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JBRAHIES STANFORD UNIVERSITY LIBRARI

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The Brannpr Kpnlnmra] f.jhrary

u - C>i f^t-a^H^^e^

THE

AMERICAN

JOURNAL OF SCIENCE.

EDITORS

JAMES D. and E. S. DANA, and B. SILLIMAN.

ASSOCIATE EDITORS

Professors ASA GRAY, JOSIAH P. COOKE, and
JOHN TROWBRIDGE, of Cambridge,

Professors H. A. NEWTON and A. E. VERRILL, of

New Haven,

Professor GEORGE F. BARKER, of Philadelphia.

THIRD SERIES.

VOL. XXII. -[WHOLE NUMBER, CXXIIJ

Nos. 127—132.

JULY TO DECEMBER, 1881.

WITH SIX PLATES.

•

NEW HAVEN, CONN. : J. D. & E. S. DANA.

1881.

253581

TUTTLE, MOREHOUSE & TAYLOR, PRINTERS,
NEW HAVEN, CONN.

• • •
• • •

• • • •

• • • • •

• • • •

• •

CONTENTS OF VOLUME XXII.

NUMBER CXXVII.

Page

Abt. I. — Contributions to Meteorology; by Elias Loomis.

With Plate I, .---".-. 1

II. — Coal Dust as an element of danger in Mining ; by H. C.

Hovey, __ 18

III. — Notes on Mineral Localities in North Carolina; by W.

E. Hidden, _ 21

IV. — Variation in Length of a Zinc Bar at the same Temper-
ature ; by C. B. Comstock, 26

V. — Restoration of Dinoceras mirabile; by O. C. Marsh.

With Plate II, 31

VI. — Torbanite or "Kerosene Shale" of New South Wales;

by A. Liversidge, 32

VII. — Meteorological Researches, Part II. Cyclones, Torna-
does and Waterspouts ; by W. Ferrel, 33

VIII. — Magnetic Observations made in Davis Strait, in

August and September, 1880; by O. T. Sherman, 49

IX. — Crystalline form of Sipylite; by J. W. Mallet, 52

X. — Observations on the Structure of Dictyophyton and its

affinities with certain Sponges ; by R. P. Whitfield, . . 53

XI. — Carboniferous Rocks of Southeast Kansas; by G. C.

Broadhead, . _ . _ _ _ 55

XII. — Later Tertiary of the Gulf of Mexico; by E.W. Hilgard.

With a map (Plate III), _ 58

XIII. — Dufrenite from Rockbridge County, Va. ; by J. L.

Campbell, _ . . _ 65

XIV. — Turquois of New Mexico ; by B. Silliman, 67

SCIENTIFIC INTELLIGENCE.

Chemistry and Physics. — Free Fluorine in Fluor Spar, Loew: Arsenobenzene,
Michaelis and Schcltze, 71. — Transformation of Dextrose into Dextrine,
Musculus and Meyer, 72. — Pentathionic Acid, Lewes: Photographies, E L.
Wilson, 73. — Conservation of Electricity, M. G. Lippmann: Inverse Electromo-
tive force of the Voltaic arc, 74. — Stellar Photography, H. Draper: Weather
Warnings, B. Stewart: Storing of Electricity, M. Faure, 75.

IV CONTENTS.

Geology ond Xatnral History. — Oeology of British Columbia. G. M. Dawsox. 75. —
Caribbean Miocene fossils: G*oiogical Surrey of New Jersey for 1880. 77. —
Geological Surrey of Pennsylvania : «;eol<^gy of the Oil Regions of Warren,
Venango. Clarion and Butler Counties. Pa., by J. F. Carll: Statistics and
Geology of Indiana for 1SS0: Illustrations of the Earth's Surface. N. S. Shaler
and W. M. Davis. 7S.— The Trilobite. C. D. Walcott. 79.— Geological Survey
of Alabama. E. A. Smith : Felsites and their associated rocks north of Boston,
J. S. Dilleb: Memoire sur les Phenomenes d* A Iteration des Depots superficiels,
E. Van den Bboeck : Application of a solution of mercuric potassium iodide in
mineralogical and lithological investigations. V. GoLDSCHXiDr. SO. — Deer horns
impregnated with tin ore. J. H. Collins. 31. — Microlite from Amelia County.
Virginia: Mya arenaria: Rhizopods. the food of some young fishes. 82.

Astronomy. — Figures of the planets. 82. — Observations of the Transit of Venus,
S. Newcomb : Observations of Double Stars made at the U. S. Naval Observa-
tory, A. Hall, 84.

Miscellaneous Scientific Intelligence. — Historical Sketch of the Boston Society of
Natural History, T. T. Bouve. 85. — American Association at Cincinnati: On
the so-called Cosmical Dust, Lasaulx, 86.

NUMBER CXXVIIL

Page

Art. XV. — Modification of Wheatstone's Microphone and its

applicability to Radiophonic Researches ; by A. G. Bell, 87

XVI. — Method of obtaining and measuring very high Vacua

with a modified form of Sprengel-pump ; by O. X. Rood, 90

XIX. — Geological Relations of the Limestone Belts of West-
chester County, New York : Origin of the Rocks of the
Cortlandt Series ; by J. D. Dasa, __ _. 103

XX. — New Meteoric Iron, of unknown locality, in the Smith-
sonian Museum ; by C. U. Shepard, 119

XXI. — The relative motion of the Earth and of the Luminif-

erous Ether ; by A. A. Michelsox, 120

XXII. — Observations on the Light of Telescopes used as

Night-Glasses ; by Edward S. Holdex, 129

XXIII. — Nature of Dictyophyton ; by R. P. Whitfield, .. 132

XXIV. — Photographs of the Spectrum of the Comet of June,

1881 ; by Henry Draper, 134

XXV. — Spectroscopic Observations upon the Comet 6, 1881 ;

by C. A. Young, _ 135

XXVI. — Observations of Comet b, 1881, made at the United

States Naval Observatory; by Wm. IIarkness, 137

XXVII. — Observations on the Comet 1881 b; by Lewis Boss, 140

XXVIII.— Polarization of Light from Comet b, 1881 ; bv A.

W. Wright, ../.... 142

SCIKNTIFIC INTELLIGENCE

Chemistry and Physics. — Ozone as a cause of the Luminosity of Phosphorus,
Chappuis: Appearance of Nitrous Acid during the Evaporation of Water,
Warington, 145. — Boron hydride, Jones and Taylor: Purification of Carbon
Disulphide, Allary: Electric Absorption of Crystals, H. A. Rowland and
E. H. Nichols, 147. — Transmission of radiation of low refrangibility through
Ebonite, Abney and Festing : Conservation of Electricity, Lippmann : Heating
of Ice, Wullnbe: Atomic weight of Cadmium, Huntington, 148.

CONTENTS. V

Geology and Mineralogy. — Terraces and Ancient Coast lines (" Strandlinien ").
Karl Pettersen, 149.— Substances obtained from some "Forts vitrifieV' in
France, M. Daubree, 150. — Pre-glacial Outlet of the Basin of Lake Erie, J. W.
Spencer, 151. — Laccoliths (or Laccolites) in Japan, G-. H. Kinahan: Iron Ore
of Iron Mine Hill, Cumberland, R. I.: Brazos Coal-field, Texas : Report of the
Geological Survey of Pennsylvania, F. Platt and J. P. Wetherell, 152. — Land-
plants in the Middle Silurian of North Wales, H. Hicks: Vertebrata of the Per-
mian Formation of Texas, E. D. Cope: Life- History of Spirifer laevis, II. S.
Williams: Geological Society of London: Optical Characters and Crystalline
System of some important Minerals, 153. — Notices of new minerals, 255. —
Dawsonite from Tuscany : Vanadium Minerals from Cordoba : Zinn, eine geol-
ogisch-montanistisch-historische Monografie, E. Reyer, 157.

Botany and Zoology. — Marine Alga? of New England, W. G. Farlow, 1 58. — Das
System der Medusen von E. Haeckel, 160. — Reptiles and Fishes in the Museum
of Comp. Zoology, S. Garman : Dredging along the Atlantic Coast of U S. by
Steamer Blake, 162. — Perissodactyles, with note on Toxodon, E. D. Cope, 163.

Astronomy. — Photographic Spectrum of Comet 1881, 6, W. Huggins: Notice of the
Comet, C. E. Burton, 163. — Observations on the Comet, W. H. M. Christie, 164.

Miscellaneous Scientific Intelligence. — International Polar Stations occupied by the
Signal Service, 164. — Smithsonian Institution: Endowment of the American
Chemical Society, 165. — J. Lawrence Smith's Collection of Minerals and Meteor-
ites, 1 66. Obituary— Achille Delesse : Deville, 1 66.

NUMBER CXXIX.

Page

A rt. XXIX. — Benjamin Peirce, _ _ _ . 167

XXX. — Emerald-green Spodumene from Alexander County,

North Carolina ; by E. S. Dana, . _ 179

XXXI. — Objects and Interpretation of Soil Analyses; by

E. W. HlLGARD, _ _ _ _ 183

XXXIL— Mineralogical Notes; by B. Silliman, 198

XXXIII. — Liquefaction and Cold produced by the mutual

reaction of Solid Substances; by Evelyn M. Walton,. 206
XXXIV. — Spectrum of Arsenic ; by Oliver W. Huntington.

With Plate IV, 214

SCIENTIFIC INTELLIG P]NCE.

Chemistry and Physics. — Spontaneous Oxidation of Mercury and other Metals,
Bebthelot, 217. — Hesperidin, a Glucoside of the Aurantiacese, Tiemann and
Well, 218. — New series of Volatile Organic Bases, Meyer and Trradwell:
Photometry of the Fraunhofer lines, Vierordt: Intensity of Sound, Overbeck,
219. — Reversal of the lines of Metallic Vapors, Liveing and Dewar: Change
of State, Poynting, 220.

Geology and Mineralogy. — Geology of the Province of Minas Geraes, 221. — Prog-
ress of the Eruption on Hawaii, 226. — Glacial drift on Mt. Ktaadn, Maine,
C. E. Hamlin, 229. — Doleryte (trap) of the Triassico-Jurassic area of Eastern
North America, G. W. Hawes, 230. — New Devonian Plants, J. W. Dawson : Fos-
sil Plants from the Lignite Tertiary Formation, at Roches Percees, Sonris River,
Manitoba, J. W. Dawson, 233. — North American Mesozoic and Caenozoic Geol-
ogy and Palaeontology, S. A. Miller : Species of Pterygotus from the Water-
lime group near Buffalo, J. Pohlman, 234. — Genus Alveolites, Amplexus and
Zaphrentis, from the Carboniferous System of Scotland, J. Thomson: Memoir
upon Loxolophodon and Uintatherium, H. F. Osborn: Vanadinite in Arizona,
W. P. Blake, 235.

V! CONTESTS.

BvUniy awl Zoology. — Monographic Pluenogamarum. DeCaxdolle. 235. — Arbo-
retum Segrezianum, A. Lavallee. 238. — British Moss-Flora. R. Bbaithwaite:
Butterflies, their Structure, Changes and Life-histories, S. H. Scudder. 239.

MissceOaneous Scientific Intelligence. — Meeting of the American Association for the
Advancement of Science, at Cincinnati. Ohio. 240. — Science Observer and a
cipher-code for Astronomical telegraphic messages, 244. — A Dictionary of the
Exact Sciences, Biographical and Literary, J. C. Poggendorff : Report of the
Cotton Production of the State of Louisiana, E. W. Hilgard, 245. — Third
Bressa Prize, Academy of Turin, open to Scientists and Inventors of all Na-
tions. 246.

NUMBER CXXX.

Page

Art. XXXV. — Cause of the Arid Climate of the Western por-
tion of theiUnited States ; by C. E. Duttcxs, 247

XXXVI. — Embryouic forms of Trilobites from the Primor-
dial Rocks of Troy, X. Y. ; by S. W. Ford, 250

XXXVII. — Observations of Comet b, 1881 ; by E. S. Holden, 260
XXXVIII. — Thickness of the Ice-sheet at any Latitude ; by

W. J. McGee, 264

XXXIX. — Address of Sir John Lubbock, 268

XL. — Notes on Earthquakes ; by C. G. Rockwood, 289

XLI. — Marine Fauna occupying the outer banks off the

Southern coast of New England; by A. E. Verriix, 292

XLII. — Note ou the Tail of Comet 5, 1881 ; by Lewis Boss.

With Plates V and VI, 303

XLIQ, XLIV. — Geological Relations of the Limestone Belts

of Westchester Co., New York ; by James D. Daxa, 313, 327

SCIENTIFIC INTELLIGENCE.

Chemistry and Physics. — Velocity of Light, Raleigh : Movement of Sound Waves
in Organ Pipes, R. Koznig: Conductivity of Metals for Heat and Electricity,
Lorenz. 316. — Microphonic action of Selenium cells, J. Moser: Stresses caused
in the Interior of the Earth by the Weight of Continents and Mountains, G. H.
Darwin. 317.— Expansion of Cast Iron while solidifying. M. J. B. Hannay and
R. Anderson. 320.

Geology and Xatural History. — Origin of the Iron Ores of the Marquette District,
Lake Superior, M. E. Wadsworth. 320. — Taconic rocks of the border of Lake
Champlain. J Marcou, 321. — Volcanic Eruption on Hawaii: Glacier Scratches
in Goshen in Northwestern Connecticut: Structure and Affinities of the Genus
Monticulipora and its Subgenera, H. A. Nicholson. 322. — Ulexite in Califor-
nia. W. P. Blake: Worked Shells in New England Shell- Heaps, E. S. Morse:
Changes in Mya and Lunatia since the deposition of the New England Shell-
Heaps, E. S. Morse, 323. — Beitrage zur Morphologie und Physiologic der Pilze,

* Vierte Reihe, A. DeBary and M. Woronin, 324. — Fauna und Flora des Golfea
von Neapel, Solms-Laubach. 325. — Botanical Collector's Handbook, W. W.
Bailey. 326.

Miscellaneous Scientific Intelligence. — Ancient Japanese Bronze Bells, E. S. Morse,
326.

CONTENTS. * Vll

NUMBER CXXXI.

Page

Abt. XLV. — Jurassic Birds and their Allies; by O. C. Marsh 337
XLVI. — The remarkable Aurora of September 12-13, 1881 ;

by J. M. SCHAEBERLE 341

XLVIL— Address of Sir John Lubbock 343

X17VII bis. — The Stereoscope, and Vision by Optic Diver-
gence ; by W. LeConte Stevens 358

XXi VIII. — The Electrical Resistance and the Coefficient of

Expansion of Incandescent Platinum ; by E. L. Nichols 363

XLIX. — Local Subsidence produced by an Ice-sheet ; by W.

J. McGee _ 368

L. — Note on the Laramie Group of Southern New Mexico ;

by J. J. Stevenson 370

LI. — folariscopic Observations of Comet c, 1881 ; by A. W.

Weight . _ 1 372

LH. — The Relative Accuracy of different methods of deter-
mining the Solar Parallax ; by W. Harkness 375

LIII. — The Nature of Cyathophycus; by C. I). Walcott .. 394

SCIENTIFIC INTELLIGENCE

Chemistry and Physics. — International Congress of Klectriciaus, 395. — Elasticity
and Motion, W. Thomson: Efficiency of Spectroscopes, Lippich, 396. — Niagara
Falls as a source of Energy, W. Thomson: Change of plane of polarization of
Heat rays by Electro-magnetism, L. Grunmach, 397. — Electro-dynamic Balance,
H. Helmholtz: Change of thermo-electric condition of iron and steel by
magnetization, V. Strouhal and C. Barus: Principles of Chemical Philosophy,
J. P. Cooke: A Manual of Sugar Analysis, J. II. Tucker, 398.

Geology and Mineralogy. — Geology and Resources of the Black Hills of Dakota,
H. Newton and W. P. Jenney, 399.— Primitive Industry, or Illustrations of
the Handiwork in stone, bone and clay of the Native Races of the Northern
Atlantic Seaboard of America, C. S. Abbott, 401. — M. E. Wadsworth on
the Iron Ores of the Marquette District, 402. — Jasper and Iron Ores of the
Marquette Region, M. E. Wadsworth, 403. — Saurian and Mammals of the
Lowest Eocene of New Mexico: Miocene Rodents of North America and Cani-
dss of the Loup Fork Epoch: The Irish Elk, Megaceros Hibernicus, in the
Ancient lake deposits of Ireland, W. Williams, 408. — Tertiary Lake Basin of
Florissant, Colorado, S. H. Scudder, 409. — Address of the President of the
Geological Society of London: Pantotheria of Marsh: Vanadates of Lead at
the Castle Dome Mines in Arizona, W. P. Blake, 410.

Botany and Zoology. — Recent Papers on the Marine Invertebrata of the Atlantic
Coast of North America, A. E. Verrill, 411. — Manual of Practical and Normal
Histology, T. M. Prudden, 414. — U. S. Entomological Commission : The Hes-
sian Fly, A. S. Packard: E. S. Morse on changes in Mya and Lunatia, 415.

Astronomy. — Theory of the Moon's motion, deduced from the Law of Universal
Gravitation, J. N. Stockwell, 415. — Astronomical and Meteorological Obser-
vations made during the year 1876 at the LT. S. Naval Observatory, 416.

Obituary. — Dr. G. Linnarsson, 416.

VU1 CONTENTS.

NUMBER CXXXII.

Page

Art. LIV. — On a possible cause of the Variations observed

in the amount of Oxygen in the Air; by E. W. Morley 417

LV. — On Jolly's Hypothesis as to the Cause of the Varia-
tions in the Proportion of Oxygen in the Atmosphere ;
E. W. Morley _ 42.^

LVT. — Lower Silurian Fossils in Northern Maine; by W.

W. Dodge _ _ 4^

LVII. — A Contribution to CrolPs Theory of Secular Climatal
Changes ; by W. J. McGee _ _ _ . _ 4

LVIH. — The Stereoscope, and Vision by Optic Divergence ;
by W. LeC. Stevens _ 4

LIX. — On the relation of the so-called "Karnes" of the
Connecticut River Valley to the Terrace-formation ; by
J. D. Dana 4*

LX. — Japanese Seismology ; by C. G. Rookwood 4(* ^

LXT. — An Apparatus for the Distillation of Mercury in

Vacuo ; by A. W. Wright 479

SCIENTIFIC INTELLIGENCE.

Physics and Astronomy. — Dynamo Electric Machines, W. Thomson : Rotation of
plane of Polarization of Light by the Earth's Magnetism, II. Becquerel : The
value of the Ohm, Rayleigh and Schuster, 484. — Ephemeris of the Satellites
of Mars, 71. S. Pritohett, 485.

Geology and Natural History. — Geological Survey of Pennsylvania, 485. — First
Annual Report of the U. S. Geological Survey, C. Kino : The Kames of Maine,
G. H. Stone, 487. — Geology of Staten Island, N. L. Britton: Apuan Alps, B.
Lotti and D. Zacoagna, 488. — Jelly-like carbonaceous mineral resembling dop-
plerite, from Scranton, Penn., T. Cooper: Emeralds from Alexander County,
North Carolina, "W. E. Hidden, 489. — Brief notices of some recently described
minerals, 490. — Artificial formation of the Potash-feldspar, Orthoclase, C. Erie-
del and E. Sarasin: English Plant-names from the Tenth to the Fifteenth
Century, J. Earle. 491. — Familien Podostemaceae, E. Warming: Recherches
sur la physiologie et la morphologie des ferments alcooliques, E. C. Hansen,
492. — On an Organism which penetrates and excavates Siliceous Sponge-
spicules. P. M. Duncm n. 493. — Bulletin of the Museum of Comparative Zoology
at Harvard College: The Palseocrinoidea, Wachsmuth and Springer: Cosmos
les Mondes, 494.

Index to vol. xxii, 495.

ERRATA.

P. 186, 3d line from top, for "type are" read "type, are."
P. 187, 5th line from bottom, for "effected" read "affected."
P. 188, 12th lino from bottom, after " Adolph Mayer" the sentence should be
continuous; thus "Adolph Mayer, I find, etc."

P. 191, 7th line from top, for "clay, permeating" read "clay, but permeating."
P. 191, for "differing so in" read " differing in."

P. 192, 11th line from top, for "proportionately" read "proportionality."
P. 240, 4th line from bottom, for Capt. W. H. Dow, read Prof. W. H. Dall.
P. 286, 19th line from bottom, for " Prototheria " read " Pantotheria."

' X

THE

AMERICAN JOURNAL OF SCIENCE.

[THIRD SERIES.]

-*♦♦-

Art. I. — Contributions to Meteorology : being results derived from
an examination of the observations of the United States Signal
Service, and from other sources ; by Elias Loomis, 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 sea4evel of barometric observations made at elevated

stations.

During the past eight years a large 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 paper a storm
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 bar-
ometric observations made on Mt. Washington. I first pre-
Eared a table showing the reduction to sea-level, according to
>unwoody's Tables (S. S. Report for 1876, p. 354), for the entire

Am. Jour. Sol— Third Series, Vol. XXII, No. 127.— July, 1881.

2 # E. Ifiomis — Contributions to Meteorology.

• • • • •

• • Ifcngtf of 'temperattfrt and pressure experienced on Mt Wash-
ington. I next computed the reduction according to the for-
mula of Laplace, as developed in Guyot's Tables published by
the Smithsonian Institution (Guyots Meteorological Tables,
series D, page 33), taking account of all the minute corrections.
I next computed the reduction according to the formula of
Plan tarn our, as developed in the Tables of Colonel Williamson
(Professional Papers of the Corps of Engineers, No. 15). In
order to compare these Tables with the actual observations, I
took the monthly averages for Mt Washington, as published in
the Annual Reports of the S. S. for eight years (1872-1879) ;
subtracted 6*36 inches for each month, and the remainder was
regarded as the mean observed height I took the mean be-
tween the reduced heights at Burlington, Vt and Portland, Me.,
and used the result as representing the height of the barome-
ter at sea-level under Mt Washington. The difference be-
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 and
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 040 inch below its normal height;
4. All the dates on which the barometer at either of the sta-
tions rose 0*d0 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 observations)
was determined; the mean pressure at Burlington and Port-
land, and also the mean temperature at Burlington and Port-
land. These results enabled me to extend the observed reduc-

E. Loomis — Contributions to Meteorology. 8

tion to sea-level from the barometric height 22*7 inches to 24*2
inches and from the temperature —10° to 4-65°. In order to
smooth down the inequalities of the observed numbers, I toot
the mean between each three consecutive numbers correspond-
ing to the same temperature, nnd substituted this result for the
middle number. It is presumed that the results thus obtained
represent pretty nearly the results which would be obtained
from observations extending over a long term of years.

The results thus described are exhibited in the following
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 table,
and the mean temperature of the air column from —10° to
+65° is given on the left margin. Corresponding to each tem-
perature given in the table are four horizontal lines, the first
of which (marked D), gives the reduction to sea-level as com-
puted from Dunwoody*s Tables; the second horizontal line
(marked L), shows the reduction computed from Guyot's Ta-
bles founded on the formula of Laplace ; the third horizontal
line (marked P), shows the reduction computed from William-
son's Tables, which are based on those of Plantamour; the
fourth horizontal line (marked 0), shows the reduction deduced
from actual observations as above described.*

An examination of this table shows the following results:
1. Dun woody's Tables accord very well with those derived from
the formula of Laplace, the differences ranging from 4-0*011
inch to —0*041 inch.

2. The differences between the formulas of Laplace and
Plantamour range from 4-0*030 inch to 4-0*103 inch, the reduc-
tion by Laplace being on an average 0*053 inch greater than
by Plantamour.

3. The reductions deduced from the actual observations dif-
fer very much from either of the values above computed ; the
differences from Laplace ranging from 4-0*263 to —0*105 inch.
These differences follow a remarkable law. According 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 -2*5- part of its former value. Observations, how-
ever, 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 was written I have been informed that the constant 6*36
inches for reducing the Mt. Washington observations to sea-level began to be used
March 1st, 1874, and that for the two preceding years the constant 6*31 inches
had been used. Thus it appears that for a period of eighteen months, I had made
the Mt. Washington barometric observations too low by 0*05 inch, which would
indicate an average error of about 002 inch for the entire period of the observa-
tions. This would correspond to an average error of about 0*001 inch in the col-
umn of observed reductions to sea-level, which is so small an error that I have
not considered it necessary to re-compute the entire series of observations.

4 K Loomis — Coitt-rihutir.ins to Hfdcorohyi/.

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M Loomis—* Contributions to Meteorology. 5

as that given by the formula of Laplace. The influence of
temperature on the reduction to sea-level, as deduced from the
observations, differs but little from that given by the formula
of Laplace. At the highest temperatures, the observed reduc-
tion accords with that computed by the formula when the pres-
sure at sea-level is 29*8 incnes ; 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-level for Mt. Washington depends mainly
upon temperature.

The observed values 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 rigorously 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 observ-
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

-7 1; column 5th

shows the observed reduction to sea-level I — - — — 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 3 and 4 ; column 7th shows the reduction ac-
cording to the table on p. 4, in the lines marked 0 ; column 8th
shows the difference between the numbers in columns 5 and 6 ;
column 9th shows the difference between the numbers in columns
5 and 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 & Loorais — Contributions to Meteorology.

Cases in which the reduction to sea-level teas unusually great.

Date

Brt.to.~feT.

«*«"

fa.

W.Wtata.

Ko.

Ob..

L»H

T«Ur

UK.

Obi.

Wind.

1872 Nov

7.3

2 2 -7M

30°-2

6-4B

819

t:-4.i

0-30

«8

* N.W. 65

31-2

6-54

6-18

6-40

-36

8 N.W. 48

8.2

34-2

iMfi

6-18

6-36

■31

•14

N\ 65

23-12

2[i-7

e-66

6-29

i;-i 2

■36

N.W. 58

9.2

-li

29-7

6-66

6-32

6-43

-33

W. 78

29.2

22-89

220

t.VSI

(!■;-.::

■46

-28

S.W. 35

30.1

-63

1,1-2

('.■HI

6-47

6'72

-34

-09

N.E. 45

•\-w.<

'.7 -r. 1

6-73

■38

-16

W. 48

Dee.

-85

12-6

ij-wi

6-50

■49

-31

■1

N. 52

3.!

23- M

6-66

6-48

•18

S.E. 60

-24

21-7

li-TN

615

u-;>D

-33

-28

W. 58

10.1

22'78

7-2

6-87

(1-717

-:u.>

W. 59

15.2

23-13

20-0

5-82

8-46

S-67

-37

■ss

N. 68

23.2

- 1-2

7-13

+;■:>;.

W. 43

24.3

-05

-130

7 1-!

7-00

7-22

'44

■33

W. 44

38.1

22-76

— 10-7

7-21

6*89

■32

N.K. 60

1873 Jan.

23-11

15-0

6 -96

6-54

6-64

-42

■32

W. 60

11.3

7-10

6-80

6-05

-30

N". 76

29.1

■10

- 2-2

7-14

t3-83

697

■3]

-17

W. 54

Feb.

10.1

22-96

— 2-6

T-ie

6'80

6-96

-38

-32

N.W. 77

1 0.3

23-01

0-7

7-08

6-75

6-89

•19

N.W. 103

March 16-2

22'78

•21-T

6'fl7

6-32

e-&4

■35

-13

W. 28

16.3

■74

17-2

S-fiS

639

6-61

■v>

-27

1.1

N.W. 56

17.1

•87

14-2

6'95

6-47

665

-48

•30

W. 56

17.2

23-16

1T-7

6-81

6-49

rfi-SO

■32

-21

N.W. 25

24.1

22-92

707

6-60

6-76

■47

-31

W. 48

Dec.

10.1

23-33

23-7

6-T8

6-44

6-63

■34

-26

jr.w. 62

1874 April

30.2

22-6T

23-2

6-72

628

•J-Bl

"31

x.vr, t3o

30.3

■73

23-5

6-30

6-61

'40

-19

N.W. 115

Dec.

29-2

23-02

11-2

6-88

6-58

610

-IS

N.W. 80

30.2

■01

- 6-2

7-22

6-87

7-ft3

N.W. 98

l.s

1875 Jan.

9-3

22-70

- 8-7

7-26

685

7-10

-41

■18

V.W. 11)0

14.1

12-0

6'39

6-64

6-68

-36

-30

V.W. 70

11.3

,'82

- 4-0

7-13

6-80

6-99

-33

■14

N.W. —

«•

16.1

-71

— 16-5

7-42

7-39

■44

N.W. —

16-2

■95

-10'2

7-2£

•30

-11

V.W. —

15.3

23-00

T-24

7-09

■32

■15

N.W. —

22-91

-11-3

7-28

6-96

7-1B

■32

-10

N.W. —

aii

25-2

130

6-91

6-53

;■■„■)

■;■.«

-23

r.w. so

31 1

26.2

•96

<j-(J

7-14

(j-;-;

;;>!

-at

2::

SLW. 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. ; 1.6 occurred at the
4.35 P. 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

K Loomis — ContribiUions to Meteorology. 7

these cases the observed redaction was greater than that com-
puted from the Laplace formula. There is 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 8th is 0*662 inch, and the
mean of the numbers in column 9th is 0*190 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,
exceeds 0*3 inch. This table is therefore a great improvement
upon Laplace and also upon any other table of reductions hith-
erto published.

All these cases enumerated on page 6 occurred during the
progress of storms which were generally of considerable vio-
lenca In every case, the barometric minimum on Mt Wash-
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 passed
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. Washington, and in other cases the differ-
ence of temperature was very small. In 1873, Jan. 29.1, the
thermometer at Burlington was 9° lower than on Mt Washing-
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 decided effect upon
the pressure at the summit of Mt. Washington.

It will also be observed that in half of these cases 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, therefore,

8 H 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
weather maps which show the isobars for the Atlantic Ocean
since March, 1874, assist us in understanding the cause of these
high winds on Mt. Washington. They show that an area of
low pressure prevailed on the east side of the mountain, gener-
ally near Nova Scotia or Newfoundland; and the winds on
Mt Washington were controlled by this low area long after the
high winds at Burlington and Portland had subsided.

We thus find that if the barometric observations on Mt
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, I
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, 1873, to January, 1875, and from Janiiary, 1877, to
July, 1877 (22 months), and the monthly means from November,
1873, to June, 1879, published in the annual reports of the Sig-
nal Service. These materials were reduced in the manner
already described in the case of Mt Washington. The table
on page 9 shows the reduction from Pike's Peak to Denver
for a range of the barometer from 17*1 inches to 18*2 inches on
Pike's Peak, and for a mean temperature of the air-column
between the two stations from —10° to +60°. Corresponding
to each temperature are two horizontal lines, one of which is
marked L, showing the reduction computed from Guyot's
Tables based on the formula of- Laplace (Guyot's Met. Tables,
series D, p. 33), and the other, marked O, shows the reduction
deduced irom actual observations.

We see from this table that the increase in the value of the
reduction to sea-level resulting from an increase of pressure on
Pike's Peak is very small, being, on an average, less than one-
fifth of that computed from the formula of Laplace. In this
particular the results accord very closely with those before
found for Mt Washington. The influence of temperature

K Loomis — Contributions to Meteorology.

upon the amount of the reduction differs somewhat from that
given by the formula. While the pressure at Pike's Peak re-
mains unchanged, the observed change in the reduction to Den-
ver, resulting from a change of temperature, is 33 per cent less
than the computed reduction. At the highest temperatures
the observed reduction accords with that computed by the for-
mula when the barometer at Denver stands at 24*95 inches;
and at the lowest temperatures the agreement occurs when the
barometer at Denver stands at 2445 inches.

Reduction of barometer from Pike's Peak {elevation 14,056 feet)

to Denver {elevation 5,262 feet).

Therm.

L
O

L
0

L
O

L
0

L
O

17-1.

17-2.

17-8.

17-4.

17-5.

17-6.

177.

178.

17-9.

18-0.

18-1.

18*2.

— 10°

7*651
7 565

7-696
7*572

7-741

7-786

7*830

7*875

7*920

7-965

8-010

8-055

8100

8-145

— 5

7-540
7*511

7-584
7-517

7-628
7-523

7-673

7-717

7-806

7*850

T-894

7-938

7*982

8027

7-433
7*436

7-477
7-440

7-520
7-442

7*564
7-442

7-607
7 445

7-651

7-694

7-738

7*781

7*825

7-868

7-912

+ 5

7-329
7*353

7-372
7*359

7*415
7-363

7-458
7-364

7-501
7-364

7-544
7*364

7.586

7*629

7-672

7-715

7-758

7*801

7-227
7-278

7-269
7-284

7-312
7-291

7-354
7-291

7-396
7-291

7-439
7-290

7-481
7-289

7*523

7-287

7-566

7-608

7*651

7-693

7128
7-212

7-170
7-216

7073
7-12o

7-212
7-218

7-253
7-223

7-295
7*228

7-337

7-228

7-378
7-228

7-279
7-186

7-420

7-228

7-462

7-504

7-546

7-588

7032

7-114
7*155

7-155
7-170

7-197
7-177

7-238
7-180

7-320
7-188

7-361

7-402

7*443

7-485

6-938

6-979

7-019
7-087

67927"

7-060
7-102

7*101
7-120

7-: 41
7126

•ToiT

7-064

7*182
7-127

7-088
7*067

7-222
7-130

7-263
7-133

7*303

7-344

7-385

6-847

6*887

6-967
7-033

7007
7 043

7*128
7-070

7168
7076

7-208

7-248

7-288

6-758

6-798

6-837

6-877
6968

6*916
6-976

6*956
6-993

6-995
7010

6¥05"
6-939

7035
7-017

7-074
7030

7114
7036

7153

7193

6-671

6-710

6-749

6-788

6-827
6-914

6*866
6-930

6-944
6-957

6-983
6-972-

6-895
6-908

7-023
6-980

7062

7-101

6-587

6-626

6664

6-703

6*741

6-780
6-860

6-818
6-867

6-857
6-884

6777T
6-809

6-688
6-754

6934
6-920

6*972

7*011

6-505

6*543

6-581

6*619

6-657

6-695 ,6-733

'6-797

6-809
6-842

6-772

6*848
6-857

6-886
6860

6*924

6*425

6-463

6500

6-538

6575

6613

6-650
F569"

6-763
6-795

6-801
6-802

6-718"
6-744

6-838

6-346

6-383

6*420

6457

6-494

6-532

6-606

6-643
6*733

6-680
6-738

6-755
6-750

In order to test the preceding results under different circum-
stances I selected two stations near the Pacific coast, viz : Sac-
ramento and Summit. Sacramento is situated in lat. 38° 35',
long. 121° 31', and is elevated 31 feet above the sea. Summit
is situated on the Central Pacific Eailroad in lat. 39° 20', long.

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 Survey
of California under the direction of Prof. Josiah D. Whitney.
The monthly means of the barometer and thermometer were
published by Pro! 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 — 1. 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 eaxsh
day. These 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 temperature should be
some multiple of five. The observations of each of these
classes were then compared in respect to barometric pressure
at Summit, so that all those observations which were made at
nearly the same pressure were grouped together, and an aver-
age was taken of the numbers in each of these groups. In this
way I obtained the reduction to Sacramento corresponding to a
considerable range of temperature and pressure. The inequal-
ities of the resulting numbers were somewhat smoothed down
by applying the method described on page 3. The final re-
sults are given in the table on pa^e 11 which shows the reduc-
tion of the barometer from Summit to Sacramento for pressures
ranging from 22*7 to 23 6 inches; and for temperatures of the
air-column from Summit to Sacramento ranging from 25° to
80° F. Corresponding to each temperature are given two hori-
zontal lines marked L and 0 ; the former shows the reduction
computed from the formula of Laplace, the latter shows the
reduction deduced from the actual observations.

An examination of this table shows that the reduction of the
barometer from Summit to Sacramento instead of increasing
with an increase of pressure, as required by the formula of
Laplace, invariably decreases; and the average observed de-
crease is seven-eighths of the increase computed from the for-
mula; and for all temperatures above 40° the observations
show a decrease in the amount of the reduction fully equal to
the increase computed from the formula. This 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
the atmosphere is greatly disturbed. While the pressure at

E. Loomis — Contributions to Meteorology.

Summit remains unchanged, the observed change in the reduc-
tion to Sacramento resulting from a change of temperature is
41 per cent less than that computed from the formula ; but at
all temperatures the observed reduction accords nearly with
that computed from the formula when the barometer at Sacra-
mento stands at 29 9 inches.

Reduction of barometer from Summit {elevation 7,017 feet)
to Sacramento {elevation 31 feet).

-1 ■

Vft.

W8.

JW.

at j a-i. 1 »i. | w-s. 1 »•.

»f. |«K

9B°

L
O

■. na .

; ,-*<

7 11!

71&0|1*1HI|7 212 3 VI i 7 r. 1

1-306 7 '336

., ••.;

■ •■■■j:

1 2131 243

L
0

6-981

6916

6-940

7122 1152

6794

6824,6:B*4J6,S»4j61<J4 CS44 £374 1«U

I 088 1 063

L
O

81 1 1

6 HU

.;-■..-...,■ .. .-.-■..-■.

6-941 6-an

. r.r.

■. I,..-.

6-688

S-M66AMO 6765 ■•ISlltW

' :>i:>

.-. BTS

s-eoi

■■ess

6 052 Ii r.if, 6 flfis G 075

:-; ■ -id

L
0

:t--2

; Si: :

u .-..':.

;:.--

: ■ '■:.■'

■ i:

G 4:.-.

; r.i

; i".'

6-610.6-638 ■ ■

iVoi ""

("i
L

0
L

<■•

6-323

6-251

;■;;;-,[

:-:;-,:>

;■ -■

. 1 :; .. |..v- (-.-■■. .:-

6*46 8 514

6278

6-300

- ::j >i 4u:i

i-l»«.

J-J01 6-23-1

;- ■-

rt'2«9|6-3Jf>6-H4HjG371

I 388 fi 426

6366,

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 slation
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 observations are published in
the Bibliotheque Universelle de Geneve, and I have employed
the observations of three years, viz : 1877, 8 and 9. The mode
of reducing the observations was similar to that described on
page 10. The results are shown in the table on page 12 which
exhibits the reduction computed by the Laplace formula from
Delcros' Tables (Smithsonian Tables, series D, page 11), for a
range of the barometer from 546 to 578 millimeters, and for a

E. Loomis — Contributions to Meteorology.

range of temperature from —12° to +18° centigrade. The
same table shows the observed reduction as far as the range of
the observations will permit

Reduction of barometer from Grand St. Bernard (elevation 2,462

meters) to Geneva (elevation 407 meters).

Ther.
Cent.

L
0

546.

549.

-12

16944

170*37

167*84
167-02

168-77
16799

16626
165-94

167*18
166-88

164-71
164-66

165-62
165-52

163*20
163-04

164-10
163-88

- 2

161-70

162-59
16200

160*22

161-10
160-40

+ 2

158-78

159*65

157*36

158-23

155-98

156*84

154*62

155-47

153-28

154-11

151*96

152*79

15067

151-50

149-39

150*21

148-12

148-93

552.

171-31
169-83

169-70
168-89

168*10
167-76

166-52
166-37

164-99
164-72

163*48
162-95

161-98
161-46

16053
159-79

15910

157*70

156-32

154-96

153-63

152-33

15103

149*75

555.

558.

561.

564.
175-05

567.

570.

172-24
170-79

173-18

174-11

175-99

176-92

170-62
169-64

171-55
170-43

172-47
171-19

173-40

174*33

175-26

169*02
168-60

169-94
169-42

170-85
170-38

171-77
171*36

172-69

173-61

167*43
16720

168*34
167-90

169*25
168*69

170-16
169*57

171-17
170-51

171-98

165-89
165*55

166*79
16633

167*69
167-08

168*58
167*84

169*48
168-46

170-38

164-37
163*90

165*26
164*71

16615
16549

167-04
166-27

167 93
166*97

168*82
167-63

162-87
162-33

163*75
163*18

164*64
163-99

165-52
164*80

166*41
165*61

167-29
166-65

16141
160-85

162*28
16172

163-16
162-55

16403
163-37

162757"
16212

164*91
164*19

165*78
164-90

159-97
159-43

160-83
16040

161-70
161-37

163*44
162-89

164-30
16367

158*55

159-41
159-77

160-27
160-52

16113
161*06

161-99
161-80

162-84
162-58

157-17

158-02

158-87
159*30

159-72
160-03

160-57
160-75

161-42
161-51

155-80

156-64

157*49
15800

158-33

158-79

159*18
15963

160-02
160-38

154-46

155-30

156-14

156-97
157-77

157-81
158-46

158*64
159-14

15315

153-98

154-81

155-64

156*47
157-08

157-29
157*77

l5iT96
156*29

151-85

152-67

153-49

154*32

155-14
155-31

150-56

151-38

15219

153*01

153-82

154-63
154-83

578.

177-84

176-17

174-52

172-88

171-28

169-71

168*17

166*65
165-57

165*17
164-57

163-70
163-33

162-27
162*17

160*87
161*16

159-48
159-87

15812
158-50

156*78
157*26

155*45
155*70

We see that the observed reduction accords with the compu-
ted reduction much better than in either of the preceding cases.
The change in the value of the reduction due to a change
either of the barometer or thermometer is, however, a little less
than that computed from the formula.

The other elevated station selected is the Colle di Valdobbia,
situated about 10 English miles south of Monte Rosa, at an
elevation of 2,485 meters above the sea, and the station selected
for comparison is Alessandria, distant about 70 English miles,
and elevated 98 meters above the sea. The observations are

E. Loomis — Contributions to Meteorology.

published in Bullcttino Meteorologico dell' Osservatorio in Mon-

calieri, and the years selected for comparison are those of 1877,

8 and 9. The observations were reduced in the manner

already described on page 10, and the results are shown in the

following table which is arranged in the same manner as the

preceding table.

eduction of barometer from t'n/le dl VnldnWa (I'/rva/ion 'J, 485 meters)

to Alestandri'i (elevation 98 meters).

sw.

-.v. m.

198-34

199-44

200-63

901-68

203-73

J0:fS2 ■K.U-'rt

ws-aa

301-12

208-31

909-31

197-00

19644

197-53

200'TS

201-rt7 •1H2-.ii)

1 li.-, ■ 14

206-33

201-31

107-4.'"

191-60

197 49

197*47 1

203-19

Sf>4-?6

194-6 T

Ifif.-t.i5

ll'K-iJ-i

199-95

30103

206-34

194*61

196-48

l!iC-07

198-86

197-13

'im-21

203-33

. L

193-81

19481

195-91

197-(MI

]!>*■■'■"

ifj;i-i i

10O-30

203-40

19215

1 03*83

194-68

195-47

ii»;i"

lflli-41

196-52

i L

1 90-34

192-00

193-06

194-11

liif.Hi

1911-22

f.'-.-lX

198-33

i:i;i-::m

2('">'-ll

Jill -51)

1 0

190-46

191-47
190-39

193-49

191-26

19328

I93-B3

i!M--ii;

\-M-M

i !.:■■ i:i

189-11

: S3 -a i

193-36

194-40

196-45

iiii;--1:i

Hi 7 -54

198-58

199-63

u 0

190-86

191-64

i 92-01

192-53

193-04

183-61

194-01

194-27
195-73

194-63

»l

187-43

189-50

iihi-;,4

191-58

193-66

1 94-69

196-18

1:i7-mii

190-46

iiii'fi;'.

191-46

192-01

192-55

193-06

193-67

194-1 2

i L

]s,v7:i

186-18

isa-si

l-i)-:-4

190-87

199-93

193-95

194-98

19601

* 0

189-20

189-82

190-37

190-98

iiMT.i;

192-06

192-68

193-13

18401

186-OB

186-1 1

1ST -12

189-16

1 90-18

191-20

192-21

193-23

194-95

l-s-.ll

18908

189-68

190-34

i:m is

191-31

191-87

i L

183-43

183-44

184-46

196-46

18846

181-41

188-48

190-49

191-60

199-61

9 0

187-69

188-31

189-01

189-66

I9IC2H

18-n-ro

in L

1 Stl-H 1

182-81

183-81

184-81

185-81

186-81

181-81

198-81

189-81

190-81

ill Q

18G-98

l.-tT-liT

\ii!i-.il

1 88-9 1

1S9-69

119-91

180-20

181-20

18219

183-18

184-11

185-17

lsiiii;

181-15

188-15

189-14

12 0

185-63

18649

1S7-II1

187-10

188-30

., L

111-64

118-62

179-61

180-59

181-53

182-66

183-56

184-53

185-52

186-60

181-49

14 0

186-14

186-78

186-41

1S7TK!

1G L

17611

Ill-OS

178-05

119-03

[60-98

181-96

182-94

183-93

is-vm

185-81

u L

183-87

184-52

185-33

186-89

186-29

17480

176-64

171*50

I1S-47

179-44

18041

1 SI ■:■'.*

182-34

183-31

tBA-SB

ru5

IN-l-Hi'j

184*21

184-42

n:in

174-01

176-03

175-99

116-95

171-91

179-83

1BO-79

181-75

182-71

183-19

183-14

183-15

This table shows results quite different from those of the

pre

cedin

* tabl

e. Vv

bile t

he pp

ssure

at tb

e upp

31' sta

ion r

mains unchanged, the observed change in the reduction to the
lower station resulting from a change in the temperature of the
air-column is 30 per cent less than that computed from the
Laplace formula with the constants of Delcros. While the

14 M Loom is — Contributions to Meteorology.

mean temperature of the air-column remains unchanged, the
observed change in the reduction to the lower station resulting
from a change of pressure at the upper station, is only one-half
of that computed from the formula. Thus we see that the re-
duction of barometric observations to sea-level follows different
laws at different localities. The following table shows a sum-
mary of these results for these five mountain stations :

Change of redaction depending npon
Stations. Thermometer. Barometer.

Mt. Washington, 0*973 +0*142

Pike's Peak, *6T5 + *195

. Summit, Cal., *590 — *866

Grand St. Bernard, *912 + *989

Colle di Valdobbia, *695 + *500

Mean, 769 + *192

Column 1st 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
temperature of the air-column, and compared with the change
computed from the formula; column 3d shows the average
value of the observed change in the reduction resulting from a
change of pressure at the upper station, and compared with the
computed change.

A comparison of these results shows that the temperature
coefficient employed by Delcros and Guyot is too large ; and
the observed values of the reduction to sea-level would in most
cases be somewhat better represented by assuming a larger
value for the coefficient 18336 meters or 60158*6 English feet
adopted by Laplace from the observations of Eamond made
more than 75 years ago. Tt does not seem possible, however,
by any change of these coefficients to modify the Laplace
formula so that it may satisfactorily represent the results at all
of the preceding stations; or even at a single station for all
variations of temperature and pressure.

The Laplace formula assumes that the atmosphere has
attained a condition of equilibrium, and in such a case it gives
the 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 observations
this equilibrium is very much disturbed. The mean between
the temperatures at the upper and lower stations does 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 formulae of reduction now employed may be consider-
ably improved ; but it does not seem possible that any single

R Loomis — Contributions to Meteorology. 15

formula with constant coefficients 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 formulae 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 d B,

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. The
following expression represents very well the observed values
of the reduction for Mt. Washington.

Redaction =

6-499-0-0164 rf T+ 0*0039 tf B+0 07 sin (4°'235 dT— 41°'l75),

where cTF represents the excess of the temperature of the air
column above 28° F., and d B represents the excess of the
barometer on Mt Washington above 23*5 inches. By adding
another term representing the variability of the barometric
correction the formula may be made to represent the observa-
tions still more closely ; but this term is so small in amount
that it cannot be satisfactorily determined without observations
continued for a longer period.

The observed values of the reduction given for Mt. Wash-
ington may be condensed into a small table which shall
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 applying
the proper barometric correction, these averages are all reduced
to toe 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

E. 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 ; column 6th shows the reduction from Summit to
Sacramento when the barometer at Summit stands at 23*3
inches, and column 7th shows the correction for 0*1 inch in the
barometer, which correction is negative when the pressure
increases.

deduction of barotnetric observations.

Therm.
Fahr't.

Mt. Washington

and sea-level.

Barometer 23*5 Inches.

Pike's Peak

and Denver.

Barometer 17*6 inches.

Summit

and Sacramento.

Barometer 23*8 inches.

Redaction.

Correction
0*1 inch bar.

Reduction.

Correction
0*1 inch bar.

Reduction.

Correction
0*1 inch bar.

-10°

7*158

•0021

7-600

•0070

— 5

7-054

•0056

7-541

•0060

6*943

0061

7-448

•0022

+ 5

6831

•0039

7367

•0022

6-732

•0015

7290

•0013

6657

0032

7-227

•0023

6586

•0032

7*179

•0108

6520

0047

7-112

•0077

6*982

-•0180

6-450

•0068

7055

•0086

6-942

— •0138

6-374

•0074

6-993

•0113

6*888

— 0182

6-307

•0035

6-929

0132

6-833

-•0216

6-239

•0024

6858

•0150

6-791

— •0286

6173

•0024

6786

•0157

6-742

— 0343

6-107

•0027

6-725

•0160

6-663

— •0307

6037

•0026

6-716

•0057

6-599

— •0286

5-968

•0022

6-558

— •0267

6520

— •0370

•

6480

— •0400

6-432

The irregularities of these numbers may be diminished by
taking the mean of each three consecutive numbers in each
of the vertical columns ; but I prefer to leave the numbers
precisely as they have been derived from the preceding tables.

If the formulae of reduction to sea-level hitherto employed
are admitted to be unsatisfactory for great elevations, it does not
seem safe to conclude that they are correct for small elevations.
For elevations less than 1000 feet the error of reduction is less
palpable than for an elevation of 6000 feet, but it is probable
that the error is only proportionally diminished.

Height of the Signal Service stations.

In my 12th paper I gave the results of some computations
which indicated considerable errors in the assumed heights of
some of the stations of the Signal Service. The publication

E. 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
sea-level, affords materials for a new determination of these
heights. The following table shows all the stations of the
Signal Service whose elevation above the sea is more than
1000 feet, and for which the mean heights of the barometer are
given for a series of years. Column 1st 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 tnau 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 isobara drawn upou a chart of the United States. This
chart is exhibited upon a greatly reduced scale on Plate I.
From this chart the most probable mean pressure for each sta-
tion was derived, ami 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 Tables which are founded upon Plantamour's formula.
The height of Pike's Peak was obtained by computing first its
■■!■" .i. m above Denver from tie' observed values of the _prep-
iii .ii.nl temperature at those stations, and adding this r^.uBl
1 iii ; !ii >f Denver computed from the data contai' pit and

feral of these stations bnr,v6rkrn,*"-" ^\-i-
|B8urer»ent so far asJi200 -■"■'"/ encie5ei
tax reached" nj ine par*-- ^nclu3iv'ely.
f,m.-- lts 'ater formatK
and disintepi'!*"

18 H. C. Hovey — Danger from Goal-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 Tables, and that they may be depended upon
for heights deduced from the mean of a long series of baro-
metric observations.

Stations of the TT. S. Signal Service whose elevation above the sea

is more than 1,000 feet.

Temperature.

Elevation.

Station.

Lat.

Long.

Elevat'n Mean
Sig. Ser.' Barom.

Barom.
Sea-lev.

38*8

Station.

Sea-lev.

Laplace.

Planfr.

Pike's Peak __

105*0

14150 17-750

19°*2

55*4

30*032

14054

14116

Santa Fe

35*7

106-2

6851 23*265

48-8

58*8

30023

7011

7029

Mt.Washing'n

44*3

71-3

6285

23-626

25*9

45-5

29-973

6286

6319

Cheyenne

41*2

104-7

6057

24-015

44-8

51-4

30*031

6068

6093

Pioche

38*0

114-4

5778

24*039

54*9

55-9

30*037

6143

6166

Virginia City.

45-3

112-0

5480

24-238

41-0

496

30039

5788

5810

Denver

39-7

105-1

5269

24779

49-3

54-2

30032

5260

5278

Salt Lake City

41-2

1120

4362

25-642

524

53-3

30042

4342

4355

Winnemucca-

410

117-7

4335

25-621

50'2

54-1

30050

4366

4379

Boise City

437

116-1

2877

27144

52-4

30*060

2795

2804

North Platte. | 41-1

100-9

2838

27-057

48-7

51-7

30-029

2841

2851

Dodge City _-| 37 6

100*1

2486

27-381

541

56*6

30033

2549

2557

Bismark 46'8

100-6

1704

28-154

410

42*7

30-010

1708

1716

Yankton : 42*7

97-5

1275

28-718

45-8

49-5

30023

1205

1208

Fort Sill '34-7

98-5

1100

28*779

60*6

30032

1188

1192

Omaha

41-3

96-0

1077

28-876

49-8

50*8

30030

1068

1072

In preparing the materials for this article, I have been as-
sisted by Mr. Henry A. Hazen, a graduate of Dartmouth Col-
lege of the class of 1871 ; and Mr. Orray T. Sherman, a
graduate of Yale College of the class of 1877.

Art. II. — Coal Dust as an element of danger in Mining ; by

Kev. H. C. Hovey, A.M.

Chemical action is often induced in heaps of slack, such as
s<yJst in thick coal workings, and the heat evolved may be
For eib to cause ignition. The danger is greatly increased
palpable t broken coal is comminuted and floats in the air in
that the errol is* . which under various conditions may undergo

Height oj nts ^1QW ^*» ^hen the particles are so

In my 12th paper I gave the results orf a safety-lamp, an

which indicated considerable errors in the as&auerman states

some of the stations of the Signal Service. Thtiosions have

& of a blast,

B. 0. Sovey — 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 beiore 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 adjacent 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
from more distant galleries had but conjectures to offer ; and
the only facts definitely ascertained were gathered by an ex-
ploring party led by Mr. Gilpin, who, shortly after the original
; explosion, and at the risk of life, descended into the pit and
i penetrated as far into the workings as the after-damp w^1 "*•
; allow. The locality where the unfortunate workrry^ % ^°E&!T*
' they tried to save were known to be was 1200 ^V ?ncl65ei.v
the shaft; and the point reached by the par^f™^*81™1*. '
600 yards in that iiv^^ They toor*"* later iov™^

of men and horsfgion are the result of decomposition and disintegrrs"
Others by the »nsequently an easy task to discover the source of

was the split*6*06.

20 //. C. Hovey — Danger from Coal-dust in Mining.

and the conclusion was plainly justifiable that the flame of the
explosion had not extended thus far.

The walls of the galleries had 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
force of the blast, and lay in waves and drifts on the floor of
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 whose business it was to clean and distribute
safety lamps to the miners.

Secondary explosions caused by extracted or generated gas
are nearly always in the vicinity of the first one ; but here is
a case where the second was half a mile from the first, with an
intervening space of at least a quarter of a mile known to hare
been free from flame, and presumed to be free from gas, be-
cause men were in it with lamps which showed no indications
of its presence.

Water was continually trickling down the shaft, and the
levels for some distance around were very wet hence the dust,
as soon as it touched the wet walls would be made innocuous;
but the fine, dry particles of carbon that were driven on into
the lamp cabin were ready for ignition. It had been the cus-
tom for years to keep an oil lamp burning openly here, as the
proximity of the shaft and consequent purity of the air made
the practice, under ordinary circumstances, perfectly safe.
But on this occasion it seems to be certain that the ignition of
the coal dust 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
flood the whole mine. It was as if the wadding of a gun were
composed of an inflammable material, which on firing the
charge doubled its effect. It should also be noted that, as a
rule, the Albion mines were very dry, except in portions
nearest the shaft, and the accumulation of dust was very great
I have only aimed to publish the facts, hoping that some one
else may explain on chemical principles the remarkable exhi-
bition of force, as well as of heat, accompanying the ignition
iof an impalpable and homogeneous powder. Professor Abel's
that tut^ents have shown that even finely powdered slate will

nJ5Pe °^ Sas explosions ; and it is alleged, that there

c uent explosions of flour dust in large mills in

In my 12th papei States. In vierlU*' these facts the matter,

which indicated considcraoiL ^i„is in the .worthy of attention

some of the stations of the Signal Service, i..^ for \^x very

V. HZ. Hidden — Mineral Localities in North Carolina. 21

EI. — Notes on Mineral Localities in North Carolina ; by

Wm. Earl Hidden.

azite from Milhollanavs Mill, Alexander Co. — In August
80) I obtained at this locality some very beautiful crys-
geniculated rutile, which had been found there loose in
. Permission having been obtained to work the prop-
succeeded on the first day's working* in finding these
in situ. In connection with the work I " panned down"
f the loose vein material, and in this manner the mona-
stals were first discovered. There is every probability
the work at the locality is continued the monazite will
id in place in the vein. The rock is a garnetiferous
chist The vein (or pocket as it may yet prove
is about a foot wide at its widest and thus far has
ncovered only about eight feet. My operations were
rily limited, and the locality merits further examina-
Phe associated minerals are muscovite (?), emerald green
1 the prism, very abundant and making up 95 per cent

vein, crystals thin hexagonal tables and unusually
; quartz crystals, elongated prisms commonly doubly
Lted and in parallel groupings, often cavernous; rutile,
eniculated and splendent; some decomposed pyrites with

containing native sulphur ; a few pseudomorphs of
'■ after siderite, in rhombohedrons having the basal and
hedral planes.

►ncentrating by " panning," say 15 lbs. of the loose vein
,1, many hundred minute crystals of monazite would be
perhaps only a half a dozen of which
exceed ^th inch in diameter ; rarely,
; were found of Jth inch in length. Under
croscope, the majority of the minute
be crystals are seen to be perfectly trans-
and of a topaz color. The planes are
ghly polished and lustrous. The crystals
formlv long prismatic with modified ter-
>ns, the prism having the shape of an
homboid, thus differing from those pre-
figured. The adjoining figure represents
nmon form with what are supposed to be the prop*
s of the planes. One of the monazites partly enclwet '*
al of mica, which fact would point conclusively »"
nation in the vein and also to its later format^

oils of this region are the result of decomposition and disintegrrC

it is consequently an easy task to discover the source of
the surface.

22 W. & Hidden — Mineral Localities in NorUt Carolina.

The monazite of this locality, as regards occurrence and
form, is essentially the turnerite of Levy, which has been shown
to be identical with monazite, as was long ago suggested 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 physical char-
acters of the mineral will be described by Dr. E. S. Dana.

Other localities for monazite * — In Burke County, monazite
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 chemically pure monazite were obtained
here by sifting old "tailings'' and picking out the largest
crystals ; these were sent to Mr. T. A. Edison, who desired the
mineral for the thorina which it was supposed to contain.

The crystals are usually well formed and vary considerably
in habit. Figs. 446 and 448, Dana, are common ; they are
usually very small, though some were found here of Jth 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. 1 believe that pannings from any of the streams
where the local rocks are mica schists would bring it to light
In the auriferous gravels of McDowel, Rutherford, Burke and
Polk Counties, N. C, it was noticed in every " panning."

In Mitchell County, at the Deake mica mine, I found well
formed crystals of monazite in situ in mica schist. They
were of uncommon size. One measured 1£ inches long by "{
inch in width, and was one of a group. Half a pound of crys-
tals were obtained in all. They were partly coated with
autunite, and were intimately associated with uraninite, gum-
mite, garnet, etc. The characteristic perfect basal cleavage was
commonly observed at this locality. In Yancey County, at the
Eay mica mine on Hurricane Mountain, I found monazite in
white orthoclase. The crystals were very fine, and complex
in form; specific gravity 5*243. Dr. F. A. Genth has been at
work for some years on the monazite of North Carolina and
has separated over a pound of the oxalates of the rare earths
of the cerium group from it. We shall await with interest the
publication of his results.

Uraninite (pitchblende) occurs at the Deake, Lewis and

Flat Bock mica mines in Mitchell County. Pure and unaltered

jiasses of several pounds weight have been found. Cubes and

wjjjc^o-octahedrons imbedded in feldspar were obtained at the

some 0s ^ne w*fck a *kin coating of uranotil or gummite. Some

* Cieol. N. Car., Kerr, 1880, p. 84.

W. E. Hidden — Mineral Localities in Nortfi Carolina. 23

of the uraniuite masses had a submetallic luster, quite like mag-
netite, and much of it was devoid of any pitchy appearance.
Oummite* uranotil and uranochre^ 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
Bock mine, which is partly unaltered uraninite. According
to Dr. Genth,f 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 purchasers. 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
species.

Quartz crystals from Alexander County. $ — Some inter-
esting quartz crystals, found in Alexander County, are repre-
sented in the following figures. Among them, figures A, B,
C and D, are examples of crystals terminated solely by
planes in the 2-2 zone, which feature, as far as the writer can
gather from the literature on the species, is new. Only in the
counties of Iredell, Catawba, Alexander and Burke in North
Carolina, aud at Cumberland, K. L, have I found crystals hav-
ing this interesting form. The series of planes above 2-2 are
mostly rounded, but commonly have a good polish. They are
invariably striated parallel to the edge of 2-2 /%. Right and
left-handed crystals are found. The crystal shown in fig. C
is of interest since the edge between 3 and 8 is replaced by a
plane, and since it has the dihexagonal prism i-2. Special
attention is called to the basal truncation, fig. E, and to the
plane between R and R in the — i zone ; also to certain in-
verted (depressed) triangular markings like those on cryst?'

* Locality discovered by Prof. Kerr in 1877 ; see this Journal, xiv, 496.
fGeol. N. C, Kerr, 1880, page 34; also American Chemical Journp
1879.

% Geol. N. C, Kerr, 1880, page 87.

2-i W. E. Hidden — Mineral Localities in North Carolina.

of diamond. The basal truncation and the (new ?) plane in
the — J zone occur usually rough, though in two instances they
were well polished planes.
Fig. F has the di hexagonal
pyramid in the i-2 zone. Fig.
G represents a crystal almost
wholly terminated by the
rhombohedron 3. This plane
is very common and largely
developed on the Alexander
County crystals. A fine ex-
ample of this rare form is
in the cabinet of Mr. J. A.
Stephenson of Statesville, N.
C. Fig. H shows a crystal
having the planes 2-2, 3.§,*
and 4-£* beveling every pris-
matic face at its intersection
with i£and — 1, It also has
other interesting rare planes.
This crystal was perfectly
pellucid, had a beautiful yel-
low tint and al! 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 areoften found
showing this second formation in parallel position.

All the figures were drawn directly from the crystals and are
of natural size; the determinations of the planes were made
with an improvised goniometer and my lettering therefore may
be only approximately correct.

Beryls from Alexander County.^ — Figs. 1 and 3 represent

the extremes in form of these beryls. The crystal, from which

fig. 3 was drawn, was at first mistaken for quartz. It was quite

small, clear, had both ends terminated and with only a slight

tint of green apparent A crystal of this type but of more

interest was collected by Mr. Stephenson from this same

locality. It was terminated almost wholly by the planes 3-J

and 4-J. Fig. 2 is the most common form at the locality

formerly known as the "Warren farm." They have been

cound there loose in the soil, of a light chrome green color,

-vine prisms of six and twelve sides, and with polished ter-

/itions; the prismatic faces have a characteristic feature of

w '■striated horizontally as if having been scratched with a

ore probably 64 and 8-|. fGeol. N. C, Korr, 1880, page 88.

W. E. Hidden — 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
States. Those occurring in the soil 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.

5-*.

/«

/ 2

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.

Platinum. — 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
oj 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, ] 880.

♦This Journal, vol. xxi, Feb., 1881.

26 C. B. Comstock — Variation of a Zinc Bar.

Art. IV. — Variation in Length of a Zinc Bar at the same Tem-
perature; by Gen. C. B. Comstock.

[Communicated by Authority of the Chief of Engineers, U. S. A.]

The U. S. Lake Survey possesses a steel normal meter des-
ignated as (R. 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 thermometer. Both were made by Repsold.
It has also a base-measuring apparatus by Repsold of which
the essential parts are tubes of 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 zinc 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,
these comparisons may give additional data. Mr. E. S. Wheeler,
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 tha.*
they were made with an apparatus constructed by Repsold, in »
comparing-room lined on all sides with saw-dust ; that this lira -
ing reduces the diurnal temperature fluctuation to 0°'3 F.; tha/fc
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 F., one lying on each meter.

In the experiments with the zinc bar of (M. T. 1876), this
meter was alternately heated and cooled, and after each heating
or cooling was compared with (R. 1876), which remained iti [
the comparing-box during the twenty days covered by the ex-
periments, its temperature varying in that time only about 3° '
F. In heating (M. T. 1876) it was taken from the comparing-
room at a temperature of about 36° F. to another room, and
kept at a temperature between 70° F. and 80° F. for twenty
hours or more, then it was replaced in the comparing-boX*
where it cooled slowly to the temperature of the comparing*

at the 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 temperature 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 comparing-room, and compari-
sons were made as before with (R. 1876). Temperatures of
greatest cooling and heating were taken with maximum and
minimum thermometers.

From 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 1876) = steel bar of (M. T. 1876) +46^7 -0^-39 (<-32°) ;
zinc bar of (M. T. 1876)= steel bar of

(M. T. 1876)+267/'-5+10/'l5 (*-32),

in which expressions I is the temperature in Fahrenheit degrees.
The residual errors have been computed with these values.
A.8 the temperature-range was small during the comparisons
riven 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 IS""11 by 27mm. In computing residuals the tem-
perature of (M. T. 1876) is 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
1[ to a temperature of —3° F., and afterwards is allowed to return
gradually to its original temperature of 36° F., it will have a
certain other lengtn ; and that these lengths at the same
temperature may differ by fifteen microns. Both (R 1876)
and the bars of (M. T. 1876) were freely exposed to the air
inside the comparing-box. If any large portion of the appa-
rent change in length of the zinc bar ot (M. T. 1876) was due
to temperature errors, the residuals of the steel bars should
show it at least in part.

IT.

C\ B. Comstock — Variation of a Zinc Bar

Tables giving dates, temperatures and residuals of comparisons of
(R. 1876) and (M. T. 1876) made after periods of heating and
cooling of (M. T. 1876.) Preliminary reduction.

1. (M. T. 1876) heated, Feb. 7 to Feb. 14. 10.50 a. m. and kept at temperatures
between 70° and 80° F.

Date of
Comparison.

Tempera-
ture of
(R. 1876.)

Tempera-
ture of
(M. T. '76.)

(R. 1876)— <M. T.

1876)*, computed,

minus (R. 1876)—

(M. T. 1876).,

observed.

(M. T. 1876),— (M.

T. 1876),, computed,

minus (M. T. 1876),

— <M. T. 1876),,

observed.

1881.
Feb. 16, 9.14 a. m.

37°02 F.

36?91 F.

-0-4

— 18-6

" 16, 8.19 p.m.

36-92

36-81

-1-7

-17»8

" 17, 9.12 A. M.

36-52

36-41

-0-4

-17*6

u 17, 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.m.

36-32

36-21

+ 1-2

-17-5

" 19, 9.25 A. M.

36-37

36-31

+ 30

-16*4

" 19, 8.05 P. M.

36-42

36-41

+ 0-5

— 14-4

" 20,10.38 a.m.

36-32

36-21

+ 1-7

— 15-6

" 20, 8.37 P. M.

36-42

36-41

+ 1-3

-12-7

" 21, 9.56 a.m.

36-52

36-41

+ 3-2

-14*2

11 21, 8.09 P.M.

36-62

3661

+ 1-0

-13*9

" 22,10.12 a.m.

36-72

36-71

-1-2

— 13-7

" 22, 8.44 P. M.

37-12

37-21

+ 0-9

— 12-3

" 23, 9.22 A. M.

37-32

37-26

— 0-9

— 15-3

" 23, 7.35 p. M.

3707

3701

+ 1-1

-148

" 24, 9.17 A. M.

36-52

36-51

+ 1-4

-13*8

2. (M. T. 1876) cooled for 23 hours: Feb. 24, 10.00 A. M. to Feb. 25, 9.30 a. m.
and kept at temperatures between —1° and —6° F.

Feb. 25, 7.22 P. M.

35-52

35-42

" 26, 9.03 A. M.

34-91

3482

" 26, 9.38 P. M.

34-91

34-82

" 27,10.22 a.m.

35-31

35-22

" 27, 7.43 P. M.

35-91

35-81

+ 2-1

+ 2-4

— 0-5

+ 4-0

+ 1'6

+ 0-4

+ 03

— 0-6

+ 1-7

3. (M. T. 1876) heated for 22 hours: Feb. 28, 11.30 A. M. to Mar. 1, 9.10 A. m.,
being kept at temperatures between 70° and 80° F.

Mar. 2, 9.11 A. M.

37-02

36-96

-15-8

u 2, 9.04 p. M.

36-72

36-61

+ 03

-15-3

" 3, 9.07 A. M.

36*32

36-21

-0-2

-160

" 3, 8.51 p. M.

36-32

36-21

o-o

-157

" 4, 9.09 A. M.

36-32

36-21

-2-4

-14-3

4. (M. T. 1876) cooled for 24 hours: Mar. 3, 9.30 a. m. to Mar. 4, 9.30 A. M.,
being kept at temperatures between —2° and — 5° F.

Mar. 5, 8.58 P. M.

36-72

36-61

+ 2-6

+ 6*6

" 6, 9.50 A. M.

3682

36-71

+ 2-2

+ 6*4

" 6, 8.04 P. M.

37-22

37-16

+ 1*1

+ 6-0

" 7, 8.52 A. M.

37-32 •

37-21

+ 1-4

+ 5-1

" 7, 7.56 P. M.

37-58

37-51

+ 2-8

+ 5-3

u 8, 9.03 A. M.

37-88

37*81

+ 3-0

+ 5-3

at the same Temperature. 29

(M. T. 1876)8 denotes the steel bar of (M. T. 1876) and
(M. T. 1876)z, the zinc bar // is the symbol for micron or
thousandth of a millimeter.

The tubes of the Eepsold base-apparatus have already been
spoken of. A similar experiment was tried with these tubes.

The zinc bars of tube No. 1 and of tube No. 2, as well as
their steel bars, were first compared with each other at about
41° F.; then tube 1 was heated for twenty-four hours to a
temperature between 70° and 80°, and after the heating the
.two zinc 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

^=8',,+ 1518^8 - O^-oe*,
Z'1=Z'1+ 210^6 -0^44*,

where t is the temperature of the comparison in Fahrenheit
degrees. The lengths designated by S\, S'a, Z\, Z'a, are each
very nearly four meters; but are not the lengths used in base
measurement The former are in the neutral axes of the
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. Subtracting it from the differ-
ence of lengths of the two bars at that temperature as com-
puted from the equations given above, the residuals result.
When positive, they indicate that the observed difference
of length of the two bars was algebraically too small.

The first column gives the date of the comparison; the
second and third, the mercurial temperatures of tube 1 and
tube 2; the fourth, the residuals of the steel bars or S'j — S'a
computed, minus S',— S'a observed ; the fifth, the residuals for
the zinc bars or Z',— Z'a computed, minus Z',— Z'a observed.

C. B. Comstock — Zinc Bar Variation.

Preliminary Reduction.

Date.

1881.

Mar. 14,
15,
16,
17,

((

9.40 A. M.
9.39 P. M.
3*36 P. M.
9.21 A. M.

3974 P.
40*58
41-19
41*90

39-82 F.
40-67
41-80
4190

Z'i — Z'»

residuals.

—2*3
—5-2
— 2-5
—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. 18, 8.15 p. M.

46-51

45-12

-101

-58-9

" 19, 9.44 a.m.

44-25

43-69

- 8-4

-46*8

*' 19, 2.32 P. M.

44-02

4352

+ 0-9

-38-8

" 19, 8.08 P. M.

43-88

43*50

+ 2-7

—42-1

" 20, 9.39 A. M.

43-66

43-37

+ 4-6

—33-5

" 20, 8.35 P. M.

43-70

43-45

— 6-4

— 38-8

" 21, 10.23 A. M.

43-47

*" 43-33

+ 3*5

-35-3

" 21, 8.17 P. M.

43-51

43-32

+ 1-1

-33-4

" 22, 9.12 A.M.

43 33

43-12

+ 2*6

-28-8

" 22, 8.43 P. M.

4303

42-90

- 4-9

-26-4

u 23, 9.18 A. M.

42-76

42-59

— 0-6

-29-7

An examination of the residuals shows that the mean

residual of S',— S'a before heating was — 5^*8, and allowing
forty-eight hours to cool, that the mean residual from 9h 89m

A. M., March 20, to 9h 18m 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'j— S's. But the mean residual of Z'j—Z', before heating

was — 8^*1, and after heating, between March 20, A. M. and

March 23, was - 32^2, a change of 29M.

It seems, then, that the heating from 41° F. to 75° P.,
and subsequent cooling 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 change found for the zinc bar of the meter (M. T. 1876) for
a temperature change from —3° to +75°.

Sufficient data have not yet been obtained to determine the
time required for a zinc bar to lose this probably temporary
change of length. In the case of glass thermometers it is
known that sub-permanent changes of form lasting for many
weeks occur on heating them.

The question at once occurs, whether bars of other metals
may have sensibly differing lengths at the same temperature.

U. S. Lake Survey Office, Detroit, Mich., April 30, 1881.

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 Eocene 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

fenera : Dinoceras Marsh, the type genus, Tinoceras Marsh, and
Jintatfierium Leidy. These will be fully described by the writer
in an illustrated monograph now nearly ready for publication.
This 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.

The 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 tnis affords ample material for a restoration which
will represent very nearly the osseous framework of the animal
when aliva Such a restoration has been attempted for the
memoir in preparation, and in the present article a much
reduced figure of this is given (Plate II), which shows the
general proportions of the type species.

Among the points of special interest suggested by the
restoration of Dinoceras here presented are the following :

(1.) The absence of a proboscis. There is no evidence in the
skull of the existence of such an organ, and the proportions of the
neck and fore limbs certainly rendered its presence unnecessary.

(2.) The "horn-cores" of the skull. An examination of a large
number of these, from individuals of various ages, indicates
that the posterior pair, on the parietals, were sheathed with
thickened integument, which may have developed into true
horn, as in the Pronghorn (Antilocapra Americana). The sur-
face of the osseous protuberances is very similar in both cases.
The pair of elevations on the maxillaries are equally rugose,
and bear evidence of a similar covering. The small tubercles
on the nasals are usually smoother, and were probably without
horn-like sheathing. The three pairs of elevations are present
in both sexes, but are proportionally smaller in the females.

(3.) The canine tusks, also, are common to both sexes, but
those of the males only are large and powerful.

(4.) The dependant processes of the lower jaio correspond in size
with the canine tusks, and are evidently adapted for their pro-
tection. In the females, these processes are but slightly developed.

(5.) The sternum is composed of flat horizontal segments,
not compressed and vertical, as in Perissodactyls.

32 A. Liver sidge — Torbanite of New South Wales.

The material now available for a restoration of Tinoceras
grande Marsh, is sufficient to show that this animal was similar
in general proportions to Dinoceras mirabik, but of much
larger size. The 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; and the
evidence now at hand seems to indicate that Uintatherium is
the oldest and most generalized form of the Dinocerata. One
specimen in the Yale Museum from near the original locality,
and agreeing, so far as the comparison can be made, with the
type, has four lower premolars. This character will serve to
distinguish Uintatherium from Dinoceras, to which it has various
points of resemblance. Tinoceras is from a horizon higher than
Dinocei*as, and is much the most specialized genus of the group.

Yale College, New Haven, June 14th, 1881.

Art. VI. — On the Torbanite or " Kerosene Shale" of New South

Wales; by A. Liversidge.*

The so-called " kerosene shale" does not differ very widely from
cannel coal and torbanite. Like cannel coal, it usually appears to
occur with ordinary coal in the form of lenticular deposits. Like
cannel coal also, when of good quality it burns readily, without
melting, and emits a luminous smofcy flame. When heated in a
tube it neither decrepitates nor fuses, but a mixture of gaseous
and liquid hydro-carbons distils over.

In color it varies from a brown-black, at times with a greenish
shade, to full black. The luster varies from resinous to dull.
When struck it emits a dull wooden sound. The powder is light
brown to gray ; the streak shining.

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 specimen sent to him was not from
Wollongong, but from Hartley.

Analyses afforded: — -1, 2, 3, From Joadja Creek, color black,
brownish, sp. gr. 1*103, 1*054 and 1*229; 4, From Murrusundi,
dark-gray, but with white clayey specks.

Loss at 100° C. 1-160 "440 *040 1*165 !

Volatile hydro-carbons 73S64 83*861 82-123 71*882 |

Fixed carbon 15-765 8035 7-160 6-467

Ash 9-175 7075 10340 19936

Sulphur -536 -589 -337 '549

A specimen from the Hartley seam, where most free from min-
eral matter, having sp. gr. 1*052, afforded: Moisture and volatile
hydro-carbons 82*24, fixed carbon 4*97, ash 12*79=: 100. An ulti-
mate analysis of the same, dried at 100° C., gave: Carbon 69*484,
hvdrogen 11*370, oxygen, nitrogen, and sulphur 6*356, ash 12*790
= 100.

* Abstract from paper in Proc. Roy. Soc. N. S. Wales, Dec, 1880.

AM. JOUR. SCI- Vol. XXII, 1B8..

W. Ferret — Cyclones, Tornadoes and Waterspouts. 33

Art. VII. — Meteorological Researches, Part II Cyclones, Torna-
does and Waterspouts ; by Wm. Ferrel.*

[Abstract, published by permission of Carlile P. Patterson, Superintendent
of the Unite'd States Coast and Geodetic Survey.]

If all parts of the atmosphere had the same temperature and
the same hygrometric state it would remain in a state of static
equilibrium. The principal circumstance which disturbs this
equilibrium is the difference of temperature between the equa-
torial and polar 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 contrary 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 regions give rise to what are called the
general motions of the atmosphere, depending upon the differ-
I ence of temperature between these regions and independent of
I 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-

f face is equal to the force causing this component of motion,

i and the same with regard to the westward motions. According

to well established principles of mechanics, there cannot arise

any force from the effect of the earth's rotation, which by means

of friction would tend to either increase or decrease the earth's

rotation, and hence the eastward and westward components of

motion must be so adjusted that the sum of all the moments of

I force acting upon the earth through friction and tending to

. affect its rotation, must be equal 0, and hence, as there are

eastward components of motion in the higher latitude, there

must necessarily be westward ones nearer the equator. The

♦ Coast and Geodetic Survey Report for 1878. Appendix 10.
Am. Jour. Sol— Third Series, Vol. XXII, No. 127.— July, 1881.

34 W. Ferrd — 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.

The deflecting force depending upon the earth's rotation is
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 hemi-
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-
ward motion, therefore, in the middle and higher latitudes gives
rise to a gradient of pressure increasing toward the equator, and
the westward motion between the tropics and the equator to a
gradient of pressure increasing in a direction from the equator,
and hence there must be a belt of higher pressure all around
the globe, having its maximum at the latitude of 30° or 35°i
where the dividing line is between the eastward and westward
motions. The pressure diminishes from this maximum toward
the poles, so that the pressure at the poles, especially the south
pole, is less than at the equator. As the southern hemisphere
is mostly covered by the ocean, on which the friction is much
less than on land, the eastward velocities in the middle and
lower latitudes of this hemisphere in their normal state, amount
to almost a gale entirely around the globe, and these give rise
to a very steep gradient there, and a great barometric depres-
sion at the south pole.

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
the earth's surface, comprising both sea and land with its moun-
tain ranges. This part of the subject was treated in Part I, of
these researches, but some knowledge of the principles contained
in this part of the subject and of the results is necessary to
understand the theory of cyclones, tornadoes, etc.

Cyclones. — Cyclones arise from more local disturbances of
temperature. On account of the want of homogeneity of the
earth's surface and of the hygrometric state of the atmosphere,
the amount of heat received and radiated by the earth's surface
and the atmosphere, is very different in different localities.
Where more heat is received than radiated, the temperature
must continue to rise until the loss of heat by radiation and
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 general
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 tn 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 a cyclone. There would
be a motion of the air from all sides toward the central part of
the warmer and more rare air in the interior, a very slow rising
up of the air in this part and a flowing out of the air above ;
that is, there would be an interchanging motion between the
colder and warmer parts of the air, just as in the case of the
general motions of the atmosphere there is between the
equatorial and polar regions, except that in the one case the
flow is toward the central part below and from it above, while
in the other it is the reverse. Any limited portion of the earth's
surface of not very great extent, may be regarded as a plane,
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 geperal 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
the external 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 by
numerous 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 verv near the surface counter-

36 W. Ferrel — Oyclones, 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, and the gentle southwest winds of the middle lati-
tudes are produced.

The preceding condition, found in the unequal distribution
of temperature, 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
hygrometric state of the atmosphere, and 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 violence. With a dry
atmosphere the air in the ascending current of the interior
would cool about one degree 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
equal to or greater than that of the air generally, unless the
rate of decrease of temperature with increase of altitude in
the latter were greater than 1° C. for 100 meters, which it
never is except in some rare cases and very near the earths
surface only. When this would take place the initial cyclonic
disturbances arising from this primary cause of disturbance
would cease.

If the air is nearly saturated with aqueous vapor, after
ascending to only a moderate elevation its tension and tempe-
rature are so much diminished that the vapor is condensed
into cloud and rain and the heat given out in the condensation
of the vapor as the air ascends prevents the rapid cooling
which takes place in dry air and the rate of cooling with increase
of altitude is reduced, in ordinary temperatures and eleva-
tions, to less than half of what it is in dry air. If in this case
the rate of decrease of temperature with increase of altitude
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

W. Ferrel — Ch/clones, Tornadoes and Waterspouts. 87

it cools at the rate of 1° C. for each 100 meters before it
reaches that elevation, it may be cooled down lower than the
surrounding air before reaching the elevation where condensa-
tion commences, so that if, in this case, we should have the
conditions of a continuing cyclone at all, the power of the
cyclone would at least be very weak.

Where 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 said to be in a state of unstable equilibrium, since
if from any slight predisposing cause such ascending current
is once set in motion it must continue until this state is
changed, either by the action of what we have called the pri-
mary causes of disturbance of temperature or from the invert-
ing action of the currents set in motion. But an atmosphere
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
large cyclone it would be necessary to have a central region of
warmer and more rarefied air to set in motion ascending cur-
rents over a considerable area, and with this there might be
considerable cyclonic disturbance if the atmosphere were not
quite in the state of unstable equilibrium, but without this
latter condition also we could not have a long continued cy-
clone. It is seen then that the moisture of the air is a very
important element, since without this we cannot have the state
of unstable equilibrium 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, a rate of decrease which is often found in
the atmosphere. The more nearly the air is saturated with
vapor, and the greater the decrease of temperature of the air
• generally with the increase of elevation, the greater is the
power of the cyclone. But without these there may be con-
siderable cyclonic disturbance kept up for some time, arising
from the primary causes of disturbance, even where the air is
so dry that there is very little condensation of vapor into
cloud and rain. Professor Loomis has shown that there is
sometimes a considerable barometric depression for several
days with little or no rain, but in such cases there are only
small gradients with no violent winds, and the depression only
becomes considerable from the gradients extending over a large
area. At the equator where there is no gyration of the area of
rarefaction 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
circular gyrations without any radial motions, except in the
initial state before the radial motions are brought to rest by
means of the friction between the different strata. In this
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
tangent toward the center. This is shown by the mathematical
expression of this inclination deduced from the solution of the
equations expressing the conditions of a cyclone, and this same
expression shows that near the center of a cyclone the gyra-
tions at the surface are more nearly circular than at greater
distances from it, and that, all other circumstances remaining
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 toward
the center, but outward from the center above, where this
motion is from the center.

If any central area for some reason could be kept colder
than the surrounding parts, with a gradient of temperature
increasing somewhat regularly from the center outward, we
should have the condition of a cyclone with a cold center.
This condition is furnished in some measure by an island in a
northern sea in winter, on which the temperature is less than
on the surrounding ocean. In such a case the. interchanging
motions below and above would be reversed, but the gyrations
would be in the same direction around the center in the
interior part as in the case of an ordinary cyclone, and the
contrary in the exterior part. The general motions of the
atmosphere on each hemisphere of the globe, with the cold
poles 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
cyclone, 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
1° 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, wouid give rise to consid-
erable cyclonic disturbance, and, if the island were of consider-
able extent, to an observable barometric depression. A very
remarkable example of such a cyclone exists in the northern
part of the Atlantic ocean. Here, on account of the Gulf
Stream and the^ general interchange of waters between the
equatorial and polar regions, which tend to equalize the tem-
peratures, there is a considerable area of warmer temperature,
especially in the winter season, than that of the sorrounding
parts, with its center near Iceland. This gives rise to a fixed
cyclone with its interior gyrations around this center and fixed
area of low barometer extending over the greater part of the
northern part of the Atlantic ocean. These gyrations on the
southern side of this cyclone, combining with those of the
general motions of the atmosphere, cause the strong west winds
and steep gradients in the middle latitudes of this ocean in the
winter. The belt of high pressure of this cyclone is thrown
somewhat, on the south side, upon that due to the general
motions of the atmosphere at the parallel of about 30° or 35°,
and causes the area of high pressure- in this ocean at these lati-
tudes.

In the summer season the temperature gradients nearly
disappear, and there is very little cyclonic disturbance over
thitf region or barometric depression in the vicinity of Iceland.
Very similar conditions exist in the northern part of the
Pacific ocean, but the cyclonic disturbances and the decrease of
barometric pressure are not so great

40 W. Ferrd — Cyclones, Tornadoes and Waterspouts.

Progressive motions of Cyclones. — Ordinary cyclones, at least
soon after their first formation, become independent of local
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 trie 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
in from all sides toward the center. The direction of progres-
sive motion, therefore, is somewhat in the direction of the
general motions of the atmosphere in all parts of the earth.
Hence cyclones originating near the equator, where there is a
westward component of motion, are carried westward, but those
originating in the middle latitudes, where the general motion
of the atmosphere is" eastward, are carried toward the east
There is also a tendency of cyclones to move toward the poles
where there are no general currents to carry them forward
Cyclones, therefore, which originate in the Atlantic .near the
equator are first carried westward and northward toward the
West India islands, and Florida, until they arrive at the par-
allel of about 30°, where there is no east or west component
of motion, and where, consequently, they move in the direc-
tion of the meridian until they arrive at the middle and
higher latitudes, where the general eastward current carries
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 general
motions of the air are deflected around somewhat toward the
pole, and aid the cyclones in their progress and carry along a
supply of moist air from the equatorial regions for their sup-
port As the power of the cyclone is mostly in the upper
cloud region of the atmosphere where the vapor is condensed
mostly, the progressive motions of the cyclones depend rather
upon the general motions of the atmosphere at considerable
altitudes than upon those near the earth's surfaca Hence
within the tropics, where .the westward motion is small above,
the progressive velocity of the cyclone is small, and it is so at
the vertex of the parabolic path where the motion is toward
the pole, but after arriving at the higher latitudes where the
upper general motion of the atmosphere has considerable velo-
city, the progressive motion of the cyclone is much accelerated,
especially its eastward component

It must not be supposed, however, that the progressive mo-
tion of cyclones depends entirely upon that of the airfin which

W. Ferrel — Cyclones, Tornadoes and WaterspotUs. 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 cvclones a little in advance of the
old ones, the latter gradually subsiding, and this new formation
is mostly likely to occur in the direction of greatest moistura

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 anotner,
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
not very great inclination to these isobars, the motion of the
air is somewhat around these areas in a direction contrary to
that of the interior part of an ordinary cyclone. These areas,
however, do not form systems of winds complete in themselves,
but simply arise from the interference of cyclones, and are
therefore not properly called anti-cyclones.

Tornadoes. — These are simply very small cyclones, extend-
ing over so small an area that the effect of the earth's rotation
has no sensible influence, and the gyrations arise, not from the
gyration of this small area around its center in consequence of
the earth's rotation, but from a disturbed state of the atmo-
sphere in which the tornado occurs which renders it impossible
for the air to flow from all sides toward a center without run-
ning into gyrations around that center. This may be illus-
trated by means of a basin of water with a hole through the
bottom in the center through which the water is allowed
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 Waterspouts.

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 witn 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-
sequently must become very great near the center.

In cyclones the barometric gradient and depression of the
barometer in the central part are due both to the deflecting
force arising from the earth's rotation and the centrifugal force
of the gyrations, to the former mostly at a considerable dis-
tance from the center, but to the latter mostly near the center.
In a tornado the diminution of pressure and tension in the
center arises almost entirely from the centrifugal force, that de-
pending upon the earth's rotation being nearly insensible.
On account of the rapidity of the gyrations near the center
this diminution of pressure may be very great there, while at
a very short distance from the center it is imperceptible.

Tornadoes occur when, from any cause, the air* is in the
state of unstable equilibrium already referred to. This may
be 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 half as great as in the case of dry
air. When 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
case 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 be 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

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
as 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
as those above, it would be similar to such a flue with all the
draught cut off*. But very near the earth's surface these gyra-
tions, and consequently the centrifugal force, are very much
diminished on account of the friction at the surface, and this
allows the air to rush in quite near the surface to supply the
draught of the interior ascending current While, therefore,
the gyrations above, on account of the little friction are almost
exactly circular, allowing little air to reach the central part, the
motion of the air, near the surface, is more nearly radial, or at
least very much inclined inward from the direction of the tan-
gent. It is the same somewhat in the case of large cyclones.
Very near the earth's surface the radial component#of motion
is much greater than it is at a moderate elevation above, and
the inclination from the tangent toward the center may be
very great, while a little above the surface the gyrations are
nearly circular. It is readily seen that this must be the case since
the force which overcomes the friction of the gyratory motion
depends, in both cyclones and tornadoes, upon the radial com-
ponent of motion, and hence the greater the friction to be
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
earth at a considerable distance from the center. In such a
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
throw 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 velocity of the current which has carried it up, is dimin-
ished.

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 earth1 s surface by the rapid gyratory motions near the center
of a tornado. This may be explained by means of a deep vessel,
instead of a shallow 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 in a 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 10° C. below the temperature of the air,
then air at the outer limit has to ascend about 1,00Q 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 gyratory velocity may
be assumed to be very nearly inversely as the distance from the
center, except very near the center, where the gyratory velocity
becomes almost infinitely great Without any friction the
waterspout 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 gyrations,
this is not the case. The diameter of the base of the water-
spout depends upon the gyratory velocity, and where this on
account of friction near the center, is not sufficient to bring the
spout down to the surface of the earth, it is seen merely as a
funnel-shaped cloud.

Small waterspouts which 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 surface of the water. The principle of their formation is
the same, but a greater rate of decrease of temperature with
increase of altitude is required, than when their first formation
commences up in the region of the clouds.

Cloud-bursts. — We have seen how a heavy body may be sus-
tained and kept up in the air near the center of a tornado for a
long time. In the same manner a large accumulation of rain
is sustained, and prevented from being dispersed by the inflow-
ing currents so long as the rain is not carried up where the air
flows 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
it is poured down through 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
mountain side, great ravines may be produced. That these
holes in the earth and ravines are caused by a stream of water,
and not by a very heavy rain, is evident from the fact that the
sides of these holes are often cut down almost perpendicularly,
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 tnat no water falls except in the down -pouring streams.

Cloud-bursts are most apt to occur on mountain sides. The
tornado, heavily loaded with accumulated rain-water, on ap-
proaching a mountain side is very much interfered with by it

46 W. Ferret — Cyclones, Tornadoes and Waterspouts.

The draught of the ascending current, as we have seen, is
mostly near the earth's surface. When 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.

Hailstorms. — As in* tornadoes, there is a stratum of air
brought down to the earth by the centrifugal force of the gyra-
tions, where the condensation of vapor into cloud and rain first
takes place, and which assumes the figure of the water-spout, so
very much higher up there is one brought down, it may be
entirely to the earth, where the tension is so small and the
temperature so low as to freeze the vapor into snow and the
rain-drops into hail, even in the summer season. The altitude
of this stratum, where it is not brought down to a lower level
by the gyrations, depends upon the excess of the temperature
of the air at the earth's surface above the freezing point
Drops of rain carried by the ascending current above this
stratum, or where it is brought down to or near the earth,
within it, are frozen into hail. These may be carried outward
above where the ascending currents are so weak that they
can fall to the earth, and as they may fall very slowly and
may have been cooled down considerably below the freezing
point, they may continue to increase in size all the way down
by freezing the water which adheres to their sides in falling,
for the ascending current would bring a great deal of rain in
small drops and mist in contact with them.

Sometimes much of the hail in thus falling is drawn in
toward the center by the inflowing currents from all sides
below, until there is a great accumulation of hail in the center
of the tornado, just as of rain in the case of a cloud-burst. If
from any cause, then, the strength of these currents should
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

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
another coat of soft snow, less compact than the coat of ice,
after which they are thrown out again above where they fall
gently down and receive another coat of solid ice. This may
be repeated a number of times, the hail-stone moving in a sort
of oval orbit, upward in the central part, outward above, and
down at a distance from the center where the strength of the
ascending current is such as to allow it to fall, and then toward
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 thing to find large hail-stones
composed of a number of coatings like an onion, these coat-
ings consisting 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 almost entirely dry air is in the state of unsta-
ble equilibrium. The sand-spout originates just as any small
tornado, or as small waterspouts upon lakes in fair weather, but
the air is so dry that there is no condensation of vapor, unless
it is at a very great altitude, but the indrawing and ascending
currents carry with them a great quantity of dust and other
light substances, which assume the form of a pillar extending
high up into the air. As occurs in all tornadoes and water-
spouts, the air flows in from all sides below to supply the
draught of the ascending current, mostly near the earth's sur-
face, but also in some degree up to a considerable altitude, and
these inflowing currents drive the dust which is raised on all
sid6s, in toward the central part, and thus the dusty 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 drive the particles from
the center, but this is counteracted by the resistance of the
indrawing currents, which is a function of the size of the 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 as the square of the
diameter. If, however, the particle were very large, it might

* See American Journal of Science, II, vol. 1, p. 403.

48 W. Ferrel — Cyclones, Tornadoes and Waterspouts.

be kept at so great a distance from the center, that the ascend-
ing current there would not be able to keep it up, so that if
there were no limit to the sizes of the particles, yet there would
still be a limit to the dimensions of the pillar of sand, which
would be determined by the ascending velocity of the air at
different distances from the center.

Waterspouts and Sand-spouts are hollow. — Near the center of
the gyrations the centrifugal force is so great that the small par-
ticles of condensed vapor in waterspouts, and of fine sand parti-
cles in sandspouts, cannot exist there, or at least they are com-
Earatively rare, so that these spouts have the appearance of
eing hollow. M. Boue, in the year 1850, observed three
water-spouts at the same time on Lake Janina, from the top of
a high mountain. The weather was entirely clear, without
clouds or wind, but very oppressive and hot. The spouts
seemed to rise up from* the lake, and he could look down into
the top of them and see that they were hollow in the middle.
(Bulletin Soc. Geologique de France, v. viii, p. 274.)

Of a whirlwind observed at Schell City, Mo., in the summer
of 1879, Professor Nipher says : u There were no surface winds
strong enough to bear dust along the surface of the ground, but
the dust carried up in the vortex was collected only at the
vortex of the whirl. The dust column was about two hundred
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 Strait. 49

Art. VIII. — Magnetic Observations made in Davis Strait, in
August and September, 1880, on board the Steamship Gulnare;
by O. T. Sherman.

The Steamship Gulnare was provided with a Laraont 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. 0. A.
Schott, in Washington, and the observer^ 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 Eeport, 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,
N. F., part at the private observatory of Mr. John Delaney, part
on the hill forming the harbor. A local publication contain-
ing information " derived from the most authentic sources/'
gives the variation for 1880, as 32° 30' West. The authority
is not known. Commander Eobinson, E. N., observed in 1878
a value 31° 30'. The variation chart, for 1880, published by
the British Admiralty, shows the line of 31° running 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/#l 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
attraction. The horizontal force observed was 3*3373, the dip
74° 45,-4.

Lively, Disco Island, Greenland, formed our second station.
This place had formerly been visited by Sontag in Sept., 1861,
who found 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'-8-68d 45', dip 81° 56,-81° 43'*7 and horizontal force
1-770-1-805. 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
11th, the declination observed by the magnetometer varied
from K 46° 9#-7 W., at llh 13m a. m., to K 49° 15'*3 W., at 4h
32m P. M. On August 18th, at the same spot, but with an
azimuth compass, the declination varied from N. 67° 54/#l W.,
at 7 A. M., to N. 68° 52H W. at 3 p. 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. Sol— Third Series, Vol. XXII, No. 127.— July, 1881.

50 0. T. Stuerman — Magrittic Observations in DavisjSbraiL

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. A3 vet 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 determina On August
12th. the magnetometer gave a horizontal force of 1*9042. On
August 14th, in the same position as the declination of the 11th
and 18th. 17559. On September 1st, at a station almost mid-
way. 1*8842. 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-
cover some place which might be free from local influence.
Taking the dipping needle, we made observations from the top
of the hills to the sea coast Placing these on the chart they
are found to increase iu value on either side of a knoll of trap
rich in magnetite, on which the dip was 80° 48'. Half way up
the hill it became Slc 6'. on the top of the hill, 81° 23.
Speaking generally, the line 81° 50' runs from a point half
way between Wildfire and Englishman's Bays, along the inner
shore of the island forming the harbor. The line of 82°
runs through the middle of the western part of the island and on
the sea shore on the eastern. The line of 82° 6' on the western
sea shore. AH 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° 53'9, the total force
12 6213? and the variation N. 70° 2''9 W., at llh 30* local time.
The Alert gives for this station a declination of 69° 8'*5 at
6*40 P. M. The station is granitic and there may be local
attraction.

At Sakkak, lat. 70° 1' X., long. 51° 55' W., we found on
August 24th, the dip to be 81° 59'6, variation N. 70° 47'-3, at
12h 15m local time : and on August 31st, the horizontal force
1*7904. This station is also probably affected by local attrac-
tion.

0. T. Sherman — Observations made in Davis Strait. 51

At Kidluset, lat 70° 10', long. 53° 0', August 25th, 1880,
we observed a dip 82° ll'*8, and total force 12*5435. These
are probably not affected by local influence.

The 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 Koads, on June
23d, 1880. The observations discussed by the method of least
squares give the value of the ship's force to head, —1*8403, to
starboard, —0*7845. Three days after, the salt which 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 hammering. The ship
was again swung at St. Johns. The value of the ship s ,
force reduced, after Evans, by the least squares are force to
head, -1*916, to starboard, -0*2599, to nadir, -0*4081. On
August 30th, the values were, force to head, —1*46299, to star-
board, —0*83918. On October 5th, the values became to head,
-0*9971, to starboard, -1*4525, to nadir, -03907. 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

. . ACzfcB,v/--Ca+A9-fBa
«** = -gr^

which is readily deduced from Evans* well known formula.
A, B and C are here easily calculated functions of the semi-
circular and quadrantal coefficients, and the ship's apparent
azimuth. The sign 4- being taken, when the compass reading
is from N. 0° E., to N. 180° K, the sign — for the remaining
readings. The values obtained in this way are as follows :

Date.

Lat. N.

Long. W,

Hour, p. m.

Declination.

August 5, 1880,

62° 30'

51° 45'

8 23

N. 57° 42' W.

September 10,

67° 6'

58° 30'

6 43

N. 70° 59' W.

September 14,

59° 30'

56° 26'

6 27

N. 57° 29' W.

52 J. W. AfaUet— Crystalline form of Sipylite.

Art. IX. — On Uie Crystalline form ofSipylite; by

J. W. Mallet.

In the original description* of the mineral in question from
the allanite locality in Amherst Co., Va., very little could be
said about the crystalline form, as but a few imperfect faces
had been met with. I have recently obtained some additional
specimens, most of them irregularly shaped nodules imbedded
in allanite, but fortunately among them one nearly complete
detached crystal, broken into two parts indeed, but these fitting
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 Al (over summit)=53° o'
(Hence O a. 1=116° 30')
1 a1 (adjacent pyramidal) =100° 45'
1 zv 1 (basal)=127°0'

These measurements show a close relation to fergusonite,
for which

O/s 1=115° 46'

1^1 (pyramidal) =100° 54'

1A1 (basal)=128° 28'

The relation in form between fergusonite and tapiolite and
xenotime on the one hand, and scheelite, stolzite and wulfen-
ite on the other has been pointed out by Rammelsberg.f
The angles for sipylite and for fergusonite are connected
with those of xenotime if a of the two former be taken =2a of
the latter, and this,J as well as Rammelsberg's analysis of
fergusonite, supports the view expressed in my former paper
that sipylite is an ortho-niobate — R", M% Oe — containing basic
hydrogen.

The sipylite crystal shows distinct cleavage parallel to 1. It
is fully identified with the mineral originally examined by its
general physical characters. The sp. gr. =4*883 at 16° C. ;
formerly found, 4*887 at 12°*5, and 4*892 at 17°*5.

Univ. of Virginia, May 21, 1881.

♦This Journal, 397, Nov., 1877. f Jour. Chem. Soc., 189, March, 1812.

\ Taking the usual, and probably correct, view of xenotime, that it is an ortho-
phosphate. But no great weight can bo 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 Dictyophyton and its
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 ocelli's 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 expressed, " that they are Algae 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 described,
given on Plates 3 to 5A of the above cited work, it will be
seen that these bodies are more or less elongated tubes, straight
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 threads
between the coarser ones. When the specimens, which are
casts or impressions in sandstone,. are carefully examined, it is
found that these threads are not interwoven with each other
like basket work, or like the fibers of cloth, nor do they unite
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 directions, while the
entire thickness of the film or substance of the body 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 character. This

Eeculiar net-like structure does not seem to be that of any
nown plant, nor does their nodose, annulated, cylindrical or
often sharply longitudinally angular form, with nearly perfect
corners, indicate a vegetable structure ; moreover, it is not a
feature likely to be retained in a soft, yielding vegetable 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 indicate a substance of consider-
able rigidity and firmness of texture.

In examining the structure of Euphctella 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 H. P. Whitfield — Structure of Dictyophytoni

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 Euplectella 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,

As yet we have no positive evidence of the nature of the
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
strong markings left in the rock, and the almost perfect reten-
tion of their original form, that they were of a siliceous nature.
Still, in this opinion I may be mistaken, and it must be left
for future discovery to determine ; but that they were of the
nature of sponges and not of plants I feel very confident.

The form given by Professor Vanuxem in the Geological
Report of the Third District of the New York Survey, and
also figured in the 16th Report above cited, I think would
also better conform to this idea than to that of v, vegetable
origin, although its broad flattened bands may be something
of an objection.

The name Hydnoceras was originally applied by T. A. Conrad
to designate a species of this genus (Jour. Acad. Nat. Sci.
Philad., vol. viii, 1st series, p. 267), but was discarded on
account of its objectionable signification, though if the view
here suggested prove correct the later appellation is almost as
objectionable.

O. C. Broadhead — Carboniferous Rocks of Kansas. 55

Art. XL — The Carboniferous Rocks of Southeast Kansas ; by

G. C. 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, connecting with similar measures in Missouri.

West of the Verdigris Eiver the Upper Coal-measures also
extend but soon disappear beneath the " Permian." The main
productive Coal-measures of Southeast Kansas lie south of
Miami County. Passing from Paola southwestwardly to Green-
wood County, we find only a thin coal-seam occasionally 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 exoosure of coal
belonging to the Carboniferous formation. In tne western part
of Woodson and in Greenwood County 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 Fusuliria cylindrica and nearly 200 feet more of sand-
stone, with other limestone beds above, containing well known
Carboniferous fossils, including Fusulina cylindrica. and Choztetes.
The step now is more rapid to the "Permian."

Entering the State near the line of Cowley and Chautauqua
counties, we find ourselves upon a long dividing ridge extend-
ing and well defined for seventy miles northwardly.

This 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 <r. C. Broadhead — Oirtoni/erous Rocks of Kansas.

highest ground east of Arkansas and Wain at Yallev. On the
west side of this ridge the descent is gentle and scarcely per-
ceptible, being 3**> feet in 25 miles to the Arkansas Valley.
On the east the descent is more abrupt, the ridge presenting
ragged walls of limestone separated by shaly slopes, and the
hills descend 350 fee: 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.
The approaches to this ridge from Fall River Valley is by a
succession of terraces or plateaus of upper Carboniferous rocks.
At Twin Falls we are on a lower terrace elevated about 1000
feet above the sea. The . second terrace is reached six miles
south west wardly 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 mainlv shalv 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 beneath the Permian. The
Permian or Permo-carboniferous of the u Flint Hills" include a
total of about 500 feet thickness. The following section I have
condensed from several taken within twentv miles.

1. Sixty-two feet including chert layers with thin beds of
shaly drab-colored limestone : the highest rocks seen in " Flint
ridges/' observed Bryozoa with Athyris subtilita, Productus
costatus and Hemipronites crenistria.

2. Ninety feet mostly thin limestone layers chiefly disinte-
grating on exposure.

3. Seven feet bed of porous chert resting on limestone.
Pinna peracxita found even- where. A Phillipsia was also ob-
tained.

4. Eightv-five feet chief! v 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 Fisiulipora (?), Productus Xebrascensis, P. semireticulatus,
MeekelUi striaticostata, Chonetes graculifera, Terebratula bovidens,
AOtyris subtilita, Yoldia subscitula, Schizodus Rossicus, Myalina
perattenuata, Hemipronites crenistria, Avicidopima Americana, and
other known Upper Carboniferous fossils.

5. Five feet of bluish drab and sometimes buff limestone
containing Eumicrotis Bawni, Myalina perattenuata, Aviculopec-
ten occidmtalis. [This bed is easily recognized wherever seen.]

Q. C. Broadhead — Carboniferous Rocks of Kansas, 57

6. Ten feet red and green shales.

7. Fifty-tbree feet beds shale, with some beds of limestone
very good for building purposes.

8. Twenty-eight fe,et limestone abounding in Fusulina cylin-
drica ; the middle layers contain blue chert full of Fusulince
showing the structure very finely.

9. Twenty-eight feet of sandstone.

10. Four feet gray limestone containing Productus semiretic-
utatus, Alhrisma granosa, A. subcuneata, Pinna per acuta, Nau-
tilus capax, etc.

The last bed I regard as the base of the Permian.

Other fossils obtained at the several localities include Alio-
risma subelegans, A. Topekaensis, Macrodon — , Nautilus occiden-
talism Murchisonia — . Although these fossils seem at home in
the Permian, I have obtained them also, with scarcely an
exception, from known Upper Coal-measure rocks of Missouri:
in fact most of them have been obtained from the rocks of
Kansas City.

The limestones of the Permian have been extensively 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 soft 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 dip westwardly of not less than 25 feet per
mile. Assuming this to be correct we may be safe in saying
that there are 1500 feet total thickness of Permian beds in
southern Kansas. In the counties of Butler, Cowley, 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 grouped together as can certain
other strata of other formations.

The only marked difference is this : 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.

The group of the Permian Mountains forms an interesting
study ; the strata are easily traced and the scenery afforded is
very fine and views extensive.

The above is an abstract of a more detailed paper.

58 K W. Hilgard— Later Tertiary of the Gulf of Mexico.

Art. XII. — The Later Tertiary of the Gulf of Mexico ; by E.
W. Hilgard, Berkeley, CaL With a map (Plate HI).

Is view of the late publication of the Coast Survey chart
of soundings in the Gulf of Mexico, and of the observations
of Dr. Eugene A. Smith on the Geological Formations of Florida
(this Journal, April, 1881). I desire to summarize briefly the
facts upon which my hypothesis of a temporary and partial
isolation of the Gulf from the Atlantic Ocean during the later
portion of the Tertiary period, is based. I shall add thereto
some additional facts that have since been brought to my
knowledge, concerning the more remote portions of the group
of deposits to which, from its most accessible and representa-
tive exposure at the town of Grand Gulf, on the Mississippi
Biver, I have given the name of ik Grand Gulf Group."

So far as known at present, the fc* Vicksburg" group of ma-
rine marls and limestones, containing only extinct forms of
life and therefore according to usage accounted "Eocene,"
closes abruptly the Tertiary series of marine fossiliferous de-
posits, on the entire mainland border of the Gulf of Mexico,
from Florida to the Rio Grande. In the portions lying near
the main axis of the Mississippi trough, the uppermost strata
of the Vicksburg rocks show, by the constant intercalation of
laminated clays and lignite beds and seams with the marine
deposits, that the sea was shallowing more and more ; and the
highest portions are everywhere in the State of Mississippi
characterized by a great prevalence of gypsum seams, and are
often strongly impregnated with magnesian salts, as well as
with common and Glauber's salts. The same is true of the
lower portions especially, of the overlying Grand Gulf rocks;
so that throughout the region occupied by the latter, few well-
waters obtained within them are fit for daily use, and many
are strongly mineral.

At their lines of contact, the Vicksburg and Grand Gulf
rocks consist almost throughout of lignito-gypseous, laminated
clays, passing upward into more sandy materials : they are not
sensibly unconformable in place : but while the Vicksburg
rocks show at all long exposures a distinct southward dipVrf
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 or
subsidences have caused them to clip, sometimes quite steeply,
in almost any direction. They, however, lie high on the hill-
tops between the towns of Vicksburg and Grand Gulf, and
disappenr at the water's edge near the Louisiana line, under
the gravel beds of the Stratified Drift.

K 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
represent, on the northern border of the Gulf, the entire time
and space intervening between the Vicksburg epoch of the
Eocene, and the Stratified Drift. Their total thickness does not
exceed, if indeed it reaches, 250 feet. In the absence of deep
borings on the Grand Gulf territory, this can be best observed
on the northern edge of the formation, where it forms high
ridges, from which there is an abrupt descent, northward, into
the level prairie country of the Vicksburg territory.

From these rocky hills, which form sharp ridges diagonally
across the States of Mississippi and Louisiana, and a portion
of Texas, and which present even in small profiles an indefi-
nite variety of more or less laminated claystones, clay-sand-
stones, or sometimes siliceous sandstones, there is a gradual
descent southward, and a gradual increase of clayeyness and
decrease of hardness, until, in the seaward portions of the for-
mation, we find chiefly stiff, blue or green, and more or less
massy clays. In these, at a certain level, there occurs a stra-
tum copiously traversed by calcareous seams ; and smaller
ones occur at higher levels. In one such outcrop, on Pearl
River, I found the only vestige of a zoogene fossil thus far
seen in the entire formation ; it is recognized by Professor
Marsh as a fragment of a turtle shell. Apart from this, my
most patient search, in hundreds of localities, has failed to pro-
duce any definite fossil form ; even the leaves associated with
the lignite seams being so ill preserved as to be unrecognizable.

While in Mississippi and Louisiana the calcareous facies is
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. This state of
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 bv 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 M W. Hilgard — Later Tertiary of the Gulf of Mexico.

line of Florida (where according to Dr. Smith the Vicksburg
rocks reach the coast) to the Eio Grande ; attaining a width of a
little over a hundred miles in the axis of the Mississippi
trough, southward of Vicksburg, aud thence narrowing rapialy
to an average width of forty miles in Texas, and crossing the
Eio 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 is
exemplified in the Quaternary beds of Cote 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 ligni to-gypseous
facies.

The first objection disappears, as just stated, in the south
Texan portion of the area. Curiously enough, precisely the
same thing happens in the case of the Quaternary strata of the
Texan coast, whose direct connection with the '* Port Hudson"
strata of Mississippi and Louisiana is indisputable. Specimens
collected by Dr. Loughridge on the coast at Port Lavaca, and
according to him fairly representative of the general facies of
the shore in that region, show that the subordinate feature of
the fresh-water limestone ledges seen on the Louisiana coast,
has here become quite prevalent. But here, also, fossils are
very scarce at least, for he was unable to find a single recog-
nizable form at any of the outcrops examined by him. It
would thus seem as though we were driven to account for the
same state of things in the Quaternary as well as in the later
Tertiary period — the absence of marine deposits and fossils,
where on ordinary grounds of probability wfe should expect to
find them ; and their replacement by fresh- or brackish- water
deposits, with fossils macerated to unrecognizability.

To complement this statement of facts, while unable to find

E. W. Hilgard — 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 nave them pointed out. It seema almost
incredible that so obvious a feature of a seaport so frequently
visited by Americans should not have been better observed,
even accidentally.

The geology of Yucatan is involved in equal obscurity.
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 fossi life rousTertiaries, 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
observers have taken the futile pains of comparing these beds
with European Tertiaries only ; while Mr. Gabb, true to the
time-honored idea of making as many distinct species as pos-
sible, has in his descriptions of the Tertiaries of Santo Domingo
given us the impression of the creation of a new fauna spe-
cially for that island, with scarcely an attempt to identify the
variations of forms there found, with those already known from
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 glory
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
unpromising task of a discussion and comparison of what is
known 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
not 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 sfnce 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 R W. Hilgard— Later Tertiary of&e Gulf of Mexico.

a different aspect when viewed by the light now afforded by
oar 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
ocean basin not separated from the central part of the North
American Continent by areas of disturbance and mountain-
making, the Gulf of Mexico deserves first and chief attention,
as the reference plane from which the oscillations of that cen-
tral portion must be measured : while its shores are the uro-
meters upon whicK those movements can alone be found
recorded. It would seem as though the reading and exact
understanding of that record should have been the first thing
to be done in attempting to unravel the Tertiary and Quaternary
history of the country lying between the Alfeghenies and the
Bocky Mountains : just as 'the measurement of a base line is
the first in a geodetic survey. The stratified drift of the South
alone renders intelligible the succession of events that must
have occurred at the North : it is only on the shores of the
Gull that the question whether the Glacial epoch of the interior
was one of elevation or of depression, together with the mea-
sure of these, can bo finally determined. I have vainly sought
for assistance in this wide and important field, until quite
lately, when the explorations of Smith and Loughridge, under
the auspices of the United States Census, have furnished im-
portant additional data.

The 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
clavs with onlv 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
clayey materials largely intermixed with lignito-gypseous beds.
The succeeding "Yicksburg'' stage is more of a deep-sea
character, and its inconsiderable thickness in Mississippi and
Louisiana speaks of a short duration of the epoch, at the end
of which the lignito-gypseous feature again appears.

H. W. Ililgard— Later Tertiary of Hie Oulfof Mexico. 63

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, I am informed by Dr. Loughridge, is marked by
numerous and very long trap dykes, running paraHel to it in
the metamorphic region of the State. As Dr. Smith has ob-
served, there is a distinct ridge or u 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 Eio Grande, and
doubtless beyond. Toward the east, these beds " run out" on
or about the Perdido Eiver, 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 exaqtly in the prolongation of the edge of the great
submarine border plateau outlined by the u 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
the Gulf shores should be elevated to the extent of 600 feet all
around, we should find it lined with a wall of "Vicksburg"
limestones. But however that may be, the existence of this
great shelf furnishes, as it seems to me, an explanation of the
"Grand Gulf" rocks on the mainland.

I take it for granted that the oscillations in the axis of the
Mississippi Valley are proven* to have been greater than on
either side of the same ; in other words, that it is, and has
been, 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 E. W. Eilgard — Later Tertiary of the Oulf 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
epoch, 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,
whose waters would be kept perceptibly freshened by the con-
tinental drainage, especially in the axis of the Mississippi
Valley, even in the present condition of the straits of Yucatan
and Florida. If, however, we suppose the bottom of the
latter to have participated in the elevation to a greater or less
extent, sensibly lessening the oceanic circulation, the freshening
of the border waters may readily be supposed to have been
such as to render very precarious the existence of either a
marine or fresh-water fauna; thus accounting for the re-
markable dearth of fossil forms in the Grand Gulf strata. An
occasional cessation of the movement, or other local cause,
might for a time allow of the existence of limited areas of
abundant life, such as are indicated by the subordinate calcare
ous basins with, presumably, a macerated fauna. That these
indications should increase as we approach the Yucatan chan-
nel, that is, along the ancient coast of Texas, is to be expected ;
and it may be fairly presumed, that, farther to the south, near
Vera Cruz and beyond, we shall hereafter find the purely
marine equivalents of the Grand Gulf rocks. That these rocks
should have an exceptional character, that of coarse sandstones,
near the axis of oscillation, is intelligible enough. It appears,
however, that the sandstone character, which in Mississippi
disappears about half way across the State, continues in Texas
as far south as Indianola, and probably even to the Eio Grande,
where, as previously mentioned, the formation seems to widen
out even more than is the case in Mississippi. It would thus
appear that Texas has participated, far more than Alabama, in
the oscillations of the Mississippi Valley.

It should not be forgotten that in the latter, we find the
Grand Gulf rocks, still capped by drift beds, at elevations of
at least 500 feet above the Gulf. During the highest elevation
of the Glacial epoch, therefore, they must have risen to over
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 u Terrace" period of
erosion, by which the present channel of the Mississippi Eiver
was formed.

The map of soundings exhibits very strikingly the analogy

1h*BAMiWft>

J. L. Campbell — Dufrenite from Rockbridge County, Va> 65

of the relation of the two peninsulas of Florida and Yucatan
to the Gulf Stream on the one hand, and the basin of the Gulf
on the other. The eastern shores of both fall off steeply into
deep water, while the gulfward shores are bordered by the
shelf, 100 to 130 miles in width, which breaks off into deep
water at the 100-fathom line. It would thus seem a priori
probable, that both peninsulas were elevated at the same time
and to a somewhat similar extent as regards their lowlands;
and if so, this event cannot but have exerted a considerable
influence in diminishing the volume of the Gulf Stream pass-
ing inside of Cuba, and in greatly restraining the peripheric
Gulf current. Such events could not have failed to exert some
influence upon the climate of the regions concerned, as well as
upon the nature of the Gulf-border deposits.

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 far toward the elucidation.
But any such exploration should be made, not with a view to
the discovery and naming of new fossils, but with that of
working from the base-line of the well-observed facts and
regions toward those yet to be observed, and of unifying that
which of necessity must have been evolved as a unit. That
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 unfortunately true. Nowhere would a richer field
reward the labors of the faithful worker. The lime for this
has certainly come — but where is the man?

Art. XIII. — On Dufrenite from Rockbridge County, Va. ; by

J. L. Campbell.

During the summer of 1875, a number of specimens of iron
ores from the Blue Eidge range in Eockbridge County, V.sl.,
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. When
broken open, the newly exposed surface showed a radiated,
coarsely fibrous structure, with a rather dull silky luster, and a
dark greenish brown (almost black) color. Where the surfaces

Am. Jour. Sol— Third Series, Vol. XXII, No. 127.— July, 1881.

66 J. L. Campbell — Dvfrenite from Rockbridge County, Viz.

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 limonite — the original structure being preserved.

The unaltered part of the mineral reduced to fine powder
was of a light yello wish green color. When 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 cpld. 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 ;
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:

Phosphoric acid (as pentoxide) 31'761

Ferrous oxide 6*144

Ferric oxide ' 50*845

Alumina _ 0*212

Manganous oxide ..._.. 0*403

Lime _ 1*124

Magnesia _ 0*762

Water lost at red heat___ 8*531

Insoluble silica — very fine sand 0*115

99-89T

Some samples more recently tested left but a trace of silica
when dissolved in hydrochloric acid, while others gave less lime
and magnesia, and more alumina than the foregoing analysis
indicates. Still, there is no reason to doubt that the great
bodv of the mineral mass is u dufrenite " which hitherto seems
rarely to have given identical results in the hands of any two
analysts.

Geological position. — On visiting the locality where the du-
frenite is found, it was ascertained to be about ten (10) miles
east of Lexington, Va., near the crest of what is locally known
as " South Mountain " — one of the many primordial broken
ridges that skirt the northwestern base of the main Blue Ridge.
It is in the ferriferous bed of shales and shaly sandstones that
here constitutes the upper member of the primordial or Pots-
dam, group. Its position will be readily understood by refer-
ence to a profile section of the Blue Ridge and Great Valley,
published in this Journal for July, 1879, vol. xviii, page 19.
That section cuts the range only a few miles to the southeast
of Irish Creek, while the bed of dufrenite is a little to the
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 If its upper limit would very well indicate the
geological locality of the mineral deposit The strata here,
however, have a much more moderate dip than at the point cut
by the section.

A rude shaft or pit was found to have been sunk 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 depth
of ten or twelve inches, as far as could be determined in the
presence of a considerable caving in of the old shaft.

This 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, Lexington, Va., May, 1881.

Art. XIV. — Turquois of New Mexico; by B. Silliman.*

The existence of turquois, a comparatively rare gem. in
New Mexico, is a fact long known. The chief locality is at
Mt. Chalchuitl, in Los Cerillos, about twenty-two miles south-
west of the ancient town of Santa F6, the capital 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 Sciencef 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 locality, since
it has been laid open in the old workings and thus rendered
accessible to observation by the recent explorations of Mr. D.
C Hyde.

The Cerillos Mountains have recently come into notice from
the partial, and as yet superficial, exploration of very numer-
ous mineral veins which are found to intersect them, and which

* Read before the American Association for the Advancement of Science,
Boston, August, 1880.
fThis Journal, 2d Ser., xxv, 27.

68 B. Silliman — Turquois of New Mexico.

carry 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. These 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-
cans gave to the turquois, its much valued mineral), the
summit of which is about 7,000 feet above tide, and is there- i
fore almost exactly on a level with the Plaza of Santa F6, \
across the vallev of the river of that name, to the northeast
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-
chuitl 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 j
most conspicuous and important. In this yellowish-white and "
kaolin-like tufaceous rock the turquois is found in thin vein lets
and little balls or concretions called " nuggets," covered with
a crust of the nearly white tuff, which within consist generally,
as seen on a cross fracture, of the less valued varieties of this
gem, but occasionally afford fine sky-blue stones of higher
value for ornamental purposes. Blue-green stains are seen in
every direction among these decomposed rocks, but the tur-
quois in masses of any commercial value is extremely rare,
and many tons of the rock may be broken without finding a
single stone which a jeweler, or virtuoso would value as a
gem.

The observer is deeply impressed oir inspecting this locality
with the enormous amount of labor which in ancient times has
been expended here. The waste or debris excavated in the
former workings covers an area, which the local surveyor
assured me extends by his measurement over at least twenty
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 region

B. SUKman — Turquoa 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.

The accompanying vertical section of the mountuin from

east to west will give a good idea of the old workings, and of

the shafts and tunnels projected and partly carried out by Mr.

Hyde. Theirregular openings, named by Mr. Hyde "wonder

caves " and the " mystery," are the work of the old miners, and

the whole hillside from the flag-staff to the "mystery "was

worked out by them also. It was this sharp slope of the

mountain which fell In these chambers, which have some

extent of ramification, were found abundantly the fragments

of their ancient pottery, with a few ent;re vessels, some of them

of curious workmanship, ornamented in the style of color so

familar in the Mexican pottery. Associated with these were

numerous stone hammers, some to be held in the band and others

swung as sledges, fashioned with wedge-shaped edges and a

groove for a handle. A hummer 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 Gerro
d'Oro and other Cerillos trills. With these rude tools and
without iron and steel, using fire in place of explosives, these
patient old workers managed to break down and remove the
incredible masses of these tufaceous rocks which form the
mounds already described.

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 being that
near Columbus District in Nevada, discovered by Mr. J. E.
Clayton ; and this is not yet worked.

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
quantity 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 20'5=100-?.

Evidently the decomposition of the feldspar of the trachyte
furnishes the alumina, while the apatite, or phosphate of lime,
which the microscope detects in thin sections of the Cerillos
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.

The inspection of thin sections of the turquois by the micro-
scope, with a high power, detects that the seemingly homogene-
ous mass of this compact and non-crystalline mineral consists
of very minute scales, nearly colorless, having an aggregate
polarization, and showing a few particles of iron oxide.

The rocks in which the turquois occurs are seen, by the aid
of the microscope and polarized light, in thin sections, to be
plainly only the ruins, as it were, of crystalline trachytes ; they
show fragments of feldspar crystals, decomposed in part into a
white kaolin-like substance, with mica, slag and glassy grains,
and quartz with large fluidal enclosures, looking like a second-
ary product There is considerable diversity in aspect, but
they may all be classed as trachyte-tuffs and are doubtless
merely the result of decomposition, as already indicated, of the
crystalline rocks of the district along the line of volcanic fis-
sures. 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.

SCIENTIFIC INTELLIGENCE.

I. Chemistry and Physics.

1. On Free Fluorine in Fluor Spar. — The cause of the peculiar
odor possessed by the dark violet fluor spar of Wolsendorf has
been much discussed. Schafhautl ascribed it to the presence of
calcium hypochlorite, Schrotter to ozone, Schonbein to antozone,
and Wyrouboff to a hydrocarbon. Loew, noticing the similarity
of the odor on freshly fractured surfaces to that of chlorine, con-
cluded that it was due to the presence of fluorine formed by the
dissociation of some foreign fluoride present in minute quantity.
The ozone theory was given up by Schrotter when he found that
the odor was not destroyed by a heat of 310°. Moreover, he
showed an alteration in this odor when the mineral was ground
with potassium hydrate solution, and proved that an odor resem-
bling that of sulphur chloride was produced when it was rubbed
in a mortar with sulphur. Chlorine was separated from sodium
chloride by it and iodine from potassium iodide. To test
his fluorine hypothesis, Loew ground a kilogram of W5lsen-
dorf fluor spar with water containing ammonia, using small
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, covered with
a watch glass, kept at 40° to 50° for a long time. On exam-
ining the glass it was found to be very considerably corroded.
Since fluor spar is not entirely insoluble in water, the experiment
•was repeated, using the inodorous mineral. The result was so
exceedingly feeble as to dispose entirely of this objection to the
former result. Since these dark radiated varieties of fluorite
contain cerium, the author thinks a eerie fluoride is the source of
the free fluorine, by dissociating into cerous fluoride and fluorine,
analogous to the decomposition of manganese tetra-chloride at
ordinary temperatures. — JBer. JBerl. Ghem. Ges., xiv, 1144, May,
*&81. G. F. B.

2. On Arsenobenzene. — Azo-benzene C8H5N=NCflH6, has long
*>een known, and phosphobenzene C6H6P=PCflHB has recently
*>^en discovered. The corresponding compound of arsenic, arseno -

72 Scientific Intelligence.

benzene CeH6As=AsC6H6 has now been obtained bv Michablis
and Schultze. For this purpose phenyl-arsenous oxide 06H§AsO
was acted upon in alcoholic solution by reducing agents, prefera-
bly phosphorous acid. No change takes place in the cold but on
heating nearly to boiling the reaction takes place and the mass
solidifies in crystals. On filtering, washing with hot alcohol and
drying in a vacuum over sulphuric acid, the arsenobenzene is ob-
tained pure, in the form of pale yellow needles, difficultly soluble in
alcohol, insoluble in water and ether. Chloroform, carbon disul-
phide, and benzene dissolve it easily, but the solution resinifies
readily. Beautiful crystals are obtained on cooling from solution
in hot xylene. Chlorine unites with it directly to form phenyl-
arsenous chloride. It fuses at 196° to a yellow liquid, and decom-
poses above this, evolving triphenylarsme and metallic arsenic.
Phenyl-arsenous iodide when reduced gives arseno-iodo-benzene
CflH5lAs - AsICBHB. Naphthalene acts similarly, an arsenonaph-
thalene C10H<lAs=A8C10H7 being produced by the reduction of
naphthyl-arsenous oxide by phosphorous acid. — Ber. Deri. Chem.
Ges. xiv, 912, Apr., 1881. G. F. B.

3. On the Transformation of Dextrose into Dextrin. — Some
years ago, Musculus observed that when dextrose was dissolved in
concentrated sulphuric acid, a new body was obtained which was
probably a dextrin. The recent experiments of Gautier, have led
Musculus in conjunction with Meyer, to re-examine this subject.
Twenty grams of pure dextrose was melted in a calcium-chloride
bath ; after cooling thirty grams of concentrated sulphuric acid
was added in four or five successive portions, the whole being
stirred with a thermometer, the temperature being allowed to rise
to 60° and the mixture to become brown. Eight hundred parts
of absolute alcohol were then added, the solution filtered and
allowed to stand for eight days. The abundant precipitate was
collected on a filter and washed, first with cold and then with
boiling absolute alcohol till all traces of acid were removed. It
was then dried. In this way there were obtained ten grams —
half the dextrose used — of a perfectly white amorphous powder,
hygroscopic but not deliquescent. It contains alcohol not remov-
able by drying over sulphuric acid for months or by a heat of
100°. By solution in water and distillation 9*3 percent of alcohol
was obtained. Heated to 110°, the alcohol evaporates and the
remaining powder is extremely deliquescent. On analysis it gave
numbers agreeing with the formula C18Ha8014. Hence the first*
powder was a combination of this with a molecule of alcohol,
C18Ha8014. CaHflO, which requires 8*9 per cent of alcohol. This,
when decomposed by water, the alcohol removed by evaporation
and the residue dried over sulphuric acid, gives a body whose
analysis agrees with the formula CflH10O6. When therefore the
alcohol in the above formula is replaced by water the formula be-
comes C18H88014 . HaO or (C8H10OB)3. This hydrated body pos-
sesses all the physical, chemical and organoleptic properties of a
dextrin. It is amorphous, yellowish, very soluble in water, of a

Chemistry and Physics. 73

flat sweetish taste, is not colored by iodine, is precipitated by
alcohol from its aqueous solution, reduces only very feebly Fehling's
test, rotates to the right the plane of polarized light [«]=-f-131 to
+ 134°, does not ferment with yeast, is not saccharified by dias-
tase, is converted into dextrose by prolonged boiling with dilute
sulphuric acid, and has the diffusibility of a dextrin, being nearest
to the ^-dextrin of Musculus. — Bull. Soc. Ch., II, xxxv, 368, Apr.,
1881. G. F. B.

4. On Pentathionic Acid. — Lewes has satisfactorily established
the existence of pentathionic acid. Continuous currents of hydro-
gen sulphide and sulphurous oxide gases were passed, according
to Wackenroder'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 10 c.c. 023, 0*227 and 0226 of sulphur. On titrition, 1
c.c. neutralized 0*01457 gram KaO, equal to 00 12 gram potas-
sium ; thus giving 2 : 4#55 for the ratio of K : S, and suggesting the
presence of an acid haviug more sulphur than the tetrathionate.
Having 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 only
half of it. On filtering after standing twenty-four hours, a clear
solution was obtained which was placed in a vacuum over sulphuric
acid. After 18 days a crop of fine needle-shaped crystals was
obtained which proved on analysis to be barium tetrathionate.
In a few days a second crop of crystals was obtained consisting
of thin square plates mixed with a few oblong rectangular crys-
tals, which gave on analysis numbers between those of tetra- and
pentathionate, probably a double salt. A third crop of very
small oblong rectangular crystals was obtained which gave on
analysis uumbers agreeing with the formula BaSB06(HaO)8. The
salt is soluble in cold water and if not too concentrated the solu-
tion may be boiled. The reactions of the solution are given. By
the same process, three potassium salts of pentathionic acid were
obtained ; one in semi-opake, probably rhombic crystals KaS6Ofl
(HaO)a; another in small and apparently monoclinic crystals,
having one molecule of water of crystallization; and a third in
very small, short prisms, which is the anhydrous pentathionate
KaS6Ofl. These salts may be easily prepared as they are much
more stable than the barium salt. They are distinguished from
the corresponding tetrathionates by the fact that they give an
immediate precipitate of sulphur on adding an alkali hydrate. —
J. Chem. Soc, xxxix, 68, March, 1881. g. f. b.

5. Photographies: A Series of Lessons, accompanied by Notes,
on all the Processes xchich are needful in the Art of Photography y
by Edw. L. Wilson. 8vo, pp. 352. Philadelphia, 1881. — Mr.
Wilson has sought in this book to produce a hand-book for the
professional as well as for the amateur photographer. The plan
is somewhat novel. After giving in a clear and satisfactory way,
on the upper half of the page, the matter culled from his own

74 Scientific Intelligence,

experience, he prints in smaller type, on the lower half, quota-
tions bearing directly on the subject in hand, and taken from the
best authorities known. In this way the opinions of over two
hundred authors have been secured to the reader. The science
and the art of photography is given in twenty-seven lessons, each
treating of one branch. I'he first of these on the treatment of
the subject is an excellent discussion of the esthetic in photog-
raphy, illustrated from the masters in art. Then follows the
technique of the wet plate process in all its parts. The dry plate
process follows this, and then some of the more recent photo-
type processes, and the book closes with some useful practical
suggestions. The work appears to be a great success in its man-
ner as well as its matter. It will certainly become the standard
book on photography in this country. G. f. b.

6. Conservation of Electricity. — In a memoir by M. G. Lipp-
mann, presented to the French Academy by M. Jamin, the author
maintains that the quantity of matter and the quantity of energy
are not the only magnitudes in nature which remain invariable; the
quantity of electricity in the universe is also invariable. The distri-
bution of electricity can change, but the quantity of free electricity
never varies. The sum of the quantities of free electricity is in-
variable since the total variations of the charges is always equal
to zero. Let x and y be two independent variables upon which
the quantity of electricity which a body receives depends ; x can
be, for example, the potential which the body acquires, y its
capacity, or a quantity proportional to the capacity. Let dm be
the quantity of electricity received by a body when x is increased
by dx and y by dy ; one can then write dm =Pcfc-|-Qtfy, in which
P and Q are two functions of x aud of y. The principle of the
conservation of electricity is expressed 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,
A and B. Let a and b be the simultaneous variations of these
two portions. In virtue of this principle of the Conservation
of Electricity, we must have a-\-b=.0. When A passes over a
closed cycle, that is to say, when its final state corresponds to its

initial one, a=0 and#=0. We can then write I dmznO. In
order that I dm may be zero for every closed cvcle, it is "neces-
sary that dm shall be an exact differental, or ^=-=z-r— . In this
J dy dx

manner we can write the analytical expressions for the general
principle of the Conservation of Electricity. — Comptes JKendus,
No. 18, May 2, 1881. j. t.

7. Inverse Electromotive force of the Voltaic arc. — M. J. Jamin
corroborates the statements of Si. LeRoux in regard to the
inverse electromotive force which arises from the carbon points
of the electric lights. This electromotive force is nearly equiva-
lent to that of ten to fifteen Bunsen 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 maintaining the light. Thus it is
difficult to produce two or a greater number of arcs in the same
continuous current, since it is necessary to overcome the inverse
electromotive force of each light. This fact is an objection to the
use of batteries, continuous current machines, secondary batteries
like those of Plante" or of Faure. The conditions, however, are
very different with the use of alternate current dynamo-electric ma-
chines ; for with a certain speed of alternation the effect of the
inverse electromotive force is a minimum. The difference of tem-
perature of the carbon points determines the strength of the
inverse electromotive force, and when this difference of tempera-
ture tends to disappear as it does when alternate currents are
employed, the inverse electromotive force is very much dimin-
ished.— Comptes Rendus\ No. 18, May 2, 1881. j. t.

8. Stellar Photography. — In a letter addressed to M. A. Cornu,
H. Draper relates that he has succeeded in photographing, after
an exposure of one hundred and forty minutes, the stars in the
nebula of Orion, which can be represented in size by the numbers
14-1, 14*2, 14'T, according to the scale of Poyson. Photography
has thus secured images of stars nearly at the limit of visibility
in a telescope of nine inches aperture. It seems, therefore, not
improbable that stars which are invisible to the eye in a tele-
scope of this size can be photographed. — Comptes Rendus, No. 16,
April, 1881. j. t.

9. Weather Warnings. — Professor Balfour Stewart, in a
lecture delivered at South Kensington, April 29, spoke of the
probability that British magnetical weather may be followed after
five or six days by corresponding meteorological weather. From
a preliminary trial, Professor Stewart believes that it may be
possible to forecast meteorological weather some five or six days
by means of the variations of the magnetic elements. — Nature,
May 5, 1881. j. t.

1 0. Storing of Electricity. — M. Faure has modified the second-
ary battery of Plante by coating the lead plates with a covering
of minium. The sheets of lead are separately covered with
minium and rolled together in a spiral with a layer of felt be-
tween, and are then placed in a vessel of sulphuric acid and
water. When 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. Reynier, one of these spiral cells weighing 75
kilograms can store up energy sufficient to furnish one horse
power for au hour.— -Nature, May 19, 1881. j. t.

II. Geology and Natural History.

1. Sketch of the Geology of British Columbia ; by George M.
Dawson, D.S., A.R.S.M., F.G.S. — British Columbia includes a
certain portion of the length of the Cordillera region of the west
coast of America, which may be described as consisting here of

76 Scientific Intelligence.

four parallel mountain ranges rnnning 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 next, to the northeast, is the
Coast or Cascade Range, a belt of mountainous country about 100
miles in width. This is succeeded by the interior plateau of
British Columbia, relatively a depressed area, but with a height
of 3000 to 3500 feet. To the northeast of this is the Golden Range,
and beyond this the Rocky Mountains proper, forming the western
margin of the great plains of the interior of the continent.

Tertiary rocks, which are probably of Miocene age, are found
both on the coast and over the interior plateau. They con-
sist on the coast of marine beds, generally littoral in character,
which are capped, in the Queen Charlotte Islands, by volcanic
rocks. The interior plateau has been a freshwater lake, 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.

Cretaceous rocks from the age of the Upper and Lower Chalk
to the Upper Neocomian, and representing the Chico and Shasta
groups of California, occur on Vancouver and the Queen Charlotte
Islands. Beds equivalent to the Chico group yield the bitumin-
ous coals of Nanairno, while anthracite occurs in the somewhat
older beds of the Queen Charlotte Islands. Within the Coast
range the Cretaceous rocks are probably for the most part equiv-
alent in age to the Upper Neocomian. The Cretaceous rocks are
of great thickness, both on the coast and inland, and include
extensive contemporaneous volcanic beds.

The pre-Cretaceous beds had been much disturbed and altered
before the deposition of the Cretaceous, and their investigation is
difficult. On Vancouver Island, beds probably Carboniferous in
age include great masses of contemporaneous volcanic material,
with limestones, and become altered to highly crystalline rocks
resembling those parts of the Huronian of Eastern Canada. In
the Queen Charlotte Islands these beds also probably occur ; but
an extensive calcareous argillite formation is there found, which
is characterised by its fossils as Triassic.

The Coast Range is supposed to be built up chiefly of rocks
like those of Vancouver Island, but still more highly altered, and
appearing as gneisses, mica-shists, &c, while a persistent argilla-
ceous and slaty zone is supposed to represent the Triassic argillites
of the Queen Charlotte Islands.

The older rocks of the interior plateau are largely composed of
quartzites and limestones ; but still hold much contemporaneous
volcanic matter, together with serpentine. Carboniferous fossils
have been found in the limestones in a number of places. The
Triassic is also represented in . some places by great contempo-
raneous volcanic deposits with limestones. >

In the Golden Range, the conditions found in the Coast Range
are supposed to be repeated ; but it is probable that there are

Geology and Natural History. 77

here also extensive areas of Archaean rocks. Some small areas of
ancient crystalline rocks, supposed to be of this age, have already
been discovered.

The Rocky Mountain Range consists of limestones with quartz-
ites and shaly beds, dolomites and red sandstones. The latter
have been observed near the 49th parallel, and are supposed to be
Triassic in age. The limestones are, for the most part, Carbon-
iferous and Devonian, and no fossils have yet 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 Wahsatch, on the 40th parallel, given by Clarence
King. Volcanic material is still present in the Carboniferous rocks
on the 49th parallel.

The oldest land is that of the Golden Range, and the
Carboniferous deposits laid down east and west of this barrier
differ widely in character. The Carboniferous closed with a dis-
turbance which shut the sea out from a great area east of the
Gold Range, in which the red gypsiferous and saline beds of
the Jura-trias were formed. In the Peace River region, however,
marine Triassic beds are found on both 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 Cretaceous in British Columbia lay east
of the Coast Range, and the sea communicated by the Peace
River region with the Cretaceous Mediterranean of the great
plains.

No Eocene deposits have been found in the province. The
Mioceue of the interior plateau is probably homologous with
King's Pah-TJte lake of the 40th parallel Miocene. In the Pliocene
the country appears to have stood higher above the sea-level
than at present, and during this time the fiords of the coast were
probably worn out. — Proc. Geol. Soc. London, 1881.

2. Caribbean Miocene fossils. — A memoir, on Miocene fossils
of Sapote, Costa Rica, and a few from Gatun, on the Panama
Railroad, by the late W. M. Gabb, is published in Part IV of
vol. viii (2d Ser.) of the Journal of the Academy of Natural
Sciences. A number of the species are identical with Miocene
species of San Domingo.

