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VOLUME L
191 1

PHILADELPHIA
THE AMERICAN PHILOSOPHICAL SOCIETY

191 1

Press o<=
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CONTENTS

The Formation of Coal Beds. By John J. Stevenson i, 519

The Transpiration of Air through a Partition of Water. By

C. Barus 117

EIHptic Interference with Reflecting Grating. By C. Barus. . . 125
On the TotaHty of the Substitutions on 11 Letters which are
Commutative with every Substitution of a Given Group on

the same Letters. By G. A. ]\Iiller 139

Notes on Cannon — Fourteenth and Fifteenth Centuries. By

Charles E. Dana 147

Aloreau de Saint Alery and his French Friends in the American

Philosophical Society. By Joseph G. Rosengarten 168

The New History. By James Harvey Robinson 179

The Atomic Weight of \*anadium determined from the Labor-
atory Work of Eighty Years. By Dr. Gustavus X). Hin-

richs 191

The Origin and Significance of the Primitive Nervous System.

By G. H. Parker 217

The Stimulation of Adrenal Secretion by Emotional Excite-
ment. By W. B. Cannon, U.D 226

The Cyclic Changes in the Mammalian Ovary. By Leo Loeb. . 228

The Solar Constant of Radiation. By C. G. Abbot 235

Self-luminous Night Haze. By E. E. Barnard 246

Spectroscopic Proof of the Repulsion by the Sun of Gaseous
Alolecules in the Tail of Halley's Comet. By Percival

Lowell 254

The New Cosmogony. By T. J. J. See 261

The Extension of the Solar System Beyond Neptune, and the
connection existing between Planets and Comets. By T. J.

J. See 266

The Secular Effects of the increase of the Sun's Mass upon the
Alean Motions, Major Axes and Eccentricities of the Orbits

of the Planets. By T. J. J. See 269

On the Solution of Linear Dift'erential Equations of Successive

Approximations. By Preston A. Lambert 274

iii

iv CONTENTS.

Problems in Petrology. By Joseph P. Iddings 286

A Study of the Tertiary Floras of the Atlantic and Gulf Coastal

Plain. By Edward W. Berry 301

An Optical Phenomenon. By Francis E. Nipher 316

Symposium

I. The Alodern Theory of Electricity and Matter. By

Daniel F. Comstock 321

II. Radioactivity. By Bertram B. Boltwood 333

III. The Dynamical Effects of aggregates of Electrons.

By Owen W. Richardson 347

IV. The Constitution of the Atom. By Harold A. Wilson,

F.R.S 366

The High X^oltage Corona in Air. By J. B. Whitehead 374

Disruptive Discharges of Electricity Through Flames. By

Francis E. Nipher 397

The Desert Group Nolineje. By William Trelease 405

Isostasy and Mountain Ranges. By Harry Fielding Reid. . . . 444
A Fossil Specimen of the Alligator Snapper (Macrochelys tem-

minckii) from Texas. By Oliver P. Hay 452

An Hydrometric Investigation of the Influence of Sea Water

on the distribution of Salt Marsh and Estuarine Plants. By

John W. Harshberger, Ph.D 457

The Cost of Living in the Twelfth Century. By Dana C. Munro 497
An Ancient Protest against the Curse of Eve. By Paul Haupt 505
Obituary Notices of Members Deceased

Henry Charles Lea iii

Jacobus Henricus Van't Hoff iii

George Frederick Barker, M.D., Sc.D., LL.D xiii

Minutes iii-xiv

Corrigendum xv

Index xvii

PROCEEDINGS

OF THE

American Philosophical Society

HELD AT PHILADELPHIA

FOR PROMOTING USEFUL KNOWLEDGE

Vol. L. January-April, 191 i. No. 198.

CONTENTS.

The Formation of Coal Beds, I. By John J. Stevenson i

The Transpiration of Air through a Partition of Water. By C. Barus 117

Elliptic Interference with Reflecting Grating. By C. Barus 125

On the Totality of the Substitutions on n Letters Which are Commutative with

every Substitution of a Given Group on the Same Letters. By G. A.

Miller 139

Obituary Notices of Members Deceased

Henry Charles Lea iii

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Vol. L January-April, 1911 No. 198

THE FORAL\TIOX OF COAL BEDS.

I.

An Historical Summary of Opinion from 1700 to the present

TIME.

Bv JOHN J. STEVENSON.
(Read April Ji, 191 1.)
Preliminary Note.

Preparation of a monograph on any subject which interests stu-
dents in many lands requires thorough study of the hterature as a
preparatory step. But that Hterature has grown to such proportions
tl It one often becomes discouraged and is burdened with the fear
tha' hfe will be spent in making ready and that the grave \\'\\\ have
been reached before the monograph has been begun. Yet such pre-
liminary research is not without compensation, for one discovers that
his own period is not so far in advance of days gone by as he had
supposed ; that his contemporaries, with all their advantages, have
done little more, in many instances, than to place newer and finer
clothing on the generalizations of earlier students who had vvorked
within narrower areas.

This is not to say that niodern workers have appropriated know-
ingly the results obtained by iheir predecessors. The writer has dis-
covered very few instances of ^hat sort. For the most part, generali-
zations have been made, dc noyo, in ignorance of those previously
formulated. The literature has become vast; the papers are scat-

PROC. AMER. PHIL. SOC. L. I98A, PRINl.'.D APRIL 24, I9II.

1

2 STEVENSON— FORMATION OF COAL BEDS. [April 21.

tered in publications of many societies in six or more languages ;
many were merely separate pamphlets, now almost inaccessible.
Great scientific libraries are few and they are beyond reach of the
ordinary field-worker; while college professors and men connected
with official surveys rarely have leisure needed for thorough re-
search. The necessity for prompt publication, that fellow workers
may have the advantage of one's results, makes long preliminary
study almost impossible, in some cases almost unjustifiable.

The writer, looking forward to preparation of a monograph on
formation of coal beds, has examined many hundreds of publications
varying from mere notices to ponderous quartos and this preliminary
work is still far from complete. During the examination, he has dis-
covered not only that there is little new under the sun but also that
much, which is good and important, soon passes from men's minds.
He has discovered also that owing to quotation at second-hand, with-
out verification, some conclusions ofifered by the earlier students have
been misunderstood or even misinterpreted, so as to discredit the
authors. He has become convinced that a systematic presentation
of conclusions reached by his predecessors would not be useless or
unacceptable; it would exhibit the gradual development of opinion
and it would lead to proper appreciation of investigations made and
conditions, which, in this day, would be regarded as unfavorable ; it
would aid the students hereafter by indicating the road along which
to pursue his preliminary examination. Such presentation is offered
in the succeeding pages.

In preparing this historical summary, the writer, recognizing the
necessary limits of space, is compelled to note only such publica-
tions as deal especially with the topic under consideration ; and of
those, only such as are the outcome of direct study. The reader
may be disappointed by the omission of some authors and by the
admission of others ; but this is unavoidable. Many important re-
flections have been made by writers incidentally ; those will be noted
in the final discussion. No reference to opinions respecting the
origin of coal is given, except in cases where that question is basis
of the author's conclusion res]X"cting the mode of accumulation.

The plan of the summary may be open to criticism. The

2

191 1.] STEVEXSOX— FORMATIOX OF COAL BEDS. 3

original plan was to arrange the synopses topically, but this separated
the contrasting opinions of contemporaries ; the chronological
arrangement is open to the objection, that it breaks up the line of
argument for or against an hypothesis. Yet the latter seems pre-
ferable as more in accord with the purpose of the summary. It
has been followed, except where it would fail to show an author's
final conclusions or where it seemed necessary to bring together
widely separated observations upon a special phase.

The Hypotheses.

There has been little diversity of opinion respecting the origin of
coal. Geologists and chemists, with rare exceptions, have recognized
that the several types consist mainly of vegetable matter which has
undergone chemical change. But no such consensus of opinion
exists respecting the mode of accumulation in beds ; geologists, for
about one hundred and thirty years, have been divided into two
opposing camps with here and there an individual warrior carrying
on an independent strife.

The older hypothesis was suggested more than two centuries ago,
prior to the era of investigation, and it remained unchallenged until
the latter part of the eighteenth century, but it fell into disfavor
early in the nineteenth century. Thereafter, it had few, but earnest
defenders until within the last thirty years, during which it has been
urged with great energy. This, the doctrine of allochthonous origin,
conceives that coal beds are composed of transported vegetable
matter deposited in the sea or in lake basins. The conception has
assumed many forms but the essential feature of transport is com-
mon to all.

The other hypothesis, formulated in 1778 as the result of broad
field observations gained general acceptance about one hundred
years ago ; since that time, it has been held in one form or another
by a majority of geologists who have studied the coal measures. It
is known as the doctrine of growth /;/ situ, but von Gumbel's term,
autochthonous, has come into general use. According to this
hypothesis, the plants which yielded the vegetable matter grew where
the coal is found, analogous conditions being found in great peat
accumulations, especially those of the cypress swamps of North

8

4 STEVENSON— FORMATION OF COAL BEDS. [April 21.

America. That additional material may be brought in from time
to time bv transport is conceded, but the quantity thus added is com-
paratively unimportant. Equally the formation of a coal deposit by
transport is conceded but not the formation of a typical coal bed.

The Synopses of Opinions and Results.

Woodward^ explained all stratified rocks as deposits from the
original menstruum. During the time of the deluge, the solid
materials were wholly " dissolved." They were mingled with un-
consolidated materials such as sand, earth as well as animal and
vegetable matters and all were assumed and sustained by the water
in a confused mass. In time, these materials subsided " as near as
possibly could be expected in so great confusion, according to the
laws of gravity," those having the least gravity settling last of all
and covering the rest. '' The matter, subsiding thus, formed the
strata of stone, of marble, of cole, of earth and the rest." That
Woodward thought coal to be of vegetable origin cannot be deter-
mined with certainty : his remark that vegetable materials, being
of less specific gravit\- than mineral matter, would be precipitated
last of all and so form the outermost " stratum of the globe "
seems to suggest a contrary belief.

Whiston- took issue with Woodward and asserted that the
hypothesis presented by that author " includes things so strange,
wonderful and surprizing that nothing but the utmost Necessity,
and the perfect unaccountableness of the Phenomena without it,
ought to be esteemed sufificient to justify the Belief and Introduction
of it." At the time of the Xoachic deluge the earth passed through
the " Chaotick Atmosphere of a Comet " and thus acquired a great
amount of new material which mingled with the loose materials of
the globe. These subsided according to the laws of specific gravity,
giving the strata of stone, earth and coal ; in all about 105 feet thick.
Whether the coal is terrestrial or cometary in origin cannot be
ascertained by study of this work. The author's conclusions are

^ J. Woodward, " An Essay Toward a Natural History of the Earth and
Terrestrial Bodies," 2d cd.. London, 1702, pp. /2, 74, 77.

^W. Whiston, "A Now Theory of the Earth," 4th cd., London, 1725, pp.
^77, 278, .365, 419, 423, 425.

4

191 1.] STEVEXSOX— FORMATION OF COAL BEDS. 5

fortified by a wealth of mathematical proof which, apparently,
leaves little to be desired.

Scheuchzer'^ described a deposit of black slate in the canton
of Glarus, occurring in layers, one third of an inch thick, each
consisting of a hard upper and a soft lower lamina. The phenomena
observed in the quarry led him to assert "This is now certain that
all rock beds were formed by precipitation, through subsidence of
heavier earthy particles in a fluid menstruum, especially the waters
of the Deluge. The observed difference of materials in every
layer as well as the orderly parallelism of the layers is a sufficient
proof of this. ... At times all sorts of relics of the Deluge, fish
and vegetables occur in these shales." Scheuchzer saw in the coal
merely the remains of wood swept oft" during the deluge, " Where-
fore here and there stone coals are found which were true wood " ;
and he notes the existence of deposits at i8 to 24 yards below the
surface. This is his " Lignum fossile ex Sylva submersa."

De Jussieu,* about 1740, observed, near St. Chaumond in France,
many impressions of plants very different from those now existing.
He remarked that these represent true plants and that they lie flat
as in a herbarium. In seeking their origin he was led to believe that
they were vegetation of a warm climate and that they had been
transported. The sea covered the continents ; the currents carried
and deposited the plants and shells which are found petrified.

Few writers prior to the middle of the eighteenth century
dealt in other than a priori arguments but, after half the century
had passed, there came numerous observers whose labors were
utilized by Buft'on.

Buffon^ recognized the vegetable origin of coal and asserted that
its excellent quality is due to the intimate mingling of vegetable
matter with bitumen — the latter being only vegetable oil or animal
fat impregnated with acid. He designates coal as " Charbon de

^ J. J. Scheuchzer, " Aleteorologia et oryctologia helvetica," Zurich, 1718,
pp. no, III, 239, 240.

■'A. de Jussieu, cited from Saporta by L. Lesquereux, 2d Geol. Survey of
Penn., Ann. Rep. for 1885, p. 95.

'^ L. de Buffon, " Histoire naturelle, generale et particuliere," Sonnini
Ed., T. Qme., Paris, An IX., pp. 11, 14, 16, 35, 36, 42-46. The original pubHca-
tion was in 1778.

5

6 STEVENSON— FORMATION OF COAL BEDS. [ApHi 21.

terre " and restricts the term " houille " to " the black combustible
earthly deposits which are often found over and sometimes under
the coal beds." These are simply mold mixed with a small amount
of bitumen. The slime deposited in the sea, following the slope of
the bottom and extending at times for several leagues along the
coast is nothing other than the mold of plants and trees, which is
drawn ofif by running water. The vegetable oil of that slime,
seized bv acids in the sea, will become in time bituminous coal but
always light and friable ; while the plants themselves, drawn off in
like manner and deposited by the waters form the true beds of
charbon de terre, of which the characteristics are very different
from those of houille. the charbon being heavier, more compact and
swelling in the fire.

The dips of the coal are due to the general law of deposit in
moving water, while at the same time the materials have taken the
inclination of the surface on which they were laid down. Occa-
sionally the dip approaches the vertical, but even that great inclina-
tion gradually approaches the horizontal more and more as one
descends and at last the horizontal plane, the plateur. is reached.
A usual feature is that the thickness of a coal bed increases with
the depth and the maximum is cii plateur — which is in accordance
with the law of deposit of materials carried by water and laid down
on a sloping surface. The same law applies to other materials,
whereby is explained easily the parallelism of coal beds to each other
and to the intervening strata.

Von Beroldingen" published his work in the same year; it was
based on broad field study. Tn it the author maintained that stone
coals had originated from brown coals and those in turn from
peat. This aj^j^ears to be the first definite assertion of the peat-bog
or in situ hypothesis.

De Luc" published the same theor\- during the next }ear in the

"v. Beroldingeii. " l>co!)acIilungen, Zwcifel unci I'"ragen, die Miiicralogie
bctreffcnd," Erster Versucli, Hannover, 1778. The writer has been nnable
to find a copy of this work. It is cited by De Luc (1779), Mietzsch (1875)
and by several other authors.

'J. A. De Luc, " Lettres physiques et morales sur Thistoire de la terre
ct de rhomnic," Paris. 1779, Tome V., pp. 213-25. This 126th letter is dated
Oldcnlnirg, Scpteml)er 16, 1778.

6

I9II.] STEVENSON— FOR.AIATION OF COAL BEDS. 7

last of five letters describing the peat deposits of northern Europe.
During his journey across Germany and the Baltic he had made
many exact observations on bogs ; he had followed the great level
marshes of the shores up the Weser river to the inland moors and
had found the same general features throughout. He describes the
slipping of the swamp into the river where, by swelling, it formed
a hard dry rampart which prevented all further ingress of water to
the swamp. He notes the great flood of Jutland, due to subsidence
of the boggy area, which is covered at low tide. On the island of
Bornholm in the Baltic is a swamp, surrounded by dunes, which
shows many prostrate firs, pointing toward the center of the bog.
These trees were overthrown by wind when the peat was soft. He
observed that dry peat produces very fine trees, those growing on
the peat ramparts of Oldenburg being beautiful. His observations
led him to assert that

"The peat is the origin of the pit-coals or charbons de terre." He
states in a footnote that he had been anticipated by v. Beroldingen,
but that he had arrived at this conclusion independently while study-
ing the immense peat bogs of Bremen. He recalls that islands
had sunk below the ocean surface ; some of them might contain peat
as Bornholm. The waters would deposit matter on the peat giving
the shaly roof mingled with leaves of vegetables which covered the
peat at time of submergence. New sea deposits accumulated and the
peat, compressed, enclosed as in a laboratory, underwent further
change. He acknowledges that there may be difficulties in explain-
ing the transmutation of peat and the arrangement of some coal
beds, but he is confident that he is on the true road to the proper
explanation of the origin of coal and of its occurrence in beds.

An anonymous writer,- in 1781, sums up the peatbog theory as
presented at that time.

It is a received opinion amongst many naturalists, that coal was originally
peat moss, this fossil having been found in every intermediate state, nay,
sometimes with wood in it, and often with the marks of leaves, roots,
branches, and fruits of different plants, shrubs and trees, on the sides of
broken fragments. To this doctrine we were made proselyte's, being pre-

* " A Tour to the Caves in the Environs of Ingleborough and Settle in
the West-Riding of Yorkshire," London, 1781, p. 68.

7

8 STEVENSON— FORMATION OF COAL BEDS. [April 21.

sented with some pieces of coal that were got near the top of Whernside
and the other mountains, that seemed more like dry clods of peat moss than
coal, though distinguishable enough to belong to the latter class. The
principal difference in their composition is that coals abound with the vitri-
olic, and peat moss with the vegetable acid. The vitriolic acid is diffused
through every subterranean stratum ; hence if a quantity of earth should be
superinduced above a stratum of peatmoss, the vitriolic acid that would
ouse through, must in time change its nature and turn it into coal : the
deeper it lay below the surface of the ground, the more it would be im-
pregnated with this fossil acid, and consequently be the more inflammable.
If a stratum should lie near the top of a mountain, there is the less chance
that it should be well fed.

Williams'' was an unedticated man btit an admirable observer,
who stnnmarized in his vohtmes the results of studies in much of
Great Britam. He was a firm believer in the vegetable origin of
coal and equally in the wide extent of the Noachic deluge. Think-
ing that he could identify in some coals the wood of modern species,
he suggested that, prior to the deluge, only a small part of the globe
was inhabited and that most of it was covered with tall trees. Those
trees, swept off by the deluge, were carried by currents and deposited
in limited areas. But this hypothesis does not satisfy all the condi-
tions, for he had found coals which closely resembled peat. He
says, " I will here beg leave to propose another probable source of
coal. I believe I may call it a real one, and that is the antediluvian
peat bog," and this is followed by a discussion of peat bogs, their
structure and growth.

Williams argues strenuously against any hypothesis that the ma-
terials of the strata were formed by settling of particles from a
heterogeneous mass in accordance with gravity, for the order of the
beds is evidence to the contrary. At the same time, he finds in
the structure of coal beds evidence that most of the beds were
formed of transported timber. " I am of opinion that the ante-
diluvian timber floated upon the chaos or waters of the deluge, . . .
and that during the height of the deluge and the time in which the
greatest part of the strata were forming, the timber was preparing
and fitted for being deposited in strata of coal."

° J. Williams, "The Natural History of the Mineral Kingdom," Edin-
burgh, 2d ed., 1810, Vol. I, pp. 510, 522-525. The first edition was in 1789.

8

I9II.] STEVEXSOX— FORMATIOX OF COAL BEDS. 9

Darwin^'' adhered to the doctrine of formation in situ but with
modifications. " In other circumstances, probably where less mois-
ture has prevailed, morasses seem to have undergone a fermenta-
tion, as other vegetable matter; new hay is liable to do so from the
great quantity of sugar it contains. From the great heat thus
produced in the lower part of the morass, the phlogistic part, or
oil or asphaltum. becomes distilled and. rising into higher strata,
condensed, forming coal beds of greater or less purity, according to
their greater or less quantity of inflammable matter; at the same
time the clay beds become poorer or less so as the phlogistic part is
more or less completely exhaled from them."

Patrin,^^ cited by Parkinson, thought coal and the interposed
beds of rock due to alternating ejection of bituminous and earthy
materials by submarine volcanoes. In another work cited by
Pinkerton he describes the characteristics of coal beds, that they
have a boat-like form and that they are never single, there being
many in each coal field. He thinks the deposit must have been
made in still water. The occurrence of plant impressions in the
roof shales has led several naturalists to think that coal is composed
of vegetable remains. But Patrin thinks that this opinion presents
great difficulties. The naturalist le Blond found beds of coal near
Bogota at 13,200 feet above the sea. When the ocean reached that
height there would be islands ; and it cannot be seen how the small
quantity of vegetables, which had been brought accidentally from
those mountains, could have formed the thinnest bed of coal or
even of peat.

Hutton's^- opinions appeared in final form in 1795. They are
not always stated clearly but the confusion may not be that of the
author's mind : it may be only apparent and due to the somewhat
involved method of presenting the case. The carbon of coal is evi-
dently of organic origin. Bituminous coal and anthracite are parts

^° E. Darwin, " Botanical Garden,"' Add. X'otes. XVIL, 1791. Cited by
J. Parkinson ; not seen by the writer.

"Patrin, Art. Houille. "Diet, d'hist. Xaturelle," cited by Parkinson;
" Mineralogie, V., p. 317. Cited by J. Pinkerton in " Petrology," pp. 567, 568.

'^J. Hutton, "Theory of the Earth With Proofs and Illustrations,"
Edinburg, 1795, Vol. I., pp. 565, 566, 570, 575-581, 586.

9

10 STEVENSON— FORMATION OF COAL BEDS. [April;.!.

of a series, the latter having been derived from the former by the
influence of heat, which itself was the agent by which vegetable
matter was converted into coal. Fuliginous matter is given off
when vegetable materials are burned and it is just what is needed
to compose coal beds. There are many charred coal beds, which
have lost their volatile or fuliginous matter through subterranean
heat. The volatile matter, diffused through the water, aided in
formation of the strata, while smoke from burning bodies on the
land found its way to the sea where it settled to the bottom. But
this was not the only source. The rivers of Scotland carry brown
water from the bogs ; there must be some agency causing precipita-
tion of this browMi material, otherwise the sea would be impregnated
with oily substance. The constant perishing of plants and animals
would give a supply of oily or bituminous matter to the ocean, which
would become pure coal unless earthy stuffs be in the water, which
would render the coal impure. If the mixture be perfect and the
subsidence uniform, a homogeneous substance resembling cannel
would be formed.

Therefore, witli regard to the composition of mineral coal, the theory
is this, that inflammable vegetable and mineral remains, in a subtilized state,
had subsided in the sea, being mixed more or less with argillaceous, calcare-
ous and earthy substances in an impalpable state. Now the chymical analysis
of fossil coal justifies this theory: for in the distillation of the inflammable
or oily coal, we procure volatile alkali, as might naturally be expected.

Kirwan,^"' indignant at Hutton's generally iconoclastic views,
entered the lists evidently determined to annihilate the new doc-
trines as well as their author. He rejects the hypothesis that pit coal
is merely earth or stone impregnated with petrol or asphalt, for Kil-
kenny coal contains neither petrol nor any other bitumen. He
recognizes the vegetable origin of wood coal but maintains that it
is chemically different from mineral coal, so different as to show
that the latter was not derived from wood deposited in or out
of the sea. As further arguments, he notes features in the mode
of occurrence. Beds of mineral coal are uniform in thickness within
great areas, beds of wood coal are not ; beds of mineral coal show
parallelism, which is unknown in wood coal beds ; wood coal mines

" R. Kirwan, "Geological Essays," London, 1799, pp. 315-349.

10

I9II.] STEVENSON— FORMATION OF COAL BEDS. 11

have sudden elevations or depressions, not found in those of
mineral coal ; slips or dikes abound in true coal but do not occur
in wood coal : wood coal is frequently, genuine coal never found
in plains. Mineral coal is of distinctly inorganic origin.

Aly opinion, therefore, is that coal mines or strata of coal, as well as
the mountains or hills in which they are found, owe their origin to the
disintegration and decomposition of primeval mountains, either now totally
destroyed, or whose height and bulk, in consequence of such disintegration,
are now considerably lessened. And that these rocks, anciently destroyed,
contained most probably a far larger proportion of carbon and petrol than
those of the same denomination now contain, since their disintegration took
place at so early a period.

The seams of coal and their attendant strata must have resulted
from the equable diffusion of the disintegrated particles of the
primitive mountains carried down by the " gentle trickling of the
numerous rills " and more widely dift'used by more copious streams.
The important sources of material for the coal beds were granite
and trap, as those rocks contain natural carbon and hornblende, the
latter mineral being an extremely important source. Kirwan's argu-
ments are extremely ingenious and he finds no difficulty in explain-
ing all known phenomena by means of his " supposition."

Playfair^* attacked Kirwan's doctrine and defended that of
Hutton. He regarded Kirwan's suggestions as deserving only
ridicule. He showed that both wood and mineral coal occitr in the
same bed and that most of Kirwan's postulates were not in accord
with fact. The quantity of hornblende and silicious schist to be
decomposed in order to yield the coal would be vastly greater than
Kirwan had supposed ; Playfair suggested that it would have been
better to imagine that the diamond existed so abundantly in the
primeval mountains as to constittite great rocks. A single ridge
might suffice to give material for coal beds of all the surrounding
plains. He asserted that Kirwan's hypothesis trespasses on every
principle of common sense.

\'oigt^^ strenuously opposed v. Beroldingen's hypothesis that coal

"J- Playfair, "Illustrations of the Huttonian Theory of the Earth,"
Edinburgh, 1802, pp. 148-160.

^'J. C. W. Voigt, " Versuch einer Geschichte der Steinkohlen, der
Braunkohlen und des Torfes," Weimar, 1802, pp. 42-46.

11

12 STEVENSON— FORMATION OF COAL BEDS. [April 21.

beds originated as peat bogs. He believed that coal was formed
chiefly from the harder species of reeds, and the vegetable matter
had been dissolved in an oily substance. The fluidity of the material
is proved by the occurrence of thin streaks in sandstone as well as
by carbonaceous shale, which contains enough combustible matter
to be utilized as fuel. The opinion that stone coal was at one time
brown coal and that, in turn, originally peat deserves no considera-
tion ; it is merely the notion of a closet student and Voigt is sur-
prised that Beroldingen, who had seen so many localities of stone
and brown coal and peat, should offer the suggestion. Stone coal
belongs to the oldest formations while brown coal and peat are of
the newest ; one might as well suggest that a child begat its mother,
and the mother, the grandmother. It is sufficiently clear that Voigt
conceived that the vegetable matter was first converted into bitumen
and then transferred. His memoir was crowned by the Gottingen
academv. The prominence thus given to it as well as the emphatic
manner in which its assertions were made did much to repress the
readiness shown by contemporaries to accept the Heroldingen hypoth-
esis in whole or in part.

Faujas-St.-Fond^" discussing the source of coals occurring in
what he terms granitic regions, says that they were deposited in
bays or vast basins excavated by' the sea. Currents transported into
these receptacles materials from the granites, which became beds of
greater or less thickness. Sometimes the seas brought the plants
which, along with animals so abound in them, and these accumulated
pele mele with the products of terrestrial vegetation brought down
by the rivers. At other times the tides deposited on these beds of
combustible materials the quartz sand of the sea bottom; at later
periods, wood and plants arrived again, were deposited on the sands
or clays ; thus were formed the alternating beds of vegetable mate-
rial with combustil)le residues of fish, mollusks and marine plants.

Al. Brongniart^' described in detail the various types of coal,
lignite and ]^eat. He evidently accepts \"oigt's conclusion that there
is no bond between coal and lignite, while at the same time he hesi-

'"B. Faujas-St.-]^\)n(l, " Essai de geologic," Paris, 1803, p. 443.
"Alex. Brongniart, " Traite eleniciitairc de mineralogie avec des applica-
tions aux arts," Paris, 1807, t. 2, pp. 13, 14, 32. 36.

12

19".] STEVENSON— FORMATION OF COAL BEDS. 13

tates to accept the doctrine that coal is product of decomposition
of organized bodies. Brongniart exhibits much caution in respect
to generahzations but offers these conclusions which he thinks are
derivable from actual observation : ( i ) That the coal is a formation
contemporaneous with or posterior to the existence of the organized
bodies; (2) that this combustible, when it was deposited or formed,
was liquid, homogeneous and in a great degree of fineness, which is
proved by the frequently parallelopipedonous structure and by the
manner in which it is absorbed by the beds which enclose it; (3)
that the cause, which has deposited or formed it, was renewed sev-
eral times in the same place, with conditions almost the same; (4)
that this cause has been the same for almost all the earth, since the
coal beds present in their structure and their accessory conditions
almost always the same phenomena; (5) that these beds have been
deposited without violent disturbances, since the organized bodies
which are found in them are often entire and since the leaves, which
are impressed on the shales covering the coal, are expanded and are
hardly ever rubbed or even folded.

Parkinson^^ regarded coal as a product of vegetable matter
reduced to fluidity by bituminous fermentation ; this fluid suffered
modification of its inflammability by deposition of carbon and by
intimate admixture with various salts. The vegetable matter had
been swept into the sea by the universal deluge.

Kidd^^ summarizes the doctrine of transport thus, " Powerful
floods have swept away forests and subsequently covered them with
the ruins of the soil in which they grew ; whence those beds of clay
and gritstone which so generally accompany the coal itself." His
objections to this doctrine are that remains of trees and shrubs are
wanting; that the plants are evidently those of many places; that
the mechanical force, which uprooted the forests and swept away
the vegetable matter as well as the greater amount of the earthy
matter in the shales and gritstones, must have been extreme ; yet
the particles of the grit are not rounded and show no sign of attri-

^*J. Parkinson, "Organic Remains of a Former World," London, 1811,
Vol. L, p. 248.

^"J. Kidd, "A Geological Essay on the Imperfect Evidences in Support
of a Theory of the Earth,"' Oxford, 1815, pp. 126, 127, ij8.

13

14 STEVENSON— FORMATION OF COAL BEDS. [April 21.

tion. He objects further that the theory does not account for the
alternation of calcareous with argillaceous and siliceous beds, and
asks on what principle one may expect that beds of earth, spread out
by the floods, should be periodically calcareous, argillaceous or sili-
ceous, and how can it account for the alternations of clay beds with
numerous coal beds ; why should a second flood in its blind fury
deposit a second series of beds on exactly the same spot where the
first series is deposited?

Conybeare-° adhered to the belief that vegetable matter alone
was the source of coal and accepted Sternberg's suggestion that
torrents tore oiT the vegetation from scattered primitive islands
to deposit at the bottom of adjacent basins. He conceived at this
early date a theory having not a few of the features characterizing
one offered at a much later date. He thinks that the coal measures
were deposited in estuaries and that the partial filling up of lakes
and estuaries oft'ers us the only analogies in the actual order of
things with which the coal deposits can be compared. Respecting
the deposit at Bovey Tracy, he says :

We must here suppose the wintry torrents to liave swept away a great
part of the vegetation of the neighboring hills and buried them in the estu-
ary with the alluvial detritus collected in its course : tlie latter would, from
its gravity, have sunk first and formed tlie floor ; tlie wood would have
floated till, having lost its more volatile parts by decomposition and become
saturated with water moisture, it likewise subsided upon them, being per-
haps loaded by fresh alluvium drifted down upon its surface; the re-iterated
devastations of successive seasons must have produced the repetition and
alternation of the beds . . . and if we suppose a like order of things to have
operated more extensively and for a longer period during the formation of
the coal strata, we shall find sucli an hypothesis sufficiently in accordance
with their general ])hcnomena.

Ad. Brongniart,-^ after long study of the fossil plants, concluded
that in the Carboniferotis time the dr}- land was confined to islands
on which grew the ])lants who>e remains are in the coal formation.
Numerous proofs established that the plants grew in the very places
where they are found or, at most, within only a little distance away.

"" \V. 1). Conybearc. "Outlines of Geology of Enghuid and Wales,"
London, 1822, pp. 334, 345. 347.

■' Adolphe Brongniart. "" Prodromme d'une histoirc des vegetaux fos-
siles," Paris, 1828, pp. 183, 184.

14

I9IIJ STEVEXSOX— FORMATIOX OF COAL BEDS. 15

The manner in which the plants are preserved in rocks accompany-
ing coal beds as well as the presence of vertical stems in normal
position are most convincing. He cannot attribute the formation of
coal beds to accumulation of vegetable detritus transported from
a distance and deposited in the condition of pulp (bouillee) as was
supposed by Sternberg and Boue. In fact it would be difficult to
understand how the causes, which reduced to a kind of pulp the
plants which have formed the coal itself, failed to change the plants
found in the neighboring beds; how it is that the coal formed in
the sea contains no marine debris ; how, finally, a substance thus
deposited shows no more inequalities in thickness of the bed. He
accepts De Luc's conception of vast swamps as best agreeing with
observed conditions. The intervening rocks originated during pe-
riods of elevation of the sea-level or depression of the land.

Ure'-- could not believe that coal beds are the remains of up-
rooted forests or shattered trees. Reeds and ferns atTorded most
of the material and they grew not far from the place where the coal
is found, as is shown by the state of preservation. The vegetable
matter was reduced to a pasty condition, elaborated in the tepid
waters of the primeval globe and was deposited in a semi-fluid con-
dition where now found. The proof of this hypothesis is found in
the great extent of very thin coal beds, the parallelism of the oppo-
site faces, in the existence of narrow fissures filled with coaly mat-
ter, as well as in 'the homogeneous substance and texture and the
cubical division in coal beds. The conversion of the buried matters
into coal might continue ripening during many ages bv percolation.

AlacCulloch'--^ devoted many years to actual investigations in both
field and closet, the results being given in numerous brief papers.
The outcome of his completed studies is presented in an elaborate
discussion of the origin of coal and the formation of coal beds.

Peat, lignite and coal form a continuous series, the transition
being sufficiently perfect. The character of the plants, the presence
of tree trunks, their bark converted into coal, show that the plants
from which coal was formed were terrestrial, not marine. Those

~ A. Ure, "A Xew System of Geology," London, 1829, pp. 163-174.
^J. MacCulloch, "A System of Geology with a Theory of the Earth,"
London, 1831, Vol. IL. pp. 311, 312, 336. 337, 339, 341, 359.

15

16 STE/ENSON— FORMATION OF COAL BEDS. [April 21.

plants, bcinj,^ aquatic in t}pc, grew in low moist forests in marshes
on the borders of lakes or rivers. From the fact that peat occurs
in only limited quantity within the tropics, he argues against the
supposed tropical nature of the carboniferous plants. These em-
bedded plants are so often in such state of preservation as to pre-
clude the notion that they had been transported. MacCulloch's
study of peat bogs led him to recognize four types. Marsh deposits
are vast in area, uniting on one side with Lake deposits and on the
other with Forest deposits, as they may be on either lowland or
upland. They owe their origin ch'iehy to Sphagnum pal ust re. Two
sets of plants aid in forming the lake deposits ; shallow portions of
the lake give floating plants, which, after flowering, sink to form
a vegetable stratum ; other plants fringe the pond, detain clay and
detritus, supporting reeds and bulrushes ; these gradually advancing
form a marsh and eventually the lake is filled. The Forest peat
contains submerged wood and is produced, for the most part, by
plants after fall of the forest, so that it is a marsh peat. It is
always forming in forests and the submerged tree-trunks are almost
wholly in one direction, having been overthrown by the wind. ]\Iari-
time peat is formed in estuaries by Zostcra iiiariiia. which causes
formation of sandbanks and bars ; seaweeds may contribute even to
shore peat, for Fiicus scrratits and F. nodosus are found in deep
peat at some places in Holland. Transported peat is rare, occurring
only in small (juantities and as a fine powder ; it is due to bursting
of bogs. AlacCullocli, alter a detailed comparison of phenomena
observed in peat bogs with those observed in coal deposits, concluded
that by far the larger part of the coal deposits are now lying where
the progenitor plants grew.

jMammatt-'* appears to have been the first to recognize that an
underclay usually accom])anies coal beds. " Seams of fireclay abound
in the Ashby coal-field and there are very few coal-measures which
do not rest upon it, as the sections will show." Jle remarks further:
" From the circumstance, that so many cases occur, where a toler-
ably pure fireclay lies immediatel}- under, and in contact with, a bed

"* E. Mnniniatt, "Coal Vidd of Aslihy dc la Zouclic." 1834 p. jt,. Cited
by II. 1). Rogers, Assoc. Anier. Geol. and .\at.. Btslon. 1843 [i. 454.

16

I91I.] STEVENSON— FORMATION OF COAL BEDS. 17

of coal, it may be inferred, that such clay stratum could not have
been the soil, where grew the vegetable matter which produced the
coal, unless this vegetable matter was a moss, a peat, or some aquatic
plant; because in the clay, there is no appearance of trunks, or
other vegetable impressions, beyond slender leaves, as of a long
grass."

Lyell-^ about this time committed himself in part to both hypoth-
esis, though evidently disposed to favor that of transport. " The
coal itself is admitted to be of vegetable origin and the state of
the plants and the beautiful preservation of their leaves in the
accompanying shales precludes the idea of their having been floated
from great distances. As the species were evidently terrestrial, we
must conclude that some dry land was not far distant ; and this
opinion is confirmed by the shells found in some strata of the New-
castle and Shropshire coal-fields." The alternation of marine lime-
stone with strata containing coal beds may be due to alternate rising
and sinking of large tracts, which were first laid dry and then sub-
merged again. He is clearly inclined to agree with the suggestion
made by Sternberg and Ad. Brongniart, that the beds of mineral
detritus were derived from waste of small islands arranged in rows
and he thinks that the suggestion is supported by the observation
that the Coal Measures flora is of insular type.

At a later period, Lyell accepted the autochthonous origin of
the coal beds, as appears in the " Travels in America."

Buckland,-'' in 1836, accepted the theory of transport. " The
most early stage to which we may carry back its origin was among
the swamps and primeval forests, where it flourished in the form of
gigantic Catamites and stately Lepidodcndra and SigillaricE. From
their native bed, these plants were torn away, by the storms and
inundations of a hot and humid climate and transported in some
adjacent Lake or Estuary or Sea. Here they floated on the waters,
until they sank saturated to the bottom, and being buried in the
detritus of adjacent lands, became transferred to a new estate

^^C. Lyell, "Principles of Geology," 5th ed., 1st Amer. ed., Philadelphia,
1837, Vol. L, p. 134.

^®W. Buckland, "Geology and Mineralogy considered with Reference to
Natural Theology, Philadelphia, 1837, pp. 362, 353, 354.

PROC. AMER. PHIL. SOC. L. I98B, PRINTED APRIL 24, I9II.

17

18 STEVENSON— FORMATION OF COAL BEDS. [April 21.

among the members of the mineral kingdom. A long interment fol-
lowed, during which a course of Chemical changes, and new combi-
nations of their vegetable elements have converted them to the min-
eral condition of Coal."

On an earlier page, Buckland referred to the existence of erect
stems in the Coal measures rocks : he was convinced that none of
those recorded, aside from some near Glasgow, could have grown
where they were found.

From this date onward the discussion respecting erect stems,
became increasingly important. The facts and the conclusions are
alike contradictory. It is better to pass by this matter for the pres-
ent and to treat it apart.

Sternberg"' did not accept the hypothesis that coal was formed
from peat. He thought that one should conceive of a forest in the
ancient time, when neither man nor plant-eating animals existed ;
that this forest grew for an indefinitely long period in a warm,
humid climate ; that the offal of buds, leaves, seeds, fruits and
decayed stems accumulated on the ground ; many generations of
plants grew, one on the other, and so a mass, consisting of mold
from wood, fruits, seeds, leaves, with complete examples of smaller
plants, would be produced, whose surface would be covered with
still living vegetation. Conceive now of a cataclysm, when a hurri-
cane casts down the living plants and is followed by a flood, loaded
with sand and mud — thus one has a true picture of the mode in
which the overlying deposits of the stone coal are formed. Cases
are rare where one finds erect stems of trees between two coal beds,
losing themselves above and below in the coals.

The water-cover would hold the mold in place, would bring
about decompositions and changes in the different materials and
would cover the whole with clay and sand. It is unnecessary to
borrow carbon from the air or water in order to get a coal forma-
tion, since in this interval, as well in the dry as in the wet way,
humus and other acids, bitumen and coal itself have been produced,
as occurs even to-day in peat bogs. The material existed in abun-

^ K. Sternberg, '" Versuch einer geognostisch-botanischen Darstellung
der Flora der Vorwclt," Siebenstes und achtes Heft, Prag, 1838, p. 88.

18

I9II-] STEVEXSOX— FORMATION OF COAL BEDS. 19

dance and fermentation necessarily followed under the covering of
water and sediment. It is unimportant to determine whether the
water was fresh or salt.

In this wav, he sees no ditificulty in accounting for accumula-
tion of stone coal deposits, even those of Saint-Etienne. which are
60 fathoms thick. He emphasizes the fact that the particular vege-
tation of the stone coal period produced colossal stems.

Link-® was the first to study the texture relations of coals. He
observes that two theories had been offered to account for the origin
of coal beds ; that of driftage does not commend itself to him, but
that referring the coal beds to ancient peat bogs appears more rea-
sonable. After summarizing the opinions of v. Beroldingen, de
Luc, Steft'ens, Hutton and Leonhardt, he presents the results of his
own investigations. \'on Buch, feeling perplexed by some recent
publications, had given him some specimens of coal from Bogota
and had asked that he study them microscopically. The composition
of one of those coals so resembled that of peat that he was led to a
wide study of coals and peats from several horizons and regions.

In all peats, whether loose or compact, cell tissues form the
body of the mass ; the dift'erence in ciuality of the peats being due
probably to dift'erence in the plants ; the stone coals resemble peat
in structure, some recalling the comparatively loose LiniDii peat
used as fuel in Berlin, while others are more like the dense, almost
wood-like peat from Pomerania; the Mesozoic coals vary, one from
the ]\Iuschelkalk closely resembles peat, but the Liassic coals appear
to be composed largely of woody fiber; the brown coal of Green-
land is like the LiniDii peat, while that of ^leissner in Saxony is
similar to the dense Pomeranian material.

Link observes two quarto plates illustrating the vegetable struc-
tures observed in each of the peats and coals examined.

Logan's-^ notable memoir on underclays appeared in 1841. He

^ H. Link, " Uber den Ursprung der Steinkohlen und Braunkolilcn nach
mikroskopischen Untersuchungen,"' Abliandlnngen d. k. Akad. d. Hiss.
Berlin. 1838, pp. 33-44-

^W. E. Logan, "On the Character of the Beds of Clay Lyhig Immedi-
ately below the Coal Seams of South Wales," Proc. Geol. Soc. London,
Vol. III., pp. 275, 276.

19

20 STEVENSON— FORMATION OF COAL BEDS. [April 21.

had found almost one hundred coal beds in the South Wales coal-
field and. with rare exceptions, each overlies a clay bed from six
inches to ten feet thick. The clay varies much in composition but
it is a persistent deposit, so that coal beds which have thinned out in
the workings have been found again by following the clay. Ordi-
narily. Stigmaria occurs abundantly in the clay and Logan thinks
that plant was the source of most of the coal.

Soon after the field work of the Virginia and Pennsylvania sur-
veys was completed, H. D. Rogers''" gathered the salient facts bear-
ing upon the origin of coal beds and presented them in a paper
which has become classical. It bears the impress of the time, but
it was based on broad observations by the author and his equally
celebrated brother, William B. Rogers, aided by a corps of able
assistants ; the studies, lasting six years, were in detail for an area
of somewhat more than 20,000 square miles, but in addition less
detailed studies had been made in Ohio and Kentucky, so that the
region under consideration was not far from 40,000 square miles.
The discussion was the first serious attempt to account for the origin
of the Coal Measures, which was based on actual study of a vast
area.

At the outset, Rogers pronounced against any theory of delta
formation, as according to his belief the Appalachian ocean deep-
ened toward the west and northwest. ^^ The deposits are traceable
coastwise for 900 miles, so that it seems improbable that fluviatile
currents could have assembled them.

The sandstones decrease in thickness and coarseness as they re-
cede from the ancient shoreline at the east ; the shales increase in
that direction for a time and then decrease, while the limestones,
wholly wanting near the shore line, increase in thickness and purity
so as to become imposing before the Ohio River has been reached.
The animal remains found in the limestones are marine. There

'° H. D. Rogers, "An Inquiry into the Origin of the Appalachian Coal
Strata, Bituminous and Anthracitic," Reps, of Amer. Assoc, of Geologists and
Naturalists, Boston. 1843, pp. 434, 459, 463-467.

^' It should be noted here that wlicn Rogers wrote the conditions on the
west side of the Appalacliian l)asin were not known; but does not affect the
general argument.

20

19"-] STEVENSON— FORMATIOX OF COAL BEDS. 21

were many alternate periods of movement and of total or compara-
tive rest. Limestones indicate periods of comparative tranquillity.
Some of the coal beds are of great extent. The Pittsburgh bed had
been traced around an area of 14,000 square miles and there are
isolated basins holding that bed far southeast from the main area,
so that the Pittsburgh coal must have covered a surface of not less
30,000 square miles. The uniformity in thickness and the absence
of abrupt variations are as remarkable as the area. These features
" seem strongly adverse to the theory which ascribes the formation
of such deposits to any species of drifting action."

The alternation of laminae of bright and dull coal ; the lenticular
form of the bright layers ; the predominance of mineral charcoal in
the dull laminae seem to be almost conclusive arguments in favor of
belief that the vegetable matter grew where it was deposited. He
finds it difficult to understand why the coal does not consist principal-
ly of the larger parts of trees if any drifting agency brought the
materials together. The leaves and smaller parts would be detached
before the trunks could become waterlogged.

But the beds have subordinate divisions, coal, clay, impure coal,
so persistent in great areas that miners can recognize their bed at
great distance from their own locality ; only one method of accumu-
lation can explain this. " I cannot conceive any state of the surface,
but that in which the margin of the sea was occupied by vast marine
savannahs of some peat-creating plant, growing half immersed on a
perfectly horizontal plain, and this fringed and interspersed with
forests of trees, shedding their offal of leaves upon the marsh. Such
are the only circumstances, under which I can imagine that these
regularly parallel, thin and widely extended sheets of carbonaceous
matter could have been accumulated." The purity of the coal is
inconsistent with any notion of drifting of the vegetable matter,
"which according to any conceivable mode of transportation, would
be accompanied by a large amount of earthy matter, such as abounds
in all delta deposits and even mingles with the wood as in the raft
of the Atchafalaya."

The underclay, irregular in structure, accompanies nearly every
coal bed in the Appalachian basin and usually contains Stiguiaria

21

22 STEVENSON— FORMATION OF COAL BEDS. [April 21.

ficoidcs with its fibrous processes. The roof contrasts with the
underclay and is, normally, a laminated shale due to more or less
rapid current and it contains va^st numbers of plant impressions.

When the roof is sandstone there is evidence of tempestuous cur-
rents and the vegetable fragments are trunks and stems of large
plants. Occasionally limestone forms either roof or sole of the coal
bed but there is usually a very thin layer of calcareous shale parting
them.

No hypothesis, thus far presented seemed satisfactory to Rogers,
and he presented his own to account for origin of the Coal Measures.

He imagined extensive flats bordering a continent, the shore of
ocean or bays, beyond which was open sea. The whole period of
the Coal Measures was characterized by a general slow subsidence
of the coasts, interrupted by pauses and gradual upward movements
of less frequency and duration, and these merely statical conditions
alternated with great paroxysmal displacements of the land. During
gentle depression, the coast was fringed by marshes while arborescent
plants were on the land side. The meadows would give pulpy peat;
leaves blown in or moved by higher tide would rest on the peat ; some
would be buried and become pulpy, or, in some cases, by rapid re-
moval of volatile constituents would remain as mineral charcoal. An
earthquake comes. Water is drained from the swamps and their
tributaries ; muddy water draws from swamp and swampy forests
leaves -and the rest to distribute them with the mud over the bog.
This is the laminated shale. The sea returns, rolls over the swamp
to the dry land ; withdrawing, it brings uprooted trees, and washed
ofif soil, strewing the land stuiT in a coarse promiscuous stratum.
Repeated waves would add to the mass. The disturbance ends;
coarse materials sink, then the less coarse and last of all the finest
sediment, light vegetable matter and the buoyant stems of Stigmaria,
would sink together. A new marsh would be made and once more
the savannahs would be clad with vegetation. This he terms the
paroxysmal theory.

Petzholdt"- found two questions involved in the problem; were
coal beds formed during a brief period and were they formed in situ

^'A. Pclzholdt, "Geologic," Zweite Auilage, Leipzig, 1S45, pp. 413-417.

00

I9II.] STEVENSON— FORMATION OF COAL BEDS. 23

or from transported vegetable material. The answer to the first
question is certain — a great period of time was required for forma-
tion of the coal beds and their associated strata; but the second
question is more complex and he is inclined to believe that both
methods are possible, though there may be difficulty ip determining
which prevailed at a given locality. Vertical stems are not decisive,
for they are found at times in rocks formed by transport, while
prostrate stems occur in deposits clearly made in situ.

He believed that there were no continental areas during Carbonif-
erous times, that the dry land consisted only of islands. For this
reason, it is impossible to accept the hypothesis that coal was formed
in great lakes or at the mouths of rivers. The only method of
formation by transport would be the driving of great masses of
vegetable matter against an island, which would collect in the quiet
eddy on the opposite side, where, becoming waterlogged, they would
sink and be covered with mud. He clearly prefers the doctrine of
origin in situ.

An island, heavily forested for an indefinitely long period, be-
comes covered by a mass of bark, wood, etc., and similar remains
of small plants. If the island be flooded by the outburst of granite
and consequent elevation of the sea-level, the vegetation will be pro-
strated. By frequent outbursts the sea-level will be raised perma-
nently and the island remains submerged. Deposits of sand and mud
bring the island again to the surface of the water : a new forest rises
on the grave of the old one. He thinks the alternation of strata and
the formation of coal in situ can be explained very simply in this
way.

IMurchison,-"^ after his study of the Donetz field in Russia, was
convinced that the doctrine of transport alone could explain the
conditions. The sections in southern Russia show "that the hypo-
thesis of the formation of coal beds by masses of vegetation which
there grew having subsided //; situ (the truth of the application of
which to some basins we do not deny ) cannot be applied to the cases
in question any more than to the pure marine coal beds of the north-
ern districts, Northumberland and the northwestern parts of York-

^' R. L Alurchison, " The Geology of Russia in Europe and the Ural
Mountains," London, 1845, Vol. L, pp. 112-114.

23

24 STEVENSON— FORMATION OF COAL BEDS. [April 21.

shire, etc." Limestones with marine fossils are found at various
horizons in the Donetz section. The presence of an underclay proves
nothing — even though Stigmaria ficoidcs be the only plant present
for a confused assemblage of plants is seen above and below the coal
beds and the fossil beds are exclusively marine. The fine underclay
indicates only that the sea bottom was covered with detritus of plants
washed in by floods ; the heavier earthy matters, accompanying the
detritus, sank to the bottom, while the plants floated and formed the
upper stratum. Those plants, thus left on the muddy slime, were
covered afterwards by other sediment. ]\luch of the coal, in strata
alternating with marine sediments, may have come from the wash-
ing away and sinking into the sea of floating masses of matted earth
and plants.

At a later date,^* he discussed the question more broadly. He
refers to the terrestrial conditions exhibited in the Upper Carbonif-
erous of England and to the lack of a physical break there between
the Lower and the LTpper Measures, such as appears in Germany and
France. In those countries, the later accumulations may well be
accounted for by depressions of low woodlands and jungles beneath
freshwater, followed by elevations and depressions. There is no
physical break in Britain, but there is the same passage from
marine to terrestrial conditions, of which the coal beds offer posi-
tive evidence; for the roots of SigiUaria are found in the underclay,
which was the soil of a primeval marsh or jungle. The view, which
supposes many and successive subsidences of vast swampy jungles
beneath the level of the waters, best explains how the different
organic masses became so covered w^th beds of sand and mud, as to
form the sandstone and shale of such coal fields. But this theory of
oscillations . . . can scarcely have an application to those other
seams of coal, which, as before mentioned, are interstratified with
beds containing marine shells, the animals of which, such as Prodiicti
and Spirifcrs, must have lived in comparatively deep water."

He conceived that the latter class is to be explained only by
the supposition that great rivers, flowing through lowlands, trans-
ported vast quantities of trees, etc., entangled in earth, and de-

^* " Siluria," 3d ed., London, 1859, pp. 315-317.

24

19"] STEVEXSOX— FORMATION OF COAL BEDS. 25

posited them on the bottom of the estuaries, or that vast heaps of
organic matter were carried as floating masses to the sea. The
Northumberland deposits, large tracts of Scotland, as well as the
Donetz field in Russia offer fine proofs of these conditions. There
were at least two modes in which coal measures were formed, one
terrestrial, the other subaqueous.

Goeppert^^ in his elaborate work on the formation of coal beds
gave the results of many years of study in the Silesian coal fields.
A large part of the volume is devoted to determination of the
materials forming coal ; it will be considered in another connection.
The chapter on the formation of coal beds is supplemented by a
mass of illustrations drawn from the coal fields of Silesia, the whole
discussion being so compact, so free from unnecessary detail that
to make a just synopsis is difficult. The standpoint in Goeppert's
w'ork differs much from that in the discussion by Rogers, the only
preceding study with which it can be compared. Rogers knew
little about the intimate structure of coal itself and reasoned wholly
from stratigraphical conditions ; Goepert was a skilfull palseobotanist
as well as stratigrapher.

The important question for Goeppert is, were the coal beds
formed of plants growing in place or of plants brought in from
other localities.

There were many islands, mountains, valleys, rivers, etc., in the
Coal Measures time. The organic matter was deposited on plains
which were covered w-ith sand, clay or mud. The extent of the
deposits, their occurrence as plains or as basins show that they
were laid down on the sea-bed, on slowly changing coasts or in
enclosed sea or lake basins. The few marine products found in
coal beds do not favor the opinion that the coal- forming material
was collected from distant places and deposited in the depths of
bays ; everything indicates the utmost quiet ; the vegetation covered

^■^ H. R. Goeppert. " Abhandlung eingesandt als Antwort auf die Preis-
frage — ' Man suche diirch genaue Untersuchungen darzuthun, ob die Stein-
kohlenlager aus Pflanzen entstanden sein, welche an den Stellen, wo jene
gefunden werden, wachsen ; oder ob diese Pflanzen an anderen Orten lebten,
und nach den Stellen, wo sich die Steinkohlenlager befinden, hingefiihrt
wurden?" Amsterdam, 1848, pp. 119-131, 136-139, 141-160, 278, 279.

25

26 STEVENSON— FORAIATION OF COAL BEDS. [April 21.

the low-lying horizontal sea-strand. Changes of level, elevation and
subsidence, led to burial of the plants under the ocean ; sand and
clay were deposited on the plant covered surface ; dunes were
formed, on which plants grew to run the same course. Through
repetition of this process, the different beds were formed, separated
by sand and clay. The conditions were like those of the present
day, for submerged bogs and forests have been observed at many
places along the coasts of Europe and America.

Well preserved stems are wanting because the plants lacked a
dense interior structure. Filled stems are rare in Tertiary deposits
because the trees were dicotyledonous ; whereas they abound in the
Coal Measures because the loose interior structure decayed quickly.
Plants grew in these hollowed stumps ; Goeppert found Lepido-
dendron, Calaniitcs and ferns in decayed SigiUaria; in the stump
of Lepidodcndroii he found the stem of a new genus, two feet long
and vertical.

If the coal had become compact or if the quiet were undis-
turbed, the boundary between coal and the succeeding deposit is
sharply defined ; at most one finds only impressions of stems lying
upon the upper surface. This latter condition occurs frequently in
Upper Silesia, where the coal is composed chiefly of Sigillaria. It
is cjuite true that filled stems occur even within the coal itself;
Goeppert found them. He explains their presence by supposing
that clay and sand were brought down by floods before con-
solidation of the coal, before the spaces between the stems had
been obliterated by compression. In the same way he accounts
for Brandschiefer or bituminous shale ; the influx of muddy waters
caused the alternation of laminae of bright coal, containing 2 per-
cent of ash, with dull layers, containing much mineral charcoal and
20 to 25 percent of ash.

The overlying beds were deposited after complete formation of
the coal bed and the time-interval between the two d^osits is as
variable as the intervals interrupting the formation of a coal bed
itself. Partings in coal beds show how the time required for dif-
ferent types of deposits may vary. A parting, ten inches thick, may
be equivalent in time to a sandstone deposit elsewhere, many fathoms

26

19".] STEVENSON— FORMATION OF COAL BEDS. 27

thick. Perhaps one may regard layers containhig great abundance
of plants as equivalent to deposits in which the plants do not
form beds, because in the latter case the plants were brought in con-
temporaneously with the sand and mud masses. He is convinced
that the coal and the enclosing sandstone or shale beds are wholly
independent deposits. And this belief is strengthened by the fact
that the material, filling stems in coal, clay or sandstone, differs
from that which surrounds them — an additional evidence of the
extreme quiet prevailing during deposition. Goeppert was the first
to recognize that the coating of the filled stems is the converted
bark. The roots of Sigillaria and Lcpidodcndron were feeble, as
are those of related plants to-day, and the trees were overthrown
easily ; and thus it happens that the stems, as in Upper Silesia, con-
tribute to the formation of the coal. When overthrown, their cel-
lular interior was squeezed out and converted into coal, as is seen
near Dombrowa. All the phenomena indicate that the coal deposits
were made during conditions of quiet, which would be impossible
unless the plants grew where the coal is found.

The vast extent and constancy in structure exhibited by coal beds
is important. He cannot think that such a mass could be floated in
at once, yet how could it be deposited so regularly by any other
means? He agrees with Lindley and Hutton and wath Burat that
the mass is too great for transport. He is unable to believe that
the coal was the product of forests, because the amount is so vast ;
but the evidence satisfies him that the plants have not come from a
distance. He prefers to accept the opinions presented by v. Berold-
ingen, De Luc, Ad. Brongniart, Link, and to believe that, if not all
coal beds, at least the thickest originated as peat bogs — the more so
because of the resemblance which a buried peat bog has to a coal bed.

He conceives that on the damp floor there grew lycopods, cala-
mites, ferns, stigmaria and other plants, corresponding to the crypto-
gams and monocotyledons of present day bogs. Tree-like Sigillarice
and Lcpidodcndra grew on the borders of the bog and at times were
uprooted by floods. He laid great stress on the preservation of the
plants, as precluding the possibility of transportation ; he finds the
mode of decay of tree stems equally important, for the conditions
observed in Calamitcs are the same with those found in his experi-

27

28 STEVENSON— FORMATION OF COAL BEDS. [April 21.

mcnts with Arum. The presence of vertical stems is noteworthy
because they are so numerous. It is possible for floods to carry
away whole trees and to deposit them in vertical position ; that oc-
curred in the great debacle near Martigny in Switzerland. This
explanation would suffice for an isolated instance ; but the number of
such stems in the Coal Measures is too great ; the analogy is in
submerged forests of our own day.

The distribution of plants, both vertically and horizontall}', has
an important bearing on the subject. At one locality the flora may
consist almost wholly of one species and at another, almost wholly
of another species. There is a group-like distribution, so to speak,
a social occurrence. In Upper Silesia, the coal may be termed
Sigillaria coal, while in Lower Silesia it is Siigmaria coal. He
asserts that an observer, in viewing the coal bed, involuntarily thinks
of a peat bog.

Lyell's volumes on his second visit to the United States appeared
at this time and had material influence in moulding public opinion.
They will be cited in another connection.

Naumann"*" recognized the distinction between deposits formed
on the sea border and those in fresli-water lakes, as had been done
by Elie-de-Beaumont and Burat. The former contain, especially in
their lower portions, rock layers with organic remains correspond-
ing to the marine mode of formation, while the latter, less extensive,
have no traces of marine fossils or anvthing else to show co-working
of the sea. These types he terms paralisch and limnisch. These
terms are equivalent to pelagic and mediterranean of Elie-de-Beau-
mont, to terrains houillers dc Iiautr iiicr and terrains houillcrs des
lacs of Burat. The coal deposits of Great Britain, Belgium, West-
phalia, Russia and America are paralisch or pelagic ; those of central
France, Saxony and Bohemia are limnisch or lacustrian.

The prevailing rocks of the Carl)oniferons are conglomerate,
standstone and clay shale, wliicli occur in paralisch and limnisch
alike. They are derived most!}' from destruction of other rocks
and their materials were transported. The land consisted not of
small low-lving islands but mainly of great islands and continents

^" C. F. Naumanii, "Lclirlnich cUr (Jeognosic," Leipzig, 1854. VdI. II., pp.
45 r> 452, 571-580.

28

191 1.] STEVENSON— FORMATION OF COAL BEDS. 29

with mighty rivers, along whose coasts and in basin shaped depres-
sions was deposited the vast system of sand and mud strata: This at
length became marshland, ofifering the ground for the luxuriant
vegetation of the first coal bed. In the Appalachian region, there
may have been the flat coast of a land extending far to the east,
from which great rivers carried sand and mud into the shallow sea
at the west, in which, farther away, limestone was forming. Proc-
esses such as those now seen in the Nile, Mississippi, Hoangho
and other rivers, continuing for many thousands of years, would
raise the sea bed until it reached the water surface as a wide-spread
marshland. Similar operations were going on in freshwater basins
of the dry land leading to the formation of morasses, supporting
Calamites, SigUIaricc and other Carboniferous plants, which would
give a deposit of peat.

The alternation of a great number of coal beds with thick masses
of sandstone and shale is not so easily explained as is the origin
of the first coal bed. The causes in paralisch areas are difi^erent
from those in limnisch basins.

Lyell, Lindley and others held the opinion that seacoasts, on
which paralisch deposits were formed, underwent slow subsidence
during Carboniferous time. If one suppose that this subsidence was
interrupted periodically, we have a mechanism by which the forma-
tion of successive coal beds could be explained. A similar result
would be secured by occasional elevations of the sea-bottom, ac-
cording to Petzholdt's conception. There is necessary in each case
a general rise of the sea-level to cover the plant deposit with the
sandstone and shale needed to give another swampy surface. This
alternating subsidence and stability of the sea-bottom explains why
the shale, covering coal beds, encloses a mass of plant remains
and also why paralisch territories may have many but thin coal
beds.

This explanation is not wholly satisfactory for limnisch areas,
since one can hardly suppose that all of those could have suffered
the repeated subsidence. One must conceive that between longer
periods of stability there were epochs in which increased fall of
inflowing streams or a diversion of flow occurred. The greater
carrying power of the streams would bring the plant deposit and

29

30 STEVENSON— FORMATION OF COAL BEDS. [April 21.

at length form a new surface on which vegetation would begin once
more. This would give a smaller number of beds. The, at times,
great thickness and the frequent irregularity of coal beds in lim-
nisch areas may be explained in part by supposing that they were
not formed wholly as peat deposits, luit received masses of uptorn
vegetation, swept out by floods, and this leads to the question of
the formation of a particular coal bed.

There are two theories, transport (Anschwemmung) and in situ
(an Ort und Stelle). Both may be correct. The great beds, be}ond
doubt, are of in situ origin, but there are many deposits which can
be explained only by transport of plant masses.

It is known that streams bring down astonishing quantities of
plant material; that ocean currents carry driftwood far and that
it accumulates in vast masses on shores. Currents of the olden time
must have been similar. If the widespread masses were buried
under sediments, they would be transformed into coal beds. Neu-
mann thinks that repetition of this process at mouths of streams in
lakes or on the sea-coast would give a system of strata like the
present series of coal beds with intervening sandstones and shales.
Such drift masses are irregular in extent and thickness, often as
blocklike masses. Such transported material would give conditions
like those observed in coal beds of some limnisch areas, great irregu-
larity and variation in thickness, breaking up into separate benches,
some of them cxcessvely thick. He thinks that under especially
favorable conditions a coal bed might be formed in this way which
would resemble one formed in situ. He considers also that this
theory of transport explains many regular coal beds, such as those
between limestones or other strata distinctly marii;e, as well as beds
resting directly on granite, limestone, etc., without an underclay.
He. agrees with Murchison that in some cases the transport theory
has value.

But for the greater part of the coal beds, the in situ theory must
be accepted ; their material was produced by vegetation an Ort und
Stelle. All beds continuous over great areas, with regular and not
too great thickness and with a stigmaria-filled underclay are to be
explained in this way. But one must not think that there were
real forests, which were thrown down in place, compressed by in-

30

19II.] STEVENSON— FORMATION OF COAL BEDS. 31

coming sediments and changed into layers of plant material. The
Carboniferous was not a tree and forest flora ; it was morass and
strand vegetation, developed on great emerging plains of marshland.
The prevailing forms suggest that formation of the widely extended
coal beds was analogous to the formation of peat bogs.

The purity of coal substance, the continuity of the beds, their
regular thickness, the arrangement in benches due to clay layers
produced by inconsiderable inundations, the upright plant stems and
all the remaining relations of most coal beds appear to find sufificient
explanation only in this or a similar conception of the mode of their
formation. When at length a permanent elevation of the sea-level
comes, the bog is buried under sand and mud, in whose first layers,
just as in the last conditions of peat vegetation, a great mass of
plant remains is found, torn from the neighboring land ; so that it is
clear that the roof shale of a coal bed encloses as a rule a large
number of isolated plant remains.

Newberry's^" attention was attracted to the canncls and semi-
cannels of Ohio at the beginning of his studies. Observations
made in peat bogs of this country and Europe led him to believe that
cannel was formed in lagoons, where completely macerated vegetable
tissue, probably parenchyma for the most part, accumulated as vege-
table mud. Among other arguments favoring his hypothesis, he
urges that cannel is more nearly homogeneous than cubical coal ; that
it contains morp volatile matter, with more hydrogen, and must have
been deposited .n a hydrogenous medium which prevented oxidation;
that it contains aquatic animals, so abundant at times, as to prove
that they inhabited pools in which cannel was a sediment; that the
plant remains in cannel are usually skeletonized ; and that in open
water lagoons of modern peat marshes, fine carbonaceous mud ac-
cumulates, which when dried is very like cannel.

Le Conte'^^ compared the peat bog and estuary theories. The
arguments in favor of the peat bog theory are, the purity of the
coal, the fine preservation of the tender and more delicate parts

^' J. S. Newberry, Amer. Journ. Sci., 1857. A synopsis of this paper with
some additional notes was given by him in Geol. Survey of Ohio, Vol. II.,
1874, p. 125.

'^Joseph Le Conte, "Lectures on Coal," Ann. Rep. Smithsonian Inst, for
1857, Washington, 1858, pp. 131-137.

31

32 STEVENSON— FORMATION OF COAL BEDS. [April 21.

of plants, the position of these plants in the roof shale, the com-
pletely disorganized condition of materials in the coal, the presence
of the underclay, with roots and the occurrence of vertical stems
rooted in the underclay. The chief objection to the theory is the
repeated alternation, in the same locality, of coal seams with marine
and freshwater strata. There being as many as one hundred coal
seams, it would appear as though the same spot has been raised
above water level and had been depressed below it at least one
hundred times.

The estuary theory was proposed to avoid this difficulty. As an
estuary at the mouth of a great river is occupied now by salt- and
again by fresh-water, it should contain alternating deposits of marine
and fresh-water origin. In seasons of freshet, the salt water is
pushed out and the river water, loaded with mineral detritus and
timber rafts, makes its deposits ; during low water, the sea returns
and marine deposits follow.

Le Conte finds insuperable objections to the latter. He thinks
that coal beds were formed as peat bogs at the mouths of large
rivers. The analogy is to be sought, not in the bogs of Ireland,
but in those of the Mississippi delta. He supposes a vast delta,
with spaces protected by fringes of plants from influx of river muds.
There pure vegetable matter would accumulate until during some
violent flood the barrier would be broken down and the whole space
covered by mud. The delta, like that of the Mississippi, subsided
slowly and the covering of mineral detritus eventually became
ground for a new marsh. If the subsidence were more rapid than
the river deposits could overcome, the sea would take possession
and limestone would be formed. There is no necessity for con-
ceiving repeated upheavals and depressions. '* Coal has almost cer-
tainly accumulated in situ in extensive peat swamps at the mouths
of large rivers, upon ground which was slowly subsiding during the
whole period."

Lesquereux,''^ after long study of peat bogs in Europe, came to
the United States, where as palaeobotanist to several official sur-

'"' L. Lesquercux, PaLxontological report on fossil flora of the Coal
Measures, Third Ann. Rep. Geol. Survey of Kentucky. Frankfort, 1857, pp.
505-522.

32

I9II.] STEVENSON— FORMATION OF COAL BEDS. 33

veys, he examined coal beds within a large part of the Appalachian
and Mississippi coal fields. His first report upon the work in Ken-
tucky is prefaced by discussion of matters relating to the origin of
coal beds as illustrated by conditions in the i\ppalachian basin.

Bog plants are partially immersed and ordinarily are woody.
The trees are mostly resinous and are such as can thrive only in
bog conditions. The Coal Measures plants are ferns, clubmosses,
horsetails, reeds and rushes, in character much resembling the forms
prevailing in modern bogs. The peat of the Great Dismal and Alli-
gator swamps rests on white sand and fills the depressions, while
its surface is covered by canes, reeds and shrubs ; where there is
a cover of water, the soft black mud supports cypress and magnolia,
and a great mass of material is added each year. Some ponds were
once covered with vegetation, now sunken, as in Lake Drummond,
which has at its bottom a forest, probably carried down by its own
weight. He found similar phenomena in Sweden, Denmark and
Switzerland. The water, to permit formation of peat, must have a
constant level and be stagnant. The clayey bottom of bogs was
made by fresh-water mollusks and infusoria or by Characece and
Conferva:. Peat always has this mud.

Comparing these conditions with those prevailing in the Coal
Measures, Lesquereux finds : ( i ) The fireclay varies in thickness,
color, composition and in the quantity of Stigjiiaria; sometimes no
coal rests on it — the soil was ready but conditions did not favor
accumulation. Yet fireclay, without coal at one place, is likely to
bear coal elsewhere. (2) The coal varies abruptly in physical and
chemical features, just as peat varies in all directions, horizontal and
vertical ; and these variations depend largely on the plants con-
cerned as well as on the amount of foreign matter introduced. (3)
The roof shales, usually very fine, are evidence of slow subsidence,
sometimes without marine invasion, as shown by plant remains:
sometimes with marine invasion, as where the shales contain shells
of brackish water type. (4) The limestones, equivalent to or con-
tinuation of the shales, need quiet deep seawater. Influence of the
sea is very distinct in erosions due to currents. (5) The sandstones
were due in many cases to turbulent waters, as appears from the

PROC. AMER. PHIL. SOC, L, igSC, PRINTED .\PRIL 24, I911.

33

34 STEVENSON— FORMATION OF COAL BEDS. [April 21.

erosions and the mighty erect trees. The sand may have been
derived possibly from dunes such as those on the Rhine or Elbe.

Lesquereux knows of no peat composed of fucoids and marine
plants.

Jukes's'*" contribution to the discussion is not less important
than those by Rogers and Goeppert, as it is the first presentation of
the transport theory based on careful observation in an extended
area. It covered the ground so thoroughly that little aside from
detail or local coloring has been added since its publication.

Two opinions exist respecting the origin of coal beds ; the first
is that trees and plants were drifted into lakes, estuaries and shallow
seas, where, becoming waterlogged, they sank to the bottom and
became covered by the other accunudations ; the second is that the
plants were not drifted but grew and perished on the spot where
they have formed the coal, just as our peat bogs would form coal
if long buried under a great mass of earthy matters. While he does
not purpose to range himself as an advocate of either opinion, he
finds difficulties in the way of the latter which make him hesitate
to accept it exclusively. These, observed in the South Staffordshire
coal-field, he gives in detail.

1. The "rolls," "swells" or "horsebacks," which are ridge-like
accumulations of clay rising sometimes eight feet above the floor,
cannot be explained if the coal were formed at or above the level
of the water; but if coal and " ^well " alike were formed under
water no difficulty exists.

2. The " rock faults " in the Thick coal. These are of two
kinds. One, which he has not seen, is due to erosion of the coal
after deposit, the hollow being filled with the material deposited on
the coal. The other comes from contemporaneous deposition of silt
or sand with the coal, so that they alternate at short intervals. The
coal encloses cakes, layers or masses of sandstone, more or less inter-
mingled with it. One such " fault " seen by Jukes, was 286 yards
wide and it had been followed 400 yards without reaching the end.
The upper part of the coal Ijed passes over the sandstone. At the

■■'J. B. Jukes, Memoirs. Geol. Survey of Great Britain. "The South
Staffordshire Coal-tiekl,"' _'d cd., London, 1859, pp. 34-42, 44-49, 201-206.
The writer has not seen the first edition, published at least ten years earlier.

34

19".] STEVEXSOX— FORMATION OF COAL BEDS. 35

lateral border, both coal and sandstone split up so as to interlace.
The condition is precisely similar to a cake of sandstone in clay.
Jukes asks, if the sandstone was deposited in water, why not the
coal also, for they are interstratified. The partings of sand in
coal beds are of the same type. The laminae of coal are obviously
lamina of deposition ; their arrangement and their alternation with
films of shale or with thicker partings of clay or sand would all be
explained by the gradual deposition of lamin?e and strata of dif-
ferent kinds of substances and by different degrees of mingling at
the bottom of some body of water.

3. The extreme bifurcation of some coal beds; and here are
phenomena extremely perplexing from the standpoint of the in
situ theory. The great bed near Dudley, known as the Thick coal,
is composed of numerous benches, each with its own persistent
peculiarities. At two miles north from Dudley there are eleven
benches, with 36 feet 6 inches of coal and 2 feet 11 inches of part-
ings ; while at one mile east from Dudley, there are thirteen benches
with 28 feet 7 inches of coal and i foot 9 inches of partings. But
at two miles east of north from Dudley, the upper two benches,
there known as the Flying Reed coal, are at 84 feet above the Thick
coal ; at two miles farther, the interval has increased to 204 feet,
while an intercalation of 10 feet appears midway in the Thick coal
below. The benches retain their distinctive features throughout.
Similar conditions prevail toward the west, where the interval be-
tween the Flying Reed and the other portion of the Thick coal
increases from almost nothing to 128 feet within barely three miles.

There is a higher bed known as the Brooch coal. It is 95 feet
above the Flying Reed, where that bed is 10 feet 6 inches above the
Thick; but where the latter interval becomes 115 feet, the former is
only 30 feet. Thus, while the Brooch and Thick are rudely parallel,
the Flying Reed is oblicjue between them.

The normal section persists in the central southern part of the
field to some distance south from Dudley ; but toward the southwest
the Thick coal breaks up, loses its structure and becomes worthless ;
toward the southeast, the bed thins out, has little good coal and is
troubled by " rock faults"" or "cakes of sandstone."

35

36 STEVENSON— FORMATION OF COAL BEDS. [April.:.

An additional difficulty is found in the expansion of the Thick
and other coal beds toward the north. The expansion of the whole
series and the splitting of the beds in that direction seem incom-
patible with the idea that the coal beds were formed at or above
the surface of the water, while the intervening strata were deposited
under it. Of the intervening rocks, those of coarse material are
heaped up usuall}' and thin out rapidl}' in all directions, wdiile those
of line material have a greater area. This is true of superimposed
beds forming a group; when material is fine, the disappearance of
a bed is gradual. This law of area and thickness means only that
fine materials were spread over a larger area '" in conse(|ucnce of
their comparatively light specific gravity, or at least of their being
more easil}- and therefore more widely transported by water, and
being more generally dift'used through it before finally coming to rest
at the bottom. It was pointed out before, too, that beds of coal so
far from forming any exception to this general rule, are its most
marked example at the one extreme, while coarse sandstones and
conglomerates form the most striking example at the other. . . .
I wish merely to sa}' as the result of an experience of a good many
years, confirmed by the particular instance under examination, that
the phenomena of the lamination and stratification of beds of coal,
and their interstratification and association with other stratified rocks
are explicable solely by the relation of the specific gravity of their
materials to the action of moving water, and the consecjuent diffu-
sion of their materials through the mass of that water."

The materials of the clays and sandstones were most largely
deposited on the northern side of the coal field and sometimes
failed to reach the southern part of the area, whereas the coal beds
''were diff'used e(|uall}', or at least more ecjually, over the whole
area." lie finds in the llottom coal l)ed a notable illustration of
these condition.^ — and it is only one of many. One '"cannot fail
to be struck with the i)bvious ' delta-like ' or ' bank-like ' form which
the Coal Measures of South Straft'ordshire must liave originally
possessed, and the perfect resemblance they must have had to an
undisturbed subaqueous accumulation. It seems to me then impos-
sible to suppose otherwise than that the whole series of the Coal

36

19II-] STEVEXSOX— FORMATION OF COAL BEDS. 37

Measures, coals included, were deposited by one connected operation
of the same forces acting in obedience to the same physical laws on
similar but slightly differing materials, through an indefinite but
immensely long period of time."

Dawson spent many years in investigation of the Acadian coal
fields, but devoted his attention especially to the South Joggins
region where exposures are almost complete in a section of more
than ii.ooo feet thickness. He visited that locality with Lyell in
1852 and 1853 and afterwards made detailed study of each coal bed
as well as of each ancient soil, subjecting samples from all to careful
macroscopic and microscopic examination. The results of his
studies were given in several memoirs and the details were pub-
lished in the second edition of " Acadian Geology." In his first
elaborate memoir'*^ he called attention to the gradual passage from
coal to the roof shales through laminae composed of coaled leaves
and flattened trunks, separated by clay. He expresses the opinion
that erect forests explain to some extent the accumulation in situ.
The sandstone casts of Sigillaricc are enclosed in bark converted
into caking bituminous coal, while remains of the woody matter
remain as mineral charcoal at the bottom of the cast. A series of
such stumps with flattened bark and prostrate trunks may consti-
tute a rudimentary bed of coal, of which many occur in the South
Joggins section. He is convinced that the structure of the coal
accords with the view that it accumulated by growth and not by
driftage and that accumulation was very slow. He regards Sigil-
laria and Calaiiiitcs as the chief contributors to the formation of
coal. The woody matter remains mostly as mineral charcoal, while
the cortex and such other portions as were submerged gave the
compact coal. This memoir is concerned, for the most part, with
the origin of coal.

In a later memoir,''- he considered especially the subject of accu-
mulation. After describing the formations and the physical condi-

" J. \\'. Dawson. " On the Vegetable Structures in Coal,"' O. J. G. S.,
Vol. XV., 1859. pp. 638. 640.

^' '■ On Conditions of the Deposition of Coal, more Especially as Illus-
trated by the Coal Formations of Nova Scotia and New Brunswick," Q. J.
G. S., Vol. XXII., 1866, pp. 95-104.

37

38 STEVENSON— FORAIATION OF COAL BEDS. [April 21.

lions observed in the numerous coal beds, he presents these con-
clusions :

( I ) The occurrence of Stigmaria under nearly every bed of coal
proves accumulation /;/ situ; the sediments between the beds prove
transport of mud and other materials, the conditions being those
observed in swampy deltas. (2) True coal consists mostly of bark
of Sigillarid and other trees, leaves of ferns and Cordiates with
other debris, fragments of mineral charcoal, all grown and accu-
mulated where they are found. (3) Microscopic structure and
chemical composition of cannel and earthy bitumen as well as of the
more highly bituminous and carbonaceous shales prove that they
were fine vegetable mud as in the ponds and lakes of modern swamps.
(4) A few undcrclays consist of this vegetable mud, but most of
them are bleached by drainage. They contain not sulphide but car-
bonate of iron; rain, not seawater, percolated through them. (5)
Most of the erect and prostrate trees had become hollow shells of
bark before final cmljedding and their wood had been broken into
cubical pieces of mineral charcoal ; land snails, galley worms and
reptiles were caught in them. There is much mineral charcoal on
surfaces in all the larger coal beds. (6) Sigillaria roots have much
resemblance to rhizomas of certain aquatic plants, but structurally
are identical with cycad roots, which the stems resemble. SigillaricB
grew on soils supporting conifers, Lcpidodciidra, Cordaitcs and
ferns, which could not grow in water. There is remarkable absence
of aquatic vegetation. (7) The occurrence of marine or brackish
water forms is no evidence of sub-aqueous formation. The same
condition is observed in the case of submerged forests.

The channels, sand or gravel ridges, ine(jualities of floor observed
in coal beds are familiar features of modern swamps. The lamina-
tion of coal is not aqueous lamination ; it is the superposition of suc-
cessive generations of more or less decayed trunks and beds of
leaves. It is very dififerent from the lamination observed in cannels
and in the carbonaceous shales.

The doctrine that coal is composed of the debris of land plants,
though maintained by nearly all students, did not pass unchallenged.
As far back as 181 5, Parrott suggested that seaweeds had contrib-

38

I9II-] STEVEXSOX— FORMATION OF COAL BEDS. 39

uted materially to the formation of coal and, at a later date, Bischofif
conceived that the Sargasso sea might yield a coal bed. Mohr/^
in 1866, presented this view with great energ>-, and his opinions
received more or less support from some eminent students.

Mohr contrasts stone- and browncoal. the one being fusible the
other infusible. Land plants with much woody fiber yield charcoal,
which soon decays when exposed to air and moisture. But sea-
weeds, river and lake algse, having no fiber, decay to slime, which
hardens through loss of COo and CH^ the original composition being
that of starch and the allied substances. He combats Bischoff's
assertion that Calamites and other land plants were concerned in
forming coal, for the mass of the coal is amorphous and no treat-
ment gives trace of plant skeleton. Evidently, everything with rec-
ognizable structure is a foreign body. Coal did not originate from
land plants but from water plants, whose growth is protected from
air and decay.

Only one of these water plants, a grass of wide distribution, is
a phaenerogam ; the genera and species of the others are very numer-
ous and their mass is inconceivable. The Sargasso sea alone has
an area seven times as great as that of Germany and none of its
material can escape. Here is ample material ; contributions from
land plants are only accessory. The ash from sea weeds contains
no clay ; that from coal, lignite and peat consists of silicates not
belonging to plants and contains clay. This material is derived
from land detritus. The ammonia in distillates from coal is of
animal origin ; no accumulations in landlocked basins could have
animals enough to supply this ammonia, but Darwin and Meyen
have described the vast numbers of mollusks and other forms
attached to seaweeds.

Sea plants are swept away, decay and sink or are distributed by
currents. They are heaped up to great thickness, there being 338
feet of coal in the Saarbruck basin. Darwin saw immense masses
of seaweed, floating, so constant in position that they are mapped
as reefs and sand banks. If a layer of leaf coal occur, it is evi-
dence only of material brought in from the land. The absence of

^¥. Mohr, " Geschichte der Erde," Bonn, 1866, pp. 82-icx), 130, 137.

39

40 STEVENSON— FORMATION OF COAL BEDS. [April 21.

animal remains in stone coal is due to the solvent power of carbon
dioxide coming from the decomposing seaweeds.

IVIuck'*'* came strongly to support of Mohr's doctrine in the first
edition of his work. The essential objections to the theory are:
(i) That great accumulations of seaweed are not likely to reach
the bottom; (2) that remains of seaweeds have not been found in
dredgings, which bring up only inorganic materials and animal
remains; (3) the poverty of earthy materials in stone coal; (4) the
absence of sea plants, and (5) the rare occurrence of sea shells in
stone coal.

The answers to these objections are:

That the first is based on supposition, originating in lack of
knowledge ; that, for the second, it may be well to wait for its invali-
dation by opposing facts ; as for the third, it stands in close connec-
tion with the second and so may be of narrowly conclusive value,
but it is to be remarked that the ash-poor glance coal alternates with
the often very ash-rich matt- and cannel coal, whose ash does not
proceed from beds intervening between the coals, but is so intimately
mixed with the coal stuff that it can be due in only small degree to
later infiltration ; as for the fourth, absence of sea plants is explained
by the fact that those plants, in dead or torn condition, with or
without access of air, undergo decay very quickly, becoming, within
a few weeks or months, a structureless mass, in which organic
remains cannot be recognized; the fifth is answered very easily, for
animal remains are calcareous and are removed by carbon dioxide
which originates during the coal making process.

In the second edition of his work. Muck, though no longer urging
the theory, argued that sea plants, embraced under the trivial term
" Tang," oft"ered and do off'er enough material for stone coal forma-
tion. The disappearance of organic structure in stone coal is ex-
plained as easily for seaweeds as for land plants by a kind of peaty
fermentation. The morphological differences between seaweeds and
the land plants corresponds to chemical differences in composition.

Petzholdf' gave a more than halting adhesion to this doctrine

"' F". Muck, "Die Cheinie der Steinkolile," Leipzig, ist cd., 1880: 2d ed.,
1891. The citations are from the second edition, pp. 162-165, 168.

" .'\. Petzholdt, " Beitrag zur Kenntniss der Steinkohlenbildung," Leipzig,
1882, pp. 25, 26, 27.

40

I9II.] STEVENSON— FORMATION OF COAL BEDS. 41

though without mentioning Mohr in connection with it. Referring
to the current opinion that the material for formation of coal may be
wholly or at least in great part derived from land plants, he says
that this is evidently pure hypothesis, for remains of undoubted
land plants occur in coal only under exceptional conditions. As, at
the time when stone coal and anthracite were formed, the land was
sunken, it is doubtful if the then production of land plants could
yield the vast quantit}' required for the coal beds, he is led to look
elsewhere for suitable material — and that, the sea plants appear to
have produced. Remembering that the fauna of the Coal ^Measure
time was marine and that, for these vast numbers of genera and
species, the nourishment could come only from algse, he asks with
Bischoff, " where are the remains of the vast masses of sea plants,
which since the Plant Kingdom first appeared on earth, have grown
and then perished?" He replies that they have been consumed in
forming coal and anthracite beds ; and he is compelled to admit the
conclusion that algse, not land plants, produced the chief material for
coal-making. At the same time, he is careful to state that this is only
hypothesis, without direct proof, since remains of algse are as rare in
coal as are those of land plants.

Mietzsch*^' devoted much space to discussion of this hypothesis.
which he regarded as baseless. His objections are those tabulated by
]\Iuck in the work just cited. In the concluding part of his argu-
ment, he points out that the Challenger expedition crossed the ocean
along several lines and that the results of dredging leave uncertain
whether seaweeds, after death, reach the bottom, become decomposed
at the surface or become covered with animal remains. The Chal-
lenger expedition found no seaweed on the way to coal, though,
several times it crossed the area, where, if ever, such deposits might
be expected. Not only the petrography of coal but also the palseon-
tology opposes the hypothesis. Seaweeds have not been discovered
and the forms known in earlier days as fucoids have proved to be
land plants.

Lesquereux"*' referred to ]\Iohr"s hypothesis only to reject it.

■"^ H. Mietzsch, " Geologic der Kohlenlager," Leipzig, 1875, p. 244.
" L. Lesquereux, Ann. Rep. 2d Geo!. Survey of Penn. for 1885, p. 104.
Same for 1886, p. 465.

41

42 STEVENSON— FORMATION OF COAL BEDS. [April 21.

Seaweeds have cellular structure alone. They decompose cjuickly
whether exposed to atmospheric oxygen or protected from it. They
are soon transformed into a fluid, black material which penetrates
the sands along the seashore. He thinks it possible that remains of
marine algas may have been thrown casually on swamps and that
their decomposition products, added to those of the decomposing
materials, may have enriched them and may have given cannel.

J. Geikie** sees in the alternation of coal and limestone, evidence
of prevailing subsidence, while the coal seams indicate frequent re-
currence of land surfaces. The cannel's and iron-stones show that
many wide lakes and lagoons existed. He finds lines and ribs of
cannel associated with splint and even ordinary coals, while the can-
nel itself passes into common coal or black shale or even into black-
band ironstone. The varying conditions are due to the mode of accu-
mulation. Cannel was formed under water, for it contains fresh or
brackish water fossils. The expanse of fresh water was surrounded
by wooded flats; slimy vegetable mud, with, in places, ferruginous
matter, was deposited where the streams entered. Along the shores
were marsh plants, while farther back were trees and fern under-
growth. The last gave ordinary coal, the marshy plants were con-
verted into splint, while the slime became cannel, oil-shale or even
iron-stone.

Stevenson,^^ as the result of studies in the Upper Coal Measures
(Monongahela) of Ohio and West Virginia, came to the conclusion
that at the close of the Lower Barren Measures (Conemaugh) the
northern part of the Appalachian area basin was a half-filled trough
separated from the western coal areas by the Cincinnati fold. He
accepted the in situ doctrine without reserve. The conditions ob-
served in the Upper Coal Measures prove a succession of gradual
subsidences interrupted by intervals of repose, during each of which
a lid of coal was formed over all or part of the basin. The sub-
sidence could not have been paroxysmal, for, as the shore line sank,

^''J. Gcikie, "On the Geological Features of the Coal and Iron-stone-
bearing Strata of the West of Scotland," Jonrn. Iron and Steel Inst.. Vol.
III., 1872, pp. 13, 14.

^■■'J. J. Stevenson, " Tlie Upper Coal Measures West of the Alleghany
Mountains," Ann. Lye. Nat. Hist., N. Y., Vol. X., 1873, pp. 226-252.

42

191 1-] STEVENSON— FORMATION OF COAL BEDS. 43

the great marsh, which became the Pittsburg coal bed, crept up the
shore — and this perhaps to the very close of the epoch. Thus it is,
that though giving origin to many subordinate seams, the great bed
diminishes westward. The Pittsburg coal bed began at the east
and advanced westwardly. There is evidence in the distribution of
sandstones and shales that a delta formation at the east pushed out
into the basin, so that conditions favorable to coal-making existed
first on the east side of the great basin. His summary is :

( I ) The great bituminous trough west from the Alleghanies does
not owe its basin-shape primarily to the Appalachian revolution.
(2) The coal measures of this basin were not united to those of
Indiana and Illinois at any time posterior to the Lower Coal Meas-
ures (Allegheny) and probably were always distinct. (3) The
Upper Coal Measures (Alonongahela) extended as far west as the
Muskingum river in Ohio. (4) Throughout the Upper Coal ]\Ieas-
ures epoch, the general condition was that of subsidence, interrupted
by longer or shorter intervals of repose. During subsidence, the
Pittsburgh marsh crept up the shore, and in each of the longer
intervals of repose it pushed out upon the advancing land, thus giving
rise to the successive beds of the Upper Coal Measures. (5) The
Pittsburgh marsh had its origin at the east.

Two years later,"*" after further studies in West \'irginia, he
ofifered additional arguments in favor of his suggestions and ex-
tended the scope of his hypothesis. The Appalachian basin at the
beginning of the Upper Coal Pleasures was closely landlocked, com-
municating with the ocean at the southwest by a comparatively nar-
row outlet. At the east and southeast, rivers brought in their loads
of detritus to be spread over the bottom of the basin ; on the opposite
side, few and sluggish streams flowed from the low Cincinnati fold.
During periods of repose, deltas were formed and the marsh ad-
vanced on the newly formed land. If the period of repose were long
enough to permit the filling of the bay. the marsh would extend
across if begun on one side, or to the middle if passing out from all
sides. The basin in West Virginia was never so filled with detritus
as to permit coal beds to cross it. The Appalachian basin was never

'""On the Alleged Parallelism of Coal Beds," Proc. Aiiici: Phil. Soc,
Vol. XIV., 1875, pp. 283-295.

43

44 STEVENSON— FORMATION OF COAL BEDS. [April 21.

united with those at the west, anywhere north from Kentucky and
he leaves to others to decide if tlicre was at any time a connection
farther south.

Still later/'' after very detailed studies in southwest Pennsylvania,
he discussed the question Are coal heds continuous? He describes
the Pittsburgh, Waynesburgh, Waynesburgh A and Washington coal
beds as practically continuous in the northern portion of the Appa-
lachian basin within Ohio, Pennsylvania and West Virginia — that is
to say. that they are almost invarial)ly present wherever their horizon
is reached. P»ut that is not true of the intermediate beds, wdiich fre-
quently are wanting in considerable areas ; yet they are constant in
many great spaces of from 100 to i.ooo scjuare miles: he cannot
resist the conviction that these beds are not in isolated patches but
that for the most part these apparently separate areas are merely
parts of a connected whole. The barren spaces mark localities which
did not present conditions favorable to accumulation of coal. Res-
pecting coal beds older than those of the Upper Coal Measures, he
is convinced by the evidence of borings, that all. with possible excep-
tion of two, merely fringed the border of the basin.

Andrews,'" in rendering the final report upon his work in south-
eastern Ohio, presented the conclusions respecting formation of coal
to which he had been led by his many years study of the Ohio
measures.

The Lower Carboniferous detrital rocks were deposited in shallow
water; the sandstones show ripple marks, striae and branches of
marine plants (the indefinite Sf^iropliyto)i ) . Some conglomerate
appears in the early part of the Coal Measures, but it is confined to
the shore side of the basin and disappears eastwardly [toward the
center of the basin]. Rocks exhibit ra])id variations laterally; sand-
stones pass into shales ; limestones into shales and sandstones. Some
marine limestones, formed in shallow' water, indicate, as do the coal
beds, pauses in the almost continuous subsidence ; but the great lime-
stones of the Upper Measures [Monongahela] are to be considered
merely as calcareous muds, for they vary as do the other mud rocks.

"2(1 Geol. Surv. Penn. Rep. KKK. ITarrisburg, 1878, pp. 283-295, 301-303.
"E. B. Andrews. Geol. Survey of Ohio, Vol. I., Part I., Columbus, 1873,

PP- 345. .347-351. 354, 357. 358.

44

I9H.] STEVEXSOX— FORMATIOX OF COAL BEDS. 45

They were deposited in shallow water, for they are close to coal beds
and show the shrinkage cracks due to drying.

Andrews adheres to the doctrine of accumulation /;/ situ, assert-
ing that his studies leave no room for any other conclusion. The
vegetation grew on marshy plains skirting the ocean or perhaps
making low islands near the shore. Slates as coal partings are of
great geographical extent, holding the same stratigraphical position
throughout, thus implying a temporary overflow of the marsh by
ocean waters, with an even distribution of the sediment. Some beds
contain evidence of tidal flows, for beachworn sticks, replaced by
pyrite, lie in the coal as they were drifted upon the marsh. After
complete submergence of the bog, trees growing on the surface were
overthrown by turbulent waters ; thousands of trunks of Pccoptcris
arborcsccns are seen in the roof of the Pomeroy coal bed, bent or
broken down by the sediment-carrying water ; and with them are
great trunks of Sigillaria and Lcf^idodciidroii : while, in sandstone,
drifted and buried trees from upland areas are not rare. The con-
tinuity of coal seams was often interrupted, as should be expected in
great areas.

Andrews's studies were confined chiefly to southeastern Ohio and
the adjacent portions of West A'irginia, where the coal area ap-
proaches the central part of the basin, the original western border
having been many miles beyond the present western limit of the Coal
?\Ieasures. The irregularities of deposit are comparativelv insigni-
ficant and the important members show a remarkable parallelism.
He was led by the phenomena of his region to deny the possibility of
notable variations in thickness of intervals between coal beds and he
refused to accept as correct the great variations reported from the
anthracite areas.

There are many evidences of erosion and planation during deposi-
tion of sandstones. The great bed on Sunday creek shows erosion
from one foot to entire thickness of the bed, the overlying sandstone
filling the trench and resting unconformably on the eroded edges of
the coal. The eroded surface is smooth, there being no traces of
rough work such as one should expect to find, if the coal were still
soft and unconsolidated at the time of removal.

45

46 STEVENSON— FORMATION OF COAL BEDS. [April 21.

Andrews thought that cannel was originally vegetable mud. He
emphasizes the abundance of Stigniaria, saying that they fairly
reveled in this ooze. They, with their rootlets, abound throughout ;
their existence in these beds for hundreds of miles almost necessitates
the conclusion that they are /// situ. If they are roots of Sigillaria,
those trees must have grown in the wettest portions of the marsh,
wdiich, in that case, could not have been lagoons. The Stigniaria are
evenly distributed. If they had been drifted in, he thinks they ought
to have gone to nmck with the rest.

Newberry,""' in the following year, discussed the origin of the
various deposits composing the Coal Measures. The coarse rock
underlving the series contains rounded pebbles of quartz, igneous
and metamorphic rocks, with rounded and angular sand of the same
material as well as cherty pebbles from the Lower Carboniferous.
The pebbles for the most part must have come from Archean areas
at the east and north : but he finds difficulty in explaining how ma-
terial from those areas could be distributed in sheets at hundreds of
miles from the only possible sources of supply. It is difficult to con-
ceive of rivers as the transporting agency and he is inclined to find
the explanation in the drift deposits of the Mississippi valley, ice
being the transporting agent. Where the rock is coarse, fragments
of the tree trunks, of Calauiifcs and of roots are present, all broken,
and sometimes heaped in masses covering several rods. Fruits, like
Trigonocarpitiii, occur in hollow calamites and the mass is like
driftwood, everything broken and battered.

The fireclays sometimes contain stumps of Sigillaria and Lcpido-
dcndron in unbroken connection with Stigniaria roots. Coal is
seldom wanting above fireclay, though at times it has been removed
bv erosion. Coal beds were formed in situ. Fine sediment accumu-
lated in pools and these were invaded by vegetable growth, to be
filled up finall\- by bitumenized remains of generations of plants.
Aquatic plants remove alkalies, phosphorus, sulphur and silica from
the soils, as is seen in peat bogs, where the imderclays are often
fireclavs. The varxing deposits are explained l\v alternate eleva-
tions and depressions of the surface. Limestones were formed in
arms of the sea and their presence is proof of imequal subsidence.

■''^J. S. XevvlKTi-y, Geo). Survc\- of Ohio, Vol. II., part I., Columbus. 1874,
pp. 1 04- 1 1 5. 118.

46

I9I1.] STEVEXSOX— FORMATION OF COAL BEDS. 47

Newberrv opposed the doctrine that spores of cryptogamous
plants are important constituents of coal. Sporangia and spores
are common enough in American coals but they are an inconsiderable
part of the whole.

Dana,^* reasoning from chemical analyses, objected to Dawson's
suggestion that coal was derived largely from bark or material of
that nature. Though nearer coal in composition than is true wood,
bark resists alteration longer and is less easily converted into coal.
The occurrence of stumps and stems outside of the coal beds, " while
proof that the interior wood of the plants was loose in texture and
very easily decayed, is no evidence that those trees contributed only
their cortical portion to the beds of vegetable debris. Moreover,
the cortical part of Lepidodendrids (under which group the Sigil-
larids are included by the best authorities) and of Ferns also, is
made of the bases of the fallen leaves, and is not like ordinary bark
in constitution ; and Eqniscta: have nothing that even looks like bark.
This cortical part was the firmest part of the wood ; and for this
reason it could continue to stand after the interior had decayed away
— an event hardly possible in the case of a bark-covered conifer, how-
ever decomposable the wood might be. Further, trunks of conifers
are often found in the later geological formations, changed tlirough-
oiit the interior completely to Brown coal or lignite.'" He appears to
be convinced that the whole plant material contributed to formation
of the coal, which he regards as the product of marsh accumulation.

Dawson'^' returned to the discussion in view of Huxley's asser-
tion that spores are an important constituent of the coal-forming
mass. Referring to his study of more than eighty coal beds in Nova
Scotia and Cape Breton, he asserts that the trunks of SigiUaria and
similar trees constitute the great part of the densest portion of the
coal and that cortical tissues, rather than wood, predominate.
Spores and spore cases, though often present abundantly, constitute
only an infinitesimal part of the great coal beds. Sporangites or
bodies resembling them are present in most coals, but they are acci-

" J. D. Dana, '"Manual of Geology,"' 2d ed.. X'ew York, 1874, pp. .361,
362. 366.

"J. W. Dawson. Amcr. Jauni. Sci., 1874. Supplement to 2d ed. of
" Acadian Geology," 1878, pp. 65.

47

48 STEVENSON— FORMATION OF COAL BEDS. [April 21.

dental rather than essential constituents, more likely to be found in
cannel and shales, deposited in ponds near lycopod forests, than
in the swampy or peaty deposits, whence the coal beds proceed.
While giving credit to Huxley and his predecessors for calling atten-
tion to the importance of spores in coal, he is compelled to maintain
that they have generalized on insufficient basis, that sporangitic beds
are exceptional among coals and that cortical and woody matters
are most abundant. The purest layers of coal are composed of
flattened trunks; other coals are made up of finely comminuted par-
ticles, mostly epidermal tissues — not only from fruits and spore
cases but also from leaves and stems.

Mietzsch^''"^ attempted to answer the question, how did the vege-
table material accumulate in great beds? Was it brought down by
rivers from forest covered areas or did the plants grow where the
coal is now found? The mode of occurrence can be explained
measurably by either supposition ; at times one pr(Kess may act alone,
at time it may be j^ermissible to regard both as contributing.

He describes the heaping up of driftwood along streams as well
as on coasts, whither it has been carried by currents ; and he thinks
that in this way may have originated some tertiar\- deposits of
lignite, composed almost wholly of stems stripped of their bark.
But many deposits of lignite and brown coal contain stems with
bark, twigs, leaves and fruit preserved. The Suterbrander lignite
of Iceland was formerly sujjposed to be driftwood, because of the
present conditions in that land ; but Heer discovered well-preserved
buds, leaves and twigs of the plants, represented by the stems, which
still retain their bark. The same criterion must be applied to the
black coals. Many deposits of these and the greater number of
brown coals have numerous tokens, rendering improbable, in part
impossible, the supposition that tliey were made of transported plant
masses. It is difficult to understand tlie regularity and vast extent
of coal beds on the theory of transport, for driftwood accumulations
are irregular and of small superficial extent.

The composition of coal tells against the theory of transport, for
in most beds the ash is very small — surprisingly small, for in the
process of coalification no ])art of the mineral content of the nlants

"^H. Mictzscb, "Geologic (kr KoliIciilaRcr." Leii)zis, 1875, iip. ^44-2^7.

48

I9II.] STEVENSON— FOR^IATIOX OF COAL BEDS. 49

disappears, aside from soluble alkaline compounds. Some have
found proof of transport in the composition of ash from stone coal,
since it is quite similar to clay shale. But Mietzsch points out that
living Lycopodiacccc contain from 22 to 26 per cent, of clayey earth
in the ash and asks why one should suppose that the older types were
dififerent. But if the coal contain an abnormal proportion of ash,
there is reason to recognize influx of fine mud.

The fineness of the materials, clay and sand, in contact with the
coal, proves a long period of quiet ; and the same may be said of
the plant deposits themselves. Such a period can hardly be ac-
cepted for rivers or for currents along coasts. The conditions of
the underclay ; the resemblance of the clay in many cases, as Stefifens
showed, to vegetable mould; the interlacing of Stigmaria roots like
wicker work; and the occurrence of erect trunks are all opposed
to the doctrine of transport. In most cases the conditions can be
explained only by the doctrine that coal beds owe their origin to
plants which grew where their remains are now found. He accepts
the peat bog theory as advanced by v. Beroldingen and presents
many facts as additional evidence in its support. The advance of
bogs into lakes is proved by the discovery of pile constructions in
Swiss peat bogs ; along the seashore, algae form dense floating felts
on which bog plants grow and the mass sinks to the bottom. Zee-
land was once cut by ba}s much longer than now and part of the
former sea-area is filled with peat. He strengthens his argument by
many references to phenomena observed in the great swamps of
Europe and North America.

In order to explain the origin of coal-bearing strata, holding a
number of coal beds, one must distinguish between those formed
along a coast and those formed along rivers or in the interior of an
island or continent. Those of the first type are explained by the
subsidence of coasts bordering on the North Sea. The preliminary
work for drainage of the Zuyder Zee, as well as similar work else-
where, has proved the existence of peat bogs in extended areas of
shallow sea ; anchor flukes have brought up peat from depths of 200
meters on the English coast. Such bogs become covered by river
sediments and in case of long-continued slow sinking, the shallow
sea area is filled, so that a number of bogs may be formed suc-

PROC. .-MVIER. PHIL. SOC, L, IQSD, PRINTED APRIL 24, IQII.

49

50 STEVENSON— FORMATION OF COAL BEDS. [April 21.

cessively. Among other illustrations, he refers to the discovery at
Rotterdam of two bogs, 5 and 6 meters thick, separated by 4 meters
of clay; to the presence of erect trees which, despite the long period
which has passed since they sank below the water surface, are still
standing on the sea bottom, partly surrounded by sediments ; such
trees on the coast of the islands of Sylt and Romo are of types which
disappeared from that region many hundreds of years ago.

Changes in grade of rivers, caused by damming or by crustal
movements, would lead to covering of bogs with sand or mud and
to the accumulation of rock masses. He finds confirmation of this
view in Livingstone's statements respecting the floods of African
rivers and in the observations of others elsewhere.

Lesley'^' in prefaces to reports by geologists of the Pennsylvania
survey, made frequent references to hypotheses respecting formation
of coal beds. Ordinarily, he preferred to present the matter, as it
were judicially, giving the difiiculties in the way of accepting the
hypotheses and leaving the decision to the reader. lUit in two of
the prefaces he offers some important suggestions.

W. G. Piatt described a little basin, barely a mile and a half
across, in which three sections of Coal bed D were obtained. In
all of them, the bottom bench is 2 feet 7 inches thick and composed
of brilliant coal ; but the upper part is a dull cannel or cannel shale,
measuring i foot 3 inches, 8 feet 3 inches and i foot 2 inches, while
between the last two the dip is about 8 degrees compared with about
one degree elsewhere. A noteworthy feature is that while the ash
in the cannel is from 21 to 25 per cent, and that in the pure coal
below is only 1.6 per cent., yet the ratio of volatile matter to fixed
carbon is practically the same throughout.

Lesley felt convinced that the petty basins, in which cannel was
deposited, were waterways or pools and that more of them existed
at once in certain horizons than in dthcrs. They were not due to
erosion for the underlying coal bed is not cut out, it is merely de-
pressed. There is no evidence of currents, for the mud is fine, the
lamination perfect and the roof soft. The pools were almost stag-
nant. How could a depression come about to give, as here, a dip

" J. P. Lesley, Second Geol. Survey of Pennsylvania, Indiana County,
1878, pp. xiv-xviii ; Lawrence County, pp. xix-xx.

50

19".] STEVEXSOX— FOR.MATIOX OF COAL BEDS. 51

of 5 to lo degrees to an almost dead level bituminous coal bed?
There is no room for suggestion of crustal movement as the area is
too small ; equally the cavern theory is excluded for no limestone
underlies the horizon except at vast depth. He can see no explana-
tion for most of the localities except in the subsidence of a floating
bog, such as Lesquereux has described. On this the fine muds ac-
cumulated and the pool was filled.

He was led in this connection to consider the sequence of coal
beds. If the Carboniferous plain consisted of a low area with
shallow ponds, the coal forming vegetation would conform to the
dimpled surface and there would be but one coal bed, intersected by
river channels. This plain, if continuous, would be not less than
i.ooo miles long by 300 miles wide [this refers to the Appalachian
basin]. It is very difficult to account for the submergence of this
continental plain to a depth of 50 feet below sealevel in order to give
opportunity for formation of a second bed. Yet this " slow de-
pression theory " may not be rejected easily, for without it, one
cannot conceive how^ 20,000 to 40,000 feet of palaeozoic sediments
could have been deposited ; the more so, since many of the strata
give every evidence of deposition in very shallow water. As a
partial alternati-ve. he suggests that the relative sea level may have
been changed by the filling of basins. The efi^ect of deposits by
great rivers and that of glaciation are discussed but no conclusion
is reached.

In the preface to the Lawrence report, he attempts to explain the
origin of underclays. A peat bog and even a lake invaded by
sphagnous growth must have some water circulation due to percola-
tion from the surrounding land and to evaporation from its own sur-
face— but the movement would be very feeble and it could transfer
only the finest mud. though in course of time the result would be
important. Dry grounds are largely fine gravel with rounded quartz
and feldspar grains ; the feldspar is soluble, it follows the indraught
and settles beneath the evaporating surface with its floating peat.
If the peat area be surrounded by clayey land, the percolation would
be at a minimum ; the water supply would be from the surface
and less muddy, so that the underclay would be less in quantity. It
would appear, then, that when the margin was a tight clay, deposits

51

52 STEVENSON— FORMATION OF COAL BEDS. lApdizi.

of calcareous type show that Hmestone must have been exposed
within the drainage area.

The thickest underclays should belong to beds next or near
above the great sandrocks and it is a fact that our great clay beds
are near the base of the Lower Productive Coal Measures [Alle-
gheny] and that the few important clay deposits high in the series
have coarse grained sandrocks not far below them. A logical con-
sequence of such conditions is that sandrocks geologically close to
such great underclays should be purer, more open sands and gravels
than others which had not been robbed of so large quantity of
interstitial clay. If the surrounding land contained iron in its
gravel, there should be ball ore in the fireclay — as is seen in the New
England ponds surrounded by drift.

Davis^'^ described a cannel deposit in Yorkshire, somewhat resem-
bling that discussed by Lesley. The bed is thickest in the center
and thins away in each direction, meantime becoming less pure and
passing into bituminous shale at the circumference. The condition
is due to in-floating of plant remains, which sank to the bottom of
the pond. The marked interlamination of shales and their marked
increase toward the border resulted from more rapid subsidence of
the muds. In some places the pond was filled up ; there the under-
clay has abundance of Stigmaria and the plants growing in such
places were converted into ordinary coal. Afterwards the whole
mass was submerged and covered with black mud. The cannel is
fine, close-grained, homogeneous, with conchoidal fracture, without
planes of deposition and everywhere yields beautiful specimens of
fishes.

Reinsch''^-' undertook the microscopic study of coal. He pre-
pared a great number of sections, subjected them to close examina-
tion and published his results in an elaborate volume with 95 plates.
These exhibited the structure of the coal as well as numerous forms
which seemed to be organized. Reinsch maintained that the coal

^*J. W. Davis, "On the Fish Remains found in the Cannel Coal of the
Middle Coal Measures of the West Riding of Yorkshire," Q. J. G. S., Vol.
XXXVI., 1880, p. 56.

'-^ P. F. Reinsch, " Ncuc Untersuchungen uher die Mikrostructur dcr
Steinkohle des Carbon, der Dyas nnd Trias," Leipzig. 1881.

52

i9:i.] STEVENSON— FORMATION OF COAL BEDS. 53

substance originated, mainly, from marine plants of such peculiar
form that they cannot be assigned to any group of known types.
He created a new group for their reception, Protophytce, of which
he made seven divisions. Remains of land plants are of very rare
occurrence. This hypothesis diiTers from that of Mohr in that the
plants are microscopic.

Petzholdt°° at once made a fierce critique of Reinsch himself,
his methods and his results. Of the seven divisions of Protophytce
two are decomposition products, three are certainly inorganic, one
consists of fragments of land plants and one is based on minute
fragments of coal. The decomposition products, mistaken for
organic bodies, are termed bitumen by Petzholdt, who thinks them
the same with those discovered fifty years before by Hutton in his
study of the Newcastle coals.

Fischer and Rust,-'^ following Reinsch's method, found not only
yellow and reddish resin-like bodies in black coal, such as make up
the great part of the Scotch boghead, but also small grains, showing
wood structure, in anthracite. In the black coal, they observed
spindle-shaped or serpent-shaped bodies, whose relations they could
not determine. The English cannel from Lancashire is very rich
in little resinous cylinders and, as far as richness in resinous matter
is concerned, is intermediate between the Bogheads and the ordinary
coals. These studies have an important bearing on investigations
which have attracted much attention in more recent years.

Green"- says that it is not easy to see how light material, such
as dead wood, could be spread out evenly over tracts of hundreds
of square miles, so evenly that the deposit shows comparatively little
variation in thickness ; and it is equally difficult to understand how,
in case the coal be composed of drifted materials, it could be so
pure as we often find it. The water bringing the vegetable matter

""A. Petzholdt, " Beitrag zur Kenntniss der Steinkohlenbildung," Leip-
zig, 1882, pp. 23 et seq.

"' H. Fischer and D. Rust, " Ueber d. mikroskopische Verhalten verschie-
dener Kohlenwasserstoffe, Harze und Kohlen," Croth Zcitschrift f. Kryst.,
Vol. VIL, pp. 209-243. This has not been seen by the writer. Cited by
Petzholdt and v. Giimbel.

'-A. H. Green, "Geology," Part L, Physical Geology. London, 1882, pp.
257-262.

53

54 STEVENSON— FORMATION OF COAL BEDS. [April 21.

would certainly carry also mineral matter. The coal and its ash
may, both of them, be of vegetable origin. Logan's discovery of
the underclay or Seatstone under nearly every coal bed was the first
great step in the right direction toward solving the problem. Bin-
ney's study of an erect stump discovered by Hawkshaw near Man-
chester was the next, for there a Sigillaria with Stigmaria roots was
rooted in a seat clay, while the stem was surrounded by rock. Many
similar cases were discovered. The underclay was the old soil sup-
porting plants which produced a layer of nearly pure vegetable
matter. When the surface was lowered beneath the water, sand
and clay were laid on top and the band of dead plants was converted
by pressure and chemical change into a seam of coal.

When sinking ceased, the shallow water was filled up and a
swampy plain was made. \'egetation spread out from the land and
a second coal bed began to accumulate. This process repeated many
times over gave a succession of sandstone and shale with coal beds
at intervals. The great swampy expanses in the delta of the Ganges
and Brahmapootra must bear close resemblance to the marshy flats
in which the coal was formed. The nearest approach, however, is
in the accumulations on the coast of Patagonia, described by Lady
Brassey in " A Voyage in the Sunbeam " ; " To penetrate far inland
was not easy owing to the denseness of the vegetation. Large trees
had fallen and, rotting where they lay, had become the birthplace of
thousands of other trees, shrubs, plants, mosses and lichens. In
fact in some places, we might almost be said to be walking on tops
of the trees, and first one and then another of the party found his
feet slipping through into unknown depths."

There are, however, deposits of subacjueous coal, derived from
driftwood carried cjown and buried amid mechanical deposits, but
they are irregular and are apt to be impure. It is probable that the
patches of canncl coal mark sites of pools or lakes in which vege-
table matter lay until it was maceratefl into a \n\\\). This passes
gradually by increase of earthy admixture into well-stratified carbo-
naceous shale.

Green had already presented the same suggestions, though briefly,
in his work on the Yorkshire coal-field published in 1878.

54

I9II-] STEVENSON— FORMATION OF COAL BEDS. 55

Grand' Eury,"^ in the first section of his notable memoir, gives
the grounds on which his theory of transport is based.

When one makes minute examination of coal, he discovers that
the plants have been broken up and the parts scattered ; fruits and
leaves are apart from the stems ; the layers of the bark are sepa-
rated and dispersed ; the interior parts of the stems have disap-
peared and the flattened cortex alone remains. The woody portions
of the stems have been dispersed as fusain [mineral charcoal].
Stems are split and torn, Cordaitcs leaves are imperfect, everything,
bark or leaf, is broken up. He thinks that a great part of the tissues
was transformed into a kind of vegetable pulp, which makes up most
of certain coal beds. That this was not wholly fluid or homogeneous
is evident, for one may distinguish some traces of organization with
the microscope or even with a magnifying glass.

The disintegration cf the plant organs occurred after death and
its character puts aside all suggestion of violent action. All the
evidence contradicts the supposition that the forests were ravaged
by inundations ; everything points to quiet, peaceable flow of water.
Most of the material was decomposed in place and carried away
piecemeal. The vegetable matter was not deposited in deltas within
either the north or the center of France.

The preservation of stems reduced to their bark is not surprising,
for there was little wood in trees of the Carboniferous; but the min-
eral charcoal is not so easily accounted for. It seems to be fossilized
buried wood, dried in the air and not changed into coal. It did not
originate through maceration, though after formation it may have
been subjected to moisture, as is indicated by lack of sharpness in
outline.

The vegetable disaggregation was rapid, mostly in air, and was
completed in swamps before removal. The conversion into detritus
and the quasi-dissolution were sometimes pushed very far at the
base of damp forests and at the bottom of swamps. The Car-
boniferous forests were marshy and aquatic. The plants grew
quickly, reached maturity and soon died. Growth had to be ener-
getic in order to carbonize the bark so as to make the contraction

''■'G. Grand' Eury, " Memoire sur la formation de la houille," Ann. dcs
Mines., Ser. 8, T. i., Paris, 1882, pp. 101-122.

55

56 STEVENSON— FORMATION OF COAL BEDS. [April 21.

small in coalification. That the air was damp and warm is proved
by the aerial roots of Psaroiiiiis and Calaiiiodoidroii ; and the heat
of the climate appears from the dense resinous bark, which often
dominated the wood. Strong light, great heat, excessive humidity,
great marshes in which plants grew quickly and died, explain condi-
tions not easily explained by conditions of the present time. The
residues falling into the marshy bottom of the forest, underwent
aqueous rotting; they were then transported to the areas of deposit,
which preserved them from complete destruction.

Grand' Eury published much relating to this subject and in
I90O'''* he summarized all the results of his long studies in a memoir
presented to the geological congress.

He describes fossil forests /// situ, which show that the Car-
boniferous plants, though arborescent, were forms of marsh-habit
like those of the Dismal Swamp, the foot and adventive roots in
the water, but the stocks and rhizomas creeping on the bottom. The
forests were very local. Growing in stagnant water and fixed by
few roots to the ground, they were destroyed by slight causes and
the roots alone remained. This would give a "soil of vegetation"
as described by Dawson— a feature as familiar at Saint-Etienne as
in Canada.

Coal is stratified, evidently deposited under water. There is no
evidence that roots ever traversed the parallel laminse of which it
is composed. The stocks and roots, descending in the roof, spread
out on the coal but never penetrated it. This condition is constant
and is due to the circumstance that slowly deposited vegetable mat-
ter, undergoing fermentation, is opposed to the introduction of roots,
which, being unable to live in it, instinctively refuse to pierce it.
Similarly there is no relation between stocks and overlying coal.
Their roots are often enclosed in coarse twisted coal composed of
overturned stems, with leaves, branches, which, however, is con-
tinuous with overlying laminated coal. The elements are the same
in both and they are identical with those in the adjacent shales, so
that transportation from a distance is impossible. There is then in
some coal beds evidence of formation in place or almost in place.

■"'C. Grand" Eury, "Du liassin de la Loire," Coiiipt. Rcndiis I'llI'""
Congrcs Gcul. Intern., Paris, 1901, pp. 521-538.

56

I9II.] STEVEXSOX— FORMATIOX OF COAL BEDS. 57

But most of the material forming the beds was transported ;
yet all coals resemble that found almost in place and the parts, cer-
tainly transported, are identical with similar parts of the rooted
stems. The materials were derived from marshy forests on borders
of the basin, which doubtless succeeded those temporarily installed
in the basin of the deposit which afterwards became a lake. At the
foot of this forest was elaborated, as in peat bogs, the humus or
fundamental material of the coal. The basin of deposit was much
like the bottom of a morass, for the mud of coal beds often resem-
bles the clay underlying peat bogs. The debris of plants falling
into water on the borders of the marsh became stratified in its
depths. Grand' Eury was convinced that by this hypothesis he had
reconciled the opposing theories, for he has shown that certain coal
beds were formed by concurrence of both processes, as in the sub-
aquatic parts of some swamps.

The permanent swamps, where primitive peat was elaborated,
were not exposed to deposit of mineral sediments, they remained
uncovered and disappeared ; so that very little of the coal formed
in place remains. The researches of Renault and C. E. Bertrand
on cannel and the fundamental matter of coal show that coal was
not always deposited on lake bottoms under moving waters, but that
it may have been formed in stagnant or quiet waters of swamps.

The coal was deposited slowly, not continuously and there may
have been long periods of arrested growth. The concentration of
fossil forests and soils of vegetation in and near coal beds proves
for the thick beds a very long period. Additional evidence in this
direction is found in the advanced decomposition of the rocks form-
ing the roof, their new chemical combinations, their impregnation
with carbon, showing that they had been long in contact with the
swamp before being transported and deposited on the coal bed.

The basin of the Loire was subjected to orogenic movements.
The fossil forests have irregular distribution both vertically and
horizontally ; great sterile deposits break up the continuity. The
basin was deepening throughout the period of formation, but each
important coal bed corresponds to an interval of stability. That
the mineral materials were brought in by streams is shown by their

o7

58 STEVENSON— FORMATION OF COAL BEDS. [April 21.

(listrihiilion. The granitic rocks of the northern portion thin toward
the south and tlieir rooted stems lean toward the south and south-
east ; hut the micaceous rocks of the southern portion thin toward
the north and the rooted stems lean in the same direction, sometimes
strongly. These mineral deposits interlock as wedges. But the coal
heds pass from one type of rock to the other, preserving well their
distance and parallelism. Grand' Eury finds no evidence to support
the delta-theory of accumulation in deep hasins ; every feature leads
to the helief that the mass of rocks could accumulate only hy means
of a suhsidence, equal and progressive from the clay hottom.

In a still later paper, "^ Grand' Eury shows that coals of all kinds
are practically alike in origin.

Coal heds are deposits of allochthonous peats formed hy an
exuberant vegetation, loving water, whose detritus was carried from
shores to interior of immense marshy lagoons, where barks, cuticles
and the rest were stratified with ulmic substances under the water.
Stipites or dry coals of the Secondary in Erance are clearly the
same in origin with the coals. Mineral charcoal is so abundant in
one of the I'pper Cretaceous coals as to give a finely-stratified
structure to the bed. The brown coals of the Tertiary resemble coal
completely in mode of occurrence; they are composed of marsh
plants, leaves of dry land plants being in small proportion. Lignite
is wood-like in appearance though formed of red humus from plants ;
they show much variation, but the mass of the material is derived
from marsh forms. The peats of lowland areas or marshy plains
are allochthonous — they resemble almost all deposits of mineral coal.

Gruner*"' notes the ancient forest in the quarry of Treuil, which
had been described by Alex. l>rongniart many years before. At
100 meters lower and almost directly under the quarry, Gruner found
in the Treuil mine twelve great trunks in a space of less than lO
meters square ; their roots spread out over the coal but did not pene-
trate into it.

He cannot accept the doctrine that coal consists of transported
material. The continuity and uniformity of coal beds make a serious

"•'' C. Grand" I'.iiry. " Sur la fonuation dcs couclies dc liouille dc stipite,
dc brownkohle et de lignite," Autun, 1902, pp. 123-132.

""L. Gruner, " Bassin houiller de la Loire," Paris, 1882, pp. 160-170.

58

I9II.] STEVENSON— FORMATION OF COAL BEDS. 59

objection. In the little basins of Saint-Etienne, beds can be followed
5 to lo kilometers in one direction and 2 to 4 in another with little
change. He thinks that a current capable of uprooting trees would
tear away the soil and pebbles also, so as to give a mingling of trees
and detrital matter.

As large streams carry much mineral material there should be
an alternation of vegetable elements and mud — and this is found
in coal beds where shale appears in thin layers between benches
of coal. These shales or the nerfs of fine sandstone could be pro-
duced only by water-currents, by inundations of brief duration cov-
ering the debris on the surface or invading shallow basins in which
leaves, etc., were deposited slowly. The two modes of accumulation
went on simultaneously in the coal period as they do now in peat
bogs. He does not assert that coal was the peat of palaeozoic times;
the flora and the climate were difl^erent ; but the mode of formation
was the same. The plants of the coal epoch grew where their
remains are found. He cannot accept Grand' Eury's theory, which
opposes the doctrine of in situ accumulation because stumps and
trees are wanting in the coal beds themselves. Grand' Eury main-
tains that the vegetable matter was transferred from the place of
growth to the basin where the coal is found, but the distance was
small.

Gruner maintains that the current would have brought more than
leaves and stems and that it would have distributed its load unecjually ;
he thinks it preferable to conceive of a marshland extensive enough
to admit of a thick cover of vegetable debris over an area of several
thousands of square kilometers — as one finds in the Nord basin.
Grand' Eury emphasizes the absence of stumps and roots passing
from coal beds to the mur. But at Saint-Etienne itself, Lyell and
Gruner saw rootlets passing from the coal into the underclay and
Gruner saw the same condition in the Batardes coal bed, where
Stigmaria abounds in the mur. The absence of stumps in the coal
is to be expected, because the soft tissues would be crushed quickly
under pressure and all traces would be effaced ; moreover, in the
nature of the case, stumps would be only a small portion of the
mass. A negative result of study does not prove that the plants

59

60 STEVENSON— FORMATION OF COAL BEDS. [April 21.

did not grow sur place. Since the rapid current, which piled sand
around the forests of Treuil, did not uproot the trees, one finds
difficulty in understanding how the waters so slightly agitated as to
be able to draw off only leaves and twigs did not leave in place the
stumps whose roots are seen to-day in the underclays.

The preservation of the underclay proves that the stumps were
not torn out before deposit of the plant debris forming the coal bed.
The clay shows no signs of erosive action such as are seen so often
in the roof. The deposit of the clay is itself a proof that then had
begun the long period of tranquillity, which continued during forma-
tion of the coal. He is convinced that it must be admitted as almost
proved that the coal beds have come from a vigorous local vegeta-
tion, whose debris accumulated at the bottom of shallow stagnant
water and probably, quite as often, on a damp but not flooded
surface.

The intervening rocks are, in character, wholly similar to part-
ings in the coal beds, but they were formed not by petty inundations
but by strong currents of prolonged duration. The existence of
these is proved by erosions as well as by the sands which covered
the coal forests. The surface subsided at intervals, as shown by
phenomena connected with the faults in the Loire basin. But the
flora was not destroyed, for one finds forests or isolated trees in
place, in sandstones at all horizons, their bark preserved as coal.
The sands are evidence that the agitated water prevented quiet depo-
sition of vegetable debris. That was destroyed or scattered afar.

Meanwhile, the sunken surface was leveled up and the depres-
sion was filled. A second marsh was formed above the first, now
buried under a thick bed of sand or mud. If the deposit of sand,
etc., did not exceed 30 meters, the conditions under which the new
bed was formed might not differ from those of the earlier bed. But
when the sterile interval attains great thickness, 100 to 800 meters,
the period of depression was very long and before its close the flora
had undergone modification. Thus it is that one finds successive
appearance of varied types, so that classification of the Coal ]\Ieas-
ures by their flora becomes possible. Subsidence of the type here
conceived has been observed in rocks of all epochs. Lament and

I9II.] STEVENSON— FORMATION OF COAL BEDS. 61

Degousie, in sinking artesian wells at Venice, found beds of lignite
and carbonaceous clays at 40, 60, 100 and 120 meters from the
surface.

\'on Giimbel,''' perplexed by the contradictory results presented
in memoirs, undertook a series of systematic studies, covering all
phases of the subject. His study did not concern itself with chem-
ical or technical matters and had little reference to botanical rela-
tions. At the outset, it deals only with questions relating to the
constitution of coals; it begins with examination of peat-like sub-
stances and advances, step by step, to anthracite and graphite ; it
ends with a discussion of the mode in which coal beds accumulated.
In breadth of scope, this study excelled that by any predecessor ; in
compactness and precision of statement the memoir has rarely been
excelled. Much of the earlier portions bear directly on questions
respecting the transformation of vegetable matter into coal, a sub-
ject to be considered in a later part of this work; but some of his
observations are so closely connected with the final part of his dis-
cussion that they cannot be neglected.

The method of investigation by means of thin sections did not
commend itself to v. Giimbel, who preferred the method proposed
by Franz Schultze. The broken coal was treated first with potas-
sium chlorate and strong nitric acid, and afterward with ammonia,
in order to separate the particles and to make the transparent por-
tions more readily available. Absolute alcohol completed the prepa-
ration by removing coloring matters. He gives specific directions
as to the use of the reagents and warns against the possibilities of
error in the study.

This investigation led him to recognize that the whole series from
peat to anthracite is continuous and of similar origin. All of the
members are made up of combustible materials. " Stone coal con-
sists, apart from the earthy admixtures, of parts of plants, which,
changed into a coaly substance, have taken up into their empty
spaces, as well as into the intervals between the plant debris, a
humin-like or ulmin-like substance ( carbohumin ) which was origi-

°' C. W. V. Gumbel, " Beitrage zur Kenntniss der Texturverhaltnisse dcr
Mineralkohlen," Sitcuiigs. Bcrichfcn dcr k. buyer. Akad. d. Wissenschaften.
Mafh.-Pliys. Klassc. 1883, pp. 113 et seq. The citations are from pp. igo-212.

61

62 STEVENSON— FORMATION OF COAL BEDS. [April 21.

nally soluble, but became insoluble, so tliat tbe whole is amorphous
and apparently structureless." The taking up of this material is the
Inkohlungsprozess.

Adjacent rocks, containing plant remains, may have contributed
to this coalification by means of circulating waters. It is self-
evident that this soluble material might be deposited by itself apart
from any remains of plants, not merely as layers of a coal bed but
also in cracks and fissures : but such layers of structureless coal
could have contributed in only subordinate manner to the formation
of coal beds.

The several types of coal, Glanz-. ATatt-, Faser-, Cannelkohle
and the rest cannot have originated under similar conditions. In
considering these he takes the most complicated condition — where
several varieties occur in the same bed. Three modes of explana-
tion are suggested by the investigations : ( 1 ) Original diiTerences in
kinds and parts of plants; (2) differing conditions, chemical and
mechanical, in which the plants came to contribute toward making
the coal; (3) heterogeneous external conditions under which the
transformation was completed.

Difference in material in the several types of coal appeared con-
stantly during the study ; bark, and woody parts along with leaves
in Glanzkohle ; abundance of leaf organs, especially of the epidermis
layers and less abundance of hard parts in Mattkohle; constant
recurrence of little balls, membranes, the spores of authors, in aston-
ishing abundance with algae-like clumps in cannel-like layers; all
proving a certain dej)endence of constitution on the character of
the plant remains. It is clear that the condition under which the
{)lant material was accumulated was of great importance. This is
evident from the great amount of b'aserkohle | fusain, mineral char-
coal]. If this material result from decay in free air, as would occur
in the occasional (lr\ing of the surface in peat l)ogs, one must con-
cede that this process was of vast extent during the coal-making
time. It is unnecessary to sup]:)ose that the great supply was swept
in ; it could have been produced as readily on the bog surface. Simi-
larly the dismembered parts of plants, clods or flocks, and the rest
belong to a stadium anterior to formation of the coal. The pres-

62

191 1.] STEVEXSOX— FORMATION OF COAL BEDS. 63

ence of plant remains in soil, in every peat bog, justifies us in
tracing back in some degree, certain relations of coal formation to
similar origin. Accumulation of cannel-like coaly substances can-
not be explained otherwise. The tertiary gas coal of Falkenau,
pyropissite and Lebertorf all consist of a similar wholly broken up
mass of plant parts. External relations had much to do with the
conditiens. If inflowing water bring much mineral matter into a
bog, the borders are impure while the main portion is pure. So a
coal may be impure on the borders and pure in deeper portions of the
basin. Even the character of the overlying rock may be important.

Passing from the composition of the coals, he considers the mode
of accumulation; first of all. rejecting absolutely as without founda-
tion, the doctrine that coal could have been formed in the open sea
and from seaweeds.

Coal beds consist of alternating, mostly very thin layers, like
beds of sedimentary matter ; this, with the fact that they are asso-
ciated in series with undoubted sediments, seems to afiford proof
for the opinion that coal beds originate as do other sedimentary
strata, in contradiction of the so-called peat theory, which accepts
the idea of an origin in place after the manner of peat bogs. If
one confine his attention solely to this layer-like accumulation and
make no further inquiry, the conditions appear so completely ex-
plained bv the former doctrine that facts favoring the latter have
no value. \'. Gumbel thinks that the presence of upright stems is
of comparatively little importance as a proof of autochthonous
origin, since their presence is exceptional and it can be explained
in. several ways — by drifting, by advance of waters into swamp
forests or by plant growths floating on the water.

A careful examination of the query as to whether or not the
lamination of coal can be explained by anything except deposit of
suspended matter, leads to surprising results, when extended to the
newer coal accumulations. The Quaternary brown coal ofi^ers an
instructive illustration of the mode in which the lamination origi-
nated. These have absolutely the same structure as that of stone
coal beds. It is known positively that they owe their origin to peat-
like swamps and that the clayey, sandy partings, which accompany

63

64 STEVENSON— FORMATION OF COAL BEDS. [April 21.

them, proceeded from occasional overflows. Coming down a step
farther to the coal making of our own time and ignoring for the
present the various local modifications of peat, one can recognize
two distinct modifications ; Autochthonous, that forming or originat-
ing in place, and Allochthonous, the sedimentary, due to deposit of
plant detritus in pent up waters. The latter shows, of course, evi-
dence of sedimentary origin, is more or less dense and homogeneous,
contains much earthy matter and the plant remains are notably
advanced in change. Often it shows lamination only on drying.

All kinds of peat have the lamination. In Moortorf there are
often alternating layers, dififering in color, density and composition ;
in Specktorf the structure is especially distinct. Peat then is not
an unstratified mass and one cannot say that the lamination of coal
places it out of comparison with peat. Close investigation shows
so many similarities between the peat layers and those of some coals,
that this kind of structure favors rather than opposes comparison
of coal-making with peat-making. This lamination appears in the
autochthonous peat, in the diluvial brown coal originating in peat
and in the whole range of the brown coal formation. But one must
remember that the coals were not all formed on the same model ;
that comparison with peat is only tentative, as modern peat is made
from moss and swamp grasses, while in the coal time the deposits
came from a wholly difi^erent moor and swamp vegetation.

The stone coal formation for the most part is to be regarded
as an inland formation, originating in widespread leveling and sub-
siding of the land, in many cases on swampy lowland along the sea-
coast, over which floods distributed materials, such as shale and
sandstone. On the extensive but not high land of the Carboniferous
time, waters were penned in great areas and became converted into
morasses, where a luxuriant vegetation flourished. It is very prob-
able that in occasional drying of the swamp followed by renewal of
the flooding, one may find explanation of the alternating bright and
dull coal. This does not exclude influ.x of broken and shattered
plant stuff from the higher surrounding region ; that might even
have predominated in some localities and have been the basis for
cannel and boghead. Even from llic swamp vegetation itself, decay-

64

19II-] STEVENSON— FORMATIOX OF COAL BEDS. 65

ing material might tioat away to deep water within the swamp, so
as to be heaped into pecuHar massive layers like cannel. Flooding of
the plain and deposit of mineral matter checked formation of coal;
but the swamp would be re-established and a second formation be
made ; or possibly for a long period only rock material might be
deposited.

How far variation in the water niveau may atiect the question
is considered only so far by v. Giimbel as to let him warn against
the conception that basins, now filled by a thick series of coal
bearing deposits, were filled with water in like manner at the be-
ginning. These bowls were filled very gradually ; they must be
thought of as filled temporarily by a relatively shallow pond of
water, which little by little reached a higher level.

At times, marine remains occur in strata between the coal beds,
a condition which seems opposed to the explanation offered. But
this occurrence is due to the fact that the low swamp land was
spread out near the sea and was exposed to invasions, so that remains
of marine animals might be enclosed in materials originating on the
land. ^Marine or brackish water forms might be enclosed in the coal
deposit itself, if it were formed alongside an arm of the sea.

In general, coal beds are an autochthonous product of dead,
broken and disintegrated plant fragments with only local and petty
contribution of transported material of the same character.

A\'ethered*'^ called attention to the fact that coal seams are not
single beds, but are separated by partings into benches which may
dift'er in quality as well as structure. Sometimes Stigmaria are
present in the partings.

The Cannock Chase or Shallow seam, near Edinburgh, has in its
upper bench, i foot lo inches thick, the brownish layers composed
of macrospores and microspores, while the bright layers, containing
some woodv tissue, are composed mostly of a structureless material
which he terms " hydrocarbon " in preference to " bitumen."
Whence this comes he does not know, but wood tissue may con-
tribute to it. The middle division of the bed is very different,
consisting almost whollv of *' hydrocarbon " with very few spores,

* E. Wethered. " On the Structure and Formation of Coal," Q. J. G. S.,
Vol. XL, 1884, Proceed., pp. 59, 60.

PROG. AMER. PHIL. SOC, L. I98 E, PRINTED APRIL 25 I9II.

65

66 STEVENSON— FORMATION OF COAL BEDS. [April 21.

It is possible that spores may have been there and that they may
have been decomposed, but spores are much more resistant than
is woody materiah The main division has a great accumulation of
spores but also a fair proportion of the " hydrocarbon." He con-
cludes that some coals are made up practically of spores, others are
not; the differences in benches of a coal bed are of this character.
Harker, reasoning from the ornamentation of the spores, suggested
that they may have come from a plant related somewhat to Isoetus.

In the discussion of this paper, Carruthers took exception to con-
clusions based on markings seen on spores. He knew of no reason
for referring those spores to Isoetus or any other form of sub-
meged vegetation. Spores in coal were discovered first by Morris ;
they are associated with Sigillaria and Lepidodendron; the coal was
the soil for the vegetation, penetrated by Stigniaria roots of the
plants. A Sigillaria stem, at the Leeds museum, filled with white
sand, penetrated far into the coal in which it grew. Coal seams are
remains of forests which grew on swampy ground. The macro-
spores were not composed originally of brown substance, they are
merely filled with it.

E. T. Newton stated that some coals are certainly made up of
macrospores and microspores. Dull coal contains spotted tissue ; in-
termediate coal contains both forms of spores ; bright coal is a
brown substance, usually structureless, but in one case, known to
him, it consists wholly of spores.

Dawkins had never found sporangia in coal though both macro-
spores and microspores arc abundant. Coal consists of carbon and
resin, the latter giving the property of blazing, which Huxley would
attribute chiefly to the spores. With this conclusion, Dawkins
agrees only in part. The carbon comes from decomposition of
woody portions, but the resin from cell concretions in the living
plant. Carboniferous forests grew on level alluvial tracts but little
above the water level.

Dawkins,"^ discussing the geographical conditions in Great Britain

during Carboniferous time described the mode in which the coal beds

accumulated.

""W. B. Dawkins, "On the Geography of Britain in the Carboniferous
Period," Trans. Manchester Gcol Soc, Vol XIX., 1887, pp. 45-47.

66

I9II-] STEVENSON— FORMATION OF COAL BEDS. 67

Oscillations of level still continued as the north, but the land
constantly encroached on the shallowing sea, the mud encroaching
on the Carboniferous liinestone and the sandbanks following the
mud closely. ^Meanwhile " the terrestrial vegetation was spreading
from the old Lower Carboniferous land areas over the new Upper
Carboniferous marsh lands, from the mountains of Wales and
from the other Lower Carboniferous islands, now uplands. These
forests contributed in their decay, through many generations, the
accumulation which now, compacted by pressure and subjected to
earth heat, is familiar to us as a coal seam. Each coal seam repre-
sents a land surface, just as the sandbanks and mudbanks (sand-
stones and shales) above it point to submergence. The fact too
that the coal seams in a given section are parallel to each other or
nearly so, implies that the forests grew on horizontal tracts of land,
just as the associated sandbanks and mudbanks, with marine or
freshwater shells, prove that these horizontal tracts were near the
sea level or within reach of the waters of a mighty river. We may
learn also from the study of the isolated coal fields that this great
horizontal tract of forest clad alluvia occupied nearly the whole
area of the British isles in the Upper Carboniferous age, from the
Scotch Highlands southward, the dead flat being broken only by the
higher lands, the old islands of the Lower Carboniferous sea, which
I have already described. It was indeed the delta of a mighty river,
analogous in every particular to that of the Mississippi — a delta in
which from time to time the forest growths became depressed beneath
the water until the whole thickness (7,200 feet in Lancashire) was
accumulated of coal seams and associated sandstones and shales.
After each depression the forest spread again over the bare expanse
of sand and mud piled up in the depression."

The great northern and western land, termed by Dawkins,
Archaia, whence came this mass of mineral deposits, occupied the
North Atlantic sea, stretching from the west coast of Ireland and
the Scottish Highlands to the American continent. To this great
land may be traced the pebbles and groups of pebbles found in the
Lancashire coal seams, mostly quartzites, which probably were
brought down in flood time in roots of trees from the shingle beach.

67

08 STEVENSON— FORMATION OF COAL BEDS. [April 21.

Williamson,'" in discussing the characteristics of the great fossil
in the Owens college museum, remarked that that specimen had
removed finally all doubts respecting the relations of Stigmaria by
showing that plant to be the root of Sigillaria. The roots divide
only once and after division extend indefinitely. The stigmata are
lacking near the stem because the roots increased by exogenous
growth and the superficial portion with its rootlets was thrown ofif.
The trees grew in swampy ground as the swamp cypress does in
American swamps. The gymnospermous plants grew on drier
ground. The particular tree under consideration must have been
at least 100 feet high. When it died, decay continued downward to
the point shown and then was checked probably because the lower
portion was buried in sediment and protected from air. Thence
decay proceeded very slowly until the woody tissue of even the root
disappeared. Meanwhile, the surrounding rock had hardened and
had taken a cast of the stem and roots. The surface sank beneath
the water and soft sand filled the cavity; thus the roots have their
original form.

Fayol, after si)ending man}' years in study of the basin of Com-
mentry, published his results in a remarkable work, which is un-
excelled as a record of detailed observation. This work presented
the grounds on which, several years before, its author had based bis
theory respecting the formation of coal beds. The positive posi-
tion taken in favor of the transport theory and the clearness, with
which the observations were ofi:'ered, caused a notable reaction in
favor of the doctrine that coal beds are formed of transported vege-
table matter. A year after publication of the work, Fayol gave a
summary of the delta theory, as he termed it, at the summer meeting
of the Geological Society, when several members of the society com-
mented on the theory. This resume, being the later presentation, is
the basis of the present svno])sis.''

The theory is based on the laws of sedimentation, as observed in

'"W. C. Williain.soii, "On the Fossil Trees of the Coal Measures,"
Trims. Manchester Gcol. Soc.. Vol. XIX., 1888, pp. 381-387.

" II. F'ayol, " fitndes siir Ic terrain liouillc dc Commentry," F". partie.
" Lithologic et stratigrai)hie." lUiU. Soc. M in. Ind. St-Etiennc, 2'"" Ser.,
XV., Liv., III., IV., 1RS7; "Resume de la theorie des deltas et histoire du
bassin dc Coninuntry," IhdI. Geol. Sue. France, 3"" Ser., XVI., pp. 968-978.

(58

I9II.] STEVENSON— FORMATION OF COAL BEDS. 69

deltas. ]\Iingled detritus brought in by streams forms a stratified
deposit in the basin, where the beds may be composed of a single
substance or of several. Those beds are inclined, irregular and
of small extent in tranquil waters but less inclined and of wider
extent in agitated water. The inclination may vary from o to 45
degrees ; different portions of a bed may vary much in age, while
beds at different levels may be contemporaneous. The total thick-
ness of a deposit has no necessary relation to the sum of thicknesses
of the beds which compose it, for a basin, 100 meters deep, may be
filled with inclined beds which may have a total thickness of 1,000
meters ; he gives illustrations of these conditions.

The little basin of Ccmmentry is one of several isolated areas in
a synclinal which is about 60 kilometers long. These are separated
by granite and gneiss and the evidence shows that they were always
separate. That of Commentry, 9 by 3 kilometers, contains only Car-
boniferous rocks, except at the northwest, where some Permian re-
mains. The rocks are not disposed at hazard, but there are definite
zones or areas, each with its own type of rock, and these areas, as
it were, interlock laterally. Each contains detritus derived from a
single locality, though there is a greater or less intermingling where
the deposits interlock as overlapping wedges. The history of the
basin is thus interpreted by Fayol.

A lake, 9 by 3 kilometers in area and 800 meters deep, was sur-
rounded by steep mountains. Rainwater ate away the surface,
digged valleys, carried to the lake pebbles, sands, clay and plant
materials, by which at length the lake was filled. This was one of
numerous lakes, depressions and alpine elevations on the central
plateau of France. Sediment brought in by the streams was heaped
up at mouths and formed deltas. The main stream at the northwest,
the Bourrus, cut through the mica schist and reached the granite, the
latter being found in the upper part of the delta. This delta has the
steep slope, with pebbles, blocks, sand, clay and plant debris, all dis-
posed in accord with the laws of delta deposit. A somewhat smaller
stream, the Colombier, at the east, flowing over anthracitiferous beds
and afterwards cutting back to crystalline rocks, formed another
delta of similar ty])e ; while petty streams from the north formed

69

70 STEVENSON— FORMATION OF COAL BEDS. [April 21.

small intermediate deltas. Apparently nothing came from the south,
where the waters found their outlet. As the deltas increased in size
and approached each other, their elements intermingled.

The lighter materials, clay and plant, floated into a bay in the
southeast corner, where they formed some beds of shale and coal,
while in less degree, similar materials floated off on the other side of
the Bourrus delta into the bay at the west, where, in like manner,
deposits of shale and coal accumulated. Eventually the Bourrus
delta divided the lake into two small ponds and in the larger were
formed thin irregular lenticular beds of impure coal. At length the
lake was filled up and streams began to destroy the coal formation.
Disturbances set in afterward but they were not serious, for the
Permian deposits are almost horizontal.

The facts to support this explanation of the origin of the beds,
both mineral and vegetable, are presented abundantly in the great
excavations. The walls show local faultings, thinning of faisceaux
of beds, pebbles of coal are seen in several strata, a great lenticular
parting, in part very coarsely conglomerate, occurs in the Grande
Couche. This remarkable coal bed is only a few centimeters thick at
the southeast outcrop, but it swells thence to 10 to 12 meters and
retains that thickness along the outcrop for about 2 kilometers and a
half, beyond which it becomes thinner and at length disappears. Fol-
lowed down the dip, it decreases in thickness and disappears toward
the depth of 350 meters. The outcrop resembles an open C and the
interval from the outcrop to the old rock is 500 to 800 meters.
Before disappearing at the west, the bed breaks up into six diverging
branches. Two other beds, the Gres noirs and the Pourrats, are in
contact with the great bed at the southeast but they diverge west-
ward. Some lenticular deposits of anthracite occur at the base of the
series in both bays.

Fayol made careful calculation of the quantity of vegetation
which could be produced on the whole drainage area of the lake and
asserted that enough be produced to give ten times the coal present —
and this within the period of 17,000 years. This period is a maxi-
mum, corresponding to a very slow filling and to the minimum trans-
portation of vegetable material. On the hypothesis of formation in

70

I9II.] STEVENSON— FORMATION OF COAL BEDS. 71

sitit after the manner of swamps, he thinks a period of 800,000 years
would be required.

Fayol's delta theory, then, is that the deep lake was filled gradually
with material carried down by the streams ; that this material was
deposited according to its gravity, fine clay and vegetable matter
being regarded as equivalents ; the arrangement being that observed
in deltas. It differs from the theory offered by Jukes by adding the
suggestion of great original depth of the basin, a conception against
which V. Gumbel had argued a number of years before.

The record of the summer meeting of the Geological Society was
issued as a separate'- and it contains the discussions by several mem-
bers. The doctrine as enunciated by Fayol was regarded by Busquet
as applicable to the basin of Decize, by Nougarede as supported by
much observed in the basin of Epinac, and by Bergeron as explaining
the conditions observed at Grassesac and Decazeville.

Renevier'^ was not prepared to give assent to the doctrine and he
suggested some grounds for hesitation. Vegetable materials in sus-
pension are equivalent to fine mineral debris. If the coal beds were
formed, as Fayol thinks, by the sweeping ofT of vegetable debris from
the land and its deposition on the surface of the delta, that debris
should accumulate on the border of the dejection cone, in the more
tranquil waters, so that the deposit should have only a gentle original
slope. But the great bed of Commentry has an extreme dip of 50
degrees, the same with that of the beds which accompany it. He
regards these dips as impossible in a cone of dejection and suggests
other modes of accounting for them. He maintained that the phe-
nomena indicate, in part at least, the agency of marshy or semi-
aquatic vegetation. Even the great thickness of the Grande Couche
seems to him an argument in favor of vegetation in place, receiving
increment brought in from the neighboring forests.

Delafond'* was inclined to question the applicability of the
doctrine without modification to the basins of the Saone-et-Loire
(those of Autun, Blanzy and Creusot). Fayol conceived the exist-
ence, before the coal deposition, of a deep depression transformed

" " Reunion extraordinaire dans rAllier," Bull. Soc. Geol. dc France, 3"""
Ser., XVI., 1890.

" E. Renevier, " Reunion, etc.," pp. yy, 78.
"F. Delafond, "Reunion, etc.," pp. 73-78.

71

72 STEVENSON— FORMATION OF COAL BEDS. [April 21.

into a lake, in whicli would be deposited, in form of a delta, the vari-
ous elements which constitute the Coal Measures ; the plants, giving
the coal beds, would have been furnished principally by the luxuriant
forests which grew on the alluvial plains of the deltas. During and
after the formation of the Coal Measures, the movements of the
crust were so unimportant as to leave no apparent trace, so that to-
day one can easily find all the circumstances accompanying the for-
mation of the deposit. But these were not the conditions in either the
basin of Autun or in that of Blanzy and Creusot. There were
important movements of the crust during and after the Carbonifer-
ous and the Permian.

In Autun the successive stages overlap in such fashion as to be
explained only by admitting, during the process of deposition, the
existence of crustal movements which modified profoundly the shape
of the basin. Further, it would be difficult to explain by this doctrine
why in Autun the important coal beds are in only the lowest part
of the formation, at the time when the alluvial plains of the deltas
were small; wdiereas, in the later part of the formation when those
plains should have acquired great extent and could support immense
forests, there were formed only some insignificant deposits in the
Upper Coal Measures. Similarly in the other basins of the Saone-et-
Loire, there were movements during the formation of the Coal
Measures and of the Permian, which caused the overlapping of
deposits.

Delafond recognizes that the process of delta formation explains
the manner of deposit, the separation of the various materials, coal,
shale, sandstone; but the intervention of movements of the crust is
indispensable.

De Launay '•'' remarked that it would not be incompatible with the
theory of deltas to believe that movements of the crust occurred
during the period of the Coal Measures and that they had given
progressively the great depth observed to-day.

Almost at once after the appearance of Fayol's first publication,
de Lai)parent'" gave his adhesion to the new doctrine. His first

" L. De Launay, "Reunion, etc.," p. 102, footnote.

'"A. de Lapparent, " L'Origine de la liouillc," Assoc. Franc. Avanc.
Science. Conferences de Paris, 1892. The same in Rev. dcs quest, scien-
iifiqucs, Juillct, 1892.

72

19"] STEVEXSOX— FORMATION OF COAL BEDS. 73

publication was in 1887; in 1892 he presented his views in vigorous
fashion. The statements are made with that clearness and precision
which characterized his writings, so that it is well to give the synopsis
in detail.

The early observers regarded coal as due to transported vegetable
materials but the fascination of actual conditions, as exposed by
Lyell, led men to abandon that explanation and to see in the vast peat
bogs of this day the modern representative of coal beds. De Lappa-
rent gives a synoptical statement of the peat bog theory. He thinks
this doctrine deserving of a double reproach — it draws no argument
from the nature of the coal itself" and it does not consider suffic-
iently the topographical conditions of each bed.

De Lapparent says that coal, especially in the great maritime
basins, has wholly mineral aspect, laminated, with conchoidal fract-
ure and showing no sign of organization ; even thin sections show
only amorphous material with rare indications of cellular structure.
In most cases, chemical and microscopical examination must be com-
bined, but sometimes the former is unnecessary. Fayol discovered at
Commentry, in 1883, lenticular brilliant zones which proved to be
flattened stems. Grand' Eury, in 1876, asserted that the coal of the
Loire basin was formed of vegetable remains laid flat in a position
uniform enough to suggest a liquid in repose. Several beds at Saint-
Etienne consist wholly of Cordaites bark and the Grande Couche at
Decazeville is composed of bark of Calmnodcndron. This determina-
tion, first made by Grand' Eury, is interesting as showing that the
leaves, barks, etc., play in the coal the same part that vegetable im-
prints do in the shale. The ulmic matter, resulting from maceration
of vegetable detritus, formed the sediment in which the recognizable
remains were buried.

To explain the origin of this amorphous material, he cjuotes
Saporta, who relates graphically the conditions existing in the dense
forests of the hot, humid Carboniferous time. The rapidly accumu-
lating mass of leaves, loose internal material from tree trunks, was

" It is well to remark in passing that de Lapparent's statement was made
54 years after Link's investigations, 2<3 years after Dawson's publications in
the Q. J. G. S. and 9 years after publication of v. Giimbel's elaborate
researches.

73

74 STEVENSON— FORMATION OF COAL BEDS. [April 21.

converted into ulmic material, the lower part of the deposit becoming
a blackish paste. Detached heaps of leaves, peripheral sheaths of
ferns, cortex of Sicjillaria, Cordaitcs, etc., obstructed places at foot
of slopes and awaited only the passage of waters in order to abandon
to them the great mass of material in various stages of decomposi-
tion. This vegetable pulp is the amorphous gangue in which one
finds the barks and leaves. But it is no longer in place. It shows
evidence of having been suspended in water; the condition of the
fragments shows that they have been subjected to frequent and
energetic friction. By what mechanism was this transport effected?

Grand' Eury thought that the waters of great rains sweeping
down the slopes drew the vegetable detritus into lagoons — such
waters were limpid. At other times the streams carried muddy
water with sand and clay giving sandstone and shale. Thus was
explained the alternation of coal with other rocks. But de Lapparent
cannot understand this selective process — the conditions are unlike
those of the present day. The delta theory of Fayol is preferable
and it applies perfectly to the lacustrian basins of central France.
It is no mere hypothesis, but the result of long, painstaking observa-
tion in the great open quarries of Commentry. More, Fayol made
experiments which proved that the conditions were such as must be
due to delta formation.

The cause was gained and it remained only to answer objections
offered by adherents to the old theory. The presence of vertical
trunks was shown to be not only not inconsistent but rather consistent
with the theory. And this was the most important objection. The
presence of Stigmaria in the underclay is no objection. Those are
rhizomas capable of giving origin to Sigillaria : when swept by tor-
rential currents, they were drawn into the deltas, where being heavier
they would pass to the bottom of the mass which was to become coal.
The delta theory is full of important consequences. There is no
further need of numerous and complicated movements of the crust.
The beds have Ijeen deposited one on the other as sediments on the
surface of a submerged dejection cone. If complete stability of the
surface be one of the conditions of the phenomenon, there is at least
no a priori reason to ])ut it in doulit ; as the beds had to be deposited

74

191 1.] STEVENSON— FORMATION OF COAL BEDS. 75

with a certain inclination, there is no need of calHng in, for lake
basins, dislocations to explain phenomena which may very well be
primordial. The time required for the deposits is vastly shortened.
Not only a complete coal bed, whatever its thickness, but also a por-
tion of the underlying clay and sandstone, becomes before our eyes
the product of a single flood. Fayol has shown also the rapidity with
which vegetable matter is transformed into coal. The coal of pebbles
in the rocks is coal, so that when a portion of the delta was exposed
by a change in equilibrium of the surface, its coal sufi^ered erosion as
did the other rocks. De Lapparent finds in the study of Commentry
some important matters bearing on the origin of the coal itself, which
will be considered in another connection.

The coal of the maritime basins of France is a vegetable allu-
vium deposited in a delta ; but the material has been brought from
a greater distance and by the action of the waves it has been
spread out over a greater area. In the central plateau the vegetable
paquets descended violently from the neighboring steep slopes to
be deposited en bloc with pebbles of the torrent, thus producing some
thick but very localized masses of coal. In the Nord area, there
must have been, far above the mouth, wide river sheets in time
of flood, many kilometers broad, like the Amazon and Orinoco, on
whose surface the vegetable matter was spread. In subsiding, the
ulmic materials, which formed the chief mass, separated themselves
from the fine clays. This explains the constancy of the floor, while
the roof may consist of any materral. As the uniuacerated vegetable
matters, fronds and barks, had to float on the surface of the ulmic
materials, one can understand why they are so abundant in the
roof. The mouth of rivers changed their position, which explains
the invasion of brackish waters. Thus is understood easily the
filling of the old arm of the sea.

Why is it that a theory, so luiuinous, has not gained the adhesion
of any but Frenchmen? De Lapparent thinks the hesitation due
to lack of confidence in anything novel which comes from outside,
and tends to overthrow notions so long accepted that thev seem
to be part of a national patrimony. Foreign doctrines are subjected
to quarantine as foreign goods at a custom house. It is possible that

75

76 STEVENSON— FORMATION OF COAL BEDS. [April 21.

the hesitation is due to imperfect exposition of the doctrine at the
outset, when Fayol dcchned to accept crustal movements as having
had any influence ; but that error was corrected afterward by Fayol.
De Lapparent considers that to deny all influence of orogenic move-
ments upon even the lacustrian areas would be excessive. Coal
basins are depressions, feeble lines of the earth's crust, are land-
marks of fractures whose equilibrium has been disturbed frequently.
Malherbe"* notes that, though the explicit statement is not made,
Fayol evidently regarded his doctrine as of universal application.
But Malherbe asserts that, while it may suffice for Commentry, it
cannot suffice for other basins. He utilizes the Liege basin as test-
ing ground. That basin has an area of 40 by 15 kilometers, with 50
coal beds and numerous petty scams. The northerly border is but
slightly disturbed ; away from that the disturbances become serious
and some of the faults extend through the formation, which is 1,200
to 1,500 meters thick. This is very different from Commentry,
which is small in surface and depth, enclosing an insignificant num-
ber of beds. If the Commentry strata arc in the original position,
those of the Liege basin must be the same ; but everything proves
the contrary — the enormous displacements of the beds, the presence
of Cardiiim in horizontal and inclined beds alike ; all show original
horizontal deposit. The waters from the Liege basin carry salt
and Roget-Laloy has proved the same for the coal formation of the
north of France, concluding therefrom that that is the sea water of
the coal time imprisoned in the rocks. The deposit is not lacustrian
but fluvio-marine.

Fayol's capital objection to theories other than his own is the
apparent impossibility of periodicity in deluges due to terrestrial
oscillations. Malherbe thinks it equally difficult to explain by
Fayol's hypothesis the transport of a mineral formation, 1.500 meters
thick and enclosing 50 coal beds from 0.45 meter upwards on an
area comparable with that of modern seas — ^for the elevations break-
ing the area into basins came after the coal time. Oscillations are
known in the present time, they are probable for other times. If
one recognize tliat subsidences necessary for formation of beds

" R. Mallicrbc, " Geologic de la houillc," Ann. Soc. Gcol. dc Bclgiquc.
T. XVII., 1890, ^ilcmoirs, pp. 25-40.

76

I9II-] STEVENSON— FORMATIOX OF COAL BEDS. 77

occurred onlv during accumulation of the great beds and that the
overflows, bringing about the deposition of sterile rocks, led to
transportation of vegetable matter intercalated in the intervals as
veinettes, the number of overflows would be greatly reduced. Mal-
herbe discusses Fayol's doctrine in detail and at the close expresses
much doubt respecting its competence to explain even the phenomena
of Commentr}'.

Renault'*' says that coal beds are intercalated among beds of
sandstone and shale and, like those, they have all the features of
deposits made in water. In sandstone, the fragments are inorganic
and preserve the chemical as well as the mineralogical characters
of the rocks whence they came ; in coal, they are derived from plants
and conserve the anatomical, at times, also the chemical characters
of the plant organs. The fragmentary condition of these organs,
the small proportion which they form of the mass, consisting chiefly
of a blackish vegetable powder as gangue, show that the plants
had been subjected to repeated energetic friction before their burial.
So one cannot admit that coal beds were formed solely by accumula-
tion, snr place, of debris from an exceptional vegetation, spreading
over marshes, lowlands, lagoons, etc., near lakes or the sea; that
the surface, subject to elevation and depression, saw, checked and
again restored, that great vegetation of which innumerable genera-
tions would be represented by successive coal beds.

The fragments of wood and bark are very small. If the vege-
table materials had been changed into coal and buried where their
debris is found, it is certain that, in place of these reduced frag-
ments, there would be entire trunks, branches and coiuplete leaves
as principal constituents of the mass. ]\Iore, taking into considera-
tion the diminution of volume, which vegetable tissues experienced
in becoming coal, it is evident that numerous forests of high trees
growing successively on the same place, would form hardly a few
centimeters of compact coal — even though one suppose that, at
the foot of the trees, there grew a mass of herbaceous plants.
Further, the thick coal beds are separated by great deposits of sand-
stone or shale ; as those deposits were fonued slowly after the
" B. Renault, " Etudes sur le terrain houiller de Commentry," Livr. 2'""
Flore fossile, Saint-Etienne, 1890, pp. 704-7T2.

77

78 STEVENSON— FORMATION OF COAL BEDS. [Apiil2i.

manner of sediments, one must assign, if he admit this succession,
an extraordinary duration to the coal epoch.

Renault accepts the explanation offered by Fayol and commends
especially the shortness of the time which it requires. During the
Carboniferous time, the air held more moisture than now, as no
ice cap covered the polar regions ; the rains were frequent and
abundant; depressions occupied by lakes were filled rapidly. If one
consider the strength of the torrents, greater than now, and the
vigorous growth of vegetation, surpassing that of the present tropical
regions, he will recognize that the formation in the Basin of Com-
mentary could have been deposited in even less time than is re-
quired by the Fayol hypothesis. The selection, so distinct in deposi-
tion in inorganic materials, would take place with equal readiness
in the plant materials. Coarse fragments, such as trunks, branches,
would be dropped with the sand and clays, while the lighter, finer
materials would be carried beyond into deeper parts of the basin.

Erect stems have little bearing upon the question at issue.
Many of them are merely in-floated fragments, while those, which
are in situ, do not penetrate the coal beds and have no relation to
them.

Spring*" undertook investigation along a new line. His study,
though bearing largely on the question of transformation, finds
place here because the results have an important bearing on the
manner of accumulation. The homogeneity, the structure and com-
position of coal beds all seem to favor the doctrine of transport ; but
the stratification within coal beds does not exclude the doctrine
of in situ origin, for with rare exceptions modern peat bogs show a
structure resembling that of coal. It is clear that a definite conclu-
sion respecting mode of formation cannot be reached by study of
the coal bed alone : he determined to investigate the shales of mur
and toit.

The mur of a bed formed by transpcM't would be impregnated with
vegetable matter to some distance below the coal while the toit
should contain little. In the Belgian terrane, the shales of the toit,

*** W. Spring, "Determination du carl)onc ct de I'hydrogene dans Ics
scliistes houillers," Ann. Soc. Geo!, dr Brhilqnc, XIV., 1888, " Memoire.s," pp.
131-154.

78

I9I1.] STEVENSON— FORMATION OF COAL BEDS. 79

when broken up by atmospheric agencies, yield a hard rather plastic
material, resisting plant growth, yet they are as black as those of
the mur. The theory of origin from peat would require that, in
the mur, the quantity of carbon increase as it approaches the coal,
as it must contain roots of plants ; while in the toit the carbon should
decrease gradually as one recedes from the coal. There is no
abrupt change from coal to shale in the roof, so that the latter should
be richer in carbon than the mur.

It is necessary to see how transformation of vegetable matter
into coal is explained by each theory. This necessity is felt by de-
fenders of the transport theory, because the flowing water furnishes
only a mass of wood, bark, leaves whereas according to the theory
of peat bog origin, the change of vegetable matter into peat is
associated with the deposition.

In passing from vegetable matter to coal, there is great loss in
hydrogen and great enrichment in carbon. Either the plant ma-
terials were changed into peat, lignite and the rest successively, or
the organic matter was converted at once into its present state with-
out passing through the intermediate stages. The latter explanation
rests chiefly on Fremy's experiments, which showed that vegetable
matter, subjected to high pressure and a temperature of 200° to
300° C. for a long time, becomes converted into a material very
closely resembling bituminous coal. A fundamental objection to
this theory is that no evidence exists suggesting that any such
temperature prevailed, and nothing is less established than -the con-
ception that time could compensate for deficiency in heat.

However this may be, it is evident that, according to the doctrine
of transport, the change going on in materials between the shales
requires that specimens of shale collected at equal distances in re-
ceding from the coal, should show the carbon and hydrogen varying
in a determinate manner ; in proportion as one recedes from the
coal the shale should have less of carbon and more of hydrogen
as the more volatile hydrocarbons would go farther. But the doc-
trine of peatbog origin leads to a contrary condition.

A determination of the carbon and hydrogen in shales near
coal beds may aid in answering the question as to whether the

79

80 STEVENSON— FORMATION OF COAL BEDS. [April 21.

hydrocarbons are impregnations from the forming coal or are due,
as in the coal itself, to transformation in place of vegetable debris,
imprisoned when the shales were deposited. These determinations
would tell us if one should prefer the doctrine of transport to that
of formation /;/ situ, and whether the transformation of vegetable
matter into coal has been accomplished by a kind of distillation or
has been caused by a special kind of fermentation.

In the course of his studies. Spring discovered an unexpected
condition — that the shales, containing organic matter, were the
seat of slow oxidation, depriving them of hydrogen. The shales
not only protected the coal from erosion but also from oxvgen, as
gas or in solution, the action of the oxygen being exhausted in the
shales. As the encasing rocks are not the same everywhere, the
character of the coal should differ in the same bed and in different
beds. Usually, meager coals are on the peripheral parts of a basin
while fat coals prevail in the middle portions. May this be be-
cause the latter have been better protected against the action of
ox\'gen ?

The .shale samples studied were from the Saint-Gilles mine near
Liege, eight of them, with one from the coal bed. Five were taken
from the toit and three from the mur, each representing a vertical
space of a half meter. They are marked "a," " b," " c," "d" and
"e" for the toit and i, 2 and 3 for the mur. The material was
dried and analyzed with these results ;

Coa'. "a" '• b " "c" "d" "e" 123

Car1)on 86.61 7.54 t,.t,^ 2.21 1.20 0.70 0.99 0.93 0.80

Hydrogen 4.65 0.79 0.62 0.54 0.56 0.59 0.84 0.53 0.58

Ash 1.84 98.33 92.05 93.86 92.00 94.08 95.16 93.50 93.20

Oxygen, sulphur | ^ ^

by difference / ^'^'^ ^-'^ ^'"^^ "^'^^ ^-^ 4-63 3.01 5.04 5-42

The carbon varies greatly but regularly, decreasing as one re-
cedes from the coal. No conclusions can be drawn from conditions
in the mur as the quantity is very small, but the variation in the
toit is a logarithmic curve, the cause producing the variation is in
inverse relation to distance from the coal. This seems to show
that Fremy's conclusions are right and that the shales were impreg-
nated with carbonaceous materials at expense of the coal, the com-

80

I9II.] STEVENSON— FORMATION OF COAL BEDS. 81

pounds less rich in carbon going farther. But the relations lead
to a chemical impossibility ; " a " gives CgH^o, while the coal gives
practically CieH^o-

The reason is that not all of the water of hydration goes off at
120°. To escape this error, Spring employed hydrofluoric acid and
continued the solution until the ash was about 10 per cent., the same
with that of many coals. Analysis of the residues gave these ratios ;

"a" "b" "c" "d" '' e " i 23

C:H 24.80 30.45 36 ? ? i9-8o ? ?

The results for " d "' and " e " are uncertain as are also those
for 2 and 3, the hydrogen being present in such small quantity. De-
termining the absolute relation of hydrogen he has

Coal 'a." "b" "c" " d " "e" i 2 3

Carbon 88.61 7.54 3.35 2.21 1.20 0.70 0.99 0.93 0.80

Hydrogen 4.65 0.30 o.ir 0.06 ? ? 0.05 ? ?

C : H 19.09 24.28 30.45 36.00 ? ? 19.80 ? ?

The relation of carbon and hydrogen in the mur is very nearly
the same as in the coal; it contains particles of coal little altered.
But the toit results are remarkable ; the hydrogen diminishes in
relation to the carbon and in " d " and " e " it is no longer in appre-
ciable quantity. Evidently the roof shales are not impregnated by
volatile materials coming from the coal, as required by Fremy's
theory. The transformation of the vegetable matter is rather by
ulmic fermentation. Within the primitive marshy mass the plant
substances have yielded ulmic materials while becoming richer in
carbon. These have impregnated the whole and have been modified
by external agencies.

The doctrine of transport seems to be out of harmony wath the
results as by it one would have difiiculty in explaining the richness
in carbon characterizing the toit. The alluvium, because of its
physical nature, could not support a sufficient vegetation. If one
suggest that the alluvium at its origin was mingled with much vege-
table debris, it may not be superfluous to ask if the plants could
remain on slopes, denuded and torn up by the flood which had swept
away the most thoroughly rooted plants. Everything speaks of
origin in situ. But returning to the analyses.

PROC. AMER. PHIL. SOC, L. I98 F, PRINTED APRIL 25, IQII.

81

82 STEVENSON— FORMATION OF COAL BEDS. [April 21.

If the alluvium covering the peat bogs came gradually it would
be mingled with a greater or less quantity of vegetables, which had
to undergo the same changes as the underlying mass in order to
become coal. One ought to find in the alluvium the same propor-
tion of carbon and hydrogen as in the coal itself, or at least nearly
so. If this relation do not exist, evidently some external influence
has been exerted. And the relation does not exist; the variation
increases as one recedes from the coal ; this irregularity must be
due to some slow action becoming appreciable through lapse of
time. Everything seems to indicate that slow oxidation went on in
the shales, acting chiefly on the hydrogen, for which oxygen has
the greater affinity, so that it has converted the vegetable matter into
anthracite in the more distant part of the shales.

According to diis conception, coal with abundant gas could have
been formed only when the material was protected against atmos-
pheric agencies. The many varieties of coal owe their origin
rather to unequal degrees of protection ; the fattest coals give off the
most abundant grisou — evidence that the enclosing rocks are im-
permeable.

Wild®^ in describing the Lancashire coal-field, referred to the
" bullions " which are characteristic of the Mountain-Four-foot coal
bed. These, embedded in the coal, are ferro-calcareous " concre-
tions" more or less pyritous, frequently enclosing mineralized wood,
" showing the woody and cellular structure of the plants which
have produced the seams of coal from which the concretions are
extracted." Shells are absent, the nodules being for the most part
fossil wood in varying degrees of preservation. The coal bed is
persistent and its roof shale contains concretions, known as " baum-
pots," which at times are embedded partly in the coal. These are
ironstone or calcareous, sometimes weigh 40 pounds and contain
marine shells but rarely any wood.

After a review of all the coal beds he considered the question of
their formation. The generally accepted theory that coal comes
from growth in situ seems to be a natural conclusion, for the roots
in the underclay pass through several layers. It is true that under-

*' G. Wild, "Lower Coal Measures of Lancashire," Trans. Manchester
Geol. Soc, Vol. XXL, 1892, pp. 364 et seq.

82

I9II.] STEVENSON— FORMATION OF COAL BEDS. 83

clav is not essential for vegetable growth, but more than three
fourths of the coal beds have it. The " bullions," composed of fossil
wood, occasionally show rootlets working their way through the
decaying wood, separating the fibers which now surround them.
The fossil wood is often parallel to the bedding of the coal, a condi-
tion familiar in prostrate forests and in peat accumulations. Erect
trunks and stems are unusual both in coal and peat. The underclay
was the land surface which supported vegetation like the forests
of swamps where warmth and moisture prevail.

If coal is to be considered as derived from drifted material,
he is puzzled to discover what has become of the shells and fishes,
which must have abounded in the tracts of water in wiiich the
deposits were laid down. To float some of the large trees either
vertically or horizontally, with their outspread roots having a radius
of 15 to 20 feet, would certainly require enough water to accommo-
date fishes and mollusks. Remains of fishes are not necessarily de-
stroyed by embedding them in coal-forming material, and shells are
as capable of resisting destruction as fish spines are. Shells and
fish remains occur often in impure cannel. The " bullions " have
yielded no shells, and fish remains are very rare in pure coal. That
the trees were forest growth is proved by the splendid specimens in
the ]^Ianchester and other museums.

Estuarial swamps with intermittent subsidence, permitting de-
position of sand and mud, would explain alternations of coal and
other strata, whichever theory of coal accumulation be accepted.
Marine conditions frequently followed directly upon formation of
a coal bed ; fishes of shark-like types are in shales directly overlying
coal at many horizons. But shells and fish are unknown in the
underclay.

Orton,^- in his description of the coal-fields of Ohio, considers
the various theories of formation ; some of them appear to be based
on merely local conditions, others are extravagant and only a very
small proportion of the explanations seems to have been the result
of careful observation in extensive areas.

In a coal-field, one finds a system which can be explained onh'
by subsidence. Limestone is found above and below coal beds and

*-E. Orton. Geol. Survey of Ohio, Vol. VII,, Antioch, 1893, pp. 256-262.

83

84 STEVENSON— FORMATION OF COAL BEDS. [April 21.

is accompanied by iron ore. The coal beds, though variable, are
wonderfully persistent and are always associated with fireclay.
There is no haphazard mode of occurrence. Coal is product of land
life; limestone is of marine origin; the ore depends on life for con-
centration ; sandstone, occupying the intervals between other rocks,
is due to inorganic forces and it may be about equivalent to the
others. Orton's conclusions based on more than twenty years of
study in much of the Appalachian basin, are:

(i) The Ohio coal-field, at the beginning of the Carboniferous,
was an arm of the sea with the Cincinnati arch as the western boun-
dary. (2) Marginal swamps of varying width became the earliest
coal seams by long continued growth and subsequent fossilization.
(3) While the swamps were submerged, in succession, and covered
by shale, sandstone or limestone, in turn covered by other swamps,
the continental nucleus grew slowly at the south and the Cincinnati
arch united with it by like advance eastward, expelling the waters
of the gulf and converting the earlier formed portions of the coal
formation into dry land. (4) Every coal swamp had a narrower
area than its predecessor. (5) As all coal seams were formed at
sea level, so all were raised by continental growth to an approximate
equality, which their outermost outliers still retain. (6) To look
for the earlier formed seams in the center of the basin would be
to look for the living among the dead. (7 ) In the formation of one
seam, in particular, the floor of the gulf, around which the swamps
were growing, seems to have been raised nearly to sea level at many
points, and coal appears to have been formed in island-like masses
over much wider areas than any single marginal swamp would
account for.

Bolton^''" describes a peculiar deposit of coal in Ireland. The
Jarrow coal bed appears to be a great cake, attaining a maximum
thickness of 16 feet and thinning in all directions except toward
the west, in which direction no tests have been made. I'nderclay is
absent at almost all localities. The lower part of the deposit is a
smutty anthracite with slaty structure and containing abundance of

"Mf. ]'>i)llnn, " Notes on tlio Plant and Fisli remains from the Jarrow Col-
liery, Co. Kilkenny," Trans. Manchester Gcol. Soc, Vol. XXII., 1894.

84

I9I1.] STEVENSON— FORMATION OF COAL BEDS. 85

Lcpidodcndrou stems. The upper part is a pure typical anthracite.
Fish rQn\^ms.,Gyranthus,Mcgalichthys,e\.c.,occ\.\r throughout. The
plant remains are Halonia, in the form of crushed cyhnders of
wood. This condition and the mingUng of fish remains led Bolton
to conceive that the deposit was due to the bursting of a lagoon-like
swamp and to the discharge of vegetable debris, consisting of bottom
accumulations as well as of the twigs, etc., on the surface. He
refers, for illustration, to the bursting of Solway moss in 1771,
which spread over a square mile of ground, giving a mass of vege-
table matter, 30 to 40 feet deep, demolishing houses, overturning
trees and so contaminating the Esk that no salmon ventured into
the river during that year.

Kuntze** took up the discussion from a botanist's standpoint and
advanced a wholly new theory. He antagonized v. Giimbel's con-
clusions which he maintains are wholly at variance with that
observer's facts. His own studies from 1879 to 1883 had shown
that the Carboniferous flora was sylvo-marine, a floating vegetation.
The objection that marine forms are wanting does not hold good:
the forms, described by v. Giimbel as resembling algae, are chitinous
bryozoans related to Aidopora. These, as stated by v. Giimbel,
occur abundantly in cannel and make up a great part of the boghead
coals. Carboniferous coals contain much sodium chloride, one
fourth to one half kilogram per ton; Tertiary coals contain none.
It is certain that the Carboniferous coals are not allochthonous ; the
flora must have been marine.

He contends that students have failed to interpret Stigmaria
rightly, for the appendices, regarded as rootlets, are water leaves.
The Stigmaria, with intertwining rhizomas and hollow stems rising
above the water, formed floating islands. When overloaded, they
sank to the bottom and through the mud until checked by some
harder rock. He agrees with Potonie's conclusion that they ars not
allochthonous but he cannot concede that the underclay or clay shale
is a petrified humus, for the clay is no more a soil than are the
granite and other silicious rocks with which coal beds are often in

" O. Kuntze, " Geogenetische Beitrage,"' Leipzig. 1895, PP- 4-2-77- Sincl
Carbonkohlen autochthon, allochthon oder pclagochthon ?

85

86 STEVENSON— FORMATION OF COAL BEDS. [April 21.

contact. The thickness and extent of some coal deposits are serious
objections to growth in situ. Richthofen describes a bed in China,
20 to 30 feet thick and having an area of 600 German square miles.
This would require at least 400 feet of plant remains. The bottom
three feet might have been a soil in which Stig}iiai'ia rhizomas could
have grown, but the sturdiest defender of autochthony would be at
loss to find a soil for the remaining 397 feet. Such a deposit could
have been made only by a matt of sylvo-marine vegetation.

All allochthonous and land basin theories are untenable because
transportation yields no undisturbed sedimentation ; there is no
transportation of organic detritus without contemporaneous trans-
portation of inorganic material — the transportation of purely plant
detritus is a superstition ; subsiding land basins giving 7,000 me-
ters of Carboniferous rocks, while neighboring basins subside at
different rates, would be a marvel, for in order to account for
the thick mineral beds the process of coal making would have to
be intermitted a hundred times ; there are no basins so great as those
of coal sedimentation. The four great deltas do not equal the
Pennsylvania coal-field alone ; Richthofen's southeast Shansi field
would require a basin sixteen times as large as the Caspian sea.
The great basins must have been sea basins and a sylvo-marine
forest alone explains the intermittent deposit of coal, the clays being
due to influence of streams.

Kuntze classifies the theories as Autochthony, the irregular de-
posit of the coal-producing substance directly on the place of vegeta-
tion ; Allochthony, the irregular deposit of coarse coal-producing
substance on a distant place ; onl}- the powdery substance is depos-
ited after the manner of sediments.

Pelagochthony, the sedimentary deposit of coarse substance in
water of the sea directly under the vegetation ; a secondary product
is the powdery detritus sometimes floated away from the coal magma
and deposited elsewhere as anthracite.

Autochthonous types are found in tropical or subtropical brown
coal from wood-covered bogs, witlujut s])hagnum; newer peats in
cooler regions with sphagnum ; shore swamps and some others.

Allochthonous types are drift woods; sedimentary peats; sea

80

I9II.] STEVENSON— FORMATION OF COAL BEDS. 87

peat; paper peat, which is a bituminous clay with infusoria; Blatter-
kohle, a marly clay with a little sedimentary peat.

Pelagochthonous types are : ( i ) Normal Carboniferous coal fields.
The coal beds have originated from floating forests and remains of
rooted trees occur in very limited localities. Naumann's paralic
coal-fields belong here; they are found in America, China, etc. (2)
Sea basin deposits, consisting of limited but often very thick beds,
the coal frequently thinning seaward ; these contain, besides sylvo-
marine remains, abundant remains of trees rooted in clay. Best
seen in France. Here, in part, Naumann's limnic basins. (3)
Amorphous anthracite, consisting of the finest detritus and forming
irregular deposits; does not include Faser-, Staub-or Koksanthracite
coal.

Penhallow*^ has given the results obtained by study of cannel-
like coal from the lower Alesozoic of British Columbia. All the
samples are composed of rod-like bodies more or less closely com-
pressed, which resemble dark amber and are embedded in a cement-
ing material. The rods show tubules within, many of them branch-
ing, which are very suggestive of Mycelium; granulations are com-
mon and often form zones around hyaloid areas. The features
revealed by the microscope are :

(i) Absence of structure, (2) tubular ramuli of diverse dimen-
sions, (3) rounded cavities, (4) large proportion of material in
angular fragments and resembling that of the rods, (5) an amor-
phous substance, associated with (4), occurring as distinct flakes or
as cement to unite the rods.

Appearance of structure was observed in only one rod and in
that case it is evidently due to shrinkage; he thinks the spore-like
aggregations are of chemical rather than of organic origin. The
general character of the ramuli at once suggest Mycelium, but the
intimate features and the arrangement forbid reference to vegetable
structure. They rather resemble effects of internal shrinkage, fol-
lowing hardening of the outer layer, such as one sees in amber and
other resins. The material occupying spaces between the rods and

*° D. P. Penhallow, " A Preliminary Examination of So-called Cannel
Coal from the Kootanie of British Columbia," Amcr. Geologist, X., 1892, pp.
331-339-

87

88 STEVENSON— FORMATION OF COAL BEDS. [April 21.

apparently cementing them " consists of an amorphous and irregular
mass full of rounded holes, therehy giving it a spongy character."
It contains fragments of perhaps broken rods, the material in both
being the same. The source of the amorphous material is not
certain.

Penhallow offers no positive hypothesis respecting the origin of
these coals, though he is inclined to think that it must be " sought
elsewhere than in modified vegetable structure." At the same time,
he feels that the evidence is not sufficient to justify the assertion that
they did not originate in vegetable structure.

In 1892 and 1893 there appeared papers by Bertrand and Renault
describing Bogheads and related types. Afterwards those observers
published their results independently. The later studies of Renault
concern the matter in hand only indirectly and they will receive
consideration in another portion of this work. It is necessary, how-
ever, to make detailed reference to Bertrand's contributions, for,
though they consider similar topics, the conclusions have a notable
bearing on the formation of coal beds ; and in this connection, the
stratigraphical relations of the several types must be given. With-
out that one cannot appreciate the full bearing of the studies. The
joint study by Bertrand and Renault''*^ was of boghead obtained
from Permian beds at Autun, France. This deposit occupies an
area of 7 kilometers by 150 to 450 meters. The chief constituent
is a thallophyte, Pila bibractciisis, which makes up about three fourths
of the mass ; the remaining fourth being the " fundamental mate-
rial " with some clay. A'egetable debris is wanting, but pollen of
Cordaitcs and remains of fishes are present.

These observers recognized the bodies of yellow, red and other
tints, which had been mentioned by earlier students, but their study
proved that " certain resin-like bodies represent the organic gelose
and even entire organisms. A great proportion of the yellow and
red bodies enclosed in coals are in this category and M. P. F.
Reinsch has the great merit of making this known." The inferior
gelatinous plants have been preserved in this way when buried in

^"C. Eg. Bertrand ct B. Renault, " Pila bihractcnsis et le boghead d'Autun,"
Bull. Soc. d'Hist. Nat. d'Autun, V., 1892, Separate, pp. 95, pi. 2.

88

I9II-] STEVENSOX— FORMATION OF COAL BEDS. 89

ulmic materials. The Autun boghead, 24 to 25 cm. thick, is not an
accumulation of resinous pellets clue to injection of hydrocarbons
into plant debris, but it consists of 1,600 to 1,800 beds of algse, which
sank to the bottom along with grains of pollen and the fundamental
material as well as the detritus. The fundamental material is brown,
rather flocculent and feebly colored. It is a precipitated brown
substance analogous to the ulmic matters which color the Amazon
and certain of its affluents. It contains particles of a darker mate-
rial, thelotite. an infiltration which penetrates the thalli.

The Pilas were alg?e of very low type. Their isolation in the
fundamental material, their accumulation in beds, with traces of
pressure on the under surfaces, suggest that they were floating algae
like the flours d'caii. The pollen grains, usually reduced to their
coats, were a powder resting on the water with the flcurs d'cau.
The accumulation, which may have been very rapid, was only an
incident in the formation of bituminous shale. It was made in
quiet waters, with little or no current, and so rapidly that putrefac-
tion could not begin in the mass. The deposit was laid down prob-
ably in shallow brown waters, like those of the Amazon region,
whose acidity is unfavorable to development of many bacteria.
Nearby, were forests of Cordaitcs, which furnished the pollen.

The second paper by the same authors**' gives results of study
of the so-called kerosene shale of Xew South Wales, which had
been utilized as a source of gas and illuminating oil. This shale,
known as Hartley mineral, Wollogongite and, in some reports as
Torbanite, is of uncertain occurrence. [Mackenzie''^ says that the
deposits are very irregular, there being no guide to discovery except
the presence of fragments at or below the outcrop. Toward the
border of a mass, the rich mineral becomes deteriorated and grad-
ually passes into indurated clay, bituminous or non-bituminous shale,
coal or ironstone. It occurs at two horizons in the Permo-Carbo-
niferous of New South Wales, the most notable deposits being in
the Upper Coal Aleasures, including the well-known areas of Hart-

" C. Eg. Bertrand et B. Renault. " Reinschia australis et premieres re-
marques sur le kerosene shale de la Nouvelle-Galles du Sud," Bull. Soc. Hist.
Nat. d'Aufun, VI., 1893. Separate, pp. 105, pi. 7.

** J. ^Mackenzie, Ann. Rep. Dept. of Mines for 1896, p. 100.

89

90 STEVENSON— FORMATION OF COAL BEDS. [April 21.

ley, Joadja creek and Wollongong at the south and Murrurundi
(Doughboy hollow) at the north. The only important deposit in
the Lower Coal Measures is at Greta near Newcastle in northeast
port of the province.

Long ago, Clarke®'* recognized the close resemblance of this
mineral to the boghead or Torbanite of Scotland. He thought it
due to local decomposition of some resinous wood and believed that
the lens-form of the deposits and their passage laterally into shale
could be explained easily by supposing the mineral to be due to
drifted resinous trees, undergoing changes in shallow pools sur-
rounded by material changing into ordinary coal. The quartzose
constituents are merely sand carried by wind into the pool. The
thickness of the deposit depended only on the supply of drift timber.

Wilkinson"" says that the kerosene shale occurs in irregular
lenses, sometimes in actual contact with layers of coal as at Joadja
creek, sometimes wholly unassociated with layers of coal, as at
Hartley, or even as forming part of a great coal bed, as at Greta.
At the last locality, the boghead is a great lens in the coal, but there
are many petty lenses of the same material scattered through the
coal benches. At Joadja, one finds small irregular patches of bright
jet-like material, plant remains lying horizontally and numerous
vertical stems of J\vtcbraria. whose lustrous bright jet substance is
in contrast with the dull luster of the shale.

David''^ found the shale in one place at the bottom of a great
coal bed; Mackenzie''- found it at the top in another; while in still
another David found a mass of alternating coal, clay and " shale,"
five beds of the boghead and four of bituminous coal. xAt the last
locality the whole mass thinned out in one direction, the several
layers disappearing in succession until the last layer of boghead
passed into bituminous shale. There he saw many stems of Verte-
braria, both vertical and i)rostrate; in one tunnel, some of them four

*" VV. B. Clarke, "Mines and Mineral Statistics of New Soutli Wales,"
Sydney, 1875, pp. 17^-180.

'^ C. S. Wilkinson, " ]\Iines and Min. Stat., 1875," p. 131; Ann. Rep. Dept.
Mines, 1884, pp. 149, 156; i8go, p. 208.

"T. W. E. David, Ann. Rep. Dept. Mines, 1888, p. 170: 1890, pp. 221-224;
1892, pp. 159-163.

"-J. Alackenzie, Rep. 1895, p. 104.

90

I9IT.] STEVENSON— FORMATION OF COAL BEDS. 91

inches in diameter were converted into coal. ^Mineral charcoal is
abundant in a mine in Camden County, while at Murrurundi the
boghead " contains numerous fragments of mother-of-coal and small
fragments of what appears to be coniferous wood like Arancaria,
together with coniferous fruit."

In the pages already cited, David gives ten analyses by Mungaye,
which show that at Murrurundi the ash varies from ly to 68 per
cent, and the fuel ratio from o.ii to 0.24; while at Ketoomba eight
analyses show ash from 10.7 to 78.1 and the fuel ratio from 0.13
to 1. 10. A specimen from Joadja Creek had "jy per cent, of silica
in the ash.

The material studied by Bertrand and Renault consisted of two
great blocks, one in Paris and the other in Brussels, each more than
one meter thick, apparently the full thickness of the deposit. Like
the Autun mineral, the kerosene shale consists of a fundamental
brown, flocculent material, holding alg?e and remains of dead plant
tissues. The algae are assigned to the genus Rcinschia, now ex-
tinct, but belonging to a group which was spread widely during
Permo-Carboniferous times. The alg^e are all separate, though, at
times, owing to paucity of the fundamental matter, they are in con-
tact, they are still independent. They were free, floating on the
surface of absolutely tranquil brown water, and they rained down
upon the bottom, while at the same time, under the influence of cal-
careous waters, an ulmic jelly was precipitated to form the funda-
mental material. The great specimen in the Paris ^Museum shows
36,000 beds of these alg^e, but the proportion of algae varies in the
several layers from 0.019 to 0.900 of the whole mass. At Joadja
creek the mineral is often beautiful, with a satin-like homogeneous
surface, and it consists almost wholly of the alga?.

Infiltrations are here as at Autun. The most important is red-
brown, in strings or sheets, and shows fluidal structure ; it is harder
than the fundamental material ; it often impregnates leaves and
wood ; some plants have the property of absorbing this to a notable
extent. Its mode of occurrence and its tendency to penetrate the
substance of plant remains suggest great resemblance to the thelotite
of Autun. The authors make no attempt to decide respecting the

91

92 STEVENSON— FORMATION OF COAL BEDS. [April 21.

source of this infiltration ; they are convinced that it penetrated the
deposit, if not contemporaneously, at least very soon after its forma-
tion and they suggest that it may be a kind of asphaltum, like that
of lake Brea in Trinidad. The kerosene shale contains no animals
except at ^lurrurundi, where some coprolites have been discovered.
It is a charbon produced by unaltered gelosic organisms.

Bertrand's''^ later studies were published in a series of papers,
his conclusions being summed up in a memoir presented to the
Geological Congress at Paris in 1900.

The bogheads, typified by deposits at Autun of France, the Tor-
banite of Scotland and the kerosene shale of New South Wales are
charbons gelosiques of Bertrand, accumulations of fresh water algae
in a humic jelly, their fossilization being in the presence of bitumen.
The basal material of all is a clear brown fundamental jelly, the
dull part of the bogheads and the same as the basal material of
V. Giimbel's Mattkohle. Spores and pollen have undergone macera-
tion, but they did not liquefy. They gave two kinds of yellow
bodies and they condensed bitumen strongly. When they abound,
the coal, though dull, is brighter than mattkohle. Debris of vege-
table matter, also a contribution by the wind, is distributed irregu-
larly. The hardened tissues are usually brilliant, prismatic like
v. Giimbel's Glanzkohle. Wood and barks can be found as brilliant
coal, but this depends less on their organic nature than on the extent
of alteration and their capacity to imbibe bitumen. A^getation
along river banks yielded tree-trunks, which, after imbibing bitu-
men, were converted into bright coal.

The alg?e were flcurs d'caii. They consisted of gelose and a
little protoplasm, which, when humefied, would condense bitumen.
They descended in sheets with other accidental bodies ; in times of
low water, the descent would be very slow, Ijeing impeded by the

°^ C. Eg. Bertrand, i, " Xouvcllcs rcniarques sur Ic kerosene shale de
Nouv, Galles du Sud.," Bull. Soc. d'Hist. Nat. d'Autuii, IX., i8g6; 2, 3, "Con-
ferences sur les charbons de tcrre," Bull. Soc. Beige de Geol., etc., VII., 1894;
XI., i8f;8; (4) Caracteristiques dii kerosene shale," Assoc. Franc, pour
ravancon. dcs .SV;., 1807; (5) " Lcs charbons humiques et les charbons de
purins," Traz\ et Mem. dc rVnk\ dc Lille, W., 1898; (6) C. R. du Congres
Int. de Geol., Paris, igoo, pp. 458-407.

92

'9"] STEVENSON— FORMATION OF COAL BEDS. 93

fundamental jelly. Each ball of gelose yielded a little mass of
glassy, transparent gold-yellow hydrocarbon.

The bituminous matter found in all is wholly dilTerent from the
fundamental material. There is proof of its intervention, for it
follows clefts made by contraction of the fundamental material,
which it does not color. The coalilied stems of Vcrtcbraria on
Joadja creek are humefied vegetable material charged with bitumen.
There is no evidence that this bituminous enrichment was due to
condensation of resinous matter held in suspension by the funda-
mental material ; nor is there any evidence that the fundamental
material originated from alteration of the enclosed bodies.

The accumulation could be made with remarkable rapidity. A
few good days with low water would suffice. All the accidental
bodies, enveloped in a humic coagulum, make a raft on the abso-
lutely tranquil water. A very slight cause, colder weather, more
water, would hinder formation of gelose and cause descent. The
precipitation of brown matter was continuous but formation of
gelosic matter was fortuitous ; with check of algic growth, the deposit
passes over to a humic coal or organic shale. The vegeto-humic
deposit was fixed at once and remained unaltered. The fossiliza-
tion was in the presence of bitumen, which became altered so as to
be insoluble in the ordinary solvents of asphaltum.***

Bertrand's charbons humiques differ from the charbons gelo-
siques in that the fundamental matter is not diluted with foreign
bodies. They are typified by the Broxburn shales of Scotland, con-
taining, according to Cadell, about 75 per cent, of ash. Accidental
bodies, such as algse, spores, pollen, vegetable debris are in small
proportion. Bitumen penetrated through the fundamental jelly and
enriched the shale. Bertrand finds no evidence that this bitumen
is a leakage or exudation from a fermenting vegetable mass ; he
believes that it was in the water and that it penetrated the accidental
bodies only with difficulty.

'* After the memoir was read in the Paris congress, de Lapparent asked
what is to be understood by the term " bitumen." Bertrand replied that " the
term bitumen implied for him the idea of a substance charged with carbon
and hydrogen, intervening wholly formed in the rock.'"

9a

94 STEVENSON— FORMATION OF COAL BEDS. [April 21.

Gresley^^ called attention to the persistence of slate partings in
the Pittsburgh coal bed as having an important bearing on the
origin of coal beds. Two of them, one fourth to one half inch thick
and separated by 3 to 4 inches of coal, are present in an area of
15,000 square miles. Under the lower one is a coal bench somewhat
more than 2 feet thick, while above the upper one is a bench varying
from 3 to 5 feet. The clay of the thin binders or slate partings is
extremely fine grained, mottled, non-plastic, contains macrospores
and indefinite plant remains, but no Stigmaria.

Accepting in full the doctrine of transport, he assumes that, at
the close of deposition of the lowest bench, that mass of vegetable
matter lay practically level on the bottom of a vast lake or inland
sea. Such being the condition he finds difficulty in explaining the
overlying shale as due to fine material brought in by currents ; the
shale is uniform in thickness and composition over a great area, so
that the supply of material must have been uniform throughout;
there could have been no changes in currents or offshore conditions
during the period of deposition. The quantity is not less than 100
tons per acre. He finds equal dit^culty in the suggestions that the
shale consists of wind-blown dust, that it is a precipitate from solu-
tion, that it is concretionary. The supposition that these shales are
substitution or replacement formations or that there was a segrega-
tion of inorganic substances during solidification or the process of
coal- forming involves serious difficulties. " To suppose that such
shale bands were originally thin films of chalky mud, since chem-
ically converted into silica, alumina, iron, etc., would, I think, be
exceedingly unsafe." At the same time, he suggests that the globi-
gerina ooze, widespread " over the bottom of the Atlantic, where
deepest and farthest from land would seem to furnish us with about
the only way (as to physical conditions) in which our shale binders
in the 'Pittsburg' coal bed can be imagined to have accumulated."
If the lower slate binder was really deposited as silt by aqueous
transportation, the interesting query presents itself, How could the
succeeding 4 inches of coal be formed in situ?

"^W. S. Greslcy, "The Slate Binders of the Pittsburg Coal Bed," Amcr.
Geologist, XIV., 1894, pp. 356-395-

94

19".] STEVEXSOX— FORMATION OF COAL BEDS. 95

The Pittsburgh coal bed thickens toward the southeast and the
slate partings, as well, thicken in that direction. The evidence favors
the assumption that the organic as well as the inorganic materials
came from the land surface in that direction. The absence of
Stigmaria casts reasonable doubt upon the hypothesis of formation
in situ, and this doubt is increased by the discovery of an aquatic
fauna in the underclay of the bed, which Gresley has found to be a
calcareous shale.

The extraordinary uniformity of the Pittsburgh coal bed in
purity and structure, the evenness and geographical extent of its
several divisions make it the most remarkable known. In explana-
tion of its phenomena, about all that can be said safely is " that,
everything being horizontally stratified, every part of it was most
likely accumulated under water. I have therefore come to the con-
clusion that this coal is the accumulated remains on the bottom of
a lake or sea of vegetable growth of aquatic forms (though much
of it did not necessarily grow iu the water) living afloat and dying
and decaying, falling through the water." All the familiar phe-
nomena can only be explained by an aqueous origin for the coal.

The problem of coal accumulation attracted Potonie's attention
in 1886 but he published no results of direct study until 1895. ''•' In
that year he had opportunity to study a core obtained in the Upper
Silesian coal field. This core, 750 meters long, one to 2 decimeters
in diameter, begins in Saarbruck beds and ends in the Upper Ostrau
deposits. As submitted to Potonie, it was complete and it was
studied by him in company with C. Gaebler of Breslau. The core
shows not less than 2"/ coal beds, each of which is in direct contact
with a Stigmaria underclay ; in most of them, remains of Sigillana
are present and some contain Lcpidodcndron — particularly in the
accompanying carboniferous shale.

Ochsenius, who urged the allochthonous origin of coal beds,
explained cases, such as are present in the core, as due to local
subsidences and thought them of rare occurrence. But Potonie, as
an outgrowth of broad observation, asserts that these cases are

"^ H. Potonie, " Ueber Autochthonie von Carbonkohlen-Flotzen und des
Senftenberger Braunkohlen-Flotzes, Jahrh. d. k. preuss. geolog. Landesanstalt
fiir 1895, PP- 31, pl- 2.

95

96 STEVENSON— FORMATION OF COAL BEDS. [April 21.

merely illustrations of the ordinary conditions. " The allochthonous
formation of fossil humus beds is not the normal, as Ochsenius
maintains, but autochthony is the normal, exactly as in the corre-
sponding beds of the present day." But this does not exclude con-
tributions from other localities. He cites the abandoned ox-bows
of the Mississippi, into which drift wood is thrown at high water,
but which are filled eventually with autochonous peat in which the
driftwood is enclosed. The existence of Stigniaria in intervening
beds is a normal thing and to be expected, as appears from condi-
tions in cypress swamps of North America. Its existence in the
coal itself is explained by autochthony, for, on that hypothesis, the
old decaying vegetation becomes soil for the new. Indeed, the
only difference between deposits of the several geological periods
is in character of the vegetation, there is none in the mode of
accumulation.

He finds a fossil swamp of the American type in the Miocene
deposits of brown coal at Gr. Raschen near Senftenberg, which con-
tains, among other plants, Taxodium distich iiiii. The brown coal
is 10 meters thick and shows several generations of forests, one
above the other, the stumps remaining rooted in the brown coal.
Everv feature of recent swamps is reproduced there except that
the humus has become brown coal. Many of the stems are hollow,
containing more or less of Schweelkohle. It is worthy of note that
an old peat bog exists on the clay overlying the brown coal, and that,
in the humose sand covering the peat, there are trunks of Piniis
silvcstris: the conditions favoring accumulation of humus continued
there until diluvial time. The Schweelkohle is due to resinous
exudations from broken parts of the tree — the familiar process of
closing wounds.

Absence of stumps in no wise proves allochthonous formation.
If the fossil moor had borne only non-resinous dicotyledons, the
Gr. Raschen condition could not have come about. The fact that
Stigmaricc are often filled with sand is no evidence of allochthony,
for hollow alder stumps in West Prussia swamps, exposed to high
water, are filled with sand even to the roots, so that they must be
cleaned out before the axe is applied.

96

I9II.] STEVENSON— FORMATIOX OF COAL BEDS. 97

In a later paper,^' Potonie says that having supported the cause
of autochthony, he must describe a deposit of allochthonous type.
The distinctions are simple ; in plants of autochthonous origin, the
more tender parts are preserved but they are practically wanting
in those of allochthonous origin. In connection with coal beds one
has to do chiefly with autochthonous plants ; but in Culm localities
he has to do with " Haecksel." shreds of plants, which are char-
acteristic of allochthony. These fragments are at time large
enough to show by their arrangement the direction of the transport-
ing current.

Allochthonous deposits of carbonaceous material have few
botanically recognizable plants ; many stems and branches, often
coal coated but with surface sculpture so obscured that determina-
tion is impossible ; stems of the Knorria type are of frequent occur-
rence ; while Stiguiaria is almost wholly absent, those which do occur
being imperfect. Sub-surface organs can be carried away only
after having been washed out from their place : other portions of
plants nuist be the essential material of a transported mass.

He presents the following contrasts.

Autochthony. Allochthony.

1. Coal beds common. i. Coal beds are.

2. Haecksel deposits absent or 2. Plant remains prevailingly

insignificant. Haecksel.

3. Determinable plants numer- 3. Few determinable plants ; if

ous, especially in roof. coal bed, Haecksel in the

4. Few indeterminable casts. roof.

5. Knorria rare. 4. Indeterminate casts abundant.

6. Abundant Stigmaria in the 5. Knorria abundant.

liegend. With their appen- 6. Stigmaria absent or rare ; they
dices. are without appendices.

7. Excellent preservation o f

ferns.

Potonie presented a brief systematic discussion of the whole

"' H. Potonie, " Die Merkmale allochthoner palaeozoischer Pflanzen-Abla-
gerungen," Xatumnss. Wochenschrift, XIV., 1899, pp. 81, 82.

