JOURNAL OF SCIENCE, JAMES D. anv E. 8. DANA, anp B. SILLIMAN. ASSOCIATE EDITORS Prorgessors ASA GRAY, JOSIAH P. COOKE, anp JOHN TROWBRIDGE, or Cameriner, Prorrssors H. A. NEWTON anp A. E. VERRILL, or New Haven, Prorrssor GEORGE F. BARKER, oF Puitapetpata. THIRD SERIES, VOL. XXII.—([ WHOLE NUMBER, CXXII.] Nos. 127—132. JULY TO DECEMBER, 1881. WITH SIX PLATES. NEW HAVEN, CONN.: J. D. & E. S. DANA. 1881. Missour, Boranicay GARDEN Liarary CONTENTS OF VOLUME XXIUL. s NUMBER CXXVII. rs ary 3. Bete Kn to Meteorology; by Ex1as Loomis, With Piste do ee II. ieee tes as an element of danger in Mining; by H. C. Ill. Notes on 1 Mineral Localities in North Carolina ; “by W. IV, Vatietion in Length of a Zine Bar at the same Temper- ature ; jis AOMENOUM ce poke Vhs wc ee gue sna V.—Restoration of Dinoveras mirabile; by O. C. Marsu, With Plate IT, . - GR ae ee ee zn ne ee or Kerosene Shale” of New South Wales; OV Biv emer oe ee oe ee VIL. — Meteorological Researches, Part Il. Cyclones, Torna- and Watersponts ; by W. Fania, 2. vied VIIL. —Mageti Observations made ae Davis peg in August and September, 1880; by O. T. SHerMAn, - ---- IX.—Cr vetalline form of Sipylite; by J. W. wat ee .—Observations on the Structure of Dink voph sider ‘and its affinities with certain Sponges; by R. HITFIELD, -. 53 XT. BPH aha ta Rocks of Southeast Kansas; by G. C, Bro ee XIL lee Tertiary ‘of the ( Gulf of Mexico; by E.W. Hirearp. With a map (Fiste IIT), 0 2 ew oe ene oe XIII. ste te Face fhe sg County, Va.; by J. L: Se ee ae XIV. ct eeqdols of New y Mexico; by B. SILLIMAN, . eee SCIENTIFIC INTELLIGENCE, Chemistry and Physics. —Free Fluorine in Fluor Spar, Lonw: Arsenobenzene, MICHAELIS and ta 71.—Transformation of Dextrose into Dextrine, Muscunus and Meyer, 72 LS Pemisthinaie Acid, Lewes: Photographies, EL. WILSson, 73 Sects of i hl . LippMANN: Inverse Electromo- tive force of the Voltaic are, 74.—Ste Photo graphy, H. DRAPER: Weather arnings, B, Stewart: Storing of Electricity, ’ iL Faun lv CONTENTS. Geology and Natural History —Geology of British Columbia, G. M. Dawson, 75.— ibbea Car n Miocene path Geological Survey of New Jersey. ml 1880, 77.— Heulopical Surv vey of P reat rane ngs rey of the Oil Regions of Warren, | Venango, Clarion and Bu tler Cou by J. F. CARLL: °'Statistics = | ee of fadlatia for 1880: p eectlauat a ties Earth’s Surface, N. 8. SH4 | ent: vis, 78.—The Trilobite, C. D. Watcorr, 79.—Ge ological Sutra of ite E. A. Sira: Felsites and their associated rocks north of Boston, J.8. Daaan: —— sur oi tags sp aitoes d’Altération des Dépots superficiels, fi. VAN DEN Bre Application of ‘a solution of mercuric potassium iodide in mineralogical ae lithological rset tions, V. Gotpscumipt, 80.—Deer horns — impregnate with tin ore, J. H. Contins, 81.—Microlite from a eape County, Virginia os pneiia. | Widerneds the food of some young fishes, 82. Astronomy.—Figures of the planets, 82.—Observations of the Transit of Venu “2 cays OMB: "Observation of Double Stars made at the U. S. Naval Obectea ry, A. Hab kon: ‘Selif ge ah a pgaons Sketch of the Boston Society of ; Natural History, T. T. Bouvé, 85.—American Association at Cincinnati: On | the so-called Cosmical Dae i pene 86. NUMBER CXXVIII. : 2 Arr. XV.—Modification of Wheatstone’s Microphone and its ches; by A.G. with a modified form of eae es ; by OLN. oop, 90 Gort stadt Series; by J. "D. Dist 103 XX, sorted Meteoric Tron, of unknown locality, i in the Smith- nian Museum; by C. U. Suepar, . 119" XXI—_The relative motion of ip oats and of the Luminif: 5 erous Ether; by A. A. Micu . 1200 XIL.—Observations on the Light of + elescopes used as : Night-Glasses ; by Epwarp $8. Hoxpen, --.. -- eo -XXIIL—Nature of Dictyophyto P. Wurrrierp, .. 132 by R. ek ae ee of the Soeeian of the Comet of June, 4 ; by Henry Drarer,. -o.- 19% XY. — Stason 0 Observations upon ‘the Comet b, 1881; XXVL —Observations of Comet , 1881, “made at the United States Naval Observatory ; by Wa. Harkness, --. 18 XX VII—Observations on the Comet 1881 6; by Lewis Boss, 140 og prea aetiga of Light from Comet b, 1881 ; 3 by A RI ES SISA ASO cals ange biota aut nce ce SNe ee ea 142. | SCIENTIFIC INTELLIGENCE. Chemistry and Physics.—Ozone as a cause of the Luminosity of hago | CHAPPUIS: Appearance of Nitrous Acid during wo Eva aporation of Water W ARINGTON, 145.—Boron hydride, Jonus and TAaYLo St ha 0 gt Carbon Siadenina “ALDARY : : Hlectric Absorption = cat & {. A. Rownanp and E. H. N ia smission a radiation of low re emuapeoead throwgh peg ABNEY and Fx NG: Conservation a Klectricity, Lippma ing - of Ice, WULLNER ay ee weight of Uadintiinn Bivierieaton, CONTENTS. Vv Geoloyy and Mineralogy.—Terraces and Pcemaceg ego lines ce Strandlinien ") KARL PETTERSEN, 149 ee d from some “Forts vitrifiés France, M. Davpree, 150.—Pre-glacial oo of the rane ot Lake Erie, J. W. SPENCER, 151. —Laccoliths ( Aes Uaccolites) in Japan, G. H. Kinanan: Iron Ore of Iron Mi ne bee Cumberland, R. oe tens ie field, Texas: Report of the Geolo ogic al Survey of Pen “gle ania, F. PLATT J. P. WeTHERELL, 152.—Land- plants i in the Midale Sacdhgee of N orth, Wales, “TL Hicks: Mee tbat a Mg Per- mian taba oT E. D. ek Life- History of Spirifer is WILLIAM : Geological ‘Seles of Peas. Optical Characters a ~Oryetiliinis System "of some im rae coors 8, 153. a Spall of new minerals, 255.— Dawsonite from Tuscany: Vanadium Minerals from oc Zinn, eine geol- ogisch- aoriewaon niche. Moncouihe, E. Rey 57. sein and Zoology.—Marine Algz of New England, w. G. Fartow, 158.—Das m de es Medusen von E. bigs kel, 160. — Reptiles and Fishes in the Museum of ‘Com mp. Zoology, 8. GARMA : Dredging along the Fel a of U 8. by Steamer Blake, 162. HC with note on Toxodon, E. D. Copz, 163. schon: BG nmmaba ye Spectrum of Comet 1881, 6, W. east Notice of the Comet. . Burton, 163.—Observations on the Comet, W. H. M. Curistte, 164, Micitcaous Scientific pipe Aga Tg oan oh Polar ore s occupied by the Signal Service, 164.—Smithsonian Institu Endow merican Chemical Bodoni: 165.—J. Lawrence Smit th’ 8 Collection of arnicrale nS Meteor- ites, 166. Obituary— Achille Delesse: Deville, NUMBER CXXIX, Page Arr. XXITX.—Benjamin Peirce, - XXX.—Emerald-green Spodumene from Alexander County, North Carolina; b ‘ sie —Objects and cocoa of Soil Analyses ‘by E. W. biasing Beek on ee ee XXXIL — Mineralogical Notes; by B. Stiriman, ......-. 25 XXXIIL—Liquefaction and Cold pred ced by the miuruat reaction of Solid Substances; by Evetyn M. Watron,. 206 XXXIV.—Spectrum of Arsenic ; : by ive Wi Huntineron. WEED 2 IAGO BY foo i I we ne oh an ne we eee 214 SCIENTIFIC INTELLIGENCE. gee Abe and Ek ae eich ous Oxidation of Mercury and other Metals, —Hesperidin, a Glucoside of the Aurantiacew, Tiemann and Wi a8. ser fan, ‘of Volatile Organ Base es, MEYER and TREADWELL: Phot ometry - the Fraunhofer lines, Vir : Intensity of Sound, OVERBE 9.—Reversal of the e lin es of Metallic opiate Liverne and Dewar: Change — SS ae Poynting, 220. Geology and Mineralogy.—Geology of the Province of Minas Geraes, 221 Prog: gp of the Eruption on Hawaii, 226.—-Glacial drift on Mt. K E N, : 0. f i i Fe bee sil Plants from the Lignite Tertiary rhein hn Roches Percées, Souris River, Manitoba, J. W. Dawson, 233.--North Am n Mesozoic and Cenozoic Geol- rom on ertoon System of Scotlan = emer. pa aye Loxolophodon and Uintatherium, H. F, OsBorn : Vanadinite in “Arizona, a W. P. Buaxg, 23 Vi ; CONTENTS. Botany and Zoology. ~-Monographize Phienogamarum, DECANDOLLE, 235.-—Arbo retum Segrezianum, A. LAVAULEE, 238.-—Bri Moss-Flora, R. BRAITHWAITE: Butterflies, their Structure, Changes and Life histories, S. H. ScupDER, 239. Misscellaneous Scientific Intelligence.—Meeting of the American Association for the elegr: Exact Sciences, Biographical ee Literary, OdGENDORFF: gr anes a Re Cotton Production of the State of Louisiana, E. W. hird Bress aie Academy of Turin, open to Scientists aiid riveutcre pe ‘at Na- tions, NUMBER CXXxX. Page Art. XXX V.—Cause of the Arid eieete of the Western por- tion of the, United, States; by C. E. Durron,__.-_----- 247 XXXVI.—Embryonic Forms of Trilobites from the Primor- iat ocks of Troy, NN. ¥.;-by 5. .W. Vorb, ...-- ..-..- 250 XX XVII.—Observations of Comet 6, 1881; by E S. HotpEN, 260 XXXVITII. a of the Ice-sheet at any Latitude; by ee ee 264 XXXIX. eae Or err Sonn Mienoen, vo kk 268 XL.—Notes on Earthquakes; by C. G. Rocxwoop,._-.___- 289 XLI.—Marine Fauna occupying the outer aris off the Southern coast of New England; by A. ERRILL,... 292 XLII.—Note on the Tail of Comet 6, 1881; by Lewis Boss. Meee intes V ht VE eee 303 LHL XLIV. —Geological Relations of the Limestone Belts of Westchester Co., New York; by Jamus D. Dana, 313, 327 SCIENTIFIC INTELLIGENCE. Chemistry and Physics. —Velocity of Light, RALEIGH: Movement of Sound Waves in Organ Pipes, R. K@ : Conduct ctivity of Metals for Heat and Electricity, LORENZ, S18 Miceophunis ‘action of Selenium cells, J. MosER: Stresses cause _ in the Interior of the Earth by the Weight of Continents and Mountains, G. appt a 2 age ass of Cast Iron while solidifying, M. J. B. HANNAY and R sche « and Wades cree —Origin of the — Ores of the Marquette District, Lake uperio r, M. E. WapswortH, 320.—Taconie rocks of the border of Oo in Goshen in Northwestern Connecticut: Structure and Affinities of the Monticulipora ri its poe pie , H. A. Nice sao a 322 —Ulesite in Califor nia. BLA R —F von Neapel, So-ms-LavBacn, 326.—Botanical Collector’s Handbook, W. BAILEY, 326 —— Scientific Intelligence.—Ancient Japanese Bronze Bells, E. 8. MORSE, 326, . CONTENTS. Vil NUMBER CXXXI. P Arr. XLV.—Jurassic Birds and their Allies; by O. C. Marsn 337 XLVI.—The Rvaphcier de Aurora of September 12-13, 1881; Vv J, MY SOMARBBELS (26.000 Gece 220d. Gl ee 34] XLVII.—Address of Sir J op Lubboek’: -. J Tov. teaes 343 XLVITI bis. —The Stereoscope, and Vision by Optic Diver- gence; by W. -L@OONTE STEVENS 2.2242 25..2.° 7 gee XLVIIL —The Electrical Resistance and the Coefficient of Expansion of Incandescent Platinum; by ICHOLS 363 XLIX. erp Subsidence produced by an Tee-sheet s by W. LOCC Rea iL. CUR tee el ee eee 368 i Rite on » onions Group of Southern New Mexico; SPACE gd gee 70 LI. —Potariscopie Oheeecations of Comet ¢, 1881; by A. W. pA EAA Sette gira Giles a wha Geet Rag 372 LIL _The “Relative Accuracy of different sa a of deter- mining the Solar Parallax; by W. Harxnuss ---.._.-- ee LUI.—The Nature of Cyathophycus ; by C. D. Wit corr .. 394 SCIENTIFIC INTELLIGENCE. Chemistry and nibs seni Pca ei pip of Electricians, en wae and Motion, W. TxHo. : Efficiency o f Spectroscopes, Liperci H, 396.—Niagara alls source of inate, . THomson: Change of plane of rohan of Heat rays by Electro-magnetism, L. GRUNMAC H, 397. ~Hietro-dynamie Balance, ge wa peenie condition iron and steel by magnetization, V. StRovHAL and ©. Barus: -Principles of ee Philosophy, J. P. Cooke: A Manual of gute yeni J. H. TuoKnr, 3 gy and Miner: neon and Resources of the Black Hills of Dakota, rag Saat and W. JENNEY, 399.— eke ke nee te or see eee of the Handiwork in baat soot and clay of ae e Race i Patines Atlantic Seaboard of Am CS Abe nM BW. orth on the Iron Ores of the Marcistte District, 402. ge aha and a” Che of the Marquette Region, M. oe mn acd 403. Peg nd sos mmals of the Lowest Eocene of New e Rodents of North America and Cani- de of the Loup Fork Bpodn: The Trish Elk, hei aceros Hidernius in the Ancient thar: heb ig of Ireland, W. yoo IAMS, 408.—Tertiary Lake Basin of Florissant, Col CUDDER, 409 Addr ress of the President of ie iety of London : Pantotheria » of ira Vanadates of Lead a the Castle Dome Mines in Arizona, W. P. Botany and Zoology.—Recent Papers on the Marine Invertebrata of the Atlantic Coast of eee rg snes - E. VerRIL1L, 411.—Ma) ae! of Practical aud Normal sy. Histology, T. RUDDEN, 414.— _ 8. Entomological Commission: The Hes- sian Fly, A. S. PACKA aie “i S. Morse on changes in ae and Lunatia, 415. Astronomy.—Theory of the Moon’s motion, deduced from the Law of Universal Gravitation, J. N. SrockweEwt, 415.—Astronomical and Meteorological Obser- _ Yations made during the year 1876 at the U. 8. Naval Observatory, 416. Obituary.—Dr. G. Linnarsson, 416. vill CONTENTS. NUMBER CXXXIL : puee Art. LIV.—On a possible cause of the Variations observed in the amount of Oxygen in the Air; by E. W. Morey 4 LV.—On Jolly’s Hypothesis as to the Cause of the Varia- ; tions in = Ses eda of Oxygen in the Atmosphere; E. a funk ~T ee es LVII.—A Contsibution to Croll’s Theory of Secular Climatal Change Ot a OR ee 437 LVIII. arBhe St Stereoscope, and Vision by Optic Divergence ; a EB a ee alee ie eh ee 443 LIX.—On the Selakinas: ‘of the so-called “Kames” of the Connecticut River Valley to the Terrace-formation ; by J. D. Dana 45 LX.—Japanese Seismology; by C. G. Rockwoop---------- 468 LXIL—An Apparatus for ~ Distillation of a etevsny in _Vacuo; ee igs a ge 479 SCIENTIFIC INTELLIGENCE. Physics and Astronomy.—Dynamo Electric Machines, W. Tuo : Rotation. of plane of Polarization of Light by the Karth’s Magnetism, a Bac cqu UBEREL : oe of the Ohm, RAYLEIGH and ScuusrEr, 484.—Ephemeris of the Satellites re Hi. S: PRITCHETT, 485, Geology and Natural History. — Geologiea Survey of Pennsylvania, 485.—First olay Report of the U. 8. Geological Survey, C. Kine: The Kames of Maine, G. H.8 , 487.—Geology of Staten Island, N. L. Brirron: Apu 8, d D. ZaccAGNA, 488,—Jelly-like carbonaceous mineral resembling dop- plerite, from Scranton, — , T. Coop: meralds from Ale Count North Carolina, W. KE. H1p 89. ef notices of some recently described crop 490.—Artificial formetinn of the Potash-feldspar, Orthoclase, C. FRIE- pp aneemae English Plant-names from the Tenth to the Fifteenth Contu ury, J. 491.—Familien Podostemacez, H. sg hes mows la Bo lciane et la m morphologie des ferments alcooliques, HE. C. HANSEN, qu —QOn an Organism which penetrates and excavates Siliceous Sp onge- peiciles P. M. Duncan, 493.—Bulletin of the Museum of Comparative sh! at Harvard os aee The Palzocrinoidea, WACHSMUTH and SPRINGER: Cosmos les Mondes ; _ Index to NG xxii, 495. ERRATA. P. 186, 3d line from top, for “ type are” read “ type, are.” t 181, 5th line from bottom, for ‘ effected” read “affected.” 12th line from bottom, after — Mayer” the sentence should be contnuovs: thus “Adolph Mayer, I find, e P, 191 i, 7th line from top, for “clay, permeating” read “clay, but permeating.” Pp. 191, for ‘differing so in” read “ differi : 199 2, 11th line from top, for “ proportionstely” read. FS Apa bine nas P. 240, 4th line from bottom, for Capt. W. H. Dow, read Prof. W. H. D P. 286, 19th line from bottom, ye “ Prototheria ”’ read “ Pantotheria.” Sane Se ie ie ciics uneSaa > a cae a ee a aunsssddd NVA oL9 Gh bh eg LB oc6 46 PrAus ZOT oll LW 08 0% bo . 2 ey, $O'08 é \,, Ls ef Q . \ ae i asa ae ice VIONMIGN: ae ie td Lex pve ry 1ANOS: ida “HWNNYAYS e = uy 06 ae WiSNony AS pe © ITMAXONY - 91a 2319 Nes 3d vy 6 " oe cS) § ) NOL s avnvianl ¢ ee it \ | id Sy N nviaAat2 vO Yd HLy Ws, Re 003704)» cova on e > q 10 wey We OF O-oe sett ff oF a) : j s VIN ms ZwauLnon ana Oyn* x «a ano vNIgW oh eae) : Sh Ss, Se } <2 NS 2008 ws St OT oG xe) oG OL oST «O02 = .G6. 08 oSt OF oF 20S Eo ee te “OVA AHL YONA AYHHAISOWLVY SHL 4#O AMERICAN JOURNAL OF SCIENCE. [THIRD SERIES.] Art. I.— Contributions i Meteorology: being trey dete Srom an examination of th ervations of the d States Signal Service, and from ities sources; by ELias Spot Professor of Natural Philosophy in Yale College. Fifteenth paper, with Plate I. [Read before the National Academy of Sciences, Washington, April 19, 1881.] Reduction to sea-level of barometric observations made at elevated stations DuRtne the past eight years a (ae portion of my time has been devoted to investigating the course of storms in their pro- gress across the Rocky Mountains, and in my first paperastorm was traced from Portland, Oregon, eastward to Lake Superior. During these eight years, I have had the constant services of a paid assistant, who has expended a vast amount of labor in attempting to discover the best method of tracing storms across the mountains. Some of the results of these investigations have been communicated in preceding papers, particularly Nos. 8, 9 and 13. In order to study this subject more thoroughly, I have made a careful examination of the reduction to sea-level of the ometrie observations made on Mt. Washington. I first pre- pers a table showing the reduction to sea-level, according to unwoody’s Tables (8. S. Report for 1876, p. 364), for the oat Am. Jour. Sct. Sehesie Series, Vou. XXII, No. 127.—Juny, 1881. w= a 2 E. Loomis— Contributions to Meteorology. 8 Plantamour, as developed in the Tables of Colonel Williamson (Professional Papers of the Corps of Engineers, No. 15). In tween this result and the preceding gives the observed reduc- tion of the Mt. Washington observations to sea-level. The mean of the temperatures at Burlington and Portland was taken to represent the temperature at the base of Mt. Washington, and the mean between the temperatures at the summit an base was regarded as the mean temperature of the column of air extending from the summit of the mountain to sea-level. When several months of the eight years observations gave about the same temperature and pressure, they were combined in a single mean. I thus obtained thirty values of the reduction from summit to sea-level, for a considerable range of tempera- ture and pressure. In order to extend the comparison to the greatest possible range of temperature and pressure, I selected the following list of dates from the published volumes of the tri-daily observa- tions, now embracing a period of thirty-six months. 1. All the dates on which the thermometer on Mt. Washington fell ten degrees below zero, and also all the dates on which the thermometer at Burlington or Portland fell to ten degrees above zero. 2. All the dates on which the thermometer on Mt. Washington rose as high as 55°, and all the dates on which the thermometer at Burlington or Portland rose to 80°. 3. All the dates on which the barometer on Mt. Washington or at Bur- lington or Portland sunk 0°40 inch below its normal height; 4, All the dates on which the barometer at either of the sta- tions rose 0°30 inch above its normal height. These four classes together embraced 423 days. For each of these dates, the mean pressure on Mt. Washington (from the three daily peinbh seri was determined; the mean pressure at Burlington and Port- Se TE ae a TS oe a ee RR ens eee ey DS EE ge NEN ee a Oe Ee on ee a ee ee SE eae eee ee Ty ee eels eae eer et ame ey Te Fee ee ey el ee PE st ee eT es ea ee on ee Es Sta Oe E.. Loomis—Contributions to Meteorology. 8 tion to sea-level from the barometric height 22° 3 oe to 24°2 inches and from the temperature —10° to +65 order to smooth down the inequalities of the observed casi I took the mean between each three consecutive numbers correspond- ing to the same temperature, and substituted this result for the middle number. It is presumed that the results thus obtained represent pretty nearly the results which Me — peer rom observations extending over a long term of y The results thus described. are “Gehibnay in the “follonane Table, in which the height of the barometer on Mt. Washing- ton, from 22-7 to 24-2 inches is given at the top of the pte: and the mean temperature of the air column from —10° +65° is given on the left margin. Corresponding to each sa perature given in the table are four horizontal lines, the first of which (marked D), gives the reduction to sea- Jevel as com- puted from Dunwoody’s Tables; the second pig ess bat ins marked L), shows the reduction computed from Guyot’ bles founded on the formula of Laplace; the third oriageraat - (marked P), shows the reduction computed from William- s Tables, which are based on those of Plantamour; the ste horizontal line (marked O), shows ‘the reduction deduced from actual observations as above described.* n examination of this table atiows the following results: 1. Dunwoody’s Tables accord very well with those derived from the formula of oh the differences ranging from +0011 inch to —0-041 i 2. The adferaees between the formulas of Laplace and Plantamour range from +0°080 inch to +0103 inch, the reduc- tion by nese ace being on an average 0°053 inch greater than by Planta 3. The ieee deduced from the actual observations dif- fer very much from either of the values above computed; the differences from Laplace ranging from +0263 to —0°105 inch, These differences follow a remarkable law. Acociie to the formula of Laplace, when the pressure on Mt. Washington in- creases from twenty-three inches to twenty-four inches without any change of temperature, the reduction to sea-level is in- creased by gy part of its former value. Observations, how- sir, show that the actual increase in the amount of the reduc- tion is very small, being on an average only one-seventh as great * Since this article ~~ written I have been informed that the constant 6°36 inches for reducing t. Washington observations to sea-level began to be used hs. lenge Ist, 1874, and that tar the two preceding years the constant 6°31 inches ie umn of observed reductions to sea-level, which is so small an i Pinas I have not considered it necessary to re-compute the entire series of observ \eae a 4 sa Sls | | | (Be eee Fes & 9 Gas lBRERSAS' © i SOS oso lssssisss See e es : 18 2 | & | | bee [ese (EB onan SIRSRSISES 2A 5E5 Ss a2 sey GEE Gee cea CEege egieacd aces ceca cies snaneea ees cee BE BES BSE fees Pee Pees essa gzee a HibD ecleesreees neces e See Ess eas Bee RSeseess Ree Sree eeige ogg eee BRE SBSs Bee 5 C q Soe | — rE eke ular") S Bes lZz8 Bee peceeceeees i alisas SS Se ScsSze9 Geu8 = Eel Sl Saad Deo 4 ODQo SIO OO SH iOHOO S ioe coe 2 sas 2 OOO le to aoa tae Ss os os 19 %S 11D 16 39.10 ig ie ee ee eee 5 BESS S22 223 FZEE| ee 22 585 e/8935 2582/5 Saas sie beelcclececer cele Pd Beeeaers: ae SERIE y SRBS6) BE EERIES SRSESESS Bee 2 BSE Mr or ree OOO 1H OO | OOo DODD DoOoo eoos BESS ES FS loss Eee Seeclasaa ease Ses le0 serie eile Bas Bae see lseoe le DOOD Soos eposlsooolssonloseo Soo! 8010 Lok ee) aie ie OSrMErIOMWOD lOO oOSO SESS eaeeleegsleesa(eaeal 38/5823 (8322 B83 $5 BROS RRNS|FRzS A SER |S 58 eee RBS . soreese geass eelZaas eae eses eee eeesese | #32 (BES gee ae * re) * r * “ 048 ‘fy ‘070 7-096|7-123]7-1. 7/7117 /7 ae 016/7 Br 232 | 23°3 | 23-4 | 23-5 | 23-6 | 23-7 | 23:8 E. Loomis— Contributions to Meteorology. Se Sasa (sses ee suieceg ean Sosslseccsosslsseslseselscesisss Is 2bS l55S oo ae eee © [tr g |SS82 |sS33 [8383 ESE GSEs S395 252k |saSS aes 2S25\652 (22 Ss EEE BSE PPereess pec esse eens Dooolovboploooslooowoloooslsoosiose ‘sow ee eae Ee SSowla 1D DRESS — a0 = [ie 9 = S131 qe scslees EZ [228 ae 8 |E2E > EESS SE eSIRESS Goa Een Das Are eses fgiclees eae gee Iran a EE Paice ae es g |SSes Bees CESS EZR Ress Seeiesaaesaglees ESE |e s bes 2 S [ebe ieee ® WOOrIDoOSr SOOO seeulececleess ee! Besse WMO ldo wo sae eee ince =s2 5 222 ee eee 191010 =o = Qe 10 t= OD [SS So 4 eH - a wot —_ a ees PRESIECES 2o0g SeeC e203) suieee gece: jeze 228 ses ate ezE J8BE ad A = iSeS hoes Sea SRSA Rtas esas ese. See Meo lsow ae heii le aT} ca Daa = oy OR 1p g |SEBSIe ees C53 SEES |zeSeSS8e (Cag ease |s2e [828 [2s 222 22? Fee Eee Eee RIE OO Ot Scere SSS See cee esses lees Nees oes bse lisse 8.192 S56 ipipia hips > hein R CWOOMIOOCSMIOOOO! OOOO lo oodloooolowoos eos 22S lsoo leeie_| nA — deh tin — A — BSN en RS BN las IRIs IBA DIO = § | PEES CESS SZS2 SSE se Fe/5 883 [R388 B85 222 52s S [822 a ue Lee e283 Reduction to ered : barometer on Mt. Washington, elevat b iaalie | E.. Loomis— Contributions to Meteorology. 5 as that given by the formula of Laplace. The influence of mperature on the reduction to sea-level, as deduced from the shuerrasiouk differs but little from that given by the formula of Laplace. At the highest temperatures, the observed redue- tion accords saith that computed by the formula when the pres- sure at sea-level is 29°8 inches; and at the lowest temperatures the agreement occurs when the pressure at sea-level is 30°7 inches. Thus we see that the true reduction of barometric ob- servations to sea- ee for Mt. Washington depends mainly upon temperat he shasta. ows of the reduction to sea-level given in the table on page 4 are in all cases the means of a considera- ble number of observations. In some cases the observed val- ues differ very much from the means here given. In order to learn the magnitude of these differences and to study the cir- cumstances under which they occur, I proceeded as follows: I selected all those cases (for the thirty- six months of the tri- daily observations) in which the reduction computed by Dun- woody’s Tables differed by 0°25 inch from the observed reduc- tion. ‘The number of these cases was ninety-six. As this table seemed too large for publication, I selected those cases in which the difference amounted to at least 0°3 inch and for these cases the reduction to sea-level was a computed by the for- mula of Laplace. The results are given in the following table, in which column 1st shows the number of the storm; column 2d shows the date of the observation; column 3d shows the shee ed height of the barometer on Mt. Washington, not reduced to sea- level. This observed height was obtained by subtracting 6°31 inches from the published ‘heights for all dates preceding March, 1874, and subtracting 6:36 inches for subsequent dates. Column 4th shows the mean temperature of the air column from the Cae) summit to the base of the mountain column d5th shows the observed reduction to sea-level (“t-—w); column — 6th shows the reduction to sea-level computed by Laplace’s for- mula, for a height 6,285 feet, with a barometer and temperature as given in columns 3and 4; column 7th shows the reduction ac- cording to the table on p. 4, in the lines marked O; column 8th shows the difference between the numbers in columns 5 and 6: column 9th shows the difference between the numbers in columns 5and 7; column 10th shows (in hours) how much the minimum pressure on Mt. Washington occurred later than the half sum of the dates of minimum at Burlington and Portland; column 11th shows the direction and force of the wind on Mt. Washington. The number of cases in this table is 40, of which 8 occurred in November; 11 in December; 12 in January ; 2 in Febru- 6 E. Loomis— Contributions to Meteorology. Cases in which the reduction to sea-level was unusually great. it Want Mean Red. to sea-ley. | Difference. Low | iat. Waa. No. Date. Barom.| Temp. Obs. | Lapl.|Table Lapl. |Table|ret’a.| ‘Wind. 1872 Nov. 7.3) 22°78 | 30°-2 |6°49 | 6°19 |6-41 |0-30 0-08 8 IN.W. 65 8.1 “81 31-2 |6°54 | 6°18 |6°40 6 4 8 IN.W. 48 Ls. 8.2) “96 34-2 6°49 | 6°18 |6°35| -31 | 14] 8 IN. 65 9.1) 33712 99°71 |6°65 | 6°29 |6°42 | -36 | -23 8 IN.W. 58 9.2 24 99°% |6°65 | 6°32 |6°43 | -33 | -22 8 |W. 48 if 29.2| 22°89 22°0 |6°81 | 6°35 (6°53 | -46 | -28 4i1S.W. 35 9 30.1 63 10°2 |6°81 | 6-47 16°72 | -34 , -09 4 |N.E. 45 30.3 “78 9°5 |6°89 | 6°51 16°73 | -38 | -16 4 |W. 48 Dec. 5a "85 12°5 |6°99 | 6°50 |6°68 | -49 SE 4 |N. 52 3$ 3.2] 23°14 | . 26°5 |6°66 | 6°35 6°48 | -31 | -18| 4 /S.E. 60 d 4.1 "24 21°7 [6°78 | 6°45 16°55 | -33 23 4 (W. 58 4 10.1] 22°78 2 16°87 | G57 |6-76 | -30 11l{ 16 |W. 59 5 15.2) 23°12 20°6 (6°82 | 6°45 [6°57 | -37 265 7 IN. 68 6 22.2 05 1°2 |7'13 | 6°77 16°95) -36 18} 13 |W. 43 ff 24 : 13:0 7°44 }°%°00 !7-22 | -44 | -29 ? |W. 44 8 22°75 |—10°% |7°21 | 6°89 |7-16 | -32 05| 15 |IN.E. 60 9 1873 Jan. 6.2 14 5°0 16°96 | 6°54 |6°64 | +42 32 9 |W. 60 ee 06 |— 1°2|7°10| 6°80 (6°95 | -30 1S (7822 IN, 76 Il 29 40 js 247 147-6 83.16°97 | °31 17 4 IW. 54 124 Feb. 10.1; 22°96 |— 2 7°18 | 6°80 |6°96 | -38 22 TAIN Ws 7 10.8 ‘Ol 7 |'7°08 | 6°75 |6-89 | °33 2 ? IN. W. 103 March 16.2] 22°78 | 21:7 |6°67 | 6°32 |6°54' -35 | -13; 13 |W. 28 13 16.: 14 17°2 |6°88 | 6°39 16°61 | -49 971 13 IN.W. 56 it. "87 14°2 |6°95 | 6°47 |6°65 | -48 | -30) 13 |W. 56 it 3°16 17°7 (6°81 | 6°49 |6°60 | -32 O11 1a: IN. W.. 25 14 24.1} 22°99 8-0 {7-07 | 6°60 16°76 | -47. | -31) 13 |W. 48 15 Dec. 10.1) 23°33 23-7 16°78 | 6°44 |6°53 | °34 25 .W. 62 164 1874 April 30.2} 22°67 23°2 16°72 | 6°28 '6-51 | -44 | -21 4 .W. 130 30.; 42 23°5 |6°70 | 6°30 16°51 | -40 | -19 4 |N.W. 115 17 Dec. 29-2} 23°02 11°2 |6°88 | 6°58 |6°70 | -30 | -18| 18 |N.W. 80 ; “OL 5°2 2 6°87 (7-0. 35 19; 18 IN.W. 98 18 1875 Jan. 9.3} 22°70 |— 8°7 /7°26, 6:85 |7°10} -41 16 .W. 100 “91 12°0 |6°89 | 6°54 |6°6 35 20} 28 IN.W. 70 14. “82 4 3 | 6°80 |6°99 | °33 14] 28 Ww. — 19 15. “T1 |—15°5 |7-42 | 6°98 |7-29 | -44 | +13] 28 Ww. — 16. *95 |—10°2 |7°25 | 6°95 |T-14| -30 11 | 28 Ww. — L 16.3 “00 [— 7°65 17 6°92 (7-0 “32 15; 28 Ww. — 20°* | 22°91 |—11°2 17°28 | 6-96 |7-1 “32 10} 12 Ww. a 21 25.3 “O38 3°0 j6°91 3 16°68 | -38 23 Ww. 80 ; { 26.2 "95 0°0 '7°14.1 6°76 '6°91 | *38 | -23 9 WwW. 94 ary; 5 in March and 2 in April. During the six months from May to October inclusive, no case occurred in which the observed reduction differed 0°3 inch from that computed by the Laplace formula, and four-fifths of these cases occurred in : - the months of November, December and January. Fifteen of these cases occurred at the 7.35 A. M. obs.; 16 occurred at the 4.35 Pp. M. obs.; and nine at the 11 P. M. obs., indicating that the diurnal change of temperature has an appreciable influence upon this phenomenon, but that it is mainly dependent upon some other cause. It will also be noticed that in every one of. i E E. Loomis—Contributions to Meteorology. 7 these cases the observed reduction was greater than that com- puted from the Laplace formula. There 1s not a single instance in which the observed reduction was 0°3 inch less than that computed from the Laplace formula. The mean of the numbers in column Sth is 0°362 inch, and the mean of the numbers in column 9th is 07190 inch, showing that when the reduction is computed from the table on page 4, the average error is but little more than half as great as when com- puted from the Laplace formula. There are ten cases, out of 3,285 observations, in which the error of the reduction by the Laplace formula exceeds 0°4 inch, and there are only three cases in which the error of the reduction by the table page 4, ae 0:3 inch. This table is therefore a great improvemen nt pon Laplace and also upon any other table of reductions hith- seis published. these cases enumerated on page 6 occurred during the progress of storms which were generally of considerable vio- ence. In every case, the barometric minimum on ash- ington occurred later ‘than it did near the level of the sea, the average retardation amounting to more than eleven hours. In most of the cases the barometer at the lower stations had pene the minimum, and in about half of the cases had risen to thirty inches, while the barometer on Mt. Washington had risen com- paratively. little. In a large part of the cases the temperature was unusually low and the wind on Mt. Washington was very high. In two cases the temperature at Burlington was lower than it was on Mt. ee and in other cases the differ- ence of temperature was very small. In 18738, Jan. 29.1, the thermometer at Burlington was 9° lower than on Mt. Washi ing- ton; on Feb. 10.1, it was 2° lower; in 1872, Dec. 24.3, the temperature at both stations was the same ; and in 1873, March 24.1, it was only 2° colder on Mt. Washington than at Burling- ton. These observations help to explain in a few of the cases, why there was an increased pressure at the lower stations which did not extend to the summit of Mt. Washington. A cold stratum of air whose height was less than 6,000 feet, flowed along the surface of the earth, increasing the barometric pres- sure at the lower stations, but producing no Searereey effect upon the pressure at the summit of Mt. Was on. It will also be observed that in half a ete — the wind on Mt. Washington was from the northwest; and in four-fifths of the cases it was either west or northwest. The velocity of the wind was also remarkable, the average being sixty-six miles per hour, and in four instances the velocity was one hundred miles or more. In 1875, from Jan. 14th to 17th, the velocity of the wind was not reported, but it is presumed to have been about one hundred miles per hour. It is evident, dlientstorel 8 E.. Loomis— Contributions to Meteorology. that these cases of low pressure on Mt. Washington were gen- erally the result of great storms in progress, and in most of the cases the violence of the storm had ceased at the lower stations while it continued unabated on Mt. Washington. The Danish Washington are reduced to sea-level by the table on page 4, the results will rarely differ one-tenth of an inch from actual obser- vations made near sea-level. Exceptional cases will sometimes occur; but great anomalies are confined to the colder months of the year, and seldom occur except during the progress of violent storms. In order to ascertain whether the law respecting the reduc: tion of barometric observations to sea-level, which has been dis- covered for Mt. Washington, holds true for other mountains, 1 made a comparison of the observations on Pike’s Peak, when reduced to the altitude of Denver. © The altitude of Pike’s Peak, as determined by a preliminary computation which differs slightly from the final result given on page 18 is 14,056 feet, and that of Denver is 5,262 feet. The materials employed for this comparison consisted of the tri-daily observations from November, 1878, to January, 1875, and from January, 1877, to July, 1877 (22 months), and the monthly means from November, 1873, to June, 1879, published in the annuai reports of the Sig- nal Service. These materials were reduced in the manner already described in the case of Mt. Washington. The table on 9 shows the reduction from Pike’s Peak to Denver ma ed f Tables based on the formula of Laplace (Guyot’s Met. Tables, E. Loomis—Contributions to Meteorology. 9 upon the amount of the reduction differs somewhat from that given by the formula. chile the pressure at Pike’s Peak re- mains unchanged, the observed sees in the reduction to Den- and at the lowest temperatures the agreement occurs when the barometer at Denver stands at 24:45 inches. Reduction of barometer from Pikes Peak eae 14,056 feet) to Denver (elevation 5,262 feet). 4 Therm. Wel | ACR. ATS 8 BEE. LE BSS ae 10 Abt hs ee, ae L |7°651 |7°696 |7°741 |7°786 |7°830 |7°875 |'7°920 |7-965 |8°010 |8-055 |8°100 |8-145 O |7-565 |7-572 or L {7-540 |7°584 |7°628 |7°673 |7-717T |7-°762 |7-806 |7°850 |7°894 |7-938 |7°982 |8-027 O |7°511 [7-517 |7°523 0 L |7-433 [7-477 |7°520 |7-564 |7°607 |7-651 |7°694 |7-738 |7-781 |7°825 |7°868 |7°912 O |7°436 |7-440 |7-442 |7°442 |7-445 5 L |'7°329 |7-372 |7-415 |7-458 |7-501 |7°544 |7.586 |7-629 |7°672 |7°715 |7-758 |7°801 O |7°353 |7°359 |7-363 |7°364 |7°364 |7-°364 10 | L |%°227 |7-269 |7-312 |7°354 |7-396 |7-439 |7°481 |7°523 |7'566 |7-608 |7°651 |7°693 O |7-278 |7-284 |7°291 |7°291 |7-291 |7-290 |7°289 | 7-287 15 L {7-128 |7-170 )7°212 |7°253 |7°295 |7-337 |7°378 |7°420 |7°462 |7-504 | 7-546 |'7°588 O |7°212 |7-216 |%°218 |7°223 |7°228 |7°228 |7°228 |7°228 20 L |7-032 |7°073 |7°114 17-155 |7-197 |7°238 |7°279 |7°320 |7-361 |7°402 |7-443 |7°485 ee 22 TQ 1155 [TL 70 [7177 |7°180 | 7-186 | 7-188 25 L |6°938 |6-979 ee 7060 |7-101 |7°i41 |7°182 |7°222 |7-263 |7°303 |7-344 17-385 0 O87 |7-102 [7-120 |7°126 |7°127 |7-130 |7°133 6°847 |6°887 aa 6-967 |7-007 |7°047 |7:088 |7°128 |7-168 |7°208 |7°248 |7-288 70 76 , w eo onlor o os & 6°798 |6°837 |6°877 |6°916 |6°956 |6°995 |7-035 |7°074 |T-114 |7-153 |7-193 6-968 |6-976 |6°993 |7'010 |7-017 |7°030 |7-036 4 | be |@6T1 |6-710 |6-749 6788 6-827 6-866 |6-905 [6-944 6-983 |7-023 |7-062 |7-101 oni 14 16-930 |6-939 |6-957 |6-972 |6-980 45 | Le |6°587 |6626 |6-664 6-703 |6-741 (6780 |6-818 [6-857 6-895 |6-934 [6-972 fr-011 0 860 |6°867 6°908 |6°920 : 50 | Le |6°505 |6°543 6-581 |6°619 |6-657 |6°695 6733 |6-771 |6809 |6-848 |6-886 16-924 oO 6°797 |6-809 |6°842 |6°857 |6°860 55 | be [6425 |6-463 |6°500 |6°538 |6°575 |6-613 |6°650 |6-688 |6-725 6-763 |6-801 |6-838 Te 6°754 |6°772 |6°795 |6°80 L |6-346 |6°383 |6-420 |6-457 |6°494 |6°532 |6°569 [6-606 6-643 [6-680 [6718 |6%55__ ( 6°733 |6°738 |6°744 |6°750 Tn order to test the preceding results ‘idee different cireum- ei: a selected two stations near the Pacific coast, viz: Sac- and Summit. Sacramento is situated in lat. 88° 35’, te Tie St". aKa 3 is elevated 31 feet above the sea. Su ammit __ is situated on the Central Pacitic Railroad in lat. "39° 20’, ee | 10 E. Loomis— Contributions to Meteorology. 