3. Report of the State Geologist of New .Jersey for the year
1 880. — Professor George H. Cook, the State Geologist, devoted 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, including the facts as to the course
of the terminal moraine across the State, terraces along valleys,
and those as to other gravel and sand deposits, chiefly in South-
ern New Jersey, 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. One of the most remark-
able bowlder deposits in the southern extremity of the State is in
Cape May County, about Dennisville, especially between Dennis
Creek and Cumberland County. The bowlders have worn but
not rounded edges, and have not been observed to have glacial,
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 60 feet above their present level.

At Paterson a well has been sunk 2100 feet in the Red Sand-
stone (Triassic), proving thus 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, it containing about half as much common
salt as the water of the ocean, and more of chlorides of potassium,
calcium and magnesium. The total amount of solid matter per
gallon was 929*46 grains.

4. Geological Survey of Pennsylvania. — The legislature of
Pennsylvania has passed, and the Governor has approved, a bill
appropriating $125,000 to the State Geological Survey under
the direction of Professor J. P. Lesley. This insures the
completion of this great work in 1883, ten years from its com-
mencement, the whole expense having been $445,000, besides the
printing.

Ihe Geology of the Oil Regions of Warren, Venango, Clarion
and Butler Counties ; by John F. Carll, Report I IT 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
the oil and of the associated beds; or of the topography, drain-
age, and drift phenomena of the districts. In addition, it gives
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 and Geology of
Indiana for 1880. — Jn Indiana, the duties of State Geologist were,
in 1879, transferred to the Bureau of Statistics and Geology, of
which Professor John Collett, an excellent 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 and chemistry. Professor Collett has pub-
lished two annual reports, the last of which contains about fifty
pages on geology with plates of fossils. j. m.

6. Illustrations of the Earth's Surface: Glaciers ; by N. S.
Shaleb, Professor of Palaeontology, and Wm. M. Davis, Instruc-

Geology and Natural History, 79

tor in Geology, in Harvard University ; 196 pp., large 4to, with
25 plates. Boston, 1881. (James R. Osgood & Co.) — The plan of
the series of which this volume is the first is to present illustra-
tions of prominent subjects in geology — Glaciers, Mountains,
Volcanoes, Earthquakes, etc., as far as possible from photographs,
and accompanying text giving "a connected idea of the more
essential facts and theories that belong to each subject." The vol-
ume which has been issued, on Glaciers, is exceedingly well adapted
for its purpose. Its illustrations represent some of the most char-
acteristic of glaciers, with a degree of perfection scarcely exceeded
by the photograph, and on a scale of magnitude, owing to the large
4to size, that exhibits all details in perfection. Among them are
the Glacier des Bossons, de Talef re from the Jardin, the Aletsch in
several views, du Geant, and others, in the Alps, with some from
the Himalaya, Norway, etc. Besides these, several plates are
devoted to other Glacial phenomena, and some to those of the
Glacial era, especially the American. The subjects are happily
chosen for instructiveness, and the beauty of the plates is remark-
able. The text gives an excellent general review of the subject
of glaciers modern and ancient, with many important descriptive
details. It discusses Croll's theory of the origin of glacial cold,
with criticisms, and also other opinions on the subject ; treats of
the movement of glaciers ; of glacier deposits ; of soils from
glaciers ; of the blue and yellow clays — attributing the latter to
oxidation since deposition, as done by Van den Broeck in the work
mentioned beyond. The volume is a very valuable one for both
instructor and student.

7. The Trilobite: New and Old Evidence Relating to its Organ-
ization; by C. D. Walcott. Bull. Comp. Zool., vol. viii, No. 10.
— Mr. Walcott here presents the results of his remarkable dissec-
tions of Trilobites, with full illustrations on six plates. The
species examined were Cer auras pleitrexanthemus, Calymene
senaria, and Asaphus platycephalus. The results show, beyond
question, the existence of a series of jointed organs about the
mouth, and appear to indicate a continued series down the thorax
and into the pygidium, besides exhibiting remains of ambiguous
organs, looking as if spiral, and supposed by the author to be
branchial in relations. A "restoration" of Calymene senaria is
given on plate vi. The series of legs in this restoration looks
very doubtful, for, if so distinct in the animal, it seems to be
incomprehensible that such dissections should have been needed
for their discovery. A series of distinct ambulatory legs on a
large Trilobite should have been large and stout, and could
hardly have escaped preservation in the form of large and stout
limbs. It may be that the supposed joints of the legs of the
orax and posterior extremity, which have the appearance of
stving been thin or membranous, are merely subdivided and
Slackened portions of the outer ventral shell, which served as
^•"ttachments for thin membranous articulated appendages such
fi have hitherto been attributed to Trilobites. j. d. d.

80 Scientific Intelligence.

8. Geological Survey of Alabama: Report of progress for
1879 and 1880 ; by Eugene A. Smith, Ph.D., State Geologist;
158 pp., 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.

9. The Felsites and their associated rocks north of Boston; by
J. S. Diller. 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, Maiden, 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-
tive : granite, f elsyte, dioryte, and diabase and melaphyre.

10. Met noire sur lea Ph'enorn&nes oV Alteration des Depots super-
ficiels par V infiltration des eaux Meteoriques, eta dies dans kurs

rapports avec la Geologie stratigraphique, par Ernest Van den
Brosck, Conservateur au Musee Royale d'Histoire Naturelle, At-
tache au service de la Carte Geologique. 180 pp. 4to, with a
folded plate. Bruxelles, 1881. From vol. xliv of M6m. Couron-
nes et Mem. des Sav. Etr. of the Brussels Academy. — The facts
and conclusions in this important memoir sweep awav much that
is erroneous in Quaternary stratigraphical geology. T*he principle
appealed to is one well understood — that iron-oxidation and other
metamorphic changes are carried downward into deposits, consoli-
dated or not, by infiltrating waters ; but the extent of the changes
thus occasioned has not been so well appreciated. On this point
the observations of the author throw much light. The diluvial
deposits of many parts of western Europe have been described as
consisting of " diluvium gris " below and " diluvium rouge " above;
and the distinction has seemed to be of special importance by many
recent writers. The author shows, and illustrates his facts by many
sections, that the red beds are the gray beds turned red by oxida-
tion through infiltering waters. His sections represent downward
prolongations of the red into the gray, and layers of gravel of the
gray beds continuously through the red without interruption or
disturbance. In other cases gray beds are overlaid by yellow
beds or gray clays by yellow clay deposits ; and as before, the
upper yellow bed is not a distinct bed, but a result of the super-
ficial alteration of the gray through infiltrating waters producing
oxidation. The large plate contains a number of colored sections
of Quaternary deposits, fully sustaining his conclusions.

11. On the application of a solution of mercuric potassium- -
iodide in mineralogival and lithological investigations, by V—
Goli>k(!iimii>t. — The ingenious method for separating mechan —
ically the mineral constituents of a rock, proposed by M. Thoulet,^
has already been extensively employed by lithologists. Thiss
method is based upon the fact that a solution of mercuric iodides
and potassium iodide in water may be obtained having a very-^

Geology and Natural History, 81

high specific gravity ; and further that, by the addition of dis-
tilled water drop by drop, any required density, from the maxi-
mum (Thoulet) 2*77, down to 1, may be obtained. If now the
fine fragments of a rock be introduced into the solution, those whose
density is equal or less than that of the solution will float and all
others will sink. By carrying on the process in a suitable vessel
and by varying, as circumstances require, the density of the men-
struum, the separation of several different minerals may be accom-
plished. For the further discussion of the subject, as given by
M. Thoulet, reference must be made to his valuable memoir on
" Contributions a l'6tude des proprie'te's physiques et chimiques
des mineraux microscopiques ;" Paris, 1880 (also Bull. Soc. Min.
France, ii, 17, 1881). This method has been exhaustively studied
by Goldschmidt, and the results given in his memoir show how
much can be accomplished in this way that was impossible by
any of the earlier methods of mechanical separation ; at the same
time he calls attention to the conditions upon which success de-
pends and to the various opportunities of error. The maximum
density obtained by him was 3*196 but varying 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
of a large series of specimens of different kinds of feldspar and
concludes that the method gives a sure means of separating the
different species of the group when fresh and pure. In regard to
the best manner of separating the constituents of a rock the au-
thor gives many practical hints of value, and details the results
obtained by him in a number of typical cases. It has also been
proposed to use this solution of mercuric potassium iodide for
various optical purposes as that of determining the indices of
refraction by total reflection by the method of Kohlrausch.
Goldschmidt finds the maximum index of refraction to be 1*73
(for D) and he has investigated the variation in refractive index
for solutions of different strengths. — Jahrb. Min., 1881.

12. Deer horns impregnated with tin ore.— Mr. J. H. Collins
describes, in the Transactions of the Royal Geological Society of
Cornwall, deer-horns, now in the British Museum, that were
found in the tin-bearing gravel of the Carwon and Pentewan
Valleys, which are impregnated with tin-ore, and seem to have,
c<in some parts, the original horn structure almost entirely pre-
served or reproduced in oxide of tin" and even contain in places
visible crystals of this oxide. They are reported as having been
"Cormerly common and as having been sold as block tin to
"fche smelters. These specimens have not been analyzed ; but a
fragment, belonging to the Cornwall Geological Society, which
^^ppears to be part of the horn of a Cervus elaphus (the red
^3eer) afforded him on analysis 2*60 per cent, of stannic oxide,
^^nd 1*66 of iron sulphide; and, although the amount of these
introduced ingredients is small, they were found, on microscopic

Am. Jour. Sol— Third Series, Vol. XXII, No. 127.— July. 1881.

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 Coxinty, Virginia. — The rare species
microlite, hitherto known only in minute crystals from Chester-
field, Mass., Branchville, Ct., and Uto, Sweden,, has been recently
found by Prof. W. M. Fontaine in Amelia County, Va., and is
described by Prof. F. P. Dunnington. It occurs in isolated octa-
hedral crystals from ^ to £ inches in diameter and in larger crys-
talline masses, one of which weighed eight pounds. The physical
characters are: H.=6 or a little less; G.=5*656; luster glistening
resinous ; color, wax yellow to brown ; streak, pale ochreous yel-
low; sub-translucent; fracture conch oidal; very brittle. An analy-
sis gave : —

Taa06 Cb206 W08 SnOa CaO MgO BeO UaO, Y90,
68-43 7*74 0*30 105 1180 101 0'34 1*59 0*23

Cea08, DiaOs Ala08 Fe908 NaaO KaO P H90, deduct

v <-

0-17 013 0-29 286 0*29 285 1.17

O replaced by F
1-20 = 99*05

This shows the mineral to be essentially a calcium pyrotanta-
late. The formula deduced is— j ?^ ^V + CbOF,.

— Amer. Chem. Journal, iii, 130, May, 1881.

14. My a arenaria. — A paper in the American Naturalist for
May last, by R. E. C. Stearns, reports that this mollusk, the "long
clam " of eastern waters, has recently become the " leading clam "
in the markets of San Francisco and Oakland, although unknown
on the coast until the discovery of a few specimens on the eastern
side of Francisco bay in 1874. How introduced is yet an unan-
swered question.

15. Rhizopods, the food of some young Fishes. — Dr. Leidy
reports that the young of some of the suckers (CatostomicuB),
Hypentelium, Myxostema, etc., have been found by Mr. S. A.
Forbes, of Illinois, to have the intestines packed with tests of
Difflugia and Arcella, indicating that they feed on Khizopods.
In a slide containing material from the intestines of the young
Mullet (Myxostoma macrolepidotum) from Mackinaw Creek,
prepared by Mr. Forbes, Dr. Leidy distinguished Difflugia globu-
losa and D. acuminata ; and in another of the food of JEremyzon
succetta he found Difflugia globulosa, D. lobostoma, D. pyri-
formis, Arcella vulgaris, A. discoides, besides another peculiar
undescribed form. — JProc. Acad. Nat. Sci. JPhila., Jan. 4, 1881.

III. Astronomy.

1. On the Figures of the Planets. — The conclusions of Pro —
fessor Hennessy in regard to the form of the planet Mars have^
been given on p. 162 of the last volume of this Journal (Feb.,^
1881). In a recent paper in the Comptes Rendus (1881, p. 225) ^

Astronomy. 83

he gives the formulas deduced by him for the compression (e) of
a planet resulting from superficial abrasion, and shows that this
would be sensibly less than that resulting from the hypothesis of
primitive fluidity. The application of the formulas to the planets
whose times of rotation and mean density are most similar to the
earth give the following results : —

For the planet Mercury, if we admit 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 = — ; and if the planet were homogeneous,

_ 1

325

With the same law of density as in the earth, on the fluid theory,

__ 1

6-JT3;

and on the theory of abrasion,

__ 1

586

These three results show that for Mercury no sensible compres-
sion is likely to be observed.

For Venus, if we adopt the values of the mass M, time of rota-
tion T, and diameter a, generally admitted, namely

M = 412l60' T = 23h2l-22% a='954,

I find for the compression, on the hypothesis of fluidity and a law
of density like that for the earth,

_ 1

6 -247'

snd by the hypothesis of abrasion at surface,

__ 1

351

The first of these values approaches closely to the compression

Tecently observed by Colonel Tennaut — namelv, e = -— . So

j j - ' 260

far, therefore, the figure of Venus is more consistent with the
theory of fluidity than with the theory of superficial abrasion.

Since I communicated my note on Mars to the. Academy, I
have become acquainted with the new determination of the planet's
mass obtained from the motions of its satellites. The astronomers
of the Washington Observatory have devoted especial attention
to the satellites of this planet. Professor Asaph Hall has pub-
lished results* which lead to the conclusion that the mass of Mars

is probably about 3^L^.

With this value, and the values of other elements remaining
* Washington Astronomical Observations, xxii, Appendix.

8-i Astronomy.

the same as in my previous note, Q becomes -— — or — - nearly.

J r ' ^ 203*74 204 J

1 1

The compression on the fluid theory becomes or — . On

the theory of abrasion the compression is — - . The first is much

nearer to the observed compression — than the last.

It thus appears that, for the earth and the planets nearest to it,
and whose mean density and general appearance make it probable
that their materials resemble those of the earth in physical and
mechanical properties, the compressions deduced from the theory
of fluidity agree much better with observation than the compres-
sions deduced from the theory of superficial abrasion. — Phil. Mag.,
April, 1881.

2. Observations of the Transit of Venus, Dec. 8-9, 1874.
Part I. Washington : Government Printing Office. 1880. Edi-
ted by Simon Newcomb. — 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-
graphs with their reduction and discussion. The present part
gives the general account of the operations and the reduction
and results of the observations, and logically might have been the
last instead of the first part.

The most important chapters are the third aud fourth. The
discussion of photographic instruments and measurements, and
the formation of the observation equations fill the third chapter.
There were over 200 photographs which could be measured, fur-
nishing over 400 observation equations for determining the most
probable corrections to the tabular place of the planet and the
assumed solar parallax.

The discussion of the errors and discrepancies among the pho-
tographic results, and the determination of a value of the solar
parallax are not given, as the Astronomische Gesellschaft has
discouraged the publication of separate results for the solar par-
allax until the whole of the observations of all parties can be com-
bined in a single discussion. The remark is made, however, that
the probable error of the photographic measurements far exceeds
what was originally estimated.

The fourth chapter gives 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 lessons which these results furnish with reference to the
observations of the transit in 1882 are not developed, but it seems
probable that the photographic methods must be improved, or else
not made our principal reliance in the coming transit, h. a. n.

3. Observations of Double Stars made at the U. S. Naval
Observatory ; by Asaph Hall. — Professor Hall has given in

Miscellaneous Intelligence. 86

this memoir the results of his observations on double stars with
the twenty-six 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 with Mr. Struve and Baron Dembowski, for the pur-
pose of eliminating constant errors of position 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 double star is worth scores of those of moderate or doubtful
value, we appreciate more highly the value of such a series of
observations by such an observer. h. a. n.

IV. Miscellaneous Scientific Intelligence.

1. Historical Sketch of the Boston Society of Natural History,
with a notice of the TAnncean Society which preceded it; by
Thomas T. Bouvb. 250 pp. 4to, with several portraits. From
the Anniversary Memoirs of the Boston Society of Natural
History, published in celebration of the Fiftieth Anniversary of
the Society's foundation. — This volume comprises an important
part of the history of American science. The Linnaean Society,
which was the predecessor of the Natural History Society, was
begun in 1814, at first under the name of The New England
Society of Natural History, but a month later, that of the Lin-
nsean Society of New England, and in 1823 its last meeting was
held. When the Boston Society of Natural History commenced,
in 1830, it acquired possession of what remained of the collec-
tions of the LinnaBan Society, but " nothing of any considerable
value was obtained." The society was without endowment, and
the income for the first year from the fees of members and a
course of lectures, after deducting the expenses of the lectures,
was but little over five hundred dollars. Through the liberality
of its friends, it now has a fund of more than $150,000, a build-
ing that cost as much as this, a large library, extensive collec-
tions, and many volumes of its own published Memoirs and
Proceedings. Considering the expenses of publication, of the
care of specimens, the great importance of extending the collec-
tions, ana the required outlays for curators, librarian, and other
urgent needs, the amount is still small; and yet that it is so much
is an honor to the generous citizens of Boston, who are sure to
keep making it larger. Mr. Bouv6, in his excellent history of the
society, gives the details of the society's progress and a general
account of the work it has accomplished. The volume contains,
also, brief, life-like sketches of the members that have died,
among whom are a number that will be long remembered in
science — Dr. Benjamin D. Greene, Amos Binney, Dr. Burnett,
Dr. Warren, Dr. Harris, Dr. Gould, Charles Pickering, Agassiz,

86 Miscellaneous Intelligence.

Wyman. Dr. Wyman was president for fourteen years (fronzzM
1856 to 1870), and, like Agassiz, was a man to be ever kept ir*_
mind for his excellencies by future generations of laborers in
science. The Boston Society 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 Association for the Advancement of Science
opens at Cincinnati on the 17th of August. Professor George J.
Brush, of New Haven, Conn., is President of the meeting ; Pro-
fessor A. M. Mayer of Hoboken, N. J., Vice-President of Section
A.; F. W. Putnam, of Cambridge, Mass., Permanent. Secretary,
and C. V. Riley, of Washington, D. C, General Secretary. The
Chairman of the Subsection of Chemistry is W. R. Nichols, of
Boston, Mass.; of Microscopy, A. B. Hervey, of Taunton, Mass.;
of Anthropology, Garrick Mallery, of Washington, D. C; of
Entomology, J. G. Morris, of Baltimore, Md. — The headquarters
of the Association in the city will be at Music Hall ; there will
be found the offices of the Permanent Secretary and Local Com-
mittee, as well as the rooms for the sessions, and the book for
registering the names of members on their arrival.

3. On the so-called Cosmical Dust. — Dr. Lasaulx has investi-
gated the subject of the mineral dust which at different times has
been collected at various points on the earth's surface and for
which a cosmical origin has been assumed. The memoir by Nor-
denskiold on this subject, noticed in this Journal, ix, 145, 1875, is
reviewed and some of the conclusions there reached questioned.
A portion of the original material from the interior of Greenland,
named by Nordenskiold cryoconite, was examined microscopically
and was found to be not even approximately homogeneous. On
the contrary, the dust was made up of particles of quartz, mica,
orthoclase and triclinic feldspars, magnetite, garnet, epidote and
hornblende, and, with these, brown or brownish-green particles of
organic nature probably microscopic algae. Dr. Lasaulx concludes,
from the absence of augite and chrysolite, that the dust could not
have come from a volcano, but that it was derived from the
gneissoid rocks on the coast of Greenland ; that there is no reason
to think of a cosmical origin for it, and the presence of quartz and
mica declare against this idea. The dust of Catania, Sicily, which
was described by Silvestri and has been regarded as cosmical,
Lasaulx has also investigated. His conclusion is that all the
materials present in it could have been, and in all probability were,
derived from Mt. Etna. A study of the residue obtained by the
melting of a large quantity of snow collected by the author in
the neighborhood of Kiel revealed no minerals for which any-
thing but a terrestrial source need be predicated. In conclusion,
Lasaulx decides that the atmospheric dust is in general to be
regarded as terrestrial detritus, and that before a non-terrestrial
origin can be considered proved in any case, a much more critical
microscopic examination must be made than has been customary
in the past. •

THE

AMERICAN JOURNAL OF SCIENCE.

[THIRD SERIES.]

• ♦»•

Art. XV. — Upon a modification of Wheatslone's Microphone and
its applicability to Radiophonic Researches; by Alexander
Graham Bell.

[A paper read before the Philosophical Society 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, f This explanation has recently been called
in question by Mr. Preece,J 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 in the
air itself by sudden expansion due to heat communicated from
the diaphragm — every increase of heat giving rise to a fresh
pulse of air. Mr. Preece was led to discard the theoretical
explanation of Lord Raleigh on account of the failure of experi-
ments undertaken to test the theory.

* American Association for the Advancement of Science, Aug. 27, 1880.
f Nature, vol. xxiii, p. 274. % Roy. Soc, March 10, 1881.

Am. Jour. Sci.— Third Series, Vol. XXII, No. 138.— August, 1881.

88 A. 0. Bell — Applicability of a modification of

He was thus forced — 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-
ble sounds result from the expansion and contraction of the
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
it might easily happen that both the
supports (A, B,) of the microphone might
touch portions of the diaphragm which
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
to-night the apparatus by means of
A, B, carbon supports; which this point has been 'investigated.

c, diaphragm. (See fig. 2.)

The instrument is a modification of the form of microphone
devised in 1827 by the late Sir Charles Whealstone, 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 rested
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). The 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 of
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.

Wheatsione's Microphone to Radiophonic researches. 89

&BBS&

■Vso^Mss.Trq

then explored with the point of the microphone, and sounds
were obtained in all parts of the illuminated area and in the
corresponding area on the other side of the diaphragm. Out-
side of this area on both sides of the diaphragm the sounds
became weaker and weaker, until at a certain distance from the
center they could no longer be perceived.

At the points where one would naturally place the supports
of a Hughes microphone (see fig. 1) no sound was observed.
We were also unable to
detect any audible effects
when the point of the
microphone was rested
against the support to
whi6h the diaphragm was
attached. The negative
results obtained in Eu-
rope by Mr. Preece may
therefore be reconciled
with the positive results ^
obtained in America by
Mr. Tainter and myself.
A still more curious de-
monstration of localiza-
tion of vibration occurred
in the case of a large me-
tallic mass. An inter-
mittent beam of sunlight
was focussed upon a brass
weight (1 kilogram), and

the surface of the weight A, stiff wire; B, diaphragm; C, hearing tube;
was then explored with D> perforated handle. Figure reduced oue-half.

the microphone shown in fig. 2. A feeble but distinct sound
was heard upon touching the surface" within the illumin-
ated area and for a short distance outside, but not in other
parts.

In this experiment, as in the case of the thin diaphragm, abso-
lute contact between the point of the microphone and the sur-
face explored was necessary in order to obtain audible effects.
Now I do not mean to deny that sound waves may be origin-
ated in the manner 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 0. N. Rood — Obtaining and measuring very high Vacua

Art. XVL — On a method of obtaining and measuring very
high Vacua with a modified form of Sprengel-pump ; by
Ogden N. Rood, 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
11 00*0 ooo> while with my arrangement vacuua of 100 0j>0 000
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
years 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 of
utilizing them. Since then I have pushed the matter still far-
ther, and have succeeded in obtaining with my apparatus
vacuua as high as 350 0ft0 000, 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 of
experiments, certain in action and 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.

Reservoir.1— An ordinary inverted bell-glass with a diameter
of 100mm and a total.height of 205mm forms the reservoir ; its
mouth is closed by a well-fitting cork through which passes the
glass tube that forms one termination of the pump. The cork
around tube and up to the edge of the former is painted
with a flexible cement. The tube projects AO""11 into the mer-
cury and passes 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 CR, 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 and answers admirably. The pres-
sure of the cylinder on the end of the tube is regulated by the
lever S, figure 1 ; this is attached to a circular board which

with a modified form of Sprengel-pump.

again is firmly fastened over the open end of the bell-glass. It
will be noticed that on turning the milled head S, the motion
of the steel cylinder is not directly vertical, but that it tends to
describe a circle with c 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 a a, figure 2. The
weight of the cylinder and mercury is supported by a shelf, S,
figure 2, on which rests the cork of the cylinder; in this way
all danger of a very disagreeable accident is avoided.

533

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 27mm. 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
the proper level of the mercury in the bulb passes through the
point o, where the drops of mercury break off. The length of
the tube EC should be 150mm, that of the tube- ED 45mm ; the
bore of this tube is about the same as that of the fall-tube.

92 0. 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 l^S""11 ; its length above the bends (U, figure
2) is 310mm; below the bends the length is 815mm. 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 25mm below the bends when the pump is in
action. This is easily regulated by an adjustable shelf, which
is also employed to fill the bends with mercury when a meas-
urement is taken or when the pump is at rest. On the shelf
is a tube, 160^ high and 20mm in diameter, into which the end
of the fall-tube dips ; its side has a circular perforation into
which fits a small cork with a little tube bent at right angles.
With the hard end of a file and a few drops of turpentine the
perforation can be easily made and shaped in a few minutes.
By revolving the little bent tube througn 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 l*85mm, as ascertained by a
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 is
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 ; I
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 340mm high, 58mm in diameter, which can be raised
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 of
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 lOO11"11.

All 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. ex, 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 by a fine catbetometer 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 200mm, 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
lens 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-
bly 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 paste-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 reenter 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-
liver bubbles of air ; it and the attached tube are now to be
heated with a moving Bunsen-burner, when it will be found
to furnish for 15 or 20 minutes a large quantity of bubbles
mainly of vapor of water. After their production ceases the
pump is righted and the exhaustion carried farther. In spite
of a couple of careful experiments with the cathetometer I
have not succeeded in measuring the vacuum in the vacuum-
bulb, but judge from indications, that is about as high as that
obtained in an ordinary Geissler pump. Meanwhile the vari-
ous parts of the pump can be heated with a moving Bunsen-
burner to detach air and moisture, the cement being protected
by wet lamp-wicking. In one experiment I measured the
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 t 00ft 000 of the air originally present. I
have also noticed that a still larger amount of air is detached
by electric discharges. This coincides with an observation of
E. 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 the 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-jnimp. 95

bubbles and is condensed. Without this precaution I have found
it impossible to obtain a vacuum higher than 2 5 0 0\ 0 0 0 ; in
point of fact the bends should always be heated when a high
exhaustion is undertaken even if the pump has been standing
well exhausted for a week ; the heat should of course never be
applied at a late stage of the exhaustion. Conversely, I have
often by the aid of heat completely and quickly removed quite
large quantities of the vapor of water that had been purposely
introduced. The exhaustion of the vacuum-bulb is of course
somewhat injured by the act of using the pump and also by
standing for several days, so that it has been usual with me
before undertaking a high exhaustion to incline the pump and
reexhaust 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 and then the leakage remains quite
constant for months together.

Measurement of the vacuum. — 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-
cus," 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 mercury 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 go oo*o ooo an^ to pressures of five millimeters and
under. It is advantageous in making measurements to employ
large pressures and small volumes ; the correct working of the
gauge can from time to time be tested by varying the relations

96 0. N. Rood — Obtaining and measuring very high Vacua

of these to each other. This 1 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
volume of the " meniscus " was correct, etc. 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 ;

c= a factor which multiplied by n converts it into cubic

millimeters ;
8=cubic contents of the meniscus ;
d= difference of level between A and H, fig. 4;

= the pressure the air is under;
N=the cubic contents of the guage in millimeters;
x=& fraction expressing the degree of exhaustion obtained :
then

x = 77760

nc— S

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.

Gauge correction. — It is necessary to apply to the results thus
obtained a correction which becomes very important when
high vacua are measured. It was found in an early stage of
the experiments that the mercury in the act of entering the
highly exhausted gauge, gave out invariably a certain amount
of air which of course was measured along with the residuum
that properly belonged there; hence to obtain the true vacuum
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 followed
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 repeated
until they amount in all to six ; finally the volume and pressure

with a modified form of Sprengel-pump. 97

are a second time measured. Assuming the pressure to remain
constant, or that the volumes are reduced to the same pressure,

v=the original volume ;
</=the iinal volume ;

V'= volume of air introduced by the iirst entry of the mercury;
V= corrected volume; then

V= v - -

V — V

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 of

Dec. 2 1st.

27 308 805

Dpp, 29th

38 806 688

-Tan 1 £it.h

78 125 000

Jan. 23d.

83 333 333

1
128834 063"

..Feb. 1st.

1
226 757 400"""

. . . Feb. 9th.

Feb. 19th.

232 828 800""

Marp.h 7th

388 200 000"""

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 0. A'. Rootl — Obtainiwj and measuring very high Vacua

increase sensibly, when the exhausted pump and gauge are
allowed to stand unused for twenty days.

Rale of the pumps 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 j>ossible to calculate the
highest vacuum attainable with the instrument. Examples
nrc .iriven in the tables below : the total capacity was about
100,000 cubic mm.

Time. Kxhaustiou. Ratio.

78 511} j

10 minutes >■ 1 :

I \ 3 53

270 98U )

10 minutes > 1:

1 ) 6"10

I 687 140 . j

10 minutes > 1:

4-15

7 002 000

Upon another occasion the following rates and exhaustions
were obtained :

Time.

Exhaustion.
1

lo minutes
10 minutes

7 812 500

1
24 875 620

Rate.

„.!:-!

3*18
1

2-69

67 024 090 j x
10 minutes > 1:

1 J l^

81 760 810 i j

10 minutes r 1: — — -

1 ) I'M

136 986 300 ) 1

1 o minutes > 1 : — - —

1 1*23

170 648 000

Tl'io 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 becomes 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

experiment. mm., press. 760mm.

18£ hours -000853

27 hours -001565

26| hours -00079 1

20 hours _ -000842

19 hours -000951

19 hours -001857

7 days -003700

7 days -001574

Average -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

experiment. mm., press. 760in,n.

18 hours •_. -0002299

7 days -0004093

7 days _ -0003464

Average -0003285

This renders it very probable that the remaining three-quar-
ters are due to air given off from the mercury at B, fig. 4, from
that in the bends and at the entrance of the fall-tube o, i\g. 3.

Farther 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.

The gauge, when arranged for measurement of gauge-leak-
age, really constitutes a barometer, and a calculation shows
that the leakage would amount to 2*877 cubic millimeters per
year press. 760mm. If this air were contained in a cylinder
90mm long and 15mm in diameter it would exert a pressure of
•14mm. To this I may add that in one experiment I allowed
the gauge for seven days to remain completely filled with mer-
cury and then measured the leakage into it. This was such as
would in a year amount to -488 cubic millimeters press. 760mra,
and in a cylinder of the above dimensions would exert a pres-
sure of -0233mm.

100 0. N. Rood — Obtaining and measuring very high Vacua

Reliability of results ; highest vacuum.

The following are samples of the results obtained. In one
case sixteen readings were taken in groups of four with the
following result :

Exhaustion.
1

Mean

74 219 139

78 533 454

79 017 272

68 503 182

74 853 449

Calculating the probable error of the mean with reference to
the above four results it is found to be 2*28 per cent of the
quantity involved.

A higher vacuum measured in the same way gave the fol

lowing results:

146 198 800

175 131 300

1
204 081 600

201 207 200
The mean is -170411 qqa* with a probable error of 542 per

cent of the quantity involved. I give now an extreme case;
only five single readings were taken ; these corresponded to the
following exhaustions :

379 219 500

371 057 265
1

250 941 040
1

424 088 232

691 082 540

wich,a modified^fdrm^qf $pvengel-pnmpt - l '* ,' * « J01 ;

The mean value is 3S1 1^0 000, with a probable error of
10*36 per cent of the quantity involved. Upon other
occasions I have obtained exhaustions of 3?3 1|4 000 and
388 200 ooo* Of course in these cases a gauge-correction was
applied ; the highest vacuum that I have ever obtained irre-
spective of a gauge-correction was 190 8|2 lg0. In these
cases and in general, potash was employed as the drying ma-
terial ; I have found it practical, however, to attain vacua as .
high as go oo*o ooo *n tne tota^ absence of all such substances.
The vapor of water which collects in bends must be removed
from time to time with a Bunsen- burner while the pump is in
action.

It 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-
limeters at press. 760mm. Let us assume that the leakage when
the pump is in action is four times as great as when at rest ;
then in each ten minutes '000844 cubic millimeters press.
70Qmm wouid enter; this corresponds in the pump used by me
to an exhaustion of 184 0ft0 000 ; 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 248 0ft0 000.
In the same way it may be shown that if six minutes are re-
quired for the removal of half the air the highest vacuum
would be 418 0ft0 0ff5 nearly, and rates even higher than this
have been observed in my experiments. An arrangement of
the vacuum-bulb whereby the entering drops of mercury
would be exposed to the vacuum in an isolated condition for a
somewhat longer time would doubtless enable the experi-
menter to obtain considerably higher vacua than those above
given.

Exhaustions obtained with a plain Sprengel-pump. — I made a
series of experiments with a plain Sprengel-pump without
stopcocks, 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 cubic

experiment. mm. at press. 760mm.

22 hours -04563

2 days -04520

2 days -09210

4 days -06428

Mean -0618

Using the same reasoning as above we obtain the following
table :

* * m* • • •••••• • •• k » I «■ »»**••

• ••••• ' • • • • • •.*»/ ..*■. •-«■ «. %*

V W/°k & fiMfc.Obfo&Vfo *:afld Wjpfrfihg y&'&high Vacua, etc.

Time necessary for removal Greatest attainable

of ^ the air. exhaustion.

10 minutes

5 000 000

7*5 minutes

7 000 000

6*6 minutes

12 000 000

In point of fact the highest exhaustion I ever obtained with
this pump was t-vtv-ttt > fr°m which I infer that the leakage
during action is considerably greater than four times that of
the pump at rest. The general run of the experiments tends
to show that the leakage of a plain Sprengel-pump, without
stopcocks or grease, is, when in action, about 8U times as great
as in the form used by me.

Note on annealing glass tubes. — It is quite necessary to anneal
all those parts of the pump that are to be exposed to heat,
otherwise they soon crack. I found by enclosing the glass in
heavy iron tubes and exposing it for five hours to a tempera-
ture somewhat above that of melting zinc, and then allowing
an hour or two for the cooling process, that the strong polari-
zation figure which it displays in a polariscope was completely
removed, and hence the glass annealed. A common gas-com-
bustion furnace was used, the bends, etc., being suitably en-
closed in heavv metal and heated over a common ten-fold Bun-
sen-burner. Thus far no accident has happened to the annealed
glass, even when cold drops of mercury struck in rapid suc-
cession on portions heated considerably above 100° C.

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
kind.

New York, June 10, 1881

J. D. Dana — Origin of the Bocks of the Cortlandt Series. 103

Art. XIX. — Geological Relations of the Limestone Belts of
Westchestw County, New York; by James D. Dana.

Origin of the Rocks of the "Cortlandt Series."

In the account of the massive Cortlandt rocks* I have
shown that, although Archaean-like in the presence of the hy-
persthene-rock, noryte, in the abundance of hornblende and
augite, and the occurrence of corundum-bearing magnetite beds,
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
abrupt interpolation among the schists and limestones of the
region.

That the lithological facts may be in mind preparatory to
the following discussion I here re-mention the prominent kinds
of rocks.

1. Sodo>granite : granite-like, consisting chiefly of oligoclase
and biotite, with little quartz, and often containing some horn-
blende ; varying from coarse to tine in grain, and very light-col-
ored to black — the black very micaceous and fine-grained.

2. Dioryte, Quartz-dioryte : chiefly oligoclase and hornblende,
with more or less biotite, and a little quartz ; varying from very
coarse and granite-like to fine-grained.

3. Noryte : chiefly the feldspar, andesite — or, more probably,
its equivalent, 1 of labradorite and 2 of obligoclase — and hyper-
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 exceeding a sixth of an inch
in length, and never in folia.

4. Augite-noryte : like the noryte in aspect and constitution,
but containing augite in place of the hypersthene.

5. Hornblendyte : coarsely crystalline; chiefly black horn-
blende in small or large cleavable individuals.

6. Pyroxenyte : rather coarsely crystalline ; chiefly augite, but
sometimes a grayish-green pyroxene.

7 to 9. Chrysolitic hornblendyte, chrysolitic pyroxenyte, with
some chrysolitic noryte.

* This Journal, lor September last, III, xx, 104.

Am. Jour. Sci.— Third Sbribs, Vol. XXII, No. 128.— August, 1881.

104 J. D. Dana — Origin of the Bocks of the Cortiandt Series.

Other constituents of these rocks are frequently apatite (which
is often in unusual proportions), and more or less magnetite, pyr-
rbotite 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.

To 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.

8i0,

1. 66-28

2. 55-40

£10,
16-31
16-44

FeO,
069
085

FeO
7-57
7-51

MnO
040
039

MgO
5-05
5-05

CaO
752
7 49

Na,0
410
403

K,0
205
2-00

HaO

0 58 =99-55
[058] =99-73

Mean 55*34

16-37

0-77

7-54

040

5 05

7-51

406

2-03

0-58 =99-65

A trace of C09 also was obtained.

To the eye it appeared to contain about as much hypersthene
as augite, the crystals of the former being distinguished by a
brighter and somewhat bronze-like luster on a cleavage surface,
and a less black color ; and this proportion was confirmed, as far as
could be done, by a microscopic examination of a thin slice.
There was present also a little black mica, and some magnetite.
The results of the analysis may correspond, if 1*50 of the potash
replaces part of the soda, to about 61 per cent of andesite, 33 of
bisilicates, 5 of biotite and 1 of magnetite. But part of the pot-
ash may be present in orthoclase, and the andesite be, as above
recognized, a mixture of labradorite and oligoclase. The analysis
appears to show that in constitution the rock approaches closely
the dioryte of the region, but with this important difference, that
hypersthene and augite are present in place of hornblende and
the feldspar portion is more largely basic. The relation to the
noryte is much nearer, for one rock graduates into the other; and
the hypersthene, which is the characteristic mineral of the former,
has the same cleavage angle as augite, and the same constituents,
magnesia and iron protoxide, the augite affording besides only
lime. Hence the name augite-noryte for the rock is appropriate.
It has the mineral constitution of the so-called augite-andesyte,
and also of a part of what has been included by some writers under
the name melaphyiv.

The ovidonco already presented with regard to the Cort-
luiult rocks sustains the conclusion, as I believe, that to a
largo extent at least thoy are of metamorphic origin; but that
in the motamorphio process the original beds were rendered
(through tho heated moisture concerned in the metamorpbism),
more or loss 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 rooks having all the characteristics of eruptive rocks.

J. D. Dana — Origin of the Bocks of the Cortlandt Series. 105

But if u to a large extent " metamorphic, that is, altered sed-
imentary beds, Why were there, in that narrow corner of
Westchester County, covering but twenty-five square miles,
beds so unlike ordinary sediments in consisting of the mate-
rials of soda-lime feldspars, hornblende, pyroxene, and chryso-
lite, when, close around and throughout the county to its east-
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 Archaean Highlands. This relation to the posi-
tion of the Archaean and the river channel is shown on the
following map (p. 106). Upon it, .the Archaean 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 Archaean, south and southeast of
Peekskill on the east of the Hudson, and on Stony Point (ST)
on the west side of this river. Near Peekskill the Cortlandt
area is separated from the Archaean 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 Archaean, a contin-
uation of the same rocks (the limestone area on the map being,
as elsewhere, horizontally lined, and that of the slates, which are
partly quartzyte, distinguished by a vertical lining with white
and dotted bands). The portion of the map north of the Ar-
chaean and occupying valleys within its area, has been already
explained as Lower Silurian ; (1) limestone, (2) slates or schists
(vertically lined), and (3) 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

The larger map of western Cortlandt from Peekskill to Cru-
ger's (comprising the Verplanck peninsula) and also Stony
Point is reproduced on the following page, that the positions
of the several localities and of the limestone belts may be

106V D. Dam— Origin of the Rocksjofihe Oorthndt Series,

more distinctly before the reader, and especially the relations
.of Stony Point to Montrose Point and other places on the east .
side of the Hudson.

The eastern outline of the Archfean makes a large angle at
the crossing of the Hudson (the course on the west being north-
east, and that on the east, east- north east), so that the form was,
thus far at least, favorable for the existence there of a broad
bay in the Lower Silurian sea. The river-chaunel through the

Map of parta of New York and New Jer
nay: si, Stony Point, on the
the Hudson ; v, Verplanck ]

Highlands had not yet been made, as is indicated by the con-
tinuity of the Lower Silurian beds on the north of the High-
land area across from Fishkill, and that of the same on the
south across from Peekskill. The 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 aod the
material of the limestone formation. North of the Arcbiean,
in the Fishkill, Newburgh and Pougbkeepsie '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 Gor&tndt Series. 107

the like conformable association of quartzyte, slate and semi-
crystalline limestone in the Feekskill region, together with their

unconforraability lo the Archaean, and their relation to New
Jersey 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 Hie Rocks of the Cortlandt Series.

A freshwater stream must have emptied into this Cortlandt
bay near the present channel of the Hudson ; for thegeneral 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 Biver 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 Archaean detritus over the Cortlandt area. Nothing
could have come down the valleys called Canopus Hollow and 0
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 in a 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.

(3.) The 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.) The 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 gneissic
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
would not 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 Gortlandt Series. 109

layers retain such parallelism. 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 layers 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
deeply rusted.

It is almost an impossibility that a thin bed of limestone 80
feet long could by any means have got into the erupted rock ;
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, they 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 by
beds of mica schist or hornblendic sqhist. Such facts appear
to show that the most of the " veins" are beds, metamorphosed
into different mineral materials according to their varying con-
stitution ; and that the contact phenomena manifested are re-
sults of the original passage of one rock into the other along
the plane of junction and subsequent metamorphic conditions.

In order to appreciate rightly the bearing of the facts on
this question as to metamorphism, the mind should be disa-
bused of the common notion that a massive rock, whether feld-
spathic, hornblendic or augitic, is necessarily of eruptive origin.
As heat and moisture may convert siliceous sand-beds, under
pressure, into hard massive quartzyte without the intervention
of fusion, so also it may convert granitic sand-beds into a gran-
ite or granite-like rock, as has happened north of Peekskill.
Again, the same means, even when the heat is far below that
required for fusion, may destroy molecular cohesion, and, as
numerous examples show, may convert, by the recrystallization
attending metamorphism, well-bedded strata of hornblendic,
augitic or feldspathic material into a massive rock, often undis-
tinguishable even microscopically from an eruptive rock. One
example in proof is given in my paper in the June number of
this Journal (p. 428) ; and others in papers on the Helderberg
rocks 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.

The characteristics of the beds to be accounted for are : (1)
the predominance of the magnesian minerals, hornblende, au-
gite, hyper^thene, biotite, chrysolite; (2) the abundance of
soda-lime feldspars ; and (3) the small proportion of free
quartz.

The three supposable sources of such characteristics are —

(1) Detritus from the Archaean Highlands.

(2) Igneous eruptions, affording volcanic or igneous debris,
in addition to ejected liquid rock, and along with more or less
Archaean detritus.

(3) Detritus from the Highlands, supplemented by ingre-
dients from the ocean.

1. ARCaSAN DETRITUS.

The rocks of the Archaean region of the Highlands are
largely hornblendic — the gneiss being often a hornblendic
gneiss and varying, in many places, to syenyte-gneiss, true
syenyte, and hornblende schist ; and the mica, whether horn-
blende is also present or not, is mostly or wholly the black
kind, biotite, which, while containing nearly as much pot-
ash as muscovite, is characterized by a large percentage of
iron and magnesium. Occasionally augitic rocks are present,
especially in the vicinity of beds of iron ore. Augitic and
hornblendic rocks abound on Anthony's Nose, which is one of
the high summits of the Highlands, just to the north of Cort-
landt, and they occur less prominently near West Point.

Magnesian as well as ferriferous sediments might therefore
have come from such a source ; and the frequent occurrence of
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 in
the separating process of wave-action or water-movement, and
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 Highlands, 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 Arch»an of
the Adirondacks, labradorite rocks, closely like the noryte and

J. D. Dana-*- Origin of the Rocks of Hie Cortlandt Series. Ill

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 probable,
since a drift specimen has been found in central New Jersey,
according to Dr. T. Sterry Hunt, and it is not likely that it
came from the distant Adirondacks.

Further : chrysolite, although common in igneous rocks, is
also common as a metamorphic product, and occurs even in
chloritic and mica schist and other rocks, as should be ex-
pected from its composition and easyjproduction by heat.

Doubts with regard to Archaean detritus as the only, source
of these Cortlandt rocks come from the very 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
large an area of soda-lime feldspar rocks, when they are not
found in a similar way over any other part of Westchester
County, the material 01 whose rocks, the limestones excepted,
must have come from the Highlands ; the existence of no sim-
ilar group of rocks in the great central valley of the New Jer-
sey Highlands (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 eastern border of
the Archaean in New Jersey is under Triassic beds, so that
scarcely anything is known of the Lower Silurian strata directly
southwest of Stony Point.

2. Igneous ejections along with more or less Archjean detritus.

In favor of igneous ejections as a chief source, there are the
following facts.

The larger part of the rocks are much like igneous rocks.
They resemble them (1) in mineral constitution ; (2) in their
soda-lime feldspars; (3) in the abundance of hornblende or
augite ; and (4) in thejfeeble proportion of quartz. The noryte,
though containing hypersthene, offers no objection to the view.
The chrysolitic feature of the rocks of some parts of the region
is a frequent volcanic characteristic.

But 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
igneous rocks; (2) that no vents or^dikes have been found to
indicate the places of their ejection ; (3) that sometimes mix-
tures of two or three kinds occur — as hornblendyte, pyroxen-
yte and augite-noryte — which were not combinations made by
separate ejections but are merely irregularities of constitution in
a single large mass of rock ; and occasionally the noryte and

112 J. D. Dana — Origin of the Rocks of the Corllandt Series.

cbrysolitic hornblendyte are in united layers each only an inch
or two thick ; and (4) there are transitions into mica schists not
thus easily explained.

;bat the rocks are not truly

t aure that they have not

ted in depositions of vol-

or cinders (lapilli,

"volcanic ashes'"

submarine or sub-

I vents. For, in that case,

he kinds of material might

e same that constitutes erup-

rocks; (2) mixtures of the

meat kind observed might

been made ; and (3) the most

it transitions from cinder-

i beds to those of ordinary

sediments might result, even to the intercalation of a layer
of limestone or mica schist, or magnetic iron, or emery,
besides all. degrees of shading from one to the other; more-
over (4) the unique character and contracted limits of the area
might in this way be fully explained. Such beds of volcanic
debris, afterward undergoing metamorphism simultaneously
with the general metamorphism of Westchester County strata,
would be likely to come out under the various forms and feat-
ures presented by the rocks described ; and even if, iu 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 Gortlandt Series. 113

plastic and have been injected into fissures so as to produce
dike-like veins, and might retain internal marks of their former
mobility in broken crystals, if not in other evidences of
flowing.

As to the centers of eruption, it is to be noted that the occur-
rence of chrysolitic rocks on both sides of the Hudson — along
the shores of Stony Point on the west and of Montrose Point on
the east — with noryte adjoining, and next beyond, the soda-
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 chrysolitic rocks. The chrysolitic rocks thus occupy ap-
proximately the middle portion of the synclinal, f

The soda-granite is mostly of the coarsely crystalline, light-
colored 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 Mountain Institute, Haverstraw, N. Y., obligingly made at the request of
the writer.

f In my former account of the Point, I showed that the Tompkins Cove limestone
stratigraphically underlies the mica schist, it dipping under it, as at Cruger's;
and the more recent examination confirms this conclusion. It is therefore prob-
able that the stratum to the north of the Point bends around following the flex-
ure of the schist; and that.it lies beneath the area of Triassic conglomerate, and
thence extends eastward along the bed of the Hudson.

It is a fact of interest that at Cruger's this overlying schist is Jibrolitic, just
like the overlying gneiss adjoining the limestone of New York Island. The
fibrolitic gneiss of 123d street, on the corner of Lexington avenue, is but a few
yards from the limestone.

In the interior of the peninsula between the schist and the granite, but quite
near the junction with the chrysolitic rock, occurs a thick stratum of limestone
(see map, p. 112). It is about conformable to the schist on the j?ouih of it, but stops
off to the northward with a nearly vertical dip (70°-80° N.) and. a strike of N.
70° E. The limestone is situated somewhat like the small beds in the interior of
the Verplanck peninsula, and as near to the massive rock ; the latter was proved
in one case to be conformable to planes of bedding in the neighboring noryte ;
and in another case, to the mica schist ; but the relations of this Stony Point bed
to the massive rocks I could not determine. As in Verplanck it. is probably a dis-
tinct stratum from that of Tompkins Cove ; it is semi-crystalline like that, while
oth9r parts are coarsely granular, tremolitic and somewhat garnetiferous.

The Tompkins Cove limestone, on the shore just north of the limits of the
above map contains many veins of quartz, and assays made for the proprietor,
Mr. Edward A. Swain, have proved that the quartz is auriferous.

114 J. D. Dana — Origin of the Rocks of the Oorilandt Series.

southern entrance to the grounds a dike (or vein) two feet wide,
of the black micaceous variety, intersects the mica schist cutting
obliquely across its bedding.

The direct contact of the granite and chrysolitic rocks is no
where in sight But where the granite ends near the chrysolitic
rocks it stands in a nearly vertical wall, having approximately
the same strike and dip as the schists to the southeast. The
position of the chrysolitic rocks suggests an igneous origin.

With regard to the time of the ejections, supposing these a
fact, the evidence stands as follows :

The hornblendic and augitic materials occur in conformable
beds in the limestone of Verplanck point, looking like dikes
or veins because now nearly vertical, as has been explained ;
and hence this material must have been supplied when the
limestone was forming ; and the limestone is part of the same
stratum, as has been shown, with that of Canopus Hollow,
Tompkins Cove and Cruger's Station. Moreover, the dip of
the beds seem to indicate that these rocks overlie the lime-
stone of the region. Hence the eruptions were in progress
while the limestone was forming, and continued on for a
period after it

It may be objected to this view of an igneous source that
the chrysolitic pyroxenyte and hornblendyte are very unlike
ordinary igneous chrysolitic rocks, the chrysolite never being
in glassy grains ; that chrysolitic pyroxenyte, though a known
kind, is not in all cases igneous ; and that chrysolitic horn-
blendyte like that here met with (having hornblende cleav-
age faces measuring sometimes two inches each way) is
still less like an igneous product. So, also, soda-granite
is a very unusual form of eruptive rock, and likewise
dioryte with crystals of hornblende sometimes eight or
nine inches long, like that near Cruger's. But these diffi-
culties, and others like them, lose much of their force in view
of the fact that the beds may contain more or less ordinary
detritus, as well as volcanic debris, and especially the other
fact that they have undergone metamorphism since their depo-
sition, and in some cases have thereby suffered partial or com-
plete fusion.

Again, it may be urged in objection that we have no defi-
nite evidence as to the former existence of such a vent in the
channel of the Hudson, or of any other in the region. This
objection may hereafter be strengthened, or, on the other hand,
weakened, by finding that among the dikes of igneous rocks
which intersect the Archaean in various places, some, or none,
consist of rocks similar to those of Cortlandt

Professor Cook, in his Geological Eeport of 1868, at page
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
of 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 IX, in this Journal for last November) ; and
he speaks of it as constituting a dike a fourth of a mile wide
and several miles long, coming in between the Hudson Eiver
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.) Aech^an detritus, supplemented by Materials prom 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 (3) the soda, through the sodium
chloride or common salt.

The 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 argillaceous sand beds have been made
since the first Khizopods appeared 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, the 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.

Further, when the magnesian limestones thus made were
afterward rendered metamorphic, part of the magnesia and
lime (or magnesium and calcium) was in many cases made
into silicates, such as tremolite, white pyroxene, and other
species; or, when iron has also been present, into other related
silicates of light or dark green tints, as hornblende, actinolite,
green pyroxene; and also into other magnesian minerals
through other impurities of the limestone.

Thus the magnesia of the ocean's waters has beyond doubt

116 J. D. Dana — Origin of the Rocks of the Cortlandt Series.

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. The 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
penetrated through Carboniferous and Lower Silurian strata
into the Archaean, reached a depth of 3,843i feet u 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, 4i 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 Eeport 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 Archaean 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 : u the questions suggested by finding the
salt water must remain for the present unanswered, though the
fact that the rock-salt of Europe is found in rocks of the same
age as this raises the question whether it may not also be
found here."

Eocks containing salt in beds or brines have undoubtedly
undergone metamorphism, and under conditions as to superin-
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— 1814, 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 volcanic products ; and hence referring to it as a source of
the more stable bases with which these were combined is not
unreasonable.

In Savoy, as has long been known, the crystalline magne-
sian limestone or dolomite of the Trias contains the soda-feld-
spar, albite, in disseminated crystals. The magnesia of the
limestone must have come from evaporated sea-water as above
explained ; and the soda of the feldspar which, in the meta-
morphic process that crystallized the dolomite, went to make
albite may have had the same source.

Messrs. F. Fouqu6 and Michel L6vy have recently made*
crystallized oligoclase and labradorite by heating a mixture of
silica, alumina (each of these in the states obtained by precipi-
tation), sodium carbonate and calcium carbonate in the re-
quired proportions, and keeping it in prolonged fusion. They
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)
would in all probability yield the same result ; as is indicated
by the use of common salt in putting a glazing on porcelain
(while it is at a high heat) the chlorine escaping and yielding
the sodium to make a silicate, or the glaze. The possibility
of producing soda-lime feldspar in the metamorphism of a
saliierous 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 Fouque.

Crystalline rocks made largely of soda-lime feldspars, —
some of which are diorite, noryte, and the labradorite rocks
called gabbro — covering many large regions, are in some cases
unquestionably of metamorphic origin; and if detritus from pre-
existing rocks were not a sufficient source for the soda of the
feldspars and the magnesia of the hornblende or augite, and a
volcanic or igneous source is not indicated by surrounding
conditions, there must have been at hand some other large and
abundant source ; and the universal ocean is of just the kind
needed. Near New Haven, Connecticut, achloritic hydromica
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. Iravii, 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 " volcanic-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 likelv 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 have
come from the permeating brine water. This example may
illustrate the mode of origin of other metamorphic labradorite
and oligoclase rocks.

The hypothesis that the massive Cortlaadt rocks were made
by the above-explained method — that is from u ordinary detri-
tus supplemented by materials from the ocean " — is therefore
not wholly improbable. It is still less so when some details
connected with it are considered.

The position of the area — in the angle between the New Jer-
sey and Putnam County Highlands, the site of a Lower Silu-
rian bay — was favorable for the occurrence of the required
conditions. The limestone (dolomite) shows, by its magnesia,
that during the long era in which it was accumulating from
the organic secretions of the waters, evaporating brine-mak-
ing sea-marshes prevailed, or alternated with open seas, over the
shallow bay. The beds of fine mica schist, one to ten feet
thick, which occur intercalated in the limestone, northeast of
Verplanck Point, show that the sea-marshes in some parts be-
came covered at intervals with mud-deposits containing (as the
black mica proves, and also the hornblende and augite present
in some of the schist) iron oxide and magnesia. And, finally,
the occurrence just southwest, at Verplanck Point, in the
same limestone, of conformable intercalations of noryte, pyrox-
enyte and hornblendyte — the massive Cortlandt rocks contain-
ing little of the black mica — and, by the side of these, some
true mica schist beds, accords with the view that in this part
of the area the depositions of common and magnesian salts
from the marsh were at some horizons of the detritus more
abundant than to the northeast. The nearly total absence of
free silica may have its explanation also in these conditions,
since the bases contributed by the sea-water, the soda, magne-
sia and lime, together with the iron from outside sources, would
have needed it to make the silicates. If these are the right
explanations for the facts at Verplanck Point, the principle is

C. U. Shepard — New Meteoric Iron. 119

equally good for all in the Cortlandt and Stony Point area,
and for all 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 against
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 hypotheses, I leave
the subject without expressing a personal opinion.

The Appendix to this memoir, to which allusion has been
made, will appear in a following number of this Journal.

Art. XX. — On a new Meteoric Iron, of unknown locality, in the
Smithsonian Museum; by Charles 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:

The mass was oval in form, with three or four prominent
knobs. Its weight was probably about six pounds. The frag-
ment for examination was separated with considerable facility,
requiring only a few smart blows of the hammer ; and re-
vealed a crystalline structure. The surfaces developed were
partially covered by an exceedingly thin, micaceous layer of
schreibersite. After polishing, the fragment had a somewhat
whiter color than artificial iron. When etched, it showed a
homogeneous, finely crystalline texture, and became still whiter
in color. When viewed at fixed angles of reflexion, the sur-
face glimmered simultaneously, after the manner of sunstone
oligoclasite, thus rendering it probable that the crystallization
of the general mass was that 01 a single individual.

It is obscurely banded, in some portions, with bars about
i^-th of an inch in thickness. But the most remarkable
feature of the etched surface 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

Iron - 92-923

Nickel _ - . 6-071

Cobalt 0-539

Schreibersite (phosphide of iron) .. 0*562 — 100*095

There are traces also of copper and tin. The polished sur-
faces show no tendeny to deliquescence. Sp. gr. =7*589.

Charleston, Feb. 19, 1881.

Am. Jour. Sol— Third Series, Vol. XXII, No. 128.— August, 188\.

120 -1. A. Michelson — The relative motion of Uie Earth

Art. XXL — The relative motion of the EartJi and the Luminif-
erou8 ether ; by ALBERT A. MlCHELSOX. Master, U. S. Navy.

The undulatory theory of light assumes the existence of a
medium called the ether, whose vibrations produce the phe-
nomena of heat and light, and which is supposed to fill all
space. According to Fresnel, the ether, which is enclosed in
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.

Assuming 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 earths 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,
rfj = the distance earth moves, while light passes in the
opposite direction.
Suppose 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
T, = time required for it to pass in the opposite direction.
Further, let T0 = time required to perform the journey if the
earth were at rest.

Then T=£+*=*; and T,= V=4

V V

From these relations we find d=D*f and c?=DTr ,

whence T==^ and ^ = ^-1 — ; T—T. = 2ToTr nearly, and

T-T
V=Y- -1

If now it were possible to measure T— T, since V and T0 are

known, we could find v the velocity of the earth's motion
through the ether.

In a letter, published in u Nature" shortly after his death,
Clerk Maxwell pointed out that T— T1 could be calculated by
measuring the velocity of light by means of the eclipses of
Jupiter's satellites at periods when that planet lay in different
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 velocities, according to Maxwell, is far too small to
measure.

The following is intended to show that, with a wave-length
of yellow light as a standard, the quantity — if it exists — is
easily measurable.

Using the same notation as before we have T = — — and

* V — v

T^-— — . The whole time occupied therefore in going and

returning T4-T,=2Dr^ 5. 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, 2^==2T0. The difference between the

times T-f 1\ and 2T0 is

2DV( ya^— a — yi ) = r 5 T = 2DVyT/y9_

or nearly 2T0^. In the time r the light would travel a dist-

9 9

ance Vr=2VT0^=2D— .

That is, the actual distance the light travels in the first case
is greater than in the second, by the quantity 2D^.

Considering only the velocity of the earth in its orbit, the
ratio TF=rr-rri approximately, and ™=— ,r*^r7^« If D =

V 10 000 rr J> y» 100 000 000

1200 millimeters, or in wave-lengths of yellow light, 2 000 000,

v* 4
then in terms- of the same unit, 2D~= — .

' V9 100

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

4
direction of the earth's motion, will in reality travel — — of a

' J 100

wave-length farther than it would have done, were the earth at
rest. The other pencil being at right angles to the motion
would not be affected.

122 A. A. Micht-lson — The relative motion qftJie Earth

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 -— wave-lengths. The to-
tal change in the position of the interference bands would be —

of the distance between the bands, a quantit}7 easily measurable.*
The 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.

Light from a lamp a, fig. 1, passed through the plane par-
allel glass plate 6, part going to the mirror c, and part being

i. reflected to the mirror d. The

zzi mirrors c and d were of plane

d glass, and silvered on the front

surface. Prom these the light
was reflected to 6, where the
one was reflected and the other
refracted, the two coinciding
along be.
a )/7 /) n e distance be being made

£. equal to bd, and a plate of glass

J g being interposed in the path
of the ray 6c, to compensate for
the thickness of the glass i,
which is traversed by the ray
bd, 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. 3. The same letters refer to the same parts in
the two figures.

The source of light, a small lantern provided with a lens,
the flame being in the focus, is represented at a. b and g are
the two plane glasses, both being cut from the same piece ; d
and c are the silvered glass mirrors ; m is a micrometer screw
which moves the plate b in the direction be. The telescope e)
for observing the interference bands, is provided with a micro-
meter eyepiece, iv is a counterpoise.

In the experiments the arms, bd, be, were covered by long
paper boxes, not represented in the figures, to guard against
changes in temperature. They were supported at the outer
ends by the pins A*, Z, and at the other by the circular plate o.
The adjustments were effected as follows:

The mirrors c and d were moved up as close as possible to
the plate />, and by means of the screw m the distances between
a point on the surface of b and the two mirrors were made
approximately equal by a pair of compasses. The lamp being

and the fjuminiferous Ether.

128

lit, a small hole made in a screen placed before it served as a
point of light; and the plate ft, 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 ft, and when they
were of convenient width and of maximum sharpness, the

Fitr. 2.

sodium flame was removed and the lamp again substituted.
The 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 (/, where the fringes were
rnost distinct. 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 — Tlie 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 pencils.

The apparatus as above described was constructed by
Schmidt and Haensch of Berlin. It wasplaced 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

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 walls
formed the foundation for the pier of the equatorial.

Here, the fringes under ordinary circumstances were suffi-
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 I

If this was the case with the instrument constructed with a
view to avoid sensitiveness, what may we not expect from one
made as sensitive as possible !

At this time of the year, early in April, the earth's motion
in its orbit coincides roughly in longitude with the estimated
direction of the motion of the solar system — namely, toward
the constellation Hercules. The direction of this motion lis
inclined at an angle of about +26° to the plane of the equatar,

and the Luminiferuus Ether, 125

and at this time of the year the tangent of the earth's motion
in its orbit makes an angle of — 23£° with the plane of the
equator ; hence we may say the resultant would lie within 25°
oi 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.

In 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

8 .

— - or 0*16 of the distance between the fringes.
100 &

If, on the other hand, the proper motion of the sun is small
compared to the earth's motion, the displacement should be T\
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 0*000019 and having a length
of about 1000 mm. or 1 700 000 wave-lengths, if one arm should
have a temperature only one one-hundredth of a degree higher
than the other, the fringes would thereby experience a dis-
placement three times as great as that which would result from
the rotation. On the other hand, since the changes of tem-
perature are independent of the direction of the arms, if these
changes were not too great their effect could be eliminated.

It was found, however, that the displacement on account of
bending of the arms during rotation was so considerable that
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
this 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°.

On account of the sensitiveness of the instrument to vibra-
tion, the micrometer screw of the observing telescope could
not be employed, and a scale ruled on glass was substituted.
The distance between the fringes covered three scale divisions,
and the position of the center of the dark fringe was estimated
to fourths of a division, so that the separate estimates were
correct to within T'^.

It frequently occurred that from some slight cause (among

126 A. A. Miokelson — The relative motion of Ike Earth

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
glass plate 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.

S.8, E.

RE.

B.W

"W.

NW.

Remarks.

16-(

1 6-0' 16t

s-i

l(i-|

IS)

13-t

marked B. toward

1?0! 17-C

Vt-t

l«-t

16-I

Stat

•Hli "

1S-I

6th "

13b

1 ;■[■:, i :'.-.'

ia-t

13-(

I3-I

i;m

615

(11 -6 61-S

fiS-[

BR-fi

im-i

.':■! "I

bS-6
120-0
118-0

W. 5G-5
!llB-0

N.E

izo-o

1140

B.JS

60-0
114-0

Excess,

■ SI

: li-i

in*i

II -i

,.,-,

13-0

is-o

(!■!

l t-l

lfi-f)

2d "

itw

JfS-l

i<k

171

il-i

a-n

South.

17-fi

17-h

IT-fi

17-B

I'fti

4t!

IH-II

■1th "

17-15

17-h

17 -t!

17-t

17-fl

17MI

6th

17-0

i n

n-o

1 , i

HVi

3'0

160

7H-I

79-(

79-5

Nl-i

rini

K0-o
168-6

Hlt'O

lfil-ft

U.K.

lfiiMi

&ft

UU'.

164 0

Exeoas,

—3-0

1—4*

Itit revolution

■fl

3"0

3-n

■l'<

fc-S

8-5

West.

II -I

111

IHI

12(

liVI

Ift-J

13-b

MIC

4tii

14-11

atn

4-0

b-0

5-0

5-(

:,-!

S'fi

16-tl

3T-i;

3B-S

SJl-n

38-5

:\'.r.
7 IK,

800

76 5

N.JS.

3G-S
76-0

SB.

38-6

76-n

Excess,

3'j

+ :it

1st revolution 140

■Jl-i

l,VS

17-0

1 l-i

i [■;

N :

16-0

1 IHI

jMH

I**

13C

IH-II

13'(.

13-6

4tli "

1H-II

•i'i-r,

IH-h

IH'fl

IH1I

Sl-fl

Oth

lh-0

•>-fi

16-0

16-U

I..-U

hj-n

16-tJ

16-5

VI -II

8.1 76-6

7("t-'i

H.K.

73-6

ft-R

78-5

147-5

l+7!i

ifia-o

i«a-6

Excel*, 1

+ 8-0

-Hi-.",

and the Luminiferous Ether. 127

The heading of the columns in the table gives the direction
toward which the telescope pointed.

The footing of the erroneous column is marked x, and in the
calculations the mean of the two adjacent footings is sub-
stituted.

The numbers in the columns are the positions of 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 E. and W., the excess is called
positive. The excess of the footings of N.E., S.W., over
those of N.W., S.E., are also called positive. In the third
and fourth series this is reversed.

The 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.

Series 1 +0*017 +0050

•' 2 -.-0-025 -0*033

" 3 +0*030 +0030

" 4 +0-067 +0-087

4 J 0*089 0137

Mean = +0*022 +0*034

The displacement is, therefore,

In favor of the columns N.S + 0-022

" 4I 4t N.E., S.W +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.

The 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) with 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 right.

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
eliminate this gradual change, we may expect a much smaller
error. This is most readily accomplished as follows:

Adding together all the footings of the four series, the third
and fourth with negative sign, we obtain

N. N.B. E. S.E. S. S.W. W. N.W.

31-5 31*5 26*0 245 23'0 20*8 180 110

128 A. A. Michehon — The relative motion of ttie Ekirth, etc.

or dividing by 20x12 to obtain the means in terms of the
distance between the fringes,

N. N.E. E. S.E. S. S.W. W. N.W.

0*131 0-131 0108 0-102 0*096 0*086 0*075 0*046

If x 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 = 9'25a + 64-5

If, now, we construct a curve with ordinates equal to the
difference of the values of y found from the equation,, and the
actual value of y, it will represent the displacements observed,
freed from the error in question.

These ordinates are :

N.E.

S.E.

S. S.W.

W. N.W.

-*002

-•011

+ •003

-001

— •004 — 003

— 001 +-018

-•002

+ •003

N.E. --011

N.W. +-018

-•004

-•001

S.W. -*003

S.E. -*001

Mean =

: --003
+ •001

+ •001

Mean= — -007
+ •008

+ •008

Excess

= -•004

Excess =—015

The small displacements — 0*004 and -0*015 are simply errors
of experiment.

The results obtained are, however, 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 in fig. 4.

■**■

The dotted curve is drawn on the supposition that the dis-
placement to be expected is one-tenth of the distance between
the fringes, but if this displacement were only yj^, the broken
line would still coincide more nearly with the straight line
than with the curve.

The interpretation of these results is that there is no dis-
placement of the interference bands. The result of the
hypothesis of a stationary ether is thus shown to be incorrect,
and the necessary conclusion follows that the hypothesis is
erroneous.

This conclusion directly contradicts the explanation of the
phenomenon of aberration whfch has been hitherto generally
accepted, and which presupposes that the earth moves through
the ether, the latter remaining at rest.

E. S. Holden — Light 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,
that the ether moved quite freely through the solid mass of the
earth. Still it would have been satisfactorv, if it had been
possible to have put the two theories to the test of some
decisive experiment"

In 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 as
Night- Glasses ; by Edward S. Holden.

In the Philosophical Transactions for 1800, vol. xc, 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 could 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 Cfark 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 K & Holden — Light of' Telescopes used us Night-glasses.

for the Insane, which is 20,798 feet distant from the center of
the Dome.* 1" at this distance is 1*3 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 bv
W. V, Shipman, Esq., of Chicago. I have marked upon th*e
cut the line of the horizon, from which it appeal's that the

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 C, (9 feet), as " the base
of the spire ;" the next section, (13 feet high), as " the cupola "
or "the dome," and the remaining portion, as "the tower."

The finder has an aperture of 3'50 inches, a field of 1° 20',
and a magnifying power of 26 diameters. The refractor has
an aperture of 15o6 inches, a field of ll''(i, and a power of 195
diameters.

The following observations were niijdc 1881, April 18, by
Mr. S. W. Burnham and myself:

The whole sky was perfectly clear except a very faint bank
of clouds to the west of the tower looked at. The observations
were as follows : tin. standing for observations made by
Holden ; ft for those made by Burnham.

E. S. Holden — Light of Telescopes used as Night-glasses. 131

7h 35ro. The tower disappears to the naked eye. In the finder
the spire is still plainly seen. In the 15-inch, the whole of
the spire, ribs, domo and many details well seen. — Hn.

*7h 42m. The tower disappears to the naked eye. In the finder
and telescope everything still seen. — fi.

8h 0m. 15 inch: the ribs on the cupola are gone. — Hn. and fi.

gh /jm Finder : the shape of the cupola is confused and uncer-
tain.— Hn. and fi.

gh 24m Finder: pretty much the same. 15-inch: the spire on
top of the cupola is still plain. No one looking with the
telescope would miss it. — Hn. and fi.

8h I7m. 15-inch : the spire on top of the cupola gone. — Hn. I
still see it. — fi.

gh j /7m Finder: all shape to the cupola is gone. — Hn.

8h 21m. 15-inch: spire still seen by averted vision; not well by
direct. — fi.

gh 22m. Finder: the tower is a mere black spot. 15-inch: spire
is much fainter. — fi%

8h 23m. 15-inch : the spire is gone, except that I can see that the
outline of the cupola is not round. — fi.

Sh 25m. 15-inch : spire gone. — fi.

gh 26^. Finder : tower gone. — Hn.

gh 27m Finder: tower and cupola gone. — fi.

gh 27m. 15 -inch: tower and cupola gone. — Hn.

gh 2$m, 15-inch: tower has lost all shape. — fi.

8h 30m. 15-inch : tower gone. — fi.

About this time the sky was dark and the horizon became
clearer as was shown by small stars becoming visible in the
finder. Probably the light cloud above spoken of was dissipated.

8h 35m. 15-inch : the cupola and tower can be plainly seen as a
dusky cloud with a certain shape, when the telescope is vibra-
ted to and fro. — Hn. and fi.

8h 37m. 15-inch: same. — Hn. and fi.

8h 43m. 15-inch : the cupola and tower are seen even better than
before. The horizon is clearer. There is no difficulty in see-
ing them when the telescope is moved, and they can just be
seen by direct vision. — fi.

8h 44mg same. — Hn. and fi.

8h 45m. Stopped examination as there seemed to be no prospect
of losing the tower as long as the horizon remained clear. If
we had lost it we should have attributed the loss to haze at
the horizon. Small stars 8-9 magnitude seen in finder.
They must have had an altitude of not more than 30'.

It appears to me that this confirmation of Herschel's 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 Night-glass, nor of the similar effect when
large apertures are used.

Washburn Observatory, Madison, 1881, May 1.

132 Whitfield and Dawson — Nature of Dictyophyton.

Art. XXIII. — On the nature of Dictyophyton; by R P. Whit-
field. With a note, bv 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-
glass of moderate power it is seen to have been composed of
cylindrical threads of various sizes, now replaced by pyrite.
With 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
2£ 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 narrow,
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 further description
and illustration of the form I shall defer to a future occasion,
but shall here designate the species as Uphantaenia Dawsoni
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 these threads and spicules are well set forth
in Dr. Dawson's notes below, and the spongoid features and
relations to Euplectella indicated.

Note by Dr. J. W. Dawson on the Structure of a specimen of
Uphantaenia, from ilie 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 6mm in length and 4 or 5

Whitfield and Dawson — Nature of Dictyophyton. 133

in breadth. The longitudinal bands are about 3""" broad, the
transverse bands much narrower. Some of the rectangular in-
terspaces are of the color of the matrix ; others wholly or par-
tially stained with dark matter. The meshes are nearly black,
but in a 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 to a point, but
usually seem quite cylindrical and smooth. In their present
state they appear as solid shining rods of pyrite. The largest
spicules are about T|ff of an inch in diameter; the smaller
scarcely one-fourth of that size. The spicules of the transverse
bands cross those of the longitudinal ones without any organic
connection. Among the long spicules of the bands can be sfeen
multitudes of very minute and apparently short spicules confu-
sedly disposed, and these abound also in the dark-colored areoles.

On the whole the structures are not identical with those of
any plant known to me, and rather resemble those of siliceous
sponges of the genus Euplectella.

The 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
and so are also calcareous shells, especially when they contain
much corneous matter, but such changes are not usual with
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. I have specimens of
Actyhspongia from the Niagara formation which have thus been
replaced by matter of a ferruginous color; and in a bundle of
fibers probably of a sponge allied to Hyalonema from the
Upper Llandeilo 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 as more probably a sponge.

I owe the opportunity of examining this very interesting
specimen to the kindness of Professor Whitfield.

134 77. Draper — Photographs of the Spectrum of tike OomeL

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
had been directed to the more delicate branches of celestial
photography and spectroscopy, such as photography of stellar
spectra and of the nebulae. More 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 was obvious that if the comet could be photographed by
less than an hour's exposure, there would be a chance of ob-
taining a photograph of the spectrum of the coma, especially
as it was probable that its ultra-violet region consisted of but
few lines. In examining my photographs of the spectrum of
the voltaic arc, a strong band or group of lines was found
above H, and on the hypothesis that the incandescent vapor of
a carbon compound exists in comets this band might be photo-
graphed in their spectrum.

Accordingly, at the first attempt, a photograph of the nucleus
and part of the envelopes was obtained in seventeen minutes
on the night of June 24th, through breaks in the clouds. On
succeeding occasions, when an exposure of 162 minutes was
given, the tail impressed itself to an extent of nearly ten
degrees in length.

I next tried by interposing a direct vision prism between
the sensitive plate and object glass to secure a photograph
which would show the continuous spectrum of the nucleus
and the banded spectrum of the coma. After an exposure of
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 would be serious after passing through the slit,
two prisms and two object glasses, yet the advantage of being
able to have a juxtaposed comparison spectrum would make
the attempt desirable, and moreover, the continuous spectrum
being mord weakened than the banded by the increased disper-
sion the latter would become more distinct.

0. A. Young — Spectroscopic Observations upon the Comet 136

Three photographs of the comet's spectrum have been taken
with this arrangement with exposures of 180 minutes, 196
minutes and 228 minutes, and with a comparison spectrum on
each. The continuous spectrum of the nucleus was plainly
seen while the photography was in progress. It will take
some time to reduce and discuss these phptographs and pre-
pare the auxiliary photographs which will be necessary for
their interpretation. For the present it will suffice to say thai
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 h and another between h and H. I 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 strengthen the hypoth-
esis of the presence of carbon in comets ; but a series of com-
parisons will be necessary, and it is not improbable that a part
of the spectrum may be due to other elements.

271 Madison Avenue, New York.

Art. XXV. — Spectroscopic Observations upon the Comet b, 1881 ;

by Professor C. A. Young.

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.

For 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 Grubb — the latter with
dispersive powers varying, according to occasion, from two to six
dense glass prisms. The telescope was the 9£ inch Equatorial.

The following are the principal facts made out so far :

(1.) The spectrum of the nucleus was found to be for the
most part simply continuous; but on several occasions, espe-
cially June 25, July 1, and July 12, it showed distinct bands,
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 strongly.

(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. Sol— Third Series, Vol. XXII, No. 128.— August, 1881.

136 C. 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.
The 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 the 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-de6ned, so much so as to in-
terfere with satisfactory measurements of position. After July
1 the definition became better.

(5.) 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 spark 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,
and on July 1, 2, 3, 6 and 12.

All the comparisons concur in showing a close, and so far as
the dispersive power employed could decide, an exact agreement
between the spectrum of the comet and that of the Bunsen
flame. On the other hand the discordance between the comet-
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, \ = 5629* ± 4*0
Lower edge of middle band, X = 5164*9 ±0*6
Lower edge of upper band, A = 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 3, showed

W. Hdrkness — 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 hardly necessary to say that the evidence as to the
identity of the flame and comet spectra is almost overwhelming;
the peculiar ill-defined appearance of the cometary bands at the
time of the comet's greatest brightness is, however, something
which I have not yet succeeded in imitating 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 spectroscopes upon the sun in preparation for evening
work. I find that the one-prism spectroscope shows the bright
lines in the 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 ITs
as bright lines to a person unused to the spectroscope, but with
this instrument they are perfectly obvious — even obtrusive.
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.

Art. XXVI. — Note on the Observations of Comet 6, 1881, made
at the United States Naval Observatory ; by Wm. Bareness.

[Communicated by authority of Rear Admiral John Rodgers, U. S. N.,

Superintendent.]

On the evening of June 28th, T 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 bv 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 image prism, and subsequently with
a Savart polariscope, but neither of these instruments showed
any polarization. Mr. Huggins thinks he has detected the

188 W. Harkness — Observations on Comet 6, 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 43*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. The spectrum
of the nucleus seemed to be continuous, and its approximate
extent was from D to G. I did not detect anv Fraunhofer
lines in it, but possibly they may exist and yet have been
obliterated by the rather wide opening of the slit, which was
0*0125 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*3, 5124 and 467*2. This seems to be
the ordinary comet spectrum. The 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
hoziness 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*8 and
512 4.

made at the United jStaie? Naval Observatory. 139

On June 28th the cornet's nucleus was about as bright as a
third-magnitude star, and its tail was plainly visible throughout
an extent of at least twelve degrees. On July 1st the comet
was perceptibly fainter, and its tail was only about eight de-
grees long, but perhaps this was partly owing to the moon, five
and a half days old, oeing above the horizon. On July 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.
Rock thought he could trace it for rather more than twenty
degrees.

Since the 10th inst, Professor Hall has examined the comet
with the twenty-six inch refractor, and Professor Eastman has
examined it with the nine and six-tenth inch refractor, but
neither of these gentlemen have been able to see any indica-
tions of a division of the nucleus.

The comet was observed 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 desire to compute
the orbit, Professor Eastman has furnished from these observa-
tions, the following positions, which are uncorrected for parallax
and aberration time :

ishingl

,on Date.

Bight Ascension.

Declination.

June

265

5h 48m 38«04

+ 57° 40' 52"'0

July

1'5

6 22 46 *85

70 39 57 -6

' »

3*5

6 42 32 -92

74 5 16 -2

6 5

7 20 36 88

77 49 56 3

10*5

8 27 31 -84

+ 80 48 56 l

From a Cambridge observation of June 23d, and the Wash-
ington observations of June 29th and July 5th, Professor
Frisby has computed the following parabolic elements :

Perihelion Time, June 16*3700
7T = 265° 31' 15"-4 1
Q = 270 58 27 "0 I Equinox

i = 63° 25' 55"-7 [ 1881*0
log q - 9-866748

The residuals, C—O, for the middle place are

M cos p=- 13" 4
<5/3 = + 62 -1

It is a matter of interest to note that about June 20th the
earth was in the immediate vicinity of the comet's tail, but I
have not made sufficiently accurate computations to be able to
state whether or not it actually passed through it.

U. S. Naval Observatory, Washington, July 13, 1881.

140 L. Boss — Observations on Oie Comet 1881 b.

Art. XXVIL— Observations on the Comet 1881 b; by Lewis

Boss.

News of the sudden appearance of a great comet in the
northern sky first reached me through the local newspapers on
June 23 ; but that night was cloudy. On the evening of June
24, the comet was occasionally seen for a few moments at a
time, through intervals in clouds, but never with sufficient
clearness to admit of satisfactory examinations as to its physical
appearance. One micrometric comparison between the comet
and DM 50° 1225 was secured with the thirteen-inch refractor.
The comet was plainly visible to unassisted vision in a clear
sky at sixteen hours mean time, and then appeared as bright
as Capella.

Owing to an accident which happened to the equatorial dur-
ing my absence, I have thus far been unable to secure addi-
tional micrometric comparison by that instrument At lower
culmination the comet has usually been hidden by clouds, and
the hour is now very inconvenient ; so that I can report only
the following observations of apparent position :

D. 0. M. T. App. a. App. 6.

June 24d 9h 59m 318 5h 39m 14«*2 + 49° 59' 20"- Filar micrometer *

June 26 11 26 51 5 48 35*53+57 39 05*2 Transit circle.

June 28 11 30 26 6 00 00*69+ 63 43 31*8 Transit circle.

July 8 12 42 38 7 51 49*54+79 34 03*0 Transit circle.

Prom the first three positions reduced to 1881*0 and corrected
for parallax and aberration by means of values of d from a
preliminary orbit, I derived the following parabolic elements.

T = 1881, June 16*1358. Washington M. T.

7T 265° 01' 38" )

8 270 58 45 [ 1881*0

i 63 30 27 )

to* q 9*86510

Middle place, C-O. Jvt cos /?, +4". J/9, -7". We also. have
with the same elements: July 8, C—0. JX cos j9, +30".
J/9, — 75". The elements therefore are not likely to be found
greatly in error.

The similarity of the elements of this comet with those de-
duced by various computers for the comet of 1807, has already
been much discussed in the newspapers. The difference of
about three degrees in the position of the nodes, and especially
the great difference in the respective values of q (which amounts
to *087) seems larger than can well be ascribed to errors of
computation, or possible planetary disturbance.

* Star of comparison DM 50° 1225, position obtained from Argelander's north-
ern zones combined with Bonn VI. Aa on three wires ; A<5, one measure.

L. Boss— Observations on the Comet 1881 b. 141

It seems to me more likely that these two comets may have
formed parts of the same body in distant ages, and that these
parts may have separated as Biela's comet did. The two parts
would need to have but slightly differing mean distances from
the sun in order eventually to reach the amount of separation
which now exists between the perihelion passages of tne 1807
and 1881 comets. A great number of similar, though generally
less striking resemblances among cometic orbits have been
noted, in. cases where absolute identity between the two comets
considered seems impossible. These cases increase the demand
for a general explanation, such as I have suggested above.
The resemblances seem to be too close and too frequent to be
considered the result of chance; and the above hypothesis
seems to have some support in reason and experience. If the
comet of 1881 proves to have a periodic time between one and
two thousand years the plausibility of this hypothesis will be
very much strengthened.

I have been too much pressed with other duties to give close or
systematic attention to the physical characteristics of the comet
The nights of June 26, June 28, July 1, 8 and 13 were unusu-
ally favorable for such studies here. The atmosphere was un-
usually transparent on June 26 and I then traced the tail for a
distance of nearly forty degrees from the nucleus. On that
night there were two branches. The longer and brighter
branch was perfectly straight. The other curved, with its
concavity toward greater right ascension. On the next clear
night (June 28) the straight branch was of about the same
length as the curved one, and was a thin and scarcely percep-
tible streak. On July 1, the two branches seem to have
merged into one, presenting a shorter and broad fan-like ap-
pendage, perfectly straight and strongly marked on the preced-
ing side, concave and nebulous on the following.

On all occasions the nucleus under a power of 250 has
seemed to be quite distinctly defined and star-like in appear-
ance. On June 26, its measured diameter was 7"; on July 8,
this had become 2". The latter measure reduced to the dis-
tance of June 26 becomes 3"3, a rather surprising reduction in
the diameter, if it be real.

Dudley Observatory, Albany, N. Y., July 19, 1881.

142 A. W. Wright — Polarization of Light from Comet 6, 1881.

Art. XXVIIL— The Polarization of Light from Comet ft, 1881 ;

by Arthur W. Wright.

Polariscopic observations of the comet were made on the
evenings of June 25 and 26, which gave faint indications of the
existence of polarization, but with the instruments then used it
was not possible to ascertain satisfactorily either its character or
amount The state of the sky was not very favorable for ob-
servation until the evening of June 29, when a method of
observation was found which made it possible to determine the
polarization, which was at once seen to be considerable, with
comparative ease and a good degree of precision.

The instrument employed was the polarimeter constructed for
observation of the solar corona in the eclipse of July 29, 1878,
and described in the volume containing the reports upon this
eclipse issued from the U. S. Naval Observatory.* A slight
modification was made by substituting a Savart plate for the
selenite, it being attached to the Nicol's prism in tne eye-piece.
This gave a rather narrow field which was nearly filled by the
image of the comet, an arrangement very favorable for detec-
tion of the bands caused by polarization. The aperture of the
telescope to which the polarimeter is attached is tnree inches.

The plane of polarization of the light was found to have such
a direction as to pass through the sun's place. This was deter-
mined both by the disposition of the bands seen in the polari-
meter, and ako independently by means of a double-image
prism placed before the ordinary eye-piece of the telescope
when this was attached to the instrument The two images of
the comet as the prism was rotated were easily seen to have
different intensities in certain positions corresponding to polari-
zation in a plane situated as above described. As seen with
this instrument the fainter of the images appeared considerably
shorter than the other as if the light coming from toward the
extremity of the tail were more strongly polarized than that
from points near the nucleus. But this was possibly an
illusion depending upon the fact that when the very faint light
was diminished by the polarizing effect it became too feeble for
perception, and this lessened the extent of the visible area.
When examined with the polarimeter the light appeared to be
slightly less strongly polarized as the instrument was directed
to points more remote from the head of the comet, as would be
the case if the proportion depended simply upon the angle of
incidence of the light, which decreased with the distance from

* Reports on the Total Solar Eclipses of July 29, 1878, and January 11, 1880,
pp. 264-267.

A. W. Wright — Polarization of Light from Comet b, 1881. 143

the nucleus. The second and third of the observations of July
1, in the list below, were made upon regions removed several
degrees from the nucleus, but though the amount of polarization
is somewhat less, and tends to confirm the above conclusion,
the difference is hardly greater than would be accounted for by
the errors of observation. Determinations of polarization at
great distances from the nucleus were not possible, the light
being too feeble.

In the use of the polarimeter, the latter Was fitted so that a
card could be attached to the slide moving the glass plates.
The positions were pricked upon this with a needle point, and
were read off by means of the graduated circle after the obser-
vations were finished. The latter were made in sets of ten, the
plates being moved to the point of neutralization, or disappear-
ance of the bands, first from below, then from above, alternately,
until five had been made from each direction. The points upon
the card thus fell into two groups separated by an interval
which was greater or less according to the degree of polariza-
tion. The mean of the angles for each set of five being taken,
the percentage of polarized light corresponding to each was
determined from a curve constructed for the instrument. Two
values were thus obtained the mean of which was the amount
of polarization for the point observed. Each card was capable
of containing two sets of points, and could be removed or re-
placed by another without the aid of a light, a necessary pre-
caution in observations of such delicacy, as the proper sensi-
tiveness of the eye could only be maintained by seclusion from
the light

The results of the observation are given in the following
table. The date and local mean time for the series of each
evening are given in column I. In column II are given the
results derived from the sets of determinations arranged in their
order as made, each result, as explained above, being obtained
by ten measurements. The numbers express the proportion of
polarized light to the total light reckoned as one hundred parts.
The means of the percentages of the sets in column II for each
evening are given in column III. Column IV gives the
approximate angles of incidence of the light derived from the
sun, referred to the nucleus or points very near it. It is
obtained from the ephemeris of Peters,* combined with that of
Oppenheim given in the Dun Echt Circular No. 24. The
angles subtended at the comet by the earth's radius vector at
the dates of the ephemeris were obtained by a simple graphic
process. With these a curve was constructed from which the
angles for the dates of the different observations were derived.
These divided by two are the angles of incidence.

* Astronomische Nachrichten, No. 2381, p. 75.

144 A. W. Wright — Polarization of Light from Comet 6, 1881.

I.
June 29, lh to 2h, A. M.

247
23*8
21-3

nx
23*3

nr.
60°-5

June 30, lh to 2h, a. m.

181
17*6
186
17*1

17*8

•

58°

Julyl, llh to 12h30m p.m.

21-8
201
176
17-7

193

54°5

July 2, 10h 30m to llh p.m.

169
169

169

52°*5

•

July 3, 10h 30m to 12h P.M.

183
18-0
18*7

18*3

51°

July 21, llh 30mP.M. to lh.

15-9
156

15*7

33°

July 22, llh 30m P.M. to lh.

14-5
13-8

14*1

32°

The observation of July 2 was made under rather unfavorable
atmospheric conditions, and the sky was somewhat luminous
from auroral action. The amount of polarization found is
undoubtedly less than the true value. The others were made
when the sky was very clear, and during those of July 21 and
22 it was exceptionally fine. The time of the observations
precluded the possibility of any influence from twilight or the
light of the moon.

On comparing the percentage of light polarized and the
angles of incidence it is seen that they decrease together. No
definite maximum was made out, but the existence of one near
or beyond 60° is perhaps indicated by the fact that polarization
was less easily observed on the evenings previous to June 29,
and by the more rapid variation in the percentages on this and
the two succeeding evenings. At first sight the large percent-
ages obtained in the earlier observations appeared to indicate
reflection from a gaseous substance, but the numbers found
later, and especially the relation of all the values to the angles
of incidence, render an inference as to the character of the
reflecting material more difficult. It is not improbable that
the constitution and physical condition of the matter composing
the tail were variable, and this circumstance would introduce
changes in the proportion of polarized light, in addition to
those produced by the alteration in the angle of the reflected
rays. The fact of polarization shows that a large part, probably
the greater part, of the light coming from the tail is reflected
sunlight.

Yale College, July 25, 1881.

Chemistry and Physics. 145

SCIENTIFIC INTELLIGENCE.

I. Chemistry and Physics.

1. On Ozone as a cause of the Luminosity of Phosphorus. — Vari-
ous writers, especially Joubert, have called attention to the con-
nection of the phenomena of phosphorescence with ozone. To learn
something of the nature of this connection, Chappuis has studied
the effect of ozone upon the luminosity of phosphorus in the pres-
ence of oxygen. Fourcroy had long ago observed that in pure
oxygen at a temperature of 15° and under atmospheric pressure,
phosphorus is not luminous in the dark. Chappuis now finds that
under these conditions a bubble of ozone introduced into the bell
jar produces the phosphorescence, though only momentarily, the
ozone being destroyed. Moreover, it is not the vaporization of the
phosphorus which determines the phosphorescence, but the com-
bustion of this vapor, the entire space occupied by the oxygen at
first appearing luminous, the solid becoming so only after all the
vapor has been burned by the ozone. Two cylinders, one contain-
ing air, the other pure oxygen, were inverted over two dishes
containing iodide of potassium and starch solution. A fragment
of phosphorus was plunged into each gas, in contact with the
liquid. In the first, the phosphorus became luminous and the
solution became blue. In the second neither phenomena appeared.
Whenever the phosphorescence appeared, ozone was present ; and
whenever ozone was absent there was no luminosity. Moreover,
the author calls attention to the fact that certain bodies which
have the power of preventing this luminosity of phosphorus are
precisely those bodies which destroy ozone or are destroyed by it.
Oil of turpentine for example, which is the most active, destroys
ozone completely. In a balloon containing air, phosphorus and
turpentine, a bubble of ozone produces light for a second only, the .
ozone being destroyed by the turpentine, but burning a part of the
phosphorus vapor also. On adding the ozone the luminosity ex-
tends throughout the space and at last the solid phosphorus only
remains luminous. Hence the author regards the production of
the luminosity of phosphorus in oxygen, as one of the most deli-
cate of the reactions for ozone and proposes to employ it in subse-
quent researches. — Bull. jSoc. Ch.^ II, xxxv, 419, April, 1881.

G. F. B.

2. On the appearance of Nitrous Acid during the Evaporation
of Water. — Warington has submitted to the test of careful ex-
periment Schonbein's statement that whenever pure water or an
alkaline solution is evaporated, nitrite of ammonium is produced,
and concludes that " it is undeniable that pure water if evapora-
ted to a small bulk, by ordinary means, will generally be found to
contain nitrous acid." A sample of rain water which gave no
reaction to the metaphenylenediamine test, after concentration to
one quarter of its bulk, showed the reaction distinctly. A liter of
distilled water, with 5cc. lime water, evaporated to a small volume

146 Scientific Intelligence.

over a Bunsen burner gave a strong reaction. The importance of
this result, with reference to the determination of nitrites in natu-
ral waters, led to an investigation of the cause of this result. First
it appeared that a liter of distilled water evaporated in a retort,
either exhausted or at atmospheric pressure, gave no reaction for
nitrous acid, and hence proved the air to be the source of the con-
tamination. Another liter with 5cc. lime water, was evaporated in
a glass basin 6J inches in diameter over a Bunsen rose burner. The
reaction given was strong and corresponded to about 0*05 mgrm. of
nitrogen. Since a second similar evaporation conducted with
steam gave only 0*004 mgrm. nitrogen, it was clear that the
nitrous acid had mainly come from the combustion of the gas used
as fuel. But still even in the residue obtained with steam, the
rose-color appeared. That this came directly from the air of the
room was shown by placing a second basin of distilled water by
the side of the first during the evaporation. After twenty-four
hours a full rose tint was developed ; and this without any sensi-
ble evaporation. For extremely accurate work, water then must
be evaporated in close vessels ; but for ordinary purposes, the con-
centration may be effected in a steam bath.

Warington gives in his paper some experiments made with the
naphthylamine test for nitrous acid, proposed by Griess, which
show an extraordinary delicacy. The solution to be tested was
slightly acidified with hydrochloric acid and a few drops of an aque-
ous solution of sulphanilic acid and of a similar solution of naph-
thylamine hydrochloride were added. The nitrous acid if present
forms a diazo-compound, which the naphthylamine converts into a
body having a beautiful rose color. The tests for delicacy were
made in test tubes, the column of liquid being about three inches
deep. To lOcc. of the solution were added one drop of HC1 (1 : 4)
one drop of a nearly saturated solution of sulphanilic acid and one
drop o£a saturated solution of naphthylamine hydrochloride. The
standard solution was made with potassium nitrite prepared from
pure silver nitrite. With a solution of 1 part of nitrogen as nitrous
acid in 1,000,000 parts of water an immediate pink color appeared
which rapidly became deep ruby red; in 10,000,000 parts, at once
a pink, and at the end of an hour a full rose; in 100,000,000 parts
a pink tinge in six minutes and a pale pink in an hour; in
500,000,000 parts (lcc. of the millionth solution in a half liter of
water) showed a pink tinge before two hours, and in twenty-four
hours the three inch column showed it ; 1,000,000,000 parts using
ten drops of the reagents, showed an alteration of tint in two
hours, and a distinct pink color in twenty-four hours. In the last
two experiments similar flasks to which no nitrite had been added
were similarly treated, but without result. During the reading of
the paper in the Chemical Society's room, the presence of nitrous
acid in the air was shown by exposing 200cc. of water containing
the test, to the atmosphere there in a basin for four hours. On
pouring it into a cylinder, it had become rose-pink as was seen on
comparing it with a similar cylinder which had been closed with a

Chemistry and Physics. 147

watch glass. In the open air at the Rothamsted farm, nitrous acid
was detected by this air test. In six days the reaction appeared
in water exposed to this air, and in twenty-seven days it con-
tained one part of nitrogen in 15,000,000. In rain water the
naphthylamine test readily shows nitrous acid, except when the
rains are exceptionally heavy. — J. Chem. Soc.y xxxix, 229, May,
1881. G. F. B.

3. On Boron hydride. — Jones and Taylor have examined
with care the preparation and properties of the boron hydride
discovered by the former in 1879. Three methods of preparing
magnesium boride were used : 1st, the action of recently ignited
boric oxide, finely powdered, upon magnesium dust ; 2d, the
direct union of magnesium and boron ; and 3d, the action of
magnesium on boron trichloride. Though the two latter methods
yielded a purer product, the first was the more convenient. The
magnesium boride is placed in a flask with a little water and
strong hydrochloric acid is added. The evolved gas may be col-
lected over water or mercury. It is boron hydride mixed with a
large quantity of hydrogen. In this condition it is a colorless
gas which has an extremely disagreeable and characteristic odor,
producing nausea and headache, is slightly soluble in water, which
does not decompose it, burns with a splendid green flame, produc-
ing boric oxide, is decomposed by passage through a red-hot
tube, depositing a brown film of boron, and depositing boron on
a porcelain plate held in its flame, is decomposed when passed
through a solution of silver nitrate giving a black precipi-
tate containing boron and silver, and is oxidized to boric acid
by potassium permanganate solution. With ammonia it gave a
compound decomposed by acids. On analysis the boron appeared
to be combined with 2*86 parts H ; confirming the formula
BH8. — J. Chem. Soc, xxxix, 213, May, 1881. g. f. b.

4. On the Purification of Carbon Disulphide. — Allary has pro-
posed a simple, rapid and effective method of purifying carbon
disulphide. This consists in covering it with a layer of water to
which, from time to time, portions of a concentrated solution of
potassium permanganate are added. The whole is strongly agi-
tated after each addition, the process being stopped when the
reduction of the permanganate is no longer produced, and the
water retains its purple color. After washing several times, the
disulphide is obtained free from water by means of a separating
funnel, and filtered through a thick dry paper. Redistillation is
seldom necessary. The odor is etherial and not at all disagree-
able. It should be kept in the dark. — Bull. Soc. Ch., II, xxxv,
491, May, 1881. g. f. «.

5. Electric Absorption of Crystals. — Professor H. A. Rowland
and Mr. E. H. Nichols discuss the question whether there should
be electric absorption in a perfectly homogeneous medium.
The theory indicates that there should be none, and the writers
have tested the point by experiment, and it was found that
Iceland spar had no electric absorption. This substance can be

148 Scientific Intelligence.

regarded as perfectly homogeneous. The writers consider that the
apparatus which they used will be of value in testing the perfect
homogeneity of insulating bodies. — Phil. Mag., June, 1881, p.
414. j. t.

6. Transmission of radiation of low refrangibility through
Ebonite. — Captain Abney and Colonel Festing have repeated
the experiments of Professor Bell which showed that invisible
rays of heat, of low refrangibility, pass through ebonite, by
exposing a sensitive photographic plate to these radiations.
An image was formed in many cases and the writers conclude
that the coefficient of absorption of a plate of ebonite ^ of an
inch in thickness is equal to 1*8 and that any rays which can
penetrate through £ of an inch of ebonite will only have an in-
tensity of ifl6lUo6 of that of the resultant beam without deduct-
ing anything for the scattering of the light. It is concluded
" that ebonite when of small thickness transmits to some extent
the rays of low refrangibility." — Phil. Mag.y June, 1881, p. 466.

J. T.

7. Conservation of Electricity. — M. G. Lippmann continues
his paper on this subject — see Comptes Pendus, May 2, 1881 —
and maintains that the principle of the conservation of elec-
tricity stands in the same relation to electricity that Carnot's
principle stands to heat. — Comptes Pendus, p. 1149, No. 20, May
16, 1881. j. t.

8. Seating of Ice. — A. Wuilner repeats the experiments of
Carnelley and concludes that so long as the bulb of the ther-
mometer is wholly surrounded with ice the thermometer indicates
no temperature above — 3° C. The thermometer with its bulb
encased in ice was placed in an air-tight test tube, which was
enlarged by a connecting tube of glass ending in a larger recep
tacle; the air contained in this could be raised or lowered in
temperature and thus the temperature of the air in the test tube
could be modified. When this air was heated by a Bunsen
burner the thermometer rose quickly to — 3° C. The ice vapor-
ized quickly ; when the bulb of the thermometer ceased to be
completely surrounded by ice the temperature rose to 0° C, and
when the thermometer bulb became more free from ice the tem-
perature rose very quickly as the ice vaporized. Wtlllner con-
firms the observation of Carnelley that the thermometer under
these conditions could rise from 20° C. to 30° C. above zero
and pieces of ice still be observed hanging to the thermometer
bulb. — Wied. Annalen der Phgsik und Chemie, No. 5, 1881, p.
105. J. T.

9. Atomic Weight of Cadmium. — Mr. Oliver W. Hunting-
ton, of Harvard, has made a study of the atomic weight of
cadmium, following the method used by Prof. Cooke with refer-
ence to antimony. The mean result from his first series of experi-
ment is 112*31 ; and from a second, 112-32.

Geology and Mineralogy.

II Geology and Mineralogy.

1. Terraces and ancient Coast lines (" Strandlinien") ; by
Karl Pettersen. Published in Norwegian, at Tromsi), in
1880, and translated into German by Dr. R. Lehmann, Zeitsch. f.
d. gesammt. Naturwissenschaften, liii, 1880. — Prof. Pettersen has
carried on an extended series of observations of the system of
terraces in northern Norway. The region examined extends from
north to south about 60 English miles and an eqnal distance from
east to west, embracing the fiords and sounds in the neighbor-
hood of Tromso (lat. 70 N.). A portion (about one-fourth) of the
map accompanying his article is reproduced in fig. 1, of the same
scale as the original. The terrace system includes first the proper
terraces of loose material, sand, gravel and so on, and secondly
the " strandlinien " or coast lines which are worn out of the solid

rock. Each of them consists of two parts, the more or less level
upper surface, and the slope which bounds it in front (see £, and
*ii *n si 'n nS- 4)- *■ survey of all the results of observation
shows that these bench lines occur at almost every height from
the lower limit up. Between the bench lines at 139 and 42'7
meters above the sea the average difference in height of any two
successive lines is only 2'2 meters, while the maximum is never
greater than 3'8 ; above the upper limit named the same may be
true but the number of lines observed is smaller.

Figure 1 represents these several lines at the different points on

160

Scientific Intelligence.

the coast near Troraso, and figs. 2, 3, 4 give sections at three
points (see also fig. 1), which may fairly be taken as typical.
Figure 2 is from Sandvik, where are three levels, namely, 14*5,
31*6 and 35*4 meters above the mean sea surface (in the figures
the heights are given in Norwegian feet) ; the lowest has a maxi-
mum breadth of 1 9 meters. Fig. 3 is a section at a point between
Sandvik and Grepstad, where the three levels are 14*5, 34-1 and
38*5 meters. Fig. 4 represnts a section at Grepstad where there
are only two levels, namely, 14*5 and 38*4 meters.

Sanrfuik

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Gnej9&tiz<&

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. 1

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: : A

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t^fffvl

It is concluded, in the first place, that the terraces and " strand-
linien " do not, taken as a whole, follow definite levels. Some of
them are local and are observed only for short distances, while
others extend along for many miles. The latter are more typi-
cally developed, are more connected with definite levels, and may
be traced as such for long distances in Northern Norway. The
formation of these was probably in part determined by periodic
changes in climate. The course of any particular line is nearly
horizontal, whether it runs parallel with the coast, or extends from
the coast into the interior, although the highest levels are found
in the interior of the fiords. The conclusion of Bravais (1842)
that these lines are not horizontal but rather rise in level toward
the interior, upon which the idea of a gradual secular elevation
of the land, joined with an unchanged level of the sea, has been in
part based is not accepted as generally true. That the wearing
action of the sea has been the only cause in producing the results
observed is not regarded as probable, and this conclusion is sup-
ported by several arguments ; what other forces were instrumental
in producing the result is not distinctly stated. The formation of
the " strandlinier" must have begun at the upper edge of the
downward slope and the excavation gone on from above down
while the land rose slowly in reference to the surface of the sea.
The apparent elevation of the land is regarded as having gone on
gradually and slowly and not suddenly and interruptedly. In
general these changes in level which went on along the coast of
northern Norway during the post-glacial time are believed to be
most easily explained by the supposition of a changing level of
the sea.

2. On the mibatanees obtained from some "Forte vitrifife" in
France. — M. Dauhrke lias made a critical mineralogical and

Geology and Mineralogy. 151

chemical examination of materials obtained from several " Forts
vitrifies" in different parts of France. This name is given to the
walls or to the simple debris of walls, whose materials have been
fused together by the action of fire.

The substance obtained from the neighborhood of Argentan
was of a dark greenish brown color, opaque, and resembled
certain slags. A section examined under the microscope revealed
the presence of large numbers of crystals of an octahedral mineral,
probably spinel, and also crystals of melilite, both formed by the
process of fusion. An analysis showed a considerable amount of
alumina and of soda, leading to the inference that the fusion had
been accomplished by adding marine salt to the aluminous silicate
in the clays and schists. Some partially fused granitic rocks
from the forts of Ch&teau-vieux and of Puy de Gaudy (Creuse),
also from the neigborhood of Saint Brieuc (C6tes-du-Nord), were
especially examined. The specimens consisted of small fragments
of the granite, some angular, others more or less rounded,
and all forming a solid mass, with a glassy surface. They were
in some cases similar in appearance to volcanic scoria.

When sections of the granite were examined in the microscope
it was found that the orthoclase still acted upon polarized light, and
the aibite also was nearly unaltered, but besides them there were
vitreous masses produced by the fusion. Of the minerals formed
by the process, spinel was very common in regular octahedrons,
sometimes transparent, sometimes opaque. There are also large
numbers of microlites in geodes in the fused mica, which are
probably to be referred to a triclinic feldspar. The small quan-
tity of fluorine originally contained in the mica is regarded as
having played an important part in the changes accompanying
the fusion. These granites had been fused immediately by fire
without the aid of soda, as in the first case named, and it is
reasonably certain that the process of fusing together the small
fragments was intentional although the means by which it was
accomplished so thoroughly is less easy to understand.

3. Preglacial Outlet of the Basin of Lake Erie into that of
Lake Ontario. — Mr. J. W. Spencer discusses this subject in a
paper published in the Proceedings of the American Philosophical
bociety for 1881. He reaches the conclusion that a deep channel
passed off from the southern part of Lake Huron along the course
of the present valley of the Au Sable, pursued an east-southeast
course and entered the basin of Lake Erie west of Vienna, bent
around Long Island (east of Vienna), and then took a north-by-
west course to Ancaster in the Province of Canada, whence it fol-
lowed an easterly course along Dundas Valley into the west end of
Lake Ontario; and that this channel was in preglacial time the out-
let of Lake Erie into Lake Ontario. The supposed channel is now
buried beneath drift. In the Dundas Valley (which is bounded
by vertical escarpments) the drift has been, penetrated to a depth
of 227 feet below the surface of Lake Ontario. He also endeavors
to show that the Great Lakes owe their existence to subaerial and

Am. Jour. Sol— Third Series, Vol. XXII, No. 128.— August, 1881.

152 Scientific Intelligence.

fluviatile agencies, but not to glacier excavation. The memoir is
accompanied by two maps of the region.

4. laccoliths (or Laccolites) in Japan. — Mr. G. H. Kinahan
has described Laccolith-like intrusions of eruptive rocks in Coun-
ties Wexford and Wicklow, Ireland. They occur in highly
disturbed Cambro-Silurian strata of different kinds, and the latter
are baked or altered for some distance about them. — Geol. Mag.,
March, 1881.

5. Iron Ore of Iron Mine HiU, Cumberland, Rhode Island.
— Mr. M. E. Wadsworth describes this " titaniferous iron ore " —
a titaniferous magnetite — as containing in its ground-mass large
crystals of a triclinic feldspar along with chrysolite in grains, and
mentions its resembling the Taberg iron ore rock of Sweden.
Part of the chrysolite is changed to serpentine. An analysis of
the ore by Prof. R. H. Thurston obtained 9*9 per cent of titanium.
The rock nearest to the iron ore-bed is mica schist " some hun-
dred feet away." Mr. Wadsworth supposes the iron ore to be of
eruptive origin. (Mus. Comp. Zool., vol. vii ( Geol. Series, vol. I).

It is of importance to note that a chrysolitic magnetite occurs
at the O'Neil Mine, Monroe, Orange County, New York, the
chrysolite of which was first determined and described by Prof.
Brush, who gave it a distinctive name, hortonolite, on account of
the amount of manganese present. As the iron ore deposits of
Sussex County, New Jersey, and Orange County, New York, con-
stitute beds conformable to the adjoining schist, and are, as Prof.
G. H. Cook, of New Jersey, states, after extensive investigation,
of metamorphic origin, it is probable that the Rhode Island
magnetite is also metamorphic. j. d. d.

6. Brazos Coal-field, Texas. — A paper on this Texas coal-field,
by C. A. Ashburner, is published in the Transactions of the
American Institute of Mining Engineers, for 1881. The coal
field proper in the southwestern part of the " Missourian or Fourth
bituminous coal-basin of the United States" in which are two
workable beds 2£ to 6 feet, are 85 feet thick, and are included
between an upper sandstone and conglomerate, representative of
the Millstone grit or Pottsville conglomerate (No. XII of the
Pennsylvania series), and a lower gray limestone representative of
the Mountain limestone, or Chester and St. Louis limestone, of the
Mississippi Valley.

1. Report of the Geological Survey of Pennsylvania, on the
causes, kinds and amount of waste in mining Anthracite (num-
bered A2), by Franklin Platt; with a chapter on the Methods
of Mining, by J. P. Wetherell. 134 pp. 8vo, with thirty-five
figures of mining operations, a plan of an anthracite breaker, also
a specimen sheet of the work of the survey in the Anthracite Coal
Field. — The specimen sheet of the anthracite coal-field, appended
to this very important and well illustrated report, is by C. A.
Ashburner. It contains a section on a large scale, exhibiting the
stratification and flexures of the beds, and also a corresponding
ground plan or map view, giving the topographical features of the

Geology and Mineralogy. 153

region, and the actual positions and structure of the several
"veins" (beds), as explored.

Mr. Ashburner, in a paper read before the American Institute of
Mining Engineers, states that his plan includes the exhibition on
the sheets, besides surface features, underground contour curve
lines of the chief coal-beds in the individual districts, the area
worked out, and that under development of the contoured bed, all
gangways, tunnels, adits, overlying and underlying the contoured
bed, represented by a conventional color and line for each bed ; so
that the maps will give the areas worked out and undeveloped, the
structure and positions of the beds, the amount of coal, and the
probable structure of the undeveloped areas.

8. Land-plants in the Middle Silurian of North Wales. — Dr.
Henry Hicks describes (Proc. Geol. Soc., May 25, 1881), remains
of Lycopodiaceous plants referred by him to Dawson's genus
Psilophyton, spherical bodies resembling the Pachytheca of Sir J.
D. Hooker, and numerous minute bodies supposed to be micros-
pores of LycopodiacesB, besides seaweeds, from the Denbighshire
grits, near Corwen, in North Wales. The associated graptolites
were, according to Mr. Hopkinson, partly Middle and partly Upper
Silurian forms, some being Llandovery species, here dying out, and
others, Wenlock species, first appearing here.

9. Vertebrata of the Permian Formation of Texas, by E. D.
Cope. — No. 32 of Prof. Cope's Paleontological Bulletin contains
Plates I to IV of remains oiEryops megacephalns, V, oiEmpedias
molarfo, and VI of Dimetrodon incisivus, which are published
also in the Proceedings of the American Philosophical Society,
vol. xix, p. 56 (see this Journal, xxi, 407). In the American
Naturalist for February last he has published a list of the Fishes,
Batrachians and Reptiles of the Permian of the United States,
numbering in all 51 species.

10. Life-History of Spirifer lmvis% by Prof. Henry S. Williams,
Ph.D. — Prof. Williams's paper on Spirifer laevis, an abstract of
which is given in the twentieth volume (1880) of this Journal, has
been published in full in the Annals of the New York Academy
of Sciences, vol. ii, No. 6.

11. Geological Society of London, — At the annual meeting of
the Geological Society in February, the Wollaston gold medal was
presented to Prof. P. Martin Duncan ; the Murchison medal to
Prof. Archibald Geikte ; the Lyell medal to Dr. J. W. Dawson,
of Montreal ; the Bigsby medal, to Prof. Morris.

12. On the Optical Characters and Crystalline System of some
important Minerals. — The results obtained by the more exact
methods of investigation employed in mineralogy in the past few
years have led to the change of a considerable number of min-
erals to systems of a lower grade of symmetry than those to
which they had previously been assigned. The classical memoir
of Mallard (Ann. des Mines, vol. x, 1876) has had a strong influ-
ence in this direction. In it he sustained this change for some of
the best known species and those which had been accepted as types

154 Scientific Intelligence.

of the systems to which they were referred ; for example, garnet,
vesuvianite, fluorite, apophyllite, zirkon, apatite, beryl, tourma-
line, and so on. Mallard suggested, in explanation of cases like
those named, the hypothesis that such crystals were to be con-
sidered as twins or compound crystals so made u|5 as to have a
pseudo-symmetry corresponding to a higher grade than that be-
longing to the individuals themselves.

T'he question as to the sharpness of the line dividing the crys-
talline systems from each other, and in many cases as to which
system a given species really belongs, cannot be said to be de-
cided at the present time. It is certainly possible to exaggerate
the " optical anomalies" and to attribute to them a morphological
significance when they are in fact due simply to accidental causes,
such as the internal tension produced at the time the crystal
was formed. For example, the species boracite, long held as a
typical hemihedral form in the isometric system, although with
an anomalous optical character variously explained, has by Mal-
lard, and others been referred to the orthorhombic system. Re-
cently, however, Klein (Jahrb. Min., 1881, 239) has shown by the
effect upon the optical character produced by heating sections of
the crystals that the peculiarities are probably due to internal
tension simply, and that there is nothing which really conflicts
with its being referred to the isometric system. Similarly, anal-
cite, the common form of which was long held to be a typical
example of an isometric trapezohedron, was afterward referred
to other systems by Schrauf, Mallard, Lasaulx and others, and
finally referred back to the isometric system by several mineralo-
gists who have reached the same result by somewhat different
methods. Other similar examples might be given.

M. Bertrand, working from the standpoint of M. Mallard, has
recently published some interesting contributions to this subject.
He shows that the apparently isometric octahedrons of ralstonite
exhibit two optic axes with an angle of about 90°. He has
also examined a series of minerals ranging from the pure lead
phosphate, pyromorphite, to the lead arsenate, mimetite ; the
conclusion is that while the first is truly hexagonal and has
one negative optic axis, the other is really orthorhombic, and
owes its apparent hexagonal form to twinning. A section of
mimetite from Johanngeorgenstadt, cut normal to the vertical
axis, was seen in polanzed light to be made up of six triangles,
each having as a base the side of the hexagon ; the two optic
axes make an angle of 64° in air. Between the two extremes
there are various intermediate compounds containing both P906
and AsaOB, and it is found that as the proportion of As Ob dimin-
ishes, the angle of the optic axes also diminishes. Similar results
have been obtained by M. Jannettaz. These facts recall the results
obtained by Cooke with crystals of iodide of antimony, who
proved the existence of a uniaxial (hexagonal) and a biaxial (ortho-
rhombic) variety, of which the latter changes into the former on
a slight elevation of temperature. M. Bertrand has also studied

Geology and Mineralogy. 155

several varieties of garnet and arrived at results essentially the
same as those of M. Mallard. Sections of crystals of aplome,
ouvarovite and topazolite show two optic axes with an angle of
about 90°. The ouvarovite is regarded as made up of twelve
pyramids having the faces of the crystal as their base and their
vertices at the center. The dodecahedrons of aplome and topaz-
olite are explained as formed of forty-eight simple crystals.
Further than this, he found it possible to separate the dodecahe-
drons mechanically into these forty-eight individuals, each one
of which is truly biaxial ; the fracture-surfaces are smooth and
make angles of 60° with the rhombic faces when the plane of
separation obtained is parallel to the side of the rhomb, and of 90°
when it is parallel to one of the diagonals. The former fractures
are obtained more readily than the second, and it is concluded
from this that the union of the four crystals which form together
the same rhombic face is more intimate than that of the twelve
complex rhombohedral pyramids among themselves. That this
is the true explanation of these facts may perhaps be questioned.

13. Brief notices of some recently described minerals. — Chal-
comenite. A new species described by M. DesCloizeaux, from
the Cerro de Cacheuta, south-east of Mendoza, Argentine Repub-
lic. It occurs in transparent crystals, and in thin crystalline
crusts of a blue color; it is associated with a compact mineral
of a violet color, and having, according to M. Pisani, the compo-
sition (Cu„ Pb)Se. The crystals belong to the monoclinic sys-
tem and are generally combinations of the prism (I/I = 108° 20'),
and the orthopinacoid and basal plane (i-i/ O =90° 51'). The
plane of the optic axes is parallel, and the acute negative bisectrix
perpendicular to the horizontal edge O/i-i. The axial angle is
small, and the ordinary dispersion (p < v) so great that with a
green glass the lemuiscates have the form of circular rings with
a black cross, while with a blue glass they become elongated
ellipses, normal to the plane of polarization of the microscope, and
with the hyperbolas separated about 10°, at 45° with this plaue.
The composition of the new mineral has not been fully deter-
mined, owing to lack of material, but preliminary trials by M.
Damour show it to be essentially a hydrated selenite of copper. —
C. K, April 4, 1881.

Tritochorite. Described by Frenzel, locality unknown. Phy-
sical character as follows : Massive with columnar structure ;
cleavage longitudinal, tolerably distinct, yielding thin plates ;
H. =3*5 ; G. =6*25 ; color blackish brown, with lighter yellowish
brown spots ; streak pale lemon- vellow. An analysis yielded :
V90 24-41, As906 3-76, PbO 53*90^ CuO 7*04, ZnO 11*06 =100-17.
— Min. Petr. Mitth., iii, 506.

Lautite. Also described by Frenzel, from the mine Rudolf-
schacht at Lauta, near Marienberg, Saxony. Occurs massive
with columnar, fibrous, or granular structure. IT. = 3-3*5 ;
G. = 4*96 ; luster metallic ; color iron-black ; streak black. An
analysis gave: As 42*06, S 18-00, Cu 27'66, Ag 11*74=99-40.

156 Scientific Intelligence.

This corresponds with Cu4AgAs6S6. Associated with native ar-
senic, pyrargyrite, chalcopyrite, tetrahedrite, galenite and barite.
— Ibid., p. 515.

Serpierite. M. DesCloizeaux has given the name serpierite
to a new mineral from the zinc mines of Laurium, Greece. It is
found in minute dark greenish blue tabular crystals, belonging to
the orthorhorabic system. They have the base 0 broad, and
show, also, the prism (1^1=98° 42'), the pyramid 1 (O | 1
= 115° 32'), and several brachydomes. The plane of the optic
axes is parallel to the longer diagonal of the base ; the axial angle
for red glass is 44° 20' in oil, or 67° 10' for air. M. Bertrand
has obtained similar results. According to preliminary trials by
M. Damour, the mineral is a hydrous basic sulphate of copper and
zinc. — Bulletin Soc. Min. France, iv, 89, 1881.

Schneebergite. This mineral occurs in minute transparent
octahedrons, of a honey-yellow color and vitreous to adamantine
luster. II. =6*5 ; G. =4*1. It consists mostly of lime and anti-
mony, with iron and traces of other elements ; related to romeite.
Found by Lhotsky on the Schneeberg in the Tyrol, associated
with anhydrite (or gypsum), chalcopyrite and magnetite; par-
tially described by Brezina. — Verh. geol. Reichsanstalt, 1880,
No. 17.

" Tyre kite." One and a half hundred weight of the " carne-
lian marble" of Tyree, Scotland, dissolved in sixteen gallons
of hydrochloric acid left as residue, thirty pounds of sahlite, a
little scapolite and sphene, and some ounces of a red mud. By
decantation 1*9 grams of powder of a deep brick red color was
obtained. Of this mud, sulphuric acid dissolved *78 grams, leav-
ing 1*1 insoluble. The last was analyzed and decided to be an
impure talc. The soluble portion yielded: Fe„08 38*22, Al2Os
8-23, FeO 3-16, MnO 0'39, MgO 29*94, CaO 2*21, H90 12*47,
Pa06 4-71, SiOa 1-02 =100*35. To this last obviously heterogene-
ous substance the new name is provisionally given by Heddle ;
certainly no name was ever given with less reason. — Mineralogi-
c<U Magazine, iv, 189, 1881.

Fredrictte. A variety of tennantite, or arsenical tetrahedrite,
from Fahlun, Sweden, described by H. Sjogren, peculiar in con-
taining both lead and tin. H. = 3'5 ; G = 4*65; color iron-black;
a brilliant metallic luster. An analysis gave: As 17*11, Sb tr.,
S 27*18, Cu 42*23, Pb 3*34, Sn 1*41, Ag. 2'87, Fe 6*02 = 100*16.—
Geol. For. Fork. Stockholm, v, 82, 1881.

Arctolite. A mineral described by Blomstrand, as collected
in 1861, on "Nordskon" near Spitzbergen. It forms thin irregular
plates in marble. H. = 5 ; G. = 3.03 ; colorless, or yellowish to
greenish. An analysis gave : SiOa 44*93, TiOa 0*38, AlaOa 23-55,
Fea08 1*24, CaO 13*28, MgO 10*30, NaaO 1*73, KaO 0*79, H90
:j*54 = 99 74. It is probably to be regarded as an altered
hornblende. — Ibid., p. 210.

Frigidite. A variety of tetrahedrite from the Valle del
Frigido, Apuan Alps, described by D'Achiardi. It is usually

Geology and Mineralogy. 157

in compact granular masses, rarely crystallized. H. a little less
than 4; G. =4*8; luster metallic; grayish-steel colored. An
analysis hy Dr. Funaro gave, after deducting 2*2 p. c. SiOa and
calculating to 100: Sb 27-00, S 31-23, Cu 20-39, Fe 13-37, Ni 7'97,
Ag 0-04, Zn tr. = 100.

DuMORTiiiRiTE. Found sparingly in small crystalline grains in
the gneiss of Beaunan, valley of the Azeron, south-east of Lyons.
It has a bright blue color, and the specific gravity is 3-36. It has
been examined chemically by M. Damour, and shown to be a
silicate of aluminum, with perhaps the composition [AlJ4Si3018 ;
this point, however, is not entirely established. M. Bertrand
finds that it has distinctive optical characters similar to those of
andalusite.

14. On the mineral Dawsonite from luscany. — The rare species
dawsonite, described by Dr. Harrington in 1874 as occurring
sparingly near Montreal, nae been found by M. Chaper at Piau
Castagnaio in Tuscany and has been investigated by M. Friedel.
It is found in thin plates radiated and formed of fine fibers in a
quartzose rock impregnated with dolomite. An analvsis gave :
COa 29-59, A1208 35-89, Na90 19-13, HaO 12*00, MgO'l-39,' CaO
0*42. This corresponds closely with the results of Harrington
but the material in hand seems to have been purer. This analysis
agrees closely with the formula NaJAl ]C908 + 2HO, w hich may
be written 3(NaaC03) + (AlaC309) + 2(Hfl[Al9]0 j.— Butt, Soc. Min.
France, iv, 28.

15. Vanadium minerals from Cordoba, Argentine Republic. —
The occurrence of vanadium minerals at several points in the State
of Cordoba has been described by Brackebusch (Las Especies
Minerales de la Republica Argentina, 1879). Crystals of des-
cloizite and vanadinite from this locality have been figured by
Websky (Ber. Ak. Berlin, July and October, 1880). He shows
that the vanadinite has the same hemihedral characters as apa-
tite, the crystals being highly modified and showing the planes,
O, 7, e-2, 1, 2-2, and 3-f. Rammelsberg (ZS. G. Ges., xxxii, 709)
has analyzed the descloizite and obtained for dark colored crys-
tals. G. = 6*080: Va05 22-74, PbO 56*48, ZnO 16*60, MnO 1-16,
H96 2-34, CI 0-24. This corresponds to the formula R4Va09 or
R3V908 + RHaOa with R=Pb : Zn = l : 1, and makes the species
analogous in composition to olivenite and libethenite.

Occurring with the descloizite and vanadinite is a mineral in
small black striated prismatic crystals, for which Dr. Doring pro-
poses the name Brackebuschite. An analysis by him yielded : —
Va05 25-32, POs 0-18, PbO 61-00, MnO 4-77, FeO 4-65, ZnO 1-29,
CuO 0-42, H90 203 = 99-66. For this Rammelsberg calculates the
formula R8 V208 + aq., which (Mn : Fe= 1 : 1 ) requires : — VaOB 25*45,
PbO 62-09, MnO 4-95, FeO 5-01, Kfi 2*50=100.

16. Zinn : Eine geologisch-montanistisch-historische Mono-
grafie; von E. Reyer. 248 pp. 8vo. Berlin, 1881 (G. Reimer). —
Dr. Reyer has already published a series of papers devoted to the
subject of tin, treated both from the geological and the technical

158 Scientific Intelligence.

standpoint. In this volume he has brought together a very large
amount of useful matter. The introduction contains a very com-
plete list of memoirs previously published. The subject is divided
geographically, the tin-mining districts of Bohemia and Saxony
coming first, then those of Cornwall, Burma, Siam, Australia and
Tasmania. The geology is treated briefly and concisely, in part
in connection with each locality, and more fully in a resume at
the close. The larger part of. the volume, however, is devoted to
a history of the tin-mining, and here much valuable information
has been brought together.

III. Botany and Zoology.

1. Marine Algce of New England and adjacent coast ; by W.
G. Farlow, M.D. (Reprinted from Report of IT. S. Fish Com-
mission for 1879.) Washington, 1881. 8vo, pp. 210, tab. xv. —
Hitherto the only good work attempting to describe ail the sea-
weeds of our coast has been the Nereis Boreali- Americana of Dr.
Harvey, published by the Smithsonian Institution in three quarto
volumes from 1852 to 1858. This work took in the seaweeds of
the entire coast of the United States, Pacific as well as Atlantic.
Since it appeared the industry of collectors has detected many
additional species along the several portions of our coasts, and the
acumen of Phycologists at home and abroad has given us much
information respecting the true structure, physiology and affinities
of many of the forms already known. In the present work Pro-
fessor Farlow has limited himself to the seaweeds known on or
near to the coast of New England ; but the systematic classifica-
tion which he has adopted, and the many interesting and new
points of structure and function which he has either discovered
for himself, or has accepted from the writings of Thuret, Bornet,
Agardh, Le Jolis, Rostafinki, etc., render the work a valuable
text-book for the study of marine Algae wherever the .English
language is read.

The old classification of Algae was into the three sub-classes of
Melanospermece, Rhodospermece or Floridece and Chlorospermew.
Within thirty years the disposition of the Floridem has met with
no fundamental change, but the Melanospermece and the Chloro-
spermece are no longer recognized in their integrity. The sexual
reproduction of the IPucacew is now as well understood as that of
Rosacew, and is clearly of an oosporic character; that is, the
unfertilized nucleus is fertilized by antherozoides after exclusion
from the conceptacle. But no sexual reproduction of Lamina-
rieai) Punctariece, Dictyosiphoniece, Desmarestiece, and their allies
has been detected, and it is very doubtful whether any exists.
These tribes are therefore grouped in the suborder Phmosporece^
and united with Chlorosporeat, Bryopsidece and Botrydiew, all
grass-green Algae, in the order Zoosporece,

The obscure Chroococcacece and Nostoclinew form also a sepa-
rate order, the Cryptophyceoe. Thus Professor Farlow recog-
nizes four orders, Cryptophycece, Zoospore^ Oospores and JFlori-

Botany and Zoology. 159

dew. Aii ample explanation of this system is given in the twenty-
four pages of introduction, where one may look in vain for a
recognition of the conjoining of Algae and Fungi in chlorophyllose
and achlorophyllose branches of common classes, as was proposed
by Cohn and Sachs, and set forth in Professor Bessey's " Botany
for High Schools and Colleges." It is certainly pleasant to the
student of Algae to be relieved from having to consider the objects
of his study not a distinct class or group of classes, but only chlo-
rophyll-bearing equivalent of Fungi, and so but halves of an
uncoraprehended and ill-assorted whole ! It is still more reassur-
ing when this relief comes from the laboratory of one so learned
in the physiology of both Algae and Fungi as Professor Farlow.

In the quarter of a century which has elapsed since the appear-
ance of Harvey's Nereis, but one conspicuous red Alga has been
discovered on our coast and that one is Nemastoma Bairdii, of
which Professor Farlow found but a solitary specimen at Gay
Head in 1871. The principal changes in nomenclature among the
Floridece are the substitution of Rhabdonia tenera for Solieria
chordaliSy of Rhodophyllis Veprecula for CaUiblepharis ciliata,
and of Griffithsia Bornetiana for G. corallina. Rhodomcla
gracilis and R. Rochei are reduced to forms of R. subfusca and
Folysiphonia formosa to P. urceolata. Harvey knew certainly of
no Coralline on the Jfew England coast. But Corallina officinalis
is very common, and Professor Farlow has recognized, in addition,
five species of Melobesia and two of Lithothamnion. There are
two or three added species of Fxicus, and F. nodosus is excluded
from the genus, to become Ascophyllum nodosum. Sargassum
Montagnei is very properly retired. Among the great Laminarice
are some changes : L. dermatodea and X. borea together consti-
tute Saccorhiza dermatodea, the genus differing from Laminaria
principally in the form of the hold-fast and in the presence of cryp-
tostomata. X. platymeris is added, X. saccharina and X. digitata
retained, though with some apparent hesitation, X. longicruris
fully recognized, and X. Fascia, referred to the genus Phyllitis in
Scytoriphoniece.

There are several changes among the filamentous Chlorosporeve,
and still more that is new (to Americans at least) among the
membranous forms, the genus Monostroma, with four species, being
introduced, and the species of Ulva arranged after Le Jolis in the
" Liste des Algues Marines de Cherbourg." The Cryptophycew were
but indistinctly known to Dr. Harvey, but are now satisfactorily
arranged in sixteen genera, among which only Oscillaria, Micro-
coleus, Lyngbya, Calothr ix and Rivularia are given in the Nereis.

The Diatoms and Desmids are not treated of in this work.

The fifteen plates at the end of the volume are mainly illustra-
tive of the different kinds of fructification seen in Algae, and add
much to the ease with which one may comprehend the principles
of classification here set forth.

It is to be hoped that the able botanist who has given us this
most important contribution to the history of North American

160 Scientific Intelligence.

Algae will before long publish a similar report on the seaweeds of
the Pacific Coast, and then a comprehensive work on all North
American Marine Algae. d. c. baton.

2. Das System der Medmen von E. Hceckel; Zweite hdXfte. —
The conclusion of the first part of " Haeckel's System der Medu-
sen," devoted to the Acraspedae, Steganophthalmae, or the Dis-
cophor® in their widest sense, has been issued.

Though some of the orders adopted by Haeckel differ but
slightly from those previously recognized, they are invariably
baptized anew, and we find in this, as in all the systematic work
of Haeckel, a deliberate disregard of the nomenclature adopted by
his predecessors. Haeckel stretches the laws of nomenclature to
their extreme limits, and nothing can render them more ridicu-
lous than such a systematic nomenclature as that of the System
d. Medusen. Every genus, every family, every order, in fact,
every division or subdivision adopted, invariably receives a new
name if its limits are either greater or smaller than those of the
corresponding division previously known to science. The same
principle would warrant us in rebaptizing any well-known animal,
provided some important point of its structure, unnoticed hereto-
fore, were described in detail and made to form the basis of the
new-fangled name by which it is hereafter to be known. Nomen-
clature is properly an aid in ascertaining the views of our prede-
cessors, and in limiting and in defining the existing state of the
knowledge of a group ; its main object is not the introduction of
new terms, and an endless confusion, merely in order to glorify
the peculiar systematic views of the latest philosophical writer
on the subject. This defect to which we had already called
attention in the first part of the System is far more prominent in
the second part, where the material is less complete, and is
derived, for the greater part, from alcoholic specimens of Medusae
which Haeckel has had no opportunity to study from life. We
may close this part of the subject by asking Medusologists what
is gained by the fabrication of such names as Stauromedusae and
Cubomedusae ?

Haeckel adopts, with Huxley and nearly all the later writers on
Medusae, the group of Lucernaridae, and one of his most interest-
ing new types is the genus Tessera (from specimens collected by
the Challenger). This genus shows the close systematic affinity
existing between the Lucernaridae proper and the true Dis-
cophorae. It is, in fact, nothing but a free Lucernaria. Closely
allied to them are the Peromedusae. To this group belong a
number of large Medusae, which probably live on the bottom in
deep water. Several species were collected by the " Challenger,"
and the " Blake "* dredged off the N. E. extremity of George's
Bank a number of specimens of Dodecabostricha (Brandt), Peri-
phylla (Steenst.).

Haeckel establishes (from alcoholic specimens) several genera
and families of this interesting group of Medusae, and gives an

*See Bull. M. 0. Z., vol. viii, No. 9, 1881.

Botany and Zoology. 161

excellent anatomy of their more prominent details, hitherto only-
known from the drawings of Mertens and the descriptions of
Steenstrup. It seems to us as if Haeckel had needlessly multi-
plied not only the families, but even the genera of this group.
(Compare Pericolpa and Periphylla.)

Among the Charybdeidae we must call special attention to the
interesting genera Procharybdis and Chirodropus. These are
specially important as bringing the Charybdeidae into closer sys-
tematic relationship to the other Diseophorae.

In the next order, the Disco-Medusae, he adopts the primary
subdivisions of the group Semeastomae and Rhizostonwe proposed
by Agassiz. Although he prefaces his review of that classification
by stating that it is entirely unnatural, he at once, after remov-
ing some of the forms included in these divisions into other fam-
ilies, proceeds to adopt it. Haeckel makes a most characteristic
attempt to show that Agassiz willfully neglected to quote Hux-
ley's paper on the anatomy and affinity of the family of the
Medusae. (See p. 27 Contrib. Nat. Hist. U. S., vol. iii, where
Huxley's paper is quoted.) Naturalists who willfully ignore or
misrepresent the work of their colleagues are fortunately more
rare than those who are known to manufacture drawings to suit
their pet theories. Haeckel, of course, differs from Agassiz radi-
cally in his estimate of the value of the homojogy between
Acalephs and Echinoderms. His view may be " grundf alsch "
according to Haeckel, but it certainly is not yet so considered by
those embryologists who have the best right to an opinion on
the subject.

The first subdivision adopted by Haeckel (in addition to those
mentioned above), the Cannostomae, can hardly be considered cred-
itable to a zoologist having so extensive a knowledge of Acalephs
as Haeckel. This subdivision is based entirely upon a few alco-
holic specimens of Diseophorae, any one of which may turn out
to be the young stage of some unknown Diseophorae. Of the
Cannostomae, Haeckel has examined only two species from living
specimens ; the other sixteen are based upon alcoholic material,
which, no matter how well preserved, will not give even a
Haeckel an idea of their ontogeny. Among the Semeastomae we
find the new family of Flosculidae, including Floscula and
Floresca — genera which are probably closely allied to embryonic
Pelagiae and the new family of Ulmaridae: the genera Ulmaris,
Umbrosa and Undosa, allied to embryonic Aureliadae.

Among the Rhizostomidae Hreckel gives, with other new gen-
era, good figures of Archirhiza and of the family of Versuridse
(Versura, Cannorhiza). Among the Crambessidae, a family which
Haeckel established in 1869 upon a new species of Rhizostoma,
are illustrations of Leptobrachia and Thysanostoma. This same
species of Crambessa ( C. Taji) subsequently formed the subject of
an excellent monograph by Grenacher and Noll, which added
greatly to our knowledge of the Rhizostomae.

The majority of the plates of the second part of Haeckel's

162 Scientific Intelligence.

Acalephs are drawn from the alcoholic material which was
placed at his disposal by nearly all the European museums. These
illustrations suffer as compared with those of the Hydroids, where
Haeckel had a large amount of new, fresh material at his disposal.

The value of this monograph is, however, very great, as it has
cleared the ground of a great deal of rubbish and will enable the
future investigator to work upon a comparatively firm basis.

Discophorous Medusae are by no means as common as Hydroids ;
their habits are as yet but little known ; though they are often
found in swarms upon the ocean, it is usually under circumstances
which render their capture or detailed examinations at the time
impossible. I well remember laying off the Bar of San Francisco
for a number of days and seeing the greater number of the
species of Discophorae, so well figured by Mertens, float by out of
reach, only near enough to be roughly identified, while it was
impossible, on account of the rolling of the schooner, to examine
properly the few I was fortunate enough to capture. Fortunately,
as Haeckel's monograph has well shown, a great part of their struc-
ture can be made out from carefully preserved alcoholic specimens,
and until some naturalist, under more favorable circumstances,
gives us anatomical details drawn from life, to these we must look
for the principal additions to our knowledge of the Discophorae.

A list of the fossil Medusae thus far described is added to the
volume, and a few appendices, making corrections and additions
of imperfectly known Medusae. It closes with a final appendix
containing a puerile attack on Metschnikoff, evidently suggested,
as Haeckel naively says, by the fact that " Metschnikoff bei jeder
Gelegenheit meine zoologische Arbeiten auf das hef tigste schmaht
und angreift," and that Metschnikoff insists, with other Russian
naturalists, in writing in his own language. It certainly is a pity
that Russian naturalists will not follow the example of the
Scandinavians and give us French or English resumes of their
memoirs. But no nation, least of all the German, has a right to
ask the most active embryologists of the present day to write to
suit their convenience. The day may yet come, in spite of
Haeckel, who evidently does not appreciate Chinese and Japanese
civilization, when their investigators also will have as good a
right to be heard as the Russians by all except the close corpora-
tion of naturalists of whose claims Haeckel is the exponent.

A. AG.

3. New and little known Reptiles and Irishes in the Collections
of the Museum of Comparative Zoology; by S. Garman. Bull.
Mus. Conip. Zool., vol. viii, No. 3. pp. 85-94. Cambridge, 1881.

4. On the Results of Dredging under the supervision of Alexan-
der Agassiz along the Atlantic Coast of the United States dur-
ing the Summer of 1 880 by the Steamer Blake. Report on the
Cephalopods, and on some additional species dredged by the
U. S. Fish Commission Steamer Fish Hawk in 1880, by A. E.
Verrill. Ibid., vol. viii, pp. 95-230. Also, Report on the Sela-
chians, by S. Gabman. Ibid., pp. 231-284.

Astronomy. 163

5. Arrangement of the JPerissodactules, with a note on the
Structure of the foot of Toxodon, by E. D. Cope. — Proceedings
of the American Philosophical Society, April 15, 1881.

IV. Astronomy.

1. Photographic Spectrum of Comet 1881, b; by Wm. Huggins.
— On Friday night (June 24th), I obtained with one hour's exposure
a photograph on a gelatine plate of the more refrangible part of
the spectrum of the comet which is now visible. This photograph
shows a pair of bright lines a little way beyond H in the ultra
violet region, which appear to belong to the spectrum of carbon
(in some form) which I observed in the visible region of the
spectra of telescopic comets in 1 866 and 1 868. There is also in
the photograph a continuous spectrum in which the Fraunhofer
lines can be seen. These show that this part of the comet's light
was reflected solar light.

This phdtographic evidence supports the results I obtained in
1868, showing that comets shine partly by reflected solar light,
and partly by their own light, the spectrum of which indicates
the presence in the comet of carbon, possibly in combination
with hydrogen. — Communication from the Author; also Nature,
June 30.

2. Notice of the Comet; by Charles E. Burto.n. — At about
llh. 0m. G.M.T. on June 29, a transit of the "following" nuclear
jet of the great comet over a star of 8m. was observed by Mr. N.
E. Green, of 39 Circus Road, St. John's Wood, and by me, with
a 12^-inch reflector belonging to Mr. Green. Definition was very
good and tranquil. As the star became involved in the jet it
gradually increased in size, and, when seen through the brightest
part of the jet traversed, resembled an ill-defined planetary disk
about 3" in diameter. At this moment the comet seemed to have
two nuclei similar in aspect and brightness.

The effect of the cometary matter on the star's image resembled
that of ground glass, not that of fog; the image of the star, being
dilated into a patch of nearly uniform brightness, instead of pre-
senting a sharp central point with a surrounding halo. Cirro-
stratus, passing into rain-cloud, produces on the appearance of
the sun an effect the counterpart of that produced by the come-
tary emitted matter on the star. There was not sufficient light
for the use of the spectroscope, the star, afterwards identified as
B.D. +65°, 519, being fainter than 8m.