PROC. AMER. PHIL. SOC, L, I98G, PRINTED APRIL 26, I9II.

97

98 STEVENSON— FORMATION OF COAL BEDS. [April 21.

subject in 1905 ;''^ since that time, in successive editions, he has
widened the scope of his inquiries until, in the fifth, the presentation
covers every phase with abundant illustration from German areas
and references to those of other lands. Only certain portions of the
work can be referred to in this place but, farther on, many citations
will be made. He approaches the subject from the double stand-
point of stratigraphy and palaeobotany.

The coals and allied substances are termed Kaustobiolithe, be-
cause they are combustible rocks of organic origin. He groups
them into — •
Sapropel deposits, originally " stinking muds " composed of aquatic

animals and plants.
Humus deposits, derived from land plants.

The former include the cannels, the oil shales and, as a derived
product, petroleum ; the latter include the ordinary brown and stone
coals. The difference in origin of the two groups is evident from
the physical composition shown by the microscope as well as by the
chemical composition, the Sapropels yielding compounds of the para-
ffine group while humus deposits yield compounds of the benzol
group. The Sapropels are formed in quiet, almost or wholly stag-
nant water and are of limited extent ; whereas the humus deposits
were formed as are the moors of to-day and are of vast extent.
He illustrates the modes of origin by description of a great bog in
northern Germany, which exhibits the passage from sapropel muds
at its shore, to the Flachmoor, well wooded ; thence by the Zwisch-
enmoor, with changing type of trees, to the Hochmoor, hour-glass in
form, which is treeless except alongside of rivulets. He compares
the conditions with those existing in sapropel and humus deposits of
the older periods. The existence of both autochthonous and alloch-
thonous deposits is recognized, but he asserts that the former have
been the prevailing type throughout and that, in every age, the
latter have played an insignificant part.

Potonie finds a strong argument for autochthony in the surpris-
ing resemblances, chemical and ]^lnsical, existing between beds of

"" H. Potonie, " Die Enstehung dcr Stcinkolile," Matimciss. IVochcnsclirift,
IV., 1005, pp. 1-12: tlic latest edition i,s "Die En.stehung der Steinkohle und
der Kanstoliiolithe iibcrliaupt," fnnfste Aufl., Berlin, 1910, pp. 225.

*J8

19"] STEVENSON— FORMATION OF COAL BEDS. 99

brown and black coal on one side and the modern Flachmoor on the
other. The laminated structure is frequently present in peat. The
vast extent of some beds of comparatively pure coal cannot be
paralleled in recent autochthonous deposits, but the latter are of
great extent in some regions, whereas no extensive areas of alloch-
thonous carbon deposits are known to exist anywhere. He lays great
stress upon the occurrence of sub-surface parts of fossil plants in the
soils where they grew, the so-called petrified humus-soils. He
emphasizes especially the mode in which the Stigiiiaria rhizomas and
their appendices penetrate the underclay of coal beds, spreading out
and interlacing in such a manner that transport is inconceivable.
They must be in place. Equally conclusive are the modes in which
roots of Calaniariacccc rhizomas occur in the clays. This almost
universal underclay was the soil in which were rooted trees introduc-
ing the moor- formation.

The occurrence of forest beds in stone- and brown-coal forma-
tion is not infrequent. He notes that at White Inch near Glasgow,
Scotland, and that near Senftenberg. Sometimes the profile is shown
in the roof ; sometimes there are successive forests embedded as
at Senftenberg, where erect stumps are associated with prostrate
trunks. These are conditions familiar to students of modern
swamps. The mode in which the Sfigmaricc have developed indi-
cates, in some localities, even the prevailing direction of the wind
at the time the trees grew. The growth of reeds in banks and the
parallel arrangement of their roots are the same in Mesozoic, Ceno-
zoic and recent deposits.

Potonie carefully distinguishes the features of autochthonous de-
posits as contrasted with those of allochthonous origin, elaborating
the discussion given in the paper just cited. He states that Stig-
maria is not rare in the Commentry basin and that his search there
for that plant was rewarded abundantly. He discovered ' a fine
autochthonous stump, with spreading stigmarian rhizomas, still re-
taining the delicate appendices, the whole occupying a space of 6
meters diameter. He found there also a fern tree, almost com-
pletely preserved and with a frond attached to the stem. He con-
cludes that the condition must have been that of great quiet to
permit so nearly complete preservation.

99

100 STEVENSON— FORMATION OF COAL BEDS. [April 21.

Potonie's description of secondary-allochthonous formations, due
to erosion and transport of materials from beds already existing,
will find place in another connection, as will also his arguments
drawn from the testimony of the fossil plants, respecting which his
authority is unquestioned.

Ochsenius"-' published man}- noteworthy papers but that of 1896
is especially important in this connection. The author recognizes the
force of the objection to allochthony — that, as running water carries
organic and inorganic materials together, the deposit should be an
indiscriminate mass of both kinds but his recent study of coal beds
in the Lahn country has convinced him that phenomena observed in
the Frische Haff present a true explanation and destroy the force of
the objection. The history of the Frische Flaff is complete since
1510.-"

The A'istula, a stream laden with everything that can be drawn
from a rich lowland province, gives off an arm at Peickel, the Nogat,
which flows northeast to the long narrow Frische Haff, separated
from the Gulf of Dantzig by the Frisch Xehrung or lowland, and
communicating with the gulf by the Pillauer Tiefs at its northern
end. For convenience of discussion, he confines his attention to the
Nogat, ignoring the old \'istula and the rivers which enter from the
east.

Under the supposed conditions, the sea having control and the
Hafif being filled with salt water, a marine bed is deposited on the
floor. Such beds occur locally at the bottom and higher up in the
series of coal deposits. Phase i of coal formation is brought about
through sanding up of Pillauer Tiefs by wave action, and the conse-
quent conversion of the Haft" into a fresh-water basin by influx from
the Nogat. The debris brought down by that river, an indiscriminate
mass of organic and inorganic material, will be deposited on the
bottom. H now the sea cut a shallow i)assage through the lowland,
floating stems and twigs would form a " rake " at the head of the

'■" C. Ocliscnius, "Die Bildung dcv Kohleiiflotzc," Verhandlungcn, II.,
Erste Ilalftc, pp. 224-230.

'""The Frische Haff is a great souiul on tlie border of the Gulf of Dantzig,
about 60 miles long by 5 to 7 miles witle. It may be compared as to super-
ficial area and position to Lake Ponchartrain on the Mississippi delta.

100

^911.] STEVEXSOX— FORMATION OF COAL BEDS. 101

passage. If the water-surface of inflowing stream be lowered, a
"barricade" of wood would accumulate in curves and narrows of
the Nogat. to become compacted in time — a familiar phenomenon in
this day. This " barricade " would prevent passage of large wood
and only fine material. " Spulgut '' would go over to be deposited as
a layer in the coal basin, /. c, the Haff. Brushwood would be caught
by the " rake " beyond. Thus a bituminous shale with plant impres-
sions and paper-like laminae of bright coal would accumulate.

Phase 2 comes with moderate height of the water. Now there
goes with the " Spulgut " also the " Sperrgut," stems, rooted stumps,
branches and the rest, which the Mstula pushes over into the Nogat ;
but the " rake " does not permit its escape to the sea, it circles round
in the basin, finally sinks and forms pure coal. So much of the mud
as does not pass through the " rake " will accumulate on the borders
or be mingled with the coal magma, as clay is in the globigerina ooze ;
or it may form bands in coal beds. Repeated sinkings of waterlevel
in the feeding stream, the Xogat in this case, would give a clay shale
like the floor as roof, the roof of the coal. Xo sand or gravel could
pass the " barricade "" but it would be heaped up there. Phase 3
comes with a high flood, which overthrows the " barricade " and
pushes all into the coal basin. The sand and gravel form sandstones
and conglomerates as roof of coal beds and formation of coal ceases.
The woody portions become at most only isolated stems buried in the
" Rollgut " ; by repeated pressure they may perhaps be pushed into
an oblique position. If the " rake " be torn away, the sea water again
enters the basin and lays down a marine bed.

This is the characteristic succession in coal bed formation. All
depends on the condition of the water-level. Changes in that cause
alternation of clay, shale, coal and psammite. and effect the sharp
mechanical separation of those substances by the easily explained
formation of " Rakes " and '" Barricades." The elevation of import-
ant mountain ranges in Carboniferous and Tertiary times afforded
abundant material for widespread lowlands, approximating sea-level.
These advanced seaward and their luxuriant forest growth yielded
material for the stone-and brown coals. Networks of rivers must
have cut through the lowlands and must have deposited their loads

101

102 STEVENSON— FOR^IATION OF COAL BEDS. [April 21.

in huge depressions. It is clear that many channels fed the coal
basin, but all worked after the same fashion. The process through-
out was that which Ochsenius terms " Barrenwirkungen " or barri-
cade action.

The memoir discusses many details, rock fragments in coal,
stumps filled with sandstone, the occurrence of gypsum, the presence
of land shells, all of which are explained very readily by the theory.
The conditions at Senftenberg, described by Potonie, are clearly due
to this barricade-action.

The numerous coal beds of the Carboniferous were deposited
quietly, but they are rarely more than 15 meters thick; whereas the
brown coal beds are comparatively few in number, show irregular
deposit and at times attain a thickness of 50 meters. The explanation
is simple. The soft plants of the Carboniferous had, at most, a
diameter of one meter and a height of 40 meters, so that they floated
easily in a few meters of water over the "barricade"; whereas the
Tertiary and Quaternary giant trees had a diameter of 10 meters and
a height of 170 meters, so that they needed a depth of, say, 15 meters
to float them over the "barricade." Clearly a depth of one meter
would sink more quickly to some centimeters so as to permit only
" Spulgut " to pass than would a depth of 15 meters— whence the
more frequent interruption of coal deposit in the Carboniferous and
the great constancy of formation in Neozoic time.

Almost all our mighty coal deposits are freshwater formations,
which came into existence through the factor of " Barrenwirkungen."
Autochthonv holds in their formation an exceedingl}- limited place
in comparison with that of allochthony.

Schmitz^'" has contributed a series of important papers to the
literature of the subject.

In 1894, he regarded the ;'// .s-/7// doctrine as merely a hypothesis.
The presence of transported pebbles in the coal itself rather favors
the doctrine that the coal is comjiosed of transported materials.

"" G. Schmitz. " A pr<)])os des cailloux roules dn liouillcr," ./«;;. Soc. Geol.
dc Bclgiquc, XXT., i8(;4, \^\^. Ixxi-lxxv; "La signification geogenique des
Stigniaria au mur des conches d'liouille," Ann. Soc. Sicnt. dc BntxcUes, XXL,
i<^07, 6 pp.; " Formation snr place de la lionillc," Kcv. des. Quest. Scicntifiqucs,
Avril, 1906, 35 ])|),. I) pi.

102

I9II.] STEVENSON— FORMATION OF COAL BEDS. 103

These pebbles, he had discovered, are much more numerous than had
been supposed. They are covered with a carbonaceous patine and
are found mostly in the lower portion of the beds ; he never saw any
in the upper portions. The patine suggests that the pebbles may have
made a long journey in fermenting pulp, and he thinks that their
presence with this coating is confirmatory of Renault's opinions re-
specting the conditions of deposition of materials composing the coal.
At the same time, the " French theory " of the origin of coal, though
probable for the ensemble of the coal formation, does not explain the
underclay. As for Belgium, the special, the constant facies of the
mur is evidence of formation in place. The convincing fact is the
presence of Stigiiiaria in the mur with interlacing of the rootlets.
Stigiiiaria remains in the roof are fragmentary.

In 1897, Schmitz reviewed Potonie's paper on Autochthonie ; he
recognizes that the mur is autochthonous but is not satisfied that that
necessarily involves the conclusion that the coal itself is autochthon-
ous also. A mur without coal is evidence of erosion, that its vege-
table cover has been washed away. If there be coal without mur, it
is allochthonous. A thick bed may be autochthonous below and
allochthonous above. While recognizing the valency of many of the
arguments presented by Potonie, he is not convinced that they are
final.

In 1906, he reviewed the whole subject. His own position in 1896
was that of uncertainty between the old doctrine of autochthony and
the new forms of allochthony presented by Fayol and Grand' Eury.
Many phenomena observed in the Belgian basins seemed to support
Fayol's hypothesis, but the mur, with Stigiiiaria, clearly in loco iiatali,
is a fact which cannot be ignored. Autochthony found its chief sup-
port in conditions observed in recent swamps, but the knowledge
of those was too imperfect to make the argument wholly satisfactory ;
so that Schmitz. at that time, was inclined to hold an intermediate
position and to think that both doctrines might be true.

But Potonie's later publication.^'^- based on the study of swamps
in a great area, goes far toward removing objections. Schmitz sum-
marizes the processes described as occurring in the formation of

^''" " Die Enstehung der Steinkohle."

103

104 STEVENSON— FORMATION OF COAL BEDS. [April 21.

Sapropel ; the gradations from peat to coal ; and asserts that all point
toward autochthony. He antagonizes conclusions drawn from the
presence of vegetable matter in material obtained by deep-sea dredg-
ing in the Gulf of Mexico, for that is mingled with ooze and proves
nothing for transport. He maintains that vegetable pulp cannot be
transported far without notable loss and he urges that black waters
from swamps soon lose their color through oxidation, as appears
from conditions in the Congo, Rio Negro and other rivers. De Lap-
parent has protested agamst the " fascination of present causes " and
Schmitz admits willingly that it is an error to seek in the present an
absolute representative of the past ; but he asserts that it is equally
an error to disregard the present in the study of the past.

Schmitz presents an elaborate argument. He traces the for-
mation of Sapropel in an arm of the sea, the encroachment of vege-
tation, the formation of a bog covered by trees — the tourbicrc
boiscc, the loss of moisture and the destruction of the forest, the for-
mation of the moss bog with Sphagnum,, Scheuchscria, etc. — the
tourbicrc bonibcc or hochmoor, which may continue to rise until it
reach the heath stage — that of final decrepitude. He shows how this
normal development is often interrupted, that a newer stage may
return to an older stage or may originate without existence of pre-
vious stages.

The wooded bogs are modern representatives of the Carbonifer-
ous type. They show conditions observed in the coal beds ; peaty
maceration disintegrates the most resistant plants so that one rarely
recognizes the parts. The mode of growth in bog plants resembles
that of the coal plants ; the root is radial not tap. He describes an
extensive bog in Hanover, in which the peat had been burned, leaving
exposed great tree-trunks, the luxurious crown existing when the bog
was wooded; if that bog had been covered with sediment during the
life of those trees, there would have been a legion of autochthonous
tree-trunks.

The immensity of the great coal areas, to be compared with the
immensity of modern bogs, must not be disregarded. One cannot
think of the great Westphalian-Belgian-English basin as a mere
lagoon to be fdlcd l)y rivers ; and Schmitz asks how vast must have

104

I9I1.] STEVENSON— FORMATION OF COAL BEDS. 105

been the low country to yield humic material for the coal beds of
that basin. He thinks that to accept the land conditions necessary
would require too great draft on one's credulity. But the case is
wholly different with the peat bog theory.

Schmitz concludes that the coal systems consist of allochthonous
rocks and autochthonous coal beds. The underclay is not a special
sediment; it is a sediment modified by the establishment of vegeta-
tion. There must have been some allochthonous deposits of carbon-
aceous matter, but they were merely local. The accumulation as a
whole was autochthonous, after the manner of the forested swamps.

Sterzel"^ thinks that very probably no theory of formation is of
universal application, the conditions being unlike in dififerent regions,
even in dififerent parts of the same region. In studying the Zwickau
region area, he became convinced that plants embedded in shales
accompanying the coal are not in their original place, for they are
broken, they are in different stages of decomposition, their remains
are mostly parallel to the stratification, and they show distinct evi-
dence of sorting due to currents of water. Plants in situ occur only
locally.

Some features favor belief in the autochthony of coal ; the narrow
variations in thickness of important beds within great areas ; the
small proportion of ash in many beds ; the localization of Stigmaria
in the Liegenden ; the occurrence of erect stems in the Hangenden.
But there are others equally favoring allochthony ; the distinct lami-
nation of the coal ; the mineral matter, often forming a considerable
part of the bed, is mostly clay, the same with that of the roof and
floor, and it tells of quiet deposition ; Stigmaria occurs abundantly in
the roof of coal beds ; erect stems are of exceptional occurrence.

The greater number of phenomena favor allochthonous origin of
the Zwickau coal beds. They were deposited in a lake basin sur-
rounded by forested swamps. The gently inflowing waters carried
little mineral matter and the plant material accumulated long time
on the bottom, where it was converted slowly into coal. When the

"'^ T. Sterzel, " Palaeontologische Character der Stcinkohlenformation
und des Rothliegenden von Zwickau in den Erlauterung zur geologischen
Specialkarte," Section Zwickau, 1891, pp. 87-142; " Mittheil. aus d. Naturw.
Sammlung d. Stadt-Chemnitz," 1903, 22 pp.

105

106 STEVENSON— FORMATION OF COAL BEDS. [April 21.

water-courses swelled, a great quantity of material, inorganic detri-
tus, was brought down to form the intervening bed, on which, when
(|uiet was restored, tlie j)lant material was deposited anew. Period-
ical changes, slight crustal movements, variation in fall of rivers,
lead to deposit of a great mass of rock over the coal bed ; the thick-
ness of this intervening rock depending on the extent and contin-
uance of those changes. When (juiet returns, the forested swamp
again expands. Many localities with particular species of plants
had been destroyed wholly and those forms do not reappear in
later beds — an explanation of the irregular occurrence of plant-
forms in the series.

The lake was comparatively deep, for the Zwickau measures are
about 400 meters thick. By accepting this hypothesis of a lake, one
finds explanation also of the origin of the great salt-content char-
acterizing the Zwickau deposits — in 1854, 400,000 kilos of sodium
chloride and 15,000 kilos of calcium chloride were obtained from
mine waters of the Tufen Planitzer beds.

In 1903, Sterzel (jualified a statement made on p. 90 of the pre-
ceding paper, which refers to the value of erect stems as evidence.
The only stems of that sort, observed by him, were " Sargdeckel,"
the " coal-pipes " of English miners. One Sigillaria stump, exam-
ined by him, was completely cut off at the base, with no trace of
Stigniaria. It had been torn from its place by running water, robbed
of basal branches and then deposited in the roof of the bed, where
its softened bottom was flattened under pressure. He notes that
the overlying rock is sharply defined, that there is no passage of
plants from the coal, such as would be the case if the place of plant-
growth were flooded by masses of rock material.

Lemiere^"* presented a memoir to the Geological Congress of
1900, which discussed the conversion of vegetable matter into coal.
In 1904, he returned to the subject and considered in addition the
manner in which coal beds accumulated. The discussion is based
largely on the assumption and conclusions of Fayol that the coal

'"^ L. Lcmicre, " Sur la transformation ties vegetaux en conil)ustibIe fos-
.siles," C. R. Congrcs Geo!, liilcni., Paris, 1901, pp. 500-520; "Formation et
recherches comparics des divers combustibles fossiles," Bull. Soc. de I'lnd.
Mill., 4""'. scr., IV., V. Published separately, 1905. Citations from pp. 70-142.

106

I9II.] STEVEXSOX— FORMATIOX OF COAL BEDS. 107

beds were formed of transported vegetable matter deposited in
basins of deep water. In this later memoir, he discusses the laws
governing deposition of inorganic materials of varying density and
shape, on lake bottoms in tranquil water, on beds of streams and on
shores exposed to the action of waves. This completed, he applies
the ascertained principles to explain the formation of coal deposits.

The basins in which those deposits were laid down were ordi-
narily gaping faults, very long except where divided transversely
b}- uplifted granite, and, in many cases, the fault is still apparent.
Streams began to flow into the basins at once. Where the fault
valley was divided transversely by uplifted granite, lake basins were
formed like Commentry, Alontvicq, etc., in which the beds are irreg-
ular. At other times the fracture valley retained its length and was
wide enough to be a strait or estuary, common to several rivers and
bordering on seas extensive enough to be aft'ected by tides and waves.
Respecting the latter he makes the frank remark : " It is hardly pos-
sible to admit that the areas of coal deposit were in direct commu-
nication with the high sea, because high-level floods are little com-
patible with free access of this [the ocean] ; now, the floods are a
condition, sine qua iion, of vegetable contributions; it is necessary,
then, to admit that the areas of deposition were lagoons, sheltered
from the ordinary tides, fronted by vast low plains, themselves
above the tides and furnishing few coarse elements to the river
load."

Other basins retaining their length, were less afifected by marine
conditions, possibly because of the narrowness or because of varia-
tions in level. Of such is the great syncline extending from Moulins
to Decazeville. The deposits are lacustrian. The form of the
depression aft'ects the speed of currents and therefore the type of
deposits; if broad, the rivers from diiTerent points form deltas, but
if narrow, the speed along the middle is such as to sweep away such
deposits. The contrasting conditions are shown by the Saint-Etienne
and Rive-de-Gier divisions of the Loire coal basin.

The vegetable matter, to form coal beds, was brought in mostly
during floods ; some of it remained afloat ; some was held in sus-
pension ; while some, which had undergone thorough maceration,

107

108 STEVENSON— FORMATION OF COAL BEDS. [April 2..

sank immediately. But all alike were deposited at last on the soaked
talus of the delta. The lake basin, in which the deposition was
made, is conceived to have been quite deep, for Lemiere's diagram
shows curves to a depth of 350 meters and the last is still at consid-
erable distance from the bottom ; it is supposed also to be large in
comparison with the breadth of the tributary streams. The impor-
tant source of plant material is the space along the streams between
the average low water line and that reached by high floods ; but the
still higher portions of the drainage area, being exposed to rain and
wind, would contribute.

During a long period of low water, little aside from inorganic
matter would be carried to the basin ; but when that was followed
by a period of heavy rains, the forested area was invaded, the vege-
table contributions were increased, while inrjrganic contributions
were decreased. The forest soil was covered with humus, which
had been accumulating without cessation. The soil, thus covered,
became increasingly unfavorable to vegetation, whose roots as
Grand' Eury says, hate to penetrate it deeply. Lemiere thinks this
a "peremptory argument against formation siir place of coal beds
formed by aerial plants very different from those which have formed
peat bogs. That the forest might continue and might renew itself
after destruction, it was necessary that the soil be cleared away at
intervals by winds, rains and especially by floods."

The humus, already macerated and denser than living plants,
was swept off first ; afterwards, the living plants would be uprooted
and broken. The macerated humus, being denser, was deposited on
the convex surfaces of the delta, while the living plants had to
become watersoaked before sinking, so that they were superimposed
upon the other plant material. They would come to rest more
abundantly in the bays between deltas, so that one should find more
of volatile matters in coal laid down within the bays than in that
deposited on the delta slopes, along the axes of the currents. The
volatile should increase as one departs from those axes but it should
decrease with the depth at which the vegetable matter was deposited.

Floating islands are possible, since a flood might tear oft' bodily
part of a forest, which, carried down, might float for a while and

108

19".] STEVENSON— FORMATION OF COAL BEDS. 109

then sink to give the appearance of growth in si tit. If the storm
continue long enough, it would wash ofif the soil itself, which would
become an intercalation in the bed. If the flood return, attaining
a higher stage than before, another area of forest region would be
torn ofif to form a new bench of coal, possibly directly on the other.
When the flood subsides, the superficial currents would find only
inorganic materials on which to act, and the first deposit would be
mud to form the roof of the coal bed, after which would follow
some sandstone and conglomerate. Between floods the vegetation
is restored and the area is increased by encroachment on the lake.
During this long interval, the flora might be changed.

Lemiere is convinced that, by his hypothesis, he has succeeded
in explaining converging beds, parallel formations and floating islets.
All are allochthonous ; aerial plants have formed no autochthonous
beds, for no erect stem has been found in the coal ; in fact, the
plants could not thrive in a humus not nitrefied. Peat cannot become
coal, as its tannic acid checks the process of conversion. He applies
his doctrine with great ingenuity to several basins in France and
finds it confirmed in all.

Lemiere^'^" has published several papers in more recent years and
he presented a resume of his opinions in 19 lO. In that he expresses
surprise that in recent congresses the dominant opinion was that
coal beds are ancient wooded-bogs buried by successive subsidences,
because this opinion involves the supposition that the coal beds were
not formed in the same way as the sterile beds which enclose and,
at times, penetrate them. This opinion is based upon palaeobotan-
ical evidence, which is often untrustworthy, providing two-edged
weapons, available equally for defenders of each theory. It is nec-
essary to discover some criterion which will be conclusive. In an
earlier paper, he had demonstrated finally in geometric form that the
peat bog theory leads to arrangement of beds unknown in nature.
In this he proposes to restudy the conditions after the same method,
avoiding palseontological discoveries, and availing himself of dis-
coveries which have the character of certitude. He describes three
types of structure observed in areas of the coal formation.

^"^ L. Lemiere, "Resume des theories sur la formation de la houillc,"'
Bull. C. R. mensitels. Soc. Ind. Min., Sept., 1910. separate, 19 pp.

109

110 STEVENSON— FORMATION OF COAL BEDS. [Apdl 21.

The first type is that of the Hainaut coal basin in Belgium, a
small area, 15 kilometers wide and separated from the Campine basin
at the northwest by 60 kilometers of older rocks, while on the south-
east it is bounded by a fault. The fossils show that, at times, this
basin communicated with the sea. The deposits are thin at the
north, where the beds have remained unaiTected by subsecjuent dis-
turbance; but they thicken to 3 kilometers toward the southerly
border of the basin, where the disturbance increases as the fault is
approached, the downthrow having caused close folding. The hinge
of movement was near the southeast bounding fault. If the peat
bogs were formed at the unvarying sea-level, the first of them should
have had, when the basin was filled, an inclination of 25 cm. per
meter and the last should be almost at sea-level, while the inter-
mediary beds should converge toward the shore line at the north-
west. The conditions being absent, it is evident from this mathe-
matical demonstration that the coal beds are not buried peat bogs.
The warning against the dangers of dependence on palaeontology
is repeated, and the necessity for the warning is proved by the dis-
covery of the Bernissart iguanodons in rocks other than those to
which the animals belonged, as well as by the possibility that some
day remains of fossil man may be discovered under a landslide from
a chalk cliff.

The second illustration is that of an area, increasing in extent
as it deepens. There, convergence of the beds toward the hinge
of movement would not be a criterion. The upper beds should be
of greater extent than the lower. This is to explain conditions
existing in the Appalachian basin, where one thick coal bed, the
Pittsburgh, has an area e(|uivalent to not less than 400 kilometers
scjuare. It is difficult to understand how materials from the anti-
clinal borders could reach the central parts of such a synclinal to
give parallel beds there. In the central parts of the basin are great
masses of red shale and beds of limestone and tlie coal beds are not
rigorously parallel. 1 le is inclined to think that the materials within
the central parts are due to precipitation ( from solution ) without
mechanical trans])orlation from the borders. ( )ne cannot assert

110

■91"] STEVEXSON— FORMATION OF COAL BEDS. Ill

positively that in this area peat bogs are excluded from consid-
eration.""^

The third illustration is from the basin of Vendee, which is an
isoclinal formation in an isoclinal valley, bounded on one side by a
fault. The reference to this area is brief. Lemiere states that the
phenomena of the faisceaux at the north and the dips in the basin
suggest, a priori, that here one has a case of peat bog formation.
But he plots the conditions in a diagram and states that, as shown
thus, they are evidently due to influence of the fault.

He concludes that the French coals as well as those of the
Franco-Belgian basin are not old peat bogs but are of alluvial origin
and that the same conclusion is probable for the coal beds of North
America. These conclusions do not proscribe the theory of peat
bogs ; on the contrary they appropriate those conditions and their
results. All that is insisted on is that, at present, we can find no
trace of successive deepenings of feeble amplitude and repeated for
each bed; but there are evidences of many subsidences, important or
at distant intervals, corresponding to the faisceaux of beds.

Lemiere, feeling himself no longer in danger of being paralyzed
by the question. Is coal formed /';/ situ or as alluvium?, proceeds to
show wherein his doctrine dififers from other forms of the transport
theory. As the distinction depends in great measure on his con-
ception of the mode in which vegetable matter was converted into
coal, the details have no place here.

This extended reference to Lemiere's publications is justified by
the fact that he has presented the characteristic of the transport
theory more fully than most of his predecessors and has attempted
to explain all the conditions as far as they are known to him.

Stainier.'"' whose numerous contributions will find consideration
in another connection, believes that formation of coal beds is essen-
tially a geological problem and he maintains that geologists have
been negligent in that they have left the discussion too long to the
palseobotanists. Fayol and Grand' Eury, by studying the matter

""The diagram, illustrating the structure in this second case, shows a
bounding fault on one side, such as limits the little basins in France.

"' X. Stainier. " De la formation des gisemcnts houillers," Bull. Soc.
Bclgc dc Gcol, XX.. igo6. p. V., pp. 112-114.

Ill

112 STEVENSON— FORMATION OF COAL BEDS. [April 21.

geologically, have succeeded in solving the problem for the basins
of central France. He hopes by following their methods to solve
the problem in the great basins of northwestern Europe.

If one study not the coal beds alone but also the whole series
of deposits in those coal basins, he finds that their strata differ in
no wise from those of terranes, whose marine origin is recognized
by all. No feature of coal. beds suggests a different origin for them.
On the contrary, when one endeavors to explain the formation of
coal beds by the in situ doctrine, he find himself, at each step, con-
tradicting the best established laws of geology. These contradic-
tions, naturally not apparent to the botanists, ought long ago to have
spurred geologists to make investigations for themselves. They
have led Stainier to believe that coal beds, like the encasing rocks,
are of purely sedimentary origin.

For him, the coal plants grew on continents, bordering great
depressions, into which meteoric agencies carried the vegetable
debris along with materials torn from the land by erosion. These
materials, vegetable and inorganic, were mingled intimately while
the water was in agitation ; but in proportion as the condition of
calm was re-established, they were thrown down to the bottom in a
well defined order, determined by density of the materials. In cases
where the succession is complete, there was formed, first, a bed of
sand, ultimately becoming a bed of sandstone; then a peculiar,
irregular rock, which constitutes the mur and contains the denser
parts of the vegetables, /. c, the sub-surface organs ; then the remain-
ing portion of the vegetable debris was deposited to form a coal bed ;
and finally, the impalpable elements, fine clays, reached the bottom,
giving tender fine shales, the roof of the coal bed.

The reasoning on which the conclusions are based is to be given
in a memoir not yet published.

Ashley'"^ has offered suggestions which are not without interest
here. Adopting the doctrine of autochthony, he ignores in his cal-
culations the cannels as well as other merely local deposits, which
are allochthonous and therefore outside of the discussion. He finds

'"*' (j. H. Ashley, " .Maxiniuin Deposition of Coal in the Appalachian Coal
Field," Ecdii. (Jcology, I., i()o6, pp. 788-793: II.. pp. 34-47: " Signiticai.t Time
Breaks in Coal Deposition," Science, N. S., XXX., 1909, p. 129.

112

I9II.] STEVENSON— FORMATION OF COAL BEDS. 113

that under exceedingly favorable conditions a peat bog has gained
one foot of thickness in five years but that in one case this increase
appeared to be only one foot in two hundred years. With the con-
ditions normal, the rate of increase seems to be not far from one
foot in ten years. Reasoning from the approximately ascertained
ratio of volume of peat and the resulting coal, he conceives that 300
years would be required for the formation of one foot of coal, thus
giving a period of about 4.000 years for accumulation of the Pitts-
burgh coal bed in western ^Maryland. The minimum period to be
assigned for formation of the 300 feet of coal in the Appalachian
basin is not far from 100.000 years.

In his later paper, seeking to ascertain whether or not a coal
bed may be utilized as a time measure, he indicates some complexities
of the problem, one of which is important. A coal bed, 18 inches
thick at one locality may be 15 feet at another, the latter thickness
requiring for accumulation 4,000 years more than the other. As the
rocks accompanying the thinner bed show no compensating differ-
ences, the 18 inches is all that was formed while the 15 feet was
accumulating elsewhere. There was either slow growth or a time-
break, that is a period of no deposition, before or after deposition
of the thin bed.

"' Smooth-partings " are evidences of time-breaks and represent
locally nonconformity between the under- and the overlying beds : a
" smooth-parting" at one place may be equivalent to 40 feet of shale
at another ; an inch or two of cannel may have similar equivalence.
Slow growth and temporary cessation of deposition are important
elements of the problem.

Dannenberg^'"* finds strong arguments in favor of autochthonous
formation in the vast extent of some coal areas, the presence of
the tenderest plant-parts in coal inclusions, the abundant occurrence
of roots directly under tlie coal, and the identity of coal-forming
plant species with those found in the enclosing shale rocks. Not all
localities show these features with equal clearness, for in some cases
there are variations along dip and strike like those in delta deposits,

'"^ A. Dannenberg, "Geologic der Steinkohlenlager, Berlin, 1909; Erster
Tell, 197 pp. The citations are from pp. 18-27.

PROC. AMER. PHIL. SOC, L. I98H, PRINTED APRIL 25, IQII.

113

114 STEVENSON— FOR^IATION OF COAL BEDS. [April 21.

such as appear in the basins of central France, which Fayol has
proved to be allochthonous.

The deposits must have been made in shallow water ; Grand'
Eury has shown that the autochthonous flora of the Loire basin
could not have grown in water more than 10 to 15 meters deep.
There must have been a special combination of circumstances, since
*the deposits, in spite of the shallowness of the water, have in some
basins a thickness of some thousands of meters. This can be under-
stood if one accept a constant though variable subsidence through-
out the period of deposition. A certain instability of coast line in
paralic basins is proved by repeated inroads of the sea. If the sedi-
ments be laid down less rapidly than the surface sinks, marine con-
ditions prevail. Periods of rest, possibly of some elevation, would
be favorable to development of swamp vegetation, which, when sub-
sidence began again, would be buried under muddy and sandy depos-
its, until a new swampy area was produced, on which vegetation
began de novo. These movements can be followed with great clear-
ness in the Saarbruck and Loire basins.

Similar movements in the period of man can be recognized along
many coasts. Dannenberg regards the Tertiary and Quaternary
history of the Netherlands as especially instructive. This he gives
in detail, showing that there have been successive advances and
retreats of the shore line, so that the section of Tertiary and Quater-
nary beds consists of sandstones, conglomerates, shales, marine beds
and peat deposits, wholly similar to the succession observed in the
Coal Measures. The filled river valleys observed in the Coal ]\Ieas-
ures, have their counterparts in these newer deposits. And it must
not be forgotten that, in the Carboniferous time, great orogenic
movements occurred, so that there was abundant material for filling
the basins.

Stevenson,^^'' after studying the area, found himself unable to
accept Fa vol's conclusions respecting the mode in which the coal
beds were formed in the basin of Commentry. He agreed fully with
Favol as to the process by which the inorganic deposits were laid

^'"J. J. Stevenson, "The Coal Basin of Commentry in Central France,"
Ann. jY. V. Acad. Sci., XIX., 1910, pp. 161-204, 6 pi.; "The Coal Basin of
Decazeville, France," the same, XX., 191 1, pp. 243-294, 2 pi.

114

191 1.] STEVEXSOX— FORMATIOX OF COAL BEDS. 115

down, seeing there the conditions of deha formation as long recog-
nized by geologists in American coal fields ; but he could discover no
reason for supposing that the coal beds were formed of plant ma-
terials washed in from the drainage area. That hypothesis, as pre-
sented for this region, seems to be self-contradictory. The supposed
surface conditions at the beginning of the history were such that
dense vegetable cover seems in the last degree improbable ; but the
vegetation required by the hypothesis was so dense, that it would
have been its own protection against any but a long-continued series
of the most terrific cloud-bursts ; in case of such a debacle, only a
small part of the vegetable matter could be deposited as a coal bed,
for the trees, supposed to have composed one half of the whole
vegetation, would be loaded by material around their roots, would
be snags in the mass of detritus and would be buried in the sands ;
even the twigs and underbrush would be entangled in the mass, for
there could be no sorting action in the short course of the little tor-
rent and all would be dropped when the flood's velocity was checked
on the comparative]}' broad delta surface, supposed to exist when
formation of the Grande Couche began. Only the finest material,
mineral, or vegetable, could find its way to the bottom of the basin —
yet it is certain that trees make up a very considerable part of the
Grande Couche. The objections presented by this writer will be con-
sidered in another connection. He thinks that the structure of the
Grande Couche shows that its vegetation accumulated /// situ and
that there is no evidence to favor the suggestion that Lake Com-
mentry was a deep water basin at the time when coal accunuilation
began.

Study of the Decazeville basin led him to similar conclusions
respecting that area. The conditions there are very different from
those in the Commentry basin, so dift'erent that any doctrine of
transport formulated to account for the conditions at Commentry
could not be applicable at Decazeville.

Studv of investigations by v. Giimbel and Potonie led Gothan"^
to studv the coal area near Fiinfkirchen. The economic importance
of the Liassic coals within that area had been known for more than

"' \V. Gothan, " Untersiichungen iiber die Entstehung der Lias-Stein-
kohlenflotze bei Fiinfkirchen (Pecs. Ungarn),"' Sifcungsbcr. d. k. prcus.
Akad., VIIL, 1910, pp. 129-143.

115

116 STEVENSON— FORMATION OF COAL BEDS. [April 21.

100 years and the relations of the beds had been described by several
geologists ; but nothing was known which showed the mode in which
the coals had accumulated. The section contains about 100 coal
beds, of which fully 25 attain workable thickness in much of the
area. Gothan had already discovered underclays with roots asso-
ciated with Mesozoic coal beds on the Yorkshire coast of England,
and it seemed probable that search for similar clays at Fiinfkirchen
would be successful.

He was not disappointed, though he found the difificulties in the
way of study greater than anticipated.

Under the coal bed, no. 7, there is a well-marked undcrclay with
irregular branching coaly markings, varying in diameter and in every
respect resembling roots ; and, at one locality, a rhizoma with its
rootlets was complete, enabling him to determine the relations of
the other forms. " Through such horizontal rhizomas, the analogy
of this Mesozoic underclay with the Carboniferous Stiginaria-heds
and the recent or sub-recent reed-beds is the more marked." A
four-inch layer of carbonaceous shale lies between the underclay and
the coal, but one cannot trace the roots in it ; they cannot be dis-
tinguished in the dark material, which is so crossed by cleavage
planes that none but irregular angular fragments can be obtained.
The planes do not coincide with the direction of the rootlets.

Roots are seldom observed in the freshly exposed rock within
the mines, but they are distinct enough where the rock is somewhat
weathered. Gothan exposed the outcrop for several meters at dif-
ferent horizons and in the course of a day's excursion, he found
well-marked underclays, with roots, associated with 8 coal beds.
The analogy with Tertiary and Quaternary underclays is complete.
His conclusions arc that the underclay, associated in more than a
dozen instances, with the Fiinfkirchen coal beds, shows that these
are, for the most part, of autochthonous origin, as are, predomi-
nantly, the younger and older humus deposits of the present time
as well as those of the Tertiary and Palaezoic. The failure to secure
])roof of this origin for all the Funfkirchcn beds is due merely to
the unfavorable conditions to which reference has been made. In
a footnote he notes his discovery of typical underclay, with roots,
just below a Wcalden coal bed in a neigliboring district.

116

THE- TRANSPIRATION OF AIR THROUGH A PARTI-
TION OF WATER.

By C. BARUS.
(Read April 21, 1911.)

1. Molecular Transpiration of a Gas. — Ever since 1895 I have
observed that the Cartesian diver, used in my lectures, grew regularly
heavier from year to year. The possibility of such an occurrence
is at hand ; for the imprisoned air is under a slight pressure-excess
as compared with the external atmospheric air. But this pressure
gradient is apparently so insignificant as compared with the long
column of water through which the flow must take place, that oppor-
tunities of obtaining quantitative evidence in favor of such trans-
piration seem remote. If, however, this evidence is here actually
forthcoming, then the experiment is of unusual interest, as it will
probably indicate the nature of the passage of a gas, molecularly,
through the intermolecular pores of a liquid. It should be possible
for instance to obtain comparisons between the dimensions of the
molecules transferred and the channels of transfer involved.

2. Apparatus. — Hence on February 27. 1890, I made a series of
definite experiments^ sufficiently sensitive that in the lapse of years
one might expect to obtain an issue. The swimmer was a small
light balloon-shaped glass vessel, vd, Fig. i, unfortunately with a
very narrow mouth, 2 mm. in diameter, at d, in the long column of
water A. The small opening however gave assurance that the air
would not be accidentally spilled in the intervening years. For this
reason it was temporarily retained, the purpose being that of getting
a safe estimate of the conditions under which flow takes place.

In Fig. I ab is a rubber hose filled with water, terminating in the
receiver R. Here the lower level of w^ater may be read ofif. More-
over R is provided with an open hose C, through which pressure or
suction may be applied by the mouth, for the purpose of raising or

^ Am. Joiini. of Sci.. IX., 1900, pp. 397-400.

117

118

BARUS— THE TRANSPIRATION OF AIR

[April 21,

lowering the swimmer, I'd, in the cohimn A. In this way constancy
of temperature is secured throughout the cohmm.

3. Barometer. — The apparatus is obviously useful for ordinary
barometric purposes, and provided the temperature, t, of the air

— M

^^T

A

N— r

Fig. I. Swimmer and appurtenances.

at V, is known to .025° C, the barometric height should be deter-
minable as far as .1 mm. Apart from this the sensitiveness of the
apparatus is surprising. Care must be taken to avoid adiabatic
changes of temperature, so that slow manipulation is essential.
These and other precautions were pointed out in the original paper
(/. c.)

4. Equations. Manipulation. — Let // be the difference of level
of the imprisoned water and the free surface in the reservoir R.
Then it follows easilv that

/ _L // P'- - J^^'J '^

P. ~ S^I {i+mlM)-pJp'

(0

where // is the corrected height of the barometer (from which the
mercury head ecjuivalcnt to the vaptn" pressure of water is to be

I9II.]

THROUGH A PARTITION OF WATER.

119

deducted), /3„,, puu pg, the densities of mercury (o° C), water {t° C),
and glass, respectively, m the mass of the imprisoned air at v, R its
gas constant, and T = t-\-2y2>° its absolute temperature. M is the
mass of the glass of the swimmer and g the acceleration of gravity.
The equilibrium position of the swimmer is unstable. To find it,
R may be raised and lowered for a fixed level of the swimmer; or R
may be clamped and the proper level of the swimmer determined hy
suction and release at C. The dropping of the swimmer throughout

n

A

^

~d:

--.[

r

Fig. 2. Cylindrical Swimmer.

the column of water may occasion adiabatic change of temperature
of .23°. It was my practice to use the latter method and to indicate
the equilibrium position of the swimmer by an elastic steel ring,
encircling A. In this w^ay the correct level may be found to about
I mm., and afterwards read ofi^ on the cathetometer.

After making the observations, the hose ab is to be separated at
a, so that the swimmer falls to a support some distance above the
bottom, admitting of free passage for diffusion. Clearly this dif-
fusion is due to the difference of level, h" , between the water level in
z' and at the free surface of the liquid, / (see Fig. 2). Increase of
barometric pressure has no differential effect. A large head h" how-
ever means a longer column for diffusion.

5. Data. — In the following summary a few of the data made in
1900 are inserted, chosen at random.

120 BARUS— THE TRANSPIRATION OF AIR [April 21,

In the intermediate time, I did not return to the measurements
until quite recently (January, 191 1), when a second series of obser-
vations was made. As much as one fourth of the air contained in
1900 had now, however, escaped, in consequence of which the above
method had to be modified and all heads measured in terms of
mercury. Hence if H denotes the height of the barometer diminished
by the head equivalent to the vapor pressure of water, and if m/M
be neglected in comparison with i (about .06 per cent.) the equation
becomes

R

(2)

in which the first factor of the right-hand member is constant. If
the observations are made at the instant the swimmer sinks from
the free surface in A, Fig. 2, H must be increased by the mercury
equivalent of the height h' of v. The table contains all the data
reduced to mercury heads. A ^Mgp„,/R. Consequently 1,842 X
10"^ grams of the imprisoned air escaped in the intervening 10.92
years ; i. c, .265 of the original mass of air. In other words
168.7 X lO""*^ grams per year, .462 X lO"*' grams per day, or 5.35 X
lO"^- grams of dry air per second.

6. Conditions of Flour. — It is now necessary to analyze the above
experiment preparatory to the computation of constants. The mouth
of the swimmer had an area of but .0314 cm.- When sunk the
head of water above the surface z' was li" = 2^ cm. The column
of water between z' and d was h"' = S> cm. Hence the length of
column within which transpiration took place was 24 -j- 2 X 8 = 40
cm. The right section of this column is taken as .0314 cm.- through-
out. Naturally such an assumption, accepted in the absence of a
better one, is somewhat precarious ; but it may be admitted, inas-
much as the pressure of the gas sinks in the same proportion in
which the breadth of the channel enlarges. Thus there must be
at least an approximate compensation. In more definite experiments
a cylindrical swimmer whose internal area is the same as the annular
area without will obviate this difficulty (see Fig. 2).

The pressure difference urging the flow of air from f is

191 1.] THROUGH A PARTITION OF WATER. 121

A/' = 24 X -997 X 981 = 23470 dynes/cm.2
Hence per dyne/cm.- per sec.

io~^^ X 5.346

10x2.347

= IO~*"X 2.25

grams of air escape from the swimmer.

A few comparisons with a case of viscous flow may here be inter-
esting. Using Poiseuille's law in the form given by O. E. Meyer
and Schumann's data for the viscosity of air, it would follow that
but .194 X 10"^ cm.- of the .0314 cm.^ of right section at d is open
to intermolecular transpiration. The assumption of capillary trans-
piration is of course unwarrantable and the comparison is made
merely to show' that relatively enormous resistances are in question.

Again the coefficient of viscosity

^ 1 !_ J^(p2_.2^

I +4^/r~"w 16 IRr^ ^ ^

may be determined directly. In this equation m is the number of
grams of air transpiring in t seconds through the section irr- and in
virtue of the pressure gradient {P — /')/i, when -q is the viscosity
and ^ the slip of the gas. Hence the value r;/(i -f 4l/r) =4.8 X 10^
would have to obtain, a resistance, which would still be enormously
large relative to the viscosity of air (t/=i.8oX io"*'), even if the
part of the section of the channel which is open to capillary tran-
spiration is a very small fraction.

7. The Coefficients of Transpiration. — To compute the constants
under which flow takes place the concentration gradient dc/dl
may be replaced either by a density gradient dp/dl or a pressure
gradient dp/dl. If the coefficients in question be k^ and kp respec-
tively

k -i^ "±^ (.\

^~ Rt~ adpjdl ^^^

where a is the section taken equal to the area of the mouth of the
swimmer, R is the absolute gas constant, r the absolute temperature
of the gas, and m the loss of imprisoned air in grams per second.
If ^; = iiiRr/p is the corresponding loss of volume at r and p

122 BARUS— THE TRANSPIRATION OF AIR [April 21,

^ Rt aRTdpjdr ^^^

If in equation (3) the full value of m is inserted and t denotes cur-
rent time, or /u = m/t; if

dl h" + 2h"'

where pw is the density of water, h" and W" the difference of level
(see Fig. 2) of the surface in v below the free surface in A and
above the mouth at d, the relations are

Alp H \-\- 2/1" I h" , , ,

k, = kRT. • (5)

The acceleration of gravity, g, has dropped from both equations ; k^
is independent of Rt. The coefficient A";,, however, is more per-
spicuous.

If h'" is made very small in comparison with /;" (care being taken
to avoid loss of air during manipulation) //" will also vanish; or
for /i" = o

and similarly for ]i" = o

reduces to

;// = k^ap^^g.

Thus the apparatus is most sensitive if a is as large as possible and
h"'/h" as small as possible and the length of the column in A is
eventually without influence on the result. Hence if for a cylindrical
swimmer the internal right section is equal to the area of the annular
space between the outer wall of the swimmer and the inner wall of
the vessel A^ if the column of water above the swimmer is removed
during the prolonged intervals of time between observations, the

I9II.] THROUGH A PARTITIOX OF WATER. 123

section a through which capillary transpiration takes place is defi-
nitely given. It is obvious that the swimmer must be suspended, for
instance by fine cross wires, above the bottom of the tank A.

Reference is finally to be made to convection and to temperature.
The manipulation during observation necessarily stirs up the water
and distorts the regular pressure gradient. Hence observations are
to be made rarely. Again to obviate convection in general the
vessel must be kept in a room of nearly constant temperature.

8. Values of the Coefficients. — If the data of the above summary
be inserted in the equations for k,, and kp,

viRr 5.15 X lO-'- X 2.87 X lo" x 298 .

^ adpjdl 10314x23470/40

/. =klRr= .29 x \o-'\

Hence for a gradient of i dyne per cm., 2.9 X lO"^^ grams of air
flow between opposed faces of a cu. cm. of water per second. This
may be put roughly as about 2.4 X iO"^° cu. cm. of air per second.
The speed of migration of individual air molecules intermolecularly
through a wall of water is thus 2.4 X lO"" cm./sec. for a dyne/cm.
gradient.

Since the. gradient is the energy expended when the cu. cm. is
transferred i cm. along the channel and if the number of air mole-
cules per cu. cm. be taken as A' = 6oX IO'^ the force acting per
molecule to give it the velocity just specified is 1/(60 X 10^^) dynes.
Hence the force or drag per molecule if its speed is to be i cm. per
sec. is

/ = Tn z 1^ = s dynes

•^ 2.4xiO"^°6ox 10'- 144 X 10^

/= 6.9 X io~'' dynes, \{ v = cm./sec.

This may be compared with the force necessary to move a small
sphere through a very viscous liquid of viscosity -q. This force is

f^fyirqrr.

If z.'=i cm./sec, 2r=iO"* X2 cm. the diameter of the sphere of
influence of a molecule, and / = 6.9XiO"^' dynes the value just
found,

124 BARUS— THE TRANSPIRATION OF AIR. [April 21,

6.9 X lO"'^ ^. „

77 = -r^ „- = 366 X IO~\

' 67rx IO~^ ^

In other words the molecule moves through a liquid about twice as
viscous as the air itself.

9. Conclusion. — The above data are subject to the different hypoth-
eses stated ; but it has been shown that the results may be obtained
by the method described free from ulterior assumption. It seems
to me that detailed investigations of the above kind carried on with
reference to both the chemical and the physical properties of the
liquid, i. e., with different liquids and different gases at different
temperatures and pressures, cannot but lead to results of importance
bearing on the molecular physics involved. Hence experiments of
this kind have been begun in this laboratory and I hope to report the
results from time to time. Obviously in a doubly closed water ma-
nometer (U-tube) the unequal heads of the two columns of liquid
must in a way similar to the above vanish in the lapse of time. This
method seems particularly well adapted to obviate convection.
Finally hydrogen shows a measurable amount of molecular tran-
spiration in the daily march of results already obtained, and with this
gas a new and direct method for obtaining the molecular diameter
is foreshadowed.

Brown University,
Providence, R. I.

ELLIPTIC INTERFERENCE WITH REFLECTING
GRATING.

By C. BARUS.

(Read April 21, 1911.)

I. First Method. — There are two or three typical cases in the
use of reflecting gratings for the production of interferences in the
spectrum, each of which shows pecuharly interesting features. The
first of these is given in Fig. i and corresponds closely to the method
described for transmission gratings in a preceding paper. If L is
the source of light and M a glass plate grating, it was shown that

Fig. I. Diagram, showing positions of mirror, M, and grating, G.

plane mirrors in the positions Ci and G,,, each reflecting a spectrum
from M^ produce elliptical interference whenever the rays returned
after passing -1/ by transmission and reflection, respectively, are made
to overlap in the spectrum, under suitable conditions.

The present method is the converse of this, since the gratings
and the opaque mirrors change places. Parallel rays from L strike
the plate of glass M and the component rays reach identical reflecting

125

126 BARUS— ELLIPTIC INTERFERENCE [April 21,

gratings Gm and G„, placed symmetrically with respect to M at an
angle / to the E and L directions. The undeviated rays pass off
eccentrically at R and are not seen in the telescope at E. They may,
however, be seen in an auxiliary telescope pointed in the line R and
they then facilitate the adjustments. Rays diffracted at the angle
2i, however, are respectively transmitted and reflected by ^1/ and
interfere in the telescope in the line E. Similarly rays diffracted at
an angle 6' > / interfere in the line D.

To make the adjustment it is sufficient to bring the Fraunhofer
lines in the two spectra seen at E into complete coincidence, hori-
zontally and vertically. Coincidence of slit images at R (at least
vertically) aids in the same result. It is also necessary that the
rulings on Gm and G„ and the slit should be parallel, or that the
images of slit and spectra shall lie between the same horizontals.
One of the gratings, C,,, may now be moved parallel to itself by the
micrometer screw until the elliptic interferences appear. If the
plate M is not half silvered there are three groups of these as
described in the preceding paper. Each group passes from the initial
degree of extreme fineness, through maximum size, to a final degree,
for a play of the screw of about i mm. There is the usual radial
motion of the fringes, together with the drift through the spectrum
as a whole. To bring out the set of solitary ellipses, the silvered
surface of M should be towards the light and remote from the eye.
As a rule the adjustment is difficult, as an extra condition is imposed
in the parallelism of the slit and the rulings of the gratings. The
ellipses are liable to be coarse with their axes oljlique. clearer in some
parts of the spectrum than in others, unless means are provided for
placing the rulings accurately parallel. Even when well adjusted
they are rather polygonal than rounded in their contours. They are
about as strong with non-silvered glass M as with half-silvered glass ;
but in view of the multij^le spectra the adjustment is much more
difficult in the former case.

It has been suggested that the white slit images must appear
eccentrically in the direction R. Hence if a special telescope is
directed in this line, the final adjustment is reached on coincidence
of the proper slit images, provided the rulings of the gratings and the
slit are parallel.

I9II.] WITH REFLECTING GRATING. 127

For d' > i the second series of interference spectra occurring at
D, eccentrically, are broader, but only on perfect adjustment do the\-
occur simultaneously with the other set. In fact, since for the pre-
ceding case i^=6, or

2 sin i = X/D
and in the present case,

sin 6' — sin / = X/D,
therefore

sin 6' ^2> s"i ' = 3 sin 0.

There is also an available set in the second order to the left of E.
In the gratings used above D lies in front of G,,. being nearer the E
than the L direction.

2. Inz'cysion of the Method. — The occurrence of the undeviated
ray R suggests another method. For if the white ray R is reversed,
i. e., comes from an eccentric collimator, slit images w'ill be seen in
telescopes at L and £, whereas overlapping spectra will appear in
the direction D' eccentrically and in the lines R and R' . One of the
latter may be lost in the collimator. The former occurs for the
same angle 6' so that

sin ^'^3 sin/.

Moreover, if 7 = 45° is the angle of incidence of L upon M when
sodium light is taken, so that (9' = 26° 14'. / = 8° 28', the R, D. D'
rays make angles 2i, 6' -\- i, 0' — /, respectively, with the E direction ;
or the sum of the angles at D and D' with the E line is 2O' , their
difiference 21, and the rays D, R, D' intersect at a common centre on
Gm- Hence if we place the plane of Gm at the centre of the spherom-
eter and arrange -1/ and G„ eccentrically, the angles may be meas-
ured as before.

3. Resolution of the Slit Image. — If the sharp white images of
the slit in a Michelson apparatus for the case in which the incident
light consists of parallel \vhite rays from a collimator, be accurately
superimposed and the opaque mirrors be set at the proper distances
from the semi-transparent mirror by the micrometer, the slit image
may itself be view^ed through a grating and will then show' elliptic
interferences in all the spectra. The apparatus is here eccentric,

128

BARUS— ELLIPTIC INTERFERENCE

[April 21,

while the grating (either transmitting or reflecting) must be at the
center of the spectrometer, if angles are to be measured. The same
is true for any of the other superimposed white slit images in the
above or the earlier experiments and may even be repeated with
successive transmitting gratings. It is interesting to note that the
position of the center of ellipses is at the same w^ave length in all
the spectra though the form of ellipses may differ enormously. The
same phenomenon may thus be seen by a number of observers at the
same time, each looking through his own telescope.

lU

it'-7,

>^r

3

3) 'J>'

Fig. 2.

Fig. 3-

Diagrams showing position of gratings, g, g'.

4. Third Method. Parallel Gratings. — In this case the two
halves of the grating are treated displaced parallel to themselves,
from their original coplanar position in the grating, from which
they are cut. Their mounting is thus something like the case of the
two black plates of Fresnel's mirror apparatus, one of the plates
being adapted for displacement parallel to itself.

In Fig. 2 g and g' show the two halves of the grating cut along
the plane S, normal to the plates and parallel to the rulings. The
half g' is provided with a micrometer screw, so that it may be suc-
cessively moved from the position g' in Fig. 2 tt^ the position g' in
Fig. 3, through all intermediate positions, while the half g remains
stationary. Each of the halves g and g' is controlled by three ad-
justment screws (horizontal and vertical axes of rotation), to secure
complete parallelism of the faces of the grating. Each, moreover,

15".] WITH REFLECTING GRATING. 129

n:ay be rotated around a horizontal axis to place the lines parallel
to the slit of the collimator. The duplex grating is mounted on a
spectrometer as is usual for reflection. Finally each half may be
raised and lowered and moved horizontally to and fro, parallel to
itself, so that the half gratings when coplanar may approximately
reproduce the original grating.

After each of the spectra are clear as to Fraunhofer lines, the
interferences here in question are produced by bringing these lines
(the D lines for instance) into perfect coincidence, horizontally and
vertically. Under these circumstances if the distance apart, r. is
suitably chosen, the interference fringes will appear throughout the
spectrum. These consist of an approximately equidistant series of
lines parallel to the slit, /. c, vertical lines, which are finer, ccct. par.,
as the breadth of the crack at 5 between the gratings is larger.
They may be increased from the extreme fineness as they enter the
range of visibility to a maximum coarseness (in the above experi-
ments) of about three to five minutes per fringe, after which they
vanish. They cannot, in practice, be passed through infinite size ;
neither can they be produced symmetrically on the two sides of the
adjustment for infinite size. They cannot in other words be changed
from the positive to the negative condition of appearance.

The occurrences are in fact as follows : if as in Fig 2, i > 6,
(parallel white rays coming from L and L', R and R' being reflected,
D and D' dififracted rays for the normal //), the grating g' must be
in advance or forward of ^. If now the airspace e is reduced micro-
metrically, g' retreating, the lines travel in a given direction ( from
left to right) through the spectrum, while at the same time they
grow continually larger until for a minimum value of c still positive,
they vanish as a whole. The period of indistinctness before evan-
escence is not marked.

On the other hand if 0' > /' as in Fig. 3, the grating g' must be to
the rear of g and the air space c is throughout negative. If this is
now decreased numerically the lines travel through the spectrum
in the opposite direction to the preceding case, while at the same
time they coarsen until they vanish as a whole as before. The
grating g' is still behind g when this occurs.

PROC. AMER. PHIL. SOC. L. 198 I, PRINTED .\PRIL 27, 191I.

130

BARUS— ELLIPTIC INTERFERE^CE

r April ?i.

Finally if for any suitable value of c the grating g' is moved in
its own plane without rotation away from g, so as to widen the
crack at 6^ between them, the fringes grow continually finer until
they pass beyond visibility, and vice versa ; i. e., as the crack at 6^ is
made smaller the lines continually coarsen.

5. Nature of the Evanescence. — The fact that the lines vanish
as a whole and almost suddenly after reaching their maximum dis-
tance apart is very peculiar, as is also the fact that they cannot be
passed through infinite size or appear symmetrically on both sides
of this adjustment. To investigate this case I provided both the
collimator and the telescope with slits so that the parts of the grat-
ing g and g', from which the interfering pencils come, might be
investigated.

If a single vertical slit about i mm. wide is passed from right
to left toward the objective of the telescope, a black line passe.=

Fic. 4. Diagram.

across the field of the spectrum, which line is merely the image of
the crack at 5". In the diagram Fig. 4, the G rays, for instance, conif^
from the edge of both gratings g and g' , whereas the R rays an^'
the [' rays come from but a single grating. Now when the space e

I9II.] WITH REFLECTING GRATING. 131

is diminished, the black band at G gradually vanishes and in its
place appear the coarsest fringes producible. When the slit F is
removed these coarse fringes disappear. The fringes visible
through the slit have however both an inferior and superior limit
of angular size. When e is diminished to zero they vanish and
when e is sufficiently increased they again vanish, though they now
appear when the slit is either removed or widened. From this it
follows that the coarsest fringes come from the edges of the crack
6^ of the gratings, and that the remainder of the grating will not pro-
duce coarse fringes. By moving the slit the fringes may be made
to appear in any other part of the spectrum.

The same fact may be proved by putting the vertical slit F over
the lens of the collimator and allowing the white light L to fall on
the edges of the grating at 5". Coarse fringes limited as to range
and size are then seen throughout the spectrum at g.

Whenever the slit or vertical stop is used, the fringes are ex-
ceptionally sharp and easily controlled for micrometry. It is not
even necessary to adjust the two spectra horizontally with the same
care as when no slit is used, but the vertical coincidence of spectrum
lines must be sharp. Naturally the use of the slit has one draw-
back, as the resolving power of the grating is decreased and the
spectrum lines are only just visible. The adjustment, however, may
be made before the slit is added. A few examples may be given.
For a slit i mm. wide over the telescope or collimator, only the
immediate edges at the crack S, about .5 mm. each in breadth, are
active. A narrow range of large fringes are seen in the field easily
controlled by the micrometer screw. With a slit 3 mm. in width
the lower limit is much increased the upper diminished, to a size
of about 3 inches per fringe. In the absence of the slit the field is
free from fringes. \\'ith a slit 6 mm. wide, the upper limit is again
decreased the lower much increased ; nevertheless the finest fringes
appear only after the slit is removed. Using double slits over the
collimator, each i mm. wide and 3 mm. apart, fringes of medium
size limited at both ends appear; 3 mm. slits 6 mm. apart show only
the very fine fringes, but both sizes are still limited. Finally when
all but about .5 mm. of the edge of the crack of the grating g' is

132 BARUS— ELLIPTIC INTERFERENCE [April 21,

screened off, whereas the whole grating g (about one half inch
square) is without a screen, all the fringes from the maximum size
to complete evanescence beyond the range of visibility are pro-
ducible. Naturally if the edge of g' is quite dark everything
vanishes.

It follows therefore that pairs of corresponding rays are always
in question. These corresponding rays are at a definite ND, apart
where D is the grating space and A^ the number of lines per cm. of
the grating in question. This distance ND is greater as the fringes
are smaller and may be of the order of a cm. when the fringes pass
beyond the range of visibility. Again ND is equal to the width of
the crack when the largest fringes vanish. Finally when ND is
zero, as in the original unbroken grating, the size of the fringes is
infinite.

It has been stated that the use of the slit or a laterally limited
objective is advantageous because all the lines are much sharper.
Inert or harmful illumination is cut off. If the slit is over the
objective of the telescope only a small part of the field of view shows
the lines; if placed over the objective of the collimator, the fringes
are of extreme clearness throughout the spectrum. It may be ulti-
mately of advantage to use the edge near the crack g' only, together
with the whole of g. For if a small strip of g' at the crack 5" is
used with the whole of g, the smaller fringes are weakened or wiped
out. Thus the inner edge of the nearer grating with successive
parts of the further grating is chiefly effective in the production of
these interferences.

To bring the two edges quite together was not possible in my
work, as they were rough and the apparatus improvised.

7. Data. — Some measurements were attempted, with the view
only of checking the equations presently to be deduced. The adjust-
ment on an ordinary spectrometer is not firm enough and the fringes
being very fine (a few minutes of arc) are difficult to follow unless
quite stationary.

Table I., however, gives both the values of de/dn, displacement
per fringe, for different angles of incidence i and of diffraction 6,
and dO/dii, the angular deviation per fringe at the D line. In meas-

igii.]

WITH REFLECTING GRATING.

133

uring the latter it was necessary to count the fringes between the
C and D lines and divide their angular distance apart by these num-
bers. As c cannot be measured, its successive increments Ae from
the first position are given. These are presently to be associated
with the corresponding increments of dn/dO.

TABLE I.

Values of dO/dn. etc. t' = 53° 15'. 7? = 200 X 10"" cm.

Observed.

Computed.

Fringes.

, e and 6'

ddldn

dn\d6

t>.dn\d9

A^

Cidnlde

At 9'
Adnlde

Mean
Ad/ijde

Region.

120

75

90
71

55
36

24
41

30° 27^

28° 14'

Diff

2° ly

29° 09'
28° 14'

Diff

55'

30° 27'

29° 43'
Diff.

44'

1/ 17//
1^46'^

46''

I' a/'

3080-1
1950/

4438-1
3438/
2250

1875 \
3203/

1 130

1000

II88

1328

.025

.025
.050
•075

.025

1260

II16
1259

1028

1027
1 196

1 140

1072
1228

Between C
and jD lines

Near C line
Near D line

8. Equations. — In Fig. 5, L and L' represent a pair of corre-
sponding white rays, reflected into R and R' and diffracted into D
and D' at angles i and 6. respectively. The half gratings g and g'
are separated along the crack S\ and g' is movable parallel to itself
by a micrometer screw normal to g'. Let the normal distance apart
of the gratings be c. The incident rays L, L' strike the originally
coplanar grating at points A' rulings apart, or XD cm. apart, if D
is the grating space. In the separated grating let these points be at
a distance c apart. Let d be the incident wave front and /; the corre-
sponding dift'racted wave front and call the angle between r and d. y.

When there is reinforcement the path dift"erence of the rays L
and L' from the incident (d ) to the dift'racted (/;) wave front, may
be written ;;A ^= b — a.

where b and a are the distances of /; and d from the points of inci-
dence of L and L' on the grating g and g' respectively. If finally /

134

BARUS— ELLIPTIC INTERFERENCE

[April 21,

is the length of the prolongation of L' between the gratings we may

write in succession

(i) d = NDcosi

(2) f=^cseci,

( 3 ) o = ND sin / — c sec i,

(4) tany = a/d,

(5) C^=ND cost sec y,

(6) b = csm(i^e — y).

Fk;. 5. Diagram.

cr

To these should be added

(7) dN/dc = t2ini/D.

Hence after removing y and arranging

nX = A^D {cos i sin (/ + 0) — sin / cos ( i -{- 0) — sin i]

-\- csec i{i -\- cos {i -\- 6) ),
which reduces to

or smce

iK^^ND (sin 9 — sin /) -\-eseci(i + cos (i^6)),

sin ■/ — sin ^ = X/D,

191 i.l WITH REFLECTING GRATING. 135

finally

(8) („ + X)X = . i±i5li^ Jtl) = ^-^cos^i + 0)l2

^ ^ COS t COS z

This must therefore be regarded as the fundamental equation of the
phenomenon. Equation (7), however, leads on integration to

(9) N = et2ini/D-]-N,,
where N^^D is the width of the crack.

If the value of A^ from (9) is put into (8) together with the
equivalent of X/D, it appears after reduction that

(;/ -f iVJX, = ^-(005 / -f cos 6) = 2e cos cos .

The case of A^ = o, ^ > o would correspond to the equation

(10) h\ = e[i -\- cos (/ -f- 6)] I cos i = 2€ cos^ / cos i,

which is onl}- a part of the complete equation (8). For i^O,
one active half, kh, is necessarily partly behind the other half, k'h',
and therefore not adapted to bring out the phenomenon as explained,
unless c = o.

9. Differential Equations. Displaccinoit per Fringe, de/dn. —
To test equation (8) or (10) increments must be compared. The
latter gives at once since A" is constant relative to e like /, 6, and A,

de \ X

('■) 7° .^ ■= ITe^^^9

ail cos / + cos V 2 cos cos

2 2

which is the interferometer equation when the fringes pass a given
spectrum line, like either D line, wdiich is sharp and stationary in the
field. Equations (7) and (11), moreover, give after reduction

i-e

( 1 2) dNjdn = tan / tan .

Table I. contains values of de/dn computed from (11), made under
widely different conditions (i^6, i<.6, first and second order).
The agreement is as good as the small fringes and the difficulty of
getting the grating normal to the micrometer screw in my impro-

136 BARUS— ELLIPTIC INTERFERENCE [April 21,

vised apparatus admit. If this adjustment is not perfect A^'q changes
with c. From equation (12), moreover,

dN

dN dd

dh\de dN^

dn ~

' dd dn ~

dS dn ~ dn '

(12')

since A'^o is constant only relative to e when 6 varies.

10. Deviation per Fringe, etc., dO/dn, dO/de. — These measure-
ments are still more difficult in the absence of special apparatus,
since e is not determinable and the counting of fine flickering fringes
is unsatisfactory ; but the order of results may be corroborated by
observing the numljer of fringes between two Fraunhofer lines, like
the C, D and other lines used. Differentiating equations (8) and
(10) for variable n, A, 6, and N (since dN/dO is equal to dN^/dO,
equation (12')) and inserting — D cos 6- dd/dn=dX/dn, it follows
after arranging that

(13)

dO X- I + dNjdn

dn eD i + cos {i + ^) eD cos /(cos i + cos &)

or

dO X 1-6

.tan

dn e cos / 2 '

Combining this with (11)

dd \ sin / — sin 6

^ ' dn eD cos / e cos /

Since, in equation (13), e is not determinable it is necessary to com-
pare increments Adn/dO in terms of the corresponding increments
A^, whence

(15) A{dn/dO) = ( cos // X tan ^-^ j A^'.

Table I. also contains data of this kind com[)uted separately for the
Fraunhofer D, C, etc., employed and their mean values. To find
the mean width of fringes between these lines, their angular devia-
tions were divided by the number of fringes counted between them
at different values of e. The results agree as closely as the difficulty
of the observations warrants. One mav note that without remov-

I9II.] WITH REFLECTING GRATING. 137

ing X, the corresponding coefficients would be i\d(n -{- N)/d$, and
these are much more in error, here and in the preceding cases. If
from d9/dn, e is ehminated in terms of {n -\- N ) the equation is

dd \ ' I
(i6)

dn D{n + N^cosi'

so that for a given vahie of i, 6, jVq, they decrease in size with n.
If ;/=o they reach the hmiting size

dd \

dn DN^ cos / '

If the crack N ^JJ should be made infinitely small, they would be
infinitely large. To pass through infinity, A'^ must be negative,
which has no meaning for i > ^ or would place one eft'ective edge of
the crack 5" behind the other. These inferences agree with the
observations as above detailed. If, however, i <^ 0, a. negative value
of Nq restores equation (i6) for //:^o to equation (17), as was
actually observed (Figs. 2 and 3).

Finally equation (14) might be used for observation in the incre-
mented form

. „ D cos i
(17) A{de/de) = ^^^Ae;

but I did not succeed with it. One loses track of the run of a
fringe w^ith de.

II. Colored Slit Images and Disc Colors of Coronas. — In the
above experiment the fringes were but a few minutes apart. It is
obvious, however, that if A''^ is sufficiently small the fringes will grow
with decreasing 11, in angular magnitude, until there are but a few
black bands in the spectrum. Under these circumstances the unde-
viated image of the superimposed slits must appear colored, particu-
larly so if an effect equivalent to A^^, is present throughout the
grating. This phenomenon of colored slits is apparently of interest
in its bearing on the theory of coronas, where there is also an inter-
ference phenomenon superimposed upon a diffraction phenomenon,
as is evidenced by the brilliant disc colors. For instance suppose

138 BARUS— ELLIPTIC INTERFERENCE. [April 21.

a corona were produced by a sufficient number of fog particles dis-
tributed throughout a plane normal to the undeviated rays. Now
let the alternate particles be moved in the same way slightly to the
rear of their original position and let the distance between the two
planes be small relatively to the wave length of light. In such a
case there should be two identical coronas, superimposed in all their
parts and they should therefore interfere. Inasmuch, however, as
even small fog particles are of the order of size of .0001 cm. and
their mean distance apart fifty times larger, i. e., .005 cm., it remains
to be proved whether such an effect can be looked to as an explana-
tion of the disc colors of coronas.

Brown University,
Providence, R. I.

ON THE TOTALITY OF THE SUBSTITUTIONS ON n

LETTERS WHICH ARE COMMUTATIVE WITH

EVERY SUBSTITUTION OF A GIVEN

GROUP ON THE SAME LETTERS.

By G. a. miller.

(Read April 20, 191 1.)

§ I. Introduction.

The problem to determine all the substitutions on n letters which
are commutative with every substitution of a regular group on the
same letters was first solved explicitly by Jordan in his thesis. It
was found that with every regular group there is associated a group
which is conjugate with this regular group, such that each is com-
posed of all the substitutions which are commutative with every
substitution of the other. ^ These two regular groups were called
conjoints by Jordan and it is evident that they have a common
holomorph and that their group of isomorphisms is the quotient
group of this holomorph with respect to either of these two regular
groups.

The more general problem to determine all the substitutions on
n letters which are commutative with every substitution of any
transitive group on the same letters seems to have been solved for
the first time by Kuhn in his thesis.- He found that with each
transitive group G of degree n there is associated a group K on the
same n letters which is composed of regular substitutions on these
n letters, in addition to the identity. The order of K is a, the degree
of the subgroup composed of all the substitutions of G which omit a
given letter being n — a. Hence a necessary and sufficient condi-
tion that K be transitive is that G be regular, and the number of the
systems of intransitivity of K is always equal to n/a. When a <i n
K is formed by establishing a simple isomorphism between n/a

^Jordan, thesis, Paris, i860, p. 39.

"Kuhn, American Journal of Mathematics, Vol. 26, 1904, p. 67.

139

140 MILLER— SUBSTITUTIONS OX Ji LETTERS. [April 20,

regular groups, each of these regular constituent groups being trans-
formed into every other under G. In particular, the degrees of these
separate regular groups are systems of imprimitivity of G.

While K is composed of all the substitutions on these letters
which are commutative with every substitution of G it is not
generally true that G is also composed of all the substitutions which
are commutative with every substitution of K and involve only the
letters of K. It is evident that a necessary and sufficient condition
that such reciprocal relations should exist between G and A' is that
G involves as an invariant subgroup the direct product of n/a
regular groups, and that the remaining substitutions of G permute
these regular groups according to the symmetric group of degree
n/a. The order of G must therefore be

a'' • k!, where k^n/a.

Hence the theorem : A necessary and sufficient conditio)i that a tran-
sitive group G of degree 11 ini'oli'e all the substitutious on these n
letters zvhich arc commutative zvith every substitution of the group
K composed of all the substitutions on these n letters zvhich are
coiumitative with e-c'cry substitution of G, is that the order of G be
a^ ■ k!, zvhcre the degree of the subgroup of G which is composed
of all its substitutions which omit a giicn letter is n — a and
k = n/a.

When G does not include all the substitutions which are commu-
tative with every substitution of K it is clearly a subgroup of the
group formed by such substitutions. Hence we have the theorem :
// a transitive group of degree n is such tliat a subgroup composed
of all its substitutions which omit a given letter is of degree n — a
the order of this transitive group must divide a^ • k !, where k ^n/a.
To illustrate this theorem as well as the theorem of the preceding
paragraph we may use for G the group of the square represented as
a substitution group on four letters. In this case a = 2, k = 2,
and the order of G is exactly a'' ■ k! Moreover, K is of order 2, and
of degree 4, and G includes all the substitutions on these four letters
which are commutative with every substitution of K, so that G and
K are so related that each is composed of all the substitutions on

19".] MILLER— SUBSTITUTIONS OX n LETTERS. 141

these letters which are commutative with every substitution of the
other. A necessary and sufficient condition that K he a. subgroup of
G, when G and K are so related that each is composed of all the
substitutions on these letters which are commutative with every
substitution of the other, is that K be abelian. ^^'hen G and K are
both abelian they must be regular and identical.

It may be of interest to consider several of the special cases of
the general theorems expressed above. \\'hen a^i. K is the
identity. That is. if the subgroup, composed of all the substitutions
which omit a given letter of a transitive group of degree n, is of
degree ;/ • — ■ i the identity is the only substitution on these n letters
which is commutative with every substitution of this transitive
group, and the order of this group divides n! In the other extreme
case, when a = n, the given theorems include the main known
results as regards the substitutions which are commutative with
every substitution of a regular group. As the term conjoints has an
established meaning as regards regular groups it seems undesirable
to use this term with the more general meaning that each of two
substitutions groups of degree »/ is composed of all the substitutions
on these 7i letters which are commutative with every substitution
of the other. We shall therefore call such groups amicable, using a
term of Greek number theory. Hence we may say that a necessary
and sufficient condition that a transitive group of degree )i is one of
a pair of amicable groups is that its order be a.'^' • k!, n — a being
the degree of one of its subgroups composed of all its substitutions
which omit a given letter, and k = n/a. This proves also incident-
ally that ;; is always divisible by a.

From the preceding results it is easy to deduce a theorem as
regards the total number of the transitive groups of degree n which
belong to pairs of amicable groups. In fact, since K is composed of
simply isomorphic regular groups the number of the distinct possible
groups K is ecjual to the number of the dififerent abstract groups of
order a, two substitution groups being regarded as distinct only
when it is not possible to transform one into the other. As G is
completely determined by K there results the following theorem :
TJic niinihcr of the distinct transitirc groups of degree n zvhicJi

142 MILLER— SUBSTITUTIONS ON n LETTERS. [April 20,

belong to pairs of amicable (/roups is equal to the sum of the
numbers of the abstract groups ivhose orders are divisors of n,
including n and unity amoig these divisors.

§ 2. Amicable Intransitive Groups.

In the preceding section it was observed that a necessary and
sufficient condition that each of two amicable groups be transitive is
that they be regular, and that if a non-regular transitive group
belongs to a pair of amicable groups the second group of the pair
is intransitive. It remains to consider the case when each one of a
pair of amicable groups is intransitive. An infinite system of such
groups may be constructed by establishing a simple isomorphism
between n symmetric groups of degree n, n > 2, and determining the
totality of the substitutions which are commutative with every sub-
stitution of the intransitive group G thus formed. It is evident that
this totality of substitutions constitutes a group K which is similar to
G. That is, G and K are two conjugate intransitive substitution
groups each being composed of all the substitutions on these w^
letters which are commutative with every substitution of the other.

The existence of the two amicable intransitive groups G and K
of the preceding paragraph may also be established as follows :
Consider the n~ ;n-sets^ of the symmetric group of degree n as
regards the symmetric group of degree n — i. On multiplying these
n- 7;i-sets on the right by all the substitutions of this symmetric
group the n- ni-sets are permuted according to a group G' similar to
G, and by multiplying them on the left they are permuted according
to a similar group K'. From the fact that multiplication is associa-
tive it results that every substitutiDu of G' is commutative with every
substitution of K'. Moreover as every substitution on these n- letters
which is commutative with every substitution of G' must permute
some of its systems, it is evident that K' is composed of all the
substitutions on these letters which are commutative with every
substitution of G', and vice versa; that is, G' and K' are in fact two
amicable intransitive groups for every value of ;/. The group

^ If H is any subgroup of a group G, the total numlier of distinct sets of
operators of the form S^HSp. where Sa and 5"^ are operators of C, are known
as the })i sets of G as regard.? H.

191 1.] MILLER— SUBSTITUTIONS ON n LETTERS. 143

generated by G' and K' is clearly imprimitive and of order {n!)-.

The existence of amicable intransitive groups which are not
included in the preceding infinite system can be easily proved by the
following examples : Let G be the dihedral group of order 8 and H
any one of its non-invariant subgroups of order 2. With respect to
H there are 8 w-sets of G since H is transformed into itself by 4 of
the operators of G. Hence these eight 7H-sets are permuted accord-
ing to a group which is simply isomorphic with G and has two
transitive constituents both by right and also by left multiplication.
Each of the two substitution groups obtained in this way is clearly
composed of all the substitutions on these eight letters which are
commutative with every substitution of the other and hence these
are two amicable intransitive groups whose transitive constituents
are not symmetric.

The substitutions which are commutative with every substitution
of an intransitive group G either interchange systems of intransi-
tivity, or they are composed of constituents which are separately
commutative with the various transitive constituents of G. The
latter have been considered in the preceding section. Hence we
shall, for the present, confine our attention to those substitutions
which are commutative with every substitution of G and interchange
its systems of intransitivity. It is evident that these systems of
intransitivity are transformed by all the substitutions which are
commutative with every substitution of G according to a substitu-
tion group, and that those transitive constituents of G which are
transformed transitively among themselves must be simply isomor-
phic in G. These constituents are clearly transformed according to
a symmetric group by all the substitutions which are commutative
with every substitution of G. Hence the theorem: // an intransitk'e
group G is one of a pair of amicable intransitive groups, and if the
tratisitive coiistitiioifs of G are sncJi that no substitution on the
letters of the separate constituents is commutative zvith every sub-
stitution of the constituent, then must the consituents of G be
symmetric groups.

It is clear that G may have more than one set of transitive con-
stituents such that all those of a set are conjugate under the totality

144 ' MILLER— SUBSTITUTIOXS ON n LETTERS. [April 20,

of the substitutions K which are commutative with every substitu-
tion of G. In other words, the substitution group according to which
the transitive constituents of G are transformed may be intransitive.
When this condition is satisfied A' is the direct product of two or
more symmetric groups. This suggests a more general infinite
system of pairs of amicable intransitive groups than the one men-
tioned above : viz., Let G be the direct product of the p groups
formed by establishing simple isomorphisms between n^ symmetric
groups of degree n^, »„ symmetric groups of degree «„, •••, n
symmetric groups of degree ;/ (n^, n^, •••, n being distinct
numbers greater than 2), it is clear from what was proved
above that K is similar to G and hence G and K are ami-
cable intransitive groups. It should be observed that G and K
are akuays amicable zvhcncvcr tJicy arc siniilar but that the converse
of this theorem is not always true. This more general system of
amicable intransitive groups may clearly be constructed by forming
the direct product of the p symmetric groups of degrees Hj, jIo, •■-,
lip respectively and forming the ;n-sets as regards the subgroups H
obtained by forming the direct i)roduct of p symmetric groups of
degrees n, — i, n.-. — i, ••-, n — i respectively, one being taken
from each of the given symmetric groups, in order. If the /;;-sets
thus obtained are multiplied on the right and on the left by all the
operators of these sets there clearly results the two systems of
amicable intransitive groups in question.

To obtain a still more general infinite system of amicable intran-
sitive groups it should be first observed that the intransitive group
formed by establishing a simple isomorphism between in^ symmetric
groups of degree n^, written on m^ distinct sets of letters, is amicable
with the one obtained by establishing a simple isomorphism between
n^ symmetric groups of degree ;;?], written on n^ distinct sets of
letters, where ;/,, ui^ > 2. Hence it results that the direct product
formed by multi])lying p intransitive groups of degrees n^m^, tunu,
"'■> '^p '"p respectively, each being formed in the former of the two
ways mentioned above, is amicable with the direct product formed
by multiijlying the p groups of the same degrees respectively, but
constructed by establishing a simple isomorphism between n^ sym-

19II.] MILLER— SUBSTITUTIONS OX n LETTERS. 145

metric groups of degree ;//i, iu of degree uu, •••. n of degree iii^
respectively. ^Moreover, it results from the given theorem that these
direct products include all the possible sets of amicable groups in
which each of the two groups is intransitive and each of the transi-
tive constituents is not commutative with any substitution besides
the identity on the letters of the constituent.

The above therefore completes the determination of amicable
groups when both groups are intransitive, and the transitive constit-
uents are such as to involve subgroups whose degrees are just one
less than the degrees of the respective constituents. The cases in
which at least one of the two amicable groups is transitive were
considered in the introduction. It may be observed that whenever
an intransitive group is formed by establishing a simple isomorphism
between more than two symmetric groups it is one of a pair of
amicable groups. The second group is transitive when each of these
symmetric groups is of degree 2, wdien this condition is not satisfied
the second group is also a simple isomorphism between symmetric
groups. The group obtained by establishing a simple isomorphism
between two symmetric groups is evidently never one of a pair of
amicable groups unless the two symmetric groups are of order 2.
We may express this result in the form of a theorem as follows :
The intransitive group G formed by establishing a simple isomor-
pJiisui betzveen three or more synnnefrie groups, zvritten on distinct
sets of letters, is one of a pair of amicable groups, the second group
K being also such an intransitive group zvhenever the degree of the
given symmetric groups exceeds 2. The intransitive group formed
by establishing a simple isomorphism betzveen tzvo symmetric groups
is one of tzvo amicable groups only in the special case zchen these
symmetric groups are of degree 2.

By means of the given results it is not difficult to complete the
determination of all possible pairs of amicable intransitive groups.
Suppose that G is constructed by establishing a simple isomorphism
between any number of conjugate transitive groups written on dis-
tinct letters, each constituent being one of a pair of amicable groups.
If these constituents are not symmetric and not regular it is clear
that G is one of a pair of amicable groups and that the number of the

146 MILLER— SUBSTITUTIONS ON M LETTERS. [April 20.

transitive constituents of K is equal to the number of transitive con-
stituents in the amicable group corresponding to a transitive constit-
uent of G. Moreover, G is evidently not one of a pair of amicable
groups Mfhen its constituents do not have this property. Hence
there results the theorem : Tzvo necessary and sufficient conditions
that a given intransitive group be one of a pair of amicable groups
arc: i) that it be the direct product of transitive constituents zvhich
belong to pairs of amicable groups, or of sets of simply isomorphic
transitive constituents of this kind, or 2) that the number of simply
isomorphic constituents be greater than tzvo zvhenever they are
symmetric but not regular. From the Introduction it results that the
second group of this pair is also intransitive except in the case when
the intransitive group is composed of simply isomorphic regular
groups. It reduces to the identity whenever the given intransitive
group is the direct product of symmetric groups whose degrees
exceed 2. The pair of amicable groups are conjugate whenever one
is the direct product of regular groups, of sets of m simply isomor-
phic non-regular symmetric groups of degree n if the niz and w's
may be put into (1,1) correspondence such that the corresponding
pairs are equal, or of sets of m simply isomorphic non-symmetric
transitive groups of degree n (n — a being the degree of a subgroup
composed of all the substitutions of the constituent which omit a
letter) if the a's, m's and n/a's may be put into (1,1) correspon-
dence such that the corresponding triplets may be a, n/a, am for
every set of values a, m, n.

University of Illinois.

OBITUARY NOTICES
OF MEMBERS DECEASED

a*

i

HEXRY CHARLES LEA.

(Read January 20, 19 11.)
INTRODUCTORY REMARKS.

By WILUA^I \V. KEEN, ^I.D, LL.D,
President of the American Philosophical Society.

Members of the American Philosophical Society, ^Members and
Representatives of the Library Company of Philadelphia, of the Uni-
versity of Pennsylvania, of the Academy of Natural Sciences, and of
the Historical Society of Pennsylvania, Ladies and Gentlemen : —

In the days, of Julius Caesar and during the wars which followed
his assassination, "Triumvirate" was a word very familiar to
Roman citizens. But whether applied to the first or the second
triumvirate it had a sinister meaning. Our own city, however, for
many years has had an illustrious triumvirate of men who have been
eminent in literature, science and civic life. Horace Howard Furness,
S. Weir Mitchell and Henry Charles Lea. Xo other American city
could boast three names comparable to these.

When one of these three, and such a man as Henry Charles Lea
has passed away, it is fitting that his associates and the community
at large should halt for an hour in our busy life and pay a tribute
to his character and achievements.

The American Philosophical Society, of which he was an honored
member, therefore suggested to the four other public institutions
named with which Air. Lea was associated by membership, and
which had benefited by his active interest and generous support,
that a joint meeting in memory of Air. Lea should be held. The
idea was most cordially received and a speaker representing each of
these societies will share in the proceedings of the evening.

In addition to these distinguished local representatives. His
Excellency, the Right Lion. James Bryce, the British Ambassador,
has come from Washington especially to do honor to the memory
of his fellow historian and friend.

iv OBITUARY NOTICES OF MEMBERS DECEASED.

Through the generosity of Mr. Lea's family, two portraits, one
of Mr. Henry C. Lea, and the other of his father, Mr. Isaac Lea,
will be presented to the American Philosophical Society.

As an illustration of the thoroughness with which Air. Lea pre-
pared for his work, I may cite the following little incident :

While spending the winter of 1907-8 in Rome I saw in an anti-
quarian bookstore a catalogue of books on Witchcraft, a subject in
which I knew Mr. Lea was deeply interested and of which, though
he was then eighty-three years old, he contemplated writing a full
account. I sent the catalogue to him — a list of seventy or eighty
titles — some of them very rare, and offered to aid him in securing
any which he might wish to purchase. In reply I received a letter
of thanks, but he declined my proffered assistance for the very
good reason that he "already had all of them in his library."

I have now the pleasure of introducing Edward P. Cheyney,
Professor of European history in the Llniversity of Pennsylvania,
and a co-worker with Mr. Lea, who will read a memoir on the Life
and Works of Mr. Lea.

ON THE LIFE AND WORKS OF HENRY CHARLES LEA.
By EDWARD POTTS CHEYXEY.

It has been so short a time since Mr. Lea was moving among us —
to so many of those who are here he is still almost a living pres-
ence— that it is well-nigh impossible to view his long life and to esti-
mate his great work as a thing detached from us, completed, a part of
the past. Especially may one who through his whole mature life has
looked upon ^Nlr. Lea with admiration as a scholar, with gratitude as
a kindly adviser, critic and friend, and with constantly increasing
appreciation as one of the world's • great men, acknowledge the
inadequacy of this sketch of his life and list of his achievements.
Indeed in this city, in which ]\Ir. Lea's whole life was passed, and in
this company to whom his personality and much of his work were
familiar, I shall frequently rather be bringing his career to remem-
brance than giving information concerning it.

Henry Charles Lea was born in Eighth Street above Spruce,
Philadelphia, in the year 1825. His boyhood has left a few sugges-
tive reminiscences. He remembered learning the letters of the Greek
alphabet as a child of six at the bedside of a mother well-educated
and strong in mind, however frail in body — the daughter of INIathew
Carey, the sister of Henry C. Carey. The intellectual atmosphere
into which he was born and in which he grew up is indicated also
by the studies in natural history of his father, Isaac Lea, and by his
own training under a private tutor. From this tutor, whose name
was Eugenius Nulty, a scholar of an old and rigorous type, and a
man of much individuality and force, he received an unusually thor-
ough and effective drill in the ancient languages and other funda-
mentals. A short stay in 1832 at a school in Paris, where he was
the only boy not a native of France, probably had something to do
with his easy use of Erench, both as a spoken and a written language,
during his later life. He remembered the French boys bringing to
school bullets found in the streets after the Parisian rising that led

vi OBITUARY NOTICES OF MEMBERS DECEASED.

to the dethronement of Charles X. It was a long memory that
covered the history of France from the Bourbons to the thirty-
eighth anniversary of the Third Republic.

A more characteristic reminiscence was that of his desire, as a
boy of twelve or fourteen, for a copy of x^nacreon in the Greek,
which was unobtainable because of the necessity, in the shadow of
the crisis of 1837, of so rigid an economy as to forbid the expendi-
ture of fifteen cents for the cheapest copy procurable. In a series of
visits to the Philadelphia Library he copied the whole of Anacreon,
and thus possessed himself of the first of his collection of manu-
scripts— none the less accurate probably because it was made in the
nineteenth and not in the ninth century. The publication in Silli-
mail's Journal when he was a boy of thirteen of a paper on
" Manganese and its Salts," the result of a period of study in a
chemical laboratory, may serve as a reminder that his earliest training
was as much in scientific as in classical lines ; and also that his mind
was of that type that must produce as well as ac(|uire.

By 1843 boyhood was over. At the age of eighteen, a new period
opened with his entrance into his father's publishing house, and thus
commenced a business career which was to last for thirty-seven
years, till his retirement in 1880. As a youth, during the next four
years, he worked hard at business in the daytime and equally hard
at his studies late at night and early in the morning. Few persons,
I think, can look over the files of the magazines of the years from
1843 to 1846 and realize without astonishment that the sixteen or
more long articles signed by Henry C. Lea were the work of a young
business man of eighteen to twenty-one, regularly occupied during
the long working hoiu-s of that period. He was fulfilling two
apprenticeships at the same time, one to the publishing business, the
other to literature.

It is curious to see the conflict of interests in the latter of these
fields between science and the humanities. In May, 1843, ^^^
iniblished in the Transactions of flic American Philosophical Society
a paper on " Some New Shells from Petersburg, \'a.," and in August
of the same year in The Knickerbocker of New York an article on
" Greek Fpitaphs and Inscriptions." In September, i8z^4, in a
southern journal is to be found a critical article by him on Leigh

HENRY CHARLES LEA. vii

Hunt ; two months later in a journal of natural history, a description
of '' Certain New Species of Marine Shells." But the literary
gradually predominated over the scientific. In the Southern Literary
Messenger of Richmond, \'a., in the year 1845 and early in 1846, he
published a series of six articles under the general heading " Remarks
on Various Late Poets." These are critical studies and appreciations
of Miss Barrett, long before she became Mrs. Browning; of ]\Iiss
Landon, while she was still disguised under the initials L. E. L. ;
of Tennyson, then publishing his earlier poems ; of Eliza Cook,
and several others. Interspersed with these in the same and other
journals, are reviews and articles with many quotations and transla-
tions on " The Greek Symposium and its ^Materials," " Anacreon,"
" The Imagination and Fancy of Leigh Hunt," the Latin poet
" Festus," and " Menage," the poet of the French renaissance.

To such activity there is usually but one end, and to Mr. Lea it
came in the year 1847, ^vhen a very serious breakdown in his health
put an end for a while to all efforts except those for its restoration.
Recuperation, travel, marriage, hard and well-remunerated mercan-
tile work, rather than studv and writing, filled in the remaining
years of early manhood.

With improving health and increasing strength began what may
be considered a third period, marked by many activities, including
a resumption of written work, which had now been laid aside for
more than ten years. In the North American Rcvieiv of January,
1859, appeared what was ostensibly a review by Mr. Lea of a
volume published by a German historian some years before. But
the article was really not so much a review as a scholarly study
of two forms of mediaeval trial, compurgation and the wager of
battle. An article on judicial ordeals appeared six months later,
also in the form of a book review. These studies, revised and
enlarged and with an additional chapter on torture as a form of
trial, were gathered into a volume and issued in 1866 under the title
" Superstition and Force." This was ^Ir. Lea's first book. Others
followed on similar subjects. In 1867 appeared "The History of
Sacerdotal Celibacy," and in 1869 " Studies in Church History."
These works it will be observed are in a totally different field from
that of his early literary and scientific writing. His entrance upon it

viii OBITUARY NOTICES OF MEMBERS DECEASED.

seems to have been by the following route. In the desultory reading
of his long period of ill health, he had taken up the French memoir
writers and chroniclers. Following the bent of a naturally logical
mind he had traced these writers backward in time from Commines
to Monstrelet, from Froissart to the Chronicjues de St. Denis and
Villehardouin, till, in the Middle Ages, he had found himself in a
new world, faced and surrounded by the conceptions of mediaeval
law and the mediaeval church. Once having become interested in
this body of institutions he was more and more impressed with its
significance; he perceived the influence of mediaeval jurisprudence
and the mediaeval church on modern times ; and to this phase of
the history of civilization he devoted the studies of the remainder
of his life.

But Mr. Lea's studies were still only one of his interests. He
was deeply moved by the questions raised by the Civil War and took
an active part in the work of their solution. His labors in the
national cause as well as those in the cause of municipal and civil
service reform I must leave to rpore competent hands for descrip-
tion. I may, however, refer to his characteristic recourse to his pen
to reach his objects. During the height of the dispute concerning
slavery, when Bishop Hopkins's pamphlet, the " Bible View of
Slavery," was issued and widely circulated as a defence of that insti-
tution on Biblical grounds, jNIr. Lea wrote a parody, the " Bible View
of Polygamy," showing that just as good a case might be made out
from the Bible for the one institution as the other. Later, as a
warning in our treatment of the American Indians, he wrote an
article on the " Indian Policy of Spain," and on the outbreak of the
Spanish war he published an article in the Atlantic Monthly of July,
1908, suggesting the deep-lying causes of the decadence of Spain.
When we took up new responsibilities in the Philippines, he pub-
lished a pamphlet called " The Dead Hand," utilizing the experience
of Catholic governments to show the evils of the possession of land
by ecclesiastical bodies. These are only a few examples of much
more than a score of pamphlets, articles and open letters called forth
by public crises in wdiich Mr. Lea took a keen interest and to the
solution of which he always felt that history had something to
contribute.

HENRY CHARLES LEA. ix

His services in connection with tlie adoption of the first Inter-
national Copyright Act had the special value that he was both an
author and a publisher, and could look on the subject from two
points of view. The first of his two long periods of service on the
Board of Directors of the Philadelphia Library began early in this
period, closing in 1879.

Before passing on to the characteristics of a later period it must
be noted that it was during this part of his life that ^Ir. Lea laid the
foundation of his library. So far as I am aware Air. Lea stands
alone among historical scholars in having done his work entirely in
his own library, without recourse to any university or public collec-
tion , and this library was entirely his own creation. He had no
nucleus for it, no aid in constructing it. No one who has evei
entered upon the serious study of a new field will fail to estimate
at something like its true value the difficulty of finding what
materials for its study exist, and of obtaining access to them.
In Mr. Lea's subject these difficulties existed in the highest de-
gree. Few bibliographical guides then existed, no older or even
contemporary scholar was at hand to give advice ; his ideals of
thoroughness were so uncompromising, and his desire for knowl-
edge of the actualities of the past was so keen, that the merely
obvious sources of information were quite inadequate to his desires.
Much that he did was pioneer work, in which equipment must be
constantly adjusted to newly discovered needs. Fortunately he had
means which enabled him to purchase books freely wherever they
might be found, and when the materials needed proved to exist only
in a manuscript form, to have special copies of those made for his
use. But the purchase price bears no very close relation to the value
of a library collected with care, insight, discrimination, years of labor
and watchfulness, and above all a constant realization of its character
as an instrument adapted to a certain specific end. I may perhaps
be pardoned if I say that Mr. Lea's bequest of his library to the
University of Pennsylvania instead of either burying it in a great
public collection, or allowing it to remain a purely private possession,
or scattering it to the four winds, seems to me to place in additional
clearness his conception of it as a working collection for purposes of

X OBITUARY NOTICES OF MEMBERS DECEASED.

research, to serve others in the future for the use to which he him-
self put it.

In 1865 Mr. Lea anticipated withdrawing from active business
hfe, but the sudden death of his partner seemed to necessitate his
remaining in control, and he continued a publisher for fifteen years
more, until 1880, when he retired. This change was coincident
with or shortly followed by a second breakdown, which made him
almost an invalid for four years from 1880 to 1884. During this
time his restlessly active mind could not refrain entirely from pro-
duction, and he returned, for the moment at least, to the more purely
literary interests of his earlier life. He had always been fond of
making translations from various languages into English, and in his
historical as well as his literary articles he had frequently given
reproductions of old poems. He had also written verse from time to
time, and occasionally exchanged such productions with at least one
other well-known business man in Philadelphia. The war especially
had led him to write several poems. Some forty of these, mostly
translations from French, German, Italian, Spanish, Latin and
Greek, he gathered together and published privately in 1882 under
the title "Translations an<l other Rhymes." Whether from Mr.
Lea's temperament, mood or physical condition, these poems look
rather to the darker sides of life, its experiences and mysteries; as
in his own verses closing

The riddle wlio can read?

Who guess the reason why?
We know luit tliis indeed.

We are liorn, we grieve, we die.

With ]\Ir. Lea's return to his usual health in 1884 began a long""
period, twenty-five years, of vigorous, laborious and yet serene life;
old age it could hardly be called, although it carried him from his
sixtieth year through his eighty-fou.rth. llie many-sided interests
of this period of life and activity, I can scarcely do more than name.
A large fortune, watched over assiduously, and with very definite
theories as to its investment and use; scarcely less well-marked
abstention from certain forms of investment ; an unwillingness to
serve on res]:)(Misil)lc boards without ])erforming the labor required
by responsibility; discriminating and carefully considered philan-

HEXRY CHARLES LEA. xi

thropic and charitable gifts — such were some of his most material
interests. He gave quietly, and only after the object had fully com-
mended itself to him. Such giving can hardly be described in detail
and must be left in the main to the privacy of purely personal life.
A few of the more notable of these benefactions, however, may be
mentioned. In 1888 Mr. Lea erected an addition to the Philadelphia
Library building, doubling the size of its reading rooms and book-
stacks. In 1897 he erected important buildings for the Pennsyl-
vania Epileptic Hospital and Colony Farm at Oakbourne, Pa., and
subsequently paid for the erection of still other buildings, added to
the endowment of the institution and contributed toward its main-
tenance. In 1889 he oiTered to pay for the construction of a building
for the study and teaching of hygiene and bacteriolog}- at the L'ni-
versity. This building was erected in 1891 and dedicated February,
1892. His library, as is well known, he bequeathed to the Univer-
sity. In addition to these and other substantial gifts to the Univer-
sity Air. Lea was one of that body of generous subscribers to its
general expenses who have enabled it, without the large endowments
of the other great Eastern universities, and without the munificent
state appropriations of those in the West, to perform a work fully
commensurate with theirs. For a number of years he subscribed
liberally to this purpose and lightened the burden of the Provost by
the kindness and readiness with which he gave.

Immersed in his literary work and devoting many hours a day
to it, yet the courteous host of the Wistar parties, the cordial giver
of time and advice to any who were preparing to entertain learned
bodies in Philadelphia, the participant in all scholarly projects in
the field of history, the ready writer of communications to the public
journals on all large questions that arose, the persistent walker
through Philadelphia streets, he was certainly not a recluse. His
face and form were familiar to a large circle of acquaintances and
he welcomed callers cordially. Among his more intimate character-
istics during his later life may be mentioned his habit of spending
some days or weeks each year at the Delaware Water Gap, in the
spring when the fruit trees blossomed, and in the fall when the
autumn leaves were in their glory. He was always interested in
wild flowers, knew them and their haunts in the countrv and at the

xii OBITUARY NOTICES OF MEMBERS DECEASED.

shore, where he spent the summer, and he even botanized among
the flower stands of the old colored women along Market Street.
He was fond of curios and semi-precious stones, attended Philadel-
phia sales and corresponded with dealers in such objects, and made
an extensive collection of Japanese pottery and bronzes. He col-
lected also engravings and books on art.

But it was primarily to the work of the historian that the labors
of Air. Lea were devoted during this long period of his later life;
and it was as a scholarly historian that he won eminence and received
recognition in full measure. Doctoral degrees from Giessen, Pennsyl-
vania, Harvard and Princeton ; fellowships or honorary or associate
membership in more than thirty learned societies in Germany, Italy,
Russia, England, Scotland and America; medals, congratulatory
letters and private correspondence testify to this. He was long a
Vice-president of the Historical Society of Pennsylvania. He was
urged to serve as President of the American Historical Association
soon after its organization, and finally consented in 1903. He could
not preside, as its meeting was held that year in New Orleans, and
he did not feel that he could make so long a journey from home, but
his presidential address on " Ethical Values in History" made a pro-
found impression at the time and was reprinted afterward.

These honors and this recognition were partly for his earlier work
on the history of mediaeval law, already described, but in the main an
acknowledgment of the series of great works which during this
period appeared in almost unbroken continuity. In 1888 appeared
the " History of the Inquisition of the Middle Ages," in three vol-
umes; two years afterward a volume of "Chapters from the Relig-
ious History of Spain Connected with the Inquisition " ; two years
after this he edited a "Formulary of the Papal Penitentiary"; in
1896 he published his " History of Auricular Confession and Indul-
gences," in three volumes. Then came a period of ten years in which
only one volume, the " Moriscos of Spain," and some pamphlets and
magazine articles were published. This long passage of time was
due to the fact that he was preparing his largest and most important
work, a " History of the Inquisition of Spain," published in four
volumes in 1906 and 1907. In 1908 he published a " History of the
Inquisition in the Spanish Dependencies," and was at work last year

HENRY CHARLES LEA. xiii

collecting material and making notes for a " History of Witch-
craft," when he finally laid down his pen.

The late period of life to which this productivity extended is of
much significance. Few historians have died under sixty ; much
historical writing has been done by men in their seventies ; Ranke
and Bancroft at ninety, Mommsen at eighty-six, and ]\Ir. Lea at
eighty-four are only some of the most conspicuous instances of
a considerable number of scholars who with unclouded clearness
of mind and unabated vigor of spirit were drawing on their long-
accumulated store of knowledge and applying their slowly ripened
judgment to the problems of history at more than eighty years
of age.

The early part of Mr. Lea's life was contemporaneous with the
beginnings of American historical production. The historical works
of Irving, " Columbus " and the " Conquest of Granada," were pub-
lished during Air. Lea's earliest years. In 1834 appeared the first
volume of Bancroft's " History of the United States." In 1837
Prescott began his historical career by the publication of " Ferdi-
nand and Isabella." Parkman's first work, the " Conspiracy of
Pontiac," was published in 1851, and the first volume of Motley's
" Rise of the Dutch Republic " in 1856, when Air. Lea was collecting
material for his " Superstition and Force."

A marked difference, however, is to be noted between the his-
torical work of these writers and that of Air. Lea. Each of the five
chose as a subject a period of time or a series of events or a group
of personalities which possessed some well-defined dramatic char-
acter. The almost personal struggle, gigantic in significance, how-
ever limited in time and space, fought out in the Netherlands between
William of Orange and Philip of Spain, awakened the sympathetic
fire and was described by the literary grace of Alotley. The ro-
mantic adventures of Cortez and Pizarro, and the scarcely less
stirring narrative of events in Spain during the same period gave a
subject of unexcelled interest to Prescott. Parkman from boy-
hood was attracted, as he tells us, by the picturesque surroundings
and incidents of the struggle for the Northern continent between
the Indian, the Frenchman and the Englishman. Bancroft selected
the early and heroic period of our own national life, and Irving

b*

xiv OBITUARY NOTICES OF MEMBERS DECEASED.

equally dramatic episodes. In contrast with these Mr. Lea chose a
much earlier period of the world's history and a group of subjects
during that period of which the elements are less emotional, more
intellectual ; in which the problem is rather to understand than to
depict, rather to explain than to narrate. Whereas their periods
were modern, he chose the middle ages ; whereas they recounted
principally events, he wrote principally on institutions. The medi-
aeval conceptions of law ; the organization, ideals, doctrines and prac-
tices of the mediaeval church ; the origin, development, connections
and influence of the Inquisition, one of the most characteristic
embodiments of the spirit of the mediaeval church — such were the
great problems he took up for solution. They were narratives, of
course, that he wrote, as all history must be narration, but they were
narratives not so much of incidents in the life of certain individual
men as of incidents in the life of mankind. He was dealing not so
much with occurrences — these served as illustrations only — as with
the development of principles. In this more difficult and more
philosophical conception of history Mr. Lea was a pioneer in Amer-
ica, and his choice was apparently made independently even of such
European scholars as had preceded him in it.

Why he made this choice has long been a matter of interest to
historical scholars. He himself could probably have told how rather
than why he took this attitude toward history. The wind of human
interest " bloweth where it listeth " and we seldom know just why we
have become so deeply interested in some one particular field of
knowledge or endeavor. But it is to be remembered that Air. Lea's
early surroundings and interests were largely in the field of natural
science. The analogy between the history of institutions and the
study of natural history is very close. There is the same subordi-
nation of the individual to the type, the same interest in logical clas-
sification, the same greater attention to observation than to exposi-
tion. It would seem entirely natural therefore that Mr. Lea, having
become interested in the Middle Ages, would wish to understand
and elucidate the rules and ideas of mediaeval law and organized
mediaeval religion, rather than merely to narrate the story of exter-
nal events during that period.

The same early interest in natural history, acting on a certain

HEXRY CHARLES LEA. xv

type of mind and strengthened by a business training, may be the
clue to ]\Ir. Lea's adoption of so distinctly scientific a method in his
historical work. Scientific method is much the same to whatever
department of knowledge it is applied. It is simply the direct
method, going as immediately as possible to the phenomena which
it is intended to observe; the objective method, treating the phe-
nomena without subjective distortion or personal bias; the compara-
tive method, treating individual examples and occurrences as mate-
rial for classification and generalization ; the rigorous method, using
only facts that can be absolutely verified, or when this is impossible
discriminating clearly the different degrees of certitude of facts.
Allowing for certain difficulties in obtaining and interpreting the
material with which the historian has to deal, no biologist, chemist
or astronomer has been more true to these canons of scientific
method than has Air. Lea in his historical works.

There is one corollary of this attitude toward history, however,
that Mr. Lea was not willing to accept. To most scientific his-
torians it seems no more within their province to express ethical
judgments on the men and institutions of the past, or to draw prac-
tical lessons for the present from them than it is part of the duty of
any other scientific investigators. They deem their work done if
they observe, explain, narrate. According to their view it is no
more the duty of the historian to draw moral lessons than it is that
of the geologist or of the botanist. Air. Lea did not feel so. In
the preface to his " History of the Inquisition of the Aliddle Ages,"
w^ritten in 1887, he said: "' Xo serious historical work is worth the
writing or the reading unless it conveys a moral. ... I have not
paused to moralize, but I have missed my aim if the events nar-
rated are not so presented as to teach their appropriate lesson." His
practice already alluded to of bringing his stores of historical knowl-
edge to bear on present day questions in the form of occasional pam-
phlets or essays indicates the same belief, namely, that it is one of the
duties of the historical student to provide moral or practical teaching
for the community. Yet I am inclined to believe that the concep-
tion of the historian as also a moralist became less pronounced in
Air. Lea's mind as his life went on. In his " History of the Inquisi-
tion of Spain " his judgments of the church are less severe than in his

xvi OBITUARY NOTICES OF ^lEMBERS DECEASED.

earlier work on the " History of the Inquisition of the ^liddle xAges."
His presidential address to the American Historical Association in
1903 was devoted to a vindication of Philip H. of Spain from many
of the charges against him, on the ground that men and institutions
must be judged by the moral standards of their own time, not ours.
He speaks of Motley's condemnation in a certain case as " the lan-
guage of a partisan and not of an historian," and declares that Lord
Acton's famous appeal, " to suffer no man and no cause to escape
the undying penalty which history has the power to inflict on wrong,"
to be based on a mistaken view of the function of history. He
points out that " history is not to be written as a Sunday-school tale
for children of larger growth." He was more willing, I think, in
later than earlier life to tell the story and leave his readers to draw
what moral from it they wished. In his own words, "the historian
may often feel righteous indignation — or what he conceives to be
righteous — but he should strenuously repress it as a luxury to be
left to his readers." Yet he did not entirely reject his earlier view,
for in December, 1907, only two years before his death he wrote:
" I have always sought, even though infinitesimally, to contribute to
the Ijettermcnt of the world, by indicating the consequences of evil
and of inconsiderate and misdirected zeal. The search for truth
has been stimulated by the desire to diminish the consequences of
error."

Yet sincerely as Mr. Lea tried to be impartial in his treatment
of the men and institutions of the past, he has been subjected to
serious criticism, principally from adherents of the Roman Catholic
Church. He has been charged with interpreting medic-eval docu-
ments unfairly, giving undue credit to doubtful documents because
they supported his views, and of allowing his general opposition to
Catholicism to draw him into a partisan presentation of his subject.
The changes have been rung on these charges in many dififerent keys,
but they are all re(hicible to the^e three forms, unfair interpreta-
tion of the records, prejudiced acceptance of documents, and an
anti-Catholic propaganda under the guise of history. Much of this
criticism has been made by men of no standing in scholarship and
may be safely disregarded as unimportant. On the other hand, such
criticism as that of Dr. Bhitzer, published in 1890 in the Historisches

HENRY CHARLES LEA. xvii

JahrhncJi of the GorrcsgcscUschaft, that of Dr. Baiimgarten in his
book " Henry Charles Lea's Historical Writings," published in 1900,
and the obituary essay of Alphandery in the Revue de I'Histoire des
Religions since Mr. Lea's death, must be given the respect due to
serious scholarly opinion. The validity of these criticisms can of
course only be tested by scholars in the same field. But one or two
general observations may be made concerning them. In so far as
the statements refer to the validity or meaning of documents, that is
a scholar's question, the kind of question that arises in all fields of
investigation, that always must arise, and in which ]\Ir. Lea would
have been the first to disclaim for himself infallibility. One of the
difficulties of such criticism, however, is shown in a curious slip
made by one of Mr. Lea's most learned critics, Professor Baum-
garten, of Munich. He endeavors to show at some length that Mr.
Lea is mistaken in what he says of the mediseval rules for keeping
holy the Sabbath day. But Mr. Lea was speaking not of keeping
the Sabbath, the first day of the week, but of the forbidden meeting
of witches with the devil, which was known as the " witch Sabbat,"
and he was absolutely correct in what he said. Professor Baum-
garten is learned, but he does not happen to be learned in the history
of witchcraft, wdiere this expression belongs. As a further indica-
tion of the purely academic character of much of this criticism it
may be remarked that a Catholic reviewer of Baumgarten's attack
upon Mr. Lea while agreeing with him in this part of his work,
proceeds to criticise Baumgarten's own work so severely as quite to
take the edge off his harsh judgment of the American scholar.

But such criticisms, whether correct or mistaken, belong in the
realm of knowledge, not of motive. In answer to charges of bias,
intentional partisanship or unfairness, one can only cite Mr. Lea's
own ideals and practices and the weight of opinion of thoughtful
readers of his works. In this regard it is to be noted that many
Catholic scholars are included among his unquestioning admirers,
and all acknowledge the weight of his scholarship. The very latest
criticism of an adverse nature closes by speaking of him as ce boii
ouvricr de vcritc, "this good laborer for the truth." Mr. Lea him-
self would have wished for no better description.

But there is stronger testimony from the Catholic side. On

xviii OBITUARY NOTICES OF MEMBERS DECEASED.

December 19, 1896, Lord Acton, an English Catholic scholar, who
had already expressed in the reviews a high opinion of Mr. Lea's
work, wrote to him describing the project of the " Cambridge Modern
History," which has now become so well known, and asking him to
write a chapter in the first volume to be called " The Eve of the
Reformation." In his letter Lord Acton uses the following expres-
sions : " This is the important and most critical and cardinal chap-
ter, which I am anxious to be allowed to place in your hands. . . .
It is clear that you are the one indicated and predestined writer,
there is no one else. ... I know of none whom I could go to if you
refuse." Mr. Lea replied in letters dated January 7 and March 22,
1-897, giving a somewhat reluctant consent, and pointing out that such
an article must contain many of the same statements that he had
already made in his published works. In reply Lord Acton wrote,
April 4, saying : " I sincerely thank you for the honor you do me in
giving the aid of your hand and the sanction of your name to our
international undertaking. . . . Your last work contains almost all
I am asking for, ten times told and full measure running over."
After some other intervening letters, the correspondence was re-
sumed in March and April, 1898, when Mr. Lea sent the manuscript
of the chapter, which was acknowledged by Lord Acton with renewed
thanks, and eventually printed exactly as written. Eight years later,
after Lord Acton's death, during a controversy that arose concern-
ing his Catholic orthodoxy, a correspondent in the Tablet, a London
Catholic journal, denied that Lord Acton had asked Mr. Lea to
write this famous chapter. In answer to this Mr. Lea prepared a
communication to the same paper giving an outline of the corre-
spondence which I have just described. Before sending this letter,
however, he saw an article in the London Times of October 30, 1906,
by the present Lord Acton, upholding his father's orthodoxy. In a
spirit of kindliness, and fearing to make this filial task more difiicult,
Mr. Lea decided not to send the correction he had prepared, laid
it away among his papers, and the facts are now made public for
the first time.

Even his severest Catholic critics have restricted their condemna-
tion to a few parts of his work. There is not one of them that fails
to bow to the extent, the depth and the minuteness of his knowl-

HENRY CHARLES LEA. xix

edge. One speaks of his "welcome collection and exposition of
important and universally interesting material for church history,
grandiose capacity for labor, the use of inclusive and often obscure
sources and works of literature," another of the " long and clear
paths he has drawn through the masses of fact he has collected."

The truth is Mr. Lea was a man who keenly resented injustice,
was shocked by unnecessary suffering and deplored waste. In eccle-
siastical history he found much that seemed to him worthy of con-
demnation, and he condemned it often in unsparing terms, blaming
freely men whose actions he thought wicked, and institutions which
he thought conducive to the perpetuation of injustice and the inflic-
tion of undeserved suffering. Those, on the other hand, who look
on the dominant influences of the middle ages with especial sym-
pathy, or feel called upon to defend the Catholic church from criti-
cism, have deeply resented this condemnation. They feel that Mr.
Lea has not given the other and pleasanter side of the story, that
he has not pointed out the amelioration of society, the consolation
to individuals, the gentler and kindlier services of the mediaeval
church. Yet in all fairness it is to be remembered that Mr. Lea's
studies led him through dark stretches of human history, that the
weight of " man's inhumanity to man " must often have pressed
heavily upon his spirit, that sympathy with suffering, resentment
against injustice, hatred of oppression, and grief over ignorance and
prejudice must often have made their appeal rather to the warm
emotions of the man than to the cold impartiality of the historian.
Which of us could read the sad records of the Inquisition, analyze
the motives of men who were a disgrace to the high office of the
papacy, describe the work of the visible church through periods from
which even the most devout of churchmen turn away sick at heart,
and still possess always a judicial calm and a sympathetic spirit?
And yet through all his studies Mr. Lea preserved moderate judg-
ment, optimism and belief in the essential goodness of human nature.

Yet it is not the moral judgments expressed in Mr. Lea's writ-
ings that have most impressed scholars. It is the mass, solidity and
originality of his knowledge, the minuteness of his research, and
the extent of his production. The larger works that I have before
enumerated amount to seventeen volumes. Several of them have

XX OBITUARY NOTICES OF MEMBERS DECEASED.

been reissued in successive editions, in each case with revision,
eliminations and additions. Many of his pamphlets, articles in jour-
nals and other minor works, have involved much original investi-
gation of the same kind as that made for his larger works. The
extent of this investigation is indicated by thousands of references
to works of the most technical and recondite character, in at least
seven languages ; to manuscripts belonging to remote periods, pub-
lished in obscure localities, often by almost unknown authors, and
difficult of access. In addition to these printed references are num-
berless pencilled notes, comments and other evidences of use scat-
tered through the books in his library.

In order to carry out his work as he had planned it, especially his
later volumes, it was necessary to make use of records in European
depositaries which were still unprinted. The University of Oxford
by special resolution ordered that an}- manuscripts in the Bodleian
library needed by Mr. Lea in his work should be sent to America
for his use ; but in the case of archives this was obviously impos-
sible. He was disinclined to go to Europe, and his means enabled
him to make use of another alternative. This was to have copies of
these manuscripts made by copyists there and sent over to him. Of
course much was thus obtained of which he could make no use, but
much was invaluable, and had never before been used by any scholar.
Some two hundred bundles of manuscripts are now on his library
shelves, all of which have been amiotated throughout with his fine
handwriting, and marked as having been copied, excerpted from,
and otherwise utilized or discarded. Only two years before his
death he arranged with j\I. Salomon Reinach to have a mass of
material for his "History of Witchcraft" copied at the Cabinet de
MSS. in Paris, and this he was engaged in examining, as it reached
him, during the last weeks of his life.

The great volume of Mr. Lea's accomplishment, combined with
his practice of having unprinted material copied and sent to him
from Europe, has given rise to a strange misconception of his habits
of work. One of his critics suggested that Mr. Lea, being a man
of wealth, might have secured the services of others ; another that
his numerous references to obscure sources pointed to his possession
of a large body of detailed quotations which could be used by him

HENRY CHARLES LEA. xxi

in constructing his books. A third critic copied and developed these
suggestions, till, according to the well-known process of the growth
of a legend, it has been stated in a French journal that much of
^Ir. Lea's work was done for him by assistants, that he kept a
card catalogue of quotations and references, and that his work
w^as largely a mosaic made by putting together these materials
gathered by others.' Nothing could be more absurdly untrue. No
scholar ever worked more absolutely independently than he, few
ever worked more completely alone. He never employed a secretary
or clerk, never dictated a letter. Just as his library was collected
according to his own judgment, just as the material for his writing
was collected by himself, so his books were written from his own brain
and by his own hand in the most literal sense of the word. He
never spared himself labor in his writing. When his " History of
the Inquisition of Spain " was ready for the press it bade fair to
occupy six large volumes. After serious thought ^Ir. Lea decided
that this was too long, and notwithstanding his eighty years of age
and a pressing realization of the possibility that death might over-
take him with the work of half a lifetime incomplete, he quietly
set himself to the task of rewriting the six thousand pages with his
own pen in shorter form, and within a year completed his task,
reducing it from the six volumes to four. Surely this was a high
instance of courage and the simple dignity of the scholar. No haste
to appear before the public, no pretense, no boasting, no complaint;
simply a sincere and loyal recognition of the claims of scholarship,
and a willingness to grapple with all the difficulties of his subject,
whatever form they might take.

Those who are familiar with Mr. Lea's methods of work know
how he accomplished so much. Day after day, month after month,
year after year, he labored constantly, usually six or more hours a
day, with intense and concentrated yet alert and interested applica-
tion. He often expressed his joy in the combat with a student's
difficulties, his pleasure in labor, his satisfaction in achievement.
Although his health was by no means constantly good, yet for sixty-
five years he did not spend the whole of any one day in bed. During
many years of his later life he sat down regularly to his desk at
two or three o'clock in the afternoon and worked until dinner time.

xxii OBITUARY NOTICES OF MEMBERS DECEASED.

Then in the evening he began again and worked until eleven. And
this occurred seven days in the week.

He began a new subject by copying, translating, tabulating and
summarizing his sources, in his own clear handwriting, on sheets of
paper, with such comments and cross references as occurred to him
in the course of his work. Great stacks of such sheets he took away
with him to the seashore in summer, and classified, combined and
re-read them there. He made it a practice never to begin to write
a book until he had all the material he intended to use in it collected
and classified. Thus in some cases he spent literally years in gath-
ering material before he had written a word of his book in its final
form; and when he came to write he wrote almost entirely from this
highly organized material. Similarly he never sent any part of his
work to the printer until the whole book was completed and revised
in manuscript form. H this patient, systematic, ' self-controlled
method of work is compared with the restless, hurried, confused
and broken way in which most of our production is carried on, it is
not hard to solve the riddle of his great accomplishment.

He obtained singularly little help from others. In his early years he
had, as has been seen, a first rate general education and good literary
training. But when he once entered upon the difficult road of his-
torical investigation, he traveled alone. He overcame its difficulties
with native genius but with much tribulation. His search for the
bibliography of his subject was a hard one. He learned new lan-
guages as he felt the necessity for them. He has himself left a
record of his regret "that there were no scholars here to whom he
could look for guidance in the paths which he desired to follow,"
and that " as a solitary student he was obliged to collect around him
the necessary material." This detachment from other scholars
working in the same line had distinct disadvantages. The editions
of the sources which he used were in many cases not the best, or
those that gave the most help, and he did not obtain assistance that
lay at hand in journals devoted to the investigation of mediaeval
history and in modern works in allied subjects. On the other hand,
this same independence in his work gave a distinction and an indi-
viduality to his thought and writing that added immensely to its
effectiveness. He saved much time from controversy, and he studied

HENRY CHARLES LEA. xxiii

and wrote with a directness that would have been impossible if he
had paid more attention to current writings and discussions in his
field. He seldom asked or obtained either information or ideas
from other scholars. But this arose from no sense of separation,
depreciation or jealousy. It was simply the result of his lifelong
habits of work. He had chosen his field for himself, tilled it in
his own way and reaped its harvest with the labor of his own hands.

He had much pleasant correspondence with prominent European
and American scholars. He was always ready to talk freely to his
visitors and, so far as he took the time to read recent works, cor-
dially praised many of them. He closed his address as President
of the American Historical Association in December, 1903, with
the following words of appreciative recognition of the work of
younger men : " As one of the last survivors of a past generation,
whose career is rapidly nearing its end, in bidding you farewell I
may perhaps be permitted to express the gratification with which,
during nearly half a century, I have watched the development of
historical work among us in the adoption of scientific methods.
Year after year I have marked with growing pleasure the evidence
of thorough and earnest research on the part of a constantly increas-
ing circle of well-trained scholars, who have no cause to shun com-
parison with those of the older hemisphere. In such hands the
future of the American school of history is safe, and we can look
forward with assurance to the honored position which it will assume
in the literature of the world.""

The deepest impression made by a survey of the career of ^Nlr.
Lea as an historian is an overwhelming sense of the impoverishment
of the world of scholarship now that he has gone from it. Doubt-
less the careful, systematic, scientific study of the past will go on ;
science is continuous and progressive, history will more and more
be studied and written as he has studied and written it. Doubtless
others will rise up in his place to continue his work. Confidence in the
future of historical investigation could not be expressed more strongly
than he himself has expressed it in the words I have just quoted. And
yet the broad outlook, the massive acquirements, the trained capacity,
the patient industry, the indomitable perseverance, the sustained in-
terest, the alert and ardent mind of this great scholar, — how can we

xxiv OBITUARY NOTICES OF MEMBERS DECEASED.

spare them from historical research and writing ? When shall we again
have the clear-eyed layman investigating snbjects left too generally
by custom to the churchman ? Where can we seek for the intel-
lectual courage that will extend its view over so many centuries, and
the industry that will prepare itself so thoroughly for the combat
with their difficulties ? What capacities scattered among many pos-
sessors will make up for the combination of powers in one person-
ality? What later travelers along the way of historical study will
see so widely, observe so keenly and record so well as this first and
greatest of American scientific historians?

The President:

The next speaker will be our fellow member, the Right Hon.
James Bryce, the British Ambassador — a conspicuous representative
of the culture of the old world as Mr. Lea was of the culture of
the new.

The Right Honorable James Bryce:

I am asked to speak to you about one of the greatest historians
of our time ; to do so is for me not only an honor, but also a duty,
because I was privileged during many years to enjoy his friendship,
first given to me as a friend and pupil of Mr. Goldwin Smith, and
because I am probably the only member of the British Academy, a
body of which he had been elected some time ago a foreign member,
who is now resident in this country.

Of his public life as a citizen and of his character in its various
private relations, others here can speak with knowledge fuller than
mine ; yet I must not forget to dwell upon and gratefully acknowl-
edge the uniform kindness which he showed to us younger men
when we approached him, and which witnessed to the genial warmth
of his heart. What I have now to say will refer to him as a his-
torical scholar and author.

Anyone asked to say wdiat are the qualities needed for the writing
of history might enumerate them as follows : diligence, patience,
accuracy, the power of critical discrimination, impartiality, penetra-
tion, judgment. All these are qualities which belong to the sub-
stance of historical writing. As regards its form, one would par-
ticularly specify the power of clear statement and the gift of putting

HENRY CHARLES LEA. xxv

color and life into narration, together with those other attributes
which make up what we call " brilliancy of style."

Let us consider Mr. Lea's intellect and the work which it pro-
duced with reference to the various attributes I have enumerated,
and let us begin with the form of his work and of those things
which belong to style and manner.

That which is called literary excellence, /. c, the charms and
allurements of style, was never very much in Mr. Lea's mind and
was altogether subordinated to a consideration of the matter to be
dealt with. Whether it was that he did not think that his talents
lay in the purely literary direction or that he did not much care for
the graces of composition, reckoning merits of form as trifling com-
pared to merits of substance, he paid comparatively little regard to
the adornment of that which he had to say. In this respect he would
have satisfied — as indeed he anticipated — the canons of what is now
called the scientific treatment of history. But his writing had that
which is the greatest merit of style, perfect clearness, both in the
statement of facts and in the exposition of his views of the facts.
It was always plain, direct, intelligible, and with that he was content.
The facts were so interesting to him, and he felt that an exact state-
ment of them ought to be so interesting to all scholars, that he never
spent any time on decking them out with any rhetorical embellish-
ments. If his manner may be called level and business-like, it is
never dull, because the essential facts are carefully selected, words
are not wasted, the matter is so stated as to go straight home to the
reader's mind.

Now let us return to those attributes of the historian which
relate to the substance of his work.

His industry was above all praise. For fifty years he labored
incessantly on his researches, giving to them in earlier days all the
time that he could spare from his business and his public duties as a
good citizen, and in later days devoting to them practically all his
working time. When his health became comparatively weak, he so
arranged his life as to reserve all his forces for study and com-
position. Just so much open air exercise was taken as the interests
of health required, and every moment that could be given to the
library was given.

xxvi OBITUARY NOTICES OF MEMBERS DECEASED.

Nothing could exceed the care and patience with which he in-
vestigated the sources from which lie drew his materials. He veri-
fied every reference, he neglected no out-of-the-way authority from
which information could be obtained. Few recent writers have had
their statements so seldom questioned, and rarely indeed was he
proved to be in error. He rightly held accuracy to be the first of
all the historian's aims and the highest test of the historian's excel-
lence. The splendid library which he accumulated by the labor
of many years, fortunately enabled him to have on his own shelves
an unusually large number of the books that he required, while his
means were sufficiently large to bear the cost of procuring copies
of manuscripts preserved in European collections. Neither trouble
nor expense was spared in procuring these essential materials. It
need hardly be said that whoever travels through unexplored terri-
tory, relying upon original sources, many of which have never been
properly scrutinized, needs a high measure of critical insight.
Whether nature gave Mr. Lea that capacity, or whether he acquired
it by long experience, it certainly had reached in him an unusually
high development, and this is one of the features of his books which
gives them their permanent worth. In accompanying him one feels
one's self always on firm ground.

Some of the subjects which he treated at great length, such as
his monumental histories of the Incjuisition in Southern France and
in Spain and his history of clerical celibacy, deal with subjects in
which freedom from any bias or prepossession, whether religious or
political, is specially needful, and indeed one may say essential in
order to secure the confidence of all readers, whctlier Roman Catholic
or Protestant. Mr. Lea was a Protestant by birth and conviction,
but he was, as a scholar ought to be, perfectly fair in his treatment
of ecclesiastical and religious questions. One may indeed say that
scholarship fails to bear one of its best fruits if it fails to make
a man impartial in handling ecclesiastical history. His books were
never written with any purpose or bias save that of eliciting the
facts. To write in sucli a spirit was far rarer in tlie days when
Mr. Lea began his work than it is in our time. Religious prejudices
were so strong and so general among both Protestants and Roman
Catholics that it was quite unusual to find a writer in whom you

HENRY CHARLES LEA. xxvii

could not discover immediately that he wrote with either a Protestant
or a Roman Catholic color. But it may be said of Mr. Lea that he
not only never suppressed evidence, but also that he always treated
evidence in a purely judicial spirit, endeavoring to give its due
weight to every item, whether or not it fell in with any theory that
he might have formed or any notions he had entertained. In one
of the last conversations I was privileged to have with him he told
me that he had been surprised when he investigated the subject to
find that the Inquisition, terrible as it was, put to death by no means
so many persons as was commonly believed.

When after weighing the evidence and reviewing the facts
established, he had to deliver his own judgment upon them, it was
sure to be both a cautious and a weighty judgment. To large
generalizations he was not very prone, feeling the dangers that
lurked in them, and feeling also that if the facts are fully and care-
fully stated, scholars at least may generally be left to draw their
proper conclusions from them. Great historians may be recognized
hardly more by the fine quality than by the small quantity of the
general theories they propound. It is the untrained men who are
alike facile and feeble in their speculations.

One feature of Air. Lea's judgment deserves to be noted because
it is one which, although apparently discarded by some among the
most recent school of scientific historians, was placed in the fore-
front of an historian's merits by a great man whom it is a pleasure
to name as a warm admirer of Mr. Lea's work, I mean the late
Lord Acton. Mr. Lea was sparing in condemnation, for he had a
charitable mind, and he was not copious in moralizing reflections,
but he carried a clear and sound moral sense into all his judgments.
Cruelty and perfidy and rapacity were hateful to him wherever they
were found. Their foulness was not to be palliated by dwelling on
the distinction between the standards of one age and another.
There are, no doubt, many offences to which we ought to give a
greater indulgence when we meet them in past times than we should
give them now, but even in the rudest communities these three sins
always were sins as they always will be sins, and, as Lord Acton
used to say, they ought not to be excused by any differences of time
or country.

xxviii OBITUARY NOTICES OF MEMBERS DECEASED.

I may sum up the impression which Mr. Lea's intellectual char-
acter and attitude leave upon his readers and left most of all upon
those who knew him personally, by saying that he loved truth with
a whole-hearted devotion. The love of truth is the compass by
which an historian must steer. It is the highest quality in the in-
vestigator, whether his subject be human things or external nature.
It was his love of truth that made him so diligent and exact and
scrupulous in the study of his authorities and in the statement of
his results. It is this quality above all that distinguishes men like
Hallam and Stubbs, Maitland and Gardiner, and in this country men
like Parkman and your latest historian of the United States, Mr.
James Ford Rhodes, from the mere litterateur, however brilliant a
stylist he may be, who occupies himself with history because it is a
subject which lends itself to literary effect. And I may perhaps
add that we in England feel doubly grateful to the United States
when she gives us an historian who makes to European history con-
tributions of permanent value. In observing the widespread and
eager activity with which, in this country, your younger students
are devoting themselves to the history of the thirteen colonies and
of the United States in all its ramifications, I have sometimes been
inclined to wish that more of them occupied themselves with the
history of Europe, which, after all, is a part of your own history,
because you are yourselves a European people, although settled in
another hemisphere. Mr. Lea is a bright example of the services
which an American historian, standing outside the strifes and preju-
dices that still affect the minds of many European writers, can ren-
der to branches of history which eminently require calm and dispas-
sionate investigation.

The vision rises before me of our venerable friend as I used to
see him sitting in his library, surrounded by books that rose from
the floor to the ceiling — rows of precious volumes which he had
gathered with such painstaking diligence — happy among them, gentle
and serene in aspect, and pursuing his labors in an old age which
had left him in full possession of his admirable ]:)owers, wise and
just, zealous and vmtiring as ever in the pursuit of truth. He
thought nothing of fame. He did not seek for recognition either at
home or abroad, and the circle from which he received recognition

HENRY CHARLES LEA. xxix

was the comparatively narrow one of scholars who were able to
appreciate what he had done for them. But he has set before us
a splendid example of single-minded devotion to the enlargement of
knowledge, and has given us a great mass of first rate original work,
work which has stood and will stand the test of criticism. This work
of his, covering some of the most obscure and difficult branches of
research and throwing new light into many a dark corner of the
past, will perpetuate his name and win for it a gratitude of many
generations of historical scholars.

The President :

It is a great pleasure not to introduce, but to present to you
Dr. Horace Howard Furness, the speaker on behalf of the Library
Company of Philadelphia, one of the foremost of Shakespearean
scholars, the genial friend not only of Mr. Lea, but of our entire
community.

Dr. Horace Howard Furness :

Mr. President, Fellozu Members of the Philosophical Society,
Ladies and Gentlemen: Lincoln in his immortal Gettysburg address
taught us, I think, the spirit in which to observe commemorative
services. The deeds that men have done, the tasks they have
achieved — these endure, and our commemorations are for our own
benefit, not for the honor of those whose hands have ceased from
their labour. By rehearsing their victories, we are, ourselves, urged
forward, and in following their example our truest commemoration
is found.

And who would not gladly be a humble follower of such a leader
as he whom we have met this evening to commemorate? From
mouths of wiser censure than mine you have listened to a review of
his manifold talents and activities. A man so various that he
seemed to be not one but all good men's epitome. Of Sir Walter
Scott, who for twenty-five years performed the arduous and varied
duties of Sheriff and Clerk of the Session, it has been said, that an
historian of Edinburgh could hardly escape the conviction that
during those years there must have been in that city and at the
same time, two utterly dissimilar men, both bearing the same name,
the one a poet and literary man of commanding genius and the

XXX OBITUARY NOTICES OF MEMBERS DECEASED.

other a great citizen, ever in public and active civic life. Would
not an historian of Philadelphia come to the same conclusion and
express his conviction that there were here in Philadelphia during
the last half century two men both bearing the identical name,
Henry Charles Lea? One striving and prominent in the heady fight
of politics and reform ; and the other a modest, sequestered scholar,
leading a cloistered life of historical research.

* Far, far indeed behind his worth come all the praises we can
now bestow.'

I cannot analyze his character. His loss to me is too recent
and we are all too close to him. My few words cannot but be
stammering; if haply they only be coherent.

Whatever may be the qualities demanded in a scholar, and espe-
cially in an liistorian, accuracy in statement stands preeminent. It
is the foundation of his work ; on it rests the whole superstructure —
a taint of suspicion of a scholar's truth is the fly which ruins the
apothecary's ointment.

In this accuracy, Mr. Lea ranks among the highest. The sources
whence he drew his statements cannot be impugned. They are the
very words of the speakers, the very acts of the governments, the
very decrees of the church. And of them he urges upon the reader
no interpretation drawn from imagination, or tinged by prejudice.
He gives the documents themselves, from which the interpretation
to be drawn is the bare, unqualified meaning of the very words
themselves.

And herein he reveals to us the lofty attribute of pure intelli-
gence ; pure intelligence is absolutely cold and impartial. This im-
personality elevates his writings to the ruthless dignity of a scroll
of fate. Here are your facts. Lament, deplore, extenuate as you
will, but deny you cannot.

Obedient to this high attitude, an historian need not point the
moral. Whoso cannot of himself find the moral, for him will Clio
for ever inscribe her scrolls in vain. We need no elimination of the
personal question when we read Lea's general conclusions drawn
from a survey of the whole field; and, in less prejudiced and less
impartial hands, we all know how vulnerable such general surveys
are apt to be.

HENRY CHARLES LEA. xxxi

For an historian to attain, however, an eminence from which he
can sweep the horizon, he must be, with a cool head and unclouded
brain, omnipresent in the times whereof he writes. There must be
not only no point of the horizon, political, ethical, and ecclesiastical,
which he has not scanned ; but also the manners, the customs, the
complex trending of thought, the very form and pressure of the
age and body of the time, must be as familiar to him as are those
of his own. To accomplish this as thoroughly as Lea accomplished
it, demands exhaustive research, wide reading, digesting, collating,
analysis, and all held in memory to the point of saturation. In the
presence of such an achievement, as we find again and again in
Lea's works, we can only stand in mute respect and admiration,
tempered with what is akin to awe. To achieve this, difficult as it
is, is a duty imposed on every historian ; and, recognizing this duty,
as " the stern daughter of the voice of God." Lea obeyed it.

John Fiske is said to have observed that " the life of the wisest
man is chiefly made up of lost opportunities, defeated hopes, and
half finished products."

Ls this true of our friend? Ah no! In moments of quiet re-
flection, when to the sessions of sweet, silent thought he summoned
up remembrance of things past, he could not but have been con-
scious that instead of losing opportunities, he had created them ;
instead of hopes defeated, he could count hopes triumphant, instead
of products half finished, he had rounded full and complete the
work of a lifetime wherein no hour was wasted. At such seasons,
with his keen insight into himian nature, he could not but have been
conscious that he had bequeathed to the world a legacy, in com-
parison wherewith wealth turns to apples of Sodom and the clusters
of Gomorrah. Here is a legacy free to all and the more it is used
the wider grows its beneficence and value. It thrives by wasting.

Surely, surely, he could have harbored never a doubt as to its
permanence. In dreaming over its future, well might he have mur-
mured to himself with haughty truth;

" Et tunc magna mei sub terras ibit imago."

"A man's light." says Jeremy Taylor, "burns awhile and then
turns blue and faint, and he goes to converse with spirits ; then he

xxxii OBITUARY NOTICES OF MEMBERS DECEASED.

hands his taper to another." But where shall we find him who is
worthy to accept Lea's taper? Of him, who shall venture to hold
it, it will crave wary walking to keep its flame as pure and bright, as
when it illumined the pages beneath Lea's own hand ; — those pages
which will endure, which cannot but endure. Is it exaggeration
to paraphrase Dr. Johnson and assert that, " time which is con-
tinually washing away the dissoluble fabric of other writers will pass
without injury the adamant" of the "History of the Inquisition"?

And now, as a last word, when the image of the friend, admired
and respected by us all, and so dear to some of us, rises before
me, I would fain in this present circle, close-knit as we are by a
common emotion, breathe one low-toned word of sympathy with
those from whom as husband and father, it was to him so bitter a
pang to part.

Before that sad group we can only stand at a distance with heads
bowed and in silence.

" Fear no more the heat of the sun
Nor the furious winter's rages :
Thou thy worldly task hast done
Home art gone and ta'en thy wages."

" The ground that gave him first has him again.
His pleasures here are past, so is his pain."

The President :

The speaker on behalf of the Historical Society of Pennsylvania
was to have been Mr. Joseph G. Rosengartcn, of I'hiladelphia. but
serious illness in his family precludes him from being here. He has,
therefore, requested Professor Jastrow, of the University of Penn-
sylvania, to read his remarks.

Mr. Joseph G. Rosengarten :

The world-wide reputation of Mr. Lea as a historian forms the
fitting complement to the afifectionate esteem with which his memory
is rightly cherished by his fellow citizens of Philadelphia. As a
reformer he initiated basic changes in our municipal methods. His

HENRY CHARLES LEA. xxxiii

services to the United States Government began early in the troubled
days of the Civil War, when with a few friends he joined the
Union League, and with his pen aroused Union sentiment to thought-
ful action in that great crisis. \Mien troops were to be raised he
was the most active member of a commission of citizens who admin-
istered honestly and efficiently the large sums expended in bounties
and in organizing the volunteers. At the end of long years of
sharp and often bitter contests with the Federal authorities, Mr.
Lea earned the hearty praise of General James B. Fry, the provost-
marshal-general, for his honest and capable management of local
recruiting in the interest of the United States, the state and the
city. His pamphlets and verses formed frequent contributions to
the cause, and the L'nion League may well be proud of the effective
help given in this way at a trying time.

Equally characteristic of the man was his action in resigning
from the League some years later on account of its refusal to throw
its influence on behalf of municipal reform, when Mr. Lea and his
associates were waging their war against corruption in local poli-
tics and administration. He led the attack on the Public Buildings
Commission, and originated the Citizens' jMunicipal Reform Asso-
ciation to reform the government of the city and secure a better
class of representatives in the legislature. It carried on the contest
largely with the help of Mr. Lea's vigorous pen. Flis newspaper
articles and pamphlets brought home to the people the need of
sweeping changes. Much of what he thus advocated was secured
in the new Constitution, and the convention that drafted that instru-
ment drew largely from Mr. Lea's powerful arguments. It was
chiefly owing to his well-directed attacks that the Gas Trust fell at
last, thus relieving the city of a heavy burthen of corruption. Again,
as a member of the Committee of One Hundred, ]\Ir. Lea gave
direction to its eft'orts to secure good city government. What he
did in municipal affairs he sought to do in state and national mat-
ters. He was a strong and active advocate of civil service reform,
and urged the introduction of the merit system of admission to civil
service appointments by open examination.

One of his old and earnest associates says that " !Mr. Lea was
the pioneer in the cause of honest government, and to him above

xxxiv OBITUARY NOTICES OF MEMBERS DECEASED.

any other man is due the credit of first organizing the reform senti-
ment in Philadelphia into a body capable of real work."

Later, when he was more deeply engrossed in his splendid lit-
erary work, although not in good health, he helped in spirit and in
the most substantial way the cause of good government. His deep
interest in his native city was maintained till the end of his life.
Keenly alive to its honor, he set an example of civic duty that is
unfortunately not common in men of his type of mind. He realized
better than most of us that good government can only be achieved
by the harmonious and hearty cooperation of all classes of the com-
munity in civic atTairs.

The same industry that had made him as a mere boy a contrib-
utor of scientific articles to leading journals, and enabled him to
learn from his father's life-long devotion to scientific research, in
maturer years made him a welcome contributor to the leading news-
papers and periodicals on the topics that appealed to the public, for
he was a recognized authority on all public questions that he dis-
cussed.

As late as 1897 he drafted for his associates in Philadelphia an
admirable appeal to the Senate of the United States for the prompt
ratification of the treaty with Great Britain, providing for the arbi-
tration of international questions when not settled by the ordinary
process of diplomacy. In it he showed his mastery of large and
important issues, and put in clear, crisp, significant sentences the
reasons that justified a new departure in the interests of peace.

A complete bibliography of all his contributions on public topics
would be a very long one, and would bring home to his fellow-
citizens a realizing sense of how useful Air. Lea was to them, to the
community in which he liverl, to the state, and to the nation, for all
of which he labored with such unselfish zeal.

An interest in public atTairs and an ability to discuss them on the
highest plane, may have been inherited from his grandfather,
Mathew Carey, a man of mark in the early days of the Republic.
Put the grandson was not onl}- a successful publisher and a man
active in affairs, he was also a diligent student, and even during the
trying days of the Civil War and in the turmoil of discussion of
municipal questions, in the (juiet of his own study he was accumu-

HENRY CHARLES LEA. xxxv

lating the material for that succession of his historical works which
have made him famous as a historian, foremost in the world in the
subjects that he made his own.

Preoccupied as he was, he gave freely of his time and money to
charities, public work and educational schemes. For years a direc-
tor of the Philadelphia Library, he gave it a large reading-room that
doubled its usefulness. A trustee of the University, he gave it the
laboratory of hygiene, and by his will made it the ultimate owner of
his splendid library, a collection of original historical works and
material for historical research that will attract earnest students for
all time. In his own busy life he always welcomed students to his
library, and its treasures were put freely at the disposal of all who
shared his own love of truth and the lessons to be learned by a dili-
gent and intelligent use of the real sources of history, the original
works and manuscript records gathered by him from foreign archives
and repositories.

W'ithout the gift of oratory, or even a fondness or willingness
for public speaking, his contributions with his pen during an excep-
tionally long and active life, formed a solid gain to a sound system
of good government, and to a new light on complicated historical
questions, all with a lofty spirit, a love of truth, and a zeal to help
the world on in its upward progress. Impartial, unpartisan, in-
spired always and only by an unselfish aim, and without any personal
ambition or desire for fame, Mr. Lea was a citizen of whom his
native cit}' and country may well be proud.

Honors came to him in the recognition from scholars and learned
institutions, and from the leaders of public thought at home and
abroad, but unaffected by them except as they furnished him an
assurance of the service that his arduous labors had rendered, he
retained the same simple truth-loving and truth-seeking spirit from
boyhood to the end of his useful and honored life. It is character-
istic of the man that oblivious to the steady growth of his fame as a
scholar, which was even more rapid abroad than at home, his work
continued steadfast and untiring.

His strength and his life ended before he could complete the
'■ History of Witchcraft " in hand at the time of his death. ]\Iuch
original material was collected from various sources, and more came

xxxvi OBITUARY NOTICES OF MEMBERS DECEASED.

after that active brain was stilled, and that busy pen fallen from
his hand. A great amount of notes was made by him with the care-
ful thoroughness so characteristic of his studious preparation before
he began work on his final text, which was then subjected to fre-
quent revision before he would publish the result.

The correspondence of Mr. Lea with public men and scholars
at home and abroad ought to throw much light on his intellectual
growth and development, and on the influence that he exercised
during his long and busy life. His singular modesty, his content-
ment in his own library and in his literary work, his absolute indif-
ference to public honors or recognition, made all the greater his
sacrifice of so much strength, and time, and labor, to public service,
to duty as a citizen. All the more is it important that there should
be a full and complete memorial to him, showing how he was trained
in early youth, developed into a busy man of affairs, active in a great
national crisis, earnest in advocating much needed reforms, and
crowned by the highest authority as a historical author of the fore-
most rank.

Through all his lifetime of activity there ran a stream of con-
stant and wise philanthropy, a steady giving to all good causes, but
only after careful inquiry and investigation, and always without
ostentation or publicity. Of his personal traits one cannot but recall
his kindly gentle nature, his interest and sympathy in all who worked
in the same fields — history, public affairs, scientific research, philan-
thropic and educational projects. None of those who were thus
associated with him would ever have suspected from his modest
bearing that ]\Ir. Lea was a great scholar and historian, whose
works received the highest encomiums of great scholars and his-
torians at home and abroad. They in turn never heard from him
of the manifold public services he had rendered during his busy life.
Let us then pay tribute to his many remarkable achievements in all
his ])ursuits.

There are examples of great historians whose memories have
been honored by making their libraries accessible to students. Our
American universities have many such libraries brought here and
made the shrines for the studious worshiji of successive generations
of scholars. Air. Carnegie made a gift of the lihrarv of Lord Acton

HENRY CHARLES LEA. xxxvii

a special tribute to Lord Alorley. Mr. Lea himself provided that
his library should in due course come to the University of Penn-
sylvania. In making this provision Air. Lea was manifestly actuated
by the hope that his collection might be of service to future genera-
tions of scholars. Such a collection should indeed become the nat-
ural center of the historical work done at the LTniversity, whither
students might come and find every facility for continuing those
researches that made Mr. Lea an example and an encouragement
for all who follow his love for the truth. The noblest memorial to
a great scholar is to provide for a continuance of his work.

I trust, therefore, that I may be permitted to hope that the
priceless collection, so carefully gathered by Mr. Lea during his
long life, should be properly housed so as to make it most fully
serviceable and that amid worthy surroundings its very presence
may serve as an example to which the historians of the generations
to come might turn for fresh inspiration.

Henry C. Lea needs no memorial. His achievements constitute
his monument, but it is important for our sake and for the sake of
the generations to come that his memory be kept alive and that the
recollection of his active and useful life and of his many-sided
labors be kept before us in a manner worthy of the man, the citizen,
the historian in whose honor we have gathered tonight.

The President :

The portrait of ]\Ir. Henry C. Lea, an admirable copy by Mr.
H. H. Breckenridge of Vonnoh's original painting, will be presented
to the Society by the representative of the University of Pennsyl-
vania, and of the American Academy of Arts and Sciences of Boston,
Dr. S. Weir ^Mitchell, the third of our distinguished Philadelphia
triumvirate, whose own portraits in print rival in felicity those of
the artist on canvas.

Dr. S. Weir ^Mitchell:

Mr. President and Gentlemen of the Philosophical Society: I
have had the honor of being selected by the family and friends of
Mr. Henry Charles Lea to present to the Philosophical Society the
portrait of our greatest historian. The portrait I thus place in the
custody of the society is a copy of the well-known portrait by

xxxviii OBITUARY NOTICES OF ^I EMBERS DECEASED.

Vonnoh, painted eighteen years ago, and is regarded by those who
knew Mr. Lea best as an excellent picture of the man as he was.
But that responsive face could never be so put on canvas as to
recall for me the change from the grave scholarly look of attention
to the smile which welcomed a friend to the privilege of a social
hour ; alas ! — here the artist fails us —

" For Painting mute and motionless
Steals but a glance of time."

It is not a part of my function to speak at length of the work of
my friend, or of his personal character and the qualities which made
him both loved and respected. It is probable, however, that no one
of those who speak of him this evening has done full justice to a
characteristic which he possessed in a degree I have met with in no
other man of eminence. The brief contribution I shall here make is
a sufificient record of the extraordinary humility of Mr. Lea con-
cerning works which scholars regard as among the classics of his
time. I hesitated to speak of it because it involved mention of
myself and of a service I was so happy as to render my friend, and
through him to the art of the historian.

About the year 1887, when Mr. Lea was half-way through the
first volume of his work on the Inquisition, he broke down in health
and consulted me. I was able to give him a schedule of life, to
which he adhered with extraortlinary fidelity, and with the result
at' last of allowing him to resume the task which he had for a
time given up. When the first volume of this great work was com-
pleted, he sent it to me with a letter. In it he said that he had held
back the printing of the introductory pages of his book for a week,
because it vVas his desire to dedicate to me a work which could not
have been carried thus far without the health which my counsels
had restored to him. He went on to say that he had felt, however,
so much doubt as to the reception of this book by scholars, that he
finally resolved not to connect m}- name with what might possibly
be considered a failure.

The letter was perhaps a greater compliment than even the dedi-
cation would have been. I think of it with grateful remembrance,
and venture to offer it as m\- contribution to what has been said

HEXRY CHARLES LEA. xxxix

about one of the most remarkable men with whom I have had the
good fortune to be associated in a long life.

The President :

The portrait of Mr. Isaac Lea, a striking copy of ^Ir. Uhle's by
Mr. Thomas P. Anshutz, of the Academy of the Fine Arts, will be
presented by Dr. Samuel G. Dixon, the worthy successor of Mr.
Isaac Lea as President of The Academy of Natural Sciences of
Philadelphia.

Dr. Samuel G. Dixon :

Mr. President, -M embers of the American Philosopliical Society,
Honored Representatives of our Mother Country, Ladies and Gen-
tlemen : It is my privilege tonight to present to you, on behalf of the
family of the late Henry C. Lea, a portrait of Isaac Lea, LL.D.,
by L'hle, that at last it may rightfully take its place in the series of
portraits of distinguished members, which adorn the hall of the
Society.

Isaac Lea's work was ended long ago; he rests beneath "the low
green tent." It may be fitting on this occasion to recall, if only
briefly, his work and services to science.

The honor of membership in this Society has not always an equal
significance. In most cases it is bestowed in recognition of large
performance in the domain of science or of afifairs ; but rarely has
a man's work been discounted, and a member admitted for what he
was expected to perform.

Eighty-two years ago this Society elected to its membership a
young man whose actual achievement was then small ; Init he was
destined to become, in his own special line of research, the most
eminent of his generation.

This young man was Isaac Lea. His life work was the study of
fresh-water mollusks. Born in 1792, of parents belonging to the
Society of Friends, whose English ancestors had followed Penn to
America, young Lea lost his birthright by serving in a volunteer
rifle company towards the end of the War of 1812. About this time
he became interested in geology, under the inspiring influence of
Professor Vanuxem, whose pioneer work on the geology of Xew

xl OBITUARY NOTICES OF MEMBERS DECEASED.

York was soon to begin. Geological horizons are recognized by their
fossil shells, and Lea was thus led to study living moUusks, the better
to understand those in the rocks.

The receipt of some fresh-water mussels, sent by Major Long,
of the \J. S. Engineer Corps, then engaged in deepening the Ohio
River, was the occasion of Lea's first paper, which was published
in the Transactions of this Society for 1827.

Once attracted to this subject Lea found an inexhaustible field
for work. The great river systems of a continent marvelously pro-
lific in bivalve mollusks supplied material. Naturalists in all parts
of the country sent the species of their localities. His enthusiasm
infected others, and from North and South America, India and
Australia, material to be worked up poured in. Lea's work on these
great collections of fresh-water mollusks form a series of thirteen
stately and richl_\- illustrated (juarto volumes, part published by this
Society, part by the Academy of Natural Sciences. His last paper
appeared in 1876.

Every man who sets himself the task of cultivating one plot in
the field of intellectual endeavor must needs resist the voices calling
him to other tasks, lest in scattering his force, he fail of high achieve-
ment. Lea published but little outside of his special work. Several
]:)apers dealing with foreign materials included in gems and other
crystals, and one notable paper, on the reptilian tracts of the red
sandstones of Pennsylvania, were his main digressions.

In whatever direction, however, his researches led him he was
sure to pursue them to a successful end. The value placed upon
them by his fellow scientists is sufiicicnlly indicated by the positions
of honor to which they called him.

I venture upon any estimate of the value of Lea's work with hesi-
tation, since my own studies have been in a field widely diverse. I
can but give the verdict of those competent to judge, whom I have
consulted. Lea's work was mainly descriptive. It was the pioneer
work in his branch of zoology, breaking path for those who came
after. The march of modern zoology could not proceed without
such work as his. And it is the honor of this man that his work
was well (lone. While investigations growing out of Lea's work
may jirove to have what we term "jM-actical"' ap])lications, yet in

HEXRY CHARLES LEA. xli

laying the foundation of our knowledge of freshwater bivalves, Lea's
aim and achievement were purely intellectual. Of him may be truth-
fully quoted those noble words of Tyndall : " The true son of science
will pursue his inquiries irrespective of practical considerations. He
will ever regard the acquisition and expansion of natural knowledge
— the unravelling of the complex web of nature by the disciplined
intellect of man, as his noblest end — and not as a means to any other
end."
The President:

Dr. Dixon, Dr. ]\Iitchell, ]Mrs. Henry C. Lea. and other members
of Air. Lea's family, in the name and on behalf of the American
Philosophical Society, it gives me great pleasure to accept with
sincere thanks these gifts of affection and of a just civic and family
pride. They will find in the notable collection already in the ancient
hall of the American Philosophical Society the portraits of worthy
spirits and warm friends from those of Washington, Franklin, Jef-
ferson and Rittenhouse down to those of Cope, Leidy and New-
comb. There they will ever live, an inspiration to young men of
what may be achieved by a long life of faithful unremitting labor,
and a reminder to old men of what has been thus splendidly achieved
by their predecessors.

MAGELLANIC PREMIUM

Founded in 1786 by John Hyacinth de Magellan, of London
191 I

THE AMERICAN PHILOSOPHICAL SOCIETY

Held at Philadelphia, for Promoting Useful Knowledge

ANNOUNCES THAT IN

DECEMBER, 1911

IT WILL AWARD ITS

MAGELLANIC GOLD MEDAL

TO THE AUTHOR OF THE BEST DISCOVERY, OR MOST USEFUL INVENTION, RE-
LATING TO NAVIGATION, ASTRONOMY, OR NATURAL PHILOSOPHY (mERE
NATURAL HISTORY ONLY EXCEPTED) UNDER THE FOLLOWING CONDITIONS :

1. The candidate shall, on or before November i, 191 1, deliver free of postage
or other charges, his discover^', invention or improvement, addressed to the
President of the American Philosophical Society, No. 104 South Fifth Street,
Philadelphia, U. S. A., and shall distinguish his performance by some motto,
device, or other signature. With his discovery, invention, or improvement, he
shall also send a sealed letter containing the same motto, device, or other sig-
nature, and subscribed with the real name and place of residence of the author.

2. Persons of any nation, sect or denomination whatever, shall be ad-
mitted as candidates for this premium.

3. No discovery, invention or improvement shall be entitled to this premium
which hath been already published, or for which the author hath been publicly
rewarded elsewhere.

4. The candidate shall communicate his discovery, invention or improvement,
either in the English, French, German, or Latin language.

5. A full account of the crowned subject shall be published by the Society,
as soon as may be after the adjudication, either in a separate publication, or in
the next succeeding volume of their Transactions, or in both.

6. The premium shall consist of an oval plate of solid standard gold of the
value of ten guineas, suitably inscribed, with the seal of the Society annexed to
the medal by a ribbon.

&.11 correspondence in relation hereto should be addressed
To THE Secretaries of the

AMERICAN PHILOSOPHICAL SOCIETY
No. 104 South Fifth Street

PHILADELPHIA, U. S. A,

The American Philosophical Society

Announces that an Award of the

HENRY M. PHILLIPS PRIZE

will be made during the year 191 2 ; essays for the same to
be in the possession of the Society before the first day of
January, 1912.

The subject upon which essays are to be furnished by
competitors is :

The Treaty-7naking power of the United States
and the methods of its enforcement as affect-
ing the Police Powers of the States.

The essay shall contain not more than one hundred thousand words, ex-
cluding notes. Such notes, if any, should be kept separate as an Appendix.

The Prize for the crowned essay will be $2,000 lawful gold coin of the
United States, to be paid as soon as may be after the award.

Competitors for the prize shall afifix to their essays some motto or name
(not the proper name of the author, however), and when the essay is
forwarded to the Society it shall be accompanied by a sealed envelope,
containing within, the proper name of the author and, on the outside
thereof, the motto or name adopted for the essay.

Essays may be written in English, French, German, Dutch, Italian,
Spanish or Latin ; but, if in any language except English, must be accom-
panied by an English translation of the same.

No treatise or essay shall be entitled to compete for the prize tht has
been already published or printed, or for which the author has received
already any prize, profit, or honor, of any nature whatsoever.

All essays must be typewritten on one side of the paper only.

The literary property of such essays shall be in their authors, subject to
the right of the Society to publish the crowned essay in its Transactions
or Proceedings.

The essays must be sent, addressed to

The President of the American Philosophical Society,
No. 104 South Fifth Street, Philadelphia, Penna., U. S. A.

^^\

PROCEEDINGS

OF THE

. American Philosophical Society

HELD AT PHILADELPHIA

FOR PROMOTING USEFUL KNOWLEDGE

t Vol. L. May-June, 191 i. No. 199.

CONTENTS.

Notes on Cannon — Fourteenth and Fifteenth Centuries. By Charles E.

Dana 147

Moreau de Saint Mery and his French Friends in the American Philosophical

Society. By Joseph G. Rosengarten 168

The New History. By James Harvey Robinson 179

The Atomic Weight of Vanadium Determined from the Laboratory Work of

Eighty Years. By Dr. Gustavus D. Hinrichs 191

The Origin and Significance of the Primitive Nervous System. By G. H.

PIrker 217

The Stimulation of Adrenal Secretion by Emotional Excitement. By W. B.

Cannon, M.D 226

The Cyclic Changes in the Mammalian Ovary. By Leo Loeb 228

The Solar Constant of Radiation. By C. G. Abbot 235

Self-luminous Night Haze. By E. E. Barnard 246

Spectroscopic Proof-of the Repulsion by the Sun of Gaseous Molecules in the

Tail of Halley's Comet. By Percival Lowell 254

The New Cosmogony. By T. J. J. See 261

The Extension of the Solar System Beyond Neptune, and the Connection

Existing between Planets and Comets. By T. J. J. See 266

The Secular Effects of the Increase of the Sun's Mass upon the Mean INIotions,

Major Axes and Eccentricities of the Orbits of the Planets. By T. J.

J. See 269

On the Solution of Linear Differential Equations of Successive Approxima-
tions. By Preston A. Lambert 274

Problems in Petrology. By Joseph P. Iddings 286

A Study of the Tertiary Floras of the Atlantic and Gulf Coastal Plain. By

Edward W. Berry 301

An Optical Phenomenon. By Francis E. Nipher 316

Obituary Notices of Members Deceased

Jacobus Henricus Van't Hoff iii

George Frederick Barker, M.D., Sc.D., LL.D xiii

PHILADELPHIA
THE AMERICAN PHILOSOPHICAL SOCIETY

104 South Fifth Street
1911

Members who have not as yet sent their photographs to the Society will
confer a favor by so doing; cabinet size preferred.

It is requested that all correspondence by addressed

To THE Secretaries of the

AMERICAN PHILOSOPHICAL SOCIETY
104 South Fifth Street

Philadelphia, U. S. A.

PROCEEDINGS

OF THE

AMERICAN PHILOSOPHICAL SOCIETY

HELD AT PHILADELPHIA
FOR PROMOTING USEFUL KNOWLEDGE

Vol. L May-August, 1911 No. 199

NOTES ON CANNON— FOURTEENTH AND FIFTEENTH

CENTURIES.

By CHARLES E. DANA.
(Read April 20, 1911.)

There can be seen to-day in the fair city of Florence, on the Arno,
an old yellow parchment, upon which is transcribed an edict dated
February 11, 1326. This, expressed in the monkish Latin of the
day, gives authority to the Gonfalonier, the Priors, and twelve
" good men," to superintend the manufacture of " palloctas ferras
et canones de metallo," balls of iron and cannon of metal, which
may possibly, in this case mean brass. What these cannon for the
defence of Florence were like, or what they did, we shall never
know, but with them the real history of ordnance begins ; these little
pop-guns are the ancestors of the 14- and 15-inch B. L. R. (breech-
loading rifle) of today; the fathers threw a wee projectile a hun-
dred or two yards ; the degenerate oflfspring throw a shell weighing
about a ton, fifteen or twenty miles. That the Florentine guns were
the very first no one would assert, but with our present information,
only legend lies back of them.

Of course the credit for the invention is given to the Chinese.
There is not time here to do more than state that the Institutes of
Timiir, about the middle of the fourteenth century, although they

PROC. AMER. PHIL. SOC, L. I99 J, PRINTED JUNE 26, I9II.

147

148

DANA— NOTES ON CANNON.

[April 20,

Cannon of 1 390-1 400.

One of the earliest representations of a Fire-arm. (From German Codex.
Royal Library, Munich.)

191 1.] DANA— NOTES ON CANNON. 149

give full details of the equipment of his troops, do not mention
either cannon or gunpowder. The " Wuh-li-Siao," published 1630,
says " gunpowder came from the outer barbarians."

The mention of an explosive in the Sukranita, a Hindu work
said to ante-date everything Chinese, is admitted by experts, I under-
stand, to be a modern interpolation.

The " Liber Ignium a Alarco Graeco Descriptus," dating back
of the eleventh century, gives some 22 to 35 recipes for the so-called
" Greek-Fire " etc. No G^eek or Aloslem writer ever uses the term
"Greek-Fire." Col. Hime, an authority on this subject^ concludes
that the earlier recipes in the " Liber Ignium," were translated from
the Arabic by a Spaniard. The first four recipes are for the com-
pounding of '■ sea-fire," or, as there described, mixtures which will
ignite "when rain falls on them." Quicklime was the cause of
ignition; to it was added (C. 1300) sulfur, oil, gum Arabic; (C.
1350) sulfur and turpentine; ( C. 1405) sulfur, petroleum, wax.
None of these were true explosives.

Berthold Schwartz, of Freiburg, in Breisgau, the favorite Ger-
man discoverer of gunpowder, made his discovery about 1320 to
1330, at the time the Florentines were popping off their " canones de
metallo." Schwartz is said to have preceded the Florentines in the
making of cannon but this claim has not as yet been established.

Lieut. Col. Hime undertakes to translate the " Epistola de secre-
tis," of the liberal minded Friar Bacon ( I2i4?-i294). This letter
is probably earlier than 1249. It is written according to some
cryptic method, a bad habit both famous Bacons indulged in, and
if the secret of the over-cautious Friar has been guessed with even
partial success, we have a right to suppose that while the good
Friar was " experimenting with some incendiary compositions . . .
the mixture exploded and shattered all the chemical apparatus near
it" (Hime. 161). After this smash-up. Bacon could not fail to be
convinced that saltpeter, sulfur and charcoal, when mixed in right
proportions, had a distinctly explosive tendency — but he never seems
to have advanced the next step and discovered the projectile force
of the compound.

^ Lieut. -Col. Henry W. L. Hime, "Gunpowder and Ammunition," London,
1904.

150 DANA— NOTES ON CANNON. [April 20,

A few more words on gunpowder. In early days saltpeter was
most difficult to procure ; it was collected from cellars and caves ;
later, depots were established for its reception, while strict laws
were passed to ensure its purification and baking. Costing much,
saltpeter was very sparingly used, much to the detriment of the
gunpowder of course. The proportions differ greatly according to
the kinds of powder — whether, for cannon, priming, hand gun, etc.,
from equal parts of each; to, saltpeter, 3, sulfur, i Yj, charcoal, i y-2
to 4: I : I. and 6: 2: i. The formula of today being about 6: i : i.

The price of gunpowder in the fourteenth century seems to have
been almost prohibitive. Assuming that my figures are correct,
which is more than doubtful, for there is no real standard of value,
the price was, in money of to-day, rarely as low as twenty-five dol-
lars, and quite possibly, occasionally, as high as fifty dollars a pound ;
now it costs a quarter of a dollar or less a pound. These prices
rapidly decreased with the systematic collecting of saltpeter.

In a campaign the ingredients for making powder were carried
separately, and mixed only when need came. Here is a note or two
from an authority of about 1465. Keep the three ingredients sepa-
rate, as the niter and sulfur if mixed soon spoil. Better carry the
willow wood unburned, as charcoal absorbs the damp. A secret
process for the preservation of powder : Take clear and very strong
vinegar, make the powder into a paste ; form cakes of four to eight
livres {I'xvrc, about a pound), dry in the shade, sun, or even in an
oven. We are getting close to granulated powder. As the usual
powder was in the form of a very fine dust, the ignition must have
been slow, and much of it was, in all probability, blown out at the
muzzle.

The next mention of cannon is in an "indenture" of 1338, be-
tween John Starylyng, former keeper of the " King's vessels" (Ed-
ward III.) and Hemyng Leget. " Ij [ij] canons de ferr sanz estuff,"
presumably, without ammunition. Also '" un canon de ferr ove ii
chambres, un autre de bras ove une chambre." The cannon with
two chambers was the form of breech-loader often used even for
large bombards until the early part of the next century, and for
smaller iron and brass cannon until the art of casting iron guns was
well understood (in England not until c. 1545), and even into the

igii.]

DANA— NOTES ON CANNON.

151

Loading Cannon of 1390-1400.

Cutting ofif wooden Plug for Wad. (From German Codex. Royal Librarv,

Munich.)

152 DANA— NOTES ON CANNON. [April 20,

seventeenth century, especially for guns used in China. An iron
tube was fastened by bands of iron to a strong stock, with a space
hollowed out at the breech to hold an iron box, the '' chamber,"
sometimes called " a pot." Later this hollow became part of the
gun, a sort of basket, or cradle. The chamber contained the powder
charge, upon which a round section of wood was tightly driven as a
wad. The projectile was placed at the breech end of the tube, with
a straw, felt or rag wad in front to hold it ; the chamber was
wedged against it, then primed, and touched off with a heated iron
rod. Needless to say that a goodly portion of gas escaped between
chamber and tube. These were the earliest quick-firing guns, and
in the sixteenth century were used on the upper works of the ships,
very much as we use quicker firing guns today ; the ancient ones,
when there were four chambers, say, could be discharged about
every two minutes. Later they will be called " murtherers " ; and
w^ell they earned the name when the projectiles consisted of rusty
nails, bullets and scraps.

The chambers, o*" " canones," for the huge bombards, which we
shall meet with later, were held in place by heavy timbers. By or
before 1400 the heavy, wrought-iron powder chamber was welded or
screwed onto the chase of the bombard.

Li the year 1338 appeared, in the Arsenal of Rouen, a terrible
engine of destruction, called by its proud keepers, a " pot de fer
a traire garros," an iron pot for throwing arrows. These arrows,
much like cross-bow bolts, were tipped with iron and winged with
brass, the latter metal obtained from kitchen utensils, cut up and
melted for the purpose. The projectile was wound with leather to
make it fit snug in the barrel. The powder charge for this dread
engine of war was about seven tenths of an ounce of the ill-propor-
tioned powder of that day. When all was prepared, and fire was
applied, the bolt of destruction no doubt emerged, but certainly with
considerable reluctance.

A recipe of a few years later enables us to approximately figure
out the cost of cannon of that day. Five cannon of wrought-iron
weighing 25 lbs. each, and five " canon de metal," presumably brass,
cost three hundred dollars of to-day, say $30 each. All of which is
submitted with considerable hesitation.

19II.]

DANA— NOTES ON CANNON.

153

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154 DANA— NOTES ON CANNON. [April 20.

The first mention of cannon by Froissart, who is as " faithful
as an eye witness," is in the year 1340 at the siege of Quesnoy, on
the northeast border of France, not very far from Valenciennes.
" Those of Quesnoy let them hear their cannons and bombards,
which flung large iron bolts in such a manner as made the French
afraid of their horses. "-

The earliest English use of this word bombard given by Dr.
Murray, is in a quotation from John Lydgate, 1430-. The noun has
left us, but the verb, to bouihard still lingers.

It is usually asserted that the first field-guns were used at the
battle of Crecy, August 26, 1346. The Florentine chronicler, Gio-
vanni Villani, remarks, in the somewhat florid manner of the time,
" the bombards of the English made balls of iron to leap with fire, to
frighten and drive off the horses of the French. . . . That the roar
of the bombards made such a trembling of the earth, such a noise,
that it seemed as if God thundered, with great slaughter of men
and beating down of horses."

This terrible slaughter must have been produced by three small
toys somewhat like blunderbusses, the charge for each of which was
an ounce, more or less, of very bad powder. Cause and effect do
seem disproportionate.

The " Grandes Chroniques de St. Denis " assert that it was the
three cannons of the English that spread panic amongst the Genoese
cross-bowmen and made them indulge in the singular antics by
which they sought to frighten the English archers. In only one
known copy of Froissart is there any mention of cannon at Crecy;
this happens to be that in the library of the city of Amiens, not far
from the battlefield ; there is some reason to believe that the words
in question are an interpolation ; when one remembers that from
Falkirk (1298) to Flodden (15 13) — Bannockburn excepted — the
•English archer, firing ten or more armor-piercing projectiles a min-
ute, with an effective range of 250 yards, was always victorious, it
does appear possible that French writers, with more patriotism than
truth, introduced these terrible cannon into their accounts of the
battle as an excuse for the crushing disaster to their arms.

Edward III. took with him several cannon when he entered

= Chap. IV., Book I., p. 40.

I9"-] DANA— NOTES ON CANNON. 155

France, July, 1346, the month before Crecy. We have too the
King's Privy Wardrobe Accounts, as they were termed, giving Hsts
of guns, ammunition, gunners and other details of the ordnance sent
from the Tower of London to be used at the siege of Calais, which
followed the battle of Crecy.

At this siege of Calais only leaden projectiles are mentioned, and
from the very moderate amount of ammunition required for their
propulsion, the guns although called " great " must have been ex-
ceeding small. The main reliance of besiegers and besieged contin-
ued to be in the huge engines for hurling masses of rock and other
unpleasantnesses.

The derivation "of the word gun is not without interest. Consult-
ing both Murray and Skeat, we find that GuniiJuldr was an Ice-
landic, female, proper name, once applied to war engines. As Gunn
(Icel. Gunnr) signified zi'ar, and hildr a battle, it was certainly ap-
propriate. An account of the munitions in Windsor Castle, 1300/01,
mentions a large ballista named " Domina Gunilda." As there does
not seem to have been any great lady, famous or infamous, so called
in the fifteenth century, this is quite probably a survival of the old
Scandinavian name. The M. E. word gunne, is, of course, but a
shortened pet name for the fearsome lady.

Here is one of the early tragedies connected with cannon. In
1346, the year of Crecy, Peter of Bruges had established a high
reputation for the making of " connoiles." The word may come
from " tonnoiles," which in its turn, may have come from " tuyaux
de tonnoire," or tubes of thunder. In September of that year the
consuls of the city of Tournay hearing that connoiles were useful
to be let ofif in a good town when besieged, desired the aforesaid
Peter to make them one as a sample, and if it proved satisfactory
they would give him an order for more. Peter, the thrifty burgher,
did make one and then proceeded to show the worthy consuls what
it would do. The connoile was placed with great care, outside the
gate " Noire aux Champs." Peter states in his own account that he
loaded the connoile with a quarrel, meaning in this case a heavy bolt,
not an altercation. To the quarrel Peter affixed two pounds of
lead. From the subsequent happenings there is reason to suppose
that he did not omit powder. Peter " laid " the connoile so that it

156 DANA— NOTES ON CANNON. [April 20.

pointed against a door and wall. The spectators heard a " cruel
noise," but the antics of the connoile remain a mystery.

In quite another part of the city of Tournay, an industrious
fuller was busily at work; when lo, along came the erratic quarrel,
with its two pounds of lead, — and the guild of Fullers gave their
deceased brother one of those picturesque funerals for which the
good town is so celebrated. When Peter of Bruges heard of this
mishap, he fled into sanctuary and gave himself up for lost. Then
followed a solemn session of the consuls. Contributory negligence
could not be charged against the Fuller, for if ever bolt came " from
the blue " it was this one. After a long discussion the conclusion
arrived at was : Peter of Bruges fired the connoile at the order of
the consuls ; he was not known to have harbored any ill feeling
against the fuller ; — they might have added that neither ill feeling
nor skill in aiming would have enabled Peter to hit the far-oflf
fuller. The consuls thereupon held Peter blameless, merely remark-
ing that the event was a misfortune and a sad pity.

A curious point is brought out by the list, dated 1347, of artillery,
in its broader sense, for the defense of the castle of Brioul in France.
At the fag end of the list we are told that one man managed two
cannons, and that the efficiency of their projectiles, and of stones
thrown from the towers by hand, was considered about equal.

Before glancing at the great bombard of Caen, 1375, which
marks a considerable step in advance, let me say that during the
fifty years we have glanced at, there have been cannon of wrought
iron, occasionally of brass. The largest of the former did not weigh
over 120 lbs. Breech-loaders were common, and the projectiles were
bolts, or balls of lead — iron balls are referred to, but never stone.

March 20, 1375, an order was received at Caen, in Normandy,
from Jehan Le Mercier. one of the King of France's councillors,
for the building of "a great cannon of iron." ]\Iarch 21 work
began by erecting three forges in the market place, and surrounding
them with a wooden paling to keep the curious at a proper distance.
March 22, the four smiths with their eight helpers began to draw
wages. Fifteen men worked for six weeks, sometimes at night.
April 3, Jehan Nicolle, a master smith, said to have been the best
in Normandy, arrived from " Sap." 2,110 pounds of wrought iron,

o. » 7/

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«y;,u\i.j!iiii'ni.»vww;-'^

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iit-umniiiiiiMiiiiaiimMiiilliM!

Built-Up Wrought-Iron Bombard, 1420-1430.
Length 8 ft. 6 in. Caliber i^V^ in. Basel Arsenal.

158 DANA— NOTES ON CANNON. [April 20,

and 200 pounds of steel were used. The inner tube was formed
by longitudinal bars ; encircling these were tight-fitting rings of iron,
driven on, one touching the other, till they formed an unbroken sur-
face. 400 pounds of the iron was Spanish, presumably a better
quality. The " cuve " for which it was used, may have been that part
of the breech which enclosed the powder chamber. 200 pounds of
steel were needed; could the chamber have been of that metal?
The chamber seems to have formed a permanent part of the bom-
bard, as the vent is specially mentioned with its large projecting
apron of iron.

After the metal part was finished ninety pounds of rope was
wound about the gun, for what purpose we are not told. Over this
was sewn a cover of hide to prevent the rope rotting or the metal
rusting if exposed to rain.

The manner of attaching the monster to its heavy wooden bed
and braces, is fully and confusedly described. General Fave thinks
its carriage was a kind of cage, somewhat like that used by black-
smiths in France for shoeing unwilling animals. Four stone balls^
size not given, were provided, at a cost of two sous six deniers each
($1.50? today). Two of these were used in the proof rounds.

After this date (1377) the size of cannon rapidly increased.
Froissart mentions 140 cannon used at Odruik or Outherwyck, by
the Duke of Burgundy, in 1377, which threw balls of 200 pounds,
A work (name not given) professing to quote contemporaneous
authority, mentions a cannon of the Duke of Burgundy, 1377,
throwing a shot of 450 pounds, which would require a calibre of say,
21 inches.

1382, at the siege of Oudenarde by Philip van Arteveld, the
Flemings made use of a "marvellously great bombard," so they
said, at least. They added, that when this bombard was fired, by
day it could easily be heard a distance of five leagues, and by night
ten. It made such a terrible din (French "noise") that to those
who listened, it seemed as if all the devils in hell were rushing on.
The rather imaginative old chronicler says that this monster had
"53 pouces de bee" (mouth). Englished, a trifle over 58 inches.
Either we must credit him with having measured the circumference,
— rather an unusual manner of classifying artillery, making the real

I9II.] DANA— NOTES ON CANNON. 159

caliber only about i8 inches, or else, — but the alternative is too
painful.

The accounts of the fighting about Chioggia, 1380, between the
Genoese under Pietro Doria, and the Venetians under their beloved
Vittore Pisano, are well authenticated, and give a vivid picture of
the power of these old bombards. January 22, the great bombard,
a two-hundred pounder, was fired by the Venetians at the campanile
of Brondolo; it knocked out a large piece of wall, and some of the
flying stones struck and killed Pietro Doria, the Genoese commander,
together with his nephew. The next day the same bombard brought
down a still greater piece of the same campanile, killing 22 men ; so
that as an implement of slaughter, the clumsy thing was a success
and endeared itself proportionately to the Venetians.

Before leaving the fourteenth century a few short notes might be
added.

The castle of Tannenberg, in Germany, was captured 1399. A
huge bombard belonging to the city of Frankfort a/M., was loaned
to the besiegers. Tremendous difficulties were met and overcome in
getting the gun into position, very close to the castle. The first pro-
jectile stuck in the wall; the second passed through, and soon the
defences were in ruins. These were never rebuilt. Excavations
were made in 1849 and many stone balls were found. They varied
in diameter from three inches to 31)^ inches, the latter weighing
825 pounds, and unquestionably one of the shot for the " Frank-
furter Buechse."^

Napoleon gives an inventory of the Artillery of Bologna,
1381/97, in which stone balls of 1,000 pounds for bombards and
mortars, together with iron balls of i, 2, 3 and 6 pounds are men-
tioned.

A word about field-guns. Froissart,* speaking of the capture
of the castle of la Roche sur Yon (1369) by the Black Prince, men-
tions " several cannons and springalls with which the army was
provided, and from long custom had always carried with them."

In the year 1382 the bumptious burghers of Bruges were engaged
in one of their usual wars with their equally bumptious neighbors

' " Die Burg Tannenberg and ihre Ausgrabung," Hefner und Wolf, Frank-
furt, a/M., 1850.

* Chap. 268, Vol. I.

160 DANA— NOTES ON CANNON. [April 20,

of Ghent, who took the field 5.000 strong with 200 " ribaudequins."
The latter were heavy built push-carts — Napoleon calls them
" wheel-barrows/' bearing in front two or three, sometimes more,
of the small cannon of the day, with an ugly fringe of bristling
lances projecting beyond. These disagreeable field-pieces were
trundled along in front of the line of battle. The efifect of two lines
of *' ribaudequins '" meeting and neutralizing each other must have
given rise to some curious tactics in battle. In this case the 5,000
of Ghent formed themselves into a dense mass and with " ribaude-
quins " in front, drove off 40,000 men of Bruges.

At the battle of Roosebeke, November 27, 1382, where the Flem-
ings were cut to pieces by the French and their leader Philip van
Arteveld killed, Froissart states that the battle began by " a can-
nonade with bars of iron and quarrels headed with brass."

This battle did not end the war, and a curious picture of the
ineffectiveness of the smaller cannon of the day is given by Lieut,
Gen. Sir Henry Brackenbury, in his account of the siege of Ypres
by the English and Flemings. The siege lasted from the eighth of
June. 1383, to the eighth of August. During that time a steady
cannonade was maintained, but apart from interfering with the
sleep of the good burghers of Ypres, not a soul was one whit the
worse. Two guns were advantageously posted in front of one of
the gates, and kept up a steady fire, in all 450 shots. When the
siege was raised those of Ypres were forced to admit that the gate
in question was in need of immediate repairs. ]\Iuch danger to the
inhabitants was avoided by a thoughtful device; the besiegers con-
siderately heralded by a trumpet blast each discharge; this enabled
promenaders to step aside and avoid any possible annoyance from
intruding cannon balls.

Another curious picture of by-gone days is given us in the
"Issue Roll of the Exchequer for 1384," in which the amount of
payments for the hire of cannon and cannoniers is given, making it
plain that private individuals often owned one or more cannons
which they hired out like cabs.

Viollet le Due mentions this same custom on the continent; he
says that during the middle ages the engines of war were made by
non-military workmen, and the same rule prevailed after the intro-

1911.] DANA— NOTES ON CANNON. 161

duction of cannon. Xot only did ordinary mechanics make the new
artillery, they also served it; letting their cannon for hire as one
lets carts and drivers ; and it was not until the death of Charles VII,
1461, that they formed companies of bombardiers and culveriniers,
heavy and light artillery, like the companies of cross-bowmen and
archers, gave to them military organization, and placed them under
the command of the grand master of artillery.

The fifteenth century was one of development, very important
but less startling than its predecessor.

The most marked advance was in cast bronze and iron guns.
Pretty much any date after 1400 may be taken as the beginning of
that phase of the smelter's art. Erfurt claims 1377 as her begin-
ning; it seems needlessly early, but no one can say her nay. There
are two cast-iron guns in the Leipzig ]\Iuseum, one between 1400
and 1420; another, less archaic. 1420 to 1430.

Francis Grose says :

It seems extremely strange, that none of our workmen attempted to
cast them, [cannon] till the reign of King Henry VIII. when in 1521, accord-
ing to Stowe, or 1535 [Camden says], great brass ordnance, as canon (sic)
and culverins, were first cast in England, by one John Owen, they formerly
having been made in other coimtries; . . . 1543. . . [Stowe] . . . the King
minding wars with France, made great preparations and provisions, as well
of amunitions and artillery as also of brass ordnance ; amongst which at that
time, one Peter Bawd, a Frenchman born, a gun-founder, or maker of great
ordnance, and one other alien, called Peter Van Collen, a gun-smith, both the
King's freedmen, conferred together, devised and caused to be made, certain
mortar pieces, being at the mouth, from eleven inches up to nineteen inches
wide. . . . and after the King's return from Bullen [Boulogne], the said
Peter Bawd by himself in the first year of Edward VI. [1547] . . . did also
make certain ordnance of cast yron of diverse sorts and forms, as fawconets,
falcons, minions, sakers, and other pieces. Chamber'd pieces for throwing
stones, called cannon-perriers, port-pieces, stock-fowlers, sling-pieces, port-
ingale-bases, and murtherers, were about this time much used in small forts
and on shipboard.^

Of course all these guns were cast hollow ; that is a core covered
with clay, was suspended in the center of the mould while the metal
was poured in. Despite all precautions it was very nearly impossible
with the imperfect means then in use, to keep this core in place and
true; cavities formed in the metal about it, and the scoria did not

° Francis Grose, " Military Antiquities."' London, 1788, II., p. 383.

162 DANA— NOTES ON CANNON. [April 20.

rise freely; certainly too much cannot be said in praise of the
founders who could cast such a gun as the serpentine of Charles
the Bold (say 1476), in the arsenal at Neuveville, near Bern; a cast-
iron field gun some fifty-two inches long, and 2-inch bore.

Machinery for boring cannon is said to have been invented by
Lew, in Switzerland. It was introduced into France 1740/44, by
Jean Maritz, born in Bern (1711-1790), who, after accepting office
under the French was naturalized. IMaritz seems to have been the
first who thought of placing the gun horizontal and making it, not
the drill, revolve.

The Great Bombard, the characteristic gun of the latter half of
the fourteenth century and the greater part of the fifteenth, was
often, in its early days but a huge tube — '" tuyeau de tonnerre." It
is possible that after the frequent burstings, the occasional sur-
vivor noticed that these annoying accidents usually had their origin
just in front of the chamber, about where the great stone ball was
placed. The gun-maker would naturally strengthen this portion
with much thicker bands, and doubtless he would soon deduce the
fact that the strain decreased from the bursting point to the muzzle,
then he would shape his gun to suit. The early gunners suffered
terribly from the bursting of their guns. James II., King of Scot-
land, was killed at the siege of Roxborough Castle, 1460, in this
manner; 1470, a bombard near Paris burst, killing 14 men and
wounding as many more.

It was long before the early gunner discovered (the figures are
for a 4.25 inch caliber) that the proportional pressure on the bore
increased alarmingly with the weight of the ball; 3.6 per square inch
for stone; 10 for iron ; 10.9 for bronze ; 14.5 for lead. For the same
caliber; the cost for one round; 4-inch ball, charge 1-9 wt. of ball : —
In money of to-day: with a stone ball, $1.25; iron, ?4.75 ; lead,
$6.25 ; bronze, $9.00.

Stone balls had two bad defects — they were apt to shatter to
pieces when used for breaching purposes against heavy masonry ;
and their rough surface greatly damaged the interior of the bom-
bard ; it was sought to correct these defects ; the first by bands of
iron about the ball ; the second by enclosing the ball in an envelop of
soft lead.

191 1.] Dz-VNA— NOTES ON CANNON. 163

The difficulties in the construction of these big bombards were
greatly lessened by the system of forging the very heavy breech piece
so that it could be screwed to the chase — and unscrewed, when de-
sired ; the square holes for the levers, that worked like capstan bars
on board ship, are conspicuous in such guns, usually in the rear
ring of the chase, and at the rear end of the breech. In some bom-
bards there were three divisions, greatly adding to convenience in
transportation.

Here are the dimensions of the largest bombard that has come
down to us, the one on the Place du Marche at Ghent. The lady is
called " Dulle Crete." which they tell me can be translated " Mad
Meg." Her caliber is 26" ; interior of chase 10' 4", or five calibers.
Chamber caliber 10.23", l<?i''gth 4'-6.i6" ; five to six calibers. The
exterior length 16' 6". The gun is built up of 32 longitudinal iron
bars, 2.17" wide. 1.2" thick; these are soldered together. Over
them are 41 iron rings, welded together and diminishing in thick-
ness from the junction with the breech to the muzzle, except the
three which form the muzzle moulding or swell. In addition, there
are 20 bands, called " rondelles." in two of which, the one at the
extreme end of the breech and the one at the end of the chase,
are holes for the levers used in unscrewing breech from the chase.
Curiously enough, the breech is not exactly in line with the chase,
inclining slightly to the left. — might possibly be a trifle trying for the
right-hand side of the chase after a few shots. 3ileg's weight is
36,080 pounds, but painters of that day represent Flemish women
of her class as distinctly heavy. The ball weighed 748 lbs., and the
powder charge was 88 lbs., between ^ and % the weight of the pro-
jectile. The range was about 3,000 yards, at least Meg claimed that,
though her efl:'ective range could not have been more than three hun-
dred yards. But, it is only fair to remember that in Nelson's day
six hundred yards was long fighting range.

The date of this huge, but rather useless engine of construction
— destruction. I fear, would be gross flattery — is rather uncertain.
The Flemings took it to the siege of Oudenarde, in 1452 ; a coat-of
arms I found near the vent is that of the father of Charles the
Bold, called " Philip the Good," because he was bad. He warred
from 1422 until 1467.

]64 DANA— NOTES ON CANNON. [Ap"' 2°.

At the siege of Caen, in 1450 — this is aU quoted from an account
in very bad Latin — the town was ringed about with twenty-four
bombards, horrible to behold, for they were of such immense size
that a man could sit in any one of them without bending his head !
Possibly this old chronicler's account was intended to fall into the
the hands of the besieged — though of course, cannon of that size
would make very comfortable quarters for at least 48 men.

The preceding is but a dip into the doings of bombards; we have
not touched on that most interesting one, " Mons Meg," at Edin-
borough Castle ; nor the " Michelettes," at Mont St. Michel, which
are of unique value ; the " Faule Mette," was a cast bombard, a resi-
dent of Brunswick, but alas she has disappeared.

Wooden guns are of great interest, not only on account of the
frequent tendency to burst which must have been theirs, but also
on account of the very unreliable descriptions of them that we
possess.

About 1450 trunnions appear (not the first, by any means) on
some of the Burgundian guns, adding, of course, greatly to their
efficiency, both in permitting more exact aiming and as a help to
resist the recoil. Omitting all other technical details it may be of
interest to take a look at the Burgundian, and afterwards at the
French artillery.

The town of Neuss, near the Rhine, and not far from Duessel-
dorf, was unsuccessfully besieged by Charles the Bold, 1474/5- The
Burgundian artillery, then the best in Europe, was well represented
there, and. more or less careful accounts of it have come down to
us. The following list is taken from Napoleon's " Etudes " ; un-
fortunately the calibers are omitted.

Nine large bombards. Eight bronze bombards, 8 to 11 ft. long;
these had lions' heads at the muzzle. Ten courtaux, 4 feet long,
on wheels. These were a little like the carronade of just before
1800. to forty or fifty years after; there are accounts of courtaux
which carried 60-lb. balls and were used as siege pieces. 115 Ser-
pentines, one of which was 13 feet long. Six serpentines of bronze,
with dragon heads at the muzzle, one of these guns was 8 feet long.
Sixtv-six serpentines 6 to 9 feet long. Fifteen others of <-he same
caliber weighing 4,000 pounds.

I9II.]

DANA— NOTES ON CANNON.

165

inWM StRrlMINl [N rtR rORCt (rsl,b„

Field-Guns of Charles the Bold, c. 1476.
Fig. I. More ancient build ; wronght-iron bars, banded. Fig. 2. Cast-
iron; modern looking gim and carriage. Fig. 3. "Portable bombard";
throws incendiary bomb or stone ball.

Like many other weapons, artillery is not of much service unless
vou know how to use it, and do not hesitate to use it. Charles the
Bold was the last of the knights-errant, unless we include the chival-
ric Don Quixote. Cannon had changed all that and Charles was a
failure, though a magnificent one.

166 DANA— NOTES ON CANNON. [April 20,

March 2, 1476, was fought the battle of Granson ; Charles of
Burgundy had 20,000 men and his splendid train of field-artillery ;
both these he proceeded to post as badly as he conveniently could.
The Swiss always attacked in solid squares, impervious to cavalry
but just the food for cannon to devour. Nine thousand men, and
absolute silence, save the word of command ; instant death to who-
ever faltered. A few shots took elTect on that solid human mass,
as it moved slowly towards the guns, each ball mowing down ten
or a dozen men ; then a dip in the ground protected them, and the
balls passed over their heads. Now was the time for Charles to
have concentrated his artillery fire on the square and rent it to pieces,
for his cavalry to drive off the field. Instead, time and again he
launched his magnificent gendarmerie against that bristling wall of
steel, those 16-foot spears held by sturdy mountaineers who knew
not fear. Every attack failed, panic followed, and that splendid
Burgundian artillery now adds interest to a score of Swiss museums.

Napoleon III. and General Fave consider the artillery of Charles
VIII. the beginning of that arm of the French service. Of course
guns of earlier days still lingered on, but the newer ones took on
almost the form they were to retain for three hundred years.

Guns changed but little from 1500 until the astounding develop-
ment of today. Drake fought the Spaniard with almost the same
guns that Nelson used at Trafalgar.

A better organization, and an improvement in tactics was made
by Charles of France, before his great Italian campaign of 1495. O"
the other hand he w^as opposed by very different foes from the
heroes who defeated Charles of Burgundy at Granson, Morat and
Nancy. One may safely say that France easily, almost pityingly
scattered before her powerful guns the very worst troops the world
contained at that time. Burgundy, on the contrary, had faced the
bravest and best fighters history tells of. Swiss tactics, the old
phalanx of Greece, steadily adhered to. soon became obsolete, and
the system of rushing the guns with such unwieldy squares, received
its death blow on the days of Marignano, 1515; when, cannon to
the right of them, cannon to the left of them, cannon in front of
them, volleyed and thundered. Two days of carnage failed to
shake the Swiss ; but when Francis I., massed his artillery, and the

'9^1-] DANA— NOTES ON CANNON. 167

Swiss attack was exposed to a cross fire that tore their squares to
shreds, — just what Charles of Burgundy should have done at Gran-
son, they sullenly fell back and the rule of the cannon began ; alas,
that its end is not yet in sight.

Ten years later this same Francis was routed and captured at
Pavia; one reason for it was that he stupidly masked his own
guns by advancing his troops in front of them; another, that many
of the Swiss of Marignano were then fighting on his side ; but those
days of ^larignano and the slaughter were not forgiven ; so when the
crisis came, the Swiss, despite the despair and entreaties of their
officers, threw down their arms and pretended to be cowards, — for a
Swiss it could only be pretence.

AUTHORITIES.

■'Ancient Cannon in Europe"' (fourteenth century), Lt. Henry Brackenbury
(Later Lt.-Genl.), Proceedings of the Royal 'Artillery Institution, 1865,
Woolwich, Eng.

" Etudes sur rArtillerie," Prince Louis Napoleon, Paris, 1846.

■' Etudes sur I'Artillerie," General Fave, Paris, 1862.

■' Quellen sur Geschichte der Feurwaffen," Leipzig, 1877.

" Military Antiquities Respecting a History of the English Army," Francis
Grose, London, 1812.

'■ Principles and Practice of Modern Artiller\-," Lt.-Col. C. H. Owen, Lon-
don, 1873.

" Gunpowder and Ammunition," Lt.-Col. H. C. L. Hime, London, 1504.

■' Naval Gunnery," Capt. H. Garbett, London, 1897.

" Catalog of the Musee d'Artillerie," Paris.

" Encyclopedia Britannica."

■' Encyclopedie Larousse."

" Diet, du Mobilier Frangais," Viollet le Due.

" Biographic Nouvelle."

Author's notes, etc.

MOREAU DE SAINT MERY AND HIS FRENCH FRIENDS
IN THE AMERICAN PHILOSOPHICAL SOCIETY.

Bv JOSEPH G. ROSENGARTEN.
{Read April so, igii.)

Born at Fort Royal, Island of Martinique in 1750, dying at Paris
in 1819, Moreau de St. Mery had a career characteristic of the stormy
period through which he passed. Of a good family of Poitou, his
father's early death left him with little means. At nineteen he came
to Paris, became a King's gendarme, studied law, letters and mathe-
matics. Returning to Martinique he became a lawyer at Cap Frangais,
and in 1780 a member of the Upper Council of Saint Domingo. He
classified the laws of the French Colonies of the Antilles ; discov-
ered and restored the tomb of Columbus, and sent many scientific
papers and many curious archcological articles to the American
Philosophical Society, and was elected a member in 1789.

Returning to Paris as a member of the Constituent Assembly
from Martinique, he was warmly welcomed by the scientific world
in recognition of his frequent contributions to scientific societies.

When the French Revolution broke out, he was elected President
of the Electors of Paris, twice addressed Louis XVI. on their behalf,
and was fond of boasting that for three days he had been King
of Paris, and helped to secure for Lafayette the command of the
National Guard.

Elected Deputy from Martinique in 1790, he brought many colo-
nial matters before the Constituent Assembly, and in 1791 became
a member of the Judicial Council.

Wounded in an attack by a maddened crowd, he took refvige in a
country village in Normandy, escaped the guillotine and came to the
LTnited States. After a short stay in New York, he settled in Phila-
delphia in 1793, opened a book store at Front and Walnut Streets,
and became active in the Philosophical Society, attended its meet-
ings regularly, contributing papers, making gifts to its collections,

1G8

191 1-] ROSENGARTEN— MOREAU de SAINT MERV 169

introducing many of his fellow exiles, some of them soon elected to
the Society. Returning to France in 1799 and making use of his
distant relationship to Josephine, wife of Bonaparte, he was em-
ployed by Bonaparte in the preparation of a Maritime Code. Ap-
pointed to the Council of State in 1800, he was sent in 1801 to Parma
as Administrator of the Duchy of Parma, fulfilling his duties with
moderation, but showing a lack of firmness and energy that cost
him his position, and the enmity of Napoleon, who sent Junot to
replace him. and to end a threatened revolution by fire and sword.

When he lost his place in the Council of State, he told Napoleon
that his honesty need not be feared, for it was not contagious in that
body. The Empress Josephine helped him. and afterwards he be-
came historiographer of the Marine Department.

He sold to the French government, for a pension from Louis
XVTIL, his large collection of historical papers, documents, maps,
etc., often mentioned by recent historians. One unkind critic, who
worked at making a calendar of his papers, says he sold to the gov-
ernment not only the copies he had made, but many .originals which
he had taken from the files in his care. His printed works include
one in six volumes, on " The Laws and Constitutions of the French
Colonies in the West Indies from 1550 to 1785," Louis X\T.
ordered a copy to be placed in each French colony in America.

His "History of Saint Domingo" was translated by William
Cobbett, then living in Philadelphia, and his list of subscribers
included many notable Americans then in office and a large number
of French exiles in the L^nited States.

He translated and published a pamphlet on " The Prisons of
Philadelphia," by Rochefoucauld Liancourt, reprinted in Paris and
in Holland, and in one of Rochefoucauld Liancourt's bulky six vol-
umes of his " Travels in the United States." He had the honor of
an eloge by Fournier Pescay printed in Paris in 1819 and the bio-
graphical dictionaries give the dates of his various publications, of
the offices he held and make mention of his best service: the collec-
tion and preservation of an immense number of papers, maps, etc.,
relating to the French colonies in America, from their origin down
to the French Revolution. Calendars of parts of them have been

170 ROSENGARTEN— MOREAU de SAINT MERY. [April 20,

printed by the Canadian Archive office and by the Wisconsin His-
torical Society and in France.

His shop at Front and Wahiut was the rendezvous of all the
notable French exiles then in Philadelphia, and he entertained them
very modestly, — cooking his own simple meals in his rear office, and
sharing his good wine with them. He figures in the " Memoirs " of
Talleyrand and in the " Travels '" of Rochefoucauld and in the books
on the United States by Brissot and Volney and other French writers.

He translated and published two big quarto volumes on China by
Van Braam. who had resided in that country as a member of a
Dutch embassy. The book was dedicated to Washington. Van
Braam became a merchant in Charleston in 1783 and was naturalized
in 1784, then made his voyage to China, returned to Philadelphia in
1796, bringing with him several Chinese servants, and a large collec-
tion of paintings, drawings, maps and curios, which he exhibited in
Philadelphia for several months, then kept in his house near Bristol,
" China Hall " on the Delaware. In the appendix to the second
volume of his book, there is a detailed account of his collection,
filling many pages. He too was elected a member of the Philo-
sophical Society in 1797.

jMoreau de St. Mery printed a catalogue of the contents of his
book store, of y2 pages, including many books in English, French,
Italian, Spanish, Latin, German, Dutch, maps, music, and advertised
" a general business of stationers, booksellers and dealers in engrav-
ings, a printing office and book bindery, to fill orders for books from
Europe, deal in every kind of business on commission, and will not
spare any care in studying to accomplish their enterprise intended
to propagate and diffuse knowledge," and at the end of the catalogue
of books, etc., offered for sale, " particular goods out of the book-
sellers' station, everything belonging to the Fleecy hosiery manu-
facture of New York, as foot and ankle socks, goutty mittens and
stockings, shirts with and without sleeves, drawers, muff"s, etc.,
elastic garters and gallices of different sizes." Perhaps his field was
too large, and the public not appreciative, for he failed for $5,000,
and Philadelphia lost the advantage of such a bookseller, printer and
publisher, as well as philosopher, author and translator.