120° 5’, and is elevated 7,017 feet above the sea. At these stations meteorological observations were made three times a day for three years in connection with the Geological ae of California under the direction of Prof. Josiah D. Whitney The monthly means of the barometer and thermometer were published by Prof. Whitney in a volume entitled ‘ Contribu- tions to Barometric Hypsometry,” and the original observations have been placed in my hands by Prof. Whitney. For the purpose of comparing these observations, a table was prepared showing for each day of the three years—1l. the height of the barometer at Summit according to the mean of the three daily observations reduced to 32° F.; 2. the mean of the tempera- tures at Summit and Sacramento for each day, according to the three daily observations; and 3. the difference between the mean barometric heights at Summit and Sacramento for each day. ese results were then divided into classes according to temperature in such a manner that each class should include a range of five degrees, and the middle ts aephagelae should be some multiple of five. The observations of each of these classes were then compared in respect to Sieompitie pressure at Summit, so that all those observations which were made at computed from the formula ut Laplace, the latter shear the — reduction deduced from the actual observations. n examination of this table shows that the reduction of the : mula; and tor all earmabisateh above 40° the Sbeeryasice : show a decrease in the amount of me heer fully equal to — the increase computed from the formula. is result shows — that while the formula of Laplace gives the reduction to sea- level with tolerable accuracy when the atmosphere is nearly in a condition of equilibrium, it gives very erroneous results when ery the atmosphere is pias disturbed. While the pressure at — E. Loomis—Contributions to Meteorology. 11 Summit remains unchanged, the observed change in the rede tion to Sacramento resulting from a change of ian meee : 41 per cent less than that computed from the formula; but all temperatures the observed reduction accords nearly as that computed from the formula when the barometer at “Sacra- mento stands at 29:9 inches. Reduction v. barometer from Summit (elevation 7,017 feet) o Sacramento (elevation 31 feet). Temp. 4 | M8. | 229. 1 2SO. || QS1. | BBR. | ABS, 24. P 2eb. | 26. ° L tVot| i VoOo;t Lid . pare 4 LOL)t 214) 6 2460/6 2h) 1 OVI} t 900 25° | 6 i i Portes 037 q 016 # VUYUlLO FOUN 30 L O JO Mogsl | it Uae} l Vdd t VS) 12uUl i Lei) t 164) 4 a2igaiti 240 Oo 6997|6°989|6-975|6-953 6-936|6-928 35 L 0 GOtiZ|0 ILVUIO 4Ui0 JtUyst UVTI 7°031)}7°061/7°091 (144)t 104 O |6-987|6-976|6-967|6-948|6-930|6-911|6°889| 6'867|6°841 - L |6°794/6-824| 6-854/6°884/6-914|6-944 6°97417-003|7-033/7-063 a) 6-923 6:919|6'906|6-889|6-870 6°844/ 6°811|6-787 6-750 45 |u 6°711|6°740|6°770|6°799|6°829| 6°858 6°888/6°917|6°94716°977 oO 6'895|6-884/6°85 | |6°825 6°798|6°76616°730 6695 go | Le [6629/6658 6°685/6°717/6'746)6°715/6 8086'S 34 /6°863) 6°82 O 0 GoVD/ON O10 (00/0 ¢ 0 6 BO Mia VOY 55 L |6°549!6°578/6°607|6°636|6°665/6°694|6°723/6°752 pan 6810 O 6°720|6°698 6°667|6°633/6°597 60 L vO V7JOD)|0 DLO UtoO 672 . Soe 6-729 129 oO 6°652|6°626|6°606} 6575 ¢ g5 | Le |6397|6-425 6-454) 6-482/6-510 94 a 6651 oO 6:586|6°560|6°530|6°506 mo | 3 79|6°406|6-434|6-462|6°490/6°518/6-546 6-574 O 6-560 |6°511/6'487 6-449) v5 |b (6251 417|6°445 472 6-499 ) " |6:481/6-438 L 6180/6 6°398 6-425 1G | | 6-366} __In order to study this question under a still greater variety of circumstances I selected two elevated stations in Europe, viz: Grand St. Bernard and Colle di Valdobbia. The former station is situated in a pass over the Alps, at an elevation of 2,462 me- ters above the sea, and the station selected for comparison is Geneva, distant 55 English miles from St. Bernard'and elevated 407 metres above the sea. The gpeervarians are* : published 3 in Deleros’ Tables ‘Sm ithsonian Tables, series D, page 11), ee a - range of the PRTORICSAE from 546 to 573 aa and for a 12 EF. Loomis— Contributions to Meteorology. range of temperature from —12° to +18° centigrade. The same table shows the ee reduction as far as the range of the observations will poise Reduction wip esiahigres fice Grand St. Bernard Rofengmore 2,462 4 eters) to Geneva (elevation 407 meters). 7 fae sac. | sda. | soz. | 555. | cos. | sei. | 564. | Sev, | 57. | 5. © Jo) Le [169-44 170-37 [171-31 172-24 |173-18 |174-11 {175-05 1175-99 [17692 [177-84 O 169°83 |170°79 10| E {167-84 |168°77 |169°70 |170°62 |171-55 |172°47/173-40 [174-33 |175-26 |176:17 O |167-02 |167-99 |168-89 |169°64 |170-43 |171-19 s g| L {166-26 |167°18 |168°10 |169°02 |169-94 )170-85 |1 71°77 |272°69 [173-6] |174°52 O |165-94 |166-88 |167°76 |168°60 |169°42 |170°38|171°36 6 L |164°71 |165°62 |166°52 |167°43 |168°34 |169°25 |170°16 |171°17 |171°98 |172°88 — ©) O [164-66 |165-52 [166-37 |167-20 [167-90 |168°69 |169°57 |170°51 3 4 L |163°20 |164°10 |164°99 |165°89 |166°79 |167°69 |168°58 |169°48 |170°38 |171°28 O |163-04 |163-88 |164-72 |165°55 |166-33 |167°08 |167°84 |168-46 : _ g| L [161-70 [162-59 |163-48 |164-37 |165-26 |166-15 |167-04 |167-93 | 168" - 169°71 O 162-00 |162-95 |163-90 |164-71 |165-49 |166-27 |166°97 |167-6 = o| E [160-22 |161-10 |161-98 |162°87 |163-75 | 164-64 |165°52 166-41 [167° 2 16817 ; O 160-40 |161-46 |162-33 |163°18 |163-99 |164-80 |165°61 |166°6 = is L }158-78 |159°65 |160°53 |161°41 |162°28 |163°16 |164°03 |164°91 |165° = 166°65 — “10 159°79 |160°85 |161-72 |162°55 |163°37 |164°19 |164-90 |165°57 4| L |157-36 |158-23 )159°10 |159-97 |160-83 |161-70 |162°57 |163°44 |164°30 |165°17 0 159-43 |160°40 }161°37 |162°12 |162°89 |163°67 |164°57 — g| L [155-98 |156-84 |157-70 |158°55 |159-41 160-27 161-13 |161-99 |162-84 |163°70 O 159°77 |160°52 |161-06 |161-80 |162-58 |163°33 8 L |154-62 |155-47 |156°32 |157-17 |158°02 |158°87 |159°72 |160°57 |161-42 |162°27 O 159°30 160-03 |160-75 |161°51 |162°17 1o| E [153-28 [154-11 |154-96 155°80 |156-64 |157°49 |158°33 |159°18 |160°02 |160°87 ~ ) 158-00 |158-79 |159°63 |160°38 |161°16 1o| LE [151-96 |152°79 [153-63 | 154-46 |155°30 |156-14 1156-97 |157°81 |158-64 |159-4¢ O 157-77 |158-46 |159°14 |159°37 14] Ee (150-67 |151°50 [152-33 |153-15 |153-98 |154°81 |155°64 |156-a7 |157-29 |158°12 O 7-08 |157°77 |158°50 16] Le |149°S9 |150-21 |151°03 |151-85 |152°67 |153-49 154-32 155-14 |155-96 |15678 0} 155-31 {156-29 |157-26 1a| Le |148°12 [148-93 |149°75 |150°56 |151-38 | 152-19 |153-01 |153°82 |154-63 |155°49 ) 154:83 |155°70 We see that the observed reduction tre with the compu- © ted reduction much better than in either of the preceding cases. _ The change in the value of the rieneh due toa change © either of the barometer or thermometer is, however, a little less than that computed from the formula. e other e evated station selected is the Colle = Valdobbia, — 4 s uated abou English miles south of Monte Rosa, atan — — of 2,485 meters above the sea, and the eee it selected comparison is Alessandria, distant about 70 English ae ae elevated 98 meters above the sea. The observations are— EF. Loomis—Contributions to Meteorology. 13 published in Bullettino Meteorologico dell’ Osservatorio in Mon- calieri, and the years selected for comparison are those of 1877, 8 and 9. e observations were reduced in the manner sltagity described on page 10, and the results are shown in the following table which is arranged in the same manner as the preceding table. Reduction of barometer from Colle di Valdobbia (elevation 2,485 meters) t o Alessandria (elevation 98 meters). Ther. Cent. -—10 543. 546. 549. 552. 555. 558. 561. 564. 567. 570, 573. 198°34 |199°44 |200°53 poh 202°73 |203°82 |204°92 |206-02 |207°12 |208°21 |209°31 1970 . 196-44 197-53 36: “61 {199 a 200°79 |201°87 202-96 |204-05 |205°14 |206-22 |207°31 197-49 |197°50 1197-50 |197°49 |197°47 194°57 |195°65 ae 72 1197-80 |198°88 |199°95 201-03 202711 |203°19 |204°26 |205°34 194°67 |195°48 |196°07 |196°65 |197°13 192°74 |193°81 |194°87 |195°94 |197-00 |198°07 |199°14 |200-20 [201-27 |202°33 |203-40 192-75 |193°83 |194°68 |195-47 |196°10 |196°41 |196°52 90°94 |192°00 |193°05 |194°11 |195°16 |196°22 |197-28 |198-33 |199°39 |200°44 |201-50 190-46 |191-47 1192-49 |193-28 !193-93 |194°46 |194-84 |195-13 1195-28 189-17 |190-22 |191 31 |193°35 [194-40 |195-45 /196-49 |197°54 |198°58 |199-63 190:85 |191-54 4 |192°53 |193°04 |193°55 |194-01 |194°27 |194-53 187-43 |188-47 |189°50 4 |191°58 |192°61 |193°65 |194°69 |195°73 |196"" 190°45 191-46 |192°01 192-55 |193-06 |193°57 |194- 1 9 bam) Saag fa 6 |197°80 2 i! 185°73 |186°76 |187°79 1 |189°84.|190°87 |191°90 |192°93 |193°95 |194°98 |196-01 189-20 |189°82 |190°27 |190-98 |191°56 |192-06 |192°58 |193°1 —— 19425 “7 | uo 184-07 |185°09 |186°11 |187°12 |188°14 |189°16 |190-18 |191°20 |192°21 |193°: 188°41 |189-08 |189-68 |190°34 |190-88 |191°37 |191-8 182°43 |183°-44 |184°45 |185-45 |186°46 |187°47 |188-48 |189-49 |190-4$ ii 19251 187-69 |188-37 |189-01 |189°66 |190°20 /190 180°81 |181°81 |182°81 |183°81 |184°81 |185°81 |186°81 !187-81 |188°81 1189- 31 190°81 187-67 |188-37 |188-94 |189°59 —* Ls Ve ie.) a wo @ PE PES EH Pe Re 4 |179°21 |180°20 |181°20 |182°19 |183°18 |184°17 |185°17 |186°16 |187°15 |188-15 |189°14 ) 185°63 |186°39 |187-04 187-70 |188-20 1 {177-64 |178-62 |179°61 |180°59 |181°58 |182°56 183°55 |184°53 |185°52 186°50 |187°49 y 185'14 |185°78 |186-41 |187-06 qe) L |L 76-11 |177°08 |178°05 |179°03 |180°01 |180-98 |181°96 |182°94 |183-92 |184°89 |185-°87 oO 183°87 l184-52 185°33 |185°82 |186-22 L {174-60 |175°57 |176°54 |177°50 |178°47 |179°44 |180°41 |181°38 |182°34 |183-31 |184°28 hie 184°05 |184°21 |184°42 |184°42 | Le [L73°11 [174-07 |175°03 |175°99 |176°95 |177°91 satis diy 180-79 |181°75 eT 0 183°19 |183°14 |183°15 This table shows Sheri ante different from those of the hile 14 E. Loomis— Contributions to Meteorology. mean temperature of the air-column remains unchanged, the observed change in the reduction to the lower station reatllie from a change of pressure at the upper eee is only one of that computed from the formula. Thus we see that the re- duction of barometric observations to sea-level 7a se different aws at different localities. The following table shows a sum- mary of these results for these five mountain stations : Change of reduction depending upon ation: Thermometer arometer. Mt. Washington, v13 0°142 Pike’s Peak, 675 + 195 Summit, Cal., 590 — °866 Grand St. Bernard, 912 + 989 Colle di Valdobbia, “695 + +500 Mean, “769 + °192 Coluinn Ist shows the names of the mountain stations; col- umn 2d shows the average values of the observed change in the reduction to the lower station resulting from a change in the ail eater of the air-column, and compared with the change mputed from the formula; column 3d shows the average wits of the observed change i in the reduction resulting from a change of pressure at the upper station, and compared with the computed cha A comparison : these results shows that the temperature coéfficient emplo y Deleros and Guyot is too large; an the observed value of the reduction to sea-level would in most cases be somewhat better represented by assuming a larger value for the coéfficient 18336 meters or 60158°6 English feet adopted by Laplace from the observati ions of Ramond made aie reduction to sea-level with tolerable accuracy. The aver- age of a long series of observations represents approximately such a condition of equilibrium; but in the daily Sey Mee this equilibrium is very much disturbed. The mean between the temperatures at the upper and lower gious | ates not represent the average temperature of the intermediate column of air; and when the atmosphere is in rapid motion the down- ward pressure is modified by the earth’s rotation in a manner not represented by the Laplace formula. There is no doubt that the formule of reduction now employed may be consider- - improved ; but it does not seem possible that any single E. Loomis— Contributions to Meteorology: 15 formula with constant coéfficients should provide for the im- mense variety of conditions which prevail in the neighbor- hood of mountain stations; and we may be compelled for each mountain region to adopt tables founded upon a direct com- parison of observations made at stations of different elevations and not very remote from each other. I have endeavored to represent by formule of a different kind the observed values of the reduction given in the preced- ing tables. They may all be rudely represented by expres- sions of the form Reduction =X—Y d T+Z dB, where X represents the value of the reduction for a mean temperature and pressure; Y represents the change in the reduction caused by an increase of 1° in temperature; and Z represents the change caused by an increase of 0°1 inch in the barometer; but this formula is not sufficiently accurate to be of any use. The formula is improved by adding a term repre- senting the variability of the temperature correction. e following expression represents very well the observed values of the reduction for Mt. Washington. Reduction = 6-499 —0-0164 d T+0:°0039 d B+-0:07 sin (4°°235 dT—41°'175), represent these values with differences perhaps no greater than their probable errors. For this purpose I take the mean of all the observed values corresponding to the temperature —10°, and also determine the average correction at that temperature for a change of 0-1 inch in the barometer. I do the same for the temperature —5°, and so on through the table. By applyin the proper barometric correction, these averages are all reduc to the barometric height 23°5 inches. In the following table, column 1st shows the degrees of the thermometer (Fah.) from — 10° to + 80°; column 2d shows for each temperature the mean reduction to sea-level when the barometer on Mt. Washington stands at 23-5 inches; and col- umn 3d shows the correction due to a change of 0-1 inch in the 16 EK. Loomis— Contributions to Meteorology. barometer; column 4th was obtained in a similar manner and shows the reduction from Pike’s Peak to Denver when the barometer on Pike’s Peak stands at 17-6 inches, and column 5th shows the correction due to a change of 0-1 inch in the barometer, which correction is negative when the pressure increases. Reduction of barometric observations. Mt. Washington Pike’s Peak Sum and sea- eee. and Denver. and Sitnatenti: Therm. Barometer 23°5 inches, Barometer 17°6 inches. Barometer 23°3 inches, Reduction. Ahad hari aia Reduction. tba ks ages Reduction. Bg ng ong —10° 7-158 “0021 77600 0070 at 7054 0056 7541 0060 0 6°943 “0061 7448 0022 + 5 6°831 “0039 7367 0022 10 6°732 “0015 7°290 0013 15 6-657 0032 [227 0023 20 6°586 0032 7179 0108 6 6°520 0047 7112 0077 6:98 — ‘0180 30 6°450 0068 7-055 0086 6°942 0138 35 6374 74 6°993 0113 6°888 0182 40 6°307 “0035 6°929 0132 6°833 —°0216 45 6-239 0024 6°858 0150 6-791 0286 50 6-173 0024 6786 0157 6°742 —°'0343 55 6107 0027 6°725 0160 6°663 —*0307 60 6°037 0026 6716 0057 6599 —°0285 65 5°968 0022 6°558 —*0267 70 6520 —*0370 75 6480 80 6°432 The irregularities of these numbers may be alone takine the mean of each three consecutive numbers in ; g é formule of reduction to sea-level hitherto employed are admitted to be unsatisfactory for great elevations, it does not e toc apse that they are correct for small elevations. seem For elevations less than 1000 feet the error of reduction is less palpable than for an ralewaaion of 6000 feet, but it is probable that the error is only proportionally diminished. Height cf the Signal Service stations. In my 12th paper I gave the results of some computations sca tnd ted considerable errors in the assumed heig e of the stations of the Signal Service. The publication SR pel ee ee RO Te Se) aE ae he ey a OR EEN Ore he Hija apace i Se ea gi BE. Loomis—Contributions to Meteorology. 17 in the Annual Report for 1879 of the mean barometric heights for all the stations of the Signal Service without reduction to 1000 feet, and for which the mean heights of the barometer are given for a series of years. Column Ist shows the name of the station; columns 2d and 3d the latitude and longitude; column 4th the elevation in feet as assumed by the Signal Ser- vice; column 5th the mean height of the barometer for the entire year, as given in the Report for 1879, page 451; column 6th shows the mean temperature of the station; column 7th shows the mean temperature at sea-level under the station, de- termined in the manner described in my 12th paper; column 8th shows the mean height of the barometer for each station at sea-level. ‘These numbers were determined in the following manner. For all stations whose elevation was less than 1000 feet I took the mean height of the barometer according to the reduction adopted by the Signal Service; and for stations ele- vated more than 1000 feet I made the reduction according to the elevations as I had previously determined them. I took the mean barometric heights for all the meteorological stations of the Dominion of Canada, so far as they are published in the official Reports. For various additional stations in the vicinity of the United States, I took the barometric heights from Buchan’s Memoir on the Mean Pressure of the Atmosphere, in the Transactions of the Royal Society of Edinburgh, vol. xxv. These numbers were all represented as accurately as possible by isobars drawn upon a chart of the United States. This chart is exhibited upon a greatly reduced scale on Plate [. From this chart the most probable mean pressure for each sta- tion was derived, and the results are given in column 8th of the table. Column 9th shows the altitude of each station com- puted from the data here given according to Guyot’s Tables; and column 10th shows the altitude computed from William-— son’s T'ables which are founded upon Plantamour’s formula. The height of Pike’s Peak was obtained by computing first its elevation above Denver from the observed values of the pres- sure and temperature at those stations, and adding this result to the height of Denver computed from the data contained in the table for that station. The height of several of these stations has never been deter- mined by direct measurement so far as I have been informed. If we compare the heights of those stations which have been thus determined, as reported in Gannett’s List of Elevations, we find them to accord reasonably well with the results above given as computed from the formula of Laplace. If we take Am. Jour. caiotinene Sertgs, Vou. XXII, No, 127.—Juxyv, 1881, 18 H. C. Hovey—Danger from Coal-dust in Mining. the differences between the numbers in columns 4 and 9 for those stations whose heights have been determined by direct measurement, we shall find that the sum of the positive differ- ences is about equal to the sum of the negative differences, which seems to indicate that Guyot’s Tables give better results than Williamson’s erie and that they may be depended apor for heights deduced from the mean of a long series of baro metric observations. Stations of the U. S. Signal Service whose elevation above the sea is more th et. than 1,000 Ee ban ee Ea Temperature. Elevation. Station Lat. | Long,|Elevat'n| Mean é Barom. if E "| Sig, Ser.) Barom Sea-lev. Station.) Sea-ley Laplace. Plant’r. Pike’s Peak__} 38°8 105° 0| 14150 | 17°750| 19°2 | 55:4 | 30-032) 14054) 14116 Santa Fé --_-| 35°7 |106°2) 6851 ! 23-265| 48°8 | 58°8 | 30°023) 7011| 7029 Mt, Washing’n| 44°3 | 71°3} 6285 | 23-626) 25°9 | 45°5 | 29-973) 6286| 6319 . oe +2, 3 Salt Take City] 41:2 |112'0| 4362 | 25°642| 52:4 | 53°3 | 30°042| 4342| 4355 innemucea-j| 41-0 }117°7) 4335 | 25°621| 50°2 | 54:1 | 30°050| 4366] 4379 Boise City...| 43°7 |1 877 | 27-144) 52:4 | 52-4 | 30°060} 2795) 2804 North Platte_|41°1 |100°9| 2838 | 27°057| 48:7 | 51-7 | 30°029| 284i | 2851 ity ..| 37°61 486 | 27°381| 54:1 | 56°6 | 30°033) 2549) 2557 Bismark ___.- 8 |100°6) 1704} 28154) 41-0 | 42°7 | 30°010) 1708) 1716 Yankton ._.-|42°7} 97-5) 1275 | 28°718| 45°8 | 49°5 | 30-023) 1205] 1208 Port: Si oa. 34°7| 98°5 1100] 28779 60°6 | 60°6 | 30032) 1188] 1192 Omaha ....-. 3| 96°0 1077} 28°876! 49°8 | 50°8 | 30-030} 1068) 1072 In preparing the materials for this article, I have been as- sisted by Mr. Henry A. cogent a graduate of Dartmouth Col- ege of the class of 1871; r. Orray T. Sherman, a iT. Art. Il.— Coal Dust as an element of danger in Mining ; by Rev. H. C. Hovey, A.M. CHEMICAL action is often induced in heaps of slack, such as exist in thick coal workings, and the heat evolved may be enough to cause ignition. The danger is greatly increased when the broken coal is comminuted and floats in the air in the form of ey which under various soit doae may undergo rapid oxi atio Galloway’s experiment show that when the particles are so fine as to pass through the gauze shield of a safety-lamp, an explosion may be caused by t eir ignition. Bauerman states that in the French collieries, “several fatal a Na have been traced to the firing of coal dust from the flame of a blast, 4 ee Oe ee, ee mee te ee Ce NT Se ree. oh ee SS oes Fi it ears lei ee ean ee a le Aik ele gee Ae Sik hk a ee Sa TE Te ee ee ee Ie FT e ap ae oe SE gre RE ce SS RR SP era bet Me POE Date as Se H. ©. Hovey—Danger from Coal-dust in Mining. 19 even in cases where no fire-damp was present in the work- ings.” The influence of coal dust in spreading the effects of gas explosions is one of the subjects of investigation by the royal commission on accidents in mines, now sitting in England. My object in this article is to lay before the public, by per- mission of Mr. Edwin Gilpin, Inspector of Mines for Nova Scotia, the results of his investigation into the part played by coal dust in spreading and augmenting the late explosion in the Albion mines. _ The seam is well-known as one of the largest in the world, being thirty-seven feet in thickness, and spreading over a large extent of ground. Many million tons of coal have been ex- tracted from the various pits, since work was begun in 1807, and the mining establishment has long been regarded as one of the most complete that could be devised. The pit in which the explosion occurred on the 12th of November, 1880, was nearly 1000 feet deep, and was ventilated as thoroughly as possible by a large Guibal fan, capable of circulating 120,000 cubic feet of air per minute through the ramifications of the mine. Shortly before the accident referred to, I went entirely through the colliery, in company with Mr. Gilpin and the over- man, and we remarked the perfection of the ventilation, and the consequent absence of deleterious gases, even in the re- motest bords. On the morning of the disaster, the night watchman reported the mine to be free from gas, except in small and harmless quantities. From what source, then, origi- nated the series of explosions, that began within an hour from the time when this report of entire safety was made, and con- tinued at intervals until the mine became a furnace, whose flames could be subdued only by emptying into its burning chambers the waters of an aiacsie river? Was there some sudden exudation of gas from the solid coal, or was this explo- sion due to the firing of coal dust from a safety-lamp or the flame of a blast? None of the forty-four men who witnessed the beginning of the catastrophe escaped to explain the mystery; those rescued the shaft; and the point reached by the party was only about 600 yards in that direction. They found several dead bodies others by the after damp, but none bore the marks of fire, nor _ was the splintered woodwork of the broken timbers charred ; 20 H. C. Hovey—Danger from Coal-dust in Mining. and the conclusion was plainly justifiable that the flame of the explosion had not extended thus The walls of the galleries bad been swept clear of timber, and presented the appearance of having been brushed with a broom. Volumes of coal dust had been driven along by the the levels, into which the party sank to their knees. It was found that clouds of the finer particles had been carried to the shaft and beyond it into the main north level, where a second- ary explosion had taken place, demolishing the « lamp cabin,” burning the horses between the shaft and the cabin, and fatally burning the man aye business it was to clean and distribute safety lamps to the miners. Secondary eaplocions caused by extracted or ie geeagl gas are nearly always in the vicinity of the first one; but her a case where the second was half a mile from the first, ah & an intervening space of at least a quarter of a mile known to have been free from flame, and presumed to be free from gas, be- cause men were in it with lamps Gisch showed no indications of its presenc Water was : daneiwualy trickling down the shaft, and the ee for some distance around were very wet, hence the dust, soon as it touched the wet walls would be made innocuous; bik the fine, dry particles of carbon that were driven on into the lamp cabin were ready for ignition. It had been the cus- s occasion it seems to be certain that the ignition of the ae dna caused a second explosion; and it is probable that the same agency was efficient in producing, or at least aug- menting, the subsequent explosions that made it necessary to — the whole mine. It was as if the woncia of a gun were compo an inflammable material, which on firing the charge doubled its effect. It should also be noted that, as a pen the Albion mines were very dry, except in portions though confessedly not well understood, is worthy of attention from scientific men, and perhaps none the less so for that very. reason. 7 eae be ere a ee W. EB. Midden— Mineral Localities in North Carolina. °21 Art. III.—WNotes on Mineral Localities in North Carolina; by Ws. Hart HIDDEN Monazite from Milholland’s Mill, Alexander Co—In August Jast (1880) I obtained at this locality some very beautiful crys- tals of geniculated rutile, which had been found there loose in the soil. Permission having been obtained to work the prop- erty I succeeded on the first day’s working* in finding these rutiles in situ. In connection with the work I “panned down” some of the loose vein material, and in this manner the mona- zite crystals were first discovered. There is every probability that if the work at the locality is continued the monazite will found in place in the vein. e rock is a fest pische . : In coridaebeatitid by “panning,” say 15 lbs. of the loose vein material, many hundred minute crystals of monazite would be foun , perhaps only a half a dozen o ich . would exceed gsth inch in diameter; rarely, pe i crystals were found of $th inch in length. Under SS jee the microscope, the majority of the minute monazite crystals are’seen to be perfectly trans- parent and of a topaz color. The planes are a ie very highly polished and lustrous. The crystals are atin hy long prismatic with modified ter- ny merge the ster pile | the shape of an * The soils.of this region are the result of decomposition and disintegration on the spot; it is eee an easy task to discover the source of minerals * found on the sur : 22 W. HE. Hidden—Mineral Localities in North Carolina. The monazite of this locality, as regards occurrence and form, is essentially the turnerite of Levy, which een shown to be identical with monazite, as was long ago cade: by Prof, J. D. Dana. The mode of occurrence and the associated minerals are nearly identical with the Tavetsch, Switzerland, locality ; the titanic acid here taking the form of rutile instead of octahedrite. An analysis by Dr. J. Lawrence Smith is now under way, and the crystallography and general De ke char- acters of the mineral will be described by Dr. Dan Other localities for monazite.*—In Burke County, mpae is very abundant, particularly at J. c Mill’s gold mine in the Brindletown district. I obtained over fifty pounds of gravel washings from this mine that afforded sixty per cent of monazite. Fourteen ounces of chemica y, pure monazite were obtained here by sifting old “tailings” and picking out the largest crystals; these were sent to Mr. T. A. Edison, ale ieee the mineral for the thorina which it was su posed to contal The crystals are usually well formed and vary considerably in habit. Figs. 446 and 448, Dana, are common ey usually very small, though some were found here of 4th inch in diameter. The color ‘is light brown. The common occur- rence of this mineral in the gold gravels of North Carolina is worthy of note. I believe that pannings from any of the streams where the local rocks are mica schists would bring it to light. In the sasetnhae gravels of McDowel, Rutherford, Burke and Polk , it was noticed in every ‘‘ panning autunite, and were intimately as ociated with uraninite, gum- mite, ; garnet, etc. The de raiona ic perfect basal cleavage was commonly observed at this locality. In-Yancey County, at the Rae 't mica mine on Hurricane Mountain, I found monazite in white orthoclase. The crystals were very fine, and complex in form; specific gravity 5248. Dr. F. A. Genth has been at work for some years on the monazite of North Oarolina and has separated over a ee of the oxalates of the rare earths of the cerium roe from it. es shall await with interest the — is ddan * Geol. N. Car., Kerr, 1880, p. 84, rae W. EB. Hidden— Mineral Localities in North Carolina. 28 of the uraninite masses had a submetallic luster, quite like mag- netite, and much of it was devoid of any pitchy appearance. Gummite,* uranotil and wranochre, occur at the above mines in considerable abundance; the three minerals are so intimately associated as to be inseparable, one specimen usually embraces them all. Pseudomorphs (cubes and octahedrons) after uraninite are quite common. A mass weighing six pounds six ounces, the largest yet discovered there, was found lately in the Flat Rock mine, which is partly unaltered uraninite. According to Dr. Genth,+ this North Carolina gummite is a mixture of uranic hydrate, uranotil, lead-uranate and barium-uranate. Some of this North Carolina gummite is very beautiful; it varies in the same specimen from a bright lemon-yellow to . deep orange-red and often has a core of velvet-black uraninite. ESCHYNITE (?),—A mineral much resembling this species occurs in deeply striated prisms embedded in feldspar at Ray’s mica mine. It is associated with apatite and beryl. It has not been analyzed. The crystals are large and well formed. Some groups of the crystals weigh a pound. SAMARSKITE.—Another locality of this mineral has lately been discovered in Mitchell County. It can now be obtained in masses of many pounds weight. Hundreds of pounds are now awaiting pitcbhears At the new deposit there is found asso- ciated with it a light brown, resinous-looking mineral of high specific gravity which may be massive hatchettolite, or a new plane between R and R in the —4 zone; also to certain in- verted (depressed) triangular markings like those on crystals * Locality discovered by Prof. Kerr in 1877; see this Journal, xiv, 496. a: Geol. N. C., Kerr, 1880, page 34; also American Chemical Journal, i, 87, $ Geol. N. C., Kerr, 1880, page 87. 9 W. EB. Hidden—Mineral Localities in North Carolina. of diamond. The basal truncation and the (new ?) plane in the —4 zone occur usually rough, though in two instances they were well polished planes. Fig. F has the dihexagonal pyramid in the 7-2 zone. Fig. having the planes 2-2, 3.3, and 4-4* beveling every pris- matic face at its intersection with Rand —1. It also has other interesting rare planes. This crystal was. perfectly pellucid, had a beautiful yel- low tint and all its planes highly polished. Fig. I illus- trates a form not uncommon in North Carolina. Often the cap or terminal crystal is strongly in contrast with the prism in color and transparency. Large groups are often found | showing this second formation in parallel position. the figures were drawn directly from the crystals and are of natural size: the determinations of the planes were made * More probably 6-$ and 8-§. + Geol. N. C., Kerr, 1880, page 88. W. BE. Mdden—Mineral Localities in North Carolina. 25 very coarse file. As yet they have not been found of sufficient depth of color and transparency for use as gems, but are quite unsurpassed by any beryls heretofore found in the United Stat hose occurring in thesoil have weathered out of cavi- ties in the rock where they. were formed. They were never imbedded, as some late work at the locality has well proven. Heretofore the only dependence for them has been the soil ; now a narrow vein bearing them has been found by the writer and a shaft twenty-four feet deep has been sunk on it. It was the beautiful color of these beryls that prompted the work that so unexpectedly yielded the new variety of spodumene.* There are good indications of yet finding here the true beryl emerald, and it is with this end in view, coupled with the mining of © the new spodumene emerald, that the writer is now at work in this State. PiatinumM.—A diligent search for traces of this metal for five months in the auriferous regions of the Southern States in the interest of Mr. T. A. Edison resulted in finding no traces of its existence. The five reported localities in this State (N. C.) were carefully examined without success. To the generous publicity that the late Professor Humphreys and Mr. J. Adlai Stephenson have given to their mineral researches in North Carolina, and to the sight of some of the many beautiful specimens they have sent north, the writer owes the impelling motive of his going to that State and the knowl- edge which has enabled him to succeed in his explorations. Stony Point, N. C., Nov. 20th, 1880. * This Journal, vol, xxi, Feb., 1881, 26 C. B. Comstock— Variation of a Zine Bar. Art. 1V.— Variation in Length of a Zine Bar - the same Tem- perature; by Gen. C. B. Comstoc {Communicated by Authority of the Chief of Engineers, U.S. A.] Tue U.S. Lake Survey possesses a steel] normal meter des- ignated as oe 1876), and a meter designated as (M. T. 1876), composed of a bar of steel and one of zinc so arranged as to form a metallic ronmhey tomnsea Both were made by Repsold. the essential parts are tubes o cast iron four meters long, each containing in its interior a steel and a zinc bar arranged to form a metallic thermometer. Irregularities in the results of comparisons of two bars in the same tube, which were very marked functions of the temperature changes, led to an exam- ination of the question whether a zine bar has always the same length at a given temperature. The results seem to show con- clusively that it has not. I have not met elsewhere with com- parisons establishing such a change; if they have been made, ese comparisons may give additional data. Mr. E.S. Wh eeler, who made the larger part of the comparisons, first called my attention to the indications of a set shown by the ordinary comparisons. As to the accuracy of the comparisons it may be said that they were made with an apparatus constructed by Repsold, in a comparing-room lined on all sides with saw-dust ; that this lin- ing reduces the diurnal temperature fluctuation to 0°83 F.; that the changes in the external mean daily temperature rarely pro- duce a change in the comparing- box exceeding 2°5 F. per day; that but two visits were made to the comparing- -room in a day; that the probable error in the result of one visit and compari- son of two steel bars one meter long is about 1"-9 (microns), and that artificial heat is not used. Temperatures were deter- mined by thermometers whose probable errors do not exceed 0°05 i one lying on each meter = In the experiments with the zine bar of (M. T. 1876), this meter was alternately heated and cooled, and after each heating periments, its i gay varying in that time only about 3° F. In heating (M. T. 1876) it was taken from the ee room at a temperature of about 36° F. to another room kept at a temperature between 70° F. and 80° F. for realy rs or more, then it was replaced in the comparing-box, where it cooled slowly to the temperature of the comparing: at dhe same Temperature. 