The transit of the jet occupied about 3m. and the star slowly
resumed its ordinary appearance and dimensions, the image con-
tracting as the center of the jet left the star behind. A transit
of this kind has not frequently been observed, at least under such
favorable conditions as to brightness and definition of the objects,
and it is to be hoped that others may have been as fortunate as
Mr. Green and the undersigned.

If the point, which obeys the Newtonian law, be a solid body,
the observation just recorded seems to show that its true outline

164 Miscellaneous intelligence.

would probably be rendered unrecognizable, and its aspect totally
altered by the (refractive ?) power of the coma and jets. — Nature,
July 7.

3. Observation on the Cornet ; by W. H. M. Christie, made
at the Royal Observatory, Greenwich. — Further measures have
been obtained at Greenwich of the position of the least ref rangibfe
edge for three of the four comet-bands with the following results: —

Yellow band.

Green band.

Bine band.

Comet

5630-4 ±1*6

51627 ±0*4

4733-9 ±1'1

Bunsen Flame

5633-0

51640

4736*0

No. of Obs.

The identity of the comet-bands with thtfse in the first spectrum
of carbon appears to be clearly established, but in each case the
comet-band is slightly shifted toward the blue. The displace-
ment of the green band, if real, would indicate an approach of
47±14 miles. per second, whereas the comet was actually receding
from the earth at the rate of about twenty miles per second.
Such a displacement might, of course, be explained by an emission
of cometary matter on the side toward the earth, but it would
seem more probable that it is due to the circumstance that the
edge of the comet-band is not quite sharp, and that a small por-
tion on the red side is cut off. This would apply with still more
force to the yellow and blue bands, which indicate somewhat
larger displacements toward the blue. The displacements how-
ever, though all in the same direction, are not largely in excess of
the probable errors. The comet-bands were compared with those
given by vacuum-tubes containing cyanogen and marsh-gas, as
well as with those of the Bunsen-burner flame, and three forms of
spectroscope were used, viz : (1) the half-prism spectroscope with
a dispersion of 18£° from A to H, and a magnifying power of 14 ;
(2) the half-prism spectroscope reversed (as for prominence ob-
servations), giving a dispersion of 5° from A to H and great purity
of spectrum, with a magnifying power of 28 ; and (3) the star
spectroscope with a single prism of flint. No measures were ob-
tained of the band in the violet, which was only seen on two
occasions. It appeared to be sensibly coincident with the band
in the first spectrum of carbon at 4311. — Nature, July 14.

V. Miscellaneous Scientific Intelligence.

1. International Polar Stations occupied by the Signal Service.
— The head of the U. S. Signal Service, General Hazen, has issued
circulars from which are taken the following facts.

The permanent station will be established at the most suitable
point near Point Barrow, Alaska (71° 27' N., 156° 15' W., as de-
termined by Beechey). Meteorological, magnetic, tidal, pendulum
and other observations of a physical kind are to be made and also
collections gathered, as complete as possible, in mineralogy, botany,
zoology and ethnology. This station will be visited in 1882, 1883,
and 1884 by a steamer or sailing vessel, to furnish supplies and
such additions to the party as may be necessary.

Miscellaneous Intelligence 165

The officers assigned to duty as the expeditionary force are
Lieut. P. Henry Ray, of the 8th Infantry, Acting Signal Officer,
and Commander of the Expedition; G. S. Oldmixon,U. S. Army,
Acting Assistant Surgeon ; Sergeants J. Murdoch, U. S. A., and
Middlbton Smith, U. S. A., Naturalists and Observers; Capt.
E. P. Hbrendeen, Interpreter, Storekeeper, etc. ; Mr. A. C. Dark
(of the Coast Survey), Astronomer and Magnetic Observer.

The meteorological and tidal observations will be made at exact
hours of Washington civil time — the longitude of the Washington
Observatory being 5h 8m 128,09 west of Greenwich ; and the regu-
lar magnetic observations at even hours and minutes of Gottingen
mean time — Gottingen being in 0h 39m 468*24 east of Greenwich,
or 5b 4Ym 588,33 east of Washington. The equipment in instru-
ments for the various kinds of physical observations is to be very
complete.

2. Annual Report of the Board of Regents of the Smithso-
nian Institution, for the year 1879. 632 pp. 8vo. Washington,
1880. — The Smithsonian Institution is ably fulfilling its purposes
under Professor Baird, in the various ways established during the
administration of Professor Henry. This Report gives an account
of what it is doing in the way of aiding and extending research,
and explorations, making collections and sustaining the National
Museum, carrying forward the objects of the Fish Commission,
making exchanges in specimens, transporting exchanges in publi-
cations between this and foreign countries and by various other
methods. Pages 143 to 212 are occupied with a memoir on James
Smithson and his bequest. Next follows the General Appendix
containing many Archaeological and Ethnographic papers, occu-
pying 270 pages, and also, Reports of American Observatories by
Prof. E. S. Holden, and translations of a memoir by Dr. F. J. Pisko
on the present fundamental principles of Physics, and another by
E. H. Von Baumhauer, Permanent Secretary of the Netherland
Society of Sciences, Harlem, on a Universal Meteorograph designed
for detached Observatories.

3. Endowment of the American Chemical Society. — An effort
is now on foot, and vigorously pushed, to secure an endowment
for the maintenance of the American Chemical Society. The
sum proposed to be raised is fifteen thousand dollars, and a list
published in the Philadelphia Inquirer, July 6th, shows that
about one-half this sum has already been subscribed. Professor
Albert R. Leeds of Hoboken is Chairman of the Endowment
Fund Committee, and receives notices of subscriptions. This
laudable effort will, when complete, place the publication of the
Journal of the Society upon a safe basis. The chemical manufac-
turers of the United States are a wealthy body, and we notice with
pleasure that some of them have responded liberally to this call,
as indeed they can well afford to do. There are but few men of
wealth among the chemical investigators, but the names of several
of the leading chemical teachers are recorded as subscribers to
this fund ; and aid from others is invited.

166 Miscellaneous Intelligence.

4. Dr. J, Lawrence Smith's Collection of Minerals and Mete-
orites.— We learn from the correspondence published in the Louis-
ville Courier-Journal of July 12th, that Dr. Smith has presented his
minerals and meteorites to the u Polytechnic Society " of Louisville,
Kentucky. This society already possessed the well known miner-
alogical collection formed by the late Dr. Troost of Nashville
University. The collection of meteorites formed by Dr. Troost,
and for the most part described by him, was separately secured
by Dr. Smith, and he had added largely to it by his own
researches and exchanges. The collection thus increased now
returns, as we understand, to the Troost cabinet.

Dr. Smith's gift to the " Polytechnic " includes also a collection
of physical apparatus, which will now be in the custody of Dr.
Tobin, who is entirely devoted to its preservation and scientific
usefulness.

OBITUARY.

Achilla Delesse. — The death of Delesse is mentioned on page
416 of the May number of this Journal. Delesse's researches in
science were chiefly in the departments of mineralogy and geology.
His labored memoirs on metamorphisra and pseudomorphism, and
his investigations with regard .to the chemical constitution and
other characters of various kinds of rocks, contributed largely to the
progress of lithology and geology. He experimented also with
important results on the expansion of rocks by heat and fusion, the
magnetic properties of rocks, their absorption of moisture and its
effects on their resistance to crushing, and on other points. In con-
nection with the results of the Exposition at Paris of 1855, he pro-
duced a very valuable work entitled "Mat&riaux de Construction;"
and he later published memoirs illustrated by large charts, on the
constitution of the bottom of the seas, and on the soils, under-
ground water-plain, and subsoils, about Paris. His " Revue des
Progres de la Ge'ologie," prepared for the " Annales des Mines,"
but lately with the aid of M. de Lapparent, reached its sixteenth
volume during the past year. Delesse, in 1845, was placed in
the chair of Mineralogy and Geology at Besanc,on, and in 1850,
in that of Geology, at the Sorbonne, at which time he was made
"Ingenieur des Mines," and had charge of the quarries of Paris.
Eighteen years later he was made Professor of Agriculture at the
ficole des Mines. In 1878, he was promoted to Inspector-General
of Mines, and placed in charge of the southeast division of France.
Delesse was elected a member of the Academy of Sciences in 1879.
M. Daubree closes as follows his remarks at the funeral, on the
29th of March : " The breadth of mind and uprightness of Delesse,
his astonishing powers of work, his learning, his kindness of heart,
associated with true modesty and great loyalty of character, have
made him esteemed and beloved during all periods of his useful
career."

Etien^e Henry Sainte Claire Deville, the eminent French
Chemist, died at Boulogne-sur-Seine, on the 1st of July, having
passed his 63d birthday in March last.

THE

AMERICAN JOURNAL OF SCIENCE.

[THIRD SERIES.]

♦ ♦♦

Art. XXIX. — Benjamin Peirce.*

Benjamin Peirce was born in Salem, Mass., on the 4th day
of April. 1809, and he died at Cambridge, on the 6th day of
October, 1880.

In his early years he had the good fortune to come under the
influence of Doctor Nathaniel Bowditch. It is said that their
first acquaintance was made while Dr. Bowditch 's son Ingersoll
and young Peirce were schoolmates. Ingersoll showed his
comrade a solution which his father had prepared of a problem
that the boys had been at work upon. Some error, real or con-
ceived, was pointed out in the work, which was reported by
Ingersoll to his father. "Bring me that boy who corrects my
mathematics 1" was the invitation to an acquaintance, the im-
portance of which in Professor Peirce's own estimation is told
in the dedication, more than thirty years later, of his " Analytic
Mechanics " " to the cherished and revered memory of my
Master in Science, Nathaniel Bowditch, the father of American
Geometry."

Peirce entered Harvard College in 1825. As Doctor Bow-
ditch was now in Boston, having removed from Salem in 1823,
and was preparing the first volume of his translation of La-
place's u Mecanique C&este" for the press, it followed almost as
a matter of course that the college student was more influenced
in his studies by him than by the college course. Doctor Bow-
ditch's first volume was completed and the second entered for

* The Journal is indebted for this memoir to advance sheets from the Proceed-
ings of the American Academy of Arts and Sciences, Boston.

Am. Jour. Sol— Third Srribs, Vol. XXII, No. 129.— September, 1881.
12

168 Benjamin Peirce.

After graduation, two years were spent by Professor Peirce
in teaching at Northampton. In 1831 he was appointed Tutor
in Harvard College, and in 1833 was made Professor of Mathe-
matics and Natural Philosophy.

The earlier years of his professorship were fruitful as to pub-
lication, principally in a series of text-books for use in college.
The first that appeared were treatises on "Plane and Spherical
Trigonometry v in 1835 and 1836, which were published in a
more complete form, with a " Spherical Astronomy," in 1840.
Next came a " Treatise on Sound," in 1836, which was based
upon Herschel's work in the " Encyclopaedia Metropolitana,"
but with very important changes. The bibliography of the
subject in the Introduction is of permanent value. This was
followed, in 1837, by his "Plane and Solid Geometry," and by
a " Treatise on Algebra."

A work on " Curves, Functions and Forces " was begun in
1841 by the publication of a volume on "Analytical Geometry
and Differential Calculus," A second volume, on the " Calcu-
lus of Imaginaries, Eesidual Calculus, and Integral Calculus,"
appeared in 1846. As the word "forces" in the title shows,
he intended to complete this work by a third volume on the
" Calculus of Variations, and on Analytical Mechanics, with its
Applications," but in this form it was never done.

Instead of this, however, and so to be mentioned in this
place, though not properly a text-book, there appeared in 1855
the " Analytic Mechanics " in a quarto form, a work that more
adequately expresses Professor Peirce's peculiar power than any
other of his productions, with perhaps one exception.

In all of these books he departed not a little from the beaten
path. In geometry the idea of direction was made the basis of
the theory of parallels. Infinites and infinitesimals are intro-
duced, along with the axiom, "Infinitely small quantities may
be neglected." The demonstrations are given only in outline,
being in respect of fulness the entire opposite o Euclid. A
like brevity is characteristic of the other books, and in fact of
everything mathematical that Professor Peirce ever wrote. He
used a notation to which he gave much thought, by which his.
formulas were more concise than they could easily be made
with the usual symbols. The Integral Calculus was at the
period of its appearance much in advance of similar works,
especially in the treatment of differential equations. It is an
excellent example of Professor Peirce's concise and logical style.

The "Analytic Mechanics " was rather a treatise than a text-
book. In it Professor Peirce set forth the general principles
and methods of the science as a branch of mathematical theory,

Benjamin Peirce. 169

and embodied in a systematic treatise the latest and best meth-
ods and forms of conceptions of the great geometers. He aimed
to reduce them to their utmost simplicity by freeing them from
every superfluous element. He made free use of the idea of
the potential, developing nearly the whole subject from it. De-
terminants are used regularly as a standing instrument of
analysis, and especially in the integration of the differential
equations of motion. Both of these features, as well as Jacobi's
method of integration, by his principle of the last multiplier,
were at the time new in English treatises.

The whole volume is marked by a directness of thought and
a brevity of expression which make it difficult reading for those
who have been accustomed only to the usual forms of notation
and reasoning, and who do not read the book in course from m
the beginning. Several of the chapters are made peculiarly
interesting by the development of a large number of special
problems as particular cases of general theorems. In his later
years the author often said he wanted to rewrite the u Analytic
Mechanics " and introduce quarternions into it.

In 1842 Professor Peirce published, in connection with Pro-
fessor Lovering, four numbers of the "Cambridge Miscellany,"
a quarterly journal devoted to mathematics, physics and as-
tronomy.

In the same year he assumed the care of the mathematical
part of the " American Almanac,'' ten volumes of which were
prepared by him. In one of these (1847) he published a list of
the known orbits of comets, arranged in convenient form, to
which he added to the usual cometic catalogue several approxi-
mate orbits computed by him for historic comets that had been
imperfectly observed.

In 1849 Congress established a Bureau for the publication of
the "American Ephemeris and Nautical Almanac," under the
superintendence of Lieutenant (afterwards Admiral) Davis.
Professor Peirce was at once appointed Consulting Astronomer.
In this capacity he prepared and published, in 1853, his u Ta-
bles of'the Moon," which have been used in making the "Ephe-
meris " up to the volume for the year 1883. In cooperation
with Lieutenant Davis, he designed the form and general plan
of the Ephemeris, and he decided upon all the coefficients to be
used. He commenced a revision of the theory of the planets,
especially the four outer ones ; but this seems not to have been
carried to serviceable results, if we except certain separate com-
munications to this Academy. He retained the position of Con-
sulting Astronomer until 1867. The high place which the
" American Ephemeris " has ever held among like publications
owes much to the character given to it by Professor Peirce in
these its earliest years.

170 Benjamin Peirce.

When, in 1846, Galle discovered the planet Neptune in the
place pointed out to him by Leverrier, Professor Peirce took
the liveliest interest in the admirable researches of Leverrier
and Adams. He entered with zest into all the questions which
were thus raised. What is the orbit of the new planet? What
its mass ? How much do they differ from the assigned orbits
and masses ? Does the new planet explain all the irregularities
of Uranus? Did the data lead necessarily to the assigned
place, and to it alone ?

The results of his investigations were at various times given
to this Academy, but more especially on the 4th of April, 1848.
He then gave the perturbations of longitude and radius vector
of Uranus by Neptune, and announced that Neptune and either
of the two hypothetical planets of Leverrier and Adams would
equally explain the observations of Uranus, within reasonable
limits of error.

Leverrier had proposed to himself to solve the following prob-
lem : — From the observed irregularities of the planet Uranus to
compute the elements of the orbit of an assumed exterior planet
that has caused these irregularities. He ought perhaps to have
limited himself to the other problem, to which he gave so cor-
rect an answer, Where among the stars astronomers must look
in order to see the disturbing body. The elements of the orbit
could be had from observations when once the planet was seen.
He found for the unknown planet an orbit and a mass by pro-
cesses that will always command the admiration of men ; and
the place. in that orbit, as is well known, was less than one de-
gree, as seen from the earth, from the actual place where Galle
found Neptune.

Yet Professor Peirce declared that Leverrier's geometric planet
and Neptune were not the same bodies. He praised without
question the work of Leverrier and of Adams, asserting for them
their right to all the praise and eclat which the world had given
them. But Leverrier had distinctly stated that the planet
which disturbed Uranus could not be at a less mean distance
from the sun than 35 ; that is, that no planet that was* within
this distance could cause the observed irregularities of the mo-
tion of Uranus. Neptune, however, is at a distance of only 30,
and does account for the perturbations of Uranus.

In this and in other communications Professor Peirce claimed
that the perturbations changed their character at the points
where the mean motions had the ratios 2 : 5 and 1 : 2, and that
the reasonings of Leverrier were thereby vitiated. Not a little
controversy has come from these papers of Professor Peirce;
and we cannot say that the last word in regard to the question
has even yet been spoken. As is not unusual in like discus-
sions, there is probably a portion of truth and a portion of error

Benjamin Peirce. 171

with either party. Leverrier and Adams each, as Professor
Peirce has himself shown, by his own laborious researches, did
point out correctly a place where a planet should be looked for,
and assigned paths which that planet could have been traveling
for more than one hundred and twenty years previously, and
have caused the observed irregularities. Yet the elements of
that planet's orbit and its mass and those of Neptune differ
widely enough to justify the assertion that for the latter they
were not correctly given.

On the other hand, astronomers will not probably agree with
Professor Peirce in regarding the change of character of the per-
turbations when the mean motions of the new planet and of
Uranus pass through the exact ratios 2 : 5 and 1 : 2 as of vital
importance. In the usual form of development these fractions
do indeed make certain terms infinite. That belongs, however,
to the form of the development, not to the perturbations. In
solving the question, "Where is the disturbing body?" the
solution need not have involved these forms; and it has not
been shown that they entered into the work of either Leverrier
or Adams in such a way as to vitiate it

That the problem was really indeterminate has been steadily
held by Professor Peirce. In January, 1878, he read to this
Academy a paper, which has not been published, and the con-
clusions of which, therefore, will not compel the assent of as-
tronomers until some one else shall have gone over the same
questions. He showed a chart of the plane of the ecliptic with
the orbits of Uranus and Neptune, and having those parts of
the plane shaded within any part of which a planet of arbitrary
mass might have been situated in September, 1846, and yet
have caused, in the preceding years, the observed irregularities
in the motions of Uranus, within reasonable limits of error.
With a circular orbit, a large fraction (more than one half) of
the ecliptic, as seen from the earth, contained some of the
shaded portions. If an eccentricity not greater than one-tenth
be allowed, the region was greatly enlarged. While, therefore,
the solutions of Leverrier and Adams gave a place and a path
that explained the disturbances, the problem in its nature was
not, he claimed, one having a single answer, or even a finite
number of answers.

In 1852, Professor Bache, then Superintendent of the United
States Coast Survey, induced Professor Peirce to take up the
subject of the longitude determinations in the Survey. As a
result, there appeared in the successive volumes of the " Coast
Survey Reports," communications from him upon the several
questions that arise in the treatment of that subject. The most
noteworthy referred to the determination of our longitude from
Greenwich, since local differences were determined by the tele-

172 Benjamin Peirce.

graphic method. The whole subject of errors of observations,
the law of facility of error which is assumed in the method of
least squares, its limits and defects, and the habits of observers,
were carefully examined. The method of occultations was de-
cided to admit of greater accuracy than any other that was then
available, and the occultations of the Pleiades to fiirnish the
most convenient means of its application. Formulae and tables
were prepared, old observations collected, and new ones made
to apply this method. The question of our longitude is now,
thanks to the ocean telegraph, one of history ; but the ques-
tions of errors in observing, which Professor Peirce so thor-
oughly treated, will always be of practical import.

It seems as though there was a connection between this en-
gagement with the Coast Survey and the appearance, in July,
1852, in Gould's " Astronomical Journal," of an article by Pro-
fessor Peirce, entitled, " Criterion for the Eejection of Doubtful
Observations." His object was to solve this problem : There
being given certain observations, of which the greater part is to
be regarded as normal, and subject to the ordinary law of error
adopted in the method of least squares, while a smaller un-
known portion is abnormal, and subject to some obscure source
of error, to ascertain the most probable hypothesis as to the
partition of, the observations into normal and abnormal. This
method or rule given for deciding whether an observation had
better be left out of account has received the name, "Peirce's
Criterion," and must be regarded as one of his best contribu-
tions to science. Tables for use in applying it were soon after-
ward published by Dr. Gould.

The " Criterion" has been criticised by Professor (now Sir G.
B.) Airy as defective in its foundation and illusory in its re-
sults ; and he was even of opinion that no rule for the exclu-
sion of an observation can be obtained by any process founded
purely upon a consideration of the discordance of those obser-
vations. This position of the Astronomer Royal must be re-
garded as entirely untenable; for no observer hesitates to call a
widely discordant observation a mistake, and to reject it (when
he can find no other reason for so doing), simply because of
that discordance. What the mind thus instinctively does, there
must be basis at least for a rule for doing. Professor Airy's
objections were answered by Professor Winlock at the time of
their appearance. The " Criterion" has been used considerably
in this country, though not, perhaps, in Europe. The uniform
testimony of our computers is, we believe, that it has given ex-
cellent discrimination, and that it does not come into conflict
with proper judgment based upon experience. This shows the
good working of it in actual practice.

That the " Criterion" has not come into use in Europe may

Benjamin Peirce. 173

in some degree have been due to the excessive brevity of the
argument by which Professor Peirce established the equations
to be used. Perhaps no one has read that argument for the
first time without finding difficulty in understanding some parts
of the reasoning. A want of confidence may thus have easily
resulted. Professor Chauvenet has given us a simpler rule for
use in rejecting a single divergent observation; but it is only
an approximate solution, since one important element is left
out of account. Computers need some such rule to guide them,
and it would seem almost certain that "Peirce's Criterion," or
possibly some modified form of it, will in time secure general
acceptance. In any case, it will ever stand as the first, and as
a satisfactory, solution of this delicate and practically important
problem of probability. At present it is the only solution we
believe that claims to be complete.

After the death of Professor Bache, Professor Peirce was, in
1867, made Superintendent of the United States Coast Survey,
and he discharged the duties of that office for the next seven
years. Soon after his appointment he made a tour of inspection
among the parties at work in the field. Notwithstanding his
previous intimate relations with the survey as adviser to Profes-
sor Bache, he was very much surprised and delighted with the
practical skill which many of the officers had acquired. "I
recognize at once," he said, athe masters of the profession."
Unfortunately, he recognized also the awkward and inefficient,
and the presence of these, which even the admirable executive
abilities of his predecessor had not been able to eliminate, gave
him great concern. Yet he determined to hold to the broad-
est line of policy, and introduce no rigid discipline that might
damp the ardor and spontaneity of the faithful. " The lame
and the lazy are always provided for," says the adage; and in
the public service they are found, practically, to have the most
friends from without, because needing them most. In a scien-
tific service like the Coast Survey, which, unlike many of the
departments of the civil service, furnishes absolute criteria from
which to judge the merits of an officer, the task of discrimina-
tion, if undertaken by a superintendent well versed in the math-
ematics and physics underlying the manoeuvres of the surveyor,
would seem to be as easy as it is just. But it was a saying of
Professor Bache, that " it would be easy enough to crush directly
the men who betrayed the good repute of the service if it was
not for uncles, aunts, and cousins, who proposed, in their turn,
to crush him."

It was after his return from one of his earliest tours of in-
spection that Professor Peirce, in conversation with one of the
older assistants, said he proposed to give, at least at the outset,
greater freedom of action to the officers of the corps, that each

174 Benjamin Peirce,

might indicate the full scope of his powers and receive promo-
tion, or give place to another according as the results of his
work might determine. " The office," he said, " can add noth-
ing to my reputation unless I can give it greater dignity by
raising the standard of the service. I mean to bring the best
men to the front and secure publicity to their merits, that they
may feel directly responsible to the community and do their ut-
most for its approbation. To become the leader of a corps of
distinguished men is the best thing I can do for the country, for
the men themselves, and for my own reputation." This was
the policy which he initiated in the Coast Survey, and its wis-
dom was demonstrated at once. A very large proportion of
the officers appreciated his motives, caught the enthusiasm of
his genius, and found a new delight in serving a master who
coveted nothing, but with rare simplicity lent his own strength
to secure to them the full rewards of their labors.

The most important work started by Professor Peirce, and
much advanced under his direction, was the actual extension of
geodetic work into the interior of the country by continuing the
great diagonal arc from the vicinity of Washington to the
southward and westward along the Blue Eidge, eventually to
reach the Gulf of Mexico near Mobile. He also planned the
important work, now in active progress, for measuring the arc
of the parallel of thirty-nine degrees, to join the Atlantic and
Pacific systems of triangulation, and for determining geograph-
ical positions in States having geological or topographical sur-
veys in progress.

He conferred a very important benefit on public interests by
so enlarging the scope of the Survey as practically to extend
geodetic work into the interior States.

As soon after the war as vessels and officers could be had, he
renewed operations for deep-sea soundings and dredgings, and
he gave earnest support and aid to all scientific work in any
way related to the Survey.

While Superintendent he also took personal charge of the
American expedition to Sicily, to observe the eclipse of the sun
in December, 1870.

By virtue of his office he was a member of the Transit of
Venus Commission, and by his suggestions and active effort he
greatly aided that undertaking. Two parties from the Coast
Survey were sent out by him, — one to Nagasaki, and the other
to Chatham Island, to take part in the work.

The " Quaternion Analysis " of Hamilton seemed to Professor
Peirce to promise a very fruitful future. " I wish I was young
again," he said, " that I might get such power in using it as only
a young man can get. " He took great pains to interest his stu-
dents in it, and in his later years formed a class for its earnest

Benjamin Peirce. 175

practical study, with good results. His own thought was
turned especially to the logic that underlies all similar systems,
aud to the limits and the extensions of fundamental processes
in mathematics.

At the first session of the National Academy of Sciences, in
1864, he read a paper on the elements of the mathematical the-
ory of quality. Between 1866 and 1870 various papers were
read to that Academy, or to this Academy, on " Linear Alge-
bra," "Algebras," "Limitations and Conditions of Associated
Linear Algebras," "Quadruple Linear Associative Algebra,"
etc. These papers were not printed in form as read, but instead
in 1870-71 appeared his "Linear Associative Algebra."

His own feeling about this contribution to science is ex-
pressed in the salutatory to his friends: "This work has been
the pleasantest mathematical effort of my life. In no other
have I seemed to myself to have received so full a reward for
my mental labor in the novelty and breadth of the results."

An analysis of this treatise was given by Doctor Spottis-
woode to the London Mathematical Society, which is character-
ized by Professor Peirce as " fine, generous and complete."
Such an analysis can only come from one who has made a
special study of the laws of mathematical thought To some
mathematicians, and other men of science, it may yet be a
question, if the time has come for them to say with entire
certainty whether this work is to share the fate of Plato's
barren speculations about numbers, or to become the solid
basis of a wide extension of the laws of our thinking. Those
who have thought most on the course which contemporary
mathematical science is taking will probably agree that the new
ground thus broken can hardly fail to bring forth precious
fruit in the future by adding to the powers of mathematics as
an instrument.

In any case, the Associative Algebra can never lose its value
as an important and most beautiful addition to Ideal Mathemat-
ics, and must ever remain a monument to the comprehensive
grasp of thought and analytical genius of its author.

Professor Peirce defines mathematics as the science which
draws necessary conclusions. Algebra is formal mathematics.
Addition is taken to express a mixture, or mere union of ele-
ments, independently of any mutual action which might arise if
they were to be mixed in reality. From this definition, the
commutative character of addition necessarily follows. Mul-
tiplication is no further defined than as an operation dis-
tributive with reference to addition ; but the only algebras
treated are those whose multiplication is associative. The
subject is further limited to linear algebras, that is, to such as
contain only a finite number of lineally independent expres-

176 Benjamin Peirce.

sions ; so that every quantity considered may be put under the
form,

ai -f- bj -f- ck -\- etc.

where i,j\ Jc, are peculiar units, limited in number; while a, 6.
c, are scalars, — a term borrowed from the language of quaterni-
ons, but here used in a modified sense to include, not merely
the reals, but also the imagiuaries, of ordinary algebra. A
variety of highly general theorems are given, extending to all
linear associative algebra?. The author next introduces the
conception of a pure algebra, as contradistinguished from one
which is virtually equivalent to a combination of several.
Methods are developed for finding all such pure algebras of any
order. Finally, he obtains the complete series of multiplication
tables of these algebras up to the fifth order, together with the
most important class of the sixth order. They are in number
as follows :

Single Algebras , 2

Double " 3

Triple " 5

Quadruple " - 18

Quintuple u 70

Sextuple •' 65

Professor Peirce never made any extended study of the possi-
ble applications of his algebras; he was far from thinking,
however, that their utility was dependent upon finding inter-
pretations for them; on the contrary, he showed that certain of
them could be advantageously employed, without any interpre-
tation, in the treatment of partial differential equations like
that of Laplace.

He read to this Academy in May, 1875, a memoir u On the
Uses and Transformation of Linear Algebra," which is, we be-
lieve, his only published addition to the principal treatise. He
had also made some progress in the investigation of the laws of
non -associative algebras.

Professor Peirce could not fail to be interested in all ques-
tions that concern the equilibrium, the history, and the devel-
opment of the solar system. At first he was loth to accept the
nebular hypothesis in any form. But the results of his studies
led him, at last, to defend its main propositions as the true laws
of creation.

The rings of Saturn are of prime import in any explanation
of planetary development. The discovery by Professor Bond,
in 1850, of the dusky ring, and his announcement of reasons
for believing that the rings were fluid, multiple, and variable in
number, led Professor Peirce to take up the mathematical the-
ory of the rings. He announced, as the result of his analysis,
that the rings could not be solid, that a fluid ring could not

Benjamin Peirce. 177

have its centre of gravity controlled by its primary, and that it
must be supported by the satellites. The principles of the solu-
tion were indicated in an article, published in " Gould's Astro-
nomical Journal " in 1851. At different times in the following
years some portions of his theoretical treatment of the problem
were published. The mathematical possibility of a large num-
ber of narrow solid rings was admitted. In the " Memoirs of
the National Academy of Sciences" he published, in 1866, the
formulas for the potentials and attractions of a ring. This
problem has peculiar interest, from the mode of development of
the formulas.

The place of comets in the solar system was a subject of
his thought even earlier than the rings of Saturn. The dis-
cussions and the computation of orbits of various comets in the
years 1846-1849, were followed in the latter year by an argu-
ment that the comets must have always been parts of the solar
system.

In 1859 he applied the theory of solar repulsion of the mat-
ter of the comets' tails to the observed form of the tail of
Donati's comet, and deduced the strength of the repulsive
forces that drove off the nebulous matter. The next v ear he
gave, in a letter to the Academy of Sciences, of Paris, twelve
remarkable and suggestive theses on the physical constitution
of comets.

In 1861 he made a communication to this Academy, suggest-
ing the meteors as a cause of the acceleration of the moon's mean
motion. The paper was not printed, and it does not appear
whether he referred to the direct impact of the meteors upon
the moon, or to the resistance due to the action of the moon in
turning the meteors out of their paths. Probably he included
both causes, since each has the effect, to a limited degree, of a
resisting medium.

In the last two years of his life he presented to this Academy
several communications upon the internal structure of the earth,
and the meteoric constitution of the universe. Especially in
October, 1879, he gave a series of eight propositions in Cos-
mical Physics. At an informal scientific meeting at Harvard
University he stated five others, which have been since
printed in the Appendix to his "Lectures on Ideality in Sci-
ence." They were given rather as a basis for criticism and dis-
cussion than as fully proved. They are founded upon the the-
ory of Mayer, which is advocated by Sir William Thomson, that
solar heat, and in part planetary heat, are supplied by the collis-
ion of meteors with the sun and planets. Small portions of
matter in space cool and become invisible solid meteors. These,
by their impact with the sun, produce the violent commotions
of the sun's surface. A portion of the earth's beat comes from

17& Benjamin Peirce.

the sun, another portion directly from the impact of meteors
with the earth's atmosphere. The two portions, he afterwards
shows, are equal.

These views are developed more fully in his "Lectures," re-
cently published. The meteors, as Professor Peirce believed,
come from the outer portions of the condensing solar nebula.
In the course of development an outer shell was left, which fur-
nished the matter to be collected in small masses. The small-
est become meteors, the larger comets. Their numbers are
enormously great. Arranged according to perihelion distances,
the number of comets or meteors coming within a given distance
of the sun varies directly as the distance. The heat of Jupiter
and Saturn comes from the collisions with those planets. The
interior of the earth may be liquid throughout, and the limits set
to the lengths of the geologic ages may reasonably be greatly
extended.

Any attempt to outline the history of the solar system is
sure to lead, in the present state of knowledge, into serious
difficulties. Necessarily the problems that arise do not, in
many cases, admit of quantitative analysis. The number of
unknown elements that appear with every new hypothesis
is large; and the more we learn, the larger the number of
questions which we cannot answer. It will be but natural if
some of the theses of Professor Peirce shall be questioned, and
even be proved unsound; but scholars who shall be led into this
fascinating field of study will always find in them profound and
most suggestive views of creation. Some of these theses will
undoubtedly be found to be the true and previously unknown
laws of nature.

Professor Peirce was always warmly interested in everything
that promoted science in this country. He was generous in his
estimate of merit, especially of merit in young men. He was
one of the founders of the National Academy of Sciences,
was an early President of the American Association for the
Advancement of Science, was one of the most active mem-
bers of this Academy, and was a frequent recipient of academic
honors. American science mourns in his death the loss it
cannot express, but has a higher life for his having lived.

H. A. N.

K S. Dana — Spodumene from NorUi Carolina.

Art. XXX. — On the Emerald-green Spodumene from Alexander
County, North Carolina ; by Edward S. Dana.

The composition and method of occurrence of the beautiful
emerald-green spodumene from Alexander County, North Caro-
lina, was described by Dr. J. Lawrence Smith in a recent num-
ber of this Journal ;* —the variety was called by him biddenite
after Mr. W. E. Hidden. Dr. Smith's article included a few
notes by the writer in regard to the crystalline form of the
mineral. The material available for study at that time was
scanty and not suited for any accurate determinations of the
form. Since then Mr. Hidden has had the kindness to place
in my hands a considerable number of crystals, some of them
showing the terminations with tolerable distinctness.

The crystals have uniformly a prismatic form, and vary
from half an inch to two or three inches in length. They are
usually very slender, though sometimes attaining a thickness
'of one-third to one-half an inch in the direction of the clino-
diagonal axis ; in the other transverse direction they are much
thinner. The crystals show a considerable variety in habit as

will be inferred from the annexed figures, f Figures 1 and 2
represent the same form but the position of the axes is changed :
in fig. 1 the clinodiagonal axis d is, as usual, inclined to the
front, while in fig. 2 and in the other figures this axis is in-
clined to the left side, and the orthodiagonal axis b projects to
the front The following figures, 5, 6, 7, 8, 9, are from sketches
by Mr. Hidden.

The prismatic planes are uniformly striated vertically, and
the crystals are not unfrequently rounded by the oscillatory

□ capitals instead

* Vol. ni, p. 128, Feb., 1881.

\ The enajaver, 07 mistake, bas put the lettering of the ci
jf email letters.

180

S. S. Dana^Spodumene from North Carolina.

combination of the occurring planes in this zone; in addition
these planes, more especially those of the fundamental prism /,
are usually pitted with little depressions which will be more
particularly mentioned later. The crystals are often flattened

parallel to the clinodiagonal axis but nearly square forms show-
ing only the prism I are occasionally observed. The terminal
planes, when they may be said to exist at all, for the crystals
are usually terminated very irregularly, are always rough, or
striated. The only one of the terminal planes which is at all
constant in occurrence is the hemi-pyramid r (221). The
planes g (681), e (241), u (243), p_ (til) form au oblique zone, as
shown in figures 1 and 2, and in the majority of the crystals
the presence of the same zone is manifest, although no distinct
planes are to be determined, the planes rounding uninterrupt-
edly into each other and continuing the front edge (//-/) over
the top of the crystals. This feature is shown in fig. 4 and
also in figs. 5, 6, 7 which represent twin crystals.

The twin crystals are common, probably more so than the
simple crystals. The plane a (100) is uniformly the twinning
plane and the twinning-axis is normal to it ; it is also the com-
position plane. The twin crystals are usually nearly symmet-
rical in form (see figs. 5, 6, 7), and the two halves are united in
a sharp well-defined line, as proved by an examination with the
polariscope. In the case of crystals not terminated, or with
terminations too rough to show whether or not they are twins,
the composite character is proved by the little depressions on
the planes of the prism I, since they are inclined in the same
direction both in front and behind (figs. 5 to 9).

The observed planes are as follows : —

E. & Dana — Spodumene from North Carolina. 181

100

• •

010

001

320

i.}

110

120

i-i

130

i-3

441

221

332

Til

261

681

241

243

241

231

561

1
-6-3

-4-2
i-2
4-2

3-|
6-t

Of the above planes b} s, g, z, g, e, u, e, x, y, are new to the
species.

Unfortunately, the crystals, while uniformly perfectly trans-
parent, do not in any case allow of even tolerable measure-
ments, so that no more exact values of the fundamental angles
could be obtained than those measured by Professor J. D.
Dana with the hand goniometer on the large crystals from
Norwich, Mass. On this account these angles are accepted as
the basis of calculation, viz :

c~a 001 /s 100=69° 40'
1^1 110^110=93°

c*e 001^021=50°

The corresponding values of the axes are : —

c (vert.)=0-565 6=0-890 <2=1000

Some of the more important angles (supplement angles) for
the occurring planes, calculated from the above axes, are as
follows : —

b (010)^7 (110)=43e

~l (320)=54

*m (120)=25

*n (130)=17

(681)=37

(241)=36

(261)=26

(441)=41

(221)=45

(332)=49

(Ul)=58

(231)=34

(241)=27

((

"9
/s e

aZ
*8

~P
~x

^ e

30'
55
23
33

3
18

5
48
43
57
15
21

b (010) ^ u

~ e

a.U

_ *P
l(\\0)~s

q
p

€

((

243)=40°

16'

f>61)=53

681)=10

241)=21

243) =63

111)=75

441)=]7

221)= 34

332)=44

Tll)=59

561)=14

(231)=32

[241)=32

As has been stated the measured angles are only rough ap-
proximations, they serve however to determine the several
planes. As far as needed for this end, in conjunction with the
obvious zonal relations, they are as follows: —

Z(ll0)^« (441)=18°

r (221)3:35

q (332)=45

p (111)=60

y (561)=14^15<

x (231)=32

7(110)

b (010)

*9
e

u
P

(681)=10°
(241)= 22
(243)= 62
(Ill)=75
(241)= 27
(231)=34-34° 30'
(221)=45-46°

182 JS. S. Dana — Spodumene from North Carolina.

The little depressions observed on the planes in the pris-
matic zone are an interesting feature of the crystals ; those
which occur on the planes / are the most marked. They ap-
pear on the cleavage as well as the natural planes, and often in
such numbers as to completely cover the whole surface. Their
outline is wedge-shaped and on the front planes (fig. 1) they
are inclined upward toward the edge // /, and similarly down-
ward toward the edge behind in the simple crystals. The
form of these depressions is more exactly shown in fig. 10,
representing two in symmetrical position and much
enlarged. The lower surface is formed by the plane
/, and the sides by the planes a, /3, y. Of these
planes y is apparently identical with g (681), al-
though, as indicated, it is irregular in its intersection
with the prismatic plane being curved ; a is a plane
in the prismatic zone, with a a 2=5°, corresponding \sI/\
to the plane i-\ or (650) for which the required \
angle is 5° 13'. The third plane /3 is in the zone 10*

I* 9i r> Pi eta, or that of the unit pyramids. The measured
angle of jis\I is 4°— 4° 30' and this corresponds to the plane
I6*l6*l (required I6*16*1aI=4°18'). The plane a is sometimes
rounded so as to give an oblique intersection witfi I. The
depressions on the plane b are also common though less con-
spicuous than those just named. They are rhomboidal in shape
and the outlines are respectively parallel to the prismatic edge,
and to the edge b/r.

An examination of a section in the polariscope showed that
the bisectrices lie in the plane of symmetry, and that the acute
bisectrix (positive) is inclined to the front (fig. 1) edge of
///at an angle of 26°. These determinations agree exactly
with the results given by DesCloizeaux (Mineralogy, p. 351,
1862). A suitable section for measuring the optic axes has
not as yet been obtained, one which promised to be satisfactory
went to pieces in the hands of the lapidary owing to the highly
perfect cleavage parallel to the prism /.

It is a matter of some mineralogical interest to note that this
variety of spodumene has already found a place among the
highly valued gems. The color of the finest crystals is a deep
emerald green, and when suitably cut the stones are very
beautiful ; owing to the dichroism there is a peculiar fire to
them which is wanting in the true emerald. The largest
stone cut thus far weighs very nearly 2£ carats. Explorations
are now being carried on at the locality urfder the direction of
Mr. Hidden.

IS. W. Hilgard — Objects and Interpretation of Soil Analyses. 183

Art. XXXL — Tlie Objects and Interpretation of Soil Analyses ;
by E. W. Hilgard, Professor of Agriculture at the Uni-
versity of California.

The claim of soil analysis to practical utility has always
been rested on the general supposition that, " ot/ier things being
equal, — productiveness is, or should be, sensibly proportional to the
amount of available plant food within reach of the roots during the
period of the plants' development;" provided, of course, that such
supply does not exceed the maximum of that which the plant
can utilize, when the surplus simply remains inert

The above statement has been, either tacitly or expressly,
admitted as a maxim by those who have attempted to inter-
pret soil analyses at all ; it being thoroughly in accordance
with the accumulated experience of agriculturists, and with
their cry for " enough manure" that has been so potent a factor
in the development of agricultural science, and of rational
agriculture itself. Its acceptance is implied in the search for
the solvent that shall represent correctly the action of the plant
itself on the soil ingredients ; and I shall take it for granted in
this discussion, while strongly emphasizing the proviso, espe-
cially with reference to physical conditions.

Methods of Soil investigation. — It is universally admitted that
the ultimate analvsis of soils affords little or no clew to their
agricultural value ; such agents as fluohydric acid and alkaline
carbonates go by far deeper than the solvents, naturally acting
in soils bearing vegetation, will go within the limits of time in
which we are interested.

Many attempts have been made to find solvents whose action
on soils would so nearly represent the agents subservient to
the needs of vegetation, that conclusions as to the present
agricultural value of a given soil could be deduced therefrom.
It is needless to recite the long list of such solvents, suggested
since soil analysis attracted attention. Prom fluohydric acid
to water charged with carbonic acid, the acid solvents have all
signally failed to secure even an approximation to the result
desired, viz: a consistent agreement between the quantitative
determinations, or the percentages of plant food, found in the
several soils, and the actual experience of those who cultivate
them.

It has been attempted by the German experiment stations,
under Wolff's initiative, to gain an approximation to the rela-
tive availability of parts of the soils' store of plant food, by
consecutive extractions with acid solvents of different strength,
beginning with distilled water and ending with boiling oil of

Am. Jour. Sci.— Third Series, Vol. XXII, No. 129.— September, 1881.
13

184 E. W. Hilgard — Objects and Interpretation of Soil Analyses.

vitriol or fluohydric acid. I cannot wonder that this laborious
process, with solvents arbitrarily chosen, and without any
known relation to the solvent action exerted by roots, should
have found so little acceptance, and has on the contrary per-
haps rather served to confirm the common impression of the
uselessness of soil analysis ; especially when contrasted with
such a huge amount of work, ending after all in mere guesses.
I have vainly sought, in the recorded results of such investi-
gations, for any such ray of light on the functions of the sev-
eral soil ingredients, as would even remotely justify the labor
involved.

Causes of failure. — I think there have been two chief factors
that have contributed to bringing soil analysis into disrepute
in Europe ; one is, the fact that virgin soils are there practi-
cally non-existent, nearly all the soils analyzed having been at
some time subjected to cultivation and concurrently, to the use
of manures, thus veiling their original characteristics, and ren-
dering extremely difficult, to say the least, the taking of any
sample of soil that shall correctly represent the whole of a
large field or district. The second is. the absence of syste-
matic investigation of the subject, since the time of the intro-
duction of the most essential improvements in the determina-
tion of some of the chiefly important mineral soil ingredients.

Advantages and need of Soil investigation in the United States.
— It is our special and exceptional privilege, that we are still
able to secure specimens of the soils of by far the^ greater por-
tion of the United States, that even the plow has never yet
touched, and where manure, outside of the flower and vegeta-
ble garden, is an unknown quantity. We can find on these
soils their original vegetation, which is so largely used by the
settler as a means of diagnosing the actual productiveness of
the land he proposes to clear, and of prognosing its durability.
The value of this method is so emphatically recognized as to
have given rise to the remark, by a distinguished member of
this body, that he u would rather trust an old farmer to tell
him about the value of a soil, than the best chemist alive."

Now, we may perhaps agree with Professor Johnson in this
matter, so long as we find the old farmer on his native heath,
and so long as he is exceptionally intelligent. But all farmers
are not old ; and it is particularly the young ones that stand
in need of advice, when they " go west." Moreover, old
farmers will frequently disagree widely in their estimate of the
qualities and value of a soil; and then who shall decide?
And who shall tell the hundreds of thousands of settlers and
emigrants annually occupying new lands of whose quality, at
present, no one knows anything, what they may reasonably
expect of their soil, apart from the bare assertions of inter-

J3. W. Hilgard — Objects and Interpretation of Soil Analyses. 185

ested parties ? How shall they know, in the absence of the
old farmer, whether in establishing their homestead in a given
locality, they do so for weal or woe, and in which direction
they are most likely to secure the highest returns and the
longest duration of fertility ; and in which direction the first
effects of soil-exhaustion will make themselves felt, and how
they can best be countervailed ?

If the agricultural chemist can do nothing to help the farmer
in these important questions, his practical utility will be lim-
ited indeed. And how is he ever to be able to render these
services, if he continues to ignore the chemical examination of
the soils, upon the strength of the " non possumus" pronounced
by some high priests ?

I cannot consider the testimonium paupertatis, implied in the
remark above referred to, as well founded. If the old farmer
can train his judgment in this matter so as to make shrewd
guesses, the agricultural chemist ought to be able to do a great
deal better ; for he should know all that the farmer does, and
a great deal more besides ; and, in addition, he should bring
to bear on the whole subject a well-trained mind, accustomed
to accurate observation and logical reasoning ? unlike the old
farmer who " knows" that " wheat turns into cheat" in unfavor-
able seasons.

The chemist who does no more than to give the farmer a
column of figures summing up to one hundred or nearly so,
opposite another column of unintelligible names, acts simply
as an analytical machine ; and even to the best of such ma-
chines, Professor Johnson 's remark will most truly apply. Their
enunciations are as enigmatical as those of the Delphic oracle,
and as little useful to the farmer as the most accurate ana-
lytical formula for calculating the motion and friction of water
in pipes would be to the hydraulic miner who stands at the
nozzle of the "monitor." Both the miner and the farmer
might be greatly benefited by the information conveyed, if
they could only understand it.

Since, then, the figures of a soil analysis, no matter how
made, do not interpret themselves, by what rule or rules shall
we be governed in interpreting them for practical purposes?

Of the older attempts in this direction, it is scarcely neces-
sary to speak. What remains of them at this time, may be
briefly summed up in the statement, that it is usual to judge a
soil by its absolute percentages of plant-food on the one hand,
and by such scanty information as we can elicit regarding their,
availability, on the other. As to what constitutes " much" or
il little" or ua deficiency" of any one ingredient, doctors differ
as widely as in respect to the classification of soils. It has been
usual to take a notoriously very rich soil as a type, and com-

186 E. W. Hilgard — Objects and Interpretation of Soil Analyses.

pare others therewith ; but even a cursory comparison shows
that, in many cases, soils showing percentages of plant-food very
much inferior to those of the type are nevertheless in practice
found quite as productive ; and that even in cases where pre-
cisely the same solvents had been used in their extraction.
These facts are too well known to require exemplification ; and
they led to the exclusive adoption, in the study of the part
played by the several soil ingredients, of the methods of culture
on artificial soils or in solutions of known composition.

The radical fault of these methods is that they necessarily
deal with plants placed under artificial conditions, and with
mediums of nutrition whose comparison with natural soils is at
best a lame one," necessarily so. until we shall know much
more than we do of the intimate condition and functions of the
soil as a whole, and of its ingredients, both severally and
jointly. And while the artificial cultures have given us some
exceedingly valuable information as to the relative importance
of certain soil ingredients, it is still held by some of the highest
agricultural authorities, that the only way to obtain practically
useful data as to the best method of soil improvement in any
particular case, is to go and try — first on the small, and then on
the large scale ; and when a particular kind of manure finally
fails of effect, to go and try again ; and so on.

Are we then really reduced to such empiricism as this — are
the permutations and combinations of nitrogenous, phosphate
and potash manures, all that agricultural chemistry can do for
the western farmer, when his " inexhaustible" soil begins to be
" tired?"

System of investigation adopted. — Unwilling to abide by this
lame solution of the problem, I have endeavored to solve it, or
at least to approach its solution, from a somewhat different side,
as suggested by. the opportunities offered in the agricultural
surveys of the newer States. Taking for granted the sound-
ness of the old farmer's judgment of the productiveness of a
soil from its natural vegetation, I have sought to determine, by
close chemical and physical examination of the soils in their
natural condition, the causes that determine this natural selec-
tion on the part of certain species of trees and herbaceous
plants ; while at the same time observing closely the behavior
of such soils under cultivation, their special adaptations, etc.
It goes without saying that this can be done most successfully
where, as in the Western and Southern States, virgin soils are
still obtainable, where manure is unknown, and where the sim-
ple history of each field can easily be gathered from the lips of
the settler who first broke the sod.

It is evident that when used in this connection, and made
uniformly and systematically, with a definite problem in view,

£L W. Hilgard — Objects and Interpretation of Soil Analyses. 187

each soil analysis becomes an equation of condition ; and that
by the proper treatment of a large number of such, by a logical
process of elimination, the problem of the function and value
of each soil-ingredient or soil-condition can be approached
with a better prospect of a solution in accordance with natural
conditions, than can be expected from cultures upon artificial
soils, or in solutions.

My first trials of the efficacy of this' method of investigation
were made upon the soils of the State of Mississippi, which,
fortunately, present extreme variations in character in almost
every direction, and upon every key, so to speak, of the soil
scale. But for this fact, I might, like many before me, have
abandoned in despair, the hope of attaining any definite results.
Some of the conclusions reached in this work have been given
in previous papers (this Journal, Dec, 1872, and others). Since
then, the material has been considerably increased, and quite
lately, the investigations made under the auspices of the census
office, upon the soils of the cotton States, have greatly added
thereto, and given a wider scope to the comparisons. The de-
tailed record and discussion of the facts so gathered will form
part of the Census report on cotton culture, and in any case
would be far too voluminous for presentation here. I must
therefore confine myself to indicating, in general, some of the
main points involved.

The taking of representative soil specimens is, of course, a mat-
ter of first importance, and sometimes of no little difficulty.
All those analyzed under my direction have been taken in
accordance with printed directions, with care in the selection
of proper localities, the discrimination between soil and sub-
soil, a record of depth, natural vegetation, behavior in cultiva-
tion, etc. As heretofore stated, I find that with such care, it
is perfectly practicable to obtain samples representing, typi-
cally, soil areas of many thousands of square miles ; especially
so when the subsoils are taken as the more reliable indices.

Method of Analysis. — In the selection of the solvent for mak-
ing the soil-extract to be analyzed, I have been guided by the
consideration, that minerals not sensibly attacked by several
days' hot digestion with strong hydrochloric acid, are not likely
to furnish anything of importance to agriculture, within a gen-
eration or two. If this assumption seems arbitrary, it at least
commends itself to common sense. The heavy draught made
upon the soil by the removal of crops cannot be sensibly
effected by the minute additions made to the available plant
food by the atmospheric or root action on such refractory min-
erals.

Regarding the strength of acid to be used, and the time neces-
sary to secure the solution of the important substances, I have

188 E. W. Hilgard — Objects and Interpretation of Soil Analyse*

caused investigations to be made by Dr. R H. Loughridge
(this Journal, Jan., 1874, p. 20), on a subsoil selected for its rep-
resentative position and derivation — a drift soil covering, prob-
ably, some 15,000 square miles in the uplands of Western Ten-
nessee and Mississippi, and perhaps as fully " generalized " in
its origin as can be obtained. The result of this investigation
was that hydrochloric acid of about the specific gravity of 1\L15
seems to exert the maximum effect, and that the extraction is
practically complete after a water-bath digestion of five daya
These conditions of digestion have been substantially main-
tained in all the investigations made under my direction. An
excess of time of digestion results simply in higher percentages
of alumina and soluble silica, or what is equivalent, in a far-
ther decomposition of kaolinite particles.

The methods of analysis used by me are substantially those
given in the first Kentucky Eeport, volume I, by Dr. Robert
Peter, with such changes as the progress of analytical chemistry
suggested. All the reagents have been especially prepared,
or purified, in the laboratory itself; porcelain beakers only have
been used in the digestions ; and generally every possible pre-
caution has been taken to insure correctness in the determina-
tion of the minute percentages of the important ingredients.

\ Numerous repetitions have, in most cases, confirmed the cor-

' rectness of the work.

Of other determinations, the one preceding all analytical
operations has been the determination of the " moisture-coeffi-
cient " of the u fine-earth," by exposing a very thin layer of the
same to a fully saturated atmosphere for at least twelve hours,
at a sensibly constant temperature. As previously stated, I
have in these determinations come to results differing material-
ly from those obtained by Knop, Schubler, and others ; prob-
ably because of the more complete fulfillment of the conditions
of full saturation of air as well as soil. I find that for most
soils, the absorption-coefficient is practically constant at tem-
peratures between +7° and +25° C. ; and contrary to the con-
clusions reached by Adolph Mayer.

I find that this coefficient exerts an exceedingly obvious and
important influence upon the actual productiveness of soils.
An investigation reaching beyond the temperature-limits men-
tioned, and also embracing the use of a partially saturated
atmosphere, has just been made in my laboratory and will short-
ly be published.

A determination of the total " volatile matter " of the soil,
that is, its organic matter and combined water, by ignition, is
made on the portion of soil used for the determination of phos-
phoric acid by means of molybdic acid. While this determin-
ation is necessary to the " summing up " of the analytical state-

M W. Hilgard — Objects and Interpretation of Soil Analyses. 189

merit, it is not in itself very instinctive, as it leaves the relative
amounts of the two substances altogether indefinite. A deter-
mination of the organic matter by combustion, or by extraction
with potash lye, is also unsatisfactory, because of the impossi-
bility of excluding from these determinations, a large amount
of comminuted, but altogether crude and unhumified, vegetable
matter ; which becomes very obvious under the microscope, or
in the process of silt-analysis. I have therefore adopted for the
determination of active humus, the admirable method of Gran-
deau, by the aid of which at least a uniform minimum determin-
ation becomes possible.

I have not devised any method for the direct determination
of the water of hydration, although there are cases in which it
would be very desirable to have this item, for the determina-
tion of the condition of the alumina and ferric oxide.

I have in a few cases determined the amount of silica soluble
in boiling solution of sodic carbonate in the crude soil. But
this determination is often beset with almost insuperable me-
chanical difficulties, from the diffusion of the clay in the alka-
line liquid. It does not appear to promise results of sufficient
importance to justify such labor; the more, as by the method
of Grandeau, the actual available amount of silica can probably
be better determined. But I have found the determination of the
silica soluble in the alkaline carbonates, in the " insoluble residue "
of the acid extraction, of very great interest. Evidently, in so
far as it is derived from the decomposition of clay, " kaolinite,"
it should stand in a definite ratio to the alumina dissolved by
acid, and this is often very strikingly the case. But sometimes
the soluble silica is so entirely out of proportion to (below) the
amount required to form kaolinite with the dissolved alumina,
as to prove that the latter is present in a different condition : the
only possible one in that case being that of hydrate. This
fact, doubtless, accounts for a great deal of the otherwise in-
comprehensible variations in the properties of soils and certain
clays, which I shall hereafter discuss. I should also mention
in this connection that I have strong evidence of the presence
of still another hydrous silicate, related to saponite, in some of
the tertiary " prairie soils " of the Southern States ; the peculi-
arities of which, when under cultivation, have seemed unin-
telligible.

I have not yet been able to extend the method of Grandeau
for humus extractions over a sufficient number of widely dif-
ferent soils of well known characteristics, to consider the claim
of its furnishing a definite measure of the available plant-food
in the soil, as definitely established. But thus far I have found
nothing to contradict this probable assumption, and much tend-
ing to its confirmation ; and I hope to be able to continue the

190 E. W. Hilgard — Objects and Interpretation of Soil Analyses.

investigation of its relation to the productiveness of soils, to a
definite conclusion. There can be no reasonable doubt that
what is extracted by Grandeau's ammonia water is at the com-
mand of the solvents employed by plants ; the only question is,
to what extent plants can readily go beyond. This of course
requires extended culture experiments, on a great variety of
soils.

The determination of the phosphoric acid and silica in the
residues from the ignition of Grandeau's extracts have already
furnished most important data concerning the cause of the pro-
ductiveness of some soils having comparatively a low percent-
age of phosphates.

As regards the determinations of nitrogen and its compounds
in the virgin soils thus far analyzed, I have omitted them in part
from want of time and proper appliances for these delicate de-
terminations, and partly from a doubt of their usefulness. The
constant variation and inter-convertibility of nitrates and am-
monia-compounds renders their determination at any given
time, of interest for that time only ; and as the nitrogen per-
centage of the mould of natural soils adapted to agriculture is
not likely to vary much, the humus-percentage may probably
be taken as roughly proportional to the total nitrogen of the
soil. A full investigation of this subject is, of course, also
called for. On the other hand, I find that the fulfillment of the
conditions of nitrification in the soil, is in all cases a condition
of its thrif tiness.

Interpretation of the analytical results. — Having obtained, as
above outlined, the percentage composition of a soil, how are
we to interpret these percentages to the farmer? what are
" high " and " low " percentages of each ingredient important
to the plant, whether as food or through its physical properties?

The first question arising in this connection, is naturally,
whether all soils, having what experience proves to be high
percentages of plant-food when analyzed by the processes
above given, show a high degree of productiveness?

So far as my experience goes, this question can, for virgin
soils, be unqualifiedly answered in the affirmative; provided
only, that improper physical conditions do not interfere with
the welfare of the plant.

But it does not therefore follow, as was at first supposed,
that the converse is true, and that low percentages necessarily
indicate low production. This will be apparent from a simple
consideration.

Suppose that we have a heavy alluvial soil of high percent-
ages, and producing a maximum crop in favorable seasons. We
may dilute this soil with its own weight, or even more, of
coarse sand, thereby reducing the percentages to one-half, or

E. W. Hilgard — Objects and Interpretation of Soil Analyses. 191

less ; and yet it will not only not produce a smaller crop, but
it is more likely to produce the maximum crop every year, on
account of improved physical conditions. If we compare the
root system of the plants grown in the original, and in the di-
luted soil, we will find the roots in the latter more fully dif-
fused, longer, and better developed ; not confined to the crevices
of a hard clay, permeating the entire mass, and evidently hav-
ing fully as extensive a surface-contact with the fertile soil
particles, as was the case in the undiluted soil.

How far may this dilution be carried tvithout detriment? — The
answer to this question must largely be experimental and must
vary with different plants; which is precisely what the farmers'
experience has shown, long since. A plant capable of devel-
oping a very large root-surface, can obviously make up by
greater spread, for a far greater dilution than one whose
root surface is in any case but small. The former flourishes
even on "poor, sandy" soils, while the latter succeeds, and is
naturally found on "rich, heavy " ones only ; although the ab-
solute amount of plant-food taken from the soil may be the
same in either case.

Now the conditions here supposed are frequently fulfilled in
nature, and more especially so in alluvial soils. Among many
striking examples that might be given, are the analyses of two
soils about equally esteemed for the production of cotton, both
equally durable, so far as experience has gone, and yet differing
so in their percentages of mineral plant-food, to the extent of
from three to five times.

In cases like these, which are not at all infrequent, the mere
percentage of plant-food in the soil showing the low figures,
would lead to a most erroneous estimate of its agricultural
value. But when, in addition to these, we know the fact that
in the one, the food-roots can exercise their functions to the
depth of three or four feet, while in the richer soil with ordi-
nary cultivation, they will rarely reach to a greater depth than
twelve or fifteen inches, the equal productiveness becomes
quite intelligible.

It is obvious, then, that without a knowledge of the respec-
tive depths and penetrability of two soils, a comparison of their
plant-food percentages will be futile. Nor is it feasible to agree
upon a certain depth to which all soils analyzed should be
taken. The surface soil with its processes of humification, nitri-
fication, oxidation, carbonic acid solution, etc., in full progress,
must always be distinguished from the subsoil in which these
processes are but feebly developed, and where the store of
plant-food — in which it is generally richer than the surface soil
— is comparatively inert. Hence the obvious importance of
specimens correctly taken, and the necessity of intelligent and
accurate observations on the spot

192 E. W. Hilgard — Objects and Interpretation of SoU Analyses.

I have attempted to make allowance for the cases of dila-
tion, as above noticed, by combining the results of the mechan-
ical with those of chemical analysis. In the investigation made
by Dr. Loughridge, of the several sediments obtained in the
mechanical analysis of the typical soil above referred to — see
this Journal, Jan. 1874 — it appeared that plant-food practically
ceased to be extracted from sediments exceeding 5™ hydraulic
value; and in re-calculating the percentages of soils of the same
general derivation, after throwing out the coarser sediments, we
often find very striking approximations to identity of percentage
composition, as well as of proportionately inter se. It is obvi-
ous, however, that this cannot be generally true; since inert
clay or impalpable silt must often come in as diluents. Never-
theless, I consider the mechanical analysis of soils (carried out
by the method heretofore described by me, and not in accord-
ance with that of the German experiment stations), as an almost
indispensable aid in judging fully of the agricultural peculiari-
ties of soils, especially when these cannot be personally exam-
ined in the field.

The concentration of the available portion of the plant-food of
soils in their finest portions is almost a maxim already, scarcely
needing the corroboration afforded by the investigation of Dr.
Loughridge above quoted. A " strong v soil is invariably one
containing within reach of the plant a large amount of impal-
pable matter, although the reverse is by no means generally
true. Striking corroborations of this maxim are afforded by
the steady increase of certain plant-food percentages in the
deposits of streams as we descend, and the proverbial richness
of " delta " soils is exactly in point

"High" and u loio" percentages and their interpretation. — I will
now state, as concisely as possible, some of the main points I
consider as substantially proven by the comparisons of soil
analyses made upon the uniform plan outlined above. The
detailed record upon which these conclusions rest, would render
this paper far too long, but will be given in the Census
report upon cotton culture.

1. Other things being equal, the thrifliness (i. e., present produc-
tiveness) of a soil is measurably dependent upon the presence of a
certain minimum percentage of lime.

The evidence I can present in support of this maxim is over-
whelming. It is obvious to the eye in thousands of cases, when
the significance of the occurrence of certain trees, esteemed by
the "old farmer" as certain signs of a productive soil, is once
understood. Almost all the trees he habitually selects as a guide
to a good u location," are such as frequent calcareous soils, using
the term, however, in a somewhat different meaning from that
usually given it That is, I find that in order to manifest itself

IP. W. Hilgard — Objects and Interpretation of Soil Analyses. 193

unequivocally in the tree-growth, the lime-percentage should
not tall below 0*100 in the lightest sandy soils; in clay loams
not below a fourth of one per cent, 0*250 ; and in heavy clay
soils, not below 0*500, and may advantageously rise to one and
even two per cent. Beyond the latter figure, it seems in no case
to act more favorably than a less amount, unless it be mechani-
cally.

The effect produced by the presence of such, or greater per-
centages of lime in the soils seems to be a kind of 4i aufschlies-
sung," an energizing or rendering active of that which otherwise
would remain inactive. This becomes evident at once in the
smaller insoluble residues from the acid treatment, yielded by
such soils; there being then oftentimes a complete dissolution
of the alumina, a large part of which ordinarily remains behind
in the shape of clay (kaolinite-particles). It would seem that
as regards the silicates, the carbonate of lime in soils performs
in a measure, the same functions as the caustic lime in Law-
rence Smith's method of silicate "aufschliessung." We have
an indication of the same action in the case of marls, whose
small percentages of potash and phosphates act so energetically,
and in which we so often find the potash in the highly availa-
ble form of glauconite grains; also in the displacement of
potash from zeolitic compounds, by lime or lime salts.

From the evidence before me, I should specify as follows,
the advantages resulting from the presence of an adequate
supply of lime in soils :

a. A more rapid transformation of vegetable matter into
active humus which manifests itself by a dark, or deep black
tint of the soil.

b. The retention of such humus, against the oxidizing influ-
ences of hot climates ; witness the high humus-percentages of
such soils, as against all others, in the Southern States.

c. Whether through the medium of this humus, or in a more
direct manner, it renders adequate for profitable culture per-
centages of phosphoric acid and potash so small that, in the case
of deficiency or absence of lime, the soil is practically sterile.

d. It tends to secure the proper maintenance of the condi-
tions of nitrification, whereby the inert nitrogen of the soil is
rendered available.

e. It exerts a most important physical action on the floccula-
tion, and therefore on the tillability of the soil, as heretofore
shown by Schloesing and by myself.

I may add that in the great majority of soils (excepting those
that are extremely sandy) the lime-percentage is greater in the
subsoil than in the surface soil. This is, doubtless, the result
of the easy solubility of calcic carbonate in the soil water,
which carries it downward and thus tends to deplete the sur-

194 E. W. Hilgard — Objects and Interpretation of Soil Analyses,

face soil. This fact is strikingly shown in the results of Lough-
ridge's investigation on the composition of the several sedi-
ments. (This Journal, January, 1874, p. 19).

The efficacy of lime in preventing " running-to-weed " in
fresh soils, and in favoring tne production of fruit, is conspicu-
ously shown in a number of cases.

This controlling influence of lime renders its determination,
alone, a matter of no small interest ; since its deficiency can very
generally be cheaply remedied, avoiding the use of more costly
fertilizers.

I have been unable to trace any connection of magnesia with
any of the important qualities of soils. Its percentage is usu-
ally larger than that of lime, frequently about double.

2. The phosphoric acid percentage is that which, in connec-
tion with that of lime, seems to govern most commonly the
productiveness of our virgin soils. In any of these, less than
five hundredths (005) must be regarded as a serious deficiency.
In sandy loam soils, one-tenth (0100), when accompanied by a
fair supply of lime, secures fair productiveness for eight to
fifteen years; with a deficiency of lime, twice that percentage
will only serve for a similar time. The maximum percentage
thus far found in an upland soil by my method of analysis, is
about a quarter of one per cent (0*250), in the splendid table-
land soils of West Tennessee and Mississippi. In the best
bottom (" buckshot") soil of the Mississippi, three -tenths
(0*30). In that of a black prairie of Texas, 0*46 per cent, this
being the highest figure that has come under my observation.

How the lime compounds contained in the soil act in render-
ing the phosphates more available, I do not pretend to discuss
at present A number (far too limited as yet) of determinations
made according to Grandeau's method, appear to confirm the
inference that calcareous soils yield to this treatment a larger
relative percentage of available phosphoric acid, than those
deficient in lime.

3. The potash-percentages of soils seem, in a large number of
cases, to vary with that of " clay ;" that is, in clay soils they are
usually high, in sandy soils low ; and since subsoils are in all
ordinary cases more clayey than surface soils, their potash-per-
centage is almost invariably higher also. 1*3 per cent K,0 is
the highest percentage obtained by rny method of extraction, and
that from the same soil that afforded the second highest phos-
phate percentage also, the u buckshot" of the Mississippi bottom,
noted for its high and uniform production of cotton. As the
same soil contains 1*4 per cent of lime, and is jet black with
humus, it may well serve as the type of a fertile soil.

The potash-percentage of heavy clay upland soil and clay
loams ranges from about 0*8 to 0*5 per cent, lighter loams from
0*45 to 0*30, sandy loams below 0*3, and sandy soils of great

E. W. Hilgard — Objects and Interpretation of Soil Analyses. 195

depth may fall below 0100 consistently with good productive-
ness and durability ; the former depending upon the amounts
of lime and phosphoric acid with which it is associated. Virgin
soils falling below 0*060 in their potash-percentage seem, in all
cases that have come under my observation, to be deficient in
available potash, its application to such soils being followed by
an immediate great increase of production.

Since but few soils fall below this minimum, my general
inference has been that potash manures are not among the first
to be sought for after the soils have become " tired " by exhaus-
tive culture. The universal preference given to phosphatic and
nitrogenous fertilizers in the west and south, is in accord with
this inference. In the older portions of the United States,
"kainite" is becoming more important, while in the alkali
lands of California, soluble potash salts often impregnate the
soil water.

4. In all soils not specially impregnated with sea or other
salts, the amount of soda extracted by the acid is considerably
below that of potash in the same soil, varying mostly from one-
eighth to one-third of the percentage of the latter. When much
more is found in such soils, a repetition of the determination
will usually show that the separation from magnesia was imper-
fectly mada I can trace no connection between the soda per-
centage and any important property of the soil, any more than
in the case of magnesia and manganese, albeit none of these is
ever absent from ordinary soils.

5. Sulphuric acid is found in very small quantities only, even
in highly fertile soils. From two to four hundredths of one per
cent (0*02 to 0*04), seems to be an adequate supply, but it fre-
quently rises to one-tenth (0*1) per cent, rarely higher.

6. Chlorine I have as a rule left undetermined, on account of
its constant variability and universal presence in waters, and
acknowledged slight importance to useful vegetation.

7. Iron, in the shape of ferric hydrate finely diffused, appears
to be an important soil ingredient en account of its physical,
and partly also its chemical properties. The universal prefer-
ence given to "red lands" by farmers, is sufficiently indicative
of the results of experience in this respect, and I have taken
pains to investigate its causes. The high absorptive power of
ferric hydrate for gases is probably first among the benefits it
confers. Eed soils resist drought better than similar soils lack-
ing the ferric hydrate. And here I must again call attention
to the strange fallacy in Adolph Mayer's experiments on the
wilting of plants in drying soils, from which he deduces as
probable, the maxim that the hygroscopic coefficient of soils is
a matter of indifference to plants. His plants in pots were not
under the conditions in which field crops are when called upon
to resist drought, whether from drying winds, or hot sun.

196 hi W. Bilgard — Objects and Interpretation of Soil Analyses.

Here the continuous rise of moisture from the subsoil tends to
keep up tire supply to the water roots, while at the same time
nutrition, as is well-known, continues almost unabated in air-
dry soils, so long as there is no injurious rise of temperature in
consequence of that dryness. But that is precisely the point
where a high moisture-coefficient comes into play, by prevent-
ing, in consequence of evaporation, a rise of temperature that,
under similar circumstances would prove fatal to the surface
roots of the crop in soils of low absorption power. In fact,
Mayer's conclusion is at variance with the ordinary experience
of centuries, repeated every day in the droughty regions of the
South and of the Pacific coast. It takes more than flower-pot
experiments to invalidate the universal designation of soils of
low hygroscopic power, as " droughty."

The moisture-coefficient depends in ordinary soils, upon one
or more of four substances, viz : (in the order of their efficacy),
humus, ferric hydrate, clay and lime. It varies in cultivat-
able soils from about 1*5 to 23 per cent at 15° C, and in a satu-
rated atmosphere. A pure clay rarely exceeds 12 per cent;
ferruginous clays show from 15 to 21 ; some calcareous clay
soils rise nearly as high, while peaty soils rise to 23 per cent
and even more, but the efficacy of the ferric hydrate depends
essentially upon a state of fine division. When merely incrust-
ing the sand-grains, or aggregated into bog-ore grains, it exerts
little or no influence, although the analysis may show a high
percentage. Sometimes soils highly colored show but a small
iron percentage, while yet, on account of very fine diffusion,
the advantages referred to are realized.

From 15 to 4*0 are ordinary percentages of ferric oxide,
occurring even in soils but little tinted. Ordinary ferruginous
loams vary from 3*5 to 7*0, highly colored "red lands" have
from 7 to 12 per cent, and occasionally upward to 20 and mora

Of course, a large amount of ferric hydrate facilitates the
tillage of heavy clay soils, and its color tends to the absorption
of heat. But I incline strongly to the belief that the benefits
of its presence are not confined to physical action. Prom the
fact that highly ferruginous soils rarely have a high percentage
of humus, it appears that the former acts as a carrier of oxygen
to the latter, and thus probably favors, especially, nitrification.

On the other hand, such soils are the first liable to damage
from imperfect drainage, overflows, etc. The reduction of the
ferric hydrate to ferrous salts, most commonly in the subsoil,
manifests itself promptly by the " blighting " of the crop. But
under natural conditions this can rarely occur, because a fre-
quent recurrence of conditions favoring reduction will inevita-
bly result in a gradual bleaching of the soil, and an accumula-
tion of its iron in the subsoil in the form of bog-ore or " black
pebble,"

JE, W. Hilgard — Objects and Interpretation of Soil Analyses. 197

In bringing forward this hasty summary of the conclusions
either definitely justified or foreshadowed by my investigations
on the subject of soil composition, I do not, of course, look for
their acceptance until the record and proofs shall be forthcom-
ing, as they soon will, in another publication. My present
object is to call attention once more to the fundamental and
practical importance of the subject of soil examination by all
available means, and to protest against the contemptuous,
unreasoning putting aside of the whole matter of soil analysis,
that has become current in works on agricultural chemistry for
some time past. If the chemists of Europe are content to
declare themselves incompetent to accomplish anything more
than mere guesses by the analysis of their long cultivated and
manured soils; if the same should even be held as regards the
well-worn soils of New England, the objection cannot be sus-
tained as against the virgin soils of our newer States and Terri-
tories, or even as against any soils that have not been manured
as yet, these two classes constituting, probably, four-fifths of
all the cultivatable lands of the United States. These soils
have been subjected only to natural, or to definitely ascertain-
able artificial influences. They are sensibly uniform over very
large areas, or at least, vary uniformly ; they still possess, in
part at least, their original tree or other growth, as produced by
natural selection. Is it reasonable that in the presence of such
opportunities American chemists should also declare themselves
incompetent, without even trying to accomplish that which
both in a theoretical and in a practical point of view, cannot be
held otherwise than as of prime importance?

No one can be more sensible than I myself, of the small
amount of progress made in the matter of a priori recognition
of the agricultural character and value, present and ultimate, of
soils, in the twenty-five years during which I have more or
less pursued the study of the subject. It would doubtless
have been otherwise had any one besides myself worked in this
field of research with similar objects and methods. By the
early death of Dr. David Dale Owen, I was deprived of the one
through whose initiative and encouragement I first entered
upon and persevered in this field, through the discouragement
freely bestowed upon me by my fellow-chemists ; and thus the
excellent work done by Dr. Eobert Peter, Dr. Owen's chemical
assistant in the survey of Kentucky and Arkansas, in the analy-
sis of the soils of those States, has so far remained without an
interpreter. If the facts, suggestions and views here presented
should be successful in attracting to this field of research some
of the attention now so lavishly bestowed on the investigation
of recondite organic compounds, the object of this paper will
have been attained.

198 B. Silliman — Mmeralogical Notes.

Art. XXXII. — Mmeralogical Notes; by B. Silliman.

1. Vanadinite and other Vanadates, Wulfenite, Cbocoite,

Vauquelinite, etc., from Arizona.

I HERE record the discovery of two important and very in-
teresting mineral localities, or districts, in the Territory of Ari-
zona, from one of which I have obtained vanadinite of remark-
able beauty of color and perfection of crystalline form, associa-
ted with almost equally beautiful wulfenite of an orange-red
color ; arid from the other, four, perhaps more than four species
containing vanadium. The last named district has also fur-
nished crocoite and vauquelinite never found before, I believe,
in North America.

I am greatly indebted to my faithful and intelligent corres-
pondent, Mr. George A. Treadwell, of Vulture, Arizona, for
sending me, for some years past, a great number of minerals
and ores collected by him in that Territory, among which are
those now to be described. I mention also, with pleasure, the
aid afforded me by Mr. Edward Farley, of Wickenburg, owner
of several interesting veins, and Dr. Jones, of Phoenix. Mr.
F. F. Thomas, lately in charge of Silverlead Furnaces, near
Silent, in Arizona, and Mr. John McDougal, Superintendent of
mines, have also contributed important data in extending our
knowledge of that interesting Territory.

Vanadinite. — This hitherto rare species promises now to be
comparatively abundant. In the so-called " Silver District," in
Yuma County, Arizona, about fifty miles north of Fort Yuma,
is a large area traversed by veins of quartz carrying argentifer-
ous galena, with salts of lead, but no gold, and rather exten-
sively explored. The lead salts which I have seen from this
region are wulfenite, of remarkable beauty, vanadinite, and
massive anglesite with galenite. Vanadinite occurs in three
mines, near together, the "Hamburg/7 the "Princess" and the
"Ked Cloud." The crystals of vanadinite are extremely beau-
tiful, alike for brilliancy of color, luster and perfection of form.
Only a single vanadate appears to occur in the Silver District;
but there may be an exception to this remark, since a greenish
yellow incrustation on one specimen may turn out to be volbor-
thite or one of the other amorphous vanadium minerals. All
the veins of this district occur, as I am informed by Mr. Thomas,
between a foot- wall of granite and a hanging-wall of porphyry,
specimens of which rocks I have in hand. The foot-wall of
granite is somewhat irregular, but the porphyritic hanging-wall
is well defined. I have not yet made sections of the latter rock ; it
closely resembles the augite trachytes of Nevada and elsewhere,

JBl Silliman — Mineralogical Notes. 199

the usual associates of silver ores the world over. All these
lodes abound in calcareous matter, but there are no limestone
beds in the vicinity ; and in the absence of any organic remains,
we are ignorant of the probable geological horizon.

" The Hamburg" mine has furnished the most numerous and,
on the whole, the best specimens of vanadinite. The crystals
vary in color from deep orange-red — deeper than potassium
bichromate, but not ruby — through lighter shades of orange-red
to reddish-yellow and brown. They are always highly lus-
trous. The size is small, the length being not over two milli-
meters and usually less than one; and the diameter about half
the length to equal dimensions. The hexagonal prisms are
modified usually oy one, sometimes by two planes on each term-
inal edge, and occasionally the angles are replaced. These crys-
tals are implanted singly and in crusts on a dark chocolate-
colored siliceous gangue, with occasional obscure crystals of
cerussite, and rarely a dark-colored cleavable lime-rock (impure
calcite).

The "Red Cloud" mine furnishes vanadinite of a rich orange-
red or flame-color, associated with beautiful orange-red wulfe-
nite. At the depth of 280 feet, measured on the slope of the
vein, wulfenite takes the place of vanadinite almost to its ex-
clusion. The crystals of vanadinite at this mine are smaller
and grouped in more confused masses than at the Hamburg
mine.

At " the Princess" mine, the vanadinite occurs in slender crys-
tals of a brilliant red color almost identical with that of croco-
ite, implanted upon white calcite. The habit of the species is
unlike either of those before mentioned ; the crystals are at
least four diameters long and are very slightly modified.
They are not over half a millimeter in diameter, but are very
perfect in form, luster and color. They have, naturally enough,
been mistaken for chromate of lead.

The genesis of the vanadates of these mines is obscure. A
single small specimen only of the galena has reached me. It
forms the nucleus of a surrounding mass of amorphous angle-
site, upon the outer surface of which appear obscure crusts of
vanadinite. Analyses of a series of samples selected on the
spot, by a careful examination might reveal the origin of the
vanadic acid.

Vulture district, as I have called it, another and quite dis-
tinct district in Arizona, has furnished, at a number of places,
vanadinite with other rare species. This area embraces the
country between the Hassayampa River on the west and
Agua Pria on the east, and extends in a north and south
direction from the well known Vulture Mine to Antelope
Mountains, Weaver district, on the road to Prescott. It is

Am. Joub. Sot.— Third Series, Vol. XXII, No. 129.— September, 1881.
14

200 B. Silb'man — Mineralogical Notes.

partly in the lower portion of Yavapai County, and partly
in the northern portion of Maricopa County. Within this
area are numerous veins of gold-bearing quartz carrying
lead and sometimes a little copper or perhaps both at the
same time. I have become familiar with the mineralogical
character of these veins through Mr. G. A. Treadwell : and
Mr. Edward Farley, owner of some of the mines which have
furnished the most interesting species of this area, has prepared
for me a sketch map on which the localities are laid down with
sufficient accuracy for identification by reference to the Gov-
ernment map.

Farley's u Collateral Mine/' about twenty miles northeast of
Yulture, is perhaps the most interesting locality of vanadinite
in this area. The vein is about four and a half feet wide,
and occurs in soft gray talcose rock. About one-half of
the thickness of the vein, on the hanging wall side, is
quartz stained green with chrysocolla, and chocolate- brown
with a ground-mass which I find carries vanadium, and
showing lemon-yellow stains resembling plumbic ochre, also
a vanadate. Any portion of these yellow and brown masses
(if pulverized, digested with dilute nitric acid, and the filtrate
treated with ether) gives a strong reaction for vanadic acid.
Unless led to test this gangue-stone for vanadium by the
occurrence of vanadinite in other parts of the vein, no
suspicion of its presence would be aroused. A seam of
very red ferric oxide with calcite follows next, and the red
oxide of iron reacts decidedly for vanadium, while the calcite
is penetrated with yellowish and white fibrous crystals of
vanadinite. Next, there is a seam, of about six inches, of very
soft material filled with abundant lemon-yellow acicular crys-
tals of vanadinite in tufts and aggregated masses, the whole
quite friable, forming the center of the vein, which also carries
in this zone masses of cerusite. The whole mass of this soft
material reacts very strongly for vanadic acid. Then follow,
on the foot wall, about twenty inches of vein-matter composed
of quartz with calcite. The calcite is penetrated with acicular
crystals of vanadinite arranged in threads and in stellar tufts,
usually not over a line in thickness, but occasionally opening
into small cavities, like geodes, lined with distinct hexagonal
prisms of this species. The common color is yellow but they
are often nearly white. The cleavage fragments of calcite
carrying the vanadium crystals form specimens of rare beauty.
Quartz, similar to that in the upper section of the vein, is
found in this lower member, and this is also somewhat stained
with copper silicates. In its open joints occur hexagonal crys-
tals of vanadinite of a fine yellow color ; they closely resembling
mirnetite, but give no arsenical reaction, and I failed to obtain

ft. SUV man — Mineralogical Xotes. 201

a trace of arsenic from the included crystals in the calcite,
when tested by soda and potassium cyanide in the closed tube.
This quartz carries crystals of vanadinite in habit very unlike
those which occur at the Hamburg mine in the Yuma district;
they are long slender needles hardly a line in thickness, of a
delicate straw-yellow color, quite transparent. They are asso-
ciated with others of a rich orange-yellow color and not so
well defined. There are also confused tufts of crystals of the
same species, not thicker than hairs, of a pure chrome-yellow
color, implanted in cavities in the red' iron-stained gangue.

Deschizite (?) — A mineral which may prove to be descloizite,
occurs among the ores of the Collateral Mine which have
reached me. It is found in blue-black and brownish-black
semi-transparent and very brilliant crusts, the individuals im-
perfectly developed ; hardness about 3—3*5 ; streak-yellow to
brownish-yellow. Alone in the closed tube it fuses and gives
off abundant water. It reacts very strongly for vanadium and
for lead, also for copper, manganese and zinc. Since this paper
was in hand I have received from Mr. Farlev, under date of
June 25th, additional specimens of this mineral not only from
the "Collateral" but also from the " Cbromate" veins near the
former, on one of which are seen very well detined, but very
small tabular crystals, the study of which will probably show
them to be the species indicated. They resemble some of the
forms figured by Websky from La Plata, province of Cordoba.*
We must await the arrival of more specimens before the study
of this interesting mineral can be completed.

Volborthiie (?) — A single well characterized specimen pro-
visionally referred to this species came among the products of
the Collateral Mines. It exists in small botrvoidal masses ad-
hering to the polished faces of deep red quartz crystals. The
streak is bright yellow. In thin scales the mineral is trans-
parent and of a clear olive-green. The luster is vitreous and
dull. No crystals were detected. Alone in the matrass it fuses
readily, adhering to the glass. It gives off no water and dis-
solves in dilute hydrochloric acid to a greenish solution from
which alcohol throws down the lead in tufts of» plumbic chlo-
ride. On charcoal it fuses to a black shining bead which
alone gives off lead fumes and copper appears on crushing the
bead in the agate mortar. With soda it gives a globule of
lead enclosing one of copper. Zinc oxide stains the coal when
the assay is gently heated. It may be that it will turn out to
be a new species.

An anhydrous cry ptocrystal line mineral containing vanadi-
um occurs among the " Collateral " ores. It varies in color from
light yellow-brown to black-brown; gives the reactions for

* Monatsbericht der Akad. zu Berlin, July, 1880, 6T2.

202 B. Silliman — Mlneralogical Notes.

Domeyko's chileite, but it is not a clay-like mineral. It yields
readily a globule of lead containing a nucletis of copper. No
arsenic was found. It occurs also in the " Chromate " vein.

Gold in coarse crystalline grains occurs in the quartz of thft
"Collateral" vein.

The Phoenix Mine, one mile east of the mine last named,
furnishes specimens similar to those just described. The van-
adinite is light yellow and deep orange-yellow to reddish, in
large, well-formed crystals, which react for chlorine but not* for
arsenic. The gangue isquartz which carries gold but no cal-
cite in the samples which have reached me.

Among the specimens sent to me by Mr. Farley on the 25th
of June, which I have just examined, I find crystals of van-
adinite in the gangue of both the "Collateral" and the "Chro-
mate" veins, quite unlike those before described and very
closely resembling in habit, color and form, the brilliant red
crystals from the Hamburg mine in the Yuma Silver District

The Montezuma lead mine, eleven miles east of Vulture and
southwest of Collateral, abounds in vanadinite which occurs in
drusy crusts of a rich deep yellow and brown color on masses
of cerussite. Observed with a lens these crusts are seen to be
well defined hexagonal prisms. It appears to be an abundant
source for the supply of vanadium.

At " the Frenchman's Mine," a gold-bearing vein, of about 18
inches thickness, consists of deeply iron-stained quartz, show-
ing amorphous yellow-green masses of a mineral very rich in
vanadic acid, and reacting for lead, copper and chlorine. It is
also hydrous. It may perhaps be mottramite. There is a buff
colored amorphous substance with it also rich in vanadinite.
Calcite occurs in the gangue.

There are other localities in this district in which vanadium
is found, but the foregoing will suffice.

Mimelite occurs in considerable masses north of the Domingo
mine on Castle Creek in the extreme northwest of the Vulture
District, as here described. I have seen only a single mass of
about 80 grams found by Mr. Farley. It was without gangue
or associated species, and quite amorphous.

From " Bethesda Mine, in Los Cerillos, New Mexico, I col-
lected in April, 1880, specimens showing greenish crusts of
vanadinite in botryoidal forms and sometimes nearly black.
It is there associated with wulfenite and cerussite. This vein
is the southerly extension of the " Mina del Tiro," worked by
Mexicans of old.

It is interesting to note the wide area over which this species
is now known to exist, compared to the single locality at Zim-
pan, in Mexico; where Del Rio in 1803 first identified it. No
doubt it will be found in equal or yet greater abundance at

B. Silliman — Minerahgical Notes. 203

other localities as the work of exploration goes on. Many years
since, in a paper on the Mineralogy of the Wahsatch and other
Utah ranges of mountains,* I called attention to the occurrence
of the molybdate of lead (wulfenite), as replacing the phosphate
(pyromorphite) among the salts of lead, tne latter being rarely
if ever found there. Subsequently the wulfenite of Tecoma
and of Eureka, in Nevada, confirmed this generalization, and I
have since had very frequent occasion to notice the wide distribu-
tion of wulfenite in New Mexico and Arizona. We may now
add vanadic acid as having the same wide distribution.

Wulfenite crystals of rare beauty are found in the "Red
Cloud1' Mine, already mentioned as furnishing the vanadinite.
The specimens sent me are from a depth of about 300 feet.
They show very solid tabular crystals of large size, brilliant
luster, and rich orange-yellow to orange-red color. The color
at once suggests the presence of vanadic acid, like the well-
known specimens from Wheatley Mines as detected by Smith.
But I have not found a trace of vanadic acid in these Red
Cloud or other Arizona wulfenites From the u Melissa Mine "
in Silver District adjacent to the Red Cloud, wulfenite is found
in octagonal prismatic forms, the basal plane being almost
wanting, in some specimens, giving them the appearance of
simple octahedrons. This interesting form I believe has not
been before observed in any American locality. The color of
the species at this locality is pure orange-red ; the gangue is
brown, almost black, calcite. The "Rover" is another mine
of the same district which furnishes wulfenite nearly identical in
form with the Red Cloud specimens, but of a little lighter
orange-red color.

Orocoite-group. — Three if not four of the species of this group
occur among the ores of the Vulture region, and especially in the
" Collateral'7 and "Chromate" veins. These two veins together
with the "Blue Jay" and the "Phoenix mine/' form a group
of singular mineralogical interest, furnishing, among more com-
mon minerals, the species, crocoite, phoenicochroite, vauquelinite,
joassite (?), vanadinite, volborthite (?), Descloizite (?), Chileite
(?), wulfenite. Vauquelinite occurs quite abundantly associated
with galenite and croc&ite in a gold quartz gangue or vein
stone. The genesis of the chromate is very manifest. The
nucleus of unaltered galenite is surrounded with a bright pea-
green and apple-green areola of vauquelinite, sometimes semi-
transparent, and uncrystalline. This green mass is succeeded
by crystalline and transparent crocoite of orange-red and cinna-
bar-red color giving the familiar scarlet and chrome yellow
streak. The crocoite as yet has not been found well crystallized.
Besides the associated species already named, occur cerusite, gold

* This Journal, III, iii, 195.

204 B. Silllman — Mmeralogical Notes.

and magnetite. The magnetic sand collected in washing the
gold out of the crushed vein stone was examined for chromite'
without success.

It is an interesting question, whence came the chromic acid T
Perhaps an analysis of the galenite may detect chromium in that
specie:*. Smith has described a meteoric chromium sulphide, Djiu-
breelite,* and there is no chemical reason why this species may
not coexist with galenite. In the paragenesis of. the chromates
in this district the change has evidently proceeded from without
inward, and the occurrence of specimens in which the whole of
the galenite is transformed is not unfrequent, as also the change
of the crocoite to the lemon-yellow phcenicochroite.

Small orange-yellow crystals occur in the vauquelinite of the
Vulture region, which may be the joassite ; but more study is
required before they can be proved to be this mineral.

In conclusion I will add that before the study of these inter-
esting localities can be complete a personal visit must be made
by a mineralogist to the mines, and sufficient material obtained
on the spot to allow of chemical analyses.

2. Thenardite from Rio Verde, Arizona Territory.

Some months since I received a lump of a saline mineral
marked "Salt," reported by my informant, Mr. Treadwell, of
Phoenix, to occur in abundance on the River Verde, in Maricopa
County. It proved, on examination, to be anhydrous sodium
sulphate or thenardite, a species which has hitherto been found
in very limited quantity. In an analysis in the Sheffield labora-
tory under the supervision of Prof. O. D. Allen, by Mr. Geo.
M. Dunham, its constitution was found to be as follows :

i. ii.

Chlorine 0095 0*097

S03 56-410 56-310

CaO 0120 0-130

MgO 0021 0-023

NaaO [42964] [43-070]

Insoluble 0-390 0370

100000 100-000

I. Na20 : S08 = 691 : 702; II. NaaO : S08 = 6-93 : 7*01.

The mineral is therefore nearly pure NaaS04. The insoluble
matter out, the impurities are only 0*24 per cent of the mass.

The specific gravity of a fragment quite free from visible
impurity, taken in petroleum, I find to be 2#681. This mineral
occurs in large masses, some of which, in the rough, are
distinctly crystals with imperfect faces, showing eminent cleav-
age in the direction of the basal plane of the prism and a
hackly cleavage in the opposite direction. The "insoluble"

* This Journal, III, xii, 109.

JR. Silliman — Miner alogicai Notes. 205

matter (=0*38 per cent) in the mineral — chiefly clay, gives it a
prevailing shade of yellowish gray. Its hardness is below that
of calcite ; luster vitreous ; fracture conchoidal to hackly.

Occurring in an almost rainless country, it has suffered little
change, small portions only at surface being altered to a dry
white powder of exanthalose, Na9S04, 2H,0.

As this is, so far as known, the only locality of this species
where it exists in great abundance, I have taken steps to
secure all the information available respecting it. Mr. Thos.
F. Hopkins, of Vulture, Arizona, has forwarded to me the
following statement which I present in his own words, in a
letter dated —

"Vultuke Mine, A. T., June 18, 1881.

" Mr. Boyd, a resident of the Verde Valley during the past five
years, is quite familiar with the large thenardite deposit, and fur-
Dishes the following details.

u The ' Salt Mine,' as it is popularly called, is situated about
two and one-half miles southwest of Fort Verde (the present post),
on the west side of the Verde River. Squaw Peak is distant eight
miles from Fort Verde, and this mine lies between these two points.

" It occurs on a ' bench ' about fifty or sixty feet above the
Verde River, and itself forms one of a series of benches gradually
sloping toward the river. The deposit crops out boldly in the
face of the bank, and seems to extend along a distance of from
eight hundred to one thousand feet. It occurs in a white chalky-
looking formation, and the surface opening is probably about ten
feet wide. From this opening immense masses have been carried
away during more than five years past, every rancher of the dis-
trict taking off huge wagon loads for the use of his stock, etc.
The deposit is solid, and is removed by blasting. It is not under
water at any time, for both its sloping situation and its elevation
above the river forbid such a condition.

u No systematic openings of the deposit have ever been made,
and hence its extent is not known. It is simply 'gouged out'
according to the whim and .convenience of each new comer; but
it seems practically inexhaustible."

I am informed by several persons who have seen this thenar-
dite used for the salting of cattle — among them my friend Mr.
James Douglass, Jr., who was recently in that portion of
Arizoua — that the animals resort to it very freely, licking it as
they are wont to do common salt, and with only good results.

Thenardite has been found in Nevada and elsewhere in the
arid regions of the West Coast, but not before in sufficient
quantity to be of commercial importance.

G. vom Rath (Zeitsch. f. Kryst.,) has lately named Lake Bal-
schasch, in Central Asia, as a locality the flat shores of which
furnish thenardite in very considerable quantity.

New Haven, July 8, 1881.

206 & M. Walton — Liquefaction and Gold produced

Art. XXXIII. — Liquefaction and Cold produced by the mutual
reaction of Solid Substances ; by Miss Evelyn M. Walton.

The mixing of two dry, finely-powdered salts, one or both
containing water of crystallization, is often attended by lique-
faction with decrease of temperature which in many instances is
very marked ; and sometimes there is also a decided change in
color.

A transparent, homogeneous liquid is sometimes, though
rarely, obtained, but generally the liquid holds in suspension
an insoluble compound or an undissolved salt either in the
hvdrous or anhydrous state ; and sometimes the consistency is
t£at of a stiff paste.

History. — It has long been known that freezing-mixtures
may be made by mixing some salt with ice or snow, and in
1875-6 Guthrie* determined the lowest attainable temperature
of quite a large number of such mixtures.

He found that the lowest temperature obtained with any
given salt was the same whatever its initial temperature ; also
that within certain wide limits this was independent of the pro-
portiQns used.

The earliest allusion I find made to freezing-mixtures,
formed by the use of salts only, is in the ninth volumef of this
Journal, where Ordway, in a paper on Nitrates, mentions
experiments in which the mixture of ammonium bicarbonate
with hydrated iron nitrate and with hydrated aluminum nitrate
was followed by a reduction of temperature from 58° to —5° F.,
and from 51° to —10° respectively. Subsequently^ he mixed
nitrate of iron with Glauber's salt and obtained a reduction of
32° Fahr.

Berthelot, in his recent work on Thermo-Chemistry, devotes
a brief space to the subject, and the Comptes Rendus, vol. xc,
pp. 1163, 1282, contains a communication from Ditte calling
attention to this wonderful phenomenon. He considers the
use of concentrated acids with hydrated salts, also mixtures
composed solely of salts. An example is given of ammonium
nitrate and hydrated sodium sulphate mixed together in a
mortar, the loss of heat being about 20° C.

Liquefaction of Salts. — As far as we know, when any salt sol-
uble in water is mixed with ice liquefaction is sure to follow,
and the minimum temperature is below 0° C. But, when salts
only are taken, the case is different.

In some instances liquefaction is very evident, in others
there is none at all, and in still others it is doubtful ; while the

* Phil. Mag., xxix, 314. f II, ix, pp. 30, 31, 33. % II, xxvii, p. 15.

by the mutual reaction of Solid Substances. 207

loss of heat is sometimes great, sometimes very slight, accord-
ing to the amount of liquefaction. Whether moistening will
take place or not must be decided in nearly every case by
actual trial, and in the preliminary experiments made with ref-
erence to this point I have mixed the substances in a wedg-
wood mortar.

From a large number of trials the following conclusions have
been drawn :

1. As a rule it is necessarv to liquefaction that one of the
solid substances used should be hydrated.

2. It is not necessary that each solid should be a salt
Moistening sometimes follows the mixing of a salt with an
acid, a salt with a base, or a base with an acid.

Ex. — Calcium chloride (CaCl, . 6H90) with tartaric acid (CJB.OA
Sodium sulphate (Na SO. 10H O) with potas. hydrate (KOH).
Potassium hydrate (KOH) witn tartaric acid (C4He06).

3. As when in the case of liquids, metathesis will take place
if a compound insoluble in the menstruum can be formed, so
with solids, if such a compound can result, metathesis is prob-
able with liquefaction.

4. If, by mixing two salts, an insoluble compound is pro-
duced, a mixture of two others like the new ones formed will
not, as a general thing, be attended by liquefaction.

5. When no insoluble compound is formed four bodies are
probably contained in the product, metathesis being partial ;
for it is sometimes observed that liquefaction seems equally
marked whether the two original salts are mixed or the two
bodies formed by their interchange.

6. The rule among liquids in regard to weak and strong acids
and bases seems to prevail with solids also, their action tend-
ing to promote or impede liquefaction.

7. When, by the admixture of two salts, oxydation or reduc-
tion can take place, there is again probability of liquefaction.

Ex.— SnCl9. 2H90 with HgCl9 liquefied.

" FeaCl6.12HL0 "
" CuCl9.2H90
" " PbCl9 no liquefaction.

In the last no change by reduction is possible.

A new substance. — A notable exception to the rule men-
tioned above, that one salt at least should be hydrated, is that
of AgN08 mixed with HgCl9. When these are rubbed to
gether there is decided moistening, which would seem to prove
that there is such a body as anhydrous nitrate of mercury
liquid at ordinary temperatures. On adding water a large resi-
due of silver chloride is observed.

208 E. M. Walton- Liquefaction and Cold produced

Evidences of chemical change. — When salts capable of meta-
thesis are mixed, in addition to liquefaction, change of color,
formation of an insoluble compound, and escape of a gas are
proofs of chemical reaction.

An important difference sometimes noticed between mix-
tures of salts in the solid and the liquid form is the escape, in
the former case, of some gas, as C9H409, CO,, HC1 or NH8.
The gas is dissolved by a liquid solution and eludes observa-
tion.

Classification. — Cases of liquefaction may be divided into
two classes ; the first including those in which there is mutual
exchange of base or acid ; the second, those in which there is
no interchange.

The mixture of lead nitrate with sodium carbonate is an
example of the first class. There is metathesis, and we obtain
lead carbonate, sodium nitrate, and ten equivalents of free

Pb(NO8)a + Na9CO8.10HaO
= PbC08 + 2NaN08 + 10HaO.

Hydrated product. — When iron nitrate is mixed with calcium
chloride thirty -six equivalents of water in some form are ob-
tained.

Fea(N08)6 . 1 8HaO + 3[CaCl 6HaO]
= tfefC], + 3Ca(N08)a + 36HaO.

Having mixed equivalent weights, the product was dried on
the smooth surface of a plate of plaster of paris which absorbed
the moisture, and an analysis showed the two new salts ob-
tained to be hydrated.

Therefore,

Fe2(NO,)6 . 18HaO + 3[Ca01a . 6H.01
= FeaClfl . 'l2HaO* + 3[Ca(N08)a . 4HaO] + 12HaO.

This experiment was repeated with a mixture of Fe9(N08)6.
18HaO with NaCl ; also of Ca(N08)9 . 4H90 with MgS04. 7H90,
and the first product was found to contain iron chloride, the
second nitrate of magnesium, both in the hydrated form.

At the more or less low temperature due to liquefaction,
there is naturally a tendency for salts to crystallize out from
the saturated solution.

The crystalline character is sometimes perceptible to the
senses, for the product often contains grains much coarser than
did the finely-powdered salts first taken.

Effect of temperature. — Experiments show that sometimes
liquefaction takes place readily at a temperature somewhat
elevated, but not at all at a low temperature. A mortar and

*It was found that Fo2Clfl . 12IIa0, and not FeaCl6 . 6Ha0, was formed.

by the mutual reaction of Solid Substances. 209

pestle which had been warmed by hot water were occasionally
used, care being taken that the heat should not be great enough
to cause either of the original salts to melt in their water of
crystallization.

When two salts capable of metathesis are mixed, chemical
action apparently begins immediately at every point of con-
tact. But there is a limit to the fineness of division which
may be effected by mechanical means, and the substance con-
sists of minute grains coated on the outside with the new pro-
duct, while remaining unchanged at the interior.

When liquefaction ensues, the interchange is continued
either because by removing the particles of the product, new
surfaces are presented, or because the liquid, penetrating the
granules, separates them into their molecules.

If the salts taken furnish little or no water in excess of that
required to combine with the new ones formed, the process of
interchange apparently soon ceases, unless sufficient heat is
supplied to prevent the constituents of the product from as-
suming the solid form.

Difficultly soluble salts. — When salts difficultly soluble are
used, moistening follows but slowly if at all. Tfhe molecules
of such substances are not easily separated with a limited sup-
ply of water, especially at a reduced temperature.

Liquefaction without chemical reaction. — The second class
referred to above includes mixtures of salt's of the same base,
or having the same acid ; and although it seems to be the
exception rather than the rule that there should be liquefac-
tion in such cases, yet this sometimes occurs.

Ex. — Fe2Cle . 6H.0 with Fea(N08)6 . 1 8HaO liquefied.

FeXJL . 12H O

FeCl " 4H„0* "

a a

FeSO. . 7H.0 " «

« Fe,Cl,.6H,0

Na,C,H,0,.6HaO « PbC,H,Oa . 8HaO

" " K.CJELO

« ZnCXoaH^O

Na^SO, . lOELO " ZnSO^VHO

" Li.SCVH.O

CaCL.eH.O " Fe.CL . 12H.0

" " CuCl„ . 2ELO

Some interesting experiments with caustic soda (NaOH)
showed that when it was used with anv hvdrated sodium salt
the combined water was liberated, evidently to satisfy the
affinity of NaOH for water.

KOH was also used with various hydrated salts, and in

* Of course a ferric and a ferrous base are not strictly the same, but ferrous
nitrate is too unstable a body with which to work except in the coldest weather.

210 E. M. Walton — Liquefaction and Gold produced

every instance liquefaction ensued. Apparently the hydrated
salt was attacked for the sake of its water, and the first reac-
tion seems to be appropriation of water by KOH, which is
doubtless followed by metathesis in most cases.

Liquefaction in the examples given above, however, can-
not be explained in this way. Neither is there metathesis,
and evidently double salts are not formed.

Having mixed equivalent weights of ZnS04.7H90 and
Na9S04 . 10HaO, the composition of the resulting solid part
was found not to be that of a double sulphate, there being an
excess of Na,S04.

Equivalent weights of CaCl9.6H,0 and Ca(N0t)9 . 4H90
were mixed, also of Fe9Cl6 . 12H90 and Fe9(NOt)6 . 18H.O, with
a view to analysis, but in each case the thin liquid disappeared
entirely into the plaster plate used for absorption, leaving only
a stain visible.

Theory. — These examples must be similar in nature to mix-
tures of salts with ice, which result in liquefaction, and solution
of the salts.

That the cold produced when ice and a salt are mixed is due
to rapid liquefaction of the ice is plain enough, but I have
seen no attempt made to explain the cause of the liquefaction,
until Ordway last year announced his theory of the *' diffusion
of solids," in an address* before the American Association for
the Advancement of Science.

We know that the molecules of a body are in a state of con-
stant oscillation, and that if a salt solution be placed in contact
with pure water, diffusion takes place until the molecules of
salt are equally distributed throughout the mass.

So, too, when the solid is placed in water, solution follows,
or, in other words, diffusion. Now, when a salt and water,
both in the solid form are in contact, there is probably the
same tendenc}T to interpenetration. But a mixture of water
and salt molecules cannot remain in the solid form except at a
low temperature, and the rigidity of the solid state is overcome,
because oscillations of the water and the salt molecules coope-
rate to produce a greater motion.

Graham found that although sodium chloride is not at all
deliquescent, yet the saturated solution has a great aflinity for
water. Therefore when the smallest quantity of the salt is
once in solution the first step is taken and the melting of the
ice continues rapidly. If this is the true explanation of the
action of sodium chloride on ice the problem is solved.

When salts capable of metathesis are used this physical phe-
nomenon is complicated by chemical reaction. Liquefaction
probably results when CaCla . 6H90 and Ca(N08)9 . 4H90 are

* Proceedings Amer. Assoc. Adv. Science, vol. xiix, p. 293.

by the mutual reaction of Solid Substances. 211

mixed, and in similar cases because the crystallizing point of
these two bodies together is lower than for each alone ; just as
the freezing point of salt water is lower than that of fresh
water, and as the fusing point of an alloy is sometimes below
that of either of its constituents.

Calorimeter. — For further experiments in which the reduc-
tion of temperature might be measured with some degree of
accuracy, it was desirable to secure a closed space in which
radiation and convection should be reduced to a minimum,
and the heat of the surroundings should be constant. A calo-
rimeter was therefore constructed somewhat like that used by
Berthelot in some of his investigations.

It consists of a covered circular tank of fourteen-ounce
tinned copper, of about twelve gallons capacity, placed in a
much larger wooden case, the space between the walls of the
tank and case being filled with loose cotton.

The upper surface of the tank has four wells, each to receive
a cylindrical vessel of polished german silver resting on cork
supports and having an air space around and under it. Each
of these vessels, containing a glass beaker of smaller diameter
(also on cork rests), is furnished with a closely-fitting cork
cover, perforated to admit a thermometer and a slender wooden
stirrer consisting of an upright rod with cross arms at bottom,
like a pug-mill.

The thermometers have each a long stem with the scale on
the upper part so that readings even to —40° C. can be taken
without raising the bulb from the mixture.

The tank is kept filled with water,* and this is frequently
agitated by a stirrer moved with a crank. The stirrer revolves
horizontally in the bottom of the tank, and having two blades
like a propeller, it agitates the water thoroughly from bottom
to top, the moistened part being always immersed. Over the
whole is a closely-fitting wooden cover also perforated for the
thermometers and stirrers.

The salts to be mixed, after finely pulverizing, were placed
in separate beakers within the calorimeter, and left for a time
to acquire a uniform temperature. The contents of one
beaker were then added to those of the other, the cover
replaced as quickly as possible, and the whole mixed vigor-
ously by twirling the stirrer. Liquefaction generally took
place in five to ten minutes and observations of time and tem-

?erature were then taken, slight agitation being still continued,
'here being four beakers two experiments can be carried on
at the same time, and as the cover is not in a single piece one
portion can be removed without uncovering the other pair of
beakers.

* Water of any desired temperature may be used.

212 E. M. Walton — Liquefaction and Cold produced

Equivalent weights were taken, seventy grams being used at
first, but this was afterward increased to one hundred grams.

From the following observations it will be seen that the
amount of radiation and convection is so small that it may be
disregarded :

Mixture of Mn(NO,)9 . 6HaO with Na9CO, . 10H,O. Tempera-
ture of water of calorimeter, 1 8° C.

Time. Temperature.

0 mill. 19° C.

4 — 9°

5 —10°

6 • —10-5°

10 —10-5°

11 —10°
21 — 7°
25 — 5°

Six minutes were required to reach the lowest point and
during the next five minutes there was a gain of but 05°.
Stirring was stopped at the end of eleven minutes.

Lowest attainable temperature. — In addition to Guthrie's dis-
coveries already mentioned, he found that when two salts
were used with ice the minimum temperature was unlike that
of either alone, each exercising an influence over the other.

Most of my experiments with the calorimeter were made for
the purpose of discovering whether or not the lowest attainable
temperature of a given salt when mixed with ice is the same if
that salt is produced in a freezing-mixture of two salts ; also if
it is independent of the initial temperature and the proportions
used.

The hydrated sulphate and carbonate of sodium were each
mixed with various nitrates, whereby nitrate of sodium was
produced and a sulphate or carbonate, usually an insoluble
compound, which I thought could not influence the result

The lowest attainable temperature of sodium nitrate with ice
is -17° C.

The following results were obtained with metals whose car-
bonates are without doubt anhydrous, insoluble compounds :

Initial
temp.

Lowest
temp. Loss.

Pb(NO,), withNa^CO,.

i< U U

10H,O

19° C.
0°

-17° 36°
-17° 17°

Ba(NO,),

u a

<<
u

21-3°
-1°

-18-7°* 35°
-17° 16°

Alu(NO,)„.18H,0 "

14°

-4°

-18° 32°
-18° 14°

Cu(NO,), . 6H,0 «

u
u

16-5°
-2°

- 18° 34-5°
-15°f 13°

* An insufficient quantity

was taken.

f Liquefaction proceeded very slowly.

by Hie mutual reaction of Solid Substances. 213

With the nitrates of zinc, manganese, iron and chromium the
results were not so free from modifying influences as I had
anticipated, basic carbonates being formed not wholly insoluble
at low temperatures.

The interesting fact was thus revealed that ferric carbonate
or basic carbonate exists in the liquid form at a low temper-
ature, say —20° C. The color is a deep red, and as the mixture
gradually warms CO, is rapidly given off', causing the contents
of the beaker, which was not at first more than half filled, to
overflow and insoluble FeaO, to be deposited.

Initial
temp.

Lowest
temp.

Loss.

Mn(NO,)„. 6H,0 with Na,CO, .

10H,O

18°

-14°

32°

U U

- 2°

-26°

24°

Zn(NO,), . 6H.0 "

20°

- le-r

S6'1°

u u

- 1°

-21-5°

20-5°

Cra(NO,), . 18H.O "
Fe,(NOJ,.18H,0 "

- 3°

-22°

19°

13*5°

-17°

30-5°"

u u

10-5°

-17°

27-5°

it u

- 3°

-24°

21°

Qitial temperature.

Lowest

JBt. 2nd.

temp.

45° 22°#

— 12-5°

39° 32°

- 4°

37° 32°

- 2°

It will be seen from these and the following results that the
minimum temperature is not independent of the initial temper-
ature; it was also found that the lowest point varies with the
proportions taken :

Pb(NO,)9 with NaaCO, . 10HaO

Fea(N08)6.18H90 «
Al9(N08)6.18HaO "

With the nitrates of magnesium and calcium the tendency
to metathesis is so slight that the liquefaction is not rapicl
enough to produce any great degree of cold, and with an ini-
tial temperature of — 2° there is no liquefaction whatever.

The time allotted for the completion of my graduation the-
sis, of which this paper gives the substance, rendered it neces-
sary to suspend for the present the continuation of these experi-
ments. This work was undertaken at the suggestion of Pro-
fessor Ordway, to whom the subject has been one of interest for
some years, but whom the pressure of other duties has prevented
from pursuing an investigation. He has, however, given con-
siderable thought to the matter, one of the results of which is
his theory of the "diffusion of solids." His predictions that
there may be liquefaction without chemical reaction, and that
the product obtained from the mixture of salts is sometimes
hydrated, were both confirmed by the results of my work. He
devised the calorimeter which was used, and I am indebted to
him also for valuable suggestions and advice.

Mass. Tnst. Technology, June 3, 1881.

* The temperature of NaaC03 . lOH^O could not be raised so high as that of the
other salts, without melting.

214 0. W. Huntington — Spectrum of Arsenic.

Art. XXXIV. — On t/te Spectrum of Arsenic ; by Oliver W.
Huntington. With Plate IV. (Contribution from the
Physical Laboratory of Harvard College.)*

It has been noticed, in the case of the spectrum of nitrogen
gas, that the spectrum obtained from an electric discharge of
low intensity through a rarefied atmosphere differs from that
obtained when the intensity of the discharge has been in-
creased by a Leyden jar. In the case of the low tension dis-
charge, the bands of the spectrum appear fluted on the more
refrangible side; but upon the introduction of a Leyden jar
into the circuit the fluted appearance at once vanishes, and the
spectrum breaks up into isolated bands. This difference has
been ascribed to a difference of condensation of the molecule.
Now as arsenic is allied to nitrogen, it was thought the same
difference might appear in the spectrum of arsenic, and we pro-
posed to make this a subject of investigation, For this pur-
pose, we first prepared two tubes, — one an ordinary Greisler tube,
such as is used for showing the spectrum with rarefied gas ; the
other as shown in fig. 1 of accompanying plate, for the spark
spectrum with Leyden jar. A small amount of pure metallic
arsenic was introduced into each tubet and they were then
repeatedly exhausted, each time replacing with hydrogen. After
the final exhaustion, the tubes were heated, in order to fill
them with the vapor of arsenic. But, upon passing the spark
through them, we could obtain no definite or satisfactory
result The arsenic spectrum was feeble, the hydrogen
brilliant, and the fluted indefinite bands which accompany the
hydrogen spectrum wholly obscured the phenomenon.

Judging from the statements in Roscoe's spectrum analysis
that these fluted portions of the hydrogen spectrum were
accidental and due to impurities, we attempted to get rid of
them in order to bring out the arsenic spectrum. We, there-
fore, prepared several tubes with pure hydrogen. We arranged
tubes with two outlets, in order to pass a continuous current
through the whole apparatus, including the Sprengel pump
which was connected with one of the openings. The hydrogen
was prepared from pure zinc and sulphuric acid, and most care-
fully dried. We would allow the gas to slowly pass through
the apparatus for twenty-four hours, then exhaust, and after
exhaustion heat the tube as hot as practicable under the
circumstances, then pass dry hydrogen and repeat the process
several times. Notwithstanding these precautions, we found,
after a great many trials with different tubes, that the fluted

* From the Proceedings of the American Academy of Arts and Sciences, Bos-
ton, 1881, p. 35.

0. W. Huntington — Spectrum of Arsenic, 215

and more or less diffused spectrum always accompanied the
four principal hydrogen lines. It being then impossible to
eliminate the diffused spectrum, we next tried alloying the
platinum electrodes with arsenic, and experimented with these
in a rarefied atmosphere of hydrogen, both with continuous
discharge of Ruhmkorff coil, and with interrupted discharge-
with Leyden jar. We now obtained very definite arsenic
bands, apparently the same in both cases ; but the effect was
momentary, and gave no opportunity for measurement. The
spectrum while it lasted was very striking; but, as soon as the
arsenic on the extreme point of the electrode passed off, the
characteristic spectrum disappeared.

We were by this experience led to contrive the following
apparatus, by which we obtained the desired result, and the
same may be useful in experiments on the spectra of similar
volatile substances. A longitudinal section of the tube, one-
half of the original size, is shown in fig. 2 of plate. The
Ewtions A A' and A" are of rather coarse thermometer tubing.
B' is a tube left open at B, and drawn to a capillary point
at B'. The substance to be examined, after being reduced to
powder, is introduced through the opening at B until the
tube is about half full. Then one end of a platinu'm wire is
buried in the substance, and the other end is fused into the
tube at B, thus closing the opening. After the hydrogen has
been allowed to flow through the tube a sufficient length of
time, the opening at A is closed by a nipper tap, and the tube is
exhausted at B". Now upon connecting B with the negative
electrode, and C with the positive electrode, of a small induc-
tion coil, we have the vapor of the substance in the tube BB'
carried in the current through the tube A' where the spectrum
may be observed.

One advantage of this particular form of tube is, that, in
order to compare the spectrum of the substance with that of
hydrogen, we have only to reverse the current, making C the
negative pole, and then all the lines except those of hydrogen
at once disappear.

The arsenic spectrum thus obtained is very brilliant, and
consists of numerous well-marked sharply defined bands. The
bands are most numerous and brilliant in the green, and these
give the prevailing tone to the spectrum. But there is one
very striking yellow band, and there are also several bands in
the blue and violet. Then in the red there is an interesting
double band, the two members of which are the same distance
apart as the two D lines. In addition, there may be also a
more or less diffused spectrum, which in some parts cannot be
distinguished from the similar diffused spectrum of hydrogen,
and it is worthy of remark in this connection, as indicating the

Am. Jour. Sol— Third Series, Vol. XXII, No. 129.— September. 1881.

216 0. W. Huntington — Spectrum of Arsenic.

purity of the material used, and also that the diffused spectrum
above referred to cannot come from the material of the tube,
that no trace of the sodium line was seen. No account was
taken of the diffused spectrum, as it appeared only when the
battery was unusually strong.

In speaking of the diffused spectrum of arsenic, we do not
mean the same kind of diffused spectrum as mentioned abov6
in connection with nitrogen. The diffused arsenic spectrum
appears to be composed of innumerable faint lines, wholly
independent of the other more brilliant characteristic arsenic
bands ; and we use the term " diffused" only for convenience,
to express that the lines are very faint and too numerous to
measure. And we wish to call particular attention to the fact
already intimated, that the spectrum of arsenic as it appears
with the silent discharge bears no resemblance to the fluted
spectrum of nitrogen, but consists of sharply defined isolated
bands, the more prominent of which, at least, are not altered
when the intensity of the discharge is increased by a Leyden jar.

The arsenic employed had been carefully purified by sublima-
tion, and preserved under distilled water. We used for
measuring the .wave-lengths of the spectrum lines the spectro-
scope described by Professor J. P. Cooke.* In this instrument,
the train of prisms can be adjusted accurately to the angle of
minimum deviation, which was observed in each case. We
used five flint prisms of 46° angle each, and to reduce the
angular measurements to wave - lengths, we employed the
method described by W. M. Watt in his " Index of Spectra."

In the first place, we measured with care the angles of
minimum deviation of the most prominent Fraunhofer lines,
and verified and somewhat multiplied the data by measuring
also the angles for characteristic lines of the hydrogen, lithium,
sodium, thalium and strontium spectra. These we combined
with the wave-lengths of the same lines given by Angstrom,
by ordinates and abscissas in the usual way, and the curve
drawn through the points so determined was so regular
and of so small curvature, that it was easy to interpolate
with minutes of arc to five tenth-metres of wave-length, as
usually expressed.

The instrument is capable of reading to five seconds of arc,
and with the full bank of ten prisms it would give the wave-
lengths to tenth-meters with perfect accuracy. With the com-
paratively feeble light of the arsenic spectrum, as we first
observed it, we did not think it advisable to use the full power
of the instrument. We therefore used five prisms, as stated,
and read to one minute of arc. We always began each series
of observations by setting the cross-wire of the micrometer on

* This Journal, xl, November, 1 865.

Chemistry and Physics. 217

the sodium line, after the telescope had been adjusted to the
angle of minimum deviation of this line as first observed.
There was seldom any observed difference in this angle. But
when, by change of temperature, or otherwise, an alteration of
two or three minutes had taken place, we found, on readjusting
the cross-wire, that the relative position of the spectrum lines
was, to the limit of accuracy of our measurement, wholly un-
changed.

We give below the table of wave-lengths of the principal
lines of the arsenic spectrum.

6023 tenth-meters.

5230 tenth-meters.

6013

5195

5853

((

5163

5833

»<

5103

5813

5013

5743

((

4941

5653

((

4623

5563

((

4593

5498

4493

[5340]

4463

((

5323

((

4313

5245

((

The wave-lengths printed in heavy type denote the bands
which are most brilliant and give character to the spectrum.
The other lines are less constant and less distinct, and in some
instances may be due to accidental causes.

We were surprised to find among the bright lines, that the
one which in the table is enclosed in brackets corresponds to
the green thalium band, and upon examining the spectrum it
appeared evident that thalium must be present in the arsenic
in large quantities, as the thalium band was fully as bright as
any of the arsenic bands.

The diagram, fig. 3 of Plate IV, gives some idea of the
general appearance of the arsenic spectrum.

SCIENTIFIC INTELLIGENCE.

I. Chemistry and Physics.

1. On the {Spontaneous Oxidation of Mercury and other Metals.
— Berthelot has submitted to experimental verification the ques-
tion so long discussed without final settlement, whether mercury
dissolves the oxygen of the air and oxidizes, even at ordinary
temperatures. Perfectly pure mercury was placed in a rectangu-
lar dish of porcelain exposing a surface of 500cma about, and
covered loosely with paper. After 48 hours at a temperature of
10°, the metal yielded a slight pellicle to a tube of glass passed
over it. This was removed from day to day and showed on
analysis the presence of mercurous oxide. The slow oxidation of

218 Scientific Intelligence.

pure mercury in contact with air can no longer be doubted. The
same is true of iron, zinc, cadmium, lead, copper and tin. Now
thermic data explain this phenomenon. For each equivalent of
oxygen fixed by the metal, iron (rust) evolves 31*9 calories; tin
34*9; cadmium 33*2; zinc 4T8 ; lead 26 *1 ; copper 21'0, and
mercury 21*1. This oxidation in the air, however, is not appre-
ciable in the case of metals whose heat of oxidation is small.
Silver, for example, evolves only 3*5 calories per equivalent of
oxygen absorbed. The fact that a reaction begins spontaneously
only in the case where a notable evolution of heat takes place, is
a result not un frequently observed ; seeming as if there was a
certain resistance to be overcome, a certain preliminary work to
be accomplished in order to determine the reaction. But this
action becomes more prompt and more easy when an auxiliary
agent is made to intervene capable of combining, with evolution
of heat, with the substance at first formed; so that the total
energy in action becomes greater. This is the action called in
early times pre -disposing affinity. If, for example, mercury be
placed in a flask and hydrogen chloride gas be mixed with the
air in contact with it, the walls of the flask will be covered after
a time, with mercurous chloride. Now hydrogen chloride alone
does not act on mercury at all, under these circumstances;
the oxygen of the air intervenes, the reaction Hg2+HCl gas,
-+-0=Hg3Cl-fHO liquid evolving 53*4 calories.* So silver,
which is not acted on by oxygen alone, is easily converted into
chloride in presence of hydrogen chloride gas in addition, the
reaction Ag+HCl gas+0=AgCl-|-HO liquid evolving 41*7 cal-
ories. So silver in contact with air is attacked by a solution of
sodium chloride, copper by hydrochloric and acetic acids, lead by
acetic acid, etc. In the case* of mercury and hydrogen sulphide,
in presence of air, the hydrogen is oxidized, the sulphur finely
divided is precipitated and acts upon the metal. The same mech-
anism takes place with silver. — Bull. Soc. Ch., II, xxxv, 487,
May, 1881. g. p. b.

2. On Hesperidin, a Glucoside of the Aurantiacece. — Tiemann
and Will have examined at length a glucoside found by PfefFer
in the fruit of Citrus vidgaris and Citrus medica, and called hes-
peridin. It appears to be universally diffused through the family
of the Aurantiacese and is most readily prepared from the dried,
unripe officinal orange {Fructus aurantii immaturi). The
coarsely pulverized fruit was extracted with water so long* as
lead acetate gave a precipitate in the extract. The residue was
then treated with a mixture of equal volumes of alcohol and
water, containing 1 or 2 per cent of sodium hydrate, until the
solution was no longer colored. From this last solution, mineral
acids precipitate crude hesperidin. This is boiled with 90 per
cent alcohol to remove coloring matters and the residue is dis-
solved in very dilute potash solution, and precipitated by a slow
current of carbon dioxide. It is well washed and dried. As thus

*The symbols in theno equations represent equivalents, not atoms.

Chemistry and Physics. 219

obtained, hesperidin is a white, odorless and tasteless mass, con-
sisting of fine microscopic needles, insoluble in ether and nearly
so in water. Alcohol takes up only small quantities, though by
distillation off of the solvent it may be obtained in somewhat
larger needles. It fuses at 251° and decomposes. On analysis it
gave the formula C H26012. It possesses weak acid properties, is
soluble in alkalis and reprecipitated by acids. On heating with
water and sodium amalgam for a few minutes, filtering the orange
solution and adding an acid, a precipitate falls which dissolves in
alcohol with a magnificent red violet color, with a blue violet
fluorescence. By the action of dilute sulphuric acid hesperidin
splits into dextrose and hesperitin, C]flHJ406. This, by the action
of alkali, splits into phloroglucin and hesperetinic acid ClftH 04.
Fused with potassium hydrate this acid yields protocatechnic
acid C7H604. Methyl-hesperetinic acid, oxidized by permanga-
nate, gives veratric acid (dimethylprotocatechnic acid). Acet-
hesperinic acid when thus oxidized yields isovanillic acid. Hence
hesperetinic acid is identical with isoferulaic acid. From these
reactions the author gives the following as the rational formula of

C CH-— CH-L-CO — O )
hesperetin : C,H, ) OH(3) (3)HO I C„H3. The quantity of

|0CH,(4) (5)HO)
hesperidin which is contained in the dried fruit, about 10 per
cent, suggests the importance of this glucoside to the growth of
the plant. — Ber. Berl. Chem. Ges., xiv, 946, Apr., 1881. g. f. b.

3. On a new series of Volatile Organic Bases. — Meyer and
Treadwell, by the reduction of nitrosoketones by sodium-amal-
gam or by tin and hydrochloric acid, have produced a series of
well characterized bases of the formula CnHan_1N2, which distil
without decomposition and form with water crystallized com-
pounds. The name ketines is proposed for these bases, and one
member of the series, dimethylketine, has already been described
by Gutknecht, who obtained the platinum salt pure. — Ber. BerL
Chem. Ges., xiv, 1150, May, 1881. g. f. b.

4. Photometry of the Fraxinhofer lines. — Vierordt employs
the peculiar slit of his spectrophotometer to measure the relative
intensity of the Fraunhofer lines, using the simple fact that the
strength and sharpness of these lines varies with the width of the
slit of the collimator. His paper consists merely of a preliminary
note, and measurements are promised ; he believes that the varia-
tion in light-intensity of the dark lines will prove the most char-
acteristic feature of the spectra of heavenly bodies. — Annalen
der Physik und Chemie, No. 6, 1881, p. 338. j. t.

5. Intensity of Sound. — Overbeck has endeavored to obtain
quantitive measurements in acoustics by the use of the micro-
phone. It is evident that if we possessed a sufficiently delicate
electro-dynamometor an electrical measure of the intensity of
sound waves could be obtained. In place of such an instrument
Overbeck uses a galvanometer which is affected by the varying
resistance of the microphone when the latter responds to sounds

220 Scientific Intelligence.

of different intensity. It is found that the microphone, used in
this way, is far more sensitive than the ear to changes of tone —
that it can be used with great effect to study resonance — the
reflexion of sound in different rooms, and the influence of the
change of temperature upon the propagation of sound waves.
The author proposes to extend his investigations. — Annalen der
Physik und Chemie, No. 6, 1881, p. 222. j. T.

6. Reversal of the lines of Metallic Vapors, — Professors LrvE-
ing and Dewar have succeeded in reversing ten of the brightest
lines of iron, in the blue and violet, by passing an iron wire
through one of the carbons between which the electric arc is
formed. When iron is put in a lime crucible through which the
voltaic arc is formed, and fragments of magnesium are dropped
in from time to time, most of the strong ultra violet lines of iron
are reversed. The magnesium appears to supply a highly reduc-
ing atmosphere, and to carry the iron vapor with it. It also
appears to produce a continuous spectrum in certain parts, and
against this the iron lines are sometimes depicted on the photo-
graphic plates sharply reversed. Potassium ferrocyanide intro-
duced into the arc acts in a similar manner. Iron wire fed
through a perforated pole reverses certain lines (wave length
2492 to 2480) and spreads out the lines into broad absorption
bands. These effects are enhanced by leading into the crucible,
through the perforated upper carbon, a gentle stream of hydrogen
gas. — Nature, June 30, 1881, p. 206. J. t.

7. Change of State. — There are two types of change of state
which are usually recognized : the ice water type, in which the
change takes place first at the surface and gradually extends, the
ice remaining solid up to the melting point, and the sealing wax
type, in which softening takes place throughout the entire mass,
on elevation of temperature. Mr. J. H. Poyoting defends the
solid liquid type theory. He shows that it is easy to give an
explanation of the phenomenon of melting and freezing by sup-
posing, on the theory of the passage of molecules, "that if the
temperature is not at the melting point the substance in the state
with the greater vapor-tension will lose at the expense of the
state with the less vapor-tension." The alteration of the melting
point by pressure is explained by the supposition that pressure
alters the vapor-tension, and therefore the rate of escape of mole-
cules, and that this alteration is different for the two states. Mr.
Poynting gives, on this supposition, a new proof of Sir W. Thom-
son's formula, which expresses the relation between the vapor-
tension at plane surfaces of a liquid and the vapor-tension of the
same liquid above its surface in capillary tubes. The remarkable
result is deduced that if ice can be subjected to pressure while
the surrounding water is not so subjected "the lowering of the
melting point per atmosphere is about 11 J times as great as when
both are compressed." An account of certain experiments is given
which appear to support this theoretical conclusion. A possible
explanation of Professor Carnelly's " Hot Ice " is deduced from

Geology and Mineralogy. 221

considerations of the isothermals for ice water. The place of
this "hot ice" would seem to be represented by the prolongations
upward of the ice isothermals beyond the horizontal line to where
they meet the line of no pressure. The critical point, which is
roughly fixed at 14°C, would then be above the limit to the tem-
perature of hot ice in a vacuum. " It is also pointed out that the
sealing wax type of melting is probably similar to the change of
ice into water below the lower, or above the upper, critical points,
if these exist." — Phil Mag., July, 1881, pp. 32-48. J. t.

IL Geology and Mineralogy.

1. Geology of the Province of Minas Geraes. — From two im-
portant memoirs published by Prof. Henrique Gorceix in the
Annaes da JEkcola de Minas de Ouro Preto, noticed in our last,
we condense the following account of the geology of the central
part of the province of Minas Geraes, Brazil.

The greater part of the central portion of the province of Minas
Geraes is constituted by the great chain appropriately named Serro
do Espinhaco. This chain is formed principally of quartzose and
schistose rocks, to which are joined granitic gneiss and even true
granites, mica schists, dikes and intercalated beds of diorite and
finally small deposits of anomalous rocks containing tourmalines,
disthene and other minerals.

The quartzose rocks are true quartzites consisting of irregular
grains of hyaline quartz without cement. To the quartz in these
rocks are united two other substances, a green mineral and mica-
ceous iron which serve to characterize two principal geological
horizons. The inferior division of the quartzites is characterized
by the presence of a soft green unctuous mineral generally described
as talc, but which unlike talc contains only an insignificant propor-
tion (1 to 3 per cent) of magnesia with a large proportion of
alumina, and the alkalies, potash and soda. The presence of small
quantities of iron, manganese and chrome probably determines its
green color. These quartzites are known by the name of ita-
columites and are in the lower division characterized by a
schistose or flaggy structure.

In the quartzites with the green substance two subdivisions are
recognized at Ouro Preto. The lower one consists of flaggy beds
which near Ouro Preto are inclined at an angle of 25° or 30° to
the southward. The second and more important division consti-
tutes the peak of Itacolumi, and consists of more massive beds
with an easterly inclination. Both divisions are traversed by
auriferous veins, in which the matrix is -generally common iron
pyrites or arsenical iron pyrites.

In some cases, as at Morro Velho, Pary, etc., quartz enters in
relatively small proportions in the vein matter and the gold is
very fine, and in small but constant quantity. When, on the con-
trary, the pyrites disappear and the vein is formed almost exclu-
sively of quartz, the gold is in larger grains but very irregularly
disseminated in the vein rock.

222 Scientific Intelligence.

The second division of the quartzites is characterized by the
substitution of the green matter by micaceous iron and often by
the disappearance of the quartz ; these pass to beds of iron ore
known by the name of itabirite. The beds of itabirite attain in
places the thickness of more than 200 metres and by the abundance
and purity of the mineral and the facility of extraction constitute
the richest iron ore deposits of the world. The iron is often accom-
panied by oxide of manganese which in places enters in a propor-
tion as high as 9 per cent, or more.

In the friable itabi rites gold is often found disposed in a
manner which seems to be peculiar to Brazil. The gold appears
disseminated in the rock in scales analogous to the scales of iron
oxide, these scales being sometimes joined together so as to form
large nuggets. The distribution of the gold in the rock appears
to be irregular but it is probable that the rich lines have, like veins,
a definite direction. The absence of sulphides which characterize
the gold bearing rocks inferior to itabirites, is worthy of note.
The only substance which appears to mark the presence of gold
is a white lithomarge appearing in little pockets in the rock.

The schistose rocks are of very variable characters, and when
fully studied, either from a geological or mineralogical point of
view, will fall into several divisions. They are generally shales
passing at times to true slates ; soft, greasy to the touch and of
various colors, green, yellow, red, black, etc. These schists have
generally been described as talcose, but analysis proves them to
be argillaceous, rich in alkalies and with but a trifling proportion
of magnesia.* True talcose rocks consisting of soapstone or pot-
stone are however met with in small basins in the midst of the
schists. The schists may be divided into two groups with
reference to their relations to the itabirites, namely, those below
the itabirites characterized by brilliant mica-like scales, extreme
softness, and a relatively small development of the schistose
structure, and those superior to the itabirites characterized by a
greater predominance of the argillaceous character and of the
schistose structure.

These schists are everywhere metamorphosed, but in the north
of the province in the Jequitinhonha and Arassuahy basins the
alteration of the rocks is more pronounced than in the region
farther south and the rock becomes crystalline, passing to mica
schist and other types of crystalline rocks. These crystalline
schists perhaps belong to another geological series. This change
to the crystalline character is accompanied by the appearance of
numerous veins of quartz accompanied by tourmalines, staurolites,
spodumene, chrysoberyls, etc.

In the series of schists the gold-bearing veins are less numerous
than in the other groups described, and are of inconstant richness.
In places gold also appears distributed in the rock in a manner
analogous to that in the itabirites but this only occurs in the parts
contiguous to the latter rock. The group of schists is also

* These are evidently hydromica schists.- -Eua

Geology and Mineralogy. 223

characterized by the presence of isolated masses of crystalline
limestone or marble.

The determination of the geological age of these various rocks,
and even that of the relative ages of the different groups, is ren-
dered difficult by the absence of fossils, and by the excessive
dislocation of the beds by folding and faulting, faults being
particularly numerous and giving a peculiar character to the moun-
tains of the region, which generally present a moderate slope on
one side and a precipice on the other.

The rocks above described have been referred to the Tertiary
and Secondary ages ; but there are good reasons for considering
them more ancient than the limestones of the Sao Francisco in
which Prof. O. A. Derby found fossil corals which indicate that
these are much older than the Secondary and belong to the Paleo-
zoic age.

The more modern rocks are represented by the peculiar iron
conglomerate denominated canga formed on the surface from the
fragments of the underlying rocks and which continues to form
to-day, and by deposits of lignite of Tertiary age as is proved by
the fossil plants and fishes contained in them.

A fact of considerable interest, from an agricultural point of
view, is the uniform presence of a notable proportion of alkalies,
particularly potash, in all the schistose rocks examined, and the
absence of lime in the same rocks. The first fact explains the
wonderful fertility of many of the soils derived from the decom-
position of the schists, and the second indicates the proper fertil-
izer for the more sterile soils.

Of the precious stones found in Minas, the deposits of topazes,
situated near Ouro Preto, have been most studied. Topazes
and the still rarer euclases are found in their primitive formation
in a small basin west of Ouro Preto in which several mines have
been opened. The rocks of this region consist of schists and
quartzites with the green substance, the beds being inclined at
angles of 30° to 50° to the eastward. The schists are the pre-
dominant rocks and belong to the two divisions already described
of clay schists and greasy or unctuous schists. They contain
pyrophyllite and embedded octahedral crystals of iron oxide hav-
ing the form of and resulting from the alteration of pyrites.

The various topaz mines that have been opened lie along two
parallel lines running W.S.W. In the Boa Vista mine which is
a deep open cut, the beds explored are unctuous shales of several
varieties containing the talc-like mineral already mentioned.
These beds are inclined to the eastward at an angle of 40° to 50°
and are covered by superficial deposits of sand and conglomerate.
The gems occur in an irregular fracture or vein filled with a soapy
clay or lithomarge and running about W.S. W., or perpendicular
to the strike of the country rock. The vein divides into branches,
some of which sometimes accompany the bedding, and is often
split up into pockets in which the topazes are of greater size and
more abundant. Rarely topazes are found without the lithomarge

224 Scientific Intelligence.

in a brown clay rock to which the gem-bearing veins appear to be
confined. The other minerals accompanying the gems are quartz
in line crystals often penetrated by the topaz crystals, specular
iron and very rarely euclases of which only seven or eight were
found in the extraction of several kilograms of topazes. In the
other mines examined the conditions are essentially the same, the
presence of crystals of rutile being noted in one of them.

The topazes are generally of the well known yellow color
though it is not rare to find reddish ones; light green and
colorless crystals are also found, but very rarely. The relation
with the lithomarge is so intimate that layers of this substance
are often found penetrating the cleavage planes of tbe crystals.
Other crystals having the composition of topaz are brown and
opaque or with a slight yellow varnish on the surface, without
well defined cleavage, and pass into a bluish schist which occurs
in blocks in the mass of the unctuous schists.

The diamond appears to belong to the same geological horizon
as the topaz, accompanying in its distribution tbe quartzites or
so-called itacolumites. It has not been found in the immediate
vicinity of Ouro Preto but the diamond-bearing zone commences
about sixty kilometers north of that city and extends almost due
north for a long distance, following the divide between the waters
of the Sao Francisco and the coast rivers. The idea that the
quartzites or the itacolumites form the primitive formation of the
diamond is an old one and arose from the fact that these rocks
are the predominant ones in the diamond region, but neither the
gem nor its attendant minerals were seen by the early explorers
in their original position.

The origin of the diamond may be studied by means of the
accompanying minerals, which being more abundant can more
readily be traced to their place of origin. Of these, some may be
regarded as accidentally associated with the diamond, but others,
whose presence in the gem-bearing gravels is more constant, must
be regarded as true satellites. Among these last the minerals
containing titanium such as anatase, rutile, rutile pseudomorph
after anatase, and titaniferous iron hold the first place. To these
are to be added black tourmaline, hematite in the form of specular
iron and of octahedral crystals, magnetite in grains, and, in some
places, klaprothine, in others, platinum. All of these minerals,
with the exception of the last, have been found in the quartz veins
which are very abundant in the neighborhood of Diamantina,
cutting the quartzites and schists.

The diamond also occurs in quartzite near the city of Grao
Mogol, where mining was at one time carried on. A specimen of
this rock containing a diamond has long existed in the national
museum at Rio and two specimens have lately been obtained for
the collection of the School of Mines. The rock in these specimens
consists of irregular grains of quartz with flakes of mica or of the
green substance, and with embedded crystals among which is the
diamond.

Geology and Mineralogy. 225

In its lithological characters it resembles closely the upper
quartzite of the Serra de Itacolumi and probably belougs to the
same geological horizon!

Two theories may be proposed to account for the presence of
the diamond in this quartzite. One that the diamond already
existed when the rock was consolidated and thus entered into its
composition like any other pebble ; the other that the diamond
was formed in the rock. At first sight the first theory appears
the most probable one, but there are some reasons for giving
more credit to the secoud.

A third mode of occurrence was noted by Messrs. Heusser and
Claraz at Sao Joao da Chapada, near Diamantina, where the
diamond is associated with a white clay analogous to lithomarge
which occurs with veins of quartz containing specular iron, that
traverse the quartzites.

It will be seen, therefore, that the diamond and topaz are found
in the same rocks and geological position and with the same min-
eral associates.