191 1.] ROSENGARTEN— MOREAU de SAINT MERY. 171

Xo doubt the same industry and energy led him to make the
large collection known by his name, now in Paris, of original docu-
ments, copies, maps, etc., filling 287 volumes, bought by the French
government, and now in its great archives for the use of students of
colonial French history.

That St. Mery was well thought of in Philadelphia, during his
residence here is attested by the long list of subscribers to his book
on Saint Domingo, including Vice-President John Adams, Adet, the
French minister, Benjamin Franklin Bache, William Bingham.
Thomas Bradford. Samuel Breck, Rev. Dr. Collin, Alexander James
Dallas. P. S. Duponceau. Dupont. of Wilmington. Rufus King, Dr.
Logan. Xoailles, Timothy Pickering. Rochambeau, Talleyrand, John
\^aughan. A'olney. and many notable French exiles both in Phila-
delphia and elsewhere in the United States. Many of them were
elected members of the American Philosophical Society, and its
minutes show that its meetings were frequently attended by Talley-
rand, Rochefoucauld. A'olney. \'an Braam, and its library has many
books, the gifts of St. ^lery and his fellow exiles.

In a recent biography of Talleyrand we are told that when he
landed here in 1794, it was the finest city in the United States, full
of life, everywhere new buildings and work on them going on, the
streets full of elegant equipages, crowded with men of business,
workmen and sailors.

Chateaubriand speaks of the beauty of the Quakeresses. Every
stranger from Europe was welcomed by the wealthy merchants, —
life was very expensive, board $8 to $12 a week, without fire, light
or wine ; a negro servant cost $10 to $12 a month even with food and
washing. Emigres of all political creeds found a Xoah's ark of
refuge in Philadelphia. Talleyrand's arrival was quite an event;
he found old friends, old soldiers of Lafayette, fellow members of
the constituent assembly, among them Blacon. who had been deputy
from Dauphine and one of the intermediaries between Mirabeau and
the King. Hamilton gave him a warm welcome, but Fauchet. the
French ^Minister, prevented Washington from receiving him, and
Washington wrote to Lord Lansdowne, explaining why his letter of
introduction did not enable him to meet Tallevrand. However, he

172 ROSENGARTEN— MOREAU de SAINT MERY. [April 20,

did not busy himself with poHtics. but at once began speculating in
land, then the great money-making business. The Scioto Company
was then all the vogue in Paris. The Holland Land Company was
buying right and left. LaForest, the French Consul General, had
bought an estate in Virginia in 1792. Noailles and Omer Talon in
association with Robert Morris had bought large tracts of land on
the Susquehanna for a colony of French royalist exiles, offering
land, which had cost them 15 sous an acre for 6 francs, as a refuge
from France.

Talleyrand urged Mme. deStael and his friends in Europe to
send money for investment, and he proposed buying land in Maine
from General Knox. He told Moreau de St. Mery that he had a
plan for settling in Louisiana, and was a frequent visitor at St.
Mery's book store, meeting there his old friends and fellow exiles, —
Fayettists, Girondists, Constituents, Jacobins, Royalists, one of them,
Count de More, says '* wandering like ghosts, full of regrets, lost
hopes and disappointment over their shattered political careers."

Mor.eau de St. Mery often spoke of the three days in 1789 when
as president of the Electoral College he was King of Paris. But
while the others were bewailing their hard fate, Moreau was busy
with his shop and his books, and Talleyrand wrote to Paris of
schemes for revictualling Paris, starved by the Reign of Terror,
crying for bread, by ships loaded with rice, grain and fish, named the
best merchants to deal with, and on the strength of his services,
secured the long-sought permission to return to France, and there
began that career of success which carried him safely through the
Republic, the Directory, the Empire, the Bourbon restoration and
into the reign of Louis Philippe.

Other Frenchmen had planned a great French colony, — twenty-
four men, mostly young noblemen, had joined in forwarding Joel
Barlow's scheme of a great settlement on the Ohio, — the Scioto Com-
pany was organized, to buy 24,000 acres, — d'Epresmenil, their leader,
lost his life on the guillotine; Marnesia, after a tour through America,
returned to France, and with Lally Tollendal, Mounier and Malouet,
lost touch with their colony in the midst of the great events in their
own countrv.

191 1-] ROSENGARTEN— MOREAU de SAINT MERY. 173

One of Moreau de St. ]\Iery's friends and visitors, Rochefoucauld
Liancourt, wrote an account of the prisons of Philadelphia, which
was printed by Moreau in French and in English in Philadelphia,
(he was the translator), and later it was published in Paris, and in
Dutch in Holland, and later still was made part of one of his six
volumes describing his travels in the United States.

Rochefoucauld spent four years in the United States and describes
in great detail his experiences in the northwest and north, in Canada,
in Maine, in the south, and in New York, New Jersey and Penn-
sylvania.

Talleyrand from Philadelphia wrote to Mme. de Genlis. " Roche-
foucauld is here, making notes, asking information, writing, and
more a questioner than Sterne's curious traveller ; he wants to see
and know everything," in his eager search for the truth. He met
Knox, Sullivan, Jefferson, John Adams, Priestley, Livingston and
Kosciusko. He appealed to Washington to intercede for the release
of Lafayette from Olmutz. His inquiries included politics, consti-
tutions, judicial organizations, army, agriculture, industries, statis-
tics, charities, education. In Georgia he studied cotton and indigo
plantations ; he condemned slavery and argued for the education of
the negroes to prepare them for freedom ; in Niagara and the great
forests he foresaw the sources of future industries. He established
in France on his return societies like the Pennsylvania Prison So-
ciety, and took home much that he had learned in the L^nited States,
which he introduced in France, useful reforms that made him a real
philanthropist.

Another French settler in or near Philadelphia, Pierre Legaux,
was elected a member of the American Philosophical Society in
1787. A Counsellor of Parliament, a member of the Academy of
Arts and Sciences and of several foreign academies, employed in the
French West Indies, he came to Philadelphia about 1786 and made
his mark as a representative of French culture and scientific ability
and by his charm of manner. He bought land on the Schuylkill near
Conshohocken and planted vineyards. Washington and Mifflin and
other notable men visited them and approved his enterprise. Jeft'er-
son. Genet. Brissot, x\udubon, Wistar, were among those whose visits

174 ROSENGARTEN— MOREAU de SAINT MERY. [April 20,

and encouragement he recorded in his diary. He tried to get Jeffer-
son to recommend to Congress protection for his infant industry.
In 1791 he offered his country house to Washington as a home during
the session of Congress and " hoped the country which owes its
Hberty to your wisdom and miUtary talent will owe her wine to
your generosity."

In 1793 the Legislature of Pennsylvania chartered a company to
promote the cultivation of vines, with a capital of $20,000 in $2
shares; in 1800 the stock was fixed by a law passed by the Legisla-
ture at $1 a share down, and the balance of the $20 in easy instal-
ments. Later he advertised that apprentices, black or white, would
be received, with terms of payment, and the promise of a gift of
vines that they could take home and start the industry wherever they
lived. In 1802 the company received its charter and organized.
Among the stockholders were Thomas McKean, Robert Morris,
Genet, Duponceau, Stephen Girard, Alexander Hamilton, Aaron
Burr, Jared Ingersoll, Muhlenberg, Bartram and other notable people
of the 385 subscribers to the stock of the Pennsylvania Vine Co.
Legaux was elected superintendent at a salary of $600 a year with
residence and living at the farm. Expenses soon outran receipts, the
managers quarreled with Legaux, litigation brought ruin, and he,
harassed, worried, disappointed, became a mere servant where he
had once been a genial host, finally succumbed and broken in spirit
died in 1827, and was buried at Barren Hill. Thus sadly closed
another one of the frequent failures of French enterprises in the
L'nited States.^

Moreau de St. Mery kept a journal, cited by Pichot in his " Souve-
nirs intimes de Talleyrand," in which he speaks of Talleyrand's
frequent visits to his book store, meeting there N^oailles, Rochefou-
cauld, Omer Talon, Volney and others less famous.

While the host dined meagerly on rice and milk cooked in his
store, Talleyrand enjoyed drinking his own old Madeira, and was
the life of the party. When Blacon called him monseigneur all
the company burst into a hearty laugh. Talleyrand urged Napo-
leon to erect a statue of Washington in Paris and to give France the

'^Philadelphia Press, September g, 1899, article by Samuel Gordon Smythe.

19".] ROSENGARTEN— MOREAU de SAINT MERY. 175

same perfect religious freedom that he saw practiced in the United
States and he also advised the sale of Louisiana to the United
States as a method of strengthening the ties between the two countries.

One would like to see the journal kept by Moreau de St. Mery
during his residence in Philadelphia. Did he in his palmy davs as
a member of the Council of State under the Empire or in the time
of his modest clerkship in the Marine Department, meet his old
visitors at his book store in Philadelphia, Louis Philippe, Talley-
rand and Rochefoucauld and A'olney and the other exiles now re-
stored to their old prosperity, and did they recall the meetings of the
American Philosophical Society and their attendance and share in
them? His large collection of historical papers, now rescued from
oblivion by calendars by and for the American students of historv,
perpetuates his name and memory and services, more than do the
volumes he wrote and printed and published at his book store at
Front and Walnut Streets.

The latest historian of the French Revolution, Aulard, frequently
mentions Moreau de St. Mery and his share in it. and refers to the
collection of historical documents. His name does not figure in Dr.
^Mitchell's capital novel, "The Red Cit}-," with its picturesque account
of the French exiles living here in the closing years of the eighteenth
century, nor in Kipling's picturesque story of Philadelphia at that
time. x\ll the more reason therefore for an attempt to recall the
memory of the French exiles who were members of the American
Philosophical Society and especially of that one who figures most
often and !;.:st usefully in its records of that time, ^loreau de St.
Mery.

Of the other French exiles during their residence in Philadelphia,
there is occasional mention, as for instance in Talle}Tand's " Me-
moirs." His two papers on the L'nited States and the relations
between France and this countr_\-, read before the French Institute,
were no doubt largely inspired by what he heard at the meetings of
the American Philosophical Society, and his share in the sale of
Louisiana to the Lmited States helped to secure that vast territory
for the future growth of the young republic and its ultimate great
development.

176 ROSENGARTEN— MOREAU de SAINT MERY. [April 20.

In tlie report of M. E. Richard on the ]\Ioreau de St. Alery collec-
tion, printed in the supplement to Dr. Brymner's Report on Cana-
dian Archives for 1899 (Ottawa, 1901 ), he says it was stored in the
archives of the Marine at Versailles up to 1887, then removed to the
Ministere des Colonies, and stored in the attic of the Louvre. They
were then fearful of the great risk of fire, but were considering the
removal to other quarters.

In the reports of 1883-85 and 1887, mention is made of 287
volumes in the collection of Moreau de St. Mery, some forty of which
relate to Canada, others to Louisiana and the French islands of
America. These belonged formerly to the Colonial Archives of the
Marine ; of the collection headed Moreau de St. Mery seventeen
volumes contain description, etc., of the colonies, including a series of
memorials on Canada, 3 volumes are on the religious missions of
Canada, 12 volumes on Newfoundland, 12 volumes containing royal
instructions to governors, and decrees relating to Canada, 119
registers on Canada, Acadia, etc., 6 volumes on civil status of

o

Canada. 34 volumes on Louisbourg ; an analysis was made of 17
volumes of the Moreau de St. Mery collection for the Canadian
Archives.

It is open to the objection that " there is no strict order followed
in the compilation ; it contains but a limited number of documents,
or even extracts from documents. It is difiicult to understand the
dominant idea of this collection."

This collection is. nevertheless, most valuable, for it contains a
consiclerable number of important papers, both transcripts and origi-
nals, not to be found elsewhere.

On p. 5 of Richard's Report, in a footnote, it is said Moreau de St.
Mery, born in Martinique in 1750, studied law in Paris and practiced
in St. Domingo, where he became a member of the Superior Council
of the Island. Entrusted by Louis X\T. with the compiling of a
colonial code, he published in Paris " Les Lois et Constitutions des
Colonies Frangaises de TAmerique sous le Vent." Representing
Martinique in the Constituent Assembly, he drafted the report of the
Committee on the Colonies. Forced by political events to leave
France, he fled to Philadelphia, where he remained from 1793 to

^911-] ROSENGARTEN— MOREAU de SAINT MERY. 177

1798, employing himself as a bookseller and publisher. He there
published his " Description de la partie Espagnole de St. Domingue,"
which he signed " Moreau de St. Mery, member of the Philosophical
Society of Phila." He also translated or edited foreign works, and
among them A'anBraam's " \'oyage to China." Having returned to
France on the 18 Brumaire, he was, through his relationship with
Josephine de Beauharnais, appointed in 1800 to the position of
Historiographer of the ]\Iarine. Napoleon appointed him to the
Council of State, in view of his knowledge of colonial affairs. In
1802 he was administrator of Parma and Guastalla, but lost favor
and was removed in 1806. He died poor and in receipt of a pension
from Louis XA'HI.

While entrusted with a mission in St. Domingo, as publisher in
Philadelphia and historiographer in Paris, we find him everywhere
an observer and a worker, taking notes on everything. His collec-
tion of manuscripts comprises 287 large volumes, and was purchased
by the state after his death, that is to say the government had to
pay not only for the transcripts he had caused to be made, but even
for the originals he had appropriated.

Persons who take a special interest in the social and religious
condition of the country, the disputes and conflicts between the
authorities will find in the Moreau de St. Alery collection far more
than they could find in any other series.

That Moreau de St. Mery did a good work in preserving and
making his collection is shown by the statement (in Richard's Re-
port, p. 8, etc.), that the Archives of the Ministry of Marine were
so utterly neglected that the precious papers were used during five
weeks of the winter in 1793, as fuel to feed the stoves of the post
of the Garde Xationale in the building where the archives were kept,
and in 1830 an employee gave up the archives to pillage and sold,
by weight for his own profit, whole piles of documents, bought by
autograph collectors.

Thanks to the suggestion of Prof. Cleveland Abbe, I found in the
Monthly JVcathcr Rcvicz^' for February, 1906 (Washington. Weather
Bureau, 1907 ), at pp. 64, etc., in a notice by C. Fitzhugh Talman of the
U. S. Weather Bureau, the following : " Foremost among the early

178 ROSENGARTEN— MOREAU de SAINT MERY. [April 20,

writers upon the island of Santo Domingo, was ]\Iederic Louis Elie
Moreau de St. Mery, who produced three vokmiinous works upon
the French possessions in the West Indies. Born at Fort Royal,
Martinique, in 1750, he passed his early manhood in Haiti, and
settled at the then capitol of the colony. Cap Franqais (now Cap
Haitien). He held an important ofifice in the administration of the
colony, and also, under a commission from Louis i6th, travelled ex-
tensively through the French West Indies, collecting material for a
work published in 1785, under the title " Lois et Constitutions des
Colonies Francaises de I'Amerique sous le vent, de 1550 a 1785."
Returning to France he took an active part in the French Revolution,
until obliged to flee from his political enemies to the L'nited States.
It was during a period of exile in the latter country that he published
two works descriptive of the island of Santo Domingo, one devoted
to the Spanish part of the island, the other to the French part. Pub-
lished by himself in Philadelphia in 1797. it was republished in Paris
in 1875 by ]\Iorgand in 2 vols. 8vo. It is to this day regarded by
the Haitians as the highest authority upon the physical geography
of their country and is quoted at length in the latest Haitian gazeteer
(Ronzier Die. geog. et admin, d. Haiti, Paris, 1899). Mr. Talman
reproduces St. Mery's chart of the Island, and a full abstract of his
description of its meteorology.

Moreau de St. Mery was active in the Philadelphia Society of Cap
Franqais, and in the Library of the American Philosophical Society
there is the ist vol. of its Proceedings, — no 2nd or later volume is
preserved,— it shows that Aloreau de St. Alery was the leading
spirit in its activities. That his meteorological observations of San
Domingo during his residence there in the eigliteenth century, should
be found of value today, is but another proof of his useful activity.
His chief monument however is his collection, bearing his name, of
original documents on the French in America, and by it he is
now made known to students in the pages of Aulard. Brymner,
Thwaites and other historians.

THE NEW HISTORY.

Bv JAMES HARVEY ROBINSON.
{Read April 22, 1911.)

I propose to discuss in this paper the vakie of historical study.
The question has long haunted me and certainly merits a more care-
ful consideration than it has, so far as I can discover, hitherto re-
ceived. It will be impossible to do more here than to analyze the
problem and briefly state the general conclusions which that analysis
suggests.

The older traditional type of historical writing was narrative in
character. Its chief aim was to tell a tale or story by setting forth a
succession of events and introducing the prominent actors who par-
ticipated in them. It was a branch of polite literature, competing
with the drama and fiction, from which, indeed, it differed often
only in the limitations which the writer was supposed to place upon
his fancy. As Professor .McAlaster has recently said: "It was by
no mere accident that ]\Iotley began his literary career with a novel
called " Merry-Mount," and Parkman his with " Vassall Morton.''
These bespoke their type of mind. The things that would interest
them in history would be, not the great masses of toiling men, not the
silent revolutions by which nations pass from barbarism to civiliza-
tion, from ignorance to knowledge, from poverty to wealth, from
feebleness to power, but the striking figures of history, great kings and
queens, the leaders of armies, men renowned for statescraft, and the
dramatic incidents in the life of nations. Each must have his hero
and his villain, his plots, conspiracies and bloody wars. Just as
Froude had his Henry VIII. ; just as ]Macaulay had his William HI.,
Carlyle his Robespierre and Cromwell, and Thiers his Xapoleon, so
Motley had his William of Orange and Philip of Spain ; Prescott
his Cortez, Pizarro, Ferdinand and Isabella ; and Parkman his Pon-
tiac, Frontenac and La Salle. History as viewed by writers of this

PROC. AMER. PHIL. SOC., 1., I99 L, PRINTED JUNE 27, I9II.

179

180 ROBINSON— THE NEW HISTORY. [April 22,

school is a series of dramas in each of which a few great men per-
form the leading parts and use the rest of mankind as their instru-
ments."^ The commonly accepted definition of history was long,
" a record of past events " and these, naturally, the most startling
and romantic and the best adapted for efifective literary presentation.
Dovibtless there was some serious effort to describe conditions and
institutions, since they formed the necessary setting for the events
and anecdotes ; sometimes they would even be assigned a place on
their own intrinsic merits ; but what may be called the epic ideal of
history prevailed until perhaps fifty or sixty years ago when, owing
to the influence of the modern scientific spirit, a very fundamental
revolution became apparent.

Now let us review, by way of preliminary, what were deemed
the advantages of the study of history of this older type. Lord
Bolingbroke in his " Letters on the Study of History," written about
1737, says: ''An application to any study that tends neither to make
us better men and better citizens, is at best but a specious and in-
genious sort of idleness; . . . and the knowledge we acquire by it is
a creditable kind of ignorance, nothing more. This creditable kind
of ignorance is, in my opinion, the whole benefit which the generality
of men, even the most learned, reap from the study of history : and
vet the study of history seems to me of all others the most proper to
train us up to private and public virtue." History, he quite prop-
erly says, is read by most people as a form of amusement, as they
might play at cards. Some devote themselves to history in order
to adorn their conversation with historical allusions, — and the argu-
ment is still current that one should know enough of the past to
understand literary references to' noteworthy events and persons.
The less imaginative scholar, Bolingbroke complains, satisfies him-
self with making fair copies of foul manuscripts and explaining hard
words for the benefit of others, or with constructing more or less
fantastic chronologies based upon very insecure data. Over against
these Bolingbroke places those who have perceived that history is
after all only "philosophy teaching by example." For "the exam-

' " The Present State of Historical Writing in America," reprinted from
the Proceedings of the American Antiquarian Society for October, 1910;
Worcester, 1910, p. 18.

I9II.] ROBINSON— THE NEW HISTORY. 181

pies which we find in history, improved by the hvely descriptions
and the just explanations or censures of historians/' will, he believes,
have a much better and more permanent effect than declamation, or
the " dry ethics of mere philosophy." ^Moreover, to summarize his
argument, we can by the study of history enjoy in a short time a
wide range of experience at the expense of other men and without
risk to ourselves. History enables us " to live with the men who
lived before us, and we inhabit countries that we never saw. Place
is enlarged, and time prolonged in this manner : so that the man
who applies himself early to the study of history may acquire in a
few years, and before he sets foot in the world, not only a more
extended knowledge of mankind but the experience of more cen-
turies than any of the patriarchs saw\" Our own personal expe-
rience is doubly defective ; we are born too late to see the beginning,
and we die too soon to see the end of many things. History sup-
plies in a large measure these defects.

There is of course little originality in Bolingbroke's plea for his-
tory's usefulness in makihg wiser and better men and citizens.
Polybios had seen in history a guide for statesmen and military
commanders ; and the hope that the conspicuous moral victories and
defeats of the past would serve to arouse virtue and discourage vice
has been urged by innumerable chroniclers as the main justification
of their enterprises. To-day, however, one would rarely find a
historical student who would venture to recommend statesmen,
warriors and moralists to place any confidence whatsoever in histor-
ical analogies and warnings, for the supposed analogies usually
prove illusive on inspection and the warnings, impertinent. Whether
or no Napoleon was ever able to make any practical use in his own
campaigns of the accounts he had read of those of Alexander and
Csesar, it is quite certain that Admiral Togo would have derived no
useful hints from Nelson's tactics at Alexandria or Trafalgar. Our
situation is so novel that it would seem as if political and military
precedents of even a century ago could have no possible value. As
for our present " anxious morality," as Maeterlinck calls it, it seems
equally clear that the sinful extravagances of Sardanapalus and
Nero, and the conspicuous public virtue of Aristides and the Horatii,
are alike impotent to promote it.

182 ROBINSON— THE NEW HISTORY. [April 22,

111 addition to the supposed uses of history mentioned by BoHng-
broke there was the possibihty of tracing the ways of God to man.
Augustine had furnished the first great example of this type of nar-
rative in his " City of God " and thereafter history had very com-
monly been summoned to the support of Christian theology. Bos-
suet, writing for the Dauphin in the latter part of the seventeenth
century, says : " Mais souvenez-vous, Monseigneur, que ce long en-
chainement des causes particulieres qui font et defont les empires
depend des ordres secrets de la Providence. Dieu tient du plus haut
des cieux les renes de tons les royaumes ; il a tous les coeurs en sa
main ; tantot il retient les passions, tantot il leur lache la bride, et
par la il remue tout le genre humain. Veut-il faire des conque-
rants ; il fait marcher I'epouvante devant eux, et il inspire a eux et
a leurs soldats une hardiesse invincible. Veut-il faire des legisla-
teurs ; il leur envoie son esprit de sagesse et de prevoyance ; il leur
fait prevenir les maux qui menacent les etats, et poser les fonde-
ments de la tranquillite publique. II connoit la sagesse humaine,
toujours courte par quelque endroit; il Teclaire, il etend ses vues, et
puis I'abandonne a ses ignorances ; il I'aveugle, il la precipite, il la
confond par elle-meme ; elle s'enveloppe, elle s'embarrasse dans ses
propres subtilites, et ses precautions lui sont un piege. Dieu exerce
par ce moyen ses redoutables jugements, selon les regies de sa justice
toujours infallible."- It was assumed by such writers as Bossuet
that in spite of the confessedly secret and mysterious character of
God's dispensations it was nevertheless quite possible for the skilled
theologian to trace them with edifying confidence and interpret them
as divine sanctions and disapprovals, blessings and punishments,
trials and encouragements. For various reasons, which it is unnec-
essary to review here, this particular method of dealing with the past
and deriving useful lessons from it finds few educated defenders at
the present day.

In the eighteenth century a considerable number of " philosophies
of history " appeared and enjoyed great popularity. They were the
outcome of a desire to seize and explain the general trend of man's
past. Of course this had been the purpose of Augustine and Bossuet

-"Discours siir I'histoire universelle," concluding chapter.

191 1] ROBINSON— THE NEW HISTORY. 183

but \'oltaire devoted his " Philosophie de I'histoire " (1765) mainly
to discrediting religion as commonly accepted ; and instead of offer-
ing any particular theory of the past he satisfied himself with pick-
ing out what he calls Ics vcrites utiles. He addresses Madame du
Chatelet in the opening of his " Essai sur les ]Moeurs et I'esprit des
nations " as follows : \'ous ne cherchez dans cette immensite que ce
qui merite d'etre connu de vous ; I'esprit, les moeurs, les usages des
nations principales, appuyes des faits qu'il n'est pas permis d'ignorer.
Le but de ce travail n'est pas de savoir en quelle annee un prince
indigne d'etre connu succeda a un prince barbare chez une nation
grossiere. Si Ton pouvait avoir le malheur de mettre dans sa tete
la suite chronologique de toutes les dynasties, on ne saurait que des
mots. Autant il faut connaitre les grandes actions des souverains
qui ont rendu leurs peuples meilleurs et plus heureux, autant on
pent ignorer le vulgaire des rois, qui ne pourrait que charger la
memoire. . . . Dans tons ces recueils immenses qu'on ne peut em-
brasser, il faut se borner et choisir. C'est un vaste magazin ou vous
prendrez ce qui est a votre usage.'' Voltaire's reactions on the past
were naturally just what might have been expected from his attitude
toward his own times. He drew from " le vaste magazin " those
things that he needed for his great campaign, and in this he did well,
however uncritical his criticism may at times seem to a modern
historical student.

Herder in his little work, " Auch eine Philosophie der Geschichte
zur Bildung der Alenschheit. Beitrag zur vielen Beitragen des Jahr-
hunderts " (1774), condemns the general lightheartedness and super-
ficiality of A'oltaire and other contemporary writers who were, he
thought, vainly attempting to squeeze the story of the universe and
man into their puny philosophic categories. Ten years later he
wrote his larger work, " Ideen zur Geschichte der ]^Ienschheit," in
which he strove to give some ideal unity and order to the vast
historic process, beginning with a consideration of the place of the
earth among the other heavenly bodies, and of man's relations to the
vegetable and animal kingdoms. " H'," he says, " there be a god in
nature, there is in history too; for man is himself a part of creation,
and in his wildest extravagances and passions must obey laws not

^ "Avant propos."

184 ROBINSON— THE NEW HISTORY. [April 22,

less excellent and beautiful than those by which all the celestial
bodies move. Now as I am persuaded that man is capable of know-
ing, and destined to attain the knowledge of, everything that he ought
to know, I step freely and confidently from the tumultuous scenes
through which we have been wandering to inspect the beautiful and
sublime laws of nature by which they have been governed." Hu-
manity is the end of human nature, he held, and the human race
is destined to proceed through various degrees of civilization in var-
ious mutations; but the permanency of its welfare is founded solely
and essentially on reason and justice. But it is a natural law that
'* if a being or system of beings be forced out of the permanent
position of its truth, goodness and beauty it will again approach it
by its internal powers, either in vibrations or in an asymptote, as
out of this state it finds no stability."* Herder formulates from
time to time a considerable number of other *' laws " which he believes
emerge from the confusion of the past. Whatever we may think of
these " laws "" he constantly astonishes the modern reader not only
by his penetrating criticism of the prevailing philosophy of his time
but by flashes of deep historical insight. He is clearly enough the
forerunner of the "Romantic" tendency that culminated in Hegel's
celebrated " Philosophy of History " in which the successive migra-
tions and national incarnations of the JJ'cltgcist are traced to its
final and highest medium of expression, the German people.

These genial speculations of the philosophers of history rested
usually upon no very careful study of historical sources and their
conclusions seem to us now very hazardous, even if we grant the cor-
rectness of the data upon which they relied. It was inevitable that
the historical students who, about the middle of the nineteenth cen-
tury, commenced to feel the influence of the general scientific spirit
of the period, should begin to look very sourly upon the earlier
attempts to bring order and beauty out of a mass of historic asser-
tions which were so commonly either erroneous or unproved, and to
establish laws for events which one could not be sure had ever hap-
pened. The reaction against the dreams of the philosophers of his-
tory was, and is still, very clear. What may be called, for conveni-
ence, the "scientific" modern school of historians believe that history,

* Opening sections of Book XV.

191 1.] ROBINSON— THE NEW HISTORY. 185

like all other forms of scientific research, should be pursued first and
foremost for its own sake. The facts must be verified and classified
by the expert, without regard to any possible bearing which his
discoveries may have upon our attitude toward life and the proper
way of conducting it. Attempts to draw lessons from the past have,
it is plausibly maintained, produced so reckless a disregard of scien-
tific accuracy and criticism, that the prudent, historian will coniine
himself to determining " how it really was "-—an absorbing and deli-
cate task which will tax his best powers.

Along with more exacting criticism and the repudiation of super-
natural considerations and explanations came a revulsion against the
older epic or dramatic interest in the past. The essential interest
and importance of the normal and homely elements in human
life became apparent. The scientific historian no longer dwells
by preference on the heroic, spectacular, and romantic episodes,
but strives to reconstruct past conditions. This last point is of such
importance that we must stop over it a moment. History is not
infrequently still defined as a record of past events and the public
still expect from the historian a story of the past. But the conscien-
tious historian has come to realize that he cannot aspire to be a good
story teller for the simple reason that if he tells no more than he
has good reasons for believing to be true his story is usually very
fragmentary and uncertain. Fiction and drama are perfectly free
to conceive and adjust detail so as to meet the demands of art, but
the historian should always be conscious of the rigid limitations
placed upon him. If he confines himself to an honest and critical
statement of a series of events as described in his sources it is usu-
ally too deficient in vivid authentic detail to make a presentable
story. The historian is coming to see that his task is essentially dif-
ferent from that of the man of letters. His place is among the scien-
tists. He is at liberty to use only his scientific imagination, which is
surely different from a literary imagination. It is his business to
make those contributions to our general understanding of mankind
in the past which his training in the investigation of the records of
past human events especially fit him to make. He esteems the
events he finds recorded not for their dramatic interest but for the
light that they cast on the normal and prevalent conditions which

186 ROBINSON— THE NEW HISTORY. [April 22,

gave rise to them. It makes no difiference how dry a chronicle may
be if the occurrences that it reports can be brought into some assign-
able relation with the more or less permanent habits and environment
of a particular people or person. If it be the chief function of his-
tory to show how things come about — and something will be said of
this matter later — -then events become for the historian first and
foremost evidence of general conditions and changes affecting con-
siderable numbers of people. In this respect history is only fol-
lowing the example set by the older natural sciences — zoology dwells
on general principles not on exceptional and startling creatures or
on the lessons which their habits suggest for man. Mathematics
no longer lingers over the mystic qualities of numbers, nor does the
astronomer seek to read our personal fate in the positions of the
planets. Scientific truth has shown itself able to compete with fiction,
and there appears to be endless fascination for the mind in the con-
templation of what former ages would have regarded as the most
vulgar and tiresome commonplace.

In addition to the characteristics of modern history just enum-
erated two great historical discoveries of the latter half of the
nineteenth century have served still further to revolutionize our atti-
tude towards the past of mankind. Curiously enough neither of
these discoveries are due to historians. I refer to the well substan-
tiated fact tliat man is sprung from the lower animals, and secondly,
that he has in all probability been sojourning on the globe for sev-
eral hundreds of thousands of years. These discoveries have grave-
ly influenced all speculations in regard to the earlier history of our race
and have placed the so-called " historical period " in a new setting.
The historian no longer believes that he knows anything about man
from the very first but realizes that what is commonly called history
comprises only a very recent and very brief period in man's develop-
ment. All history is modern history from the standpoint of pre-
historic anthropology. Lastly, a group of anthropological, psycho-
logical and social sciences have made their appearance during the
past fifty years which are furnishing the historian with many new
notions about man and are disabusing his mind of many old misap-
prehensions in regard to races, religion, social organization, and the
psychology of progress. The older historians used such words as

191 1.] ROBINSON— THE NEW HISTORY. 187

race, human nature, culture, religion, church, people. Renaissance,
Reformation. Revolution, almost as if they were the names of ani-
mistic forces. These terms must be analyzed and reinterpreted in
the light of the newer sciences of man.

The kind of history, accordingly, the practical value of which we
shall attempt roughly to estimate, and which for convenience sake
we may call the " new " history, is scientific in its methods, exact-
ing in regard to the inferences it makes from its material ; it rejects
supernatural explanations and an anthropocentric conception of the
universe ; it studies by preference the normal and long enduring
rather than the transient and exceptional ; it accepts the descent of
man from the lower animals, many of whose psychological traits he
shares ; it recognizes that man has lived on the earth for not merely
five thousand but perhaps for five hundred thousand vears ; it avails
itself, when fully abreast of the time, of all the suggestions and criti-
cisms that are constantly being contributed by the newly developed
sciences of anthropolog}', comparative, social and functional psychol-
ogy, comparative religion, etc.^ So much for the attitude of mind
of the modern historian who realizes the changes which have over-
taken his subject during the past fifty or sixty years.

But if "history" be re-defined as no longer a record of past
events but the attempt to describe with all possible scientific pre-
cision what we know of the nature and conditions of human institu-
tions, conduct and thought in the past, does not the term become
hopelessly vague — as vague at least as the term natural science?
Does not the historian sacrifice his only obvious clue to the past
when he gives up tracing a succession of conspicuous events, for only
these lend themselves to an obvious and orderly selection and
arrangement? Every human interest and achievement has its his-
tory, every accomplished, and every vain dream. It would seem as
if every attempt to deal with the past must necessarily imply an
arbitrary selection dictated by the investigator's particular humor
and tastes. This situation is still disguised by the continued pop-
ularity of a standard variety of history, mainly political, dynastic
and military, transmitted to us from the past and taught in our

'See "The Relation of History to the Newer Sciences of Man" in The
Journal for Philosophy, Psychology and Scientific Methods, Vol. VIIL, No.
6, March, iQii, where I have elaborated this point.

188 ROBINSON— THE NEW HISTORY. [April 22,

schools and colleges and presented to the adult public in many well
known older and newer treatises.

In order to appreciate the arbitrary nature of the selection of
historic facts offered in these standard text books and treatises, let
us suppose that a half dozen alert and well trained minds had never
happened to be biased by the study of anv outline of history and had
by some happy and incredible fortune never perused a " standard "
historical work. Let us suppose that they had nevertheless learned
a good deal about the past of mankind directly from the vast range
of sources that we now possess, both literary and archaeological.
Lastly, let us assume that they were all called upon to prepare inde-
pendently a so-called general history, suitable for use in the higher
schools. They would speedily discover that there was no single
obvious rule for determining what should be included in their review
of the past. Having no tradition to guide them, each would select
what he deemed most important for the young to know of the past.
Writing in the twentieth century, they would all be deeply influenced
by the interests and problems of the day. Battles and sieges and the
courts of kings would scarcely appeal to them. Probably it would
occur to none of them to mention the battle of Issus, the Samnite
wars, the siege of Numantia by the Romans, the advent of Hadrian,
the Italian enterprises of Otto I., the six wives of Henry VIII. or the
invasion of Holland by Louis XI\ . It is tolerably safe to assume
that none of these events, which are recorded in practically all of our
manuals to-day, would be considered by any one of our writers as
he thought over all that man had done, and thought, and suffered,
and dreamed, through thousands of years. All of them would agree
that what men had known of the world in which they lived, or had
thought to be their duty, or what they made with their hands, or the
nature and style of their buildings, public and private, would any of
them be far more valuable to rehearse than the names of their
rulers and the conflicts in which they engaged. Each writer would
accordingly go his own way. He would look back on the past for
explanations of what he found most interesting in the present and
would endeavor to place his readers in a position to participate
intelligently in the life of their own time. The six manuals when
completed would not only differ greatly from one another but would

igii.] ROBINSON— THE NEW HISTORY. 189

have little resemblance to the fable convenne which is currently ac-
cepted as embodying the elements of history.

History in its broadest sense, is, in short, nothing less than the
experiences of our race, so far as we can determine or surmise them.
And what uses are we to make of the experiences of the race? The
same kind of use that we make of our own individual history. We
may question it as we question our memory of our personal acts,
situations and past ideals. But those things that we recall from the
superabundant fund of our own experiences vary continually with our
moods and preoccupations. We instinctively adjust our recollec-
tions to our immediate needs and aspirations and ask from the past
light on the particular problems that face us. Just as our individual
history is thus not immutable but owes its value to its adap-
tability, so with the history of mankind. As Maeterlinck has beauti-
fully said, with increased insight, ''historic facts which seem to
be graven forever on the stone and bronze of the past will assume
an entirely different aspect, will return to life and leap into move-
ment, bringing vaster and more courageous counsels." History is
then not fixed and reducible to outlines and formulas but it is
ever alive and ever changing, and it will, if we will but permit it,
illuminate and explain our lives as nothing else can do. For our
lives, are made up almost altogether of the past and each age should
be free to select from the annals of the past those matters which
have a bearing on the matters it has specially at heart.

K we test our personal knowledge of history by its usefulness
to us, in giving us a better grasp on the present and a clearer notion
of our place in the development of mankind, we shall perceive forth-
with that a great part of what we have learned from historical works
has entirely escaped our memory, for the simple reason that we have
never had the least excuse for recollecting it. The career of Ethel-
red the Unready, the battle of Poitiers, and the negotiations leading up
to the treaty of Nimwegen are for most of us forgotten formula, no
more helpful, except in a remote contingency, than the logarithm
of the number 57. The ideal history for each of us would be those
facts of past human experience to which we should have recourse
oftenest to our endeavors to understand ourselves and our fellows.
No one account would meet the needs of all. but all would agree

190 ROBINSON— THE NEW HISTORY. [April 22,

that much of what now passes for the elements of history meet the
needs of none.

It would take too long to attempt an analysis of the value of a
genetic treatment of the elements in our social life. It is perhaps
the greatest single discovery of modern times that we understand a
situation best through its history, and this discovery has revolution-
ized every branch of organic and social science. Indeed we ordi-
narily first get a fairly comprehensive notion of a given phenomenon
by tracing its origin and development, whether it be the human back-
bone, the order of St. ISenedict. the stock exchange, the Wagnerian
opera, or the doctrine of stare decisis. In many cases the knowledge
of the history of an institution not uncommonly gravely affects our
attitude toward it. The United States Senate looks different to
one familiar with the history of the bicameral system and to one
who is not. The Puritan sabbath could never have sustained a
critical historical examination. One's views of democracy, or of the
present laws of property, or of the prevailing economic organization,
can readily be deeply aff'ected by a study of the earlier conditions'
which lie back of present conditions. History has a disintegrating
effect on current prejudices which is as yet scarcely appreciated. It
makes both for understanding and for intellectual emancipation as
nothing else can.

(Jbviously history must be rewritten, or rather, innumerable cur-
rent issues must be given their neglected historic background. Our
present so-called histories do not ordinarily answer the questions we
would naturally and insistently put to them. When we contemplate
the strong demand that women are making for the right to vote, we
ask ourselves how did the men win the vote? The historians we
consult have scarcely asked themselves that question and so do not
answer it. W'e ask how did our courts come to control legislation in
the exceptional and extraordinary manner they do? We look in
vain in most histories for a reply. No one questions the inalienable
right of the historian to interest himself in any phase of the past
that he chooses. It is only to be wished that a greater number of
historians had greater skill in hitting upon those phases of the past
which serve us best in understanding the most vital problems of the
present.

Columbia University.

THE ATOMIC WEIGHT OF VANADIUM DETERMINED

FROM THE LABORATORY WORK OF

EIGHTY YEARS.

Bv DR. GUSTAVUS D. HIXRICHS.
{Read April 21, 1911.)

\'anadium can no longer be considered a rare element. Ferro-
vanadium is produced on a large scale for the manufacture of special
vanadium steels. Strangely enough, it was in a kind of natural
vanadium iron that Sefstrom detected this element eighty years ago.

In 1830, while technical director of the famous iron works at
Taberg in Smaland, Sweden, Sefstrom thought it might be interest-
ing to submit his high quality malleable iron to the Rieman Test
for cold-short iron, notwithstanding the apparent absurdity of such
an undertaking. Accordingly he took one of his bars. On a part
of its bright metallic surface he drew the little circular ridge of
tallow and poured dilute sulphuric acid into the shallow dish thus
formed, expecting, of course, to see no change whatever of the
bright metallic bottom of this improvised dish. But he was
amazed to see that bright bottom instantly turn black while the
shallow dish rapidly filled up with a black powder, exactly as it
does when the iron tested is badly cold-short.

The distinguished disciple of the great Berzelius instantly realized
that this striking contradiction between test and fact was a positive
indication of the presence of a hitherto unknown chemical element.
Accordingly he set about isolating this new element. Working up
quite a number of pounds of his iron, Sefstrom obtained less than a
decigramme of the substance from which the new element was to
be separated. Hence he turned hopefully from the iron to its fresh
slag and found it to yield a much larger per cent, of the black
powder. He now soon succeeded in isolating the new element

191

192 HINRICHS— ATOMIC WEIGHT OF VANADIUM. [April 21,

which, as a good Scandinavian, he named vanadin after \"anadiis,
a designation of Freya, the greatest Goddess in \'alhalla.

Sefstrom had promptly informed his teacher of the discovery
and soon after brought his entire stock of the new element to
Berzelius, requesting him to continue the research for which his
own industrial work and the professorial duties at the Fahlun
JVIontan-School left him neither the leisure nor the facilities. For
a short time Sefstrom worked with Berzelius on the new element in
that famous " Kitchen Laboratory " where Berzelius alone com-
pleted the splendid work of which he published a summary on pp.
99-110 of the "Annual Report" which he presented to the Swedish
Academy of Sciences on March 31, 1831 — exactly eighty years ago.

For almost forty years the element vanadin of Sefstrom and
Berzelius remained undecomposed, but the striking isomorphism
of the mineral vanadinite with the remarkable isomorphic group of
apatite and pyromorphite presented the anomalous condition of the
isomorphism of the element vanadin of Berzelius with the group
PO of apatite and pyromorphite. This anomaly invited further
attempts of the reduction of vanadin in which Roscoe was success-
ful, 1867, proving vanadin to be really the oxide A'aO, in which Va
is the symbol of the present element vanadium of the atomic weight
51. This fully explains the isomorphism of vanadinite containing
the oxide VaO, with pyromorphite, containing the corresponding
oxide PO.

In this first research of Berzelius on vanadium, the old master
already determined the atomic weight of the new element ; for
his value 67 for what we now know to have been VaO gives Va 51.
He devised and used five distinct chemical methods for this atomic
weight determination to which npt one new method has been added
in the eighty years elapsed since that work was done by the great
chemist in his kitchen laboratory. It is a well-authenticated historic
fact, Berzelius not only made atomic weight determinations for
vanadium, but they were as accurate as those made forty years
later by Roscoe, while some were as precise as corresponding
determinations made eighty years later by Prandtl ; besides, not only
Roscoe and Prandtl, but all chemists have done this work bv means

191 1.] HINRICHS— ATOMIC WEIGHT OF VANADIUM. 193

of the methods devised by BerzeHus which he practiced in his
laboratory in 1831.

It is therefore with great astonishment that I read in the first
edition of the " Recalculation " of F. W. Clarke : " Roscoe's determi-
nation of the atomic weight of vanadium was the first to have any
scientific value. The results obtained by BerzeHus . . . were
unquestionably too high, the error being probably due to the presence
of phosphoric acid in the vanadic acid employed."

The same erroneous statement is repeated identically at the
opening of the chapter on vanadium in the succeeding two editions
of the work as may be seen by comparing: p. 183. edition 1882; p.
211, edition 1897. and p. 305. edition 1910.

The only new method, Cjuite recently applied to the determination
of the atomic weight of vanadium, is that of Edgar F. Smith. ^
This admirable method strictly conforms to the Berzelian advice
" to chose such chemical methods for atomic weight determinations
that the final result shall depend as little as possible on the operator's
skill in manipulation."' In my summary of the work of one hundred
years on the determination of the atomic weight of hydrogen- I
have given this great rule of Berzelius. in his own handwriting, from
his " Sjelfbiografiska Anteckningar," published by the Kgl. Svenska
Vetenskapsakademien, 1901, p. 41.

This rule requires to select such chemical reactions in which the
physical and chemical characters of the substances weighed are so
definitely fixed that the unavoidable errors of man and his instru-
ments become negligible quantities. Such is the reaction no. 311
above referred to. Hence the work done by AIcAdam in the labora-
tory and under the direction of Edgar F. Smith has furnished the
highest direct chemical approximation obtainable to the absolute
scientific truth that \'a is 51 exactly. This will appear, we think,
from a careful examination of all the results actually obtained dur-
ing the eighty years from 1831 to 191 1 as plotted in our two dia-
grams no. 730 and no. 731 published with this paper.

The above reference to the presence of phosphoric acid in the

' See Journal Amer. Chcm. Society. 1910, p. 1603. in the December number.
■ In the Revue Generale dc Chimie. 1910, Nos. 22 and 24.

194 HINRICHS— ATOMIC WEIGHT OF VANADIUM. [April 2:.

vanadic acid used by Berzelius reminds us of the homely but sound
scriptural advice habitually given by Berzelius to his disciples : " do
not strain at a gnat while swallowing camels." The phosphoric acid
in the vanadic acid used by Berzelius was detected by Roscoe in the
sample which Berzelius had presented to Faraday ; but the molybdic
reagent necessary for the detection was not known to chemistry in
the year 183 1 when Berzelius did his work on vanadium.

As a matter of fact, Berzelius did not see this gnat; but his
work shows that he did avoid some of the camels that stalk about
the laboratories and which were deglutinated unconsciously forty
and eighty years after Berzelius failed to strain that gnat. The
error-shares due to the oxygen are the fattest and most numerous
of these camels, up to the present day.

Our Method of Reduction.

In order to solve the riddle of the conflicting experimental data
obtained in the chemical laboratories of the world during an entire
century of painstaking work, we have, especially in the last quarter
century, carried on special researches on the proper mathematical
reduction of this kind of laboratory work.

The final results of this extended research are briefly sum-
marized in five tables of wdiich two only have thus far been pub-
lished. Our work itself has been published in the following books
and special papers :

" The True Atomic Weights," St. Louis, 1894, xvi -\- 256 pp.,
8vo, with 7 plates and many illustrations. Dedicated to Berthelot.

"The Absolute Atomic Weights." St. Louis, 1901, xvi -|- 304 pp.,
8vo, with portrait of Berzelius and three plates,

" The Proximate Constituents of the Chemical Elements," St.
Louis, 1904, with 7 portraits, many plates, 112 pp. text, 8vo. This
is an inductive treatise of the subject.

The " Cinquantenaire," 1910, gives some historical data, copies
of older papers, letters in fac-simile and " Fragments inedits " with
fine diagrams ; 66 pp., 4to, with plates and portraits.

" Notes " published in the Coinptcs Rcndiis of the Academy of
Sciences of Paris from 1873 to the present, almost sixty in number.

191 1.] HIXRICHS— ATOMIC WEIGHT OF VANADIUM. 195

forming a volume of over 200 pp. 4to. The first, and in fact the
greater number of the " Xotes," were presented by Berthelot ; others
were presented by Messrs. Gautier, Lemoine, Haller, Gernez, and
other academicians.

In the Monitcur Sciciitifiquc. from 1906 to 1909 more than a
dozen longer articles have appeared with many diagrams. The
first two tables above referred to are found in the November num-
ber for 1901. with discussions, pp. 731—744.

The papers were originally written in four languages : Danish,
German, English and French. To these papers the reader may be
referred by the Cinquantenaire and the list in the Prox. Constit.
The results obtained, being in conflict with the dominant chemical
school, have not been widely circulated except as adopted children.

For these reasons it is necessary here to give enough of the
details of the finally worked out practical method of reduction to
enable the reader to repeat all the calculations required, so that he
can verify the results given.

It will then be seen that the final method is quite simple ; the
difficulty was to get this method.

Let a represent the absolute atomic z^right of any chemical ele-
ment, that is the whole or round number (h or even ^) which the
experiments indicate to be near the true atomic zveight A, which
exactly to determine is the object of the reduction. The unit
adopted is exactly yV of carbon-diamond which is practically iden-
tical with iV of that of oxygen.'

The departure of the true atomic weight from the absolute
atomic weight we designate by the Greek letter epsilon (e) ; that is:
A^a-\-e. This departure, as a matter of fact, is found to be a
small fraction of the unit ; we invariably express it in thousandths
of that unit.

This departure — in units of the third decimal — is really our new
variable, the quantity to be determined. This apparently insignifi-
cant matter of form is really of the greatest importance. For this
new variable all products and powers become negligible quantities

^Comptes Rendus, 117, p. 1075, 1893.

PROC. AMER. PH[L. SOC. , L, I99 M, PRINTED JUNE 26, I9II.

196 HINRICHS— ATOMIC WEIGHT OF VANADIUM. [Apm 21,

in our necessary calculati(3ns, because the departures are small
quantities ; hence, all calculations, even involving the most complex
mathematical functions, are reduced to the simple rule of three and
carried out by proportional parts. The importance will soon be
recognized by the practice of the method.

The actual laboratory z^'ork consists essentially in the deter-
mination of tii'o weights which we denote by p and q and which rep-
resent chemically pure compounds of the formula P and 0 respec-
tively. The necessary condition is that the weight p has been com-
pletely changed into q according to the exact formulae P and Q by
means of a suitable chcuiical reaction. Of such reactions we have
tabulated and examined over three hundred that have been actually
used for atomic weight determinations. We designate each such
reaction by a number for ready reference. This number is simply
marking their place in our table above referred to ; it is arbitrary
but a practical necessity. We have already above referred to the
remarkable chemical reaction, recently applied in the Harrison Labo-
ratory of the University of Pennsylvania as reaction no. 311.

Substituting the absolute atomic weights a for the chemical sym-
bols in the formulae of the two compounds P and 0, we can readily
calculate the value of the quotient P/Q which we call the atomic
ratio R and calculate the same to five decimals, the limit of precision
today. On the following pages, giving the data for the chemical
reactions that have been used for the determination of the atomic
weight of vanadium there will be found examples of these and of
all other processes, to which we request the reader to turn as new
operations are defined.

On the other hand, the weights actually taken in the laboratory
and designated by the letters p and q will give the analytical ratio r
which w^e calculate also to five decimal places. The analytical ratios
determined by the different experiments with the same two com-
pounds P and 0 will give hardly any identical values of r ; we notice
their extreme values, that is the maximum and the minimum in any
given series of determinations made in the same manner with the
identical material. The differance between the greatest and the
least value of the analytical ratios of a series is the range of that
series. This characterizes the concordance of the different deter-

191 1.] HIXRICHS— ATOMIC WEIGHT OF VANADIUM. 197

minations of any series without introducing any false theoretical
notion, as is done by the calculation of the so-called probable error
of the mean. The actual mean value we do calculate and use.

While the individual analytical ratios vary for the different indi-
vidual determinations in a series and even the means for the different
series, it is found, as a matter of fact, that they bear a close relation
to the atomic ratio. We call the excess of the analytical ratio over
the atomic ratio, the analytical excess and designate it by the symbol
e. That is: r^R -[- ^- The value of e is also expressed in units
of the fifth decimal.

The Equation of Condition and the Solution Ex-^Eouo.

In the true atomic weights of 1894 (p. 139 to p. 169, esp. p. 158)
the solution of the great problem is already shown to require an
application of the method of the variation of constants.

In the absolute atomic weights of 1901, the change or variation
A of the atomic ratio for an increase of o.i in the atomic weight
is determined for each reaction and applied for several important
objects throughout the entire work. On pages 144-147 of that work
the final solution is really given but implicit only, and lacking the
equal distribution of the analytical excess among the elements
present in the reaction.

The actual equation of condition was established in 1907 through
long and difficult work, both analytical and geometrical. The gen-
eral analytical deduction by means of Taylor's formula was in the
hands of eminent men abroad in the form shown in fac-simile
(reduced to J'^) as printed p. 61 of my " Cinquantenaire," 1910.
The most general construction, which permits the establishment of a
criterion for the absolute atomic weight, is printed on p. 60 of the
same " Cinquantenaire."

Here we will present the final practical solution of the resulting
" insoluble " indeterminate or diophantic equation in the simplest
and most direct manner, suitable for common, current, practical
application.

The true atomic weight, A, is the quantity sought, in the unit for
which carbon-diamond is 12 exactlv.

198 HINRICHS— ATOMIC WEIGHT OF VANADIUM. [April 21,

The absolute atomic zi'eight a is indicated by the laboratory
work; in case of doubt, the criterion just referred to has to be
made use of.

The departure e is expressed in units of the third decimal
(thousandths) of the unit of atomic weights. Its exact determina-
tion is the main object of this paper.

The atomic ratio i? is a function of the absolute atomic weights,
expressed by the quotient P/Q above given.

If now the absolute atomic weight for any one given element in
this ratio be increased by o.i, that ratio will change or vary by an
amount readily calculated from the formula of R as given ; we use
throughout seven place logarithms which give the precise value
sought with the least trouble. This change or variation we denote
by the Greek capital delta A for the particular element of which the
atomic weight was increased by o.i in the atomic ratio. In 190 1 we
made this calculation only for one element in the ratio ; now it has
to be made for every element in the ratio.

In the tables here followmg this matter will become quite readily
understood by simply repeating some of the calculations thus indi-
cated. For the reaction no. 98 this work is quite simple, for only
two elements are present, namely Va and O. In reaction 270, the
work required is about double in amount, because four elements are
in reaction, namely : Va, O, CI and Ag.

The analytical ratio r has to be calculated for each single deter-
mination made; it is considerably simplified if the weighings are
given by the chemist to the hundredth of the milligram, are rounded
off to the tenth of the milligram, which is as far as the weighings
can be trusted ; see, for example, my demonstration of this fact for
the weighings of Richards made at Harvard-Berlin.*

The analytical excess e is now obtained as it is r-R ; it is also
expressed in units of the fifth place.

Now we have in hand all the quantities required for obtaining

the departure e sought, by solving the equation of condition. While

this indeterminate or diophantic equation is, of course, insoluble in

general, we have nevertheless obtained two practical solutions of

the same-"* of which the one properly named ex-cequo is the most

Wlojiitciir Scioitifique, Juin, 1909, especially pp. 384-385-

^Comptcs Rcndus. T. 149, p. 1074, 1909. ^vith a most instructive figure.

191 1.] HINRICHS— ATOMIC WEIGHT OF VANADIUM. 199

serviceable and by far the most readily understood and easiest
applied.

Our general deduction (really as indicated 1894 already: a
method of the variation of the constants) leads to the simple form
of the equation of condition

100 (7 = 2A€,

where the constant 100 presupposes that the analytical excess e and
the variation A are expressed in units of the fifth place while the
departure c is expressed in units of the third place or thousandths
of the unit of atomic weights.

It may not be amiss here to insist on the fact that since in every
chemical reaction there are at least two elements present, the above
equation contains at least two unknown departures e. and is there'
fore really an indeterminate or a diophantic equation.

Our practical solution ex sequo of this equation is as follows :
Let m be the number of elements involved in the chemical reaction,
used, then the number of terms Ac in the above sum 2 is m.

Ascribing to all elements an equal influence on the error or excess
e, the part thereof due to each element will be e'^=e/m.

Hence the actual departure e for each element in the reaction
will be determined by the simple relation

100 e'

If the value of A be above a certain limit, this determination will
be sharp; the corresponding reaction therefore may also be called
sharp.

But if the value of the variation A for any element is small,
the reaction for that element zinll be dull and the determination of
the atomic weight will be impossible with any high degree of pre-
cision, as we have shown in Comptcs Rcndns, T. 148, p. 484, 1909,
in the attempted determination of the atomic weight of Tellurium by
a reaction quite dull for that element.

This one attempt strikingly shows the real condition of the
work of the dominant school to be irrational.

After having briefly explained the manner in which we have
tried to solve the great problem of the deduction of the true atomic

200 HINRICHS— ATOMIC WEIGHT OF VANADIUM. [April 21,

weights from the experimental work done in the laboratories, we
may proceed to the full statement of the facts obtained for the ele-
ment vanadium during the past eighty years and the final results of
our discussion of the same.

We shall present the facts in the most compact form of tables and
finally exhibit them to the eye in the form of accurately drawn
graphics, from which we shall be able to read the final result the
most readily and clearly.

THE ACTUAL DETERMINATION OF THE TRUE ATOMIC WEIGHT

OF VANADIUM.

I. — Absolute Atomic Data.

Fundamental Constants, Calculated from the Absolute Atomic

Weights.

Only seven'"'^ chemical reactions have been used for the determi-
nation of the atomic weight of vanadium, thus far ; they are the
following :

No. 98 : Pentoxide reduced by hydrogen.

No. 269 : Oxychloride to silver.

No. 270: Oxychloride to silver chloride.

No. 311: \^anadate to chloride.

(o) — Oxychloride to pentoxide.

{b) — Sulphate to barium sulphate.

(c) — Sulphate to pentoxide.

The last three preliminary methods of Berzelius have been used
by him, each once only, and by no other chemist, except that Roscoe
made four determinations according to method (a). No. 311 has
but just been introduced by Edgar F. Smith, December, 19 10. All
the chemical reactions used for the determination of the atomic
weight of vanadium, up to that date, were devised and first used
by Berzelius in 1831, eighty years ago. It seems that his work has
some scientific value, after all.

In the following Table I. we have given the most important fun-
damental constants required by our method of reduction. They
have all been calculated from the well-known absolute atomic
weights: Va, 51; T, 16; CI. 351/^; Ag, 108; Na, 23; S, 32; Ba,

'" If we count 269 and 270 as distinct reactions.

igii.]

HINRICHS— ATOMIC WEIGHT OF VANADIUM.

201

137^/^ ; H, 1.008 instead of the exact value 1.00781 determined
atomechanically by us (Rcvuc gen. dc Chiiiiic, 1910. p. 386).

TABLE I.

Fundamental Constants for Vanadium.

269
270
3"

O,

VaOClj

3Ag
VaOCla

NaCl

Va,05
2VaOCl3

VaPs

2B^S07
Va,0.

Atomic Ratio, R.

Fraction.

Decimal.*

0.17 582 I —19
0-53 549 31

32

182
173-5
324.0

'73-5

7— — f 0.40 302

430.5 r ^ -^
58.5 I

122:^ °-47 951

182

347
182

467
182.00

Variation A for

O.

Va sulphate' 398.06

0.52 450

0.38 972
0.45 722

-39
27

43
27

62

31

23

— 118

"3

Ci.

93

42

304

91

40 |- i7(S)
35 !— 23(S)

Metal.

-49 (Ag)

-28(Ag)

43(Na)

-17 (Ba)
-140(H)

II. — General Summary of the Experimental Work Done.

In the common reviews of the experimental work done for
atomic weight determinations, the amount of substance taken in each
experiment is not made the subject of special consideration. This
neglect is due to the erroneous estimation in which the so-called
"probable error" of the mean is held.

This probable error has caused the most serious errors in all
branches of physical science where it has been applied — in the un-
fortunately common way. without proper understanding. We have
treated of this repeatedly, especially in our " absolute atomic
weights, 1901. on the first hundred pages, to which we must refer.

In the language of Berzelius already quoted we might say the
above probable error is the gnat strained at which hides from sight
the camel-like systematic and constant errors which are swallowed.
We have, at last, seen one admission of the fact we have always

^ Between the second and third decimal of the five, we always leave a space
to make the constancy of the first two conspicuous.

'The crystallized sulphate is [VaOJ^S^Os -f 4H=0.

202 HINRICHS— ATO^IIC WEIGHT OF VANADIUM. [April 21,

accentuated, that large constant and systematic errors may exist
though the value found for the probable error of the mean is in-
significant. In Clarke's third edition (1910, pp. 93-98) the probable
error of the mean amounts to only one unit in the fifth decimal of
the analytical ratio while the constant error of that ratio amounts to
120 such units, according to the famous analyses of Stas and Baxter.

To detect the constant and systematic errors we have always
plotted the results of the individual experimental determinations
as ordinates to the weight taken as abscissse. In these diagrams
the scale selected for the atomic weights or the ratios must be very
great while that for the weight taken has to be small. In my diagram
representing in this manner all the atomic weight determinations of
hydrogen made in a century (Rcziic gen. dc Chiiiiie, 1910, p. 380)
the unit of atomic weights is 30 meters (about 100 feet) while a
decagram of water produced is represented by three centimeters
(or a little over one inch).

To permit this scorch for the really iniportant constant and sys-
tematic errors, we give the weight taken (to the decigram) in all our
tables. For a series of determinations, we give the total weight
taken for all the determinations of the series, and the mean weight
taken for each determination — which is obtained from the total by
dividing this latter by the number of determinations made.

Table II. thus shows that 50 determinations have actually been
made for the determination of the atomic weight of vanadium on
4 grams each of the substance taken, not counting the seven pre-
liminary determinations on i gram of matter each.

It is also seen at a glance that by reaction 98 the work of Roscoe
ought to be the most reliable, while for 270 the work of Prandtl
should be the best and that the work done by one chemist for 311
has been carried out under equally as favorable condition in regard
to the weight operated upon.

By means of the reference letter specified in the last column the
corresponding line on the diagrams can be instantly identified. We
may here already remark, that the length of this line, extending to
the right or to the left from the vertical in the middle, marks the
magnitude of the departures for the elements as indicated by the
chemical symbol added.

ign.]

HIXRICHS— ATOMIC WEIGHT OF VANADIUM.

203

Thus the least deviation or departure has resuhed from the use
of the ^Method 311 recently introduced by Edgar F. Smith. The
preHminary work of Berzehus, done eighty years ago, according to
methods a and b as represented by Hnes D and T on the diagram,
showed departures for sulphur and barium extending beyond the
limit of our diagram: 470 to the left (negative) in line D and
776 to the right (positive) in line T; the former is almost half a
unit, the latter three quarters of a unit of atomic weight.

TABLE II.
Summary of the Experimental Determination.

Reaction.

Number of
Determ.

Weight Taken, Grammes.

Chemist.

Mean.

Total.

Diagram.

98

3
I

5
4

1.6
0.6
6.0
2.5

4.7

0.6

30.0

lO.O

Berzelius
Berzelius
Roscoe
Prandtl

B
B*
F
C

269
270

13

9

I

6
2

5
6

4

3-4
2.7

1.6
1.2
2.4
4.7
4.8
8.1

45.3

24.3

1.6

7.4

4.7

23.5

28.8

32.4

Roscoe

Berzelius
Roscoe (A)
Roscoe (Bj
Prandtl, I.

II.

III.

N(M, R)
G

L
P
0

3"

24
5

4-1
6.0

98.4
30.2

Smith-McAdam

Q

Total
or say :

51

50

3-9

4

198.2
200

Preliminary Reactions

(a) Oxychloride

I

1.6

1.6

Berzelius,

1831

A

to Pentoxide

4

I.O

4.0

Roscoe,

1868

E

(b) Va Sulphate

to Ba Sulphate

I

0.8

0.8

Berzelius,

1831

D

(c) Va Sulphate

to Pentoxide

I

0.8

0.8

Berzelius,

1831

T

Mean

7

1.0

7.2

204 HINRICHS— ATOMIC WEIGHT OF VANADIUM. [April 21.

III. — The Analytical Results.

The chemical work, beginning with the determination of the
weight p and ending with the determination of the weight q (or the
inverse) gives directly the atomic ratio r, by a simple division carried
to five decimal places. A simple substraction now will give the
analytical excess e by using the atomic ratio calculated once for all
for the reaction. The results obtained in this way are given in
Table III.

We will here only call attention to the following peculiarly inter-
esting circumstances :

" Analyst B " working under Roscoe makes three determinations
under reaction 269, and takes almost the same weight of the oxy-
chloride for each one of these determinations ; notwithstanding the
fact that he really only repeats one and the same determination three
times, his results range over 501 units in the fifth place — an enor-
mous range under so favorable conditions.

In the language of Berzelius, this enormous range is quite a big
camel which was swallowed without an effort in the laboratory of
Roscoe, who strained laboriously at the tiny gnat of phosphoric acid
which a test of high delicacy, that was not yet known in the days
when Berzelius did his splendid pioneer work on vanadium and
courteously presented to Faraday a sample of the vanadic acid he
had received from his disciple who discovered the element vanadium
and which acid Berzelius had purified himself as far as the science
of his time permitted. These facts I gather from Becker, Smithson.
Misc. Collections, 358, Washington, 1880, p. 132, quoting from
Licbig's Aimalcii, 93, p. 6, 1868.

TABLE III.
The Analytical Ratios Determined.
Reaction 98. — Atomic Ratio, R = 0.17582.
Berzelius, 1831. — Meyer-Seubert, " Atomgew.," 1883, p. 28.

Sums of Weights. r, e.

Determ. Pentoxide. Oxygen.

3 4-6995 0.8120 O.T7 278 —304

I 0.6499 O.I 124 294 — 288

Diagram. Lines B and B".

igii.]

HINRICHS— ATOMIC WEIGHT OF VANADIUM.

205

Roscoe, 1868. — Jour. Chem. Soc, 6, p. 330, 1868.

No. I. 2. 3. 4

Weight Oxide y.~ 6.6 5.2 5.1

r = o.i7 533 507 489 515

e= — 49 — 75 — 93 — 67

Range 44. — Diagram, Line F.

5-

5-4

Mean
6.0

501
- 81

SO9

— 73

Prandtl, 1910. — Jour. Am. Chem. Soc, 191 1, pp. 266-7, from Ztsch. anorg.
Chem., 67, 257.

No. I. 2. 3. 4. Mean.

Weight Oxide 9.1 9.9 8.7 12.3 lo.o

r = o.i7 261 376 395 394 356

f= —321 — 206 — 187 — 188 — 225
Range 133. — Diagram, Line C.

Reaction 269. — Atomic Ratio, /? = 0.53549.
Roscoe, 1868; Analyst K.—Jour. Chem. Soc.. Vol. 6.

No. I. 2. 3.

Oxychlor. 2.4 4.7 4.2

r = o.53 425 528 533

^= — 124 — 21 — 16

Range : 108. — Diagram : Line M.

Roscoe, 1868; Analyst B.

4-

5-

6.

Mean.

4.0

0.9

14

2.9

510

530

532

510

— 39

— 19

— 17

— 39

Mean

No.

7-

8.

9-

Mean.

of All 9.

Oxychlor.

2.9

2.1

1-4

2.1

2.7

'' = 0.53

980

755

479

738

586

e =

431

206

— 70

189

37

Range: 501. — Diagram: Line R. Range: 555.

Re.'^ction 270. — Atomic Ratio, R = 0.40302.

Berzelius, 1831. — i determ. : 1.6385 oxychlor. gave 4.0515 Ag, hence r
0.40442 and e 140. Meyer-Seubert. " Atomgew.," 1882, pp. 90-91.
Diagram : Line G.

Roscoe, 1868; Analy

St A:

No. I.

3.

0

4-

5-

6. Mean.

O.xychlor. 1.9

0.7

0.8

1-4

I.O

1.6 1.2

r = 0.40 323

531

537

337

399

174 383

e^ 21

229

235

35

97

— 128 81

Range : 363. — Diagram : Line H.

Analyst B :

No.

7-

8.

Mean.

Mean of A and B.

Oxychlor.

2.2

2.5

2.4

1-5

r = 0.40

391

333

362

378

e^=

8.9

31

60

76

Range : 58. — Diagram Line

K.

Diagram : I.

206 HINRICHS— ATOMIC WEIGHT OF VANADIUM. [April 21,

Prandtl and Blcycr.^ Series I., 1909.

No. I. 2.

Oxychlor. 5.5 5.9

r = 0.40 393 346

e=^ 91 44

Range: 71. — Diagram: Line L.

"Clarke, " Recalc," 1910. p. 307 for I. and II.; Jouni. Am. Chem. Soc,
191 1, p. 266, for III.

3-

4

s-

Mean.

3-^

5-3

3.6

47

365

3^^

367

359

63

20

65

57

Si

ERIES II.,

1909.

No. I.

2.

3-

4-

5-

6.

Mean.

Oxychlor. 4.9

37

5-0

6.5

4-3

4-1

4.8

r = o.40 331

286

318

315

308

3^5

314

f = 29

— 16

16

13

6

23

12

Range : 45.— Diag

ram : Line

P.

Series III.,

, I9IO.

No.

I.

2.

3-

4-

Mean.

Oxychlor.

7.8

8.4

10.7

5-5

8.1

1- = 0.40

301

311

3^1

333

317

c ^^^

— I

9

19

31

14

Range : 3,2. — Diag

ram : Line

0.

Reaction No. 311.— Atomic Ratio. 7? = 0.47951.
Edgar F. Sinitli and McAdam, Jour. Am. Chciii. Soc, 1910, p. 1614.
No. I. 2.

Vanadate 4.9 5.6

/• = o.47 931 927

f = — 20 — 24

Range : 20. — Diagram : Line Q.

Strictly this series consists of 3 determinations only, two of

which have been made twice, as follows :

3-

4-4

4-

5-8

5-

9-5

Mean.
6.04

941

937

921

931

10

— 14

— 30

— 20

No.

Vanadate

I-3-
4.6

2.4.

57

5-

9-5

Mean

6.0

r = 0.47

936

932

921

931

e =

— IS

— 19

— 30

— 20

Range: 15.

This shows how even within narrow limits of weights taken
(here from 41^2 to 9% grammes) the systematic error becomes evi-
dent as a function of the weight taken. Within the actual range,
the analytical excess approaches zero with diminishing amount
operated upon.

Preliminary Work.

.•Analytical
Reac- Ratio. Excess.

Line. tion. r. e.

A. a I det. 1.6385 oxychl. gave 0.874 oxide 0.53342 892 Berzelius.

E. 4 det. 4.0418 2.1258 0.52608 158 Roscoe.

D. b I det. 0.351 pentoxide 0.913 Ba sulphate 0.38445 —527 Berzelius.

T. c I det. 0.351 pentoxide from 0.775 Va sulphate 0.45290 + 432 Berzelius.

I9II.]

HINRICHS— ATOMIC WEIGHT OF VANADIUM.

207

IV. The Analytical Excess.

The analytical excess c is only comparable in work carried out
according to the same chemical reaction by dilTerent chemists. This
condition has determined the form of Table YV., in which the capital
letter marks the line on our final diagram representing the work,
while the numbers below the letter represent: the first, the number
of determinations made, the second giving the analytical excess
obtained. This excess will naturally be found the greatest for all
preliminary (or pioneer) work such as that done by Berzelius in his
single trials of reactions (a), (&), (c).

This table makes it very apparent that each succeeding chemist
benefited by the work and experience of his predecessor. This
show^s best under reaction 270 where Berzelius (i determination)
gives the excess 140, Roscoe (8 determinations) only 76 and Prandtl
(15 determinations) brings it down to an average of 28 only.

For Reaction 98 this relation holds good for the work of Berze-
lius and Roscoe only, while that of Prandtl, done as recently as
1909, reaches almost the excess of Berzelius single first trial of
eighty years ago, although Prandtl used the mean weight of 2.5
grams while Berzelius had onl\- half a gram for his work.

TABLE IV.
The Resulting Analytical Excess.

Reaction.

98

26q

70

3"

a

^

c

Chemist :

Berzelius,

B

G

A

I

D

1831

3
B'

I

—304

I

140

I 892 1 I —527

I 432

—288

Roscoe,

F

R

H

E

1868

5

— 73

3

N

1 89

6

I

81

4 158

I

9

M

I

37
—39

8
K

2

76
60

Prandtl,

C

L

1909

4

—255

5
0

4
P
6

57
14
12

Smith-McAdam,

—

Q

1910

5 — 20

208 HINRICHS— ATO^IIC WEIGHT OF VANADIUM. [April 21,

\\ The Final Departures.

In this table ( I\'. ) we have finally given all the departures for
all the elements taking part in the different reactions used for the
determination of the atomic weight of vanadium during the last
eighty years — from Berzelius in Stockholm to Edgar F. Smith in
Philadelphia. We have fully explained the manner of calculating
these departures; every reader can verify any of these values for
himself by the methods stated. Since the element most concerned
is vanadium, we have arranged the record of departures in the order
of the magnitude of the departures of vanadium, for which the ex-
treme values are 1062 and minus 307, giving a total range of 1369,
say one and one third units of atomic weight ; that is, from Va 52.06
to 50.69.

If we omit the pioneer and preliminary work done by Berzelius
in trying reactions (a) and (b), the extreme departures will be 800
and — 31. a total range of 831 only. The atomic weights will run
from 51.80 to 50.69, which is a remarkably fine showing for so long
a series of very difficult w^ork on the rare element.

To realize the generally excellent work of the early days of Ber-
zelius and of Roscoe — when the element was decidedly rare and diffi-
cult to purify — we need only compare the limits of the determina-
tions by Prandtl of today with the range of the entire series (ex-
cluding only, as we have done already, the reactions (a) and (b)) ;
these extremes of Prandtl are 594 with reaction 98 and 13 in Series
II. with reaction 270; a total range of 581 thousandths. The corre-
sponding atomic weights of vanadium are 51.59 and 51.01 differing
58 hundredths.

We are greatly tempted to point out a number of interesting fea-
tures on this table, but fear that the paper will assume undue length
and trust the reader will help himself.

We only remind the reader that the letter in the first column of
this table permits the ready identification of the experimental result
expressed in numbers in this table with the graphical representation
on our two diagrams.

191 1.] HINRICHS— ATOMIC WEIGHT OF VANADIUM.

209

TABLE V.
The Departure. Determined from Eighty Years of Work.

Line in

Reac-

No.

Analyt.

Departure, e, in

Thousandths.

True
Atomic Weight

Dia-

Chemist.

tion.

of De-
term.

Excess,
e.

gram.

Va

0

CI

Metal.

Va.

0.

A

Berzelius

a

I

892

1062

263

—326

52.06

16.26

B

"

98

3

—304

800

—245

51.80

15-75

B*

"

98

I

—288

784

—241

.78

.76

C

Prandtl

98

4

—225

594

-183

•59

.82

D

Berzelius

c

I

432

400

— 310

_47o9

- 77"

.40

.69

E

Roscoe

a

4

158

195

47

-58

.20

16.47

F

"

98

5

— 73

192

— 59

.19 15.41

Ag:

G

Berzelius

270

I

140

153

153

83

-125

• 15

16.15

M

Roscoe (B)

269

3

189

150

150

50

— 95

• 15

-15

H

" (A)

270

6

81

87

87

47

— 71

.09

.09

I

" (A, B)

270

8

76

83

83

45

— 68

.08

.08

K

" (B)

270

2

60

65

65

36

— 54

.07

.07

L

Prandtl, I

270

5

57

62

62

34

- 51

.06

.06

N

Roscoe (M, R)

269

9

37

30

30

10

— 19

•03

•03

0

Prandtl, III

270

4

14

15

15

7

— 12

.01

.01

P

II

270

6

12

13

13

7

— II

Na:

.01

.01

Q

Smith-McAdams

3"

5

— 20

13

4

— 2

— 12

Ag:

20

51.01

16.00

R

Roscoe (A)

269

6

— 39

— 31

— 31

— 10

50-97

15-97

T

Berzelius

h

I

—527

—307

—330

7769' 77611

.69

15.67

H.

Ba.

VI. Our Graphics.

The values of all departures given in Table V. are represented to
the eye in our two graphics.

Fig. I gives all the larger departures and as many of the smaller
ones as space would permit. The scale used is 200 thousandths of
the unit of atomic weights to the inch ; or, what amounts to the same,
the unit of the atomic weights is represented by five inches in length.

Fig. 2 gives all the departures of the central region on a scale
which is five times the one used in the construction of the first figure.
Hence in Fig. 2 the unit is represented by a line of twenty-five inches ;
or, in other words, it shows forty thousandths to the inch.

The vertical of the ordinate represents the departures of vana-
dium, while the departures of the elements combined with vanadium
are set off on the horizontal as abscissse.

The results for a complete analysis of any given compound are
therefore set off on the horizontal line drawn through the point on
the vertical determined by the departure for vanadium.

a

Dcpa.rtu.T4 looo— •- Vol =.52 .

-f-JO O

7

"Pf rr/o..

']oo - The Laboro-tory Hor^

of Etglxbu xjcars
^stctbltshes

4

■^ Vet —5/ eAcct^kit/,

0

y •

0

1/ . . . Pery.toK : Vo-ScO^K^tB-

• ioo

I

CL

H: (i) ®-®-(i)

Q:

.^

-^ 3//.

Vct = 5/.

Sca.t£ oj^ —TOO ^ o ^^„

•* ^ y • Vci.-rL.ct.cLxA^/*n, .

o^i\ <

Vc«

La.bora.toru V^rK.
BczcIlU-S, la 31 ;

®

Roscoe,

l66a?

S^iiiVvo*.! V<» : Hc«

"O I:

1. 5 , ?ranoLa-B«u£y;N0q:

^/Z'^- •

I.KSialt(^-n*Adani,/<)lO.

1 1 Lj . . 1 i

~iO<i -loo

Fig. I. Departures. Scale 200 thousandths to the inch.

•.

§ ■ S'lJ^-p-WBSr.oT^:) lA.! ^

-^ ^^n^AT,c/T,(y- p

X

1 1

~5

\

0 ^

0

^ i S ^

^r-

c^

'^ X i o •=^

\ ' ^

•^ ^ ^j ^,

^<

®

0

"^

\o =

0^

3

0

(s)

a

\

®— 0

6

•)-^^

-— *

^f

^\

\

1-^

o

M

J ^> -

(3

K

*^

'O^

. cr.

o o

1?

r —

rs

^

■*■ '-n

-

-.

1

(D

^

'--)

1^ s^

■«§>-

— «-

^Sli

(^

«) ®-«

►- +

-® — ^-i^

I ®

J

jlI

;ix

*

i^

-- /•fto"

^

0

y^

. ^

y^ y

5i

,

r 2 o^ ■

CO

(V

•

(7

■s

rr. 3i « ^

00 «; 5^ ^ =

ssr>°

^'°

y

-. o « 1 ^
3 - ■'. ^ *

,/

c- 5 ? "■ -^

^- o 't; i: ^
=»- ^ P:j vP

rv. "^ 3" ■-- ^

CO .. ,^ «-. ,_,

- '^ fs £ r^

4

5

fQ fc^ ci: M J :

■' "> '^ ~. .. 2

i

0

y

^' •• \^'^ 1

• ® • >v>-

0'

•

X

i

.2 ^-> <r -?^ « 0

ju O ro ft^ > -Q

i " § o d -^

1 y-

y
1 5

. 1 0-

0

1

j5: CO O C5 _; ^
^ r,! rs fr> >

212 HINRICHS— ATOMIC WEIGHT OF VANADIUM. [April 21,

The chemist whose work is represented is indicated by the special
mark used to designate the point, as shown in the explanation of
signs on the diagram.

The small figure near the vanadium sign on the vertical indicates
the number of determinations made represented in that line.

The line itself is marked by a letter, used in the tables for the
purpose of ready identification.

For each reaction, the geometrical place (or locus) is a straight
line passing through the center or the origin ; the angle under which
it cuts the axes is determined by the ratio of the variation of the
element concerned and that of vanadium. These lines can therefore
be drawn before any laboratory work is done, depending entirely on
the chemical formulas of the compounds taken and obtained in the
reaction used.

For further particulars, some of which are very interesting as
well as useful, we may refer to page 60 of our " Cinquantenaire,"
where also a remarkable criterion is given, permitting to detect any
error in the assumed absolute atomic weight. The example there
taken is copper.

Our two figures here inserted bring into clearest possible view^ the
fundamental fact that all these departures are co-related ; that the
experimental error is not thrown on the vanadium for which the
atomic weight is sought, but is distributed ex-aec|uo to all elements
partaking in the reaction, as we have shown in formulae, but which
is here presented to the eye directly.

We do not recognize or find the slightest pretext for the assump-
tion that any one element is immaculate and cannot be conceived to
partake in any error of whatever cause or origin ; but we have found
that all elements in a chemical reaction are afl:'ected by the same
cause of error according to the ties that bind them and which we
have read in the chemical formula and in the mathematical relations
first studied by Lagrange under the name of the \'ariation of arbi-
trary constants. ^-

We know that it is absurd to suppose that oxygen is always found
to be 16, absolutely unaffected by any error, physical or chemical, in
practice ; that next some other atomic weight of some other element

""True Atomic Weights," 1894, p. 158.

191 1.] HINRICHS— ATOMIC WEIGHT OF VANADIUM. 213

can be determined and that this value also will remain unaffected in
all reactions ; and so forth. That errors rapidly accumulate in such
an irrational process, we have shown as far back as 1893, almost
twenty years ago. That paper was presented by Berthelot to the
Academy of Sciences of Paris and published in its Co/n/'/^^i?(';;rf»^.^^

After having completed a thorough examination of all the atomic
weight determinations made, we have, by a sort of crucial test, dem-
onstrated that the present value Ag 107.88, implying a departure of
120 thousandths, is impossible; that O 16 requires Ag 108 exactly,
according to all determinations made during an entire century in all
the laboratories of the world."

It is this same principle that is demonstrated by the diagrams
here printed and this demonstration is made visible to the eye : It is
not vanadium alone that causes the error affecting the laboratory
work, but all elements in the reaction contribute to the error recog-
nized in the final result of the analytical work.

Instead of the common notion that the work of the different
chemists conflicts in the different values they have presented as the
results of their determination of the atomic weight of vanadium our
figures here inserted show to the eye that all determinations made
agree in the common result of J'a fji exactly. While no experimental
work of any kind,' done by man, with instruments and by chemical
reactions, all of which are but approximations to a mathematical
perfection, can be expected to give perfectly exact results, we have
proved that the final error cannot be ascribed to vanadium alone, as
continues to be done by the dominant school, but that on the contrary,
all the elements present in a reaction contribute, each one its share,
to the Excess or deficiency resulting. It was therefore necessary to
find the laws regulating this participation of the different elements
in the errors of the reactions and of the entire experimental work.
Having discovered these laws, we have applied them here, to the
atomic weight determinations made for vanadium and present in the
two graphics (Figs, i and 2 ) the final results thus obtained.

These figures show plainly that all the departures from the abso-

^=T. 116, p. 695.

''* See paper read December 2, 1910, before the American Philosophical
Society; Proceedings, 1910, pp. 359-363.

214 HINRICHS— ATOMIC WEIGHT OF VANADIUM. [April 21,

lute values are converging to zero along each of the lines of work
pursued in the eighty years by the different chemists ; there is but one
insignificant exception, which we shall consider, when we take up
the recent work of Prandtl.

Our Figs. I and 2 proclaim that the atomic weight of vanadium
is exactly 51 in all these determinations, just as sure as oxygen has
the atomic weight 16 exactly and silver 108 exactly, chlorine 35^
exactly, sodium 23 exactly ; in fact, all the elements have as atomic
weights exactly the absolute values given in our publications of the
last twenty years.

Even the very first determinations made by Berzelius, with only
a fraction of a gramme of material at service, and only in one single
determination, by the reactions designated (a), (b) and (c), do
confirm the value Va 51 ; for the deviation noted for \'a affects all
the other elements present as well, and therefore it would be absurd
to suppose that the atomic weight of vanadium could be obtained
from a reaction which fails to give an exact determination for the
other elements present. Thus reaction (c) represented by line D in
Fig. I, gives by the single determination made by Berzelius on 8
decigrams of the rather complex hydrated vanadium sulphate, a
departure of 400 thousandths from 51 for the atomic w^eight of
vanadium ; but the same determination gave the atomic weight of
oxvgen 310 thousandths low as marked on the figure; it also gave
the atomic weight of sulphur 470 thousandths low as indicated near
the edge of the diagram and by the arrowpoint : for the real circular
mark falls far beyond the limit of the diagram.

Is it so hard to understand that a reaction that fails to give pre-
cise determinations for all the elements it involves cannot necessarily
be expected to furnish a value of precision for vanadium? Is it not
about time for each individual chemist to begin to consider these
simple facts for himself, as was the practice in former days?

It would be interesting to trace the gradual approach to the center
where all departures are zero, as exemplified in the actual work of
the successive chemists. This will be found to hold good for all,
with the single exception alread\' mentioned. We will only point
to a few special instances, expecting the reader to go over the entire
ground bv himself.

191 1.] HINRICHS— ATO^IIC WEIGHT OF VANADIUM. 215

The preliminary analysis, represented in the line A at the top
of Fig. I, gave not only the greatest departure for \'a, but also for
O, in the only determination made by Berzelius. When Roscoe,
forty years after, made a series of four determinations the result
entered at E in our figure (both i and 2) he cut the departure from
1062 to 195 for A'a and from 263 to 47 for oxygen. If this determi-
nation were repeated with the benefit of all the progress made in
laboratory work, the resulting mark would undoubtedly find its
place much nearer the zero departure on the line (mainly dotted)
on our figure ( i ) .

Let us also look at the results obtained by the use of reaction
270, best seen on Fig. 2, lines G. H, I, K, L, O, P. Of these lines,
G is the most distant, representing the largest departures : it marks
the one determination made by the old master in 183 1. Then we
meet, in going toward the center of perfection or zero departure, the
lines H, I and K bearing the mark of Roscoe and only about half as
far from the zero as the line G of 1831. The total number of deter-
minations made by Roscoe in 1868 was 8, represented by line I; 6
of these eight were "done by Analyst A" and are represented by
line H ; the other two were " done by Analyst B " and are represented
by line K. Finally we have three series ( I., II. and III., repre-
sented by lines L, P and O, respectively) made by Prandtl quite
recently ; of these, the last two series come quite close to the center,
the departure for Va being 14 only for the mean of the two series
(see Table V.). Since on our diagram the departures for O, CI
and Ag are set off as abscissae to that of Va taken as ordinate, the
gradual diminution of all the departures is strikingly shozvn iu the
lines for these elements conz'erging to the point of zero departure.
At the same time we here have the positive evidence that Prandtl
has produced two very concordant series (his II. and III.) with a
very small departure (mean 14 for A'a and O) and one series (his
first, I.) represented by line L for which the departure is 62, that
is more than four times as large.

Now we may consider the results obtained by the reduction test,
reaction No. 98, represented on our Fig. i by the lines B, C and F.
Here we meet that one exception before referred to ; for the greatest
departure (lineB) of Berzelius is but slightly diminished by Prandtl's

216 HINRICHS— ATOMIC WEIGHT OF VANADIUM. [April 21,

quite recent work (line C) and far surpassed by the small departures
of the much older work of Roscoe (line F). It is to be hoped that
Prandtl will also make one or two additional series under reaction
98, as he has done under 270 ; we dare say that, with due care, he
may repeat the experience he has reported for reaction 270 and
greatly reduce the departure, at least to that of Roscoe in 1868.

It will hardl}" be necessary to state that the numerical data we
have quoted in the discussion of our Figs, i and 2 are taken from
tables II. and V. especially.

CONCLUSIOX.

We think that the reader will have no trouble now in completing
his study of the facts placed before him in our tables and in our
figures which both comprise much more than their size would seem
to indicate.

We therefore think that the reader will fully understand the utter
fallacy of throwing all the errors of all kinds on the one element,
the atomic weight of which the modern chemist tries to determine
" in the chemical laboratory and by experiment exclusively."

The reader will, we believe, now fully comprehend the situa-
tion— both of the chemist and of his intended victim, the element.
The victim — if it were conscious — would shiver in anticipation of
being made responsible for every error and mishap that may befall
any of the elements present in the reactions, the apparatus used and
even the chemist at work ; for all these errors and shortcomings the
modern chemical school dc facto charges up to the element the
atomic weight of which it undertakes to determine. The only new
step — other than what the general progress of practical laboratory
work may favor him with — will be the straining out a few more
innocent gnats without in the least disturbing the ever attendant
herd of the old camels.

It sometimes does seem strange that in twenty years this Berze-
lian picture from Saint ^latthew (XXIII. , 24) has remained so
true to Nature. It is not the fault of the individual chemists, ex-
cept in so far as they have surrendered a fundamental part of- their
rightful domain to the International Atomic Weight Committee.

THE ORIGIN AND SIGNIFICANCE OF THE PRLMITIVE
NERVOUS SYSTEM.

By G. H. PARKER.
{Read April 21, 1911.)

Linnaeus defined a plant as an organized, living, but non-sentient
body and an animal as an organized, living, and sentient body.
Although no modern biologist would attempt to support the conten-
tion that animals are sentient and plants are not, the distinction
drawn by Linnaeus is not without a certain foundation in truth, for
sentience in its full development and as Linnaeus probably under-
stood it, is the exclusive and supreme possession of the higher ani-
mals. That these animals possess intelligence as contrasted with
all other natural bodies is a statement to which few naturalists will
offer any serious objection. The seat of this intelligence is the ner-
vous system and, though the integrity of the other systems of organs
is essential in most cases to the well-being of the animal body, the
fact that the totality of activities that makes up the mental life of
human beings as well as that of other animals, is absolutely depen-
dent upon the nervous system, is evidence sufficient of the paramount
importance of these organs. It is, therefore, not without interest
to inquire into the origin of this system of organs and to trace the
early steps by which it passed from a position of initial obscurity to
one of the highest significance.

The nervous system of the higher animals, though enormously
complex in its organization, is composed of relatively simple ele-
ments, the neurones, arranged upon a comparatively uniform plan.
This plan is well exemplified in the spinal cord of the vertebrates.
In this organ the sensory neurones, whose cell-bodies lie in the
dorsal ganglia, extend from the integument through the dorsal roots
to the gray matter of the cord. Motor neurones, whose cell-bodies
are situated within the gray matter of the cord, reach from this
region to the muscle-fibers which they control. These two classes

217

218 PARKER— ORIGIN AND SIGNIFICANCE OF [April 21,

of neurones would seem to be sufficient for all ordinary reflex oper-
ations, but the cord contains within its limits many other neurones
which serve to connect one part of its structure with another.
These neurones, therefore, have been called association neurones, a
term which has unfortunately proved to be somewhat misleading
because of its use in psychology for quite a different range of
phenomena. The so-called association neurones are interpolated
between the sensory and motor elements just described and must
thereby lengthen and extend the courses of the reflex impulses.
Such neurones make up a large part of the substance of the cord and
doubtless increase enormously its internal connections. In the brain
they not only add to the nervous interrelations, but they afford in
the region of the cerebral cortex the material basis for all intellec-
tual operations.

The plan of neuronic arrangement as exemplified in the verte-
brates also obtains in animals as lowly organized as the earthworm.
In this form the sensory neurones, whose cell-bodies are situated in
the integument instead of being gathered into special ganglia, ex-
tend, as in the vertebrates, from the skin to the central nervous
organs, the brain or the ventral ganglionic chain. The motor neu-
rones are essentially duplicates of those in the vertebrates in that
their cell-bodies lie within the central organs whence their fibers
extend to the appropriate musculature. Association neurones are
also abundantly present in the earthworm though their function here,
in contrast with that in the higher vertebrates, is pure nervous in-
tercommunication, for it is very unlikely that the earthworm pos-
sesses what in any strict sense of the word can be called intelli-
gence. Thus from a morphological standpoint, the nervous systems
of the higher animals, even including such forms as the earth-
worm, have much in common, their three sets of interrelated neu-
rones, sensory, motor, and association, being arranged upon an es-
sentially uniform plan.

Considered from a physiological standpoint, the nervous system
with its appended parts as just sketched falls in the higher animals
into three well marked categories. On the exterior of these animals,
are to be foimd sense organs or receptors such as the free-nerve
terminations of the sensorv neurones in the vertebrates or the sen-

191 1.] THE PRmiTIVE NERVOUS SYSTEM. 219

sory cells in the integument of the earthworm. These organs have
for their function the reception of the external stimuli and the pro-
duction of the sensory impulses. The receptors are connected by
nerve-fibers with the central nervous organ or adjustor composed of
the central ends of the sensory and the motor neurones and of the
association neurones. Here the impulses arriving from the re-
ceptors are directed toward the appropriate groups of muscles by
which the animal may respond to the stimulus and, if the animal is
highly organized, impressions are made upon the adjustor which, as
memories, may become more or less permanent parts of the animal's
nervous equipment. Finally the adjustors are connected by nerve-
fibers with the third set of elements, the effectors, which as muscles,
electric organs, glands, etc., enable the animal to react on the en-
vironment. Thus three physiological categories are to be distin-
guished which in the order of their sequence in action are sense
organs or receptors, central nervous organs or adjustors, and muscle,
etc., or effectors.

It is to be noted in passing, that the physiological scheme just
outlined includes a wider range of parts than is generally admitted
under the head of the nervous system. The additional parts are the
effectors, which, as will be shown later, form as truly a part of the
whole system as do the sense organs or the central nervous organs.
Since the term nervous system does not ordinarily include the effec-
tors, it is perhaps best to designate the whole chain of related parts,
receptors, adjustors, and effectors, as the neuromuscular mechanism
and in dealing with the origin of the nervous system, it will be found
important to keep this relation in mind, for in such an inquiry, the
real question that must be confronted is the origin of the neuromus-
cular mechanism rather than that of the nervous system alone.

The type of neuromuscular mechanism described in the preced-
ing paragraphs in which a group of receptors is connected with a
well centralised adjustor which in turn controls a complex system of
effectors, is found only in the more dift'erentiated metazoans. Cer-
tainly in the simple metazoans, like the jellyfishes, corals, sea-ane-
mones, etc., only the slightest evidence of this type of nervous orga-
nization can be discovered. Nevertheless these animals possess a
neuromuscular mechanism but on so simple a plan that investigators

220 PARKER— ORIGIN AND SIGNIFICANCE OF [April 21,

have long been inclined to regard it as representing the first step
in the dififerentiation of the neuromuscular organs. This plan of
structure is well represented in the sea-anemones. Each of the two
chief layers of cells that make up the living substance of the sea-
anemone's body consists of three sublayers : a superficial or epithelial
layer, a middle or nervous layer, and a deep or muscular layer. The
epithelial layer contains, besides many other kinds of cells, large
numbers of sensory cells which terminate peripherally in bristle-
like receptive ends and centrally in fine nervous branches. These
fine branches constitute collectively the middle or nervous layer in
which occasionally large branching cells, the so-called ganglionic
cells, occur. Immediately under the nervous layer is the deep layer
of elongated muscle-cells. The condition thus briefly described is
present over the whole of the sea-anemone's body and though the
nervous layer is somewhat emphasized in the neighborhood of the
mouth, it cannot be said to be really centralised in any part. Hence
this type of nervous system has been designated as diffuse in con-
trast with the centralised type found in the higher metazoans.

Not only is the structure of the nervous system of the sea-anem-
one appropriately described as diffuse, but in its action this system
shows those peculiarities that would be expected from the possession
of so diffuse an organization. Since each part of the animal con-
tains its own nerve and muscle, it is not surprising that after isola-
tion many of these parts will respond to stimuli much as they did
when they were a constituent of the whole organism. Tentacles, for
instance, when freshly cut from the body of a sea-anemone will re-
spond to pieces of food by encircling them, etc., in much the same
way as when these organs were parts of a normal animal. ]^Iuch
evidence of this kind has shown conclusively that the nervous sys-
tem of coelenterates is no more centralized physiologically than it is
anatomically, but is in all respects essentially diffuse.

What is really present in the neuromuscular portion of the sea-
anemone's body is a large number of peripheral sensory cells whose
deep branching ends connect more or less directly with the muscles,
i. e., without the intervention of a true central organ. This neu-
romuscular system, if described in the terms already used, could be
said to be composed of receptors and eftcctors without an adjuster

191 !•] THE PRIMITIVE NERVOUS SYSTEM. 221

or at least with this member present in only a most primitive state.
In my opinion this is the condition in most coelenterates. Judging
from the more recent work on the nervous organs of these animals,
centralization can scarcely be said to be present at all in hydra ; it is
but little more pronounced in the sea-anemone ; and, though most
marked in the jellyfishes, it does not rise even here to a grade that
entitles it to comparison with what is seen in such forms as the
earthworm. The coelenterates. then, are animals possessing recep-
tors and effectors but without developed adjustors. Hence the
adjuster or central organ is in all probability an acquisition that
represents a later stage in the development of the neuromuscular
mechanism than that seen in the coelenterate.

If the coelenterates represent a stage in the evolution of the
neuromuscular mechanism in which sensory cells and muscles are
the only important parts present, it is natural to ask if there is not a
still more primitive state from which the C(xlenterate condition has
arisen. On this question several hypotheses have already been ad-
vanced. Claus and, subsequently, Chun maintained that originally
the ner^•ous system and the muscles were differentiated indepen-
dently and that they became associated only secondarily. This view
has deservedly received very little attention, for not only is it difficult
to conceive that an animal would develop receptive ability without
at the same time acquiring the power to react, but not a single exam-
ple among the lower animals is known in which developed nerve and
muscle are present and independent of each other.

Much more worthy of consideration than the hypothesis of the
independent origin of nerve and muscle is Kleinenberg's theory of
the neuromuscular cell. In 1872 Kleinenberg announced the dis-
covery in the fresh-water hydra of what he designated as neuro-
muscular cells. The peripheral ends of these cells were situated on
the exposed surface of the epithelium, of which they were a part
and were believed to act as nervous receptors ; the deep ends were
drawn out into muscular processes and served as eft'ectors to which
transmission was supposed to be accomplished through the bodies
of the cells. Each such cell was regarded as a complete and inde-
pendent neuromuscular mechanism, and the movements of an animal
provided with these cells was believed to depend upon the simul-

222

PARKER— ORIGIN AND SIGNIFICANCE OF

[April 21,

taneoiis stinnilation of many such elements. It was Kleinenberg's
opinion that these neuromuscular cells (Fig. i, B) divided (C) and
thus gave rise to the nerve-cells and muscle-cells (D) of the higher
animals. In fact he declared that the nervous and muscular systems
of these animals were thus to be traced back to the single type of
cell, the neuromuscular cell, which morphologically and physiolog-

FiG. I. Diagram to illustrate Kleinenberg's theory of the neuromusculai"
cell. A, epithelial stage; B, neuromuscular cell; C, neuromuscular cell partially
divided; D, nerve-cell and muscle-cell of ccelenterate stage.

ically represented the beginnings of both. But Kleinenberg's neuro-
muscular cells were subsequently shown by the Hertwigs to be merely
epitheliomuscular cells and no intermediate stage between them and
the differentiated neuromuscular mechanism of higher forms was
ever discovered. Hence this hypothesis, too. has been largely aban-
doned.

Some years later, in 1878, the Hertwigs published an account of
the neuromuscular mechanism in coelentcrates, an account which even
at the present time is accepted as authoritative by most students of
the subject. In this account they described the sensory cells, the
ganglionic cells, and the muscular cells of the ccelenterates, and
maintained that these elements arose not by the division of single
cells, as implied in Kleinenberg's hypothesis, but that each element
was differentiated from a separate epithelial cell (Fig. 2) and yet
in such a way that during differentiation all these elements were
physiologically interdependent. This h}pothesis of the simultaneous
differentiation of nerve and muscle is the current opinion among
biologists today.

igii.]

THE PRBIITIVE NERVOUS SYSTEM.

223

As opposed to Hertwigs' hypothesis of the origin of nerve and
muscle, I wish to present certain facts obtained from a study of
sponges. As is well known, sponges are extremely primitive meta-
zoans, more primitive even than the ccelenterates. All attempts to
demonstrate in them sensory or other nervous structures have yielded
negative results, so that the majority of investigators of this group
have come to regard sponges as devoid of true nervous structures.
Not only are sponges without parts that can be reasonably called
nervous, but so far as I have been able to ascertain by an extended
study of a species of Stylotella, they show none of those qualities of
transmission and relatively quick reaction which characterize even

KnacniL

Fig. 2. Diagram to illustrate Hertwigs' theory of the origin of nerve
and muscle. A, epithelial stage: B. partially differentiated muscle-, nerve-
and ganglion-cell; C, muscle-, nerve- and ganglion-cell of ccelenterate stage.

such animals as have only primitive nervous systems. In fact in
this respect sponges resemble plants rather than animals. But not-
withstanding the fact that sponges show no evidence either anatom-
ical or physiological of possessing nervous organs, they are not
without powers of response. Stylotella, for instance, can open and
close its oscula and its lateral pores, and can even contract its flesh
more or less. These movements, to be sure, are carried out ver\'
slowly, but they follow certain stimuli with such regularity that they
must be regarded as true responses. Thus the oscula of this sponge
close regularly when the water about these openings becomes quiet
and reopen after the water has been again set in motion. These
movements of the sponge are carried out by contractile tissue which
has the appearance of smooth muscle-fiber and which, like smooth
muscle, responds with great slowness. The slowness of the response
is so marked even in comparison with what is met with among the

224

PARKER— ORIGIN AND SIGNIFICANCE OF [April 21,

more sluggish coelenterates, as to suggest that the muscles in question
act not through the intervention of nerves, but under direct stimula-
tion, and since sponges have yielded no evidence anatomical or
physiological of possessing nervous elements of any kind, I have
concluded that their muscles normally act under direct stimulation.
In other words, sponges are metazoans with effectors but without
receptors ; and in so far as their neuromuscular mechanism is con-
cerned, they are metazoans one degree simpler than the majority of
coelenterates.

If this conclusion concerning the neuromuscular mechanism in
sponges is correct, it follows that, of the three elements concerned,
the effector or muscle is the most primitive and has developed as an
organ quite independent of nerve, as seen in the sponges (Fig. 3,

T

nnmnim

A

B D

Fig. 3. Diagram to illustrate the early stages in the differentiation of
the neuromuscular mechanism. A, epithelial stage ; B, differentiated muscle-
cell at stage of sponge ; C, partially differentiated nerve-cell in proximity to
fully differentiated muscle-cell; D, nerve- and muscle-cell of coelenterate stage.

A, B). Next in sequence would appear the receptor or sense organ
which, derived from the cells in the neighborhood of a developed
effector (C), would serve as a more efficient means {D) of calling
this organ into action than direct stimulation. This stage is repre-
sented by many coelenterates ; and their quick responses, as compared
with those of sponges, are dependent, I believe, upon this advance
in organization. Finally, in forms somewhat more advanced than
the coelenterates, central nervous organs or adjustors would begin
to differentiate in the region between the receptors and effectors ;
and these would develop in the higher animals, lirst, as organs of
transmission wherebv the whole musculature of a given form could

191 1.] THE PRmiTIVE NERVOUS SYSTEM. 225

be brought into coordinated action from a single point on its sur-
face and, secondly, as the storehouse for the nervous experience of
the individual and the seat of those remarkable activities that we
recognize in the conscious states of the higher animals. Thus nerve
and muscle did not develop independently, as claimed by Claus and
Chun, or simultaneously, as maintained by Kleinenberg and the Hert-
wigs, but muscle appeared first as independent effectors and nerve
developed secondarily in conjunction with such muscles, first as a
means of quickly setting them in action and, secondly, as a seat of
intelligence.

When we survey the whole range of metazoan development, we
cannot but be struck with the remarkable history of the neuro-
muscular mechanism. The earliest metazoans were doubtless little
more than colonies of protozoan cells concerned with the common
functions of feeding and reproduction and conforming more or less
to Haeckel's hypothetical gastrsea. To these early functions of this
primitive metazoan were added colonial reactions in that a system
of independent efifectors, more or less such as we see in the muscu-
lature of the modern sponge, was differentiated. As a means of
bringing this musculature into more effective response, nervous ele-
ments developed in close proximity to the effectors. With the growth
of the musculature and the nervous system in volume and with the
consequent increase of metabolism, came the development of the cir-
culatory system and its dependencies, the respiratory and the excre-
tory organs. Thus the relatively simple body of the primitive meta-
zoan became gradually converted into that of the more complex type.
In all these changes no system of organs has done so much to unify
the metozoan body as the nervous system. If a sponge may be out-
lined as a metazoan whose organization concentrates on feeding and
reproduction, a human being may be described as one whose organi-
zation centers around nervous action. In such an organism the
nervous system is supreme ; and the rest of the body may be said
to do little more than aft'ord a favorable environment for this system ;
and yet, if the preceding account is correct, this most important
system originated som.ewhat late in the history of the metazoa and as
a relatively insignificant organ for the discharge of muscular activity.

Harvard University,
April 20, 191 1.

THE STIMULATION OF ADRENAL SECRETION BY
EMOTIONAL EXCITEMENT.

By W. B. cannon, M.D.
From the Laboratory of Physiology in the Harvard Medical School.

(Read April 2^2. rgii.)

Dreyer's demonstration that splanchnic stimulation increases the
content of adrenal secretion in blood from the adrenal veins has been
confirmed by several observers. Adrenal secretion therefore is under
control of the sympathetic system.

Major emotional disturbances indicate the dominance of sympa-
thetic impulses. In the cat, for example, fright causes dilatation of
the pupils, inhibition of the stomach and intestines, rapid heart, and
erection of the hairs of the back and tail. Do not the adrenal glands
share in this widespread subjugation of the viscera to sympathetic
control ?

To try this suggestion the inhibition of contraction in strips of
longitudinal intestinal muscle, sensitive to suprarenin i to 20,000,000,
was used as a biologic test. From the cat when quiet, and again
from the animal when excited by a barking dog, blood was obtained
by introducing, through the femoral vein, into the inferior vena cava
to the region of the liver, a small vaselined catheter. The blood thus
obtained was defibrinated and applied to the intestinal strip at body
temperature.

After an initial shortening the strip contracted rhythmically in
blood from a cjuiet animal. In no instance did such blood produce
inhibition. On the other hand, blood taken from animals after the
emotional disturbance, showed more or less promptly the typical
relaxing effect. As the emotional period was prolonged, the eft'ect
became prompter and more profound.

The view that inhibition of the contracting intestinal strip is due
to an increased content of adrenal secretion is justified for the fol-

226

19".] CANNON— STIMULATION OF ADRENAL SECRETION. 227

lowing reasons : ( i ) The effect was obtained in blood from the vena
cava near the liver when that from the femoral vein taken simul-
taneously produced no inhibition. (2) Removal of the adrenal
glands after tying the adrenal vessels resulted in a failure of excite-
ment to produce the eft'ect. (3) Adding varying amounts of adre-
nalin to inactive blood evoked all the degrees of relaxation that have
been observed in excited blood. (4) Excited blood which produced
prompt inhibition lost that power on standing or on being agitated by
bubbling oxygen. These conditions, together with the evidence that
sympathetic impulses increase the secretion of the adrenal glands,
and that during such emotional excitement as was here employed
signs of sympathetic discharges were observable in the animal from
the eye to the tip of the tail, prove that the relaxing eft'ect was due
to adrenal secretion.

Injected adrenalin is capable of inducing an atheromatous con-
dition of the arterial wall in rabbits, especially in elderly individuals,
and is also capable of evoking hyperglycemia with glycosuria. As
Ascher has shown by prolonged stimulation of the splanchnic nerves
prolonged adrenal secretion with maintained high blood-pressure can
be produced. In the light of the results here reported the temptation
is strong to suggest that some phases of these pathologic states are
associated with the strenuous and exciting character of modern life
acting through the adrenal glands. Two of my students, Shohl and
Wright, have recently shown that excitement of the cat results, in
all cases thus far examined (more than a dozen), in glycosuria.
Possibly in the wild state emotions were useful in providing material
for excessive muscular exertion that might follow, and that muscular
activity would utilize the sugar so that it would not appear in the
urine. This suggestion, however, must be put to further test.

PROC. AMER. PHIL. SOC, I,, I99 O, PRINTED JUNE 28, I9II.

THE CYCLIC CHANGES IN THE MAMMALIAN OVARY.

By LEO LOEB.

{Read April 23. igii.)

The observations which I wish to report to you are of interest
from several points of view :

1. The process upon which the sexual cycle in mammals depend
has been analyzed, and a regulatory mechanism was found to exist
within the ovary.

2. A striking illustration is presented of the fact that the struc-
ture of organs is in many instances at least not a definite one, but
varies in correspondence with the functional condition of the organ.

3. The accurate description of the normal cyclic changes in the
mammalian ovary serves as a basis for the investigation of the patho-
logical deviations which interfere with the natural course of the
sexual functions and may lead to a temporary or lasting sterility.

4. We found in the ovary structures which must in all probability
be interpreted as early stages of embryos developing spontaneously
parthenogenetically within the ovary and it is probable that the devel-
opment of these parthenogenetic embryos is related to certain phases
of the sexual cycle.

In the ovary of the guinea-pig definite and very interesting cyclic
changes exist which I made the object of my studies in the last few
years.

The mammalian ovary consists of two principal constituent parts,
namelv : First, large and small bodies lined by granulosa cells and
filled wath fluid, the so-called follicles ; and, secondly, the corpora
lutea. Both follicles and corpora lutca have only a brief existence;
thev develop to a certain point and then they degenerate and grad-
uallv disappear. The follicles contain the ova. At certain periods
of the sexual cvcle a few follicles that have reached maturity rupture.
The ova reach the Fallopian tubes and uterus and after fertilization

228

191 1-] LOEB— CYCLIC CHANGES IN THE OVARY. 229

by a spermatozoon form an embr}o in the uterine wall. Xew fol-
licles situated in the periphery of the ovary grow constantly to a cer-
tain size and then degeneration sets in. The lining granulosa cells
disintegrate and connective tissue grows into the cavity of the follicle.
The ova in these degenerating follicles undergo frequently matura-
tion and a few more or less regular divisions and then die. While
thus the majority of follicles degenerate, become atretic, before they
have reached maturity, a few follicles undergo certain progressive
changes and become mature. They may rupture and discharge the
ovum ; such a rupture is called an ovulation. The process connected
with ovulation causes a degeneration of all with exception of the
smallest follicles. These follicles grow and in the course of the next
six days they have reached that size at which degeneration may set
in. We find, therefore, degenerating follicles from the seventh day
after ovulation up to the time of the following ovulation. While
after the seventh day medium-sized follicles constantly degenerate,
new follicles grow and take the place of the degenerating disappear-
ing ones. It seems that it takes approximately ten days until some
of the follicles reach their full size.

A\'e may therefore distinguish two periods in the ovarian cycle:
First, the period of growth extending over the first seven days fol-
lowing ovulation, and, secondly, the period of equilibrium in which
new follicles take the place of degenerating ones. After the first
large follicles have appeared, it takes a few days longer until large
follicles become transformed into mature follicles that are ready to
rupture. We find, therefore, the first mature follicles to appear
approximately eleven to thirteen days after ovulation and it would
be natural to expect that about fourteen days after the preceding a
new ovulation should take place.

The sexual period — that is the period between two ovulations —
should therefore have a natural duration of approximately two weeks
in the guinea-pig. This is, however, not the case. The sexual
period in this species actually lasts about twenty to twenty-five days.
And this is due to the fact that a mechanism exists within the ovary
that prolongs the sexual cycle. In order to understand this mech-
anism, we must follow the fate of the ruptured follicle. A follicle

230 LOEB— THE CYCLIC CHANGES IN [April 22,

that has ruptured at the time of ovulation does not degenerate in a
similar manner as the other follicles do after they have reached full
size, but they grow in a remarkable manner and form a new gland-
like organ, the corpora lutea. Now these corpora lutea also degen-
erate after a period of growth that lasts approximately seventeen to
twenty days. In the corpora lutea resides the mechanism that pre-
vents a new ovulation. It is necessary that they degenerate before
a new rupture of follicles can take place. As long as they function
they prevent ovulation. The fact that the corpora lutea degenerate
when seventeen to twenty days old, explains why a new ovulation
takes place approximately every three weeks. If we excise the cor-
pora lutea at an early date after ovulation, a new ovulation occurs
very soon after mature follicles have made their appearance, approxi-
mately thirteen to fifteen days after the preceding ovulation. Under
these conditions, the normal sexual cycle is reestablished.

During pregnancy the life of the corpus luteum is prolonged in
consequence of the changes occurring in the uterus or developing
embryo during the period of gestation and in consequence of the pro-
longed life of the corpus luteum, a new ovulation is prevented during
the whole course of pregnancy. Toward the latter part of preg-
nancy, the corpora lutea again degenerate and directly after com-
pleted labor a new ovulation can take place.

Ovulation, therefore, depends upon three factors : First, upon the
maturation of ovarian follicles ; secondly, upon the time of degenera-
tion of the corpora lutea ; and. thirdly, upon less important, more or
less accidental conditions, as for instance, the process of copulation.
The third class of conditions accelerates in many (not in all) cases
ovulation, but it is not necessary for its occurrence. Even without
a preceding copulation, ovulation usually takes place, but in many
cases at a later date. Through what mechanism does the life of
the corpus luteum influence ovulation ? It might be conceivable that
the corpus luteum delays the maturation of follicles thus preventing
a rupture. My observations have, however, shown that an inhibiting
influence of the corpus luteum upon the maturation of follicles does
not exist. Mature follicles appear frequently during the life of the
corpus kitcuni, and especially during the period of pregnancy ; it

'911.] THE MAMMALIAN OVARY. 231

seems that pregnancy even favors the maturation of follicles. The
corpus luteum prevents, however, the rupture of the mature follicles.
Pregnancy as such does not prevent the rupture provided the corpus
luteum has been previously removed through excision.

The structural changes in the ovaries are rhythmical and so reg-
ular that a careful histological examination of these organs enables
us to decide within a certain limit of accuracy at what period of the
sexual cycle the animal had been at the time of the removal of the
ovaries.

Having established the normal cycle I turned more recently my
attention to its pathological deviations. It occurs in a certain num-
ber of animals — and I have observed this to happen among females
which showed no desire for copulation or in which notwithstanding
an accomplished copulation an ovulation did not follow — that the
follicles do not grow to maturity, but that they imdergo involution
before they reach their full size, and that all, or almost all the folli-
cles, become sclerosed, atretic, at a very early stage of their develop-
ment. Under these conditions, an ovulation is impossible and the
animal, in the ovaries of which such a deviation from the normal
cyclic changes exists, are at least temporarily sterile ; whether such
a pathological condition may ever lead to a permanent sterility,
future investigations must show. It will be readily understood that
here we have to deal with questions of the greatest importance to
the physiology of the sexual functions.

In order to appreciate thoroughly the conditions under which
such abnormalities in the sexual cycle occur, it is necessary to pro-
duce the subnormal development of the follicles experimentally. Now
it is of interest to know that such a premature involution of the
ovarian follicles can be produced experimentally by burning a certain
relatively small part of the ovaries with the thermocautery. The
remaining larger part of the ovary remains apparently perfectlv well,
the cells functionate but the energy of growth of certain cells is
diminished and subinvolution of the follicles with resulting temporary
sterility follows. A comparable condition can be produced in tumors
through heating, or through the influence of certain chemicals exerted
in vitro as I found a number of vears ago. Under such conditions

232 LOEB— THE CYCLIC CHANGES IN [April 22,

the tumors grow, but with markedly diminished energy. In both
cases, in the case of the tumors as well as of the ovaries, we have to
deal with a state of living matter intermediate between its full nat-
ural vigor and latent life ; we may regard it a state of partial shock
of cells, in which the growth takes place but with a considerable
decrease in energy. Besides the changes which I have just described,
additional processes of the greatest interest take place in the ovaries
of a certain number of animals and it is very probable that these
processes usually commence at the period following ovulation and
are therefore, in a certain sense, a part of the cyclic ovarian changes.
The process I refer to concerns an apparently spontaneous partial
parthenogenetic development of ova in the mammalian ovary, an
occurrence of which I obtained convincing proof only within the
last few^ months.

Some years ago I described peculiar structures that are found in
the ovaries of guinea-pigs, and I expressed the opinion that they orig-
inated in the ovarian follicles.^ \'ery soon after I had published my
observations, certain considerations suggested to me that these struc-
tures owe their origin to parthenogenetically developing ova.

In as much as at that time I had not yet seen early stages of the
structures referred to, I was unable to regard this hypothesis as sufili-
ciently founded to warrant publication. I continued, however, my
investigations in this direction, and recently I succeeded in finding in
two animals the desired early stages. They must be interpreted as
embryos developing parthenogenetically within the ovary of the
guinea-pig. We see in each case a chorionic vesicle with tropho-
blast, and plasmodia and syncytia penetrating into the neighboring
tissues. There is present also a structure which is probably to be
interpreted as a neural tube.

Aberrant blastomeres (remnants of dividing ova that failed to
participate in the embryonic development) cannot be seen in the
ovaries of guinea-pigs, and. inasmuch as the embryonic structures,
described in my former communication, are relatively frequent, oc-
curring in approximately ten per cent, of all guinea-pigs below the
age of six months, and, furthermore, inasmuch as they are situated

^ Archiv f. niikrosk. Anatomie. Bd. 65, 1905.

191 1.] THE MAMMALIAN OVARY. 233

in the cortex of the ovaries at a place where folHcles He normally
and are found within follicle-like cavities, they can only be derived
from ova developing parthenogenetically. Fertilization through sper-
matozoa can be excluded, inasmuch as the history of some of these
animals is known to us and precludes such an interpretation. It is
very probable that the parthenogenetic development sets in soon after
ovulation, the altered conditions in the ovaries at that time (varia-
tions in blood pressure, in intrafollicular pressure or changes in gas
exchange) supplying the necessary stimulus. This interpretation
agrees well with ni}- former observations concerning the parallelism
existing between the first segmentations taking place in non-fertilized
ova within the ovary and certain stages of atresia of follicles. -

It is also of interest to note that frequently these changes are
multiple, several ova undergoing parthenogenetic development in the
same ovary.

We may, therefore, conclude that in at least ten per cent, of all
guinea-pigs parthenogenetic development of the ova within the ovary
starts at some period of the life of the animal. The later stages of
these developing" embryos bear some resemblance to chorionepithe-
liomata, certain tumor-like formations consisting of proliferating
chorion tissue. During ovulation these structures are occasionallv
injured by hemorrhages and they are ultimately invaded and sup-
planted by the neighboring connective tissues.

These observations throw furthermore light on certain interesting
tumors that are especially found in the ovaries and testicles, namely :
the teratoid tumors and the chorionepitheliomata. My observations
are a strong argument in favor of the view that teratoid tumors that
are found in the ovaries arc not derived from misplaced blastomeres,
as Bonnet and Marchand believed, but that the older view is correct
according to which they are derived from parthenogenetically devel-
oped ova, an opinion which I, also, expressed on previous occasions.
The same statement can be made in the case of the chorionepithe-
liomata that occur in the ovaries and in the testicles. I believe that
the observations here recorded clear up the mechanism of the sexual

^ " On Progressive Changes in the Ova in Mammalian Ovaries," Jourual
of Medical Research, Vol. i, 1901.

234

LOEB— CYCLIC CHANGES IN THE OVARY. [April 22,

cycle in its essential aspects and they also make it extremely probable
that in a relative large proportion of mammalian animals a sponta-
neous parthenogenetic development of ova takes place at some period
during the life of the animal.

Department of Pathology,

Barnard Free Skin and Cancer Hospital,
St. Louis, Missouri.

THE SOLAR CONSTANT OF RADIATION.^

By C. G. abbot.
{Read April 21, 1911.)

If we had no eyes we should still know of the sun by the feeling
of warmth. The intensity of solar rays in any part of the spectrum
can be measured by delicate thermometry. Msion and photography
are both restricted within comparatively narrow limits of wave-
length, and each differs in its sensitiveness from wave-length to
wave-length. Ultra-violet, visible and invisible red rays, however,
all produce their just and proportional influences on the bolometer,
or thermopile. This is not universally known, and there are still
many who suppose we should distinguish between so-called actinic,
visible and heat rays. Doubt has been expressed, for instance,
whether bolometric measurements give true indications of the
intensity of those rays which promote plant growth. Such doubts
are not justified, and we may expect very valuable results in the
future from the application of the spectro-bolometer to the interest-
ing questions of radiation and plant physiology.

We use heat units to express the intensity of solar radiation.
The solar constant of radiation may be defined closely enough as
the number of degrees by which one gram of water at 15° centi-
grade would be raised, if there should be used to heat it all the
solar radiation which would pass at right angles in one minute
through an opening one centimeter square, located in free space,
at the earth's mean solar distance. Experiments were begun about
1835 by Pouillet and by Sir John Herschel for the measurement of
this great constant of nature. The investigation has been continued
by Forbes, Crova, A'iolle, Radau, Langley, K. Angstrom, Chwolson,
W. A. Michelson, Rizzo, Hansky, Scheiner and others. It is an
indication of the great difficulty of the research that entire uncer-

^ Published by permission of the Secretary of the Smithsonian Institution.

235

236

ABBOT— SOLAR CONSTANT Ol' RADIATION. [Ap'i' ->.

tainty as to the value of the sohir constant of radiation between the
limits of Pouillet's value, 1.76 calories, and Anj^strom's value, 4.0
calorics per s(|uarc centimeter per minute, i)revailed at the beginning
of the twenlieth century.

Professor Pringsheim has collected the following table- of solar-
constant values, as dcterniined by differer.t observers:

Year.

Ol.scivcr.

Calories.

Year.

Observer.

Calories.

1837

I'ouillet

1.8

1889

Peinter

3-2

1S60

llafTcn

1-9

1896

Vallot

1-7

1872

Forbes

2.8

1897

Crover and Ilansky

3-4

1875

Violle

2.6

iSqS

Rizzo

2.5

1878

Crova

2.3

1908

Sclieiner

2.3

1884

Langley

31

1908

Al)l)Ot and Fowle

2.1 ■'

1889

Sawelief

2.9

Tie omits Angstrom's 4.0. published in 1890 and withdrawn
in lyoo, but which is even yet sometimes ((uoted. lie omits also
Very's 3.1, pu])lishe(] in i<)Oi and independently obtained in 1910.
Kecentlv pu])lished values oi Kini])all, (Imwynski and others, ap-
proximately 2.0, are based in part on work of .\bbot and Fowle.

The determination of the solar constant involves: (i) correct
measurements of the heat e(|ui\alent of the solar radiati<^n at the
earth's surface; (J) a correct estimate of the losses which the rays
have suffered in the atmosphere before they reached the measuring
apparatus. We shall now discuss these two branches of the work.

Pouillel invented, about 1S35, his well-known instrument, the
pyrheliometer, for measuring the solar rays at the earth's surface.
Many criticisms have been justly made in regard to the accuracy
of this pioneer instrument, and atleiupts have l)een made by many to
improve on it, or to substitute a better. In our practice at the
Smithsonian Astrophysical Observatory, we have substituted a silver
disk for Pouillet's water chamber ; inserted a cylindrical bulb thcr-
mometer, radially instead of axiallw in the disk; provided a metal-
lined wooden chamber to screen the instrument from the wind; and
added convenient adjuncts for shading and exptx^ing the instru-

■ " Phvsik dor Sonne," p. 417.

" Til is value was expressed in terms oi a provisional scale of pyrlicli-
ometry which h;is since been proved too hii^h.

I9II-] ABBOT— SOLAR CONSTANT OF RADIATION. 237

ment.* Finally we have ceased to regard our instrument as giving
more than relative measurements. It is only a secondary pyr-
heliometer for convenient use. We standardize its readings hy com-
parison with an absolute pyrheliometer of another kind.

No known substance absorbs radiation perfectly at a single en-
counter. Kirchhoff showed, fifty years ago. that a hollow chamber
must absorb perfectly, because of the opportunity for an infinite
number of absorption encounters within it. W. A. Michelson, in
1894, invented a standard pyrheliometer including a hollow chamber
with a narrow opening for the admission of rays. The walls of the
chamber were bathed by a mixture of ice and water, and the heating
effect of the solar rays was measured by the amount of ice melted,
which was determined by noting the expansion in volume of the
mixture of ice and water.

Nearly ten years later, being ignorant of Alichelson's pyr-
heliometer (which was described in the Russian language), it
occurred to me also to employ a hollow receiving chamber. I pro-
posed to measure the solar heating produced in it by bathing its
walls with flowing water, and determining the rate of flow and rise
of temperature of the water. After experiments lasting inter-
mittently from 1904 to 1910, I am now satisfied that this device
has proved successful, and that we have truly an absolute standard
pyrheliometer. With the aid of my colleagues, Mr. Aldrich and
Mr. Fowle, two of these water-flow pyrheliometers were carefully
tested last year.^ Not only did they agree in measurements of solar
radiation, but test cjuantities of heat introduced electrically within
the absorbing chambers were accurately recorded by the methods
ordinarily used to measure solar heating. We believe of the abso-
lute water-flow pyrheliometer, it gives the intensity of solar radia-
tion at the earth's surface in calories per square centimeter per
minute within a probable error of 0.2 per cent. For convenience
we make our flaily observations with secondary silver-disk pyr-
heliometers, which have been standardized against the absolute
water-flow pyrheliometer.

* See Abbot, "The Silver Disk Pyrheliometer," Sniitlisoii. Misc. Coll.,
Vol. 56, No. 19, 191 1.

° See Abbot and Aldrich, Astrophys. Journal, Vol. XXXIII., 125, 1911.

238 ABBOT— SOLAR CONSTANT OF RADIATION. [April 21,

Having perfected the standard and secondary pyrheliometers
to a satisfactory degree of accuracy and durability, the first branch
of solar-constant work is accomplished by reading with the silver-
disk i)yrhcliometer at the earth's surface, and reducing its indi-
cations to calories per square centimeter per minute. We now turn
to the discussion of the second branch of the work, namely the
estimation of the transmission of the atmosphere for radiation.

Lambert and ]5ouguer showed almost simultaneously, about 1760,
that the transmission of light through a homogeneous medium may
be expressed by an exponential formula, such as :

E = E^a»\

Here E is the intensity transmitted, £(, the original intensity, a
the fraction transmitted by unit thickness, and m the actual thick-
ness of the transparent medium.

Pouillet applied Bouguer's formula to the atmosphere. As the
atmosphere is not homogeneous, but decreases in turbidity and
density from the earth's surface upward, this would seem at first
sight unjustified. But if we consider unit thickness to be the thick-
ness of the atmosphere traversed by a vertical beam, then as the ray
departs from the vertical, it still shines through every layer which
it did at first, and the path in every layer increases nearly as the
secant of the zenith distance of the ray. Under these circumstances
it can be shown that (subject to certain limitations to be mentioned)
the exponential formula given above should hold, if we consider E
to be the intensity at the earth's surface, E^ the intensity outside the
atmosphere, a the transmission coefficient for a vertical beam, and ni
the secant of the sun's zenith distance. °

Owing to atmospheric refraction, the fractional increase in path
of the ray, as the zenith distance waxes, tends to be greater for the
outer layers of the atmosphere than for its inner ones. On the
other hand, the curvature of the earth's surface produces an oppo-
site tendency. But for zenith distances less than 70° these effects
may be neglected, and they are hardly worth considering at 75°

"See Annals Smithson. Astrophys. Obscr., Vol. ![., p. 14, 1908.

191 1.] ABBOT— SOLAR CONSTANT OF RADIATION. 239

zenith distance.' Solar-constant determinations require no higher
values of zenith distance than these to be considered.

Radau and Langley proved the necessity of confining the atmo-
spheric use of Bouguer's formula to approximately monochromatic
rays. In general, for a reason which Lord Rayleigh has shown, the
transmission of the atmosphere increases gradually with increasing
wave-lengths. Thus in the violet the transmission for a vertical ray
to sea level may be 50 per cent., and for a deep red ray 80 per cent.
But besides this gradual change there are also spectral regions of
almost complete absorption by atmospheric oxygen, and by water-
vapor, so that in these regions the transmission approaches zero.
If we should disregard these differences, and determine the con-
stants of the exponential formula above, by pyrheliometric measure-
ments alone at dift'erent solar zenith distances, our result E^ for
the intensity outside the atmosphere must necessarily be too small.*

Langley was the first to act upon this, and 'to devise apparatus
and methods for measuring the energy and the atmospheric trans-
mission at all parts of the spectrum. For this purpose he invented
the bolometer about 1880, and automatic registration of its indica-
tions about 1890. As we now use it the bolometer comprises two
similar tapes of platinum, each about i cm. long, o.oi cm. wide and
o.ooi cm. thick. These are coated with lamp-black by smoking over
a camphor flame. They lie parallel to the spectrum lines, and
about 0.8 cm. apart. One tape may be shined upon by the rays,
the other can not. Hence the heat absorbed from a narrow region
of spectrum, usually about twice the extent comprised between the
D lines, raises the temperature of the exposed tape with reference to
the other. The two tapes and two resistance coils are combined to
form a Wheatstone's bridge, and the rise of temperature produced
as above stated deflects a sensitive galvanometer. The galvanometer
needle reflects a tiny spot of light on a photographic plate, which
moves vertically as driven by clock work. The same clock work
moves the spectrum slowly over the bolometer tape. In this way
may be produced in from eight to twelve minutes, according to the
spectroscopic outfit employed, a holograph, or spectrum energy

' Loc. cit., p. 59.
* Loc. cit.. p. 16.

240 ABBOT— SOLAR CONSTANT OF RADL\TION. [April 21,

curve, extending f roni about wave-length 0.30 ^i in the ultra-violet to
about wave-length 3.0/1, in the infra-red. Its ordinates are deflec-
tions of the galvanometer, proportional to energ>' in the spectrum,
and its abscissae are proportional to difit'erences of prismatic devia-
tion. The Fraunhofer lines, and great oxygen and water-vapor
bands, show as depressions in the curve. In order to eliminate dis-
tortions which are due to differences, for differing wave-lengths,
in the reflecting power and transmission of the mirrors and prism
used in the optical train, special investigations of the transmission of
the apparatus are made from time to time, and the curves corrected
accordingly.

In our ordinary practice, from six to eight holographs are taken
in a single forenoon, between the times when the sun's zenith dis-
tance is 75° and (say) 30°. The curves are measured at about
thirty positions, uniformly spaced in the prismatic spectrum. Each
group of six to eight measurements, at a single spectrum place, fur-
nishes means of computing from Bouguer's formula the transmis-
sion of the atmosphere for that wave-length, and also the ordinate
which would have been found there if the observations had been
made outside the atmosphere. The sum of the ordinates measured
on any holograph is approximately proportional to the total energy
of all wave-lengths observed. Similarly the sum of the ordinates
computed for outside the atmosphere is proportional to the total
energ}' there.^

In order to reduce the total energy, as determined bolometrically,
to calories per square centimeter per minute, the pyrheliometer is
read, while the spectro-bolometric work is in progress, on each day
of observation. Thus a factor is obtained for deducing from the
areas of the l3olometric curves the true heat units corresponding.^*'
A complete determination of the solar constant of radiation requires

" In the regions of great water-vapor and oxygen absorption the extra-
atmospheric curve is determined by interpolation between adjacent com-
paratively unaffected wave-lengths on either side> for we know that there is
no oxygen or water-vapor absorption of these bands produced in the sun, so
that they ought not to show in the extra-atmospheric curve. Small allowances
are also made for the energy of lesser and greater wave-lengths than any
observed.

^'' For further details consult Annals, Vol. IL

1911.] ABBOT— SOLAR CONSTANT OF RADL\TION. 241

about three hours of observation, under a cloudless and uniformly
clear sky. and about three days of computing.

We began to make solar-constant observations in Washington
at the Smithsonian Astrophysical Observatory, in October, 1902,
and continued them there whenever a favorable opportunity was
presented, until !May, 1907. In all this time we made only 44
tolerably satisfactory determinations at W'ashington, for cloudless
days were rare, and many days that promised fairly proved disap-
pointing, by reason of the appearance of smoke, haze or clouds.
Four important results came from the W^ashington observations.
First, no apparently good determinations yielded solar-constant
values above 2.38 of our then provisionally adopted scale of calories,
or 2.25 true calories. Second, the mean value in the true calories
from 44 determinations was 1.960. Third, the transmission of the
atmosphere was determined on many days, and for many wave-
lengths.^^ Fourth, a strong probability was raised by the results of
observations of 1903 that the sun is a variable star.^- This variation
seemed to reach 10 per cent, in its extreme range, but no tendency
towards a regular period was then found for it. A dependent
variation in terrestrial temperatures seemed indicated.

Primarily in order to make spectro-bolometric determinations
of the solar constant, suitable to test the supposed variability of the
sun, an expedition under my charge went out to ]\Iount Wilson in
1905, by invitation of Director Hale of the ]Mount W^ilson Solar
Observatory. The site proved excellent for the purpose, on account
of its considerable altitude, cloudless sky and freedom from wind.
Much aid and comfort was furnished by Director Hale and his
staff. The expedition was repeated in 1906, 1908, 1909 and 19 10.
We now occupy a cement observing shelter and living quarters there,
on ground leased from the Solar Observatory. Our observations
have generally occupied the six months, May 15 to November 15,
and in the last years we have made practically daily determinations
of the solar constant of radiation during this interval.

" Astronomers have not yet very generally availed themselves of the
accurate coefficients of atmospheric transmission obtained in our researches
for all parts of the spectrum, and from Washington, Mount Whitney and
Mount Wilson.

'^ See S. P. Langley, Astrophysical Journal, Vol. 19, p. 305, 1904.

242

ABBOT— SOLAR CONSTANT OF RADIATION. [April 2.,

It was thought doubtful by Langley, and others, if correct esti-
mates of the atmospheric transmission can be made, even by the
spectro-bolometric method of high and low sun observations. Lang-
ley, indeed, gave an argument tending to show that the values of the
solar constant thus obtained fall far below the true intensity of the
solar radiation outside the atmosphere. This argument, however,
seems to be unsound. ^^ In order to test the accuracy of the method
I made spectro-bolometric measurements on Mount Whitney (4420
meters elevation) in 1909 and 1910 simultaneously with similar ob-
servations made by Messrs. Ingersoll and Fowle, respectively, on
Mount Wilson (1800 meters elevation). In 1905 and 1906 solar-
constant measurements were made nearly simultaneously at Mount
Wilson and at Washington (10 meters elevation). It does not ap-
pear from these observations that there are any differences in the
solar-constant values depending on the altitude of the observer, and
not due to accidental errors of observations.^*

In illustration of this conclusion I give the results obtained simul-
taneously at Mount Wilson and Mount Whitney :

Date.

1909, Sept. 3.

Mount Wilson...
Mount Whitney.

1-943
1-959

1910, Aug. 12.

1-943
1.979

1910, Aug. 13.

1910, Aug. 14.

1.924
1-933

1.904
1-956

The very slight excess of the Mt. Whitney values is not large
enough to be significant.

We conclude that the solar-constant values computed from the
method of high and low sun observations do not depend on the
altitude of the observing station up to altitudes of 4,420 meters,
provided the sky conditions are satisfactorily clear and uniform.

Reducing values published in Vol. II. of the Annals to standard
calories at 15° centigrade, and including the mean values obtained
in later years, ^"' we have :

"See Aiiiuils. Vol. II., pp. 119-121.

'*As regards the Washington and Mount Wilson comparisons, see
Annals, Vol. II., pp. 99 and 102. Note that the provisional scale of these
Annals values is 5 per cent, too high.

'° Many of the values of 1910 are not yet reduced.

191 1.] ABBOT— SOLAR CONSTANT OF RADIATION. 243

Solar-Constant Mean Values.

Place.

Washington.

Mount Wilson.

Mount Whitney.

Date.

1902-1907

i9°5

1906 1908 j 1909

1910

1909

1910

Times observed

Mean value

44
1.960

59

1-925

1

62 : 113 95
1. 921 1.929 1.896

28
1.914

I

1-959

3
1.956

Our observations indicate as the mean value of the solar con-
stant of radiation :

1.922 calories (15° C.) per square centimeter per minute.

The observations having been obtained mainly near the time of
sun-spot maximum we think it probable that their mean is hardly
high enough to represent the average condition of the sun. We
incline to think this because it has been shown by Koppen, Nord-
mann. Xewcomb, Abbot and Fowle, Bigelow, Arctowski and others
that the earth's temperature is a little lower at sun-spot maximum
than at sun-spot minimum. This probable correction cannot exceed
one or two per cent.

There is another reason why our value of the solar constant may
be too low. \\''e have not been able to observe, even on ]^Iount
Whitney, any radiation beyond the wave-length 0.29/i, in the ultra-
violet spectrum. Whether the rays of less wave-length are oblit-
erated in the earth's atmosphere or in that of the sun we cannot
know, but we do know that ozone, which is perhaps formed in the
upper atmosphere, exercises powerful selective absorption beyond
wave-length 0.29/x. Hence it may be that we are forced to neglect
some radiation not quite negligible. It is very improbable that the
amount thus neglected exceeds i or 2 per cent.

As for the supposed variability of the sun, our determinations
strongly indicate that the so-called solar constant is not really a
constant, but fluctuates over a range of about 8 per cent. This
result is apparently the direct outcome of our observations, but the
question may well be asked if the apparent fluctuation is not due
either to the inaccuracy of the observations or to incorrect estimates
of the transmission of the atmosphere. If it were due merely to
accidental errors of observations, a gradual march, step by step, day
by day, from a low value to a high one and return woukl be the ex-

PROC. AMER. PHIL. SOC. L. I99 P, PRINTED JUNE 29, I9II.

244 ABBOT— SOLAR CONSTANT OF RADIATION. [April 21.

ception. We find it to be the rule, hence we must exclude accidental
errors as the main source of the apparent variability of the sun.
As for the other explanation suggested, we find no material differ-
ence in the result derived for the solar constant on a good day
whether we observe at sea-level, at one mile, or at nearly three
miles elevation, though the pyrheliometer readings on the ground
dififer by 25 per cent, between Washington and ]\Iount Whitney.
Hence we ma}- reasonably conclude that we do, in fact, correctly
estimate the loss which occurs in the atmosphere. The fluctuation
in the solar-constant results therefore seems to indicate either a true
variability of the sun, or else the interposition of meteoric dust, or
other cosmic hindrance to the passage of radiation from the sun to
the earth. These fluctuations, while not of regular periodicity,
generally run their courses within five or ten days.^*'

It is now proposed to test this conclusion by conducting solar-con-
stant measurements simultaneously at Mount Wilson and in southern
Mexico. If the results of a long series of daily observations at
these remote stations should agree, it would seem quite unlikely
that any apparently simultaneous fluctuations of the solar constant
of radiation could be attributed to terrestrial influences.

SUMM.'XRY.

Special apparatus, including the silver-disk secondary pyrhelio-
meter, the absolute water-flow p}rheliometer and the recording
spectro-bolometer, has been employed by the writer and his col-
leagues at Washington and Mount Wilson and Mount Whitney, to
determine the mean value of the solar constant of radiation, and
its possible fluctuations.

The observations, exceeding 400 in number, have been made in
all the years since 1902 to 1910. but most plentifully and accurately
in 1908, 1909 and 19 10. The mean value of the intensity of solar
radiation outside the atmosphere, at mean solar distance, is found
to be 1.922 (i5°C.) calories per square centimeter per minute, but
might prove i or 2 per cent, higher in years of less sun-spot activity.
The solar-constant values do not appear to depend on the altitude of

"See Abbot and Fowle, Astropliysical Journal, April, 191 1.

191 1-] ABBOT— SOLAR CONSTANT OF RADL\TION. 245

the observing station, up to the liighest altitude tested, 4,420 meters.
Fluctuations in the values proceeding step by step, day by day, from
higher to lower values and return, within a range of about 8 per cent,
usually occur in somewhat irregular intervals of from five to ten
days in total period. These fluctuations are thought to indicate a
true variability of the sun. It is proposed to test this conclusion by
daily observations extending over several months, and to be made
simultaneouslv in California and southern ^Mexico.

SELF-LUMINOUS NIGHT HAZE.

By E. E. BARNARD.

(Read April Ji, iqiiA

There is one phase of the night skies which does not seem to have
received much or any attention. It is the occasional presence of
self-luminous haze. This matter does not seem to be similar to tfie
luminous night clouds, " die leuchtenden Nachtvvolken." which were
observed by O. Jesse and others some twenty-five or thirty years
ago, and which were found to be clouds at such great altitudes above
the earth's surface (upwards of fifty miles high) that they received
the sunlight long after or before the ordinary clouds. The observa-
tions of O. Jesse were printed in the Astronoinische Nachrichtcn,
Bd. 121, pp. JT,, III ; Bd. 130. p. 425; Bd. 133, p. 131 ; Bd. 140. p.
161. In A. N., Bd. 140 (No. 3347), he gives a long list of altitudes,
determined by photograph}-, which range from 81 km. to 87 km.
The mean value given by the observations from 1885 to 1891 was
82 km. (52 miles). These clouds were seen in the northern hemi-
sphere onlv near the time of the summer solstice. In the southern
hemisphere they were seen at the opposite season. From his papers
it is clear that these sunlit clouds were in no way related to the
present subject, and I onl}- mention them to forestall any suggestion
that they were similar to the ones seen by me. The objects to be
described here were apparently at the altitude of the ordinary higher
clouds. They have been seen in all parts of the sky and at all hours
of the night. In a paper on the aurora^ I have previously called
attention to the frequent luminous condition of the sky at night.
This feature long ago impressed itself upon me. Indeed any one
who has spent much time under the open sky hunting comets, etc..
will have been forcibly impressed with this peculiarity. In most
cases this illumination has been due evidently to a diffusion of the

^ " Astrophysical Journal, 31, April, 1910.

246

1911.] BARNARD— SELF-LUMINOUS NIGHT HAZE. 247

general star light, perhaps by moisture in the air. This latter con-
dition is present as a whitening of the sky, which gives it a " milky "
appearance. At other times the sky is more or less feebly luminous,
but the luminosity is different from the other condition and is evi-
dently not due to a diffusion of star light. In reality the sky seems
to be self-luminous. Sometimes the whole sky has this appearance,
and at other times a large portion only. At times the illumination
is so great that the face of an ordinary watch can be read with no
other light than that of the sky. It is indeed seldom that the sky
is rich and dark. In any determination of the total amount of the
light of the sky the results must be uncertain because of the great
changes that so often take place in the amount of the illumination.
The self-luminous condition frequently occurs when no ordinary
indications of an aurora are present. It is, nevertheless, doubtless
of an auroral nature, for Professor Campbell has shown that the
spectrum of the aurora is essentially always present on a clear dark
night. {Astropliysical Journal. 2, August, 1895, p. 162.)

I have given an account- of the remarkable pulsating clouds of
light that are seen here occasionally and which usually, but not
always, have an easterly motion — generally southeast. They are
mostly confined to the northern half of the heavens. There is
another phenomenon that has been visible on a number of nights of
last year, and also in the present year, of which I have seen no
record. This consists usually of long strips of diffused luminous
haze. I believe that this is really ordinary haze, which for some
reason becomes self-luminous. It is not confined to any particular
region of the sky nor to any hour of the night. It always has a
slow drifting motion among the stars. This motion is comparable
wnth that of the ordinary hazy streaky clouds that are often seen in
the daytime. They are usually straight and dift'used and as much
as 50° or more in length and 3° or 4° or more in width. In some
cases they are as bright, or nearly as bright, as the average portions
of the Milky Way — that is, they are decidedly noticeable when one's
attention is called to them. They apparently are about as transpar-
ent as ordinary haze. Sometimes, when seen near the horizon, where

-Astropliysical Journal. 31, April, 1910, p. 210, etc.

248 BARNARD— SELF-LUMINOUS NIGHT HAZE. [April 21,

they may be quite broad, they have strongly suggested the " dawn "
or glow that precedes a bright moonrise. Their luminosity is uni-
formly steady.

The reason I speak of this matter as haze, and the reason I think
it is only ordinary haze made self-luminous, is because on one occa-
sion I watched a mass of it in the northwestern sky which was slowly
drifting northerly in the region of the great "dipper" of Ursa
Major as daylight came on. These hazy luminous strips had been
visible all the latter part of the night — new strips coming and going
slowly, sometimes several being seen at once. As daylight killed
them out I noticed, when the light had increased sufficiently, that
there were strips of ordinary haze exactly the same in form and
motion and occupying the same region of the sky. I am sure they
were the same masses that had appeared luminous on the night sky.
Alt impression, therefore, is that these hazy luminous strips were
only the ordinary haze which had for some reason become self-
luminous. I am specially certain that these masses are not luminous
as a result of any great altitude which might bring them within reach
of the sun's light, for they were frequently seen in such positions
that the sun's rays could never reach them. The sun or moon, there-
fore, had nothing to do with their illumination. It is also needless
to say that they are not related to the pulsating auroral clouds which
I have previousl}- mentioned.

I have not noticed this luminous haze in former years, though it
may have been present, and did it not seem unreasonable, one might
suspect some relation between this condition of the atmosphere and
the possible passage of the earth through a portion of the tail of
Halley's comet on 1910, May 19.

I will give here the observations which I have obtained of these
singular features. It seems to me that these objects should be ob-
served and a record made of the times of their visibility and their
motion, etc. It would be valuable to have records of them from
different stations to see if their luminosity is due to some general
condition of the earth's atmosphere at the time. It is not probable
that this luminosity is in any way due to local conditions. In the
records here given, it is possible that on one or two occasions an

191 1.] BARNARD— SELF-LUMIXOUS NIGHT HAZE. 249

aurora was also present, but I have tried to confine the accounts to
what I have called, and believe to be, self-luminous haze. They
were not seen previous to June /, 1910.

The Observations.

1910, June jd 13 h om. These diffused luminous masses were
seen in dift'erent parts of the sky. They were specially noticeable
near the southern horizon where the appearance was that of a definite
whitish light stretching along above the horizon for a considerable
distance. Long bands of this matter were parallel with the southern
horizon and above Antares. In the east a long strip 3° or 4° wide
stretched from a Pegasi to a Andromedae and beyond. This moved
slowly eastward. At I3h 30m another was passing through the bowl
of the great '" dipper " in the northwest with a slow easterly motion.
A very broad one was situated about i^°-2o° from the zenith to the
west. They were about as bright as the Milky \Va}' in Cygnus. I
waited until near sunrise, and could then see a long mass of ordinary
haze, reddish with sunlight, occupying the position of one of the
strips that was seen near the bowl of the " dipper," which had been
visible as a luminous mass until the dawn had killed it out. There
were other strips and masses of haze at different points in the sky
when the sun ro>e. I think it was these streaks and patches of dif-
fused haze that were luminous during the night. The}- appeared as
ordinary haze clouds in daylight. During the entire night there had
been no ordinary trace of aurora.

June 9. Though they were looked for several times none was
seen until about loh 30m or iih om. At iih 25m a long broad
hazy streak, as bright as the !Milky Way in Cassiopeise was seen
in the northwest. The lower end was in the " sickle "' of Leo near
the horizon. Its upper end was 15° below the polar star. From
a sketch at iih 25m the following points were taken which were
involved in the hazy strip :

■y. loh 5m 8 -j- 2I^5,

ot 9 5 8 + 49.

It extended beyond this latter point for quite a distance — roughly
to about

a /h om 8 + 67°.

250 BARNARD— SELF-LUMINOUS NIGHT HAZE. [April 21,

The stars were visible through it where it passed over them. The
motion was slowly to the northwest among the stars. Its width
was 5°. At I2h om a similar band passed over the " dipper " parallel
to the first one, evidently moving in the same direction. The first
one at this time had either disappeared or was too near the horizon
to be seen. At midnight I could read the time by my watch with
only the illumination from the sky, which was milky and whitish
or luminous.

June lod loh 45m. A long strip passed through Polaris and 5°
below the bowl of the " dipper." Its motion was towards the north
by east horizon, iih om a great number of luminous masses were
scattered over the western sky (and extending to the south) to
nearly as high as the zenith. These were mostly parallel strips
with some irregular masses. They extended from the horizon and
seen:ed to diverge upwards.

September 29. The sky was irregularly covered everywhere
with a kind of luminous haze which occurred in great areas and in
strips, with a few clear spaces between which were relatively dark.
They were more or less conspicuous. At 8h 25m a difl:'used lumi-
nous band stretched from Corona Borealis to the southwest horizon
— nearly north and south. This continued northerly nearly to the
pole and was difl:'used to the west. In the south and southeast for
20° above Fomalhaut to a Ceti was the upper edge of a luminous
mass of haze covering the southeast sky to the horizon. Other
diffused areas of this matter were visible at difi^erent points over
the sky. The wdiole sky was more or less luminous, but less notice-
able than the regions described above. By 8h 50m the broad lumi-
nous strip at Corona Borealis had drifted a little east among the
stars, but it seemed to go westward with them. At iih lom a watch
could be read by the light of the sky. This was one of the bright-
est of the luminous nights that I have seen. The matter seemed to
be only ordinary haze but luminous for some reason. There was
no trace of aurora. The sky on which the luminous haze was seen
was, at this time, brightened with a pale uniform illumination cover-
ing the entire heavens and nearly blotting out the Milkv Way. These
masses had very little motion. The sky was too luminous for long
exposures with a portrait lens.

191 1-] BARNARD— SELF-LUMINOUS NIGHT HAZE. 251

September 30. At 9h 15m for 10° above the east by north
horizon a broad luminous band 50° long was seen just aboye and
involving Aldebaran. It stetched to the south of the east point
and in brightness resembled the appearance produced by the moon
just before it rises. The light was soft, yet conspicuous. At
loh lom under Capella was a large soft diffused light — dift'using
to the east and beyond. This light was steady with no fluctuations.
Nothing of a similar nature was visible in the north or elsewhere.
The sky was dull and more or less luminous. At loh 55m the
illumination extended half way up to Aldebaran and the sky near
the horizon was luminous like moonrise. This extended from 25°
south of east to nearly due north, rising much higher under Capella
— a very soft and steady illumination. I2h om. The illumination was
feeble and diffused. At I2h 30m it was very feeble and mostly in
the northeast — scarcely noticeable. At this time dark smeary haze
was visible all over the south. Xo evidence of an ordinary aurora
was seen during the night. The sky was luminous all over, but
not so much so as on the twenty-ninth.

October i. There was a bright aurora.

October 2. 8h om. A pale illumination was seen in the low
north and also in the low east. The effect was probably auroral.

October 6. The night was more or less luminous and misty.

October 28. There was a luminous sky at night.

October 30. I3h om. The night was very luminous with fully
as much light as would be caused by a one quarter full moon. The
Milky Way was scarcely visible. Watch easily read by the glow
at I4h om. At i5h and i5h 30m a luminous haze covered all the
low northern sky as high as half way to the pole. This was not
strong and did not look like an aurora. It seemed simply to be
luminous haze.

November i, i2h 15m. The sky was remarkably luminous every-
where. In the north from the horizon to halfway to the pole the
sky appeared more luminous than elsewhere. No trace of an arch.
The illumination did not look like that from an aurora, but at
I5h 30m a strong auroral arch had formed.

November 10. i2h om. There was a great amount of luminous

252 BARNARD— SELF-LUMINOUS NIGHT HAZE. [April 21,

haze in the north and northwest. At I5h om a large mass 10° high
was visible in the northwest. Later there was a long diffused strip,
10° wide, which cut the Milky Way at right angles 20° above
a Cygni. It was 40° or 50° in length and did not fluctuate. Its
appearance was that of luminous haze. Below it was a region of
luminous haze that extended to the north.

191 1, February 28, 1511 30m. For 20° to 25° altitude all over
the east and northeast the sky was luminous with a soft auroral
light. There was no arch or intensification near the usual place
for an aurora. This was not due to the presence of the ]\Iilky Way
at that point.

March 2, 8h lom. A long mass of luminous haze 6° or 8°
broad was visible below (3 Leonis in the east. It diffused down to
the northeast horizon. It seemed to be brighter at times, but there
were no certain fluctuations of its light. It was not bright. 8h 50m.
The region of luminous haze was passing over Arcturus and moving
towards the east horizon. It was nearly horizontal and 30° long
with the north end the lowest. loh 45m. A long mass of luminous
haze was visible one half way from Spica to the southeast horizon.
It extended south as far as Corvus and inclined to the southeast
horizon. It was quite bright and steady in its light. All of the
southeastern sky strongly resembled the glow from an expected
moonrise. iih 35m. A strong glow from the southeast horizon
extended up to 15° or 20° above Jupiter — like a strong moonrise —
all along from the east to the south and dift'using upward. It was
conspicuously strong. By this time the sky was increasing in
luminosity. In the meantime there had been no trace of aurora
during the night. These were the first of the luminous masses of
haze that I had seen for a long time, except that of February 28,
when it appeared near the northeast horizon.

Since the above observations I have not seen any of this luminous

haze on the few clear nights that we have had in the absence of

the moon.

Yerkes Observatory,
April 4, 191 1.

191 1.] BARNARD— SELF-LUMINOUS NIGHT HAZE. 253

■ Note.

Since this paper was in type Mr. C. F. Talman, Librarian of
the Weather Bureau at Washington, through Dr. W. J. Humphreys,
has called my attention to a paper, Xo. 22, of the Publications of the
Astronomical Laboratory at Gronitlgen. " On the Brightness of the
Sky and the Total Amount of Starlight " by L. Yntema. Dr.
Yntema calls attention to the frequent luminous condition of the
sky and its efifect on determinations of the amount of starlight. In
section 14 of his paper, which is devoted to earthlight. he gives
numerous records of this illumination. There does not appear to be
any direct reference, however, to the main features of my paper — the
luminous hazy strips and masses.

]\Iay 15. 191 1.

SPECTROSCOPIC PROOF OF THE REPULSION BY THE

SUX OF GASEOUS AlOLECULES IN THE TAIL

OF HALLEY'S COMET.

By PERCIVAL LOWELL.
{Read April Ji, 191 1.)

1. The return of Halley's comet has been noteworthy chiefly for
the possibihty of employing upon it modern methods of instrumental
research. Since its last previous apparition have been devised those
two great engines of astronomic exploration, spectroscopy and celes-
tial photography. The former has afiforded us our first direct knowl-
edge of the substances composing comets, while the latter has given
us a means of easy and rapid registration of the visitant's appear-
ance. This is especially valuable in the case of a body as vast and
vague as a comet, free-hand drawing of which is peculiarl}- liable
to distortion.

During the last return of Halley's comet that body was sub-
jected at Flagstaif to investigation b\' both instruments simulta-
neously. One result of this was the detection that gaseous mole-
cules— in contradistinction to minute solid particles merely — are
directly repelled b}- a force emanating from the sun, presumably
the pressure of light. Previously this had been held impossible.
Schwarzschild had, as he thought, demonstrated mathematically in
an able paper that molecules of gas were too small to be thus aiTected
by the forces concerned and Arrhenius had adopted his deduction
and published it as a fact in his " Worlds in the Making." That
the bodies themselves would so soon refute this would not have been
deemed probable and invests the detection with the more immediate
interest. Incidentally we may remark that vSchwarzschild had since
given up his original opinion.

2. That the tail of a comet is due to repellant force exerted by
the sun is api)arent from the direction the tail takes. For that direc-

254

191 1.] MOLECULES IN THE TAIL OF HALLEY'S COMET. 255

tion agrees with what would be shown by particles leaving the
nucleus and travelling in hyperbolic orbits away from the sun, the
sun being in the full or the empty focus according to the speed of
recession.

Although the general fact is thus evident, to measure the reces-
sion directly is to obtain both an observatioral proof of it and also
something approaching an exact value of the velocity at a given
time and place. Accordingly I determined to do this in the case of
Halley's comet at its recent apparition. At my disposal were the
two hundred photographs taken of it at the Lowell Observatory
between April i8 and June 6. To obtain trustworthy results the
photographs to be compared must not be separated by too long an
interval, since with time a general commingling of the various par-
ticles takes place which not only renders particular decipherment of
different outbursts impossible but entirely alters the actual speeds.
In the case of Halley's comet this difficulty \\as enhanced bv the
unusual uniformity of the tail. Irregularities, bunches or knots
were rare : the tail presenting as a rule, a remarkably orderly deport-
ment, dishearteningly same. Among the many plates, however, I
was able to select a pair taken seriatim capable of recognition and
measurement. Some of these handles to ir.vestigation were in the
nature of bunches of matter, some of abrupt changes in its direction
looking like promontories along the general line of the tail. I chose
four of the more salient excrescences and selecting identical features
of them in the two negatives measured their respective distances
from the nucleus on the two plates. The first plate was exposed
from 9h 23m to gh 53m and the second from loh om to loh 53m,
so that the one followed directly on the other.

\\'hen the angular amounts of the changes in place of the several
knots were corrected for differential refraction and then reduced to
speeds, account being taken of the distance of the comet from the
earth and of the inclination to the line of sight of the respective
positions along the tail, the results came out as follows :

From these measurements the fact emerges unmistakablv that a
repulsive force directed away from the sun acted upon the particles
on the tail.

256 LOWELL— REPULSION OF GASEOUS -MOLECULES [April 21,
Tail of Hallev's Comet.

Knot

I

Knot

2

Knot

^

Knot

4

Angular Distance from the Nucleus to
the Point Measured in the Tail.

Velocity of the Point of the Tail Away
from the Nucleus.

13.6 miles a second
17.2 " " " .

19.7 " " "
29.7 " " "

3. \\'hile the series of direct photographs was being taken two
series of spectrograms were being carried on by Dr. SHpher, one with
an objective prism; the other set through a sht. The objective prism
ones recorded simultaneously the spectrum of the nucleus and head,
together with that of the tail out to about 11° from the nucleus.
One of them was got on Alay 23 at the same time as the photo-
graphs measured; while others were obtained on dates before and
after. Of the direct information afforded by these spectrograms of
the constitution of the comet an account is given in the extensive
monograph on the comet published by the Lowell Observatory.

4. But a third result was obtained by the unwitting collaboration
of the spectrograms and the photographs. While the photographs
were giving their pictures of the tail, the objective prism spectro-
grams were doing the like, with this difference that they recorded in
a row pictures of it in the several colors of the spectrum, sifting
out into a band those made by each separate wave-length of light.
They thus made it possible to tell to what wave-lengths the visible
appearances were due. For it became evident at once from the
spectrograms that all wave-lengths were not equally concerned. On
the contrary, there were in the spectral image several distinct tails
with spectral gaps between. By an analysis of the wave-lengths
yielding pictures of the tail was thus offered a diagnosis of the sub-
stances composing it. In this way it appeared that CO.,, carbon
monoxide, was the chief constituent of the tail ; CH^, marsh gas,
another; CX, cyanogen, a third component; and minute solid parti-
cles, giving a more or less continuous spectrum, a fourth.

That not one but a series of spectrograms was taken was impor-
tant. It not only gave us a constitutional history of the tail but it
showed the necessity of simultaneity in photographic and spectro-
graphic observations for comparative purposes. For the series

191 1.] IN THE TAIL OF HALLEVS COMET. 257

demonstrated that the constituents of the tail varied markedly from
one period to another. Thus from April 29, 1910, to May 7 the
spectrum of the tail was almost wholly emissive. On May 11 it
had changed to one nearly continuous, while on ]\Iay 23 it had be-
come largely emissive again and grew more so as time went on.

By comparing the photographic with the spectrographic series
of representations of the tail a striking fact came to light. To appre-
ciate this another point must be taken into account. In order to
compare properly a photograph and a spectrogram, both should be
made on the same brand of plate. Xo plate reproduces all parts of
the spectrum with eqiial intensity. One kind of plate will emphasize
certain rays and depreciate others ; the r.ext will reverse the estima-
tion. Great error will then be introduced unless the plates be
identical.

Xow the photographs measured were taken with a Brashear 5-in.
doublet, an excellent lens, on a Lumiere 2 plate. The rays regis-
tered by this plate extend from 3500 in the violet to 5 160 in the
green where the sensitiveness ceases. Indeed the effect would have
stopped sooner had it not been for the h_\ drocarbon emission at this
point. The light, therefore, of the photograph would be exactly
differentiated into its constituents by a spectrogram taken on a
Lumiere 2 plate. The only difference between the two would be due
to the absorption of the objective prism, an absorption relatively
greater for the violet than for the blue or green. This would work
as much on one kind of light as on another of the same refrangibility
and as the two different kinds we are considering, the emission and
the continuous spectrum, are about equally spaced in the region of
the violet, the correction needed on this account is small. We may.
then, directly gauge the character of the photograph's light by that
of the objective prism spectrogram taken on the 2 plate.

This w-e now proceed to do. On the exact date of the photo-
graph no 2 plate was used with the two objective prisms though we
have objective prism spectrograms on Cramer Iso. Instantaneous
on ]\Iay 2'^, 25, 26, 28 and 29. The nearest plate to the date in
question was on ]\Iay 29. Of this the best estimate gives for the
constituents of the light of the tail at a distance of 3° to 6° from
the head :

258 LOWELL— REPULSION OF GASEOUS MOLECULES [April 21,

80 per cent, of emission bands of carbon monoxide,
20 per cent, continuons spectrum,

the hydrocarbon emission being, at this distance from the head too
feeble to show.

Comparing now the spectrograms taken with a \'oightlander lens
and a Cramer Iso. Inst, plate on May 23, 25, 26, 28 and 29 we find
that the ratio of the two kinds of light varied in the direction of rela-
tively greater emission from the former to the latter date. On May
23 itself the plates are affected by moor light so that a direct com-
parison of the relative ratios is too difficult to be made a basis of
direct comparison, but that of May 28 gives for the ratios in the tail
3° from the head :

70 per cent, emission of carbon monoxide,

5 per cent, emission of hydrocarbons,
25 per cent, continuous spectrum.

Putting these facts together we shall not be far out of the way
in stating the ratio on May 23 of the emissive and continuous spec-
trum of the tail at a distance of from 3° to 6° from the head for
the 5 plate as

70 per cent, emission spectrum, CO and CHi,

30 per cent, continuous spectrum.

We have then this interesting conclusion : that the knots which
showed the action of a repulsive force exerted from the sun were
chiefly composed, not of solid particles, but of molecules of gases.

5. To clinch this deduction I next turned to comet Morehouse.
Catechized in this connection it not only corroborated the fact but
emphasized it. Before the time of measuring the velocities in the
tail of Halley's comet I had done the like for comet Morehouse, the
knotted character of its tail offering promising inducement. I was
not aware that Mm. Quenisset and Baldet, in France, and Professor
J. A. Miller, of Swarthmore, Pa., had measured photographs of this
comet in this manner previously and detected the same accelerated
motion away from the head which my own later measures showed.
My measures have also revealed why certain previous observers such
as Barnard at Yerkes and Campbell at the Lick had failed to find
such evidence.

igii.]

IN THE TAIL OF HALLEVS COMET.

259

Of comet ?iIorehouse this observatory possesses about sixty nega-
tives taken by Mr. E. C. Slipher. Among them are many pairs, the
one plate following the other on the same evening. From the assort-
ment thus offered I have selected two sets for measurement, the one
a pair taken on October 31, 1908, at 8h om zb to 8h 42m ± M.S.T. a-;d
from 9h 14m ±: to I oh 8m ± respectively ; and the other a triplet on
November 16. 1908, No. i being taken at 6h 25m to yh 13m; No. 2
at yh 24m to yh 50m ; No. 3 at 8h om to 8h 32m, respectively. I
chose four knots on one and five on the other with the following
results :

Tail of Comet Morehouse, October 31.

Plate I., Distance Knot
from Head.

Plate II., Distance Knot
from Head.

Difference I. and II.

Knot
Knot
Knot
Knot

I

2

3
4

22'.8

72'.7

95'- 5
I28'.4

24'. 4
76'. 2

99^-4
134^6

6^2

Tail of

Comet More

house, November 16.

Plate I.

Plate II.

Plate III.

Diff. I. -I I.

Diff. II.-III.

Knot I
Knot 2
Knot 3
Knot 4
Knot 5

48^7
63^4
79^7
87^8
211'. I

49'-9
65'.4
8i^6

89^3
215^.0

51^-4

66'.9

83^-5

90' -9

2i7'.7

1^2

2^.0

3^9

1^5

1/.9

2^7

6. It will at once be seen that both sets of plates show accelerated
velocity in the particles of the tail away from the head as the dis-
tance from the head increases. In the first set the acceleration is
fairlv uniform, while in the latter the velocity does not increase until
the distance out has become considerable. This afifords the reason
whv some observers have failed to detect the motion. It is at times
and in certain places masked. For this the following explanation
mav be oflr'ered : In the neighborhood of the head the several emis-
sions are violently contorted as a mere inspection of the photographs
show, and in consequence must be subject to collision with other por-
tions of the tail. Possibly they encountered here matter in space
which speaks unspeakably of motion other than that due solely to
repulsive force. If now an observer chanced to make his measures

rROC. AMER. PHIL. SOC. L. I99 Q, PRINTED JUNE 29, 19II.

260 LOWELL— REPULSION OE GASEOUS ^MOLECULES. [April 21,

at this inopportune moment he would naturally conclude that no
repulsion existed while in truth another motion was temporarily
obstructing it.

7. Lastly the spectrograms and spectroscopic observations of
Frost and Parkhurst. de la Baume Pluvinel and Baldet agree in
showing the light of the tail of Morehouse's comet to have been
due practically wholly to emission ; in other words to glowing gas.
Here, then, we have not only corroboration of the fact, brought
forward from study of Halley's comet, to wit : that molecules of gas
are repelled by the sun, but, from the light of the tail being com-
posed solely of gaseous molecules, any supposition that they were
not the cause of the visible effect, is entirely excluded.

We reach then this interesting conclusion: that molecules of gas

not only may be but demonstratedly are repelled by the action of

the sun and that though we have reason to suppose that minute solid

particles may be similarly impressed it is of the former not the latter

that we have direct proof at present.

Lowell Observatory,
April 10, 191 1.

THE NEW COSMOGONY.

By T. J. J. SEE.
(Read April 21, 1911.)

The results established in the writer's " Researches on the Evo-
lution of the Stellar Systems," Vol. II., 1910, have given a new basis
to our conceptions of the cosmogony. Instead of the traditional
doctrine of throwing off, we now have that of capture, which means
essentially that the nuclei originated in the distance and have since
grown by accretion as they approached the centers about which
they now revolve in greatly reduced orbits of small eccentricity.
Not only have we witnessed a radical change in the point of view,
but also in the method of research employed. And along with these
changes has come the introduction of rigorous mathematical and
dynamical criteria by which the mechanical principles involved may
be extended over an almost unlimited period of time.

Not the least important of the improvements recently introduced
is that resulting from a careful examination of the premises under-
lying our reasoning. Nothing is adopted from tradition, nor taken
for granted, nor from any authority however high ; but every ques-
tion is examined on its merits and from the very ground up. As the
subject is new it naturally follows that much still remains to be done ;
yet the general trend of nature's laws seems to be well established,
and cosmogony begins to assume the form of a true science. Ac-
cordingly it may not be without interest to the general reader to
summarize in one connected view the leading principles of the new
science of cosmogony, with brief analysis of the criteria by which
they are confirmed.

I. Babinet's criterion based on the mechanical principle of the
conservation of areas, by which we are enabled to calculate the
times of rotation of the sun and planets when expanded to fill the
orbits of their attendant bodies, as imagined by Laplace. This
enables us to say at once that the attendant bodies could never have

261

262 SEE— THE NEW COSMOGONY. [April 2,.

been detached by acceleration of rotation, as handed down by tradi-
tion from Laplace's original nebular hypothesis of 1796.

2. As the planets and satellites could not have been thrown ot¥.
they must have been captured and added on from without, or else
have been formed from the agglomeration of fine dust right where
they now revolve. This latter alternative, however, is easily shown
to be impossible, owing to the feeble mutual gravitational attraction
of small masses of matter under the stronger tendencies to di.spersion
by tidal action, which always exist near large centres of attraction.
There remains therefore no possible mode of origin for the planets
and satellites save that of capture, or addition to the system from
without.

3. When first captured the satellites must therefore have been
already of such considerable size that they were able to gather in,
and consolidate with their globes, numerous smaller masses revolv-
ing in the vortices about the planets. The collisions arising in this
process of the gathering in of smaller bodies by larger ones are
strikingly illustrated by the craters noticed in the face of the Moon,
which were formed by impact, the embedded satellites being in some
cases at least twenty miles in diameter.

4. Thus while the satelHtes were all captured,^ and were orig-
inally further from their planets than they are at present, they have
grown larger in the course of ages as they revolved in the resisting
medium about tlie planets, just as the earth and primary planets are
still growing larger by the impact of meteorites against their sur-
faces, as they slowly approach the sun. The earth sweeps up daily
1,200,000,000 meteors, and the amount of this dust is calculated to
to form a layer a millimeter thick in a century.

5. We know the satellites must have grown in mass since they
were captured, because they have been drawn nearer and nearer their
several planets, by increase of the central attraction, as in the cele-
brated problem of Gylden.^'' But if the mass of the sun has
increased, by the downfall of cosmical dust, so also must the mass

^ Since this was written the capture of Satellites has been independently
confirmed by Professor E. W. Brown, in an important paper in the Monthly
Notices of the Royal Astronomical Society for March, 191 1, p. 453.

'•'A. N., 2593.

191 1.] SEE— THE NEW COSMOGONY. 263

of the planet or satellite have been correspondingly augmented by the
same cause.

6. For whilst the decrease of the major axis of the orbit of a
satellite might result wholly from the growth of the mass of the
planet and satellite, yet the decrease of the eccentricity of a satellite
orbit can be explained only by collisions in the nebular resisting
medium. This cause and no other whatsoever will explain the
roundness of the orbits so characteristic of the solar system.

7. Accordingly as most of the satellites sufifered collisions suffi-
cient to reduce and well nigh destroy the eccentricities of their
orbits,- it necessarily follows that all these bodies should have their
surfaces indented by impacts with smaller masses, just as is shown
by the craters on the moon.

8. For whilst Oppolzer, Gylden and others have proved that the
growth of the masses by the downfall of cosmical dust would,
increase the central attraction and bring the bodies close together,
it is proved by the mathematical researches of Airy, Herschel, Leh-
mann-Filhes, and Stromgren, which I have carefully verified, that
this decrease in the major axis does not decrease the eccentricity.
Hence the decrease of the eccentricity is traceable to no cause what-
soever but the action of a nebular resisting medium, as held in my
" Researches." \'ol. II., p. 146.

9. The craters on the moon can therefore be due to no cause
whatsoever other than the collisions which our satellite has suffered
from other small bodies in space, and all divisions of opinion on the
subject are henceforth swept away forever. For as the other satel-
lites have had their orbits rounded up in nearing their several planets,
it is necessary to suppose the same cause to have acted also on our
moon, even if the eccentricity of the orbit in this case has not been
rendered excessively small.

10. This solution of the problem of the roundness of the orbits — -
the leading problem in the cosmogony of our solar system — is what
mathematicians call a unique solution. It reveals not only a possible,
but also the only possible cause of the extremely circular niove-

" In section 548 of his " General Astronomy," edition of 1904, the late
Professor C. A. Young remarks that the " almost perfect circularity of the
satellite orbits is not yet explained."

264 SEE— THE NE\V COSMOGONY. [April 21.

iitciit characteristic of the planets and satellites. The solution thus
possesses all the rigor of a theorem in geometry, and meets the
requirements of the most rigorous of the mathematical sciences.

11. The existence of planets beyond Neptune is indicated by the
extreme roundness of Neptune's orbit; for this shows that the
nebulosity was much too dense at that point for the system to ter-
minate at the present known boundary. Moreover, as I have shown
that the planets were originally connected with the comets, and the
comets recede to their home in a spherical shell thousands of times
the earth's distance from the sun, it necessarily follows that our
planetary system extends on almost indefinitely. Several planets of
considerable size must be assumed to revolve beyond Neptune, and
they may yet be discovered by observation or photography, though
at that great distance the practical difiliculties will increase, owing to
the feebleness of the sun's light and the slow orbital motion, which
will require exposures of the photographic plate extending over
many hours, and perhaps on successive days.

12. The planets have been built up out of cosmical dust, comets
and satellites ; so that all the matter now in the planets come origi-
nally from the heavenly spaces. This follows from the fact that
the nebular development is from the outside toward the center, the
formation always beginning in the distance and proceeding by accre-
tion as the bodies gravitate towards the sun, and revolve in ever
smaller and rounder orbits. This order of development is directly
verified by the phenomena of the spiral and ring nebulae; for here
the movement is proved to be towards the center, where the sun
develops for the domination of the system.

13. And just as our planets have been added onto the sun from
without, not thrown olT, as was erroneously taught for more than a
century by Laplace and his successors, so also will similar planets
have been formed by the same process about the other fixed stars.
Thus there are undoubtedly systems of planets about the fixed stars,
and they are habitable and inhabited like those revolving about
the sun. Moreover, the other suns have their systems of comets,
and their planets have captured systems of satellites as in our plane-
tary system. This grand conclusion rests on an incontestable basis
and is of transcendent philosophic interest.

191 1.] SEE— THE NEW COSMOGONY. 265

14. The causes which have operated in the development of our
solar system are thus general throughout the sidereal universe.
Everywhere repulsive forces are dispersing fine dust from the stars
to form the nebula", and the nebulae in turn are settling down and
whirling around to form stars with planetary systems about them.

15. Professor Barnard's magnificent photographs of the Milky
Way show that cosmical dust everywhere pervades the heavenly
spaces. And it is proved that variable stars are due chiefly to
attendant bodies revolving in resisting media. When considerable
bodies come into collision, as a large planet with a sun, the result
is a temporary star or Nova.

16. The new cosmogony thus embraces within its scope the chief
problems of the universe, and the dynamical causes assigned are
deduced from simple phenomena operating according to known laws
which are actually verified in the solar system. The arrangement
of the nebulffi on either side of the ^Milky Way is the natural out-
come of the operation of repulsive forces, the canopy of nebulse con-
gregating as far from the stratum of stars as possible. This assigns
a known cause for the great order of nature first brought to light by
the telescopic explorations of the elder HerscheHn 1785.

Like astronomy itself it is obvious that cosmogony is at once the
oldest and newest of the physical sciences. Having renewed its
youth by the introduction of definite principles and exact methods,
it has recently taken on such vigor that it promises to become the
most majestic of the sciences. Nothing is more worthy of the at-
tention of philosophers than the study of the great laws of the phy-
sical universe, and the marvelous processes of development by which
the beauty and order of the cosmos came about. This was the
great problem which gave rise to the development of the physical
sciences among the Greeks, and it will always occupy a position of
transcendent importance in the domain of natural philosophy.

U. S. Naval Observatory.
Mare Island, California,
April 3, 191 1.

THE EXTENSION OF THE SOLAR SYSTEM BEYOND

NEPTUNE. AND THE CONNECTION EXISTING

BETWEEN PLANETS AND COMETS.

Bv T. J. J. SEE.
(Read April 21, 1911.)

One of the most remarkable results of the writer's recent
researches on the origin of the solar system has consisted in the
development of a satisfactory proof that the primordial nuclei of
the planets were formed at great distances from the sun, and that
their primitive orbits were highly eccentric like those now described
by the comets ; so that in the last analysis it is shown that the two
classes of bodies are merged together, or rather that the planets
have been built up by the agglomeration of cosmical dust, in the
form of comets, and other fragments of matter, from our ancient
nebula. The following is a brief outline of the thread of argument
leading to this conclusion :

1. It is shown by the exact data supplied by Babinet's criterion
that not one of our planets could have been thrown off from the
sun, by acceleration of rotation, as imagined by Laplace in 1796, but
that the nuclei must have started in the distance and since neared the
sun, by insensible degrees, as the masses were gradually augmented
by precipitations from the surrounding nebular medium.

2. When it was thus demonstrated by exact calculation that the
premise handed down by Laplace is erroneous, our theory of
planetary genesis was placed on a new basis by the proof that the
roundness of planetary orbits is due to the secular action of a
resisting medium, which has reduced the size of the planetary orbits
and rendered them almost exactly circular.

3. In order to be so exactly circular, as they are now found to be,
these orbits must originally have been very large, and also highly
eccentric, like the orbits of comets ; the orbits accordingly have been
reduced in size by encounters with the other minor bodies, the

266

■911] SOLAR SYSTEM BEYOND NEPTUNE. 267

absorption of which also increased the masses of the planets
enormously.

4. If one asks for ocular evidence that the planetary bodies have
been in collision with smaller masses, this evidence is found in the
phenomena shown in the face of the moon, which was formerly an
independent planet, and is so small a globe as never to have devel-
oped water or atmosphere ; so that it is a kind of hermetically sealed
celestial museum, so near us in space that it serves for the illustra-
tion of the process of absorption and capture in cosmogony. The
type of collisions visibly illustrated by the dents in the moon's face
necessarily have occurred with all the planets ; but the moon as our
nearest planetary neighbor alone enables us to study the process of
accretion by collisions with bodies of all sizes, from particles to
satellites as large as twenty miles in diameter.

5. The obvious deposits of dust over the older lunar craters give
them an aspect of great age, and in many cases the outlines of the
craters are practically obliterated. In other cases newer craters are
formed over the older ones ; so that we can certainly infer by direct
observation that the moon has been built up by accretion, dust being
gathered in to be deposited over dust, and crater over crater. This
is the same process which we see at work on the earth, except that
the meteorites now swept up by our planet are generally small and
consumed in the air before reaching the earth.

6. Since the planets were begun as independent nuclei in our
nebula, and since augmented by the gathering together of an infinite
number of small bodies, such as comets, the matter of planets and
comets must necessarily be the same, for they are common products
of our ancient nebula. The planets have been built up by the gather-
ing in of satellites, comets and smaller particles of cosmical dust.

7. Xow we have pointed out that Neptune's orbit is too round
for it to be the outermost of the planets of the solar system. If the
resisting medium was dense enough at that great distance to produce
such extreme circularity in the motion of Neptune, there was
enough of the nebulosity beyond that planet to make several more
planets of comparatively large size. Thus it is certain that our
system does not terminate at Neptune, but extends on almost inde-
finitely. It is probable that in time we may be able to discover

268 SEE— SOLAR SYSTEM BEYOND NEPTUNE. [April 2,,

several trans-Neptunian planets ; but the recognition of these remote
bodies will be difficult, owing to their slow motion and the faintness
of the sun's light at that great distance.

8. The notable expansion of our ideas of what constitutes a
nebula will thus be of great practical use in the progress of astron-
omy. The overthrow of tlie theory of Laplace is only a small part
of the service to science brought about by the discovery of the true
laws of the development of our system. As the comets recede to
distances amounting to thousands of times the earth's distance from
the sun, so also must embryo planets be imagined to bridge over the
gap heretofore separating the planets and comets. And we may
imagine planets to extend to at least ickd. perhaps 1,000 times the
earth's distance from the sun. Some of the comets may go 100
times further yet, but at such great distances we can never know
much about their motions in these remote regions of space.

9. When we contemplate the vast extent of our primordial
nebula implied in the distances to which the comets recede, and
remember the large apparent areas covered by many other nebulas
in the sky, we see that our solar nebula evidently was of the ordinary
type, and that it certainly was not a gaseous mass in equilibrium
under hydrostatic pressure and extending only to the orbit of
Neptune. Of course all these old doctrines of Laplace are now
quite abandoncfl, but they long deceived us. and kept cosmogony
in a stationary condition for over a century.

10. The origin of the primordial nuclei in the distance is a neces-
sary consequence of the working of planetary bodies towards the
dominant center of attraction — the sun. Hence the formation of a
system of planets is necessarily from without inward, just the
reverse of the traditions handed down by Laplace. This harmonizes
perfectly with the new theory of the spiral nebulae, which makes the
ring nebulas particular cases of the more general spiral tendency.
The formation in all cases is from the outside towards the center.
Planets form in all nebulae, and since small bodies approach the center
more rapidly than large ones, under the action of a resisting medium,
it follows that the planets thus capture systems of satellites such as
we observe attending the planets of the solar system.

U. S. Naval Observatory,
March 7. 1911.

THE SECULAR EFFECTS OF THE IXXREASE OF THE

SUN'S MASS UPON THE MEAN MOTIONS, MAJOR

AXES AND ECCENTRICITIES OF THE

ORBITS OF THE PLANETS.

Bv T. J. J. SEE.
{Read April _'/, 1911.)

In the days of Newton, Lagrange and Laplace, it was assumed
that the formation of the planetary system was essentially complete,
and the sun's attraction rigorously constant from age to age ; and it
was scarcely deemed necessary to consider the secular efit'ects of
slight modifying causes such as the downfall of cosmical dust upon
the bodies composing the solar system. But the progress of the past
century has shown that the Newtonian hypothesis of a constant
mass and a central attraction depending wholly on the distance, but
not on the time, is at best a very rough approximation to the truth;
for in addition to the downfall of cosmical dust upon all the bodies
of our system, it has been shown by the researches of Arrhenius,
Schwartzchild and others, that the sun especially is losing finely
divided matter under the action of repulsive forces such as we see
illustrated in the streamers of the corona and the tails of comets.
In our modern studies of the orbital motions of the heavenly bodies,
therefore, we have to take the central mass as variable with the
time, and consider the small secular changes which will follow from
a variation of the central attraction incident to a gradual change of
mass.

These questions have been treated in some form by many of the
successors of Newton ; and even this great philosopher himself in
one case supposed that the central mass might be varied by a comet
falling into the sun.^ Laplace devotes considerable attention to the
secular equations for determining the eltects of the decrease of the
sun's mass due to loss of light, then supposed to be of corpuscular

* " Principia." Lib. III., last proposition.

269

270 SEE— SECULAR EFEECTS OF THE [April 21,

character.'- The modern discussions based on the analytical methods
of Gylden are, however, much more satisfactory than those of the
age of Laplace; and I propose to give a brief account of them,
chiefly with a view of summarizing the state of our knowledge, and
of removing some inconsistencies which may mislead those who are
unfamiliar with the literature of the subject.

For example, in the late Professor Benjamin Peirce's " Ideality
in the Physical Sciences," Boston, 1881, p. 131, the following
curious statement occurs :

The constant increase of the solar mass would have an influence on the
planetary orbits. It would diminish their eccentricities, according to a law
of easy computation. Hence it is possible that the orbits of the planets may
have been originally very eccentric, almost like those of the comets ; and
their present freedom from eccentricity may have resulted from the growing
mass of the sun. What modification of the nebular theory may be involved
in this supposition cannot easily be imagined, without the guidance of some
indication from nature.

This statement is misleading and erroneous, and the only way I
can explain its appearance in the writings of Peirce is by the fact
that his last lectures were prepared when he was at an advanced age
and in ill health ; and thus it is probable that some confusion
occurred. Quite recently an analogous confusion has appeared in
the Asirononiischc Nachrichioi, Xo. 4454, in a short article by Dr.
R. Bryant, on the secular acceleration of the moon's mean motion.

In order to place before the reader a summary of the chief
investigations bearing on the problems now under discussion we cite
the following papers :

1. " The Problem of the Newtonian Attraction of two Bodies
with masses \'arying with the Time," H. Gylden (A. N., 2593).

2. ■' Ein Specialfall des Gylden'schen Problems," J. Mestschersky
(A. X., 3153 and 3807).

3. " I'eber Central Bewegungen," R. Lehmann-Filhes {A. N.,
3479-80).

4. " Note on Gylden's Equations of the Problem of Two Bodies
with Masses \"arying with the Time." E. O. Lovett {A. N., 3790).

5. " l/eber die Bedeutung Kleiner Massenanderungen ftir die
Xewtonsche Central Bewegung," Dr. E. Strtimgren (A. .V., 3897).

■ Mecanique Celeste, Liv. X., § 20.

39II-]

LXCREASE OF THE SUX'S MASS.

271

The last of these papers is the most important, since it supple-
ments and extends the results of the earlier investigators. Professor
Stromgren's method is one of great generality and appears to be the
most satisfactory yet devised; and we shall base our brief discussion
■chiefly on this paper.

If cr be a very small quantity, and (pit) some function of the
time, the original unit of mass becomes i -|-o-<^(n. and the differ-
■ential equations of motion become

d^y

dt

r,+k\\ + o-(^(o] ';3 = o ;

(I)

where k- is the gravitation constant, and the mass is unity at the
initial epoch ^ = o.

The new constant of areas becomes

dv

dx

Other formulas of interest are:

la = i\(T<^{t) — 2d\<j I 0'(/) jit ,
- = - [i + 2I/. [ie] cos i{e + ;// — tt)]

(3)

(4)
(5)

And finally after a careful investigation of all effects due to
errors of the first order of the disturbing force, (T(f>(t), Stromgren
iinds :

8a

8e =

= — aa\

/ + 2 - (sin E — sin E

41

I — r

(T (sin E — sin E^ ,

s/\ — e^

CTT = a(cos £ — COS E) .

en ^

(6)

272 SEE— SECULAR EFFECTS OF THE [April 21,

Here )i is the mean motion and E the eccentric anomaly. It will
be seen from the first of equations (6) that the semi-axis major is
diminished by a secular term depending on t, and by a periodic term
depending on the difference of the sines of the angles E and -Eg, or
the position in the orbit. Thus the mean distance is subjected to
both periodic and secular variation.

In the case of the eccentricity, however, the second of the equa-
tions (6) show's that there is no secular term, and only periodic
changes occur. A similar remark applies to the longitude of the
perihelion as shown by the third equation -of (6).

We conclude, therefore, from Stromgren's careful analysis that
there is no secular decrease in the eccentricity due to a steady
growth of the central mass; and that the views expressed by Peirce
and Bryant are due to confusion, or to some error in the chain of
reasoning.

This conclusion accords with the result reached by Professor
Lehmann-Filhes, in paper Xo. 3,'' cited above. For Lehmann-
Filhes shows that

c cos TT = r„ cos TT,, + periodic terms, 1
e sin TT^ (',, sin tt,, -|- periodic terms : J

and remarks that when the attracting mass slowly increases the
orbit slowly narrows up, but yet always remains a similar conic
section. He adds that this is true for any eccentricity whatever.
The results of Lehmann-Filhes and Stromgren, each worked out
independently of the other, and with much detail, are therefore in
entire accord; and as Str(">mgren's development is given in full, and
every step in liis analysis is quite clear, we must reject the conclu-
sions of Peirce and Bryant as not v.'ell founded.

This concllusion that the steady increase of the central mass will
not diminish the eccentricity also confirms the results reached by
Airy* and by Sir John Herschel.-^' For these eminent authorities
show that a central attractive disturbance decreases the eccentricity
as the planet moves from the perihelion to the aphelion, but increases

^Cf. A. N., 3479-3480.

* ■' Gravitation," pp. 50-51.

'"Outlines of Astronomy," tentli edition, 1869, p. 463.

19".] INCREASE OF THE SUN'S MASS. 273

it correspondingly in going from the aphelion to the perihelion ; so
that only periodic changes of the elements c and tt occur.

Accordingly it foUows that the only possible cause which could
have diminished and practically obliterated the eccentricities of the
orbits of the planets and satellites is the secular action of a resisting
medium, as fully set forth in Volume II. of my " Researches on the
Evolution of the Stellar Systems," 1910. Increasing the central
mass accelerates the mean motions, and thus hecomes very sensible
in the theory of the motions of the planets; but it has no eftect on
the shape of their orbits. The almost circular form of the planetary
orbits, therefore, may be referred to the secular action of a resisting
medium and to no other cause whatsoever.

This result is of no ordinary interest, since it refers the round-
ness of the planetary orbits to but a single physical cause, and gives
us what mathematicians call a unique solution of the leading problem
of cosmogony. For Babinet's criterion shows beyond doubt that
the "planets never were detached from the central bodies which now
govern their motions ; and the argument given in A'olume II. of my
" Researches " proves that all these bodies were formed in the
distance and afterwards neared the central masses about which they
now revolve. The demonstration of the true mode of formation of
our solar system is therefore supported by the necessary and suffi-
cient conditions usually required in mathematical reasoning; and we
may say that the laws of the formation of the solar system have been
confirmed by mathematical criteria having all the rigor required in
the science of geometry. This generalization will, I think, add not
a little to our interest in the geometry of the heavens; and it is
equally worthy of the attention of the astronomer, the geometer and
the natural philosopher, who so long struggled to unfold the wonder-
ful process involved in the formation of the planetary system.

U. S. Naval Observatory,
Mare Island, California,
March 20. 191 1.

ON THE SOLUTION OF LINEAR DIFFERENTIAL EQUA-
TIONS OF SUCCESSIVE APPRONIMATIONS.

Bv PRESTON A. LAMBERT.
(Read April 30, 191 1.)

The object of this paper is to apply to the solution of linear differ-
ential equations, both ordinary and partial, the method of expansion
into series used in the solution of algebraic equations in the papers
read by the author before the Philosophical Society in April, 1903,
and in April, 1908.

Let the given differential equation be

f dy d'y (t\v\

o.

The method of solution consists of the followirg steps :
(a) Break up the left-hand member of the dift'erential equation
into two parts.

and

/ dy d\v d"y\

-^\''''^''dv'dP^ ■'■'dr^)

j\^^y^ dx • dx-' '"' dx")'

such that the first part equated to zero can be integrated by some
known method, and multiply the second part by a parameter 5", inde-
pendent of .r and 3'. Replace the given equation by

, . rf dy d^y d"y\ ( dy d'y d"y\

(6) Assume that

(3) 3' = Vo + y\S + r.^-^' + yS-^ + r A* + • • •

makes equation (2) an identity.

274

191 1.] LINEAR DIFFERENTIAL EQUATIONS. 275

(c) In this identit}- arranged according to the ascending powers
of S equate to zero the coefficients of the different powers of S.

(d) Solve the dift'erential equations thus obtained in regular order
for Vo.Vi,3'o,3'3, V4. •■••

(e) Substitute these values in ( 3 ) and make 5" unity. The result-
ing value of _v, if it contains a finite number of terms or if it is a
uniformly convergent infinite series, is a solution of the given dif-
ferential equation.^

The method of solution of linear dift'erential equations as here
outlined does not seem to occur in mathematical literature except as
developed by the author.

The method will be exemplified by applying it to two dift'erential
equations, important in mathematical physics — Bessel's equation, a
second order ordinary dift'erential equation, and Fourier's equation
for the flow of heat, a second order partial dift'erential equation.

Bessel's equation is

X'

Replace Bessel's equation by
and assume that

y = y\> + y\S + y,5-^' + v..^' + y,S' + • • •

makes the latter equation an identity.

When arranged in ascending powers of 5^ this identity is

o^j'o ' ,^ ^ , .^_y^ 5^' -f • • • = o.

dx^ , "^ dx' "^ dx~

'^O ^1 ^2

dx dx dx

^ This method gives a formal solution of non-linear differential equations,
but up to the present time the author has been unable to test the resulting
series for convergency.

PROC. AMER. PHH,. SOC. L. I99 R, PP INTED JUNE 30, I9II.

276 LAMBERT— ON THE SOLUTION OF [April 2^.

Equating to zero the coefficients of the powers of 5" in this identity,
there result the following differential equations for the determina-
tion of yo,yi,y2>yz> ••••

The equation in v,, is a homogeneous linear differential equation
and its solution is

Substituting this value of y,, the equation for determining y^
becomes

ax'- ax ^

This equation becomes exact when multiplied by .t'"""\ The
resulting equation integrated gives a linear equation of the first order,
the solution of which is

-^'1 ^ 2\n^) "^ 2\n- i) ■

Substituting this value of a'i in the equation for determining y^
and proceeding in the same manner

V = 1

2*. 2 !(/^ -I- i)(« + 2) ^ 2'- 2 !(;/— i){n — 2)

In like manner

_ Ax''+^ 5;t'-"+«

J', = 2^7! (;r+ i)(« + 2){n + 3) "^ 2''.3!(^/- i)(«- 2)(^z-3)'

and so on.

191 1.] LINEAR DIFFERENTIAL EQUATIONS. 277

Substituting these values of 3V,. Vi, jv. Ts, • • • in

y = Vo + y\S + yS^ + V3^^ + v,^* + • • •

and making 5" unity,

A
+ 2) 2*-T!

I x^ ^

V I x"^ I x^

(;z+ i){n + 2){n+ 3) 2^3!

+

^ I ;tr

+ .5.ir-" I + -2 +

2 T ,.4

;/ — I 2^ (« — I )[n — 2) 2* • 2 !

I x^

+ (;,_ i)(;,_2)(;/-3)^^y!-^

]■

When n is not an integer the terms of both series in this value
of y continue indefinitely according to the law of formation which
inspection makes evident, both series are uniformly convergent ex-
cept when .r=:0, and both series are solutions of the given dififer-
ential equation.

When n is a negative integer the law of formation of the terms
of the first series changes after the (?;)th term and when n is a
positive integer the law of formation of the terms of the second
series changes after the (;Oth term. The second case will be con-
sidered.

W^hen ;/ is a positive integer the {n)xh. term of the second series is

Bx^-^

^'"-' ^ 2-'"-^'(;/ _!)!(;/_ I)! •

Substituting this value of 3'»^i in the differential equation for
determining 3',,,

ax^ ax - " - " '

and solving for y„ by the method used in solvir.g for 3'i,3'2-3'3, •••,

A= ^^-jiiijr^.y ['' log '^- - 27J •

In determining 3'„xi.3'»,-o.3'».3, ••■, the second term in the bracket

278 LAMBERT— ON THE SOLUTION OF [April 20,

gives the terms of the first series in the vaUie of y multipHed by a
constant. This new series is combined with the first series in the
value of y.

The first term in the bracket gives

^'n+l 2^"~

^«!(;/- I)! [~ 2Xn + i) + ¥{;r+~T) \ ^ "^ «T~i )\ '

_ - B r ,1-"+-' log X

J'n+2 = 2^'^'n\{n- I)! [ 2 ! 2\n + i)(;7T^)

\ ^ "*" 2 "*" ;/ + I ;74- 2 /J

2 ! 2\;i + i)(;/ + 2)

The solution of Bessel's differential equation when // is a positive
integer is therefore

J' = ^,f" I , + 7 ry-

4

4- 2) 2*.2l

I x'

{11 + i)(;/ + 2)(« + 3) 2''.3!^

r I A'2 I x^

y + -^-^;^j -2 + (;^ _ i)(;^ _ 2) 2^^721

i>lr" log x r I ,1-^ I .1'*

~ 2^"-Vr!(;/ -^lyi L^ ~ n + I 2- "*" (7; + i)(;rT2) 2*.2 !

]

]

(„+ !)(;,+ 2)(;/ + 3) 2^.3!
~ 2^"-'n\{n- i)! [ ;7T~i V ^ "^ ^'^ I / 2"

- (« + i)(n^2)y "^ 2 "^ «> I "^ «+ 2 j 2*. 2 ! "^ ■ ■ ■ J ■

This is also the solution of the ditferential equation when 11 is a
negative integer.

I91I.]

LINEAR DIFFERENTIAL EQUATIONS.

279

Fourier's partial differential equation for the linear flow of
heat is

= IC

dt
Replace Fourier's equation by

dx

dV _ d^V

and assume that

makes the latter equation an identity.

When arranged in ascending powers of S this identity is

^0

a/

+

dt

5 +

dt

K

- K

^2

S^ + ... = 0.

Equating to zero the coefiicient of the powers of 5" in this identity,
there result the following partial differential equations for the deter-
mination of Fq, F^, Vo, Fg, • • •,

= o,

^0

dt

dj-^'dx' = ''^

These partial differential equations solved in regular order give
V, = c^{x), l\ = 4>%r){Kt), F, = c/>-(-r)^\

f^3 = </> ('^)-Yr' ••••

Substituting these values of F^, F^, F„, Fg, ... in the assumed
value of F and finally making 5" unity, there results

{A) F= 4>{x) + r{-r){Kt) + <t>'\x) ^' + r\^) ^' + • • . ,

280

LAMBERT— ON THE SOLUTION OF

[April 20,

which is a solution of Fourier's equation for all values of <f>(x) for
which V either contains a finite number of terms or is an infinite
series uniformly convergent both in .r and in t.

The following table shows several values of <^(.v) and the cor-
responding solutions of Fourier's equation.

I (i) <f>(x) = A,

(2) <f>{x) = A.V,

(3) <^W = ^-^^

(4) (f){x) = A sin {nx),

(5) <^('t') = ^ cos {71X),

(6) 4>{x) = Ae^%

(7) <^{x) = Ae-\

(8) 4>{x) = Ae"' sin {?ix).

V= A,

V= Ax,

F= A{x^ + 2 A?),

]^ = Ae-''-'^' sin {nx).

V=Ae-

{nx),

V= Ae-"'+"'''',

V= Ae""" sin (//.r -(- 211^ Kt).

It will be noticed that in these solutions ^(.r) is the value of V
when t=o, that is F^</)(.r) is the initial heat distribution.

It will also be noticed that in all these results x may be replaced
by X 4" 0" This statement is true of the results in the several fol-
lowing tables.

If Fourier's differential equation is replaced by

Ct OX'

and the assumption made that

makes this equation an identity, this identity arranged in ascending
powers of 5" is

K

dx^

+ K

dx^

dV
'^ 0

dt

S + K ^^2

dx'

dt

_dV,
dt

S' + ■•' =0.

Equating to zero the coefficients of the powers of 5" in this
identity,

I9II-] LINEAR DIFFERENTIAL EQUATIONS. 281

Solving these partial differential equations in regular order for
Fq, fj, Vo, v., ■■■, substituting these values in the assumed expres-
sion for V, and finally making 6^ unity, the result

F= <^(/>' + ^ <f>'(t) '^' + ^, <}>'V) f^+'--
(B)

is a solution of Fourier's differential equation for all values of
<^(^) and 6(t) for which V either contains a finite number of terms
or is an infinite series uniformly convergent both for x and for t.
Solutions of the differential equation when (j>(t) =o correspond-
ing to several values of ^(0 are as follows —

II </>(/) = O,
(i) d{i)=A, V=A,

(2) d{f) = Af, ^=^{' + ^)'

(3) ^(/) = At\ F= A (/^ + J.' + ^, ) ,

2 \{2Kt) \\{2Kif

3-y^ 1

'^ t\{2Ktf "y
(5) e(t) = ArK V=-^^,

3

2 ! 2A7 ' 4 ! {2KtY

3 '^' ]

^,)eit) = At-K V=At-^[.--^-^^ +

6 ! {2Kty
3-5 ■«^*

4! (2A'/)2

3-5-7 __^'
6! {2Ktf "^ ■

]

282 LAjVIBERT— ON THE SOLUTION OF [April 20,

sin (;//) -I- cos nt — j-

--^sin(;//) ^-, J,

(9) ^W = A log /, F= ^ l^log / -f ^ ^^ - ^~- -^

2 X^ 2 • 3 -tr^ ~|

"^ i^3 6T ~ KU' sT ^ ■ ■ ■ J '

(10) d{i) = At', V= Ac-^i + I -2T + f^ fl + • • •]•

It will be noticed that in these solutions V =^0{t) is the heat dis-
tribution when ^■ = o.

Solutions of the differential equation when 0(t) =0 correspond-
ing to several values of (j)(t) are as follows:

III 0{t) = o,

(i) <l>{t) = A, V=Ax,

(2) (/>(/) = ^/, F=^[-r/+^y^],

[2X^t 2X^ ~\

[,3 -5

■*• + zh f T - ?hi' fy

+ 2'K^'J\ J '

(5) <^(0 = At-K V= At~^ [r - ^^ ^ + ^ -^

3-5 x^ 1

~ 2^¥ 71 +•••]'

f— 3 2 ^T) ~l

(6) <l>{t) = ^."'. F= Ae^" |^.r -H ^ ^', + ^,, ^', + • • • J .

r « • S-1-'

(7) <^[t) = /i sin (;//), V= A\ sin (;//).r -|- ^ cos (///) ^ ,

-^2Sin(«/)^, J,

191 1.] LINEAR DIFFERENTIAL EQUATIONS. 283

(8) <i>{t) = ^ log /, V=A ^v log / + -^

3

I x'

+

Y 7 ! J

K-t^ 5 ! ^ K^i
It will be noticed that in this set of solutions [' = 0 when .r^o.

Let u^^f^(xj), U2 = f2{y>^)> ^h = fz{^>^) represent solutions
of the three one-dimensional Fourier's equations,

dV _ d-V (^V _ d^-V dV d'V

~dt^^d7^' a7^ ^' "a7~ a^

respectively. It is readily proved that

y=zn^u.-. and l^ -^ u-^\i.,u,
are solutions respectively of the two-dimensional Fourier's equation

dV (d-V d-V\

and the three-dimensional Fourier's equation

dV (d'V d^V d''V\

~df ^ ^\~dx^ ~^ ~dy '^ ~dz' )'

This shows how solutions of the two- and three-dimensional
Fourier's equations can be obtained from the solutions of the one-
dimensional equation.

For example, from the one-dimensional solutions

Ae'

4Kt

V= -j^-r- and F= Ae''''-'" sin (nx)
the three-dimensional solutions
Ae~^*

(2) F= /^^-(«-+P=+Y-)*''< sin {ax) sin {Qy) sin (7^),

respectively, are obtained.

284 LAMBERT— ON THE SOLUTION OF [April 20.

If the solution of the three-dimensional Fourier's equation
dF „( d-V d'V d^F

/ a-F d'F d'F\

dt

is a function of ;• and / only, so that

F = f{r, t) , where r = (.r- -f y- -\- c- ) *,

the transformation of the given equation from rectangular to polar
coordinates shows that the solution is

r
where u is a solution of the Fourier's equation

du d'^ti

It follows that solutions of the three-dimensional equation of the
form F = f(r, t) are obtained by replacing .r by r in any solution
of the one-dimensional equation

aF _ dht

and dividing the result by r.

In this manner are obtained the solutions

V(i) F=4.

(2) F=^— --

(3) F = — e"' sin (;/;- -|- 2irKt).

It is interesting to compare the solutions of Fourier's partial dif-
ferential equation obtained in this paper with the solutions tabulated
by Sir William Thomson in the mathematcal appendix of the article
on "Heat" in the "Encyclopaedia Britannica," ninth edition.

Sir William Thomson obtains his results bv summation, that is

191 1.] LINEAR DIFFERENTIAL EQUATIONS. 285

by integration, from the solution IV (i) above. All his results
occur directly in the above tables or are combinations of two of these
solutions. It is evident that there are several misprints in the results
as printed in the " Britannica."

Of course there are many solutions of Fourier's equation which
must be built up from elementary solutions, however found, by
means of Fourier series, or which must be obtained by the methods
of harmonic analysis.