27 room in about twenty-four hours. Comparisons with (R, 1876) were made during this period and for three days or more after- ward. (M. T. 1876) was cooled from the ‘ertdetaanna of the comparing-room to about —8° F. by being placed for about twenty hours in a tin case surrounded by a mixture of snow and salt. Then it was placed in the comparing-box, allowed to approach the temperature of the pope room, a and compari- sons were made as before with (R, 1876). Temperatures of greatest cooling and heating were taken with maximum and minimum thermometers. rom comparisons at both high and low temperatures, the relative lengths and expansions of (R. 1876), (M. T. 1876) steel bar, and (M. T. 1876) zinc bar, are approximately known. They — are, (R. ee bar of (M. T. a Oe 0"-39 (-—32°); zine bar of (M. T. 1876)=steel bar of (M. T. 1876)+267" 5+10°15 (t—82), in which expressions ¢ is the temperature in Fahrenheit degrees. The residual errors have been computed with these values. As the temperature-range was small during the comparisons given in the table, slight errors in expansion values will have little influence on the variations in the residuals. In the following tables, the first column gives the date of comparison; the second and third give the temperatures of mercurial thermometers lying on the two meters; the fourth gives the residual errors of the comparisons. of (R. 1876) and steel bar of (M. 'T. 1876) in the sense computed minus observed ; and the fifth gives the residual errors of the comparisons of (R. 1876) and the zinc bar of (M. T. 1876). The section of these bars is 18™ by 27™™. In computing residuals the tem- perature of (M. T. 1876) is s taken as the temperature of both meters. From the residuals, considering only those comparisons forty-eight hours or more after the heating or cooling had ended, it is seen that the zinc bar of (M. T. 1876), when it is heated for twenty hours or more to a temperature of 70° F. and then is allowed to cool to its original temperature, 36° F., has a certain length; that if it is then cooled for twenty hours to a temperature of =§° F., and afterwards is allowed to return gradually to its original temperature of 36° F., it will have a certain other length; and that these lengths at the same temperature may differ by fifteen microns. Both (R. 187 6) and the bars of (M. T. 1376) were freely exposed to the air inside the comparing-box. If any large gas bi the appa- rent change in length of the zinc bar of (M. T. 1876) was due to temperature errors, the residuals of the steel pet should show it at least in part. 28 C. B. Comstock— Variation of a Zine Bar Tables giving dates, temperatures and residuals of comparisons of (R. 1876) a cooling of 1. (M. between 70° and 8 and (M. T. 1876) made after periods of heating and (M. T. 1876.) Preliminary reduction. serait pee Feb. 7 to Feb. 14, 10.50 A. M. and kept at temperatures , (R. 1876)—(M. T. iv T. 1876) .— Date-of Tempera- | Tempera- 1876), computed, |T Pie? compte Domuriaon ture o ture of | minus (R. 1876)— mint on 1876), Peer (Ge S876 OL: T.71G2) (Mt. T i870), aiiee observ bane 1881, ° ° lad B Feb. 16, 9.14 a.m.) 37°02 F.) 36°91 F. —0°4 —18°6 4 16, 8.19 P.M; 36°92 36°81 —17 —17'8 oe ty Silke As | oe be 36°41 —0°4 —17°6 67, 7.58 P.M) + 36°32 36°21 —0°4 15°8 “18, 9.35 a. M.| 36°12 36°21 +0°3 —14°3 18, 8.49 P. we}. 36°32 36°21 +1°2 —17'5 19, 9.25 a.m) 36°37 36°31 +3°0 16°4 “ 19, 8.05 P. M.| : 36°42 36°41 +0°5 —14'4 20, 10.38 a.M.| 36°32 36°21 +17 -—-15°6 20, 8.37 P. M.| 36°42 36°41 +13 12° “ 21,:9.66 a. Ml 36°62 36°41 +3°2 —14-2 ue 21;''8,09 Pp. Mi} 36°62 36°61 +1°0 —13°9 22,10.12 aA. M.| 36°72 36-71 —]2 13°7 “ 22, 8.44 P.M.) 37°12 37°21 +0°9 —12°3 He 94. 9.32 a. S788 27°26 —0°9 —15°3 ey hiaaiey " 3T-07 37-01 +11 148 Oy 24. otk 36°52 36°51 +1°4 — 13°8 2. (M. T. 1876) cooled for 23 hours: Feb. a 10.00 a. M. to Feb. 25, 9.30 4 and kept at temperatures between —1° and —6° F, ° ° Be ' Feb. 25, 7.22 Pp. M.| 36°52 35°42 +21 +2°4 Hay Oia wk 34°91 34°82 +2°4 —0°5 “26, 9.38 P.M.) 34:91 34°82 +40 +1°6 6 2%, 10.22 a . 35°31 35°22 +04 +0°3 He 2, (4382 35°91 35°81 0°6 id 17 - (M. T. 1876) heated for 22 hours: Feb, oa 11.30 A. M. to Mar. 1, 9.10 A. M., being kept at temperatures between 70° and 80° F, ° ° # p Mar. 2, 9.11 4.M.) 37°02 36°96 0-0 —15'8 “9. 9.04 POM. 36°72 36°61 +0°3 — 1653 “ °8, 9.0% 4. | 8632" |’ 3621 | —0°2 —16'0 « 3, 8.51 P.M} 36°32 36°21 | 0-0 157 “ 4, 9.09 a. M.| 36°32 36°21 | 24 ths 4, (M. T. 1876) cooled for oi — Mar. 3, Pty A. M. to Mar. 4, 9.30 A. My being kept at temperatures be betw: and — pe Ie r Mar. 5, 8.58 P.M.| 36°72 | 36°61 + 2°6 + 6°6 "6, 0.50.4. Mi 36°82. |. S67} + 2°2 + 6°4 +. 6, 8.04 P.M) 37°22 | 37°16 +i +6°0 “7,852 aM) 37°32 | 3721 +1'4 +5'1 e 4, 1.06 P.u 8T68 | 3t61 +2°8 +5°3 “ 8, 9.03 a.m.) 87°88 | 37°81 +3°0 +53 at the same Temperature. 29 (M. T. 1876), denotes the steel bar of (M. T. 1876) and (M. T. 1876),, the zine ea pis the symbol for micron or thousandth of a millimet The tubes of the Bépeold base-apparatus have already been spoken of. A similar experiment was tried with these tubes. The zine bars of tube No. 1 and of tube No. 2, as well as ° FF; then t was heated for twenty-four hours to a temperature between 70° and 80°, and after the heating the two zine and the two steel bars were again compared. ‘The relative lengths and expansions of the two steel and of the two zinc bars are given approximately by S’ =’, + 1518"-8 — 0%-06:, Z' =Z',+ 210"6 — 0”-44t, where ¢ is the temperature of the comparison in Fahrenheit degrees. The lengths designated by S’,, S’,, Z’,, Z’,, are each very nearly four meters, but are not the lengths used in base f bars and have been used to avoid any question of lateral . flexure. Temperatures were observed with three well deter- mined thermometers in the interior of each tube. In the following table it is assumed that the observed mer- curial temperatures are the true temperatures of the bars. The absolute expansions of the bars are known, and with them the observed difference of length of the two ‘bars is reduced to what it would have been if the two bars under comparison had had the same temperature. This is called the observed differ- ence of length of the two bars. ee it from the differ- ence of lengths of the two bars at that temperature as com- a from the equations given above, the residuals result. positive, they indicate that the sbancntian difference of iength of the two bars was algebraically too s The first column gives the date of the abiNpEtaon? the second es third, the mercurial temperatures of tube 1 and tube 2; the fourth, the residuals of the steel bars or S’,—S’, computed, minus S’,—S’, observed ; the fifth, the residuals for the zine bars or Z’, pan 7 computed, ‘minus vA ies observed. 30 ©. B. Comstock—Zine Bar Variation. PRELIMINARY REDUCTION. §7,-8’, Z’,—Z’, Date. he ta. residuals. residuals, 1881. ; P # Mar. 14, 9.40 A. M. 39°74 F. 39°82 F. —1°0 —2°3 ‘ 15, 9.39 P. M. 40°58 40°67 —3'8 —5°2 Stig. sar BOLe ae 41°79 41°80 8°9 —2°5 AT, Oot AS 41°90 41°90 7 —2°4 Tube 1 from Mar. 17, 9.30 a. M. to Mar, 18, 9.15 A. M., was kept at a tempera- ture between 70° and 80° F. Mar. 15," 8,15 Pou. 46°51 45°12 1041 _58°9 oo) WO) O44 Al 44°25 43°69 — 84 46°8 Le, eee P, We 44°02 43°52 + 0°9 —38°8 19, 8.08 P. M. 43°88 43°50 + 2°% —42°1 Dr (BOs) So Aa Me 43°66 43°37 + 46 —33°5 og 8.30 P.M, 43°70 43°45 — 6°4 —38'8 25, 10.235 A.M. 43°47 43°33 +) 3° —35°3 aeiye EO, Me 43°51 43°32 + Ll 33°4 Co 2a, ola A. Me 43°33 43°12 + 2°6 —28°8 22, 8.43 P. M. 43°03 42°90 — 49 —26°4 © 23,° SISA 42°76 42°59 — 0:6 —29'7 An examination of the residuals shows that the mean residual of S’,—S’, before heating was —5"-8, and allowing forty-eight hours to cool, that the mean residual from 9" 39" A. M., March 20, to 9" 18™ A. M., March 23, was 0”-0, differing 5-8 from the previous value, a quantity too small, in view of the very large residuals before heating, to indicate a change in S’,—S’,. But the mean residual of Z’,—Z’, before heating was —3'-1, and after heating, between March 20, a. M. and March 23, was —32"2, a change of 29". It seems, then, that the heating from 41° F. to 75° F., and subsequent cooling to to 43° F., increased the length of the four-meter zinc bar about 29", This would give a change of 7" per meter for a temperature change of 30°, or about half the ahnaiye found for the zine ml of the meter (M. T. 1876) for +75° a temperature change from —3° Sufficient data have ary yet bs obtained to determine the The question at one whether bars of other metals may have asinible differing pak at the same temperature. U. S. Lake Survey Office, Detroit, Mich., April 30, 1881. ES a aE NTE Se a OE See ee ae OE eS ER Te om TS : ; 0. C. Marsh— Restoration of Dinoceras mirabile. 31 Art. V.—Restoration of DINOCERAS MIRABILE; by Professor O. C. MARSH. With Plate II. THE order of extinct gigantic mammals discovered by the writer in 1870, in the middle Hocene of Wyoming, and named Dinocerata, has now been investigated, and all the more impor- tant characters of the skeleton carefully determined. In this peculiar group of Ungulates, there are three well-marked genera: Dinoceras Marsh, the type genus, Tinoceras Marsh, and Uintatherium Leidy. These will be fully described by the writer in an illustrated monograph now nearly ready for publication. is memoir will be based upon the remains of more than one hundred and fifty distinct individuals of this order, now deposited in the Museum of Yale College. e type species of the Dinocerata is Dinoceras mirabile Marsh, and especial pains have been taken to work out the osteology of this animal, as a key to the structure of the group. Almost every bone in the skeleton is now known by various speci- mens, and this affords ample material for a restoration which orn, as in the Pronghorn (Antilocapra Americana). The sur- face of the osseous protuberances is very similar in both cases. 32 A. Liversidge—Torbanite of New South Wales. The material now available for a restoration of 7%noceras grande Marsh, is sufficient to show that this animal was similar in general proportions to Dinoceras mirabile, but of muc larger size. e few specimens that can at present be referred to Uintatherium leave many points in its structure undecided. The type specimen of this genus is from a lower horizon than that of either Dinoceras or Tinoceras ; the evidence now at hand seems to indicate that Uintatherium is the oldest and most generalized form of the Dinocerata. specimen in the Yale Museum from near the original locality, and agreeing, so far as the comparison can be made, with the type, as four lower premolars. This character will serve to istinguish Uintathervum from Dinoceras, to which it has various points of resemblance. Tvnoceras is from a horizon higher than Dinoceras, and is much the most specialized genus of the group. Yale College, New Haven, June 14th, 1881. Arr. VI.— On the Pd Asai or “ Kerosene i asa of New South es; by A. LiveRsIpGE The so-called “ a shale” does not differ —! widely from ret ee and torban Like cannel oe) it usually appears to ‘pares melting, and emits a luminous smoky flame. When heated in a tube it neither decrepitates nor net but a mixture of gaseous and liquid hydro-carbons distils n color it varies from a awn black: at times with a greenish shade, to full black. The luster varies from resinous to dull. When struck it emits a dull hoi sound. The powder is light brown to gray; the streak shin Professor Silliman proposed the name of Wollongongite for the mineral; but this has not come into general use, neither is it an appropriate name, since the eke si sent to him was not from Wollongong, but from oe Analyses recat ee 3, From Joadja Creek, color black, brownish, sp. gr. ieee and 1°229; 4, From Murrusundi, pa a but with Whee — spec Loss 0 440 “040 1165 Volatile hyde carbons ws Bak 83-861 82°123 71°882 a ed ca 5°765 8035 7160 6°467 rye T7075 10°340 19-936 Sulphur 536 “589 “837 549 A specimen from the Hartley seam, where most free from min- eral matter, having sp. gr. 1°052, affo rded: Moisture and volatile hydro-carbons 82°24, fixed carbon 4°97, ash 12 he 100. An ulti- mate analysis of the same , dried 100° C. , gave: Carbon 69484, horde 11°370, oxygen, nitrogen, and sulphur 6'356, ash 12°790 * Abstract from paper in Proc. Roy. Soc. N. 8. Wales, Dec., 1880. a Miata sels achat 2 4 Plate Il. AM. JOUR. SCI., Vol. XXII, 1881. Restoration of DINOCERAS MIRABILE, Marsh; one twenty-fifth natural size. Pig ay it W. Ferrel—Cyclones, Tornadoes and Waterspouts. 33 Art. VII.—Meteorological Researches, Part bie ee ak Torna- : does and Waterspouts ; by Wo. F [Abstract, published by permission of CarLILE P. PaTrerson, Superintendent of the United States Coast and Geodetic Survey. ] torial and ae regions. This gives rise to an interchanging motion of the air, toward the equator below and from it above, and if it were not for the effect of the earth’s rotation on its axis this interchanging motion would be at all places in the direc- tion of the meridian, and would be continually accelerated in its initial motions, until the friction arising from these motions would exactly equal the force producing them, after which the motions of any one place would be constant, but of course differ- ent at different places. The now well- known effect of the earth’s rotation is to give rise to a deflecting force to the right of the direction of the moving body in the northern hemisphere and the iebanlle in the southern, whatever may be the direc-— _ tion of motion, Hence the air in moving above toward the poles, is deflected toward the east and in moving toward the equator below, toward the west, so that the tendency is for the air to assume an eastward motion in the middle and higher lati- tudes, and a westward motion nearer the equator. ‘These latter motions combined with the interchanging motions between the equatorial and polar pao give rise to what. are called the _ general motions of the atmosphere, depending upon the differ- ence of temperature between these regions and independent of local disturbances of temperature. The amount of eastward motion depends upon the amount of _ friction, and must be such that the friction at the earth’s sur- | face is equal to the force causing this component of motion, _ and the same with regard to the westward motions. According . a well established principles of Nashanie there cannot arise _ any force from the effect of the earth’s rotation, which by means of friction would tend to either increase 2 decrease the earth’s SPs ART ee * Coast and Geodetic Survey Report for 1878. Appendix 10. Am. Jour, re Serizs, Vou. XXII, No. 127.—Juxy, 1881. 34 W. Ferrel—Cyclones, Tornadoes and Waterspouts. eastward motions in the higher latitudes increase with increase of altitude, but nearer the equator the westward motions decrease with increase of altitude and at a certain altitude van- ish and become eastward motions. i The deflecting force depending upon the earth’s rotation 1s such that if the air on the parallel of 45° has a velocity of 54 miles per hour, it gives rise to a gradient of pressure, increasing to the right of the direction of motions in the northern hem1- sphere, and the contrary in the southern, of 0°1 inch of mercury in the distance of one degree of a great circle of the earth. This force, and consequently the gradient, is as the velocity and the sine of the latitude, and hence it is a maximum at the pole and decreases toward and vanishes at the equator. The east- t ward motion, therefore, in the middle and higher latitudes gives The regularity of the general motions of the atmosphere and of the gradients depending upon them, is very much interfered with by irregularities in the distribution of the earth’s tempera- ture arising from ocean currents, and from irregularities of understand the theory of cyclones, tornadoes, etc. _ Oyclones.—Cyclones arise from more local disturbances of tem i : ’ eart other means exactly equals the amount received, and hence there cannot be uniformity of temperature even on the same W. Ferrel— Cyclones, Tornadoes and Waterspouts. 35 latitudes, and there must be a great many local irregularities in the distribution of temperature independent of the great genera disturbance of the equality of temperature between the equato- rial and polar regions. These must give rise to corresponding motions of the atmosphere which are superadded to those of the general motions. If in the unequal distribution of temperature it should happen, as it must frequently, that there is a some- what circular area with higher temperature in the interior and with temperature gradients increasing somewhat regularly on all sides from the center outward, we should have, at least approximately, the initial condition of acyclone. There would and this by virtue of the earth’s rotation, has a gyratory motion around its center, equal to that of the earth’s rotation multiplied into the sine of the latitude of this center. Hence, as in the case of the general motions of the earth, this interchanging motion between the central and exterior part of the warmer and more rarified air, must give rise to gyrations around the center from right to left in the northern hemisphere, with gyra- tions the contrary way in the exterior part, and these gyrations in contrary directions must give rise to gradients of pressure increasing in the central part from the center outward, but in theexternal part to a gradient of pressure increasing from the outward limit of the gyrations toward the center, so that there must be a belt of high pressure with its maximum where the interior gyrations in proceeding from the center, vanish and change signs. These exterior gyrations and the gradients aris- ing from them are generally small in comparison with those of the interior, and they are generally so interfered with b humerous irregularities, that they are not readily shown by observation, but to deny that they exist, would be to deny the truth of a fundamental and well established principle in mechanics. . The increased pressure under the belt of high barometer surrounding the central part of the cyclone causes a modifica- tion of the flow of air toward the center very near the surface, for the air: is forced out from beneath in both directions, the flow toward the outward border very near the surface counter- 36 W. Ferrel— Cyclones, Tornadoes and Waterspouts. acts and reverses the flow toward the center arising from the primary and initial cause of disturbance, while the part pressed out on the interior side toward the center, combines with this flow toward the center and increases it. For the same reason in the general motions of the atmosphere the flow of air below from the polar to the equatorial regions is reversed very near the surface, arek the gentle southwest winds of the middle lati- tudes are pro The Sequel condition, found in the unequal distribution of Eiupoeseare must be regarded simply as a primary cause of disturbance, giving rise merely to the initial cyclonic dis- turbances ; for without other conditions, depending upon the ygrometric state of the atmosphere, and u upon the rate of de- crease of temperature with increase of altitude in the atmo- sphere generally in which the cyclone exists, we could have no cyclone of long continuance or of much v iolence. With a dry atmosphere the air in the ascending savbarit of the interior would cool about one —, centigrade for each 100 meters of ascent, so that the air at a very moderate elevation would be- come colder and more dense than that of the strata of the sur- rounding atmosphere at the same altitude. The pressure then of the air at the surface in the interior would become never is except in some rare cases and very near the earth’s surface only. When this would take place the initial cyclonic disturbances — from this primary cause of disturbance wou I the rate of pesmi of temperature sic de increase of aiiteds in the surrounding atmosphere generally is less than that in an ascending current of saturated air, then the temperature of the air in the ascending current, at all altitudes, must be less than that of the air generally, and hence the column of ascending air is lighter than the surrounding air, and the ascending cur- . rent is kept up as long as it is supplied with air nearly satu- rated. If, however, after a time, this current comes to be supplied with dryer air, then it has to ascend to a much greater elevation before condensation of the vapor takes place, and as z W. Ferrel— Cyclones, Tornadoes and Waterspouts. 37 it cools at the rate of 1° C. for each 100 meters before it conditions of a continuing cyclone at all, the power of the cyclone would at least be very w ere the state of the atmosphere is such, whether dry or saturated with moisture, that the rate of decrease of tempera- ture with increase of altitude is greater than in an ascending current, it is ee to be in a state of unstable equilibrium, since ing action of the currents set in motion. But an pera 9 in this state over a large area would not furnish the conditions for a large cyclone, but there would be simply a bursting up of the lower strata through the upper ones at various places, giving rise to numerous local showers, and often to tornadoes and hailstorms. In order to have the complete conditions of a rtant element, since without this we cannot have the state «2 unstable equilibriam unless the rate of decrease of tempe- rature with increase of elevation in the atmosphere generally is greater than 1° C. for each 100 meters, but where the air is saturated this condition takes place with a rate of decrease less than half as great, : rate of decrease which is often found in vapor, and the “ab sae the decrease of temperature of the air ith the increase of elevation, the greater is me power of ag clone. But without these there sid be: small gradients with no violent winds, and the depression only becomes 2 from the gradients extending over a large e equator where there i is no gyration of the area of alain: around its center in virtue of the earth’s rotation 38 W. Ferrel—Cyclones, Tornadoes and Waterspouts around its axis there cannot be any gyratory motion, but the interchanging motion between the central and external part is entirely radial. Cyclones are therefore never observed on or very near the equator. If there were no friction between the air and the. earth’s sur- face, all the conditions of a cyclone could be satisfied by case the linear velocity of the gyrations would be very great near the center. The greater the amount of friction between the air and the earth’s surface the less is the velocity of these gyrations, and the greater the inclination of the direction of motion at the earth’s surface from the direction of the the same, the nearer the equator the greater the inclination, so that at the equator it becomes 90°, and the motion, as already stated, is radial. In the exterior, or anticyclonal part, where the gyrations are reversed, this inclination at the earth’s surface is outward from the tangent. At all altitudes some distance above the earth’s surface the friction is small and the gyrations are more nearly circular, but a little inclined toward the center in the lower part where the interchanging motion is towa the center, but outward from the center above, where this motion is from the center. e : atmosphere on each hemisphere of the globe, with the cold les as their centers, are simply two examples of cyclones of this sort. The gyrations here, in the northern hemisphere, are around the pole from right to left, as in an ordinary eyclone, and the contrary in the southern hemisphere, while at a certain distance from the center, or pole, these gyrations W. Ferrel—Cyclones, Tornadoes and Waterspouts. 39 vanish and change signs, then giving rise to the anticyclonal part of the system, as in an ordinary cyclonic system. A local cyclone of this sort, with much violence or long con- tinuance, cannot take place. For if there was a central colder area which would give rise to the initial motions of such a cyclone, the air in its descent in the interior would become ° C. warmer for each one hundred meters of descent, and hence the colder initial temperature of the central part would soon be so increased as to equal that of the atmosphere generally surrounding, when the condition giving rise to initial motion would be destroyed and all motion cease. In such a case there would be no advantage in a moist atmosphere, since if it were even saturated as soon as descent in the interior would commence, it would become unsaturated. Hence we never have any violent cyclones of this sort, and nothing more than initial disturbances which continue generally only a short time. Fixed Cyclones.—Where the primary cause of temperature disturbance is fixed to one spot on the earth and kept up con- tinuously, it gives rise to a fixed cyclone. Such an example is furnished by a warm island surrounded by a colder sea. This, unless it were very near the equator, would give rise to consid- erable cvclonic disturbance, and, if the island were of consider- able extent, to an observable barometric depression. A ver remarkable example of such a cyclone exists in the northern part of the Atlantic ocean. ere, on account of the Gulf In the summer season the temperature gradients nearly disappear, and’ there is very little cyclonic disturbance over this region or barometric depression in the vicinity of Iceland. 40 W. Ferrel—Cyclones, Tornadoes and Waterspouts. circumstances connected with the earth’s surface. The primary temperature disturbance is not sufficiently great and permanent enough to hold the cyclone to the spot where it originates, and it is carried forward by the prevailing general movements of the atmosphere, and the central area of warmer air is main- tained by the heat arising from the condensation of the vapor in the interior ascending currents supplied with moist air from the earth’s surface by means of the horizontal currents flowing e them in that direction, with an inclination still toward the pole. This seems to be the general tendency of cyclones originating everywhere near the equator, but they seem to make their way through toward the pole with greatest facility on the west sides of the Atlantic and Pacific oceans, because there the genera motions of the air are deflected around somewhat toward the — con mostly, the progressive motions of the cyclones depend rather — u n the general motions of the atmosphere at considerable _ _ It must not be supposed, however, that the progressive MO- _ tion of cyclones depends entirely upon that of the air in which W. Ferrel—Oyclones, Tornadoes and Waterspouts. 41 the cyclone exists. It depends also very much upon the direc- tion in which the greatest humidity of the air lies. The pro- gressive motion of the cyclone is generally greater than that of the air, even in the upper regions, and consists rather in the continual formation of new cyclones a little in advance of the ones, the latter gradually subsiding,.and this new formation is mostly likely to occur in the direction of greatest moisture. Areas of High Barometer.—These arise from the intersecting and overlapping of the circular belts of high barometer of dif- ferent cyclones both fixed and progressive. In consequence of the gradients arising from the general motions of the atmo- sphere combined with those of the fixed cyclones and all the other irregularities, the gradients and isobars become very irregular. When to these are added the irregularities of pro- gressive cyclones following and impinging upon one another this irregularity becomes still much greater, so that it must frequently happen that there are areas in which the barometer stands higher than at any of the surrounding places, just as on a rough sea where numerous broad waves interfere and cross one another, the surface of the sea has elevations and depres- sions, not in the form of waves and troughs, but rather of ele- vated and depressed areas approximating more nearly to a circular form. The isobars of these areas are generally some- what irregular, but still as they enclose an area, and the winds, according to a well-established law, must blow with a certain to run out. If the water is entirely at rest when the flow commences, there will be only a radial and very gentle motion of the water from all sides toward the center, without any gyratory motion, but if it has the least gyratory motion in its initial state, even entirely imperceptible, it will run into very rapid gyrations before reaching the center. 42 W. Ferrel— Cyclones, Tornadoes and Waterspouis. The effect of friction in tornadoes is much less than in cy- clones. A cyclone of considerable extent may be regarded as a disk, with a diameter many times greater than its depth or thickness, and hence the gyrations are very much retarded by friction on the earth’s surface ; but a tornado is rather a pillar of gyrating air with a very small base in comparison with its altitude, and hence the retardation of the gyrations by friction on the earth’s surface in this case is comparatively very small. The gyration of the air, therefore, except near the earth’s sur- face, is very nearly in accordance with the principle of the preservation of areas, and hence the lineal gyratory velocity is very nearly inversely as the distance from the center, and con- sepa upon the earth’s rotation being nearly insensible. n account of the rapidity of the gyrations near the center ornadoes occur when, fro state of unstable equilibrium already referred to. This may e near the earth’s surface, but is most usually up in the region of the clouds, where the air is saturated with moisture, and where consequently this state occurs most frequently, since it then requires a rate of diminution of temperature with increase of altitude usually less than balf as great as in the case of dry air. hen the atmosphere is in this state the air of the lower strata, from any slight disturbance, bursts up through the upper strata at some point, and the higher it ascends the greater is the difference between its temperature and density and those of the surrounding strata at the same elevation, and hence the greater the tendency to rush up at that point. But, as in the ease of the basin of water, if the initial state of the air were that of quiescence, there would be only a radial flow of air from all sides toward that point without any gyratory motion or diminution of tension at the center, and with very little violence of motion. The velocity of the ascending current in this case would not very great since the column of ascending air would soon spread out laterally, and become too great. In order to have, therefore, all the conditions of a tornado, it is necessary to have, besides the state of unstable equilibrium, the other conditions which, as in the case of the water in the oes ote Cie ae ee a Ee yee ene W. Ferrel—Cyclones, Tornadoes and Waterspouts. 43 basin, give rise to gyrations around the central point toward which the air from all sides flows. When these gyrations com- mence above, as they usually do, since the air there is most frequently in the state of unstable equilibrium, they gradu- ally extend downward for the gyrations cause a great diminu- tion of tension and of density, and the air consequently in the center rushes up with great velocity and that below of the still unagitated strata is drawn in to supply its place, which like- wise runs into gyrations around the center, so that the gyra- tions in a very short time extend down to the earth’s surface. The whole column of gyrating air is like a tall flue containing very rarefied air, the centrifugal force of the gyrations acting us a barrier to prevent the inflow of air from all sides into the interior, and if the gyrations at the earth’s surface were as rapid s those above, it would be similar to such a flue with all the diminished on account of the friction at the surface, and this motion of the air, near the surface, is more nearly radial, or at least very much inclined inward from the direction of the tan- ie It is the same somewhat in the case of large cyclones. is much greater than it is at a moderate elevation above, and overcome the greater must be this radial component, and where there is little friction this radial component is very small and the gyrations nearly circular. ; Where the air near the earth’s surface is nearly saturated with moisture it has to ascend to only a very moderate altitude, at the outer border of the tornado, to have its tension and temperature so reduced that the vapor is condensed into cloud, and nearer the center, where the tension is diminished by the centrifugal force of the gyrations, the stratum in which conden- sation and cloud-formation commences is brought down to the case a considerable area of the earth’s surface in the central part of the tornado is covered with dense cloud and enveloped in darkness. The indrawing, gyratory and ascensional currents 44 W. Ferrel— Cyclones, Tornadoes and Waterspouts. are so strong as to draw in and carry up very heavy bodies and hrow them out above to a great distance. Sometimes the ascending current is so strong as to keep a heavy body sus- pended in the air for a long time until the tornado has pro- gressed many miles, when, after the violence of the tornado begins to abate, the body falls to the earth. Unless the strength of the ascending current is sufficient to carry the body up to an altitude where the air tends outward from the center, the grad- ually indrawing currents below that altitude keep the body near the center and it cannot fall to the earth until the ascend- ing A aie! of the current which has carried it up, is dimin- ishe Waterspouts.—These are simply special cases of tornadoes, as tornadoes are of cyclones. Where the air at the earth’s surface in a tornado is not nearly saturated with moisture, it has to ascend to a much greater elevation on the outward border of the tornado before cloud-formation takes place, and also the nearly horizontal inflowing and gyratory currents below have to approach very near the center before cloud is formed, and the nearer the earth’s surface, the nearer this approach must be. Hence, the base of the cloud assumes a funnel-shape above, with a long tapering stem reaching down to the earth or sea. A waterspout, therefore, is simply the cloud brought down to the earth’s surface by the rapid gyratory motions near the center of a tornado. is may be explained by means of a deep vessel, instead of ashallow basin, of water with a hole in the center of the bottom. If the water is allowed to run out, and it has only an almost perceptible initial gyratory motion, it finally runs into very rapid gyrations around the center, and the surface of the water and each of the strata of equal pressure under the surface, assume a funnel shape at the top and extend down to the bottom, even within the hole, in the form of a long, tapering tube. It is the same in the case of the air ina tornado. The fact that the air of the lower strata runs upward through the upper strata, instead of downward through the bottom, does not alter the case, for the gyrations, upon which the lowering of the strata of equal tension and temperature depend, are produced just the same in both cases. The stratum of the air, then, of which the tension and temperature are such as to condense the moisture of the air, assuming this shape, of course the base of the cloud assumes the same. If the dew-point of the air at the earth’s surface is . below the temperature of the air, then air at the outer limit has to ascend about 1,000 meters before cloud-formation takes place, and this determines the height of the spout. The distance from the center at the base, at which condensation and cloud-formation takes place, depends upon the rapidity of the gyrations, and this upon the amount of W. Ferrel— Cyclones, Tornadoes and Waterspouts. 