salts formed by the reaction. Although, as the curves indicate, the average electromotive force with the magnetic field was much greater than in the former case, yet this electromotive force is due to the differ- ence of action at the two exposed surfaces, and, as will be pointed out later, the total amount of iron dissolved and passing into solution in the two cases is probably not very dif- ferent.* Quantitative experiments are wanting on this point. The influence of the magnetized condition of the metal and its magnitude is exhibited in the phenomenon of the “ protec- tive throw”? which is always observed with apparatus suffi- ciently delicate and unless it is masked by other secondary phenomena. Since the electrodes were embedded in hardened gelatine, there could be no convection currents in the liquid and this can be eliminated. Evidently the great difference in the * Fossati, Bolletino dell’ Elettricista, 1890. i Liffects due to Magnetization. 451 behavior of the cell in the two experiments described is prin- — cipally due, either directly or indirectly, to the distribution of the iron salts formed by the reaction in the two cases. The principal ¢2me effects of the magnet were: (a) To produce a higher potential at the point of greater magnet- ization. (6) ‘To increase the rate of change of the potential between the electrodes and the absolute value of this potential difference. (c) It also appears from both curves that after a certain distribu- tion of iron salts is reached, further presence of the same does not effect the permanency of the current established. Since the time effects of the magnet were so marked, it was thought possible that a “ cumulative ” effect, due to the Karth’s field alone might be detected after a sufficient time had elapsed. The apparatus was made as delicate as possible, and parallel ex- periments conducted, the electrodes first being placed in the magnetic meridian, and afterwards perpendicular thereto. No positive difference could be detected. C. Convection currents in the liquid. As has already been stated, the reversal of the current which regularly followed the ‘protective throw” was found by Messrs. Rowland and Bell to wholly disappear when hardened acidulated gelatine was substituted for the dilute acid solution, so that when the magnet was put on, a permanent deflection of much less magnitude was obtained instead of a transitory throw. This indicated that currents in the liquid cannot be neglected, and their study was next undertaken. Since hard- ened gelatine completely prevented the reversal of the current, and with no gelatine it regularly appeared after a short time, a large number of experiments were made, in which the amount of gelatine was varied continuously between these limits. As expected the effects also varied, the greater the fluidity of the solution, the more quickly the reversal occurred. In the light of what was already known concerning the presence of iron salts, some of the experiments were continued over a considerable time, and in others iron salts were intro- duced artificially, to increase the effects. It was soon found that by starting with a fresh hardened gelatine, with which the “protective throw” was the only feature, and gradually increasing the fluidity of the solution and the amount of iron salts present, both effects were exhibited at the making of the field, first, the sudden throw of the needle always in the direc- tion to protect the point, and immediately thereafter the com- paratively slow “concentration throw” in the opposite direc- 452 G. O. Squier—Llectro-Chemical tion. by making the conditions still more unfavorable for the ‘protective throw,” it gradually diminished until entirely masked by the second effect, so that making the field produced a deflection in the direction indicating a current from the point. With the proper conditions both of these effects could be studied with the greatest ease: first, one made prominent, then both equal, then the other made prominent at will. The “ pro- tective throw ” could be traced until it became a mere sta- tionary tremor of the needle at the instant of its starting on the “concentration throw.” This latter, though called a “throw,” can be made to vary from an extremely slow continu- ous movement of the galvanometer deflection, as in experiment B, already described, to a comparatively rapid detiection at the instant of making the magnet. By using simply a dilute nitric acid solution with no gelatine, and inserting a thick piece of glass between the electrodes, the concentration effect was delayed enough to allow the “ protec- tive throw ” to first appear, with considerable iron salts in the solution, and on making the field both effects were observed as described above. It now appears that the reversal of the current uniformly observed in the experiments of Messrs. Rowland and Bell was but a form of the “concentration throw” mentioned above, and that we can regard the substitution of the hardened acidu- lated gelatine for the dilute acid, as merely separating these effects, so that the former can be studied by itself; in other words, the reversal of the current would have occurred just the same after a sufficient time had elapsed. Turning to the experiments of Drs. Gross and Andrews, they employed but one magnetized electrode which was not pointed. In this case the nature of the magnetic field at the two exposed surfaces would be very much more nearly the same than when a pointed electrode is employed. This arrange- ment is not therefore suited to bring out the delicate ‘“ protec- tive throw,” and it is not surprising that the concentration effect was the prominent feature observed. We have now a complete reconciliation of the dzrectly op- posite results referred to in the introduction. The “ protec- tive throw” is due to the actual attraction of the magnet for the iron, and is always in the direction to protect the more strongly magnetized parts, while the “concentration throw ” is always in the opposite direction, and depends upon the dis- tribution of the iron salts present in the solution, and the con- vection currents in the liquid. The concentration of the products of the reaction about the point, would tend to pro- duce a ferrous reaction instead of a ferric reaction, and experi- iffects due to Magnetization. 