The solution III (5) above is the series used by Sir William
Thomson in his solution of the problem of the secular cooling of the
earth.^

An interesting result in pure mathematics is obtained as follows :
Sir William Thomson shows that for a continued point source of
heat, if the rate is an arbitrary function of the time, f(t), the solu-
tion of Fourier's equation when K = i is given by the definite
integral

V

= CdxAt-x)

Jo

bTT'-X"-

The second part of the general solution (B) above shows that

is also the solution of Fourier's equation for the same conditions.
It follows that

/»« fix I r I r f^ "I

i ''-/(' - -) 8^1 = 4^ [7 /W +^'« TT. + /"(') 4 !- + • ■ ■ J
is a general formula for computing the definite integral.

Lehigh University,
Bethlehem, Pa.

* " Mathematical and Physical Papers," Vol. III.

PROBLEMS IX PETROLOGY.

Bv JOSEPH P. IDDINGS.
{Read April 21, 1911.)

The development of the science of petrology from that condition
of the study of rocks, properly termed petrography, is characterized
by the shifting of the emphasis from the purely observational and
descriptive phases of the work to those that relate to the origin and
formation of rocks, both with respect to their occurrence as integral
parts of the earth, and to their composition and structi^re.

Not that there is less need than formerly for accurate observation
and study of rocks, and for thorough description of their composi-
tion, texture and occurrence, but the introduction of greater definite-
ness into conceptions of their modes of formation, and the widening
of the horizon of this field of research through the experimental
and synthetic investigations of the geophysicist, have advanced the
study of rocks from the accumulation of data and statistics, to the
formation of laws and relationships, both as regards minutest details
of composition and texture, and with respect to petrographical prov-
inces, and their connection with the dynamical history of the regions
of the earth in which they occur.

As a consequence of this advance new problems present them-
selves, and invite the cooperation of workers in several branches
of inorganic science. Leaving out of consideration for the present
the great problems of metamorphism, some of which are being suc-
cessfully treated by Adams, or have been under investigation by
Van Hise and Leith, I wish to call your attention to certain phases
of the study of igneous rocks that may be grouped under three
heads for present purposes, as follows : ( 1 ) Tlie actual mineral
composition of igneous rocks, (2) the mathematics of the petrology
of igneous rocks, and (3) petrographical provinces.

286

I91I.] IDDINGS— PROBLEMS IX PETROLOGY. 287

I. Actual Mineral Composition of Igneous Rocks.

Although the minerals constituting various rocks are their most
obvious features, aside from their general color and texture, and
have been the chief object of study by petrographers since the intro-
duction of microscopical methods of investigation, they still remain
among the most important problems before the petrologist.

The exact composition, crystal characters and optical properties
of many of the minerals are well known. But some of the common-
est, such as the micas, amphiboles and aluminous pyroxenes, are not
perfectly understood chemically, and the relation between their com-
position and optical constants is not so definite that one may be
employed to determine the other, as is the case with the lime-soda-
feldspars.

Moreover, the exact amounts of the component minerals in
various kinds of igneous rocks have not been determined, except
in a very few instances ; nor has the precise composition of those
minerals that occur in mixed crystals, that is, the principal ferro-
magnesian minerals, been determined in the vast majority of the
rocks described.

There is, therefore, a great field of research, imperfectly culti-
vated, capable of yielding immediate returns of the first importance
for the solution of other problems connected with the mineral com-
position of these rocks.

Similarly, more definite and specific study and description are
needed of the cr}-stal forms and arrangements of the mineral con-
stituents of igneous rocks than have heretofore appeared in petrog-
raphy, in order that the texture of various rocks may be clearly-
understood, since texture is a very definite exponent of physical
conditions that attended the crystallization of each igneous magma.
Up to the present time petrographers have been content with very
vague and incomplete descriptions of rock textures, as well as of
kinds and amounts of minerals composing various igneous rocks.

The determination of the kinds and amounts of the minerals in
every rock leads to the problem of the formation of the minerals
in each instance, and a comparison of the mineral composition of
a rock with the chemical composition of the magma from which it

288 IDDINGS— PROBLEMS IN PETROLOGY. [April 21,

solidified. This involves the chemistry of solutions of inorganic
compounds, chjefly silicates ; the mutual interaction of the various
chemical elements that appear in an analysis of the whole rock;
together with the possible catalytic action of constituents, notably
water gas, that may not become parts of the fixed compounds, but
may escape in greater part upon the solidification of the magma.

Some of the minor problems, or factors, within this large one
may be alluded to briefly as follows : The first and most obvious
result of a strict correlation of the mineral composition of rocks
with the chemical composition of the whole mass, representing
the fixed components of the formerly liquid magma, is the recog-
nition of the nonappearance in certain kinds of rocks of some
minerals whose presence is necessary to satisfy the chemical require-
ments of the magma solutions. This is the case with completely
crystallized but exceedingly fine-grained lavas of particular com-
positions, notably andesites.

Minerals that should be present to the extent of as much as 30
per cent, in some instances are not visible, are occult, and must

TABLE L

SiO:

59.87

quartz

2.
13.02

18.29

AI.O3

15.02

orthoclase

17.24

9.46

Fe.Os

2.58

albite

28.56

24.63

FeO

340

anorthite

17.28

14.18

MgO

4.06

diopside

3-99

CaO

47y

hypersthene

II. II

Na=0

3-39

hornblende

15-39

K3O

2.93

biotite

14-38

H^G

1.86

hematite

1. 12

TiO.

0.72

magnetite

371

P.O.,

0.26

ilmenite

1-37

F

0.02

apatite

0.50

0.50

Etc.

1. 10

water

I-5I

0.84

1. 00.00

Etc.

1.26

1.26

99.51 100.05

be hidden within the substance of those minerals that are visible :
that is, they must be held in solid solution within other kinds of
crystals. An example will illustrate the case.

A magma whose chemical composition is shown by analysis I,

191 1.] IDDINGS— PROBLEMS IX PETROLOGY. 289

Table I., under favorable conditions should form the mineral com-
pounds in the proportions shown in column 2. In this there are 13
per cent, of quartz, and 17 per cent, of orthoclase, together making
30 per cent, of the whole. And this amount of quartz is the least
amount of free silica capable of separating from a solution of such
a chemical composition, assuming that the minerals formed are those
known to occur in igneous rocks. A magma of this chemical com-
position commonly crystallizes as a pyroxene-andesite composed, so
far as the microscope can determine, of lime-soda-feldspar, pyrox-
ene, and magnetite, with no visible quartz or orthoclase. And, yet,
from the chemical analysis of the rock there should be 30 per cent,
of these compounds.

The orthoclase molecules may be readily imagined in solid solu-
tions within the lime-soda-feldspars, although in coarsely crystal-
lized forms of such a magma, diorite, orthoclase crystals appear as
independent individuals. It has been shown in the Geophysical
Laboratory of the Carnegie Institution, that orthoclase and anor-
thite molecules form homogeneous mixed crystals when melted
together and cooled in an open crucible. The disappearance of 17
per cent, of orthoclase in this particular andesite is, therefore, due
to the conditions of solidification of the rock. The non-appearance
of the quartz may be explained in part by its existence in solid solu-
tion in other minerals of which, however, we have not sufficient
evidence at present ; or it may occur in minute crystals mistaken for
andesine feldspar, since the optical properties of the two that may be
recognized in minute crystals, are almost identical. In coarser
grained forms of chemically similar magmas the quartz appears, but
the conditions attending crystallization in the contrasted cases may
favor its disappearance through solid solution in one instance, and
its separation as quartz crystals in the other.

In this connection it is to be pointed out that the apparent actual
mineral composition of certain igneous rocks may not be the real
mineral composition by as much as 30 per cent, of the whole. For
the occult minerals in solid solution are as much a part of the rock
as though visible. Moreover, the percentages assigned to the min-
erals that are seen must be in error by the amounts of the occult

290 IDDINGS— PROBLEMS IN PETROLOGY. [April 21,

minerals in solution. The problem of the determination of the
mineral composition of rocks is for this reason more complex than
at first appears, and is further complicated by the difficulty of
determining the amounts of colored and colorless crystals, when
they appreciably overlap one another in thin section.

Another obvious result of a comparison of the actual mineral
composition of igneous rocks with the chemical composition of
their magmas is the notable variability in the combination of minerals
that may in some instances result from the crystallization of mag-
mas of like chemical composition. This is true both as to kinds and
amounts of the resulting minerals. A striking illustration of this
variability is found in the mineral composition of three rocks from
the same region, the parish of Gran. Norway, which have been
described by Brogger. Analyses of the three are shown in columns
I, 2 and 3, Table II. The first rock is an essexite, the second a
camptonite, the third a hornblendite, and while the compositions
dififer slightly in percentages of silica, and to a less extent in other
constituents, the chemical resemblances are striking, and the three
analyses lie within the range of many well-known series of analyses
of particular rocks.

TABLE IL

SiO.

I.
4365

40.60

3-

37-90

4-
42.35

orthoclase

T.2

6.

6.1

A1203

11.48

12.55

1317

12.29

albite

Z7

Fe.Oa

6.32

547

8.83

3.89

anorthite

18.9

18.3

FeO

8.00

9.52

8.37

705

leucite

3-9

MgO

7.92

8.96

9- 50

13.09

nephelite

II. I

10.2

CaO

14.00

10.80

10.75

12.49

diopside

26.9

30.2

Na=0

2.28

2.54

2.35

2.74

olivine

8.0

17.9

K,0

1-51

1. 19

2.12

1.04

magnetite

11.6

5.6

H=0

1. 00

2.28

1.40

1.82

ilmenite

10.2

3-5

C0=

tr

2.68

etc

0.62

hematite

0.8

TiO,

4.00

4.20

5-30

1.82

apatite

2.2

P=05

tr

tr

■99

H.O

1-4

1.8

100.16

100.79

99.69

100.19

Etc.

lOO.O

0.3
99.8

The first rock consists of lime-soda-feldspar and augite, with
some olivine and mica, and rarely a little hornblende. The second
rock consists of feldspar and hornblende in nearly equal proportions ;

I9I1.] IDDINGS— PROBLEMS IN PETROLOGY. 291

while the third is ahiiost wholly hornblende, only 2 per cent, being
pyroxene and nephelite. The same magma might have crystallized
as nephelite-basanite, as appears from the calculated mineral com-
position shown in column 5, and from comparison with the analysis
and mineral composition of a nephelite-basanite from Colfax County,
N. M., shown in columns 4 and 6.

This is only an extreme case of variations well known to exist in
most groups of rocks that ma}- be referred to chemically similar
magmas. And the magma alrcad}- cited as capable of furnishing a
pyroxene-andesite may also yield a quartz-mica-diorite, whose com-
position is shown in column 3 of the first table.

It is evident from these examples that the minerals called horn-
blende, or more properly amphibole, in the descriptions of these
rocks differ widely in chemical composition, and often represent
totally different mixed salts. Thus in the hornblendite of Gran, the
hornblende contains all the components that might, under other con-
ditions, have crystallized as pyroxene, olivine, feldspar, leucite,
nephelite and magnetite.

Any attempt to correlate igneous rocks on the basis of the actual
mineral composition, without taking into account the actual chem-
ical composition of the minerals involved in each case must lead to
confusion.

One of the most important problems in petrology is the elucida-
tion of the laws controlling the production of mineral compounds
from molten magmas. A consideration of the simpler chemical reac-
tions that may be expected to take place in silicate solutions like
rock magmas, and which do take place in crucibles in the laboratory,
explains the formation of the feldspars, leucite, nephelite, quartz,
diopside, hypersthene, olivine, magnetite and some other rock
minerals.

Minerals like mica clearly involve the chemical action of water,
or its components, hydrogen and hydroxyl. since hydrogen enters
into its constitution. According to Penfield hydroxyl, and sometimes
fluorine, enters into the composition of hornblendes, forming bivalent
radicles with aluminium, and ferric iron. In pyrogenetic analcite,
and in other possibly primary zeolites in igneous rocks, H^O enters

PROC. AMER. PHIL. SOC. L. I99 S, PRINTED JUNE 30, I9II.

292 IDDINGS— PROBLEMS IN PETROLOGY. [April 21,

into the silicate compound. The physical conditions which control
the chemical equilibrium within magma solutions that yield these
mineral compounds are problems for the geophysicist, though their
nature may be inferred in a general way from the mode of occur-
rence of the rocks containing the minerals in question.

Indications of a catalytic action of H^O within rock magmas are
furnished by the association of free silica with orthosilicates con-
taining magnesium and iron, such as the common occurrence of
quartz and biotite in granitic rocks ; the frequent association of
quartz and tridymite with olivine in lavas ; and of quartz, tridymite
and fayalite in lithophysae in certain highly siliceous lavas.

The instability of these systems under changed conditions of
equilibrium is shown by the inversion of hornblende to an aggrega-
tion of pyroxene, magnetite and feldspar, in some lavas ; and by the
solution of quartz phenocrysts in some basalts, accompanied by the
formation of shells of metasilicates surrounding them.

Already laboratory research has established the range of stability
of some of the rock minerals under laboratory conditions : the inver-
sion temperatures under atmospheric pressures of the various forms
of SiOo, quartz, tridymite, crystobalite ; of the simpler compounds
crystallizing as orthorhombic and monoclinic pyroxene, and the
corresponding amphiboles ; of a simple system involving aluminium,
magnesium calcium silicates ; and of other series of compounds.
The value of these definite contributions to the problems of the
mineral composition of igneous rocks is great. Much more is
needed. And the necessity for eventually approaching nearer to
the physical conditions obtaining in rock magmas is apparent, when
the probable efficiency, chemical and physical, of highly heated
gases under strong pressures is taken into consideration. Research
under such conditions is attended with great difiiculties, and some
risks. Enough has been mentioned to show a wide range for future
study by the geophysicist, the chemist, and the petrographer.

2. The Mathematics of the Petrology of Igneous Rocks.
The study of igneous rocks involves the consideration of groups
of intricate relationships, the exact expression of which is at pres-

igii-l IDDINGS— PROBLEMS IN PETROLOGY. 293

ent beyond our competence. Abstract conceptions of some of the
simpler relationships, based on partial knowledge of the factors
involved, serve to point the way along which quantitative investiga-
tion may be profitably pursued.

The stoichiometric character of the chemical compounds that con-
stitute rock minerals relates them as definite functions to the chemical
constituents of the liquid magma from which they crystallized. The
existence of mixed crystals, and of solid solutions, introduces the
treatment of series into the problem of the expression of the relation-
ship between the mineral composition of a rock and the chemical
composition of its magma. In such an expression the fixed compo-
nents alone are involved. But there are definite quantitative rela-
tionships to be expressed regarding those chemical components of a
magma which may act only catalytically in producing the actual
mineral combination constituting the rock. Such actions may be
chemical, in the sense that compounds form that subsequently dis-
appear, as should H.O combine with SiOo to form hydrogen ortho-
silicate, 1^48104, and subsequently resolve itself into water and quartz
or tridymite. Or they may be physical, in the sense that increased
molecular mobility in the magma liquid may affect the character of
the crystallization by changing the freezing point and the nature of
the compounds stable under the conditions obtaining at the time. In
the broadest sense, then, the mineral composition of an igneous rock
is a function of the chemical composition of the magma.

Since the physical conditions attending the solidification of rock
magmas affect the chemical equilibrium of the constituents, as well
as the physical character of the liquid, its temperature and viscosity,
and also influence the chemical composition with respect to the gas-
eous components capable of being held in solution under pressure,
the mineral composition of an igneous rock is also a function of the
physical conditions attending its solidification.

To a notable extent is this also true of the texture of such rocks,
their degree of crystallization, size of grain, and the shape and
arrangement of the individual minerals. In the expression of these
relationships the treatment of serial functions must be a pronounced
feature. The gradual variations of temperature and pressure are as

294 IDDINGS— PROBLEMS IN PETROLOGY. [April 21,

essential factors in the consideration of the physical conditions of
rock magmas, as the variations in texture and in mineral composition
are universally characteristic features of igneous rocks.

The existence of definite quantitative relations between the min-
eral composition and the texture of igneous rocks on the one hand,
and the chemical composition of the magma and the physical condi-
tions attending its eruption and solidification on the other, rests on
the obedience of the component elements to the laws of physical
chemistry. These laws are not fully established, or known, at this
time, and the relationships involved may be too intricate to be com-
pletely expressed in customary mathematical terms, nevertheless, the
definiteness of the quantitative relationships can not be doubted, and
approximate expressions of them become problems for petrologists
of the future.

In tlie consideration and correlation of all known igneous rocks,
variability in composition and texture and the existence of continuous
series are the most conspicuous general characteristics. The varia-
bility in the composition of igneous rocks indicates heterogeneity in
magma solutions. This mav be inherent in them, and represent a
condition of existence before the initiation of eruption ; or, as is
more probably the case, it may result from difi^erentiation of homo-
geneous magmas during periods of eruptive activity, within more or
less extended regions. Dift'erentiation results from difl^usion of com-
pounds in solid molecules, or less complex ones, either at the time of
separation as cr} stals, or earlier, through convection currents, differ-
ences in density, or dift"erences in solution pressure. The resulting
magma solutions differ only in the quantities of various chemical
compounds : the amount of some in extreme instances reaching zero.
Subsequently formed compounds are not inherently different from
those in other magmas except by reason of the amounts of certain
chemical components, which may be concentrated in some differ-
entiated parts ; as in the concentration of the rare elements in some
pegmatites; or by different combination of chemical elements through
catalytic agents. There are no inherent, or inherited, characteristics
of form, organism, or immaterial traits, as in living beings. The
magmas are simply dift'erently mixed solutions of inorganic com-
pounds.

19".] IDDINGS— PROBLEMS IN PETROLOGY. 295

Magma solutions possess different degrees of heterogeneity as
shown by the composition of various bodies of igneous rocks. In
some there are shght differences in different parts, extending through
large masses. In others marked diff'erences occur within short dis-
tances in small masses. Variability in the composition of igneovis
rocks from place to place is a universal characteristic, resulting in
series of varieties of composition within single bodies, and among
different masses. The aggregate of all such series of variations in
one region may form a continuous series of wide extent; or there
may be gaps in the series in one region, which may be filled by the
phases of composition exhibited by rocks in another region.

In one region the composition of a nearly homogeneous rock mass
of considerable magnitude may assume a certain local petrographic
importance, while in another region it may appear only as a facies
of another rock body. There appears to be no chemicophysical rea-
son for the production of a magma solution of one mixed composition
rather than of another very nearly the same. But it is known that:
magmas of intermediate, or more mixed, compositions, are more
abundant than those of extreme, or simpler, compositions.

The accumulated evidence of chemical analysis, microscopical
study of rock sections, and observation in the field, shows the exist-
ence of wide serial variations of composition, continuous along
numerous lines, owing to the number of variable components. This
evidence also shows that there is no one definitely composed magma
solution more abundant throughout large areas of the earth than
others ; none that deserves special consideration, or may be recog-
nized as a universal type. It is true, as already remarked, that in
certain regions there are large bodies of rock having nearly uniform
composition that assume local importance, and serve as types for
reference in particular regions. But it must be admitted that the
idea of type is subjective, inherent in the petrographer, not the rock.
And when all known series of igneous rocks are treated as products
of chemicophysical reactions universal in their application, the for-
tuitous character of the chemical composition of particular bodies of
erupted magma becomes apparent, and the significance of such local
types disappears in a systematic treatment of the whole body of

296 IDDINGS— PROBLEMS IN PETROLOGY. [April 21,

petrographical facts involved in a comprehensive description of
igneous rocks.

Recognizing the existence of continuous series of petrographical
factors, chemical, mineral and textural, necessary to the complete
description and definition of igneous rocks, the problem presents itself
of dividing the complex series of rocks so characterized into parts
that may be described in a comprehensive and systematic manner.

A familiar example of a physical series divided in a regular man-
ner for purposes of exact use is that of temperature, partitioned in
degrees of definite proportions of a continuous scale. It is undoubt-
edly an arbitrary method and differs distinctly in three commonly
employed usages. It might be a more "natural" method to express
temperature with reference to the melting points of a series of sub-
stances ; and the value of certain of these definite points as datum
points is well known. But the merits of the arbitrarily, but very
naturally, divided scale are attested by its universal employment.

The proposal to partition the petrographical series into quantita-
tively definite parts, as has been done in the Quantitative System of
Classification of Igneous Rocks, the size of the divisions being arbi-
trarily chosen, has excited criticism by some petrographers, who
consider. it arbitrary, artificial and not " natural." But the objection,
that measured precision condemns a classification of igneous rocks,
because it makes evident " its aloofness from the scheme of nature
based not on arithmetical but on physical and chemical principles,"^
suggests a lack of appreciation of the mathematical precision of
stoichiometric chemistry, and a failure to grasp the definiteness of
quantitative physics, whose natural expression is found in higher
mathematics. Both of these sciences are fundamental to that of
petrologv ; and as mathematics is the language, or expression, of
quantitative relationships, the more definite the knowledge of the
quantitative factors and relationships obtaining in igneous rocks, the
more natural will become their expression in mathematical terms.

Acknowledging the usefulness of such terms as " consanguinity "
and " parent " magmas, in emphasizing the fact that there is relation-
ship between rocks in certain instances, it must be admitted that the
too frequent use of these and other biological terms, as " families "
' Harker, A., " The Natural History of Igneous Rocks," 1909, p. 366.

I9I1.] IDDINGS— PROBLEMS IN PETROLOGY. 297

of rocks, minerals of " first and second generation," and the like,
tends to convey by implication the idea that there exists among
igneous rocks genetic relationships analogous to those sustained by
living organisms. In fact, this idea has been clearly formulated
by Marker- in stating that the mutual relationships of igneous rocks
will furnish a " fundamental principle analogous with that of descent,
which lies at the root of natural classification in the organic world."
The significance of the term " natural " when applied by some
petrographers to petrographic classification appears to be pregnant
with biological conceptions. But what is proper and natural in the
treatment of assemblages of organisms is not for that reason, neces-
sarily, proper, or natural, in the treatment of a series of chemical
solutions and their solidified phases, however much the various solu-
tions may be related to one another by reason of differential dififusion
or fractional crystallization.

3. Petrographical Provinces.

Although the fact has been recognized for twenty-five years that
there are regions within which the rocks erupted during any par-
ticular period exhibit certain peculiarities of mineral composition and
texture that distinguish them from rocks belonging to the same gen-
eral group, erupted simultaneously in other regions,' little or no
attempt has been made to define more precisely what constitutes the
characteristics of any so-called petrographical province.

It has been pointed out that in some regions many of the igneous
rocks are especially rich in alkalies ; in some sodium being promi-
nent ; in others potassium. But nothing approaching completeness
of definition, either as to composition of the rocks, or extent and
limit of the region of occurrence, has ever been attempted.

And yet some very general and far-reaching speculations have
been indulged in on the basis of hastily formed impressions, both as
to the character of such groups of rocks and their relationship to
assumed structural features of the earth. As a result certain petrog-
raphers have grouped all igneous rocks into two contrasted cate-

'Ibid., p. 362.

^Judd, J. W., Quar. Jour. Geol. Society, London, 1886, Vol. 42, p. 54.

298 IDDINGS— PROBLEMS IN PETROLOGY. [April 21,

gories, without considering the probability of their being many phases
of combination of the variable factors of igneous rocks that must
characterize all petrographical provinces of the earth.

The assumption that rocks must either belong to what have been
called the "Atlantic " or the " Pacific " provinces, without serious
definition of either of these rather comprehensive terms, has led to
the humorous conclusion that the igneous rocks of Great Britain
belonged in some periods of geological history to the "Atlantic," in
others to the " Pacific "' provinces ; indicating the flexible, one might
say caoutchouc-like, nature of these provinces.

The igneous rocks of the Andes and of the western Cordillera
of North America have been referred to as representing the "Pacific"
province, while the more alkalic rocks of Scandinavia and of some
other parts of Europe are considered to represent the "Atlantic."
The igneous rocks of Great Britain belong to neither of these dis-
tinctive groups as a whole. And the rocks erupted at diflferent
geological periods in Great Britain, while they exhibit some varia-
tions in extremes of composition, which might result from different
degrees of differentiation of chemically similar magmas, bear some
of those resemblances to one another that are supposed to charac-
terize rocks of one petrographical province.

The misconception underlying the generalization responsible for
the terms "Atlantic " and " Pacific," as applied to petrographical
provinces, appears from the facts brought out by Cross regarding the
alkalic character of some of the lavas of Hawaii, and by Lacroix
regarding alkalic rocks in Tahiti ; to say nothing of similar rocks in
Xew Zealand and elsewhere in the southern Pacific. Moreover, in
the midst of Europe, in Hungary, there are groups of rocks identical
in all respects with those of the Great Basin in western America.

From this it is evident that one of the most important and inter-
esting problems before petrologists is the investigation and exact
definition of the districts and regions of igneous rocks in all parts of
the world, with the purpose of obtaining the data with which to form
definite conceptions of what have been termed petrographical prov-
inces. Enough is known already to make it evident that there are
many kinds of such groups of igneous eruptions and not two strongly
contrasted series ; that they blend into one another in composition ;

191 1.] IDDINGS— PROBLEMS IN PETROLOGY. 299

that the dehmitation of the regions, or provinces, may be pronounced
in some instances, and ill-defined in others.

The character of the rocks in different provinces, and the distri-
bution of provinces throughout the earth, together with their rela-
tions to the geological structure and dynamical history of the region
in which they occur, furnish problems of the first magnitude in
petrology.

One of the questions to be answered is : the relation of the com-
position of igneous rocks of dififerent parts of the earth to its isostasy.
The configuration of the earth's surface demands the presence of
material of dififerent densities beneath the surface. Does this show
itself in the character of the material erupted in dififerent regions.
An answer to this can not be given ofi:'hand. The requirements in
density are relatively so slight when great volumes are concerned,
as pointed out recently by Hayford;* the series of igneous magmas
of any region is so diversified in composition and density ; and the
estimation of their several volumes is so hazardous an undertaking
that a reasonable solution of the problem can only be expected after
the accumulation of a great amount of exact data.

Whether there is any relation between the kinds of magma erupted
in a particular region and the dynamical events wuthin the region is
another problem yet to be solved. Assertions to the effect that there
is a definite relationship have been made, but they are in the nature
of broad generalizations upon questionable premises, producing the
results already discussed in connection with the terms "Atlantic "
and " Pacific."

It is possible that dififerences in the sequence of dynamic events
in various regions, or in one region at various periods of its history,
may be accompanied by differences in the processes and results of
dififerentiation of chemically similar magmas; that is, in series of
erupted rocks, but the existence of such relationships has yet to be
clearly established. For it is also possible that the material of the
earth may be heterogeneous in composition, dififering somewhat from
place to place, and yielding dififerent kinds of magmas in different

* Hayford, J. F.. " The Relations of Isostasy to Geodesy, Geophysics and
Geology," Science, N. S.. Vol. 33, No. 841, 191 1, pp. 199-208.

800 IDDINGS— PROBLEMS IN PETROLOGY. [April 21,

regions, each of which may undergo local differentiation according
to conditions of its eruption. The apparent persistency of the major
features of reHef on the earth's surface and the demands of isostasy
suggest an absence of homogeneity within the material of which it
is composed. The solution of these fundamental problems in geology
must rest on petrological research along the lines here indicated.

Such are some of the more obvious problems of petrology, the
solution of which involves the cooperation of petrographers with the
chemist, the geophysicist and the geologist.

A STUDY OF THE TERTIARY FLORAS OF THE
ATLANTIC AND GULF COASTAL PLAIN.^

By EDWARD W. BERRY.

(Read April si, IQII.)

Introductory.

The observations recorded in the following pages may be said
to represent a preliminary sketch of a small chapter in the study of
the South Atlantic and Gulf Coastal plain undertaken by the United
States Geological Survey in cooperation with the various state sur-
veys under the direction of Dr. T. W. \^aughan.

Neither geologist nor biologist fully appreciates the magnitude,
complexity or uniqueness of the coastal plain of the southeastern
United States. The present coast line, a boundary first recognized
by the aborigines and early explorers and so emphasized by geog-
raphers, is from the standpoint of the student of geologic history a
continually shifting demarcation which does not, nor perhaps never,
marked the seaward limit of the physiographic unit known as the
Coastal Plain Province, for the gently sloping land surface continues
seaward beneath the waves of the present Atlantic and Gulf waters
varying distances up to lOO miles or more and then precipitately de-
scends several thousand feet in a few miles, forming the majestic
escarpment which is regarded as the continental boundary. In the
past the coast line has advanced inland over the present emerged
portion of the coastal plain and receded seaward over the present
submerged margin, many times. At one time the waves of the Gulf
of ]\Iexico broke in southern Illinois, at another they were confined
lOO miles south of the present sites of ]\Iobile and New Orleans,
600 miles to the southward.

On the whole, the history of events in Tertiary times has been a
progressive adding to the land area of the continent, the most im-

^ Published with the permission of the director of the United States
Geological Survey.

301

.'502 BERRY— TERTIARY FLORAS OF THE [Apr.i ^i.

portant elevation being that of the early Miocene which was followed
by a subsidence, which was, however, less in extent than those which
had preceded it.

No part of the coastal plain is so favorably situated for the study
of the floras which preceded the present, extending backward to a
time which marks the first recorded appearance of angiosperms, as
that of the Gulf states. No single part of North America contains
so continuous a series of Tertiary deposits carrying fossil plants.
Here we find abundant floras in the lower and middle stages of the
Eocene, considerable floras in the Oligocene. some in the later Mio-
cene, and rather abundant fossil plants in the Pliocene. The Rocky
Mountain region is rich in Eocene fossil plants and there are some
Miocene floras, but no Oligocene or Pliocene floras are known. The
Pacific coast region likewise furnishes Eocene and Miocene fossil
plants but none of Oligocene age. The fossil floras of the coastal
plain are found in an area where it is possible to attain to some
measure of accuracy in predicating the general character and course
of ocean currents and winds and other physical features of the en-
vironment. On the other hand the western floras just mentioned
grew in areas where vulcanism was great at times ; in areas of great
orogenic activity, where changes in topography were numerous and
elevations of several thousands of feet are recorded ; areas in which
climatic conditions not only varied from place to place, but passed
through a large cycle of secular changes. All these factors greatly
complicate the floral history.

The floras of the southern coastal plain are moreover checked
for the most part by very abundant marine faunas in intercalated
beds, or the plant-liearing beds which represent the coastal swamps
and the shallow water deposition of the old embayment merge
laterally with the contemporaneous limestones or marls which were
forming in more open waters along the coasts to the southward, so
that there is a considerable body of facts bearing on depth, character
of the bottom, and marine temperatures, with which to compare land
temperatures. These criteria have been admirably worked out for
the Florida area by Doctors Dall and Vaughan for the post-Eocene
and their results furnished a reliable datum plane for the deductions
to be derived from the studv of the fossil floras of these times.

191 1.] ATLANTIC AND GULF COASTAL PLAIN. 308

So far as I know I was the first paleobotanist to explore the
south Atlantic and Gulf coastal plain and that exploration has only
just begun. Professors Fontaine and Ward visited the region and
collected a few Cretaceous plants a score of years ago. Professor
Lesquereux a generation and a half ago described a few Eocene
plants collected by Professor Hilgard in Mississippi and by Professor
SafTord in Tennessee, and Doctors Knowlton and Hollick have iden-
tified various small collections made by others in different parts of
this vast area.

With the exception of fragments of the petrified stems of con-
ifers, palms and dicotyledons the plant-remains are in the form of
impressions, mostly of foliage, but with a goodly sprinkling of fruits
and seeds, and in some few cases even flowers are preserved.

While the oscillations of the Gulf area have been numerous they
have been, as I have just mentioned, inconsiderable in amount, only
a few hundred feet at most, and the coastal region has uniformly
been one of slight relief. The various floras show a complete
absence of upland types. This is in striking contrast to the Euro-
pean older Tertiary floras. The only large area of the globe which
has been thoroughly studied, Europe, was far less stable than this
region in Tertiary times and lying much farther toward the pole was
subjected to the rigors of Pleistocene conditions whose influence
never reached our southern states.

The object of the writer's work may be classed under three
heads : ( i ) To determine the correlation of the various Tertiary for-
mations particularly in the upper portion of the Mississippi embay-
ment where marine fossils are largely absent, (2) To obtain data
regarding the physical conditions under which the various floras
flourished, (3) To accumulate biological data regarding the geo-
graphical distribution, specific difl"erentiation and evolution of the
Tertiary floras.

Thus one of the principal phases of the study for the geologist
might be embraced under the term paleoecolog)\ The methods
include a study of the old shore lines of the dift'erent epochs, of the
character of the sediments and their genesis, of the contained
animals and plants, and the alternative climatic and edaphic factor.s
which their grouping may indicate.

304 BERRY— TERTIARY FLORAS OF THE [April 21,

It is the chronologic and ecologic aspects upon which I wish to
dwell in the present connection.

The paleobotanical record of the Atlantic and Gulf coastal plain
furnishes a history which extends back as I have just mentioned
beyond the oldest known angiosperm to a time (Lower Cretaceous)
when the flora was made up almost entirely of tree-ferns, conifers
and those interesting cycadophytes (Cycadcoidca) whose trunks are
sometimes preserved with such marvelous perfection that the out-
lines of the embryos in the ovules can often be made out in detail.
Coming a step nearer my present theme, a step of some millions
of years from the Lower into the Upper Cretaceous we find the first
great modernization of the floras of the world due to the seemingly
sudden evolution of the main types of angiosperms. These upptM*
Cretaceous floras are well represented in the coastal plain from
Marthas Vineyard to Texas. They extended northward to Green-
land and southward to Argentina in South America, and are found
to indicate very different physical conditions from those which
prevail at the present time. I do not intend, however, to dwell upon
the Upper Cretaceous floras in this connection but pass to a con-
sideration of the succeeding Eocene stage of plant evolution. In
this as in subsequent times the chief emphasis will be laid upon that
section known as the embayment or old Mississippi Gulf, although
where the record is more complete in other parts of the coastal plain
I will not hesitate to use it.

Basal Eocene.

The Eocene as defined by Lyell was marked by the dawn of the
recent species of marine mollusca. It is ecjually well marked by the
sudden expansion and evolution of modern types of mammals and
plants after a long antecedent Cretaceous development. The floras
become thoroughly modernized as compared with those which pre-
ceded them, although they are still very different in their general
facies and distribution from those of the present.

In the earliest stage of the Eocene known as the Midway, the
relations of sea and land in the Gulf area differed in only minor par-
ticulars from that of the late Cretaceous. The waters of the Missis-

i9'i-] ATLANTIC AND GULF COASTAL PLAIN. 305

sippi Gulf were, however, deeper. This factor combined with a
much less influx of fresh water from the tributary streams, due in
some measure to the low relief of the land, enabled marine faunas
to reach well toward the head of the gulf. These faunas indicate
subtropical bottom temperatures northward as far as Paducah, Ky.
The known floras are very scanty and unsatisfactory and in the
present state of our knowledge do not merit an extended discussion.

Lower Eocene.

The ^Midway Eocene was succeeded by a long interval during
which a great thickness of deposits was laid down which are col-
lectively known as the Wilcox Group. The character of these sedi-
ments and their faunas show that the gulf was somewhat restricted
and much shallower than in the preceding stage, with true marine
conditions prevalent only in its lower portion. The shores were
low and relatively flat. They were flanked by current- or wave-built
bars and separated from the mainland by shallow inlets or lagoons.
The lower courses of the streams were transformed into shallow
estuaries or broad swamps through which the smaller streams
meandered. The accompanying sketch map ( Fig. i ) shows the rela-
tion of land to water at this time. The shore line along which the
strand flora migrated is approximately indicated, and some of the
localities where fossil plants have been discovered in the littoral
deposits of this age are indicated by stars, while the general move-
ment of the warm ocean currents is indicated by arrows. A mag-
nificent flora is preserved at a large number of localities in the clay
.lenses which were formed in these estuaries and marginal lagoons.
This flora shows a mingling of tropical and subtropical types as far
northward as where the Ohio River now flows into the Mississippi.
It is of unparalleled richness and- preservation and will bear a more
extended analysis.

Among the ferns it contains representatives of the genera Acro-
stichum, Pteris and Lygodinni, none of which appear to be common.
Both feather and fan palms are not uncommon. Conifers are rep-
resented by a single occurrence of a species of Arthrotaxis — a genus
which in the living flora is confined to the coastal swamps of Tas-

306

BERRY— TERTIARY FLORAS OF THE

[April 21,

mania but which is widespread in European Eocene floras. A large
variety of dicotyledonous forms are preserved, representatives of
about two hundred difllerent species of which about one third have
thus far been satisfactorily identified. These include seven or eight
species of leguminous shrubs and trees represented by pods as well
as leaflets — evidently strand plants, as are numerous modern species

Fig. I. Sketch map showing the approximate rehition of land to water
in the Lower Eocene. Stars indicate fossil plant localities, diagonal lining
indicates snbmerged areas.

of Acacia, Ccrsalf^iiiia and Dalbcrgia. Evergreen lauraceous forms
are also abundant, the genera Ciiiiianiotnuin, Lauras, Malapooina,
Persca, Orcodaphnc (Ocotea), etc., being represented by several
species. Figs arc abundant and of several species, embracing both

191 1.] ATLANTIC AND GULF COASTAL PLAIN. 307

the pinnately veined and the pahnately veined types. There are
three or four species of Sapiiidiis — another strand type of the mod-
ern equatorial and subequatorial zones. Other members of the
strand flora include representatives of the genera Conocarpns,
Giietteria, Miinusops, Pcrsoonia, Tcrniiiialia, etc. Leaves of several
species of live oaks (Qiicrciis) are abundant. The collections also
include fruits of the families Anacardiaceae and Umbelliferae, and of
the genus Aristolochia. Curious elements common to Europe are
several species of Banksia. an antipodean genus in the existing flora.
There is a fine species of Ccrcis, a very common Enonymus and at
least two species of Engclhardtia based upon the characteristic
fruits as well as leaves. The latter genus has a single existing
species in Central America and several in Asia, where they range
from India to the East Indies. It is common in the European
Tertiary, but has not previously been known with certainty from
North America. An interesting member of this flora is a large
digitate species of Orcopaiia.v, a modern tropical type, abundant in
Central America.

The flora as a whole contains no strictly temperate elements,
although many of the genera contain modern forms which range for
more or less considerable distances in the temperate zone. Such a
flora could scarcely flourish under existing conditions north of
latitude 29°. In its general facies it is subtropical and a number of
the forms indicate a high percentage of humidity, and well dis-
tributed and abundant seasonal rains, although this latter feature
tends to be obscured by the large number of the inhabitants of the
sandy shores which are preserved while the inland and river bank
dwellers are less fully represented. A majority of the elements in
this Wilcox flora could be duplicated today on the Florida Keys and
the southern peninsular mainland of Florida.

Additional members of this flora not enumerated in the preceding
paragraphs include representatives of the genera Apocynophyllum,
Calamopsis, Ccanothns, Celastnis, Ccltis, Cordia, Diospyros, Dryo-
phyllum, Magnolia, Malpighiastrnm, Ncrium, Rhamnus, Rhus,
Sabal, Sapotacites, etc., nearly all of which are new to science.

PROC. AMER. PHH.. SOC. L. I99 T, PRINTED JUNE 30, I9II.

308

BERRY— TERTIARY FLORAS OF THE
Middle Eocene.

[April 21.

Middle Eocene floras are less abundant than those of the Lower
Eocene since this period is marked by a considerable subsidence and
deeper waters in the Mississippi Gulf, which, however, eventually

Fig. 2. Sketch map showing the approximate rehition of land to water
in the Middle Eocene. Stars indicate fossil plant localities, diagonal lining
indicates submerged areas.

became shallower again and duplicated in a measure the Lower
Eocene conditions.

At a number of localities in Georgia and at two or three in north-
ern Mississippi and in Arkansas representatives of the Middle
Eocene flora have been collected. In Georgia where the plants are
associated with shallow water and estuarine invertebrates I found

I9II.] ATLANTIC AND GULF COASTAL PLAIN. 309

the remains of a typical mangrove flora associated with types which
today characterize the tropical and subtropical beach jungle. This
flora includes an Acrostichum closely allied to the modern Acro-
stichnm aureum Linne which is such an abundant fern in the man-
grove and nipa tidal swamps. Other genera represented by fossil
forms are Conocarpus, Dodoiicra, Ficus, Malapanna, Pisonia,
Momisia, Rhizophora, Sapindus, TcrminaUa, and palms of the genus
Thrinax. Botanists familiar with the flora of the torrid zone will
recognize at once that this is a typical strand flora of the tropics
which might almost have been taken bodily from Schimper's classic
Indomalayan Strand Flora, or which can be seen today along the
Florida Keys and in the West Indies.

The plants of this age from ^Mississippi and Arkansas do not
indicate such a well marked ecological group nor quite such high
temperatures as those from Georgia, nevertheless they also are
largely subtropical coastal types and embrace species of Sabal,
Rhamnus, Panax, Ficus, Dryandroides, Persea, Sapindus, etc. One
of the most interesting forms abundantly represented in north-
eastern Arkansas is a citraceous form with alate petioles which I
have named Citropliylluni. Additional genera which are present are
Nectandra and the coniferous genus Arthrotaxis.

In Fig. 2 is shown the approximate position of the shore line
along which the mangrove and the tropical beach flora migrated
northward in the path of northerly flowing tropical ocean currents.

L'ppER Eocene.

No upper Eocene floras are known from the coastal plain but
it is believed that future discovery will reveal their presence when
the area where they are likely to occur shall have been examined
in detail.

Lower Oligocene. -

The Lower Oligocene has yielded no plants except petrified
fragments of the wood of palms and dicotyledons. The sediments
are more or less impure marine limestones, and if marginal deposits
with plants were laid down they were subsequently destroyed by
erosion, or have not yet been discovered.

310 BERRY— TERTIARY FLORAS OF THE [April 2.,

Extensive marine faunas indicate even more torrid conditions
than in the preceding epoch, uniformly distributed over this whole
area.

Middle Oligocene.

The Middle Oligocene deposits are those of shallow tropical
waters with a bottom temperature of at least 39° C. (70° F.), marine
toward the east with true reef corals in Georgia, but becoming
brackish or fresh toward the west, by reason of their shallowness
and the increased volume of fresh water from the Oligocene Missis-
sippi and Tennessee rivers and other streams. The flora is scanty
but includes tropical swamp types, the fern genus Acrostichum being
the most abundant form collected.

The accompanying sketch map (Fig. 3) shows in a generalized
way the relation of land and water in the Middle and Upper Oligo-
cene. It is to be noted that the great Mississippi Gulf had been
reduced to a very wide and shallow reentrant.

Upper Oligocene.

Toward the close of the Oligocene a widespread emergence of
the land was inaugurated accompanied by a slight lowering of tem-
peratures. The floras are not abundant but are represented in
western Florida and central Mississippi. They contain very abund-
ant remains of several species of Sahal-Wka palms; the large leaves
of a species of ArtocarpHS or breadfruit; leaves of figs; of the Cin-
namomum or camphor tree; representatives of the genera Acacia,
Btimelia, Diospyros, Pisoma, Cyiniiida. Clcditsia, Nectandra,
Sapotacitcs, Rhanimis. Uluuis, etc. — the latter being the only genus
which is a strictly temperate type in the modern flora, although most
of the genera enumerated have representatives in the warmer parts
of the temperate zone at the present time.

Miocene.

A long interval followed the close of the Oligocene, during which
the coast line of southeastern North America was considerably sea-
ward from its present position, in consequence of which deposits

igii.]

ATLANTIC AND GULF COASTAL PLAIN.

311

Fig. 3. Sketch map showing the relation of land to water in the Middle
and Upper Oligocene. Stars indicate fossil plant localities, diagonal lining
indicates snhmerged areas.

of this age are tmknown. This interval comprises the first half of
the Miocene age and when renewed stthmergence furnishes ns
with a record we find very different conditions from those pre-
viously enumerated. Either because of the diversion of the gulf
stream to the eastward due to the emergence of peninstilar Florida
or as a result of changes in depth off the Hatteras anticline, a cool
inshore current seems to have swept southward along the coast and
through the Suwannee Strait across northern peninsular Florida,
carrying with it a northern marine fauna which replaced the tropical
fauna that had previously occupied this region.

312

BERRY— TERTIARY FLORAS OF THE

[April 21,

The fossil plants of this age are unfortunately rare and are as
yet unknown south of the Maryland-Virginia area. The accom-
panying sketch map (Fig. 4) shows in a generalized way the upper
Miocene conditions after the resubmergence of the area, the maxi-
mum emergence during the lower Miocene being unknown. The

Fig. 4. Sketch map showing the approximate relation of land to water
in the Upper Miocene. Stars indicate fossil plant localities, diagonal lining
indicates submerged areas.

land masses southeast of the mainland are to be noted as well as
the supposed directions of the ocean currents.

The known fossil plants from the Atlantic coast Miocene,
exclusive of diatoms, include the following species from the Mary-
land area near Washington described by HoUick :'-'

^Hollick, Md. Geol. Surv., IMiocene, 1904, pp. 483-486, tf. a-b.

191 i-l ATLANTIC AND GULF COASTAL PLAIN, 313

Querciis Lchinanni Holl.

Ulmus basicordata Holl.

Cccsalpinia ovali folia Holl.

Rhus Millcri Holl.

Pieris scrobiciilata Holl.

Phyllites sp., Holl.
In addition to the above the following have been described from
the same horizon at Richmond, Va., by Berry :^

Sol-L'iiiia foniwsa Heer?

Taxodinni distichitiii iiiioccnu})i Heer.

Salix Racaiia Heer.

Carpiiiits graiidis Unger.

Querciis calvcrtoncnsis Berry.

Rhus Millcri Holl.

Planera Uiigeri Ettings.

Ficiis richiiioiidcnsis Berry.

Plataiiits aceroides Goeppert.

Podogoniiiui? virginianum Berry.

Dalbcrgia calvcrtoncnsis Berry.

Cclastriis Bruckinaiini Al. Br.

Nyssa gracilis Berry.

Fra.viiuis richniondcnsis Berry.
These plants indicate that the coast was low, which explains the
absence of any but the finest terrigenous materials in the shallow
water deposits which constitute the Calvert formation. The flora
from \'irginia indicates the presence of extensive cypress swamps,
the latter type of plant being the most abundant fossil collected and
the other plants identified being for the most part similar in their
physiological demands upon their environment. The flora from
Maryland is the natural counterpart of that from Virginia in con-
taining several typical elements of just the sort of a plant associa-
tion found on sands (inner beaches and more or less stationary
dunes) along the present coasts in the temperate zone.

Regarding age the plants are clearly Middle Miocene according
to European standards. They indicate less conclusively the climatic
^ Berry, Jouni. Gcol, Vol. 17, 1909. pp. 19-30, tf. i-ii.

814 BERRY— TERTIARY FLORAS OE THE [April 21,

conditions which prevailed along the Miocene coast in this latitude.
There is considerable evidence of a scant rainfall, that is to say of
less than 30 inches annually but this may well have been merely a
coastal condition. Indirectly the lack of land derived sediments in
the deposits points to the conclusion that relatively dry conditions
extended over wider areas. The mean annual temperature is diffi-
cult to determine. Several of the closely allied modern plants such
as the existing bald cypress do not extend north of Maryland in the
existing flora, while Ficus does not fruit north of Virginia, which
also marks the northern limit of Plaiicra. However, the Miocene
forms enumerated are all different specifically from the existing
members of their respective genera and the conclusion is reached
that the Calvert flora would grow under the climatic conditions pre-
vailing at the present time between Sandy Hook. X. J., and Cape
Henry, Va., and that the mean annual temperature which they indi-
cate is between 50° and 55° F.

Pliocene.

Pliocene floras have been unknown from Xorth America until
last year when deposits of this age with abundant fossil plants were
discovered in southern Alabama. The most remarkable form in
this flora is the fruit of Tvapa, the water nut, which Raimann in
Engler and Prantl segregates from the family Onagraceas to form
the family Hydrocaryaceas. In the existing flora this genus has only
three species of southern Europe and southeastern Asia but it is
well known in the older Tertiary of Xorth America and Europe
and in the later fossil floras oi Europe. Another interesting species
in this Alabama Pliocene flora is a species of Glyptostrobus, a
coniferous genus allied to our bald cypress which is now confined
to eastern Asia, but which appears to have been cosmopolitan in
Tertiary times. Other elements of this flora are abundant live-oaks
( Qucrcus) ; several species of elm (Ulnms) ; abundant twigs, seeds
and cone scales of a species of cypress which is very close to the
existing bald cypress ( Taxodium). Additional elements are species
of Nyssa, Ilicoria, Plaiicra, Bctula, Dioscorea, Primus, Pinus, etc.
This flora is <]uite modern in its facies and is a mixture of swamp

1911.] ATLANTIC AND GULF COASTAL PLAIN. 315

types and those of live-oak barrens. Among existing localities which
I have visited which impress me as duplicating the climatic and other
physical conditions indicated by this late Pliocene flora are the estu-
aries along the gulf coast of Alabama and western Florida, among
which Apalachicola, Mobile. Perdido and Pensacola bays are the
larger. The Santa Rosa peninsula which separates the latter from
the Gulf of ^lexico supports a flora that is very similar to this
Pliocene flora and one or two of the species represented in both
are closely allied and may even be identical.

Pleistocexe.

Pleistocene plants are also common throughout most of the
coastal plain and when they shall have been thoroughly studied they
will yield a large body of exact facts which will throw much light
upon the immediate ancestry and migrations of our existing flora.
Already more than one hundred species have been recorded, most
of which are still existing and these indicate a very difl^erent geo-
graphical distribution from that of the present coastal plain flora.

COXCLUSIOX.

I have only had time in the foregoing remarks for a very frag-
mentary and incomplete sketch of the present study which has really
only just commenced. With the complete exploration of the area
and the additional collections which it is hoped to make it is believed
that the combined results of the speakers studies of the fossil floras
and those of his associates on the fossil faunas and the areal geol-
ogy will furnish a basis for reconstructing the physical, faunal and
floral history of the southern states, during the several millions of
years from the Cretaceous to the present, which will constitute a
lasting contribution to the history of the earth.

AN OPTICAL PHENOMENON.

' By FRANCIS E. NIPHER.
{Read April 31,1911.)

In 1871 in a letter to Tyndall, Joseph LeConte gave an interest-
ing discussion of an ocular illusion which had been previously
described. Tyndall communicated it to the Philosophical Magazine
(XLL, p. 266). The phenomenon was observed in the manner here
described :

Pierce a card with a pin. Hold it before the eye at a distance
of four to six inches, looking through the hole at a bright back-
ground. Place the pin in front of the eye with the head central
in the pupil and in close proximity. The pin head will be " seen
in the hole," and in an inverted position.

As was pointed out by LeConte, this is not an optical image but
a shadow. As proof of this he cites the fact that if a series ot
holes are made in the card, a similar appearance of the pin head is
seen in each hole. He adopted the idea that objects are seen erect,
because the nerve fibers at the lowest point on the image see the top
of the object in the direction along which those rays have come.
He also argued that the inverted appearance of this shadow, which
was erect on the retina, was in harmony with this explanation.

The well-known fact that this point in the image is the vertex
of a cone of rays, whose base is the pupil of the eye, and that this
diverging bundle of rays, when traced outward, does not define the
position of any external point, is sufficient explanation of the fact
that this line of reasoning has not been generally adopted. Evi-
dently the fact that there are no rays has also been taken into con-
sideration. It does not seem quite evident that nerve fibers at the
lower point of the image on which ether waves collapse and deliver
their impulses could " see " that these waves had their origin at a
definite point, at the top of an object, at a definite distance from the
refracting media, in w'hich the radii of curvature of these waves
were reversed in direction. And these waves from this point on the
object are involved in a summation of waves from other and adjoin-
ing points.

316

ipii.J XIPHER— AN OPTICAL PHENOMENON. 317

Many observers have doubtless had experiences hke those which
the writer had years ago while doing surve}- work. Two transit
instruments were available, one of which showed the object viewed
in erect, and the other in inverted position. A few days of use of
either instrument enables the observer to give proper signals to the
rod-man in a perfectly automatic way. After having thus become
alternately educated, an attempt to use these instruments at random
for brief intervals, relying wholly on what he sees through the instru-
ment for the information which is to guide him in making his sig-
nals, leads to the most helpless confusion. The observer even seeks
to find his way out of his difficulties by comparing what he sees
through the instrument with the impression received by a direct view.

Such experience as this appears to justify the conclusion that we
see external objects as we have learned how to see them, by help of
our other senses. Even then it is a matter of never-ending wonder
that we have in our possession certain nerve-fibers that can be trained
to see.

There are many interesting features of the phenomenon which
LeConte discussed which appear to have escaped his attention. His
claim that the sharp outline of the pin head seen in the hole could
not be an optical image, since such an image would be so much out
of focus as to be invisible, is justified to this extent. The object is
in fact also visible in its real position in shadowy outline. It appears
transparent, and the inverted shadow of the pin head is mentally
projected outward and appears to be visible through the object itself.
Every detail of the letters on a printed page is visible through this
enlarged and transparent appearance which the object itself presents,
due to an out-of-focus image on the retina.

The sharpness of outline of the shadow decreases as the hole is
made greater in area. This is due to penumbral effects. A black
card gives more sharply defined results than a white one. A tube
having the pierced card at one end and the pin head at the other may
be applied to the eye, in such a way as to cut ofl:' all side light. The
head may be covered with a black cloth, which is also wrapped around
the tube. The shadows are then as sharply defined as an optical
image could be. If the black sateen cloth be thrown over the head,
and the eves be directed towards a bright skv, a multitude of cir-

318 NIPHER— AN OPTICAL PHENOMENON. [April 21,

cular images like pin hole images will be seen between the crossed
fibers. Some of these are due to the right eye and some to the left.
A pin head in front of either eye will show multitudes of inverted
pin head shadows.

A circular disk of white paper having a diameter of i mm. or
slightly less, mounted upon a black card will also have upon it a
sharply defined black shadow of the pin head, if the side facing the
observer is illuminated. The paper disk must be near enough to
the eve so that its image on the retina is out of focus, as in other
cases where the pin hole is used. At various points on the glowing
end of a cigar, when observation is made in a darkened room, similar
shadows may be observed. A small blot of ink on a sheet of white
paper will yield a white shadow of the pin head. The same result
is given bv a hole in a white card, if the card is illuminated and
observation is made through the hole at a dark background.

If the reflected image of the full moon or of a bright star from
the convex surface of a lens be used instead of the pin hole in a card,
the inverted shadow will be observed. If the reflecting surface is
concave, the shadow will appear erect if the eye is placed between
the reflector and its principal focus. If the eye and pin are in the
divergent beam beyond the principal focus, the shadow of the pin
head will appear inverted.

It is evident that when the shadow on the retina is erect, it appears
inverted, and I'icc versa.

The eye lens and retina may be replaced by a convex lens and a
paper screen upon which an image of the moon may be cast. A pin
closelv in front of the lens will show no .shadow. If another convex
lens be now placed in front of the lens representing the eye, the
moon's image will be out of focus. The moon's image may be in
front of or behind the screen, according to the position of the second
lens. The shadow of the pin will then appear.

The capacity for accommodation of this artificial eye is unlim-
ited, and the second lens may be dispensed with. The screen being
placed between the lens and the image, the shadow of the pin will
appear erect on the screen. When placed beyond the image, it will
appear inverted.

If an opera glass be focused on a street lamp 50 meters away a

191 1.] NIPHER— AN OPTICAL PHENOMENON. 319

pin head between the eye and the eye-lens will produce no shadow
on the retina. If the glass be ^focused for a nearer object, an erect
shadow will appear. If focused for a more distant object, the
shadow will appear inverted. A hole through a card and with a
bright background may be viewed by means of the opera glass. The
hole may have any diameter from 0.05 to 1.5 cm. The distance of
the card must be adapted to the diameter of the hole, and may vary
from close contact with the object lens to three or four meters, the
glass being focused for a more distant object. The results are as
indicated above. The setting sun surrounded by bright clouds may
be used as an object, if viewed through the foliage of trees thirty or
forty meters distant, the glass being focused for an object more
distant than the trees. The mass of foliage will be dotted with pin
head shadows. Each opening through the leaves acts in a manner
similar to the pin hole.

In all of the cases described, the shadow upon the retina is by
some mental act projected outward in space. An interesting ques-
tion arises concerning its apparent position. LeConte says that in
his experiments it appears in the hole in the card. Perhaps it would
be proper to say that it is seen through the hole. The hole itself
may have a diameter of about one third that of the pin head, and
the pin head then appears smaller than the hole. Its apparent size
depends somewhat on the diameter of the hole.

If a pin is placed back of the card and in erect position so that
it is visible through the hole, it may be so placed that it has the same
apparent size as the shadow. If the pin is at a distance of 30 cm.
from the eye, and the card is at a distance of 15 cm., the shadow
and the pin will have the same apparent size. The appearance of the
inverted shadow and the erect pin is as shown in Fig. i.

(D

Fig. I.

This suggests an interesting device whereby the line of sight of
the tw^o eyes and the capacity for muscular adjustment may be exam-

320 NIPHER— AN OPTICAL PHENOMENON. [Api-ii 21,

ined. Pierce a card with two pin holes, at such a distance from each
other that when placed at half the distance of distinct vision from
the eyes, they may be seen as one. This can be done by drawing lines
across the ruled lines of a page of white paper, and crossing the
ruled lines symmetrically so that at the top of the page the lines are
farther apart and at the bottom they are nearer together than the
two eyes. Pierce pin holes at each intersection of the ruled lines
with the cross lines. If held in front of the eyes so that the cross
lines are seen double, the two inner images of the lines will appear
to cross. At this distance apart thus determined two holes will
appear as one. Place a card having holes thus placed in front of the
eyes. Mount two pins in front of the pupils so that the two shadows
appear superposed in the superposed images of the holes. Two pins
may now be placed back of the card so that when viewed through the
holes they will also appear superposed. The two holes and the four
pins will then present the appearance shown in Fig. i. This ar-
rangement locates two points along the line of sight of each eye.
The holes may be in separate cards which close the ends of two
tubes, through which the observations are made. These tubes,
together with the pins, should be capable of screw adjustments.

When the pin hole is viewed through a tube which is lined with
dark paper, the card serving to close the outer end of the tube, it may
be used for an examination of certain imperfections in the eye. For
exauTple, in my own case one eye shows a minute hole with a bright
background to be of uniform appearance. \'iewed by the other eye
a rather sharply defined shadow is shown in the center of the hole.
This is due to a slight irregularity in the curvature of the outer sur-
face of the cornea. This is due to a grain of gunpowder which was
blown into the eye from a horse-pistol which was discharged from a
distance of about 35 cm., into the lower part of the face, about
fifty years ago. The grain of powder w^as visible for many years,
but has been gradually absorbed. A slight distortion of closely ruled
parallel lines indicates that an irregularity of the surface still per-
sists. The shadow seen in the pin hole shows that light is not uni-
formly spread over the retina when a slightly divergent beam of
light enters the pupil. Any opacity in the crystalline lens would
also produce a shadow upon the retina.

OBITUARY NOTICES OF MEMBERS
DECEASED

lai'nlni^ I kiivicns Van't fldtt.

JACOBUS HENRICUS VAN'T HOFF.

(Read April 22, 1911.)

It is always pleasant to discuss the work of a truly great man,
but the loss of an adored teacher and one of the best of friends, is
among the most trying ordeals through which we are called upon
to pass.

I shall say relatively little of the life of Van't Hofif, since it was
simple and comparatively uneventful ; but devote most of my time to
his work — work which found chemistry, for the most part, an em-
pirical science, and left it well advanced towards becoming an exact
branch of natural science.

Jacobus Henricus Van't Hofif was born in Rotterdam, August 30,
1852, the son of a physician. He died in Berlin, March i, 191 1, and
was, therefore, almost exactly fifty-eight and a half years old. He
received his early training in the " Realschule " in Rotterdam, and
in 1869, at the age of seventeen, went to the Polytechnikum in Delft,
completing the three years' course there in two years. At the age
of nineteen he went to the University of Leyden and remained there
one year. He then repaired to Bonn to work with the distinguished
organic chemist, Kekule, and thence to Paris to come under the
influence of Wiirtz. He then returned to Holland and in 1874, at
the age of twenty-two, made the Doctor's degree at Utrecht, his dis-
sertation being in the field of organic chemistry.

Van't Hofif, in 1876, at the age of twenty-four, was appointed pri-
vatdozent in physics in the veterinary college in Utrecht. He was
called to Amsterdam in 1877 as lecturer in chemistry, and in the
following year was appointed professor of chemistry. Van't Hofif
held the position of professor of chemistry in the University of Am-
sterdam until 1896, when he accepted a call to Berlin as professor
in the University and a member of the Imperial Academy of Sciences.
He lectured once a week on physical chemistry in the University of
Berlin, and a research laboratory was provided for him in the suburbs

iii

iv OBITUARY NOTICES OF MEMBERS DECEASED.

of Berlin by the Imperial Academy of Sciences.

Let us now turn to the work of this very great man.

Van't Hoff's name will always be associated with the following
epoch-making discoveries :

The founder of the science of stereochemistry.

The first to apply the law of mass action to chemical reactions in
a broad way, and thus to open up the fields of chemical dynamics
and equilibrium.

To have pointed out the close relations between solutions and
gases, and thus to have placed the whole subject of solutions upon
a scientific basis.

Van't Hoff, as we have seen, began his scientific career as a pupil
of Mulder in Utrecht, of Kekule in Bonn, and of Wiirtz in Paris.
During this period he was, therefore, busy primarily with organic
chemistry, and let us see the result. At the age of twenty-two, while
still a pupil of Mulder in Utrecht, he published in 1874 a short paper
of eleven pages in Dutch, which was destined to revolutionize the
whole subject of organic chemistry. Organic chemistry, at this time,
under the dominating influence of Kekule was concerned chiefly with
the question of constitution, but the constitutional formulje then in
vogue did not even raise the question as to how the atoms within
the molecules are distributed in three dimensions in space.

The short paper by Van't Hoff in Dutch had to do with the tre-
mendous, and apparently hopeless problem of the arrangement of the
atoms in the molecules in space. The following year (1875) this
paper was translated into French, bearing the title " La Chimie dans
I'Espace," and two years later into German, with a preface by Wisli-
cenus, " Die Lagerung der atome im Raume." Let us glance briefly
at the contents of this paper.

It had been shown by the work of Henri and others that methane,
or marsh gas (CH^), is a symmetrical compound, /. c, all of the
four hydrogen atoms bear the same relation to the carbon atom.
Van't Hoff pointed out that this fact alone forces us to conclude that
methane must be represented in space by the regular tetrahedron ;
the carbon atom being at the center of the tetrahedron and the four
hydrogen atoms at the four solid angles. This is the only geomet-

JACOBUS HENRICUS VAN'T HOFF. v

rical form in three dimensions in space in which a central object is
surrounded symmetrically by four things of the same kind. Thus
arose the conception of the " tetrahedral carbon atom." Pasteur had
been studying the property possessed by certain liquids of rotat'ng the
plane of polarization of a beam of polarized light passed through
them. He had reached the conclusion that in order that a liquid
should have this property — be " optically active "■ — its molecules must
possess some kind of asymmetry. Further than this Pasteur could
not go. The solution of the problem of optical activity remained
for Van't HoiT.

He examined the constitution of all of the optically active com-
pounds of carbon then known, and found that they all contain at
least one carbon atom in combination with four different atoms or
groups : and this applies to every optically active compound of carbon
known today ; and these number more than a thousand. Van't Hoff
simply extended his theory of the " tetrahedral carbon atom " to
that of the "asymmetric tetrahedral carbon atom" and the problem
of optical activity was solved.

This was the beginning of the stereochemistry of carbon, from
which the stereochemistry of several other elements is the outgrowth ;
and it is not an exaggeration to say that the tetrahedral carbon atom
has been the guiding thought in organic chemistry for the past thirty
years.

Shortly after the appearance of the little paper in Dutch Van't
Hoff published his book on organic chemistry "Ansichten iiber die
organische Chemie." In this work he attempted to systematize or-
ganic chemistry, and especially to place it upon a quantitative basis.
He was impressed with the purely qualitative nature of organic
chemistry as exemplified by the Kekule school. Certain substances
were brought together under certain conditions and certain " yields "
were obtained. Very little had been done up to that time towards
measuring the velocity of reactions, or the conditions under which
chemical equilibrium was reached. These were the problems to
which Van't Hoff next turned, and the results of his studies in this
field constitute his second great contribution to chemical science.

It had long been known that mass or relative quantity of the

vi OBITUARY NOTICES OF MEMBERS DECEASED.

reacting substances not only conditions the velocities of chemical
reactions, but often even the direction or nature of the reaction.
The effect of mass on chemical reaction was given simple algebraic
expression in 1867 by the Norwegian mathematical physicist Guld-
berg, and the Norwegian chemist, his son-in-law, Waage ; both of
the University of Christiania.

It remained here again for \*an't Hoff to demonstrate the real
importance of the law of mass action. He showed that chemical
dynamics in general, and the conditions that obtain when chemical
equilibrium is reached, can all be dealt with by the law of mass
action. In this work the whole subject of chemical dynamics and
equilibrium was reduced to a science, and whatever has been subse-
quently done in this field has felt the influence of this early work
by Van't Hoff.

The results, both dieoretical and experimental, obtained by Van't
Hoff and his co-workers, were published in the well-known volume
•^ fitudes de Dynamique chimique " in 1884. In the portion of the
work that deals with chemical dynamics, it is shown that the velocity
of a reaction is a function of the number of molecules taking part
in that reaction ; and a method for determining the " order " of a
reaction, or the number of molecules taking part in the reaction was
worked out. The effect of temperature on reaction velocity was
here discussed, and it was pointed out that chemical reactions are, in
general, much more complex than we are usually accustomed to
regard them ; a number of " disturbing " factors coming into play.

The treatment of chemical equilibrium is quite as important as
that of chemical kinetics. The new feature here was the systematic
application of thermodynamics to such problems. Before this book
appeared there was no scientific treatment of the subject of chemical
equilibrium. Van't Hoff showed in this volume the importance; in-
deed, the absolute necessity of a physical and mathematical training
for every chemist who wishes to go beneath the purely empirical
side of his science.

We come now to the third and greatest contribution of Van't
Hoff to chemistry in particular and to science in general, the rela-
tions betiveen solutions and gases.

JACOBUS HENRICUS VANT HOFF. vii

The first paper dealing with this subject was published in i!
in the Transactions of the Swedish Academy of Sciences, under the
title " The Laws of Chemical Equilibrium in the Dilute Gaseous or
Dissolved State of Matter." This, according to Donnan/ was
quickly followed by two other papers : "A general Property of Dilute
Matter" and "Electrical Conditions of Chemical Equilibrium."

The well-known paper in which the relations between solutions
and gases were first pointed out was published in the first volume of
the Zeitschrift fi'ir physikalische Chcmie, under the title " Die RoUe
des osmotischen Druckes in der Analogic zwischen Losungen und
Gasen," and which has been translated into most of the civilized lan-
guages of the globe.

It is always interesting to learn how a great mind discovers a
great generalization, and in this case we have the account in \'an't
Hoff's own words. He delivered in 1894 his well-known lecture
before the German Chemical Society which led directly to his call
to the University of Berlin. From this the following section is
quoted :

" Jung wie ich war, wollte ich dann audi die Beziehungen zwischen
Constitution und chemischen Eigenschaften kennen lernen. Die
Constitutionsformel soil ja doch schliesslich Ausdruck des ganzen
chemischen A^erhaltens sein.

" So entstanden meine 'Ansichten iiber die organische Chemie,'-
die Sie wohl nicht kennen. Es lohnt sich auch kaum. Nur batten
sie fiir mich den Werth, dass sie eine bestehende Liicke mir sehr
scharf zeigten.

" Nehmen wir ein Beispiel !

"Wie bekannt. iibt in organischen X'erbindungen der Sauerstofl:'
eine beschleunigende Wirkung auf fast sammtliche Umwandlungen
aus: Oxydation bei CH^ schwerer als bei CH3OH u. s. w.

"Um jedoch daraus werthvolle Beziehungen zu erhalten, ist
genaue Kenntniss der Reactionsgeschwindigkeit Beditrfniss, und so
gings zur Reactionsgeschwindigkeit, und es entstanden meine :

"Etudes de dynamiqne chimique.

^Nature, 86, 85.

^ Ber. d. chem. Gcs., 27, 7, 1899.

viii OBITUARY NOTICES OF MEMBERS DECEASED.

" Reactionsgeschwindigkeit zunachst als Hauptzweck. Chem-
isches Gleichgewicht aber iinmittelbar daneben. Wo doch das
Gleichgewicht einerseits auf Gleichheit zweier entgegengesetzter Re-
actionen beruht und anderersits durch sine Verkniipfung mit der
Thermodynamik eine feste Stiitze gewahrt.

" Sie sehen, un mein Zeil zu erreichen, kam ich stets waiter vom
Ziel ; das kommt ofter vor.

"Und weiter musste ich noch, denn die Gleichgewichtsfrage
grenzt unmittelbar an das Affinitatsproblem, und so war ich angelangt
bei der sehr einfachen Affinitatserscheinung, zunachst derjenigen,
welche als Wasseranziehung sich aussert.

" Schon Mitscherlich hatte sich in seinem Lehrbuch der Chemie^
die Frage gestellt nach der Grosse der Anziehung, welche das Krys-
tallwasser im Glaubersalz zuriickhalt. Ein Maass dafiir erblickte
er in der verminderten Krystallwassertension :

" ' Wenn man in die Barometerleerc bei Q° Glaubersalz bringt,
sinkt das Quecksilber um 2.5 Linien (545 mm.) durch W'asserdamp-
fabgabe. Wasser selbst bewirkt dagegen eine Senkung von 4 Linien
(8.72 mm.) — die Afhnitat des Natriumsulfats zu seinem Krystall-
wasser entspricht also der Differenz 1.5 Linien (3.27 mm.) d. i. etwa
1/16 Pfd. (1/32 kg.) pro Ouadratzoll (2.615 qcm.).'

" Dieser Werth, 1/200 Atm., kam mir unerhort klein, hatte ich
doch den Eindruck, dass auch die schwachsten chemischen Krafte
sehr gross sind, wie es mir z. B. auch aus Helmholtz' Faraday-
Lecture hervorzugehcn schien.

" So lag die Frage nahe. ob nicht noch in einfacheren Fallen
diese Wasseranziehung in mehr directer Weise zu messen sei, und
dann ist wohl die wassrige Losung die einfachst denkbare, bedeutend
einfacher als die Krystallwasserbindung.

" Mit dieser Frage auf den Lippen aus dem Laboratorium kom-
mcnd, begegnetc ich dann meinem Collegen de Vries und seiner
Frau ; der war gerade mit osmotischen Versuchen bcschaftigt und
machte mich mit Pfeffer's Bestimmungen bekannt."

Thus was Van't Hoff brought in contact with the measurements
of osmotic pressure made by Pfeffer, and " with that insight into

^4. Auflage, 565, 1844.

JACOBUS HENRICUS VAN'T HOFF. ix

the real meaning of phenomena, and that foresight that enables one
to see relations from very meager and imperfect data, which are
characteristic of the highest genius, \'an't Hofif saw from the few
osmotic pressure measurements of Pfefifer the relations between solu-
tions and gases — the laws of gas pressure applied to the osmotic pres-
sure of solutions. In a word, we could deal with solutions as with
gases."

This raises the question why is it so important to be able to deal
with solutions as with gases? We know more about matter in the
gaseous state than in any other state of aggregation. There we can
apply the laws of thermodynamics. A^an't Hofif applied the law's of
thermodynamics to solutions and gave us for the first time a satis-
factory thermodynamical theory of dilute solutions.

The question, however, still remains, why is a satisfactory, rigid
theory of solutions of such importance? This becomes almost self-
evident if we will consider what solutions mean for science in general.

The whole science of chemistry is hardly more than a branch of
the science of solutions in the broader science of that term. Solu-
tions are fundamental to nearly all of the biological sciences, experi-
mental botany, zoology, physiology, pharmacology and pathology, and
geology is as dependent upon solutions as chemistry.

In the light of these facts it is obvious that the science of solu-
tions is fundamental for natural science in general, and the placing
of solutions upon an exact, scientific basis might almost be regarded
as the initial step tow^ards rendering chemistry, geology and the bio-
logical sciences exact branches of science.

This is what \ an't Hoft' did in pointing out the relations between
solutions and gases. He, however, did not stop here. The laws of
gases apply to the osmotic pressures of solutions of nonelectrolytes
only, /. r., to solutions of substances which do not conduct the cur-
rent. These laws do not apply to the osmotic pressures of a single
electrolyte, and since all acids, bases and salts are electrolytes the
gas laws do not apply to solutions of the most common substances
in chemistry. \"an't Hoff saw clearly these exceptions to the rela-
tions that he had discovered and pointed them out in his great paper
above referred to. It is well known that it was to explain these

X OBITUARY NOTICES OF MEMBERS DECEASED.

exceptions that Arrhenius proposed the Theory of Electrolytic Dis-
sociation.

We must not gather the impression that these three epoch-making
contributions of Van't Hoff to science were the whole of his life-
work. Quite the opposite is true. They were only his greatest
work.

He made a number of other discoveries which would have ren-
dered any less distinguished man famous. Take his paper on " Solid
Solutions" published in volume five of the Zcitschrift filr physika-
lische Chcviie. Before this paper appeared we hardly ever thought
of certain mixtures of solids having the properties of liquid solu-
tions. Van't Hoff showed that such was the case, and thus opened
up a new field of research.

After accepting the call to Berlin Van't Hoff took up an elabo-
rate experimental problem — the study of the formation of the salt
deposits from desiccated inland seas, such as at Stassfurth. He had
previously studied the conditions of formation and decomposition of
double salts, especially the conditions of temperature and concentra-
tion, and published the results in his " Vorlesungen iiber Bildung und
Spaltung von Doppelsalzen " in 1897. The methods which were
developed in this eailier work were applied to this complex geological
problem with great success. The results of this investigation carried
out from 1896 to 1909, partly with Meyerhoffer and partly with
assistants, were published in two volumes, one in 1905 and the other
in 1909, under the title " Zur Bildung der ozeanischen Salzabla-
gerungen."

The writer, only a year and a half ago. heard Van't Hoff express
the wish that this work might all be published in collected form, but
he added that the means were lacking and he never lived to see this
desire gratified.

The total number of papers published by Van't Hoff' was very
small. In addition to the books mentioned above should be added
his " Vorlesungen iiber theoretische und physikalische Chemie," his
"Theory of Solutions" and " Acht Vortriige iiber physikalische
Chemie " being the lectures delivered at the University of Chicago
in 1901.

JACOBUS HENRICUS VAN'T HOFF. xi

A few words in conclusion in reference to \"an't Hoff the man.
The writer was fortunate enough to have worked in the laboratory
of Van't Hoff in Amsterdam in the spring of 1894. His method of
work was somewhat as follows : When interested in a problem he
would gather together all the data bearing upon it, assign what he
considered the proper value to each determination and then as the
result of such comparisons draw his conclusions.

There has been a wide diversity of opinion as to whether \^an't
Hofif was, or was not, a great experimenter. While this is a matter
of very little consequence, because there are many to experiment for
every A'an't Hoff to generalize, this difference in opinion arose I
think as follows : A'an't Hoff published very few experimental results
until he took up the problem of the conditions under which the salt
beds were deposited. This naturally led to the conclusion that he
had done very little experimental work, while such was not the case.
He published very little experimental work not because he did very
little, but because of his attitude towards such w^ork. He did not
publish results simply for their own sake. If they confirmed or
disproved some theory or generalization in which he was interested,
they were published, otherwise not. He looked upon experimental
results as valuable not in themselves, but just as they bore upon
some generalization. During my student days in his laboratory
Van't Hoff" was working very intently and for long hours, but not
a result that he obtained during that period was ever published.
Personally, I regard Van't Hoff' as a very skillful experimenter, but
he looked upon experimental results in a dift'erent way from most
men.

During the time at least that I was with \*an't Hoff' in Amster-
dam, he impressed me as living under an intense strain. His every
motion suggested one keyed to a high pitch. He had wonderful
power of concentration, which reminded one of Rowland. In Berlin
he seemed to have " let down " as we usually say. He \yas living
on a much lower key, probably due in part to the disease which
much too early ended his career.

When I saw him for the last time last summer a year in Berlin,
it was obvious that he was losing in the fight against the disease.

xii OBITUARY NOTICES OF MEMBERS DECEASED.

Although suliering from shortness of breath, the same personal
charm which characterized him in heaUh was still there. He was
one of the most simple, modest, honest, unostentatious and unselfish
of men.

Van't Hoff enjoyed at least one blessing not given to all great
men. He lived to see his work understood, recognized and appre-
ciated. He was a member of most of the learned societies and acad-
emies in the world. He was elected a foreign member of the Amer-
ican Philosophical Society in 1904. He was elected a foreign mem-
ber of the Royal Society in 1897. He received honorary degrees
from a large number of the most distinguished universities, including
Cambridge, Manchester, Heidelberg and Chicago. The German em-
peror conferred upon him the order " Pour le Merite," and Van't Hoflf
received the first Nobel prize in chemistry in 1901. The University
of Berlin at their centenary celebration of 1910 bestowed upon him a
gold medal for his scientific researches (Die grosse golden Medal-
lia zur Wissenschaft). According to recent advices the city of Rot-
terdam will create a \^an't Hoff prize, to be awarded, like the Nobel
Prize in Chemistry, for the best investigations in the field of chemistry.

A leading Berlin journal thus refers to \'an't Hoff: " Ein ganz
Grosser ist dieser Tage gestorben, der Chemiker A an't Hoff." This
can scarcely be translated into English. We have no words strong
enough to convey in good English the exact meaning of " Ein ganz
(irosser."

Prom the same journal I quote: "Van't Hoff' hat uns wie ein
neuer Kopernikus das Weltzystem Weiter begreiben gelehrt; Van't
Hoff, ein geborener Hollander, tatig an der erstcn deutschcn Uni-
versitat, gehorte mit seincm Wissen der ganzen Welt."

The accompanying photograph, which was recently sent me by
Mrs. Van't Hoff, represents the great man as he appeared shortly
before his death.

Thus lived and worked and died not only one of the very greatest
men of science of his day, but of all time ; a man whose name the
history of science will reverence as it does that of Maxwell, Pasteur
and Helmholtz.

Harry C. Jones.

Johns Hopkins University,
April 20, 1911.

^^L^e^^<:^^rr>)^ (^. iy^^

GEORGE FREDERICK BARKER. M.D., Sc.D., LL.D.

(Read May 5, igii.)

When the present writer was asked to prepare a memorial notice
of Dr. George F. Barker, he felt some hesitancy, beheving that some
-other and closer friend would be better fitted to undertake it. Still,
there had grown to be a strong bond of friendship and sympathy
between Dr. Barker and himself, increasing with the flight of years.
Both began life as chemists, and both spent their earlier years in
teaching that science, while maintaining all along an unbroken inter-
est in its advance. Both were early trained in the mechanical work-
shop as constructors. Together, through many years, they wit-
nessed, and themselves assisted in, that great extension of electrical
science and its applications to the arts and industries, which have
so greatly changed the conduct and convenience of modern life.
Contemporaries they were, from its very inception. They were
fellow delegates to international congresses of electricians, fellow
members of several scientific and technical national societies, includ-
ing the American Philosophical Society.

The writer may be pardoned for adding that in scientific tastes,
there was many a bond of sympathy between them. The great
advances in astro-physics, the researches in chemical physics, the
wonderful discoveries in Roentgen rays, and the later epoch-making
investigations in radio-activity, aroused in them a like interest.
Above all, the friendship that had existed for so many years was of
a. kind which time could but ripen and increase. Dr. Barker was
constant in his attendance on important scientific gatherings, and
active in their work, and when a year or so before his death he was
compelled to remain away owing to illness, his absence was at once
noticed and regretted. His cordial greeting so warmly given and
earnestly reciprocated was missed by his friends, who did not then
know that the end of a most useful life had almost come, and that

xiii

xiv OBITUARY NOTICES OF MEMBERS DECEASED.

they were to see him no more. The writer, since the early seven-
ties when Dr. Barker came to Philadelphia, had enjoyed his friend-
ship and kindly appreciation, and his loss has left a gap never to
be closed.

Nevertheless, he survived many of his associates, if only for a
short time. In 1891 he headed a committee of five members of the
National Academy of Sciences, appointed to report on the Henry
Draper Medal, the others besides Dr. Barker being Wolcott Gibbs,
Simon Newcomb, and C. A. Young, and Professor A. W. Wright,,
who is the only one who now survives. It was when Dr. Barker
took the chair of physics in the University of Pennsylvania that
the writer first had the privilege of his acquaintance. He was then
among the faithful attendants upon the meetings of the American
Philosophical Society, of which he became a member in 1873 and
later, as is well known, served as an officer of the Society, acting as
Secretary from 1877 to 1897, and also as Vice-President, between
1899 and 1908.

The record of the scientific work of Dr. Barker is distinguished
by remarkable versatility. Moreover, his temper of mind was such
that, while giving full worth to research in so-called pure science,,
he did not lose sight of the practical application of scientific prin-
ciples as a most important factor in human progress. As a chemist
he dealt ably with the purely theoretical side of chemical problems,,
yet was an eminent and trusted practical chemist. He "gave a large
fraction of his life's work to abstract physical science, but was ever
keenly interested in engineering. Nor did he fail in extending this
interest to other branches of science besides those which he had
made peculiarly his own. We find him observing transits and solar
eclipses, and making and recording observations in astronomy with
the same ability and enthusiasm which he manifested in chemistry
or physics. Even in his later years we find the same acute interest
in his studies and work in Roentgen rays and radio-activity. It
was also true that at all times he showed for the work of others
a generous appreciation and interest, and when such work com-
mended itself to him he was not slow in assisting towards its proper
recognition.

As a friend and associate he was held in the highest personal

GEORGE FREDERICK BARKER. xv

regard by those who knew him, and his death brought to them a
deep sense of irreparable personal loss. His earnest interest in
science is attested by the numerous papers which form a partial
record of his thought and work, while his fine personal traits remain
to those who new him as a memory which will not soon fade.

In the early Philadelphia days Dr. Barker lectured frequently
in public to large and appreciative audiences. He spared no pains
to interest and instruct those who attended. Was there a new
development or discovery in science, he strove to make his auditors
appreciate it as he did. His mechanical and practical skill was of
great aid in devising and arranging apt and often brilliant experi-
mental illustrations, with which his popular lectures were crowded.
It was the writer's privilege as a young man to be present on a
number of such occasions at the Academy of Music, and he remem-
bers vividly a lecture on electric lighting in which, as a unique
feature, an early Gramme dynamo, secured from abroad by Dr.
Barker, was driven by a gas engine, and used to furnish the elec-
trical current. Before that time a large voltaic battery, almost pro-
hibitive from its cumbersomeness and cost, would have been required
to produce any semblance of the brilliant efifects of the electric arc
then shown. This was at a time when there was but little appre-
ciation of the possible great future growth of electric lighting, and
about two years before the invention of the incandescent lamp by
Edison.

As a natural result, however, we find that Dr. Barker was not
only, from the first, in personal touch with Edison in his pioneer work,
but was one of those deeply interested in his early incandescent lamp
development. More broadly it can be said that throughout his long
service to science, Dr. Barker followed with special ardor the rapid
and important growth of electrical science which has continued in
the intervening years.

When the American Philosophical Society celebrated the 150th
anniversary of its foundation, it was he who, under the title of
"Electrical Progress Since 1743." studiously reviewed the advance
of electrical science due to workers such as Franklin, Faraday,
Hare, Henry and others. As another evidence not only of his deep

xvi OBITUARY NOTICES OF MEMBERS DECEASED.

interest in electrical advancement but of the early recognition of his
foremost position at the time, he was appointed U. S. Commissioner
to the Paris Electrical Exposition held in 1881, and an official dele-
gate to the Electrical Congress then held. This was indeed a famous
congress, by which much work of vital interest and importance was
either accomplished or initiated, particularly concerning the nomen-
clature of the several electrical units, and the evaluation of stand-
ards ; a work which has been continued by the subsequent inter-
national chambers of delegates at each of the important Congresses
held since that time; the last being that at St. Louis in 1904.

At the Paris Exposition of 1881, which was the first exposition
to be devoted to electricity solely. Dr. Barker was also made vice-
president of the Jury of Awards, and in recognition of his services
received the decoration of Commander de la Legion D'Honneur,
an honor accorded to but few Americans. He was also a member
of the U. S. Commission at the Electrical Congress held during the
Philadelphia Electrical Exhibition of the Franklin Institute in 1884.
He served also on the Jury of Awards at the World's Columbian
Exposition in 1893.

During his long connection with the University of Pennsylvania,
his services were valued very hightly by his associates ; he was
always helpful in the solution of the problems presented, and
brought to bear a ripe judgment so as to decide upon the course to
be taken in any case with fairness and calmness. His service to
the community w'as none the less valuable. This was evident in his
work while a member of the Board of Public Education, and his
counsel in relation to such matters as water supply, illuminating
gas and other municipal problems was much esteemed. Dr. Barker
was one of the first to point out the fallacies and trickery of the
famous Keely motor scheme, and to denounce it in the public prints.
This scheme was actively exploited in the late seventies in Phila-
delphia. Needless is it to say that all the subsequent history of that
long-lived fraud, and its final wind-up and exposure upon the death
of Keely amply confirmed the entire justice of Dr. Barker's original
denunciation of it.

As an author and writer he was. as in other things, most careful

GEORGE FREDERICK BARKER. xvii

and conscientious. His text-book on " Elementary Chemistry "
which first appeared in 1870 went through many editions, and was
esteemed as embodying the most advanced thought, presented for
the first time in our language thoroughly and systematically. No
less an authority than Wolcott Gibbs commended the book highly.

Barker's '"Physics, Advanced Course" published in 1892 as one
of the American Science Series, was likewise an embodiment of the
most modern views and met with a hearty reception. The treatment
was mainly from the standpoint of energy and interchanges therein.
and the ether of space was frankly assumed as the fundamental
thing in dealing with all forms of radiation. From his habit of
mind it was to be expected that in his scientific papers we should
also find the results of the latest investigations. He was particular in
giving a comprehensive bibliography of the subject, where it was
possible. Thus, the valuable address delivered by him before the
Chemical Society at Columbia University in March, 1903, is a model
paper. Its subject was " Radio-Activity and Chemistry." and its
great historical value will be understood when it is stated that to it
is appended a bibliography of no less than ninety titles of papers
by the leading investigators.

Some of his earlier papers and addressess assisted to a con-
siderable degree in enforcing the great principles of conservation
and correlation of forces, the discussion of which was carried on
actively in the period between i860 and 1880. Before those years
the ideas of permanence of energy and the importance of energy
interchanges had not received universal recognition or acceptance.
It is now generally recognized that the indestructibility of energy is
a more necessary postulate than the indestructibility of matter.

Dr. Barker's logical mind did not limit itself to the considera-
tion of physical forces merely. He had taken the degree of doctor
of medicine and it was natural that he should be led to consider the
relations between the physical and so-called vital forces. We find
his views expressed in a paper entitled " The Correlation of \^ital
and Physical Forces," published in 1875 by Van Nostrand, and also
in his address as retiring president of the American Association for
the Advancement of Science, at the Boston meeting in 1882. This

PROC. AMER. PHIL. SOC. L. I99*, PRINTED JULY I, I9II.

xviii OBITUARY NOTICES OF MEMBERS DECEASED.

latter address was entitled " Some Modern Aspects of the Life
Question." He identifies vital force or energy as that stored in the
complex protoplasm under physical and chemical conditions only;
a view which more and more guides the biochemists of today in
their researches. The Association address is an excellent example
of clear logical scientific thinking. In it Dr. Barker drew ably from
his rich fund of knowledge in physics, chemistry, biology, and kin-
dred branches. He claims for science its true position as interpreter
of the things which can be known, but points out clearly the limita-
tions of this knowledge.

The writer may be pardoned making a few quotations :

But the properties of bodies are only the characters by which we differ-
entiate them. Two bodies having the same properties would only be two
portions of the same substance. Because life, therefore, is unlike other proper-
ties of matter, it by no means follows that it is not a property of matter.
No dictum is more absolute in science than the one which predicates prop-
erties upon constitution. To say that this property exhibited by protoplasm,
marvellous and even unique though it be, is not a natural result of the con-
stitution of matter itself, but is due to an unknown entity, a tcrtium quid
which inhabits and controls it, is opposed to all scientific analogy and ex-
perience. To the statement of the vitalist that there is no evidence that life
is a property of matter, we may reply with emphasis that there is not the
slightest proof that it is not.

Again, at the close of the address, speaking of the dependence of all
activity on the earth upon solar radiation :

It is a beautiful conception of science which regards the energy which is
manifested on the earth as having its origin in the sun. Pulsating awhile in
the ether, the molecules of which fill the intervening space, this motion
reaches our earth and communicates its i tremor to the molecules of matter.
Instantly all starts into life. The winds move, the waters rise and fall, the
lightnings flash and the thunders roll, all as subdivisions of this received
power.

And further:

But all this energy is only a transitory possession. As the sunlight gilds
the mountain top and then glances off into space, so this energy touches upon
and beautifies our earth and then speeds on its way. What other worlds it
reaches and vivifies, we may never know. Beyond the veil of the seen,
science may not penetrate. But religion, more hopeful, seeks there for the
new heavens and the new* earth wherein shall be solved the problems of a
higher life.

GEORGE FREDERICK BARKER. xix

That the taking up of the teaching of physics by Dr. Barker did
not prevent a continued interest in chemical studies is shown by his
serving as the chairman of the sub-section of chemistry of the Amer-
ican Association in 1876, when he deHvered a notable address on
'' The Molecule and the Atom." In this he points out the impor-
tance of considering the energy interchanges in chemical reactions,
a matter which up to that time had been more or less neglected.
Even as late as 1891, he was honored by being made president of
the American Chemical Society, and delivered an address on the
" Borderland between Physics and Chemistry," in which he dealt
with the necessity for distinguishing the fundamental notion of
" mass " from that of " weight." He further showed the rich harvest
to be expected in the application of the kinetic theory to solutions,,
and concluded by a remarkably clear exposition of what was then
known of the nature of electric forces in their relation to chemical
actions. In these later years, it has indeed been the field of physical
chemistry which has yielded an abundant harvest ; the advances in
it have been of the greatest importance to science. Indeed, the
electro-physicist of today has even split the one time ultimate chem-
ical atom into the more fundamental electrons. We must credit Dr.
Barker with a keen appreciation of the directions in which further
scientific advances were to be made.

None the less clear was his prevision of the future of applied
science. In this connection the writer must content himself by
quoting from a brief paper read at the Saratoga Meeting of the
American Association for the Advancement of Science in 1879.
The title of the paper was '' On the Conversion of Mechanical
energy into Heat by Dynamo Electric Machines." It must be
remembered that at the time the paper was read no practical in-
candescent electric lamp had been made, and industrial electric
development had scarcely begun even with the older arc light. The
quotation reads :

The amount of heat actually obtainable from dynamo electric machines
when worked upon a commercial scale, is a question which in the near
future is to become of very considerable commercial importance. That
electric distribution, at least in our larger cities, is ultimately to be the source
of light supply, is already placed beyond a peradventure. But far more than

XX OBITUARY NOTICES OF MEMBERS DECEASED.

a simple light production is to be expected of this marvellous agent. It must
not only light our houses, but it must warm them and must furnish mechanical
power to them for a thousand petty operations now either done not at all, or
done by manual labor. It must pump the water, raise the elevator, run the
sewing machine, turn the spit, perform its part of the laundry service, and
perhaps even assist in the cooking.

As before indicated, it was natural that the early work of Edison
on the carbon filament lamp should greatly interest Dr. Barker.
This lamp was not brought out until 1880. but we find that it was in
that year tested as a light source by him, acting in collaboration with
Professor Henry A. Rowland. The results were published in the
American Journal of Science, and in the Chemical Nezvs. This
account of early tests was followed in 1881 by papers dealing with
the general subject of electric light photometry and by results of
tests. Dr. Barker was chairman of the Sub-commission on Incan-
descent Lamps at the Paris Electrical Exposition in 1881, the other
members being Wm. Crookes, E. Hagenbach, A. Kundt and E.
Mascart. There is no need to make any comment on the standing
of these men. Their work was in fact pioneer work done at the
start of an industry which today has become one of enormous im-
portance. As the Paris Exposition of 1881 was the first to be
devoted entirely to electricity and its applications, it possessed a pecu-
liar interest. The International Congress of Electricians held at the
same time has been before referred to. Dr. Barker prepared a
report on the proceedings of this congress.

As an example of painstaking and exhaustive work in another
field, by a committee of which he was the head, may be mentioned
the Report of the Committee of the National Academy of Sciences,
on Glucose. The investigation was undertaken at the request of
the Commissioner of Internal Revenue, as the information was
needed as a guide to Congress in legislation concerning the manu-
facture and sale of glucose sugar. The other members of this
committee were W. H. Brewer of Yale, C. F. Chandler of Columbia,
Wolcott Gibbs of Harvard, and Ira Remsen of Johns Hopkins. The
report covers more than 100 pages and must have represented a
great amount of work. The subject is most thoroughly dealt with,
and to the report is appended a complete bibliography.

A dance at the list of writings of Dr. Barker will show at once

GEORGE FREDERICK BARKER. xxi

the great range of subjects about which he had informed himself,
and upon which he was equipped to accompHsh vakiable scientific
work. His alertness of mind, even a few years before his death,
is plainly evident in his later papers on such subjects as radio-
activity and intra-atomic energy in 1903, and before that time in
his discussion of liquefied air, Roentgen rays, wireless telegraphy,
monatomic gases, etc.

From the fact that he survived many of his contemporaries and
associates in scientific work, it was natural that it should have
fallen to his lot to prepare memoirs to some of these to whom he was
most closely drawn. How well the work was done, with what con-
scientious care as to facts, and in what personal estimation he held
these friends, can only be understood by a careful reading of these
memoirs. Coupled with tender remembrances, they show a sincere
admiration for the accomplishments, the discoveries and researches
which he so ably describes. He spared no pains to bring out clearly,
and often in detail, the things for which his friend was best known,
his scientific methods and results, and throughout all this his keen
personal interest and afifectionate regard is manifested. This large-
ness of view and willingness to devote much time and effort to assist
in securing that place in science which his friends' work seemed to
him to deserve, appears to the writer as quite characteristic, and
implies a most generous spirit. Examples of the truth of this
will be found in his memoirs of John William Draper, and of his
son. Dr. Henry Draper, read before the National Academy of Sci-
ences, one in April, 1886, and the other in April, 1888. The elder
Draper died early in 1882, and his son Henry late in the same year.

The splendid achievements of the elder Draper in science and
philosophy are well known, and are most ably dealt with in the
memoir referred to, while Dr. Barker's close personal relations with
Henry Draper gave him excellent opportunities for obtaining the
biographical material which he has incorporated in the memoirs.
Henry Draper devoted himself to optical and astronomical science,
constructing improved instruments and devising new methods. Of
him Dr. Barker writes from the standpoint of a warm personal
friend telling of a most fruitful career too soon closed; a scientist of

xxii OBITUARY NOTICES OF MEMBERS DECEASED.

the highest type stricken in the midst of his hfe work, with the
brighter promises of his future unfulfilled.

A memoir on the eminent chemist and mineralogist, Dr. F. A.
Genth, was read by him before the American Philosophical Society
in 1901, and also before the National Academy of Sciences. For
the latter society he also prepared an extended memoir of
another noted chemist, Matthew Carey Lea ; in which is given a
careful, critical resume of Lea's remarkable investigations and dis-
coveries, chiefly in chemistry, optics and photography. ,

Dr. Barker was born July 14, 1835, at Charlestown, Mass., and
attended school there, afterwards going to Berwick and Yarmouth
academies in Maine, and to Lawrence Academy in Groton, Mass.
When about sixteen he entered as apprentice the establishment of
J. M. Wightman in Boston, a maker of philosophical instruments,
and remained there five years. This apprentice period must have
given a training very valuable to one who was afterward to so freely
use scientific apparatus. After taking the degree of Bachelor of
Philosophy at the Sheffield Scientific School, where he was also
assistant to Professor Silliman, he entered the Harvard Medical
School as a student and assistant in chemistry.

From this time his career as a science teacher and lecturer was
continued with but little interruption. He received the degree of
Doctor of Medicine from the Albany Medical College in 1863. having
completed his medical course there while Acting Professor of Chem-
istry in the school. In 1864 he served as professor of natural sci-
ences in the Western University of Pennsylvania, soon thereafter
going to Yale as demonstrator in the medical department, where in
1867 he was appointed Professor of Physiological Chemistry and
Toxicology, a chair which he held for six years, when he was
appointed Professor of Physics in the University of Pennsylvania.
Beginning in 1873 he continued this work as head of the department
for twenty-seven years, becoming Professor Emeritus in 1900.

Before coming to Philadelphia he had acted as State Chemist in
Connecticut, giving testimony in some noted cases of poisoning. He
was also at times engaged as expert in patent cases, concerning
electric lighting, telephones, batteries and chemical processes.

GEORGE FREDERICK BARKER. xxiii

It was only to be expected that one so able and active as he was
should become the recipient of many honors. Besides those already
mentioned, including positions of honor on important commissions
and the like, he was given the honorary degree of Doctor of Science
by the University of Pennsylvania in 1898, and in the same year,
the degree of Doctor of Laws from Allegheny College and also from
McGill University. He was elected a member of the National
Academy of Sciences in 1876 and later an honorary member of the
Royal Institution of Great Britain. He was also a member of scien-
tific societies in France and Germany. He attended many notable
educational and scientific meetings as a delegate from societies or
from the University which he so long served. He was assistant
editor of the American Journal of Science, from 1868 to 1900, and
contributed for a number of years accounts of the year's progress in
physics, to the annual Smithsonian Reports.

Dr. Barker was married in 1861 to Mary M. Treadway, of New
Haven, who survives him, and had five children, of whom three
daughters are living. He was in his seventy-fifth year when he died
in Philadelphia, last May.

Thus closed a life of great and varied service, one devoted to high
ideals — a striking example of industry and achievement, a life spent
in doing good. Thus ended the career of a lifelong student of
science of an exceptional range of accomplishment, an excellent
teacher, and a man of noblest aspirations. To those who knew him
well there remains the vivid remembrance of his sterling worth and
fine personal qualities.

A list of his principal publications and papers is appended.

Elihu Thomson.
SwAMPScoTT, Mass.,
April, 191 1.

xxiv OBITUARY NOTICES OF MEMBERS DECEASED.

BIBLIOGRAPHY.

1863. The Forces of Nature. An address delivered before the Chemical

Society of Union College, July 22, 1863. Printed separately. Pamph-
let 45 pp., Albany, N. Y., 1863.

1864. Account of the Casting of a Gigantic Rodman Gun at Pittsburg.

Jm. J. Sci., 37, (2). 296-301.
1864. Report of a Trial for Poisoning by Strychnia. Am. J. Medical
Sciences, 43, 399-480.

1866. Principles of Modern Chemistry. Part I. Chemical Philosophy.

(With Benjamin Silliman.) 8vo, pp. 100, Theodore Bliss & Co.,
Philadelphia.

1867. On Silvering upon Glass. .-Ini. J. Sci., 43, (2), 252.

1867. Formic versus Carbonous Acid. Am. J. Sci., 44, (2), 263-264.

1867. On Normal and Derived Acids. Am. J. Sci., 44, (2), 384-398.

1868. Notices of Papers in Physiological Chemistry. On Hoematoidin. On

the Coloring Matter of the Yolk of the Egg. On the Chemical

Constituents of the Supra-renal Capsules. On the Rational Formula

of Urea. Am. J. Sci., 46, (2), 222-^s9-
186&-9. Notices of Papers in Physiological Chemistry. On Formation of

Sugar in the Liver. Am. J. Sci., 46, (2), 379-390; 47, 20-32, 258-270,

373-398; 48, 4CH64.
1870. A Te.xtbook of Elementary Chemistry. Theoretical and Inorganic.

Charles C. Chatfield & Co., New Haven, Conn.
1870. Abstract of the Second Series of Prof. Meissner's Researches on

Electrized Oxygen. Am. J. Sci., 50, (2), 21:^-223.

1870. The Correlation of Vital and Physical Forces. A lecture delivered

before the American Institute, New York, December 31, 1869.
No. 2 University Series, pp. 36, C. C. Chatfield & Co. New Haven.
Canadian Naturalist, 5, 416-437. Les Mondes, 23, 113-117, 151-157,
201-208. Half hours with Modern Scientists (Huxley, Barker, Stirl-
ing, Cope and Tyndall). Vol. 2, pp. ^^7-72. C. C. Chatfield, New
Haven.

1871. On the Rational Formulas of the Oxides of Chlorine and of Oxides

Analogously constituted. Am. Chemist, 2, 1-4.
1871. On Molecular Classification. Am. Clicmisf. i, 359-360.

1871. A Textbook of Elementary Chemistry. Theoretical and Inorganic.

Fifth edition. Charles C. Chatfield & Co., New Haven, Conn.
(Translated into French, Japanese and Arabic.) i2mo, 342 pp.

1872. Acoustic Illustration of the Method by which Stellar Motions are

Determined with the Spectroscope. (Account of address by Alfred
M. Mayer.) Am. Chem., 2, 412-413.
1872. The Chemical Testimony in the Sherman Poisoning Case. Am.
Chem., 2, 441-445.

1872. Note on the Spectrum of the Aurora. Am. J. Sci., 2, (3), 465-466.

Am. Chem., 2, 248-249; Nature, 5, 172-173.

1873. On the Spectrum of the Aurora of October 14, 1872. Avt. J. Sci., 5,

(3). 81-84.

GEORGE FREDERICK BARKER. xxv

875. A New Vertical Lantern Galvanometer. J I. Franklin Inst., 69, 431-437;

Am. J. Sci., 10, (3), 207-212; Proc. Am. Phil. Soc, 14, 440-445;
Phil. Mag., 50, 434-440. Carl Repertorium 12, 46-52.

876. The Molecule and the Atom. (An address to the Chemical Subsection

of the American Association for the Advancement of Science at its
Buffalo meeting.) Proc. Am. Assn. Ad. Sci., 25, 85-107.

876. Chemistry. Johnson's Universal Cyclopedia, Vol. I, pp. 901-906.

877. Improved Method of Obtaining Aletallic Spectra. Read before Na-

tional Academy of Sciences, April, 1877. Rept. Nat. Acad. Sci. for
1883, P- 47. _

878. Magneto-electricity — III. Johnson's Universal Cyclopedia, Vol. IV;

appendix, pp. 1616-1623.
878. On a new Method of Measuring the Pitch of a Tuning-Fork. Proc.

Am. Assn. Ad. Sci., 27, 118-121.
878. On the Microphone of Hughes. Am. J. Sci., 16, (3), 60-63.
878. On the Results of the Spectroscopic Observation of the Solar Eclipse

of July 29, 1878. (A report to Dr. Henry Draper, The Director.)

Proc. Am. Assn. Ad. Sci.. 27, 113-118; Am. J. Sci., 17, (3), 121-125.

878. On the total Solar Eclipse of July 29, 1878. Proc. Am. Phil. Soc, 18,

103-114-

879. On Arago's Experiment showing the Magnetism of a Conductor.

Read before National Academy of Sciences, October, 1879. Rept.
Nat. Acad. Sci. for 1883, p. 51.

879. Instructions for Disinfection. (George F. Barker, C F. Chandler,
Henry Draper, Edward G. Janeway, Ira Remsen, S. O. Vander
Poel.) The National Board of Health, leaflet, 1879.

879. On the Conversion of Mechanical Energy into Heat by Dynamo-
Electric Machines. Proc. Am. Assn. Ad. Sci., 28, 160-169.

879. On a Curious Case of Crystallization of Canada Balsam. Proc. Am.
Assn. Ad. Sci., 28, 169-172.

879. Note on J. C. Draper's paper " On the Presence of Dark Lines in the

Solar Spectrum which correspond closely to the lines of the Spec-
trum of Oxygen." (A critical review.) Am. J. Sci., 17, (3), 162-
166; Spettrosc. Ital. Mem., 8, 16-20.

880. Report on the Manly Telegraph Cable. Pamphlet 8vo, 15 pp., Phila-

delphia.
880. On Condensers for Currents of High Potential. Read before National

Academy of Sciences. November, 1880. Rept. Nat. Acad. Sci. for

1883, p. 53.
880. On the Efficiency of Edison's Electric Light (with H. W. Rowland).

Am. J. Sci., 19, (3), 337-339', Chem. Nczi's, 41, 200-201.

880. Report on the Contamination of the Water of the Schuylkill River.

Pamphlet, 8vo, 15 pp., Philadelphia, Pa., 1880.

881. Some Modern Aspects of the Life-Question. Address as retiring

President at the Boston meeting of the American Association for
the Advancement of Science in 1880. Proc. Am. Assn. Ad. Sci., 29,
1-30; Revue scientif.. 4, 225-235, 1882.

xxvi OBITUARY NOTICES OF MEMBERS DECEASED.

1881. On the International Congress of Electricians at Paris. Am. J. Sci.,

22, (3), 395-396.
1881. On Electric Light Photometry. Read before National Academy of

Sciences. April 1881. Rept. Nat. Acad. Sci. for 1883, p. 53.
On the Condenser Method of Measuring High Tension Currents.

Read before National Academy of Sciences, April, 1881. Rept. Nat.

Acad. Sci. for 1883, p. 53.
1881. On the Carbon Lamp-fiber in the Thermo balance. Read before

National Academy of Sciences, April, 1881. Rept. Nat. Acad. Sci.

for 1883, p. 53-
On Incandescent Lights. Read before National Academy of Sciences,

April, 1881. Rept. Nat. Acad. Sci. for 1883, p. 53.
Physics (An Account of Recent Progress). Ann. Rept. Smith. Inst.

for 1879-80, 235-288.
Chemistry (An Account of Recent Progress). Ann. Rept. Smith. Inst.

for 1879-80, pp. 289-297.
On Mascart's Electrometer and Its Use as a Meteorological Instru-
ment. Read before the National Academy of Sciences, November,

1881. Rept. Nat. Acad. Sci. for 1883, p. 54.

1881. An Account of Recent Progress in Physics and Chemistry (For the
Years 1879 and 1880). From the Smithsonian Report for 1880.
Pamphlet, 8vo, pp. 2 + 6^.

On the Results of the Incandescent Lamp Tests at the Paris Exhibi-
tion. Read before National Academy of Sciences, April, 1882. Rept.
Nat. Acad. Sci for 1883, p. 54.

1882. On an Improved Form of Standard Daniell Cell. Read before National
Academy of Sciences, November, 1882. Rept. Nat. Acad. Sci. for
1883, p. 55.

r882. Report of the Sub-Commission on Incandescent Lamps at the Inter-
national Exhibition of Electricity, Paris, 1881. (George F. Barker.
William Crookes, Ed. Hagenbach, A. Kundt, E. Mascart.) Pamphlet,
8vo, 28 pp.. New York.
On Secondary Batteries. Proc. Am. Assn. Ad. Sci., 31, 207-217;
Clicm. Nezvs, 47, 196-199, 1883.

[882. Henry Draper. A minute prepared as Secretary of the American
Philosophical Society. Proc. Am. Phil. Soc, 20, 656-662, December,
1882.
Physics (An Account of Recent Progress). Ann. Rept. Smith. Inst
for i88a-8i, pp. 2,2,3,-i79-

1883. Chemistry (An Account of Recent Progress). Ann. Rept. Smith.
Inst, for i88o-8r, pp. 381-390.

1883. An Account of Progress in Physics and Chemistry in the year 1881.
From the Smithsonian Report for 1881. Pamphlet, 8vo, pp. 2 + 58.
1883. The Future of American Science. (Anon.) Science, 1, 1-3.

Henry Draper. A Biographical Notice. Am. I. Sci., 25, (3), 89-95.
On the Variability of the Law of Definite Proportions. Am. I. Sci.,
26, (3). 63-67.

GEORGE FREDERICK BARKER. xxvii

5883. On the Measurement of Electromotive Force. Proc. Am. Phil. Soc,

21, 649-655.
1883. Report of Committee on Methylated Spirits. (Ira Remsen, C. F.

Chandler, George F. Barker.) Rept. Nat. Acad. Sci. for 1883, pp.

57^3-
1883. Report of Committee on Glucose. (George F. Barker, William H.
Brewer, Wolcott Gibbs, Charles F. Chandler, Ira Remsen.) Rept.
Nat. Acad. Sci. for 1883, pp. 65-143.

1883. Efificiency of Storage Batteries. Read before National Academy of

Sciences, April, 1883. Rept. Nat. Acad. Sci. for 1883, p. 56.

1884. On a Lantern Voltameter. Read before the National Academy of

Sciences, April, 1884. Rept. Nat. Acad. Sci. for 1884, p. 6.
1884. On the Fritts Selenium Cell. Read before the National Academy of

Sciences, April. 1884. Rept. Nat. Acad. Sci. for 1884, p. 6.
1884. Physics (An Account of Progress in the year 1882). Ann. Rept.

Smith. Inst, for 1881-82, pp. 459-508. Separate, 1883, 8vo, pp. 2 + 50.
1884. Report on Glucose (Committee of Nat. Acad. Sci. Geo. F. Barker,

Chairman). Govt. Print. Off., Pamphlet, 8vo, 108 pp.. Wash.
1884. The British Association at Montreal. Am. J. Sci., 28, (3), 300-303.
1884. The American Association at Philadelphia. Am. J. Sci., 28, (3),

303-307-
1884. The National Conference of Electricians at Philadelphia. Avi. J. Sci.,
28, (3), 386-390.

1884. Shall the Ammonium Theorj- be Applied to Alkaloidal Salts? (Sym-

posium.) IVeekly Drug News and Prices Current, 9, 705-706.

1885. Physics (An Account of Progress in the Year 1883). Ann. Rept.

Smith. Inst, for 1882-83. pp. 571-628. Separate, 1884, 8vo. pp. 2 + 52.

1885. On the Use of Carbon Bisulphide in Prisms. Being an account of
Experiments made by the late Dr. Henry Draper of New York.
Am. J. Sci., 29, (3), 269-277.

1885. Report of Committee on Philosophical and Scientific Apparatus.
(George J. Brush. Wolcott Gibbs. Samuel H. Scudder, Simon New-
comb, George F. Barker.) Rept. of Nat. Acad. Sci. for 1884, pp.
65-67.

1885. Physics (An Account of Progress in the j'ear 1884). Ann. Rept.

Smith. Inst, for 1883-84, pp. 433-489. Separate, 1885. 8vo, pp. 2 + 57.
i886. Memoir of John William Draper, 1811-1882. Read before Nat. Acad,
of Sci., April, 1886. Biographical Memoirs. Nat. Acad. Sci., 2,
349-388.

1886. Protection of (Philadelphia) Public Buildings (City Hall) from

Lightning. Rept. Commissioners for the Erection of " The Public
Buildings." pp. 25-28, Philadelphia, 1886.

1886. Physics (An Account of Progress in the Year 1885). Ann. Rept.

Smith. Inst. 1884-85, pp. 577-636. Separate, 1886, 8vo, pp. 2 + 60.
i886. Telephone. Johnson's (revised) Universal Cyclopedia, 7, 736-737.

1887. On the Henry Draper Memorial Photographs of Stellar Spectra.

Proc. Am. Phil. Soc. 24, 166-171.

xxviii OBITUARY NOTICES OF MEMBERS DECEASED.

1889. Physics in 1886 (An Account of Progress in the Year 1886). Ann.
Rept. Smith. Inst, for 1886-87, pp. 327-386. Separate, 1889, 8vo,
pp. 60.

1891. On Zinc Storage Batteries. Read before the National Academy of
Sciences, November, 1889. Report Nat. Acad. Sci. for 1889, p. 12.

1891. Report of Committee appointed by the National Academy of Sciences
on the Henry Draper Medal. (George F. Barker, Wolcott Gibbs,
Simon Newcomb, Arthur W. Wright, C. A. Young.) Rept. Nat.
Acad. Sci. for 1889, pp. 53-63.

1891. A Textbook of Elementary Chemistry, Theoretical and Inorganic.
Revised and Enlarged. 8vo, 348 pp. John P. IMorton & Co., Louis-
ville, Ky.

1891. The Borderland between Physics and Chemistry. Address as Presi-
dent of the American Chemical Society. /. Am. Chem. Soc, 13, 13-29.

1891. The Physiology of Manual Training. An address at the Opening of
the Williamson Free School of Mechanical Trades. The Williamson
Free School of Mechanical Trades. Pp. 61-69, Philadelphia, 1891.

1891. The Modern View of Energy. Syllabus of a Course of Six Lectures.

University Extension Lectures of Am. Soc. for Ex. of Univ. Teach-
ing. Series A, No. 30, pp. 16, 1891.

1892. A Textbook on Physics. Advanced Course. Lg. 8vo, 902 pp. (Ten

editions.) American Science Series, Henry Holt & Co., N. Y.

1893. On the Storage of Electrical Energy. A'^. Y. Independent, 45, 280-281.

1894. Electrical Progress since 1743. A Paper read before the American

Philosophical Society on the Occasion of the Celebration of the
150th Anniversary of its Foundation, May 27, 1893. Proc. Am.
Phil. Soc, 32, 104-154.

1895. Memoir of Henry Draper. Read before Nat. Acad, of Sci. April, 1888.

Biographical Memoirs Nat. Acad. Sci., 3, 81-139.
1897. Sketch of Moses Gerrish Farmer. An address before the American
Institute of Electrical Engineers at Greenacre, Me., July 20th, 1897.
Trans. Am. Inst. Electrical Engineers, 14, 414-417.

1897. The American Philosophical Society. A paper read at the Greenacre

Conference, July, 1897. Electrical Eng., 24, 90.

1898. Liquefied Air. A lecture delivered before the Scientific Association of

Johns Hopkins University, March 24, 1898. Bait. Am., March 25.

1898. Address on Alexander Dallas Bache, made on Presentation of Por-
trait to the Bache Public School of Philadelphia, April 13, 1898.
Presentation of the Portrait of Professor Alexander Dallas Bache,
pamphlet, pp. 12-17, Philadelphia.

1898. Rontgen Rays. Memoirs by Rontgen, Stokes and J. J. Thomson.
Translated and edited by George F. Barker. Sm. 8vo, 82 pp.
Scientific Memoir Series. Harper and Brothers, New York.

1898. Liquid Air. A Lecture delivered before the Friends Institute Lyceum,

Philadelphia, Pa. Sci. Am. Sup., Sept. 24, pp. 19021-19022, 19036-
19037. The Chautauquan, 27, 526-529.

1899. Wireless Telegraphy through Scientific Eyes. Lippincoit's Mag.,

64, 301-31 1. ,;

GEORGE FREDERICK BARKER. xxix

1899. The Hydrogen Vacua of Dewar. Read before the National Academy
of Sciences. Rept. Nat. Acad. Sci. for 1899, p. 13.

1899. Air as a Liquid. X. Y. Independent, May 25, pp. 1419-1422.

1901. Memoir of Frederick Augustus Genth. Read before the American
Philosophical Society. December 6, 1901. Proc. A»i. Phil. Soc, 40
(Obituary Notices), X-XXIL

1901. The Monatomic Gases. Read before the National Academy, Novem-
ber, 1901. Rept. Nat. Acad. Sci. for 1901, p. 16.

190 1. On the Newer Forms of Incandescent Electric Lamps. Read before

the National Academy. November, 1901. Rept. Nat. Acad. Sci. for
1901, p. 16.

1902. Biographical Memoir of Frederick Augustus Genth, 1820-1893. Read

before the National Academy of Sciences, November 12, 1901.
Biographical ^lemoirs Nat. Acad. Sci., Vol. 5, 202-231.

1903. Radioactivity and Chemistry. An address delivered before the Chem-

ical Society of Columbia University, March 19, 1903. School of
Mines Quarterly, 24, 267-302.
1903. On the Radioactivity of Thorium Minerals. Read before the Na-
tional Academy of Sciences, April, 1903. Am. J. Sci., 16, (4), 161-
168.

1903. Intratomic Energy; the L'nmeasurable Force of Inanimate Nature.

A^. Y. Sun, p. 6, July 12.

1904. On Radioactivity and Autoluminescence. Read before the National

Academy of Sciences, April, 1904. Rept. Nat. Acad. Sci. for 1904,
P- 13-

1905. Biographical Memoir of Matthew Carey Lea, 1823-1897. Read before

the National Academy of Sciences, April, 1903. Biographical Mem-
oirs Nat. Acad. Sci., Vol. 5. 154-208.

MAGELLANIC PREMIUM

Founded in 1786 by John Hyacinth de Magellan, of London
191 I

THE AMERICAN PHILOSOPHICAL SOCIETY

Held at Philadelphia, for Promoting Useful Knowledge

ANNOUNCES THAT IN

DECEMBER, 1911

IT WILL AWARD ITS

MAGELLANIC GOLD MEDAL

TO THE AUTHOR OF THE BEST DISCOVERY, OR MOST USEFUL INVENTION, RE-
LATING TO NAVIGATION, ASTRONOMY, OR NATURAL PHILOSOPHY (mERF
NATURAL HISTORY ONLY EXCEPTED) UNDER THE FOLLOWING CONDITIONS :

1. The candidate shall, on or before November i, 191 1, deliver free of postage
or other charges, his discovery, invention or improvement, addressed to the
President of the American Philosophical Society, No. 104 South Fifth Street,
Philadelphia, U. S. A., and shall distinguish his performance by some motto,
device, or other signature. With his discovery, invention, or improvement, he
shall also send a sealed letter containing the same motto, device, or other sig-
nature, and subscribed with the real name and place of residence of the author.

2. Persons of any nation, sect or denomination whatever, shall be ad-
mitted as candidates for this premium.

3. No discovery, invention or improvement shall be entitled to this premium
which hath been already published, or for which the author hath been publicly
rewarded elsewhere.

4. The candidate shall communicate his discovery, invention or improvement,
either in the English, French, German, or Latin language.

5. A full account of the crowned subject shall be published by the Society,
as soon as may be after the adjudication, either in a separate publication, or in
the next succeeding volume of their Transactions, or in both.

6. The premium shall consist of an oval plate of solid standard gold of the
value of ten guineas, suitably inscribed, with the seal of the Society annexed to
the medal by a ribbon.

A.11 correspondence in relation hereto should be addressed

To THE Secretaries of the

AMERICx\N PHILOSOPHICAL SOCIETY

No. 104 Soi th Fifth Street

PHILADELPHIA, U. S. A.

The American Philosophical Society

Announces that an Award of the

HENRY M. PHILLIPS PRIZE

will be made during the year 191 2 ; essays for the same to
be in the possession of the Society before the first day of
January, 1912.

The subject upon which essays are to be furnished by
competitors is :

The Treaty-making power of the United States
and the methods of its e7iforcement as affect-
ing the Police Powers of the States.

The essay shall contain not more than one hundred thousand words, ex-
cluding notes. Such notes, if any, should be kept separate as an Appendix.

The Prize for the crowned essay will be ^2,000 lawful gold coin of the
United States, to be paid as soon as may be after the award.

Competitors for the prize shall affix to their essays some motto or name
(not the proper name of the author, however), and when the essay is
fo-warded to the Society it shall be accompanied by a sealed envelope,
containing within, the proper name of the author and, on the outside
thereof, the motto or name adopted for the essay.

Essays may be written in English, French, German, Dutch, Italian,
Spanish or Latin ; but, if in any language except English, must be accom-
panied by an English translation of the same.

No treatise or essay shall be entitled to compete for the prize that has
been already published or printed, or for which the author has received
already any prize, profit, or honor, of any nature whatsoever.

All essays must be typewritten on one side of the paper only.

The literary property of such essays shall be in their authors, subject to
the right of the Society to publish the crowned essay in its Transactions
or Proceedings.

The essays must be sent, addressed to

The President of the American Philosophical Society,
No 104 South Fifth Street, Philadelphia, Penna., U. S. A.

4 i'^ 5

PROCEEDINGS

OF THE

American Philosophical Society

HELD AT PHILADELPHIA

FOR PROMOTING USEFUL KNOWLEDGE

Vol. L. July-August, 191 i. No. 200.

CONTENTS.

Symposium — The Modern Theory of Electricity and Matter.

I. The General Principles. By Daniel F. Comstock 321

II. Radioactivity. By Bertram B. Boltwood 333

III. The Dynamical Effects of Aggregates of Electrons. By Owen W.

Richardson 347

IV. The Constitution of the Atom. By Harold A. Wilson, F.R.S 366

The High Voltage Corona in Air. By J. B. Whitehead 374

Disruptive Discharges of Electricity Through Flames. By Francis E. Nipher 397

The Desert Group Nolineae. By William Trelease 405

Isostasy and Mountain Ranges. By Harry Fielding Reid 444

A Fossil Specimen of the Alligator Snapper (Macrochelys temminckii) from

Texas. By Oliver P, Hay 452

PHILADELPHIA

THE AMERICAN PHILOSOPHICAL SOCIETY

104 South Fifth Street

1911

MAGELLANIC PREMIUM

Founded in 1786 by John Hyacinth de Magellan, of London

191 I

THE AMERICAN PHILOSOPHICAL SOCIETY

Held at Philadelphia, for Promoting Useful Knowledge

ANNOUNCES THAT IN

DECEMBER, 1911

IT WILL AWARD ITS

MAGELLANIC GOLD MEDAL

TO THE AUTHOR OF THE BEST DISCOVERY, OR MOST USEFUL INVENTION, RE-
LATING TO NAVIGATION, ASTRONOMY, OR NATURAL PHILOSOPHY (mERE
NATURAL HISTORY ONLY EXCEPTED) UNDER THE FOLLOWING CONDITIONS :

1. The candidate shall, on or before November i, 1911, deliver free of postage
or other charges, his discovery, invention or improvement, addressed to the
President of the American Philosophical Society, No. 104 South Fifth Street,
Philadelphia, U. S. A., and shall distinguish his performance by some jnotto,
device, or other signature. With his discovery, invention, or improvement, he
shall also send a sealed letter containing the same motto, device, or other sig-
nature, and subscribed with the real name and place of residence of the author.

2. Persons of any nation, sect or denomination whatever, shall be ad-
mitted as candidates for this premium.

3. No discovery, invention or improvement shall be entitled to this premium
which hath been already published, or for which the author hath been publicly
rewarded elsewhere.

4. The candidate shall communicate his discovery, invention or improvement,
either in the English, French, German, or Latin language.

5. A full account of the crowned subject shall be published by the Society,
as soon as may be after the adjudication, either in a separate publication, or in
the next succeeding volume of their Transactions, or in both.

6. The premium shall consist of an oval plate of solid standard gold of the
value of ten guineas, suitably inscribed, with the seal of the Society annexed to
the medal by a ribbon.

Ml correspondence in relation hereto should be addressed
To THE Secretaries of the

AMERICAN PHILOSOPHICAL SOCIETY
No. 104 South Fifth Street

PHILADELPHIA, U. S. A.

, D 1 '

PROCEEDINGS

OF THE

AMERICAN PHILOSOPHICAL SOCIETY

HELD AT PHILADELPHIA
FOR PROMOTING USEFUL KNOWLEDGE

Vol. L July-August, ]911 No. 200

SYMPOSIUM.

THE MODERN THEORY OF ELECTRICITY AND

MATTER.

I.

THE GENERAL PRINCIPLES.

By DANIEL F. CO^ISTOCK.
{Read April 23, igii.)

The field of the present discussion is so large and the time for
it is so limited that I feel sure I can serve you best by foregoing the
luxury of an historical introduction and by entering somewhat
abruptly into the heart of the subject before us. I wish, then, to
discuss before you the general ideas and beliefs respecting the ulti-
mate nature and relations of matter and electricity which are in the
foreground at the present time.

In dealing with progress of scientific explanation it is necessary
to remember, what we too often forget, that the verb " to explain,"
when applied to a new complex phenomenon, means mereiy the ex-
pressing of it in terms of something else either more fajiiiliar or
more fuiidaiiicutal. An exaggerated example of the first type is
furnished by all the old anthropomorphic explanations of natural

PROC. AMER. PHU.. SOC. , L. 200 U, PRINTED JULY 3I, igil.

321

322 COMSTOCK— THE MODERN THEORY [April 22,

phenomena in which the less famiHar actions of the outside world
were expressed in terms of the intimate and much more familiar
workings of the human mind. " Nature abhors a vacuum," and like
expressions, show the type.

The progress of science exhibits countless examples of the
second type of explanation, for, wherever two or more concepts are
merged into a profounder synthesis, there we have an expression in
terms of something more jundamcntal. When, for instance, it is
said that the phenomena of tidal action are caused by the gravita-
tional attraction of the moon, it is stated merely that this action is
really one with countless other phenomena which, although dis-
similar on the surface, merge with it into the profounder synthesis
known as the law of gravitation.

It is important also to remember in this connection, that /;; this
process of explanation we always have left the one concept into
which the many have merged, so that as time goes on the alterna-
tives of explanation grow fewer and fewer, and in the end — if we
can imagine an end — there is no explanation, because there is no
more fundamental fact.

You will pardon me, I am sure, if I say one word more with
reference to this question of ultimate explanation.

We have all heard people say, " Isn't it wonderful that so much
is known about electricity, and yet no one knows what electricity
\s !" Now, doubtless the observation has some meaning, but cer-
tainly not as much as it seems to have; for, after all, what do they
mean by " what electricity is " ? Do they expect the announcement
some day that electricity is a liquid similar to water, or a gas similar
to air?

It is becoming more and more probable that electricity is the
chief constituent of the atoms themselves, and an electron, which is
a particle of electricity, if anything is, is certainly less than a ten-
thousandth the size of one of the atoms in a water molecule. There-
fore after the " Is^' following the word " electricity," there is noth-
ing to put which is already familiar, and when the profounder con-
cept does come, it will be extremely fundamental, but it will cause
the layman no thrill of long-anticipated disclosure.

A special type of critical attitude is necessary in dealing with

191 1.] OF ELECTRICITY AND MATTER. 323

fundamental physical concepts and it is an attitude which we seldom
assume, so that these remarks have been necessary to introduce
properly the three fundamental realities which modern physical
theory now contemplates, namely: the atom, the electron, and that
mysterious but perhaps even more fundamental entity known as
energy.

A few years ago I would have mentioned also the ether, but I
am a little reluctant to do so now. Xot that there has been a sudden
revolution in the realm of thought, resulting in the complete over-
throw of the old regime, but rather that development has been such
as to render the concept of an ether less and less impressive — one
might say — and less and less important. Changes of opinion in
such matters are, it seems to me, partly questions of emphasis, and
radiant energy in all its nakedness is now usurping much that the
ether has long stood for.

Of course, the loss, or rather the dimness, of the ether concept
implies a certain loss of concreteness ; but, as has been said, con-
creteness in new concepts, founded as it is on familiarity, is a
secondary virtue and is of far less importance than the value of a
concept in furthering the great process of induction which leads us
to more and more general truths.

Although the concept of the ether is slowly dimming, the concept
of the atom is becoming more and more definite and vivid. The
study of the scintillations caused by radium rays and the work of
Rutherford in counting the alpha particles give us, for the first time
in the history of physics, definite observable results which apparently
can only be due to the action of single atoms, and which therefore
furnish proof beyond reasonable doubt that the atom and molecule
are names of actual realities, and are not merely two prominent
words in the statement of a useful hypothesis.

The kinetic theory of matter, carrying with it the concept of
temperature as violence of atomic vibration, has also been strength-
ened enormously by the work of Perrin and Einstein on the Brown-
ian movement. They find that microscopic particles in solutions
have a perpetual motion in close agreement with the kinetic theory.
Indeed, they act in all ways like big molecules, obeying the kinetic
laws deducible from mechanics. Their observable agitation is part

32 i COMSTOCK— THE MODERN THEORY [-Mmi 22,

of the general vibratory motion which (Hstinguishes a hot body from
a cold one.

The electron, too, is now well within what we might call " the
exclusive circle of the truly real." This minute charged body has
by manv researches, among them the recent one of ^Slillikan, been
shown to be a definite reality, present in all matter and entirely or
largely responsible for all the phenomena we know as electrical.

The other fundamental entity, energy, is also, if I may be allowed
the phrase, " mysteriously real." Radiant energy leaves the sun
eight minutes before it reaches the earth, and must, therefore, exist
during that time in the space between, dissociated from ordinary
matter. When it finally strikes some object and is absorbed, it gives
the object a thrust — that is, communicates momentum to it, as a
bullet would do — and at the same time, of course, it increases the
total energy of the body. In the same way, a body radiating energy
recoils during the emission in a way similar to a gun.

All this is remarkably like the action of ordinary matter. We
can, however, say even more. There is very good reason for be-
lieving that, were it possible to shut up a large amount of radiant
energy in a hollow box, the inner surfaces of which were perfectly
reflecting, so that the rays would be reflected back and forth indefi-
nitely, we would find this confined energy to possess both mass and
weight. Not many decades ago such an idea would have seemed
absurd, l)ut it is hard now to avoid the conclusion that such would
be the case.

I can do no better now than to descril)e in a few words the pic-
ture which we have today of the ultimate structure of matter. A
piece of matter is composed of particles called atoms, which, by
uniting in groups in various ways, form the characteristic aggre-
gates which we know as molecules. There are about one hundred
different kinds of atoms, varving in relative weiglits from one to 240,
and in relative volumes from one to about 16. The approximate
diameter of an atom is one one-hundred-millionth of a centimeter.

These atoms are in ceaseless motion to and fro, the energy of
this motion determining what we call the temperature of the body.
Within the atoms and in the spaces between them are large numbers
of very much smaller particles known as electrons. They each

19".] OF ELECTRICITY AND MATTER. 325

carry a negative charge, which is relatively enormous, considering
the fact that the approximate electronic diameter can scarcely be
more than one one-hundred-thousandth that of the atom.

When any cause sets up a general movement of the electrons
within a body, we have a current of electricity, while the random
vibratory heat motion of atom and electron is the cause of continual
emission of radiant energy to other objects or to outside space.

A piece of matter is thus a complex system composed of an in-
conceivably large number of ultimate units, atoms and electrons, in
ceaseless motion to and fro, and permeating all is the mysterious,
matter-like entity which we have called radiant energy, and which
ever seeks to escape with an enormous, though perfectly definite,
velocity into the space outside. Some of it succeeds in escaping,
but there appears to be a vast amount which in some way is im-
prisoned in the atom-electron aggregate and thus never becomes
" radiant " in the strict sense of the word, though it resembles
radiant energy so closely as almost to warrant the same name.

Having thus obtained an impressionistic view of the structure
of a piece of matter, I would like to call attention to the properties
of the space surrounding an electron, or, what is the same thing for
our present purpose, the space surrounding any body, say a small
sphere, possessing an electric charge. This space is the seat of what
we call electric force, and is known as an " electric field." Now, it
is a well-known conclusion and one which cannot at present be in
any way avoided, that the energy which the body possesses, by virtue
of its charge, that is, the energy originally required to charge it,
resides in the electric field around the body, and not on or in the
body itself. The existence, without apparent motion, of this energy
in what seems to be empty space is very remarkable, but the con-
clusion that it is there is unavoidable, and after all there is no great
difiference between the discarnate state of this energy and the state
of the radiant energy of the sun on its way to the earth. From
the older point of view this energy in the electric field was " strain
energy " in the ether, the so-called strain being similar to wdiat we
would get in an immense block of rubber if a pin-head embedded at
its center were to swell into the size of an egg. The rubber would
be pushed back in all directions and the energy of this compression

326 COMSTOCK— THE MODERN THEORY [April 22,

would be stored up throughout the whole mass, a great deal of it
near the center, but an appreciable amount even out at the very
limits of the block. From the present point of view, we think more
about the energy and less about the ether, but the general effect is
the same.

Let us call this energy located in the space surrounding an
electric charge " bound energy," to distinguish it from the closely
similar type of self-propagating energy which can also exist in
space and to which we apply the term " radiant," and let us then
ask what properties, if any, this bound energy gives to the body
which it surrounds.

I stated before that radiant energy, when it struck a body, com-
municated momentum to it in the same general way as a material
body, say a flying bullet, would do. The radiant energy thus acts
as if it had mass, and the question now is, "May the 'bound
energy ' surrounding our charged sphere also be considered to
possess mass?" We may answer this question /;; flic affirmative,
for this bound energy is electric energy, and, thanks to the great
founders of electrical science, we know the laws of electric action
pretty completely.

Applying these well-known laws we find that when our charged
sphere is moved, it acts like a current of elecricity and sets up a
magnetic field about it, and the formation of this field acts, by the
well-known laws of induction, to retard the motion of the charge.
Thus the setting in motion of the sphere is made more difficult by
reason of its charge, an eft'ect which is equivalent to saying that
the sphere has added mass.

If this were all, we might say that the added charge of elec-
tricity had mass, so that the mass increment is on the surface of
the sphere where the charge is known to reside. This is not all,
however, for by letting the sphere expand we can decrease the
energy in the space about it without changing the magnitude of its
charge ; and we find, by further simple application of well-known
electrical laws, that the new mass will change exactly as the energy
changes. If the new mass had been proportional to the charge, it
would remain constant with it instead of changing with the energy.
Thus what is known as the electromagnetic mass of the sphere is

ipii.] OF ELECTRICITY AND MATTER. 327

proportional to its energy. I was able to show, several years ago,
that, with certain limitations, this same result is true for any electric
system.

It may be said, then, to follow from what might be called ele-
mentary electromagnetic principles, that the electromagnetic mass of
an electric system is proportional to its electric energy. Now
Hasenhorl, at Plancks's suggestion, I believe, had already shown
that a similar result applied to radiant energy properly speaking;
for he found that from known laws of radiation it followed that a
hollow box, like that mentioned earlier, with perfectly reflecting
walls, would, when filled with radiant energy, act as if it had added
mass. That is, the pressure of radiation would be so changed by the
increasing velocity of the box as to oppose the force causing this
increase, and this inertia, this added mass, he found would be
proportional to the amount of energy present. My proportionality
constant agrees with his. Lewis, from a totally different point of
view, has reached a similar conclusion.

It is, as you know, one of the profoundest generalizations in
modern physics that light and other forms of radiant energy are in
reality all forms of electromagnetic energy. Hasenhorl's results,
therefore, that confined radiant energy possesses mass, combined
with the result obtained in connection with the bound energy sur-
rounding electric charges, gives us the general result that all elec-
tromagnetic energy, whether bound or radiant, possesses mass, and
this mass is proportional to the quantity of energy present.

You see that the concept of energy, although in some ways very
illusive, is getting singularly definite and persistent. Since we see
that electric mass is proportional to electric energy, the question
naturally arises : How much of the mass of the electron is due to
the electric energy surrounding its relatively enormous charge, and
how much is the "ordinary mechanical mass" of its body proper?
We have a means of distinguishing between the two masses, for
the electric mass does not remain constant when the velocity of the
charge becomes great. Electrical laws tell us that it increases, very
slowly at first, then more rapidly, and that as the velocity of light
is approached it becomes very great. Of course, in ordinary me-

328 COMSTOCK— THE MODERN THEORY [April 22,

chanics, on the other hand, the mass of a body is considered to be a
constant and to have nothing whatever to do with the velocity.

By studying experimentally the deflection of the beta-rays of
radium, which consist of streams of electrons travelling at veloci-
ties very near that of light, Kaufmann has shown that the experi-
mental change in mass fits the mathematically deduced change
wdien, and only when, the '* ordinary mechanical mass " is negligible.
In other words, as near as measurement can yet go, the mass of the
electron is enfirclx the electromagnetic mass of the surrounding
energy, and it has no appreciable mass of what I might call " the
old-fashioned mechanical kind."

This is a result of extraordinary importance in physical theory,
for it immediately suggests the general cjuestion, " Is all mass of this
origin ? " Since an ordinary piece of matter is permeated with
electrons and also with the radiant energy which all parts of it are
constantly absorbing and emitting, it is an absolutely unavoidable
conclusion that at least part of the total mass is of this electro-
magnetic type. I')Ut the question is, " Is all mass electromagnetic?"
or, more properly speaking, " Is all mass of the saiiic type, and docs
it all depend upon the velocity in this same -iCay;^ " An aflirma-
tive answer would imply a profounder unity in physical phenomena
than has hitherto been recognized and would thus correspond to the
passage to a deeper synthesis. Of course, the deeper concept which
unites two or more others should, in strictness, be made independent
of these others ; but, although definitely foreshadowed in the present
case, the detailed statement of this deeper law is at present im-
possible except as regards chaiu/cs due to motion; so that this,
taken with the fact that electromagnetic phenomena are so familiar
that we may be said to know their }nodus operandi in terms of
magnetic fields, electric forces, and the like, renders it provisionally
allowable to state the question in the form: "Are the laws of elec-
tricity and optics the laws of matter in general ? "

We have, during the last few years, been attaining with greater
and greater surety a definite answer to this question. It has come
through the gradual adoption of a remarkable concept, profound in
its meaning and very far-reaching in its consequences. I refer to
the so-called " l^-inci])le of Relativity."

191 1.] OF ELECTRICITY AND MATTER. 329

There are times in tlie history of science when various contra-
dictions require that the process of building stop until the most
fundamental concepts are reexamined. This was true in the his-
tory of astronomy at the time of Copernicus. The prevailing con-
ception of the earth as a fixed center about which all the other
bodies revolve had been practically sufficient for a long time, but
gradually difficulty after difficulty arose until it was no longer
possible to patch up the old theory to meet the accumulation of
stubborn facts. Only by a change in the most fundamental con-
ception, namely, that of the earth as a fixed center, could harmony
be brought out of chaos and a new period of development com-
menced. We seem to be passing through a somewhat similar
period in physics, and the " Principle of Relativity " contains the
modified concepts.

By way of transition, let me make one or two statements at this
point about electric and magnetic systems in general. It can readily
be shown to follow from known electromagnetic laws that two
electric charges of the same sign moving side by side with the
same velocity repel each other less than when the two are stationary.
This is due largely to the fact that, when moving, each charge is
surrounded by a magnetic field and this magnetic field introduces
new forces.

This simple statement introduces a far more general one, for it
may be shown that a steady motion of any electromagnetic system
so changes the force between the various parts of the system that it
tends to take up a new position of equilibrium. The forces arc such
that the icholc system tends to contract along the line of motion.
If it be allowed so to contract until it reaches this new position of
equilibrium, then everything will be as before the system was set in
motion, with two important exceptions, if the system has any in-
ternal motions caused by electromagnetic force. First, two mo-
tions, say the oscillation of two charges, one in the front of the
system and the other behind, which in a stationary system take
place simultaneously, will, in the moving system, take place not
quite simultaneously; for the forward one will be somewhat behind
in time; and, second, all such motions will take place a little slower
than they did in the stationary system. The term electromagnetic

330 COMSTOCK— THE MODERN THEORY [April 22,

system, used in this sense, includes, of course, all radiant energy,
for it will be remembered that this type of energy is also electro-
magnetic.

Thus, on grounds of well-established electromagnetic theory and
without any new fundamental conceptions whatever, we can make
a general statement that any electromagnetic system, zvhen set in
motion, tends to assume a nezc state of equilibrium, and if this
change be allozced to take place, then all effects, electric and optical,
take place in the changed system in a manner exactly corresponding
to the cC'flv they did take place before the syston zvas set in motion.

A moment's thought will make it evident that we are here ap-
parently in the presence of a fundamental lack of harmony between
electromagnetic phenomena and the phenomena connected with
matter in general ; for, from the ordinary point of view, the parts of
a " rigid body " maintain their mutual relations unaltered whether
or not it is set in motion, while, as we have seen, this is not true of
electromagnetic systems.

Now, we have no choice but to consider a real body as a com-
bination made up of the two kinds of systems if there are two, the
electromagnetic type and the " rigid body " type ; hence it is clear
that, wdien such a mixed system is set in motion, there will be a
considerable amount of what we might term internal discord, owing
to the conflicting tendency of the two types. It would be very easy
to distinguish such a mixed moving system from the same system
at rest, because its parts would bear quite different relations to each
other than they did before. Setting a real system in motion would
be like heating an object made up of two substances having different
coefficients of expansion. The parts of such a system would then
bear totally dift'erent relations to each other than when the whole
thing was at rest, and the internal dissension would increase with
the velocity and would depend on its direction.

Now as a matter of fact, we all live on such a moving mixed
system, a system which is going around the sun with a velocity of
nearly twenty miles a second; and yet, although many carefully
planned and executed experiments have been carried out to detect
dift'erences in the actions of various electrical and optical systems,
according as thev are made to face with the earth's velocity or

I

191 1.] OF ELECTRICITY AND MATTER. 331

across it, every one of them has given negative results, and has
thus shown that the relative parts of the system hear the same rela-
tion to each other, no matter zvhat the direction of motion is.

It is like finding that an object made up of metal and glass had
no strains set up in it when heated, a result which could only be
attained if the metal and glass had the same coefficient of expansion.

What are we to conclude in the case before us? There seems
to be no alternative. \\'e already have seen that electrons are
among the fundamental constituents of all atoms ; we have seen that
radiant energy is electromagnetic and that such energy permeates all
matter. We have seen that energ}' resembles matter in possessing
mass, and that, therefore, to the same degree, matter resembles
energ}\ The necessary conclusion seems to be that all physical phe-
nomena obex the same general lazes of zehich the knozcn electro-
magnetic lazes are as yet the completest expression.

And now to what have we committed ourselves by this con-
clusion as regards changes due to motion? ^Merely this: that all
real systems being ultimately " electromagnetic " in the above sense,
undergo certain changes when set in motion, but these changes are
such as to leave all parts bearing the same relation to each other.
Thus since the knowledge of an observer travelling with the system
is only relative, he is not able to detect such absolute changes, just
as we are not able to detect the motion of the earth. The changes
in his svstem would be noticeable to an observer whose instruments
did not move, but cannot be detected by moving instruments.

The kind of change which wq have said is produced in a system
by setting it in motion has one property which is important and pro-
foundly significant. It, is that the moving observer sees precisely
the same change in stationary systems which he is passing as the
stationary observer sees in the moving system ; so that not only can
the moving observer not detect his motion by means of his instru-
ments, but the tzi'o obserz'ers together, if their memory fail, can by
no means tell which is moving. There is, in other words, a very
complete symmetry with regard to what the two observers can
actually find out about their systems, although we called one of them
stationary in the beginning.

Because of this complete symmetry the most conservative among

332 COMSTOCK— ELECTRICITY AND MATTER. [April 22,

us will admit that the concept of absolute motion need not be used
Z'ery often, at least, in the science of the future; if the foregoing-
views are true ones. The modern group of conceptions known as
the " Principle of Relativity " teaches that the idea of absolute
motion is entirely superfluous, and that the time honored concepts of
space and time, as independent of all motions, do not accurately fit
the real universe and should be modified.

^Modified in what way? Real time is measured by real clocks
and real distance is measured by real rigid bodies, and we find an
unexpected discord between moving clocks and stationary clocks,
and between moving rods and stationary ones. We have, therefore,
no possible use for what might be called " universal time." We
might form a vague concept of a " cosmic second " pervading the
universe, but we could do nothing with it, and it would therefore
be entirely artificial. Whenever we wished to think about an actual
moving object and wished to measure some vibration frequency on
it, let us say, we would have to use some actual clock-beat or other
periodic phenomenon as a unit. So that the actual universe has us
hopelessly in its grasp, and our concepts of space and time to be
valuable must be in harmony with the habits of real things.

The principle of relativity, therefore, makes changes in the
fundamental concepts of space and time for moving systems ; the
second in a moving system is longer, the meter, in the direction of
motion, shorter, than in stationary systems. The units then are in
harmony with real happenings in such systems, and this makes it
possible to introduce the last great synthesis of modern theory, the
deeper unity of physical law under the dominance of what we have
known as electromagnetic principles ; and this brings us one step
nearer to the last, ultimate generalization which is the unattainable
ideal of science.

Mas.sachusetts Institute of Technology,
April 20, 1911.

II.

RADIOACTIVITY.

Bv BERTRAM B. BOLTWOOD.
(Read April 22, igii.)

The study of the discharge of electricity through gases and the
properties of radioactive substances has done much to broaden our
knowledge of the relations of electricity and matter. It has served
to throw a new light on the ultimate constitution of matter itself,
and, while confirming the older theory of a discontinuous or atomic
structure, has led to the presumption that the chemical atom is not
only divisible into still smaller entities, but that in some cases it can
undergo a spontaneous disruption accompanied by the ejectment of
certain of its constituent parts at high velocities. All this has opened
a broad and attractive field for more or less legitimate speculation
and conjecture.

Since the first recognition by Becquerel in 1807 o^ the radio-
active phenomena exhibited by the element uranium, the extension of
our knowledge of the radioactive substances has steadily and pro-
gressively advanced. This development has been due in great part
to the early formulation of the theory of atomic disintegration, pro-
posed in 1902 by Rutherford and Soddy, which has served as a
systematic foundation and has afforded an orderly basis for the
interpretation of the otherwise somewhat complicated relations.

According to this hypothesis the atoms of the primary radioactive
elements are considered to undergo spontaneous disintegration and
in this manner to give rise to a series of successive radioactive prod-
ucts, differing from the parent substances as well as from one another
in phvsical and chemical properties and in the relative stability of
their atomic systems. Simultaneously with the disruption of the
atoms certain characteristic radiations are emitted by ikit systems,

333

334 BOLTWOOD— RADIOACTIVITY. [April 22,

and it is these radiations which led to the discovery of the radio-
elements and which particularly distinguishes them from all other
types of matter.

The characteristic radiations emitted by radioactive substances
are three in number and are known as the alpha, the beta and the
gamma rays.

For our knowledge of the alpha radiation we are indebted chiefly
to the work of Rutherford and his associates, which has shown con-
clusively that these rays consist of discreet particles of atomic dimen-
sions, projected with high velocities and bearing a positive charge.
The earlier investigations were conducted with a view to determin-
ing the mass of the particles from the deflections suffered by the
rays in electric and magnetic fields of known strengths. A value for
the ratio of the charge to the mass (c/iii) was obtained in this man-
ner and this led to the conclusion that, if the charge on a particle
was the same as that carried by the hydrogen ion in electrolysis, the
mass of the particles was approximately twice that of the hydrogen
atom. Strong evidence was also obtained that the alpha particles
emitted by the difi^erent radio-elements are identical in nature irre-
spective of the character of the particular radio-element from which
they originate.

A very ingenious experiment was then devised by Rutherford
and Geiger, in which a known fraction of the alpha particles emitted
by a radioactive source was allowed to enter a small ionization cham-
ber containing a gas at low pressure. Under the influence of a strong
electric field the ions formed by the entering particles acquired so
high a velocity that additional ions were produced by their collision
with neutral gas molecules and the electrical efifect was increased to
a point where the action of a single particle could be readily detected.
It was shown, moreover, that each of the scintillations appearing on
a screen of Sidot's blende placed in the path of the rays corresponded
to the impact of a single alpha particle.

In this manner the actual number of alpha particles emitted by a
radioactive substance was accurately counted, and it was found that
one gram of radium itself emitted 3.4 X 10^'' alpha particles per
second.

By measuring the electric charge imparted to an insulated plate

191 1.] BOLTWOOD— RADIOACTIVITY. 335

by the impact of a given number of alpha particles, the charge car-
ried by each particle could be readily determined. This was found
to be equal to 9.3 X lo"^'' electrostatic units. It was then shown in
an ingenious manner that this charge was twice that carried bv an
electron or by a hydrogen ion, although preceding determinations of
the latter magnitude had indicated that its value was somewhat less
than one half of 9.3 X io~^'^. The recent determinations made by Mil-
likam of the charge on an ion have shown, however, that 4.65 X iq-^"
is not far from correct and have confirmed the conclusion reached
by Rutherford and Geiger that the charge on an alpha particle is
equal to twice the unit charge of the hydrogen atom in electrolysis.

\\'ith this modification, the ratio of the charge to the mass of an
alpha particle indicates that the mass is equivalent to an atomic
weight of four. This corresponds to the mass of an atom of the
gaseous element helium.

The final proof of the intimate connection of the alpha particle
with the helium atom was supplied by Rutherford and Rovds who
proved by spectroscopic methods that readily detectible amounts of
helium could always be obtained when large numbers of alpha par-
ticles were allowed to penetrate through a thin glass wall into a
highly evacuated receptacle or into a screen of lead, from which the
helium was ultimately released by fusion of the metal.

It is a significant fact that although the alpha particles from the
different types of radioactive matter appear to be all of a similar
nature and to consist of atoms of helium bearing a double, positive
charge, the velocities at which they are ejected are dift'erent for the
dift'erent radioactive substances. The velocity of the particles emitted
by the atoms of any one type of matter undergoing transformation
is, however, always the same and is a characteristic constant for that
particular radio-element. Attention was first called to this impor-
tant relation by Bragg and Kleeman and it is undoubtedly significant
in its bearing on the constitution of the radio-atoms. The observed
velocities of the particles appear to lie between the limits of 1.5 X 10^
and 2.25 X 10^ centimeters per second.

Owing to their high velocities the alpha particles are capable of
passing through thin layers of ordinary matter, and can penetrate
into air at atmospheric pressure for distances of from somewhat less

336 BOLTWOOD— RADIOACTIVITY. [Apru 22,

than three to about eight centimeters. They produce phosphores-
cence and chemical action in substances on which they impinge and
strongly ionize gases through which they pass.

Through measurements of their detiection in electric and magnetic
fields the beta rays emitted by radioactive substances have been shown
to consist of negatively electrified particles or electrons with an
apparent mass about one eighteen-hundredth that of the hydrogen
atom. The velocity with which they are projected is considerably
higher than that of the alpha particles and in some cases exceeds nine
tenths the velocity of light. They are capable of penetrating through
moderate thicknesses of ordinary matter and for considerable dis-
tances in air. They cause phosphorescence and chemical action in
substances on which they fall and produce ions in gases through
which they pass.

Although the beta particles emitted by the difl:'erent t}pes of
radioactive matter are in all respects identical in nature, they exhibit
the same peculiarities with respect to the velocities with which they
are initially projected that has been observed in the case of the alpha
rays. The velocity of the beta rays from any given radio-element
is the same within certain limits for every disintegrating atom of that
element, but is difi:'erent from the velocity of the rays emitted by
other elements. The velocity of the beta rays is therefore charac-
teristic for each of the substances which give rise to this t}pe of
radiation and has undoubtedly a significant bearing on the constitu-
tion of the radio-atoms. It appears probable from some recent
experiments performed by Halin and von Be_\er, in which a magnetic
spectrum of the beta rays emitted by certain radioactive substances
was obtained, that the transformation of some of the radio-atoms is
accompanied by the expulsion of a series of beta particles of differ-
ent velocities. These results arc very suggestive of the model atom
devised by Sir J- J- Thomson in which the atom was assumed to be
built up of concentric shells of electrons revolving with different
velocities in circular orbits. It would seem quite possible that in
such a system a rearrangement of the parts might result in the expul-
sion of electrons from several layers simultaneously.

The third type of radiation associated with radioactive transfor-
mations, known as the gamma rays, is similar to the X-rays and is

I

191 1.] BOLTW'OOD— RADIOACTIVITY. 337

supposed to consist of electromagnetic pulses in the ether. A rather
ingenious corpuscular theory as to the nature of these rays has been
proposed by Bragg, but has not met with general acceptance owing
to the fact that it appears to be not altogether in accord with the
experimental evidence.

The origin of gamma rays seems to be very intimately connected
with the emission of beta particles, for the two types of radiation
have been observed to appear simultaneously and bear a certain defi-
nite relation to one another. A\'hen the expelled beta particle has a
high velocity the gamma ray is of a very penetrating character, while
if the velocity of the beta particle is low the gamma ray emitted has
but little power of penetrating ordinary matter.

The disintegration of the radio-elements takes place according
to a verv simple law and the number of atoms of any radio-element
which undergo transformation in the unit time is a definite propor-
tion of the total number of atoms initially present. The number
of atoms A' remaining unchanged after any time t is given by
A'^Xoc'^*, where No is the initial number of atoms and A is the
fraction undergoing transformation in the unit of time. This frac-
tion has a fixed and invariable value for each separate radio-element
and for this reason is known as the constant of cluing c for the ele-
ment in question. It is a relatively simple matter to determine the
period of time required under these conditions for exactly half of
any given quantity of a radio-element to be converted into other
substances and this time is known as tlic half zxiluc period. The
rate of change and the corresponding half value period is a definite
characteristic for each of the radio-elements but is very different for
the dift'erent radioactive substances. The half-value period of ura-
nium, for example, is over five billion years while the half-value
period of certain other radio-elements is only a few seconds.

Although the disintegration of some of the radio-elements has
been examined over wide extremes of temperature and pressure, and
under various other special conditions which would greatly influence
the course of ordinary chemical reactions, it has not been found pos-
sible to definitely alter or effect the rate at which transformation
takes place to the slightest measurable degree. It is therefore evident

PROC. AMER. PHTL. SOC., L. 200 V, PRINTED JULY 3I, I9II.

338 BOLTWOOD— RADIOACTIVITY. [April 22,

that the disintegration of the radio-active substances is of a wholly
different character from the ordinary chemical changes. This is
exactly what would be expected if the radioactive processes occur
within the atoms themselves, for, in accordance with our general
theories, chemical forces appear to be restricted in their action to the
exterior of the atomic systems only.

We have thus far considered only the laws which govern the
transformation of radioactive matter and the radiations which ac-
company the disintegration of the atoms ; let us now turn our atten-
tion to the substances themselves. Investigation has brought to light
three main groups of radioactive elements — the uranium series, the
thorium series and the alkali metals. Of the last mentioned our
knowledge is not very extensive. A type of beta radiation appears
to be emitted by the salts of potassium and rubidium but their title
to be considered as true radio-elements is not as yet entirely clear.

The uranium series, in addition to the parent substance, contains
ten products which may be properly considered as in the main line
of descent. These are uranium X, ionium, radium, radium emana-
tion, radium A, radium B, radium C, radium D, radium E and radium
F. Each of these products exhibits a characteristic chemical beha-
vior which is different from that of the parent element uranium. The
half value period of uranium has already been mentioned as exceed-
ing five billions of years and the disintegration of its atoms is accom-
panied by the expulsion of alpha particles. Uranium X, ionium and
radium are solids, the two first having chemical properties similar to
thorium, while radium has those of an alkali earth and particularly
resembles barium. Uranium X has a half value period of about
twenty-four days, and it emits only beta and gamma rays. The rate
of disintegration of ionium is not as yet know^n with any degree of
accuracy but it is certainly a relatively stable product and is trans-
formed but slowly. Its half value period is probably of the order of
ten thousand years. It emits alpha rays only. The half value period
of radium is approximately two thousand years. Rutherford and
Geiger have deduced a somewhat lower value, namely 1,760 years,
as a result of their experiments, but this value is probably an under
estimate, as w'ill be explained later in this paper. Radium emits
alpha rays and probably very low velocity beta rays also. The

191 1.] BOLTWOOD— RADIOACTIVITY. 339

change following radium is a striking one for the product in this case
is gaseous. It is known as the radium emanation and has the inert
chemical character of the rarer gases of the atmosphere, helium,
neon, argon, krypton and xenon. \\'hen the atoms of radium emana-
tion undergo transformation, the succeeding product known as ra-
dium A is formed. This is a solid and is deposited in the form of a
thin coating of active matter on the walls of a vessel containing the
emanation. This acquirement of activity by the surface of objects
in contact with the emanation was observed some time before a
satisfactory explanation of the phenomenon was suggested. It was
therefore known as "imparted" or "induced" activity. It is now
called the active deposit. Radium A, which has a half value period
of three minutes and emits alpha rays, is followed by radium B,
which emits beta rays and is half transformed in about twenty-six
minutes, and this in turn is succeeded by radium C with a half value
period of about nineteen minutes. The transformation of radium
C is accompanied by the expulsion of alpha, beta and gamma rays.
An interesting product known as radium D then ensues, its transfor-
mation being characterized by the absence of any detectible radiation
whatever. A product of this sort is known as a rayless change and
other examples to such a change occur in both the thorium and
actinium series. On account of the similarity of its chemical prop-
erties to those of ordinary lead, radium D is known as radio-lead.
It undergoes transformation more slowly than the immediately pre-
ceding products and has a half value period of about sixteen years.
It is followed by radium E, a beta ray change, with a period of five
days, and this is succeeded by radium F, otherwise known as polo-
nium. Polonium emits alpha rays only and is half transformed in
one hundred and forty-three days.

In addition to the ionium-radium series, uranium is also the pro-
genitor of another group of radio-elements of which actinium is the
first and most stable member. The rate of change of actinium has
not yet been determined, but is comparatively slow and is probably
of the same order as that of the radium. Actinium offers another
example of the rayless changes which have already been referred
to, and no radiations have been observed to accompany its trans-
formation.

340 BOLTWOOD— RADIOACTIVITY. [April 22,

Six products subsequent to actinium have thus far been identi-
fied in this series. The first is radioactiniuni, an element having a
half-value period of 19^ days and emitting both alpha and beta par-
ticles. The subsequent product is known as actinium X. The half
value period of actinium X is about ten days and its atoms disin-
tegrate with the expulsion of alpha particles. The next step in the
series of transformation is the gaseous product known as the actin-
ium emanation. This, like the radium emanation, is chemically inert
and incapable of entering into combination with other elements.
Actinium emanation is a very short lived substance and has a half
value period of only 3.9 seconds. It is transformed successively
into three other products, which are solids, known respectively as
actinium A, B and C, and together constitute the so-called active
deposit from the actinium emanation. Actinium A has a half value
period of 36 minutes, actinium V> of 3.1 minutes and actinium C of
5.1 minutes. The first emits beta rays, the second alpha rays, and
the third beta and gamma rays.

As already stated, actinium and its products are genetically con-
nected with uranium and are. in some manner as yet obscure, derived
from it. The evidence in support of this conclusion is quite con-
vincing. All uranium minerals contain definite quantities of actin-
ium and in the older minerals the relative proportions of uranium
and actinium present arc so constant as to permit of no other expla-
nation. But the actual genealogical history of actinium is still
obscure and we are not yet in a position to clearly trace the line of
descent. Whether actinium is formed directly from uranium by a
special kind of transformation which involves only a small propor-
tion of the total number of the atoms changing, or whether its pro-
duction occurs at a later stage in the uranium-radium series, is at
present an open question and the discovery of the true relations is
one of the most interesting problems now awaiting solution.

The thorium series presents another group of radio-elements
comprising ten successive members. I shall not stop to enumerate
these in detail, but their princi])al phy>ical and chemical charactei-
istics have already been determined. Thorium itself, the parent sub-
stance, has a verv slow rate of change, which is probably not more
than a fifth that of uranium.

191 1] BOLTWOOD— RADIOACTIVITY. 341

Its first product, mesothorium i. is another example of a rayless
change Hke radium D and actinium. Owing to the fact that large
quantities of monazite are commercially treated for the extraction
of thorium used in the manufacture of incandescent gas mantles and
that the technical separation and isolation of mesothorium appears
to be an economic possibility, there is some prospect that mesothorium
may become a competitor of radium for scientific and therapeutic
uses. Its life compared with radium is relatively short, however,
its half value period being 5^ years, but this in itself is not neces-
sarily a serious disadvantage. The chemical properties of meso-
thorium are similar to those of radium and barium.

The fifth product in the thorium series is known as the thorium
emanation and is a chemically inert gas like the raditmi and actinium
emanations. The remaining four products constitute the tJwriiiiii
actk'c deposit.

The combined uranium and thorium series includes 28 radio-
elements, of which only the two parent elements were known before
the development of radioactive methods. Radioactivity has there-
fore added a considerable quota to the known types of matter.

An interesting relation which is met in the study of radioactive
change is the so-called radioacfiz'c equilibrium. If a relatively long-
lived radio-element A is the parent of a less stable product B, and
if A is initially entirely freed from B, then a certain definite fraction
of the atoms of A will undergo transformation each second to form
atoms of the product B. The number of atoms of B produced from
A in this manner each second will be essentially constant and the
amount of B will increase. But the atoms of B also undergo trans-
formation at a constant rate and, as the C|uantity of B increases, a
continually increasing number of its atoms will be transformed in
the unit of time. A point will finally be reached where the number
of atoms of B which disintegrate in any given time will be exactly
equal to the number of atoms of B formed from A in the same
interval. The relative amounts of A and B will then remain con-
stant and the conditions can be expressed by the equation

where P is the number of atoms of A and A^ its constant of change,

342 BOLTWOOD— RADIOACTIVITY. [April 22,

and Q is the number of atoms of B and A. the constant of change of
the product B. Under these conditions the substances A and B are
said to be in equilibritim with one another. The general mathemat-
ical theory of successive changes of this kind has been developed by
Rutherford.

In the discussion of the characteristics of the alpha rays it has
been pointed out that the evidence supplied by the determination of
the ratio of the charge to the mass of these particles indicates that
their nature is the same in all cases. Let us consider briefly the
additional facts which are in support of this conclusion.

The presence of considerable proportions of helium in crystalline
minerals containing m-anium and thorium has been very frequently
noticed. It was found by Ramsay and Soddy in 1903 that helium
could be detected in the residual gas set free when a specimen of
crystalline radium bromide was dissolved in water, and shortly after
this they showed that the spectrum of helium appeared with time in
a tube which initially contained only radium emanation. Debierne
found that helium was produced by a strong preparation of actinium,
and conclusive proof has also been obtained by Strutt and by Soddy
that helium results from the disintegration of both thorium and
uranium.

During the past year I was able to experimentally demonstrate
the production of helium by ionium, and some earlier experiments
carried out by Professor Rutherford and myself showed that helium
appeared during the disintegration of polonium also. The latter
conclusion has since been confirmed b_\- the work of Mme. Curie and
Debierne.

The data supphed by the counting experiments of Rutherford
and Geiger afford a basis for the calculation of a number of impor-
tant physical (luantitics, such as the mass of the hydrogen atom, the
number of atoms in one gram of h_\dr()gen and the number of mole-
cules per cubic centimeter of any gas at standard pressure and tem-
perature. In a similar matter Rutherford and Geiger have calcu-
lated the amount of helium produced per }ear by one gram of radium
containing equilibrium amounts of its three alpha ray products, the
emanation, radium A and radium C. The number obtained in this
way was 158 cubic millimeters of helium per year per gram of

I9II-] BOLTWOOD— RADIOACTIVITY. 343

radium. ^Measurements of the rate of production of helium by a
radium salt have been carried out by Sir James Dewar and have
given results somewhat in excess of this, namely 182 and 169 cubic
millimeters. As a confirmation of the accuracy of Rutherford and
Geiger's values, however, it may be stated that an investigation of
the production of helium by radium made last year by Professor
Rutherford and myself gave results in excellent agreement with the
calculated value. An account of these experiments will be published
shortly.

In connection with these results there is, however, one rather
important point which should be mentioned. This is the fact that
tne rate of production of helium and the half value period of radium
as calculated by Rutherford and Geiger from the results of their
counting experiments, are directly dependent of the purity of the
salt of radium used as a standard in their measurements. They
assumed that the material of their radium standard was pure anhy-
drous radium bromide containing 58.5 per cent, of radium. If this
was not the case and the material used as their standard contains
less than the theoretical amount of radium, their calculation of the
number of alpha particles emitted per gram of radium and the rate
of production of helium is too low, and their estimate of the half
value period of radium is too high. If, on the other hand, the mate-
rial of their standard consists in part of some other compound of
radium containing a higher proportion of this element than is con-
tained in the bromide, their value for the number of alpha particles
emitted and the rate of production of helium is too high and their
calculated rate of disintegration of radium is too low.

There are certain reasons which lead me to believe that the
radium standard used by Rutherford and Geiger actually contains a
higher proportion of the element radium than they have assumed in
their calculation, and that the true half value period of radium is
greater than 1,760 years as they have deduced it. In 1908 I pub-
lished an account of some experiments on the growth of radium in
ionium preparations, which pointed to two thousand years as the
half-value period of the former. This estimate was quite indepen-
dent of any radium standard and I am of the opinion that it is nearer
the true value than is the estimate made by Rutherford and Geiger.

344 BOLTW'OOD— RADIOACTIVITY. [April 22,

The point can be definitely settled, however, by a comparison of
Rutherford's standard with a standard of indisputable purity. Such
a standard is in prospect in the not distant future and its prepara-
tion has been undertaken by ]Mme. Curie on behalf of the Interna-
tional Radium Standards Committee appointed at the recent Radio-
logical Congress in Brussels.

A very interesting action which has been observed to accompany
radioactive transformations is known as the recoil plicnouicnon.
When a plate bearing a thin layer of very active material is placed
in close proximity of another plate which is inactive, a portion of
the active matter becomes detached from the film and is deposited on
the surface of the second plate.

The efifect is increased considerably if the receiving plate is
charged negatively with respect to the plate bearing the active coat-
ing. This action is apparently due to the fact that, when the alpha
or beta rays are expelled at a high velocity from a radio-atom under-
going transformation, the reaction on the residual atom causes this
to move in the opposite direction with sufficient force to detach it
from the plate. The action is analogous to the recoil of a rifle
attending the expulsion of a high velocity bullet. When, for exam-
ple, the active coating on the first plate consists of radium A then
the active matter received on the second plate is composed almost
exclusively of radium B ; and when the film consists of radium B the
material thrown ofif is for the most part radium C. This and other
similar effects which have been noted are all of such a nature as to
suggest that the explanation proposed for this interesting phenom-
enon is the correct one. The effect of the electric field indicates that
in some way these " rest atoms " acquire positive electric charges.

From the standpoint of the disintegration theory, it is evident,
when we consider the three principal grouj^s of radioactive sub-
stances, the uranium-radium group, the actinium group, and the
thorium group, that the radioactive phenomena exhibited by the
atoms abruptly disappear after they have passed through a certain
series of transformations, which terminates with radium F in one
instance, with actinium C in another and with thorium D in the
third. The apparent explanation of this circumstance would seem
to be, that, following the last active change, the residual atomic

191 1-] BOLTWOOD— RADIOACTIVITY. 345

nucleus finally attains a permanently stable form which undergoes
no further alterations. If such is indeed the case, then we might
expect that these ultimate end products of radioactive decay would
accumulate in old radioactive minerals where the process of trans-
formation has been proceeding for long geological periods. This
line of reasoning has enabled us to identify at least one of these
products and that is, in all probability, the one following radium F.
The residual atom in this case appears to be no other than the atom
of ordinary lead. There are, moreover, certain theoretical argu-
ments which point to the same conclusion. The accepted atomic
weight of uranium is 238.5. It has been found that two alpha par-
ticles are emitted during its transformation and one by the succeed-
ing product, ionium. This would correspond to the loss of three
alpha particles or helium atoms with an atomic weight of four or a
total of twelve units. Two hundred and thirty-eight and one half
less twelve give two hundred and twenty-six and one half for the
atomic weight of radium, which corresponds to the value obtained
in the actual determination of the atomic weight of this element
by ]\Ime. Curie. The transformations of the atoms of radium, the
emanation, radium A, radium C and radium F are each accompanied
by the expulsion of another alpha particle, making five in all. Five
times four is twenty and two hundred and twenty-six and one half
less twenty is two hundred and six and one half. The latter number
is sufficiently near to two hundred and seven and one tenth, the most
recently determined atomic weight of lead, to support the conclusion
that lead is the ultimate disintegration product of radium. It has
not yet been possible to determine the end products of the actinium
or the thorium series but they will undoubtedly be identified among
the various elements occurring in small proportions in the older ura-
nium and thorium minerals.

Before completing this necessarily brief resume of the present
status of the study of radioactive phenomena it is necessary to make
some reference to the series of papers published by Sir William
Ramsay associated with A. T. Cameron and F. L. Usher. These
papers, which deal with the action of radium emanation on various
other substances, suggest the occurrence of certain changes, which
if they really took place would be of fundamental importance to the

346 BOLTWOOD— RADIOACTIVITY. [April 22.

theory of the constitution of matter. Unfortunately, so Httle weight
can be attached to these results and the conclusions reached by these
authors, that they have received no serious consideration from those
most competent to judge their value.

In closing, a point which seems worthy of special emphasis may
be briefly mentioned. This is the apparently important part played
by the alpha or material particle emitted during radioactive trans-
formations. In those cases where it has been possible to observe
its influence, the loss of an alpha particle is always accompanied by
a corresponding decrease in the mass of the atom from which it is
separated. Although the disruption of a radio-atom is accompanied
bv the release of a relatively enormous amount of energy, still it
appears that the fragments projected into space are always of one
or the other of two quite distinct classes; either beta particles of
extremelv small mass, or helium atoms of a mass seven thousand
times that of the beta particles. So far as the results of our experi-
ments have enlightened us we have not yet been able to observe the
resolving of the by far the greater proportion of the effective mass of
an atom into anything other than a further subdivision of ordinary
matter.

Yale University,
April 22, 1911.

III.

THE DYNAMICAL EFFECTS OF AGGREGATES OF
ELECTRONS.

By OWEN W. RICHARDSON.
(Read April 22, 1911.)

I. Electrons and Matter.

The enormous difference in tlie behavior of dift'erent materials
towards electric force is a matter with which everyone is familiar ;
and it is one of the triumphs of the electron theory that it has given
us a verv satisfactory picture of the dift'erence between insulators
and conductors of electricity. We are to regard all matter as made
up primarily out of electrons. They are the stones with which the
material structure is built up, the electrodynamic forces are the
cement which holds the stones together. There are, however, two
different ways in which the electrons may exist in a given portion
of matter. They may be located in position of stable equilibrium,
in which case a very small force will displace them to a small extent
but a perfectly enormous force would be required to dislodge them
thoroughly and give rise to instability ; or they may be so loosely
held that they are able to move about in the interstices of the material,
very much after the fashion in which we believe the molecules move
about in a gas. In the former case, when the electrons are practically
fixed, we say the substance is an insulator ; in the latter case, where
they are wandering about, the substance is a conductor.

A moment's reflection will show that this dift'erence is sufficient
to explain the difference between insulators and conductors. Con-
sider what happens when a slab of the first kind is placed in an
electric field. There will be a displacement of the electrons, it is
true, but the displacement will be small and they will all return to
their original equilibrium positions as soon as the external field is

347

348 RICHARDSON— DYNAMICAL EFFECTS OF [April 22,

removed. There will be no transportation of electrons and that is
what, on the electron theory, constitutes an electric current. The
electric field across the slab is, nevertheless, dift'erent from what
it would be if the material were not present. The difference be-
tween dift'erent insulating materials in this respect depends solely
on the comparative ease of displacement of the electrons they con-
tain. The specific inductive capacity of dielectrics, which, you will
remember, was discovered by Cavendish and Faraday, is, in fact, a
measure of the product of the number of electrons in unit volume
of the material b_\- the average displacement which they undergo in
unit field.

The behavior of the second kind of material is quite dift'erent.
Even in the absence of the electric field, the so-called free electrons
are moving about in it in an irregular manner in all directions. The
effect of an external field is to superpose on the irregular motion a
definite drift, on the average, in the direction of the current. This
drift of the electrons involves traiisportafion of electricity and there-
fore implies the existence of an electric current.

All the laws which regulate the transference of electricity across
conductors, such as, for example, Ohm's Law, which states that the
current is proportional to the applied electromotive force, and Joule's
Law, which states that the rate of production of heat by a current
is equal to the product of the resistance of the circuit by the square
of the current, follow at once from this simple hypothesis. It is not
necessary to suppose that all the electrons in the material are present
in the free condition ; some of them may be, and in all probability
the majority are, in a state of equilibrium similar to that which occurs
in insulators. All that is necessary is that some of the electrons
should be able to move without restraint. When the other conditions
are the same the magnitude of the current which a given material
will transport is proportional to the number of carriers available;
that is, to the number of free electrons per unit volume.

It is in the explanation of the relation between the conductivity
of substances for electricit}- and for heat that the electron theory
has scored one of its most notable triumphs. Everybody knows that
the best conductors for electricity are also the best conductors for
heat. It is not so generally known how very close the relationship

I9II.]

AGGREGATES OF ELECTRONS.

349

between the two phenomena is.
columns of figures are shown.

In the accompanying table two

Material.

Copper, commercial

Copper (T) pure

Copper (2) pure

Silver, pure

Gold (I)

Gold ( 2) pure

Nickel

Zinc ( i)

Zinc (2) pure

Cadmium, pure

Lead, pure

Tin. pure

Aluminium

Platinum (i)

Platinum (2 ) pure

Palladium

I ron ( I )

Iron (2)

Steel

Bismuth

Constantan (6oCu, 40Ni) ...
Manganin (84CU, 4Ni, i2Mn) .

Ratio: Thermal Conductivity,
Electrical Conductivity.

at 18° C.

6.76 X
6.6s X

6.71 X
6.86 X
7.27 X
7-09 X
6.99 X
7-05 X

6.72 X
7.06 X

7.15 X

7-35 X
6.36 X

7.76 X

7-53 X

7.54 X

8.02 X
8.38 X
9-03 X
9.64 X
11.06 X

9.14 X

at 18° C.

at 18° C.

at 18° C.

at 18° C.

at 18° C.

at 18" C.

at 18° C.

at 18° C.

at 18° C.

at 18° C.

at 18° C.

at 18° C.

at 18° C.

at 18° C.

at 18° C.

at 18° C.

at 18° C.

o'" at 18° C.

o^" at 18° C.

0'" at 18° C.

o"' at 18" C.

Temperature

Coefficient of

this Ratio,

Per Cent.

They represent the results of measurements by Jaeger and Dies-
selhorst of the electric and thermal conductivities of a large number
of metals and alloys. The first column of figures gives the ratio of
the thermal to the electrical conductivitv for each of these substances
and the second gives the percentage change of this ratio when the
temperature is increased one degree. It will at once be noticed that
the numbers in each column are almost equal, particularly if we
keep to the pure metals. Thus for every pure metal the electrical
conductivity bears to the thermal conductivit}- a proportion which is
almost independent of the metal : and the ratio of the thermal con-
ductivity to the electrical conductivity increases by almost the same
amount for one degree rise of temperature for each metal. The
coefficient of increase of this ratio with increase of temperature is
also very nearly equal to the coefficient of increase of the volume of all
gases with temperature, when the pressure is maintained constant.

350 RICHARDSON— DYNAMICAL EFFECTS OF [April 22,

These interesting relations were shown to be a consequence of the
electron theory of conductors by Drude. He proved that they fol-
low inevitably from the assumptions ( i ) that a metal contains
electrons which move about freely like the molecules of a gas, (2)
that they possess a certain average mean length of free path \
during the traversing of which they are only acted on by the
external applied electric force, (3) that this path is terminated by
a collision and that the new motion which then ensues is, on the
average, independent of the previous motion ; and lastly (4) that
their average kinetic energy is the same as the average kinetic
energy of translation of a molecule of any gas at the same tempera-
tur as the metal.

A simplified form of Drude's deduction may be given here. If
X is the electric intensity inside the metal, c the electric charge pos-
sessed by an electron and i;?. its mass, then the force acting on the
electron during its free path is Xc and its acceleration Xe/ni. If
the velocitv of the particle at the beginning of the path is n its

velocitv at the end will be ?/ -|- — / where t is the average time be-

tween two collisions. The average velocity in the direction of the

I ^
electric field is therefore -X—/ since the average value of n taken

over a large number of electrons is zero. Now the free path A is
equal to vt where i' is the mean speed. Thus the average drift
velocity of the electrons in the direction of the electric field may be

1 ^ ^' ^

written in the form X . If 11 is the number of electrons in

2 jn V

unit volume, the number of them which, in unit time, drift across a
unit area drawn perpendicular to the direction of the electric force

1 ^ e \

X will be - nX . Each of these carries a charge c so that the

2 m V

quantity of electricity transported across unit area, or in other words,
the electric current densit\- will be

2 ;// V
Now it is a necessar}' consequence of the principles which under-
lie the kinetic theory of matter that \mv- should be equal to nB where
B is the absolute temperature and ot is a universal constant which may

'9II-] AGGREGATES OF ELECTRONS. 351

be calculated from the properties of gases. This assertion is the
mathematical statement of the relation (4) enumerated above.
Making this substitution we find that the specific electrical conduc-

/ /irX7'
tivitv of the material is cr = -y = - ^ . In this formula c- and a

A 4^6/

have the same value for all substances, u and A are constants charac-
teristic of each substance, z' is independent of the nature of the
material but is proportional to the square root of the absolute
temperature.

It is a well-known result of experiment that the specific conduc-
tivity of all substances is inversely proportional to the absolute tem-
perature. We therefore conclude that the product ;/A for all metals
must be inversely proportional to the square root of the absolute
temperature.

It is a well-known result of the kinetic theory of gases that the

thermal conductivitv of a gas is equal to iiiXz'a. Hence — = —6.

Thus this ratio should have the same value for all metals at the
same temperature and the temperature variation should be the same
as that of the volume of a gas at constant pressure. These are the
relations which are exhibited by the experimental results of Jaeger
and Diesselherst.

The electron theory of metallic conduction has enabled us to
understand a number of curious effects which occur when a con-
ductor is placed in a magnetic field. One of these, the Hall effect,
consists in a deflection of the line of flow of a current which is
caused by the magnetic field. Another effect, which is especially
marked in the case of Bismuth, is an alteration of the specific resist-
ance of the material caused by a magnetic field. These eifects are
intimately connected together and have a simple explanation on the
electron theory. It is well known that any electrified particle moving
in a magnetic field is acted on by a force which is perpendicular to
the plane containing the magnetic force and the direction of motion.
The superposition of this force upon the other forces acting on the
electrons in a metal carrying a current will cause all the electrons to
curve round in the same general direction, giving rise to the Hall
eifect. It will also increase the average curvature of the paths of the

352 RICHARDSON— DYNAMICAL EFFECTS OF [Apni 22,

electrons. In this wa}^ the time which is required for electricity to be
transferred will be greater so that the specific electrical conductivity
will be diminished. This is the explanation of the second effect.
Both these effects are complicated by the action of the electrons on
the atoms so that the foregoing description is only to be regarded
as a rough outline of what really occurs.

So far we have only considered the wa}' in which the electron
theory of conduction explains a number of phenomena which were
familiar before it was enunciated. The power to do this is a neces-
sary attribute of every scientific theory. A scientific theory, how-
ever, is often much more useful than this in that it leads to the pre-
diction of phenomena which would hardly have been foreseen without
its aid. The present theory has been able to prove its usefulness in
this way. as the principles underlying it have enabled us to develop
a new chapter in physical science, a chapter to which I have ventured
to give the name of Thermionics. Thermionics relates to the emis-
sion of electrified particles by hot bodies and the phenomena to which
they give rise.

It is found that all bodies when heated to a sufficiently high tem-
perature give rise to an emission of both negatively and positively
charged particles. In many ways the negative emission is the more
interesting as the particles emitted are negative electrons having prop-
erties identical with those of the carriers of the cathode rays. The
connection between this emission of negative electrons and the trans-
portation of electricity in a metallic conductor is very intimate. We
have seen that, in order to explain the phenomena exhibited by me-
tallic conduction, it is necessary to suppose that such conductors
contain large numbers of "free" electrons. If these electrons are
maving about freely inside the conductor, as we have supposed, the
question at once arises as to why they do not escape into the sur-
rounding atmosphere. It is clear that they do not do so, otherwise
there would be a leakage of electricity from the surface of all con-
ductors at ordinary temperatures. The answer must be that there
are forces at the surface of the metal which are sufficiently great to
prevent them from escaping. Now consider what we should ex-
pect to happen as the temperature of such a body is raised. We have
supposed that the average kinetic energy of the contained electrons

191 1.] AGGREGATES OF ELECTRONS. 353

is higher the higher the temperature. Clearly, at a sufficiently high
temperature some of the particles will have enough energy from their
heat motion to be able to break through the surface. Aloreover, the
number which are able to escape will be greater the higher the
temperature.

A theory following these lines has succeeded in predicting the
way in which the emission of the electrons depends upon the tem-
perature as well as a number of other interesting relations between
the thermal and electrical behavior of substances. It will be re-
marked that the view which has been outlined is very similar to the
view of the phenomenon of evaporation which is afforded by the
kinetic theory of matter. According to that theory the particles of
the liquid escape into the vapor when their kinetic energy (to be
accurate we ought to say that part of it which depends on the com-
ponent of velocity normal to the surface) exceeds the work they
have to do in order to pass through the surface. Thermionic emis-
sion may be looked upon then simply as the evaporation of electrons
which may be regarded as dissolved in the metal. Just as water is
cooled when it evaporates and heated when steam condenses into it;
so we should expect a conductor to be cooled when it emits electrons
and heated when it absorbs them. Both these effects have recently
been discovered, the former by W'ehnelt and Jentzsch and the latter
by Richardson and Cook.

There is one point in this connection which is worthy of further
consideration. We have seen that it is necessary to suppose that
the electrons in a metal behave like the molecules of a gas. The
same will be at least as true of them after they have been emitted.
Thus when a metal at a high temperature lies in an air-tight en-
closure there will be two atmospheres of electrons, one at a high
pressure inside the metal and the other at a low pressure in the
enclosure outside of the metal. If the principles of the kinetic
theory of matter are well grounded it can be shown that in both of
these atmospheres the electrons are moving about with all possible
speeds but that the proportion of them which have a given speed is
the same for each atmosphere. Moreover, the proportion is the same
known function of the temperature in each case and in each case also

PROG. AMER. PHIL. SOC, L. 200 \V, PRINTED AUG. 4, I9II.

354 RICHARDSON— DYNAMICAL EFFECTS OF [April 22,

the average kinetic energy should be the same as the average kinetic
energy of a molecule of any gas at the temperature of the enclosure.
In fact the laws of the kinetic theory of gases can be applied
without change to the atmospheres of electrons ; and the above asser-
tions are simply statements of a theorem in the kinetic theory of
gases called, after its discoverers, the Maxwell-Boltzmann Law.
According to this law if a large number of molecules are selected
at random out of any gas the proportion of them which have speeds
lying between certain assigned values let us say // and u' is a certain
definite function of n and u'. The value of this function, which in
addition to it and u' depends only upon the temperature of the gas
and the mass of its molecules, was first deduced by Maxwell. Max-
well's deduction of the value of this function, though sufficiently con-
vincing to those who are familiar with the methods of mathematical
physics, was, neverthless, a highly abstract piece of reasoning; and
it has been impossible up to the present to make anything in the
nature of a direct test of it by experiment on gases. With the
atmospheres of electrons we are, however, able to do a great deal
more than we could with a gas made up of uncharged molecules. By
placing them in a suitable electric field we can bring forces to bear
on each individual electron which are enormous compared with the
forces exerted on a molecule by the earth's gravitational field. For
example if the electrons are being emitted from a heated flat plate
we can place another flat surface a little in front and charge it up,
so that the electric field tends to drive the ions back into the surface
at which they originated. Under these circumstances only those
electrons will be able to cross from one plate to the other if their
kinetic energy is greater than a certain value depending on the elec-
tric field between the plates ; thus the current that gets across will be
a measure of the number of electrons emitted whose kinetic energy
exceeds a known value. By experiments of this kind, and others
based on similar principles, we have succeeded in determining the
law of distribution of speed among the individual electrons which
are emitted. It is found to agree in every particular with that pre-
dicted by ^Maxwell for the case of a gas whose temperature is the
same as that of the metal emitting the electrons and whose molecular
weight is equal to the mass of an electron. In particular the average

19II.] AGGREGATES OF ELECTRONS. 355

kinetic energy of the electrons is the same as that of the molecules
of a gas at the temperature of the metal which emits them ; and we
can calculate the value of the well-known constant R in the gas
equation pi'=^R$, where p is the pressure, z' the volume and 6 the
absolute temperature of the gas, from purely electrical experiments
of the kind indicated. It follows from the results of these experiments
together with a simple application of the principles of the dynamical
theory of gases that the free electrons inside a metal must have the
distribution of velocity which is required by Maxwell's law and in
particular must have the same average translational kinetic energy
as the molecules of a gas at the temperature of the metal which
contains them.

2. Material Media axd Electromagnetic Radiations.

The action of light on insulating media is a rather complicated,
but extremely important, phenomenon on which the electron theory
has thrown a great deal of light. IMaxwell showed, many years ago,
that light is an electromagnetic phenomenon. A beam of light is in
fact a wave of oscillating electric and magnetic force, the electric
and magnetic forces being at right angles to one another and to the
direction of propagation. \Mien such a wave falls on an insulating
medium the oscillating electric force will set into vibration the com-
paratively stable electrons which, as we have seen, are embedded in
the medium. The electrons will execute what are appropriately
called forced oscillations, about their original equilibrium positions,
and these oscillations will have the same periodic time as the light.
Thus when it traverses a material insulating medium the light has
not only to keep itself going; it has to keep the electrons which make
up the medium going as well. Roughly speaking one may say that
the electrons in such a medium behave like a load on the luminif-
erous ether. We should therefore expect them to diminish the
speed of propagation of light through it and this is found to be
the case. The exact expression for the velocity cannot be obtained
without going more deeply than we have time to into the electro-
magnetic theory of light. It w'as first given by Maxwell, who
showed that the refractive index, to which the velocity of propaga-
tion is inversely proportional, was equal to the square root of the

356 RICHARDSON— DYNAMICAL EFFECTS OF [April 22,

effective specific inductive capacity of the medium. Xow the spe-
cific inductive capacity of an insulating medium is equal to unity
plus the product of the numl^cr of electrons per unit volume by
their average displacement in unit electric field. When the material
is subjected to constant electric forces the displacements of the elec-
trons are always proportional to the forces and the specific inductive
capacity is therefore a constant quantity. When the force is an
oscillating one the matter is complicated by the fact that the elec-
trons try, as it were, to strike a balance between their own natural
period of oscillation and that of the force acting on them. They
end by oscillating with the same frequency as the force which
excites them but the distance thev travel from their e(iuilibrium
position depends a good deal on their natural periods as well. Thus
the specific inductive capacity for oscillating forces will not be a
constant quantity b'ut will depend to some extent on the frequency
of oscillation of the force. By the effective specific inductive ca-
pacity we mean the specific inductive capacity for electric forces
which oscillate with the frequency of the light under consideration.

It is evident from what has been said that the refractive index
of an insulating substance depends upon the frequency or, in other
words, upon the color of the light. W^e see at once why a beam of
white light is split up by a prism into the constituent spectral colors.
For each ray is deviated by the prism according to the value of its
refractive index.

Perhaps the most interesting question in this part of our subject
is that of the behavior of a substance towards light whose frequency
is close to that of the natural periods of the substance. In that case
the electrons are set into violent motion owing to the occurrence of
what are sometimes called sympathetic vibrations. The nature of
this phenomenon may best be illustrated by considering a simple
mechanical analogy. Imagine a spiral wire with a weight at one
end to be hung from a shaking support. If the weight is pulled
down and let go it will oscillate backwards and forwards with a
definite natural freffucncy which depends on the stift'ness of the
spring and the heaviness of the weight. If the shakiness of the
support arises from tremors in the building, to the walls of which we
will suppose it bolted, as a rule the frequency of its vibrations will

191 1.] AGGREGATES OF ELECTRONS. 357

be very great compared with the natural frequency of the spring.
In that case the shakiness of the support will have very little effect
on the spring. If however the frequency of the tremors happens to
be equal or nearly equal to the natural frequency of the spring the
latter is set into very violent agitation, for the reason that the
natural swings of the spring are continually being helped by the
oscillations of the support.

A precisely analogous eft'ect takes place when the period of the
light is close to the natural period of the electrons. In fact it can
be shown that, if there is nothing analogous to a frictional force to
damp down the vibrations of the electrons, they will execute oscilla-
tions of infinite amplitude when there is exact coincidence between
the periods. Since the displacement of the electrons in unit electric
field is the important factor in determining the refractive index we
should expect its value to change very considerably in this region.
As a matter of fact, in the extreme case where there is no damping,
the value of ^- falls rapidly from a small positive quantity on the
short wave-length side of the position of coincidence to the value
— oc at exact coincidence (A = Ao). As the period of exact coinci-
dence is passed ix- changes suddenly to -f- x and on the long wave-
length side falls rapidly to a rather larger positive value than the
one that it had at a great distance from the natural period on the
short wave-length side.

Several very important deductions can be drawn from the results
which have just been described. In the first place we notice that
provided we always keep to the same side of the natural period, no
matter which side we choose, then the refractive index jj. always
diminishes as the wave-length A increases. Hence, since the devia-
tion of light by a prism is greater when the refractive index is
greater it will be smaller the greater the wave-length. The blue
light will therefore be deviated more than the red light in the spec-
trum. This is the well known kind of dispersion which is exhibited
by prisms of glass and similar colorless transparent substances.

When part of the spectrum lies on one side of the natural period
and part on the other there is a sudden increase in the value of the
refractive index when the natural period is crossed. The spec-
trum will then consist of two groups of colors, that on the long

358 RICHARDSON— DYNAMICAL EFFECTS OF [April 22,

wave-length side being more deviated than that on the short wave-
length side, although in each group the colors are in the normal
order. This is the so-called anomalous dispersion which was dis-
covered by Kundt and which is exhibited by all transparent colored
bodies, like the aniline dyes, wdiich possess a metallic shimmer.
Immediately on the short wave-length side of A,,, we have seen that
/u,- has a negative value in the case we are contemplating, /x in this
region has therefore what mathematicians call an imaginary value.
It can be shown that this imaginary value means that the waves are
incapable of entering the medium. When a train of waves of this
wave-length falls on the medumi they are not absorbed, properly
speaking, but are completely reflected. The substance would appear
to be opaque to light of this wave-length not because it absorbs the
light which falls on it but because it reflects it completely. If
mixed light which contained some of this particular wave-length
were made to undergo a sufficient number of successive reflections
from plates of the substance, only light of this particular region of
frequency would ultimately be left over, since a certain percentage
of the other wave-lengths always gets through. This principle has
been utilised by Rubens to isolate radiations of definite wave-length
in the infra-red part of the spectrum. These radiations are called,
very appropriately, residual rays.

The foregoing discussion does not touch the very interesting
questions of the absorption of light by insulating media. There will
be no absorption, properly speaking, unless there are forces acting
on the moving electrons which tend to dissipate the energy of the
light. Such forces must in general exist and it is usually assumed
that there is a retarding force proportional to the velocity of the
moving electrons, chiefly because this is the simplest assumption
wdiich can be made which is not in contradiction with fact. The
existence of forces of this kind modifies the foregoing conclusions
to a considerable extent in detail but it does not afl^ect their general
character.

Planck has pointed out that it follows from the principles of the
electromagnetic theory of light that the radiation from the moving
electrons gives rise to a retarding force which may be taken to be
proportional to their velocity. Such a force must un(|uestionably

'91 ^J AGGREGATES OF ELECTRONS. 359

exist but its magnitude is quite small. It is of interest to see if it
is sufficiently large to account for the known cases in which the
dissipation of energy is smallest. These are unquestionly the cases
in which residual rays are obtained. I have developed a formula
which expresses the percentage of incident energy which goes into
the residual rays, which includes the case where dissipation is taken
account of. This formula leads to two separate methods of esti-
mating the order of magnitude of the dissipation. Both these
methods show that the dissipation must be of the order of lo^- in cer-
tain units where Planck's theory leads to a dissipation of the order
10* in the same units. Thus the source of dissipation pointed out
by Planck is about lo- times too small to account for the smallest
case of dissipation known to us.

I am inclined to think that the most general type of absorption
of light by bodies of this class is of the following character. We
have seen that the electrons execute forced vibrations under the
influence of the incident light. When the period of the light ap-
proximates to the free period of the electron the electrons absorb a
great deal of energy from the light. In general this absorption of
energy will go on until the vibrations carry the electron out of its
region of stability. A rearrangement of the system will then take
place and during this rearrangement a great deal of the kinetic
energy which the electron has accumulated will be transferred to other
parts of the substance and will make itself felt as heat. As far as
that particular electron is concerned the sympathetic vibrations will
have to be established all over again. It is not necessary to suppose
that during this process the electron is actually carried out of the
atom when it breaks loose from the region of stability. The whole
occurrence may take place in the one atom. On the other hand we
know a great many cases of bodies which emit electrons under the
influence of light and in these cases the electrons must get carried
out of the atom. It seems to the writer to be an advantage
of this view that it connects the absorption of light with the so-
called photo-electric effect. As a first approximation this view of
the absorption of light leads to the same relation between absorption
and frequency as does the assumption of a retarding force propor-
tional to the velocitv.

360 RICHARDSON— DYNAMICAL EFFECTS OF [April 22,

There is another point in this connection that is not without in-
terest. On any theory of absorption the natural periods of a sub-
stance are characterised by conferring on it either intense absorp-
tion or intense opacity. It is therefore evident that they can be
detected very readily by experiment. From an analysis of the nat-
ural periods of a large number of substances which has been carried
out by Drude it appears that there are two types of vibrations which
occur. In the one the electron forms the vibrating system and in the
other one of the constituent atoms or a group of atoms vibrate as a
whole. Owing chiefly to the enormous difiference between the mass
of an electron and that of an atom there is an enormous difference
between the frequency of the two types. The electronic type
always gives rise to frequencies in the ultra-violet part of the spec-
trum and the atomic type to natural frequencies in the infra-red.
It is therefore not an accidental circumstance that almost all chem-
ically pure substances which are not conductors of electricity are
transparent in the visible spectrum.

The action of Roentgen rays on matter is a subject of great inter-
est. According to the ether pulse theory of these rays elaborated
by Sir J. J. Thomson, the relation between the Roentgen rays and
sodium light is similar to that between a series of sharp cracks and a
musical tone. And on the modern view of the nature of white light
the difference between white light and the Roentgen rays is one of
degree rather than kind. The cracks corresponding to Roentgen
rays are much sharper than those which correspond to white light.
According to the principles of harmonic analysis which we owe to
Fourier it should be possible to resolve either of these kinds of
radiation into simple harmonic elements. I have estimated that the
average frequency of these elements for the Roentgen rays would
be 10,000 times greater than that for those which form white light.
This estimate is based on the view that the kinetic energy of the
electrons emitted by bodies under the action of ultra-violet light and
Roentgen rays is a function of the frequency of the equivalent vibra-
tions. The experimental results indicate that the functionality is a
linear one and there is considerable theoretical support for this view
Some investigators have maintained that the square root of the
energy is proportional to the frequency; but even if this extreme

191 1.] AGGREGATES OF ELECTRONS. 361

view is taken the estimated frequency is not changed enough to
affect the general argument.

If the Roentgen rays are so much Hke white hght you will at
once ask why they are not deviated by a prism. The answer is very
simple. It follows from the principles of the electron theory that
the refractive index /a of a substance for electromagnetic vibrations

of frequency p is given by ^- ^ i -|- 2 — t — f 2\ "^vhere e is the

charge on an electron, in its mass, />., its natural frequency and vs
the number of electrons of type .s^ in unit volume of the material. In
general this formula will not be exact on account of the interactions
of the electrons on one another but it will give results of the right
order of magnitude. Xow c and ;;; have the same value for all
electrons and in the part of the spectrum near the visible vgC-frnpa^
is of the order unity for such frequencies /',, as fall within that
region. Xow r., will always be of the order of the number of mole-
cules per cubic centimeter whichever of the .y classes of electrons we
consider, so that we may draw the following conclusions : ( i ) On
account of the very great absolute value of p. ft- will be equal to
unity except for a very narrow range in the immediate neighbor-
hood of p = pg- (2) Only such substances will be capable of re-
fracting the Roentgen rays as have natural frequencies ps which lie
within the range of values of p embraced by the Roentgen rays ex-
perimented on. In any event it is clear that with a mixed group
of rays such as is emitted by an ordinary X-ray bulb, practically the
whole of them will pass through a prism without deviation.

Barkla's experiments on secondary rays show that the Roentgen
rays exhibit phenomena very much akin to fluorescence in optics.
One interpretation of Barkla's results would be that there are in
material atoms natural frequencies comparable with the frecjuencies
in the Roentgen rays. In that case, although almost the whole of a
beam of Roentgen rays would be undeviated by a prism there
should be a small amount which would be deviated. At present I
am making experiments to detect this effect.

Of course if one adopts the corpuscular view of the Roentgen
rays recently developed by Bragg, eft'ects of the kind described are

362 RICHARDSON— DYNAMICAL EFFECTS OF [April 22,

not to be expected. At present the balance of evidence seems to be
decidedly against the corpuscular view.

I am inclined to think that the primary Roentgen rays originate
largely as the result of secondary actions due to the stirring up
of the electrons in the atoms of the anti-cathode by the rapidly mov-
ing cathode rays which impinge on them. On this view the con-
stituent frequencies of the rays would be, to a considerable extent,
a matter of the atoms in which they originate ; and it may be that the
gap in electro-magnetic radiations between ultra-violet light and the
Roentgen rays, which exists at present, may never be filled up ; as
there may be no atoms which have natural periods in the neighbor-
hood of these frequencies.

Recent years have seen the accumulation of a very large quantity
of material relating to optical efl^ects which are produced by a mag-
netic field. It is impossible, within the limits of this discussion, to
attempt to show the enormous usefulness of the electron theory in
the development of the science of magneto-optics ; but there is one
phenomenon which we cannot afford to pass by entirely, if only on
account of its historical importance. I refer to the Zeeman effect.
This effect was called after its discoverer, who showed that the
spectral lines which are emitted by all gaseous substances under
suitable conditions of excitation, were slightly displaced by a very
strong magnetic field. The true explanation of this phenomenon
was at once given by H. A. Lorentz. He pointed out that if the
monochromatic light was emitted by vibrating electrons the fre-
quency of the vibrations would be altered if the atom which con-
tained the electrons found itself in a magnetic field. This change
in the frequency, of course, corresponds with a change in the wave-
lengths of the emitted light. He also predicted that the emitted
light would be polarized in a certain v/ay and this was confirmed by
experiment. Lorentz showed, in addition, that the value of the
electric charge of an electron, divided by its mass, could be calculated
from the displacement of the spectral lines in the magnetic field.
The results of these calculations showed that the value of this ratio
was the same as that found by Sir J. J. Thomson and Wiechert for
the cathode rays in a discharged tube. Thus the Zeeman effect and
the cathode rays were the first two phenomena which aff'orded ex-

191 1.] AGGREGATES OF ELECTRONS. 363

plicit evidence of the existence of these minute charged particles,
whose mass is nearly 2,000 times smaller than that of the lightest
known chemical atom.

The emission of ordinary heat radiation such as is given out
by all substances, and in increasing amount the higher the tempera-
ture, is very intimately connected with the theory of electrons. As
is well known this radiation is electromagnetic in character and in-
cludes visible light as a particular case. We also know that when
an electron is accelerated it emits electromagnetic radiation. It
is natural therefore to attribute the origin of this radiation to the
motions of the electrons of which material bodies are made up.
By making use of the principles of thermodynamics we can prove
that the nature of the radiation of this character which is to be
found in any enclosure maintained at a given temperature is inde-
pendent of the nature of the walls of the enclosure. The amount
and character of this radiation is thus independent of the material
from which it originates. If therefore we can calculate the amount
of this radiation of each wave-length for any particular substance,
for a series of temperatures, we shall know what it is for all sub-
stances at the same temperatures. Unfortunately when such a
calculation is carried out in the most logical and natural way it
leads to results which are not in agreement with those given by
experimental measurements. Another mode of calculation given by
Planck leads to a formula which agrees with the experimental values.
It has been shown however that Planck's calculation involves the
implicit assumption that energy is an atomic or discontinuous quan-
tity. This idea is distasteful to many physicists and it is so revolu-
tionary that it is not desirable to adopt it without very convincing
evidence. One of the authorities on this very intricate subject,
Jeans, maintains that the reason for the discrepancy between the
less revolutionary theory and experiment is due to the fact, as he
asserts, that the experiments do not measure the true equilibrium
radiation. However this may be, the difficulties which lie in the
explanation of the connection between radiation and temperature
do not belong to the electron theory proper but are outside of it.
No matter how it may be decided the outcome of this question is
not likely to shake the foundations of the electron theory of matter.

•;64 RICHARDSON— DYNAMICAL EFFECTS OF [April 22,

3. The Number of Electrons in an Atom.

The behavior of very rapidly moving electrons in their passage
through matter is a very interesting subject of investigation. Thanks
to the discovery of the radio-active substances we are able to experi-
ment, if we wish, with electrons whose speed is almost equal to that
of light (3 X io^° centimeters per second). These rapidly moving
electrons are able to shoot right through the atoms of bodies, but
when in their flight they pass very close to one of the constituent
electrons their paths are deviated. When a group of them passes
through a considerable thickness of matter these deviations tend to
accumulate ; so that a group of electrons, all of which were moving
parallel to one another to start with, becomes divergent. Sir J. J.
Thomson showed how the average deviation arising from a single
impact could be calculated and also how the average divergence of
the beam, which was caused by its passage through a given amount
of matter, would depend on the number of electrons present in the
matter traversed.

Experiments made by Barkla showed that when matter, which
was made up of elements of low atomic weight, was traversed by
Roentgen rays it was caused to emit so-called secondary Roentgen
rays, which were precisely similar in character to the primary
Roentgen rays which excited them. A careful study of these second-
ary rays showed that they were primary rays which had been scat-
tered. The phenomenon is in fact very analogous to that which
gives rise to the blue color of the sky, which was shown by Lord
Rayleigh to arise from light scattered by innumerable small particles
present in the atmosphere. The amount of such scattering depends
on the number of particles which are engaged in doing it. In the
case of the Roentgen rays these particles are the electrons present
in the matter, each one of which is set into violent motion by the
Roentgen ray pulse. The exact way in which the amount of the
scattering should depend on the number of electrons engaged in the
operation was figured out by Thomson who showed from Barkla's
experimental results that the number of electrons reckoned per atom
of the material was comparable with the atomic weight.

