hel ew eran elenpielwry wiele renee ; ° WN erate elite wratelelele wer tatete eiere f OES REY ENE ilideth dated. tthe tn os ae hte a tae aaa eee eee . r iets ne BhASAE Dae ee ele ee eee itt ae fg “ eel wind . eerie | eee: iia ebien De eaaaN ae BNR, |) Sinsle AY Pa ens penist eRe Sake eae yr ‘ ang VW: a » ‘3 Ba tT) eS ; 1 ay we 1” ‘os \e Abed Woe - penn wide : 4 TMA A | Nevw @ Aad - My Nn any An VUP Fray * yu Aaa EET 4s ala Let ’ wif remy eel cree A ai ages Vp P My “ / Pee Lah SR {| 11 MBAR NPN AD am Bleidell 1 Hele LONVA NANA - TPT iq dong, Ve ws i me gecpesy Shia, orn y! digi phan 00 ir aay a e Fi ivi a ty WM Jay | iy tM ( Ahh +, by nm cal AAT | Wut aNgts The8 ny TN rene, y nt wt She _ fA ‘ Lb A Z| lob phiisaees f | : M4 ML ce ot ; Nyy i : iA y ve Nh, ih D £ aAvw : ‘yy, At Pr) y «. VG 4 Ar nace ee y \ wy = <1, fg NAA si ay tte aS An. Myr WOON. 1 iteie 4 me ayn / Tt) ‘wertrere, 4 iy ria pep A} a tees “ TELE ta apf 4 Nye fee : * ; 7 we W Vo % Ws gal Bt 14 vy Ne Non Re eed bd » tt r A : } oy " Pa Py y AhiN ass Vy sabes ph aes ‘ vy omy, bn? “ ] r| Mise ee Th sm yosa’ oN it iT ; ne | Mi, | Se aay ‘\ Mid ior wm f J ) S we 9 oe ee Wy H os “A | | | | os aye fn ont Vip Hye b « ( , ‘ t y ~ | waa sat th sf Moers Sy ame GS | a sTeweoe ‘Varnernre as’ 1 Plea NP ata lanl bal Bist Po aly 54 PET TT | arn ws d erent f'n Coe r, daly Wor = i) Bau adc | “ rh See, OM —*\ AS oe eH ree ‘@. ai’ hil ‘ goalie, debit \ dhe ah dy \ soe itt | PY hha | | a AN vevearmnt Sneaceceeaese 4 Na Wy Vy. *Veeee ASet aS bad | Tt Ses M One ie ear MATT VOUS e, ata A > Reale t, i ar : Ld Mad 4 Nolet | hi OG A PC bee - . v8 AA bt ‘e ela la LTO Neonat nel tertile ns 1H wt wy, UN ae HT vill | | pelealeledaalaneO ois Me od Wind AES ; ned - & “eri pays Pit AH HWig Wey, ea, olan May AA peel Es 5 hI g Ay Nt sina ie : Bene} ante CI ae: el LAS \ pte tenes 4 Nh 4° 4 arr stant a we a : f « fC A : AN " wy enna PMIITN etn 4h ee “Ne Nth a. ; yA DR ‘ill AAA TC RUN hes BAU LTS a feeb «A <4S on Rape ye a BN 4 PBA, a “ Bivisyayy: wor? ee i alban’ Nyt el \ j : a OLR A Koy Pramvepe qr aie ii oe NARA PR A ae Vt . couue Cie hanftnrenmanna’? A Reg ee tT ade PULL iad tal al » = Pere eeey re {atari re oH y- teiaydy we Le abide {ha o 8 es WA ard 5 hentai 1A bd) | a gates, \ | nfs Pre RRR iets | ILI i it last ali IO dalle ) | bl ee eabtpdtvibd uddee, ||| |) | 1) 1! oe Sha | hark Virnrerres: TE MA Me OD dg JPE Ste oat | ny | \ Vy Mn Ti vip! Vig’? wo Mind anernnee erp : RADA LS Oaaan A p My ae ee cttnee ft Eten We weve sPeanaes Uy Britta haa wt ren pe BO a OT are nea eh NERS PAK oe TA POSEN ne teres ne Foe eee tte AE ve et rede I ‘ wa SS al ay vA Niece Saene asa wonay. ; IN AAA NT de ae ‘Q Wl iy ops: peas yeah bit 1) etanatd o's vn Pel apie RT beets hhh See pe Heo AN | UA 1 MY aie aL PP | z BP sas Mange PS " a, My ~ ty AAA || ‘ BSF yes ate! ~ 1 DAP A A BL Hh vee. | : ‘s Wouye MBy. Ny "% en EST delel y eee rey -s goers \ : Whe: apes apewtill vyathe ANC o Ve enseganqent | \ Ny gilt eee yi | ~ s AAD bY | ss Dany re be er wel nlal ctrededna dP rgd er Vite A EES ahd d shakin uN Nise OE emit iy TNA co OPT Ra ryinAlU Nyy 8 > ae se THE ey oh ly eA: JOURNAL OF SCLENCE. ' JAMES D. anp EDWARD 8. DANA. ASSOCIATE EDITORS Proressors JOSIAH P. COOKE, GEORGE L. GOODALE and JOHN TROWBRIDGE, or Campringe. Proressors H. A. NEWTON anv A. E. VERRILL, or New Haven, Prorressor GEORGE F. BARKER, or Pamape.puta. THIRD SERIES. VOL. XXXVII.—[ WHOLE NUMBER, CXXXVIILI.] Nos. 223—228. JULY TO DECEMBER, 1889. WITH XII PLATES. NEW HAVEN, CONN.: J. D. & HE. 8. DANA. 1889, CONTENTS. Vv Number 225. Arr, XXIII.—Feasibility of establishing a Light-wave as the Ultimate Standard of Length; by A. A. MicuEtson Page ema VV MEO RIGBY 27018 Seats a ee Bees aye crear SIL XXIV.—Carboniferous Echinodermata of the Mississippi Basins bye Chin wESy a aneurin SS acer 186 XXV.—Energy Potentialized in Permanent Changes of Moiecular Configurations; by C. Barus.--------.---- 193 XX VI.—Contributions to Mineralogy, No. 44; by F. A. INGE ELPUN gegt ty eis ne Rc eas RU MEN BAUR SNS ee Stee Sa 198 XXVIH.—Period of Rotation of the Sun; by H. Crew_.__. 204 XXVIT.—“ Grand Gulf” Formation of the Gulf States; by TE CUIOHING ONG Sues ein LOU AN al Seis Mee yan a Nn a 213 XXIX.—Radiant Energy and Electrical Energy; by J. Hes yy AS ERD) GB ease ye on at Neca IS pen NUL CE OTe AC a 217 XXX.—Note on the fossil Spider, Arthrolycosa antiqua Ol Elangcely: ba CAN Dm CHIR): seit ie) o Ns eae eae 219 XX XI.—Paragenesis of Allanite and Epidote as Rock-form- ing Minerals ; HOV AVE NE PORBS( bets Uh mye ee ei 223 XX XIIL—New locality of the Camptonite of Hawes and RVOSeniouschisy lo yiehynie NASON) ou Uli 0) Sanam een eke 229 XXXIII—Determination of the value of the B. A. Unit of Resistance in Absolute measure, by the method of Lo- renz; by L. Duncan, G. Witxkss and C. T. Hurcuinson 230 XX XIV.—Properties of Allotropic Silver; by M. C. Lea___ 237 XXXV.—Ring Systems and other Curve Systems produced on Allotropic Silver by Iodine; by M. C. Lza.._.__--- 241 XXX VI.—Notes on some Native Iron Sulphates from Chili; os aeed eld MEACICIN DOS mts ete UN NETL Sg ae es tie Baal 242 SCIENTIFIC INTELLIGENCE. Physics.—Hlectrical Waves in Conductors, Hertz, 246.—Disintegration of Sur- faces by means of the Ultra Violet rays, P. L—ENarp and M. WoLr, 247. Geology and Mineralogy.— ruption of Baldai-san, in Northern Japan, on July 15, 1888, Y. Kikucui, 247.—Mastodon or Elephas with fragments of charcoal at Attica, Wyoming Co., N. Y., J. M. CLARKE: Illustrations of the Fossil Fishes of the Devonian Rocks of Canada, J. F. WHITEAVES: Notices of some recently de- scribed minerals, 249.—Lehrbuch der Mineralogie, C. HINTZE, 251.—Mazapilite, KOENIG, 252. Botany and Zoology.—Ueber Entstehung und Wachsthum der Zellhaut, E. ZAcH- ARIAS: Volvox, L. KLEIN, 252.—Zur Kenntniss der fixen Lichtlage der Laub- blatter, G. KrapBe: Flora, oder Allgemeine botanische Zeitung: Utilization by plants of free atmospheric nitrogen: Monographiz: Phanerogarum Prodromi nune continuatio, nune revisio Kditoribus et pro parte auctoribus ALPHONSO et Casimin De CanpouLe. Vol. Sextum. Andropogones, auctore, EH. HACKEL, 253.—Angewandte Pflanzenanatomie, A. TScHIRCH: Report on the Mollusca from dredgings of the Steamer ‘‘ Blake,” H. Dan, 254. Miscellaneous Scientific Intelligence—Soaping Geysers, A. HAGUE, 254.—Proceed- ings of the Colorado Society, Part 1: Chemistry of Photography, R. MELpoua, 255.—Ostwald’s Klassiker der exakten Wissenschaften, 256. Obituary.—Euias Loomis, 256. vi CONTENTS. Number 226. Arr. XXX VII.—Origin of Normal Faults and of the Struct- ure of the Basin region; by J. LEConTE __.-_-------- 257 XXXVIII.—Cireuvlar Polarization of certain Tartrate Solu- tions; ITs by. J. i. Lone 222.2 2220 eS ee eee ee 264 XXXIX.—Gustatory Organs of the American Hare, Lepus Americanus'; ‘by Pf! PuckRrRMAN es: 24222 oe. eee 277 XL.—Output of the Non-condensing Steam Engine, as a Function of Speed and Pressure; by F. EK. NipHer ..-_ 281 XLI.—Ratio of the Electromagnetic to the Electrostatic Unit of Electricity; by H. A. Rowranp, with the assist- ance of EK. H. Haru and L. B. eee OU Res Sie er 289 XLIL.—Determination of v, the ratio of the Electromagnetic to the Electrostatic Unit; by E. B. Rosa --.-_-2.-2.: 298 XLIITI.—Some suggestions upon the method of grouping the formations of the middle Cretaceous and the employ- ment of an additional term in its nomenclature ; by G. EE LDRIDG mai Sees tee ae 313 XLIV.—Some Florida Miocene; by D. W. Lanenpon, JR. _. 322 SCIENTIFIC INTELLIGENCE. Chemistry and Physics—Heat of Combustion of Carbon, BERTHELOT and PETIT, 324.--Molecular Mass of Dissolved Substances, Witt and Brepie, 325.— Boiling point of Ozone and the Solidifying point of Kthylene, OLZEWSKI, 326. —Constitution of the Thionic acids, BERTHELOT, 327. Geology and Mineralogy. — Geological Society of America: North American Geology and Palzontology, 8. A. MILLER, 328.—Note on the composition of Uraninite, W. F, HinLepranD: Minerals from Franklin, N. J., G. A. KorEnte, 329. Miscellaneous Scientific Intelligence.—Parallaxes of the fixed stars, 329.— American Association for the Advancement of Science, 331. Obituary.—-GIUSEPPE MENEGHINI, GEORGE H. Cook, 336. ERRATA. Pages 323, 324, for Sumpter, read Sumter. Page 329, line 20, for NO. read UO». CONTENTS OF VOLUME XXXVIII. Number 223. ; Page Arr. I.—A new Erian (Devonian) Plant allied to Cordaites; Biya Sie NViM DAWSON sees ef NE alae ae ee 1 IL.—The Law of Thermal Radiation; by Wu. Ferren..-.. 3 III.—Stratigraphic Position of the Olenellus Fauna in North America and Hurope: by C.D WaAncomm 252 2222552 es: 29 IV.—Notes on the occurrence of a Leucite Rock in the Absa- roka Range, Wyoming Territory; by A. Hacue -_---_- 43 V.—On Allotropic Forms of Silver; by M. Carry Lea _... 47 IVa.—The Peridotite of Pike County, Arkansas; by J. C. Branner and R. N. Bracxerr, With Plate I .\__... 50 Vie On Wirao: by MY CaaraRp eo oko l Sores 59 VII.—Notes on the Crystallization of Trona (Urao) ; el K. PEP ACYGR: Bi Ge pegs vere er OEY als CAPM DN er NS SY OL Sa eens 65 VIII—On prevailing misconceptions regarding the Evidence which we ought to expect of former Glacial Periods ; Rpivigre as CRO Tete ss SHG cre Ne se Oa Ruste ye a Aa ar SU 66 IX.—Mineralogical Notes, on Fluorite, Opal, Arabes and Dramronde: bye Gyles Kein Zils save at es es es es ee eae (2 X.—AppEnpi1x.—Discovery of Cretaceous Mammalia; by O. C. Maxss. - With Plates Il, 111, lV, and V -....-_ 81 SCIENTIFIC INTELLIGENCE. Chemistry and Physics.—On the action of Hydrogen peroxide on Chromic Acid, BERTHELOT: On the Atomic Mass of Chromium, Rawson, 74.—On the new Element Gnomium, MiLuER: Concentration of Electric Radiation by lenses, Lopge and Howarp: Wave-length of the principal line in the Spectrum of the Aurora, Hue@@ins, 75.—Quartz as an insulator, Boys: Light and Magnetism, 8. BIDWELL: Telephonic vibrations, FROHLICH, 76.—On an Hlectrostatic Field produced by varying Magnetic Induction, Longe and CuaLrooK, 77. Geology and Mineralogy.—¥ossil Fishes and Fossil Plants of the Triassic Rocks of New Jersey and the Connecticut Valley, J. 8S. NeEwperry, 77.—Map of the rigion of Duck and Riding Mountains in Northwestern Manitoba, J. B. Tyr- RELL: Bulletin of the American Museum of Natural History, J. A. ALLEN and R. P. WHITFIELD, 78.—Plattnerite from Idaho, H. A. WHEELER, 79. Miscellaneous Scientific Intelligence.—Luminous night-clouds, 79.--American Asso- ciation for the Advancement of Science: Sir Wm. Dawson on New Erian Plant, 80. SSS iv CONTENTS. Number 224. Page Arr. XI.—Observation of Sudden Phenomena; by 8. P. LANGLEY Lawl U abi s, Seep see Be RES Cee rr ctro-photometric Comparison of Sources of Ar- AAG Illumination ; by Epwarp L, Nicnors and W1z- iam §. RANKIN. ...--205.5--4-22 202-265) eee XIU1.—Possibility of Hemihedrism in the Monoclinic Crystal System, with especial reference to the Hemihedrism of Pyroxene ; by Grorce BH. WiriiamMs ~222 eee 115 XTV.—Earlier Cretaceous Rocks of the Northwestern portion of the Dominion of Canada; by Grorce M. Dawson 120 XV.—A new occurrence of Gyrolite; by F. W. Crarke__ 128 XVI.—Action of Light on Allotropic Silver ; by M. Carry Dia) See ee a ee at eg 129 XVII.—Certain Porphyrite Bosses in Northwestern New Jersey: ;. by J. Wi-KmMp ooo... 33 ee 130 XVIII.—Great lava flows and intrusive trap sheets of the Newark system in New Jersey; by Nerson H. Darron 134 XIX.—Recent Explorations in the Wappinger Valley Lime- stones and other formations of Dutchess Co., N. Y.; by W. BO Dwicurs =(With (Plate: Vill); 22282322 eee 139 XX.—Silicic Acids; by GrorcE F. Becker _.---.--....- 154 XXJ.—AprEenprix.—Notice of Gigantic Horned Dinosauria fromthe Cretaceous; by \O. C. (MARSH {2.22 see 173 XXII.—Discovery of Cretaceous Mammalia. Part II; by ©. C. Marsx. (With Plates VII and VIII.)_ 22: = ei SCIENTIFIC INTELLIGENCE. Chemistry and Physics—Vapor Density of hydrogen fluoride, THORPE and HAMBLY, 157.—Decomposition of Potassium chlorate by heat, McLrop, 158.— Synthesis of Formic aldehyde, JAHN, 159.—Identity of Seminose and Mannose, E. FiscHER and HiRSCHBERGER: Synthesis of Uric acid, BEHREND and ROOSEN: Crystallized Tungsten, R. N. RippLE, 160.—Influence of Solar radiation on Elec- trical phenomena, S. ARRHENIUS, 161.—Disruptive discharges in gases, M. Wo.F: Selective reflection of Metals, H. RUBENS,- 163. Geology and Mineralogy.—Tertiary Volcanoes of the Western Isles of Scot- land, J. W. Jupp, 163.—Genus Tubicaulis of Cotta, G. SrenzEL: Faune du Calcaire d’Erbray (Loire Inférieure), C. BaRRois: Notes on Epidote and Hanks- ite, C. BopEwiG, 164.—Plattnerite from Idaho, J. D. HAWKINS and E. W. Haw- KINS, 165.—The Minerals of New South Wales, etc, A. Liversinge: Eighth Annual Report of the State Mineralogist of California, W. IRELAN, 166. Botany and Zoology.—Beitrage zur Kenntniss der Oxidationsvorginge in lebenden Zellen, PFEFFER: Biologia Central-Americana, HEMSLEY, 166.—A Hand-Book of Cryptogamic Botany, A. W. BENNETT, 168.—Bathymetric conditions as to growing corals and other species of Tizard and Macclesfield Banks, in the China Sea, W. U. Moore and P. W. Bassert-SmitH: The Coral Reefs of the Hawaiian Islands, A. AGassiz: Fisheries and Fishing Industries of the United States, G. B. Goopr, 169.—Darwinism, A. R. WALLACE, 170. Astronomy.—Researches on the Spectrum, Visible and Photographic, of the Great Nebula in Orion, Hugerns, 170. Miscellaneous Scientific Intelligence.—Hlizabeth Thompson Science Fund: The Assayer’s Manual, B. Keri and F. L. GARRISON, 172. Obituary.— JOHN PERCY: MARIA MITCHELL. CONTENTS. vil Number 227. Page Arr. XLV.—Mathematical Theories of the Earth; by R. 8. ’ WOODWARD na tease tee eho eter sashes ee elo) 88 f XLVIL—Darkened Silver Chloride not an Oxychloride; by JE (Ovi oigd Di oy ase ys aera ee eters se EN es, NO nie oe cays 9 356 XLVII.—Observations on some of the Trap Ridges of the East Haven-Branford Region, with a map (Plate IX) ; loved (O)s, De Woy yaa) cise Sat eteen a paral 9s Pry me reer aay he 361 XLVIII.—Theory of the Mica Group; by F. W. CrarKeE __ 384 XLIX.—Probable Law of Densities of the Planetary Bodies ; sya el OO KeM ems coe eae at VM SNe tart ea ee OE EAE 393 L.—Improved Standard Clark Cell with Low Temperauure Coefficient ; by H. S. Carwart.--- - LU SESE ele ee Mh Se AID De Plefdomarphe of Native Copper after Azurite, from Grant County, New Mexico; by W. S. Yuatxs_-__-.-- 405 LII.—Note on the Relation of Volume, Pressure and Tem- perature in case of Liquids; by C. Barus__-_-..----.- 407 SCIENTIFIC INTELLIGENCE. Chemistry and Physics—Colloidal Cellulose, Guignet, 408.—Watts’ Dictionary of Chemistry, H. F. Mortey and M. M. P. Muir, 409.—Treatise on the Prin- ciples of Chemistry, M. M. P. Murr: Definitions adopted by the International Congress of Electricians, Mascart, 410.—Lightning and the Hiffel Tower: Transmission of power by Electricity, DEpRez: Dissipation of negative electric charges by sunlight and daylight, J. KistER and H. Grirent: Photography of the invisible portions of the Solar Spectrum, Cu. V. ZENGER: Carbon Spectrum, H. KAYSER and C. RUNGE, 411. Geology.—Movement of the Upper ice of Glaciers over the Lower: Ice-Age in North America, and its bearings on the Antiquity of Man, G F. Wrient, 412. —Anouual Report of the Geological Survey of Arkansas for 1888, J. C. BRANNER, 413.—Jurassic Plants from Kaga, Hida, and Echizen, (Japan), MatTasrRo YoKOYAMA: Rivers and Valleys of Pennsylvania, W. M. Davis, 414. Botany and Zoology.—Die natiirlichen Pflanzenfamilien, A. ENGLER and K. PRANTL: Guide pratique pour les travaux de Micrographie, BEAUREGARD et GALLIPPE: Contributions to the Physiology of Growth, J. WORTMANN, 415,.— Atlas deutscher Meeresalgen, F. Scutrr, P. Kuckuck, J. REINKE, 416.—Mono- graph of the Horney Sponges, R. VON LENDENFELD, 417—The Bermuda Islands; a Contribution to the Physical History and Zoology of the Somers Archipelago with an examination of the structure of Coral Reefs, A. HEILPRIN, 418. Miscellaneous Scientific Intelligence.—British Association: Scientific Papers of Asa Gray, C. 8. Sargent, 419.—Popular Treatise on the Winds, W. FERREL: Sixth Annual Report of the Bureau of Ethnology to the Secretary of the Smithsonian Institution, J. W. PowELt: Elementary Algebra, R. GRAHAM: Numbers Universalized, an Advanced Algebra, D. M. LENSENTG, 420. ERRATA, Page 371, line 8 from top, after razlroad add cut; p. 372, line 9 from bottom, for welded read joined ; p. 374, line 19 from bottom, after 450 add feet; p. 375, line 11 from top, for # 2 read £& 1. = ” = SST 7 eee ae eb sie a Te ve ee ; To Ter vill CONTENTS. Number 228. . Page Arr. LIIL.—Temperature of the Moon; by S. P. Lanerey, with the assistance of F.. W. Very _--...-_.J-- 226 S3aaan LIV.—Lower Cretaceous of the Southwest and its relation to the underlying and overlying formations; by C. A. WHITE 25 8l Se shol el See ee ee 440 LV.—Hinge of Pelecypods and its Development, with an attempt toward a better subdivision of the group; by WH. Dann {2.06.5 =~ Se ee ee ee 445 LVI.—Magnetism of Nickel and Tungsten Alloys; by J. TROWBRIDGE. and 8S; SHELDON..-- ._-_ .--5 25 22a LVIL—Note on the Measurement of the Internal Resistance of Batteries; by B. O. Perrcr and R. W. Wittson --- 465 LVIII.—Relation of the Uppermost Cretaceous Beds of the Eastern and Southern United States; by R. T. Hiri: and the Tertiary Cretaceous Parting of Arkansas and Texas; by R. T. Hitz and R. A. F. Prnross, Jr. .---- 468 LIX.—Description of several Yttria and Thoria Minerals from Llano County, Texas; by W. E. Hippen and J. B. MACKINTOSH 2 J232 Dis Sree DAW eeie ia ee 474 LX.—Appenpix.—Skull of the Gigantic Ceratopside; by » OFC. Marsay With) Plate Xi 2 Soe 501 SCIENTIFIC INTELLIGENCE. Chemistry and Physics.—Spectroscopic Discrimination of the Rarer Earths, CrooKkEs, 486.—Commercial Organic Analysis, A. H. ALLEN, 490.—Text Book of Organic Chemistry, A. BERNTHSEN: The spectrum of Hydrogen: Spectrum of gases at low temperature: New photographic lens: Pin-hole Photography: Blue color of the sky, 491.—Passage of Electricity through gases: Purification of Sewage by Electricity: Elementary Lessons in Heat, 8. E. TILLMAN, 492. Geology and Mineralogy.—Tertiary Flora of Australia, Dr. CONSTANTIN: Royal Society of Canada: Contributions to Canadian Paleontology, Canada, J. F. WuHiITEAVES: Chemical and Physical Studies in the Metamorphism of Rocks, A. IRVING, 493.—Hudialyte (?), W. E. HippEn and J. B. MacxkinrosH: Cata- logue of Minerals and Synonyms alphabetically arranged for the use of Museums, T. EGLeston: Materialen zur Mineralogie Russlands, KOKSCHAROW: Index der Krystallformen der Mineralen, V. GoLDScHMIDT: Hinleitung in die Chemische Krystallographie, A. Fock, 494.—Composition of uraninite, 495. Botany.—What is a Phyllodium ?, 495. Miscellaneous Scientific Intelligence——National Academy: New Bulletins of the U. 8. National Museum, published by the Smithsonian Institution in 1889, 498. Obituary. —GrorGe H. Coox, 498.—Lxro LEsQuEREUX, 499.—JAMES PRESCOTT JOULE, 500. INDEX TO VOLUME XXXVIJII, 501. ERRATUM. The notes at the bottom of p. 476 should be transposed. Chas. D. Walcott, U. S. Geological Surv: y- VOL. XXX VIII. JULY, 1889. | Established by BENJAMIN SILLIMAN in 1818. THE AMERICAN JOURNAL OF SCIENCE. EDITORS JAMES D. anp EDWARD §S. DANA. ASSOCIATE EDITORS Proressors JOSIAH P. COOKE, GEORGE L. GOODALE and JOHN TROWBRIDGE, or Camepringe. . Prorressors H. A. NEWTON anv A. E. VERRILL, oF New Haven, Proressorn GEORGE F. BARKER, or Puinaperputa. THIRD SERIES. VOL. XXXVIIL—[WHOLE NUMBER, CXXXVIIT] No. 223—JULY, 1889. WITH PLATES I-V. NEW HAVEN, CONN.: J. D. & H, 8. DANA. 1889. LUTTLE, MOREHOUSE & TAYLOR, PRINTERS, 371 STATE STREET. | | ET TELE TE TIE TIE EPEAT EEE ET EY EET Published monthly. Six dollars per year (postage prepaid). $6.40 to foreign sub- seribers of countries in the Postal Union. Remittances should be made either by money orders, registered letters, or bank checks, ; en ithe The Most Varied and Complete Stock in the United q United States. Catalogue Free. Recent additions to our stock, resulting from Mr. English’s Five Months tour through the far west, include : VANADINITE. About 5,000 superbly crystallized specimens of brilliant red, orange, yellow and silvery-gray colors. Beautiful gangue specimens and large detached crystals. Prices unpr recedentedly low. A carefully selected suite of six typical gangue specimens, averaging 2x3 inches, and one large loose crystal for $5.00, express charges to be paid by the purchaser. Parties who have not yet become customers of ours will find this an excellent way to give us a trial order. Red Wulfenite, in groups of Octahedral Crystals, 25c. to $3.50. Tabular crystal groups, 10c. to $10.00. Chalcanthite, in fibrous specimens of a rich blue color, 5e. to $2.00. Malachite and Azurite, in beautiful crystals, 10c. to $5.00. Descloizite, in stalactitic druses of crystals of various brilliant shades of red and yellow, 5c¢. to $50.00. Gadolinite, from Texas, 25c. to $2.50. Clinoclasite, Pharmacosiderite, Erinite, Olivenite, and other rare minerals from Utah in far better specimens than heretofore. Borax Crystals from Nevada. Ulexite, in most beautiful fibrous specimens. Other recent additions include Blue Barite Crystals from Colo- rado, Pyroxene Crystals from Canada, Modified Quartz and Rutile from N, C., Beryllonite, Sperrylite, Arquerite, Thorite Crystals, and many other equally rare and desirable species. Minerals by the Pound for Blowpipe Analysis, a Specialty. We aim to secure the purest material obtainable, and guarantee satisfaction. College orders especially solicited. GEO. L. ENGLISH & CO., Dealers in Minerals, — 1512 Chestnut Street, - - Philadelphia, Pa. THE AMERICAN JOURNAL OF SCIENCE [THIRD SERIES.] Art. L—A new Erian (Devonian) Plant allied to Cordaites ; by Sir Wm. Dawson. I HAVE recently, through the kindness of R. D. Lacoe, Esq., of Pittston, Pa., had an opportunity to study a remarkably fine specimen collected by him in the lower Catskill (Upper Devo- nian) at Meshoppen, Wyoming Co., Pennsylvania, and which promises to throw much light on some difficult questions of fossil botany, as well as to add a new and very interesting form to the Devonian flora. The present note is intended as merely a preliminary notice. The full discussion of this unique plant will require a reference to much of the work that has been done in Cordaites, Neggerathia, etc., from the time of Stern- berg to the recent reports of Lesquereux and Fontaine, and I hope will illustrate a number of fragmentary and enigmatical specimens which have long been in my own collections, and which need further study in connection with it. The specimen is a branch or small stem 23° in diameter and 46™ in total length. It is flattened and pyritised, and shows, under the microscope, merely the indications of a pith surrounded by a fibrous envelope, the minute structure of which is not very well preserved, but it is hoped by proper treatment may give some further information. The stem shows portions of about 15 leaves which have been at least 16™ long and 3 to 4™ broad. They are decurrent, apparently by a broad base, on the stem. Their distal extremities are seen in a few cases, but in all seem injured by mechanical abrasion or decay. It seems most probable that they were truncate and uneven at Ay. Jour. Sc1.—THIRD SERIES, VOL. XXXVIII, No. 223.—Juny, 1889. l 2 W. Dawson—New Erian (Devonian) Plant. their extremities. The stem is terminated by a cluster or com- pound corymb of spikes of which 20 are seen. They are slender, but seem to have been stiff and woody, and the largest are about 15™ in length. They have short pointed bracts, and some of them bear oval fr uits, but only a few of these remain, the greater part of them having apparently fallen off before the plant was fossilized. So far the characters do not differ from those of the genus Cordaites, except that in those plants the spikes of fructification are more usually lateral than terminal. A remarkable peculiarity, however, appears in the leaves, which instead of having the veins parallel, have them forking at a very acute angle, and slightly netted, by the spreading branches of the veins uniting with the others near them. This allies the leaves with those of the provisional genus Veggerathia, some of W. Ferrel—Law of Thermal Radiation. 