458 ment shows that a higher electromotive force is obtained with cells in which a ferrous reaction takes place than with those in which a ferric reaction occurs, and this change in the character of the reaction produced by the concentration probably accounts, at least in part, for the increased electromotive force at the point. D. The iron salts about the point electrode. The effect of artificially stirring the liquid, and the direct influence of the fluid condition of the solution on the deflec- tions observed, at once suggested movements of the liquid, produced indirectly by the magnet. In order to locate these currents, and determine their potence, a small cell was made otf two rectangular pieces of glass held by stout rubber bands to thick rubber sides. Perforations in the sides admitted the electrodes which were point and dise as before. The cell, between the poles of the electromagnet, was in a strong light, and the movements in the liquid were easily perceptible from the displacements of suspended particles introduced for the purpose. When very dilute nitric acid was placed in the cell, and the magnet excited, some interesting phenomena were observed. The liquid, at first colorless, almost immediately assumed a pale brown color about the point, but nothing appeared at the dise electrode. The iron salts were drawn as soon as formed towards the point electrode, since here the rate of variation of the square of the magnetic force is a maximum. As more iron was dissolved, a surface approximating to an equipotential surface of the pointed pole, and enveloping the colored iron salts, was observed enclosing the point, and at some distance from it. The outline of the surface became darker in a short time, and finally two or more dark contours, separated by lighter portions and symmetrical with the outer one, appeared between it and the point, indicating maxima and minima of density. When the magnetic field was gradually increased, this surface usually enlarged without breaking up and holding the iron salts within it. On further strengthen- ing the magnetic field to about 16,000 H the ridges merged into one thick black envelope around the point. This phenomenon is best studied with but little iron salts present, and by watching the point electrode with a microscope while the strength of the magnetic field is increased and de- creased continuously. The sections, fig. 3 (p. 449), show the general form of these contours with different strengths of field. Upon breaking the field, everything dropped from the point suddenly to the bottom of the cell, and on making the field again, it required a few seconds for the salts to reappear at the 454 G. O. Squier—Electro-Chemical point. This, at least partially, accounted for the sudden effects often noticed at breaking the field circuit, and the compara- tively small ones at ‘make ” especially with certain salt solu- tions, such as copper sulphate. The outer envelope which held the iron salts together, and limited the immediate influence of the magnetized point, was distinctly defined within the liquid, and easily observed by the reflection of the light from its convex surface. The persistency with which the iron salts were held about the point was shown by moving the cell with respect to the electrodes, when the contour remained approximately intact, ° passing bodily through the liquid without being broken up. FE. Electromagnetic rotations. The small dust particles present in the liquid were drawn radially toward the point until they reached the surface de- scribed, when they pierced it and began to revolve rapidly about the point inside this surface, in the opposite direction to the currents of Ampere. Reversing the poles of the magnet, produced surfaces of the same appearance, but opposite rota- tions. When the current from a Daniell cell was sent through, it seemed to have very little effect upon the rotations, showing them to be controlled by the powerfully magnetized point. The electromagnet was arranged with its field vertical, and the point electrode along the lines of force as before. This arrangement gave better control of the surfaces formed, since gravity now acted symmetrically about the point. When a single iron rod about 3™™ in diameter, and placed vertically in the cell, was substituted for the two electrodes, two rotations were observed, which were uniformly dextro about the north-seeking pole of the rod, and levo about the south-seeking pole. About the central neutral portion no rota- tions were observed. When the rod was covered with a thin coating of vaseline, the rotations entirely disappeared as ex- pected. Wartmann* observed similar rotations about soft iron cylinders adhered to the poles of a magnet, and he ascribed them to electric currents in the liquid which proceed from the periphery of the cell radially to the surface of the rod. The explanation of these rotations follows at once from what we know of the time effects produced by the magnet. A higher potential is always produced at points of greater magnetization, causing electric currents in the liquid from the more strongly magnetized to the weaker parts of the iron. * Philosophical Magazine, xxx, 1847, p. 268. Liffects due to Magnetization. 455 Applying this fact to the exposed conical point electrode, we see that local electric currents exist from its vertex to the other parts of the surface, returning by way of the metal. In the case of the vertical rod, these currents pass from the poles at its ends, through the liquid, to the neutral portions, returning as before. These currents* under the influence of the poles themselves, would cause electromagnetic rotations of the liquid, as we find them. The mere mechanical influence of these rotations, as in the case when the liquid is artificially stirred, is to increase the chemical action upon the point, causing it to tend to act more like a zine. F. Acids which attack iron with the evolution of Hydrogen. Professor Rowland had observed the ‘“ protective throw” with such acids to be extremely small and difficult to detect, except by very sensitive apparatus. The sensitive galvanom- eter was set up, and every precaution taken against inductive effects. A telescope and scale were used in this part of the work. Several substances were first examined, among them being hydrochlorie acid, acetic acid, perchloric acid, chlorine water, copper sulphate, ferric chloride, sulphuric acid, etc., but as these observations added nothing to the results already ob- tained, they are not given here. After several trials a standard sulphuric acid solution was made up as follows: Distillediwater aes ts 5-546 ee se eee Ovorams Gelatin@yesss eye esis hae ou ently 1 gram C. P. Sulph. acid (sp. gravity 1°826)_..1:062 grams More strongly acidulated gelatine would not harden, and weaker solutions gave too small effects. The “protective throw” was detected, but the point very soon became completely covered with minute bubbles of hydrogen, so that the electrodes had to be cleaned constantly. The effect of adding hydrogen dioxide to the solution was next tried, since this would facilitate the removal of the hydro- gen as soon as formed,t which was thought to act merely mechanically. When about 1° of H,O, was added to the solution, the “»rotective throw” became much more prominent, and the * The rotations produced in liquids by axial currents, e. g. currents coinciding with the direction of the magnetic lines of force as distinct from radial currents, have been studied by Dr. Gore, Proceedings of the Royal Society, xxxuii, p. 151. + J. M. Weeren, Berichte der Deutschen Chemischen Gesellschaft, No. 11, 1891. 