The other colored minerals or gems of Minas, viz: the beryl,
chrysoberyl, spodumene, andalusite, garnet and red and green
tourmaline, occur in an older series of crystalline schists which is
formed to the east of the diamond-bearing zone in the basins of
the Jequitinhonha and Arassuahy. The rocks of this region
consist of gneiss and mica-schists which in places become graph-
itic. The gems occur principally in loose gravel but have been
traced to their original deposits in quartz veins traversing the
crystalline schists.

It is to be noted that of these minerals the tourmaline is also
associated with the diamond and topaz-bearing rocks, but in this
case it is always the black variety, not the red, green or white
varieties of the crystalline schists.

In concluding this brief abstract of the very interesting inves-
tigations of Prof. Gorceix, by far the most complete and serious
studies that have ever been made of the geology of Minas and the
mode of occurrence of the precious stones which have fendered
the province famous, we would say that for the most part his
conclusions are in complete accord with those of our countrymau,
Prof. O. A. Derby, who visited the diamond region last year and
who has now in press a memoir giving the results of his studies.
In the few minor points in which the two geologists are not in
accord further investigations are necessary, and we are pleased to
be able to state that the eminent geologist of Ouro Preto has just
undertaken a trip to the northern part of the province in which it
is to be hoped he will have the satisfaction of completing his
studies and of setting at rest the long disputed questions in
regard to that most interesting subject, the mode of origin and
occurrence of the diamond. — Editorial in Rio News, Rio de
Janeiro, May 24th.

226 Scientific Intelligence.

2. Progress of the Volcanic Eruption on Hawaii*

The great eruption of Mauna Loa has been flowing for about
eight months. The mighty mountain has poured forth from its
upper vents, near Mokuaweoweo, the summit crater, a river
of lava, about fifty miles long and varying from half a mile to
four miles in wi<Jth, which is now distant a few miles from
Hilo, threatening to destroy the town, to fill up the harbor, and
probably, as on a former occasion of eruption, invade the Pacific
ocean and add many thousand acres to the area of the Archipelago.
Whilst seeking for compensation in the view of a possible great
misfortune, it may be interesting to note, that whilst King Kala-
kaua is making the tour of the world, in order to bring more peo-
ple under his beneficent sway, the goddess Pele may be adding a
new appanage to His Majesty's dominions.

The latest reports from the eruption inform us that the great
lava flow that had reached within two miles of Hilo, had then
broadened its stream to a width of about four miles, and banked
it up in places to a height of over one hundred feet, and there
halted, like a beleaguering force, before making a final assault,
and storming the doomed city. Already it had sent off a skirm-
ishing stream, the narrow flow running down the gulch of Kukuau;
and should the great lava embankment burst forth along its front,
the destruction of Hilo would be swift and overwhelming, with
not a vestige upon the corrugated and wavy surface of black glass
and clinker to show that over the spot, the aspirations and spires
of a christian community once pointed to heaven.

We learn from recent visitors many interesting particulars in
regard to the present state of the great active crater, Kilauea,
which is distant about thirty miles from Hilo. Tourists to the
volcano, for many years past, all remember certain active pools of
lava, the North and South Lakes, which ordinarily bubbled and
tossed a fiery flood at a depth of about 120 feet below the floor of
the great crater; now these lakes have all been filled up, and
there have arisen peaks and cones of hard lava, that rise over one
hundred feet above the south bank of the great crater which is
about one thousand feet high. But there has burst forth a new
opening in the great crater floor, not far distant from the old
lakes, and a new lake, almost round in form, about six hundred
feet across and some seventy feet in depth in ordinary stages,
below the surrounding brink. Here the great Hawaiian volcano
presents the most varied fantastic play of liquid lava. The follow-
ing are some of the phases of the play of a fire lake, as recently
observed in the crater of Kilauea. Sometimes it almost seems
to sleep, and the disappointed visitor looks down into a black
valley and observes a smoking pit, giving no more evidence of
combustion than a tar kiln. It presents a daVk silver grey hue
with a satiny shine. This is a crust of quiescent lava; and
the observer who has expected to have his sense of wonder

* The earlier features of the eruption were announced iu the last volume of
tins Journal, on page 79, in a letter from Rev. T. Coan, of Hilo.

Qeology and Mineralogy. 227

strained to speechlessness, says: "Is this all?" But soon the
broad disk of the lake heaves and trembles. Now the moving
floor cracks and a serrated fissure, like the suture of a skull, runs
from side to side ; and quick darting streaks, sudden cracks
of the crust, shoot across in all directions. These serrated streaks
are, at first, rosy lines on the gray surface ; then they are wider,
like crimson ribbons, broadening to the view. Another crimson
fount springs up along the now fretting and roaring rim of the
lake. And another, and another of now wildly upleaping fount-
ains of fire toss high their ruddy crests, and thi*ow off gouts
and clots of red spray that fall and harden near the observer's
feet. By this time the spirit of our inferno is aroused. The
whole fierce red lake is all boil and leap and roar. It is more
than the roar of loud sea surfs beating bold bluffs. The surging
tide of the molten earth, sounds a deeper, bellowing bass than any
note of the sounding sea. Finally the heaved up crust broken
into fragments, is churned up and dissolved in the boiling flood.
The roaring gulf is now indeed a vortex of indescribable glories
and terrors.

And then the wild lake settles down to calm again or to a
milder display by and by; or perhaps simply upheaves, and
overflows its bounds and spreads abroad in the great crater. But
at all times it is wonderful, and is ready to satisfy the curious
observer that here in mid Pacific, in our Hawaiian islands, is the
grandest, most varied and most momentous volcanic action to be
seen on the surface of the globe. — Letter to the Commercial Ad-
vertiser■, Honolulu, July 30.

From a Letter of Rev. Titnx Coany dated Hilo, June 28. — For
a few days past our volcanic fires have been more vivid and glar-
ing than ever.

The northern wing of the line is less than six miles from us,
and the southeastern is less than five miles distant, while the
center of the line appears the most sanguinary. From the south-
east wing the lavas have fallen into a rough water channelxtwenty
to fifty feet wide, which comes down from the main bed of the
flow almost direct to Hilo, rrossing Volcano street, half a mile
from Mills' store and entering into the Waialama stream, which
cuts the beach about midway. In this way the lava at white
heat is fast approaching the shore. It is now only two and a half
miles from Volcano street, and it is very liquid, running much
like water. It has, some pait of the time, run at the rate of half
a mile a day.

I have been to the lava flow to-day (June 28th) and returned.
We found two streams of liquid lava coming down in rocky
channels which are sometimes filled with roaring waters, but
nearly dry at this time. These two gulches are too small to hold
the flowing lava, and the fiery flood overruns the banks, and
spreads out on either side. The united width of these streams
may vary from fifty to two hundred feet. In going down the
steeper parts of these rocky beds the roar is like that of the

228 Scientific Intelligence.

heavy surf on the coast, and often like thunder. — Hawaiian Ga-
zette, July 6.

Letter of D. H. Hitchcock, dated Hilo, June 30th, 1881. —
About Wednesday of last week, the old mountain was observed
to be more than usually active, the whole summit crevasse pour-
ing forth immense volumes of smoke. By Friday noon the three
southern arms had all joined into one, and rushing into a deep
but narrow gulch forced its way down the gulch in a rapid flow.
By Saturday noon it' had run a mile. On Monday morning it
was reported to have reached the flats, back of Halai Hills.
Monday afternoon we rode up to it before dark and found that
the stream was entirely confined to the gulch and intensely active.
It was than about half a mile from the flats spoken of.

The flow was on an average 75 feet wide and from 10 to 30
feet in depth, as it filled the gulch up level with its banks. The
sight was grand. The whole frontage was one mass of liquid
lava carrying on its surface huge cakes of partly cooled lava.
Soon after we reached it the flow reached a deep hole, some 10 or
15 feet in depth with perpendicular sides. The sight as it poured
over that fall in two cascades was magnificent. The flow was
then moving at the rate of about 75 feet an hour. About mid-
night we noticed a diminution in the activity of the gulch flow
and soon saw a bright red glare above the tree tops, and were
presently startled by the burning gas bursts and the crackling
and falling of the trees somewhere above us. The whole sky
above was lined with the light of burning trees and shrubs.
About 2 a. m. we made the attempt to reach the scene of the
great activity and succeeded by going up the south side of the
gulch some quarter of a mile. And what a scene lay before us as
we ascended a slight elevation. The on-coming overflow had
swept over the banks of the narrow gulch and was flowing like
water into a dense grove of neneleau and guava trees. There
they stood in a sea of liquid lava over a space of more than an
acre, while the fires were running up their trunks and burning
the branches and leaves overhead. The flow was so rapid that
the trees were not cut down, for more than 200 feet from the front
of the flow. In one place we saw a huge dome of half melted
lava rise up, 15 or 20 feet high, and twice that in diameter and
apparently remain stationary, while the fiery flood went on. —
Hawaiian Gazette, July 6.

Letter from Rev. Mr. Goan to Professor Ghester S. Lyman,
dated Hilo, July 21st, 1881. — By mail of to-day I send you the
Hawaiian Gazette of the 6th inst. In it you will see the state of
the lava flow of that date. Since then the southeast wing has
made fearful progress. I was at the lower end of the igneous
stream on the 18th inst. It was then about two miles from the
upper part of our town, making slow progress toward us. One
of our guests returned to us early this morning reporting that the
action of last night was very great, and that the movement .n
the outer cha net was, at one time, 60 feet in 19 minutes. He

Geology and Mineralogy. 229

thinks it is now only a mile from our town, and that it can be
reached .n 15 minutes. It now seems nearly sure that this
advance will reach us. Still we have hope.

It is now 8-J months since the outburst began near the summit
of the mountain. During this period it has sent out a vast stream
some 30 miles toward Mauna Kea; another of nearly equal
dimensions toward Kilauea. Between these streams others of
very liquid paihoehoe have divided and subdivided on the sides
of the mountain, on the plains below, and in the great forest
between the mountain and the sea. Some parts of the fiery line
are still operating in the woods about five miles distant, but the
southeastern wing has come through in force, and from this wing
the stream which now threatens us has advanced four miles from
the main body. Should its speed increase it will soon enter our
town in the channel which cuts the beach about in its center and
enter the harbor. But as the body of the fiery fusion is too
large to be confined to the water channel, it will probably spread
on both sides and thus consume many buildings.

It is amusing to see the children and even older people gathered
at the lower end of the flowT and along its margin, all eager to
collect specimens from the viscid streams, moulding with poles
the plastic mass, as the potter the clay, into various forms of cups,
vases, birds, fishes, etc. These are readily sold at various prices
to strangers.

3. Glacial drift on Mi. Ktaadn, Mahie. — From a paper by
C. E. Hamlin, published as No. 5 of vol. vii of the Bulletin
of the Museum of Comparative Zoology (vol. i of Geological
Series), entitled Observations upon the Physical Geography and
Geology of Mt. Ktaadn and the adjacent district, we cite the
following. —

Material interesting from its relation to the transportation of
drift, whatever may have been the agent that moved it from the
north, is not wanting upon Ktaadn. The two slides furnish the
chief amount of such material. * * * *

On the East Slide much less drift is found than on the other.
Outside of the slides, I have never found drift upon the flanks of
the mountain ; but it re-appears higher up, in very small amount
on the Table Land, but principally upon the northern summits,
sparsely strewn among the broken granite that covers them.
Neither on slides nor summits is the drift ever found in large
bowlders, but always as fragments of moderate size. On the
Southwest Slide a few masses were seen as heavy as a hundred
pounds each, but in general — always, upon the East Slide — the
pieces run from a few ounces up to twenty pounds in weight.
They were chiefly fragments of slates and sandstones, identical
with the strata of the country north and west, mingled with
pieces of metamorphic and trappean rocks, such as occur in place
for a few miles beyond the Ripogenus Carry.

The fragments of stratified rocks on the Southwest Slide very
generally include fossil shells, mainly Brachiopods, and always

230 Scientific Intelligence.

impressions or interior casts. Owing to the small size of the
enclosing masses — due to the fissile structure of the rocks — the
fossils ordinarily are much decayed, but occasional specimens are
obtained in fine condition. Among the scanty drift upon the
upper third of the Southwest Slide, I have never seen a fossil-
bearing stone. And upon those parts of the summits where drift
was found, only once was a fossil met with, — a solitary Brachiopod
impression on a ten-pound piece of sandstone, picked up on the
slope northward from West Peak to the Saddle, about 600 feet
below the top of the peak, or at an elevation of about 4,615 feet
above the sea. This is by far the highest point at which fossil-
iferous rocks have yet been found upon Ktaadn.*

All the facts in the case serve to indicate that the non-granitic
material found upon the mountain is a portion of the so-called
" northern drift," with the fact of whose distribution — not the
manner — we are here concerned. But we may and must suppose
that in the distribution the sides and summits of Ktaadn, as far
up at least as 4,600 feet, received deposits of drift more or less in
quantity.

4. Doleryte (trap) of the Triassio-Jurassic area of Eastern
North America. — Dr. G. W. Hawes, using Thoulet's method of
separating associated minerals, through their difference in specific
gravity, by means of a mixture of potassium iodide and mercury
iodide in solution, has investigated the composition of a specimen
of the doleryte (diabase as he names it) from Jersey City. When
the mixture reached the specific gravity 3, the magnetite and
augite of the finely pulverized rock, and some mixed grains, had
sunk to the bottom, and only feldspar, as the microscope
showed, remained at the top ; and when diminished to a specific
gravity of 2*69 (without any considerable portion further settling)
the feldspar portion " separated into two parts with such facility
as to plainly show that two minerals were present." In chemical
analyses of these parts by Dr. A. B. Howe, the two yielded :

Si02 A1203 Fe2Os MgO CaO NaaO KaO HaO

1. Over 2*69 52-84 28*62 152 0-46 11-81 2*38 0'86 1*06 =99*55

2. Under 269 .. 60'54 24*11 114 021 9-15 4*11 1*06 0:59 =100*97

After citing these analyses the author remarks : " It is therefore
plain that the feldspathic element in this rock is not any single
feldspar. One of the feldspars is very plainly labradorite, and
the other has the ratio of andesite. The two feldspars were dis-
tinguishable under the microscope, and the optical properties of

* Dr. De Laski's statement of the height (4,385 feet) at which he found fossils,
"well up toward the 'Horseback' ridge" (this Journal, III, iii, p. 27), and which
is quoted by Professor Dana in his Manual of Geology (editions 2d and 3d), is
founded upon a wrong estimate of the altitude of the mountain. He adopted the
one current for some years before Professor Fernald's remeasurement of the
elevation, which he made to be 5,215 feet. Now the elevation of the "Horse-
back" ridge, at a point directly up from the head of the East Slide-— D*\ De
Laski's route — is 4,109 feet. It was below this point, that De Laski found his
" upper fossils."

Geology and Mineralogy. 231

tbe grains offered do peculiarities to conflict with the above de-
termination."

This method of analysis, as Dr. Hawes is aware, has a source
of error in the fact that the grains of a fine-grained crystalline
rock will not altogether, and perhaps not generally, be wholly free
from admixture, owing to the adhesion and interpenetration of the
associated minerals, and feldspars especially are likely to be thus
blended ; hence, while the existence of at least two feldspars is
thus plainly proved, the analyses of the two parts can give only
approximate results, and so they are regarded by the author.

There is another source of uncertainty as regards the feldspars
of such a rock in the similarity of specific gravity of some of the
species. The range for the prominent kinds, excluding some .ex-
treme numbers, are as follows :

Orthoclase 250— 259 Andesite 2-65— 2*72

Albite 259— 2-63 Labradorite 2*66—2-72

Oligoclase 2-59—2-66 Anorthite 2-70—277

Anorthite from all its localities (with a rare exception), about
half of the varieties of Labradorite, and one-third of those of an-
desite, have the specific gravity 2*69 or above; the rest, below
2*69. The doubts that are thus introduced, chemical analysis can
in part remove.

Dr. Hawes continues as follows: "The analyses of the anor-
thite and augite that I picked from West Rock may be added,
and our knowledge of this diabase may be said to be quite com-
plete as regards the composition of the fresh rock. I will place
together the analyses of the rock and its other components. Pro-
fessor Genth's analyses, to which I have referred, is more complete
than any that I have made, since he determined the traces of
lithia, copper and sulphur. But his analysis was made on more
hydrous material ; therefore I will use my old analysis of West
Rock, New Haven,* because the analyzed material was very fresh,
bright and clear, and also illustrates the commonest variety of the
rock."

The following analyses are then cited from the article by him
just referred to :f

Si02 A1203 Fe203 FeO MnO MgO CaO

West Rock, New Haven.. 5178 12*79 3.59 825 044 763 10-70

Augite, West Rock 5071 355 15*30 0-81 13.63 13*35

Anorthite, West Rock ... 45-95 34-70 0-64 1-80 tr. 15-82

NaaO K20 TiOa P„06 Igu.

West Rock. New Haven.. 2-14 039 141 014 0-63 = 99*89

Augite, West Rock [148] , 1-17 =100 00

Anorthite, West Rock _. . 0-45 0'96 =10032

* This Journal, ix, 183, 187-5.

f In citing the analysis of anorthite from his former paper, several changes are
made: 15-82 is placed opposite MnO instead of CaO, evidently by a slip of the
pen. and this is corrected above; but, further, 1-80 is put opposite MgO, when it
is the amount of K20 in the original paper, and 0 45 is put opposite K^O and
Na20 together, when it is the amount of &aO in the original paper. No reason
for the latter changes is given, and it remains uncertain as to which is in error.

Am. Jour. Sci.— Third Series, Vol. XXII, No. 129.— September, 1881.
16

232 Scientific Intelligence.

Dr. Hawes next gives the result of a calculation by him of the
mineral constitution of the West Rock trap from the above ele-
ments, which is as follows :

"Anorthite 15*52, albite 22*16, potash feldspar 2*32, augite
54*47, titanic iron 2*68, magnetite 1*76, apatite 0*32, total 99-23."*

Dr. Hawes thus makes out that the feldspar of the Jersey City
trap consists of labradorite and feldspathic material having the
ratio of andesite ; while that of West Rock consists chiefly of
anorthite and albite.

This extraordinary result for the West Rock trap and its
so wide divergence from that for the Jersey City trap make it
important to consider carefully the details in the calculation. It
is the more marvellous since Mr. Hawes's analyses of the Jersey
City and West Rock traps, in his former paper, gave them very
nearly the same chemical constitution. We cite the analyses
together for comparison, along with another (from the same paper)
of a trap from Wintergreen Lake, which adjoins West Rock.

SiOa A1203 FeaOs FeO MnO MgO

1. Jersey City 53-13 13-74 108 9*10 0*43 8-58

2. West Rock 5178 14-20 3-59 8*25 0-44 7*63

3. Wintergreen Lake 5242 14*54 1*25 9*84 0*51 7*33

CaO Na20 K20 P205 Ign.

1. Jersey City :... 947 230 1-03 090 = 99*76

2. West Rock 10-70 2'14 039 0 14 0*63 =99-89

3. Wintergreen Lake 10*59 2*23 0-49 055 = 99*75

In Mr. Hawes's citation of the West Rock analysis (see above)
he deducts 1*41 from the alumina, reducing 14*20 to 12*79, on the
ground of the recent finding of this amount of titanic acid in it by
Dr. A. B. Howe; and if right in this, some similar deduction
would probably have to be made for the rock of the other local-
ities.

New analyses throughout would have afforded a surer basis for
a calculation. But even with these, a different treatment of the
facts would have been required for right conclusions.

Mr. Hawes says, in the paragraph cited above, after giving his
results from the Jersey City trap, that our knowledge of this rock
may be said to be quite complete after adding his analyses of the
anorthite and augite which he " picked from West Rock." But
anorthite found in a trap at West Rock, New Haven, and not in
the Jersey City rock (places eighty miles apart), has no bearing
on the composition of the latter, except by way of suggestion.

Further : the " auorthite in West Rock," of which he gives the
analysis, was not from the West Rock dike, and has no where
been detected in the West Rock trap, or in any other trap of the
various New Haven trap ridges (or as yet elsewhere in the Con-
necticut valley) except in a single dike that intersects the West
Rock ridge transversely and thence continues along the south side
of " Wintergreen Lake," and which is therefore of later origin.
The anorthite is in isolated crystals about three inches apart on

* The numbers for the anorthite and albite should be transposed.

Oeohgy and Mineralogy. 233

an average, thus making the rock very sparsely porphyritic ; and
Mr. Hawes in his former paper (in which the locality and rock
characteristics are rightly given) remarks that it crystallized out
from the mass of the rock because of its different composition ;
as he has since rightly observed, it was first to crystallize because
less fusible than the rest of the feldspar portion.*

The mass of the rock^ containing none of the anorthite crystals,
was analyzed by him separately and his results are those of No.
3 in the last table ; they show a very near identity with the West
Rock trap.

It appears, hence, that Dr. Hawes's recognition of anorthite as
a prominent ingredient of the West Rock trap was not warranted
by any observed facts ; that his announcement of albite as a
constituent has as yet nothing to sustain it ; and that the Mesozoic
trap of eastern North America still needs careful investigation.

J. D. D.

5. New Devonian Plants. — Dr. Dawson read before the Geo-
logical Society of London, June 23d, 1880, a paper describing sev-
eral new North American Devonian plants, as follows : A small
Tree-fern, Asteropteris Noveboracensis, characterized by an axial
cylinder composed of radiating vertical plates of scalariform tissue,
imbedded in parenchyma, and surrounded by an outer cylinder
penetrated with leaf-bundles with dumb-bell-shaped vascular bun-
dles, from the Upper Devonian of New York ; a species of Equi-
setites (E. Wrightianus), showing a hairy or bristly surface, and
sheaths of about twelve, short, acuminate leaves ; a specimen of
wood, new in its characters, from the Devonian of New York,
named Cellaloxylon primwvum, and having some analogies with
Prototaxites and with Aphyllum paradoxum of Unger ; also sev-
eral new ferns from the well-known Middle Devonian plant-beds
of St. John, New Brunswick, confirmatory of the previous con-
clusion as to the age of the beds, and showing the harmony of
their flora with that of the Devonian of New York, and also the
fact that the flora of the Middle and Upper Devonian was emi-
nently distinguished by the number and variety of its species of
ferns, both herbaceous and arborescent.

6. On Fossil Plants from the Lignite Tertiary Formation, at
Roches Perc'eeSy Souris Hivery Manitoba ; by Dr. J. W. Dawson.
(Canadian Naturalist, Jan., 1881). — Dr. Dawson states in his
paper that the Lignite Tertiary Group of Manitoba and elsewhere
in the Western Plains rests immediately on the Upper Cretaceous,
and holds extensive deposits of valuable lignite, associated with
shale and sandstone containing numerous remains of plants. This
flora resembles very closely in its aspect that of the Miocene
Tertiary of Europe, but there is reason to suspect that the whole
belongs to a period of transition between the Cretaceous and
Tertiary ages. The species of plants were collected by Mr.

* New Hampshire Geol. Reports, vol. iii, p. 92. He says, speaking of a similar
case in New Hampshire : The reason for the occurrence of the anorthite in large
isolated crystals is "that the anorthite is much less fusible ; hence in rocks cooled
from igneous fusion, the anorthite would crystallize first, and would have an
opportunity to form larger crystals in the still plastic mass."

234 Scientific Intelligence.

Selwyn, and includes the following: Leaves of a magnificent
Platanus or Sycamore, a foot or more in length and of propor-
tionate width, identical with P. nooilis of Newberry, from the
Tertiary beds of Fort Clarke on the Upper Missouri ; a species
of Sassafras, a genus not hitherto found in our Lignite Tertiary,
though represented in the Cretaceous and in modern times, dedi-
cated in the paper to Mr. Selwyn ; several Poplars, as Popuhis
arctica Heer, P. cuneata Newberry, P. acerifolia Newberry, a
Hazel, a chestnut-leaved Oak apparently new, some Coniferous
trees, as Sequoia Langsdorfii, an ally of the giant trees of Cali-
fornia, Taxodiurn occidentals, of Newberry, and Taxites Olriki
of Heer. The flora indicated is, on the whole, similar to that of
the Porcupine Creek group of Dr. G. M. Dawson's Report on the
49th Parallel, that of the Lignitic area of the Mackenzie River,
described by Heer as Miocene, that of the Fort Union group of
Newberry, and of the Carbon group of Lesquereux, — formations
variously regarded as Eocene or Lower Miocene, and very widely
distributed over the western plains. These plants will be fully
described in a forthcoming report of the Geological Survey, where
their affinities and geological relations will be discussed.

7. North American Mesozoic and Ccenozoic Geology and
Palaeontology, or an Abridged History of our knowledge of the
Triassic, Jurassic, Cretaceous and Tertiary Formations of this
Continent ; by S. A. Millek. 338 pp. 8vo. Cincinnati, 1881.
(Reprinted in volume form from the Journal of the Cincinnati
Society of Natural History.) — This volume is the result of much
labor. It contains a mention of a large part of the papers,
memoirs or works published in the country on the geological
formations mentioned in the title, with often citations of para-
graphs giving the views contained, and will be of much use to
geologists. The work is most complete paleontologically, as this
is the particular direction in which the author has labored. The
volume is not properly a history, but rather like a scrap-book in
the collection of its material. The arrangement under the grand
divisions is chronological ; but there is much mixing up of dates
and subjects under the Cenozoic, where the drift, Eocene, Miocene,
etc., come in variously; and references, as well as dates, are often
wanting throughout the work, or are insufficiently given. By
improving it in these respects and making it complete in its list
of papers, the author would increase greatly the value of the
volume. On one topic — that of the drift — the work departs very
widely from a history, and the references are much more defective
than elsewhere. He says that " he has undertaken to overthrow
the Glacial hypothesis." As his knowledge of the subject ex-
tends, he will probably reject many of his explanations, and come
out, like nearly all othera who have studied the subject, a good
Glacial i s t, though his objections to some of the views which he
makes part of the Glacier theory are likely to stand.

8. Species of Pterygotus from the Water -lime group near
Buffalo. — Mr. J. Poiilman has described in the Bulletin of the

Botany and Zoology. 235

Buffalo Society of Natural History, vol. iv, No. 1, 1881, the
maxilliped of Pterygotus Buffaloensis, from the Water-lime group
near Buffalo, with illustrations, the length 6£ inches and breadth
l£ ; and also, from the same beds, the new species, Ceratiocaris
grandis, the carapace measuring 9£ inches in width and 5£ in
length and having its surface finely granulose. The rock has
also afforded Eurypterus remipes, E. lacustris, E. robustus and E.
Dekayi. The author states that Eusarcus scorpionis of Grote
& Pitt is probably Hall's Euryptems pustulosus.

9. On the genus Alveolites, Amplexus and Zaphrentis, from
the Carboniferous System of Scotland ; by James Thomson,
F.G.S. Phil. Soc. of Glasgow, 1881. — This paper gives a review
of previous views as to the genus Alveolites and its relations to
Favosites and Chcetetes. It is stated to differ from the last two in
having fissi parous generation, while Favosites differs from Chcetetes
in the presence of mural pores. The paper is well illustrated by
many figures on four plates, representing details as to the corals
of 4 species of Alveolites, 6 of Amplexus, and 23 of Zaphrentis, of
which one species of Alveolites is first described by the author,
and 9 of Zaphrentis.

10. A Memoir upon Loxolophodon and TTintathsrium; by
Henry F. Osborn, Sc.D., with a Stratigraphical Report on the
Bridger Beds in the Washakie Basin, by John B. McMaster,
C.E. 54 pp., 4to, with 6 plates. Princeton, N. J., July, 1881. —
This paper is the commencement of a series of publications, in
large and handsome quarto form, under the title, " Contributions
from the E. M. Museum of Geology and Archaeology of the Col-
lege of New Jersey." The memoir treats of the distinction and
characteristics of the genera TJintatherium and Loxolophodon, and
describes the new species Loxolophodon Speirianum, besides giving
the characters of portions of the skeleton of TJ. Leidio.num, and
also, at greater length, of that of TJ. mirabile (which is the L>ino~
ceras mirabils of Marsh). The memoir is illustrated by six excel-
lent lithographic plates, one folded plate representing the skull of
L. Speirianum one-third the natural size; the second, the skull of
TJ. Leidianum; the third, teeth of Loxolophodon; the fourth,
restoration of Loxolophodon; the fifth, a map of the Eocene basin
of Wyoming Territory, and the sixth, sections through the Leclede
Bad Lands.

1 1 . Vanadinite in Arizona. — The followiug note to the editor,
from W. P. Blake, was received in a letter dated San Francisco,
June 14, 1881 : "Will you please note in the Journal that in a
letter to you I report the occurrence of vanadinite in the lead-
bearing veins of Castle Dome District, Arizona, associated with
wulfenite, cerussite, galena and fluor-spar."

III. Botany and Zoology.

1. DeCandolle, Monographim Phcenogamarum. Vol. III.
Paris, Masson, June, 1881, pp. 1008, tab. i-viii. — This ample vol-
ume has very promptly followed its predecessor, which contained

236 Scientific Intdligeiice.

the Aracece by Engler. This comprises four more Monoeotyle-
donous orders, and one Dicotyledonous, namely the Cucurbitacece.

The least important of the monocotyledonous orders is that of
the Philydracem, of only four Australian species (one of which is
also E. Indian), divided among three genera ! And one of those has
had three names or even four if we count an orthographical differ-
ence. The author is the accomplished Prof. Caruel late of Pisa,
now again of Florence, where he may be expected to do much
good work for our science.

The three following small orders, Alismacece, Butomacece, and
Jitncaginece are elaborated by M. Micheli of Geneva, who, in a
preface treats of the literature, structure and limitation of these
nearly related groups. Although for the present admitting all
three to ordinal rank, the author distinctly favors Bentham's
view, viz: that the second group should go with the Alismacece,
and the third be kept apart. And the singular genus Eilcea, he
would exclude as well from the Naidece as from all these orders
or groups, although he appends it to the Juncaginece. From
Alisma L. to Sagittaria there is such a succession of connecting
forms that it is very questionable how many, if any, generic divis-
ions should be maintained. But in order to sustain the Linnaean
fenera, Micheli adopts three intermediate ones (Limnophyton of
liquel, Elisma of Buchenau, and JEchinodonis of Richard) and
makes one new one (Lephiocarpus on Sagittaria calycina and
two S. American species), besides Damasminm, Juss., which is
well characterized by its biovulate carpels. This character is not
shared by the Californian species, which therefore is remanded to
Alisma, thus weakening the former, genus. Limnophyton con-
sists only of an African and Indian species, which was for Lin-
naeus a Sagittaria and for Willdenow an Alisma, the latter prefer-
able. Elisma (on Alisma natans L.) has a better-defined character
in its introrse micropyle. Echinodorus is at length worked up
into 17 species, two of them European, the rest American. All
of N. American species extend to the tropic and most of them to
Brazil. The forms of Sagittaria are arranged under 9 species, of
which we have six, and S. variabilis is restored to S. sagittmfolia.
The so-called campylotropy in most of these genera is the result
of a subsequent flexion of an anatropous ovule. Of the BtUoma-
ceo3it only need be remarked that Limnocharis (including Hydroo
leis) is referred to it. Of the Juncagineae it is to be noted that
the species of Triglochin have a very wide distribution, and that
T. triandra of Michaux, with several synonyms, is referred to 7!
striata of Ruiz and Pavon, as indeed had been made out by Buche-
nau and his predecessors. T. maritima is said to inhabit salt or
brackish swamps only. In North America it grows luxuriantly in
mountain bogs of perfect freshness.

The Commelinaceo3y by C. B. Clarke, fill over 200 pages and
are illustrated by eight lithographic plates, which are not very
well executed. The 307 known species are, with apparent good
judgment, ranked in three tribes, and under 26 genera, of which

Botany and Zoology. 237

the conspectus hardly exhibit8 the characters. The order is chiefly
tropical, but it, like several others, finds its most northern limits
in the Northern United States or British America. It is to be
hoped and expected that our few but troublesome species of Com-
melina are here well settled. Tinantia anomala is tbe new
name of Torrey's Tradescantia anomala of S. Texas. Tradescan-
tia pilosa (T. flexuosa, Raf.)is made a mere variety of T. Vir-
ginica. T. Vloridana of S. Watson is cited as a synonym of
T. gracilis, H. B. K. T. linearis, Benth. is in Wright's collections
from S. Texas. Tradescantia leiandra of Torrey is Commelina
leiandra of Clarke, while Torrey's var. brevifolia is Zebrina ? lei-
andra of the same.

The Cucurbitacem, ably monographed by Cogniaux of Belgium,
occupy two-thirds of the present volume. It is more than fifty
years since this important order was elaborated for the Prodro-
mus by Seringe, upon a tenth part of the materials now in hand.
Naudin has in later years admirably elucidated a considerable
number of genera, mostly upon the living plants, and sketched
some of the grouping. But the full study and proper charac-
terization of the tribes and genera, as now known to science, was
the work of Sir Joseph Hooker, in the first volume of the Genera
Plantarura, published in 1867, a work which receives (as it well
deserves) high praise from the present monographer. Indeed,
the classification of the Genera Plantarum is completely adopted ;
and the changes in the limitation of genera are wonderfully few
and slight, considering the wealth of species and of hitherto
unexamined materials which M. Cogniaux has had in hand. So
completely have the extant materials been brought together, or
otherwise examined, that the author is able to declare that there
are only eight out of the 600 species now described which he has
not seen; and also that over one-third of them (219) have been
first described by him, either in the present monograph or in his
recent anterior publications. Such faithful and conscientious work
cannot be too much lauded and commended as an example. In
the prefatory portion the various mooted questions respecting the
morphology of the tendrils, inflorescence, andrcecium and fruit of
the order, are referred to rather than discussed ; but the whole
bibliography is indicated in a foot note. Upon the androecium the
author does express an opinion, and upon good grounds. The
crucial instance is really furnished by the genus Feuillea, which
has the full number of five stamens, wholly separate, and alter-
nate with the petals. If their anthers were really bilocular, as
Hooker in the Genera Plantarum took them to be, then it would
probably be correct to say that the ordinary Cucurbitaceso have
2£ stameus, i. e. two with bilocular and one with an unilocular
anthers. If, on the contrary, these normal five are unilocular, we
must conclude, with Payer and Baillon, that unilocularity is the
type of the order, and that old notion is correct, namely: that the
apparent three stamens are really five, four of them united in
pairs, and orie separate. Now Cogniaux is perfectly right in the

238 Scientific Intelligence.

statement that the anthers of FeiiiUea are unilocular, although
biloceUate. Indeed, Hooker had subsequently ascertained this in
the case of F. Moorei, figured in the Botanical Magazine, although
he does not there generalize the observation. This being the
case, the older view must be preferred. And being preferred by
Cogniaux, it would have been better to have adopted it practi-
cally as well as theoretically, and constructed the generic char-
acters accordingly, instead of on the old model of "Stamina 3,
anthera una uniloculars, caeterae bilocularis" more convenient
though it be.

The geographical distribution of a family at once so peculiar,
so wide-spread and so considerable in numbers and generic diver-
sity (79 genera and 600 species), might raise interesting specula-
tions. It must be an ancient family ; for the numerous genera,
as well as the species, are circumscribed in range, and only six or
seven are common to the Old and New World, except as diffused
under human agency.

We note one generic name to be changed, not because of the
somewhat bizarre fancy of Mr. C. B. Clarke in naming two genera
of the same order in honor of the same person, i. e., Warea and
Edgaria, but because the Cruciferous genus Wdrea, always of
unquestioned validity, has held its place in all the books from
landley's Vegetable Kingdom down to the new Genera Plan-
tarum inclusive. The latter work is followed in the reference of
Megarrhiza to Echinocystis, as proposed by Decaisne, although
meanwhile the singular germination has been made known, con-
firming our opinion that the genus is a thoroughly good one.
Changes in the nomenclature of our scanty North American
Cucurbitacete are few. Cucurbita perennis is identified with the
Mexican C. fo?tidi*sima, H. B. K. We should say that this and
the related perennial species are provided with fleshy roots, not
with "rhizomato crasso" Sicydium of Schlechtendal having
been identified with Triceratia of A. Richard, and the genus
rehabilitated, the Texan Sicydium of Gray and £ngelmann be-
comes the type of a new genus, which is dedicated to that capital
botanist, Maximowicz. & Lindheimeri is therefore Jfaximowiczia
Lindheimeri^ Trianosperma becomes a section of an older genus
Cayaponia of Mauso, and our species is accordingly (7. Boykinii,
Cogn. Xaudin's Echinopepon is by Cogniaux also absorbed into
Echinocystis (which we should restrict to the original species),
and so the Etatcrium Cotdteri, E. Wrightii, etc., are here trans-
ferred to the first section of the latter genus. The West Indian
Sicyos laciniatt(8y L., takes in & parrifiorus^ Gray, not Willd., nor
Kunth.

All the numbers of distribution of specimens which are cited in
the volume are specially indexed at its close under the collectors'
names, alphabetically arranged, — a great convenience. a. g.

2. Arboretum Segrezianum : Ieones Selects* Arborum et Eru-
ticum in Hortis Segrezianis Collectorum, etc.; par Alphonse
Lavaixee, President de la Societe Xationale d' Agriculture de
France, «fcc. — The collection of trees and shrubs at Segrez (a few

Botany and Zoology. 239

leagues from Paris), although of comparatively recent foundation
by a single individual at his country place, is already an impor-
tant establishment, and in hardy shrubs it is wholly unrivalled.
The shrubs are not only collected, but critically studied. The
valuable catalogue published a few years ago gave evidence of
this. And now, in this more sumptuous work, critical, little-
known, or new species are admirably figured, fully described, and
their history and synonymy discussed with ability. Two volumes
of 60 plates each are promised ; three fascicles have already ap-
peared (the first in 1880, the third early in the present summer),
each of six plates and a sheet of letter-press, in imperial quarto
form. The plates are engraved on copper from drawings by
Riocreux and by one or two other artists of hardly less excel-
lence ; and all the main details of flower and fruit are given in
the analysis. The pomaceous or other fleshy fruits are colored.
Altogether this is a work of note and of the highest value, is
evidently a labor of love and of pure scientific devotion. It is
published by J. B. Bailliere at Paris, etc., at the price of ten
francs per part of six plates. Thus far most of the species illus-
trated are either North American or of North-eastern Asia, and
therefore of special interest to us. The American species are as
follows: Jamesia Americana, Diervilla sessilifolia, NuttaUia
cerasiformis, Crataegus punctata. a. g.

3. Ths British Moss- Flow / by R. Braithwaite, M.D., F.L.S.
Part iv. Fam. v, Fissidentacem. — This continuation of the excel-
lent work which we have already noticed includes pp. 64-82, and
plates 10-12, and illustrates 13 British species of Fissidens. The
plates are admirable. One of the species is F. ventricosus of
Lesquereux, figured in the supplement to Sullivant's Icones, and
here referred to the European F rufulus of Schimper. a. g.

4. Butterflies, their Structure, Changes and Life-histories with
special reference to American Forms ; being an Application of
the " Doctrine of Descent" to the study of Butterflies, with an
Appendix of Practical Instructions ; by Samuel H. Scudder.
322 pp. 8vo. New York, 1881. (Henry Holt & Co.).— This
beautiful volume is popular in its style and its many excellent illus-
trations, and scientific thoroughout, also. Biology has no stranger
or more interesting facts than those connected with the structure,
development and habits of butterflies ; and this is made strikingly
apparent by the descriptions in Mr. Scudder's well-written and
attractive work. The various topics discussed — the egg, cater-
pillar, chrysalis, full-developed butterfly, and the various steps in
the process of transformation, their food and modes of taking it,
their neat-raaking, and their seasonal and regional variations and
other varyings unaccounted for, which seem to look toward new
species, their geographical distribution and their colonization in
New England — these and other subjects are illustrated almost
exclusively by reference to American butterflies. The Appendix
contains instruction for collecting, rearing, preserving and study-
ing butterflies, besides a list of the species mentioned in the text
and of the food plants.

240 Miscellaneous InleUigenoe.

IV. Miscellaneous Scientific Intelligence.

1. Meeting of the American Association for the Advancement
of Science* at Cincinnati^ Ohio. — The thirtieth meeting of the
American Association opened at Cincinnati on Wednesday, the
1 7th of August, under the presidency of Professor George J.
Brush, of New Haven, and closed on the Tuesday following.
Excellent arrangements had been made bv the Local Committee
for the meeting and for the various conveniences of the members.
One of the features thus supplied was the connecting of the
rooms of the several Sections with one another by telephones,
whereby the papers in progress in one Section were announced on
bulletin boards in the others.

The meeting was unusually large in its attendance and every
way successful. A list of the papers accepted for reading is giveu
beyond. An able address, illustrated with lantern views, was
given Wednesday evening, by Captain C. E. Dutton, on the
excavation of the Grand Canyon of the Colorado, from his own
explorations of the region. A resolution, laid over from the
preceding meeting as required by the constitution, was adopted,
dividing the association into eight sections : A. Mathematics and
Astronomy; B, Physics; C, Chemistry and its applications; -J,
Mechanical Science ; E, Geology and Geography ; F, Biology ;
G, Histology and Microscopy ; H, Anthropology ; I, Economic
Science and Statistics ; but giving power to the Standing Com-
mittee to consolidate any two or more sections, whenever deemed
advisable.

The liberality of the citizens of Cincinnati contributed largely
to the pleasures of the week, and it followed the members after
its close by arrangements for excursions on Wednesday and Thurs-
day : one to the Mammoth Cave, Kentucky ; another to Chat-
tanooga and Lookout Mountain (335 miles) ; and a third, for the
anthropological section, to the prehistoric cemetery at Madison-
ville where excavations have been made.

Montreal was made the next place of meeting, and the 23d of
August the time. Dr. J. W. Dawson, of Montreal, was appointed
President for the meeting:. The other officers elected are the
following :

Permanent Secretary: F. W. Putnam (continued). General
Secretary : Wm. Saunders, London, Ontario. Assistant General
Secretary: Professor J. R. Eastman, Washington. Treasurer:
William S. Vaux, Philadelphia (continued).

Vice Presidents: Prof. Wm. Harkness, Washington, Section
A ; Prof. T. C. Mendenhall, Columbus, Ohio, Section fi ; Prof.
A. C. Bolton, Hartford, Connecticut, Section C ; Prof. Wm. P.
Trowbridge, New Haven, Connecticut, Section D ; Prof. E. T.
Cox, San Francisco, California, Section E; Prof. W. H. Dow,
Washington, Section F ; Prof. A. II. Tuttle, Columbus, Section
G ; Proi*. D. Wilson, Toronto, Section H ; Prof. E. B. Elliott,
Washington, Section I.

Miscellaneous Intelligence 241

Secretaries : Section A, Prof. H. T. Eddy, Cincinnati ; B, Prof.
C. S. Hastings, Baltimore ; C, Dr. A. Springer, Cincinnati ; D,
Dr. C. P. Dudley, Altoona, Pa. ; E, Capt. E. C. Dutton, Wash-
ington; F, Dr. C. S. Minot, Boston ; G, R. Brown, Jr., Cincin-
nati ; H, Prof. Otis T. Mason, Washington ; I, Dr. Franklin B.
Hough, Lowville, N. Y.

Prof. W. B. Rogers was elected the first Houorary Fellow of
the Association.

List of Papers accepted for Reading,

1. Astronomy, Mathematics and Physics.

D. P. Todd : Note on a comparison of Newcomb's tables of Uranus and Nep-
tune, with those of the same planets by LeVerrier.

Wm. HarknEss : On the methods of determining the solar parallax, with spe-
cial reference to the coming transit of Venus ; On a simple method of measuring
faint spectra.

M. Baker: Alhazen's problem: its history and bibliography, together with
various solutions of it.

H. A. Newton : Numbers of cometary orbits relative to perihelion distance.

J. R. Eastman : Method of determining the value of the solar parallax from
meridian observations of Mars.

A. W. Brown : The saroscope ; A register of eclipses traced from 3939 B. C.

S. S. Parsons: Electricity, magnetism, gravitation — their phenomena cou side red
as the manifestations of one force.

J. D. Warner : Scheme for aiding the memory of Euler's transformations of
coordinates.

P. E. Chase : Universal energy of light.

E. B. Elliott : On standard time.

W. W. Payne : Time service, Carleton College Observatory.

J. D. Warner : Symmetrical method of elimination in simple equations, by the
use of some of the principles of determinants.

S. J. Wallace: On an abbreviation in writing, a long series of figures, and its
use in calculations ; Cn a sign of logical connection in equations.

E. L. Nichols : On the electrical resistance and the coeficient of expansion of
incandescent platinum.

H. T. Eddy : A preliminary investigation of the two causes of lateral deviation
of spherical projectiles, based on the kinetic theory of gases ; Note on the theory
of flight of elongated projectiles ; On the mechanical principles involved in the
flight of the boomerang ; On a new method of applying water power of small head
to effect the direct compression of air to any required high pressure.

S. Marsden : Experiments to determine the comparative strength of globes and
cylinders of the same diameter.

W. LeConte Stevens : An improved sonometer ; The stereoscope, and vision
by optic divergence.

T. 0. Mendenhall: On the wave-lengths of the principal lines of the solar
spectrum ; Note on an experimental determination of the value of n ; Remarks
upon and an exhibition of Japanese magic mirrors.

J. R. Paddock : A new self-registering mirror barometer.

J. Lawrence Smith : The needle telephone, (a new instrument by Dr. Good-
man, of Louisville, Ky.) ; An anomalous magnetic property of a specimen of iron ;
Nodular concretions in meteoric iron, bearing on the origin of same.

A. G. Bell : Upon a new form of electric probe : Upon the use of the induc-
tion balance as a means of determining the location of leaden bullets imbedded in
the human body.

R. H. Thurston: On the effect of prolonged stress upon the strain in timber.

J. E. Hilgard: On recent deep-sea soundings in the Gulf of Mexico and
Caribbean Sea, by the U. S. Coast Survey.

5\ E. Nipher : Magnetic Survey of Missouri.

242 Miscellaneous Intelligence,

6. W. Hollet : Suggestions for improvement in the manufacture of glass, and
new methods for the construction of large telescopic lenses.

E. L. Sturteyaxt: Four years observation with a Lysimeter, at Farmington,
Mass.

L. Waldo : A new theory of the formation of hail ; On the errors to which
self-registering clinical thermometers are liable.

H. C. Hovet : A remakable case of retention of heat by the earth.

0. Stone : On the great outburst in Comet b, 1881. observed at the Cincinnati
Observatory.

Wm. Boyd : A musical local telegraph alphabet

T. Bassxett : Numerical elements of the orbits of the seven electrical vortices,
to whose motions atmospheric storms are principally due.

T. Stebry Hunt : Historic notes on cosmic physiology.

H. Cabmichael: A new radiomotor; A new differential thermometer.

2. Chemistry.

H. W. Wiley: Amylose; its nature and methods of analysis; Relation of
reducing power as measured by Fehling's solution to the rotatory power of
glucose and grape-sugar (amylose) ; Mixed or new process sugar, with methods
and results of analyses.

J. Lawrence Smith : Determination of phosphorus in iron ; Regulator of filter
pumps ; Iron with anomalous chemical properties ; Hiddenite, a new American
gem.

C. Richardson : The nitrogenous constituents of grasses.

W. 0. Atwateb: Chemistry of fish and invertebrates; Quantitative ^estimation
of nitrogen ; Quantitative estimation of chlorine; Sources of the nitrogen of plants.

A. B. Prescott : The limited biological importance of synthetic achievements
in organic chemistry ; Notes in experimental chemistry.

R. B. Warder: Evidence of atomic motion within molecules in liquids as
based upon the speed of chemical action.

A. Spingeb: Pentachloramyl formate.

C. F. Mabery and Rachel Lloyd: Dibromiodacrylic and chlorbromiodacrylic
acid.

Mrs. A. B. Blackwell: Constitution of the "Atom" of science.

Miss V. K. Bowers : Is the law of repetition the dynamic law underlying the
science of chemistry?

C. F. Mabery and H. C. Weber: On chlortribrompropionic acid.

H. B. Parsons : Composition and quality of American wines.

C. W. Dabney, Jr. : An iso-picraminic acid.

II. C. Hovey : Coal dust as an element of danger in mining.

Fr. A. Roeder : An attachment for burettes, avoiding the necessity of using
glass stop-cocks ; On a new form of balances.

II. Carmichael: A filtration evaporation balance; The liquefaction of glass in
contact with water at 250°.

G. C. Caldwell : Some new forms of apparatus for the chemical laboratory.

P. Collier : Development of sugars in maize and sorghums.

S. W. Robinson : Ringing fences.

3. Geology and Natwral History.

E. W. Claypole : The evidence from the drift of Ohio in regard to the origin
of Lake Erie ; On the discovery of an Archimediform Fenestellid iu the Upper
Silurian rocks of Ohio.

S. W. Trobridge : Remarks on the classification and distribution of Producti.

Wm. H. Ballou : Natural and industrial history of the White pine in Michigan;
Niagara River, its carton, depth, and wear.

Wm. McAdams : Fossil teeth of mammals from the drift of Illinois ; The occur-
rence of Cretaceous fossils near mouth of Illinois River.

H. Carmichael: The temperature of North German traps at the time of their
extrusion.

Miscellaneous Intelligence. 243

W. J. MoGee : A contribution to CrolTs theory of secular climatal changes.

H. S. Williams : The recurrence of faunas in the Devonian rocks of New York ;
On some fish remains from the Upper Devonian of New York.

R. Owen : The unification of geological nomenclature.

Edw. S. Morse : On changes in Mya and Lunatia since the deposition of the
New England shell-heaps.

J. W. Dawson : On Ptilophyton and associated fossils from the Chemung
Shales of Ithaca, N. Y.

E. Obton : The Berea Grit of Ohio.

N. H. "Winchell : Typical thin sections of the rocks of the cupriferous series
in Minnesota.

G. C. Swallow : Ozark Highlands.

G. Sutton : Gold-bearing drift of Iudiana.

J. W. Spencer : Features of the region of Lower Great Lakes, during the Great
River age : or notes on the origin of the great lakes of North America.

Wm. Bross: Canons, with some thoughts as to their origin.

H. Allen : Revision of the anatomy of the ethmoid bone in the Mammalia.

C. F. Gissleb: On Bopyrus Manhattensis from the gill-cavity of Palcemonetes
vulgaris Stimpson.

B. G. Wilder : On a mesal cusp of the deciduous mandibular canine of the
domestic cat, Felis domestica.

H. D. Schmidt : On the influence of the structure of the nerve-fibres upon the
production and conduction of nerve-force.

C. S. Minot : Note on the segmentation of the vertebrate body ; Note on
whether man is the highest animal ; Relations of the growth, size and age of
animals.

A. J. Howe : Digital differentiation.

Wm. Zimmerman : Recent existence of sword-fish, shark, and dolphin in the
fresh water pond near Buffalo, N. Y.

Si A. Forbes : On some relation of birds and insects.

Wm. H. Brewer : On the disposition of color-markings of domestic animals.

Mrs. L. Stone : Notice of a fern indiginous to California, but heretofore con-
sidered as an introduced hot-house spe'cies.

C. E. R idler : Some needed reforms in the use of botanical terms.

D. P. Penhallow : Phenomena of growth in plants.

W. J. Beal : The motion of roots in germinating Indian corn.
T. Meehan : Additional facts on the fertilization of Yucca.

B. D. Halsted : The lift unit in plants.

C. E. Dutton : Cause of the arid climate of the far West.

H. C. Hovey : Recent discoveries, measurements, and temperature observations
made in Mammoth Cave, Ky.

D. W. Prentiss: On the action of Pilocarpin in changing the color of the
human hair.

G. C. Swallow : Natural filtration of water for domestic use in cities.

E. S. Edmunds : Evolution and its place in geology.

D. D. Thomson : Influence of forests on streams.

4. Entomology and Microscopy.

E. W. Claypole : Life-history of the Buckeye stem -borer.

C. V. Riley : Retarded development in Insects; New insects injurious to
American agriculture ; The egg-case of Hydrophilus triangularis ; On the Oppo-
sition of Prodoxus decipiens ; The cocoon of Gyrinus.

W. H. Edwards : On certain habits of Heliconia charitonia ; On the length of
life of butterflies ; On an alleged abnormal peculiarity in the history of Argynnis
Myrina.

J. A. Lintner: On the life duration of the Heterocera (moths); A remarkable
invasion of northern New York by a Pyralid insect — Crarribus vulgivageUus.

A. J. Cook: How does the bee extend its tongue; The Syrian bees; Carbolic
acid as a preventive of insect ravages.

B. P. Mann : Suggestions of cooperation in furthering the study of entomology.
T. Taylor : New freezing microtome ; Bacteria and micrococci, and their rela-
tions to plant culture.

244 Miscellaneous Intelligence.

G. M. Sternberg : Contribution to the study of Bacterial organisms commonly
found on exposed mucous surfaces in the alimentary canal of healthy individuals.

L. Curtis : A study of blood during a protracted fast.

Wm. A. Rogers and G. P. Ballou : On a convenient method of expressing
micrometrically the relation between English and metric units of length on the
same scales.

C. S. Minor : The best method of mounting whole chick embryos.

Robt. Brown, Jr. : On a convenient form of slide case (with specimen).

J. D. Cox : Some phenomena in the conjugation of the infusorium Actinophrys
sol

6. Anthropology.

0. T. Mason : The uncivilized mind in the presence of higher phases of civiliza-
tion.

H. Hale : A lawgiver of the Stone Age.

W. C. Holbrook : Mound-builders' skeletons ; Prehistoric hieroglyphics ; Stone
implements in the drift.

Wm. McAdams : The stone images and idols of the mound-builders ; Remark-
able relics from mounds in Illinois ; Stone implement showing glacier marks.

W. H. Dall : On the inhabitants of N. E. Siberia, commonly called Chukchis
and Namollo.

J. G. Henderson : Houses of the ancient inhabitants of the Mississippi Valley ;
Was the antelope hunted by the Indians on the prairies of Illinois ? Ilex cassine,
the black drink of the Southern Indians; Agriculture and agricultural implements
of the ancient inhabitants of the Mississippi Valley.

Mrs. Erminnie A. Smith : Comparative differences in the Iroquois group of
Dialects ; Animal myths of the Iroquois.

E. S. Morse : On the ancient Japanese bronze bells ; On worked shells in New
England shell-heaps.

W. J. Hoffman : Interpretation of pictographs by the application of gesture-
signs.

S. H. Trowbridge: Exhibition of archaeological specimens from Missouri.

C. Thomas: On worked shells in New England shell-heaps; Comparison of
Maya dates with those of the Christian era.

A. S. Gatschet : Phonetics of the KayowS language.

W. De Haas: The mound-builders — an inquiry into their assumed southern
origin ; Antiquity of mau in America ; Progress of archaeological research.

S. D. Peet: Buffalo drives on the* Rock River in Wisconsin; The emblematic
mounds on the four lakes of Wisconsin.

P. W. Laxgdon: The temporal process of the malar bone in the ancient
human crania from Madisonville. .

2. /Science Observer and a cipher-code for Astronomical tele-
graphic messages. — The Science Observer, published by the Boston
Scientific Society, under the immediate editorship of J. Ritchie,
Jr., and devoted to the publication of Astronomical news, and
especially whatever is of immediate importance to the working
Astronomer, contains, in its last issue (Nos. 9 and 10 of vol. iii),
a paper by S. C. Chandler and Mr. Ritchie on a new form of
writing telegraphic messages for transmitting astronomical data.
The. method makes it possible to send messages containing astro-
nomical detail, such as the elements and ephemeris of a comet,
without any danger of error. A dictionary is used in making out
the code-cipher — W orcester's Comprehensive Dictionary, edition
of 1876. This book contains 390 pages, with over 100 words to a
page ; consequently, any integral number, up to 39,000, can be
represented by a word ; for example: 16,718, by the 18th word on
page 167, which is electrize; 349° 12', by the 12th word on page

Miscellaneous Intelligence. ' 245

349, which is proportionableness ; April 14d 10h 48m (== April
14d*45,= 134*45 day of the year (or 135*45, on leap year)), by the
45th word on page 134, which is crush, and so on. In a similar
manner each position of an ephemeris can be represented by two
words, one for the right ascension and one for the north polar
distance, which is to be preferred to declination, as the distinction
of pins and minus is thereby avoided. We refer to the article for
the details of the plan by which it is adapted to all the requirements
of general astronomical work. It has already been put into use be-
tween Boston and the Dun Echt Observatory. For one example:
The elements and ephemeris of Comet (b) 1 881, computed at Boston,
were communicated to Lord Crawford, at Dun Echt, in the words
— elegy pyrrhic linger armillary bnss illiteracy needy calmness
supervention chary stonework comprehensibleness staggard curse
spondaical confest diapente. The word illiteracy was a control
word, introduced to show whether the elements had been correctly
received. It is the word in the dictionary which corresponds to
one-fourth of the sum of the numbers expressing the elements, —
:i fourth being taken so that "the number may be always within
the limit of a 400-page book." The publisher of the Science
Observer announces that he will supply copies of the paper con-
taining all the details as to the code-cipher, printed on heavy
paper for observatory use, for 25 cents each, and will send a copy
of the Dictionary, post paid, for $1.25.

The last number of the Science Observer contains also Elements
and Ephemeris of Comet (b) 1881, and a report of observations
on the same comet, by O. C. Wendell, assistant at Harvard Col-
lege Observatory; Elements and Ephemeris of Comet (c) 1881,
from the Harvard and other observatories, with other Astro-
nomical intelligence. The Science observer is published at the
low price of 50 cents for twelve numbers, which make a volume.

3. A Dictionary of the Exact Sciences, Biographical and
Literary; by J. C. Poggendorff — continued and completed. —
Dr. W. Feddersen, of Leipzig, is preparing a supplement to
Poggendorff's well-known biographical dictionary. Many of our
readers will receive during the next few days circulars asking
them to answer a few questions as to their scientific life and
labors. As the great utility of such a work lies in the complete-
ness of the information it supplies, it is to be hoped that all
appealed to will send full answers to the questions, allowing
neither false modesty nor carelessness to cause a failure.

4. Report of the Cotton Production of the State of Louisiana,
with a discussion of the general Agricultural features of the State,
beiug an extra Census Bulletin ; by Eugkne W. Hilgard, Prof.
Agric. Univ. of California. 100 pp., 4to. Washington, 1881. —
Professor Hilgard's geological explorations of the States of Mis-
sissippi and Louisiana, and his study at the same time of their
agricultural resources, have eminently fitted him for the work he
is doing with reference to cotton production for the Census
Reports. The report just issued reviews first, by means of tables,

246 Miscellaneous Intelligence.

the amount of production of the leading crops in Louisiana ; and
then gives a brief outline of the physical geography of the State ;
a description of the great alluvial plain of the Mississippi, and of
the agricultural regions of the State, together with analyses of
soils and a discussion of the same ; separate agricultural descrip-
tions of the several parishes under the heads of the agricultural
regions to which they belong ; and, lastly, information as to agri-
cultural practice in the several parishes, obtained as replies to a
series of questions under various headings; these replies afford
data for a comparison of the different parts of the State, as
regards these several points. The questions relate to depth of
tillage ; the draft used in breaking up ; the practice of subsoiling ;
fall plowing or not ; rotation of crops or not, and if so, the order,
and the results ; kinds of fertilizers, and the results ; use made of
cotton seed, and its price; preparation of cotton land before
bedding up ; planting time ; planting in ridges or not ; variety
of seed preferred ; amount of seed per acre ; what implements ;
what after-cultivation ; time of first blooms ; time of picking ; and
so on, followed by other questions with reference to ginning,
baling and shipping ; diseases, insect enemies ; labor and system
of farming; wages, etc. The report shows that the great subject
of cotton production could not be in better hands.

5. Third Bressa Prize, Academy of Turin, open to Scientists
and Inventors of all Nations. — The value of the Bressa prize is
12,000 francs. The third prize is to be given to the person, of
whatever nationality, not a member of the Academy, who, during
the four years 1879-1882, shall have made, in the judgment of
the Academy of Sciences of Turin, the most useful or most bril-
liant discovery, or shall have produced the most able work, in
the physical and experimental sciences, natural history, pure and
applied mathematics, chemistry, physiology and pathology, with-
out excluding geology, history, geography and statistics.

Las Familias mas importantes del Reino Vegetal, especialmente las que son de
interes en la Medecina, la Agricultura e Industria, o que estan representados en
la Venezuela; por A. Ernst. 80 pp., 8vo. Caracas. 1881.

Second Report of the U. S. Entomological Commission fop the years 1878 and
1879, relating to the Rocky Mountain Locust and the Western Cricket, by C. V.
Riley, A. S. Packard, Jr., and C. Thomas, xviii, 322 and [80] pages, with many
maps and plates.

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THE

AMERICAN JOURNAL OF SCIENCE.

[THIRD SERIES.]

-•-•-♦-

Art. XXXV. — On the Cause of the Arid Climate of the Western
portion of the United States; by Captain C. E. Dutton,
TJ. S. A., U. S. Geological Survey.

Read before Section B, American Association for the Advancement of Science,

Cincinnati Meeting, Aug. 18th, 1881.

•

Many questions arising in the study of western geology
involve the consideration of the arid climate of the region, and
I have frequently been led to inquire as to its cause. Arid
climates are usually attributed to the passage of prevailing
winds over high mountain chains. As they ascend the moun-
tains upon the windward sides they are cooled by the expan-
sion due to diminished barometric pressure, their capacity for
moisture is reduced and an abundant precipitation takes place.
Descending upon the leeward sides these changes are reversed ;
the air is heated, its capacity for moisture is increased, it
becomes dry, and having been depleted of moisture is supposed
to be incapable of yielding a copious supply to regions beyond.
This explanation is no doubt good for some localities. Peru
is a case in point and for that country it seems quite perfect.
It is believed by many that it also explains the arid climate of
the western half of the United States, and that the Sierra
Nevada is the range which robs the winds of that region of
the moisture which otherwise would make its vast expanse
fertile. Reflection upon this case has led me to a different
conclusion.

It is unquestionable that the Sierra Nevada abstracts a

notable amount of moisture from the winds blowing from the

Am. Joub. Sci.— Third Series, Vol. XXII, No. 130.— October, 1881.
17

248 0. E. Button— Arid Climate of the Western U. S.

Pacific. Mr. B. B. Bedding, the Land Agent of the Central
Pacific Bailroad, has kept for several years excellent records of
the rainfall at many stations in California and Nevada, and
informs me that along the main road from Sacramento to the
summit pass of the Sierra, the annual rainfall increases at the
rate of one inch for every one hundred feet of altitude. At the
summit the mean annual precipitation exceeds ninety inches.
It is not improbable that this large amount is considerably
exceeded at numerous points along the crest of the range.
It seems clear therefore that the winds which blow over the
Sierra are to some notable extent depleted of moisture and the
effect must be to at least aggravate the aridity of the regions
lying immediately east of the range. But I think it can be
made evident that this effect is relatively not great, and that
the elevated region of the west would be on the whole very
nearly as arid as it now is if the Sierra Nevada were obliterated
as a mountain range. Nor can the other and lower ranges
lying east of the Sierra affect the case materially, for surely
more than ninety per cent of the rain and snow which fall
upon them are reevaporated in loco and the atmosphere ulti-
mately suffers no material loss of moisture.

When the winds blow constantly from a cool to a warmer
region they become warm and therefore dry ; and if they have
no opportunity to take up more moisture on the way the pas-
sage from a cool to a warm region is a sufficient cause of
aridity. This is, I conceive, the state of affairs which deter-
mines the climate of the western mountain region. The winds
blow constantly from the western quarters, being the " return-
trades." Local winds and perhaps large cyclones occasionally
turn the weathercock toward an easterly quarter, but the
general drift of the great atmospheric ocean is ever from west
to east* This prevailing air drift comes fiom the Pacific and
reaches the coast nearly or quite saturated with moisture. The
quantity of moisture required for saturation is dependent
chiefly upon temperature ; and the temperature of the air as it
reaches the coast is determined by oceanic conditions.

From the Aleutian Islands a coastwise ocean-current moves
southward, having a breadth of 500 miles or more, and extend-
ing as far southward as the latitude of Cape St. Lucas. Off
British Columbia and Alaska it may be regarded as a warm
current relatively to the adjoining land. Off the Californias
although its temperature rises notably with its southward
movement it may be regarded as a relatively cool current On
the more northerly shores its effect is to make the climate of
the adjacent coast warmer than it would otherwise be ; and its

* Tbis general statement requires some qualification when applied to southern
Arizona and southern New Mexico, though it is in the main applicable even there.

C. R Dutlon—Arid Climate of the Western U. S. 249

effect on the more southerly shores is to make them cooler.
Stated in another manner the relation is such that the tempera-
tures of the land areas in the high latitudes are lower than those
of the ocean, while in the low latitudes they are higher. In
the high latitudes, therefore, the winds blowing from the
Pacific are cooled by the land ; in the low latitudes they
are warmed by it. Hence the precipitation is copious in the
former regions and meager in the latter. Between the two
belts where these opposite effects are pronounced is a region
where they shade into each other, and though this intermediate
region cannot be marked out by distinct boundaries it may
still be said to exist in latitudes lying within the valley of the
Columbia Eiver.

The cause of an arid climate thus indicated may be regarded
as generally operative throughout the western mountain region ;
and it will no doubt appear upon full consideration to be much
more potent and widely extended in its action than any or
even all of the mountain ranges could be. It is, however,
greatly modified by the intervention of local causes, which
occasionally mask or obscure it. The precipitation in different
portions of the region is highly irregular and several modify-
ing causes can be indicated which, though they do not nullify
the more general one here set forth, frequently become much
more conspicuous in their effects. For instance, it is well-
known that the heaviest rainfall in the United States, except-
ing possibly upon some mountain tops, occurs upon the coast
of Oregon and Washington Territory. But as already indicated
this is the locality where we find the neutral axis, so to speak,
of the alleged causes favoring respectively humidity and
aridity, and where their effects are at a minimum or even at
zero. Moreover, the westerly winds saturated with moisture
here strike the coastwise mountains, and are suddenly thrown
upward several thousand feet before they have had time to
feel the heating effect of the land which is here very slight; and
the precipitation is thus very copious. Descending to lower
levels inland they soon become dry and produce a sub-arid
climate.

The most frequent variants of climate are the great differ-
ences of altitude in different portions of the west. The moun-
tain tops and summits of the plateaus are always well watered,
and in any given latitude the rainfall increases or diminishes at
a fairly definite rate with the altitude. But the variation of
rainfall with altitude is by no means a simple ratio. Between
4500 and 6000 feet the difference in rainfall is not great ;
between 6000 and 7500 feet it is very considerable ; between
7500 and 9000 it is still greater.

Moreover the rainfall is greater ceteris paribus in high latitudes

250 S. W. Ford — Additional Embryonic Forms of Trilobites.

than in low latitudes. In passing from the southern to the
northern boundary, if we compare localities of equal altitudes
along any given meridian, we shall find the rainfall steadily
though perhaps not uniformly increasing. This is an obvious
consequence of the theory suggested.

Although no very great effects upon the general condition
of aridity are here attributed to the depletion of moisture by
the passage of the winds over mountain ranges, it is still true,
no doubt, that highly important local effects are thereby pro-
duced. The rainfall at the eastern base of the Sierra Nevada,
and for two hundred miles east of it is most probably reduced
very greatly by this cause. In the sink of the Humboldt
Eiver, the annual precipitation seldom reaches four inches, and
may average not more than three inches. But as we pass
eastward beyond the wake of this range, its effects become
gradually less ; and long before the Wasatch is reached they
have become inconsiderable. Since the Sierra Nevada is the
longest, highest and widest of the individualized ranges of the
Eocky system, its local effect upon the humidity of the plains
and valleys lying immediately under its lee is greater than that
of any other. But the same kind of effect is preceptible in
some other ranges.

The discussion of the causes of local variations in climate
might be almost indefinitely extended. Nothing more is
designed here than to advert to one general cause of aridity
which prevails over the entire region, and which everywhere
persists, though it is often obscured, sometimes reversed and
sometimes reinforced by local causes.

Art. XXXVI. — On additional Embryonic Forms of Trilobites
from the Primordial Rocks of Troy, N. Y., with observations on
the genera Oltnellus, Paradoxides and Hydrocephalus ; by S.
W. Ford.

Among the various species of Trilobites of the genus
Paradoxides (abstracting those forms of which we know the
thoracic structure but imperfectly or not at all), there may be
distinguished two principal groups : One characterized by having
the second, and rarely also the first, pleuron prolonged consider-
ably beyond the succeeding ones; and the other by having all
of the anterior pleura, as we proceed backward, decreasing or
increasing in length, according to the species, in a regular man-
ner. As examples of the former we may instance Paradoxides
spinosus from the Bohemian Primordial, and P. Bennettii from
that of Newfoundland (and the majority of the Bohemian species

& W. Ford— Additional Embryonic Forms of TrifobiUs. 251

might be included) ; and of the latter the most if not all of the
British species, all of the Swedish, and the American P. Harlani.
Why two species, so closely allied as are the P. spinosus and
P, Harlani, should yet differ in the particulars mentioned, has
all along been looked upon as a mystery ; but there can be but
little doubt that all who have seriously contemplated the mat-
ter, have regarded these differences as possessing a deep and
peculiar significance.

The five known species of the American genus Olenellus ad-
mit of a similar grouping, and, if we confine ourselves to the
adult forms alone, upon the ground of thoracic differences
equally pronounced with those obtaining in the genus Para-
doxides. Three of them, 0. Thompsoni, 0. Vermontan.ua and 0.
Gilberti have the third pleuron conspicuously prolonged beyond
the others ; while in 0. asaphoides it forms, with those preceding
and succeeding it, a regularly graduated series. The thorax of
the fifth species, 0. Howelli, has not been observed. These dif-
ferences long since attracted the attention of paleontologists, and
led at least one authority to exclude the 0. asaphoides from the
genus altogether, — apparently overlooking the fact that a simi-
lar course of reasoning would compel us to break up the genus
Paradoxides* But the facts now in hand show that Olenellus
asaphoides is, beyond a doubt, a genuine Olenellus. As I shall
have frequent occasion, in the course of this article, to refer to
both the long and short ribbed forms spoken of, I shall desig-
nate them, whether referring to Paradoxides or Olenellus, as
the macropleural and brachypkural types respectively. These

Fig. 1. — Embryonic form of Olenellus asaphotdes, enlarged fi
2.— Another specimen, representing a more advanced stage of d
larged four diameters. 1'ig. 3. — A still older specimen, the characters of which
are nil only those of the adult, enlarged two diameters.

terms, however, as will be seen further on, are not intended to
be expressive of sharply defined or clearly distinct groups or
sub-groups, but are here introduced merely for the sake ol con-
venience.

* Thirteenth Regents' Report on the N. Y. State Cabinet, p. 1 19.

252 & W. Ford— Additional Embryonic Forms of TrOobihss.

As the result of some recent researches in the Primordial
beds of Troy, N. Y., I have obtained two specimens which
afford a very satisfactory solution of the structural peculiarity
noted above in the case of Olenellus asapkoides ; besides offering
a probable explanation of the brachypleuristn observed in Para
doxides. They tend, moreover, to prove that the macroplearal
species of thai genns should be regarded as typical. Both are
young specimens of Olenellus asaphoides and unusually perfect.
Their leading characters may be stated as follows:

Fig. 1 represents the younger and by far more important
specimen, the place of which, in the embryonic series, is
probably about mid-way between the forms represented by
figures 2 and 3 of my former article (this Journal for April,
1877). There are either nine or ten body-segmenls, the last
three or four being somewhat indistinct The third pleuron is
considerably larger arid longer than the others, the points
extending backward well beyond the limits of the thorax. All
of the pleura have the characteristic groove of Olenellus'. The
posterior margin of the head is sharply geniculated at the sutures,
throwing the genal spines notably forward upon the cephalic
periphery, precisely as in Paradoxides spinosus Boeck and P.
pusiilus Barrande (see figs. 5 and 6). The interocular spines
are prominent, and, although slightly damaged, can be seen to
have reached nearly to the third body-segment Moreover, these
spines and the genal spines are still parallel with each other as
in earlier embryonic life. The glabella is marked by three
furrows besides the neck-furrow, all of which run entirely
across it as in the known preceding stages of development
Bohemian Pa b a doxides.

Fig. 4.— Young specimen of Paradoxides spinosus Boeck ap., twice enlarged.

Fig. 6. — Very perfect apecimen of P. piisilitts Bnrnuide, enlarged 10 diameters.

Fig. 6. — Complete individual of P. in/lotus Corda, enlarged i diameters. All
after Barrande.

The length or the specimen, from the middle of the front
margin to the extremity of the third pleuron, is 0"26 of an inch,

S. W. Ford — Additional Embryonic Forms of Trihbites. 253

and the width of the head, exclusive of the posterior spines 0*14.
The entire surface is plain, or without any trace whatever of
ornamentation.

Fig. 2 represents the second and older specimen, the left-
hand portion of which is partly restored in the drawing. The
place of this specimen in the developmental series removes it
a number of steps from the form just described, allying it
much more nearly to those forms in which the metamorphoses
are at an end. There are fourteen body-rings, and behind
these a minute, rudely semi-circular plate (the pygidium),
which I believe to have been the source of all the body-
segments. The third pleuron is still conspicuously longer than
the others ; but its relative width, as compared with that in fig.
1, is much reduced, and its direction changed. How far
backward it extended it is impossible to say, as both the right
and left hand points are wanting; but the pleural furrows are
here relatively much shorter than in fig. 1, and this fact
strorfgly argues a corresponding abbreviation of the pleural
points. The head forms rather less than a semi-circle, and has
the posterior margin curved slightly forward ; in other speci-
mens, however, of the same size, and even smaller, the pos-
terior margin is completely transverse, and hence the curving
in the present instance is evidently an individual peculiarity.
The interocular spines are very small, but are still attached to
the fixed cheeks. The genal spines are slender, reach as far
backward as the third pleura, and here form with the inter-
ocular spines a very appreciable angle. The glabella is some-
what crushed, but is seen to be furrowed nearly as in the adult.
I cannot say with certainty whether all of the furrows in
advance of the neck- furrow were separated on the median line
or not. The surface is nearly smooth, but just beyond the
eyes some obscure striation can be detected. The length of
this specimen is 0*33 of an inch, and the breadth at the genal
angles 0 24.

In fig. 3, which is an outline representation of fig. 5 of my
former article, the third pleuron forms, with the others, a regular
series, the interocular spines have disappeared, the head has
assumed the form which it afterward retains, and the develop-
ment is completed. Between this form and the preceding one,
I have a considerable number of others, which leave no doubt
as to their being fundamentally one and the same.

We learn, from the foregoing, the important fact, that the
macropleural and brachy pleural types under the genus Olenellus
can in no wise be regarded as indicative of fixed or indepen-
dent groups, 0. asapkoides being macropleural in embryonic
life and brachypleurai in the adult; and this breaks down the
dividing line between them. Now, according to a well-known

254 <S W. Ford — Additional Embryonic Forms of Trilobites.

canon in Natural History, 0. asaphoides must be regarded as
higher in grade than its macropleural congeners; and this
being true, we are naturally led to inquire whether the brachy-
pleural forms under the genus Paradoxides are not also higher
in grade than their macropleural congeners. Unfortunately,
the direct evidence required to decide this question is wanting;
but there are certain known facts having an important bearing
upon it, and to these I shall now refer.

Fig. 1. — Ilead and first 8 body- segments of adult specimens of Paradotx&du
spinomit (macropleural], reduced two-thirds. Compare with fig. 4. Fig. 8. — Head
and 9 forward pleura of adult of P. Tessini Brongn. (brachypleural), reduced
one-half (after Angeliu).

Among the macropleural Paradoxides described by Barraude,
there are a number of species of which we lack either one or
other of the growth extremes ; some of them being known only
by adult examples, and others only by forms which appear to
.be the young. I say appear to be, because, while I have myself
no doubt that P. pitsillus is a young Trilobite, there is nothing
in the aspect of P. inflatus except its small size and excessively
produced second pleura to indicate that it was not full grown.
In the case of P. spinosus and P. Ilohemicus, however, we know
both the young and mature forms; and, as will be seen by
figure 4, P. spinosus, in the young state, was. not only pro-
nouncedly, but even extravagantly, macropleural, the points of
the second body-segment extending, like those of the third in
the young of 0. asaphoides, backward beyond the thorax ; and
in the young of P. Bohemians this peculiarity is equally strik-
ing. But although this feature, in both of these species, was
well-nigh obliterated in the adult, yet in neither was the pro-
cess carried sufficiently far to render them brachypleural
specieB. Nevertheless, it is not difficult to see that such a
result might easily have been attained; and from what we now
know of the history of 0. asaphoides, coupled with the facts
just stated, there ia strong presumptive evidence that the
brachypleural species of Paradoxides were macropleural in early

jS W. Ford — Additional Embryonic Forms of Trilobites. 255

life. It is earnestly to be hoped that the British and Swedish
savans will institute, at no distant day, new researches, with the
view of reaching a clear and final settlement of this important
question.

But by far the most interesting feature of the young speci-
men of Oknellus asaphoides first described yet remains to be
particularly considered. I allude to the remarkable Paradox-
ides-like run of the outer portion of the posterior margin of the
head, shown at a a in figure 1. This feature, though varying
in the intensity of its expression in the several species, is, if we
exclude one or two species which are in other respects abnor-
mal, constant in the genus Paradoxides, and appears to have
been especially emphasized in the forms of the macropleural
section; but it is shown in none of the other species of the
genus Olenelius, and even disappears altogether, as we have
seen, in 0. asaphoides, during embryonic life. After much
study of the subject, I am convinced that we have here the
exhibition of a character, afterwards lost, which in Paradoxides
may be regarded as fixed. It is true, that in 0. Gilberli* the
posterior margin is deeply emarginate in the vicinity of the
postero-lateral angles; and this feature, as shown by the figures
given in the Vermont Geological Eeports, is sometimes present
in 0. Vermontanus ; but the facial suture, in the former species,
does not cut the posterior margin at the point of geniculation
as in Paradoxides, but far within it ; and this appears to hold
good for the youngest specimen which Dr. White figures. It is
evident, to my mind, that this character is not the same with
that under discussion occurring in the young of 0. asaphoides ;
and I believe that no one, who will take the trouble to examine
the facts, will be likely to reach a different conclusion. The
discovery, however, of still younger specimens of 0. Gilberii is
greatly to be desired, as they would doubtless serve to throw
much light upon the whole question.

Now, if the foregoing interpretations be correct, Oknellus
asaphoides must be regarded as higher in grade than any of the
normal species of Paradoxides ; and such I believe its history
and structure alike declare it to be. The following additional
facts and considerations appear to me to sustain this conclusion,
and tend to clear up a number of points hitherto obscure con-
nected with the subject.

Fig. 10 represents the plan of structure of the head of a
Swedish Paradoxides, described by J. G. 0. Linnarsson, in
1871, under the name of P. Kjerulfi.\ The thorax in none of
the examples figured is well preserved, but from the study of

* White, Rep. upon Geogr. and Geol. Explor. and Surv. west of the One Hun-
dredth Meridian. Part I, vol. iv, Paleontology, p. 44, pi. 2 figs. 3 a-c.
■J Oefversigt af Vetenskaps-Akademiens Forhandlingar, 1871, No. 6, Stockholm.

256 & W. Ford—Additional Embryonic Form* of TrUobita. .

tbe bead alone, no one thoroughly acquainted with Primordial
Trilobites would hesitate to pronounce it a Paradoxides; and
M. Ltnnarsson thus uoquestioningly describes it. It is only
when we come to compare it with such forms as OUndha

Kg. 9 — Head (minus the free cheeks) and thorax of Hydrocephaba Sattmoid&
Barrande, enlarged 16 diameters. Fig. 10. — Plan of structure of the head of
Paradoxides Sjervlfi I.innarBKon. from the Swedish Primordial, DM. size. Kg.
1 1. — Head of Hydrocephalus cartas Barrande (the free cheeks restored in out-
line), enlarged 6 diameters.

asaphoides and 0. Gilberli, and especially with the yonng of
the former, that the real difficulty arises. It differs from the
other forms of the genus mainly in: (1) The possession of a
pair of spinous processes extending from the neck-furrow back-
ward across '.he posterior margin (fig. 10, aa); (2) Tbe appar-
ently firmly soldered facial sutures; and (3) The marked
tumidity of the central portions of the fixed cheeks (fig. 10, cc).
All of these characters, if we regard the spinous processes as
the structural homologues of the interocular spines of Oleneltus
asaphoiiles^- see figs. 1 and 2, bb — (and whether so or otherwise,
I believe them to have been clearly functionally such) occur
likewise in 0. asaphoides; the first and third having here, how-
ever, only a transitory existence, while the second characterizes
all the stages. 0. asaphoides further shows its close relation-
ship with the Swedish form in having all of its glabellar far-
rows, in early embryonic life, extending entirely across, instead
of being interrupted, as in the more advanced and mature
forms, on the median line. There can be scarcely a doubt that
the figure of Paradoxides Kjerulfi above giveti represents a fully
developed form, and that all of the characters which it exhibits
were permanent in it*

The above facts, taken in connection with those stated
earlier, strongly argue that Olencllus asaphoides may be safely
regarded as higher in grade than any known form of Paradox-

* It is worthy of remark, in this connection, that the solidity of the head-shield,
due to the firm coalescence of the free and fixed cheeks in front of tbe eye,
appears tu have characterized all the known species of OleneBus; and that in one
of them at least, O. Thompsoni [Bg. 12), the central portions ol the fixed cheeks,
or interocular spaces, were notably inflated in adult life.

& W. Ford — Additional Embryonic Forms of Trilobites. 257

ides whatsoever ; P. Kjerulfi being a normal species jn so far as
concerns the contour of the posterior margin of the head, but
in other particulars one of the most widely divergent; and we
here touch, it seems to me, the real core of the matter. The
all-important question is, what is the precise nature of the rela-
tionship subsisting between these two species? We might,
indeed, rest content with the deductions already arrived at and
the inferences to which they lead; among which latter may be
mentioned this: that if 0. asaphoides has the superior zoological
rank above accredited to it, it is probably a more recent form ;
and this fact accords well with the collective testimony of the
other forms composing the local fauna (that of Troy, N. Y.,)
to which it belongs ; but are not the special relationships
pointed out, one and all, the mere incidents of some profounder,
all-embracing relationship? That such they are I cannot well
doubt; and I am further compelled to add, that the study of
the facts herein presented has produced in my mind a strong
conviction that this relationship is probably deeper than an
ordinal, a family, or even a generic one — in short, that it is
genetic. And that this view of the case will ultimately pre-
vail, there is, in my opinion, every reason to believe.

The weight of the evidence in this case may perhaps be
better appreciated by a succinct restatement of it, and it
amounts to this: that four out of five'of the fixed characters
of P. Kjerulfi above enumerated appear in the extreme
young of 0. asaphoides only to disappear; and in addition
to this it loses during early life, as we have seen, its
macropleurism. Had we but a single embryonic character
linking this species with Paradoxides the case would be
different, but we here have a whole congeries of such char-
acters, clearly and unmistakably shown. It is true that, in bis
later writings (1879), M. Linnarsson refers to P. Kjerulfi as
Paradoxides (Olenellus) Kjerulfi; but in 1877, shortly after the
publication of my former article, we find him changing the
title of 0. asaphoides, as given by me, to Paradoxides ("Olen-
ellus") asaphoides ; that is to say, he endeavored to get over the
difficulty by first turning 0. asaphoides into a Paradoxides, and
then turning P. Kjerulfi into an Olenellus, neither of which
attempts have proved, however, at all satisfactory. I believe
that, even if 0. asaphoides be genetically related to P. Kjerulfi,
we may yet with propriety consider it as generically distinct,
and as such I still continue to look upon it. Nevertheless, I
am free to own that, if we take into account the entire knowu
range of structural characters under the genus Paradoxides, I
see nothing, at present, in the finished form of 0. asaphoides,
that can be regarded as absolutely distinctive, except the seg-
ment furrow. If it be true that 0. asaphoides has resulted from

258 S. W. Ford— Additional Embryonic Form* of TrilobUes.

the evolution of some Paradoxides-hke form, then tbe lineni
descent probably extends backward through the macropleural
section of the genus Oknellus to some such species as Para-
doxides Kjeruiji, or perhaps to some still more divergent form
of Paradoxides, with which we are as yet unacquainted.

Pig. 12. — Adult specimen of Olendlus Tkompsoni Hall, reduced ODe-half. Fig.
13.— Medium sized individi^ of 0. Vermontarms Hall, natural hum. Both after
(lall.

Hydrocephalus is a still somewhat obscure genus occurring in
the Bohemian Primordial; but, as long since pointed out by
Barrande, one of the close allies of Paradoxides. It differs
from Paradoxides mainly in the course of its facial sutures, and
in the peculiar position of its genal spines; the former striking
the posterior margin, according to Barrande, in such a way as
to leave the latter attached to the fixed cheeks (see fig. 11, ad).
Barrande considers the head to have had the form shown in
the figure referred to, but the free cheeks have never been
observed. Hence a doubt may well exist as to whether what
he here calls the genal spines are truly such. M. Linnarsson
considers them the probable homologues of the spines of the
fixed cheeks of his Paradoxides {"Otendlus'') KjervXfi, and the
interocular spines of Olentltus asaphoides. It is possible that
his view is the correct one, and, if so, the head, when perfect,
probably had much the form of that in fig. 6. At present,
however, I do not share this opinion, believing them to be
altogether peculiar. The discovery of a perfect specimen is
greatly to be desired. Anopolenus (Salter) is another of the
close allies of Paradoxides; and in the P. expecfans of Barrande
(Syst Silur., etc., vol. i, supplt, pi. 3, figs. 33-35, and pi. 14,
fig. 30) we have a type so closely resembling it as to strongly

S. W. Ford — Additional Embryonic Forms of Trilobites. 259

suggest for them a genetic kinship (see Hicks, Quart. Jour.
Geol. Soc., vol. xxviii, pi. 7, figs. 1-11). Salter states that, in
the British Primordial, the genera Paradoxides, Anopolenus and
Olenus follow each other in regular order — first Paradoxides,
then Anopolenus and lastly Olenus ; and in America we appear
to have a like succession — first Paradoxides, then Olenellus, and
lastly the Olenoid types of the western States.

The remarkable intersection of differential characters observed
in the embryonic forms of Olenellus asaphoides, and the trans-
formations there noted, appear to me to point to the Embryo as
the principal theatre of organic evolution in general ; and they
strongly suggest, to my mind, the operation of profounder laws
than any, hitherto assumed, as having effectively directed its
course. It seems well-nigh absurd to ascribe such effects to
natural selection, or the influence of environmental conditions,
although such influences have, no doubt, to some extent, modi-
fied the total result. So far, however, as we are enabled to
judge, the conditions of existence in Primordial times were
remarkably uniform, and the a struggle for existence " was
probably less a struggle then than now. And if it be true that
the transformations wrought were mainly completed in embry-
onic life, and that, too, largely independent of external influ-
ences, it is no wonder that the great wealth of Silurian life still
lies before us practically a sealed book, for it is only in excep-
tional instances that we may hope to be permitted to study the
embryology of animal forms long extinct.

In the preparation of this paper I have all along felt my own
unworthiness to deal in a befitting manner with the difficult
problems which its subject matter presents; while as concerns
the principal conclusion reached, or that touching the question
of genesis, I should prefer to be understood as expressing in it
rather my present convictions than my mature or final judg-
ments. Nevertheless, I believe it to have a veritable basis in
the known facts, and that its presentation is fully warranted by
them; but those better qualified to judge may decide differ-
ently,' and thus the real truth of the matter, even if I have
missed it, will be likely, sooner or later, to come out. I have
thought it well to assume but little, and to proceed according
to the light of the evidence.

June 13th, 1881.

260 K S. Holden— Observations of Oomet b, 1881.

Art. XXXVIL— Observations of Gomel b, 1881, made at Ae
Washburn Observatory, University of Wisconsin, Madison; by

Edward S. Holden.*

The following observations of the bright comet of 1881 have
been made at the Washburn Observatory, with the Clark
equatorial of 155 inches aperture, mostly with an eye-piece
magnifying 145 diameters, having a field of 25''5.

The accompanying engravings first appeared in Science of
July 23 and August 6, and have been kindly furnished by the
editor. In these (except in the case of the drawing of July 11),
the darker the shading the brighter the corresponding part of
the comet

The Washburn Observatory is 0h 49m 25"'8 west of Washing-
ton. The times are, however, Chicago mean times, or corre-
spond to a meridian 0h 7m 11"-1 east of our own, that is 0* 42m
14"'7 west of Washington.

*r/

Figure 1 ; Juno 24, 14" in. t. — This figure is intended to show
the whole structure of the head of the comet, with its envelopes.
There is a star within the tail.

Figure 2; June 25, 10a m. t. — Sky hazy and outlines of the
comet not well seen. The drawing shows only the structure of

* For the cuts illustrating Professor Holder's paper, this Journal is indebted to
Mr. John Miuncls, editor of ''Science," in whose pages the above illustrations
wure Qrst published.

R & Bolden— Observations of Gomel b, 1881.

"Q^

f."

2**2 jE & Hotden— Observations of Comet ft, 1881.

the head. The nucleus is not round and is eccentric in the envel-
opes. The arrow shows the parallel.

Figure 3; Jnne 28, II" 22'" m. U — Hazy and cloudy.

Figure 4 ; June 27, 13" m. t.

Figure 5 ; June 28, 10" m. t.
Figure 6; June 29, 9b 30m m.
til! July 8.

—I was absent from Madison

Figure 7; July 8, 101' 35m m. t.— Moonlight. The nucleus is
not (loulile. There is a dark narrow channel between the follow-
n the figure.

ing side of the nucleus and the envelopes, :

Figure 8; July ll,9b 30m, m. t. — Strong moonlight and twi-
light. This cut gives bright portions of the comet by white

E. S. Eolden— Observations of Gomel b, 1881. 263

Figure 9; July 13, 9" SOm ro. t.

Figure 10; July 14, 10b 20m m. t. — Moonlight.

Figure 11 ; July 17, 10b 45"" m. t.

Figure 12; July 18, 9h 30m-llh 0m m. t.— The nucleus is double
(it has not been previously), p=2T5", s=i"-5, with a dark space
between the parts.

July 19; 9" 45ra ra. t. — Appearances same as last night, but
fainter. The nucleus is elongated in ^>=280°±. The second
nucleus is in p=270° *=l" to 2".

July 24; 9h 35m m. t. — The nucleus is double, p = 225° (4)
8=2"-«2 (3). The diameter of the principal nucleus in ^=135°, is
l"-68 (2).

The micrometer measures by Mr. Burnham.

July 26 ; 9h 3nl m. t The nucleus is round.

July 27; 10h 10m m. t — The nucleus seems elongated in
/)=250°, but I am not sure.

After this date the comet was examined on several occasions
without finding any peculiarity worthy of mention. It is to be
noted that there is no doubt whatever as to the fact that the
nucleus was double on July 18, July 19 and July 24. I am
almost equally positive that it was not double on the other
dates specified.

It appears to me that these observations are of interest in con-
nection with those of Prof. 0. Stone at the Cincinnati Observa-
tory, and of Mr. Wendell at the Harvard College Observatory.

Washburn Observatory, Madison, WiBconain, August 25, 1881,
Am. Jour. Sol— Third Sbrieb, Vol. XXII, No. 130.— October, 1881.
18

264 W. J. McOee—Tftickness of Ice-sheet at any Latitude.

Art. XXXVIII. — On the thickness of the Ice-sheet at any

Latitude ; by W. J. McGek*

1. Estimates of thickness.

First preliminary estimate. — It was shown in Part I of this
paper that the accumulation of glacier ice is dependent on pre-
cipitation ; and in a general way it may be considered propor-
tional therewith. It may also be assumed that the precipita-
tion, and hence of course the accumulation of ice, is propor-
tional to the vapor-tension. If then the thickness at any lati-
tude is known, that at all other latitudes can be readily com-
puted.

Professor Dana has shown f that the thickness of the Quater-
ternary ice-sheet over the Canadian highlands (about N. lat
48° to 50°) must have been at least 12,000 feet As this accu-
mulation took place under conditions less favorable than those
considered in the present discussion, it may be assumed that
a thickness of three miles might obtain at lat 40°. The thick-
ness at each latitude from 40° to the pole would accordingly be
as represented in table XVIL The data forming the basis of
the computation are derived from sources previously enumer-
ated

Table XVIL

Greatest thickness

of Ice-field from lat. 40°

to the Pole.

Latitude.

Temperature.

Vapor-tension.

Thickness of Ice,

40°

+ 565°

0-457 in.

3-000 miles.

417

•264

1-733

302

168

1103

160

•090

•591

6*8

059

•387

•048

•315

' Second preliminary estimate. — It would doubtless be more sat-
isfactory to base estimates upon the present accumulation of ice
over polar regions, if the quantity were at all definitely known.
The uncertainty regarding the exact amount is so great, however,
especially in arctic regions, that any such estimate will serve
only as a check on that already made.

It may be almost arbitrarily assumed that, if the land ice exist-
ing on the zone bounded by the eightieth parallel were uniformly
distributed, it would form a sheet fifty feet in thickness. Now
too little aqueous vapor is conveyed into arctic regions to per-
mit the accumulation of sufficient ice to form an effective con-
denser. It is probable that, in consequence of this imperfection

* This article is from Mr. McGee's paper on "Maximum Synchronous Glacia-
tion," making 65 pages of the Proceedings of the American Association for
the Advancement of Science, vol.xxix, 1880.

f This Journal, March, 1873.

W. J. McOee — Thickness of Ice-sheet at any Latitude. 265

of the arctic condensing apparatus, enough moisture is not con-
gealed, but allowed to fall as rain and thus to melt a portion of
the ice, to reduce the accumulation which should take place by
fully two-thirds. Were it not for this the accumulation might
reach 150 feet on an average, and 300 feet near the marein.
The corresponding maximum thickness when the ice extenaed
ten degrees farther from the pole would be about 400 feet.
These estimates enable us to institute a comparison with the
antarctic ice-sheet.

Only about one-seventh of the seventieth parallel of north
latitude is so free from land as to present no obstruction to the
carrying in of vapor from more southerly regions. In the south-
ern hemisphere, on the other hand, the whole parallel is prac-
tically open to the introduction of vapor from the adjacent tem-
perate zone. The accumulation here ought accordingly to
be seven times as great as in arctic regions, or 2,800 feet near
the margin. It will probably not be objected that these esti-
mates are too low, as they have purposely been made as large
as seems at all consistent with the present condition of polar
regions. It has already been shown that the present accu-
mulation in these regions is probably about as great as ever can
have existed.

Accepting the largest of these estimates as representing the
greatest possible thickness of the icecap at lat. 70°, and com-
puting the thickness at other latitudes as in table XVII, the
respective values are found to be as follows : —

Lat. 40° 1421*7 feet, = 2693 miles.

11 50 8213 " = 1-555 "

" 60 5226 " != -990 "

" 70 2800 " = -580 "

u 80 1835 " = '348 "

" 90 1493 " = '283 "

The approximate correspondence between the two estimates- is
apparent.

Final estimate. — It may be assumed that, in a hemisphere
with parallel isotherms and isobars, all vapor is precipitated
nearer the poles than where it is formed. Two factors (perhaps
unequal), tending to produce opposite results in the final com-
putation, will be disregarded. These factors are (1) the eleva-
tion of temperature outside the icefield illustrated by table VI,
and (2) the less frequent saturation of the atmosphere in frigid
climates. As shown by the tables of Section II, when the ice-
sheet reached any latitude the vapor which had previously been
borne polar-ward would be precipitated near the margin of the
sheet, mainly in the form of snow. The precipitation would
hence be greater than the normal, at the border of the ice, in

the ratio of p :p-\ , where p denotes normal precipitation, o

266 W. J. McOee — Thickness of Ice-sheet at any Latitude.

area of zone bounded by margin of ice, and n area of hemis-
phere. Table XVIII has been computed in accordance with
this ratio.

Table XVIII.

Maximum thickness

of Ice-cap.

Latitude.

Temper-
ature.
— Dove.

Vapor-
tension.

Thickness of Ice-cap.
Value of

p o Feet. Miles.

" n

10°

+ 79-9° P.

1-020 in.

1-863 55,871

10*582

774

•940

1-559 46,753

8*855

69-8

•728

1092 32,749

6-203

565

•457

•620 18,594

3422

41-7

•264

•326 9,777

1-852

302

168

•191 5,728

1-085

16-0

•090

•095 2,800

•530

•059

•060 1,799

•341

2*3

•048

•048 1,440

•273

It is almost needless to reiterate the proposition already de-
monstrated, that vapor could not be borne far enough within
the margin of the ice to affect materially the above results, with-
out seriously deranging the sequence of phenomena to which
the ice owes its origin and conservation.

The suggestion that the property of flowing might enable
the ice to assume a uniform depth may be anticipated by men-
tioning that the polar slope above given is less than one-tenth
of that requisite, according to Hopkins's experiments, to pro-
duce the slightest motion.

2. Comparison with the ice-cap theory.

Concomitants of the theory. — The ice-cap theory seems to have
been framed chiefly to account for the equatorial motion of the
Quaternary glaciers. Now, to be consistent with itself, the
theory requires that the assumed thickness of the cap shall be
sufficient to form a slope down which ice will flow by gravitation
alone. Hopkins found that ice barely moves on a slope of one
degree ; ana there is no evidence that existing glaciers move on
a less slope. To form such a slope from lat. 40° to the pole,
the polar thickness of the ice would have to be 60 miles — the
"twenty leagues" of Adhemar. If, with the same mean thick-
ness, it extended only to lat. 45°, the content of the cap would
be 575,000,000 cubic miles, equal (the density of ice to water
being as -92 to 1) to 529,000,000 cubic miles of water. But
taking the water-area of the globe at 145,000,000 square miles,
and the mean depth at 12,144 feet, or 2*3 miles,* we find that

* Sir Wyville Thompson says: "It seems now to be thoroughly established by
lines of trustworthy soundings which have been run in all directions, that the
average depth of the ocean is a little over 2,000 fathoms." This Journal, vol.
xvi, (1878), p. 351. Dr. Kriimmel estimates the mean depth at 1817 fathoms.
See note in Popular Science Monthly, vol. xvi, Dec. 1879, p. 287.

W. J. McOee — Thickriess of Ice-sheet at any Latitude. 267

all the water of the globe amounts to only 335,500,000 cubic
miles or but little more than three-fifths of that required to form
the assumed ice-cap.

If the above estimate seems too large, let it be reduced by
seven-eighths, which will bring it well within the bounds pre-
scribed by more moderate advocates of the theory ; but even
then it is too large to be admissible; for it would require one-
fifth of the water of the globe to form even the smaller ice-cap.
But diminishing the water of the globe one-fifth would diminish
the water-covered area by a considerably larger fraction ; for
the sea bottom does not descend uniformly to the deeper abysses.
The slope is, usually, gentle for a considerable distance from
the shore, and then steep and precipitous to the abyssal depths.
Reducing the water one-fifth would therefore reduce the area
covered by it one- third. Suppose now the ice-cap be around
the south pole : The diminution caused by the removal of so
much water, and the further diminution resulting from the dis-
placement of the earth's center of gravity, would drain nearly
all the water from the northern hemisphere. But the conse-
quent stoppage of marine circulation and of the formation of
aqueous vapor would, as shown in Section I, so increase the
diurnal and annual thermometrical range as to render the hem-
isphere uninhabitable for existing organisms.

Relative mass of the two ice-caps. — Assuming the ice-field tab-
ulated above to be of uniform thickness for five degrees on each
side of the parallels given, and to extend to lat. 45°, its mean
depth would be 1*356 miles. Its mass would therefore be only
Tlj of the larger or little over £ of the smaller of the ice-caps
considered in the preceding paragraphs. It should be borne
in mind, too, that this is the maximum synchronous accumula-
tion under more favorable conditions than would be likely to
obtain in nature. The consequent displacement of the earth's
center of gravity has accordingly not been computed.

Conclusion. — It seems quite safe to affirm that in any exten-
sive polar ice-field the thickness will decrease from near the
margin toward the pole, where the attenuation will be greatest.
It may accordingly be concluded that a sufficient accumulation
of polar ice to displace seriously the earth's center of gravity
or influence the motion of middle-latitude glaciers, can never
have taken place in this hemisphere.

268 Sir John Lubbock1 s Address.

Art. XXXIX. — Address of Sir John Lubbock, President of the

British Association at York,

* * The connection of the British Association with the
City of York does not depend merely on the fact that our first
meeting was held here. It originated in a letter addressed by
Sir David Brewster to Professor Phillips, as Secretary to your
York Philosophical Society, by whom the idea was warmly taken
up. The first meeting was held on September 26, 1831, the
chair being taken by Lord Milton, who delivered an address,
after which Mr. William Vernon Harcourt, Chairman of the
Committee of Management, submitted to the meeting a code of
rules which had been so maturely considered, and so wisely
framed, that they have remained substantially the same down
to the present day.

Of tnose who organized and took part in that first meeting,
few, alas, remain. Brewster and Phillips, Harcourt and Lord
Milton, Lyell and Murchison, all have passed away, but their
memories live among us. Some few, indeed, of those present
at our first meeting we rejoice to see here to-day, including
one of the five members constituting the original organizing
Committee, our venerable Vice-President, Archdeacon Creyke.

The constitution and objects of the Association were so ably
described by Mr. Spottiswoode, at Dublin, and are so well
known to you, that I will not dwell on them this evening.
The excellent President of the Royal Society, in the same
address, suggested that the past history of the Association
would form an appropriate theme for the present meeting.
The history of the Association, however, is really the history
of science, and I long shrunk from the attempt to give even a
panoramic survey of a subject so vast and so difficult ; nor
should I have ventured to make any such attempt, but that I
knew I could rely on the assistance of friends in every depart-
ment of science.

Certainly, however, this is an opportunity on which it may
be well for us to consider what have been the principal scien-
tific results of the last half-century, dwelling especially on
those with which this Association is more directly concerned,
either as being the work of our own members, or as having
been made known at our meetings. I have, moreover, espe-
cially taken those discoveries which the Royal Society has
deemed worthy of a medal. It is of course impossible within
the limits of a single address to do more than allude to a few
of these, and that very briefly. In dealing with so large a
subject I first hoped that I might take our annual volumes as
a text-book. This, however, I at once found to be quite im-
possible. For instance, the first volume commences with a

Sir John Lubbock's Address. 269

Report on Astronomy by Sir G. Airy ; I may be pardoned, I
trust, for expressing my pleasure at finding that the second was
one by my father, on the Tides, prepared, like the preceding, at
the request of the Council ; then comes one on Meteorology by
Forbes, Radiant Heat by Baden Powell, Optics by Brewster,
Mineralogy by Wheweli, and so on. My best course will
therefore be to take our different Sections one by one, and
endeavor to bring before you a few of the principal results
which have been obtained in each department.

The Biological Section is that with which I have been most
intimately associated, and with which it is, perhaps, natural
that I should begin.

Fifty years ago it was the general opinion that animals and
plants came into existence just as we now see them. We took
pleasure in their beauty ; their adaptation to their habits and
mode of life in many cases could not be overlooked or misun-
derstood. Nevertheless, the book of Nature was like some
richly illuminated missal, written in an unknown tongue ; the
graceful forms of the letters, the beauty of the coloring, ex-
cited our wonder and admiration ; but of the true meaning
little was known to us; indeed we scarcely realized that there
was any meaning to decipher. Now glimpses of the truth are
gradually revealing themselves; we perceive that there is a
reason — and in many cases we know what that reason is — for
every difference in form, in size and in color ; for every bone
and every feather, almost for every hair. Moreover, each prob-
lem which is solved opens out vistas, as it were, of others per-
haps even more interesting. With this great change the name
of our illustrious countryman, Darwin, is intimately associated,
and the year 1859 will always be memorable in science as hav-
ing produced his great work on "The Origin of Species." In
the previous year he and Wallace had published snort papers,
in which they clearly state the theory of natural selection, at
which they had simultaneously and independently arrived.
We cannot wonder that Darwin's views should have at first
excited great opposition. Nevertheless from the first they met
with powerful support, especially, in this country, from Hooker,
Huxley and Herbert Spencer. The theory is based on four
axioms : —

44 1. That no two animals or plants in nature are identical in
all respects.

" 2. That the offspring tend to inherit the peculiarities of
their parents.

u 3. That of those which come into existence, only a small
number reach maturity.

" 4. That those, which are, on the whole, best adapted to
the circumstances in which they are placed, are most likely to
leave descendants."

270 Sir John Lubbock's Address.

Darwin commenced his work by discussing the causes and
extent of variability in animals, and the origin of domestic
varieties ; he showed the impossibility of distinguishing be-
tween varieties and species, and pointed out the wide differences
which man has produced in some cases — as, for instance, in oar
domestic pigeons, all unquestionably descended from a com-
mon stock. He dwelt on the struggle for existence (which has
since become a household word), and which, inevitably result-
ing in the survival of the fittest, tends gradually to adapt any
race of animals to the conditions in which it occurs.

While thus, however, showing the great importance of natu-
ral selection, he attributed to it no exclusive influence, but
fully admitted that other causes — the use and disuse of organs,
sexual selection, etc. — had to be taken into consideration.
Passing on to the difficulties of his theory he accounted for the
absence of intermediate varieties between species, to a great
extent, by the imperfection of the geological record. Here,
however, I must observe that, as I have elsewhere remarked,
those who rely on the absence of links between different species
really argue in a vicious circle, because wherever such links do
exist they regard the whole chain as a single speciea The
dog and jackal, for instance, are now regarded as two species,
but if a series of links were discovered between them they
would be united into one. Hence in this sense there never
can be links between any two species, because as soon as the
links are discovered the species are united. Every variable
species consists, in fact, of a number of closely connected links.

But if the geological record be imperfect, it is still very in-
structive. The further paleontology has progressed the more
it has tended to fill up the gaps between existing groups and
species, while the careful study of living forms has brought
into prominence the variations dependent on food, climate,
habitat, and other conditions, and shown that many species
long supposed to be absolutely distinct are so closely linked
together by intermediate forms that it is difficult to draw a
satisfactory line between them. Thus the European and
American bisons are connected by the Bison priscus of Prehis-
toric Europe ; the grizzly bear and the brown bear, as Busk
has shown, are apparently the modern representatives of the
cave bear ; Flower has pointed out the paleontological evidence
of gradual modification of animal forms in the Artiodactyles;
while among the Invertebrata, Carpenter and Williamson have
proved that it is almost impossible to divide the Foraminifera
into well- marked species; and, lastly, among plants, there are
large genera, as, for instance, Rubus and Hieracium, with refer—
ence to the species of which no two botanists are agreed.

The principles of classification point also in the same dir<

Sir John Lubbock's Address. 271

tion, and are based more and more on the theory of descent.
Biologists endeavor to arrange animals on what is called the
41 natural system." No one now places whales among tish, bats
among birds, or shrews with mice, notwithstanding their ex-
ternal similarity ; and Darwin maintained that "community of
descent was the hidden bond which naturalists had been uncon-
sciously seeking.,, How else, indeed, can we explain the fact
that the framework of bones is so similar in the arm of a man,
the wing of a bat, the fore-leg of a horse, and the fin of a por-
poise— that the neck of a giraffe and that of an elephant con-
tain the same number of vertebras ?

Strong evidence is, moreover, afforded by embryology ; by
the presence of rudimentary organs and transient characters, as,
for instance, the existence in the calf of certain teeth which
never cut the gums, the shrivelled and useless wings of some
beetles, the presence of a series of arteries in the embryos of
the higher Vertebrata exactly similar to those which supply
the gills in fishes, even the spots on the young blackbird, the
stripes on the lion's cub; these, and innumerable other facts of
the same character, appear to be incompatible with the idea
that each species was specially and independently created ; and
to prove, on the contrary, that the embryonic stages of species
show us more or less clearly the structure of their ancestors.

Darwin's views, however, are still much misunderstood. I
believe there are thousands who consider that according to his
theory a sheep might turn into a cow, or a zebra into a horse.
No one would more confidently withstand any such hypothesis,
his view being, of course, not that the one could be changed
into the other, but that both are descended from a common
ancestor.

No one, at any rate, will question the immense impulse
which Darwin has given to the study of natural history, the
number of new views he has opened up, and the additional in-
terest which he has aroused in, and contributed to, Biology.
When we were young we knew that the leopard had spots, the
tiger was striped, and the lion tawny ; but why this was so it
did not occur to us to ask ; and if we had asked no one would
have answered. Now we see at a glance that the stripes of the
tiger have reference to its life among jungle-grasses ; the lion is
sandy, like the desert ; while the markings of the leopard re-
semble spots of sunshine glancing through the leaves. Again,
Wallace in his charming essays on natural selection has shown
how the same philosophy may be applied even to birds7 nests
— how, for instance, open nests have led to the dull color of
hen birds; the only British exception being the kingfisher,
iviich, as we know, nests in river-banks. Lower still, among
insects, Weismann has taught us that even the markings of

272 Sir John Lubbock's Address.

caterpillars are full of interesting lessons; while, in other cases,
specially among butterflies, Bates has made known to us the
cunous phenomena of mimicry.

The science of embryology may almost be said to have been
created in the last half-century. Fifty years ago it was a very
general opinion that animals which are unlike when mature,
were dissimilar from the beginning. It is to Von Baer, the
discoverer of the mammalian ovum, that we owe the great
generalization that the development of the egg is in the main a
progress from the general to the special, that zoological affinity
is the expression of similarity of development, and that the
different great types of animal structure are the result of dif-
ferent modes of development — in fact, that embryology is the
key to the laws of animal development

Thus the young of existing species resemble in many cases
the mature forms which flourished in ancient times. Huxley
has traced up the genealogy of the horse to the Miocene Anchi-
therium, and his views have since been remarkably confirmed
by Marsha discovery of the Pliohippus, Protohippus, Miohip-
pus and Mesohippus, leading down from the Eohippus of the
early Tertiary strata. In the same way Gaudry has called
attention to the fact that just as the individual stag gradually
acquires more and more complex antlers : having at first only
a single prong, in the next year two points, in the following
three, and so on ; so the genus, as a whole, in Middle Miocene
times, had two pronged horns ; in the Upper Miocene, three ;
and that it is not till the Upper Pliocene that we find any
species with the magnificent antlers of our modern deer. It
seems to be now generally admitted that birds have come down
to us through the Dinosaurians, and, as Huxley has shown, the
profound break once supposed to exist between birds and rep-
tiles has been bridged over by the discovery of reptilian birds
and bird-like reptiles ; so that, in fact, birds are modified rep-
tiles. Again, the remarkable genus Peripatus, so well studied
by Moseley, tends to connect the annulose and articulate types.
Again, the structural resemblances between Amphioxus and
the Ascidians had been pointed out byGoodsir; and Kowa-
levsky in 186.6 showed that these were not mere analogies, but
indicated a real affinity. These observations, in the words of
Allen Thomson, " have produced a change little short of revo-
lutionary in embryological and zoological views, leading as
they do to the support of the hypothesis that the Ascidian is
an earlier stage in the phylogenetic history of the mammal and
other vertebrates."

The larval forms which occur in so many groups, and of
which the Insects afford us the most familiar examples, are, it*
he words of Quatrefages, embryos, which lead an independen

Sir John LubbocWs Address. 278

life. In such cases as these external conditions act upon the
larvae as they do upon the mature form ; hence we have two
classes of changes, aaaptational or adaptive, and developmental.
These and many other facts must be taken into consideration ;
nevertheless naturalists are now generally agreed that embryo-
logical characters are of high value as guides in classification,
and it may, I think, be regarded as well-established that, just
as the contents and sequence of rocks teach us the past history
of the earth, so is the gradual development of the species indi-
cated b the structure of the embryo and its developmental
changes.

When the supporters of Darwin are told that his theory is
incredible, they may fairly ask why it is impossible that a
species in the course of hundreds of thousands of years should
have passed through changes which occupy only a few days or
weeks in the life-history of each individual ?

The phenomena of yolk-segmentation, first observed by
Prevost and Dumas, are now known to be in some form or
other invariably the precursors of embryonic development;
while they reproduce, as the first stages in the formation of the
higher animals, the main and essential features in the life-his-
tory of the lowest forms. The " blastoderm" as it is called,
or first germ of the embryo in the egg, divides itself into two
layers, corresponding, as Huxley has shown, to the two layers
into which the body of the Coelenterata may be divided. Not
only so, but most embryos at an early stage of development
have the form of a cup, the walls of which are formed by the
two layers of the blastoderm. Kowalevsky was the first to
show the prevalence of this embryonic form, and subsequently
Lankester and Haeckel put forward the hypothesis that it was
the embryonic repetition of an ancestral type, from which all
the higher forms are descended. The cavity of the cup is sup-
posed to be the stomach of this simple organism, and the open-
ing of the cup the mouth. The inner layer of the wall of the
cup constitutes the digestive membrane, and the outer the skin.
To this form Haeckel gave the name Grastraea. It is, perhaps,
doubtful whether the theory of Lankester and Haeckel can be
accepted in precisely the form they propounded it; but it has
had an important influence on the progress of embryology. I
cannot quit the science of embryology without alluding to the
very admirable work on u Comparative Embryology" by our
new general secretary, Mr. Balfour, and also the " Elements of
Embryology" which he had previously published in conjunc-
tion with Dr. M. Foster.

In 1842, Steenstrup published his celebrated work on the

"Alternation of Generations," in which he showed that many

species are represented by two perfectly distinct types or

274 Sir John Lubbock's Address.

broods, differing in form, structure and habits ; that in one of
them males are entirely wanting, and that the reproduction is
effected by fission, or by buds, which, however, are in some
cases structurally indistinguishable from eggs. Steenstrup's
illustrations were mainly taken from marine or parasitic species,
of very great interest, but not generally familiar, excepting to
naturalists. It has since been shown that the common Cynips
or Gallfly is also a case in point It had long been known that
in some genera belonging to this group, males are entirely
wanting, and it has now been shown by Bassett, and more
thoroughly by Adler, that some of these species are double-
brooded ; the two broods having been considered as distinct
genera.

Thus an insect known as Neuroterus lenticularis, of which
females only occur, produces the familiar oak-spangles so com-
mon on the under sides of oak leaves, from which emerge, not
Neuroterus lenticularts, but an insect hitherto considered as a
distinct species, belonging even to a different genus, Spathegasier
baccarum. In Spathegaster both sexes occur; they produce
the currant-like galls found on oaks, and from these galls Neu-
roterus is again developed. So also the King Charles oak-
apples produce a species known as Tei%as- terminalis, which
descends to the ground, and makes small galls on the roots of
the oak. From these emerge an insect known as Biorhiza
aplera, which again gives rise to the common oak-apple.

It might seem that such enquiries as these could hardly have
any practical bearing. Yet it is not improbable that they may
lead to very important results. For instance, it would appear
that the fluke which produces the rot in sheep, passes one pnase
of its existence in the black slug, and we are not without hopes
that the researches, in which our lamented friend Professor
Kolleston was engaged at the time of his death, which we all
so much deplore, will lead, if not to the extirpation, at any
rate to the diminution, of a pest from which our farmers have
so grievously suffered. It was in the year 1839 that Schwann
and Schleiden demonstrated the intimate relation in which ani-
mals and plants stand to each other, by showing the identity
of the laws of development of the elementary parts in the two
kingdoms of organic nature. Analogies indeed had been
previously pointed out, the presence of cellular tissue in cer-
tain parts of animals was known, but Caspar F. Wolffs bril-
liant, memoir had been nearly forgotten ; and the tendency of
microscopical investigation had rather been to encourage the
belief that no real similarity existed ; that the cellular tissue of
animals was essentially different from that of plants. This had
arisen chiefly, perhaps, because fully formed tissues were com-
pared, and it was mainly the study of the growth of cellsi

Sir John Lubbock's Address. 275

which led to the demonstration of the general law of develop-
ment for all organic elementary tissues.

As regards descriptive biology, by far the greater number of
species now recorded have been named and described within
the last half-century, and it is not too much to say that not a
day passes without adding new species to our lists. A compari-
son, for instance, of the edition of Cuvier's "Regne Animal,"
published in 1828, as compared with the present state of our
Knowledge, is most striking.

Dr. Giinther has been good enough to make a calculation for
me. The numbers, of course, are only approximate, but it
appears that while the total number of animals described up
to 1831 was not more than 70,000, the number now is at least
320,000.

Lastly, to show how large a field still remains for exploration,
I may add that Mr. Waterhouse estimates that the British
Museum alone contains not fewer than 12,000 species of insects
which have not yet been described, while our collections do not
probably contain anything like one-half of those actually in
existence. Further than this, the anatomy and habits even of
those which have been described offer an inexhaustible field for
research, and it is not going too far to say that there is not a
single species which would not amply repay the devotion of a
lifetime.

One remarkable feature in the modern progress of biological
science has been the application of improved methods of obser-
vation and experiment; and the employment in physiological
research of the exact measurements employed by the experi-
mental physicist. Our microscopes have been greatly improved : '
achromatic object-glasses were introduced by Lister in 1829 ;
the binocular arrangement by Wenham in 1856; while immer-
sion lenses, first suggested by Amici, and since carried out
under the formula of Abbe, are most valuable. The use of
chemical reagents in microscopical investigations has proved
most instructive, and another very important method of inves-
tigation has been the power of obtaining very thin slices by
imbedding the object to be examined in paraffin or some other
soft substance. In this manner we can now obtain, say, fifty
separate sections of the egg of a beetle, or the brain of a bee.

At the close of the last century, Sprengel published a most
suggestive work on flowers, in which he pointed out the curious
relation existing between these and insects, and showed that
the latter carried the pollen From flower to flower. His obser-
vations, however, attracted little notice, until Darwin called
attention to the subject in 1862. It had long been known that
the cowslip and primrose exist under two forms, about equally
Numerous, and aiffering from one another in the arrangements

276 Sir John Lubbock's Address.

of their stamens and pistils ; the one form having the stamens
on the summit of the flower and the stigma half-way down;
while in the other the relative positions are reversed, the stigma
being at the summit of the tube, and the stamens half-way
down. This difference had, however, been regarded as a case
of mere variability ; but Darwin showed it to be a beautiful
provision, the result of which is that insects fertilize each flower
with pollen brought from a different plant ; and he proved that
flowers iertilized with pollen from the other form yield more
seed than if fertilized with pollen from the same form, even if
taken from a different plant.

Attention having been thus directed to the question, an aston-.
ishing variety of most beautiful contrivances have been observed
and described by many botanists, especially Hooker, Axel,
Delpino, Hildebrand, Ben net, Fritz Miiller, and above all Her-
man Miiller and Darwin himself. The general result is that to
insects, and especially to bees, we owe the beauty of our gar-
dens, the sweetness of our fields. To their beueficent^ though
unconscious action, flowers owe their scent and color, their
honey — nay, in mauy cases, even their form. Their present
shape and varied arrangements, their brilliant colors, their
honey, and their sweet scent are all due to the selection exer-
cised by insects.

In these cases, the relation between plants and insects is one
of mutual advantage. In many species, however, plants pre-
sent us with complex arrangements adapted to protect them
from insects ; such, for instance, are in many cases, the resinous
glands which render leaves unpalatable; the thickets of hairs
and other precautions which prevent flowers from being robbed
of their honey by ants. Again, more than a century ago, our
countryman, Ellis, described an American plant, Dionaea, in
which the leaves are somewhat concave, with long lateral spines
and a joint in the middle ; close up with a jerk, like a rat-trap,
the moment any unwary insect alights on them. The plant, in
fact, actually captures and devours insects. This observation
also remained as an isolated fact until within the last few years,
when Darwin, Hooker, and others have shown that many other
species have curious and very varied contrivances for supplying
themselves with animal food.

As regards the progress of botany in other directions, Mr.
Thiselton Dyer has been kind enough to assist me in endeav-
oring to place the principal facts before you. Some of the
most fascinating branches of botany — morphology, histology,
and physiology scarcely existed before 1833. In the two for-
mer branches, the discoveries of von Mohl are preeminent
He first observed cell-division in 1835, and detected the pres-
ence of starch in chlorophyll-corpuscles in 1837, while he firet;

Sir John Lubbock's Address. 277

described protoplasm, now so familiar to us, at least by name,
in 1846. In the same year Amici discovered the existence of
the embryonic vesicle in the embryo sac, which develops into
the embryo when fertilized by the entrance of the pollen-tube
into the micropyle. The existence of sexual reproduction in
the lower plants was doubtful, or at least doubted by some
eminent authorities, as recently as 1853, when the actual pro-
cess of fertilization in the common bladderwrack of our shores
was observed by Thuret, while the reproduction of the larger
fungi was first worked out by De Bary in 1863.

As regards lichens, Schwendener proposed, in 1869, the
startling theory, now, however, accepted by some of the high-
est authorities, that lichens are not autonomous organisms, but
commensal associations of a fungus parasitic on an alga. With
reference to the higher Cryptogams it is hardly too much to
say that the whole of our exact knowledge of their life-his-
tory has been obtained during the last half-century. Thus in
the case of ferns the male organs, or antheridia, were first dis-
covered by Nageli in 1844, and the archegonia, or female
organs, by Saminski, in 1848. The early stages in the devel-
opment of mosses were worked out by Valentine in lb33.
Lastly, the principle of Alternation of Generations in plants
was discovered by Hofmeister. This eminent naturalist also,
in 1851-4, pointed out the homologies of the reproductive pro-
cesses in mosses, vascular cryptogams, gymnosperms, and
angiosperms.

Geographical Botany can hardly be said to have had any
scientific status anterior to the publication of the u Origin of
Species." The way had been paved, however, by A. de Can-
dolle and the well-known essay of Edward Forbes — "On the
Distribution of the Plants and Animals of the British Isles," —
by Sir J. Hooker's introductory essay to the "Flora of New
Zealand," and by Hooker and Thomson's introductory essay to
the "Flora Indica." One result of these researches has been to
give the coup-de-grdce to the theory of an Atlantis. Lastly, in
a lecture delivered to the Geographical Society in 1878, This-
elton Dyer himself has summed up the present state of the sub-
ject, and contributed an important addition to our knowledge
of plant-distribution by showing how its main features may be
explained by migration in longitude from north to south with-
out recourse being had to a submerged southern continent for
explaining the features common to South Africa, Australia
and America.

The fact that systematic and geographical botany have claimed
a preponderating share of the attention of British phytologists,
Js no doubt in great measure due to the ever-expanding area
°f the British Empire, and the rich botanical treasures which

278 Sir John Lubbock's Address.

we are continually receiving from India and our numerous col-
onies. The series of Indian and Colonial Floras, published
under the direction of the authorities at Kew, and the "Genera
Plantarum " of Bentham and Hooker, are certainly an honor to
our country. To similar causes we may trace the rise and
rapid progress of economic botany, to which the late Sir W.
Hooker so greatly contributed.

In vegetable physiology some of the most striking researches
have been on the effect produced by rays of light of different
refrangibility. Daubeny, Draper and Sachs have shown that
the light of the red end of the spectrum is more effective than
that of the blue, so far as the decomposition of carbon dioxide
(carbonic acid) is concerned.

Nothing could have appeared less likely than that researches
into the theory of spontaneous generation should have led to
practical improvements in medical science. Yet such has been
the case. Only a few years ago Bacteria seemed mere scientific
curiosities. It had long been known that an infusion — say, of
hay — would, if exposed to the atmosphere, be found, after a
certain time, to teem with living forms. Even those few who
still believe that life would be spontaneously generated in such*
an infusion, will admit that these minute organisms are, if not
entirely, yet mainly, derived from germs floating in our atmos-
phere ; and if precautions are taken to exclude such germs, as
in the careful experiments especially of Pasteur, Tyndall, and
Eoberts, every one will grant that in ninety-nine cases out of a
hundred no such development of life will take place. In
1836-7 Cagniard de la Tour and Schwann independently
showed that fermentation was no mere chemical process, but
was due to the presence of a microscopic plant. But, more
than this, it has been gradually established that putrefaction is
also the work of microscopic organisms.

These facts have led to most important results in Surgery.
One reason why compound fractures are so dangerous, is be-
cause, the skin being broken, the air obtains access to the
wound, bringing with it innumerable germs, which too often
set up putrefying action. Lister first made a practical applica-
tion of these observations. He set himself to find some sub-
stance capable of killing the germs without being itself too
potent a caustic, and he found that dilute carbolic acid fulfilled
these conditions. This discovery has enabled many operations
to be performed which would previously have been almost
hopeless.

The same idea seems destined to prove as useful in Medicine
as in Surgery. There is great reason to suppose that many dis-
eases, especially those of a zymotic character, have their origin
in the germs of special organisms. We know that fever runs a

Sir John LxtbbocKs Address. 279

certain definite course. The parasitic organisms are at first few,
but gradually multiply at the expense of the patient, and then
die out again. Indeed, it seems to be thoroughly established
that many diseases are due to the excessive multiplication of
microscopic organisms, and we are not without hope that means
will be discovered by which, without injury to the patient,
these terrible, though minute, enemies may be destroyed, and
the disease thus stayed. Bacillus anthracis, for instance, is
now known to be the cause of splenic fever, which is so fatal
to cattle, and is also communicable to man. At Bradford, for
instance, it is only too well-known as the woolsorter's disease.
If, however, matter containing the Bacillus be treated in a par-
ticular manner, and cattle be then inoculated with it, they are
found to acquire an immunity from the fever. The interesting
researches of Burdon Sanderson, Greenfield, Koch, Pasteur,
Toussaint, and others, seem to justify the hope that we may be
able to modify these and other germs, and then by appropriate
inoculation to protect ourselves against fever and other acute
diseases.

The history of Anaesthetics is a most remarkable illustration
how long we may be on the very verge of a most important
discovery. Ether, which, as we all know, produces perfect
insensibility to pain, was discovered as long ago as 1540. The
anaesthetic property of nitrous oxide, now so extensively used,
was observed in 1800 by Sir H. Davy, who actually experi-
mented on himself, and had one of his teeth painlessly ex-
tracted when under its influence. He even suggests that "as
nitrous oxide gas seems capable of destroying pain, it could
probably be used with advantage in surgical operations." Nay,
this property of nitrous oxide was habitually explained and
illustrated in the chemical lectures given in hospitals, and yet
for fifty years the gas was never used in actual operations. No
one did more to promote the use of anaesthetics than Sir James
Y. Simpson, who introduced chloroform, a substance which was
discovered in 1831, and which for a while almost entirely super-
seded ether and nitrous oxide, though, with improved methods
of administration, the latter are now coming into favor again.

The only other reference to Physiology which time permits
me to make, is the great discovery of the reflex action, as it is
called, of the nervous centres. Keflex actions had been long
ago observed, and it was known that they were more or less
independent of volition. But the general opinion was that these
movements indicated some feeble power of sensation independ-
ently of the brain, and it was not till the year 1832 that the
" reflex action ,; of certain nervous centres was made known to
us by Marshall Hall, and almost at the same period by Johan-
nes Miiller.

Am. Jour. Sci.— Third Series, Vol. XXII, No. 130.— October, 1881.
19

280 Sir John Lubbock? s Address.

Few branches of science have made more rapid progress in
the last half-century than that which deals with the ancient
condition of man. When our Association was founded it was
generally considered that the human race suddenly appeared on
the scene, about 6,000 years ago, after the disappearance of the
extinct mammalia, and when Europe, both as regards physical
conditions and the other animals by which it was inhabited,
was pretty much in the same condition as in the period covered
by Greek and Eoman history. Since then the persevering
researches of Layard, Eawlinson, Botta and others have made
known to us, not only the statutes and palaces of the ancient
Assyrian monarch, but even their libraries; the cuneiform
characters have been deciphered, and we can not only see, but
read in the British Museum, the actual contemporary records,
on burnt clay cylinders, of the events recorded in the historical
books of the Old Testament and in the pages of Herodotus.
The researches in Egypt also seem to have satisfactorily estab-
lished the fact that the pyramids themselves are at least 6,000
years old, while it is obvious that the Assyrian and Egyptian
monarchies cannot suddenly have attained to the wealtn and
power, the state of social organization, and progress in the arts,
of which we have before us, preserved by the sand of the desert
from the ravages of man, such wonderful proofs.

In Europe, the writings of the earliest historians and poets
indicated that, before iron came into general use, there was a
time when bronze was the ordinary material of weapons, axes,
and other cutting implements, and though it seemed d priori
improbable that a compound of copper and tin should have
preceded the simple metal iron, nevertheless the researches of
archaeologists have shown that there really was in Europe a
"Bronze Age," which at the dawn of history was just giving
way to that of "Iron."

The contents of ancient graves, buried in many cases so that
their owner might carry some at least of his wealth with him
to the world of spirits, have proved very instructive. More
especially the results obtained by Nilsson in Scandinavia, by
Hoare and Borlase, Bateman and Grreenwell, in our own coun-
try, and the contents of the rich cemetery at Hallstadt, left no
room for doubt as to the existence of a Bronze Age ; but we
get a completer idea of the condition of Man at this period
from the Swiss lake-villages, first made known to us by Iteller,
and subsequently studied by Morlot, Troyon, Desor, Rutimeyer,
Heer, and other Swiss archaeologists. Along the shallow edges
of the Swiss lakes there flourished, once upon a time, many
populous villages or towns, built on platforms supported by
piles, exactly as many Malayan villages are now. Under these
circumstances innumerable objects were one by one dropped

Sir John Lubbock's Address. 281

into the water; sometimes whole villages were burnt, and their
contents submerged ; and thus we have been able to recover,
from the waters of oblivion in which they had rested for more
than 2,000 years, not only the arms and tools of this ancient
people, the bones of their animals, their pottery and orna-
ments, but the stuffs they wore, the grain they had stored up
for future use, even fruits and cakes of bread.

But this bronze-using people were not the earliest occupants
of Europe. The contents of ancient tombs give evidence of
a time when metal was unknown. This also was confirmed
bjT the evidence then unexpectedly received from the Swiss
lakes. By the side of the bronze-age villages were others, not
less extensive, in which, while implements of stone and bone
were discovered literally by thousands, not a trace of metal
was met with. The shell-mounds or refuse-heaps accumulated
by the ancient fishermen along the shores of Denmark, and
carefully examined by Steenstrup, Worsaae, and other Danish
naturalists, fully confirmed the existence of a " Stone Age."

We have still much to learn, I need hardly say, about this
Stone-age people, but it is surprising how much has been made
out. Evans truly observes, in his admirable work on "Ancient
Stone Implements," " that so far as external appliances are con-
cerned, they are almost as fully represented as would be those
of any existing savage nation by the researches of a painstak-
ing traveler." We nave their axes, adzes, chisels, borers,
scrapers, and various other tools, and we know how they made
and how they used them ; we have their personal ornaments
and implements of war ; we have their cooking utensils; we
know what they ate and what they wore ; lastly, we know
their mode of sepulture and funeral customs. They hunted
the deer and horse, the bison and urus, the bear and the wolf,
but the reindeer had already retreated to the North.

No bones of the reindeer, no f ragmen t of any of the extinct mam-
malia, have been found in any of the Swiss lake-villages or in
any of the thousands of the tumuli which have been opened in
our own country or in Central and Southern Europe. Yet the
contents of caves and of river-gravels afford abundant evidence
that there was a time when the mammoth and rhinoceros, the
musk-ox and reindeer, the cave lion and hyena, the great bear
and the gigantic Irish elk wandered in our woods ;md valleys,
and the nippopotamus floated in our rivers; when England
.and France were united, and the Thames and the Ehine had a
common estuary. This was long supposed to be before the
advent of man. At length, however, the discoveries of Bou-
cher de Perthes in the valley of the Somme, supported as they
are by the researches of many continental naturalists, and in
our own country of MacEnery and Godwin- Austen, Prestwich

282 Sir John Lubbock's Address.

and Lyell, Vivian and Pengelly, Christy, Evans and many
more, have proved that man formed a humble part of this
strange assembly.

Nay, even at this early period there were at least two dis-
tinct races of men in Europe ; one of them — as Boyd Daw-
kins has pointed out — closely resembling the modern Esqui-
maux in form, in his weapons and implements, probably in
his clothing, as well as in so many of the animals with which
he was associated.

At this stage Man appears to have been ignorant of pottery,
to have had no knowledge of agriculture, no domestic ani-
mals, except perhaps the dog. His weapons were the axe, the
spear, and the javelin ; I do not believe he knew the use of
the bow, though he was probably acquainted with the lance.
He was, of course, ignorant of metal, and his stone implements,
though skilfully formed, were of quite different shapes from
those of the second Stone age, and were never ground. This
earlier Stone period, when man coexisted with these extinct
mammalia, is known as Palaeolithic, or Early Stone Age, in
opposition to the Neolithic, or Newer Stone Age.

The remains of the mammalia which coexisted with man in
pre-historie times have been most carefully studied by Owen,
Lartet, Eiitimeyer, Falconer, Busk, Boyd-Dawkins, and others.
The presence of the mammoth, the reindeer, and especially of
the musk-ox, indicates a severe, not to say an arctic, climate,
the existence of which, moreover, was proved by other consid-
erations ; while, on the contrary, the hippopotamus requires
considerable warmth. How then is this association to be
explained ?

While the climate of the globe is, no doubt, much affected
by geographical conditions, the cold of the glacial period was,
I believe, mainly due to the eccentricity of the earth's orbit
combined with the obliquity of the ecliptic. The result of the
latter condition is a period of 21,000 years, during one-half of
which the northern hemisphere is warmer than the southern,
while during the other 10,500 years the reverse is the case. At
present we are in the former phase, and there is, we know, a
vast accumulation of ice at the south pole. But when the eartn's
orbit is nearly circular, as it is at present, the difference
between the two hemispheres is not very great ; on the con-
trary, as the eccentricity of the orbit increases the contrast
between them increases also. This eccentricity is continually
oscillating between certain limits, which Croll and subsequently
Stone have calculated out for the last million years. At
present the eccentricity is *016 and the mean tempera-
ture of the coldest month in London is about 40°.
Such has been the state of things for nearly 100,000 years;

Sir John Lubbock's Address. 283

but before that there was a period, beginning 300,000 years
ago, when the eccentricity of the orbit varied from *26 to *57.
The result of this would be greatly to increase the efi'ect due
to the obliquity of the orbit; at certain periods the climate
would be much warmer than at present, while at others the
number of days in winter would be twenty more, and of sum-
mer twenty less than now, while the mean temperature of the
coldest month would be lowered 20°. We thus get something
like a date for the last glacial epoch, and we see that it was
not simply a period of cold, but rather one of extremes, each
beat of the pendulum of temperature lasting for no less than
21,000 years. This explains the fact that, as Morlot showed in
1854, the glacial deposits of Switzerland, and, as we now know,
those of Scotland, are not a single uniform layer, but a succes-
sion of strata, indicating very different conditions. I agree
also with Croll and Geikie in thinking that these considera-
tions explain the apparent anomaly of the coexistence in the
same gravels of arctic and tropical animals ; the former hav-
ing lived in the cold, while the latter flourished in the hot,
periods.

It is, I think, now well established that man inhabited
Europe during the milder periods of the glacial epoch. Some
high authorities,. indeed, consider that we have evidence of his
presence in pre-glacial and even in Miocene times, but I con-
fess that I am not satisfied on this point. Even the more
recent period carries back the record of man's existence to a
distance so great as altogether to change our views of ancient
historv.

Nor is it only as regards the antiquity and material condi-
tion of man in prehistoric times that great progress has been
made. If time permitted, I should have been glad to have
dwelt on the origin and development of language, of custom,
and of law. On all of these the comparison of the various
lower races still inhabiting so large a portion of the earth's
surface, has thrown much light; while even in the most culti-
vated nations we find survivals, curious fancies, and lingering
ideas; the fossil remains, as it were, of former customs and
religions embedded in our modern civilization, like the relics
of extinct animals in the crust of the earth.

In geology the formation of our Association coincided withv
the appearance of Lyell's "Principles of Geology," the first
volume of which was published in 1830 and the second in 1832.
At that time the received opinion was that the phenomena of
Geology could only be explained by violent periodical convul-
sions, and a high intensity of terrestrial energy culminating in
repeated catastrophes. Hutton and Playfair had indeed main-

284 Hir John Lubbock's Address.

tained that such causes as those now in operation, would, if
only time enough were allowed, account for the geological
structure of the earth ; nevertheless the opposite view generally
prevailed, until Lyell, with rare sagacity and great eloquence,
with a wealth of illustration and most powerful reasoning, con-
vinced geologists that the forces now in action are powerful
enough, if only time be given, to produce results quite as
stupendous as those which Science records.

As regards stratigraphical geology, at the time of the first
meeting of the British Association at York, the strata between
the carboniferous limestone and the chalk hud been mainly
reduced to order and classified, chiefly through the labors of
William Smith. But the classification of all the strata lying
above the chalk and below the carboniferous limestone respec-
tively, remained in a state of the greatest confusion. The year
1831 marks the period of the commencement of the joint labors
of Sedgwick and Murchison, which resulted in the establish-
ment of the Cambrian, Silurian, and Devonian systems. Our
Pre-Cambrian strata have recently been divided by Hicks into
four great groups of immense thickness, and implying, there-
fore, a great lapse of time ; but no fossils have yet been discov-
ered in them. LyelFs classification of the Tertiary deposits;
the result of the studies which he carried on with the assistance
of Deshayes and others, was published in the third volume of
the u Principles of Geology " in 1833. The establishment of
LyelPs divisions of Eocene, Miocene and Pliocene, was the
starting-point of a most important series of investigatipns by
Prestwich and others of these younger deposits; as well as of
the Post-tertiary, Quaternary, or drift beds, which are of special
interest from the light they have thrown on the early history of
man.

A full and admirable account of what has recently been
accomplished in this department of science, especially as re-
gards the paleozoic rocks, will be found in Etheridge's late
address to the Geological Society.

Before 1831 the only geological maps of this country were
William Smith's general and county maps, published between
the years 1815 and 1824. In the year 1832 De la Beche made
proposals to the Board of Ordnance to color the ordnance-maps
geologically, and a sum of SOOL was granted for the purpose.
Out of this small beginning grew the important work of the
Geological Survey.

The cause of slaty cleavage had long been one of the great
difficulties of geology. Sedgwick suggested that it was pro-
duced by the action of crystalline or polar forces. According
to this view miles and miles of country, comprising great moun-
tain masses, were neither more nor less than parts of a gigantic

Sir John LuhbocKs Address. * 285

crystal. Sharpe, however, called attention to the fact that
shells and other fossils contained in slate rocks are compressed
in a direction at right angles to the planes of cleavage, as if the
rocks had been seized in the jaws of a gigantic vise. Sorby
first maintained that the cleavage itself was due to pressure.
He observed slate rocks containing small plates of mica, and
that the effect of pressure would tend to arrange these plates with
their flat surfaces perpendicular to the direction of the pressure.
Tyndall has since shown that the presence of flat flakes is not
necessary. He proved by experiment that pure wax could be
made by pressure to split into pieces of great tinuity, which he
attributes mainly to the lateral sliding of the particles of the
wax over each other ; and thus the result of pressure on such a
mass is to develop a fissile structure similar to that produced in
wax on a small scale, or on a great one in the slate rocks of
Cumberland or Wales.

The difficult problem of the conditions under which granite
and certain other rocks were formed was attacked by Sorby
with great skill in a paper read before the Geological Society
in 1858. The microscopic hollows in many minerals contain a
liquid which does not entirely fill the hollow, but leaves a small
vacuum ; and Sorby ingeniously pointed out that the rock
must have solidified at least at a temperature high enough to
expand the liquid so as to fill the cavity. Sorby's important
memoir laid the foundation of microscopic petrography, which
is now not only one of the most promising branches of geologi-
cal research, but which has been successfully applied by Sorby
himself, and by Maskelyne, to the study of meteorites.

As regards the physical character of the earth, two theories
have been held : one, that of a fluid interior covered by a thin
crust; the other, of a practically solid sphere. The former is
now very generally admitted, both by astronomers and geol-
ogists, to be untenable. The prevailing feeling of geologists on
this subject has been well expressed by Professor LeConte,
who says, " the whole theory of igneous agencies — which is little
less than the whole foundation of theoretic geology — must be
reconstructed on the basis of a solid earth."

In 1837 Agassiz startled the scientific world by his u Discours
sur Tancienne extension des Glaciers," in which, developing the
observation already made by Charpentier and Venetz, that
bowlders had been transported to great distances, and that rocks
far away from, or high above, existing glaciers, are polished
and scratched by the action of ice, he boldly asserted the exist-
ence of a "glacial period," during which Switzerland the North
of Europe were subjected to great cold and buried under a vast
sheet of ice.