3 which have this peculiarity, as also certain modern Cyeads of the genus Zamia, which Professor Penhallow has kindly pointed out to me. The present plant would seem to be a form of Cordaitew, tending to Neggerathia, which many paleobotan- ists believe to have been a gymnospermous genus allied to Cordaites. The affinities, however, so far as can be judged, are nearer to the latter; and following the example of Grand Eury in his nomenclature of the genera, I would propose the name Dictyo-cordaites for the present genus, and the specitic name Lacoz, in honor of its discoverer. It is apparent that this specimen combines the fructification of the Cordaitee with leaves akin to those of WVeggerathia, thus connecting two groups of paleozoic plants, both of which are now considered as allied to. Cycadew and Tawxinew, and I entertain the hope that when it is fully studied and brought into comparison with other specimens in my collections, or which have been figured and described by other paleobotanists, it will throw additional light on a great number of Paleozoic Canadian leaves, fruits and stems, now designated as Cordaztes, Neaggerathia, Psygmophyllum, Gingkophyllum, Sternbergia, Lepidoxylon, Saportea, ete.; and which have been waiting for some specimen thus complete to bring them into harmony with each other. I hope to be able to bring the whole of this material, which will necessitate some change in the nomenclature of some of my own species, under the notice of geologists at the approach- ing meeting of the American Association. I may add that the oldest true Cordaites known to me is C. Robbiui of the Middle Devonian, which is said to have also been found in the Silurian. C. angustifolia of the Lower Devonian is a somewhat uncertain species. Plants of the genus Vegge- rathia are known in the Upper Devonian. Art. Il.—The Law of Thermal Radiation, by WILuiaM FERREL. 1. Ir is well known that as the temperature of a body is increased, the intensity of its thermal radiation is likewise in- creased, but with regard to the law of increase, or relation be- tween the intensity of the radiation and the temperature of the body, there is still considerable uncertainty even within the temperature range of experiment and observation. The two principal formule expressing this relation are that of Dulong and Petit, given more than seventy years ago,* and that of Ste- * Journal de l’Ecole Polytechnique, xi, 234-294. ¢ W. Ferrel—Law of Thermal Radiation. fan of somewhat recent date.* The object of the present research is to compare these formule with the principal data on hand derived from experiment and observation, and to ascer- tain how nearly they represent the true law, and what modifi- eations of these formule, if any, are still required in order to this. The want of space will forbid my giving any detailed accounts of the experimental data used, and so for these the reader will have to consult the references. Stefan has done some important work in this line of research, and some of his data will be used here and some of his results will be briefly given. 2. Let H = the rate with which heat is radiated by a body from each unit of surface, Tt = the temperature of the radiating body, m = the value of H at the temperature of rt = 0. If we now put (1) H=mnaz this, in the special case in which a=1:0077 becomes the expres- sion of Dulong and Petit’s law. But if the body is not in empty space, but is contained within a perfect enclosure of temperature z,, then by Prevost’s law of interchanges the body receives upon each unit of sur- face an amount of heat H,=ma"°, and hence we have for the rate with which each unit of surface of the body loses heat, (2) H—H,=ma' —ma=ma"(a°—1), in which (3) d6=7—r,. If we now let R = the rate of cooling of the body, C = its thermal capacity, supposed to be the same for all temperatures, ¢ = its specific thermal capacity, o = its specific gravity, s = the area of radiating surface, we then have (4) R=A(a°—1), in which (5) ee le In the special case of a spherical body of radius 7 this be- comes 3m 5') A=— a" reo For inclosures of different temperatures it is seen that these expressions of A vary, with a change of temperature of the inclosure, as @°. Where the inclosure is not perfect, as where * Sitzungsb. Akad. Wien, II, lxxix, 391, 1879. W. Ferrel—Law of Thermal Radiation. 5 the body radiates on the one side through the atmosphere into space, the imperfect inclosure is equivalent to a perfect one of the temperature at which the body would stand in the shade, 3. Again, using the same notation as above except the abso- lute temperatures T and T, instead of z and c,, if we put 7 ae) ete (°) ec this, in the special case of e=4, becomes the expression of Stefan’s law. From this we get m 273° (7) Be ores) = Yo mang 1); in which the quotient BO aoaie ane Tanne anc Io 973° From this form we get (8) R=A(g°—1, in which (9) A= Fa. Hence, for different temperatures of the inclosures, A varies as g,°, or as the e power of T,. In the special case of a spheri- cal body we have ‘ 3m (9 ) Ax Tah * 4. The law of Dulong and Petit is based upon the results of their noted experiments upon the rate of cooling of a large glass bulb filled with mercury within an inclosure of the tem- perature of melting ice and several other temperatures, and the expression (4) in the special case of ¢=1:0077 perhaps rep- resents the observed rates at different temperatures within the limit of the probable, at least the possible, errors of observa- tion. At the time of these experiments, however, it was not understood that the thermal conduction of gases is independent of pressure except at very low tensions, and it was supposed that the conduction at the tensions of 2 or 3™", at which the experiments were made, was very small. Dulong and Petit’s formula for expressing the rate of cooling V in calories per minute due to both convection and conduction, was based upon experiments made at pressures of 720, 360, 180 and 45™™. From these the following formula was deduced : (10) V=0:00919 p°* 61%, in which p is the pressure of the air in meters Their observed rates of cooling at the low air tension of their experiments were corrected by deducting the rates given by this formula, in order to obtain those due to radiation alone. But Stefan has shown that this formula, based upon observations at high 6 W. Ferrel—Law of Thermal Radiation. ~ pressures, gives the effect of convection only, which entirely vanishes before the low tension of 2 or 3™™ is reached. He therefore restores this correction, which is very small, and then the corrected rates of cooling R, in degrees per minute, are those given in the second column of the following table, cor- responding to the values of d in the first, which in this are the temperatures of the cooling body since that of the inclosure was T,=0. é R |2°02(1:00779—1) 0:925(g4—1)|_ R_ |1-592(1-00829—1) 0-730(9*2—1) ane te ee noes 80°) 1°74° +03 +08 | 148° 00 +06 100 | 2°30 —03 00 | 1:96 —05 —02 120 | 3-02 —03 —"03 | 2°60 —06 —02 140 | 3:88 —02 —04 | 3°38 | —'04 —06 160 4°89 +°01 SHE Wee | 00 —-05 180 | 6-10 +08 4°01 | 5-43 +-08 +02 200 7:40 +04 — Ol | 664 +05 ‘00 220 | 8°81 —10 —10 | 7:95 —08 —09 240 10°69 —04 +°08 | 9:74 | —0l +711 These rates are satisfied by the expressions at the head of columns 8 and 4, the former being that of Dulong and Petit’s, and the latter that of Stefan’s law, with the residuals, observa- tion minus computation, given beneath in each column. 5. Stefan has given a formula for computing the rate with which a spherical body within a spherical inclosure is cooled by heat conduction, which is equivalent to 3r (11) "2 =k 6(14+4 is v r(r,—r,)eo'® (1+3a(z+7,)), in which, besides the notation already adopted, v = the rate of cooling in degrees per minute, 7, = the radius of the cooling body, : r, = that of the spherical inclosure, k= the conductivity of air at temperature T=0, a = the temperature coefficient. He puts ,=0:00324, which corresponds to his coefficient 0:000054 where the second is the unit of time. He also puts a=('0027, c=0°0332 and g=13°6. Hence we have co=0°4515. The values of 7, and 7, in Dulong and Petit’s apparatus were respectively 3™ and 15%. If with these constants and data the values of v in (11) are computed for the several values of din the first column of the preceding table and deducted from the second column, we get the values of R in the fifth column, which arise entirely from radiation. But these rates now are not accurately represented by either Dulong and Petit’s or ~ Stefan’s law, with any given numerical coefficient, but they W. Ferrel—Law of Thermal Radiation. 7 are represented by the expressions at the heads of the last two columns of the preceding table with the residuals beneath. These expressions are deduced from (4) and (8) by putting a=1-0082 in the former, and e=4-2 in the latter, and hence they are modifications of Dulong and Petit’s and Stefan’s laws respectively. The residuals are as satisfactory as in the other case. 6. The value of A in (4) or (8), if it were a true expression, is the rate with which a body would cool in empty space at the temperature c, or T,, according to the respective laws, and yet it is seen how different are the values in the preceding case, as seen from the numerical coeflicients in the two eases, the one, 1592, being more than twice as large as the other, 0-730, and yet the two expressions with these very different numerical values of A satisfy the rates of cooling equally well through a range from 80° to 240° C. But the rate of cooling at any given temperature, it is seen, depends upon the differ- ence between the two values of a function of the temperature, and not upon the absolute values of these functions, and it so happens that these differences in the two forms of function, with very different values of A, however, satisfy observation equally well through a considerable range of temperature, although the absolute values of the functions are so different. Little reliance, therefore, can be placed in values of A which best satisfy the observed rates of cooling, as being the actual rate with which the body would cool in empty space. And this is especially the case where the observed rates are through a short range of temperature and not far above the tempera- ture of the inclosure ; for then the values of A and of @ in the one case, and of A and of e in the other, are somewhat comple- mentary, so that in increasing the one and decreasing the other, - and vice versa, the differences, or values of R, may remain very nearly the same through a considerable range of tem- perature. Not only are very different values of A obtained from the two different forms of expression (4) and (8) but likewise from the same general form of expression by giving different values to @ in the one ease, or to ¢ in the other; for these values, especially where the range of temperature is small, may differ considerably, and yet the expressions with proper, though very different, values of A satisfy the observed rates of cooling equally well. For instance, in the preceding case of the rates of cooling observed by Dulong and Petit, although the range is 160°, if the value of a@ is taken a little greater or less than 1-0082 in the one ease, or ¢ a little greater or less than 4:2 in the other, the residuals are very nearly as satisfactory. There is, therefore, a great uncertainty in the value of A which satisfies 8 W. Ferrel—Law of Thermal Radiation. the observations through a considerable range of temperature, and for short ranges it becomes almost entirely indeterminate. The value of mm, therefore, as determined from (5) or (9) with values of A thus determined, cannot be relied upon as being any more than a very rough approximation to the heat radia- pense empty space from a unit of surface at the temperature of 0° C. 7. With the value of A=1:592, as given in the preceding table, and the values of 7, ¢ and o in $5, we get from (5’) with the temperature t,=0, m=0-°7188 of a calorie as the rate per minute with which heat is radiated from each square centi- meter of the surface of glass at the temperature of 0°. Now with this value of m we get from (2), putting 7,=0 (12) H,,,—H, =0:7188(1:0082"" —1) =0:9092 for the difference between the values of H in (1) at 100° and at O°. Again, in the other form of expression of the law of radia- tion, with the value of A=0°730 from the last column of the preceding table, and the values of 7, c, ¢ above, we get from (9’) for the temperature T,=273, in which case g,=1, m= 03296. And with this value of m we get from (7), putting qQ=l, 373 b 4°2 —H —0°35 bal —] )—0:892 (13) H,,,—-H,=0 s200((] 1)=0 8926. The value of H,,,—H, for glass has been obtained experi- mentally by Lehnebach by the method of ice calorimetry with apparently great accuracy.* His value is 0:0152 where the second is the unit of time, or in our notation, the same as that used by Dulong and Petit and Stefan, it is 0°912. This value does not differ much from either of the values above, which are also for glass. In obtaining the values above it is seen that the value of 7=3™ enters into the computation in the expres- sions of (5’) and (9’), and it is doubtful whether Dulong and Petit’s glass bulb was exactly a sphere with a radius of 8%, and so there is some uncertainty with regard to these values. Lehnebach obtained the same value of H,,,—H, for both a bare and blackened glass bulb, and so it would seem that the radiativity of glass at 100° is equal to that of lampblack. This does not accord with some other experiments, and so this is a matter which perhaps needs still further research. If the radiativities are the same, then this value of H,,,—H, applies to both a lampblack and bare glass surface, at least at high temperatures. Stefan reduced these values obtained from bare glass to a lampblack surface by dividing by 0°88 the assumed relative radiativity of glass with reference to lampblack. ] * Poge. Ann., cxlvi, 497, 1875. W. Ferrel—Law of Thermal Radiation. 9 The great differences in the values of m above as obtained trom the two different forms of expression of the law of radia- tion arises from the uncertainty in the values of A upon which they depend. This uncertainty has been explained in$6. The value of m thus obtained would be the true value if the assumed law were strictly correct and the value of A satisfying the observations could be accurately obtained. But for reasons already given different forms of expression, and different values of the constants in the same expressions, giving rise to very different absolute values of the functions, and of the value of m, can be obtained which all satisfy observation almost equally well. The value of m, therefore, thus obtained, can at best be regarded merely as a rough approximation to the true value. 8. By (4) we have for each value of 0 and corresponding ob- served value of R, (14) Iss R a1 and from (8) (15) Js 1 q—l These quotients or values of A, for each value of 6 and Rk, except so far as they are affected by errors of observation, should be a constant if the assumed law is correct. We can therefore test the assumed laws in this way as well as by means of the residuals as is done in $4. Thus Stefan gives the following observed differences in the rates of cooling between a naked and silvered cylindrical thermometer corres- ponding to the values of ¢ grven in the first line below, the temperature of the inclosure being 20°. r) 100° 120° 140° 160° 180° 200° Differences 2°19° 2°96 3°73 4°66 514 Pu (E91 ISH CHL 1:950 1947 1-944 NES) ; | 1-329 1363 1-348 1:34] 1345 1:375 Srevcnisl Sai-7ai 1766 = -1°742 1729 1-718 1-722 | -900 ‘O17 ‘897 891 ‘887 ‘907 The quotients of the first and second lines are those given by Stefan for the laws of Dulong and Petit and his own respec- tively, the first being obtained from (14) by putting @ = 10077, and the second from (15), or its equivalent, by putting e=4. The near equality of these quotients was considered as a confirmation of the approximate correctness of both laws, as deduced from these data, within the range of temperature used. But the quotients of the last two lines are obtained from the same expressions by putting ~=1:0082 in the former and ¢ =4-2 in the latter, and these last quotients satisfy the condition ot equality about as well as the former. This method of test- 10 W. Ferrel—Law of Thermal Radiation. ing the laws is, therefore, even more uncertain than that by means of the residuals as in § 4, and it leaves considerable un- certainty with regard to the best form of éxpression of the law or the values of the constants to be used in the expression. 9. From the differences in the rates of cooling of a bare and a silvered cylindrical thermometer from t=75° to t=137° Stefan obtained from his law the following quotients : 4648 4588 4621 4624 4641 These indicate that Stefan’s law must hold pretty well for this range of temperature, the mean temperature being 106° ; but the range of temperature being short, the law might be varied considerably, that is the value of ¢ in (15) might be con- siderably greater or less than 4, without affecting much the equality of the quotients. Dividing the differences in the rates of cooling by (1:0077° —1) he obtained the following ratios : 6212 6236 6327 6373 6432 These numbers do not satisfy so well the condition of equal- ity, but show, allowing for small errors of observation, a regu- lar increase of values with increase of temperature, indicating that Dulong and Petit’s law in some measure fails, and is not as correct as Stefan’s law for this range of temperature, and that a value of @ in (14) considerably greater than 1:0077 is re- quired here. Again, Stefan obtained the quotients below corresponding to the values of 6 in the first line, the temperature of the inclosure being 14:7.° n) 48'18° 55°58 80-98 Quotients 5407 5418 5417 by Stefan’s law. : " ) 7044 7105 7277 by Dulong and Petit’s law. These indicate, so far as can be inferred from so short a range of temperature, that Stefan’s law, at these temperatures, is more nearly correct than that of Dulong and Petit, the latter quotients again indicating that Dulong and Petit’s law fails here and that a value of @ in (14) greater than 1:0077 is re- quired to make the quotients equal. It should be considered here that where the law of the radia- tion of glass is deduced from the differences in the rate of cooling of bare and silvered bulbs, it is assumed that the laws of both are the same. This is, most probably, not the case, but the radiation of the silver is so small that it cannot affect the results much. 10. We come now to the examination of a series of experi- mental observations of a different kind, in which the relative radiativities of the face of a Leslie’s cube coated with lamp- W. Ferrel—Law of Thermal Radiation. 11 black and filled with mercury at different temperatures through arange of 240°, was determined from the deflections of the galvanometer needle of a thermopile. The third column of the following table contains the deviations y of the needle, as obtained by Rosetti,* corresponding to the absolute tempera- ture T in the first column and the differences 0 between these and that of the inclosure, 23°8°, in the second column. T 5 y |O—C |} 40-4(2-007%° 1) | 22°3(g4—1) | 19-6(g#?—1 329°6 32:8 10:0 | +071 —1°5 —1°6 —0°8 369°6 72°8 29°5 | +0°8 —0°8 —1°8 —O'1 389°6 92°8 42°8 | +1°'5 +0°9 —1°2 +11 409-6 |119°8 || 55-0 | —1-2 0-7 3-6 1-2 429°6 132°8 72°5 | —1:2 +1°0 —3'l —0°5 449-6 | 152-8 || 91-5 | 2-3 +14 a35 —0'9 469°6 172°8 || 116-7 0-0 +4°9° —0:°7 +1°8 489°6 192°8 || 141°9 | —0:7 +4°8 —0°8 +1°2 509°6 212°8 || 169°5 | —2:1 +3°1 —2°0 —0°5 529°6 232-8 || 204°0 | —O-1 +3°2 0-0 +0°5 549°6 252°8 || 239°5 | —0°4 —1°3 —07 —1°6 569°6 172°8 || 283°5 | +4:3 —3:°9 +3:°3 +01 The usual care necessary in such experiments seems to have been taken. He says that the experiments were all made at least twice, and whenever, between the first and second experi- ment, a difference of one, or at most two divisions were found, and of five-tenths of a division in the lower temperatures, a third and fourth experiment were made to obtain a correct average. Rosetti devised an empirical formula to express the relations between the deviations of the needle, y, and the temperatures, which, expressed in our temperature notation, is (16) y=aT’d—bo in which a4=0°00000335131 b=0:0636833 This expression represents the observed values of y in the table above with the residuals, O—C, in the fourth column. But this expression, it is seen, ignores Prevost’s principle of exchanges, since it is not composed of two similar functions for different temperatures, the one representing the heat radia- tion of the heated body and the other that of the inclosure or surroundings, as in the expressions of (2) and (7) of which Dulong and Petit’s and Stefan’s laws are special cases. 11. Applying Dulong and Petit’s law to these observations, the values of y are represented by the expression at the head * Memorie della Classe di Scienze Fisiche, Mathematichi, e Naturale della R. Academia dei Lincei. Serie 3°, vol. ii, 1877-1878. 12 W. Ferrel—Law of Thermal Radiation. of the fifth column in the preceding table with the residuals, O-—C, in the same column beneath. These are not satisfactory, and no modified expression of Dulong and Petit’s law obtained by giving a different value to @ in the general expression of (4) gives residuals which are more satisfactory. It is evident, therefore, that neither Dulong and Petit’s law, nor any law of the general form of (4), represents satisfactorily the law of radiation, at least according to these experiments, through a temperature range of 240°, though this is done through a range of 160°, as we have seen, § 4, in the case of Dulong and Petit’s experiments. Applying Stefan’s law, the values of y are represented with the expression at the head of the sixth column with the resid- uals beneath, which are also unsatisfactory. But if we use a modification of Stefan’s law, making the exponent e in (8) equal to 4:2 instead of 4, we get with the expression at the head of the last column the residuals beneath. These are very satisfactory, being small in comparison with the observed values of yin the third column and having a pretty regular alternation of plus and minus signs throughout the whole range. This comparatively simple formula, therefore, repre- sents the results of Rosetti’s experiments much better than his own, (16), given above, as is seen by comparing the residuals in the last column with those of the fourth column. From these comparisons it seems that. some function of the general form of (6), of which Stefan’s law is a special case, represents the law of radiation, and (8) deduced from it, the law of cooling, much better than those of (1) and (4), since the results of experiment are well represented by a special case of the former through a range of temperature of at least 200°, for the one isolated experiment at a distance of 40° below the lowest of the others should not have much weight, since the value of y is very small. . 12. Although neither Dulong and Petit’s law, nor any ex- pression deduced from the general form of (4) by giving dif- ferent values to A and a, represents well Rosetti’s experiments through the whole range of temperature, yet by dividing these into two parts we find that the part from T=329°6 to T=489°6 is represented by the expression y=37-0 (1:0082°—1) with the residuals (O—C) below corresponding to the values of 0 in the first line : 6) 32°38 ~ 72°85 99-8) | 119;8) 3278) 62 Sun eoluemmozas O=0 —r4 —06 408 1-0 01 —05 =e 0-0 These residuals are satisfactory through a range of 120°, from 0=72°8 to 0=192°8 the middle of which corresponds to a tem- perature of about 157°, and they indicate that with a value of W. Ferrel—_Law of Thermal. Radiation. 