45 initial gyration and of friction. In a tall, slender column of gyrating air the friction is small, and the oyratory velocity may be assumed to be very nearly inversely as the distance from the sae except very near the center, where the gyratory velocity mes almost infinitely great. Without any friction the weaterapdirt would always be brought down to the earth, it might be in the form of a mere thread, however small the ini- tial gyrations, but in nature, where friction, at least near the center, must diminish considerably the velocity of the as. this is not the case. The diameter of the base of the wa spout depends upon the gyratory velocity, and where pe on account of friction near the center, is not sufficient to bring the spout down to “ene surface of the ‘earth, it is seen merely as .a funnel-shaped clou Small waterspouts sihcon are seen upon the sea or small lakes in perfectly clear and calm weather, arise from a state of unstable equilibrium of the clear but nearly saturated air near the —— of the water. The principle of their formation is the s but a greater rate of decrease of temperature with ices of altitude is required, than when their first formation ing currents so ong as the rain is not carried up where the air ows out from the center. Calculation shows that the amount of rain condensed from nearly saturated currents of air with such velocities as must exist in the central parts of tornadoes is enormous. The water cannot fall in drops on account of the strength of the current. It therefore accumulates in the body of the cloud, and especially at points where the ascending current is least, until the weight of water becomes so great that itis poured down t rough the air in streams. Where these streams strike the earth’s surface they excavate great holes in the earth, often several yards deep, and if this occurs on a sen of these holes are often cut down almost expenitieciahs while leaves and other light substances, where these holes occur on mountain sides, remain undisturbed near the border on the upper side. The ascending current keeps rain-drops from fall- ing, so that no water falls except in the down-pourin — ud-bursts are most apt to occur on mountain icles tornado, heavily loaded with accumulated rain-water, on a. pro aching a mountain side is very much interfered with by it. 46 W. Ferrel—Cyclones, Tornadoes and Waterspouts. The draught of the ascending current, as we have seen, is mostly near the earth’s surface. en the base of the gyrat- ing column of air strikes the mountain side, this draught is somewhat cut off, and the whole system somewhat broken up, and the power of the tornado destroyed. Hence the whole accumulation of water is sometimes poured down, almost at once, on the side of the mountain, tearing up rocks and trees, and causing a great ravine. 5 Hail-storms.—As in tornadoes, there is a stratum of air ~ a ean fall to the earth, and as they may fall very slowly and 1 become suddenly weakened, or the whole system broken up, all this hail would fall rapidly to the earth, and hence the almost incredible amounts of hail] which are said to fall some- times in a very short space of time. A considerable amount of rain may be carried some distance up into the snow region before it has time to freeze. By the mixture of rain and snow, small balls of very moist snow are formed, which, being carried out where the strength of the ascending current permits them to fall slowly, they continue to grow until they become heavily coated with solid ice, and finally reach the earth. It is in this way that the large hail- stones with a snowy kernel within are formed. But these in falling are sometimes carried by the indrawing current below ER ee eg Oe ES HO TN ET, RNR gi SY Ms Oe LL Sete SER Ge ER Gere een A Se eR ag OAS Eee ANE ye ates ORE = A ee eS eee RM Bak Saree hE poet peer . : aoe aries Sie E W. Ferrel—Cyclones, Tornadoes and Waterspouts. 47 into the central part of the tornado, where the ascending currents are strong enough to carry them up again into the region of soft snow mixed with rain, where they receive the center again, to commence another similar revolution. While in the upper snow region it receives a coat of snow, and while in the region of cloud and rain, a coat of solid ice. Hence it is no unusual chines to find large hail-stones composed of a number of coatings like an onion, these coat- ings ponsieting of alternate layers of frozen soft snow and solid ice.* Sand-spouts.—These occur mostly on dry, sandy deserts where the surface becomes very much heated, and the rate of decrease of temperature with increase of altitude is such that the unsaturated and sete rope dry air is in the state of unsta- sides, in toward the acre part, and thus the nae part of the air assumes the figure of a column. As the particles of sand gyrate rapidly with the air, the centri- fugal force of the gyrations tends to driye the Lobia from the center, but this is counteracted by the resistance e indrawing currents, which is a function of the size of she’ parti- cle and the strength of their currents, since it is nearly as the square of the product of the velocity of the current into the diameter of the particle. Hence, particles of sand of different sizes arrange themselves at different distances from the center, the smaller particles penetrating nearer the center, since the centrifugal force is as the cube of the diameter, while the resist- ence of the inflowing current is nearly a s the square of the diameter. If, however, the particle were city large, it might * See American Journal of Science, I, vol. 1, p. 403. 48 W. Ferrel—Oyclones, Tornadoes and Waterspouts. wou e determined by the ascending velocity of the air at different distances from the center. feet high and perhaps about thirty or forty feet in diameter at the top. The direction of rotation was the same as of storms of the northern hemisphere. Leaving the road the whirl passed out on the prairie, immediately filling the air with hay, which was carried up in somewhat wider spirals, the diameter of the cone thus filled with hay being about one hundred and fifty feet at top. It was then observed also that the dust column was hollow. Standing nearly under it, the bottom of the dust column appeared like an annulus of dust surrounding a circular area of perfectly clear air. The area grew larger as the dust was raised higher, being about fifteen or twenty feet wide when it was last observed.” (Nature, Sept. 11th, 1879.) 0. T. Sherman—Magnetic Observations in Davis Strau. 49 Art. VIII. — Magnetic Observations made in Davis Strott, in August and September, 1880, on board the Steamship Gulnare ; by O. T. SHERMAN. THE Steamship Gulnare was provided with a Lamont mag- netometer, made by Fauth & Co., and a Kew dipping needle, made by Cassella. Before the starting of the expedition, both instruments were set up in the private observatory of Mr. C. A.’ Schott, in Washington, and the observers had the great bene- fit of his advice. The methods of observation, the forms of record and reduction are recorded, in part, in Appendix No. 16, Coast Survey Report, 1875, in part in the ‘ Admiralty Manual of Scientific Inquiry.” Frequently, however, it was found desirable to have recourse to the sextant to obtain the azimuth. The first observations we record were taken at St. John, a value 31° 30%. The variation chart, for 1880, published by the British Admiralty, shows the line of 31° ranning through the harbor. Our own value is 30° 40’. It is derived from five observations, four of which are absolutely independent. The extreme values differ among themselves by 6’-1 when reduced to the mean of 24 hours. This discrepancy I am at a loss to explain. No data are known which would refer it to local “canny The horizontal force observed was 3°3378, the dip ° 45’: Lively, Disco Island, Greenland, formed our second station. This place had formerly been visited by Sontag in Sept., 1861, who band the dip 81° 51’ and the horizontal force 1°762, but who records no declination. It was again visited by the Alert and Discovery in 1875; the record then made the declination 67° 12’-8-68° 45’, dip 81° 56’-81° 43’°7 and _ horizontal force 1770-1'805. Total force, 12°514-12°578. The remark is added that the observations showed evidence of considerable local at- traction. Our record is one of disturbance only. On August llth, the declination observed by the magnetometer varied from N, 46° 97 W., at 11" 13" a. M., to N. 49° 15/3 W., at 4* 32" Pp. M. On August 18th, at the same spot, but with an -4Zimuth compass, the declination varied from N. 67° 54-1 W., at 7 a. M., to N. 68° 52/4 W. at 3 Pp. M. Our needle was consequently deflected over twenty degrees by the magnetic storm of August 11th. On several successive days also, it was Am. Jour. a Sertzes, Vou. XXII, No. 127.—Jury, 1881. - 50 O. T. Sherman—Magnetic Observations in Davis Strait. our custom, as the ship swung with the tide, to observe the errors of the ship’s compass by reference to a fixed and distant mark. As yet, however, we have been unable to derive from them a series of values, which makes the ship’s constants at all comparable with the same values derived elsewhere ; whether from local attraction or magnetic storm, those who can refer to continued observation must determine. On August 12th, the magnetometer gave a horizontal force of 1°9042. On August 14th, in thesame position as the declination of the 11th and 18th, 1:7559. On September Ist, at a station almost mid- ay, 18842. These values correspond in magnitude to the distances from one of the many gneiss knobs. Feeling uncer- tain, therefore, as to the extent to which the observations might be affected by local attraction, more especially as observations from stations in the Waigat corresponded but poorly with those at Disco, we determined, on our return, to endeavor to dis- sea shore. All lines form a loop in the direction of Crown Prince islands. We found no spot free from local influence. A stone was brought to me while here, which both Prof. Steen- strup and myself recognized at once as ‘Ovifak meteoric iron.” It was said to have been found in Wildfire bay. From what we now know, however, it seems more likely to have been brought by the natives from Ovifak. They keep a number of these stones on hand for purposes of trade. At Rittenbenk, lat. 69° 44’, long. 51° 2’ W., we found on August 23d, 1880, the dip to be 81° 58’-9, the total force 12 6213, and the variation N. 70° 29 W., at 11" 30” local time. The Alert gives for this station a declination of 69° 8’°5 at 640 p, M. The station is granitic and there may be local attraction. At Sakkak, lat. 70° 1’ N., long. 51° 55’ W., we found on rie 24th, the dip to be 81° 59’-6, variation N. 70° 47’°3, at 5™ local time; and on August 81st, the horizontal force’ 17904, This station is also probably affected by local attrac- tion. O. T. Sherman— Observations made in Davis Strait. 51 At Kidluset, lat. 70° 10’, long. 58° 0’, August 25th, 1880, we observed a dip Sarit’: 8, and total force 125435. These are probably not affected by local influence. he Gulnare was a wooden ship with iron frame. She had seen many years’ service in the waters of New Foundland, but during the winter before the expedition sailed, had been almost entirely rebuilt. She was swung at Hampton Roads, on June 23d, 1880. The observations discussed by the method of least squares give the value of the ship’s force to head, , to starboard, —0-7845. Three days after, the salt seck the en- gineer had allowed to collect in ‘the, boiler reached a thickness of several inches and the fire boxes collapsed. ‘These were re- placed at St. Johns and for ten days and nights the iron in that part of the ship was again subjected to peas: The a was again swung at St. Johns. The value of the ship’s force reduced, after Evans, by the least ath are force to head, —1-916, to starboard, —0:2599, to nadir, —0-4081. On August 30th, ‘the values were, force to head, al ‘46299, to star- board, —0'83918. On October 5th, the values became to head, =" 9971, to starboard, —1°4525, to nadir, —0°3907. A change I should be loath to accept were it not thrust upon me by the facts of navigation. The swing of October 5th was necessita- ted by the discrepancy between the observed and calculated courses. It was our custom at sunrise or sunset to observe the angle between the sun’s limb and the line of the ship’s keel, noting at the same time the ship’s heel and course by the dis- turbed compass. These observations served at the time to cor- rect our course. Several of these have been again employed to give us the declinations at the place of observation. The ship’s forces for the date were obtained by simple interpolation from the values above given. These connected with the soft iron coefficients give us readily the values of the semi-circular varia- tion. These, finally, we have placed in the exact expression AC+Ba/—C* A+B? A? B? sin .o = which is readily deduced from Evans’ well known formula. A,B C are here easily calculated functions of the semi- circular and quadrantal coefficients, and the ship’s apparent is f 0° E 180° E., the sign — for the remaining readings. The values obtained in this way are as follows: 2B. N W. Hour, p.m, Declination. peg 5, 1880, 62°30’ 51°45’ 8 23 N. 57° 42’ W. September 10, 6T 6! 58° 307 6 43 N. 70° 59” W. September 14, 50° 20’... 6" 2G"... 6. 3 N, 67° 29” W. 52 J. W. Mallet— Crystalline form of Sipylite. Art. [X.—On the Crystalline form of Sipylite ; by J. W. MALLer. accurately together, so that the form can be easily made out. This little specimen is a tetragonal octahedron, 1°5 centime- ter long, weighing 1°627 grm. No faces are visible save those of the octahedron (1) and faint indications at one or two places of an extemely narrow plane replacing its terminal edges. The surfaces are too dull to allow a reflecting goniometer to be used, but an application goniometer gives the angles 1 A 1 (over summit)=53° 0' (Hence O ~ 1=116° 30’) 1 A 1 (adjacent pyramidal)=100° 45’ 1A 1 (basal)=127° 0’ These measurements show a close relation to fergusonite, for whic O A 1=115° 46’ 1 A 1 (pyramidal)=100° 54’ 1 A 1 (basal)=128° 28 the latter, and this,t as well as Rammelsberg’s analysis of fergusonite, supports the view expressed in my former paper that sipylite is an ortho-niobate—R”, M’, O,—containing basic ydrogen. The sipylite crystal shows distinct cleavage parallel to 1. It is fully identified with the mineral originally examined by its ewes physical characters. e sp. gr. =4°883 at 16° C.; ormerly found, 4887 at 12°-5, and 4:892 at 17°°5. Univ. of Virginia, May 21, 1881. phosphate. But no great weight can be attached to any opinion as to yttrium compounds until the confusion at present existing in relation to the metals which have together passed under this name has been cleared up. R. P. Whitfield—Structure of Dictyophyton. 53 Art. X.— Observations on the Structure of Diclyophyton and tts affinities with certain Sponges ; by R. P. WHITFIELD. In the Chemung group of New York, and in the Waverly beds of Ohio and elsewhere, there occurs a group of fossil bodies which have been described under the name Dictyophyton, but the nature of which I think has not been properly under- stood. In the 16th Report on the State Cabinet of Natural History of New York, page 84, in the remarks preceding the generic description, they are referred to the vegetable kingdom with the opinion pupae “that they are Alge of a peculiar form and mode of growth.” A reference which I think their nature does not warrant. If one examine the figures of the various species waaay given on Plates 8 to 5A of the above cited work, it w 1 be seen that these bodies are more or less elongated tubes, otraight or curved, cylindrical or angular, nodose or annulated ; and that they have been composed of a thin film or pellicle of net- work, made up of longitudinal and horizontal threads which cross each other at right angles, thereby cutting the surface of the fossil into rectangular spaces ; often with finer peter hen between the coarser ones. W the specimens, which a casts or impressions in sandstone, are carefully examined, it i is found that these threads are not interwoven with each other like basket work, or like the fibers of cloth, nor do they ante with each other as do vegetable substances ; but one set appears to pass on the outside, and the other on the inside of the body. The threads composing the net-work vary in strength, and are in regular sets in both repeals while the entire thickness of the film or substance of the ody has been very inconsiderable. In one species, the only one in which the substance filling the space between the cast and the matrix has been observed, it appears to be not more than a twentieth of an inch in thickness, and is ochreous in eagen si This eculiar net-like structure does not seem to be that of any nown plant, nor does their nodose, annulated, Ricca O38 or often sharply longitudinally angular "form, with aera) perfect corners, indicate a vegetable structure; moreover, it is not a feature likely to be retained in a soft, yielding Repetasis body of such extreme delicacy and large size, while drifting about by the action of water, in becoming imbedded in the sand of a sea bottom, but would rather were a substance of consider- able rigidity and firmness of tex In examining the structure of Bapleietis it is found to be composed of longitudinal and horizontal bands similar to those above described, with the additional feature of sets of fibers 54 R. P. Whitfield—Structure of Dictyophyton. passing in each direction obliquely across or between the longi- tudinal and horizontal sets, but not interwoven with them; so that the longitudinal series forms external ribs extending the length of the sponge, and the horizontal series inside ribs or bands, and they appear as if cemented to each other at their crossings. The oblique threads, besides strengthening the structure, cut across the angles of the quadrangular meshes formed by the two principal sets of fibers, and give to them the appearance of circular openings, making the structure much more complicated than in Dictyophyton. The addition of oblique fibers in Huplectedia is the most noticeable difference between the two forms; but if placed horizontally and longi- tudinally-between the primary sets they would produce pre- cisely the structure seen in Dictyophyton yet we have no positive evidence of the nature of the b A substance which composed the fibers in Dictyophyton. The only cases known, so far as I am aware, of the preservation of the substance of the fossil is that mentioned above, where the space between the matrix and the cast is occupied by a ferrugi- nous body, a material which so often replaces siliceous organ- isms in a fossil state, and specimens of D. Newberryi from Rich- field, Ohio, on which there occur slight patches of a carbonaceous substance, but not sufficient to warrant the conclusion that it ever formed a part of the structure, even in the opinion of the author of the genus who supposed these organisms to have been of vegetable origin ; especially as they are associated with numerous fragments of terrestrial plants. I am therefore led to the opinion, from their firmness of texture as evinced by the also figured in the 16th Report above cited, I think would also better conform to this idea than to that of a vegetable origin, although its broad flattened bands may be something of an objection. JB rasan’ SH icy Ly a FO Sa craa ah Pa raleils l Seine ar el h e, > ee eR Ea ieee koi) es pe Bea) @. 0. Broadhead— Carboniferous Rocks of Kansas. 55 Art. XI.—The oe Rocks of Southeast Kansas ; by . BROADHEAD. AT the eastern boundary of Miami County, Kansas, we find the high lands to vary from 950 to 1050 feet above the sea, the valleys being 875 to 910. In the Neosho Valley the elevation at Neosho Falls is about 1000 feet. Up to this place and a little farther we pass over a gently sloping country. It then rises more rapidly, being 1150 feet on higher land. West of the Verdigris the country rises more rapidly and is more rugged. In Osage County coal is profitably mined, which, according to Prof. Mudge belongs to the Lower Coal-measures. The Lower Coal-measures pass southwardly along the Neosho Valley which seems to occupy a trough in these measures, but eastwardly, including Miami County, the northern half of An- derson and the county northwardly, only the upper series are exposed, Apes with similar measures in Missouri West e Verdigris River the Upper Coal-measures also extend bai soon disappear beneath the “ Permian.” The main procncuse Coal-measures of Southeast Kansas lie south of iami County. Passing from Paola southwestwardly to Green- wood County, we find only a thin coal-seam Gee soalty mined but with no profitable result. Near the line of Greenwood and Woodson Counties a seam of less than a foot thickness is some- times mined. This is the most western exposure of coal ee to the Carboniferous formation. In the western part f W ounty the lowest exposed rock is 50 feet of coarse sandstone which I have referred to the Lower Coal-measures, but only a few fragmentary remains of plants were found in it. Above this are thin limestone beds full of Pusulina uae and nearly 200 feet more of sand- stone, with other limestone beds above, containing well known Carboniferous fossils, including Fusulina oo and Cheetetes he step now is more rapid to the “ Perm _ Entering the State near the line of Cowles and Viera counties, we find ourselves upon a long dividing ridge exten me and well defined for seventy miles northwardly. his ridge is much higher than the country either east or west of it, and is known in southern Kansas as the “ Flint Hills,” on account of numerous fragments of flint lying strewn over the surface. It includes the Permian rocks of Kansas and might appropriately be termed the ‘‘ Permian Mountains.” Its elevation above the sea is 1560 feet near Greenfield, in northeast part of Cowley County 1600 feet; and the highest point near the corner of Greenwood, Elk and ‘Butler about 1700 feet. This is the 56 G. C. Broadhead— Carboniferous Rocks of Kansas. highest ground east of Arkansas and Walnut Valley. On the west side of this ridge the descent is gentle and scarcely per- ceptible, being 390 feet in 25 miles to the Arkansas Valley. On the east the descent is more abrupt, the ridge presenting Is of limestone separated by shaly slopes, and the hills descend 350 feet in four miles or 390 feet in six miles, and in some places the descent is still more abrupt. From the main ridge sharp spurs extend off from six to ten miles eastwardly. From the peculiar rough character of the eastern face of this ridge good wagon passes are often distant as much as ten miles. e approaches to this ridge from Fall River Valley is by a succession of terraces or A sgt of upper Carboniferous rocks. At Twin Falls we are on a lower terrace elevated about 1000 feet save the sea. The second terrace is reached six miles ciraeabadcorineliog | at 1160 to 1180 feet. This terrace occupies a large area of the eastern part of Greenwood County with most of Elk. "The elevation of the next terrace is about 1300 feet above the sea and it reaches to the foot hills of the Permian and the slopes above blend with the Permian. This will include altogether about 500 feet of Upper Coal-measure rocks in this part ; of Kansas which lie below the Permo-carboniferous. These beds are mainly shaly sandstones with occasional limestone beds, and as far as observed contain one coal bed of seven inches with two beds of bituminous shale, and one other coal seam of five inches thickness appears just Sanaa the Permian. ‘The Permian or Permo-carboniferous of the “ Flint Hills” include a total of about 500 feet thickness. The following section I have ne from several taken within twenty miles ixty-two feet including chert layers with ‘thin beds of shaly drab- colored limestone; the highest rocks seen in “ Flint ridges,” observe ryoxoa with Athyris subtilita, Productus costatus and Hemipronites crenistria. 2. Ninety eo Bald thin limestone layers chiefly disinte- sire 3 on ex Seven feet bel of porous chert resting on limestone. He peracuta found everywhere. A Phillipsia was also ob 4. Eighty-five feet chiefly drab shales with some thin layers of limestone and red shale near lower part. Fossils are very abundant and can be picked up in a finely preserved state, and include Fistulipora (2), Productus Nebrascensis, tas semireticulatus, 5. Five feet of bluish drab and aonietithes buff limestone containing Humicrotis Hawni, Myalina perattenuata, Aviculopec- ten occidentalis. [This bed is ‘easily recognized wherever seen.] ea UN ean eg ea igi | ue pe G. C. Broadhead—Carboniferous Rocks of Kansas. 57 6. Ten feet red and green shales. 7. Fifty-three feet beds a with some beds of limestone very good for building purpos 8. Twenty-eight feet jitecdwie abounding in Fusulina cylin- drica ; the middle layers contain blue chert full of Fusuline showing the structure very finely. 9. Twenty-eight feet of sandston 10. Four feet gray limestone conannad Productus semiretic- ulatus, Allorisma granosa, A. subcuneata, Pinna peracuta, Nau- talus segs ast bed I regard as the base of the Perm . Other fossils obtained at the several localities cuolede Allo- risma subelegans, A. Topekaensis, Macrodon —, Nautilus occiden- talis, Murchisonia — though these fossils seem at home in the ’ Permian, I have obtained them also, with scarcely an bps from known Upper Coal-measure rocks of Missouri; act most of them have been obtained from the rocks of tine City. he limestones of the Permian have been roapesige'f quarried in Kansas from the southern to the northern part of the State, and many tons sent off to the market. Some of the rock quarried is too sdft for valuable structures, but many very excellent quarries have been opened. From levels taken on corresponding beds wide apart, we find there is a regular we — of not less than 25 feet per mil o be correct we may be ane in saying me RQ w~ S 75 me o OQ cf southern Kansas. In the counties of Bale Comley, Elk and Greenwood, it is the newest rock below the Quaternary. No other rocks of later formation than the Permian are found here. The PERMIAN of Kansas rests conformably on the Coal-measures and there is no decided line of separation between the two. Certain strata can be oes together as can certain other strata of other formation The only marked diftereinns is a abies Passing a certain horizon in the ascending series, we find the rocks to be all of a drab, buff or cream color and the limestones more impure and break- - ing with a rough fracture, and when vertically jointed the angle more nearly approaches a right angle, whereas the Coal-measure limestones are generally more acutely jointed and the blocks are regular rhomboids he group of the Pecan Mow NTAINS forms an interesting study; the strata are — traced and the scenery afforded is very fine and views extensi e above is an abstract of 3 a more detailed paper. 58 EW. Hilgard—Later Tertiary of the Gulf of Mexico. Art. XII.—The Later Tertiary of the Gulf of Mexico; by K. W. Hinearp, Berkeley, Cal. With a map (Pilate ITI). In view of the late earen of the Coast Survey chart of soundings in the of Mexico, and of the observations of Dr. Eugene A. Sorith’o on the Geological Formations of Florida (this varie April, 1881), I desire to summarize briefly the acts upon ich my hypothesis of a temporary and partial isolation of NG Gulf ea the Atlantic Ocean during the later portion of the Tertiary period, is based. shall add thereto some additional facts that have since been brought to my knowledge, Radar the more remote portions of the group of deposits to which, from its most .accessible and representa- tive sepoecee at the town of Grand Gulf, on ts sara aba I have given the name of “ Grand Gulf | posits , on the entire mainland border of the Gulf of Mantes from Florida to the Rio Grande. In the portions lying near the main axis of the Sk trough, the uppermost strata of the or ae rocks show, by the constant intercalation of with common and Glauber’s 5 atte The same is true of the lower portions especially, of the overlying Grand Gulf rocks; so that throughout the regiou occupied by the latter, few well- waters obtained peices them are fit for daily use, ‘and many are strongly mineral. At their lines caf contact, the Vicksburg and Grand Gulf rocks consist aia throughout of lignito-gypseous, laminated ole Ys passing u into more sandy materials: they are not nsibly uncon pethabls in place; but while the Vicksburg rooks show at all long exposures a distinct southward dip of some three to five degrees, the position of the Grand Gulf strata can rarely be shown to be otherwise than nearly or quite horizontal on the average; although in many cases faults of subsidences have caused them to dip, sometimes quite steeply, in almost any direction. They, however, lie high on the hill- tops between the towns of Vicksburg and Grand Gulf, and disappear sg the water’s edge near the Louisiana line, under — the gravel beds of ane Stratified Drift. EF. W. Hilgard—Later Tertiary of the Gulf of Mexico. 59 ‘The latter is found directly capping, almost everywhere, the claystones and sandstones that characterize the highest part of the Grand Gulf group. Clearly, the Grand Gulf rocks alone assy clays. In these, at a certain level, there occurs a stra- tum copiously traversed by calcareous seams; and smaller altogether exceptional and local, a few square miles of black prairie (Anacoco Prairie) in western Louisiana being its only striking manifestation east of the Sabine, it seems to become almost predominant in middle and southern Texas. The black calcareous prairies of that portion of Texas lie in bands sensibly parallel to the coast, each band differing somewhat in character from the rest, on account of its soils being more or less directly derived from the materials of the underlying formations. These are successively, counting from the coast landward: the Port Hudson (Champlain), Grand Gulf, Vicksburg, Jackson (Ter- tiary), and finally the Upper Cretaceous beds. is state o facts, my knowledge of which was until lately based only on scattered data gathered here and there, has received detailed confirmation from the observations made by Dr. R. H. Lough- ridge in 1879, on a reconnoissance of the State made in con- nection with the agricultural investigations of the Census. It is thus placed beyond doubt that the Grand Gulf rocks form a continuous belt, from the Perdido River on the western 60 E. W. Milgard—Later Tertiary of the Gulf of Mexico. line of Florida (where according to Dr. Smith the Vicksburg rocks reach the coast) to the Rio Grande; attaining a width of a little over a hundred miles in the axis of the Mississippi trough, southward of Vicksburg, and thence narrowing rapidly to an average width of forty miles in Texas, and crossing the Rio Grande with an approximate width of 150 miles. What becomes of it beyond the latter line, is a matter of conjecture. Of the sweep of about 900 miles thus outlined as the known extent of this formation, about 400 may be considered as hav- ing been examined sufficiently in detail to prove the absence of marine fossils from the formation; the portion so examined embracing, moreover, its widest part and fully two-thirds of the area of outcrop. I have heretofore (this Journal, Dec., 1871) remarked that such: absolute dearth of fossils in a formation whose materials are so well adapted to their preservation, staggers belief; and that I interpret the calcareous seams and concretions, found in some portions of the formation, as derived from the long-con- tinued maceration of an apparently copious fauna; as 1s exemplified in the Quaternary beds of Céte Blanche on the Louisiana coast, and notoriously in the limestones of the coral reefs. But even upon this basis two points confront us in the dis- cussion of the relations of the formation to the sea: the great rarity of the calcareous feature in the main body of the forma- tion; and the utterly “ unmarine” character of the materials generally, in the constant recurrence of the lignito-gypseous facies. The first objection disappears, as just stated, in the south ‘exan portion of the area. Curiously enough, precisely the deposits, with fossils macerated to unrecognizability. ‘To complement this statement of facts, while unable to find | q 7 pees oi i = . Se Hed ire Ass Seis Satie ie tae Gb een ge TEN ATS Os on A Re eR eS sr ate es Shae te tne SINS ae pe E.. W. Eilgard—Later Tertiary of the Gulf of Mexico. 61 any definite data to show the geological features of the region beyond the Rio Grande, I call attention to the fact that the edge of the Mexican plateau approaches the coast most closely to landward of Vera Cruz. At that place, the castle of San Juan De Ulloa stands on a rock which, from specimens brought home by soldiers from the Mexican war, I then understood to be a freshwater limestone, full of helices, or shells resembling them. If there be any more definite data extant on this point, I should be glad to have them pointed out. It seems almost incredible that so obvious a feature of a seaport so frequently visited by Americans should not have been better observed, even accidentally. The casual statements made as to the nature of the rocks by travelers, are too indefinite to afford any clue upon which con- clusions might safely be based. As to Cuba and the rest of the Antilles, we do know that their shores are lined with marine fossiliferous Tertiaries, much disturbed by the upheavals that have occurred. We even have descriptions, and quite a long list Of names, of fossils found in these formations. But on the one hand, the English the other Tertiaries of the Gulf border. Moreover, the ten- dency of most observers to pass lightly over the unconform- able, difficult deposits of the Quaternary, in which no glo can be gained by describing and naming new species, has left us with but a faint idea even as to the presence or absence of such beds on the Antilles. I shall therefore not attempt the Uunpromising task of a discussion and comparison of what is hown of their geology, with the known facts on the main- land of the United States. How are the latter to be reconciled with the now well-ascer- tained great depth of the Yucatan Channel, and the at least hot inconsiderable depth of the Straits of Florida? It seems scarcely possible to assume that both of these have been formed de novo at the end of the Tertiary period; nor even that the depth of the Yucatan Channel could have been so materially less since the Eocene time, as to allow of the freshening of “Sigsbee Deep” by the influx, whether of the regular drainage of the Continent, or of the contents of the receding great lakes of the plains. But the matter assumes 62 E. W. Hilgard—Later Tertiary of the Gulf of Mexico. a different aspect when viewed by the light now afforded by our knowledge of the configuration of the bottom of the Gulf, and of the oscillations of level to which at least its northern shore, and especially the central portion of the Mississippi Valley, have been subject in Tertiary and Quaternary times. I cannot but express my regret that the latter portion of these data should thus far rest almost alone upon my personal observations and conclusions. It seems to me that as the only portant additional data. he state of the evidence regarding these oscillations may be thus summarized: A comparatively rapid upward movement of the bottom of the Mississippi trough during early Tertiary time, is conclusively shown by the rapid decrease of the depth of the Mississippi embayment, which from its head near Cairo to about the mouth of the Arkansas, is filled with lignitiferous clays with only here and there a small marine estuarian deposit ; except that in the State of Arkansas, a residuary basin of the old (Cretaceous) trough retained deep-sea features until the beginning of the “Jackson” epoch. The latter, with its abundant marine fauna, headed by the great Zeuglodon, was evidently deposited on a comparatively steep slope forming the southern edge of the plateau that existed in the upper por- tion of the embayment; yet it also consists, in the main, of Louisiana speaks of a short duration of the epoch, at t of which the lignito-gypseous feature again appears. ee ee : a Se Ae eee TET gck Oe ME Patra peace Rafe Se Me ee ee ae E. W. ifilgard— Later Tertiary of the Gulf of Mexico. 