The ancient poets described certain gifted mortals as privi-

286 * Sir John Lubbock's Address.

leged to descend into the interior of the earth, and have
exercised their imagination in recounting the wonders there
revealed. As in other cases, however, the realities of science
have proved more varied and surprising than the dreams of
fiction. Of the gigantic and extraordinary animals thus re-
vealed to us by far the greatest number have been described
during the period now under review. For instance, the gigan-
tic Cetiosaurus was described by Owen in 1838, theDinornis of
New Zealand by the same distinguished naturalist in 1839, the
Mylodon in the same year, and the Archaeopteryx in 1862.

In America, a large number of remarkable forms have been
described, mainly by Marsh, Leidy and Cope. Marsh has made
known to us the Titanosaurus, of the American (Colorado)
Jurassic beds, which is, perhaps, the largest land animal yet
known, being a hundred feet in length, and at least thirty in
height, though it seems possible that even these vast dimen-
sions were exceeded by those of the Atlantosaurus. Nor must
I omit the Hesperornis, described by Marsh in 1872, as a car-
nivorous, swimming ostrich, provided with teeth, which he
regards as a character inherited from reptilian ancestors ; the
Ichthyornis, stranger still, with biconcave vertebrae, like those
of fishes, and teeth set in sockets ; while in the Eocene deposits
in the Eocky Mountains the same indefatigable paleontologist,
among other very interesting remains, has discovered three
new groups of remarkable mammals, the Dinocerata, Tillodon-
tia, and Brontotheridae. He has also described a number of
small, but very interesting, Jurassic mammalia, closely related
to those found in our Stonesfield Slate and Purbeck beds, for
which he has proposed a new order, " Prototheria." Lastly, I
may mention the curiously anomalous Reptilia from South
Africa, which have been made known to us by Professor
Owen.

Another important result of recent paleontological research
is the law of brain-growth. It is not only in the higher mam-
malia that we find forms with brains much larger than any
existing, say, in Miocene times. The rule is almost general
that — as Marsh has briefly stated it — u all tertiary animals
had small brains." We may even carry the generalization
further. The Cretaceous birds had brains one-third smaller
than those of our own day, and the brain-cavities of the Dino-
sauria of the Jurassic period, are much smaller than in any
existing reptiles.

As giving, in a few words, an idea of the rapid progress in
this department, I may mention that Morris's " Catalogue of
British Fossils," published in 1843, contained 5,300 species;
while that now in preparation by Mr. Etheridge enumerates
15,000,

Sir John Lubbock's Address. 287

But if these figures show how rapid our recent progress
has been, they also very forcibly illustrate the imperfection
of the geological record, and give us, I will not say a meas-
ure, but an idea, of the imperfection of the geological record.
The number of all the described recent species is over 300,000,
but certainly not half are yet on our lists, and we may safely
take the total number of recent species as being not less than
700,000. But in former times there have been at the very
least twelve periods, in each of which by far the greater num-
ber of species were distinct. True the number of species was
probably not so large in the earlier periods as at present; but
if we make a liberal allowance for this, we shall have a total
of more than 2,000,000 species, of which about 25,000 only are
as yet upon record ; and many of these are only represented by
a few, some only by a single specimen, or even only by a
fragment.

The progress of paleontology may also be marked by the
extent to which the existence of groups has been, if I may so
say, carried back in time. Thus I believe that in 18304lthe
earliest known quadrupeds were small marsupials belonging to
the Stonesfield slates ; the most ancient mammal now known is
liicrolestes antiquus from the Keuper of Wiirtemberg; the
oldest bird known in 1831 belonged to the period of the Lon-
don Clay, the oldest now known is the Arcbaeopteryx of the
Solenhofen slates, though it is probable that some at any rate
of the footsteps on the Triassic rocks are those of birds. So
again the Amphibia have been carried back from the Trias to
Coal-measures ; Fish from the Old Bed Sandstone to the Upper
Silurian ; Beptiles to the Trias ; Insects from the Cretaceous
to the Devonian ; Mollusca and Crustacea from the Silurian to
the Lower Cambrian. The rocks below the Cambrian, though
of immense thickness, have afforded no relics of animal life,
if we except the problematical Eozoon Canadense, so ably
studied by Dawson and Carpenter. But if paleontology as
yet throws no light on the original forms of life, we must
remember that the simplest and the lowest organisms jire so soft
and perishable that they would leave u not a wrack behind. "
I will not, however, enlarge on this branch of science, because
we shall have the advantage on Friday of hearing it treated
with the skill of a master.

Passing the Science of Geography, Mr. Clements Markham
has recently published an excellent summary of what has
been accomplished during the half-century.

As regards the Arctic regions, in the year 1830 the coast
line of Arctic America was only very partially known, the
region between Barrow Strait and the continent, for instance,

288 Sir John Lubbock's Address.

being quite unexplored, while the eastern sides of Green-
land and Spitzbergen, and the coasts of Nova Zerabla were
almost unknown. Now the whole coast of Arctic America has
been delineated, the remarkable archipelago to the north has
been explored, and no less than seven northwest passages —
none of them, however, of any practical value — have been
traced. The northeastern passage, on the other hand, so far
at least as the mouths of the great Siberian rivers, may per-
haps hereafter prove of commercial importance. In the Ant-
arctic regions, Enderby and Graham Lands were discovered in
1831-2, Balleny Islands and Sabrina Land in 1839, while the
fact of the existence of the great southern continent was estab-
lished in 1841 by Sir James Eoss, who penetrated in 1842 to
78° ll7, the southe'rnmost point ever reached.

In Asia, to quote from Mr. Markham, "our officers have
mapped the whole of Persia and Afghanistan, surveyed Mesopo-
tamia, and explored the Pamir steppe. Japan, Borneo, Siam,
the Malay peninsula, and the greater part of China have been
brought more completely to our knowledge. Eastern Turke-
stan has been visited, and trained native explorers have pene-
trated to the remotest fountains of the Oxus, and the wild
plateaus of Tibet. Over the northern half of the Asiatic Con-
tinent the Eussians have displayed great activity. They have
traversed the wild steppes and deserts of what on old atlases
was called Independent Tartary, have surveyed the courses of
the Jaxartes, the Oxus and the Amur, and have navigated the
Caspian and the Sea of Aral. They have pushed their scien-
tific investigations into the Pamir and Eastern Turkestan,
until at last the British and Eussian surveys have been con-
nected. "

Again, fifty years ago the vast Central Eegions of Africa
were almost a blank upon our best maps. The rudely drawn
lakes and rivers in maps of a more ancient date had become
discredited. They did not agree among themselves, the evi-
dence upon which they were laid down could not be found,
they were in many respects highly improbable, and they seemed
inconsistent with what had then been ascertained concerning
the Niger and the Blue and White Niles. Atthe date of which
I speak, the Sahara had been crossed by English travelers from
the shore of the Mediterranean: but the southern desert still
formed a bar to travelers from the Cape, while the accounts of
traders and others who alone had entered the country from
the eastern and western coasts were considered to form an insuf-
ficient basis for a map.

Since that time the successful crossing of the Kalahari des-
ert to Lake Ngami has been the prelude to an era of African
discovery. Livingston explored the basin of the Zambesi, and

C. G. Rockwood — Notes on Earthquakes. 289

discovered vast lakes and waters which have proved to be those
of the higher Congo. Burton and Speke opened the way from
the West Coast, which Speke and Grant pursued into and down
the Nile, and Stanley down the course of the middle and lower
Congo; and the vast extension of Egyptian dominion has
brought a huge slice of equatorial Africa within the limits of
semi-civilization. The western side of Africa has been attacked
at many points. Alexander and Galton were among the first
to make known to us its western tropical regions immediately
to the north of the Cape Colony ; the Ogow£ has been explored ;
the Congo promises to become a center of trade, and the navi-
gable portions of the Niger, the Gambia, and the Senegal are
familiarly known.

The progress of discovery in Australia "has been as remark-
able as that in Africa. The interior of this great continent
was absolutely unknown to us fifty years ago, but is now
crossed through its center by the electric telegraph, and no
inconsiderable portion of it is- turned into sheep-farms. It is
an interesting fact that General Sabine, so long one of our most
active officers, and who is still with us, though, unfortunately,
his health has for some time prevented him from attending our
meetings, was born on the very day that the first settler landed
in Australia.

[To be continued.]

Art. XL. — Notes on Earthquakes ; by C. G. Eockwood.

The Scio Earthquake. — In April last the Island of Scio and
its vicinity were shaken by an earthquake which* caused great
loss of life and property and proved to be the beginning of
quite an extended series of shocks. This Island lies off the
Gulf of Smyrna in the Grecian Archipelago and is about
thirty-two miles long north and south, by about eighteen miles
wide. It is separated from the mainland by a strait seven or
eight miles wide and had about 50,000 inhabitants. The first
and most violent shock occurred at 1.40 P. M. on Sunday, April
3d, and lasted ten seconds. It was followed by a second at 2
p. M. and a third at 3 P. M. of the same day. The ground was
then quiet until sunset, when the shaking recommenced and
continued with such frequency that up to April 5th two hun-
dred and fifty shocks had been counted; of which thirty or
forty were of sufficient strength to overthrow walls. Other
shocks, often severe, occurred from time to time up to May
20th. An especially severe one, lasting four seconds, occurred
on April 11th. The violent shocks with which the disturbance

290 C. O. Roekwood — Note* on Earthquakes.

begun, destroyed many village*, and especially damaged the
city of Scio or Kastro, on the east coast, the chief town of the
island It was estimated that in all the southern part of the
island certainly nine-tenths of the houses would have to be re-
built and some whole villages were reduced to simple masses
of ruins. The loss of life was at first estimated as high as
10,000, but later advices render it probable that not more than
3000 or 4000 were killed. The consequent suffering and
destitution were, however, so great that contributions were
made in various countries of Europe and America for the
relief of the survivors. The center of disturbance appears to
have been under the eastern part of the island and the vibra-
tions were felt with destructive effect at Tchisme and at
Smyrna on the mainland to the eastward, and Euboea and the
islands of Tinos and Syra to the westward. The direction of
vibration was east and west, as is shown not only by numerous

(>ersonal reports, but by the direction of the cracks in the
)roken walls.

Die Vulkanischen Ereignisse des JaJtres 1880. — The Sixteenl/i
Annual Report of Dr. C. W. C. Fuchs (Mineralog. u. Petrograph.
MittbeiL, W ien.) is at hand and presents some points of interest

The volcanic activity of the year was less than usual, no
great eruption having occurred anywhere. From Vesuvius
small streams of lava issued in February and toward the end of
July, and again in September, October and November. So also
Etna showed some activity in February which lasted until May,
consisting, however, mostly of showers of ashea Other eruptive
phenomena were the sand shower in St Domingo on January
4, the elevation of the Island in Lake Uopango in January, the
eruption of Fuego in Guatemala June 29,-and the eruption of
Mauna Loa Nov. 5.

Earthquakes are recorded to the number of 225, of which 65
are American, showing that the deficiency of such items in
previous reports was due, as was supposed, to want of full
information, and not to any dearth of such phenomena upon
the Western continent. Of these 65, all but one have already
been noted in this Journal. The earthquakes of the year were
divided among the seasons as follows:

Winter, 80— Dee. 43, Jan. 18, Feb. 19;

Spring, 32 — March 15, April 9, May, 8;

Summer, 59 — June 10, July 28, August 21 ;

Autumn, 54 — Sent. 14, Oct. 9, Nov. 31.

On thirty-three days in the year shocks occurred at two or
more distant places, and thirty-two places were affected at
two or more times. A few earthquakes are of sufficient in-
terest to merit more special notice.

G. G. Rockwood — Notes on Earthquakes. 291

Those of San Salvador in January and February, in Cuba,
Florida and Mexico in the latter part of January, and the
destructive shocks in the Philippines in July, have already
been mentioned in this Journal.

On November 9, the city of Agram, after numerous less
important shakings during the summer, was affected by a vio-
lent earthquake, which extended over Croatia, Montenegro,
and a great part of Hungary and Bosnia, and even to Bohemia
and upper Italy. This, the most severe shock, was followed
by numerous others in gradually decreasing intensity, so that
up to the 18th December, 61 distinct shocks had been observed
in the city, with minor vibrations innumerable. The city
appears to have suffered frequently in the past, as a list is
given of 33 earthquakes which have occurred there since 1502.
The author remarks on the continuance of the subterranean
noises when the shocks had ceased and the ground was at rest
The phenomena still continued at the end of the year.

On July 4 all Switzerland was shaken by an earthquake,
which had its origin in the neighborhood of the Simplon.

Smyrna and its vicinity suffered on the 22d of June, and
again on the 29th of July, when the shocks extended to the
neighboring islands and did much damage. In Smyrna itself
one hundred houses were overthrown and thirty persons were
killed. The centre of disturbance was in the mountains north-
east of the city, where the village of Menemen was left unin-
habitable. This earthquake has been described in the French
scientific journals. This same region has again been shaken
by the Scio earthquake of 1881, as mentioned above.

On September 2d an earthquake at Kalavrita, in the Pelo-
ponnesus, was felt also on the other side of the Mediterranean
at Tripoli, in Africa.

Dr. Fuchs records some observations on the slight vibrations
which Prof. Perrey has reported as occurring frequently in
Nice. They are only perceptible at night when all is still, and
he is inclined to refer them to the dashing of the waves upon
the shore, although he states that the intensity of the vibration
does not correspond to that of the wave action, nor yet do the
intervals between the vibrations correspond to the intervals
between the waves. He suggests that the direction in which
the waves strike may have influence on the phenomena.

C. G. R.

292 A. E. Verrill — Marine Fauna occupying the outer banks

Art. XLL — Notice of the remarkable Marine Fauna occupying
tlie outer banks off the Southern coast of New England. No. 2 ;
by A. E. Verrill. (Brief Contributions to Zoology from
the Museum of Yale College : No. XL VIII.)

The U. S. Fish Commission has occupied, this season, the
station at Wood's Holl,* Mass., on Vineyard Sound, where a
laboratory for its use was established in 1875.

The shallower waters of that region had been very fully ex-
plored by the Fish Commission in 1871 and 1875. Neverthe-
less, much has been done this year toward completing the inves-
tigation of the surface fauna, which is exceedingly rich and
varied at Wood's Holl. The larval forms of Crustacea, annel-
ida, echinodermata, mollusca, etc., have been taken in large
numbers in the towing nets, as well as adult forms of many
kinds, including, especially, numerous species of Syllidae, many
of which are new.

The special subject for investigation this year, was, however,
the rich fauna that was last year discovered in deep water, about
75 to 120 miles off the southern coast of New England, near the
edge of the Gulf Stream. A brief account of our discoveries in
that region last season was published by me in this Journal
(vol. xx, p. 390), with notices and descriptions of many of the
mollusca and echinoderms then discovered. A more detailed
account of the mollusca was published by me in the Proceed-
ings of the National Museum (vol. iii, pp. 356-409, Dec -Jan.).
Professor S. I. Smith published an account of the Crustacea in
the same Proceedings (vol. iii, pp. 413-452, Jan., 1881).

In the following articles I propose to notice some of the
more interesting species, whether obtained this year or last
year. Some of these species were also dredged on the 16th
of last November, by Lieut. Z. L. Tanner, in a trip made to
the deep water off the mouth of Chesapeake Bay, after the
regular dredging operations of the season had ceased.

As many of the species there obtained are referred to, a list
of the stations is here added :

atlon.

Locality.
N. Lat. W. Long.

Fathoms.

Bottom.

896

37° 26' 74° 19'

sand, shells

897

37 25 74 18

157|

nand, mud.

898

37 24 74 17

300

mud.

899

37 22 74 29

57*

sand.

900

37 19 74 41

sand.

901

37 10 75 08

sand.

Our dredging* this year, in deep water, have also been made
with the " Fish Hawk/' Lieut. Z. L. Tanner, commander. Mr.

* Formerly written " Wood's Hole," but the name was changed by an act of
the Legislature of Massachusetts, in 1875.

off the Southern coast of New England. 293

A. P. Chapin, of Warsaw, N. Y., made the temperature obser-
vations and records of soundings, etc.

The party immediately associated with the writer in the
zoological investigations consisted of Professor S. I. Smith and
Mr. J. H. Emerton (artist), of Yale College ; Dr. T. H. Bean
and Mr. Richard Rathbun, of the National Museum ; Mr.
Sanderson Smith, of New York ; Professor L. A. Lee, of Bow-
doin College ; Mr. B. F. Koons, Mr. E. A. Andrews, and Mr.
H. L. Bruner, graduates and special zoological students of the
Sheffield Scientific School of New Haven, and Mr. Peter
Parker, of Washington. Most of these gentlemen have been
associated with me, in the same way, in previous years.

The off-shore regions explored this year are included between
N. lat. 39° 40' and 40° 22' ; and between W. long. 69° 15'
and 71° 32'. They occupy a region about 42 miles wide, north
and south; and about 95 miles long, east and west, or about
105 miles along the 100-fathom line.

Series of dredgings have also been made this season, off Cape
Cod ; in Vineyard Sound ; in Buzzard's Bay ; and off Martha's
Vineyard, between the deep-water and shallow-water localities
of former years. Other dredgings will be made later, this
season.

It is probable that the remarkable richness of the fauna in
this region, both in the number of species and in the surprising
abundance of the individuals of many of them, is due very
largely to the unusual uniformity of the temperature enjoyed, at
all seasons of the year, at all those depths that are below the
immediate effects of the atmospheric changes. The region
under discussion is subject to the combined effects of the Gulf
Stream on one side and the cold northern current on the other,
together with the gradual decrease in temperature in proportion
to the depth. It is, therefore, probable that at any given depth,
below 50 fathoms, the temperature is nearly the same at all
seasons of the year. Moreover, there is, in this region, an active
circulation of the water, at all times, due to the combined cur-
rents and tides. The successive zones of depth represent suc-
cessively cooler climates more perfectly here than near the coast.
The vast quantities of free-swimming animals, continually
brought northward by the Gulf Stream, and filling the water,
both at the surface and bottom, furnish an inexhaustible supply
of food for many of the animals inhabiting the bottom, and
probably, directly or indirectly, to nearly all of them. A very
large species of Salpa, often five or six inches long, occurs both
at the surface and close to the bottom, in vast quantities. Some-
times several bushels come up in a single haul of the trawl. I
have taken this same Salpa, in very numerous instances, from
the stomachs of starfishes of many kinds, from Actiniae of

294 A. S. Verrill — Marine Fauna occupying the outer banks

Table of Outer Stations, occupied in 1981, with Temperatures of bottom and surface
The distances are measured from Gay Head Light, in geographical miles

«— ■

».

WW.

„.,..

Kttta.

BurToe

Off Martha's

Vinoytiril.

911

S. i W. 59J t

gn. mud

fuiy 16

83° F.

818

6.33 "

919

11 05

61*

7.00 "

920

681

8.30 "

931

9.40 "

932

gn. m. sd.

10 67 "

923

78+

12.21 P. H.

934

" 831

160

44 '5

926

334

sd. m.

3.35 "

936

196

6.24 "

936

S. bj K- i E.

lORJm...
1044 " -

170

nuid

Aug. 4

39'5
39-6

10.43 "

931

103 " ..

gn. a. m.

40*5

12.45 p. K

938

100 '■ ..
98 ;1 ..

310
358

43
47

12-6
73

3.44 "
4.25 "

91 » _.

130

6.30 "

941

R9J " --

ml. mud

7.45 "

S. by W. i M

. 81J " .

134

" 9

6.15 A. M.

943

ABM.

83 " ..

163

7.10 "

944

124

8.37 "

945

8. by W. } Tfl

. 84j- " - -

303

gn. m, ml.

12.05 p. x.

946

P n "

241

2.00 "

941

312

ad. in.

4,00 "

949

791 " --

100

4.30 A. si.

950

6.50 "

951

95 " __

67 '6

9.40 "

953

S.±E,

811 "--

388

y. ro. Hd.

1 1.38 "

953

B. 1 FC

911 " „

115

39-6

3.30 p. it.

954

91 " ..

642

sii mud

39-6

4.50 "

994

9.S.W. i W.

1041 " ..

368

unrf

Sept. 8

40-5

4.60 A.M.

995

1041 " --

358

40-6

6.32 "

996

97-6

7.36 ".

991

1031 " --

iSii

y. in.

87-6

9.03 "

1021 " --

302

gr. ra.

10.34 "

999

100 " ..

366

11.48 "

1035

SS.W. i W.

95 » ..

316

1.06 P. M.

lose

931 " -

182

47-6

2.66 "

1031

S.S.K.JE.

105J "--

One Hiinrt.

11 14

481

1.23 A.M.

1029

1091 " «

410

1039

1091 " --

458

13.13 P.M.

1030

" f

1081 " __

331

1.62 "

1031

" 1

1011 "..

255

3.64 "

1032

" i

101 " _.

208

4.00 "

1033

183

ml. (TlMVCl.

4.65 "

1034

105J " —

146

sd. y. mini.

461

6.66 "

\IW

1031 " ..

ISO

6.56 "

1030

102 ,; ._

sand.

611

7.B4 "

off the soutfiern coast of New England. 295

several species, etc. Pteropods also frequently occur in the
stomachs of the starfishes, while Foraminifera furnish a large
part of the food of many of the mud-dwelling species.

The fishes, which are very abundant and 01 many species,
find a wonderfully abundant supply of most excellent food in
the very numerous species of crabs, shrimp and other Crusta-
cea, which occur in such vast quantities, that not unfrequently
many thousands of specimens of several species are taken in a
single haul of the trawl. Cephalopods are also abundant and
are eagerly devoured by the larger fishes, while others prey
largely upon the numerous gastropods and bivalves.

Fishes.

The fishes obtained by us are of great interest. The large
number of species taken will be indicated by the accompanying
list, which has been kindly made out for me by Dr. T. H. Bean,
who has had charge of the fishes this season. A considerable
number of species, not included in this list, are either unde-
scribed or not fully identified. These will soon be published
in a more detailed list.

The new species of fishes taken in 1880, in this region, were
described by Mr. G. Brown Goode, and a list of the 51 species,
obtained by us, was also published by him (Proc. Nat. Mus.,
iii, pp. 337-467, Nov., 1880, and Feb., 1881).

The most important of the fishes, is the Lopholatilus chamce-
leonliceps Goode and Bean, or '"Tile-fish." This is a large and
handsome edible fish, first discovered on these grounds in 1879,
and not yet found elsewhere. It seems to be very abundant
over the whole region explored by us, in 70 to 184 fathoms.
On one occasion a "long-line" or "trawl-line" was put down
at station 949, in 100 fathoms, and 73 of these fishes were taken,
weighing 541 pounds. These varied in weight from 2J to 31
pounds. It is brownish gray, more or less covered with large
bright yellow spots. The Peristedium miniatum Goode, is a very
curious and handsomely colored fish, often bright red through-
out. The several species of "hake" (Phycis) are common, as
well as the "whiting" (Merlucius bilinearis). Large specimens
of the "goose-fish" or "angler" are often taken in the trawl, in
as much as 250 fathoms.

List of Fishes. By Dr. T. H. Bean.

1 . HalieutcRa senticosa Goode.

Taken at 9 stations; 160 to 335 fathoms; abundant at stations 925 and 951.

2. Lophins piicatorius Linn. (Goose-fish).

Stations 919, 944 and 997 ; 51£ to 335 fathoms; one at each station.

3. Ceniriscus scolopax Linn. (Trumpet-fish.)
One trawled at station 940, in 130 fathoms.

Am. Joan. 801.— Third Series, Vot.. XXII, No, 180.— October, 1881.

296 A. H Verritt — Marine Fauna occupying thejoater banks

4. Hippoglossoides plaiessoides (Fabr.) Gill. (Flounder.)
Taken sparingly at stations 917 and 918; 43 to 45 fathoms.

5. ParaKchthys oblongus (Mitch.) Jordan. (4-spotted Flounder.)
Abundant at station 923, in 96 fathoms; a few taken at 917, 919 and 940. in

43 to 130 fathoms.

6. Monolene sessiHcauda Goode.

A single one caught at 923, in 96 fathoms, sand.

7. Citharichthys arctifrons Goode.

Abundant at numerous stations, in 514 to 130 fathoms.

8. Glyptocephalus cynoglossus (Linn.) Gill. (Pale-flounder.)
Occurred at 13 stations, in 160 to 506 fathoms; abundant at 994.

9. Macrurus Bairdii Goode and Bean. (Baird's Grenadier.)
Obtained at 15 stations, in 160 to 506 fathoms; usually abundant

10. Macrurus carminatus Goode. Grenadier.

Taken at 7 stations, in 182 to 396 fathoms; abundant only at 951 and 952.

11. Phyci8chu88(V?fi\b.)Gm. (Hake.)

Trawled at 5 stations in 43 to 130 fathoms; abundant at 918, 919 and 923.

12. Phycis tenuis (Mitch.) DeKay. (Hake.)

Secured at 12 stations, in 43 to 506 fathoms ; abundant only at 942.

13. Phycis Chesteri Goode and Bean. (Chester's Hake.)
Caught at 15 stations, in 160 to 506 fathoms; generally abundant

14. Physiculu8 Dnlwigkii Kaup. ?

A single young individual was taken at station 952, in 396 fathoms.

15. Physiculus, sp.

Three young examples were obtained at station 941, in 76 fathoms.

1 6. Enchelyopus cimbrius (Linn.) Jordan. (Rock ling.)

Taken in small numbers at 918, 946, 951 and 998; 45 to 302 fathoms.

17. Mer Indus bilinearis (Mitch.) Gill. (Whiting.)

Found at 13 stations, in 100 to 312 fathoms; usually scarce at these depths.

18. Ophidium, sp. undetermined.

14 individuals were trawled at station 941, in 76 fathoms.

19. Ly codes Vahlii Reinhardt.

A singlo individual at each of two stations, 952 and 998, 302 to 396 fathoms.

20. Lycodes Verrillii Goode and Bean.

Taken at 11 stations, in 216 to 368 fathoms; never abundant.

21. Zowrces anguillaris (Peck) Storer. (Eel-pout.)
One obtained at station 918, in 45 fathoms.

22. t Liparis vulgaris Fleming.

Found at station 918, in 45 fathoms, in the gill-cavity of Pectm tenuicostatus.

23. Careproctus Reinhardtii Krdyer.

Taken in small numbers at 5 stations, in 202 to 310 fathoms.

24. Peristedium miniatum Goode.

Rare at stations 922, 940 and 950; 69 to 130 fathoms.

25. Amitra Hparina Goode.

Found at 5 stations, in 310 to 506 fathoms ; not common.

26. Cottunculus microps Collett.

Obtained at 7 stations, in 224 to 396 fathoms ; not common.

27. Cottunculus torvus Goode, MSS.

A single specimen was taken at station 994, in 368 fathoms.

28. Cottus octodecwispinosus Mitchill. (Sculpin.)
One individual was trawled at 917, in 43 fathoms.

29. Sebastes marinus (Linn.) Liitken. (Rose Fish.)

The only one seen was obtained in 241 fathoms, at station 946.

30. Setarches parmatus Goode.

Found at stations 939, 940, 950, in 69 to 258 fathoms; abundant at 940 only.

off the southern coast ofNeto England. 297

31. Lopholatilus chamceleonticeps Goode and Bean. (Tile Fish.)

8 individuals were caught on a trawl-line, near station 942, in 134 fathoms ;
and 73 at station 949, in 100 fathoms.

32. Hbplostethus mediterraneus Cuv.. and Val.

A young example at station 998; one at 1025 and two at 1026; 182 to 302
fathoms.

33. Scopdus, species undetermined.
Abundant at several stations, in 182 to 724 fathoms.

34. Scopelus, species undetermined.

Found sparingly at several stations, in 182 to 506 fathoms.

35. Stomias ferox Reinhardt.

Single individuals were caught at 936, 953 and 995 ; 358 to 724 fathoms.

36. Conger vulgaris Cuv. (Conger Eel.)

One specimen was obtained at 919, and one at 941 ; 51^ to 76 fathoms.

37. Nemichthys scolopaceus Richardson. (Snipe Eel.)

7 individuals were taken at 5 stations, in 216 to 506 fathoms.

38. Synaphobranchvs pinnatus (Gronow) Giinther. (Long-nosed Eel.)
Found at 10 stations, in 219 to 506 fathoms; common.

39. Simenchdys parasiticus Gill. (Pug-nosed Eel.)

A few specimens were obtained at station 937, in 506 fathoms.

40. Raia eglanteria Lac. (Skate.)

Taken sparingly at 924 aud 940, in 130 to 160 fathoms.

41. Raia Icevis Mitchill. (Barn-door Skate.)

Found at several stations, in 43 to 202 fathoms ; abundant at 942 and 949.

42. Raia radiata Donovan. (Skate.)

Found in small numbers at stations 924, 946 and 951 ; 160 to 241 fathoms.

43. Gentroscyllium Fabricii (Reinh.) Mull, and Henle. (Black Dog-fish.)
Taken at stations 952 and 994, in 368 to 396 fathoms ; rare.

44. Peiramyzon marinus Linn. (Lamprey.)

A single specimen was taken in 241 fathoms, at station 946.

45. Myxine glutinosa Linne. (Hag Fish.)

Trawled at 4 stations, in 160 to 258 fathoms ; usually rare, but abundant at 951.

MOLLUSCA.

Most of the mollusca recorded in my papers of last year
were again obtained this season, and often in larger numbers.
A complete list will be published in a future paper. At the
present time I shall refer only to some of the more important
ones, and to some of those that are additions to the fauna.

Of the Cephalopods, the following species were taken :

Oonatus Fabricii Steenstrup.*

Station 953; 715 fathoms; one large and perfect male speci-
men. Station 1031; 255 fathoms; one young specimen.

The former is the form recently figured by Steenstrup, under
the above name, and considered by him the adult of Oonatus
amoenus.

* A direct comparison of this individual with the mutilated specimen described,
by me, last year, as Cheloteuthis rapax, shows that they are probably identical.
The latter was separated, as a genus, from Gonatus, as understood by Steenstrup
(= Lesioteuthis Yerrill) mainly because the ventral arras appeared to have had two
interior rows of hooks, like those on the other arms, while in Oonatus they are

298 A. E. VerriU — Marine Fauna occupying the outer banks

Ommastrephes illecebrosus VerriU.

Stations 918, 919, 923-925, 939, 940, 949, 1025, 1033; 45-258
fathoms.

Taonitfs pavo (Les.) Steenstrup.

Station 952 ; 388 fathoms. Two specimens. This rare
species has not been recorded from our coast, since it was de-
scribed by Lesueur, in 1821.

Rossia sublevis VerriU.

Stations 924, 925, 939, 945-947, 951, 952, 997, 1025, 1026,
1028, 1029, 1032, 1033; 106-388 fathoms. Some of the speci-
mens, recently obtained, agree more nearly with R glaucopis
Lov., as figured by G. O. Sars, than any seen before. It may
prove to be identical.

Heteroteuthis tenera VerriU.

Stations 918, 919, 920, 921, 922, 940, 944, 949, 950, 1026,
1027 ; 45-182 fathoms. Eggs of this species were taken at
stations 922, 910, 949, and in several localities in 1880. They
are nearly round, ivory-white or pearly, attached to shells, etc.,
by one side, in groups, or scattered. On the upper side there
is a small conical eminence.

Sepiola leucoptera VerriU.
Stations 947, 952, 998, 999, 1026 (8 juv.) ; 182-388 fathoms.

Octopus Bairdii VerriU.

Stations 925, 939, 945-947, 951, 952, 994, 997, 998, 1025,
1026, 1028, 1033, 1035; 103-388 fathoms.

composed of suckers, like the outer rows; but the homy parts had been de-
stroyed, in my specimen, and the hook-shaped form of the fleshy part of the
suckers was probably due to post-mortem changes. By careful treatment with
reagents T have been able to restore some of the distal ones more completely, so
as to show a distinctly sucker-like form.

It would, however, be difficult, without farther evidence, to believe that Gonattts
armenus, as figured by G. 0. Sars, is the young of this species, for he neither mentions
nor figures the remarkable series of lateral connective suckers and tubercles on the
tentacular clubs, though he gives detailed figures of the club and its other hooks
and suckers. That so careful an observer as Sars should have overlooked such a
structure seems almost incredible. The two small specimens that I have hitherto
seen from America, agreed well with Sars' figures, but both were considerably
injured from having been in fish -stomachs. A small specimen (mantle 30mm long)
recently taken by us, at station 1031, is, however, well preserved, and while
agreeing with G. amanus in all other respects, it has the peculiar lateral connec-
tive suckers and tubercles of the club, seen in G. Fabricii, adult. These organs
are, however, very minute in this specimen, but sufficiently evident to convince
me that Steenstrup is correct in considering G. amamus the young of G. Fabricii.

Since Steenstrup has shown that the type of my genus Lestoteuthis is the same
genus as Gonatua (adult), and therefore that L. robustus (Dall), doubtfully referred
to it by me. is a distinct genus, I propose to make the latter the type of a new
genus: Moroteuihis. Its most prominent distinctive character will be the remark-
able solid cartilaginous cone, superadded to the end of the peu, and corresponding
in form and position with the solid cone of Belemnites.

off the southern coast of New England. 299

AUopo8us mollis Verrill.

Stations 937, 938, 952, 953, 994 ; 310-715 fathoms. Two
very large females were taken: one at station 937, in 506
fathoms; the other at 994, in. 368 fathoms. The former
weighed over 20 pounds. Length from end of body to tip of
1st pair of arms, 31 inches ; of 2d pair, 32 ; of 3d pair, 28; of
4th pair, 28 ; length of mantle beneath, 7 ; beak to end of 4th
pair of arms, 22; breadth of body, 8*5; breadth of head, 11 ;
diameter of eye, 2*5; of largest suckers, *38.

The only additional Pteropod taken this year is Triptera
columnella (Rang), from station 947. Among the Gastropods
there are a considerable number of species not obtained last
year. Perhaps the most remarkable discovery, in this group,
is a fine typical species of Dolium (D. Bairdii) taken alive, in
202 fathoms. This genus is almost exclusively tropical in its
distribution. On our coast, D. galea extends northward to
North Carolina. This southern form, with a large Marginella,
taken both this year (station 949) and last, an Avicula, and
various other genera, more commonly found in southern waters,
are curiously associated, in this region, with genera and species
which have hitherto been regarded as exclusively northern or
even arctic, many of them having been first discovered in the
waters of Greenland, Spitzbergen, northern Norway, Jan
Mayen Land, etc.

Among the northern species which had not been found pre-
viously south of Cape Cod, the following were dredged: Tro-
phon clathratus, 972, 976 ; Acirsa costulata (=borealis), 965 ;
Amauropsis Islandica {=helicoides) ; Margarita cinerea, 981 ;
Machceroplax bella, 1032 ; Cytichna Gouldii, 973 ; Odostomia
(Menestho) striatula, 980.

Dolium Bairdii Verrill and Smith, sp. nov.

A moderately large species, having nearly the form of D.perdix
and D. zonatum. Male. Shell broad ovate, with seven broadly
rounded whorls ; spire elevated, apex acute ; nuclear whorls
about three, smooth ; suture impressed, but not deep, nor chan-
nelled, the last whorl is somewhat flattened (perhaps abnormally)
below the suture, for some distance, corresponding to an inward
flexure of the outer lip. Aperture elongated, irregularly
ovate ; outer lip regularly rounded, except for a short distance
posteriorly, where it is slightly incurved, its edge is excurved,
acute externally, distinctly but not prominently crenulated
within, except posteriorly, where a posterior canal is slightly
indicated ; columella straight ; canal short and broad. The
sculpture is peculiar: it consists of numerous (about 40 on the
last whorl) rather prominent, squarish, clearly defined revolv-
ing ribs, less than lmm broad, separated by interspaces of about

800 A. E. Verrill — Marine Fauna occupying the outer banks

the same breadth, in which there is usually one small narrow
rib, alternating with the larger ones; sometimes there are two
or more small ones. The whole surface, both of ribs and inter-
spaces, is covered with fine and regular transverse, raised
lines. The surface is covered with a very thin pale olive-
yellow epidermis, easily deciduous when dry. Color white, ex-
ocpt that the larger ribs are alternately light brown and white,
and the apex, consisting of about three smooth nuclear whorls,
is dark brown. Length OS11"11; breadth SO™; length of aper-
ture OS™.

The animal is well preserved. Proboscis blackish, exserted
about 20mm, thick (8**) and clavate at the end, which is sur-
rounded by a sort of collar, with a finely wrinkled or crenulated,
white edge. Head large, with a prominent rounded lobe in
front Tentacles large, elongated (lO""*), stout, tapering, obtuse.
Kyes small, black, on distinct, but slightly raised tubercles at
the outer base of the tentacles. Head, tentacles and siphon-
tube dull brown. Penis very large (SO""* long, 12mm broad),
twisted and thickened at base, flattened distally, terminating in
a slightly prominent obtuse lobe at the tip; a well-marked
groove runs along the posterior edge to the tip.

OlV Martha's Vineyard, station 945 ; 202 fathoms. Station
1086 ; 94 fathoms ; one young specimen and large fragments.

Heurototna (Beta) Umacina Dall. (J)aphnella ?)

Bulletin Mus. Comp. Zool.. ix, p. 55, 1881.

Four living specimens of this elegant shell were taken at
station 994 : 368 fathoms. Gulf of Mexico, 447-805 fathoms
(Pall). This is not a true Beta, for it has no operculum ; eyes
minute.

Vapidus hungaricus (Linnt*).

Two living specimens were obtained, which appear to belong
to this species They are more delicate and have somewhat
finer and more regular radiating ribs than the ordinary Euro-
pean form. It has not been recorded before from our coast

Stations 922, 1029 : 69 and 458 fathoms.

J'lona uobilis Alder and Han.

British Xud. Moll., J^olidi^, Fam. 3. pi. 38A.

A large and handsome Fiona, apparently this species, was
found in two instances, in large numbers, on pieces of floating
timber, among Anatifers, at stations 935 and 995. Thev were
kept in confinement several days and laid numerous clusters of
eggs. These are in the form of a broad ribbon, spirally coiled
in about one and a half turns, so to form a bell-shaped or cup-
shaped form, and attached by a slender pedicel, so as to hang
from the under sides of objects. Alder and Hancock recorded
its occurrence, in a single instance, at Falmouth, England.

off the southern coast of New England. 301

Issa ramosa Verrill arid Emerton, sp. nov.

Body elevated, convex above, elongated, oblong, sides nearly
parallel along the middle ; foot well-developed, as broad as the
body. Dorsal tentacles thick, clavate, obtuse, with numerous
lamellae ; sheath scarcely raised. Back and sides with numer-
ous small, simple papillae. Along the lateral margins of the
back there is a carina, with a row of large, much branched
papillae, alternating with much smaller ones ; of the large ones
there are about six on each side, the most anterior are below
the dorsal tentacles ; two on each side are posterior to the gills,
the last ones largest ; a row of similar but smaller processes ex-
tends below the tentacles and around the front margin.

Gills five, arborescently branched. Color, pale yellow. The
dorsal tentacles darker.

The radula is quite different from that of L lacera and Triopa
claviger. The median area is wide, with two rows of thin,
transversely oblong plates ; there are three rows of large, nearly
equal teeth on each side, with the tips strongly incurved, ob-
tuse ; the innermost tooth has a small lobe on the middle of the
inner edge : these are followed by about seventeen or eighteen
smaller, oblong plates, with slightly emarginate anterior ends;
these gradually decrease in size toward the margins of the
radula.

Stations 940, 949 ; 130 and 100 fathoms.

In form, this resembles L lacera, but is easily distinguished
by the branched appendages along the sides.

Of the Lamellibranchiata, some very interesting new forms
occurred. The most important of these are species of Phola-
domya, Mytilimeria, and Diplodonta, — three genera not before
found on this coast. The Pholadomya is more related to cer-
tain fossil forms than to any of the few described living species.
The genus Mytilimeria has hitherto had very few living repre-
sentatives, and none of them resemble our very singular
species.

Among the northern forms, not previously found south of
Cape Cod, are the following: Mya truncata; Spisula ovalis
(975, 976, 981) ; Leda tenuisulcata (973) ; Nucula tenuis.

Pholadomya arata Verrill and Smith, sp. nov.

Shell triangular, short, wedge-shaped, posterior end angular,
somewhat produced, obtuse; anterior end very short and ab-
ruptly truncated, clearly defined by a carina extending from the
beak to the outer margin ; anterior to the carina there is a broad
concave furrow, which bounds the slightly convex central area
of the front end ; the greater part of the sides of the shell is cov-
ered with deep, rather wide, concave furrows, separated by ele-
vated, sharp-edged ribs ; the furrows vary in width and decrease

302 A. E. Verrill — Marine Fauna off New England coast,

posteriorly ; a small portion, near the tip of the posterior end is
covered only by slight ribs. The surface between the ribs is
finely granulated. When the thin superficial layer is removed
the surface is pearly. The umbos are prominent, strongly in-
curved, nearly or quite in contact. The hinge in the right valve
consists of a small, slightly prominent lamella, running back as a
low ridge, and separated from the margin of the shell anteriorly,
and from the cartilage-lamina posteriorly, by a narrow groove;
the cartilage-pit is long, running forward under the beak as a
a narrow furrow; it is bounded internally by a. prominent
lamella. Length, 36mm ; height, 29 mm ; breadth, 26liun.

Stations 940, 949, 950 : 69 to 130 fathoms.

Three specimens, all dead, but one is very fresh.

Mytilimeriaflexuo8a Verrill and Smith, sp. no v.

Shell obliquely cordate, short, higher than long, very swollen,
the anterior end rather shorter than the posterior; umbos very
prominent, beaks much incurved, pointed and turned forward,
with a small, deep concavity just under and in front of them.
The outline and surface of the shell is very flex uo us, owing to
the broad deep grooves and elevated ribs which divide the sur-
face into several areas. The most prominent rib is very high
and rounded, and runs from the beak to the extreme ventral
margin, inclining somewhat forward; in front of this the ante-
rior area is flattened with a wide shallow concave groove or
undulation in the middle, and others less marked ; the front
edge is broadly rounded, slightly undulated below. The mid-
dle area is very elevated, and forms more than a third of the
shell ; it is flattened or slightly concave in the middle, and
undulated by several faint broad ribs ; it recedes posteriorly,
and a broad concave furrow separates it from the small poste-
rior area, which is without ribs, and has a prominent rounded
edge. The surface is finely granulated, lines of growth evident
The interior is pearly, angulated by a deep groove, correspond-
ing to the largest external rib. The dorsal hinge-line is nearly
straight posteriorly, and strongly incurved anteriorly, in the
right valve it projects inward, but not in the left ; in the right
valve there is a small rounded tubercle, a little back of the
beak ; from below this a short rib-like process runs back below
the deep, partially internal cartilage-pit, which extends forward
and upward under the beak as a narrow furrow. Anterior
muscular scar deep; posterior one larger ovate, less distinct;
sinus small. Length, 25mm ; height, 26mm ; breadth from side
to side, 22mm.

Station 947 ; 312 fathoms. One pair of fresh valves, dead.

This and the preceding were both taken by means of the
"rake-dredge."

L. Boss— Tail of Comet b, 1881. 303

Diplodontaturgida Verrill and Smith, sp. nov.

Shell large for the genus, round-ovate, a little longer than
high, very swollen ; the two ends nearly equally rounded, the
anterior a little narrower; ventral edge broadly and regularly
rounded ; beaks nearly central, somewhat forward of the mid-
dle, strongly curved inward and forward, acute. Surface with-
out sculpture, smooth except for the evident lines of growth.
In the right valve there are, opposite the beak, two nearly equal,
stout, sharp teeth, separated by a space of about the same
width; bacK of these, and partly joined at base to the posterior
one, there is a much larger, broad, stout, obtuse tooth, with a
groove on its dorsal side ; external cartilage-groove and its
lamella are long and narrow, curved. Length, 29mm; height
(umbos to ventral edge), 25mm; breadth, 23mm.

Station 950; 69 fathoms. One right valve.

Art. XLIL — Note on the Tail of Comet b% 1881 ; by Lewis

Boss. With Plates V and VI.

The changes which took place in the aspect of the tail of the
great comet of 1881, during the last days of June, seemed to
me of peculiar and unusual interest Appearances so novel
and unexpected moved me to prepare some rude sketches of
the tail, with brief notes as to its position in the sky. From
several causes my opportunities for making such studies
proved to be very few, and lack of experience contributed to
diminish the completeness and accuracy of the results actually
obtained. It is to be regretted that the number of those who
give serious and systematic attention to this branch of obser-
vation is quite small in view of the small number of opportu-
nities; while, on the other hand, the observations which can
be made are uncertain in character, and the results vary much
with individual judgment. It is therefore important that
drawings and descriptions should be gathered from as many
sources as possible.

The engravings (Plate V), accompanying this paper were
reduced from drawings compiled from the original sketches
and notes.

These were made in the open air at the times of observation
indicated. In all cases the chief object of interest was what
may be conveniently termed the right-line tail, which was far
more conspicuous than the other branch on June 26, scarcely
perceptible on June 28, and entirely wanting on July 1. It is
to be regretted that on these dates charts were not used in the
preparation of the original sketches, except for reference. The
final drawings were laid down on copies of Schwinck's polar

304 L. Boss— Tail of Comet b, 1881.

chart (1850) from the original sketches and notes. On July
22 the outlines of the tail were drawn with care on the Dutch-
musterung polar chart (Argelander, 1855), and from thence
accurately transferred to the finished sketch. The distortion
of figure, owing to the projection used, is not important in any
case, and for the purposes of this communication it is inappre-
ciable. The engraver has been very successful in preserving
the accuracy of the original drawings, and in imparting to
them the desired effects. The following is the substance of the
notes recorded :

June 26, 10h. — Air wonderfully transparent. The tail of the
great comet consists of two branches. The principal branch
appears to be perfectly straight, and passes about two degrees to
the apparent east of Polaris and eight or ten degrees beyond it
For the last ten or fifteen degrees this branch is exceedingly
faint. The other is curved quite strongly to the apparent west,
and after its separation from the principal ray requires most care-
ful scrutiny for its detection. It seems to extend to a point six
or seven degrees, astronomically southeast from Polaris.

June 26, 13h 30m. Sketch. — The tail presents to the naked eye
much the same appearance as it did earlier in the evening, except
that neither branch can be traced so far as then seen. The
straight branch appears to pass quite centrally over 2 Urs®
Minoris, and to extend about two degrees beyond B. A. C. 7851.
Its breadth seems to be nearly uniform and a little more than one
degree. With the aid of a straight edge no curvature could be
safely assigned. There is a rather sudden falling off in brightness
at a point four or five degrees from 2 Ursse Minoris toward the
nucleus. The edges of this ray are ill-defined and the central
parts brightest. The ray which curves toward greater right
ascension is not satisfactorily seen. Its effect is to broaden and
intensify the principal ray for a distance from the nucleus equal
to about four-tenths the whole distance to Polaris. At this point
the total breadth of the tail is estimated to be about four degrees.
Here a separation is faintly indicated, but the continuation of the
curved ray is observed with extreme difficulty. The direction
and extent of this branch is indicated on the sketch.

June 28, 13b. Sketch. — Foggy haze low down in the north.
Sky otherwise satisfactory. The nearly straight ray described
on June 26 has dwindled to a faint and narrow streak, which
might have been overlooked, had not a bright one been expected
in its place. It extends to a point near 2 Ursse Minoris as indi-
cated in the sketch. Its breadth is not over one-third of a degree.
The curved branch is brightest in its central parts, and is very
conspicuous for the first ten or fifteen degrees of its length, ft
seems to terminate about three degrees short of B. A. C. 4349;
though at times a much greater extent is suspected. Fifth mag-
nitude star (B. A. C. 2326) is 15' inside the following edge of the
tail. The axis of this branch passes to the apparent east of

L. Boss— Tail of Comet 6, 1881. 305

B. A. C. 4349, and at a distance from it equal to about one-fifth
the distance between that star and Polaris. The last direction of
the axis is toward ft Ursse Minoris. The distance of Polaris from
the preceding edge of the tail is nearly equal to the distance
between Polaris and 2 Ursae Minoris. The breadth at three-
fourths the distance from the nucleus is about three degrees.

July 1, 12h 15m. Sketch. — State of sky not remarkably fine.
The tail is much shorter than heretofore, and its appearance
entirely changed. There is no trace of the straight ray seen on
June 26 and 28. The preceding edge of the tail appears nearly
straight. It is brighter and extends to a greater distance from
the nucleus than the following edge. The latter is strongly
curved near the end. The breadth is about three degrees at the
widest part.

July 13, 10h 15m. — Tail single, faint, and diffuse. Estimated
length seven degrees. Breadth near the end, about 40'. The
direction of the axis prolonged passes to the east of € Ursae
Minoris, at a distance about one fifth that between € and 6 Ursae •
Minoris.

July 22, 14h. Sketch. — Four-inch Clark Comet seeker. Power
twelve. Field 2° 30'. Sky fine. * Two branches seen. The first
is nearly straight and brighter than the other. Estimated width
10'. This branch is certainly recognized as far as A. R. 14h 20m.
Sometimes I imagine that it extends as far as A. R. 15h 40,n. [As
indicated by the dotted line in diagram.] The light seems to be
composed of a great number of parallel bright streaks. This
appearance of striation is very decided in the region within two
degrees of the nucleus. The southern branch is curved and much
shorter and fainter than the straight ray. The location of the
last degree of length represented in the sketch is very difficult.
The breadth here is estimated to be 30' or 40'. The bounding
lines are carefully laid in on the I>urchmusterung chart, and their
position relatively to stars frequently compared with the sky
during the progress of the sketch. Sky suddenly clouded at
14h 30m.

During the remainder of July the appearance of the tail did
not essentially change. I was absent from the observatory for
a short time in the early part of August, and did not again
obtain a telescopic view of the tail until August 17. It was
then apparently single. The estimated length was 3°. There
are slight inconsistencies in the notes of June 28, which have
been adjusted according to the supposed weights of the various
estimations.

For the points most carefully determined, and with such
approximation as appears to be warranted by the precision of
the observations, we have for positions of points in the tails on
the respective dates :

306

L. Boss— Tail of Comet 6, 1881.

Table I.

Juno 26, 13h 30m
June 28, I3h 00
July 1, 12h 15™
July 22, 14h 00

Nucleus.

Axis, right-line tail.

Curved tall.

87°2

57°-9

316°

83°-0

99°

80°-5

* m a* m

• « m —

13*2

85'6

90' 1

63-9

20*

85-9

155

86-0

• V V M

« •• — —

m — » »

100

83-0

958

707

* * « M

111-2

87-0

• v m m

• — — *

w m m ^

115-3

80-0

1776

81-9

215-4

828

2050

822

Point in

curved tail

observed.

Axis.

Axis.
Prec. edge.
Foil. edge.

Axis. "

It would have been better, no doubt, to have made no
special effort to determine the position of the extreme visible
limit of the tail, but to have given greater attention to the
position of the axis and the breadth of the visible portions at
points where the tail could be easily seen. But even with the
present imperfect data, we shall be able to derive some idea of
the real position of the tails in space, and of their correspond-
ence in type with others which have been observed.

Convenient formulae have, been devised by Bessel (Astr.
Nachr., vol. xiii, p. 193), by the use of which we may determine
the angular deviation of a point in the tail from the radius
vector prolonged. It will be necessary to assume that the axis
of the tail lies in the plane of the orbit of the nucleus. This
assumption is well supported both by theory and experience,
and is, no doubt, substantially correct. Such small deviations
as might result when emissions of matter from the head are
unsymmetrical with reference to the orbit plane, or when the
initial velocity of particles thrown off' from the nucleus is
greater toward one pole of the orbit than toward the other, may
probably be neglected as comparatively insignificant. Let:

r=Radius vector of the nucleus at the time of observation.

p= Geocentric distance of nucleus.

A=Length of tail, or distance of point observed from the nucleus.

s= Angular length of tail.

p°= Position angle at the nucleus of r prolonged.

p= Corresponding angle for the observed point in the tail.

8= The cometocentric distance of the earth from the north pole

of the comet's orbit.
T= Cometocentric angle between the earth and the observed

point in the tail.
(p'=The cometocentric angle between the observed point and the

radius vector prolonged, — positive, when this point is on

that side of the radius vector from which the comet has

been moving.

From the elements of Dr. Oppenheim (Astr. N., 2384), we
find for the coordinates of the north pole of the orbit of cornet
bj referred to the equator,

A=192° 09'.

D= +23

° 4(>'.

L. Boss— Tail of Comet b, 1881.

307

We then derive the following table of results :

Table II.

r
P

June 26.

•763

•340

•210

37°'0

3456

3612

102-9

40-2

12-9

ha
ffc*

JSata

•187
31cl

351-8

39'i
14-0

VI CO .

»« 00

June 28.

•179
22°-9

24-9
29 8

•775

•374

161

25°-0

348 6

350 8

106-1

540

5 6

OS .

3 «

July 1.

.5,®

0) o8

•189
24°'7

~~8~7

30-0
32-1

•153
19°-2

3-7

34~4
27-0

•795

•428

130

16°4

3531

2-8

110-3

518

21'1

t«f2
a*

O 91

O of)

110
10°'4

18-6

329
41-5

313

July 22.

■4

2l«

1-018

•853

0-82

5°0

57-7

61-5

1216

109-8

oo>S

«1

067
3°-9

71*8

94-1
249

An inspection of the foregoing table shows that the char-
acteristics of the two branches of the tail, as defined bv the val-
ues of <p\ present a similarity quite as striking as could have
been predicted in view of the considerable probable errors to
which such determinations are liable. On the first. three dates
the cometocentric elevation of the earth above the plane of the
comet's orbit was, respectively, 13°, 16°, and 20° only ; so
that small errors in the observed position angle are consider-
ably multiplied when converted into the corresponding values
of.jp'. It must also be remembered that many of the points
observed are several degrees farther from the nucleus than the
superior limit of visibility assigned by most observers for the
extent of the tail on the respective dates.

So far as I am aware most of the observers who have
already reported on the appearance of the tail failed to notice
the division into branches at all. On the other hand, it can-
not be supposed that this interesting aspect entirely escaped
detection under proper conditions of sky and terrestrial sur-
roundings.

If we examine similar computations which have been made
6n the tails of other great comets we see that the two branches
resemble the two types most frequently observed. The right-
line tail corresponds to the principal appendages of the great
comets of 1811, 1835 (Halley's), 1843, 1861, 1862, and others.
The general direction also conforms to that of the secondary
tail of the great comets of 1858, 1874 and others ; but in the
present case the light of this tail is relatively far more conspic-
uous. The branch of greater curvature finds its representa-
tive in the great majority of comets which have been observed.

308 L. Boss— Tail of Comet 6, 1881.

The tail of the comet of 1807 presents most striking resem-
blance to this under discussion. On October 22, 1807, the
comet of that year had, generally speaking, the same position
in space as the present comet had on July 22. On that occa-
sion (Astr. Nachr., vol. xiii, p. 228), Bessel found two tails.
The first he considered to be nearly straight and in length
about 4*5°. The other was strongly curved, broader than the
first, and in length about 3°. Dr. Bredichin (Mosc. Ann., vol. v,
pt 2, p. 56), has computed the value of <p' for the end of each
tail. This enables us. to compare the two descriptions in a very
satisfactory manner. We have —

Comet of 1807. Comet of 1881.

A p' s A p* 8

For the right-line tail, - - *139 1°-9 4°5 -082 6°2 5°0

For the curved tail, - - - -105 24*2 3'0 *057 24*9 3*9

Allowing for the difference in values of A and r, the agree-
ment is quite within the probable errors of observation. It is
thus seen that there is great similarity in the physical appear-
ance of the two comets, as well as between the elements 01 their '
respective orbits. Since, in general, we have the greatest pos-
sible variety in the appearance of the tails of the comets, and
especially in the combination of tails of different types, we may
confidently say, that the very remarkable similarity above
shown furnishes another important fact, in addition to those
which already tend to indicate a common origin for the comets
of 1807 and 1881.

Sir Isaac Newton and others after him have shown that the
tail might be produced by a repulsive force emanating from the
sun, and acting on detached particles, which are continually
thrown out from the nucleus of all great comets. Bessel has
investigated formulae (Astr. Nachr., vol. xiii) which enabled
him to compute the repulsive force necessary to produce a tail
of the form actually observed in the case of Halley's comet
The repulsive force in these formulae is, of course, an implicit
function. Bessel's formulae are shown (Mosc. Ann., vol. v, pt
2) to give results which are but roughly approximate for large
distances from the nucleus. Professor Norton, Dr. Bredichin
and others have published formulae which are more rigorously
exact. In all these investigations it is supposed that a particle
projected from the nucleus is repelled by a force (1— /*) the re-
verse of the Newtonian. The effective force acting on the par-
ticle will be /*, and when combined with the tangential velocity
of the nucleus will cause it to describe a hyperbolic orbit This
hyperbola will be convex or concave to the sun, according as
(1—//) is greater or less than unity. In the volumes of the Mos-
cow Annals, Dr. Bredichin presents a variety of reasearches
concerning the consequences to be deduced from this assump-
tion of repelling forces.

L. Boss— Tail of Comet 6, 1881. 309

He refers the tails of comets to three general types, distin-
guished by the value of (1— //) employed in their theoretical rep-
resentation. The value of (1— /*) (expressed in the Newtonian
unit) for Type I is 11-0 to 12*0 ; for Type II, about 1-8 ; for Type
III, 0*3, or less. The value of (1— /*) for Type II, however, is
found to vary considerably in different cases without losing
its distinctive character. It is possible to introduce the effect
due to the initial velocity of projection from the nucleus, and
this, of course, modifies the value of (1— ft) which would other-
wise be assumed. This effect will evidently be proportionally
least in tails of Type I, and will increase in importance as the
value of (1—/*) is diminished. If we suppose particles to be
projected from the nucleus equally in all directions with equal
velocities, the effect will be mainly shown in the breadth of the
tail. Thus we invariably find tails of Type I to be narrow in
comparison with those of Type II, — a fact which finds satisfac-
tory explanation in the relatively small effect, which would be
.produced by the action of initial velocity, when the repelling
iorce is relatively very great. But since cometary emissions
appear to take place mostly on the side of the nucleus nearest
the sun, the assumption of the value zero for initial velocity
will always render the value of (1— /jl) computed from observa-
tion, too small.

It will be interesting to examine our observations of the tail
of comet b 1881, with a view to determining to what extent
they conform to. the normal types. In a preliminary discussion
like this, which is founded on few observations of small weight,
it will not be worth while to include the effect of initial velocity
of "emission. When a great number of observations of the tail
and coma have been collected, it may be possible to arrive at
some satisfactory result in this direction. I have accordingly
computed the hyperbolic orbits of particles emitted from the
nucleus at various times (previous to the observations on the
tail), with values of (1— p) equal to *6, 1*0, 14 and 11*0. The
values of the radius vector and true parabolic anomaly of the
nucleus have been computed from the elements of Dr. Oppen-
heira, previously cited.

Let:

M = Date when a given particle is observed in the tail.

M'= Time of emission of that particle from the nucleus.

M"= Perihelion passage of the -particle.

E = Eccentricity of the hyperbolic orbit.

1= Angle between the radii vectores of the particle and nucleus
at the time M. For the particle referred to the nucleus,
this angle will evidently always be retrograde to the
motion of the nucleus.

6 = Distance of the particle from the nucleus at the time, M.

310 L. Boss— Tail of Cornel b, 1881.

tf z= Length of perpendicular let fall from the particle on r pro-
duced at the time, M.
B, = Distance from the foot of that perpendicular to the nucleus.

q> = Angle whose sine is ~, or the angle between r prolonged and

the line joining the nucleus and particle at the time M.

As an example of the manner in which the theoretical lines
of Plate VI have been constructed, the results of computations
intended to represent the right-liue tail of June 26*805 (Berlin
time) are subjoined. The value of (1— /*) is assumed to be 11*0;
and the hyperbolical orbits are computed for particles emitted
at perihelion, and for two designated dates subsequent to that
time. We have :

June 16*510

June 18-510

June 20-510

June 16*510

June 18-359

June 20-205

logE

0-0792

0*0791

0-0788

4° 15'

2° 29'

1° 13'

•284

•192

•no

•273

•187

•109

•077

•041

•018

15°-7

12° 4

9° -5

From the values of J, £, and 37, the curve marked I in the
figure for June 26 (PL VI) is constructed. From that curve we
derive by a graphic process the values of <p corresponding to
the observed values of J at two points in the tail on that date.
We thus have :

A <f>' 0

June 26*805 I '210 12°-9 13°-2

Type I ( '187 14*0 12*3

The agreement between the values of <p' and (p is even closer
than could have reasonably been expected from the unavoid-
able probable error in the determination of <p\

In the diagrams of Plate VI, the point N represents the posi-
tion of the nucleus at the respective times of observation.
N B/ is the radius vector prolonged. The curves N I are care-
fully constructed in the original diagrams from the computed
positions of two or more partic'es, when (I— //)=H-0. The pre-
vious dates of emission were so chosen that one or more com-
puted points would fall near that which was actually observed.
The curves N II were constructed with (1— fi)=l'4ti and may
represent the tail of Type II.' The intervals between dates
of emission and observation for like values of A are much
greater in this case than in that for tails of Type I. The curves
N II" are constructed with (1— //)=1'0 ; and N III" for July
22, is based on (1— /i)=0"6. The dots enclosed in small circles
indicate the positions of points in the tail actually observed.

L. Boss— Tail of Comet 6, 1881.

311

The computed positions of these are given in table IL The
dotted lines are intended to give a rough idea of the outlines
of the tail as observed and reduced to the plane of the orbit, on
the somewhat doubtful assumption that the thickness of the tail
may be neglected in comparison with its breadth in the plane
of the orbit. Following is a tabular view of the results ob-
tained by computation, with the corresponding values from
observation.

fABLB III.

Date.

Type I. (l-/x) = 11-0.

Type II.

Point

A
210

12-9

13*2

*-¥

+ *3

Point
II'

•179

29-8

31*2

(1-/*)

June 26

+ 1-4

1-4

•187

14-0

12*3

-1'7

June 28

•101

5-6

11-0

+ 5-4

•189

32*1

32*8

+ *7

1-4

•153

27-0

29-7

+ 2-7

1-4

July 1

•120

31-3

26"5

—4-8

1-4

July 22

•082

6*2

5*7

— -5

•057

24-9

12-
16-

— 13*

— 9'

1-4
1-0

21*

— 4*

•6

A value of 04 for (1—/*) would give a fair approximation to the
tail of Type II as observed on July 22. The agreement of the
observed and the computed values of <p for the tail of the first
type is very satisfactory. The deviation of five degrees on
June 28 might easily be attributed to errors of observation on
an object which was so excessively faint; and it is quite prob-
able that the location of the end point was somewhat influenced
by the general direction of the tail nearer the nucleus where it
was brighter. Such an influence would tend to make the ob-
served value of <p too small. The two values of <p* best deter-
mined for Type I are the second and fourth of the table ; and
these both indicate that a smaller value of (1—/*) should have
been employed.

With reference to the comparisons of observed and computed
if in the tail of the second type, we do not expect an accord-
ance so satisfactory. The difficulties of observation were greater
with this branch of the tail, which was broad and faint at its
extremity ; and, furthermore, an error in location of this shorter
branch would have a greater influence upon the value of <p'.
The probable uncertainty in the value of tp' for the first three
dates I estimate at three or four degrees. On July 22 the
location of the shorter branch of the tail was extremely difficult ;
still I cannot think that the probable uncertainty in <p' is greater
than four or five degrees. This would make any value of (1— fi)

Am. Jour. Sci.— Third Series, Vol. XXII, No. 180.— October, 1881.

302 A. JE Verrill — Marine Fauna off New England coast.

posteriorly ; a small portion, near the tip of the posterior end is
covered only by slight ribs. The surface between the ribs is
finely granulated. When the thin superficial layer is removed
the surface is pearly. The umbos are prominent, strongly in-
curved, nearly or quite in contact. The binge in the right valve
consists of a small, slightly prominent lamella, running back as a
low ridge, and separated from the margin of the shell anteriorly,
and from the cartilage-lamina posteriorly, by a narrow groove ;
the cartilage-pit is long, running forward under the beak as a
a narrow furrow ; it is bounded internally by a prominent
lamella. Length, 36mm ; height, 29 ^ ; breadth, 26™.

Stations 940, 949, 950 : 69 to 130 fathoms.

Three specimens, all dead, but one is very fresh.

Mytilimeria flexuosa Verrill and Smith, sp. no v.

Shell obliquely cordate, short, higher than long, very swollen,
the anterior end rather shorter than the posterior; umbos very
prominent, beaks much incurved, pointed and turned forward,
with a small, deep concavity just under and in front of them.
The outline and surface of the shell is very flexuous, owing to
the broad deep grooves and elevated ribs which divide the sur-
face into several areas. The most prominent rib is very high
and rounded, and runs from the beak to the extreme ventral
margin, inclining somewhat forward; in front of this the ante-
rior area is flattened with a wide shallow concave groove or
undulation in the middle, and others less marked ; the front
edge is broadly rounded, slightly undulated below. The mid-
dle area is very elevated, and forms more than a third of the
shell ; it is flattened or slightly concave in the middle, and
undulated by several faint broad ribs ; it recedes posteriorly,
and a broad concave furrow separates it from the small poste-
rior area, which is without ribs, and has a prominent rounded
edge. The surface is finely granulated, lines of growth evident
The interior is pearly, angulated by a deep groove, correspond-
ing to the largest external rib. The dorsal hinge-line is nearly
straight posteriorly, and strongly incurved anteriorly, in the
right valve it projects inward, but not in the left; in the right
valve there is a small rounded tubercle, a little back of the
beak ; from below this a short rib-like process runs back below
the deep, partially internal cartilage-pit, which extends forwarA.
and upward under the beak as a narrow furrow. Anterior"
muscular scar deep ; posterior one larger ovate, less distinct ~
sinus small. Length, 25mm ; height, 26mm ; breadth from sid^
to side, 22™.

Station 947 ; 312 fathoms. One pair of fresh valves, dead.

This and the preceding were both taken by means of th ^
"rake-dredge."

L. Boss— Tail of Comet b, 1881. 303

lodonta turgida Verrill and Smith, sp. nov.
hell large for the genus, round-ovate, a little longer than
i, very swollen ; the two ends nearly equally rounded, the
irior a little narrower; ventral edge broadly and regularly
ided ; beaks nearly central, somewhat forward of the mid-
strongly curved inward and forward, acute. Surface with-
sculpture, smooth except for the evident lines of growth,
he right valve there are, opposite the beak, two nearly equal,
t, sharp teeth, separated by a space of about the same
th; back of these, and partly joined at base to the posterior
there is a much larger, broad, stout, obtuse tooth, with a
>ve on its dorsal side ; external cartilage-groove and its
ella are long and narrow, curved. Length, 29mm; height
bos to ventral edge), 25mm ; breadth, 23mm.
tation 950; 69 fathoms. One right valve.

p. XLIL— Note on tiie Tail of Comet b< 1881 ; by Lewis
Boss. With Plates V and VI.

he changes which took place in the aspect of the tail of the
it comet of 1881, during the last days of June, seemed to
of peculiar and unusual interest Appearances so novel

unexpected moved me to prepare some rude sketches of
tail, with brief notes as to its position in the sky. From
iral causes my opportunities for making such studies
zed to be very few, and lack of experience contributed to
inish the completeness and accuracy of the results actually
lined. It is to be regretted that the number of those who
5 serious and systematic attention to this branch of obser-
on is quite small in view of the small number of opportu-
3s; while, on the other hand, the observations which can
nade are uncertain in character, and the results vary much
i individual judgment It is therefore important that
wings and descriptions should be gathered from as many
rces as possible.

'he engravings (Plate V), accompanying this paper were
uced from drawings compiled from the original sketches

notes.

.^ese were made in the open air at the times of observation
icated. In all cases the chief object of interest was what
y be conveniently termed the right-line tail, which was far
re conspicuous than the other branch on June 26, scarcely
ceptible on June 28, and entirely wanting on July 1. It is
3e regretted that on these dates charts were not used in the
paration of the original sketches, except for reference. The
il drawings were laid down on copies of Schwinck's polar

304 L. Boss— Tail of Comet b, 1881.

chart (1850) from the original sketches and notes. On July
22 the outlines of the tail were drawn with care on the Durch-
musterung polar chart (Argelander, 1855), and from thence
accurately transferred to the finished sketch. The distortion
of figure, owing to the projection used, is not important in any
case, and for the purposes of this communication it is inappre-
ciable. The engraver has been very successful in preserving
the accuracy of the original drawings, and in imparting to
them the desired effects. The following is the substance of the
notes recorded :

June 26, 13h 30m. Sketch. — The tail presents to the naked eye
much the same appearance as it did earlier in the evening, except
that neither branch can be traced so far as then seen. Toe
straight branch appears to pass quite centrally over 2 Ursae
Minoris, and to extend about two degrees beyond B. A. C. 7851.
Its breadth seems to be nearly uniform and a little more than one
degree. With the aid of a straight edge no curvature could be
safely assigned. There is a rather sudden falling off in brightness
at a point four or five degrees from 2 Ursae Minoris toward the
nucleus. The edges of this ray are ill-defined and the central
parts brightest. The ray which curves toward greater right
ascension is not satisfactorily seen. Its effect is to broaden and
intensify the principal ray for a distance from the nucleus equal
to about four-tenths the whole distance to Polaris. At this point
the total breadth of the tail is estimated to be about four degrees.
Here a separation is faintly indicated, but the continuation of the
curved ray is observed with extreme difficulty. The direction
and extent of this branch is indicated on the sketch.

June 28, 13*. Sketch. — Fogsrv haze low down in the north.
Sky otherwise satisfactory. The nearly straight ray described
on June 26 has dwindled to a faint and narrow streak, which
might have been overlooked, had not a bright one been expected
in its place. It extends to a point near 2 Ursa? Minoris as indi-
cated in the sketclu Its breadth is not over one-third of a degree.
The curved branch is brightest in its central parts, and is very
conspicuous for the first ten or fifteen degrees of its length. It
seems to terminate about three degrees short of B. A. C. 4349;
though at times a much greater extent is suspected. Fifth mag-
nitude star (R A. C 282o) is 15' inside the following edge of the
tail. The axis of this branch passes to the apparent east of

L. Boss— Tail of Comet J, 1881. 305

B. A. C. 4349, and at a distance from it equal to about one-fifth
the distance between that star and Polaris. The last direction of
the axis is toward /? Ursse Minoris. The distance of Polaris from
the preceding edge of the tail is nearly equal to the distance
between Polaris and 2 Ursae Minoris. The breadth at three-
fourths the distance from the nucleus is about three degrees.

July 1, 12h 15m. Sketch. — State of sky not remarkably fine.
The tail is much shorter than heretofore, and its appearance
entirely changed. There is no trace of the straight ray seen on
June 20 and 28. The preceding edge of the tail appears nearly
straight. It is brighter and extends to a greater distance from
the nucleus than the following edge. The latter is strongly
curved near the end. The breadth is about three degrees at the
widest part.

July 13, 10h 15ni. — Tail single, faint, and diffuse. Estimated
length seven degrees. Breadth near the end, about 40'. The
direction of the axis prolonged passes to the east of € Ursas
Minoris, at a distance about one fifth that between € and d Ursse
Minoris.

July 22, 14h. Sketch. — Four-inch Clark Comet seeker. Power
twelve. Field 2° 30'. Sky fine. * Two branches seen. The first
is nearly straight and brighter than the other. Estimated width
10'. This branch is certainly recognized as far as A. R. 14h 20m.
Sometimes I imagine that it extends as far as A. R. 15h 40m. [As
indicated by the dotted line in diagram.] The light seems to be
composed of a great number of parallel bright streaks. This
appearance of striation is very decided in the region within two
degrees of the nucleus. The southern branch is curved and much
shorter and fainter than the stJ aight ray. The location of the
last degree of length represented in the sketch is very difficult.
The breadth here is estimated to be 30; or 40'. The bounding
lines are carefully laid in on the Durchmusteru?ig chart, and their
position relatively to stars frequently compared with the sky
during the progress of the sketch. Sky suddenly clouded at
14h 30m.

316 Scientific Intelligence.

SCIENTIFIC INTELLIGENCE.

I. Chemistry and Physios.

1. Velocity of Light. — Lord Raleigh discusses the recent pa-
per of Young and Forbes (Roy. Soc. Proa, May 17, 1881), in
which it is maintained that blue light travels in vacuo about 1*8
per cent faster than red light, and asks the question : what is really
determined by observations on the velocity of light? Is the
velocity of a single wave determined, or that of a group of waves?
If the group velocity be denoted by U and the wave velocity by

V, the relation between these velocities is explained by TJ= j_ ,

in which k is inversely proportional to the wave length. Accord-
ing to Young and Forbes, V varies with k and therefore TJ and V
are different. A complete knowledge of U, which can be obtained
by experiment, does not lead to a knowledge of V. Lord Ray-
leigh discusses the various methods employed in determining the
velocity of light and concludes that if we regard the solar parallax
as known, we obtain almost the same velocity of light from the
eclipses of Jupiter's satellites as from observation, although the
first result relates to the group velocity and the second to the
wave velocity. There cannot be, therefore, a difference of two or
three per cent between the group velocity and the wave velocity.
These considerations lead Lord Ray leigh to doubt the conclusions
of Young and Forbes. — Nature, Aug. 25, 1881, p. 382. j. t.

2. Movement of Sound Waves in Organ Pipes. — Dr. Rudolph
Koknig has contrived an ingenious arrangement which enables
one to observe the nodes and segments of a sound wave in its
passage through an organ pipe. The pipe is slotted along its en-
tire side, is then placed in a horizontal position with the slot be-
neath and resting in a trough of water. The water thus forms a
portion of the lower side of the pipe and the slot allows a hollow
glass tube, U-shaped, to be pushed along the interior throughout
its entire length. By connecting the glass tube with manometric
capsules, one can discover the position of the nodes and also ob-
serve peculiarities in the movements of the waves. — Ann. der
Physik und C/temie, No. 8, 1881. j. t.

3. On the Conductivity of Metals for Heat and Electricity.—
In the continuation of a paper on this subject, Herr L. Lorenz
discusses the theoretical laws of the cooling of metals when placed
in ordinary air and extends his observations to the conduction
of heat by metals in general. If T represents the absolute tem-
perature, k and x the conductivity for heat and electricity

• k

respectively, he is led to the following expression: — =TX

constant. According to his view there is discontinuity in the
interior of every body and there are regions or sections along
which free electricty can move without manifesting difference of

L. Boss— Tail of Comet b, 1881.

307

We then derive the following table of results :

Table II.

P
S
T

June 26.

Axis of right*
line tail
at end.

•7«3

•340

•210

•187

37°'0

31°'l

3456

361-2

351-8

102-9

W B M N

40-2

391

12-9

14-0

** «8.
O

June 28.

£3*

©♦■»•«
- 4> 0)

o 2".
OS .

3 «

•179
22°-9

"5-6

24-9
29 8

•775

•374

161

25°-0

848-6

350 8

106-1

540

5 6

July l.

•189
24°-7

" 8-7

30-0
32-1

•153
19°-2

3-7

34-4
270

•795

•428

•130

16°-4

3531

2-8

110-3

5T8

21-1

*2
a*

O so

— »
Ot«

110
10°4

18-6

32*9
41-5

313

July 22.

■4

fed

Sits

1-018

•853

0-82

5°0

577

615

1216

109*8

o a> a>

*£%

Mb*

067
3°-9

71-8

94- 1
24-9

An inspection of the foregoing table shows that the char-
acteristics of the two branches of the tail, as defined bv the val-
ues of ip , present a similarity quite as striking as could have
been predicted in view of the considerable probable errors to
which such determinations are liable. On the first. three dates
the cometocentric elevation of the earth above the plane of the
comet's orbit was, respectively, 13°, 16°, and 20° only ; so
that small errors in the observed position angle are consider-
ably multiplied when converted into the corresponding values
of«jp/. It must also be remembered that many of the points
observed are several degrees farther from the nucleus than the
superior limit of visibility assigned by most observers for the
extent of the tail on the respective dates.

If we examine similar computations which have been made
6n the tails of other great comets we see that the two branches
resemble the two types most frequently observed. The right-
line tail corresponds to the principal appendages of the great
comets of 1811, 1835 (Halley's), 1843, 1861, 1862, and others.
The genera] direction also conforms to that of the secondary
tail of the great comets of 1858, 1874 and others ; but in the
present case the light of this tail is relatively far more conspic-
uous. The branch of greater curvature finds its representa-
tive in the great majority of comets which have been observed.

298 A. E. Verrill — Marine Fauna occupying the outer banks

Ommastrephes iUecebrosus Verrill.

Stations 918, 919, 923-925, 939, 940, 949, 1025, 1033; 45-258
fathoms.

Taonius pavo (Lea.) Steenstrup.

Station 952 ; 388 fathoms. Two specimens. This rare
species has not been recorded from our coast, since it was de-
scribed by Lesueur, in 1821.

Rossia sublevis Verrill.

Stations 924, 925, 939, 945-947, 951, 952, 997, 1025, 1026,
1028, 1029, 1032, 1033; 106-388 fathoms. Some of the speci-
mens, recently obtained, agree more nearly with R. glaucopis
Lov., as figured by Gk O. Sars, than any seen before. It may
prove to be identical.

Heteroteuthis tenera Verrill.

Stations 918, 919, 920, 921, 922, 940, 944, 949, 950, 1026,
1027; 45-182 fathoms. Eggs of this species were taken at
stations 922, 940, 949, and in several localities in 1880. They
are nearly round, ivory-white or pearly, attached to shells, etc.,
by one side, in groups, or scattered. On the upper side there
is a small conical eminence.

Sepiola leucoptera Verrill.

Stations 947, 952, 998, 999, 1026 (8 juv.) ; 182-388 fathoms.

Octopus Bairdii Verrill.

Stations 925, 939, 945-947, 951, 952, 994, 997, 998, 1025,
1026, 1028, 1033, 1035; 103-388 fathoms.

composed of suckers, like the outer rows; but the horny parts had been de-
stroyed, in my specimen, and the hook-shaped form of the fleshy part of the
suckers was probably due to post-mortem changes. By careful treatment with
reagents I have been able to restore some of the distal ones more completely, so
as to show a distinctly sucker-like form.

It would, however, be difficult, without farther evidence, to believe that Gonatus
amcenus, as figured by G. O. Sars, is the young of this species, for he neither mentions
nor figures the remarkable series of lateral connective suckers and tubercles on the
tentacular clubs, though he gives detailed figures of the club and its other hooks
and suckers. That so careful an observer as Sars should have overlooked such a
structure seems almost incredible. The two small specimens that I have hitherto
seen from America, agreed well with Sars' figures, but both were considerably
injured from having been in fish -stomachs. A small specimen (mantle 30mm long)
recently taken by us, at station 1031, is, however, well preserved, and while
agreeing with G. arnanus in all other respects, it has the peculiar lateral connec-
tive suckers and tubercles of the club, seen in G. Fabricii, adult. These organs
are, however, very minute in this specimen, but sufficiently evident to convince
me that Steenstrup is correct in considering G. amoenus the young of G. Fabricii

Since Steenstrup has shown that the type of my genus Lestoteuthis is the same
genus as Gonatus (adult), and therefore that L. rdbustus (Dall), doubtfully referred
to it by me, is a distinct genus, I propose to make the latter the type of a new
genus: Moroteuthis. Its most prominent distinctive character will be the remark-
able solid cartilaginous cone, superadded to the end of the peu, and corresponding
in form and position with the solid cone of Belemniks.

off the southern coast of New England. 299

AUopo8us mollis Verrill.

Stations 937, 938, 952, 953, 994 ; 310-715 fathoms. Two
very large females were taken: one at station 937, in 506
fathoms; the other at 994, in. 368 fathoms. The former
weighed over 20 pounds. Length from end of body to tip of
1st pair of arms, 31 inches ; of 2d pair, 32 ; of 3d pair, 28 ; of
4th pair, 28 ; length of mantle beneath, 7 ; beak to end of 4th
pair of arms, 22; breadth of body, 8*5; breadth of head, 11 ;
diameter of eye, 2*5; of largest suckers, *38.

Among the northern species which had not been found pre-
viously south of Cape Cod, the following were dredged: Tro-
phon clathratus, 972, 976 ; Acirsa costulata (=borealis), 965 ;
Amauropsis Islandica (—helicoides) ; Margarita cinerea, 981 ;
Machceroplax bella, 1032 ; GyLichna Gouldii, 973 ; Odostomia
{Meiiestho) strtalula, 980.

Dolium Bairdii Verrill and Smith, sp. nov.

A moderately large species, having nearly the form of D.perdix
and D. zonatum. Male. Shell broad ovate, with seven broadly
rounded whorls ; spire elevated, apex acute ; nuclear whoris
about three, smooth ; suture impressed, but not deep, nor chan-
nelled, the last whorl is somewhat flattened (perhaps abnormally)
below the suture, for some distance, corresponding to an inward
flexure of the outer lip. Aperture elongated, irregularly
ovate ; outer lip regularly rounded, except for a short distance
posteriorly, where it is slightly incurved, its edge is excurved,
acute externally, distinctly but not prominently crenulated
within, except posteriorly, where a posterior canal is slightly
indicated ; columella straight ; canal short and broad. The
sculpture is peculiar : it consists of numerous (about 40 on the
last whorl) rather prominent, squarish, clearly defined revolv-
ing ribs, less than lmm broad, separated by interspaces of about

300 A. E. Verrill — Marine Fauna occupying the outer banks

the same breadth, in which there is usually one small narrow
rib, alternating with the larger ones ; sometimes there are two
or more small ones. The whole surface, both of ribs and inter-
spaces, is covered with fine and regular transverse, raised
lines. The surface is covered with a very thin pale olive-
yellow epidermis, easily deciduous when dry. Color white, ex-
cept that the larger ribs are alternately light brown and white,
and the apex, consisting of about three smooth nuclear whorls,
is dark brown. Length 68mm] breadth SB""1; length of aper-
ture 58™

The animal is well preserved. Proboscis blackish, exserted
about 20mm, thick (8°^) and clavate at the end, which is sur-
rounded by a sort of collar, with a finely wrinkled or crenulated,
white edge. Head large, with a prominent rounded lobe in
front Tentacles large, elongated (lO""*), stout, tapering, obtuse.
Eyes small, black, on distinct, but slightly raised tubercles at
the outer base of the tentacles. Head, tentacles and siphon-
tube dull brown. Penis very large (SO™ long, 12mm broad),
twisted and thickened at base, flattened distally, terminating in
a slightly prominent obtuse lobe at the tip; a well-marked
groove runs along the posterior edge to the tip.

Off Martha's Vineyard, station 945 ; 202 fathoms. Station
1036 ; 94 fathoms ; one young specimen and large fragments.

Pleurotoma (Bela) limacina Dall. (Daphnetta ?)

Bulletin Mus. Oomp. Zool., ix, p. 55, 1881.

Four living specimens of this elegant shell were taken at
station 994 ; 368 fathoms. Gulf of Mexico, 447-805 fathoms
(Dall). This is not a true Bela, for it has no operculum ; eyes
minute.

Caputw hungaricus (Linne).

Two living specimens were obtained, which appear to belong
to this species. They are more delicate and have somewhat
finer and more regular radiating ribs than the ordinary Euro-
pean form. It has not been recorded before from our coast

Stations 922, 1029 ; 69 and 458 fathoms.

Fiona nobilis Alder and Han.

British Nud. Moll., Solids©, Fam. 3, pi. 38A.

A large and handsome Fiona, apparently this species, was
found in two instances, in large numbers, on pieces of floating
timber, among Anatifers, at stations 935 and 995. They were
kept in confinement several days and laid numerous clusters of
eggs. These are in the form of a broad ribbon, spirally coiled
in about one and a half turns, so to form a bell-shaped or cup-
shaped form, and attached by a slender pedicel, so as to hang
from the under sides of objects. Alder and Hancock recorded
its occurrence, in a single instance, at Falmouth, England.

off the southern coast of New England. 301

Issa ramosa Verrill arid Emerton, sp. no v.

Gills five, arborescently branched. Color, pale yellow. The
dorsal tentacles darker.

The radula is quite different from that of I. lacera and Triopa
claviger. The median area is wide, with two rows of thin,
transversely oblong plates ; there are three rows of large, nearly
equal teeth on each side, with the tips strongly incurved, ob-
tuse ; the innermost tooth has a small lobe on the middle of the
inner edge ; these are followed by about seventeen or eighteen
smaller, oblong plates, with slightly emarginate anterior ends;
these gradually decrease in size toward the margins of the
radula.

Stations 940, 949 ; 130 and 100 fathoms.

In form, this resembles 1. lacera, but is easily distinguished
by the branched appendages along the sides.

Of the Lamellibranchiata, some very interesting new forms
occurred. The most important of these are species of Phola-
domya, Mytilvmerw and Diplodonta, — three genera not before
found on this coast. The Pholadomya is more related to cer-
tain fossil forms than to any of the few described living species.
The genus Mytilimeria has hitherto had very few living repre-
sentatives, and none of them resemble our very singular
species.

Among the northern forms, not previously found south of
Cape Cod, are the following: Mya truncate, ; Spisula ovalis
(975, 976, 981) ; Leda tenuisulcata (973) ; Nucula tenuis.

Pholadomya arata Verrill and Smith, sp. nov.

302 A. M Verrill — Marine Fauna off New England coast

posteriorly ; a small portion, near the tip of the posterior end is
covered only by slight ribs. The surface between the ribs is
finely granulated. When the thin superficial layer is removed
the surface is pearly. The umbos are prominent, strongly in-
curved, nearly or quite in contact. The binge in the right valve
consists of a small, slightly prominent lamella, running back as a
low ridge, and separated from the margin of the shell anteriorly,
and from the cartilage-lamina posteriorly, by a narrow groove;
the cartilage-pit is long, running forward under the beak as a
a narrow furrow ; it is bounded internally by a prominent
lamella. Length, 36mm; height, 29 ^j breadth, 26™.

Stations 940, 949, 950 : 69 to 130 fathoms.

Three specimens, all dead, but one is very fresh.

Mytilimeria flexuosa Verrill and Smith, sp. no v.

Shell obliquely cordate, short, higher than long, very swollen,
the anterior end rather shorter than the posterior; umbos very
prominent, beaks much incurved, pointed and turned forward,
with a small, deep concavity just under and in front of them.
The outline and surface of the shell is very flexuous, owing to
the broad deep grooves and elevated ribs which divide the sur-
face into several areas. The most prominent rib is very high
and rounded, and runs from the beak to the extreme ventral
margin, inclining somewhat forward ; in front of this the ante-
rior area is flattened with a wide shallow concave groove or
undulation in the middle, and others less marked; the front
edge is broadly rounded, slightly undulated below. The mid-
dle area is very elevated, and forms more than a third of the
shell ; it is flattened or slightly concave in the middle, and
undulated by several faint broad ribs ; it recedes posteriorly,
and a broad concave furrow separates it from the small poste-
rior area, which is without ribs, and has a prominent rounded
edge. The surface is finely granulated, lines of growth evident
The interior is pearly, angulated by a deep groove, correspond-
ing to the largest external rib. The dorsal hinge-line is nearly
straight posteriorly, and strongly incurved anteriorly, in the
right valve it projects inward, but not in the left; in the right
valve there is a small rounded tubercle, a little back of the
beak ; from below this a short rib-like process runs back below
the deep, partially internal cartilage-pit, which extends forward
and upward under the beak as a narrow furrow. Anterior
muscular scar deep; posterior one larger ovate, less distinct;
sinus small. Length, 25mm ; height, 26mm ; breadth from side
to side, 22mm.

Station 947 ; 312 fathoms. One pair of fresh valves, dead.

This and the preceding were both taken by means of the
"rake-dredge."

L. Boss— Tail of Cornel 6, 1881. 303

Diplodonta turgida Verrill and Smith, sp. nov.

Shell large for the genus, round-ovate, a little longer than
high, very swollen ; the two ends nearly equally rounded, the
interior a little narrower; ventral edge broadly and regularly
rounded; beaks nearly central, somewhat forward of the mid-
lie, strongly curved inward and forward, acute. Surface with-
out sculpture, smooth except for the evident lines of growth,
[n the right valve there are, opposite the beak, two nearly equal,
stout, sharp teeth, separated by a space of about the same
width; back of these, and partly joined at base to the posterior
)ne, there is a much larger, broad, stout, obtuse tooth, with a
groove on its dorsal side ; external cartilage-groove and its
amella are long and narrow, curved. Length, 29mm; height
umbos to ventral edge), 25mm; breadth, 23mm.

Station 950; 69 fathoms. One right valve.

Art. XLIL— Note on Hie Tail of Comet i, 1881 ; by Lewis

Boss. With Plates V and VI.

The changes which took place in the aspect of the tail of the
yreat comet of 1881, during the last days of June, seemed to
me of peculiar and unusual interest. Appearances so novel
and unexpected moved me to prepare some rude sketches of
the tail, with brief notes as to its position in the sky. From
several causes my opportunities for making such studies
proved to be very few, and lack of experience contributed to
diminish the completeness and accuracy of the results actually
obtained. It is to be regretted that the number of those who
give serious and systematic attention to this branch of obser-
vation is quite small in view of the small number of opportu-
nities; while, on the other hand, the observations which can
be made are uncertain in character, and the results vary much
with individual judgment. It is therefore important that
drawings and descriptions should be gathered from as many
sources as possible.

The engravings (Plate V), accompanying this paper were
reduced from drawings compiled from the original sketches
and notes.

304 L. Boss— Tail of Comet by 1881.

June 26, 10\ — Air wonderfully transparent. The tail of the
great comet consists of two branches. The principal branch
appears to be perfectly straight, and passes about two degrees to
the apparent east of Polaris and eight or ten degrees beyond it.
For the last ten or fifteen degrees this branch is exceedingly
faint. The other is curved quite strongly to the apparent west,
and after its separation from the principal ray requires most care-
ful scrutiny for its detection. It seems to extend to a point six
or seven degrees, astronomically southeast from Polaris.

June 26, 13h 30m. Sketch. — The tail presents to the naked eye
much the same appearance as it did earlier in the evening, except
that neither branch can be traced so far as then seen. The
straight branch appears to pass quite centrally over 2 T7rs«
Minoris, and to extend about two degrees beyond B. A. C. 7851.
Its breadth seems to be nearly uniform and a little more than one
degree. With the aid of a straight edge no curvature could be
safely assigned. There is a rather sudden falling off in brightness
at a point four or five degrees from 2 Ursse Minoris toward the
nucleus. The edges of this ray are ill-defined and the central
parts brightest. The ray which curves toward greater right
ascension is not satisfactorily seen. Its effect is to broaden and
intensify the principal ray for a distance from the nucleus equal
to about four-tenths the whole distance to Polaris. At this point
the total breadth of the tail is estimated to be about four degrees.
Here a separation is faintly indicated, but the continuation of the
curved ray is observed with extreme difficulty. The direction
and extent of this branch is indicated on the sketch.

June 28, 13b. Sketch. — Foggy haze low down in the north.
Sky otherwise satisfactory. The nearly straight ray described
on June 26 has dwindled to a faint and narrow streak, which
might have been overlooked, had not a bright one been expected
in its place. It extends to a point near 2 Ursa? Minoris as indi-
cated in the sketch. Its breadth is not over one-third of a degree.
The curved branch is brightest in its central parts, and is very
conspicuous for the first ten or fifteen degrees of its length, ft
seems to terminate about three degrees short of B. A. C. 4349;
though at times a much greater extent is suspected. Fifth mag-
nitude star (B. A. C. 2326) is 15' inside the following edge of the
tail. The axis of this branch passes to the apparent east of

L. Boss— Tail of Comet 6, 1881. 305

B. A. C. 4349, and at a distance from it equal to about one-fifth
the distance between that star and Polaris. The last direction of
the axis is toward /3 Ursa3 Minoris. The distance of Polaris from
the preceding edge of the tail is nearly equal to the distance
between Polaris and 2 Ursae Minoris. The breadth at three-
fourths the distance from the nucleus is about three degrees.

July 22, 14h. Sketch. — Four-inch Clark Comet seeker. Power
twelve. Field 2° 30'. Sky fine. * Two branches seen. The first
is nearly straight and brighter than the other. Estimated width
10'. This branch is certainly recognized as far as A. R. 14h 20m.
Sometimes I imagine that it extends as far as A. R. 15h 40,n. [As
indicated by the dotted line in diagram.] The light seems to be
composed of a great number of parallel bright streaks. This
appearance of striation is very decided in the region within two
degrees of the nucleus. The southern branch is curved and much
shorter and fainter than the straight ray. The location of the
last degree of length represented in the sketch is very difficult.
The breadth here is estimated to be 30' or 40'. The bounding
lines are carefully laid in on the I>urchmmterung chart, and their
position relatively to stars frequently compared with the sky
during the progress of the sketch. Sky suddenly clouded at
14h 30m.

306

L. Boss— Tail of Comet b, 188L

Table I.

June 26, 13h 30m
June 28, I3h 00
July 1, 12h 15m
July 22, -14* 00

Nucleus.

Axis, right-line tall.' Curved tail.

J | a

87°-2

57°9

316°

83°-0

99°

80°-5

» w — w

* 9 » —

132

856

— — — —

— — — •

90- 1

639

20-

859

155

860

• » — —

— — _ —

* — • —

— — — —

100

830

958

707

* ~ * *

111-2

87*0

* . _ m

» * — —

•■ * • ^

w w •• "

115-3

800

1776

81*9

215-4

828

205 0

822

Point in

curved tail

observed.

Axis.

Axis.
Prec edge.
Foil. edge.

Axis."

Convenient formulae have, been devised by Bessel (Astr.
Nachr., vol. xiii, p. 193), by the use of which we may determine
the angular deviation of a point in the tail from the radius
vector prolonged. It will be necessary ta assume that the axis
of the tail lies in the plane of the orbit of the nucleus. This
assumption is well supported both by theory and experience,
and is, no doubt, substantially correct. Such small deviations
as might result when emissions of matter from the head are
unsymmetrical with reference to the orbit plane, or when the
initial velocity of particles thrown off from the nucleus is
greater toward one pole of the orbit than toward the other, may
probably be neglected as comparatively insignificant. Let :

r=Radius vector of the nucleus at the time of observation.

p= Geocentric distance of nucleus.

A = Length of tail, or distance of point observed from the nucleus.

s= Angular length of tail.

p°= Position angle at the nucleus of r prolonged.

p= Corresponding angle for the observed point in the tail.

S=The cometocentric distance of the earth from the north pole

of the comet's orbit.
T= Cometocentric angle between the earth and the observed

point in the tail.
<p'=:The cometocentric angle between the observed point and the

radius vector prolonged, — positive, when this point is on

that side of the radius vector from which the comet has

been moving.

From the elements of Dr. Oppenheim (Astr. N., 2384), we
find for the coordinates of the north pole of the orbit of comet
6, referred to the equator,

A=192°09'. D=+23°46'.

L. Boss— Tail of Comet b, 1881.

307

We then derive the following table of results :

Table II.

June 26.

June 28.

July l.

July 22.

Axis of right-
line tafl
at end.

Axis of right-
line tail at
2 Urs. Min.

Axis of

curved tail

at end.

Axis of right-
line tail
at end.

Axis of

curved tall

at end.

Axis of curved

tail near
B. A. C. 2826.

Preceding
edge at end.

Following
edge at end.

Axis of right-
line tail
at end.

Axis of

curved

tail at end.

•763

•775

•795

1-018

m — — «

•340

m «• • •

» • — *

•374

•m mt » »

•428

• » » »

•853

- - - -

•210

•187

•179

161

•189

153

•130

110

0-82

067

37°0

31-1

22°9

25°0

24°-7

19°'2

16°'4

10°'4

5°0

3°9

3456

* _ * «

m • — -»

348 6

3531

• • « •

57-7

~ - _ _

3512

351-8

350 8

3-7

2-8

18-6

61*5

71-8

102*9

-• * m •

W W « «M

106-1

110*3

1216

. . _ ..

402

391

24*9

54-0

30-0

; 34-4

5T8 ! 32*9

109-8

94-1

12-9

14-0

29 8

5 6

32-1

270

211 i 41*5

249

313

An inspection of the foregoing table shows that the char-
acteristics of the two branches of the tail, as defined bv the val-
ues of ip', present a similarity quite as striking as could have
been predicted in view of the considerable probable errors to
which such determinations are liable. On the first. three dates
the cometocentric elevation of the earth above the plane of the
comet's orbit was, respectively, 13°, 16°, and 20° only ; so
that small errors in the observed position angle are consider-
ably multiplied when converted into the corresponding values
oftjp/. It must also be remembered that many of the points
observed are several degrees farther from the nucleus than the
superior limit of visibility assigned by most observers for the
extent of the tail on the respective dates.

If we examine similar computations which have been made
on the tails of other great comets we see that the two branches
resemble the two types most frequently observed. The right-
line tail corresponds to the principal appendages of the great
comets of 1811, 1835 (Halley's), 1843, 1861, 1862, and others.
The general direction also conforms to that of the secondary
tail of the great comets of 1858, 1874 and others ; but in the
present case the light of this tail is relatively far more conspic-
uous. The branch of greater curvature finds its representa-
tive in the great majority of comets which have been observed.

Comet of 1881.

082

6°*2

5°0

057

24*9

308 L. Boss— Tail of Comet 6, 1881.

The tail of the comet of 1807 presents most striking resem-
blance to this under discussion. On October 22, 1807, the
comet of that year had, generally speaking, the same position
in space as the present comet had on July 22. On that occa-
sion (Astr. Nachr., vol. xiii, p. 228), Bessel found two tails.
The first he considered to be nearly straight and in length
about 4'5°. The other was strongly curved, broader than the
first, and in length about H°. Dr. Bredichin (Mosc. Ann., vol. v,
pt 2, p. 56), has computed the value of <p' for the end of each
tail. This enables us. to compare the two descriptions in a very
satisfactory manner. We have —

Comet of 1807.

A p' s
For the right-line tail, - - '139 7°*9 4°5
For the curved tail, - - - 105 24*2 3*0

Allowing for the difference in values of A and r, the agree-
ment is quite within the probable errors of observation. It is
thus seen that there is great similarity in the physical appear-
ance of the two comets, as well as between the elements of their '
respective orbits. Since, in general, we have the greatest pos-
sible variety in the appearance of the tails of the comets, and
especially in the combination of tails of different types, we may
confidently say, that the very remarkable similarity above
shown furnishes another important fact, in addition to those
which already tend to indicate a common origin for the comets
of 1807 and 1881.

Sir Isaac Newton and others after him have shown that the
tail might be produced by a repulsive force emanating from the
sun, and acting on detached particles, which are continually
thrown out from the nucleus of all great comets. Bessel has
investigated formulae (Astr. Nachr., vol. xiii) which enabled
him to compute the repulsive force necessary to produce a tail
of the form actually observed in the case of Halley's comet
The repulsive force in these formulae is, of course, an implicit
function. Bessel's formulae are shown (Mosc. Ann., vol. v, pt
2) to give results which are but roughly approximate for large
distances from the nucleus. Professor Norton, Dr. Bredichin
and others have published formulae which are more rigorously
exact. In all these investigations it is supposed that a particle
projected from the nucleus is repelled by a force (1—f*) the re-
verse of the Newtonian. The effective force acting on the par-
ticle will be /i, and when combined with the tangential velocity
of the nucleus will cause it to describe a hyperbolic orbit This
hyperbola will be convex or concave to the sun, according as
(1— /*) is greater or less than unity. In the volumes of the Mos-
cow Annals, Dr. Bredichin presents a variety of reasearches
concerning the consequences to be deduced from this assump-
tion of repelling forces.

L. Boss— Tail of Comet 6, 1881. 309

He refers the tails of comets to three general types, distin-
guished by the value of (1—//) employed in their theoretical rep-
resentation. The value of (1—/*) (expressed in the Newtonian
unit) for Type I is 11-0 to 12*0 ; for Type II, about 1-3 ; for Type
III, 0'3, or less. The value of (1— fi) for Type II, however, is
found to vary considerably in different cases without losing
its distinctive character. It is possible to introduce the effect
due to the initial velocity of projection from the nucleus, and
this, of course, modifies the value of (1—//) which would other-
wise be assumed. This effect will evidently be proportionally
least in tails of Type I, and will increase in importance as the
value of (1— fi) is diminished. If we suppose particles to be
projected from the nucleus equally in all directions with equal
velocities, the effect will be mainly shown in the breadth of the
tail. Thus we invariably find tails of T;ype I to be narrow in
comparison with those of Type II, — a fact which finds satisfac-
tory explanation in the relatively small effect, which would be
.produced by the action of initial velocity, when the repelling
force is relatively very great. But since cometary emissions
appear to take place mostly on the side of the nucleus nearest
the sun, the assumption ot the value zero for initial velocity
will always render the value of (1—/*) computed from observa-
tion, too small.

It will be interesting to examine our observations of the tail
of comet b 1881, with a view to determining to what extent
they conform to. the normal types. In a preliminary discussion
like this, which is founded on few observations of small weight,
it will not be worth while to include the effect of initial velocity
of emission. When a great number of observations of the tail
and coma have been collected, it may be possible to arrive at
some satisfactory result in this direction. I have accordingly
computed the hyperbolic orbits of particles emitted from the
nucleus at various times (previous to the observations on the
tail), with values of (1—//) equal to '6, 1*0, 14 and 110. The
values of the radius vector and true parabolic anomaly of the
nucleus have been computed from the elements of Dr. Oppen-
heim, previously cited.

Let:

M = Date when a given particle is observed in the tail.
M'=Time of emission of that particle from the nucleus.
M"= Perihelion passage of the -particle.
E = Eccentricity of the hyperbolic orbit.
1= Angle between the radii vectores of the particle and nucleus
at the time M. For the particle referred to the nucleus,
this angle will evidently always be retrograde to the
motion of the nucleus.
A = Distance of the particle from the nucleus at the time, M.

310 L. Boss— Tail of Comet b, 1881.

t] = Length of perpendicular let fall from the particle on r pro-
duced at the time, M.
£ = Distance from the foot of that perpendicular to the nucleus.

<p = Angle whose sine is -J, or the angle between r prolonged and

the line joining the nucleus and particle at the time M.

As an example of the manner in which the theoretical lines
of Plate VI have been constructed, the results of computations
intended to represent the right-line tail of June 26*805 (Berlin
time) are subjoined. The value of (1— /*) is assumed to be 11*0;
and the hyperbolical orbits are computed for particles emitted
at perihelion, and for two designated dates subsequent to that
time. We have :

M' Juno 16510 Juno 18*510 June 20510

M" June 16*510 June 18359 June 20-205

log E 00792 0-0791 0-0788

I 4° 15' 2° 29' 1° 13'

A '284 -192 -110

£ -273 -187 '109

7} -077 -041 -018

<p 15°'7 12°-4 9°'5

From the values of J, £, and 37, the curve marked I in the
figure for June 26 (PI. VI) is constructed. From that curve we
derive by a graphic process the values of <p corresponding to
the observed values of J at two points in the tail on that date.
We thus have :

A ¥ ' 0

June 26-805 \ -210 12°-9 13°-2

Type I ( -187 14-0 12-3

The agreement between the values of (p* and <p is even closer
than could have reasonably been expected from the unavoid-
able probable error in the determination of <p'.

In the diagrams of Plate VI, the point N" represents the posi-
tion of the nucleus at the respective times of observation.
N R' is the radius vector prolonged. The curves N I are care-
fully constructed in the original diagrams from the computed
positions of two or more partic'es, when (!—//)= 11*0. The pre-
vious dates of emission were so chosen that one or more com-
puted points would fall near that which was actually observed.
The curves N II were constructed with (1— /i)=l*4, and may
represent the tail of Type II.' The intervals between dates
of emission and observation for like values of A are much
greater in this case than in that for tails of Type I. The curves
N II" are constructed with (1— //)=1*0 : and N III" for July
22, is based on (1— /x)=0'6. The dots enclosed in small circles
indicate the positions of points in the tail actually observed.

L. Bobs— Tail of Comet 6, 1881.

311

Table III.

Bate.

Type I. (l-#) = 110.

Type II.

Point

A
210

129

182

+ "3

Point
II'

•179

29-8

31*2

+-¥

(HO

June 26

+ 1-4

1-4

•187

14-0

12*3

-1-7

June 28

•101

5-6

11-0

+ 5-4

II,'

•189

32*1

328

+ ■»

1-4

•153

27*0

29-7

+ 2-7

1-4

July 1

ii,

•120

31-3

26-5

—4-8

1-4

July 22

•082

6'2

5*7

— -5

•057

24-9

12-

-13-

1-4

16-

— 9*

1-0

1 1 1

21-

— 4-

•6

A value of 04 for {I— ft) would give a fair approximation to the
tail of Type II as observed on July 22. Tne agreement of the
observed and the computed values of ip for the tail of the first
type is very satisfactory. The deviation of five degrees on
June 28 might easily be attributed to errors of observation on
an object which was so excessively faint; and it is quite prob-
able that the location of the end point was somewhat influenced
by the general direction of the tail nearer the nucleus where it
was brighter. Such an influence would tend to make the ob-
served value of <p too small. The two values of tpf best deter-
mined for Type I are the second and fourth of the table ; and
these both indicate that a smaller value of (1—//) should have
been employed.

With reference to the comparisons of observed and computed
(p in the tail of the second type, we do not expect an accord-
ance so satisfactory. The difficulties of observation were greater
with this branch of the tail, which was broad and faint at its
extremity ; and, furthermore, an error in location of this shorter
branch would have a greater influence upon the value of <p'.
The probable uncertainty in the value of <pr for the first three
dates I estimate at three or four degrees. On July 22 the
location of the shorter branch of the tail was extremely difficult ;
still I cannot think that the probable uncertainty in <p' is greater
than four or five degrees. This would make any value of (1— (jl)

Am. Jour. Sci.— Third Series, Vol. XXII, No. 130.— October, 1881.

312 L. Boss— Tail of Comet 6, 1881.

much greater than 0*6, extremely improbable for that date,
unless we suppose a high velocity of emission from the nu-
cleus mainly on the side nearest the sun. The particles seen
near the end of this branch of the tail must have left the nu-
cleus about July 4, and for portions nearer the bead at later
dates. We know that this period was one of great activity in
the nucleus, and it is reasonable to suppose that the velocities
of emission toward the sun were unusually great. It is worthy
of remark that the value of (p' obtained from BessePs observation
of the 1807 comet (Oct. 22) requires a value for (1—//) of about
0'6. (Mosc. Ann., vol. v, pt. 2, p. 56). We may, however, sup-
pose that the matter composing the tail of July 22, having been
exposed to a lower temperature at the time of emission than
that which prevailed at perihelion, was in a less finely divided
state. Then, on the theory of electrical repulsion, we should
expect to find a smaller repulsive force for the later date.

On the whole, the results which can be inferred from table
III in respect to the ratio of the repulsive forces concerned in
the genesis of the two tails, may be regarded as extremely
favorable to the hypothesis of Dr. Bredichin, viz : that the tail
of Type I is due to the presence of hydrogen in the comet, and
that of Type II to carbon. Granting this, we should have ex-
pected the traces of hydrogen in the spectrum of the comet to
have been very pronounced on June 26, or on dates immedi-
ately preceding. On June 28 and for a few days following
that date, we might look for a weakening of the hydrogen lines,
or, at least, a decided change in the character of that portion of
the spectrum. It must be confessed, however, that all reason-
ing in the premises must necessarily be vague and unsatisfac-
tory, since we do not know to what extent matter, in the state
in which it must exist to form the tail, contributes to the spec-
trum of those parts of the comet in the vicinity of the nucleus
and coma, where, alone, spectra have been successfully ob-
served.

The complete history of this comet, of the changes observed
in the nucleus and its surroundings and in the tail, with draw-
ings, measures and estimated dimensions of all parts will be ex-
tremely interesting. When collected and combined with results
of polariscopic and spectrum analysis, it will doubtless furnish
most valuable material bearing upon the true theory of the
constitution of comets. That such material exists in rare abun-
dance it is not permitted us to doubt ; and it is to be hoped that
no one who is in possession of definite results, however meager
in quantity, will hesitate to add them to the collection.

Dudley Observatory, September 8, 1881.

J. D. Dana — Geology of Westchester County, N. Y. 313

Art. XLIII. — Geological Relations of the Limestone Belts of
Westchester County, New York; by James D. Dana.

1. Section of the Mott Haven belt of Limestone on I22d St.,

New York Island.

As the outcrops of limestone on New York Island will soon be
graded away, I here supplement my notice of the 122d street
locality with a fuller account of the section there afforded, and a
figure representing it. The section is on the north side of this
street, and extends from Lexington avenue to the first dwelling
house — about 120 feet. There are three belts of limestone: a,
five feet wide ; b, seven feet ; and c, in view to the eastern limit
of the open lot, 32 feet. The band g looks, at first, as if it were
the westward dipping portion of a, but it is in reality a seam of
granite or granitoid gneiss, in the schist. The three limestone
masses a, b, c, appear here to be independent beds. But over the

gab c

open lot, thirty yards north of a, b, the limestone b widens
eastward, or toward a, to 25 feet, and only a thin layer of schist
separates it from the continuation of a; moreover the beds dip
eastward under the schist at an angle of only 45°. Forty feet
farther north, in the back yard of a house fronting on 123d street
(the next north), the western of the bands of limestone widens
in both directions, and, from a high westward dip on the west
side, bends over eastward to horizontality. From these facts it
is probable that a and b are the two sides of an anticlinal ; that
this anticlinal has its axis dipping northward, so that the inter-
vening and therefore underlying schist disappears to the north-
ward, while the limestone stratum becomes broadly exposed
between the overlying schist on the east and west. Some of the
schist on the corner of Lexington avenue and 123d street I found
to be fibrolitic. On 123d street, only schist is in sight; the middle
portion of the area, or that in the direction of the axis of the
anticlinal, is occupied by houses. Whether the limestone c is the
same stratum, brought up by a fault or flexure, or, as it seems to
be from its position and thickness, another, I cannot say. If
overlying, its continuation would naturally be looked for to the
westward, where it is not known to occur. The schist is much
rusted and its bedding poorly exposed: moreover, the outcrops
of limestone south of 122d street diifer widely from those on its
north side ; and for these reasons it is difficult to reach any posi-
tive stratigraphical conclusions.

This locality is on the western border of the Mott Haven lime-
stone belt. As to the eastern border, nothing is here indicated,
beyond this, that the limestone increases in amount to the east-
ward.

314 J. D'Dana — Geology of Westchester County, N. Yi

Mr. Stevens's figure of the section on 122d street, in the Annals
of the New York Lyceum, referred to on p. 432 of the last volume
of this Journal, is so very unlike what I have found at the place,
and agrees in so many points with that of the more western belt
on 132d street, of which also he speaks in the article, that I have
suspected it to be wrongly labelled.

2. Contact-phenomena in the Schist a?id Soda-granite of Cruger*s

and Stony Point.

In my remarks on the rocks at Cruger's and Stony Point I have
sustained the view that the contact-phenomena, as they may in a
literal sense be called, between the mica schist and soda-granite,
are not results of contact of the schist with a pasty or liquid rock.
I add here a few more words on this point.

The contact-phenomena are these. The mica schist changes,
over the interval of about 1,000 feet between the limestone stra-
tum on the south and the granite on the north, (1) from a nearly
even-bedded condition to a much-flexed one — it becoming bent up
to the northward in many places into close and deep zigzags ; (2)
from a finely crystalline state to a coarsely crystalline — in connec-
tion with which change there is an increase in the size and
abundance of garnets ; (3) from a garnetif erous mica schist, to a
staurolitic and fibrolitic mica schist, with also an increasing
abundance of garnets ; (4) from a near freedom from quartz
seams to a condition of crowded interlaraination with them ; and
(5) occasionally, near the granite, from its ordinary micaceous
and quartzose character to a feldspathic and gneissoid, in which
oligoclase occurs with the orthoclase and the constitution thus
approaches that of the granite. Besides the above, the granite
often contains (6) scattered garnets near the junction, and also
(7) both near and remote from the schist, numerous inclusions of
schist, many of them short fragments, others long, flexed, or
zigzag layers, parallel in position to the bedding of the schist
outside, some fading nearly into the granite and vein-like, others,
especially if staurolitic, having all the characters of such layers
in the outside schist.

The following considerations are believed to confirm the cor
rectness of the conclusion to which I have been led as to the
origin of these contact-phenomena.

(1) The zigzag flexures of the mica schist — a rock of great
firmness, rendered eminently so by its numerous quartzose inter-
laminations — must have been made at the time when its meta-
morphisra took place ; for their production after it was iu its solid
crystalline condition would be impossible, or, at least so without
its having every where evidence of fracturing.

(2) The zigzag and other flexures in the schist indicate that
great pressure was exerted from some direction against the
stratum of slate (and other strata of the series) under conditions
fitted to produce them. A yielding liquid or pasty rock, however
forcibly intruded, would be a very feeble agent for such work,
and would have afforded feeble resistance to pressure from other
agencies.

J. D. Dana — Geology of Westchester County, N. Y. 315

(3) The increase in the grade of metamorphism, sufficient
moisture being present, would have needed no other cause but an
increase in the degree of heat ; and this would have been, in any
case, a consequence of the increasing extent of the flexures or of
internal movements in the schist ; for the constituent minerals
consist only of the common ingredients of sediments, and increase
in abundance of garnets means little more than increase in amount
of iron.

(4) Staurolite and fibrolite are minerals that occur widely
distributed through mica schists ; and require for their formation,
not contact-conditions, but too little alkali with the silica and
alumina in the original bed-material to make a feldspar.

Whatever, then, the origin of the granite, the schist must have
been put into its present flexed condition before there was any
liquid or pasty rock in front of it. Further, whatever the schist
has of crystallization or of crystallized minerals may have been
produced independently of any such condition. Finally, the
above facts, and others mentioned under the head of contact
phenomena showing transitions between the two rocks, are
opposed to the idea that the granite is of exotic eruptive origin,
and are well explained on the view of simultaneous metamorphic
changes in two adjoining conformable sedimentary formations that
had some intermediate gradations and intercalations, in which the
granite-made portion passed to a pasty state and so became in
sonne places an intrusive rock.

The mica schist and the adjoining limestone are strata in a
great synclinal or anticlinal fold, and probably, as I have shown,
the former. But whether the fold be a synclinal or anticlinal,
the increase northward observed in the zigzag flexures and in the
metamorphism is increase toward the axial plane of the fold.
The minor zigzag flexures may have been the effect either of the
pressure that produced the great fold, or of the gravitation of the
mass after, it had been raised to a high angle — now 70°.

The facts at Stony Point are very similar to those at Cruger's.
Although in some points seeming to sustain quite strongly the
theory of direct eruptive origin, if viewed together with those of
Montrose Point and the Verplanck Peninsula, they lead, I believe,
to the same conclusion — that of a metamorphic origin alike for
the soda-granite, quartz-dioryte, noryte and ehrysolitic rocks. If
there has ever been an example of an igneous rock made through
the fusion of sedimentary beds, the cases above described may be
reasonably regarded as of this mode of origin.*

For the remainder of this Appendix see the supplementary
sheet at the close of this number, p. 327.

* One of the statements on page 201 of the article referred to I have to with-
draw— that relating to figure 4. The figure is correct as far so it goes : but I have
found, on a recent visit to the place, that the band is continued after another
fault, and is not a narrower one folded on itself.

316 Scientific Intelligence.

SCIENTIFIC INTELLIGENCE.

I. Chemistry asd Physics.

1. Velocity of Light. — Lord Raleigh discusses the recent pa-
per of Young and Forbes (Roy. Soc. Proc, May 17, 1881), in
which it is maintained that blue light travels in vacuo about 1*8
per cent faster than red light, and asks the question : what is really
determined by observations on the velocity of light? Is the
velocity of a single wave determined, or that of a group of waves ?
If the group velocity be denoted by U and the wave Telocity by

V, the relation between these Telocities is explained by U= _ ,

in which k is inversely proportional to the wave length. Accord-
ing to Young and Forbes, V varies with 1c and therefore U and V
are different. A complete knowledge of U, which can be obtained
by experiment, does not lead to a knowledge of V. Lord Ray-
leigh discusses the various methods employed in determining the
velocity of light and concludes that if we regard the solar parallax
as known, we obtain almost the same velocity of light from the
eclipses of Jupiter's satellites as from observation, although the
first result relates to the group velocity and the second to the
wave velocity. There cannot be, therefore, a difference of two or
three per cent between the group velocity and the wave velocity.
These considerations lead Lord Rayleigh to doubt the conclusions
of Young and Forbes. — Katurey Aug. 25, 1881, p. 382. j. t.

2. Movement of Sound Waves in Organ Pipes. — Dr. Rudolph
Koenig has contrived an ingenious arrangement which enables
one to observe the nodes and segments of a sound wave in its
passage through an organ pipe. The pipe is slotted along its en-
tire side, is then placed in a horizontal position with the slot be-
neath and resting in a trough of water. The water thus forms a
portion of the lower side of the pipe and the slot allows a hollow
glass tube, U-shaped, to be pushed along the interior throughout
its entire length. By connecting the glass tube with manometric
capsules, one can discover the position of the nodes and also ob-
serve peculiarities in the movements of the waves. — Ann. der
Physik und C/temie, No. 8, 1881. j. t.

3. On the Conductivity of Metals for Seat and Electricity. --
In the continuation of a paper on this subject, Herr L. Lorenz
discusses the theoretical laws of the cooling of metals when placed
in ordinary air and extends his observations to the conduction
of heat by metals in general. If T represents the absolute tem-
perature, k and x the conductivity for heat and electricity

• k

respectively, he is led to the following expression: — =TX

constant. According to his view there is discontinuity in the
interior of every body and there are regions or sections along
which free electricty can move without manifesting difference of

Chemistry and Physics. 317

potential or experiencing resistance. When the electricity passes
through these regions, electric potential is observed. The heat
state and the electrical state are interconvertible forms of energy,
manifested according to the state of the body. — Ann. der Physik
und Chemie, No. 8, 1881, p. 582. J. t.

4. Microphonic action of Selenium cells. — Dr. James Mosek,
led by the theory that one and the same ray of light may have
heating, chemical and luminous effects, has examined the behavior
of selenium under the influence of the electrical current. It was
found that ordinary electrical polarization was manifested by sele-
nium : with a cell composed of zinc, selenium and copper, a polari-
zation of about 0*4 volt, was observed and a current was obtained
long after it was separated from the primary battery. A careful
examination of the connections between selenium and copper in
the form of cells invented by Bell and Tainter, and modified by
others, showed that between the copper and the selenium there is
only a slight and imperfect contact. Moser therefore concludes
that the selenium photophone is a microphone, and is confirmed
in this belief by the action of the carbon photophone constructed
by Bell and Tainter, which consists of a zigzag line scratched on
a silver covered glass plate and covered with lamp-black. This
instrument acts like the thermoscope described by Mr. Hughes.
The illuminating rays of light are those which are especially ab-
sorbed by selenium, "only the absorbed rays cau produce changes
of volume and of shape and in this way influence the contact of
current-conducting parts." Selenium, therefore, is heated by light
and this heating effect makes the selenium cell act microphonic-
ally. The light may also produce certain chemical effects in the
interior of the selenium, which may contribute to the efficiency of
the cell. It was found that the resistance of certain pieces of selen-
ium increased instead of decreased when submitted to light. Dr.
Moser therefore sees no reason for separating selenium from other
bodies and ".no prospect of finding an unknown power or a new
relation of forces in this substance." — Phil. Mag., Sept., 1881,
p. 212. j. t.

5. On the stresses caused in the Interior of the Earth by the
Weight of Continents and Mountains; by G. H. Darwin, F.R.S.

— In this paper I have considered the subject of the solidity and
strength of the materials of which the earth is formed from a
point of view from which it does not seem to have been hitherto
discussed.

The first part of the paper is entirely devoted to a mathematical
investigation, based upon Sir William Thomson's well-known
paper on the rigidity of the earth.* The second part consists of
a summary and discussion of the preceding work.

The existence of dry land proves that the earth's surface is not
a figure of equilibrium appropriate for the diurnal rotation. Hence
the interior of the earth must be in a state of stress, and as
the land does not sink in, nor the sea-bed rise up, the materials

* "Thomson and Tait's Nat. Phil.," § 834, or " Phil. Trans.," 1863, p. 573.

Chemistry and Physics. 819

33 tons per square inch, and it would rupture if made of any
material excepting the finest steel.

The stresses produced by harmonic inequalities of high orders
are next considered. This is in effect the case of a series of
parallel mountains and valleys, corrugating a mean level surface
with an infinite series of parallel ridges and furrows.

It is found that the stress-difference depends only oh the depth
below the mean surface, and is independent of the position of the
point considered with regard to ridge and furrow.

Numerical calculation shows that if we take a series of moun-
tains, whose crests are 4000 meters, or about 13000 feet, above the
intermediate valley bottoms, formed of rock of specific gravity 2*8,
then the maximum stress-difference is 2*6 tons per square inch
(about the tenacity of cast tin); also if the mountain chains are
314 miles apart, the maximum stress-difference is reached at 50
miles below the mean surface.

The solution shows that the stress-difference is nil at the sur-
face. It is, however, only an approximate solution, for it will not
give the stresses actually in the mountain masses, but it gives
correct results at some three or four miles below the mean surface.

The cases of the harmonics of the 4th, 6th, 8th, 10th, aud 12th
orders are then considered ; and it is shown that, if we suppose
them to exist on a sphere of the mean density and dimensions of
the earth, and that the height of the elevation at the equator is
in each case 1500 meters above the mean level of the sphere, then
in each case the maximum stress-difference is about 4 tons per
square inch. This maximum is reached in the case of the 4th
harmonic at 1150 miles, and for the 12th at 350 miles, from the
earth's surface.

In the second part of the paper it is shown that the great
terrestrial inequalities, such as Africa, the Atlantic Ocean, and
America, are represented by an harmonic of the 4th order; aud
that, having regard to the mean density of the earth being about
twice that of superficial rocks, the height of the elevation is
to be taken as about 1500 meters.

Four tons per square inch is the crushing stress-difference of
the average granite, and accordingly it is- concluded that at 1000
miles from the earth's surface the materials of the earth must be
at least as strong as granite. A very closely analogous result is
also found from the discussion of the case in which the continent
has not the regular wavy character of the zonal harmonics, but
consists of an equatorial elevation with the rest of the spheroid
approximately spherical.

From this we may draw the conclusion, that either the materials
of the earth have about the strength of granite at 1000 miles from
the surface, or they have a much greater strength nearer to the
surface.

This investigation must be regarded as confirmatory of Sir
William Thomson's view, that the earth is solid nearly throughout
its whole mass. According to this view, the lava which issues

320 Scientific Intelligence.

from the volcanoes arises from the melting of solid rock, existing
at a very high temperature, at points where there is a diminution
of pressure, or else from comparatively small vesicles of rock in a
molten condition. — Proc. Roy. Soc, June, 1881.

6. Expansion of Cast Iron -while solidifying. — M. J. B. Han-
nay and Robert Axdebson have a paper on this subject in the
Proceedings of the Royal Society of Edinburgh for December,
1879 (p. 359). By trials in diiferent ways, the authors reach the
conclusion that "liquid cast iron expands at least 5*62 per cent of
its volume on freezing."

II. Geology and Natural History.

1. Origin of the Iron Ores of the Marquette District, lake
Superior; by M. E. Wadsworth. (Proc. Boston Soc. Nat. Hist,
xx, 470, March, 1880.) — After a few prefatory sentences, this
paper presents what are regarded as objections to the view of the
nietamorphic origin of the Archaean iron ores of Marquette, and
a brief mention of reasons for holding that of its eruptive origin.
The argument for their metamorphic origin, from the fact that
the ore is banded, conformably to the outside schists, with layers
of red jasper, and is often schistose in the same direction, is met
by the remark that this banding is strongly like the banding of
some rhyolites, thus making banding a character of more import-
ance than mineral constitution. To the argument for metamorph-
ism from original marsh-made beds, based on the fact that the ore
is in bed-like masses conformable with the bedding of the associated
schists, the author says — putting his objections in the unnecessary,
but with him common, form of ridicule, and shooting wide of the
real point at issue — that whoever advanced this theory " probably
intended it for a bit of facetiousness." " A dike passing through
slate must be sedimentary because the slate is sedimentary ! Do
we not find rocks intruded through sedimentary ones in every posi-
tion, both parallel with the stratification and oblique or perpen-
dicular to it ?" and then, with still more earnestness in his
misdirected logic, "Can any geologist ever have been so ignorant
of the mutual association of eruptive and sedimentary rocks as to
have soberly advanced the above idea ?" After discussing in this
style " all the evidence which we are aware has been used to
prove the sedimentary origin of the jaspilite and ore," Mr. Wads-
worth uses a still more personal method, the notice of which is
unnecessary.

Mr. Wadsworth, in his argument for an eruptive origin, which
follows, does not show that the iron ore and jasper are much like
eruptive rocks in mineral constitution, or give facts proving that
iron sesquioxide and silica, among the most infusible of minerals,
may come up side by side in a state of fusion, when ordinary
ejected rocks contain the iron and silica chiefly in fusible com-
binations ; he simply asserts, " as the prominent fact," " that
wherever the contact of these rocks with the country rock-
could be studied, that contact was always an eruptive one," of

Geology and Natural History. 321

which he says he is especially able to judge. There is nothing
else of as much importance as this, and on this point his infer-
ence is not confirmed by the writer's microscopic examination
of thin slices of the jasper and adjoining ore. No detailed
facts or sections, or descriptions of rock-slices, are given ; the
deficiency of the article in this respect is one of its remarkable
features. The author, after depreciating remarks about others,
mentions, in his paper, the several qualifications, — geological,
lithological, petrological, etc., — required for the model investi-
gator of the subject ; and, in contrast, the paper itself contains
no geological, lithological, or petrological details.

The paper closes with a statement of the author's ideas as to sci-
entific progress, part of which we cite, that the warning it conveys
may be circulated and duly heeded: "The day seems not so far
distant as might be supposed, when it will again be as necessary
to challenge the statements of those holding plutonic views as it
is now those holding neptunian ones. The popular belief in any
subject continually oscillates between different opinions like a
mighty pendulum, passing and repassing the point of truth. But,
strange fatality, if it stops at this point, all is stopped, the works
are dead. When truth is reached or discussion ends, stagnation
ensues. Again, when the pendulum vibrates, woe be to the man
who swings not with it. In all candor we ask geologists to stop
and think if the pendulum has not swung decidedly out of the
perpendicular on the sedimentary side? Ease up a little, brethren,
but do not swing back too far." — A head not out of the perpen-
dicular is plainly very desirable. j. d. d.

2. The Taconic rocks of the border of Lake Champlain. — Mr.
Jules Marcou has an important paper in the Bulletin of the Geo-
logical Society of France for Nov. 8, 1880 (III, ix, No. 1, 1881),
on the rocks of the northeastern border of Lake Champlain, referred
by Emmons to the Taconic System, and especially upon what he
regards as "colonies" in these rocks, using the term nearly as done
by Barrande, for " centres d'apparition d'etres precurseurs et de
types prophetiques." These Taconic slates have in part been re-
ferred, since Barrande's article on the fossils, to the Primordial or
Cambrian. The paper gives in detail the results of Mr. Marcou's
study of the beds near Georgia, St. Albans, Swanton and Highgate
Springs, and illustrates his conclusions on a colored geological map,
and also by means of a large plate of sections, which, together, will
be of much service to future students of the region. Ihe Taconic
rocks are stated to be older than, and also unconformable to, the
Potsdam sandstone. The apparent unconformabilities were ex-
plained by Logan on the ground of faults and displacements (Geol.
of Canada, 1863, pp. 844-861), and this has since been the gener-
ally accepted view. But Mr. Marcou reaches different conclusions,
and, by means of the idea of colonies, rids the subject, to his satis-
faction, of adverse paleontological evidence. The Georgia slates
contain the Primordial trilobites. lie describes, as next above,
the Phillip8burgh group, and this as passing above into the Swan-

322 Scientific Intelligence.

ton group, and both series of slates as including lenticular masses
or beds of limestone. These limestone masses contain the colonies,
and from the fossils they afford he concludes — taking one of his
lines of limestone beds as an example — that Billings's species
Lituites Famsworthi, L. Imperator, Nautilus Pomponius, Mur-
chisonia Vesta, Metoptoma Niobe, M. Orithya, Pleurotomaria
postuma, Maclurea matutina, M. ponderosa, Ecculiomphalus Can-
adensis, E. intortus. and E. spiralis, are part of the American Pri-
mordial fauna ; and to the same category he refers also, for a like
reason, species of Asaphus, Chzirurus, Calymene, Illainus, Trinu-
cleus, Phynchonella, Mui chisonia, etc. Thus the precursor species
are the actual species of the later Lower Silurian, colonized m the
remote Cambrian before the era of the Potsdam sandstone. This
application of the idea of colonies makes a jumble of the early
Paleozoic of America, instead of indicating the way out from diffi-
culties in certain regions of faulted and flexed metamorphic rocks.
No such scheme can take from Calciferous, Chazy and Trenton
fossils their value as tests of geological age, even if the question
as to the Taconic slates is involved therewith, unless it first be
substantiated by the study of the fossils in undisturbed strata.

3. Volcanic Eruption on Hawaii. A letter from the Rev.
Titus Coan to one of the editors, dated Hilo, Aug. 24, 1881. — The
stream of lava continued until it had reached within one mile of
the sea, and three-fourths of a mile of a well-peopled part of Hilo.
All at once the flow seemed to be checked, and, by the 10th of
this month, little or no vapors were seen along its channel, or
high up on the broader part of the stream, or about the summit
of the burning mountain. The blackened lavas of the eruption
cover about two square miles to an average depth of twenty-five
feet ; but this is only a rough estimate for no exact measurements
have as yet been made. We judge the length of the third stream
to be fifty miles, including all its deflections, and for the most of
this distauce it was, to all appearance, a surface stream.

4. Glacier /Scratches in Oos/ien in Northwestern Connecticut. —
Glacier scratches over the higher portions of New England are of
special interest because they give the direction of movement in the
ice free from the swervings due to the courses of valleys. The
higher lands of Goshen are particularly favorable in this respect.
Observations have been recently made by Mr. Henry Norton, of
Winsted, which we here cite. — On the west side of the mountain
(allowance having been made for magnetic variation), S. 41° E., but
with one deep one, 8. 77° E. ; farther south, in Mr. McElhane's
lot, several deep groovings 8. 38° E. — and pointing, northwest-
ward, directly toward Mt. Everett; south of the house, on the
same lot, S. 22f ° E. and S. 58° E.

5. Oil the /Structure and Affinities of the Genus Monticidipora
and its /Subgenera, with critical descriptions and illustrative species;
by II. Alleyne Nicholson, Prof. Nat. Hist. Univ. St. Andrews.
240 pp., large 8vo, with six plates and many wood cuts. 1881.
Edinburgh and London. (Wm. Blackwood & Sons.) — This vol-

Geology and Natural History. 323

ume, while not, as the author says, a monograph of this group of
fossil corals, contains a historical and critical review of previous
memoirs and conclusions on the subject, a discussion of the synon-
ymy as to genera and species; explanations of microscopic struc-
ture; inferences as to the affinities and zoological position of the
genus, and descriptions of several new species. The observations
are based mainly on specimens collected in the United States and
Great Britain. The volume bears evidence of much study and
research in its preparation, and of liberal expenditure by the pub-
lishers in its manufacture, and will be welcomed especially by
American paleontologists.

6. Ulexite in California; Note by W. P. Blake. (Communi-
cated.)— Ulexite occurs in quantity in Kern County, California, in
the bed of an extensive " salt marsh," a few miles north of Desert
Wells, and twenty miles from Mojave Station on the railway.

7. Worked Shells in New England Shell-Heaps ; by Edward
S. Morse. — Mr. Morse called attention to the fact that hereto-
fore no worked shells had been discovered in the New England
shell-heaps. A similar absence of worked shells had been noticed
in the Japanese shell-heaps. Worked shells were not uncommon
in the shell-heaps of Florida and California. Mr. Morse then
exhibited specimens of the large beach cockle (Lunatia) which
showed unmistakable signs of having been worked. The work
consisted in cutting out a portion of the outer whorl near the
suture. To show that this portion could not be artificially broken
he exhibited naturally broken shells of the same species, both
recent and ancient, in which the fractures were entirely unlike
the worked shells. — Abstract of paper read before the Anter.
Assoc, at Cincinnati.

8. Changes in My a and Lunatia since the deposition of the
New England Shell-Heaps ; by Edward S. Morse. — This com-
munication embraced a comparison between the shells peculiar to
the ancient deposits made by the Indians along the coast of New
England, and similar species living on the coast at the present
time. He referred to similar comparisons which he had made in
Japan, wherein he had found marked changes to have taken
place ; changes which showed that the proportions of the shells
had greatly altered.

He had made a large number of measurements of shells from a
few shell-heaps of Maine and Massachusetts, and had obtained
very interesting results. The common clam (My a) from the
shell-heaps of Goose Island, Maine, Ipswich, Mass., and Marble-
head, Mass., in comparison with recent forms of the same species,
collected in the immediate vicinity of these ancient deposits,
showed that the ancient specimens were higher in comparison
with their length than the recent specimens.

A comparison of the common beach cockle (Lunatia) from the
shell-heaps of Marblehead, Mass., showed that the present form
had a more depressed spire than the recent forms living on the
shore to-day, and this variation was in accordance with observa-
tions he had made on a similar species in Japan. — lb.

32-t Scientific Intelligence.

9. Beitrdge zur Morphologie und Physiologie der Pilze, Vterte
Reihe ; by A. DeBary and M. Woronin. — After an interval of
not far from ten years, the important series of papers by DeBary
and Woronin, published under the above title in the AbhandL
Senckenb. Gesellsch., is continued in a fourth part which contains
a paper by DeBary on Investigations on the Peronosporea* and
Saprolegniew and the formation of a Natural System of Fungi.
The article covers 137 quarto pages, with six lithographic plates.
The subject is treated under sixteen different heads, of which the
first twelve are devoted to an account of different forms of Py-
thium, Phytophthora, Peronospora, Saprolegnia, Achlya and
Aphanomyces. With the exception of some hitherto un described
species, the writer has confined himself principally to the changes
which occur in the formation of the oogonia and antheridia, giving
with great minuteness the details of the process of fertilization.
In the genera like Pythium and Peronospora where only one
oospore is produced in an oogonium, the oospore is separated from
the oogonium wall by a layer of protoplasm to which DeBary
gives the name of peri plasma, and he thinks that the markings
formed on the outer coat of certain oospores is formed directly
from the peri plasma, and is not an exudation from the cellulose
wall of the spore itself. In Pythium a small process, or befruch-
tungsslauch, penetrates the oogonium wall, and reaches the
oospore. In this process DeBary distinguishes a thin homogen-
eous layer lining the wall, which he calls periplasma, while to the
thicker axial portion he gives the name of gonoplasma. The act of
fertilization consists, in Pythium, of the escape of the gonoplasma
through the open end of the process and its union with the oospore.
In Phytophthora and Peronospora during the act of fertilization
some of the contents of the antheridium pass apparently into the
oospore, but the transfer is by no means as marked as in Pythium,
and the matter which escapes from the antheridial process consists
of only a few granules and the whole axial portion does not escape
as in Pythium.

In Saprolegnia and 'Achlya nothing could be seen to be dis-
charged from the antheridial tubes and the fertilization consists
merely in the contact of the male filaments with the surface of the
oospores. Contrary to the view advanced by Pringsheim, DeBary
finds that the thin spots in the oogonium walls of some species,
and the papillae found in others, have no direct connection with
the antheridial tubes which may penetrate the oogonium walls in
any place. It has long been known that in some of the Sapro-
legnecjp, oogonia are found in which the oospores apparently
ripen, although antheridia are wanting. It has been suggested
that in such cases antheridia were actually present but had been
overlooked. DeBary agrees with Pringsheim in affirming that in
some cases oospores ripen without the presence of antheridia.
He differs with Pringsheim, however, in considering such forms to
be distinct species rather than accidental variations of species in
which antheridia normally occur. He does not "deny that forms

Geology and Natural History. 325

with antheridia and forms without them may have originally been
derived from a single species, but cultures continued for two years
showed that forms without antheridia constantly reproduced them-
selves, and they are, according to DeBary, instances of apogamous
reproduction.

The fifteenth section treats of the systematic position of the
Peronosporece and Saprolegniew. In the former order is included
Pythium. The last section, to which, in a certain sense, all the
others are merely introductory, is a valuable discussion of the rela-
tion of the different orders of fungi to one another, and to some
extent of the algae. Apparently, DeBary is not willing to go as
far as Sachs in giving up the general distinction of algae and fungi,
although recognizing their close relationship. Starting with the
Peronosporece, he considers that a series can be formed, on the one
hand, by that order, the Ascomycetes, and the Uredinecp, the last
named order being connected with the Basidioi/iycetes by the
TremettinL A second series is formed by the Saprolegniece, Chy-
tridem and Ustilaginece. With regard to the sexuality of Fungi,
DeBary expresses himself in rather a conservative manner and
considers that in some cases, as in certain Ascomycetes, sexual re-
production seems to be out of the question, and he is inclined to
regard the spores in several groups to be of apogamous origin.

w. G. FARLOW.

10. Fauna ' und Flora des Oolfesvon Neapel; IV Monographic:
Corallina ; by Professor Solms-Laubach. Leipzig, 1881. — This
small folio of 64 pages with three lithographic plates is the first
botanical contribution which has been issued in the form of a sep-
arate memoir, although several botanical papers have appeared in
the Mittheilungen of the Zoological Station at Naples, and Reinke
has published two papers on the Cutleriaoece and Dictyotacece of
the Bay of Naples in the Nova Acta. Twenty pages are devoted
to an enumeration of the Corallines in the region of Naples; includ-
ing five genera, and twenty-five species. The specific account is
followed by a chapter on the conformation of the organs of vegeta-
tion as a basis of generic distinctions. It is incidentally stated
that the so-called heterocysts described by Rosanoff in Melobesia
farinosa are really the spots from which hairs are given off, and
according to Solms they are found also in M. callithamnioides
and Lithophyllum insidiosum. The third chapter contains a
minute account of the development of the fruit of Corallina
mediterranean with notes with regard to the fruit in some other
species. The present writer does not accept the account given by
Thuret of the difference in the cystocarps of Corallina and Jania
but unites the two genera. In regard to the sperrnatozoids be
maintains in opposition to Thuret that they are not naked but
have a distinct wall comparable to that of the spermatia of
fungi. The spores are borne on what Solms calls a fusion-cell, a
structure found in all the order examined. The closing chapter
has observations on the fructification of Amphiroa, Melobesia,
Lithophyllum and Lithothamnion. An interesting account is given

326 Miscellaneous Intelligence.

of the t hallos and fruit of M. Thuretii, the carious parasite on
species of Coraffina, and a similar parasite, M. deformans, is
described by Solms from Australia. A formation of gemmae, not
elsewhere known in the order, is described and figured in Mel.
callithamnioides. w. 6. f.

11. The Botanical Collectors Handbook ; by W. Whitman
Bailey. (G. A. Bates, Salem.) — This volume forms number three
of the Naturalist's Handy Series, and contains full directions for
the collection of all kinds of plants and their proper preparation
for, and the arrangment in the herbarium. The writer has been
aided in his account of the method of collecting cryptogams, by
notes from experts in different departments, and there is a chapter
by Mr. C. HL Feck on the preparation of fungi. At the end is a
short account of the principal public herbaria in this country and
a list of books relating to the floras of different countries. The
book is illustrated by wood-cuts. w. g. f.