13 a—1:0082 instead of 10077 as required by Dulong and Petit’s law, the experiments are well represented through this range. This comports exactly with what has been found in the case of Dulong and Petit’s experiments, in which the value a=1-0082 was required for the temperature range of 160° from 80° to 240° the mean of which corresponds to the temperature of 160°, which is nearly the same as the 157° above. The first residual, corresponding to 0=32°8, being negative, indicates that for lower temperatures the value of @ must be still greater. 13. If we now take the range of observed values of y from 0=192°8° to d=272°8°, the mean temperature of this range being about 257°, we find that they are represented by the expression y=51-87 (1:00692°—1) with the residuals, O—C: f) 192°8° 212°8 232°8 252°8 272°8 O—C 0°0 —1:0 +1:0 —0°9 +0°3 These residuals are satisfactory for the short range of 80°, and indicate that for this range of higher temperatures the value of a required is approximately 1:0069, though as has been explained this value, determined from so short a range, is somewhat uncertain. It is evident, however, that a value of @ much less than that of Dulong and Petit’s law, is required for these higher temperatures, and especially smaller than 1:0082 re- quired for the first division of the experiments comprising the lower temperatures. We have now seen that the general expression of (4) appar- ently holds in the special case of a=1-0082 through a tempera- ture range of about 160° with a mean temperature of 160°, and that there are no values of A and @ in the general expres- sion of (4) that will satisfy experiment and observation through any long range of temperature, but that for temperatures con- siderably above 160° the values of @ required are less than 1-0082, while for lower temperatures values which are greater are required. The value of @=1:0077 most probably holds through a considerable range with a mean of about 200°. 14. It is well known that for high temperatures Dulong and Petit’s law gives an increase in the intensity of radiation with increase of temperature very much too great, and that here a value of «@ less than 1:0077 is required, and one which decreases with increase of temperature. And that the value of a must be much greater than 1:0077, and even than 1:0082 at ordinary temperatures was shown by Provostaye and Desains by means of the thermopile.* For temperatures below 160° they found that the deviations of the galvanometer needle could be repre- sented by the general expression of (4) by putting a=1-009. * Daguin. Traité de Physique, vol. ii, p. 90. 14 W. Ferrel—Law of Thermal Radiation. The value, also, obtained by Winkelmann for temperatures between 0° and 100° is a=1-:0089.* Heat radiation should vanish down at the temperature of absolute zero, and hence Dulong and Petit’s law cannot hold down at very low temperatures, since it does not make the radiation vanish there, though it reduces it to about one-eighth of what it is at 0° C. For the same reason no special case of the general expression (1) can hold at any low temperature. A value of a gradually increasing and approximating to infinity as the zero point is reached would be required. This being the case it is reasonable to suppose that the increase in the value of @ may commence at very high temperatures and con- tinue on down, though this is a consideration of no great weight. iia what has been shown, therefore, it is evident that Dulong and Petit’s law holds through only a comparatively short range of temperature, and the same is true of any func- tion of the same general form, but by giving different values to a in the expression of (4), smaller at high temperatures and much greater for low temperatures, an expr ession may be had which represents the difference of radiation between the body and the inclosure, and so the rate of cooling, approximately through a considerable range of temperature. 15. We have seen, $9, that the observed rates of cooling seem to confirm Stefan’s law for a range of temperature from about 50° to 137°, while for higher temperatures, according to Rosetti’s experiments, an exponent of 4:2 instead of 4 is required in the general expression of (8). And according to Schleiermacher’s experimentst still higher values of the ex- ponent ¢ are required for very high temperatures to represent approximately the experiments through any given not very great range of temperature. These experiments, however, indicate that different values of the exponent are required for the different kinds of radiating wire, as is to be expected, since the radiations of different qualities with regard to wave-length are not in the same proportion in the different wires, or the same as that of a glass or lampblack surface. For the bright platinum wires of apparatus I and II, Stefan’s law is satistied at temperatures from 150° to 300°, while in apparatus III with a dark, though rot coated with lampblack, wire, his law is not satisfied until a temperature of about 400° is reached. This probably arises from the want of a perfect vacuum in the tube through which the heated wire passed, for it is well known that it is almost impossible to have such a vacuum as to render the conduction insensible, and the effect of any conduction, which increases nearly in proportion to the temperature, while * Poge. Ann., clix, 177, 1876. + Wied. Ann., xxvi, 287. W. Ferrel —Law of Thermal Radiation. 15 that of radiation increases in a much higher ratio, is to appar- ently diminish the latter, and render a smaller value of the exponent ¢ necessary. But in all cases these experiments indi- eate that there must be a gradual, though small, increase of the exponent, with increase of temperature, and that at very high temperatures this exponent must be greater than that of Stefan’s law. It is therefore reasonable to suppose that at ordinary temperatures, and especially at very low tempera- tures, the value of ¢ is less than that of Stefan’s law, which, we have seen, seems to hold for temperatures from about 50° to BIC It appears, therefore, that neither Stefan’s law nor any other of the general form of (6) with a different value of e repre- sents the true law of nature through the whole range of ex- periments, but that different values of e in (8) are required for different ranges of temperature, and values which increase with increase of temperature, to represent the observed rates of cooling approximately through a given, not very great, range of temperature. But the general expression of the radiation (6), and that of the rate of cooling (8) derived from it, seem to be much better than those of (1) and (4), since only small changes in the value of e with change of temperature are required, and the formule, with any given value of ¢, hold through a much greater range of temperature, as is seen in the case of Rosetti’s experiments, which are well represented through a range of 240° with the value e=4-2, (§ 10). 16. For determining the law of radiation it is necessary to have either experiments on the rate of continuous cooling of a body through a long range of temperature, or to have the observed rates through shorter ranges but for different temper- atures of the inclosure. Very interesting and important ex- periments of the latter kind have been made by Graetz on the rates of cooling of a glass bulb with mercury both in a perfect vacuum, as supposed, and in an inclosure containing air of low tension.* The three temperatures of the enclosures were those of melting ice, boiling water, and boiling aniline, 182-7°.. The ranges of the observed rates of cooling were from 33° to 42°, and these rates were observed down to about 20° above the in- closures. The results were discussed with reference to both Dulong and Petit’s law and Stefan’s. He determined the value of m in an expression similar to that of the special case of (4) in which a=1:0077, for each group of the observed rates of cooling. It is seen how this may be done by means of (4) and (5’) from the observed rates or values of R. He obtained the following three values of m, expressed here in calories per minute instead of per second. * Wied. Ann., xi, 973, and xiv, 232, 1881. 16 W. Ferrel—Law of Thermal Radiation. m=0'7518 for temperature of inclosure 0° m= 0°8286 P - 100 m=0°8118 a 182°7 If Dulong and Petit’s law were correct throughout the whole range of the experiments these values, of course, would be equal, since 7 in (4) is a constant where the law holds. But these values of 7 must be referred, not to the temperatures of the enclosures, but to the mean or middle temperatures of the range of each group, since they are determined from the ob- served rates of cooling within these ranges and are such values as best satisfy the observations. The middle temperatures of the groups are respectively 42°, 142° and 216°. With these values of m for the several temperatures, we get from (1) with II OOKG Hip 1038) yt) Ee — 24645 EIA ol If we now wish to determine the value of @ in the general expression of (1) which will satisfy any two of these consecu- tive values of H, and so give a law which will hold approxi- mately through the whole intervening range and accurately for the middle point, or nearly, of this range, we must have values which satisfy the following conditions: log H,,,— log H,,=100 log a log H,,,— log H,,,=74 log a From these conditions we determine the values a=1:0087 at a temperature of 92° a=1:0073 at a temperature of 179 From these results it is seen again that the value of @ de- creases with increase of temperature, very much in accordance with what has been shown from other experiments and by different methods, except that the last value of @ above is rather too small. We have seen, § 4, that a value of a=1:0082 satisfies very well Dulong and Petit’s experiments for a con- siderable range on each side of the mean temperature of 160°, and that the same value, § 12, satisfies it fairly well through a range of at least 120°, of which the mean temperature, 157°, is nearly the same; but that Rosetti’s experiments through a range of 80° of which the mean temperature is 257°, requires a value of a=1-:00692. 17. Graetz also discussed his results by Stefan’s law, and with the following form of the expression of this law, H=oT", he obtained, where the second is the unit of time: G=1'086 . 10-” for the group with inclosure of 0° C= bye Omen 2 f “s 100 G=15085 - 0m? =f oe 182°7 W. Ferrel—Law of Thermal Radiation. 17 But, in accordance with what has been stated in the pre- ceding case with regard to the values of m, these belong prop- erly to the middle temperatures of the groups, and we get from the preceding expression of H for the several tempera- tures of the middle of each group, making the minute the unit of time: H,,=0°6415 H,,=1:8810 H,,,=3-7224 In order now to determine the value of ¢ in the general ex- pression of (6) which will satisfy any two successive values of H, and so be true fora point very nearly the mean of the two, we have to satisfy the following conditions: log H,,, log H,, =e(log T,,, log T,,) log By —log H,,, =e(log At elo: se) From these conditions with the preceding values of H for the several temperatures we get é€=3'90 at the temperature of 92° e= 4°] 6 66 4 1 "9 These results accord very well with those previously ob- tained by other methods and from other experiments, and in- dicate that the value of ¢ increases with increase of temperature and that Stefan’s law, in which e=4, holds through a considerable range of temperature of which the mean is about 125°. We have seen in § 9 that this same value of ¢ satisfies other experi- ments from 75° to 187°, the mean of which is 106°, while for the higher temperature of about 160° the value of e=4-2 is re- quired. While it cannot be claimed that these results are very accurate, and so a very nice agreement in the comparisons can not be expected, yet taken altogether they indicate very clearly that the value of ¢ must be considerably less for low than for high temperatures. 18. So far, in the general expressions (6) and (8) we have regarded the exponent é as constant, and have found that a constant value of ¢ may be found which will make (8) repre- sent observation through a considerable range of temperature, though the value required is a little greater for high than for low temperatures. It is evident, therefore, that the value of this exponent must gradually increase with increase of tem- perature. We will therefore assume that within the range of experiment (17) e=e,+¢r in which ¢,is the value of ¢ where z=0. With a varying value of ¢ we must change the last form of the expression of (7) to He A ate 18 _ = ——— —= | ingwhich) N77 =— ( ) ce ) 273° Am. Jour. Sci1.—Tuirp Srries, Vor. XXXVIII, No. 223.—Juny, 1889, 2 18 W. Ferrel—Law of Thermal Radiation. since the value of eis now different in the numerators and denominators in the expression. For the same reason (8) be- comes as ; : ms) he 9 — —_-_ — 9 — 0 (19) R A (mr i) in which (20) A Gi anae or in the case of a spherical cooling body (20') es ae TCO 273° With the expression of ¢ in (17) substituted in (19) such val- ues of the constants A, ¢, and ¢ should be found, if the assump- tion of (17) is correct, as will make (19) represent, at least within the limits of possible errors of observation, the observed values of R. In the expression of ¢ above, however, the two terms are somewhat complementary, so that by increasing e@, and decreasing ¢ correspondingly, and vice versa, through a con- siderable range the expression of (18) represents the observed values of R nearly as well through a considerable range of temperature. But with different assumed values of e, and corresponding changes of ¢ different values of A are required, and so there is the same uncertainty here with regard to the value of this constant, and consequently by (20) or (20’), in the value of m, which we have found elsewhere. The value of é, which is found in general to satisfy observations best is about 3:0, though if it be changed to 2-9 or 3:1 or even made to vary considerably more, if the value of ¢ is changed accord- ingly, the residuals are nearly as satisfactory. 19. Slightly different values of ¢ in (17) seem to be required for different radiating surfaces, which is to be expected from theoretical considerations, and seem to be indicated by Schleir- macher’s experiments as pointed out in $15. If we put (21) e=3'0 + 0:000387 we get from (18) with A=0°905 and T,=278°, the values of R in the second column of the following table corresponding to the values of T in the first column: TSR Or C a R O-—C T | R.| O-C —— | — — ee ee 353| 1-48 | 4-05 |//329°6 |) 11-4 | —1:4 || 398%) 2-217 cop 373 | 1:98 | —02 |) 369:6 | 30:5 | —1-0 || 413>\03:91 aeer 05 393 | 2:64 | —-04 || 389°6 | 426 | +0°2 || 433 | 3-74 | —-01 413 | 3-41 | —-03 || 4096 | 568 | —1-8 || 453 | 4-69 | —-03 433 | 4:3 00 || 4296 | 73:4 | —0-9 || 473 | 5-99 | —--06 453 | 5:37 | +:06 || 4496 | 92:5 | —1-0 |) 493 | 7:04! +:-07 473 | 6:60 | +:04 || 469°6 | 114-7 | +2:0 493 | 8:02 | —-07 || 489-6 | 1400 | +1:9 513 | 9°67 | +:07 || 509-6 | 169-1 +0°4 | 529°6 | 2026 | +14 | 549°6 | 240°5 | —1°-0 | 569-6 | 284:0 | —0°5 W. Ferrel—Law of Thermal Radiation. 19 These values of R compared with the corrected observed values of R in the fifth column of the table in §4 leaves the residuals, O—C, in the third column of the preceding table. Hence the expression of (19) with the assumed constants, represents the experiments of Dulong and Petit, with the pre- ceding residuals, which are very satisfactory. With the values of A, ¢ and T, above, and the known values of 7, c and o given in § 5, (20’) gives m=0-4086, which is con- siderably larger than the value 0°3296 in §7. With this value and the value of e given by (21) we get from (18) (22) H,.—H,=0°'8958 This differs but little from the value of (13), § 7, obtained from (7) with the constant value of e=4°2. If instead of (21) we put (23) €=3'°0 + 0°00082 7 we get from (19) with the value of A=25-0 and T,=23°8’, the values of R in the fifth column of the preceding table corre- sponding to the values of T in the fourth column. ‘These compared with the values of y in the table of § 10, give the residuals, O—C, in the sixth column. These are quite satisfac- tory considering the large temperature range of 240°. fii @9) welput A—1:122,\1T,=20°, and (24) e= 3-0 +0-00034 7 we get the values of R in the last column but one of the pre- ceding table, which compared with the differences of the rates of cooling between a bare and silvered thermometer given in § 8, give the residuals in the last column. The preceding values of H, §17, obtained from Graetz’s experiments should be represented by (6) with proper values of m and e, or with the values of H and e for’ given temperatures it should give m a constant for each of these temperatures. With the preced- ing values of H for the temperatures of 42°, 142°, and 216° and with the value of ; (25) ' €=3'0+0°0004 7 we get respectively the following three values of m=0'3792, m=0°3804, m=0°3795 The numerical coefticient of s was assumed so as to make the first and last very nearly the same, but the very near agree- ment of the other with these depends upon the accuracy of (6) with the assumed value. of ¢ above. The difference between the numerical coefficients of ¢ in the expressions of (21) and (23) indicate that the exponent e for glass increases a little more with increase of temperature than 20 W. Ferrel—Law of Thermal Radiation. in the case of a lampblack surface, which was used in Rosetti’s experiments. The value of the numerical coefficient in (24) is a little less than that in (21) though both are for bare glass, but here the law may be slightly affected by the law for the radiation from the silvered thermometer being a little different from that of glass, although the amount of this radiation is very small. The numerical coefficient in (25), although also for glass, is a little greater than in (21), but this small differ- ence may arise from small errors of observation, or perhaps from a lack of a perfect vacuum which has, as explained in $15, the effect of making the law of radiation apparently increase more rapidly with increase of temperature than it otherwise would. 20. If in (18) we put H,,.—H,=0°912, as found by Lehne- bach, $7, we get with the expression of ¢ in (23), which seems to be that required for a lampblack surface, A=04388 and which in this ease is also the value of m since T),=273°.. With this value and the value of e in (23) we get the values of H—H, in the second column of the following table correspond- ing to the different values of 0 in the first column, which are the same as T since t)=0 here. i) H—H, H—H, H—H) H—H, 100 0°9120 0°9120 0°9120 0:9120 90 “7820 "7828 “7810 “T7806 80 "6624 6634 "6609 “6593 70 | 0520 5532 | 0507 5476 60 4503 4513 | 4497 4452 50 "3572 | BIT =... "3575 3518 40 2724 CPA) = ‘2731 *2669 3 1949 71940 | 1955 “1896 20 “123 2321 | "1245 1196 10 "0586 "0585 0597 “0566 But very nearly the same results may be obtained from (7) with a constant value of ¢ for all temperatures, and with a smaller value of m. Putting (26) H—H.=0:3951 (q**°—1) the value of g being unity in this case, we get the values of H—H), in the third column of the preceding table, which differ but little from those of the second column, so that instead of using the expression of (18) with a varying value of @, that of (7) can be used throughout this range without sensible error. The constant 0°3951 is so determined as to make H4—H)= 0-912 as determined by Lehnebach. The value of e=3-833, so determined as to give the best agreement in the two expres- sions, comports very well with the value 3°9 at the tempera- ture of 92° as given in § 17. oO W. Ferrel—Law of Thermal Radiation. 21 We get from (18) by differentiation and substituting for ¢ and @T(=dr) their values from (17), (27) | fen m08 ) ‘i aD 273. Nn M in which M is the modulus of common logarithms. The last two terms within the parenthesis depend upon the variation of é and the whole parenthesis is equivalent to an increased value of ¢. By taking the differential of (18) regarding ¢ as a con- stant we get ASS ine at" o7a° These two expressions become equal by putting T log T (28) ee, FCT +O— ay But by satisfying this condition we simply make the two fune- tions of T increase at the same rate at some given temperature T at the middle point or elsewhere of some given temperature range. If the condition is satisfied for the middle point of the range the two functions may agree approximately through the whole range, but the satisfying of this condition does not generally give the best agreement. For the middle of the range in the preceding table in which T=323°, we get from (28) in the case of a lampblack surface in which we have found c=0:00032, €=3'0+0°00032 X50 +0°597=3'6138 But we have found by a tentative process that the value €=3°833 gives the best agreement of the two functions through- out the whole range of 100°. The preceding value of ¢ would simply make the rate of increase of the two functions the same at the temperature of 50°. But by comparing the difference of successive values in the second and third columns of the preceding table it is seen that the increased value of e makes them a little greater in the latter column in the middle of the range. This furnishes an explanation of the increased value of e required when regarded as a constant. Up at the temper- ature of 160°, or T=433°, which is the middle temperature of the range in Dulong and Petit’s experiments and also very nearly that in Rosetti’s experiments, putting c=0-00088 in this case, we get from (28) e=4:06. The value of e=4°2 was found to satisfy best the observations through the whole range. With e=0-00032 (28) would give a still smaller value in the ease of Rosetti’s experiments, but the value 4-2 was found in this case also to be the best ; but as has been remarked before, a considerable change in the value of e does not greatly affect the residuals in comparing with observation. 22 W. Ferrell—Law of Thermal Radiation. 21. Although the general expression of (2) has not been found to represent observation well through as great a range of temperature as that of (7), yet if we put (29) H—H,=0°652(1:0088°—1), the value of a being 0 in the case of the examples of the pre- ceding table, we get the values of H—H, in the last column of this table. It is seen that the values differ but little from those of the other columns throughout the whole range. It is seen, therefore, how nearly three very different functions, with differing values of the constants, give the same results, and con- sequently would represent observations equally well. In each of these the value of the constant m enters as a numerical co- efficient, and these are respectively, taking the expressions in the preceding order, 0°438, 0°3951, and 0°652. And differences of the same order have been found where these expressions have been applied to results of experiment and observation. We have, therefore, only a vague idea of the real value of this constant. It probably falls within the range of the numbers above, and is undoubtedly much smaller than the value given by Pouillet, 1-146, for a lampblack surface, as deduced from Dulong and Petit’s experiments in accordance with their law, and putting the relative radiativity of glass at 0°80. These values have all been determined from the experiments of Dulong and Petit with a bare glass surface at temperatures from 80° to 240°. But at the temperature of 100° Lehnebach found the radiativity of bare glass and that covered with lamp- black the same. At lower temperatures at least there must be a considerable difference, but not as much as Pouillet supposed. The three forms of expression from which the results of the preceding table have been computed, are equally as well appli- cable to any observed rates of cooling, the law in both cases being the same, but the constant coefficient different, as may be seen by comparing the expressions of H—H, with those of R in (4) and (8). So either of these can be used for all ordi- nary temperatures by using the values of the constants e and @ used in (26) and (29), but the numerical coefficients will of course be different, depending upon the thermal capacity of the cooling body, as is seen from (5) and (9). By Stefan’s law, (7) with e=4, we get, by determining the value of m so as to give H,,,—H,=0°912, (30) H—H,=0°3673(g*—1). This gives the values of H—H, in the last column of the pre- ceding table. The differences between these numbers and those of the other columns are considerable, but if 7 were so. determined as to give the best general agreement, instead of W. Ferrel—Law of Thermal Radiation. 