68 About that time, as E. A. Smith’s late observations show, the Peninsula of Florida emerged from the water, apparently in the prolongation of the upheaval which traverses the State of Georgia from Atlanta to its southeast corner, forming the great “divide” between the rivers flowing directly to the Atlantic, and those tributary to the Gulf This axis of up- heaval m informed b r. Loughridge, is marked by numerous and very long trap dykes, running parallel to it in ‘ the metamorphic region of the State. As Dr. Smith has ob- served, there is a distinct ridge or ‘“‘back-bone” of Florida, formed of the Orbitoides limestone, that does not lose itself entirely until the Everglades are reached. On the Florida shore, the Vicksburg rock is mostly covered to a greater or less depth by the Quaternary coralline rock, though outcropping at Tampa and a few other points. Subsequent to this upheaval, the Miocene and Pliocene beds were deposited on the Atlantic side of the peninsula, as they were on the rest of the Atlantic coast. Meanwhile, what happened on the Gulf side? As we have seen, the Grand Gulf beds were being deposited during that time, or a part thereof, in the axis of the Mississippi trough, and all around the Texas shore to the Rio Grande, and doubtless beyond. Toward the east, these beds “run out” on or about the Perdido River, on the line between Alabama and Florida. A glance at the map of the Gulf soundings will show that this places the western line of the outcrop of the Vicksburg rocks exactly in the prolongation of the edge of the great submarine border plateau outlined by the ‘“ 100-fathom line,” from which there is such a sudden descent, all around the Gulf, Into deep water. It may be premature to infer from this coincidence, that if great shelf furnishes, as it seems to me, an explanation of the “Grand Gulf” rocks on the mainlan Mississippi Valley are proven to have been greater than on either side of the same; in other words, that it is, and has en, an axis of weakness and disturbance. As to the extent of its vertical movements in later Tertiary and Quaternary times, I have elsewhere shown that it cannot have been less than 900 feet between the time at which the great drift floods carried the northern pebbles to the Gulf shore, and that at which the loess of the Mississippi Valley was deposited. For we find the drift pebbles at a depth of 450 feet below the 64 EF. W. Ailgard—Later Tertiary of the Gulf of Mexico. waters of the Gulf, in the deep wells of Calcasieu; and the loess lies at a similar height above the sea-level, not many miles above the head of the Mississippi Delta. _ The inference is irresistible, that the upward movement of the Tertiary period continued up to the end of the Glacial poch, whose gravel could not be carried far beyond the shores of the Gulf. It is clear, also, that even a minimum elevation of 450 feet, so far proven, would convert the Gulf border, to the edge of the 100-fathom line, into a region of shallows, 900 feet above the sea, and in the reverse movement, of the Champlain epoch, they were again covered by the loess and surface loams, to be re-elevated during the “Terrace” period of erosion, by which the present channel of the Mississippi River was formed. The map of soundings exhibits very strikingly the analogy er tee, oa eae AMER. JOUR. SCI. VOL. XXT 100° 95° 90° 85° d 80° 30° rg oh MAP ILLUSTRATING A 20 r é : eee fiers PAPER ON THE } Mexico f 6 Campeche f Z ‘ ¥ | sae : //// TERTIARY OF THE GULF OF MEXICO | weet | . : / ; ee j E.W. HILGARD 100° = —— | \ a5 oi a | L are ae Ss ee J. L. Campbell—Dufrenite from Rockbridge County, Va. 65 of the relation of the two ety wale of Florida and Yucatan to the Gulf Stream on the one hand, and the basin of the Gulf on the other. The eastern akon of “boat fall off steeply into eep water, while the gulfward shores are bordered by the shelf, 100 to 130 miles in width, which breaks off into deep water at Aye 100-fathom line. It would thus seem a priori probable, that both peninsulas were elevated at the same time to a somewhat similar extent as regards their lowlands; and if so, this event cannot but have exerted a considerable influence upon the climate of the regions concerned, as well as upon the nature of the Gulf-border depo sits. Cannot something be done toward a prompt solution of this interesting problem in American Geology, upon which depend so many other mooted questions of first importance? A single season’s yachting excursion along the shores of Mexico would, under the hands of a well-posted observer, be amply sufficient to settle all the main points. Even a few specimens of rock from prominent points might go we toward the elucidation. But any such exploration should be made,-not with a view to the discovery and naming of new cious but with that of working from the base-line of the well-observed facts and in order to accomplish this end, the weary catalogue of spuri- ous species that now encumber our lists of Tertiary shells, must be thoroughly revised from the present biological point of view, is pemergy true. Nowhere would a richer field reward the labors of the faithful worker. The time for this has certainly come—but where is the man: Arr. XIIL—On iibes from pie County, Va.; by L. Camps Dvurine the summer of 1875, a number of specimens of iron ores from the Blue Ridge range in Rockbridge County, Va., were brought to my office for examination. One of these at once arrested my attention by its peculiar structure, color and luster, It had been taken from the mine in which it occurs partly in the form of irregular nodules, and partly as incrusta- tions on the surface of an underlying bed of limonite. broken open, the newly exposed surface showed a radiated, coarsely fibrous structure, with a Poit dull silky luster, and a dark greenish brown (almost black) color. Where the surfaces Am. Jour. Sct. ies Serizs, Vou. XXII, No. 127.—Juty, 1881. 66 J. L. Campbell—Dufrenite from Rockbridge County, Va. of the incrustations and nodules had been long exposed to the weather, the fibrous crystals had become changed in color to a yellowish brown, so as to resemble in general appearance fibrous limonitte—the original structure being preserved. The unaltered part of the mineral reduced to fine powder was of a light yellowish green color. en heated in a closed tube, it gave off water freely ; and small fragments, heated to redness for a short time, assumed a bright reddish chestnut- brown color when cold. Before the blowpipe, it fused readily to black magnetic beads. With the borax bead the reactions of iron were well marked, with some indications of manga- nese. The mineral dissolved readily in hot hydrochloric acid. Tests applied to the solution indicated the presence of ferric oxide in abundance, and ferrous oxide in smaller quantities ; * 4° . ° « . while reactions of phosphoric acid were very decided. A subsequent analysis of a choice specimen gave the follow- ing results: Specific gravity, 3°382 ; hardness, about 4: Phosphorie acid (as pentoxide) Seer tel POLPOUN OMI ee ke 6°144 Ferric oxide 50°845 Alumina 0°212 manwanoun UXIGB Gf oe ee ds ek 0°403 ime 17124 g c 0°762 Water lost at red heat 8°531 Insoluble silica—very fine sand.................------. 07115 99°897 ody of the mineral mass is “ dufrenite,” which hitherto seems rarely to have given identical results in the hands of any two as “South Mountain ”—one of the many primordial broken northeast of the same stream. But if the stratum on the sec- tion marked lg be conceived to extend nearly to the top of B. Silliman—Turquois of New Mexico. 67 that marked 1f its upper limit would very well Seger the geological locality of the mineral deposit. The strata here, owever, have a much more moderate dip than at the og cut by the section. rude shaft or pit was found to have been sank through the beds of dufrenite into a mass of underlying limonite to a depth of ten or twelve feet. The irregular bed of dufrenite, made up of irregular nodular masses, having from one to eight inches of diameter, and incrustations of like varying thickness, lies near the surface of the ground, and has an average dept of ten or twelve inches, as far as could be determined in the presence of a considerable caving in of the old shaft. his mineral had been thrown aside in mining as being of doubtful character, in the eyes of those who were exploring for iron ores, and several tons had been accumulated near the mouth of the opening ; but since I first called attention to its true character, and although the locality is difficult of access, the whole of what was thrown out by the miners has been car- ried away and sent to different public institutions and to deal- ers in minerals. This is, perhaps, the most extensive deposit of this mineral yet discovered in the United States Washington and Lee University, Tovthaten: Va., May, 1881. Art. XIV.—Turquois of New Mexico; by B. StnLiMAn.* THE existence of turquois, a comparatively rare gem, 1 New Mexico, is a fact long known. The chief locality is py Mt. Chalchuitl, in Los Cerillos, about twenty-two miles south- sta of the ancient town of Santa Fé, the wae: of that terri- tory. We are indebted to Professor Wm. P. Blake for our first detailed notice of this ancient mine, in an article published in the American Journal of Sciencet in 1857. It was subsequently visited by Dr. Newberry who mentioned it in one of his reports, and also by others. I have lately had an opportunity of examining this very interesting Jooaliay since it has been laid open in the old workings and thus rendered accessible to observation by the recent explorations of Mr. D O. Hyde. The Cerillos Mountains have recently come into notice ions the partial, and as yet superficial, exploration of very numer- ous ee veins which are found to intersect them, and which ad before the American Association for the Advancement of Science, iene oni 1880. + This Jou ronal, 2d Ser., xxv, 27. 68 B. Sitliman—Turquors of New Mexico. earry chiefly argentiferous galena, with some gray copper rich in silver, giving promise of mines of value when opened in depth. I have elsewhere spoken more particularly of these veins and of the rocks that contain them. ese rocks are all eruptive rocks of the family of the augite trachytes, the kind which, the world over, carries the richest and most permanent ores of silver, with some gold. In the center of this district, which is not more than about six miles by four in extent, rises the dome of Mt. Chalchuitl (whose name the old Mexi- -In the other direction this mountain has its drainage into the valley of the Galisteo, which forms the southern boundary of the Cerillos district. The age of eruption of these volcanic rocks is probably Tertiary. The rocks which form Mt. Chal- chuit] are at once distinguished from those of the surround- ing and associated ranges of the Cerillos by their white color and decomposed appearance, closely resembling tuff and kaolin, and giving evidence to the observer familiar with such phe- nomena of extensive and profound alteration; due, probably, to the escape through them, at this point, of heated vapor of water and perhaps of other vapors or gases, by the action of which the original crystalline structure of the mass has been completely decomposed or metamorphosed, with the production of new chemical compounds. Among these the turquois is the most conspicuous and important. In this yellowish-white and kaolin-like tufaceous rock the turquois is found in thin veinlets and little balls or concretions called “ nuggets,” covered with a crust of the nearly white tuft, which within consist generally, as seen on a cross fracture, of the less valued varieties of this gem. = The observer is deeply impressed on inspecting this locality with the enormous amount of labor which in ancient times has been expended here. The waste or debris excavated in the i h acres. On the slopes and sides of the great piles of rubbish are growing large cedars and pines, the age of which—judging from their size and slowness of growth in this very dry regioD (eter ae Seana Se ee wb aac OF ini tag atc ea ae a ae — a epe t es BY SEA eee te sah 2 eee Popo Sea Bere ae Sara Sue ag ing Re a PERE re Rees se B. Silliman—Turquois of New Mexico. 69 —must be reckoned by centuries. It is well known that in 1680 a large section of the mountain suddenly fell in from ‘the undermining of the mass by the Indian miners, killing a con- siderable number, and that this accident was the immediate cause of the uprising of the Pueblos and the expulsion of the Spaniards in that year, just’ two centuries since. .& piss Turqvois MInEs, yy Yr eae Wy Yyt Mt. Chalchuitl, Yyy 0p Yyy Uy 2 Yj Uf : idan iad Gp Yyfyy g Yyyyy Hy Longitudinal Section. YY ty uy tf { of Wy SS YY; WSS SX Orkin: See in Shaft No. 2 SS ~ x ) YY YY Zo YY Ys ae rap HY UG Wy Ly, | Yyy YY YY Y YY, irlfryy t Yfyyy, iffy OY Yt rrp UWI IJ) f/f 435,4{ YI YY YYIPI|-_/ JJ Ww yy “iy 4 Vide bey lf Ship thy Sly ; sm Yy Z : ti Ye Mp Yj UY YLT. YW MIYY The accompanying vertical section of the mountain from swung as sledges, fashioned with wedge-shaped edges and a groove for a handle. A hammer weighing over twenty pounds was found while I was at the Cerillos, to which the wyth was still attached, with its oak handle—the same scrub oak which is found growing abundantly on the hillsides—now quite well perserved after at least two centuries of entombment in this perfectly dry rock. 70 B. Silliman—Turquois of New Mexico. The stone used for these hammers is the hard and tough hornblende andesite, or propylite, which forms the Cerro d’Oro and other Cerillos hills) With these rude .tools and without iron and steel, using fire in place of pice oti these patient old workers managed to break down and remove the incredible masses of chess baceas rocks hice form. the mounds already describe That considerable quantities of the turquois were obtained can hardly be questioned. We know that the ancient Mexicans attached great value to this ornamental stone, as the Indians do to this day. The familiar tale of the gift of large and costly turquois by Montezuma to Cortez for the Spanish crown, as narrated by Clavigero in his history of Mexico, is evidence of this high estimation. It is not known that any other locality in America has furnished turquois in any quantity—the only other place thus far reported outside of Los Cerillos meine that near Columbus District in mht discovered by Mr. Clayton; and this is not yet wo The origin of the turquois of Los Cerillos in view of late observations is not doubtful. Chemically it is a hydrous aluminum phosphate. Its blue color is due to a variable uantity of copper oxide derived from associated rocks. I find that the Cerillos turquois contains 3°81 per cent of this metal. Neglecting this constituent, the formula for turquois requires : Phosphoric acid 32°6, alumina 47 ‘0, water 205=100°?. Evidently the decomposition of the feldspar of the trachyte furnishes the alumina, while the apatite, or phosphate of lime, rock, furnished the phosphoric acid, A little copper ore is diffused as a constituent of the veins of this region, and hence the color which that metal imparts. crystalline rocks of the district ipa the line of volcanic fis- ures. In fact there are, in a northerly direction, other places, Chemistry and Physics. 71 one of them at Bonanza City, probably two or three miles distant, where the same evidence of decomposition is found, and in the rocks at this place I found also the turquois in forms not to be distinguished from those of the old mine. Mr. Hyde has shown me lately in New York a large number of the Cerillos turquois polished, one of huge size; and among them a few of good color and worthy of consideration as gems, some of them an inch in length and quite thick, but they are not of faultless beauty. SCIEN TIF IC INTELEAGLACE. I. CHEMISTRY AND PHYSICS. n Free Fluorine in Fluor Spar.—The cause of the peculiar odor possess by the dark violet fluor spar of Wélsendorf has been much discussed. Schafhiutl ascribed it to the presence of Pe hypochlorite, Schrotter to ozone, Pepa to antozone, and Wyrouboff to a hydrocarbon. Loxrw, noticing the similarity of the odor on freshly ee surfaces to eee of chlorine, con- cluded that it was due to the presence of fluorine formed by the dissociation of some foreign Rivne present in minute quantity. The ozone theory was given up by Schrétter when he found that the odor was not destroyed by a heat of 310°. Moreover, he Levee an alteration in this odor when the mineral was ground portions at a time, the filtrate and wash-waters from the earlier being used with the later quantities. The last filtrate was mixed with sodium carbonate, evaporated, the residue treated in a platinum capsule with sulphuric acid, and PES bi en a watch glass, kept at 40° to 50° for a a long ti ining the glass it was found to be very ceuikershly Seen Since fluor spar is not entirel ee in water, the experiment was repeated, using the inodorou ral. The result was so exceedingly feeble as to dispose entirely of this objection to the ormer result. Since these dark radiated varieties of fluorite contain cerium, the author thinks a ceric fluoride is the source of Br “On Arsenobenzene.—Azo-benzene C,H,.N=NC,H,, has Jong been known, and phosphobenzene C,H H,P—Pc Ase ‘has recently been discovered. The cortehponten. pees of arsenic, arseno - 12 Scientific Intelligence. fy Pecan iodide when reduced gives arseno-iodo-benzene thalene C,,H,As=AsC_H, being produced by the reduction of 102 T remaining powder is extremely deliquescent. On analysis it gave numbers agreeing with the formula C,,H,,O, nce the first ow as a combination of this with a molecule of alcohol, C,, ,H,O, which requires 8-9 per cent of alcohol. This, and the residue dried over sulphuric acid, gives a body whose i WH,,0, hen therefore the alcohol in the above formula is replaced by water the formula be- — 19-98 4° 4, OF C,H,,0, This hydrated body pos sesses all the physical, chemical and organoleptic properties of @ dextrin. It is amorphous, yellowish, very soluble in water, of 4 Chemistry and Physics. 73 ? tase, is converted into dextrose by prolonged coin with dilute sulphuric acid, and has the diffusibility of a dextrin, being nearest to the y-dextrin of Musculus.— Bull. Soc. Ch., I, xxxv, 368, Apr., 1881. 4, On etree: Acid.—LwkEs has tet sere established the existence of pentathionic acid. Continuous currents of hydro- gen sulphide and molphajoes oxide gases were ae “according ackenroder’s method, into distilled water, the former in slight excess, for seven hours, the mass heated on a water bath, filtered from sulphur and analyzed. Three separate methods gave in 10c.¢, 0°23, 0°227 and 0°226 of sulphur. On titrition, 1 cc. neutralized 0°01457 gram K,O, equal to 0°012 gram potas- sium; thus giving 2: 4°55 for the ratio of K: S, and suggesting the presence of an acid having more sulphur than the tetrathionate. aving noticed that a partly neutralized solution decomposed only very slightly, Lewes added to a solution prepared as above a weak solution of barium hydrate, sufficient to neutralize ous half of it. On —- after — seyret Sande, hours, a clear op as obtained which proved on analysis to be barium pabares pee salt is soluble in cold wa r and if not too concentr ated the solu- tion may be oiled. The. reactions of the solution are y the same — > three potassium salts of pentat — “acid were obtaine n i-opake, prob rhombic ¢ 2,0, (H,0), ; enchant in small and apparently m odie cr ystals, having one molecule of water of crystallization; and ird in very small, short prisms, which is the anhydrous pentathionate K,S,0,. These salts may be easily prepared as they are the corresponding tetrathionates by the fact that they give an yma prec pre of sulphur op neers an alkali He ate,— 0¢., ¥XXix, 68, March, 1 G. F. B. togr aphi C8: AN eries of Lea sons, accompanied by mde: is somewhat novel. After ziving in a clear and satisfactory We: on the upper half of the page, the matter culled from his o 74 Scientific Intelligence. experience, he prints in pclae type, on the lower half, quota- tions bearing directly on the subject in hand, and taken from the est authorities known. In this way the Soo eg of over two hundred authors have been secured to the reader. The science and the art of photography is given in twenty-seven lessons, eac treating of one branch. The first of these on the treatment of technique of the wet plate process in all its parts. med dry plate process follows this, and then some of the more recent photo- type sine: and the book - age some asctak practical suggestions. The work appears to be a great success in its man- ner as well as its matter. It ai cer sainly become the standard book on photography in this country. G. F. B. 6. Conservation of Electricity.—In a memoir by M. G. Lirr- MANN, presented to the French Academy by M. Jamin, the author maintains that the quantity of matter and the quantity of energy ingnttadee in aatore Which remain le, The dist the ae nmantitg of alenteasisy wis ha a. body receives ane ids; x can e, for example, the potential which the body acquires, ¥ its capacity, or a quantity proportional to the capacity. et dm be the quantity of electricity received by a body when = is sacstaaed by ca and y by dy; one can then i dm =Pdx+Qdy, in which P and Q are two functions of # an y. The principle of the dongerentses of electricity is expr i by the condition that dm shall be an exact differential. Divide, for instance, any system in which an electrical phenomenon is produced, into two portions, | Se nd Let a and 6 be the simultaneous variations of these wo portions. In virtue of this principle of the Conservation of Electricity, we must have a+b=0, When A passes over 2 closed cycle, that is to say, when its final state corresponds to its initial one, a=0 and ’=0. We can then write /dm=0. In order that /dm may be zero for every closed cycle, it is neces sary that dm shall be an exact differental, a ae In this Y de rwe can write the analytical expressions for the general ip of Ae ee ac of Electricity.— Comptes ro 0. 18 0 lent to that of ten to fifteen Bone elements. In obtaining, therefore, a light from a battery of thirty to forty Bunsen cells, Geology and Natural History. 75 only twenty-five are useful in Roiniones the light. Thus os “ difficult to produce two or a greater number of arcs in the sa continuous curreut, since it is necessary to overcome the inverse electromotive force of each light. This fact is an objection to the use of batteries, Lave gs ous current machines, secondary batteries like those of Planté or of Faure. The conditions, however, are very different with oe use of alternate current dyna mo-electri ic ma- chines; for with a certain speed of alternation the effect of the inverse electromotive force i isa minimum. ‘The difference of tem- t e PERS apf edn, No. 18, Mae 8. Stellar Photography.—In a letter se eho to M. A. Ciena H. Draper relates that he — — xt in ide aneare? alter fo 14°1, 14-2, 14°7, according to the scale of Poyson. Photography has thus secured images of stars nearly at the ner of waibility in a telescope of nine inches aperture. It seems, therefore, not improbable that stars which are invisible to he. eye in a tele- pee of a size can be photographed.— Comptes Rendus, > 0. Pete ril, 188 ‘ Weat Ae Warnings.—Professor aga ee ed in lecture delivered at South Kensington, April 29, spoke of t probability that British magnetical weather ad be followed si ae pehe of Eleivicity. —M. Favre has modified the sectiadk pe nei of Planté by coating the lead plates with a covering miniu The sheets of lead are separately covered with pote aed rolled erethen | in a spiral with a layer of felt be- tween, and are then placed in a vessel of sulphuric acid and water. hen a current is passed into this cell the minium on one plate is reduced to metallic lead and on the other is oxidised to peroxide. When the cell is discharged this action is reversed. According to M. ian axl one of these spiral cells weighing 75 kilograms can store up energy sufficient to furnish one horse power for an bout ss Nara May 19, 1881. a8 Il. GroLtoegy AND NaruraAu Hisrory. 1. Sketch of the ge Oe —. Columbia ; by GxoraE M. Dawson, D.S., A.R.S.M., —British Columbia includes a = portion of the Saree a oe Cordillera region of the west coast of America, which may be described as consisting here of 76 Scientific Intelligence. ,four parallel mountain pes running in a northwest and south- east bearing. Of these the southwestern is represented by Van- couver and the Queen “Charlotte Islands, and may be referred to as the Vancouver Range; while the ne xt, to the northeast, is the miles in width. This is ste a by the interior _plateau ™ and ahayond this the Rocky Massena proper, forming the western margin of the great plains of the interior of the continent. Tertiary rocks, which are probably of Miocene age, are — both on the coast a over the hese platea They con- sist on the coast of marine beds, generally Hittoral in enter which are capped, in tha: Quée peDbarlotts Islands, by volcanic rocks. The interior plateau haa) been a freshwater ‘lake, i in or on the margin of which, clays and sandstones, with occasional lig- nites, have been laid down. These are covered with very exten- sive volcanic accumulations, basaltic or tufaceous retaceous rocks from the age of the Upper a Lower Chalk to the Upper Neocomian, and representing the Chico and Shasta roups of California, occur on Vancouver and the Queen Charlotte sland i a older beds of the Queen Charlotte Islands, Within the Coast range the sii He vk are probably for the most part eat alent in age tot pper Neocomian. The Cretaceous rocks a of great thickness, both on the coast and inland, and include extensive contemporaneous volcanic beds. The pre earnest beds had been much disturbed and altered an extensiv is Suabhencioae by it olistls as oast Range ‘ roomie o be built up chiefly of rocks like — of Vancouver Island, but still more highly altered, and appearing as gneisses, mica- shists, &e., while a persistent a argilla- ceous and slaty zone is supposed to swe ae the Triassic argillites of the Queen Charlotte Islands. The older rocks of the interior Sager are largely composed of quartzites and limestones; but s old much contemporaneous voleanic oe together ‘with sip eciue, Car ven aie fossils have been found in the lim estones in a number of plac The Triassic is slop represented in some places by great osiees i — plat see deposits with limestones. In olden Range, te conditions found in the Coast Range are anette to be repeated ; but it is probable that there are Geology and Natural History. 77 here also extensive areas of Archean rocks. Some small areas of ancient Soiree rocks, supposed to be of this age, have already been by a red. ae Mountain Range consists of oe with quartz- ites tea shaly beds, dolomites and red sandstones. The latter have been observed near the 49th parallel, res are supposed to be Triassic in age. e limestones are, for t ost part, Carbon- iferous and Devonian, and no fossils have a been discovered indicating a greater age than the last-named period. On the 49th parallel, however, the series is supposed to extend down to the Cambrian, and compares closely with the sections of the region east of the Wahsat tch, on the 40th parallel, given by Clarence King. Volcanic material is still present in the Carboniferous rocks on the 49th paralle The oldest land is that of — eae a and th aiser, widen deposits laid down east and west of this barrier differ widely in character. The Carboniferous ‘elosad with a dis- turbance en dies shut the sea out from a great area east of the Gold Range, in which the red akan and saline beds of the Jura-trias were formed. In the Peace River region, however, marine Triassic beds are found on gee sides of the Rocky Moun- tains. A great disturbance, producing the Sierra Nevada and Van- couver ranges, closed the Triassic and Jurassic period. The shore line of the Pacific of the vacbexeaiunsy in British Columbia lay east of the Coast Range, and the communicated by the Peace satel region with the parte Mediterranean of the great plains. 0 ene deposits have been found in the province. The Miocene of the interior plateau is probably homologous with King’s Pah-Ute lake of the 40th parallel Miocene. In the Pliocene the country appears to have stood higher above the sea-level than at present, and pape — time the fiords of the coast were probably worn out.—Proe. i. Soe. London, 1881. - 2. Caribbean Miocene “oosile —A memoir, on Miocene fossils Dom 3. Report of the "State Geologist of New Jersey for the year 1880.—Professor GrorcE H. Cook, the State Geologist, dcvoesd a considerable part of his last report to a discussion of the relations of the soils of the various regions of the State to the accompany- ing rocks, which subject was illustrated by a colored map of the State. The Report for 1880 contains an extended account of the Glacial drift over New Jersey, apa, the facts as to the course of the terminal moraine across the State, terraces along valleys, and those as to other gravel and ah deposits, chiefly in South- ern New J ersey, which are regarded as of pre-glacial origin. 78 Scientific Intelligence. « He then shows that on the Passaic River, southwest of Patterson, the waters of the flooded river were spread into a lake 30 by 6 or 8 miles in its diameters and 200 feet deep, owing to the confining ridges of trap on the east and south. ne of the most remark- markings. The largest, in North Dennisville, measured 14 feet in length and averaged 11 by 17 inches in its other dimensions ; another is 7 feet in diameter. It is suggested that they may have come on floating ice down the Delaware when the waters stood “5 feet above their present level. t Paterson a well has been sunk 2100 feet in the Red Sand- stone (Triassic), proving = that the thickness of the rock ex- ceeds this amount. It obtained water at 1120 and 2050 feet; and that at the latter depth (which ascended to within 30 feet of the surface) was saline, ae containing about half as much common salt as the water of the ocean, abe more of comer yay of potassium, calcium and magnesia. The total amount of solid matter per or swam of this Shek pte in 1883, re ae eos its com- mencement, the whole expense having been $445,000, besides the rinting The ‘Geology of the Oil Regions of Warren, Venango, Clarion and Butler Counties; by Joun F. Cartr, Report t LIL of the Geological Survey of. Pennsylvania. 482 pp., 8vo.—Mr. Carll’s report shows careful and judicious observation in all its chapters, whether treating of geology or the characteristics of the oil-pro- ducing regions; the condition of the oil deposits, the origin of an account of oil-well exploration, machinery and tools. In these and all its subjects, it is well illustrated by drawings and sections. It is a work of great practical and scientific value 5. Annual Report of the Bureau of Statistics esd Geology of Indiana for 1880.—In Indiana, the duties of State Geologist were, geologist, is the Chief. It is creditable to the intelligence of that State, that their law requires that the head of that Bureau shall be an expert in the sciences of geology ray chemistry. Professor Collett has pub- lished two annual reports, the last of which contains about fifty pages on geology with plates of fossils. J. 6. Lllustrations of the Earth’s Surface: Glaciers; by N. Suater, Professor of Paleontology, and Wm. M. Davis, Instrue- . a] Geology and Natural History. 79 i in Geology, in Harvard sei el 196 pp., large 4to, withe lates. Boston, 1881. (James R. Osgood & Co.)— —The plan of ei series of which this volume is 2s fin st is to nat illustra- tions of prominent subjects in geology—Glaciers, Mountains, Volcanoes, Earthquakes, etc., as far as possible from pho tographs, and accompanying text iving “a connected i of the more bisa Knots and theories that belong to each cation ” 'The vol- me w has been issued, on Glaciers, is exceedingly well adapted for its murpose. Its illustrations desgies nt some of the most char- 4to‘size, that exhibits all details in perfection. Among them are’ the Glacier des Bossons, de Taléfre from the Jardin, the Aletsch in several views, du Géant, and others, in the Alps, with some from the Himalaya, Norway, ete. Be sides these, several plates are devoted to other Glacial phenomena, and some to those of the Glacial era, fie donc the American. The subjects are happily chosen for instructiveness, and the beauty of the plates is remark- able. ait xt gives an excellent general review of the subject of Rene ay modern and ancient, with many important descriptive details. It discusses Croll’s theory of the origin of glacial cold, with criticisms, and also other se on the Subject ; treats of mentioned beyo nd. The volume is’a very valuable one tee both instructor and student. 7. The Trilobite New and Old — Relating to its eew: ization; by C. D. Waxcorr. Bull. p-. Zool., vol. viii, No. 1 —Mr, Walcott here presents the oe of his semarkable cpa tions of Trilobites, with full — on six plates. The species examined were Ceraurus pleurexanthemus, Calymene senaria, and Asaphus patyeephadsa The results show, beyond a ii the existence of a series of jointed organs about the organs, looking as if spiral, and supposed by the author to be branchial in — A “restoration” of Calymene senaria is given on plate vi. The series of legs in this “argos looks very aeabeea, for, if so distinct in the animal, it seems to be incomprehensible that such dissections should have ie needed for their discovery. A series of distinct ambulatory legs on a ha Trilobite should have been large and stout, and could thorax and pees extrem mity, W which have the appearance of aving been thin or membranous, are merely subdivided and thickened portions of the outer ventral shell, which served as attachments for thin membranous articulated appe: anaes such as have meohente been attributed to Trilobites. nD 80 Scientific Intelligence. 8. Geological Survey of Alabama: Report of progress for 1879 and 1880; by Everne A. Smirn, Ph.D., State Geologist ; 5 ., 8vo.—This report contains a detailed description of the coal-measures of the Warrior Coal Field, and is accompanied by a geological map of the region. . The Felsites and their associated rocks north of Boston; by J. 8. Duter. Bulletin of the Museum of Comparative Zoology at Harvard College, vol. vii, (Geological Series, vol. i, pp. 165 to 180, 8vo).—Prof. Diller treats of the physical and other char- acters of the felsitic rocks, including felsites.and conglomerates, of Medford, Malden, Melrose, Wakefield, Saugus and Lynn, in Eastern Massachusetts, and of some of the adjoining rocks. ‘ He arrives at the conclusion that the felsites are eruptive rocks. He gives for the order of age for the rocks referred to as erup- ive: granite, felsyte, dioryte, and diabase and melaphyre. 10. Mémoire sur les Phénoménes d’ Altération des Dépots super- ficiels par Vinfiltration des eaux Météoriques, étudiés dans leurs rapports avee la Géologie stratigraphique, par Ernest VAN DEN Rc@ecK, Conservateur au Musée Royale d’Histoire Naturelle, At- taché au service de la Carte Géologique. 180 pp. 4to, with a folded plate. Bruxelles, 1881. From vol. xlivy of Mém, Couron- disturbance. In other cases gray beds are overlaid by yellow beds or gray clays by yellow clay deposits; and as before, the of Quaternary deposits, fully sustaining his conclusions. : 11. On the application of a solution of mercuric potassium GoLpscHMIDt. ingenious meth r separating mechan- ically the mineral constituents of a rock, propose . Thoulet, has already been extensively employed by lithologists. | This suric 1 Geology and Natural History. 81 high specific gravity ; and further that, by the addition of dis- tilled water drop by drop, any required density, trom thee maxi- mum (Thoulet) 2°77, down to 1, may be obtained. If now the fine fragments of a rock be introduced into the solution, Slee. ice density is tem or less than that of the solution will float and all others will sink. By carrying on the process in a suitable vener and by yada, as circumstances require, the density of the m struum, the separation of several different minerals may be accom- lished. For the further discussion of the subj ect, as given b f. Thoulet, reference must be made to his valuable memoir on a Contributions a Pétude des propriétés physiques et Fag c. Min. France, ii, 17, 1881). This method has been exhaustively studicl by Golds chmidt, and the results given in his memoir w how much can be accomplished in this way that was aes ty any of the earlier methods of mechanical separation ; at the same time he calls attention to the conditions ss which success de- pends and to the various opportunities of error. The maximum density. obtained by him was 37196 but v veriog somewhat with the temperature. By the use of the solution Goldschmidt shows that with due care the specific gravity of a pure mineral in fragments can be obtained with an error of only 2 or 3 units in the fourth place of decimals. He determines in this way the specific gravity differ of a large series of specimens of ent kinds of feldspar and concludes that the method gives a sure means of separating the different species of the group when In regard to obtained by him in a number of 1 epital. ‘idee te haa’ also been —Mr. J. H. Cou describes, in the Transactions of the Royal Geological Society of Cornw wall, deer-horns, now in the British Museum, that were In some parts, gi : trved or reproduced in oxide of tin” and even contain in places » ata “Sei cm of this oxide. They are reported as havi en oe ‘aff rded bim on mm analysie 2°60 per hte of stannic ek ese introduced ingredients is small, ‘they were found, hes ineroseopie Am. Jour. Scr. Daim, Sanam, Vs XXII, No. 127.