III. Miscellaneous Scientific Intelligence.

1. Ancient Japanese Bronze Bells; by Edward S. Morse. —
Mr. Morse described the so-called Japanese bronxe bells which
are dug up in Japan. These bells had been described and figured
by Professor Monroe in the Proceedings of the New York
Academy of Sciences. Mr. Kan da, an eminent Japanese archae-
ologist had questioned their being bells from their peculiar struc-
ture. Mr. Morse had seen a number of different kinds of bells,
some of considerable antiquity, but none of them approached
these so-called bronze bells. Mr. Kanda had suggested that they
were the ornaments which were formerly hung from the corners
of pagoda roofs. But the fact that none of them showed signs
of wear at the point of support, reudered this suggestion unten-
able. Mr. John Robinson, of Salem, the author of a work on
Ferns, had given the first suggestion as to the possible use of
these objects. He had asked why they may not have been covers
to incense burners.

Curiously enough old incense burners are dug up which have
the same oval shape that a section of the bell shows. The bell
has openings at the base and also at the sides and top, so that the
smoke of burning incense might escape. It is quite evident that
these objects are neither bells nor pagoda ornaments and this
suggestion of Mr. Robinson's may possibly lead to some clue re-
garding their origin. — Abstract of paper read before the Amer.
Assoc, at Cincinnati.

Primitive Industry, or Illustrations of the Handiwork in Stone, Bone and Clay of
the Native Races of the Northern Atlantic Seabord of America* by Charles C.
Abbott M.D. 560 pp.. with many illustrations. Salem, Mass., 1881. (George
A. Bates). — A notice of this excellent work, aud also of the following, is deferred
to another number.

Report on the Geology and Resources of the Black Hills of Dakota! by H.
Newton and "SV. P. Jenney : U. S. Geographical and Geological Survey of the
Rocky Mountain Region, J. W. Powell in charge. 566 pp. 4 to., with plates and
a folio atlas. Washington, 1880.

APPENDIX.

Art. XLIV. — Appendix to Paper on the Geological Relations
of the Limestone belts of Westchester County ^ New York; by
James D. Dana.*

3. The rocks and their observed positions in Westchester County

and New York Island.

In the following notes, the abbreviations used are: Av. Avenue ;
St., Street ; calc, calcareous ; I. limestone ; gn., gneiss (variety
without excess of mica) ; thin gn., thin schistose gneiss ; m. mica-
ceous, mica; m. gn., micaceous gneiss; m. sch., mica schist; hard
gn., hard or compact thick-bedded gneiss ; hbl., hornblende ;
hblc.y hornblendic; N., north ; S., south ; E., east ; W., west ; R.,
river; R.R., railroad; var., varying. In giving the strike and
dip, the words strike, dip, are omitted ; N. 20° E., 70° E. signifies
strike N. 20° E., dip 70° to the eastward, and so throughout. As
heretofore, the courses are corrected for magnetic variation. The
courses and dip given are those corresponding to the T-symbols
on the maps at the places mentioned; and where there is no T-
symbol on the map, the course and dip is put in brackets. The
maps referred to are that of Westchester County in volume xx,
numbered Plate V, and that of Westchester County and northern
New York Island, in volume xxi, numbered Plate xix.

1. On New York Island.

A. East of 4th Avenue. — W. of 3d Av., 100 yds. from 4th, on I02d St.,
gn. and m. gn. N. 40° E., 90°, 80°-70° E., and again 70 yds. from 4th Av., on
102d St, N. 46° E. (varying), 80° E. ; S.W. corner of 3d Av. and 103d St., m. gn.
N. 22°-39° E., 70°-80° E., 90°, 80° W. to 60° W. ; cor. Lexington Av. and 103d
St., m. gn. N. 38° E., 65° E., N. 39° E., 85° E., with a twist to E. and W., and
dip S. of 60°, much hblc. where beds most contorted.

Near 123d St and Av. A, on East River, m. gn. N. 26° E., 60° W., the outcrop
under water at high tide. — N.W. corner 120th St. and Lexington Av., m. gn. N.
26°-28° E., undulating; 122d St., E. of Lexington Av., N. side of St., I. N.
26°-28° E., 90°, 70°-45° E. ; in E. part of open lot, bending to N. 55" E, (see
above) ; [On 123d St., northeast part of same open lot m. sch. N. 31° E., 80° E.] ;
[W. side of Lexington Av., S. of 124th St., N. 26° E., 70°]. E. side of 4th A v.,
S. of 118th St., I. in m. gn. N. 27°-32° E., 90°, 80° W. S.E. corner of 130th St.
and 4th Av., m. sch. and gn., N. 26° K., undulating, dip 0°-90°, mostly 50°-70°.

B. Between 4th and 6th Avenues. — W. of 4th Av., on 102d St, S. side,
m. gn. N. 21° E., contorted, 90°, 70° W., N. side 50 yds. from Madison Av., N.
29° E , 70°-80° W. ; N. of 117th St., between Madison Av. and 4th Av., gneissic I.
X. 28° E., 70°-50° E. ; W. of Madison Av., m. gn. horizontal and undulating;
W. of W. corner of 5th Av. and 120th St., S. of Mt Morris Park, garnetif. m. gn.

♦This paper is contained in volumes xx'to xxii of this Journal.
Am. Jour. Sot.— Third Series. Vol. XXII, No. 130.— October, 1881.
22

328 e7. D. Dana — Geology of Westchester County r, N. Y.

N. 28° E., 50°-65° W. ; 120th St., S. of S.W. angle of same Park, 400 feet E. of
corner, m. gn. N. 17°-22° E., 45° E., and 250 feet E. of comer, 50°-70° W.j W.
of 4th A v., either side of 120th St., m. gn. contorted, N. 27° E., undulating, and
S. of 125th St., m. gn. N. 26° E., 65°-70° E.

In Mt. Morris Park, m. gn. N. 30°-32° E. ; N. 30c-34° E.; 60c~70° E. ; N.
45° E., 60°-70° E. ; [also in S. part, fronting 5th Av., m. gn. N. 30° E.f 75°-80°
E., also in zigzags].

Between 131st Stand 133d St., N. side of 132d St., 1. N. 20°-28° E., dip
undulating, E. and W. but mostly E„ and S. side of 132d St., I. over open lot and
half way to 131st St., N. 24°-28° E., 90° or nearly; and to E. m. sch. N. 23°-32°
E. (28° average), undulating, large contortions.

C. Between 6th and 8th Avenues.— In Central Park N. 32°-27° R, 70°-75°
E., but much contorted. Along 7th Av., at S.E. corner of 138th St., m. gn. N. 34°
R, 70° E.; near 139th St., N. 37° E., 65°-70° E.; 140th St., N. 30° R, 70° E. ;
near 145th St., N. 26° R, 80° R; N. of 149th St, N. 26°-28° R, 80°-85° E.;
[also, near 154th St, gn. and m. gn. N. 31°-33° E., 70°-80° E., 90°].

D. Between 8th and 10th Avenues, South op 155th Street. — On 9th Av.,
near 104th St., m. gn. N. 29° E., 10°-60° E.; E. of 9th Av. on 110th St., N.
27°-32° E., 80° E.; W. of 9th Ave. on 1 10th St.. m. gn. N. 34° R, 80°-9O°, con-
torted and much hblc.

East side of rocky part of Morning Side Park in line of 115th St., m. gn. N.
22°-29° E., 65° W.-900, hblc. layers; same, farther N., nearly to line of 117th St.,
N. 37°-40° R, 60°-75° E., large slabs cleaved off and slid down the bluff; [same,
in lino of 117th St., N. 34°-37° R, 70°-80° W. to 90° and 85° R ;] same, in line
of 118th St, 70 yds. W. of 9th Av., N. 42° E., 90°, 80° E. to 80° W. Just W. of
Morning Side Park, five observations commencing at the most southern, m. gn. N.
24° EM 60° W.; N. 293 E., 80° W. to 90°; N. 34° R 90° ± ; N. 33° R, 90° ± ;
N. 33° E., 90° ±.

On St Nicholas Av. and 125th St., X. 28° E, 90° ±; same Av., along Convent
Grounds, between 126th and 129th Sts., N. 27° E , 90°, some hblc. and near 126th
St granite veins, and above 129th St. N. 30°-31° R, 70° W., var. to 60° W. On
S. part of Convent Grounds N. 22° E., 50° R On S.W. part of Convent Grounds,
three observations, N. 22° E. average, 65° W., var. to 50° and 70° W. ; W. part
of same grounds, near the fence, m. sch. and m. gn. N. 30° E., 70° W. Near N".
end of same grounds N. 32° E., 70°-60° E., and near its middle, m. gn. N. 27° R,
70°-75° E. On St. Nicholas Av.. near 138th St., m. gn. and m. sch. N. 33° R,
80° W. to 80° E., mostly E. ; near 144th St. N. 32°-37°-27° E., 70° R, much
contorted; near 145th St N. 26° E., 90° and to E. of last on 145th St., N. 30° E.,
90°, 80° E.

E. Between 8th and 10th Avenues. North of 155th Street. — At 156th St
N. 14° R, 70°-80° W., N. 28° R, 75° W.— 16lst St., N. 19° E., 80c-65° W.—
Between 161^t St. and reservoir, N. 24° R, 80°-65° W., N. 38° R, 80° E. to 90°,
N. 19° E., 80" W.— Near river, below reservoir, N. 20° R, 70° W.— Within 120
rods N. of reservoir, along 10th Av., N. 28° E.. 70°-80° E. ; N. 29° R, 65°-70°
(varying to 50°) E. ; On slope toward river, N. 30° E., 80° W. to 90° ; N. 30° E.,
90°; N. 37° E., 80° E. to 90°.— Between 120 and 180 rods N. of reservoir, along
10th Av., N. 19° E., 80°-85° E. (var.), N. 23°-24° R, 80° E. to 90°; On slope
toward river, N. 27° E., 90° E. ; N. 38° E., 80°-70° W.; N. 30° E., 90°; N. 31°
E., 80° W.— Farther N. on 10th Av., S. of Sherman's Creek, N. 21°-32° R,
80° E. to 80° W. (west side of road); large granite veins; N. 7°-22° E., 60° R
to 70° E. (east side of road); [west side of road nearly opposite, N. 22°-7° E., 50°
E. to 65° W., and varying just south to 70° W. and 20° W.] ; N. 55° R, 35°-30°
E. (E. side of road); N. 83° W. to 72° E., 30°-40° E. (E. of road); N. 27°-32° R,
65°-70° W. (on top of ridge).— Farther N.E. toward Sherman's Creek, N". 8° W.,
50° W. (40°-60°); N. 12° E., 65°-70° W.

F. On or West op 10th Avenue, South op 155th Street. — Near 10th Av.
S. of 125th St., m. gn. N. 30° R, 80°-75° E. ; N.E. corner of 130th St. and Broad-
way, N. 29°-30° E., 80° E. to 90° : On 10th A v., N. of 133d St., N. 26° E., 75°-65°
R, and near 136th St., N. 32° R,'75° E. to 90°.

On Uth A v.. N.W. corner with 131st St. under house, m. gn. N. 28° E., 80° B.
to 90°; on 132d St, m. gn. N. 23°-25° R, 90°; W. of 11th Av., on N. side of
133d St, N. 23°-30° R, 90° to 8° W.— In "Park," near corner 10th Av. and

J. J). Dana — Qeoloyy of Westchester County, N, Y. 329

133d St., m. gn. N. 20° B., 90°, 80° E., and near 11th Av., N. 28° KM 70° E., and
in line of 136th St., N. 39° E., 50° E. (varying to N. 55° W., 35° W.-On 11th
Av., N. of 157th St., N. 30° E., 80° E. (average); in lino of 137th St., N. 19° E.,
70° W. to 80° E.; same Av. and 148th St., m. sch. to thin m. gn., N. 25° E., 1*0°,
80° E.; same Av., but nearly half way to 10th, above 145th St., N. 28° E.,
80°-75w E.; [same Av. and 147th St, E. side, N. 28° E., 85° W. to 85° E.].

G. On or West op 10th Avenue, and on or North op 155th Street. — On
11th Av. near 160th St., N. 22°-30° E., 70°-65° E. ; [same Av. and 161st
St., S.W. corner, N. 26° E., 90°-70c E.] ; same Av., 102d St, N. 28° E.,
90°-80° E.; [same Av., 163d St., N.E. corner, N. 29° E., 90°-80° E.] ; same
Av. and 164th St., N.E. corner, N. 29° E., 90°-80° E. Near junction of 11th
Av. and Kingsbridge Road, N. 17° E., 90°. On Kingsbridge road and 165th
St., m. gn. N. 29° E., 90°; same and 187th St., N. 29" K., 65° E. Near Hud-
son River, 155th St., 100 yds. off, m. gn., N. 14°-22° E., 90°, 80° E. On Hudsou
R. railroad, nearly in line of 163d St, N. 22-24° E., 70°-80° E., var. beyond
to 55° E.; on R.R., W. of Deaf and Dumb Inst, dip 65° W.; on R. R., W. of
lust, for Blind, N. 24° E., 70J E.; on R.R., 100 yds. S. of Ft. Washington Sta-
tion, m. gn. N. 22° E., 60u-70° E. ; on R.R., just N. of Ft. Washington Station,
N. 31° E. to N. 37°, 60°, 70°, 55° E. ; on R. R., 150 yds. farther, m. gn. N.,
N. 20° E., 70° E. varying to 60° E. ; on R. R., 500 yds. S. of Inwood Station,
m. sch. N. 23° E., 70° E. ; on R.R., 200 yds. S. of Inwood Station, m. gn. N. 23°
E., N. 20°-30° E., 70c-65" E.; same, adjoining station, N. 34° E. Just E. of
Inwood Station, m. gn. N. 49 E., 55 °-65° E., but on N. side of road, N. 33° E.,
60°-70° E.

H. North op Sherman's Creek and Inwood Street. — W. of Farmer's Bridgo
over Harlem, S. of Kiugsbridge, /. N. 12° E., N. 32° E., N. 37° W., best N. 32°
E , dip 90° to 80° W. ; going S., just S. of first orook-crossing, I. N. 24° E., 75°
E. to 90°; 180 vds. farther S., I. N. 38° E., 75c E. to 90°; farther S., positions of
next 4 T-symbols, on W. side Kingsbridge Road, /. N. 47° E., 50° to 60° E. ; N.
60° E., 60°-65° E. ; N. 75° E., 45° E. ; N. 55° E., 75° E. Over 100 yds. W. of
Kingsbridge Road, at loc. of the northern of 3 T-symbols, N. 50° E., 60° E. ; at
loc. of other 2, N. 67° E., 55°-05° E. (varjing to N. 75° E.).

At Inwood St., a bed of m. sch. in /., and E. side of Kingsbridge road, m. sch.
N. 60 E., 60° E.; here 150 yds. E. of Kingsbridge road I. N. 58° E., 60° E.;
farther S., W. of head of Sherman's Creek, I. N. 40°-43° E., 60°-70° E. ; 350 yds.
S. of head of Sherman's Creek I. N. 38° E., 65° E. (most southern outcrop ob-
served).— On Inwood Parade Grounds N. of Sherman's Creek, 4 T-symbols, com-
mencing with the easternmost, /. N. 7-16° E., 70° E. ; N. 22°-27° E., 70° E. ; N.
1 7° K. 60°-65° E. ; N. 48u E., 70" E. (At the more eastern outcrops a large granite
vein in the limestone, having the course N. 15° E., corresponding with the strike
of the enclosing /. and also an intercalated bed of m. sch., having the strike N.
12°-32° E., dip 70°-80° E.

2. Outside of New York Island, in Westchester County.
On or near Limestone Area No. I.

a. South of \±8th St. and E. of 3d Avenue. — E. of Brook Av., in 133d St., m.
gn. N. 24°-32° EM 80° E. to 90°; on St. Ann's A v. in 136th St., I. N. 37" E., N.
32°-35° E., 80° W. to 80° E., near 138th St., /. N. 32° E., 80° E.; [in 14uth St., E.
of St. Ann's Av., m. gn. N. 26'-28° E., 90°]: between 142d and 143d St., I. N.
22° E., 75c E.; in 143d St., I. N. 17° E., 75° E. ; in 146th St., N. 22° E., 90°.—
Between Brook Av. and Willis Av., N. of 134th St., m. gn. about N. 22° E., undu-
lating, J5°-20° E., and to eastward N. 37° E., 65° E., and N. of 135th St., m. gn.
N. 37° E.. 40° W., varying much ; N. of 136th St., near the I. belt, gn. N. 31°-37°
E., 80° W. to 80° E.; between 139th and 140th St., N. 24° E., 75° E.

Port Morris, E. of R.R., m. gn. or sch. with many granite veins and much con-
tortion, best N. 29° E., 70°-75° E. ; W. of R.R., same, N. 27° E., 75° W.— N.
of Port Morris, E. of Boulevard on branch R.R., m. sch. or gn., N. 28°-47° E.,
60°-70c W, but varying much; still muny granite veins; W. of Boulevard, W. of
last, S. of 144th St. on R.R., N. 28°-24" E., 60°-70° W.

330 J. D. Dana — Geology of Westchestei' County, W. Y.

b. South of 148to St., and West of 3d Avenue, about Mott Haven. — E. of R.R., I
N. 26°-34°— 15° E., 90°, 70° W., much contorted; [on 8. side of N. ledge of 1, m.
soh. N. 25° E., 75° W.]— W. of R.R., S. of station, ledge of to. gn. and m. sch., N.
26° E.f 60°-80° W. ; on 138th St., W. of /., to. gn. N. 24°-32° E., 60° W., [and 50
yds. farther N., N. 17° E., 80°-60° W.]— N. of Mott Haven Station, N. of 13Rth
St., along R.R., I. N. 18°-20° E., 90° to 70° W., and 100 yds. N. of station, I N.
20° E., 50°-70° W., to. sch. in I. rusting from pyrite present; on 144th St., W. of
Mott Av., to. gn. N. 14° E., 60° W., and N. 22° E., 70° W.

c. Between 148th Street and 163d Street — W. of Harlem R.R., between Mott
Av. bridge over Hudson River R.R. and Harlem R.R., I. N. 15° E.. 60° to 80°
W. and E., 1. extending 520 feet W. of R.R. ; at the bridge and W. of it m. sch.
and to. gn. much contorted N. 22°-32° E., 26°-80° W., local flexures; N. of
bridge, gn. observed to be fibrolitic ; 250 yds. N. of bridge on Mott Av., to. gn.
N. 24° E., 70° W. [E. of Mott Av.. 100 yds. N. of junction of the two R.R., in a
small hill, I. N. 13-18° E.] ; E. of St. Ann's Av., near 149th St, N. 23° E., 90°
to 60° W.

On Harlem R.R., below 158th St., I., and near 160th St., N. 22°-27° E., 90°, to 30°
W., E. of Harlem R.R., and W. of 3d Av., on 149th St., /. N. 22° E., 35°-45° W.; near
150th St., larjre undulations, N. 22° E., 0°-45° W. and E. ; just below 155th St,
W. side of Elton Av., /. N. 22° E., 0°, 20° to 30° W., and E. side of same Av., L
N. 22° E., 35° W. to nearlv horizontal and 50° E.; on 156th St., E. side Elton
Av., I. N. 19° E., 45°-25° E. and horizontal; above 159th St. on Elton Av., I
N. 18° E., 35°-60° W., and W. of Av., N. 22° E.— 150 yds. E. of St. Ann's Av.
near 149th St., to. gn. N. 23° E., 60° W. to 90° [161st St, I. N. 22°-28° E.,
90°-30° W.] ; [162d St., 100 yds. W. of Harlem R.R., I. N. 24°-26° E., 70° W.

d. North of 163d Sfreet, East of Harlem R.R. — South of Tremont on 1 67th St,
near Washington Av., I. N. 19°-15° R, 80° W. to 80° E.); on 166th St., 100 feet
E. of Washington Av., I. N. 19° E., 70° E.; between 167th and 168th Sts., W. of
same Av., /. N. 20° E , 70° E. ; 40 feet E. of the Av., /. N. 26° E., 90° to 80° E.—
Just E. of 3d Av. on Boston Av., m. gn. N. 21° E., varying to N. 27° E., 60°-70°
E.; on 167th St, thin m. gn. N. 15° E., 70°-80° E.; on 169th St., N. side, just
W. of Fulton Av., m. sch. or gn. N. 14° E., 70°-60° E., varying much. — In Tre-
mont, W. of 3d Av., near 170th St, I. N. 27° E., 90°; on 172d St., N. 28° E., 90°;
farther N., I N. 21° E., 90° to 70° E. ; To eastward on Locust Av., E. of 3d
Av., m. gn. and sch. N. 18°-29° E., 90°-70° E. [E. of Bronx R. in West Farms,
to. gn. N. 18° K., 70° E.].— Half way from Tremout to Fordham, E. of Fordhamor
3d Av., to. sch. N. 21° E., 90°-75° E.

In Fordham, I. near R.R. station, E. side of Kingsbridge road, strike not dis-
tinct in the small outcrop.

N. of 163d St. and West of Harlem R.R. — In Fordham, on road going W., gn.
N. 28° E., 90° to 80° E., and 200 yds. farther W., N. 28° E., 90°; S. of last
on 1st road.W. of R.R., gray gn., with some to. gn., N. 26° E., 70° E. and N. 29°
E., 70° W. ; \ mile and farther S.W. just W. of same road, observations corres-
pnding to 8 T-symbols in succession, N. 30° E., 70° E. and N. 30° E., 75°-80° W.,
the easterly predominating; N. 30° E., 70° E.; N. 30° E., 90° to 80° E. and N.
30° E., 90° to 80° W. ; N. 26° E., 60°-75° W. ; N. 29° E., 80° W. ; W. of Tremont
Station gn. partly hblc., N. 22° E., 40°-60° W., varying to 30°.— S.W. of Tremont,
just W. of limestone area, observations corresponding to 5 T-symbols, qvartzytie
gn. mostly, varying to to. gn. N. 24° E., 90°-70° E.; N. 27° E., 60°-40° W.; N.
21° E., 60°-30° W.; N. 31° E., varying W. dip.; N. 18° E., 70*-60° W., but
varying much.

In Fleetwood Park, N.E. side, to. gn. undulating ; in E. part of ledge, N. 28° K.,
dip 60° E., but just W. bends over and dip 45° W., then 50°-80° E. again; W.
part of same ledge, N. 16°-22°-24° E., 75c-55° W.— In center of the Park, I. N.
24° E., 75° W.; 75 yds. more to W., 1. N. 28°-30° W., 60°-65° W.; to N.W. of
last, near schist of W. side of Park, I. N. 28°-30° E., 60°-70° W. ; W. part of
Park, to. gn., near I, N. 28° E., 65° W. ; farther S.W., m. gn. N. 32° E., &5°-M°
W.

W. of Fleetwood Park, near W. entrance, m. gn. N. 24°-26° E., 70°- 80° W. ; 200
yds. N.E. of last, on Av. adjoining Park, to. gn. N. 26° E., 70°-80° W. ; same road
farther N. in line with N. side of Park, to. gn., N. 8" E., 80° E. to 80* W.— And

J. D. Dana — Geology of Westchester County, N. Y. 331

N. 13° E., 90° about; 250 yds. N. of Park, m. gn. N. 26° E., 85° W.; near N.
end of this schist on Arcularius St. and same A v., m. gn. N. 20° E., 90° ±. and
50 yds. more to W., N. 19° K., 70° W. (T-symbol wrongly makes it E.).

Just N. of Fleetwood Park, I. (continuation of that of the Park), observations
corresponding to 5 symbols, N. 22° E., 90°; N. 18° E., 90° ±; N. 18° E., 90°:
N. 19° E., 70°-80° W., N. 19° E., 80° W:, the last near end of the gneiss
a little beyond line of Arcularius line : here the limestone becomes that of Area
No. 2.

Area No. 2 and its vicinity. — Commencing at the north \ mile N. of Manhattan

House (M on map), on Central Av., W. side, m. gn. N. 82" E., 50°-65° E. ; 300

yds. N.W. of same house on same Av., m. gn. N. 27° E., 65° E. ; 100 yds. W. of

same house on road going W.. m. gn. N. 30° E.. varying, 55°-60° K., and 400 yds.

farther W., N. 30° K., 65°-70* E.. varying; 400 yds. N. W. of Club Hou?e (C on

. map), m. sch. N. 28° E., 50°-60° K. ; [800 yds. S.W. of same, N. 23° E., 50°-60°

E.].— In Mt. Eden limestone regiou, 3 T-symbols, N. 12° E., 70°-80° W.. (near a

barn), N. 2° EM 60° W., N. 2"-12° E.; 45°-20° E., undulating: and to S.E., 4

; T-symbols, N. 17° E, 60° W.; X. 12° E., 60° W.. N. 27° E., 60°-65° W., N. 31°

■ E., 70°-65° (the last near bottom of valley west of Mt. Eden region) ; [again,

near last, N. 21° K.]
? Near head of Cromwell's Creek (the bay E. of lower part of Central Av.). and

where Central Av. crosses the brook, W. of brook, on road going N.W., m. gn. N.
]2°-19° E , 60°-65° E.; N. 14° E., 55° E., some hbk. layers; [near the last, W. of
\ road, near house, N. 21°-23° E., 65°-70° W.]; little to S. on Central Av., W.
[ side, m. gn. N. 31° E., 68° E.— East of brook (and •« Judge Smith's House"), L N.
\ 24° E., 40° E.; N. 27° E., 36°-40° E.; more to E. near limit of l, I. N. 21° E.,
! 60°-65° E. ; and E. of last, m. gn., N. 21° E., G5°-70° E. (the T-symbols of last
t two observations wrong in the stem pointing \V.).— W. of middle of Cromwell's
r Creek, on Central Av., W. side, m. gn., N. 23° E., 65°-75° E.: toS. of last, N. 32°
> BM 80° W. to 90°.

E. of S. part of Cromwell's Creek, on 1st St., /. N. 16° E., 90° ±; 225 yds. to
N.E. of bridge, thick bedded /., N. 16° E.; just E. of last, gn. N. 15° E., 80° W.
to 90°.— W. of S. part of samo Creek: at W. end of bridge, m. gn. N. 20° E.,
45°-60° W. ; on Central Av. below High St. near Case's Hotel, m. gn. much con-
torted N. 27° W. to N. 27° J?., 30° W. to 65° W.; directly W., 150 yds. N. of
McComb's bridge, m. gn. in zigzags N. 28° E., 80° W. to 80° E.; on Central Av.
150 yds. N.E. ©f same bridge, dip 00° to 80° W. On Hudson River, W. of N.
end of same bridge, 75 yds. W. of the Av., gn. N. 27° E., 80° E. to 65° E., and
120 yds. to N., near same river N. 27° E., 75° E. to 90°.

Area No. 3 and its vicinity.— At Kingsbridgo, on R.R., I. N. 37°-40°E., 60° K. ;
just W. of the limestone area, on R.R., m. sch. or m. gn.. partly hblc. N. 42° E.,
65°-70° E. ; 250 yds. W. near bridge at W. side of the bond in Sp. Duyvil Creek,
m. gn., N. 56° E., 70°-60° E. (here layer of actinolite, etc.). W. side of Tibbit's
Brook, 4 to 5 miles N. of Kingsbridge, m. gn. N. 18°-24° E., 60° E.

Area (No. 3A) nortu of Spuyten Duyvil to Riverdale, on the Hudson.
— At Spuyten Duyvil, near old R.R. station, m. gn. N. 40°-75c E., 35°-60J E.,
contorted, varying widely; 60 yds. S., N. 50°-37° E., 45°-50° E.; 50 feet N. of
forking of R.R. above same R.R. station, m. gn. and gn. N. 47° E., 70° E. ; about
200 yds. N.N.E. of last, and as far from river, m. gn. with some I., N. 47° E., 60°
E. ; on Whiting estate, S. of E. of an old limekiln. I. quarried, N. 17° E., 70° E., but
varyiug in strike and dip; 250 vds. N.E., gn. of E. side of I. area, part hblc, N.
4°-8° E., 55°-60° E.: [S. of Delafield's, gn., part hblc., N. 10° E., 60° E., 55°-65°
E.]; W. of same, large quarrv of /., part tremolitic, N. 10°-18° E., 60°-70° E. ;
E. of Riverdale station, N. of \ area, m. gn. N. 30°-34° E., 65° E. ; [S.E. of Mt. S.
, Vincent grounds, quarries of m. gn., N. 34° E., 60°-55° E. ; on R.R. near Mt. St.
Vincent depot, N. 17°-22° E., 55°-65° E.].

Area 4 — S. of W. Mt. Vernon £ mile, W. side of R.R., I. N. 29° E., 70° E. ; E.
of R.R., I. same ; E. of I., thin gn., samo ; on ridge between W. Mt. Vernon and Mt.
Vernon, thin gn. N. 21°-25° K., 70°-75° E. ; on N. Y. R.R., below Mt. Vernon,
thin or m. gn. N. 27° E., 65°-70° W.; at W. Mt. Vermon, K. of R.R., w. gn., N.

332 e/. J). Dana — Geology of Westchester County r, N. Y.

20° E., 65°-75° W., and W. of Bronx River near Williams Bridge, thick gn. N.
20° E., 90° to 80° W. ; m. sch. and m. gn. on W. side of R.R., S. of Woodlawn,
N. 18° E., 82° K; at Williams Bridge, W. of R.R. track, m. sch. N. 20° E.,
60° E., and E. of river, same.

Area 5. — In New Rochelle, N. of Davenport's Neck and of the Serpentine
loc., thin m. gn. N. 19° E. and N. ^7°-38° E., 85° B. to 85° W.; on S.E. and S.
shore of Davenport's Neck, S. of Serpentine loc., m. gn. N. 27°-43° E., 70°-85°
E. ; between N. Rochelle and Mt. Vernon, to the K., m. gn. (but partly whitish
gneiss), to Jhe W., m. sch. aud m. gn., N. 20° E. (average) 90°, the 8 T-eymbols
on map correspond, commencing on the east, to N. 25° E., 90° ; N. 2-4° K, 90°;
N. 21° E., 85° W., N. 20° E., 85° W.; N. 27° E., 85° W.; N. 15°-25° E., 9O3-80°
W.; N. 20° E., 78° W.; N. 21°-25° E., 70° W.

In Marmaroneck, m. gn., near R.R. depot, N. 37° E., 70°-85° W. ; the 4 T-
symbols to N.W. correspond to N. 39° EM 80°-85° W.. rock same; N. 37° E.,
90°. 80°-85° E., hard gn. ; N. 29^ E., 80°-85° E., hard gn.; N. 29° E., 80°-85° R,
same hard gn. ; N.W. of last, in Scarsdale, m. gn., N. 17° E., 90°-70° W. — South
of New Rochelle the 7 T-symbols correspond to: m. sch. or m. gn. N. 24° E., 90°
and 85° E. to 85° W.; same, dip 80° E. ; N. 22°-32° E., 70°-80° E., much con-
torted; N. 18° E. (average), 80° E.; N. 24°-30° E., 90°, 85° E.; N. 27°-30° E.;
N. 37°-47° E., 90° ±; N. 30° E., 90°; N. 24° E., 90° to 80° E.; N. 20°-23° E.,
80° E. to 90°.

Area 6. — At Portchester, thin m. gn. (brilliant mica scales white and black,
white predominating), N. 10°-12° E., 65°-70° E.; N. of Portchester, m. gn. N.
10°-18° E., 70°-75° E.; N. 7C-12° E., 60° E.; W. of Serpentine, N. 11° B., 90°,
N. 21°-27° E., 75°-80° W., N. 14° E.— 3 miles N. of Portchester, same m. g*.
N. 37°-67° E., 22°-42° W.— W. of Glenviile. same brilliant m. gn., N. 32° E.,
30° W.; N. 37°-76° E.; 30°-50° W. ; N. 37° E., 30° W.— N. of Serpentine area
m. gn. N. 37° E., 30°-35° W.; S. of Serpentine area, N. 17°-58° W., 30°-50° E.,
but with great contortion var. to N. 24° W., dip 30°-45°-50° E.; farther &, just
N. of R. R., N. 20° E. (but var. much), 65°-70° E.

Areas 7, 8. — m. sch. or m. gn., E. of Yonkers, N. 16° B., 70° E.; N. of last,
W. of river, and of N. end of cemetery, N. 12°-37° E., 55°-60° E. ; ± mile more
to N., N. 32° E., 60°-70° E. ; Yonkers to R.R. south of Bronxville, the 5 T-sym-
bols, thin m. sch. N. 15° E., 65° E. ; gn. N. 27° E., 85° W. ; same, N. 27°-30° E.,
65°-70° W.; thin m. gn. N. 24°-27° E., var. to N. 14° E. and N. 38°E., 90° to
85° W.

Area 9.—/. N. 10° E., 86° W. ; W. of I., thin m. gn. N. 18°-] 9° E., 85° E.-850 W.

Area 10. — The Tuckahoe belt extends little S. of bridge at Bronxville; E. of
river, S. and N. of R.R. depot, hard gn., contorted, N. 23°-26° E., 90°-70° E.,
85" \\\; W. side of river, near bridge, gn. N. 20° E., »i0c W.; \ mile N. of depot
on R.R., gn. N. 23° E. ; W. of this point in the marsh of the valley, I. N. 26° &,
90"; 50 yds. N., 1. outcrops E. of R.R.— West of Bronx R., between Bronxville
and Tuckahoe depot, hard gn., N. 20°-24c E.. dip W.; 1st, I. quarry N. of
Tuckahoe depot, I N. 35° E.: 65° W.; E. of I. is m. sch., N. 35° E., 60°-70° W.

Area 11.— In Scarsdale, along R.R., N. and S. of depot, /. N. 26°-28° E. [also
N. 10°-35° E.]. 55°-60° W. ; \ mile E. of depot., hard gn., and some hH.
schist, N. 26° E. (var. to 40°), 60°-80° W. ; agaiu, £ mile S.E. from depot m. gn.
N. 28 J E., dip 65 c W. The I. N. of depot a very narrow strip; narrow valley
continues toward Hartsdale. | mile N. of Scarsdale depot, W. of river, /. near
river, which continues N. through Fox Chapel Garden grouuds, 75-100 yds. wide;
granitoid gn. E. of l, N. 18°-28c E., dip 60°-65° W.—ln Hartsdale, in road going
E from depot, /. N. 18° E., 45° W., but ± mile E. of depot, m. sch., N. 18°-24c IL,
dip 60-65° W. and $ mile W., whitish gn., N. 17°-19° E., 60° W.— From Harte-
dale nearly to White Plains a narrow marsh along east side of river.

Area 12. — 1£ mile N. of White Plains, outcrop of I. from beneath stratified
drift, N. 13° E., 46° W.; 400 yds. N. of railroad station at White Plains, banded
gn., partly hblc, N. 30°-H7° E., but var. to N. 42°, 56°, 72° E.; 2 miles E., on road
tu Rye Pond, firm gn., X. 22 E. to N. 50°-60c W. ; £ mile farther N.K., reddish
granitoid gn., N. 27°-42° K., 50° W.; nearer Rye Pond, gray gn. much contorted. §fc

J. D. Dana — Geology of Westchester County, N. Y. 333

Area 13.— East of Dobbs Ferry, hard gn. N. 3°-22° E. and N. 11° E., 90° ; at
Ashford, hbk. gn. N. 25° E., 60°--70° E.; i mile E. of Hastings, hard gn. N. 17°
EM 90o-80o E.; 1 mile E. of Hastings, near Sawmill R., gn. N. 24° E., 65° E.

Area 14. — About 3 miles N. of Ashford I commences, the rock in the valley

there dark gray gn.; $ mile N. of this, I N.^2° E., 80° E.; at E. Tarrytown, \

'. mile E. of river, on E. border of the broad valley, I. X. 32° WM 45° E. ; again N.

'*• 28°-33° E., 90° to 80° E.; W. of river, is compact gn., contorted, N. 27°-32° E..

F dip 60° E.; E. of river, 1 mile N. of E. Tarrytown, a bluff of I. to east of

■ road, N. 47° E., dip 70° W.; i mile S.W. of Unionville L N. 24° E., 70° W.
' to 70° E., the latter prevailing.

■ Abba 15.— 275 yds. S. of Unionville depot, E. of R.R., I. N. 24° E., dip 75°
I E. Tn Pleasantville, S. of R.R. depot, /. N. 37° E., 60° to 80° E., here an intercalated
[ bed of m. seh.; 50 yds. N. of depot, I. N. 30°-34° E., 90° to 70° W.; £ mile E.

of depot, on "Broadway," I. N. 18° E., 80°, and more to N. dip 40° E.; E. of /.
I mile, thin gn., N. 40°-43° E., 90° to 80° E. At Chappaqua, I. about 250 yds.
in width. l| miles E. of Pleasantville depot, an outcrop of 7 , N. 3° E., 50° W.,
area small; W. of I, m. gn. N. 12° E., 70° W.; 1| mile S.E. of /. toward Armonk,
grayish gn. N. 9° E., 55° W.

Abba 16.— S. of Sing Sing R.R. station, I. N. 37° E., dip 55° EM again N.
30°-42° E., 70°-80c E.; near N. end of prison, I. N. 32° E., 40°-50°-60° E.; K.
of prison, on Spring St., I. N. 24° W., 20°-30° E. Abreast of station, m. sch. N.
25°-40° E., 70°-80° E.; S. of I area, in Scarborough, rn. gn. N. 23°-40° E.,
50°-60° E.— Along brook near entrance to Dale Cemetery, I. N. 20° E., 40° ; ^-f
mile E. of last, near road to Camp Woods, I. N. 64° E., 40° E. ; £ mile N. of
entrance to Cemetery, on road, m. sch. N. 54°-74° E., 90° to 80° E., contorted; in
field 60 yds. W. of last, same m. sch. N. 30°-38° E., with I. either side N. 37° E.
— W. of Dale Cemetery, above junction of Post road with road next E., I. N. 32°
E., 50° E., and W. on aqueduct, I. N. 58c E., with bed of granitoid gn. N. 58° E.,
65° E.

Area 18.— At Croton, 1 mile E. of R.R. station, 250 yds. S. of Barlow's, I. N.
24° WM 60° E.; near last, £ mile N.E. of Episcopal Church, fine-grained /. quar-
ried, but bedding indistinct; £ mile farther N.K., m. sch. N. 2° E., 60° K.

Area 19. — J mile S. of Croton R. at Huntersville, I. N. 52° E. ; W. of I., rusting
m. sch. tf. 52° E., 90°-80° E. ; aj?ain S.W. for | mile, I. N. 52°-60° E.; toward
Quaker Bridge, I N. 77° E., 85° K. to 90° and 85° W.

Area 20.— At Merritt's Corners, I. N. 36°-44° E., 60° E. ; 1 mile N., gn. N.
42° B., 70° E.

Area 21. — On east side of Croton Lake, coarse cryst. 1. mostly N. 7°-22° E.,
contorted, average N. 14° E., 60° W.-90, I. contains graphite; gn. on east side of
I, contorted (mica black), N. to N. 30° E. average N. 14° E., 55°-60° W. ; I. extends
into lake.

Area 22.— E. and S. of depot, I. much contorted, N. 12°-40° E., dip W.: 200
yds. S., N. 62°-67° W.; dip E. farther south, N. 40°-42° E.. dip W. ; on hill to
E., m. sch., with granite, N. 40° E., 50° W., again, m. sch. and gn. N. 37°-42° E.,
45° W.

Area 23.— 1 mile N. of south extremity of area, /. N. 8° W. to N. 10° E.,
60°-65° W., varying to 40° W. ; gn. in contact with I. and conformable, the gn.
partly hard feldspathic; W. border of river-valley, gn. N. 5°-ll° E., 40°-60° W.
Near S. end of area, and for 1 mile E, m. sch. and thin gn. N. 10°-11° E.,
40°-60° W.— East of 'Armonk, E. of Byram R., I. N. to N. 5°*E., W\ 60°; i mile
S.W. of Armonk schistose gn. N. 15° E., 55° W. [Between this point and
Kensifo depot, going S.W., X. of Kensico village, hard whitish to reddish gneiss,
N. 12°-22° E., 90°±; N. 14°-40° E., 90°-80° W.; S. of Kensico village, hard
gray gn. (black mica) N. 12° E., 60° W., same, N. H°-27° E.].— Near N. ex-
tremity, just W. of Byram Lake, twisted gn., X. toN. 60°-38° W., N. 7° E.; N.E.
border of lake, thin whittish gn. N. 8° W., N. 22° E., 45° W., contorted, again
thin gn. N. 2° E., again dipping under last thick bedded feldspathic partly banded

334 J. D. Dana — Geology of Westchester County, N. Y.

and giioissoid; again £ mile E., thin gn. N. 8° W., 40°-45° W., some KbL portions.
No I. in sight, being two feet under water in lake.

Area 24.— S.W. of area, gn. N. 24° E., 40° W.; S.E. of area, gn, N. 8° W.,
50° W. ; W. of valley, I mile N. of S. end of area, m. gn. (mica black), N. 8° W. to N.
22° E., varying to N. 67° E., 10°-35° W. In Bedford village, N. margin of area,
I N. 57° E., 40° W. ; near head of Mianus R., /. N. 84° E., 60° N., varying to N.
48° W., 40° W. ; just to E., 300 yds. S. of road, /. N. 67° E., 55° W., and K side
of same low hill, consists of granulyte (cream-colored orthoclase and a few garnets),
N. 57° E., 65°-70° W.; 300 yds. E. of last, after passing the granulyte, morei;
limestone valley here fronted to N. by a high, nearly E. and W., precipice of
bedded gn., strike of gn. N. 62° E., 25° W. If mile E. of Bedford village, gn.
N. 3° W. to N. 17° E., 65°-70° W.; 2 miles to 2£ E. of Bedford village, thin to
thick gn. N. 42° N., 45°-50° W.

Area 25. — East of N.E. end of area, m. gn. or m. sch. N. 21° E., 50° W.; |
mile S.W., thick-bedded gn., porphyritic with some thin micaceous layers, feldspar
crystals |-1£ inches long, N. 24° E., 55° W., changes to reddish granite ; I. out-
crops to W., but bedding not distinct ; 1 mile S.W. of last, thin gn., K". 24° E.,
var. to N. 42° E., dip W. ; £ mile W. of W. end of area, thick-bedded gn. N. 57°
E., 35°-40° W.

Area 26.-1* mile S.W. of Ridgefield, m. sch. N. 37° E., dip 38° W.; 1 mile
farther S.W., /. N. 3° W. to N. 14° E., 55° W.; 1 mile S.W. of last, and i mile
W. of /., gn. N. 25° E. (average), dip 45°-60° W., again N. 18° E., 55° W.— Near S.
end of area, E. of Pound Ridge, W. of lower pond of Trinity Lake, I. N. 25°-40°
E., 50° W., adjoining I. to E., hbl. sch. N. 22° E., 55° W.; then E. of this, I. N.
12° -22° E., 50°-55° W., and next, rusting m. sch. On E. border of valley whitish
gn. (the mica white), N. 47° E., 45° W. ; just east of this, white granulyte (some
triclinic feldspar in it), dip W. — Near Pound Ridge, W. of I. area, gn. (thin to thick-
bedded) N. 47°-50°-37° E., 45°-50° W.; f mile to S., rusting m. gn., N. 27° E.,
60° W.

Area 27.— At Cruger's, on R.R., S. of station, N. end of cut, I N. 53°-57° K.,
dip 60° W. ; S. end of cut, N. 81° W., 40°-45° E. (or N.), much jointed; N. side
of cove S. of l, 225 yds. from R.R., l. N. 28' W., 40° E., beyond up the cove, I.
N. 53°-63° W., 60° K., and near eastern limit of limestone, /. N. 68°-75° W.,
70°-80° E. ; gneiss along road near by and adjoining the bridge N. 68°-78° E.,
65°-80° E.; up slope to north, m. sch. and gn., N. 82°-72° E., 70°-^0° W. (or N.)
and /. N. 78°-85° W., 70° E. (or N.); on shore, S. of this cove, gray and flesh-
colored gn. N. 14° E., 68°-80° W. ; in eastern part of I. area, /. N. 73°-78c W.f and
m. sch. adjoining about east and west, dip of both 75°-80° N.. greatly contorted
so that in most parts strike undeterminable. West of R.R. station, on shore, I. and
m. sch., N. 66°-80° E., 70°-85° W. (or N.); i mile W. of station, m. sch. N. 87°
E., and farther W., N. 80° W.

Area 28. — f mile N.E. of Verplanck Point W. of Broadway, 2. and included
m. sch. N. 15-20° E.; arenaceous or gneissic m. sch., 300 yds. from upper end
of Broadway (at d) N. 7 " E. to N. 23° W., 70° E.; I. at/, (on road 550 yds. W. of
Church corner) N. 60° W., 70°-80° E. ; some arenaceous ^.adjoining it, but
outcrop small and poor.

Area 29. — Tn Canopus Hollow, at mouth of Sprout Brook, near Iron Works, /.
N. 470-54' E., 60-70° E.; adjoining quartzyte N. 47°-55° E., 60° E.; schistose
band in quartzvto to south half way from the point to R.R. station, N. 47°-55°,
60°-75° K.

400 yds. S. of Annsville, on river, I. contorted, very fine-grained, slightly crys-
talline, N. 20°-44°'E., N. 42° E. average, 55°-60° E.; E. side of Sprout Brook,
near junction with Peekskill Creek, hydromica sch. N. 24°-31° E., 60° E. ; up
brook, at quarry. I. N. 32° K. to N. 8° W., 70° E.; above crossing of brook by
road, /. N. 42°-52° E., dip W., and nearly 150 yds. N.E. of road, I twisted in with
?/»., N. 8^ W. to N. 62° E., and a gneissiod quartzyte in the N. side of the hill,
N. 07 E. (this is where the T-symbols make an X on the map, and here N. side
of valley is bounded by the Highland Archaean about 100 rods distant); just S. of

J. D. Dana — Geology of Westchester County, N. Y. 335

boundary of county, E. of brook, I. N. 27°-32° E., 65°-70° E. ; just N. of boundary
in Putnam Co.; valley i mile wide, I. N. 27°-29° K., 70°-75° W.; farther N.E.,
under bridge (at Continental Village), I. (with beds of quartzyte) N. 45° E., partly
graphitic; bordering /. on W., slate N. 53° E., 70° E. ; £ mile N.E. of last, por-
phyritic granite (Archaean?) ; W. of carriage road, the valley nearly £ mile wide;
£ mile N.E. of last, rusting m. sch., N. 17° E., 80° W. to 90°; porph. granite
lies northwest of schist; here, on W. side of valley. /. N. 37°-44° E., dip W.; /.
in valley nearly 100 yds. S. of Croft's mine, and thin m. gn. west of road; 400
yds. N. of the mine, I. impure, N. 25° E., 80° W., same m. gn. W. of road;
in the valley (Canopus Hollow), between N. end of Solpue Pond and S. end
of Oscawana Lake, I. N. 53° E., dip E., involved with quartzytic gneiss ; valley of 7.
here ^ mile wide, I. ends near where the road of the vslley crosses the stream here
called Canopus Creek.

Area 30 A. — See Am. Journ. Sci., xx, 214, 1880, for angles. Tn Crom Pond
street N. of Academy Grounds, Peekskill, thin m. sch. N. 85° E., 75°-80°S.;
a small show of limestone on the road side, but it may be a loose block.

Area 30.— In Peekskill Hollow at the most N.E. outcrop of I. (ib., p. 369), I. N.
41°-48° E., 60° W.; also a quarry of quartzyte slabs; 100 to 150 ds. of I. ; at
Adams Corners, /. white and bluish, very fine grain, N. 47° E., 45°-50° E, but
varying much; just below Oregon, I. N. 32° E., with hydromica slate (looking like
argillyte) along side and conformable. N. outcrop of I. seen in Peekskill creek
valley south of this point.

Area 31.— l^ mile S. of E. of area, .hard contorted gn., N. 83° W. to N. 82° E.,
80° N.; | mile E. of Muscoot River, I. nearly E. and W., dip 90°; E. of W.
boundary of Somers, near Bennett's, I N. 33° W., N. 8° W., N. 48° W., con-
torted, dip E. ; N. of area, gn., N. 80° E., 80° K. to 90° ; £ mile E. of HaUock's
mills, /. N. 54° E., 62°-80° E. to 90°.

Area 32. — f mile to ± mile E. of area, m. gn. N. 72° E. to N. 88° W., 65° N.
to 90°; E. end of area, I. N. 74° E., dip 70° N. ; near W. end, I. N. 72° E. ; W,
of area, near R.R., hard gn. N. 72° E.

Area 34a.— S. part of area, /. nearly E. and W. to N. 57° E., dip N. ; N.W.
part, I. N. 78° TV. to E. and W., 70° W. ; gn. just N. aud £ mile S., conformable.
At Golden Bridge, 300 yds. W. of station, m. sch., N. 73° W. to N. 62° E., large
granite vein in it; same, rn. sch., \ mile N. of Golden Bridge.

Area 346.— Area W. of L. Waccabuc; I. seen in bowlders, but not in place.

Area 35.— At neck, E. end of lake, N. of brook, I. N. 62°-67° E. (var. to N.
57° E), 50° N. ; just N., m. gn. N. 62° E., 80° N. ; S. of /. and end of lake, m. gn.,
N. 73° W., dip N. ; nearly 1 mile E., thin gn., N. 58° E. ; but farther west, S. of
lake, gn. granitoid.

Area 36. — To E. at Connecticut boundary, where the valley is very narrow
(and the I. may be for a while interrupted), gn. N. 60°-62° E., 90° to 80° W.; $
mile E. of N. Salem, /. N. 68° W. to N. 82° E., dip N., cryst. very coarse; £ mile
S.W. of N. Salem, /. N. 67° E., 50°-60° W.; Salem Center, W. of cross roads,
hard gn. (in the I. area) N. 57° E.; 300 yds. W. of S. Center, I. N. 77° E., 57°
W. ; 1 mile W. of Salem Center, near N. margin of I., gn. N. 69° W. ; S. of last, I. N.
78° W., 90° ; 400 yds. to W., 1. N. 66°-73° W., £ mile ; i mile W. of Decker's, I. N.
74°-88° W., dip 90°, and \ mile W. of Decker's, I N. 88° W., 75° N. ; N. of I.
area, N. 88° E., 60° N. ; near limekiln W. of Mrs. Bailey's, I. N. 87° E. ; and just
N., gn. same dip 80° N. ; $ mile W., valley narrows, and I. ends.

Area 37. — S. of E. end, thin gn. N. 88° W., 70° N. ; no I. seen where examined,
but features those of a I. valley. About Peach Lake, mostly hard whitish to gray
gneiss, some slightly reddish; at south end strike N. 58°-73° W., dip 55°-60° E.
At Croton Falls, near R.R. station, black micaceous rock (hblc.) N. 73° W.. dip to
north.

22a

AM. JOUR. SCI., Vol. XXI

THE

AMEEICAN JOURNAL OF SCIENCE.

[THIRD SERIES.]

#♦♦

Art. XLV. — Jurassic Birds and their Allies; by Professor

O. C. Marsh.

[Read before Section D., British Association for the Advancement of Science, at

York, Sept. 2d, 1881.]

About twenty years ago, two fossil animals of great interest
were found in the lithographic slates of Bavaria. One was
the skeleton of Archceopteryx, now in the British Museum, and
the other was the Compsognathus preserved in the Royal Mu-
seum at Munich. A single feather, to which the name Archce-
opteryx was first applied by Von Meyer, had previously been
discovered at the same locality. More recently, another skele-
ton has been brought to light in the same beds, and is now in
the Museum of Berlin. These three specimens of Archceopteryx
are the only remains of this genus known, while of Compsogna-
thus the original skeleton is, up to the present time, the only
representative.

When these two animals were first discovered, they were
both considered to be reptiles by Wagner, who described
Compsognathus, and this view has been held by various authors
down to the present time. The best authorities, however, now
agree with Owen that Archceopteryx is a bird, and that Compso-
gnathus, as Gegenbaur and Huxley have shown, isaDinosaurian
reptile.

Having been engaged for several years in the investigation
of American Mesozoic birds, it became important for me to
study the European forms, and I have recently examined with

Am. Jour. Sol— Third Series, Vol. XXII, No. 131.— November, 1881.

338 0. C. Marsh — Jurassic Birds and their Allies.

some care the three known specimens of Archawpleryx. I have
also studied in the Continental Museums various fossil reptiles,
including Compsognathus, which promised to throw light on
the early forms of birds.

During my investigation of Arch&opteryx, I observed several
characters of importance not previously determined, and I have
thought it might be appropriate to present them here. The
more important of these characters are as follows : —

1. The presence of true teeth, in position, in the skull.

2. Vertebrae biconcave.

3. A well-ossified, broad sternum.

4. Three digits only in the manus, all with. claws.

5. Pelvic bones separate.

6. The distal end of fibula in front of tibia.

7. Metatarsals separate, or imperfectly united.

These characters, taken in connection with the free metacar-
pals, and long tail, previously described, show clearly that we
have in Archasopteryx a most remarkable form, which, if a bird,
as I believe, is certainly the most reptilian of birds.

If now we examine these various characters in detail, their
importance will be apparent

The teeth actually in position in the skull appear to be in
the premaxillary, as they are below or in front of the nasal
aperture. The form of the teeth, both crown and root, is very
similar to the teeth of Hesperornis. The fact that some teeth
are scattered about near the jaw would suggest that they were
implanted in a groove. No teeth are known from the lower
jaw, but they were probably present

The presacral vertebrae are all, or nearly all, biconcave,
resembling those of Ichihyornis in general form, but without
the large lateral foramina. There appear to be twenty-one
presacral vertebrae, and the same, or nearly the same, number
of caudals. The sacral vertebrae are fewer in number than in
any known bird, those united together not exceeding five, and
probably less.

The scapular arch strongly resembles that of modern birds.
The articulation of the scapula and coracoid, and the latter
with the sternum is characteristic; and the furculum is dis-
tinctly avian. The sternum is a single broad plate, well
ossified. It probably supported a keel, but this is not exposed
in the known specimens.

In the wing itself the main interest centers in the manus and
its free metacarpals. In form and position these three bones
are just what may be seen in some young birds of to-day.
This is an important point, as it has been claimed that the
hand of Archaeopteryx is not at all avian, but reptilian. The

0. 0. Marsh — Jurassic Birds and their A Hies. 339

bones of the reptile are indeed there, but they have already
received the stamp of the bird.

One of the most interesting points determined during my
investigation of Archceopteryx was the separate condition of the
pelvic bones. In all other known adult birds, recent and ex-
tinct, the three pelvic elements, ilium, ischium and pubis, are
firmly anchylosed. In young birds these bones are separate,
and in all known Dinosaurian reptiles they are also distinct.
This point may perhaps be made clearer by referring to the
two diagrams before you, which I owe to the kindness of my
friend Dr. Woodwardj of the British Museum, who also gave
me excellent facilities for examining the Archceopteryx under
his care. In the first diagram we have represented the pelvis
of an American Jurassic Dinosaur allied to Iguanodon, and
here the pelvic bones are distinct. The second diagram is an
enlarged view of the pelvis of .the Archceopteryx in the British
Museum, and here too the ilium is seen separate from the
ischium and pubis.

In birds the fibula is usually incomplete below, but it may
be coossified with the side of the tibia. In the typical Dino-
saurs, Iguanodon, for example, the fibula at its distal end stands
in front of the tibia, and this is exactly its position in Archce-
opteryx, an interesting point not before seen in birds.

The metatarsal bones of Archceopteryx show, on the outer
face at least, deep grooves between the three elements, which
imply that the latter are distinct, or unite late together. The
free metacarpal and separate pelvic bones would also suggest
distinct metatarsals, although they naturally would be placed
closely together, so as to appear connate.

Among other points of interest in Archceopteryx may be men-
tioned the brain-cast, which shows that the brain, although
comparatively small, was like that of a bird, and not that of a
Dinosaurian reptile. It resembles in form the brain-cast of
Laopteryx, an American Jurassic bird, which I have recently
described. The brain of both these birds appears to have been
of a somewhat higher grade than that of Hesperornis, but this
may have been due to the fact that the latter was an aquatic
form, while the Jurassic species were land birds.

As the Dinosauria are now generally considered the nearest
allies to birds, it was interesting to find in those investigated
many points of resemblance to the latter class. Gompsognathus^
for example, shows in its extremities a striking similarity to
Archceopteryx. The three clawed digits of the manus correspond
closely with those of that genus; although the bones are of
different proportions. The hind feet also have essentially the
same structure in both. The vertebrae, however, and the pelvic
bones of Compsognathus differ materially from those of Archce-

340 0. C. Marsh — Jurassic Birds and their Allies.

opteryx, and the two forms are in reality widely separated.
While examining the Compsognathus skeleton, I detected in the
abdominal cavity the remains of a small reptile which had not
been previously observed. The size and position of this in-
closed skeleton would imply that it was a foetus ; but it may
possibly have been the young of the same species, or an allied
form, that had been swallowed No similar instance is known
among the Dinosaurs.

A point of resemblance of some importance between birds
and Dinosaurs is the clavicle. All biros have those bones, bnt
they have been considered wanting in Dinosaurs. Two speci-
mens of Iguanodon, in the British Museum, however, show that
these elements of the pectoral arch were present in that genus,
and in a diagram before you one of these bones is represented.
Some other Dinosauria possess clavicles, but in several families
of this subclass, as T regard it, they appear to be wanting.

The nearest approach to birds now known would seem to be
in the very small Dinosaurs from the American Jurassic. In
some of these, the separate bones of the skeleton cannot be
distinguished with certainty from those of Jurassic birds, if the
skull is wanting, and even in this part the resemblance is strik-
ing. Some of these diminutive Dinosaurs were perhaps arbo-
real in habit, and the difference between them and the birds
that lived with them may have been at first mainly one of
feathers, as I have shown in my Memoir on the Odontornithes,
published during the past year.

It is an interesting fact that all the Jurassic birds known,
both from Europe and America, are land birds, while all from
the Cretaceous are aquatic forms. The four oldest known birds,
moreover, differ more widely from each other than do any two
recent birds. These facts show that we may hope for most
important discoveries in the future, especially from the Triassic
which has as yet furnished no authentic trace of birds. For
the primitive forms of this class we must evidently look to the
Paleozoic.

J. M. Schaeberle— Aurora of September 12-13, 1881. 341

Art. XL VI. — On the Remarkable Aurora of September 12-13,

1881 ; by J. M. Schaeberle.

The night of Sept. 12-13, 1881, witnessed one of the grand-
est displays of aurora ever seen in this latitude. Beginning
soon after sunset and lasting until the approach of day, the
various phenomena which presented themselves during this
time are deserving of being placed on permanent record.

The following are some of the notes taken during the night :

fh 30m — Ann Arbor, mean time. A grand continuous arch
seen spanning the northeastern sky, beginning in the horizon at
IS. 1° N., aud endiug N. 45° W. ; altitude of highest point of
arch 30° ; breadth, 5° (close resemblance to cirrus clouds). A
second arch, enclosed by the first and 10° from it, quite bright.
Space between the arches clear as any part of the sky.

7h 35m. At the eastern extremity of the large arc are streamers
inclined 70° to the horizon.

1h 37m. Four bright streamers in the east, 15° long, l£° wide,
and 2° from each other.

7h 41m. Bright streamer, 40° long, l£° broad, E. 10° N.
Bright auroral light in northern horizon ; most intense, N. 40° E.

ft 42m. Broad sheet of streamers iu the east ; horizontal mo-
tion from east to west, very marked; rate, 1° in 8 seconds of
time. Large arch has disappeared.

7h 50m. Dark segment ; greatest altitude 3°, at N. 20° E.
a Aurigse seen through the same with undiminished luster.

7h 56m. Streamers 5° long between N. 30° W., and N. 70° E.
It is very evident that the dark segment is nothing but the clear
sky, for occasionally a streamer starts from the very horizon and
in moving west the dark space seems to offer uo resistance.

8h 2m. Streamers 15° long; a detached one in Cassiopeia, 45°
from the horizon, seen moving westward at the rate of 1° in 3
seconds.

8h 5m. Dark segment 5° high ; streamers form one continuous
sheet of light. In the northeast streamers start 2° from horizon
and in their motion westward plough through the dark space.

8h, 12m-20ra. Bright arch from N. 30° W. to N. 00° E. ;
greatest elevation, 10° ; occasional streamers, from 3° to 5° in
length, shooting from it. Electric lightning in the east.

8* 31m. Streamers in the north 15° long; dark segment 6°
high, but very irregular in outline.

8h 33m. Continuous sheet of light iu N.N.E. ; no arch.

llh 45m. Up to the present time only the auroral twilight
could be seen. Moon about three hours high ; signs of return-
ing activity; dark segment 7° high.

llh 53ra. Bright streamer 40° long, K 10° E.

llh 54m. Three arches; whole northern sky covered with
streamers 45° in length.

llh 56m. Streamers of a reddish tinge, 55° in length; arch
broken near the north point ; western portion wanting.

342 J. M. Schaeberle— Aurora of September 12-13, 1881.

12h"0in. Arch 16° high, symmetrical with respect to the meri-
dian. Irregular black patches distributed throughout the space
enclosed by the arch ; sty in the northwest has a reddish tinge.
Motiou from east to west, 1° in 3 seconds.

12h 10m. Waves toward the zenith very violent ; streamers
50° long.

12b 13m-l7m. Whole northern sky up to 45° altitude, in great
commotion ; streamers 60° long.

12b 30m-60m. Streamers from the east and west points of
horizon meet south of the zenith, within the square of Pegasus,
several parallel spans formed and broken at short intervals.

13h. Streamers extend 15° southeast of the point of conver-
gence, which is now near a Andromeda?.

13h 20m. Arch from east to west, altitude 25°; vigorous ac-
tion of auroral waves.

13h 30m. The crossing of the streamers in the zenith gives the
appearance of a zigzag motion.

13h 30m. Point of convergence near 6 Andromeda?.

13h 41m. Remarkable streamer E. 30° N., beginning in the
horizon and for a distance of 8° making an angle of only 30° with
it, then suddenly changing its direction to parallelism with the
other streamers each side of it which are inclined 75° to the
horizon.

13b 55m. Sudden abatement of vigorous action; looks as
though the display was coming to a close.

14* 2m. Two arches formed, one in the N.E. the other in the
N.N. W., joining each other in the horizon 15° east of north point

Observations resumed at 15h 45m. The view now presented to
the observer baffles all description. The whole northern sky
from N. 55 W., to N. 55 E. and from the horizon to 60° altitude
is one mass of moving fire. The auroral waves succeed each
other with great rapidity. Each wave extends throughout the
entire width of the aurora, and the flashes toward the zenith are
in the form of segments of small circles or zones parallel to the
horizon. In the northeast the phenomenon known as the merry
dancers is very beautiful. A little to the west of north sudden
outbursts of light, similar to sheet lightning and having the
form of cumulus clouds, instantly appear and disappear at short
intervals.

This description can give but a faint idea of the appearance
of the aurora at the close of my observations. A though the
moon was still two days from last quarter the phenomena were
seen with a vividness truly remarkable. On the following
evening the auroral twilight was quite bright until the moon
came up. An arch was formed and broken several times.
About nine o'clock the northern sky had the appearance of
being covered with faint streamers 40° loug. Later the aurora
gradually died out, and by eleven o'clock no trace of it could
be seen.

Sir John Lubbock's Address. 343

Art. XL VII. — Address of Sir John Lubbock, President of the

British Association at York.

[Continued from page 289.]

* * In Astronomy, the discovery in 1845 of the planet Nep-
tune, made independently and almost simultaneously by Adams
and by Le Verrier, was certainly one of the greatest triumphs
of mathematical genius. Of the minor planets four only were
known in 1881, whilst the number now on the roll amounts to
220. Many astronomers believe in the existence of an intra-
mercurial planet or planets, but this is still an open question.
The Solar System has also been enriched by the discovery of
an inner ring to Saturn, of satellites to Mars, and of additional
satellites to Saturn, Uranus and Neptune.

The most unexpected progress, however, in our astronomical
knowledge during the past half-century has been due to spec-
trum analysis.

The dark lines in the spectrum were first seen by Wollaston,
who noticed a few of them ; but they were independently dis-
covered by Fraunhofer, after whom they are justly named, and
who, in 1814, mapped no fewer than 576. The first steps in
" spectrum analysis," properly so called, were made by Sir J.
Herschel, Fox Talbot, and by Wheatstone, in a paper read be-
fore this Association in 1835. The latter showed that the spec-
trum emitted by the incandescent vapor of metals was formed
of bright lines, and that these lines, while, as he then supposed,
constant for each metal, differed for different metals. " We have
here," he said, " a mode of discriminating metallic bodies more
readily than that of chemical examination, and which may here-
after be employed for useful purposes/' Nay, not only can
bodies thus be more readily discriminated, but, as we now know,
the presence of extremely minute portions can be detected, the
gooioootn Part °f a grain being in some cases easily perceptible.

It is also easy to see that the presence of any new simple sub-
stance might be detected, and in this manner already several
new elements have been discovered.

But spectrum analysis has led to even grander and more un-
expected triumphs. Fraunhofer himself noticed the coincidence
between the double dark line D of the solar spectrum and a
double line which he observed in the spectra of ordinary flames,
while Stokes pointed out to Sir W. Thompson, who taught it
in his lectures, that in both cases these lines were due to the
presence of sodium. To Kirchhoff and Bunsen, however, is due
the independent conception and the credit of having first sys-
tematically investigated the relation which exists between
Fraunhofer's lines and the bright lines in the spectra of incan-

344 Sir John Lubbock's Address.

descent metals. In order to get some fixed measure by which
they might determine and record the lines characterizing any
given substance, it occurred to them that they might use for
comparison the spectrum of the sun. They accordingly ar-
ranged their spectroscope so that one-half of the slit was lighted
by the sun, and the other by the luminous gases they pro-
posed to examine. It immediately struck them that the bright
lines in the one corresponded with the dark lines in the other—
the bright line of sodium, for instance, with the line or rather
lines D in the sun's spectrum. The conclusion was obviooa
There was sodium in the sun ! It must indeed have been a
glorious moment when that thought flashed across them, and
even by itself well worth all their labor.

But why is the bright line of a sodium flame represented by
a black one in the spectrum of the sun ? To Angstrom is due
the theory that a vapor of gas can absorb luminous rays
of the same refrangibility only which it emits when highly
heated; while Balfour Stewart independently discovered the
same law with reference to radiant heat.

This is the basis of KirchhofF s theory of the origin of Fraun-
hofer's lines. In the atmosphere of the sun the vapors of
various metals are present, each of which would give its char-
acteristic lines, but within this atmospheric envelope is the still
more intensely heated nucleus of the sun. which emits a bril-
liant continuous spectrum, containing rays of all degrees of re-
frangibility. When the light of this intensely heated nucleus
is transmitted through the surrounding atmosphere, the bright
lines which would be produced by this atmosphere are seen as
dark ones.

Kirchhoff and Bunsen thus proved the existence in the sun of
hydrogen, sodium, magnesium, calcium, iron, nickel, chromium,
manganese, titanium and cobalt; since which Angstrom, Thalen
and Lockyer have considerably increased the list.

But it is not merely the chemistry of the heavenly bodies on
which light is thrown by the spectroscope; their physical
structure and evolutional history are also illuminated by this
wonderful instrument of research.

It used to be supposed that the sun was a dark body envel-
oped in a luminous atmosphere. The reverse now appears to
be the truth. The body of the sun, or photosphere, is intensely
brilliant ; round it lies the solar atmosphere of comparatively
cool gases, which cause the dark lines in the spectrum ; thirdly,
a chromosphere, — a sphere principally of hydrogen, jets of
which are said sometimes to reach to a height of 100,000 miles
or more, into the outer coating or corona, the nature of which
is still very doubtful.

Formerly the red flames which represent the higher regions

Sir John Lubbock's Address. 345

of the chromosphere could be seen only on the rare occasions
of a total solar eclipse. Janssen and Lockyer, by the applica-
tion of the spectroscope, have enabled us to study this region
of the sun at all times.

It is, moreover, obvious that the powerful engine of investi-
gation afforded us by the spectroscope is by no means confined
to the substances which form part of our system. The incan-
descent body can thus be examined, no matter how great its
distance, so long only as the light is strong enaugh. That this
method was theoretically applied to the light of the stars was
indeed obvious, but the practical difficulties were very great
Sirius, the brightest of all, is, in round numbers, a hundred
millions of millions of miles from us ; and, though as big as
sixty of our suns, his light when it reaches us after a journey
of sixteen years, is at most one two-thousand-millionth part as
bright. Nevertheless as long ago as 1815 Fraunhofer recog-
nized the fixed lines in the light of four of the stars, and in 1863
Miller and Huggins in our own country, and Kutherfurd in
America, succeeded in determining the dark lines in the spec-
trum of some of the brighter stars, thus showing that these
beautiful and mysterious lights contain many of the material
substances with which we are familiar. In Aldebaran, for in-
stance, we may infer the presence of hydrogen, sodium, magne-
sium, iron, calcium, tellurium, antimony, bismuth, and mercury ;
some of which are not yet known to occur in the sun. As
might have been expected the composition of the stars is not
uniform, and it would appear that they may be arranged in a
few well marked classes, indicating differences of temperature,
or in other words of age. Some recent photographic spectra
of stars obtained by Huggins go very far to justify this view.

Thus we can make the stars teach us their own composition
with light which started from its source before we were born —
light older than our Association itself.

Until 1864, the true nature of the unresolved nebulae was a
matter of doubt. In that year, however, Huggins turned his
spectroscope on to a nebula, and made the unexpected discovery
that the spectra of some of these bodies are discontinuous — that
is to say, consist of bright lines only, indicating that "in place
of an incandescent solid or liquid body we must probably
regard these objects, or at least their photo-surfaces, as enor^
mous masses of luminous gas or vapor. For it is from matter
in a gaseous state only that such light as that of the nebulaa is
known to be emitted." So far as observation has yet gone,
nebulae may be divided into two classes: some giving a contin-
uous spectrum, others one consisting of bright lines. These
latter all appear to give essentially the same spectrum, consist-
ing of a few bright lines. Two of them, in Mr. Huggins's

346 Sir John Lubbock's Address.

opinion, indicate the presence of hydrogen : one of them agrees
in position with a line characteristic of nitrogen.

But spectrum analysis has even more than this to tell us.
The old methods of observation could determine the move-
ments of the stars so far only as they were transverse to us;
they afforded no means of measuring motion either directly
towards or away from us. Now Doppler suggested in 1841
that the colors of the stars would assist us in this respect, be-
cause they would be affected by their motion to and from the
earth, just as a steam-whistle is raised or lowered as it ap-
proaches or recedes from us. Everyone has observed that if a
train whistles as it passes us, the sound appears to alter at the
moment the engine goes by. This arises, of course, not from
any change in the whistle itself, but because the number of
vibrations which reach the ear in a given time are increased by
the speed of the train as it approaches, and diminished as it
recedes. So, like the sound, the color would be affected by
such a movement ; but Doppler's method was practically inap- t
plicable, because the amount of effect on the color would be
utterly insensible ; and even if it were otherwise the method
could not be applied, because, as we did not know the true
color of the stars, we have no datum line by which to measure.

A change of refrangibility of light, however, does occur in
consequence of relative motion, and Huggins successfully
applied the spectroscope to solve the problem. He took in the
first place the spectrum of Sirius, and chose a line known as F,
which is due to hydrogen. Now, if Sirius was motionless, or
rather if it retained a constant distance from the earth, the line
P would occupy exactly the same position in the spectrum of
Sirius, as in that of the sun. On the contrary if Sirius were
approaching or receding from us, this line would be slightly
shifted either toward the blue or red end of the spectrum.
He found that the line had moved very slightly toward the
red, indicating that the distance between us and Sirius is
increasing at the rate of about twenty miles a second. So also
Betelgeux, Kigel, Castor and Regulus are increasing their dis-
tance ; whfle, on the contrary, that of others, as for instance of
Vega, Arcturus and Pollux, is diminishing. The results ob-
tained by Huggins on about twenty stars have since been con-
firmed and extended by Mr. Christie, now Astronomer Royal,
in succession to Sir G. Airy, who has long occupied the post
with so much honor to himself and advantage to science.

To examine the spectrum of a shooting star would seem even
more difficult ; yet Alexander Herschel has succeeded in doing
so, and finds that their nuclei are incandescent solid bodies:
he has recognized the lines of potassium, sodium, lithium and
other substances, and considers that the shooting stars are

Si/r John Lubbock's Address. 347

bodies similar in character and composition to the stony masses
which sometimes reach the earth as aerolites.

Some light has also been thrown upon those mysterious visi-
tants, the comets. The researches of Prof. Newton on the
periods of meteoroids led to the remarkable discovery by
Schiaparelli of the identity of the orbits of some meteor-swarms
with those of some comets. The similarity of orbits is too
striking to be the result of chance, and shows a true cosmical
relation between the bodies. Comets, in fact, are in some cases
at any rate groups of meteoric stones. Prom the spectra of the
small comets of 1866 and 1868, Huggins showed that part of
their light is emitted by themselves, and reveals the presence of
carbon in some form. A photographic spectrum of the comet
recently visible, obtained by the same observer, is considered
by him to prove that nitrogen, probably in combination with
carbon, is also present.

No element has yet been found in any meteorite, which was
not previously known as existing in the earth, but the phenom-
ena which they exhibit indicate that they must have been
formed under conditions very different from those which pre-
vail on the earths surface. I may mention, for instance, the
peculiar form of crystallized silica, called by Maskelyne, Asma-
nite ; and the whole class of meteorites, consisting of iron gener-
ally alloyed with nickel, which Daubree terms holosiderites.
The interesting discovery, however, by Nordenskiold, in 1870,
at Ovifak, of a number of blocks of iron alloved with nickel
and cobalt, in connection with basalts containing disseminated
iron, has, in the words of Judd, " afforded a very important link,
placing the terrestrial and extra-terrestrial rocks in closer rela-
tions with one another."

We have as yet no sufficient evidence to justify a conclusion
as to whether any substances exist in the heavenly bodies
which do not occur in our earth, thought there are many lines
which cannot yet be satisfactorily referred to any terrestrial ele-
ment. On the other hand, some substances which occur on our
earth have not yet been detected in the sun's atmosphere.

Such discoveries as these seemed, not long ago, entirely be-
yond our hopes. M. Comte, indeed, in his " Cours de Philoso-
phic Positive," as recently as 1842, laid it down as an axiom re-
garding the heavenly bodies, that "Nous concevons la possibility
de determiner leurs formes, leurs distances, leurs grandeurs et
leurs mouvements, tandis que nous ne saurions jamais etudier
par aucun moyen leur composition chimique ou leur structure
mineral ogique." Yet within a few years what he supposed to
be impossible has been actually accomplished, showing how
unsafe it is to limit the possibilities of science.

It is hardly necessary to point out that, while the spectrum

348 Sir John Lubbock's Address.

has taught us so much, we have still even more to learn. Why
should some substances give few, and others many, lines?
Why should the same substance give different lines at different
temperatures? What are the relations between the lines and
the physical or chemical properties.

We may certainly look for much new knowledge of the
hidden actions of atoms and molecules from future researches
with the spectroscope. It may even, perhaps, teach us to
modify our views of the so-called simple substances. Prout
long ago, struck by the remarkable fact that nearly all atomic
weights are simple multiples of the atomic weight of hydrogen,
suggested that hydrogen must be the primordial substance.
Brodie's researches also naturally fell in with the supposition
that the so-called simple substances are in reality complex,
and that their constituents occur separately in the hottest
regions of the solar atmosphere. Lockyer considers that his
researches lend great probability to this view. The whole sub-
ject is one of intense interest, and we may rejoice that it is
occupying the attention, not only of such men as Abney,
Dewar, Hartley, Liveing, Roscoe and Shuster in our own
country, but also of many foreign observers.

When geology so greatly extended our ideas of past time,
the continued heat of the sun became a question of greater
interest than ever. Helmholtz has shown that, while adopting
the nebular hypothesis, we need not assume that the nebulous
matter was originally incandescent; but that its present high
temperature may be, and probably is, mainly due to gravita-
tion between its parts. It follows that the potential energy
of the sun is far from exhausted, and that with continued
shrinking it will continue to give out light and heat, with little,
if any, diminution for several millions of years.

Like the sands of the sea, the stars of heaven have ever been
used as effective symbols of number, and the improvements in
our methods of observation have added fresh force to our
original impressions. We now know that our earth is but a
fraction of one out of at least 75,000,000 worlds.

But this is not all. In addition to the luminous heavenly
bodies, we cannot doubt that there are countless others, invisi-
ble to us from their greater distance, smaller size, or feebler
light; indeed we know that there are many dark bodies which
now emit no light or comparatively little. Thus in the case of
Procyon, the existence of an invisible body is proved by the
movement of the visible star. Again I may refer to the curi-
ous phenomena presented by Algol, a bright star in the head
of Medusa. This star shines without change for two days and
thirteen hours ; then, in three hours and a half, dwindles from
a star of the second to one of the fourth magnitude ; and

Sir John Lubbock's Address. 349

then, in another three and a half hours, reassumes its original
brilliancy. These changes seem certainly to indicate the pres-
ence of an opaque body, which intercepts at regular intervals
a part of the light emitted by Algol.

Thus the floor of heaven is not only "thick inlaid with
patines of bright gold," but studded also with extinct stars;
once probably as brilliant as our own sun, but now dead and
cold, as Helmholtz tells us that our sun itself will be, some sev-
enteen millions of years hence.

The connection of Astronomy with the history of our planet
has been a subject of speculation and research during a great
part of the half century of our existence. Sir Charles Lyell
devoted some of the opening* chapters of his great work to the
subject Haughton has brought his very original powers to
bear on the subject of secular changes in climate, and Croll's
contributions to the same subject are of great interest Last,
but not least, I must not omit to make mention of the series
of massive memoirs (I arn happy to say not yet nearly ter-
minated) by George Darwin on tidal friction, and the influ-
ence of tidal action on the evolution of the solar system.

I may perhaps just mention, as regards telescopes, that the
largest reflector in 1830 was Sir W. Herschel's of 4 ft, the
largest at present being Lord Rosse's of 6 ft. ; as regards refrac-
tors the largest then had a diameter of 11J in., while your
fellow townsman Cooke carried the size to 25 in., and Mr.
Qrubb, of Dublin, has just successfully completed one of 27
in. for the Observatory of Vienna. It is remarkable that the
two largest telescopes in the world should both be Irish.

The general result of astronomical researches has been thus
eloquently summed up by Proctor: — "The sidereal system is
altogether more complicated and more varied in structure than
has hitherto been supposed ; in the same region of the stellar
depths coexist stars of many orders of real magnitude; all
orders of nebulae, gaseous or stellar planetary, ring-formed,
elliptical, and spiral, exist within the limits of the galaxy; and
lastly, the whole system is alive with movements, the laws of
which may one day be recognized, though at present they
appear too complex to be understood."

We can, I think, scarcely claim the establishment of the
undulatory theory of light as falling within the last fifty years;
for though Brewster, in his u Report on Optics," published in
our first volume, treats the question as open, and expresses
himself still unconvinced, he was, I believe, almost alone in his
preference for the emission theory. The phenomena of inter-
ference, in fact, left hardly any — if any — room for doubt,
and the subject was finally set at rest by Foucault's celebrated

350 Sir John Lubbock's Address.

experiments in 1850. According to the undulatory theory the
velocity of light ought to be greater in air than in water,
while if the emission theory were correct the reverse would
be the case. The velocity of light — 186,000 miles in a sec-
ond— is, however, so great that, to determine its rate in air,
as compared with that in water, might seem almost hopeless.
The velocity in air was, nevertheless, determined by Fizeau in
1849, by means of a rapidly revolving wheel. In the follow-
ing year Foucault, by means of a revolving mirror, demon-
strated that the velocity of light is greater -in air than in
water — thus completing the evidence in favor of the undula-
torj theory of light.

The idea is now gaining ground, that, as maintained by
Clerk-Maxwell, light itself is an electro-magnetic disturbance,
the luminiferous ether being the vehicle of both light and
electricity.

Wiinsch, as long ago as 1792, had clearly shown that the
three primary colors were red, green, and violet ; but his re-
sults attracted little notice, and the general view used to be
that there were seven principal colors — red, orange, yellow,
green, blue, indigo and violet ; four of which — namely
orange, green, indigo and violet — were considered to rise
from mixtures of the other three. Red, yellow and blue were
therefore called the primary colors, and it was supposed that
in order to produce white light these three colors must always
be present

Helmholtz, however, again showed, in 1852, that a color to
our unaided eyes identical with white, was produced by com-
bining yellow with indigo. At that time yellow was consid-
ered to be a simple color, and this, therefore, was regarded as
an exception to the general rule, that a combination of three
simple colors is required to produce white. Again, it was,
and indeed still is, the general impression that a combination
of blue and yellow makes green. This, however, is entirely
a mistake. Of course we all know that yellow paint and blue

{>aint make green paint : but this results from absorption of
ight by the semi-transparent solid particles of the pigments,
and is not a mere mixture of the colors proceeding unaltered
from the yellow and the blue particles : moreover, as can easily
be shown by two sheets of colored paper and a piece of window
glass, blue and yellow light, when combined, do not give a
trace of green, but if pure would produce the effect of white.
Green, therefore, is after all not produced by a mixture of
blue and yellow. On the other hand, Clerk-Maxwell proved
in 1860 that yellow could be produced by a mixture of red
and green, which put an end to the pretension of yellow to be
considered a primary element of color. From these and other

Sir John Lubbock1 s Address. 351

considerations, it would seem, therefore, that the three primary
colors — if such an impression be retained — are red, green,
and violet.

The existence of rays beyond the violet, though almost
invisible to our eyes, had long been demonstrated by their
chemical action. Stokes, however, showed in 1852 that their
existence might be proved in another manner, for that there
are certain substances which, when excited by them, emit light
visible to our eyes. To this phenomenon he gave the name of
fluorescence. At the other end of the spectrum, Abney has
recently succeeded in photographing a large number of lines
in the infra-red portion, the existence of which was first proved
by Sir William Herschel.

From the rarity, and in many cases the entire absence, of
reference to blue, in ancient literature, Geiger — adopting and
extending a suggestion first thrown out by Gladstone —
has maintained that, even as recently as the time of Homer,
our ancestors were blue-blind. Though for ray part I
am unable to adopt this view, it is certainly very remarkable.
that neither the Eig-veda, which consists almost entirely of
hymns to heaven, nor the Zendavesta, the Bible of the Parsees
or fire-worshippers, nor the Old Testament, nor the Homeric
poems, ever allude to the sky as blue.

On the other hand, from the dawn of poetry, the splendors
of the morning and evening skies have excited the admiration
of mankind. As Ruskin says, in language almost as brilliant
as the sky itself, the whole heaven, " from the zenith to the
horizon, becomes one molten, mantling sea of color and fire;
every black bar turns into mtfssy gold, every ripple and wave
into unsullied shadowless crimson, and purple, and scarlet, and
colors for which there are no words in language, and no ideas
in the mind — things which can only be conceived while they
are visible; the intense hollow blue of the upper sky melting
through it all, showing here deep, and pure, and lightness ;
there, modulated by the filmy, formless body of the trans-
parent vapor, till it is lost imperceptibly in its crimson and
gold."

But what is the explanation of these gorgeous colors? why
is the sky blue ? and why are the sunrise and sunset crimson
and gold? It may be said that the air is blue, but if so how
can the clouds assume their varied tints? Briicke showed that
very minute particles suspended in water are blue by reflected
light. Tyndall has taught us that the blue of the sky is due
to the reflection of the blue rays by the minute particles float-
ing in the atmosphere. Now if from the white light of the
sun the blue rays are thus selected, those which are transmitted
will be yellow, orange and red. Where the distance is short

852 Sir John Lubbock's Address.

the transmitted light will appear yellowish. But as the sun
sinks towards the horizon the atmospheric distance increases,
and consequently the number of the scattering particles. They
weaken in succession the violet, the indigo, the blue, and even
disturb the proportions of green. The transmitted light under
such circumstances must pass from yellow through orange to
red, and thus, while we at noon are admiring the deep blue of
the sky, the same rays, robbed of their blue, are elsewhere
lighting up the evening sky with all the glories of sunset

Another remarkable triumph of the last half -century has
been the discovery of photography. At the commencement of
the century Wedgwood and Davy observed the effect produced
by throwing the images of objects on paper or leather pre-
pared with nitrate of silver, but no means were known by
which such images could be fixed. This was first effected by
Niepce, but his processes were open to objections, which pre-
vented them from coming into general use, and it was not till
1839 that Daguerre invented the process which was justly
named after him. Very soon a further improvement was
effected by our countryman Talbot. He not only fixed his
" Talbotypes" on paper — in itself a great convenience — but, by
obtaining a negative, rendered it possible to take off any num-
ber of positive, or natural, copies from one original picture.
This process is the foundation of all the methods now in use;
perhaps the greatest improvements having been the use of
glass plates, first proposed by Sir John Herschel ; of collodion,
suggested by Le Grey, and practically used by Archer; and,
more lately, of gelatine, the foundation of the sensitive film
now growing into general use in the ordinary dry-plate process.
Not only have a great variety of other beautiful processes been
invented, but the delicacy of the sensitive film has been im-
mensely increased, with the advantage, among others, of dimin-
ishing greatly the time necessary for obtaining a picture so that
even an express train going at full speed can now be taken.
Indeed, with full sunlight -j-J-^- of a second is enough, and in
photographing the sun itself fl0jft00 of a second is sufficient

We owe to Wheatstone the conception that the idea of
solidity is derived from the combination of two pictures of the
same object in slightly different perspective. This he proved
in 1833 by drawing two outlines of some geometrical figure or
other simple object, as they would appear to either eye respect-
ively, and then placing them so that they might be seen, one
by each eye. The "stereoscope," thus produced, has been
greatly popularized by photography.

For 2,000 years the art of lighting had made little if any
progress. Until the close of the last century, for instance, our
lighthouses contained mere fires of wood or coal, though the

Sir John Lubbock1 s Address. 358

construction had vastly improved. The Eddystone lighthouse,
for instance, was built by Smeaton in 1759 ; but for forty years
its light consisted in a row of tallow candles stuck in a hoop.
The Argand lamp was the first great improvement, followed by
gas, and in 1863 by the electric light.

Just as light was long supposed to be due to the emission of
material particles, so heat was regarded as a material, though
ethereal, substance, which was added to bodies when their
temperature was raised.

Davy's celebrated experiment of melting two pieces of ice
by rubbing them against one another in the exhausted re-
ceiver of an air-pump had convinced him that the cause of
heat was the motion of the invisible particles of bodies, as had
been long before suggested by Newton, Boyle and Hooke.
Eumford and Young also advocated the same view. Never-
theless, the general opinion, even until the middle of the present
century, was that heat was due to the presence of a subtle fluid
known as "caloric/' a theory which is now entirely abandoned.

Melloni, b}r the use of the electric pile, vastly increased our
knowledge of the phenomena of radiant heat. His researches
were confined to the solid and liquid forms of matter. Tyn-
dall studied the gases in this respect, showing that differences
greater than those established by Melloni existed between gases'
and vapors, both as regards the absorption and radiation of
heat He proved, moreover, that the aqueous vapor of our
atmosphere, by checking terrestrial radiation, augments the
earth's temperature, and he considers that the existence of
tropical vegetation — the remains of which now constitute our
coal-beds — may have been due to the heat retained by the
vapors which at that period were diffused in the eartlrs atmo-
sphere. Indeed, but for the vapor in our atmosphere, a single
night would suffice to destroy the whole vegetation of the tem-
perate regions.

Inspired by a contemplation of Graham Bell's ingenious
experiments with intermittent beams on solid bodies, Tyndall
took a new and original departure ; and regarding the sounds
as due to changes of temperature he concluded that the same
method would prove applicable to gases. He thus found him-
self in possession of a new and independent method of pro-
cedure. It need perhaps be hardly added that, when submitted
to this new test, his former conclusions on the interaction of
heat and gaseous matter stood their ground.

Tne determination of the mechanical equivalent of heat is
mainly due to the researches of Mayer and Joule. Mayer, in
1842, pointed out the mechanical equivalent of heat as a funda-
mental datum to be determined by experiment. Taking the
heat produced by the condensation of air as the equivalent of

Am. Jour. Sol— Third Series, Vol. XXII, No. 131.— November. 1881.

864 Sir John Lubbock's Address.

the work done in compressing the air, he obtained a numerical
value of the mechanical equivalent of heat There was, how-
ever, in these experiments, one weak point The matter oper-
ated on did not go through a cycle of changes. He assumed
that the production of heat was the only effect of the work
done in compressing the air. Joule had the merit of being the
first to meet this possible source of error. He ascertained that
a weight of 1 lb. would have to fall 772 feet in order to raise
the temperature of 1 lb. of water by 1° Fahr. Him subse-
quently attacked the problem from the other side, and showed
that if all the heat passing through a steam-engine was turned
into work, for every degree Fahr. added to the temperature of
a pound of water, enough work could be done to raise a weight
of 1 lb. to a height of 772 feet. The general result is that,
though we cannot create energy we may help ourselves to any
extent from the great storehouse of nature. Wind and water,
the coal-bed and the forest, afford man an inexhaustible sup-
ply of available energy.

It used to be considered that there was an absolute break
between the different states of matter. The continuity of the
gaseous, liquid and solid conditions was first demonstrated by
Andrews in 1862.

Oxygen and nitrogen have been liquefied independently and
at the same time by Cailletet and Eaoul Pictet. Cailletet also
succeeded in liquefying air, and soon afterwards hydrogen was
liquefied by Pictet under a pressure of 650 atmospheres, and
a cold of 170° Cent, below zero. It even became partly
solidified, and he assures us that it fell on the floor with " the
shrill noise of metallic hail." Thus then it was shown experi-
mentally that there are no such things as absolutely permanent
gases.

The kinetic theory of gases, now generally accepted, refers
the elasticity of gases to a motion of translation of their mole-
cules, and we are assured that in the case of hydrogen at a
temperature of 60° Fahr. they move at an average rate of
6,225 feet in a second ; while as regards their size, Loschmidt,
who had since been confirmed by Stoney and Sir W. Thomson,
calculates that each is at most yo o o*o o o o °f an *nca *n diameter.

We cannot, it would seem at present, hope for any increase
of our knowledge of atoms by any improvement in the micro-
scope. With our present instruments we can perceive lines
ruled on glass 9 0 \ 0 0 th of an inch apart But, owing to the
properties of light itself, the fringes due to interference begin
to produce confusion at distances of 1 4 ft 0 ^, and in the brightest
part of the spectrum at little more than ao^00th they would make
the obscurity more or less complete. If indeed we could use
the blue rays by themselves, their waves being much shorter,

Sir John Lulhock?s Address. 855

the limit of possible visibility might be extended to 130*000 >
and as Helmholtz has suggested, this perhaps accounts for Stinde
having actually been able to obtain a photographic image of
lines only 100^00th of an inch apart It would seem then that,
owing to the physical characters of light, we can, as Sorby has
pointed out, scarcely hope for any great improvement so far as
the mere visibility of structure is concerned, though in other
respects no doubt much may be hoped for. At the same time,
Dallinger and Eoyston Pigott have shown that, so far as the
mere presence of simple objects is concerned, bodies of even
smaller dimensions can be perceived.

Sorby is of opinion that in a length of g0oootD of an inch
there would probably be from 500 to 2,000 molecules — 500,
for instance, in albumen and 2,000 in water. Even, then, if we
could construct microscopes far more powerful than any we now
possess, they #would not enable us to obtain by direct vision any
idea of the ultimate molecules of matter. Sorby calculates that
the smallest sphere of organic matter which could be clearly
defined with our most powerful microscopes would contain
many millions of molecules of albumen and water, and it follows
that there may be an almost infinite number of structural char-
acters in organic tissues, which we can at present foresee no
mode of examining.

The Science of Meteorology has made great progress; the
weather, which was formerly treated as a local phenomenon,
being now shown to form part of a vast system of mutually
dependent cyclonic and anti-cyclonic movements. The storm-
signals issued at our ports are very valuable to sailors, while
the small weather-maps, for which we are mainly indebted to
Francis Galton, and the forecasts, which anyone can obtain on
application either personally or by telegraph at the Meteoro-
logical Office, are also of increasing utility.

Electricity in the year 1831 may be considered to have just
been ripe for its adaptation to practical purposes; it was but a
few years previously, in 1819, that Oersted had discovered the
deflective action of the current on the magnetic needle, that
Ampere had laid the foundation of electro-dynamics, that
Schweizer had devised the electric coil or multiplier, and that
Sturgeon had constructed the first electro-magnet It was
in 1831 that Faraday, the prince of pure experimentalists,
announced his discoveries of voltaic induction and magneto-
electricity, which, with the other three discoveries, constitute the
principles of nearly all the telegraph instruments now in use;
and in 1834 our knowledge of the nature of the electric current
had been much advanced by the interesting experiment of Sir
Charles Wheatstone, proving the velocity of the current in a
metallic conductor to approach that of the wave of light.

856 Sir John Lubbock's Address.

Practical applications of these discoveries were not long in
coming to the fore, and the first telegraph line on the Great
Western Railway from Paddington to West Drayton was set up
in 1838. In America Morse is said to have commenced to
develop his recording instrument between the years 1882 and
1837, while Steinheil, in Germany, during the same period was
engaged upon his somewhat super-refined ink-recorder, using
for the first time the earth for completing the return circuit;
whereas in this country Cooke ana Wheastone, by adopting
the more simple device of the double-needle instrument, were
the first to make the electric telegraph a practical institution.
Contemporaneously with, or immediately succeeding these
pioneers, we find in this country Alexander Bain, Breguet in
Prance, Schilling in Russia, and Werner Siemens in Germany,
the latter having first, in 1847, among others, made use of gutta-
percha as an insulating medium for electric conductors, and thus
cleared the way for subterranean and submarine telegraphy.

Four years later, in 1851, submarine telegraphy became an
accomplished fact through the successful establishment of tele-
graphic communication between Dover and Calais. Submarine
lines followed in rapid succession, crossing the English Channel
and the German Ocean, threading their way through the Medi-
terranean, Black and Red Seas, until in 1866, after two abortive
attempts, telegraphic communication was successfully estab-
lished between the Old and New Worlds, beneath the Atlantic
Ocean.

In connection with this great enterprise and with many inves-
tigations and suggestions of a highly scientific and important
character, the name of Sir William Thomson will ever be
remembered. The ingenuity displayed in perfecting the means
of transmitting intelligence through metallic conductors, with
the utmost despatch and certainty as regards the record ob-
tained, between two points hundreds and even thousands of
miles apart, is truly surprising. The instruments devised by
Morse, Siemens, and Hughes have also proved most useful.

Duplex and quadruplex telegraphy, one of the most striking
achievements of modern telegraphy, the result of the labors of
several inventors, should not be passed over in silence. It not
only serves for the simultaneous communication of telegraphic
intelligence in both directions, but renders it possible for four
instruments to be worked irrespectively of one another, through
one and the same wire connecting two distant places.

Another more recent and perhaps still more wonderful
achievement in modern telegraphy is the invention of the tele-
phone and microphone, by means of which the human voice is
transmitted through the electric conductor, by mechanism that
imposes through its extreme simplicity. In this connection the

Sir John Lubbock's Address. 357

names of Eeiss, Graham Bell, Edison and Hughes are those
chiefly deserving to be recorded.

Whilst electricity has thus furnished us with the means of
flashing our thoughts by record or by voice from place to place,
its use is now gradually extending for the achievement 01 such
quantitative effects as the production of light, the transmission
of mechanical power, and the precipitation of metals. The
principle involved in the magneto-electric and dynamo-electric
machines, by which these effects are accomplished, may be
traced to Faraday's discovery in 1831 of the induced current,
but their realization to the labors of Holmes, Siemens, Pacinotti,
Gramme, and others. In the electric light, gas-lighting has
found a formidable competitor, which appears destined to take
its place in public illumination, and in lighting large halls,
works, &c, for which purposes it combines brilliancy and free-
dom from obnoxious products of combustion, with comparative
cheapness. The electric light seems also to threaten, when sub-
divided in the manner recently devised by Edison, Swan, and
others, to make inroads into our dwelling-housea

By the electric transmission of power, we may hope some day
to utilize at a distance such natural sources of energy as the
Falls of Niagara, and to work our cranes, lifts, and machinery
of every description by means of sources of power arranged at
convenient centres. To these applications the brothers Siemens
have more recently added the propulsion of trains by currents
passing through the rails, the fusion in considerable quantities
of highly refractory substances, and the use of electric centres
of light in horticulture as proposed by Werner and William
Siemens. By an essential improvement by Faure of the Plant6
Secondary Battery, the problem of storing electrical energy
appears to have received a practical solution, the real import-
ance of which is clearly proved by Sir W. Thomson's recent
investigation of the subject.

It would be difficult to assign the limits to which this develop-
ment of electrical energy may not be rendered serviceable for
the purposes of man. * * *

358 W. LeConte Stevens — The Stereoscope,

Art. XLVIL — The Stereoscope, and Vision by Optic Divergence ;

by W. LeConte Stevens.

During the last twelve years, Professor Joseph LeConte has
published in this Journal a series of articles on Binocular Vision,
in one of which he refers to a gentleman with normal eyes
"who could combine ordinary stereoscopic pictures with the
naked eyes beyond the plane of the pictures, even when the
distance between the identical points was greater than the dis-
tance between the centers of his pupils." He adds, "It would
be curious to inquire, at what distance and of what size, accord-
ing to the laws of' vision, the stereoscopic image ought to seem
in this case."*

While conversing with this gentleman,f about three years
ago, it was discovered that I possessed the same power ; and
since that time no stereograph has been found on which identical
points were too far apart to secure binocular fusion With the
naked eyes. Not until last spring, however, did I begin any
careful investigation of these phenomena. Professor LeConte
has investigated the phenomena of ocular convergence very
fully, and has developed a system of diagrammatic representa-
tion far more consistent than any previously published. I have
tested all the experiments on this subject that he has described;
and my results have been either identical with his, or as closely
approximate as could be reasonably expected. To avoid repe-
tition of what has been already sufficiently established I shall
assume that the reader is familiar with trie contents of Profes-
sor LeConte's papers.:]: It will be found convenient to study
optic divergence especially in connection with the stereoscope.

In normal binocular vision the two eyes may be regarded as
human cameras occupying slightly different positions, from
which are obtained simultaneous views of the point upon which
the visual axes are converged. The apparent distance of this
point is mainly determined by the intersection of these axes, if
the optic angle is large enough to be readily appreciable. In
reading ordinary print with comfort the optic angle is rarely
less than 12°.

The method of preparing photographs for the stereoscope is
too familiar to describe. It is usually assumed that, when these
are viewed through the instrument, the lenticular prisms are so
adjusted that rays are deviated into the observer's eyes from
corresponding points of the stereograph, as if coming from
single objects in front; so that he may easily imagine his own

* III, ix, 162-163, March, 1875. \ Mr. James Wood Davidson, of New York.
% This Journal, II, vol. xlvii, pp. 68 and 153; III, vol. l, p. 33; vol. ii, pp. 1,
315, and 417 ; vol. ix, p. 159.

ioCr^Ciz--;

and Vision by Optic Divergence. 359

eyes to replace the photographer's cameras, and the convergence
of his visual axes to replace that of axes from some point in the
landscape upon which these cameras have been directed. In fig.
1 let aaf be the fore-
ground interval and
W that for the back-
ground on the stereo-
graph ; then the fore-
ground appears at A
and the background
at B.

To determine the
apparent distance of
A, let i stand for the observer's interocular distance, RL ; a for
the optic angle, EAL, and D for the apparent distance required.
Then, if a and a' be symmetrical,

From this equation it is seen that if a be reduced to zero by
making the axes parallel, D becomes infinite and there is no in-
tersection. If a be made negative by causing the axes to pass
from convergence through parallelism into divergence, D be-
comes negative and the intersection is behind the observer's
head. In either of these cases a physiological impossibility is
implied, if we accept the theory that the apparent distance of
the combined external image is determined by the intersection
of the observer's visual axes. If, therefore, distinct binocular
vision is attainable with the axes either parallel or divergent,
and any judgment of distance is possible, however faulty it may
be, this fact is sufficient to prove that the theory is imperfect,
and other elements must be sought for the determination of the
judgment of distance in vision through the stereoscope.

In normal binocular vision axial convergence is the most
important one of several elements which together determine the
apparent distance of the point of sight, provided the real dis-
tance of this be near the lower limit of distinct vision. In such
cases the formula just deduced is applicable with little or no
modification. If i stand for the distance between two photo-
grapher's cameras directed to the same point in a landscape,
the formula is also applicable to them, provided there be no lack
of uniformity in the media through which the rays pass. In
normal vision, moreover, both the focal and axial adjustments
of the eyes are consensually adapted to the distance of the ob-
ject regarded, and the deliverances of the muscular sense from
the ciliary and rectus muscles conduce to the same judgment of
distance. This judgment is the product of the past experience
of the individual, and its accuracy must depend largely upon
his acquired skill in interpreting muscular sensations, compar-

860 W. LeCkmie Stevens — The Stereoscope,

ing external relations, and remembering the results of such
comparisons. If by any means the axial adjustment can be
made to differ considerably from that which usually accom-
panies a given focal adjustment, binocular vision is to that
extent abnormal, and the resulting judgment of distance is cor-
respondingly vitiated. It will be shown that vision through
the stereoscope is in nearly all cases abnormal, and that optic
divergence is not uncommon among those who use this instru-
ment, especially among young persons whose interocular dis-
tance is small, whose eyes are normal, and whose power of
accommodation, both focal and axial, is hence large

If an observer, who possesses but a single eye, looks out upon
a landscape, the relative distance of the different objects viewed
may be roughly estimated in terms of some standard arbitrarily
chosen, so long as they are not precisely aligned with his eye.
The judgment is less accurate as the angular separation of the
objects becomes less, and as there are fewer of them at moderate
distances with which to compare the rest Always, and often
unconsciously, he employs one or more of the following ele-
ments in judging the distance and form of each object regarded.

I. Near objects subtend larger visual angles than remote
objects of equal size.

II. Near objects are seen more distinctly than those that are
remote. The illusion of distance may hence be produced by
decreasing the brightness of the object viewed, by changing the
nature of the medium, or by increasing the contrast between
light and shade.

III. Near objects, that are almost aligned with those which
are remote, partly cover them. Covering objects are judged
nearer than those covered.

IV. Familiarity with the dimensions of known objects when
near enables us to compare them when remote and thereby
judge their relative distance.

V. By moving from one standpoint to another and compar-
ing the new view with what is retained in memory of the pre-
vious one, parallax of motion thus contributes to the formation
of a judgment of both distance and form.

The mere synopsis of these elements is all that is necessary;
separately they are familiar enough, and to illustrate them
would be easy. Every one of them may be employed in the
use of each eye, either separately or in conjunction with its
companion. For distances of more than 240m the binocular
observer has no advantage except that two eyes receive more
light than one, and the combined external image hence appears
brighter and more distinct. All of them except the last may
be imitated in pictures, and some of them, notably the second,
may be heightened by the magnifying effect of lenses. In study-

and Vision by Optic Divergence. 861

ing binocular vision they must be eliminated as far as possible;
and all except the first may be nearly eliminated by using only
skeleton pictures. In ordinary stereographs their combined
effect is usually greater than that due to binocular perspective.

If for convenience we apply the term physical perspective
to the combined effect of the elements enumerated, then that
of focal and of axial adjustment may be called physiological
perspective. The latter might be regarded as mathematical if
the theory set forth at the beginning of this paper were strictly
applicable in all cases. It is well known that focal adjustment
does not vary sensibly for distances of more than 6m, and that
its effect is greatest just beyond the near limit of distinct
vision, which is also about the average distance at which a
stereoscope card is held when regarded. It is also well known
that in normal binocular vision, the convergence of axes does
not vary sensibly for distances of more than 240m. In abnor-
mal vision convergence may be diminished until the limit of
parallelism is passed; and the judgment of distance continues
to be affected by the relaxation of the interior rectus muscles,
or contraction of the exterior rectus, or by both, while the
focal adjustment is still adapted to the distance of the object in
front held as near as convenient. The judgment of distance
which results from the conflict of elements produced by this
unusual coordination of muscular actions is necessarily by no
means mathematical in accuracy.

While the possibility of securing divergence of axes for
normal- eyes has been long known, no analysis of the visual
phenomena in binocular vision by this method has appeared in
print, so far as I am aware. Professor LeConte's diagrams
show how to determine the apparent direction of the object
viewed, but he says,* "there is no point of sight." There is
certainly none determined by intersection of visual axes. In
reference to images perceived by abnormal vision, Helmholtz
says,f " we judge them according to their nearest resemblance;
and in forming this judgment we more easily neglect the parts
of the sensation which are imperfect than those which are per-
fectly apprehended." In combining stereoscope pictures by
axial divergence, either with or without the instrument, I secure
vision so clear that no defect is appreciable at any point how-
ever carefully scrutinized ; it does not seem necessary then to
assume that any parts of the sensation are neglected. The
case was very slightly otherwise during my first experiments in
divergence. He makes also the following observation, that I
translate from the French edition, which is the latest, of his work
on Physiological Optics :$ " When we compare a stereoscopic

♦This Journal, III, vol. ix, p. 163.

f Popular Lectures on Scientific Subjects, 1st series, p. 307.

X Optic Physiologique, p. 828, edition 1867.

362 W. LeConte Stevens — Tlie Stereoscope, etc.

image, observed by divergence of the visual lines, with very
remote real objects visible above the stereoscope, such as a
remote chain of mountains, the stereoscopic image appears to
us much more remote than real objects the most distant.'* The
apparent anomaly of binocular vision without convergence of
axes he refers, in this connection, to our " comparing the sensa-
tion produced with that which resembles it the most, and
which is not distinguishable from it but by feebler convergence,
that is, with what very remote objects give us. " So far as
axial divergence alone is effective, I am unable to sustain
Helmholtz's observation ; nor is it sustained by those whom I
have tested, every one of them giving results closely accord-
ant with my own, care having been taken to prevent any pre-
vious knowledge of my object in questioning them. All that
is essential is to secure axial divergence and compare the
binocular effect with the monocular effect of the same picture,
if the original landscape be not present. Before me is a
stereograph representing Alpine scenery, which I combine
binocularly, with from 2° 17' to 2° 40' of divergence, as fore-
ground and background are successively regarded. On clos-
ing the left eye, the apparent distance of a remote mountain
is not perceptibly diminished; indeed on account of the de-
creased brightness of the monocular image, the mountain
seems slightly farther. To eliminate physical perspective as
much as possible, this being always strong in pictures of land-
scapes, a stereograph is now taken, representing a white marble
statue against a dark background; the stereographic interval
can be varied at will, the card having been cut in two. Plac-
ing this in the stereoscope, the two pictures are drawn apart
until 5° of axial divergence is attained, the experiment being
made at a window from which an extensive landscape can be
seen for *the purpose of comparison. By no effort of imagina-
tion can I estimate the apparent distance of the statue to be
more than 10m. A stereograph representing a skeleton cone is
now substituted, but with the same result.

It may be safe to say therefore that if Helm hoi tz was exam-
ining, by axial divergence in the stereoscope, a picture of the
same landscape that lay actually before him, the mountains in
the picture appeared farther off than those with which they
were at once compared by normal vision with both eyes, all
the elements of physical perspective being the same in both
cases. This is probably what he meant. But his remark is
not necessarily or generally applicable when stereograph and
landscape are unrelated. Mere divergence of axes is not enough
to reverse physical perspective, but may modify it to some
extent and introduce special illusions.

[To be continued.]

M L. Nichols — Electrical Resistance, etc.

363

Art. XLVIIL — Note on the Electrical Resistance and the Coeffi-
cient of Expansion of Incandescent Platinum ; by E. L.
Nichols, Ph.D. (Gottingen).

[Read at the Cincinnati Meeting of the American Association for the Advance-
ment of Science, August, 1881.]

L In the measurement of temperatures above the red heat,
the platinum pyrometer, in one form or another, is as important
as the mercury thermometer, at ordinary temperatures. The
researches already completed, on the electric resistance and the
coefficient of expansion of platinum, and on the specific heat
of that metal, only serve, however, to remind us of the much
that remains to be done before we may hope to attain to even
a fair degree of accuracy in the measurement of temperatures
above 500°.

The present writer in order to compare the existing formulae
for the temperature of platinum from its electric-resistance, with
those by means of which the temperature is calculated from the
coefficient of expansion, and thus to gain a clearer idea of the
relative usefulness of the two methods, has determined the
resistance and the corresponding length of a platinum wire at
various temperatures between 0° and the melting point of that
metal.

II. Upon a platinum wire 04mm in diameter and 100mm long,
at points 55mm apart and equally distant from the middle of the
wire, two very fine platinum wires were welded. They served
to mark the ends of the portion of the wire to be measured,
and to make electrical connection with a shunt containing a
sensitive galvanometer. The wire was heated by the current
from a battery of forty Bunsen's cells. Its resistance was
determined by the following method.

The wire (AB) (figure 1)
together with a tangent gal-
vanometer (G) and a resist-
ance box (W) was in direct
circuit with the Bunsen's bat-
tery. A very small portion of
the current was shunted around
a&, the portion of the wire to B--
be tested, and carried through
a sensitive sine galvanometer
(g) and through a resistance
coil (w) of 5000 ohms.

Now with the above arrangement of apparatus, if w is very
much larger than r, the resistance of the wire ai, so that the

A..

364 E. L. Nichols — Electrical Resistance and the

current through ab is not sensibly less than that through the
main circuit, we shall have,

TT-C C'

where C and C are the currents through ab and through the
shunt, and r' is the resistance of the shunt.
But

C '= sin TJ#

C=tan Vk

where U is the deflection of the sine galvanometer and k! the
constant of the instrument, and where V is the deflection of the
tangent galvanometer and k the constant of the latter instru-
ment
Then

tan V k tan V T!r

sin U k1 sin U
where K = -=-, r\

The length of the wire ab was measured by bringing the two
microscopes of a comparator into such position that the terminal
(a) was in focus in the field of one of the microscopes and (J)
in the field of the other. Since these points were quite as near
the middle as the end of the wire, every change of temperature
caused a movement of both (a) and (b) ; and it was by taking
the differences of these that the true change in the length of ab
was determined. As the microscopes were provided with,
excellent micrometer scales and screws, a fair degree o£
accuracy was obtaiued by this method. Eeadings of tk^
length of the wire at 20° agreed with a series taken upon a
dividing engine of known accuracy, to within •002mxn. Thm. e
distance ab at 20° was found to be 53'5576mm.

The resistance of the cold wire was found — in terms of U, ^V
and K — by placing the wire in a napthaline bath, and obtain-
ing values of U and V with various amounts of currents. Fron2

these readings a curve was drawn with - — f? as abscissae and
° sin U

tan'V as ordinates, tan9V being taken as an expression for the

heating effect of the current. The point of this curve corres-

for the cold wire.

In measuring the resistance of the hot wire, the galvano-
meters were read simultaneously before and after each deter-
mination of the length.

Coefficient of Expansion of Incandescent Platinum. 865

The following table gives the results of the measurements,
r temperatures ranging between 0° and a point not far below
e melting point of platinum. Both resistance and length of
re at 0° are taken equal to unity.

Table I.

esistance.

Length.

Resistance.

Length.

1-0000

100000

3-7090

1-01229

1-0410

1-00002

3-7427

1-01223

] -5071

1-00125

3-7813

1-01285

1-9000

1-00289

8-8750

1*01349

2-1212

1*00380

3*8904

1-01371

2-2934

1-00456

3*9305

1-01378

2-3035

1*00489

4-0303

1-01450

2-7821

1-00732

4-0631

101469

2-8633

1-00763

4*0655

1-01495

2-9696

1-00809

4-0747

1-01499

3-3533

1-01022

4-0841

1-01514

3-3741

1-01003

4-1248

1-01540

3-4151

1-01042

4-2005

1-01567

3*6449

1-01160

4-2447

1-01632

III. Dr. Siemens has published three formulae for the varia-
on of the resistance of a platinum wire with the temperature.

The temperatures were calculated in one case (formula a)
om the heating effect of a copper ball, the specific heat of
>pper being regarded as a constant, while the other two
rmulae were derived from measurements with the air-ther-
ometer.

These formulae are :

(a) r= -039369 T*+ 00216407 T— -24127

(b) r= -002 1448 T*+ '0024187 T+-30425

here T is the absolute temperature and r the resistance of the
ire. The following formula by Benoit is also sometimes
jed for the determination of high temperatures.

(d) r=l + -002445 t + -000000572 t\

i this expression t denotes the temperature in degrees centi-
•ade.

When, as is frequently the case, it is more convenient to
easure the length of a wire than its resistance, we may employ
"atthiesen's formula,

(e) l=l0(l + -00000851 * + -0000000035 ?)

366 B. L. NichoU— Electrical Retistance and the

or we may use the uncorrected scale of the platinum ther-
mometer. The latter scale is expressed by the formula

{/) l=lt (I + -00000886 t).

These being almost the only data we possess for the calcula-
tion of tbe temperature of a hot wire, the question of their
accuracy is of some importance. The formulae may be best
compared by plotting side by side the curves which represent

them (fig. 2).

Riii
JkVM
SIM
■■I
■■
lf//J

I mm
'MM

hum*

In fig. 2, resistance is substituted for length in curves (e)
and (_/), using .for that purpose tbe measurements given in
Table I. The following table affords a further comparison of
the six formulas.

In the columns (a) to (/) are given the temperatures, calcu-
lated by tbe several formulas, at which the resistance of the
wire, compared with its resistance at 0°, is given in the column
marked "r."

Coefficient of Expansion of Incandescent Platinum. 367

Table II.

Length.

" Siemens.
6

Benoit.
d

Matth.
e

Pt.
thermom.

1-0000

1-000

0°

1*0032

2-000

325°

402°

420°

378°

342°

375°

1-0082

3000

692

812

1108

708

726

917

1-0146

4-000

1086

1244

1950

1000

1170

1623

10280

5000

1464

1682

3170

1272

1638

3100

6-000

1828

2072

•> ~ « •

1512

2158

7-000

2170

.2387

MS—*

1766

2800

8-000

2470

2692

1978

_ - _ _

_ _ _ .

«• — » •

* - .. *

A glance at the curves and at this table suffices to show how
ill-deserved is the confidence generally felt in these formulae.
The discrepancies involve differences of hundreds of degrees.

IV. The methods employed by Dr. Siemens in the measure-
ments represented by curves b and c were identical ; but the
platinum used contained slight impurities. To these impurities
the disparity was due. Dr. Siemens found that such foreign
substances as usually occur in commercial platinum affected
both the resistance of the cold metal and the law of the change
of resistance with the temperature.

Benoit's formula (d) depends for its accuracy upon the
determination of the boiling points of mercury, sulphur, cad-
mium and zinc; for which temperatures he adopted the values
given by Deville and Troost.* M. Ed. Becquerel opposed
those values at the time of their publication, and later researches
have confirmed him, at least so far as cadmium and zinc are
concerned, in thinking them to be entirely too high.

In the following table the results obtained by Deville and
Troost are compared with the more probable values given by
other physicists.

Table III.

Motnla

Boiling points.
Dev. and T.

Boiling points.

Xu.GvalB.

Other values.

Hg.

Cd.
Zn.

360°

440 j

860
1040

350°

448

446 ) (
772 \ '(
884

Reg n a ult.
Bennett,
Carnelly and
Williams,
Becquerel,

This Journal, 1878.
Quart. Jour. Chem. Soc,

1876-78.
Comptes Rendus, 57.

The substitution of these values in Benoit's formula, places
it more at variance than before with the measurements of
Matthiesen and Siemens ; a variation probably due to the

* Deville and Troost Annales de Chimie, IN, vol. lviii.

388 W. J. McOee — Local Subsidence produced by an Ice-sheet

difference of behavior noticed by the latter physicist in the
case of different specimens of platinum.

The brief discussion of the above mentioned results suffices
we think to show, that :

1st The formulae in question are based for the most part
upon unwarrantable suppositions, such as the constancy of the
specific heat of copper and of platinum ; the constancy of the
coefficient of expansion of the latter metal, and upon the accu-
racy of certain very doubtful values for the boiling points of
zinc, cadmium, etc.

2d. That, aside from the inaccuracy of those data, the vary-
ing resistance of different specimens of platinum renders any
formula for the calculation of temperature of that metal from
its electric resistance applicable only to the identical wire for
which the law of change of resistance with the temperature has
been determined.

3d. That from the data at command we are not in position
to calculate the temperature of an incandescent platinum wire
from its change of resistance, nor from its length, nor indeed in
any other manner, further than to express the temperature in
terms of the length or the resistance of the wire.

4th. That, owing to the great variations shown by different
specimens of platinum as regards its resistance, the determina-
tion of the expansion of the wire is to be preferred, whenever
practicable, to the measurement of its conductivity.

Akt. XLIX. — On Local Subsidence produced by an Ice-sheet;

by W. J. McGee.*

The influence of a polar ice-cap on the earth's center of
gravity has been computed by Croll and others on the supposi-
tion of an inflexible crust. But geological investigation has
demonstrated that the terrestrial crust is flexible, and hence
subject to local deformation. Now the problem requiring the
influence of an ice-cap on the earth's center of gravity, on the
supposition of a flexible crust, is so complex as to be incapable
of solution in the present state of knowledge ; but the local
deformation may be considered.

The subsidence of areas of deposition is a well-known phe-
nomenon, attested by unequivocal evidence in many parts of
the globe. The single instance, cited by Button ("Geology of
the Hiiih Plateaus of Utah," p. 13), of the subsidence of the ter-
restrial crust in Utah during the Cretaceous-Eocene time to the
extent of 6,000 to 15,000 feet, may be here referred to. From

* Supplementary note to p. 267 (line 33) of the last number of this Journal.

W. J. McOee — Local Subsidence produced by an Ice-sheet 369

this and other instances it appears that a mass of sediment
produces a deformation equal to its own thickness. Now since
the specific gravity of ice to average rock is something over
1 : 3, it follows that an ice-sheet three miles in thickness ought
to depress the subjacent strata about a mile.

But time is an important element in the motion of all imper-
fectly fluid bodies. The approximate numerical equivalence
between cause and effect in cases of subsidence with deposition
indicates that if sufficient time be given the rigidity of the
terrestrial crust is practically nil; though it is probable that
the function is variable and represented by an infinite series,
no terms of which are known. The time of continuance of
quaternary ice to that of the deposition of the Cretaceous and
Eocene sediments in Utah is as some unknown ratio, probably
between 1 : 100 and 1 : 10,000 ;— say 1 : 1,000. If, however,
the deformation during various times is represented by an
infinite series, the ratio between quaternary and Cretaceous-
Eocene subsidence is much higher — say 1 : 10. The subsi-
dence produced by an ice-sheet three miles in thickness ought
accordingly to be only 500 or 600 feet. It will be understood
that while it is certain that subsidence would occur, very little
value can be attached to this estimate of its amount.

The hydrostatical principles in accordance with which deform-
ation beneath a thick ice-sheet must occur, equally demand
that the crust should return to its original form after the
melting of the ice ; and it is manifest that as much time would
be required to produce this secondary as the primary deform-
ation. Assuming then that the periods of advance and retreat,
or of growth and decay of the ice are of like duration, it follows
that the earth! s surface must continue below the normal level at any
latitude, after the withdrawal of the ice, for as long a period as t/iat
during which the ice remained stationary at that latitude.

Should the application of the principles sought to be eluci-
*dated in the paper on "Maximum Synchronous Glaciation" to
any single continental area ever be attempted, the foregoing
considerations will afford a means of testing their accuracy ;
for late-quaternary depression, being accompanied by sub-
mergence in all low-lying areas, has left unmistakable traces,
not only of its occurrence but of its extent, in many localities.

Farley, Iowa, Sept. 15, 1881.

Am. Jour. Sci.— Third Series, Vol. XXII, No. 131.— November. 1881.

370 J. J. Stevenson — Laramie Oroup of Southern New Mexico

Art. L. — Note on 'the Laramie Oroup of Southern New Mexico;
by John J. Stevenson, Professor -of Geology in the Uni-
versity of New York.

In a former paper* the writer gave some notes respecting the
Laramie of Southern New Mexico, as shown in the vicinity of
Galisteo creek. Some additional facts respecting the same,
obtained during the present summer more than one hundred
miles south from Galisteo creek, may be of interest

The Laramie group is practically continuous on the east side
of the Rio Grande Valley, southward from Galisteo creek, to
certainly five or six miles beyond San Pedro, or one hundred
and fifty miles south from Santa Fe. Coal beds have been
opened near Galisteo creek, in the vicinity of the Tuerto
mountains, near the Sandia mountains, and at several other
localities as far south as San Pedro. The outcrop on the east
side of the Rio Grande Valley has been carefully traced and
mapped by Mr. J. M. Robinson, for the Atchison, Topeka and
Santa Fe railroad company. The absolute continuity of the
field is interrupted only by a few narrow cafions and the bluffs
marking the western edge of the area can be followed as easily
as those marking the eastern edge of the Trinidad coal field in
northern New Mexico.

The San Pedro locality is nearly nine miles east from the
Rio Grande, and is about twenty-three miles south-southeast
from the city of Socorro, whence it can be reached conven-
iently by a wagon road passing through the villages of San
Antonio and San Pedro ; but before long it will be more con-
venient of access, as the railroad company contemplate build-
ing a branch road to the coal.

In this southern part of the field one observes the same fea-
tures as on the Galisteo. Instead of the yellow or buff sand--
stones which predominate in the Trinidad and Cafion City coal
fields, shales prevail, and for the most part the sandstones are
soft and often argillaceous. Thin beds of hard, fine-grained
sandstone are shown, with distinct jointing and breaking into
angular fragments, which retain their sharpness even after long
exposure to the weather. When seen from a little distance
these thinner beds resemble sheets of igneous rock. As on the
Galisteo, beds of iron ore with concretionary structure are
numerous, as also are beds of ferruginous clay with cone-in-
cone structure. These ferruginous beds are not confined to the
lower part of the group. The shales are drab to black and in
many of the beds are fissile.

* This Journal, vol. xviii, p. 371.

J. J. Stevenson— * Laramie Group of Southern New Mexico. 371

At the San Pedro locality, four beds of coal were seen within
a vertical distance of barely one hundred feet. The lowest
bed has the following structure :

Upper division,

Coal ---0' 8"

Clay - 2' 0"

Coal T 4"

Shale 2' 3"

Lower division 6' 9"

Coal 4' 4"

Clay 0' 2"

Coal 2' 3"

The blossom of the next bed at nearly twenty feet higher is
somewhat more than five feet thick. The bed contains much
coal but it is so broken .by partings that perhaps the whole
may be unavailable. The third bed is but two or three inches
thick and is embedded in dark shale. The highest appears to
be little more than two feet thick, the estimate being made
from its badly weathered blossom. The dips are southward
and vary from seven to fifteen degrees.

The lowest coal bed has been opened by a slope one hundred
and fifty feet long, and a large quantity of the coal has been
tested on the railroad engines where it worked satisfactorily.
Its quality varies in different parts of the bed and the differ-
ences in physical characteristics suggest that the relation
between fixed carbon and volatile matter may vary in the sev-
eral benches. The coal from some portions closely resembles
semi-anthracite, while that from others cokes readily. This
opening is not new, coal having been obtained from it years
ago to supply Port Craig.

These beds belong at not less than two hundred feet above
the base of the group.

That this field belongs at the same horizon with the Trinidad
coal field has been announced by Mr. Lesquereux, Dr. Hayden
and the writer, as proved by the stratigraphy and by the tes-
timony of the fossil plants. In the paper already referred to
the writer stated that he had observed on the Galisteo an unex-
pected intimacy between the Laramie and the Fort Pierre and
that he had obtained Oslrea congesta from a ferruginous bed
high up in the Laramie. This intimacy is much more marked
at the San Pedro locality. Stratigraphically and lithologically
there is no means of distinguishing the Laramie from the Fort
Pierre, aside from the coal beds. Were these absent an
observer would hardly hesitate to regard the whole as one
group, for there is much less of sandstone here than on the
Galisteo. The ferruginous beds with cone-in-cone structure
appear to be wholly non-fossiliferous on the Galisteo, but at

372 A. W. Wright — Polariscopic Observations of Comet c, 1881.

the San Pedro locality these beds are fossil if erous, though not
to the same extent as the ore-beds. The presence of marine
fossils was not ascertained until just before leaving the place,
and but a few minutes remained in which to collect The
specimens therefore are such only as could be broken hastily
from the weathered surface of the beds, and in most cases suf-
fice for merely generic determination. The list as determined
by Prof. E. P. Whitfield is as follows :

Ostrea glabra ; Anomia; Corbula, 3 species; Camptonectes? ;
Tellina ?, and a fragment of some gasteropod.

Art. LI. — Polariscopic Observations of Comet c, 1881 ; by

Arthur W. Wright.

The path of this comet in the sky did not bring it into posi-
tions the most favorable for observation, but while near the
perihelion it continued for a short time each evening at a suffi-
cient altitude to escape the influence of twilight, though never
far enough above the horizon to be viewed under entirely
satisfactory conditions. Although these circumstances pre-
vented the attainment of anything like a complete series of
observations, it was found possible to establish the fact of
polarization, and even to secure some measurements. Owing
to the extreme faintness of the light, these were obtained with
some difficulty, and were limited to a small number.

The first successful observation was made on August 16,
from 9h to 10h P. M., local time. With a double-image prism,
placed before the eye-piece of a comet-seeker having an aper-
ture of three inches, and a magnifying power of about eight
diameters, the light was easily seen to be polarized in a plane
passing through the sun. That there might be no doubt upon
this point, two other persons were requested to view the images
as they appeared in the instrument. Both found one of them
fainter in certain positions of the prism, and in every case
correctly designated that one which accorded with polarization
in the direction above described, and this without any intima-
tion as to the result to be expected. The light was just suffi-
cient, when the polarimeter was applied, to enable the bands to
be seen with great difficulty, but measurements were impossible.

A few evenings later some polarimetric determinations were
obtained, the results of which are brought together in the
annexed table. The instrument and method employed were
the same as described in the account of observations upon
comet &.* Column I gives the date and local time; in column

* This Journal, vol. xxii, Aug., 1881, p. 142; Copernicus, No. 8. p. 157; The
Observatory, No. 53, p. 253.

A. W. Wright — Polariscopic Observations of Comet c, 1881. 373

II each number is the percentage of polarization derived from
ten separate measurements; column in gives the mean of these
for each evening; in column IV are given the angles of inci-
dence of the solar rays. These are obtained by graphic inter-
polation from a curve representing the angles calculated from
the ephemeris of H. Oppenheim,* for the dates there given.

II.

III.

IV.

Aug. 20, 8h 30m to 9b 30m, p. M.

134
14-2

13-8

54°6

Aug. 22, 8h 30m to 9b 15U1, P. M.

11-0
9-7

10*3

55°6

Aug. 25, 8h 30m to 9h, P. M.

10*5
11-6

110

55°-2

Aug. 27, 8h 30m to 9h, P. M. [168] [168] 54°1

The percentage for August 27 was obtained from two set-
tings of the plates only, and is entitled to less confidence than
the others. That the polarization was really increasing, how-
ever, was easily recognized by the appearance of the bands,
and their relative brightness in the two positions of the glass
plates. After this date the condition of the sky was not at any
time such as to render further determinations possible. At
the hours of the observations the last vestiges of twilight had
apparently disappeared; and a careful examination of the
neighboring regions of the heavens with the instrument failed
to give evidence of its presence, or of any polarization in the
very faint light of the sky.

A comparison of the results above given with those obtained
in the observations of comet 6, 1881,f shows that for corres-
sponding angles of incidence the polarization was decidedly
less than in the case of the latter comet. There appears also
to be a difference in the relation of the percentages to the
angles of incidence. Comet c, during the period when meas-
urements were possible, changed its position in such a way that
the angle first increased and then decreased, the change in each
case being very small. It is so little, in fact, that some uncer-
tainty must be felt as to its character, since the data of the
published ephemerides lead to considerably different values.
That of Oppenheim, however, which was employed in com-
puting the series, as above mentioned, agrees very well with
reported observations of position of the comet made during the
period covered by the dates in the table. The results found as
above indicate that the polarization, for this comet, conforms
in general to the law of variation for a gaseous medium, where
the curve representing it has the maximum at the incidence of

* Astrou. Nachr., No. 2388, p. 190. f Loc. cit.

374 A. W. Wright — Polariscopic Observations of Comet c, 1881.

45°, and changes very rapidly in the region corresponding to
the incidences given in the table.

In the case of comet 6, the largest angle of incidence was
nearly 60°, and as this diminished the polarization was seen
to diminish likewise; but it happened that at the times of
widest incidence the comet was near its perihelion. A maxi-
mum occurring with an incident angle as large as 60° would
hardly be looked for if the degree of polarization depended
upon this angle alone. If the reflecting material were wholly
gaseous the greatest polarization should be found at 45° inci-
dence ; but though a tendency toward a secondary maximum
at this angle may be suspected, the observations are not
sufficient to definitely establish its existence. The changes
actually observed are with difficulty reconciled with the sup-
position that the reflection took place from gaseous substance
alone. It is not improbable that, as the comet was nearing
the sun, and while it remained near the perihelion, some
form of volatizable matter may have been eliminated by the
increasing temperature, and that the subsequent condensation
of this gave rise to the presence of minute liquid or solid parti-
cles in the gaseous matter first thrown off. The varying pro-
portions of these two forms of matter might be the cause of
notable variations in the total amount of light polarized. It is,
of course, not to be overlooked that the substance of the coma,
and probably that of the tail, gives out light of itself. The
action just described must alter the relation of the emitted to
the reflected rays, and this would have its effect upon the
degree of polarization.

The earlier observations of comet 6, made soon after its peri-
helion passage, show occasional irregularities, and the variations
are in some cases decidedly greater than the ordinary errors of
observation. The sky at the time appeared very clear, and the
atmospheric conditions were probably not the sole cause of the
fluctuations. It seems almost certain that at this period of
great activity the polarization was subject to considerable
variations of an irregular character and comparatively brief
duration.
Yale College, October 15, 1881,

W. Rarkness — The Solar Parallax. 375

Art. LIL — On the Relative Accuracy of Different Methods of
Determining the Xoiar Parallax; by Wm. Harkness.

[The substance of this paper was read before the American Association for the
Advancement of Science, at Cincinnati, August, 1881.]

The object of this paper is to compare the various methods
of determining the solar parallax, and to show that the photo-
graphic method employed by the United States Transit of
Venus Parties in 1874 is among the most accurate known, and
should not be neglected in observing the transit of 1882.

The following notation will be employed in algebraic formulae :

a =mean distance of the earth from the sun.

a, =that distance between the earth and the sun which would
satisfy Kepler's third law.

a% =mean distance of the earth from the moon.

c =a constant such that cp=p^

E =the mass of the earth.

e = eccentricity of the moon's orbit.

e = eccentricity of the earth's orbit.

G = observed force of gravity at a point upon the surface of the
earth.

Jc = Gauss's constant for the solar system.

L =constant of the earth's lunar inequality.

I = length of simple pendulum.

M =the mass of the moon.

m =ratio of the mean motions of the sun and moon =0*07480133.

P =the constant of lunar parallax =3422'*7.

Pj=that value of the constant of lunar parallax which would sat-
isfy Kepler's third law.

p =the constant of solar parallax.

Q =the parallactic inequality of the moon.

5 =the mass of the sun.

a =geocentric latitude of the moon.

T = length of the sidereal year, expressed in seconds of mean time

=31,558,149*.
T^length of the sidereal month, expressed in seconds of mean

time = 2,360,59 18*8.
t =time.

Y =the velocity of light.
a =the constant of aberration.
y =Delaunay's constant, which is approximately sin i (inclination

of lunar orbit to plane of ecliptique), and the exact value

of which is 0*04488663. See DTL., vol. ii, 802.

6 =the time taken by light to traverse the mean radius of the

earth'^ orbit.
ji = motion of moon's node, relatively to the line of equiuoxes, in

365J days.
v =the heliocentric longitude of the earth.

376 W. Harkness — The Solar Parallax.

v1 =the geocentric longitude of the moon,
p =the equatorial radius of the earth.
pl = radius of the earth at latitude cp.
cp = geocentric latitude.
¥3r=the luni-solar precession.
£1 =the constant of nutation.

In citing authorities the following abbreviations will be used:

MAc =Meraoires de 1' Academic Royale des Sciences. Paris.

HAc =Histoire de l'Academie Royale des Sciences. Paris.

CRH =Comptes Rendus Hebdomadaires des seances de l'Acade-
mie des Sciences. Paris.

PTr = Philosophical Transactions of the Royal Society of London.

ANn =Astronomische Nachrichten.

MAS =Memoires of the Royal Astronomical Society. London.

MNt = Monthly Notices of the Royal Astronomical Society,
London.

OPM=Annales de l'Observatoire Imperial de Paris. M6moires.

WOb= Astronomical and Meteorological Observations made at
the United States Naval Observatory. Washington.

PTL =Th6orie du Mouvement de la Lune, par Jean Plana.
Turin, 1832. 3 vols. 4to.

DTL =Theorie du Mouvement de la Lune, par Ch. Delaunay.
Paris, 1860-1867. 2 vols. 4to.

Every known method of determining the solar parallax be-
longs to one or other of the following classes, namely :

I. Trigonometrical methods.

II. Gravitational methods.

III. Photo-tachymetrical methods.

We will consider them in their order.

Trigonometrical Methods.

Observations of Mars, when in opposition to the sun, and at
its least distance from the earth, constitute one of the oldest
trigonometrical methods of determining the solar parallax.
There are two ways of making the observations. Either the
planet is observed on or near the meridian, at two stations,
situated respectively in the northern and southern hemispheres;
or it is observed soon after rising, and just before setting, at a
single station. The first method will be termed the meridian
method ; the second, the diurnal method. In the meridian
method the observations may be made either with a transit
circle, or with a micrometer attached to an equatorial telescope.
In the diurnal method they may be made either with an equa-
torial telescope, or with a heliometer.

The values of the solar parallax resulting from some of the
most noteworthy attempts by the meridian method are as fol-
lows:

W. Harhness—The Solar Parallax. 377

1672. J. D. Cassini (MAc, viii, 114), 9'*5

1751. Lacaille (Ephemerides des Mouvements Celestes

depuis 1765 jusqu'en 1774. Paris, lntrod. p. 1), 10*38
1835. Henderson (MAS, viii, 103), 9*028

1856. Gilliss and Gould (IT. S. Ast. Ex. to the South.

Hemisphere, vol. iii, p. cclxxxviii), 8*495

1863. Winnecke (ANn, Bd. lix, s. 264), 8*964

1865. E. J. Stone (MAS, vol. xxxiii, p. 97), 8*943

1865. A. Hall (WOb, 1863, App. p. lxiv), 8*842

1867. Newcomb (WOb, 1865, App. II, p. 22), 8*855

1879. Downing (ANn, Bd. xcvi, s. 127), 8*960.

The following are some of the results from the diurnal
method :

1672. J. D. Cassini (MAc, viii, 107), . . 10' *2

1672. Flauistead (PTr, 1672, p. 5118),.. 10.

1719. Bradley and Pound (Gehler's Physikalisches Worter-

buch, viii, 822), _ _ _ . 10*5

1857. W. C. Bond (Gould, Ast. Jour., v, 53), 8*605

1877. Maxwell Hall (MAS, vol. xliv, p. 121), 8*789

1879. Gill (MNt, 1879, vol. xxxix, p. 437), 8*78

Owing to the comparative nearness of the asteroids, and their
small, well defined disks, it has been thought that the solar
parallax might be accurately derived from observations made
upon them in the manner just described for Mars. So far as I
know, the following are the only attempts which have been
made in that direction :

1875. Galle, from Flora (ANn, Bd. lxxxv, s. 267), -. 8'*879

1877. Lindsay and Gill, from Juno (Dunecht Observatory

Publications, vol. ii, 211), 8*765

The same method has also been applied to Mercury and
Venus, but there are great difficulties in the way of obtaining
satisfactory results from these planets.

Transits of Venus. — Until quite recently, astronomers have
believed that transits of Venus furnish by far the most accurate
means of determining the solar parallax. Such transits have
been observed by three different methods, namely: 1. By
noting the times of contact between the limbs of Venus and the
sun. 2. By observing the position of Venus upon the sun's
disk with a heliometer. 3. By photographing the sun with
Venus upon its disk, and subsequently measuring the photo-
graphs.

Contact observations. — The following are some of the results
for solar parallax obtained by different astronomers from con-
tact observations of the transits of Venus in 1761, 1769 and
1874:

378 W. Harkness—The Solar Parallax.

Transit of 1761.

1763. Hornsby (PTr, 1763, p. 494), 9''73

1763. Short (PTr, 1763, p. 340), _. 856

1765. Pingre (HAc, 1765, p. 32), 10-10

1767. Planman (PTr, 1768, p. 127), 8-49

TRANSIT OP 1769.

1770. Euler (Novi Commentarii Ac. Sc. Petropol., t. xiv),. 8*#8

1771. Hornsby (PTr, 1771, p. 579), 8*78

1771. Lalande (HAc, 1771, p. 798), 8-62

•1771. Maskelyne, 8*723

1772. Lexell, 8'63

1772. Pingre (HAc, 1772, p. 419), 8*80

1 772. Planman, 8*43

1814. Delambre (Astron. Theoriqne et Pratique, t. i, p.

xliv), 8-552

. Du Sejour (Traite* Analytique des Mouvements

Apparent des Corps Celestes, t. i, pp. 451-491),. . 8'85

1832. Ferrer (MAS, v, 286), 858

1865. Powalky (Conn, de Temps 1867 Additions, p. 22),.. 8-832

1868. E. J. Stone (MXt, vol. xxviii, p. 264), 8'91

Transits of 1761 and 1769.

1835. Encke (Abhand. der Akad. zu Berlin, 1835, Math.

KL, s. 309), 8-57 1

Transit of 1874.

1877. Airy (The Observatory, 1877, vol. i, p. 149), 8*760

1878. Tupman (MNt, 1878, vol xxxviii, p. 455), 8*846

The large differences in the parallaxes obtained by different
astronomers from the same observations are due to the circum-
stance that, as the instants of contact are rendered uncertain by
the intervention of various disturbing phenomena, many of the
observers record two or three different times, corresponding to
as many different phases which they endeavor to describe, and
thus the resulting parallaxes are influenced to a certain extent
by the interpretation put upon these descriptions. The interior
contacts give better results than the exterior ones, but in any
case the probable error is large. From sixty-one selected ob-
servations of interior contacts of the transit of December, 1874,
discussed by Col. Tupman (MNt, 1878, vol. xxxviii, 20 on page
450, and 41 on p. 453), I find the probable error of an observed
time of contact to be ±48,59, which corresponds to a probable
error of ±0"'15 in the distance between the centers of the sun
and Venus. Actual errors of from twenty to thirty seconds in
the observed times of contacts are by no means uncommon.

Observations with heliometers. — A few heliometers were used
in observing the transit of December, 1874, but I am not aware

W. Harkness — The Solar Parallax. 379

that anything has yet been published which suffices to show
how accurately they will furnish the solar parallax.

Photographic observations. — For observing the last transit of
Venus there were used at least two kinds of photoheliographs,
constructed upon widely different principles. In what follows
T shall consider only the results yielded by apparatus of the
kind used by the United States Transit of Venus parties.

As the reductions of the United States transit of Venus
observations are not yet quite completed, it is impossible to
say exactly what degree of accuracy the photographs will give;
but fortunately the same instruments which were used in De-
cember, 1874, to observe the transit of Venus at Kerguelen
Island, Hobart Town and Peking, were used in May, 1878, to
observe the transit of Mercury at Cambridge, Mass., Washing-
ton, D. C. and Ann Arbor, Mich. ; and as the transit of Mercury
photographs are completely reduced, Bear Admiral John Eodg-
ers, Superintendent of the Naval Observatory, has kindly
authorized me to make use of the results. They are as follows :

The total number of plates measured was 119, of which 25
were made at Cambridge, 30 at Washington, and 64 at Ann
Arbor. Each plate was measured by two different persons.
The errors to be considered are of four different kinds, namely :
constant and accidental errors in measuring the plates, and con-
stant and accidental errors peculiar to each station.

Each plate having been measured in duplicate, if the posi-
tions of Mercury upon the sun's disk given by the measures of
the first observer are subtracted from those given by the meas-
ures of the second observer, the mean of all the residuals thus
obtained will be the constant error due to personal equation in
reading. Its- amount for each station is

In altitude. In azimuth.