23 making H,,,—H,=0-912, the agreement would be much better. Stefan’s law, therefore, can be used without material error down at ordinary temperatures, for a range even of 100°, by using a value of 7 a little greater than that above. 22. If in (2) we put E equal to the value of H—H, where 6=1, that is, for the rate with which each unit of surface loses heat by radiation in excess of what it receives when the differ- ence between the temperature of the body and that of the inclosure is L° C., we get (31) E=ma"™ (a—1). This value of E is called by English physicists the emissivity of the body at the temperature of the inclosure t,, though this term is often used in the sense of radiativity, or absolute radi- ating power, without regard to heat received from an inclosure. It is seen that, if (2) expresses the true law the emissivity increases as a'°, whatever the value of @ may be. With the value of m and a in (29) we get, where the temperature of the inclosure t=50°, E=0°652 X 10088” x 0°:0088=0'00889. At the temperature of 7,=0, we get K=0:00574. In like manner we get from (7) by putting T—T,=1 and developing 7 (32) B= 570% G Hence, if the form of (7) expresses the true law, the emissivity is as the e—1 power of g,=T,/278, or as the e—1 power of the absolute temperature, which, by Stefan’s law, is the third power. With the values of m and e used in (26) this gives for the temperature T,=50", 0°3951 B2B\7 838 i Re Sas (=) =0'893. At the temperature t,=0, we get E=0-00555. With the values of m and ¢ in (30) we get for 7,=50°, 0°3673 323 EK= O75 1x (=) =0°892. 73 273 At the temperature of 7,=0, this gives E=0-00538. Again, for the more general expression of (18), in which e varies with T, the value of E may be deduced from (27) with- out any sensible error, by using in the first member small finite variations 6H and dT instead of dH anddT. If dT=1°C., then 6H becomes E, and we get erl (33) E=m T log =} M al +eT+e 24 W. Ferrel—Law of Thermal Radiation. This with the values of m in § 20 used in computing the first column of values of H—H, in the table and the values of ¢ and é in (23), we get for t=50° or T=328°, 3237016 323 log 323 ss EK=0°438. pee’ 0°43438 (9:04 -00027-+ 00082 ) =0-00800. At the temperature r=0, we get E=0-00560. There is a very nice agreement in these results from these several different forms of expression at the temperature of 50°, but it is not quite so satisfactory at 0°, which was to be expected, since this is one of the limits of the range to which the several forms are applicable. The values of E above at 0° do not differ much from those of Winkelmann* and Kundt and Warburg,t which, reduced to our unit of time, are respectively 0-00528 and 0-00558. In $7 we have found from Dulong and Petit’s experiments by their law m=0-7188. With this value and Dulong and Petit’s value of a=1:0077 we get from (31), applied as in a preceding example, E=0-00589 at the temperature of 0°, but K=0:02202 at the temperature of 160°. Also with the value of m=0°3296, as obtained from Dulong and Petit’s experi- ments by Stefan’s law, with the exponent e=4°2, we get from (82), E=0-00507 at the temperature of 0°, but E=0-02218 at the temperature of 160°. These values of E from these two different formule agree very closely at the temperature of 160°, but not at the temperature of 0°. This is because these for- mul are derived from expressions which represent experiment and observation through a temperature range of which the mean is 160°, but it is not claimed that these expressions hold down to the temperature of 0°; in fact it has been shown that they do not. The values of E, therefore, from (81) and (82) which have been deduced from these expressions, can be cor- rect only within the limits of the range for which they hold, and not down at 0°. From (83), with the value of e in (21) and the value of m=0°4086, which are the values deduced from Dulong and Petit’s experiments, we get, in the manner of the preceding example, E=0-00574 at the temperature of 0°, but HE=0-02211 at the temperature of 160°. As these values are deduced from a formula which is supposed to be applicable to all tempera- tures within the range of experiment they should be more ac- curate, at least at the temperature of 0°, than the preceding results. The preceding value of E at 160° is very nearly the same as the other two values from expressions less general, but adapted to this range of temperature, and is a mean of the two. The preceding value of E at 0° falls between the two * Poge. Ann., clvii, 497. + Pogg. Ann., elvi, 208. W. Ferrel—Law of Thermal Radiation. 25 former values from formule which are not supposed to hold accurately down to so low a temperature. It is seen from the computed values of E from the several expressions of E, as well as from the expressions themselves, that these values increase very rapidly with increase of temper- ature. Also, that while the values of m, as we have seen, as determined from observation for the several laws and expres- sions, are very scattering and uncertain, the values of E, as determined from the several very different expressions, differ but little. ; 23. The several preceding laws of radiation here investi- gated pertain to the radiations of a lampblack or a bare glass surface, between which there seems to be but little, but of course some, difference in the rate with which radiation in- creases with increase of temperature. According to Violle* this rate is much greater for the short than the long wave- lengths, and the same is to be inferred from Langley’s results, in which it is seen that the maximum intensity with reference to the wave-lengths is thrown toward the end of the shorter wave-lengths in the spectrum as the temperature of the radiat- ing body is increased. The law of radiation, therefore, for the resultant radiation of all wave-lengths must differ very much in different bodies in which the radiativities differ considera- bly from that of a surface of maximum radiativity, according as the predominating wave-lengths in its radiations are toward the one or the other end of the spectrum. The radiativity of bare glass at ordinary temperatures is supposed to be one-tenth or more less than that of a lampblack surface, but if the de- ficiency in its radiation at these temperatures is mostly toward the end of the longer wave-lengths, then it is readily seen that for higher temperatures its relative radiativity, that is, radia- tivity relative to lampblack, must increase and gradually ap- proximate that of the latter, but it could never quite become the same, as it is according to Lehnebach’s experiment at the temperature of 100°. For this reason, also, the absolute radia- tivity in glass must increase with increase of temperature a little faster than that of lampblack, as seems to be indicated by the larger numerical coefficient of c in the expression of ¢ in (21) than in (23). 24. The condition from which the temperature of the sun is determined where the law of radiation is known is (34) 1sle=S= = AN in which S:w is the ratio between the whole surface of a sphere and the part which subtends the same solid angle as * Comptes Rend., vol. xcii, p. 1204, 1881. + This Journal, vol. xxxi, January, 1886. 26 W. Ferrel—Law of Thermal Radiation. the sun at its mean distance, and A is the solar constant. For the several laws of radiation H must be expressed in a function of the temperature as in (1), (6), ete., and we then have the relation between the temperature and the solar constant. Put- ting according to Violle* S : o=183960, the preceding equa- tion becomes by (1), in the case of Dulong and Petit’s law, in which @=1:0077. (35) m(1°0077)T = 45990 A But here as we have seen, §21, there is great uncertainty with regard to the true value of m, and there is also consider- able with regard to that of A, to say nothing of the applica- tion of a law based upon experiments through a range of only 160° being extended up to the temperature of the sun. This, with Pouillet’s large value of m=1:146 and small value of A=1°75 gives a value of 7=1454°. But putting a=1-0082, which has been shown to satisfy the results of Dulong and Petit’s experiments as corrected by Stefan, and using the value of m=0-7188, as obtained in §7, and also a greater value of A, say 2:2, we get t=1456, very nearly the same, though with the same solar constant it would have been considerably less. The true solar constant is probably still considerably greater than this. By means of (6) we get from (34) 4s e (36) m (3) = 45990 A 273 This, with e=4, as required by Stefan’s law, and m=0-4, as determined by him for lampblack and A=2-2, we get T=6122° or t=5849° as the sun’s temperature if it had the radiativity of lampblack. The temperature of the sun ob- tained upon this hypothesis is often called the “ effective tem- perature of the sun,” but this must be very much less than the real temperature, since the radiativity of the sun is undoubtedly rauch less than that of lampblack. Pouillet supposed it might not be more than one-tenth as much. With the value of e=4:2 which is required to satisfy the results of Dulong and Petit’s experiments as corrected by Stefan, and using the values of m=0°3296 corresponding, §7, which, according to Lehnebach should be the same for a lamp- black surface, we get from (86) with A=2:2, T=5528 or t=525D5°. If in (86) we regard e as a function of t of the form of (23), and use the value of m=0°488 as determined in §20, the value of T=2837° or t=2064° is required to satisfy this equation with A=2°2. This latter is therefore the effective tempera- * Annales de Chimie et de Physique, vol. x, 1877.- W. Ferrel—Law of Thermal Radiation., 27 ture of the sun as deduced from (86) with the value of ¢ in (23). And this expression, with the constants used, represents observation fairly well throughout the whole range of experi- ment with lampblack and bare glass radiating surfaces, while the others do not, especially that of Dulong and Petit’s law. But this temperature, as well as that of Pouillet’s from Dulong and Petit’s law, is doubtless much too low. And this is not surprising, for it has not been claimed or supposed that this new law, although it represents observation better throughout the short range of experiment of only about 240°, can be ex- tended with safety up to the high temperature of the sun. The scattering results obtained indicate that no reliability can be piaced in such methods, to show which has been the princi- pal object in touching upon this part of the subject here. 25. According to Langley’s deductions from his experiments at the Edgar Thompson steel works near Pittsburg,* solar heat radiation is about 100 times greater than that of melted iron at a temperature of at least 1800°, angular area for area. Sup- posing both to have the same relative radiativities we could arrive at the sun’s temperature if we knew the law of the increase of radiation with increase of temperature from this up to the sun’s temperature. We have seen that none of the pre- ceding laws can be relied npon for this purpose, though they of course would give better results by starting at the high temperature of 1800° than in commencing down at ordinary temperatures and extending them through a range 1800° greater. Using Dulong and Petit’s law we would have ; 1:00777=100 x 1:0077" - as the condition for determining the solar temperature 7c, 7’ being equal to 1800°. The solution of this gives t=2400°. As this law gives results demonstrably too small, this is, no doubt, too small, but much more nearly correct than that of Pouillet’s obtained by extending the law through a much greater range of temperature. By Stefan’s law we should have Ai OOM The solution of this, putting T’=1800+273=2073, gives T=6555° or t=6282° for the sun’s temperature. This does not differ greatly from the preceding value of t as obtained by Stefan’s law from (86). With the exponent equal to 4:2, which, we have found, satisfies observation better, we get T=5933°. These last results are undoubtedly much better, as obtained from these data, than that obtained with Dulong and Petit’s law, which, we have reason to think, is very erroneous for high temperatures. If the “100 times” in the comparison * Proc. of the Am, Academy of Arts and Sciences, 1878. 28 W. Ferrel—Law of Thermal Radiation. . above refers to the sun’s heat-radiation as it reaches the earth’s surface, as seems to be the case, then the numerical coefficient in the conditions above should be increased at least one-third for the loss in passing through the atmosphere, the effect of which would be to increase considerably the preceding com- puted temperatures. 26. The condition which determines the temperature at. which a body in space at the distance of the earth from the sun would stand from the effect of the sun’s thermal radia- tion, is (37) H=1—A ) Qa in which H, as in the case of (34), is a function of the tempera- ture of the form of (1), (6), etc., according to the assumed law, and in which d and a are the relative radiativities and absorp- tivities of the body with reference to lampblack, supposed to be a perfect absorber. In a lampblack surface, as that of a black-bulb thermometer, or any one in which there is no selec- tive absorption and radiation, but all the wave-lengths are radiated in the same proportions as those of a lampblack sur- face, we have 0/a2=1 in the resultant of the radiations and absorptions of all wave-lengths. By means of (1) we get from (37) EME CAO) (38) mat =7—A as the condition for determining the temperature z of the body. But here, as in the preceding case with regard to the sun’s temperature, the uncertainty in the true value of m comes in, but not so much that of the other part of the law, since we have here to deal with temperatures differing but little from those of the experiments upon which the law is based, and so have to extend the law through a small range only of temperature. Dulong and Petit’s value of a has been shown to be too small and Pouillet’s value of m too large for ordinary temperatures of the earth’s surface. Taking, there- fore, the value of a=1-:0082 as given at the head of the last column but one of the table of § 4, which has been found best to satisfy the results of experiment as corrected by Stefan, and the value of m=0'7188 in § 7, and putting A=2°2, as heretofore, the preceding equation, (38), gives in any case in which d/a=1, T=—33° as the temperature at which the body would stand, as determined from the preceding condition with the assumed value of the constants, and as the mean temperature of the earth and moon if their surfaces satisfied the conditions above with regard to radiation and absorption. C. D. Walcott—Position of the Olenellus Fauna. 29 If we adopt the value of m=0°652 and value of a=1-:0088 in (29), which have been shown to be probably more nearly correct values for low temperatures, we get t=—19°. With a larger value of the solar constant these temperatures denoted by t would be higher. By means of (6) we get from (37) (39) m—=}—A The most probable values of m and e for low temperatures are that of § 20, m=0°438, for the former, and that of equation (23) for the latter, though the value of m here deduced from the radiation of glass at high temperatures should be increased a little for a lampblack surface. With these values (39) gives T=291° or t=18°, which is a little above the mean tempera- ture of the earth’s surface. The values of m deduced from experiments at high temperatures, by Dulong and Petit’s law and the values by Stefan’s law are found to differ very much, the former being the greater, and the same is true with regard to any modification of these laws, by giving different values to the constants a and e in the general expressions of (1) and (6), but in deducing the values of a and ¢ from experiments at lower temperatures we find that the corresponding values of m decrease in the former case and increase in the latter, so that the tendency is to bring them nearer together. The true value, no doubt, lies somewhere between, but to determine it with greater accuracy it is important to have experiments upon radiation at much lower temperatures than those of any experi- ments yet made. Art. I1.—Stratigraphic Position of the Olenellus Fauna in North America and EHurope ; by CHARLES D. W ALcoTT, of the U. 8S. Geological Survey. (Continued from page 392, vol. xxxvii.) SINCE the first part of this article was written the review of all the species known to me from the Lower Cambrian or Olenellus zone in North America has been completed. To the list published (ante, pp. 388, 389) there are to be added the genera Nothozoe, Modioloides and Straparollina, and the species Lingulella, sp. undet., Camerella minor, n. sp., Lamelli- branch, gen. and sp. ? (Shaler and Foerste), Scenella, sp. undet., Straparollina remota Billings, Mothozoe? Vermontana and Olenoides quadriceps H. & W. Paradoxides ? Walcotti is referred to Olenellus and Modiolopsis (??) prisca to Modio- 30 C. D. Walcott—Position of the Olenellus Fauna. loides, n. gen. The entire fauna from America now includes 57 genera, 134 species and 10 varieties. Relations of the Lower Cambrian to the Middle Cambrian Fauna.—tIin the Atlantic Province the two faunas are respec- tively called Olenellus and Paradoxides, from the most typical genera of trilobites occurring in them. In the Cambrian sec- tions of the Rocky Mountain or Pacific Province and the Appalachian Province there is a Middle Cambrian fauna, more or less distinctly defined, but it is not the typical Paradoxides fauna of the Atlantic Province. On this account the Middle Cambrian fauna of the Atlantic Province will be spoken of as such, or as the Paradoxides fauna; and the term Middle Cam- brian will be used when other portions, or the entire fauna of the Middle Cambrian are referred to. Physical or Stratigraphic Relations.—The Cambrian sec- tion, on Manuel’s Brook, shows a continuous deposition of sedi- ments, from the basal conglomerate through Lower Cambrian (Olenellus zone) time to and through Middle Cambrian (Para- doxides zone) time; a thickness of about 250 feet of shale having been deposited between the typical Olenellus zone and the Paradoxides zone. The same conditions of continuous and conformable sedimentation appear to have prevailed on the eastern side of the Atlantic Province in Sweden and Norway. The great conformable sections of Cambrian strata in the Rocky Mountain Province do not show any break in the sedi- mentation between the Lower, Middle, and Upper Cambrian strata, except near the eastern shore line, as in the Wasatch section of Utah, where strata of Upper Cambrian age were not deposited. In Russia, Britain, Spain, Sardinia, and on the western side of the Atlantic, in New Brunswick and Massachusetts, the stratigraphic relations of the faunas are not exhibited; and in the St. Lawrence and Appalachian regions of America the data are wanting by which to place the faunas stratigraphically in any one, unbroken section. As far as known the physical relations of the faunas do not furnish sufficient reason to account for the change from the Olenellus to the Middle Cambrian fauna; and there is no recognized unconformity indicative of a physical break and a consequent time interruption in the deposition of the sediments forming the strata between the two faunas. Loological felations.—Under this head will be mentioned (1) the species that range from the Lower Cambrian into the Middle Cambrian, in each typical province of the Olenellus fauna; (2) the relation of the genera and species, irrespective of geographic distribution and vertical range; (8) the com- parison of the faunas as a whole. C. D. Walcott— Position of the Olenellus Fauna. 31 I. New York and Vermont.—The Olenellus fauna appears to have a great vertical range in New York, as shown by the Cambrian strata of Washington and Rensselaer counties. I have called it 14,000 feet,* but this may be modified by a more detailed study of the sections. About 2,000 feet from the summit of the strata assigned to the Cambrian, the fauna con- tains Olenellus asaphoides but with it occurs the species Lin- gulella Granvillensis, Linnarssonia sagittalis var. Taconica, Agnostus desiderata, Agnostus of the type of A. pisiformis, Nicrodiscus connexus and Zacanthoides Hatoni, all of which are representative species of the Paradoxides fauna. Professor W. B. Dwight has recently permitted me to examine the type specimens of Olenoides Stissingensis Dwight, Leperditia ebinina Dwight, and Kutorgina Stissingensis Dwight, from the Middle Cambrian strata of Dutchess County, New York. None of these species occur in the Olenellus fauna, and the Olenoides belongs to the type of the genus occurring in the Middle Cambrian rocks of Utah. Mutorgina Stissingensis is the representative of Autorgina Labradorica of the Lower Cambrian, and Leperditia ebinina belongs to a division of the fo that includes a similar type, from a bed referred to the iddle Cambrian, in the Grand Cafion section in Arizona. These species indicate that the Middle Cambrian fauna of eastern New York has the general facies of that of the Southern Appalachian and Rocky Mountain provinces. In the Georgia section of Northern Vermont the Olenellus zone has a thickness of about 500 feet.t With the possible exception of Ptychoparia Adamsi none of the species are known to range upward in the section. Rocky Mountain Area.—In the Rocky Mountain area the Eureka District and Highland Range sections show the rela- tions of the Lower, Middle and Upper Cambrian faunas.t In each section the Olenellus fauna is confined to a comparatively narrow zone, just above the non-fossiliferous quartzite. In the Eureka District the fauna consists of but six species : Kutorgina Prospectensis, Scenella conula, Olenoides quadri- ceps, Olenellus Gilberti, O. Iddingst and Anomocare parvum. Of these, two species, Olenoides quadriceps and WScenella conula, are found 500 feet higher in the section.$ The Olenellus fauna, in the Highland Range section, in- cludes only Olenellus Gulberti and O. Iddingsi.| One hun- dred feet higher in the section Hyolithes Bilkingsi is found, just as in the Eureka section, Stenotheca elongata oceurs 2,000 * This Journal, III, vol. xxxv, 1888, p. 242. ¢ Bull. U. 8. Geol. Survey, No. 30, 1886, pp. 15-20. ¢ Bull. U. 8. Geol. Survey, No. 30, 1886, Introduction. § Op. cit., p. 32. | Op. cit., pp. 33, 34. 