We have seen already that information of a like nature may be

191 1-] AGGREGATES OF ELECTRONS. 365

obtained from the spreading out of a beam of rapidly moving
electrons when they traverse a layer of matter. Working over such
material as was then available Thomson found his conclusion, that
the number per atom was comparable with the atomic weight, was
strengthened. Quite recently J. A. Crowther has made a very care-
ful experimental investigation covering both these lines of inquiry.
He finds that Thomson's calculations are borne out very satisfac-
torily by his experiments and that the number of electrons which
go to make up each atom is three times the atomic weight of the
element.

PRI^'CETON University,
April, 1911.

IV.

THE CONSTITUTION OF THE ATOM.

By HAROLD A. WILSON, F.R.S.
(Read April 22, 191 1.)

According to Sir J. J. Thomson's theory^ atoms may be regarded
as rigid spheres of positive electricity containing negative electrons
which can move about freely through the positive charge. The
total negative charge on the electrons in an atom is equal to the
positive charge on the sphere. This theory has many advantages
over the theory of Sir J. Larmor, who regards atoms as systems of
positive and negative electrons in rapid motion. In the first place
the sphere of positive electricity provides a rigid and stable founda-
tion which is lacking in the other theory and which seems very neces-
sary to explain the extraordinary stability of atoms. It is difficult to
see how Sir J. Larmor's atoms could possibly survive the shocks of
continual violent collisions with other atoms.

Sir J. J. Thomson's theory has also the great advantage that it
explains the fact that only negative electrons can be isolated and that
positive electricity is always associated with atoms or molecules of
matter.

It also explains the fact deduced from the Zeemann efifect that
spectral lines are emitted by vibrating negative electrons and not by
positive electrons. It is consistent with the fact that atoms can
lose a few negative electrons without their identity being destroyed
which does not seem possible on Sir J. Larmor's view. The kinetic
theory of gases agrees best with the facts when the atoms are re-
garded as rigid spheres which again is strongly in favour of Sir
J. J. Thomson's theory.

This theory therefore may be used as a working hypothesis wdiich
enables a mental picture of the atom to be formed. It leaves the
nature of electricity and of the iether an open question and is conse-

' " The Corpuscular Theory of Matter," IQ07.

366

19 = I-] WILSON— CONSTITUTION OF THE ATOM. 367

quently much less fundamental than, for example, Lord Kelvin's
vortex ring theory. The negative electrons and the positive sphere
may or may not turn out to be modes of motion of the aether; at
present we cannot say.

One of the first questions which naturally arises in connection
with this theory is. how many negative electrons are there in each
atom? This question has been answered approximately by examin-
ing the effect of matter on light and Rontgen rays. When electric
waves pass over electrons the electrons are acted on by the electric
forces in the waves and so emit radiation. This means that the
electrons scatter the incident radiation. The amount of radiation
scattered by one electron can be calculated on the electromagnetic
theory and hence from the amount observed to be scattered by a
known amount of matter the number of electrons in the matter can
be estimated, the number of atoms in a given amount of matter
can be exactly calculated because we know the charge carried by
one atom in electrolysis and the total charge carried by the matter.
Hence we can get an estimate of the number of electrons per atom.
The total energy scattered by a mass containing .V electrons is

o__ „i

— jM — E where c is the charge on one electron, ;/; its mass and E
3 ^« '
the incident energy. This formula is due to .Sir J. J. Thomson.

The most recent determination of the energ}- scattered when
Rontgen rays pass through matter is that by Crowther.- He finds
that the number of electrons per atom of aluminium is 85, which is
about three times the atomic weight. Previous experiments of a
similar character have given nearly the same result for other
elements. It seems very probable therefore that all atoms contain a
number of electrons proportional to their atomic weights and not
very much greater.

The mass of a negative electron is only one seventeen-hundredth
part of that of an atom of hydrogen, so that the negative electrons
only account for about one six-hundredth of the mass of any atom.
The rest of the mass therefore must be the mass of the positive
sphere. According to this theory therefore the mass of matter is not
electromagnetic in its origin, for the electromagnetic mass of the

- Proc. Roy. Soc, A, Vol. 85, p. 29. 191 1.

368 WILSON— CONSTITUTION OF THE ATOM. [April 22,

positive sphere is negligible. This theory therefore does not support
the view which is the basis of the *' principle of relativity," that all
phenomena are electromagnetic in character. The mass and rigidity
of the positive spheres are assumed to exist and cannot be explained
by electromagnetic forces. There is no reason why the motion of
these spheres through the ather should not produce effects capable
of being detected and which would enable us to determine the veloc-
ity of the earth relatively to the xther. The fact that this has not
yet been done does not prove that it is impossible.

According to Sir J. J. Thomson's theory the properties of dif-
ferent atoms are due to the number and arrangement of the electrons
in the positive sphere. The problem of the distribution of 11
electrons in a positive sphere has not been solved and is very
complicated, so Sir J. J. Thomson investigated the much simpler
problem of the distribution of /; electrons in a plane wdien they are
all acted on by forces of attraction proportional to their distances
from a fixed point in the plane.

This problem can also be solved experimentally by means of
Professor Mayer's floating magnets. The electrons arrange them-
selves in concentric rings. Thus six give a ring of five and one in
the middle. Seventeen give a ring eleven, a ring of five and one
in the middle. Thirty-two give rings of fifteen, eleven, five and one
in the middle. Forty-nine give rings of seventeen, fifteen, eleven,
five and one in the middle.

With two in the middle we get a series of rings containing 8,
12, 16, 19 and 22 electrons respectively and a similar series with
three in the middle and so on.

This leads to a very interesting suggestion with regard to the
series of elements which have similar properties for example:

Helium, neon, argon, krypton, xenon; hydrogen, lithium, sodium,
potassium, rubidium, caesium ; fluorine, chlorine, bromine, iodine.

Sir J. J. Thomson suggests that each element in such a series
may be derived from the one before it by the addition of another
ring of electrons the arrangement of the inner rings remaining un-
changed. This explains the similarity of the properties of the
elements in such series.

On this view an atom of bromine is an atom of chlorine with the

191 1.] WILSON— CONSTITUTION OF THE ATOM. 369

addition of one more ring of electrons together with the additional
amount of positive electricity required to keep the atom neutral.
Sir J. J. Thomson has shown that many of the facts connected with
Mendeleeff's periodic law can be explained on this theory.

In the atoms of course the electrons are not really confined to
one plane but are distributed throughout the volume of the positive
sphere, so that instead of concentric rings of electrons there are
concentric spherical layers. An atom of bromine is therefore de-
rived from an atom of chlorine by the addition of one more layer,
the inner layers remaining unchanged.

Although the exact solution of the problem of the distribution of
n electrons inside a positive sphere is too complicated to be worked
out I find that an approximate solution can be obtained without
much difficulty, which enables the results of the theory to be com-
pared with the atomic weights of the elements.

Consider an electron having a negative charge c inside a sphere
of positive electricity of uniform density of charge p per c.c. Close
to the electron the electric field is of strength e/r-, where r is the
distance from the electron, so that ^irc tubes of electric force come
out of the electron, if the number of tubes per sq. cm. is taken to
be equal to the field strength. Consider one of these tubes of force
and let ds be an element of its length and a its cross section at ds.
The charge in the length ds is pads, so that

Fa — lFa-\- -. iyFa)ds j = ^irp'X'/s,

where F is the electric force along ds. Hence

— d(Fa) = ^irpads ,
which gives

FjCZi — Fa^ 4Trpfa.ds.

where F^cti denotes the value of Fa. at the surface of the electron.
This shows that as we go along the tube Fa diminishes and when
Fj^ai^4-n-pfads it will be zero and the tube will end. Xow F^ =
c/o-, where a is the radius of the electron and a^^^a'/e, so that
Fiai = i, hence ^irpfads from the surface of the electron to the
end of the tube is equal to unity. Thus the positive charge in each

PROC. AMER. PHIL. SOC, L. 200 X, PRINTED AUG. 4, Igll.

370 WILSON— CONSTITUTION OF THE ATOM. [April 22.

tube is i/47r so that its volume is i/^irp. The total volume of all
the 47rr tubes is therefore e/p. Thus the tubes of force starting
from the electron occupy a volume c/p and this is true in any case
whether other electrons are near or not. Also since every tube of
force must end on positive electricity it is clear that the volume c/p
can only contain the one electron from which the tubes start. Thus
when any number of electrons are present each one will be sur-
rounded by its own field which will occupy the volume e/p. The
positive charge in the volume c/p is equal to c, so that if the sphere
has a positive charge equal to the total negative charge on the n elec-
trons in it, it will be divided up into ;; equal volumes, each contain-
ing one electron.

The energy in an element of a tube of force is equal to
F-ads/S-rr, and if the tube is slightly distorted this element will still
have the same volume and also (Fa) will remain unchanged so that
the change in the energy in the element will be due to the change in
F. The energy will be a minimum when the tube is in equilibrium
so that F will be as small as possible and therefore a as large as
possible. This means that the tubes tend to become as short as pos-
sible, their volumes remaining constant. The effect of this will
evidently be to make the field round each electron tend to become
as nearly spherical as possible with the electron in the middle.

Consequently to determine approximately the distribution of
the 11 electrons in the positive sphere it is sufficient to find how the
sphere can be divided up into .V equal volumes, all as nearly spher-
ical as possible and put an electron at the center of each of the n
volumes.

When Ji is large it is easy to see that this requires the electrons
to be arranged like the centers of the shot in a pile of shot. Thus
with thirteen electrons we should have one in the middle and twelve
arranged around it, all at the same distance from it.

Suppose the volume of the field of one electron is z', and let
«i, »2, "3, etc., denote the number of electrons in the atoms of a
series of similar elements. Each element is formed by the addition
of a spherical layer to the one before it and it is clear that all the
layers must be of nearly the same thickness if the fields of all the
electrons are to be nearly spherical. Consecjuently if i\,i\,r^, etc.,

191 1.] WILSON— CONSTITUTION OF THE ATOM. 371

denote the radii of the atoms in the series we should expect to have

To — i\ = Tg — r„ =:r r^ — Tj = etc.

Let A^, A.^, A^, etc., denote the atomic weights and suppose
/SA^^u^, ^A.^^n.-,, etc.. where ^ is a constant. Then we have

Hence

m

(r ,. — r ) = A ,,'- — A 3 = C,

\ m+l m/ m + 1 m '

3^r

where C is a constant which should be the same for all series of
similar elements.

Also ('',„+^ — r„i)^^t' approximately, so that

According to the theory therefore we ought to be able to find the
number of electrons per atom from the atomic weights.

In the figure the values of Ai for series of similar elements are
plotted against the order of the elements in the series. For some
series a constant has been added to the values of Ai to prevent the
different lines falling too close together. It will be seen that
the values of Ah for each series fall nearly on straight lines
and that the different lines are nearly parallel. This shows that
Am+^i — A,ni = C is nearly constant, as was to be expected from the
theory. The mean value of C is o.8i. Hence w'e get ^ = 8 so that
the number of electrons per atom conies out 8 times the atomic
weight in all cases.

This estimate agrees as well as could be expected with the num-
bers deduced from the optical properties of the elements which
might be expected to be too low.

We have assumed that the electrical density of the positive
spheres is uniform so that the approximate agreement of the atomic
weights with the theory confirms this assumption. It is easy to
see that the arrangement of the electrons in the positive sphere is
not afifected by a change in the size of the sphere provided its density
remains uniform and its total charge the same as before. It is

372

WILSON— CONSTITUTION OF THE ATOM. [April 22,

o _

Order in Series.

possible therefore that the adihlion of new layers increases the
density of tlie positive spheres inslead of increasing' tlieir size. If

191 1.] WILSON— COXSTITUTIOX OF THE ATOM. 373

this were ?o the calculation of /3 given above would not be affected
as can be easily seen.

The equation ( 477 '3/? )3 =.-J„j-i — A,„_^i gives

^„=(^>+(„,-,)(^;yy.

This equation enables the atomic weights of a series of similar
elements to be approximately calculated if that of the first in the
series is known. For example, if we take Aj^=i we obtain the
following numbers :

m Am

1 I H=i

2 6 L\ = y

3 18 Na = 23

4 40 K = 39

5 77 Rb = 85

6 129 Cs=i33

If we take A^ = c) we obtain the following numbers:
/;/ Am

1 9 Be = 9

2 24 Mg^24

3 51 Ca = 40

4 92 Sr = 87

5 150 Ba=i37

6 230 Ra = 226

It will be seen that the numbers given by the approximate
formula deduced from Sir J. J. Thomson's theory agree approxi-
mately with the atomic weights. I think this must be regarded as
strong evidence that there is a considerable element of truth in
the theory.

I believe that this is the first time that a definite theory of
atomic structure has been worked out sufficiently to enable a com-
parison between theoretical results and the known atomic weights
to be made.

McGiLL University,
Montreal.

THE HIGH VOLTAGE CORONA IN AIR.

; . By J. B. WHITEHEAD.

(Read April si, 1911.)

The term "corona" as employed by electrical engineers refers to
the luminous envelope which surrounds a bare electrical conductor
when its potential is raised above a certain value. As the voltage of
long-distance transmission lines has been raised to higher and higher
values in order to reduce the size and cost of the conductors and so
increase the distance of economical transmission, a limiting condition
has been found in the insulating properties of the atmosphere. For
each definite space separation and size of conductors, above a certain
value of voltage the regions immediately surrounding the conductors
become luminous, and a power loss sets in which increases rapidly
with further increase in voltage.

These facts were first noted by electrical engineers in this country
in 1896. It was promptly recognized that the region in the imme-
diate neighborhood of the conductors is subject to the greatest electric
intensity and that the phenomena are due to local though restricted
break-down of the air. This was corroborated not only by the pres-
ence of the luminous envelope immediately around the conductors,
for voltages above that at which the loss begins, but by study of the
eft'ect of changing the size and separation of conductors ; decreasing
separation and size both increase the surface electric intensity and
therefore lower the voltage at which loss begins. The electric inten-
sity at the surface of the conductor may be readily calculated in most
cases that occur from the voltage and from the separation and sizes
of the conductors. It is directly proportional to the voltage in all
cases. The term "corona" was first used by Steinmetz in 1898 to
describe the luminous enveloi)e and has been generally adopted by
engineers.

^fany measurements have been made on electric power transmis-

374

191 1.] WHITEHEAD— HIGH VOLTAGE COROXA IN AIR. 375

sion lines in efforts to determine the law connecting the voltage at
which loss begins with the physical constants of the line. These
measurements have shown marked Inconsistencies among themselves,
the results on the same lines on different days being often at variance.
A number of laboratory investigations, in which the widely varying
conditions of a transmission line are under control, have naturally
followed. They have indicated with a rather wide variation in nu-
merical values that the critical voltage or voltage at which corona
begins on round wires varies inversely as the temperature and directly
as the pressure : also that the electric intensity under which the air
near the surface of the conductor breaks down has not a constant
value but increases markedly for conductors of small diameter ; and
further that the value of the intensity at which break-down begins is
that corresponding to the maximum value of the alternating wave,
and is independent of the material of the conductor.

The general nature of the influence of temperature and pressure
could probably have been predicted from numerous investigations of
the discharge of electricity through gases ; the cjuantitative relations
for pressures near that of the atmosphere do not, however, appear
to have attracted the physicist, nor indeed have they as yet been
satisfactorily determined for the voltage of corona formation by-
experimental engineers. The accumulated results of physical inves-
tigation and theory, however, oft'er no obvious explanation of the
rise of the critical surface intensity for smaller wires, nor of the
influences of the form and frequency of alternating voltage. The
fact that the corona voltage is that corresponding to the maximum
value of the alternating wave has been proven by stroboscopic
methods and by the use of distorted wave shapes. It indicates that
the time element involved in the process of break-down of the air
is short compared with the periods of the common alternating cur-
rent circuits. The apparent sharpness of the connection removes
many objections to the use of the alternating electromotive force as
a means of investigation, and renders available its many advantages.
It is only necessary to know the shape of the alternating wave and
this may be obtained readily by several well known methods. Effec-
tive values as read on direct reading instruments may thus be used

376 WHITEHEAD— HIGH VOLTAGE CORONA IN AIR. [April 21,

and the corrective factor for the maximum vahie is obtained from
the shape of the wave.

Many of the inconsistencies among the measurements on existing
transmission hues and those made in laboratories arise in the difficul-
ties of measuring the power in high voltage circuits ; the instruments
must be placed in the low voltage side of transforming apparatus, the
losses in which, being generally greater than those to be measured,
introduct a troublesome source of error. The appearance of the
visible corona has been used by laboratory workers as an indication
of the beginning of loss through the air. With proper precautions
this method may be very reliable but its use is generally attended by
danger of subjective and other error. As a result of the discrepan-
cies among these approximate determinations of various investiga-
tors, there has appeared much speculative suggestion of the presence
of other unrecognized influences, as for example the moisture con-
tent of the air, the presence of " free " or natural ionization, an ab-
normal property of air when near a small wire, etc.

The present problem therefore resolves itself into two parts:
first, a satisfactory method for the determination of the law under
which the air in the neighborhood of a long straight and usually
cylindrical conductor breaks down under electric strain ; and second,
the law governing the amount of loss when the voltage is carried
above the critical value. A year ago the writer^ described a method
by which it is possible to determine the voltage at which the air
breaks down near a round wire to a maximum inaccuracy of a few
tenths of one per cent. The original paper may be consulted for
the details, but the principle is simple and may be described briefly.
The wire is stretched along the axis of a metal cylinder and the
voltage is applied between them. Air may be passed through the
cylinder by means of two lateral tubes near the ends, the walls of
the cylinder at these points being drilled with a number of small
holes. Close to one set of these holes and outside the cylinder a wire
mesh electrode connected to a sensitive electroscope is placed. As
soon as the air around the wire breaks down under increasing volt-
age, copious ionization sets in which causes a rapid leak from the

'J. B. Whitcliead, Proc. A.I.E.E., p. 1059, July, 1910.

I9II.]

WHITEHEAD— HIGH VOLTAGE CORONA IN AIR.

377

charged electroscope. The initial discharge of the electroscope is
very sharply marked. Observations may be repeated at will and
after any interval ; when corrected for temperature and pressure a
most satisfactory constancy of results is obtained. Fig. i indicates
the essential parts of the apparatus. In the following a short de-
scription is given of the results of investigations of the influence of
the diameter of the conductor, of stranding the conductor, of the
alternating frequency, of wave form, of pressure, of moisture con-

FiG. I. Arrangement of apparatus.

tent and of temperature on the electric intensity at which atmos-
pheric air breaks down. The experiments on temperature, moisture
content and diameter of conductor are given in the paper mentioned
above. The results of the remaining investigations are first given
here. Xo attempt is made to describe the details of the experiments.
For these the reader may refer to the earlier paper and also to one
shortly to be presented to the American Institute of Electrical Engi-
neers in which the practical bearing of the results will be discussed.
Influence of Diameter of Conductor. — For convenience of refer-
ence a condensed table of the results on this portion of the work

378

WHITEHEAD— HIGH VOLTAGE CORONA IX AIR. [April 21.

is given in Table I. and the results are plotted graphically in Fig. 2.
For comparison, points observed by other investigators are also
shown. The values are all corrected for temperature, pressure and
wave form and give the maximum values of the electric intensity
at which the air breaks down under a pressure of 760 mm. of

TABLE I.
Rel.\tion Between Di.a.meter .\nd Critical Surface Intensity.

Diameter,
cm.

Material of
Wire.

Diameter of
Tube, cm.

Material of
Tube.

Critical Primary
Volts Corrected.

Ratio.

Maximum Crit-
ical Surface

Intensity.

0.089

Copper

4.9

Brass

74-5

125.09

77,100

0.122

u

<<

44.0
87.8

250.18
125.09

70,950
70,800

0.156

>,

<<

97.0
97.0

65,880
55,880

0.205

((

6

35

'<

(8)

109.5
55-0
60.5
60.2
59-9

250.18

61.350
61,500
62,080
61,780
61,680

0.254

Aluminum

"

65-9

58,750

0.276
(1

Copper

"

(8)

68.9
68.8
68.5
69.0
68.9

58,080
58,080

"

"

9-52

Steel

77-3

57,650

0-325

Aluminum

6.35

Brass

72.8

55,000

0.347

Copper

6.35

"

75-13

54,500

0 3405

9.52

Steel

85-7

55.100

0.399

Steel

"

"

92.5

53,050

0.475

"

"

"

100.6

51.400

mercury, and at temperature 21° C. I am indebted to Professor
Alexander Russell for pointing out that these results obey a very
simple law. If E be the critical electric intensity in kilovolts per
centimeter and d the diameter of the conductor in centimeters, the
curve of Fig. 2 obeys closely the ecjuation :

£ = 32 + 13-4 i/V^- (i)

The observed values of Table I. are compared with the values cal-
culated from the above formula in Table II. The percentage error
is also given, and it is seen that with one exception the difference
is well within one per cent. The exception refers to an aluminum
wire which could not be polished to a clean surface ; a rough sur-

ipll.]

WHITEHEAD— HIGH \'OLTAGE CORONA IX AIR.

379

TABLE II.

Kilovolts per Centimeter.

Dift'erence, Per Cent.

Calculated.

Observed.

.089

76,950

77,100

— 0.19

.122

70,400

70,875

+ -67

.156

65,950

65,880

— .1

.205

61,600

61,680

+ .13

.254

58,600

58,750

+ -25

.276

57,500

58,000

+ .87

.325

55,600

55,000

— 1.08

.340

54,980

55,100

4- .21

.347

54,780

54,500

— •SI

•399

53,230

53-050

— -23

•475

51,460

51,400

— .11

face invariably lowers the critical intensity. The corresponding
point falls below the curve of Fig. 2.

The closeness with which this simple law is followed by the
measurements suggest a considerable value of the method for a

80

o

uj 5C

o ;o

\

1 ! ! ! ! 1

t

%^

A

j^^^k.^

A

^

■^...^

;^

<L

-^

S

A.C.

^^^

--^

D

o.c|

32+^

i

* W

1

0 - RYAN

_€^MERS
-- WATS

1

HON ;
ON

—

!

1

1

! j

12 3 4 5 6

DIAMETER MILLIMETERS

Fig. 2. Relation of critical intensity and diameter.

380 WHITEHEAD— HIGH VOLTAGE CORONA IN AIR. [April 21,

physical investigation of the nature of the process involved in the
electrical break down of the air. The formula indicates that the
value of electric intensity of a uniform field or near the surface
of a plane conductor, at which air would break down is 32 kilovolts
per centimeter. The work of von Scweidler, Townsend and others
indicates that at about 30 kilovolts per centimeter, secondary ioniza-
tion or ionization by collision sets in between parallel plates sub-
jected to a difference of potential. In a later paragraph several
other experiments are described which indicate that the start of the
corona in air is due to secondary ionization. So far as the writer
is aware however no theory has been advanced to explain the
influence of the curvature of the conductor. That the nature of the
molecular structure of the air is concerned there can be no doubt,
but the variation of values of critical intensity occurs within a range
of diameter many orders of magnitude greater than molecular
dimensions, and is related to the diameter in a way which offers no
suggestion of explanation.

Effect of Stranding the Conductor. — It is quite obvious that if
the surface intensity is the determining factor in the voltage at
which corona occurs, then a stranded conductor should have a
critical voltage lower than that of a solid conductor of a diameter
equal to that of a circle tangent to the strands. On the other hand
it is not obvious that the critical voltage of a stranded conductor
would be less than that of a solid conductor of equivalent cross
section, for the diameter of the latter will always be less than
that of the enclosing circle of the former. Evidently also the rela-
tions will vary with the number of strands. The question is of
importance since all of the larger transmission lines consist of
cables or stranded conductors.

A series of observations was made on a number of cables of
stranding ranging from three to nine conductors uniformly filling
the outer layer. The interior space was filled with a single wire or
several wires of suitable size, but in each conductor the wires of the
outer layer were all of the same size, .162 cm. diameter. The cables
were clean and smooth and drawn tight along the central axis of the
outer cylinder of the apparatus. The results are condensed in Table
III, in which comparison is made between the diameter of a solid

igii.]

WHITEHEAD— HIGH VOLTAGE CORONA IX AIR.

381

TABLE III.

Strands.

(«)

(^)

(c)

{ic)

(c-/a)

Spiral Pitch,
Diams.

3

•349

.272

.247

1. 10

.708

10.9

4

.404

.332

.32

1.04

.792

8.65

5

■45

.381

.37

1.03

.822

9.S9

6

.49

.430

.42

1.026

■857

12.3

7

•541

.48

.465

1.032

.868

12.3

8

.5«9

.53

.516

1.027

.877

10.78

9

.64

.581

.567

1.025

.886

10.9

3

.336

.27

.207

1-305

.616

none

4

.378

.312

.25

1.248

.665

none

circular conductor having the same critical voltage as that observed
for the cable (column c) and the diameters of the circle just enclos-
ing the cable (a) and that given its equivalent section (b). The
ratios b/c and c/a are given in the last two columns, and are plotted
in their relation to the number of strands in Figs. 3 and 4 respec-
tively. Fig. 3 indicates that if instead of a solid conductor a
stranded conductor of equivalent cross section be used the critical

1 1

1.1,1 11

>>|0 ••'

V

1

0

\

s

c

^

^^

q:

—

— J

1

(_

.

1.0

n

1 1

_

1

3 6 7

NwMBer? Of Str^hoS.

Fig. 3.

voltage will be lowered, but by less than three per cent, if the num-
ber of strands is greater than 5. For a three-strand cable the lower-
ing is ten per cent.

The ratio c/a is more important however. This ratio compares
the diameter of a solid conductor having the same critical voltage
as the cable, with the actual overall diameter of the cable. It there-
fore refers the behavior of a given cable, with regards critical
voltage, to a solid round wire whose diameter is expressed as a
fraction of the overall diameter of the cable. This is a more logical

382 WHITEHEAD— HIGH VOLTAGE CORONA IN AIR. [April 21,

basis of comparison than the other since the interior of a multi-
strand cable may be made up in such manner as to cause, a con-
siderable variation in its cross section. In fact many transmission
cables have centers of hemp, or other material, the entire conducting
section residing in the single outer layer of strands. Thus Fig. 4
shows that a three-strand cable has a critical voltage which is that
of a single wire of seven tenths the overall diameter of the cable.
At nine strands the equivalent single diameter is still less than .9
that of the cable.

In a stranded conductor the strands are always spiralled. The
pitch of the spiral for the cables described above is given in Table
III. The spiral arrangement of the strands tends to lessen the
value of the electric intensity on the outer surfaces of the strands
since the equipotential surfaces are rendered more nearly cylindrical
about the axis of the cable. The values of maximum surface electric
intensity for cables of various numbers of strands and in which
there is no spiral may be computed from an expression given by
Jona- and due to Levi-Civita. This expression involves a hyper-
geometrical series whose evaluation requires some labor. As it
makes no allowance for the spiralling of the strands no deduction
may be drawn from the present observations as to the actual inten-
sity at which corona occurs on the stranded conductor. Values
deduced from the expression should, however, be of great value in
the study of the nature of the breakdown of the air when taken in
conjunction with measurements on cables without spirals. For in
these cases the maximum electric intensity at the outer edge of a
strand would obtain over a narrow circumferential distance, while
the same intensity reached at the surface of a single wire obtains
over a wdiole circumference. A comparison of corona voltages in
the two cases should throw light on the distances involved in the
process of secondary ionization and kindred phenomena.

At the bottom of Table III. there are given the results of obser-
vations on a three- and a four-strand conductor in which there was
no spiral. The size of the strands was the same as that of the
foregoing cables. The strands were carefully straightened, polished,

'Jona, Trans. Int. Elect. Congress, St. Louis. 1904, Vol. II., p. 550.

igii.]

WHITEHEAD— HIGH VOLTAGE CORONA IN AIR.

383

and built up by soldering with a line blow flame so that the strands
were uniformly tangent to each other throughout. The results indi-
cate the further lowering of the critical voltage when spiralling is
absent. The ratio c/a falls from .71 for the spiralled three-strand
to .61, and the difference for the four-strand is somewhat greater.
The pitch of the spirals of the cables investigated does not appear
to follow any regular rule. This irregularity however does not
appear to have any corresponding effect on the points of the curve

o

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^~

■^

.9

^

^

P"

r"

— J

^

--^

.8S

^

/I

/

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/

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Number or Strands.
Fig. 4.

of Fig. 4. From this it may be concluded that for a pitch of spiral
less than twelve diameters there is no gain on the ground of lessened
surface intensity due to the more uniform distribution of the elec-
tric field.

At this writing the author has been unable to obtain solutions of
Levi-Civita's expression as applied to three and four strands. These
would permit by the foregoing results a knowledge as to how the
maximum corona intensity for a round wire compares with that

364 WHITEHEAD— HIGH VOLTAGE CORONA IX AIR. [April 21,

at the surface of the same wire when made up into a three- or
four-strand cable without spiral.

Influence of Frequency and JJ'az'C Form. — By the use of a
cathode ray oscillograph in the high voltage circuit Ryan in 1904
showed that the appearance of corona was accompanied by a hump
or peak on the charging current wave in the neighborhood of the
maximum of voltage. The writer by stroboscopic methods has
shown that the corona is periodic, appearing every half cycle and
that its first appearance with rising voltage coincides accurately with
the maximum of the voltage wave. Also the duration of the corona,
with steady circuit conditions, may be reduced with lessening voltage
to a very small fraction of the period of the alternating electromotive
force. Thus a corona which was found to exist for only one
twentieth of a period at the crest of the voltage wave of a 60-cycle
circuit was plainly visible in a darkened room. It is evident, there-
fore, that the interval of time involved in corona formation and
cessation is extremely short. For these reasons it has been supposed
that the appearance of corona depends only on the maximum value
of voltage occurring in the cycle, and is therefore independent of
the frequency. Experience with existing lines indicates that if there
is an influence of frequency it is small for the range between 25
and 60 cycles. The closeness with which the critical voltage may
be read by the method described gave promise of discovering any
comparatively small differences due to variation of frequency. Sev-
eral series of tests were therefore made with different sizes of wire.
The observations are not recorded here as the points on the curve
of Fig. 5 are a sufficient indication of their accuracy. The range
from 15 to 90 cycles was obtained from two generators, and the
voltage from a lO-KW. 25-cycle 100,000-volt transformer. The
transformer had also a low voltage secondary coil. On the curves
the values of voltage are those measured at the terminals of this
coil ; these values are therefore proportional to the voltage in the
high tension winding and therefore to the electric intensity at the
surface of the wire. These observations were made with rods .716
cm. and .635 cm. in diameter placed at the center of a pipe 120 cm.
long and 30 cm. in diameter. The observations were taken as a

igii.]

WHITEHEAD— HIGH VOLTAGE CORONA IN AIR.

385

continuous set, interruption being necessary for only a few seconds
to change generators. There were consequently no appreciable
variations in temperature or pressure.

The results as taken are plotted in the lower curves of Fig. 5
in which observations for ascending and descending values of fre-
quency are plotted as crosses and circles respectively. The irregular
shape of these curves repeated itself accurately in experiments over

0

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UPPER

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Fig. 5.

the same range of frequency with other wires. Since the trans-
former was operating over a wide range of frequency at approxi-
mately the same value of voltage, and its magnetizing current was
therefore variable, a variation of wave form due to the armature
reaction of the generator appeared probable. Oscillograms were
therefore taken of the voltage at the terminals of the low voltage
secondary coil at frequencies 20. 35, 55, 60, 65 and 91 cycles, and
at transformer excitation corresponding to 50 volts on the same coil.
The ratios of maximum to effective values of these waves were

PROG. AMER. PHIL. SOC, L. 200 Y, PRINTED AUG. 5, I9II.

386 WHITEHEAD— HIGH VOLTAGE CORONA IN AIR. [April 21,

then determined by micrometer measurements of ordinates taken
every 7.5 degrees over two half waves. The several values of this
ratio so obtained revealed a minimum at 55 cycles thus explaining
the rise in the lower curves of Fig. 5 at that frequency. In the
upper curves the points indicated are the voltage of the lower curve
multiplied by the ratio of maximum to effective value as calculated
from measurements of the oscillograms for the corresponding
frequencies.

The upper corrected curves of Fig. 5 show a lowering of the
critical voltage with increasing frequency. The result leaves some-
thing to be desired in the accuracy of location of the points upon the
curve. It should be noted however that owing to the magnifi-
cation of the scale, the error of the points off the upper curves and
the 25-cycle portion of the lower curves is only about i per cent.
Several other sets of observations for different sizes of wire reveal
curves of the same general characteristics. The measurement of the
ratio of maximum to effective value from an oscillogram is subject
to considerable error. The maximum at 55 cycles, however, on
the lower curves is brought below the values for lower frequencies
when the correcting factor is introduced, and particularly, the lower-
ing at 91 cycles is far too great to be questioned on the score of a
possible error of this nature. The curves therefore show with a
fair accuracy the nature of the variation of the critical voltage with
the frequency. This variation within the range of the present com-
mercial frequencies 25 to 60 cycles per second, is only about 2
per cent.

Influncc of Pressure. — The influence of pressure on the various
forms of spark discharge has been closely studied. Paschen's^ law
states that the sparking potential for a given spark length is directly
proportional to the pressure ; his investigations covered the range
of pressure between 10 and 75 cm. of mercury. Carr* has shown
that this linear relation extends down to pressures of a few milli-
meters if the spark lengths are not greater than i cm. but does not
obtain for lower pressures. Townsend^ has shown that the potential

'Paschen, Wied. Ann., XXXVII., 79, 1889.
* Carr, Proc. Roy. Soc, LXXI., 374, 1903.
°Townsend, Phil. Mag., VI., i, 198, 1901.

I9II.] WHITEHEAD— HIGH VOLTAGE COROXA IN AIR. 387

gradient at which secondary ionization sets in when electricity is.
passing through a gas is directly proportional to the pressure. Wat-
son^ investigated the spark length between spheres up to fifteen
atmospheres and found that the spark potential increases with the
pressure in an approximately linear relation. From the general
similarity between the corona and the brush form of spark dis-
charge, therefore, a linear relation between pressure and critical
surface intensity, or the potential gradient at which corona begins
is to be expected. Apparently the only study of the influence of
pressure on the formation of the alternating corona is a single set
of observations by Ryan' on a wire .t,2 cm. in diameter placed at the
center of a cylinder 22.2 cm. in diameter. He observed the alter-
nating voltage at which the visible corona appeared for the range
of pressure between 45 and 90 cm. of mercury; the alternating
frequency was 130. The resulting linear relation is given as between
the kilovolts K actually applied and the pressure in inches of mer-
cury, i^ = 2.93 + -902 b.

In Table IV. are given the results of a typical series of observa-
tions on the influence of pressure on corona voltage; the values are
those for a wire .152 cm. in diameter. The wires were clean and
straight and centered accurately on the axis of the outer cylinder
of the apparatus which has been briefly described. This cylinder
has a diameter of 9.52 cm. The ends were closed with ebonite
caps of the same diameter and 5 cm. deep. The side tubes were
also closed by caps, and the leading-in wire to the discharge electrode
passed through a column of sulphur supported in hard rubber; no
troubles with either insulation or air leak were encountered with this
arrangement. All joints were sealed with a mixture of bees wax
and resin and pressures between 30 and 100 cm. of mercury were
reached without trouble. The discharge electrode was placed inside
the upper side tube and within one or two millimeters of the grating
formed by the holes drilled in the outer cylinder ; in the earlier work
it was found that a flow of air from the cylinder over the electrode
contributed little to the sharpness with which the condition of

* Watson, Electrician, 62, 851, 1909.
'Ryan, Proc. A.I.E.E., XXIIL, loi, 1904.

388

WHITEHEAD— HIGH VOLTAGE CORONA IN AIR. [April 21,

breakdown was indicated, the initial discharge of the electroscope
occurring at the same value for both moving and stationary air.
The results of Table lY. are plotted in the lower line of Fig. 6

TABLE IV.

Manometer.

Crit. Prin

Volts. Rati

Pressure,

), I : 125.

Right.
487.5

Left.

Diff.

mm.

102.2

102.2

102.2

587-5

— 100

659-5

97-5

97-5

97.2

459-5

605.5

T46

613-5

91-3

91-3

91.2

427

628.5

201.5

558

87.2

87-5

87.8

407.5

642

2345

525

83

83.2

834

386.5

656

269.5

490

79-9

80

80

367.5

6695

302

457-5

80.5

80.7

80.6

371

666.5

295-S

464

74

74

74

340

688.5

348-5

411

68.1

68.1

68.1

313-5

707

393-5

366

94.2

94.2

94.2

439

617

178

581.5

106.5

106

106.2

499

576.5

77-5

682

II4-5

114.9

114.8

545-5

545-5

0

759-5

Ratio 1 : 2^0

57-5

57-4

57-5

545-5

545-5

0

759-5

59-8

59-9

59-8

570.5

530-5

+ 40

799-5

61.8

61.6

61.7

592

516.5

75-5

835

64

64

63.8

618.5

499-5

119

878.5

66

641

486

155

914-5

67.7

67.7

67-7

661

473-5

197-5

957

69.8

70

69.9

687.5

457

230.5

989.5

71.6

71.6

71.7

710

444

266

1025.5

between the values of voltage at the primary terminals of the trans-
former and the pressure in millimeters of mercury. This voltage
is directly proportional to the corresponding value of potential
gradient at the surface of the wire. The ratios of transformation
were i to 125 and i to 250, the frequency 60, and the ratio of the
maximum to the effective value of the alternating wave of electro-
motive force, as measured from an oscillogram as already described,
was 1.46. The temperature was 24° C. The results for a .276-cm.
wire are also plotted in Fig. 6. The equations of the lines as drawn
in Fig. 6 have no significance since they apply to a particular com-
bination of wire and outer cylinder. The values of surface potential
gradient have therefore been calculated from the expression :

dV E

~di~~ R'

(2)

igii.]

WHITEHEAD— HIGH VOLTAGE CORONA IN AIR.

389

in which E is the maximum value of the potential difference between
wire of radius r and outer cyhnder of radius R, and which in this
case is the effective voltage multipHed by 1.46. Expressed in terms
of electric intensity at which corona begins, in kilovolts per centi-

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Fig. 6.

meter, and pressure in centimeters of mercury, the equation for the
.152 cm. wire is :

d{KV)

dr

and for the .276 wire

d(KV)
dr

15-2 + •673/'.

= 11. 6 + .595/',

(3)
(4)

390 WHITEHEAD— HIGH VOLTAGE CORONA IN AIR. [April 21,

While both equations are linear it is seen that the slope of that
for the smaller wire is the steeper, that is that the variation of the
critical surface intensity with the pressure is greater the smaller the
wire. It is interesting to note that the values at 76 cm. pressure
66.2 and 57 correspond extremely closely with the values 66.4 and
57.7 observed a year before and so calculated from the equation
of Fig. 2.

If Ryan's results for a .317-cm. wire be expressed in the same
terms used in the above formulae, the resulting equation of the
line is:

dr =6.15 + . 744 />. (5)

The slope of this line is greater than that of either the .152-cm. or
the .276-cm. wire as expressed in equations (3) and (4), although
the larger size of wire should cause the slope to be less ; also the
initial constant term is considerably less ; further the value of
critical surface intensity at 76 cm. pressure indicated by formula
(5) is 62.6, while that calculated from formula (i) and therefore
frequently observed by the writer is 55.7. Ryan used invariably
the visible corona for indication of initial breakdown ; some of his
results on wires of different size are plotted as circles in Fig. 2
where they are seen to be very irregularly located. Aside from the
uncertainty of the method of observation, the wave form and fre-
quency may have introduced considerable error in the results as
reported, although that due to frequency would have tended to a
lower rather than a higher value than for 60 cycles.

Further experiments on the variation of the pressure equation
with the size of wire are in progress.

Inflncnce of Temperature and Moisture. — No satisfactory inves-
tigation has been made of the influence of temperature on corona
voltage. Ryan reports a series of observations on the visible corona
for temperatures between 70° and 200° Fahrenheit. The size of
wire is not stated. The results are admittedly wanting in accuracy,
but indicate a linear relation between corona voltage and tempera-
ture ; in fact, Ryan states that the maximum value of corona voltage
varies inversely as the absolute temperature.

191 1.] WHITEHEAD— HIGH VOLTAGE CORONA IN AIR. 391

The writer has conducted a short series of tests between 6° and
41° C. on a .27-cm. wire for the purpose of obtaining a correction
factor for his various observations as taken at different tempera-
tures. The result as stated in the paper already referred to is that
the relation is linear and that for each degree rise or fall from 21°
C. there is a lowering or raising in the value of the critical voltage
of 0.22 per cent. ; Ryan's results indicate 0.27 per cent, for this
value. Expressed in terms of surface intensity in kilovolts per centi-
meter and temperature in degrees Centigrade the writer's results
may be expressed by the formula :

KV./Cni. = 6i — .iT,2t. (6)

In view of the observations of the effect of variation of pressure on
different sizes of wire, it is not improbable that the constants of
equation (6) will also vary with the size of wire. Further investi-
gation in this direction is therefore desirable.

Moisture content up to amounts quite close to saturation have
no effect on the values of voltage at which corona begins. While
there is still some dissent from this opinion among electrical engi-
neers, the author's results on this question, described in the earlier
paper, appear very conclusive, and have been widely accepted. An
influence of moisture on the amount of power loss above the critical
voltage appears quite probable, in the light of the ionization theory
in which the mass of the ionic carriers, which make up the current
are an important factor in its value.

Discussion.

So far as the question of the value of voltage at which corona
will start on a given transmission line is concerned, it is probable
that a solution will be reached sooner or later by means of experi-
ments of the general character as those described above, supple-
mented by observations on existing lines. Also, there is good reason
to suppose that a comparatively simple law will be found. For the
surface intensity for any arrangement and size of cylindrical con-
ductors, corresponding to a given voltage, may be expressed in terms
of these constants ; and the critical or corona intensity, under stand-

392 WHITEHEAD— HIGH VOLTAGE CORONA IN AIR. [April 21,

arc! conditions of temperature and pressure, is a simple function of
the diameter of the conductor. The relation between pressure
within the range of the atmosphere, and critical voltage, for a given
size wire, is linear ; and although the slope of the linear relation
changes with the size of wire there is good reason to suppose that
a simple law connecting them can be found. Aluch the same may be
said of the influence of temperature; preliminary experiments show-
ing that the linear relation exists over a fairly wide range. The
effect of stranding the conductor has been studied for only one size
of strand as yet, but it seems a simple matter, with some further
investigation, to express the effect of each of these influences in
terms of the diameter of the conductor.

The influence of the frequency does not offer promise of expres-
sion as a simple relation ; this influence is small however within the
limits of frequency met in practice. The state of the atmosphere
appears to be of small importance, for moisture does not influence
the critical voltage, nor does its state as regards ionization, as is
indicated by several considerations given in a later paragraph. Dirt
and impurities which on settling cause irregularities on the surface
of the wire, may lead to localized brush discharges; and if these
are sufficient in number they may cause a noticeable loss below the
normal critical voltage.

It is of great interest, however, to consider the results in their
relation to present theories of the nature of the electric conductivity
and breakdown of a gas. It is assumed that the reader is familiar
with the general features of the theory of ionization. Under this
theory the neutral atoms and molecules of matter may be separated
into smaller charged particles, and the motion of these particles under
electric force constitutes an electric current. In a gas there are
always a small number of these free ions present ; this number may
be greatly augmented by Rontgen rays, ultra-violet light and other
well known ionizing agents. When so ionized currents of magni-
tudes within easy measuring range are obtained between terminals
subject to a difference of potential. If this difference of potential is
increased, a point is reached where the current increases sharply,
showing the presence of some new saurce of ionization. The theory

191 1-] WHITEHEAD— HIGH VOLTAGE CORONA IN AIR. 393

states that these new ions are formed by the impact of those already-
existing, and moving with higher velocity in the increased electric
field, with the neutral molecules of the gas. This phenomenon has
been called ionization by collision or secondary ionization.

The results of the experiments which have been described above
are for the most part consistent with the ionization theory. The
various circumstances surrounding the appearance of corona all indi-
cate that it is an instance of secondary ionization. Formula (i)
indicates that near a conductor of large radius or near a plane, the
corona intensity approaches a value t,2 kilovolts per centimeter ;
secondary ionization between plane electrodes in closed vessels at
atmospheric pressure has been noticed by several physicists to begin
in the neighborhood of 30,ocx) volts per centimeter. The mass of
elementary negative ion or electron is approximately 5.9 X lO"-* gms.
and the charge it carries is 4.6 X lO'^" electrostatic units. In an
electric field the mechanical force acting on the electron is the
product of its charge and the strength of field. Hence by the laws
of simple mechanics it is possible to calculate the acceleration, the
velocity and the kinetic energy attained by an electron in moving a
given distance under a given electric intensity. If the mean free
path of the electron, about 6 X lO"' cm. at atmospheric pressure, be
the distance between collisions, it is thus easy to calculate the kinetic
energy of the electron due to the electric field, when it collides with
a molecule. This energy is readily seen to be equal to pVc, where p
is the mean free path, V the electric intensity in electrostatic units,
and e the charge of the electron. If now the voltage between plane
parallel electrodes be raised until secondary ionization begins, the
value of the voltage makes it possible to calculate the energy re-
quired to ionize a molecule of a gas. In fact the values of the
energy required to ionize a molecule which are now generally ac-
cepted are largely based on determinations of the value of electric
intensity at which secondary ionization begins. It has been pointed
out above that the values of this intensity as determined by Town-
send and others are in close agreement with the value 32,000 volts
per centimeter indicated by equation ( i ) as the lowest value at which
corona appears. To one skeptical as to the correctness of the theory
of ionization therefore (and there are many such) all that may be

394 WHITEHEAD— HIGH VOLTAGE CORONA IN AIR. [April 21,

said so far is that the phenomena of sudden increase of current above
a certain value of electric intensity as observed by Townsend, and
that of corona formation, are probably due to the same causes. But
there are several other independent methods of determining the
energy required to ionize a gas. The values are commonly ex-
pressed in terms of the potential difference in volts through which
the electron must pass in order to acquire energy sufficient to pro-
duce an ion by collision. The value pertaining to the method de-
scribed above is from 10 to 12 volts. Rutherford, from the relation
between the heating eft'ect of radium and the number of ions it pro-
duces, gives the value 24 volts. Stark and Langevin by independent
methods conclude that the values are 45 and 60 volts respectively.
While the extreme values dift"er by the factor 5 or 6 it must be re-
membered that the actual amount of energy required to produce an
ion is about 5 X lO"^^ ergs, so that all of these values indicate the
same order of magnitude ; therefore when taken together they con-
stitute a very strong reason for supposing the value 5 X lO"^^ ergs
is close to the correct one. If this be true it is good evidence that the
formation of the corona is actually due to the liberation of ions from
the neutral molecules of the gas, when the latter suffer collision from
a free electron moving under the force of the electric field. That
the electron and not a gaseous ion or aggregate is the active agent
is shown by the shorter free paths of these latter which by the
relation already given results in a lower value of kinetic energy at
the time of collision than those given above.

The writer has shown by stroboscopic methods that above the
critical voltage the corona begins and ends at a point on the alter-
nating current wave which corresponds very closely in every case
with this critical value. It is well known that since secondary ioni-
zation depends only on the velocity of the ions and thus on the
electric intensity, it should within wide limits be independent of
the number of ions already existing in the gas. The corona stops
sharply on the descending side of the voltage wave showing that
the copious ionization present during the existence of corona does
not aid it in persisting to a lower voltage than that at which it
starts. The presence of a greater or less amount of free or spon-
taneous ionization in the atmosphere has been advanced by some

191 1.] WHITEHEAD— HIGH VOLTAGE CORONA IN AIR. 395

writers to explain the discrepancies, among different observers, in
the voltage at which the corona starts. The foregoing facts seem
fairly conclusive that this supposition is not correct. In order,
however, to further remove doubt on this point a simple experiment
was performed in which the air surrounding the conductor was
ionized from an independent source. A clean polished wire 15 cm.
in diameter was stretched vertically along the axis of a cylinder 17.5
cm. in diameter and about 120 cm. long, made of woven wire with a
I cm. mesh. The high voltage was applied between them, the wire
cylinder being also connected to ground. A large Rontgen ray tube
was enclosed in a light-tight box and placed close to the cylinder.
When this tube was excited a crude electroscope placed 20 or 30
cm. on the other side of the cylinder was immediately discharged
showing that the air of the neighborhood was strongly ionized. In
the darkened room the starting of the visible corona on the wire
could be located readily and the corresponding voltage determined
by successive trials within an error of two or three tenths of one
per cent. By the use of independent observers it was established
without doubt that the presence of the Rontgen ray tube caused
no variation in the value of voltage at which the corona starts.

The general influence of a decrease in pressure or an increase in
temperature toward a lower critical voltage is quite consistent with
the ionization theory. For under the kinetic theory of gases the
free paths of the vibrating molecules and ions are lengthened in
these two conditions. During the free path or interval between
collisions the ions are acted on by the electric force, and the longer
the interval the greater the velocity acquired and the more kinetic
energy and ionizing power. Hence a given amount of energy
will be acquired at a lower voltage if the free path is lengthened.

The lowering of the critical voltage by an increase in frequency
is not to be explained so simply. However if within the molecule or
atom there are a number of electrons in motion or free to move,
and there is some indirect evidence to this eft'ect, it is evident that
the forced vibrations set up by an external alternating field will,
with the increasing frequency of these vibrations, cause the mutual
attractions within the structure of the atom to become less and less
strong, and therefore more liable to be broken when in collision

396 WHITEHEAD— HIGH VOLTAGE CORONA IN AIR. [April 21,

with an extraneous ion. It is surprising however that this effect
should be noticeable at frequencies so low as 60 to 90 cycles, for
tliey are incomparably slower than those suggested by theory for
tlie vibrations within the atom. The close relation between the
first appearance of corona and the peak or maximum of the voltage
wave is natural in the light of theory, for at atmospheric pressure
the mean free path of an electron is about 6 X lO"^ cm. long, and
under a field sufficiently strong to ionize this path is traversed in
about 2 X lO"^- seconds.

Perhaps the most interesting problem in connection with the
phenomenon of corona formation is the explanation of the greater
values of electric intensity required to start corona around smaller
wires, i. e., the upward trend of the curve of Fig. 2. Why should the
properties of the air change with a slight alteration in the size of a
conductor whose diameter is fifty thousand times as great as the
mean free path of a molecule? No tenable explanation has been
ofifered. The attraction to the conductor of oppositely charged
ions which pile up as it were and reduce the actual gradient below
that calculated, and at the same time increase the gas pressure, has
been suggested. Both suppositions immediately include an in-
fluence on corona voltage of the amount of ionization already
present, and this as already noticed is contrary to observation.
Simple calculation also will show that the charge sufficient to mate-
rially reduce the gradient at the surface of a conductor at corona
potential would require a number of ions far in excess of the num-
bers commonly present in the atmosphere. The writer by a sensi-
tive optical method could find no indication of an increase of pres-
sure at the surface of the conductor. It appears probable that the
explanation will be found in the decreasing surface of the smaller
conductors. Secondary ionization probably begins with the col-
lisions of a few electrons which have free paths longer than the
average. With decreasing area of conductor, the number of neigh-
boring electrons whose free paths exceed a certain length, and at
the same time are subject to the maximum electric intensity, will
be decreased, and consequently the corona forming electric intensity
must be higher.

Johns Hopkins University,
April 20, 1911.

DISRUPTIVE DISCHARGES OF ELECTRICITY THROUGH

FLA^IES.

By FRANXIS E. XIPHER.
{Read April 21, 1911.)

In a paper published by the Academy of Science of St. Louis^
the author pointed out the essential difference in character between
the eft'ects of X-rays in the ionization of air and that produced in a
column of air exposed to the positive terminal of an influence
machine.

The action of X-rays is to dislodge negative corpuscles from
some of the air molecules and load them upon others. Such a mass
of air is said to have the property of conduction. Some of the mole-
cules in it will accept negative corpuscles from those to whom they
have delivered them or from the terminal of a negatively charged
electrometer. Other molecules will deliver their overload of nega-
tive corpuscles to an electrometer terminal from which negative cor-
puscles have been drained, or to the molecules which they have robbed.
If left to itself such a mass of air soon loses its property of conduc-
tion. The average corpuscular charge of a molecule in such a mass
of air is the normal amount.

In a mass of air which forms the positive column due to the
action of an influence machine the negative corpuscles have been
drained, or are being drained into the positive or exhaust terminal.
In air of ordinary pressure it is found that in air thus drained of
negative corpuscles, a disruptive discharge dift'uses into the drained
region. The disruptive channel widens and apparently ceases to
have a disruptive character within the region thus drained. In a
few cases the disruptive channel has re-formed on the other side
of such a cloud-like mass which had apparently drifted over the
photographic plate and away from the positive terminal.

^ Trans., Nos. i and 4, Vol. XIX., and Xo. i, Vol. XX.

397

398 XIPHER— DISRUPTIVE DISCHARGES [April 21,

An illustration of this action is shown in Fig. i. A photographic
plate had the heads of two pins resting upon the film. They formed
the terminals in a gap in a discharge line from the negative terminal
of an eight-plate influence machine to ground. Between this gap
and the machine was another gap of about i mm., which was at the
large knob of the machine.

In order to produce the effect shown in the figure, the machine
was turned very slowly for several minutes. Small discharges
occurred at the small gap. When there was danger of a spark be-
tween the pin-heads, the machine was stopped for twenty or thirty
seconds and then continued. This resulted in draining the negative
corpuscles from the air around the grounded pin-head. A progres-
sive elongation of these drainage lines was examined in a series of
plates in which this operation was continued for an increasing time
interval, the plates being then developed.

In Fig. I after continuing the slow driving of the machine for
about three minutes, its speed was then suddenly increased and a
disruptive discharge passed over the photographic film between the
pin-heads.

This plate is one of many hundreds that have shown this phe-
nomenon of a diffused conduction in the region around the positive
end of the disruptive channel. This channel began at the negative
pin-head, in the midst of the negative glow. That region was not
in a condition of conduction for the negative discharge, and has not
been in any case observed. Fig. i is one of a few cases where the
discharge wandered considerably from the line joining the pin-
heads. In some cases the plate was in the positive line. In some
cases the two pin-head terminals were directly connected to the
positive terminals of the machine with minute gaps at the machine.
In all cases the diffusion area was formed at the positive pin-head
terminal. In all cases the appearance shown in Fig. i was observed.
The appearance is that which might be caused by a volley of nega-
tive corpuscles discharged from the end of the disruptive channel,
and aimed at the pin-head forming the positive, in this case the
grounded, terminal. The pin-head shielded that portion of the film
which was behind it and in line with this discharge from the fog-

I9I1.J OF ELECTRICITY THROUGH FLAMES. 399

ging effect observable around it. The air-film which carried the dis-
charge was in close contact with the film, as is shown by the char-
acter of the shadow. The lowest part of the rounded pin-head only
was effective in this shielding of the film, as is shown in Fig. i.

The interior of the disruptive channel is also a drainage or con-
duction channel. It is in a highly rarified condition, approaching
that of a vacuum tube. The discharge w'hich passes through it is
in the nature of a cathode discharge. The air molecules which form
the stepping stones for this conduction discharge are urged in the
opposite direction from that in which the corpuscular discharge is

Fig. I.

passing. This is incidental to the fact that the conductor is in gaseous
form. These air molecules have in some cases produced effects at
the negative terminal, similar to those shown in Fig. i. They are,
however, less marked in character. They are in the nature of
" canal rays," as observed in a vacuum tube. A photographic plate
showing such effects was reproduced in a former paper.- In a
copper wire the transfer from atom to atom likewise occurs. There
the atoms cannot yield, they are nearer together, and the phenomena
of conduction are much more simple.

' Trans. Acad, of Sci. of St. Louis, Vol. XIX., No. 4, plate XXII., Fig. A.

400

XIPHER— DISRUPTIVE DISCHARGES

[April 21,

An attempt was made to compare the conduction-properties of a
drainage column of air like that shown in Fig. i, with those of the
flame of a blast lamp. Fig. 2 shows a camera photograph of dis-
ruptive discharges between a red-hot ball of iron hung on a wire
suspension by means of which it was grounded, and the negative
terminal of the influence machine. The ball was heated by a blast
lamp, the air being fed from a tank at about two atmospheres pres-
sure. A similar flame was ]')laced between the hot ball and the nega-

FlG.

tive terminal, so that the discharges passed through it. On account
of the long exposure, the contrast between the flame and the indi-
vidual sparks is not very distinct. Some of the sparks show a par-
tial photographic reversal. The discharge lines are, however, all
more or less clearly visible within the flame. Fig. 3 shows a single
spark, made under the same conditions, although the flame was
exposed for nearly half a minute before the spark passed. Fig. 4
shows a similar photograph in which the exposure to the flame was
not over half of a second. There are two discharge lines visible,

igii.]

OF ELECTRICITY THROUGH FLAMES.

401

although only one discharge could be distinguished by the sound.
The fainter discharge came from the red-hot ball, and crossed the
track of the brighter spark, which came from a hook serving for
suspension of the ball on a grounded wire. The track of the fainter
spark is as sharply defined within the flame as that of the brighter
one. In Figs. 3 and 4 the discharge was in the positive line. The
hot ball was grounded.

Fig. 3.

It is evident from these results that the conduction of the gases
within the flame of the lamp is very much less than is shown in the
positive column near the anode terminal in Fig. i. In that figure,
the air within the disruptive channel is highly rarefied. This channel
is a hole bored through the air. The discharge through this channel
issued from the end and continued as " sheet lightning " across the
drainage area surrounding the grounded anode. This drainage area

PROC. AMER. PHIL. SOC, L. 200 Z, PRINTED AUG. 5, I9II.

402

NIPHER— DISRUPTIVE DISCHARGES

[April 21,

is not in the rarefied condition which exists within' the disruptive
spark channel. This part of the discharge must be practically noise-
less. The sound produced by the spark is caused by the collapse of
the spark channel in a manner similar to that caused by the crack
produced by the end of a whip-lash, which also cuts a hole in the
air. When an electrical discharge occurs between clouds or between

Fig. 4.

a region containing an excess and one having a deficiency of elec-
trical corpuscles, the latter region must be in a condition like that
surrounding the grounded anode in Fig. i. The disruptive channel
will dififuse into it. This region is one which is properly called a
region of conduction.

The other end of the discharge channel must penetrate regions
where the air is super-charged with corpuscles. It is not in the

I9II-] OF ELECTRICITY THROUGH FLAMES. 403

same sense a region of conduction. Here tributary discharge chan-
nels will form. These discharge channels branch out from the main
channel and elongate in a direction opposite to that in which the
corpuscular stream is flowing. This end of the discharge is called
forked lightning. Probably in most cases the ends of the discharge
are hidden by clouds.

Fig. I is a reproduction of the original plate. Figs, 2, 3 and 4
are reproductions of photographic reversals of the originals.

404

TRELEASE— THE DESERT GROUP NOLINE^. [April 21,

Distribution of Nolineae

THE DESERT GROUP NOLINE^.
(Plates I-XVII.)

By WILLIAM TRELEASE.
(Read April 21, 1911.)

History.

The four genera NoUim ( Michaiix, 1803), Dasylirion (Zucca-
rini, 1838), Bcaucarnca (Lemaire, 1861 ) and CaUbanns (Rose, 1906)
form so natural a group that many botanists have considered a
single generic name, Dasylirion, suf^cient for all, though they differ
enough in fruit to have caused the founder of this genus to question
the propriety of including in it all of the species that were known
even in his day ; and they show marked differences in habit.

Except that Dasylirion was based in part on a Hcchtia, which
led its author — who later recognized the error — to place it among
the Bromeliacese. and that on his suggestion it has been connected
transiently with the Juncace?e, this genus and its immediate rela-
tives have been accorded place generally among what are now con-
sidered as Liliaceffi, — though not always under that family when its
rather heterogeneous components have suft'ered temporary segrega-
tion. Xo better arrangement has been found than that of Engler
and Prantl'^ who locate the Nolinese between Yuccese and Dra-
cseneas as part of the Draceanoid Liliace^e. From the Yuccese they
are sharply differentiated, among other characters, by their small
polygamo-dioecious flowers (never 10 mm. in diameter), few-
ovuled pistil, and small usually indehiscent fruit rarely more than
one-seeded : and the Dracaenese differ from them in a usually some-
what gamophyllous perianth, perfect flowers, and prevailingly
fleshy fruit, — but in all of these respects the group of Dracasneae
offers a good deal of latitude.

-105

406 TRELEASE— THE DESERT GROUP NOLIXE.E. [April 21,

Distribution and Origin.

Like the Yuccese, the Nolineae are all North American, and they
are comparably distributed except that none are known from the
West Indies. They are among the characteristic plants of the dry
temperate backbone of the continent. None extend north of
southern Colorado, and no species is known to have a very extended
range. Their focal center is evidently the temperate ^Mexican
tableland, on which the genera are all represented and to which the
majority of their species are confined, Bcaucarnca alone, in its most
typical form, being characteristic of the hot country and ranging
into Central America. Of the two genera that reach the United
States, Nolina only enters into the Californian flora, and that only
in the southern desert. Though unrepresented in the intermediate
region, from which it may be assumed to have disappeared, this
genus also appears in the South Atlantic states, apparently as an
ofifset from the grass-leaved Texan stock, rather than indicating its
primal home {map).

The ontogeny of the group is scarcely more than a matter of
speculation. No reason is apparent for considering it to be very
ancient. Though evidently related to the typically septicidal
Yucccc-e, it seems rather more likely to have had a closer evolutionary
connection with the typically loculicidal Dracsenese. More satis-
factory hypotheses may be held concerning the affinities of the
component genera. Nolina may be taken as most closely approach-
ing the prototype of the group because of its extensive range, large
number of species composing differentiated groups, and conformity
to the liliaceous plan in its 3-celled pistil and cotyledonary arch.
Calibaiins appears to be an offset of Nolina. Beaucarnca and
Dasylirion, with a single-celled pistil, may represent parallel off-
shoots from Nolina or a no-longer recognized derivative of that
genus ; and the question may be raised whether Bcaucarnca is more
than a well-marked subgenus of Dasylirion which, strictly limited,
itself consists of two quite dissimilar groups. These affinities may
be indicated as follows : '

T.T /Calibanus.

Nolina/

\//Beaucarnea.

^Dasvlirion.

191 1.] TRELEASE— THE DESERT GROUP X0LIXE.5:. 407

Biology.

All Xoline?e are perennial, and, as would be expected from their
habitats, they are pronounced xerophytes with a rather succulent
caudex," either small and insignificant or moderately developed, and
then either prostrate or erect, or even of tree size (/>/. 1-4), and
rather hard usually rough-edged or even prickly leaves^'*^ covered by
a well-cuticularized epidermis, the stomata usually arranged in lines
overlying the parenchyma between strong fibrous bundles and
either furnished with an outer vestibule as in Agave, etc. (Dasyli-
rioii), or located between prominent ribs that, especially in NoUna,
are often covered with more or less interlocking papillae.^^-^*' They
occur most strikingly in suth desert associations- as count Agave,
Yucca and Hcchtia among their characteristic components {pi. 2,4).
In many species the tip of the leaf shreds into a sometimes brush-
like bunch of fibers, and in one (Nolina Bigelovii) the margin
breaks away sparingly — in kind, rather than quantity, recalling the
fibrous exfoliation characteristic of many yuccas and of one large
group of spicate agaves. From a study, of the leaf-tip of Dasylirion
acrotriche, Zuccarini-* was led to believe that what passes for the
leaf is really a petiole with ventral ligule, the blade, considered as
peltate, being represented by the more dorsal shreds only. The
prevalent dorsal insertion of the haustorium on the cotyledonary
sheath in seedlings of this group is worthy of note in connection
with this opinion (pi. ij).

Though sometimes weakened or even destroyed by flowering
under cultivation, all of the Xolineae appear to be normally poly-
carpic. The terminal inflorescence^--* is essentially of one type
though varied from a thin lax raceme-like wand into a stout com-
pound spike with short and broad divisions or an open simple, com-
pound or even decompound panicle (pi. 5). Whatever its form,
the flowers are clustered, usually two or three together, in the axils
of small prevailingly denticulate bractlets, either on cushions so
short that they appear to come from the main axis, or, more com-
monly, on evident secondary or tertiary branches (pi. 6, 7). The
primary branches appear to be 8-ranked^' and the bracts are often
large and conspicuous, those which support the ultimate flower
clusters being scarcely larger than the bractlets.

408 TRELEASE— THE DESERT GROUP NOLINE^. [April 21,

The sometimes slightly fragrant^^ polygamo-dioecioiis flowers
are borne on slender pedicels never greatly exceeding their own
length, which are always distinctly jointed, usually about the
middle. Though the flowers are small, their at first petaloid, then
scarious-persistent distinct entire or toothed segments are usually
whitish, though more or less tinged with green, violet, rose or
cream — a coloration supported by the usual whiteness of the scari-
ous bractlets and, often, by similarly colored large bracts. The
small elliptical anthers are introrsely versatile, their filaments
slightly adnate to the base of the perianth segments. Three connate
carpels, with typically two anatropous basal ovules each, constitute
the pistil which is i- or 3-celled in different genera. The stigmas
are essentially apical, on more or less free and divergent style tips in
Nolina, crowning the rather narrowed ovary in Beaiicarnea, along
the rim of a distinct funnel-like though sometimes cleft style in
Dasylirion, or as sessile points in Calibaiins (pi. 8).

Essentially unisexual and often dioecious, the flowers are perfect
in plan ; and abortive stamens are found in the fertile flowers, and
more or less recognizable rudimentary pistils in those that are
functionally staminate. In fertile flowers nectar is secreted by small
septal nectar-slits in the base of the pistil, — often very evident after
this has enlarged into a fruit (pi. p) ; and in staminate flowers it is
the rudiments of the carpels that perform the same function.-*

Though prevailingly 3-merous, the flowers may show deviation
from this pattern. Preda^' noted that about one-fifth of the flowers
of a pistillate plant of Dasylirion glaucnm were 4-merous ; and in
examining large numbers of the fruits of this genus I have observed
2-, 4- or 5-winged fruits of several species and one 4-carpellary fruit
of Calibaitus (pi. 11). Several observers have found that partly
developed fruits may occur now and then on staminate plants® ; my
own observation shows that well developed stamens may be found in
some pistillate flowers ; and Bouche^ records the transformation of
staminate into pistillate individuals, — suggesting an interesting line
of study for those who may observe and experiment with these
plants as they grow under natural conditions.

Observations on pollination do not appear to have been re-
corded, but the flowers are clearly entomophilous and their pollina-

191 1-] TRELEASE— THE DESERT GROUP XOLIXE.E. 409

tors are to be sought probably among the Hymenoptera and Dip-
tera, as has been suggested to me for Dasylirion by Sr. Patoni, of
Durango,

Normally fertilized, the ovules develop into 3-sided or 3-grooved
seeds with micropyle by the side of the hilum, a slender often
scarcely discernible raphe, and thin and smooth or somewhat thick-
ened and wrinkled envelopes composed of thin-walled cells and
representing essentially the seed-coats though often with a terminal
umbo or apiculus representing the base of the nucellar tissue. The
bulk of the seed consists of rather firm endosperm through which
the finger-like embryo passes upward from near the micropyle
toward the morphological base of the nucellus. The endosperm
consists of moderate-sized polygonal cells with glistening white
rather thick pitted walls and coarsely granular contents destitute of
starch. The walls of these cells are of the " reserve-cellulose " type,
but they are colored blue by neither iodine nor chlor-iodide of
zinc, though they swell so greatly in the latter reagent that in a
thick section the contents, in which large and abundant oil drops
separate out, promptly extrude, sausage-like, from any chance
break (pi. 10). Went and Blaauw-'- have reported partial embryo
formation in some ovules and much more complete endosperm de-
velopment in others, in a pistillate Dasylirion. — apparently without
concurrence of male nuclei. Usually only one of the six ovules pro-
duced by a normal pistil matures in the i -celled fruit of Dasylirion
and Bcaucarnca or the 3-celled ovary of Calibanus; but with the
3-celled fruit in NoUna, though a single seed is the rule, two or three
are not infrequently seen, — usually only one to a cell, though ex-
ceptionally both ovules of a carpel develop.

The ripened fruit is dry-walled : subglobose with three low ribs
in Calibanus, triangular with strongly developed dorsal wings on
the carpels in Dasylirion and Bcaucarnca, and deeply 3-lobed be-
tween the wingless carpels in Nolina. In the first three genera it
does not dehisce, but in Nolina, though the delicate walls are often
irregularly torn — sometimes even before maturity of the rather
firmly attached seed, or the fruit may remain long unopened — loculi-
cidal dehiscence is more or less prevalent (pi. 11, 12).

If observations on dissemination have been published, they have

410 TRELEASE— THE DESERT GROUP XOLIXE^. [April 21.

escaped my search, but the process may be inferred with some
probabiHty from the character of the fruit. In all. the ripened fniit,
with its enclosed or attached seed or seeds and the persistent but
unenlarged perianth, falls by disarticulation of the pedicel, — close
to the fruit in Dasylirion and Calibaiuis, somewhat further from it
in Bcaiicarnca, and usually at a still greater distance in Nol'ina. No
provision for dissemination other than through rolling or being
blown over the ground appears in the round fruit of Calibanus.
The winged fruits of Dasylirion and Bcancarnca are as evidently
wind-scattered as the similarly disarticulating and equally small
fruits of Rtiiiicx, — though in the latter the wings are not carpellary
but consist of the enlarged persistent sepals. The very different
fruits of Nolina are likewise evidently wind-disseminated, their
more or less inflated carpels giving them a character intermediate
between winged and balloon fruits.

Germination, of which no published records have been found, is
of Klebs' Asphodelus-Tradcscantia type.^"--'^' the seed — freed from
the remnants of the fruit in NoVuia or still contained in them in the
other genera — remaining in the ground with the arched haustorium
elongating with the cotyledonary sheath so as to reach a length of
even 10 mm. InKoVuia longifolia and in specimens of N .parviflora
preserved by Dr. Rose, the haustorium is apical, though a slight
elbowing is sometimes seen near the the top of the arch ; and it
sometimes straightens and lifts the seed from the ground. Seed-
lings of Bcaiicanica and Calibaints preserved by Dr. Rose show that
in these genera the sheath is produced above the arch in form of a
pointed ventral ligule, as is true in such species of Dasylirion as I
have observed. In these cases the haustorium appears to be dis-
tinctly dorsal on the sheath, along which it is often sharply re-
fracted (pi. i^-ij). Initial growth is evidently at the princii)al
expense of the granular protoplasm, oil and " reserve-cellulose " of
the endosperm. In Calibanus and Bcancarnca, as is shown in excel-
lent specimens in the National Herbarium prepared by Dr. Rose, the
formation of the thick trunk follows germination quickly.

191 ■•] TRELEASE— THE DESERT GROUP XOLIXE.^. 411

Uses.
Though none of the XoHnese can be considered as of great
present economic importance, many of them are utilized in one
way or another and it is probable that more use can be made of
some species than is now the case. In the great bend of the Rio
Grande I have seen the trunks of Dasylirioii split open to give stock
access to the rather watery pith ; and they are sometimes cut for
feeding.-'"'-^ In Mexico the trunks of Dasylirion are roasted and
eaten similarly to those of the mezcal agaves ; and Dr. Gregg notes
a similar use of a Xoliiia on the label accompanying a specimen of
it. From such roasted trunks of Dasylirion, after fermentation, an
alcoholic beverage very similar to mezcal spirits is distilled, and
under the name of sotoP--^^'^*--^ it is very commonly used through
the extensive ^Mexican territory over which this genus occurs. As
in Yucca, Agave, and .some other plants, the sap of those now under
consideration contains, as a water conservation provision, a saponi-
fying substance, and the roots of Xolina Pahncri are said to serve
as an amole.^^ The leaves of Dasylirion and Nolina — and presum-
ably of Beaucarnca — are used for thatching,^^ basket work, coarse
hats and similar plaited-ware, either entire or shredded. ''•^-'^^
Though less employed than that of yuccas and agaves, their fiber is
also somewhat used locally, and the narrow leaves of the eastern
bear-grass have long been used in their entirety for hanging meat
and similar domestic purposes for which strength rather than
finished cordage is needed. Some thought seems to have been given
also to the preparation of paper pulp from the fiber of Dasxlirion.^

SvsTEM.VTic Revision.
In revising the forms known to me I have had the privilege of
seeing an unusual amount of typical material, for which I am greatly
indebted to Professor Radlkofer of Munich (Zuccarini types), Dr.
Robinson of Cambridge (Watson types), Dr. Rose of the National
Herbarium (types of his own species) and Mr. Brandegee of
Berkeley, whose collection contains numerous critical forms. Ow-
ing to Engelmann's early interest in the vegetation of the Texano-
Mexican region, his herbarium, now at the Missouri Botanical

412 TRELEASE— THE DESERT GROUP XOLIXE.^. [April 21,

Garden, is rich in representatives of this, as of other groups char-
acteristic of that arid region, — as herbarium representation of such
plants goes : and in it, as well as in the herbarium of the New York
Botanical Garden and in the National Herbarium, have been found
types or cotypes of the species of Scheele and Torrey.

I do not venture to think that anything like the last word
on the group is here said, — the sparse occurrence of the representa-
tives of admitted species through a vast and greatly diversified area,
as shown by the distribution map, would speak against such a view ;
but the following rather tersely cast synopsis is published in the
hope that it may render the work of filling gaps in both range and
forms easier than it has proved in the past. Space is not taken for
a full bibliography, — though this would not have been very exten-
sive; but the principal revisions of each genus are noted, as well as
the various names under which a species has appeared ; and refer-
ences are given to all illustrations that have been found.

Synopsis of Genera.

Ovary 3-celled. Fruit wingless.

Fruit deeply 3-lobed, often inflated : seed nearly globose, rather fleshy-
walled. Pedicels articulated rather far below the flowers. Perianth
segments entire, papillate-pointed. Leaves strongly ribbed with usually
papillate grooves, at most serrulately roughened on the margin. In-
florescence a panicle (or racemosely reduced). Nolina.

Fruit globose-triangular, not lobed or inflated ; seed melon-shaped, thin-
walled, occluding the sterile cells. Pedicels articulated close to the
flowers. Perianth segments nearly entire, rounded. Leaves as in Nolina.
Inflorescence a panicle. Calib.^nus.

Ovary i-celled. Fruit 3-sided and 3-winged, not lobed or inflated.

Pedicels articulated somewhat below the flowers. Perianth segments
entire, acute. Seeds 3-grooved or 3-lobed. Leaves somewhat ribbed,
the grooves not usually papillate, at most serrulately roughened on the
margin. Inflorescence a panicle. Beaucarnea.

Pedicels articulated close to the flowers. Perianth segments denticulated,
rather obtuse. Seeds 3-grooved or 3-sided. Leaves not ribbed, their
margin (in al] except one sc|uare-leaved species) armed with strong
prickles and usually also serrulate-roughened. Inflorescence a stout
compound spike. Dasvlirion.

NoLIXA.
Michaux, Fl. P.or.-Amer. i: 208. 1803. — Watson. Proc. Amer.
Acad. 14: 246-8. 1879. — Rose, Contr. U. S. Nat. Herb. 10: 92.

19"] TRELEASE— THE DESERT GROUP XOLIXE.^. 413

1906. — Sometimes merged in Dasylirioii or Bcaucarnca, and made to
include the latter genus by Hemsley, Biol. Centr.-Amer. 3: 371,
which is conformed to the views of Bentham and Hooker, Gen.
Plant. 3 : 780. — -At first monotypic, based on .V. gcorgiana.

Leaves thin and grass-like (but hard-fibrous), linear, rarely over 5 mm. wide,
rather flat, usually not brush-like at tip. Bracts not very showy.
Acaulescent (pp. 413-416). Gr.\minifolle.

Inflorescence commonly as long as the minutely serrulate-scabrous
essentially green spreading leaves, peduncled, unbranched or with
slender usually simple branches 15-25 cm. long. Floriferous bracts
small, not imbricated. Pedicels remaining filiform, increasing to
8 or 10 mm. and equaling or exceeding the usually rather large
and inflated fruit. Seed not prominently exposed.
Leaves smooth and rather open between the ribs. Panicle not com-
pound. Lower bracts much shorter than the subtended branches.
Bractlets barely serrulate.

NoLiNA GEORGiANA ]Michaux, Fl. Bor.-Amer. i : 208. 1803. —
]\I(asters), Gard. Chron. n. s. 15: 688, 697. /. 126.
PlwlaiigiiDii zirgatuui Poiret in Lamarck, Encycl. Meth. 5: 246.
1804.

Leaves 3-5 mm. wide. Liflorescence simply pani-
cled with rather spreading branches. Flowers rather
'"^ large. Fruit subelliptical, rather pointed, 7-9 X 8-
10 mm. Seed 2X4 mm.- — PI. 5, 11.

Central South Carolina and across central Georgia.
Specimens examined: Georgia. Milledgeville (Boykiii, 1836).
Augusta (Cuthbcrt, 1877). Belair (Eggcrt, 1899). Big Lott's
Creek (Harper, Qd^, igoi). Columbia County iChapiiian) . Thom-
son (Bartlctt, 11/ 4, 1907).

N. AT0P0C.\RPA Bartlett. Rhodora. 11: 81. 1909.

Leaves 2-4 mm. wide. Inflorescence unbranched or /-r~\

simply panicled. Fruit more or less unsvmmetricallv ] / sL^
obovate, shallowly notched, or pointed, scarcely inflated, 4i' ' ^ J
5X6 mm. Seed 3X4 mm. ""'" """^

Eastern Florida.

Specimens examined: Florida. Eau Gallic (Ciirtiss, 3702,
1896, — the type; 2Q^/). Without locality (?Riigc}. 124, 1842-9;
Chapfiiaii). Tacoi {Palmer, j66, 18/4: Garber, 18/6) . Tampa Bay
(Burrozi's).

414 TRELEASE— THE DESERT GROUP XOLIXE^. [April 21,

Leaves (as in all except the two preceding) with the sides of the
ribs microscopically papillate. Lower bracts sometimes about
equaling the subtended branches. Bractlets toothed. Fruit (as in
all except the two preceding) conspicuously notched.

N. Brittoniana Na.sh, Bull. Torr. Bot. CI. 22: 158. 1895.

Leaves 5-10 mm. wide. Inflorescence simply pani-
cled with rather erect branches. Fruit depressed-
orbicular, 8 X 10 mm. Seed 3X4 nim.

North-central Florida.

Specimens examined: Florida. Eustis (Nosli, ^^q, 1894, — the
type; IVcbbcr, 406, 1896). Clermont C^MacEhi'ce, 1895; Williaiii-
son. with the close-ribbed leaves of this species, but fruit rather of
gcorgiaiia) .

N. LiNDHEiMERiANA Watsou, Proc. Amcr. Acad. 14: 247. 1879.

Dasylirion Lindheimerianum Scheele, Linnsea. 25: 262. 1852.

D. tcnuifolinui Torrey, Bot. Alex. Bound. 215. 1859.

Bcancarnca Liiidhciincriana Baker, Journ. Bot. 10: 328. 1872.

Leaves 2-5 (exceptionally 9) mm. wide. Inflores-

'^i^r'i^^/^ cence simply panicled with spreading branches often

^ ^:^~h^ less than 10 cm. long, or the lower of these with

( J^ slender branchlets less than half as long. Fruit some-

j\ "K-^yX what depressed-orbicular, 7-8 X 8-10 mm. Seed 2X3
mm. — PI. 12.

Central Texas. — In the region of .V. tc.vaiia and Dasylirion
tcxannm.

Specimens examined: Texas. Vicinity of New Braunfels
{Lindhcimcr, 21^, 1846, — the type of D. Lindheimerianum; ^51,
552, 1846; 1 21 4-1 2 1/, 1849). Sabinal River {Wright, 1919, 185 1-2,
— the type of D. temiifoUum). Austin {Hall, 634, 1872) . Bandera's
Pass {Revcrchon, 1606, 1884). Cherry Spring (Jenny, 831).
Edwards County {Hill, S9, 1895). North of San Antonio (Hast-
ings, 81, 1910). — Gillespie County (Jcrmy, — with leaves 4-9 mm.
wide). Western Texas {Wright, 6/ 3, 1849).

Inflorescence rather dwarf, panicled. Bractlets rather conspicuous, more
or less lacerate. Leaves glaucescent, raggedly serrulate-scabrous.

igii] TRELEASE— THE DESERT GROUP XOLIXE.^. 415

Pedicels rather slender, at length equaling or exceeding the fruit.
Floriferous bracts not imbricated.
Lower bracts linear, leaf-like. Panicle simple.

N. PUMiLA Rose, Contr. U. S. Xat. Herb. lo: 92. 1906.

Leaves 2-4 mm. wide. Inflorescence 30 cm. long,
the upper two-thirds narrowly and simply panicled
with short weak branches scarcely 2 cm. long.
Fruit suborbicular, 6-7 mm. in diameter, the pedicels
somewhat thickened upwards. Seed (immature)
2X3 nim.
West-central Mexico.

Specimens examined: Tepic. Sierra Madre ]^Iountains near
Santa Teresa (Rose, 216=^, 1897, — the type).

Lower bracts dilated and scarious. Panicle compound.

N. H.\RTVVEGiANA Hemslcy, Biol. Centr.-Amer. 3: 371. 1884.
Cordyliiie longifolia Bentham, Plant. Hartweg. 53. 1840.
Rouliiiia longifolia Brongniart, Ann. Sc. Xat., Bot. ii. 14: 320.

1840.
Dasylirion junccum Zuccarini, Abhandl. Akad. Miinchen. CI. II.

4 (=Denkschr. 19) : 19. 1845.
D. HartwegiaiiKiii Zuccarini, /. c. 21. 1845. — Bentham, /. c. 348.

1857-

Beaucarnca Hartzccgiaiia Baker, Journ. Bot. 10: ^2j. 1872.

Shortly caulescent? Leaves 3-4 mm. wide, somewhat fibrous-
shredding at tip. Inflorescence 25-50 cm. long, short-stalked, ovoidly
compound-panicled with pyramidal divisions 8-15 cm. long and short
stifiish branchlets. — PL 16.

Central [Mexico. Collected aboitt Zacatecas by Hartweg in 1837.

The characters are extracted from the descriptions of Zuccarini

and Baker and from a photograph of a Hartweg co-type (406) in

the Delessert herbarium which I owe to the obliging kindness of

M. de Candolle and reproduce here with his permission.

Pedicels thickened, about half as long as the rather large fruit.
Floriferous bracts imbricated. Panicle simple, scarcely half as
long as the leaves.

N. HUMiLis Watson, Proc. Amer. Acad. 14: 248. 1879. — Hemsley,
Biol. Centr.-Amer. 5. pi pj.

416 TRELEASE— THE DESERT GROUP XOLIXE.-E. [April 21,

Bcaiicanica hitiiiilis Baker, Journ. Linn. Soc, Bot. 18 : 237.

Leaves 2-;^ mm. wide. Inflorescence 15 cm. long,
with a few suberect basal branches one-third as long.
Fruit suborbicular, 7X9 mm., scarcely inflated. Seed
very large, 3-4 X 5 mm., prominently exposed.

East-central Mexico. In the region of A^ JVatsoiii, Calibanus,
and Dasylirion Parryanum and graminifolium.

Specimens examined: San Luis Potosi. Vicinity of San Luis
Potosi {Parry & Palmer, 8/j, 1878, — the type).

N. Watsoni Hemsley, Biol. Centr.-Amer. 3: 372. 1884; 5. pi. p-/.
Beaucarnca JVatsoiii Baker, Journ. Linn. Soc, Bot. 18: 236.

1880.

Leaves 5 mm. wide, rather concave and unusually rough-margined.

Inflorescence 25-30 cm. long, with rather numerous

^ /"T^^ strict branches scarcely one-third as long, smooth or

© vJv/y somewhat scabrid on the short peduncle. Fruit more

or less ovate-orbicular, cordately notched, 8 X 8-10
mm., inflated. Seed (immature) 2X3 mm.
East-central Mexico. In the region of A^ humilis, etc.
Specimens examined: San Luis Potosi. Vicinity of San Luis
Potosi {Parry & Palmer, 8/4, 1878, — the type, 502, 1878; Schaffner,
261, 1879).

Leaves rather thick, Hnear or narrowly oblong-triangular, scarcely over 12
mm. wide, green, more or less concave and unequally keeled on one or
both faces, raggedly dentate-scabrous in most species and in age often
fibrous-lacerate at tip. Inflorescence usually about as long as the leaves,
peduncled, compound-panicled. Bracts not usually very showy. Bract-
lets more or less lacerate.
Fruit small, not inflated, the relatively large seed early exposed and
prominent (pp. 416-420). Erumpentes.

Inflorescence (as in the last preceding species) often roughened in
lines. Pedicels rather thickened in fruit. Acaulescent.
Lower bracts' firmly long-attenuate from a somewhat dilated
scarious-margined base.
Lower panicle divisions much shorter than the subtending
bracts, with rather weak strongly ascending branch-
lets.

N. TEXANA Watson, Proc. Amer. Acad. 14: 248. 1879. — Nash,
Journ. N. Y. Bot. Card. 6: 48. /. 16.
Beancarnea te.vaiia Baker, Journ. Linn. Soc, Bot. 18: 236. 1880.

191 1.] TRELEASE— THE DESERT GROUP XOLIXE^. 417

Leaves very narrow, 2-5 mm. wide, smooth-edged or slightly
roughened, from half-round becoming triquetrous.
Inflorescence often much shorter than the leaves, with
oblong divisions often 15 cm. long and lower branch-
lets half as long, or subsimple. Fruit somewhat
depressed, 4 X 5-6 mm. Seed 3 mm. in diameter. — PL 12, 75.

Central Texas. In the region of N . Liiidlicimcriaiia and Dasy-
lirion texanum.

Specimens examined: Texas. \'icinity of New Braunfels (Liiid-
hcimer,550, 1846, 712, 1847, — the types ; 1218, 1849). Austin {Hall,
^35' 1872). Hamilton County {Rcz'erchon, gdy, 1882). Cibolo
{Havard, 1883). Blanco County {Rcvoxlion, mixed with 1606).
Kerr County (Bray, 184, 1899). Davis Mountains (Earlc & Tracy,
J22, 1902). Gillespie County {Jenny, 327). Comstock {Thomp-
son, 191 1 ). Without locality {Buckley).

"v Lower bracts mostly triangular, becoming friable.

Xfi^??t pa^nicle division much shorter than the long-caudate
subtending bract, with rather weak finally ascending
branchlets.

N. affinis Trelease.

Leaves very narrow, 3-4 mm. wide, sometimes smooth-edged.
Inflorescence at length with broad divisions 10 cm. long ^
and lower branchlets scarcely half as long. Fruit de- P" '^^i
pressed, 5 X 6-7 mm. Seed 3 mm. in diameter. •-— ^

North-central Mexico. On the outskirts of the range of A^ ^n<>n-
pens, N. microcarpa and Dasylirion Iciophylluni.

Specimens examined: Chihuahua. Rocky hills near Chihuahua
{Pringle, i, 2, 1885, — the type). Santa Eulalia {Palmer, ijg, 1908;
Rose, 1 16/ 2, 1908).

N. caudata Trelease.

?Noliiia sp. Rose, Contr. U. S. Nat. Herb. 20. pi. 46-8.

Leaves very narrow, 4 mm. wide, somewhat rough-
edged. Inflorescence slender, with narrow divisions
scarcely 10 cm. long and lower branchlets 2-5 cm.
long. Fruit rather depressed, 4 X 5-6 mm. Seed 3

mm. in diameter. — PL 6.

PROC. AMER. PHIL. SOC. , L. 200 AA, PRINTED AUG. 7, I9II.

418 TRELEASE— THE DESERT GROUP XOLIXE.^. [April 21,

Southern Arizona. In the region of iV. microcaypa and Dasy-
lirioii JVJicclcri.

Specimens examined: Arizona. Mule Mountains {Tourney,

1894, — the type). Huachuca Mountains {"^Wilcox, 1892, and 2f,j,

1894; Griffiths, 4831, 1903). Dragoon Summit {'^J\iscy, 1881, —

leaves). Xogales (?Braiidcgce, 1892; Fcrriss, 1902; Coville, 1624,

1903; Tliompson, 191 1). Sierra del Pajarito (?Trclcasc, ^Sy,

1900). Boundary Line (?Parry, Bigclow, Wright & Schott,

1443: Mcanis, 258, 2po, 1892).

Lower panicle divisions more or less equaling the attenuate
"subtending bracts, with rather stiff spreading branchlets.

N. ERUMPEN.S Watson, Proc. Amer. Acad. 14: 248. 1879.

Dasylirioii cntiiipciis Torrey, Bot. Mex. Bound. 216. 1859.

Bcaucarnca crnmpens Baker, Journ. Bot. 10: 326. 1872.

Leaves usually 6-10 mm. wide and very rough-
edged, exceptionally narrower or smooth-edged. In- ^^""""^/^
llorescence with pyramidal divisions 15 cm. long and C^ vC^--*
lower branchlets half as long. Fruit rather depressed, -^ ' '^'^
5 X 5-7 mm. Seed very large, 4 mm. in diameter.

Western Texas and adjacent Mexico. In the region of Dasy-
lirioii Iciophylluiii and D. Whcclcri JVisIicciii.

Specimens examined: Texas. Western Texas {Wright, 1918,
1851-2, — the type of D. crnmpens: 6q2, 1849). Chisos Mountains
{Bailey, jp/,, 1901). Eagle Mountain (Bigcloic, 1852). Eagle
Spring {Hayes, 1858). Podrero {?Schott, 1855). Chihuahua.
Between El Paso and Chihuahua {Ji'isli-cenns, 2ip, 1846).

N. erumpens compacta Trelease.

Leaves almost as in te.vana, sometimes scarcely 5 mm. wide, the
edge either rough or smooth. Intlorescence with very compact ovoid
divisions scarcely 6 cm. long and branchlets about i cm. long.

Extreme western Texas.

Specimens examined: Texas. El Paso {Fcrriss, 1902, — the
type). Sierra Blanca {Trelease, 386, 1900). Sanderson {'fThonip-
son, 191 1 ). ^larathon {Lloyd, 1910). Presidio {Haivrd, 1880).
N. Greenei Watson in herb. Greene, Bot. Gaz. 5 : 56. 1880. — Name
onlv.

19"] TRELEASE— THE DESERT GROUP XOLIXEvE. 419

Leaves 6-7 mm. wide, smooth-edged. Inflorescence
with rather narrow divisions scarcely 10 cm. long and
lower branchlets nearly half as long. Fruit depressed,
4X6 mm. Seed 2 yC ^ mm.
Southeastern Colorado to northeastern Xew Mexico. The north-
ernmost species of the group.

Specimens examined : Colorado. Between the Purgatory and
Apishipa rivers, north of Trinidad (Greene, Jan., 1880, — -the type).
New Mexico. San ^Miguel County (Braiidcgee, 1879). Lincoln
County (Jl'ooton, 6j6, 1897).

Lower panicle divisions considerably shorter than the sub-
tending "bracts, with short stiff spreading branchlets.

N. cespitifera Trelease.

Leaves 6-10 mm. wide, with dorsal as well as
marginal roughening. Inflorescence very rough from
compound tussocks, with narrow divisions 10 cm.
long and lower branchlets scarcely one-third as long.
Fruit nearly orbicular, about 5 mm. in diameter.
Seed ?

Xorth-central [Mexico. On the margin of the range of Dasy-
lirioii ccdrosanuui.

Specimens examined : Coahuila. Battlefield of Buena Vista
{Wislizenus, ^08, 1847, — the type). High dry lands near Saltillo
(Gregg, 81, 1847).

Inflorescence (.as usual in the genus) essentially smooth. Lower
bracts triangular, scarcely equaling the panicle divisions. Pedicels
slender; Acaulescent with one exception.

N. Palmeri Watson, Proc. Amer. Acad. 14: 248. 1879.

Beaiicariiea Palmeri Baker, Journ. Linn. Soc, Bot. 18 : 235.
1880.

Leaves 8-10 mm. wide, serrulate-scabrous. In-
florescence with narrow divisions 15 cm. long and
rather stifif ascending lower branchlets scarcely one
^ fourth as long. Fruit depressed, 4X5 mm. Seed
3 mm. in diameter.
Lower California. (Jverlapping the region of N. Bigelovii and

420 TRELEASE— THE DESERT GROUP XOLIXE.E. [April 21,

A^. Bcldingi dcscrticola. — The type locality is given as Tantillas
Mountains.

Specimens examined: Lower California. Piiion district {Or-
cutt, 77 J, 1882, — determined by Mr. Watson). San Pedro Martir
{Brandcgce, 1893). Paraiso {?Brandcgee, 1890).

N. Palmeri Brandegeei Trelease.

Nolina sp. Brandegee, Proc. Cal. Acad. ii. 2 : 209. 1889.

?A^. Palmcri Brandegee, Zoe. i : 306.

Arborescent. Trunk about 5 m. high, at length few-branched
above. Leaves 7-8 cm. wide, rather glossy, denticulate-scabrous.
Inflorescence with divisions 15 cm. long and lower branchlets about
one-third as long.

Lower California.

Specimens examined: Lower California. San Julio {Brande-
gee, Apr. II, 1890, — the type). Northern Lower California {Orcuit,
July 3, 1885).

Fruit moderate in size, somewhat inflated, the relatively small seed not

protruding if early exposed. Panicle divisions with rather weak mostly

elongated and ascending branchlets (pp. 420-432). I\Iicrocarf.e.

Lower panicle di»-isions more or less equaling the friable triangular

bracts. Acaulescent. Leaves elongated.

N. microcarpa Watson, Proc. Amer. Acad. 14: 247. 1879.

Beaucarnca microcarf-'a Baker, Journ. Linn. Soc, Bot. 18: 236.
1880.

Leaves 6-12 mm. wide, raggedly denticulate-scabrous. Inflores-
cence with often broad divisions 15-30 to even 45 ^_ _ __ __^

cm. long, and lower branchlets — sometimes again

branched at base — half as long or less. Fruit nearly V

as long as the pedicels, depressed, 5 X 7-8 mm. Seed

3 mm. in diameter, attached and exposed after dehiscence of fruit. —

PI. I, 12.

Southeastern Arizona and adjacent New Mexico and Mexico.
Overlapping the region of A', candafa and associated with Dasy-
lirion Whccleri. The type locality is Rock Canon, Arizona.

Specimens examined: Arizona. Rocky Canon {Rothrock, 2j8,
1874). Chiricahua Mountains {Tourney, 1894 : Bliiiiier, 1^16, 1906).

191 ■•] TRELEASE— THE DESERT GROUP XOLIXE^. 421

Santa Catalina Mountains (Pringlc, 1881, 1882, 1884). Santa Rita
Mountains {Pringlc, 1882; Brandcgcc, 1891). Without locality
{Tourney, 44^, 1892). Sun Flower Valley (Girard, i, 1873). Blue
River {Davidson, jj^, 1902). Xew ^Iexico. Santa Rita del Cobre
{Greene, \%^o). Burro Mountains (i?r/^t_v, ^/j, 1881. — fruit; Gold-
man, 1530, 1908). Dog [Mountains {Mcarns, 2Q4, 1892). Lone
Mountain {Mulford, 42/, 42^, 1895). Otero County {Relin &
Jlereck, 1902). Round Mountain {?JVooton, 1905, — very narrow-
leaved, as in tesana). Mogollon ^Mountains {Ritsby, 412, 1881 ;
Metcalfe, 232, 1903). Alimbres River {Metcalfe, 102=,, 1904). San
Luis Pass {Mearns, 186, 1892; IVooton, 1906). Twin Sisters
( ?Blunier, 1905). Silver City ( IBailey, 1906). Big Hatchet Moun-
tains {Goldman, 1341, 1908). Boundary Lixe {Parry, Bigeloiv,
Wright & Schott, 1442). Chihuahua. Colonia Garcia (Toz^nisend
& Barber, yd, 1899). X'icinity of Chihuahua {IPringlc, i^p, 1885;
Palmer, 333, 1908).

N. durangensis Trelease.

Leaves very thin, 7-1 1 or even 20 mm. wide, irreg-
ularly serrulate-scabrous. Inflorescence with broad
divisions at length 15-20 cm. long and chiefly basal
branchlets 10-12 cm. long. Fruit usually considerably
shorter than the rather slender pedicels, more or less

depressed, small, 5-6 X 6-7 mm. Seed 3 mm. in diameter. — PI. 10.
Northwestern Mexico. In the region of Dasylirion durangense

and simplex.

Specimens examined : Durango. Vicinity of Durango (Pfl/;ne'r,

24P, 1896, — the type ; Ochotcrena, 191 1 ; Patoni, 1911). Tepehuanes

{Palmer, 32^, 1906). Chihuahua. Southwestern Chihuahua

{?Endlich, 1162a, 1162b, 1906).

N. ELEGANS Rose. Coutr. U. S. Xat. Herb. 10: 91. /. 6.
Leaves very thin, 12 mm wide, sometimes lanceo-

lately narrowed above the base, serrulate-scabrous.

Inflorescence with broad divisions 10-15 cm. long and

rather few branchlets scarcely half as long. Fruit

about equaling the pedicels, rather large. 7 X 8-10

mm. Seed 3X4 mni.

422 TRELEASE— THE DESERT GROUP XOLIXE.E. [April 21,

Central ^Mexico. In the region of X. Hartwcgiana?
Specimens examined : Zacatecas. Sierra Madre ^lountains
(Rose, 2^g6, 1897, — the type).

Lower panicle divisions considerably longer than the triangular
bracts. Shortly caulescent. Leaves much shorter than the in-
florescence.

N. rigida Trelease.

Anatis rigida Brongniart, Ann. Sc. Nat., Bot. ii. 14: 320. 1840.

Leave.s 4-5 mm., scarcely 10 cm. long, ciliate-scabrotis. Inflores-
cence much surpassing the leaves, sessile, with broad divisions
about 10 cm. long and rather few branchlets scarcely half as long.
Fruit about equaling the slender pedicels, moderate, about 6 mm.
in diameter. Seed 2 mm. in diameter.- — PI. ly.

Mexico? Known only from the unpublished figures of Sese and
Mogiho and Node-veran, which AI. de Candolle has placed in my
hands for study, and of which he has furnished for publication an
excellent photographic copy.

Leaves relatively or actually thin, 15-40 mm. \vide, serrulate-scabrous, not
usually brush-like at tip. Inflorescence ample, often peduncled, com-
pound-panicled or occasionally decompound. Bracts usually dilated
and papery, often showy. Bractlets flmbriate-lacerate, conspicuous.
Fruit large, inflated, the seed not protruded. Trees (with one excep-
tion?) (pp. 422-426). Arborescentes^
Leaves rather thick, little shredded at tip. Pedicels scarcely half as long
as the fruit.

N. Parryi Watson, Proc. Amer. Acad. 14: 247. 1879.

Trunk 1-2 m. high. Leaves almost pungent, rather thick, con-
cave, keeled, 15-25 or ev^en 35 mm. wide, serrulate-
scabrous. Inflorescence with rather narrow divisions
15-30 cm. long and spreading densely flowered
branchlets scarcely 4 cm. long. Flowers large, with
perianth segments 4 mm. long. Fruit very large,
orbicular, deeply notched at both ends, 12-15 "'"'•i- i" diameter.
Seed 3X4 mm. — PI. 5, 12.

Colorado desert. In the region with A'. Bigclovii.

Specimens examined : California. Desert east of San Ber-
nardino {Parry, 1876, — the tyjic). Whitewater {Vascy, 1881, —

19' I.] TRELEASE— THE DESERT GROUP XOLIXE.^. 423

leaf). San Gorgonio Pass (Engcljiiaiui. 1880). San Bernardino
Mountains (Parish, 1879: pio, 1882; ^143, 3163, 1894). San Felipe
{Brandcgce, 1894). Pala (Orcittt). San Jacinto ^Mountains (Hall,
i8ig, 2432, 1901). Arizona. Fort Whipple (Cones & Palmer,
1865). Between Sandy and Bill Williams Forks (Mrs. Stephens,
1902).

N. BiGELOVii Watson, Proc. Amer. Acad. 14: 247. 1879.

Dasyliriou Bigeloiii Torrey, Bot. Whipple. 151. 1857; Bot. Mex.
Bound. 216. 1859.

Bcancarnea Bigelovii Baker, Journ. Bot. 10: 326. 1872.

Trunk 1-2 m. high. Leaves almost pungent, scarcely concave
or keeled, 15-25 mm. wide, often roughened on the surface, the at
first rough margin shredding away in brown fibers.
Inflorescence with rather narrow divisions 15-30 cm.
long and branchlets scarcely 4 cm. long. Perianth
segments about 3 mm. long. Fruit large, orbicular,
deeplv notched at both ends, usually 10-12 mm. but occasionally 15
mm. in diameter. Seed 3X4 mm.

Western Arizona, across the Colorado desert, and into Lower
California. In the region of A'. Parryi and overlapping the ranges
of N. Paliiicri and N. Bcldhigi. A sketchy picture of it, in the
Tinajas Altas, is given by Schott in Emory, Rept. Bound. Surv.
I. pi 59.

Specimens examined: Arizona. Bill Williams Fork (Bigeloz^.',
1853-4. — the type of D. Bigelovii). Union Pass (Palmer, 1870).
Havasupai Canon (Kiiiner, 1900). Gold Road (Mrs. Stephens,
1902). Little ]\Ieadows (Mrs. Stephens, 1902). California.
[Mountain Springs, near the boundary {Parish, 1880; J\isey, 1880;
Mearns, 2980, 3013, 3066, 3146, 1894). Lower California. Can-
tillas Canon (Orciitt, July 8, 1884). Yubay (Brandcgce, 1889).—
Boundary Line. Tule (Mearns, 320, 1894).— Sonora. (?Schott,
1 44 1. — with fruit scarcely 8 mm. in diameter.)

Leaves rather thin, sometimes shredded at tip. Pedicels nearl.v or quite
equaling the fruit.

424 TRELEASE— THE DESERT GROUP XOLIXE.E. [April 21,

N. Nelsoni Rose, Contr. U. S. Nat. Herb. 10: 92. 1906.

Trunk 1-3 m. high. Leaves 30-40 mm. wide,
strongly serrulate-scabrous. Inflorescence with nar-
row ascending divisions 15 cm. long, and branchlets
— chiefly upwards — scarcely half as long. Fruit?

Northeastern Mexico. In the region of Dasylirioii loiigissiiiuiiii.

Specimens examined: Tamaulipas. Mountains near ^liqui-
huana (Nelson, 448^, 1898, — the type).

N. Beldingi Brandegee, Zoe. i: 305. 1890.

N . Bcldingii Brandegee in Bailey, Cycl. Amer. Hort. 3 : 1092.

1901 ; Gard. Chron. iii. 34: 43. /. 18. 1903.
Trunk 3-5 m. high, rather openly branched. Leaves very slightly
glaucous, 15-20 mm. wide. Inflorescence long-
peduncled, narrow, with narrow divisions 50 cm. long
and branches 8-10 cm. long, often again branched
with branchlets 1-2 cm. long. Fruit much depressed,
retuse at base, very large, 8-10 X 15 nim. or more.
Seed large, 4X5 mm.

Lower California. The type locality is mountain tops in the Cape
Region.

Specimens examined: Lower Califorxia. Sierra de San Fran-
cisquito {Brandegee, j8j, 1892 j. La Chuparosa {Brandegee, 1893,
1905)-

N. Beldingi deserticola Trelease.

Subacaulescent with leaves scarcely 50 cm. long, otherwise re-
sembling the type.

Lower California. In the desert association of N. Pahncri and
iV. Bigeloz'ii.

Specimens examined: Lower California. Yubay (Brande-
gee, 1889, — the type).

N. PARviFLORA Hcmsley, Biol. Centr.-Amer. 3: ^J2. 1884.

Cordyline parviflora HBK., Nov. Gen. Sp. i: 268. 1815; 7. pi.

674. 1825.
Draccena pari'iflora Willdenow in Schultes, Syst. 7: 348. 1829.

■911.] TRELEASE— THE DESERT GROUP XOLIXE.E. 425

Ronliiiia Huinboldtiana Brongniart, Ann. Sci. Xat., Bot. ii. 14:

320. 1840.
Dasyliriuiii Hiiinboldfii Kunth, Enum. 5: 42. 1850.
NoUna Altamiranoa Rose. Proc. U. S. Xat. Mus. 29: 438. 1905.
?Bcaiicanica rcciirvata stricta Baker, Journ. Linn. Soc, Bot. 18:
234. 1880. — As to localities cited.

Trunk 2-4 m. high. Leaves 15-20 or 25 mm.
wide. Inflorescence with divisions 25 cm. long and
lower branchlets half as long. Bracts very showy,
nearly 50 cm. long, caudate-attenuate. Fruit very
large, 8-10-12 X 14 mm. Seed 3X4 mm.
South-central Mexico. The type locality is between Hauhtitlan
and Tanepantla.

Specimens examined : Federal District. Above Santa Fe
(Pringlc, 8060, 1899, — the type of -V. Altamiranoa; IJ620, 1905;
Rose & Hay, 3388, 1901 ; Rose & Painter, 86 jg, 1905 ). Rio Hondo
Canon {Priiigle, 6/8/". 1898). Chalchicomula (/. G. Stiiith, 431,
1892). Guadalupe {Boiirgeau, 320, 1865-6). Puebla. Esperanza
(PitrpHs, 821, 1907). \'era Cruz. Limon {?Trelease, 80, 1905).

N. loxgifolia Hemsley, Biol. Centr.-Amer. 3 : t^jt^. 1884.

Yucca longifolia Schultes, Syst. 7: 1715. 1830. — Zuccarini,
Allgem. Gartenzeit. 6 : 258.

Dasylirion longifoliiim Zuccarini, Abhandl. Akad. Miinchen. CI.
n. 3 ( = Denkschr, 16) : 224. pi. i.f.2. 1840; 4 (=Denkschr.
19): 20, 21. — Alorren, Belg. Hort. 1865 : 7,21. pi. 20. — Garden.
II: 291. /. — Gard. Chron. n. s. 7: 493. /. /j, 567. /. go. —
Fenzi, Bull. Soc. Ort. Tosc. 1890: 112. pi. 6. — Rehnelt,
Gartenwelt. 11 : 14. /. — L'rban, Gart. Zeit. 3: 66. /. 20. — Die
Xatur. 34: 340. /. — Murison, Garden. 24: 433. /. — Garten-
flora. 29: 117. /. ; 33: 68. /. — Roezl, Belg. Hort. 33: 139. —
Gerome, Rev. Hort. 83 : 206. /. 82.

RoiiUnia Kan^'inskiana Brongniart, Ann. Sc. Xat., Bot. ii. 14:
320. 1840.

?yiicca Barrancasecca Pasquale, Cat. R. Ort. Bot. Xi^apoli. 108.
1867. — See also Zuccarini, /. c, and Rept. Mo. Bot. Gard.
13: 114-

426 TRELEASE— THE DESERT GROUP NOLIXE.E. [April 21,

Bcancarnca longifolia Baker, Joiirn. Bot. 10: 324. 1872.

Trunk 2-3 ni. high, swollen at base, at length closely few-
branched at top. Leaves 20-30 mm. wide, very long ^
and recurving over the trunk; green. Inflorescence
nearly sessile with divisions 30 cm. long and lower
branchlets scarcely one-fifth as long. Fruit sub-
orbicular or rather depressed, large. 8 X 10-12 mm. Seed 3X4
mm. — PI. 5, 8, 7j.

South-central Mexico. In the region of Dasylirioii scrratifoliiiiii.
The type locality is given as San Jose del Oro by Schultes, on
authority of Karwinski. Roezl gives its occurrence at about 3.000
m. altitude in Puebla. Oaxaca and Mexico.

Specimens examined: Oaxaca. Huachilla (Co;/.c'a///). Puebla.
Esperanza {Pnrpus, 30//, A, ?30/6, l^oyS). San Luis Tultitlanapa
(Purpiis, 4^2, 1907, 5oyg, B, 1908). Cultivated. Munich Botan-
ical Garden, from Karwinski's seed (Radlkofcr^igoi, — semi-typical).
Palermo Botanical Garden {Trclcasc, /, 1905). Bushey House
Gardens {Blake, 1909).

Certain questionable thin- but narrow-leaved forms grown in gar-
dens under this name, or, in a glaucous form, as var. glanca or as
Pinccncctitia ijlauca, appear to be forms of Bcancarnca.

Calibanus.
Rose, Contr. U. S. Nat. Herb. 10: 90. 1906. — Monotypic, based
on the species figured by Hooker for Dasylirinni Hartwcgianu}ii.

Calibanus Hookerii Trelease.

Dasylirium Harfwcgiannni Hooker, Bot. Mag. iii. 15. pi. jOQp.

1859.
D. Hookerii Lemaire, 111. Hort. 6. misc. p. 24. 1859.
D. cacspitosnin Scheidweiler, Wochcnschr. A'erein Befcird. Gar-

tenbau. 4: 286. 1861.
D. Hookcri Lemaire, 111. Hort. 12. misc. p. 52. 1865.
?D. flexile Koch, Ind. Sem. Berol. 1867. Append, i : 5.
Beaucarnea Hookcri Baker. Journ. Bot. 10: 327. 1872.
Calibauns cacspitosns Rose, Contr. IJ. S. Xat. Herb. 10: 90. /. 4.

pi. 2 4- J. 1906.

'91 1-] TRELEASE— THE DESERT GROUP XOLIXE.E. 427

Shortly caulescent. Trunk depressed globose with numerous
crowns of leaves. Leaves rather thin, somewhat concave and keeled,
narrowly linear, 2-^ mm. wide, serrulate-scabrous on the margin,
not brush-like at tip, blue. Inflorescence scarcely 25 cm. long,
^.^-^ shorter than the leaves, verv short-peduncled, simply

Q"^ Ojjv>^ panicled with thin spreading branches 6-8 cm. long,
~~^ ^- or with exceptional very short and few basal branch-
lets. Bracts scarious, much shorter than the subtended branches,
the iloriferous ones and the bractlets inconspicuous, ovate or lanceo-
late, little-toothed. Flowers minute. Perianth segments about i
mm. long. Fruit triquetrously subglobose, 3-ribbed, 4-5 X 5-/ mm.
Seed melon-shaped, 3 X 3-4 mm. — PI. 6, 8, p, 11, 14.

East-central Mexico. The type locality is Real del ]\Ionte.

Specimens examined : Hidalgo. Ixmiquilpan ( Rose, Painter &
Rose, 8pj4, 1905; Pur pus, 1200, 472 5, 1905). Sax Luis Potosi.
San Luis Potosi {Orcutt, 1903; Palmer, 1905).

Beaucarxea.

Lemaire. 111. Hort. 8. misc. p. 57, with plate. 1861. — Baker,

Journ. Bot. 10: 323. 1872; Journ. Linn. Soc, Bot. 18: 233. 1880,

— in both cases including Xolina. — Rose, Contr. U. S. Nat. Herb.

10 : 87. 1906. — Though not monotypic, based primarily on B.

recurvata. and capable of precise definition.

Leaves with essentialh" smooth grooves and nearly smooth margins, thin,
nearly flat, recurved, green. Floriferous bracts rather elongated. Fruit
large, rather long-stalked before falling. Slender trees, about 10 m. high,
moderately enlarged at base. Eueeaucarxea.

Beaucarxea recurvata Lemaire, 111. Hort. 8. misc. p. 61. i pi.
1861. — Gard. Chron. 1870: 1445. /. 2^4: iii. 46: 4. /. ?. —
Deutsch. Gart. Mag. 1871 : 288. pi. — Gartenflora. 28: 210.
/. — Croucher, Garden. 19 : 372. /.

Piiicoiectitia tiiberculata Lemaire, /. c, as synonym.

Beaucarnca tubereulata Roezl, Belg. Hort. 33: 138. 1883.

A'oli}ia rccurz'ata Hemsley, Biol. Centr.-Amer. 3 : 372. 1884. —
Rehnelt, Gartenwelt. 11 : 78. /. — Gard. & Forest. 9: 94. /. —
Fl. des Serres. 18. misc. p. 26. /. — Karsten & Schenck, \'ege-
tationsbilder. i. pi. ^4. — Gerome, Rev. Hort. 83: 207. /. 8^.

A', tubereulata Hort.

428 TRELEASE— THE DESERT GROUP XOLIXEiE. [April 21,

Trunk openly slender-branched above. Leaves 15-20 mm. wide,
1.5-2 m. long. Inflorescence nearly sessile, broadly ovoid-panicled,
decompound with divisions 30 cm. long, lower branches nearly half
as long and branchlets 5 cm. long. Perianth segments 3 mm. long.
Fruit ?

Southeastern Mexico. Noted by Roezl at Paso del Macho and
by Karsten at Sta. Alaria, in the State of Vera Cruz. — The type of
the genus. — Two garden varieties, 'uitcnncdia and rubra, are noted
by Baker, Journ. Linn. Soc, Bot. 18: 234. 1880.

Specimens examined : Cultivated. Palermo Botanical Garden
{Trcleasc, 1905). Missouri Botanical Garden.

B. iNERMis Rose, Contr. U. S. Nat. Herb. 10: 88. /. 2. 1906.

Dasylirion iiicrnic Watson, Proc. Amer. Acad. 26: 157. 1891.

Trunk rather closely few-branched at top. Leaves 12-15 mm.
wide, about i m. long. Inflorescence long-stalked,
narrowly pyramidal-panicled, somewhat decompound
with divisions 30 cm. long, slender lower branches half
as long and few branchlets 3-4 cm. long. Perianth
segments scarcely 2 mm. long. Fruit elongated-
elliptical, 10 X 14 mm. Seed (immature) 2X3 mm.

East-central Mexico.

Specimens examined: San Luis Potosi. Las Palmas (Priiigle,
3108, 1890, — the type of Dasylirion incrnic). San Dieguito
(Palmer, 644, 1905). Vera Cruz. Zacuapam {IPurpiis, 4432,
1907). East of Huatusco (?EiidIich. 1162, 1906). Carrizal
(?Go}d)ua)i, yoS, 1901). — The incomplete Vera Cruz material per-
haps belongs to the preceding, though short-leaved.

B. pliahilis Rose, Contr. LI. S. Nat. Herb. 10: 89. 1906.

Dasylirion pliabilc Baker, Journ. Linn. Soc, Bot. 18: 240. 1880.
Trunk openly slender-branched at top. Leaves 15 mm. wide,
less than i m. long. Inflorescence compound-panicled
with broad divisions 30 cm. long and few rather
short spreading branches. Perianth segments 3 mm.
long. Fruit somewhat ol>ovately round-elliptical. 1 1-
12 X 13-15 mm. Seed 3X4 mm., irregularly 3-
lobed, transversely wrinkled. — PI. 10.

igii.]

TRELEASE— THE DESERT GROUP XOLIXE.^.

429

B

Southeastern ^Mexico.

Specimens examined: Yucatan. Near Sisal (ScJwtt. 892, — the
type of Dasylirioii [^Habile). Progreso {Goldman, do/, 1901).

GUATEMALENSis Rose, Contr. U. S. Nat. Herb. 10: 88. /. i.

1906.
Trunk often with slender multiple stems, variously branched.
Leaves 25-30 mm. wide, less than i m. long, smooth-
edged. Inflorescence short-stalked, broadly ovoid-
panicled, decompound with divisions 30 cm. long,
rather spreading branches sometimes half as long,
and few branchlets 6 cm. long. Perianth segments
3 mm. long. Fruit elliptical-obovate. 13-15 X 15-18 mm., at length
openly notched at top and base. Seed 5 mm. in diameter, irregularly
3-lobed, srhooth. — PL 7.

Guatemala. The southernmost species of the group.
Specimens examined: Guatemala. El Rancho {KeUcrman,
4320, 1905, — the type; 33p8, 1906; /Oij, 1907, and /o^g, 1908).
Cultivated. Guatemala City {KeUcrman, 6o6g, 1907).

B. GoLDMANii Rose, Contr. U. S. Xat. Herb. 12: 261. pi. 20. 1909.

Trunk openly slender-branched above. Leaves 15 mm. wide,
scarcely i m. long, essentially smooth-edged. Inflores-
cence nearly sessile, compound-panicled with narrow
ascending divisions 15-20 cm. long and few strict
branches about half as long. Perianth segments about
2 mm. long. Fruit elliptical, very large, 12-15 X 18-20
mm. Seed ?

Southern Alexico.

Specimens examined: Chiapas. San Vicente {Goldman, 88/,
1904, — the type).

Leaves papillate-grooved as in Xoliiui. rather rough-margined, firm, more or
less concave, keeled or plicate, nearly straight, pale or glaucous. Flori-
ferous bracts short. Fruit small for the genus, ver\- short-stalked. Trees
about ID m. high, greatly swollen at base. Papill,\t^.

B. STRiCTA Lemaire, 111. Hort. 8. misc. p. 61. 1861.
Pinccncctitia glaiica Lemaire, /. c, as synonym.

430 TRELEASE— THE DESERT GROUP XOLINE^. [April 21,

Bcaiicanica rccun'ata stricta Baker, Journ. Linn. Soc, Bot. 18:
234. 1880.

B. glaitca Roezl, Belg. Hort. 33: 138. 1883.

B. Purpusi Rose, Contr. U. S. Nat. Herb. 10: 89. 1906. —
Purpus, ]\I511er's Deutsch. Gartn.-Zeit. 23 : 223. /.

Trunk moderately swollen, irregularly rather few-branched.
Leaves more or less keeled or plicate, 8-15 mm. wide,
scarcely i m. long, the yellowish margin usually
minutely serrulate-scabrous. Inflorescence short-
stalked, ovoid-panicled, decompound with narrow
divisions 20 cm. long and short branches, the lower
with branchlets 3 cm. long. Perianth segments 2 mm. long. Fruit
broadly elliptical. 8-10 X 12 mm. Seed 3 X 4-5 "''"''• irregularly
3-lobed, smooth. — PL 8, 14.

South-central Mexico. Associated with the next and Dasylirion
lucidnui.

Specimens examined: Puebl.\. Tehuacan (Rose, Painter &
Rose, 10136, 1905, — the type of B. Purpusi; Rose & Rose, 11220,
1906; Purpus, 2^97, 1907). San Luis Tultitlanapa {Purpus, 5080,
1908). Oax.\ca. Tomellin Canon {Rose & Rose, ii42'/a and h,
1906). Almoloyas to Sta. Catarina ( ?Coii::atti, 1644, 1906).

B. GRACILIS Lemaire, 111. Hort. 8. misc. p. 61. 1861.

B. ccdipus Rose, Contr. U. S. Nat. Herb. 10: 88. pi. pj. 1906.—

AlacDougal, Publ. Carnegie Inst. 99. pi. ig.
'^Nolina histrix Hort.

Trunk enormously swollen below, variously and irregularly
branched. Leaves very glaucous, 4-7 mm. wide,
scarcely 50 cm. long, minutely but sharply serrulate-
scabrous on the paler margin. Inflorescence short-
stalked, ovoid- or oblong-panicled, decompound with
divisions scarcely 30 cm. long and weak branches half
as long, the lower often similarly branched. Perianth segments
scarcelv 2 mm. long. Fruit round-elliptical, 7-9 X 10 mm. Seed
2X3 mm., smooth. — PL 4, ii.

South-central Mexico. Associated with the preceding.
Specimens examined: Puebla. Tehuacan {Rose, Painter &

I9II-] TRELEASE— THE DESERT GROUP XOLIXE.E:. 431

Rose, loij/, 1905, — the type of B. cvdipiis; Trclcase, i, 1903; Pur-
pus, I2f,^a in part, 1905. and 2jo^, 1907). Cultivated. New
York Botanical Garden {Taylor, 2jys4, 1906).

Dasylirion.
Zuccarini, Allgem. Gartenzeit. 6: 258, 303. 1838. — Plant. Nov.
vel Alinus Cognit. 4: 221. pi. i (Abhandl. Akad. Aliinchen. CI. II.
3.^Denkschr. 16). 1840; — ^Plant. Nov. etc. 5: 19. (Abhandl.
Akad. Munchen. CI. II. 4. = Denkschr. 19). 1845. — Kunth, Enum.
Plant. 5: 38. 1850, — as Dasyliriuui. — Baker, Journ. Bot. 10: 296.
1872; Journ. Linn. Soc, Bot. 18: 237. 1880. — Rose, Contr. U. S.
Nat. Herb. 10: 89. 1906. — Though primarily based on Yucca
pitcainiiccfolia {Hcclitia gloiiicrata) and made to include with ques-
tion Yucca [Noliua] lougifoUa, it finally stood with its author for
the prickly-leaved sotols, of which D. scrratifolium and D. gramini-
foliuui were definitely included in his first publication on the genus
and mark its type.

Leaves 2-edged, usually somewhat concave and irregularly keeled, prickly-
margined and usually roughened with minute intervening denticles or
serratures (pp. 431-440). Eudasylirion.

_Fruit-small (3-5 mm. wide).

Fruit normally with moderately deep notch, narrowly elliptical to
obovate, the style not surpassing the wings. Perianth segments
about 2 mm. long. Leaves elongated, rather wide (usually 15-20
mm.).

Prickles prevailingly upcurved.

Dasylirion cedrosanum Trelease.

Dasylirion sp. Kirkwood, Pop. Sci. ^Monthly. 75: 438, 445. /.

Shortly caulescent. Trunk 1-1.5 m. high. Leaves 20 mm. wide,

upwards of i m. long, slightly brush-tipped, glaucous,

slightly rough-keeled, dull; prickles mostly 10-15 mm.

apart, 2-5 mm. long, yellow, becoming red upwards.

Inflorescence 5 m. high. Fruit very narrowly

elliptical, 4-5 X 7-9 nim., the style barely half as long as the narrow

deep notch. Seed 2 X 3-5 mm. PL 3, 12, if,.

Northeastern Mexico. Overlapping the range of Noliua
ccspitifcra.

432 TRELEASE— THE DESERT GROUP NOLIXE^. [April 21,

Specimens examined: Zacatecas. Cedros (Lloyd, 118, — the
type, and 82, 1908; Kirkzcood, q6, 1908). Coahuila. Rancho
La Luz (?Eiidlicli, 7, 1905). SaltjUo (?Grcgg, /8, 1846). Ango-
stura {'':lVislizcniis, ^oj, 1847).

D. LUCiDUM Rose, Contr. U. S. Nat. Herb. 10: 90. 1906.

Dasylirion sp. Schenck & Karsten, Vegetationsbilder. i. pi 46.

Shortly caulescent. Trunk 1-2 m. high or sometimes prostrately
elongated. Leaves 10-17 mm. wide, scarcely i m.
long, strongly brush-tipped, typically yellowish, A f^^

1^'

^

smooth and glossy: prickles mostly 10-15 "''i"'''- apart, i^l^^JSv/^

2-3 mm. long, from yellow passing through red to ^^^ ^ ^

almost chestnut, the margin often reddish. Inflorescence 2-3 m.
high. Fruit narrowly elliptical-obovate, 4-5 X 7-^ mm., the rather
slender style about half as long as the rather narrow deep notch.
Seed 2.5-3.5 i''"'!''''- — P^- -. 10, 12.

South-central ]\Iexico. \\'ith Bcaucaniea gracilis and stricta.

Specimens examined: Puebla. Tehuacan (Rose, Painter &
Rose, lOOOQ, 1905, — the type; Trclcasc, 1903, 1905; Purpns, 394/,
1909). Esperanza ( V- Purpns, 1907 ). San Luis Tultitlanapa ( JPiir-
piis, 50S2, 1908).

D. Palmeri Trelease.

Habit? Leaves 25 mm. or more wide, scarcely i m. long, some-
what brush-tipped, green or lightly glaucous, smooth,
^Vf^^ (T) '^^"^^' prickles mostly 15-25 mm. apart, 3-5 mm. long,
_^/^ _y^ yellow, becoming brown upwards, the intervening
■"" '' ' ^ margin rather smooth. Inflorescence moderately high.
Fruit narrowly elliptical- or triangular-obovate, 3-4 X 6 mm., the
stout style about equaling the rather open shallow notch. Seed 2X3
mm. — PL 12.

Northeastern ISIexico.

Specimens examined: Coahuila. San Lorenzo Canon' {Palmer,
6p6, 1905, — the type).

D. Parryanum Trelease.

Habit? Leaves becoming 10-15 mm. wide, scarcely 50 cm. long.

191 1-] TRELEASE— THE DESERT GROUP XOLIXE.E:. 433

brush-tipped, whitened, minutely roughened and
dull : prickles about 5 mm. apart, 2 mm. long, yellow,
becoming red upwards, the margin very rough be-
tween them. Inflorescence moderate, exceptionally
sub-simple. Perianth segments scarcely 2 mm. long.
Fruit elliptical or somewhat obovate, 4X6 mm., the style scarcely
equaling the narrow moderately deep notch. Seed?

East-central ^Mexico. In the region of D. graminifolinin and
NoHna hiiiiiilis and U'atso)ii.

Specimens examined : Sax Luis Potosi. Mcinity of San Luis
Potosi (Parry & Palmer, 8/6, 1878, — the type; Schaffncr, 242,
1878, — ^mixed with D. graminifoUum? ).
Prickles prevailingly recurved.

D. leiophyllum Engelmann in herb.

Dasylirioii sp. Trelease, Pop. Sci. Monthly. 70 : 220. /. 14.

Shortly caulescent. Leaves becoming 15-20 mm. wide, scarcely
I m. long, somewhat brush-tipped, green or at first somewhat
glaucous, smooth, rather glossy : prickles usually
10-15 mm. apart, 3-4 mm. long, yellow, usually be-
coming orange or red at least above the middle, the
margin sometimes smooth between them. Inflores-
cence rather high. Perianth segments scarcely 2 mm. long. Fruit
obovately subelliptical, 4-5 X 6-8 mm., the thick style about equaling
the moderately open and deep notch or exserted if the wings have
not fully developed. Seed 2X3 mm. — PI. 12.

Southern Texas, in the Rio Grande region, passing into New
^lexico and reaching or reappearing in central Chihuahua. — Ad-
joining or overlapping the range of D. IVhcelcri JVisli::c)u and
A^oUna crumpcns and affinis.

Specimens examined: Texas. Presidio (Haz'ard, i8?o. — the
type). Eagle Pass (':Havard. 1883). Sierra Blanca (Trdcasc.
1892. ^88, 1900; Midford, 2jj. 1895; Rose, Standlcy & Russell.
12222, 1910). Van Horn (Eggcrt, 1900). Xew^ Mexico. Cen-
tral {Midford, 424. 1895). Florida ^Mountains {Mulford, 10^/,
1895). Chihuahua. Sta. Eulalia ^Its. {Pringk, 14Q, 1885;
JJHlia))isou, 1885).

PROC. AMER. PHIL. SOC , L. 200 BE, PRINTED AUG. 7, I9II.

434 TRELEASE— THE DESERT GROUP XOLIXE^. [April 21,

Fruit with very shallow notch, broadly elliptical, the style rather surpass-
ing the wings. Prickles prevailingly upcurved.

D. TEXANUM Scheele, Linnsea. 23: 140. 1850. — Bray, Bull. Univ.

Tex. 82. pi. is; Bot. Gaz. 32 : 288. /.

Shortly caulescent or with buried trunk. Leaves 10-15 mm.
wide, scarcely i m. long, somewhat brush-tipped,
green, smooth or rough-keeled, glossy: prickles 5-10 Sy(/^X4!\\\
mm. apart, 2-3 mm. long, yellow, becoming brownish. U' '^■
Inflorescence 3-5 m. high. Fruit elliptical, 4-6 X 7-8 A
mm., the very short style equaling or surpassing the
open shallow notch. Seed ?^ — PI. 12, 75.

South-central Texas. In the range of Nolina tcxana and Liiid-
hckneriana.

Specimens examined : Texas. \' icinity of New Braunfels (Liiid-
hcimcr, 548, 1845, — apparently the type, 5^p, 1846, 1211-121^, 1849).
Blanco Canon (Rcz'crclwii, i6oj, 1885). Putnam (Trclcase, 1892).
Gillespie County (Jcrmy). Kerr County (Heller, 1929, 1894; Bray,
228, 1899). Hueco Tanks {Miilford, go, 1895). Sanderson {Wein-
berg, 1907; Thompson, 1911). Marathon {Lloyd, 1910). Com-
stock {Tlionipsou, 191 1). Ft. Davis {Blake).

D. texanum aberrans Trelease.

Differing from the type in its dull somewhat glaucous leaves, 15
mm. wide.

Northern Mexico.

Specimens examined : " States of Coahuila and Nuevo Leon "
{Palmer, ipf,, 1880, — the type).

Fruit rather small (5-6 mm. wide), subcordate, the style not surpassing
the wings.

D. simplex Trelease.

Acaulescent. Leaves 7-10 mm. wide, scarcely i m. long, rather

sparsely very long-fibrous at tip, green, smooth, glossy : prickles

10-15 or 20 mm. apart, 2-3 mm. long, rather straight,

'W<r^ vF] prevailingly upcurved, yellow, the upper half becom-

_/[___5/£^ ing brown or finally almost black, the margin nearly

smooth between them. Inflorescence (typically?)

small, the staminate with one to three small branches to each division

191 1.] TRELEASE— THE DESERT GROUP XOLIXE.E. 435

and the pistillate simple or its divisions with a short basal branch.
Fruit broadly obovate, 5-6 X / mm., the thick style about equaling
the open moderate notch. Seed (immature) 2X3 mm. — PI. 12.

North-central ^Mexico. In the region of Nolina durangensis.

Specimens examined : Dur.\ngo. Tepehuanes {Palmer, ^10,
1906, — the type). Santiago Papasquiaro (Palmer, ^22, 1896).

Fruit moderately large ^(usually 6-8 mm. wide), the style not surpassing
the wings. Prickles prevailingly upcurved. -V- ' ■

vLea^l not brush-tipped, glaucous.

D. GLAUCOPHYLLUM Hooker, Bot. Alag. iii. 14. pi. ^041. 1858. — [As
Dasylirium]. — Baker, Journ. Bot. 10: 298. 1872. — ?Gard.
Chron. iii. 40 : 247. /. lOi.
D. glaucum Carriere, Revue Hort. 44: 435. /. 1872. — Copied in
Garden. 3: 23. /., and Florist and Pomol. 1874: 17. /. — Card.
Chron. n. s. 13: 82, 205. /. j/. — ??Roezl, Belg. Hort. 33: 139.
?Z). serrafifoliiim Rept. 'Mo. Bot. Card. 14: 12. /.
Bonaparica glanca Hort.

Shortly caulescent. Trunk scarcely 5 m. high. Leaves as much
as 12 mm. wide, over i m. long, glaucous, nearly or
quite smooth, dull: prickles 5-10 mm. apart, 2 mm.
long, yellowish white or the tips becoming slightly
brownish. Inflorescence 4-6 m. high. Fruit sub-
elliptical, 6 X 9-10 mm., the thick style about half as
long as the closed deep notch. Seed 2.5 X 4 nim. — PL 12.

East-central Mexico. In the region of D. acrotriehe and Cali-
ba Jilts. — The type locality is Real del Monte.

Known to me only in cultivation. The fruit description is based
on material cultivated at La Alortola {Berger, j6o, 191 1).

Leaves more or less brush-tipped.

Leaves narrow (scarcely 10 mm.), strongly brush-tipped.

D. ACROTRiCHE Zuccarini, Abhandl. Akad. Munchen. CI. II. 3
(^Denkschr. 16) : 226, 228. pi i. f. iv. 1840.
Yucca acrotricha Schiede, Linnsea. 4: 230. 1829; 6: 52. —

Schultes, Syst. 7: 1716. 1830.
RouUnia gracilis Brongniart, Ann. Sc. Xat., Bot. ii. 14: 320.
1840.

436 TRELEASE— THE DESERT GROUP XOLIXE.^. [April 21,

Barbae Cilia gracilis Brongniart, /. c. — As synonym.

Yucca gracilis Otto, Allgem. Gartenzeit. 9: 123. 1841. — As

synonym.
Bonapartca gracilis Otto, /. c. — As synonym.
Dasylirion gracilc Znccarini, Abhandl. Akad. Miinchen. CI. II. 4

(=:Denkschr. 19): 22. 1845.
Dasyliriuui acrotrichuin Kunth, Enum. PI. 5 : 40. 1850. — Hooker,

Bot. Alag. iii. 14. pi. 30_^o. — Copied in Fl. des Serres. 14. pi.

1448. — Schlotthauber, Deutsch. Mag. f. Gart.-u. Blumen-

kunde. 1871 : 49, 64, 81, 96. 2 pi. — Koopmann, Gartenwelt. 3 :

375-6. /.
Dasyliriuui gracilc Planchon, Fl. des Serres. 7: 6, 10. /. 1851-2.
Littcca gracilis \^erschaffelt, Cat. 1864. — Hansgirg, Phyllobiol-

ogie. 422.
Dasylirion acrotriclnmi Baker, Journ. Bot. 10: 297. 1872. —
Kegel, Gartenflora. 30: 24. /.— Gard. Chron. iii. 19: 204. pi.
— Deutsch. Gartner-Zeit. 20 : 536. /.
?P. rohustum Hort. — {Y'er\\2.^s,^scrratifolium.)
Caulescent. Trunk at length i m. or more high. Leaves 6-10
or rarely 15 mm. wide, less than i m. long, green
and glossy or somewhat glaucous and dull, often
rough on the keels: prickles 5-10 or 15 mm. apart,
scarcely 2 mm. long, rather straight, pale yellowish,
with slightly brown tips. Inflorescence 3-5 m. or
more high. Perianth segments 2-3 mm. long. Fruit round-cordate,
6-7 X 8-9 mm., the thick style about equaling the shallow notch.
Seed 3 X 3-5 mm.— P/. //, 12.

East-central Mexico. Collected by Schiede and Deppe on the
Serro de la Ventana, on the flanks of Mt. Orizaba, by Karwinski at
Ixmiquilpan, and by Reppert at Real del ]Monte. Deppe's original
seed collection, in 1825 (Otto, Allgem. Gartenzeit, 16: 276. 1848)
was made between Real del ^lonte and Pachuca, and most of the
earlier plants of European gardens were raised from this at Berlin
(Bouche, Monatsschr. Verein Beford. Gartenbau. 1880: 481). —
Range of the preceding.

Specimens examined: Hidalgo. Dublan (Priiiglc, iiig6, 1902;

191 1-] TRELEASE— THE DESERT GROUP XOLIXE.^^. 437

Rose & Hay, j^o^, 1901). Metepec (Pringlc, loooi, 1904). Tula
{Pringle, 66^7, 1897; Rose, Painter & Rose, 8280, 1905). Ixrniqnil-
pan (Rose, Painter & Rose, 8p6p, 9029, 1905). Sierra cle Pachuca
{Rose, Painter & Rose, 5371, 1901 ; 8801, 1905 : Rose & Rose, 11484,
1906). OuERETARO. Cadereyta {Rose, Painter & Rose, 9714, igo$).
Sax Luis Potosi. San Luis Potosi {Parry & Palmer. 876, 1878).

Leaves wide (rarely under 15 mm.), only moderately brush
tipped.
Fruit elliptical or obovate.
Prickles small.

D. GR-\MixiFOLiuM Zuccarini, Allgem. Gartenzeit. 6 : 2-^<), 303. 1833 ;
Abhandl. Akad. Miinchen. CI. IL 3 ( = Denkschr. 16) : 225.
pi. I, f. I. 1840. — Kunth. Allgem. Gartenzeit. 9: 121. pi. i.
Yucca graminifolia Zuccarini, Cat. Hort. ]\Ionac. 1837.
Dasylirium graminifolium Kunth, Enum. PI. 5: 39. 1850.
Subcaulescent? Leaves 12 mm. wide, about i m. long, green,
smooth, glossy: prickles mostly 5-10 mm. apart, i
mm. long, yellowish white or with slightly darkened
tips. Inflorescence moderately high. Fruit broadly
elliptical, 6 X 8-9 mm., the thick style equaling the
rather open shallow notch. Seed ? — PI. 12.

East-central Mexico. The type is said by Otto to have been
raised from seed sent with that of D. acrotrichc by Deppe in 1827. —
As the earliest well-characterized and figured species, this may per-
haps be accepted as the type of the genus, though it follows D. ser-
ratifoliuin in position. — In the region of D. Parryanum, Calibanus
and A'olina huniilis and JVatsoni.

Specimens examined : Sax Luis Potosi. A'icinity of San Luis
Potosi (Parry & Palmer, 876, 1878; ?Schajfner, 242, 1878, — mixed
with D. Parryanum). Las Canoas (Pringle, 3746, 1891).

Leaves of D. hybrid uni of the Botanical Garden of Rome do not
differ from this except in being 15-20 mm. wide, nearly dull and
scarcely brush-tipped. It is said to be a hybrid between D. [Xoliiia]
longifolium and D. serratifolium, but in foliage shows no characters
of the former, and it is unlike the latter as I understand it.

Prickles moderate.

438 TRELEASE— THE DESERT GROUP XOLIXE.E. [April 21,

D. durangense Trelease.

Habit? Leaves 20 mm. wide, scarcely i m. long, lightly glau-
cous, nearly smooth, dull: prickles 5-10 mm. apart,
2-3 mm. long, yellow, with orange tips. Inflorescence
tall. Fruit broadly elliptical-cordate, 7-8 X 9 mm.,
the thick style scarcely half as long as the rather open
deep notch. Seed 2X3 mm. — PI. it, 12.

North-central Mexico. In the region of KoUna durangoisis.

Specimens examined : Durango. Durango (Fa/;/R"r, 557, 1896, —
the type).

D. SERRATiFOLiUM Zuccariui, Allgem. Gartcnzcit. 6: 258,303, — name
only. 1838; Abhandl. Akad. ^Iiinchen. CI. II. 3 (=Denkschr.
16 ) : 225, 228. pi. I. f. Hi. 1840. — Roezl, Belg. Hort. 33 :

139-
Yucca scrratifolia Schultes, Syst. 7. 1716. 1830.
Roulinia scrratifolia Brongniart, Ann. Sc. Nat., Dot. ii. 14: 319.

1840.
Dasyliriiiii! scrratifolium Kunth, Enum. PI. 5: 41. 1850.
Dasylirion laxiflorum Baker, Journ. Bot. 10: 299. 1872.
?Z). robiistuin Hort.

Subacaulescent. Leaves 15-20 or even 35 mm. wide, scarcely

I m. long, whitish, finely roughened on one or both

faces, dull : prickles 5-10 or even 20 mm. apart, 2-^

j/I T?7 — 7^ WiXn. long. Inflorescence ample. Fruit quadrately

v^7v_L./ — round-obovate, the style equaling the narrow rather

deep notch. Seed 3X4 nim.

Southeastern Mexico. Collected by Andrieux near Oaxaca, and
by Karwinsky at San Jose del Oro. — Region of NoHiia longifolia.

Specimens examined : Oaxaca. Las Sedas {Pringlc, ddgy, 1897) .
Nochistlan {Consatti & Goucalcs, 1899).

D. Wheelert Watson in Rothrock, Rept. Wheeler. 6: 378. 1878;
Proc. Amer. Acad. 14: 249. 1879. — Wooton, Bull. N. Mex.
Exper. Sta. 18: 92. pi. — Lloyd, Plant World. 10: 254. /. f;i. —
MacDougal, Publ. Carnegie Inst. 99: 74, pi. ^8. — De Wilde-
man. Icones Sel. Hort. Thenensis. 6: 91. pi. 22^. — Sketchy
habit figures, without name, are given by Schott in Emory,
Rept. Bound. Surv. i. pi. ^J, 42.

191 1.] TRELEASE— THE DESERT GROUP XOLIXE.E. 439

Shortly caulescent. Trunk scarcely i m. high. Leaves 15-20
or 25 mm. wide, scarcely i m. long, glaucous, nearly
smooth, dull: prickles 5-10 mm. apart, 2-3 mm. long,
yellow, becoming brown upwards. Inflorescence 3-5
m. high. Fruit round-obovate, 6-7 X 7-9 mm., the
style normally about equaling the open moderately deep notch. Seed
(immature) 3 mm. long. — PL /, 8, 11, 12.

Southeastern Arizona and adjoining ^Mexico, Xew Mexico and
Texas. Region of Koliiia microcarpa and caiidata.

Specimens examined: Arizona. Ash Creek, etc. (Rothrock, ^2p,
6jj, — the types). Rio Grande to Gila Rivers (Emory, 1846). Sun-
flower Valley (Girard, 1873). Dragoon Summit (Vasey, 1881).
Sta. Catalina ^Mountains {LcDimon, 1881 ; Pringle, 1881 ; Tourney,
1894). Without locality {Pringle, 1884). Sta. Rita ^Mountains
{Brandegee, 1891 ) . Ft. Huachuca ( Wilcox, 208, 264, 1894) . Chiri-
cahua Mountains (Touiney, 1894). San Carlos {Straiih, 1895).
Xogales {CoviUc, 162^, 1903; TJiompson, 1911). White Tail (Pils-
bry, 1906). Benson (Rose, Staiidley & Russell, 12^26, 1910). Xew
Mexico. Silver City (Greene, 1880; Metcalfe, dj/, 1903). Burro
Mountains (Rusby, 41J, 1881, — leaves). Pinal ^Mountains (Tourney,
449, 1892). Las Cruces (IVooton, J2, 1897). Mangos (Metcalfe,
1897). Kingston (Metcalfe, 1014, 1904). Alamogordo (Rehn &
Viereck, 1902). Organ Mountains (Standlcy, 1906). Texas. El
Paso (Evans, 1891). Tortugas Mountains (Rose, Standley & Rus-
sell, I22J4, 1910). Boundary Line (Parry ct al.). Chihuahua.
Lake Sta. Maria (Nelson, 6^93, 1899).

Fruit triangular-obcordate : prickles moderate.

D. Wheeleri Wislizeni Trelease.

Shortly caulescent. Leaves 15-20 mm. wide, scarcely i m. long,
green or slightly glaucous, typically smooth and rather
glossy : prickles 5-10 mm. apart, 2-3 mm. long, red-
brown or with yellow base, the intervening denticles
often reddish. Inflorescence ample. Fruit triangular- "^ —
obcordate, 6-7 X 8-9 mm., the thick style about equaling the open
moderately deep notch. Seed (immature) 3 mm. long. — PI. 12.

440

TRELEASE— THE DESERT GROUP NOLIXE.^. [April 21,

North-central Mexico and adjacent Texas, — apparently grading
into/). Jllwiicri. Adjoining or overlapping the area of D. WJiccleri
and Nolina crump ens.

Specimens examined: Chihuahua. Paso del Xorte [Juarez]
{Wislisenns^ 218, 1846, — the type; ?Stcar)is, 1910, — with smaller,
slightly roughened dull leaves). Without locality (TJiiirbcr, 1852).
Texas. El Paso {Dez^'cy, 1891 ; Wagner, p8j, 1892). Franklin
Mountains (Rose, Stajidlcy & Russell, 12280, 1910).

Fruit large (8-9 mm. wide), the style surpassing the wings.

D. Berlandieri Watson, Proc. Amer. Acad. 14: 249. 1879.

Habit ? Leaves ? Inflorescence apparently ample. Bractlets
rather long, lanceolate, finely toothed. Perianth seg-
ments 2-4 mm. long. Fruit round-elliptical, 7-9 X
7-10 mm., the style rather exceeding the very open
moderately deep notch. Seed ? — PL 12.

Northeastern ?^Iexico.

Specimens examined: Nue\T) Leon. La Silla, Monterey {Bcr-
landier, 3218, June, 1843, — the type).
Leaves 4-sidcd, unarmed. Quadra ngul.'KT.t:.

D. LOXGissiMUM Lemaire, 111. Hort. 3. misc. p. 91. 1856.

D. quadrangulatuui \\"atson, Proc. Amer. Acad. 14: 250. 1879. —
Gartenflora. 36 : 280. /. 75. — Bull. Soc. Tosc. Ort. 9 : 236. /. ;
35: 331. pi. 6. — Die Natur. 34: 340. /. — Hooker, Bot. Mag.
iii. 56. pi 'JI4C).
D. jujicifoliuiii Rehnelt, Gartenwclt. 11 : //. f. 1906.
Caulescent. Trunk 1-2 m. high. Leaves narrowly linear, 3-8
mm. wide, at length 2 m. long, not brush-tipped, green, dull, rhombic
-f-.^ or square in section, smooth, the edges minutely gran-
ular-roughened or further with very low elevations
\</^ 10-30 mm. apart representing the prickles of other
species. Inflorescence 2-6 m. high. Perianth seg-
ments 3-4 mm. long. Fruit broadly obovate or elliptical, 5-8 X 7~io
mm., the st\le surpassing the open very shallow notch. Seed 3 X 3-4
mm. — PL g, 12.

Eastern Mexico. Of wide range, overlapping the regions of
Nolina Nelsoni, Caliban us and D. acrotrichc.

I9II.] TRELEASE— THE DESERT GROUP XOLIXE.E. 441

Specimens examined : Tamaulipas. Sierra Xolas, between San
Luis Potosi and Tampico (Palmer, 1878-9, — the type of D. qiiad-
raiigiilafiDii ) . Aliquihuana ( Xc/soii, 4480, 1898) . Sax Luis Potosi.
^linas de San Rafael {Piirpiis, joOQ, 1910, — a form with small fruit.
4X4 mm., with style and wings abbreviated and equal). Hidalgo.
Sierra de la Alesa (Rose, Painter & Rose, <)ogj, 1905, — called
'■ junquillo ").

TEXT REFEREXCES.

^ Bouche, Sitzungsber. Ges. X'aturf. Freunde. Berlin. 1875; 118. — ]Mon-
atsschr. Verein Beford. Gartenbau. 23 : 482. 1880.

" Bray, Bull. Torr. Bot. Club. 30 : 627. /. 6. 1903. — Bull. Univ. Texas. 60 :
22-24. 1905-

^ Bruno. Boll. Soc. Xatural. Xapoli. 19 : 159. 1906.

* Christy. Xew Commercial Plants and Drugs. 6: 42. 1882.

^Engler & Prantl. Xatiirl. Pflanzenfam. 2 Teil. 5 Abteil. p. 71. /. 5/.
1887.

'" Hansgirg, Sitzungsber. Bohm. Gesellsch. igoi""*: 31. — Phyllobiologie. 421.
1903.

^ Havard, Bull. Torr. Bot. Club. 23: 43. 1896. — Amer. Journ. Pharm. 68:
267. 1896.

* Hooker, Curtis's Bot. Mag. iii. 14. />/. 5041. 1858.
' Kirkwood, Pop. Sci. Monthly. 75 : 446. 1909.
"Klebs, Unters. Bot. Inst. Tubingen, i: 568. /. 13. 1885.

"Lemaire, 111. Hort. 8. misc. p. 61. 1861. — See also Gard. & For. 9: 94
1896.

^- Lloyd, Plant World. 10: 254-5. /• 5^- IQO"-

" McClendon, Amer. Xat. 42 : 308. ft. 190S.

"Newberry. Bull. Torr. Bot. Club. 10: 123-4 1883.

''Orcutt, Bull. Torr. Bot. Club. 10: 106-7. 1883.

'^Pirotta, Ann. R. 1st. Bot. Roma. 3: 170. pi. 20, 21. 1888.

^'Preda, Bull. Soc. Bot. Ital. 1896: 135-141.

"Reverchon. Bot. Gaz. 11: 213. 216. 1886.

" Rose, Contr. U. S. Xat. Herb. 5 : 224, 240. pi. j6, $7. 1889.

^"Solms Laubach, Bot. Zeit. 36: 69. pi. 4. 1878.

^ Trelease, Pop. Sci. Monthly. 70: 219. 1907.

■' Went & Blaauw, Proc. Sect. Sci. K. Akad. Amsterdam. 8 : 684 ; Rec.
Trav. Bot. Neerland. 2 : 223. pi. 5. 1906.

""Wooton, Bull. X. Mex. Agr. Exp. Sta. 18: 92. 1896.

"*Zuccarini, Allgem. Gartenzeit. 6: 303. 1838; Abhandl. Akad. ]Munchen.
CI. II. 3 : 224, 228. 1840.

In addition to those noted in the above papers, histological studies are to
be found in De Bary, Vergl. Anat. 636-640. — Cedervall, Anat.-Fys. Unters. —
Cerulli-Irelli, Ann. R. 1st. Bot. Roma. 5 : 414. — Falkenberg, Vergleich. Unters.

PROC. .\MER. PHIL. SOC, I,. 200 CC, PRINTED .\UG. 7, IQIt.

442 TRELEASE-THE DESERT GROUP XOLIXE/E. [April 21,

Monocot.— Giovannozzi, Nnov. Giorn. Bot. Ital. n.s. 18; 9, 53. /. 14.— Gre-
villius, Bot. Notiser. 1887: 140.— Haberlandt, Ber. Deutsch. Bot. Ges. 4: 223.—
Hausmann, Beih. Bot. Centralbl. 23. Abt. 2: 43-80. #.— Kny, Bot. Wandtafeln.
Abt. 5.— Mobius, Ber. Deutsch. Bot. Ges. 5: 22.— Morot, Ann. Sci. Nat., Bot.
vi. 20 : 272.— Schoute, Flora. 92 : 42, 46. />/. 4- f- 5, /o.— Schwendener, Abhandl.
Akad. Berlin. 1882.

EXPLANATION OF ILLUSTRATIONS.

The distribution map indicates the occurrence of specimens actually
examined. Half-tone plates are from mipublished photographs by the author
unless otherwise credited. Text-cuts are uniformly reduced from enlarged
camera lucida drawings to natural size except that leaf sections are X 2, the
finer arming of leaf margins X 20, and the style and wing tips of Dasylirion
X 6; and a few exceptional details with other enlargement are introduced.

Plates 1-4. Habit of growth: i, Trunkless (Nolina microcarpa, Arizona,
MacDougal) ; 2, with elongated finally erect caudex (Dasylirion lucidum,
Tehuacan) ; 3, arborescent (Nolina longijolia, cultivated in the Palermo
botanical garden) ; 4 arboreous {Bcaucarnea gracilis, Tehuacan). All greatly
reduced.

Plate 5. Habit of inflorescence: — A, Simply panicled (Nolina gcorgiana
Georgia, Harper) ; B, Compoundly panicled (A''. Parryi, California, Jepson) ;
C, Compoundly spicate (Dasylirion ccdrosanum, Mexico, Lloyd). — All greatly
reduced.

Plates 6-7. Inflorescence details : — 6 A, Nolina caudata (type) ; 6 B,
Calibanus Hookcrii (Purpus, 4775) ; 7 A, Beaucarnca giiatcmalensis (Keller-
man, 6069); 7 B, Dasylirion Wheelcri S and $ (Wooton, 72).— All natural
size.

Pl.'\te 8. Flowers.— A, Nolina longijolia (Radlkofer) ; B, Calibanus
Hookerii (Rose, 8954); C, Bcaucarnea stricta (Purpus, 2397); D, Dasylirion
Wheelcri (Toumey). — All X 10.

Plate 9. Septal nectar slits as shown on the matured fruit. A, Dasylirion
longissimum (Palmer); B, Calibanus Hookcrii (Purpus, 1200). — Both X 25.

Plate 10. Seeds. A, three seeds of Nolina durangensis, — the middle one
sectioned to show coat, endosperm and embryo; a seed of Beaucarnca plia-
bilis; and two seeds of Dasylirion lucidum.— AW X 3. B. endosperm of
Dasylirion lucidum, with " reserve-cellulose " walls. X 200. C, cross section
of seed of Nolina durangensis showing embryo cavity with much extruded
protoplasm and oil— in chlor-iodide of zinc. X 20. D, endosperm of Nolina
durangensis swollen in chlor-iodide of zinc, with extruded oil. X 200.

Plate ii. Fruit characters. A, four fruits and a seed of Nolina
georgiana; six fruits and two seeds of Dasylirion Wheelcri; six fruits and
two seeds of Beaucarnca gracilis; and four fruits and a seed of Calibanus
Hookcrii.— AW natural size. B, i, Dasylirion acrotriche (3 and 4-winged) ; 2,
D. acrotriche (4- and 5-winged) ; 3, D. durangcnsc (2- and 5-winged) ; 4,
D. Wheelcri (4- and 5-winged) ; 5, Calibanus Hookcrii (4-carpellary). —
All X 2.

191 1.] TRELEASE— THE DESERT GROUP XOLIXEyE. 443

Plate 12. Fruit characters. A, Xolina: Graminifolije (four fruits of
N. Lindheimeriana) , — Microcarpae (branchlet of .V. microcarpa) , — Erumpentes
(branchlet of A', texana), — and Arborescentes (four fruits of N. Parryi). —
All natural size. B, Dasylirion: i, D. ccdrosanum (type), — 2, D. lucidum
(Trelease, 26),— 3, 4rU. ieiophyllum (3, Van Horn, Eggert, 4, type),— 5,
D. Palmcri (type), — 6, D. texanmn (Lindheimer, 1213), — 7, D. simplex (type),
— 8, D. Wheeleri IVisUzcni (type), — 9, 10, D. Wheelcri (9, Girard, 10,
Wooton, 72), — II, D. durangense (type), — 12, D. graminifolium (Pringle,
3746), 13, D. glaucophyllum (Berger), 14, D. acrotriche (Haage & Schmidt),
— IS, D. Berlaiidieri (type), — 16, D. loiigissimum (type), — All natural size;
four numbers in a row, from left to right.

Plate 13. Germination of Nolina longifoUa. — A, normal seedlings, one
with slightly shouldered haustorium. B, various straightening of the cotyle-
don from normal arch to erect form. — All X 3.

Plate 14. Germination. A, Bcaucarnca stricta. — the haustorium in
place, though broken off (Rose). B, Calibanus Hookerii (Rose). The haus-
torium deeply dorsal on the cotyledonary sheath. — Both X 3.

Plate 15. A, Dasylirion ccdrosaiiuiii, seedling with deeply dorsal haus-
torium, X 2; B, D. texanum, mature leaf tips showing dorsal exfoliation of
fibers, natural size.

Plate 16. Nolina Hartzvcgiana. (Hartweg, 406, in Herb. Delessert).
C. de Candolle. — Reduced.

Plate 17. Nolina rigida. Anatis rigida. (Plate XVHI of the Sese
and Mogino drawings in Herb. DC., by Node-veran.) C. de Candolle.
— Natural size.

ISOSTASY AND MOUNTAIN RANGES.

By harry fielding REID.

(Read April 21, 19 n.)

The cause of the elevation of mountains has ahvays been a most
fascinating subject of study, and we find the earher geologists giv-
ing much attention to it. In the first half of the nineteenth century
the prevailing idea was that mountain ranges were due to the upward
pressure of liquid lava and that their elevation was closely related
to the volcanic forces. As late as the middle of the century Elie de
Beaumont upheld this idea with all the prestige of his great authority.

But a more detailed study of the structure of the rocks wdiich
make up the mountains led to dift'erent conceptions. It was found
that the whole mass had been subjected to tremendous compressional
forces in a line at right angles to the mountain range. This was
shown by the immense folding of the rocks, the existence of thrust-
faults and of cleavage and the evident flattening out of fossils; so
that the existence of these tangential forces was thoroughly proven.
This led then to the idea that mountains owe their origin not to
vertical forces, but to the great tangential forces which folded the
rock and squeezed it upwards. Professors Heim and Suess in
Europe, and Dana, Hall and Le Conte in America, were all very
active in developing this point of view, though Dana realized that
vertical forces also played some part in the elevation of mountains ;
but the dominant influence of the tangential forces was recognized
in the udLine orogenic, or mountain-making {orcts,\\\-\\c\-\\\2iS reserved
entirely for them. Without doubt, confidence in the efficiency of
tangential forces was greatly strengthened by the fact that these
forces could be satisfactorily accounted for by the cooling of the
earth ; for the cooling is greatest at a short distance below the sur-
face and the exterior layers are subjected to tangential crushing to
accommodate themselves to the shrinking interior.

444

19"] REID— ISOSTASY AXD MOUNTAIN RANGES. 445

There are great areas of the earth, such as the high plateau
regions in the west of the United States, where the rock has been
elevated many thousands of feet but without suffering any com-
pression whatever, which makes it quite evident that there are ver-
tical forces which produce many movements in the earth's crust.
Mr. Gilbert has given to these forces the name of cpcirogenic, or
continent-making forces, to distinguish them from orogenic forces;
but we must not forget that epeirogenic forces are apparently alone
active in the elevation of certain mountain ranges. The Sierra
Nevada, for instance, although its strata are much folded, owes
its present elevation to the vertical forces which seem still to be
tilting the great block. Alt. St. Elias also seems to have been tilted
up by vertical forces without any folding of its strata.

The American geologists showed that a mountain range does
not rise haphazard in any part of the earth, but that it appears where
there was earlier a great geosynclinal, which had gradually sub-
sided and accumulated sediments to an extraordinary thickness, all
of them being laid down in comparatively shallow waters ; and it
was only after this preparatory step that the foldings and elevation
of the mountain range took place.

But there is one important factor to which geologists have not
given proper attention, that is, the revelations of the plumb-line.
About the middle of the nineteenth century Archdeacon Pratt
pointed out that in the south of India the plumb-line was deflected
toward the Indian Ocean, and in the north of India, although it
was deflected somewhat toward the Himalaya mountains, still the
gravitational attraction of these mountains was considerablv less
than it should have been, if the density of the material in and under
them had been the same as in other parts of the earth's crust; and
he, therefore, suggested that the oceans were deep because the
material under them was heavy, and the mountains were high
because the material which composed them was light, and that in
general the amount of material under any two equal segments of
the earth was the same. But these facts did not make a great im-
pression upon geologists and did not prevent the further advocacy
of compression and the consequent accumulation of material as the
cause of mountain elevation.

PROC. AMER. PHIL. SOC, L. 200 DD, PRINTED AUGUST 7, I9II.

446 REID— ISOSTASY AND MOUXTAIX RANGES. [April 21,

In 1880 yir. Faye showed that the so-called "anomalies" of
gravity would practically disappear if, in reducing observations on
land to sea-level, no account were taken of the land mass above sea-
level ; and if, in reducing observations made on islands in mid ocean,
the excess of attraction of the island mass- over an equal amount
of sea-water were subtracted. This is equivalent to assuming that
the continental areas stand up on account of their low densities, but
that the small islands are supported by the rigidity of the crust. ^

In 1889 Major Button read a very remarkable paper before the
Philosophical Society of Washington,- in which he pointed out that
the mountain regions were probably continuing to rise as a result
of the lightening of their weight by erosional transportation and that
regions of deposition near the coasts were probably sinking on
account of the added material which they were receiving, and that
the forces thus brought into play would set up slow currents from
the regions under the sea towards the region under the mountains ;
and he held that the earth was not strong enough to sustain the
weight of great mountain ranges but that these owed their elevation
to the fact, as already suggested by Archdeacon Pratt, that they
were lighter than the material under the lowlands, or under the
oceans; and that there was, therefore a certain equality of weight
in the various segments of the earth. He gave to this theory the
name of isostasy, which has served to give it definiteness ever since.
It is to be noticed that Major Button considered the elevation of
mountains to be due to vertical, and not to tangential forces.

The theory of isostasy has been much discussed by geologists
since ]\Iajor Button's paper; many papers have been written on the
subject, and the available geological evidence has been invoked in
support of, or against, the idea ; but it was not until very recently that
the real evidence, which lies in the variations of the force of gravity
and the deviation of the vertical, has led to definite conclusions.

Mr. Putnam and Mr. Gilbert"'' discussed a series of gravity ob-

^"Sur la reduction des observations du pendule an niveau de la mer,"
C. R. de I'Acad. dcs Sciences, 1880, Vol. 90, pp. 1443-1447-

-"Some of the Greater Problems of Physical Geology," Bull. Pliilos.
Soc. of Washington, 1889, Volume XL, pp. 51-64.

^"Results of a Trans-Continental Series of Gravity Measures," Bull.
Philos. Soc. of IVashini^ion, 1895, Volume XIII., pp. 31-/6.

191 1.] REID— ISOSTASY AND MOUNTAIN RANGES. 447

servations made across the United States, which led them to the
conclusion that isostasy was true only in so far as the very largest
features of the earth's crust, such as the continents and ocean basins,
were concerned, but that mountain ranges were at least in part sup-
ported by the rigidity of the crust.

When Dr. Nanscn drifted across the North Polar basin in the
Fraiii he provided pendulums to determine the force of gravity
when the ship was frozen in ice ; and the discussion of his observa-
tions showed that gravity was normal over that basin, or, at least,
where his observations were made.*

Professor Helmert,^ in Germany, has done much in the discus-
sion of gravity measures and Dr. Plecker has made some notable
voyages and has determined the forces of gravity at sea, over the
Atlantic, Indian and Pacific oceans, and over the Black Sea, the
results showing that on the whole the force of gravity is normal
over these bodies ; only in special and limited areas, in the neighbor-
hood of very steep slopes, was any marked anomaly found."

But the most important work which has been done along this
line is the work of Dr. John F. Hayford,' who, while connected with
the United States Coast and Geodetic Survey, discussed in a thor-
ough and able manner the deflections of the vertical at a large num-
ber of stations in diiTerent parts of the United States, and his results
show definitely that over this region isostatic eciuilibrium actually
exists. He has concluded that this is true even for areas as small
as a square degree, that is, seventy miles on the side. He believed

* " The Norwegian North Polar Expedition of 1893-96," Volume II.,
Part VIII., Results of the PenduUun Observations, bj^ E. O. Schiotz.

° " Hohere Geodesie," Leipzig, i&So.

'" Bestimmung der Schwerkraft auf dem Atlantischen Ozean," I'croff.
des Konig. Preuss. Geodet. Instit., Neue Folge, No. 11. "Bestimmung der
Schwerkraft auf dem Indischen und Groszen Ozean," Veroff. des Zentral
Bureaus der Interuat. Erdmessiing, Neue Folge, No. 18. " Bestimmung der
Schwerkraft auf dem Schwarzen Meere," same. No. 20.

'"The Geodetic Evidence of Isostasy, etc.," Proc. JVashingtoii Acad
Sci, 1906, Vol. VIIL, pp. 25-40. "The Earth a Failing Structure," Bull.
Philos. Soc., Washington, 1907, Vol. XV., pp. 57-74. " The Figure of the
Earth and Isostasy," United States Coast and Geodetic Survey, 1909. " Sup-
plementary Investigation in 1909 on the Figure of the Earth and Isostasy,"
same, 1910. " The Relation of Lsostasy to Geodesy, Geophysics and Geology,"
Science, February 10, 191 1,

448 REID— ISOSTASY AND MOUNTAIN RANGES. [Apni 21,

that the earth is not strong enongh to sustain an added thickness of
more than alxtut two hun(h-ed and fifty feet of rock over an area as
large as a square degree without slowly yielding. The stations
where the ohservations were made are scattered over various parts
of this country, on the eastern coast, in the Appalachian mountain
range, in the region of the Great Lakes, near the Gulf of Mexico,
in the great plains of the Mississippi basin, on the great elevations
of the Rocky Mountains, the plateaux of Utah, the Sierra Nevada
mountains and the Pacific coast, regions exhibiting a great variety
of topographic forms and differing greatly as to geologic activity.
Whatever movements may be going on in the Rocky mountains,
and in the region between them and the Atlantic ocean, are certainly
very small ; whereas to the west, and particularly in the state of
California, the movements seem to be very active. The eastern
edsfe of the Sierra Nevada received additional elevation at the time
of the Owens Valley earth(iuake in 1872, and the comparatively
frequent earth(|uakes in the Sierras and the Coast ranges make it
quite possible that these mountains are now being elevated as actively
as at any time in their history. In view of the great variety of the
country in which the stations were located, both as to topography
and geologic activity, in view of the great amount of material being
continually eroded from one region and deposited in another, thus
tending to overthrow the isostatic equilibrium, and in view of obser-
vations in other parts of the world, we are driven, with Dr. Hay-
ford, to the conclusion that isostasy is not an accidental condition
existing at the present time within this country, but is due to the
fact that the earth yields plastically to the long continued action of
even small forces. We feel justified, therefore, in believing that
isostatic equilibrium exists in other parts of the world and existed
in other geologic ages, and in saying that the whole earth is, and
always has been in isostatic equililjrium.

This conclusion carries with it many important consequences and
has a very direct bearing on the theories of the origin of mountain
ranges ; for it tells us that every segment of the earth, having an
equal area of surface and with its a])ex at the center, contains the
same amount of material, which it is impossible either to increase

191 1.] REID— ISOSTASY AXD ^lOUXTAIX RANGES. 449

or decrease. If by erosional transportation a large quantity of
material is removed from a high land and deposited in the oceans,
then the increase of weight under the ocean and the decrease under
the mountains will, as ]\Iajor Dutton explained, set up a subter-
ranean counter flow, which will restore the equality of material in
the segments. If by the exercise of tangential forces a portion of
the earth's crust is compressed and folded and the quantity of
material in the segment thus increased, the added weight will cause
a slow sinking of the region and material will flow out from below
and reduce the mass of the segment to its proper value. Indeed,
the folding up of the rock by tangential pressure would not elevate
a mountain range, but would cause the folded region to sink ; not,
however, necessarily below its former level.

When we consider the origin of the mountain ranges the theory
of isostasy requires that all hypotheses, which call for more than
the normal amount of material in any segment, be excluded. The
folding of rock under tangential forces, and the increase of material
by subterranean flow are necessarily debarred. Dana noticed that
the great mountain ranges of the world were opposite the great
oceans and, in some cases, were opposite the great depths of the
oceans. The inference was natural that material was taken from
the ocean bed, increasing its depth and added to the land increasing
its height ; but the theory of isostasy forbids this inference. He also
suggested that the segments of the earth forming the oceans were
sinking more rapidly, as the earth cooled, than the segments forming
the continents and also that they were stronger ; so that they com-
pressed the continents, folding the rock and making mountain ranges
around their borders. Besides other objections to this idea, the
theory of isostasy excludes it on account of the increased material
required in the land segment. Professor Charles Davison- has sug-
gested^ that the oceans owe their existence to the stretching and
consequent thinning of the strata below them, but the theory of
isostasy does not permit the withdrawal of material from the ocean

* " On the Distribution of Strain in the Earth's Crust resulting from
Secular Cooling, with special reference to the Growth of Continents and
the Formation of Mountain Chains," Phil. Trans. R. S., 1887, Vol. 178(A),
pp. 231-242.

450 REID— ISOSTASY AND MOUNTAIN RANGES. [April 21.

bottoms. Sir George Darwin'' has suggested that the continental
areas of the earth may be due to elevations caused by the differen-
tial retarding effect of lunar tidal action. But the theory of isostasy
tells us that they could not have maintained themselves unless they
were especially light ; and in this case they would have existed inde-
pendently of the tidal forces. Although these elevations, or
" wrinkles," as Sir George Darwin calls them, might have been dis-
torted by the dift'erent tidal effects in different latitudes, their orig-
inal meridional direction still requires explanation.

The foldings and contortions of the rock have been so intimately
associated, in the minds of geologists, with mountain ranges, that
a low-lying region of folded rock has been looked upon as the
remains of a mountain range removed by erosion ; but as mountains
are not due to rock folding, this inference may be entirely wrong.

Only a few of the consequences of the theory of isostasy have
been mentioned ; but the principle is of such fundamental importance
that it will surely exercise a strong influence over our future theories,
and will be applicable in directions not now suspected. Unfortu-
nately, it does not tell us definitely what is the cause of the elevation
of mountains and plateaux; but it limits our inquiries by excluding
all theories which assume the addition of matter to a segment. It
tells us, quite definitely, that the elevation of mountains, or the
depression of the oceans, must be due to vertical forces brought
about by a decrease, or increase, in the density of the material under
these regions. According to it, the mountains are high because their
material is light ; and as geological history tells us that the mountains
have not always existed, we must conclude that they were elevated
by an expansion of the material in and under them. And the great
deeps of the oceans are deep because the material under them is
dense and they have become deep by an increase in the density of
this material. Since all mountain areas are being lowered by active
erosion and many of the great ocean deeps are being filled by depo-
sitions, the great heights of the former must be due to the fact that
they are still in the process of elevation or that they have only

""Problems connected with tlie Tides of a Viscons Spheroid," /'/;/'/.
Trans. R. S., 1879, Vol. 170, p. 589.

191 1-] REID— ISOSTASY AND MOUNTAIN RANGES. 451

recently been raised; and the great depths of the latter to the fact
that they are in the act of sinking, or have only recently sunk. As
the centres of the great majority of strong earthquakes are along
the boundaries of high mountain ranges, or of great ocean deeps,
it seems most probable that the forces which have produced these
very interesting features of the earth's surface are still in active
operation.

A FOSSIL SPECIMEN OF THE ALLIGATOR SNAPPER
(MACROCHELYS TEMMINCKII) FROM TEXAS.

(Plates XVIII AND XIX.)
By OLIVER P. HAY.
(Received May 23, 191 1.)

The writer has received for examination from Professor Mark
Francis, of the Texas Agricultural Experiment Station, at College
Station, Tex., a nearly complete skull of the great fresh-vvatcr tor-
toise known as the alligator snapper. This fine specimen was dis-
covered last summer or autumn during some dredging operations in
the Brazos River, hetwecn College Station and Navasota. After
passing through various hands it came into the possession of Pro-
fessor Francis, who, on application, kindly transmitted it to me.
With the skull came also a part of a carapace, which doubtless be-
longed to the same animal. The skull was found in a mass of
gravel, and had undoubtedly been washed out of the river bank
not far away. This proximity of the place of burial is evident from
the little damage done to the skull, and is made more probable from
the presence of a part of the shell.

The cavities of the skull, when it came into Professor Francis'
hands, were full of gravel, wedged in very tightly. Some of this
gravel was sent with the skull. It was strongly colored with iron
oxide ; and this oxide served to cement the bits of gravel together
and to the bone. The bone is also colored with the oxide, and it
is so thoroughly mineralized that, on being struck, it rings like a
piece of porcelain.

It would l)c interesting to know exactly the geological age of
this specimen ; but it appears now impossible to determine this.
Professor Alexander Dcussen, of the LTniversity of Texas, has been
engaged in studying the Quaternary and Recent deposits of some
of the rivers of Texas ; and a part of his results is soon to be pub-
lished by the ITnitcd States Geological Survey. He has kindly in-

452

191 1-] THE ALLIGATOR SNAPPER FROM TEXAS. 453

formed the present writer that there occur along the Brazos River
three principal terraces. The oldest and highest of these, the
Hidalgo Falls terrace, lies at a height of lOO or more feet above the
present water line of the river. In the materials of this terrace
have been found remains of Maiiiiiiiit, Elcphas, Mcgalonyx, Eqiius,
etc. About 75 feet below this terrace is found another, the Port
Hudson, whose thickness is from 20 to 30 feet. The upper terrace
is regarded as older Pleistocene; the Port Hudson, as newer
Pleistocene. At a level some 15 to 20 feet below that of the Port
Hudson, is a terrace which Professor Deussen considers as of
early Recent time. It constitutes the real " bottom lands " of the
Brazos and is subject to overflow.

It is very probable that the remains described here were derived
from the lowest and youngest terrace and that the individual lived
at some time about the beginning of the Recent epoch. The species
probably lives today in the Brazos River.

The skull (plates X\TII and XIX) lacks the lower jaw, a part
of the temporal roof of the left side, most of the occipital condyle,
and the hinder part of the supraoccipital process. A close exami-
nation reveals no characters by which it can be distinguished spe-
cifically from the alligator snapper. The profile (PI. XIX, Fig. 2)
is much less concave than in most specimens of the species collected
in the rivers of the Southern States ; but there is in the United States
National Museum a skull of considerable size, no. 3769, from
IMississippi, which presents no greater concavity than does the
Brazos River specimen. There are two other skulls, the one con-
siderably larger than the skull from Mississippi, the other con-
siderably smaller, both of which are much more concave than the
specimen from Mississippi. Hence, the amount of concavity seems
not to depend on youth or old age.

The skull of the fossil is, relative to the length, slightly both
broader and higher than are two skulls with which it is compared,
as is here shown :

Snout to
Specimen. condyle. Width. Height.

Brazos River skull i 1.19 -84

No. 3769 U. S. N. M., from Mississippi I 1.14 78

No. 3444 U. S. N. M., from Red R., Ark i 1.08 .74

454 HAY— A FOSSIL SPECIMEN OF IMay 23,

It will be observed tbat the last two skulls differ from eaeh other
about as much as the second differs from the fossil.

The same three skulls furnish the following measurements.

l'ra7os R.
Meisurements. skull. No. 3769. No. 3444.

Snout to occipital condyle i83± i/O 177

Snout to hinder end of supraoccipital process.. 262± 236 226

Least width pterygoid region ;ii 29 29.5

Outside to outside of quadrates 187 166 163

Distance between hinder ends of cutting edges

of upper jaws 142 128 126

Width in front of ear cavity 218 195 191

Width of temporal arch where narrowest 77 71 68

Orbit to excavation of postorliital arch 87 82 80

Horizontal diameter of orbit 32 30 32

Distance between fronts of orbits 55 50 53

Fig. I of Plate XIX represents the fragment of the carapace that
accompanied the skull. This is reduced to five twelfths the natural
size. It consists of a part each of the third and fourth costal plates,
and of a part each of the sixth and seventh peripherals. On these
parts are present areas rei)rcsenting the outer and hinder angle of
the third costal scute, a little of the third and the whole of the
fourth supramarginal scutes, the wdiole of the eighth marginal scute

Fk;. I. Sectiiin of rim of carapace bclwecn .-^ixth and seventh peripherals.

and a ])art each of the seventh and the ninth. These structures are
almost identical with the ccn-responchng ones of a mounted specimen
of the species in the United States National Museum.

Fig. I represents a transverse section of the rim of the carapace
taken between the sixth and the seventh peripherals.

HAY— A FOSSIL ALLIGATOR SNAPPER. 455

EXPLANATION OF THE PLATES.
]\Iacrochelys te.mmin'ckii, fossil.

Ill the figures of these plates the sutures between the bones are repre-
sented by narrow white lines; the seams between the horny scutes by wider
dark lines. All the figures are two-fifths of the natural size.

Plate XVIII. •
Fig. I. Skull seen from above.
Fig. 2. Skull seen from below.

Plate XIX.

Fig. I. Fragment of right side of carapace, c. p. 4, part of fourth costal
plate, or bone; behind it is a part of the fifth, mar. 8. mar. g, the eighth mar-
ginal horny scute and a part of the ninth, per. 6. per. 7, the sixth and seventh
peripheral bones, but only a part of each. .?. mar. 4. the fourth supramarginal
horny scute; in front of it is a part of the third. The third costal horny
scute area occupies the portions of the costal plates present, except the hinder
border of the fifth.

Fig. 2. Skull seen from the right side.

The American Philosophical Society

Announces that an Award of the

HENRY M. PHILLIPS PRIZE

will be made during the year 191 2 ; essays for the same to
be in the possession of the Society before the first day of
January, 1912.

The subject upon which essays are to be furnished by
competitors is :

The Treaty-making power of the U^iited States
and the methods of its enforcemeiit as affect-
ing the Police Pozvers of the States.

The essay shall contain not more than one hundred thousand words, ex
eluding notes. Such notes, if any, should be kept separate as an Appendix.

The Prize for the crowned essay will be $2,000 lawful gold coin of the
United States, to be paid as soon as may be afteLthe award.

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Essays may be written in English, French, German, Dutch, Italian,
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No treatise or essay shall be entitled to compete for the prize that has
been already published or printed, or for which the author has received
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All essays must be typewritten on one side of the paper only.

The literary property of such essays shall be in their authors, subject to
the right of the Society to publish the crowned essay in its Transactions
or Proceedings.

The essays must be sent, addressed to

The President of the American Philosophical Society,
No. 104 South Fifth Street, Philadelphia, Penna., U. S. A.

Corrigendum

■ In Mr. Berry's article on "A Study of the Tertiary
Floras of the Atlantic and Gulf Coastal Plain" in No. 199,
the sketch maps on pages 306 and 308, by mistake, have
been transposed and that on page 308 should have been
printed on page 306 and that on page 306 should have been
printed on page 308. The legends are correctly numbered,
but Fig. I has been printed over the legend of Fig. 2 and
vice versa.

Members who have not as jet sent their photographs to the Society will
confer a favor by so doing; cabinet size preferred.

It is requested that all correspondence bj addressed

To THE Secretaries of the

AMERICAN PHILOSOPHICAL SOCIETY

104 South Fifth Street

• Philadelphia, U. S. A.

PROCEEDINGS

OF THE

American Philosophical Society

HELD AT PHILADELPHIA

FOR PROMOTING USEFUL KNOWLEDGE

Vol, L. September, 191 i; No. 201.

CONTENTS.

An Hydrometric Investigation of the Influence of Sea Water on the Distribu-
tion of Salt Marsh and Estuarine Plants. By John W. Harshbergbr, Ph. D. 457

The Cost of Living in the Twelfth Century. By Dana C. Munro 497

An Ancient Protest Against the Curse of Eve. By Paul Haupt 505

Stated Meeting, Jufiuary 6, igii iii

Stated Meeting, February 3, igii iv

Stated Meeting, March 3, igu iv

Stated Afeeting, April y, igii iv

General Meeting, April 20^ 21, 22, igii v

Special Meetings May 2, igii xH

PHILADELPHIA

THE AMERICAN PHILOSOPHICAL SOCIETY
104 South Fifth Street

1911

Corrigendum

In Mr, Berry's article on " A Study of the Tertiary
Floras of the Atlantic and Gulf Coastal Plain" in No. 199,
the sketch maps on pages 306 and 308, by mistake, have
been transposed and that on page 308 should have been
printed on page 306 and that on page 306 should have been
printed on page 308. The legends are correctly numbered,
but Fig. I has been printed over the legend of Fig. 2 and
vice 7^ersa.

Members who have not as jet sent their photographs to the Society will
confer a favor by so doing ; cabinet size preferred.

It is requested that all correspondence be addressed

To THE Secretaries of the

AMERICAxNT PHILOSOPHICAL SOCIETY
104 South Fifth Street

Philadelphia, U. S. A.

5 \^\^

PROCEEDINGS

OF THE

AMERICAN PHILOSOPHICAL SOCIETY

HELD AT PHILADELPHIA
FOR PROMOTING USEFUL KNOWLEDGE

Vol. L September-December, 1911 No. 201

AN HYDROMETRIC INVESTIGATION OF THE INFLU-
ENCE OF SEA WATER ON THE DISTRIBUTION OF
SALT MARSH AND ESTUARINE PLANTS.

(Plates XX and XXL)
By JOHX W. HARSHBERGER, Ph.D.
(Read April 23, 19 lo.)

Elsewhere^ I have discussed the general character of the vegeta-
tion of the salt marshes of the northern New Jersey coast and the
factors controlling the distribution of marsh plants in that area.
This earlier study was based largely on physiographic and floristic
considerations, although reference is made on page 379 of that paper
to the use of the hydrometer in the investigation of the actual influ-
ence of sea water, or salty soil, on the distribution of a limited num-
ber of plants. The investigation begun in 1909 has been continued
until sufficient facts have accumulated to warrant their publication.

The use of a special kind of hydrometer was suggested as a
simple but efficient method of investigating the salt content of salt
marsh soils and of the estuarine water which, at first strongly saline,
becomes largely diluted, as it mingles with that of streams flowing
in a seaward direction. This is the first actual use of the hydrometer

^ Harshberger, John W., " The Vegetation of the Salt IMarshes and of
the Salt and Fresh Water Ponds of Northern Coastal New Jersey," Pro-
ceedings Academy of Natural Sciences of Philadelphia, 1909, 373-400, with
6 figures.

PROC. AMER. PHIL. SOC., L. 20I EE, PRINTED AUG. 25, I9II.

457

458

HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

in phytogeographic and phytoecologic investigation. The method is
appHcable not only to a study of salt marsh soils, but also to an
investigation of salt lakes and alkaline soils, which are found in
many parts of our western arid districts and in other parts of the
world (Fig. i). The use of the hydrometer supplements, if it does

JyphA aogustlfpllA.
. Pi>Jch»a.e.antphocala.

OpaajiW«.ter> Belmar.

.At/JDlex.baataifl

.El Ma^J t prr^jie an. . . .
Snsrlina_«tclcta-Diacii..

&■ S^Ucornia herbacea

Temperature
SaJ! M.ar%h.ManasQi/an.

, XympKaaa odoxAU

'•?25 Ju.ncu^Ger^d,..
I^^^---D.,.ichl,s,picau

1.035

I-P?9.Bi>ierLak<>jSiberia

1.046

050

S(ULL«l<iB.Shi.ra,i.

_,, Persia

Sal.t.Marth, Belntar

. aumroec Tewo, Saa.

VVater.Belmar

11.1083 SallLake.Utah
l5.2^«Sallne

Fig. I. Special hydrometer and thermometer used in the investigation
of the salt marsh vegetation of the New Jersey coast. The names of plants
are arranged along the scale to graphically represent the maximum density of
salt water to which these plants are subjected in their marsh environment.
Other data are given for comparison.

not replace, the employment of the more expensive and cumbersome
apparatus which determines by electric means the salt content of
soils. Althouijh this investigation was made in the salt marshes of

• 1910.] ON THE DISTRIBUTION OF PLANTS. 459

northern coastal Xew Jersey, the results obtained are equally appli-
cable to the same salt marsh species as they are found distributed
along our eastern Atlantic coast. For stretching from the Bay of
Fundy along the New England, middle and southern Atlantic coasts,
as far south as Jupiter Inlet in Florida, are extensive salt marshes
covered with a vegetation which consists with minor dififerences of
almost the same and characteristic species.

Possible Methods of Investigations.

There are four possible methods open to the investigator of the
salt content of salt marsh soils and estuarine waters. These methods
have been used by chemists, soil analysts and plant physiologists.

Method of Titration. — The determination of salt content by volu-
metric analysis has been the favorite one of chemists. For this
purpose, a tenth-normal silver nitrate volumetric solution is used,
prepared as follows: Dissolve 16.869 grams of silver nitrate, which
previous to weighing has been pulverized and dried in a covered
porcelain crucible in an air-bath at 130° C. (260° F.) for one hour
in sufficient water to measure at 25° C. {'jy° ¥.), exactly 1,000 c.c.
This solution is kept in dark amber-colored, glass-stoppered bottles,
carefully protected from dust and sunlight. A tenth-normal potas-
sium bichromate test solution is prepared by dissolving 4.8713 grams
of pure potassium bichromate, which has been pulverized and dried
at 120° C. (248° F.) in sufficient water to measure at 25° C. {"jy"
F.) exactly 1,000 c.c. To a definite volume of salt water, sufficient
potassium bichromate test solution is added to impart a yellow tint,
then the tenth-normal silver nitrate solution is slowly added from a
burette, stirring or agitating until the mixture acquires a permanent
tint, due to the formation of red silver chromate. The fluid to be
tested must be neutral, as free acids dissolve the silver chromate.
The cubic centimeters of silver nitrate solution used must now be
multiplied by .005850 Fresenius (.005837 Sutton, .005806 National
Dispensatory) to give the weight of the sodium chloride, because
.005850 Fresenius (.005837 Sutton, .005806 N. D.) grams of sodium
chloride is the equivalent of one cubic centimeter of tenth-normal

460 HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

silver nitrate volumetric solution.- This is the method adopted I
am told by the botanists at Johns Hopkins University in studying
the salt marsh vegetation of Maryland, the results of which investi-
gation have not yet been published.

Method of the Electric Bridge. — The Bureau of Soils, United
States Department of Agriculture, adopted some years ago the prin-
ciple of the slide wire bridge to the measurement of the salt content
of soils.^ The earlier instruments have been described in various
bulletins and the results obtained with them are scattered through
various publications of the bureau. Since 1899, when the electric
bridge was put first into practical use, various improvements have
been made, so that the improved instrument is the result of the
experience gained by its use in the actual field study of soils. The
use of the electric methods for determining the soluble content of
a soil depends on the fact that the electric current is conducted by
the salt in solution and that the conduction of the solution, or con-
versely, its resistance to the passage of the current, is largely deter-
mined by its concentration. The magnitude of current that will pass
is increased by an increase of salt in solution ; or the resistance to
the passage of the current decreases with the increase of salt. The
experience gained by the use of the modified instrument is embodied
in the recent bulletin of the Bureau of Soils noted above and its
general utility in the study of alkali soils, the salt content of irriga-
tion and seepage waters is given.

Method of Plasnwlysis. — It is a well-known physiologic fact that
dilute solutions of potassium nitrate, sodium chloride and cane sugar
cause a removal of water from living plant cells, so that the proto-
plasm contracts away from the inside of the cell wall. The per-

" Consult Hare, Hohart A., Caspari, Charles, Rusby, H. H., " The
National Standard Dispensatory," 1905, 1684; Fresenius, C. Remigius, "A
System of Instruction in Quantitative Chemical Analysis," 1894, 430; Sutton,
Francis, "A Systemic Handbook of Volumetric Analysis,"' 1890, 124; Fraps,
G. S., see bibliography.

^ Davis, R. O. E., and Bryan, H., "The Electrical Bridge for the De-
termination of Soluble Salts in Soils," Bull. 61, Bureau of Soils, 1910, where
reference is made to previous bulletins; Cannon, W. A., "On the Electrical
Resistance of Salt Plants and Solutions of Alkali Soils," The Plant World,
II, ia-14.

I9I0.] ON THE DISTRIBUTION OF PLANTS. 461

centage of substance in solution necessary to cause plasmolysis varies
not only with the plasmolyzing substance, but also with the plant
used in the experiments. The protoplasm in some plants plasmolyzes
quickly ; in other cases with difficulty, so that stronger solutions are
necessary to produce a change in the more refractory plants. If
we know, therefore, that a certain percentage strength of sodium
chloride in solution will produce plasmolysis in say the cells of the
staminal hairs of Tradescantia, then if raw or diluted sea water be
used and a similar plasmolysis occurs, the percentage of sodium
chloride in the sea water must be equivalent to that of the salt solu-
tion known to produce similar plasmolytic effects. A comparative
table can be constructed by which the varying percentages of sea
water can be ascertained. An extensive literature, part of it noticed
in the bibliography, is concerned with such plasmolytic studies.'*

Hydrometric Method. — The use of the hydrometer in determin-
ing the salt content of salt marsh soils suggested itself to me, as a
simple but efficient method of making a phytogeographic survey of
the vegetation of salt marshes upon purely ecologic lines. The
advantage of the hydrometer is that it is light, can be carried easily
from place to place and lends itself to immediate use, the record
depending upon two simple readings, one of specific gravity and one
of temperature. The hydrometer is plunged into a vessel contain-
ing the water to be tested.

Styles of Hydrometers. — After a simple hydrometer had been
used in a number of preliminary tests, search was made for a hydrom-
eter which would record accurately the density of sea water. It was
found that there are many kinds of hydrometers in use to test acids,
alcohol, alkali, ammonia, bark liquor (tannometer ), beer, benzine,
chlorine, cider, coal oil, ether, gasoline, glycerine, milk (lactometer),
naptha oil, salt solutions (salimeter). silver solution, sugar, sugar
and syrup. Some are constructed with Baume's scales, others with
Richter and Trolle's scales and those used to test sugar wath Balling's
and Brix's scales. Finally, after testing several different kinds of

■* Drabble. E., and Lake, H., " The Osmotic Strength of Cell-sap in
Plants growing under Different Conditions," The Nezv Phytologist, October,
1905, 189; Duggar, B. M., "The Relation of Certain Marine Algae to
Various Salt Solutions," Trans. Acad. Sci. St. Louis. XVI., 473-479.

462 HARSHBERGER— INFLUENXE OF SEA WATER [April 22,

hydrometers, one was obtained which fulfiUed all the conditions of
experimentation most perfectly. The hydrometer purchased of
Arthur H. Thomas Company is one designed to test the specific
gravity of liquids heavier than water. The scale reads from 0.995
to 1.065 ^"d is divided into single units and half units (Fig. i).
For example, beginning at i.oooo, the divisions of the scale read
as follows: 1.0005, i.ooio, 1.0015, 1.0020, 1.0025, 1-0030, 1.0035,
1.0040, 1.0045, T.0050. The last figure is the next prominent figure
on the scale printed in black letters. Altogether 140 separate read-
ings can be made from this scale, and if the observer wished to test
the salinity of the water of Salt Lake, Utah, the length of the scale
would have to be increased to the point indicated in Fig. i, and the
size of the bulbs would have to be increased correspondingly. There
are three bulbs blown in the hydrometer tube. The lower one is
the sinker with metallic mercury. The middle one carries the mer-
cury of the thermometer, which is inclosed in the third and upper
bulb. The thermometer scales reads from — 5° C. to +45° C, and
is divided into degrees with the fifteenth marked in red. With this
instrument temperature and specific gravity can be determined
simultaneously.

Corrcciions to Readings. — In actual use, the experimenter finds
that the hydrometric readings vary with the temperature of the
water, and that to make the results harmonious all of the readings
for specific gravity must be reduced to the uniform temperature of
15° C. No table exists by which the reduction can be made directly
without calculation. Such a table for all temperature degrees and
degrees of specific gravity is a desideratum. A mechanic rule, or
sliding scale, might be constructed from which corrected readings
might be taken directly by adjusting the movable parts of the scale
to corresponding degrees of specific gravity and of temperature. In
the absence of such a table and mechanic scale after a prolonged
search through theoretic text-books of chemistry, the following one
was discovered, which enabled me to standardize all of the readings
made by the hydrometer by reference to the specific gravity at

15° C. ' '

I9I0.]

OX THE DISTRIBUTION OF PLANTS.

463

Table for the Reduction of Specific Gravity at any Temperature to
THE Specific Gravity at 15° C.

(Table B, Landolt-Bornstein Physikalisch-Chemische Tabellen, Berlin. 1905,

page 323.)

" Reducktion der Dichte d- auf die Dichte bei 15° nach den Beob. von
4
Dittmar" (Challenger Exped.), Ekman (J^ctensk. Handl., 1870), Lenz u.

Reszof {Mem. Petersb., 1881), Thorpe u. Riicker (Phil. Trans., 166, II;

1876), Tornoe (Norw. Atlantic Exped., 1880) berechnet von Makarof (J.

Russ, Phys. Chcm. Gcs., 23, 30; 1891). Auszug.

0°

5°

10°

15°

20°

25°

30°

Dest ^Yasser

0.99988

99979

99974

99915

99828

99714

99577

Seewasser

1.00077

00087

00060

00000

999 II

99796

99659

"

1.01130

01120

01075

01 000

00898

00774

00630

I. 02 I 82

02152

02090

02000

01886

01751

01600

"

1.03228

03179

03102

03000

02876

02732

02572

This fact shoitld be noted in connection with the use of the above
table, viz.. the specific gravity of a sample of sea water is the num-
ber representing its weight as compared with an equal volume of
pure water at the same temperature. The latter is usually called
1. 000 so that the specific gravity of a sample of sea water may be
some such number as 1.025. The density is the weight in grams of
one cubic centimeter of water at the temperature in situ (^°) com-
pared with that of i c.c. of pure water at 40° C. It is usually

expressed as D-^. The salinity is the total weight in grams of the

4
matter dissolved in i.ooo grams of water.

Mathcmatic Calculation. — Through the kindness of a graduate
student, ]\Ir. John C. Bechtel. to whom my thanks are due, I was
relieved of the labor of making the mathematic calculations neces-
sary to reduce the hydrometric readings to 15° C. His method of
procedure is herewith given in a sample case.

To determine density at 15° C. of salt water whose density at
23° is 1.0155.

From the table we see that this corresponds to a solution whose
density at 15° lies between i.oi and 1.02.

We therefore find figures for density of salt water at 23°, if
density at 15° is i.oi, and also if density is 1.02.

Density at 20° is 1.00898 for first and 1. 01886 for second.

464 HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

Density at 25° is 1.00774 for first and i. 01 751 for second.
For first, the change in density for 5° is

1 .00898 — 1 .00774 = .00 1 24.

For 3° it is f of .00 1 24 = .00740.

Hence density is 1.00898 — .00740^1.00824 at 23°.

For second change in density for 5° is

1.01886 — 1.01751 = .00135,

For 3° it is f of .00135^.00081.

Hence density at 23° is equal to density at 20° — loss for 3° or
1.01805.

We now have densities at 15° as i.oi and 1.02 as limits and from
observations we see that at 2^^° the density of our solution is 1.0155.

We also have this proportion which will give a sufficiently
approximate result :

H 3? is the density of this solution at 15°

y — I.OI I -0155 — 1.00824

1.02 — I.OI 1. 01 805 — 1.00824

3' — I.OI .00726

.01 .00981 '

3' = I -o I + .0074,
3'= 1. 01 74,

therefore density at 15° = 1.0174.

As the above computation is a rather long one and must be made
for each of the actual readings obtained by the hydrometer, it has
been thought advisable to give the entire set of original readings at
various temperature and the corrected specific gravity at 15° C.
Such a table may enable future workers in the same field to make
their corrections at once by omitting the long computation otherwise
necessary'. The numbers in the first column of the table refer to
the observations as recorded in the field note book and which have
been added as subnumbers to the specific gravities placed on the map
of Shark River and Bay which comprises Fig. 4 of the text.

igio.]

OX THE DISTRIBUTION OF PLANTS.

465

Table Giving Hvdrometric Observations on Salt ;Marsh Plants of New
Jersey with Corrections at 15° by Mr. John C. Bechtel.

Observed

Sp. Gr.

Observed

Sp. Gr.

No.

Sp. Gr.

Temp. °C.

at 15°.

No.

Sp. Gr.

Temp. °C.

at 15°.

71

I-OI55

23

1. 0174

108

1.0005

14

1.0004

72

1. 0160

23

1. 0179

109

1.0025

24

X.OO44

73

1. 0180

21

I. 0194

IIO

1.0025

20

1.0034

75

1. 0170

20

I.01S2

112

1. 0120

28

1. 0153

76

I. 0175

19

I.01S4

"3

I 0035

25

1.0057

77

1.0260

29

1.02996

114

I. 0015

25

1.0036

78

I 0150

22

1. 0166

"5

1. 0000

23

1. 0016

80

1. 0165

>9

I. 0174

116

0.9990

25

I.OOII

81

1. 0160

26

I.01S8

117

1.0005

21

I. 0016

82

I 0105

21

I.OII7

118

1. 0160

27

I.OI81

83

1.0090

20

I. 0102

119

1. 0165

26

1. 0193

84

1.0020

20

1.0029

120

1. 0160

27

I.OI9I

85

1. 0010

20

1. 0019

121

1-0415

24

86

1. 0000

18

I 0005

—

1. 0150

25

I. 0175

87

1. 0140

25

1. 0164

124

I.OI55

29

I. 0192

88

1.0030

23

1.0046

12^

I. 0010

22

1.0024

89

I. 0000

22

1 . 00 1 4

126

I. 0190

23

1. 0210

90

I. 0000

20

1 . 0009

127

I. Olio

21

1.0022

91

1.0005

20

1. 00 1 4

128

1.0035

22

1.0049

92

1. 0140

22

I. 0156

129

1.0205

23

1.0225

93

1 .0205

20

I. 0217

130

I-0255

20

1.0267

94

1.0200

20

I. 0212

131

1.0065

20

1.0075

95

I. 0215

19

1.0224

132

I. Olio

19

1. 01 So

96

1.0050

19

1.0058

133

1.0250

21

1.0265

97

I. Olio

19

I.OI18

134

1.0205

22

1.0222

98

1. 0165

18

1.0172

135

1.0250

21

1.0265

99

I. 0215

18

1.0223

136

1.0240

20

1.0252

loo

1. 0180

18

I. 0187

—

I. 0210

22

1.0224

lOI

I. 0210

21

1.0224

137

1.0245

27

1.0278

102

1.0245

20

1.0257

138

1. 02 1 5

24

1.0238

.103

I. 0185

20

1. 0196

139

1. 0180

25

1.0205

104

1. 0195

21

1.0209

140

1.0055

20

1.0065

107

1. 0150

25

1. 0175

After having discussed the theoretic methods, we must next con-
sider the actual study of the vegetation in the field by the use of
the hydrometer.

Aids to Field Sttidy. — The equipment which was carried into the
field for the study of the edaphic conditions under which salt marsh
vegetation grows was accommodated in a light basket and consisted
of a meter measure, reading to decimeters, centimeters and milli-
meters ; a narrow, but deep, glass cylinder to hold the water upon
which the specific gravity determinations were made ; a tin dipper
to collect the water and a field note book. A narrow trenching
spade was carried in the hand and by this spade it was possible to

466 HARSHBERGER— INFLUENCE OF SEA WATER [April 22.

dig deep holes in the tough resisting marsh sod. The water for
study was dipped either directly from holes in the marsh or taken
from the ocean and open bays along the New Jersey coast. The hole
was dug in all cases deep enough to allow the soil water to perco-
late into it, and upon this water the specific gravity readings were
made. The region especially traversed in this way extended from
INIanasquan Inlet on the south to Sandy Hook Bay on the north, and
thus an insight was obtained of the problems concerned in the distri-
bution of the various species of salt marsh plants.

Field Observations and Data.

Altogether sixty readings were made with the first style of sali-
nometer used. This tvpe had such a small range of scale divisions
that it was discarded as being too inaccurate for the purposes of the
salt marsh investigation where the total salt content of the water
increased, or decreased, by almost inappreciable amounts. Although
manv of these observations are of interest, they are not incorporated
here. The second style of In^irometer was like the final one adopted,
as to the divisions of the scale, but it lacked a thermometer. The
data obtained by this hydrometer are considered here, but they are
onlv of comparative value, because they lack the accuracy of the
later readings which were made for both specific gravity and tem-
perature. They are of value because they give habitat relationships
not included in the more accurate data obtained later.

For the above reasons the field observations will be considered
under two heads : ( i ) the readings made by the hydrometer without
the thermometer, and (2) the readings which include both hydro-
metric and thcrmometric measurements.

Hydronictric Readings zcithont Thcnnoiiictcr. — The readings
which are numbered consecutively from 1-70 inclusive are arranged
geographically as afl:"ording more interesting comparative data. They
stand as follows : Beginning in the north readings were obtained
along the Shrewsbury River, starting at the railroad bridge connect-
ing Highland Beach with the Navesink Highlands proper. Plum
Island, where the first measurements were made, is a small island
back of the Sandy Hook peninsuula in Sandy Hook Bay. Undoubt-

I9I0.] ON THE DISTRIBUTION OF PLANTS. 467

edly, the water of this bay is less strongly saline because influenced
by large fresh water rivers, such as the Hudson River.

55. Spartiiia stricta iiiaritiina. association on Plum Island. Sp.
gr. 1.016.

56. Baccharis haliniifolia, association with Saliconiia hcrbacca,
Siiaeda iiiaritiina, water covering plants at high tide two inches deep.
Sp. gr. 1.0155.

57. Salt Pond on Plum Island, fringed by Spartiiia stricta iiiari-
tiina. Sp. gr. 1.016.

59. Water from a hole two feet deep in tension strip between
Spartiiia stricta maritiiiia and Baccharis haliniifolia. Sp. gr. 1.018.

60. Water from hole eighteen inches deep in middle of a Spar-
tiiia patens association. Sp. gr. 1.020.

61. Water from a hole eighteen inches deep on the tension line
between Spartiiia patens and Spartiiia stricta inaritinia. Sp. gr. 1.019.

62. Water from a hole on the tension line between 5"/'ar/;'//a /'afr^.y
and Baccharis haliniifolia. Sp. gr. 1.0185.

64. W^ater from a hole eighteen inches deep in the middle of an
association of Saliconiia iiiiicroiiata, Liinoniuni caroliniannm, Spar-
tiiia patens and near by on the same level Atriple.v hastata, Snacda
Iiiaritiina and Baccharis haliniifolia. Sp. gr. 1.003.

The following observations were made in ascending the Shrews-
bury River toward Pleasure Bay :

53. Salt water at Highlands Pier. Sp. gr. 1.019.^

66. Water surrounding Spartiiia stricta inaritinia fringing beach
in front of the Navesink Highlands. Sp. gr. 1.0185.

68. At the confluence of the Navesink and Shrewsbury rivers
with a lot of Fucns z'esiciilosus attached to pilings and also Spartiiia
stricta inaritinia. Sp. gr. 1.0185.

69 and 70. At this point water submerged an association of
Linioninin carolinianitin, Sitaeda iiiaritiina, Spartiiia patens, Sali-
coniia herbacea, Plaiitago inaritinia and Atriple.v hastata. Sp. gr.
1.018.

Ascending the Shrewsbury River, the head of navigation is
reached at Pleasure Bay. From here to the head of the bay the

^ For comparison, the sea water from the ocean at Behnar read sp.
gr. 1.0215 at Temp. 20.6° C. corrected to 15° the sp. gr. := 1.0224.

468 HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

water becomes gradually fresher and the salt marsh vegetation is
replaced gradually by fresh water marsh plants.

T,2. Water from Pleasure Bay at the head of navigation. Sp.
gr. 1. 010.

33. Water from ditch two feet deep in middle of Spartina patens
association. Sp. gr. i.oio.

35. Water at head of small ditch with Scirpus pungens, Cicitta
maculata, Scirpus robustus. Sp. gr. 1.005.

^y. Slue with Baccharis haliuiifolia and Spartina stricta niari-
tima. Sp. gr. i.oio.

42. Hole in salt meadow on tension line between Jiincus Gerardi
(cut for hay) and an association of Scirpus pungens, Pluchea cam-
phorata, AtripJe.v hastata and Spartina patens on the other side. Sp.
gr. 1.005.