456 G. O. Squer—Electro-Chemical gas bubbles only appeared in small quantities after a consider- able time, further addition of small quantities of the dioxide showed the ‘ protective throw” to be very decided with sul- phuric acid when the hydrogen is removed from the surface of the electrodes in this manner. G,. The electromotive force. Several attempts were made to obtain the relation between the strength of field and the electromotive force developed in the “ protective throw,” but it was difficult to obtain consistent readings owing to the trouble of balancing the original deflec- tion, and the small absolute values of this electromotive force when hardened gelatine was employed. A curve was constructed, however, showing the variation of the galvanometer deflection with the strength of field, using nitric acid solution without gelatine. This is shown in fig. 2, p-. 449. The readings were taken one after another, as rapidly as possible, to eliminate the damping effects of the iron salts formed. The curve exhibits the general character of the variation. In the region from about 8,500 H to 8,000 H the greatest rate of change occurred, and beyond 10,000 H the curve became nearly horizontal for the particular electrodes used. Curves were also constructed for the “concentration throw ” on mak- ing the field under different conditions, and they were approxi- mately right lines more or less inclined, according to the amount of iron salts present. With the sulphuric acid solution already given, the electro- motive force varied from 0:0033 to 0°0078 of a volt, while with the nitric acid solution it became as great as 0:036 of a volt. In making all the solutions used with the different substances, amounts were taken proportional to their particular molecular weiohts. and then halved or doubled until of a suitable strength to give results with the galvanometer. It was thought possible at the beginning, that this might lead to some relations between the protective results and the strengths of the particular soln- tions, but the general irregular character of the whole phe- nomenon prevented comparisons in this respect, and all that can be stated is, that both the “ protective throw” and the con- centration effect, in general, increased rapidly with the strength of the solution. H. Influence of a periodic magnetic field upon the cell. An experiment was made to determine the behavior of the standard nitric acid cell when the magnetic field was made and Effects due to Magnetization. 457 broken at regular intervals over a considerable time, and curves were drawn showing the variation of the “throw > with time, and the fluctuation of the original deflection caused by this treatment. The strength of field was about 11,000 H, and the experiment was conducted without compensating the original deflection, and by making the field for one minute, then break- ing for one minute, and so on. One of the curves is shown in fig. 1, (III) in which positive ordinates are values of the concentration throw at ‘‘ make,” and negative ordinates the values of the “ protective throw.” Experimenting was not begun until the gelatine had com- pletely hardened, and since the electrodes would tend to become polarized while the gelatine was hardening, the “ protective throw” was very small, and soon masked by the concentration effects. After about five minutes, making the field had very little effect at all, but began to show decided “ concentration throws” ten minutes later, and these rapidly increased with time, as the curve indicates. Considering the fluctuation of the original deflection, the effect of this periodic field was to tend to reverse it, just as in the case of the uniform field in experiment B, but much more slowly, since the field was on but half the time in this case. The cell also showed the iron salts almost entirely about the point, forming a thick black envelope. I. Summary.—The principal results of this investigation may be summarized as follows: Whenever iron is exposed to chemical action in a magnetic field, there are two directly opposite influences exerted. (a) The direct influence of the magnetized condition of the metal, causing the more strongly magnetized parts to be pro- tected from chemical action. This is exhibited in the phenomenon of the “ protective throw ” which is always in the direction to protect the more strongly magnetized parts of magnetic electrodes. The “ pro- tective throw ” is small, often requiring delicate apparatus to detect it, and is soon masked by the secondary concentration effects. As to the absence of the “protective throw” with acids which attack iron with the evolution of hydrogen, the hydro- gen acts merely mechanically, and when removed by adding to the solution small quantities of hydrogen dioxide, the ‘ pro- tective throw” becomes very decided. In the curve, fig. 2 (p. 449), representing the variations of the “protective throw” with the strength of the magnetic field, we trace at once the magnetization of ‘the point electrode. Since only the minute point was exposed to the liquid, it would 458 G. O. Squer—Electro-Chemical Liffects, etc. become saturated for comparatively small magnetizing forces, and the curve indicates that this occurred at about 10,000 H, beyond which the curve becomes practically horizontal. This further establishes the direct connection between this “throw ” and the variation of the magnetization of the exposed point, and confirms the explanation of Professor Rowland, that it is due to the actual attraction of the magnet for iron, and not to any molecular,change produced by magnetization. (0) The indirect influence of the magnet caused by the con- centration of the products of the reaction about the more strongly magnetized parts of the iron. This tends to produce a higher potential at the more strongly magnetized parts, and finally establishes permanent electric currents, which go in the liquid from the more strongly mag- netized to the neutral parts of the iron. This concentration effect increases rapidly with the amount of iron salts present and the fluidity of the solution. The convection currents in the liquid are themselves a con- sequence of this same concentration, being electromagnetic rotations produced by the action of the magnet upon the local electric currents between different parts of the iron. As to the permanent current, due to the magnet which is finally set up between the electrodes as shown in fig. 1 (ID), it is probably due to a change in the character of the reaction produced by the concentration of the iron salts about the more strongly magnetized parts, which would tend to cause a ferrous instead of a ferric reaction to take place, and thus increase the electromotive force. Physical Laboratory, Johns Hopkins University, May, 1892. Note.—Since the completion of the above investigation, a number of experiments have been performed similar to those of Professor Remsen. Starting with the known existence and direction of the electric currents in the liquid, it was thought that these might lead to some explanation of the peculiar form of deposit in equipotential lines. A number of interesting facts have been noted, but they are withheld for further ex- periment. G. 0. (S: Nitikin on the Quaternary Deposits of Russia, ete. 459 Arr. LIL.