32. «C.D. Walcott—Position of the Olenellus Fauna. feet above the Olenellus zone, although a Lower Cambrian species in the Atlantic Province. In the Pioche section * the fauna of the Olenellus zone is larger. It includes Locystites ?? longidactylus ? Lingulella Ella, Kutorgina pannula, Acrothele subsidua, Acrotreta gemma, Orthis Highlandensis, Hyolithes Billingsi, Olenellus Gilberti, Olenoides levis, Crepicephalus Augusta and C. Lili- ana. Of these Hocystites ?? longidactylus is very doubtfully identified by single plates; Autorgina panula, Acrothele sub- sidua, Acrotreta gemma and Hyolithes Billings: pass to the zone above or that carrying Olenellus. In the Wasatch section of Utah Olenellus Gilberti oceurs in a narrow band of arenaceous shale that is subjacent to silico- argillaceous shales, containing a number of species that I form- erly referred to the Olenellus fauna. Restricting the fauna to only those species occurring in association with Olenellus or a grouping of species characteristic of the Olenellus zone, where Olenellus is present, all the species, with the exception of Olenellus Gilberti and Cruziana sp.?, are referred to the Middle Cambrian fauna. In the section of Mount Stephen and Castle Mountain, in British Columbia, Mr. McConnell+ found the Olenellus fauna at the base of the Castle Mountain limestone; beneath it there are dark-colored argillites and sandstones, estimated at over 10,000 feet in thickness, which correspond in position and character to the pre-Olenellus strata of the Wasatch section, which are referred to the Algonkian Period. In the collection made by Mr. McConnell from the Olenellus zone there are Olenellus sp.?, Ptychoparia Adamsi and Protypus senectus. The fauna of the Middle Cambrian zone is 2,000 feet higher in the section and includes in the collection made by Dr. Rominger: Sponge ? HHyolithellus. Lingulella Me Connelli (sp.) Agnostus interstrictus White. Crania? Columbiana Walcott. | Karlia Stephenensis White. Linnarssonia, like L. sagittalis.| Olenoides Nevadensis Meek. Acrotreta gemma var. depressa| Zacanthoides spinosus Walcott. Walcott. Bathyuriscus Howelli Walcott. Kutorgina pannula White. Bathyuriscus (Kootenia) Daw- Orthis sp.? sont Walcott. Orthisina Alberta Walcott. Ogygopsis Klotzi Rominger. Scenella conula Walcott. Ptychoparia Cordillerce Romin- Platyceras Romingera Walcott.| ger. * Op. cit.. p. 35. + Geol. and Nat. Hist. Survey Canada, Ann. Rept. new ser., vol. 1, 1887; Rept. Geol. Structure of a portion of the Rocky Mountains, p. 29 D. .D. Waleott—Position of the Olenellus Fauna. 38 The slender Hyolithellus is much like 4H. micans of the Olenellus fauna, but, in the absence of the characteristic oper- culum, it does not seem best to identify it as the same species. As known at present six species only pass from the Olenel- Ius zone to the ee strata, in the Rocky Mountain province. They are: Autorgina pannula, Acrothele subsidua, Acrotreta gemma, Scenella connula, Hyolithes Billingst and Olenoides quadriceps. Of these Acrotreta gemma extends up to the Upper Cambrian zone, in Montana. Newfoundland.—The fauna of the Olenellus zone contains but one species that ranges up into the Paradoxides zone— Hyolithes princeps. Agraulos strenuus is closely allied to Agraulos socialis of the Paradoxides fauna, and Platyceras primevum is very like P. minutissima of the Upper Cam-. brian. The review of the sections shows but little specific relation- ship between the two faunas, as only nine species are now known to range from zone to zone. A review of the genera shows a large percentage common to the two zones. _Of the 68 genera of the Olenellus zone 47 pass up into the Middle Cambrian. The genera confined to the Lower Cambrian, in America, are : Leptomitus. Coleoloides. Protopharetra. Hyolithellus ? Spirocyathus. Protocaris. Coscinocyathus. Olenellus. Ethmophyllum. Bathynotus. Modioloides. Avalonia. Fordilla. Oryctocephalus. Helenia. - Protypus. Of the European genera, the following five : Mickwitzia. Medusites ? Volborthella. Frena, Platysonites. are referred only to the Lower Cambrian. Il. Relations of the Genera and Species of the Lower and Middle Cambrian—The comparison between the two sub- faunas will be made by considering the genera and species of each class of the Lower Cambrian and comparing it with the same class of the Middle Cambrian fauna. Algew.—As far as known to me, there are no true Algze in the rocks of the Lower Cambrian. That such forms existed, there can scarcely be any doubt, but after a study of all of the reported species, I think that they can be referred to trails of AM. JOUR. SoL— THIRD SERIES, VoL. XXXVIII, No. 223.—JuLy, 1889. 34. CO. D. Walcott—Position of the Olenellus Fauna. worms or mollusks with much more propriety than to the Algze. Specimens of Cruziana, collected in Newfoundland, lead me to think that it is a trail or burrow and not an Alga. No traces of land vegetation have been discovered in the rocks of the Cambrian Period. Spongie.—The sponges of the Lower Cambrian are limited to two genera, of which one, Protospongia, is found in the upper beds of the Olenellus zone of the Atlantic Province, and also in the Middle Cambrian in Nevada, New Brunswick, Newfoundland, Wales and Sweden. Leptomitus is confined to the Lower Cambrian. Hydrozoa.—lt is to the researches of Dr. A. G. Nathorst that we owe a knowledge of the occurrence of Medusz in the Lower Cambrian rocks of Sweden. By a series of compari- sons between the casts found in the rocks at Lugnas and the casts made by the impressions of recent Medusee, more espe- cially of Aurelia aurita and Cyrena capillata, he has shown that it is extremely probable, if not certain, that the delicately constructed Medusve lived during the Lower Cambrian epoch and left traces of their existence in the clays and sands of the seashore. Dr. Nathorst figures and describes* J/edusites Lind- stromi Linnrs., JZ. favosus Nathorst and JZ. radiata Linnrs., and states that he thinks the so-called species of Eophyton are the casts of trails made by the Meduse in moving along the sea bed. There are, in the collections of the United States Geological Survey, a group of forms from the middle part of the Cambrian in Alabama, that appear to be generically related to J/edusites Lindstrom. They will be described with the description of the Middle and Upper Cambrian fauna. In ascending the geological series, it is not until the lithographic slate of the Upper Jura, at Solenhofen, ete., is reached, that traces of the Medusz are again met with. The Graptolitidee are represented by two species that are pro- visionally referred to the genera Phyllograptus and Climaco- graptus. These generic types are not met with again until the base of the Ordovician is reached, where they are largely devel- oped. Mr. Matthew has described two species of graptolites from the Middle Cambrian of New Brunswick, which he refers to Dendrograptus and Protograptus. Actinozoa.—It has been an open question for some years whether the forms referred to the genus Archeocyathus were corals or sponges. Dr. G. J. Hinde has recently reviewed the genera and species, and concluded that they form a special family of the Zoantharia sclerodermata, in some features allied to the * Kongl. Svenska Vetenskaps-Akademiens Handlingar, Bandet 19, N. 1, 1881. Om Aftryck af Medusor i Sveriges Kambriska Lager. C. D. Walcott—Position of the Olenellus Fauna. 35 group of perforated corals. A re-study of all the species and a personal examination of Dr. Hinde’s specimens leads me to agree with him that they should be referred to the Actinozoa. With the exception of the single doubtful species of Archee- ° ocyathus, described by Mr. Matthew, from the Paradoxides zone of St. John, N. B., A. ? pavonordes, there are no repre- sentatives of this family (Archeeocyathine) in the later Cam- brian. The first true corals met with in the ascending series occur near the base of the Ordovician. Echinodermata.—The Echinodermata are represented by a few scattered plates of a species of Cystid, which is referred provisionally to the genus Eocystites. It is impossible to make any comparison between it and the Cystids of the Middle Cambrian. Annelida, etc—The trails, burrows and tracks of animals, that occur in the Lower Cambrian, are nearly all duplicated in the Upper Cambrian. This is true of the genera Planolites, Helminthoidichnites, Scolithus and Cruziana, of the American rocks. As far as determined by traces left by their passage the same type of animals existed throughout the Cambrian. Brachiopoda.—The Brachiopoda, with 10 genera and 29 species, afford a much broader opportunity for comparison, but even here the specific connection is very slight between the two zones. Of the genera, Lingulella is represented in the Paradoxides zone by a group of forms that have received the names L. Linguloides and L. Dawsoni, in New Brunswick ; Lnngulella sp., in Linnarsson’s Brachiopoda of the Paradoxides beds of Sweden (Plate III, figs. 24-28), and LZ. Granvillensis, in the Olenellus zone of New York. The species of the genus Acrotreta, of the Paradoxides zone of Sweden and New Bruns- wick and the Middle Cambrian zone of the Rocky Mountain Province, are so closely allied to the species from the Olenellus zone in Nevada that we consider that one species, A. gemma, ranges from the base of the Cambrian through to the Upper Cambrian. ) |e Manganous oxide _.-__-_---- MSY Ui eae Pe trace +) 52 osama STE Tan OG lah es ag AORN ES ae | 9°20 4.38 340 11-47 Macnesiaena cee = faa seer aoe | 13°17 6°37 2°18 12°31 RSTO 0 Fs), ee a ES Sl ee Ly) hy 2°73 1°60 3°10 3°37 Potashwayte eco sic ee | 217 10°73 | 5:37 4:42 GHIGTING 5.2 sae see te Asean Weeasieees aes ae sate 23 5s4| eee Phosphorictacidy sss see ee- “DON AE aed eee | 9), 71 ce eeean Carbonichaci dias sam = eee [stators vate ci 1:82) ee NAVEEN Re) og See roast ae We ma NUE | 2:96 2°76 TOs nice ee eee 100°08 IGESSuOmt Orn tesa eee eee “O4 Rotaleas Bee sey ae 100°04 99°58 100°78 99°62 No. 1, Ishawooa Cation, Wyoming Territory ; No. 2, Cerro de las Virginas, Lower California ; No. 3, Leucite hills, Wyoming Territory ; No. 4, Bongsberg, near Pelm in the Kifel. The analysis of the bowlder from Ishawooa Cafion shows a somewhat exceptional magma and affords astriking example of a rock whose chemical composition gives but sight indication of its mineral composition. No one would be led to suspect the presence of leucite in a rock carrying so low a percentage of alkalies. In most rocks characterized by the presence of leucite, the mineral has erystallized out of a strongly alkaline magma, and one in which potash is usually considerably in excess of the soda as shown in the Vesuvian lavas and those from the Leucite Hills. In the case of the Ishawooa rock the soda and potash taken together only sum up about five per cent of alkali with soda in excess of the potash The amount of magnesia present is exceptionally high with a correspondingly low amount of alumina, in this respect quite unlike the Vesuvian leucite-basalts. It is evident from a study of this olivine-leucite-phonolite that the olivine, augite, magnetite and apatite were the product of the first generation of crystals and were developed out of the magma before the crystal- lization of the orthoclase and leucite. Now by removing from the original magma the material required for the earlier crys- tallization there would remain a magma carrying in a more con- centrated form the greater part of the alkalies, which as shown by the second generation of crystals, was more favorable for the development of orthoclase and leucite. It is a marked instance of the potassium and sodium silicates being the last to solidify. Under different conditions of crystallization a mineral development quite at variance with that found in this rock M. Carey Lea—Allotropice forms of Silver. 47 may possibly have been produced from the same original magma. At some future time the locality will be revisited with the expectation of finding the rock in place and exposed in a way to permit of the study of any modifications of structure the rock mass may undergo. It will, I think, be found to occur as one of the intrusive dikes cutting the earlier andesitic lava sheets and broad fields of breccias. Ishawooa Canon lies north of the Leucite hills about 150 miles, the geological conditions bemg quite different from those surrounding the earlier known locality. In columns 2 and 3 of the table will be found analyses from the two other American localities of leucite-bearing rocks. In column 4 of the table the analysis of a leucite-basalt from the Eifel, described by Hussak, is given for the purposes of com- parison, it corresponding more closely in chemical composition to the Ishawooa rock than any other published analysis. It is, however, like most leucite rocks, richer in alkalies with potash in excess of the soda. Art. V.—On Allotropic Forms of Silver ; by M. Carry La. [Continued from page 491, vol. xxxvii.| In the first part of this paper were described certain forms of silver; among them a lilac-blue substance, very soluble in water with a deep red color. After undergoing purification it was shown to be nearly pure silver. During the purification by washing it seemed to change somewhat, and consequently some uncertainty existed as to whether or not the purified sub- stance was essentially the same as the first product: it seemed possible that the extreme solubility of the product in its first condition might be due to a combination in some way with citric acid, the acid separating during the washing. Many at- tempts were made to get a decisive indication and two series of analyses, one a long one, to determine the ratio between the silver and the citric acid present, without obtaining a wholly satisfactory result, inasmuch as even these determinations of mere ratio involved a certain degree of previous purification which might have caused a separation. This question has since been settled in an extremely simple way, and the fact established that the soluble blue substance contains not a trace of combined citric acid. The precipitated lilac-blue substance (obtained by reducing silver citrate by ferrous citrate) was thrown on a filter and cleared of mother water as far as possible with a filter pump. 48 Allotropie forms of Silver. Pure water was then poured on in successive portions until more than half the substance was dissolved. The residue, evi- dently quite unchanged, was of course tolerably free from mother water. It was found that by evaporating it to dryness over a water bath, most of the silver separated out as bright white normal silver; by adding water and evaporating a second time, the separ ation was complete and water added dis- solved no silver. Zhe solution thus obtained was neutral. lt must have been acid had any citric acid been combined origi- nally with the silver. This experiment, repeated with every precaution, seems conclusive. ‘The ferrous solution, used for reducing the silver citrate had been brought to exact ‘neutr ality with sodium hydroxide. After the reduction had been effected the mother water over the lilac-blue precipitate was neutral or faintly acid. A corroborating indication is the following. The portions of the lilac-blue substance which were dissolved on the filter (see above) were received into a dilute solution of magnesium sulphate, which throws down insoluble allotropic silver of the form I have called B, (see previous paper.) This form has already been shown to be nearly pure silver. The magnesia solution, neutral before use was also neutral after it had effected the precipitation, indicating that no citric acid had been set free in the precipitation of the silver. It seems therefore clear that the lilac-blue substance contains no combined citric acid. Had the solubility of the silver been due to combination with either acid or alkali, the liquid from which it was separated by digestion at or below 100° C. must have been acid or alkaline; it could not have been neutral. We have therefore this alternative. In the lilac-blue sub- stance we have, either pure silver in a soluble form, or else a compound of silver with a perfectly neutral substance generated from citric acid in the reaction which leads to the formation of the lilae-blue substance. If this last should prove the true ex- planation, then we have to do with a combination of silver of a quite different nature from any silver compounds hitherto known. A neutral substance generated from citric acid must have one or more atoms of hydrogen replaced by silver. This possibility recalls the recent observations of Ballo, who by act- ing with a ferrous salt on tartaric acid, obtained a neutral colloid substance having the constitution of arabin, C,H,,O,,. To appreciate the difficulty of arriving at a correct conclu- sion, it must be remembered that the silver precipitate is ob- tained saturated with strong solutions of ferric and ferrous citrate, sodinm citrate, sulphate, ete. These cannot be removed by washing with pure water, in which the substance itself is very soluble, but must be wot rid of by washing with saline M. Carey Lea—Allotropic forms of Silver. | 48) solutions, under the influence of which the substance itself slowly but continually changes. Next, the saline solution used for washing must be removed by alcohol. During this treat- ment, the substance, at first very soluble, gradually loses its solubility and when ready for analysis, has become wholly insoluble. It is impossible at present to say whether it may not have undergone other change: this is a matter as to which I hope to speak more positively later. It is to be remarked, however, that these allotropic forms of silver acquire and lose solubility from very slight causes, as an instance of which may be mentioned, the ease with which the insoluble form B re- covers its solubility under the influence of sodium sulphate and borate and other salts as described in the previous part of this paper. The two insoluble forms of allotropic silver which I have described as Band ©; B, bluish green, © rich golden color, show the following curious reaction. A film of B, spread on glass and heated in a water stove to 100° C. for a few minutes becomes superficially bright yellow. A similar film of the gold-colored substance C treated in the same way, acquires a blue bloom. In both cases it is the surface only that changes. Sensitiveness to Light.—All these forms of silver are acted upon by light. A and B acquire a brownish tinge by some hours’ exposure to sunlight. With C the case is quite different, the color changes from that of red gold to that of pure yellow gold. The experiment is an interesting one, the exposed portion retains its full metallic brillianey, giving an additional proof that the color depends upon molecular arrangement, and this with the allotropic forms of silver is subject to change from almost any influence. Stability.—These substances vary greatly in stability under influences difficult to appreciate. I have two specimens of the gold yellow substance C, both made in Dec. 1886, with the same proportions, under the same conditions. One has passed to dazzling white, normal silver, without falling to powder, or undergoing disaggregation of any sort; the fragments have retained their shape, simply changing to a pure frosted white, remaining apparently as solid as before, the other is unchanged and still shows its deep yellow color, and golden luster. An- other specimen made within a few months and supposed to be. permanent has changed to brown. Complete exclusion of air and light is certainly favorable to permanence. Physical condition.—The brittleness of the substances B and C, the facility with which they can be reduced to the finest powder, makes a striking point of difference between allotropic Am, Jour. me Series, Vout. XXXVIII, No. 223.—Juny, 1889. 50 = Branner and Brackett—Peridotite of Arkansas. and normal silver. It is probable that normal silver, precipi- tated in fine powder and set aside moist to dry gradually, may cohere into brittle lumps, but these would be mere agerega- tions of discontinuous material. With allotropic silver the case is very different, the particles dry in optical contact with each other, the surfaces are brilliant and the material evidently continuous. That this should be brittle indicates a totally different state of molecular constitution from that of normal silver. Specific Gravities.—The allotropic forms of silver show a lower specific gravity than that of normal silver. In determining the specific gravities it was found essential to keep the sp. gr. bottle after placing the material in it for some hours under the bell of an air pump. Films of air attach themselves obstinately to the surfaces and escape but slowly even in vacuo. Taken with this precaution, the blue substance B gave spe- cific gravity 9°58 and the yellow substance C, sp. gr. 8°51. The specitic gravity of normal silver, after melting was found by G. Rose to be 10°5. That of finely divided silver obtained by precipitation is stated to be 10°62.* I believe these determinations to be exact for the specimens employed. But the condition of aggregation may not improb- ably vary somewhat in different specimens. It seems however clear that these forms of silver have a lower specific gravity than the normal, and this is what would be expected. Chestnut Hill, Philadelphia, May, 1889. Art. 1V.—The Peridotite of Pike County, Arkansas ; by JOHN C. BRANNER, State Geologist of Arkansas, and Ricuarp N. BRAcKETT, Chemist of the Geological Survey of Arkansas. With Plate I. Part I, by John C. Branner. Two and a half miles southeast of Murfreesboro in Pike county, Arkansas, is a small exposure of peridotite whose posi- tion and topographic features are shown in detail upon the accompanying map (Plate I.) The entire exposure is about 2400 feet long by 1600 feet wide, and lies upon the middle of the line between sections 21 and 28 of township 8 south, range 25 west. From a geological standpoint this exposure is an important one, for, small as it is, it offers a eae regarding the time and character of the disturbing influences, which, about the * Watts’ Dict., orig. ed., v, 277. Branner and Brackett—Peridotite of Arkansas. 51 close of the Cretaceous, sank the greater part of Arkansas as well as the large Tertiary-covered portions of the neighboring states beneath the ocean. It is important, also, from a petro- graphic standpoint as being the third reported occurrence of picrite-porphyry in the United States. With the accompanying map and section before the reader, it will not be necessary to give a detailed description of the locality. It was first reported by Dr. Owen in his ‘‘Second Geological Report,” p. 32, but was not studied by him in detail, and the rock is simply spoken of by him as a “ porphy- ritic greenstone” and a ‘“‘trachytic rock.’’ Since Dr. Owen’s time no one seems to have made any observations upon it. Some of the geological maps that have, from time to time, been published of the United States, have represented in this place a large Archean area. The rock presents no great variety in lithologic characters, and the specimens examined microscopically by Dr. Brackett, and described by him in the second part of this paper, fairly represent them, except that in many places through the general mass it contains a good many angular and sub-angular inclusions of crystalline rock, which are especially noticeable wherever the rock is deeply decom- posed, and that one small dyke coming up through the Meso- zoic beds contains a vast quantity of fragments of Paleozoic sandstone and shale and of soft sandstone and quartz pebbles from the Mesozoic. Only in the three hills shown upon the map, and in the one very small dyke is the rock found solid, disintegration having gone so far in the lower grounds that it there occurs only in the form of a soft earthy wacke, which washes very readily into deep gullies. This earth, where freshest and unmixed with organic matter, presents many beautiful shades of green, brown, red, and gray colors. At one point a dyke is uncovered in one of these gullies. This dyke is about six feet wide, runs east-west, and in place of the olive-green color so characteristic of the general mass, it is of a beautiful bright blue color. It is so deeply decomposed that no solid specimens could be had from it. On the summit and sides of the central hill the rock mass is broken into large blocks, which, by concentric disintegration and exfoliation, are left in the form of bowlders of various sizes. If the overlying Post-tertiary and Quaternary debris could be removed in the immediate vicinity of this exposure, it is probable that the area of igneous rocks, as shown upon the accompanying map, would be somewhat enlarged, at least by disclosing dykes radiating from the central mass. There is no reason for supposing, however, that the Post-tertiary obscures any great area of peridotite. There are no exposures of it in Prairie creek, except a single small dyke not more than ten 52 = Branner and Brackett—Peridotite of Arkansas. inches wide and about fifty feet long, while a deep gully on the north side of the outburst (Poor House branch on the map), shows no expostires. East of the exposure, at the house of Mr. McBrayer (shown upon the accompanying map), a well recently. dug to a depth of 162 feet penetrated only the clay, cobble stones and soft calcareous beds, such as characterize the Post-tertiary and lower Cretaceous in this region. The following is the section of Mr. McBrayer’s well: TOG CV aiy,s sais s ee ate tas Se Quaternary and recent. 