—Joxy, 82 Scientific Intelligence. examination, to be distributed in the interior Of each cell through the mass. Mr. Collins supposes that the tin was introduced by means of the fluoride. 13. Microlite from Amelia County, Virginia.—The rare species microlite, hitherto known only in minute crystals from Chester- field, Mass., Branchville, _ Uti, Sweden, has been ee of. W. M. Fo characters are: H.=6 or a goich e8s ; & 5 "656; luster fh dee resinous; color, wax ye ellow o brown; stre k, pale ochreous yel- low; sub-translucent; pie colebokiat: very brittle. An analy- sis gay oe he Cb,0; WO; Sn0, CaO MgO BeO U.0s Y203 68°43 174 0°30 E06, 21:30. VOL. 034 1°59 0°23 Ce.Os, Di.O; Al.Os Fe,03 Na,O K,O F H,0, deduct 0°13 0°29 2°86 0°29 2°85 1.17 O17 O replaced by F r 05 This shows the mineral to be essentially a calcium pyrotanta- late, The formula deduced is— } (ni Wo,) TObOF,. eg Chem. bekig ili, 130, May, 1881. Mya arenari aay paper in the American Naturalist for way last , by R. E. C. Stearns, ri a that this mollusk, the “long clam” of eastern waters, has recently become the “ leading clam” in the markets of San Francisco sah Oakland, although unknown on the coast until the discovery of a few specimens on the eastern side of ae bay in 1874. How introduced is yet an unan- swered questio “ 15. Eentoopods. the food of some young Fishes.—Dr. Leidy reports that the young of some of the su ys ED oaeticar gy ¥ b ki III. Astronomy. 1. On the Figures of the Planets.—The conclusions. of f Pro- fessor Hennessy in PPh orb to the form of the planet Mars have n given on p. 162 of the last volume of this Journal (Feb. 1881). Ina sf eet in the Comptes Rendus (1881, p. 225) Astronomy. 83 he gives the formulas stipe by him for the pompression (e) of a planet resulting from superficial abrasion, and shows that this would be ree less than that resulting from the ‘gucci of primitive fluidity. The ee gerbe of the formule to the planets whose times of estios an n density are most similar to the earth give the following resu or the planet Mercury, if we 6 kami 86700” for its time of rota- tion, ‘075 for the ratio of its mass to that of the earth, and °378 | for the ratio of its diameter to the earth’s mean diameter, we find Q= ae a3 and if the planet were homogeneous, Hee ~ 325 With the same law of density as in the earth, on the fluid theory, 1 | Om ai8? and on the theory of abrasion, e= 586° These three results na that for Mercury no sensible compres- sion is likely to be e or Venus, if we pepe the values of the mass M, time of rota- tion T, and diameter a, generally admitted, namely 1 M=——_., T= 23" 21™ 22° = "954 M = 779150" ajute Hoan toe I find for the compression, on bec ee of fluidity and a law of density like that for the ea ae Yc and by the hypothesis of abrasion at surface, oe é= 351° The first of these values approaches closely to the compression recently observed by Colonel Tennant—namely, e==—. So far, peed the figure of Venus is more consistent with the theory of fluidit ty than with the theory of as pte abrasion. Sines communicated my note on Mars to the Academy, I have become acquainted witht the new ty Sekaristbacin of the planet’s mass obtained from the motions of its satellites. The astronomers of the Washington Observatory have ata especial attention to the satellites of this planet. Professor Asaph Hall has pub- lished results* which lead to the Sscalanicn that the mass of Mars is probably about 3093500" ‘ With this value, and the values of other elements remaining * Washington Astronomical Observations, xxii, Appendix. 8 Astronomy. : r : nearl 203-74 © 204 y- the same as in my previous note, Q becomes On : ; 1 1 The compression on the fluid theory becomes s0ee oa07 1 : the theory of abrasion the compression is —-~ deg The first is much - nearer to the observed sega — Aare the last. April, 1 " Giscrsattens of the Transit of Venus, Dec. 8-9, 1874. Part I. Washington: Government Printing Office. 1880. Edi- ted by Smmon Newcoms.—This is the first of four proposed parts in which the Observations made and-reduced under the direction of the Commission created by Congress are to be published. The remaining parts will give the observations in detail, the discussion of the longitudes of the stations and the measures of the photo- t pa es the general account of the operations and the reduction i results of the gbeets shone and oo might have been the last esta of the first part. The iactasoe of the errors and discrepancies among the pho- tographic results, and the determination of a value of the solar arallax are not given, as the Astronomische Gesellschaft has discouraged the publication of separate results for the solar par- allax until the whole of the Beats of all parties can be com- bined in a single discussion. The remark is made, however, that the probable error of the photographic siedbishenaents far exceeds what was ego) estimat The fourth chapter nay a treatment of the contact observa- tions, of which twenty-five were secured. These, also, are reduced to the form of observation equations, very like those from the photographs. The leasons which these results furnish with ape to the observations of the transit in 1882 are not'deve eloped, it seems probable that the photographic methods must be Suprived, or else i. HAM 3. Observations of Double Stars made at the U. 8. Naval Observatory ; by Asapn Haxrt.—Professor Hall has given in Miscellaneous Intelligence. 85 this memoir the results of his observations on double stars with the sae inch equatorial of the Naval Observatory, made during the five years, 1875-9, together with a few measures made in 1863, with the 9.6 equatorial. A group of observations is first given on selected stars, made in concert wit r. Struve and Baron Dembowski, for the e pur- pose of eliminating constant errors of ponies angle ‘if possible. A series of measures upon two triple stars and upon the trape- zium of Orion, give further means of estimating the accuracy of Professor Hall’s measures with the great equatorial. The main part of the memoir is devoted to the measures of other double stars. The total number of observations is 1,614 on over 400 different stars. When we consider that one good observation of a dou ea star is ‘orth scores of those of moderate or doubtful value, appreciate more highly the value of such a series of bbaseratione i such an observer. Bsa. IV. MisceLLangous Screntiric INTELLIGENCE. 1. Historical Sketch of the Boston Society of Natural History, the Anniversary Memoirs of the ton Soci f Natural History, published in celebration of the Fiftieth apegient! of the Society’s foundation.—This volume een mportant n 1830, it acquired faves of what remained ‘of the collec. tone of the Linnean iety, but ‘nothing of any se one pe value was obtained.’ The & society was without endowment, and the income for the first year from the fees of sister and a course of lectures, after deducting the expenses of the lectures, was but little over ‘five hundred dollars. Through the liberality Proceedings. Considering the expenses of publication, of the care of specimens, the great importance of extending the collec- tions, and the required outlays for curators, librarian, and other urgent needs, the amount is still small; and i t that it is so much is an honor to the generous citizens of Boston, who are sure to keep making it ag oe Mr. Bouvé, in his eeollent history of the pee gives the details of the society’s progress and a general ount of the work it has accomplished. The volume contains, aan, brief, life-like get of the members that have died, among whom are a er oe will be long remembered in science—Dr, Benjani D. Gre Amos Binney, Dr. Burnett, . Warren, Dr. Harris, Dr. Gould, Phaslen Pickering, Agassiz, 86 Miscellaneous Intelligence. Ww sh man was president for fourteen ing (from 1856 to 1870), and, like Agassiz, was a man to be ever kept in mind for his excelfencies by future generations of laborers in science. The Boston Rociet ty of Natural History owes much to the author of this volume for the faithful and judicious manner in which it has been prepared. 2. American Association at Cincinnati.—The next meeting -of the American ——— for the Advancement of Science opens at Cincinnati on the 17th of August. Professor GEorGE J. Brusn, of New Haven, iy is President of the m eeting ; Pro- fessor A. M. Mayer of Hobo en, N. J., Vice-President of Section a and C. V. Ritey, of Washington, D. C., General Secretary. The Chairman ie the Subsection of Chemistr y is W. R. Nicnots, of oston, Mass.; of Mics roscopy, . Hervey, of Taunton, | 0 pea se J. G. Morris, of Baltimore, Md.—Th e headquarters f the Association in the city will be at Music Hall; there will = found the offices of the Permanent Secreta ary and Local Com- mittee, as well as the rooms for the sessions, and the book for registering the names of members on their arrival. e so-called Cosmical Dust.—Dr. Lasautx has investi- re Adee subject of the mineral dust chiar at different times has been collected at various points on the earth’s surface and sas which a cosmical origin has been assumed. The memoir by denskidld on this subject, noticed in this Journal, ix, 145, 1875, is reviewed and so he abel a gaia there reach d questioned n named by Nowdenskiotd Ra was examined micro econ outa of a es cae of snow collected by the author in ood o eral to regarded as terrestrial detritus, and that before a paadgamiee so origin can be considered proved in any case, a much more critical hag epee examination must be made than has been customary in the past AMERICAN JOURNAL OF SCIENCE. [THIRD SERIES.] Art. X V.— Upon a modification of Wheatsione’s Microphone and its applicability to Radiophonic Researches; by ALEXANDER GRAHAM BELL. [A paper read before the Philosophical ee of Washington, D. C., June 11, 1881. In August, 1880, I directed attention to the fact that thin disks or diaphragms of various materials become sonorous when exposed to the action of an intermittent beam of sunlight, and I stated my belief that the sounds were due to molecular dis- turbances produced in the substance composing the diaphragm.* Shortly afterwards Lord Raleigh undertook a mathematical investigation of the subject, and came to the conclusion that the audible effects were caused by the bending of the plates under unequal heating.t This explanation has recently been called in question by Mr. Preece, who has expressed the opinion that although vibrations may be produced in the disks by the action of the intermittent beam, such vibrations are not the cause of the sonorous effects observed. According to him, the aerial disturbances that produce the sound arise spontaneously i in the air itself by sudden expansion due to heat communicated from the dia pratt e increase of heat giving rise to a fresh pulse of air. Mr. Preece was led to Fools the theoretical ss of Lord Raleigh on account of the failure of experi- ments undertaken to test the theory. n Association for the Advancement of erage: ae 27, 1880. ieee a xxiii, p. 274. t Roy. Soc., March 10, 1 Am. Jour. Sct. e Series, Vor, XXII, No, 128. perenne 1881. 88 A. G. Bell—Applicability of a modification of He was thus foreed—by the supposed insufficiency of the explanation—to seek in some other direction the cause of the phenomenon observed, and, as a consequence, he adopted the ingenious hypothesis alluded to above. But the experiments which had proved unsuccessful in the hands of Mr, Preece were perfectly successful when repeated in America under better conditions of experiment, and the supposed necessity for another hypothesis at once vanished. I have shown, in a recent paper read before the National Academy of Science,* that audi- le sounds result from the expansion and contraction of tlie material exposed to the beam; and that a real to-and-fro vibra- tion of the diaphragm occurs capable of producing sonorous effects. It has occurred to me that Mr. Preece’s failure to detect with a delicate microphone the sonorous vibrations: that were so easily observed in our experiments might be explained upon the supposition that he had employed the ordinary form of Hughes's microphone shown in fig. 1, and that the vibrating ; area was confined to the central portion of the disk. Under such circumstances A Sy SIE it might easily happen that both the \ 5 supports (A, B,) of the microphone might touch portions of the diaphragm which Z were practically at rest. It would of course be interesting to ascertain wheth- er any such localization of the vibration as that supposed really occurred, and I have great pleasure in showing to you t u e B, carbon supports ; . ‘ . ” ; : Bg baa PP vba: A point has been investigated The instrument is a modification of the form of microphone devised in 1827 by the late Sir Charles Wheatstone, and it con- sists essentially of a stiff wire (A), one end of which is rigidly attached to the center of a metallic diaphragm (B). In Wheat- stone’s original arrangement the diaphragm was placed directly against the ear, and the free extremity of the wire was rest against some sounding body—like a watch. In the present arrangement the diaphragm is clamped at the circumference like a telephone-diaphragm, and the sounds are conveyed to the ear through a rubber hearing tube (c). e wire passes through the perforated handle (D) and is exposed only at the extremity. When the point (A) was rested against the center of a diaphragm upon which was focussed an intermittent beam 0 sunlight, a clear musical tone was perceived by applying the ear to the hearing tube (C). The surface of the diaphragm was * April 21, 1881. Wheatstone’s Microphone to Radiophonic researches. 89 then explored with the point of the microphone, and sounds were obtained in all parts of the illuminated area and in the errespand "a area on the other side of the diaphragm. Out- e of this area on both sides of the diaphragm the sounds baud weaker and weaker, until at a certain distance from the center they could no longer be perceived. t the points where one would naturally place the supports of a yore 2 microphone (see fig. 1) no sound was observed. We were also unable to against the support to which the diaphragm was attached. The negative results obtained in Ku- tion of vibration occurre in: the case of a large me- tallie mass. An inter- mittent beam of santigie was focussed upon a brass weight (1 kilogram), and - the surface of the weight A, stiff wire ; B, diaphragm ; ©, hearing tube; was then scplaee with D, perforated handle. Figure reduced one-half. ee microphone shown in fig. 2. A feeble but distinct sound s heard upon touching the surface within the illumin- ited area and for a short satmilas outside, but not in other parts n this experiment, as in the case of the thin diaphragm, abso- tile: contact between the point of the microphone and the sur- face brah was necessary in order to obtain audible effects. Now I do not mean to deny that sound waves may be origin- ated i in the moe suggested by Mr. Preece, but I think that our experiments have demonstrated that the kind of action described by Lord Raleigh actually occurs, and that it is suffi- cient to account for the audible effects observed. 90 O. N. Rood—Obtaining and measuring very high Vacua Arr. XVI.—On a method of obtaining and measuring very high Vacua with a modified form of Sprengel-pump ; by OapEeNn N. Roop, Professor of Physics in Columbia College. In the July number of this Journal] for 1880, I gave a short account of certain changes in the Sprengel-pump by means of which far better vacuua could be obtained than had been pre- viously possible. For example, the highest vacuum at that time known had been reached by Mr. Crooks, and was about aaaeeas While with my arrangement vacuua of zgp-pho-70T were easily reached. In a notice that appeared in “ Nature” for August, 1880, p. 875, it was stated that my improvements were not new, but had already been made in England four ears previously. I have been unable to obtain a printed ac- count of the English improvements, and am willing to assume that they are identical with my own ; but, on the other hand, as for four years no particular result seems to have followed their introduction in England, I am reluctantly forced to the conclu- sion that their inventor and his customers, for that period of time, have remained quite in ignorance of the proper mode 0 utilizing them. Since then I have pushed the matter still far- ther, and have succeeded in obtaining with my apparatus vacuua as high as z55-y45-g9p) Without finding that the limit of its action had been reached. The pump is simple in construc- tion, inexpensive and, as I have proved by a large number 0 experiments, certain in action aad easy of use: stopcocks and grease are dispensed with, and when the presence of a stopcock is really desirable its place is supplied by a movable column of mercury. cury and aor through a little watch-glass-shaped piece of sheet-iron, W, figure 1, which prevents the small air bubbles that creep upward along the tube from reaching its open end; the little cup is firmly cemented in its place. The flow of the mercury is regulated by the steel rod and cylinder OR, figure 1. The bottom of the steel cylinder is filled out with a circular piece of pure india-rubber, properly cemented; this soon fits itself to the use required ie answers admirably. The pres sure of the cylinder on the end of the tube is regulated by the lever 8, figure 1: this is attached to a circular board which with a modified form of Sprengel-pump. 91 again is firmly fastened over the open end of the bell-glass. It will be noticed that on turning the milled head 8, the motion of the steel cylinder is not directly vertical, but that it tends to describe a circle with ¢ as a center; the necessary play of the cylinder is however so small, that practically the experimenter » does not become aware of this theoretical defect, so that the arrangement really gives entire satisfaction, and after it has been in use for a few days accurately controls the flow of the mercury. The glass cylinder is held in position, but not sup- ported, by two wooden adjustable clamps aa, figure 2. The weight of the cylinder and mercury is supported by a shelf, 8, figure 2, on which rests the cork of the cylinder; in this way all danger of a very disagreeable accident is avoided. Vacuum-bulb.—Leaving the reservoir, the mercury enters the vacuum-bulb B, figure 2, where it parts with most of its air and moisture; this bulb also serves to catch the air that creeps into the pump from the reservoir, even when there is no flow of mercury ; its diameter is 27™™, The shape and inclination of the tube attached to this bulb is by no means a matter of indifference; accordingly figure 3 is a separate drawing of it; the tube should be so bent that a horizontal line drawn from po e the tube EC should be 150™, that of the tube ED 45™; the bore of this tube is about the same as that of the fall-tube, 92 O. N. Rood—Obtaining and measuring very high Vacua Fall-tube and bends.—The bore of the fall-tube in the pump now used by me is 1°78™™ ; its length above the bends (U, figure 2) is 310™; below the bends the length is 815™. ‘The bends constitute a fluid valve that prevents the air from returning into the pump; beside this, the play of the mercury in them greatly facilitates the passage of the air downward. The top of the mercury column representing the existing barometric pressure should be about 25™" below the bends when the pump is 1n action. This is easily regulated by an adjustable shelf, which is also employed to the bends with mercury when a meas- urement is taken or when the pump is at rest. On the shelf perforation can be easily made and shaped in a few minutes. By revolving the little bent tube through 180° the flow of the mercury can be temporarily suspended when it is desirable to change the vessel that catches it. ; Gauge.—For the purpose of measuring the vacua I have used an arrangement similar to McLeod’s gauge, fig. 4; it has, however, some peculiarities. The tube destined to contain the compressed air has a diameter of 1:35™, as ascertained by @ compound microscope; it is not fused at its upper extremity, but closed by a fine glass rod that fits into it as accurately as may be, the end of the rod being ground flat and true. This rod is introduced into the tube, and while the latter is gently heated a very small portion of the cement described below 1s allowed to enter by capillary attraction, but not to extend be- yond the end of the rod, the operation being watched by a lens. The rod is used for the purpose of obtaining the compressed air in the form of a cylinder and also to allow cleansing of the tube when necessary. The capacity of the gauge-sphere was obtained by filling it with mercury ; its external diameter was sixty millimeters; for measuring very high vacua this is some- what small and makes the probable errors rather large; would advise the use of a gauge-sphere of about twice as great capacity. The tube CB, figure 4, has the same bore as the measuring tube in order to avoid corrections for capillarity- The tube of the gauge CD is not connected with an india-rub- ber tube, as is usual, but dips into mercury contained in a cylinder 340™" high, 58™" in diameter, which can be raise and lowered at pleasure. This is best accomplished by the use of a set of boxes of various thicknesses, made for the purpose and supplemented by several sheets of cardboard and even ° writing-paper. These have been found to answer well and enable the experimenter to graduate with a nicety the pressure with a modified form of Sprengel-pump. 93 to which the gas is exposed during measurement. By employ- ing a cylinder filled with mercury instead of the usual caoutch- ouc tubing small bubbles of air are prevented from entering the gauge along with the mercury. An adjustable brace or support is used which prevents accident to the cylinder when the pump is inclined for the purpose of pumping out the vacuum-bulb, The maximum pressure that can be employed in the gauge used by me is 100™™. the tubing of the pump is supported at a distance of about 55™= from the wood-work ; this is effected by the use of simple adjustable supports and adjustable clamps; the lat- ter have proved a great convenience. The object is to gain the ability to heat with a Bunsen burner all parts of the pump without burning the wood-work. Where glass and wood nec- essarily come in contact the wood is protected by metal or simply painted with a saturated solution of alum. The glass portions of the pump I have contrived to anneal completely by the simple means mentioned below. If the glass is not an- nealed it is certain to crack when subjected to heat, thus caus- ing vexation and loss of time. The mercury was purified by the same method that was used by W. Siemens (Pogg. Anna- len, vol. cx, p. 20), that is, by a little strong sulphuric acid to which a few drops of nitric acid had been added ; it was dried by pouring it repeatedly from one hot dry vessel to another, by filtering it while quite warm, the drying being completed finally by the action of the pump itself. All the measure- ments were made bya fine cathetometer which was constructed for me by William Grunow; see this Journal, Jan., 1874, p. 23. It was provided with a well-corrected object-glass having a focal length of 200™", and as used by me gave a magnify- - Ing power of 16 diameters. Manipulation.—The necessary connections are effected with a cement made by melting Burgundy pitch with three or four per cent of gutta percha. It is indispensable that the cement when cold should be so hard as completely to resist taking any impression from the finger nail, otherwise it is cer- tain to yield gradually and finally to give rise to leaks. The connecting tubes are selected so as to fit as closely as possible, and after being put into position are heated to the proper amount, when the edges are touched with a fragment of cold cement which enters by capillary attraction and forms a trans- parent joint that can from time to time be examined with a ens for the colors of thin plates, which always precede a leak. Joints of this kind have been in use by me for two months at a time without showing a trace of leakage, and the evidence gathered in another series of unfinished experiments goes to show that no appreciable amount of vapor is furnished by the - 94. O. N. Rood—Obtaining and measuring very high Vacua resinous compound, which, I may add, is never used until it has been repeatedly melted. As drying material I prefer caustic potash that has been in fusion just before its introduc- tion into the drying tube; during the process of exhaustion it can from time to time be heated nearly to the melting point ; _ if actually fused in the drying tube the latter almost invaria- ly cracks. The pump in the first instance is to be inclined at an angle of about 10 degrees, the tube of the gauge being supported by a semicircular piece of thick pagte-board fitted with two corks into the top of the cylinder. This seemingly awkward proceeding has in no case been attended with the slightest accident, and owing to the presence of the four level- ing-screws the pump when righted returns, as shown by the telescope of the cathetometer, almost exactly to its original place. In the inclined position the exhaustion of the vacuum- bulb is accomplished along with that of the rest of the pump. The exhaustion of the vacuum-bulb when once effected can be preserved to a great extent for use in future work, merely by allowing mercury from the reservoir to flow in a rapid stream at the time that air is allowed to reénter the pump. “During the first process of exhaustion the tube of the gauge is kept hot by moving to and fro a Bunsen burner, and is in this way freed from those portions of air and moisture that are not too firmly attached. After a time the vacuum bulb ceases to de- amount of air that was detached from the walls of the pump by heating them for 10 minutes somewhat above 100° C., and found that it was z—yyb-sy5 of the air originally present. 1 have also noticed that a still larger amount of air is detached by electric discharges. This coincides with an observation of K. Bessel-Hagen in his interesting article on a new form of Topler's mercury-pump (Annalen der Physik und Chemie, 1881, vol. xii). Even when potash is used a small amount of moisture always collects in fe bends of the fall-tube ; this is readily removed by a Bunsen-burner ; the tension of the vapor being greatly increased, it passes far down the fall-tube in large with a modified form of Sprengel-pump. 95 bakkie and is condensed. Without this precaution I have poe it impossible to obtain a vacuum higher than gs-gyy-g00 point of fact the bends should always be heated when a igh exhaustion is undertaken even if the pump has been standing well exhausted for a week; the heat should of course never be ne at a be stage of the exhaustion. Convers sely, I have often by t of heat completely and quickly removed quite large spiatitiek of the vapor of water that had oa purposely introduced. The exhaustion of the vacuum-bulb is of course somewhat injured by the act of using the pump mis also by standing for several days, so that it has been usual with me before undertaking a high exhaustion to incline the pump and reéxhaust for 20 minutes; I have however obtained very high vacua without using this precaution. During the process of exhaustion not more than one-half of the mercury in the reservoir is. allowed to run out, otherwise when it is returned bubbles of air are apt to find their way into the vacuum-bulb. In order to secure its quiet entrance it is poured into a silk bag provided with several holes. When the reservoir is first filled its walls for a day or two appear to furnish air that enters the vacuum-bulb; this action, however, soon sinks to a minimum om then the leakage remains quite constant for months togethe Measurement of the Gacailtik —The cylinder into which the gauge-tube dips is first elevated by a box sufficiently thick merely to close the gauge, afterwards boxes are placed under it _ sufficient to elevate the mercury to the base of the measuring tube; when the mercury has reached this point, thin boards and card-boards are added till a suitable pressure is obtained. The length of the enclosed cylinder of air is then measured with the cathetometer, also the height of the mercurial “ menis- “te ” and the difference of the heights of the mercurial columns in A and B, figure 4. To obtain a second measure an assistant removes some of the boxes and the cylinder is lowered by hand three or four centimeters and then replaced in its original posi- tion. In measuring really high vacua, it is well to begin with this process of lowering and raising the cylinder, and to repeat it five or six times before taking readings. It seems as though the mereury in the tube B supplies to the glass a coat- ing of air that allows it to move more freely; at all events it is certain that ordinarily the readings of B become regular, only after the mercury has been allowed to play up and down the tube a number of times. This applies particularly to vacua as high as Frise and to pressures of five millimeters and under. It is advantageous in making measurements to a ded 96 O. N. Kood—Obtaining and measuring very high Vacua of these to each other. This I did quite elaborately, and proved that such constant errors as exist, are small, compared with inevitable accidental errors, as for example that there was no measurable correction for capillarity, that the calculated f the ‘‘meniscus” was correct, ete. It is essential in making a measurement that the temperature of the room should change as little as possible, and that the temperature of the mercury in the cylinder should be at least nearly that of the air near the gauge-sphere. The computation is made as follows: n=height of the cylinder enclosing the air ; e=a factor which multiplied by » converts it into cubic millimeters ; S=cubic contents of the meniscus ; d=ditference of level between A and B, fig. 4; =the pressure the air is under ; N=the cubic contents of the guage in millimeters ; t= pore expressing the degree of exhaustion obtained : | then A leer ne—§ It will be noticed that the measurements are independent of the actual height of the. barometer, and if several readings are taken continuously, the result will not be sensibly affected by a simultaneous change of the barometer. Almost all the read- ings were taken at a temperature of about 20° C., and in the present state of the work corrections for temperature may be considered a superfluous refinement. auge correction.—It is necessary to apply to the results thus obtained a correction which becomes very important when it is necessary to subtract the volume of this air from nc. By a series of experiments I ascertained that the amount of air introduced by the mercury in the acts of entering and leaving the gauge was sensibly constant for six of these single operations (or for three of these double operations), when they follow each other immediately. The correction accordingly is made as follows: the vacuum is first measured as described above, then by withdrawing all the boxes except the lowest, the mer- cury is allowed to fall so as nearly to empty the gauge; it is then made again to fill the gauge, and these operations are repeat until they amount in all to six; finally the volume and pressure with a modified form of Sprengel-pump. 97 area second time measured. Assuming the pressure to remain constant, or that the volumes are reduced to the same pressure, v=the original volume ; v'=the final vo : V'=volume of air introduced by the first entry of the mercury; V=corrected volume ; then _ vv nite oe V=v0— enet It will be noticed that it is assumed in this formula that the same amount of air is introduced into the gauge in the acts of entry and exit; in the act of entering in point of fact more fresh mercury is exposed to the action of the vacuum than in the act exit, which might possibly make the true gauge-correction rather _larger than that given by the formula. It has been found that when the pump is in constant use the gauge-correction gradually diminishes from day to day: in other words, the air is gradually pumped out of the gauge-mercury. Thus on December 21st, the amount of air entering with the mercury corresponded to an exhaustion o 1 nae enh Dee, 21st. 27 308 805 ee Tae Dec, 29th. a age. Jan. 15th. 83 943 ee oe on Sa OG 22 arene 1a, 1 | 396 757 400-77 7--E oP 9th. 1 nr ga eon bog tO ] 388 200 000 a ae a March 7th. ‘That this diminution is not due to the air being gradually withdrawn from the walls of the gauge or from the gauge-tube, is shown by the fact that during its progress the pump was several times taken to pieces, and the portions in question exposed to the atmosphere without affecting the nature or extent of the change that was going on. I also made one experiment which proves that the gauge-correction does not 98 O. N. Rood—Obtaining and measuring very high Vacua increase sensibly, when the exhausted pump and gauge are allowed to stand unused for twenty days Rate of the pump’s work.—It is quite important to know the rate of the pump at different degrees of exhaustion, for the pur- pose of enabling the experimenter to produce a definite exhaus- tion with facility ; also if its maximum rate is known and the minimum rate of leakage, it becomes possible to oo the highest vacuum oo with the instrument. amples are given in the tables below: the total capacity was ie abe 100, 000 cubic mm. Time. exhaustion. Ratio. 78 4511 1 10 minutes Seni sacs oh) sa gel dong sume 1 3°53 276 980 | 1h Gn Oe So. bio e 1 6°10 1 687 140 } 10 Mn OP es. Bs 1 4°15 7 002 000 Upon another occasion the following rates and exhaustions were obtaine Time. Exhaustion. Rate. 7 812500 1 Ty oiites se ee i ee | 3°18 24 875 620 1 10 mites a | ee ] 2°69 67 024 090 : 10 minutes Ce Oe tes 1 122 81 760 810 1 10 mins ee te 1 1°67 136 986 300 ‘ 10 wie 8 peice 1°23 1 170 648 500 The irregular variations in the rates are due to the mode in which the flow of the mercury was in each case regulated. with a modified form of Sprengel-pump. 99 Leakage.—We come now to one of the most important ele- ments in the production of high vacua. After the air is de- tached from the walls of the pump the leakage Geeanes and remains nearly constant. I give below a table of leakages, the pump being in each case in a condition suitable for the produc- tion of a very high vacuum : Duration of the Leakage per hour in cubic riment. mm., press. 760™™, 184 houres. 22 vot 000853 Ours. 2.0 7: ...°001565 264 nour “000791 Hhouree 622s. "000842 10 (ROU eh 000951 10> hour 5050.45 2001857 1 Gaye. 25.00, 001000 7 ORB coccrweaucn soy 001574 AVerage:. 2.555 001266 I endeavored to locate this leakage, and proved that one- quarter of it is due to air that enters the gauge from the top of its column of mercury, thus: Duration of the Gauge-leakage per hour in cubic experimen mm., press. 760™™, 1S boars 20 “Se 7ye 0002299 TGQQR Cc Wace ee *0004093 7 GSVOi Ee ees 0003464 AVORAPE Tose: 0003285 This renders it very probable that the remaining three- i isa ters are due to air given off from the mercury at g. 4, fro that i < the bends and at the entrance of the fall-tabe O, ‘fig. 3. er on some evidence will be given that renders it prob- able that the leakage of the pump when in action is about four times as great as the total leakage in a state of rest. would in a year amount to °488 cubic millimeters press. 76 60m, and ina ee of the above dimensions would exert a pres- sure of -0233™™ 100 0. N. Rood—Obtaining and measuring very high Vacua Reliability of results ; highest vacuum. The following are samples of the results obtained. In o case sixteen readings were taken in groups of four with the following result : Exhaustion. 