44. Water from bases of plants of Typha angustifolia and Scir-
pus pungens. Sp. gr. 1.015.*'

45. Water at third bridge above Pleasure Bay in the middle of
an association of Spartina stricta maritima, Scirpus pungens, S. ro-
bustus. Sp. gr. 1.005.

46. Above the fourth bridge in middle of a Spartina stricta mari-
tima association. Sp. gr. 1.0005.

47. Here a pure association of Scirpus robustus. Sp. gr. 1.0005.

48. Association of Zizania aquatica and Scirpus robustus. Sp.
gr. 1.0005.

50. Water from inner edge of an association of Typha angusti-
folia (tall), Peltandra virginica and Cicuta maculata. Sp. gr. i.ooo.

51. Muddy cold water from a hole in an association of Sagittaria
latifolia {=S. I'ariabilis) , Cicuta maculata, Typha angustifolia,
Polygonum sagittatum. Sp. gr. 1.0015.

52. Water from channel under last bridge. Sp. gr. 1.0015.
The fact that such salt marsh species as Spartina stricta maritima

mingles with fresh-water marsh species under almost fresh-water
conditions is to be explained by the occasional inundation of such
plants by more strongly saline water at exceptionally high tides, so
that the exceptionally high tides enable the salt grass to persist sur-
rounded by fresh-water marsh species. The salt marsh species can

" Prolnibly due to evaporation.

I9I0.]

ON THE DISTRIBUTION OF PLANTS.

469

withstand fresh water better than the fresh-water species can salt
water. These latter plants are able also to withstand an occasional
flooding, although normally they are controlled by fresh water. This
is probably to be accounted for by the resistance of the leaves that
surround the stem, while the roots are in practically fresh water,
which saturates the ground and prevents the entrance of salt water
into it for some time. The occasional flooding of salt water is not
for a sufficiently long time to efifect the character of the ground
water in which the roots of such plants as Sagittaria latifolia, Cicnta
maculata grow.

The observations at Belmar began with an estimation of the
salinity of the ocean water. The readings from 4-19 are interesting

Fig. 2. Basin-like slue along Fifth Avenue, Belmar, N. J., fringed by
salt marsh vegetation and backed by forest trees. Several of the stations
for hydrometric determinations were chosen along this shore.

because they were made while Shark River Inlet was closed to the
sea by a sand bar.

2. Sea water from surf at Belmar. Sp. gr. 1.0215 at 20.6° C.
(69° F.) ; corrected to 15° C. Sp. gr. = 1.0224.

4. Water in Shark River Inlet flooding Spartina stricfa uiarit'una
association. Sp. gr. 1.015.

5. Water from channel opposite B Street, Belmar. Sp. gr.
1.0185.

470 HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

7. Water from seaward end of marsh island in Shark River.
Sp. gr. 1. 017. With Spartiiia stricta niaritiuia.

8. Water submerging J uncus Gcrardi. Sp. gr. 1.016.

9. Water covering Spartiiia patens. Sp. gr. 1.017.

12. W^ater in large slue along Fifth Avenue, Belmar. Sp. gr.
1.016.

13. Water from bay at Casino Landing, where a rise of eighteen
inches was noted after the inlet closed. Sp. gr. 1.0175.

These several readings show the condition of salinity when the
inlet through which the tidal salt water enters Shark River is closed
and the salt water thus inclosed is diluted by rain and river water
until the river shows a perceptible rise of eighteen inches above the
level of normal high tide. In such rivers the salt marsh vegetation
for considerable periods of time is exposed to fresh water, which
w^ould ultimately control, if the inlet would remain permanently
closed. But when the inlet is reopened the original conditions of
salinity are restored by the tidal flow of sea water in and out of the
landlocked bay. This is an interesting corroboration of the recent
work of D. W. Johnson,^ who believes that the indications of appar-
ent subsidence are due to fluctuations in the tidal level due to a
change in the configuration of the coast. During the closure of
Shark River there was a rise of water level in the river which might
account for the rise in the height of the salt marsh layers. After
the causal influences had been obliterated, an examination of the
layers of salt marsh soil would indicate, according to the older views,
a total submergence of the coast line equal to the depth of newly
formed marsh peat.

The observations on the salinity of the water at the western end
of Newberry (Stockton) Lake, an arm of Manasquan River, are
of interest as displaying the edaphic conditions which control the
distribution of Typha angustifolia. The size of this plant is also
directly conditioned by the amount of salinity as measurements later
to be presented will show. However, if we begin near the outlet

^Johnson, D. W., "The Supposed Recent Subsidence of the Massa-
chusetts and New Jersey Coasts," Science, N. S., XXXII., 721-723; Bartlett,
H. H., " Botanical Evidence of Coastal Subsidence," Science, N. S.,
XXXIII., 29^31 ; Johnson, D. W., Science, XXXIII, 300-302.

igio.]

OX THE DISTRIBUTION OF PLANTS.

471

of the lake where the cat-tails occur, the following series of readings
are suggestive.

28. (Position I.) Association of Typlia angiistifolia — base of
plant covered by water at high tide. Sp. gr. 1.0145.

2/. (Position III.) Typlia angustifolia. Sp. gr. 1.014.

26. (Position \ .) Typlia angustifolia. Sp. gr. 1.014.

25. Position A'l.) Typlia angustifolia with Atriplcx hastata.
Submerging water with sp. gr. 1.012.

24. (Position A'lla. ) Association of Typlia angustifolia, Atri-
plcx hastata, Saliconiia hcrhacca, Spavtina stricta niaritinia. Sp.
gr. 1.0135.

27, (Position A'll^.) Association of Typlia angustifolia, Scirpus
lacustris, S. pungcns. Sp. gr. 1.0125.

22. Outer edge of Typlia angustifolia association at the head of
the lake. Sp. gr. 1.0115.

21. Head of Newberry Lake at inner edge of dense masses of
Typlia angustifolia with Hibiscus mosclicutos (third lot). Sp. gr.
1.0050.

Influence of Saline Water on Typlia angustifolia. — Before begin-
ning a consideration of the data obtained by using the hydrometer
and thermometer combined, it is important to consider the influence

Fig. 3. Cat-tail, Typha angustifolia. at the head of Stockton Lake near
Sea Girt, N. J. The tall plants are growing at Position III.

472

HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

of the varying salinity of the water upon the plants which are sub-
jected to the dilTerent densities of salt water. For this purpose, I
have chosen Typha angustifolia because it seems to show in a marked
degree the influence of the variation in the saline environment. Six
series of measurements were taken at this plant. Three series are
based on plants from Stockton Lake and three upon plants from
Pleasure Bay.

In all the measurements the height of the plant is measured to
the top of the fertile part of the terminal spike. The upper sterile
and staminate portion is included, but it is only temporarily present.
Measurements are metric.

First Series. Typha oiigustifolia from Stockton Lake Shore. (Position

L) Sp. gr. 1.0145.

No.

Height of
Plant.

Length of
Spike. 9 .

Breadth of
Spike, 9 .

Width of Third
Leaf from Top.

No. of Leaves.

Sterile

Dry.

Green.

Part.

I

.929

.0S7

.016

.004

6

6

.020

2
1

1.030
Broken

.075
Broken

.020

Broken

.006
.004

6

7

5
5

.025

4

1.353
1.015

.124
.080

.020
.019

.006
.006

6
8

6

5

•015
.018

6

8

1. 119
1. 1 00

.090
.098

.018
.022

.005
.006

7

7

6

5

.026
.022

7
9

1. 124
1.008

.082
.076

.020
.018

.005
.004

9
6

4
6

.027
.020

10

.922

.075

.019

.005

4

6

.021

Series of heights: .922, .929, 1.008, 1.015, 1.030, i.ioo, 1.119, 1.124, 1.353-
Arithmetic mean ^ 1.066.

Length of spikes, $: .075, .076, .080, .082, .087, .090, .098, .124. Arithmetic
mean =: .089.

Breadth of spikes, ?: .016, .018, .019, .020, .022. Arithmetic mean =: .019

Second Series. Typha angustifolia from Stockton Lake Shore. (Position

II.) Sp. gr. 1. 014.

Height of
Plant.

Length of

Spike, 9 .

Breadth of
Spike, 9 .

Width of Third
Leaf from Top.

.005

No. of Leaves.

Sterile

No.

Dry.

Green.

Part.

I

1.398

.090

.023

7

6

.023

2

1.288

.i'3

.023

.006

8

5

.015

3

'.430

.091

.021

.006

10

5

.032

4

1.473

.095

.025

.007

13

7

.023

■S

1.545

.145

.024

.007

7

5

.013

6

1.293

.087

.022

.006

7

5

.015

7

1.572

.0S4

.023

.007

9

5

.025

8

1.413

.130

.025

.008

9

5

.024

9

1.300

.126

.023

.008

6

5

.021

ID

1.560

.120

.025

.007

12

6

.020

1910.]

ON THE DISTRIBUTION OF PLANTS.

473

Series of heights: 1.288, 1.293, i-300, 1.398, 1.413, i430, 1.473, 1-545, i-56o,
1.572. Arithmetic mean = 1.427.

Length of spikes, $: .084, .087, .090, .091, .095, .113, .120, .126, .130, .145.
Arithmetic mean ^ .108.

Breadth of spikes, ?: .021, .022, .023, .024, .025. Arithmetic mean = .023.

Third Series. Typha angustifolia from Stockton L.\ke Shore (Position
III.) AT Head of Lake. Sp. gr. 1.005.

No

Height of

Length of

Breadth of

Width of Third

Sterile

Plant.

Spike, 9 .

Spike, 9 .

Leaf from Top.

Dr>-.

Green.

Part.

I

2.026

.164

.023

.009

8

7

.016

2

2.108

.162

.025

.010

10

7

.024

3

1.862

.154

.018

• Oil

9

5

.016

4

1.882

.146

.022

.010

7

6

.026

S

1.803

.169

.022

.010

9

7

.031

6

1.789

.141

.025

.Oil

8

8

.022

7

1.668

.161

.020

.009

8

6

.027

8

1.678

.138

.021

.008

10

6

.028

9

1.920

.182

.024

.009

7

7

.030

10

1. 815

.166

.026

.008

6

6

.012

Series of heights: 1.668, 1.678, 1.789, 1.803, i-8i5, 1.862, 1.882, 1.920, 2.026,
2.108. Arithmetic mean = 1.885.

Length of spikes, $: .138, .141, .146, .154, .161, .162, .164, .166, .169, .182.
Arithmetic mean = .158.

Breadth of spikes, $: .018, .020, .021, .022, .023, .024, .025, .026. Arith-
metic mean = .022.

If we take the arithmetic means of the plant heights, lengths of
pistillate spike portions and breadths of pistillate spike portions of
the thirty plants taken from three separate localities along the shores
of Stockton Lake, we will appreciate the influence of the saline con-
ditions of the soil upon the relative size of the plants of these
three sets.

Mean Dimensions of 30 Plants.

Height of
Plant.

Length of
Spike, 9 .

Breadth of
Spike. 9 .

Sp. Gr.

Position I.
Position II.
Position III.

1.066
1.427

I 855

.089
.108

.158

.019
.023
.022

1. 0145
1. 0140
1.0050

This table clearly shows that the cat-tails in fresh water are much
taller than those growing under more saline conditions, and this
applies not only to the heights of the plants, but to the other dimen-
sions as well.

PROC. AMER. PHIL. SOC, L. 201 FF, PRINTED AUG. 25, I9II.

474

HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

The next three series of Typlia angustifolia were collected along
the shores of Pleasure Bay under somewhat similar conditions to
those along the shores of Stockton Lake.

Fourth Series. Typha angustifolia in Salt ]^Iarsh. Sp. gr. 1.015.

No.

Height of

Length ot

Breadth of

Length of

Plant.

Spike, 9 .

Spike, 9 .

Dry.

Green.

Sterile Part.

I

.788

.110

.005

4

7

.025

2

.962

.209

.010

7

2

•035

3

.980

.100

.005

5

6

.040

4

.910

."9

.010

7

4

•035

5

.888

.135

.009

6

3

.020

6

.768

.096

.006

5

4

.063

7

.925

.120

.007

6

5

.1008

s

.857

.100

.009

6

4

.100"

9

1.005

• 119

.006

3

6

.104"

10

.904

.130

.006

4

6

.010

Series of heights: .768, .788, .857, .888, .904. .910, .925, .962, .980, 1.005.
Arithmetic mean =; .898.

Length of spikes, $: .096, .100, .110, .119, .120, .130, .135, .209. Arithmetic
mean := .127.

Breadth of spil<es, ? : .005, .006, .007, .009, .010. Arithmetic mean = .007.

Fifth Series. Typha angustifolia near Middle Part of Upper Pleasure

Bay. Sp. gr. 1.005.

No. of Leaves.

No.

Height of
Plant.

Length of
Spike, 9 .

Breadth of
Spike, 9 .

Length of

Dry.

Green.

Sterile Part.

I

.910

.102

.010

5

4

.029

2

1.030

.112

.012

6

4

.046

3

1. 130

.128

.014

4

6

•034

4

.879

.090

.Oil

5

4

.027

.s

.877

.089

.010

4

5

.042

6

•833

.087

.007

6

4

•045

7

•932

.081

.009

5

4

.040

8

1. 102

.115

.014

5

5

•034

9

1.096

.114

.013

5

6

.030

10

1. 180

•133

.015

5

5

■034

Series of heights: .833, .877, .879, .910, .932. 1.030, 1.096, 1.102, 1.130,
1. 180. Arithmetic mean = .996.

Length of spikes, ?: .081, .087, .0S9. .090, .102, .112, .114. .115, .128, .133.
Arithmetic mean = .105.

Breadth of spikes, $: .007, .009, .010, .011, .012, .013. .014, .015. Arith-
metic mean ^ .011.

Measurements include sterile and staininate part of the spike.

IQIO.]

ON THE DISTRIBUTION OF PLANTS.

475

Sixth Series. Typha angustifolia Collected at Head of Pleasure Bay.

Sp. gr. i.ooo.

No. of T-cavp.;.

Height of

Length of

Breadth of

Length of

No.

Plant.

Spike, 9 .

Spike, 9 .

Dry.

Green.

Sterile Part.

I

1.564

•145

.015

5

8

.028

2

1.642

193

.016

5

6

.040

3

1.430

147

.020

6

5

.032

4

1.688

117

.018

6

6

•035

5

1-543

148

.019

6

6

.031

6

1.467

134

.018

5

5

.052

7

1-6x5

144

.019

6

7

.032

8

1^307

148

.020

5

6

.030

9

1.632

173

.016

7

6

.021

lO

1-657

182

.015

5

5

.026

Series of heights: 1.307, 1.430, 1.467, 1.543, 1.564, 1.615, 1-632, 1.642, 1.657,
1.688. Arithmetic mean ^1.554.

Length of spikes, ?: .117, .134, .144. -MS- -U/- -U8. .1/3, -i^J, .193.
Arithmetic mean = .154.

Breadth of spikes, $: .015, .016, .018, .019, .020. Arithmetic mean = .018.

Constructing a table of means of the last three series, we dis-
cover that the heights of the cat-tails and the dimensions of the spike
increase with the decrease in the salinity of the water.

Mean Dimensions of 30 Plants.

Height of
Plant.

Length of
Spike, 9 .

Breadth of
Spike, 9 .

Sp. Gr.

Position IV.
Position V.
Position IV.

.898

-996

1-554

.127
•105
•154

.007 I.015

.Oil 1.005

.018 I. COO

Now, if we combine the two tables which demonstrate the mean
dimensions of the sixty measured plants collected from six widely
diverse positions, we will see at a glance that Typha aiujnstifoha
when found in soil with saline conditions, as indicated by the specific
gravity of the soil water, is reduced in size compared with other
plants growing under more, or less, fresh-water conditions. All of
the dimensions of the plants are influenced, but not in corresponding
proportions, and it is also noteworthy that the cat-tails in a more
saline soil are not only smaller in size, but show a more yellowish-
green appearance than the taller, darker green plants controlled by
fresh water.

476

HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

Table Showing Influence of Salinity of Water on the Dimensions of
Sixty Plants of Typha angustifolia. Measurements in Meters.

Habitat.

Posi-
tion.

Specific
Graivty.

Height of
Plants.

Mean

Height of

Plants.

Length
of Spikes,

Mean
Length of
9 Spikes.

Breadth
of Spikes,

Mean
Breadth of
9 Spikes.

Most saline
Medium saline.
Fresh water.

I.

IV.

II.

V.

III.

VI.

1.0145
I. 0150

1. 0140
1.0050

1.0050
I. 0000

1.066
.898

1.427
.996

1-855

1-554

.982
1. 211
1. 710

.089
.127

.108

.105

.158
•154

.108
.106
.156

.019
.007

.023
.Oil

.022
.018

.013
.017
.020

Having presented the results obtained by using the hydrometer
without the attached thermometer, it next concerns this paper to
discuss and tabulate the results obtained by the hydrometer so con-
structed as to combine with the hydrometer scale a thermometer,
whereby density and temperature can be estimated at the same time.
This enables us then to reduce all of our specific gravity determina-
tions to the uniform temperature of 15° C, so that the second series
of observations are far more accurate as giving the actual salinity
of the water which bathes the roots of a number of typic salt marsh
plants. In all of the following data, the corrected specific gravity
determinations are placed within brackets.

Observations with Hydrometer and Attached Thermometer.

The numbered data given below were collected at three localities
convenient to Belmar, N. J., easily reached by trolley, viz., Manas-
quan Inlet, Wreck Pond and Shark River. The same plan was
adopted of working from the most saline conditions of environment
to the least saline conditions and the gradual change of the vegeta-
tion will be noted, if we follow the sequence of the numbered sta-
tions at which hydrometric readings were made.

81. Salt water in north arm Manasquan River. Thoroughfare
fringed with Spartina stricta luaritiina and Saliconiia hcrbacea. Sp.
gr. 1.016; temp. 26°. [Sp. gr. 1.0188.]

71. Salt Creek at bridge back of Manasquan Life Saving Station.
Meadow sod is here 45 chl deep, with sand below. Sp. gr. 1.0155 ;
temp. 23°. [Sp. gr. 1.0174.]

I9I0.] ON THE DISTRIBUTION OF PLANTS. 477

^2. Salt Creek, nearer Manasquan Inlet, below the bridge. Here
is Spartina stricta maritima associated with Salicornia herhacea.
Sp. gr. 1.0160; temp. 27,°. [Sp. gr. 1.0179.]

y^,. Hole dug in middle of Spartina patens association. Water
reached at 82 cm. At same level of the marsh, but in a slightly dif-
ferent position were found Salicornia herhacea and Liniotiiuni caro-
linianiim. Sp. gr. 1.018; temp. 21°. [Sp.,gr. 1.0194.]

74. Hole dug in the middle of a patch oi Salicornia herhacea, sur-
rounded by Distichlis spicata, Limoninm carolianuni. No free water
obtained after digging to a depth of 82 cm.

75. Water from ditch cut through Spartina stricta niaritinia,
Spartina patens, Salicorjiia herhacea. Sp. gr. 1.017; temp. 20°.
[Sp. gr. 1.0182.]

76. Hole 56 cm. deep in association of Spartina stricta maritima,
Salicornia herhacea, Distichlis spicata. Sp. gr. 1.0175; temp. 19°.
[Sp. gr. 1.0184.]

yy. Small marsh pool (7 cm. deep) with Spartina stricta mari-
tima, Salicornia herhacea, Spartina patens. The high specific gravity
of the water in this pool due to strong evaporation. Sp. gr. 1.026;
temp. 29°. [Sp. gr. 1.02996.]

78. At head of drainage ditch with Spartina patens. Sp. gr.
1.015; temp. 22°. [Sp. gr. 1.0166.]

79. Hole in Juncus Gerardi association which fringes Spartina
patens inwardly and touches an association of Bacchoris halimifolia,
Paniciim virgatum, Solidago sempervirens.

80. At head of drainage ditch with Juncus Gerardi (as in 79).
Sp. gr. 1.0165; temp. 19°. [Sp. gr. 1.0174.]

82. Water from a drainage ditch in Juncus Gerardi association.
Soil 49 cm. deep. Sp. gr. 1.0105 ; temp. 21°. [Sp. gr. 1.0117.]

The observations at Wreck Point were made on August 13,
1909, six days after the inlet, which had been closed for some time,
was opened. The first three tests were made of the water from the
pond proper without relating them to the nearby vegetation.

83. Water at trolley bridge. Sp. gr. 1.0090; temp. 20°. [Sp.
gr. 1. 01 02.]

84. Water at railroad bridge. Sp. gr. 1.0020; temp. 20°. [Sp.
gr. 1.0029.]

478 HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

85. \\'ater at carriage bridge. Sp. gr. i.ooio; temp. 20°. [Sp.
gr. 1.0019.]

87. Water in Spart'uia stricta luaritiiiia association at high tide,
just above the railroad bridge. Sp. gr. 1.0140; temp. 25°. [Sp.
gr. 1. 01 64.]

88. Water in Spartina stricta maritima association at high tide,
at carriage bridge. Sp. gr. 1.0030; temp. 23°. [Sp. gr. 1.0046.]

86. Stream entering Wreck Pond at tension Hne between salt
marsh and fresh-water marsh at low tide. Here were found Spar-
tina stricta maritima in broken patches being gradually replaced by
Scirpns lacustris, Scirpus pungens and Spartina polystachya. Sp.
gr. 1. 0000; temp. 18°. [Sp. gr. 1.0005.]

89. Water in Spartina stricta maritima association along high
bank fronted with Pauicum virgatum. Sp. gr. i.oooo; temp. 22°.
[Sp. gr. 1.0014.]

The observations begun on Shark River were delayed by a severe
northeast shifting to southeast storm, August 17. 1909, so that the
tides were exceptionally high and all of the typic salt marsh plants
along Shark River were submerged. Unusual opportunities were
presented, therefore, to determine the salinity of the water which
flooded the salt marsh species.

93. Frontal association of Spartina stricta maritima near open-
ing of the inlet. Sp. gr. 1.0205 ; temp. 20°. [Sp. gr. 1.0217.]

94. Somewhat back from inlet water covering Spartina stricta
maritima, Solidago scmpcri'ircns. Sp. gr. 1.020; temp. 20°. [Sp.
gr. 1. 02 1 2.]

95. All of the salt marsh associations of plants on the Belmar
side of Shark River, such as Spartina patens, Jnnciis Gcrardi, Sali-
cornia hcrhacca, including A triplex hastata and Myrica carolinensis,
submerged excepting the tops of Spartina stricta maritima and the
low sand dunes on which grow Ammophila arenaria, Baccharis
lialimifolia, Solidago scmpcri'ircns. Sp.gr. 1.0215; temp. 19°. [Sp.
gr. 1.0224.]

97. Some distance back from the inlet along Fifth Avenue,
Belmar, the following plants were found submerged : Scirpus pun-
gens, Cicuta maculata, Hibiscus moscheutos, Paniciim virgatum,

I9I0.]

OX THE DISTRIBUTION OF PLANTS.

479

Baccharis halimifolia. Sp. gr. i.oii; temp. 19°. [Sp. gr. 1.0118.]
It will be seen by reference to the above observations that even
the least typic of the salt marsh species which usually grow subjected
to the influence of fresh water are placed occasionally under more
trying conditions during exceptionally severe storms, when they are
subjected to the action of almost pure sea water. On August 19,
1909, the storm having subsided, the normal flow of the tide in and

Fig. 4. ]\Iap of Shark River and Bay, N. J., showing stations at which
hydrometric determinations of the salinity of the water were made. Numbers
indicate specific gravities at the points directly under the first figure and the
subnumbers indicate the observational stations as noted in the paper and in
the original field note-book.

out of the inlet was reestablished and the following series of obser-
vations were then made.

126. \\'ater from lagoon inside jetty at Shark River Inlet at
high tide. Sp. gr. 1.0190; temp. 22)°. [Sp. gr. 1.0210.]

127. Hole dug 20 cm. deep in an association of Scirpns pniigciis,
Solidago sempervircns, Spartina patens, Atriplcx hasfata, Sitaeda
inaritima. Water rising from a sandy gravel. Sp. gr. 1.0010; temp.
21^ [Sp. gr. 1.0022.]

130. Water from a hole 46 cm. deep in an association of Jiinciis

480 HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

Gerardi, Liuionium carolinianmii. Sp. gr. 1.0255; temp. 20°. [Sp.
gr. 1.0267.]

131. Water from hole 28 cm. deep in an association of Distichlis
spicata, SaUcornia hcrhacca. Sp. gr. 1.0065; temp. 20°. [Sp. gr.
1.0075.]

133. Water from a hole 50 cm. deep in a Spartina strict a mari-
tinia association. At 20 cm. a hard pan of gravel stones was
reached, then a layer of sand was passed and at the bottom a hard
gravel layer. Sp. gr. 1.025; temp. 21°. [Sp. gr. 1.0265.]

134. Water from Shark River. Sp. gr. 1.0205; temp. 22°. [Sp.
gr. 1.0222.]

135. Water from a ditch along back of Shark River marsh,
Belmar side, lined with Spartina stricta niaritima, Spartina patens,
SaUcornia herhacea. Sp. gr. 1.0015; temp. 20°. [Sp. gr. 1.0024.]

136. Water from hole in marsh 61 cm. deep at the base of a
clump of BaccJiaris halimifolia associated with Distichlis spicata,
Aster tcnuifoliiis, SaUcornia herhacea, Limoniwn caroUnianum. Top
soil brown and loose, subsoil sandy. Sp. gr. 1.024; temp. 20°. [Sp.
gr. 1.0252.]

137. Water covering surface of the marsh in middle of a Dis-
tichlis spicata association with Spartina stricta maritima, SaUcornia
herhacea, Linioiiinin caroUnianum. Sp. gr. 1.0245 ; temp. 2y° . [Sp.
gr. 1.0278.]

138. The last test recorded here was to determine if there was
any difference in the salinity of the water between ebb and flow.
Tide receding rapidly. Sp. gr. 1.0215; temp. 20°. [Sp.gr. 1.0238.]

loi. Shark River Bay water in channel through salt marsh
bounded by Spartina stricta maritima and Spartina jnncca. Sp. gr.
1.021 ; temp. 21°. [Sp. gr. 1.0224.]

102. Hole dug in marsh 30 cm. deep in an association of 5' /'ar/Z/ux
stricta maritima, Limoninm caroUnianum, SaUcornia herhacea. Sp.
gr. 1.0245; temp. 20°. [Sp. gr. 1.0257.]

103. Hole dug in marsh 30 cm. deep in an association of Dis-
tichUs spicata and Linioinuni caroUnianum. Sp. gr. 1.0185; temp.
20°. [Sp. gr. 1. 01 96.]

104. Hole dug 20 cm. deep in a pure association of Jnncus
Gerardi. S]). gr. 1.0195; temp. 21°. [Sp. gr. 1.0209.]

igio.]

ON THE DISTRIBUTION OF PLANTS.

481

107. \\'ater at head of north arm of Shark River Bay (see map,
Fig. 4) in middle of an association of Spartina stricta maritima and
Spartina patens. Sp. gr. 1.0150; temp. 25°. [Sp. gr. 1.0175.]

Fig. 5. View of salt marsh island fringed with Spartina stricta maritima
and covered by associations of Spartina patens, Juncus Gerardi, Distichlis
spicata, etc. Shark River, New Jersey.

109. Contracted portion of the north arm of Shark River Bay,
where Spartina stricta maritima breaks up into patches between
which grow Scirpus pnngcns, Spartina patens and NympIi(raodorata.
Sp. gr. 1.0025; temp. 24°. [Sp. gr. 1.0044.]

no. Water at base of a patch of Spartina polystaehya. Sp. gr.
1.0025; temp. 20°. [Sp. gr. 1.0034.]

112. \\'ater from hole 20 cm. deep at the base of an association
of Phragniites communis (see Fig. 4). Sp. gr. i.ooio; temp. 28°.
[Sp. gr. 1.0153.]

113. Water in upper portion of the south arm of Shark River
Bay. Sp. gr. 1.0035; temp. 25°. [Sp. gr. 1.0057.]

114. Water from middle of Spartina stricta marititna associa-

482

HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

tion, south arm of Shark River Bay at carriage bridge. Sp. gr.
1. 001 5 ; temp. 25°. [Sp. gr. 1.0036.]

115. Water from last extensive patch of Spartiiia stricta mari-
tiiiia merging with TypJia aiKjitstifolia. Sp. gr. i.oooo; temp. 23°.
[Sp. gr. 1.0016.]

116. Water tested at the head of the south arm of Shark River
Bay (Fig. 6), where the vegetation becomes continuous and the
patches of Spartiiia stricta iiiaritiina are divided by narrow hnes of
Scirpiis fluriatiUs, Typha aiigustifolia, Zicaiiia aquatica, touching a
forest growth of Nyssa sylz-atica. Sassafras varUfoJuim, Piniis

Fig. 6. Association of Spariina stricta VLaniima in upper part of the
south arm of Shark River Bay, showing blending and transition of salt-water
and fresh-water vegetation.

rigida, Qncrcus prinns. 0. alba. Sp. gr. 0.9990; temp. 25°. [Sp.
gr. 1. 001 1.]

119. Water 60 cm. deep at a point along south shore of Shark

igio.]

ON THE DISTRIBUTION OF PLANTS.

483

River Bay with J^iUisncvia spiralis abundant. Sp. gr. 1.0165 ; temp.
26°. [Sp. gr. 1.0193.]

120. Hole dug in a marsh at base of a ckmip of Peltandra znr-
ginica. Sp. gr. 1.016; temp. 27°. [Sp. gr. 1.0191.]

124. Water from a marsh lagoon at base of a steep bkiff sub-

~^^ 'Hi

.-

fc-vv . r^ i

^^

g/.?^k^^

^I^^^IH^H

UBH

I^^^P

Ha-- • ^-ju'^ TS

^^^^9H

1

1

Fig. 7. Clump of Paiiicum inrgatum growing along shore of Stockton
Lake controlled by fresh water.

jected to evaporation between the daily tides. Lagoon surrounded
by Spartina stricta maritima. Sp. gr. 1.0155; temp. 29°. [Sp. gr.
1. 0192.]

The above observations give the geographic data upon which the
study of the distribution of the salt marsh species has been based.
It will be seen that proceeding from the ocean up the various bays
and inlets there is a general decrease in the saltiness of the controlling
water as revealed bv the use of the hvdrometer and the amount of

I

484 HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

salt which controls in general the habitats of the several species is
graphically shown in the sketch map until a point is reached where
the salt marsh vegetation mingles with that of the fresh water
marshes until it is gradually replaced by vegetation controlled by
fresh water (Fig. 7).

Sequence of Hydrometric Readings.
It is important to give now in sequence the various specific gravi-
ties corrected to 15° C. to which readings are appended, the name

of the plant or the names of the plants subjected to that specific

density of salt water. The subnumber indicates in all cases the

number of the observation in the series previously given.

1.02996-- Spartina stricta maritima, Spartina patens, SaUcornia
herbacca.

1.0278O137 Distichlis spicata, Spartina stricta maritima, SaUcornia
herhacea, Limonium carolinianum.

1.0267O130 J uncus Gcrardi, Limonium carolinianum.

1.0265O133 Spartina stricta maritima, Limonium carolinianum.

1.0257O102 Spartina stricta maritima, Limonium carolinianum, SaU-
cornia herhacea.

1.0252O136 Baccharis halinii folia. Aster tenuif alius, SaUcornia her-
hacea, Limonium carolinianum, Atriplex hastata.

i.0224ioi Spartina stricta maritima, Spartina patens, ocean water
from surf at Belmar.

1. 0224^36 water in thoroughfare.

1. 0217003 water at high tide. Shark River Inlet, covering base of
Spartina stricta maritima.

1.0209O104 J uncus Gcrardi.

1.0196O1,,.. Spartina patens, SaUcornia herhacea, Limonium caro-
linianum.

1.0193O110 VaUisneria spiralis.

1.0192O124 Spartina stricta maritima.

1.0191O1J8 Spartina stricta maritima, Scirpiis pungens.

1.0191O100 Peltandra virginica.

i.oi880yi water in channel connecting Manasquan River and Stock-
ton Lake fringed with Spartina stricta maritima, SaUcornia
herhacea.

I9I0.] ON THE DISTRIBUTION OF PLANTS. 485

1. 01820.5 Spartina stricta maritima, Spartina patens, SaUcornia
herbacea.

1.0180O132 Spartina stricta maritima.

1.01790^2 Spartina stricta maritima, SaUcornia herbacea.

1.0175O107 Spartina stricta maritima, Spartina patens, Distichlis
spicata.

1.0174OS0 Jnncns Gcrardi.

1.01660-8 Spartina patens.

1.0164O8- Spartina stricta maritima.

1. 01 530^12 Phragmites communis.

i.oi 17030 Jiinciis Gerardi.

1.0075O131 Distichlis spicata, SaUcornia herbacea.

1.0065O140 Scirpiis inarifi)na, Pluchca camphorata.

1.00490,08 Spartina stricta maritima, Spartina patens.

1.0046088 Spartina stricta maritima.

1.0044O109 Spartina stricta maritima, Spartina patois, Scirpiis pun-
gens, Nymphcca odorata.

1.003601^^ Spartina stricta maritima.

1.0034OJ10 Spartina polystachya.

1.0024O133 Spartina stricta maritima, Spartina patens, SaUcornia
herbacea.

1.0024O105 Spartina stricta maritima.

i.00220i,7 Scirpiis pungens, SoUdago scmpcri-irens, Atriplex has-
tata, Spartina patens, Siiaeda maritima.

i.ooi60ijg Spartina stricta maritima, Typlia angustifoUa.

1.0016O11- Phragmites communis.

1.0014089 Paniciim virgatum, Spartina stricta maritima.

1.0014O91 Scirpus lacustris, Scirpus pungens, Spartina polystachya.

1.01189. Hibiscus moscheutos.

i.ooiiOiie Scirpus fliiviatilis, Zi::ania aquatica, Typha angustifoUa.

1.0005086 Spartina polystachya, Scirpus lacustris, Scirpus pungens,
Spartina stricta maritima.

1.0004O108 iron-sulphur spring water.

486

HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

Sequence of Salt Marsh Plants Arranged According to
[Maximum Density of Salt Water.

In order to make what follows more general and intelligible, the
specific gravity of saline solutions at 15° C. and the corresponding
percentages of sodium chloride in solution is displayed in the fol-
lowing table for converting specific gravities of salt solutions into
per cent, of sodium chloride taken from Landolt-Bornstein, " Physi-
kalisch-Chemische Tabellen," p. '^22.

Per Cent.

^-;

Per Cent.

^'5°
^-^

0.5
I.O

1-5
2.0

2-5

1.0034
1 . 0064
I. 0100
I. 0137
1. 0173

3-0
3-5
4.0

4-5

50

1.0209
1.0246
1.0282
I 0319
1035s

Now, if we place the salt marsh plants according to their ability
to withstand degrees of salinity of water, we can appreciate better
the factors which control their distribution in the bays and estuaries
of the New Jersey coast. The first figures show the greatest degree
of salinity to which the various species are subjected and the second
number indicates the limit toward the fresh water end of the series.
The range varies in the difit'erent species to a marked extent.

Spart'ma stricia uiaritiiiia 1.02996-1.00140

Spartina patens i. 02996-1. 00220

Salicornla licrbacca i. 02996-1. 00240

Distichlis spicata i .02780-1 .00750

Limonium caroHnianum 1.02 780-1. 01 940

J uncus Gcrardi i .02670-1. on 70

Baccharis haliuiifolia 1.02520-

Astcr tciiuifoliiis 1.02520-

A triplex hastata 1.02520- 1.00220

Ocean water, Belmar 1.02240-

'^I'allisneria spiralis i. 01 930-1. 00000

Scirpus pungciis i.oi 910- 1. 00000

*Peltandra virginica 1.01910-1. 00000

*Phragmites communis i. 01 530-1 .00160

^Hibiscus moscheiitos i.o 11 80- 1.00500

Pluchea camphorata 1.00650-

Xymphcca odorata i. 00440- i.oooco

Spartina polystachya 1.00240-1.00050

I9I0.] ON THE DISTRIBUTION OF PLANTS. 487

Solidago sctnpervircns 1.00220-

Siiaeda maritima 1.00220-

Typlia angustifolia i. 001 60-1. 001 10

Panicurn virgatiim 1.00140-

Scirpiis laciistris 1.00140-1.00050

Scirpus fluz'iafilis i.ooi 10-

Zizania aquatica i. 001 lo-i. 00000

All of the plants above the line are able to withstand a maximum
of over I per cent, of sodium chloride in the salt water, and may be
reckoned as the true salt marsh species, while J'allisneria spiralis,
Hibiscus moscheittos, Phragmites communis, and Peltandra virginica
are excluded, because their habitat is frequently an inland, not a
salt marsh one. All below the line, according to the accurate data
presented for the first time, are not able to grow in salt water the
sodium chloride content of which approximates i per cent.''

By this arrangement we are able to segregate the plants found on
the Xew Jersey salt marshes, for although apparently occupying the
same geographic position and growing under similar conditions of
environment, yet we can divide them into salt marsh species, those
that are adapted to a saline soil with from 1-4 per cent, of sodium
chloride, and those less well adapted to a saline soil, but which are
to be classed among the plants found in fresh-water swamps. Oc-
casionally, as the list shows, we will meet with such non-saline plants
in a typic saline environment. This is to be explained as in the cases
of Vallisneria spiralis, Hibiscus moscheutos, Phragmites com-
munis, and Peltandra virginica by their adaptation to more saline
conditions. Again there are fresh-water marsh species found on
salt marshes, but their presence is to be explained by the fact
revealed by the hydrometer, that while the surface marsh soil
may be strongly saline, the subsoil is controlled by fresh water
which flows outward from the higher ground under the salt marsh
sod. Into the subsoil controlled by fresh water the roots of a num-
ber of plants of fresh-water habitat grow, notwithstanding the fact
that they are growing in the middle of a salt marsh. Appearances
here are deceptive and the peculiar behavior of these plants per-
plexed me until the hydrometer showed the reason for the presence

^ See preceding table of percentages and specific gravities with which the
above figure may be compared.

488 HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

of such plants on the salt marsh. The first eleven plants of the
preceding list may be looked upon as true saline species, while the
other plants of the list are those which are typically found under
fresh-water conditions of environment. These plants have accom-
modated themselves to a soil of some salinity as tested by the hy-
drometer. On the other hand, the degree of accommodation of the
typic salt marsh species is indicated. The following show the widest
range of accommodation : Spartlna stricta niaritima, Spartina patens,
Jnncus Gcrardi, while Salicornia Jierhacea, Distichlis spicata, Limo-
niuiii caro!i)iianum show a small range of accommodation. As a
result one is justified perhaps in believing that this difl:'erence in the
degree of accommodation accounts in part^" for the general and con-
trolling distribution of Spartina stricta iiiariti)!ia, Spartina patens
and Juncus Gerardi, which are most prevailingly present in the salt
marshes of the Atlantic coast, while Salicornia herbacea, Limonium
caroliniaiium, with less power of accommodation and smaller size,
are rarely controlling, but form small associations, or are intermin-
gled with the other salt marsh species. The salt grass Distichlis
spicata, although it never grows in areas of great extent, yet is
usually found where it grows in nearly exclusive association. This
power of accommodation seems to be an inherent property of proto-
plasm and it varies within wide limits for different kinds of plants.
The lower plants seem to have a greater power of accommodation,
the higher plants a less degree. Professor G. J. Peirce, of Stanford
University, has undertaken to study the behavior of some ponds
on the flat shore of San Francisco Bay into which salt water is
pumped for the manufacture of salt. The water evaporates during
the dry season, leaving an accumulation of salt on the bottom and
sides of these ponds, and from a minimum specific gravity of 1.06000
in the rainy season the concentration rises in the course of three or
four months until the specific gravity reaches 1.22500. A small
crustacean (Artemia) and the larvse of some flies are the only ani-
mals living in these brines, but there are unicellular plants, bacteria
of various sorts, chromogenic and other kinds, Clilaniydonio)ias-like

" The vegetative habits of these plants with powerful rootstocks and
methods of seed distriI)ntion must also be considered as important factors.

1910.] OX THE DISTRIBUTION OF PLANTS. 489

algx, both green and brown, which are found in various stages of
their existence at different times in these ponds/ ^

Sections of Salt ^NIarsh Soil.
A detailed study of the various sah marsh soils along the Xew
Jersey coast was begun coincidently with a study of the salt content
of the soil by means of the hydrometer, but these observations have
not been carried to completion. A few notes on some of the condi-
tions observed may not be out of place. Taking a sample of the
muck soil in the middle of an area of the ^lanasquan salt marsh
covered with Spartiiia patens, we find its total depth to be about 104
cm. From this a block of peat was cut 57 cm. thick. The first 21
cm. at the top was of one color, consisting of 12 cm. of a fibrous
root material and 9 cm. of a less strongly fibrous layer. The first
12 cm. represent the remains of the cover plant, for this part gave
rise to new plants of Spartiiia patens when the soil was laid flat
along the side of the cut. Below these upper fibrous layers followed
a lighter brown fibrous layer, 14 cm. thick, and then 7 cm. of a black
fiberless layer followed by 16 cm. of a brown fibrous layer where
the hollow pipe-stem-like remains of the rootstocks of Sparfina
striata maritiina occur. This section of peat clearly indicates a suc-
cession of vegetation types. The marsh deposits began in submerg-
ing salt water, because the remains of Spartiiia sfricta inaritiina are
found in the lower layers. Then sand and clay material was depos-
ited on which Spartiiia patens began to build up successive layers of
peat. This was formerly explained by a change of coast line, but
the suggestions of Johnson (see ante) that it may indicate a change
of tidal'level seems to be worthy of consideration in a study of the
deposits of peat in the salt marshes of Xew Jersey, where the coast
line is under constant change so as to profoundly influence the
height of the tides in the rivers and embayments along the shore.

Economic Coxsideratioxs.
The salinity of the water, which can be determined by the hy-
drometer, is the determining factor in the distribution of salt marsh

" MacDougal, D. T., " Annual Report of the Director," Dept. Bot. Re-
search Carnegie Institution of Washington, 1910, 56.

I'ROC. AMER. PHIL. SOC, L. 20I GG, PRINTED AUC. 26, I9II.

490 HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

plants, although the texture of the soil, its aeration and the lines of
marsh drainage are influential factors. In the reclaiming of these
salt marshes, as has been done so successfully along the Bay of
Fundy^- in Nova Scotia, the hydrometer affords a ready means of
determining accurately what amelioration has been secured by ditch
drainage. The same method of research can be applied to the study
of the alkali soils in many parts of the world, especially in our west-
ern states, and the farmer can test the presence or absence of salts
and their relative amounts in the soil.

Some years ago Scofield^'* determined the salt-water limits of
wild rice, with a view to ascertaining the areas which could be suc-
cessfully devoted to the cultivation of this valuable but long-neglected
food grass. After investigations by means of the electric bridge
along Chesapeake Bay and the Potomac River, Scofield assumed that
the salt-water limit of wild rice is approximately represented by 0.03
of the normal solution of sodium chloride, while the concentration
of the water of Chesapeake Bay is about 0.28 of a normal solution
of sodium chloride. So that in establishing cultures of wild rice
along the coast streams it is highly important that the concentration
of the water covering these areas be determined either by the electric
method or by the hydrometer, which is simple and equally applicable.
Similarly Fraps^* determined that 0.3 per cent, of salt is dangerous
to the true rice plant where rice farms along the coast are supplied
with water pumped from streams occasionally subjected to salt water
influences.

The distribution of animals is also profoundly influenced by the
salinity of the water. C)ccasionally extensive oyster beds are ruined
by flooding with fresh water, and the oysterman can readily deter-
mine the influential density of the water which covers his submerged
plantation by means of the hydrometer. Two years ago the follow-
ing was printed in the Trenton Ez'cning Times of Friday, August

'^ Harshberger, John W., " The Reclamation and Cultivation of Salt
Marshes and Deserts," Bulletin Geographical Society of Philadelphia, July,
1907.

"Scofield, Carl S., "The Salt Water Limits of Wild Rice," Bull. 72.
U. S. Bureau of Plant Industry, 1905.

'* Trgps, G. S., " The Effect of Salt Water on Rice," Texas Agricultural
Experiment Station, Bull. 122, June, 1909.

I9I0.] ON THE DISTRIBUTION OF PLANTS. 491

27, 1909, and this excerpt shows the bearing of this study upon the
Delaware River fisheries. I quote in full :

Millions of crabs are moving up the Delaware River from the sea. Their
coming is due to the protracted drought, which has reduced the downward
strength of the current in the river and caused the saline waters of the
Atlantic to reach the harbor of Philadelphia. For the first time in many
years the Delaware River is brackish as far as Gloucester, the result of which
is that mullet, sea bass and porpoises may be seen every day above Chestei.
The crabs which are the kind generally caught off the coast are to be
found everywhere from the Delaware Breakwater to Philadelphia. For the
first time on record, a big catch was made yesterday off the Point House
piers, below Greenwich Point in the lower section of the city. Oldmans
Creek, Raccoon Creek on the New Jersey side of the river and other tribu-
taries of the river are alive with fish and crabs, and every day fishermen are
bringing to market big hauls made in sight of Dock Street market.

Boilers on river steamboats have to be watched carefully, as the salt in
the water causes constant foaming and more than ordinary diligence is re-
quired by marine engineers to prevent serious results to vessels for which
they are responsible.

In the latter case the use of an hydrometer, or salinometer would
indicate the dilution at which the foaming in the boilers no longer
took place and thus its use in such emergencies of navigation becomes
of great importance.

In the following bibiliography not all of the papers cited deal
directly with salt marshes, but they treat of the influence of saline
solutions in general upon animals and plants. In this list will be
found many important papers which represent the most modern
expression of opinion upon the accommodation of organisms to vary-
ing degrees of saline concentration.

BIBLIOGRAPHY.
Bartlett, H. H.
1909. Submarine Bog at Woods Hole. R/iodora. XL : 221-238. December,

1909.
1911. Botanical Evidence of Coastal Subsidence. Science. N. S., XXXIII.:

-9-31. January 6, 191 1.

Cannon, W. A.

1908. On the Electric Resistance of Solutions of Salt Plants and Solutions
of Alkali Soils. The Plant World, XL : 10-14, January, 1908.

Casu, A.

1907. Contribuzione alio studio della flora delle saline di Cagliari Parte III

Resistenza fisiologica della flora delle saline all" azione del sale marino.

Aniiali di Botanica, V.: 273-354 (iQO/). Review in Botanical Gazette,

XLIV. : 234, September, 1907.

492 HARSHBERGER—INFLUEXCE OF SEA WATER [April 22,

Clark, J. F.

On the Toxic Effect of Deleterious Agents on the Germination and
Development of certain filamentous Fung:'. The Botanical Gazette,
XXVIII.: 289-327; 278-404 with extensive bibliography.

Coast Advertiser, The.

1910. Closing of Shark River Inlet is Ruining the Oyster Beds, Belmar, X. J.,
Friday, July i, 1910.

Copeland, Edwin Bingham.

1897. 'i'he Relation of Xutrient Salts to Turgor. Tlie Botanical Gazette,
XXIV. : 399-416, December. 1897.

Dandeno, James B.

1901. The Application of Xormal Solutions to Biological Problems. The
Botanical Gazette, XXXII.: 229-237, with bibliography. (Reply by
Louis Kahlenberg, Bot. Gaz., XXXII.: 437-439, December, 1901.)

Davis, R. O. E., and Bryan, H.

1910. '!"he Electrical Bridge for the Determination of Soluble Salts in Soils.
Bull. 61, U. S. Bureau of Soils, 191c.

Dittmar, William.

1884. Report on Researches into the Composition of Ocean Water collected
by H. M. S. Challenger during the Years 1873-1876. Challenger Re-
port, Physics and Chemistry, I. (1884) : 25.

Drabble, Eric, and Lake, Hilda.

The Osmotic Strength of Cell-sap in Plants growing under Different
Conditions. The New Phytologist, IV. : 189.
1907. The Relation between Osmotic Strength of Cell-sap in Plants and their
Physical Environment. Bio-Chemical Journal, II. (1907).

Duggar, B. M.

'ihe Relation of Certain Marine Algae to Various Salt Solutions. Trans-
actions Academy of Science of St. Louis, XVI.: 473-489.

Fraps, G. S.

1909. The Effect of Salt Water on Rice. Bull. 122, Texas Agricultural Ex-
periment Station. June, 15C9.

Ganong, W. F.

1903. The Vegetation of the I'ay of Furdy Salt and Diked Marshes; an

Ecological Study. The Bntanical Gazette. XXXVI.: September, Xo-

vember, 1903.

Harshberger, J. W.

1907. Tile Rrclamalion and Cultivation of Salt Marshes and Deserts. BuT
lelin Gcoi^raf^hical Society of I'liiladclpJiia. Jul_\ . 1907.

1909. 'Ihe Vegetation of ,the Salt Marshes and of the Salt and Fresh Water
Ponds of Northern Coastal New Jersey. Proceedings Academy Natural
Sciences of Thiladclfhia. 1909: 373-400, with 6 figures.

Heald, F. D.

On the Toxic FTfect of Dilute Solutions of Acids and Salts upon Plants

I9I0.] ON THE DISTRIBUTION OF PLANTS. 493

Hill, T. G.

Observations on the Osmotic Properties of the Root Hairs of Certain Salt
^larsh Plants. The Xezc Phytologist, VII.: 133-142 (four tables and
text figures, 21-24).

1909. The Bouche d'Erquy in 1908. The NeiK.' Phytologist. VIII.: 97-103,
March. 1909.

Jensen, G. H.

1907. Toxic Limits and Stimulation Efifects of some Salts and Poisons on

Wheat. The Botanical Gazette, XLIII.: 11-44, January, 1907, with 3

pages of bibliography.

Johnson, D. W.

1910. The Supposed Recent Subsidence of the Massachusetts and New Jersey
Coasts. Science, N. S.. XXXII. : -/ii-yiT,, November 18, 1910.

1911. Botanical Evidence of Coastal Subsidence. Science, N. S., XXXIII.:
300-302, February 24, 191 1.

Kahlenberg, L.

1906. On the Nature of the Process of Osmosis and Osmotic Pressure with
Observations concerning Dialysis. Journ. Pliys. Chein.. X. (1906):
141-209. published in Transactions JVisconsin Academy, XV. (1906):
209-272. (Review in Bot. Gac. XLII.: 72, July, 1906.)

— with Austin.

1900. Toxic Action of Various Substances on Seedlirgs. Journal Phys.
Chemistry. IV. (1900): 533-537; 553-569- (Review in B t. Gaz ,
XXX.: 358, November, 1900.)

— and True, Rodney H.

On the Toxic Effect of Dilute Solutions of Acids and Salts upon Plants.
The Botanical Gazette, XXII.: 81-124.

Kronig, B., and Paul, T.

1897. Die Chemischen Grundlagen der Lehre von der Giftwirkung und
Disenfektion. Zcits. Hyg. Inf. Krankh., XX\'. (1897): 59.

Landolt-Bornstein.

1905. Table for Converting Specific Gravity of Salt Solution into Percent
Sodium Chloride. Physikalisch-Chemische Tabellen, 1905: 322.

Lillie, R.

1901. On the Differences in the Effects of various Salt Solutions on Ciliary
and iMuscuIar Movements in Arenicola Larva. Atnerican Journal of
Physiology, V. (1901) : 55-85-

1909. On the Connection between Stimulation and Changes in the Permea-
bility of Plasma Metnbranes of the Irritable Elements. Science, N. S.,
XXX. : 245-249. August 20, 1909.

Lipman, J. G.

1906. Reports of the Soil Chemist and Bacteriologist. Reports New Jersey
Experiment Station, 1906, 1907.

494 HARSHBERGER— INFLUENCE OF SEA WATER [April 22,

Loeb, J.

1900. Ueber die Becleutung der Ca- und K-Ioren fiir die Herzthiitigkeit.

rflilgcr's Archiv, LXXX. (1900) : 229-332.
1900. On ion-proteid Compounds, etc., I. Aincr. Journ. Physiol., III. (19:0) :

327-338-
1900. On the Different Effects of Ions, etc. American Journal of Physiology,

III. (1900), 383-396.

1902. Studies on the Physiological Effects of the Valency, etc., of Ions, I.
American Journal of Physiology, VI. (1902) : 411, 433.

Ueber die relative Giftigkeit von destillirtem Wasser, Zuckerlosungen,
etc. Pfliiger's Archiv, 97 : 394-409.

1905. Studies in General Physiology, II. (1905). 57^, 584. 7i5-

1906. The Stimulating and Inhibiting Effects of Mg and Ca upon the
Rhythmical Contraction of a Jellyfish ( Polyorchis). Journal of Bio-
logical Chemistry, I. (1906) : 427-436.

Loew, Oscar.

Niites on Balanced Solutions. The Botanical Gazette, XLVI. : 302.

1903. The Physiological Role of Mineral Nutrients in Plants. Bull. 45, U.
S. Bureau Plant Industry, 1903.

Magowan, Florence N.

1908. The Toxic Effect of Certain Common Salts of the Soil on Plants.
The Botanical Gazette, XLV. (1908) : 45-49.

Mayer, Alfred G.

1907. 'idle Cause of Rhythmical Pulsation in Scyphomedusae. Proceedings
Seventh International Zoological Congress, Boston, 1907.

1909. riie Relation between Ciliary and iMuscular Movements. Proceedings
of the Society of Experimental Biology and Medicine. VII. (1909) :
19-20.

1909. On the Use of Magnesium in Stupefying iNIarine Animals. Biological
Bulletin, XVII.: 341, October, 1909.

Meltzer. S. J., and Auer, J.

1908. The Antagonistic Action of Calcium upon the Inhibitory Effect of
Magnesium. American Journal of Physiology. XXI. (1908) : 403.

Olsson-Seffer, Pehr.

Relation of Soil and Vegetation on Sandy Sea Shores. The Botanical
Gazette, XLVII.: 85-126.

Osterhout, W. J. V.

1906. i lie Resistance of Certain }klarine Algae to Ch-nges i'l Osmotic
Pressure and Temperature. Pulilications of the University of Cali-
fornia, 11.: 1906, No. 8.

1906-7. On tlie Importance of Physiologically Balanced Solutions for Plants.
The Botanical Gazette, XLII. (1906) : 127-134: XLIV. (1907) : 259-272.

Osterhout, W. J. V.

1906. Extreme Toxicity of Sodium Cidoride ami its Prevention by other
Salts. Journal of Biological Chemistry (T906) : 363-369.

I9I0.] ON THE DISTRIBUTION OF PLANTS. 495

1900. Die Schutzwirkung des Natriums fiir Pflanzen. Jahrh. IViss. Bot.,

XLVI. (1900) : 121-136, figs. 3.
1909. On the Similarity in the Behavior of Sodium and Potassium. The

Botanical Gazette, XLVIII. (1909) : 98-104.

Oswald, W.

1905. Versuche iiber die Giftigkeit des Seewassers fiir Siisswassertiere.
Pfliiger's Arcliiv, CVI. (1905) : 568-598, pis. 2-7.

Scofield, Carl S.

1905. The Salt Water Limits of Wild Rice. Bull. 72, U. S. Bureau of Plant
Industr}-, 1905.

Smith, John B.

1902. The Salt ^larsh ]\Iosquito. Special Bull. T, Agricultural Experimental
Station, N. J., July 8, 1902.

1907. The New Jersey Salt Marsh and its Improvement. Bull. 207, N. J.
Agricultural Experiment Station, November 14, 1907.

Stevens, F, L.

1908. The Effect of Aqueous Solutions upon the Germination of Fungous
Spores. The Botanical Gazette, XXVI.: 377-406, December, 1908.

Transeau, Edgar N.

1908. The Relation of Plant Societies to Evaporation. The Botanical
Gazette, XLV. : 217-231, April, 1908.

True, Rodney H.

1898. The Physiological Action of Certain Plasmolyzing Agents. The
Botanical Gazette, XX\T. : 407-416, December, 1898.

— and Oglevee, C. S.

1905. The Effect of the Presence of Insoluble Substances on the Toxic Action
of Poisons. The Botanical Gazette. XXXIX.: 1-21, June. 1905.

Wahl, Robert, and Henius, Max.

1902. Comparative Table of Beaume Degrees and Specific Gravity according
to Bourgougnon. American Handy Book of the Brewing, Malting
and Auxiliary Trades (second edition), 1902: 1156.

Warming, Eug.

1897. Halofyt-Studier. Alem. de I'Acad. Roy. Sci. et des Lettres de Danemark.

Copenhagen 6me Ser. Sect., t. VIII., No. 4, 1897.
1908. Dansk Plantevaekst. I., Strand vegetation. 8vo, pp. vi + 325, figs. 154,

Copenhagen and Christiania, 1906. (Review in Bot. Gaz., XLV.: 55-

56, January, 1908.)

West, G. S.

1904. The British Fresh-water Algje. 1904: 55.

Willis, Clifford.

191 1. Alkali Soils. Bull. 126, South Dakota Agricultural Experiment Sta-
tion, April, 191 1.

496 HARSHBERGER— INFLUENCE OF SEA WATER

EXPLANATION OF PLATES.
Plate XX.

Fig. a. Typic salt marsh near Avalon, N. J., showing prominent growth
of salt marsh grass, Spartiiia stricta maritima, fringing open thoroughfare
and low sand dunes covered witli red cedar, Junipcrus virginiana, in the
distance.

Fig. B. Salt marsh near Avalon, N. J., intersected by tortuous channels
at head of a bay blending with the deciduous forest in the center and left.

Pl.\te XXI.

Salt marsh at Somers Point, N. J., with open channel blending with an
association, or strip of switch grass, Panicuin z'irgafum, which fronts a forest
growth of red cedar, Juuiperus I'irgijiiaua. holly, Ilex opaca, and pitch pine,
Pinus rigida.

THE COST OF LIVING IN THE TWELFTH CENTURY.

By DANA C. MUNRO.

(Read April so, 19 ii.)

As yet it is impossible to make any statement of the average cost
of living in the twelfth century in any country of Europe. Much
material is accessible in the Pipe Rolls and similar accounts, in the
charters and other legal documents, of which so many thousands
have been preserved ; but no one has attempted a careful statistical
study for this period. Thorold Rogers began his work on the prices
in England with the year 1259; Curschmann collected some items
for Germany during the years 1 190-1225 ; Lamprecht gathered some
data on prices for France in the eleventh century ; and there are
some other partial statements. Whether it will be possible to make
an accurate estimate can only be ascertained after minute and ex-
tended examination of the accessible material.

But it is possible to gather some examples which are illuminat-
ing. In 1 181 the former mistress of Henry II., and the mother of
Geoffrey, was receiving an annual pension of 20 marks or 13 pounds
6s. 8d. In the same year the " Archbishop of Norway," who was
then visiting in England, was allowed by the king los. a day for
the expenses of himself and suite. The same amount was allowed
in 1 180 to the Abbot of Glastonbury. Evidently los. a day was con-
sidered sufficient for the expenses of a high church official and his
attendants ; probably the pension of 20 marks, or a little over 8d.
a day, was sufficient for the expenses of a lady and her servant.
This is rendered more probable by the fact that Richard the Lion-
.hearted, when he hired vessels for his crusade, had to pay only 2d.
a day to sailors and 4d. a day to the captains. In 1201 the French
ambassadors made a treaty with Venice, by which the latter agreed
to carrv the crusaders across the sea and furnish them with pro-

497

498 MUNRO— THE COST OF LIVING [April 20,

visions for a year on the payments of 2 marks for each man and 4
marks for each horse. ^

The prices current at the time throw some hght upon the above :
in Lincohishire, in 1 181, a goose cost a penny; a sheep, 4d. ; an ox,
3s.; a farm horse, 5s.; a pig, is.; scarlet cloth, 6s. 8d. an ell; fine
green cloth, 3s.; gray, is. 8d. ; blankets, 3s. an ell. Thus, if Geof-
frey's mother had expended her pension in buying live stock, she
could have bought 25 horses, 25 oxen, 25 pigs, 25 sheep, and 100
geese; or if she had preferred, she could have bought 50 yards of
scarlet cloth, say, enough for four or five dresses in the fashion of
the day. The difiference in cost between the necessities and the luxu-
ries is very noticeable.

While it is impossible to state the exact cost of living, it is certain
that this cost was increasing rapidly for the upper classes, and prob-
ably for the middle classes. The rise was due to a variety of causes,
and it would be easy to make out a long list, including war, famine
and pestilence ; but two appear to have been especially important.
First, there was a change in the standard of living. Acquaintance
with the east through the crusades led to a desire for the luxuries
which were produced at Constantinople and in Asia. Before the
first expeditions to the Holy Land spices had been used only to a
slight extent in the west of Europe. At the capture of Caesarea, in
iioi, the Genoese received over 16,000 pounds of pepper as a por-
tion of their booty. This, and other spices, soon came into general
use and were imported into western Europe in great quantities. The
references in the literature of the day point conclusively to the wide-
spread use of spices and their great popularity.

The costly fabrics of the East were also in great demand, and
the heroines of the poems are frequently described as clad in the
stufifs made in Constantinople, or farther eastward. No lady was
considered well-dressed by the poet unless she had garments im-
ported from the East. Oriental rugs became so fashionable that a
manufactory for them was established in Paris. Glassware, sugar,.

' De Wailly estimates a mark as equivalent to 52 francs at the present

day ; that is, two marks would be equivalent, roughly, to 104 francs, or $20.

Of course this is entirely misleading, as it would be impossible to furnish
transportation and food for a year for $20 per individual.

I9II.] IN THE TWELFTH CENTURY. 499

dye-stuffs, and other oriental products were coveted and secured as
far as possible.

Life as a whole became more luxurious. In Germany four meals
a day supplanted the three of an earlier period ; and the ideal hero
was a mighty trencher-man. According to the Pseudo-Turpin,
Charles the Great ate " a whole quarter of a lamb, two fowls, a
goose, or a large portion of pork ; a peacock, a crane, or a whole
hare" at a meal. Luxury in dress, at least among the middle classes,
was not confined wholly to the oriental products. Fashion began its
despotic sway for Germany and other parts of western Europe in
the twelfth century, and those who could not afford the Byzantine
stuffs might in their domestic weaves imitate the prevailing styles
of long trains and full sleeves almost sweeping the ground. Shoes
for both men and women changed in style almost every year ; some-
times the toes were long and pointed, extending up toward the
knees ; at other times, short and broad. Other items of extrava-
gance might be mentioned, such as the enormous head-dresses, wigs
and other false hair ; but enough has been indicated.

Another great source of expenditure was building. The mon-
archs spent large sums on their castles and residence halls, and the
nobles and citizens followed their lead. Palaces, cathedrals, for-
tresses, country houses, town halls, hospitals and other edifices were
going up in all the leading centers. The cost of building was greatly
increased by the general substitution of stone for wood, and by the
frequent use of lead for the roofs. Great cjuantities of this metal
were exported from England to various places in France, and even
to other parts of Europe.

The second cause of the rise in the cost of living was the increase
in the amount of money available. Western Europe was just chang-
ing from Natural- to Gcldzcirfschaff. The author of the " Dialogus
de Scaccario," who wrote about the beginning of the last quarter
of the twelfth century, says that he had been told of the former
custom by which all payments to the treasury were made in kind,
and that he had seen a man who had witnessed the bringing in of
the provisions from the various parts of the country. In fact, in
the reign of Henry I. of England the sheriff's obtained their receipts

500 MUNRO— THE COST OF LIVING [April 20,

for so many fowls, eggs, ducks, hogs, oxen, etc., or so much beer,
wool, corn or other grain. But this practice had not wholly gone
out under Henry II., in spite of the statement of the author of the'
" Dialogus." In the Pipe Roll of 1181-82, for instance, there is the
record of the payment by Cheshire of forty cows in addition to their
money dues. On the whole, however, all through western Europe
payments in money were superseding payments in kind, and this was
due mainly to the increase in the amount of the circulating medium.

Large numbers of coins were brought home from the East. In
the Scandinavian lands it is said that more than 25,000 Arabic coins
have been dug up in recent times. In the literature of the twelfth
century, Arabian gold is very frequently referred to and is contrasted
with the lighter-colored gold of the West. At the capture of Csesa-
rea in iioi (when the pepper was obtained) the Genoese secured
over 400,000 solidi of Poitou, and they received only one third of
the booty. The crusaders were always keen for gold. Whenever
they won a victory they sought anxiously for the precious metals ;
frequently they cut open the bodies of the slain enemies, because
they believed the latter had swallowed their coins ; sometimes they
made great heaps of the bodies and burned them in order to obtain
the gold which had been secreted. Many similar facts might be
cited which would illustrate the enrichment of the West by the coins
brought in from the East.

Far more important, probably, was the coinage and use of the
precious metals which had previously been hoarded, especially in
ornaments and works of art. Until about the close of the eleventh
century, there had been comparatively little occasion for a large
stock of ready money, but when the crusaders made their prepara-
tions for their long expeditions they needed large sums of money,
both for their equipment and for their journey. Even the partici-
l)ants in the so-called Peasants' Crusade took enough luoney with
them to ])ay all the expenses for several months, when they marched
under the leadership of Walter the Penniless and Peter the Hermit.
Because of the demand for coins, the mints of the West were very
active in the twelfth century, lender Henry I. of England. 94
minters were busy. In 1125 all the <J4 were called up for ])unish-

19"] IN THE TWELFTH CENTURY. 501

ment on the ground that they had dehased the coinage, and each one
had his right hand struck off. Under Henry II. there was a great
amount of coining, of which the details may be followed in the Pipe
Rolls, as far as they are accessible. In addition, instruments of
credit came into use, especially bills of exchange, which greatly in-
creased the amount of capital. The Templars in their house at Paris
received deposits, and gave orders upon their house in Jerusalem.
In doing this, they were probably imitating the example of the Jews,
who had long used such papers ; and we find the example of the
Templars, or of the Jews, imitated by others, so that, e. g., by 1188
bills of exchange had become very common in Hamburg.

The extravagance of the age is well depicted in the literature.
The knightly hero is always lavish in his gifts and entertainments,
as well as in his attire. Sumptuous banquets, where the boards lit-
erally groaned under the weight of the dishes, were the fashion.
Large stone castles were built and richly adorned, and in these the
number of attendants increased greatly. The armor became more
costly ; the legal expenses, from which the nobles were never free,
mounted up ; but the main source of out-go was the necessity of
keeping up the style of living demanded by the fashion of the day.
Consequentlv the knight had to spend much more, and the minstrels
sang only of those who were generous. Even the fathers and
mothers in their advice urged their sons to give freely and never to
be niggardly.

There were great opportunities to acquire wealth. One of the
men who improved his chances to the best advantage was Suger.
He was of peasant stock and was educated at the Monastery of St.
Denis, where he became intimate with the prince who later was
known as Louis \ I. of France. The intimacy always continued, and
after the death of Louis \l., Suger, who was then Abbot of St.
Denis, acted as regent of France during the absence of Louis \TI.
on the crusade. During the time of the king's expedition, Suger
paid all the expenses of the kingdom of France out of his own for-
tune. He had previously restored and beautified the church of St.
Denis at his own expense. And he still had enough wealth, so that
in the last year of his life he planned to equip and finance a crusade

502 MUNRO— THE COST OF LIVING [April 20.

wholly from his own money. Suger was able to acquire this enor-
mous fortune because of his great ability, and because he understood
the economic conditions of the time.

The average noble had no genius for acquiring wealth, and his
feudal income, which was fixed mainly by custom, appears to have
been stationary or even declining. With the establishment of better
order and the increase of the royal power, the nobles had lost both
their opportunity to plunder and the right of private coinage, which
greatly lessened their income. ( )ne feature of the Pipe Roll for
1181-1182 is very significant in this connection. About 300 debtors
to the king were listed from various parts of England, most of
whom had disappeared or were destitute of means, so that these
debts could not be collected. Apparently most of the individuals
came from the lesser nobility. The only resource for men of this
class was to borrow at usury. The usurers formed one of the two
classes of wrong-doers against whom the preaching of the twelfth
century was especially directed. They were evidently very numer-
ous, and they preyed chiefly upon the nobles. The merchants and
the peasants seldom had to resort to the usurers. There were many
Christians engaged in this business, but more Jews, and the latter
were to suft'er severely as the result of the economic conditions.
The rate of interest in England when the security was good was 2d.
on the pound each week, compounded once in six weeks, or about
52 per cent, a year.- Consequently if a knight borrowed 40 pounds,
a sum frequently in excess of the animal income of a knight, and
was unable to pay the interest, in a year he would owe 60 pounds
and i6s. ; in two years, over 92 pounds; in three years, over 140
pounds ; in five years, over 324 pounds, and the interest then would
be over 3 pounds a week. Probably the ill-feeling against the Jews
was due very largely to the anger of the borrowers who found them-
selves hopelessly involved in debt. There is a very decided change
in the attitude toward the Jews in the twelfth centurw and it is sig-
nificant that the preparations for the crusades, when ready money
was especially needed, were so frequently accompanied by a perse-
cution of the Jews; c. g., in 1096, in 1147, in 1189. Their great

" .^hlcl^ more was demanded when tlie secnritv was not sood.

191 1-] IX THE TWELFTH CENTURY. 503

wealth is shown by the fact that the Jews of England contributed
60,000 pounds towards the crusade of Henry II., and all others only
70,000. There is no estimate of the number who contributed this
60,000 pounds, but there had been a great increase since the begin-
ning of the reign of Henry II. At that time all Jews who died in
England had to be buried in the cemetery near London. At the end
of Henry II. 's reign almost every great town had a Jewish cemetery
in the suburbs.

The peasants both in town and country gained in prosperity
during the twelfth century. The agricultural laborers profited by
the opening of more markets for their products. They were some-
times able to hire the demesne land and even to rent the mill or the
whole manor, because the lord of the manor was in need of ready
money. In France many I'illciicHZ'Cs were established which ottered
special privileges in order to attract tenants. Suger's example in
emancipating his serfs was followed more and more frecjuently by
the kings and by the lords. In England many individuals escaped
to the towns, and if they were able to remain there unmolested for a
year and a day, they were free from all possibility of pursuit.

The merchants in the towns profited most. The Lombard cities
of Italy gained great wealth by the carrying both of crusaders and
of wares. The trade extended widely in western Europe. Fairs
were established where the commodities of the whole known world
were ofifered for sale by the merchants from the various countries,
who travelled about from place to place. The increase in the dues
which the lords received from these fairs bears witness to their
prosperity and to the enlarged trade, of which they were the scene.

Gross states that the gild merchant first appeared in England
about 1 100, and that the craft society first appeared on the continent,
as in England, early in the twelfth century. If we connect these
statements with Ashley's dictum. " Trade, as an independent occu-
pation, grew up first in the service of luxury." the importance of the
change in the standard of living will be apparent. The establish-
ment of uniform weights and measures, and the universality of
certain standards of money, such as the Cologne mark, the A'enetian
ducat, or the bezant also indicate the rapid advance in commerce.

504 MUXRO— THE COST OF LIVING

The fabliaux, or " laughable stories told in verse," the especial
literature of the merchant class, began about the middle of the
twelfth century. In these tales class-consciousness is very evident.
Thev ridiculed the knights and the clergy, while always depicting
the latter as wealthy. Some of these fabliaux, which were written
for the merchants of the twelfth century, sound curiously modern,
as if they might have been told in the nineteenth century in our own
western states. They are frequently irreverent, and show an inde-
pendence of thought which is very noteworthy in this early period.
Their attitude toward women is entirely at variance with that of
the courtly literature of the age. In fact, the merchants were think-
ing for themselves, and were no longer willing to be subservient to
the nobility and the clerg}-. They were rapidly becoming important
political factors, and were winning recognition from the monarchs.
They were vying in comfort and luxury with the nobles, and fre-
quently ineffective sumptuary laws were enacted to restrict these
nouvcaux riches.

As yet too little attention has been paid to this change in the
standard of living and its eft'ects. In this paper an attempt has been
made to set forth only a few of the facts, merely to indicate the
nature and importance of the problem. Every one of the subjects
here discussed is susceptible of elaboration, and needs to be worked
out in detail for each country of western Europe and each period in
the twelfth century. The material is voluminous : as indicated
above, the legal documents should be utilized for the definite state-
ments which they contain, and the literature of the age should be
laid under contribution for its information as to the character, cus-
toms and points of view of the various classes. The chronicles un-
fortunately will furnish comparatively little, because they generally
give only the unusual events ; statements about prices drawn from
them are frequently of little value, because the figures are given on
account of their extreme highness or lowness. This field, as a whole,
oft'ers a good op|)ortunity for many monographs, and such work is
essential before we can understand the economic history of the
century which was most important in the advance of western Europe.

U.M\KRsnv OK Wisconsin^
Madison. Wis.

AN ANXIEXT PROTEST AGAINST THE CURSE ON EVE.

Bv PAUL HAUPT.
(,Rcad April 3j, igii.)

In the Biblical Legend of the Fall of ^Man, which symbolizes the
first connubial intercourse,^ the Lord pronounces a curse on Eve,
saying, I will greatly multiply thy sorrow and thy sighing;- in pain
thou wilt bear children ; nevertheless thy desire is' to thy husband
and he will rule over thee (Genesis, iii., i6).*

The great pessimistic philosopher Arthur Schopenhauer says
that the story of the Fall of Man contains the only metaphysical
truth found in the Old Testament; it is the acme of Judaism, dcr
Glanzpunkt des Judcntums; but it is an hors d' criivrc: the pessi-
mistic tendency of this legend has no echo in the Old Testament
which, on the whole, is optimistic, whereas the New Dispensation is
pessimistic, at least so far as this world is concerned."

We all know what the forbidden fruif' in the midst of the
Garden" of Eden® means: he who eats of it loses his childlike inno-
cence; his eyes are opened, just as Adam and Eve perceived that
they were naked. Not to know good and evil, that is, what is
wholesome and injurious, means to be like a child.'' In the eight-
eenth book of the Odyssey (v. 228) Telemachus says to his mother
Penelope, I am intelligent and know good and evil,^" I am no longer
a child. ^^ In the Bible this phrase is used also of the second child-
hood : Barzillai of Gilead answered David, when the king asked him
to follow him to Jerusalem, I am this day fourscore years old and
can no longer discern between good and evil, that is, my intellect is
impaired by old age, I have become again like a child.

The explanation of the Fall of Man as the first connubial inter-
course was given by the celebrated English philosopher Thom.\s
HoBBES in his Leviathan (London, 1651) and it may be traced back
to Clemext of Alexandria in the second century of our era.^- But
older than this philosophical explanation of original sin^^ is an

PROC. AMER. PHIL. SOC, L. 20I HH, PRI.NTED SEPT. 6, I9II.

505

506 HAUPT— AN ANCIENT PROTEST [April 22,

ancient protest against the curse on Eve, which we find in the fol-
lowing chapter of the Book of Genesis, containing the legend of
Cain and Abel.

The story of Cain and Abel is an institutional legend.^* Just as
the narrative of Jacob's wrestling at Peniel (Genesis, xxxii., 24-32)
explains why the Jews do not eat the great sciatic nerve, so the story
of Cain and Abel shows why the Cainites, or Kenites,^^ had the
mark of Cain,'^'^' that is, a tattooed tribal mark which warned every
man not to slay a member of that tribe. The murder of a Kenite was
avenged sevenfold: if a Kenite was killed, the Kenites would slay
seven fellow-tribesmen of the slayer. The tribe of Lamech avenged
even the slightest scratch by the death of a youth of the tribe to
which the assailant belonged. Lamech and Cain represent tribes,
not individuals.^'^ The Lamechites guarded their tribal honor even
more jealously than did the Kenites: if a Kenite was slain, seven
fellow-tribesmen of the slayer were slain to avenge his blood ; a
Lamechite, however, was not avenged sevenfold, but seventy-seven-
fold ; even a wound inflicted on a Lamechite was punished by the
death of a fellow-tribesman of the assailant, and a boy of the hostile
tribe had to pay with his life for the slightest scratch received by a
Lamechite. Therefore an ancient tribal poet addressed the women
of Lamech :

O Adah and Zillah, attend to my voice !

Ye wives of Lamech, give ear to my utterance :

A man, if they hurt us, we slay; a boy, if they scratch us, we kill;

If sevenfold Cain be avenged, then seventy-sevenfold, Lamech!"

The Kenites were a nomadic tribe in the desert south of Judah.^^
They came to Canaan with the men of Judah from the Palm City,
that is, the port of Elath,-° at the northeastern end of the Red Sea.
Moses' father-in-law is said to have been a Kenite.-^ The Kenites
were worshipers of Jhvh,-- but their oft'erings were dififerent from
the sacrifices of the sheepmen of Judah,-'' represented in the story
of Cain and xA.bel by Abe!, that is Jicrdsiiiaii, herder.-*' Cain brought
to Jhvh ofiferings of the fruit of the ground, but Abel brought of
the firstlings of his flock and of the fat thereof ; and Abel's sacrifice
was more acceptable to Jhvh than Cain's bloodless ofifering. The

191 1.] AGAINST THE CURSE ON EVE. 507

Kenites may have been a semi-agricultural tribe settled near Elath-^
before they emigrated with the Edomite ancestors of the Jews to
Canaan. Afterwards there may have been some religious differ-
ences : the Kenites clung to their vegetable oft'erings,-*' whereas the
men of Judah-" sacrificed lambs. This led to an expulsion of the
Kenites from the region of Judah.

The introductory verse, connecting Cain and Abel with Adam
and Eve, is a subsequent addition. The name Cain is explained
there (Genesis, iv., i) as being connected with the verb qaiidh, to
produce.^'^ When Eve bare Cain, she said, I have produced a man
as well as Jhvh :-'' just as Jh\h fashioned me from the rib He
took from Adam, so I have produced now a new human being. —
Some people think that, when the Lord created Eve, He did not take
a rib from Adam, but his backbone. ]\Iost of us have all our ribs.
At any rate, woman is not a side-issue.

The story of Cain and Abel was originally simply : Abel was a
keeper of sheep, and Cain a tiller of the ground. Cain offered
vegetable oft'erings to Jhvh, whereas Abel sacrificed the firstlings of
his flock. Abel's sacrifices were more acceptable to Jhvh. This
displeased Cain, and Cain said to Abel, Let us go into the field;'-*
and when they were in the field, Cain rose up against his brother
Abel, and slew him.

The field was a tribal battle-ground where the Cainites smote the
Abelites, but afterwards they were overpowered and expelled from
the territory of the sheepmen of Judah."''

A later theologian has inserted two verses (Genesis, iv., 6, 7)
which are translated in the Authorized Version as follows : And the
Lord said unto Cain, Why art thou wroth ? and why is thy counten-
ance fallen? If thou doest well, shalt thou not be accepted? and
if thou doest not well, sin lieth at the door. And unto thcc shall be
his desire, and thou shalt rule over him. There is no connection
between this last clause and the preceding one, and the translation
sin lieth at the door is impossible.

The Ancient Aversions show that the text of this theological in-
terpolation was corrupt at an early period, and the rendering given
in the Greek Bible echoes the tradition that the feud between Cain;

508 HAUPT— AN ANCIENT PROTEST [April 22,

and Abel was due to some ritual differences. The Septuagint ren-
ders: Is it not so? If thou offerest rightly, but doest not cut in
pieces rightly, thou hast sinned ? Be still ! — The Syriac Bible has :
Behold, if thou doest well, thou receivest ; and if thou doest not
well, at the door sin croucheth. — We find the same rendering in the
\^ulgate : Nonne si bene egeris, recipies; sin autcm male, statini in
foribus peccatuni aderit. — The Targum paraphrases: If thou doest
thy work well, thou wilt be pardoned ; but if thou doest not thy work
well, for the day of judgment the sin is laid up, ready to take
vengeance upon thee, if thou doest not repent; but if thou repentest,
thou shalt be forgiven."^ — All these explanations are untenable.

The original text seems to have been: If thou art good, I shall
receive thee graciously; but if thou art a sinner,^- I shall not accept
thy offering.^^ The final clause, And tinto thee shall be his desire,
and thou shalt rule over him, has no connection with the preceding
theological interpolation, but is a gloss protesting against the state-
ment in the preceding chapter: Thy desire shall be to thy husband,
and he shall rule over thec.^^ Genesis, iii., 16, states: Unto the
woman He said, I will greatly multiply thy sorrow and thy sigh-
ing ;2 in pain thou wilt bear children; nevertheless thy desire is^ to
thy husband, and he will rule over thee.

Some one — possibly a woman. ^^ or a man under the influence of
a woman, a species of the genus Homo, which is common — added to
this statement in the margin: His desire is unto thee, and thou zvilt
rule over him.^^ The story of the Fall of Man and the legend of
Cain and Abel may have been written in two parallel columns.^'
The glossator, who added the theological interpolation in the legend
of Cain and Abel, and the author of the polemical gloss to Genesis,
iii., 16 may have written their remarks in the space between the two
columns. Afterwards these two marginal glosses crept into the
text, the " sufifragettic " gloss to Genesis, iii., 16 being appended to
the theological interpolation after Genesis, iv., 5.

The word desire or longing is used also in the Biblical love-
songs, commonly known as the Song of Solomon, where the maiden
says of her lover :

My dear one's am I ; he is mine, too ; for my love he is longing. **

191 1.] AGAINST THE CURSE OX EVE. 509

The corresponding word in Arabic (sJiauq) means passionate love.
If man eats his bread in the sweat of his face till he returneth unto
the ground, and if women bring forth children born to suffer, it is
due to the forbidden fruit. Schiller says,^** the fabric of the world
is held together by hunger and by love.**'

Notes.

^ See my paper Some Difficult Passages in the Cuneiform Ac-
count of the Deluge in the Journal of the American Oriental So-
ciety, vol. xxxi., fifth page of the article, 1. 2. Cf. below, n. 13.

- Instead of heronck, thy conception, or thy pregnancy, we must
read hagigek, thy sighing; cf. Psalms, v., 2; xxxix., 4. The Greek
Bible has rbv crrevay fiov gov. Hegyonek would have a dift'erent
meaning, and ycgonck or c^aratek could not have been corrupted to
heronck.

^ Not shall he or zinll he; see my remarks in the Journal of the
American Oriental Society, vol. xxv., p. 71, n. i; vol. xxxi., fourth
page, below, of the article cited in n. i. The last two clauses may
represent an observation of the narrator ; cf. below, n. 36.

* The preceding verse, the so-called protevangelium or proto-
gospcl, should be rendered : / 1^111 put enmity heturen thee and the
zcoman. and hetzceen thy seed and her seed; it (that is, her seed, the
human race) zinll crush (lit. tread down, tread under foot, Assyr.
scpu) thy head, and thou zcilt snap at its heel. There will be per-
petual warfare between snakes and the human race ; all human
beings loathe snakes. The Messianic interpretation of this passage
is unwarranted. See my Note on the Protevangelium in the Johns
Hopkins University Circulars, No. 106 (June, 1893), p. 107: cf. my
remarks in the Xachrichtcn of the Royal Society of Gottingen,
April 25, 1883, p. 102; also Guxkel, Genesis (1910), p. 20.

^ See my remarks in the Journal of Bihlical Literature, vol. xxi.,
p. 55, 1. 8; p. 66, n. 21; Haupt, Bihlische LiehesUeder (Leipzig,
1907), p. 66.

*= \\q use this term now especially of illicit love. In Ceylon the
fruit of Ervatamia dichotoma is called forhidden fruit or Eve's
apple. The forbidden fruit in the legend of the Fall of Man is, it

510 HAUPT— AN ANCIENT PROTEST [April 22,

may be supposed, the orange-colored berry of the mandrake which
is still regarded as an aphrodisiac and supposed to promote concep-
tion; see my paper on Jonah's Whale in vol. xlvi. of these Proceed-
ings (Philadelphia, 1907), p. 152, n. 4. In Genesis, xxx., 14, the
mandrakes are called in Hebrew: duda'hn, that is, love-apples. The
fruit of the mandrake is quite round and of the size of a large plum ;
it resembles a small tomato. The largest berries have a diameter of
ilA in. (nearly 4 cm.). The idea that the forbidden fruit was a
fruit from which an intoxicating drink was prepared is untenable ;
contrast Cheyne's article in the eleventh edition of the Encyclopcvdia
Britannica, vol. i., p. 168". In the article on mandrake, vol. xvii.,
p. 566% there are five misprints in the five letters of the Heb.
word duda'hn; similarly there are two misprints in the three letters
of the Arabic name for Egypt, vol. ix., p. 41''. The new edition is
marred by a great many misprints and inaccuracies, not only in
Oriental words, but also in the English text.

■^ Garden is often used for pudendum niulieris; see Haupt, The
Book of Micah (Chicago, 1910), p. 62, n. 9.

®Eden means pleasure, delight; Heb. gan-'edn denotes a pleasure-
ground. Damascus, the earthly paradise of the Arabs, is called in
Amos, i., 5: Bct-'edn, House of Pleasure; see my remarks in
Peiser's OricntaUstische Literatur.zeitung, June, 1907, col. 306.
The Greek Bible has for Heb. ga>i-'edn in Genesis, iii., 23, 24:
o TrapaSeio-o^; tt}? Tpv<f)}]<; ; the \'ulgate : paradisns voluptatis. The
reading a garden in Eden in Genesis, ii., 8 seems to be a subsequent
modification introduced by some one who connected Heb. 'edn with
the Babylonian edinn^^SnmQr'mn edin, desert; he may have re-
garded Paradise as an oasis in the desert like Damascus ; cf.
Pinches' note in the Proceedings of the Society of Biblical Archce-
ology, London, June 14, 191 1, p. 161. Damascus means settlement
in a zi'dl-zvatered region; the original form of the name was Ddr-
masql; see my remarks in the American Journal of Semitic Lan-
guages, vol. xxvi., p. 26.

'* See Deuteronomy, i., 39; Isaiah, vii., 16; cf. the translation of
Isaiah, in the Polychrome Bible, p. ii, 1. 25; p. 141, n. 16.

" To know good and evil has about the same meaning as our
phrase to cut one's eye-teeth.

I9II.] AGAINST THE CURSE ON EVE. 511

^^ See my paper on ^lidian and Sinai in the Zcitschrift dcr
Deutschen Morgenldndischcn GcseUschaft, vol. Ixiii., p. 519, 1. 25.

^- Compare above, note 5.

^" The serpent symbohzes carnal desire, sexual appetite, con-
cupiscence. This is the original sin which has been transmitted to
all descendants of Adam ; only the innocents are free from it.
Coleridge {Aids to Reflexion, 1825) held that Adam's fall was a
typical experience repeated afresh in every son of Adam. Mutato
iwiitiiie. de te fabiila Harra/ar; see Hastings' Dictionary of the Bible.
vol. i., p. 842". In the well known Assyrian relief from Nimriid,
representing the fight with the dragon, the penis of the monster is
a serpent; see the plate in Geo. Smith, The Chaldean Account of
Genesis, edited by Sayce (London, 1880). The serpent in the story
of the Fall of Man is a later addition ; in the original form of the
legend Eve was the sole seductress; Eve means serpent (Heb.
Hazvzi'dh^ Aram, hiz^'ya, snake. Arab, hdyyah). See n. 29 to my
paper cited above, n. i.

^*This legend explains the institution of tattooed tribal marks
and the institution of blood-revenge (cf. nn. 15 and 17). It illus-
trates also the superiority of nomadic animal sacrifices compared
with agricultural bloodless offerings (cf. n. 26).

^■' Kenite means descendant of Kain or Cain; Cain is the eponym
ancestor of the Kenites.

^° See Genesis, iv., 15; cf. Haupt, The Book of Canticles, p. 41 ;
Biblischc Liebeslieder, p. 61.

^' Cf. our Uncle Sam. John Bull, Columbia, Germania, &c. A
Bedouin tribe Cain (Qain) dwelt in the desert of Sinai and the
neighboring districts about six centuries after Christ ; see Xoldeke's
article on Amalek in the Eucyclopccdia Biblica, col. 130.

^^See Genesis, iv., 23, 24; cf. my paper on Closes' Song of
Triumph in the American Journal of Semitic Languages, vol. xx.,
p. 164.

^^Cf. I Samuel, xxvii., 10. The Kenites lived with the Amale-
kites, but they were on friendly terms with the men of Judah,
whereas the Amalekites were perpetually at feud with the Judahites,
cf. I Samuel, xv., 6 and Judges, i., 16 (see below, n. 21). In the

512 HAUPT— AN ANCIENT PROTEST [April 22,

Book of Esther, Haman is called an Agagite, that is, a descendant
of Agag, the king of the Amalekites, who had been spared by Saul,
but was hewn in pieces before Jiivii by Samuel, whereas ]\Iordecai
is introduced as a descendant of the first king of Israel; see Haupt,
Piirim (Leipzig, 1906), p. 12, 1. 30. The Amalekites were Edomites
who had invaded southern Palestine before the Edomite ancestors
of the Jews, after their exodus from Egypt, conquered the region
afterwards known as Judah (see n. 23). In Numbers, xxiv., 20
Amalek is called the first (that is, oldest) of the nations. The
Amalekites, however, had intermarried with other (non-Edomite)
tribes; in Genesis, xxxvi., 12, therefore, Amalek is introduced as a
son of Esau's first-born, Eliphaz, by a concubine, just as the sons
of Jacob's concubines, Bilhah and Zilpah, were tribes with foreign
elements; see my paper on Leah and Rachel in the Zcitschrift fi'ir
die ahtestamcntUche WissciiscJiaft, vol. xxix., p. 285. The identi-
fication of Amalek with the cuneiform Meluha (OriciitaHstische
Literaturscitiing, June, 1909) is untenable. According to i Chron-
icles, ii., 55, the Rechabites {cf. Jeremiah, xxxv. ; 2 Kings, x., 15,
22,) were descendants of the Kenites; but this can hardly be correct.
The Rechabites resembled the ancient Kenites in that they were
ardent worshipers of Jhvii, and that they continued to live in
tents after the men of Judah (see n. 23) had settled in Canaan.

-°See p. 360 of my paper on The Burning Bush and The
Origin of Judaism in vol. xlviii. (No. 193) of these Proceedings
(Philadelphia, 1909) and my paper on Midian and Sinai (cited
above, n. 11), p. 506, 1. 12; p. 512, 11. 15 and 33; p. 513. 1. 2. In
Genesis, iv., 17 we read that Cain built a city.

-^ In Judges, iv., 11 the words tnib-beiie hohdb Moseh are a
secondary gloss (or variant) to niiq-Ooiii, and hotcn is a tertiary
gloss to hobdb. The original text of Judges, i., 16 s^ems to have
been: zcc-Oaiii 'aldh uie-'ir hat-tcinarhii ct-Yehuddli inidbdr 'Ardd
icai-yelck zcai-ycseb et-'Amalcq, Cain went up with Judah from the
Palm City to the wilderness of Arad, and went and lived with
Amalek. The words bene . . . hot en Moseli and YchuddJi aser
ban-negcb are glosses. vSec the translation of Judges, in the Poly-
chrome Bible, pp. 8 and 2; also p. 49, n. 15; p. 62, 1. 55; cf. my

I9II.] AGAINST THE CURSE ON EVE. 513

paper on Hobab^ father-in-law in the Oriciitalistischc Litcratur-
ccitujig, April, 1909, col. 164.

-- For Jhvh see p. 355, n. 2 and p. 357 of my paper The
Burning Bush, cited above, n. 20.

-^Judah is the name of the worshipers of Jhvh, who were
united under the leadership of David about 1000 b. c. David was
not an Israelite, but an Edomite. See n. 18 to my paper The Aryan
Ancestry of Jesus in The Open Court, Chicago, April, 1909 ; cf. p.
358 of my paper The Burning Bush, cited above, n. 20, and my
paper on ^lidian and Sinai (see above, n. 11 ). p. 506. 1. 2; p. 507,
1. 36; also Erbt's remarks in OriciifaHstische Litei'atiirccitinig, July,
191 1, col. 298, 1. 19. For the sheepmen of Judah see p. 284, n. 5
of my paper on Leah and Rachel, cited above, n. 19 ; cf. my paper
on the five Assyrian stems la'u in the Journal of the Anicricaji
Oriental Society, vol. xxxi.

-* In Syriac, habbdltd (or hebdltd, cbdltd) means herd, drove,
especially of camels ; cf. Obil, the name of David's keeper of camels,
I Chronicles, xxvii., 30 (see Encyclopccdia Biblica, col. 6). Hebel,
the Heb. form of Abel, may be connected with hobil, to lead. The
name of Jabal, the father of such as dwell in tents and of such as
have cattle, Genesis, iv., 20, may be derived from the same root ; cf.
Hastings' Dictionary of the Bible, vol. i., p. 5*^. The original form
of Jabal seems to have been J obil; the Greek Bible has Iw/SeX (and
inBHA for IHBHA). Hebel may be a subsequent modification
of Hobil, due to a popular etymology combining the name with Heb.
hebel (for hdbil) breath, transitoriness ; see below, n. 27. For
Jdbll = Hobil cf. my remarks on Jair= Me'ir, p. 513, 1. 24 of my
paper cited above^ n. 11. The name Moses, Heb. Moseh, may have
had originally an 'A in at the end so that it would be equivalent to
Joshua ; see /. c, 1. 26. and for the vanishing of the final laryngeal,
op. cit., p. 522, 1. 47; also Haupt. The Book of Esther (Chicago,
1908), p. 74, 1. 14.

-■' Cf. p. 528, 1. 38 of my paper cited above, n. 11.

-" In Canaan a bloodless offering smacked of Canaanite heathen-
ism ; cf. the remarks on p. 44 of the translation of Judges in the
Polychrome Bible. Skixxer says on p. 106 of his new commentary

514 HAUPT— AN ANCIENT PROTEST [April 22,

on Genesis (1910) : It is quite conceivable that in the early days of
the settlement in Canaan the view was maintained among the
Hebrews that the animal offerings of their nomadic religion were
superior to the vegetable oft'erings made to the Canaanite Baals.

"" Cain may be connected with the Ethiopic taqdnya which means
to till the ground; cf. the Pachomian rules in Dillmann's Ethiopic
chrestomathy, p. 60, 1. 4. Taqdnya means also to zvorship God; cf.
Arab, qdnata (quniit) and Lat. colere. Stems tertice y and medico y
often interchange ; cf. Ethiopic qdndya, to sing, and Arab, qdinah,
songstress, Heb. qindli, elegy. For Ethiopic qent%y, servant, we
have in Arabic: qain-, plur. qiydn. In Arabic, qain means also
smith, metal-zvorker, Syr. qaindyd. Some scholars, therefore, be-
lieve that the Kenites were a tribe of wandering smiths. Sayce
says (in Hastings' Dietionary of the Bible, vol. ii., p. 834'') that the
Kenites resembled the gipsies of modern Europe as well as tne
traveling tinkers or blacksmiths of the ^Middle Ages. Skinxer
states (on p. 113 of his commentary on Genesis) that there are some
low-caste tribes among the Arabs, who live partly by hunting, partly
by coarse smith-work and other gipsy labor in the Arab encamp-
ments ; they are forbidden to be cattle-keepers and are excluded
from intermarriage with the regular Bedouins, though on friendly
terms with them; they are the only tribes of the Arabian desert
that are free to travel where they will, ranging practically over the
whole peninsula from Syria to Yemen.

The legend of Cain and Abel may have connected the name Cain
with the allied stem qinnc, to be jealous, envious, passionate, just
as the name Abel (see n. 24) was combined with hdbl (for hdbil)
breath, transitoriness. The saying of Ecclesiastes, Vanity of vani-
ties (that is, How utterly transitory is everything!) is in Hebrew
hdbcl hdbalim; see Haupt, Koheleth (Leipzig, 1905), p. i; Ec-
clesiastes (Baltimore, 1905), p. 34, n. 2.

'* Lit. icith Jhvh. Also we use xvith in the sense of like, an-
alogously to. Shakespeare says. As if icith Circe she zvould change
my shape. Cf. the Critical Notes on the Heb. text of Genesis,
in the Polychrome Bible, p. 118. My interpretation of this diffi-
cult passage has been adopted by Cheyne, Encyclopccdia Biblica,

I9II-] AGAINST THE CURSE ON EVE. 515

col. 619, n. 3 : 7 Jiavc created a man even as Yahu'eh; but we must
not substitute Ic-'unundt. Nor can we read is ot Yalm'cli, the man
of the mark (cf. above, n. 14) of Jhvh, or u et'anKi'eh, a man
whom I desire. The prediction of the serpent that Eve and her
husband would be like God, if they ate of the forbidden fruit, im-
plied that they would be able to create new human beings, and this
would make the race of Adam immortal. Cf. the fourth page,
below, of my paper cited in n. i.

-^ This clause is preserved in the Samaritan Pentateuch and in
the Ancient Versions. The A'ulgate has Egrediaiiiur foras.

"'^Cf. my explanation of the story of Judah and Tamar in n. 26
to my paper cited above, n. 11.

"^ Cf. G. J. Spurrell, Xotcs on the Text of the Book of Genesis
(Oxford, 1896), p. 2.

"-Contrast the blood of righteous Abel in ^latt. xxiii., 35; see
also Hebrews, xi., 4; i John, iii., 12.

^' We must read: Halo, im tetib. essa pancka ; z^'c-'iin hofc atta.
Id eqqdh qorbancka. In the received text hote attd is mispointed
and misplaced : it appears as hattdt between lap-petah and robeg
which are corrupted from Id eqqdh qorbdnkd. The Greek Bible
read le-natteh instead of lap-petah, and rebdc for robee. The read-
ing of the received text, im 15 tctib, if thou doest not well, is a later
substitution for the original im hote attd, if thou art a sinner. We
might read also Id ergeh minhateka. but this could not have been
corrupted to lap-petah robcQ. In lo eqqdh qorbdnkd one of the
Alephs in Id eqqdh was omitted; q of qorbdnkd dropped out after
the final h of eqqdh. and n was omitted after the b of qorbdnkd; the
letters for ;/ and b are similar in Hebrew ; for q = h see Crit.
Xotes on Kings, in the Polychrome Bible, p. 187, 1. 20. For eqqdh
qorbdnkd cf. Psalm vi., 10: Yahzvch iqqdh tepillati, Jhvh will re-
ceive my prayer, and Assyr. teleqi tcmcqsu and leqdt unneni, &c.
(see Delitzsch's Assyr. Handzi'drterbiich, p. 384'', d). Guxkel's
reconstruction of the text (in Die Schriften des Alten Testaments
iibersetst von Gressmann, Guxkel, &c.. part 5. Gottingen, 1910,
p. 69) does not commend itself.

'* C/. Ephesians, v., 22; Colossians, iii., 18; Titus, ii., 5; i Peter,
iii.. I.

516 HAUPT— AN ANCIENT PROTEST [April 22,

^■' Like Deborah, Esther, Judith, &c.

^'^Cf. the observation of the narrator (see n. 3) in Genesis, ii.,
24: Therefore a man leaves his parents and clings to his mnfe. The
rendering shall leave (Matt., xix., 5; Mark, x., 7) is incorrect; it is
not a prophecy, nor is it an old saying dating from remote times
when the husband went to the tent of the wife and joined her clan,
although it is noteworthy that Eve, not Adam, names the child in
Genesis, iv., i (cf. above, n. 28). We may compare the line in the
Biblical love-songs (Canticles, viii., 7) where the poet says of Love:

If one should resign for it all his possessions,
could any man therefore contemn him?

This means, from the Oriental point of view: If a man should
sacrifice all his possessions to buy a beautiful girl ; see Haupt,
Biblische Lieheslieder, p. iii. Thomas Dixon, Jr., says in his
novel The Leopard's Spots of Simon Legree : They say he used to
haunt the New Orleans slave-markets when he was young and
owned his Red River farm, occasionally spending his last dollar to
buy a handsome negro girl who took his fancy.

^' Cf. the remarks in n. * * to my paper Lsaiah's Parable of the
Vineyard in the American Journal of Sonitic Languages, vol. xix.,
p. 194.

■'•■ See Haupt, The Book of Canticles, p. 5 ; Biblische Lieheslieder,
p. 4.

•'"Schiller says in the last stanza of his poem Die Weltiveisen:

Doch vveil, was ein Professor spricht,

Nicht gleich zu alien dringet,

Es iibt Natur die Mutterpflicht

Und sorgt, dass nie die Kctte bricht

Und dass der Reif nie springet.

Einstweilen, bis den Bau der Welt

Philosophic zusammenhalt,

Erhalt s:'e das Getriebe

Durch Hunger und (lurch Liebe.

"•"As a striking illustration of the manner in which some of our
leading newspapers occasionally mislead their readers, I will sub-
join here the " report " of my paper, which appeared in The Press,

I91I-] AGAINST THE CURSE ON EVE. 517

Philadelphia, April 23, 191 1, under the caption Education and Race
Suicide: " Declaring that race suicide is due to an increase in intelli-
gence, and theorizing that the human emotions become fewer as
human beings become better educated, Dr. Paul Haupt, professor
of Semitic languages at Johns Hopkins University, spoke at the
session yesterday morning. Contrary to the hope of many members
of the Society, Dr. Haupt advanced none of his religious opinions in
the course of his address. He spoke upon ' An Ancient Protest
against the Curse on Eve' and confined himself wholly to observa-
tions on race suicide." — The abstract which I had placed at the dis-
posal of the press was printed in the Philadelphia Ledger, the North
American, &c., April zt^, 191 i.

MAGELLANIC PREMIUM

Founded in 17S6 by John Hyacinth de Magellan, of London
191 I

THE AMERICAN PHILOSOPHICAL SOCIETY

Held at Philadelphia, for Promoting Useful Knowledge

ANNOUNCES THAT IN

DECEMBER, 191 1

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LATING TO NAVIGATION, ASTRONOMY, OR NATURAL PHILOSOPHY (MERH
NATURAL HISTORY ONLY EXCEPTED) UNDER THE FOLLOWING CONDITIONS :

1. The candidate shall, on or before November i, 191 1, deliver free of postage
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PROCEEDINGS

OF THE

American Philosophical Society

HELD AT PHILADELPHIA

FOR PROMOTING USEFUL KNOWLEDGE

Vol. L. October-December, 191 i. No. 202.

CONTENTS.

The Formation of Coal Beds. II. By John J. Stevenson 519

Stated Meeting, May 3, igii xtii

Stated Meeting, October 6, igir xiii

Stated Meeting, November 3, igii xiv

Stated Meeting, December i , igii xiv

Corrigendum xv

Index , xvii

PHILADELPHIA

THE AMERICAN PHILOSOPHICAL SOCIETY
104 South Fifth Street

1911

American Philosophical Society

General Meeting — April 18-20, 19 12

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PROCEEDINGS

OF THE

AMERICAN PHILOSOPHICAL SOCIETY

HELD AT PHILADELPHIA
FOR PROMOTING USEFUL KNOWLEDGE

Vol. L October-December, 1911 No. 202

THE FORMATION OF COAL BEDS. II.*

By JOHX J. STEVEXSOX.

Some Elementary Problems.

(Read November j, 191 1.) »

It is necessary, first of all, to consider some matters to which ref-
erence is made by every one who has endeavored to explain the
formation of coal beds. Too many seem to have been content with
acceptance of current statements respecting the apparently common-
place phenomena and too few have thought essential a careful study
of work done in recent years. The indefinite and often contradic-
tory assertions contained in discussions, published within the last
decade, compelled the writer to study the available literature and,
as far as possible, to make examination of the phenomena in place.
This study has led him to reject some of his cherished beliefs while
it has confirmed others. At the same time, it has increased his
respect for the problem, which he has undertaken to solve. The
topics to be considered in this portion of the work are :

The efifect of floods upon a cover of vegetation.

The phenomena of peat deposits.

The buried forests.

* Part I appeared in these Proceedings, Vol. L., pp. 1-116. •

PROC. AMER. PHIL. SOC. , L. 202 H, PRINTED NOV. 15, I9II.

519

520 STEVENSON— FORMATION OF COAL BEDS. [November 3,

Each of these topics will be considered only in its relation to the
main problem.

The Effect of Floods upon a Cover of Vegetation.

A torrent dashing through a narrow gorge is the poet's symbol
of resistless force ; a great river in flood, bearing on its surface
houses, trees and other floating materials in prodigious quantity,
seems possessed of almost illimitable power for destruction. These
conditions, so familiar to all, have led to the conception that, in the
eroding and transporting power of streams in flood, one can find
explanation for the origin not only of sandstone and other inorganic
deposits but also for that of coal and lignite beds interstratified with
them. So much importance has been assigned to this explanation
bv several authors, that the phenomena must be considered in detail.

The Work of Torrents. — The torrent in full flood is an interest-
ing spectacle but its importance in this connection is confined chiefly
to its bearing on the origin of inorganic sediments.

Long ago De Luc^ described deposits made by torrents as resem-
bling a much flattened loaf of sugar and he employed the term
" cone " to distinguish them from the talus at foot of clifl^s. When
a stream ceases the cutting down of its bed. the formation of a cone
ends and vegetation takes possession of the surface, even of steep
slopes alongside of the stream. Eventually the surface is covered
with a thin coat of soil and men settle upon it. Such a cone was
seen by De Luc on the right bank of the river Arc, en route from
Mount Cenis into Italy. It extends from Aigue-belle to Saint-Jean
de Maurienne and the line around its base is nearly three miles. It
is high against the rocky wall and the surface is comparatively steep.
Its history is the same with that of many others. The stream cuts
a channel in the cone ; occasionally, during a great flood, the banks
are overflowed, but the injury is not enough to drive away the inhabi-
tants. A fall from the walls of the gorge forms a talus against
which the stream flows; water finds its way through the sands and

' J. A. DeLuc, " Lettres physiques et morales sur I'histoire de la terre e*^
de I'honime," Vol. II., 1780, pp. 67-68.

118

I9II.] STEVEXSOX— FORMATION OF COAL BEDS 521

renders the mass almost jelly-like. A winter of heavy snows, fol-
lowed by an unusually warm spring, leads to abrupt swelling of the
water and the soft mass is swept out over the surface of the cone,
flowing like a flood of lava. Such were the conditions here. A
village, la Chapelle, had been built: in 1752, the torrent washed out
a vast mass of rock and debris, which covered everything to a depth
of 15 to 20 feet, completely burying the hamlet.

In a broad valley, the effects of the torrent's work are confined
to the cone, but conditions are dift'erent where the valley is narrow.
A few years prior to the disaster at la Chapelle, another cone was
formed in the Arc valley between Saint-Andre and Saint-Michel.
The river was dammed and a lake was the result. The inhabitants
of a drowned hamlet endeavored to make a canal through the dam,
but the great fragments foiled them and the river was left to make
its own canal. Dc Luc visited the locality several times. When he
last saw it, the river had filled the lake with debris, through which it
flowed gently, while above and below it foamed amid masses of
rock. De Luc notes with some interest that on the other side of the
valley, opposite la Chapelle, a torrent was still at work, building its
cone. Each spring saw the surface covered by a flood, bringing
down new material. Yet the trees, which had gained place and had
sent their roots down amid the rock- fragments, maintained them-
selves against the rushing waters, laden with rocks and debris, and
inhabitants of the region gathered fagots there.

Similar phenomena are familiar to all students of mountainous
areas. Dejection cones, some of them enormous, are numerous
along the Rhone from A'iege to Alartigny. The flood additions are
distinct, several of the cones being deposited by streams with fall
of more than 250 feet per mile. Except where new channels had
been cut, the trees growing on the surface of the cones are appar-
ently uninjured, though in some cases they have been bent by blocks
of rock, whose advance they had checked. The valley of the Adige
between Botzen and Rovereto presents many illustrations of similar
type ; in the mountain areas of the western L'nited States such con-
ditions are merely commonplace.

119

522 STEVENSON— FORMATION OF COAL BEDS. [November 3,

McGee's- observations in the Sonoran district of Arizona and
Mexico are equally instructive, though dealing with a somewhat dif-
ferent type of phenomena. That district is within the arid region
and the valleys are sand wastes, with shallow channel ways which
are dry during all but, perhaps, five days in each year. The moun-
tains are scarred by barrancas or stream-worn valleys, which end
abruptly at the plain. The streams during the greater part of the
vear are mere threads ; but, during thunder gusts or cloudbursts, the
old channels are filled and new ones digged, though the flow may
last but a few minutes or at the most a few hours. The stream
gathers loosened rock masses in the mountains, hurls them down
slopes into the barrancas, dashing them to fragments and carrying
the debris to the edge of the plain. There the coarser materials are
dropped, but the finer stulT is transported beyond as a sheetflood
until the water disappears by absorption or evaporation. The incli-
nation of the channel ways is not far from 300 feet per mile in the
mountains, decreases to 200 feet at the edge of the plain and to 50
feet at the end of the torrential area, several miles away. The
flooding of the plain has, in some cases, a width of ten or more miles.

McGee saw one of the floods in 1894. It came abruptly, a mass
of water thick with sand, foaming and loaded with twigs and dead
leaves. It advanced at first with " racehorse speed " but the velocity
diminished quickly owing to evaporation and the flood died out in
irregular lobes. The depth was not more than 18 inches on the
lower border, where the width of the muddy flood was about half
a mile. The noteworthy feature in this connection is that the mass
of slime, moving with so great speed, had no injurious eft'ect upon
the clumps of mesquitc bushes, scattered here and there over the
slope. When the flowing mud reached those clumps, its speed was
checked momentarily ; its course was diverted and it moved along-
side at twice to thrice the ordinary rate. After the flood was over,
the most striking observable efi^ect was the accumulation of twigs
and branches against the clumps of shrubbery and other obstacles.

Russell's notes on the Yahtse river of Alaska, to be considered

'W J McGce, "Sheetflood Erosion," Bull. Geol. Soc. America, Vol.
VIII.. i<S()7, pp. 87-112.

120

191 ■•] STEVEXSOX— FORMATION OF COAL BEDS. 523

in another connection, are equally in place here. That river, issuing
from the Malaspina glacier as a swift flood, lOO feet wide and 15
to 20 feet deep, has invaded a forest and surrounded the trees with
sands and gravel to a depth of many feet. That current, rapid
enough to carry a great load of very coarse material, was not strong
enough to uproot the trees and evidently it could not break off the
trunks until decay was well advanced. Russell's photograph shows
the conditions distinctly.

Smyth^ has described conditions in the Adirondack mountains of
New York, which are of no little importance in this connection and
they will be utilized in the sequel, as the character of the region is
very like that imagined for some limnic basins in Europe. Many
small lakes exist in that region, varying from a few rods to three
or four miles in the longer diameter. They are of post-glacial origin
and, in many cases, are surrounded by high hills of metamorphic
rock, whence streams with rapid fall flow in comparatively narrow
valleys. Big Rock lake is typical. It is a mile and a half long, three
fourths of a mile wide and is fed by streams which carry much sedi-
ment and by their deposits are changing the outline of the lake. The
new area is a level marshv meadow, about a foot above the water,
covered with a heavy growth of grass and carrying some small bal-
sams and tamaracks. The lakes show every stage from pond to
meadow and one of them has been changed throughout into meadow,
through which its stream meanders on the way to Big Rock lake, one
mile away. After heavy rains, water flows over the meadows to a
depth of a foot or more, leaving a sediment of varying thickness;
but the torrential streams feeding the lake, though flowing through
gorges, whose steep walls are more or less densely timbered, rarely
bring down trees or other vegetation.

Torrents carrying no debris do as little injury to vegetation as
to the rocks over which they flow. The writer has recognized this
many times in the Rocky and other mountain areas of the western
United States. Clear creek in Colorado, formed by the union of
streams from Gray, Torrey and other high peaks of the Front range,

^ C. H. Smyth, "Lake Filling in the Adirondack Region," Amer. Geolo-
gist. Vol. XL, 1893, pp. 85-90.

121

524 STEVENSON— FORMATION OF COAL BEDS. [November 3,

is subject to abrupt rise in the early summer, when hot days cause
rapid mehing of the snow on those peaks. The upper streams pass
over hard rocks and among huge masses which choke the channels,
so that, below the union, the creek, following a rocky, mostly narrow
gorge and with rapid fall, carries even in great flood comparatively
little sand or silt. A rise of 10 feet within 3 or 4 hours is of fre-
quent occurrence. The low narrow " bottom," though so often
overflowed by rapidly moving water, is grassy and bears some shrubs.
In some places, where the canyon widens and the stream, under ordi-
nary conditions, flows less rapidly, one finds petty islands of detritus
covered by shrubs, some of them more than 15 feet high. Clearly
these plants are torrent-proof, they have maintained their place from
birth. Similar conditions were observed on many other streams of
like character.

A Cover of Fcgctat-ioii Protects against Erosion. — Within any
given district of moderate size, some streams are turbid while others
arc limpid even in flood time. The water may be limpid or turbid
in dilTerent portions of the same stream. As the rainfall is the same
throughout there must be local causes for the variation.

The process of erosion begins with the impact of a raindrop ;
but that impact is incft'ective if the drop fall on more or less elastic
material. Thus it is that a cover of decayed vegetable matter, a
coating of hunuis, protects a slope against the erosive power of rain-
fall ; it protects existing vegetation from removal and it may enable
plants to regain hold on spaces l)are(l by fire or other agents, even
though the slope he abrupt.

Ashe* studied an area which has great variety of soils, as the
section extends from tlie Archean to the Quaternary. Soils from
partly mctaniorpltosed sandy shales or from mica schist oft'er little
resistance to erosion : in some cases they cannot nourish a sod but
each supports its own ly])e of trees. Denuded of forest, the surface
is gashed quickly 1)\ rains, but when forested it loses little. The
accunuilation of litter or lumuis within the Potomac area is small

' W. W. Ashe, " Relations of Soils and Forest Cover to Quality and
Quantitj' of Surface Water in the Potomac I'.asin,"' l'. S. Gcul. Sufvcy,
Jl'aler Supply and Irrigation Paper, 192, 1907, pp. 29<>-335.

122

191 1] STEVENSON— FORMATION OF COAL BEDS. 525

because of climatic conditions, but it suffices to protect these soils
on all except the steepest slopes. Limestone soils, occupying much
of the area, are very apt to " wash " when under cultivation, but
where covered with forest even the steepest slopes retain their cover
of humus and the run-off water is never turbid. Sandstone soils
vary much in resistance, when bared, but where they are protected
by a thin cover of humus the waste is insignificant. The water of
small streams flowing from forest mountain-sheds is clear and pure.
The great resistance offered by humus is apparent from the figures
given by Ashe. Pines growing on poor soils, rarely yield more than
2 inches ; yet this protects all except the steepest slopes. Chestnut
oak and white oak give but 3 inches ; they too grow on poor soils,
which, when exposed, are torn away rapidly. Other woods give
from 5 to 6 inches of litter, which is so absorbent that for several
days after a rain one can squeeze water from it as from a sponge.
Ashe's observations show that this vegetable litter, in the semi-
decomposed condition, is so interwoven that it not only protects the
underlying soil but also itself resists removal as does a well-rooted
sod. The streams coming from the humus covered area are free
from vegetable matter, aside from occasional twigs and, at times,
some soluble matters leached from the humus.

The White mountains of New Hampshire illustrate well the
incompetence of rainfall to remove living vegetation. The rock in
that region is mostly granite and the soil, formed since the glacial
period, is very largely humus. The slopes are abrupt and the walls
of gorges frequently show more than 50 degrees ; but most of the
area below timber line has a dense cover of vegetation, largely spruce.
Yet rains have always been frequent and many times almost deluge-
like. The covering of humus is undisturbed by those rains ; even
wiiere lumbermen have cut away the forest and left their litter and
the humus exposed to the fury of storms, one finds little evidence
of removal.

Cloudbursts or extraordinary downpours of rain have occurred
many times within this area. C. H. Hitchcock has described the
flood in the Flume at Franconia, which washed away the great
boulder which had been dropped by the retreating ice and had re-

123

626 STEVENSON— FORMATION OF COAL BEDS. [November 3.

mained suspended in the Flume. That huge mass has never been
found. Yet, aside from a landsHde or two, the terrific rainfall left
the vegetation on the steep slopes unscarred. In June of 1903, a
cloudburst of unusual severity broke on the northern part of the
White mountains. The roads were gullied and rendered impassable ;
bridges, large and small, were swept away throughout the region as
the streams were filled beyond the high water mark of spring
freshets ; sheets of water poured down naked rock surfaces in many
portions of the abrupt spaces and landslides of limited extent were
produced where the slope was covered with loose material. But this
vast flood of water did practically no injury to the forest-covered
slopes; even debris left on the mountain side by tree-choppers was
almost undisturbed.^

But the most noteworthy evidence in this region is found on the
areas wdiich have been burned over. When a forest fire destroys
the soil near the top of a divide or on a very abrupt slope, the
residue is removed quickly by rain and the granite is exposed. But
if the organic matter has not been destroyed, the soil resists ordinary
rains even on steep slopes. If drenching rains be delayed for a few
weeks, the surface gains a cover of fireweed {Erechtitcs hieraci-
folia) and rain is powerless. This growth is succeeded in the fol-
lowing season by a dense cover of raspberry, fern and other plants,
among which a cherry takes root to become the characteristic form
in the third season. Birches, maples and poplars are prominent
during the next season and within five years the spruces make their
appearance. If drenching rains follow quickly after a forest fire,
the process of restoration is merely retarded, it is not prevented.

Glenn*^ studied the problem throughout the southern Appa-
lachians, an area of 400 by 150 miles, and his studies were extended
to another area farther north, 200 by 50 miles. The examination
was continued westward for a long distance down the Tennessee
river, so that the investigation embraced every type from the bold

° Communicated by C. A. Snell of Maiden, Mass., who examined the
whole area within four days after the disaster occurred.

" L. C. Glenn, " Denudation and Erosion in the Southern Appalachian
Region," U. S. Geol. Survey, Professional Paper, y2, 191 1, pp. 15-18, 23, 24,
59, 93, 96, 99.

]24

'911 J STEVEXSOX— FORMATION OF COAL BEDS. 527

mountains, cut by canyon-like gorges, to broad river valleys with
wide bottoms in which the streams meander. This study concerns
also some matters to be considered hereafter, but they are included
here for convenience of reference.

Glenn asserts that, in forested areas, erosion is at its minimum,
for the soil is protected by the litter from impact of raindrops. As
drops move down the slope, they are checked by the litter or are
absorbed by it, and the rainfall moves so slowly through the mass
that for hours after rainfall, the cover is full of water. Even such
gullies as were seen have their bottoms covered with litter and
plants, showing that the erosion, by which they have been produced,
is very slow. Streams flowing from the forested regions rise grad-
ually during heavy rains and fall to normal more gradually, because
the litter retards flow. Such streams, even when highest, are, as a
rule, but slightly discolored and that discoloration is caused in great
part by macerated fragments of leaves and decaying plants, for they
carry little mineral matter in suspension. Some of them remain
wholly clear even when swollen to far beyond their normal stage.
But removal of the forest brings about an abrupt change. The pro-
tective efficiency of even a root-matted soil is evident, for when a
tree is uprooted or a road is cut, so as to break the continuity, erosion
begins at once. The contrast between forested and denuded areas
is so striking that no argument is needed. Grass-covered slopes may
be destroyed by breaks made when a cow crosses them after pro-
longed rainfall, but erosion can be checked by covering the surface
with litter, held in place by brush ; weeds and bushes spring up
quickly. The writer adds his testimony in confirmation of these
observations by Glenn, for he has seen many thousands of acres of
cleared land, which had been abandoned after a few years of culti-
vation and which now are covered by a dense growth of hard wood —
and this on the steep slopes of the Mrginian Appalachians.

Glenn's volume is a commentary on the protective influence of
vegetation and on its resistance to erosion. The changes in the rivers
since the removal of forests from their headwaters, the increased
erosion, the increased destructiveness of floods owing to the greate*-
load of inorganic matter are set forth clearly on almost every page.

125

528 STEVENSON— FORMATION OF COAL BEDS. [November 3,

This increased load has led the formerly almost limpid streams to
aggrade their lower reaches, to convert once fertile bottoms into
marshes or to cover them with sand and gravel. This aggrading, in
many instances, forced the streams to cut new channels or a network
of channels through the plain. But this lateral cutting is prevented now
by planting willows, aspens, balm of Gilead and other rapidly-growing
plants on the river banks down to the water's edge. The silt-laden
flood does little injury to these plants and the plain itself is injured
only by drowning of crops when floods come in the growing season.
Glenn contrasts conditions in the Coosa and Chattahoochee basins.
The former river rises in an area still forested and its waters in
flood carry little inorganic matter to cause destruction ; but forests
have been removed from the headwaters of the latter, floods are more
frequent and the accumulation of sand is very great — a condition
wholly unknown one hundred years ago.

Rixon' gives similar testimony to the ability of humus to protect
itself as well as underlying material from erosion. " The litter and
underbrush among the alpine timber arc very heavy, having accu-
mulated for ages. One class of timber, having reached maturity,
decays, dies and falls, only to be supplanted by another growth,
which in time follows its predecessor." This is in a region where
rainfalls are infrequent but extremely violent.

Tuomey^ studied the influence of forests on surface run-off.
His observations were made on four small catchment areas in south-
ern California, where wet and dry seasons are well-marked. In
December, iSqq, the rainfall was 18 inches. This was at the close
of the long dry season, when litter and soil alike were desiccated
and each absorbed a large part of the rainfall. The percentage of
run-ofl^ is given in the first column :

35
33
43
95

' T. F. Rixon, " Forest Conditions in the Gila River Forest Reserva-
tion," U. S. Geol. Survey, Prof. Paper, 39, 1905, p. 18.

' J. W. Tuomey, " The Relation of Forests to Stream Flow," Year Book
of U. S. Dep't of Agriculture, 1903, pp. 279-288.

12(>

I.

Forested

3

2.

Forested

6

3-

Forested

6

4-

Non-forested

40

1911.] STEVENSON— FORMATION OF COAL BEDS. 529

But ill January, February and IMarch, when the absorbed moisture
in the htter was great, the contrast still remained, as appears from
the second column, where the run-off from the forested areas aver-
ages only three eighths while that from the non-forested area was
nineteen twentieths.

The great dunes of Bermuda have their advance checked by vege-
tation. A network of vines creeps over the surface and breaks the
force of the wind. Clumps of grass take root in the open spaces
and, within a brief period, the heavy rains can do little more than
to move the sand a few inches to be piled against the obstacles.
Vegetation holds its place on the loose materials until, at length, a
dense growth of oleander and cedar render the deluge-like rains
wholly ineffective. The same condition exists along railroads within
the drift covered areas of the United States. ]\Iany of the through
cuts are in drift gravels, with no trace of consolidation, yet their
walls show the steady advance of plants in spite of rain and the
steep slope.

The resistance which vegetation offers to erosion is manifest on
a grand scale in the tropics, where growth is luxuriant and the rain-
fall extreme. The writer has had opportunity to examine at close
range fully 200 miles of the Venezuelan and Colombian coast, much
of Trinidad, about 50 miles of the Jamaican coast, as well as much
of the Pacific coast of Central America. There are some localities
where the rock is not consolidated and vegetation cannot maintain
itself. Such as gains rooting toward the close of the wet season is
killed during the dry season and rain finds only the unprotected sur-
face on which to act. But such areas are of limited extent. The
slopes along the coast are usually quite steep and the stratified rocks
commonly dip at a high angle. Landslides, owing to this structure,
are not rare and they leave a scar on the surface which persists for
years ; but aside from those merely temporary interruptions, vege-
tation is practically continuous on even the steepest slopes. The
Jamaican conditions are especially instructive. Where vegetation
was destroyed by fire in some extensive areas, Guinea grass has
taken possession of even the steepest slopes, giving great spaces of
bright green, which are notable features of the scenery — and this in

127

530 STEVENSON— FORMATION OF COAL BEDS. [November 3,

spite of the excessive rainfall. During November of 1909, the rain-
fall in the mountains of Jamaica was of unprecedented volume, there
being at one locality 120 inches in eight days, while in others there
were 20 to 30 inches within one day. Banana plantations, with
unprotected soil, were washed down the hills and the plants became
projectiles with which the flood destro}"ed vegetation on the low-
land; but the forest remained almost uninjured and the litter cover-
ing the surface around the trees was practically undisturbed. Where
the land was protected by trees, damage was confined to gullies
digged by fallen trunks pushed forward by the water. These gullies
widened in soft materials and trees, tumbled into the torrent, were
carried to the lowland, where they were deposited, pele mele, with
mineral matter on the cultivated land. Nowhere in the whole area
w^as there evidence that rainfall did any serious injury to either
forests or the forest litter.

Cornet's'-* observations in the Congo region are to the same efifect.
Where the dry season is prolonged, plants are practically dried bv
desiccation, so that the first rains do great damage ; in such localities,
this is so serious that vegetation cannot re-establish itself. Rut,
near the equator where rains are almost constant, the forest quickly
reoccupies areas which man has cleared. Even in regions with a
long dry season, the bottoms of the valleys, owing to dampness, be-
come forested and that puts an end to the action of the wild waters
— it may cause even diversion of streams. Clearing of forests lays
the humus open and it is carried ofi^ to be spread elsewhere, there to
enrich the soil. This actually occurs in many valleys, giving what
Dupont has termed tcrroioir; but in the broad alluvial valleys, where
humidity prevails throughout the year, vegetable detritus accumu-
lates on the surface and gives a formation of humus sitr place.

It matters not where one looks, the conditions are the same.
Geikie,"^ familiar with the Highlands of Scotland, where bogs in the
heath stage cover great areas, says that the surface of a district pro-

' J. Cornet, " Les depots superiiciels et I'erosion continentale dans le
bassin du Congo," Btill. Soc. Belize de Geologic, Vol. X.. 1897, Mem., pp.
44-116.

'".A. Ceikie, "Textbook of Geology," 3d Ed., London, 1.S93, p. 475.

T28

19"] STEVENSON— FORMATION OF COAL BEDS. 531

tected by a thin layer of turf, is denuded with extreme slowness
except along the lines of its watercourses. Indeed, the evidence is
wholly clear to every one who has crossed Scotland by way of the
Caledonian canal, which utilizes a chain of small lakes, fed by streams
rising in the Highlands and descending with rapid fall. The lakes
are not turbid, they rarely show blocks or chunks of peat where the
streams enter, the only evidence of vegetable matter being coloration
of the water by salts of organic acids leached from the peat. The
same condition exists elsewhere in Scottish lakes.

Many years ago. Marsh" wrote elaborately respecting the pro-
tective influence of vegetation and the disastrous consequences fol-
lowing removal of forests. He recognizes that humus can absorb
almost twice its weight of w-ater, which it surrenders to the under-
lying soil and becomes ready to absorb more. Twigs, stems, fallen
trunks and the rest oppose the rush of water and break into small
streams any larger ones formed by union of petty rivulets. He cites
many works, reporting official as well as private studies — all record-
ing the same results.

In the French Department of Lozere. which was among those
most seriously injured by the inundation of 1866 — caused by rains,
not by melting snow — it was remarked everywhere that " grounds
covered with wood sustained no damage even on the steepest slopes,
while in cleared and cultivated fields the very soil was washed away
and the rocks laid bare by the pouring rain." Marsh cites Foster,
who describes an area with slope of 45 degrees, which consisted of
three sections : one, luxuriantly wooded, with oak and beech from
summit to base ; a second, completely cleared ; a third, cleared in
the upper part but retaining a wooded belt for one fourth of the
height from the bottom. The surface rose 1,300 to 1,800 feet above
the stream flowing at the foot. The first section was wholly un-
scarred bv the rains ; the second showed three ravines, each increas-
ing in width from summit to base ; while the third, of same superficial
extent, had four ravines widening from the summit to the wooded
belt, in which they became narrower and soon disappeared. He

" G. P. Marsh, " The Earth as Modified by Human Action," New York,
1874, pp. 232-238.

129

532 STEVENSON— FORMATION OF COAL BEDS. [November 3,

refers to his own observations that, in primitive regions, running
streams are generally fringed with trees and that even now in for-
ested areas of the United States trees come almost to the water's
edge, so that the banks are but slightly abraded by the current. He
cites Doni respecting the Sestajone and Lima, two streams rising in
the Tuscan Appenines and flowing into the Serchio. In rainy weather
the volume of the former is only about half as much as that of the
latter and its water limpid ; whereas the water of the latter is turbid,
muddy. The drainage areas are almost equal, but the Sestajone
winds down between banks clad with firs and beeches, while the
Lima flows through a cultivated, treeless valley.

The writer had opportunity in 1910 to observe the effect of heavy
rainfall on the steep wooded slopes in central France, where the
rocks are resistant gneisses and granites — a condition much like that
of the White mountains. The rainfall during that summer was not
merely in excess, it was extraordinary. The showers came suddenly
and often resembled the cloudbursts of mountain areas within the
United vStates. In many parts of the area, the gorges are deep, with
walls often exceeding 35 degrees, at times exceeding 45 degrees.
Many gorges have densely wooded walls ; many others have a some-
what scanty growth, scattered over the rocky slope with plants grow-
ing here and there in decomposed material occupying clefts or accu-
mulated behind projecting craggy points. During some showers, the
water ran oft' exposed places not in rills but often in broad continuous
sheets and the streams were converted into roaring torrents. More
than once, after one of these almost cataclysmic rains, the writer
passed through some of the gorges and was surprised to find that,
apparently.noinjury had been done to vegetation on even the steepest
slopes. Tender plants, growing in handfuls of loose material on
projections, seemed to be unharmed. The streams were followed
for many miles, but they had received only rare stems of trees from
undermined banks and the eddies showed no accumulation of plant
material. Trees, lining the streams and in many cases growing
down to almost the low water line, gave no evidence of having
been subjected to the force of a dashing torrent. Tlie conditions
differ from those, with which every one is familiar, only in that they

130

19"] STEVENSON— FORMATION OF COAL BEDS. 533

are on a larger scale. The almost vertical walls of railroad cuts
through hard rock are adorned by small plants growing in clefts or
even by trees in similar position. These have grown in spite of
rains, which threatened to wash away the little soil on which they
depend. But the rains are as powerless against plants in railroad
cuts as they are against plants growing in like conditions on the walls
of Alpine gorges or of canyons in the Sierra and the Rockies.

River Floods. — The floods of rivers have much in common with
those of torrents, for most rivers are more or less torrential in their
upper reaches ; but there are noteworthy differences, aside from those
due to volume. The topographical conditions required for torrents
are wholly unlike those amid which great rivers exist. Torrents
flow, for the most part, in narrow valleys with here and there some
wider portions in which are insignificant floodplains ; but rivers
usually flow in broader valleys, have less rapid descent and are bor-
dered frequently by extensive floodplains. Rivers entering the At-
lantic along the eastern coast of the United States empty in most
cases into estuaries, which occupy the drowned lower portion of the
valley and conceal the floodplain ; but the condition is different in the
vast interior basin where many great rivers find discharge through
the Mississippi channel. Each important tributary of that stream
flows for long distances through broad lowlands, which fuse with
those of the Mississippi, extending from above Cairo to the Gulf of
Mexico and constantly increasing in width toward the south. The
coast and the interior types must be considered separately. Illustra-
tions of river floods will be selected mostly from those of the United
States, partly because the conditions seem to be unfamiliar to many,
and partly because the topographical relations of the central Missis-
sippi region are much like those supposed by some to have existed
during the coal-forming periods.

Rivers of the Atlantic Coast. — Shaler,^^ in describing several
northward flowing streams of eastern Massachusetts, says that the
floodplain is in direct communication with the present margin of the
river, so that a very slight rise sends water over the whole of it.

^^ N. S. Shaler, " Fluviatile Swamps of New England," Amer. Journ. Sci.,
3d Ser., Vol. XXXIII., 1887, p. 203.

131

534 STEVENSON— FORMATION OF COAL BEDS. [November 3.

The streams, though draining comparatively small areas, carry an
enormous amount of water in flood time. At low water, the river
extends for some distance through reedy flats on each side of the
flowing stream. The swamps, which are without Spliagnmn, may
be divided into three classes : those, formed in areas so frequently
overflowed and so penetrated with water that they cannot afford a
site for perennial shrubs, are occupied by rushes in the' lower por-
tions and by grasses in the upper ; those, occupying a narrow belt in
which the grasses give place to various bushy and low growing
plants, among which alders are the prevalent forms ; then, in some
places, a third class, a wide field of swamps, really very wet woods,
covered with water not more than twice a year and usually two or
three feet above the ordinary inundations. The vegetation is con-
tinuous from the lower bench to the wet woods and it is able to resist
the flood, though the mass of water is very great and the current very
rapid. During flood these streams are almost torrential.

The rivers of Maine tell the same story. The Androscoggin,
Kennebec and Penobscot are all liable to sudden floods and the fierce
rush of water is reinforced by logs cut for timber. But the banks
of those streams are covered with bushes and trees to within a foot
and a half of the August stage of water; the flood, though aided by
the logs, has not succeeded in tearing out these trees, but the trees
have seized the logs, which may be seen for long distances entangled
in the bushes. Islands in the Androscoggin have trees 40 feet high,
against which the floating timber has lodged.

The Connecticut river, draining a great part of the White moun-
tains as well as of the Massachusetts highlands, flows for nearly 200
miles in a broad valley, rising in terraces. It is subject to great
floods, for much of the rugged region around its headwaters has
been cleared. The writer has ridden several times for a distance
of 150 miles along the banks soon after high floods, which had over-
flowed the second bottom, 15 to 20 feet above ordinary low water.
Loose material, twigs and fallen branches, which had become dry
but not decayed, had been removed to be deposited in eddies or on
the bottoms. Ikit trees and bushes growing on the lower bottom or
on the banks down to within a foot of low water, were not removed.

1.32

I9II.] STEVENSON— FORMATION OF COAL BEDS. 535

Many of those are old trees which had withstood floods for more
than a century, others were very young ; but the age mattered nothing,
the saphng resisted as well as did the older tree, provided only that
it was rooted in material that would not soften during the flood.
One great flood had poured over the second bottom in the late sum-
mer when the maize had attained its height. But it did not tear the
plants from the soil ; pressure against the broad leaves sufficed only
to prostrate the plant ; none was removed.

xA.t the same time, the eft'ect of the flood was shown by trees on
the lower bottom, for those 25 or more feet high, if slender, were
bent down stream. Those with broad spreading crowns were affected
b}- pressure at the surface of the current. No doubt, if the flood
had been repeated at intervals of two or three days, not a few of
those trees would have been overturned ; but, once overturned against
their neighbors, they would tend to protect the others by increasing
the density of the mass and so acting as breakwaters to divide the
flow. The flood had no effect where the vegetation was dense, the
close growth evidently reducing the current to gentle movement.
Croppings of peat bogs, i to 3 feet thick, appear at many places in
the banks. Such bogs suft"er no injury except by undermining; in
which case, a floating log occasionally tears off a piece.

The floods of the Passaic in New Jersey and of the Susquehanna
have been described in several publications. They are more disas-
trous than those of the Connecticut, from a pecuniary point of view ;
but those rivers in flood are no more effective than the Connecticut
in the struggle against vegetation.

The Potomac river, though of rather rapid fall, flows in a broad
shallow channel, an anomaly due in great degree to the relation
between its normal stage and its freshets. The flood of June i and
2, 1888, the greatest on record, was described briefly by McGee.^^ The
height of water at Washington was no greater than during freshets
caused by ice jams, but, above the limit of tidal influence, the volume
of water and height of rise exceeded any previously recorded. The

''W J McGee, Tenth Ann. Rep. U. S. Geol. Survey, 1890, "Administra-
tive Report," pp. 150-152.

PROG. AMER. PHIL. SOC. , L. 202 JJ, PRINTED NOV. I5, I9II.

133

53G STEVENSON— FORMATION OF COAL BEDS. [November 3,

discharf^e was thirty-eight times as great as that during the abnor-
mall}- wet sinunier of 1889; five hunch-ed and seventv-nine times that
of the average low water discharge ; it closely approximated that of
the Mississippi in ordinary years and was two fifths of the discharge
by that river during the flood of 1858. At Great Falls, the torrent
was OIK' third of a mile wide and 150 feet deep. This was a flood
of unprecedented extent, such as might not be repeated in centuries.
It should afford full opportunity for determining the ability of floods
to remove vegetation. As McGee entered into no detail in his admin-
istrative report, the request was made that he would give such infor-
mation as seemed proper. His letter" is in complete detail and the
following citations are taken from it.

" Tlie most impressive river flood I ever saw occurreLl in the Potomac
several years ago, wlien during June a series of rains occurred in such
order about llie headwaters as to raise the river far above any high stage
previously recorded — indeed I inferred from its effect in l)ending smaller
trees in connection with the undisturbed attitude of the older trees that it
far exceeded any flood of the preceding 150 years. Tlie discharge was not
accurately measured, because the flow was too swift to get a weight into
tile water, -1)ut approximate measurements gave a discharge comparable with
that of the Mississippi at ordinary stages. After tiie water sulisided I went
over the flooded ground with care; and tliis is what I found — the bottom
being irregular, chiefly wooded, partly in field and pasture; in the woods,
frees of less than, say, a foot and a half in cHameter, were bent down stream
and largely robbed of foliage, and a few were broken off, leaving snags;
the higher trees had generally lost branches and most of their foliage (the
water having risen forty to sixty feet, or well toward the tops of the highest
trees) ; here and there, esiiecially near llie chamiel, a tree or clump of trees
had been uprooted and swept away, thougli not more than say one or two
per cent, of the wood in tree or branch was gone. Here and there in the
woods, where tlie current was concentrated by rocks or large trees, a gully,
generally two or three feet deep, as ni;in\- yards wide and as many rods
long, had been cut out; elsewhere, especially where rocks and trees had
slackened the local current, tliere were bars and banks of sand ; and gen-
erally throughout the w'oods there was a layer of silt, of course, left chiefly
by the subsiding waters overspreading the soil — which usually was unmodified
otherwise. From a little field, in-eviously on the l)ottom, a short distance
above Georgetown, the entire crop and the soil to ])low-depth or more was
removed; and in a sloping and somewhat rocky tract of pasture land, up-
stream from the field, the sward was irregularly furrowed by gullies
ordinarily a few feet deep and as many yards wide — the number being such

'*0f December 6, igio.

134

I9III STEVEXSOX— FORMATIOX OF COAL BEDS. 537

that perhaps a quarter or perliaps a third of the sward was removed. The
furrowing in this pasture, by the way, represents the most extensive flood
removal of sward that I have ever seen. Now considering the translocation
of material generally by the flood, it is clear that despite the favora1)le con-
ditions due to abundant vegetation and to a higher declivity of the flood
than that of the normal stream, the ratio of organic matter moved to the
inorganic sediment was trifling. . . . What is true of that flood is, I am con-
vinced, true of river floods generally — while the flooded river generally has
its transportative capacity greatly increased, the material transported is chiefly
inorganic, so that the resulting sediments are mainly mud, silt or sand, rather
than organic accumulations."

The writer rode through much of the area two months after the
flood had subsided. The chief evidence of great flood presented by
the vegetation consisted of somewhat inchned trees, deposits of
debris in branches of trees at a distance above the stream and an
occasional furrow in the sod. These furrows were produced wlien
the water in swirling around a projecting rock worked under the
sod and, soaking the materials below, burst the cover, so opening
the way for making a gully. In the forested portions, the litter
seemed to have suffered very little injtiry beyond, as noted by
McGee, receiving a cover of inorganic sediment.

Murphy^"' has described a flood on Willow creek in Morrow
county, Oregon, a stream combining the features of a torrent with
those of a river. The creek, 30 to 40 feet wide and enclosed in
banks 10 to 15 feet high, has a fall of 38 feet jier mile, but, unlike
most of such streams, it flows through a fertile valley, 500 to 1.500
feet wide. The storm causing the flood of 1903 was brief, a cloud-
burst, and the flood had passed in less than an hour. The water
came down as a mass, 20 to 25 feet high, with a slope in front of
about 30 degrees, and it was 500 feet wide. It swept away a great
part of a town which was in its path. Xo details are given respect-
ing the damage done to vegetation, btit some incidental remarks make
the matter sufficiently clear. Referring to methods of determining
the high-water level of floods, he says that trees are the best marks ;
small trees are often bent over and silt or light drift is deposited on
them. When the water pressure is removed, the trees straighten up

" E. C. Murphy. "Destructive Floods in the United States in ifX>3,"
U. S. G. S. Water Sup. and Irr. Paper. 96, 1904. pp. Q-12.

135

538 STEVENSON— FOR.MATIOX OF COAL BEDS. [November 3.

and the drifted material is raised above the high level; but rings of
silt left on trees, all on approximately the same level, show the true
waterline. In this way he determined the extent of the flood. The
houses, made of lumber, were lifted from their foundation and were
dashed to pieces against rocks or trees.

Wilkes^" made use of the same method. In speaking of floods
on the Willamette river of Oregon, he says that the sudden rises of
the stream are remarkable, the perpendicular height of the flood
being at times as much as 30 feet, the limit being marked very dis-
tinctly on trees along the banks. In New South Wales " near the
source of streams, grass is to be seen attached to the trunks of trees
thirty feet above the present level of the water, which must have
been lodged there by very great- floods." This is a commonplace
condition ; the writer observed it at the head of Sacramento bay in
California almost forty-five years ago. He saw many bunches of
drift stufif entangled in branches of trees at 10 to 15 feet above the
water level, and he was astonished by the fact that so great a flood
had done no injur}- even to the shrubs growing among the trees.

Rk'crs in Great Interior Basins. — Excellent descriptions of floods
within the Mississippi-Missouri area are given in reports of the
Ignited States Weather Bureau, tliose by Morrill and FrankenfielcF'
being the most comprehensive.

Man's skill has brought about great changes in the lowlands of
the Mississippi. The fertilit}' of that region from the mouth of the
Ohio to the Gulf of Mexico early led to settlements at many places.
But the periodic floods of the river rendered agricultural operations
precarious and levees were constructed for protection. Eventually the
construction of such levees was assumed by the Federal government
and they now protect a vast area from overflow. The region, now
exposed to devastation under ordinary circumstances, is very small,
but, during abnormal floods, the levees sometimes give way and

'" C. Wilkes, " Narrative of the United States Exploring Expedition,"
1845. Vol. IV., p. 358; II.. p. 269.

" P. Morrill, " Floods of the Mississippi River." Rep. Chief of Weather
Bureau for 1896-7, Washington, 1897, pp. 371-431. H. C. Frankenfield, "The
Floods of the Spring of 1903 in the Mississippi Watershed," Weather
Bureau l>ull., 1904.

13G

•9'-l STEVEXSOX— FORMATION OF COAL BEDS. 539

crevasses are formed — at times half a mile wide — through which a
stream pours with amazing velocity. The conditions are materially
different from those prior to settlement of the region, when the
floodwaters spread over an area of 100,000 or more square miles ;
the energy of the flood stream, when it bursts through a crevasse, is
much greater than when there were no levees. This, however, is
unimportant, for if the later floods are incompetent to inflict serious
injury upon lands protected by vegetable cover, the incompetence
must have been more marked when the natural conditions existed.

The protection afl'orded by levees is shown by constant decrease
in extent of the flooded area; the flood of 1887 overflowed almost
30,000 square miles below the mouth of the Ohio; that of 1897 cov-
ered somewhat more than 13.000, while the area was reduced in 1903
to somewhat less than 7,000 — and in this year the extent would have
been much less if the new levees at critical localities had been com-
pleted so as to resist the very high water. Rivers carrying much
detritus and subject to flood build low levees in their passage through
the lowlands. The Mississippi constructed such ridges for long dis-
tances, thus preventing return of the floodwater, much of which is
ponded in swamps and gradually finds its way to the river farther
down. This secondary drainage complicates the problem of recla-
mation.

The ^Mississippi floods, imlike those of the Xile, are very complex,
for below the mouth of the Ohio the river receives great tributaries
from the east and the west, whose floods rarely coincide ; while the
upper Alississippi, receiving the iMissouri and other rivers, has its
own periods of flood. The source of floodwaters is in the conti-
nental storms, arising in the west or southwest and moving toward
the east-northeast. The eft'ects are felt first in the lower Missis-
sippi, which is filled by streams entering from the west ; the storm
advances to the western ridges of the Appalachian where rise streams
forming the Ohio, Cumberland and Tennessee rivers. The heavier
rains on the Appalachians pour out chiefly through the Ohio but the
other streams contribute a great mass. Important floods in the
eastern tributaries occur in the spring months, when heavy rains are
reinforced by melting snow. The upper Mississippi is not an impor-

137

540 STEVENSON— FORMATION OF COAL BEDS. [November 3,

taut factor in respect of (|nantity, but its swell, coming later than the
others, often prolongs the stage of high water. 11ie western rivers,
entering below the mouth of the ( )hio, are the Arkansas, Red,
Ouachita and >'azoo. all of which descend into lowlands, where they
meander for a long distance before reaching the Mississippi. The
condition in this drainage area is that of ra])idl_\- Howing streams
emerging from highlands on an immense area of lowland, most of
which, unless protected, is subject to overflow.

r>oth l'"rankenlield and Morrill emphasize the gradual rise of
Hoods within the open area. h'rankenlield gives the record for 1903.
'Die gauge showed at

Fret. Feet. Feet

Cairo, Jan. jS. 17.5 Marcli S, 45 March 15, 50.6

Mcnipliis. I'\'I). I, 10.8 ]'\"1). 22. 33 Mar. 20, 40.1

Vickshur.u-, l-'ch. .|, 21.0 Mar. 3, 45

New Orleans, I'd). 8, c).i k'el), 26, 16 Apr. 6. 20.4

The advance was deliberate, the lirst wave requiring four da}s
for passage from Cairo (at the mouth of the Ohio) to Memphis and
seven (la\s thence to New ( )rleans. The rise was gradual at Cairo,
being a foot and a half dail)' for i,() days to March 8- — which was
thought to be remarkably ra|)id — and much less thereafter to the
crest; at Memphis, it was one foot for 21 clays and onlv one fourth
of a fool for v:\c\] of the remaining _>S ; at \'icksburg, barely nine
tenths of a fool during each of the first 27 davs ; while at New
Orleans, the dail\ rise averaged little more than one fifth of a foot
throughout the whole ]H'riod. '^Idie great mass of the water came
from the ( )hio, but the \\c(\ and ( )uachita, entering from the w'est,
were abnormall\ high; at New ( )rleans, the water was at or above
danger line for 85 days.

When one studies the reports of local observers, as given in the
publications from which this synopsis is taken, he is surprised bv
the nature and extent of damage within the Hooded areas. Artificial
protection is almost unknown along th.e upper Mississij^pi (above
Cairo) as well as along the Missouri and its tributaries. Floods
have free course in the low-lying prairie regions of Illinois, Iowa
and Kansas as well as in jiortions of Missouri, and there one should
expect to fmd record of the greater disaster. Morrill has compared

138

I9II.] STKVKNSON— FORMATION OF COAL BFDS. 541

the flood of 1897 ^\'t'i 'ts predecessors as far back as 1858 and he
has given details in all parts of the drainage area for that of 1897.

In 1897, the Ohio river was out of its banks everywhere from
Pittsburgh to Cairo and the tributary streams, also in high flood,
were miles wide for long distances, the "bottom," at times, being
covered with 20 feet of water, while the overflow reached into the
upper portions of cities along the banks. At the mouth of the river,
the lowland was flooded for 4 to 6 weeks and the city of Paducah
in Kentucky was flooded for 7 weeks. The river rose 50 to 60 feet
along the whole distance of more than 600 miles from Pittsburgh to
Cairo. Similar conditions prevailed along the Tennessee river, which
for 60 miles was 2 miles wide, reaching to the hills on both sides.
In the upper Mississippi region, the river s]:)read from blufl' to blufl^,
3 miles wide for 147 miles along the Iowa border, and a great area
of farming land in lliat state was inundated. Imperfect levees gave
way and along the Illinois river an area of 500 s(|uare miles was
flooded, making a continuous body of water from the Illinois to the
Mississippi. Central Arkansas was submerged for long distances
along the Arkansas river; while below Cairo, several levees gave way
and the flooded district in that region embraced more than 13,000
square miles.

When one comes to sum up the effect of this disastrous flood, as
given by the local observers, he discovers, that as far as the geolo-
gist is concerned, they were comparatively insignificant. The damage
to manufacturing interests by destruction of machiner\ and by de-
posits of mud in mills was very great ; the railroads lost much through
washing out of embankments, the ruin of bridges and the removal of
ties and lumber; but loss to the farming population was only mod-
erate because Weather Bureau warnings led them to transfer movable
property to higher land. Small houses, l)arns, lumber and other
loose material were floated ofl' to be used as battering rams against
bridges; but, for the most j^art, farms overflowed by the ra])id cur-
rent were little injured. Where wheat had come U]). it was drowned,
not removed ; where seed had been sown, it rotted ; where the
flood became sluggish, it left a deposit of sand, which made the land
worthless, but elsewhere, as soon as the water withdrew, the farmer

i:}9

542 STEVENSON— FORMATION OF COAL BEDS. [November 3.

immediately set about replanting. The great flood had done little
injury, had hardly disturbed the soil of cultivated fields.

Frankenfield tells the same story for the flood of 1903. The
sunken area of New Madrid was filled and the water, being more or
less ponded, left deposits of sand. In the lower Mississippi area,
crevasses permitted great overflow, but there was no injury to farms,
aside from drowning of the crops, for which there was ample com-
pensation in the form of a rich alluvial deposit. The Ohio river
was more than two miles wide in many places between Cairo and
Louisville. Near Evansville, Indiana, 300,000 acres of maize and
30,000 acres of wheat were covered, but the only loss was that of
3,000 acres by drowning. The local observer at Evansville reported
that the damage would have been much greater if the water had not
remained in constant motion. At Topeka in Kansas, the flood was
diverted from the river by obstructions piled against a railroad
bridge and the water, loaded with sand, swept over a wide area.
Crops were ruined and the nursery fields near Topeka v>-ere covered
with sand which buried the young trees. These instances are merelv
illustrations of conditions prevailing throughout the whole area.

The reports contain no reference to the disastrous efl^ects of such
floods upon areas covered with forest or otherwise protected by
close vegetable growth, which at first glance seemed strange, be-
cause wooded areas occupy much of the lowland or bottom regions.
But the omission was due not to neglect but to absence of anvthing
to record. Reproductions of photographs given by Frankenfield
and Morrill show that trees and even shrubs were undisturbed amid
the rush of water and coarse sand. The writer asked the former
for information respecting the matter. The reply was

" During the Mississippi floods no forests are uprooted and no bogs are
torn away. A considerable quantity of sand is sometimes carried down and
deposited when the velocity of the water decreases, either by contact with
obstruction or by reason of decrease in inclination of the floodplain. It is of
course conceivable that the mass of water rushing through a crevasse carries
away a quantity of vegetable matter and perhaps some trees, but the area
would necessarily be limited. The true Mississippi flood moves along very
sedately, carrying only the enormous amount of alluvial matter in suspension,
but very little indeed of foreign matter. Previous to the era of levee con-

140

>9"1 STEVENSON— FORMATION OF COAL BEDS. 543

struction, the forests do not appear to have been seriously disturbed by
floods."

An observation by McGee^** is in place here. The Mississippi,
as it flows past northeastern Iowa, meanders through a densely
wooded floodplain, four or five miles wide, now in one main and
half a dozen subordinate streams and yet again in numerous large
and small channels. But this plain is flooded each year ; according
to writers already cited, the river at times covers the whole plain
from blulif to blufi^ as a rapid stream.

Lyell,^'' in referring to the 1844 crevasse near New Orleans, savs
that the water poured through at the rate of ten miles an hour, inun-
dating the low cultivated lands and sucking in several flat boats,
which were carried over " the watery waste " into a dense swamp
forest. He mentions that the great Carthage crevasse was open
during eight weeks and that nothing was visible above the flood
except the tops of cypress trees growing in the swamp.

Humphreys and Abbot-'' state that the bottoms of the Illinois
river are two to ten miles wide and raised only a few feet above the
usual level of the river. The greatest part of this swampy country
is included in the "American bottom." The Kaskaskia flows with
crooked course through a heavily wooded alluvial bottom, over-
flowed eight or ten feet by freshets. These authors emphasize the
fact, too often ignored, that lowland areas are usually well soaked
by rains preceding the floods and the swampy areas become covered
with water, so that when the overflow^ comes, it finds everything
prepared for resistance.

Lyell-^ had the weird experience of descending the Alabama
river in time of high flood. At night the passengers were startled
by crashing of glass and partial destruction of the steamer's upper

''W J McGee, "Pleistocene History of Northeastern Iowa," Eleventh
Ann. Rep. U. S. Geo!. Survey, 1891, p. 204.

" C. Lyell, " Second Visit to the United States of North America," Lon-
don, 1850, Vol. II., p. 169.

^ A. A. Humphreys and H. L. Abbot, " Report upon the Physics and
Hydraulics of the Mississippi River," Reprint, Washington, 1876, pp. 38, 66,
76, 82.

-'C. Lyell, "Second Visit," etc., Vol. II., pp. 51, 141.

141

544 STRVENSON— FORMATION OF COAL BF.DS. [November 3.

works. 1'lic boat liad "got among' the trees." The river banks are
fringed with canes over which decichions cypresses tower, while
farther l)ack is the evergreen pine forest. During floodtime, the
actual channel is very narrow, as the l)ranches of the high trees
stretch far over the water, so that, when the stream has risen 40 or
50 feet, nuich skill is require<l to keep the way between them. At
that lime, the adjoining swamps and lowlands arc inundated far and
wide, r.ut this ilood does practically no injiu-y to the forest directly
in the path of its strongest cm-rent or to thai farther back where the
current is less raj^d. L\ell found the same condition on the Mis-
sissippi delta, where the ilood waters, though laden with silt, have
not injured even the willow saplings.

The Hoods of great rivers in other lands exhibit the same phe-
nomena.

According to 1 lumboldt,-"-' the Hoods of the ( )rinoco l)egin soon
after the vernal e(|uinox and attain their maximmu in July. The
water remains at ])ractically the same height until August 25, after
which it falls more slowly than it rose. Its bounding region is
nuicli like that of the lower Mississi])pi and the flooded area is as
large as luigland though less than the ex])osed regi(Mi along the Mis-
sissipjii. The delta area is alwaxs wet except in some petty eleva-
tions, which are dry for brief periods. The surface is completely
inundated during several months each year. lUit it is covered with
a dense growth of Mauritius palm in which the inhabitants construct
raised platforms, on which they reside.

Wallace-^ has described the broad level area extending to 20 or
30 miles from the main stream of the Amazon and extending for
long distances along the main tributaries. This is Hooded at every
time of high water. It is " covere<l with a dense forest of lofty trees,
whose stems are every year, during six months, from ten to forty
feet under water." Much of the Hooded area at the mouth of the
Amazon is covered with the mirite palms, Maitritia flcxiiosa and
M. v'mijcra.

'"^ h. lluinh.ildt, " Person.il Xarrativc," Bohn I'.ng. Ed., 185.', Vol. HI.,
p. 8.

-' A. R. Wallace, " A Narrative of Travels on the Amazon and Rio
Negro," London, 1853, pp. 410, 436-

142

■9.. I STl-.VKNSON— FORMATION OF COAL BEDS. 545

Kuntze-' sailed almii^' [lie I .(iiiri'iK^o river tlirou.i^li tlic vasl wDodcd
svvani]) occupyiiij; lliixx' dcj^rccs of laliliidc. Tlu' rcmai-kahk- fea-
ture, for liiiu, was the absence of transported vej^etable detritus.
Rare fragments of the swamp ari' lorn off during high water, but
these consist not of detritus l)ut of Hving plants; and these frag-
ments become stranded elsewhere or go to sea broken into bits.
'I'lie ri\er water is brownish. l'"ver\ where on the Paraguay as well
as on its tropical an<l subtropical tributaries, nwv linds the dense
forests coming down to the river, which are overllowed during
lloodtime ; yet there is no outgoing organic detritus except frag-
mentary driftwood from trees, which tumbled in from midermined
banks. Kuntze followed all the great streams above the mouth of
the Parana.

Liviiigstone-'' has given admirable illustrations of the resistance
offered by vegetation. Many times he encountered the rivers in
Hood, when water s])read tar owv the plains. The conditions within
the area of the Chobe ;ind in that of the I.ecambxe are of the familiar
type, lie reached the l.t't'ba river at the beginning of the rainy
season. The river is bordeied by a ])Iain, at least 20 miles wide,
where, at that lime, the water was already ankle deep in the slial-
lower ])arts, while on the Lobale ])lain it was thigh deep and impass-
able. This Hooding was not due to the river, for that had not over-
flowed its banks. The condition was the same as that observed prior
to the coming of great Hoods in the Mississippi lowlands. The
Lobale plains are too nearly level to permit the r"ain water to How
ofT rapidly; while the thick sward, so dense as to conceal the water,
prevents furrowing of the surface and formation of rivulets. On
approaching the Kasai river, he crossed valleys, half a mile to a mile
or more in width, with clear fast-Howing water almost chin deep.
One, half a mile wide, was deeper and the men crossed it by seizing
the tails of their oxen. The extremely rapid cm"ri'nt "soon dashed
theniagainst the o])positebank." Themiddle of the Hood was where
a rivulet exists during most of the year. P'Oggy ])laces are extensive

'' O. Kuntze, " (Jeogeiietisclie Bcitriige," Leipzig, iH<;5, pp. 67, 68.
"'I). Livingstone, "Missionary Travels and Researclies in Soutli Africa,"
Now York, 1S5K, pp. 191-105, ^34, 235, 333. 363, 364, 39-'.

143

546 STEVENSON— FORMATION OF COAL BEDS. [November 3,

on both sides of the river, but " even here, though the rapidity of
the current was very considerable, the thick sward of grass was
' laid ' flat along the sides of the stream and the soil was not abraded
so much as to discolor the flood." In his later work,-" he offers an
explanation of the conditions.

" The shallow valleys, along the sides of which the villages are clotted,
have, at certain seasons of the year, rivers flowing through them, which at
this time formed only a succession of pools, with boggy and sedgy plains
between. When the sun is vertical over any part of the tropics on his way
south, the first rains begin to fall and the effect of these, though copious, is
usually only to fill the bogs and pools. When on his way north he again
crosses the same spot, we have the great rains of the year, and the pools
and bogs, being already filled, overflow and produce the great floods whicii
mark the Zambesi, and probably in the same manner cause the inundations
of the Nile. The luxuriant vegetation, wdiich tlie partial desiccation of many
of these rivers annually allows to grow, protects these bottoms and banks
from abrasion, and hence the comparative clearness of the water in the
greater floods."

Darwin and Airs. Agassiz tell a similar story respecting the
Parana and the Amazon ; Cameron and Stanley have shown the con-
ditions in the region of Lake Tanganika and the Sudd of the Nile
has been described by Baker, Willey and other travellers. Every-
where, the conditions are the same ; living vegetation and even
humus are practically proof against the action of floods.

The Plant Materials Transported by Rivers. — While it is true
that a vegetable cover is an almost complete protection against ero-
sion and that neither rain nor floods have much ability to remove
rooted plants or to take off the superficial coat of decayed or decay-
ing plant-stufi^, still the fact remains that rivers do carry away great
quantities of plant materials in one form or another. The quantity
brought down by a single torrent may be insignificant ; even that
borne bv a river of considerable size may not impress an observer
as important ; but when one reaches the lower Mississippi, draining
an area of not less than 1,250,000 scpiare miles, fed by tributaries
from the Rockies at the west and the Appalachians at the east,
which flow for long distances in broad alluvial plains, he finds a

-"■'Narrative of an Expedition to the Zambesi and its Tributaries,"
New York, 1866, p. 554.

144

19".] STEVENSON— FORMATION OF COAL BEDS. 547

mass which seems to be ahiiost inconceivably great. On some
streams he finds or learns of huge log barricades, apparently afford-
ing ample confirmation of Ochsenius's barricade theory ; along others
the river bed is set with " snags," impeding navigation ; while along
the main stream the casual observer is apt to regard the floating
trees and other debris as an almost continuous mass.

It is equally certain that a vast amount of finel}- divided vege-
table matter, derived from chafing of logs and trunks during their
voyage as well as from partial decay of the floating plants, is carried
by all rivers. It is true that studies of the Mississippi, in flood and
in ordinary stages, have shown that the quantity in the silts is utterly
insignificant when compared with the inorganic materials, but it
suffices, during decay, to give off a notable discharge of gas in the
outer area of the delta. The suggestion has been made that vege-
table matter, minutely divided, may explain the fertility of the Nile
deposits. According to Reclus, cited by Marsh,-" it has been com-
puted that the Durance river, fed by torrents of great erosive power,
carries down annually enough solid matter to cover 272,000 acres
with a deposit two fifths of an inch thick, containing more available
nitrogen than 110,000 tons of guano and more carbon than could be
assimilated by 121,000 acres of woodland in one year. The black
waters of the Scottish lakes, of several rivers in Florida, of great
rivers like the Congo in Africa, the Negro and others in South
America prove that an enormous amount of vegetable material is
leached from peaty deposits.

When one considers the mass of transported timber, the- content
of organic matter removed by solution, and reads the more or less
crude estimates of organic stuff's in the detritus carried by rivers,
the mind is staggered and he is almost ready to concede that in this
transportation there is the process fully competent to bring about the
accumulation of coal beds. It is important, then, to ascertain, if
possible, what becomes of this material.

The trees and shrubs carried by the rivers were not uprooted by
the torrents ; they come not from abrupt slopes but from lowlands
where meandering streams undermine their banks and the plants

■' G. P. Marsh, "The Earth as Modified by Human Action," p. 245.

145

548 STEVENSON— FORMATION OF COAL BEDS. [November 3,

tumble in with the rest. Gibbs,-* who saw the spring flood of the
Yukon river in Alaska, relates that

" During tlie liigh stage of water, which lasts for perhaps two or three
weeks, great sections of the heavily wooded banks are undermined and
swept away. The majestic spruce trees and tamaracks and birches, which
covered them, topple over and are swept down by the current along with
immense quantities of drift wood from the forest beds. The entire accumula-
tion, amoimting to thousands of cords of wood, is discharged into Bering
sea, whose restless waves and shifting winds scatter this fuel and pile it on
barren shores, hundreds of miles distant."

The conditions along the Mississippi-Missouri and their tribu-
taries are the same ; when the weakened banks cave, the forest, with
its fallen trunks and litter, finds its way into the water. The masses
of drifted wood in the channels of the Mississippi and some of the
streams entering that river from the west have been mentioned in
nearly all textbooks on geology during the last seventy-five years ;
but in most instances the descriptions have been incomplete, while in
some cases they were sufficiently inaccurate to be misleading.

In the early days, great numbers of waterlogged trees were held
back by their roots and were moored in the silt with their usually
branchless stems pointing down stream. These were the " snags "
which rendered navigation perilous. Fewer of them are encoun-
tered now because a very great part of the drainage area is under
cultivation, but enough are added annually to necessitate the services
of several snag-removing boats along the line of nearly 2,000 miles.
Most of the floating stems find their way to the Gulf, but some are
stranded on the delta during floods. At one time, however, they
were diverted, in chief part, into the Atchafalaya, the first great arm
of the river at the head of the delta.

Darby-^ has told us that the vast ninnber of trees brought down
by the Mississippi were thrown into this arm, through which they
were carried with tremendous speed. The Atchafalaya raft began
to form in 1778, when practically the whole drainage area of the

="0. Gibbs, "The Break-up of the Yukon," Nat. Geog. Mag., Vol. XVII.,
1906. pp. 268-272.

^ W. Darby, ".A. Geographical Description of the State of Louisiana,"
2d Ed.. New York, 181 7. pp. 131-1,^3.

140

I9II.] STEVENSON— FORMATION OF COAL BEDS. 549

river had still its virgin forest, there being only a few, insignificant
settlements west from the Alleghany mountains. By 1816, the head
of the raft was within 2"] miles of the Mississippi. Darby examined
it in that year and reported that it was 20 miles long, 220 yards wide
and perhaps 8 feet deep. As it was not continuous, but showed
many open spaces, he was convinced that a length of 10 miles would
be nearer the truth, thus giving about 4,000,000 cubic yards of loose
material as the total accumulation during almost 40 years, practically
the total supply of floated timber from the area of more than 800,000
square miles. He says that " the tales which have been related
respecting this phenomenon, its having timber of large size and in
many places being compact enough for horses to cross, are entirely
void of truth. The raft, from frequent change of position, renders
the growth of large timber impossible. Some small willows and
other aquatic bushes are frequently seen among the trees but are too
often destroyed by the shifting of the mass to attain any consider-
able size." The channel was opened by the state authorities in 1840
and the raft disappeared.

Details respecting variation of position and duration of material
were not given by those who described the Atchafalaya raft. But
no such lack of information exists respecting the more celebrated
raft of the Red river in Louisiana. That stream, formed by tribu-
taries rising in the higher lands of Texas and Oklahoma, flows for
a long distance through a region of yielding materials, which, in
many places, is densely forested. According to Veatch,^'^ this raft
began to form in the fifteenth century and by the beginning of the
sixteenth, its head was near the present town of Alexandria, some-
what more than 60 miles from the Mississippi river. It consisted
of a series of complex logjams, each filling the channel. These
ponded the river, which found a new outlet above the raft, so that
this, by additions, gradually moved stream, becoming a great irreg-
ular accumulation of logjams and open water about 160 miles long.

^ A. C. Veatch, " Geology and Underground Water Resources of Nortfi-
ern Louisiana and Southern Arkansas," U. S. G. S. Professional Paper, 46,
1906, p. 60.

147

650 STEVENSON— FORMATION OF COAL BEDS. [November 3,

At the time of the early settlements, the foot of the raft was at
Natchitoches, 120 or 130 miles from the Mississippi.

Humphreys and Abbot,^^ writing in 1861, reported that the raft
was an enormous accumulation of drift logs, some floating, some
sunken. The rotting of the logs at the lower end and fresh acces-
sions at the upper end led to advance up stream at the rate of from
one mile and a half to two miles each year, while the retreat at the
lower end was about equal to the gain above. At one time, the
lower end was at Natchitoches but in 1854 it was at 53 miles above
Shreveport, a retreat of about 150 miles. At that time, it was nearly
13 miles long. Above Shreveport to the raft, the river bed was
strewn with logs, stumps and other vegetable debris. The river is
very shallow, 3 to 4 feet deep at low water, and it was about 220
yards wide at the head of the raft, 405 miles from the Mississippi.
Rotting would cause the 13 miles, reported by Humphreys and
Abbot, to disappear within seven or eight years.

The notes given by Humphreys and Abbot were from a casual
examination by their assistant, the matter lying outside of the scope
of their work. The raft was a serious obstruction to navigation,
cutting off the region above from communication with the Missis-
sippi. Congress in 1871 ordered a complete survey, which was made
by Lieutenant Woodruff, whose report, rendered in 1872, gave the
first exact information respecting the actual conditions. Captain
Howell,^" in transmitting the report, remarks that the facts have
been misapprehended even by engineers. " The ' great raft ' itself
dwindles to a mere pigmy in comparison with the popular notion of
its extent and composition." Woodruff, in 1871, proved that the
raft extended along the river for about seven miles, but that through-
out that distance the channel is only partially obstructed. The whole
mass of floating raft was but 290 acres and the whole area of " tow-
heads " or raft resting on the bottom was 103 acres. The towheads
are formed during freshets by accumulations of logs and drift around
a " snag." As the water falls, the pile rests on the bottom and a

^'A. A. Humphreys and H. L. Abbot, "Physics and Hydraulics," etc.,
1876, pp. 21-23.

^'C. W. Howell, 42d Congress, 2d Session, Exec. Doc, 76. p. i.

148

'91 1-] STEVEXSOX— FORMATION OF COAL BEDS. 551

rapid deposition of mud takes place around it. The surface left
above water produces willows, which, growing rapidly and binding
the mass together by their roots, protect it from the washing by sub-
sequent freshets. Woodruff advised removal of the raft, but, to
prevent renewal, he recommended that the narrow part of the river,
in which the raft was forming, be cleared of the willows lining the
banks, which obstructed the passage of large bodies of floating drift.
If this were done, the banks, no longer protected by the vegetable
growth, would cave readily, the river would be widened and the
formations of raft would cease. The removal of the raft was com-
pleted in 1872 and Woodruff afterwards gave a full history of the
obstruction, to which the reader is referred for other details. ^^

Franklin^^ found much floating timber on the Athabasca river in
northwestern Canada. " The river carries away yearly large por-
tions of soil, which increases its breadth and diminishes its depth,
rendering the water so muddy that it is hardly drinkable. Whole
forests of timber are floated down the stream and choke the channels
between the islands at its mouth." It is clear that, on the Athabasca
as on the ]\Iississippi, caving banks yield the supply of drifting
timber. In the same volume, Richardson'^ describes conditions ob-
served along some rivers and lakes within the region traversed by
Franklin's expedition. His statements have been cited by many
writers but so far as the present writer has seen, not in full. They
are as follows, with omission only of some details which are irrele-
vant here. Peace river brings much large drift timber into Slave
river

" and as the trees retain their roots, which are often loaded with earth and
stones, they readily sink when water-soaked and, accumulating in the eddies,
form shoals which ultimately augment into islands. A thicket of small
willows covers the new-formed island as soon as it appears above water and
their fibrous roots serve to bind the whole firmly together. The trunks of
the trees gradually decay until they are converted into a blackish substance

^ E. A. Woodruff, in App. Q, Ann. Rep. Chief of Engineers for 1873,
Separate, pp. 45-61.

^^ J. Franklin, " Xarrative of a Journey to the Shores of the Polar Sea,"
London, 1823, pp. 192, 357, 364, 374, 381.

"J. Richardson, Ibid., p. 518.

PROC. .-VMER. PHIL. SOC. , L. 202 KK, PRINTED NOV. 1 6, I9II.

149

552 STEVENSON— FORMATION OF COAL BEDS. [November 3,

resembling peat, but which still retains more or less of the fibrous structure
of the wood, and layers of this often alternate with layers of clay and sand,
the whole being penetrated to the depth of four or five yards or more by
the long fibrous roots of the willows. A deposition of this kind, with the
aid of a little infiltration of bituminous matter, would produce an excellent
imitation of coal, with vegetable impressions of the willow roots. The same
operation goes on in a much more magnificent scale in the lakes. A shoal of
many miles in extent is formed on the south side of Athabasca lake by
the drift timber and vegetable debris brought down by the Elk river; and
the Slave lake itself must be filled in process of time by the matters daily
conveyed into it from Slave river. Vast quantities of drift timber were
buried under the sand at the mouth of the river and enormous piles of it
are accumulated on the shore of every part of the lake. The waves washing
up much disintegrated vegetable matter, fill the interstices of these entangled
masses and in process of time a border of spurious peat is formed around
the various bays of the lake."

In a later work,^*' referring to the drift timber of Slave river,
he describes the trees as "partially dentided of their branches and
whollv of their bark." The absence of all-important details in Rich-
ardson's account is dtte to the fact that he was not a geologist, but
he was an acute observer, as is evident from the general tenor of
his reports. McConnelP' has supplied many of the details omitted
by Richardson. The sandy beaches and islands along the lower
reaches of Slave river owe their origin to drift timber, which lodges
and soon has the growth of willows noted by that author. But those
islands cause currents, which either destroy them or move them
down stream. Beds of drift timber alternate with clays and sands
on many of the islands and in some instances, constitute a consid-
erable portion of the whole mass. The east end of Big island in
Great Slave lake is fringed by a wide margin of drift timber. When
the interstices have been filled by gradual deposition of sand and the
decav of the wood, a dense growth of willows covers it. The coves
of the main shore show the same features in many places. Atha-
basca and Slave lakes are inland seas, larger than Lake Ontario.

Islands, such as those described by Franklin, are not unusual in

^'J. Richardson, "Arctic Searching Expedition," London, 1851, Vol. I.,

p. 142.

''R. G. McConnell, Ann. Rep. Geol. Survey of Canada, N. S., Vol. IV.,

1890, pp. 63, 64, 74 D.

150

•9«'-J STEVEXSOX— FORMATIOX OF COAL BEDS. 558

the Mississippi river. Humphreys and Abbot''- have described the
process of formation and destruction:

" Driftwood is lodged upon a sandbar. Deposition of sediment follows.
A willow growth succeeds. In high water, more deposition is caused by the
resistance thus presented to the current. In low water, the sand blown by the
wind lodges among the bushes. An island thus rises gradually to the level
of highwater and sometimes even above it, sustaining a dense growth of
cottonwoods, willows, etc. By a similar process the island becomes con-
nected with the mainland, or, by a slight change of direction of the current,
the underlying sandbar is washed away, the new made land caves into the
river, and the island disappears."

When in the temperates such an island, whicli in spite of current
and flood, had grown and had become coated with trees, disappears
through undermining, the vegetation floats away piecemeal ; but in
the tropics the whole mass is bound together firmly by climbing and
other plants, whose roots are interlaced and whose stems embrace
the trees ; so that, when the underlying loose material has been re-
moved, the entangled vegetable matter floats away to be broken up
gradually. Many travellers have referred to floating island of plants
and plant material. Humboldt saw them on the Orinoco ; Mrs.
Agassiz was astonished by their size on the Amazon, where some
were like " floating gardens, sometimes half an acre in extent."
Kuntze saw patches of moderate size floating down the Parana sys-
tem. Miss Kingsley"'-' relates that during high water, the Congo
and Ogowe tear away their banks in the region above brackish water,
where there is no network of mangrove to protect them. Along the
Ogowe, the banks are of "stout clay" and the blocks hold together,
so that they often go sailing out to sea and are seen far from land
with shrubs or even trees on them. Xot all reach the open water,
for many are stranded in the delta region, where they collect debris
from the flood water and become matted with floating grasses.
Eventually they all go to pieces.

De la Beche^° cites Tuckey's Expedition to the Zaire (Congo)

^ Humphreys and Abbot, op. cit., pp. 97, 98.

^° M. W. Kingsley, "West African Studies," 2d Ed., London, 1901, p. 87.
*" H. T. de la Beche, "The Geological Observer," Philadelphia, 1851,
p. 370.

151

554 STEVENSON— FORMATION OF COAL BEDS. [November 3,

as containing the statement that Professor Smith had seen a floating
mass about 120 feet long and probably washed out of the Congo,
consisting of reeds resembling Doiia.v and a species of Agrostis,
among which branches of a Justicia were still growing. Powers*^
saw a floating island in the Gulf Stream in July of 1892. Its area
was estimated at about 9,000 square feet and it carried trees, 30
feet high. It was seen again in September, having travelled more
than 1,000 nautical miles. This, first seen in latitude 39° 5', may
have been torn off from the Florida coast. In every case the float-
ing islands are of small extent and their rarity makes them objects
of curious interest.

Drifhvood. — Great rivers carry immense quantities of trees from
the undermined banks. Where the course of the stream is inter-
rupted by extensive lakes, such as Great Slave or Athabasca, much
of the floating timber becomes scattered and is cast on the shore to
Tdc mingled with the mineral material, which eventually buries it.
When the stream is continuous, some of the drift is cast ashore
in eddies, more is stranded during flood time on the delta or in shal-
lows at the mouth ; but by far the greater part is swept out to sea,
there to be battered by the waves or carried by currents to perhaps
•distant shores. NordenskiokP- relates that driftwood in the form
of small branches, pieces of roots and whole trees with adhering
portions of roots and branches, occurs in such quantity at the bottom
of two well-protected coves near Port Dickson, that the seafarer
may provide a sufficient stock of fuel without difticult}'. The great
mass of driftwood carried down by the Yenesei floats out to sea.
Some of it is drifted by currents to Nova Zembla, the north coast of
Asia, Spitzbergen, perhaps to Greenland. Some of it becomes water-
soaked and sinks before reaching those shores. But not all goes to
sea, for some sinks in the river bed, upright as though rooted in the
sands. A bay off Port Dickson was found barred by a palisade of
driftwood.

"S. Powers, "Floating Islands," Pop. Sci. Monthly, Vol. LXXIX., igir,

PP- 30.3-307.

'■^A. E. Nordenskiold, "The Voyage of the Vega around Asia and
Europe," New York, 1882, pp. 152-154.

152

I9II-] STEVENSON— FORMATION OF COAL BEDS. 555

That the amount of driftwood accumulated on shores has been
estimated in exaggerated style is amply evident from Brooks's^^
observations. In the north and northwest part of Alaska from
Norton bay to the mouth of the Mackenzie river, the shore at one
time was abundantly supplied with driftwood. The Eskimos, who
have been using this wood for generations, are very economical in
the matter of fuel and, until the coming of the white man, the proba-
bilities are that the wood accumulated more rapidly than it was con-
sumed. This driftwood is brought down from the interior by the
larger rivers, whose banks are forested. The cutting of wood along
the banks of the Yukon has already diminished the contribution to
the northern Bering sea. The north Arctic coast, eastward from
Point Barrow, which is thinly populated by natives and rarely visited
by the white man, has some driftwood, but according to Franklin,
the quantity is unimportant along the coast visited by him ; the mate-
rial is brought down by the Mackenzie and is carried eastwardly by
a strong current. McClure found driftwood on the northeast coast
of Banks land, where it is often at a considerable distance above
sea level. Low** found that the prevailing winds and the force of
the waves have determined the accumulation of driftwood on the
shores of Hudson Bay. During great storms, the older, the lighter
portions of the mass are thrown to a considerable height above
mean tide.

The driftwood deposits on the northern side of Spitzbergen, on
Jan May en and Iceland are mentioned in most of the current text-
books of geology. Some of them, such as the Suturbrander of Ice-
land and the deposit on the New Siberia islands are clearly not drift-
wood, at least not the driftwood under consideration, as they contain
fruits and tender portions of plants and belong to the Tertiary. As
to the others, of undoubted modern origin, the common conception
is simply misconception. The descriptions, in many cases, would
lead one to suppose that the mass is closely packed and almost con-

"A. H. Brooks, "The Coal Resources of Alaska," Twenty-second Ann.
Rep. U. S. Geol. Survey, 1902, Part III., p. 570.

"A. P. Low, Ann. Rep. Geo). Surv. Canada, N. S., Vol. III., 1889, p. 33 J.

153

556 STEVENSON— FOR^IATIOX OF COAL BEDS. [November 3,

tinuous. Potonie*^ has given reproductions of two photographs, one
from Jan Mayen and the other by Nathorst from Amsterdam island.
The drift material is scattered irregularly, as one should expect, with
here and there a considerable pile. The fragments, some of which
are very large, are thoroughly battered — the whole resembling very
closely what one sees on the gravel flats of rivers subject to flood.

Crantz*" was among the first to describe the driftwood deposits
of Greenland and adjacent regions, and his statements have been
cited again and again, acquiring the increment which usually comes
with frequent repetition. In the driftwood on those shores he saw
many great trees, which had been torn out by the roots and which,
through driving and dashing amid the ice for many years, had been
deprived of bark and branches and had been bored by worms. A
small part of this debris consisted of willows, alders and birches
from bays in southern Greenland ; with these were aspens from some
more distant region ; but the predominant forms are pine and fir
with great abundance of a fine grained wood, with few branches,
which he took to be larch. With these is a reddish wood of agree-
able odor, resembling the Zirbel of the Alps. The grouping shows
that the trees came from a fertile but cool or alpine region.

The drift could not have come from the American coast at the
southwest as the current is contrary ; it must have come with the
icy current. It is most plentiful on the coast of Iceland and, on the
southwest side of Jan Mayen in X. L. 75°, there are two bays in
which there is so nnich wood, driven in by the ice, that a ship might
be loaded with it. He thinks the wood may have come from Siberia,
where pine and cedar abound, though it may have come from the
west coast of North America by way of Bering strait.

Crantz may be right or wrong in his suggestion respecting the
source of the material; that is unimportant. His description shows
that the mass, though considerable, is comparatively insignificant.
The accunuilation on the Jan Mayen bays, instead of being a closely

" H. Potonie, " Die Entstelnmg der Steinkolile uiid der Kaustobiolithe
iiberhaupt," Berlin, Funfte Aufl., iQio, p. 126; NatHrzinss.-JVochinschrift,
Vol. IV., Part 4-

*" D. Crantz, "The History of Greenland," I'-ng. Trans., London, 1820,
Vol. L, pp. 35-37.

154

iQii] STEVENSON— FORMATION OF COAL BEDS. 557

packed deposit, was merely enough to load a Danish merchantman
of one hundred years ago — say a vessel of 400 or 500 tons. The
description shows also that the wood had floated long ; it matters not
whether it came by the slow drift from Siberia or Norway to north-
ern Greenland and thence southward, or followed the north coast
eastward to Davis strait, it is certain that the voyage was very long
and the wood showed the efifects. This long continued buoyancy
of the wood is equally evident in the Gulf of Mexico, where one
finds the Mississippi drift wood stranded on the shores along hun-
dreds of miles.

In all extensive deposits of driftwood, the trees are battered,
stripped of leaves, bark and often of branches; they are scattered
on the strand or piled in irregular loose heaps, where, exposed to
the air, they decay; or if in more favorable conditions, the inter-
stices become filled with sediment, the trees become merely logs in
shale or sandstone, even their genus being unrecognizable except by
microscopic study of the structure.

The quantity of finely divided organic matter transported by
rivers is minute in comparison with that of inorganic. Pourtales^^
examined sediment from samples of Mississippi water collected at
Carrollton, Louisiana. The first series, taken in March during a
flood from the Red and Ohio rivers, yielded no matter of organic
origin aside from some spicules of sponges and rare vegetable fibers.
A second series, collected in June, during a Missouri flood giving the
most abundant sediment of the year, contained in water from the
surface some indistinct vegetable fibers and wood cells, but no re-
mains of vegetables were found in the other samples taken at various
depths. A third series, in August, contained a vegetable scale or a
leaf of moss; while a fourth series, in October, contained no organic
matter. A fifth series, collected in the following January, showed
on nearly all the filters minute black bodies which may have been
pollen or spores.

But the absolute quantity of organic matter carried out is con-
siderable. The " mud lumps " ofi^ the mouth of the Mississippi, are
masses of tough clay, occasionally forming islands of several acres,

■" L. F. Pourtales, in Humphreys and Abbot, Appendix 8, p. 651.

155

558 STEVENSON— FORMATION OF COAL BEDS. [November 3,

which rise 3 to 10 feet above the water and give off much inflam-
mable gas. They were studied by Sidell'*- for the Mississippi survey
of 1838 and by Humphreys and Abbot at a later time. Sidell be-
lieved that in outflow of the river the finest materials, organic matter
and silt, went farthest and, after deposition, were covered with
coarser materials. Decomposition of the organic matter generates
gas, which lifts the overlying deposits. According to Humphreys
and Abbot, the mud lumps are formed on the crests of bars and
their activity ceases when the gas is exhausted. In 1858, during
operations for removal of obstructions, some mud lumps on the bar
of Southwest pass were broken by an explosion of gunpowder.
Strong ebullition of gas continued over a wide area for 20 minutes
after the explosion and the surface of the bar, in a space, 100 feet
diameter, sank, assuming the form of an extinct crater. Hilgard*"
gives as composition of gas from one of the mud lumps, marsh gas,
86.20, carbon dioxide, 9.41, and nitrogen, 4.39, which closely resem-
bles the average composition of gas from swamps. Oxygen is absent.
Very little of the vegetable material is stranded on the banks of
rivers, comparatively little is deposited on the deltas. Most of the
great accunuilations in the Mississippi delta, supposed at one time to
be driftwood, have proved to be buried forests in place. Terrace
deposits along the Monongahela, in Pennsylvania and West Virginia,
contain only here and there a woody fragment in the mass of sand,
clay, gravel and blocks of rock. The same is true of terrace deposits
generally, away from the lines of abandoned curves. In this con-
nection. Brown's"" observations along the Amazon are instructive.
Long lines of cliffs, now on one side, now on the other, are composed
of bright-colored deposits, contrasting with the monotonous clay
banks of the river. The elevated plateau of these old river deposits,
as well as the alluvial plain, is covered with luxuriant forest. Ex-
cept a narrow strip along the bank, the whole plain is overflowed

"Humphreys and Abbot, op. cit., pp. 485, 486; W. H. Sidell, Ibid., Ap-
pendix A, p. 499.

^" E. W. Hilgard, "The Exceptional Nature of the Mississippi Delta,"
Science, N. S., Vol. XXIV., 1906, p. 865.

°'' C. B. Brown, " On the Ancient River Deposit of the Amazon," Q. J.
Geol. Soc, Vol. XXXV., 1879, pp. 763-777.

151)

■911.] STEVEXSOX— FORMATION OF COAL BEDS. 559

during the periodical floods. The chff crests are from loto i6o feet
above the floodmark and sections show white, yellow and red sands
with bluish or variegated clay beds. Ten feet of red clay was seen
at the top of one section, while in another are white clays resting on
bright red clays. The area studied by Brown is about 400 by 1,000
miles. Within this he saw four insignificant exhibitions of vegetable
matter in the deposits, which seem to have been laid down in an
estuary.

It is evident that very little of the drifted material is deposited
anywhere within the river region or immediately beyond ; the drift-
wood deposits on the northern shores, though vast in the aggregate,
clearly represent but a small part of the timber brought down by the
great northward flowing rivers ; the writer has followed the Gulf
Stream for more than 3,000 miles but he has rarely seen floating
logs ; in rhe central part of the so-called Sargasso sea of the north
Atlantic, he saw no floating timber and captains of steamships
familiar with that area have assured him that driftwood is of rare
occurrence ; the Orinoco brings down great numbers of trees which
should be caught by the westward current, but the writer, during
two voyages between Trinidad and Colon, saw not one. \Miat, then,
becomes of the vegetable material carried down by the rivers ?

Deep sea soundings in the Atlantic ocean give no answer to the
question. ^Material brought up by the trawl seems to be practically
free from vegetable matter. It has been suggested that the constant
" creep "' at great depths maintains the supply of oxygen, which
under the pressure would be greater than at the surface, so that
organic matter would be destroyed. \\'hether or not the explana-
tion be in this suggestion, it is certain that where dift'erent conditions
of movement and pressure exist, one finds an accumulation of vege-
table material on the ocean bottom. The observations by Agassiz^^
in the Gulf of Mexico and the Caribbean as well as in the Pacific
off the coast of ^Mexico are final in respect to this matter. His
statement is that

"A. Agassiz, "Three Cruises of the Blake," Bull. Mus. Conip. ZooL,
Vol. XIV., p. 291 ; " General Sketch of the Expedition of the Albatross,
1901," Vol. XXXIII., p. 12.

157

560 STEVENSON— FORMATION OF COAL BEDS. [November 3.

" While dredging to the leeward of the Caribbean islands, we could not
fail to notice the large accumulation of vegetable matter and of land debris
brought up from deep water many miles from the shore. It was not an un-
common thing to find at a depth of over one thousand fathoms, ten or
fifteen miles from land, masses of leaves, pieces of bamboo and sugar cane,
dead land shells and other land debris, undoubtedly blown out to sea by the
prevailing trade winds. We frequently found on the surface masses of
vegetation, more or less waterlogged and ready to sink."

The violent hurricanes of the Caribbean, as described by Maury,
must contribute very largely to the mass of vegetable material.
Agassiz found similar conditions at the bottom of the Pacific during
the cruise of the Albatross, when he was surprised at the distance to
which land-derived material had been carried. Along most of the
distance between Acapulco and the Galapagos islands as well as all
along the coast from Acapulco northward to within the Gulf of Cali-
fornia, there is a very sticky mud covering the bottom and inter-
fering seriously with the work of dredging. His description of con-
ditions between Acapulco and the Galapagos is

" Nearly everywhere along our second line of exploration, except on face
of the Galapagos slope, we trawled along a bottom either muddy or com-
posed of Globigerina ooze, more or less contaminated with terriginous
deposits and frequently covered with a great amount of decayed vegetable
matter. We scarcely made a trawl which did not bring up a considerable
amount of decayed vegetable matter and frequently logs, branches, twigs,
seeds, leaves, fruits, much as during our first cruise."

The conditions were similar along the continental coast. The
trawl was ordinarily well filled with mud along with the usual supply
of decayed vegetable matter. Observations of like character have
been made by others elsewhere in the Pacific.

In all probability, a great part of the vegetable matter swept out
to sea disappears by oxidation at the surface or in the depths ; but
in favorable localities another great part is deposited in fragmentary
condition with fine muds on the bottom, there eventually to form
beds of carbonaceous shale.

Conclusions. — The grouping of facts presented in the preceding
pages, proving shnilarity of conditions in all parts of the world,
seems to justify the following conclusions:

I. If torrents carry clear water, they produce little efifect on

158

191 1.] STEVENSON— FORMATION OF COAL BEDS. 561

either the rock over which they flow or the vegetation growing on
the floor or on the walls. If they carry sand, clay or even fine
gravel, vegetable growth on islands, formed by aggradation, resists
the flow and causes increased local deposit without material injury
to itself. Even fierce mountain torrents sweeping their load of very
coarse materials over a dejection cone do not clear the surface from
trees.

2. Water of rainfall has practically no ability to remove a cover
of living vegetation, even on steep declivities, except indirectly — as
by finding access to unconsolidated material below, which may be
rendered semi-fluid, so as to move down as a landslide. The heaviest
rainfall barely disturbs the cover of litter in a forest; that material
breaks the force of the falling drops, it absorbs much of the water,
it obstructs the formation of rivulets and protects itself as well as
the underlying soil from erosion. Forests are practically uninjured
by the heaviest rainfall ; even tiny plants, growing in clefts of rocks
are equally undisturbed. Rain does not remove the petty deposit
of soil on a projecting point of rock, if a tuft of grass has thrust
roots into it.

3. River floods in great lowland areas rise slowly, as is shown
by the floods of [Mississippi, Amazon, Orinoco, Nile and the rivers
of central Africa. In passing through forests, those floods lose
speed and become merely a quiet overflow* with sluggish movement,
so that they disturb neither the living growth nor the decomposed
litter on the surface. They move the loose dried twigs and leaves,
but even those in great part, are transported only a short distance,
unless swept into the stream from the bank. The main current
itself cannot uproot trees; it cannot even tear loose a floating tree
which has lodged against a sandbar directly in the line of strongest
flow ; but, unless the sandbar be washed away and the tree be set
free, that will remain as a " snag," to become more firmly fixed
during each succeeding flood. In most cases, the areas subject to
these vast floods are prepared beforehand by heavy rains, whereby
the humus cover is soaked and, so to say, cemented to resist the
moving water. A dense growth of vegetation forms in the channels
of tropical rivers and ofi'ers such resistance that even the mightiest

159

5G2 STEVENSON— FORMATION OF COAL BEDS. [November 3.

floods are checked as surely as though dammed by a mountam.
Logjams are not swept out by the greatest floods, though the accu-
mulation is merely superficial ; in spite of floods, they accumulate at
the upper end while decaying at the lower. If floating debris enter
a lake of moderate size, it finds its way directly to the outlet ; but if
the lake be large and disturbed by waves, the debris is scattered
along the shores. Finely divided organic matter carried out by
floods is in minute quantity compared with the mineral matter and
it is deposited along with the fine mud.

4. The trees as well as the humus swept out by floods were not
uprooted by the running water. Their presence in the current is
due to the undermining of banks composed of unconsolidated mate-
rial, so that trees, humus and the rest fall together into the water to
be carried away. The damage thus done is very small — the drift
carried by the lower Mississippi being the accumulation from the
soft banks of more than 20,000 miles of river, the length of tor-
rential and semi-torrential streams being neglected, as they contribute
an insignificant proportion of the mass. The quantity of driftwood
in all is unimportant, when one considers the area into which it is
swept. Comparatively little lodges on its way down the larger
streams and most of that is buried in muds as " towheads " or
" snags " or accumulates in rafts to disappear by rotting. A small
part is stranded on deltas, far less than has been supposed, for in
the Mississippi delta the deposits, supposed to be of driftwood, are
now known to be old swamps and forests buried in situ, ^tuch
finds its way to shores more or less distant where, after having been
for long time the plaything of winds and currents, it is cast in bat-
tered condition, scattered here in clumps or in individual pieces to
decay or to be buried in sands. But the greatest part floats until, in
half-rotted condition, after long exposure, it finds its way to the
depths of the sea, to litter the bottom in areas, 1,000 to 1,500 fathoms
below the surface, where, mingled with remains of marine animals,
it will become part of bituminous shales, with here and there a pot
of impure coal.

5. The conception that moving water, under any known or re-
corded conditions, can uproot forests and sweep oft' peat bogs from

160

'91 1-] STEVENSON— FORMATION OF COAL BEDS. 563

even moderately extensive areas is wholly without basis in fact.
One must regard it as originating in medieval descriptions of the
devastating force of the Xoachic deluge, which became an integral
part of religious and romantic literature, so that the conception was
accepted as a fundamental truth, needing neither investigation nor
proof.

The Phenomena of Peat Deposits.

Peat or turf is familiar to those living in the temperate zone.
It is an accumulation of vegetable matter undergoing special chem-
ical change because protected from atmospheric oxygen by an excess
of moisture. If one examine an old peat bog, he finds the surface
covered by plants of various kinds growing on more or less decayed
material. This, in its uppermost portion, is brown or yellowish
brown, but the tint deepens downward until in the ripe peat it is
almost black. At the top, one finds the vegetable structure distinct,
but downward that becomes more and more obscure until in the
mature peat it cannot be recognized by the unaided eye, and there
seems to be only a vegetable mud containing, at times, fragments of
slightly changed wood.

Peat-making Plants. — Sphagnum is regarded by many authors as
the all-important agent in production of peat ; and this supposed con-
dition has been utilized more than once to fortify arguments against
the suggestion that coal beds originated from growth in situ. The
prevalence of this misconception is strange, for evidence to the con-
trary has been presented in many works during the last centurv.

Darwin^- says that in the Chonos archipelago, S. L. 44° to 46°,
every piece of level ground is covered with Astilia pumata and
Donatia magcUanica, " which by their joint decay compose a thick
bed of elastic peat." In Tierra del Fuego, the former is the chief
agent. Fresh leaves appear constantly around the growing stem,
while the lower ones decay. Tracing a stem downward into the
peat, the old leaves can be seen in all stages of decomposition until
the whole has become blended into a confused mass. Every plant

" C. Darwin, " Journal of Researches,"' New York, 1846, Vol. II.,
pp. 24-26.

161

564 STEVENSON— FORMATION OF COAL BEDS. LNovember 3,

in the Falkland islands becomes converted into peat. He saw no
moss peat anywhere in South America. Thomson^^ notes that peat
in the Falkland islands is very different from that of northern Eu-
rope, cellular plants being almost wanting. It is formed for the
most part of roots, matted foliage and stems of Empetrum ruhrum,
a varietv of " crowberry " common on Scottish hills ; Myrtiis num-
mularia, a creeping myrtle ; Caltlia appcndiculata, a dwarf species of
water marigold ; with some sedges and sedge-like plants. The roots,
preserved almost unaltered, may be traced downward in the peat
for several feet, but finally all structure is obliterated and the whole
is reduced to an amorphous structureless mass. Mrs. Brassey's^*
description of accumulated decayed and decaying vegetation at Borja
bay in the Magellan region is in place here, as showing the origin of
peat from forest material.

" To penetrate far inland, however, was not so easy, owing to the dense-
ness of the vegetation. Large trees had fallen and rotting where they lay
under the influence of the humid atmosphere, had become the birthplace of
thousands of other trees, shrubs, mosses and lichens. In fact, in some
places, we might be said to be walking on the tops of the trees and first one
and then another of the party, found his feet slipping through into unknown
depths below."

But long prior to Darwin, Al. Brongniart^^ asserted that the
presence of Sphagnuiii palnstrc is not necessary to the formation of
peat. One finds on the banks of the Meuse, below Maestricht, some
peats containing only leaves of resinous trees. He contents himself
with the observation that all are agreed that, for formation of peat,
the essential condition is stagnant water, covering the surface con-
stantly and never completely dried up. Lesquereux^" defined peat
as a mass of woody plants whose fermentation and, consequently,
decomposition were retarded by the presence and the temperature

''C. Wyville Thomson, "The Atlantic." New York, 1878, Vol. II.. p. 185.

"Mrs. Brassey, "Around the World in the Yacht Sunbcaiii," New York,
1883, p. 128.

"Alex. Brongniart, " Traite elementaire de mineralogie," Paris. 1807,
Vol. II., p. 41.

^'^ L. Lesquereux, " Quelques recherches sur les marais tourbeux," Mem.
Soc. dcs Sci. Nat. Ncuchatcl, Vol. III., 1845, p. 26.

162

I9II] STEVEXSOX— FORMATION OF COAL BEDS. 565

of water. \'ogt,^" while giving pre-eminence to Sphagnum, notes
that under favorable circumstances any vegetable substance can be
converted into peat, for some peats are formed of grasses and reeds.
Heer^^ assigns to mosses only a subordinate part and asserts that
peat originates partly from mosses, partly from water-plants, from
swamp plants, especially from grasses and sedges, and partly from
woody plants. A. Winchell in i860 and Grand'Eury in 1882 made
the conditions equally clear, w^hile Friih^'-' showed that Sphagnum is
a late arrival in accunuilation of peat.

Peat in the Tropics. — The belief prevails that peat is not pro-
duced in the tropics. Jameson,''** long ago, asserted that peat is
peculiar to cold climates, but not wholly so, for Anderson had re-
ceived some from Sumatra. It is quite natural to find peaty sub-
stances in warm climates for peat at the bottom of a mountain is
more decomposed than that at the top ; that of southern England
more than that of north Scotland; that of France is more coalv than
that of England, while no peat is found in the French lowlands
except under cover. All of which shows that decomposition in-
creases toward warm climates, until, in the tropics, it is so rapid
that masses of peat cannot form.

Fruh^^ was unwilling to believe that true peat forms in the
tropics. He discusses a great number of reported occurrences in
tropical and sub-tropical areas. For him, the observations are in-
complete and his conclusions are that, so far as known, there is no
important deposit of true autochthonous peat in the lowlands of the
tropics ; that, within the tropics, formation of peat is in elevated
regions, where the climate is that of the temperate zone ; that the
supposed peat layers, bored through in the alluvium of great trop-
ic. Vogt, " Lehrbuch der Geologic," 2d Aufl., Braunschweig, 1854, Vol.
II., p. no.

°^ O. Heer, " Die Schieferkohlen von Utznach und Diirnten," Zurich,
1858, pp. 1-4.

^°J. J. Friih, " Ueber Torf und Dopplerit," Trogen, 1883.

*^R. Jameson, "An Outline of the Mineralogy of the Shetland Islands,
and of the Island of Arran," Edinburgh, 1798, pp. 151-153.

" J. J. Friih und C Schroter, " Die ]Moore der Schweiz," Bern, 1904,
pp. 134-143-

163

566 STEVENSON— FORMATION OF COAL BEDS. [November 3.

ical streams, are prevailingly allochthonous. In this last his refer-
ence is to the record cited by Lyell,^^ of a boring in the Ganges delta,
which passed through a deposit, having certainly the characteristics
of a peat bed. In view of what has been said on preceding pages
respecting the accumulation of drifted vegetable matter and of the
fact, that the great deposits in the Mississippi delta, formerly sup-
posed to be of drifted material, are of in situ origin, one is justified
in saying that the testimony of that and other borings cannot be
waived aside lightly by the mere assertion of allochthony. The onus
of proof is on the one making the assertion.

It is difficult to understand why the a priori reasoning that trop-
ical heat should prevent peat formation is thought so conclusive as
to make worthless the testimony, which would be accepted as prov-
ing the presence of peat in Michigan or north Germany. The con-
ditions of temperature during summer in much of the United States
are decidedly tropical ; yet peat accumulates. It is true that vege-
table matter exposed to moist air must decay more rapidly where
the temperature is constantly high than in the temperates, where the
hot period is of brief duration ; but that has nothing to do with the
matter under consideration, for one is concerned with decay of vege-
table matter protected from atmospheric action by a plentiful cover
of water. A priori^ one should expect to find peat accumulating in
those tropical regions, where the conditions are such as encourage
peat-making in the temperates — with only the difiference that, owing
to the continuous high temperature, complete decomposition should
be more rapid and the bog should have the vegetable mud near the
surface. But one is not dependent on a priori reasoning.

Harper''^ notes that it is an error to suppose that peat is confined
to cold climates, since high temperature does not prevent its forma-
tion if humidity and topography favor. Peat is abundant on the
very border of the tropics in Florida, where tropical temperature
prevails throughout the year. Sphagnuui does not occur south from

"^ C. Lyell, " Principles of Geology," Eleventh Ed., New York, 1872,
Vol. I., p. 476.

°*R. M. Harper, "Preliminary Report on the Peat Deposits of Florida,"
3d Ann. Rep. State Survey, iQio, pp. 214, 274, 287, 292.

164

1911-] STEVENSON— FORMATION OF COAL BEDS. 567

N. L. 29°, but the peat deposits within southern Florida, as far
south as lat. 25° 30', are of great thickness, one dense cypress swamp
showing 20 feet. The Everglades of Florida embrace about 7,000
square miles, which must be regarded as considerable. Even be-
tween lat. 30° and 31°, there are thick deposits in which Sphagnum
is wanting or very rare. Cypress, grasses, fern, myrtle make up
most of the vegetation and provide material for peat. The water
hyacinth, recently introduced into one of the rivers, is now a peat-
maker and, in some localities, the peat is composed almost wholly
of this plant.

The temperature conditions in the Bermudas are somewhat less
severe in summer than in southern Florida, for the summer heat
rarely exceeds 84° F. The southwest wind, blowing off the still
warm Gulf Stream, prevents low temperature and the humidity is
always high. On the main island there are two great swamps, one
of which has at least 50 feet of peat. The climate is such that
plants of Carboniferous type could grow well, for the banana thrives
while palms and the India rubber tree attain great size.