10’ Cobbles and pebbles__Post-tertiary. 142’ Soft arenaceous clays and calcareous beds ; Lower Cretaceous (“Trinity” of variously colored. Hill). These facts appear to indicate that the outburst was confined to this very circumscribed area, there being no eastward exten- sion of it at the depth reached in McBrayer’s well—162 feet below the level of his house—and but one westward exposure uncovered at the mouth of Prarie creek. Relations of the igneous to the sedimentary rock.— Besides this peridotite, the rocks exposed in this part of Arkansas are of Paleozoic, Lower Cretaceous (“ Trinity” of Hill), Post-ter- tiary and Quaternary ages. The Paleozoic rocks form the high lands of the hilly and mountainous region of the state lying north of the Neozoic exposures. They are made up of alter- nations of sandstones and shales, and are highly flexed, the axes of the folds varying but little from due east and west. Just north of Murfreesboro, and four miles from the exposure of peridotite, these sandstones and shales have a high south dip, at many places standing almost or quite vertical. These south dips continue for many miles to the north, a section measured dcross the beds farther east showing an aggregate vertical thick- ness of strata of at least four miles. Against and upon the eroded, upturned edges of these Carboniferous rocks the lower Cretaceous beds have been deposited. The rocks of the Cre- taceous are soft sandstones, shales, lignites, clays, ete., all beau- tifully variegated, the predominating colors being straw, lead, pink, and terra cotta, and the beds exhibit a low and almost imperceptible dip to the east and southeast.* The Little Missouri River and its predecessor, flowing along the original inland margin of the Cretaceous, have here cut out a valley five miles wide, its right and southern wall being a * Through the kindness of the Director of the U.S. Geological Survey, Prof. R. T. Hill spent the past year in studying the Mesozoic geology of Arkansas. His report is already completed and forms Vol. II of the annual report of the Geological Survey of Arkansas for 1888. In this report, Prof. Hill shows that the Mesozoic rocks in the vicinity of this exposure belong to what he calls the Trinity, which he thinks is equivalent of the Wealden of Europe. ‘ Branner and Brackett—Peridotite of Arkansas. 53 line of nearly vertical Cretaceous clifis, which are the attacked northern edges of these beds; the left or northern border is formed by the Paleozoic highlands, while the bottom of the valley is in lower Cretaceous beds covered by Post-tertiary debris and by Quaternary and recent sediments. It is in this plain that the exposure of peridotite occurs. The accompany- ing section shows the relations of the intruded rocks to those of sedimentary origin. Section through the Pike County Peridotite and the adjacent Formations. I. River silt. IV. Lower Cretaceous (‘‘ Trinity” of Hill). II. Yellow loam. V. Paleozoic (lower Carboniferous ?) Ill. Post-tertiary. xX. Peridotite. (The relations shown in this section, with the exception of the exact contact of the Paleozoic with the igneous rocks, may all be séen, though not at any one exposure.) The contact between the Paleozoic and the Cretaceous is exposed in Prairie creek about two miles northeast of Mur- freesborough where the Cretaceous rock is a conglomerate with caleareous cement. These parti-colored Cretaceous beds are cut into and exposed in many places, and at low water almost continuously, along Prairie creek from this point to the mouth of the stream, while on the right bank of the Little Missouri they rise in beautifully exposed cliffs to a height of nearly one hundred feet above the river. Where Prairie creek enters the Little Missouri, a dyke of peridotite not more than ten inches wide stands out for fifty feet across the mouth of the former stream, and on the left bank of the river this dyke is seen to penetrate the soft sand- stones of the lower Cretaceous. Where the Cretaceous has been cut away by Post-tertiary erosion and covered with the water-worn debris, the dyke is also cut off even with the eroded Cretaceous surface and covered with debris. At the line of contact between the dyke and the Cretaceous sandstone, the most careful microscopic examination does not reveal the slightest trace of metamorphism. The original material injected into this crevice is so thoroughly filled with the debris of the beds through which it has passed—shales, sandstones and quartz pebbles—that their included fragments form about two-thirds 54 Branner and Brackett— Peridotite of Arkansas. of the dyke as it now stands. Even the soft inclusions from the Cretaceous are unaffected. The great number of these inclusions suggest that the injected mass was cooled by them to such an extent that it was rendered incapable of producing contact metamorphism even on a very small scale. The horizontally bedded Cretaceous strata do not appear to be disturbed in any way whatever by the presence of this dyke or even by that of the main body of peridotite. This little dyke affords the principal evidence in regard to the age of these igne- ous rocks. The Paleozoic exposure at this locality is the most southerly one known in the state. The rocks are all sandstones or quartz- ites, frequently false-bedded, and contain many so-called “‘ fucoid impressions.” ‘They are much fractured and jointed and occur, for the most part, as irregular and angular blocks, and only at the extreme southwest part of the exposure is it possible to de- termine their dip satisfactorily. The dip moreover is not uni- form either in amount or direction, the one measured being 26° southwest, and somewhat below the average. The exact contact between the Paleozoic and the igneous rock is not visible. The rocks of this group vary considerably from flinty green- ish quartzites to light-colored and porous sandstones, but this variation is no greater than one might expect to find in the var- jable sandstones of the Lower Carboniferous to which these are supposed to belong. Some of the quartzites are extremely hard, but the appearance of freshly broken specimens shows that this hardness is to be attributed to the indurating effects of weather- ing, rather than to contact metamorphism. In some instances the sandstones are of a light brown color and contain traces of vegetable matter, though no recognizable forms have thus far been discovered. In other cases they are tinged with green coloring matter, probably due to the presence of chlorite. Inasmuch as it has been suggested that the South African diamonds may have been generated by the metamorphism of the carbon in the carbonaceous shales penetrated by peridotite, I should add that no such phenomenon is suggested by obser- vations at this locality or upon these rocks. The Post-tertiary wash so widespread in southwestern Arkan- sas is thinly scattered about the foot of the ridge of peridotite. Its cobbles and pebbles are of sandstone, quartz, novaculite, and jasper, cemented here and there into a ferruginous con- glomerate. The fragments are usually much water-worn, but some of them are subangular, while in size they range from that of one’s head downward. Careful search was made among this material for fragments of peridotite or serpentine, but none was found. From the readiness with which this rock decom- Branner and Brackett—Peridotite of Arkansas. 5D poses, however, it could hardly be expected that such fragments would be preserved for any great length of time. The sum of our evidence favors the hypothesis that this per- idotite is a simple injection which took place about the close of the Cretaceous through and between the Paleozoic strata, and penetrating the lower Cretaceous beds, and that whatever its relations to orographic movements may have been, it caused no great direct disturbance either chemical or physical in the beds with which it appears in contact. It naturally occurs to one that the Tertiary subsidence and the intrusion of these igneous rocks are associated in some way ; but which is the cause and which the effect, the facts to be gathered at this locality do not indicate. The course of geologic events at this place as indicated by the geology of the region was as follows: time: Event. 1. At the close of the Carboniferous, the rocks of that age Close of the Gar- + were flexed, lifted, and subjected to very extensive subaerial boniferous. erosion. 9 ( The southeast margin of the eroded land sank beneath the : + ocean and the lower and Upper Cretaceous beds were depos- Early Cretaceous. l itea against and upon them. ( L 3 Close of the Cre- > taceous. The land was elevated and the Cretaceous beds exposed to a brief period of erosion. The igneous rocks were ejected through the Paleozoic shales 4. and sandstones and the clays and soft sandstones of the lower Early Tertiary. | (and upper?) Cretaceous, and the land sank beneath the seas i in which the Tertiary beds were laid down. 5. The Tertiary series was elevated and in the slow process of Bie passing through the beach condition, its soft beds were sub- OS CEU jected to extensive erosion and denudation. 6. § Quaternary. Quaternary events, which need not be specified here. Of about a dozen known occurrences of crystalline rocks in the state of Arkansas, the peridotite of Pike county offers the best evidence of the date of itsintrusion. All the other known exposures are north of the Cretaceous area and in a region in which metamorphism has been so general that every trace of the paleontologic evidence of the age of the rocks penetrated that may have existed has been entirely obliterated, and we are therefore unable to determine by any evidence thus far col- lected, the precise age of those beds, and are consequently un- able to determine the age of the eruptives. The syenites of Little Rock are not Archzean as they have so long been supposed, but are intrusions into Paleozoic rocks, probably of Lower Carboniferous age. They are overlain, how- 56» Branner and Brackett—Peridotite of Arkansas. ever, by Tertiary beds. The Magnet Cove crystallines are also in Paleozoic rocks, and are overlain here and there by Post: tertiary debris. PartiIl A Microscopic Study of the Peridotite of Pike County, Arkansas, by Richard N. Brackett. THE specimens of eruptive rock from the middle hill shown in the map, consists in the main, of a dark colored somewhat green, heavy rock having a porphyritic structure, and specific gravity of 2°728 to 2-651. Examined microscopically it is seen to be made up of black grains, some slightly yellow and having glistening surfaces, imbedded ina dark green to brownish-green groundmass. The material from the base of the northeastern hill, is a brown, much decomposed rock, with a more distinetly porphyritic structure due to the decomposition of the black to yellow grains, and of the groundmass to a decided brown, against which the yellow grains stand outsharply. The specitie gravity of this rock is 2° B17. Through it extends a vein of white barite about four inches in thickness. In contact with the barite vein are veins of serpentine formed by the decomposition of the rock. In immediate contact with the barite the serpentine vein is white, but shades through a light green into the brown rock. A microscopic study of thin sections prepared from speci- mens from the first exposure mentioned, reveals a rock of true porphyritic structure, consisting of crystals and grains of more or less decomposed, colorless olivine and some irregular patches of a yellow to brownish-yellow mica imbedded in a quite uni- form, fine-grained groundmass made up of colorless little lath- shaped crystals, yellow grains, black grains and a yellowish base (Nos. 84, 35 and 36).* The olivine er ystals and grains are decomposed in the usual well-known way, being cr wracked and chan ged to serpentine along the cracks. Few or none of the olivines are entirely un- changed, though there are many fresh cores and almost entire grains and cr ystals remaining. (No. 35). Where no olivine is left the outlines of the former olivine crystals are often well preserved. In such eases the olivines are entirely changed to serpentine, of both yellow and light green color and to carbon- ates, and hydroxide of iron, to which last the reddish stain of many is due (Nos. 34 and 36). Many of the decomposed oliv- ines contain also ‘ trichites,’ slender, black, hairlike bodies which occur singly and in bunches. These “trichites” are probably magnetite. *Numbers in parenthesis refer to numbers of specimens in the collections of the Geological Survey of Arkansas. Branner and Brackett—Peridotite of Arkansas. 57 The yellow mica is grown through with little colorless lath- shaped crystals like those in the groundmass. It has a weak pleo- chroism; O=orange or faintly reddish; E=yellow.* In some eases the patches of mica are of a darker color and have a stronger pleochroism: O=brown; E=light brown, almost yellow (Nos. 34 and 36). The colorless lath-shaped crystals that make up a large por- tion of the groundmass and penetrate the patches of mica, have an extinction angle as high as 45°, and many of them give lively polarization colors. From their association, appearance, optical behavior and close resemblance to similar erystals found in the groundmass of the Syracuse serpentine (to be referred to later), they are probably augite. They were so considered by Dr. Williams who has kindly examined a section of this rock. The yellow grains are scattered all through the groundmass, and are next in importance to the augites, and like them are an original constituent of the rock. They are highly refracting, and stand out well in the slide. In color they range from colorless through yellow to yellowish-brown. In form, some appear as irregular grains, others are diamond-shaped or square. They occur singly or grown together in groups. Very many have crystalline planes and few or none of them are quite isotropic. They resemble very closely the yellow grain described by Dr. Williams+ as occurring in the serpentine (peridotite) from Syracuse, New York, which he found by actual separation and analysis to be perofskite. Mr. J. S. Diller { described yellow grains in the peridotite from Elliott County, Kentucky, which they resemble, perhaps, more closely than they do those described by Dr. Williams. Mr. Diller at first took these to be anatase, but a subsequent separation and analysis showed them to be perofskite also. An unsuccessful attempt was made by the writer to separate the yellow grains by the method of Stelzner§ as recommended by Dr. Williams in his paper on the Syracuse serpentine. But the identity in appearance of the yellow grains in the Pike County rock with those in the Kentucky peridotite which Mr. Diller found to be perofskite after this attempted separation was made, coupled with the fact that by Gooch’s method | 0.89 per cent of TiO, was found in the rock, made it so probable that the mineral was perotskite, that no further attempt at separation was made. *(Slide No. 35). Determined by Dr. G. H. Williams, Johns Hopkins Univer- sity. To Dr. Williams thanks are also due for kindness in examining a section of this rock, and for a specimen of the Syracuse serpentine. + This Journal, xxxiv, August, 1887, pp. 140-142. t Bulletin of U. S. Geological Survey, No. 38, p. 18. § Neues Jahrbuch fiir Mineralogie, etc., Beitrage Bd. ii, p. 392. || American Chemical Journal, vol. vii, p. 283. 58 Branner and Brackett—Peridotite of Arkansas. The presence of perofskite here is interesting as being the third instance of its occurrence as a constituent of any Ameri- ean rock, the first instance being that reported by Dr. Wil- liams in the Syracuse serpentine, “the second that by Mr. J. S. Diller, in the peridotite from Elliott County, Keutucky. It is also interesting as occurring in the same type of rock as will be mentioned later. The black grains scattered in not inconsiderable quantity through the groundmass, are believed to. be magnetite. The yellow base mlooles as though it had been a class once and some of it is still isotropic, though most of it polarizes, fies considerable amount of it is still isotropic as was found in other sections (No. 36 and 42.) From its mineral composition and structure, then, this rock belongs to the family of perido- tites, and to the new type of picrite porphyry or “ Kimber- lite” of H. Carvill Lewis.t The rock differs somewhat from either of the other occur- rences. Unlike the Kentucky peridotite it contains no ensta- tite, its pyroxenic constituent being augite. It contains no ilmenite, and in only one section was any garnet found, a single, small, pink piece, quite isotropic. The perofskite, especially, occurs in great abundance in the Pike County rock and here is undoubtedly original, while in the Kentucky rock it is believed to be secondary, arising from the decomposition of the ilmenite, and the quantity is comparatively small. Finally the Kentucky peridotite contains much more fresh olivine than that from Pike County, and pyrope which is abundant in the former is rare in the latter. The Syracuse serpentine or peridotite, on the other hand, is much less fresh than the Pike County rock, and while it contains augite in the groundmass, the augites are much less abundant, as are also thes perofskites. This rock is in some respectsa new type. There is total absence of a rhombic pyroxene, which occurs as such in Mr. Diller’s rock, and is probably represented by decompo- sition products in the Syracuse serpentine. The brown rock, of which there is an exposure not far from the picrite por phyry just described, shows in thin sections a similar porphyritic structure. But here all the olivines are changed to serpentine, carbonates and hydroxide of iron. The outlines of the olivine and the structure of the rock are gener- ally well preserved, although no fresh olivine remains. A great many patches of mica, partially grown through with colorless little augite crystals are present, and_perotskite is abundant. The most striking characteristic of the rock is the almost total absence of auigite in the groundmass. This * Dr. Williams on No. 35. + Rosenbusch, Mik.-Phys., vol. ii, p. 519. T. M. Chatard— Urao. 59 absence of augite is rendered still more striking by the fact that in the Syracuse peridotite, which is no more decomposed than this rock, the augites in the groundmass are apparently as fresh as when they were first formed. The explanation of this probably lies in the fact that the patches of yellow base, some of which is quite isotropic, are much more abundant here than in the other rock described, and, perhaps, the augites did not have a chance to crystallize out, being deposited as a glass. There seems to be no doubt from its general appear- ance that this is a portion of the same original rock mass as that before described, and probably so situated with reference to it at the time of formation, that the now brown rock erystallized more rapidly than the other portion of the erup- tive mass, represented by the rock at the first exposure described. The dyke of blue earthy material, spoken of in Part L, has yellow grains scattered through it. The nature of the original rock, which this blue decomposed dyke represents, cannot be definitely determined. A thin slice shows a few fragments of brown mica, and sections composed entirely of serpentine, occurring for the most part in irregular grains, but occasionally showing the form of olivine, imbedded in a green to bluish-green groundmass, which appears to be partly serpentine and partly chlorite. The porphyritic grains are composed of white, yellow and greenish yellow serpentine. The arrangement of the serpentine, the olivine forms still preserved, indicate that all the porphyritic serpentinized sec- tions originally were olivine. It is quite probable that the rock consisted once of olivine with a small quantity of biotite im- bedded in a groundmass made up largely of glassy base con- sisting chiefly of olivine substance which has weathered to serpentine and chlorite. Art. VI.—On Urao; by THomas M. CHaAtarp.* In this Journal for August, 1888, p. 146, I gave the analyses of the waters of some iusto alkali lakes, among them, Owens Lake, Cal. The salts now to be described were obtained by the spontaneous evaporation of the water of the lake, and in connection with the results obtained from other localities, throw much light on the true character of the composition of the na- tive sodium carbonates. * Condensed from ‘‘ Natural Soda, its occurrence and Utilization,” a forthcoming bulletin of the U. 8. Geological Survey. Published by permission of the Director. 60 ° T. M. Chatard— Urao. The occurrence, in Venezuela, of the mineral urao has been described by Faxar* and by Boussingault.