1 74 219 139 78 533 454 79 = 272 1 68 503 182 Mean aise iahi! 74 853 449 Calculating the probable error of the mean with reference to abo the above four results it is found to be 2-28 per cent of the ‘quantity seeealy hi ed. igher vacuum measured in the same way gave the fol lowing results: 1 146 198 800 1 175 131 300 1 204 081 600 1 201 207 200 ; 1 j The mean is 178411934’ with a probable error of 5:42 per cent of the quantity involved. ive now an extreme case; only five single readings were taken ; these corresponded to the following exhaustions : 1 379 219 500 1 371 057 265 1 250 941 040 1 424 088 232 1 691 082 540 with a modified form of Sprengel-pump. 101 The mean value is gg7a4y-yy0; With a probable error of 10°36 per cent of the quantity involve Upon other ceeaetrs I have tea exhaustions of be bcs anc aessivaos~ «6 f: course in these cases a gauge-correction was applied ; the highest vacuum that I have ever obtained irre- spective of a gauge-correction was yz gp-s$z75y_ In. these cases and in general, potash was employed as the dr ying ma- terial ; I have found it practical, however, to attain vacua as high as 50-v00a00 10 the total absence of all such substances. The vapor of water which collects in bends must be removed from hee to time with a Bunsen-burner while the pump is in actio Tei is evident that the final condition of the pump is reached when as much air leaks in per unit of time as can be removed in the same interval. The total average leakage per ten minutes in the pump used by me, when at rest, was ‘000211 cubic mil- aw tie at press. 760™. Let us assume ren em leakage when € pump is in action is four times as gre s when at rest ; thee in each ten minutes ‘000844 mabe: Hannon press. 760™ would enter; this corresponds in the pump used by me to an exhaustion - of Veraheae if the rate of the pump is such as to remove one-half of the air present in ten minutes, then the highest attainable exhaustion would be gzg-gta-w00- n the same way it may be shown that if six minutes are re- ee obtained with a plain i ihe -pump.—I made a series of experiments with a plain Sprengel- -pump without stopeocks, and arranged, as far as possible, like the instrument just described. The leakage per hour was as follows: Duration of the Leakage per hour in sobic experinient. mm. at press. 760 a2 bout... a. “104868 S GBYS oe sn eae ia wes 04520 2 GBYR «365. 6. ORR1D 4 GBYS - os ek, Ueeee Mean? 66503000). O88 Chea the same reasoning as above we obtain the following e: 102 O. N. Rood— Obtaining and measuring very high Vacua, ete. Time necessary for removal Greatest attainable + the air. i : ] J0 mimites: 220.22. - oe 5 000 000 7°5 minutes , 2 eeatatean it DOR 000 7 O-0 NENULCR oo we — aaa 12 000 000 In point of fact the highest exhaustion I ever obtained with this pump was 5-37$-s53 from which I infer that the leakage I wish, in conclusion, to express my thanks to my assistant, Dr. Ihlseng, for the labor he has expended in making the large number of computations necessarily involved in work of this ind, New York, June 10, 1881 J. D. Dana— Origin of the Rocks of the Cortlandt Series. 108 Art. XIX. — Geological Relations of the Limestone me of Westchester County, New York; by JAMES D. Dan OrIGIN OF THE Rocks OF THE ‘* CORTLANDT SERIES.” e account of the cose Uh Cortlandt rocks* I rit a large part of them afford evidence of conformability to the associated schists and limestone strata of the country, as if one with them in metamorphic origin; and that if any were truly eruptive these were in part more recent than the limestone, since they cut through it at Verplanck Point. They hence present nothing against the chronological conclusion which has been reached. These rocks, however, are so limited in distribution, and so peculiar in composition—being often chrysolitic, always having soda-lime feldspar predominant, and containing little or no quartz—that it becomes an interesting question, Whence their ih interpolation among the schists and limestones of the region That the lithological facts may be in mind preparatory to ot following discussion I here re-mention the prominent kinds ro Soda-granite: granite-like, consisting chiefly of oligoclase sod biotite, with little quartz, and often ¢ ontaining some horn- blende; varying from coarse +s tine in grain, and very light-col- ored to black—the black very micaceous and fine-gr aine 2. Dioryte, Quartz-dioryte: chiefly oligoclase and hornblende, with more or less aba and a little quartz; varying from very coarse and geet ike to fine-grained. iefly the feldspar, andesite—or, more probably, its equivalent, "| of labradorite and 2 of ee ae er- sthene, with more or less augite and biotite; usually dark gray or reddish brown in color, and rather finely granular; the hyper- sthene often in small crystals seldom — a sixth of an inch in length, and never. in folia. sometimes a grayis -green pyroxene, Tt Chrysolitic Ren aeceiti chrysolitic pyroxenyte, with some elke nory * This shngin for September last, ITI, xx, 1 Am. Jour. Sor.—TuirD ing emma Vou. XXII, No. 128. eae 1881. 104 J. D. Dana—Origin of the Rocks of the Cortlandt? Series. Other constituents of these rocks are frequently apatite (which is often in unusual proportions), and more or less magnetite, pyr- rhotite and pyrite (the pyrite mostly confined to the soda-gran- ite and dioryte). In the many slices (over 60) which I have microscopically examined, I have found no glassy or unindividal- ized material, and no appearances of a fluidal character, except that of broken crystals or crystalline grains. o the description of the noryte before given I here add the results of a careful chemical analysis made in the laboratory of the Sheffield Scientific School of Yale College (under Professor O. D. Allen) by Mr. M. D. Munn of that School. The specimen was from the northern half of Montrose Point, on the Hudson. Sid. AlO, FeO; FeO MnO MgO CaO Na.O K.O H,z0 1. 55°28 16°31 069 757 0-40 5°05 7:52 410 2°05 058 —99°55 2. 55°40 16°44 0°85 751 039 5°05 749 4:03 2°00 [0°58]—99°73 Mean 55°34 1637 O77 754 040 505 751 4:06 2°03 0°58 =—99-65 The evidence already presented with regard to the Cort- landt rocks sustains the conclusion, as I believe, that to 4 large extent at least they are of metamorphic origin; but that in the metamorphic process the original beds were rendered (through the heated moisture concerned in the metamorphism), more or less plastic or mobile, so that they thus lost all, or the most of, their original bedding, and that, as a consequence. they formed in some places intrusive dikes or veins intersect- ing other rocks having all the characteristics of eruptive rocks. J. D. Dana—Origin of the Rocks of the Cortlandt Series. 105 ern and southern limits, only ingredients occurred for making common mica schists and gneisses with subordinate layers of hornblende schist ? Before proceeding to this topic I will first mention the facts as to the special geographical position of the area covered by the Cortlandt rocks; and, secondly, briefly review the evi- dence as to their metamorphic origin. We shall then be pre- pared to enquire into the source or sources of the material. 1. Geographical Position of the Area. The small region of Cortlandt rocks is situated in the vicin- ity of the Hudson, near where this river leaves its channel through the Archean Highlands. This relation to the posi- tion of the Archean and the river channel is shown on the following map (p. 106). Upon it, the Archzean area is the black portion dotted with small vs, crossing the Hudson, from southwest to northeast, between Moodna and Fishkill on the north and Peekskill on the south: and the Cortlandt rocks occupy the area east of the Archean, south and southeast of Peekskill on the east of the Hudson, and on Stony Point (S on the west side of this river. Near Peekskill the Cortlandt area is separated from the Archean by belts of limestone (hori- zontally lined on the map), quartzyte, argillyte-like hydromica schist and mica schist, in all one to three miles in width; and that of Stony Point has, between it and the Archean, a contin- uation of the same rocks (the limestone area on the map being, as elsewhere, horizontally lined, and that of the slates, Shih are partly quartzyte, distinguished by a vertical lining with white and dotted bands). The portion of the map north of the Ar- chean and occupying valleys within its area, has been already explained as Lower Silurian; (1) limestone, (2) slates or schists (vertically lined), and (8) quartzyte (dotted), the limestone and schist in places fossiliferous; and as part of the great for- mation which comprises and is continuous with the true Ta- conic schists and limestone to the northeast, and the recog- nized Lower Silurian rocks of New Jersey and the States to the southwest. 106 J. D. Dana—Origin of the Rocks.of the Cortlandt Series. more distinctly before the reader, and especially the relations of Stony Point to Montrose Point and other places on the eas side of the Hudson. The eastern outline of the Archean makes a large angle at the crossing of the Hudson (the course on the west being north- east, and that on the east, east-northeast), so that the form was, thus far at least, favorable for the existence there of a broac bay in the Lower Silurian sea. The river-channel through the Map of parts of New York and New Jer- . i =| sey: ST, Stony Poi the Hudson; v, Verplanck Point, on the east side; cR, limestone about Cruger’s Station. Scale, 10 miles to 1 inch. B UIA Il ARCH AAN LIMESTONE NE . “ey acti Tas ce ps ee ee Pu. WESEPOLN Te vee * Ve FE , 2 cd Lat ” FRANKLIN ed ee Highlands had not yet been made, as is indicated by the con- tinuity of the Lower Silurian beds on the north of the High- and area across from Fishkill, and that of the same on the south across from Peekskill. 1e Lower Silurian ocean ex- tended over the Cortlandt area, and here were spread out the sand-beds and muds that now constitute the quartzyte and slates of the Potsdam or Primordial (Cambrian) period and the material of the limestone formation. North of the Archxat, in the Fishkill, Newburgh and Poughkeepsie regions, fossils found in the limestones and hydromica schist have demonstrated ~™ that the beds there are beyond question Lower Silurian ; and J. D. Dana— Origin of the Rocks of the Cortlandt Series. 107 the like.conformable association of quartzyte, slate and semi- crystalline limestone in the Peekskill region, together with their Peexsx YP Map of part of Western Cortlandt, showing the Peekskill, Verplanck, Tom Cove, and Cruger limestone areas, by horizontal lin pkins ing. Scale, 1 inch to a mile. unconformability to the Archean, and their relation to New ersey limestones have been adduced, in my former paper, as proof of a like Lower Silurian age for the Peekskill beds. 108 J. D. Dana— Origin of the Rocks of the Cortlandt Series. A freshwater stream must have emptied into this Cortlandt bay near the present channel of the Hudson; for the general sur- face of the Highland area and the course of the existing streams over its surface have a pitch southward ; but the length of this young Hudson River could hardly have equalled ten miles ; for these old lands, as the Lower Silurian in its valleys prove, stood at a lower level than now. This little stream was the chief one that gave aid to the ocean’s waters in the work of dis- tributing Archean detritus over the Cortlandt area. Nothing could have come down the valleys called Canopus Hollow and Peekskill Hollow; for these were for several miles arms of the sea in which limestone beds were accumulating. The cut through the Highlands now occupied by the Hudson was prob- ably begun ina fracture during the making of the Green Moun- tains at the close of the Lower Silurian. 2. Metamorphic origin of the Rocks. The following are the principal points in the evidence sus- taining the view that the rocks are, to a large extent, meta- morphosed sedimentary beds. 1.) The mica schist or micaceous gneiss in several places graduates into the soda-granite along the plane of contact, though always rather abruptly. (2.) The soda-granite, near its junction with the schist, and sometimes remote from it, contains, at short intervals, distinct layers of the schist, in positions conformable to the bedding outside, and single beds of this kind are in some cases contin- uous beds for 200 feet or more. e mica schist at Cruger’s in some parts contains beds that consist largely of staurolite, fibrolite, and magnetite (all infusible species), with abundant scales of silvery mica, a min- eral that fuses with great difficulty ; and the layers of schist which are in the soda-granite, just north, have a similar consti- tution ; as if they owed their resistance to the fusion which the rest experienced because of their consisting chiefly of these re- fractory materials, 4, e noryte and chrysolite rocks contain, occasionally, similar included conformable beds of schist; and some of these are beds of magnetite and corundum, with fibrolite, that is, are beds of emery ; and the noryte is sometimes crossed by gneissi¢ layers and has occasional planes of bedding parallel to the bedding of the limestone near by. 5.) Since ascending lavas have the motion of a fluid, deter- mined partly as to direction of movement by the friction along the sides, a layer of schist 50 or 100 feet long falling into it wou t remain entire, and parallel or conformable to the original schistose rock; and much less could a series of such J. D. Dana— Origin of the Rocks of the Cortlandt Series. 109 layers retain such ae Facts like these are not con- sistent with the theory of an eruptive origin. Moreover the schists are so firm rocks that the separation of vets by such means would be impossible. I add one additional fact with regard to these large inclu- sions. In the brownish-black chrysolitic pyroxenyte which occurs along the south side of Montrose Point, there is a layer of impure, mostly uncrystalline, gray limestone, eighty feet long (and probably much longer, as this is only the length of the exposure), and twelve to eighteen inches wide. It contains some gray-green tremolite or actinolite in the outer portion, and much disseminated pyrite, and owing to the latter is — rusted. ; s almost an Fon pdesibulity that a thin bed of limestone 80 Phas log could by any means have got into the erupted roc and quite impossible that, if in, it should have held together, and retained from one end to the other, even approximately, a uniform strike and dip (N. 12° E., 70° W). (6.) At Verplanck Point, where what look like veins or dikes of pyroxenyte occur in the limestone, a4 are for the most part conformable to the limestone; as if they might be altered beds; and the more northern of these pseudo-veins consist of mica schist; further, these pseudo-veins of the Point are represented half a mile northeast in the line of strike b eds of mica schist or hornblendic schist. Such facts appear to show that the most of the “veins” are beds, metamorphosed spathic, hornblendic or augitic, is eee of eruptive origin. s heat and mOrsrre may convert siliceous sand- ers under numerous examples show, may convert, by the recrystallization attending metamorphism, well- bedded strata of hornblendie, augitic or feldspathic material into a massive rock, often undis- tinguishable even bebe pa from an eruptive rock, One example in proof is given in my paper in the June number of ee Journal (p. 428); and others in papers on the Helderberg ocks of Bernardston, Mass., and Vernon, Vt.* The layer of * This Journal, III, vi, 339, 1873 and xiv, 379, 1877. 110 J. D. Dana— Origin of the Rocks of the Cortlandt Series. mostly uncrystalline limestone 80 feet long and a foot or more wide in the chrysolitic rock of Montrose Point indicates a tem- perature of metamorphism much below that of fusion. 3. Source of the material of the original beds. quartz. The three supposable sources of such characteristics are— (1) Detritus from the Archean Highlands. (2) Igneous eruptions, affording volcanic or igneous debris, in addition to ejected liquid rock, and along with more or less Archean detritus. (8) Detritus from the Highlands, supplemented by ingre- dients from the ocean. 1. ARCHHAN DETRITUS. agnesian as well as ferriferous sediments might therefore have come from such a source; and the frequent occurrence 0 hornblende schist in regions of the ordinary metamorphic rocks of Westchester County shows that their formation is nothing ex- ceptional. A feeble proportion of free quartz, as in the Cortlandt rocks, is not an uncommon fact. It characterizes muds or clays which have lost their quartz for making sand-beds 1m the separating process of wave-action or water-movement, an - it is exemplified in much hydromica schist, which often con- sists of hydrous mica alone, with little, if any, free quartz Again, the soda-lime feldspar, oligoclase, occurs in the granite and gneiss of the LR and, in fact, is common in these rocks wherever found, though in general subordinately to or thoclase; the Cortlandt rocks are peculiar only in the much larger proportion of soda-lime feldspars. In the Archean of the Adirondacks, labradorite rocks, closely like the noryte and J. D. Dana— Origin of the Rocks of the Cortlandt Series. 111 augite-noryte of Cortlandt in mineral constitution, cover wide regions; and the same kinds may have formerly existed in the Highlands north of the Cortlandt region, although they have not. yet been discovered there; and this is somewhat i oe Further: chrysolite, hone common in igneous pecan is also common as a metamorphic product, and occurs chloritic and mica schist and other ks as should be: ex- pected from its composition and gi ee heed by heat. Doubts with regard to Archean detritus as the only source of these Cortlandt rocks come from the ver abrupt transitions which exist between the hornblendic or augitic rocks and the ordinary mica schists and gneiss, so strongly exemplified in the Verplanck region; in the almost exclusive occurrence over so found in a similar way over any other part of Westchester County, the material of whose rocks, the limestones excepted, s sey Bightands (that of Greenwood Lake on the map, page 106), or on their western border, where sedimentary beds of High- land origin were extensively formed. The = border of the Archean in New Jersey is under Triassic beds, so that scarcely anything is known of the Lower Siaria strata directly southwest of Stony Point. 2. IGNEOUS EJECTIONS ALONG WITH MORE OR LESS ARCHHAN DETRITUS. In favor of igneous ejections as a chief source, there are the following facts. The larger part of the rocks are much like i igneous rocks. They resemble them (1) in mineral constitution; (2) in their soda-lime feldspars; (8) in the abundance of hornblende or poner and (4) in the feeble proportion of quartz. The noryte, though containing hypersthene, offers no objection to the view. a chrysolitic feature of the rocks of some parts of the region a frequent voleanic characteristic. ut while such resemblances to the igneous rocks exist, it is a striking fact (1) that nowhere in the region are the rocks col- umnar like those of the Palisades and many regions of augitic — rocks ; (2) that,no vents orjdikes have been {found to indicate the places of their ejection ; (3) that sometimes mix- tures of two or three kinds oecur—as hornblendyte, pyroxen- yte and augite-noryte—which were not combinations made separate ejections but are merely irregularities of constitution in a single large mass of rock; and occasionally Be noryte and 112 J. D. Dana— Origin of the Rocks of the Cortlandt Series. chrysolitic!hornblendyte are in united layers each only an inch or two thick ; and (4) there are transitions into mica schists not thus easily explained. hese objections appear to prove that the rocks are not truly eruptive. But they do not make it sure that they have not originated in depositions of vol- eanic debris or cinders (lapilli, badly called ‘voleanic ashes”), u —e. 0 Oe tive rocks; (2) mixtures of the extremest kind observed might h o. abrupt transitions from cinder- made beds to those of ordinary , , AO, Soe = My i JZ SS WZ wenneeewrenanen, oe =: iS s Ss 0 AMES RR Oo CKS = a, a. ‘ Aa - > S\\) Re a4 SS % lings PS Wi B =. tS =a nt Eo eg Zi LZ nce a ae : Ye S ZZ ZIME STONE - i) SSS CONGLOMERATE fi PhotoE lectra CONY. sediments might result, even to the intercalation of a layer limestone or mica schist, or magnetic iron, or emery, ures presented by the rocks described ; and even if, in the pro- cess, the heat had not reached that of fusion, portions of the beds permeated with heated moisture might. have become J. D. Dana— Origin of the Rocks of the Cortlandt Series. 118 plastic and have “a injected into fissures so as to produce ike-like veins, and might retain internal marks of their former mobility in broken cr poser if not in other evidences of wing. As to the centers of eruption, it is to be noted that the occur- granite, may be an indication that one of them was located in what is now the river channel off the Verplanck shores. (See map, p. 107). Since my former account of Stony Point was published I have made a further examination of the region with reference to this and other points. The chief facts as to the distribution and positions of the rocks are given in the preceding map.* The mica schist of the northwest and south sides of the Point join over the southwestern side; and the strike and dip show that there is here one stratum in a synclinal fold. Overlying the schist occurs the soda-granite in two areas; and next comes the chrysolitie rocks. The chrysolitic rocks thus occupy ap- proximately the middle setts of the synclinal.t e soda-granite is mostly of the coarsely’ crystalline, light- calored kind, looking like ordinary granite, but, in the vicinity of the schist, in some parts, a fine-grained variety, gray to black in color, occurs; and the fine variety sometimes intersects the coarse, or the reverse, as if in veins. In one case, near the *This map is based on a survey of the Point by Mr. L. Wilson, Principal of the mt institute, Haverstraw, N. Y., obligingly made at the request of +In + Tee ormer account of the Point, I 0 stratgrapically underlies the mica Sante it dipping aedor it, ‘as at Origers and ination confirms this conclusion. It is therefore a _It isa fact of interest that at Cruger’s this overlying schist is oka ey just like the overlying gueiss adjoining the limestone of New York Island. The fibrolitic gneiss of 123d street, on the corner of Tesxington babes ie put a few near the junction with the ravaeliie rock, occurs a thick stratum of. sieonauas : t 3 off to the northward with a nearly vertical dip (70°-80° N.) and a strike of N. 70° EK. The limestone is situated somewhat like the small beds in the interior of the the oat peninsula, and as near to the massive rock; the latter = proved In one case to be conformable to eras of bedding in the selghia ring noryte ; and in ustbet case, to the mica schist; but the relations of this Stony Point bed The Tompkins Cove limestone, on the shore just north of the limits of the above map contains many veins of quartz, and assays made fg the proprietor, Mr. Edward A. Swain, have proved that the quartz is aurifero 114 J. D. Dana—Origin of the Rocks of the Cortlandt Series. weakened, by finding that among the dikes of igneous rocks which intersect the Archzan in various places, some, or none, consist of rocks similar to those of Cortlandt. Professor Cook, in his Geological Report of 1868, at pag® 144, has described a labradorite rock, resembling somewhat the J. D. Dana—Origin of the Rocks of the Cortlandt Series. 115 Cortlandt noryte or augite-noryte, as occurring forty miles west the Hudson on the east slope of the Kittatinny Mountains, not far west of Libertyville and Deckertown (between c and d on the map, Plate 1x, in this Journal for last November) ; and and several miles long, coming in between the Hudson River slate and the overlying Oneida Conglomerate, and conforming to them in strike. In a recent letter to the writer he observes that the question as to whether eruptive or not he does not consider as settled, the debris of the region having prevented satisfactory examination. The adjoining slates are stated to be modified, as if from the influence of the mass, for 3,000 feet to the eastward—a distance so great that the effects can hardly be . all due to contact. The further study of that region may throw light on the Cortlandt rocks. (3.) ARCHHAN DETRITUS, SUPPLEMENTED BY MATERIALS FROM THE OCEAN, The chief stony materials which the ocean’s waters have to contribute are: (1) the calcareous—calcium carbonate mainly through the secretions (shells, corals, etc.) of its living species, and calcium chloride ; (2) the magnesian, from the magnesium chloride and sulphate; and (8) the soda, through the sodium chloride or common salt. he calcareous and magnesian materials of the oceanic waters have been of immense importance in rock-making. The limestones of the world have originated from the former. Be- sides this, few muds or neers sand beds have been made since the first Rhizopods Linas that have not contained more or less disseminated calcareous material ; and this material, in the course of the metamorphism of those beds, has been often employed in producing some of the new combinations constitut- ing metamorphic rocks. So, also, the ocean has been the chief source of the magnesia used for making dolomite, or magnesian limestone, and for other purposes. In the case of the limestone of Westchester County, which is dolomitic, pe magnesia was taken from the sea-water, according to the most generally ac- cepted view, while the process of consolidation was going on in great marshes of concentrated saline waters. into silicates, such as tremolite, white pyroxene, and other species; or, when iron cha also been present, into other related silicates of Tight or 7 ae gee tints, = hornblende, actinolite, green pyroxene so into other magnesian minerals through other ay of the limes ne. Thus the magnesia of the ocean’s waters has beyond doubt 116 J. D. Dana—Origin of the Rocks of the Cortlandt Serves. supplemented that of detritus in determining the constitution of metamorphic rocks, and has led especially to the production of different varieties of hornblende and pyroxene, the darker kinds resulting when the all-pervading ‘ingredient, iron, was present. ‘ Further, the ocean has been one of the sources of soda in rock-making. e contributions of this nature to sedimentary deposits, are, as is well known, common and extensive. Beds of rock salt, sometimes of great thickness, occur in formations of various ages, from the Silurian to the present time; and mag- nesian salts, derived, directly or indirectly, from the same sea- waters that afforded the rock salt, are also frequently present. Moreover, brines from deep borings are common. It is-not necessary here to give details. I mention two American cases only, one relating to the Lower Silurian formation, and the other pertaining to the vicinity of the region under dis- cussion. The boring at the St. Louis Insane Asylum, reported upon by Mr. G. C. Broadhead, State Geologist of Missouri,* which netrated through Carboniferous and Lower Silurian strata nto the Archwan, reached a depth of 3,84384 feet. ‘Salt water” was obtained in the Lower Silurian (Magnesian lime- stone) at a depth of 1,220 feet and below. At 2,256 feet, the water contained 3 per cent of salt; at 2,957 feet, 44 per cent; at 3,293 feet, 2 per cent; and below 3,545 feet, 7 to 8 per cent. Prof. G. H. Cook, State Geologist of New Jersey, states in his Report for the year 1880, that from a boring in the Triassic sandstone at Patterson in that State (which is in the same geo- graphical region with the Cortlandt area, it lying to the east of the Archean Highlands) the water obtained at 2,050 feet af- forded, per gallon, 408°46 grains of sodium chloride, with 109-44 of magnesium chloride and 278°32 of calcium chloride —which shows the presence of about half the proportion of salt contained in sea-water, and of a much larger proportion of magnesium and calcium chlorides than sea water contains ; and Prof. Cook adds: “the questions suggested by finding the salt water must remain for the present unanswered, though the fact that the rock-salt of Kurope is found in rocks of the same age as this raises the question whether it may not also be found here.” Rocks containing salt in beds or brines have undoubtedly undergone metamorphism, and under conditions as to superil- cumbent formations which permitted of no escape of the so- dium, and which therefore would have forced it into chemical combination with the other materials present. And if it has entered into any minerals the feldspars must be among them, * Report on'the Geological Survey of Missouri for 1873-1874, 8vo, p. 32. 1874. J. D. Dana— Origin of the Rocks of the Cortlandt Series. 117 since these are the commonest of anhydrous sodium sili- cates. Science looks to the ocean for the boric acid of some minerals and the chlorine and iodine of certain silver ores and some voleanic products; and hence referring to it as a source of the more stable bases with which these were combined is not unreasonable. albite may have ‘ Messrs. F. Fouqué and Michel Lévy have recently made* quired proportions, and keeping it in prolonged fusion. ey have thus proved that the sodium of a sodium carbonate will, at a high temperature, enter into combination and make feldspars. The sodium of sodium chloride (common salt) of pro saliferous sedimentary stratum has therefore been put beyond question by actual experiment. Metamorphic heat would be as effectual; and, with the aid of moisture, probably at a lower temperature than that employed by Fouqué. schist contains, along a certain horizon, interrupted beds or lenticular masses of limestone—parts of which are more or less changed to serpentine and verd-antique marble; and below the limestone horizon, the schist, for a considerable thickness, con- tains irregular masses of labradioryte (labradorite-dioryte), the slaty-beds of the schist changing for short distances to labra- * Comptes Rendus, vol. Ixxxvii, pp."700 and 779, November, 1878. @ 118 J. D. Dana— Origin of the Rocks of the Cortlandt Series. dioryte and then back again to slate, in the most irregular way. The idea of an eruptive origin is utterly out of the question ; and that of a “ voleanic-ash” origin for the material has nothing to sustain it, since not even one small dike of igneous rock or any other evidence of igneous eruption older than Triassic has yet been found within a circuit of fifty miles; and what there are of veins in the older rocks are made of granitic or siliceous material. Since these isolated portions of massive labradioryte are parts of a stratum lying directly beneath the limestone: horizon, which stratum would be likely to be more or less cal- careous through an organic source, the lime of the labradorite in this rock may be only the calcareous portion of the original sediments; and what additional soda was needed may come from the permeating brine water. i ay illustrate the mode of origin of other metamorphic labradorite and oligoclase rocks. e hypothesis that the massive Cortlandt rocks were made by the above-explained method—that is from “ ordinary detri- tus supplemented by materials from the ocean ”-—is therefore not wholiy improbable. It is still less so when some details connected with it are considered. ing sea-marshes prevailed, or alternated with open seas, over the ao. ss can et ew Meteoric Iron. 119 equally good for all in the Cortlandt and Stony Point area, and forall variations in the kinds and the thicknesses of the rocks, and their intercalations. Whether true or not, it must, after the survey of the facts, be admitted to be nothing : agai nst it that the rocks are massive crystalline rocks ; that among them are hornblendic and augitic kinds containing soda-lime feldspars, and that some of them are chrysolitic. Having presented the claims of the three ch saan T leave the subject without expressing a personal opini he Appendix to this memoir, to which attusion has been made, will appear in a following Ph hie of this Journal. Art. XX.—On a new Meteoric Iron, of unknown locality, in the Smithsonian Museum; by Cuaries UPHAM SHEPARD. HAVING received a fragment from a meteoric iron, of un- known locality, belonging to the Museum of the Smithsonian Institution, I have made an examination of it with the follow- ing results: e mass was oval in form, with three or four Prominent knobs. Its weight was probably about six pounds. The fra ment for examination was separated se considerable facility. requiring only a few smart blows of the hammer; and re- schreibersite. After polishing, pial te ragm t had a somewhat whiter color than artificial iron. When pean) it showed a homogeneous, finely crystalline texture, and became still whiter in color. When viewed at fixed angles of reflexion, sur- face Hiciabee sinanltadieduly, after the: manner of s oligoclasite, thus rendering it probable that the byatallicatiei of the general mass was that of. a single individual, It is obscurely ager in some portions, with bars about gyth of an inch in thickness. But the most remarkable feature of the etched fast ie is its thickly dotted or punctate character; the dots which are very bright, instead of being salient points, are slightly concave. On the whole, therefore, this iron differs in structure from any meteoric iron thus far known. The composition, as determined by C. U. Shepard, Jr., is Cova 0.2.40. 0°539 Schreibersite (phloepinal of iron) -. 0°562—100°095 There are traces also of copper and tin. The poe sur- faces show no tendeny to deliquescence. Sp. gr.= Charleston, Feb. 19, 1881. Am. Jour, winationes Series, Von. XXII, No, 128.—Avaust, 1881. 120.) A. A. Michelson—The relative motion of the Earth ArT. XXI.—The relutive motion of the Earth and the Luminif- erous ether ; by ALBERT A. MICHELSON, Master, U. 8. Navy. optical media, partakes of the motion of these media, to an ex- tent depending on their indices of refraction. For air, this motion would be but a small fraction of that of the air itself and will be neglected. ssuming then that the ether is at rest, the earth moving through it, the time required for light to pass from one point to another on the earth’s surface, would depend on the direc- tion in which it travels. Let V be the velocity of light. v = the speed of the earth with respect to the ether. D = the distance between the two points. d the distance through which the earth moves, while light travels from one point to the other. d, = the distance earth moves, while light passes in the opposite direction. iad te the direction of the line joining the two points to coincide with the direction of earth’s motion, and let T = time required for light to pass from the one point to the other, and Ho i T, = time required to perform the journey if the earth were at rest. Then Pe e. and T se aeamns pre d, x v Fhe v v From sear eee we find d=D-— and dD ry D v whence dd aaa aad 1 ¥a5 ; noed al, nearly, and _yizh pager. Sal If now it were possible to measure T'—T’, since V and T, are known, we could find v the velocity of the earth’s motion directions from earth; but that for this purpose the observa tions of these eclipses must greatly exceed in accuracy those and the Luminiferous Ether. 121 which have thus far been obtained. In the same letter it was also stated that the reason why such measurements could not be made at the earth’s surface was that we have thus far no method for measuring the velocity of light which does not involve the necessity of returning the light over its path, whereby it would lose nearly as much as was gained in going. The difference depending on the square of the ratio of the two pb serapey according to Maxwell, is far too small to measu The follows is intended to show that, with a wave-length ellow light as a standard, the quantity—if it exists—is par Ae measurable. : D Using the same notation as before we have io, and oe The whole time occupied therefore in going and returning T+T, = If, however, the light had trav: eled in a direction at right angles to the earth’s motion it would be entirely unaffected and the time of going and return- ing would be, therefore, 25=2T,, The difference between the times T+T', and ci is oie, vw or nearly me, In the time ¢ the light would travel a dist- ance Ve=2VT,2,=2D05 That is, the actual distance the light travels in the first case 2 is greater than in the second, by the quantity 2D ictisa only the velocity of se earth in orbit, the rati . So 10 = 7 sae — approximately, and = 7" 100 000 000 If 1200 millimeters, or in a . of este light, 2 000 000, tl a 1en in terms of the same unit, aDy= rae If, therefore, an apparatus is so constructed as to permit two pencils of light, which have traveled over paths at right angles to each other, to interfere, the pencil which has traveled in the direction of the earth’s motion, will in reality travel ix of a wave-length farther than it would have done, were the earth at es he other pencil being at right angles to the motion would not be affected. 