—Wtkitin on the Quaternary Deposits of Lus- sia and their relations to Prehistoric Man; by A. A. W RIGHT. AT the international Congress of archeeology in Moscow, in 1892, the Russian geologist, Mr. S. Nikitin, presented an elaborate paper upon the above subject. A summary of his views will be of interest in connection with the pending dis- cussion upon the continuity of the Glacial epoch. The paper opens as follows: ‘The terms ‘Quaternary Period’ or ‘ Post- tertiary’ with their subdivisions and geological equivalence in the series of deposits, are far from being definitely settled by science. At the latest sessions of the International Geological Congress at London and Washington there was much debate upon these questions without arriving at any definite results.” It will be recalled by those present at the Washington ses- sion that two distinet glacial epochs in Germany were argued for by Dr. Wahnschaffe,* and similarly by Baron De Geer for . Sweden. On the other hand Professor Credner thought that the stratified beds between deposits of till were only local, indicating some retreat and re-advance of the ice-sheet, but no interglacial epoch. Dr. Carl Diener suggested that intercala- ted beds of sand were no positive proof of interglacial epochs, as moraines, in the Austrian Alps, no more than twenty years oid, were covered with pasture. Dr. Holst of Sweden, men- tioned two moraines separated by interpolated sand, and thought that they might both have been formed by the same ice-sheet. A blue ground-moraine and a yellow upper-moraine were deposited even in northern Sweden, where there is no indica- tion of the retreat of the ice. Professor Hughes of Cambridge, expressed his opinion that the Ice age was a single continuous cold period, in England at least, except for slight and unim- portant oscillations in the extent of the ice-sheet. Mr. Nikitin continues: “I do not pretend to solve this complicated question ; but will confine myself to giving a brief analysis of the signification and the meaning which I attribute to this terminology. Under the name of Quaternary period or Post-tertiary I include all the time since the close of the Pliocene up to our day. I divide this period into two epochs, the Pleistocene (earlier) and the modern epoch. The close of the Pleistocene is characterized, as I conceive, by the disap- pearance of the mammoth, the rhinoceros, and other large mammals which are now wanting within the limits of Russia. This subdivision coincides with that of many archeologists * Am. Geol., viii, 241. Am. Jour. Sc1.—THirp SERIES, VOL. XLV, No. 270.—Junz, 1893. 32 460 Nitikin on the Quaternary Deposits 0f Russia Y Le} that is to say, with the subdivision into the palwolithic and neolithic epochs... . . I think that this subdivision will stand, even though, along with the remains of the mammoth, there should be found some polished stones as the first indications of a more perfect industry.” .. .”: ‘“‘ As to the time of the disappearance of the mammoth. . it is certain that wherever the glacial deposits are developed in their entirety, the remains of the mammoth are not found above the morainic deposits of the so-called second glaciation ; or at least they are very rare. The time of the greatest development of the mammoth and rhinoceros in Europe corresponds to the period called interglacial, and to the second glaciation of northern Europe. In northern and central Russia, which ex- hibits everywhere but a single moraine, the remains of the mammoth and rhinoceros are found principally in loessiform deposits, in old lake and river deposits covering the moraine, or the products of its alteration. These facts prove that the, morainic deposits of Russia belong to the first glaciation, and that by analogy with the west our loess, and the ancient allu- viums where the remains of the mammoth and rhinoceros are found, are sediments corresponding to the interglacial epoch, and the second glaciation.” “There are two questions whose solution is important for the subject of which Iam treating: first, that of two glaciations in middle Europe, and then, that of the so-called interglacial deposits of Germany, England and Scandinavia. You know, gentlemen, that the idea of two epochs of glaciation (and even of several, according to some investigations) has been suggested by the discovery, upon the great expanse of the countries mentioned, of two morainic deposits, separated by heavy, strat- ified beds, in which are occasionally found numerous traces of the Pleistocene fauna and flora. At the same time, the parti- sans of this theory affirm that the second glaciation was less powerful than the first, and that it could not cover all the region occupied by the primary and principal glaciation. You know also, gentlemen, that this theory, adopted by the larger number of those who have studied the Quaternary deposits, is far from being irrefutable. I will remark in the first place, that the supposition of three and even four distinct glaciations instead of two, indicates the possibility of diverse explanations, and diverse opinions upon the genesis of these interglacial deposits. For several countries, there has recently been demonstrated the weakness of the proofs which have been used in affirming the existence of several Glacial epochs, separated by periods whose climatic conditions have been entirely dif- ferent. Contemporary geological literature furnishes us with some examples which demonstrate that there has been an error, and their relations to Prehistoric Man. 461 even in the case of certain classical sections of interglacial de- posits, so that these have now lost the importance that was formerly accorded tothem.” .... “In 1885 I made a visit to Germany, for the purpose of comparing these Post-tertiary deposits with the corresponding deposits of Russia. The results of my journey were then published in Russian, and later were compiled by Mr. Sjogren in German and in Swedish, so that they have become accessi- ble to the savants of western Europe. Among other things, I prove in those reports a complete analogy between the Russian (Quaternary deposits and the German types; with only this dif- ference, that over a vast expanse in central and northern Russia there is a complete absence of traces of interglacial deposits, and of the moraine of the second glaciation ; and that the eastern limit of the second glaciation must pass through Lithuania and the Baltic region. It is true, that in the detailed geological literature of Russia we frequently find announcements of the discovery of interglacial beds at one point or another in middle Russia, or even in southern. Nevertheless, none of these cases can be taken seriously, as I believe. Often they are called forth only by the false idea that all the details of the Quaternary deposits of northern Germany ought to be discovered everywhere in Russia.” . . . Proceeding to describe with more detail the deposits of cer- tain districts, he enumerates the four following as the principal strata in Finland : (a) Old stratified sands