The literature bearing on tropical swamps is very limited. Those
swamps, often of vast extent and covered with dense forest, are
regarded, rightly or wrongly, as malarial to the last degree, so that
they do not invite close examination on the part of travellers. Yet,
even in the limited literature, one finds ample proof that, when the
necessary condition of topography and continuous moisture prevail,
peat does form.

Wall and Sawkins*^* estimate the swamp area of Trinidad at six
per cent. The long dry season is not favorable to the accumulation
of peaty materials ; yet the Nariva swamp, drained by streams flow-
ing 12 to 15 feet below the general level, has a black soil which after
desiccation at 300° F. still yielded 35 per cent, of organic matter.
Hartt°^ found peat in the state of Sao Salvador, Brazil, S. L. 10°.
He states distinctly that he found peat. " A quarter of a mile south

"^ G. P. Wall and J. G. Savvkins, " Geology of Trinidad," London, i860,
pp. 62, 63.

"^ C. F. Hartt, " Geology and Physical Geology of Brazil," Boston, 1870,
pp. 365, 509-

PROC. AMER. PHIL. SOC, I.. 202 I, I., PRINTED NOV. 1 6, I9II.

J 65

568 STEVENSON— FORMATION OF COAL BEDS. [November 3,

of the Imbugahi is such a grass-covered area, and here excavations
by the side of the raih'oad show that a bed of peat has accumulated,
which is two feet thick in some places." It is difficult to understand
on what grounds a recent writer feels justified in asserting that this
is probabh' bituminous shale. Hartt knew peat and he knew bitu-
minous shale when he saw them. On the authority of the engineer
who constructed the railroad in Sao Paulo, Hartt states that near
Tumanduathy the land spreads out between the hills, level as a lake
and about two miles wide, covered with deep 'layers of black soil
" fibrous and woody like peat." The railroad was built over the
surface of this bog, but no eft'ort was made to determine the thick-
ness of the deposit. •

Mrs. Agassiz, cited in another connection, gives evidence respect-
ing present conditions in Brazil. Kuntzc''" has described the for-
ested swamps on the divide between the Amazon and the Paraguay.
High water makes ponds on the broad alluvial plain, in which Ponte-
deria and other plants settle. The ponds become filled with silt and
humus and a swamp flora, rich in palms, takes possession of the sur-
face. The Lourenqo or Cuyaba river, rising in the low divide,
unites with the Paraguay at about S. L. 18°. This river, for about
three degrees of latitude, flows through the vast wooded Guatos
swamp, which Kuntze thinks is, at least in part, a floating bog. He
gives no estimate of thickness, but his brief statement leaves no
doubt that the mass is very great. The material is true peat, for in
another part of his work he speaks of the fragments of peat occa-
sionally torn off from the mass. The invasion of streams by grasses
is rapid and complete throughout this region. Kuntze notes this.
Morong,''' in speaking of his attempt to reach the head of Pilcomayo
river in S. L. 22°, says that his progress was stopped in a lagoon, 400
miles from the Paraguay river, by a dense growth of grasses and
weeds, one species of the former attaining the height of 5 meters.

The great accumulations in the lowlands of Nicaragua and Costa
Rica have been mentioned by several authors and the writer knows

"" O. Kuntze, " Gcogenctische Beitriige," Leipzig, 1895, pp. 5, 67, 70.
«'T. Morong, Ann. N. Y. Acad. Sci., Vol. VII., 1892, pp. 45, 260.

1G()

19".] STEVEXSOX— FORMATIOX OF COAL BEDS. 569

that great swamps with notable depth of vegetable mud abound on
the isthmus of Panama.

Livingstone, Cameron and others, already cited, have given abun-
dant evidence that peaty accumulations are numerous and extensive
in the wet regions of interior Africa. Lugard,*''* in describing the
region near Albert Edward lake, refers to interminable river swamps
and bottomless quagmires, choked with papyrus, which abound in
Uganda and Ungoro and cease below about half a degree south from
the equator. Miss Kingsley®^ says that she encountered three types
of bog in west Africa. The broad deep bog was the least difficult,
as it makes a break in the forest, and the sun's heat bakes a crust
over it, on which one may go — if he go quickly; the shallow, knee-
or waist-deep bog is little more difficult as one can wade through it ;
but the deep narrow bog, so shaded that the sun cannot form a crust
over it, is the most abundant and the most difficult. " These re-
quired great care and took up a great deal of time. Whichever of
us happened to be at the head of his party, when we struck one of
these, used to go down into the black, batter-like ooze and trv to
find a ford, going on into it until the slime was up to the chin."

Chevalier"" has described an interesting type of peat formation
observed in an extended area between the Gulf of Guinea and the
sources of the Niger, X. L. 5° to 9°. This great region has many
granitic peaks rising to 1,200 or 1,400 meters, but in great part it is
a peneplain, 200 to 400 meters above sea level. The southern por-
tion is covered with a dense forest but the northern portion is a
savannah with only scattered trees and shrubs. The whole region
would be naked rock, were it not for the role played by a sedge,
Eriosponi /'/Vo.^a Benth., which at times covers the rocks to the exclu-
sion of all other forms. It attaches itself to granite and gneiss; the
seeds germinate in minute fissures and the roots spread in clusters
between thin plates of the rock, altered or decomposed bv atmos-
pheric action. When the thin plate of rock has been worn away

'' F. D. Lugard, Scottish Geog. Mag., Vol. VIII. , 1892, pp. 636-639.

°° M. W. Kingslc)-, "Travels on the Western Coast of Equatorial Afr'ca,"
Scott. Geog. Mag., Vol. XII., 1896, pp. 1 19-120.

™ A. Chevalier, " Les tourbieres de rocher de TAf rique tropicale," C. R.,
Vol. 149. 1909, pp. 134-136.

167

670 STEVENSON— FORMATION OF COAL BEDS. [November 3,

by water, heat or the activity of the plant, this is ready to resist the
rains and winds, for its adhesion is complete on the steepest slopes.

After spreading for sometime, the Eriospora lifts its rhizomas
into the air and sets off branches, each terminated by a bouquet of
grass-like leaves, and each year, before the rains, abundant rosettes
of leaves and flowering twigs are developed at the end of these rhi-
zomas. At the beginning of the dry season, these leaves wither and
soon afterward they are consumed by fires lightedby men or perhaps
by lightning; only the bases of the leaves remain; blackened, half-
carbonized, this coat thickens around the rhizoma. The growth of
the Eriospora tufts is apparently very slow, but, as they may live
for several centuries, they attain notable dimensions. On the border
of the virgin forest, some were seen more than a meter high and
half a meter thick at the base. The stem divides midway into ver-
tical branches, themselves dividing, the last division having a diam-
eter of 2 to 3 centimeters.

The tufts are not always in contact, there being at times an inter-
val of even 50 meters, but in these intervals on gentle slopes, one
finds a fibrous network, very humic, constituting a veritable bed of
peat, 5 to 30 centimeters thick. This peat is formed not only of
roots and rhizomas, but also of young colonies of Eriospora^ killed
soon after origin by fire or by lack of light. True mosses appear at
high altitudes. On the humid flank of Mount Momry, Chevalier
found a Sphaguum at 850 to 900 meters above sea level. The Erio-
spora peat covers tens of thousands of hectares in French west
Africa. The condition described by Chevalier is not wholly unfa-
miliar in the temperates, where mosses and other plants cover irreg-
ular rocky surfaces and form a coating of peat at times several inches
thick. This is seen frequently in the southern Appalachians. It is
the Rohhumus or Trockentorf of the Germans.

It was reserved for Potonie'^ to present the final evidence. Find-
ing no available literature giving details respecting moorformation
in the tropics, he applied to Koordes, botanist of the Dutch expe-
dition across Sumatra in 1891. Koordes informed him that in old

"11. Potonie, "Die Entstehung der Steinkolile iind der Kaustobiolitlie
iiljciiiaupt," 5th Aufl., Berlin, 1910, pp. 152-160.

168

I9I1.] STEVENSON— FORMATION OF COAL BEDS. 571

Javan and Sumatran forests, where hard woods grow, fallen trees,
many decades old, lie in great numbers and are still in good condi-
tion for export. Termites and fungi are effective agents for de-
struction of wood in the tropics, but the moisture is almost equally
effective in preventing the decay. During the Sumatra expedition,
Koordes saw a great, always green Flachmoor, with a 30-meters
high mixed forest, extending along the Kampar river at more than
90 kilometers from the coast. As Koordes had made no close study,
definitive evidence was wanting to prove that this moor had a true
peat floor. But Larive made the necessary sounding at Potonie's
reouest and discovered that the peat in this tropical moor is 9 meters
thick.

Examination with the microscope proved the presence of pheno-
gams ; spores or pollen ; occasional brown threads belonging possibly
to fungi ; some resin-like bodies, etc. The high content of silica in
the ash explains absence of diatoms in the microscopic preparations.
Chemically, the material is a true peat and German experts pro-
nounced it a good fuel. The ash in the dry material is 6.39 per cent,
while good north German Flachmoor peat has 5 to 7 per cent. The
ash of the Sumatran peat contains 74 per cent, of silica.

Koordes estimated the area of the freshwater swamp on the left
bank of the Kampar at 80,000 hectares. At both camps within this
swamp, the water was stagnant, dark brown and slightly astringent.
Walking over the swamp was possible only because roots of trees
covered the surface with a dense network. The character of the
growth, as shown in Fig. 52 of Potonie's work, is a clear instance
of adaptation such as is seen in the Taxodium of the southern United
States ; for the roots are widespread horizontally just below the
surface, uniting into " broom-shaped air roots " and " asparagus-
shaped pneumatophores." The trees of the forest are mostly ever-
greens, 25 to 30 meters high and closely set. The underbrush con-
sists, for the most part, of the same species but its growth is slow,
owing to the dense shade. The forms are all dicotyledonous and the
flora is wholly of inland type. Grasses, sedges and mosses are prac-
tically wanting; it is a forest moor. The stagnant pools, poor in

169

572 STEVENSON— FORMATION OF COAL BEDS. [November 3,

phenogams because of the dense shade, are comparatively rich in
confcrvae.

It is sufficiently evident that there is nothing in tropical condi-
tions which would prevent the accumulation of peat. Where there
is a long dry season, the vegetable matter is exposed as is that in
the ordinary upland forest in the temperate regions. The accumu-
lation of the humus cover advances rapidly for a time but at length
the waste by oxidation about balances the additions, so that the thick-
ness does not increase, though the trees shed a greater quantity each
year. But in a lowland area where the moisture is great, the chem-
ical changes are modified, the loss is diminished and increased supply
brings about increased accumulation. Swamps arise, when from any
cause the drainage is impeded. Even along the flow of small springs,
peat forms when the water is held back from any cause. On exten-
sive areas, such as the coastal plain on the Atlantic side of the
United States or the delta of a river like the Mississippi, where at
best the drainage is imperfect, the streams being sluggish and often
serpentine, the drainage has been hindered still further by vegeta-
tion, the moist area was enlarged and swamps of vast extent origi-
nated in post-glacial times. The important condition is the constant
supply of water ; the drainage must be impeded on the surface
and through the bed. In the northern part of the United States
probably the greater part of the swamps rest on an impervious bed
of glacial clay, an underclay ; but it is not necessary that the imme-
diately underlying bed be of normally impervious material, for many
large swamps have a floor of fine sand.

Harper"- penetrated 10 or 12 miles into the Okefinokee swamp
of southern Georgia and discovered that the material on which the
peat rests is a few feet of Columbia sand overlying the clay, loam
or coarse sand of the Grand Gulf formation (Lower Miocene or
Upper Oligocenc). In some places a "hard pan," colored by vege-
table matter and cemented by iron underlies the sand. Sanford'^

"R. M. Harper, "Okefinokee Swamp," Pop. Sci. Month., Vol. LXXIV.,
TQog, p. 596.

" S. Sanford. "Topography and Geology of Southern Florida," 26. Ann.
Rep. Gcol. Survey of Florida, 1909, P- I93-

170

'911] STEVENSON— FORMATION OF COAL BEDS. 573

reports that the peat of the Everglades in southern Florida rests on
sand, rock or marl. Grisebach, cited by Friih, endeavored to ex-
plain this apparently anomalous condition for north Germany by
the suggestion, that, in very wet years, peat may have been formed
in that region even on sands and, being itself practically impermea-
ble, it may have prepared the way for a Hochmoor. Be that as it
may, the fact remains that a swamp may begin on an apparently
permeable surface; the Everglades are at little above sea level, but
Okefinokee is 50 miles from the ocean and 115 feet above mean
tide — and its mucky peat contains 85 per cent, of combustible mate-
rial. In this latter case, one must believe that the underlying sand
is not far from an impermeable stratum and that it is saturated with
moisture or that by absorption of humic acid the sand itself has
been rendered impermeable.

Peat and Peaty Materials. — Russell'* describes the Alaskan tun-
dra as a swampy, moderately level country having a cover of mosses
and lichens with some ferns and many small flowering plants. Below
this dense carpet of vegetation is dark humus. Ponds and lakelets
abound, surrounded by banks of moss, and occasionally one finds
groves of alders and dwarf willows on their borders. The under-
lying black humus shows few indications of its vegetable origin. It
is 2 feet thick at St. Michaels but is 12 feet at a mile farther east.
He saw 15 feet on the Yukon and a depth of 150 to 300 feet is
assigned to it at the head of Kotzebue sound. The flora of the
tundra is essentially cryptogamic, but two species of Equisctum
flourish with rank luxuriance in great spaces along the Yukon. So
vast is this accumulation, in both area and thickness, that Russell
ventures to suggest that some coal seams may have had similar
origin. If the tundra coast of Alaska should subside, its peat would
be covered with sediments and be ready for transformation into lig-
nite or coal. Its associated plants and animals would indicate the
climatic conditions, but the overlying sanastone and shale might con-
tain leaves and tree trunks, floated in bv rivers from warmer regions.

But where the swamp is forested, especially if the wood resist

'* I. C. Russell, "Notes on the Surface Geology of Alaska," Bull. Geol.
Soc. Amer., Vol. I., 1890, pp. 125-128.

171

674 STEVENSON— FORMATION OF COAL BEDS. [November 3,

rapid decay, the change of that material may advance so slowly that
long after the softer parts have been reduced to pulp, the more com-
pact materials may remain almost unchanged. The white cedar logs
in the New Jersey swamps are so well preserved in many localities
as to be serviceable in manufactures, while the thick peat of many
swamps in Florida is without commercial value, because it is crowded
witli cypress stumps and fallen stems. But decay occurs in the
softer woods, so that, as v. Giimbel''^ relates, flattened trunks are
found even at a depth of only a meter in loose peat. The flattening
was due to rotting, not to pressure.

The newer peat shows distinct felting and Lesquereux'" states
that this condition is marked even when decomposition is far
advanced. In peats formed above the original water-plane, the
"emerged peats" of tliat author, the layers are characteristic, one
inch thick at the top but decreasing downward to less than one eighth
of an inch. While the older or ripe peat shows no trace of organic
structure to the unaided eye, the microscope proves that it is com-
posed of fragments of plants embedded in an amorphous material
consisting of humic or ulmic acid, or a mixture of those acids and
their salts. He observed that, whenever the growth of the peat was
checked by dryness or other causes,

" tlic upper surface of the peat heconies crusted, Iiarclened and transformed
into a thin coating, quite impervious to tlie entrance of any kind of foreign
matter : and it is upon this hard upper crust that the boggy humus forms ;
or wherever the land becomes resubmerged, a new peat vegetation begins.
In which case, such- a crust remains as a parting hiyer l)etween two beds of
peat, like tlie well known clay partings between two coal benches."

V. riiimbel, in the work just cited, asserts that the minute frag-
ments of plants are not only intimately mingled and felted but also,
in the denser portions, are bomul together and more or less cemented
by a luuinis-like substance, which is soluble in a dilute solution of
caustic potash. Peat, treated with this reagent and afterwards dried.

" C. W. V. Giimbel, " Beitriige zur Kenntniss der Texturverhaltnisse der
Mineralkohlen," Site. Berich. d. k. bayer. Akad. d. Wisscnschaften. Math-
Phys. KL, 1883, p. 126.

'"' L. Lesqucrenx, 2d Geo). Surv. of Pennsylvania, Ann. Rep. for 1885.
p. 118.

172

'911] STEVENSON— FORMATION OF COAL BEDS. 575

frequently falls to powder, v. Giimbel found also, in many peats,
deep black coaly parts of plants as small fibers, a form which he
terms Torfifaserkohle and regards as a thoroughly characteristic type.

Peat always contains much water, often 95 per cent., when freshly
removed ; but a great part of this evaporates on exposure, there
remaining in the air-dried material from 10 to 30 per cent., the denser
peat retaining the larger quantity. When first taken out, it is plastic
but after thorough drying the plasticity is lost. Peat is very porous ;
V. Giimbel subjected Sphagnum peat to a vertical pressure of 6,000
atmospheres and reduced 100 centimeters to 17.7. The compressed
material was apparently homogeneous, the streak was lustrous and
lamination was distinct on the fractured surface. The reduction
was due wholly to compression, obliteration of the pores, for, when
moistened with water, the mass swelled to practically the original
bulk. This condition, however, may not be constant. The writer
has some briquetted peat, made under great pressure and moderate
temperature, which has no tendency to swell when moistened. It
has lost all plasticity and in sixteen years it has shown no change on
the brilliant surface at each end.

Peat, then, consists, aside from introduced sand, clay or calca-
reous materials, of more or less changed plant tissues, whose organic
texture is still recognizable, and of an enclosing substance derived
from complete decomposition of plant tissues, which is originally
soluble in water but which, on drying or perhaps on oxidation,
becomes insoluble.

Fuel peat has from i to 25 per cent, of ash. The purest peats
contain less mineral matter than is found in the plants whence they
are derived ; while on the other hand a peat deposit may pass from
pure peat into'carbonaceous mud and thence into muds almost wholly
W'ithout trace of carbon. Mills and Rowan'^ have given ultimate
analyses of surface and dense peats from two localities in Ireland,
which represent the extremes of high grade fuel.
In each case, the ash is excluded in calculating the other constituents.
The same authors give tw^enty-seven analyses of the ash found in

" E. J. Mills and F. J. Rowan, " Chemical Technology," Philadelphia,
1889, pp. 15-20.

173

576 STEVENSON— FORMATION OF COAL BEDS. [November 3.

different fuel peats from Ireland, which show, as one should expect,
extreme variations, due to local conditions. Potash and soda are in
small proportion, varying from 0.146 to 1.667 of potash and from
0.446 to 2.883 of soda, the greater quantity being in the dense peat.
Phosphoric acid is present in all but rarely exceeds 2 per cent.,
whereas sulphuric acid varies from 10 to 44 per cent. Hydrochloric
acid is present in small proportion, but approximately that required
by the soda. Lime and magnesia are always present, in some cases
the former makes up nearly one half of the ash and in others the
latter is one sixth. Ferric oxide varies from 6 to 30 per cent.
Silica occurs as sand or as soluble silica and alumina is always pres-
ent, though at times in small quantity. The ash in the samples
analyzed varies from 1.120 to 7.898.

I . H. O. N, Ash.

1. Surface, Phillipstown 58.69 6.97 32.88 141 1.99

2. Surface, Wood of Allen .. 59.92 6.61 32.20 1.25 2.74

3. Dense, Phillipstown 6047 6.09 32.54 0.88 3.30

4. Dense, Wood of Allen 61.02 5.77 32.40 0.80 7.89

The content of alkalies rarely exceeds 4 per cent, of the ash in
New Jersey peats and ordinarily it is less than one and a half per
cent. ; but calcium carbonate and sulphate are always present in
notable quantity, making up from 20 to 30 per cent, of the ash.'^^

Julien'"-* has given a synopsis of the available information respect-
ing the proximate composition of peat. The various organic con-
stituents seem to be of rather indefinite character and their study is
attended with serious difficulty. Julien cites an analysis from Her-
mann, giving composition of a peat obtained near Moscow :

Muck-carlion, nitrolin, plant remains 77.8

Humic acid 17.0

Humus extract 4.0

Ammonia 0.25

Crenic acids Trace

Ash 1 .25

" W. E. McCourt, " A Report on the Peat Deposits of Northern New
Jersey," Ann. Rep. Geol. Surv. of New Jersey for 1905, p. 227.

"A. A. Julien, "On the Geological Action of the Ilumus Acids," Proc.
A. A. A. S. for 1879, pp. 314-324, 329, 331. 353-

174

1911.] STEVENSON— FORMATION OF COAL BEDS. 577

But in peat from another locality, the process of change was
dififerent :

Muck-carbon, etc 80.0

Apocrenic acids 17.0

Crenic acids i .0

Ash 2.0

Julien notes the difference in ash between peat and the plants
whence it is derived. Sphagnum has from 3 to 4 per cent, and the
peat varies from i to 25 per cent. Vohl found only 1.25 per cent,
of ash in a Hochmoor or Sphagmon peat. In the ash of living
plants he found 20 per cent, of alkalies and 42 per cent, of silica, but
only 3 to 4 per cent, of each in the peat or in the soil. On the other
hand, there was concentration of alumina, ferric oxide and calcium
carbonate as well as of phosphoric and sulphuric acids. Pyrite occa-
sionally abounds in peat and its decomposition gives a basic ferric
sulphate to the bog iron ores.

Nitrogen is always present in peat, sometimes as much as 3 per
cent. ]\Iany suggestions have been made to explain its occurrence ;
but Julien thinks that most probably it has been derived from animals
living in the peat or in the soil. The vast number of insect cases
found in peat bogs is well known and Scudder has proved that
insects were very abundant in the coal period. The nitrogen content
is due very largely to the exuviae of insects, and its frequent concen-
tration in the lower layers of bogs may be due to the survival of
those exuviae as chitin.

In the humus one finds as inert substances, nitrolin (rotten wood)
and humin. which is black and forms the chief constituent of humus ;
but it is so mingled with nitrolin that its exact composition cannot
be determined. Mulder studied humus and humic acid from the
black peat of the Haarlem sea ; he obtained ulmic acid from rotten
wood as well as from the light brown Frisian peat. The formulas
of the several acids obtained seemed to be

Humic acid C^oHnOe

Geic acid C20H12O7

Ulmic acid CmHuOo

Stern, however, thought humic and ulmic acids isomeric, with the

175

578 STEVENSON— FORMATION OF COAL BEDS. [November 3.

formula C04H1SO9, while Ditmer thought them the same thing, the
latter being produced by drying the former.

Humic acid is a colloid and is not absorbed by plants, though its
oxidized product, crenic acid, seems to be taken up. Humic acid is
very slightly soluble in water at 6° C. ; if dried at 120° C. it is much
less soluble and if completely dried at a high temperature it is insol-
uble. Its alkaline salts are readily soluble but those with alkaline
earths and metallic oxides are insoluble or nearly so in water, though
readily in aqueous alkaline solutions. Calcium humate dissolves in
3,125 parts of water and ferric humate in 5,000 parts, but these form
soluble double salts with ammonia. Ulmic and humic acids are
rarely free except in bogs. A noteworthy property of humic acid
is that, as a colloid, it renders sand impermeable to water.

These feeble acids yield others upon oxidation. Humic gives
crenic, which is present in all waters, in rotten wood, in peat and in
cultivated soil. Julien has found it, as well as its oxidized product,
apocrenic, in American peat. Crenic acid, pale yellow and trans-
parent, is readily soluble in water ; in drying, it becomes opaque and
blackens when exposed to the light. Alkaline crenates are very
soluble but the calcareous salts are only slightly soluble. Those of
iron and aluminium are insoluble, but, according to Bischoff, the
iron salt is soluble in ammonia, so that it may be dissolved in the
presence of decaying nitrogenous substances. The apocrenates have
same distribution as the crenates but they are less soluble. These
organic acids bleach clays and have solvent effect on silica ; the most
efficient being the brown or ulmic constituents.

Liebig,^" writing soon after Mulder published the results of his
investigations, stated that a solution of caustic potash blackens in
contact with vegetable mould. Dilute sulphuric acid precipitates
from the solution a light, flocculent brown or black substance which
absorbs oxygen rapidly. After drying it is not soluble in water.
Cold water dissolves only one ten-thousandth of its weight from
vegetable mould and the dissolved material is chiefly salts ; but boil-
ing water extracts several substances, yellow or yellow-brown. On

*"'J. Liebig, "Chemistry in its Application to Agriculture and Physiology,''
Philadelphia, 1843, pp. 112, 113.

176

191 1] STEVENSON— FORMATION OF COAL BEDS. 579

exposure, the solution becomes darker and a flocculent deposit is
produced. If the yellowish solution be evaporated to dryness and
the residue be heated to redness, this becomes black and, when treated
with water, yields potassium carbonate. Evidently, boiling water
extracts a substance which owes its solubility to alkaline salts con-
tained in plants. Leibig says, on authority of Sprengel, that humic
acid becomes insoluble when dried in air or when frozen in moist
condition.

Hunt^^ has remarked that organic matters in solution acting on
insoluble peroxide of iron form the protoxide, which is soluble in
carbonic acid and in excess of the organic (acid) matter. In this
way, great quantities of iron may be removed and white clay or sand-
stone may be produced. The iron salts become oxidized and go
down as hydrated peroxide. Manganese deposits are formed in
similar fashion. He is inclined to believe that hydrated alumina
may originate in the same way. Organic matter dissolved by sur-
face waters reduces sulphates to sulphides and these, decomposed
in turn by carbonic acid, yield alkaline and earthy carbonates as well
as hydrogen sulphide.

One finds in bogs some types of peat to which the descriptions
thus far given do not apply. Examined in detail, these in some
cases suggest original differences due to mode of accumulation or to
character of material, while in others they appear to be due to sec-
ondary processes.

Long ago, Caspary described the Lebertorf obtained at Purpes-
seln, near Gumbinnen in east Prussia. This material was studied
very carefully by v. Giimbel.*- his specimens being from the type
locality. The deposit is 5 feet thick and at 10 feet below the sur-
face. When damp, it is liver-brown in color and dense, but when
dry it divides into paper-like laminae. Under the microscope it
proves to be composed of very fragmentary parts of plants within
a felt-like, flocky mass, in which are insects, recognizable grass and
moss, scattered black wood cells, many spores and an immense quan-

*' T. Sterry Hunt, " Chemical and Geological Essays," Boston, 1875, pp.

97-99-

''^ C. W. V. Giimbel, op. cif.. pp. 131, 132, 133.

177

580 STEVENSON— FORMATION OF COAL BEDS. [November 3.

tity of pollen. Two specimens from other localities agree in that
the cross-section shows a comparatively dense mass of boghead-like
material, deep brown in color. One contains well preserved remains
of leaves and other organs and the other contains some freshwater
mollusks. The granular, felt-like mass, treated with reagents, breaks
up and then one sees fragments of woody material, seeds, mosses,
and above all pollen grains, several thousands to the cubic milli-
meter. This substance bears remarkable resemblance to cannel.

Blattertorf, so named from its foliated structure, is closely allied
toLebertorf. v. Giimbel has described a specimen from thekurishen
lowland south from Nidden. This mass, in extraordinarily thin
lamina?, is composed of numerous bright lamellae alternating with
dull layers, recalling by their luster, pitch and glance coals. The
bright material comes from ribs and the harder parts of plants, the
grass leaves, which compose the chief mass. Along with those are
bits of moss, bast fibers, etc., in the felt-like mass, as well as an
astonishing number of pollen granules.

The results of Friih's'^^ studies were published in the same year
with those of v. Giimbel. His conclusions respecting the composi-
tion of Lebertorf differ somewhat from those reached by v. Giimbel.
One rarely finds in ordinary peat any remains of freshwater algae.
But Friih finds that those algiT do not tlecompose so readily as one
might imagine ; yet in the ordinary peat they are only rare and acces-
sory constituents, never occurring in such quantity as to be impor-
tant elements. At the same time there are types of which they are
essential constituents.

The Febertorf, found in ponds within Prussia, as the basis of
the Rasenmoor at Purpesseln and as basis of a Hochmoor at Gum-
binnen, is a liver-brown gelatinous mass. That from Jakobau, in
west Prussia, consists chiefly of algae, there being more than 60 spe-
cies of Chroococcaceae, Plydrodictea? and Diatomacere, with which
are found indefinite remains of mosses along with pollen of Pinns
and Coryhis. The Torfschiefer of E. Geinitz from Gustrow has a
very similar composition. The typical Pebertorf from Purpesseln
has recognizable colonies of Macrocystis, while that from Niederwyl

"J. J. I'Viili, " Ue1)cr Torf und Dopplcrit," Trogen, 1883. p. 20.

178

I9II.] STEVENSON— FORMATION OF COAL BEDS. 581

in Thurgau shows algae as the chief constituents, with pollen and
chitin remains, all felted and embedded in a gelatin-like mass. These
Lebertorfs originated in quiet waters or on damp soil, through con-
tinuous deposition of gelatinous algae.

Lebertorf is the same with Faulschlamm or Sapropel of Potonie,**
an accumulation of stagnant water organisms, animals as well as
plants, a formation characteristic of pools in swamps. The fresh-
water algse multiply with such rapidity that eventually a great mass
may be deposited. Potonie says that there are lakes in south Ger-
many so filled with Sapropel that they cannot be navigated. Cas-
pary, cited by Friih, conceives that there is no peat-filled lake, on
whose bottom this material does not exist. He found it about 9
meters thick at one locality. Friih has given a synopsis in his later
work of studies by the students of northern Europe which show the
wide distribution of this material. But Lebertorf or Sapropel, so
closely resembling cannel in appearance, is not the mass of peat; it
is wholly local, originating in open ponds or lakes. The gelatinous
algse are of comparatively rare occurrence in true peat, which owes
its origin to plants of wholly different type.

The substance, known as Dopplerite, was described by Haidinger
in 185 1 and was studied in great detail by v. Giimbel in 1858. Its
similarity, in some respects, to coal led the latter author to give it
the name of Torfpechkohle. It occurs at many localities, so many
that it may be regarded as a normal constituent of peat. The first
reference to material of this type in America is in a paper by Fair-
child,®^ who obtained some from a bog at Scranton, Pennsylvania.
It is described as bright, resembling a firm but brittle jelly and as
occurring in branching masses through the ripe or older peat. In
drying, it shrinks more than the peat and the color changes from
yellowish brown to almost black, finally becoming brown. In struc-
ture it resembles coal.

Julien,**' discussing Fairchild's communication, asserted that the
physical features of the substance, as described, are those of apo-

^ H. Potonie, " Die Entstehung," etc., p. 20.

'"H. L. Fairchild, Trans. N. Y. Acad. ScL. Vol. I., 1881. p. 73.

"A. A. Julien, Trans. N. Y. Acad. Sci., Vol. I., 1881, pp. 75, 76.

179

582 STEVENSON— FORMATION OF COAL BEDS. [November 3,

crenic, humic and other organic acids. He was inclined to believe
that this material had been produced by the leaching out of soluble
salts of organic acids, in part crenates, from the upper part of the
bog and their concentration in the denser portions below, where they
filled cavities in the peat. The rapid change in color is not the
trifling change due to drying, but is a characteristic reaction of
crenic acid, due to oxidation and to partial change into apocrenic
acid — a feature observed in the acid and in its salts, both in nature
and in the laboratory.

Lewis'^' described the material with more detail. It occurred in
swamp muck underlying 8 to 10 feet of peat. Near the bottom and
confined wholly to the muck, are irregular veins filled with a black
jelly-like elastic substance, in quantity varying from mere stains to
streaks, two or three inches wide. When first taken out it is jelly-
like, with conchoidal fracture, but on exposure it becomes tougher
and more elastic. Under the glass it is brownish red and nearly
homogeneous. It is tasteless and odorless, burning slowly and with-
out flame, when fresh. It is insoluble in water, alcohol and ether
but is dissolved by caustic potash. Completely dried, it is brittle
and coal-like, resembling jet ; it burns with a clear yellow flame and
no longer softens in water. In composition, it difl^ers from the
typical dopplerite in that it contains little more than half as much
carbon and very much more oxygen.

Kaufmann, cited by Lewis, regarded dopplerite as a mixture of
humus acids and believed that the portion of peat, soluble in caustic
potash, is identical with dopplerite. Compact peat contains minute
black particles of dopplerite. Peat is merely a mixture of partly
decomposed plants with dopplerite, the latter being a homogeneous
peat in which all organisms have been decomposed. Kaufmann
found that the proportion of material soluble in caustic potash in-
creases with age, a recent peat giving from 25 to 30 per cent., while
an old compact peat gave "JJ per cent. But in coals, the proportion
decreases, from a diluvial brown coal, with yj per cent., to anthracite
in which no portion is soluble. His conception is that, in the forma-

" H. C. Lewis, " On a New Substance Resembling Dopplerite, from a
Peat Bog at Scranton," Proc. Amer. Phil. Soc. Vol. XX., 1881, p. 112.

180

19".] STEVENSON— FORMATION OF COAL BEDS. 583

tion of coal from peat, the first step is the formation of dopplerite
and the second is a gradual transformation of the latter into a mate-
rial less soluble in alkalies and richer in carbon. The peculiarities
of the Scranton mineral, its low percentage of carbon and its mode
of combustion led Lewis to suggest that it may represent an earlier
stage in transformation than that of dopplerite.

V. Giimbeh** in giving the results of his later studies, described
dopplerite as a yellow brown homogeneous mass without trace of
organic structure and enclosing only separated parts of plants. It
burns with a sooty flame, thus difl:'ering from the Scranton mineral
which burns with a clear flame. It dissolves in acid with efferves-
cence ; the calcareous matter seems to be combined chemically with
the humus-like material. He is inclined to see in dopplerite a sub-
stance originating in mere segregation from plant material as the
silica of flints is separated from limestone. He looks upon dop-
plerite as possessing great importance, since in most peats, one finds
cementing substances which, optically, physically and chemicallv,
resemble it closely.

Fruh,^** in his earlier work, already cited, gives an elaborate dis-
cussion and reaches conclusions differing very much in some respects
from those just given. He asserts that dopplerite exhibits the
wholesale formation of ulmin compounds and gives detailed descrip-
tion of its physical and chemical properties to prove that it belongs
to the ulmin group. Owing to the large proportion of calcium, he
thinks the material pre-eminently a Rasenmoor deposit. On wholly
fresh profiles of Rasenmoor at Gonten, Schwantenau and Rothen-
thurm, he saw in the red-brown peat, brown flakes, one centimeter
to one decimeter, so mottling the mass that he termed this type
Marmortorf. \^ery frequently the flakes are associated with a frag-
ment of root or twig, along which water would flow. At Rothen-
thurm he found the dopplerite first along a root. These brown
flocks are always rich in water ; the Rasenmoor is always rich in
water, a condition which favors homogeneous ulminification of the

*S'. Giimbel, op. cit., pp. I2g, 130.

'"J. J. Friih, op. cit., pp. 64, 68, 69-72.

I'ROC. AMER. PHIL. SOC. , I,. 202 MM, PRINTED NOV. 1 6, I9II.

181

584 STEVENSON— FORMATION OF COAL BEDS. [November 3.

peat. The brown flocks are sources of dopplerite. There is no
sharp separation between dopplerite and the surrounding peat —
there is always a passage zone, an intermingling of peat and dop-
plerite.

The mode of occurrence is variable. In many places, he saw
veinlets, one to two meters long and one to five centimeters wide ;
here and there a vein spreads out from a root — one passed over a
thin sandstone and was prolonged horizontally for several meters as
a little bed, at most two centimeters thick. At the same place, he
observed some wedge-shaped veinlets penetrating the glacial drift
to a depth of 3 to 4 centimeters, where it filled cracks in the clay,
binding the fragments into a breccia. There were no plant remains
in the clay, so that the fine gelatinous dopplerite must have been
deposited in already existing cavities. The presence of abundant
water being essential to the ulminification, the mineral is found espe-
cially in the lower part of the peat. As every plant can become
ulminified, dopplerite may occur in any moor, where the temperature
and moisture are in proper relation. He has found the mineral
derived from Sphagnum at the contact between Rasenmoor and
Hochmoor, where the water-rich condition existed.

Kaufmann believed that with the point of a knife he separated
particles of dopplerite from good peat ; Friih did this with Marmor-
torf, but he thinks that even the best Rasenmoortorfs are not usually
so far advanced as that. The microscope detects little flakes pro-
duced bv the flowing together of very tender ulniin material, if the
peat be ripe ; but one cannot determine whether these are ulmic or
humic acid — the quantity is too small. At the same time, he main-
tains that it is an error to identify with dopplerite the caustic potash
extract from peat, as Kaufmann and Muhlberg have done, for potash
combines with ulmic and Immic acid alike. Dopplerite is a higher
member of the ulmin grou]).

Kinahan'"' often observed that, when peat was taken out on the
hills near Dingle bay, little streams of tar, which had filled tubes
made by decav of roots, oozed and trickled out from the newly made

"" G. H. Kinahan, Geol. Surv. of Ireland, Explan. of sheets 182, 183, i<)o,
1861, p. ii.

1S2

I9II.] STEVEXSOX— FORMATION OF COAL BEDS. 585

surfaces. This is clearly the younger stage of dopplerite referred
to by Friih.

The Schieferkohle, studied in detail by both v. Giimbel and Friih,
is a Quaternary deposit observed at several places in Switzerland.
It will be described on a succeeding page. v. Giimbel's"^ type speci-
mens come from Alorschwyl, but he studiefl also specimens from
other localities. The mass is partly loose, like peat, partly dense,
like pitch coal, containing remains of conifers, birches, etc. It is
undeniably peat-like in the less dense portions, where one can recog-
nize mosses and grasses as the predominating constituents. The
denser portions are changed by caustic potash into an opaque mass.
The microscope shows great quantity of deep brown shell-like
splinters of an amorphous textureless substance, which acts as dop-
plerite. In many parts of plants, the same dark brown material fills
the cell spaces. He thinks it not doubtful that the denser condition
of this portion of the coal comes from richer accunuilatif)n of the
amorphous filling material, which he terms Carbohumin. This
Schieferkohle contains vast numbers of pine cones, not deformed,
and of flattened pieces of wood. In many of the latter, he found an
inner woody zone, composed of a soft yellow substance, like rotten
wood, while the bark zone had been changed into a shining pitch coal.

Friih, ^- after studying Schieferkohle from many localities, con-
firmed the view of Heer, Kaufmann and others that the deposits
agree with peat in microscopic character. They are peats more
strongly ulminified. He often found the interior of rootlets appar-
ently little changed, but after a few minutes exposure, they began
to change and at length became brown like the Marmortorf. With
regard to the wood fragments, he thinks that the outer portion was
ulminified early, perhaps before the bog was covered with drift,
whereas the inner portion was merely peated. At the same time he
does not recognize dopplerite in the Schieferkohle.

It is sufficiently evident that the dift'erence between Friih and
the other observers is merely respecting nomenclature. There is
agreement on all matters which concern the questions at issue here.

"' V. Gi'tnihel, op. cit.. pp. 136, 137.

■'^J. J. Friili, flp. cit.. pp. 83, 84. . .

183

586 STEVENSON— FORMATION OF COAL BEDS. [November 3,

This is placed beyond doubt in his later work/'" where he modifies
the broad statements made in his earlier work and shows that the
difference is formal rather than real. He says that dopplerite origi-
nates, as does the peat, out of a varying mass of colloid substances,
free humus acids, salts of humus acids, inorganic substances and
some nitrogen. So one may regard dopplerite as an ulmate, a hu-
mate, a crenate or a mixture of them all, with in addition some inor-
ganic salts. The essential point is that, during the process of peat-
making, a greater or less portion of the vegetable material is brought
into a condition admitting of flowage, so that it may remain distrib-
uted throughout the mass or may be collected into cavities. When
the pores of the peat are filled, farther drainage is possible only to a
limited degree and the material will find its way to the tissues, be-
coming the Carbohumin of v. (iiimbel. To this absorption of Car-
bohumin is due the different effect of pressure upon peat and brown
coal ; in peat the porosity is very great, in brown coal it is small.

Variations in structure or appearance of the peat have been
observed in recent bogs, which are as notable as those found in the
Schieferkohle. Griffith'^'* in describing the Irish peat bogs, said that
bases of the bogs consist of clay covered with a layer of peat, which
is composed of rushes and flags. Above this is another bed of peat,
closely resembling cannel coal, with conchoidal fracture and hard
enough to be worked into snuffboxes. It yields 25 per cent, of ash
and much oxide of iron. This, in turn, is covered with black peat
containing twigs and branches of fir or pine, oak, yew and hazel,
only the bark remaining. Where whole trees were found, the roots
had disappeared.

Lesquereux"'' relates that on the border of the valley of the
Locle, a considerable mass of marl covers a bed of peat, which has
become converted into lignite, hard, fragile and with brilliant frac-
ture. The thickness on the border is barely 3 inches. Farther
downward toward the bottom of the valley, the marl is only 4 feet

°' J. J. Friili, in " Die Moore der Schweiz," 1904, pp. 164, 165, 166, 167.

°* Griffith, cited by S. S. Haldeman in Introduction to 2d Ed. of R. C.
Taylor's " Statistics of Coal," Philadelphia, 1855, p. 166.

°' L. Lcsquerenx. " Quclques rccherches sur les marais tourbeux," Neu-
chatcl, 1845, p. 95.

184

I9II.] STEVEXSOX— FORMATION OF COAL BEDS. 587

thick and the underlying peat, though showing some change, still
retains its peaty character and is a passage from the lignite of the
border to the peat now worked in the open valley. One is left to
conclude that the deposit is continuous from the border to the uncov-
ered peat.

77; f Characteristics of Peat Accuuiiikitions.- — Swamp or marsh
accumulations of vegetable matter consist essentially of remains of
land plants, including the many water-loving types. Locally, as in
the Lebertorfs or Sapropels, one finds freshwater algae and remains
of mollusks, while in many swamp peats the exuviae of insects
abound, often associated with land mollusks. Some of the older
books refer to marine peat. ]\Iacculloch°'^ mentioned a peat found
in Scotland, which was composed of Zostera marina, and several
authors have cited this as a marine peat. But Zostera is the ordi-
nary " eel-grass " of estuaries and is a land plant able to endure salt
water. Al. Brongniart,**' under the title " Tourbe marine," states
that De Candolle saw in the dunes of Holland some peats which burn
well and are composed of seaweeds, notably of Fiicns digitatns.
He, himself, had seen, opposite the rock of Calvados, some extensive
beds of brown material, soft and spongy, which had all the external
appearance of peat, but it could be burned only with difficulty. That
seaweeds may accumulate on a strand, there to form a considerable
deposit, is placed beyond doubt by Potonie's description of such an
accumulation on Heligoland, of which he gives a photograph. But
such deposits are wholly local and possess no importance. Muck,^'*
in the first edition of his work, referred to the occurrence, at several
places along the North sea, of peat evidently marine in origin.
Samples of the material were sent by him to Friih, who submitted
them to microscopic analysis. One consisted almost wholly of de-
caying seaweed ; when dried, it burned with small flame and foul
odor, but it showed no characteristic of peat. Another, a brown
substance washed up on the shore at Blankenberghe, contained no

"'"J. Macculloch, "A System of Geology," London, 1831, Vol. IL, p. 339.
°' Al. Brongniart. " Traite elementaire de mineralogie," Paris, 1807, Vol.
II., pp. 41, 46.

"" F. Muck, "Die Chemie der Steinkohle," 2te Aufl., 1891, p. 164, footnote.

185

588 STEVENSON— FORMATION OF COAL BEDS. [November 3,

trace of algae, but consisted wholly of fragments from land plants.
The same is true of a specimen from the Dollart. After examining
samples from all localities of alleged marine peat, Friih felt himself
justified in the positive assertion that thus far no marine peat has
been discovered.

The classification of peaty deposits has received much attention
from many authors. The literature in America is somewhat limited,
as, until very recent years, peat seemed likely to remain indefinitely
without economic importance. Among the earliest attempts at clas-
sification is that by Shaler,-'-' whose grouping was much in detail.
If e divided the forms into marine marshes and freshwater swamps ;
the former including grass marshes and mangrove marshes, grow-
ing above tide, as well as mud banks and eel-grass marshes, growing
below mean tide ; the latter including river, lake and vipland swamps,
each with two subdivisions. The grass marshes are along the coast
where salt water bathes the roots of the plants, while freshwater
swamps are above tide. Davis, ^°" in discussing the freshwater de-
posits of Michigan, employed the terms bog, marsh and swamp; a
bog is an area of wet, porous land, whose soil is mostly decayed or
decaying vegetable n:atter, loosely consolidated and containing so
nuicli water as to tremble when one walks on it ; the vegetation
varies, but usually consists of mosses, sedges or grasses, or a combi-
nation of them along with shrubs and even small trees; a marsh
does not shake readily when one walks over it, though it may be very
soft and wet ; the vegetation is mostly grass-like, though shrubs may
be present in thickets ; a swamp soil is firm, but wet, even to flood-
ing at times, and bears trees and shrubby plants as the most impor-
tant part of the vegetation. This grouping is not absolute, for the
types ma}' all be found in a single basin, the passage from one to
the other being very gradual.

In luirope, where peat is of great economic importance, many
students have expended great ingenuity in efforts to classify the

'■"' N. S. Slialcr, " General Account of Freshwater ^Morasses of tlie United
States," Tenth Ann. Rep. U. S. Geol. Survey, 1890, pp. 261 et scq.

'"" C. A. Davis, "Peat." Ann. Rep. Geol. Survey of ^Ntich.. 1907, pp. 108,

loa

186

'91 1-] STEVENSON— FORMATION OF COAL BEDS. 589

deposits, which are, practically all of them, freshwater, marine
marshes being unimportant economically. Lesquereux, in 1845, rec-
ognized two general types of bogs, which he termed supraaquatic or
emerged and infraaquatic or submerged, the former being above
the waterline and the other at or below it. The prevailing classifi-
cation in Germany recognizes the Hochmoor, equivalent to the
Heathermoors of Scotland, and, in great part, to the supraaquatic
of Lesquereux ; the Wiesenmoor, Griinlandsmoor, Niedermoor, or
Rasenmoor, equivalent to the bogmeadows of other lands ; and the
Waldmoor or forested bog. These are the Lyngmose, Svampmose,
Hoermose ; the Kjaermose, Engmose ; and the Skovmose of the
Danish authors. A similar division is that of Hochmoor, Flach-
moor and Zwischenmoor, these being the terms employed by Potonie
and some recent authors.

Potonie"" has described a great moor in east Prussia on the delta
of the Memel and Xemonien rivers, which shows the relations of
the several types. Going eastward from the shore, one finds first
the mud, which on the border is held by water lilies and other plants,
referred to as " landmakers " because they are outposts. Higher
plants, especially canes, occupy water areas, behind which there
develops a meadow Flachmoor of sedges, where frequent floodings
prevent growth of trees. Beyond that, foresting begins, and one
reaches a moor of black alder, several kilometers broad. The sur-
face is occupied by swamp plants, such as Iris, SiiDii, sedges, which
endure well the periodical floodings of this zone. If the area were
one of gradual subsidence, equal to the accumulation, the condition
would continue for a long period. The surface rises gently and one
comes to another flora, accustomed to somewhat drier soil, with
alders, hops and nettles. Thus far, one has followed the Flachmoor
or Xiedermoor ; but at a little distance beyond, swamp birches are
seen among the alders. The latter soon disappear and the birch
zone is reached, beyond which is a zone of forest with Piiiiis sylves-
tris and Picea cxcelsa. These form the Zwischenmoor or Waldmoor.

In this passage zone, the peat has risen so high that the surface
is drv ; the forest is here, but as one advances the trees become

^''' H. Potonie, " Die Entstehung," etc., pp. 35-40.

187

590 STEVENSON— FORMATION OF COAL BEDS. [November 3,

smaller because increasing accumulation of peat deprives them of
their nutriment. Even exceptionally high floods cannot bring dis-
solved nutriment to them and they are dependent on rain, dew and
dust. At length, the trees are displaced by Sphagnum, able to store
away dew and rain, to remain moist on even a dry bed, to keep the
area wet though it may be several meters above the water level. So
one, in going eastward, is still on wet land. This is the Hochmoor,
swelling as an hour glass — whence its name. But there is a still
higher stage. On the Hochmoor, one's foot sinks deeply into the
sphagnum-peat as he advances. At length a pond is reached; the
rain collects in pools or small lakes, whence it flows to moisten the
surrounding area. Plants thrive here because the changing water
gives them nutriment. Reeds and sedges are seen and even Pimis
syk'cstris is present, though much smaller than on the borders of the
Flachmoor. This great bog rests on a sandy deposit, with which are
mingled the vegetable muds of the kurischen Hafif.

As the problem of formation of coal beds is world-wide in scope,
the essential features of those beds being practically the same in all
lands, the study of peat accumulations must be as broad as possible,
if the conclusions are to possess any worth for or against any theory.
In the pages to follow, the results of studies by observers in many
regions will be presented in detail. This may involve some repeti-
tion, but that will serve only to emphasize the importance of certain
conditions, which have been overlooked or ignored in .some contri-
butions to the discussion.

Peat Deposits in the United States of America. — Alarine marshes
exist in extensive areas along the Atlantic coast from Maine to
Florida, a region believed by nearly all observers to be subsiding.
North from Florida, the tidal marshes are grass-meadows, ordinarily
treeless. They are covered with grasses, reeds or coarse sedges and
the upper surface is near the level of high water. Cook^"" has
described those of New Jersey, which are typical of the whole coast
from Georgia northward. Alongside of streams crossing the marshes
there is a narrow ridge of dry land, but within a few yards one

""G. H. Cook, "Geology of New Jersey," 1868, pp. 24, 231, 233, 238, 300,
347-350, 361.

188

191 1.] STEVENSON— FORMATION OF COAL BEDS. 591

reaches the permanently wet area. Immediately below its sod, is
mud or soft earth, which varies greatly in composition. Near the
creeks, it is usually fine clayey mud with embedded roots, the whole
evidently transported material ; at a little distance, it is black earth
or muck, formed in a swamp ; while at a greater distance one finds
only a mass of fibroits roots and vegetable matter with no admixture
of earth or mud. The last two are of in j///« origin. The"meadow^s"
along the Passaic and Hackensack rivers, emptying into New York
harbor, show an extreme thickness of 32 feet of '' mud " resting on 8
feet of blue clay, while farther up the stream are great marshes
resting on fine sandy material. One sees on the surface of these
meadows great numbers of white cedar stumps and the mud is
crowded with remains of cedar timber.

The condition is due to encroachment by the sea, whereby the
treeless marshes advance inland and overrun the white cedar swamps
along the streams ; one finds at many places the old cedar forest
buried in the tidal marsh, while the cedar swamp still exists at a
little way beyond. The salt water kills the freshwater grasses and
the trees on the border. In many places trees flourished 80 years
ago, where one finds now only salt marsh muck. The white cedar
is a very durable wood ; trunks of trees killed by the salt water are
still standing in localities where several feet of muck have accumu-
lated around them.

Lyell"'" observed the efifects of this encroachment in Georgia.
In coming down to the coast, he found the trees becoming dwarfed
and at length disappearing to be replaced by reeds ; but in the marshes
he saw the stumps and stools of cypress, still retaining the erect
position in which they had grown. He cjuotes Bartram, wdio stated
that when planters, along the coast of the Carolinas, Georgia and
Florida, as well as westward to the Mississippi, bank in the grassy
tidal marshes for cultivation, they " cannot sink their drains above
three or four feet below the surface, before they come to strata of
cypress stumps and other trees, as close together as they now grow
in the swamps."

^*"' C. Lyell, "Second Visit to the United States of North America,"
London, 1850, Vol. L, pp. 334-336.

189

592 STEVKNSOX— FORMATION OF COAL BEDS. [November 3,

When one reaches southern Florida, he finds a different type of
tidal marsh. Northward, grasses and rushes are the plants which
advance the land seaward, hut at the south the mangrove is the
agent. That plant abounds on coasts in tropical America and is
found northward in Florida to lat. 30°, though it is not abundant
above lat. 26°. The eccentric mode of growth exhibited by the
special type under consideration, long ago attracted the attention of
botanists. Bancroft^"* says that it rises from several strong woody
roots which emerge from the ground for two or three yards before
tliev unite at the trunk. Tough woody shoots, about three inches in
circumference, descend from the trunk to take root and, as the tree
increases in size, the shoots increase in number. These by their
strength compensate for the looseness of the soil. The tree grows
in a low, wet soil by the side of running w'ater.

The Florida mangrove flourishes only in contact with salt water,
being stunted by brackish water. Vaughan'"^' describes it as attain-
ing the height of 10 to 20 feet and as grownng in water or so near it
that the soil is saturated. The long seeds take root in water not
more than one foot deep, leaves being put forth as soon as the sur-
face is reached. Besides the tufty roots given off at the base, there
are others originating at higher levels from the stem, which grow
downwards and embed themselves in the soil. Shaler says that
these can descend through 8 feet of water in order to take root.
Each becomes a new tree to be multiplied in similar manner. Thus
a tree ma\- advance 20 or more feet in a century, the advance being
checked only when the water is too deep or the waves prevent root-
ing. These growths, as described by Shaler and Vaughan, form
dense thickets, a fringe, which is made denser by litter from the
trees ; so that debris from the land eventually fills up the space
behind and the trees are killed. lUu, in the interval, a new fringe
has been formed. In the moist area behind the growth, freshwater
types displace the saltwater forms and a swamp results. Shaler

"" E. Bancroft, "An Essay on the Natural History of Guiana in South
America," London, 1779, pp. 76-79-

105 J -^y Vaughan, " Geologic Work of Mangroves in Southern Florida,"
Smithsoii. Misc. Coll. Ouart. Issue, Vol. V., 1910, pp. 461-464

190

'91I.I STEVEXSOX— FORMATION OF COAL BEDS. 593

conceives that the Everglades of southern Florida, with an area of
about 7,000 square miles, owe their origin to outward advance of
mangroves on shallows of the coast.

The freshwater swamps of the Atlantic and Gulf coasts are, for
the most part, sharply distinct from the tidal marshes, even where
the latter have encroached. Cook^''" has shown the relation in X"ew
Jersey by a section extending from Dennisville to Delaware bay, a
distance of about one mile. The cedar^"' swamp begins at the edge
of the low upland and gradually deepens to 15 feet. Like most of
the cedar swamps in Xew Jersey, it has been cleared, but clusters
of young trees up to 100 years old remain here and there on the
surface, which is only a few feet above high tide. The cedar grows
densely but slowly. Old stumps show more than 1,000 annual rings,
but those near the bark are as thin as paper and the stumps rarely
exceed 3 feet diameter, though some have been seen which were 7
feet. The swamp soil is black, peaty, 13 feet thick at Dennisville
and, when dr}'. burns. It shows no admixture of foreign material
and contains only 3.35 per cent, of ash, the water in the dried peat
being from 12 to 16 per cent. It is very loose and porous, always
full of water; the roots of the trees run through it in every direc-
tion near the surface, but do not penetrate to the solid ground.
Where the peat cover is thin, the roots do pass through to the under-
lying soil, but, in that case, the wood is inferior and it cannot be
utilized in manufactures.

Trunks of trees are buried at all depths and are so numerous that
one has difficulty in thrusting a sounding rod to the bottom. Some
had been blown over when rotten ; others were merely uprooted.
Some, blown down, lived for a considerable time afterward. The
prostrated trunks lie in all directions and the conditions are precisely
the same as those now seen on the surface of the swamp. Large
stumps have been found, which grew over logs, now enveloped by

'"" G. H. Cook, op. at., pp. 301. 302, 355, 356, 360, 361, 484.

'"^ The cypress or white cedar of X^ew Jersey is Chamacyparis thyoidcs,
which is found in swamps from Xew Hampshire to Florida and westward
to the Mississippi. The bald cypress is Taxodhim distichuin, a form surviv-
ing from the middle Tertiary, which extends from southern Delaware along
tlie coast to Texas and up the Mississippi to southern Illinois.

191

594 STEVENSON— FORMATION OF COAL BEDS. [November j,

their roots, and at the bottom are found worthless logs of cedar
belonging to trees which were rooted in the solid ground below.

Shaler^'"* has given a general description of the Dismal Swamp,
an area of about 500 square miles, at only a few feet above tide
level. It was much larger, but a great part has been reclaimed by
draining. The peaty deposit rests on Pliocene sands, of which 10
to 14 feet are exposed on the border ; but this is not wholly certain
as the bottom has been reached at only one place within the swamp.
C. A. Davis has stated recently that the peat is at least 15 feet thick
and of good quality. On the western border is Drummond lake,
6 feet deep and somewhat more than 2 miles wide. Shaler says
that, here and there within the swamp, one comes to drained areas
of considerable size, one of which, embracing about 2 square miles,
has long yielded fine crops of maize. He notes that Sphagnum has
a very small place in this swamp and that it is an unimportant factor
everywhere south from the Potomac and Ohio rivers, where the
greater heat and decreased rainfall prevent its luxuriant growth.
The most important peat-making plants in the region south from
those rivers are canes, a grape, the bald cypress and the juniper with,
in some localities, the dwarf palmetto — among these, he assigns the
chief place to the common cane.

The greater part of the Dismal Swamp is under water during
most of the time, but there are elevations rising not more than 3
feet above the general level ; yet the drainage due to this slight ele-
vation suffices for growth of pines belonging to the common southern
species. In the main area, water-covered, one finds three trees, Ta.vo-
diiDii disiichnm, the bald cypress; Junipcrus virginiana, the juni-
per; and Nyssa syk'atica^the black gum. The juniper occupies spots
usually somewhat desiccated during the dry season, but the others,
being provided with special appliances, live where their roots are
covered with water during even the growing season. The forest is
very dense and passage through it is rendered difficult by projecting
knees of cypress and the arched roots of Nyssa, while everywhere
is a profusion of other plants. The surface is covered with a litter

'»■■' X. S. Shaler, Tenth Ann. Rep. U. S. Geol. Survey, pp. 293, 313, 321,
PI. K, <), 10, V\g. 29.

192

«9>i] STEVENSON— FORMATION OF COAL BEDS. 595

of fallen trunks, twigs and leaves. Shaler's plates from photographs
taken in this forested swamp show the conditions thoroughly.

Shaler"'-' has described the peculiar modification of structure
characterizing the bald cypress. This is the greatest of the conifers
east from the Rocky mountains and it is the most stately of all the
trees on the eastern half of the continent. On dry ground or where
there is no water during the summer half of the year, it shows no
peculiarities ; but where it lives in swamps, flooded during the grow-
ing season, the roots give ofif excrescences which project above the
water, their height depending on the depth of water. These " knees "
are subcylindrical and are crowned by a cabbage-shaped expansion
of bark, rough without and often hollow within. Whenever these
knees become permanentl}' submerged during the growing season,
the tree dies ; as was proved in the New Madrid area, where, during
the 1811 to 1813 earthquakes, the land sank permanently. In Reel-
foot lake, within Kentvicky and Tennessee, thousands of these long
cypress boles still stand in the shallow waters, though 70 vears have
passed since the slight submergence of their knees. The eitect of
drowning is shown on a plate in the work previously cited. Many
dead stems of cypress rise above the surface of Drummond lake,
which is only a few feet deep. Lesquereux thought that these were
once part of a floating forest.

Okefinokee swamp in southern Georgia is not wholl}- a forested
swamp. It is larger than Dismal Swamp and more difficult to study.
Harper^'" succeeded in penetrating it to a distance, all told of about
18 miles. Here and there are islands, raised a little above the swamp
level, at times not more than 2 feet, often less. On those the slash
pine and the black gum grow, while all around are sphagnous bogs
in which are slash pine, as well as swamp cypress, with sedges, ferns,
sundews, and pitcher plants. Pines are wanting where the muck is
more than 4 feet deep, but the cypress grows densely until the depth
exceeds 6 feet. Where that depth is exceeded, no trees are found

"" N. S. Shaler, " The American Swamp Cypress," Science, O. S., Vol.
II., 1883, pp. 38-40.

""R. M. Harper. "Okefinokee Swamp," Pop. Sci. Monthly, Vol. LXXIV..
1909, pp. 596-613.

193

596 STEVENSON— FORMATION OF COAL BEDS. [November 3.

and the surface is a "prairie." This type has an area of 100 square
miles in the western part of the swamp, covered everywhere by
water in wet weather, so that one ma}' go in any direction in a canoe.
Canes, pickerel weed and water lilies abound but Sphagnum is
absent, as in this latitude it can grow only in shaded places. Stumps
of cypress are abundant and the peat is about 10 feet thick. The
Florida swamps, described by Harper and others in the official re-
ports, show all types from the open marsh to the forested swamp.
The cypress swamps of the Lake region have grass marshes near
the water, which are separated from the dense cypress growth by a
narrow belt of small willows. The peat in these deposits is worth
little commercially, as it is crowded with logs and woody roots. The
great Everglades area belongs to the stagnant water type.

The cypress swamps of the Gulf coast are like those of the
Atlantic coast. LyelP^^ relates that, in excavating for the founda-
tions of the New Orleans Gas Works, the contractor soon discovered
that he had to deal not with soil but with buried timber; the diggers
were replaced by expert axemen. The cypress and other trees were
" superimposed one upon the other, in an upright position, with
their roots as they grew." The State Surveyor reported that in
digging the great canal from Lake Ponchartrain, a cypress swamp
was cut, which had filled gradually. " for there were three tiers of
stumps in the 9 feet, some of them very old, ranged one above the
other ; and some of the stumps must have rotted away to the level of
the ground in the swamp before the upper ones grew over them."

Conditions in the cypress swamps are the same throughout,
whether the prevailing tree be bald cypress or white cedar. The
peat is formed by accumulation of litter in the dense forest and, for
the most part, the swamps are due to impeded drainage on an almost
level surface. The trees are rooted in the swamp material, which
at times is of great thickness, more than 150 feet of muck, carrying
cypress trees on its surface, being reported from Florida. Such
trees find ample nutriment in peat containing less than 4 per cent,
of mineral matter and they do not send their roots down to the solid
ground. One sees growing amid such conditions not merely shrubs

"' C. T.yell, " Second Visit," etc., Vol. II., pp. 136, 137.

194

191 1-] STEVENSON— FORMATION OF COAL BEDS. 597

but also majestic trees, such as cypress and gum. which, as well as
the less imposing juniper, yield wood of great importance to the
artificer.

The inland swamps of the northern states dift'er in many wavs
from the coastal swamps. They occur along river borders or in
lakelet areas of the drift-covered region. In great part, the former
are "wet woods'" covered more or less deeply with water during
several months of each year, but they show considerable stretches
of true swamp. The swamps and marshes of the drift region are
less extensive, but they afford better opportunity for studies bearing
on the mode of accumulation. They have been investigated bv C. A.
Davis, H. Ries, N. S. Shaler and others, but the most comprehensive
and most recent description is by Davis.

Davis^^- notes that very few highly organized plants can grow
wholly submerged in water, and those are mostly endogens ; lo feet
of depth seems to be the limit, although Potamogeton has been found
rooted in 23 feet : other types, low forms such as Cliara and the
floating algse are indift'erent. Some plants, burweeds, arrowheads,
reed grass, pickerel weed and water lilies can grow when partially
submerged ; while some land plants, shrubs and trees can endure
long exposure to water about the roots. The surface growth on
swamps is important. Elm and black ash swamps are of common
occurrence and have, besides those plants, tamarack, spruce, willows,
alders, with various heaths and mosses. They do not always show
much peat, but what there is is well decomposed and is apt to contain
much mineral matter. The greatest thickness of peat in these
swamps is reported to be 10 feet. Tamarack { Lari.v lariciua) and
white cedar (Chanuccy parts tliyoidcs) indicate the presence of peat,
the latter growing densely on the surface of a deposit, 20 feet thick.
Spruces {Picca mariana and P. brcvifoUa) also grow on thick peat;
willows, poplar and alders grow on the thickest peat and in wet
places; but the mosses, Hypmim and Sphagiiuin, grow onlv in
advanced swamps.

^ C. A. Davis, " Peat, Essays on its Origin, Uses and Distribution in
Michigan," Rep. Mich. Geol. Survey for 1906, pp. 121-125, 128-134, 136-141,
153. 154, 157-159, 160-166. 203, 204, 208, 213, 269, 275, 279, 291.

195

598 STEVENSON— FORMATION OF COAL BEDS. [November 3.

Peat deposits fill depressions but, in some cases, are formed on
almost level areas. Depressions more than 25 feet deep may be
filled by alg^e, by floating species of seed-bearing plants, by sedi-
mentation, by plant growth from the sides or by a combination of
these processes. A frequent succession is Chara-marl, on which
rests a peaty soil in which plants take root ; the land marsh moves
out and tamarack advances on the deeper peat of the shore. As
the water becomes shallower, each shore type moves out and is suc-
ceeded by the type behind — the water growing warmer and more
aerated. Formation of peat on a flat space is much under the same
conditions as those on the surface of a filled depression. When the
drainage is poor, liverworts or some mosses take possession; if not
too wet, rushes, sedges and grasses appear. Accumulation makes
the place wetter and only the hardier plants remain. Sedges are
the chief peat-producers under these conditions.

The process of filling a depression is often very complicated.
In southern Michigan, the early stages are shown in many lakes,
which are surrounded by zones of aquatic plants. More or less
detritus, organic and inorganic, finds its way into the lake. Where
the process is more advanced one can trace the whole succession.

The lowest deposit is formed of Cliara and floating algc-e. This
is succeeded in the shallower water by the Potamogcton zone and
that bv the water lilies. Just beyond this one comes to the floating
mat of sedges, extending on the water surface to a considerable
distance from the shore and buoyant enough to support a consider-
able weight. The earlier stages may provide soil for rooting of the
sedges at the shore line, but the mat itself is wholly unsupported for
a considerable distance and is often 18 inches thick. Finely divided
material from the undersurface of the mat increases toward the
shore, where it becomes dense and the mat is no longer floating.
Thus is built the solid peat, structureless, decomposed and nearly
black. The surface rises gradually after grounding of the mat and,
at each level, new plants appear. Shrubs and Sphagiinni advance
to be overcome in turn by tamarack and spruce, which in their turn
are overcome by the marginal flora from behind. Tamarack accom-
panied by ferns grows far out on the bog.

196

19-1.] STEVENSON— FORMATION OF COAL BEDS. 599

The final stage is where the sedge mat closes over the surface
and the underlying peat has become firm. Sedge is usually the chief
factor in the later stages of lake destruction. At times, the mat is
pressed down by the weight of trees growing on it. In one case it
was found 6 feet thick, resting on semi-fluid peat. A section at
one locality showed

Feet. Inches.

1. Sphagnous peat O 6

2. Moss peat and shrubs 2 o

3. Moss peat 0 3

4. Coarse brown peat, stumps and roots ... 2 6

5. Remains of shrubs o 2

6. Dark peat rich in sedge remains 2 0

It was impossible to determine the condition farther down as the
peat was very wet, but sedges were recognized. Similar conditions
were observed in other sections. These all show that the trees w^ere
rooted in the mat of pure vegetable material, even when it reposed
on the water surface and that, while the trees were growing, the
accumtdation of peat was continuotis.

After the mat has been grounded, Hypiuini hastens outward
from the shore, associated occasionally with some Sphagmini. When
the surface rises 2 inches above the water level, ferns appear and
they are followed by Spliagnum, which persists even when the sur-
face is flooded. It is much hardier than Hypiium and, for that
reason, it has been regarded as chief factor in the production of
peat. Bttt it is often absent, having been found in less than 30 per
cent, of the localities examined by Davis. The first tree is the tama-
rack, which grows densely on the level of shrubs, but isolated trees
are scattered over the open bog.

Chara-marl occurs frequently in southern ^Michigan but it was
not seen anywhere in the northern portion of the state, where the
general succession dififers somewhat from that already given. The
Chara-stage is wanting ; pond weeds, pond lilies and rushes are of
irregular occurrence and the sedge-zone is all important. Owing,
probably, to absence of fragments belonging to the higher plants,
the work of freshwater alg^e is more apparent than in the southern

PROC. AMER. PHIL. SOC, L. 202 NN, PRINTED NOV. l6, I9II.

197

600 STEVENSON— FORMATION OF COAL BEDS. [November 3,

peninsula. Algal lake, now covering only a few acres, is surrounded
by a great wooded swamp, extending northeastward to a large lake
and coming down almost to the water at the north end of Algal lake.
The swamp loosestrife {Dccodon vcrticillatus) forms the marginal
zone. The bottom of the lake is covered with soft flocculent ooze,
composed of unicellular alg?e with diatoms as well as pollen from
conifers. Davis conceived that peat of this type would be like
cannel and he thinks that freshwater algae may have been more
abundant in Carboniferous times, when all types of plant life were
lower than now. A similar material was found in a mature bog,
where the section is

Feet.

1. Coarse peat, with stumps, roots and fallen stems 5

2. Brown peat, good texture, quite plastic 5

3. Soft, light-colored peat, like that at Alga! lake 4

These are the only localities in the United States whence this type
of peat has been reported. Ehrenberg, Friih and Potonie have de-
scribed the felt or Meteorpapier, as Ehrenberg termed it, which
remains on swamps after floodwaters have been drained ofif. Potonie
calls it Sapropel carpet, and he has given a photograph showing the
material covering land plants of a swamp. But the phenomenon is
of by no means rare occurrence in the eastern part of the United
vStates. Davis has communicated by letter that he saw it in 1910
near St. Augustine in Florida, where the water of a swamp had
been lowered ; the felt was conspicuous on the tussocks, etc. In the
Everglades of the same state, he found the felt about the grass and
sedge stems in the level swamps. Here and there it contained a
considerable quantity of calcareous matter, due perhaps to activities
of Cyaphanacese present in the algal association. The same type of
felt-like development is seen during springtime in marshes of the
northern states, where the water drains ofif slowly. Spirogyra and
other filamentous alga? sometimes cover the temporary ponds and
are left as a felt-like cover when the water has been withdrawn.
This felt breaks into small pieces as it dries and is added to the peat.
The writer has observed it in very small patches on the New Jersey
marshes; he has seen patches more than lo feet square at many

198

I9II-] STEVEXSOX— FORMATION OF COAL BEDS. 601

places in Rhode Island and Massachusetts. But in every case, the
quantity is insignificant as compared with the mass of other vege-
table material and this algal contribution must be wholly unimpor-
tant. At the same time, one can conceive of conditions which could
render it important.

Shaler expressed the prevailing opinion when he asserted that
the presence of moisture determines the distribution of plant life
in swamp areas. Advance of sw-amp destroys the forest. He had
seen many places on the coast of Maine as well as in northern ]\Iich-
igan and Wisconsin, where invasion by Sphagnnui made the surface
so wet that even the most water-loving trees of those regions could
not maintain themselves. Davis, in his work on Michigan peats,
has discussed the causes leading to the succession of vegetation in
swampy areas. The shrubs growing at the water level are drought
plants, though living where water is abundant ; their leaves are
linear or even scale-like ; the cuticle is dense and the leaves are pro-
tected by a waxy or at times resinous coating — all contrived to
prevent too rapid evaporation. The explanation of the condition is
complex, but it depends mostly on the difficulty with which moisture
can be extracted from peat. Once thoroughly air-dried, peat is
almost impervious to water, so that plants growing on peat or a
peaty soil suffer more from drought than those on other soils. Even
when wet, it has little water for plants growing on it. A noteworthy
fact in this connection is that some plants, growing near water level
in southern Michigan, are found growing only on dry soils in north-
ern Michigan. They find their drought-resisting ability equally
essential in both regions. The distribution of these plants is ex-
plained by the fact that they have fleshy fruits, which birds eat
during their southward migration and the seeds are scattered over
moist areas. \Miile the plants must be able to resist drought, they
must be able to endure excess of moisture in some localities. Davis
saw Bctula piiiiiilla and some willows living in places where their
roots had been covered with one foot of water for several years.

The conditions of advance described by Davis are familiar in
other states. They exist even on high swamp areas, as appears

199

602 STEVENSON— FORMATION OF COAL BEDS. [November 3.

from Bradley's"-^ notes on the disappearance of meadows which
were used as camping places in the Sierra Nevada. Fifteen years
ago, these were open and covered with abundant grass. Originally,
they were ponds or lakes which became filled with peat, on which
grass thrived. As the material became less wet, tamarack seeds,
blown in from the border, took root, but the young shoots were
killed by the frequent fires. Since protection against fire has be-
come complete throughout the region, the tamarack has advanced
so as to occupy much of the surface, while pines are encroaching,
which eventually will crowd out the tamarack and will occupy the
whole area. The trees are rooted in the peat.

Bates"" has shown that swamp conditions and luxuriant growth
of trees are not incompatible. In describing the forests of Para,
he says that one swampy area was covered with trees more than 100
feet high, all of second growth. In another swamp, the air was
marked by a mouldy odor, the trees were lofty and the surface was
carpeted with lycoi)odiums. Farther down in this area, where the
ground was more swampy, wild bananas, great palms and exogens
grew luxuriantly and were covered with creepers and parasites;
while the surface was encumbered with rotting trunks, branches,
leaves, and the whole was reeking with moisture. Kuntze, already
cited, states that the tropical swamps are densely wooded. Obser-
vations by other authors will be referred to in another connection.

Peat Deposits in Europe. — The importance of peat as fuel in
Europe has led to thorough investigation of that material from every
conceivable standpoint. The literature is so extensive and, in great
part, so excellent that one, compelled by limits of space, finds him-
self embarrassed in selection of authors as well as of matter.

Lesqucreux"* long ago proved that Spliayniiin is not the impor-
tant factor in peat-making; he recalled attention to Ad. Brongniart's

"'" H. C. Bradley, "The Passing of Our .Mnuntain Meadows," Sierra
Club Bull., Vol. VIII., 191 1, pp. 30-42.

"^ H. W. Bates, " Tlie Naturalist on tlie River Amazons," London, 1863.
Vol. I., pp. 44, 47, 50, 51-

"' L. Lesquereux, " Quel(|ucs reclierches sur les marais tourheux," pp. ;^2,
III, i2r, 137; 2d (}eol. Surv. Penn., Rep. for 1885, pp. 107-121.

200

I91I.] STEVENSON— FORMATION OF COAL BEDS. 603

observation that evaporation from that moss is proportionately less
than from other plants ; and he showed that growth of the moss is
checked by freezing and that the plant cannot live in deep shade or
under forest trees such as oaks, pines or beeches. He seems to be
the first to note that marls covering peat bogs contain impressions
of plants.

Lesquereux's conception of the mode of filling depressions from
the sides differs somewhat in detail from that given for the United
States. Shallow ponds are invaded by vegetation, which forms a
mould in which water plants take root. The basin is filled by their
decay, the surface becomes humus in which plants of other types
grow, giving meadows or forests. The filling is rapid in the early
stages. Pools of quiet water are invaded by confervce, mingled with
infusoria, microscopic plants and small shells, which by decay cover
the bottom. At times, 6 to lo inches of this deposit may accumu-
late in a year. When the water is deep, the same result is reached
by another process — the prolonged growth of certain floating mosses,
especially of some species of Sphagnmn. Those, pushing out from
the sides, form a thin cover, in which grasses, sedges and other
water-loving plants grow. Eventually, this becomes compact enough
to bear the weight of trees, even of dense forest; until, becoming too
heavy, it either breaks or is pressed slowly to the bottom and covered
with water. This, he asserts, is no hypothesis but the statement of
actual fact.

The lac d'Etailleres, near Fleurir in Switzerland, is open water
in an extensive series of peat bogs. Prior to the year 1500, it was
the site of a forest ; but in that year, according to legend, the forest
disappeared and it was replaced by two lakes. The lakes still exist
and in quiet water one can see the prostrate trees on the bottom.
But a new carpet has already spread over much of the surface, which
in turn will become forested and will sink. Thus one mav find
superimposed beds of decomposing vegetable matter, each consisting
of remains of small plants below but of forest remains above. An
analogous condition exists in Lake Drummond of the Dismal Swamp,
where the bottom consists of a forest cover, once at the top but now

201

<504 STEVENSON— FORMATION OF COAL BEDS. [November 3,

under water, while vegetation is encroaching from the sides. It is
quite possible that this explanation of the Lake Drummond condi-
tion is correct, but that lake is shallow, only 6 feet, and the trees are
erect ; in the deeper lac d'Etailleres. the trees were prostrated by
breaking of the mat. To illustrate the succession in such a case, he
gives the section of a bog in Denmark :

Feet. Inches.

1. Fibrous yellow peat with undccomposed mosses 3 8

2. Oak layer, wood still sound, trunks 2 to 3 ft. diameter.

3. Peat, yellowish 6

4. Birches, prostrate, Bctuhi alba 3 o

5. Black peat 4 o

6. Pines, 6 to 10 inches diameter, most of them pointing

toward center of the basin, retaining their branches,
embedded in a mass of leaves, cones, etc 8 o

7. Black compact peat 4 o

and the bottom not reached. This peat was mined for fuel, the
works being extensive. The general description by Lesquereux
shows that the conditions are not wholly the same in his localities as
in many areas within the United States. They suffice to show that
Spliag)iii}ii is a late arrival, though in Switzerland, as in some other
portions of Europe it is more important than in this country, where
sphagnum-peat rarely exceeds 3 feet.

As illustrating this, one may cite Vogt's^^^ description of a
Hochmoor at the Fonts of the Canton Xeuenburg. This lies be-
tween two villages built on limestone benches on opposite sides of a
valley. In the middle ages, each village was visible from the other,
but that is no longer the case. The bog has raised itself, hill-like,
growing most rapidly along the middle line. This mass is ^^/'/za^rwwm
and its mode of growth shows well the ability of that moss to retain
water, so as to thrive at considerably above the water level.

Heer"" says that life on land began with minute forms and few
types. So, in the water, alg?e begin the work. Even pure fresh-

"° C. Vogt, " Lehrbuch der Geologie," 2te Aufl., Braunschweig, 1854, Vol.
XL, p. no.

'" O. Hcer, " Die Schieferkohlen von Utznach und Diirnten," Zurich,
1858, pp. 1-4.

202

19"] STEVEXSOX— FORMATION OF COAL BEDS. 605

water, exposed to air and light, is full of minute plants, with bound-
less capacity for multiplication, forming in vast legions, which sink
and form a layer of organic material, the basis of formations com-
posed of higher organisms. These are followed by floating mosses,
which, in spite of their small size, soon produce a great mass of
organic material. The bladderworts, water milfoils follow and the
water lilies spread their leaves over the surface ; reeds press out
from the shore and sedges of various kinds form a wickerwork of
roots, which gradually spread over the whole depression and water
is no longer visible. Meanwhile the peat has been growing denser,
drawing water from below and keeping the bed moist. In it nestle
the milfoils and heaths. The lake closed, woody plants encroach,
Bctiila and then Pinus sylvcstris. But the latter does not grow high,
breaking off after attaining a certain height and weight, sinking into
the underlying soft material, there to be destroyed and converted
into peat as are the shrubby plants. These trees are readily over-
thrown by the wind and the peat is crowded with the overturned
trunks of birch and fir. The harder parts offer prolonged resistance
to chemical change and are embedded in a pulp-like mass derived
from the softer parts. The conditions in all stages are recognizable
in Swiss deposits. The succession may be varied by climatic changes,
whereby a W'aldmoor may be converted into a Torfmoor and that in
turn into a Waldmoor again.

Friih's^^' descriptions of conditions in Switzerland and Germany
are much like those given in later years for localities in the United
States, though the succession of events may differ somewhat in
detail. At the same time, the Hochmoor or 6" /'/;«(/;;//»/ deposit seems
to be built up on the Rasenmoor, composed of Cypcracccc, Phrag-
mites and Hypnuui; islands of Hochmoor were seen occasionally in
a Rasenmoor. Lorentz is cited as having examined 57 moors, of
which 31 were Hochmoors developed on Rasenmoors. Friih inves-
tigated Hochmoors in Steiermark. the Bavarian highlands and in
Switzerland, all of which showed that Sphagnum is a late arrival in

'" J. J. Friih, " Ueber Torf und Dopplerit," pp. 5, 7-9, 15, 18, 20.

203

606 STEVENSON— FORMATION OF COAL BEDS. [November 3,

the peat. In the great Digenmoors of the Bavarian highlands he
found

Meters.

1. Black peat, with Sphagnum i to 1.2

2. Homogeneous black-brown, compact, plastic peat, with

layers of crushed birch stems ; a few specimens of
Sphagnum, but 90 per cent, of the mass consisting of
roots of Cyperaceae i to 1.5

3. Wood layer of conifers 0.4 to 0.6

4 Glacial drift.

He gives measurements from fourteen locaHties in Switzerland, only
one of which failed to show the succession observed in the section.
The exception is a Hochmoor Avithout Rasenmoor foundation and
resting directly on a layer of wood remains. One group seems to
contradict Sendtner's generalization that Hochmoor accumulates only
in localities where the water is not calcareous. This, the " Todte
Meer," is a typical living Hochmoor, near Willerszell, bearing on its
surface many hummocks nearly equal in height and basal diameter,
and bordered by a mountain stream, whose drainage area is in a
limestone region. It shows

Meters.

1. Hochmoor, Sphagnuni 0.2 to 0.3

2. Felted Rasenmoor, upper part consisting of Carex and

Arundo, with scattered alg.T ; lower part with
Hypntim 3

3. Almost pure well-preserved Hypniim.

4. Clay and gravel.

He finds a simple explanation in the fact that the stream, at high
water, does not wet the Spliaginun. It may be well to note here
that in Michigan, according to Davis, SpJiagmon is indifferent to the
character of the water, the presence of calcium carbonate in no wise
affecting its growth.

Friih reports 48 Hochmoors in the Alpine region as originating
on Rasenmoors. Y. Bemmclen and Staring are cited as having
proved the same relations for the provinces of Orenthe, Friesland
and Gottinguc in Holland. The Rasenmoor does not require hard
water, for the vast moors of the Rhine and Maas area are watered
bv those streams, which contain only 65 and 41 millionths of calcium
and magnesium compounds. The relation between Hochmoor and

204

I9II-] STEVEXSOX— FORMATION OF COAL BEDS. 607

Rasenmoor is not always apparent as either one may be very thin
and the other very thick. In his later, great work on the Swiss
moors, Friih has described with much detail all the Swiss deposits
and he has offered generalizations which will be considered in
another connection.

It had been suggested by some observers that the tree trunks
found in the bogs had been drifted into the depressions, but Friih
asserts without qualification that they are in place. The condition
is wholly normal. A. Geikie,^^** after noting the differences in phys-
ical structure as well as in vegetation shown by successive portions
of a bog, says that remains of trees are common. Some are em-
bedded in soil underneath the bog; others are in the heart of the
peat, proving that the trees lived on the mossy surface and finally
were enclosed in the growing peat. This is illustrated by a sketch
of a peat-moss in Sutherland. J. Geikie"'' has given much informa-
tion respecting the Scottish bogs but it will suffice to cite only his
later work. The bogs have yielded many species of trees, all of
them indigenous. The trees are in situ, each rooted in the kind of
soil preferred by living examples. There are few acres of lowland
bog in which trees have not been found. They occur even in the
Hebrides, where trees now are practically unknown. Occasionally,
more than one forest bed is present. At Strathcluony, three tiers
of Scotch fir were seen, separated by layers of peat. Several tiers
were exposed in a railway cutting across the Big Moss ; one of stand-
ing fir trees with branching roots at 6 feet below the surface, a
second at 12 feet and a third at 4 feet lower; so that, counting the
surface growth, four diiferent forests have existed there since the
bog began.

Aher,^-*' in the Bog reports, says that trees in the Irish bogs
" have generally 6 or 7 feet of compact peat under their roots, which
are found standing as they grew, evidently proving the formation
of the peat to have been previous to the growth of the trees." On

^** A. Geikie, " Text-book of Geolog\-," 3d Ed., London, 1893, pp. 478-480.
"' J. Geikie, " The Great Ice Age,'' 3d Ed., London, 1895, pp. 286-293, 303.
'^ Cited by S. S. Haldeman, in 2d Ed. of R. C. Taylor's "' Statistics of
Coal," Philadelphia, 1855, p. 169.

205

608 STEVENSON— FORMATION OF COAL BEDS. [November 3,

the same page Haldeman notes that it is a remarkable fact, although
very common, that successive layers of trees or stumps, in erect
position and furnished with their roots, are found at distinctly dif-
ferent levels, at small vertical distance from each other.

Grand' Eury,^-^ noting that the plants, active in peat-making, are
not the same in all cases, maintains that a distinction must be made
between peat, properly so-called, and peat of the iiiarais. The
former is supraaquatic, covers high plateaus and is formed chiefly
by Sphaynimi, with some other water-loving mosses. Unaccom-
panied by these, other plants in similar conditions give only soil.
Such peat is rarely transformed into a compact charhon and it is
obscurely stratified. The peat of marais is formed on low grounds,
along the borders of rivers, lakes or the sea, often in extensive areas.
In such places, Arundo grows rapidly along with Scirpus palustris
and reeds as well as with Hypnnm, Nymphoca and other semi-aquatic
plants. This peat may be divided by sandy deposits and at the
bottom one finds a muddy peat, almost without structure. It occurs
in Holland and on the shores of the Baltic, the marshes being of
great extent in both regions. Fossil peat occurs at Utznach in
Switzerland.

Still different are the peats of wooded swamps and swampy
forests. In depressed areas, where the forests have been killed by
swamp plants, the peat, formed of herbaceous plants and prostrate
stems, accumulates rapidly. He refers to the wood at Kiogge near
Copenhagen, which the Danish naturalists had regarded as due to
transport ; but Lesquereux had shown that it is in place, the trees
having been overturned by the wind — a condition observed in the
present forests near by. The mass is composed almost wholly of
birch and the upper part consists of empty barks entangled in a mud
or half liquid paste, coming from decomposition of the wood.

Grand' Eury examined in the Ural a peat of swamp-forest origin,
a mass of herbaceous plants and debris of trees. Stumps rooted in
the mass were seen at two horizons in the upper part and others
were scattered below. Many stems and branches lie prostrate and,

"' C. Grand' Eury, " Memoire stir la formation de la liouille," Ann. des
Mines, 8nie Ser., Tome I., 1882, pp. 197-202.

206

J9II-] STEVEXSOX— FORMATION OF COAL BEDS. 609

at tlie bottom, a considerable portion is formed of barks, wood,
leaves and other debris, transported and deposited in the water.
Roots can be seen penetrating the gray clay on which the deposit
rests. On the borders, the peat has not been changed in position
and it is felted and herbaceous. In one part it seems to be composed
exclusively of transported plants, there being barks of flattened
birches ; some laminated portions are formed of humefied epidermis
material.

No reasons are given for assigning a great portion of the mass
to transported material, the matter being taken apparently as beyond
dispute ; but one may surmise that the presence of stumps rooted in
the peat, the prostrate trunks and the fragmentary condition of the
enclosing material ma}- have been for him convincing. Grand' Eury
did not believe that trees would grow in peat and the fragmentary
condition of plant remains was proof that they had been washed in.
The conditions, described by him, are precisely those which are
familiar in bogs, for which no conception of transport is admissible.

The Danish swamps were studied by Steenstrup^-- long ago ; his
grouping resembles that employed by the German students. The
most important is the \\^aldmoor or Skovmose type occupying de-
pressions in Quaternary deposits, often more than 30 feet deep.
Where the area was small, the sides were abrupt and the trees
growing on them eventually fell into the bog. where they have been
preserved. In depressions of great extent, one finds an exterior
wooded zone surrounding an interior or central bog zone. The
latter resembles the Lyngmose, the heather or Hochmoor stage.

The central area of the Skovmose is very regular. It rests on
clay derived from the borders ; above which one finds ordinarily one
and a half to even four feet of amorphous peat, becoming pulpy in
water and containing indeterminable plant remains. The peat is
very pure in normal bogs, but layers of calcareous or silicious matter
are not unknown. A layer of hypnum-peat rests on the amorphous
deposit, 3 to 4 feet thick, containing Finns sylvestris, which grew on
the spot, at times forming a forest on the swamp. The trees were

^" Steenstrup, as summarized by Morlot, Trans, in Ann. Rep. Smithsonian
Inst., Washington, 1861, pp. 304 et seq.

207

610 STEVENSON— FORMATION OF COAL BEDS. [November 3,

stunted and grew slowly amid unfavorable conditions, there being
70 annual rings to the inch ; yet the trees lived for several centuries.
In the larger swamps, two or even three layers of pine stumps are
found, in situ, with their bases and roots well-preserved. As the
surface became higher, and drier, the earlier mosses gave place to
others; SpJiaynnm appeared and, at length, heathers. The pines
yielded to the birches and those to alders, hazel bushes and Corylus.
This succession is found only in the central zone ; the deposit is too
thin on the border.

Weber^-'^ after prolonged study of peat areas in northern Ger-
many, grouped the peat producing plants into ( i ) those which form
the moor; (2) those which grow on the peat; (3) those which love
peat or are bound to it. The best illustrations of the relations of
these groups are in moors which began in post-glacial time and have
continued until now. As the result of his examination, Weber suc-
ceeded in determining the stages in development of the bog and in
determining the part played by the several groups of plants. He
presented a classification which has been accepted by many of the
later students. This will be given in detail as applied to the Scandi-
navian deposits.

Somewhat earlier, Blytt^-* had discovered that in western Nor-
way the typical succession is

Feet.

1. Sphagnous peat, about 5

2. Forest bed, chiefly of Scotch fir.

3. Peat more compressed than that of No. i, about 5

4. Forest bed with oak stumps and myriads of hazel nuts.

5. Glacial deposits.

But in eastern Norway, there are four peat layers -alternating with
three forest beds. In Denmark he finds equally distinct evidence
for successive wet and dry periods. In summing up the conditions
observed in Norway, Sweden and Denmark, he finds record of the
following climatic changes :

'"' C. A. Weber, " Aufbau und Vegetation der Moore Norddeutschlands,"
En(iler. Bot. Jahrb., Vol. 40, 1908, Beibldf., No. 90, pp. 19-34.
'"* Blytt, cited by J. Geikie, " Great Ice Age," p. 495.

208

iQii.l STEVEXSON— FORMATION OF COAL BEDS. 611

1. Arctic freshwater beds, containing Salix polaris. S. reticulata, Betula
nana. etc. A semi-continental climate.

2. Sub-glacial stage, with Betula odovata, Popnlus tremula, Salix, etc.
The moors were wet, the climate humid ; equivalent to the Danish " birch
or aspen period."

3. Sub-Arctic stage, drier, many bogs became dry and were overspread
by forest growth ; Scotch fir (Pimis sylvestris) makes its first appearance.

4. Infra-boreal stage, climate again humid ; the flora of Denmark is
still of true northern type; Pinus sylvestris the common tree.

5. Boreal stage, climate drier and forests overspread the bogs, forming
a root bed ; Corylus and oak abundant.

6. Atlantic stage, climate mild and humid ; Quercus scssi flora abundant
in Denmark and southern Sweden ; this is the Danish " oak period."

7. Sub-boreal stage, drier than the last : many peat bogs dried up and
became forested.

8. Sub-Atlantic stage, bogs again wet and the youngest peat layer was
formed ; this is the Danish " beech or alder period."

9. Present stage, the bogs are drying and are becoming forested.

Stages I to 4 are wanting in the low level bogs of the Scandinavian
coast as that region was still submerged.

The peat deposits of Sweden have been studied by H. and L.
von Post, /\ndersson, Sernander and others, and those of Finland
by Andersson. It suffices for the present to present only the salient
facts as recorded by L. von Post/-^ reference to the work of some
others being deferred to a later portion of this work. A'on Post's
studies were made in the province of Xarke, southern Sweden. His
grouping is essentially the same as that offered by Weber but he
gives details, necessary to the present discussion, not noted by other
students. He finds the following types of deposits :

Limnische. I. i. Allochthonous mineral deposits made in open water: here
are clay, with diatoms, poor in plankton, and clay-gyttja, which is
clay with much plankton and diatoms. 2. Allochthonous organic sedi-
ments, including (a) plankton-gyttja, in open, comparatively deep
water, gray to green, more or less elastic, composed of plankton, algae
abounding; (b) detritus-gyttja, in comparatively shallow water, from
Potaniogeton and Nympha-a, red-brown to yellow-black, granular,
mostly plant debris with some plankton; (c) Schwemmtorf, composed
of plant detritus; (d) Ufertorf. like the last and formed very near
the line of low water. It contains lenses of Lake and of Swamp peat.

^''' L. von Post, " Stratigraphische Studien iiber einige Torfmoore in
Narke," Geol. Forcn. Forhaudi, Bd. 31, 1909, pp. 633-640, 644. 647.

209

612 STEVENSON— FORMATION OF COAL BEDS. [November 3,

II. Autochthonous organic deposits. The Lake peat including (fl)
Phraginites peat, clear yellow, composed of fibrous roots with reeds
and some gyttja; {b) Equisetum peat, like the last in structure, but
the color is coal black.

Telniatische. I. Swamp or Niedermoor peats, including (a) Magnocari-
cetum peat, consisting of sedges with Amblystegium as accessory,
yellow to yellow-brown ; {b) Amblystegium peat, consisting of stems
and leaves of that plant with some sedge constituents; (c) Bruchpeat,
red to black, amorphous humefied peat detritus, in situ, with identi-
fiable roots of sedges.
II. Hochmoor peats, (a) Cuspidatum peat, bright colored Sphagnum
cuspidatum and other water-loving mosses, with remains of Scheuch-
zeria, Carex and Eriophoruin.

Semi-Terrestrische. I. (b) Vaginatum peat, Sphagnum with Eriophorum
vaginatum roots and stalks, these often making up one half of the
mass, humefied and dark colored; (r) Sphagnum peat in lenses with
Cladinti remains between clear brown layers of Sphagnum with
Eyi(iplioru]ii.
II. Forest peat, (a) Alder forest peat, red-black, amorphous, consists
of in situ deposited detritus of an alder swamp forest. Remains of
alder are recognizable; Cenococcum geopliilum abvmdant.

Terrestrische. (b) Birch forest peat, like tlie last, but commonly dark
colored, deposited in a birch swamp forest; (c) Forest peat, rich in
Eriophorum and Sphagnu))i, as a rule, dark colored, almost always with
stumps and other remains of Scotch fir; (d) Forest mould, dark,
composed of wood detritus and grains of humus, witli stumps.

All of these types from Lake peat down are autochthonous. The
upper Hmit of the basin or Hmnic deposits is at the normal Hue of
low water ; the shore or tehiiatic deposits are in the space covered
at high water, while the terrestrial are on forested areas, rarely cov-
ered with water. The alder swamp is the passage zone to the ter-
restrial. Von Post confirms IHytt's conclusions respecting the alter-
nation of dry and humid periods, and shows how, during the less
humid times, forests invaded the peat deposits and in some cases
covered the surface of pure peat with a dense growth. He presents
sections from a number of localities. ( )ne from the Asta moor shows

A. Sphagnum peat, 85 centimeters, with, at 80 centimeters, a mass of
fir stumps rooted in the peat and with coaly matter between the stumps.

B. Strongly humefied cuspidatum peat, 10 centimeters.

C. Sedge peat, 30 centimeters, has much Sphagnum above.

D. Alder and birch swamp forest peat, with small stumps of alder,
birch willow and a great quantity of Cenococcum geophilum, 15 centimeters.

210

I9II-] STEVENSON— FORMATION OF COAL BEDS. 613

E. Shore peat, like transported peat, 25 centimeters, roots of Carex,
Equisctum and Phrag)nifes.

F. Plankton-g>ttja, 40 cm. with remains of infloated Phraginites,
Equisctum. etc., some pollen of Picea in upper portion.

G. Cla}', 50 cm. rich in saltwater diatoms.

As interpreted by Yon Post, one has here at the bottom, a deposit
of plankton tnaterial or Sapropel. It was invaded by the shore peat,
on which a forest of birch and alder grew for a short time amid
unfavorable conditions, as the swamp was overflowed at times ; this
condition became more marked and a sedge swamp followed, in
which Sphagnum gradually gained control. Still later, for a short
period, during which accumulation of peat continued unchecked, the
moor was covered with a dense growth of firs ; but as the moisture
increased, the non-water-loving elements disappeared and a Calluna-
Eriophoniin moor occupied the area. Sections in Skarby lake com-
plex show the same general features as those observed elsewhere in
this region. Though there are dififerences in detail, the story is prac-
tically the same throughout. The open water deposits, gyttjas rich
in plankton material, form the lowest stratum resting on clay or
sand ; on this is the shore peat, which gradually passed across the
basin. Then came the time of decreasing moisture ; alders advanced
on the peat surface, now subject to only occasional overflows ; they
were succeeded by birches, which were rooted in the alder peat ; and
finally came the great forests of Scotch' fir growing in the birch and
alder peat, to be succeeded by Sphagiiitiii-'Hoch.moov peat in the
moist Sub-Atlantic stage. Peat-making was continuous in the for-
ests and each type of forest peat has its own group of minor plants.

Buried Peat Deposits. — Some authors have contended that peat
deposits on the land are not likely to be preserved because, exposed
to air, they must be afifected by atmospheric conditions and eventu-
ally must waste away. Under such conditions, it is certain that
only such accumulations of vegetable material as are deposited in
water-filled basins would be preserved. But the supposed condi-
tions are purely hypothetical and are not in accord with those exist-
ing in nature. Indeed, one looking at a peat deposit, many feet
thick, would have difficulty in conceiving how there could be uni-
formity of conditions for a period long enough to permit wastage

211

614 STEVENSON— FORMATION OF COAL BEDS. [November 3.

of so great a mass, almost impermeable to water after having be-
come thoroughly air-dried. But a priori reasoning is unnecessary ;
for, as Lesquereux recognized long ago, burial of peat bogs is part
of the normal sequence of events.

Dawson^-" has described an early Quaternary bog which he saw
in Nova Scotia. It underlies 20 feet of bowlder clay and pressure
has made the peat almost as hard as coal, though it is tougher and
more earthy than good coal. When rubbed or scratched with a
knife, it becomes glossy; it burns with considerable flame and ap-
proaches the brown coals or poorer varieties of bituminous coal.
It contains many roots and branches of trees apparently related to
spruce.

Areas of peat buried under glacial drift are numerous in the
New England states as well as in New Jersey and some of them will
be mentioned in a succeeding section. Newberry,^^" many years ago,
collected all the observations then available for states west from the
Alleghany mountains. In Montgomery county of Ohio, E. Orton
found a bed of peat, 15 to 20 feet thick, the surface covered with
Sphagnuvi, grasses and sedges. It contains coniferous wood with
bones of elephant, mastodon and teeth of giant beaver ; and it under-
lies 90 feet of gravel and sand. At many places in Highland county
of the same state, wells have reached a stratum of vegetable matter
and, at Cleveland, a " carbonaceous stratum " has been found at 20
feet below the surface. A similar condition exists at Lawrenceburg,
Indiana, as well as at many places along the Ohio ; and J. Collett
reported that, throughout southwestern Indiana, there is an ancient
soil, 2 to 20 feet thick, with peat, muck, rooted stumps, branches and
leaves, at 60 to 120 feet below the surface. This deposit is known
locally as " Noah's cattle yards." The same condition is reported
from a portion of Illinois. The great forest bed of Iowa, discov-
ered by McGee at a later time, is in part a buried bog. Leverett,
Taylor, and Goldthwait have described autochthonous peat bogs
buried under glacial drift at many localities within the Missis-
sippi area.

'"° J. W. Dawson, " Acadian Geology," 2d Ed., London, 1868, p. 63.
'" J. S. Newberry, " Surface Geology of Ohio," Geol. Survey of Ohio,
1874, Vol. IT., pp. 30-32.

212

191 1] STEVENSON— FORMATION OF COAL BEDS. 615

In America, observations as recorded are very few and, for the
most part, they are merely incidental, as until very recently the geo-
logical importance of peat was not recognized ; but in Europe the
case is very different ; one finds there such a wealth of illustration
as to cause surprise that any student should entertain doubts respect-
ing preservation of peat deposits by burial under sediments. A few
citations must suffice.

J. Geikie^-* says that peat bogs often pass below the sea. In the
harbor of Aberdeen, trunks of oak are brought up and at a little
distance away, peat was seen below the sea level covered with lo
to 12 feet of sand. This bed, enclosing trees, is known to extend
for some distance into the bay. In the Carse lands, the river Tay
has cut down to a peat bog, now forming the river bed and under-
lying about ly feet of alluvial material, which near the top contains
cockles, mussels and other marine forms. This extensive peat de-
posit of the wide Carse area rests in part on alluvial sands and in
part on marine clays. The peat is highly compressed and splits
readily into laminze, on whose surfaces are small seeds and wing
cases of insects. As a rule, but not always, it is marked oft' sharply
from the overlying clay and silt. That it represents an old land sur-
face is certain but it is equally clear that, in great part, the vegetable
debris on top was drifted in from localities higher up in the valley,
for the upper part of the peat contains, at times, layers of silt and
twigs, while branches as well as trunks are scattered through the
lower 3 or 4 feet of the overlying silt. The conditions are the same
in Carse lands on both sides of Scotland and they exist in the
Hebrides.

Prevost and Reade'-" have described a peat bed covered by a thick
deposit of sediments. The exposed portion is a dark-brown peaty
mass, containing large and small branches, roots and rootlets, the
latter passing into the underclay. Some large boles and an occa-
sional stump were seen on the upper surface. The authors note as
a remarkable fact, that this bed resists erosive action by the river

'■^ J. Geikie, " The Great Ice Age," 1895, pp. 290-293.

'"^ E. W. Prevost and T. :M. Reade, " The Peat and Forest Bed at West-
bury-on-Severn," Proc. Cottcsicold Xaf. Club, Vol. NIV., 1901.

PROC. AMER. PHIL. SOC, L. 202 OO, PRINTED NOV. IJ, I9II.

213

GIG STEVENSON— FORMATION OF COAL BEDS. [November 3,

as well as by the more energetic bore, so that it projects as a prom-
ontory. Strahan^^" measured the section exposed during excava-
tions for docks on Barry island. The succession is

I. Blown sand, Scrobicularia clay, sand, shingle, with strong line of
erosion below. 2. Blue silt with many sedges. 3. Upper peat bed, i to 2
feet thick. 4. Blue silty clay with many sedges. 5. Second peat bed, thin.
6. Blue silty clay with sedges. 7. Third peat bed. with many logs and
stools, roots in place underneath. 8. Blue silty clays with reeds, willow
leaves and freshwater shells. 9. Fourth peat bed with large trees and roots
in place and numerous land shells. 10. An old soil with roots and land
shells. II. Rock in place, at 35 feet below the Ordnance datum.

Here as in the Carse area of Scotland, the peat underlies a
deposit containing marine shells.

Lesquereux^^^ cites a French author, who found at many places
in the Department of Xord alternations of peat and sand, the latter
containing marine shells. He notes that when the growth of peat
is checked by dryness, a crust forms, which is a parting between the
old and the new peat. In the valley of the Somme.he found, under-
lying 8 feet of clay and concretionary limestone, 23 feet, 4 inches of
peat in 15 layers, with the partings distinct and the layers differing
in character. Alternations of clay, peat and calcareous concretions
are not rare.

Geinitz,^^- more than twenty-five years ago, studied the dune-
covered bogs near Rostock. At a later period he had opportunity
for more detailed examination and his observations are important
from several points of view. At the bathing station near Graal. the
section shows at the bottom, sand of the Rostock plain, on which
rests a one-foot layer of peat, containing stumps of trees which grew^
on it. The dune formerly covering this deposit has been removed
for some distance, exposing the peat, but it still remains at a little
way landward. Beyond the dune, one finds a forest of great beeches
and oaks, with the peat bed covering the surface between them.

""A. Strahan, Mem. Geol. Survey, " (jeology of the South Wales Coal
Field," Part III., 1902, pp. 87-93.

"' L. Lesquereux, Ann. Rep. 2d Geol. Survey of Penn. for 1885, pp. 116-
118.

'^- E. Geinitz, " Nach der Sturmflut," Aus der Natur, Vol. IX.. 1908,
pp. 76-83.

214

19"-] STEVEXSOX— FORAIATIOX OF COAL BEDS. 617

When he looks at the dune surface, he sees, as it were, shrubs rising
out of the sand, some short thick stems of beech and oak ; but they
are not shrubs, they are the still living parts of trees, the same in
age and growth as those standing in the open forest. They have
been buried by the advancing dune. A mighty storm tiood, tearing
away the sea wall and removing part of the dune, will expose vertical
trees standing in the sands as in the Coal Measures sandstones. At
present, one sees advancing masses of sand burying the trees, which
grow on low-lying moors. At another locality, storms, during re-
cent years, have exposed an older peat deposit, underlying the sands
of the Rostock plain. The outcrop extends hundreds of meters
along the shore and shows that the peat is a moss peat, which bore
a forest of Scotch fir. There, as also near Graal, the waves hav^
torn off fragments of the peat and have worn them down into
elliptical form similar to that of the beach pebbles. Barrois^^^ has
referred to similar origin of peat pebbles on the shore of the British
channel, where some neolithic deposits of peat are exposed to the
waves. The fragments of peat are rolled, rounded and eventually
transformed into true ellipsoidal pebbles.

Lorie,^"* in his fifth contribution to the surface geolog}' of Hol-
land has gathered together all the available information respecting
the buried recent peat deposits of that region.

In all probability the Zuyder Zee was filled with peat prior to
the catastrophe of the middle ages, but the only vestige is on the
island of Schalkland, where one finds 5 to 7 meters of peat covered
with a meter or more of marine clay. The same condition exists
on the river Y near Amsterdam and in the province of Zeeland as
well as in the west part of North Brabant in Belgium. The peat
bed near Oudenbosch, in the latter province, is 0.75 meter thick and
underlies 0.65 meter of sediment. It is readily traceable from that
village across Zeeland into western Flanders of Belgium, and thence
to the coast at Ostend in Belgium and Dunkerque in France, a dis-

'^ C. Barrois, " Observations sur les galets de cannel-coal du terrain
houiller de Bruay." Aim. Soc. Gcol. du Xord., Vol. XXXVII., 1908, p. 7.

^^ J. Lorie. " Les dunes interieures, les tourbieres basses et les oscilla-
tions du sol." Archives Mus. Teylcr, 2me Ser., Vol. III., 1890, pp. 424-427,
444. PI. 2.

215

618 STEVENSON— FORM ATIOX OF COAL BEDS. [November 3,

tance of more than 60 miles. Lorie eite.s lielpaire pere, who says
that it is one to 3 or even 4.5 meters thick and that it rests mostly
on blue clay, though in some localities on fine sand. It is double
near Ostend, where the lower bed is black, compact, with roots of
reeds, while the upper bed contains no reeds but has woody fibers,
apparently roots of heath plants. The peat and its overlying clay
are sometimes continuous under the dunes and shore, as is also the
case on the island of Walcheren in Zeeland. Trees, rooted in the
subsoil, occur frequently in the peat. Belpaire fils says that the
thickness of the peat and that of the overl\ing clay vary from i to
3 meters and that the clay level is never above high tide. On the
left bank of the Escaut (Scheldt) as it flows from France across
Belgium the peat is almost a meter and a half thick, but the clay,
2 to 3 meters, decreases as it recedes from the river. Lorie says
that Rutot found a divided peat near Blankenberghe in Belgium.
Reference to Rutot's^^'"' publication shows that the section is

Meters.

1. Shore sand 2.30

2. Gray sandy clay 0.60

3. Gray sand, with bed of Cardium- midway i.io

4. Pure peat 2.00

5. Gray sand, slightly argillaceous 0.40

6. Sandy clay 0.50

7. Gray, argillaceous sand 2.50

The peat underlies a marine sand and overlies a sand which is but
slightly argillaceous.

In 1852, Harting, as cited by Lorie, discovered hard dry peat at
10 to 12 meters below the surface in Amsterdam. Ghyben followed
this eastward toward the Wecht river. For much of the distance,
it is covered with marine sand, but at that river it is covered with
the main mass of peat, constituting the boundary between the sandy
diluvium and the alluvial deposits. In later years it became possible
to confirm and to extend the early observations, for many borings
have been made along railroad lines within the polder areas of Hol-
land. Lorie has tabulated the records of 124 such borings, showing

'^^A. Rutot, " Le puits artesien de Blankenberghe," Bull. Soc. Beige de
Geol., Vol. TI., 1888, Mem., p. 261. This author has given equally illustrative
records in later memoirs published in tjiis Bulletin, Vol. VIII.. 1894; Vol.
XL, 1897.

216

IQII.]

STEVEXSOX— FORMATION OF COAL BEDS.

619

the conditions between Enkhuizen. north from Amsterdam, and
Dordrecht, south from Rotterdam, as well as in localities east and
west from that line. It is unnecessary to give more than a few of
these as in any group the same conditions are found. Eighteen
borings are reported along the east and west line from Rotterdam
to the Hook of Holland. Seven of these follow, the measurements
beinsf in meters and the numbers are those of the records :

Sand and clay 4.5

Peat 0.9

Sand and clay

Peat

Sand and clay

Peat

Sand and clay

Peat

Sand and clay

Peat

S-.
3-9
14

ss.

3-2

30

So.

6.0

1-5

5-1
2.6

0.5
0.3
6.0
i.o

103.

4-5
Z-2
2.5
0.5
0.1

0.5
1-5
1.0
1.2
1.0

These exhibit the variations to a depth of 16 meters. The mate-
rial in each case below the lowest peat bed in the column is sedi-
mentary clay and sand. Peat was found in some localities at 19
meters, but it is never continuous to that depth, being always divided
by sediments. The greatest continuous thickness found in any
boring is 10 meters. At times the peat is replaced wholly by sedi-
ment and one can trace old river courses in which no peat was
formed and which now are filled with the transported sediment.
The records show the conditions in an area of 70 by 20 miles,
throughout which one finds one or more beds of peat covered with
a greater or less thickness of sediment. These are autochthonous,
and they contain stems of trees rooted in the subsoil. The inter-
vening deposits are often distinctly marine in many parts of ?Iol-
land ; a section by Lorie shows

Meters.

1 . Peat 3.2

2. Gray clay, sandy below, calcareous, marine diatoms below,

plant remains in upper part 0.8

3. Argillaceous sand with Cardhim and Scrobicularia .>Q

4. Black peat 05

5. Tough grayish blue clay i.i

6. Black, hardly coherent peat 1.2

217

620 STEVENSON— FORMATION OF COAL BEDS. [November 3.

The portion of Holland considered in Lorie's tabulated records
is not less than 1,500 square miles ; a more extensive area in Belgium
shows the existence of covered peat deposits and this condition
reaches far over into France, for, at Cotentin in Normandy, the
peat, 20 meters thick, is covered with 3 meters of marine sand. One
has in this region an area, almost as great as that of the Everglades
in Florida, in which the existence of buried peat bogs has been
proved, some of them having been traced continuously in a great
part of the region. How great the total area may be, has not been
ascertained, but it is very much greater than that which has been
studied in detail.

The change in structure and composition of peat, as the depth
increases, has been referred to more than once in the preceding
pages. Evidently the older the peat, other things being equal, the
more thoroughly the material is disintegrated, li compacted by
pressure and the removal of water, it assumes the appearance of
brown coal and does not regain plasticity, as appears from the de-
scriptions by Dawson and Lesquereux, to which many others might
have been added. It is certain that some constituent, once soluble
in water, has become insoluble, as soluble silica, once dried, becomes
insoluble. When the deposit, exclusive of enclosed wood, has been
reduced to mature peat, one must resort to chemical reagents and to
the microscope in order to ascertain the component materials. Those
bring to view a structure, a physical composition, which is wholly
similar to that which Grand" Eury gives for coal studied after the
same method. It is a mass of disintegrated fragments, held together
by a fundamental material, much of which was originally flocculent.
The older quaternary peats show much variation ; that described by
Dawson has little which suggests peat to the unaided eye; but there
are others which so much resemble the newer peats that, were it not
for the presence of extinct mammals and the great thickness of
cover, one might hesitate before deciding that they are not of recent
origin. There are still others, which in the several layers exhibit
great variations, some being of comparatively unchanged peat, while
the material in others has lost all of the original macroscopic
features.

218

I9II.] STEVENSON— FORMATION OF COAL BEDS. 621

Among the latter group, the most noteworthy example is the
Schieferkohle of Utznach, Diirnten and neighboring localities in
Switzerland, which is interesting from the economic as well as the
scientific point of view. Having been studied in great detail by
several geologists, it will suffice as type. Some have thought that
these deposits are post-glacial, in which case, they would possess the
greatest possible interest to students seeking to ascertain the mode
in which vegetable matter became converted into coal and gathered
into beds. But the age remains unsettled ; Heim^^*^ maintains that
the Schieferkohle lies between moraines. The section in detail at
Wetzikon and Utznach shows drumlines and erratic blocks of the
last glaciation resting on fluvio-glacial gravels. The lignite, under-
lying the latter, i to 3 meters thick, rests on bowlder clay of the
greatest glaciation. These lignites are autochthonous, full of Betula
alba, the stems at times vertical and with their roots in the under-
lying bowlder clay.

Heer^^' in his earlier work discussed the Utznach and Diirnten
deposits, but dwelt more in detail on the latter as, at that time, it
was the better exposed. The lignite is 12 feet thick, rests on clay
and underlies about 30 feet of sand and gravel. It is not continuous
vertically, but is divided by 6 clay partings, in all about 2 feet. The
lowest bench contains much wood together \\ith cones oi Piiius abies,
which are not found in the upper benches. In each higher bench,
one finds at the bottom, whole layers of mosses, felted together and
pierced by reeds, while above are stems, lying in all directions, with
roots, barks and fragments of wood, all pressed flat. The annual
rings are distinct in many stems and in one Heer counted 100. Some
coaled stems were seen, which he thinks may have been charred by
lightning. The trunks are surrounded as in peat by a black-brown
mass, which undoubtedly originated from decay of herbaceous
plants, converting them into a pulp-like mass. This succession is
repeated in every branch, but, in the topmost, stems are compara-
tively rare, mosses and reeds predominating.

'"^ A. Heim in letter of ^lay 23, 1911.

'^' O. Heer. " Die Schieferkohlen von Utznach und Diirnten." Zurich,
1858, pp. 7-1 1 ; "The Primeval World of Switzerland," Eng. Trans., London,
1876, Vol. L, pp. 29, 30, 32; Vol. IL, pp. 149-155, 157, 161-163.

219

622 STEVENSON— FORMATION OF COAL BEDS. [November 3.

The plants and the conditions arc those of a peat moor. The
mosses belong to the peat-forming group; the reeds and sedges are
swamp plants to which also belongs the bogbean (Mcnyaiithes) of
which the seeds are abundant in both the coal and the partings.
Spruce is present only in the lowest bench but birch and fir (Pimts
sylvcstris) are in the higher benches. The trees are those of the
swamps. The animal remains belong in part to a swamp fauna,
there being great abundance of insect wing-cases on surfaces of the
peat and clay layers, while with them are shells of freshwater mol-
lusks. The larger animals are mammals. Everything goes to show
that this Schieferkohle is a compressed, dried out peat and the older
opinion — that it originated from drifted wood — is incorrect.

In his later work, Heer gives additional facts respecting Diirnten
and some noteworthy observations concerning other localities. At
Diirnten, a wedge of sand and pebbles separates the main mass from
a 6-inch layer of peat and stems above. The main portion is hori-
zontal, while the thin layer dips toward the place of union and the
sands overlying it have the same dip. At Unterwetzikon the lignite,
underlying 12 to 30 feet of stratified sands and gravel, rests on a
marl with freshwater shells. At Utznach, there are two beds, 5
and 3 feet, separated by 16 to 20 feet of light colored marly mate-
rial, and the lignite retains its original horizontal position. At
Morschwyl, the lignite is 2 feet thick, with vertical tree stems, the
whole marly deposit, including the lignite, being 8 feet thick and
underlying 26 feet of detritus. At another locality, the cover is
70 feet and the deposit is 3 feet, with vertical stems, 6 feet high
and 3 feet diameter, extending into the marl above. This lignite
underlies and overlies marl, the whole mass being about 16 feet thick.
Heer gives a list of the plants recognized at the several localities and
discusses their relations, showing that the grouping is clearly that
observed in peat bogs of northern Europe.

V. GiimbeP^^ studied this Schieferkohle from many places in
Switzerland and southern Bavaria, his typical locality being Mor-
schwyl. In l)oth the partly loose peat-like and the partly dense
pitchcoal-like i)ortions, numerous horizontal-lying fragments of

"' C. W. V. Giimliel, " Beitrjige zur Kenntniss," etc.. pp. 135-138.

220

19". J STEVEXSOX— FORMATION OF COAL BEDS. 623

boughs and stems were found, mostly conifers, birches, willows and
alders, which in some cases resemble brown coal, in others, pitch
coal. The peat-like character of the whole mass, as described by
V. Giimbel, recalls the buried bogs of Ohio and Indiana. Treated
with caustic potash, the looser portions become a soft, dense felted
mass, in which the microscope detects as prevailing constituents,
leaves of grasses with mosses. Sphagnum is the prevailing form.
Fragments of wood are comparatively rare, though needles and
twigs of conifers are not wanting. The denser portions need appli-
cation of Schultze's test, a mixture of potassium chlorate and strong
nitric acid, which must be allowed to act for a considerable time in
order to separate the plant remains. These are the same as in the
looser portions. But in addition are splinters of a deep brown
structureless material, behaving as dopplerite. It fills cell-spaces in
many plant-fragments; this textureless material is the Carbohumin.
The numerous cones embedded in the mass are not deformed.

In passing from the Quaternary to the Tertiary, one finds in-
creased difficulty in recognizing peat bogs ; the conditions, observed
in the older portions of recent bogs and in those of the Quaternary,
are intensified by compression and by removal of the water, which
kept in soluble condition the ulmic and humic constituents, while
advancing chemical change has converted the whole mass into the
mature condition. In fine, the amorphous plastic peat has become
amorphous brown coal and only trunks of resistant wood remain to
tell the story. Yet in some cases the resemblance is so great that
little room remains for doubt. A typical instance is the great
Senftenberg Miocene deposit, described by Potonie, to which refer-
ence will be made again on a succeeding page. To one familiar with
the cypress swamps of the United States, there can be no question
respecting the origin of that deposit. Aside from loss in plasticity
of the peat, and its conversion into brown coal, the description given
by Potonie would apply equally well to the white cedar swamps of
New Jersey or to some of the Taxodiuin swamps of the Mississippi,
where the peat is equally pure, the mud and silt having been strained
out as the water passed through cane brakes.

Heer, in his " Primeval World of Switzerland," says that at

221

624 STEVENSON— FORMATION OF COAL BEDS. [November 3,

Diirntcn, the Schieferkohle rests on a gray-white marl containing
Anodonta, ValTata and Pisidinm. That marly clay rests on the Oli-
gocene Molasse, which holds a bed of lignite. The woody limbs are
still distinct but the rest of the mass has been changed beyond recog-
nition. Yet one finds traces of marsh plants in the overlying marls,
while underlying the lignite is an undoubted lake-marl containing
Unio, Planorhis and Lynmcva.

Conclusions. — In this presentation of the features characterizing
peat deposits, some facts appear in notably bold relief.

1. Peat deposits vary in form from lenses to sheets; the former
are of petty to considerable extent, fill depressions such as pond or
small lake basins ; the latter, often of vast extent, originate on ap-
proximately level areas, where drainage is imperfect. The bottom
and top are apt to be irregular ; the latter because of islands or sandy
deposits but especially because of streams and shallow ponds; but
the form of the bottom depends on that of the surface on which it
rests. The thickness may show great variation ; a few inches of
peat at one locality may be continuous with a deposit, 10 or even
60 feet thick elsewhere. Great deposits are not continuous verti-
cally ; partings divide the bed into benches ; those partings may be
very thin, clay or sandy clay with much woody matter, merely desic-
cated peat wasted by exposure during a dry period, or they may be
sediments, varying irom films of clay to beds of sand, gravel or clay,
loose or consolidated. Peat deposits, especially those of great hori-
zontal extent, often bifurcate and, at times, the "splits" reunite.
The underlying material may be clay or sand — usually clay or marl
for the lens-shaped deposits, but very often sand or sandy clay for
sheet deposits extending over great areas. Sand with slight admix-
ture of clay becomes practically impermeable by absorption of
humic acid.

2. Peat deposits are recognized by macroscopic features as far
back as the middle Tertiary. Some of Post-glacial age and several
thousands of miles in extent are buried under 3 to 30 feet of sedi-
ment; some Quaternary deposits underlie 30 to 120 feet of trans-
ported inorganic matter and the overlying deposits vary from fine

222

191 1.] STEVENSON— FORMATION OF COAL BEDS. 625

clay with plant impressions to fine or coarse sandstone, conglomerate
or even breccia.

3. Many vast moors, such as those of the Netherlands and North
Germany as well as great and small moors in the United States and
elsewhere, are at only a few feet above tide. A very slight depres-
sion suffices to bring the surface below that level and to introduce
marine conditions. In lowdand areas, thousands of square miles in
extent, one finds a marine deposit, with characteristic fossils, imme-
diately overlying peat, which is sometimes continuous with a still
living moor above high tide. In such areas, one finds occasionally
a marine deposit, clay or sand, immediately underlying the peat.
The overlying or the underlying material or both of them may be
distinctly calcareous.

4. The passage from peat to the overlying deposit may be abrupt
or it may be gradual through alternations of peat and sediment.

5. The channel ways of streams crossing the moors are traceable
in borings after the moors have been covered with sediment ; they
contain little or no peat.

6. The peat deposit is not always homogeneous. Sapropel, or-
ganic mud, is the foundation in a great proportion of lake deposits
in Europe and in some within the United States ; it is probably
absent at bottom of great sheet deposits ; but it may occur as lenses
in any part of the section, marking the sites of shallow ponds.
Sapropel is an unimportant constituent of true peat, which is pro-
duced by water-loving land plants, the work of other types being a
negligible factor. The several benches of a deposit may difl:'er nota-
bly in structure and composition. Peats are laminated even when
new, but under compression, the lamination is characteristic and the
material has a coal-like appearance.

7. Peat varies greatly in purity. At times, it has less ash than
is found in plants whence it is derived, owing to the action of
organic acids on silica and other mineral constituents ; in most cases
it shows notable variations, both vertically and horizontally, that
variation depending chiefly on extent of exposure to flooding by
muddy waters. Peat often contains a considerable quantity of iron
and calcium in combination with carbonic, sulphuric and phosphoric

223

626 STEVENSON— FORMATION OF COAL BEDS. [November 3.

acids. Alumina and sodium chloride seem to always be present,
though the latter is in small proportion.

8. When mature, peat consists of minute fragments of plants,
embedded in an amorphous substance, more or less flocculent, the
whole cemented b\- an originally soluble substance, which fills clefts
in the peat and at times clefts in the underlying deposit and. in the
older peat, penetrates even the cell tissue of plant fragments.

9. In a very great number of peat deposits, one finds erect stems
of trees, rooted in the underlying clay or sand. Within extensive
areas, the peat mass is crowded with successive generations of trees,
which had grown on the peat, their roots not penetrating to the soil
below. In the case of the less durable woods, the interior has dis-
appeared and the compressed bark remains ; but the prostrated stems
of the more durable or resinous woods have resisted decay and they
have retained their form ; yet in Quaternary peat, the flattening is
more or less marked in all. Peat is not good soil for all kinds of
plants even when dry, but, even when wet, it is the soil on which
several types of majestic trees thrive best ; when somewhat less wet,
it is the habitat of some other great trees, which flourish, while peat
accumulates around their stems.

10. Peat accumulates within the tropics wherever conditions of
topography and humidity are favorable.

11. The deposits of true peat are autochthonous.

Buried Forest.s.

Long ago, erect trees with roots and at times with branches
attached, were observed in the Coal Measures. Some geologists
were convinced that the existence of these trees was proof that coal
beds were formed in situ. The force of this argument seems to be
recognized by some of those who favor the doctrine of origin by
transport, for, in later years, every reported discovery of trees or
forest buried /;; situ has been met with incredulity or worse. The
writer does not share in the opinion that the presence of trees buried
/// loco natali is of serious import as an argument, directly, either
for or against any hypothesis respecting the mode of coal bed for-
mation ; but, in this, he apparentl}' differs from so many geologists,

224

'91'.] STEVEXSOX— FORMATION OF COAL BEDS. 627

that it may be well to supplement the references to buried swamps
by some notes upon buried forests.

Russell's^^" description of conditions on the Yahtse river of
Alaska relates that the stream, issuing as a swift current from
beneath the glacier, has invaded a forest at the east and has sur-
rounded the trees with sand and gravel to a depth of many feet.
Some of the dead trunks, still retaining their branches, project above
the mass, but the greater part of them have been broken oiT and
buried in the deposit. Other streams, east from the Yahtse, have
invaded forests, as is indicated by dead trees standing along their
borders. Where the deposit is deepest, the trees have already dis-
appeared and the forest has been replaced with sand tlats. The
decaying trunks are broken off by the wind and are buried in pros-
trate position. This deposit, consolidated, would resemble closely a
Coal Measures conglomerate.

The submerged forest on the Columbia river of Oregon was
observed first by Lewis and Clark and it was examined almost 30
years afterwards by Wilkes ; but Newberry"" was the first to study
it in detail. ITe found the river bordered at intervals on each side
by the erect but partially decayed stumps of trees, which project in
considerable numbers above the surface of the water. These stumps
belong to the Douglas spruce, which still covers the mountain slopes.
The dam at the Cascades is a conglomerate, penetrated by threads
of silica, often filling cavities with agate and chalcedony. It con-
tains many trunks of trees, some of them merely carbonized, others
silicified, while still others show both conditions. These trunks have
a microscopic structure closely resembling that of the Douglas
spruce. The writer may add that similar conditions exist in the
buried forest near Salem on the Willamette river in the same state.

Along the whole Atlantic coast from Xova Scotia to Florida, one
finds sunken forests now buried under peat or sediments. Dawson
described one seen on the coast of Nova Scotia at 25 to 30 feet
below high tide, where the stumps were rooted in material, having

"' L C. Russell, " Second Expedition to Mount St. Elias," Thirteenth
Ann. Rep. U. S. Geo). Survey, 1893. Pt. I., p. 14, PI. XH.

""J. S. Xewberry, Pacific Railroad Explorations, Vol. VI., 1856, "Geo-
logical Report," p. 56.

225

628 STEVENSON— FORMATION OF COAL BEDS. [November 3,

all the characteristics of a forest soil, and were scattered irregularly
as in an open wood. E. Hitchcock asserted that buried forests are
numerous along the coast of Massachusetts ; cedar, oak, maple and
beech trees are found in the harbor of Nantucket, some erect, others
prostrate and all of them surrounded by an imperfect peat. This
forest is buried under 4 feet of sand. Cook^" has described many
buried forests in New Jersey, the most interesting being those now
concealed under the tidal mar.shes. At one locality, a ditch was
digged to drain some large tidal ponds ; it exposed nothing but mud
and grass roots ; the outrush of water at ebb tide widened this narrow
drain to 70 feet and scoured the bottom, which proved to be thickly
set with pine, white cedar and gum stumps, standing upright and
giving every indication that they were where they had grown.

Tuomey^*- has described an area of tidal marsh, which is covered
with live-oak trees, some standing, but most of them prostrate.
These are certainly not where they grew and it is equally evident
that they have not been transported. Originally this mud flat, now-
littered with shells of oysters and mussels, was covered with sand
hills, of which some remain. During storms, waves broke over the
peninsula, washed away the sand hills and left the trees, some of
which remain standing because supported by their broad roots. At
another locality, a great white cedar swamp shows living trees, but,
toward the river, the trees are dead and the continuation of the mass
under the river shows stumps in place. Encroachment of salt water
killed the dense undergrowth of the swamp — decomposition of the
exposed peat advanced and the trees broke off at the " air line." He
refers to many places where the saltwater invasion and subsequent
change in the swamp material caused destruction of the white cedar
or cypress forest ; sediment covered the stumps and another growth
followed.

Agassiz,^'^ observed a submerged forest at the mouth of the
Igurapi Grande, which clearly belongs to the recent epoch.

'"G. H. Cook, "Geology of New Jersey," 1868, pp. 350, 352, 354. 355, 360.
"'' M. Tuomey, "Report on the Geology of South Carolina," Cohimbia,
1848, pp. 194-200.

"'L. Agassiz, in "A Journey to Brazil." Boston, 1868, pp. 434. 435.

226

I9II.] STEVEXSOX— FORMATION OF COAL BEDS. 629

" Evidentlj- this forest grew on one of those marshy lands constantly
inundated, for between the stumps is accumulated the loose felt-like peat
characteristic of such grounds and containing about as much mud as vege-
table matter. Such a marshy forest, with the stumps of the trees still stand-
ing erect on the peat, has been laid bare on both sides of the Igurapi Grande
by the encroachments of the ocean. That this is the work of the sea is
undeniable, for all the little depressions and indentations of the peat are
filled with sea sand and a ridge of tidal sand divides it from the forest still
standing bej'ond. X'or is this all. At Vigia, immediately opposite to Soure.
on the continental side of the Para river, just where it meets the sea, we
have the counterpart of this submerged forest. Another peat bog, with the
stumps of innumerable trees standing in it and encroached upon in the same
way by tidal sand, is exposed here also."

Forests buried during the recent epoch are such famihar and
commonplace features that further reference to them is unnecessary.

Forest beds of Quaternary age have been reported by observers
in many parts of the world. Reference has been made already to
the great forest bed of southwestern Indiana, buried under 60 to
120 feet of later glacial material. AIcGee^*^ has described a forest
bed, which divides the glacial deposits in northeastern Iowa. It
was much disturbed during a later advance of the ice. Accumula-
tions of logs, stems, grasses and peaty soils occur at many horizons
in both the upper and the lower till, but they are in largest volume
and least disturbed condition at the junction of the two drift sheets.
The distribution is related to that of the upper till. Where the
glaciation was most energetic, the deposit is absent ; where less ener-
getic, it is present but broken up badly ; toward the eastern part of
the area, the disturbance decreases and the deposit is found in normal
condition with everything in situ. There one finds the peaty soil
with stumps and roots all evidently in place.

Quaternary forest beds are many in Europe. It suffices to quote
from J. Geikie,^^° who has described the condition in Great Britain.

" The broad facts then are these : at a depth from the surface, varying
from 20 to 60 or 70 feet, occurs a layer of peaty matter enclosing and
covering forest trees, the stools of which are often rooted in an ancient
soil. Above this buried land surface appear lacustrine, or estuarine or, as

^^ W J ]^IcGee, " The Pleistocene History of X'ortheastern Iowa,"
Eleventh Ann. Rep. U. S. Geol. Survey, 1891, Pt. I., pp. 199-577. Citations
from pp. 486-496.

"' J. Geikie, " The Great Ice Age," 3d Ed., p. 405.

997

630 STEVENSON— FORMATION OF COAL BEDS. [November 3,

the case may be, marine deposits. Next comes a second forest layer, over-
laid by similar accumulations. It is the second forest bed, which is so fre-
quently exposed upon the present fore shores."

In succeeding pages this author gives detailed evidence respect-
ing the stratigraphic relations of forest beds at the different localities.

Passing from the Qnaternary to the Tertiary, one finds less fre-
quent notices of buried forests, owing, of course, to lack of expo-
sures. Lvell,'^" after describing the btiried cypress swamps of the
Mississippi delta, mentions the Tertiary deposits at Port Hudson,
which had been seen by Bartram and, at a later date, described by
Carpenter. Bartram observed that the erect cypress stumps seemed
to be rotted oft' at 2 or 3 feet above the spread of the roots and that
their trunks, limbs, etc., lie in all directions about them. When
Lyell visited the locality, the water was too high to permit study of
the lowest part of the section and he gave Carpenter's statements
respecting it. At the bottom of the bluff, is a buried cypress swamp,
containing sticks, leaves and fruits in horizontal laminse, with filmy
layers of clay interposed. With these are great numbers of erect
stumps of the large cypress, sending roots into the clay below. At
12 feet higher is a second deposit, 4 feet thick, consisting of logs and
branches, half converted into lignite, along with erect stumps.
Above this are more than 50 feet of clays, containing two layers of
vegetable matter.

Hilgard^'*' gives some details respecting what is evidently the
lower Port Hudson bed as seen between that place and Fontania.
The section in the bluff is

Feet.

1. Yellow loam 8 to 10

2. White and yellow hardpan 18

3. Orange and yellow sand 8 to 15

4. Greenish or bluish clay 7

5. White silt or hardpan 18

6. Green clay with calcareous and ferruginous concretions,

sticks and leaf impresions 30

7. Brown muck or blue clay with cypress stumps 3 to 4

""C. Lyell, "A Second Visit to the United States," etc.. Vol. II., pp.
134, 178, 179, 180, 192, 272, 273.

"' E. W. Hilgard, " On the Geology of Lower Louisiana," Smilhson.
Contrib. No. 248, 1872, pp. 5-7, 9, 11.

228

i9'iJ STEVEXSOX— FORMATION OF COAL BEDS. 631

" These stumps evidently represent three or four successive genera-
tions, growing at higher levels as the surface of the swamp was
raised by deposition." Some of them are large and the wood is so
hard that it is difficult to detach a piece with the hatchet. No. 5,
in some places, is a river alluvium and at times resembles a sandbar.
It frequently contains great quantities of driftwood.

The cypress stumps in Xo. 7 are well preserved and hard, but
the driftwood in Xo. 5 is soft and spongy. When water-soaked and
resting on the ground it is visibly flattened by its own weight ; one
stroke with the hatchet will sever a trunk, 20 inches or more in
diameter. But if this soaked material be exposed to continuous
sunshine, it not only loses water but also contracts into hard shining
lignite, with conchoidal fracture and exhibiting to the eye scarcely
a trace of the original structure. A trunk, 6 or 8 inches in diameter,
when thus dried, forms a contorted coal layer not more than half
an inch thick. The exposed portion of a trunk may be transformed
in this way, while the portion, remaining embedded, retains the orig-
inal features. These changes are very like those seen in the lignite
at Putznach as described by Bischof ; there is evidently a change
from soluble to insoluble in some constituent of the trunk. Hilgard^*®
had traced the deposit underlying the Orange sands through a great
area in southern Mississippi and the features seem to be the same
throughout. It " cannot be better described than as the soil of a
cypress swamp, with its muck, fallen trunks, stumps, roots and
knees. Of these there are evidently several generations, separated
by more clayey layers of muck."

Eldridge"^ mentions a deposit of Eocene lignite in Alaska con-
taining 10 to 15 beds varying in thickness from 6 inches to 6 feet.
The ash is from 1.85 to 10.68 per cent. The lignite of these beds
resembles a mass of carbonized wood. Stumps, i to 2 feet in diam-
eter, are common, standing vertical to the bedding. Their appear-
ance as well as the abundance of slivers and other carbonized

^** E. W. Hilgard, "Report on Geology and Agriculture of the State of
Mississippi," Jackson, i860, pp. 152, 153, 155.

"" G. H. Eldridge, "Reconnaissance in the Sushitna Basin, Alaska,"
Twentieth Ann. Rep. U. S. Geol. Surv., 1900, Pt. VII., pp. 21-23.

PROG. AMER. PHIL. SOC. , I.. 202 PP, PRINTED N(JV. 17, I9II.

229

632 STEVENSON— FORMATION OF COAL BEDS. [November 3,

material suggests that these coal beds originated in a mass of de-
cayed swamp vegetation. Locally, portions of the mass have lost
the woody structure and resemble the higher grades of lignite, shad-
ing into bituminous coal. But, as a whole, this coal is in its youth
and Eldridge thinks it doubtful if a younger example of coal can
be found — peat excepted.

Darwin^^" saw in Chili a petrified forest in Tertiary rocks.
Eleven trunks were silicified and 30 to 40 were converted into
coarsely crystallized white calcareous spar. They had been broken
off abruptly, the vertical stumps projecting a few feet above the
ground. They were from 3 to 5 feet in circumference. "The vol-
canic sandstone, in which the trees were embedded and from the
lower part of which they must have sprung, had accumulated in
thick layers around their trunks ; and the stone yet retained the
impression of their bark."

The ]Miocene brown coal deposit at Gr. Raschen near Senften-
berg has been referred to on a previous page : Potonie's^^^ descrip-
tion is that of a buried forest closely resembling those of New Jer-
sey. It is very similar to the buried cypress swamps and forests of
the southern United States, for Taxodium disticHum is the dominant
tree. As in the white cedar and cypress swamps, one finds in this
brown coal deposit. 10 meters thick, successive generations of trees.
The fuel is mined in open cjuarry and Potonie's plate shows the erect
stumps distributed on the surfaces of several benches as they stood
in the old forest, while the walls of the benches exhibit prostrate
trunks in the intervening spaces, precisely as one sees them now on
the surfaces of the forested swamps in America. These stumps,
one third of a meter to nearly 4 meters in diameter, are, like those
described by Cook and others, rooted in the peat, now converted into
brown coal of excellent quality, as good as that which will come
from the Dennisville peat in New Jersey.

There are few recorded observations of buried forests in the
Mesozoic rocks ; in very great part, those rocks were marine : The

^^" C. Darwin, " Journal of Researches," New York, 1846, Vol. II., pp. 85.

'^' H. Potonie, " Ueber Autochthonie von Carbonkohlen-Flotzen und des
Senftenbergcr Braunkholen-Flotzen,'' Jahrb. k. preuss. geolog. Landesanstalt.,
1895, Separate, pp. 19-24.

230

I9II-] STEVEXSOX— FORMATION OF COAL BEDS. 633

latest Cretaceous in the United States is mostly of freshwater origin
and it contains many coal beds ; but there is no positive evidence that
buried forests exist. Long ago, the writer saw, in New Mexico,
great numbers of stumps and trunks in a sandstone, apparently of
this age, and the same deposit has been mentioned by others ; but
there is no evidence on record to show that the stumps are i)i situ.
Lyell was convinced that he saw vertical stems of Equisetites in
place at a locality in the Triassic field near Richmond, in Virginia,
but his observations are not sufficiently in detail to justify one in
accepting them as evidence. It has been suggested that slender
stems such as those of Equisetnin or Calamitcs could not stand,
while a sandstone accumulated around them ; but the suggestion is
without basis. The writer has seen slender canes on the Gulf shore
of the [Mississippi delta, which had been killed many years before by
an invasion of salt water ; but they were still erect, though sediment
had accumulated around them to the thickness of several feet.

The " dirt bed " of the isle of Portland, belonging to the Upper
Jurassic, was described long ago by Mantell.^"" The uppermost
Oolite stratum is a layer, one foot thick, of very dark friable loam,
which seems to have been a bed of vegetable mould. It contains a
large proportion of earthy lignite and also, like the modern soil of
the island, waterworn pebbles and stones. This is the " dirt bed "
of the quarrymen and upon it are branches and stems of conifers
and plants allied to Cycas and Zamia. Many of the trees and plants
stand erect as if petrified while growing undisturbed in their native
forests. Their roots extend into the " dirt bed " and their trunks
into the superincumbent limestone. At the time of Mantell's visit,
a large area had been exposed by stripping :

" Some of the trunks were surrounded by a conical mound of cal-
careous earth, which had evidently, when in the state of mud, accumulated
around the stems and roots. The upright trunks were in general a few
feet apart and but 3 or 4 feet high ; they were broken or splintered at the
top, as if the trees had been snapped or wrenched off at a short distance
from the ground. Some were 2 feet in diameter, and the united fragments
of the prostrate trunks indicated a total length of between 30 and 40 feet.
In many examples, portions of branches remained attached to the stems."

^^' G. A. Mantell, "Geological Excursions Around the Isle of Wight," 3d
Ed., London, 1854, pp. 287, 288.

231

634 STEVENSON— FORMATION OF COAL BEDS. [November 3,

Green/^^ visiting the locality some years afterward, remarked
that the conditions recall those in interglacial buried forests of
Great Britain ; for the " brashy " soil, containing the stools of large
trees, with here and there prostrate trunks, underlies a limestone
carrying estuarine fossils. Other " dirt beds " appear occasionally,
showing that the condition was repeated at some localities.

Passing to the Palaeozoic, one finds many references to forests
and trees buried in place, for excavations and explorations are ex-
tensive and the localities, unlike most of those in the Mesozoic, are
in regions where scientific observers abound.

Al. Brongniart^^* saw at the mine du Treuil, near Saint-Etienne,
a sandy bed, 10 to 13 feet thick, containing "a true fossil forest of
monocotyledonous vegetables, resembling bamboo, or a huge Eqiti-
setum, as it were, petrified in place." These are erect. There were
two types of stems; one cylindrical, jointed, striated parallel to their
edges and the cavity filled with rock like that which surrounds them.
The rarer forms are hollow cylindrical stems, diverging at the lower
end " after the manner of a root but without presenting any ramifi-
cation." Gruner'""^ notes the existence of another forest at the same
mine, but much lower in th.e section. The trees are Syriiigodcndron
and the roots rest on the coal. Brongniart refers to other localities,
where vertical stems had been seen, and he cites Charpentier, who
explained one rather notable case as due to landslides. Support for
this conception was found in the debacle of Lake Bagne, during
which great trees were carried down with the mass and deposited in
the original vertical condition position on the plain of Martigny.
But Brongniart maintained that such occurrences must be rare,
whereas vertical stems are found at many localities. At Treuil, as
well as near Saarbruck, one finds not merely a single large trunk
but many — a forest of slender stems, which have preserved parallel-
ism among themselves. It is perhaps more difficult to conceive that
sandy rock could envelop them after removal without destroying

''^A. H. Green, "Geology," Fart L, London, 1882, pp. 252, 253.

^"Alex. Brongniart, "On Fossil Vegetables Traversing the Beds of the
Coal Measures," Ann. des Mines, 1821. Trans, by H. de la Beche in "A
Collection of Geological Memoirs," 1836, pp. 210, 216.

'" L. Gruner, " Bassin houiller de la Loire," 1882, p. 226.

232

1911] STEVENSON— FORMATION OF COAL BEDS. 685

them, than to conceive that the deposit was made between them
where they grew and were firmly rooted.

The discovery, near Manchester, England, of erect stumps, led
several members of the London Geological Society to visit the local-
ity. Hawkshaw^^'' in 1839 and 1840 described five erect stumps
and he was firmly convinced that they were in the place of growth.
Bowman^^' in discussing the same occurrence, asserted that the loss
of roots in the ^Manchester specimens was due to a process of fer-
mentation. He combatted the notion that floated trees would remain
erect, maintaining that, when they ceased to float, they would turn
over. Several years afterward, Beckett and Sparrow^^^ discov-
ered some erect stumps near Wolverhampton, England. Beckett
removed the coal attached to one of the trees. The stump was per-
fectly " bitumenized "' but broken oft' at about 2 inches above the
top of the coal, the inner portion being hollowed out to about the
level of the coal. The stem was not flattened ; it was approximately
4 feet in circumference and the roots spread out in a broad mass.
The trunk and roots were covered with one half inch of bark, con-
verted into brighter, more compact coal than that of the interior
which was a mixture of coal and shale. The coal bed is about 5
inches thick. A few years later, Jukes^^^ visited this locality with
Beckett and, in writing about the stumps, he conceded that " they
certainly looked as if they had grown there, and perhaps they may
have done so, but even so, it by no means settles the question" [of
origin of coal beds].

Beckett expressed no opinion respecting the original relations of
the forest, but his paper is followed directly by Ick's^''° description,
which is more in detail. The surface of the coal had been exposed
by stripping in a rudely triangular space of about 2,700 square yards.
Upward of 70 stumps were seen on this terrace, some of them more

^^'' J. Hawkshaw, Proc. London Gcol. Soc, Vol. III., pp. 140, 269.

'"'J. E. Bowman, Ibid., pp. 270, 271, 274.

'"" H. Beckett, Quart. Journ. Geol. See. Vol. I., 1845, pp. 41, 42.

'='J. B. Jukes, "The South Staffordshire Coal-field," 2d Ed., 1859, p. 201,
footnote.

^°"W. Ick, "A Description of Numerous Fossil Dicotyledonous Trees at
Parkfield Colliery near Bilston," Ibid., pp. 43-45.

233

636 STEVENSON— FORMATION OF COAL BEDS. [November 3,

than 8 feet in circumference, all broken off close to the coal, while
the prostrate trunks lie across each other in every direction. These
trunks, 15 to 30 feet long, are invariably flattened to the thickness
of one or two inches, but the bark is distinct on both sides. The
bark is well preserved on the stumps, converted into bright coal,
while the interior or woody part is dead looking, wath dull luster
like cannel. The stumps seldom rise above the surface. In some
cases the diverging roots can be followed for nearly a yard, but they
cannot be traced into the underlying shale. In some cases, Cala-
mites are crowded between the trunks ; Lcpidodendron and Lepido-
strohi are abundant on the surface, while among them one finds occa-
sional remains of fishes. A noteworthy feature is that there are
three coal beds within a vertical space of 12 feet, each of which
shows on its surface the remains of an ancient forest — and the same
beds are exposed a mile away. Beckett says that the coal, when
"broken with the grain," shows faint impressions of Calaiuitcs and
reed-like plants. Ick recognizes that " the position of the trees in
each bed of coal seems almost to preclude all doubt of their having
grown and perished on the spot where their remains are now found,
and the roots are apparently fixed in the coal and shale, which was
the original humus in which they grew."

Binney^*^^ described the great SigiUaria stump, discovered at 7
miles east from Manchester and now in the museum of Owens col-
lege. The stump is filled with dark-colored fireclay but the roots
with a different material. The dark fireclay floor was penetrated
to about 3 feet by the stem and roots, the latter being, in part,
directed upward. ,

De la Beche^''- remarks that actual observations of rooted stems
are comparatively few because exposures are few. He and W. E.
Logan saw many vertical stems in a sandstone at a Welsh colliery.
The directly underlying shale contained ferns and leaves of other
plants distributed " around in the same manner as leaves and other
parts of plants may be dispersed around stems of trees in muddy

'" E. W. Binney, " Description of tlie Dirkenfield SigiUaria,'' Quart.
Journ. Geol. Soc, Vol. II., 1846, p. 390.

""H. T. de la Beche, "The Geological Observer," Philadelphia, 1851,
pp. 482-485, 4Q7-

234

I9II.] STEVENSON— FORMATIOX OF COAL BEDS. 637

places at the present day." The sandstone lamin?e, by their arrange-
ment, suggest the washing up of sand around stems in shallow water
with small waves. This is shown more clearly at a locality in the
Newcastle district, where one can determine the direction whence
the current came by position of laminae marking eddies behind the
stems. Prostrate stems, often of same species with the vertical
stumps, recall the prostrate trees among stumps in " submarine or
sunken forests."

Dawson^*^^ first visited the South Joggins region in 1852, accom-
panied by Lyell. Somewhat later, he studied the section in great
detail and gave his results in a series of memoirs published by the
London Geological Society ; but the final discussion appeared in the
second edition of his Acadian Geology. Seventy coal horizons, some
of them merely " fossil dirt beds," were seen in a vertical section of
4,700 feet and besides these there are many horizons at which rooted
stumps were seen. Drifted trunks were observed in the sandstones,
but those are neglected here, reference being made only to such
remains as were associated with Stigmarian underclays.

Erect stumps were seen in the thin shale roof of Coal 13. In
the interval of 38 feet -between Coals 16 and 17 are several Stig-
marian clays, one of which supports large stumps of SigiUaria with
plant remains about their foot ; the red shale roof of Coal 19 shows
an erect SigiUaria, while erect Calauiitcs stems are present over Coal
21 and a Stigmarian soil at some distance below Coal 22 bears a
number of erect SigiUaria stumps. Division IV. shows erect stems
of SigiUaria, Lepidodcndron and Catamites at 44 horizons in a ver-
tical section of 2,539 feet ; several of the underclays, bearing erect
stumps, underlie thin coal beds and, in at least one case, Coal 15, the
erect stumps are associated with rain marks and footprints, clear
evidence of sub-aerial position. At one horizon, the stumps yielded
three species of batrachians with land shells and insects ; those
stumps are rooted in coaly shale forming the roof of a coal bed.
" A coaly stump and an irregular layer of mineral charcoal, arising
apparently from the decay of similar stumps " were seen in Coal 33a,
while above that bed in a reddish shale is "a patch of gray sand-

^'^J. W. Dawson, "Acadian Geolog>'," 2d Ed., London, 1868. pp. 150-179.

638 STEVENSON— FORMATION OF COAL BEDS. [November 3,

Stone, interlaced with Stigniaria roots, as if the sand had been pre-
vented from drifting away by a tree or stump." The Millstone Grit,
in three divisions and somewhat less than 6,000 feet thick, shows
erect Sigillaricc in the lower portion, but most of the stems occurring
in the sandstones are clearly driftwood.

One must keep in remembrance that Dawson's observations were
made on the outcropping face of the beds along the coast; one may
only conjecture what might be seen if some of the old soils were
stripped as was the coal at Parkfield colliery.

Robb^''* described the rooted stump of Sigillaria, seen by him in
the roof of a coal mine. The roots cross the slope, which is 11
feet wide ; the conditions are shown well in the plate accompanying
his report. He observed many Sigillaria stumps with their attached
roots reaching into the coal seams. He notes one case, where a coal
parting contains the roots of an erect tree, " which had apparently
forced the layers asunder, 6 or 8 inches, for several feet from the
extremities of the roots, beyond which the layers of coal unite
again." In another, " where a large upright stem appears rooted
in a coal seam, the latter seems to have been actually bent down
by the superincumbent weight and, at a little distance, to have re-
sumed its normal attitude."

Gosselet studied^*''"' the occurrence of erect stems at various levels
in a vertical section and discussed their bearing upon the formation
of coal beds. At Lens, there are three coal horizons within a ver-
tical distance of 42 meters — Alfred, Leonard and Louise, with thick-
ness respectively of 1.4, 1.6 and 0.6 meter. In the one meter thick
shale under the Alfred, overlying an irregular passce, he saw two
trunks, one resting on the passce, with the underlying coal slightly
depressed, while, above, it terminates abruptly in a faux-mur, 5
centimeters thick, in direct contact with the coal. No roots could
be traced. Five trunks were seen in the Leonard ; one evidently
had been floated in and a second was too indefinite for determina-

'** C. Robb, Geol. Surv. Canada, Rep. I'rogress, 11^74-5, pp. ig6, 20.3, 204,
23s, 237.

'"J. Gosselet, "Note sur les troiics d'arlires verticaux dans le terrain
houiller dc Lens," Ann. Soc. Gcol. du Xord., Vol. XXI IL, 1895, PP- I74. 1/5.
177-179, 181.

'9II-] STEVEXSOX— FORMATION OF COAL BEDS. 639

tion. Of the other three, two were implanted in a thin mur-like
deposit covering the coal ; the roots of one, a SigiUaria, spread out
in the clay, but the roots of the other could not be traced. The
roots of the third, in the coal, could not be recognized as Stigmaria,
but they extended horizontally as clay masses covered with coal.
The roots had been filled with sediment. Eight stems were seen in
the Louise. Three rose directly from the underlying shale and
crossed the mur, which is 60 centimeters thick ; one was cut off
abruptly at the coal and the others were broken off just before
reaching it. The remaining five are in the roof. One is indefinite,
but the others expand at the base and their rootlets are put forth
into the shale. These erect trees, throughout, were in situ; all were
vertical to the bedding. If they had been transported, they would
have been inclined in direction of the current. Transported trunks
were seen at various horizons but, in the cases described, the trunks
were fixed in place by their roots, wherever the roots were seen.
This Lens locality is in the great W'estphalia-France-Belgium field,
a paralic area.

Gosselet refers to conditions in the Banc des Roseaux at Com-
mentry, where trunks are seen arranged in all directions, vertical,
inclined, prostrate, and he compares them with those resulting from
ravages of a hurricane in the forest of ]\Iormal. There, many of
the trees were prostrated ; some, held by their roots, were inclined ;
while a small number remained erect — the conditions bearing re-
markable resemblance to those observed at Commentry. His con-
clusion is that, where one sees the mur rich in rootlets of Stigmaria,
he may regard it as a soil in which trees spread their roots. If the
tree does not rise above the mur, it is because it has been destroyed
by carbonization to furnish its elements, in part at least, to the coal
bed. When the trunk is cut off sharply at coal or mur, it may be
that the deposits were made so slowly that the trunk rotted off" at
the water-surface. He quotes Fayol as showing that at times one
may prove the presence of erect trunks in the coal itself, but usually
they are fused with the mass.

In this connection, it is well to recall the fact that Potonie^'^'^

'"" H. Potonie, " Die Entstehung der Steinkohle," etc., 1910, pp. 134-136.

237

6i0 STEVENSON— FOR^IATION OF COAL BEDS. [November 3.

found frequent occurrence of Stigniaria in situ at Commentry. One
notable discovery was that of a stump, whose roots spread out in
an area of 6 meters diameter and retained their minute appendages.
According to Renault, the branches extended farther but they could
not be followed. Fig. 46, copied from Renault's description, justi-
fies Potonie's remark that, if this be a transported tree, one must
believe that it and the fine mud enclosing it had been transported
together and deposited in the original position.

Schmitz^'^' examined ^,2, erect stumps exposed in the roof of the
Grande Veine of the Liege basin. The coaly crust, sometimes one
centimeter thick, and the scars suggest that the plants are Sigillaria.
The stumps are in a space of 2 by 95 meters, giving for each plant
5.6 scjuare meters, a condition favorable to the belief that they are
in loco natali. But he found that the trunks are all cut ofif at the
coal bed ; most of them show the enlargement belonging near the
roots, so that one cannot suppose that the trees extended downward
through the coal to the mur. On the other hand, the transition from
coal to sterile rock above is barely one centimeter of coaly clay, so
that they could not have been rooted in the toit. The laminae of
this faux-toit contain many impressions of twigs of lycopods and
Eqiiisctitcs. Four of these pass under the bases of four erect
trunks. This led Schmitz to think it impossible that the trunks
were in loco natali ; for if those four were not, there is no reason to
suppose that the others were. To explain the condition, one must
invoke transport. But, in a later paper to be considered in another
connection, he gives the results of a more detailed study, which led
him to recognize that the abrupt cutting ofif at the base was due to
slips, which explained the presence of plant impressions under the
ends of the free trunks.

Grand' Eury^°* summed up the results of his long study in a
memoir presented at the Paris meeting of the Geological Congress,

^"^ G. Sclimitz, " Un banc a troncs-debout aux charlionnages du Grand-
Bac," Bidl. Acad. Roy. de Belgique, 3me Ser., Vol. XXXI., 1896, pp. 261-264.

^*' C. Grand' Eury, " Sur les tiges debout, les souches enracinees, des
forets et sous-sols des vegetations fossiles et sur le mode et le mecanisme
de formation de couches de houille du bassin de la Loire," C. R. Cong. Geol.
Intern., 1900, Vol. L, pp. 523-530.

238

19"-] STEVEXSOX— FORMATION OF COAL BEDS. 641

drawing his illustrations mainly from conditions in the Loire basin.
He exhibited twelve charts showing rooted trees and stumps discov-
ered near Saint-Etienne during the preceding decade. Trees and
stumps with roots attached were found belonging to Stigmaria,
Syringodcndron, Stigniariopsis, Sigillaria, Calaniites, Calamoden-
dron, Psaronius, CoracAtes and other forms. In several cases, the
leaves still remained attached. The arrangement of the roots de-
pended somewhat on the soil in which they grew. Many times the
more yielding soils permitted the roots to grow downward while in
clays they tend to spread horizontally. Roots of Stigmaria, usually,
those of other plants, frequently, are interlaced in such manner as
to leave no room for doubting that they are in loco natali. The
soils of vegetation are distinct, for the roots are woody, herbaceous,
or of several kinds, occurring in groups or singly, often interlaced,
sometimes spaced but never scattered. They are therefore in place.
Where there have been successive generations, the roots of the
newer generations sometimes penetrate the stumps of their prede-
cessors and in many cases pierce impressions of plants lying in the
shale, through which they pass. The secondary roots of several
types are thoroughly distinct at varying levels, while the creeping
rhizomas at the base still remain attached to the stem ; and one often
finds buried at the foot of rooted trees the branches, leaves and
fructifications which were detached during their growth.

Grand' Eury's conclusion is that Carboniferous plants were ar-
borescent marsh forms, living as those in the Dismal Swamp, the
foot and adventive roots in the water, with the stock and rhizomas
creeping on the bottom. They could live either on the area of in-
creasing deposit or in stagnant water. The fossil forests have no
continuity ; they disappear in all directions, often being reduced to
mere groves.

It is unnecessary to give further illustration. One desiring to
pursue the matter will find in Goeppert's " Prize Essay " a full state-
ment of all information available at that time for eastern Germany,
with full discussion. His studies, in some respects, are as inter-
esting as those by Grand' Eury. Lyell, R. Owen, Lesquereux and
Newberry have given examples for the United States.

239

642 STEVEXSOX— FORMATION OF COAL BEDS. [November 3.

The occurrence of drifted logs and clumps of vegetation is a
phenomenon as familiar as that of buried forests ; indeed, in the
nature of the case, it is more familiar, as coarse rocks are more
widely spread than are the coaly deposits. The battered snags of
the Missouri-Mississippi and the logs scattered through the delta
silts ; the similar accumulations in tertiary deposits of the Missouri
and Mackenzie ; in the London Clay and on the New Siberia islands ;
the irregular pots of lignite in many places on the continent of Eu-
rope; the driftwood in our Newark formation; and the vast abun-
dance of snags, logs and branches in sandstones of the Coal Meas-
ures in Europe and America ; all bear witness, as do the buried
forests, that conditions have undergone no material change since the
closing epochs of the Paljeozoic. These drifted materials are every-
where distinguishable from plants buried i}i situ, for they have been
deprived of all tender parts ; of the harder woods in Carboniferous
times there are few traces except decorticated stems, casts of the
interior, indeterminate forms grouped under Kiiorria, Stcrnhcrgia
and some other names.

Conclusions. — It is strange that there should be such intense un-
willingness to accept evidence in favor of the existence of ancient
forests. Reasoning from existing conditions, one would have room
for disappointment if such forests were not discovered in the older
rocks; yet some authors seem to believe that one is chargeable with
overcredulity if he regard buricfl stumps as rooted in place when
they occur in the Coal Measures and his proof is demanded as
emphatically as though he had asserted that man's normal position
is with his head on the ground and his feet pointing skyward. The
abrupt termination of stumps on the coal and the absence of roots
are, for some, positive evidence that the trees are not in loco natali,
though the condition is that which must come about in the cypress
swamps of this day; the number of prostrate trunks predominates
over that of erect stumps, and this is taken as evidence that all alike
were transported ; yet every great forested swamp shows that broken
and overturned stems fall to be preserved in moist surrounding,
while manv stumps remain exposed to atmospheric action and, in
large part, decay. The very presence of the stump itself is taken

240

i9>'-7 STEVEXSOX— FORAIATIOX OF COAL BEDS. 643

to be evidence that it was transported, because one cannot believe
that it would resist decay long enough to permit accumulation about
it ; yet the condition is familiar, for even the slender canes of the
^Mississippi delta, killed by salt water invasion, remain standing after
they have been surrounded by several feet of silt. The filling of
stumps by sand or clay is regarded as evidence that the change
occurred after complete entombment in the mass of transported
material ; yet Potonie has shown that stumps on the shores have been
found with the decayed interior replaced with sand even into the
roots.

Some authors have laid no little emphasis on the Alartigny
debacle as showing that landslides may explain those buried forests,
whose ill situ appearance cannot be denied. But aside from the fact
that landslides are wholly exceptional and for the most part of lim-
ited extent, one may not utilize them as an explanation, unless it be
supposed that, during the Carboniferous, landslides could occur amid
conditions which would make them impossible now. According to
some authors, the great coal areas were level regions ; according to
others, they were water basins, surrounded by a vast expanse of
level area, forested or swampy. Under such circumstances a land-
slide like that of Alartigny or even like that on the lower Adige
could affect only the far away border area. But, in anv event, the
evidence of a landslide would be unmistakable ; there would be no
room for conjecture. The rock of the slide would be dift'erent from
that at the same horizon a little distance away ; and there would be
ample evidence of disturbance in the underlying rocks, produced by
downrush upon the water-soaked materials : certainly evidence of
the debacle would not be wanting. But no such evidence has been
reported from any locality ; on the contrary, where detailed descrip-
tions have been given, one finds that the bedding is undisturbed and
the conformability is complete. Equally, the buried trees are not
relics of floating islands such as those of the Amazon and Congo, for
they are not associated with filled valleys, but stand in and on rock
of the type prevailing at the horizon for long distances.

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Stated Meeting, February ?, ipii.

William W. Kkkn, :M.D.. LL.D., President, in the Chair.

Prof. WiHiam P>. Scott read a paper on "The ^lanimals, Past
and Present, of the Western 1 feniispliere," which was discussed
bv Mr. Willcox and Dr. lastrow.

Stated MeetiiHj, March ?, njii.

William W. Keen, ]\I.D., L[..D., I 'resident, in the Chair.

An invitation was received fidin the Royal Frederic University
to be represented by a delegate at the Centennial of the founding of
the I'nivcrsit}-, to be celebrated at Christiania on September 5 and
6, 1911.

The decease was announced of:
Richard Lewis Ashhurst, at Atlantic City, on January 30, 191 1,

ret. 72.
Jakob Heinrich \'an 't 1 [off, at llerlin, on March 2, 1911, a?t. 59.
Prof. V. M. Jaeger, of the Cnivcrsity of Gr(")ningen, read a paper
on " Fluid Crystals and Bi-refringent Licpiids," which was discussed
by Prof. Learned, Prof. Doolittlc and Prof. Goodspeed.

Stated Mect'uKi. .Ipril 7, iqii.
\\ iLLL\.M W. Keen, M.D., LL.D., President, in the Chair.
The following invitations were received :

:9ii.J MINUTES. V

From the Verein fiir Xatnrkundc zn Casscl. to be represenlod

at the 75th anniversary of its founding, on April 23, 191 1.
From the Societe de Ronbaix. to be represented at the 30th
Congres National des Societes Frani;aises de (leographie to
be opened at Ronbaix on July 29, 191 1.
The decease was announced of :
Benjamin Chew Tilghman, at Philadelphia, on March 6, 191 1,

set. 49.
Heber S. Thompson, at I'ottsville. Pa., on March 9, 1911, let. 70.
Henrv Pickering IJowditch, AI.l)., at Jamaica Plain, Mass., on

March 13, 191 1, aet. 71.
Samuel Frankdin bjinnon-, at Washington, on March 28, 1911,
:et. 70.
Rear-Admiral (jeorgc W. .Melville read a pai)er on " \ Century
of Steam Navigation," which was discussed by Mr. Willcox, Prof.
Doolittle and Mr. Jayne.

^Jr. Joseph Willcox offered >ome remarks on " Ixcmains uf
Glvptodon found in hdorida." and also on " Teeth of Zeuglodou froiTB
Wilmington. N. C."

General Meeting, April 20, 21, and 22, igi i.

Thursday, April 20. ( )pening Session — 2 o'clock.

Wii.iJAM W. Kkkx, M.l).. LL.D., President, in the Chair.

The decease was announced of :
Charles A. Oliver, !M.D., at Philadelphia, on April 8, 191 1,

set. 56.
Henry Pemberton, at I'hiladelphia, on April 11, 191 1, xi. 84.
The following papers were read :
"Notes on Cannon: Fourteenth and h^ifteenth Centuries," by

Charles E. Dana, Philadelphia ; discussed by Dr. Keen.
"Rise in the Cost of Fiving in the Twelfth Century and its

Fffects," by Dana C. Munro. Professor of European History,

L'niversity of Wisconsin.
" Elizabethan Physicians,"" by Felix E. Schelling, Professor of

English Literature, Cniversitv uf Penns\lvania.

vi MINUTES. [April 21,

" Moreau de St. Mery : One of Our Forgotten Members," by
J. G. Rosengarten, Philadelphia ; discussed by Prof. Cleve-
land Abbe and Mr. Sachse.

" The Relations of the United States to International Arbitra-
tion," by Hon. Charlemagne Tower, Philadelphia.

" The Early German Immigrant and the Immigration Question
of To-day," by ^\. D. Learned, Professor of German, Uni-
versity of Pennsylvania ; discussed by Prof. Henry F. Os-
born.

" On the Solution of Linear Dififerential Equations by Succes-
sive Approximations," by Preston A. Lambert, Professor of
Mathematics, Lehigh University, Bethlehem.

" Generalizations of the Problem of Several Bodies, its Inver-
sion, and an Introductory Account of Recent Progress in its
Solution," by Edgar Odell Lovett, President of the Rice In-
stitute, Houston, Texas.

" On the Totality of the Substitutions on ;; Letters which are
Commutative with Every Substitution of a Given Group on
the Same Letters," by Geo. A. Miller, Professor of Mathe-
matics, University of Illinois. (Introduced by Prof. C. L.
Doolittle.)

" Report on the Second Conference of the International Cata-
logue of Scientific Literature," by Leonard C. Gunnell, of
the Smithsonian Institution (introduced by Dr. Cyrus Ad-
ler) ; discussed by Prof. Henry F. Osborn.

Friday, A[)ril 21. Executive Session — 10 o'clock.

William W. Keex, M.D., LL.D., President, in the Chair.
Mr. Charles Francis Brush, a recently elected member, signed
the Laws and was admitted into the Society.

The Proceedings of the Officers and Council were submitted.

jMorning Session — 10.05 o'clock.
Edward C. Pickerixc, LL.D., F.R.S., \ice-President, in the Chair.
The following papers were read:

^pii-J MINUTES. vu

" Study of the Tertiary Floras of Atlantic and Gulf Coastal
Plain," by Edward \V. Berry, Associate in Pal3eontolog\%
Johns Hopkins University (introduced by Dr. J. W. Harsh-
berger) ; discussed by Prof. Harshberger and Sir John
Murray.

" The Desert Group Xolines,"" by William Trelease, Director
of the Missouri Botanical Garden, St. Louis.

" The Blueberry and Its Relation to Acid Soils," by Frederick
y. Coville, Botanist U. S. Department of Agriculture (in-
troduced by Dr. J. \\'. Harshberger ) ; discussed by Dr.
Harshberger and Dr. W. P. Wilson.

" The New Cosmogony."

"The Extension of the Solar System l)c\-on(l Xc]:)tune and the
Connection Existing Between Planets and Comets."

'' The Secular Effects of the Increase of the Sun's ]\Iass upon
the Mean Motions, ]\Iajor Axes and Eccentricities of the
Orbits of the Planets," by T. J. J. See. I'. S. Xaval Observa-
tory, Mare Island, Cal.

"Extension of Our Knowledge of the Atmosphere." by A.
Lawrence Rotch. Professor of Meteorology, Harvard Uni-
versity (introduced by Prof. \\\ M. Davis) ; discussed by
Prof. W. M. Davis.

" 1/5 Parabolic Orbits and other Results deduced from over
6200 Meteors," by C. P. Olivier, of Charlottesville, Va. (In-
troduced by Prof. Cleveland Abbe.)

" The Solar Constants of Radiation," by Charles G. Abbot,
Director of the Astrophvsical Observatory, Smithsonian In-
stitution, W^ashington. ( Introduced by Dr. Charles D. Wal-
cott. )

" Some Curiosities in the Motions of Asteroids," by Ernest W.
Brown, Professor of Mathematics, Yale University.

" Spectroscopic Proof of the Repulsion by the Sun of Gaseous
Alolecules in the Tail of Halley's Comet," by Percival Lowell,
Director of Lowell Observatory. Flagstaff, Ariz.

" Self-Luminous Xight Haze," by Edward E. Barnard, Astron-
omer, Yerkes Observatorv, \\'illiaius Bav, Wis.

via MINUTES. [April 21.

"Some Peculiarities in the Motions of the Stars," by W. W.
CampbeU, Director of Lick Observatory, Mt. Hamilton, Cal. ;
discussed l)y Dr. See, Prof. Pickering and Dr. C. G. Abbot.

Afternoon Session — 2 o'clock.

William W. Keen, M.D., LL.D., President, in the Chair.

" Shore and Off-Shore Deposits of Silurian Age in Pennsyl-
vania," by (iilbert \'an Ingen Assistant Professor of Geol-
ogy, Princeton P'niversity (introduced by Prof. W. B. Scott) ;
discussed by Prof. W. M. Davis.

" Tertiary Formations of Xorthwestern Wyoming," by William
J. Sinclair, Instructor in Geology, Princeton L'niversity. (In-
troduced by Prof. William B. Scott. )

" On a New Phytosaur from the Triassic of Pennsylvania," by
William 15. Scott, Professor of Geology and Palaeontology,
Princeton P^niversity.

"Alimentation of Existing Continental Glaciers," by William
H. Hobbs, Professor of Geology, University of ^Michigan,
Ann Arbor.

"On the Formation of Coal Beds," by J. J. Stevenson, Emeritus
Professor of Geology, l^niversity of the City of New York.

" Problems in Petrology," by Joseph P. Iddings, U. S. Geo-
logical Survey, Washington. (Introduced by Dr. Keen.)

"Front Range of the Rocky Mountains in Colorado," by Wil-
liam Morris Davis, Professor of Geology, Harvard Univer-
sity, Cambridge.

" Sujiposed Recent Subsidence of the Atlantic Coast," by
])ouglas W. Johnson, Assistant Professor of Physiography,
Harvard I'niversity ( intrtxluced by Prof. Wm. Morris
Davis); discussed by Dr. See, Mr. \\'illcox and Prof. H.
F. Reid.

"Relation of Isostasy to the Elevation of Mountains," by
Harrv h'iclding Reid. I^rofessor of Geological Physics, Johns
Hopkins University; discussed by Prof. Iddings, Prof. W. M.
Davis, Dr. See and Prof. Reid.

"The Transi)iralion of Air Througli a Partition of Water."

Jpii.] MINUTES. ix

" Elliptic Interference with Reflecting Gratings," by Carl Barus,
Professor of Physics, Brown University, Providence.

" A Phenomenon of Vision."

" On Disruptive Discharges of Electricity through a F"lanie." by
Francis E. Xipher, Professor of Physics, Washington Uni-
versity, St. Louis ; discussed by Prof. J. McKeen Cattell.

" The High Voltage Corona in Air," by John B. Whitehead,
Professor of Applied Electricity, Johns Hopkins University.
(Introduced by Prof. Joseph S. Ames.)

" Nature and Causes of Embryonic Differentiation." by Edwin
G. Conklin, Professor of Zoology, Princeton University.

"The Origin and Significance of the Primitive Nervous Sys-
tem," by George H. Parker, Professor of Zoology, Harvard
University. (Introduced by Dr. H. H. Donaldson. I

Evening Session.

Prof. Svante Auguste Arrhenius, of Stockholm, gave an illus-
trated lecture on

" The Physical Conditions of the Planet ]\Iars."

Saturday April 22. Executive Session — 9.30 o'clock.

William W. Kkkx. M.D.. LL.D., President, in the Chair.
Pending nominations for membership were read and the polls
were opened. Secretaries Holland and Brown, tellers, subsequently
reported that the following nominees had been elected to mem-
bership :

Residents of the United States.

George A. Barton, AM., Ph.D.. Bryn ^lawr. Pa.
Bertram Borden Boltwood, Ph.D., New Haven, Conn.
Lewis Boss, A.AL, LL.D., Albany, N. Y.
John Mason Clarke, Ph.D., LL.D., Albany, N. Y.
W. M. Late Coplin, M.D., Philadelphia.
John Dewey, Ph.D., LL.D., New York City.
Leland Ossian Howard, Ph.D., Washington, D. C.
Joseph P. Iddings. Sc.D. (Yale, 1907), Chicago.

X ^IIXUTES. [April 22

Alba 1). Johnson, Rosemont, I'a.
Artlmr Amos Noyes, Ph.D.. Sc.D., LL.D.. Boston.
George Howard Parker, S.L).. Cambridge. Mass.
A. Lawrence Rotcli, S.B., A.M. (Hon. Harvard), P)Oston.
Leo S. Rowe, Ph.D., LL.D., Philadelphia.

William T. Sedgwick, Ph.D., Hon. Sc.D. (Yale, 1909), Brook-
line, ^Mass.
Angustus Trowbridge, Ph.D. (Berlin '). Princeton, X. J.
Foreign Residents.

.Svante Auguste Arrhenius, Stockholm.
Jean Baptiste Edouarde Bornet, Paris.
Sir John [Murray, K.C.B., F.R.S., LL.D., Sc.D., Edinburgh.

[Morning Session — 10 o'clock.
\\'iLi.i.\.M W. Kkex, [M.D., LL.D., President, in the Chair.

'■ Taking a Census of the Chemical Industries," by Charles E.
Munroe, Professor of Chemistry, (ieorge Washington L'ni-
versity, Washington.

"Some Recent Results in Connection with the Power of .Solu-
tions to Absorb Light," by Harry C. Jones, Professor of
Physical Chemistry, Johns Llopkins University.

'' The Properties of Salt S(jlutions in Relation to the Ionic
Theory," by Arthur A. Noyes, Professor of Theoretical
Chemistry, Massachusetts Institute of Technology ( intro-
duced by Dr. James W. Holland) ; discussed by Prof. .Arr-
henius.

" The Atomic Weight of A'anadium," Ijy ( iu>tavus Ilinrichs, of
St. Louis. (Introduced by Prof. Amos P. Brown.)

'■ Ouinazolone Azo Dyestuffs : A new Group of Azo Dyes,'^
by Marston Taylor Bogert, Head of School of Chemistry,
Columbia Cniversity, New York.

" The Secretion of the Adrenal Glands During Emotional Ex-
citement." by Walter B. Cannon, Professor of Physiology,
Harvard L^niversity ; discussed by Dr. Keen and Prof. Cattell.

" Plnlogenetic Association in Relation to the Emotions," by

191 1.] MINUTES. xi

George Crile, Professor of Clinical Surgery. Western Re-
serve University, Cleveland; discussed by Dr. Keen.

" On Coagulation of the Blood," by William H. Howell, Pro-
fessor of Physiology, Johns Hopkins University ; discussed
by Dr. Keen and Prof. Pickering.

"Abnormal Forms of Life and Their Application," by Alexis
Carrel, Associate Member of the Rockefeller Institute for
Medical Research, New York ; discussed by Dr. Leo Loeb,
Prof. Minot and Dr. Keen.

" The Cyclic Changes in the Mammalian Ovary," by Leo Loeb,
Director of the Pathological Department, St. Louis Skin and
Cancer Hospital.

" The Origin of the Porpoises of the Family DelphinidcC," bv
F. W. True, Head Curator, Department of Biology, U. S.
National ^Museum, Washington, D. C.

"Helios and Saturn," by Morris Jastrow, Jr., Professor of
Semitic Languages, Luiiversity of Pennsylvania.

" On the Religion of the Sikhs," by Maurice Bloomfield, Pro-
fessor of Sanskrit and Comparative Philology, Johns Hop-
kins University.

"An Ancient Protest Against the Curse on Eve," bv Paul
Haupt, Professor of Shemitic Languages, Johns Hopkins
University.

"Theories of Totemism," by E. Washburn Hopkins, Professor
of Sanskrit, Yale L^niversity.

" The New History," by James H. Robinson, Professor of His-
tory, Columbia University, New York (introduced by Prof.
Cheyney) ; discussed by Prof. Bloomfield and Haupt.

"Eggettes: a Conservation of Fuel," by Robert P. Field, of
Philadelphia ; discussed by Prof. Houston and Dr. See.

Afternoon Session — 2 o'clock.

William W. Keex, ALD., LL.D.. President, in the Chair.

Prof. Leslie A\\ Miller, on behalf of the subscribers presented
a portrait of Thomas Hopkinson, first President of the American
Phi]os()phical Societv.

Xli MIXUTES. [May 2

Svmposium on ^fodern \'ie\vs of Matter and Electricity.

" The Fnndaniental Principles," by Daniel F. Comstock, As-
sistant Professor of Theoretical Physics, Massachusetts In-
stitute of Technology. ( Introduced by Prof. W. F. Magie.)
" Radioactivity," by Bertram B. Pjoltwood, Professor of Radio-
Chemistry, Yale University.
" Dynamical Efifects of Aggregates of Electrons," by Owen \V.

Richardson, Professor of Physics, Princeton University.
"The Constitution of the Atom," by H. A. Wilson, F.R.S.,
Professor of Physics, McGill University, ^Montreal (intro-
duced by Prof. ]\Iagie ) ; discussed by Profs. Magie, Web-
ster, Heyl, Arrhenius, I'ickering and C. L. Doolittle.
Prof. Bertram B. Boltwood.
Prof. Arthur Amos Noyes.
Prof. George Howard I'arker.
Mr. A. Lawrence Rotch.
Prof. Svante A. Arrhenius.
Sir John Murray, K.C.B.

Xewlv-elected members signed the Laws and were admitted into
the Society.

An obituary notice of Prof, jakoli II. van't HoiT was read by
Harry C. Jones, Professor of Physical Chemistry, Johns Hopkins
Universitv.

Special McctiiKj. .]jay J. ivii.
W'lLi.JA.M W. Keex, M.D.. LL.D., Pre>ident. in the Chair.

Prof. Cieorge A. Barton.

Dr. \\'. .M. Late Coplin.

Mr. Alba 11. Johnson.

Prof. Leo S. Rowe.
newl}-elected members signed the laws and were admitted into the
-ocietv.

I9II.] MIXUTES. adii

Stated Meeting, May j, igii.
\\'iLLiAM W. Keex, M.D., LL.D., President, in the Chair.

Letters accepting membership were read from :

George A. Barton. A.M., Ph.D., Bryn ^lawr, Pa.

Bertram Borden Bohwood, Ph.D., Xew Haven, Conn.

John ^lason Clarke, Ph.D., LL.D., Albany, X. Y.

A\'. M. Late Coplin, ^LD.. Philadelphia.

John Dewey, Ph.D., LL.D.. Xew York City.

Leland Ossian Howard. Ph.D.. Washington, D. C.

Joseph P. Iddings, Sc.D. (Yale. 1907), Chicago.

Alba B. Johnson, Rosemont, Pa.

Arthur Amos Xoyes, Ph.D., Sc.D., LL.D., Boston.

George Howard Parker, S.D., Cambridge, Mass.

A. Lawrence Rotch, S.B.. A.AL (Hon. Harvard), Boston.

Leo S. Rowe, Ph.D.. LL.D., Philadelphia.

William T. Sedgwick, Ph.D., Hon. Sc.D. (Yale. 1909), Brook-
line. Mass.

Augustus Trowbridge. Ph.D. (Berlin), Princeton, X. J.

Svante Auguste Arrhenius, Stockholm.

Sir John ^^lurray, K.C.B., F.R.S., LL.D., Sc.D., Edinburgh.

The following papers were read :
Obituary notice of Prof. George F. Barker, by Prof. Elihu

Thomson, of Swampscott, Mass.
" The Lignite Coals of the L'nited States and their Utilization,"
by Joseph A. Holmes. Director of the Bureau of Mines,
Washington.
" William Rush — the First American Sculptor," by Edward H.
Coates, Esq. (Introduced by Dr. W. AA'. Keen. )

Stated Meeting. Oetober 6. igii.
Charles L. Doolittle, Sc.D., in the Chair.

Letters accepting membership were read from :

Edouarde Bornet, Paris.

Lewis Boss, Albany.
The decease of the following members was announced :

xiv MINUTES. [Oct. 6,

Edouard du Pont, at Cannes, France, on ]\Iarch 31, 191 1, aet. 70.
Samuel Hubbard Scudder, at Cambridge, Mass., on May 17,

191 1, set. 74.
G. Johnstone Stoney, at London, Eng., on July i, 191 1, set. 85.
James Christie, at Atlantic City, on August 24, 191 1, set. 71.
James Andrew March, at Easton. Pa., on September 9, 191 1,

jet. 86.
Francis Jordan, Jr., at Point Pleasant, X. J., on September 12,
i 191 1, set. 68.
Pierre Emile Levasseur, at Paris, ret. 82.

Stated Meeting. Xovember 5, /p//.

William W. Keen, M.D., LL.D., President, in the Chair.
The decease of the following members was announced:
A. B. Meyer, at Berlin, £et. 71.

Henry C. McCook, at Devon, Pa., on October 31, 1911, set. 74.
The following papers were read :
" Factors Affecting Changes in Body-Weight," by Francis G.

Benedict.
" Formation of Coal Beds — Some Elementary Problems," by
John J. Stevenson.

Stated Meeting. December i. iQii.

William W. Keex, M.D., LL.D., President, in the Chair.
The decease was announced of :
George F. Dunning, at York Cliffs, ]\Ie., on June 26, 1910,
set. 93.
Mr. Arthur L. Day read a paper on " Geophysical Research."

CORRIGEXDUM

In Mr. Berry's article on " A Study of the Tertiary
Floras of the Atlantic and Gulf Coastal Plain" in No. 199,
the sketch maps on pages 306 and 308, by mistake, have
been transposed and that on page 308 should have been
printed on page 306 and that on page 306 should have been
printed on page 308. The legends are correctly numbered,
but Fig. I has been printed over the legend of Fig. 2 and
vice 7'crsa.

INDEX

Abbot, solar constant of radiation,
235, I'ii

Adrenal glands, secretion of. during
emotional excitement. 226, .r

Air, high voltage corona in. 374, ;.r

. transpiration of, through a

partition of water, 117, viii

Alligator snapper and fossil, 455

Arbitration, relations of U. S. to in-
ternational, z'i

Arrhenius. physical conditions of
;\Iars. ix

Asteroids, some curiosities in mo-
tions of. vii

Atlantic Coast, supposed recent sub-
sidence of, via

Atmosphere, extension of our knowl-
edge of, z'ii

Atom, constitution of. 366

B

Barker, George Frederick, obituary

notice of. xiii
Barnard, self-luminous night haze.

246, zii
Barus, elliptic interference with re-
flecting gratings, 125, ix
. transpiration of air through a

partition of water, 117
Benedict, factors affecting changes in

body-weight, xiv
Berry, tertiary floras of Atlantic and

Gulf coastal plain. 301, zii
Blood, coagulation of, xi
Bloomfield, religion of Sikhs, xi
Blueberry, and its relation to acid

soils, z'ii
Bogert, quinazolone arzo dye stuff's,

X

Boltwood. radioactivity, ;^2^. xii
Brown, some curiosities in the mo-
tions of asteroids, z'ii
Bryce, obituary notice of Henry
Charles Lea, xxiv

Campbell, some peculiarities in mo-
tions of stars, via
Cannon, notes on, 147, v

Cannon, stimulation of adrenal secre-
tion by emotional excitement, 226. x

Carrel, abnormal forms of life, and
their application, xi

Chemical industries, census of, x

Cheyney, obituarj- notice of Henrj'
Charles Lea, iii

Coal beds, formation of, i. 519, viii.
xiz'

Coates. William Rush, the first
American sculptor, xiii

Comet. Halley's, repulsion of gaseous
molecules in tail of. 254

Comstock, modern theory of elec-
tricity and matter. 321

Conklin. nature and causes of em-
bryonic differentiation. ;.r

Corona, high voltage, in air. 374

Cosmogony, the new. 261. z'ii

Cost of living in twelftli century, rise
in. V

Coville, blueberry and its relation to
acid soils, z'ii

Crile, phylogenetic association in re-
lation to the emotions, x

Cr_vstals. fluid, and bi-refringent
liquids, iz'

D

Dana, notes on cannon, fourteenth

and fifteenth centuries. 147. f
Davis, front range of Rocky [Moun-
tains in Colorado, z'iii
Day, Geophysical research, xiv
Differentiation, embryonic, ix
Dyestuffs, Quinazolene Azo, .r

E

Eggettes : a conservation of fuel, xi
Electricity, disruptive discharges of,

through flames, 397, ix
, and matter, modern theory of.

Electrons, aggregates of. 347

Elliptic interference with reflecting
gratings, 125, ix

Equations, solution of linear differ-
ential, by successive approximation.
274. ■:•/

Eve. an ancient protest against the
curse of, 505, xi

INDEX.

Explosives, investigation of, at Pitts-
burgh Testing Station, Hi

Field, Eggettes : a conservation of

fuel, xi
Floras, tertiarj-, of Atlantic and Gulf

coastal plains, 301, 7'ii
Furness, obituary notice of Henry

Charles Lea, xxix

Geophysical Research, xiv

Glaciers, alimentation of existing
continental, z'lii

Glyptodon, remains of, found in
Florida, v

Gunnell, second Conference of the
International Catalogue of Scien-
tific Literature, vi

H

Harshberger. influence of sea water
on distribution of plants, 457

Haupt, Paul, an ancient protest
against the curse of Eve, 505, xi

Hay, a fossil specimen of the alli-
gator snapper ( Alacrochelys tem-
minckii ) from Texas, 452

Haze, self-luminous night, 246, vH

Helios and Saturn, xi

Hinrichs, the atomic weight of vana-
dium, 191, X

History, the new, 179. xi

Hobbs, alimentation of existing con-
tinental glaciers, I'lii

Holmes, lignite coals of the LT. S.
and their utilization, xiii

Hopkins, theories of totemism. xi

Hopkinson, Thomas, presentation of
portrait of, xi

Howell, coagulation of the lilnod, xi

Iddings, problems in petrology, 286,
viii

Immigrant, the early German, and
the immigration question of to-day.
vi

International arbitration, relations of
U. S. to, 7.7:

Ionic theory, properties of salt solu-
tions in relation to. x

Isostasy and mountain ranges, 444,

Jaeger, fluid crystals and bi-re-
fringcnt liciuids, i-j

Jastrow, Helios and Saturn, xi
Johnson, supposed recent subsidence

of the Atlantic Coast, viii
Jones, power of solution to absorb

light, X
obituary notice of Jacobus

Henricus Van't Hoff, iii, xii

Lambert, solution of linear differ-
ential equations by successive ap-
proximations, 274, vi

Lea. Henry Charles, obituary notice
of. iii

, portrait of, presented, xxxvii

, Isaac, portrait of, presented,

xxxix

Learned, the early German immi-
grant, and immigration question of
to-day, z'i

Life, abnormal forms of, xi

Light, power of solutions to absorb,

X

Lignite coals of U. S. and their

utilization, xiii
Liquids, bi-refringent, iz'
Living, cost of, in 12th Century, 497,

Loeb, cyclic changes in mammalian
ovary, 228, xi

Lovett, generalizations of problem of
several bodies, z'i

Lowell, repulsion of gaseous mole-
cules in tail of Halley's comet, 254,
vii

M

Mammals, past and present of west-
ern hemisphere, iz'
Mars, physical conditions of, ix
Matter and electricity, symposium

on modern views of, xii
Meeting, general, v

, special, xii

. stated, iii. iv, v, vi, vii, viii, ix,

X. xi. xii. xiii
Melville, a century of steam naviga-
tion, v
Members deceased :

Ashhurst. Richard Lewis, iv

Bertin, Georges, iii

Bowditch, Henry R., v

Christie, James, xiv

Cook, Joel, Hi

Dunning, George F., xiv

du Pont, Edouard, xiv

Emmons, S. F., z'

Jordan, Francis, Jr., xiv

Levasseur, Pierre Emile, xiv

IXDEX.

jMembers deceased (continued)
!McCook. Henry C, xiv
March, James Andrew, xiv
!\Ieyer, A. B., xiv
Oliver, Charles A., v
Pemberton, Henry, v
Scudder, Samuel Hubbard, xiv
Stoney, G. Johnstone, xiv
Thompson, Heber S., v
Tilghman, Benjamin Chew, v
Van't Hoff, Jakob Heinrich, iv
Whitman, Charles Otis, Hi
Members elected, ix, x

, presented, z'l, xii

Membership accepted, xiii

Miller, totality of substitutions on ;;

letters, 139, zi
^Molecules, gaseous, in tail of Halley's

comet, repulsion of, z'ii
]\Ioreau de Saint Mery and his
French friends in the A. P. S.. 168,
z-i
Mountain ranges, isostasy and. 444
!Munro, rise in cost of living in

twelfth century, 497. v
iMunroe. census of chemical in-
dustries, X

, investigation of explosives at

Pittsburgh Testing Station, Hi

N

11 letters, totality of substitutions on,

139. c't
Navigation, steam, a century of, v
Nervous system, origin and signifi-
cance of primitive, 217, ix
Nipher, disruptive discharges of elec-
tricity through flames, 397, ix

, an optical phenomenon, 316, ix

Nolineae, desert group, 405, zii
Noyes, properties of salt solutions in
relation to ionic theory, x

0

Obituarj- notice of George Frederick

Barker, xiii

Henry Charles Lea, iii

Jacobus Henricus Van't

Hoff, iii, xii
Officers and Council, election of. Hi,

iz'
Olivier, 175 parabolic orbits and other

results deduced from over 6,200

meteors, rii
Orbits, 175 parabolic, deduced from

over 6.200 meteors, z'it
Ovary, cyclic changes in mammalian.

228, xi

Parker, origin and significance of

primitive nervous system, 217, ix
Petrology, problems in. 286, z'iii
Phylogenetic association in relation

to the emotions, x
Physicians, Elizabethan, v
Phytosaur from the Triassic of

Pennsylvania, z'iii
Porpoises of the family Delphinidse,

xi
Portrait of Thomas Hopkinson, xi

Henr}- C. Lea, xxxvii

Isaac Lea. xxxix

R

Radiation, solar constants of, vii

Radioactivity, 333

Reid, relation of isostasy to elevation
of mountains, 444, z'iii

, the transpiration of air through

a partition of water, z'iii

Religion of Sikhs, xi

Richardson, dynamical effects of ag-
gregates of electrons, 347, xii

Robinson, the new history, 179, xi

Rocky Mountains in Colorado, front
range of the. z'Hi

Rosengarten, IMoreau de Saint Alery,
and his French friends in the A.
P. S., 168. vi

Rotch, extension of our knowledge
of the atmosphere, zii

Royal Frederick University Centen-
nial, invitation to, iv

Rush. William, the first American
sculptor, xiii

Schelling, Elizabethan physicians, z^

Scott, mammals, past and present of
the Western hemisphere, iv

, a new phytosaur from triassac

of Pennsylvania, viii

Sea water, influence of, on distribu-
tion of plants, 457

See. extension of solar system beyond
Neptune. 266, vii

, the new cosmogony, 261, z'ii

. secular effects of increase of

sun's mass. 269, z'ii

Several bodies, generalizations of
problem of, vi

Shore and off-shore deposits of
Silurian age in Penna., ziii

Silurian age in Pennsylvania, shore
and off-shore deposits of, viii

Sinclair, tertiary formations of north-
western Wyoming, znii

INDEX.

Societe de Roubaix, invitation to 30th

Congres National des Societe de

Geographie, v
Solar-constant of radiation, 235
system, extension of, beyond

Neptune, 266. vii
Stars, some peculiarities in motions

of, I'iii
Stevenson, formation of coal beds, i,

519, z'iii, .1 iv
Sun's mass, secular effects of increase

of, 269, vii
Symposium on modern theory of

electricity and matter, 321, :^2^, 347,

366, xii

T
Teeth of Zeuglodon, v
Tertiary formations of northwestern

Wyoming. I'i'i
Thomson, obituary notice of George

Frederick Barker, xiii
Totemism, theories of, xi
Tower, the relations of U. S. to in-
ternational arbitration, vi
Trelease, desert group Xolinese, 405,

vii

True, origin of porpoises of family
Delphinidc'e, .r;

Vanadium, atomic weight of, 191, x

Van Ingen, shore and ofif-shore de-
posits, Silurian age in Pa., viii

Van't Hoff, Jacobus Henricus,
obituary notice of. Hi, xii

Verein fiir Naturkunde zu Cassel,
invitation to its 75th anniversary,

Vision, a phenomenon of, 316, ix

W

Whitehead, the high voltage corona
in air, 374, ix

Willcox, remains of glyptodon found
in Florida, z'

. teeth of Zeuglodon from Wil-
mington,, N. C. V

Wilson, constitution of the atom, 366.
xii

Z

Zeuglodon, teeth of, v

Proceedings Am. Philos. Soc. Vol. L No. 200

Plate I

NOLINA MICROCARPA

-*#•

Sif^'-

?.''^..''

•^'r

-r^

■-\C:.

'-^^>

^V.

.. 'J-.

i

■M'

i-4\

4 - ^

%■ ■*-'"•<: ^

„^,,^' . '

-*' -

- •■ «c=--^- ■ ..^

i^|^*f^

Proceedings Am. Philos. Soc. Vol. L. No. 200

Plate III

NOLINA LONGIFOLIA

Proceedings Am. Philos. Soc. Vol. L. No. 200

Plate IV

' t'

*//;...

Beaucarnea gracilis

Proceedings Am. Philos. Soc. Vol. L. No. 200

Plate V

A. — Nolina

B. — Nolina

%

,^

C. — Dasylirion
Inflorescence of Nolineae

Proceedings Am. Ph;los. Soc. Vol. L. No. 200

Plate VI

A. — Xolina

B. — Calibanus
Inflorescence of Nolineae

Proceedings Am. Philos. Soc. Vol. L. No. 200

Plate VII

^5S&v

A — Beaucarnea

B. — Dasylirioii
Inflorescence of Nolineae

Proceedings Am. Philos. Soc. Vol. L. No. 200

Plate VIII

Flowers of Nolineae

Proceedings Am. Philos. Soc. Vol. L. No. 200

Plate IX

A. — Dai\liriou

B. — Calibanu?
Nectary of Nolineae

Proceedings Am. Philos. Soc. Vol. L. No. 200

Plate X

Seeds of Nolineae

Proceedings Am. Philos. Soc. Vol. L. No. 200

Plate XI

• • i

» • (9

A — Normal

B. — Teratological
Fruits of Nolineae

Proceedings Am. Philos. Soc. Vol. L. No. 200

Plate XII

A. — Wilina

<ftf t#il|f#

t: V^vl^ ^'f

4 V

1

Iv%, If

ft ?-^

B. — Da?\'liri()n

Fruits of Nolineae

PROCEEDINGS AM. Philos. Soc. Vol. L. No. 200

Plate XIII

Germination of Nolina longifolia

Proceedings Am. Philos. Soc. Vol. L. No. 200

Plate XIV

A. — Beaucarnea

B. — Calibanus
Germination of Nolineae

Proceedings Am. Philos. Soc. Vol. L. No. 200

Plate XV

Haustorium and Leaf Tips of Dasylirion

Proceedings Am. Philos. Sec. Vol.. L. No. 200

Plate XVI

NOLINA HARTWEGIANA

Proceedings Am. Philos. Soc. Vol. L. No. 200

Plate XVII

NOLINA RIGIDA

Proceedings Am. Philos. Soc. Vol. L No. 200

Plate XVIIl

IVFacrochelys TEMMINCKII X

Proceedings Am. Philos. Soc. Vol. L. No. 200

■s.mo/r.^

Plate XIX

per -6

rnar-S

per- 7

ma/)-. 9

Macrochelys TEMMINCKII. X

Proceedings Am. Philos. Soc. Vol. L. No. 201

Plate XX

Fig. a

Fig. B
Salt Marshes near Avaloii, N. J.

Proceedings Am. Philos. Soc. Vol L. No. 201

Plate XXI

^p.^^

GENERAL INDEX

TO THE

PROCEEDINGS

OF THE

American Philosophical Society

HELD AT PHILADELPHIA

FOR

PROMOTING USEFUL KNOWLEDGE

VOLUMES 1-50
1838-191 I

PHILADELPHIA
THE AMERICAN PHILOSOPHICAL SOCIETY

1912

GENERAL INDEX

TO THE

PROCEEDINGS

OF THE

American Philosophical Society

HELD AT PHILADELPHIA

FOR

PROMOTING USEFUL KNOWLEDGE

VOLUMES i-^o
1 838- 1 9 1 1

PHILADELPHL\
THE AMERICAN PHILOSOPHICAL SOCIETY

1912

Press of
ERA Printing Com
Lancaster, pa

NOTE.

This General Index includes the papers printed in the following
publications of the Society :

Proceedings. \'o1. I (1838) to L (1911). 8vo.
Current.

• Memorial J'olitnie I (1896-1900).

Svo.

Trans.^ctions of the Historical and Literary
Committee. Vol. I (1819) to III, part i (1843).
Svo.

The references to the vohane number are distinguished by heavy-
faced type, and to the page number by lighter faced type.

GENERAL INDEX

TO THE

PROCEEDINGS

OF THE

AMERICAN PHILOSOPHICAL SOCIETY
A^oL. I (1838) TO Vol. L (1911) .

Abbe, Cleveland, aurora, altitude of,
above the earth's surface, 37, 4.

Benjamin Franklin as meteoro-
logist, 45, 117.

Abbeville quarries, 9, 388.

Abbott, A. C. & Bergey, D. H., influ-
ence of alcoholic intoxication upon
certain factors in the phenomena
of haemolysis and bacteriolysis, 41,
140.

Abbott, Charles Conrad, occurrence
of artifacts beneath a deposit of
clay, 43, 161.

explanation of reported showers

of toads, 43, 163.

Abbot, C. G., solar constant of radia-
tion, 50, 235.

Abbott, Helen C. de S., new crys-
talline compounds, in higher plants,
25, 124.

Accessory nerve in cat, 25, 94.

Acetobenzoic anhydride, action of hy-
drochloric acid and chlorine on, 19,

13-
Ackerman, meteorological register at

Bois-chene, 11, 499.
Acoustic phenomenon in Rocky

Mountains, 13, 499.
Adams, E. P., propagation of long

electric waves along wires, 49, 364.

ABBE-AIR
xA.docidje, 11, 547; 17, 82.
Adocus, II, 295.
Adrenal secretion, stimulation of^

by emotional excitement, 50, 226.
Aerolites, relation of, to shooting

stars, 24, III.
Aerolitic epoch of November, 17, 339,

stars, 24, III.
Aethereal density and polarity, 12,

407.
— influences in solar system, 16, 496.
— oscillation, the primordial material

force, 12, 411.
African dialects, 9, 3.
— exploration, 10, 95.
After-color, subjective, 23, 500.
Agassiz, L., Naiades, 5, 187, 219.
Agave, species in, 49, 231.
Aggregation and dissociation, centers

of, 16, 496.
Agnew, D. Hayes, obituary notice

of, 22, 227.
Agriculture, importance of phosphoric

acid in, 8, 378.
— the new, 45, 166.
Agriochoerus, notes on the osteology

of. 33, 243.
Air, exploration of upper, by means

of kites and balloons, 48, 8.
— -rarefaction of, i, 237.

AIR-AMERICAN

GEXERAL IXDEX

Air (continued).

— transpiration of, through a parti-
tion of water, 50, 117.

Alaguilac language of Guatemala, 24,

366.
Alaman, Don Lucas, obituary notice

of, 5, ?,?,(i-
Alaska boundary, progress of the

demarcation of, 47, 86.

— ichthyology of, 13, 24.
Alaskaite from the series bisiuuth

sulphosalts, 19, 472.

— note on, 22, 211.
Albirupean formation, and its near-
est relatives in Maryland, 25, 42.

Alcohol, synthetic, 46, 117.

Alexander. John H., decay of arti-
cles deposited in corner stones. 5,
350.

Alexander. Joseph Addison, obitu-
ary notice of, 7, 320.

Alexander. Stephen, aurora of Sep.
3. 1839, I, 132.

-change in Biela's comet, 4, 241.

contributions to astronomical

science, 4, 216.

• meteors, 2, 45.

— • — solar eclipses, 2, 201; 3, 183:
5, 32.

Algse, fresh water, of eastern
North America, 11, 119.

Algebraic functions, expansion of.
at singular points, 43, 164.

Alger, Abby L., words and phrases
taken from the Passamaquoddy
tongue. 21, 240.

Alkaline carbonates, decomposition
of, 3, III.

Allegheny mountains, section across,
II, 115.

— river, ancient buried channel
crossing, 18, 354.

Allen, G., physical geography of
United States, 16, 61.

Allen, Harrison, Atalapha. new spe-
cies of. 29, 5.

Allen. Harrison (continued).

C'lrollia. new species of, 28,

19.
— ■ — human congenital malformation,

21, 413-
Macrotus, new species of, 28,

/-•
Xyctinomus. on the Genus, and

two new species of, 26, 558.

— — ^ obituary notice of Albert H.
Smith, 23, 606.

-osteology, 11, 117.

Pronghorn (Antilocapra Amer-
icana), 26, 366.
Pteropus, new species of, 28,

70.
teeth, variations of forms of

human. 28, 30.
Allen, T., gas wells on the Kanawha,

4» 366.
Almanacs, early Philadelphia, 19,

291.
Almighty, Hebrew word for, 23, 303.
Alphabet, correct name of the last

letter of the English, 21, 330.
Aluminum, 6, 141, 148, 172.
Amazonas, lower, geology of, 18, 155.
Amblypoda, mechanical origin of the

dentition of the, 25, 80.
America, two early maps of, 19, 10.
Americari history from " German

Archives." 39, 129, 683.

— languages, philosophic grammar
of. as set forth by Wilhelm von
Humboldt, 22, 306.

polysynthesis and incorpora-
tion in. 22, 306.

American Philosophical Society,
Centennial of, 3, i.

. — incorporation of, 18, 513.

, — occupation of Hall, 26, 4.

• — opinion as to the right to

tax its ?lall. 9, 14.

part taken bj-, in establish-
ing stations for meteorological ob-
servations, II, 516.

PROCEEDINGS. VOLS. 1-50

AMER-ARUBA

American Philosophical Societ}- (con-
tinued).

Sesqui-centennial of. 32, 5.

Ames, Charles G., obituary notice of
Ralph Waldo Emerson. 20, 498.

Amphide salts, 2, 219.

Amphiumidas, structure and affini-
ties of the. 23, 442.

Analysis, form. 45, no.

Analytical trigonometry, 3, 49.

Anamitic language, i, 235.

Anatomy, microscopic, 3, 89.