Cambridge. — O'-IO — 0"-08

Washington —0*09 + 0*08

Ann Arbor +0*15 —0*02

Thus it appears that, for the mean of the three stations, the
constant error of reading is practically zero.

If the mean of the readings by the two observers is accepted
as the truth, the probable error of the position of Mercury upon
the sun's disk, as detenmined from a single set of readings by
one observer, is

In altitude. In azimuth.

Cambridge. zbO'-lS dzO'^O

Washington. dzO'19 ±0*18

Ann Arbor ±0*24 dzO'28

The locus of the average probable error of reading therefore
lies within a circle whose radius is 0"'21.

380

W. Barkness — The Solar Parallax.

The corrections found at each station to LeVerrier's tables of
Mercury, as represented by the British Nautical Almanac for
1878, are

R. A. N. P. D.

Cambridge +08079 — 0**22

Washington +0105 —0*12

Ann Arbor +0-083 +0*47

The correction to the north polar distance, given by the Ann
Arbor plates, seems to be affected by a systematic error, but it
is doubtful if its source can be discovered because no details of
the observations were sent to the Naval Observatory, and Pro-
fessor Watson, who made them, is now dead.

The probable error of a position of Mercury depending upon
two sets of readings made upon a single photograph is

R. A. N. P. D.

Cambridge ±0"*570 ±0'*562

Washington ±0655 ±0*579

Ann Arbor. ±0*436 ±0*514

The probable errors in right ascension having been reduced to
arc of a great circle. We may infer from the mean of all the
stations that the average locus of the probable error of the
position of the planet in the heavens is a circle whose radius is
0"*553.

To exhibit yet more clearly the degree of accuracy attained
by the photographic method, a table is appended, which in-
cludes all the plates, and shows the number of residuals, both
in right ascension and north polar distance, which fall between
0"*0 and just under 0"*2, 0"*2 and just under 0"*5, etc. In
tabulating the right ascension residuals it Mas been assumed that
0"2=0801, 0"*5=08-03, 1"0=08'07, 1"*5=0810, 2"*0=08*13.

Cambridge.

Washington.

Ann Arbor.

Limits.

R. A.

N. P. D.

R. A.

N. P. D.

R. A.

N. D. P.

0/ir*0-0/y*2

0*2-0*5

0*5-1*0

1*0-1*5

1*5-2*0

• 1

2*0 and over

2 1

Theory of the Gravitational Methods.

We begin the consideration of the gravitational methods by
deriving an expression for the solar parallax in terms of the
earth's mass.

W. Harkness — The Solar Parallax. 881

If I is the length of a simple pendulum which makes one
vibration in I seconds of mean time, the observed force of|grav-
ity will be

G = £' (1)

The attraction of the earth at a point upon its surface in geo-
centric latitude (p is

- (2)

The observed force of gravity is the earth's attractive force
diminished by the resolved value of its centrifugal force. At
the equator the centrifugal force is G-f- 289*24, while in any
other latitude it is G cos y>-r 289*24 ; and the resolved part of this
force acting in the direction of the vertical is G cos9 <p-r- 289*24.
Equating the earth's attraction to the force of gravity augmented
by the centrifugal force, we have

^-GV1 + 289-W . (3)

Whence, by (1)

^ p^/ cos>\

7ra «aE \ + 289-24/ KV

If T is the length of the sidereal year, expressed in seconds
of mean time, and a, is that value of the semi-major axis ot the
earth's orbit which would satisfy Kepler's third law, we have

Le Verrier has shown that a= 1*0001410,, (OPM, ii, 60, and
iv, 103). Substituting this value in (5), and transposing

*■_ _ 4a8

tt* - Ta(S + E) (1-000141)8 (6)

Eliminating k and n between (4) and (6), and rearranging the
terms

S + E_ 4*V

IT,pI,(l-000141)»A +— SA
1 • v ' \ 289-24/

Owing to the equatorial bulging of the earth, the points
which have v/£ for the sine of their geocentric latitude are the
only ones upon the surface of the earth at which a pendulum
will vibrate as it would if the whole mass of the earth were
concentrated at its center. For that reason we take sinY=4,
and consequently cosY=f. We also put />,=c/>, and a sin p
=p. Substituting these values in (7), it becomes

382 W, Harhness — The Solar Parallax.

S+E 4*>

irc^nW-ooouiy(^™) W

^v } \433-86/

The equation sinY=i, gives y>=35° 15' 52". Adding to this
the angle of the vertical, 10' 5L", the geographical latitude is
35° 26' 43", and the corresponding value of log c is 9*999515.
If we take *=18, the value of I for latitude 35° 26' 43" is
0*992732 meters.* Substituting these values, together with
T=31,558,149 seconds of mean solar time, and />=6,378,390
meters, in equation (8), it becomes

^(tt) = 226>350>000 w

p = 609-434

3 I- ]£"

"Js + K <10)

where p is expressed in seconds of arc.

In connection with equations (9) and (10) the reader may
compare " Hansen on the calculation of the sun's parallax from
the lunar theory," MNt, 1864, vol. xxiv, p. 11; "Darlegnng der
theoretischen Berechnung der in den Mondtafeln angewandten
Storungen, von P. A. Hansen." Zweite Abhandlung, s. 271;
" E. J. Stone on the value of the solar parallax, as deduced
from the parallactic inequality in the earth's motion." MNt,
1868, vol. xxviii, p. 23 ; Le Verrier, in the CRH, 1872, t lxxv,
p. 166, and MNt, 1872, vol. xxxii, p. 322.

The equation of the parallactic inequality of the moon's mo-
tion, as given by Newcomb from the theories of Plana and
Delaunay, is

1— M »

Q = 0-24123 wX— -kt—— =7- (11)

^ 1 + M sinP(l— |raa) v '

Substituting the numerical values of P and m, and transpos-
ing, this becomes

p = [8-837088] Ql±M (12)

from which p can be found when Q and M are known. The
quantity within the square brackets is the logarithm of the
number which it represents.

In connection with equations (11) and (12) the reader may
compare PTL, t. iii, p. 13; DTL, t. ii, p. 847, equation 342;
WOb, 1865, Appendix 2, p. 24 ; MNt, 1880, vol. xl, p. 468.

The lunar equation of the earth's motion is (OPM, iv, 47)

_ M sin»' , . , , x . v

6y = - E+Mx^rpXC0S5 sin (t/ "v) (13)

* Everett, Units and Physical Constants, p. 21.

W. Harkness—The Solar Parallax. 883

in which p' and P' are the actual values of the solar and lunar
parallaxes at the instant for which 8v is required. For any
given lunation, dv will evidently attain its maximum value
when sin (i/— v)=l, that is, when the longitudes of the sun
and moon differ by ninety degrees. If now we have an ex-
tensive series of observed values of dv, covering many com-
plete revolutions of the moon's node; dv will have assumed all
possible values, the mean of which will be the constant of the
lunar inequality ; pf will have assumed all possible values, the
mean of which will be the constant of solar parallax ; and the
moon will have had all possible latitudes, the mean of which
will be zero. With P' the case will be somewhat different. It
is equal to the constant of lunar parallax, plus a series of terms
multiplied by factors made up of the mean anomaly of the
sun, the mean anomaly of the moon, the mean distance of the
moon from its ascending node, and the difference of the mean
longitudes of the sun and moon. All these terms, except
those involving the difference of the mean longitudes, will as-
sume all possible values and vanish from the mean. The
mean of all the values of P' will therefore be, P + terms de-
pending upon the difference of mean longitudes of the sun
and moon.* Turning now to the second volume of Delaunay's
theory of the moon, we find that the only term of this kind in
the lunar parallax is the one numbered (27), upon page 917,
and its value is 28//#1788 cos 2D. As we have supposed all
our observations of dv to be made when D was 90°, the value of
this term will be — 28"'18, and the mean value of P' will be
P-28"-18 = 3394'\52. Substituting the mean values thus
found in (13), and rearranging the terms, we obtain

p = 0-0164564 L (— i-~ ) (14)

In connection with equation (14) the reader may compare,
Le Verrier, OPM, iv, 100 ; Newcomb, WOb, 1855, App. II
p. 28 ; E. J. Stone, MNt, 1868, vol. xxviii, p. 24.

The Moon's Mass.

Before the solar parallax can be obtained from equations (12)
and (14), it is necessary to know the moon's mass. Let us con-
sider the different ways of determining it.

The first determination of the moon's mass was made from
the tides, by Newton, in 1687. Since then other investigators
have employed the same method, but owing to the theoretical
and practical difficulties inherent in it, their results have been
so discordant as to command very little confidence. Perhaps

* In strictness it should be the difference of the true longitudes of the sun and
moon.

384 W. Harhness—The Solar Parallax.

the most trustworthy result is that by Mr. Wm. Ferrel of the
United States Coast Survey, who found the moon's mass

from the tides at Brest — — , and from the tides at Boston

77.14

, the most probable mean being — -. (Jour. Frank. Inst,

78.64' r ° 77.5

1871, vol. lxi, p. 366.)

In 1755, D'Alembert determined the moon's mass from the
phenomena of precession and nutation, but to do this with ex-
treme accuracy seems a difficult matter. The most recent
attempt is by Mr. E. J. Stone (MNt, 1868, vol. xxviii, p. 43), who
considers that his equations are accurate to terms of the third
order in the lunar theory. With some changes of notation,
they are

Ma8 ^

(15)

in which

n = One j

A =! + --'-

B = l+^-6r3 Y (16)

«-?(•♦?-*£) J

Elimiting x and e from*the equations (15), and introducing
the sines of the parallaxes instead of the mean distances, we
get

M sin^AQS .

sin3 P »(C W - K(l) v '

which becomes

_[2-411505]_A.Q_

sin3P(C"*r-B/2) V ;

by substituting the value of S sin8;) from (9). The number
within the square brackets is the logarithm of the quantity
which it represents. Ten must be subtracted from its charac-
teristic.

We will take

y = 0-04488663
e = 0-0548993
^ = 0-0167711
pi= — 19°21'20' = —0-337818 of radius.

P = 3422"'7

W. Harkness — The Solar Parallax. 386

The value here given for e is that used by Delaunay (DTL,
ii, 802). The value of P is that found from the Greenwich
and Cape of Good Hope observations by Breen (MAS, 1861,
vol. xxxii, p. 137) and E. J. Stone (MAS, 1866, vol. xxxiv, p. 16).
Substituting these values in (16) and (18), the latter equation
becomes

1 W

^ = 47-0243 -- - 175-705 (19)

m a

In connection with equations (18) and (19), the reader may
compare PTL, t iii, pp. 25-29 ; LeVerrier, OPM, t iv, p. 101 ;
Serret, OPM, v, 324; Newcomb, WOb, 1865, A pp. II, p. 28.

About 1795 Delambre seems to have determined the moon's
mass from the lunar inequality of the earth's motion. This
involves the use of equation (14), but as we propose to employ
that equation for determining the solar parallax, we cannot
avail ourselves of it for the mass of the moon.

There is yet another way of determining the moon's mass ;
to wit, by comparing the fall of heavy bodies at the surface of
the earth with the fall of the moon in its orbit. The resulting
equation will be similar to (8), except that for the masses of the
sun and earth we must substitute the masses of the earth and
moon, and instead of 1*000141 sin p we must employ the par-
ticular value of P which satisfies equation (5) when E+M is
substituted in it for S-f E, and T is taken to be the length of a
sidereal revolution of the moon, expressed in seconds of mean
time. Designating these special values of T and P by Tx and
Px, we have

E+M__ 4^p

~W~ "" 7rpa.9^3T>/434,86\ (20)

JTVsin'P

/434-86X

Of the four methods just described for determining the
moon's mass, that depending upon the tides is not sufficiently
accurate, and that depending upon the lunar inequality of the
earth's motion is not available, for our purpose. There re-
main only the two methods represented respectively by equa-
tions (19) and (20). Let us see what results they give.

As the luni-solar precession increases continually with the
time, its value is now known very accurately. I adopt for it
the numbers used by Messrs. Newcomb and Stone (WOb,
1865, App. IT, p. 28 ; MNt, 1868, vol. xxviii, p. 43), namely
50,/#tJ78. The constant of nutation is much more uncertain.
The following are some of the best modern values:

1842. C. A. F. Peters (Num. Con. Nut., p. 37), 9"223

1844. C. A. F. Peters (Mem. Ac. Sc. St. Petersbourg, 7e

s6r. t. ill, p. 125), 9-216

Am. Joub. Sol— Third Sbries, Vol. XXII, No, 131.— November, 1881.

386 W. Harkness—The Solar Parallax.

1856. LeVerrier (OPM, t. ii, p. 174), 9-23

1869. E. J. Stooe (MAS. vol. xxxvii, p. 249), 9-134

1872. Nyr6n (Mem. Ac. Sc. St. Peterebourg, 7e ser. t. xix,

No. 2), 9-236

With SF=50"-378, formula (19) gives the mass of the moon
corresponding to three different values of the nutation constant
as follows :

D. = 9'-230 M = -i-

80-96

D. = 9'-223 M = -i—

81-15

.Q = 9'-134 M = -i-

83-65

The change in the moon's mass produced by a small change
in the constant of nutation is given by the expression

<i)=-

28-1 d£l (21)

In view of the fact that Peters attributed a probable error of
db 0"*0154 to his most careful determination of the nutation
constant, and in view of the subsequent widely differing de-
termination by E. J. Stone, it can scarcely be supposed that
the true value of the nutation is known within db 0""©2. This
corresponds to an uncertainty of ± 0*56 in the reciprocal of
the moon's mass.

The length of the sidereal month is 2,360,591-8 seconds of
mean solar time. Assuming the observed value of the con-
stant of lunar parallax to be 3422"*7, Plana's theory gives
3419"62, and Delaunay's theory 3419"59, for the value of Pr
I adopt 3419//#6. Substituting these values in formula (20),

the resulting mass of the moon is — — , and the change in

81*77

the mass produced by a small change in the adopted parallax
is given by the expression

<i)-

925 dV (22)

The value of the lunar parallax now generally adopted, de-
pends upon the investigations of Messrs. Breen and E. J.
Stone. The results of these two gentlemen agree within
0"*01. The probable error of Mr. Breen's result is not stated,
while that of Mr. Stone's is zfc 0""049. Nevertheless, it is not
unlikely that the parallax may be one or two-tenths of a sec-
ond in error. An error of 0/,#l would produce an error of
0'59 in the reciprocal of the mass.

W. Harkness — The Solar Parallax. 387

Probably the moon's mass is about — — , but it is quite pos-
sible that this estimate may be in error by one part in a hun-
dred. The precession-nutation method is considered one of the
best for obtaining the moon's mass, but equations (21) and (22)
show that neither itj nor the method by the fall of the moon
in its orbit, is likely ever to furnish the mass within one part
in a thousand. Throughout all his lunar work Hansen adopted

a mass of — , and in what follows I will assume that the true
80'

mass lies between the limits — and — .

80 83

Parallax from Gravitational Methods.

Mass of the Earth. — In 1872 LeVerrier obtained the mass of
the earth from the inequalities in the motions of Venus and
Mars, and the secular variations in the elements of their orbits,
produced by it ; and from the mass thus found he derived the
solar parallax by means of an equation similar to (10). (CRH,
1872. t. lxxv, pp. 165-172; MNt, 1872, vol. xxxii, pp. 322-
328.) He gave the resulting parallaxes without directly stat-
ing the masses, but it is readily seen that his values were as
follows :

(A). From the latitudes of Venus at the moments of the

transits in 1761 and 1769, earth's mass = — - — .

' 325,165

(B). From a discussion of the meridian observations of

Venus in an interval of one hundred and six years, earth's

1
mass = . „. .

324,575

(C). From observations of the occultation of ^a Aquarii by

Mars, October 1st, 1672. earth's mass = -— .

' ' ' 323,746

Substituting these values in equation (10), the resulting

values of the solar parallax are

A. 8"-862

B. 8-868

C. 8-875

Taking the earth's mass as unity, the change in the parallax
produced by a change of one thousand units in the mass of the
sun is given by the expression

dp — 000912 dS (23)

It is difficult to estimate the probable error of the above
values of the earth's mass, but Tisserand seems to think it

388

W. Harkness — The Solar Parallax.

may be sufficient to affect the parallax by dc 0"*07. (CBH,
1881, t. xcii, p. 658.) As the secular variations of the ele-
ments of the orbits of Venus and Mars increase continually,
they will ultimately attain sufficient magnitude to give a very
exact value of the earth's mass, and then this method will
furnish the solar paralhax with the utmost precision.

Parallactic Inequality. — Professor Newcomb found that the
value of the parallactic inequality of the moon deduced hy
Hansen from the Greenwich and Dorpat observations is 126"'46.
(WOb, 1865, App. II, p. 23.)

From 2075 Greenwich lunar observations, made between
1848 and 1866, Mr. E. J. Stone found the parallactic inequal-
ity to be 125//*36±0//,4; the probable error being estimated.
(MNt, 1867, vol. xxvii, p. 271.)

From the Washington lunar observations, made between
1862 and 1865, Professor Newcomb found the parallactic ine-
quality to be 125"46. (WOb, 1865, App. II, p. 24.)

From an extended discussion of the whole subject, pub-
lished in the MNt, 1880, vol. xl, pp. 386 to 411, and 441 to
472, Messrs. Campbell and Neison found the observed value of
the parallactic inequality to be (p. 467) either 125"*64±0"'09,
or 124//,64±0//,25 ; the difference arising from the admission
or non-admission into the lunar theory of a certain hypotheti-
cal forty -five year term.

By substituting these values of Q in equation (12) the fol-
lowing values of the solar parallax result :

Moon's Mass.

JL_

8 1

Q=124"-64

8"'182

8"*780

8"*778

8*-776

125-36

•833

•831

•829

•827

125*46

•839

•837

•835

•833

125-64

•851

•849

•847

•845

126*46

8-910

8-908

8*906

8*904

These parallaxes are but little affected by the assumed mass
of the moon, and depend almost entirely upon the observed
value of the parallactic inequality, the relation between small
changes of p and Q being

dp = 0-071 dQ (24)

The original observed values of Q are affected by personal
equation, irradiation, blurring, and any error which may exist
in the adopted semi-diameter of the moon. It is difficult to
estimate how thoroughly these quantities are eliminated from
the final result, but the remaining uncertainty probably
amounts to a considerable fraction of a second.

W. Harknesa — The Solar Parallax.

389

Lunar Inequality of the Earth. — From observations at Green-
wich, Paris and Kcenigsberg, made during the periods stated,
LeVerrier found the following values for the lunar equation of
the earth : (OPM, iv, 100)

Greenwich 1816-26

" 1827-50

Paris 1804-14

" 1815-45

Koenigsberg 1814-30

The mean is 6"'50±0"-023.

Professor Newcomb found the following additional values :
(WOb, 1865, App. II, pp. 25 and 26)

Greenwich 185 1 -64 L = 6" '56 ±0^-04

Washington 1861-65 6*51 ±0*07

With these values of L, equation (14) furnishes the following
values of the solar parallax :

L = 6'-45
6-56
6-61
6-47
6-43

Mood's Mass.

•

«v

■h

L = 6' -50
651
6*56

8"-664

•678

8*744

8"-770

•784

8-851

8"-878

•892

8-960

8"'985
8-999
9-068

It would seem that the observed value of L should be quite
free from systematic errors, because it depends upon observa-
tions of the sun which are always made in the same way. The
relation subsisting between small changes in the parallax, the
mass of the moon, and the earth's lunar inequality, are given
by the equation

(25)

dp = 1-36 dh + 0-107 d(^\

It will be difficult to determine the true value of L within
zt0//#02, and at present the uncertainty in the reciprocal of the
moon's mass is at least ±0*5. With these data the probable
error of p comes out ±0//#06.

PhotO'tachymetrical Methods.

Theory. — The photo-tachy metrical methods are quite recent,
having come into existence about 1850, when Fizeau and
Foucault made their inventions for measuring the velocity with
which light traverses moderate distances upon the surface of the
earth. From the velocity of light thus obtained the solar
parallax may be found by two essentially different methods, to
wit:

1st Deriving from the eclipses of Jupiter's satellites the time
occupied by light in traversing the mean distance between the

390 W. Harhness—The Solar Parallax.

earth and the sun, and combining this with the measured veloc-
ity of light, we have •

tanj> = ^ (26)

2d. Assuming the ratio of the earth's orbital velocity to
the velocity of light to be represented by the constant of aber-
ration, and combining that constant with the measured velocity
of light, we have

t&np = TVtanVCT; (27)

If p and V are eliminated between (26) and (27) we get

2nd

which shows the relation between a and 0.
For the constants in these equations I* adopt

p =6378-39 kilometers (Col. Clarke's value).
T=31,558,149 seconds of mean time.
^=0*016771

and the equations become

0 = [P38644]a (31)

the quantities within the square brackets being the logarithms
of the numbers which they represent. In connection with
equations (26), (27), (28), the reader may consult Corn u, OPM,
t. xiii, pp. A 299- A 301.

Velocity of Light — The following are the principal experi-
mental determinations of the velocity of light between points
upon the earth's surface :

Kilometers.

1849. Fizeau (CRH, 1849, t. xxix, p. 90), _ 315,320

1862. Foucault (CRH, 1862, t. lv, p. 796 : Recueil des tra-

vaux scientifiques de Leon Foucault, pp. 2 16-226), 298,000

1874. Cornu (OPM, xiii, 293), _ 300,400

1876. Helmert (ANn, 1876, bd. lxxxvii, s. 126), 299,990

1879. Michelson (Proc. Amer. Assoc, 1879, pp. 124-160), 299,940
1881. Young and Forbes (Nature, 1881, vol. xxiv, p. 303), 301,382

Light Equation. — The time taken by light to traverse the
mean radius of the earth's orbit is commonly called the light
equation, and there are but two determinations of it from the
eclipses of Jupiter's satellites, namely :

W. Harkness — The Solar Parallax.

391

1792. Delambre, from more than a thousand eclipses of the
first satellite (Astronomie par Jerome le Francais
(la Lande), 3me edition. Paris, 1792, t. i, Tables
astronomiques, p. 238. Also, Tables Ecliptiques
des Satellites de Jupiter, par M. Delambre.
Paris, 1817, p. vii,___ 4938'2

1874. Glasenapp (Investigation of the eclipses of Jupiter's
satellites. A dissertation for the degree of mas-
ter of astronomy, by S. Glasenapp. Published in
the Russian language, at St. Petersburg, 1874,
p. 131), ._ 500-84

Glasenapp considered the probable error of his determination
to be ±l8-02.

Aberration. — The following are the principal determinations
of the coefficient of aberration :

1728. Bradley (PTr, 1728, p. 655), 20"-25

1821. Brinkley (PTr, 1821, p. 350), _ 20*37

1840. Henderson (MAS, 1840, xi, 248), _ _ 20-41

1843. W. Struve (ANn, 1843, bd. xxi, s. 58), 20-445

1844. C. A. F. Peters (ANn, 1844, bd. xxii, s. 119), 20-503

1850. Maclear (MAS, 1851, vol. xx, p. 98), _ 20*53

1861. Main (MAS, 1861, vol. xxix, p. 190), 20-335

Solar Parallax. — The table below exhibits the various values
of the solar parallax deducible from the foregoing values of V,
0 and a by means of equations (29) and (30). I have rejected
Fizeau and Foucault's values of the velocity of light on the
ground that they are merely first approximations, the details of
wbicb have never been published ; and I have made no use of
Helmert's rediscussion of Cornu's value. The last column of
the table gives the values of a and 0 computed by means of
equation (31) from the values of 0 and a in the first column.

Velocity of
Light

299,940

300,400

301,382

Light equa'n
4938-20

8'-894

8"'880

8'-851

Aberration
20"-26

500-84

8-758

8-745

8-716

20-57

Aberration
20"-25

8"-897

8"'883

8"'854

Light equa'n
4938-02

•335

•860

•846

•817

495-09

•37

•844

•831

•802

495-94

•41

•827

•814

•785

496-91

•445

•812

•799

•770

497-76

•503

•787

•773

•745

499*19

20-53

8-775

8-762

8-734

1 499-84

392 W. Harkness—The Solar Parallax.

The relations between small changes in j?, 0, a, and V, are

given by the equations

dp = — 0-01 11 dd — 0-0295 d V (32)

dp = — 0-432 dk — 0-0295 dV (33)

where 0 is in seconds of mean time, a in seconds of arc, and V
in thousands of kilometers. To determine p with a probable
error not exceeding ± 0"'01, the probable errors of the other
quantities must not exceed the following values, namely:
0, ± 0-840, and V, ± 240 kilometers ; or a, ± 0"-016, and V,
± 240 kilometers. Whatever may be said respecting V, it is
quite certain that our present knowledge of 0 and a does not
approach this degree of accuracy. The probable error of p
seems to be at least zb 0"'05.

The photo-tachymetric method is embarrassed by serious
theoretical difficulties. 1st. As we are ignorant of the optical
constitution of inter- planetary space, we have no sure means of
passing from the velocity of light at the earth's surface to its
velocity in space. 2d. There is no rigorous proof that the
constant of aberration gives the exact ratio of the velocity of
light to the earth's orbital velocity. 3d. The velocity of light
is the velocity of transmission of a single wave, while Fizeau's
and Foucault's methods determine the velocity of transmission
of a group of waves. Lord Rayleigh has shown that these
two things are not necessarily the same. If the ordinary theory
of aberration is accepted the velocity of light to which it refers
is the velocity of a single wave, while the velocity determined
from the eclipses of Jupiter's satellites is that of a group of
waves. (Nature, 1881, vol. xxiv, pp. 382 and 460.)

Respecting the theory of aberration the reader may consult,
Ann. de Chimie et de Physique, 1818, t. ix, p. 57 ; Oeuvres
completes d'Augustin Fresnel, t. ii, p. 627 ; Stokes, in L. E.
and D. Phil. Mag. 1845, vol. xxvii, p. 9 ; 1846, vol. xxviii, p.
76 ; 1846, vol. xxix, p. 6 ; Klinkerfues, in ANn, 1866, bd. lxvi,
s. 337 ; 1868, bd. lxx, s. 239 ; 1870, bd. lxxvi, s. 33 ; Sohncke,
ANn, 1867, bd. lxix, s. 209 ; Hoek, ANn, 1867, bd. lxx, s.
193 ; Veltmann, ANn, 1870, bd. lxxv, s. 145 ; Airy, Greenwich
Observations, 1871, p. cxix ; Proceed. Roy. Soc. 1873, vol. xxi,
p. 121 : Villarceau, Conn, de Temps, 1878, Additions ; Michel-
son, this Journal, 1881, vol. xxii, p. 120.

Conclusion.

For convenience of reference the limiting values of the solar
parallax, found by the various methods described in the fore-
going pages, are presented here. It should be remarked, how-
ever, that in selecting these values the results of all discussions

W. Harkness—The Solar Parallax. 893

made prior to 1857 have been omitted ; except in the case of
the transit of 1761, and the smaller of the two values from the
transit of 1769.

L — Trigonometrical methods.

Mars, meridian observations _ _ 8"*84 — 8"*96

" diurnal observations 8*60 — 8*79

Asteroids 8'76 — 8*88

Transit of Venus, 1761 8*49 — 10-10

" " 1769 8-55 — 8*91

" " 1874_ 8-76— 8-85

II. — Gravitational methods.

Mass of the earth 8'-87 ± 0'-07

Parallactic Inequality 878 — 8*91

Lunar Inequality 8*66 — 907

III. — Photo-tachymetrical methods.

Velocity and Light Equation 8/r,72 — 8**89

Velocity and Aberration 8 '73 — 8-90

To obtain a definitive value of the solar parallax, it woujd
now be necessary to form equations of condition embodying
the relations between the various elements involved ; to weight
these equations ; and to solve for p by the method of least
squares. But what is the use ? It is perfectly evident that by
adopting suitable weights, almost any value from 8"*8 to 8"*9
could be obtained ; and no matter what the result actually was,
it would always be open to a suspicion of having been cooked
in the weighting. We only know that the parallax seems to
lie between 8"*75 and 8"'90, and is probably about 8"'85.
Attack the problem as we will, the results cluster around this
central value. All the methods give a probable error of about
=k0"*06, and no one of them seems to possess decided superior-
ity over the others. We have nearly exhausted the powers of
our instruments, and further advance can only be made at the
cost of excessive labor.

In the beginning of the eighteenth century the uncertainty
of the solar parallax was fully two seconds ; now it is only
about 0//#15. To narrow it still further, we require a better
""knowledge of the masses of the earth and moon, of the moon's
parallactic inequality, of the lunar equation of the earth, of the
constants of nutation and aberration, of the velocity of light,
and of the light equation. All these investigations can be car-
ried on at any time, but there are others equally important
which can only be prosecuted when the planets come into the
requisite positions. Among the latter are observations of Mars
when in opposition at its least distance from the earth, and
transits of Venus.

394 C. D. Walcott — Nature of Cyathophycus.

Id 1874 all astronomers hoped and believed that the transit
of Yenus which occurred in December of that year would give
the solar parallax within 0"*O1. These hopes were doomed to
disappointment, and now, when we are approaching the second
transit of the pair, there is less enthusiasm than there was eight
years ago. Nevertheless, the astronomers of the twentieth
century will not hold us guiltless if we neglect in any respect
the transit of 1882. Observations of contacts will doubtless be
made in abundance, but our efforts should not cease with them.
We have seen that the probable error of a contact observation
is ±0//#15, that there may always be a doubt as to the phase
observed, and that a passing cloud may cause the loss of the
transit On the other hand, the photographic method cannot
be defeated by passing clouds, is not liable to any uncertainty
of interpretation, seems to be free from systematic errors, and is
so accurate that the result from a single negative has a probable
error of only db0"*55. If the sun is visible for so much as fif-
teen minutes during the whole transit, thirty-two negatives can
be taken, and they will give as accurate a result as the observa-
tion of both internal contacts. In view of these facts, can it be
doubted that the photographic method offers as much accuracy
as the contact method, and many more chances of success ?

The transit of 1882 will not settle the value of the solar
parallax, but it will contribute to that result, directly as a
trigonometrical method, and indirectly through the gravita-
tional methods with which the final solution of the problem
must rest. As our knowledge of the earth's mass may be
made to depend upon quantities which continually increase
with the time, it will ultimately attain great exactness, and
then the solar parallax will j^e known with the same exactness.
Long before that happy day arrives the present generation of
astronomers will have passed over to the silent majority, but
not without the satisfaction of knowing that their labors will
contribute to that fullness of knowledge which shall be the
heritage of their successors.

Washington, D. C, October, 1881.

Art. LIII. — On the Nature of Cyathophycus ; by C D. Walcott.

This genus was originally described by me under the im-
pression that the form was an alga of a peculiar appearance.*
On reading the observations of Professor R P. Whitfield,
on the nature of Dictyophyton and its affinities to certain
sponges, f it was instantly suggested that Cyathophycus was
probably a member of the same group. A special effort was

* Trans. Albany Institute, vol. x, 1879. f This Journal, xxii, July, Aug., 1881.

Chemistry and Physics. 395

made to obtain perfectly preserved specimens of the genus,
and with such success that the reticulate structure mentioned
in the original description was found to be formed of a hori-
zontal and perpendicular series of narrow bands crossing each
other at right angles so as to form a network with rectangular
interspaces, the narrow bands being formed of thread-like
spiculae resting on, or one against the other. The spiculae
differ in size; some are filiform while others are stronger and
more prominent, and all appear to be replaced by pyrite as in
the Devonian specimens studied by Principal Dawson and Pro-
fessor Whitfield. Through the kindness of Professor Whit-
field I have had the opportunity of examining the specimens
referred to by him, and now have little doubt but that the
Utica slate form belongs to the same class, although probably
differing generically from the Devonian species, and is an earlier
representative of this interesting group of sponges.

Cyathophycus reticulatus presents a beautiful appearance when
a large number of specimens are flattened out on a slab of the
dark slate. Each individual lays free from its associates and
the striking resemblance to Eupleciella is seen at a glance,
although the convex summit of the latter genus is absent and
the margin curves over and downward on the inside to a consid-
erable distance at least, how far is yet unknown. The cylin-
drical forms vary in length from 10 to 350mm, and the spheroidal
species, C. subsphericus, from 3 to 60mm in diameter, each species
preserving the rounded rim of the circular aperture at the
summit.

SCIENTIFIC INTELLIGENCE.

I. Chemistry and Physics.

1. International Congress of Electricians. (Letter from Pro-
fessor G. F. Barker, of the United States Delegation, dated Paris,
Oct. 1st, 1881.) — My duties here as Commissioner, as Delegate,
and now as a member of the Jury, have been, and still are, so
pressing that 1 have been obliged to forego letter writing almost
entirely. I have tried too, to put together some points of interest
for the readers of the Journal, but have thus far been quite unable
to complete anything.

The Exhibition as a whole has been a decided success. It has
brought together an immense mass of highly interesting material.
There are in all something over 1500 exhibitors, of which one half
are French, 155 Belgian, 115 English, 114 German, 81 Italian, 72
American, 39 Austrian, 32 Russian, 21 Swedish, 13 Swiss, 17
Spanish, 13 Norwegian, 11 Dutch, 5 Danish, and 2 Japanese. Of
decided novelties, there are more in the United States section

896 Scientific Intelligence.

than in any other. Edison has made a wonderful exhibition of his
inventions and his rooms are thronged continually. The principle
discovered by him that an electric current varies friction, the so-
called motograph principle, together with the applications of it
practically, are beautifully illustrated. The principle of the vary-
ing resistance of bodies which imperfectly conduct, when they are
subjected to pressure, a principle which he was the first to investi-
gate and to apply, is exhibited in a large series of instruments,
one set of which traces the progress of development of the carbon
telephone. The system of incandescent lighting which he has
perfected is shown in all its details, from the unique dynamo-
machine of low resistance and high electromotive force, the street
conductors with their connections, safety-catches, expansion-caps,
etc., the ingenious meter and the house conductors with their in-
combustible covering, to the fixtures with double conductors and
safety catches, and lastly to the incandescent lamp itself. Dolbear
exhibits a new electro-static telephone which performs admirably
and which consists simply of two thin metal plates, connected to
the secondary wire by an induction coil. They are oppositely
charged by the coil and so attract each other. Gray's harmonic
multiple telegraph is in successful operation and Bell's original
photophone is also exhibited. The most original thing exhibited
in the French section is the secondary battery ; Plante" exhibits
several forms of it, Faure shows the improvement which he made
by covering the plates with minium, and lastly Meritens is work-
ing a still newer form, in which only lead plates are used, but a
large number of them are put in a small space. In the historical
line the collection in the Exhibition is unrivaled. The pile of
Volta, the electroscopes of Galvani, the thermopiles of Nobili and
Melloni, the electro-magnetic induction ring of Faraday, the first
magneto-machine of Pixii, the rheostats and telegraphs of Wheat-
stone, the telegraphs of Soemmering, of Steinheil and of Gauss and
Weber, the continuous current-machine of Pacimotti, the electro-
thermic and electro-motor apparatus of Becquerel, the electro-
capillary apparatus of Lippmann ; all these and many more are
here collected. And as for arc lights, the Exhibition at night is
like day. The Brush machine and light are in great favor. A
large lamp of this sort just put up has carbons two inches in
diameter, and is claimed to give a light of 80,000 candies.

2. Elasticity and Motion. — Sir W. Thomson is led from the
consideration of various experiments with fluids and solids and
the study of smoke rings to speculate upon elasticity as an evi-
dence of motion. The kinetic theory of gases requires that the
molecule or atom shall be elastic. "But this kinetic theory of
matter is a dream and must remain so until it can explain chem-
ical affinity — electricity, magnetism, gravitation and inertia."
The writer looks forward to a greater generalization which shall
include elasticity as a form of motion. — Roy. Inst, of Great JBrit-
ain, March, 1881. . j. t.

Chemistry and Physics. 897

3. Efficiency of Spectroscopes. — F. Lippich discusses the point
whether it is more advantageous to increase the dispersion or to
increase the magnifying power of the telescopes of a spectroscope.
A mathematical discussion of the subject is given and the folio *r-
iug conclusion is reached: The common impression that it is
better to increase the dispersion instead of the magnifying power
of the telescope is true only when the number of prisms does not
exceed a certain number (from four to live). The author has
constructed a spectroscope of two flint glass prisms, through
which the light passes twice, provided with a telescope of magni-
fying power from fifty to seventy times, which excels in its per-
formance that of a spectroscope of from twenty to twenty-eight
flint glass prisms which has a telescope which magnifies only ten
times. Seven lines are seen with the author's spectroscope be-
tween the D lines. — Centra l-Zeit. f. Opt. u. Mech., 49 and 61, 1881.

J. T.

4. Niagara Falls as a source of Energy. — Sir Wm. Thomson
thus sums up, in his British Association Address, the conclusions
he has reached in regard to the utilization of the energy of
Niagara Falls.

" 1. Apply dynamos driven by Niagara to produce a difference
of potential of 80,000 volts between a good earth connection and
the near end of a solid copper wire of half an inch (1*27 centime-
ters) diameter, and 300 statute miles (483 kilometers) length.

" 2. Let resistance by driven dynamos doing work, or by elec-
tric light, or, as I can now say, by a Faure battery taking in a
charge, be applied to keep the remote end at a potential differing
by 64,000 volts from a good earth plate there.

"3. The result will be a current of 240 webers through the
wire taking energy from the Niagara end at the rate of 26,250
horse power, losing 5,250 (or 20 per cent) of this by the generation
and dissipation of heat through the conductor and 21,000 horse
power (or 80 per cent of the whole) on the recipients at the far end.

"4. The elevation of temperature above the surrounding atmos-
phere, to allow the heat generated in it to escape by radiation and
be carried away by connection is only about 20° Centigrade ; the
wire being hung freely exposed to air like an ordinary telegraph
wire supported on posts.

"5. The striking distance between flat metallic surfaces with
difference of potentials of 80,000 volts (or 5,000 Daniells') is only
eighteen millimeters, and therefore there is no difficulty about the
insulation.

" 6. The cost of the copper wire, reckoned at 8d. per pound, is
37,000/., the interest on which at five per cent is 1900/. a year.
If 5,250 horse power at the Niagara end costs more than 1900/. a
year, it would be better economy to put more copper into the
conductor; if less, less." — Nature, Sept. 8, 1881, p. 435. J. t.

5. Change of plane of polarization of Heat rays by Electro-
magnetism. — Leo Grunmach reviews the work of previous experi-
menters and arrives at the following conclusions :

398 Scientific Intelligence.

(1.) A change of the plane of polarization of the heat rays can
be produced in solid and fluid bodies by electromagnetism.

(2.) The magnitude of this change is different for different sub-
stances. The rotation is greater the greater the index of refraction
of the substance.

(3.) The magnitude of the rotation in dia therm a nous bodies is
proportional to the intensity of the current.

(4.) The magnitude of the rotation in a diathermanous body,
placed between the poles of a magnet, is proportional to the
magnetic force employed.

(5.) It also increases with the length of the layer of the sub-
stance : but this relation can not be computed from the length of the
layer. — Ann. der Physik und Chemie, No. 9, 1881, p. 85. j. t.

6. Electro dynamic - Balance. — H. Helmholtz provides an
ordinary balance with two spirals of copper wire, in place of the
pans. Beneath these spirals are also two spirals of larger radius.
The terminals of these spirals are so arranged that one of the
movable spirals is attached and the other repelled. The conditions
of sensibility are discussed and the author concludes that the cur-
rent which is equilibrated by one gram can be measured to go*00
of its value. — Ann. der Physik undChemie,N o.9, 1881, p. 52. j. t.

7. Change of the thermo-electric condition of iron and steel
by magnetization. — V. Strouhal and C. Barus confirm the obser-
vation of Sir W. Thomson that a longitudinally magnetized iron
wire is thermo-electrically more positive than a non-magnetic iron
wire. Their results show that the changes in the thermo-electric
condition of iron can not be used to indicate the hardness of the
iron or steel. The thermo-electric current between pieces of iron
of different magnetic conditions flows in the opposite direction from
that which arises between pieces of different degrees of hardness.
In other words it flows from the better conductor to the worse
conductor. — Ann. der Physik undChemie, No. 9, 1881, p. 54. j. t.

8. Principles of Chemical Philosophy ; by Josiah Parsons
Cooke, Erving Professor of Chemistry and Mineralogy in Har-
vard College. Revised edition, 623 pp., 8vo. Boston, 1881,
(John Allyn). — The first edition of Professor Cooke's valuable
work on Chemical Philosophy was published in 1868. The years
which have elapsed since then have brought fewer radical changes
in the philosophy of chemical phenomena than those which imme-
diately preceded, but the advances which have been made are
hardly less important. The new edition is written from this ad-
vanced standpoint, and while it contains all the excellent features
of the former it embraces also much that is valuable and new.
The student who will faithfully read the successive chapters, and
together with that, work out the many practical problems, cannot
fail to gain a clear, connected and logical knowledge of the
fundamental principles in chemical philosophy.

9. -.4 Manual of Sugar Analysis, including the applications in
general of the analytical methods to the Sugar Industry, with an
Introduction on the Chemistry of Cane-sugar, Dextrose, Levulose

„ Geology and Mineralogy. 399

and Milk-sugar, by J. H. Tucker, Ph.D. 353 pp. 8vo. New
York, 1881 (D. Van Nostrand). — In consideration of the great
importance of the sugar industry it is a matter of surprise that up
to this time the various topics connected with the analytical por-
tions of the subject have never been systematically discussed in
any single volume in the English language. This deficiency the
author has aimed to fill. The opening chapters of his work are
devoted to the chemistry of the several kinds of sugar. Follow-
ing these the methods used in the examination of sugars are

• described; first the determination of the specific gravity, then
the optical method of study, and finally the chemical methods.

t The last are extended over a series of chapters giving the method
of analysis of raw sugar, of molasses and syrup, of cane and cane
juice, beet and beet juice, of the waste products, of glucose or
starch sugar, and so on. The concluding chapters are devoted to
the chemistry of animal charcoal. The book contains a large
amount of useful information which will be hardly found else-
where in so convenient a form.

II. Geology and Mineralogy.

1. Report on the Geology and Resources of the Black Hills
of Dakota ; by Henry Newton and Walter P. Jenney.
U. S. Geogr. and Geol. Survey of the Rocky Mountain Region, J.
W. Powell in charge. 566 pp. 4to, with an atlas folio, 18 plates,
in 4to, and many wood-cuts. Washington, 1880. (Copy of the
work received in September, 1881.) — The Geological Report,-
which occupies two hundred pages of this volume, is based on the
observations of Mr. Henry Newton, made in 1875, in accordance
with instructions from the Secretary of the Interior, and was pre-
pared for the press from his nearly finished manuscript by Pro-
fessor Jenney. Mr. Newton was a graduate of the School of
Mines of Columbia College, New York ; and the volume opens
with a biographical sketch, by Professor Newberry of that School,
of the young geologist, who died in 1877, while engaged *in a
second but private visit to the region for further explorations.
The Report contains, after its historical introduction, a careful
description of the successive formations of the region, which in-
clude besides the Archaean and volcanic or igneous rocks, the
Silurian, Carboniferous, overlying " Red Beds " containing gyp-
sum with some impure limestone referred provisionally to the
Triassic, the Jurassic, Cretaceous. A large number of fossils
were collected, and descriptions of them by Mr. Whitfield, with a
general view of all thus far known from the Black Hills, occupy
135 pages of the volume, and their illustrations 16 of the plates.

The results show that the horizon of the Primordial beds is about
the same with that of Wisconsin ; that the Subcarboniferous and
Permian groups could not be identified, while the Carboniferous
is well represented by its mollusks and coals; that the Jurassic
beds are full of fossils, as first made known by Hayden's survey in

400 Scientific Intelligence.

1857, but have as yet afforded no Gasteropoda; that all tfee-for-
mations are conformable to one another from the Cretaceous to
the Primordial. The volcanic peaks occur over the part of the
Hills north of the parallel of 44° 10', without any linear arrange-
ment or special relation in distribution. On the northeast margin
of the Hills is Bear Butte ; on the northwest side, in Red Valley,
there are Inyan Kara, the two Sun Dance Hills, Warren Peaks,
and another unnamed ; on the Belle Fourche, Mato Tepee or Bear
Lodge, the three Little Missouri Buttes ; within the area, Custer,
Terry (the crowning peak of the group), Crow Peaks and Black
Butte, besides others less conspicuous. The rock of the cones is
mostly sanidin trachytes, partly rhyolitic. No evidence of over-
flows was found, with a single small exception, as if there had
been simply an extrusion of densely viscid material.

The peaks are cones, with sometimes regular craters, and vary
in height above the valley at their base, from 300 to 1800 feet.
Custer Peak is 675 feet above its base and 6,950 above the sea.
Bear Butte is 1,200 feet above its base and only 4,570 above the
sea, being about six miles from the edge of the foot-hills. Inyan
Kara is 1,300 feet above the bed of the creek of the same name,
and 6,600 feet above the sea.

Bear Lodge " is a great rectangular obelisk of coarsely porphyritic
sanidin-trachyte, with a columnar structure, giving it a vertically
striated appearance, rising 625 feet almost perpendicularly from
its base. Its summit is so entirely inaccessible that the energetic
explorer, to whom the ascent of an ordinarily difficult crag is but
a pleasant pastime, as he stood at its base could only look upward
in despair of ever planting his feet on the top." The height
above the Belle Fourche is 1,126 feet, and its height above the
sea approximately 5,260 feet ; the width at bottom is 796 feet
and at top 376 feet. In outline it is like the now unfinished
Washington Monument. The columns of the columnar trachyte
are over 600 feet in length and rise perpendicularly from a seem-
ingly massive base. "It is exceedingly difficult," writes Mr.
Newfon, " to account for this structure as a result of cooling by
comparison with any known basaltic phenomena."

Another remarkable feature of this locality is the undisturbed
condition of the surrounding Potsdam sandstone; at a distance of
but 50 to 75 feet from the base no evidence of any tilting could
be detected, but the sandstone is "converted for some distance
into a compact white quartzite."

The Little Missouri Buttes have a height of but 400 to 500 feet.
They stand on the Dakota sandstone; but this floor-rock " could
not be ascertained to exhibit any disturbance or change of struct-
ure due to the proximity of the igneous matter. The rock is green-
ish-gray trachyte, and there is also at the base, in one or two local-
ities, (what is not mentioned as occurring about the other peaks)
an exceedingly light and cellular rock, yellowish in color, very
like a volcanic tufa or rhyolite breccia, including fragments of
both sandstone and rhyolite.

Geology and Mineralogy. 401

*v.

From these facts the conclusion is arrived at that the time of
eruption was later than the Dakota and Fort Benton groups
of the Cretaceous anfl before the Miocene.

The rocks of the Hills were examined microscopically by Mr.
J. H. Caswell, whose report occupies the last fifty-five pages of
the volume and is illustrated by two colored plates. The report
recognizes among the volcanic rocks trachyte, rhyolite, and pho-
nolite, and the rhyolyte- trachyte was under the forms of volcanic
glass, pitchstone, pearlstone, spheruiite, etc. The trachyte in-
cludes sani din-trachyte and sanidin-oligoclase-trachyte ; biotite,
hornblende, magnetite and apatite are often present, and the crys-
tals of biotite have sometimes a border of magnetite. The pho-
nolite contains much nephelite and some of it hornblende. The
sanidin crystals in the trachyte from the top of Warren Peak are
one to two inches long.

The volume contains also chapters on the Mineral Resources
and climate of the Black Hills by Walter P. Jenney, on the
botany, by Asa Gray, and on the astronomical work of the expe-
dition and the barometric hypsometry, by H. P. Tuttle.

2. Primitive Industry, or Illustrations of the Handiwork in
Stone, Bone and Clay of the Native Races of the Northern
Atlantic Seaboard of America ; by Charles C. Abbott, M.D.
560 pp., 8vo, Salem, Mass. (George A. Bates.) — Mr. Abbott has
done good service to ancient American history in the preparation
of this well systematized and well illustrated work. The region
which he surveys embraces New England and the States of New
York, New Jersey and Pennsylvania ; but the wide range of his
knowledge enables him to make comparisons with related facts
from other parts of the country. Besides treating of implements
of stone, bone and clay, the author mentions many examples of
implements of copper and describes various shell-heaps — in all his
chapters citing freely from previous publications on the subject.

The author's discoveries of flint implements in the stratified drift
in the valley of the Delaware near Trenton, and the drift phenom-
ena of the regions east, west and north, are the subjects of the
two concluding chapters, the first of them by Dr. Abbott, and the
second, on the antiquity and origin of the Trenton Gravel, by
Prof. H. C. Lewis, of the Geological Survey of Pennsylvania. Dr.
Abbott gives drawings of several of the specimens discovered,
describes them as of hard argillite, and more rudely made than
the ordinary implements of the country, and regards them as the
work of the most ancient race of man on the continent, such as
existed here before the disappearance of the ice of the Glacial era
— and probably akin to the Eskimo. He refers to the occurrence
of a tooth of the Reindeer (Rangifer Caribou), from the Trenton
gravels, found by the late Prof. T. A. Conrad; to remains of the
same species and of the bison, " in an ordinary rock-shelter " near
Stroudsburg, Pennsylvania, along with marks of fire that sug-
gested the idea of a feast on the bison by the men of the time ; to
the occurrence in New Jersey of antlers of the Greenland Rein-

Am. Jour. Sol— Third Series, Vol. XXII, No. 131.— November, 1881.

402 Scientific Intelligence.

deer u in the gravel that covers everywhere the older formations "
mentioned by Prof. E. D. Cope (GeoL New Jersey, 1868, pt 740);
and the long known facts respecting the existence in Kentucky of
remains of the Moose, Cariboo, Reindeer, Mask Ox and other
northern Mammals ; and regards Palaeolithic man as a resdent of
the continent in the same era.

Mr. Lewis treats in detail of the stratified deposits of the Dela-
ware, the position of the terminal moraine across the country, the
origin of the deposits, and the antiquity of man. His codcIusioo
is that the deposits are apparently post-Glacial, and probably were
deposited by the flooded rivers at a period immediately following
the last Glacial epoch upon the Delaware river. The view that
there was more than one Glacial epoch over the region appears to
require more evidence than has yet been presented ; and if not a
fact the opinion of Mr. Abbott will probably be sustained.

3. M. E. Wadmrjyrth on the Origin of the Iron Ores of
the Marquette District. — The notice of this paper, on page 320,
does Mr. Wads worth injustice. Its criticisms derived their force
in part from the fact stated in the notice that, although the
paper mentions the qualifications needed for successful investiga-
tion, it contains no "detailed facts, sections, or description of
rock-slices," which the qualified investigator should have pre-
sented. Since the notice appeared Mr. Wadsworth has drawn my
attention to the fact that his memoir u On the Geology of the
Iron and Copper Districts of Lake Superior," published over a

Jrear ago, contains details of the kind asked for. I had over-
ooked this, having read and noticed the memoir, soon after its
publication, as far as the subject of copper was concerned, bat
not its earlier half on the iron districts. This is a reason for the
oversight but not an excuse for it. I take, therefore, this earliest
opportunity to withdraw the derogatory remarks made in this
connection. In addition I here transfer to this Journal, from his
memoir, the larger part of the section on the "Jasper and Iron
Ore," with a portion of his concluding statements. His account
of his observations is illustrated by a number of figures showing
the relations of the ore, jasper and schists, which are here omitted.
He does not, however, give any drawings from microscopic views
of thin rock-slices and, as he states, refers to the facts thus ob-
served only in a general way.

1 have also here to state that my remark on the banded struc-
ture (page 320), does not meet the argument he presents, which
aims to show that since banding occurs in both igneous and met-
amorphic rocks, it cannot be distinctive of either.

With regard to Mr. Wadsworth's method of speaking of the
labors and conclusions of others I have nothing further to say.

I add a word here on the bearing of the facts from other
Archaean regions, especially those relating to the question of con-
formability, on the Marquette question, a point not appreciated
in Mr. Wadsworth's discussions.

Of all the evidence used to prove a sedimentary origin of the

Geology and Mineralogy. 403

ore-deposits and schists, that of conformability between them is
the one most relied on by geologists, and the most decisive. Mr.
Wadsworth has considered it with reference to the Marquette
iron ore, and, disagreeing with other observers, has decided the
question adversely. But geologists who have studied, with that
and other points in view, the widest range of Archasan iron
regions — believing that they are alike in mode of origin — have
reached the general conclusion that the ore and schists of all, the
Marquette included, are conformable in bedding, and hence that
they are metamorphosed sedimentary deposits. My own exami-
nations on this point, at localities in New Jersey, New York and
Connecticut, have confirmed me in the same view ; and, with
others, I believe it will be found that any apparent unconforma-
bility in bedding is local and a consequence of the disturbances
— the flexures, fractures, faultings and attendant changes — which
these oldest of beds have undergone. j. d. d.

4. On the Jasper and Iron Ore of the Marquette Region ; by
M. E. Wadsworth. — In the Marquette region, the country rock
is of a varying nature, but is mainly composed of schists (largely
chloritic), argillites, and quartzite, in that part of the district
visited by us. Associated with these rocks is the jasper, which is
acknowledged on every hand to be an inseparable part of the iron
ore formation. The origin of one gives the origin of the other.
Their interdependence is such, and has been so regarded, that the
relations of one to the country rock give the relations of the other.
The two have been so fully described in the past, that it is only
necessary to briefly describe them here.

The common form is that of interlaminations of jasper and iron
ore, the laminae varying from extreme tenuity to considerable
thickness. In some places the jasper predominates, in others the
ore. In the last case we have a more or less valuable ore, accord-
ing to the amount of the siliceous material, which, however, may
exist only in a mere trace. The purer parts form large masses,
that are mined, and which graduate into the jasper, or ore con-
taining so much jasper as to be unfit for working. The workable
parts are frequently lenticular in form, although often irregular.
The irregularity of the ore mass, its passage into the jaspery ores,
and the uncertainty where the next mass will be found, are
among the chief difficulties of the miner. The origin of the jas-
per and ore becomes then a problem of great economic import-
ance, as do also the relations of both to the country rocks. The
permanence and extent of the formation, whether it is in the form
of vein deposits, eruptive (intrusive or overflow) masses, or sedi-
mentary deposits, are questions in which the capitalist and miner,
whether they will or not, are most deeply interested. As they
have never been regarded as vein deposits, there remains for us
only the question whether the jasper and its associated ores are
eruptive or sedimentary in origin.

Lest there be some misunderstanding as to the reason for thus
dismissing the theory of the ores here being vein deposits, we

404 Scientific Intelligence.

would remark that the question has been ably and fully disoussed
before in the works of previous observers. Furthermore, while
veins on a small scale are occasionally seen, we were unable to
find upon either the jasper or its associated ore a single character
belonging either to a vein or an infiltration deposit. It therefore
seems unnecessary to discuss the vein or infiltration theory here.

As both the eruptive and sedimentary origin of the jasper and
the ore have been advocated by some of the most eminent geolo-
gists in this country, it is necessary that the question should
be answered by the facts, and not by any preconceived theory or
idea. The question now is what are the facts, and their most
probable explanation. The first and most important thing to be
observed in deciding this is the relation of the jaspery formation
to its country rocks.

This relation is well shown in and about the Lake Superior
mine at Ishpeming. On the north side of one of the abandoned
pits just east of the main workings, the junction of the jasper and
ore with the chlorite schist was observed and figured. Specimens
were also taken that show the contact. The junction of the two
is very irregular, the banding of the jasper and ore following the
irregularities of this line, while the schist is indurated and its
laminae bear no relation to the line of contact. Stringers of ore
project into the schist, which near the jasper is filled with octahe-
drons of magnetite. The schist loses its green color generally,
and becomes apparently an indurated argillite. The contact and
relations of the two rocks are not such as are seen when one sedi-
mentary rock is laid down upon another, but rather that observed
when one rock is intrusive through another; and in this case the
intrusive one is the jasper and its associated ore. On the south
side of the same pit the jasper bows in and out in the schist,
forming at one place a projecting knob whose banding follows its
contour. Lying against it is a long arm of jasper, similarly
banded, which ends in a rounded knob. In the southwest corner
of the same pit a dike of very fair hematite ore about one foot in
width breaks at an angle of 15° across the argillite and schist,
whose lamination is vertical. Wherever the unbroken contact of
the jasper and ore with the schist could be observed, that junction
is seen to be an eruptive one, on the part of the former. At the
School-house mine east of the Lake Superior mine, the jasper
forms a dike with a knob-like ending, the lamination (banding)
following the curvature of the sides. The contacts between the
ore and schist were well-marked eruptive ones. Overlying the
ore was found on one side a ferruginous and quartzose breccia and
conglomerate composed principally of the ruins of the underlying
ore and jasper. A similar but finer-grained rock, mostly a quart-
zite, forms the hanging, or better the fallen wall of the New
York mine. This is composed, in like manner, chiefly of the
debris of the underlying ore and jasper. Mr. Brooks's statement
regarding the " quartzite " of the Marquette district is undoubt-
edly true of this rock, that when he finds the " quartzite," adja-

Geology and Mineralogy. 405

cent to it will be found all that is left of the ore formation. This,
however, is not what Mr. Brooks intended in his statement, as
these detrital rocks apparently form but a small portion of his
" quartzites." These of course mark old beaches water-worn after
the jasper and ore were in situ, in nearly their present condition
and, if the logic of the geologists of the Michigan and Wisconsin
surveys were carried out, these unconformable detrital formations
would mark a new geological age. * * *

At the upper portion of the Jackson mine, Negaunee, the jas-
per and hematite were seen to cut across and obliquely up
through the schists. The jasper also curves in a similar manner
at right angles X,o this nearly east and west section. While this
could be explained easily by sedimentation, it is fatal to the view
of conformable deposition. In pit No. 3 of this mine (Jackson)
the ore breaks irregularly through the schist, forming a breccia-
ted-looking mass, while in other cases it runs up into the schist
ending in irregular knobs. * * * *

In pit No. 4 a wedge of ore and jasper was seen intruding be-
tween and across the lamination of the schist. In the u north
pit" the eruptive character of the ore is well shown. Overlying
the ore at a low angle is a quartzite containing jasper and ore
derived from its underlying ore. At the Home mine in the Cas-
cade range the ore was largely a sandstone impregnated with
hematite, strike N. 70° W. with a northerly dip, which varies
owing to the contortion of the strata from 30° to 70°. Several
dikes of jasper run through this sandstone, in part conforming to
the bending of the strata, and in part breaking across the laminae.
There is no mistaking the intrusive character of the jasper and its
interlaminated ore here. It is of course almost unnecessary to
state that this mine, having as its chief ore a ferruginous sand-
stone, was long since abandoned. The quartzite (metamorphosed
sandstone), which forms the hanging wall of the Pittsburg and
Lake Superior mine, Cascade range, has been cut through by
dikes and little stringers of nearly pure hematite which, in its
present position, is distinctly intrusive. While in general these
little dikes follow approximately the bedding, they are seen not
to exactly do this, but cut the laminae obliquely through much of
their course. This mine contains as a secondary formation much
specular iron. Near the bridge over the Palmer mine the jasper
shows well its eruptive character in its junction with the quartz-
ite, while the banding is seen to be parallel to the contact line.
This jasper holds in it, and as part of itself, the hematite mined
here.

It is advocated by Messrs. Credner and Brooks that all the iron
was originally in the state of magnetic oxide, this view being sus-
tained by the crystals of martite found in various parts of the dis-
trict.

It would seem that a microscopic examination of the banded
jasper and ore should give us some facts bearing upon the ques-
tion. A section was made of a tinely-banded jasper taken near

406 Scientific Intelligence.

the Lake Superior mine. Under a lens this shows a fine contor-
ted banding. Microscopically this section is composed of a fine
granular ^aggregate of quartz and hematite, and a more coarsely
crystallized portion made up of octahedrons of magnetite or mar-
tite, and of quartz of secondary origin. The quartz in the first
part is largely filled with minute globules and grains of ore,
which also occurs in irregular masses and in octahedrons. The
quartz associated with the more coarsely crystallized portion is
water clear, and shows the usual fibrous granular polarization of
secondary quartz. Wherever the iron is in a distinguishable
crystalline form it is in octahedrons. The color and streak of the
iron in the hand specimen are those of hematite, but the powder
is found to be magnetic. The section was taken from the most
jaspery portion, and shows much of the fine aggregation of quartz
and hematite. The structure of the quartzose portion is like the
devitrification structure of the rhyolites and felsites. The section
has been repeatedly fissured, and the fissures filled in with second-
ary deposits of quartz and octahedral crystals of iron. So far
as we have observed, the brecciated jasper and ore have had their
fractures filled in like manner. The jaspery portion is finely
banded, and shows an apparent fluidal structure. We are in-
clined to regard the structure as fluidal, but in a rock so deeply
colored it is difficult to make satisfactory examinations. This is
the only section that shows anything like a well-defined limit
between the jasper and ore bands, under the microscope, as
pointed out by Dr. Wichmann.* The powder of the two last-
described specimens is feebly magnetic. The quartz is much
fissured, showing the effect of heat, and contains microlites and
fluid and stone inclusions.

The octahedral form of the iron ore would sustain the view
that it was all originally magnetite. The difficulty lies in prov-
ing the crystals to be primary, and not secondary forms, espe-
cially as they are largely associated with secondary quartz, and
also are abundant in the little fissures (minute veins), traversing
the jasper. Our microscopic examination of rocks of various ages
and characters goes to show that all rocks, especially the older,
have been subject to more or less alteration. This alteration is
accompanied by recrystallization, which often obliterates the
original characters. This change appears to be produced through
the medium of the percolating waters, and consists rather in a
chemical rearrangement of the constituents of the rock, amongst
themselves, than in the deposition of any material brought in
from extraneous sources. The jasper and iron ores, as well as all
other rocks examined microscopically from this district, have suf-
fered this alteration to a greater or less extent ; therefore it is
perhaps impossible at present to be sure of the original state of
the iron, or how many changes have taken place.

Without objecting in any degree to the idea that the ore was
originally magnetic, certain facts indicate that the present mag-

*Geol. of Wise, iii, 615.

Geology and Mineralogy. 407

netic state of the iron is in some places due to secondary oauses ;
i. e. the heat of intrusive rocks erupted since the iron ore and jas-
per were in place. While in general the Republic Mountain ore
is hematite, exceptions exist. On the northerly side of the hill a
" diorite " dike was seen. It is found that the ore was so affected
by the heat of this intrusive mass that it is magnetic adjacent to
it, while a short distance away it is the normal hematite.
Numerous other localities were examined about the hill where
these secondary intrusions occurred, with the same result ; the iron
ore was magnetic adjacent to the dikes, but not magnetic a short
distance away. As a general rule, the magnetite or the hematite
pseudomorphs after it (martite) are found near the " quartzite " of
Brooks in this mine. Those who examine the map of Republic
Mountain, prepared by him,* will observe on the northern side ot
his " quarztite," a queer tongue of it projecting into the hematite.
An examination of this tongue at different places shows the fol-
lowing facts : It contains numerous rounded and irregular frag-
ments of the iron ore in it ; these fragments occur on both edges,
while the centre of the mass is free from them. At this point it
varies from a few inches to two feet in width, and it is seen to
break across the lamination, although nearly coinciding with it.
At another part shown near the same pit, this rock and
its contact with the "jasper" and ore were well marked. The
" quartzite " is firmly welded to the ore, and breaks across the
laminae, cutting them, and sending tongues into the mixed jasper
and ore. The junction is an eruptive (intrusive) one, and not
that belonging to the contact of one sedimentary rock with
another. The ore at the junction is magnetic. The question
whether this is an intrusive or sedimentary rock has another side
than the simple scientific one. It makes a great difference in the
mine whether this is a simple overlying metamorphosed sandstone,
as Mr. Brooks places it, or a later intrusion cutting the ore below.
This latter case opens up numerous questions that the practical
man can only disregard to his cost, sooner or later, but which
have nothing to do with the present discussion.

As this rock seems to belong to the granites, it will be
described under them. Should future research show that all of
the " quartzite " of Republic is the same as the tongue is, it
would have a bearing on the proximity of the magnetite and mar-
tite to it.

In like manner, passing to other mines where secondary intru-
sions are more abundant, the magnetite becomes a more promi-
nent feature. It seems, so far as we have seen, that the magne-
tite and martite are directly proportioned to the amount and
proximity of eruptive rocks, extravasated since the ore was in
situ. — Geol. Iron and Copper Districts, pp. 28-35.

From the " General discussion" in the last chapter, on the
Iron District. — So far as geological science has now advanced,

* Atlas, Geol. of Mich., 1869-73, Plat? VI.

408 Scientific Intelligence.

the facts observed can only be explained by the eruptive origin of
both the ore and jasper, as they make the same formation.

The ore and jasper show that they are the intrusive bodies by
their breaking across the lamination of the schists and other
rocks, by the changes that take place in the latter at the line of
junction, by horses of schist being enclosed in the ore, by the
curvature of the lamination, produced by the intrusion of the ore
and jasper, etc. Not the slightest sign of the plasticity or intru-
sion of the schists relative to the ore or jasper was seen. That
the present lamination of the schist existed prior to the intrusion
of the ore and jasper is shown by the effect of the latter upon and
its relations to it. That this lamination is the original plane of
deposition is for part of the schists not known ; but whether it is
or not, it has been taken to be such by the observers quoted in
the establishment of their theories, and they must abide by it.
The lamination, however, coincides with many of the well-strati-
fied rocks adjacent, and in some of these the ore and jasper were
unmistakably intrusive. The schists that retained well-marked
stratification planes showed in some places extraordinary contor-
tions, one specimen showing a synclinal and anticlinal fold,
requiring, were the top eroded, the counting of the same layer
four times in the width of two inches. This is only one case out
of numerous ones observed. — Ibid, p. 67.

5. Saurian and Mammals of the Lowest Eocene of New
Mexico. — Professor Cope has described in the American Natu-
ralist (August, 1881), a Saurian, Champsosaurus australis Cope,
from beds in New Mexico which lie below the typical Wasatch
Eocene, and possibly from the Puerco beds. The genus was first
described by Cope from specimens in the Laramie beds named
(J. laticollis, and has since been recognized by Dr. Lemoine, near
Reims, in the Suessonian Eocene associated with mammals.
From these same lowest Eocene beds of New Mexico Prof. Cope
has described the mammals, Mesonyx Navajovius (Creodont),
Periptychus carinidens (Creodont), Triisodon Quivirensis (Creo-
dont, which group is placed by the author between the Marsupials
and Carnivores), Deltatherium fundaminis (Creodont), Conoryctes
comma, allied to Mesonyx, Catathlceus rhabdodon, Anisonchus
sectorius, Mioclamus turgidm, M. subtrigonus, Phenacodus Puer-
eensis, Ph. Zuniensis, Protogonia subquadrata (Chalicotheriidse),
Meniscotherium Terrcerubrm. No Coryphodon remains have yet
been detected in the beds. The Suilloid genera are stated to be
characteristic.

6. Miocene Rodents of North America and Can idee of the
Loup Fork Epoch. — A review of the N. A. Miocene Rodents and
another of the Canidae of the Loup Fork Epoch is published Dy
Professor Cope in vol. vi of the Bulletin of the TJ. S. Geol. Sur-
vey under Dr. Hayden, for September, 1881.

1. The Irish Elk, Megaceros Hibernicus, in the Ancient lake
deposits of Ireland. — Mr. W. Williams, in the Geological Maga-
zine for August, describes the deposits of some of the bogs of Ire-

Geology and Mineralogy. 409

land, with reference to the position in them of bones of the Irish
Elk. Those of the Ballybetagh bay, about nine miles southeast
of Dublin, have first (1) a lining of tenacious clay resting on
bowlder clay, within this at bottom (2) a yellowish gray bed,
slightly clayey, consisting chiefly of vegetable matter; next (3),
a bed of dark brownish clay containing remains of Megaceros ;
then (4), a grayish clay about thirty inches thick, containing rock
debris from the hills ; which last is covered by peat. He states
that the bones are found only in No. 3, and that during the thirty
years past, nearly one hundred heads have been found in this
bog (almost all males), with scarcely six skeletons. The stage of
growth of the antlers — whose average weight is sixty pounds —
shows that the animals were mired at different times during the
year.

The clay No. 4 is regarded by the author as having been de-
posited during the second Glacial epoch, and the stones it contains
are attributed to the ice and frosts of that time. In this clay the
author found the antler of a Reindeer, and this is regarded as cor-
roborative of his conclusion. The broken state of the bones of the
Megaceros is attributed to the pressure of the overlying mass or
masses of ice. No human implements occur in the clay, leading
to the conclusion that "man had hardly appeared in Ireland," and
that the Megaceros was exterminated not by man, but by the
augmenting cold of the approaching Glacial era. All these infer-
ences are stated to be sustained by the facts from other Irish
bogs.

8. The Tertiary Lake Basin of Florissant, Colorado ; by S.
H. Scudder. pp. 279-300 of the Bulletin, vol. vi, No. 2, of the
U. S. Geol. and Geogr. Survey, under Dr. F. V. Hayden (Dept. of
the Interior). — Mr. Scudder describes in this paper the position,
characters, paleontology and age of the remarkable lacustrine
deposits of Florissant, Colorado, and illustrates the subject with a
map. His observations in the region were made in 1877, along
with Mr. A. Lakes, whose geological notes are incorporated, and
also Mr. F. C. Bowditch. The lake- basin, nearly nine miles long,
according to the map, occupies a low depression among the moun-
tains at the southern extremity of the Front Range of Colorado
"at no great distance from Pike's Peak," and sends its arms up
the valleys on either side. The beds are whitish, drab and
brownish shales below, with fine and coarse sandstone above;
and, besides, trachyte occurs in the adjoining promontories and
along the margin of the basin. The material of the coarser beds
directly above the shales, from a locality visited by Mr. Scudder
(south of the house of Mr. A. Hill), according to microscopic in-
vestigations by Mr. M. E. Wads worth, is tufaceous ; and the
shales are "simply the finer material of the tufas laid down in
lamina} of varying thickness and coarseness." The shales at this
place are about 22£ feet thick. The fossils from the Florissant
shales include: — of Hymei.opterous insects, several species of
Apidae and Andrenidae, about 30 of Vespidse or wasp-like Hy-
menoptera, 50 species or more of ants (mostly Fonnicidae, with

410 Scientific Intelligence.

some Myrmicidse and Poneridae) represented by about 4,000
specimens; about 80 species of Ichneumonidae, over 100 other
species of Hymenopters ; of Lepidopters perhaps a dozen species;
of Dipters, some thousands of specimens and a large number of
species, among them 1,000 specimens of Bibionidse, and "a vast
host of Muscidae and allied kinds ;" of Coleopters, over 300 spe-
cies, of the normal series, and about 120 of the Rhyncophorous
section; of Hemipters, more than 100 species of the Heteroptera,
and 65 of Homoptera; of Orthopters, many species; of Neurop-
ters, largely the Phryganidse of which there are 15 or 20 species,
6 species of the Termites family, and others ; of Spiders, 30 spe-
cies, all Araneae ; one Myriapod, an lulus ; of Mollusks, only one
species, that a Planorbis ; of Fishes, 8 species, all described by
Cope, except one by Osborn, Scott and Speir; of Birds, several
feathers, a single tolerably perfect Passerine bird, described by
J. A. Allen, under the name Paloeospiza bella, and a plover,
Charedinus Sheppardianus, described by Cope.

The fossil plants include large silicified trunks of trees proba-
bly Sequoias, and many species, 90 to 100 in all, about 40 of
which have already been described by Lesquereux, besides some
flowers with long stamens. The assemblage of plants indicates,
according to Lesquereux, a climate like that of the northern
shores of the Gulf of Mexico; of fishes, according to Cope, of lat-
itude 35° ; of insects, according to Scudder, a still warmer climate.

The age of the deposits is referred by the most recent and best
authorities to the later Eocene or early Miocene.

The insects are soon to be desbribed by Mr. Scudder in a quarto
volume and illustrated by a large number of plates.

9. Address of the President of the Geological Society of
London, Robert Etheridge, F.R.S., at the Anniversary Meeting
on the 18th of February, 1881. — The subject of this address, is
the " Analysis and Distribution of the British Paleozoic Fossils."
It is a carefully prepared and critical review of what has been
learned respecting the ancient life of Great Britain in Paleozoic
time, drawn up with details as to the species of plants and
animals in the successive formations, and as to their stratigraphical
and geographical distribution, and it has a special interest for the
American geologist, on account of the wide extent and thickness
and abundant fauna of related rocks on this side of the Atlantic.

10. Pantotheria of Marsh. — This word is incorrectly spelled
Prototheria on page 286 of this volume.

11. Occurrence of Vanadates of Lead at the Castle Dome
Mines in Arizona j by Wm, P. Blake. — The occurrence of
various vanadium minerals at different points in Arizona has
been recently described by Professor Silliman in this Journal.
Similar observations were communicated to the Mining and
Scientific Press of August 1 3, by Professor Wm. P. Blake. He
states that vanadinite occurs in considerable abundance at the
u Railroad " claim in the Castle Dome district. It forms groups
of small hexagonal prismatic crystals, generally curved and
tapering as is common in pyromorphite. It is also found in

Botany and Zoology. 411

crusts of confusedly aggregated crystals, sometimes filling cavi-
ties in decomposing ores of lead and sometimes fluor spar. The
color of the larger crystals is geuerally brown ; the smaller ones
are lighter and are of various shades of orange, yellow, and yel-
lowish-brown, the latter of a wax-like luster. Associated with
the vanadinite are possibly some rarer vanadates, not yetjidenti-
fied, wulfenite, in brilliant light-yellow crystals, and a vanadif-
erous mimetite which seems to graduate into the pure vanadinite.
Professor Blake also mentions the occurrence of beautiful crim-
son-red crystals of vanadinite from the Hamburg mine and fine
wulfenites, sometimes in octahedral crystals, from the Red Cloud
mine, the " Oakland Boys' claim," and other points in the Silver
District, Arizona.

III. Botany and Zoology.

1. Recent papers on the Marine Invertebrata of the Atlantic
coast of North America; by A. E. Verrill. — During the past
few years a much more active interest has been taken in the
marine invertebrata of our coast than ever before, and accord-
ingly there has been a rapid increase in the number of papers
published on this subject. This has been due principally to the
extensive explorations of the sea- bottom and its life, made by the
U. S. Coast Survey and the U. S. Fish Commission. The work
done by the Coast Survey was mostly in the southern waters, in
the Gulf of Mexico, Carribbean Sea, and off Florida, but in 1880,
included lines of dredging off the eastern coast of the United
States, and even to the region off George's Banks. This work,
so well begun by Pourtales, has, during the later years, been car-
ried on with great perseverance, and with remarkable success by
Mr. A. Agassiz, whose collections, made by the steamer " Blake"
are of wouderful extent and interest. Numerous reports on the
earlier of these collections have been published, during past years,
but in the following list, I include only the more recent ones.

The explorations by the U. S. Fish Commission, under the
supervision of the writer, have been mostly along the northern
coast, from Long Island Sound to Nova Scotia; and in water of
moderate depths, usually within 100 miles of the coast. But all
this region has been very fully examined, dredgings having been
made at over 1600 stations, while collections of very great extent
have been accumulated. As yet very few of the final reports on
these collections have been published, but numerous preliminary
papers, by the writer and others, have been printed. Among the
more recent papers relating to the Fish Commission collections,
in addition to those printed in this Journal, are the following :

Report on the Marine Isopoda of New England and Adjacent
Waters. By Oscar Harger. <^Report of the United States
Commission of Fish and Fisheries, Part VI, for 1878 [pp. 297-
458, 13 plates], 1880. — This is a complete monographic report on
all the species (46) known up to the date of publication, with de-
scriptions and good figures of nearly all the species. It is fol-
lowed by a bibliographical list of works on the subject.

412 Scientific Intelligence.

Report on the Pycnogonida of New England and Adjacent

Waters. By Edmund B. Wilson. <^Report of the United Statu

Commission of Fish and Fisheries, Part VJ, for 1878 [pp. 463-

504, pi. 1-7], 1880. — A monographic revision of all the species —

fifteen in number — followed by a bibliographical list.

Notice of a new Species \Polycheles sculpt as] of the " Witte-
moesia Group of Crustacea" {Recent Eryontido?). ^Proceedings
U. S. National Museum, vol. ii, for 1879, [pp. 345-353, pi. 7],
March, 1880. By Sidney I. Smith.

Preliminary notice of the Crustacea dredged in 64 to 325
fathoms, off the south Coast of New England, by the United
States Fish Commission in 1880. By S. I. $>mm.<^Froceeding*
U. S. National Museum, vol. iii, for 1880, [pp. 413-452], January,
1881. — Contains a general list of fifty species, with their geo-
graphical distribution and descriptions of numerous new species
and one new genus (Hemipagurus).

Notice of Recent Additions to the marine Invertebrata of the
northeastern coast of America with descriptions of netc 'genera
and species and critical remarks on others. ^Proceedings of
the United States National Museum, vol. iii, Dec., 1880, and
Jan., 1881.

Part IT. — Mollusca, with Notes on Annelida, Echinodermata,
etc., collected by the U. S. Fish Commission [pp. 356-405], Dec.,
1880 and Jan., 1881.

Part III. — Catalogue of Mollusca recently added to the Fauna
of Southern New England [pp. 405-409]. By A. E. Verrill.

The Cephalopods of the Northeastern Coast of America. By
A. E. Verrill. Part II. — The smaller Cephalopods, including
the "Squids" and Octopi, with other allied forms. <^Trans.
Conn. Acad., v, [pp. 259-424 (unfinished), pi. 26-56], June,
1880, to Oct., 1881. — Although this paper is all in type, a few of
the last signatures are not yet issued. It is a monographic
revision, with descriptions and figures of all the species. A con-
siderable amount of anatomical work is also introduced. Most of
the species have already been noticed by me, in different articles,
in this Journal. Among those not previously described are
Chiroteuthis lacertosa, Brachioteuthis JBeanii, gen. et sp. nov.,
Rossia megaptera. Brachioteuthis is a deep-sea genus, allied to
Chiroteuthis, but having simple connective cartilages on the
siphon and mantle. A new genus (Stoloteuthis) has also been
established for Sepiola leucoptera V. It is remarkable for having
free eye-lids, round pupils, arms webbed, and no pen. Inioteuthu
is established for Sepiola Janonica ; it differs from Sepiola in
lacking a pen. A second Japanese species has four rows of
suckers (I. Morsei).

New England Annelida. Part I, Historical Sketch, with An-
noted Lists of the Species hitherto Recorded. By A. E. Verrill
<^Trans. Conn. Acad., iv (pp. 285-324], 1881. — In connection
with the annotation, a considerable number of changes in nomen-
clature are introduced, and a few new genera are established.
These are Euglycera for Glycera dibranchiata Ehlers ; Dipoly-

Botany and Zoology. 418

dora9 for Polydora concharum V. ; Praxillella for Praxilla (pre-
occupied). The several species hitherto referred to Anthostoma
are referred to Scoloplos.

The following papers relate to the collections made by Mr.
Agassiz, on the " Blake :"

Reports on the Results of Dredging, under the supervision of
Alexander Agassiz, by the United States Coast Survey Steamer
"Blake." Bulletin of the Museum of Comparative Zoology,
Vols, viii, ix.

VIII, — Etudes prelim ina ires surles Crustaces. Par A. Milne-
Edwards. 7er Partie, viii, [pp. 1-68, 2 pi.], Dec. 29, 1880.—
Contains brief descriptions of a large number of new genera and
species of Decapoda. Many of them can scarcely be identified
without figures.

IX. — Preliminary Report on the Echini, By A. Agassiz.
Vol. viii, [pp. 69-84], Dec, 1880. — Enumerates 45* species, of
which manv are described as new.

X. — Report on the Cephalopods, and on some additional
species dredged by the United States Fish Commission Steamer
"Msh Hawk" during the season of 1880. By A. E. Verrill.
Vol. viii, [pp. 99-116, 8 plates], March, 1881. — This includes
descriptions of two new species, viz : Mastigoteuthis Agassizii,
gen. et sp. nov., Eledone verrucosa. Figures and descriptions are
also given of Chiroteuthis Bonplandi ? [= C. lacertosa v., 1881],
Rossia sublevis, Heteroteuthis tenera, Octopus Bairdii, O. lentus,
Cheloteuthis rapax V. [=Lestoteuthis Fabricii V. [=Gonatus
Fabricii Steenst.], Calliteuthis reversa, Alloposus mollis.

XI — Report on the Ac<dephm. By J. VV. Fewkes. Vol. viii,
[pp. 127-140, 4 plates], March, 1881. — Contains descriptions of
several new species of Plumularidce, Sertularella, Lafoea, and of
a new genus, Aglaophenopsis.

XIII — Report on the Pycnogonidn. By E. B. Wilson.
Vol. viii, [pp. 239-256, 5 plates], March, 1881. — Ten species are
recorded. One genus and five species are new. The new species
belong to Colossendeis, Scceorhynchus (nov.), and Pallenopsis
(nov.) Some of the species of Colossendeis are of great size
(extent, 343nim).

XV. — Preliminary Report on the Molhtsca. By W. H. Dall.
Vol. ix, [signatures 3-6, pp. 33-96, unfinished], July to September,
1881. — A large number of new species and several new genera
are described in the four signatures received. Among the genera
treated are Cadulus, Dentalium, Siliquaria, Pedicularia, Margarita,
Calliostoma, Seguenzia, Basilissa, Septothyra, Callogaza, nov.,
Microgaza, nov., Fluxina, nov., Hanleyia, Pleurotoma and its
subdivisions, Trichotropis, Marginella, Puncturella, Pleurotoma-
ria, Haliotis, Crepidula, Trifori:*, Cerithiopsis, Bittium, Colum-
bella, Natica, Turritella, Action.

XVI — Preliminary Report on the Comatulw. By P. Her-
bert Carpenter. Vol. ix, [20 pp. 1 pi.], Oct. I, 1881. — The
author states that he now recognizes about 55 species of this
group from the Caribbean Sea and West Indies. They belong

414 Scientific Intelligence.

mostly to the genera Actinometra and Antedon. Of these the
former is the more abundant, both in species and individuals. In
this paper a few new species of these genera are described, and
two species of a new genus, Atelecrinus. The "Blake" collec-
tion is contrasted with that of the " Challenger."

Various other papers, not relating particularly to the two ex-
plorations referred to above, have been recently published.
Among these are the following :

The Stomach and Genital Organs of Astrophytidce. By T.
Lyman. <^Bull. Mus. Comp. Zoology , viii, [pp. 117-126, 2 plates,]
Feb., 1881.

Studies of the Jelly-Fishes of Narragansett Bay. By J. W.
Fbwkks.k^BuII. Mus. Comp. Zoology, viii, [pp. 141-182, 10 pi.].
— This includes many details concerning several known species
and the following new forms : Mabella gracilis, gen. and sp. nov.,
Modeeria multitentacula, Dinematella cavosa, gen. and sp. nov.,
Eutima gracilis, Sphaerula formosa, gen. and sp. nov., Cunina
discoides.

II. — The Siphonophores. The Anatomy and Development of
Agalma (continued). By J. Walter Fewkes. ^American
Naturalist [pp. 186-195], March, 1881.

On some Points in the Structure of the Embryonic Zoea. By
Walter Faxon. <2Jm& Mus* Comp. Zoology, vi, [pp. 159-166,
2 plates], Oct., 1880. — Relates to the development of Carcinus
and Panopeus.

On some Crustacean Deformities. By W. Faxon. <^2?w#.
Mus. Comp. Zoology, viii, [pp. 257-274, 2 plates.] — Discusses
numerous deformities of Homarus and Callinectes:

The Development of the Squid, Loligo Pealii (Lesueuer). By
W. K. Brooks. ^Anniversary Memoirs of the Boston Society of
Natural Historv, 1880.

Annelida Chcetopoda of New Jersey. By H. E. Webster.
<^Thirty-second Annual Report on the New York State Museum
of Natural History, [pp. 1-28, plates not issued] 1880, (dated
1879). — Although put in type in 1879, this paper was not actually
published until 1880, and the plates that were prepared for it
have not yet been published. A number of new species are
described belonging to the genera Anaitis, Eteone, Podarke, Gru-
bea, Goniada, Polydora, Streblospio (gen. nov.), Praxilla, Parax-
iothea (gen. nov.), Sabellides. Fifty-nine species are enumerated.

2. A Manual of Practical Normal Histology ; by T. Mitch-
ell Prudden, M.D. (New York: G. P. Putnam's Sons, 1881.)
pp. viii and 265, small 8vo. — The method of giving a brief de-
scription of the tissues and organs in appropriate sequence, and
following each description with an account of the way in which
the structures described may be demonstrated has been admirably
carried out in this modest little volume, which well fills an
unoccupied place among elementary text books. In no other
English text book certainly can be found so concise and clear an
account of the structure of the principal animal tissues, as at present
understood. The directions for demonstration are sufficiently

Astronomy. 415

simple and clear to be readily followed, even without an instruc-
tor, by any intelligent student familiar with the use of the micro-
scope, s. i. s.

3. XT. S. Entomological Commission , Department of the Inte-
rior. Index volume to Dr. Riley's Missouri Reports on Insects. —
Bulletin No. 6 of this Commission, numbering 178 pages, 8vo,
consists of a General Index and Supplement to the Nine Reports
by Charles V. Riley, M.A., Ph.D., on the Insects of Missouri.
The importance of these reports, economically and scientifically,
makes this Index volume one of much value. It is intended to
stand as vol. x of the series. To increase the value of the vol-
ume, the author has brought together the tables of ^contents of
the nine volumes, with errata, and has also reproduced the de-
scriptions of new species, added a list of descriptions of adolescent
states, of descriptions of species not new, of food plants, and of
illustrations.

4. The Hessian Fly, its ravages, habits, \ enemies, and the
means of preventing its increase, by Dr. A. S. Packard, is the
subject of Bulletin No. 4. It is illustrated by a map and two
plates,

5. E. S. Morse on changes in My a and Lunatia. — Professor
Morse has sent the following correction for his note on page 323
of this volume: "A comparison of the common beach cockle
Lunatia showed that the present form living on the shore to-day
had a more depressed spire than the ancient form."

IV. Astronomy.

1. Theory of the Moon's Motion, deduced from the Law of
Universal Gravitation ; by John N. Stockwell, Ph.D. Phil-
adelphia, 1881. (J. B. Lippincott & Co.) — Although the motion of
the moon around the earth has been the subject of profound
study, during the past two hundred years, and has been the occa-
sion of more elaborate mathematical investigations than all the
other members of the solar system together, the tables of the
moon's motion which are based on these calculations fail to repre-
sent the moon's place in the heavens with a precision at all com-
mensurate with the labor bestowed upon the lunar theory. As a
matter of fact the latest tables of the moon scarcely represent the
observations with greater precision than those in use at the begin-
ning of the present century. In view of this fact, the author of
this work several years since called the attention of astronomers
to the great apparent errors of the lunar theory, and expressed
the belief that the theory itself must be in error by terms of the
third order of magnitude in the perturbations, instead of being
correct to terms of the seventh order, as had been hitherto sup-
posed.

In order to satisfy himself of the correctness of this conclusion,
he undertook, some six years ago, a complete and systematic
development of the lunar theory, according to a method different
from any that had been before applied to the problem. The

416 Astronomy.

application of this method to the motion of the moon constitutes
the principal, or strictly technical part of the work ; while the
history of the problem and the comparison of the results obtained,
with the corresponding results of other calculators, is given in
considerable detail in the introduction.

The author believes that he has discovered i wo equations of
the third order of magnitude having a short period, besides other
terms of long period depending on the sun's action and on the
oblateness of the earth, which have not been before correctly
computed, and which are of very considerable importance in the
lunar theory. Should these results be confirmed by other calcula-
tors, the remark of the late Astronomer Royal, Sir G. B. Airy,
made some eight years ago, namely : " that there is some serious
defect in the lunar theory," will be fully justified.

This is the first book published in this country, which is wholly
devoted to the mathematical development of the general theory
of the moon's motion, as affected by the sun's attraction ; although
important papers have been published at different times in the
various scientific journals of the country, upon some particular
cases of lunar perturbation due to the sun's action. The problem,
though old, is still one of the most interesting and important in
celestial mechanics ; and it is to be hoped that other American
mathematicians will interest themselves in its solution.

The book contains about four hundred pages, and in this
respect contrasts happily with the great works of Plana and
Delaunay, which, taken together, cove.* considerably more than
four thousand pages.

It is printed in handsome style, on excellent paper. Aside from
the intrinsic importance of the subject of which it treats, it fur- •
nishes a multitude of beautiful solutions of problems which are
always of interest to the student of the pure mathematics; and
we cordially commend it as worthy of a place in all the scientific
libraries of the country, whether public or private.

2. Astronomical and Meteorological Observations made during
the year 1876 at the U. S. JV. Observatory. Rear-Admiral C. H.
Davis, Superintendent. Government Printing Office, 1880. — This
contribution of the Naval Observatory to science fills two thick
quarto volumes, one containing the regular observations and the
other made up of three important appendices. The first appendix
is a subject index (of 74 pages) prepared by Prof. Holden, to all
the publications of the U. S. N. Observatory. It makes the valu-
able material that is scattered through these volumes far more
easily accessible than heretofore to astronomers. The second
appendix (of 126 pages) contains the several reports on the transit
of Mercury, in May, 1878. The third appendix, on the solar
eclipse of July, 1878, has been already noticed (this Journal, III,
vol. xxi, p. 334). h. A. N.

OBITUARY.

Dr. G. Linnarsson, paleontologist of the Geological Survey
of Sweden, died recently at the age of forty years.

THE

AMERICAN JOURNAL OF SCIENCE.

[THIRD SERIES.]

-••-*-

.Art. LIV. — On a possible cause of the Variations observed in
the amount of Oxygen in the Air ; by Edward W. Morley,
M.D., Ph.D., Hurlbut Professor of Chemistry, Western
Reserve College, Hudson, Ohio.

In order to determine, if possible, whether the observed va-
riations in the proportion of oxygen contained in the atmos-
phere at different times is occasioned by the descent of air from
an elevation above the surface of the earth, I have made two
series of analyses in duplicate of samples taken each day at
this place. The results are given in the accompanying table.

Theresults for the first period have been compared graph-
ically with the indications of the thermometer and barometer
furnished me by the Signal Service observer at Cleveland. At
times, when the meteorological conditions of the region were
simple enough, it was easy to see that the deficiencies in the
proportion 01 oxygen followed closely times of high barometer
and low temperature, when, if ever, it would be fair to infer
that the descent of air from an elevation would take place.
But in a great number of cases it is impossible to infer very
much as to the atmospheric currents of the region from obser-
vations at one place.

But if we examine the thrice-daily maps of the state of the
thermometer, barometer and winds, as observed by the Signal
Service, we may obtain reasonably good evidence as to the
atmospheric currents of this region at the times of deficiency of
oxygen observed. When we find this place at or near a cen-
ter of high pressure, and find the recorded directions of the

Am. Jour. Soi. — Third Series. Vol. XXII. No. 132. — December, 1881.

418 E. W. Morley — Cause of the Variations

sfiS3si~"

It!

:,?, ;;iE-;,S: jz.-,

Observed in the amount of Oxygen in the Air, 419

Oxygen found in the Air at Hudson, Ohio, from January to April, 1881.

January,

1881.
gen.

939

February.

March

•

\prll.

Date.

Oxy
949

Date.
1

Oxygen.

Date.
1

j Oxygen.
948 953

Date.
1

Oxygen.

958

961

972 972

936

940

959

953

1950

956

974 975

954

960

954

960

967

965 964

952

94T

952

962

(961

962

4 967 968

959

957

964

959

962

969

5 '970 973

954

951

949

962

958

962

972 974

958

963

963 l
966 j"

969

973 968

956

953

966

964

962

8 962 972

958

948

968

965

963

9 1962 966

946

960

959

956

955

962

10 967 971

954

962

951

950

967

966

963 971

966

967

950

946

948

959

966 967

957

959

963

961

958

13 !963 969

963

956

953

951

962

964

973 971

958

957

948

957

962

965

975 970

957

961

958

962

969

964

16 968 970

960

961

951

960

963

970 966

952

961

967

972

965

969

959

957

955

962

1912

960

19 964 960

950

952

959

961

956

954

969 963

956

957

954

974

958

960

961

968

957

948

950

954

970

938

933

968

962

970

967

955

947

963

972

967

969

959

958

959

961

960

962

952

947

958

959

962

963

969

967

958

976

977

959

943

950

952

955

953

961

957

959

960

954

973

972

968

964

960

962

The figures in the column ** Oxygen" are the 3d, 4th and 5th decimal places:
before which are to be supplied the decimal point, followed by the figures 20.
For example, 956 signifies 0*20956. Hut on March 9, 1880, supply 02 1. 18, col-
lected at noon ; \ 9, 8, 4, 8, 8, 9, collected at 1,2, 3, 4, 5, 8, 9, p. m. ; •, second sam-
ple collected nearly ut the same time as the preceding sample.

winds at the stations of the Service all radiating from this center,
especially if their velocities are considerable, we may infer with
some fair probability that within this area of radiation there
was a descent of air from an elevation.

I have, therefore, examined the Signal Service maps of the
date of each deficiency in oxygen, or of each noteworthy fall in
the amount of oxygen. The reproducing a score of these maps
here would facilitate the forming an opinion as to the sound-
ness of my hypothesis ; but since the morning maps are easily
accessible to most of those who would be interested in this

420 E. W. Morley — Cause of Hie Variations

paper, and at no very long time after their date, I think it suffi-
cient to describe what I learn from the examination, and to
refer to the maps themselves those who may desire to form an
independent opinion. Meanwhile I give, necessarily somewhat
in detail, an account of the indications gained from ray own
comparison of the maps with the results of the analyses.

The analyses here tabulated have been made with the im-
proved apparatus alluded to in a former article in this Journal
as intended to lessen the probable error of an analysis. A
comparison of the duplicate analyses made on the same sample
will show that this intention has been carried out.

Jan. 9, 1880, 7 A. M. — There was an area of low pressure
over the western part of Illinois, and of high pressure over the
Gulf of St. Lawrence. The isobar of 30*10 inches ran from
Montreal along the Appalachians to the Gulf of Mexico. East
of the Appalachians, from Albany to near Knoxville, there
were gentle winds of three or four miles an hour. They were
not so directed as to indicate any general current across the
mountains. West of the mountains there were brisk winds of
eight miles an hour at Columbus, Cincinnati and Indianapolis,
of nine miles at Pittsburgh, of ten miles at Buffalo and Louis-
ville, and of from fifteen to twenty miles at Cleveland, Toledo
and Erie. All these were nearly transverse to the axis of the
Appalachians. A study of the weather map of this date sug-
gests as a probable view that the mass of air passing to the north-
west over Ohio was not part of a current passing at the surface
of the earth over the Appalachians, but that it was in part the
result of a descent of some upper current to the surface of the
earth. Similar conditions continued at 3 P. M. At 2 P. M. the
oxygen in the atmosphere at this place was 0*20936. It had
been low on the preceding day, but observations of the wind
and barometer were insufficient to determine the direction of
the great currents of the air.

Jan. 10, 7 A. M. — There was an area of high barometer hav-
ing its center over southwestern Ohio. From a little to the
northwest of this center, winds were distinctly radiating in
every direction with a velocity of about five miles an hour. It
is therefore probable that the central area of high barometer
was kept supplied by some current of air from an elevation.
At 8 P. M. the center of radiating winds had moved so as to be
over Lake Ontario. Cleveland was on the curve of 30*30
inches pressure. No winds were entering this curve at the sur-
face of the earth as far as we can learn from the weather map
of this hour, while they were moving outward all around it
with a mean velocity of several miles an hour. The high pres-
sure was not materially decreased bv this outflow, and this
continuance of high pressure was not due to rise of tempera-

Observed in the amount of Oxygen in the Air. 421

ture for the region had become colder. It is, therefore, highly
probable that some current of air from an elevation entered the
area ; and at 4 P. M. the oxygen found here was 020945.

Jan. 18, 3 P. M. — From the directions of the winds on the
map of this date we could not be sure that the currents of air
passing over Ohio had not come from the Gulf of Mexico after
passing around a center of high pressure. But the maps for
forty hours previously make it reasonably sure that no currents
at the surface of the earth had brought air from the Gulf of
Mexico to the vicinity of Cleveland, and so lead us to infer that
the sample collected here at 4 P. M. was from air spreading out
in all directions from the center of high pressure just men-
tioned, which was over the States of Mississippi and Tennessee.
It contained 0*20939 oxygen.

The deficiency of oxygen found on January 21st is consis-
tent with the theory proposed, but affords no evidence.

Jan. 26, 7 A. M. — There*was an area of high barometer over
the seaboard from Virginia to Maine. Over the southern part
of Pennsylvania there was an obvious center of winds radiating
in all directions with a mean velocity of about five miles an
hour. It is probable that the withdrawal of air from this area
was made good by the entrance into it of air from some upper
current At 9 a. m. the amount of oxygen in the air at this
place was 0*20931.

Jan. 29, 3 P. m. — At this time there was an area of high
barometer having its center a little to the northwest of Mon-
treal. The same point seems also to have been a center from
which winds radiated in every direction. Although there are
no stations reporting from the northern half of the supposed
circle, a circular course of isobars is clearly indicated; the
winds to the east of the center blow to the east, and those to
the west of the center blow due west. The mean velocity of
winds passing out from the southern half of the assumed circle
is ten or twelve miles an hour. If, then, there was a closed
curve to the north, where the air was also passing out, there
must have been a rather rapid supply of air brought into this
area by currents from an elevation, and at 9 a. m. the oxygen
found at this place was 0*20926.

Feb. 9, 7 A. M. — There was at this time an area of high ba-
rometer within which the isobar of 3040 inches was nearlv'a
circle having Lake Michigan for its center. Stations are but
few to the north and northwest of this circle, so that it'cannot
be absolutely affirmed that winds wene blowing ouiward all
around the circumference. But the gentleness of the winds
over the northern half of the circle, and the briskness of winds
passing over its southern semi-circumference, point to a descent
of upper currents. The oxygen found here at 9 A. M. was
0-20914.

422 M W. Morley — Cause of the Variations

Feb. 10, 7 A. M. — High pressure now prevailed off the coast
of New England. The form of the isobars and the directions
of the winds reported show a gentle current of air along the
eastern slope of the Appalachians, but n<> motion across them.
The crowding together of isobars running along the axis of the
mountains, as well as the uniform northwest motion of the
winds over an area reaching from Cincinnati to Oswego and
Kingston, make it probable that air from an upper current
came down to the surface of the earth near lake Erie ; and the
oxygen found here at 9 A. M. was 0*20929.

Feb. 11, 7 A. M. — At this hour there was an area of high ba-
rometer over Chesapeake Bay. The winds were all moving
away from the Appalachians, both on the eastern and the western
slopes. It is therefore likely that there was a descent of air
from some upper current. The oxygen found here at 9 A. M.
was 0-20942.

Feb. 12, 7 A. M. — There was now an area of high barometer
off the coast of South Carolina. East of the Appalachians most
of the winds were parallel to the axis of the chain. West of
the mountains the winds may well enough have come from the
Gulf of Mexico, but the acceleration of the winds as we look
toward the center of low pressure near the upper lakes may
perhaps indicate a descent of upper currents. The oxygen
found at 9 a. m. was 0*20934.

On Feb. 13th the oxygen found was 0*20897 ; this case needs
special discussion.

Feb. 20, at 7 A. M. — There was an area of high pressure hav-
ing its center near Pittsburgh. Winds radiated in all direc-
tions from this center. The inference of the descent of upper
currents is probable. At 9 A. M. the amount of oxygen found
here was 0*20930, and in another sample taken at nearly the
same time, 0*20925.

At the two hours of observation next following the one just
mentioned, the same divergence of winds from a center seems
to have continued, the center passing slowly to the east Now
at 7 A. M. on the 21st, no such condition of radiating winds
continued, but the oxygen found at 9 A. M. was 0*20926. Pos-
sibly the long continuance of conditions favoring the descent
of upper currents had brought to the surface of the earth near
this place a volume of air poor in oxygen which had not yet
been carried away under succeeding conditions.

February 22d. — At 7 A. m. there was an area of high bar-
ometer a little to the south of the Ohio River. At 9 A. M.
the oxygen found here was 0*20934, and in another sample
0*20913.

A deficiency of oxygen was also observed on February 26th,
and on March 11th, 12th and 15th, but I am able to suggest no
satisfactory explanation of either case.

Observed in the amount of Oxygen in the Air. 423

March 24th. — At 7 A. m. there was an area of high pressure
having its center at Lake Superior. Winds were diverging all
around the southern half of a circle; no stations were far
enough to the north to give any certain knowledge as to their
direction over the northern half. The oxygen found here at 9
A. m. was 0-20942.

The same remark may be made as to March 30th. A center
of high pressure existed near Lake Superior, and the winds
radiated from the southern half of a circle. The oxygen found
at 9 A. m. was 0 20922.

# April 9th. — At 7 a. m. there was an area of high barometer
reaching from Texas to Tennessee. North of latitude 37 de-
grees, and east of St. Louis, almost every reported wind was
blowing toward the north or northeast, while on the south of
the same line the winds reported were all blowing toward the
south or southwest. We may therefore suppose that some de-
scent of upper currents would occur ; at 9 a. m. the oxygen in
the air here was 0*20940.

April 14th. — At 7 A. M. there was a center of high pressure
off the coast of Georgia, but the data are too incomplete for
trustworthy inference. The oxygen found at 9 A. M. was
0*20945. On the 16th, the data are also too incomplete.

April 28th. — At 1 a. m. there was an area of high pressure
with distinctly radiating winds having their center on the Ohio
River. At 7 A. M. this center was over West Virginia. At 9
A. m. the oxygen found in the air here was 0*20957, which was a
fall of 0*00012. The cause continued to operate for some time
afterwards, and on the next day the oxygen found was 0*20941.
On the 30th, in spite of the passage of an area of low barome-
ter the oxygen continued low, being found to be 020943. On
May 1st there was a center of radiating winds over the south-
east part of Kentucky. Under the influence of the descent of
upper air which probably occurred, the oxygen found at 9 A. M.
was 0*20947.

On the 2d this center of radiating winds was over North
Carolina, and the oxygen found here was 0*20932 at 9 A. m.

On the 9th and 10th an area of high barometer hovered over
the sea coast of North Carolina for twenty -four hours, with
well marked diverging winds over the observed half of the cir-
cumference of a circle. On the 9th the oxygen found here was
0*20944, and on the 10th it was 0*20950, both at 9 A. M. An
area of high pressure now developed near Lake Michigan and
hovered to the north of the lower lakes till the morning of the
16th, when it passed over the lakes toward South Carolina.
During these days the oxygen found here at 9 A. M. was
0*20950, 0*20953, 0*20951, 0*20951, and 0*20948, and on the
16th when the area of high pressure became central near Cleve-
land, the oxygen found at 9 a. m. was 0.20927.

424 E. W. Morley — Cause of the Variations

I cannot suggest an explanation of the deficiency in oxygen
which occurred May 21st and 22d.

May 26th. — At 7 A. M. there wns an area of high pressure
over Georgia, with winds spreading in all directions around the
landward side of a circle. At 9 a. M. the oxygen found was
0-20919.

June 17th. — At 7 A. M. there was a large area of slight ex-
cess of pressure covering most of the Northwestern States. On
the 18th at 7 A. M. the high pressure had moved to the east,
and the highest pressure observed was at Cleveland. Under
its influence, the amount of oxygen found at 9 a. m. was
0-20933.

The deficiency of oxygen observed on June 28th I am not
able to explain ; the data being insufficient.

Having made my application too late, I have not obtained a
series of the thrice-daily weather maps for comparison with my
observations on variations in amount of oxygen for a period of
six and two-thirds months beginning with October, 1880. A
comparison of my observations with the daily morning maps
leaves some facts unexplained which the possession of fuller
data might clear up satisfactorily. All the maps used being of
the seven o'clock series, it will not be needful to specify the
hour further; the observations of oxygen were all made at
the same time with the observations from which the maps were
made.

I cannot explain the deficiency of oxygen occurring on
October 4th.

On October 5th there was a long narrow area of high pres-
sure reaching from New England to Texas. The spreading
out of the air on each side of this area was well marked, the
inference that there was a descent of upper currents to the
surface is well sustained, and the oxygen found was 0*20952.

October 7th. An area of high pressure had its center near
Lake Erie, with winds spreading outward in all directions.
The oxygen found was 0*20952, a fall of 0*00010.

October 10th. — A long narrow area of high pressure extended
from Maine to Texas. The radiation of winds in all directions
was decided, and the inference that downward currents min-
gled the surface air with air from an elevation reasonably prob-
able. The oxygen found here was 0*20953. But this was a
fall of only 0*00007, which is a pretty small difference. The
probability that there really was a fall in the amount of oxygen
is only about six to one.

The deficiency of oxygen on October 22d I cannot explain.

On the 25th, winds were radiating in all directions from an
area of high pressure in Eastern Tennessee. The oxygen
found was 0*20950, a fall of 0*00017 from the previous day.

Observed in the amount of Oxygen in the Air. 425

The chances that there was really a fall are here about 8000
to 1.

October 27. — There was an area of high barometer with its
center well to the north near Lake Superior. Over the ob-
served half circumference of a circle, the winds were distinctly
spreading in all directions. The inference that there were
downward currents of air is also supported by the fact of an ap-
parent excess of velocity in the winds passing south over the
lakes over the velocity of winds approaching them from the
north. Under the influence of this or some other cause, the
oxygen found here was 0*20869.

I cannot explain the deficiency of oxygen on October 30th.

On November 2d there was an area of high pressure with its
center over Tennessee and North Carolina. In a general way,
winds diverged from Kentucky and West Virginia. But there
were counter currents, so that with the materials at hand we
are not authorized to say that a descent of upper currents is
indicated with any such probability as to explain the deficiency
of oxygen found. The amount was 0*20950.

November 7th. — There was an area of high pressure with its
center over Mississippi. From this winds diverged all around
the northern half of a circle. There were some local winds in
Upper Lake Region which did not conform to this system ; but
the shape of the isobars makes it fairly probable that in the
region of the lower lakes there were descending currents of air
from the upper part of the atmosphere. The oxygen found
was 0-20951, a fall of 0*00020 since the day before.

November 18th. — There was an area of high pressure over
the Indian Territory. From this area winds were spreading
outward over the observed half circle of stations. An accel-
eration of the winds in the Lower Lake Eegions suggests a
supply of air from above to feed these winds. On the 19th
this area of high pressure had its center in Southern Ohio.
The inference of a descent of upper currents is as clear as it can
be from maps with no more reporting points than those now
established. The oxygen found was 0*20958, a fall of 0*00010
since the 17th. On the 18th it had been 0*20954.

On November 23d there was an area of high pressure with
its center over Southern Ohio, and the inference that upper
currents reinforced the winds which spread out all around this
area is a probable one. The oxygen found was 0*20951, a fall
of 0*00012 from the preceding day.

December 3. — At this time there was an area of high press-
ure with its center over Southern Ohio. It had moved with
great velocity from over the Upper Missouri Region; winds
were diverging from a center over Southwestern Ohio. The
oxygen found was not affected. On the 4th the area of high

426 E. W. Morley — Cause of the Variations

barometer was central over Chesapeake Bay, and the winds
blowing toward the northwest from the Appalachian Moun-
tains seemed not to blow over them from the east. The oxy-
gen now found was 0*20960, which was a fall of 0*00012 from
the preceding day.

The deficiency of oxygen on the 8th I cannot explain satis-
factorily.

On December 14th there was a high barometer off the coast
of Florida. As often happens, the Appalachians seemed to act as
a barrier. The winds blowing from them toward the northwest
had nothing to do with the winds to the east of the mountains.
If we may thence infer a descent of upper currents in this re-
gion, we shall account for the fall in the amount of oxygen,
which amounted to 0*00010.

The deficiency in oxygen noticed the next day is easily ex-
plained according to the working hypothesis suggested, but
does not add to the evidence for it. The same is true of the
deficiencv observed on the 19th.

On December 23d, a very wide area of high pressure with
winds diverging from the area affords a reasonable presump-
tion that these winds were reinforced by a descent of upper
currents. The oxygen found was 0*20958, a fall of 0*00006,
which is too small for safe deduction. On the 24th and 25th
the center of high pressure was nearly stationary over the lower
St. Lawrencp. The directions of the winds are rather confused,
but distinctly exhibit the tendency according to which winds
radiating from a common center of high pressure are likely to
be accompanied by a deficiency of oxygen. The oxygen found
was 0*20951 and 0*20945 respectively on the two days.

The rapid fall in the amount of oxygen on the 28th affords
no evidence for or against the theory.

The deficiency of oxygen on December 31st and January
1st was probably due to the occurrence of an area of high
pressure over the Appalachian Mountains on each of those days.
From each side of this area winds were blowing outward. The
amount of oxygen on the 31st was 0*20951 ; on the 1st it was
0*20944 in the morning, and 0*20938 in the evening. From
the weather map of the 2d, according to my theory it would
be expected that there would be a deficiency of oxygen ; but
while the evening observation showed a slight deficiency, the
morning observation showed none.

The map for the 22d gives reports from but a few stations,
so that the data are too few for trustworthy inference. As far
as the facts go, they seem little conformed to the theory.

January 25th. — At this date there was an area of high press-
ure over Mississippi. Winds were spreading outward in all
directions around this area, the oxygen found was 0*20949.

Observed in the amount of Oxygen in the Air. 427

The deficiency of oxygen noticed on the 28th was well ex-
plained by the occurrence of an area of high pressure over
Missouri, with winds radiating around it On the 29th, this area
was central over eastern Tennessee, the winds well exhibited
the spreading out in all directions which suggests the descent
of upper currents. The oxygen found on these days was
0*20957, a fall of 0*00011 as compared with the 26th.

The morning of February 9th affords a reasonably clear proof
that the surface winds implied the descent of upper currents.
There, was an area of low pressure over the mouth of the Mis-
sissippi, and one of high pressure on the northern half of the
Atlantic seaboard. East of the Appalachians, no winds were
directed across the mountains, while on the western side of the
mountains, from Louisville to Montreal, the winds were all ra-
diating from a center in Pennsylvania, with a mean velocity of
eight miles an hour. On the next day the stations near Louis-
ville were involved in currents coming from the gulf, and gen-
tle winds were blowing from the seaboard toward the Appala-
chians. There was an area of low pressure in Michigan. The
obvious acceleration of the winds in the lower lake region sug-
gests a continuance of the descent of upper currents which
probably occurred on the 9th. The oxygen observed on these
days was 0-20958 and 0*20951, against 0*20967 on the 8th.
The deficiency of oxygen continued till the 11th, with an area
of high pressure reaching from eastern Pennsylvania over the
lake region to the northwest. The oxygen now observed fell
to 0*20948.

There was a deficiency of oxygen on the 13th. There was
a general brisk motion of winds toward a center of low press-
ure in Maine, with nothing explaining the observed deficiency.

On the 15th, there was an area of high pressure with Us
center over New Jersey. Winds blew away from this center in
every direction. No deficiency of oxygen was observed, how-
ever, on the morning of this day, but on the next day the
oxygen found was 0*20951, a fall of 0*00009. Nothing on the
maps of this morning explains this deficiency.

On February 21st, there was an area of high barometer over
the lower Mississippi valley. Winds were blowing outward
in all directions. The inference that there was a descent of up-
per currents is perhaps a fairly probable one. The oxygen was
not affected at this place, being found to be 0*20964. On the
22d there was an area of low pressure over Lake Superior, tow-
ard which winds were drawn with increasing velocity from the
northwest slope of the Appalachians, while on the other side
of the mountains the winds show no connection with the sys-
tem prevailing on the northwest side. Over the region from
Louisville to Kingston the mean velocity of the winds was

428 K W. Aforley — Oxygen in the Air.

eleven miles an hour. It seems almost certain that there must
have been a descent of upper currents. The oxygen found on
this morning was 0*20952, a fall of 0*00012.

On February 28th, the oxygen here fell to 0*20947, but
there is nothing in the map of that date suggesting any expla-
nation. On the previous day, however, there were such condi-
tions as seem to indicate that a deficiency of oxygen was to be
expected. If from other evidence my theory should seem to
be a first approximation to some law of nature, it will be sup-
posed that some air deficient in oxygen, brought to the surface
of the earth by the conditions prevailing on the 27th, came to
the observer here on th§ next day. But this is almost too pre-
carious to be mentioned.

On March 1st and 2d, there was an area of high pressure over
Lake Superior, with winds radiating around the observed third
part of a circle. The oxygen found on these days was 0*20951
and 0*20953. On the 3d, there was an area of low pressure
and a storm of considerable violence over the Ohio valley, and
the oxygen found promptly went up to 020967.

On March 12th, there was an area of relatively high pressure
over Lake Ontario, with a storm having its center of low press-
ure in Kansas. Winds were directed away from Lake Ontario
in all directions, the inference that there occurred a descent of
upper currents is a reasonable one, and the oxygen found was
0*20954, a fall of 0*00012.

• March 19th. — At this time there was an area of high pressure
in Maine, and of low pressure over western Kentucky. The
barometer was three-tenths lower at Cincinnati and four-tenths
lower at Louisville than it was at Cleveland, with this high ba-
rometric gradient, the winds were much accelerated in passing
over Cleveland toward the southwest, and it may be that upper
currents were compelled to descend and mingle with them.
The oxygen found was 0*20960, a fall of 0*00008.

On March 20th, there was an area of low pressure just east
of Lake Michigan. The deficiency of oxygen is not explained
by the weather map. The same is also true of the 29th and
30th. .

As far as I can see, it is impossible to discern any connection
between the deficiencies of oxygen observed, and the direction
of the wind at the time of taking the sample.

My own judgment, from the comparison detailed, is, that the
theory that deficiencies in the amount of oxygen in the atmos-
phere are caused by the descent of air from an elevation fairly
well agrees with the facts.

On Jolly's Hypothesis as to the Cause of the Variations^ etc. 429

Art. LV. — On Jolly's Hypothesis as to the Cause of the Variations
in the Proportion if Oxygen in the Atmosphere ; by Edward
W. Morley, M.D., Ph.D., Hurlbut Professor of Chemis-
try in Western Eeserve College.

Jolly has suggested a certain hypothesis as to the cause of
those variations in the ratio of oxygen to nitrogen which are
from time to time observed in the atmosphere of a given place.
He supposes that the volumes of air which exhibit the defi-
ciency of oxygen are brought by currents from the tropical
regions, that the deficiency of oxjgen was caused in those
regions, that it was caused by the consumption of oxygen in
the oxidation of organic matter, and that at some places within
the tropics this consumption is therefore considerably greater
than the liberation of oxygen in the processes of vegetation.

I have proposed a second hypothesis. I suppose that the
volumes of air deficient in oxygen are brought by currents
from an elevation above the surface of the earth, that the de-
ficiency of oxygen was caused while these volumes were at
this elevation, and that it was caused by that assumed physical
action according to which, in a high vertical column of a mix-
ture of two gases, the heavier will tend to become less abund-
ant at the top of the column.

The labor of establishing either hypothesis by experiment
will probably be considerable. I propose to mention some
reasons which seem to indicate that Jolly's hypothesis is the
less probable.

1. There is no direct evidence that the atmosphere near the
equator is poorer in oxygen than the air of higher latitudes.
Numerous analyses agree in this result. Lewy's analyses of
air, collected at Guadeloupe, show that the mean ratio of oxy-
gen to nitrogen there is the same as that at Paris.

2. It is difficult to ascribe to the cause assumed by Jolly a
magnitude sufficient to produce the observed effect.

If a volume of air at latitude fifty degrees is deficient in oxy-
gen by 0*004 or 0*005, the deficiency must have originally been
far greater, if this air has come from the tropics, and has thus
for many hundreds of miles been exposed to admixture with
normal air. We must either, in the first place, believe that at
some parts of the tropical regions there are not very seldom
immense volumes of air, deficient in oxygen to the amount of
0*01 or more ; or, in the second place, we must assert that the
analyses which show deficiencies of oxygen at latitude fifty
degrees amounting to 0*004 or 0*005 are grossly in error, and
that the actual deficiencies are very much less ; or, in the third
place, we must abandon the hypothesis. If the analyses are

430 On Jolly's Hypothesis as to the Cause of the Variations

trustworthy we must abandon the hypothesis, or else attribute
to its supposed cause a magnitude altogether incredible. I will
examine some of the experimental evidence, that the oxygen
in the atmosphere sometimes falls below the mean by as much
as 0*004 or 0005.

I will not cite any analyses made before the year 1841. In
that year Dumas and Boussingault found it necessary to resolve
by experiment the doubt as to whether the true proportion of
oxygen in the air were exactly one-fifth, or were about twenty-
one per cent, or were a variable quantity. If this was the un-
certainty as to the mean of multitudes of analyses, it is obvious
that we can by no means attribute to a single analysis a degree
of precision sufficient to aid in the present inquiry. But in
that year, Dumas and Boussingault used a new method of
analysis, by means of which sufficient accuracy was obtained,
and proposed an elaborate system of analyses on air collected
simultaneously at different places. Lewy went to Copenhagen
to take part in this system, carrying with him apparatus from
the laboratory of Dumas and Boussingault He had the coop-
eration of Oersted, and his results were communicated to the
Academie des Sciences by Dumas and Boussingault. Four of
his results on four samples of air, collected at sea on the voyage
to Copenhagen, showed a proportion of oxygen as low as
0-2045.

Kegnault's results will command entire confidence. A sam-
ple collected in the Bay of Algiers, June 5, 1851, gave 0*2042
and 0*2040 oxygen. A sample collected in the Bay of Bengal,
February 1, 1849, gave 02046 and 0*2045 oxygen.

Jolly has used a new method equally accurate with the com-
mon process, by explosion with hydrogen, and very valuable
as confirming the latter. He measures the tension of a con-
fined volume of air while it is at the freezing-point. He then
absorbs the oxygen from this air by means of a copper spiral
heated by electricity, and again measures the tension at the
freezing-point. The absorption and measurement are repeated
till no more absorption takes place. A sample of air collected
at Munich, June 15, 1877, gave 02053 oxygen, one collected
July 19, gave 0*2056, and one collected November 10, gave
0*2056. Also at six other dates during the same months he
found the amount of oxygen in the air less than 0*207.

A sample taken at this place, September 20, 1878, gave
0 2049 and 0*2049 oxygen. A sample taken February 26,
1879, gave 0*2045. The other analysis of this sample was lost
by the accidental use of hydrogen containing a little air. But
even this analysis, which of course gave the proportion of oxy-
gen too high, gave only 0*2049.

The analyses of Macagno, at Palermo, made by absorbing
oxygen with pyrogallol, I forbear to cite.

in the Proportion of Oxygen in the Atmosphere. 431

It is difficult to resist the conclusion that these analyses show
that sometimes the deficiency of oxygen observed in the atmos
phere at such latitudes as fifty -two, forty-eight, and forty- two
degrees, may amount to 0*004 or 0*005. Then we must either
suppose that not very seldom there might be observed within
the tropics immense volumes of air in which the deficiency
should be several times as great as this, or we must abandon
the hypothesis in question.

If processes of oxidation preponderate over processes of re-
duction within the tropics, there must be a transportation of
organic matter from colder climates toward the equator, there
to be oxidized, but

8. No such amount of transportation as is required by the
hypothesis takes place through the air. For, in the first place,
experiment has repeatedly shown that after a volume of air has
been freed from carbonic acid, there is left in it but a minute
trace of matter capable of undergoing oxidation. Now, if a
given volume of air contained an amount of organic matter
capable, in its oxidation, of absorbing from this volume of air
0*005 of oxygen ;*and if further this organic matter was as rich
in hydrogen as is marsh gas, even then the carbonic acid pro-
duced in some of these experiments would have been ten times
as much as the carbonic acid already existing in the air. And
secondly, if the observed deficiency of oxygen in the atmos-
phere had been produced by the oxidation of organic matter
previously contained in it, the missing oxygen would be re-
placed in part by the carbonic acid produced, which, on the
most favorable assumption, would amount to half the defi-
ciency of oxygen. But experiment has shown that no such
amount of carbonic acid is ever found in air uncontaminated by
local causes, though a very large number of determinations has
been made.

4. The transportation of organic matter required by the
theory does not take place by the waters of the globe. If
Jolly's hypothesis is true a very large part of the organic mat-
ter returned to the air in the form of carbonic acid must be
supposed to be dissolved or suspended in the water which flows
from the land into the sea, to be brought by ocean currents to
the equatorial parts of the ocean, and there to be at last
oxidized.

It may be noticed that this supposition would permit us to
explain the removal of oxygen from the air without the restor-
ation of a corresponding volume of carbonic acid to the same
volume of air, by assuming that the oxidation takes place in
the waters of the ocean while near the equator, but that the
carbonic acid there produced is restored to the air but slowly,
and therefore is not restored to the volume of air which
afforded the oxygen.

432 On Jolly's Hypothesis as to the Cause of the Variations

Now, if this supposed mechanism of oxidation is not consis-
tent with observed facts, the theory that the atmosphere within
the tropics sometimes shows a deficiency of oxygen produced
by the preponderance of processes of oxidation over those of
reduction must be dismissed from consideration. My own
knowledge is far from sufficient to enable me to assert that the
hypothesis is disproved by facts already observed. But I may
mention some of the points in which the theory may be com-
pared with facts capable of easy observation, or perhaps already
observed. Those who are familiar with observations on the
chemistry of sea-water will be able to judge whether the hy-
pothesis is not overthrown by these facts thus compared.

In the first place, if the supposed process of oxidation is the
actual process, it must obviously be about as regular and inva-
riable as the motion of rivers and ocean currents. A vigorous
withdrawal of oxygen from the superincumbent air must then
go on constantly within certain areas of the ocean. Whenever
a volume of air is becalmed over such an area, so that the
cause may operate for some time on the same air, such air
should be highly deficient in oxygen. Now, can we find any
evidence that air over some parts of the tropical oceans is spe-
cially deficient in oxygen whenever the winds are slight? If
the evidence is of the opposite nature, Jolly's hypothesis lacks
confirmation.

Again if the supposed oxidation takes place in the water, a
somewhat rapid transfer of oxygen must go on between the air
and the water. In the regions in question, whenever the sea is
still, then there must be a falling off in the quantity of oxygen
at different depths in the ocean. The contrast in this respect
between equatorial waters and those at forty-five degrees of lat-
itude ought to be capable of observation. A collation of
results already obtained may perhaps afford a decisive test of
the theory.

In the third place, if the supposed oxidation takes place
through the waters of the sea, the retention of the carbonic
acid produced is somewhat protracted. Determinations of car-
bonic acid in the air are very numerous, but no observer has
yet found normal air containing one or two hundredths per
cent of carbonic acid more than the average. Then, even
when air is exposed long enough to oxygen -absorbing water to
lose 0005 of oxygen, it does not gain a noteworthy amount of
carbonic acid. Now if the carbonic acid produced is thus re-
tained, the water of some parts of the equatorial seas must be
very abundant in carbonic acid. There must be a gradual
diminution toward the poles; and further, within all moder-
ate latitudes, there can be no equilibrium between the tension
of carbonic acid in the air and that of carbonic acid in sea-

in the Proportion of Oxygen in the Atmosphere. 433

water. If facts do not agree with these deductions, the suppo-
sition that a large part of the processes of oxidation on the
surface of the globe takes place in sea-water within the tropics
is contrary to the facts.

In the fourth place, it is doubtful whether rivers carry any
such amount of organic matter as is required by the theory.
Determinations of the amount of oxidizable matter contained
in the water of rivers have been chiefly limited to the water
supply of towns. But some observations have been made on
the water of the Nile. Tidy found by the permanganate pro-
cess that 0*23 grain of oxygen was given up to a gallon of the
water of this river. If we take this result to represent the
amount of oxygen absorbed by river water after the water
reaches the tropics, we shall concede much for argument. Such
water could remove 0*001 oxygen from about ten times its own
volume of air. Of course it is difficult to suppose that the
consumption of oxygen can be localized in a small volume of
air. Now, if such waler be diluted with sea-water, and if it
absorbs oxygen from a hundred times its volume of air,
through several degrees of latitude, and if the deficiency of
oxygen to be explained is several times 0*001, it is hard to
believe that the cause is sufficient

5. It is very doubtful whether the whole consumption of
oxygen on the globe would account for the observed deficien-
cies of oxygen, even if we suppose this total consumption for a
certain short period to be taken from one and the same small
volume of air.

Dumas and Boussingault made an approximate estimate of
the amount of oxygen used in a century by all process of oxi-
dation. If we take this estimate we shall find that all the oxy-
gen absorbed from the air in a week, if taken from the same
volume of air covering but half a square degree of the earths
surface, and containing only the lower third part of the atmos-
phere, would produce in this limited volume a deficiency of
oxygen of but one-eighth of one per cent. But we have to
account for deficiencies several times as large, and we cannot
suppose the consumption so limited to a small volume. Then
the theory fails to agree with the facts.

At the foundation of the hypothesis which I have suggested
to account for the observed deficiencies in the oxygen of the
atmosphere, there lies the assumption that in a vertical column
of a mixture of two gases of different densities, there is a ten-
dency to the accumulation of a greater proportion of the
heavier gas toward the bottom, and of a greater proportion of
the lighter toward the top. There has not yet been obtained
■ any direct experimental evidence in favor of this theory of

'' Am. Joub. Sol— Third Series, Vol. XXII, No. 132.— December, 1881.
[ 29

434 W. W. Dodge — Lower Silurian Fossils in Maine.

Dalton. Although the assumption is a simple, and, I think,
certain inference from the known principles of mechanics as
applied to gases, it is desirable that experimental evidence
should be supplied. I have planned two forms of apparatus
and two series of experiments for this purpose ; but the mak-
ing of a more perfect eudiometric apparatus than had heretofore
been used, the carrying on a series of daily analyses in dupli-
cate of samples of air collected at this place, and the providing
for the collection of samples at other parts of the continent,
have used so much of my time and income that so far it has
been impossible to carry out these plans. I hope before long
to supply this deficiency.

Art. LVI. — Lower Silurian Fossils in Northern Maine ;

by W. W. Dodge.

The writer found graptolites in black shale in No. 3 town-
ship, of Range VII, Penobscot county, Maine, in September
last. The fossils are, for the most part, mere bright films
upon the dark rock, and in the small quantity of material
brought away, but one or two individuals are sufficiently dis-
tinct and entire for identification. The fragments are of at
least four varieties ; the Diplograptus type predominates.

The most complete specimen is one of Diplograpius pristisy
but of this the upper end of the axis is broken away. The
cellules are about sixteen to an inch in each rank. Instead of
narrowing gradually from end to end, as the drawings usually
represent, the stipe retains its full width for an inch and a
half and then its edges approach each other rapidly in the next
half inch toward the solid, acicnlar radicle.

A clearly-marked fragment, three-eighths of an inch long, is
of a width only half that of the preceding, the axis is much
more distinct, the cellules, twenty-four to an inch on each
side, although separated from one another nearly to the base
by a rounded interval of about one-third their own width, are
so shaped, with the denticle turned inward, that the appear-
ance of serration in the stipe is subordinate to its linear, par-
allel-edged aspect. The general shape of what is visible is sug-
gestive of Oraptolithus ramosus1 although no bifurcation
appears. Close beside this is a branching fragment upon
which no cellules are discernible, probably its stem.

One or two small, broadly-ovate shapes, perhaps Phyllo-
graptitSj and a few long, slender stems not sufficiently charac-
teristic, or too incomplete, for their relations to be ascertain-
able, conclude the list of forms at present in hand.

The shale in which these remains are embedded is probably

W. W. Dodge — Lower Silurian Fossils in Maine. 435

to be referred to the level of the Utica slate or the Hudson
River formation.

The locality is on the north side of the Wassatiquoik River,
about a mile west of the East Branch of the Penobscot. The
road to Katahdin Lake crosses the southern slope of Wassat-
iquoik Mountain (the eastern and smaller of the two so-called,
the one which stands in Range VII upon the line between
Nos. 3 and 4), while the river of that name runs at its foot.
The shale is at the base of the hill on the eastern side — under
its lee, with reference to glacial erosion.

The occurrence of fossiliferous rocks here is interesting as
helping to correlate the Maine formations with the better un-
derstood Canadian strata, and also as narrowing the circle of
known fossil-bearing beds about the Katahdin granite, whose
position and age may sometime be determined by its relations
to them, when a point of contact is found. Graptolites have
been found in New Brunswick in that great belt of strata
mapped as extending south westward from the Bay of Chaleurs,
witn granite bands on its southeast side.*

The readiest cleavage of the thinly-layered shale which
holds the above described fossils, is at 30° across the plane in
which they lie. There is noticeable uniformity in the position
of the long, slender forms, but the means is not at hand of
determining through how great a thickness of accumulating
strata the parallelism continued. The rock most nearly asso-
ciated with the black shale is a black, or dark-blue, very hard,
thick-bedded slate, of conchoidal fracture, sometimes semi-
translucent in thin flakes. Another rock was too deeply
weathered for examination with such tools as could be impro-
vised. A coarse "greenstone" forms a ledge near by; and the
presence of intrusives doubtless accounts for the condition of
the flinty-looking slates. The only rock noticed in the three
miles to the westward is a dull, greenish, hydrous-looking
eruptive, mostly in boulders. Water-worn pebbles in the
vicinity, apparently of this kind, are streaked with dull red,
and show many cavities.

The nearest observed outcrop to the eastward is of slate with
an easterly dip, on the left bank of the East Branch, near the
water at its summer level, about opposite the mouth of the
Wassatiquoik River. This is a mile and a half north of the
Hunt farm, two miles east of which the road crosses a slate
ledge where the strata dip to the westward. The outcrops of
this slate along the East Branch have been examined by differ-
ent observers, and its strike and dip at many points recorded, f

* J. W. Dawson, Acadian Geology, 1878, supplement to second edition, p. 78.

f C. T. Jackson, Second Annual Report on the Geology of the Public Lands of
Maine and Massachusetts, 1838, pp. 20-24; C. H. Hitchcock, Agric. and Geol.
Maine, 1861, pp. 392. 393.

436 W. W. Dodge — Lower Silurian Fossils in Maine.

One of the most noticeable facts connected with the presence
of this rock between Molunkus and Sherman, along the post-
road from Mattawamkeag to Patten, is the large amount of
clear-white, fine-grained quartz rock scattered by the roadsida
The road from Sherman (No. 3, of Eange V), to the East
Branch at the Hunt farm, gives a good line of section nearly at
a right angle across the line of strike there prevalent, and by
comparison of the dips near the road and elsewhere, it seems to
cross not less than four antiolinals and five synclinals. The
western portion of the road is through woods. There is a
large exposure of nearly vertical beds on the west side of Swift
Brook. Between the brook and Sherman, a distance of five
miles through partially cleared country, the road crosses four
long ridges of high land, whose direction is that of the strike of
the underlying rocks. Upon the hills the strata crop out
occasionally, and in the valleys between flow small streams at
regular intervals of a little over a mile from each other. On
the hill just south of the village of Sherman, and near the line
between Nos. 2 and 3, the slate shows a high dip westward.

Glacial — The parallel courses to which so many of the long,
narrow lakes and large and small streams of the northern part
of Maine conform, appear to indicate the undeviating direction
of primary glacial erosion in that region. The course of trans-
ported bowlders agrees well with this, as in the case of the
limestone in situ in No. 4, E. IX,* observed in scattered bowl-
ders upon the Wassatiquoik and at Whetstone Falls, on the
East Branch, in No. 2, E. Vll.f The uniform shaping of re-
sistant ledges, such as may be seen at Mt. Kineo, and as is
recorded of the slates along Webster Stream and at Grand
Lake,:); indicates in a general way the direction of the force ex-
erted. The glacial striae, as reported, appear to be more than
usually divergent To the two localities of the occurrence of
granite bowlders from an unknown source named by Professor
Hitchcock — north end of Churchill Lake in No. 9 of R. XII,§
and No. 5 of E. VIIIJ — may be added the site of one, high on
the hillside above the East Branch opposite the Wassatiquoik.
The granite pebbles in the bed of the Wassatiquoik at the dam,
four miles above its mouth, may belong to the Katahdin mass,
but the extent of the area occupied by this has not been defi-
nitely determined. The " porphyry " on Soper Brook, T in
No. 8 of E XII, may well be the source of the pebbles of
porphyritic black felsite with quartz grains found at this dam.

* Agric. and Geol. Me., 1862, p. 321. + lb. 1861, p. 393.

1 Thoreau, Maine Woods, pp. 262, 277. § Agric. and Geol. Me., 1861, p. 411.

|[ lb. p. 401. f lb. p. 411.

Cambridge, Mass.

W. J. McGee — Secular Climatal Changes.

437

Art. LVII. — A Contribution to OroWs Theory of Secular Cli-
matal Changes ;* by W. J. McGee, of Farley, Iowa.

Briefly stated, Dr. C roll's theory of secular changes in ter-
restrial climate indicates that during periods of high eccentricity
in the earth's orbit the hemisphere whose winters occur in
aphelion suffers, through the intervention of physical and me-
teorological agencies, a diminution of temperature, while on the
opposite hemisphere the temperature is correspondingly aug-
mented, f It is the object of the present communication to
direct attention to certain meteorological relations tending to
produce such an effect, which appear to have been heretofore
overlooked.

All extensive series of meteorological observations which
have been examined by the writer indicate the existence of a
general law, which may be expressed by the proposition : Any
increase in annual or diurnal thermometrical range is accompanied
by a diminution in mean temperature. Aside from the colloca-
tion of a portion of the results of an elaborate meteorological
survey, for the purpose of establishing an empirical coefficient
indicating the efficiency of the law in absolute measure, no
discussion of this proposition will be here offered.^

The accompanying table I is based upon Charte III of W.
H. Dove's "Verbreitung der Warrne auf der Oberflache der
Erde,"§ and exhibits temperatures along the meridians passing
through the Atlantic Ocean (long. 20° W.) and Central Asia
(long. 120° K).

Table I.
Temperatures at 20° W. and 120° E. of Greenwich.

Long. 20° W.

Long. 120° E.

Latitude.

January.

July.

Range.

January.

July.

Range.

0°

+ 79'2°

+ 77-0°

— 2-2°

+ 77-0°

+ 81-5°

4-5°

70*0

77-0

+ 7-0

60-6

81-5

209

559

68-0

12-1

264

75-4

490

36-0

57-2

21-2

-340

635

97-5

Polar circle

262

45-5

192

40-0

601

100-1

Mean

68-4

733

4-9

534

78*8

25-4

*Read before the Iowa Academy of Sciences, June 25th, 1880, and printed in
brief abstract in the Proceedings, vol. i, pt. 1, p. 24. Read before the Ameri-
can Association for the Advancement of Science at Cincinnati, August 22d, 1881.

fLond., Edinb. and Dublin Phil. Map:., Aug., 1864, Feb., 1867, etc. "Climate
and Time." Edinburgh and New York, 1875.

\ Cf. Proceedings American Association, vol. xxix, Boston Meeting, 1880,
p. 486, etseq. § Berlin, 1852.

W. J. McOee — Secular Climatal Changes.

12'.

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W. J. McOee — Secular Climated Changes. 439

In computing the means the following coefficients were
employed :

Latitude. Coefficient.

0° 1-000

20 -658

40 -357

60 134

Polar circle #074

The mean annual temperatures are 70'8° and 66*1° respectively.
It thus appears that the mean temperature is 4*7° lower and
the thermometrical range 20*5° greater over the land-meridian
than over the water-meridian ; which ratio yields a coefficient
of diminution of 0*23° for each degree of increase in range.
For the present this ratio may be assumed to remain constant.

When the solstices are at right angles to the apsides the
amount of light and heat received from the sun by either
hemisphere during winter or summer is exactly equal to that
received by the opposite hemisphere during its corresponding
seasons. The amount so received may be denominated the
normal accession. When, however, the solstices coincide with
the apsides that hemisphere whose winters occur in aphelion
while its summers occur in perihelion receives a less than nor-
mal amount of light and heat in winter, and a greater than
normal amount in summer, owing to the variation in the earth's
distance from the sun at these seasons. If, then, terrestrial tem-
perature is a function of solar accession, the annual thermome-
trical range on the hemisphere so situated must be greater than
the normal ; while at the same time the thermometrical range
must be diminished on the opposite hemisphere. Manifestly,
too, any increase in the eccentricity of the terrestrial orbit must
intensify this effect, since solar accession varies as the square of
the solar distance.

In table II the solar accession in winter and summer when
the solstices and apsides coincide and the eccentricity of the
terrestrial orbit is as at present (0*0168), is compared with the
normal, values being expressed in degrees Fahrenheit. Table
III exhibits like values for an eccentricity of 0'0747, such as
occurred 850,000 years ago according to Croll's calculation
from LeVerrier's formulae.* Both tables are graphically depicted
in the accompanying diagram.

These tables were computed as follows : — The relative solar

* "Climate and Time," p. 319. Stockwell computes the maximum eccentricity
to be 0*0693888 (" On the Secular Variations of the Elements of the Orbits of the
Eight Principal Planets," Smithsonian Contributions to Knowledge, No. 232 (1872),
p. xi); but his memoir was not accessible when the table was prepared. The
slight diminution in normal accession accompanying increased eccentricity is also
neglected.

440

W. J. McOee — Secular Climatal Changes.

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W. J. McOee — Secular Clhnatal Changes.

441

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442 W. J. McOee — Secular Climated Changes.

intensity at the various terrestrial latitudes has been calculated
by Meech* and expressed in arbitrary units, each representing
■fo of the intensity under the equator at the time of the vernal
equinox. The mean for the whole earth, in the same units, is
66*73. Dove had previously, as a result of an elaborate series
of observations, determined the actual mean temperature of the
earth to be about 58° F. According to Herschers determina-
tion of the temperature of space (which agrees pretty closely
with that of Pouillet), or —239°, this temperature is 297° higher
than that of stellar space. Each of Meech's units is, therefore,
so far as the whole earth is concerned, equal to 4*45° F. This
coefficient has also been assumed to be constant; and the
intensities, both normal and corresponding to the different
degrees of eccentricity, have been reduced to degrees Fahren-
heit by its use. The means were computed by the use of the
following coefficients :

Latitude; Coefficient.

0° 1-000
10 -826

20 -658

30 -500

40 'Sol

50 -234

60 -134

10 -060

80 -015

90 "001

The increase in thermometrical range beyond normal in
tables II and III is 21*0° and 93*7° respectively. Making
use of the coefficient already determined (0'23°), it appears
that these values are equivalent to a diminution in mean tem-
perature over the hemisphere whose winters occur in aphelion of
4*83° and 21*55° respectively, and to a like increase in the tem«
perature of the opposite hemisphere.

It may be added that aside from the specific relations pointed
out, the alternate free summer precipitation and rapid winter
congelation of seasons varying so widely in temperature would
certainly facilitate the formation and conservation of glacier ice.

In the foregoing pages two variable factors have been as-
sumed to be constant. These are the ratios (1) between increase
in thermometrical range and diminution of mean temperature,
and (2) between solar accession and terrestrial temperature.
The first of these ratios appears to augment rapidly with
diminution of temperature, as may be seen from a glance at

*"0n the Relative Intensity of the Sun's Light and Heat," vol. ix of Smith-
sonian Contributions to Knowledge, 1856.

W. LeConte Stevens — The Stereoscope, etc. 448

table I — indeed comparison of a larger number of observations
yielded a larger coefficient Accordingly, since the tempera-
tures dealt with in tables II and III are collectively lower
than those collocated in table I, the use of the coefficient
adopted is probably perfectly safe. With respect to the second
ratio, the lack of correspondence between observed and com-
puted temperatures indicates that results obtained by its use
are excessive. Comparison between observed and computed
temperatures will, however, afford the means of eliminating
errors arising from this cause. Thus, the actual diminution of
terrestrial temperature from equator to pole is about t0° accord-
ing to Dove, while it would be about 212° if proportional to
the solar accession as computed by Meech. Eeducing the
figures 4*83° and 21*55°, derived from tables II and III
respectively, in the ratio of 212 : 80, yields 1*82° and 8'13° as
tolerably trustworthy values for the diminution of mean tem-
perature effected by the operation of the law stated at the
outset

Applying the first of these values to the earth in its present
status, it would appear that the temperature of the southern
hemisphere ought to be about 3*5° lower than that of the
northern. The approximate coincidence between this result
and those derived from observation strengthens the conviction
that the principles detailed in the foregoing pages must be
valid. Applying then the second value to the earth when the
eccentricity is near its superior limit, it appears that the hemis-
pheres should vary in mean temperature by no less than 16° —
that secular summer should prevail in one, while the other was
enshrouded in the snows of its secular winter. The importance
of the agencies described will perhaps be more manifest when
it is borne in mind that during its secular summer more solar
heat and light is received by a hemisphere in winter than in
summer, while on the opposite hemisphere the solar accession
is no less than lf£ times greater in summer than in winter.