and clays, intercalated in a few places between the crystalline rocks and the moraine. (6) Unstratified clays, clayey sands and pebbly moraine, mostly blue (grzses) with polished, sub-angular, striated blocks —the moraine profonde of the first glaciation, according to the Swedish classification. (¢) Stratified sands and clays, with some rounded gravel— the “interglacial” beds. (d) Unstratified, clayey gravel, sand and clay, mostly yellow, with morainic pebbles and bowlders—the moraine profonde of the ‘‘second glaciation.” In discussing the age of these de- posits he says: “As to the advance of the glacial epoch in Finland and the time of the formation of the two morainic clays, the terminal moraines and osars, nothing is yet known with certainty. However, we have as yet no reason to distinguish here, as a fact irrevocably proved, the deposits of the first glaciation, interglacial deposits, and those of the second glaciation, as in Germany and Scandinavia. All the phenomena known up to the present time connected with the glacial deposits of Fin- land can easily be explained by a single, continued glaciation, 462 Nitikin on the Quaternary Deposits of Russia and by a single glacier subject to oscillation. In short, no interglacial deposits are here known containing animal and vegetable remains. The morainic clay of the type (0) alone is distributed over the interior of the country, and only in the border portions of the country does it seem to be separated into two types (0) and (d).” The author gives summary accounts of the deposits in seven different regions, as follows: 1. Finland, and the government of Olonetz. 2. The Baltic region and the Waldai Mountains. 3. Poland and Lithuania. 4, Central Russia. 5. The region of morainic deposits near the limits of their distribution. 6. The region of steppes in southern Russia, beyond the He of elaciation. The southeastern region of Russia. The whole makes a pamphlet of thirty-four large octavo pages. It is, however, only the summary of a more detailed report which he is soon to publish. It closes with the follow- ing : “ Principal Theses.” 1. “The subdivision of the stone age into paleeolithie and neolithic epochs should be preserved for European Russia, because it here coincides with the geological divisions into Pleistocene and modern, which are in their turn based upon eee ae data. 2. “The study of the glacial deposits of Finland and of the western region furnishes no proof of the existence of two dis- tinct glacial epochs and an interglacial epoch. All the facts can be explained by the phenomena of the oscillation of the eee at the time of its gradual, but irregular, retreat. 3. “If however one accepts the Swedish and Prussian theory of the subdivision of the glacial period into two epochs and an interglacial epoch, the second glaciation cannot have extended beyond the western region, in a certain part (com- paratively restricted) of the Baltic region, of Finland and of Hae government of Olonetz. 4. “The other portion of Russia subjected to glaciation, has only one morainic stage, corresponding to the deposits of the first glacial epoch of the Swedes.. 5. “ At the epoch of the more extended glaciation the major part of Russia presented the aspect of a desert of ice, similar to that of Greenland, carrying no moraine upon its surface, and presenting no elevation free from ice, where forest vegeta- tion could be preserved. and their relations to Prehistoric Man. 463 6. “The time corresponding to the interglacial epoch and the second glaciation of the Swedes, was probably, for the greater part of Russia, the epoch of the formation of the ancient lake deposits, the loess, and the upper terraces of the rivers, which constitute the principal repository for the bones of the mammoth and other extinct mammals, which abounded here while Scandinavia and Finland were still covered by the glacier. 7. “In accordance with the composition and genesis of her Quaternary deposits, European Russia may be divided into a series of typical regions which are very characteristic, although resting upon differences which are scarcely recognizable, but which illustrate none the less the life of the immense Russian plain during the Quaternary period, and the formation of her superficial deposits. 8. “In the second portion of the Glacial epoch, or of the pleistocene, the mammoth and other large mammals inhabited southern and eastern Russia in great numbers. As the glacier retreated these animals advanced toward the north and north- west ; toward the close of the pleistocene they reached Finland for a very short time, and then disappeared entirely through- out the whole extent of European Russia, but probably later in its northeastern part and in Siberia. 9. “ Man lived contemporaneously with the mammoth dur- ing the second part of the glacial epoch along the limits of glaciation, possessing an industry well advanced, and making use of fire among other things, but producing implements solely of flaked flint. As the glacier retired, man advanced toward the north and northwest: he arrived in Finland and the Baltic region after the close of glaciation and after the dis- appearance of the mammoth; but man himself possessed already the more advanced culture of the neolithic age, and besides implements of trimmed flint, he knew how to make implements in polished stone, pottery, ete. 10. “ European Russia shows no traces of man in the first part of the Pleistocene, or of any more ancient man.” 464 O. Fisher—Rigidity not to be relied upon Art. LIV.—Rigidity not to be relied upon in estimating the kartl’s Age; by OsMonpD FiIsHER, Cambridge, England. Ir is impossible not to admire the ingenious argument by which Mr. Clarence King* reasons that, assuming the earth to be rigid, the temperature gradient must be such that, within the first few hundred miles at least, it cannot inter- sect the curve which he uses to express the fusibility of igneous rock under the pressure corresponding to the depth. Placing this before his mind, he was led to obtain an examina- tion of the rock diabase at high temperatures to be made by Dr. Barus;+ and we owe a debt of gratitude to both these gentlemen for an interesting addition to our scanty store otf knowledge of this obscure class of subjects. On comparing Dr. Barus’s results with those obtained by Professors Riicker and Roberts-Austen for the dolerite of Rowley Regis, we are struck by the considerably higher value of the melting point of diabase, which is about 1170° C., whereas that of the dolerite was found to be under 920° C. On the other hand, Dr. Barus makes the latent heat of fusion of the diabase to be 24, whereas that of the dolerite is 49 ;¢ thus the latent heat of the rock which has the lower melting point is more than double that which has the higher. When, however, by means of the above considerations Mr. King endeavors to fix a limit within which the age of the earth must lie, it is clear that the rigidity of the earth must be first established. In proof of this he refers to the “ unshaken re- sults of Ld. Kelvin (Sir W. Thomson) and