122 A. A. Atichelson —The relative motion of the Karth If, now, the apparatus. be revolved through 90° so that the second pencil is brought into the direction of the earth’s mo- tion, its path will have lengthened 100 wave-lengths. The to- : ee ‘ 8 tal change in the position of the interference bands would be oa of the distance between the bands, a quantity easily measurable. e conditions for producing interference of two pencils of light which had traversed paths at right angles to each other were realized in the following simple manner. ight from a lamp 4a, fig. 1, passed through the plane par- allel glass plate }, part going to the mirror c, and part being 1. _ reflected to the mirror d. The sexas mirrors c and d@ were of plane d glass, and silvered on the front surface. From these the light was reflected to b, where the one was reflected and the other refracted, the two coinciding along be. The distance bc being made equal to dd, and a plate of glass g being iatebaceed: in the path of the ray be, to compensate for: the thickness of the glass 0, which is traversed by the ra e , the two rays will have traveled over equal paths and are in condition to interfere. The instrument is represented in plan by fig. 2, and in per- spective by fig. 8. The same letters refer to the same parts in the two figures. iy y g The mirrors c and d were moved up as close as possible to the plate 4, and by means of the screw i the distances between oint on the surface of b and the two mirrors were made approximately equal by a pair of compasses. The lamp being and the Luminiferous Hther. 123 lit, a small hole made in a screen placed before it served asa point of light; and the plate 6, which was adjustable in two planes, was moved about till the two images of the point of light, which were reflected by the mirrors, coincided. Then a sodium flame placed at a produced at once the interference bands. These could then be altered in width, position, or direction, by a slight movement of the plate 6, and when the were of convenient width and of maximum sharpness, the = é q 2 sodium flame was removed and the lamp again substituted. he screw m was then slowly turned till the bands reappeared. They were then of course colored, except the central band, which was nearly black. The observing telescope had to be focussed on the surface of the mirror d, where the fringes were most distinet. The whole apparatus, including the lamp and the telescope, was movable about a vertical axis. It will be observed that this apparatus can very easily be 124. =A. A. Michelson—The relative motion of the Earth made to serve as an “interferential refractor,” and has the two important advantages of small cost, and wide separation of the two ils. The apparatus as above described was constructed by Schmidt and Heensch of Berlin. It was placed on a stone pier in the Physical Institute, Berlin. The first observation showed, however, that owing to the extreme sensitiveness of the instrument to vibrations, the work could not be carried on during the day. The experiment was next tried at night. When the mirrors were placed half-way on the arms the fringes were visible, but their position could not be measured till after twelve o’clock, and then only at intervals. When the mirrors were moved out to the ends of the arms, the fringes were only occasionally visible. It thus appeared that the experiments could not be per- formed in Berlin, and the apparatus was accordingly removed tig. 3 to the Astrophysicalisches Observatorium in Potsdam. Even here the ordinary stone piers did not suffice, and the apparatus was again transferred, this time to a cellar whose circular wa formed the foundation for the pier of the equatorial. _Here, the fringes under ordinary circumstances were sufli- ciently quiet to measure, but so extraordinarily sensitive was the instrument that the stamping of the pavement, about 100 meters from the observatory, made the fringes disappear entirely | inclined at an angle of about +26° to the plane of the equator, * and the Luminiferous Ether. 125 and at this time of the year the tangent of the earth’s motion in its orbit makes an angle of —234° with the plane of the equator ; hence we may say the resultant would lie within 25° of the equator. The nearer the two components are in magnitude to each other, the more nearly would their resultant coincide with the plane of the equator. n this case, if the apparatus be so placed that.the arms point north and east at noon, the arm pointing east would coincide with the resultant motion, and the other would be at right angles. Therefore, if at this time the apparatus be rotated 90°, the displacement of the fringes should be twice = or 0°16 of the distance between the fringes. Tf, on the other hand, the proper motion of the sun is small. compared to the earth’s motion, the displacement should be 5%, of ‘08 or 0-048. Taking the mean of these two numbers as the most probable, we may say that the displacement to be looked for is not far from one-tenth the distance between the fringes. The principal difficulty which was to be feared in making these experiments, was that arising from changes of tempera- ture of the two arms of the instrument. These being of brass whose coefficient of expansion is 07000019 and having a length of about 1000 mm. or 1700000 wave-lengths, if one arm should the instrument had to be returned to the maker, with instruc- tions to make it revolve as easily as possible. It will be seen from the tables, that notwithstanding this precaution a large displacement was observed in one particular direction. That his was due entirely to the support was proved by turning the latter through 90°, when the direction in which the dis- placement appeared was also changed 90°. n account of the sensitiveness of the instrument to vibra- correct to wifhin 3's. It frequently occurred that from some slight cause (among 126 A. A. Michelson—The relative motion of the Karth others the springing of the tin lantern by heating) the fringes would suddenly change their position, in which case the series of observations was rejected and a new series begun. In making the adjustment before the third series of observa- tions, the direction in which the fringes moved, on moving the elass late b, was reversed, so that the displacement in the third and fourth series are to be taken with the opposite sign. At the’end of each series the support was turned 90°, and the axis was carefully adjusted to the vertical by means of the foot-screws and a spirit level. N. NB. E. | S.B. 8. Sw. WwW. | NW. Remarks. Ist revolution} 0-0! 0-0) 0:0|—8-0|—1-0|—1-0|—2-0|—3-0|Series 1, footscrew 2d o 16:0} 16°0| 16-0} 9°0| 16°0| 16-0] 15-0) 13°0| marked B, toward 3d “ 17:0, 17-0) 17-0; 10°0) 17-0; 16-0) 16-0) 17°0| East Mth. {# 15:0) 15°0' 15-0] 8-0) 14°5| 14°5| 14°5| 14°0 ath st 13°5| 13°5| 13°5| 5:0} 12°0) 13:0) 13-0} 13-0 615) 61°5 61°5) a@ | 58°5| 58°5| 56°5| 54-0 S.| 58:5) W.) 56°5 N.E| 61°5| S.E.| 60-0 120°0 118°0 1120-0 1140 118-0 1140 i Excess, +2°0 Ist revolution 100] 11-0} 12°0| 13-0} 13°0| 0-0| 14°0| 15-0/Series 2, B toward 2d Ne South. 6°0| 16:0) 16 7-0} 17-0) 2°70) 17-0} 17-0 3d i i 17°5) 17-5) 17-5] 175) 4-0) 18-0) 17°5 4th & 175} 17°5) 17-0) 17-0} 17-0) 4:0) 17-0] 17°0 5th “ 17°0| 17-0] 17-0} 17-0] 16:0) 3:0) 16°0} 16°0 78:0} 79-0) 79°5| 81°5| 80°5| a | 82°0| 82°5 S.| 80°5| W 1) N. K,} 81- 80°5 E,| 79:0) § 5 158°5 1615 160°0 164-0 615 164-0 Excess, = '—3-0 ‘4:0 Ist revolution} 3:0] 3-0) 3°0| 3-0] 2:5! 2:5! 2-5! 10-0|Series 3, B toward 2d “ 18-0} 17°5| 17-5} 18-0} 18°65] 19-0] 19°5| 26°0| West. - 3d “ 11-0} 11-0) 13°0| 12°0| 13-0) 13-5) 13-5] 21-0 4th “ 10; 0°70) 0-5) 0-5] 05) 0-0) 0-0) 14-0 5th us 40} 40) 50) 5-0) 5 5°5| 5°] 16°0 37°0| 35°5| 39°0| 38°5| 39°35! 40°5| 7 S.| 39°56] W.) 41:0 35°5| S E.| 38°5 165 80°0 76-0 19°5 765 760 Excess, +3°5 +3°5 ant revolution leo 21-0] 15°5| 17°0| 14-0] 14°5| 14:5] 16-0\Scries 4, B toward 0} 12°0) 13°0} 13-0] 13°0) 13°5| North . ) 5 0 3d Ms ics 15°0} 16-0) 16°0) 16-0} 16-0) 17 4th a 18°0) 27-0} 18°5} 18°56) 18°5| 19-0] 20-0! 21-0 oth «“ 15°0| 24:0} 15-0} 15-0) 15-0) 16-0] 16°0| 16-5 71-0} a | 76°0| 78°5| 76°5| 78-5! 79-5) 84-0 S.| 765} W.) 79°5 E.| 73:5] S-E.| 78:5 M75 155°5 152-0 162°5| « 1475 152°0 Excess, +80 +10°5 and the Luminiferous Ether. 127 The heading of the columns in the table gives the direction toward which the telescope pointe The footing of the erroneous column is marked x, and in the calculations the mean of the two adieasts foaynes is sub- stituted. The numbers in the columns are the positions e the center of the dark fringe in twelfths of the distance between the fringes. In the first two series, when the footings of the columns N. and S. exceed those of columns KH. an , the excess is called positive. The excess of the footings of N. “4, OVEF. ‘those of N.W., S.E., are also called positive. “Tn the third and fourth series this is reverse e numbers marked “ excess” are the sums of ten observa- tions. Dividing therefore by 10, to obtain the mean, and also by 12 (since the numbers are twelfths of the distance between the fringes), we find for N.S. N.E., S.W. Sere foo +0°017 ‘050 2 2 -...—0°025 —0°033 ss k, Maun ieenaivaaneg tes +0°030 +0°030 Bead oe ce Ue +0°087 4 J 0-089 07137 Mean +0°022 + 0°034 The displacement is, therefore, Tn favor of the columns NM. eu eee ng +0°022 RO BW ee +0°034 The former is too small to be considered as showing a dis- placement due to the simple change in direction, and the latter should have been zero. he numbers are simply outstanding errors of experiment. It is, in fact, to be seen from the footings of the columns, that the numbers increase (or decrease) wit] more or less regularity from left to right. This gradual change, which should not in the least affect the periodic variation for which we are searching, would of itself necessitate an outstanding error, simply because the sum of the two columns farther to the left must ‘be less (or greater) than the sum of those farther to the ee This view is amply confirmed by the fact that where the ex- cess is positive for the column N.S,, it is also positive for N.E., S.W., and where negative, negative. If, therefore, we can. prea ase this gradual change, we may expect a much smaller error, This is most readily accomplished as follow dding together all the footings of the four rae the third and foutth with negative sign, we obtain N. N.E. EK. 8.K. 8. S.W. Ww. N.W. 305. BES 960 = kOe ee 128 A. A. Michelson—The relative motion of the Earth, etc. or dividing by 20X12 to obtain the means in terms of the distance between the fringes, N. N.E. E. S.E. : S.W. ; ; 0-131 O-131 0108 0°102 0:096 0-086 0-075 0-046 If a is the number of the column counting from the right and y the corresponding footing, then the method of least squares gives as the equation of the straight line which passes nearest the points x, y— y = 9°25x + 645 If, now, we construct a curve with ordinates equal to the difference of the values of 4 y found from the equation, and the actual value of y, it will Pca the displacements observed, freed from the error in ques These ordinates are: N. N.E. E. §.E. Ss. S.W. W. N.W. —'002 —'O11 +°003 — ‘001 — 004 — 003 —001 +°018 N. —*002 BE. +7003 N.E. —'011 N.W. +:°018 Ss. — "004 W. —'001 5.W. —°003 8.E. —-001 Mean= —-003 +°001 Mean= —:°007 +008 +°001 +°008 Excess= —'004 Excess=— ‘015 The small displacements —0°004 and —0°015 are simply errors of experiment. The results obtained are, acter more strikingly shown by constructing the actual curve together with the curve that should have been found if the theory had been correct. This is shown i in fig. +. Or The dotted curve is drawn on the supposition that the dis- placement to be expected is one-tenth of the mistante bein the fringes, but if this displacement were only +45, t roken line would age hae more nearly with ey Pilot line than with the ¢ e Sritenisell tof of these results is oof there is no dis- pee of the interference ban result of the ypothesis of a stationary ether is ins shown si be incorrect, and the necessary conclusion follows that the hypothesis 1s erroneous. This conclusion directly peepee the explanation of the phenomenon of aberration which has been hitherto generally -aceepted, and which presupposes ry the earth moves through the ether, the latter remaining at rest. E. 8. Holden—LTrght of Telescopes used as Night-glasses. 129 It may not be out of place to add an extract from an article published in the Philosophical Magazine by Stokes in 1846. “ All these results would follow immediately from the theory of aberration which I proposed in the July number of this magazine: nor have I been able to obtain any result admitting of being compared with experiment, which would be different according to which theory we adopted. This affords a curious instance of two totally different theories running parallel to each other in the explanation of phenomena. I do not sup- pose that many would be disposed to maintain Fresnel’s theory, when it is shown that it may be dispensed with, inasmuch as we would not be disposed to believe, without good evidence, decisive experiment.” n conclusion, I take this opportunity to thank Mr. A. Gra- ham Bell, who has provided the means for carrying out this work, and Professor Vogel, the Director of the Astrophysi- calisches Observatorium, for his courtesy in placing the re- sources of his laboratory at my disposal. Art, XXII.— Observations on the Light of Telescopes used us Night- Glasses ; by Epwarp 8. Honpen. ‘ In the Philosophical Transactions for 1800, vol. xe, p. 67, Sir William Herschel says: “In the year 1776, when I had erected a telescope of 20 feet focal length, of the Newtonian construction, one of its effects by trial was that when toward evening, on account of darkness, the natural eye could not pen- etrate far into space, the telescope possessed that power suffi- ciently to show, by the dial of a distant church steeple, what o'clock it was, notwithstanding the naked eye coald no longer see the steeple itself. Here I only speak of the penetrating power, for though it might require magnifying power to see the figures on the dial, it could require none to see the steeple.” I had long been desirous of trying this experiment with a large aperture, and made several attempts in 1874 to have the Dome of the 26 inch Clark refractor at Washington so arranged that a terrestrial object could be seen, but without success. I therefore took the first opportunity to try the effect of a tele- scope under these conditions at the Washburn Observatory, where the large equatorial commands the horizon. The most suitable object for examination was the tower of the Hospital 130 EH. & Holden—Light of Telescopes used as Night-glasses. for the Insane, which is 20,798 feet distant from the center of the Dome* 1” at this distance is 13 inches; 1’ is 78 inches. The accompanying figure will give the best idea of the object viewed. ‘The drawing has been kindly made for me by Shipman, Esq., of Chicago. I have marked upon the cut the line of the horizon, from sic it appears that the 10 6. Diam.66 000 eS Me cee ae s Sto _ ao" 5 EF | = F G ee teri d 22 6 es I Ps | 980" = a0 saa abit ae H H whole tower has an elevation of about 9’ above the horizon line, In the observations which follow, the part A B, (10 feet high), is spoken of as ‘the spire;” B G, (9 feet), as “the base . the spire ;” the next section, (13 feet high), as “ the cupola” “the dome,” and the remaining portion, as “the tower.’ he 2 finder has an aperture of 3°50 inches, a field of 1° 20%, and a magnifying power of 26 diameters. The refractor has an ay of 15°56 inches, a field of 11’-6, and a power of 199 iamete The following thee ea were made 1881, April 18, by Mr. 8. urnham and m The whole sky was pertectly eles except a very faint bank of clouds to the west of the tower looked at. The observations were as follows: Hn. standing for observations made by Holden ; for those made by Burnham * T have to express my thanks to Professor J. E. Davies for the sci cuitasiik tion of the Coast Survey data re atte these figures are derive B. 8. Holden—Light of Telescopes used as Night-glasses. 181 7" 35", The tower disappears to the naked eye. In the finder the spire is still plamly seen, In the 15-inch, the whole of the spire, ribs, dome and many details well seen.— Hn. 7" 42", The tower disappears to yh ar d eye. In the finder nd telescope everything still see ' 8" 0™, 15-inch: the ribs on the dapat Me are gone.—Hn. and f. 8" 7", Finder: the shape of the cupola is confused asi uncer- d 8" 14", Finder: pretty muchsthe same. 15-inch: the spire on top of the cupola is still plain. No one looking with the miss 1t.—Hn. and 8" 17", 15-inch: the spire on top of the cupola gone—Hn. I p. 817, Finder: all shape to the cupola is gone.— Hn, 8h ee ve inch: spire still seen by averted vision ; not well by 8" 22™, he the tower is a mere black spot. 15-inch: spire is much fainter.— 8° 23", 15-inch: the spire is gone, except that I can see that the outline of the cupola is not r — 8" 25™. 15-inch: spire gene 8.” 8 26". Finder: tower gone.—Hn. 8° 27". Finder: tower and cupola gone.—/f. 8° 27", 15-inch: tower and cupola gone.—Hn. 8 29", 15-inch: tower has lost all shape.—/. ; 8' 30", 15-inch: tower gone.—/f. rota i time mi sky was dark and the horizon Lapras clearer shown by small stars becoming visible the | finder, Probably the light Send above spoken of was snuipatad, 8" 35", 15-inch: the cupola and tower can be plainly seen as a dusky cloud with a certain shape, when the telescope is vibra- nm. and fp. 8° 37". 15-inch: pis 7 and 8" 43", 15-inch: the cupola and tower are seen even better than before. The horizon is clearer. There is no difficulty in see- th them when the telescope is moved, and they can just be seen by direct vision.—/. 8" 44", Same.—Hn. and f. 8" 45", Stopped examination as there seemed to be no prospect of losing the tower as long as the horizon remained clear we had lost it we should have attributed the loss to haze at the horizon. Small stars 8-9 magnitude seen fr finder, They must have had an altitude of not more than 30’, It appears to me that this confirmation of Hersch $ experi- ments is important, and worth the attention of physicists. So far as I know there is no satisfactory explanation of the action of the ordinary eae seas, nor of the similar effect when large apertures are u Washburn Observatory, sane 1881, May 1, 132 Whitfield and Dawson—Nature of Dictyophyton. Art. XXIIT.—On the nature of Dictyophyton; by R. P. Wurr- FIELD. With a note, by J. W. Dawson. _ SINCE writing the article on Dictyophyton published in the last number of this Journal I have obtained additional evi- dence of their spongoid character. About the middle of May, while discussing their nature with Principal Dawson, of Mon- treal, we examined some allied forms from the Keokuk beds at Crawfordsville, Indiana, which lately came into the possession of the American Museum of Natural History, and found one which retained the substance of the organism. Under a hand- lass of moderate power it is seen to have been composed of cylindrical threads of various sizes, now replaced by pyrite. ith the means then at our command it was impossible to fully determine whether they had been bundles of vegetable fibers or sponge-like spicules; but Dr. Dawson kindly offered to examine them more critically if I would forward a specimen to him at Montreal. This was done, and his note on their na- ture is appended below. The specimen used probably belongs to the genus Uphantaenia Vanuxem, and is a fragment about 24 by 3 inches across and seems to have been a part of a circu- lar or discoid frond of 8 or 10 inches diameter. It differs from Uphantaenia Chemungensis of New York in many features. The broad, radiating bands are more distant, with a n«rrow, _ thread-like band between; while all the circular bands have been narrow or thread-like. The spaces between the bands and threads are rectangular and covered by a thin film which is alternately elevated or depressed in the adjoining spaces, as if the bands had been elastic like rubber and had contracted, wrinkling up the intermediate spaces. A. fnrther description and illustration of the form I shall defer to a future occasion, but shall here designate the species as Uphantaenia Dawson. The broad bands are composed of very fine thread-like spicules, and the narrow ones of much stronger ones, while the thin film occupying the intermediate spaces is composed of still smaller spicules apparently arranged in radiating manner. The char- acter and nature of tiese threads and spicules are well set forth in Dr. Dawson’s notes below, and the spongoid features and relations to Huplectella indicated. ° Note by Dr. J. W. DAWSON on the Structure of a specimen of Uphantaenia, from the Collection of the American Museum of Natural History, New York City. To the naked eye the fossil presents rectangular meshes of dark matter on a gray finely arenaceous matrix. The spaces of the network are of an average size of 6™ in length and 4 or 5 Whitfield and Dawson—Nature of Dictyophyton. 133 in breadth. The longitudinal bands are ooo 3™™ broad, the transverse bands much narrower. Some of the rectangular in- terspaces are of the color of the ae athe wholly or par- tially stained with dark matter. e meshes are near! y black, but ina bright light show a fibrous texture and metallic lus- ter due to pyrite. Viewed as opaque objects under the microscope, the reticu- lating bands are seen to be fascicles of slender cylindrical rods or spicules, varying much in diameter; some of the largest being in the narrow transverse bands. The spicules may, in a few cases, be seen to be tapering very gently iis a point, but usually seem quite cylindrical and smooth. their present state they appear as solid phining a of ete The largest spicules are about 335 of an inch in diameter ; baa smaller n the whole the structures are not ideutiaal with those of any vlan ee to me, and rather resemble those of siliceous sponges of the genus Huplectella, e most puzzling fact in connection with this view is the mineral condition of the spicules now wholly replaced by pyrite. Carbonaceous structures are often replaced in this way s siliceous organisms. If the spicules were originally siliceous, either they must have had large internal cavities which have been filled with pyrite, or the original material must have been wholly dissolved out and its place occupied with pyrite. It is to be observed, however, that in fossil sponges the siliceous matter has not infrequently been dissolved out, and its space left vacant or filled with other matters. ave specimens of Actylospongia from the ‘Nant formation which have thus ager replaced by ae of a ferruginous color; and in a bundle of fibers probably a sponge allied to Hyalonema from the Piandailo of of Scotland, I find the substance of the spicules entirely gone and the spaces ‘formerly occupied by them empty. It should be added that joints of Crinoid stems and fronds of Fenestella occurring in the same specimen with the Uphantaenia are apparently in their natural calcareous state. Though I have hitherto regarded this curious organism as a fucoid, I confess that the study of the specimen above referred to inclines me to regard it a more preety a sponge. I owe the opportunity of examining this very interesting specimen to the kindness of Sheath Whitfield. 1384 H. Draper—Photographs of the Spectrum of the Comet. Art. XXIV.—Note on Photographs of the Spectrum of the Comet of June, 1881; by Professor HENRY DRAPER, M.D. THE appearance of a large comet has afforded an opportunity of adding to our knowledge of these bodies by applying to it a new means of research. Owing to the recent progress in pho- tography, it was to be hoped that photographs of the comet and even of its spectrum might be obtained and peculiarities invisible to the eye detected. For such experiments my observatory was prepared, because for many years its resources ad been directed to the more delicate branches of celestial photography and spectroscopy, such as photography of stellar spectra and of the nebule. ore than a hundred photographs of spectra of stars have been-taken, and in the nebula of Orion details equal in faintness to stars of the 14:7 magnitude have been photographed. It when an exposure of 162 minutes was given, the tail impressed itself to an extent of nearly ten degrees in length. which would show the continuous spectrum of the nucleus and the banded spectrum of the coma. After an exposure 0 eighty-three minutes, a strong picture of the spectrum of the nucleus, coma and part of the tail was obtained, but the banded spectrum was overpowered by the continuous spectrum. I then applied the two-prism spectroscope used for stellar spectrum photography, anticipating that although the diminu- tion of light ae , serious after passing through the shit, two prisms and two object glasses, yet the advantage of being being more weakened than the banded by the increased disper sion the latter would become more distinct. ©. A. Young—sSpectroscopic Observations upon the Comet. 185 Three photographs of the comet’s spectrum have been taken with this arrangement with exposures of 180 minutes, 196 seen while the photography was in progress. It will take some time to reduce and discuss these photographs and pre- pare the auxiliary photographs which will be necessary for their interpretation. For the present it will suffice to say tha; the most striking feature is a heavy band above H which is divisible into lines, and in addition two faint bands, one be- tween G and / and another between / and was very careful to stop these exposures before dawn, fearing that the spectrum of daylight might. become superposed on the cometary spectrum. It would seem that these photographs aac ae the hypoth. esis of the presence of carbon in comets; but a series of com- parisons will be necessary, and it is not searubakte that a part of the spectrum may be due to other elements. 271 Madison Avenue, New York. ArT. XXV. ol eae Observations ae the Comet b, 1881 ; by Professor C. A. You WHILE the Comet was brightest the weather at Princeton was very tantalizing. From June 25 to July 3, the comet was seen and observed on every night except June 30, and on none of them, except July 2, more than an hour at a time, the work being invariably interrupted by clouds or fog. or the spectroscopic observations I have “used both the one- prism instrument, by the Clarks, which belongs with the Equa- torial, and the solar spectroscope by Gr ubb—the latter with di laps hark powers varying, according to occasion, from two to six dense glass prisms. e telescope was the 94 inch Equatorial. The following are the principal facts made out so far: — oo spectrum of the nucleus was found to cad We nie t simply continuous; but on several occasions, esp salty Tage 25, July 1, and July 12, it showed siatinee bande coinciding with those of the spectrum of the coma. When brightest the spectrum could easily be followed from the neigh- borhood of B to a. point well above G; and in the lower por- tion it showed color stron 2.) The spectrum of one ‘of the jets which issue from the nucleus was isolated on June 29th and found to be continuous. I think this was usually the case with the jets, but it is seldom possible to separate the spectrum of a jet from that of the nu- cleus sufficiently to be perfectly sure Am. Joor. nia” _ Vou. XX, No. 128,—Aueust, 1881. 186 ©. A. Young—Spectroscopic Observations upon the Comet. (3.) The spectrum of the tail appears to be a continuous spec- trum overlaid by a banded spectrum, the same as that of the coma. The bands in the spectrum of the tail were followed to a distance of about 20’ from the head, on June 29 and July 1. he continuous spectrum ceased to be visible before the bands were entirely lost sight of, using a slit wide enough to unite the b’s into one band. (4.) The spectrum of tne coma shows only three bright bands with a faint continuous spectrum connecting them. No other bands could be found, though the continuous spectrum could be followed from about half way between C and D, to above G. The Fraunhofer lines could not be seen either in the spectra of the nucleus or of the coma. While the comet was brightest, the bands, especially the up- per and lower ones, were very ill-defined, so much so as to in- terfere with satisfactory measurements of position. After July 1 the definition became better. .) The coma spectrum was very carefully compared with the spectrum of the Bunsen burner flame, with the spectra of Geissler tubes containing CO, CO, and ether vapor, and also with the Hae spectrum of magnesium and air. The wave length of the less refrangible edges of each of the three bands was carefully determined by micrometer measures, on June 29, d 12. spectrum and the spectra of the Geissler tubes was striking. The lower of the three comet bands was the only one which was even approximately coincident with any band of the tube spectrum. (6.) The measurements on the evenings named give the fol- lowing numbers for the wave-lengths of the bands, viz: Lower edge of lower band, A = 5629" + 40 Lower edge of middle band, A = 5164°9 + 0°6 Lower edge of upper band, = 4740° + 2°9 The lower band was much the most difficult to deal with. The maximum of brightness seems to be, not at the edge of the band, but a little way up, and this perhaps may explain the fact that I obtained 5564 in the case of Hartwig’s comet (while Von Konkoly obtained 5610—a much better result). Dr. Watts (Nature, vol. xx, page 28) gives 5634°7, 5165°3 and 4739°8 as the wave-lengths for the corresponding bands in the spectrum of the Bunsen flame. (7.) The middle band, on June 29, July 1, 2, and 38, showed — W. Harkness— Observations on Comet 6, 1881. 187 three fine, bright lines upon it, one just at the lower edge of the band, and the other two at distances of about 30 Angstrom units—coinciding apparently with three lines which are seen in the Bunsen flame spectrum, though I did not succeed in meas- uring them It is hiaedly necessary to say that the evidence as to the identity of the flame and comet spectra is almost overwhelming ; the peculiar i defined appearance of the cometary bands at the time of the comet’s greatest brightness is, however, something which I sales not yet succeeded in poiteine with the flame spectrum. The comet spectrum on July 25th certainly pre- sented a general appearance quite different from that of the later observations, as regards the definition of the bands. Perhaps I may be allowed to record here a fact which has nothing to do with the comet, but was observed while adjust- ing the a a ie upon the sun in preparation for evening ; that the one-prism spectroscope shows the bright lines in she upper portion of the chromosphere spectrum, above h, better than any other instrument I have yet tried. I have hitherto always found it rather difficult to exhibit the two H’s as bright lines to a person unused to the spectroscope, but with this instrument they are perfectly obvious—even = trusive. The only (and indispensable) precaution needed is to put the slit accurately in the focal plane of the telescope for these special rays, Princeton, July 14. T. XX VI.—WNote on the Observations 7 Comet b, 1881, segs vel ‘the United States Na val Observatory; by WM. HARKNE {Communicated by eres, 8 of Rear Admiral John Rodgers, U. S. N., Superintendent. | On the evening of June 28th, I examined the comet for polarization by means of a double image prism applied to the naked eye, and at first I fancied that when the two images were placed in the axis of the tail the one situated farthest forward was the fainter, but a careful examination by three different observers rendered this doubtful. Recourse was then had to a three-inch telescope armed with an eye-piece magnifying 34°5 diameters, and the image of the comet given by it was exam- ined, first with the double i image prism, and subsequentl Pe a Savart polariscope, but neither of these instruments s any polarization. Mr. Huggins thinks he has detected’ the 188 W. Harkness— Observations on Comet b, 1881, Fraunhofer lines in the continuous spectrum of the nucleus, and if this really is the case its light must be at least partly de- rived from the sun, and should show traces of polarization. As just stated, I failed to discern any with the double image prism ; but that is not a very delicate test, although, owing to the small size of the nucleus, it is almost the only one practicable. Un- der the magnifying power used the coma filled the field of view with bright light, and yet exhibited not a trace of polari- zation when tried by that most delicate of all tests, the Savart polariscope; thus apparently confirming the testimony of the ' spectroscope that the coma is self-luminous. On the evenings of June 28th, and July 1st and 2d, I exam- ined the spectrum of the comet with a spectroscope having a single sixty-degree prism through which a beam of light 0°82 of an inch in diameter is passed. The wave-lengths of the bands in the comet’s spectrum were determined by measuring the interval between them and the D line given by the flame of a spirit lamp with a salted wick held before the object glass of the telescope to which the spectroscope was attached; the measurement being effected by a micrometer which showed a bright point in the field of view. Owing to the unfavorable position of the comet, the only telescope upon which the spec- troscope could be used was my three inch of 48°6 inches focus, which is mounted upon a portable tripod stand, but is destitute of clamp and tangent screws. Notwithstanding the brightness of the comet, it gave a spec- trum very ill-defined, and difficult to measure. e spectrum of the nucleus seemed to be continuous, and its approximate extent was from D to G. I did not detect any Fraunhofer lines in it, but possibly they may exist and yet have been obliterated by the rather wide opening of the slit, which was 00125 of an inch. With a narrower slit it was difficult to keep the comet in the field of the spectroscope. The coma gave a spectrum consisting of three bright bands, so ill-defined that no precise measures of the wave-lengths of their edges could be made, but the wave-lengths of their brightest parts were respectively, 549°8, 512°4 and 467-2. This seems to be the ordinary comet spectrum. e measurement of the wave- length of the middle band is tolerably accurate, but the measurements of the other two are liable to considerable uncer- tainty, owing to the faintness of the bands. I estimated their relative brightness to be 5, 30 and 1. On July 1st a slight haziness of the atmosphere sufficed to render the third band in- visible. At a short distance from the head of the comet this band always faded out, and the spectrum of the tail seemed to consist of the first and second bands only—that is 549°3 and “4. made at the United States Naval Observatory. 139 On June 28th the comet’s nucleus was about as bright as a was perceptibly fainter, and its tail was only about eight de- grees long, but perhaps this was partly owing to the s00P five and a half days old, being above the horizon. On Jul 2d the atmosphere was very clear and the seeing good, but the visibil- ity of the comet was much diminished by the brightness of the moon, then near its first quarter. I estimated the length of the tail to be about the same as on the preceding evening, but Mr. ete thought he could trace it for rather more than twenty Since the 10th inst., Professor Hall has examined the comet with the twenty-six ine refractor, and Professor Hastman has examined it with the nine and six-tenth inch refractor, but neither of these gonnlanet have been able to see any indica- tions of a division of the The comet was Hist eae at its lower culmination, with the transit circle, on June 26, 27, 28, 29 and July 1, 2, 3, 5, 6, 10, 11. For the convenience of those who may cesire to compute the orbit, Professor Eastman has furnished from these observa- tions, the following pomene which are uncorrected for parallax and aberration time Washington Date. Right Ascension. Declination. June 26°5 Bh 48™ 385-04 +57° 40% 52"°0 July 1°5 6 22 46°85 70°39 OT '6 6 42 32°92 (aes