+ The latter gives the following analysis : Hypoth. Comp. Na,O.... 41-22 Na. CO i 46.96 CORB 39°00 NaliCO 2 37°24 [oS eam 2 Je 18°80 H.0 2208 14°80 Impurities 0°98 Impurities_ 0:98 100-00 100°00 By deducting the impurities from this analysis, Laurentt obtained as the formula of the pure salt, Na,CO,, NaHCO,+2H,0. The impurities in such salts are insoluble matter, with chloride and sulphate of sodium, all of which can be deducted when we wish to calculate the formula since they are, under the circum- stances, anhydrous and merely diminish the percentage of urao in the material. If we deduct the impurities from this analysis and recalculate the residue to 100 per cent, and likewise calculate the theoretical percentages for the above formula, we shall have : Found. Theoret. Hypoth. Comp. Theoret. Na,O Ba ARIES} 41°15 Na, CO, fae, db 46°90 Coy ee ees 39°38 38°94 NaHCO, Sah B77 AG Seiealyi LA@ Stet US: 99g 9:9 ae O) eae 14°95 15°98 100°:00 100:00 100°00 100:00 If we take the theoretical proportion between the Na,CO, andthe NaHCO, we have Na,CO,: Na,HCO,:: 106 :84::47-44 : 38751 while the amount of NaHCO, found in 37°61, a difference of only 0-11 per cent. Hence Boussingault’s urao is an almost theoretically pure salt, showing only a small loss of water and a trifling increase of NaHCo,. The existence of a native sesquicarbonate of sodium, Na,OO,, 2NaHCO,+3H,O, to which the mineral name trona has been given, rests on an analysis by Klaproth,§ and under this head the numerous analyses of natural sodas to be found scattered through the literature of the subject have been referred. A careful revision aad recalculation of these analyses, in the man- ner described above, show that none of them, excepting those of Popp,| agree, even reasonably closely, with this formula, * Faxar, Ann. de Chimie, II, ii, 432. + Boussingault, ibid., II, xxix, 110. ¢ Laurent, Ann. de Chimie, III, xxxvi, 348. § Klaproth, Beitrage, iii, p. 83, 1802. || Popp, Ann. der Chem. u Pharm., 155, p. 348. T. M. Chatard— Urao. 61 but that on the contrary, the salts were uraos with a widely varying excess of one or the other of the two carbonates. A repetition of Winkler’s* method for the artificial production of sodium sesquicarbonate gave additional proof, for the salt ob- tained was physically and chemically a urao having an excess of NaHCO, as would be expected from the conditions of this formation. Hence the conclusion that there is no such salt, either natural or artificial, as sodium sesquicarbonate, but that the true salt is a union of one molecule of Na,CO, with one of NaHCoO,, although the presence of an excess of NaHCO, may occasionally give results approaching the composition of a sesquicarbonate. Many analyses, notably those of Wallace,t who suspected the non-existence of sesquicarbonate, show uraos containing an excess of Na,CO, while de Mondesirt was the first to publish a method for the artificial production of the pure salt to which, on account of the relation of 3NO,O to 4CO,, he gives the name “carbonate quatre-tiers” or “four thirds cear- bonate.” It might be called the “tetra-trita” or “ tetrita- carbonate.” The five salts now to be described, were obtained by spon- taneous solar evaporation of natural water and hence are “ min- erals.” Nos. 1 and 2 are from the same specimen and were formed in an artificial ground vat. When the water of Owens Lake is allowed to evaporate, the first crop obtained is granular crystalline and retains much mother liquor. The mother liquor is therefore drawn off and this first crop, as far as practicable, redissolved in lake water, thus forming a new solution which de- posits a sheet of crystals much larger and purer than the first product. The specimen of this sheet taken for analysis was about two inches thick ; the upper portion was well crystallized and translucent (No. 1); the intermediate part showed an inter- lamination of thin, translucent, crystallized sheets and of fine- grained crystalline, white material (No. 2), the undissolved por- tion of the first product; the bottom part of the specimen was a layer similar to the upper portion but thinner, the crystals being much smaller. No. 1 presented a radiated columnar structure, the crystals being so grown together that the termina- tions alone were visible and these so combined that each com- bination had a curved ridge-like termination or cock’s-comb form. The specific gravity of this material was 2:1473 taken in benzol at 21°7° C. No. 3 or “Twig” was formed on a branching grass-root which chanced to be suspended in the water of a small lagune on the east side of the lake. It has the form of a stout twig or of a * Winkler, Buchner’s Repert. f. Pharm., xlviii, p. 215, + Wallace, Chem. News, xxvii, p. 203. } De Mondesir, Comptes Rendus, civ, p. 1505, May 31, 1887. 62 T. M. Chatard— Urao. branching coral, each of the branches forming a cylinder, a see- tion of which shows the radiated structure, while the surface of the cylinder is rough, the curved edges of the crystal aggregates giving a lenticular appearance. The color is brownish and one side of the specimen shows crystals of NaCl and much sand as the evaporation of the water finally left it lyimg on the mud of the bottom. ; No. 4 or “ Lagune” is from another small lagune near by, and consists of a thin sheet, the surfaces of which are rough like the preceding specimen. Color pink, due to organic matter. No. 5 or “ Beach vat” was formed in a vat dug in the beach and allowed to fill by seepage from the surrounding soil. This seepage water differs somewhat in composition from the water of the lake. No. 1. No. 2. No. 3. No. 4. No. 5. Twig. Lagune. Beach yat. Insol]. inorg. "02 "22 2°92 40 4°10 “ organic eons aan 14 12 a SiO eee ee 10 ‘05 09 04 CaQeie ss. eae fe es ieee 06 ae Mio Ore ane eres 5 es saat 02 ee RON a2 Seat oe une saa tr. ee: Nan Omer os 3.40°995 41°26 40°22 40°08 39°36 CVE caes z 6193 1°57 2°73 zal 1°83 SOU e702 79 ‘76 63 "84 COV Tes 38138 370059) 85:24 37.50) as oO ELKO pa pees 8 20°07 19°62 1831 1994 1858 100711 100756 100°37 99°05 100°12 O= Chee: 04 “35 ‘61 05 4] 10007 =100°21 99°76 99:00 99°71 Calculating the hypothetical composition, deducting the im- purities and recalculating to 100 per cent we have: No. 1. No. 2. No. 3. No. 4. No. 5. Na ©O.2--) 46°57" 47-20. 46776 440035) pedanas NaHCO,.- 37.08 936:22, 137-04) wa2;suiusGies EE Oe ae: 16°40! 6:58 | | 16:20, 2 17 1oe aller 100700 100°00 100°00 100°00 100:00 If we compare these new percentages with the theoretical figures for urao, previously given, we shall find the following dif- ferences. Theoret. No. 1. “No.2: No: 357) No: 4) Nota: Na,Co,---- 46°90 —°33 +4°30 —'14 +43°45 —-25 NaHCO, - 8717 — 14 —95 -—'138 —464 —-34 EOE S hae s 15°93 +47 4°65 +27 +4119 +°59 T. M. Chatard— Urao. 63 These small differences show that each of the samples is urao. In each case there is a varying amount of other salts and impu- rities to be deducted, but when this is done the residue, in four out of the five samples, shows a very close agreement with the formula of the mineral. In the case of No. 4 or the “ Lagune” the differences are quite large, but as the local conditions attend- ing the production of each specimen are well known, the expla- nation is simple. Unlike the others which are products of un- disturbed crystallization, this one is apparently the result of an interchanging concentration and dilution of the mother liquor in which it was formed. As the water in such a shallow basin evaporates the tendency is to leave a crust of very pure urao, at the edge of the basin, the deposit towards the center becoming more and more impure as the concentrating liquid deposits its chloride and sulphate and becomes, as experiments show, a comparatively pure solution of sodium mono-carbonate. If then the basin be refilled by seepage, as would be the case when the lake rises in the spring, the solution would contain a larger proportion of the neutral carbonate and, on reconcentra- tion, would leave on its edges a urao containing an excess of hydrated monocarbonate. If we calculate the excess of mono- carbonate and water present, we shall tind that the two combine to form Na,CO,+2H,0O and that the sample represents 84°71% urao, 12:°06% Na,CO,, 2H,O, 02% H,O and 2-214 impurities. Artificial Urao. A series of experiments was undertaken, in order to deter- mine the conditions under whieh urao is formed and also to find out if, by spontaneous evaporation, under known condi- tions the sesquicarbonate or any other combination of mono- and bicarbonate, other than urao, might be formed. For this investigation a number of solutions was prepared, each of which contained Na,CO,, NaHCO, and NaCl, the amount of each salt employed having a certain definite relation to its molecular weight. NaCl was added because its presence appears to exer- cise a favorable influence on the crystallization of the mixed carbonates. A full account of these experiments and results will be found in the Bulletin from which this paper is con- densed ; for the present it is sufficient to say that in no case, no matter what the relative proportions of the salts might be, was any other mixed carbonate but urao obtained. If the NaHCO, was present in excess a portion crystallized out first, as such, ‘but this was invariably followed by erystallizations of urao. On the other hand if the Na,CO, was in sufficient excess, the ura9 first obtained was contaminated with the former salt. The following examples will show this. The solutions were made up as follows: 64 T. M. Chatard— Urao. No. 1.) No: 25 “Nov No: 65) Nos iaaeNomo: NaHCO, erms..- 10°5) 21:0 10°!) 910°5\ | 42s0N aaa Na,CO, eo LES 330 53°0 53°0 53°00 §=6538'°0) =—33°50 NaCl cL 29°25" 29°25 | 14°69) 95 8"5! | SSramee wa The first pee obtained from the solutions by spontaneous evaporation had the following compositions : No. i, Ist. No. 2, 1st. No. 5, Ist. No. 6, Ist. No. 7, 1st. No. 9, 2d. Acicular. Scales. Acicular. Acicular. Seales. Acicular matted. HiOests 19°58 WAL: 19°54 19°42 11°63 18°9] CO, Beng Fie ei “MOO site Bese 51:52 «= 8646 INE OES ADO eXaesy48 ) VARIA = - Sites 36°49 ©39°22 NaCl: 1-46 51 1-79) 2-88) we unclenamnseaS 99°84 100°52 100716 99°91 99°64 100°27 Hypothetical Composition. JeO) ay TS 1-25. © 15°96. “15355 92 15°41 Na,CO,. .43°69 42 49°00 = 45-29 “64 46°60 NaHCO, 39°32 98°34 33°48 36:19 98°08 32°68 Na CIEN: 1°46 soi 172 2°88 undet. 5°58 99°84 100°52 100°16 99°91 99°64 100°27 Urao. NaHCO; Na.CO3,H.2.0 H.O NaCl No. 1] corresponds to 93°15+ 470+ ..-. ‘538+ 1°46 No. 2 * 894-5 OS:Ol >) La eee lees ‘51 No. 5 ts © 90:08--) © 2 l-E> 7°89 47 No. 6 c “9656-4 “8045 ) ae | 17 orgs No. 7 re «1374 9757+ ..-- 70+ mndet. No. 9 i So 8 OD) eee 6227 50+ 5°58 A solution made up in the proportions of No. 6 would seem to be best.for the production of this salt as the crystallizations were much finer than in any of the others. If the proportion of NaHCO, is increased, the excess separates before the urao is formed, while if it is reduced the urao contains monohydrated carbonate. The presence of NaCl is not absolutely necessary, for experiment has shown that a very good erystallization of urao can be obtained without its aid, and even a solution of chemically pure Na,CO,, if exposed to the air for some time so that it can absorb OO,, will yield crystals of the double salt. It is therefore somewhat remarkable that this salt which seems to be the natural form of sodium carbonate, should receive no notice in the most extensive treatises on the sodium salts or, if mentioned, be confounded with another which, so far as my own observations extend, does not exist at all. E. F. Ayres—Notes on the Crystallization of Trona. 65 Art. VII.—Wotes on the Crystallization of Trona ( Urao) ; by Epwarp F. AYREs. AN examination has been made by the writer of a series of erystals of trona, in part natural crystals from Borax Lake, San Bernardino Co., California, and in part artificial crystals, furnished through the kindness of Dr. Thomas M. Chatard. The natural crystals are of considerable size, up to 15"™™ in length, but they were rough and so covered with saline incrus- tations that they afforded no good measurements. In habit they were flat and tabular with the basal plane largely devel- oped and some indistinct orthodomes all deeply striated; they were terminated by the usual pyramidal planes (0). The artificial crystals gave much better opportunity for accu- rate crystallographic work. These are slender acicular crystals very much elongated in the direction of the orthodiagonal axis. They average from 8 to 15™™ in length and about 1™™ in diameter; they are usually grouped in little radiating clusters. The different samples received from Dr. Chatard vary among themselves chiefly in size; some of them being excessively slender. Those which were subjected to measurement were from one of the samples mentioned by Dr. Chatard. The sym- metry of these crystals may be viewed as almost orthorhombic, the angles ae, ec, and ao’’, co respectively varying but little from each other. This is shown in fig. 2, a projection on the clinopinacoid plane. - The crystallization of trona was first described by Haidinger* in 1825, and recently Zepharovicht has given a new determina- tion of the form with a number of new planes; he gives as the ‘composition Na,C,O,, + 5H,0O. The position here adopted is that of Zepharovich. The planes observed are: a(100, 7-i), c(001, O), e101, —1-2), s(302, $2), p(111, —1), o(111, 1), r(211, —2-2). The two planes p (111) and rv (211) are new; p (111) is quite brilliant though small, and 7 (211) gives angles close enough for identification. The habit of the more complex crystals is shown in fig. 1. There is very perfect cleavage parallel to the * Pogo. Ann., v, 367, 1825. { Zeitschrift f. Kryst., xiii, 135, 1887. Am. Jour. Sc1.—TuHirpD SERIES, VoL. XXXVIII, No. 223.—Juny, 1889. 5 66 J. Croll— Evidence of former Glacial Periods. orthopinacoid, which affords surfaces suitable for measurement, but the other planes in the orthodome zone are striated parallel to the macrodiagonal axis, and the angles they yield are less satisfactory. The ery stals when newly prepared are very bright and transparent, but soon lose their luster on exposure to the air. For fundamental angles the following were accepted : 007% 11 ~ W472 30% ‘co 001 A TI —762075 ao 00) 11 oan The axial ratio obtained is as follows, that of Zepharovich being added for sake of comparison : Q all bo (o-) == 2842612 We e2i94 94" 1G ==N6e se GS We > 8459: 1: 2°9696, B=T7T° 23” Zeph. The following table gives a comparison between caleulated and measured angles : Calculated. Measured. Limits. LA Wa AT? 30’ eA 307 AT? 194 ATS 56: OOlAIN= 116. »-10; 116) lO UE Ai TSI NO Zi ove wlan OW, lta aS Ol 75 to tbe BxaE OO) 4 aa = 67 14 13 Gs 65 53 -to 68 23 OOS NO) Bt. Dis}, WS 38 approx. 0014101 = SOMES Bx) 3a) 40 39to40 387 TA ee 37 38 17 Siiae3e 36) §35)to36) 397 ooOl~AlI= 6825 1829 52) 92 6nnoS 8 NO ORG2 By LIE ts} 52) 44 001 4302 = 68 10 14 67 approx. 0014100 = UG SW OLA One 70 46 43 OOP V10 = 70 6 44 NOOO 1e== Bihn PAPAS} Art. VIUL—On prevailing misconceptions regarding the Evidence which we ought to expect of former Ce Periods ;* by JAMES CROLL, LL.D., ¥.R.S. WiItTHIN the whole range of geological science there is per- haps not a point on which a greater amount of misapprehen- sion prevails than in regard to the evidence which we ought to expect of former Glacial periods. The imperfection of geo- logical records is far greater than is generally believed: so great, indeed, that the mere absence of direct geological evidence can “hardly be regarded as sufficient proof that the conclusions derived from astronomical and physical considera- tions regarding former ice-periods are improbable. Nor is this * From the Quarterly Journal of the Geological Society of London for May 1889, by request of the Author. J. Crolli— Evidence of former Glacial Periods. 67 all. Not only are the geological records of ancient glacial con- ditions imperfect, but this imperfection follows as a natural consequence from the principles of geology itself. ‘There are not merely so many blanks or gaps in the records, but a reason exists in the very nature of geological evidence why such breaks in the record might naturally be expected to occur. The evidence of Glaciation is to be found chiefly on land- surfaces.—lt is on a land-surface that the principal traces of the action of ice during a glacial epoch are left, for it is there that the stones are chiefly striated, the rocks ground down, and the bowlder clay formed. But where are all our ancient land- surfaces? They are not to be found. The total thickness of the stratified rocks of Great Britain is, according to Professor Ramsay, nearly fourteen miles. But from the top to the bot- tom of this enormous pile of deposits there is hardly a single land-surface to be detected. Patches of real old land-surfaces of a local character may indeed be found, as, for example, the dirt-beds of Portland; but, with the exception of coal-seams, every general formation has been accumulated under water, and none but the under-clays ever existed as a land-surface. And it is here, in a general formation, that the geologist has to collect all his information regarding the existence of former glacial epochs. The entire stratified rocks of the globe, with the exception of the coal-beds and under-clays (in neither of which would one expect to find traces of ice-action), consist almost wholly of a serzes of old sea-bottoms, with here and there an occasional fresh-water deposit. Bearing this in mind, what is the sort of evidence which we can now hope to find in these old sea-bottoms of the existence of former ice- periods # All geologists of course admit that the stratified rocks are not old land-surfaces, but a series of old sea-bottoms formed out of the accumulated material derived from the degradation of primeval land-surfaces. And it is true that all land-surfaces once existed as sea-bottoms; but the stratified rocks consist of a series of old sea-bottoms which never were land-surfaces. Many of them no doubt have been repeatedly above the sea- level, and may once have possessed land-surfaces; but these, with the exception of the under-clays of the various coal measures, the dirt-beds of Portland, and one or two more patches, have all been denuded away. The important bearing which this consideration has on the nature of the evidence which we can now expect to find of the existence of former glacial epochs has certainly been very much overlooked. If we examine the matter fully we shall be led to conclude that the transformation of a land-surface into a sea-bottom will probably completely obliterate every trace of glaciation 68 J. Croll— Evidence of former Glacial Periods. which that land-surface may once have presented. We cannot, for example, expect to meet with polished and striated stones belonging to a former land glaciation; for such stones are not earried down bodily and unchanged by our rivers and deposited in the sea. They become broken up by subaerial agencies into grayel, sand, and clay, and in this condition are transported seawards, Even if we supposed it possible that the stones and bowlders derived from a mass of till could be carried down to sea by river action, still these stones would certainly be deprived of all their ice-markings, and become water-worn and rounded on the way. Professor James Geikie states that the ereat accumulations of gravel which occur so abundantly in the low grounds of Switzerland, and which are, undoubtedly, mer ely the re-arranged materials originally brought doww from the Alps as till and as moraines by the glaciers during the Glacial period, rarely or never yield a single scratched or glaciated stone. The action of the rivers escaping from the melting ice has succeeded in obliterating all trace of strie. It is the same, he says, with the heaps of gravel and sand in the lower grounds of Sweden and Norway, Scotland and Ireland. These deposits are evidently in the first place merely the materials carried down by the swollen rivers that issued from the gradually melting ice-fields and glaciers. The stones of the gravel derived from the demolition of moraines and till, have lost all their strize and become in most cases well rounded and water-worn. Further, we cannot expect to find bowlder clay among the stratified rocks, for bowlder clay is not carried down as such and deposited in the sea, but under the influence of the denuding agents becomes broken up into soft mud, clay, sand, and gravel, as it is gradually peeled off the land and swept seawards. Patches of bowlder clay may have been now and again forced into the sea by ice and eventually become covered up; but such cases are wholly exceptional, and their absence in any formation cannot fairly be adduced as a proof that that formation does not belong to a glacial period. It may, however, be replied that there is one kind of evi- dence of former glacial periods which we ought to expect in the stratified rocks, viz: the presence of large erratic blocks embedded in~ strata which, from their constitution, have evidently been formed in still water. But even allowing this to be the case we cannot regard the absence of such blocks as proof that no glacial period occurred during the time of the formation of the strata; for their mere absence may be the indication either of a period of extreme glaciation, or a period absolutely free from ice. This absence is a result which would as truly follow from the former condition of things as from the latter. Glaciers carry erratic blocks on their surfaces, J. Crolli— Evidence of former Glacial Periods. 69 but such blocks are seldom, if ever, on the surface of an ice- sheet. The reason is obvious. When a country is completely buried under ice there is no source from which the ice can obtain erratics on its surface. The stones which lie under the ice, before they can reach the sea, are ground down to powdevr. Large erratic blocks have never been found, for example, on the ice-sheet of Greenland. No one, of course, has as yet had an opportunity of examining the surface of the Antarctic ice, but judging from the character of the icebergs derived from it, we are almost certain that it contains no bowlders. Were the seas surrounding these continents elevated into dry land, a geologist judging from the comparative absence of bowlders in the sedimentary deposits which have been forming for the past thousands of years, would be apt to conclude that these con- tinents had never been covered by ice. In fact, a conclusion of this kind has been arrived at by Professor Nordenskjéld, who maintains, because he has never seen in the strata of Greenland or Spitzbergen a bowlder larger than a child’s head, that down to the termination of the Miocene period, no glacial condition of things existed in these regions: a conclusion most certainly utterly erroneous. Now both of these lands are at present in a state of glaciation; and were it not for the enor- mous quantity of heat which is constantly carried northward from the equatorial regions by the Gulf Stream, not only Greenland and Spitzbergen, but the whole of the Arctic regions would be far more completely under ice than they are. A glacial state of things is the normal condition of polar regions; and if at any time, as during the Tertiary age, the Arctic regions were free from snow and ice, it could only be in consequence of some peculiar distribution of land and water and other exceptional conditions. That this peculiar combina- tion of circumstances should have existed during the whole of that immense lapse of time between the Silurian and the close of the Tertiary period is certainly improbable in the highest degree. In short, that Greenland during the whole of that time should have been free from snow and ice is as improbable, although perhaps not so physically impossible, as that the interior of that continent should at the present day be free from ice and covered with luxuriant vegetation. In fact, it is the severity of glacial conditions in these re- gions during glacial periods that has rendered the strata to which Prof. Nordenskjéld refers so comparatively free from erratic blocks. Had these regions been occupied by glaciers reaching to the sea, instead of being covered by a sheet of ice, bowlders in the strata would no doubt have been far more common. As evidence of former glacial periods we may, however, ex- 70 J. Croll—Evidence of former Glacial Periods. pect to find in temperate regions erratic blocks, imbedded here and there in the stratified rocks, which may have been trans- ported by icebergs and dr opped into the sea. But unless the glaciers of such epochs reached the sea, we could not possibly possess even this evidence. This sort of evidence, when found in low latitudes, ought to be received as evidence of the exist- ence of former glacial epochs; and, no doubt, would have been so received had it not been for the erroneous idea that, if these blocks had been transported by ice, there ought in ad. dition to have been found striated stones, bowlder clay, and other indications of the agency of land-ice. It is, of course, by no means the case that all erraties are transported by masses of ice broken from the terminal front of glaciers. The “ice foot,’ formed by the freezing of the sea along the coasts of the higher latitudes, carries seawards quantities of blocks and débris. Again, stones and bowlders are frequently frozen into river ice, and when the ice breaks up in spring are swept out to sea, and may be carried some little distance before they are dropped. But both these cases ean occur only in regions where the winters are excesswe ; nor is it at all likely that such ice-rafts will succeed in making a long voyage. If, therefore, the erratics occasionally met with in certain old geological formations in low latitudes were really transported from the land by an ice-foot or a raft of river-ice, we should be forced to conclude that very severe climatic conditions must have obtained in such latitudes at the time the erratics were dispersed. Why we now have, comparatively speaking, so little direct evidence of the existence of former glacial periods will be more for cibly impressed upon the mind