Professor G. H. Darwin,” and to “the further arguments for rigidity advanced by Professor 8. Newcomb§ from the data of the lately ascer- tained periodic variation of terrestrial latitude, as together warranting a firm belief in the rigid earth.” I hope it will not be thought presumptuous if I endeavor to point out what these authorities have really determined. And first of Professor 8. Newcomb’s discussion of the periodic variations of latitude. On referring to the article in the monthly notices of the Royal Astr onomical Society,$ it will be found that he proposes two modes of explaining the phenomena. The first hypothesis which he examines is an elastic yielding of the solid earth, and he comes to the conclusion, that the phenomena recently dis- * This Journal, Jan., 1893. ¢ Ibid, Jan., 1892. + Appendix to the writer’s ‘‘ Physics of the Harth’s Crust,”’ 2d ed., p. 18, 189]. See also the account of the experiments, Phil. Mag., Oct., 1891. § For March, 1892. in estimating the Earth’s Age. 465 covered may be accounted for in that manner, if the earth is slightly more rigid than steel; but he does not stop at this ex- planation. He goes on to say, “ we have next to consider the effect of viscosity of the earth. Those geologists, who have given special attention to the subject, regard it as well estab- lished, that the earth yields under the weight of deposits, as if it were a thin crust floating upon a liquid interior, and must therefore be a viscous solid, if a solid at all.” He then states, that the phenomena observed might in such a case be pro- duced, if some disturbing cause acted, adding, “a vera causa was pointed out some years ago by Sir William Thomson in the motions of the winds and oceans, and especially in changes in the polar ice cap.” Thus it appears that Professor New- comb does not consider that there may not be a possible alter- native to the hypothesis of steel-like rigidity; and evidently he does not regard the question as settled, for the concluding words of his paper are, “but under the actual circumstances we must await the results of further investigation into the whole subject.” Professor Newcomb tells us that, in the case of a viscous earth, “the poles [of rotation and figure] would eventually ap- pear to meet, unless separated from time to time by [disturb- ing] causes changing one or both of them.” ) To account for the “ soft- phosphate” phase; (c) To account for the presence therein of “* plate-rock.” Peninsular Florida first appeared above water in early Mio- cene times, in the form of numerous small islands of Eocene limestone, stretched along what would later be the Gulf coast —corresponding in position to parts of the present counties— Suwanee, Columbia, Lafayette, Levy, Hernando, Citrus, Pasco, Sumter, and the western parts of Marion and Allachna. Twenty miles eastward of this main line facing the Gulf, was this smaller cluster of islets we have under consider ation, ‘then braving the Atlantic. Denudation of these islands by the sea imparted to them at many points the water-worn low bluffs with pinnacles, such as are visible on any part of the present coast composed of rocks like these. Notably may be instanced, St. Mark’s Bay, and Deadman’s Bay, of the Gulf side. Upon shores of this nature were laid down the deposits deseribed in the foregoing pages. The varieties of this class of phosphates in Marion County alone, comprise in mining language ‘‘ hard rock,” “ laminated- rock,” ‘ plate-rock ” and “ soft-phosphate.”’ The explanation offered herewith of the geneszs of these phosphates, is based upon the hypothesis of the original depo- sition of guano. In a rainless region the deposits would have remained in form similar to those of the Chincha islands. In the present case in a region of much rain and great moisture, the guano beds became converted into the phosphates here encountered. The arrangement of land and sea in the Miocene age rendered the deposition of immense deposits of guano quite possible. Only upon such secure island homes, away from the predatory animals of the continent, could the sea-birds have successfully maintained their breeding grounds. The waters of such an archipelago at that age teemed with life, which with the rich vegetation of warm shallow seas afforded ‘ample food. , M. I. Pupin—FLlectrical Oscillations, ete. 503 Having the material deposited, adequate to furnishing a supply of phosphoric acid, the process of change to the present forms followed as a natural consequence, from the attendant circumstances in due course of daw. The guano beds after the leaching out of their carbonates and other soluble materials, became very compact, yet not entirely impervious to water. It is probable that some waste of material by solution is con- _ tinued in degree to the present day. Cavities are found in the most compact beds of the “ hardest rock.” Small cavities in close contiguity became finally sepa- rated by mere plates, and in this condition are called “damz- nated-rock.” By further disintegration such laminated rock is broken up into fragments greater or less, and is then “ plate-rock ”—-such as is found mixed up with more finely comminuted material in the deposits of Anthony and Sparr and Fairview clinging to the walls of the pinnacles of Eocene limestone. Still further progress of the disintegrating process results in the masses of “soft-phosphate”’—-the impurity of the final material depending in part upon the amount of clay originally contained in the immense deposits of the original rock, and partly upon the amount of extraneous matter washed in. That the fragments of “ plate-rock” should cling to the walls of the pits is the natural result of drainage being more ener- getic in the center of the hopper than at the sides; at the same time the middle portions become dissolved or reduced more quickly and more completely than the exterior. Art. LXIL—On Electrical Oscillations of Low Frequency and their Fesonance; by M. I. Pupry, Ph.D., Columbia College. Arm elle [Continued from page 429. ] V. Hlectrical Resonance in mutually inductive circuits. a. The impressed Hlectromotive force is a simple harmonic. —The primary circuit consists of a coil which is in series with a condenser and an alternating current machine which gene- rates the impressed e. m. f. KE sin pt. The secondary circuit consists of a coil joined in series to a condenser. The second- ary coil consists of several parts, some or all of which are under the inductive action of the primary circuit. The 504 M. L. Pupin—FEleetrical Oscillations of electrostatic capacity of the coils is small in comparison to the capacity of the terminal condensers. oucault currents and hysteresis losses are supposed to be negligibly small. The symbolical expressions of the generalized form of Ohm’s law will be, in the well-known notation of Maxwell :— L = 4M a + Re + P, = E sin pt ! dy dx ( Nt apt ae J Remembering that a circuit consisting of coils whose coefi- cient of self-induction is L and a condenser of capacity C in series with these coils may be treated analytically like a closed circuit with no capacity but having a coefficient of self-induc- tion equal t * where p is the pulsation of the im- pressed e. m. a it is ash that the integrals of (9) are obtained ~ from the well-known integrals of the ideal transformer t by the following substitutions :— art aa pMN, =a - t AS aa pee! 1 pMs po rN =k + Ce CEES © PN; +S When the circuits are in resonance to the impressed e. m. f. then both L, and N, are zero. Hence = oN Pf ounaD ic i Caine pie +RS8 sin Pp eee pME 7 = NEL RS (10) ——— COSGU wie The corresponding amplitudes of the condenser potential differences are given by ‘ SE le ae pl pie +RS OOo 40 | ME cated) Pa ap lite ; pM? +RS8 ° J Let W, = work done in the primary circuit. W, = heat developed in primary circuit. * See this Journal, May 1893, p. 425, footnote. + Fleming: Alternate Current Transformer, vol. 1, p. 154. Pupin: Practical Aspects of the Alternating Current Theory, Transactions of the American Institute of Electrical Engineers, Vol. vii, May 1890. Sed Low Frequency und their Resonance. 