Art. LVIII. — The Stereoscope, and Vision by Optic Divergence;

by W. LeConte Stevens.

[Continued from page 362.J

In a previous article* it has been shown that Brewster's
theory of binocular perspective is insufficient to explain vision
through the stereoscope when the visual axes diverge. It takes
account of only one of several elements which combine to de-
termine the judgment of distance, and the significance of this

* This Journal, Nov., 1881.

444 W. LeConte Stevens — The Stereoscope,

should be referred to the sensation of muscular strain rather
than to the intersection of visual lines.

The effect of varying the tension of the rectus muscles of the
eyes in modifying the estimate of relative distance has been ap-
plied in Wheatstone's pseudoscope* and in his reflecting stereo-
scope, though no reference in this connection has been distinctly
made to anything beyond variation of convergence. The fol-
lowing experiment is not difficult. Upon a large sheet of paper
a series of vertical parallel lines are drawn, dO*"11 apart: the
last line of this series forms the first of a second series 60"1-
apart, and in like manner this introduces a third series 70""
apart Gazing at the first series, as if regarding a remote ob-
ject, the paper being lm distant, the images of the lines are
soon combined by diminished convergence. Passing slowly to
the second series, the convergence is still farther diminished,
and it passes into divergence when the third is successfully
combined. The apparent distance of the first series I estimate
at 2m*5, of the second about 3m and of the third about 3m,5.
By intersection of axes, the first should be 6m, the second
infinity, and the third — 6m, my interocular distance being
60mm. The experiment may be varied in many ways ; different
observers form different estimates of distance, but I have found
none who succeeded in attaining divergence thus without ob-
serving an apparent recession of the external image.

To ascertain whether divergence of axes is unconsciously prac-
ticed in the use of the stereoscope, I examined 166 stereographs
taken at random and found the foreground interval to vary be-
tween 60mm and 95mm, the mean being 72mm'9. The average
interocular distance for adults is a little less than 64mm; to
combine without the stereoscope, therefore, divergence is nearly
always necessary. To ascertain the mean deviating power of
the lenticular prisms used in the best instruments, 30 pairs were
obtained through the courtesy of Mr. H. T. Anthony, of New
York. With but slight variation, the focal length was found to
be lS011^. Mounting each pair in succession, parallel rays 64mm
apart were transmitted and received upon a screen l&^'S distant
The mean interval between points of light caught on the screen
was 79,lmm; hence if rays be sent from corresponding stereo-
graph points, separated by a wider interval than this, they will
be not quite parallel after emergence from the prisms, and the
eyes must diverge to receive them ; SO™1111 may be taken as a
limit beyond which most persons will find divergence neces-
sary if binocular combination in the stereoscope is successfully
attained. As this limit is not unfrequently exceeded, axial
divergence, unconsciously attained, is quite common, though

*PhiL Transactions, 1852, parti; or. Phil. Magazine, 1852, pp. 506-523.

and Vision by Optic Divergence. 445

in extent it rarely exceeds 2° or 3°. I have attained 7°,
and Helmholtz * gives 8° as his limit. Several persons of my
own acquaintance have been found able to secure divergence
without the stereoscope, and their estimates of the apparent
distance, size and motion of the external image under various
conditions have not differed much from my own.

In the discussion of normal binocular vision, the expression
" point of sight'1 may be applied theoretically to the intersection
of optic axes. Its apparent position, though not mathematically
determined, may be estimated with more or less error, according
to the skill of the observer. But in discussing the stereoscope
such a definition has to be totally abandoned. The point of
sight then is only the point in space to which the observer
mentally refers the binocular combination of images formed on
corresponding retinal points, where the visual axes, whether
convergent, parallel or divergent, meet the retinas. Its appar-
ent position has to be estimated, not determined by intersec-
tion of lines. In this estimation the relation between the visual
axes is only one of a number of elements that are combined in
the formation of a judgment, whether vision be normal or ab-
normal. Even if stereographs are selected from which phys-
ical perspective is in great measure eliminated, the optic angle
maybe negative; and, when positive, its effect is still antago-
nized by the disturbance of coordination between focal and
axial adjustments, or by the observer's unconscious recognition
of the circumstances under which he has been accustomed to
view an object of the kind represented. A mountain will
never be judged to be so near as a mere diagram, even though
the axial relations be similar in viewing the pictures sepa-
rately. In the stereoscope before me I place a pair of conju-
gate diagrams representing a skeleton cone, alternately approxi-
mating and separating them, in a transverse vertical plane, so
that the optic angle varies between +8° and —3° 45'. The
apparent distance varies between 30cm and 40cm ; if determined
by the optic angle it should vary between +43cm and — 92cm.

The distance of the card remains constant, and tends to keep
the focal adjustment so, while the eyeballs are rotating outward,
tending to produce adaptation of focal adjustment to a greater
distance, the two adjustments being usually consensual. We
are in the habit of associating diminution of convergence with
increase of distance of the object of sight. As long as the eye-
balls continue rotating outward, therefore, the object appears to
recede and to enlarge correspondingly, the recession being
fastest during the change from marked convergence to parallel-
ism. It does not seem possible to express this apparent rate
in mathematical terms.

* Optique Physiologique, p. 616.

446 TP. LeConte Stevens — T7te Stereoscope,

The experiment just described does not imply any unusual
conditions in the stereoscope except that the higher value, 8°,
given to the optic angle is greater than usual. Assuming
72*9,Bm, the mean already found for the stereographic fore-
ground interval, the corresponding angle of convergence after
allowing for deviation of rays is a little less than 2° : the inter-
section of axes is hence still far from the point to which the
focal adjustment is adapted. This fact explains the difficulty
experienced by so many persons in obtaining distinct vision
through the stereoscope, especially those who have passed
beyond middle age and lost in great measure the powerof focal
accommodation.

Most of the stereographs in common use are pictures in
which physical perspective is strong. When these are properly
mounted and viewed in the stereoscope the chief advantage
gained by use of this instrument seems to be that it necessi-
tates variation in the relation between the optic axes, in order
that perfect binocular combination of the different parts of the
superposed retinal images be secured in the subjective Cyclo-
pean,* or combined binocular, eye. If there is perfect super-
position of retinal points on which the foreground of the stereo-
graph is imaged, there is necessarily imperfect superposition of
those on which the background is imaged. If the attention is
then given to the background, slight outward rotation of the
eyeballs is necessitated, and this is habitually associated with
recession of the point of sight. Whether with axial diver-
gence binocular relief is instantly perceptible, as in Dove's
experiments with axial convergence, by illumination of the
stereograph with the electric spark, I am unable yet to say ; I
hope to test this at no distant day. It should be so according
to Professor LeConte's theory of binocular perspective, f

What has been generally given and accepted as the mathe-
matical theory of the stereoscope applies strictly, but only to
the relations involved in taking the photographs with cameras
appropriately placed, so that the axes of the lenses converge
upon some point of the object pictured. When the negatives
are once fixed and proofs from them so mounted that corre-
sponding points from the pair are focalized upon corresponding
retinal points for the observer who binocularly combines them,
with or without the stereoscope, the relation between the dif-
ferent parts of the fields of view combined undergoes no sensi-
ble variation, real or apparent, except between the limits fixed
by difference between the stereographic intervals in the back-
ground and foreground respectively. If the eyes are comfort-
able, after binocular combination is attained, it makes little

* This Journal, III, vol. i, p. 33 et seq.
f This Journal, III, vol. ii, p. 3.

and Vision by Optic Divergence. 447

difference whether, at a given moment, the visual axes are con-
vergent, parallel, or divergent. The combined external image
as a whole is made to appear nearer by convergence and farther
by divergence, but this has no perceptible effect upon the ratio
between the distances of its different parts. Though the dis-
tinctness in separation between foreground and background is
greatly enhanced by the slight variation in axial relations that
is necessitated, the estimation of absolute distance is determined
mainly by physical perspective, and by comparison of the pic-
ture with known realities to which it bears some easily recog-
nizable relation. In the few cases where reversion of perspec-
tive is plainly produced by transposing the pictures composing
the stereograph, it will be found that the difference between
background and foreground intervals is large, and that some of
the elements of physical perspective are relatively weak. I
have examined a number of such transposed stereographs and
found the effect in many cases to be not distinct reversion but
rather confusion. Sometimes in one part of the picture rever-
sion is noticeable, while in the rest there is only decrease in
the apparent distance between background and foreground.
The conflict between physical and physiological perspective
results in a judgment not wholly in obedience to either; gener-
ally the former prevails, but the weakness of the residual effect
is perceived by contrasting it with that obtained by squinting
and thus reversing the sense of the physiological element The
judgment may be regarded as a compromise rather than an
independent selection. In vision by divergence, and in vision
through the stereoscope generally, the binocular relief is largely
due to the variable relation between the optic axes, as different
parts of the stereograph are examined ; while the judgment of
absolute distance is mainly due to physical perspective and com-
parison with remembered realities; it is modified by focal adjust-
ment, and is in practice nearly, but not quite, independent of the
optic angle. This remark would not apply if the optic angle
were very large.

No diagrams can ever represent with perfect accuracy the
apparent positions of objects seen in the stereoscope. If we
neglect such disturbing influences as arise from conflict
between focal and axial adjustments, and from difference
between the optic angle and that between the camera axes
when the pictures were taken, and also disregard the fact that
the surface of the retina is curved while that of a photograph
plate is plane, the following method perhaps will give the best
results.

In fig. 2, let C and C be the centers of two camera lenses
whose principal axes are as usual parallel, and a pair of sec-
ondary axes forming an angle, 0, in a horizontal plane, are di-

448

IV. LeOonte Stevens — The Stereoscope,

rected upon an object, A, in the foreground of a scene. Let
E be the midpoint between C and C ; then EA is a median;
on this prolonged let B be an object in the background. Par-
allel to C C and to the vertical plane of the sensitized plates

behind the lenses, let two planes be passed through A and B
respectively. Let P and Q be any points on these planes, so
related that the straight line Q P passes through E. On the
plates the stereoscopic displacements of the projections of B
from those of A are a b and a' b' ; and it may be easily shown
geometrically that the displacements of those of Q from P are
each equal to a b. This is not shown in the drawing, but a
glance at fig. 5 is sufficient.

Let E be midpoint also between a pair of eyes, R and L, in
front of which the conjugate photographs are placed after be-
ing inverted, and let rays from them be so deviated by semi-
lenses as to make a=9. If the ratio of LR to C'C be known,
the distances EA„ EB„ EP, and EQ, are determined. In
binocular vision the direction of the object seen is always esti-
mated from the position of the combined binocular eye, E, and
is coincident with that of the median between the two visual

and Vision by Optic Divergence. 449

axes, but always somewhere in front* This is universally-
true for normal eves, as may be abundantly learned by experi-
ment, whether the axes be convergent, parallel or divergent,
and whether the median be at right angles or oblique. to the
interocular line, LR In fig. 4,
if E9A, and E,Pa represent these ^ 5" Q

medians, we have both direction 7^ -rf-

and distance determined for these

foreground points. To the right __

eye, B, (fig. 8) appears beyond

and to the right of Kx at an

angular distance determined by

the stereoscopic displacement, axbx;

to the left eye, beyond and to the --\ftrJAr

left at an equal angular distance ;

to the binocular eye, Ea (fig. 4), it is hence homonymously

doubled at b'jbr To secure single vision of it, the optic angle

must be diminished, and through the rectus muscles this at

once suggests to the mind increase of distance, producing at the

same moment heteronymous doubling of the foreground point

Aa, as in fig. 4. Similar remarks apply to Pa and Qa.

If a be less than 0, as is often the case, this fact will cause
the observer to estimate Aa to be more distant than it is repre-
sented in the drawing, but by no means necessarily so distant
as the actual vertex of a. If a be reduced to zero or become
negative the sensation of still further change of muscular ten-
sion makes the apparent position of Aa recede still more, and
also that of Ba in the same proportion ; but in no case is this
determined by intersection of visual axes except when a=0.
No one can have failed to notice the exaggeration of perspec-
tive in some stereoscope pictures, produced by making 0 large
while a is rendered small or negative by mounting the pair too
far apart. This indeed was noticed by Wheatstone,f who
approaches very near to the idea of possible optic divergence
accompanying the perception of binocular relief, when he says,
"but I find that an excellent effect is produced when the axes
are nearly parallel by pictures taken at an inclination of 7° or
8°, and .even a difference of 16° or 17° has no decidedly bad
effect.'' His preconception that optic convergence, even
though slight, is indispensable, prevented his apprehension of
more than part of the truth. He states, as a remarkable pecu-
liarity, that "although the optic axes are parallel, or nearly so,
the image does not appear to be referred to the distance we
should, from this circumstance, suppose it to be, but it is per-
ceived to be much nearer." Such large angles as 17° are sel-

* This Journal III, vol. i, p. 33 et seq.

f Wheatstone, Physiology of Vision, Phil. Mag., 1852, pp. 513-514.

Am. Jour. Sci.— Third Series, Vol. XXII, No. 132.— December, 1881.

450 W. LeConte Stevens — The Stereoscope, etc.

dom resorted to at present. For taking stereographs of statu-
ary, etc., the lenses of the binocular camera are not often more
than SO0111 or IQQ™ apart.

That muscular tension is more important than mere intersec-
tion of axes in affecting the judgment of distance and size
may be shown by aid of Wheatstone's reflecting stereoscope.
Having placed the two outline drawings, each 20cm from its
mirror so that a distinct combination is attained by axial
parallelism, the judgment of distance is as definite as could be
desired. Upon converging the axes strongly and giving atten-
tion successively to the two monocular images thus obtained,
each appears greatly diminished in comparison with the binoc-
ular image just seen. Moreover, at the moment one of them
is made an object of special attention, the other grows slightly
larger. We have thus images of three apparent sizes, accord-
ing to the degree of muscular tension with which they are
separately regarded, while the visual angle remains constant
The visual axes are converged until their intersection is not
more than ocm or 6cm off, and the illusive impression is that each
image is in the direction of its own axis much beyond the inter-
section. But in fact, being monocular images, the direction of
the center of each is that of a secondary axis, the right eye
perceiving that on the right, instead of the left. Since the optic
center and center of rotation are about 6*6mm apart, the former
being displaced toward the nasal side during the experiment,
the two secondary axes meet at a very distant point in the rear.
While the distance of the monocular image is indeterminate,
it is judged easily enough to be not at the vertex of either the
apparent or real angle determined by the meeting of axes.
The experiment is very striking and is not difficult. We have
a binocular image, of little more than natural size, with clear
judgment of distance, as the result of axial parallelism ; two
monocular images, of diminished and separately variable size,
with very uncertain judgment of distance, as the result of
axial convergence, the principal and secondary axes being sub-
jectively interchanged. The apparent diminution in size of the
monocular images may be easily observed by crossing the eyes,
while holding in front a card on which a sharply defined outline
is drawn. I may discuss this still further in a future paper.

No theory of the stereoscope that includes axial divergence
is possible, unless we recognize the subjective combination of
the two eyes into a single central binocular eye as the point of
origin in all perceptions of direction, distance and form. What
is essential for binocular vision is not any particular relation
between visual axes but rather superposition of retinal images
in the binocular eye. What seemed uppermost in the minds of
Wheatstone and Brewster * was superposition of external vir-

* Wheatstone, Physiology of Vision, Phil. Mag., 1852, pp. 243 and 246.
Brewster, on New Stereoscopes, P\iV\. lfog., \852, pp. 17-26.

J. D. Dana — "Karnes" of the Connecticut River Valley. 451

tual images by causing rays from two pictures to deviate and
appear to come from one central combined external picture.
This would exclude the possibility of optic divergence, but seems
to be still the most generally accepted theory of the stereoscope.
In securing dissimilar pictures of the same object by con-
vergence of camera axes we secure the conditions for the per-
ception of binocular relief by divergence of visual axes.

In the diagram attention is called to the identity in position
between the optic center of the binocular eye and the only
point through which lines can be drawn in such a way as to
cause the stereoscopic displacement to be constant for projec-
tions of the points where these lines cut the foreground and
background planes. This fact alone is enough to suggest that
in vision through the stereoscope the midpoint between the
eyes must be the point of origin from which distance and direc-
tion are to be perceived. A truth that was first recognized as
a physiological necessity is thus confirmed by purely mathe-
matical considerations.

The dissociation between focal and axial adjustments in
^ forced convergence or divergence is at first troublesome and
productive of indistinct vision, but this vanishes in great
measure after a little practice in ocular # gymnastics. If the
eyes are comfortable we are apt to forget that the vision is
abnormal, and to assume that conditions exist which belong
only to normal vision. To ascertain what modifications are
imposed by physiological conditions upon the generally ac-
cepted mathematical theory of the stereoscope has been the
' chief object of the present investigation.

New York, Sept. 16, 1881.

Art. LIX. — On the relation of the so-called " Karnes" of the
Connecticut River Valley to the Terrace formation ; by James
D. Dana.

Since the publication of my papers of 1875 and 1876 on
the stratified drift of Southern New England treating espe-

-f cially of the character and effects of the flood closing the era
of ice, large additions have been made to our knowledge of the
terraces of the Connecticut Valley, and of some other parts of

i Northern New England, through the New Hampshire Report
of Mr. Warren Upham, published in 1878.* In his Report,
Mr. Upham describes in detail the stratified drift or terrace-

* Geology of New Hampshire, Part III, Chapter i, Modified Drift in New
Hampshire, by "Warren Upham, pp. 3-177. 1878. A synopsis of Mr. Upham's
Report, by its author, was published in this Journal, vol. xiv, p. 459, 1877.

452 J. D. Dana — "Karnes" of the Connecticut River Valley.

formation of the valley ; . gives the heights of the terraces
above the river (and above mean tide) from careful level ings
along its course, commencing near the source of the river in
Connecticut Lake, 1618 feet above the sea ; discusses the
origin of the deposits and of their various features ; and pre-
sents his very valuable topographical details on a map of the
valley occupying a series of plates. Besides the ordinary
stratified drift, Mr. Upham finds gravel ridges or deposits to
which he applies the name " Karnes." According to his obser-
vations, the " kames" were formed before the deposition of the
beds of the terrace- formation and after that of the till or un-
stratified drift, so that they represent an intermediate stage in
the progress of the era and call for special explanations.

The facts from the Merrimac Valley also are presented in a
similar way, and with like deductions.

In the study which I had made of the Quaternary of South-
ern New England, and less perfectly of drift-phenomena else-
where, I had been led to refer all the stratified drift above
the till to the terrace-formation ; and no later observa-
tions in river valleys had resulted in the discovery of any
thing answering to Mr. Upham's u kames." During the past
summer, I have been over the region of the Connecticut val-
ley described by Mr. Upham, in order to obtain a full under-
standing of his facts, so as to be able to incorporate them with
the knowledge I had previously acquired, and I here give an
account of what I observed, with my conclusions.

That the subject may be rightly apprehended, I preface my
statement with a brief mention, first, of some of the general
facts respecting the stratified drift-deposits which I had gath-
ered from personal study, and, next, of the facts and deduc-
tions which are brought out by Mr. Upham with relation to
the "kames."

I. — (1.) Scratched bowlders and till are almost uniformly
absent from the valley terraces of New England and from the
stratified beds that make the terrace-deposits. Exceptions
occur where the underlying rocks having till over them come
so nearly to the surface of any terrace that the till outcrops*

(2.) The layer of till of the hill-slopes is continued beneath
the terrace deposits; showing that along the valleys the till with
the bowlders was generally deposited first.*

* In the street adjoining my own house, in New Haven, a trench, excavated for
a sewer, passed through ten feet of stratified drift, or of the terrace formation,
and then opened into a deposit of gravel and scratched stones (including some
bowlders of eight to ten cubic feet) ; and, below two or three feet of this kind
of material, entered the Mesozoic sandstone of the region. This sandstone rises
in a ridge, above the level of the terrace, 400 yards to the north of the excava-
tion, and must have constituted both the shore and bottom of the valley- waters at
the time of the deposition.

J. D. Dana — "Kames" of the Connecticut River Valley. 458

(3.) The stratified drift of the valley consists ordinarily of
fine material below, and coarser toward or at the top ; the bot-
tom portion being commonly of clay or loam, or fine sand
with frequently more or less clay ; then, following this, layers
of sand often fine, but often with more or less gravel; then
above, toward the top in the upper fifteen or twenty feet,
coarser gravel, and in some regions cobble-stone beds; an
order of arrangement, which indicates — in accordance with
ordinary hydraulic principles — that the flow of the depositing
waters was, as a general thing, less rapid at the time of the
early depositions, and most so during the later or that of maxi-
mum flood. Exceptions exist along those streams that were
torrents, and sometimes at the mouths of tributaries to large
streams.

An uppermost sandy layer, of two or three feet thickness,
frequently exists, indicating that the ebb commenced in a les-
sened rate of flow.

(4.) The portion of the terrace formation in a river valley
that is nearest to the river or adjoins the channel-way, may,
and often does, consist largely of beds of coarse gravel or cob-
ble-stones, while one or two hundred yards away from the
river it is composed chiefly or wholly of beds of sand ; the
river-border deposits being thus coarse because of the sifting
or assorting action of the stream in violent flow along its
channel or against one or the other side of it. And the
coarseness may diminish down stream, because of greater
remoteness from the source of coarse material, and also because
of a change in the rate of flow, producing less power of trans-
portation and so allowing of a deposition of the sands drifted
out above.

(5.) Terraces of different degrees of coarseness and of dif-
ferent heights were sometimes simultaneously made on oppo-
site sides of a stream, owing to the different rates of flow in the
waters along the two sides.*

* Along the middle one of three streams entering the New Haven Bay, called
Mill River, coarse gravel and cobble-stone deposits characterize the New Haven
terrace-formation all the way to the harbor ; they are vastly coarser on the west
side of the stream than on the eastern, and in the southern part of its course are
most so along a more western line away from the present stream. Moreover, the
deposits make a terrace on the west side of the stream of only twenty-five feetabove
mean-tide level, while on the east side, where the material is so much less coarse,
they rise to a height of forty-three to forty-five feet, or the ordinary level for the
Hew Haven plain at that distance from the Sound. Those coarsest beds were
made under the sifting action of the violently flowing waters (the pitch of the
stream for some miles back being eight to ten feet a mile), and hence, that is, be-
cause of the loss of the finer material in this way, the height attained on the
tide of most rapid flow was twenty feet below the normal height. Moreover, the
violent waters were probably those of the nearing maximum stage of the flood;
for the coarse gravel deposits (as various sections show) extend down but fifteen
feet from the surface, and rest on beds of sand and fine gravel.

454 J. D. Dana — " Karnes ' of the Connecticut River Valley.

(6.) The terrace-formation of a large and broad valley was
made mainly, not from what its river transported, but from the
contributions of tributaries. Consequently, (a) the height of
the maximum flood is best registered in terraces at the mouths
of tributaries, and (b) where tributaries fail for long distances,
there may be only low terraces ; further, (c) the coarsest gravel
beds should exist in the deposits about the mouths of tribu-
taries, and especially in those made along the banks of the
main river near these mouths, where the contributions were
subjected to the sifting action of the swiftly flowing river.

(7.) The extent and height of the terraces made along any
part of a valley depended not merely on the amount of con-
tributed material, but also largely on the size and form of the
valley. Where very wide and deep, like many lake basins, the
deposits were generally sufficient to make only low or narrow
terraces ; where narrow, the flow of waters was sometimes, be-
cause of the diminished width, too rapid for any depositions;
but where the valley, though narrow along the main channel had
a broad region of ledges on either side that became overflowed
when the waters were nearing their maximum depth, a high
terrace might then have become of great width ; for the shal-
low region favored deposition by offering resistance to the flow,
and however wide needed little material to cover it Just as
this condition favored the making of a broad upper terrace, so
it favored the making of a wide terrace at lower levels, espe-
cially if the flow of water continued long at those levels.

(8.) Ice floes, bearing sand, gravel and bowlders, added to
the transported material for the terrace-formation ; and they
should have been abundant during the breaking up, at the
time of maximum flood. Being carried by the waters, their
distribution of material would have taken place for the most
part in accordance with the principles above explained.

II. Mr. Upham adopts in his New Hampshire Report, the
view that the valley formations are deposits made by the flood
from the melting glacier, and it appears from his explanations
that he would accept without objection several of the above
explanations. The points of discrepancy, however, are many
and important. I cite here only those relating to the "kames"
and mostly in the author's words. The term modified drift is
used by him for stratified drift.*

Page 12. "The oldest of the deposits of modified drift are
long ridges, or intermixed short ridges and mounds, composed
of very coarse water- worn gravel or of alternate layers of gravel
and sand irregularly bedded." " Their position is generally
along the middle or lowest parts of the valleys." Wherever the

* I have avoided the terra modified, because it is not known to express in all
cases the truth, preferring the non-committal term stratified.

e/. D. Dana — "Karnes" of the Connecticut River Valley. 455

ordinary fine alluvium of any terrace occurs adjoining a kame,
" it overlies or in part covers the kame deposits," the ordinary
terraces being of later formation than the kames.

Page 43. Along the Connecticut, between Vermont and New
Hampshire "from Lyme to Windsor, a continuous gravel ridge
or kame extends 24 miles, along the middle and lowest portion
of this valley, with its top 100 to 250 feet above the river."
" Its material is gravel and sand in irregular obliquely-bedded
layers, always showing an inclined, and in most cases a distinctly
anticlinal or arched stratification. The gravel, which always
forms the principal part of the ridge, varies in coarseness from
layers with pebbles only 1 or 2 inches in diameter to portions
where the largest measure 1£ or 2 feet. The fine kinds prevail."
"The sand is usually coarse and sharp, well suited for ma-
sons' use ; it occurs in layers of varying thickness up to one or
two feet, but sometimes it is wholly wanting." "All the mate-
rials of this kame, and of its remnants along this valley, are
plainly water-worn and stratified."

Page 44. "The most important feature of this kame, if we
compare it with others in New Hampshire, is that along its en-
tire extent it constitutes a single continuous ridge which runs
by a very direct course nearly in the middle of the valley, hav-
ing no outlying spurs, branches, parallel ridges, or scattered
hillocks of the same material associated with it."

HARTLAND. Plalnfield. Cornish. WINDSOR.

Conn.R. * * 5 ft Conn.R. Conn.R. £ J

Southern part of the " Kame,'1 in Hartland and Windsor. l, :;

Page 45. "In calling this kame continuous from Lyme to
Windsor, it is not meant to imply that it- is now entire, since
it has been frequently cut through and considerable portions
swept away by the main river and its tributary streams;
but that so much of it remains as to make it certain that it
originally formed an unbroken ridge." The former southward
continuation of the kame below Windsor is stated to be
"probable though now shown by only a few fragments." Mr.
Upham then mentions, on p. 47, facts from the vicinity of
Windsor, -showing at one place in the valley " gravel which is '
unmistakably that of a kame" ; just south, what "seems to be
a kame deposit;" and \\ miles south, "distinct remainsW the
kame," forming the east border of the terrace, both kame and
terrace being 150 to 170 feet above the river. For the next 11
miles no indication of the kame are seen ; and beyond are only
remains at long intervals more or less distinct.

456 Jl D. Dana — il Karnes1* of the Connecticut River Valley.

The preceding figure is part of a section, given on p. 45 of
the Report, intended to show the general features of the south-
ern part of this kame ridge (exaggerated relatively in height)
in Hartland and Windsor : and the following (from p. 40) is a
transverse section of the Connecticut valley through the Hart-

^Ddtt- i™*.

Section of the Hanover Kame. fr, on tbe
east side of the Connecticut River, r: mm,
the tfll-eoTered underlying rocks: a. ter-
race in Norwich 505 feet Men above mean

Transverse Section in Hartland and Plainfield.

land deposits, exhibiting the position of the kame just west of

the river channel, and its relation to the terrace-formation and

the several terraces of the valley.

The adjoining figure, from page 37 of Upham s Report, will
0 help further to explain the au-

thor's views. It represents the
Hanover "kame," with the out-
line of the terrace-plains on the
opposite sides of the Connecticut
The kame, &, is represented as
constituting a ridge, coarsely

^ . i ^ ,~ * * k i ♦ stratified, buried beneath the ter-

tide level and 132 feet above low water in e

the river; b, terrace in Hanover 515 to 545 race formation. Up tO ltS VerV top,

on the landward side, but uncov-
ered on the side toward the river. A section taken a little
farther north would have exhibited the akame" projecting
above the terrace- plain.

a Karnes" are also described as occurring in the valley to the
north, bat at long intervals.

As to origin :

P. 176. The kames " were deposited, as explained on pages
13 and 14, by glacial rivers, at the final melting of the ice sheet,
in channels formed upon tfie surface of the ice. When the border-
ing ice- walls and its separating ridges and masses disappeared,
the gravel and sand remained in long steep ridges, or in irreg-
ular short ridges and mounds."

P. 4rL The infrequency of angular fragments and bowlders
shows '• that the kame of the valley was formed in an open ice-
channel'' P. 14 On the ice in these "channels were deposited
materials gathered by the streams from the melting glacier.
By the low water of winter, layers of sand would be formed,
and by the strong currents of summer, layers of gravel, often

J. D. Dana — "Karnes" of the Connecticut River Valley. 457

very coarse, which would be very irregularly bedded." "The
glacial rivers which we have described appear to have flowed
in channels upon the surface of the ice, and the formation of
the kames took place at or near their mouths, extending along
the valley as fast as the ice-front retreated." P. 44. " When the
river entered upon the work of excavating itsjjpresent channel
in the alluvium, the kame was a barrier which confined erosion
to the area on one of its sides and protected its opposite side ;
so that this ridge of gravel often forms the escarpment of a
high plain with the river flowing at its base."

The chief points urged by Mr. Upham with regard to the so-
called " kames," exclusive of those pertaining to mode of
origin, are: — origination : after the till and before the stratified
drift of the terraces ; material : chiefly beds of gravel ; structure :
usually arched or 'anticlinal; situation: generally between the
river and the upper terrace, and often making the riverward
limit of the latter, also, in many cases, partially isolated and
ridge-like, owing to a depression between it and the terrace,
and sometimes a large depression ; height: frequently the same
with that of the upper terrace or a little above it. Further,
his descriptions show that he refers coarse cobble-stone deposits
in the riverward part of the terraces always to "kames."

In my study of the facts relating to the Connecticut Valley
"kames," I commenced at Windsor, the southern limit of the
great line of "kames," and examined the valley formations at
various places from that place to Lyme, and thence northward
to Barnet and Lancaster : and the report I have to make is un-
favorable to the "kames." I made levelings at various places
in order more surely to identify the terraces mapped by Mr.
Upham, and to apprehend their true relation to the Connecticut
Valley, and also, to add, if possible to the facts. My trials
soon satisfied me as to the essential correctness of his measure-
ments.

Windsor. — At Windsor (on the west side of the Connecticut)
the upper terrace of the village rises to a height of about 216
feet above the river or 520 feet above the sea-level. I saw no
good opportunity for a satisfactory examination of the material
of its lower part beneath the village; but in the upper part
found it to be fine sand and loam, though somewhat pebbly
through the upper 25 feet.

South of the village lies Ascutney Pond, a north and south
body of water made by damming the waters of Ascutney brook ;
on the east, the pond is separated from the Connecticut River
by a ridge of stratified material, nearly flat-topped, having
about the same height as the upper terrace. Mr. Upham says,
somewhat doubtingly, that this ridge "seems to be a kame de-

458 J. D. Dana — " Karnes1* of the Connecticut River Valley.

posit" It ends southward in rocky ledges. A mile and a half
farther south, the high river terrace consists along its eastern
margin of very coarse gravel, and is pronounced therefore to
be in this part the " remains of the kame/'

I found this ridge east of Ascutnev Pond to consist mainly
of loamy material, or sandy loam, like the terrace west of
Windsor, with little gravel and that chiefly over its upper sur-
face or in an upper layer. But directly west of the Pond there
is a terrace (not referred to particularly by Mr. Upham) whose
material is made up largely of coarse gravel, in part cobble
stones, and coarsest in its upper layers, which in this portion is
as much entitled to be called •* kame ** as that " a mile and a
half farther south." This terrace rises westward to a level plain
at 448 feet above the sea-level, and then another at 480, and this
last rises to 525 feet, which is the height given by Upham for
the possible 44 kame " east of the poni Its gravelly character
continues, but diminishes northward.

I found no evidence whatever that the eastern portion of the
terrace was a "kanae,"' that is, a part separate in time of
origin from the rest : the evidence was all against such a con-
clusion. Moreover there was an abundant source at hand for
the amount of coarse gravel and cobble stones ; for Ascutney
or Mill Brook, rising in northwest Reading, flows with rapid
descent by the north side of the loftv Ascutnev Mountain

mi ml ml

(3320 feet), and would have been a great transporter from the
drift-covered country it drained. The position of the stream,
and its relation to the southward-flowing Connecticut, account
for the distribution of the " kame " material or coarse gravel
of the Windsor region, including that of Windsor village, men-
tioned by Mr. Upham, and also for the isolation of the ridge on
the east side of the pond.

Txco miles north or Windsor a kame is entered on Mr. Upham's
map. Much coarse gravel here makes the outer or westward
portion of the upper terrace, which is by the map 500 feet
above the sea- level. Besides coarseness of gravel. I saw no
evidence of a kame, that is of any deposits that were distinct
from the terrace in original deposition. A brook comes from
the west just north of the %* kame."

Uartland station . 4i??i. north of Windsor. — At this place stands
the *% kame " ridge represented in Upham's section reproduced,
on page 456. of which he says : '• At one place, east of Hartland
depot, this plain (that of the upper terrace) has been swept
awav from both sides, and the kame forms a conspicuous steep
ridge 125 feet in height [above the depot plain, 240 feet above
theriver]. Wherever it is exposed, it is readily recognized by
the pebbles which strew its surface, and which are very rarely
found in the ordinarv moditied drift of the vallev.r

J. D. Dana — "Kames" of the Connecticut River Valley. 459

I ascended this prominent " kame " with my interest greatly
augmented by the description in the Eeport. The narrow plain
between it and the station (see the section) was covered with
pebbles from an underlying gravelly layer. The same gravelly
layer made apparently the base of the " kame," for some loose
cobble-stones were found at the base of the slopes and for 10 to
15 feet above. But on ascending the ridge, no gravel was any-
where observed at a higher level ; on the contrary, all was fine
loam or fine sandy loam to the very top. And on descending,
the same proved to be true ; the only gravel was at its base, 50
feet above the river and nearly 200 feet from the top, according
to my leveling. There were no good sections, but if made of
gravelly layers, loose stones or pebbles would have worked out
to the surface and shown themselves somewhere over the earthy
sides.

A few rods west and northwest of the Hartland depot there
was gravel in the terrace, and much of it; and according to the
description of " kames," there was, as far as material goes, a
" kame." On the first terrace-plain, about 65 feet (by my level-
ing) above the railroad track (or 486 to 490 above the sea level)
large stones (1 to 10 inches across) lay over the surface, and
very many in the sloping section of it facing the railroad track.
From this terrace-plain, some rods to the west, there is an
abrupt rise to the next higher terrace, and here the material is
fine sandy loam with no pebbles. The natural conclusion is
that the gravelly stratum is a lower part and the sandy loam an
upper part of the same terrace formation, precisely as in the so-
called " kame ;" and, secondly and accordingly, that the " kame"
is nothing but a piece of the terrace-formation. Lull's Brook
here comes in from the west and is no doubt accountable for
the coarse gravel.

North Hartland, nearly 4 miles north of Hartland. — At North
Hartland station, there commences, according to Upham's map,
another " kame " a mile long ; it is near the river, close by the
west side of the railroad. Its height by the map is that of the
upper terrace-plain, or 550 to 560 feet above mean-tide level.
Very coarse gravel shows itself in an oblique section of the ter-
race formation or " kame " facing the railroad, becoming cobble-
stone layers 70 to 80 feet above the track. The coarseness
diminishes to the northward. The large torrential stream,
Quechee river, rising in the Green Mountains, enters the Con-
necticut here, and seemed to be a sufficient source for all the
depositions; while the fact that the contributions were contri-
butions to the Connecticut, which was in rapid flow off its
mouth, accounted for the distribution of the especially coarse
accumulations along the riverward border of the terrace.

460 J. D. Dana — "Kames" of the Connecticut River Valley.

In Hartford, Vt., at White River Junction, 4£ miles north of
Nortfi Hartland. — On the west border of the Connecticut about
White Eiver junction, or at the mouth of White Eiver, there
is a short "kame" according to UphanVs map south of this
river, and one, a mile and a half long, north of it The White
Eiver valley is here very broad, like a piece of the Connecticut,
and as it rises westward but slowly, it opens to view a portion of
the Green Mountain range, which is the chief source of its waters.
The Connecticut valley terraces of the region are high — not far
from 180 to 235 feet above the river, or 510 to 570 above mean
tide level ; but that to the north, owing to the retreat in the
hills is much the most extensive, and hence the greater length
of the northern of the two. "karnes."

The southern " kame" commences within a few yards of the
railroad station and hotel, where an excellent section of it is
exposed to view. The pitch of the slope toward the Connect-
icut is about 40°. The structure is well-bedded throughout
The layers consist of cobble-stones, finer gravel and coarse
sand. The coarsest cobble-stone layers are below, and some of
the rounded stones from them are one to over one and a half
feet in diameter. Other cobble-stone layers, less coarse, occur at
different levels above, alternating with an increasing thickness
of gravel ; and toward the top, which is near the top of a ter-

40?'

Upper part of the section of the " kame."

race-plain, the material is finer gravel and sand. Fig. 4 shows
the position of the cobble-stone beds in the upper half of the
section. The beds are not continued through the figure because
in the western portion of the section the layers were mostly con-
cealed by slides ; but it was manifest from the few and smaller
stones on the surface that there was a marked diminution in
coarseness to the westward even in the first 100 yards.

The cobble-stone beds exposed to view in the section stop
short off below at a level about 20 feet above the level of the
railroad track, or 56 feet above the river (low water), and un-
derneath occurs a bed of coarse sand, having the flow-and-
plunge structure well marked. A section of the same sand-bed
was observed 70 yards to the south, evincing that it is not a
local deposit. But the depth to which it was exposed was
hardly 8 feet ; and it may be that there are other stony layers

J. D. Dana — "Karnes" of the Connecticut River Valley. 461

underneath. Above the top of this section there is a nearly
even terrace-plain, 160-170 feet above the river, or 493 to 503
above mean-tide level. This plain rises to the southwest to a
maximum height (not observed by Upham) of 570 feet. The
material is fine sand and sandy loam. But along the river-
ward border of this terrace plain, where it is lowest|(493ffeet),
stands a steep narrow ridge, 50 to 65 feet high, which, judging
from the stones of its surface, is made chiefly of beds of cob-
ble-stone gravel. The top is 546 feet (Upham),f,[above] the
sea.

The cobble-stone character of this ridge and its position
make it eminently " kame"-like. But the evidence from the
section described, as well as from the plain around, is directly
opposed to the idea that it is the top of a buried gravel ridge,
existing there before the terrace material was deposited.

In the section, the obvious facts are : that these upper cobble-
stone beds — those of the top ridge — are underlaid, first by layers
of sand and fine gravel, and then below by alternations of coarser
beds ; that all the beds are horizontal instead of arched ; that they
diminish rapidly in coarseness westward, or up White Biver,
showing this even in the first 100 yards, and less rapidly south-
ward or down the Connecticut, the coarsest deposits being at
the angle in the terrace formation between the two streams.
All the beds are evidently those of the terrace-formation, and
the cobble-stone ridge at top is the youngest instead of the
oldest

The northern u kame" or that north of White Biver, com-
mences about half a mile from the railroad station. A sec-
tion is exposed to view at its southwest angle, facing White
Biver, exhibiting very similar features to those presented by
the northern kame near the railroad. It is horizontally bedded
throughout, and the coarsest beds are below : and some of the
rounded stones from the beds are two feet in diameter.

But the cobble-stone beds are of less extent, for they reach
only to a height of 45 feet above the railroad track, or 81 above
the river, and are coarsest at 16 to 26 feet. Above the 45 feet
the beds are of coarse and fine gravel, and increasingly finer to
the top of the terrace, 510 feet (Upham) above mean tide.
Below 15 feet above the railroad the beds are concealed.

On the top of the high terrace, along its riverward border,
some spots of cobble-stone gravel occur, but no distinct gravel
ridge like that of the southern kame.

The interior of this "kame" is fortunately more or less per-
fectly exposed to view in both longitudinal and transverse sec-
tions; and it is remarkable that these sections have nothing
"kame "-like in them.

The longitudinal or north and south section extends along a

462 J. D. Dana— •" Karnes11 of the Connecticut River Valley.

cut or gorge commencing close by the west side of the cobble-
stone exposure just described. The gorge (with its carriage
road at bottom), seemingly divides off a veritable " kame " from
the terrace west of it ; but the beds on the opposite sides of this
cut so correspond, that there can be no doubt of stratigraphic
unity.

The section of the " kame " along this gorge is more or less
obscured by slides, but not in all parts. It shows, first, that
the stony beds diminish rapidly in coarseness away from White
river or to the north. One hundred feet up the gorge, the
cobble-stones are half smaller and extend up to a height of only
30 feet above the level of the railroad, or 66 feet above the
river, and bevond this thev continue to diminish. At 400 feet
up the gorge, the ascending road along its bottom reaches a
height of 28 feet above the railroad level, and here, in the ex-
posed section on the east side, there is a bottom layer of sand
and above the sand 30 feet in thickness of clay ; and this clay
outcrops on the west side of the gorge as well as the " kame "-
side, proving that the deposits of the supposed " kame " are one
in bedding and material with those of the terrace formation,
just as the high terrace plain above the whole (510-520 feet) is
one from the Connecticut westward.

To the eastward of this section, toward the railroad, the de-
posits diminish in coarseness : and the same change continues
northward along the railroad, where the surface material of the
lower part of the terrace-slope shows stones only to a height of
20 or 30 feet, or less, above the track.

One of the east-and-west sections of the " kame" exists about
half a mile north of the south end. A gorge intersects the
deposit which is cut down to the level of the railroad
track and extends inward (westward) to the center of the
" kame" line. But there is nothing kamelike within it, and
least of all at its inner extremity. On its north side, it has no
cobble-stone beds, not even gravel beds ; the material is fine
sand delicately straticulate. On its south side, in the part
nearest to the river, there occurs, in a large mass that has slip-
ped down from above, a thin bed of small stones (three inches
in diameter) with some gravelly and sandy layers below ; else-
where the material is sand. In the inner part of the cut, be-
sides the fine sand, there is a bed of light-colored clay and
sandy clay between 60 and 90 feet above the railroad, and
above this within a few feet of the top, sand and fine graveL

There is however one " kame'Mike feature. Upon the top
of the terrace (here about 510 feet above mean tide), near the
inner end of the gorge there is an isolated knoll about 30 feet
high, and of rounded form, which has many cobble stones over
its surface, some of them 10 inches in diameter — indicative of

e/. D. Dana — "Karnes" of the Connecticut River Valley. 463

cobble-stone beds within. It has no continuation north or
south. The material of the plain around is sand or fine gravel,
like that of the upper part of the section. The following figure
shows the position of the gravel-made knoll, the form of the

■VJ

surface north and south, and a section of the beds which accor-
ding to the facts in the gorge, underlie it. The material of the
knoll at top is manifestly the latest of the terrace-deposits.

The beds below the level of the railroad were not exposed
to view at this place.

The second east-andwest section occurs about a fourth of a
mile farther north. A long and deep gorge here cuts through
the deposits of the 520-foot terrace, nearly to the level of the
river, intersecting the "kame" line and extending nearly half
a mile to the westward. There is less of kame-like features
here than in the preceding gorge. Along the bottom of the
deep cut, where a stream flows in some seasons, lay pebbles
and some cobble-stones, derived from layers below the level of
the railroad track, and these continued for about 300 yards
west of the railroad. At a higher level the material is sand or
very fine gravel, and the latter in some parts at the top. The
sides of the cut were mostly covered by the fallen sands, so
that the existence or absence of beds of clay could not be ascer-
tained. A unity of structure from east to west was manifest.
Nothing answered to the description of a kame ; all was appar-
ently of the terrace formation.

Hanover j New Hampshire, four miles north of White River
Junction. — In the town of Hanover, a "kame," according to
Upham's map, borders the Connecticut for three miles, to a
point north where the river makes an abrupt bend, and thence
it follows in the same direct line, the western or Vermont side
of the river in the towns of Norwich and Thetford, nearly to
Thetford village, making in all a length of about seven miles.

The only section of the Hanover." kame" which I have per-
sonally examined, is that on the road side between the bridge
and the village — the one figured by Upham on page 39 of his
Report. At this place, the riverward portion of the stratified
drift, or that spoken of by Upham as the " kame," is separated
from the following portion by a depression produced by under-
mining and a dropping of great masses to a lower level, and
consequently there are at this place two bluffs, the western
which is that of the so-called " kame," and an eastern, which is
referred by Upham to the ordinary terrace-formation. In his

464 J. D. Dana— "Karnes" of the Connecticut River Valley.

figure of the section of the kame here exposed to view, it is
made to consist of somewhat arched beds, with alternations of
coarse stony layers and finer material alike from top to bottom.
I found the bedding horizontal, like that of the eastern of the
bluffs ; its beds, composed. largely of sand and fine gravel, with
but few of cobble-stones ; and the top portion made of very
fine sand, identical in its light color, fine straticulation and other
features, with the top portion of the eastern bluff. The latter
bluff* differs in consisting throughout of stratified sand, and this
difference between the deposits near the river and those more
remote is not uncommon.

Prol 0. P. Hubbard, of the Medical School of Dartmouth
College at Hanover, and formerly Professor of Chemistry and
Geology in the Academic Department, has obtained for me the
following additional facts respecting the region of the supposed
u kame."

He states that no coarse gravel or cobble-stone beds exist along
the top of the ukame" south of the above mentioned section
for the half mile to Mink Brook, and none north of the same
for nearly a mile, so that this kind of evidence as to the exist-
ence of a " kame,'7 fails in these portions. Farther north,
above the village of Hanover, there is on the " kame " ridge an
area of cobble-stones, and two to three hundred yards beyond
this, across a deep cut leading to the river, a grass-covered
knoll made up of coarse gravel and cobble-stones, some of the
stones a foot or more in diameter. The knoll was found by
measurement to be fifteen feet high above the terrace-plain : it
marks the spot which is made by Upharo, the highest part of
the kame, 556 feet above mean tide level. Prof. Hubbard
ascertained with a spade that the knoll was composed of coarse
gravel, and rested on fine sand or sandy loam like that which
makes the top portion of the terrace-formation between there
and the village and also at the bluffs described above and else-
where. He coucluded, therefore, that the coarse cobble-stone
deposit was but 15 feet thick; and, from the level of the other
cobble-stone area, that the latter corresponded in position to the
lower portion of this deposit. In the deep cut between the
two cobble-stone areas the beds are not exposed, but no stones
show themselves, and the material was evidently of the same
fine sandy nature. Just sotith of the more southern area three
large excavations have been made on the east side of the
"kame" ridge to its top, for filling a bog, and these show
only sand ; but the northern is so near the cobble-stone layer
that some of the stones have fallen into it. The evidence
obtained by Prof. Hubbard thus appears to prove that the
coarse gravel of the two areas is only the top deposit of the
terrace-formation, such as characterizes in many other places
its river ward portion.

J. D, Dana — "Kames" of the Connecticut River Valley. 465

Norwich, Vermont. — The continuation of the Hanover " kame"
northward along the west border of the Connecticut in Nor-
wich, passes, near the end of its second mile, the valley of
Pompanoosuc Eiver. About a mile south of this turbulent
stream, a road ascends from the borders of the Connecticut Eiver
to the summit of the high terrace, crossing the "kame" where
its height is 565 feet (Upham), half a mile south of the highest
point, 600 feet. Along the road are sections of the deposits,
showing the inner nature of the Norwich " kame." Where the
road commences the ascent some cobble-stones lie scattered over
the surface, such as had been found common along the .road at
the base of the "kame" for the half mile or more to the south.
Above this, for the next hundred feet, there is sand, finely
straticulate, with occasional fine gravel. Nearing the top,
the beds become coarse gravelly, and then there are large
cobble stones ; and this upper coarse-gravel portion rises above
the general level of the plain, making a low ridge which is
the crest of the so-called "kame." In the higher part, to the
north, some stones, as stated by Upham, are 4 to 5 feet in di-
ameter and angular.

Nothing was observed on the ascent from the river, or on
the west side, to suggest a suspicion that this cobble-stone de-
posit was the top of a narrow range of coarse gravel beds bu-
ried beneath the terrace-formation ; on the contrary, the evi-
dence from the sections along the ascent, and especially the suc-
cession of beds toward the top from sand beds to gravel beds,
and then to the coarse cobble-stone gravel, strongly confirmed
the natural inference that all was one consecutive series, with
the cobble-stone deposit the uppermost and therefore the latest.
West of the cobble-stone ridge, or the " kame," the terrace has
great extent. The surface falls off immediately 40 feet, expos-
ing the materials that lie beneath, and these are sand and fine
gravel as on the east side.

The Pompanoosuc river was probably the chief source of this
coarse material of the summit. To the southwest, about the
village of Norwich, the terrace is quite stony over much of its
surface from the contributions to the terrace of Blood Brook.

In Thetford the " kame" becomes very low before the village
is reached.

The other reputed " kames" of the Connecticut Eiver valley
I have not particularly examined, But as the line from Wind-
sor to Thetford is " the kame of the Connecticut valley," essen-
tially " a continuous gravel ridge or kame, extending 24 miles,"
and is made, in Mr. Upham's work, the text for the description
of " kames" in general, details from the other minor "kames"
in the valley are not necessary for a right conclusion.

Am. Jour. Sci.— Thtkt> Series, Vol. XXII, No, 182.— December, 1881.

466 e/. D. Dana — "Kames" of the Connecticut River Valley.

Conclusion. — The conclusion from the investigation is, as al-
ready indicated, the following: that the supposed "kames" are
portions of the terrace-formation, with which they usually cor-
respond approximately in height ; and that their materials
were the same in source with the rest of the stratified drift,
and the beds the same in time of origin.

The gravelly character of the terrace- formation off the
mouths of the tributaries of the Connecticut is often mentioned
by Mr. Upham ; and, if the above conclusion is right, the coarse
material of the " kames" is to be explained on the same prin-
ciple. The position of these coarsest deposits, near the borders
of the flooded Connecticut, whether they make the lower or the
upper beds, is a consequence of the rapid flow of the waters in
this great stream, which drifted away much of the finer material
within reach and left stones. The coarsest stone beds at the
mouth of White River are located where the two streams — both
great streams then — join, that is, where the great contributor
of gravel and stones encountered the great distributor.

The deposit of gravel and stones in the upper portion of a
terrace I have attributed to the violence of the flood when at
its maximum stage. But in the region of the so-called
"kames," from Windsor to Thetford and beyond, floating ice
was probably needed for much of the transportation ; and ice-
floes would have been abundant at the time, when the glacier-
ice was in rapid process of dissolution about the slopes of the
Green Mountains — the range at the head of the principal trib-
utaries in this part of the Connecticut valley. At the same
time, the Connecticut, by its rapid flow along its eastern side at
one time and its western at another, would have determined an
accumulation of stony material along its borders, as a great
river now produces accumulations on its banks different from
those more distant. Here the floating ice with its burden of
earth and stones would have been stranded as well as other
transported materials. Moreover such deposits might have
been raised ten feet or more above the plain adjoining, as now
happens on large streams from modern floods. But there is no
occasion to account for a cobble- stone deposit along the whole
top of any of the so-called "kames;" for, only a small fraction
of each has a crest of this kind; or any difference in structure
from the ordinary terrace-formation, except that in some cases,
near tributaries, they have more of coarse gravel below.

In Haverhill the angular stones and gravel, brought down the
Ammonoosuc on ice-floes, made in one place a thick till-like
deposit lying unconformably over the stratified drift and con-
tinued some distance down the riverward slope of the terrace.
This is an exceptional case, due probably to the fact that the
White Mountains, the source of the stream, are near by.

J. D. Dana — "Kames" of the Connecticut River Valley. 467

But the ridge-like feature of many of these coarse upper de-
posits, on the riverward part of the terrace-formation, that is,
their standing up 15 to 60 feet above the level of the terrace
around, and sometimes higher, is in part, if not chiefly, due to
erosion. The Norwich stony deposit, on the top, south of the
Porapanoosuc, has a large and broad depression west of it; and
so has that south of White Eiver Junction, that of Hanover, and
others. Even the little knoll described on page 463 has its ad-
joining depressions, as shown in the figure there given, and the
gulch descending from the southern one of these depressions
may be a further consequence. The waters of rains, making
rills or streamlets, easily remove the sand and fine gravel of the
terrace-formation ; but they make comparatively little impression
on the beds of coarse gravel and cobble-stones, because of the
size of the stones and often also their partial consolidation by
iron oxide (limonite). Hence the waters which fall over the
stony surface find a place of descent and wear away on either
side ; and with every new inch of descent gained there is a gain
in fall and force, and a quickening of the work of erosion.
The channel begun is deepened and widened, waters from the
plain flowing in and helping in the removal : and thus broad
channels like river-channels may form over wide plains, and •
deep gorges be cut through to their depths if a place of dis-
charge is at hand. Besides, the river at the time of greatest
height swept over the terrace plains with often 40 to 60 feet or
more of depth, and large denudation in some parts would have
been the consequence.

The above explanations have reference to those so-called
" kames" examined by me in the Connecticut Eiver valley. I
make no sweeping application of them to those which have been
described from other regions that I have not seen. It was my
purpose to have studied, the past season, also the terraces of
the Merrimack valley, but time failed me.

The gravel ridges of the vicinity of Andover, Massachusetts,
first described by Prof. E. Hitchcock, and lately studied with
care and designated " kames" by Prof. Gr. P. Wright, appear to -
represent a phenomenon of a different' class. I had the guid-
ance of Prof. Wright in a day's excursion over them, and was
led to think, as he does, that these isolated ridges of unstrati-
fied coarse gravel and stones are of morainic sub-glacier origin ;
and, perhaps, lateral, though sub-glacier, moraines, left between
bodies of ice that moved southeastward along the depressions —
now marsh-filled — which exist either side of them. But without
more study of them, and especially of their relation to the de-
posits of the Merrimac valley, I would not express a decided
opinion on the question. •

468 C. 0. Bockwood, Jr.— Japanese Seismology.

Nothing has here been said with regard to the "kettle-holes,"
that is, isolated kettle-shaped and often pond-containing de-
pressions, which, in Mr. Upham's view, were connected in origin
with the u kames f and for the reason that they occur also over
ordinary terrace-plains. Further, Mr. Upham's hypothesis as
to the origin of u kames" there is obviously no occasion here to
discuss.

Some points in the explanations above advanced need, in
view of the difference of opinions among writers, further consid-
eration, and will be made the subject of another communication.

Art. LX. — Japanese Seismology;* by Professor C. G. Bock-

WOOD, Jr., Princeton, N. J.

The change in the foreign policy of the Japanese, by which
that country was opened to the influences of western civilization,
gave an impulse to several branches of scientific investigation
for which Japan affords special facilities ; but in no department
has there been more hopeful progress than in the study of
. Seismology.

The opportunities for the development of this science in Japan
are exceptionally good. Earthquakes are here quite frequent,
averaging for the whole kingdom more than one every day,
and sometimes far exceeding that number. Hattori has found
native records of 817 shocks in the fourteen months from Nov.
1, 1854, to Dec. 31, 1855. The earthquakes also are mostly of
moderate intensity and therefore better fitted for instrumental
study than those violent and destructive convulsions which leave
their record in ruined cities and decimated communities. The
centers of learning and science, where are naturally gathered
the greater number of persons qualified and disposed for such
investigations, are on the shores of Yedo 3ay, a district specially
subject to earthquake shocks and whose geological character is
tolerably well known. Here, in the capital Tokio, a society has
been formed for the especial study of Seismology, including in
its membership professors, both native and foreign, from the
educational institutions of the city, having as its president a
native Japanese, I. Z. Hattori, A.B. (Eutgers), and for its vice-
president Professor John Milne ; and which has printed, as the
result of its first year's work, a volume of Transactions amount-
ing to 188 octavo pages. Accounts of the work done in this
society and contributions from its members on topics related to
Seismology are also published from time to time in the Japan
Gazette.

* Read before the Princeton Science Club, Oct. 27, 1881.

0. G. JRockwoodj Jr. — Japanese Seismology. 469

In directing attention to those who have labored in this field,
we have to mention the names of E. Naumann, John Perry
and W. E. Ayrton, I. Z. Hattori, W. S. Chaplin, E. Knipping,
J. A. Ewing, G. Wagner, T. Gray and John Milne, all of whom
have added to the available stores of information, by the exam-
ination of native records, or by the invention and improvement
of instrumental appliances.

In the literature of Japan are found numerous accounts of
past earthquakes, reaching back even to 295 B. C, at which
time it is recorded "Fujiyama was upheaved." These native
records have been examined by Dr. Naumann,* Mr. Hattori,f
Mr. Knipping,J and Professor Milne,§ and have furnished
abundant material for discussion. Indeed the amount of Japa-
nese Seismological literature is unexpectedly large. Dr. Nau-
mann mentions the titles of thirty-three and Hattori o thirty-
four native books consulted in preparing their papers, while
Milne is acquainted with sixty -five native earthquake books
besides seven earthquake calendars. A part of this earthquake
literature, especially the calendars, has a scientific value, but on
the other hand much of it is made up of a series of anecdotes
often of a trivial character. For illustration of these, a single
one, selected from an account || of the great shock of 1707, will
suffice.

"HOW AN IMPETUOUS MAN FELL DOWN FROM UP-STAIRS."

" Five or six young men were singing and drinking up-stairs in
a tea house in Horiye. In the midst of their happiness they were
suddenly alarmed by the earthquake and at once became bewil-
dered. While one of them was looking out he missed his footing
and fell down from the ladder into a konomono-oke (a cask con-
taining radishes pickled in salt and bran which is very offensive
to the nose). The others who were yet up-stairs intended to
come down. But the man in the cask looking up said that below
all was chaos and it would be better to remain up-stairs. The
reason why the man below said that all was chaos was because he
had not perceived that it was by accident that he had fallen into
the cask."

The earthquakes contained in Naumann's and Hattori's lists
have been discussed by their authors and by Ayrton,^[ with

* Ueber Erdbeben und Vulcanausbruche in Japan. Mittheilungen der deutschen
Gesellschaft fur Natur- und Volkerkunde Ostasiens. 15tes Heft.

f Destructive Earthquakes in Japan. Transactions of Asiatic Society of Japan,
vol vi, p. 249.

X Verzeichniss von Erdbeben, wahrgenommen in Tokio, yon Sept. 1872 bis
Nov. 1877. Mittheilungen der deutschen Gesellschaft, etc., Ostasiens. 14tes
Heft.

§ Japan Gazette, June, 1881. •

(Milne in Japan Gazette, 1881.

If Note on the Periodicity of Earthquakes in Japan. Transac. Asiatic Soc. of
Japan, vol. vi, p. 320.

470 C. O. Bockwood, Jr. — Japanese Seismology.

respect to the seasons, the motions of sun and moon, the fre-
quency of sun-spots, meteors, eta ; and Professor Chaplin* has
examined in the same way the records for three years (1875-8)
of the Palmieri instruments in the Meteorological Observatory
of Tokio. But the results are entirely negative, not confirm-
ing Professor Alexis Perry's deductions from a similar exam-
ination of his lists, although Hattori and Ayrton both think
they find some indications of a periodicity in destructive
shocks.

Besides examining native records, much attention has been
given to the instrumental investigation of the earth -motion.
In this work Perry and Ayrton, Wagner, Chaplin, Ewing,
Gray and Milne have all had a part

The devices suggested by former observers have been here
tested anew. Pendulums long and short, suspended and in-
verted, with bobs light and heavy, and making their records
by scratching a smoked plate, by pushing light rods arranged
against them, or by pulling cords and turning pointers over
graduated arcs, the fluted mercury dish of Cacciatore, the
graduated cylinders of Bobert Mallet, and the bent tubes and
loaded springs of Palmieri, as well as the microphone sug-
gested by Bossi have all been employed and have done good
service.

But no one of these was entirely satisfactory. Not to men-
tion other difficulties, the pendulums and loaded springs had
each a normal rate of vibration, and were ready to take up
and accumulate earth vibrations of similar rate, while remain-
ing to a considerable extent unaffected by those of a different
period. So that the records of the earth-motion were compli-
cated or perhaps entirely concealed by those due to the normal
vibration of the apparatus. This difficulty, long known, was
stated and mathematically discussed by Perry and Ayrton in a
paper read before the Asiatic Society of Japan in 1877 and
afterward published. f The remedy suggested by them was to
support a heavy ball within an iron box, by spiral springs of
such stiffness as to make its normal rate of vibration much
quicker than any ordinary earthquake wave.

Moreover, while these instruments of former observers gave
some more or less accurate indication of the time of an earth-
quake shock, and of its direction of propagation and relative
intensity on some arbitrary scale, they afforded very little
knowledge of the extent or character of the actual motion of
an earth-particle, and to this end especially has tended the in-
strumental work of Japanese investigators. In this direction

* Examination of the Earthquakes recorded at the Meteorological Observatory
of Tokio. Transac. Asiatic Soc. of Japan, vol. vi, part II.

f On a neglected principle that may be employed in Earthquake Measurements.
London Phil. Mag., Y, vol. viii, p. 30, July, 1879.

0. Q. Hockwood, Jr. — Japanese Seismology. 471

was the attempt by Dr. Verbeck in 1873 to support a heavy
planed block of wood upon four crystal balls, these resting
upon a polished marble slab carefully leveled. The block was
then in neutral equilibrium and a pencil attached to it would
leave a record of the motion upon a paper fastened to the slab
beneath. Such a record was found to be too minute to be of
service, and an important aim of later devices has been to pro-
cure in some way an enlarged record of the earth motion. This
has been accomplished, in two ways : by employing an indicat-
ing lever with unequal arms, the shorter arm being acted on by
the motion of the earth, while the longer arm carries the writ-
ing style which makes the record, or by causing the earth-
motion, through the medium of a fine cord, to turn a small
pulley to whose axis is attached a long light pointer.

The earliest apparatus by which a magnified record was ob-
tained was Wagner's Pendulum Seismometer, first described in
a paper read before the German Asiatic Society of Tokio in
June, 1878, and printed in the Transactions of that Society.
After two years experience a full description of the apparatus
was published in the Japan Gazette (July 10, 1880).* It con-
sists of an iron ball weighing forty or fifty pounds, suspended
by a bundle of silk threads three feet long. At the moment
of a shock this heavy ball by its inertia remains stationary.
Beneath the lowest point of the ball, a light vertical indicating
lever or pendulum is supported by a bar rigidly connected with
the earth. The fulcrum of this indicating lever is formed by
a metallic sphere £ inch in diameter, on which it rests by a
smooth plate forming the top of a short hollow cylinder of the
same internal diameter as the metallic sphere. The point
about which this lever pivots is therefore the center of this
small supporting sphere. The upper end of this lever, the
shorter arm, engages with a similar small sphere attached to
the lower part of the heavy iron ball ; while the lower and
longer arm is attached to a light thread that passes through a
hole in a porcelain plate. Of course any motion of the ground
is transmitted to the support of the indicating pendulum and
causes relatively magnified motion of the lower end of the
same the amount of which is indicated by the length of thread
drawn through the hole. It appears to the present writer that
the elasticity of the silk cords supporting the heavy ball would
introduce an element of uncertainty into the indications of this
apparatus, as quantitative results could be hoped for only on the
assumption that there was no vertical motion of the heavy ball
with respect to the support of the indicating pendulum. Of
course this seismometer gives indication of the amount of hori-
zontal motion only. The direction must be obtained from other

# Transactions Seismological Society of Japan, vol. i, part I, p. 54.

472 C. O. Boctwoodj Jr. — Japanese Seismology.

apparatus used in connection with this, as most also the vertical
component

Another device for obtaining a magnified record of the earth-
motion is Grays Boiling Sphere.* This consists of a heavy
lead or iron sphere resting in neutral equilibrium upon a level
plane, and therefore free to roll in any direction. Above the
sphere an indicating lever is supported in a vertical position,
by a sort of spring universal joint, so that its lower extremity,
the shorter arm of the lever, engages with a hole in the highest
part of the sphere, while its upper and longer arm carries the
recording style. The method of arranging the fulcrum of this
lever is peculiar. The light rod forming the lever passes cen-
trally through a small disk to which it is fastened. This disk
plays within a horizontal ring, from which it is supported,
through the medium of four bent springs, which are attached
by one end to symmetrical points on the ring and by the other
to the edge of the disk. The lever has a small weight on its
lower arm sufficient to bring the center of gravity below the
fulcrum and to make its normal rate of vibration slower than
that of the earthquake. The lever supported in this way is,
by the elasticity of the springs, free to move in any direction
as influenced by the motion of the heavy sphere.

Gray's Double Bracket Seismograph f also gives a magnified
record of the actual motion of an earth-particle. This consists
of a post planted firmly in the ground, to which is hinged, by
its longer side, a light but strong frame, something like a gate,
measuring 60 X 15 centimeters. The upper hinge is a knife
edge in a ring, while the lower is a point resting in a conical
socket. To the outer edge of this frame is hinged in the same
way another similar but somewhat lighter one, loaded on its
outer part by a thick metal disk of considerable weight, which
by virtue of its inertia forms the stationary point of the seismo-
graph. When ready for use the planes of these two brackets
are placed at right angles to each other, and each makes an
angle of forty-five degrees with the face of the post. The
record is made through the medium of an indicating lever sim-
ilar to that above described with the rolling sphere, and sup-
ported below the center of the heavy disk by an arm extending
out from the post.

Gray's Pendulum* Seismometer aims to record the earth-
quake motion by means of its components in three directions at
angles of 120°. It consists of a heavy weight hanging by a
cord three feet long, from the middle of a stretched wire. It is

* On Instruments for Measuring and Recording Earthquake Motions. London
PhiL MagM V. toL xii. p. 19*. Sept- 1SS1.

f London PhiL Mag.. V. toL xii. Sept~ 1S81.

♦ Transactions of Seismoiog. Soc of Japan. toL i. part I, p. 44 ; also Lond.
PhiL Mag- V. toL xii Sepc 1SS1.

C. G. Bockwood, Jr. — Japanese Seismology. 473

thus able to move in a vertical as well as a horizontal direction,
and the amount of this vertical motion is recorded by attaching
to the upper part of the pendulum a fine thread which turns a
small pulley above and thereby moves a long pointer. To
register the horizontal motion, three radiating cords pass from
the center of inertia of the heavy bob of this pendulum to
three horizontal pulleys to which are attached long pointers
that magnify the actual motion twenty-five times. The method
of attaching these pointers to the pulleys is new and ingenious.
The pointer is hung to the under side of the pulley by a bifilar
suspension, bo that there is no tendency for the inertia of the
pointer to carry the pulley too far, as was found to be the case
if they were rigidly attached. The inventor proposes to pre-
vent the pendulum from accumulating earth vibrations that
may happen to synchronize with its own normal rate, by allow-
ing a pointed rod to slide on a glass plate below the bob and
weighting this sufficiently to produce the necessary friction.
• In Ewing's* Pendulum Seismograph this same object is
accomplished by using a pendulum twenty-one feet long, so
that its normal time of vibration is about five seconds, much
longer than any earthquake vibration. The bob of this pendu-
lum, which has been erected in the University of Tokio, is a
cast iron ring, whose section is 2 X 4 inches and internal diam-
eter lftj inches,' and which is suspended in a horizontal posi-
tion from the top of a firmly braced framework. This heavy
ring is crossed by a diametral bar, at the middle of which are
applied the short arms of two bent levers, whose long arms
mark upon circular smoked glass plates, caused to revolve con-
tinuously by clockwork. The planes of these two bent levers
are placed at right angles to each other, and they are supported
by gimbal joints in such a way that each is affected by motion
in one direction only. The horizontal motion of the pendulum
bob is thus separated into two rectangular components which
are recorded separately.

Another device which records the two components of the
earth motion separately is Gray's f Rolling Cylinder Seismo-
graph. Here a pair of exactly similar hollow cylinders of
metal are placed on a smooth level plane, with their axes hori-
zontal and at right angles. Being thus in neutral equilibrium
they are free to roll, and their motions are recorded by the
magnifying levers whose fulcrums are upon a fixed support
above the cylinders and whose long'arms write upon a moving
drum or plate.

Still another arrangement, the Bracket Ring Seismograph,
which has already done good service, is a modification of Zoll-

*A new form of Pendulum Seismograph. Transactions Seismolog. Soc. of
Japan, vol. i, part T, p. 38.

f London Phil. Mag., V, vol. xii, Sept., 1881.

474 C. O. Rockwood, Jr. — Japanese Seismology.

ner s horizontal pendulum, due originally to Chaplin and im-
proved by Ewing and by Gray. It consists essentially of a
weight supported on a horizontal bar, which is attached at
one end to a vertical axis and at the other end carries a lone
pointer writing upon a moving plate. This will of course
record only one component of the motion, viz : that at right
angles to the direction of the pointer, and such apparatus must
be used in pairs placed at right angles to each other.

The apparatus for vertical motion, which was used in connec-
tion with this, was a vessel of water supported from above
and having a flexible bottom, which would be acted upon by
the inertia of the liquid and would make its record by a multi-
plying lever upon a moving plate.

A modification of the conical pendulum by Gray * promises
to afford a very sensitive seismograph but it cannot well be de-
scribed without diagrams.

Milne's tremor indicators + are also most delicate and sensi-
tive. From a rigid frame is suspended, by a short wire, a
heavv mass, against the sides of which rest two small hori-
zontal bars of wood. Under the outer end of each bar a small
mirror is hung by a bifilar suspension, one thread to the bar
and the other to an adjacent fixed point Then any motion of
the heavy mass relative to its support causes motion of the
bars, and so of a beam of light reflected from the mirrors. A
motion of l0%66 of an inch is readily detected in this way.

Numerous other devices are described in the Transactions of
the Seismological Society of Japan and in the other papers
above referred to, and to these sources the reader is referred
for further information in regard to them.

We are now to consider some results obtained by the use of
instruments and the discussion of their records. The published
volume of Transactions of the Seismological Society, Part II,
contains from the pen of John Milne, a long account, amount-
ing to over one hundred pages, of the earthquake of February
22, 1880. It is based on one hundred and twentv written com-

/ ml

munications received by the author, of which thirty were
detailed replies to a series of printed questions. Our limits
forbid anything more than a brief statement of a few selected
points.

The 'direction of the shock was deduced from personal
reports and from the indications of Palinieri's instrument, a
Cacciatore and a pendulum recording its motion on a smoked
glass. The general result was that there had been two shocks,
the first in a direction approximately to or from N.N.W., the

* London Phil. Mag.. 1. c.

+ See paper "On Recent Earthquake Investigations," by T. Gray in Chrysanthe-
mum, vol. l. No. 5. Ma v. 1881.

C. G, Rockwood, Jr. — Japanese Seismology. 475

second N.N.E. or N.E. It is interesting to note that the pend-
ulum records of the Luzon* earthquake of July, 1880, show
likewise the presence of several wave directions in azimuths
not widely different from those here stated.

Again, not only were many chimneys and similar objects
overturned, but in numerous instances chimneys and monu-
ments in the cemeteries were twisted upon their bases, some-
times through an angle of 20° or 30°, without being overthrown.
The rotation was usually but not invariably in a direction con-
trary to that of the hands of a watch. As to the cause of such
rotation, Mallet's explanation, which attributes it to the verti-
cal through the center of gravity not coinciding with the center
of friction, is rejected as not in accord with the great prepon-
derance of rotation in one direction, and another explanation
suggested by T. Gray is offered, to this effect : If any columnar
object having a rectangular base is acted upon by a force
parallel to either side or to either diagonal of the rectangle, it
will tend to overturn without rotation. If, however, the force
has any direction other than these, there will be a tendency to
rotation in a direction determined by the relation of the line of
force to that diagonal which lies nearest to it. If the rectangle
be divided into eight equal triangles by the two diagonals and
two medial lines parallel to the sides, and the alternate trian-
gles be shaded, it will be seen that the rotation will be in one
or the other direction, according as the direction of the force,
falls in a shaded or an unshaded triangle. The direction in
which a stone is found to have been twisted will then enable
us to assign limits to the direction from which the impulse that
moved it must have come, and will thus serve to indicate the
direction of the earthquake shock. With regard to the earth-
quake in question, the direction inferred in this way from the
numerous twisted grave-stones, agrees in general with the
instrumental indications noted above.

This earthquake was sensibly felt over an area included
within a radius of one hundred and twenty miles. From the
directions of the shock as observed at Tokio and Yokohama,
and from other considerations, the author concludes that the
probable origin of this earthquake was nearly equidistant from
Tokio and Yokohama, but somewhat to the east of them, under
the eastern shore of Yedo bay. Indeed many of the recent
earthquake^ in Japan seem to come from that region. The
geological characteristic of that district is beds of volcanic tufa
and breccia very much faulted and contorted in the southern
part and giving evidence of recent elevation. It is in the
prolongation of a long line of volcanoes and volcanic islands,
extending 1,500 miles southward into the Pacific through the
Bonins ; and it is also on another line of volcanoes, 3j000 miles

* This Journal, III, vol. xxi, p. 52, January, 1881.

476 C O. Rod-wood, Jr. — Japanese Seismology.

long, extending from Kamschatka to the Philippines. The
suggestion is ventured then that this and other earthquakes are
to be attributed to action taking place about the end of the
fissure in the earth's crust, marked by the first mentioned line
of volcanoes, of which Ooshima. sixty miles south, is the nearest
active vent; "that this line is still endeavoring to open for
itself vents still farther north ;,T and u that beneath Yedo bay
there is a point where volcanic agencies are endeavoring to
force a way."

These conclusions as to the probable origin of the frequent
earthquakes are further confirmed by later observations of two
different sorts.* Prof. Milne in Tokio. and Mr. W. EL Talbot
in Yokohama, have made careful time observations, using
clocks with sensitive apparatus to stop them at the instant of a
shock and keeping the clocks regulated by daily telegraphic
comparisons. The result is that the shocks are usually felt in
Yokohama from fifteen to thirty seconds earlier than in Tokio,
indicating an origin nearer to the former place. Again seis-
mometers were placed at Tokio, at Yokohama and at Kisaradzu
on the opposite side of the bay, with special reference to deter-
mining the direction of the shocks, and gave the following
results. On Jan. 7, 1881, the directions intersect within tun
miles of Yokohama ; on Jan. 22, 1881, the intersection was
four miles south-southeast of Yokohama ; and on Jan. 24, 1881,
the intersection was seven miles south -south west of the same
place, — again all indicating an origin near Yokohama.

But perhaps the most interesting of recent results was ob-
tained from the earthquake of March 8, 1881, some notesf on
which were read before the Seismolo^ical Society on March 23d.
by Prof. Milne. At this shock a complete record of the earth-
motion for over twenty-five seconds was secured. The instru-
ments used were a pair of "bracket ring7' seismographs, writing
upon a slip of smoked glass, for the two horizontal components,
and a water vessel with flexible bottom for the vertical compo-
nent. The bracket-ring machines (No. 1 and No. 2), were
purposely placed so as to record vibrations at right angles to
and in the direction of a line joining Tokio and Yokohama
(S. 23° W>

No. 1 showed a decided motion, there being about seven
vibrations in five seconds, or one complete vibration in \ of a
second. The greatest indicated motion in this direction is
about 1'3 millimeters.

No. 2 indicated very slight but sensible motion.

No. 3 for vertical motion showed about six distinct waves in
a space indicating twenty -five seconds of time.

These records, confirmed as they are by the register of Pal-
mieri's instrument and of eleven different pendulums, show

* Japan Gazette, Feb. 5r 18S1. \ Japan Gazette, April 2, 1881.

C. G. Rockwood, Jr. — Japanese Seismology. 4t77

clearly that the main vibration in the vicinity of Tokio was in a
general east-and-west direction. The time observations, and
other considerations also, indicate that the origin of the shock
was in the faulted region near Yokohama. Hence Milne is led
to the conclusion that the vibrations observed were transverse
to the direction in which the wave was moving, instead of
normal as usually supposed; and that the wave, at least by the
time it reached Tokio, was one of distortion, not of compres-
sion. It is probable that in any ordinary earthquake both
sorts of wave are coexistent, at least near its origin ; but experi-
ments made by Milne upon artificial shocks produced by the
fall of a heavy weight, tend to show that the transverse vibra-
tions are the more persistent and are felt to a greater distance
than the longitudinal. Moreover, if the earthquake wave orig-
inated by the tearing open of a fissure in the rock and the
sliding of the surfaces upon each other, a shearing force would
be exerted which might produce a wave of distortion without
any accompanying wave of compression.

The Japan Gazette of July 23, 1831, contains a note of some
interesting observations on an earthquake of July 5, 1881,
showing that the motion of the ground varied considerably in
direction during the same shock. The records were made by
Gray's Double-bracket Seismograph writing upon a smoked
plate. Prof. Milne says :

"Near to the commencement of the shock the motion was
N. 112° E. One and a half seconds after this the direction of
motion appears to have been N. 50° E. In three- fourths of a
second more it gradually changed to a direction N. 145° E. ;
and after a similar interval to N. 62° E. Half a second after
this it was N. 132° E., and four seconds later the motion was
again in the original direction, viz., N. 112° E. There appear
to have been at some portions of the shock not more than four
vibrations per second, at other portions there may have been as
many as ten. The greatest amplitude of motion does not
appear to have reached one millimeter."

The records of the various instruments agree in the indica-
tion that the amplitude of vibration of an earth -particle, at
least in such shocks as ordinarily occur in Japan, is much
smaller than has generally been supposed, not more than a very
few millimeters. Of twenty earthquake shocks observed by
E. Knippin£ * with Dr. Wagner's apparatus only two exceeded
2*5 mm. in amplitude, and a similar fact has been incidentally
mentioned in respect to several of the earthquake shocks
spoken of above.

To conclude our revifew of what has been done in Japan in
this department of research, the results achieved can perhaps
best be summed up in the words of Professor Milne himself in

# Transactions Seismolog. Soc. of Japan, vol. i, part I, p. 71.

478 C. G. Bock wood, Jr. — Japanese Seismology.

his report to the British Association at its recent meeting in
York, where he states them thus: —

" 1st. The actual back-and-forth motion of the ground is
seldom more than a few millimeters (usually not equal to one
millimeter) even though chimneys have fallen.

a2d. The motion usually commences gently but is very
irregular.

14 3d. The number of vibrations per second usually varies
between three and six.

"4th. During one shock the direction may be irregular.

u5th. East and west vibrations as recorded at Yedo (Tokio)
have in some cases been shown by time observations to have
traveled up from the south.

"6th. Many of the shocks which visit Yedo appear to have
come from a district which is much faulted, and which gives
evidence of verv recent elevation."

This brief and no doubt incomplete survey of the field con-
sidered gives reason to believe that the knowledge of the phe-
nomena and causes of earthquakes has received and will receive
important additions through the labors of these residents of
the far east ; and that this youngest of the scientific societies of
Japan, whose exhibition of seismographical instruments at-
tracted 2,000 visitors in one day, has such a hold upon the
interest of that community that it will not be left without sup-
port even though all its foreign members should be withdrawn
from the country.

In conclusion I desire to say that for much of the information
embodied in this paper I am indebted to the kindness of Prof.
John Milne of the Imperial College of Engineering in Tokio.

Note. — Since this paper was written, the November number
of the London Philosophical Magazine has come to hand, con-
taining an article of 22 pages by John Milne and Thomas
Gray, on " Earthquake Observations and Experiments in Japan/'
It is a resume of work done by the authors during their resi-
dence there, and consists of two parts, the first devoted to a
description of the instruments used, the second to a discussion
of the Earthquake motion. The instruments are described
under the head of 1. Seismoscopes ; 2. Seismometers and
Seismographs ; 3. Instruments for vertical motion ; 4. Appa-
ratus on which to record earthquake motions; 5. Time-takers.
In the second part, the authors discuss the relation of the
normal and transverse vibrations, the details of the movement
as illustrated by a copy of the instrumental record made by a
pair of conical pendulums on July 25th, 1881, the relative
frequency of earthquakes at different seasons, the effect on
buildings, and the rotation of bodies. c. a. r.

Princeton, Nov. 17, 1881.

A. W. Wright — Distillation of Mercury in Vacuo. 479

Art. LXI. — An Apparatus for the Distillation of Mercury in

Vacuo\ by Arthur W. Wright.

The importance of pure mercury in many of the operations
in the laboratory makes a simple and efficient means of free-
ing from its impurities the ordinary commercial metal, or that
which has become fouled by use, an object greatly to be de-
sired. The familiar chemical methods, aside from their incon-
venience, are not entirely satisfactory, and often leave the con-
dition of the product uncertain. Distillation in the usual way,
in retorts open to the air does not prevent contamination by
oxidation, and the purity of the metal is further endangered
by the liability to spurting and the possible presence of sub-
stances volatile at the boiling point of mercury. When the
process is conducted in a vacuum, however, these drawbacks
are avoided, and a perfectly pure product is obtained.

A very elaborate and complete apparatus for this purpose
has been devised by Professor Weinhold,* which fully satisfies
all the conditions of the problem. This instrument has pro-
visions for the maintenance of the vacuum by means of a
Sprengel pump which constitutes a special part of it, with
suitable arrangements for adjustment of the mercury supply,
the heat from the gas burner, and the like. The devices for
securing these objects, however, render the apparatus some-
what bulky, and complicated in structure. A far simpler con-
struction has been employed by Dr. L. Weber, f which how-
ever has no contrivance for maintaining or renewing the exhaus-
tion, except by refilling with mercury, and otherwise leaves much
to be desired. Its consists essentially of a long glass tube bent
into a U-shape so that when filled with mercury and inverted
with the ends of the tubes in vessels containing mercury it forms
a double barometer, the bend of which is above the level of the
metal and therefore vacuous. An enlargement at one side
where the heat is applied by a small Bunsen flame gives an
increased surface of evaporation. The mercury vapor con-
denses in the upper portion of the empty space and flows out
through the other branch of the tube.

The apparatus devised by the writer is based upon Weber's
plan of a double barometer tube, but with important modifica-
tions which secure substantially the advantages of the more
complicated system of Weinhold. The most essential portions
of it are represented, in section, in the accompanying sketch,
which is drawn to a scale of one-tenth that of the instrument

* Carl's Repertorium fur Physik, vol. xv, p. 1. f Ibid., vol. xv, p. 52.

480 A. W. Wright — Distillation oflfercury in Vacuo.

iteelf. The principal member of the still consists of a single
continuous piece of gloss work, which, for convenience of
description, may be regarded as made up of several distinct
parts designated by the letters b, c, d, e,f, g, k.

The portion b is a straight, rather heavy piece of tubing, of
about one centimeter exterior, and five or six millimeters in-
terior, diameter. Its length is a little more than 76 centi-
meters. It is open at the lower extremity, and at the
other is enlarged to an oval bulb, c, about 85 mm. in diameter
and 120 mm. long. At the upper end of this is joined tbe por-
tion d, e, having an interior caliber of about 15 mm. Tbe ver-
tical portion next to cis 25mm., the inclined portion, d, 130 mm.,
and the sloping part, e, 300 mm. in length. The object in
making d so long aud giving it the inclined position was to

A. W. Wright — Distillation of Mercury in Vacuo. 481

prevent any globules of mercury thrown up from the bulb
entering the portion e. But it might well be somewhat shorter,
as with proper care in the application of the heat no shocks
of the mercury in boiling ever occur.

Toward the end of e the glass is narrowed, and, at the angle,
it passes to a continuation #, which is a straight, vertical tube
having an interior diameter of about one millimeter. The
angle is so formed that the globules of mercury running down
from e fall freely into g without accumulation at any point.
This part of the apparatus is in fact a Sprengel pump, and the
mercury as it passes out maintains the exhaustion of the whole
tube at a very high point A small tube, / serves to make con-
nection with the air-pump at the beginning of the operations.
The tube g, at its lower end, A, is bent upward and a small bulb
blown upon it, sufficiently large to hold enough mercury to fill
g itself. Above the bulb the tube is bent into a horizontal
direction, this part being 30 or 40 millimeters long, and then
directly downward, forming the outlet for the mercury. The
total length of g is 90 centimeters.

A cistern, a, serves for the reception of the metal to be
operated upon. It is a wooden box 150 mm. square, and about
60 mm. deep. The joints are carefully fitted and the wood
oiled and then well varnished, being thus rendered quite im-
pervious! A small well, 80 mm. deep, for the reception of the
end of the main tube, is made by inserting a thick glass tube
in the bottom of the box. This arrangement, with the large
area of the cistern, increases the range of adjustment of the
latter, and makes it possible for several kilograms of mercury
to pass through the apparatus before any such alteration of
level in c is produced as to require a new supply, or a read-
justment

The glass tube and cistern are mounted upon a light wooden
frame, the weight of the former with its contents being chiefly
sustained by an iron ring which touches the bulb some distance
below its widest part. Several layers of fine wire gauze care-
fully fitted to the lower half of the bulb are interposed be-
tween it and the ring, forming an elastic bed, and serving also
to distribute the heat. A cylinder of thin sheet copper just
large enough to slip through the ring is supported upon the
latter by a narrow flange at the top. It extends downward
about 60 mm. and is pierced with a number of holes just be-
neath the ring. It serves to direct the heated current from the
burner upon the bulb, as also to protect the flame from move-
ments of the air, and render it steady in its action.

The heating apparatus consists of a hollow ring having upon
the upper surface 12 holes 25 mm. in diameter, spaced uni-
formly in a circle of 25 mm. radius, and concentric with the

Am. Jour. Sol— Third Sbbibs. Vol. XXII. No. 182.— December. 1881.

482 A. W. Wright — Distillation of Mercury in Vacuo.

glass tube which passes through it. The ring is fitted to the
top of a common Bunsen burner, and the whole moves upon a
vertical slide, with a clamp screw, by which it may be fixed at
any point desired. It has been found advantageous in practice
to use but six of the openings, and these all upon one side.
A conical hood of sheet copper encloses the upper half of the
bulb, and is prolonged by a tube of the same material, which
covers the glass tube as far as the angle above d. The lower
edge of the hood is at nearly the same level as the top of the
cylinder above mentioned, and is about six centimeters wider
than this, so as to project laterally some three centimeters all
round. The upper portion of the copper cone and tube are
wide enough to leave an interval of five or six millimeters
between them and the glass. The heated gases from the holes
in the cylinder, streaming through this space, envelop the bulb
c and tube d, thus preventing condensation of the mercury
vapor before it reaches e.

The cistern is mounted upon a vertical slide with a clamp
screw, and can be moved up or down, the range of motion be-
ing about six centimeters. This makes it possible always to
bring the mercury to the proper height within the bulb, and to
suit the adjustment to the varying atmospheric pressure.

The apparatus is put in operation as follows: Connection
having been established with a Sprengel air-pump by means of
the tube/ mercury is poured into the cistern so as to cover the
bottom of it to the depth of a centimeter or two. If pure mer-
cury is at hand the bulb at h may be filled with it, if not the
extremity of the outlet tube is sealed or otherwise tightly
stopped. As the exhaustion proceeds the mercury rises in 6,
finally reaching c, and if all the air were removed, it would
stop at the barometric height above the surface in the cistern.
The latter is adjusted so that the top of the column is a little
below the center of the bulb, c. When no more air can be with
drawn by the pump, /is sealed with a gas flame and the con-
nection with the pump severed. The apparatus is thus exhaus-
ted once for all, as subsequently it maintains the vacuum by its
own operation. The burner, previously set some distance below
the bulb, is now lighted and the flame made very small at first
The mercury soon becomes heated, vapor is formed, and after a
time drops begin to fall from the interior surface of the bulb
and tube above it. The flame is slowly increased and raised,
until, in fifteen or twenty minutes, the vapor passes the angle
at the top and begins to condense in e. As the globules of
mercury fall into g they carry with them the residue of the air,
gradually filling the bulb at A, and later the tube g itself. The
point of the tube at h is now unsealed or broken off, and the
mercury issues drop by drop into a vessel placed to receive it.

A. W. Wright — Distillation of Mercury in Vacuo. 483

The operation now proceeds continuously, and the apparatus
requires scarcely any attention, further than to keep the cistern
properly supplied with mercury, and to remove the pure metal
when necessary. The residual air is quickly removed from the
tubes by the pumping effect in g, and after a short time each
drop falls with a sharp click in the tube. The construction of
the part h makes it easy to obtain pure mercury from the very
beginning of the operation, an advantage not furnished by the
other forms of the apparatus mentioned.

In adjusting the height of the cistern, a, allowance must be
made for the tension of the mercury vapor in the upper portion
of the tube. The cooling effect of the condensing tube, e, is
such that this is usually from four to six millimeters, and it
rarely or never exceeds one centimeter. The temperature of
vaporization corresponding to the latter tension is less than 180°,
as, according to Eegnault's results, this is the temperature at
which the vapor has a tension of eleven millimeters. The low
temperature is of itself a matter of importance, both as regards
economy iu the application of the heat, and as diminishing the
probability of volatilization of any substances which the mer-
cury may contain as impurities.

The apparatus here described, when in use, consumes from
one-third to one-half the amount of gas required for an
ordinary Bunsen burner. The mercury does not come into
active ebullition, but vaporizes quietly and entirely without
shocks. The rate of distillation varies of course with the heat
applied, but is from four hundred to four hundred and fifty
grams per hour. After the burner is once adjusted the appa-
ratus requires no attention and may be left to itself for hours,
care being taken that the cistern contains sufficient mercury.
When out of use the tubes are left with the mercury in them,
remaining thus exhausted and ready for use at any time.

As the mercury in the bulb and the tube b retains all the
impurities left behind in the process of distillation, these may
at length accumulate in such quantity as to interfere with the
proper operation of the apparatus, and to necessitate their
removal. This is not likely to occur for a long time unless the
mercury used is excessively impure. But when the removal is
indispensable it may be effected either by opening f, allowing
the mercury to descend into the cistern and thus be withdrawn,
then refilling and exhausting as at first; or more simply by
lowering the cistern until the mercury sinks below the bulb, in
which case all but the small portion contained in b will run out
into the cistern and can be drawn off by a siphon or otherwise,
care being observed that it is not carried so low as to allow of
the admission of air at the bottom of the tube.

The apparatus in operation has proved entirely satisfactory

484 Scientific Intelligence.

in every respect, and extended use of it in the laboratory has
suggested no modification. As mounted upon its frame it has
a height of about 125 centimeters, and the base covers a space
forty-five centimeters long and thirty -three wide. It is so light
that it may readily be lifted and carried with one hand. The
glass work was very skillfully constructed, after the design of
the writer, by Mr. W. Baetz, of 96 Fulton street, New York City.

Yale College, Nov. 14, 1881.

SCIENTIFIC INTELLIGENCE.

I. Physics and Astronomy.

1. Dynamo -Electric Machines. — Sir W. Thomson concludes
from a simple mathematical analysis of the currents in a dynamo-
electric machine, giving a continuous current, that the formula

E = /y/RR' holds ; in which E is the resistance of the exterior
circuit and RR' are the resistances of the field magnets and the
revolviug bobbins. If r represents the ratio of the total work to

the lost work and e = ^- the formula r = 1 -f 2,y/f results. The

case considered is that of a dynamo-electric machine provided
with a shunt circuit. — Comptes Rendus, No. 12, September, 1881,
p. 474. j. t.

2. Rotation of plane of Polarization of Light by the Earth? &
Magnetism. — M. Henri Becquerel states as the result of his ex-
periments that the rays D traversing horizontally a column of sul-
phide of carbon of lni in length in a direction parallel to the mag-
netic needle, undergo at the temperature of 0° C. under the in-
fluence of the earth's magnetism at Paris, a magnetic rotation of
0'*8697. The direction of this rotation is from right to left for an
observer reclining horizontally with his head toward the north.
This number constitutes a natural constant by which we can con-
vert into absolute measure the determinations of the magnetic
rotations of the plane of polarization of light, and by which we
can express the intensity of a magnetic field in terms of the rota-
tion to which it gives rise. In the C. G. S. system, the above re-

suit is expressed by 1*31 ,< 10 which denotes the magnetic rota-
tion of the D lines in a magnetic field of strength unity, between
two points at a distance of unity. — Comptes Rendus, No. 12,
September, 1881, p. 481. j. T.

3. The value of the Ohm. — Lord Rayleigh and Schuster have

redetermined the ohm by means of the original apparatus used

by the Committee of the British Association and have obtained

pfl/rth o uadrant

the value 0,9893 - . — Proc. Roy. Soc, xcii, pp. 104-

' sec. * rr

141, 1881. j. T.

Geology and Natural History. 485

4. JOphemeris of the Satellites of Mars. — The following tables

five a portioD of the ephemeris, calculated by Professor H. S.
BrrcHETT, including opposition time and the time of nearest ap-
J roach. Table I gives the times of east and west elongation for
teimos, that for Dec. 13 and the alternate below being West, and
the others East ; table II gives the times of west elongation for
Phobos. The effect of aberration (not included) would make the
satellites about five minutes late at each elongation.
I. Dbimos.

Due

\YT

?>;;,

,.,.,.

",.'■,'

p™.

ma.

1 >■■■-.

21 19

12 2T
3 as

18 13
9 Bl
0 69

1C 7
7 15

22 2a

13 31

"'«

B3'-2

20 "
31

23
2a

23
24
26
SB

■n

19 4?
ID B4
2 2
IT 10

S 19

23 sa

11 33
5 1L
30 49
]] 6T

[..■,-.

27
28
39
•2»
30
30
31

18 12
9 20
0 28

IB 36
t> 44
21 62
13 0

4 7

19 IB

216-9

as-t

3"t"

»i

-■

M*V

—

n, .
.-■'

■:

r.
■n
■:•;
M
;■>

.'■

w«>.

"""

D«.

6 31
13 10
20 49

3 28
12 7
19 16

3 2f>
11 4
18 43

2 33
10 3
IT 41

1 SO

8 69
16 38

0 17

7 66
1ft 36
23 14

6 63

18
20
20
20
21
VI
■->!

22
Tl
■:•
23
23
23
?*

:■
-j i
;■■
■;..

■'■

2! 12
B 61
13 30
21 9
1 48
12 27
20 6

1! 23

19 4
3 43

10 22

15 1
1 40
9 ID

16 BS
0 37

16 65
23 34

14 63
22 32

C LI
13 60
21 29

6 9
12 47
20 16

11 44
19 23

218'6

3 If.

1491

.'I -

:iu
31
:u

IS 21
2 0
19 39

0 67

2460

247 3

II. Geology and Natural History.

1. Geological Survey of Pennsylvania. — The following vol-
umes have recently been issued at Hairisbnrg r

Report of Progress in Jefferson County (numbered H6), by
W. G. Plait, 219 pp. 8vo, with a colored map of the county.

486 Scientific Intelligence.

Third Report of Progress in the Laboratory of the Survey at
Harrisburg (numbered M3), by A. S. McCbeath. 126 pp. 8vo,
with a map.

The Geology of Erie and Crawford Counties (numbered Q4),
by I. C. White. 406 pp. 8vo. Includes a paper on the Discov-
ery of the Preglacial Outlet of Lake Erie by J. W. Spknceb,
Ph.D., with two maps.

The Geology of Blair County (numbered T), by Fbankle*
Platt. 312 pp. 8vo, with Atlas.

The volumes all bear evidence of good work, both in the scien-
tific .and practical direction.

Mr. McCreath's Laboratory Report contains numerous analyses
of iron ores, coals and cokes, and limestones, with some of fire-clays.
Many of the iron ores are from beds of limonite associated with
Lower Silurian limestones. The limestone formation No. 2 (or
the Calciferous and Chazy), wherever found in Pennsylvania, is
stated to have associated with it more or less important deposits
of this iron ore, some of them at the bottom, others at the middle,
and others at the top beneath the Trenton limestone ; and these
beds have supplied the larger part of the stock to the furnaces
along the Lehigh, Schuylkill and Susquehanna rivers, and the
whole of it to the furnaces of Mountain Creek Valley, in Cumber-
land County, and some others. They occur at intervals in the
Cumberland Valley, from the Lehigh River to Maryland, and
through Virginia and East Tennessee to Alabama. Other iron
ores analyzed were from Magnetite mines near Dillsbury, in
York Co., connected with the Mesozoic sandstone, and still others
from Devonian and Carboniferous rocks, and from bogs. The
Cumberland Valley ores contain '018 to 1*787 per cent of phos-
phorous, but usually under 0*5 ; and they sometimes vary in this
respect 0*21 in the same bed.

In the Report on Erie and Crawford Counties Mr. White men-
tions facts respecting " buried valleys." He states that " the
present water-courses meander along the upper surfaces of drift
deposits which fill the ancient valleys to various heights above
the old rock-beds." About four and a half miles below Meadville,
in the valley of French Creek, a boring went down 285 feet
through the drift from a level 482 feet above Lake Erie. Cou-
neaut Creek has a drift-filling, according to borings, 180 feet deep.
Other similar facts are reported. Conneaut Creek is the only one
of the streams that now takes water to Lake Erie. The author
refers to similar facts described in the Report of Mr. J. F. Carll,
and cites his conclusion that the buried water-ways drained
northwestern Pennsvlvania toward Lake Erie. Mr. While states,
as his own conclusion, that they owe their origin to glacial move-
ment in the opposite direction. Mr. White's Report is occupied
mainly with stratigraphical details, but treats also of the disturb-
ances of the region, and of oil-wells and other points of general
interest. The oil or petroleum is attributed to generation in situ
from seaweeds, as urged by Lesquereux. He mentions the occur-
rence of a grit saturated with oil, in all parts of which were frag-

Geology and Natural History. 487

merits of trees, " like a fallen forest, or rather like a matted natu-
ral river-raft." A thin film of coal occurs on some specimens,
" but in most cases the wood looks as if it had been converted
into petroleum." In the underlying Venango Lower Sandstone
and the Chemung flagstones no trace of oil was found, and " the
horizontality, the absence of faults, slides, fissures or crushes of
any kind, make the ascent of petroleum in the shape of gas a
physical impossibility." The paper in this report by Dr. Spencer,
on the preglacial outlet of the Lake Erie Basin (into Lake Onta-
rio), has been noticed in this volume on p. 151. Professor Lesley
accepts of the general conclusion, but with reference to the sug-
gested origin of the lake-basins by the eroding action of a great
ancient St. Lawrence River, he makes the modifying statement
that the lake basins " although they may have been traversed by
a great river were not properly excavated by it," but by the gen-
eral abrading action of rills and streams from the rains descend-
ing the slopes into it, and probably by the removal of subjacent
limestone beds by undermining erosion. To make the drainage
system through the Great Lakes complete, so that the excavation
by river action could be carried through to the sea, it is necessary
to find an outlet for Lake Ontario cut down over 600 feet below
the channel of the St. Lawrence, for the lake is over 700 feet
deep ; and on this point no facts or satisfactory suggestions are
given.

2. First Annual Report of the U. S. Geological Survey ; by
Clarence King, Director. 79 pp. roy. 8vo. Washington, 1880.
— This volume (recently issued) contains, in reports from Mr.
King and the several members of the Geological Survey, a brief
review of the work done during the year ending June 30, 1 880.
The facts stated in these summaries are a promise of a very valu-
able series of reports on the several regions investigated; and the
assurance is given on page 69 of the speedy completion of twelve
volumes, as follows : Geology and Mining Industry of Leadville,
by S. F. Emmons; Geology of Eureka Mining District, Nevada,
by A. Hague ; The Copper rocks of Lake Superior and their
continuation through Minnesota, by R. D. Irving ; History of
the Comstock mines, by Eliot Lord ; the Comstock Lode, by G.
F. Becker ; Mechanical Appliances used in Mining and Milling
on the Comstock Lode, by W. R. Eckart ; Coal of the United
States, by R. Pumpelly ; Iron in the United States, by R.'
Pumpelly; the Precious Metals, by Clarence King; Uinkaret
Plateau, by C. E. Dutton ; Lake Bonneville^ by G. K. Gilbert ;
Dinocerata, by Professor O. C. Marsh.

3. The Kames of Maine; by G. H. Stone. 40 pp. 8vo.
From the Proceedings of the Boston Society of Natural History,
xx, 430-469. — The author describes k' kames" as observed by
him over a large part of the State of Maine, and on a map gives
their positions. They include " kame ridges, and also terrace-
like kame-plains." The kames sometimes follow valleys'; u freely
cross low transverse hills ;" are seldom " deflected by hills less

488 Scientific Intelligence.

than 100 feet high ;" in "no instance cross any hill where, coming
from the north, one would have to rise more than about 200 feet
in crossing it ; in fact the courses of the kames are curiously
arbitrary." His theory of their origin is essentially that of Mr.
Upham, cited on page 456.

4. Geology of Staten Island. — Mr. N. L. Britton has an arti-
cle, in the School of Mines Quarterly (New York) for May last,
on the geology of Staten Island — the large island lying to the
south-southwest of New York Island. The geological map accom-
panying it represents the serpentine area as running nearly
through the island, from New Brighton and Stapleton on the
north (or rather from Constable Point just north of the island) ;
gneiss as lying against this area on the east ; Triassic sandstone
and trap on the west ; Cretaceous beds on the eastern and south-
ern sides. A geological section is given ; but as the gneiss out-
crops only near Stapleton, and no strike or dip was taken, it is
almost wholly ideal, and, considering the facts on New York
Island, its details are very improbable. The asbestos exported
from the island — which is only fibrous serpentine and contains
therefore 12 to 14 per cent of water — comes from the area near
Tompkins ville Landing.

Along with the serpentine or " steatitic rocks, occur superficial
deposits of limonite, which have resulted from the decomposition
of the rocks, in place." It is stated that the amount hitherto
mined may be as great as 250,000 tons, while that now annually
mined is about 20,000 tons. The limonite of the serpentine area of
Rye, New York, (this Journal, II, xx, 32, 1880), is another ex-
ample of the ore made from the iron minerals of a serpentine
region ; but at Rye there is some ferriferous dolomite with the
serpentine, while the occurrence of disseminated limestone or dolo-
mite on Staten Island is not mentioned.

5. Apuan Alps. — A paper on the geology of the Apuan Alps,
by B. Lotti and D. Zaccagna, is contained in the R. Comitato
Geologico d' Italia, Bulletin Nos. 1 and 2, 1881. The rocks below
the lias, are stated to include, beginning below —

a. The central schists: mica schist, talc schist, gneissic and
argillaceous schist, with lenticular masses of calciferous schist
containing Orthoceras.

b. The zone of the Grezzoni : the rock so called being a rough-
looking impure limestone sparingly fossiliferous, subcrystalline or
ceroid and brecciform ; afforded De Stefani a fossil undoubtedly
Triassic, Turbo solitarius; about five hundred meters on an aver-
age in thickness.

c. The zone of the marbles: saccharoidal limestone and dolomite,
about 1,000 meters; some traces of Grinoids and Ghemnitzia.

d. The zone of the superior schists : consisting of an alternation
of schists, Cipolin marbles, calciferous, micaceous and arenaceous
schists, with beds affording Pentacrinus and small ammonites of
the genera Phylloceras and ^Egoceras ; 200 to 1,000 meters in
thickness.

The paper gives detailed descriptions with sections.

Geology and Natural History. 489

6. Jelly -like carbonaceous mineral resembling dopplerite, from
a peat bed hi Scranton, Pennsylvania. — An article by Mr. T.
Cooper in the number of the Engineering and Mining Journal for
Aug. 13, contains the following interesting facts: The remark-
able material was discovered in excavating for the new court-
house of Scranton. This building-site is in the heart of the town,
upon a square which formerly was a swamp, but some years ago
was filled with cinder from the iron-works. On excavating for
the court-house foundations, the cinder, which was five or six feet
deep, was first removed. After this, came a bed of excellent peat,
varying in depth from eight to twelve feet.. Below the peat, a
stratum of muck separated the peat from the hard-pan below. In
the muck were veins of the tough black jelly, resembling coal in
aspect, except its gelatinous character. When dried slowly it
solidifies into a hard, brittle substance, which would be considered
by an ordinary observer real anthracite coal. After hardening it
does not again soften in water, hot or cold. It bums at a red
heat, and leaves an ash resembling the red ash of some coals. It
flames on first ignition. The jelly is acted on by alkaline solu-
tions.

A letter to the editors, from Mr. H. Wright, secretary of the
Wyoming Historical and Geological Society, dated Wilkesbarre,
Aug. 27, 1831, states that an analysis made by the State Chemist
afforded

Water, at 212° P., 66-758

Volatile matter, 9 826

Fixed carbon, 4012

Ash,... 19-404

100-000

7. Emeralds from Alexander County, North Carolina. — Mr.
W. E. Hidden, whose important mineralogical labors in North
Carolina have been previously mentioned in this Journal (xx, 150 ;
xxi, 128, 159, 160; xxii, 21, 179), has recently announced the
discovery by him of emeralds sixteen miles northwest of States-
ville in Alexander County, North Carolina. The occurrence of
beryls of unusual beauty and crystallographic interest was made
known some years since by Mr. J. Adlai Stephenson. Mr. Hid-
den was led by this fact to make thorough and systematic search
in the hope of finding them in place, and he has succeeded in
finding not only the ordinary beryls but also true emeralds. The
prevailing rock of the region is a feldspathic gneiss with a strike
N.N.W., and nearly vertical dip. The surface soil often contains
crystals of quartz, rutile, tourmaline, spodumene, beryl, etc., and
in cross-fractures in the rock beneath, the minerals have been
found by Mr. Hidden in place ; of these minerals the emerald-
green spodumene (hiddenite), and the true emeralds have been
the special objects of search because of their value as gems. The
first pocket found has been worked to a depth of thirty-three feet
and has yielded largely of spodumene, but sparingly of the emer-
alds ; twelve similar cavities have been found within an area of

490 Scientific Intelligence.

forty feet square yielding emeralds, while still others have
afforded quartz, rutile, monazite, mica and other species. So far
as the explorations have been carried, the pockets have been in
a crumbling condition and the crystals have been found detached,
lying in the bottom of the cavities. As the work is earned down
deeper it is to be expected that the rock will increase in firmness.
The largest cavity yet discovered had a depth of sixteen feet, and
was three feet wide and seven in length. The surface walls were
thickly studded with large crystals of quartz, some of twenty-five
pounds in weight, and with them nine fine emeralds. Their form
was that of a twelve-sided prism (Zand z-2), with basal planes,
all well polished. The largest crystal had a length of eight and
one-half inches and an average diameter of one inch. The others
varied in length from two to six inches. Most of the crystals
found are vertically deeply striated or ribbed, and are transpar-
ent, though not free from flaws. In some of the crystals the
color near the surface is the deepest and the core is nearly color-
less. The North Carolina emeralds do not quite equal in color
those from Muso, New Granada, but are nevertheless very beau-
tiful and will bear comparison with those from other known
localities.

8. Brief notices of some recently described minerals. (Con-
tinued from page 155.) Ilesite. — A white friable mineral with a
bitter, astringent taste, readily soluble in cold water. An anal-
ysis afforded Dr. lies— S03 35'85, MnO 23-18, Fe0 455, ZnO 5*63
H20 30*1 8=99*39, corresponding approximately to Mn(Fe, Zn)
SG4-|-4aq. Occurs with pyrite and sphalerite forming a band two
to eight inches in width ; locality, Hall Valley, Park Co., Colo-
rado. Named after Dr. M. W. lies, of Leadville. — Mining
Index, Leadville, Nov. 5, 1881.

Semseyite. — Briefly mentioned by Kreuner as a mineral con-
taining lead, antimony and sulphur, occurring in gray crystals,
and resembling plagionite. Found with diaphorite, sphalerite
and pyrite at Felsobauya. — TJngarische Hevue, April, 1881.

Annerodite. — Occurs in crystals closely related to columbite
both in habit and angles. H.=6. G.=5*7. Luster metallic to
submetallic. Color, black to blackish-brown. Translucent in
thin splinters. Fracture sub-conchoidal. An analysis by C. W.
Blomstrand gave Cb205 48-13, Sn02 016, SiOa 2-51, ZrO, 1*97,
Th02 2-37, U203 16-28, Ce203 2-56, Y90, MO, PbO 2*40, FeO 3'38,
MnO 0-20, CaO 3-35, MgO 0*15, KaO 0-16, Na20 0-32, AlaOs 0*28,
H20 8-19=99.51. The formula deduced is R2Cb207-f2i aq,
which makes the mineral related p in composition to saraarskite.
Found in a pegmatite vein at Annerod, near Moss, Norway.
Described by W. C. Brogger. — GeoL For. i. Stockholm For-
handh, v, 354, 1881.

Zincalluminite. — Found in very small thin hexagonal crys-
tals ; optically, uniaxial negative. Color white, or slightly
tinted with blue. An analysis bv Damour gave SOs 12*94,
A1203 25-48, ZnO 34'69, CuO 1*85, H2° 2504=100. From the

Geology and Natural History, 491

zinc mines at Lauriuru, Greece, associated with smithsonite, ser-
pierite and several undetermined species. Described by Bertrand
and Damour. — Bull. Soc. Min. de France, iv, 135, 136, 1881.

Alaskaite. — Massive, small foliated. G.= 0*878. Luster,
metallic. Color, whitish lead-grav. Opaque. Analysis (after
deducting impurities), S 17-03/ Bf 50*97, 8b 0*62, Pb 11*79, Ag
8*74, Cu 3*40, Zn 0*79 = 100; another analysis gave 3 p. c. Ag, and
5*38 p. c. Cu. The formula deduced is (R,R)S-f BiaS8. Occurs
intimately mixed with quartz, barite, chalcopyrite and tetrahe-
drite at the Alaska mine, Poughkeepsie Gulch, Colorado.
Described by G. A. KOnig. — Arner. Phil. aSoc. Philad., 1881, 472.

9. Artificial formation of the Potash-feldspar, Orthoclase; by
C. Friedel and E. Sakasin (Bull. Soc. Min. de France, iv, 171).
— The process used by these chemists for the formation of ortho-
clase in crystals consisted in heating together in a tube of steel
having red copper within, for 15 to 20 hours to a temperature
between 400 and 500° C, a mixture one part of aluminum silicate
and another of a potassium silicate rich in alkali. A higher
temperature was disadvantageous, it producing a crystallization
of the silica either as quartz or as tridymite. The trials gave a
crystalline powder, which was made up of crystals of orthoclase
large enough to be studied crystallographically. Thoulet's method
gave for the specific gravity that of orthoclase. An analysis
afforded alumina 15*59, potash 14*38, leaving for the silica 70*03.
There is here an excess of silica of 0*30 per cent, which was due
to the presence of some free silica; the other ingredients have the
orthoclase proportions. The authors did not succeed when the
mixture was made to consist of silica, alumina and potash, in the
proportions they have in orthoclase.

10. English Plant-Names fro7n the Tenth to the Fifteenth Cen-
tury. By John Earlk, M.A., Rector of Swanswick, Professor
of Anglo-Saxon in University of Oxford. Oxford : Clarendon
Press, 1880. lOmo, pp. cxii and 122. — A notable little book, con-
sisting in the first place, — yet in the volume occupying the last
place, — of sundry Saxon vocabularies in which " the native plant-
names have been preserved in the most primitive form extant,
printed for the use of friends of Saxon studies" without any idea
of making a book. To this is prefixed an Introduction, on the
history of plant-names from Theophrastus down to the modern
system of nomenclature ; the signification of the old native plant-
names; their relation to the Roman ones; grammatical elements
of English plant-names; on the neglect of vernacular names, etc.
Of the matters linguistic we are not now to speak ; and probably
Professor Earle is only a superficial botanist. But his sketch of
the history of nomenclature, and of the development of mere
herb-lore or the rude knowledge of simples into botanical science
is as critically excellent as it is terse and fresh. Indeed, we know
of nothing half so good within so small a compass. Then we be-
gin to understand " the fascination of vernacular plant-names,"
which, as the author remarks, " has its foundation in two instincts,

492 Scientific Intelligence.

the love of nature and curiosity about language. Plant-names
are often of the highest antiquity and more or less common to
the whole stream of related nations. Could we penetrate to the
original suggestive idea that called forth the name, it would bring
valuable information about the first openings of the human mind
towards Nature ; and the merest dream of such a discovery in-
vests with a strange charm the words that could tell, if we could
understand, so much of the forgotten infancy of the human race."

Here is a good word for the amiable science, considered educa-
tionally. " Historically almost the first of sciences, Botany is
naturally and eductionally [educationally ?] first in order to the
enquiring mind. Its objects are near our homes, awakening to
our minds, and inviting to our touch. Botany is adapted to be
the universal preparatory science, the science to infuse the scien-
tific sense."

While giving a series of examples of the changing meanings of
a certain class of words, the author goes singularly astray in a
single instance : e. g. " In England farmer means an occupier, in
America it means a hired labourer." No,, indeed : it means a cul-
tivator of the land who is not a hired laborer: he is commonly
the owner of his farm in fee simple. A. G.

1 1. Familien Podostemacem. Studier af Dr. Eug. Wabming.
lte Afhandlung. — This is a paper in the Memoirs of the Royal
Academy of Sciences of Copenhagen, being the commencement
or first part of an extended treatise on the Podostemacece, mor-
phological, anatomical, and systematic. This singular family of
Phsenogamous plants, simulating Algce in vegetation, takes its
name from our Podostemon ceratophyllus, of Michaux's Flora,
the only North American representative, and the only one inhabit-
ing the North temperate zone. Having been well supplied by
Mr. Canby with a stock of plants in spirit, in all stages of growth,
Dr. Warming has taken this species for particular study, and his
anatomical and morphological investigation of its organs of vege-
tation is here presented. The body of the article is in the Danish
language. But an abstract and also the full explanation of the
plates are in French. The whole fills 34 quarto pages and is
illustrated by six plates, crowded with figures, drawn and litho-
graphed by the author himself. Three of the six plates and half
of the fourth are devoted to our Podostemon. a. g.

12. Recherches mr la physiologie et la morphologie des ferments
alcooliqiies. By Emtl Chr. Hansen. — The present paper, ex-
tracted from the proceedings of the physiological laboratory of
Carlsberg, Copenhagen, for 1881, treats of Saccharomyces apicu-
latus and its occurrence in nature. This ferment, according to
Hansen, is found during the warm season on juicy fruits, as goose-
berries, cherries, plums, etc., and is carried to the earth by winds
and rain and passes the winter buried in the soil. In fermenta-
tion it acts as a bottom yeast but possesses only a feeble action,
since, while the common yeast, Sacc. cerevisios produces six vol-
umes of alcohol, Sacc. apiculatus, produces only one. The beer

Geology and Natural History. 493

which it produces has a peculiar taste and odor. The species pro-
duces no invertine, nor can it cause an alcoholic fermentation in
saccharose solutions. The cells are very tenacious of life, can
be kept dried several months, and in this condition exposed to
marked variations of the thermometer without apparent injury.

w. G. F.

13. On an Organism which penetrates and excavates Siliceous
Sponge-spicules (Spongiophagus Carteri) ; by Professor P. Mar-
tin Duncan. — In a communication which I made to the Royal
Microscopical Society on June 8, 1881, the presence of green-col-
ored cells on siliceous sponge-spicula, in relation to minute pene
trations into their axial canals, was asserted. The occurrence of
a granular plasma of the same tint within enlargements of the axial
canals was noticed; and the penetration and erosion were stated
to be due to the organism. The cells which were observed within
hollows on the surface of a spicule, and also on perfect spicules in
positions where erosion from without inwards could readily occur,
were very small, — not more than T0Vtt mcn m length, and very
much less in height. Their dimensions, however, corresponded to
those of certain circular patches with hollowed-out bases, which
are the first stages of the penetration through the spicule down to
the axial canal. The penetration of the spicule down to the cen-
tral canal is followed by the growTth of the organism, which appears
to erode the silica and enlarges the canal in a most remarkable
manner.

After a while the spicule suffers solution of its continuity by the
thinning from within, and the thinnest flakes present a granulated
appearance.

Since writing that communication I have observed siliceous
sponge-spicules, obtained from great depths, which are affected by
an organism whose cells are much larger and whose penetrations
therefore are wider and much more visible. On the head of a large
spinulate spicule I found many circular pits, each containing an
organic mass without definite cell-wall, and yet granular and green
in color by transmitted light. These pits are shallow and are
sxjVa inch in diameter. Similar pits and of the same dimensions
are seen on other spicules ; but they are deep and resemble cylin-
drical tubes with hollowed-out bottoms. Some reach the axial
canal, which has become enlarged. The penetrations contain
granular organic substance ; and so do the enlarged axial canals.
The walls of the enlarged axial canals are frequently very irregu-
larly eroded and look " worm-eaten ; " the hollow's are, moreover,
green with the very visible granular matter.

Thus there are two dimensions of the penetrations. The first
kind of cell found on the spicules resembles somewhat the simple
zoospores of Achlya penetrans Duncan (Proc. Royal Soc, vol xxv,
pi. vi) ; the second is larger ; and in both there is a decided green
tint. No ramifications of the penetrating cylindrical tube occur ;
and it pierces perpendicularly to the surface of the spicule, or, it
may be, slightly aslant.

494 Scientific Intelligence.

The presence of pits on the surface of sponge-spicules was noticed
by Kolliker as a peculiar degeneration of the structure. Dr.
Carter described and figured pits in the outer part of a spicule,
and distinctly referred them to the action of a vegetable cell, in
the Ann. & Mag. Nat. Hist. ser. 4, vol. xii, p. 457, pi. xvi, figs. 8, 9.
None of the pits seen by ray friend reaches the axial canal ; but
some of them terminate in globular excavations.

It is evident that the assimilation of the organic substance in
the sponge-spicule by the vegetable organism produces the de-
struction of the siliceous structure ; and probably the colloid silica
unites with the protoplasm of the destroyer and forms an organic
compound with it.

Large cells and small nucleus-like cells operate, producing
penetrations of corresponding diameters through the spicule down
to the axial canal. The vegetable growth occurs there ; and the
amount of erosion does not appear to be in relation with the size
of the primary penetration.

The organism is not an Achlya ; and all that can be said is
that it consists of cell-like bodies without very definite cell-walls,
but evidently with a very delicately limiting texture surrounding
a granular greenish plasma, and that there is much free and non-
cellular plasma with bodies like small nuclei, the whole having a
faint green tint. I have named this very lowly organic substance
(which is probably a plant) Spongiophagus Carteri. — Ann. <k
Mag. Nat. Hist., Aug., 1881, p. 120.

14. Bulletin of the Museum of Comparative Zoology at Har-
vard College. Vol. VI, Part ii, No. 12. E. L. Mark on the
Maturation, Fecundation and Segmentation of Limax campestris
Binney. pp. 173-625, 8vo, with 5 double plates. — A pro-
found microscopic research throwing new light on the metamor-
phosis of the nucleus and other points in the earliest stages of
egg-development, reviewing at length, with criticisms, previous
researches on the subject, and giving an extended bibliography.

15. The Palwocrinoidea. — Part II of Wachsmuth and Spring-
er's revision of the Paheocrinoidea is contained in the Proceedings
of the Academy of Natural Sciences of Philadelphia for 1881,
commencing with page 177. It is devoted to the Family Sphae-
roidocrinidse, under which are included the Sub-families Platycri-
nid*e, Rhodocrinidie and Actinocrinidae. It is a long and very
valuable paper.

(Cosmos les Mondes : Revue hebdomadaire des Sciences et de
V Industrie, fondee et dirigee pars M. I' Abbe F. Moigno, Paris.
— The valuable weekly review, les Mondes, commenced by M.
l'Abbe Moigno in 1852, appears now in new form, enlarged in
size and improved in appearance. The Abbe still retains the
direction of the review, but he has the assistance of a group of
collaborators, under whose combined efforts it promises to have
an increased sphere of usefulness in the future.

INDEX TO VOLUME XXII.*

Abbott, C. C, Primitive Industry, 401.

Acid, nitrous, in evaporation of water,
145.
pentathionic, 73.

Agassi?, A., Hseckel's Medusae, 160.
Echini of the " Blake," 413.

Anthracite mining, 152.

Arctic observations, 164.

Arsenic, spectrum of, Huntington, 214.

Arsenobenzene, 71.

Association, American, Cincinnati meet-
ing, 86, 240.

British, Lubbock's address, 268,343.

Aurora of Sept. 12-13, 1881, Schceberle,
341.

Bailey, W. W., Botanical Collector's
Handbook, 326.

Barker, G. F., chemical abstracts, 71,
145, 217.

international congress of electri-
cians, 395.

Barometric observations, reduction of,
Loomis, 1.

Bases, new organic, 219.

Bean. T. H., fishes of the New England
coast, 295.

Bell, A. G., a modification of Wheat-
stone's microphone, 87.

Bells, ancient Japanese bronze, 326.

Berthelot, spontaneous oxidation of mer-
cury, 217.

Birds, Jurassic, see Geology.

Blake, W. P., vanadinite in Arizona, 235.
ulexite in California, 323.
vanadates of lead at Castle Dome
mines, Arizona, 410.

Boron hydride, 147.

Boss, L., comet b, 1881, 140.
tail of comet 6, 1881, 303.

Boston Society of Natural History, 85.

Botany —

Algae, New England, 158.
Alismaceae, 236.
Corallines of Naples, 325.

Botany —

Cucurbitaceae, 237.

Ferments, alcoholic, 492.

Fungi, morphology and physiology of,
324.

Spongiophagus Carteri, 493.

See further under Oeology.
Bouve, T. T., Boston Soc. Nat. Hist., 85.
Braithwaite, R., British Moss Flora, 239.
Broadhead, G. C, Carboniferous rocks

of Kansas, 55.
Brooks, W. K., Development of the

Squid, 414.

Cadmium, atomic weight of, 148.
Campbell J. L., dufrenite from Rock-
bridge Co., Va., 65.
Carbon disulphide, purification of, 147.
Carpenter, P. II., Report on the Conia-

tulae, 413.
Chemical Society, American, 165.
Cipher-code for astronomical telegrams,

245.
Climate of western United States, 247.

secular changes of, JfcGee, 437.
Coal-dust, danger from, in mining, Hovey,

81.
Coan, T., volcanic eruption in Hawaii,

227, 228, 322.
Cold from reaction of solids, 206,
Comet b, 1881, observations of. Boss,
140, 303, Burton, 1G3, Christie, 164,
Harkness, 137. Flolden, 260.

photographs of spectrum of, 134,
163.

polarization of light of, Wright,
142.

spectroscopic observations of,
135, 137, 164.

tail of, Boss, 303.
c, 1881, polariscopic observations
of, Wright, 372.
Conistock, C. #.. variation of a zinc bar

at the same temperature, 26.
Conductivity of metals, 316.
Cooke, J. P., Principles of Chemical
Philosophy, 398.

* This Index contains the general heads Botany, Geology, Mineralogy, Obituary,
Zoology, and under each the titles of Articles referring thereto are mentioned.

496

INDEX.

Cooper. T.. jelly-like mineral resembling

dopplerite, 489.
Cope, E. D., arrangement of the Peris-

sodactyles. 163.

Eocene saurian and mammals, New

Mexico, 408.

Miocene Rodents and Canidae of

the Loup Fork. 408.
Cwmos les Mondes, 494.
Cyclones, tornadoes and waterspouts,

Ferrel 33.

Dali. W. H.. Report on the M oil u sea.
413.

Dana, E. S., emerald-green spodumene.
179.

Dana, J. D., appendages of trilobites. 79.
limestone of Westchester Co.. 1 03,
313. 327.
iron ore of Rhode Island, 152.
doleryte of eastern X. America, 230.
iron ores of Marquette, 320, 402.
il Karnes *T of the Connecticut River
Valley, 451.

Darwin, G. Bn stresses caused by con-
tinents and mountains. 317.

Daubree, substances from "forts vitri-
fies," 150.

Dawson, G. M., geology of British Co-
lumbia, 75.

Dawson. J. W., structure of Uphantaenia.
132.

De Bary, A., Morphologie und Physiol-
ogic der Pilze. 324.

De Candolle. Monographia? Phaenoga ma-
rum, 235.

Dextrose, transformation of into dextrin,
72.

Dodge. W. W., Lower Silurian fossils in
Maine. 434.

Draper, H.. photographs of spectrum of
comet of June, 1881, 134.

Dust, so-called cosmical, 86.

Dutton. C. E„ arid climate of Western
United States 247.

Dynamo-electric machines, 484.

Earle, J.. English Plant Names, 491.
Earth, stresses in interior of. 317.
Earthquakes, Japanese. Rockwood. 468.
Eaton. D. C, Farlow's New England

Algae. 158.
Ebonite, transparency of, 148.
Elasticity and motion. 396.
Electric absorption of crystals, 147.

machines. 484.
Electrical exhibition, Paris, 395.

Electricity, conservation ol 74* 148.

storing of, 75.

transmission of power by. 397.

see also Yoliaic arc.
Electro-dynamic balance, 398.
Elevation, see Height.
Entomological Commission. Bulletin. 415.
Ether, motion ol MicheJLson, 120.
Etheridge. R., Presidential Address, 410.

Farlow, IF. G., botanical notices, 324, 492.
Marine Alga? of New England, not,
158.

Faxon, W., articles on Crustacea, 414.

Ferrel, W.. cyclones, tornadoes and wa-
terspouts, 33.

Fewkes. J. W., articles on marine inver-
tebrates. 413, 414.

Fluorine, free, in fluor spar, 71.

Ford, S. W., embryonic forms of trilo-
bites. 250.

Forts vitrifies, materials from, 150.

Fossil, see Geology.

Fraunhofer lines, see Spectrwrn.

Fusion, mode$ of, 220.

Gabb, W. M.. Caribbean Miocene Fos-
sils. 77.
Garman. S.. New Reptiles and Fishes,

162.
Geological Reports and Subveys —

Alabama. 80.

Indiana, 78.

Xew Jersey. 77.

Pennsylvania, 78, 152, 485.

Rocky Mountains (Powell), 399.

Territories (Hayden), 408, 409.

United States. King's, 487.
Geology —

Alps. Apuan, 488.

Alteration of superficial deposits, 80.

Alveolites, Thomson, 235.

Anthracite mining, 152.

Birds. Jurassic, and their allies, Marsh,
337.

Black Hills, 399.

Brazos coal-field, Texas, 152.

British Columbia. 75.

Carboniferous of Kansas, Broadhead.
55.

Caribbean Miocene fossils, 77.

Climate, secular changes in, 437.

.Cortlandt series, Dana, 103.

Cosmical dust, so-called, 86.

Cyathophycus, Waleott, 394.

Deer horns, impregnated with tin ore,
81.

INDEX.

497

Geology —

Devonian plants, Dawwm, 233.
Dictyophyton. Whitfield, 53, 132.
Diluvium, gray and red, 80.
Dinoceras, restoration of, Marsh, 3 1 .
Doleryte of N. J. and Conn.. 230.
Dust, cosmical, 86.
Felsites, etc., near Boston, 80.
Glacial action in Pennsylvania, 486.
dnft, Mt. Ktaadn. 229.
in New Jersey, 77, 401.

ice-sheet, thickness of, McGee. 264.
subsidence produced by, McGee,

368.
Glaciers, illustrations of, 78.

Glacier scratches, Goshen, Conn., 322.
Grezzoni of Italy, 488.

Gulf of Mexico, Tertiary of, Hilgard.

58.
Ice sheet, subsidence produced by,

McGee, 368.
Irish Elk, deposits containing, 408.
Iron ores of Marquette district, 320,

402, 403.
of Rhode Island, 152.
Jurassic birds and their allies, Marsh,

337.
Kansas, Carboniferous in, Broadhead.

55.
Karnes of the Connecticut River Val-
ley, Dana, 451.

of Maine, Stone, 487.
Laccoliths, Ireland, 152.
Lake Erie, preglacial outlet of, 151,

486.
Lake-basin, Tertiary, of Florissant,

409.
Laramie group, New Mexico, Steven-
son, 370.
Limestone of Westchester Co., Dana,

103, 313, 327.
Maine, Lower Silurian fossils in, 434.

Karnes of, Stone, 487.
Mammals, Eocene of New Mexico,

408.
Minas Geraes, Brazil, 221.
Mt. Ktaadn, glacial drift on, 229.
New Jersey, geology of, Cook, 77.
Norway, terraces and coast lines, 149.
Noryte, analysis of, 104.
Oil regions of Penn., 78.
Plants, Devonian, Dawson, 233.
Lignitic, Manitoba, 233.
Silurian of Wales, 153.
Pterygotus, Pohlman, 234.
Rodents, Miocene, 408.
Saurian, Eocene, 408.
Staten Island geology, 488.
Stresses caused by continents, 317.
Taconic near Lake Champlain, 321.
Terraces and ancient coast lines, 149.

32a

| Geology —

Tertiary Lake - basin of Florissant,

Colorado, 409.
Trap of Eastern N. America, 230.
Trenton gravel, 401.
Trilobites, Wcdcott, 79.

embryonic, Ford, 250.
Uphantaeuia, Dawson, 132.
Valleys, old, tilled with drift, 486.
, Vertebrate, Permian of Texas, Cope,

153.
I Westchester Co. limestone. Dana, 103,

313, 327.
i Glaciers, etc., see Geology.
Gray. A., botanical notices. 235, 491.

Haeckel, E.. Medusen, noticed. 160.
Hall, A., Double Star Observations, 84.
Hansen, E. C, on alcoholic ferments,

492.
Harger, O., New England Isopoda, 411.
Harkness, W., comet b, 1881, 137.

solar parallax, 375.
Hawaii, volcanic eruption in, 226, 322.
Hawes, G. W., doleryte of Eastern N.

America, 230.
Height of signal service stations, 18.
Ifesperidin, 218.

Hidden, W. E., mineral localities in
North Carolina, 21.
North Carolina emeralds, 489.
Hilgard, E. W., Tertiary of the Gulf of
Mexico, 58.
soil analyses, 183.
Cotton Production of Louisiana, 246.
Hitchcock, D. H, volcanic eruption in

Hawaii. 228.
Holden, E. S., light of telescopes used
as night-glasses, 129.
comet b, 1881, 260.
Hovey, II. C, danger from coal-dust in

mining, 18.
Huntington^ 0. W., atomic weight of
cadmium, 148.

spectrum of arsenic, 214.

Tee, heating of, 148, 220.

Jenney, W. P., Geology of the Black
Hills, 399.

Jolly's hypothesis as to cause of varia-
tions of oxygen in the air, 429.

498

INDEX.

Ketines, 219.

King, C.}j Report of U. S. Geological
Survey,J487.

Lasatdx, so-called cosmical dust, 8G.
Lavallee, A., Arboretum Segrezianum,

238.
Light, velocity of, 316.

see also Polarization.
Liquefaction from reaction of solids,

Walton, 206.
Liversidge, A., torbanite of New South

Wales, 32.
Loomis, E.u meteorology, 1.
Lubbock, presidential address, 268, 343.

Magnetic observations in Davis Strait,

Sherman, 49.
Magnetization of iron and steel, 398.
Mallett, J. W., crystalline form of sipylite.

52.
Mark, E. L., on development of Limax

campestris, 494.
Mars, ephemeris of satellites of, 485.
Marsh, 0. C, restoration of Dinoceras,

31.
Jurassic birds and their allies, 337.
McGee,W. J., thickness of ice-sheet at

any latitude, 264.
local subsidence produced by an

ice-sheet, 368.

secular climatal changes, 437.
McMaster, J. B., Bridger Beds, 235.
Melting, modes of, 220.
Mercury, distillation of in vacuo, Wright,

479.

oxidation of, 217.
Metallic vapors, reversal of lines of, 220.
Meteoric iron, new, Shepard, 119.

dust,- 86.
Meteorology, contributions to, Loomis, 1.
Michelson, A. A., relative motion of the

earth and luminiferous ether, 120.
Microphone, Bell, 87.
Miller, S. A., North American Mesozoic

and Oenozoic Geology, 234.
Milne-Edwards, A., Crustacea of the

"Blake," 413.
Minerals, optical characters and crystal-
line system of, 153.
separation of, 80.
Minerals —

iEschynite, 23.

Alaskaite, 491.

Annerodite, 490.

Arctolite, 156.

Beryls, North Carolina, 24, 489.

Minerals —

Brackebuschite, 157.

Chalcomenite, 155.

Chrysolite, 152.

Crocoite, 198, 203.

Cryoconite, 86.

Dawsonite, 157.

Descloizite, 201.

Dopplerite, mineral resembling, 489.

Dufrenite, 65.

Dumortierite, 157.

Emeralds, 489.

Fredricite, 156.

Frigidite, 156.

Hiddenite, 179, 489.

Ilesite, 490.

Itabirite, 222.

Lautite, 155.

Limonite, 488.

Microlite, 82.

Mimetite, 202.

Monazite, 21, 22.

Orthoclase, artificial, 491.

Platinum, 25.

Quartz crystals, 23.

Samarskite, 23.

Schneebergite, 156.

Semseyite, 490.

Serpierite, 156.

Sipylite, 52.

Spodumene, emerald-green, 179, 489.

Thenardite, 204.

Torbanite of New South Wales, 32.

Tritochorite, 155.

Turquois of New Mexico, 67.

Tyreeite, 156.

Ulexite, 323.

Uraninite, 22.

Vanadinite, 198, 235.

Vauquelinite, 198, 203.

Volborthite, 201.

Wollongongite, 32.

Wulfenite, 198, 203.

Zincalluminite, 490.
Morley, E. W., cause of variations in the

amount of oxygen in the air, 417.
on Jolly's Hypothesis, 429.
Morse, E. S., changes in Mva and Luna-

tia, 323, 415.
worked shells in New England

shell-heaps, 323.
ancient Japanese bronze bells, 326.
Mountains, stresses caused by, 317.

Newcomb, S., Transit of Venus, 84.
Newton, H., geology of Black Hills, 399.
Newton, H. A., astronomical notices, 84.
416.
obituary of Benjamin Peirce, 167.

INDEX.

499

Niagara Falls as a source of energy, 397.

Nichols, electrical resistance of incandes-
cent platinum, 363.

Nicholson, H. A., Structure and Affini-
ties of Monticulipora, 322.

North Carolina mineral localities, Hid-
den, 21, 489.

Obituary —

Delesse, Achille, 166.

Deville, B. H. St. C, 166.

Linnarsson, G., 416.

Peirce, Benjamin, 167.
Observatory, U. S. Naval, observations

at, in 1876, 416.
Ohm, value of the, 484.
Osborn, H. F., Loxolophodon and Uinta-

therium, 235.
Oxidation, spontaneous of metals, 217.
Oxygen, variations in amount of in the

air, Morley. 417, 429.
Ozone as a cause of the luminosity of

phosphorus, 145.

Packard, A. S., The Hessian Fly, 415.

Pettersen, K., terraces and ancient coast-
lines, 149.

Photographs of spectrum of comet, 134,
163.

Planets, figures of, 82.

Plants, see Botany and Geology.

Platinum, electrical resistance of. Nich-
ols, 363.

Poggendorff, J. 0., Dictionary of the
Exact Sciences, 245.

Pohlman, J., Pterygotus, 234.

Polarization of heat rays, change of
plane of by electro-magnetism, 397.
of light of comets, 137, 142, 372.
rotation of plane of by earth's
magnetism, 484.

Polar stations: international, 164.

Pritchett, H. S., ephemeris of satellites
of Mars, 485.

Prudden, T. M., Manual of Histology,
414.

Radiophonic researches, Bell, 87.
Reyer, B., Zinn, noticed, 157.
Hockwood, C. G., notes on earthquakes,

289.
Japanese seismology, 468.
Hood, 0. N., obtaining and measuring

very high vacua, 90.

Satellites of Mars, ephemeris of, 485.
Schaeberle, J. M„ aurora of Sept. 12-13,
1881, 341.

Scudder, S. II., Butterflies, noticed, 239-
Tertiary lake-basin of Florissant,
409.

Seismology, Japanese, Hockwood, 468.

Selenium, microphonic action of, 317.

Shaler, N. S., Illustrations of the Earth's
Surface, noticed, 78.

Shells, worked, in New England shell-
heaps, 323.

Shepard, C. IT., a new meteoric iron,
119.

Sherman, 0. T.. magnetic observations
in Davis Strait, 49.

Silliman, B.. turquois of New Mexico,
67.

mineralogical notes, 198.

Smith, J. L., collection of minerals, 166.

Smith, S. J., Prudden's Histology, 414.
articles on Crustacea, 4 1 2.

Smithsonian Inst. Report, 165.

Soil analyses, Hilgard, 183.

Solar, see Sun.

Solids, cold from reactions of, 206.

Solms-Laubach, Corallina, 325.

Sound, intensity of, 219.

Sound-waves in organ pipes, 316.

Specific gravity, separation of minerals
by, 80.

Spectroscopes, efficiency of, 397.

Spectrum of arsenic, 214.
see also Comet.

Spectrum-lines of metallic vapors, re-
versal of, 220.

photometry of, 219.

Spencer, J. W., preglacial outlet of Lake
Brie, 151, 486.

Sprengel pump, Hood, 90.

Stars, photography of, 75.

Stereoscope, Stevens. 358, 443.

Stevens, W. LeConte, the stereoscope,
358, 443.

Sterenson, J. J., Laramie group of South-
ern Now Mexico, 370.

Stockwell, J. N., Theory of the Moon's
Motion. 415.

Stone, G. H., the kames of Maine, 487.

Stresses caused by continents and moun-
tains, 317.

Sun, parallax of, Harkness, 375.

Telescopes used as night-glasses, Holden,

129.
Temperature variations of a zinc bar,

Comstock, 26.
Thorn sou, J., Alveolites, Amplexus and

Zaphrentis, Scotland, 235.
Tornadoes and waterspouts, Ferret, 33.
Trowbridge, J., physical notices, 74, 147,

219, 316, 396, 484.

500

INDEi.

Tucker, J. H., Manual of Sugar Analysis,
398.

Vacua, obtaining and measuring of high,

Rood, 90.
Venill, A. E., fauna of outer banks, 292.
recent papers on marine inverte-

brata of Atlantic coast. 411.

Cephalopoda from Steamer Blake,

162.
Vision by optic divergence, Stevens, 358,

443.
Volcanic eruption in Hawaii, 226, 322.
Voltaic arc, inverse electromotive force

of, 74.

Wachsmuth and Springer, Palaeocri-
noidea, 494.

Wadsworth, M. E., iron ores of Mar-
quette, 320, 402, 403.

WoJcott, C. D., on Cyathophycus, 394.
The Trilobite, 79.

Walton, E. M., liquefaction and cold
from reaction of solids, 206.

Warming, E., Podostemaceas, 492.

Waterspouts, tornadoes and, FerreU 33.

Weather warnings, 75.

Webster, H. E., Annelida Chaetopoda of
of New Jersey, 414.

Whitfield, E. P., nature of Dictyophyton,
53, 132.

Williams, H. S., Life History of Spirifer

he vis, 153.
Wilson, E. B., Reports on Pycnogonida,

412, 413.
Wilson, K. L., Photographies, not., 73.
Wright, A. W., polarization of light

from comet b, 1881, 142.
polariscopic observations of comet

c, 1881,372.
distillation of mercury in vacuo, 479.

Yowng, 0. A., spectroscopic observations
of comet b, 1881, 136.

Zinc bar, variations of, Comstock, 26.
Zoology -

Fauna of outer banks, 292.
Pishes of New England coast, 295.
Invertebrates, marine, recent papers

on, 411.
Lunatia, changes in, Morse, 323, 415.
Medusas, 160.
Mya arenaria in California, 82.

changes in, Morse, 323.
Rhizopods as food of fishes, 82.
Sponge - spicules, organism penetrat-
ing, 493.
See further under Geology.

X)RD UNIVERSITY I
Stanford, California

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