if we reflect on how difficult it would be, in a million or so of years hence, to find any trace of what we now eall the glacial epoch. The ‘striated stones would by that time be all, or nearly all, disintegrated, and the till washed away and deposited in the bottom of the sea as stratified sands and clays. And when these became consoli- dated into rock and were raised into dry land, the only evi- dence that we should probably then have that there ever had been a glacial epoch would be the presence of an occasional large block of the older rocks found imbedded in the upraised formation. We could only infer that there had been ice at work from the fact that by no other known agency could we conceive such a block to have been transported and dropped in a still sea. Few geologists probably believe that during the Middle Eocene and the Upper Miocene periods our country passed through a condition of glaciation as severe as it has done dur- ing the Post-pliocene period; yet when we examine the sub- J. Croll— Evidence of former Glacial Periods. (al ject carefully, we find that there is actually no just ground to conclude that it has not. For, in all probability, throughout the strata to be eventually formed out of the destruction of the now existing land-surfaces, evidence of ice-action will be as scarce as in Eocene or Miocene strata. Did the stratified rocks forming the earth’s crust consist of a series of old land-surfaces instead (as they actually do) of a se- ries of old sea-bottoms, then traces of many glacial periods might be probably detected. Nearly all the evidence which we have regarding the Glacial period has been derived from what we find on the now existing land-surfaces of the globe. But probably not a vestige of this will exist in the stratified beds of future ages, formed out of the destruction of the pres- ent land-surfaces. Even the very arctic shell-beds themselves, which have afforded to the geologist such clear proofs of a frozen sea during the Glacial period, will not be found in those stratified rocks; for they must suffer destruction along with everything else which now exists above the sea-level. There is probably not a single relic of the Glacial period which has ever been seen by the eye of man that will be treasured up in the stratified rocks of future ages. Nothing that does not lie buried in the deeper recesses of the ocean will escape com- plete disintegration and appear imbedded in those formations. It is only those objects which lie in our existing sea-bottoms that will remain as monuments of the Glacial period of the Post-tertiary era. And, moreover, it will only be those portions of the sea-bottoms that may happen to -be upraised into dry land that will be available to the geologist of future ages. The point is this: /s 7 probable that the geologist of the future will find in the rocks formed out of the now exist- ing sea-bottoms more evidence of a glacial epoch during Post- tertiary times than we now do of one during, say, the Miocene, the Eocene or the Permian period? Unless this can be proved to be the case, we have no ground whatever to con- clude that the cold periods of the Miocene, Eocene and Per- mian periods were not as severe as that of the Glacial period. This is evident, for the only relics which now remain of the glacial epochs of those periods are simply what happened to be protected in the then existing sea-bottoms. Every vestige that lay on the land would in all probability be destroyed by ee agency and carried into the sea in a sedimentary orm. The question of the existence of former glacial periods is one on which paleontology can afford but little really reliable information. One of the main characteristics of a glacial pe- riod is the scarcity or comparative absence of plant and ani- mal life. He certainly would bea bold geologist who would 72 G. F. Kunz—Mineralogical Notes. affirm, in relation to a given epoch, that because he could not find the remains of plant and animal life which he considered could have existed under glacial conditions, no glacial econdi- tions existed during that epoch. And the more so seeing how difficult it is to determine with certainty, more especially in relation to remote periods, how much cold a plant or an ani- mal might be able to endure. Besides all this, supposing the organic remains of former glacial epochs were found in abundance, these remains would probably mislead most geologists. For if the theory of the glacial epoch, advocated in “Climate and Time” be correct, viz: that those epochs consisted of alternate cold and warm periods, it is evident that the greater part, or nearly all of those remains would belong to the warm or interglacial peri- ods. A geologist who did not believe in interglacial periods, judging from the character of those remains, would naturally come to the conclusion that the epochs in question were warm and equable, not glacial. His disbelief in interglacial periods would thus induce him to give a wrong interpretation of the facts. Assuming that a glacial epoch occurred at every time that the earth’s orbit attained a very high state of eccentricity, it is quite apparent, when we reflect on the imperfection of geolog- ical records on the matter, that we have in reality about all the evidence which we could possibly expect of the existence of such epochs. Art. [X.—Mineralogical Notes, on Fluorite, Opal, Amber and Diamond ; by GEORGE F. Kunz. Fluorite.—About four years ago, a small vein of fluorite in Archzean limestone was discovered in the town of Macomb, St. Lawrence Co., New York. It was worked from time ‘to time until last summer, when the vein suddenly widened, breaking through into a cavity or cave. This cave is 22 feet north and south, and 18 feet east and west, and is 8 feet below the surface. It dips from the south to the north, and is about 8 feet lower than at the mouth or entrance. It is about 5 feet between the walls. A pool of water in the northeast corner, about two feet in depth, often rises ten or twelve inches dur- ing the day. The top, bottom, and sides were lined with a magnificent sheet of crystals, varying from one to six inches in diameter, each in turn forming part of larger composite crys- tals. Between the floor and the walls was a layer of partly de- composed calcite, which was readily removed, so that groups G. F. Kunz—Mineralogical Notes. 73 of crystals, weighing from ten to several hundred pounds each, and one of them measuring 2X3 feet, were easily detached. The cavity contained at least fifteen tons of fluorite. The nabit of the erystals is, in nearly every instance, that of the simple cube, but the faces of the octahedron, slightly developed, are often present. Almost all the crystals have on the surface in small botryoidal elevations, an even coating of brown hydro- dolomite, which is readily removed with diluted hydrochloric acid. The crystals are all well colored, but the surfaces are dull. The fluorite is of a uniform light sea-green, except where it is attached to the gangue, or at the junction of the erystals ; here there are small spots, from one to two inches in diameter, of a rich emerald-green. Attached to the fluorite are small masses of lithomarge, and imbedded in these, very perfect tetrahedral crystals of chalcopyrite. With the fluorite are found small bunches of pyrite crystals, which are nearly al- ways altered to limonite. Galenite has not been observed, although this locality is only one and a half miles from the well-known Macomb Lead Mines. Several years ago, a large quantity of rhombohedral crystals of calcite were obtained here; one now in the State Cabinet of Albany weighs 120 pounds and a number were of the size of a man’s head, in form they were simple rhombohedrons and twinned. This find is strikingly like that of the famous Muscalonge Lake lo- calities of forty years ago, except that the crystals are of a finer color and in larger groups. The occurrence of a second deposit in this country leads to the inference that fluorite may exist incommercial quantity, for the arts. Amber.—For the last fifteen or twenty years, travelers have occasionally brought specimens of a very remarkable amber from some locality in Southern Mexico. The only informa: tion gained concerning it is that it is brought to the coast by natives, who say that it occurs in the interior so plentifully that it is used by them for making fires. The color of this amber is a rich golden yellow, and when viewed in different position it exhibits a remarkable fluorescence, similar to that of uraniné, which it also resembles in color. A specimen now in the possession of M. T. Lynde measures 4x32 inches, is perfectly transparent, and is even more beautiful than the fa- mous so-called opalescent or green amber found in Catania, Sicily. This material would be extremely valuable for use in the arts. It is believed that an expedition has started for the locality where it is found in the interior. Opal.—A specimen of fire opal 1414 inches in size, evidently a water-worn fragment, was found near John Davis River, in Crook County, Oregon. It is transparent, grayish- white in color, with red, green, and yellow flames. The play 74 G. fF. Kunz—Mineralogical Notes. of colors equals in beauty that of any Mexican material, and it is the first opal found in the United States that exhibits color. Undoubtedly, better material of the kind exists where this was found. LTramond.—During the summer of 1888 a small diamond was said to have been found by Mr. C. O. Helm, on the farm of Henry Burris, about three hundred yards from Cabin Fork Creek, Russell County, near Adair County, Kentucky. While walking through an old field, on the top of a hill, Mr. Helm observed in the gravel, this small, bright stone, which on in- vestigation proved to be a diamond, an elongated hexoctahe- dron, with curved faces, lustrous, but slightly off-color, weigh- ing 7/16 carats. The rock in the vicinity is said to be com- posed of granite dykes, slates, and some floating rocks, such as quartz, feldspar, magnetic iron ore, flint, garnet, etc., mingled in clayey hills. SCIENTIFIC INTELLIGENCH. I. CHEMISTRY AND PHYSICS. 1. On the action of Hydrogen peroxide.on Chromic acid.— BreRTHELOT has investigated the reaction which takes place when hydrogen peroxide is mixed with chromic acid or a chromate, and finds that if no excess of acid is present a given quan- tity of chromate can decompose an unlimited quantity of per- oxide, and this without suffering itself any apparent change. This result he accounts for upon the supposition that an unstable inter- mediate product is continually formed and decomposed. When solutions of the peroxide and potassium dichromate are mixed together, and as soon as the mixture has become dark brown in color, ammonia is added, a brown precipitate falls, which contains hydrogen peroxide, chromic acid and chromic oxide. It is very unstable, evolves oxygen even when washed with water, and gives a yellow filtrate containing chromate. The small residue finally left undissolved, contains the same constituents as the original precipitate but in quite different proportions.—C. f., evill, 24,157,477; Ber. Berl. Chem. Ges., xxiii, Ref. 217, May, 1889. Gaka Bs 2. On the Atomic Mass of Chromium.—The atomic mass of chromium has been determined by Rawson by means of am- monium dichromate, using two methods. The first consisted in igniting this salt, measuring the nitrogen evolved and weighing the chromic oxide remaining. The second depended upon the reduction of the dichromate with alcohol and hydrogen chloride, and the determination of the chromic oxide precipitated by am- monia. The first method, though simple in theory, did not prove Chemistry and Physics. 75 satisfactory in practice. The dichromate burned like tinder, the nitrogen coming off with such rapidity as to carry away some of the oxide and perhaps even some of the dichromate. Moreover, the gas set free does not seem to be pure nitrogen, but has a brownish color with a nitrous smell and an acid reaction. The second method resulted satisfactorily and gave for the ratio of the atomic mass of chromium to that of hydrogen in six experi- ments 52°130, 52°010, 52:020, 52°129, 52°016, 52°059 : the general mean being 52:061.—/. Chem. Soc., lv, 213, April, 1889. G. F. B. 3. On the new Element Gnomium.—Hueo MUuuer exhibited at the Conversazione of the Royal Society on May 8th, some com- pounds of the new element gnomium discovered by Kriiss and Schmidt of Munich as associated with the metals nickel and cobalt. Among the preparations shown were gnomium oxide, gnomium chloride (in aqueous solution), nickel from which the gnomium, which had always accompanied it hitherto, had been removed ; and nickel oxide also free from gnomium.— Nature, x], 67, May, 1889. G. F. B. 4. Concentration of Electric Radiation by lenses.—“ Prof. O. J. Lopes and James L. Howarp have constructed two large cylin- drical lenses of plano-hyperbolic section of mineral pitch cast in zinc moulds, the plane faces being nearly a meter square, the thickness at vertex 21 centimeters, and each lens weighed about 3 cwt. The eccentricity of the hyperbola was made 1°7 to ap- proximate to the index of refraction of the substance. The lenses were mounted about six feet apart with their plane faces parallel and toward each other on a table and an oscillator was placed about the principal focal line of one of them at a distance of 51 centimeters from the vertex. The field was explored by a linear receiver made out of two pieces of copper wire mounted in line on a piece of wood, and the air gap between their inner ends was adjustable by a screw. When the oscillator worked satis- factorily, the receiver would respond to about 120 centimeters, and with the lenses the distance was 450. ‘The receiver re- sponded ‘anywhere between the lenses and within the wedge between the second lense and its focal line, the boundaries being clearly defined, but no special concentration was noticed about the focus. Interference experiments were carried out by placing a sheet of metal against the flat face of the second lens, and de- termining the position of minimum intensity between the lenses. The distance between these points was 50°5 centimeters, corres- ponding with a wave-length of 101 centimeters, whereas the calculated wave-length of the oscillator was 10C centimeters. In a discussion upon the results of this experiment Prof. Fitzgerald said that he had made experiments on electrical radiations analo- gous to Newton’s rings, and had successfully observed the central dark spot and the first dark band.”— Physical Soc., London, May 11, 1889. Sade 5. Wave-length of the principal line in the Spectrum of the Aurora.—Hueeins details a careful determination of the position 76 Scientific Intelligence. of this line and finds its wave-length to be 5571+ 0°5. Vogel gives for the same line 5571°3 + 0°92. Gyllenskidld gives a value 5570°0 + 0°88. Krafft however found 5595 and 5586. Hug- gins points out that Lockyer’s recent statement “that the char- acteristic line of the aurora is the remnant of the brightest manganese fluting at 558,” is clearly inadmissible considering the evidence we have of the position of this line.—Wature, May 16, 1889. Joule 6. Quartz as an insulator._-At a Royal Society Conversazione, Mr. C. V. Boys exhibited an “experiment showing the insula- tion power of quartz. A pair of gold leaves are supported by a short rod of quartz which has been melted and drawn out about three quarters of an inch. The atmosphere is kept moist by a dish of water. Under these circumstances a glass insulating stem allows all the charge to escape in a second or two. With the quartz but little change is observed in four or five hours. The quartz may be dipped in water and put back in its place with the water upon it. It insulates apparently as well as before.”—Wa- ture, May 16, 1889. See IU 7. Light and Magnetism.—Mr. SHELFORD BIpWELL has made the following experiment. One end of an iron bar which had been magnetized and demagnetized, was placed near a magnet- ometer needle. On directing a beam of light on the bar an immediate deflection of the needle resulted, and on cutting off the light the needle promptly returned to near its initial position. The direction of magnetization induced by the light is the same as the previous maguetization, and the bar seems to be in an un- stable magnetic state. That the effect is due to light and not to heat, the author thinks, is rendered probable by the suddenness of the action.— Physical Soc., London.— Nature, May 16, 1889. J, 7. 8. Telephonic vibrations. — Dr. FroéuticH attaches a small mirror to the iron plate of a telephone and from this the light of an electric lamp is reflected to a polygonal rotating mirror, from which it falls on a screen. The vibrations of the plate were thus made visible on the screen, and since each side of the polygonal mirror cast its own image, when the mirror was rotated the curves were seen moving over the screen. The more rapidly the mirror was rotated the slower did the curves move over the screen, and when the rotation was as rapid asthe vibration of the plate, the curves became stationary and could thus be exactly observed and drawn. These luminous curves could also be photographed. The speaker had employed this method in a series of researches on certain electrical phenomena which might influence the efficiency of the telephone. Thus the action of alternating currents, of self induction, of the rise and fall of the current on making and breaking, of the introduction of electro- magnets, and of other conditions, were studied by means of the altered mode of vibration of the telephone plate. The speaker had further obtained a graphic record of the vibration of the Geology and Mineralogy. 1K telephone plate when vowels and consonants were sung and spoken into it.—Physical Soc., Berlin.— Nature, May 16, 1889. Jas 9. On an Electrostatic Field produced by varying Magnetic Induction.—Experiments on the subject have been undertaken by Dr. O. J. Lope and Mr. A. P. Cuatrockx. The magnetic circuit employed has a wire Gramme ring of trapezoidal section wound with copper over only a part of its periphery. The indi- cating apparatus was a suspended needle consisting of the op- positely charged bodies carried on a small shellac arm, to which a mirror or pointer was attached, and was suspended vertically in the plane of the ring. Great difficulty was experienced from Foucault currents when metallic films were used for the needle, and the magnetic properties of other semi-conductors tried com- plicated the matter. Eventually the charged bodies were made of paper in the form of cylinders $ inch diameter, and % inch long. Considerable trouble was caused by the electrostatic action between the needle and exciting coils, and various means of screening were tried and abandoned, and subsequently the wire was replaced by a single spiral of copper ribbon, the outer turn of which was put to earth. Observation.was rendered difii- cult owing to the wandering of the zero when the needle was charged. Heat also created considerable disturbance and the convection currents were cut off by a series of concentric cylinders of tin plate. The method of observation was to charge the two insulated parts of the needle and then reverse the magnetizing current in synchronism with the period of the needle, noting whether the amplitude of any residual swing could be increased or diminished according as the impulse assisted or opposed the motion. In this way slight indications have been observed, and the effects reverse when the charge of the cylinders are reversed. —Physicai Soc., London, May 11, 1889. BH BN Il. GkroLoGy AND MINERALOGY. 1. Fossil Fishes and Fossil Plants of the Triassic Rocks of New Jersey and the Connecticut Valley, by Joun 8. NEwBErRRY. 96 pp. 4to, with xxvi plates. 1888. Making vol. xiv of the Monographs of the U. 8. Geological Survey.— This very valuable contribution to American Mesozoic geology gives the first con- nected account yet published of the fossil fishes of the Triassic beds, and supplements the volume by Prof. Fontaine on the Mes- ozoic plants. The geological sketch, with which the Report opens, contains a brief history of the views that have been presented respecting the age and origin of the Triassic beds. The author, in his discussion of their age, states that owing to the small num- ber of plants from the Connecticut valley and New Jersey and the small number of fishes from Richmond, Virginia, a satisfac- tory comparison is not possible. Only one species of fish, Catop- terus gracilis, is certainly known to be common to New Jersey and Richmond, though Jschypterus ovatus, if identical with a fragment referred to Tetragonolepis by Egerton, may be a second. 78 Scientific Intelligence. Among the plants of Richmond and North Carolina the follow- ing have been found also in New Jersey or the Connecticut valley : Schizoneura planicostata, Macropteniopteris magnifolia, Clathropteris platyphylla, Bambusium Carolinense ?, Palissya Braunii. Pachyphyllum ( Cheirolepis) Miinsteri, P. brevifolium Newberry, Diodnites longifolius Emmons. The age arrived at, for the beds is that of the Rheetic or Upper Triassic. Dr. Newberry mentions his discovery, many years since, of Triassic plants in New Mexico, at the old copper mines of Abi- quiu, and at the Los Bronces on the Yaki River in Sonora, and the important fact that among the species four of those from Los Bronces are also North Carolina species: Pecopteris bullatus Bunbury, P. faleatus Emmons, Teniopteris magnifolia Rogers and Otozamites Macombii, which last was also found at Abiquiu. The Abiquiu beds are in the upper part of the Triassic formation (there 2000 feet thick) and directly under the Dakota group of the Cretaceous. The fossil fishes described belong to 28 species and half of them are new. The genus Diplurus, a new Ccelacanth genus, contains one species, D. longicaudatus Newb. ; Ptycholepis, one; P. Marshii Newb.; Dictyopyge, one; D. macrura Egt. which is the most common species in the Richmond basin, Acentrophorus one ; A, Chicopensis Newb.; Catopterus, six; and Ischypterus, eighteen. Of these, as the Report states, Catopterus gracilis, C. anguilli- formis, C. parvulus, C. macrurus (Egerton’s Dictyopyge ma- crura), Ischypterus macropterus, I. ovatus, I. Agassizit, I. par- vus, I. Marshii, were described by Mr. W. C. Redfield, the first early systematic worker on these Triassic fishes, and one, Ischyp- terus latus, by J. H. Redfield. The fishes are finely figured on twenty of the twenty-six plates. The Diplurus longicaudatus is grandly exhibited full size on the folded plate, pl. 20, though 21 feet long. The other plates are occupied with figures of the fossil plants. 2, Map of the region of Duck and Riding Mountains in Northwestern Manitoba ; by J. B. Tyrrex1, Geol. Survey Canada. —Duck and Riding Mountains are elevations rising from 2000 to 2700 feet above tide level just west of the Winnipeg region. The Map has a special interest because of its contour lines and the bearing of the facts on the western boundary of the Quater- nary Lake Agassiz. The “ancient beach,” a gravel ridge, has, near longitude 100° 20’ W., 51° 15’ N., an elevation of about 1084 feet above the sea level, and 50 miles to the north at 52° N., in longitude 100° 40’ W., 1201 feet. Another similar ridge about a mile west of this is 50 to 75 feet higher in corresponding posi- tions. The author discusses briefly the condition of the ancient lake or lakes, the glaciers of the country, and the question as to changes of level over the region. 3. Bulletin of the American Museum of Natural History, Central Park, New York City. Vol. ii, No. 2, March, 1889.—This number of the Museum Bulletin contains two papers by J. A. Miscellaneous Intelligence. 79 Auten on Birds of Ecuador and Bolivia, and four by R. P. WuitFiIEtp, illustrated by seven plates, on new Calciferous fossils of the Lake Champlain region, on