505 See, ee Hence W, — W, = work transferred from the primary to the secondary circuit. | w,—W, —_1___ = ¢ = ratio of transference. . W : A simple calculation gives ; pM 1 ~ pM?+RS The higher the frequency the higher wili be the ratio of transference other things being equal. The curves expressing —) HE the relation between the resistance in the secondary circuit as abscissee and the amplitudes of primary and secondar y currents and potential differences in primary and secondary condenser 506 M. 1. Pupin—Flectrical Oscillations of as ordinates are given in Fig. 1. The current ctrves are given in Fig. 2. (I am very sorry that these diagrams have come out very indistinct in the reproduction. ) With small resistance in the secondary the efficiency is high but the output is very low, and vice versa, when the resistance in the secondary is large then the primary current is large but the efficiency is low. With ordinary transformers we have just the opposite re- lations, namely, the lower the resistance in the secondary the larger is the current in the primary. Here, however, owing to the fact that the counter electromotive force in the ‘primary produced by the variation of the secondary current differs by half a period in phase from the primary impressed e. m. f., it is evident that the larger the secondary current the smaller is the effective e. m. f. in the primary cireuit and hence the smaller is the current. Let E, = counter electromotive force in the primary due to variation of the secondary current. Then E,=M ae = oAraRS sin pt. Hence effective e. m. f. in the primary = E sin pt — E, RSE : = PEERS sin pt. When S = 0 then the primary current would be equal to zero but the secondary would have its highest value ee = pM These few remarks seem suflicient to clear up the rather sur- prising relations which the curves in fig. 1 illustrate. When the frequency is very high, say 10* periods per second, then as long as S does not increase beyond the value at which RS is comparable to p’M’ so long will = ats sin pt | pM’ yo = z cos pt pM ‘ ole \ (10") Pian SE —— P pe 00 6b o- 6 Ps ae 18 is = pn pM Qo,oto O70 J Denoting the limiting values of these quantities (for S = «) by brackets we shall have Low Frequency and their Resonance. 507 (i a sin pt ! (y) = 0 a Cele) ignai pl (CE) aaa 1p E | Bo = 4 J as it should be. The curves given in fig. 1, fig. 2 hold true in this case also but with this characteristic difference that for all variations of S between 0 and a considerably large limit (especially if R is very small, as in the case of Tesla’s high frequency circuits) the secondary current and secondary potential are practically constant. The higher the frequency the larger is this limit. More than ordinary interest is attached to the relations given in (10), because they give an approximately correct account of the electrical flow in the secondary circuit of an induction coil when the primary is excited by a Tesla high frequency alternator, the primary coil of the induction transformer, a condenser of suitable capacity and the alternator being con- nected in series. It must be observed, however, that since in general the induction coil which Mr. Tesla employs in his experiments does not differ essentially from the ordinary induc- tion coil except that practically no iron is used—it is evident that the secondary coil has distributed capacity which if not necessarily as large as the capacity which would bring this cir- cuit in resonance to the impressed e. m. f. at Mr. Tesla’s high frequencies is certainly far from being negligibly small in com- parison to it. For this reason equations (10°) do not give the exact mathematical relations of Mr. Tesla’s circuits. It is evi- dent, however, that the values which these equations assign to the secondary current and secondary potential are the largest values which Mr. Tesla’s circuits can possibly yield. I do not find a single discrepancy between the theory just given and Mr. Tesla’s experimental results. A fuil discussion of these results from the standpoint of this theory would lead me far beyond the limits of this paper. A few brief observa- tions relative to the agreement between theory and Mr. Tesla’s experiments* seem desirable : a. On account of the considerable internal capacity of Mr. Tesla’s induction coils there is a critical speed of the generator at which a large secondary coil by its own internal capacity will be in resonance to the impressed e. m. f. If it is desira- * See Mr. Nikola Tesla’s lecture in the N. Y. Electrical World, vol. xviii, July 11, 1891, p. 20. Am. Jour. Sc1.—THIRD SERIES, Vout. XLV, No. 270.—JuNneE, 1893. 35 east hye * 508 M. I. Pupin—Electrical Oscillations of — EN ea She arg fr Seapets * E ey { ig eS) mae ee he Am. Jour. Sci., Vol. XLV, 1893. -— - = = ! ae ee roa = _ Plate Il. G : 4000°C. c i 3900° Acoo ae 8 z 3000°C. — | (== CHART oF | DISTRIBUTION OF EARTH-TEMPERATURE i ee : AND MELTING POINTS OF DIABASE FOR THE SUPERFICIAL .08 OF RADIUS E- Initial excess (Temperature) are A-Years of secular cooling p so, Gradients atof correspond with surface rate of 50 fect tol’ F. Gradients toi correspond with surface rate of 75 feet tol F. Am. Jour. Sci., Vol. XLV, 1893. Plate III. A Meteoric Stone which fell at Bath, South Dakota, Aug. 29th, 1892. Weight, 462 pounds. Photographed with metric scale. Am. Jour. Sci., Vol. XLV, 1893. Plate V. Am. Jour. Sci., Vol. XLV, 1893. > NECTENS, Marsh. CLAOSAURUS AN Plate VI. XLV, 1893. Am. Jour. Sci., Vol. Oe \\ N | kd Restoration of ANOHISAURUS COLURUS, Marsh. One-twelfth natural size. Big Discounts on Minerals till July ist. Special Offer.—In order to secure funds with which to meet heavy obligations maturing July 1st, we make a most extraordinary offer. On all purchases for which we are paid ‘‘Spot cash” prior to July ist, we will allow discounts as follows: 20 per cent. on purchases netting less than $10.00 25. per cent. a BO if $10.00 to $50.00 334% per cent. so aul ef $50.00 to — $100.00 40 per cent. ey oe ‘* $100.00 to $1,000.00 45 per cent. sf ie over $1,000.00 Special arrangements will also be made with customers desiring to profit by the above offer, but who have not the ready cash. ‘This offer will positively be with- drawn July ist and will never again be made. It applies to all minerals in our stock - both in New York and Chicago stores, viz. specimens, collections, blowpipe minerals, microscopic mounts and gems, except that we cannot take time to select anything of lower price than 25 cents. Should the rush of orders be so great as to» prevent our filling them all during June, we reserve the right to send the material as soon as possible after, but we must in every instance be paid cash in full prior to July ist. We also reserve the right to withdraw this offer at any time. SOME THINGS FROM WHICH TO CHOOSE. Sulphur Crystals and Groups, 50 cts. to $7.50. : Rubellite in Lepidolite, California, 25 cts. to $50.00. ; Amazon Stone, cleavages, Va., exceedingly fine, 25 cts. to $2.50. ee Ge EHgremont, Bigrige or Stank Mine, Mexico, Bad Lands, Bisbee, 25 cts. to $10.00. 5 Fluorite, green, blue, pink, yellow, white, purple, 25 cts. to $10.00. Barite, England, fine groups and crystals, 25 cts. to $3.50. Hematite and Quartz, England, very beautiful, 25 cts. to $2.00. Sphalerite, England, Mo., or Binnenthal, 50 cts. to $10.00. Apophyllite, Mexico, 25 cts. to $12.50. Amethyst, Mexico, 25 cts. to $3.50. ; Proustite, Pyrargyrite, Stephanite, Polybasite, Argentite, $1.00 to $12.50. Prasopal, the beautiful green opal, 50 cts. to $2.50. Precious Opal, Australian and Mexican, full of fire, 25 cts. to $10.00. Hyalite, Mexico, very choice, 25 cts. to $2.50. Opal Agate, Mexico, beautiful, 25 cts. to $2.50. Cassiterite, W0od-Tin, Mexico, 25 cts. to $1.50. Topaz xls., Mexico, Japan, Urals, 25 cts. to $12.50. Laumontite, Nagyag, extra large, fine crystals, $1.00 to $10.00. Hauerite xls, 25 cts. to $10.00; Gold, Silver, Copper, Lead. Hiddenite xls, 25 cts. to $10.00; Rutile xls, N. C., 25 cts. to 50 cts. Auerlite, $1.00. Epidote xls, Tyrol, very fine, 50 cts. to $5.00. Pink Grossularite xls, loose and in matrix, 25 cts. to $2.50. Descloizite, bright scarlet, 25 cts. to $2.50. Chalcotrichite, Arizona, extra fine, 25 cts. to $5.00. Malachite and Azurite, 25 cts. to $5.00. Stibnite, Japan, 25 cts. to $10.00. z - Labradorite, Sunstone, Jasperized Wood, Agates, Crocidolite. Herkimer Quartz xls, Ark. Quartz, Pyrite twins and groups. Smithsonite, Adamite, Laurionite, Phosgenite. Gem Tourmaline xls; Gem Beryls; Gem Sapphires, Rubies ; Zircons. Eudidymite xls.; Orangite; Cobaltite; Manganite; Bismuth. Argyrodite, Roselite; Ullmannite, Arsenic. Antimony. Rowlandite, Thorogummite, Fergusonite, Cyrtolite, Allanite. Tysonite, Bastnasite, Phenacite, Bertrandite. Anatase, Adularia, Acanthite, Domeykite, Stromeyerite. Brookite, Hudialyte, Monticellite, Aegirite. Aguilarite; Livingstonite ; Orpiment; Realgar. Pollucite; Beryllonite; Matlockite; Altaite; Lehrbachite. Diamond xls, Senarmontite; Sylvanite; Nagyagite; Tiemannite. Essonite, Ouvarovite, Spessatite and Salida Garnets. Prehnite, Hexagonite, Millerite, Mountain Cork, Stalactites. Rhodonite, Troostite, Willemite, Zincite, Franklinite. GEMS. Rubies, 510.00; Sapphires, $2.00 to $5.00; Opals, 50cts. to $10.00; Tourmalines, 50 cts. to $5.00; Chrysoberyls, $1.00 to $25.00; Garnets, 50 cts. to $5.00; Amethysts, 50 cts. $10.00; Aquamarines, $1.00 to $5.00; Topaz, 50 cts. to $20.00; Moonstones, 25 cts. to $5.00; Oligoclase, Diopside, Beryllonite, ete. GEO. L. ENGLISH & CO., Mineralogists, 64 EAST 12TH ST., NEW YORK. World’s Fair Branch Store: — Souvenir Bazaar, 6408 Stony Island Avenne, Chicago. CONTENTS. Arr, LIL.—Electro-Chemical Effects due to Magnetization ; thy by..G:°O: Squink 2 eee i ee ee LIl.—Nikitin on the Quaternary Deposits of Russia and their relations to Prehistoric Man; by A. A. Wricut__ _LIV.—Rigidity not to be relied upon in estimating the Miscellaneous Scientific Intelligence—National Academy of Sciences: Agus EKarth’s Age; by O. Fisumr.---. Cie Soe eee ae cee 464 | LV.—Treatment of Barium Sulphate in Analysis; by J. 1. PHINNEY. 55 5 Oo ee ee 468 LVI.—Validity of the so-called Waliala Beds asa Division of the California Cretaceous; by H. W. Farrpanns..-. 473 LVII.—Nature of Certain Solutions.and on a New Means of investigating them; by M. C. Lma____.._...-.-.- = 478 LVI1II.—Mineralogical Notes; by A. J. Mosns__-----. .--- 488 LVIX.—Pentlandite from Sudbury, Ontario, Canada, with remarks upon three supposed new species from the — same Region: by S: ho PuNRInED. =. 2/225 95 eee LX.—Notes on the Geology of Florida: Two of the lesser but typical Phosphate Fields; by L. C. Jounson-.-.-- LXI.—Electrical Oscillations of Low Frequency and their Resonances; by ME i Popineg sae SS ee ee 508 SCIENTIFIC INTELLIGENCE. Chemistry and Physics—Loss of Energy due to Chemical Union, Gorz, 520,23 Preparation of Acetylene, MAquonNE: New Alcohol of the Fatty Series, Sunp- WIK, 521.—Identity of Caffeine and Theine, DuNsTAN and SHEPHEARD: Lehr- buch der allgemeinen Chemie, W. OstwaALpD, 522—Simplification of Tesla’s — Experiments: Loss of Electric Charges in diffuse light and in darkness, E. BRANLY: Influence of the character of metallic points on alternating discharges of Electricity between them, Wurtz, 523.—Registration of Magnetic variations, ESCHENHAGEN: Discussion of the Precision of Measurements with examples — taken mainly from Physics and Electrical Engineering, 8. W. HoLMAN: Prac- — tical Physics: An Introductory Handbook for the Physical Laboratory, W. F. BARRETT and W. Brown, 524. Geology and Natural History—A new Geological Society, 524.—Zeitschrift fur praktische Geologie, KraumMann: Annals of British Geology 1891, J. F. BLAKE: Materialien zur Mineralogie Russlands, N. YON KoKSCHAROW : Reports of the Missouri Botanical Garden, 525.—H, lH. SEATON, Obituary, 526. —Disco- liths in clay beds, A. M. EDWARDS, 526. Philosophical Society, 527.—Hydrostatics and Elementary Hydrokinetics, G M. Minonin: Elementary Mechanics of Solids and Fluids, A. L. SELBY: Poole Brothers’ Celestial Planisphere and The Celestial Handbook: Practical Asi omy, MIcHTE and HarLow, 528. oh i aes ity Qe yey : PG petty t a tian ar rel tty - | A ibhtbibh dyyets ASQ Aan ae y)PRBUREBELAAAR AAAs! AY os we vs af a a ba ge } A® ae 5 © 5) BU ad NB why Ty) \4 “woes AL lL Pte iT a 287 PP, NiY Raley | Tate | pith a Ad days. ytd pat ae ene | a Te | Anes ARR TANAA A. acu wy y Ty Maly | su ie gis nenSaan Pret hpi eet - Sern. one tha & “hk w am > \o Man oe] Aja i a A) aaane t 4, 3 ‘4 BAS At te E i y ' cant 3 meu ; wm, \- Bee Ts e “ee Vea Wal bad pid LiALL I Re 5 1 seen “4 h ae > Ane. Pa ane 4 Mak iy he » ‘iy aly! he Ga, Sma a 5 | YI \ . S YH pit Met CUE TEPUEMeE Ea ts PAY Y TTP ws aR aU eet Pha ni Peter re | Peeeliee ~ os 4 bn. iE ; BAetaane ] Vy rN TF a i ‘ : ee Ae WR hay Q) , ral Pa a! | om eae aati LaRhens , sana ldeas eile Avan i\pbheaaeee ata b. 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A aN wiih TY Py eT ye CL aE ent fa pm oy bg Bay Nt! aM ams Se Gat) Bhp) Peg amy oe ee A od be ‘ ti 3 Say ea a _ a Vis & ay a ote hee a el Del eYSu Uy r tal TT, 3 9088 01298 5461