Andagucda dialect of the Choco
Stock, 34, 401.

Andaman and Nicobar Islands, brains
of natives of the. 47, 51.

Andrews. Charles 'SI., obituary notice
of Daniel Coit Gilman. 48, Ixii.

Anemometer, 2, 57.

Angell, James B., obituary notice of
Henry Simmons Frieze, 28, 59.

Anisodactylus of the United States,
19, 162.

Anode, rotating, and mercury cathode
in electro-analysis, 44, 137.

in the electrolj-tic precipitation

of uranium and molybdenum, 45,
268.

Antarctic expedition. 2, 2t,t, ; 48, vii,
49. vii.

— geology and polar climates. 49,
200.

Anthon. C. A., silver Louis of fifteen
sous, struck under Louis XIV, for
circulation in French America, 16,

293-
Anthracite coal basins, map of, 11,

113; 13, 155-

— — from Colorado, 20, 205.
waste, apparatus to consume.

16, 214.
Anticlinal in Wythe Co. lead mine,

10, 270.
Anx, notes on Hebrew etymologies

from the Egyptian. 29, 17.
Apatela, 34. 388.

Apjohn"s formula, 2, 255.

Apollonius of Tyre, 37, 206.

Arago's neutral points, 10, 223.

Aransas Pass, Tex., reaction break-
water at, 38, 135.

Arbitration. International, 36, 320.

proposed tribunal of, of 1623,

46, 302.

Archaeological expedition to Syria.
Princeton L'niversity, 46, 182.

Archaeology. American, public col-
lections of. in the United States,
21, III.

Archsesthetism, 20, 232.

Arctic Archipelago, geology of. 7,

293-

— expedition of 1866. 8, 383.

— exploration. 5, 159. 224. 357.

— Ocean, drift-casks in. 41, 154.

— plants. 5, 266; 6, 186.

— regions, characteristics of the in-
land ice of the. 49, 57.

Areography. 41, 225.

Arfvedsonite. 16, 516.

Arizona, Sulphur Spring \'alley. bor-
ings, and agricultural experiments
in. 40, i6r.

Arkansas peat and lignite. 20, 22^.

Arranda language. Central Australia,
46, 322

Arsenic acid, trisulphoxj^ 43, 112.

Art. philosophy of, 32, 56.

— and ethnology, 47, 30.

Artesian wells in Montgomery

County. 29, 43.
Arthropoda, classification of. 42, 142.
Artifacts, occurrence of, beneath a

deposit of clay. 43, 161.
Artiodactyla. classification and phylo-

geny of the, 24, 377.

— of North America, structure of the
feet m the extinct. 22, 21.

Artiodactyls of the Uinta formation,
on the Selenodont. 37, 73.

Aruba language and the Papiamento
jargon, 22, 299.

ARVAL-AURORAL

GENERAL IXDEX

Arval Brethren, Etrusco-Libyan ele-
ments in the song of the, 30, 317.
Ashburner, Charles A., Bradford oil

sand, 18, 419.
— — Bureau of ]^Iines, 20, 206.

Colorado anthracite, 20, 205.

-estimation of coal areas, 20,

232.
-geological section at St. Clary's,

Elk County, Pa., 19, T,yj.
Kintzes' firedamp indicator, 21,

283.
measured section of Pennsyl-

Paheozoic rocks, 16, 519.
Natural Bridge of Virginia. 21,

699.

obituary notice of, 28, 53.

-oil well records in AlcKean and

Elk Counties, Pa., 18, 9.
— - — Second Geological Survey of

Pennsylvania, recent publication^

of, 22, 86.
spouting water well at Wilcox,

Pa., 17, 127.
Ashes, fresh wood, influence of, on

the growth of wheat, potatoes, &c.,

12. 323-

Ashley, George H., Paleozoic area of
Arkansas south of the NovacuJite
Region. 36, 217.

Ashmead, Albert S., testimony of the
Huacos (Mummy-grave) potteries
of old Peru, 42, 378.

Asphalt, production of an. resem-
bling Gilsonite by the distillation of
a mi.xture of fish and wood. 37,
171.

— West Virginia, 9, 183.

Asphaltum in New Brunswick. 5, 241.

Assay Balances, 9, 226.

" Assembly Account," the First. Phil-
adelphia, 1748, 41, 260.

Association, the dominating need of
man arid the keynote of social sci-
ence, 33, 134.

Astaci, three extinct, from fresh
water territory of Idaho, 11, 605.

Asteracanthus, 11, 440.
Asteroids between Mars and Jupiter,
mass of, II, 498.

— mutual relations between the orbits
of certain, 30, 269.

— origin of the zone of, and the
capture of satellites, 49, 35 r.

— zone of, and the ring of Saturn,
21, 263.

Astraea, observations on. 4, 347
Astrological manuscript in cipher,

translation of, 13, 477.
Astronomical approximations. 18,

380, 425 ; 19, 4, 18, 20.

— observations, 2, 103.

at Hudson Observatory, 2, 51.

— -science, contributions to. 4, 216.

illustrations of progress made

during recent years in. 32, 97.

Astrophyllite. Arfvedsonite and Zir-
con, from El Paso Co., Colorado,

16, 509.

Atalapha, new species of, 29, 5.
Atmospheric air, law of cooling of,

3, i.SS-
— - physics and climatology, catalogue

of works on. 32, 248.
Atom, constitution of. 50, 2>^6.
Atoms, chemical, 16, 505.
Atrypa, crural processes in genus.

17, 337-

Attaci, North American. 14, 256.
Attraction, heat and. 10, 97.

— origin of force of. 14, iii.
Aurora of Sep. 3. 1839. i, 132.

— -of February 7. 20. 21. 1866. 10,
206.

— of April 15, 1869. II, III.

— of April 10, 1872, spectroscopic
examination of. 12, 579.

— of April 16-T7. 1882, 20, 283.

— attitude of, above the earth's
surface, 10, 24; 37, 4.

— at Cape Breton. 9, 60.

— and earthquake, 11, 522.
Auroral and meteoric means, daily,

12, 516.

4

PROCEEDIXGS, VOLS, i-^o

AURORAS-BALCH

Auroras, 6, 162.

— general relation of, to rainfall,
12, 400.

— influence of meteoric showers on,
12, 401.

— recent, 11, 522.

— -relation of, to gravitating cur-
rents, 12, 121.

Australia, Western, languages of
some tribes of, 46, 361.

Australian aborigines, origin, organi-
zation and ceremonies of, 39, 556.

— tribes, divisions of, 37, 151.

— — initiation ceremonies of, 37,
54-

North, divisions of, 38, 75.

Austrian mone\', specimens of, 8,

264.
Azimuths, determination of, 4, 234.

Babinet's neutral points, 10, 223.

Bache, Alexander Dallas, anemom-
eter 2, 57.

Apjohn's formula, 2, 255.

coral reefs, 2, 150.

— ■ — corrosion of cables bj- sea
water, i, 70.

■ dew point hygrometer, 2, 249,

252.

Espy's theory. 2, 147.

formulation of cumulus cloud

from the action of a fire, 2, 116.

fusible metal, 2, 42.

induction inclinometer, 2, 2^/.

■ instrument to determine con-
ducting power of bodies for heat,
3, 132.

magnetic dip, i, 146, 151; 4, 11.

. — -observations, i, 185, 294; 2,

69, 83, loi, 150; 3, 90, 175-

meteors, i, 300; 2, 235, 267.

— — new base apparatus, 4, 368.
rain guage, 2, 164.

standard weights, measures and

balances, 4, 159.

■9S *z 'siujg;s

Bache, Franklin, obituary notice of,

10, 121.
President's address, 5, 360; 6,

67.
Bache, Hartman, magnetic meridian,

2, 137-
— ■ — survey of Sandy Hook, 4, 168.
Bache, R. ^leade, boxing, dynamics

of, 33, 179-
Brownian movements, 33, 163.

— — -City water, sterilization of. 29,
26.

osmazome, conservation of, in

roasting, 31, 318.

— ^personal equation, 34, ^t,-.

■ photogrammetr}-, civil and mili-

tar}-, 30, 229.

— — University Extension teaching,
29. 50.

Bacteriolysis and haemolysis, 41, 140.

Bahamas and Jamaica, observations
on the, 29, 145.

Bailey, L. H., forward movement in
plant-breeding. 42, 54.

organic evolution from a botan-
ical standpoint. 35, 88, no, 113.

Baird, Henry Carey, association, 33,

134-

— • — -Carey and two of his recent
critics, 29, 166.

— • — obituary notice of Alexander
Biddle, Memorial Volume, i, 196.

Baird, Henry M., Benjamin Franklin,
diplomatic services of, 28, 209.

Balaenoptera Cope, 12, 108.

Balch. Edwin Swift, art and eth-
nology. 47, 30.

why America should re-explore

Wilkes Land, 48, 34.

Balch, Thomas Willing, American-
British Atlantic Fisheries question,

48. 319.

First " Assembly Account.''

Philadelphia. 1748, 41, 260.

— — law of Oresme, Copernicus and
Gresham. 47, 18.

BALCH-BATRACH

GENERAL INDEX

Balch, Tliomas Willing- (continued).

proposed International Tribunal

of Arbitration of 1623, 46, 302.

Baldwin, Matthias W., obituar}- no-
tice of, 10, 279.

Balloons, exploration of the upper
air by kites and, 48, 8.

Bancker, Charles Nicoll, obituary
notice of, 11, 85.

Bar, mythical compounds of, 10, 137.

Barbadoes, cyclical rainfall at, 14,

195-

Barite, 24, 434.

Barium, extraction of, i, 130.

Barker, George F., Draper Memorial
photographs of stellar spectra, 24,
166.

electrical progress since 1743,

32, 104.

• measurement of electromotive

force, 20, 649.

-new vertical lantern galvanom-
eter, 14, 440.

obituary notice of, 50, xiii.

, -of Henry Draper, 20,

656.

. of Frederick Augustus

Genth, 40, x.

solar eclipse of July 29. 1878,

18, 103.

Barnard, E. E., photographic obser-
vations of Daniel's comet, 49, 3.

results of astronomical photog-
raphy, 46, 417.

— — self-luminous night-haze, 50,
246.

Barometer, Becker's aneroid, 7, 342.

— diurnal variations of the, 9, 283.

— high, of February 10 and 11, 1867,
10, 329.

— improvements in the hypsomctrical,
20, 604.

Barrett. O., Jr., list of elevations
in Indiana Co., Pa., 17, 145.

Bars, dynamic action of the ocean in
building, 26, T4(').

Bartlett, William H. C, comet of
1843, 3, 152.

instruments used at West Point,

N. Y., 3, 151-

Barton, Benjamin Smith, pernicious
insects of North America, 22, 369.

Barus, Carl, adjustment for the plane
grating similar to Rowland's
method for the concave grating,
48, 166.

distribution of nuclei in dust-
free wet-air, 46, 70.

election method of standardizing

the coronas of cloudy condensation,
48, 177-

— ■ — electrometric measurement of
the voltaic potential difference be-
tween the two conductors of a con-
denser containing a highly ionized
medium, 48, 189.

elliptic interference with reflect-
ing grating, 50, 125.

transpiration of air through a

partition of water, 50, 117.

Base apparatus, 4, 368.

Basic lines, harmonies of Lockyer's,

18, 224.

Basin, tertiary strata of the great,

19, 60.

Bates-Miiller hypothesis. 43, 393.
Bathmodon, 12, 417.
Batrachia, 12, 41 ; 16, 573, 666; 17,
505; 22, 405; 24, 273.

— of the coal measures of Ohio, 16,
573: 22, 405.

— and reptilia, synopsis of the,
obtained in the Province of Mato
Grosso, Brazil, 24, 44.

-of Costa Rica, 31, 323.

Batrachian fauna of the Carbonifer-
ous of Linton. 12, 177.

— footprints in anthracite, 17, 716.
Batrachians and Reptiles, catalogue

of the species of, in a collection
made at Pebas, Upper Amazon,
23, Q4-

/.

PROCEEDINGS. VOLS. 1-50

BATRACH-BLAS

Batrachians and reptiles (continued).

of Grand Cayman, 24, 273.

Bauer, L. A., solar activity and ter-
restrial magnetic disturbances, 49,
130.

Baur, George, taxonom}- of the genus
Emys, C. Dumeril, 30, 40, 245.

Testudinata, 31, 210.

Beadle, Elias R., obituary notice of
D. Hayes Agnew, 22, 227.

Beads from Indian graves, 11, 369.

Bean, Coregonus nelsonii, 43, 451.

Bear River Group, sections of strata
of, II, 420.

Becker's aneroid, 7, 342.

— ■ self-registering combined ther-
mometer and barometer, 7, 339.

Beegerite, cosalite. alaskalite and,
22, 211.

Bell, John, obituary notice of Charles
D. Meigs, 13, 170.

Benedict, Francis G., influence of
mental and muscular work on nu-
tritive processes, 49, 145.

Benzoic acid, conversion of. into
hippuric acid, 3, 129.

Beothuk Indians, 22, 408; 23, 411;
28, I.

Bergey, D. H., influence of alcoholic
intoxication on haemolysis and bac-
teriolysis, 41, 140.

Berkshire, ^lass., geology of, 2, 3.

Berry, Edward W., tertiary floras of
the Atlantic and Gulf Coastal
Plain, 50, 301.

Beryllium borate, 17, 706.

Bessel, F. \V.. motions of Procyon
and of Sirius. 4, 112.

Bethune. George W.. obituary notice
of Robley Dunglison. 9, 70.

observations on ethnologv, 4,

.358.

Betoya dialects, notes on. 30, 271.

Biddle, Alexander, obituary notice of.
Memorial Vohiiiie, i, 196.

Biddle. Clement C. obituary notice
of. 6, 158.

Biddle, Craig, obituary notice of
Caspar Wister, 26, 492.

Biddle, John B., obituary notice of
Nathaniel Chapman, 7, 397.

Biela's comet, 4, 235. 241.

and the large meteors of Nov.

27-30. 1887. 24, 242.

Bielids, possible existence of fire-
balls and meteorites in the stream
of. 24, 436.

Big Horn region, geological explor-
ation of, 19, 650.

Binne}'. Horace, obituary notice of,

16, I.

Binney, Horace, Jr., obituary notice
of, II, 371.

Birdhawal Tribe, in Gippsland, Vic-
toria, language of the. 46, 346.

Birds of Santa Clara Count}-. Cal.
38, 157-

Bismuth and tellurium, 14, 223.

Bitumens, genesis of, 10, 445.

— — as related to chemical geology.
37. 108.

Bituminous material from Pulaski.
Co., Va., 17, 215.

Blair. William R.. exploration of
upper air by kites and balloons,
48, 8.

Bland Co.. Va., geological reconnais-
ance of. 24, 61.

Bland. T., physical geography and
geology, and distribution of ter-
restrial moUusca in certain of the
West India Islands, 12, 56.

Blasius, William, cause of the Huron
disaster, 17, 212.

meteorology, 16, 198.

, — and health, 14, 667.

modern meteorological methods,

17, 278.

progress of meteorology in the

last twenty-five years, 16, 394.

remarkable sun glows in the

Fall of 1883 and 1884, 22, 213.

Signal Service Bureau, its meth-
ods and results, 24, 179; 26, 285.

BLINDNESS-BOYE

GENERAL INDEX

Blindness from congenital malforma-
tion of the skull, 41, 161.

Blodget, Lorin, atmospheric physics
and climatology, catalogue of
works on, 32, 248.

Blasius' opinions in meteorol-
ogy, 16, 205.

clays under Philadelphia, 16,

780.

downward atmospheric circula-
tion causes extreme cold, 14, 150.

electricity as a motor, 34, 8.

industrial migration, 19, ;o.

-non-periodic distribution of heat

in the atmosphere. 13, 138.

atmospheric physics and clima-
tology, catalogue of works on — ,
32, 248.

■ silver ore from Pennsylvania,

17, 728.

Blood from dogs, 6, 243.

Blood, human and animal, specific
precipitins and their medico-legal
value in distinguishing, 41, 407.

Blue Mountains, ice erosion on, 20,
468.

Blum, William and Edgar F. Smith,
cathodic precipitation of carbon,
46, 59.

Blunt, Edmund, solar eclipses of
May 4, 1836, and September 18,
1838, I, 177.

Boas. Franz, ethnology of British Co-
lumbia, 24, 422.

Kwakiutl vocabulary. 31, 34.

Salishan texts, 34, 31.

'J'lingit, Haida, etc., languages,

29, ^73-
Boat, steam canal, 4, 121.
Bolivia, explorations in, 19, 564.
Boltwood, Bertram B.. radioactivity.

50, 3.33-
Bonaparte, Joseph, obituary notice

of, 6, 71.
Bond, Henry, spina bifida, 4, 124.
Bones, dermal, of Paramylodon, 49,

191.

Bonnycastle, Charles, experiments to
determine the depth of the sea, by
the echo, i, 39.

— — fluids in motion, i, 191.
Bonwill, William, obituary notice of,

Memorial Volume, i, 206.
" Book of the Dead," fragment of

the, 38, 79-
Booth. James C, obituary notice of,

25, 204.

— and Boye. conversion of benzoic
acid into hippuric acid, 3, 129.

Borax, California, 9, 450.

Borden, Simeon, comparison of the
dimensions of the earth with mean
determinations, 3, 130.

— ■ — ■ Hassler's criticism of the Mas-
sachusetts Survey, 2, 164.

Trigonometrical Survey of Mas-
sachusetts, 2, 60.

Boric acid, determination of, 24, 429.

Boring records in the anthracite
region, 11, 107. 235.

Borneo, glimpses of, 35, 309-

Bosnien und der Hercegovina, 23,

87.
Bostrichidc-e of the United States,

17, 540.
Botanique fossile, cours dc, by Prof.

M. B. Renault, 19, 287.
Botanists, early, of the Society, 18,

535-
Botocudus and their ornaments, 26,

171.

Bottosaurus. 11, 367.

Boundary, North-East. 4, 53.

Boxing, dynamics of, 33, 179.

Boye, Martin H., analysis of feld-
spar, 2, 53.

concretion found in a horse's

stomach, 4, 230.

conversion of benzoic into hip-
puric acid, 3, 129.

decay of articles deposited in

corner-stones, 5, 323, 325.

new compound of platinum, i,

94.

PROCEEDIXGS, VOLS. 1-50

BOYE-BRINTON

Boye (continued).

perchlorate of oxide of meth-

ule, 2, 202.

Protococcus Nivalis, 5, 262.

— • — vibrations caused by heat, 6, t,2.
and Clark Hare, perchloric

ether, i, 261.
Brachiopods, embryology of, 41, 41.

— genus Rensselaria in the Hamil-
ton group. Perry County. Pennsyl-
vania, 21, 235.

Bradford oil sand, 18, 419.

Brain and auditory apparatus of a

thermomorphous reptile of the

Permian Epoch, 23, 234.

— of one-half average weight from
an intelligent white man, 49, 188.

Brains of eocene mammalia, Phen-
acodus and Periptvchus, 20, 509,
563.

— of natives of the Andaman and
Nicobar Islands, 47, 51.

Branner, John C, Botocudus and

their ornaments, 26, 171.
■ hbro-vascular bundles in palms,

21. 459-
glaciation in \\'\oming and

Lackawanna Valleys, Pa., 23, 2)^7-
Brazil, vertebrate paleontology of,

23, I
Breck. Samuel. Continental money,

I, 24S; 3, 57; Hiit. and Lit.

Trans., 3, 3-
Bremiker's comet, 4, 86.
Brewster's neutral points, 10, 223.
Brezina, Aristides, arrangement of

collections of meteorites, 43, 211.
Bridge truss, relation between the

economic depth of a, and the

depth that gives greatest stiffness.

44. 164.
Bridges. Robert, obituary notice of,

21, 427-
Briggs, Robert. construction of

domes, 10, 379.
deviating forces of a fly-wheel,

17, 126.

Briggs (continued).

dispersion of heat generated by

a gas burner, 17, 309.

— — flow of w^ater through an open-
ing in a pierced plate, 16, 310;
17, 124.

fuel from coal dust, 10, 290.

— — gold extracting machinery, 10,
29.

— — health and ventilation, 10, 8.
patent to prevent incrustations,

10, 169.

'Pennsylvania oil region, 10,

109.

on the screw, 9, 278.

reserved power in rolling-mill

machiner}-, 9, 228.

Brinton, Daniel G., Alaguilac lan-
guage of Guatemala, 24, t,66.

ancient footprint from Nica-
ragua. 24, 437.

— — Andagueda dialect of the Choco
Stock, 34, 401.

Arval Brethren, Etrusco-Libyan

elements in the song of the, 30,
317.

Beloya dialects, ^o, 271.

— — bibliography of, Memorial Vol-
ujiic. I, 247.

Cakchiquel language of Guate-
mala, 21, 345.

Central American native calen-
dar. 31, 258.

Chinantec language of ^Mexico,

30, 22.

Choctaw, grammar, 11, 317.

conception of love in some

American languages, 23, 546.

Diego de Landa's writings, 24,

I.

ethnologic affinities of the

ancient Etruscans, 26, 506.

— — Etruscan and Libyan names,
comparative study on, 28, 39.

— • — Etrusco-Libyan elements in the
song of Arval Brethren, 30, 317.

BRINTON-BROOKS

GENERAL INDEX

Brinton, Daniel G. (continued).
— ■ — evolution, organic, 35, iii.

— — Euegian languages, 30, 249.
Guetares of Costa Rica, ethnic

affinities of, 36, 496.

ikonomatic method of phonetic

\vriting, with special reference to
American archaeology, 23, 503.

lineal measures of the semi-
civilized nations of Mexico and
Central America, 22, 194.

linguistic cartograph_v of the

Chaco region, 37, 178.

■ Alangue, an extinct dialect for-
merly spoken in Nicaragua, 23,
238.

■ Matagalpan linguistic stock of

Central America, 34, 403.

Maya language 11, 4.

— • — Mazatecan language of ]\lcxico.
30, 3T.

— — memorial meeting in honor of,
Memorial J'olniiic, i, 210.

Mosquito Coast, vocahularies

from the. 29, i.

Muskokee language, 11, 301.

Nagualism, study in American

folk-lore and history, 33, 11.
names of the Gods in the Kiche

myths, 19, 613.

Nanticoke dialect, 31. 325.

Natchez language, 13, 483.

Noanama dialect of the Choco

stock, 35, 202.
obituary notice of. Memorial

J'olitmc. I, 221.
■ , — — of S. S. Haldeman, 19,

279.

, Isaac Hays, 18, 259.

, — ■ — Henry Hazlehurst. M emu-
rial Volume, I, 18.
, George de Benneville

Kcim, 33, 187.
, Philip H. Law, 25, 225.

— — , John Neill, 19, 161.

, — — W. S. W. Ruschenbcrger,

34, 361.

Brinton, Daniel G. (continued).

— palseolithic man, language of, 25,
212.

-philosophic grammar of Amer-
ican languages, as set forth by
Wilhelm von Humboldt, 22, 306.

■ poiysynthesis and incorporation

as characteristics of American lan-
guages. 23, 48.

— ■ — • protohistoric ethnography of
Western Asia, 34, 71.

Puquina language of Peru. 28,

242.

— • — song of the Ar\al Brethren.
30, 317

^ South American native lan-
guages, 30, 45.

• — — Ta Ki. the Svastika and the
Cross in America, 26, 177.

thought as function, measure-
ment of, 36, 438.

— ■ — -Valentini's theory of the Mex-
ican Calendar Stone, 14, 663.

verl) in American languages, 22,

vocabularies from South Amer-
ica, two unclassified, 37, 321.

were the 'i'oltecs an liistoric

nationality?. 24, 229.

Xinca Indians of Guatemala.

language and ethnologic position
of, 22, 89.

Britton, J. Blodgett. burettes, im-
proved, 16, 192.

— —forms in which carbon exists
in iron and steel, 17, 712.

— • — peat and lignite, Arkansas, 20,

225.
. — American condensed, 16,

656.

Rocky Mountain coals, 14, 358.

Brockway, E. B., thermometrical

observations in Quito, 21, 676.
Brooks. Charles Edward. orthic

curves : or algebraic curves which

satisfy Laplace's equation in two

dimensions, 43, 294.

10

PROCEEDIXGS, VOLS. 1-50

BROOKS-CAPE

Brooks, William Keith, heredity and

variation, 45, 70.
is scientific naturalism fatalism ?,

41, 145-

new genus of hydroid jelly-
fishes, 42, II.

obituary notice of, 47, i.

Brown, Amos P., crystallographic
study of the hemoglobins, 47, 298.

-pyrite and marcasite, 33, 225.

Brown. Samuel, apparent isomerism,

2, 75-

Brown-Sequard, C. E., blood from

dogs, 6, 243.
Browne, Peter A., Saxony wool, 5,

259-
Brownian movements, secret of the,

33, 163-
Brownstone, age of the Newark, 33,

5.

Brush Alountain, structure and ero-
sion of, 13, 503.

Bryant, Henry G., drift casks in the
Arctic Ocean, 41, 154.

Bryce, Rt. Hon. James, obituary
notice of Henry Charles Lea, 50,
xxiv.

-personal reminiscences of

Charles Darwin, and of the recep-
tion of the '■ Origin of Species."
48, iii.

Buceros Scutatos, 9, 86.

Bufo and Rana, synonymic list of the
North American species of, 23,

514- ■

Burettes, improved, 14, 218; x6, 192.

Burial customs of the Australian
aborigines, 48, 313; 49, 297.

Bush, the burning, and the origin of
Judaism, 48, 354.

Buti, Rudolph, fragment of the
" Book of the Dead." 38, 79.

Butler, Howard Crosby, Princeton
University Archaeological Expedi-
tion to Syria, 46, 182.

Butterflies, genealogical trees of, 38,

147-
Byington & Brinton, grammar of the
Choctaw language, 11, 317.

Cables, corrosion of, by sea water.

I, 70
Cadmium, electrolytic estimation of.

18, 46.
Cadwalader. John, obituary notice of

Charles Nicoll Bancker. 11, 85.
Cakchiquel language of Guatemala,

grammar of, 21, 345; 22, 255.
Calcium, electrolytic. 43, 381.

— extrication of. i, 130.

— metallic, i, 83, 100.

Calculus found in a deer, analysis
of, 18, 213.

Caldwell, Charles, obituary notice of,
6, 77-

Calendar. Central American Native,
31, 258.

— -new civil and ecclesiastical, 4, 192.

— -stone. Mexican. 14, 663.

California, fossils from. 11, 425.

Caloric engines for ships, 5, 305.

Calospasta Lee, notes on, 29, 99.

Cambala, revision of the Lysiopetali-
dx, a family of the Chiloquath My-
riopoda with a notice of the genus,
21, 177.

Cambarus, mutual afiinities of the
species, and their dispersal over
the LInited States, 44, 91.

Camel, introduction of, into the
LTnited States, 6, 275.

Canada, geology of the Western pen-
insula of LTpper, 2, 120.

— miocene fossils of, 22, 98.

Cannon, notes on, 50, 147.

Cannon, W. B., stimulation of ad-
renal secretion by emotional ex-
citement, 50, 226.

Canon City, coal field, 19, 505.
Cape Breton, aurora at, 9, 60.
coal beds. 9, 93, 165, 197, 208.

11

CAPIL-CHALLIS

GENERAL INDEX

Capillary action, i, 82; 4, iy6.

Car, ventilation of passenger, 43,

247.

Carbon, cathodic precipitation of, 46,

59-
— •conversion of the energy of, into
electrical energy on solution in
iron, 49, 49.

— in iron and steel, 17, 712.
— ■ role of, 43, 102.

Carbonates, alkaline, decomposition
of, 3, III.

Carbonic acid, decomposition of, and
the alkaline carbonates by the light
of the Sun, 3, in.

Carburetted hydrogen, roseate tint
imparted to light of, 4, 114.

Carbutt, John, Rontgen ray, 35, 33.

Carex Miliaris, note on the, 25, 320.

Carey and two of his critics, 29, 166.

Carey, Henry C, obituary notice of
Stephen Colwell, 12, 195.

Carleton, Henry, liberty and neces-
sity, 9. 131-

Carll, John F., oil well records, 16,
346, 429.

results of Pennsylvania rail

road and oil well surveys, 17, 17.

Carnivora, claw-footed, of Wyoming-
eocene, 13, 198.

— eocene, 20, 226.

Carollia, new species of, 28, 19.
Carpenter's square, improvement on,

6, 169.
Carrel, Alexis, transplantation of

organs, 47, 677.
Carriages, springs for, 3, 106.
Carson, Hampton L., obituary notice

of Gen. A. A. Humphreys, 22, 48.
Carter, Jesse Benedict, evolution of

the city of Rome from its origin to

the Gallic catastrophe, 48, 129.
Carter, Oscar C. S., adulterations in

oil, 22, 296.
feldspar bed in Laurentian (?)

gneiss, 29, 49.

Carter, Oscar C. S. (continued).
and J. P. Lesley, artesian wells

in Montgomery and Philadelphia

Counties, 29, 43.
Carthagenian tombstone, 38, yz, 12,.
Cartography, linguistic, of the Chaco

region, 37, 178.
Casks, drift, in the Arctic Ocean,

41, 154-
Cat, accessory nerve in, 25, 94.

— brain of, 19, 524.

— facial nerve in, 24, 8.

— glosso-pharyngeal nerve in, 25, 89.

— hypoglossal nerve in, 25, 99.

— trigeminus nerve in, 23, 459.

— vagus nerve in, 20, 123.
Cathode, mercury, in electro-analysis,

44. 137.
Catskill and Ponent formation not
equivalent, 20, 673.

— rocks, mass of, supposed to exist
on the north bank of Towanda
creek near Franklin, 20, 531, 533.

CattcU, William C, study of lan-
guages, 18, 543.

Cave, Port Kenedy bone, 12, 15, "z:^.

Cayman, Grand, reptiles and batrach-
ians of, 24, z-j^,-

Centennial address, 3, 3.

Central force, 16, 298; 17. 98.

Centres, aggregation and dissociation,
16, 496.

— controlling, 18, 429.
Ceratocampidae, Hemileucidae, &c.,

life histories of certain moths of

the families, 14, 256; 31, 139.
Cetacea, classification of, 47, 385.
Chabas, Frangois J., footmark in

hieroglyphic script, 12, 193.
Chadd's Ford, primary limestone

near, 8, 281.
Chalfont fault rock, so called, 34,

3S4.
Challis's laws of molecular action and
the laws of attraction and rotation,
9, ^<^7-

12

PROCEEDINGS, VOLS. 1-50

CHAMB-CHASE

Chamberlin, Thomas C, possible re-
versal of deep-sea circulation and
its influence in geologic climates,

45, 33-

Chance. Henry ]\Iartin, auriferous
gravels in North Carolina, 19, 477.

— — fire-damp explosions in Penn-
sylvania anthracite mines, 19, 405.

— ■ — Hyner's Station oil well section,
17, 670.

obituary notice of J. Peter Les-
ley, 45, I-

— ■ — -origin of bombshell ore, 47, 135.

Channel-way, re-eroded, 19, 84.

Channels, reaction, in procuring
deeper navigable, 42, 199.

Channing, \V. F., meteorological pe-
culiarities of New England, 14,

154-
Chapman. Nathaniel, obituary notice

of. 7, 397-

Charts, taxonomic, of the monocoty-
ledons and dicotyledons, 46, 313,

Chase, Pliny E., sethereal density and
polarity, 12, 407.

, — -oscillation, the primordial

material force, 12, 411.

American weather notes, 12, 40.

— • — ■ apparent semi-diameter of the
sun, and nebular origin of the ter-
restrial day, 18, 380.

— ■ — -approximations to sun's dis-
tance, 12, 398.

— - — astronomical approximations 18,
380, 425 ; 19, 4, 18, 20.

— • — beginnings of development, 14,
622.

-catalogue of tokens circulating

during the Rebellion, 9, 242.

centres of aggregation and dis-
sociation, 16, 496.

— ■ — • Chase-^Iaxwell ratio, 22, 375.

— - — chemical atoms, molecules and
volumes. 16, 505.

-Chinese analogues in other lan-
guages, 8, 5; 9, 145, 172, 231.

Chase, Pliny E., Chinese (continued).

-. — seal inscriptions, 9, 139, 144.

cometary paraboloids, 19, 18.

— - — comparative fitness of languages
for musical expression, 9, 419.

, — visibility of Arago's, Babi-

net's. and Brewster's neutral points,
in Philadelphia and its neighbor-
hood, 10, 223.

— - — comparison of mechanical equiv-
alents, II, 313.

, — of planetary series, 13, 471.

, — of solar and lunar magnetic

and aereal tides, 9, 487.

component elements of normal

barometric tides; influence of oscil-
lations moving with the velocity of
light. 9, 405.

— ■ — controlling centres, 18, 429.-

Copto-Egyptian vocabulary, 10,

69.

-correlations of cosmical and

molecular force. 12, 392.

, — of gravity with the vertical

deflection of the needle, 10, iii.

— - — , — of planetary mass, 13, 239.

^correspondence between Chal-

lis's laws of molecular action and
the laws of attraction and rotation,
9, 367-

— - — cosmical determination of
Joules' equivalent, 19, 20.

— • — , — evolution, 14, 159.

— - and molecular harmonies,

13, 237.

— relations of light to gravity,
103.

— thermodynamics 14, 141.

— — ^ criteria of the nebular hypo-
thesis, 17, 341.

crucial harmonies, 18, 34.

cyclical rainfall, 12, 178, 523;

14, 195-

daily auroral and meteoric

means, 12, 516.
, — distribution of heat, 9, 345.

13

CHASE-CHASE

GExXERAL IXDEX

Chase, Pliny E. (continued).

discovery of certain new rela-
tions between the solar and lunar
diurnal variations of magnetic
force and of barometric pressure,

-diurnal variations of the barom-
eter, 9, 283.

— ■ — dynamic coordinations 14, 651.

• estimate of solar mass and dis-
tance from the equilibrium of elas-
tic and gravitating forces, 13, 142.

ethereal influences in the solar

system, 16, 496.

European and American rain-
fall, 12, 38.

evidences of lunar influence on

rainfall, 10, 436.

experiment in weather forecast,

22, 207.

Faraday's desideratum, 10, in.

-force which controls stellar-sys-
tems as well as molecular motions,
10, 97.

— -—formulation of hypothesis of
unity of elastic force, 9, 425.

— ■ — fundamental propositions of
central force, 16, 298; 17, 98.

gamuts of sound and light, 13,

149.

— • — -general relation of auroras to
rainfall, 12, 400.

— — gravitating waves, 14, 344.

— ■ — gravitation, 18, 41.

— - — -harmonies of cosmical rotation.
13. 243.

. — of Lockycr's "Basic Lines,"

18, 224.

-heat and attraction, 10, 97.

height of the tides, 9, 291.

Herschel-Stephenson postulate

12, 395-
influence of meteoric showers

on auroras, 12, 401.
, — of oscillations moving with

the velocity of light, 9, 405.
Jupiter-cyclical rainfall. 14, 193.

Chase, Pliny E. (continued).

kinetic ratio of sound waves to

light waves, 18, 425.

— — -laws regulating the distribution
and transmission of solar heat, 10,
309.

list of papers communicated to

the American Philosophical Soci-
ety to April 16, 1880, 19, 184.

lunar-monthly barometric vari-
ations : resemblances to daily baro-
metric fluctuations, 9, 395.

— — , — rainfall, 10, 436; 12, 558;
14, 416.

magnetism, some general conno-
tations of, 10, 368.

— - — - mechanical modification of elec-
tric and other elastic currents, 9,

355-
, — -polarization of magnetic

needles, 10, 151.
meteors, 10, 353, 3^-. 539: 12,

401.
— ■ — monthly rainfall in the U. S.,

11, 314; 12, 555.

music of the spheres, 13, 193.

nebular action in the solar sys-
tem, 16, 184.

nodal estimation of the veloc-
ity of light, 19, 4.

normal position of the tidal

ellipsoid, 12, 123.

— - — obituary notice of. 24, 287.

origin of attractive force, 14,

III.

oscillatory forces in the solar

system, 13, 140.

— — ^Philadelphia life tables. 11, 17.
— • — philosophy of Christianity. 18,

123.
photodynamic notes. 19, 203,

262, 354, 446, 567 ; 20, 237. 406, 566 ;

21, 120, 590.
— ■ — planetary illustrations of the

creative fiat. 14, 609.
— • — , of explosive oscillation.

12, 403-

'i

PROCEEDINGS, VOLS. 1-50 CHASE-CHEMUNG

Chase, Pliny E., planetar\- (con-
tinued).

, — node between Alercury and

Vulcan, 13, 252.

, — -relations to the sun-spot

period. 13, 147.

planeto-taxis, 13, 143.

polarizing influences of thermal

convection and radiation, 9, 367.

possible vowel sounds not used

in any language, 9, 271.

prediction of an "unknown

planet," 13, ^2>~-

— ' — -primitive names of the Su-
preme Being, 9, 420.

probabilities in etymology-, 10,

345-

quadrature of the circle, approx-
imate, 18, 281.

radiation and rotation, 17, 701.

radical significance of numerals,

10, 28.

rain guage curves, 11, 113.

recent confirmation of an as-
tronomical prediction, 13, 470;

18, 209.

relation of auroras to gravitat-
ing currents, 12, 121.

relations of chemical affinity to

luminous and cosmical energies,

19, 21.

, — of magnetic declination to

gravity, 10, 97.
, — — .gravitating and luminous

force, 14, 607.

, — of mass, 18, 229.

. — of temperature to gravity

and density. 10, 261.
— — relative velocities of light and

gravity, 13, 148.
resemblance of atmospheric.

magnetic and oceanic currents. 12,

68.
results of wave interference,

17, 294.
rotation of the sun and the

intra-asteroidal planets, 13, 145.

Chase. Pliny E. (continued).

■ Sanscrit and English roots and

analogues, 7, 177.

Saving Fund life insurance. 14,

148.

sky light polarization, 10, 151,

196.

solar records, 18, 224.

, — -and lunar diurnal variations

of magnetic force and of baromet-
ric pressure, 9, 425, 487.

, planetary rotation, 12,

406.

-specific magnetism of iron, 10,

358.

-spectral estimates of sun's dis-
tance, i8, 227.

stellar and planetary correla-
tions, 12, 518.

sun-spot cycle of 11.07 years,

12, 410.

terrestrial magnetism as a me-
chanical agent, 9, 427.

thermo-electro-photo-baric unit,

22, zil-

tidal rainfall, 10, 523; 11, 202.

transcript of a curious ms. work

in cypher, supposed to be astrolog-
ical, 13, 477.

velocity of light and Kirk-
wood's analogy, 18, 425.

weather study. 13, 248.

winds of Europe, 12, 123.

of the United States, 12, 65,

\-early rainfall in U. S.. 14, 613.

Chase-IMaxwell ratio, 22, 375.

Cheat River Canon, geology of. 20,

479-
Chemical affinity, relation of, to
luminous and cosmical energies,
19, 21.

— analysis chromatic, 18, 211.

— atoms, molecules and volumes, 16,
505-

Chemung rocks, revision of the sec-
tion of, at Leroy, Bradford County,
Pa.. 23, 291. 304.

15

CHEVALIER-CLAYS

GENERAL INDEX

Chevalier, Michel, obituary notice of,

19, 28.
■ railway under the English

Channel, survey for, 17, 283.
Cheyney, Edward Potts, obituary

notice of Henry Charles Lea, 50,

V.

Children, male, excessive mortality
of, 4, 212.

Chilopoda, Myriapoda INlusei Canta-
brigensis, Mass., 23, 161.

Chimaerid from New Jersey, 11, 384.

Chinantec language of Mexico, 30,
22, 108.

Chinese analogues in other lan-
guages, 8, 5; 9, 145, 172, 231.

■ — seal inscriptions, 9, 139, 144.

• — writing, i, 120; Trans. Historical
and Literary Comm., 2, i.

Chiriqui images, 7, 162.

Chlorine, conversion of, into hy-
drochloric acid, 21, 102.

— derivatives from toluol, 16, 667;
17, 29.

Choctaw language, grammar of, 11,

317-

Christianity, philosophy of, 18, 129.

Chromatin, spermatogenesis of Onis-
cus asellus Linn., with especial
reference to the history of, 41,

77-

Chromic iron, decomposition of, 17,
216.

Chromometry, 18, 29.

Chrysocolla from Chile, new variety
of, 48, 65.

Circle, approximate quadrature of
the, 18, 281.

Circulation, deep-sea, possible rever-
sal of, in its influence on geo-
logic climates, 45, :iZ.

' — downward atmospheric, causes ex-
treme cold, 14, 150.

Civil Service Reform, need of, 18,

559.
Clark, TTeber R., coal oil, 9, 56.

Clarke, F. W., statistical method in
chemical geology, 45, 14.

Claypole, E. W., Clinton and other
shales composing the fifth group of
Rogers in the first survey of Penn-
sylvania, 21, 492.

equivalent of the New York

Portage in Perry County, Pennsyl-
vania, 21, 230.

, — of the Schoharie grit of New

York in ^Middle Pennsylvania, 20,

534-
error in identifying two distinct

beds of iron ore in Report G. of

the Gcol. Survey in Bradford Co.,

20, 529.
fish-plate in the upper Chemung

beds of northern Pennsylvania, 20,

664.

— — fossil forms, commingling of,
20, 477.

genus Rensselaria in the Hamil-
ton group. Perry County, Pennsyl-
vania, 21, 235.

-geological notes. 20, 529.

-Kings Mill white sandstone, 20,

666.

large crustacean from the Cats-
kill group of Pennsylvania, 21, 236.

■ mass of Catskill rocks supposed

to exist on the north bank of
Towanda Creek near Franklin, 20,

531-
— • — occurrence of the Holoptychius

in the Chemung group, in Bradford

Co., 20, 531.
-organic variation indefinite not

definite in direction, 24, 113.

— — Perry County faults, 21, 218.

relic of the native flora of Penn-
sylvania, surviving in Perry
County, 21, 226.

two small patches of Catskill

represented near Leroy. on the Map
in Report G, of the 2nd Geological
Survey of Penna., 20, 533.

Clays under Philadelphia, 16, 180.

16

PROCEEDIXGS. VOLS. 1-50

CLEEM-COLOR

Cleemann, Thomas Mutter, obituary

notice of, 33, 177.
Clitoris, 4, 129.

Clock, new telegraphic, 5, 51, 206.
Cloud, cumulus, formation of, from

the action of a fire, 2, 116.

— levels, 2, 187, 190.

Coahuila, its geography and ethnol-
ogy, 16, 561.
Coal areas, estimation of, 20, 232.

— basin, Cumberland, 11, 9; 19, 11 1.
— ^bed in the Joggins and Albert

Mine regions in Nova Scotia, 9,

459-

Upper Freeport, West Va., 19,

276.

— beds, alleged parallelism of, 14,
283.

formation of, 50, i, 519.

of Cape Breton, 9, 165. 20S.

— • — -of Somerset County, Pa., 14,
157-

— borings in Wilkes-Barre Basin,

11. ^35-

— deposits, near Zacualtipan, in Hi-
dalgo, Mexico, 23, 146.

— dust, fuel from, 10, 290.

— field, Cafion City, Colorado, 19,

505-

outcrop belt of East Kentucky,

13, 270.

— fields of the Indian Territory, geo-
logical reconnaissance of, 36, 326.

— flora, American, 9, 198.

— measure sections near Peytona,
West Virginia, 33, 282.

— -measures on Cape Breton coast,
9, 93. 167.

— oil, 9, 56.

— • system of southern Virginia, 9, 30.

— tertiary, &c., of Osino, Nevada,

12, 478.

— waste, apparatus to consume an-
thracite, 16, 214.

Coals, character of some Sullivan

Count}-, 18, 186.
— 'Rocky [Mountain, 14, 358.

Coates, Benjamin H., effects of se-
cluded imprisonment on Africans
in production of disease, 3, 3;
Trans. Hist, and Lit. Comm., 3, 85.

— ■ — -Hessian fly, 2, 42.

lake dwellings, &c., 9, 414.

— - — obituary notice of Charles Cald-
well, 7, 77.

, of John Reynell, 7, 156.

Cobitidae in Idaho, fossil, 12, 55.

Cochin-chinese language, vocabulary
of the. Trans. Hist, and Lit.
Comm., 2, 125.

Cochin-Sinense Latinum ad usum
missionum, lexicon. Trans. Hist,
and Lit. Comm.. 2, 185.

Cochliopodidffi, life history of certain
moths of the family, 31, 83.

Cocoon, specialized, of Telea poly-
phemus, 41, 401.

Codex Ramirez, 21, 616.

Cohesion of liquids, 4, 56, 84.

Coin, copper, 10, 270.

— -supposed, found in Illinois, 12^
224.

Coins, Japanese, and Austrian money,
8, 264.

— -metallic, 5, 198.

— silver, from the wreck of the;
" San Pedro," 4, 200.

of the Mint, 11, 233.

— notes on, 18, 191, 327.
Coinage, 6, 95, 106.

Cold, downward atmospheric circu-
lation cause of extreme, 14, 150.

Coleoptera, arrangement of the fam-
ilies of. 13, 75.

— of Florida, 17, 353, 434.

— of Michigan. 17, 593, 627, 643.
— -Schwartz's, 17, 470.

Collieries, anthracite, map of, 13,

155-
Colombian guano. 6, i8g.
Color in plants, 43, 257.

— plea for Governmental supervision
of ports necessitating normal per-
ception of, 44, 40

17

COLOR-COPE

GENERAL INDEX

Color-blindness, i, 265.

Colorado, geology of, 10, 463; 11,

15, 212, 234, 431.
— , Wyoming and, 10, 463; 11,

15, 431.
Columbium, observations on, 44, 151,

177.
Columella and stapes in some North

American turtles, 17, 335.
Colwell, Stephen, obituary notice of,

12, 195-

, -Isaac R. Davis, 6, 299.

Colydiid?e of the United States, 17,

555-
Comet, Biela"s, 4, 235, 241.

— Bremiker's, 4, 86.

— Encke's 2, 90, 160, 182, 186, 201.

— Galle's, I, 216, 275, 301.
— , — second, i, 275.

— Halley's, spectroscopic proof of the
repulsion by the sun of gaseous
molecules in the tail of, 50, 254.

— Mauvais', 4, 67.

— of 1840, 2, 75.

— of 1843, 2, 267, 270, 2-J2, 275; 3, 67,
•152.

=-^ of 1866, and the meteors of No-
vember 14, 22, 424.
Comets and meteors, 11, 215.

— polarized light of, 6, i},;},.

— -tails of, constitution and mode of
formation of, 3, 108.

Compass, convenient device to be ap-
plied to hand, 22, 216.

Comstock. Daniel F., modern theory
of electricity and matter, 50, 321.

Concept, straight line, 44, 82.

Concretion in horse's stomach, 4, 230.

Condenser, electrometric measure-
ment of the voltaic potential differ-
ence, between the two conductors
of a, containing a highly ionized
medium, 48, 189.

Conducting power of bodies for heat,
instrument to determine, 3, 132.

Congo Independent State, account of,
26, 459.

Conklin, Edwin G., emliryology of a

Brachiopod, Terebratulina septen-

trionalis Couthony, 41, 41.
— — -factors of organic evolution

from the embryological standpoint,

35, 78.
obituary notice of William Keith

Brooks, 47, i.
world's debt to Darwin, 48,

xxxviii.
Cooper, J. G., land shells of the

Pacific slope, 18, 282.
Coordinations, dynamic, 14, 651.
Cope, Edward D., Adocidse, 11, 547;

17, 82.

Adocus, II, 295.

■ Amphiumidae, structure and

affinities of the, 23, 442.

Archsesthetism, 20, 232.

Artiodactyla. classification of

phylogeny of the, 24, t,'j~ .
, — structure of feet in extinct,

22, 2.1.
— • — - Astaci from fresh water ter-
tiary of Idaho, II, 605.
— • — • Asteracanthus, 11, 440.
Australian and Maori skulls,

II, 446.
— - — • Balsenoptera Cope, 12, 108.

Bathmodon, 12, 417.

batrachia, living, from Peru,

16, 666.
, — of the Ohio Coal Measures,

16, 573; 22, 405.
■, — and reptilia oljtained in ■Nlato

Grosso, Brazil, 24, 44.
, — - — contained in a collection

made at Pebas, Upper Amazon,

23» 94-

, — — of Costa Rica, 31, ZZZ-

, of Texas Permian, 17,

505-

batrachian fauna of the Linton

(O.) Carboniferous, 12, 177.

— ■ — - Big Horn region, geological ex-
ploration of, 19, 650.

• Bottosaurus, 11, ^(yj.

18

PROCEEDINGS, VOLS. 1-50

COPE-COPE

Cope. Edward D. (continued).

Bufo and Rana, synonymic list

of North American species, 23, 514.

Carnivora Fissipedia, systematic

relations of, 20, 471.

-Carnivorous animals, structure

of some Eocene, 20, 226.

Chimjerid from New Jersey.

II, 384-

claw-footed carnivora of Wyo-
ming Eocene, 13, 198.

coal, &c., of Osino, Nevada,

tertiary, 12, 478.

. — deposits near Zacualtipan,

in Mexico, 23, 146.

cobitidae in Idaho, fossil, 12, 55.

Coryphodon, brain of, 16, 616.

Cotylosauria, 34, 436: 35, 122.

creation of organic forms,

method of, 12, 229.

Creodonta, genera of, 19, "jd.

dentition of the Amblypoda,

mechanical origin of, 25, 80.

— ■ — -Dicotylinae of the John Day
Miocene, 25, 62.

• Dinosauri in Wyoming transi-
tion beds, 12, 4S1.

— — ^ Dinosaurian Lcclaps Incrasatus,
skull of the, 30, 240.

Dinosaurus from Utali Trias,

16, 579-
^ Elasmobranch genus Didymo-

dus. structure of the skull in, 21,

572.
^ — elbow joints, false, 30, 285.
Eocene mammalia, Phenacodus

and Periptychus, brains of, 20,

509, 563.
Etheostomine perch, 11, 261.

— — evolution, outline of the philos-
ophy of, 26, 495.

fauna of the Eocene and Mio-
cene of the U. S., II, 285.

, — of North America, marine

Miocene, 34, I35 : 35, I39-

. — of Oregon Miocene. 18,

63. 370.

Cope, Edward D., fauna (continued).
— • — , — ^ of the Permian of Texas and

Indian Territory, 22, 28.

, — of Puerco Eocene, 20, 545.

fishes, fossil, 11, 316.

— • — . — ■ fresh water tertiary, of

Idaho, II, 538.
, — from Kansas Cretaceous, 12,

i27\ 17, 176.
, — Green River, Wyoming

Territory. 11, 370, 3S0.
, — .North Carolina fresh water

II, 442, 448.
, — obtained by the Naturalist

Expedition in Rio Grande do Sul,

ZZ, 84.

, — Permian Amazon, 17, 673.

. — of the United States, Cre-
taceous, II, 240.
-foramina perforating the poste-
rior part of the squamosal bone of

the jMammalia, 18, 452.
fossils from West Indies Island

caves, II, 608.
geology, contributions to,

Memorial Volume, i, 303.
Great Basin, tertiary strata of

the, 19, 60.
• herpetological and ichthyolog-

ical contributions. Memorial I'ol-

timc, I, 274.

herpetology of ^lexico, 22, 379.

— • — ; — of tropical America, 11, 147.

496. 513. 553; 17, 85; 18, 261; 22,

167: 23, 27'r.
— ■ — ■ hippotherium, review of the

North American species of, 26,

429.
horses from the Upper [Miocene,

two new species of three-toed,

with notes on the fauna of the

Ticholeptus beds, 23, 357.
■ Hyrachyus, osteology of the

extinct Tapiroid, 13, 212.

Hyrtl's collection. 12, 191.

— ■ — ichthyology of Alaska. 13, 24.
— — , — of the Antilles, 11, 514.

19

COPE-COPE

GENERAL INDEX

Cope, Edward D., ichth3ology (con-
tinued).
, — of the Maranon, 9, 496, 599;

11, 559-

, — of Utah, 14, 129.

■ Ichthj-opterygia, 11, 497.

Tguaninse, on species of, 23, 261.

jaw, lower, from the Colorado

Basin, 20, 199.

Lacertilia, osteology of, 30, 185

— ■ — Liodon Perlatus, ii, 496.
-Loup Fork formation in New

Mexico, distribution of, 21, 308.

— ■ -letter from, 21, 216.

■ Lystrosaurus Frontosus, 11,

370, 419-
— ■ — mammal, new synthetic form of

Laramie Cretaceous, 20, 476.
— • — -Mammalia, classiiication of L'n-

gulatc, 20, 438.
, — in the caves of the United

States, extinct, 11, i~i.
— ■ — -, — of the lowest Eocene beds

in New Mexico, 19, 484.
, — of the Valley of ^Mexico,

extinct, 22, i.
, — ^ some Pleistocene, from

Petite Anse, La., 34, 458.
mammals, extinction of fossil,

20, 643.
, — , work in the. Memorial

J'oh.nnc, i, 296.

man in Oregon, early, 17, 292.

marsupial from lower Eocene

of New Mexico, new, 20, 232.
Megaptera Bellecosa, 11, 516;

12, 103.

— — memorial meeting in honor of,

Memaria! I'olume. i, 2-;^,.
Metalophodon, dentition of, 12,

542.
■ — - — -molar tooth in the mammalia,
on the Tritulierculate type of. 21,

324-

• Mososaurus Brumbyi, li, 497.

, — Maximus, 11, 571.

Mvlodon Annectens, 11, 15.

Cope, Edward D., Mvlodon (con-
tinued).

, — teeth and ungual phalanges

of, 34, 350.

Ophidia, lungs of, a, 217.

— — Oreodontidse, synopsis of the
species of, 21, 503.

Ornithosaurians from Kansas,

new, 12, 420.
Perissodactyla, systematic ar-
rangement of the order, 19, t^jj.
■ Perissodactyles from the Bred-

ger Eocene, new, 13, 35.
— • — -Permian form from Texas,

new, 20, 405.
pliilosophy, remarks on Price's

phases of modern, 12, 317.
— - — Physostomi of the Neotropical

region, extinct forms of. 12, 52.
Plagopterinae and ichthyology of

Utah, 14, 129.

— — Pleurodira from Wyoming
Eocene, 12, 472.

Poebrotherium, 14, no.

■ populations in Eocene, north-
western New Mexico, remains of

14, 475-

Port Kenedy bone cave, 12, 15,

7i-
— • — - Proboscidiah, new, 16, 584.
Procamelus Occidentalis, brain

of, 17, 49-
^ Protostega, 12, 422.

— — Puerco epoch, 21, 309.

Pythonomorpha, found in the

cretaceous strata of Kansas and
New Mexico, 11, 574; 12, 264.

Rana, synonomic list of North

.\merican species of, 23, 514.

— - — -reptile, new Mosasauroid, 11,
116.

, — , Thcromorphous, of the Per-
mian epoch, structure of brain and
auditory apparatus of a, 23, 234.

reptiles, &c., from the Austrori-

parian region of the United States,
17, 63.

20

PROCEEDINGS, VOLS. i-:;o

COPE-COPE

Cope, Edward D.. reptiles (con-
tinued).

, — from Kansas cretaceous No.

3. 17. 176.

Reptilia. homologies of the pos-
terior cranial arches in the, 30,

III, 112.

, — cretaceous, of U. S., 11, 271.

. — of the Triassic formation of

the Atlantic region of the U. S.,

II. 444-

, — Plesiosaurian, 1 structure of

the skull in the, and on two new
species from the Upper Cretaceous,
33, 109.

— — , — and Batrachia of North
America, extinct, 12, 41.

reptilian remains from the Da-
kota beds of Colorado. 17, 193.

John A. Ryder, obituary notice

of, Memorial Volume, i, i.

Saurians in Pennsylvania, Tri-
assic, 17, 231.

■ Saurocephalus of Harlan, 11,

608.

Saurodontidse, 11, 529.

skeletons found near Wood-
bury, N. J., II, 310.

Smoky Hill River, Kansas, ex-
pedition to, 12, 174.

-snakes, analytical table of the

genera of, 23, 479.

stone implements found near

Potomac River, 31, 229.

Tapiroid hyrachyus, osteology

of, 13, 212.

• ■ Testudinate from the Kansas

Chalk, new, 12, 308.

Tiaporus, a new genus of Teii-

dfe. 30, 132.

Tomiopsis. on genu?, 31, 317.

Tortoises, cretaceous, 11, 16,

515-

-Toxodon, structure of the pos-
terior foot of. 19, 402.

— ■ — Ungulata from the Wyoming
Eocene, short footed, 13, 38.

Cope, Edward D. (continued).
■ vertebrata from -Bridger Eocene

of Wyoming, new, 12, 460. 468,

469.
— -— . — of the Dakota epoch of

Colorado. 17, 233
. — of eastern Illinois bone bed,

17. 52.
— • — . — in Kansas State Agricultural

College, cretaceous, 12, 168.

— — . — of the Lower Eocene of Wy-
oming and New ^Mexico. 188 1. 20,
139-

— • — , — of New Jersey INliocene. 14,
361.

•. — .new Paleozoic, from Illi-
nois, Ohio and Pennsylvania. 36,
/I-

, — in North Carolina, distribu-
tion of certain extinct. 12, 210.

. — -from northern part of the

Tertiary Basin of Green River. 12,
554.

. — from Permian Eormation.

Texas, 19, 27, 38; 20, 447, 628.

-, — — and Triassic formations of

the U. S.. 17, 182, 269.

. — from Peru, cold blooded, 17,

. — , phylogeny of the. 30, 278.

— • — . — . some new and little-known
Palsozoic. 30, 221.

. — .some points in the kineto-

genesis of the limbs of, 30, 282.

. — .synopsis of Puerco Eocene,

20, 461. 478.

. — of the Trias of North Amer-
ica. 24, 209.

, — from L^pper Tertiary forma-
tions of the west, 17, 219.

, — from upper waters of Bitter

Creek, Wyoming. 12, 483. 487.

. — • from the Wind River Eocene

beds of Wyoming, 19, 195.

— — vertebrate palaeontology of
Brazil. 23, i.

— ■ — , of Texas, 30, 123.

21

COPE-CRESSON

GENERAL INDEX

Cope. Edward D. (continued).
zoology of a pool, Colorado, 14,

139-
Copernicus, law of, 47, 18.
Copland, James, obituary notice of,

II, 525.

Coppee, Henry, flax culture, 9, 26.

obituary notice of, 34, 357.

, of Washington Irving, 12,

363.
, of O. McK. Alitchel, 9,

147-
Copper age in the United States, 9,

III, 119.

— coin, 10, 270.

— foil, action of, on certain intestinal
organisms, 44, 51.

— over slate horizon, 7, 329.

— with sodium carbonate, precipita-
tion of, 17, 218.

Coprolites, 3, 143.
Copto-Egyptian vocabulary, 10, 69.
Coral reefs, 2, 150.
Cordaites, bearing fruit, 18, 222.

— in the Carboniferous formation of
the U. S., 17, 315.

Corner-stones, decay of articles de-
posited in, 5, 323, 325. 350.
Corona, high voltage, in air, 50,

374-
Coronas of cloudy condensation, elec-
tron method of standardizing, 48,

177-

Corpus luteum, 4, 305.

Correlations of cosmical and molec-
ular force, 12, 392.

— of planetary mass, 13, 239.

— stellar and planetary, 12, 518.
Corundum, its alterations and asso-
ciated minerals, 13, 361.

— and wavellite near Allentowii, Pa.,
20, 230.

Coryphodon, brain of, 16, 616.
Cosalite, alaskalite and beegerite. 22,

211.
Cosmogony, new, 50, 261.

— of Laplace, 18, 324.

Cosmography, Munsters' 18, 443.

Cost of living in 12th century, 50,
496.

Costa Rica, Indian tribes and lan-
guages of, 14, 483-

Cotylosauria, 34, 436; 35, 122.

Coues, Elliott, a description of the
Lewis and Clark mss., 31, 17.

Crandall, Roderic, geology of the
San Francisco Peninsula, 46, 3.

Crane, T. F.. mediseval sermon books
and stories, 21, 49.

Cranium, ftietal, measurements of, 3,
12;.

Crawford, Earl of, ms. history in
the library of the American Phil-
osophical Society, 42, 397.

Creation, biblical account of the, 18,
316.

Creative Fiat, planetary illustrations
of the, 14, 609.

Cremastochilus of the United States,
revision of the, 18, 382.

Cremation among the Digger Indians,
14, 4^4-

• Pah-Ute, 14, 297.

Creodonta, genera of, 19, y6.

Cresson, Charles M., bituminous ma-
terial from Pulaski Co., Va., 17,

215-

— • — 'effect of magnetic and galvanic
forces upon the strength of, and
destruction of iron and steel struc-
tures, 14, 603.

'examination of an exploded

locomotive boiler, 14, 264.

Rocky Mountain coals, 14, 358.

Cresson, John C, aurora, February 7,
20, 21, 1866, 10, 206.

, — and earthquake, recent, 11,

522.

copper coin, 10, 270.

diamagnetism, 10, 199.

— — explosions in mines, 10, 338.

fall of a gasholder. 5, 164.

fish in coal mines. 10, 168.

four rainbows, 10, 148, 149.

22

PROCEEDINGS, VOLS. 1-50

CRESSON-DARL

Cresson, John C. (continvied).

high barometer, February loth

and nth, 1867, 10, 329.

lunar rings, July 27, 1866, 10,

270.

meteors, 10, 335. 342.

— • — -obituary notice of. 17, 149.

— ■ — odor and temperature in plants,
10, 354.

onion disease. 10, 168.

remarkable electrical phenom-
ena. 7. 385-

•storm, 7, 176, 292; 9, 59.

tornado. ]\Iay 11, 1865. 10, 108.

transmission of sound through

iron pipes. 5, 118.

Cretaceous and lower tertiary section
in south central Montana, 41, 207.

Crinoid, with movable spines, 21, 81.

Crookes tube, properties of the field
surrounding a, 42, 96.

Crotch. G. R.. arrangement of the
families of Coleoptera, 13, 75.

Crummel, Alex., African dialects, 9,
3-

Crural processes in genus Atrypa,
17, 337-

Crustacean, large, from the Cats-
kill group of Pennsylvania, 21, 236.

Crystalline compounds, in higher
plants. 25, 124.

— rocks of eastern Pennsylvania,
relations of the, to the silurian
limestones and the Hudson River
age of Hydromice schists, 18, 435

Crystallographic properties, 42, 237
— -study of the hemoglobins, 47, 298
Crystallography in sculpture. 17, 258,
Crystals, artificial production of, 42
219.

— inclusion and occlusion of solvent
in, 42, 2S.

Cuba, geology of, 3, I54; 25, 123.
Cuckoos, osteology of, 40, 4.
Culture, scientific, tendencies of. 18,
569.

Cumberland coal l^asin, 11, 9; 19,
III.

Cumulus cloud, formation of, from
the action of fire, 2, 116.

Curculionidae of the United States,
13, A07-

Currency, metallic, specimens of, 5,
198.

Currents, relation of auroras to grav-
itating, 12, 121.

— resemblance of atmospheric, mag-
netic and oceanic, 12, 68.

Curtis steam turbine, 42, 68.

Curves, orthic ; or, algebraic curves
which satisfy Laplace's equation
in two dimensions, 43, 294.

Curwen, John, obituary notice of
Thomas S. Kirkbride, 22, 217.

Gushing, Frank Hamilton, explora-
tion of ancient key dwellers' re-
mains, on the gulf coast of
Florida, 35, 329.

Shamanism, 36, 183.

Cyanosis neonatorum, 3, 174.

Cyclovolute, magic, 4, 125.

Cylinders,' linear resistance between
parallel conducting, 48, 142.

Da Costa. J. M., obituary notice of

Samuel D. Gross, 22, 78.
Daguerreotypes. 2, 144, 150.

— of the ]Moon, 5, 208.

Dallas, \V. L., pressure and rainfall
conditions of the trades-monsoon
area, 44. I59-

Dana, Charles E., notes on cannon,
fourteenth and fifteenth centuries,
50, 147.

Daniel's comet, photographic obser-
vations of. 49, 3.

Danish explorations in Greenland,
22, 280.

Darlington, \\"illiam, obituary notice
of, 9. 330.

, of William H. DiUing-

ham, 6, 91.

23

DARWIN-DEPOT

GENERAL INDEX

Darwin, Charles R., influence of, on

mental and moral sciences, 48, xxv.

. on the natural sciences,

48, XV.

ol)ituary notice of, 20, 235.

-personal reminiscences of, and

of the reception of the " Origin
of Species," 48, iii.

the world's debt to, 48, xxxviii.

Datamcs Magna, description of, 25,
107.

Davenport, Charles B., determination
of dominance in Alendelian inherit-
ance, 47, 5Q.

— -^new views about reversion, 49,
291.

Davenport, G. E., tables of the dis-
tribution of ferns of the United
States, 20, 605.

Davidson, George, longitude and ve-
locity of the electric current be-
tween Cambridge and San Fran-
cisco, II, 91.

new transit level, 10, 288.

— • — -San Francisco earthquake of
1906, 45, 164, 178.

• — • — -transit of venus at Nagasaki,

14, 423-
Davidson, Mrs., transit of venus, 14,

423-

Davies, John Vipond, tunnel con-
struction of the Hudson and Man-
hattan Railroad Company, 49, 164.

Davis, Isaac R., obituary notice of,
6, 299.

Davis, Wm. Morris, Antarctic geol
ogy and Polar climates, 49, 200.

conversion of chlorine into liy-

drochloric acid, as observed in the
deposition of gold from its solu-
tions l)y charcoal, 21, 102.

systematic geography, 41, 235.

was Lewis Evans or Benjamin

Franklin the first to recognize that
our northeast storms come from
the southwest, 45. 129.

Dawson, James W., Cape Breton
coal beds, 9, 165, 20S.

Day, David T., petroleum, 36, 112.

Day, Frank M., microscopic exami-
nation of timber, with regard to its
strength, 21, :^,-^3.

Day, nei)ular origin of the terrestrial,
18, 3X0.

Day, William C, asphalt, production
of an, resembling Gilsonite by
the distillation of a mixture of
fish and wood, 37, 171.

Death penalty, by electricity, 47, .39-

Dcbituminization, violation of the
law of, 12, 125.

Decapods, geographical distribution
of freshwater, and its bearing
upon ancient geography, 41, 267.

Decimals, pure circulating, 40, 148.

Declaration of Independence, contri-
bution to the bibliography of the,
39, fx)-

fac-simile of, 37, 81.

note on the Jeft'erson manu-
script draught of the, in the library
of the American Philosophical
Society, 37, 88.

notes on the various copies of,

in Jefferson's handwriting, 29, 134.

Deer, cjilculus found in a, analysis
of a, 18, 213.

Defla.gration, galvanic, i, 253.

Delaware tale, a modern, 41, 20.

—-Water Gap, soundings at the, 9,

45 f-
Delmar, Alex., resources, productions

and social condition of Egypt, 14,

2 32.

, — ■ — — — of Spain, 14, 301.

Delticholum gibbosum, 26, 529.
Density and Polarity, sethereal, 12,

407.
— relation of temperature to, 10,

261.
Depot of charts and instruments of

the U. S. Navy, 3, 85.

24

PROCEEDINGS, VOLS. 1-50

DERBY-DRAPER

Derby, Orville A., geology of the

lower Amazon, 18, 155.
— ■ — , — of the diamantiferous region

of the province of Parana, Brazil,

18, 24S, 251-

Dermestidre of the United States,

revision of the, 20, 343.
Desor, Edouard. lake dwellings, 9,

413.
obituary notice of, 20, 298, 519.

— — pierres a eceuilles en Europe,

17, 714-

Development, the beginnings of, 14,
622.

Devonian rocks at Palenvillc in the
Catskills, 17, 346.

Dew and hoar frost, 9, 456.

Dew point hygrometer, 2, 249, 252.

Diabase, miocene, of the Santa Cruz
Mountains in San Mateo Co., Cali-
fornia, 43, 16.

Diamagnetism, 10, 199.

Diamantiferous region of Parana,
Brazil, geology of, 18, 248, 251.

Diamond found in Georgia, 4, 211.

— light produced by, 7, 175.
Dibenzy], 18, 345.
Dichlorsalicylic acid, 17, 68.
Dicotylins of the John Day Miocene

of North America, 25, 62.
Didelphis virginiana, 4, ^ly .
Diego de Landa's writings, 24, i.
Dillingham, William H., obituary

notice of, 6, 91.

— • — . of Judge Gaston, 4, 49.

Dimethyl racemic acid, 43, 105.
Dinosauri in Wyoming transition

beds, 12, 4S1.
Dinosaurian Lselaps Incrassatus, skull

of the, 30, 240.
Dinosaurus from Utah Trias, 16, 579.
Dioxyethyl-methylene, 18, 346.
Disk, engraved, found in Guatemala,

19, 191-

Distance, effect of imperceptible
shadows on judgment of, 46, 94.

Dixon, Samuel G., obituary notice of
Isaac Lea, 50, xxxix.

Dock, effects of lightning in deep
mines, 10, 288.

Dodecahedron, relation of the pen-
tagonal, found near Marietta,
Ohio, to Shamanism, 36, 179.

Dolley, Charles S., obituary notice of
John M. Maisch, ZZ', 345-

— • — 'Thyrsus of Dionysos, and the
palm inflorescence of the winged
figures of Assyrian monuments, 31,
109.

Dolomite, analysis of pure, 19, 197.

Dolomitic limestone rocks of Cum-
berland Co., Pa., 18, 114.

Domes, construction of, 10, 379.

Doolittle, Charles L., obituary notice
of Simon Newcomb, 49, iii.

— • — variation of terrestrial latitude.
36, 434-

Doolittle. Eric, orbit of double star
^ 518. 42, 170.

Dopplerite, substance resembling,

20, 112.

Doremus, Charles A., identification
of colored inks by their absorption
spectra, 35, 71.

Double star ^ 518, orbit of, 42, 170.

Douglas, Earle, cretaceous and lower
tertiary section in south central
Montana, 41, 207.

Douglas, James, obituarj' notice of
Thomas Sterry Hunt, Memo-rial
Volume, I, 63.

record of borings in the Sul-
phur Spring Valley, Arizona, and
of agricultural experiments in the
same locality, 40, 161.

Drake, Noah Fields, coal fields of the
Indian Territory. 36, 2^26.

Draper. Henry, discovery of oxj-gen
in the sun by photography, 17, 74.

— — memorial photographs of stellar
spectra, 24, 166.

obituary notice of, 20, 656.

25

DRAPER-DuPONCEAU

GENERAL INDEX

Draper, irienry (continued").

— — photographing the nehula of
Orion. 19, 156.

Draper, John W., decomposition of
carbonic acid and the alkaline car-
bonates by light of the sun. 3, in.

-effects of sunlight, 3, in.

— • — obituary notice of, 20, 22"/.

Drift phenomena of the U. S.. 18,
85.

Dromathcrium and Microconodon,
Triassic mammals, 24, 109.

Du Bois, Patterson, Great Japanese
Embassy of i860, 49, 243.

notes on copies of Declaration

of Independence in Jefferson's
handwriting, 29, 134.

obituary notice of James C.

Booth, 25, 204.

— — priority, a matter of. 34, 67.
Du Bois, William E., aluminum, 6,

141. 148, 172.

assay balances. 9, 226.

Australian gold from ]\It. Alex-
ander, 5, 313.

average health of Philadelphia

in comparison \vith other cities,
9, 26.

Chiriqui images, 7, 162.

— — engraved disk found in Guate-
mala, 19, 191.

Japanese coins and Austrian

money, 8, 264.
Lake Superior silver ore, 6,

155; II, 527.

— ^magnesium and its light, 9, 458.
-metallic currencv, specimens of,

5, 19S.

Mint Cabinet, late additions to,

6, 184.

-natural dissemination of gold.

8, 273.

obituary notice of, 20, 102.

, of Jacob R. Eckfeldt, 12,

547-
Siamese photographs, 10, 201.

Du Bois, William E. (continued).
silver coins from the wreck of

the ■' San Pedro," 4, 200.

, of the Mint, 11, 233.

, — mines of Lake Superior, 11,

5^7-

, — -ore, II, 92.

— - — speciljc gravity apparatus, 6,

193, 201. *"
— • — -supposed coin found in Illinois,

12, 224.

— • — -torques, 5, 202.

Turkish paper money, 6, 154,

214.

Ducatel, Julius T., physical history
of the State of ^Maryland, 3, 158.

Dudley, Charles B.. passenger car
ventilation, 43, 247.

Dudley, Thomas H., is there reci-
procity in trade?. 23, 526.

obituary notice of, 34, 102.

Duges, Alfredo, deux especes nou-
velles des Ophidiens de Mexique,

25, 181.

^Rhinocheilus Antonii, 23, 290.

Dunglison, Robley, obituary notice

of George W. Bethune, 9, 70.
, of John K. Mitchell, 6,

340.

, of George Tucker, 9, 64.

vaccine virus, liability of, to

deterioration, i, 68.

worm in a horse's eye, i, 200.

Dunning's Creek fossil iron ore bed,

13, 136.

DuPonceau, Peter S., Anamitic lan-
guage, I, 235.

and John Hecke welder, corre-
spondence respecting the Indian
languages. Trans. Hist, and Lit.
Conini., I, 357.

Centennial Address, 3, i.

Chinese system of writing.

Trans. Hist, and Literary Com-
mitter, 2, I.

silk culture in India, i, 214.

26

PROCEEDINGS, VOLS. 1-50

DURAND-ELEC

Durand, Elias. Arctic plants, 6, 186.

obituary notice of Frangois

Andre Michaux, 6, 223.

, of Thomas Nuttall, 7, 297.

Dutton, Clarence E., causes of re-
gional elevations and subsidences,
12, 70.

Dwight, Thomas, psoas parvus and
pyramidalis, variation in, 31, 117.

Dykes, trap, in Archaean rocks of
southeastern Pennsylvania, 21, 691.

Dynamic induction Ijy a galvanic cur-
rent, I, 135.

D3'namo-electric machines, circum-
stances influencing efficiency of,
18, 5S

Earth, dimensions of the, 3, 130.

— past history of the, 48, 119.

— physics of the, 47, 157.

— temperature, secular cooling and
contraction of, 46, 191.

— topography as affected by rotation
of the, 13, 190.

Earth's orbit, comparative energy of
action and reaction at the source
of solar radiation and at, 10, 261.

Earthquake at Aix-la-Chapelle. 18,
216.

— of 4th of Januarv, 1843, 2, 258,
267.

— San Francisco, of 1906, 45, 164,
178.

Earthquakes, 3, 64.

— ancient and modern theory of,
46, 191.

— cause of, 45, 274; 48, 235.

— establisment of National bureau
for study of, 48, xii.

— mountain formation, new theory
of, 46, 369.

Echo, experiments to determine the
depth of the sea by the, i, 39.

Eckfeldt. A., aluminum, 6, 141, 148.

— • specific gravity apparatus, 6, 193,
201.

Eckfeldt, Jacob R., obituary notice

of, 12, 547.
Eclipse, solar, of 1836 and 1838. i, 31,

35. 44, 48, 50, 58, 64, 107, 177.
of 1846, 4, 253.

— — of May 26, 1854, 6, 38.

of Aug. 7, 1869, II, 204.

of July 29, 1878, 18, 103.

Eclipses, solar, i, 132, 177; 2, 201;

3, 1B3; 5, 32.

Economies, classification of, 41, 169.

Ectophylla alba, skull and teeth of,
19, 267.

Eddy, Henry T., radiant heat, an ex-
ception to the second law of ther-
modynamics, 20, 334.

Edentata, bones of a fossil animal of
the order, 2, 109.

Edmunds, George F., international
arbitration. 36, 320.

Egypt, resources, productions and so-
cial condition of, 14. 232.

Egyptian character of Hebrew
names, 20, 506.

— element in the names of Hebrew
kings, and its bearing on the his-
tory of the Exodus, 19, 409.

— ethnography, 2, 239; 3, 115.
Egyptology, manual of, 20, i.
Elasmobranch genus Didymodus,

structure of the skull in, 21, ^~2.
Elastic force, unity of, 9, 425.
Elbow joints, false, 30, 285.
Electric and other elastic currents,

mechanical modification of, 9, 355.

— muscular sensibility, measure of,

6, 291.

Electrical phenomena, remarkable,

7, 385.

— progress since 1743, 32, 104.
Electricity and matter, modern theory

of, 50, 321.

— as a motor, 37, 8.

— disruptive discharges of, through
flames. 50, 397.

— death penalty by, 47. 39-

27

ELEC-ESPY

GENERAL INDEX

Electricity (continued).

— experiments on, 4, 208.

— from steam, i, 320; 2, 3.

— transmission of energy by, 38,

49-
Electro- analysis, use of the rotating
anode and mercury cathode in,

44. 137-
Electro-dynamic induction, i, 54.

315-

Electrolysis, new results in, 46, 341.

Electrolytic estimation of cadmium,
18, 46.

Electromotive force, measurement of,
20, 649.

Electrons, dynamical effects of ag-
gregates of, 50, 347-

— positive and negative, 45, 103.
Elevations, causes of regional, 12,

70.

— list of, in Indiana County, Pa.,

17, 145

Elliptic interference with reflecting
grating, 50, 125.

Emerson, Gouvernenr, causes opera-
tive in changing the proportions of
the sexes, 5, 20.

■ ettects of hot weather upon

infants, 4, 213.

electricity from steam, 2, 3.

excessive mortality of male

children, 4, 212.

— imphee, or African sugar-cane, 9,
141.

importance of phosphoric acid

in agriculture, 8, 378.

light produced by the diamond

by friction, 7, 175.

lunar influence on wet and dry

\veather, 12, 17.

obituary notice of, 29, 60.

-part taken Ijy the American

Philosophical Society in establish-
ing stations for meteorological ob-
servations, II, 516.

sorghum culture, 9, 116.

Emerson, Ralph Waldo, obituary
notice of, 20, 498.

Emmett, W. L. R., Curtis steam tur-
bine, 42, 68.

Emmons, S. F., geology of Mont-
gomery Co., Md., 5, 85.

Emys, taxonomy of the genus, 30,
40, 245

Encke's comet, 2, 186.

Energies, luminous and cosmical, re-
lation of chemical affinity to, 19,
21.

Energy as a factor in organic evolu-
tion, 31, 192.

— ■ transmission of, by electricity,
38, 49-

English Channel, railway under,

17. M-

— history, observations on Gildas and
the uncertainties of early, 25,

13-'.

— orthography and pronunciation,
8, 285, 9, 239.

Ennis, Jacob, on the Nebular Hy-
pothesis, 9, 441 ; 10, 150.

Eocene carnivorous animals, 20, 226.

— • gigantic mammals of the Amer-
ican, 13, 255.

Equations, algebraic, solution of, in
infinite series, 47, in.

— linear differential, on the solution
of. 50, 274.

— new application of JNIacLaurin's
Series in the solution of, 42, 85.

— ■ reversion of series and its applica-
tion to the solution of numerical
21, 91.

Equivalents, comparison of mechan-
ical. II, 313-

Erman's orbits of the periodical
meteors, 2, 21.

Ertel meridian circle, 4, 113.

Espy, James P., law of cooling at-
mospheric air. 3, 155.

— — ■ nepheloscope, 2, 128.
Espy's theory, 2, 147.

28

PROCEEDINGS, VOLS. 1-50

ETHEO-FEET

Etheostomine percli from Tennessee
and North Carolina, 11, 261.

Ether, deterioration of, by age, 9,
171.

— drift, 49. 52.

— influence of, on solar system, 9,

384.

— perchloric, i, 261.

Ethereal liquid, new, 2, 142, 161.
Ethics of Solomon, 33, 310.
Ethnography, protohistoric, of West-
ern Asia, 34, 71.
Ethnology, observations on, 4, 358.

— of British Columbia, 24, 422.
Ethyl, neutral sulphate of oxide of,

5, .35-
Etruscan and Libyan names, 28, 39.
Etruscans, ethnologic affinities of the

ancient, 26, 506.
Etrusco-Libyan elements in the song

of the Arval Brethren, 30, 317.
Etymologies, Hebrew, from the

Egyptian axx, 29, 17.
Etymology, Greco-Egyptian, of

la/cxos, 19, no.

— probabilities in, 10, 345.
Eucalyptus in Algeria and Tunisia,

from an hygienic and climatolog-
ical point of view, 35, 39.

Euphoridse of United States, 18, 397.

Eurypterids from coal shales, 21,

343-
Eve, ancient protest against curse

on, 50, 504.
Evolution, cosmical, 14, 159: 49,

207.
— , — factors of, 35, in.

— organic, energy as a factor in, 31,
192.

— , — from a botanical standpoint, 35,
88, no, n3.

— . — from the embryological stand-
point, 35, 78.

— philosophy of, 26, 495.

Ewell, [Marshall D., modern microm-
eters, 46, 187.

E.xfoliation of Gettysburg rocks, 14,

295-
Exner, Franz F., atomic weight of

tungsten, 43, 123.
Explosions in mines, 10, 338.
Eye, catoptric examination of the,

I, 97-

— horse's, worm in a, i, 200.

— ocular muscles, and lachrymal
glands of the shrew mole, 28, 16.

Facial nerve in the domestic cat, 24,
8.

Family as an element of govern-
ment, 9, 295.

Faraday's desideratum, accomplish-
ment of, 10, III.

Farr, Marcus S., osteology of the
White River horses, 35, 147.

Fatalism and scientific naturalism,
41. i45-

Faults, Perry County, 21, 218.

Fauna, extinct, batrachian, of the
Linton (O.) Carboniferous, 12,
^77-

— fresh water, destruction of, in
western Pennsylvania, 48, 90.

— • mammalian, from the Deep River
Beds of Montana, 31, 251.

— marsupial of the Santa Cruz
Beds, 44, 73.

— miocene, of Oregon, 18, 63, 370.

— molluscan, of the Patagonian Ter-
tiary, 41, 132.

— of the miocene and eocene periods
of the United States, 11, 285.

— of the Permian formation of
Texas and Indian Territorv, 22,
28.

— of the Puerco eocene, 20, 461,
545-

Feet, structure of the. in the extinct
Artiodactyla of North America,
22, 21.

— thoracic, in a Carboniferous Phyl-
locaridon, 23, 380.

29

FELDSPAR-FOOT

GENERAL INDEX

Feldspar, analysis of, 2, 53.

— bed in Laurentian gneiss, 29, 49.
Female sex, the morphological supe-
riority of the, 43, 365.

Fennell, C. A. M., pure circulating

decimals, 40, 148.
Ferns, distribution of, of the U. S..

20, 605.
Field, Henry W., obituary notice of

John F. W. Herschel, 12, 217.
Field, R. P., span of life, 36, 420.
Filipino; his customs and character,

44, 6.
Fireballs, meteoric, in the United

States, 16, 590.

— note on the possible existence of,
and meteorites in the stream of
bielids, 24, 436.

Fire-damp explosions in Pennsyl-
vania anthracite mines, 19, 405.

— indicator, on Kintzes', 21, 28^.
Fish in coal mines, 10, 168.
Fish-plate from upper Chemung Beds

of northern Pennsylvania, 20, 664.
Fisheries, American-British Atlantic,

48, 319-
Fishes, Alaskan, 13, 24.

— cretaceous of tlie L'nitcd States,
II, 240.

— fossil. II, 316, 431.

from Kansas cretaceous. 12.

327-
from the Loess of the ^Nlissis-

sippi River, 10, 256.
— ■ — from the upper coal measures

of Nebraska, 11, 431.
— ■ Green River, Wyoming Territory,

II, 370, 380.

— Idaho fresh water tertiarv, 11,
538.

— -North Carolina fresh water, 11,
44-'. 44.^-

— obtained by the naturalist expedi-
tion in Rio Grande do Sul, 33, 84.

— Permian Amazon, 17, 673.

— Utah, 14, 129.

Fissipedia. systematic relations of

carnivorous. 20, 471.
Flaccus, M. v.. epitaph of. 25, 55.
Flax culture, 9, 26.
Floods, effect of, upon vegetation,

50, 118.
Flora, American coal. 9, 198; 16,

397-

— of northern Yucatan. 29, 137.

— -of Pennsylvania, relic of the na-
tive, surviving in Perry County,
21, 226.

Moras, temperate and Alpine, of the
giant volcanoes of Mexico, 30, 4.

— -Tertiary of the Atlantic and Gulf
Coastal Plain, 50, 301.

Flow of water through an opening,
16, 3'o; 17, 124.

I'luid stream, elimination of velocity,
effects in measuring pressures in,

45, 77-

I'luids in motion, i, 191.

— -microscopic examination of. 13,
180.

Fly, Hessian, i, 318; 2, 42.

Fly-wheel, deviating forces of a, 17,
126.

F(etal cranimn measurements. 3,
127.

Foggy air not a conductor of elec-
tricity, 2, 180.

Folk-lore of Philadelphia and its
vicinity, 25, 139; 30, 246.

— fairy, of Spencer and Shakespeare.

16, 335.

Folk-medicine of the Pennsylvania

Germans. 26, 329.
Fontaine. William. Saltville Valley

(Va.) fault, 19, 349.
Foot of Toxodon, posterior, 19, 402.
Footmark in hieroglyphic script, 12,

193-

Footprint, ancient human, from Nic-
aragua, 24, 437.

Foot-prints, Batrachian, in anthracite,

17, 716.

30

PROCEEDINGS, VOLS. 1-50 FOOT-FRANKLIN

Foot-prints (continued).

— -Reptilian, at Sharp Mountain. Pa.,

5, 91.
Force, central, some fundamental

propositions of, 16, 298; 17, 98.

— cosmical and molecular, correla-
tions of, 12, 392.

— magnetic, gravitating and lumi-
nous, 14, 607.

— origin of attractive, 14, iii.

— which controls stellar systems as
well as molecular motions, 10, 97.

Forces, elastic and gravitating, 13,
142.

— magnetic and galvanic effect of,
on iron structures, 14, 603.

Forestry, on the growth of the, idea

in Penns3lvania, 32, 332.
Forests, burned, 50, 224.

— of Pennsylvania, 33, 114.
Forgery, new methods for the detec-
tion of, 33, 251.

Fork, French normal, exactitude of,

17, So.
Formates, electrolysis of metallic,

29, 103.
Forscher, die, 32, 345.
Forshes", C. G., great mound near

Washington, Adams Co., ^liss., i,

305.

— — meteors, 2, 67.

Fort William Henr}-, journal kept

during the siege of, 37, 143.
Fossil forms, commingling of, 20,

477-

in quartzose rocks, of the lower

Susquehanna, 18, 277.

— ore bed at Dunning's Creek, Pa.,
II, 156.

Fossile, cours de botanique, by Prof.

M. B. Renault. 19, 287.
Fossils from Colorado, New Mexico

and California, 11, 425.

— from West-India Caves, 11, 608.

— Laurentian. from Essex Co., N. Y.,
II, 237.

Fossils (continued).

— Marine, from the coal measures
of Arkansas, 35, 213.

— ■ Miocene, in San Domingo, 12,
571. 572.

— Missouri. 2, 183.

— of the Rocky [Mountains found in
1870-72, 12, 578.

Foulke, William Parker, obituary no-
tice of, 10, 481.

■ — • — -Pharmacopoeia Londinensis Col-
legarum, 9, 224.

Fowl's egg, mechanical genesis of
the, 31, 203.

Fowler, Henry W., of Coregonus
nelsonii Bean, 43, 451.

Fraley, Frederick, address at centen-
nial of incorporation of the Amer-
ican I hilosophical Society, 18, 513.

. — at the centennial of the

American Philosophical Society's
occupation of its Hall, 27, 4.

■ , — at the centennial of the death

of Benjamin Franklin, 28, 173.

addresses at the One Hundred

and Fiftieth Anniversary of the
Foundation of the American Phil-
osophical Socity, 32, 7. 17, 159.

— - — Franklin's association with the
Society, 28, 173.

— - — note on Pennsylvania Bi-Cen--
tennial, 20, 497.

obituary notice of, 40, i.

. of John C. Cresson, ij^

149.

, of William Roberts, 20,

199.

Francke. Kuno, mediseval German
sculpture in the Germanic Museum
of Harvard University, 47, 635.

Franklin, Benjamin, as a meteorolo-
gist, 45, 117-

-association with the Society,

28, 173-

Bagatelles, 40, 87.

biography of, 28, 166.

31

FRANKLIN-FRENCH

GENERAL INDEX

Franklin, Benjamin (continued).

Centennial of Death of, 28, 162.

diplomatic services of, 28, 209.

extracts from unpublished let-
ters of, 3, 168.

letter from, to Dr. Kinnersley,

4, 279.

letters from, originals of which

are in Leipzig, 34, 482.

— ■ — literary labors of, 28, 177.

papers in the American Philo-
sophical Society, 42, 165.

• -Printer, Patriot and Philoso-
pher, 32, 42.

scientific work of, 28, igg.

Franklin Listitute, part taken by the,
in establishing stations for meteoro-
logical observations, 11, 516.

Franklinite ore, 9, 88.

Frazer. J. F., eclipse of the Sun, ALay
26, 1854, 6, 38.

, obituary notice of, 13, 183.

, of Henry Reed, 6, 87.

tornado of August 5, 1843, 4,

12.

and John C. Cresson, trans-
mission of sound through iron
pipes, 5, 118.

Frazer, Persifor, color of the Moon,

14, 155-
-composite photography applied

to handwriting, 23, 433.
convenient device to be applied

to the hand compass, 22, 216.
■ crystallography in sculpture, 17,

258.
Cuba, geology of eastern, 25,

123.

exfoliation of rocks near Gettys-
burg, 14, 295.

fifteenth problem, 18, 505.

forgery, new methods for the

detection of, 33, 251.

fossil forms in quartzose rocks,

of the lower Susquehanna, 18, 277.

horizon of the South Valley Hill

Rocks in Pennsylvania, 20, 510.

Frazer, Persifor (continued).

improvements in the hypsomet-

rical aneroid, 20, 604.

International Congress of Geol-
ogists, Berlin, 1885, 23, 259.

joint signature marks, evidences

of the action of two hands in,
34, 473-

— — limonites of York and Adams
Counties, 14, 364.

lithologie du fond des mers of

M. Delesse, 16, 238.

— - — magnetic declination, theory of,
16, 642.

Mesozoic ores, 16, 651.

microscopical observations of

the phonograph record, 17, 531.

, — sections of traps on the Mes-
ozoic red sandstone of Pa. and
Connecticut, 14, 430, 431.

mirror for opaque objects for

the projecting microscope, 18, 503.

f)bituary notice of Robert Frazer,

18, 233-

, of Edward Yorke Ma-

cauley, 34» 364-

— — Peach Bottom slates, 18, 366.
— ■ — -remarks on Prime's paper, 17,

255-
— - — spectroscopic examination of the

aurora, April 10, 1872, 12, 579.
■ tal)les for interconversion of

inetric and English units, 17, 536.
— - — telephonic overtones, 18, 39.
trap at Williamson's Point, 18,

96.
, — dykes in Archaean rocks of

southeastern Pennsylvania, 21, 691.
— ■ — -traps of the Mesozoic sandstone

in York and Adams Counties, Pa.,

14, 402.
— - — ^ York County, Pennsylvania,

geology of, 23, 391.
Frazer, Robert, obituary notice of,

18, 233.
Frencli members of the American

Philosophical Society, 46, 87.

32

PROCEEDINGS, VOLS. 1-50 FRIENDS-GENTH

Friends who have passed away, 18,

541.
Frieze, Henry Simmons, obituary

notice of, 28, 59.
Fuegian languages, notes on, 30, 83,

249.
Fuel from coal dust, 10, 290.
Fullerton, George Stuart, influence

of Df.rwin on the mental and

moral sciences, 48, 25.
Fulton, J., Somerset County, Pa.,

coal Ijeds, 14, 157.
Funeral customs of Ireland. 25, 243.
Fungicide, dilute sulphuric acid as a,

45, 157-
Fungus in Darlington shales at Can-

nelton. Pa., 17, 173.
Furness, Horace Howard, obituary

notice of Henry Charles Lea, 50,

xxix.
Furness, William H., obituary notice

of. Memorial Volume, i, 9.
Furness, William Henry, 3rd,

glimpses of Borneo, 35, 309.
Fusible metal, 2, 42.

Gabb, William ISL. Indian tribes and
languages of Costa Rica, 14, 483.

Miocene fossils in San Dom-
ingo, 12, 571, 572.

Mollusca of the cretaceous for-
mation, 8, 57.

Gales, vortical, of January, 1864, 9,
361.

Galle's first comet, i, 301.

■ — -second comet, i, 216, 275.

Galvanic deflagrator, i, 253.

— influence through wire coil, i, 199.

Galvanometer, new vertical lantern,
14, 440.

Gamuts of sound and light, 13, 149.

Garman, Samuel P>., Reptiles and Ba-
trachians of Grand Cayman, 24,
273-

-West Indian reptiles, 24, 27S.

Garrett, Philip C. obituary notice of
Pliny E. Chase, 24, 287.

Gas, action of, from As^.Oa and
HNO3 upon m-oxybenzoic acid,
25, 194-

— analysis, 17, 473, /22, yzT,.

— burner, dispersion of heat gener-
ated by, 17, 309.

— 'generator, Schintz's. 10, 9.

— natural, genesis of, and petroleum,
36, 116.

from certain wells in western

Pennsylvania, 16, 206. 585.
— -well at Alurrayville, Pa., 18, 207.

— wells on the Kanawha, 4, 366.
Gases, calculation of results in analy-
sis of, 17, 473-

— spectra of, at high temperature,
41. 138.

Gasholder, fall of a, 5, 164.
Gaston, William, obituary notice of.

4, 49-

Gatschet, Albert S., Aruba language

and Papiamento jargon, 22, 299.
Beothuk Indians, 22, 408; 23,

411 ; 28, I.
■ Isleta Indians, mythic tale of

the, 29, 208.
Timucua language, 16, 626; 17,

490; 18, 465.

— — -Tonkawa language, 16, 318.
Genesis XI, 1-9 as a poetic frag-
ment, 35, 305-

Genth, F. A., contributions to min-
eralogy, 13, 361; 20, 3S1 ; 23, 30;
24, 23.

-corundum, its alterations and

associated minerals, 13, 361.

gold sand from Philadelphia,

II, 439-

herderite, 21, 694.

iron ores and limestone from

Spruce Creek, &c., 14, 84.

— - — native lead in gold from Mon-
tana, II, 443.

obituary notice of. 40, 10.

-pyrophyllite from Schuylkill

Co., Pa., 18, 279.

reply to T. Sterry Hunt, 14, 216.

33

GENTH-GOLD

GENERAL INDEX

Genth, F. A. (continued).

San Domingo Rhodium gold,

II, J3g.

' •tclli-,rium and bismuth minerals,

14, -^^3-

, — and vanadium minerals. 17,

113-

and Gerhard von Rath, vana-
dates and iodyrite from Lake Val-
ley, Sierra County N. \l., 22, 363.

Geography, contributions to, 6, 347,
352; 7, 25, 123.

— systematic, 41, 235.
Geological notes, 3, iSi ; 20, 529.

— reconnaissance of Bland, Giles,
Wythe and portions of Pulaski
and Montgomery Counties of Vir-
ginia, 24, 61.

— section at St. r^Iary's, Elk County,
Pa., 19, 337-

— structure of Tazewell, Russell,
Wise, S'myth and Washington
Counties, Virginia, 22, 114.

Geological survey of Pennsylvania,

16, 55; 20, 537; 22, 86.
Geology, Cope's contributions to,

Memorial Volume, i, 303.

— evolution and the outlook of seis-
mic, 48, 259.

— statistical method in chemical, 45,
14-

Gibbs, Josiah Willard, obituary notice
of, 42, xvi.

Gildas, observations on, and the un-
certainties of early English history,
25, 132.

Giles Co., Va., geological reconnais-
sance of, 24, 61.

Gill, Theodore, Cope's herpetological
and ichthyological contributions,
Memorial Volume, i, 274.

notes on StromateidcC, 21, 664.

Gilliss, J M., depot of charts and in-
struments of U. S. Navy, 3, 85.

Observatorv at Washington, 3,

85.

Gilman, Daniel C, alliance of the
universities and the learned socie-
ties, 18, 536.

■ obituary notice of, 48, Ixii.

Gilpin, Henry D., biographical sketch
of Edward Livington, 3, 92; Trans.
Hist, and Lit. Comm., 3, 65.

obituary notice of, 7, 347.

Gilpin, Thomas, lunar influence upon
weather. 5, 117.

— ■ — -obituary notice of, 6, 13.

position of organic remains as

connected with a former tropical
region of the earth, 4, 2J.

Ginley, W., crural processes in genus
Atrypa, 17, 2,37-

Glacial action along the Kiltatinny,
Carbon, Northampton, and ]Monroe
Counties, Pa., 14, 620.

— deposits in West Philadelphia, 14,
633.

— -drift of Northampton Co., Pa.,
18, 84.

— epochs, 16, 241.

Glaciation of parts of Wyoming and
Lackawanna Valleys, 23, T,7,y.

Glaisher, James, obituary notice of,
42, II.

Glosso-pharyngeal nerve, in the cat,
25, 89.

Goddard, Martha Freeman, Libellu-
lidcT, on the second abdominal seg-
ment in a few, 35, 205.

Goddard, Paul Beck, invisible pho-
tographic rays, 3, 179.

Gods in the Kiche myths, names of
the, 19, 613.

Gold and silver, varying ratio be-
tween, 34, 49.

— -Australian, from ]Mt. Alexander,
5, 3^3-

— extracting machinery, 10, 29.

— from Montana, native lead in, 11,
443-

— in Pennsylvania, 5, 274.

34

PROCEEDINGS, VOLS. 1-50

GOLD-GROSS

Gold (continued).

— mines of California, effect of,
upon the value of the precious
metais. 5, 148.

— -natural dissemination of, 8, 273.

— San Domingo Rhodium, 11, 439.

— sand from Philadelphia, 11, 439.
Goodale, George Lincoln, influence

of Darwin on the natural sciences.

48, 15.

Goode. G. Brown. literary labors of
Benjamin Franklin, 28, 177.

Goodspeed, Arthur W.. properties of
the held surrounding a Crookes
tube, 42, 96.

Rontgen ray, 35, 17.

Goodwin, Daniel R., obituary notice
of, 28, 227.

. of Ed. Hitchcock. 9, 443.

, of Samuel Vaughan Mer-
rick. II, 584.

Goodwin. Joseph H., electrolytic cal-
cium, 43, 381.

Gortyna and allied genera. 39, 346.

Gowen. Franklin B.. obituary notice
of. 28, 61.

Gradients, computation of the effect
of. 12, 9.

Graff. Frederick, obituary notice of.
28, 104.

, of Strickland Kneass, 21,

451-

Graham. James D.. contributions to
geography, 6, 347, 352: 7, 25. 123.

earthquake, 2, 259.

— - — electrical telegraphic determina-
tion of longitudes, 6, 312.

-lunar tidal wave in Lake Michi-
gan, 7, 378.

-magnetic dip, 4, 205.

-northeast boundary, 4, 53.

reflectors. 2, 260.

Gramophone. 24, 420.

— and telephone records, possible
methods for preparation of, 25, 144.

Grapeville gas wells, 29, 11.

Grating, elliptical interference with
reflecting, 50, 125.

Gravels, auriferous, in North Caro-
lina, 19, 477.

Graveyard, ^^lerovingian, 10, 3.

Gravitating waves, 14, 344.

Gravitation, 18, 41.

Gravity, correlation of. with the ver-
tical deflection of needle, 10, iii.

— cosmical relations of light to. 11,
103.

— determination of, by means of
pendulum apparatus, 32, 84.

— relations of magnetic declination
to. 10, 97, III.

— • and density, relations of tempera-
ture to, 10, 261.

Gray. Asa, early botanists of the So-
ciety. 18, 535.

Green. Samuel A., Benjamin Frank-
lin, printer, patriot and philosopher,
32, 4-2-

Green, William H., action of hydro-
chloric acid and chlorine on aceto-
benzoic anhydrate. 19, 13.

— — dibenzyl, 18, 345.

— • — dioxyethyl-methylene, 18, 346.

saligenin, synthesis of. 18, 451.

Greene, General Nathanael, calendar
of correspondence of, 39, 154.

Greenland, Danish explorations in,
22, 280.

di Gregorio, ]vlarchese Antonio,
names of animals and plants erron-
eously paired in synonymy, 42, 263.

Gregory. Henry D., obituary notice
of, Memorial Volume, i, 123.

Gresham, law of, 47, 18.

Grit, millstone, 9, 197.

— Schoharie, equivalent of, in middle
Pennsylvania, 20, 534.

Gross. Samuel D., obituarj- notice of,

22, 7?,.
, of Charles Wilkins Short,

10, 171.

GROTE-HAMMOND

GENERAL IXDEX

Grote, A. Radcliffe, Apatela, 34,

388.
butterriies, genealogical trees of,

38, 147.
— • — Creation, philosophy of the l->il)-

lical account of the, 18, 316.
Gortyna and allied genera, 39,

346.
Hypenoid IMolhs and allied

groups, 34, 416.
North American Noctuida?, 21,

134-

, Platypterices, Attaci. Hem-

ileucini, etc., 14, 256.

Pierids, descent of the, 39, 4.

results obtained from a search

for the type of Noctua Linn., and
conclusions as to types of Hueb-
nerian noctuid genera represented
in the North American fauna, 41,

4-
specializations of the Lepidop-

terous wing; Parnassi-Papilioni-

dse, 38, 7, 25.
, Pieri-Nymphalidse. 37,

17-

Telea polyphemus, specialized

cocoon of, 41, 401.

Groups generated by two operators
each of which transforms the
square of the other into a power
of itself, 49, 238.

— -of orders two and four. 46, 146.

Guano, Colombian, 6, 189.

Guetares of Costa Rica, ethnic affin-
ities of the, 36, 496.

Gum-elastic goods, manufacture of,
4, 221.

Gun, great Pittsburg, 9, 454.

— cotton, detonation of, 48, 69.

Gundungurra language, 40, 140.

Gurtzlaff, Chinese system of \vriting,
I, 120.

Haehl, H. L. and Ralph Arnold. :\Ii-
ocene diabase of the Santa Cruz
Mountains, 43, 16.

I hemolysis and bacteriolysis, influ-
ence of alcoholic intoxication upon,
41, 140.

Hagen, John G., inclination of the
apparent to true horizon, 20, 206.

— ■ — reversion of series and its appli-
cation to the solution of numerical
equations, 21, 93.

Hail stones, crystal studded, 26, 529.

— storm, 'SIrx 8, 1870, 11, 438.

Llaldeman, S. S.. beads from Indian
graves, 11, 369.

• Longicorna of the United

States, 4, 371.

obituary notice of, 19, 109, 279.

ocular phenomena, 4, 239.

— • — optical phenomenon, s, 16.

phonology of Wyandots. 4, 268.

Hale. Horatio. Intelo tribe and lan-
guage. 21, I.

Hall, Charles E., glacial action along
the Kittatinny mountain, 14, 620.

— ■ — . — deposits in West Phi'adel-
phia, 14, 633.

Hall, C. E. pakeontology. contribu-
tions to, 16, 621.

— ■ — Pennsylvania Geological Survey.
16, 35

— • — relations of the crystalline rocks
of eastern Pennsylvania to the
Silurian limestones and the Llud-
son River age of the Hydromice
schists, 18, 435.

Hall, James, Spirifera of Upper Hel-
derberg. 10, 246.

taconic system of Dr. Emmons.

9, 5

Hall, Roy D. and Edgar E. Smith.
observations on columbium. 44,
177.

Hamites and Semites in the tenth
chapter of Genesis, 43, 173.

Hammer, antique stone, 9, 401.

Hammond, William A., friends who
have passed away, 18, 541.

obituary notice of John W.

Draper, 20, 227.

36

PROCEEDINGS, VOLS. 1-50

HANCOCK-HAST ^

Hancock. Joseph L., Datames )*Iagna,
25, 107.

Hand compass, convenient device to
be applied to the, 22, 216.

Handwriting, composite photography
applied to, 23, 433.

Hanxwell, John, catalogne of the spe-
cies of Batrachians and Reptiles
contained in a collection made at
Pebas, Upper Amazon, 23, 94.

Harbor entrances, physical phenom-
ena of, 25, 19.

Harden, John W., map of anthracite
collieries, 13, 155.

obituary notice of, 18, 422.

Hare, Clark, perdelonic ether, i, 261.

Hare, Robert, amphide salts, 2, 219.

— ^ cloud levels, 2, 187, 190.
extrication of barium, stron-
tium and calcium, i, 130.

-foggy air not a conductor of

electricity, 2, 180.

galvanic deflagrator, i, 253.

, — influence through wire coil,

I, 199.
— • — -iridium, fusiliility of, 2, 182,

is-.

— ■ — metallic calcium, i, 83, 100.

new ethereal liquid, 2, 142, 161.

platinum, 2, 196.

potassium, globular, i, 166.

radiant heat, application of, to

glass. I, 159.

rarefaction, &c., of air, i, 2t,/.

■ rock blasting by galvanic igni-
tion, I, 99.

— — -roseate tint imparted to light of
carburetted h\-drogen, 4, 114.

silicon, new method of procur-
ing, I, 175.

steam, nascent, non-electric, 2,

160.

strictures on Redfield, 2, 141,

--5-

-tornadoes, electrical origin of,

I, 122.

Harkness. William, obituary notice

of. 42, xii.
Harlan. Richard, bones of a fossil

animal of order Edentata, 2, 109.
Harmonies, cosmical and molecular,

13, 237.

— crucial, 18, 34.

Harris, Robert P., Buceros Scutatos,
9, 86.

-California borax, 9, 450.

Harris Museum in Alexandria, an-
tiquities in, 10, 561.

Harrison, Joseph Jr., obituary notice
of, 14, 347-

Harshberger, John \V., comparative
leaf structure of the sand dune
plants of Bermuda. 47. 97-

, of the strand plants of

New Jersey, 48, 72.

— — -grass-killing slime mould. 45,

-271-

— — hygrometric investigation of
influence of sea water on distribu-
tion of salt marsh and estuarine
plants, 50, 457.

taxonomic charts of the ^lon-

ocotyledons and the Dicotyledons.
46, 3U-

Hart, John S., fairy folk lore of
Spencer and Shakespeare, 16, 335.

obituary notice of John Sander-
son, 4, 62.

Hartshorne, Henry, disputed facts in
physiological optics. 16, 218.

— — obituary notice of. 39, i.

. of J. E. Rhoades, 34, 354-

. of George B. Wood, 19,

118.

organic physics, 12, 311.

Harvest, human, 45, 54.

Hassler, F. R., criticism on the ^las-
sachusetts Survey, reply to. 2, 164.

Hastings. W. G.. development of Law
as illustrated by the decisions re-
lating to the Police Power of the
State, 39i 359-

37

HATCHER-HAYS

GENERAL INDEX

Hatcher, J. B., attempt to correlate
Marine with Non-Marine forma-
tions of middle West, 43, 341.

-origin of the Oligocene and Mi-
ocene deposits of the Great Plains,
41, 113-

Haupt, Herman, computation of the
effect of gradients, 12, 9.

level notes and compass courses

of Seaboard Oil Pipe Line in
Pennsylvania and Maryland, 17,
136.

Haupt. Lewis ]\I., coordination of
methods of expressing thought,
18, 348.

— ■ — -dynamic action of the ocean in
building bars, 26, 146.

— — harbor entrances, physical phe-
nomena of, 25, ig.

maps, scales of, 18, 47.

— - — -Mississippi River problem, 43,
/I-

Nation and waterways, 48, 51.

ocean bars, methods of improv-
ing, 40, 62.

, — breakwater at Aransas Pass.

Tex.. 1899, 38, 135.

-reaction as an efficient agent in

procuring deeper navigable chan-
nels in the improvement of rivers
and harbors, 42, 199.

transportation in the L^nited

States. 46, 171.

— ^waterways, emancipation of the,
44, 42.

Haupt, Paul, ancient protest against
curse on Eve, 50, 504.

— — Burning Bush and the origin of
Judaism, 48, 354.

Jonah's whale, 46, 15 r.

Haverford College Observatory, lati-
tude of, 21, 78.

— School refracting telescope. 6, 22"/.
Hay, Oliver P.. fossil specimen of

the alligator snapper from Texas.
50, 452.

Hay, Oliver P. (continued).

Trionychidse, genera of, 42, 268.

vertebrates of the Carbonifer-
ous Age, 39, 96.

Hayden, F. V., Bear River group,
sections of strata of, 11, 420.

Colorado and New Mexico,

geology of. II, 212, 234.

connecting link between the

Stone and present Age, 10, 352.

— - — fishes, fossil, II, 316, 431.

-fossils from New Mexico and

California, 11, 425.

lignite beds of upper Missouri,

10, 300

Missouri, geological map of the

upper, II, 115.

, — -Valley geology of, 10, 292.

— • — obituary notice of, 25, 59.

— - — Pawnee, Winnebago, and
Omaha languages, 10, 389.

— - — plants, geographical distribu-
tion of, west of Mississippi, 10,

315-
timber, scarcity of, in the far

West, 10, 322.
• Wyoming and Colorado, geol-
ogy of, 10, 463; II, 25.
— - — Yellow and Missouri Rivers,

geology of. II, 112.
Hayes, L L. Arctic expedition of

1866, 8, 3S3.
Haynes, J. L.. nicotin and strychnia,

antagonism between, 16, 597.
Hays, Isaac, catojitric examination of

the eye, i, 97.

color-blindness, i, 265.

— — fossils, Missouri, 2, 183.

— - — genus Tetracaulodon, 2, 105.

— • — Koch's collection of mammalian

remains, 2, 183.
— • — mastodon. 4, 43. 269.

. — Koch's 2, 102.

• Proboscida', 3, 44.

strabismus, operation for, i.

38

PROCEEDINGS, VOLS. 1-50

HAYS-HENRY

Hays, T. Minis, Declaration of Inde-
pendence, bibliography of, 39, 69.

, history of the Jefferson

manuscript draught of, in the
American Philosophical Society,

37, 88.

Fort William Henry, journal

kept during the siege of, 37, 143.
original ms. laws of Province

of Pennsylvania in possession of

the Society, 36, 176.
-William Penn's commission for

the government of Penn.sylvania,

38, 4

Haze, night, self-luminous, 50, 246.

Hazlehurst, Henry, obituary notice
of, Memorial Vohtinc, i, 18.

Head, Egyptian form of. 2, 239.

Health and metabolism, influence of
preservatives and other substances
added to foods upon, 47, 302.

— and ventilation, 10, 8.

— -connection of, with meteorology,

14, 667.
Heat and attraction, 10, 97.

— daily distribution of, 9, 345.

— dispersion of, generated by a gas
burner. 17, 309.

— latent, of expansion, in connection
with luminosit}' of meteors, 14,
114.

— non-periodic, distribution of, in the
atmosphere, 13, 138.

— 'propagation of, 41, 181.

— radiant, 20, 334.

— , — .application of, to glass, i, 159.

— radiation of, 5, 108.

— solar, distribution and transmis-
sion of, 10, 309.

— vibrations caused by, 6, 32.
Heath. E. R.. explorations in Bolivia,

19, 564-
Hebrew etymologies from the Egj-p-
tian Anx ; Enoch ; Anoki ; Enos,
notes on. 29, 17.

— kings, Egyptian element in the
names of 19, 409; 20, 506.

Hebrew (continued).

— phonetics, 29, 7.
Heckewelder, John. Lcnni Lcnape,

words, phrases and short dialogues
in the language of the, Trans. Hist,
and Lit. Co nun., 1, 451.

natives who once inhabited

Pennsylvania and the neighboring
States, Trans. Hist, and Lit. Comni.,
I, I.

and Peter S. Duponceau, In-
dian languages, Trans. Hist, and
Lit. Comm., i, 357.

Heer, Oswald, obituary notice of, 21,
286.

Heilprin, Angelo, flora of northern
Yucatan, 29, 137.

— ■ — 'Polar expedition. 36, 461.

— • — temperate and Alpine floras, of
the giant volcanoes of Mexico, 30,
4-

Heliostat, 2, 97.

Heller and Brightly's new transit, 12,

115-
Hematite, brown, ore banks of

Spruce Creek, Pa., 14, 19.
Hemileucini, 14, 256; 31, 139.
Hemoglobins, crystallographic study

of, 47, 298.
Hemp, North American, medical ac-
tivity of, II, 226.
Hendry, W. A., coal bed in the

Joggins and Albert mine regions,

9, 459-
Henry, Joseph, capillary action, i,

82; 4, 176.
• — • — -electricity, experiments on, 4,

208.

— — -heat, radiation of. 5, 108.
^ heliostat, 2, 97.

induction, two kinds of dynamic,

I, 135-

• , — electrical, 2, 193. 229.

, — electro-dynamic, i, 54, 315.

lightning on telegraph wires,

effects of, 4, 260.
, — protectors, 4, 179.

39

HENRY-HOLOPTYCH

GENERAL INDEX

Henry, Josepli (continued).

liquids, cohesion of, 4, 56, 84.

niaitcr, corpuscular constitution

of, 4, 287.

mechanical power, 4, 127.

Melloni's apparatus. 4, 122.

obituary notice of, 18, 461.

phosi)Iiorescence, 2, 48.

phosphorogenic emanation, 3,

38.

Sun spots, 4, 173.

-thunder storm, effects of a, 2,

III.

— • — • velocity of projectiles, 3, 165.

-water, polarization of, 4, 229.

Hepatoscopy and astrology in Baby-
lonia and Assyria, 47, 646.

Hepiali, 14, 256.

Hercegovina, aus Bosnien und der,
23, 87.

Herdente, 21, 694.

Heredity and variation, 45, 70.

■ — cellular basis of, 43, 5.

— variation and evolution in Proto-
zoa, 47, 393-

Herpetological and Ichthyological
contributions. Cope's, Memorial
J'oliiinc. I, 274.

— notes, 37, 139,
Herpetology of Mexico, 22, 379.

— of tropical America, 11, 147, 496,
S'^i- 553 '• I7> 85; 18, 261: 22, 167;
23, -'/I-

Herschel, John F. W.. obituary notice

of, 12, 217.
Herschel-Stephenson i)ostulate, 12,

395-

Hessian fly, i, 318; 2, 42.

Hewett, Waterman 1'., historical use
of tlie relative pronouns in Eng-
lish literature. 43, S/i'^.

Heyl, I'aul R., conversion of the
energy of carbon into electrical
energy on solution in iron, 49, 49.

Hiller, 11. Al., Rcjang River in
Borneo, 35, 321.

Hindu epic, magic observances in
the, 49, 24.

Hinrichs, Gustavus, oxygen and sil-
ver, atomic weights of, 49, 359.

— ■ — -vanadium, atomic weight of,
50, 191.

Hippotherium, North American spe-
cies of, 26, 429.

Hippuric acid, conversion of benzoic
acid into, 2, 129.

Hirst. Barton C, obituary notice of
R. A. F. Penrose, 48, Iviii.

His'teridre of United States, 13, 273.

Historical societies of our Country,

32, 76.

History, American, from German

archives, 39, 129.
— physical, of Maryland, 3, 158.
— -the new, 50, 179.
Hitchcock, Edward, obituary notice

of, 9, -W3-
Hoar frost, 9, 456.
Hobbs, Wm. Herbert, inland-ice of

the Arctic regions, 49, 57.
— ■ — seismic geology, 48, 259.
Hoffman, Walter J.. cremation

among the Digger Indians, 14, 414.
folk-medicine of the Pennsyl-
vania Germans, 26, 329.
— • — Indian tribal names, 23, 294.

^ Pah-Ute cremation, 14, 297.

Pennsylvania German dialect,

26, 187.
— • — Pensilfani, gshicht fun da al'tii

tsai'tii in, 32, 325.
-^ — Scclish language, vocabulary of

the. 23, 361.
Waitshum'ni dialect, of the

Kawi'a language, vocabulary of

the 23, 372.
Holiday customs in Ireland, 26, ;i77.
Holland, J. W., scientihc work of

Benjamin Franklin. 28, 199.
Holoptychius, occurrence of, in -the

Chemung group in Bedford Co.,

20, 531.

40

PROCEEDINGS, VOLS. 1-50

HOPKINS-HUMB

Hopkins, E. Washburn, magic ob-
servances in Hindu epic, 49, 24.

Hopkinson, Joseph, obituary- notice
of, 6, 12.

Hoppin, J. M., philosopliy of art. 32,
56.

Horizon, inclination of the apparent
to the true, 20, 206.

— of the South Valley Hill rocks in
Pennsylvania, 20, 510.

Horizons, some new Red, 33, 192.
Horn, George H., Anisodactylus of

the United States, 19, 162.
Bostrichida; of the United

States, 17, 540.
— • — Calopasta Lee, 29, 99.

— — Colydiida; of the United States,

17, 555-

— • — Cremastochilus of the United
States, revision of the, 18, 382.

■ ■ Curculionidas of the United

States, 13, 407.

Deltochilum gibbosum, 26, 529.

Euphoria of the United States,

18, 397-

Histeridre of the L'nited States,

13, -73-
Hydrobiini, revision of the, 13,

118.
Meloida of the United States,

revision of the, 13, 88.
obituary notice of John L. Le

Conte, 21, 294.

— — - Selenophorus of the L^nitcd
States, 19, 178.

■ and J. L. Le Conte, Rhynco-

phora of North America, 15, i ; 16,

417-
Horner, William E., mastodon, notes

on the I, 279, 307.
— • — microscopic anatomy, 3, 89.
Horologium Achaz, 34, 21.
Horse, evolution of the, 43, 156.
Horse's eye, worm in a, i, 200.
■ — • stomach, concretion found in, 4,

230.

Horses, osteology of the White River,
35, 147-

— three-toed, 23, 357.

Hot weather, effects of, upon infants,
4. 213.

Houston, Edwin J., gramophone and
telephone records, 25, 144.

hailstones, crystal-studded 26,

529.

muscular contractions follow-
ing death by electricity, 28, ^j.

— ■ — -phosphorus, allotropic modifica-
tion of, 14, 108.

— ^photography by a lightning
flash, 23, 257.

— — Rontgen ray, 35, 24.

telegraph, synchronous multi-
plex, 21, ;i26.
-waterfall sensitive to the human

voice, 12, 515.
and A. E. Kennelly, insulating

medium surrounding a conductor,

the real path of its current, 36, 144.
and Elihu Thompson, efficiency

of dvnamo-electric machines, 18,

58.
Hovey, Edmund Otis, earthquakes,

48, 235.
Huacos potteries of old Peru, 42,

37S.
Hubbard, H. G., larva of ;\Iicromal-

thus debilis, 17, 666.
-and E. A. Schwarz, Coleoptera

of Michigan, 17, 593, 627, 643.
Hubbard, Jesse W., yolk nucleus in

Cymatogaster aggregatus, 31, 358;

33, 74
Hudson and ^Lanhattan Railroad Co.,

tunnel construction of the 49, 164.

— Observatory, astronomical observa-
tions at, 2, 51.

Huebnerian noctuid genera repre-
sented in the North American
fauna, 41, 4.

Humboldt, Wilhelm von, philosophic
grammar of American languages,
22, 306.

41

HUMBOLDT-INDUC

GENERAL INDEX

liuml)oklt, William von (continued).
verl) in American languages,

22, 332.

Humphreys, A. A., obituary notice of,
22, 48.

Hunt, 'J homas Sterry, metalline min-
erals. 25, 170.

-obituary notice of. Memorial

I'oluiiie, I, 63.

-reply to, 14, 216.

Huron disaster, cause of, 17, 212.

Hyatt, Alpheus, phylogeny of an ac-
quired characteristic, 32, 349.

Hybridization, germinal analysis
through, 49, 281.

Hydrobiini, revision of the, 13, 118.

Hydrochloric acid, action of, on
acetobenzoic anhydride, 19, 13.

-conversion of chlorine into, 21,

102.

Hydromice schists, 18, 435.

Hygrometer, dew point, 2, 249, 252.

Hypenoid moths and allied groups,
34, 416.

Hyperostosis, universal, 12, 19.

Hypochlorites, purification of Avater
supplies by, 48, 67.

Hypoglossal nerve in the cat, 25,

99-

Hyrachyus, extinct taperoid, osteol-
ogy of, 13, 212.

Hyrtl's collection, remarks on, 12,
191.

IttKxos, Greco-Egyptian etymology

of, 19, no.
Ibrahim nukic, 25, 183.
Ice erosion on the Blue ^Mountains,

20, 468.

— growth in. 21, 217.
Ichthyology of Alaska. 13, 24.

— of the Antilles. 11, 514.

— of the Maranon, 11, 559-

— of Utah, 14, 129.
Ichthyopterygia, 11, 497-
Iddings, Joseph P., problems in

petrology, 50, 286.

Iguanin«, on the species of, 23, 261.
von Ihering, H., molluscan fauna of

the Patagonian Tertiary, 41, 132.
Imphee, or African sugar-cane, 9,

141.
Imprisonment, effects of secluded,

in production of disease. 3, 143 ;

Trans. Hist, and Lit. Cnmm., 3, 85.
Inclinometer, induction. 2, 237.
Incrustations, patent to prevent, 10,

169.
Indian figures at Safe Harbor, 10,

30, 255. 522.

— inscriptions, 11, 3.
— ■ languages, 10, 389.

— • — - correspondence respecting the.
Trans. Hist, and Lit. Conim., i,

357-

— picture rocks in Fayette County,
Pennsylvania, 21, 687.

— relics from New Jersey, il, 213,
283.

— stone implements. North Amer-
ican, 8, 265.

— -tribal names, 23, 294.

— tribes at Brantford, 18, 378.

— - — and languages of Costa Rica,
14. 4?3.

— Walk of 173,7, 5, 127.

Indiana Co.. Pa., list of elevations

through, 17, 145.
Indians, Beothuk, 22, 40S ; 23, 411;

28, I.

— Digger, 14, 414.

— history, manners and customs of
natives who inhabited Pennsyl-
vania, and neighboring States,
Trans. Hist, and Lit. Comni.. i, i.

— North .\merican. stone imple-
ments of, 8, 265.

— Pah-l'te. 14, 297.

— Tutelo, 21, T.

Induction, (lynamic, by a galvanic

current, i, 135.
-electrical, i, 54. 3f5: 2, 193. 229.
— -electro-dynamic, i, 54. 315.

— inclinometer, 2, 237.

42

PROCEEDINGS, VOLS. 1-50

INFANTS-JONES

Infants, effects of hot weather upon,

4. 213.
Infusoria, new fresh-water, 23, 562;

24, 244; 28, 74.
— , — Hypotrichous, 23, 21.
— undescribed, 33, 338.
Ingersoj], Charles J., obituary notice

of, 9, 260.

Iron (continued).

— • pipes, transmission of sound

through, 5, 118.
Irving, Washington, obituary notice

of, 7, 363.
Isleta Indians, mythic tale of the, 29,

208.
Isomerism, apparent, 2, 75.

of Joseph Bonaparte, 6, Isostasy and mountain ranges, 50,

71-

Isthmian canal, progress of the, 46,
124.

Jackson, Isaac R., obituary notice
of, 2, 217.

James, Edmund J., proportional rep-
resentation, an early essay on, 34,
468.

James, Thomas P., obituary notice
of. 20, 293.

, of William Darlington. 9,

330-
Japanese coin. 8, 264.
— embassy, of i860, 49, 243.
International Congress of Geologists, Jasper and stalagmite quarried by
1885, 23, 259. Indians in the Wyandotte Cave,

Intoxication, alcoholic, influence of, 34, 396.

upon certain factors concerned in Jastrow, ]\Iorris, Jr., Hamites and

Ingersoll, Joseph Reed, obituary

notice of, 10, 513.
, of Henry D. Gilpin. 7,

347-

Ingham, S. D.. effect of lightning on
telegraph wires, 4, 259.

Inks, identification of colored, by
their absorption spectra, 35, 71.

— photographic testing of, 34, 471.

Instruments used at West Point,
N. Y., 3, 151.

Insulating medium surrounding a
conductor, the real path of its cur-
rent, 36, 144.

Semites in the tenth chapter of

Genesis, 43, 173.
• hepatoscopy and astrology in

Babylonia and Assyria, 47, 646.
sign and name for planet in

Babylon, 47, 141.
Jayne, Horace, revision of the Der-

mestidte of the United States, 20,

343-
Jelly-fishes, a new genus of hydroid,

42, II.
Jennings, H. S., heredity, variation

and evolution in Protozoa, 47,

393-
, error in identifying two dis- Joly process of color photograph}-,

tinct beds of. 20, 529. 35, 119.

— 'Ores and limestone from Spruce Jones, Harry C, obituary notice of

Creek, &c., 14, 84. Jacobus Henricus Van't Hoff, 50,
of the South Mountain, 13, 3. iii.

43

the phenomena of haemolysis and
bacteriolysis, 41, 140.

Invertebrates, Miocene, from Vir-
ginia, 25, 135.

lodyrite. vanadates and, from Lake
Valley, Sierra County, N. M., 22,

Iridium, fusibility of, 2, 182, 187, 196.
Iron, chromic, decomposition of, 17,
216.

— detection of, by salicylic acid, 18,
214.

— magnetism of, specific, 10, 358.

— ore belt, titaniferous, 12, 139.

JONES-KENNELLY

GENERAL INDEX

Jones, Harry C. (continued).

and John A. Anderson, absorp-
tion spectra of neodymium chloride
and praseodymium chloride, 47,
276.

and W. W. Strong, absorption

spectra of various potassium,
uranyl, uranous and neodymium
salts in solution and the effect of
temperature on the absorption
spectra of certain colored salts in
solution, 48, 194.

Jones, Howard G., Cumberland or
Potomac coal basin, 19, in.

Jones, Joel, obituary notice of, 7.

387.
Jordan, David Starr, human harvest,

45, 54-

Jordan, Francis, Jr., aboriginal pot-
tery of the middle Atlantic states,
25, 104.

Joule's equivalent, cosmical determi-
nation of, I9» 20.

Judaism, origin of, 48, 354-

Jugal arch, significance of. 34 > 50-

Jupiter-cyclical rainfall, I4i I93-

— Saturn, Uranus and Neptune, re-
lations between the mean motions
of, 12, 435-

Jury, trial by, 9, 209.

Justice, G. :\I., crystallotype of the
Moon, 5, 3'^^- 354-

.Haverford School refracting tel-
escope, 6, 227.

magnetism, 4, 218.

Protococcus Nivalis, 5, 262.

Kane, E. K., arctic exploration, 5,

159, 224, 357-

, — vegetable matter, 5, 159, 266.

Kane, John K., obituary notice of

Thomas Gilpin, 6, 13.
, of Joseph Hopkinson, 6,

12.
^ of Isaac R. Jackson, 2,

217.

Kane, John K., obituary notice (con-
tinued).

. of R. M. Patterson, 6, 60.

, ^ — of Wm. Strickland, 6, 28.

, of John Price Wetherill,

6, 14.
Kane, T. L., Coahuila, 16, 561.
Kansan drift, in Pennsylvania, 37,

84.
Kansas chalk, new testudinate from.

12, 308.
■ — -crctnccous, fishes from, 12, ;i27.

, reptiles of, 17, 176.

, pythonomorpha from, 11, 574.

— new ornithosaurians from, 12, 420.
Keane, Rt. Rev. John J., labors and

achievements of great teachers in

science and philosophy, 27, 47.
• philosophy's place among the

sciences, 32, t,^.
Keasbey, Lindley M., economics,

classification of, 41, 146.
Keen, W. W., universal hyperostosis.

12, 19.
Keim, George de Benneville, obitu-
ary notice of, 33, 187.
Keller, Harry P., copper minerals,

notes on some Chilean, 47, 79.
-new variety of chrysocolla from

Chile, 48, 65.
— ■ — and Philip Maas, dimethyl ra-

ccmic acid, 43, 105.
Kendall, E. Otis, comet of 1842, 3,

67.

Encke's comet, 2, 186.

longitudes in the United States,

I, 141.

solar eclipse, 1846, 4, 253.

-and Walker, comet of 1843, 3,

67.
elliptic elements of Neptune,

4, 37'^-
Kcnnelly, A. E., linear resistance be-
tween parallel conducting cylinders
in a medium of uniform conduc-
tivity, 48, 142.

44

PROCEEDINGS, VOLS. 1-50 KENNELLY-KONIG

Kennelly, A. E. (continued).
and E. J. Houston, insulating-
medium surrounding a conductor,

the real path of its current, 36,

144-
— ■ — 'and Walter L. Upson, humming

telephone, 47, 329.
Kentucky coal field, east, 13, 270.
Kerr, \\'. C, topography as affected

by the rotation of Earth, 13, 190.
Key-dwellers' remains, on the Gulf

coast of Florida, 35, 329, 438.
Keyes. Charles R., attachment of

Platyceras to Paljeocrinoids, and

its effects in modifying the form

of the shell, 25, 231.
Kiche myths, Gods' in, 19, 613.
Kinetic ratio of sound waves to light

waves, 9, 425.
King. C. W., epitaph of M. Verrius

Flaccus, 25, 55.
Kings Alill white sandstone, 20, 666.
Kintzes" firedamp indicator, 21, 283.
Kirkbride. Thomas S., obituary

notice of, 22, 217.
Kirkwood. Daniel, aerolites, relation

of, to shooting stars, 24, iii.
— — -aerolitic epoch of November,

17, 339-
asteroids, mass of, between

'Slavs and Jupiter, 11, 498.
. — relations between the orbits

of certain, 30, 269.
comets and meteors, 11, 215;

22, 424: 24, 242.

^ cosmogony of Laplace. 18, 324.

■ — ■ — fireballs and meteorites in the

stream of bielids, 24, 436.
— - — -meteoric fireballs in the United

States. 16, 590.
. — rings, periodicity of certain,

II, 299.
meteors as observed at Bloom-

ington. Ind., Nov., 1868, 10, 541.

. — of January 2d, 1839, 13, 501.

nebulous planets, limits of sta-

liility of. 22, 104.

Kirkwood, Daniel (continued).

— — planets, origin of, 19, 15.

relations between the mean

motions of Jupiter, Saturn, Uranus

and Neptune, 12, 435.
^ solar system, formation and

primitive structure of, 12, 163.
Sun spots, periodicity of, 11,

94.
— ■ — zone of asteroids and the ring

of Saturn, 21, 263.
Kirkwood's analogy, velocity of light

and, 18, 425.
Kites and balloons, exploration of

the upper air by means of, 48, 8.
Knap, Charles, great Pittsburg gun,

9, 454-
Kneass, Strickland, obituarj- notice

of, 21, 451.
Koch's collection of mammalia, 2,

183.

— mastodon, 2, 102.

Kollock, Lily G. and Edgar F. Smith,
effect of sulphuric acid on the
deposition of metals when using a
mercury cathode and rotating
anode, 45, 255.

— new results in electrolysis,

46, 341-

■ — use of the rotating anode

and mercury cathode in electro-
analysis, 44, 137.

Konig, George A., alaskaite from the
series bismuth sulphosalts, 19, 472.

artificial production of crystal-
lized domeykite, algodonite, &c.,
42, 219.

— — astrophyllite, arfvedsonite and
zircon, from El Paso Co., Colo-
rado, 16, 509.

• burette valve, 14, 218.

chromometry, 18, 29.

— — • cosalite, alaskalite and beegerite,
22, 211.

Konig, Rudolph, French normal fork,
17, 80.

45

KRAEMER-LAW

GENERAL IXDEX

Kraemer, Henry, color in plants, 43,

continuity of protoplasm, 41,

174.
dilute sulphuric acid as a fungi-
cide, 45, 157-
oligodynamic action of copper

foil on certain intestinal organisms,

44, 51-
Krakatoa eruption in 1S83, dust from.

32, 343-
Kramm, H. E., serpentines of coast

ranges of California, 49, 315.
Krauss, Eriedrich, aus Bosnien und

der Hercegovina, 23, 87.

Ibrahim Nukic, 25, 183.

Mohammedaner, ein guslaren-

lied der slavischen, 32, 293.
Krauth, Charles P., obituary notice

of, 20, 613.

Labors and achievements in science

and philosophy, 27, 47.
Lacertilia, osteology of the, 30, 185.
Lachneides, 14, 256.
Lagoa crespata, transformations and

anatomy of. 32, 275.
Lake dwellings, 9, 413, 414.

— Erie, pre-glacial outlet of, 19,
300.

— Superior silver mint-s, 6, 155; 11,
3-7-

Lakes, origin and drainage of the
basins of the great, 20, 91, 95.

Lambert, Preston A., expansions of
algebraic functions at singular
points, 43, 164.

— — new application of Mac Laur-
in's series in the solution of equa-
tions nnd in the expansion of func-
tions, 42, 85.

solution of algebraic equations

in infinite series, 47, in.

, — of linear dififerential equa-
tions of successive approximations,
50, 274.

Kramm, H. E., serpentines of the

Lambert, Preston A. (continued).

straight-line concept, 44, 82.

Lamberton, William A., the narra-
tives of the walking on the sea,
46, 80.

Landa's Mayan alphabet, 19, 153.

Landreth, Burnet, new agriculture,
45, 166.

-persistent vitality in seeds. 45,

5-

Language, international, report on,
25, 312.

— of palreolithic man, 25, 212.

— of science and philosophy, univer-
sal, 27, 21.

Languages, aboriginal, of Queens-
land and Victoria, 42, 179.

— • comparative fitness of, for musical
expression, 9, 419.

— , Indian, correspondence respecting,
Trans. Hist, and Lit. Coniin., i,
357-

— • of the New England aborigines.
New South Wales, 42, 249.

— • of some tribes of Western Aus-
tralia, 46, 361.

— study of, 18, 543.
Laplace, cosmogony of, 18, 324.
Laramie Group near Raton, X. 'SL,

20, 107.
Larva of Micromalthus debilis Lee,

17, 666.
Latitude observations, 46, 165.

— variation of terrestrial, 36, 434.
Launch of the ship Pennsylvania,

3, 103.
Lauterbach, B. F., irrelation of a

polarized nerve, 17, 72S.
Lavender, Thomas, water spouts, 3,

1.34-

Law, the development of. as illus-
trated by the decisions relating to
police power of the State, 39, 359.

— -of Oresme, Copernicus and
Gresham, 47, 18.

46

PROCEEDIXGS, VOLS. 1-50

LAW-LESLEY

Law, Philip H., obituary notice of,
25» 225.

, of William S. Vaux, 22,

404.

observations on Gildas and the

uncertainties of early English his-
tory. 25, 132.

Lea, Henry C. new fossil shells from
Virginia Tertiary, 3, 162.

obituary notice of. 50, iii.

Lea, Isaac, American fresh water
Mollusks, 5f 187, 251.

— — auroras, 6, 162.
Coprolites, 3, 143.

-description of nineteen new spe-
cies of Colemacea, i, 173.

— ■ — fresh water and land shells, i,
285; 2, II, 30, 81, 147, 224, 237,
241, 284: 4, 162.

— — lithodomi perforations, 2, 213.

^lelania Cincinnatiensis, i, 66.

Naiades, 5, 187, 191, 220.

obituary notice of, 24, 400.

• , Richard C. Taylor, 5, 226.

— — Oolitic formation in America,

I, 225.

Pine Grove coal, 2, 229.

reptilian footmarks at Sharp

Mountain, Pa., 5, 91.
— • — turbinated shells. 2, 234.
Lead, native, in gold from Montana,

II, 443-

— solutions, electrolysis of. 24, 428.
Leaf structure, comparative, of the

strand plants of Xew Jersey. 48,
72.
Le Conte, John L., Coleoptera of
Florida, description of new species,

17. 373-

, — Michigan, 17, 593, 669.

Florida Coleoptera, 17, 373,

470.
-geographical distribution of

Coleoptera. 17, 470.
-obituary notice of, 13, 183; 21,

291, 294.

Le Conte, John L.. obituary notice of

(continued).
— ■ — , Charles R. Darwin, 20,

235-

— — , S. S. Haldeman, 19, 109.

■ — — tendencies of scientific culture,

18, 569.
and George H. Horn. Rhynco-

phora of North America, 15, i;

16, 417.
Lee, Richard Henry and Arthur Lee,

calendar of the correspondence of,

38, 114-
Leid}', Joseph, geology, &c., of the

[Missouri headwaters, 7, 10.

obituary notice of, 30, 135.

, Isaac Lea. 24, 400.

Leland, Charles Godfrey, obituary

notice of, 42, xi.
Lenni Lenape or Delaware Indians,

language of the, Trans Hist, and

Lit. Coiinii., I, 451.
Lenthall, John, launch of the ship

Pennsylvania, 3, 103.
Leonard, Charles Lester, X-ray, new

physical phenomena of, 35. 298.
Lepidopterous wing ; specializations

of the, Parnassi-Papilionidfe, 38,

725-
Lesley. J. Peter, Abbeville quarries,

9, 388.

— - — African dialects, 9, 3.

Allegheny Mountains, section

across the, 11, 115.

antiquities in Harris Museum in

Alexandria, 10, 561.

Anx, notes on Hebrew etymolo-
gies from the Egyptian. 29, 17.

— - — -artesian wells, 29, 43.

asphalt. West Virginia, 9, 183.

aurora at Cape Breton, 9, 60.

Becker's aneroid, 7, 342.

, — self registering combined

thermometer and barometer, 7, 339.

— — brown hematite ore banks of
Spruce Creek, &c.. Pa.. 14, 19.

47

LESLEY-LESLEY

GENERAL INDEX

Leslej-, J. Peter (.continued).

Brush Mountain, structure and

erosion of, 13, 503.

chemical analysis of Siluro-

Cambrian limestone beds in Cum-
berland Co., Pa., 17, 260.

— — coal measures on Cape Breton
coast, 9, 93, 167.

■ , — system of southern Virginia,

9» 30.

copper ore slate horizon, 7, 329.

dolomitic limestone rocks of

Cumberland Co., Pa., 18, 114.
Egyptian element in the names

of Hebrew Kings, and its bearing

on history of the Exodus, 19, 409.
fossil ore beds in Bedford

County, Pa., 13, 156.

, belt, 14, 102.

geological structure of Taze-
well County, Va., 12, 489.
• , — Survey of Pennsylvania,

progress of the Second, 20, 537.

Grapeville gas wells, 29, 11.

Greco-Egyptian etymology of

loKxos, 19, no.
Hebrew etymologies from the

Egyptian Anx ; Enoch ; Anoki ;

Enos, 29, 17.
, — word " Sh DI " (shaddai)

23, .303-

— — ice erosion on the Blue Moun-
tains, 20, 468.

— ■ — -insensible gradation of words,
7, 129.

iron-ores of the South [Moun-
tain, 13, 3.

Landa alphabet, 19, 153.

-limestone primary near Chadd's

Ford. Pa., 8, 281.

■ — • — micrometer for ficld-note plot-
ting, 13, 233.

mythical compounds of b.\r^ 10,

U7-
notes on certain models, 19,

193-
obituary notice of, 42, xiii ; 45, i.

Lesley, J. Peter, obituary notice of

(continued).
, Chas. A. Ashburner, 28,

53-
, — - — Edouard Desor, 20, 298,

519-
, William Parker Foulke,

10, 481.
, of John W. Harden, 18,

422.

— ■ — of F. V. Hayden, 25, 59.

, of John L. Le Conte, 21,

291.

, of Leo Lesquereux, 28, 65.

, of James Macfarlane, 23,

287.

, of P. W. Sheafer, 29, 39.

— — oil wells at Brady's Bend, Pa.,

12, 562.
— - — • D'Orbigny papyrus, 10, 543.
-origin and drainage of the

Basin of the Great Lakes, 20, 95.
— ■ — -Pennsylvania lignite, 9, 463.
.petroleum in Eastern Kentucky,

10, 33,, 187.

, — well sections, 10, 22/.

rocks of Cumberland Co., Pa.,

dolomitic limestone, 18, 114.
St. Clairville and Bedford R. R.

and Dunning's Creek fossil iron

ore, 13, 156.
''set" griffin, note on a possible

geographical meaning for, 21, 445.
shells found by H. C. Lewis at

Saltville, 19, 155.
■ — — Siluro-Cambrian limestone beds,

in Cumberland Co., Pa., analysis

of, 17, 260.
— • — spirit of a Philosophical Society,

18, 582.
— - — titaniferous iron-ore belt, 12,

139-
Trias, on an important boring

through, in eastern Pennsylvania,

29, 20.
— - — upthrow fault at Embreville

furnace, E. Tenn., 12, 444.

48

PROCEEDINGS, VOLS. 1-50

LESLEY-LIME

Lesley, J. Peter (continued).

— — violation of the law of debitu-
minization of the American coal
beds coming east, 12, 125.

vortical gales of Januar}', 1864,

9. 361.
Lesley, ^Irs. J. Peter, sketch of

Madam Seller, 29, 151.
Lesle}', Joseph, growth in ice, 21,

217.
outcrop belt of east Kentucky

coal held, 13, 270.
Lesquereux, Leo, American coal

flora 9, 198.

— — branch of the cordaites bear-
ing fruit, 18, 222.

cordaites in the carboniferous

formation of the U. S., 17, 315.

Cours de Botanique Fossile, 19,

287.

fungus in Darlington shales at

Cannelton, Pa., 17, 173.

jNIillstone Grit in the far West,

9, 198.

-North American carboniferous

flora, 16, 397.
, — Carolina Triassic plants

found in Bucks Co., Pa., 19, 16.

obituary notice of, 28, 65.

, of Oswald Heer, 21, 286.

-Silurian land plants in Ohio, 17,

163.
Level for transit instruments, new,

10, ?88.

Levels, railroad and oil well, in
northwestern Pa., 16, 667.

Lewis, Henry Carvill. aurora of
April 16-17. 1882, 20, 283.

great trap-dyke across south-
eastern Pennsylvania, 22, 438.

— -—shells found by, at Saltville, 19,

155-
substance resembling Dopplerite,

20, 112.

-terminal moraine in Penna., 20,

662.

Lewis, James, (prime) right-angled
triangles, and V'2, 9, 415.

self-registering thermometer, 7,

295. 316.

Lcwns and Clark, mss. journals and
field notebooks of, 31, 17.

Leyburn, John, obituary notice of
Joseph Addison Alexander, 7, 320.

Libellulidc'e, second abdominal seg-
ment in, 35, 205.

Liberty and necessitj-, 9, 131.

Life insurance, saving fund. 14, 148.

— span of, 36, 420.

— tables. Philadelphia, 11, 17.
Light and gravity, relative velocities

of, 13, 148.

— and sound, gamuts of, 13, 149.

— cosmical relations of, to gravity,
II, 103.

— polarized, application of, to chem-
ical analysis, 4, 349.

— velocity of, nodal estimation of
the, 19, 4.

, — , simple harmonic relation be-
tween terrestrial gravity and, 10,
261.

, — and Kirkwood's analogy, 18,

-^25.

Lightning, efl'ects of, in deep mines,
10, 2S8.

— , — on telegraph wires, 4, 259, 260.

— photography by, 23, 257.
— -protectors. 4, 179.

— stroke, protection of oil tanks
from, 19, 216.

Lignite, Arkansas peat and, 20, 225.
— -beds of upper ^Missouri, 10, 300.

— groups, geological relations of the,
14, 447-

— • Pennsylvania, 9, 463.

Lilley, A. T., section of Chemung

Rocks at Le Roy, Pa., 21, 304; 23,

291.
Limestone and iron ores, 14, 84.

— primary, near Chadd's Ford, Pa.,
8, 281.

49

LIME-LUDLOW

GENERAL INDEX

Limestone (continued).

— Silurian, relations of the crystalline
rocks of eastern Pennsylvania to,
and the Hudson River Age of the
Hydromice Schists, i8, 435.

Limonites of York and Adams Coun-
ties, 14, 364.
Limulus Polyphemus, embryology of

the, 22, 268.
Lineal measures of the semi-civiHzed

nations of Mexico and Central

America, 22, 194.
Linguistic cartography of the Chaco

region, 37, 178.
Liodon perlatus, 11, 496.
Liquids, cohesion of, 4, 56, 84.
Lisbon, cyclical rainfalls at, 12, 178.
Lithodomi perforations, 2, 213.
Lithologie du fond des mers of M.

Delesse, 16, 238.
Living, cost of, in 12th century, 50,

496.
Livingston, Chancellor, springs for

carriages, 3, 106.
Livingston, Edward. biographical

sketch of, 3, 92; Trans. Hist, and

Lit. CoiiDii., 3, 65.
Locke. John, magnetic observations,

I, 24; 2, 35; 4, 109.

— — replacing cross-hairs in tele-
scope of transit instrument, 3, 102.

new telegraphic clock, 5, 51, 206.

^ safety guard, 2, 41.

terrestrial magnetism, 4, 63.

Lockington, W. N., role of parasitic

protophytes, 21, 88.
Lockycr's " Basic Lines," harmonies

of, 18, 224.
Locomotive boiler, examination of an

exploded, 14, 264.
Locusts, seventeen-year, 5, 209.
Loeb, Leo. cyclic changes in the

mammalian ovary, 50, 228.
tumor growth and tissue

growth. 47, 3.
Longicorna of the United Spates,

4, 371-

Longitude and velocity of the electric
current between Cambridge and
San Francisco, 11, 91.

Longitudes from observations of me-
teors, I, 161.

— in southern Michigan, i, 7.

— of several places in the United
States, I, 141.

— telegraphic determination of, 6,
312; n, 91.

Loomis, Elias, astronomical observa-
tions at Hudson Observatory, 2,

51-
— ■ — -magnetic dip. 2, 176.

— —meteorological observations, 2,
178.

storm of Dec. 20, 1836, i, 195;

2, 178.

storms in February, 1842, 3, 50.

Lorentz, H. A., positive and negative
electrons, 45, 103.

Louis, silver, of 15 sous, struck un-
der Louis XIV, 16, 293.

Loup Fork, formation in New
Mexico, distribution of, 21, 308.

, letter from, 21, 216.

Love, the conception of, in some
American languages, 23, 546.

Lovett, Edgar Odell, certain gener-
alizations of the Problem of Three
Bodies, 48, in.

Lowell, Percival. areography, 41, 225.

— ■ — cartouches of ]ylars, 42, 353.

— • — explanation of the supposed
signals from Alars of December
7 and 8, 1900, 40, 166.

Mars on glacial epochs, 39, 641.

-spectroscopic proof of the re-
pulsion by the Sun of gaseous mol-
ecules in the tail of Halley's
Comet, 50, 254.

Lowrie, Walter H., forces of cos-
mical motion, II, 195.

recession of cosmical nodes,

1 1 , 220.

Ludlow, James R., obituary notice
of, 24, 19.

60

PROCEEDINGS, VOLS. 1-50 LUDLOW-MAGNET

Ludlow, Rev. John, prayer by, 3, 2.
Lunar influence upon weather, 5,
117; 10, 436; 12, 17.

— monthly resemblances to daily
barometric fluctuations, 9, 395.

— occultations of the fixed stars, i,
71, 22S.

— rings, 10, 270.

— tidal wave in Lake Michigan, 7,
37S.

Lyman, Benjamin Smith, brown-
stone, age of the Newark, 33, 5.

Chalfont fault rock, 34, 384.

-coal measure sections near Pey-

tona. West Virginia, 33, 282.

— — horizons, some new red, 33,
192.

mesozoic fault in New Jersey,

31, .314-

— — Yardley fault. 34, 381.
Lysiopetalidse, revision of the, 21,

177.
Lystrosaurus Frontosus, 11, 370,
419.

Maas, Philip, dimethyl racemic acid,
43, 105.

Maber\', Charles F., petroleum, com-
position of American, 36, 126; 42,
36.

McCall, Peter, obituary notice of,
19. 213.

^IcCarter, H. G., petrocene, 18, 185.

McCauiej-, Edward Yorke, Egyptol-
ogy, manual of, 20, i.

inscription on a mummy case in

Memorial Hall, 21, 4S8.

— - — obituary notice of, 34, 364.

^NlcCay, Leroy W., trisulphoxyarsenic
acid. 43, 112.

McClellan, William, falling plate os-
cillograph as a phase meter, 44,
166.

McClune, James, meteors, Nov. 14,
1867, 10, 356.

]McCreath, A. S., analysis of a pure
dolomite, 19, 197.

^IcCuIloh, Richard S., application of

polarized light to chemical analysis,

4. 34Q.
^Nlacfarlane, James, obituary notice

of, 23, 287.
]\lcllvaine, William, new civil and

ecclesiastical calendar, 4, 192.

— — 'Obituary notice of, 6, loi.
^NIcKean, William V., obituary notice

of, 42, 10.
Mackenzie, A. Stanley, some equa-
tions pertaining to propagation of

heat in an infinite medium, 41, 181.
INIacLaurin's series in the solution

of equations and in the expansion

of functions, 42, 85.
]vIc!Master, John Bach, biography of

Benjamin Franklin, 28, 166.
]McQuillen, John H., vivisection of

the brain of a pigeon, 17, 314.
^lacrotus. new species of, 28, J2.
[Magellanic Premium awarded to

Benj. Smith Barton, 22, 369.

• Pliny Earle Chase. 9, 487.

Haupt, Lewis M., 25, 19.

?vlagie, William Francis, association

theory of solutions, 46, 138.
physical notes on ^^leteor Crater,

Arizona, 49, 41.
[Magnesium and its light, 9, 458.
[Magnetic declination, 16, 642.

— dip, I, 146, 151; 4, II, 205.

— experiments, i, 24.

— force and barometric pressure,
solar and lunar diurnal variations
of. 9, 425, 487-

— inclination, relation of to gravity,
10, III.

— meridian, 2, 137.

— observations, i, 185, 294: 2, 35,
69, 83. loi, 150, 176; 3, 90, 175;
4, 109, 218.

[Magnetism, general connotations of,
10, 368.

— of iron, specific. 10, 358.

— ■ Sherwood's discoveries in, I, 23.

— terrestrial, 4, 63 ; 9, 427.

51

MAISCH-MATHEWS

GENERAL IXDEX

Maisch, John AL, obituary notice of,

33, 345-

Maxarios, derivation of, 17, 7.
Malay langnage, Asiatic aftinities of

28, 81.
Malformation, human congenital. 21,

413-
Mallet, John W.. langnage of science,

27, 21.
Mallophaga, systematic position of

the, 24, 264.
Mammalia, 11, 171; 18, 452; 19,

484; 20, 438, 476, 563, 643; 22, I ;

34. 458.

• — classification of Ungulate, 20, 438,

— extinct, in the caves of the United
States, II, 171.

-of the Valley of Mexico, 22, i.

— some Pleistocene, from Petite
Anse, La., 34, 458.

Mammals, Cope's work in the,
Memorial Volume, i, 296.

— gigantic, of the American Eocene,
13, 255.

— Triassic, Dromatherium and Mi-
croconodon, 24, 109.

Man, early, in Oregon, 17, 292.

— paleolithic, language of, 25, 212.
Mangue, an extinct dialect of Nica-
ragua, 23, 23S.

Mansfield, A. K.. refraction tables,

16, 425-
Mansfield, L F., quartz pchlile fmuid

in a toal bed, 21, 343.
Manuscript in cipher, transcript of,

supposed to be astrological, 13,

477-
Maps, comity, of the United States,

9, 350.

— early American, 19, 10.

— scales of, 18, 47.

^Nlarafion, ichthyology of the, ii, 559-
]\Larine and non-marine formations
of the Middle West. 43, .•^41-

— fauna of the miocene period of
United States, 34, 135; 35, 139-

Mars, cartouches of, 42, 353.

— on glacial epochs, 39, 641.

— signals from, 40, 166.

Marsh, B. V., heights of auroras of

Jan. and Feb., 1865, 10, 24.
latent heat of expansion in con-
nection with the luminosity of me-
teors, 14, 114.

]\rarsh, O. C, gigantic mammals of
the .\merican Eocene, 13, 255.

New Rocky Mountain fossils

found in 1870-72, 12, 578.

Marshall Group, geological age of
the, II, 57, 245, 385.

^Marshall, John, derivatives of mono-
and dichlorsalicylic acids, 17, 476.

}iLarshall, Margaret E., anatomy of
Phalxnoptilus, Ridgway, 44, 213.

Marston, Commodore, relics from
Vera Cruz, 11, 83.

Maryland, physical history of. 3, 15S.

Mason, Ebenezer Porter, oljituary
notice of, 2, 7.

observations on Nebula?, i, 206.

Mason, Otis T., ripening of thoughts
in common, 43, 148.

Mason, W. D. H., batrachian foot-
prints in anthracite. 17, 716.

]\L'ison, William Pitt, measurement
of the action of water upon metals,
46, no.

-purification of water supplies by

the use of hypochlorites. 48, 67.

Mass, lelations of, 18, 229.

Massachusetts, trigonometrical sur-
vey of, 2, 60, loi, 150.

Mastodon bones at Boonville, Mo.,

4, .35-

— — in New Jersey, 4, 118, 127.

— Koch's, 2, 102.

— notes on the, i, 279. 307; 2, 183.
Matag.ilpan linguistic stock of Cen-
tral America. J4, 403.

Mathews, R. H., aboriginal languages
of Queensland and Victoria, 42,
179.

PROCEEDINGS, VOLS. 1-50 MATHEWS-MERCER

Mathews, R. H., aboriginal (con-
tinued).

— — , — rock pictures in Queensland,
40, 57-

— • — , Arranda language. Central Aus-
tralia, 46, 322.

Australian aborigines, burial

customs of, 48, 313; 49, 297.

, • .ceremonial stones used by,

48, I, 460.

, , origin, organization and

ceremonies of, 39, 556.

, — tribes, divisions of, 37, 151.

, initiation ceremonies of,

37, 54-

Gundungurra language, 40, 140.

language of the Birdhawal tribe

in Gippsland, Victoria, 46, 346.
languages of New England

aborigines, New South Wales, 42,

249.
native tribes of Victoria, their

languages and customs, 43, 54.
North Australian Tribes, divi-

isions of, 38, 75.
Queensland aborigines, divisions

of, 37. 327.

rock carvings, Australian. 36,

195, 466.

South Australian aborigines, di-
visions of, 39, 78.

, phallic rites and initia-
tion ceremonies of, 39, 622.

Western Australia, languages

of some tribes of. 46, 361.

■ , , native tribes of, 39, 123.

. ■ , sociology of the aborig-
ines of, 44, 32.

Matter, corpuscular constitution of,
4, 287.

— modern views of electricity and,
50, 321.

Alatthew, W. D., osteology of Sinopa,
44. 69.

^lauvais' comet, 4, 67.

]\Iaxwell. J. B., mastodon bones in
New Jersey, 4, 118. 127.

Maya alphabet, 19, 153.
— language. 11,4.

Mayer, A., measurements, i&c. of

echpse of Au^. 7, 1869, 11, 204.

]\Iazatecan language of Mexico, 30,

31.

Mears, J. Ewing, universal hyperos-
tosis with osteoporosis, 12, 19.

[Measures, lineal, of the semi-civi-
lized nations of Mexico and Cen-
tral America, 22, 194.

[Mechanical power, classification and
origin of. 4, 127.

[Mechanics, principle of least-work
and the ether of space, 42, 162.

Medals, coins and, 18, 191. 327.

[Medijeva! sermon books and stories,

21. 49-

Meek, F. B. and F. V. Hayden, fos-
sils, collected in Colorado, New
[Mexico and California, 11, 425.

Megaptera Bellicosa, 11, 516; 12,
103.

[Meigs, Charles D., clitoris, 4, 129.

-corpus luteum, 4, 305.

-cyanosis neonatorum, 3, i74-

— — foetal cranium measurements. 3,
127.

obituary notice of, 13, 170.

[Meigs, John Forsyth, obituary notice
of. 21, 266.

[Meinert, Fr. [Myriapoda Musei Can-
tabrigensis, [Mass., 23, 161.

Melania Cincinnatiensis, i, 66.

Melanoplus, species of genus, 36, 5.

[Melloni's apparatus, application of, to
meteorology, 4, 22.

[Meloid.T of the United States, revi-
sion of the. 13, 88.

[Melville. George W., Polar expedi-
tion. 36, 454.

[Mendelian inheritance, determination
of dominance in, 47, 59.

[Mental analysis, 27, 41.

[Mercer. Henry C, fossil sloth at Big
Bone Cave, Tennessee, in 1S96, 36,
36.

53

MERCER-MICROM

GENERAL INDEX

Mercer, Henrj^ C. (continued).

illuminative writing, 36, 424.

jasper and stalagmite quarried

by Indians in the Wyandotte Cave,

34, 396.
IMerovingian graveyard, 10, 3.
^Merrick, J. Vaughan, obituary notice

of Daniel R. Goodwin, 28, 227.
Merrick, Samuel Vaughan, obituary

notice of, 11, 584.
Merriman, Mansfield, principle of

least-work in mechanics, 42, 162.
-relation between the economic

depth of a bridge truss and the

depth that gives greatest stiffness,

44, 164.
Mesozoic fault in New Jersey, the

great, 31, 3i4-

— ores, 16, 651.

Metabolism, effect of preservatives

on, 44, 66.
Metalline minerals, classification and

nomerclature of, 25, 170.
Metalophodon, dentition of, 12, 542.
Metals, electrical spectra of, 14, 162.

— measurement of the action of
water upon, 46, no.

Metamorphism, 22, 161.

Metazoa, morphology of the excre-
tory organs of, 47, 547-

Meteor Crater, Arizona, 49, 4i-

Meteoric fireballs in United States,
16, 590; 18, 239.

— iron from New Mexico, 10, 330.

— means, 12, 516.

— rings, periodicity of, 11, 299.
Meteorites, arrangement of collec-
tions of, 43, 211.

— possible existence of fireballs and,
in the stream of bielids, 24, 436.

Meteorological methods, modern, 17,
278.

— observations, 2, 178.

__ — at U. S. military posts, 3, 158.

on the Nile in 1873, 14, 632.

stations for, li, 516.

Meteorological (continued).

— peculiarities of New England, 14,
154-

— register at Bois-Chene, 11, 499.
Meteorology, 16, 198, 394.

— and health, 14, 667.

— remarks on Blasius' opinions in,
16, 205.

Meteors, i, 261, 300; 2, 6"], 235, 267;
10, 335. 342, 353, 357, 539.

— of January 2d, 1839, 13, 501.

— of .March 15, 1841, 2, 45.

— of Nov. 14, 1867, 10, 356.

— and the comet of 1866, 22, 424.

— as observed at Bloomington, Ind.,
Nov. 13-14, 1868, 10, 541.

— of Nov. 27-30, 1887, Biela's comet
and the large, 24, 242.

— comets and, 11, 215.

— influence of, on auroras, 12, 401.

— latent heat of expansion in con-
nection with the luminosity of, 14,
114.

• — ■ longitude determinations from cor-
responding observations of, i, 161.
— 'periodical, 2, 18.
Methulc, perchlorate of oxide of, 2,

202.
Metric and English units, tables for

interconversion of, 17, 536.
Metzger, John A., the Filipino; his

customs and character, 44, 6.
Mexican Calendar Stone, Valentini's

theory of the, 14, 663.
^leyer. Otto, miocene invertebrates

from \'irginia, 25, 135.
Miani, African exploration, 10, 95.
Michaux, Andre, journal of, 26, i.
Michaux, Frangois Andre, obituary

notice of, 6, 223.
]\Iichelson, A. A., form analysis, 45,

no.
iNIicroconodon, Triassic mammals,

Dromatherium and, 24, 109.
Micromalthus debilis. larva of, 17,

666.

54

PROCEEDINGS, VOLS. 1-50 MICKOM-MOLLUSKS

^Micrometer for field-note plotting,

Micrometers, preliminary study of
some modern, 46, 187.

Microscope, mirror for illuminating
opaque objects for the projecting
18, 503.

Microscopical examination of fluids,
13. 180.

of timber, with regard to its

strength, 21, 2>2>i-

Migration, industrial, 19, 70.

Miller, Edward, mushroom rocks, 10,
382.

obituary notice of, 12, 2)-2- 581.

Miller, G. A., groups generated by
two operators each of which trans-
forms the square of the other into
a power of itself, 49, 238.

, of orders two and

four respectiveh' whose commuta-
tor is of order two, 46, 146.

Quaternion Group, 37, 312.

relations between substitution

group properties and abstract
groups, 49, 307.

totality of the substitutions on

II letters which are commutative
with every substitution of a given
group on same letters, 50, 139.

transitive substitution groups

that are simply isomorphic to the
symmetric or the alternating group
of degree six, 36, 208.

Millstone Grit in far West, 9, 198.

Mineralog}-, contributions to, 20, 381 ;
23, 30; 24, 23.

Minerals, classification and nomen-
clature of metalline, 25, 170.

— paragenesis of, in the glaucophane-
bearing rocks of California, 45,
183.

Mines, bureau of, 20, 206.

— explosions in, 10, 338; 19, 405.

— fish in, 10, 168.

— silver. Lake Superior, 11, 527.

]\Iint Cabinet, late additions to the,

6, 184.
[Miocene, Dicotylinae of the John

Day, of North America, 25, 62.

— fauna of Oregon, 18, 62,, 370.

— fossils in San Domingo, 12, 571,

572.

— invertebrates from Virginia. 25,

135-

[Mirage, lateral and vertical, i, 188.

[Mirror for opaque objects for the
projecting microscope, 18, 503.

}vlississippi River, North West Ter-
ritory and the sources of the, 3,
140.

— — problem, 43, 71.

]\Iissouri River, geology, &c., of the

headwaters of the, 7, 10.
_ — — and Yellow River, 11, 112.

— — lignite beds of, 10, 300.

— Valley, geology of, 10, 292.
}klitchel, O. [McK., obituary notice

of, 9, 147-

]\Iitcheil, James T., original ms. laws
of Province of Pennsylvania in
possession of the Society, 36, 176.

[Mitchell, John K,. obituary notice of,
6, 340.

[Mitchell, S. Weir, obituary notice of
Henry Charles Lea, 50, xxxvii.

[Models, notes on certain, 19, I93-

[Modification of animal organisms,
proofs of the eft'ects of habitual use
in, 26, 541.

[\Iohammedaner. ein guslarenlied der
slavischen, 32, 293.

[Molecular vibrations, vital, 29, 80.

[Mollusca of the Cretaceous Forma-
tion, 8, 57.

— of the West India Islands, 12, 56.
[Molluscan faunule. from the Creta-
ceous of [Montana, 42, 188.

[Mollusks, American fresh water, 5,

251-
— , .muscular fibers in foot of,

5, 187

55

MOLYB MOUND

GEXERAL INDEX

Molybdenite from neighborhood of
Reading. 5, '2-'/i.

Money, historical sketch of Conti-
nental paper money, i, 248; 3, 57;
Trans. Hist, and Lit. Comiii., 3, 3.

— Turkish paper, 6, 154, 215.
Monks, Sarah P., Columella and

stapes in some North American
turtles, 17, 335.

]Monoclilordinitropheno], &c., a new,
17, 706.

Monocotyledons and the dicotyledons,
taxonomic charts of the, 46, 313.

Montgomery County, Maryland, geol-
ogy of, 5, 85.

— — , Virginia, geology of. 24, 61.
Montgomery, Thomas H., Jr.. cellu-
lar basis of heredity, 43, 5.

morphological superiority of the

female sex, 43, 365.
morpholog}' of the excretory

organs of Metazoa, 47, 547.
i\Ioon, color of the, 14, 155.

— crystallotype of the, 5, 312, 354.

— daguerreotypes of, 5, 208; 6, it,/.
Mooney, James, funeral customs of

Ireland, 25, 243.

— — holiday customs in Ireland. 26,

377-
medical mythology of Ireland,

24, 136.
]\Ioore, George T.. primitive living

representative of the ancestors of

the plant kingdom. 47, 91.
]Moore, Samuel, obituary notice of,

8, 53-

]\Ioraine, terminal, in Pennsylvania,
20, 662.

^loreau de St. Mery and his French
friends in the American Philosoph-
ical Society, 50, 168.

^lorehouse, George R., obituary no-
tice of Lewis Allaire Scott, Memo-
rial Volume, I, 49-

Morley, Edward \\'., obituary notice
of Oliver Walcott Gibbs, 49, xix.

Morlot, A., Copper Age in the United
States, 9, III, 119.

]\Iorris, Ellwood, turbine, 3, 169.

Morris, Harrison S., obituary notice
of Joseph Wharton, 48, Ixxi.

Morris J. Cheston, Carthaginian
tombstone, 38, 73.

dodecahedron, relation of the

pentagonal, found near ^Marietta,
Ohio, to Shamanism, 36, 179.

ethics of Solomon, 33, 310.

fac-simile of Declaration of In-
dependence, 37, 81, 177.

Genesis XI.. 1-9 as a poetic

fragment, 35, 305.

■ Hebrew phonetics, 29, 7.

obituary notice of Henry Duval

Gregory, Memorial J'oliime, i, 123.

, of Hy. Hartshorne, 39, i.

Shamanism, 36, 179.

— • — -tuberculosis in animals, 33,

153-
— • — vital molecular vibrations, 29,

80.
Morris, John G., historical societies

of our Country, 32, 76.
Morrone, Josepho ]\Iaria, Lexicon

Cochin-Sinense Latinum ad usum

Missionum, Trans. Hist, and Lit.

Comvi. 2, 185.
-vocabulary of the Cochinchinese

Language, Trans. Hist, and Lit.

Cojiini.. 2, 125.
[Mortality of male children, excessive,

4, 212.
[Morton, Samuel George, Egyptian

form of head, 2, 239.
Morton, Thomas G., obituary notice

of, 42, 7.
[Mososauroid reptile, new, 11, 116.
Mososaurus brumbyi, 11, 497.
— -maxinuis, 11, 571.
Motion, forces of Cosmical. 11, 195.
Mould, a grass-killing slime. 45, 271.
Mound, the great, near Washington,

Adams Co., Miss., i, 305.

06

PROCEEDINGS, VOLS. 1-50

MOWER-NICHOLS

Slower, G., meteorological observa-
tions in U. S. military posts, 3,
158.

Muhlenberg. F. A., obituary notice of
C. P. Krauth, 20, 613.

Plummy case, inscription on a. in
Memorial Hall, 21, 488.

Munnikurrun Hot Springs, mineral
deposit from. 7, 14.

Ivlunro, Dana C., cost of living in
I2th century. 50, 496.

^lunroe, Charles E., detonation of
gun cotton, 48, 6g.

— — -propagation of explosions in
mixtures of petroleum vapor with
air in tubes, 49, 203.

Munster's cosmography, 18, 443.
Muscular contractions following

death by electricity, 28, t,"/.
]\Iusic of the spheres, 13, 193.
Muskokee language, 11, 301.
Musquito Coast, vocabularies from

the, 29, I.
Mylodon annectens, 11, 15.

— teeth and ungual phalanges of, 34,
350.

!Myriapoda, morphology of, 21, 197.

— Musei Cantabrigensis, Mass., 23,
161.

- — -revision of Lj'siopetalidae, 21, 177.
Mythologv, medical, of Ireland, 24,
136.

;; letters which are cummutative
with every substitution of a given
group on the same letters, 50, 139.

Xagualism, zZi H-

Naiades, 5, 187, 191, 219. 220.

Names of animals and plants errone-
ously paired in synonymy, 42, 263.

Nansen. Fridtjof, Norwegian Polar
Expedition, 1893-96, 36, 442.

Nanticoke dialect, 31, 325.

Natchez language, 13, 483.

Nation, and the waterways, 48, 51.

Natural Bridge of \'irginia, 21, 699.

NaturaHsm, scientific, 41, 145.
Nature, book of, 27, 27.
Nature's reforesting. 18, 26.
Nebulae, observations on, i, 206.
Nebular action in the Solar System,
16, 184.

— Hypothesis. 9, 441: 10, 150: 17,

341-

Nebulous planets. 22, 104.

Necessity, liberty and. 9, 131.

Neill, John, obituary notice of. 19,
161.

Neodymium chloride and praseodym-
ium chloride, absorption spectra
of, 47, 276.

Nepheloscope, 2, 12S.

Neptune, elements of. 4, ZZ-, 339-

— ephemeris of, 5, 20.

Nerve, irrelation of a polarized, 17,

7-'8.
Nervo-muscular sensibility in man,

6, 291, 295.
Nervous system, origin and signifi-
cance of the primitive, 50, 217.
Nettleton, E. S., Venango, Co. oil

well records, 16, 429.
Neutral points, Arago's, Babinet's

and Brewster's, comparative visi-
bility of, 10, 21},.
Newberry, J. S., origin and drainage

of the basins of the Great Lakes,

20, 91.
Newcomb, Simon, obituary notice of,

49. iii-

New England, meteorological pecu-
liarities of, 14, 154.

— • — N. S. Wales aborigines, lan-
guages of the. 42, 249.

New ^lexico and California, fossils
from. II, 425.

geology of. II, 212, 234.

New Red horizons, ZZ', I9--

Nichols, Edward L., efifects of tem-
perature on phosphorescence and
fluorescence. 49, 267.

NICHOLS-OLIGOCENE

GENERAL INDEX

Nichols. M. Louise, spermatogenesis
of Oniscus asellus Linn., with
especial reference to the history of
the chromatin, 41, 77.

Nicollett, J. N., astronomical obser-
vations, 2, 178.

Map of tlie North West Terri-
tory and the geographical explora-
tion of the sources of the Missis-
sippi, 3, 140.

Nicotin, antagonism between, and
strychnia, 16, 597.

Nipher, Francis E., disruptive dis-
charges of electricity through
flames, 50, 397.

— elimination of velocity effects in
measuring pressures in a fluid
stream, 45, -/-.

— • — optical phenomenon, 50, 316.

Nitrogen, sources of error in the de-
termination of the atomic weight
of, 43, 116.

Noanama dialect of the Choco Stock,
35, 202.

Noctua Linn., results obtained from
a search for the type of, 41, 4.

Noctuidae, North American, 21, 134.

Nodes, recession of cosmical, 11,
220.

Nolinete, desert group, 50, 405.

North Carolina auriferous gravels,
19, 477-

— ■ — -fresh water fishes of, 11, 448.

— • — Triassic plants found in Bucks
County, Pa., 19, 16.

North-east boundary. 4, 53.

North-west Territory and the sources
of the Mississippi, 3, 140.

Northampton County, Pa., glacial
drift of, 18, 84.

Norton, W. A., constitution and mode
of formation of the tails of comets,
3, io8.

Nuclei in dust-free wet air, distribu-
tion of, 46, 70.

Nukic, Ibrahim, 25, 183.

Nulty, Eugenius, determination of
azimuths, 4, 234.

— ■ — magic cyclovolute, 4, 125.

Numerals, radical significance of, 10,
28.

Numeration, octonary. and its appli-
cation to a system of weights and
measures, 24, 296.

Nutritive processes, influence of men-
tal and muscular work on. 49, 145.

Nuttall, Thomas, obituary notice of,
7, 297.

Nyctinomus, on the genus, and de-
scription of two new species, 26,
558.

Observatories, construction of, 4, 209.

Occultations, Lunar, of the fixed
stars, I, 228.

Ocean bars, methods of improving,
40, 62.

Octonary numeration, 24, 296.

Ocular phenomena. 4, 239.

Oedogonium Huntii. 10, ■^,},i.

Ogburn, John H., comparison of lati-
tude observations at Sayre Observa-
tory, South Bethlehem, and at
Flower Observatory. Philadelphia,
46, 165.

Ohio, geology of western, 2, 120.

Oil, adulterations in, 22, 296.

— region, Pennsylvania, 10, 109.

— springs of the West, 8, 262.

— tanks, protection of. from light-
ning stroke, 19, 216.

— use of, in storms at sea, 23, 383.

— well levels in northwestern Pa.,
16, 667.

— — -records, 16, 3. 46, 429: 18, 9.
— ■ — -section, Hyner's, 17, 670.
-surveys for rectifying levels,

railroad and, 17, 17.

— wells at Brady's Bend, Pa., 12,
562.

Oligoccne and Miocene deposits of
the Great Plains, 41, 113.

58

PROCEEDIXGS, VOLS. 1-50 OLIVER-OSTEITIS

Oliver, Charles A., blindness from
congenital malformation of the
skull. 41, 161.

color-signals, regulation of, in

marine and naval service, 43, 207.

■ Governmental supervision of

ports necessitating normal percep-
tion of color, 44, 40.

• hereditar\- optic-nerve atrophy,

32, 269.

— • — -obituary notice of Joseph Zent-
mayer, 31, 358.

— ■ — -subjective after-color, 23, 500.

Omaha language, 10, 389.

Onion disease. 10, 168.

Oniscus asellus Linn., spermatogen-
esis of, 41, "/"/.

Oolitic formation in xA.merica, i, 225.
Ophidia, lungs of the, zZi 217.
Ophidiens, deux especes nouvelles

des, de Mexique, 25, 181.
Opisthenogenesis, 43, 289.
Optic nerve atrophy, hereditary, 32,

269.
Optical phenomenon, 5, 16; 50, 316.
Optics, physiological, disputed facts

in, 16, 218.
D'Orbigny papyrus. 10, 543.
Ord, George, obituary notice of

Clement C. Biddle, 6, 158.

— ^, \Vm. Mcllvaine, 6, loi.

Orders two and four, groups of, 46,

146.
Ore banks, brown hematite, of Spruce
Creek, &c.. Pa., 14, 19.

— belt, fossil, 14, 102.

— bombshell, origin of, 47, 135.

— fossil iron. St. Clairville and Bed-
ford R. R. and Dunning's Creek,
13, 156-

^ f ranklinite, 9, 88.

— -radium in an American. 43, 157.

Oreodontidse, synopsis of the species

of, 21, 503.
Ores, Mesozoic, 16, 651.
Oresme, Copernicus and Gresham,

law of. 47, 18.

Organic form?, creation of, 12, 229.

— remains, position of, 4, 2-j.

— variation, 24, 113.

Organisms, origin of the markings

of, 43, 393-
Organs, transplantation of, 47, 677.
Orion, photographing the nebula of,

19, 156.
Ornithosaurians, new, from Kansas,

12, 420.
Orr, Hector, hail storm, ]\Iav 8, 1870,

II, 438.
Orthography and pronunciation, laws

of English, 8, 285 ; 9, 39.

— report of Committee on amended,
26, 306.

Ortmann, A. E., destruction of the
fresh-w^ater fauna in western
Pennsylvania. 48, 90.

— — geographical distribution of
freshwater decapods and its bear-
ing upon ancient geographv, 41,
267.

mutual affinities of the species

of the genus Cambarus, and their
dispersal over the L'nited States,
44, 91-

selection and separation, nat-
ural, 35, 175.

Orton. J., cold blooded vertebra from
Peru, 17, Zi-

Osborn, Henry Fairfield, Cope's work
in the mammals, Memorial Vol-
ume, I, 296.

— ■ — evolution of the horse, 43, 156.

Triassic mammals Dromatheri-

um and Microconodon, 24, 109.

Osborne, photo-lithography. 9, 483.

Oscillation, sethereal, 12, 411.

— -explosive, 12, 403.

Oscillations, influence of, moving
with the velocity of light. 9, 405.

Oscillograph, use of the falling plate,
as a phase meter, 44, 166.

Osmazome, conservation of. in roast-
ing. 31, 318.

Osteitis deformans, 41, 143.

59

OSTEOLOGY-PEACH

GENERAL INDEX

Osteology, human, ii, 117.
Outerbridge, A. E., electrical spectra

of metals, 14, 162.
Ovary, mammalian, cyclic changes in

the, 50, 228.
M-oxybenzoic acid, action of gas

from AS..O3 and HNO.i upon, 25,

194.
Oxygen and silver, true atomic

weights of, 49, 359.

— discovery of, in the Sun by pho-
tography, 17, 74.

Packard, Alphcus S., Arthropoda,

classification of the, 42, 142.
— ■ — ■ Ceratocampidie, Hemileucidce,

&c., 31, 139.

Cochliopodid;c, 31, 8^.

'discovery of the thoracic feet in

a carboniferous Phyllocaridan, 23,

380.

— — Lagoa crispata, 32, 275.

Limulus polyphemus, embryol-
ogy of, 22, 268.

• Lysiopetalidse, revision of, 21,

177-

Alallophaga, systematic position

of the, 24, 264.

^ markings of organisms (Pcecil-

ogenesis) due to the physical rather
than to the biological environment,
43, 39.3-

— — • Myriapoda, morphology of, 21,
197-

opistlienogenesis, 43, 289.

Pah-Ute cremation, 14, 297.
Paljeocrenoids, attachment of Platy-

ceras. 25, 231.
Palc-eolithic man, language of, 25,

212.
Palaeontology, contributions to, from

the Museum of the 2nd Geological

Survey of Pa., 16, 621.
Paleozoic area of Arkansas south of

the Novaculite region, geology of

the, 36, 217.

Paleozoic (continued).

— rocks of Blair Co., Pa., 17, 349.
of Lehigh and Northampton

Counties, 17, 248.

-of Pennsylvania, measured sec-
tion of, 16, 519.

Palladium, 43, 332.

Palms, course and growth of fibro-
vascular bundles in, 21, 459.

Panama and San Domingo, fossils
common to, 12, 572.

Papiamento jargon, 22, 299.

Papyrus, D'Orbigny, 10, 543.

Parabolic motion, oscillation and gen-
eral equation of, 10, 261.

Paraboloids, cometary, 19, 18.

Parana, Brazil, geology of diamantif-
erous region of, 18, 248, 251.

Paris Book E.xhibition of 1894, 34,
12.

Parker, G. H., origin and significance
of the primitive nervous system,
50, 217.

Parthenogenesis, review of, 42, 275.

Passamaquoddy tongue, 22, 240.

— Wampum records, 36, 479.
Patagonian Tertiary, Molluscan fauna

of the, 41, 132.
Patterson, C. Stuart, obituary notice

of Frederick Fraley, 40, i.

-problem of trusts, 42, 15.

Patterson, Robert, obituary notice of

William E. Du Bois, 20, 102.

, of Franklin Peale, 11, 597.

Patterson, Robert M., Centennial

Address, 3, 3.

— — electricity from steam, i, 320.
— ■ — -French and American standard

weights, 4, 153.

obituary notice of, 6, 60.

-Sherwood's discoveries in mag-
netism, I, 25.

Pawnee language, 10, 389.

Peach I'ottom slates, 18, 366.

Peach trees, revival of, by applica-
tion of potash to roots, 11, 237.

60

PROCEEDINGS. VOLS. 1-50

PEALE-PERSON

Peale, Franklin, antique stone hand-
liammer, 9, 401.

coinage, on the process of pre-
paring and reproducing dies for,
and medalic purposes, 6, 95, 106.

Delaware Water Gap, sound-
ings at the, 9, 451.

gum-elastic goods, manufacture

of 4, 221.

Indian stone implements, North

American, 8, 265.

-man, prehistoric, and his imple-
ments, 7, 411.

— ■ — -obituary notice of, 11, 597.

, of }klatthias W. Baldwin,

10, 279.

. of Samuel Moore, 8, 53.

pottery of Illinois, ancient, 9,

240.

, — of Stone Age, 10, 243, 430.

skater's reel, 6, 179.

valves, new form of, 6, 243.

Peat, American condensed, 16, 656.

— deposits, phenomena of, 50, 161.

— and lignite. Arkansas, 20, 225.
Peckham, S. F., bitumens, genesis of.

10, 445; 37. 108.

petroleum, 36, 103.

Peirce, Benjamin, Erman's orbits of
the periodical meteors, 2, 21.

^ perturbations of Uranus by

Neptune, 5. i5-

Peirce C. Newlin. obituary notice of

"William G. A. Bonwill. Memorial
Volume, I, 206.

Penn's commission for the govern-
ment of Pennsylvania during his
first visit to England. 38, 4.

Pennington. Mary E. and Edgar F.
Smith, tungsten, the atomic mass
of, 33, Z2>^-

Pennsylvania, bi-centennial of the
founding of, 20, 497.

— forests, present condition and
future prospect of, 33, 153.

— geology of southwest, 18, 289.

Pennsylvania (continued).

— German dialect, grammatic notes
and vocabulary of the, 26, 187.

— great trap dyke across southeast-
ern, 22, 438.

— launch of the ship, 3, 103.

— -laws of province of, in original
ms. in possession of the Society,
36, 176.

— lignite, 9, 463.

— oil region, 10, 109.

— Second Geological Survey of, 16,
55: 20, 537; 22, 86.

— social and intellectual state of the
Colony of, prior to 1743, 3, 119;
Trans. Hist, and Lit. Comm., 3, 41.

— terminal moraine in, 20, 662.
Penrose, Richard Alexander Fuller-
ton, obituary notice of, 48, Iviii.

Pensilfani, Gshicht fun da al'ta tsai'-
ta in, 32, 325.

Pepper, Edward, eucalyptus in Al-
geria and Tunisia, 35, 39.

Pepper, William, memorial meeting
in honor of, Memorial Volume, i,

133-

— ■ — -obituary notice of James Cop-
land. II, 525.

. of John Forsyth Meigs,

21, 266.

Rontgen ray, remarks on, 35, 34.

and Mears, Keen and Allen,

universal hyperostosis associated
with osteoporosis, 12, 19.

Perch, etheostomine, 11, 261.

Pericles and Apollonius of Tyre, 37,
206.

Periptychus, brain of, 20, 563.

Perissodactyla. systematic arrange-
ment of the order, 19, 2)77-

Perissodactyles, new, from the Bred-
ger Eocene, 13, 35.

Permian formation of Texas, his-
tory of the, 19, 38; 20, 447, 628.

Perry County faults, 21, 218.

Personal equation, 34, 337.

61

PETER-PHOSPHOR

GEXERAL INDEX

Peter, William, obituary notice of,

6, 115.
Petrocene, 18, 185.
Petroleum, composition of American,

36, 126; 42, T,(^.

— genesis of natural gas and, 36, 9,^,
116.

— in eastern Kentucky, 10, 33, 1S7.

— nature and origin of, 36, 103.

— ^occurrence of, in the cavities of

fossils, 36, 121.
— , origin of Pennsylvania, 36, 112.

— reaction, chemical preparation
from a, 18, 44.

— vapor, propagation of explosions
in mixtures of, with air in tubes,
49. 203.

— well sections, 10, 22~.
Petrology, problems in, 50, 286.
Pettit, Henry, obituary notice of

Joseph Miller Wilson, 42, i.
Phatenoptilus, Ridgway, 44, 213.
Pharmacopccia Londinensis Collega-

rum, 9, 224.
Phenacodus, brain of, 20, 563.
Philadelphia, glacial deposits at, 14,

— health of, 9, 26.
— 'life tables, 11, 17.

— public buildings, erroneous state-
ments concerning foundation of
tower of, 16, 2>i7-

Phillips, Alexander H., radium in an
American ore, 43, 157.

Phillips, Everett F., inheritance in
female line, of size of litter in
Poland China sows, 45, 245.

parthenogenesis, 42, 275.

Phillips, Francis C, petroleum, gen-
esis of natural gas and, 36, 116.

, — , occurrence of, in the cavi-
ties of fossils, 36, 121.

Phillips, Henry, Jr., almanacs, early
Philadelphia, 19, 291.

America, two early maps of, 19,

10.

Phillips, Henry, Jr. (continued).

— — Codex Ramirez, with a transla-
tion, 21, 6t6.

— ■ — -coins and medals, 18, 191, 327.

— ■ — collections of American archae-
ology in United States, 21, iii.

Congo Independent State, 26,

459-

— — correct name of the last letter
of the English alphabet, 21, 330.

earthquake at Aix-la-Chapelle,

18, 216.
— • — folk-lore of Philadelphia audits

vicinity, 25, 159; 30, 246.
medals struck to commemorate

the battle of Waterloo, 18, yS,.
]\Iimster's cosmography. 18,

443.
— • — -obituary mjtice of, Meinorial

I'olinuc, I, 26.

, of Peter McCall, 19, 213.

— • — -onituary notices, list of, in

Transactions and Proceedings of

American Philosophical Society,

26, 289.
— • — stone implements in Africa and

.Asia, recent disco\'eries of, 19, 53.
— • — supposed Runic inscription at

Yarmouth, Nova Scotia, 21, 491.
Phillips, Henry M., obituary notice

of, 22, ■J2.

prize awarded. 34, 173; 39, 339.

Philosophical Society, spirit of a. 18,

582.
Philosophy, phases of modern. 12,

289, 317, 361.
Philosophy's place among the

sciences, 32, ;>,^.
Phonetic writing, ikononiatic method

of, 23, 503.
Phonograph reccjrd, microscopical ob-
servations of, 17, 531.
Phonology of the Wyandots, 4, 26S.
Phosphorescence, 2, 46.

— and fluorescence, effects of tem-
perature on, 49, 267.

62

PROCEEDINGS, VOLS. 1-50 PHOSPHORIC-PLATY

Phosphoric acid, in agriculture, 8,

378.
Phosphorogenic emanation, 3, ^8.
Phosphorus, allotropic modification

of, 14, 108.
Photodynamics, 19, 203,262,354,446.

567; 20, 235, 237, 406, 476, 566,

638; 21, 120, 590.
Photogrammetry, civil and mihtary,

30, 229.
Photographic rays, invisible, 3, 179.
Photographs, Siamese, 10, 201.
Photography, 9, 281, ^72.

— astronomical, pertaining to work
■with a portrait lens, 46, 417.

— by a lightning flash, 23, 257.

— composite, 22, 360.

— , — , applied to handwriting, 23, 433.
Photo-lithography, 9, 483.
Phyllocaridian, discover}^ of the

thoracic feet in a Carboniferous,

23, 380.
Phylogeny of an acquired character-
istic, 32, 349.
Physical geography of the United

States, 16, 61.
Physics, organic, 12, 311.
Physostomi fossil, 12, 52.
Pickering, Edward C, international

Southern telescope, 45, 33.
Pieri-nymphalidae, specializations of

the Lepidopterous wing, 37, 17.
Pierids, descent of the, 39, 4.
Pierres a eceuilles en Europe, 17,

714.
Pigeon, vivisection of the brain of a,

17, 3U-

Piggot A, S.. Colombian guano, 6,

189.
Pine Grove coal, 2, 229.
Pipes, iron, transmission of sound

through, 5, 118.
Plagopterinas and Ichthyology of

Utah, 14, 129.
Plane grating, adjustment for, similar

to Rowland's, 48, 166.

Planet, name of, in Babylon, 47, 141.

— unknown, prediction of 13, 237.
Planetary mass, correlations of, 13,

239-

— node between Mercury and Vul-
can, 13, 252.

— series, comparison of, 13, 471.
Planeto-taxis, 13, 143.

Planets, determination of the general
perturbation of the minor, 31, 124.

— existence of, about the fixed stars,
49, -'22.

— intra-asteroidal, rotation of the,
13, 145-

— nebulous, stability of, 22, 104.
— -origin of the, 19, 15.

— primary, analogy of periods of ro-
tation of, 5, 97.

Plant-breeding, forward movement
in, 42, 54-

— kingdom, most primitive living
representative of the ancestors of
the, 47, 91.

Plants, Arctic, 6, 186.

— influence of sea water on distri-
bution of, 50, 457.

— new crystalline compounds in
higher, 25, 124.

— ■ North Carolina Triassic, found in
Bucks County, Pa., 19, 16.

— odor and temperature in, 10, 354.

— sand dune, of Bermuda, compara-
tive leaf structure of the, 47, 97.

— ■ Silurian land, in Ohio, 17, 163.

— west of Mississippi, geographical
distribution of, 10, 315.

Platinum, 2, 196.

— -new compound of, i, 94.

Piatt, Franklin, character of some
Sullivan County coals, 18, 186.

— • — and R. H. Sanders, section of
Palaeozoic rocks, Blair County,
Pa., 17, 349.

Platyceras, attachment of, to Palse-
ocrinoids, and its effects in modi-
fying form of the shell, 25, 231.

63

PLATYP-PRIME

GENERAL INDEX

Platjpterices, North American, 14,
256.

Plesiosaurian reptilia, structure of
the skull in the. and on two new
species from the Upper Cretace-
ous, 33, 109.

Pleurodira from Wyoming Eocene,
12, 472.

Poebrotherium, 14, no.

Poecilogenesis, 43, 393.

Polar Expedition, some results of the
Norwegian, 1893-96, 36, 442.

polarity, density and sethereal, 12,
407.

Polarization, mechanical, of mag-
netic needles, 10, 151.

— sky light, 10, 151, 196.
Polarized light, application of, to

chemical analysis, 4, 349.

Police power of the State, 39, 359.

Polysynthesis and incorporation as
characteristics of American lan-
guages, 23, 48.

Pool, zoology of a Colorado, 14,

139-
Populations, remains of, in Eocene
plateau of North Western Mexico,

14, 475-
Port Kenedy Bone Cave, 12, 15,

73-

Portage, equivalent of the New
York, in Perry County, Pennsyl-
vania, 21, 230.

Porter, T. C, Indian figures cut in
rocks at Safe Harbor, Lancaster
Co., Penna., 10, 30.

, — inscriptions, 11, 3.

Potassium, globular, i, 166.

Pottery, aboriginal, of the ^liddle
Atlantic States, 25, 104.

— , • — of Illinois 9, 460.

— of the Stone Age, 10, 243. 430.
Potts, William John, obituary notice

of. Memorial Volume, i, 36.

, Thomas II. Dudley, 34,

102.

Powel, Samuel, Franklinite ore, 9,
88.

Power, classification and origin of
mechanical, 4, 127.

Prayer, a, 3. 2.

Precipitins, specific, and their med-
ico-legal value in distinguishing
human and animal blood, 41, 407.

Prediction, recent confirmation of
an astronomical. 13, 470; 18, 209.

Pre-glacial outlet of the basin of
Lake Erie into that of Lake On-

. tario, 19, 300.

Prehistoric man and his implements,

7, 411.
Prescott, Alliert B., role of carbon,

43, 102.
Preservatives, influence of, upon

health and metabolism, 47, 302.
President's Address, 5, 360; 6, 67.
Price, Eli K., family as an element

of government. 9, 295.
— ■ — -Glacial epochs, 16, 241.

Nature's reforesting, 18, 26.

obituary notice of, 23, 572.

, of Chief Justice John M.

Read, 14, 271.
, of Oswald Thompson, 10,

211.
phases of modern philosophy,

12, 289, 361.
— • — 'Rockery at the LIniversity of

Pa., 20, 1 19.

-sylviculture, 17, 197.

trees for the Park, 16, 340.

-trial by jury, 9, 209.

Price, J. Sergeant, obituary notice

of. Memorial Volume, i, 57.
Prime, Frederick, glacial drift of

Northampton County, Pa., 18, 84.
— • — obituary notice of Thomas

Miitter Cleniann. 33, 177.
— — - PaliTozoic rocks of Lehigh and

Northampton Counties, 17, 248.
— ■ — -varying ratio between gold and

silver, 34, 49.

64

PROCEEDIXGS, VOLS. 1-50

PRINCE-RATIO

Prince, J. Dyneley, modern Dela-
ware tale, 41, 20.

— • — Passamaquoddy wampum rec-
ords, 36, 479.

, — witchcraft tales. 38, 181.

and Frank G. Speck, dying

American speech-echoes from Con-
necticut, 42, 346.

Princeton, explosion of gun on ship,
4. 47-

Priority, matter of, 34, 67.

Prison system of Pennsylvania, 21,
651.

Problem, fifteenth, 18, 505.

Proboscidse, 3, 44.

Proboscidian, new, 16, 584.

Procamelus occidentalis, brain of,
17, 49-

Procyon, motions of, and of Sirius,
4. II-'-

Projectiles, velocity of, 3, 165.

Pronghorn, 26, ^66.

Pronouns, historical use of the rela-
tive in English literature, 43, 278.

Protococcus Nivalis, 5, 262.

Protophytes, parasitic, 21, 88.

Protoplasm, continuity of, 41, 174.

Protostega, 12, 422.

Pseudomorphs, petrifactions and al-
terations, 49, 17.

Psoas parvus and pvramidalis, 31,
117.

Pteropus, new specie? of, 28, 70.

Puerco epoch, 21, 309.

Puquina language of Peru, 28, 242.

Putnam, F. W., Key dewellers on
the Gulf Coast of Florida, 35, 438.

Pyle, Wm. Henrj*, efifect of imper-
ceptible shadows on judgment of
distance, 46, 94.

Pyrite from Cornwall, Pennsyl-
vania, 45, 131.

— and marcasite, behavior of, 33,
225.

Pyrophyllite from Schuylkill Co.,
Pa., 18, 279.

Pythonomorpha, in the Cretaceous
strata of Kansas, 12, 264.

Quartz pebble, found in a coal bed,
21, 343-

Quartzose rocks of the lower Sus-
quehanna, fossil forms in, 18,
277.

Quaternion group, 37, 312.

Queensland aborigines, divisions of,

37, 327-

Quinnimont coal group, 19, 498.

Quito, Ecuador, thermometrical ob-
servations in, 21, 676.

Radiation and rotation, 17, 701.

— solar constant of, 50, 235.
Radioactivity, 50, S33-

Radium in an American ore, 43, 157.
Railway under the English Channel,

survey for, 17, 283.
Rainbows, four, 10, 148, 149.
Rainfall, cyclical, 12, 178, 523; 14,

195-

— European and American, 12, 38.

— Jupiter-cyclical, 14, 193.

— lunar influences on, 10, 436; 12,
558; 14, 416.

— monthly, il, 314; 12, 555.

— tidal, 10, 523; II, 202."

— yearly, in the U. S., 14, 613.
Rain guage, 2, 164.

curves, 11, 113.

Rana, synonymic list of North
American species of Bufo and, 23,

514-
Rand, H. B., protection of oil tanks

from lightning, 19, 216.
Rand, Theodore D., obituary notice

of, 42, 10.
Randolph, Nathaniel Archer, obituary

notice of, 26, 359.
Rath, Gerhard von, and F. A. Genth,

vanadates and iodyrite from Lake

Valley, New Mexico, 22, ;i62.
Ratio, Chase-Maxwell, 22, 375.

65

RAVENEL-RINK

GENERAL INDEX

Ravencl, Mazyck P., warfare against

tuberculosis, 42, 212.
Reaction in improvement of rivers

and harbors, 42, 199.
Read, John M., obituary notice of,

14, 271.
.opinion as to the right to tax

the Society's Hall, 9, 14.
Reciprocity in trade, 23, 526.
Redfield, W. C, tides and currents

of ocean and atmosphere, 3, 86,

141, 225.
Reed, Henrv, obituary notice of, 6,

87.
Reed, H. D., and Wright, A. H.,

the vertebrates of the Cayuga

Lake Basin, N. Y., 48, 370.
Reflectors, 2, 260.
Reforesting, nature's, 18, 26.
Refraction tables, 16, 425.
Reichenbach, O., solar spots, 9, 234.
Reichert, Edward T. and Amos P.

Brown, crystallographic study of

the hemoglobins, 47, 298.
Reid, Harry Fielding, isostasy and

mountain ranges, 50, 444.

— — seismological notes, 48, 303.
Reid, J. D., carved rocks on the

Monongahela River, 12, 11.
Rejang River in Borneo, journey up,

35, 321.
Remains of the Foreigners discov-
ered in Egypt by Flinders-Petrie,

35, 56.
RenauU, M. B., Cours de Botanique

Fossile, 19, 287.
Rensselaria genus of bracliiopods in

the Hamilton group. Perry Co.,

Pa., 21, 235.
Representation, proportional, 34,

468.
Reptile, new IMosasauroid, 11, 116.

— theromorphous brain and auditory
apparatus of, of the Permian epoch,
23, 234.

Reptiles and batrachians of Grand
Cayman, 24, 273.

Reptiles (continued).

— catalogue of species of, in a col-
lection made at Pebas, upper Ama-
zon, 23, 94.

— from the Austroriparian region,
17, 63.

— West Indian, in the Museum of
Comparative Zoology at Cam-
bridge, Mass., 24, 278.

Reptilia, 11, 116, 271, 444; 12, 41;
17, 63, 176, 193, 505; 24, 44; 30,
III, 112.

— of the Triassic formation of the
Atlantic region of the U. S., 11,

444-
Reptilian foot-marks at Sharp Moun-
tain, Pa., 5, 91.

— remams from the Dakota Beds of
Colorado, 17, 193.

Reversion, new views about, 49, 196.

— of series, and its application to
the solution of numerical equa-
tions, 21, 91.

Reynell, John, obituary notice of,

7. 150-

Rhinocheilus Antonii, 23, 290.

Rhinochimsera. brain of, 47, 37.

Rhoads, Edward, obituary notice of,
42, 10.

Rhoads, James E., obituary notice
of, 34, 354-

Rhodium, fusibility of, 2, 182, 187

Rhyncophora of North America, 15,
I ; 16, 417.

Richards, Theodore William, inclu-
sion and occlusion of solvent in
crystals, 42, 28.

— • — sources of error in the determi-
nation of the atomic weight of
nitrogen. 43, 116.

Richardson, Harriet, Rocinela, 37, 8.

Richardson, Owen W., dynamical
effects of aggregates of electrons,
50, 347.

Rink, II., recent Danish explorations
in Greenland, 22, 280.

66

PROCEEDINGS, VOLS. 1-50

RITTER-ROSENG

Ritter, \\'illiam McKnight, determi-
nation of general perturbations of
the minor planets, 31, 124.

Robb, William L., Rontgen ray, 35,
32.

Roberts, Isaac, progress of astro-
nomical science, 32, 97.

Roberts, Solomon, obituary notice of
Edward ]\Iiller, 12, 323, 581.

. of Charles B. Trego, 14,

356.

steam canal boat, 4, 121.

Roberts, William JNIilnor, obituary
notice of, 20, 199.

Robinson, James Harvey, the new
history, 50, 179.

Robinson. Moncure, obituary notice
of Michael Chevalier, 19, 28.

, of Henry Seybert, 21, 241.

Rochambeau. Chateau de, 33, ;iS3-

Rocinela, new species of, with a
synopsis of the genus, 37, 8.

Rock blasting by galvanic ignition,

I. 99-

■ — carvings. Australian, 36, 195, 466.
on ]\Ionongahela River, 12, 11.

— pictures, aboriginal, in Fayette Co.,
Pa.. 21, 687.

in Lancaster Co., Pa., 10, 30.

in Queensland, 40, 57.

Rocks, exfoliation of, near Gettys-
burg, 14, 295.

— mushroom, 10, 382.

Rocky Alountain coals, 14, 358.

— — fossils. 12, 578.

— [Mountains, acoustic phenomenon
in, 13, 499.

Rogers, Austin F,, pseudomorphs,
petrifactions and alterations, 49,

17-
Rogers, Rev. E, P., improvement on

the carpenter's square, 6, 169.
Rogers, Fairman, obituary notice of

Josenh Henry, 18, 461.
Rogers, H. D., earthquake of 4th of

January, 1843, 2, 258, 267.
geological notes, 3, 181.

Rogers, Henry D. (continued).

geology of Berkshire, Mass., 2,

3-

and William B., geology of

western peninsula of Upper Can-
ada and western part of Ohio, 2,
120.

Rogers, Robert E., obituary notice
of, 23, 104.

Rogers, William Barton, obituary
notice of, 31, 254.

Rogers, W. B., and H. D., earth-
quakes, 3, 64.

■ ■ geology of western penin-
sula of L'pper Canada and western
Ohio, 2, 120.

Rollctt, Hermann, Die forscher, 32,

345-
Rolling-mill machinery, reserved

power in, 9, 228.
Rome, evolution of City of, 48, 129.
Rommel, Geo. M. and E. F. Phillips,

size of litter in Poland China

sows, 45, 245.
Runtgen ray, 35, 17.
Rosengarten, Joseph G., American

history from German Archives, 39,

129, 638.
— • — Chateau de Rochambeau, 33,

353-
Ear! of Crawford's ms. history

in the Library of the American

Philosophical Society, 42, 397.
— — -early French members of the

American Philosophical Society,

46, 87.

Franklin's Bagatelles, 40, 87.

"Franklin Papers" in the

American Philosophical Society,

42, 165.
Moreau de Saint Mery and his

French friends in the American

Philosophical Society, 50, 168.
obituary notice of Henry

Coppee. 34, 357.
, of William H. Furness,

Meiiwrial Volume, i, 9.

67

ROSENGARTEN-SADT GENERAL INDEX

Rosengartcn, Joseph G., oliituary

notice (continued).

-, of Henry C. Lea, 50, xxxii.

. of J. Sergeant Price,

Memorial J'olunie, i, 57.
, of Peter F. Rothermel,

34. 393-
, of Albert Henry Smyth,

46, i.
Paris Book Exhibition of 1894.

34. i2.
Rotation and radiation, 17, 701.

— cosmical, harmonies of, 13, 243.

— of the Earth, topography as af-
fected by the, 13,, 190.

— solar and planetary. 12, 406.
Rothermel. P. F., obituary notice of,

34. 393.

Rothrock, J. T., Bahamas and Ja-
maica, 29, 145.

forestry, on the growth of, in

Pennsylvania, 32, S3--

— — forests of Pennsylvania, 32,
332; 33, 114. 153-

-microscopic distinctions between

good and bad timber of the same
species, 20, 599.

.obituary notice of Thomas P.

James, 20, 293.

. of Eli K. Price. 23, ~,~2.

. of N. A. Randolpli, 26,

359.

Rothwell, map of the anthracite coal
basins, 11, 113.

Royce, Josiah, first principles of
theoretical science. 45, /j.

Riimker, Charles, astronomical obser-
vations, 2, 103.

— — Bremiker's comet, 4, 86.
— ■ — -comet of 1840, 2, 75.

Galle's first comet, i, 301.

, — second comet, I, 275.

Mauvais' comet, 4, 67.

— - — -observations on Astrare, &c., 4,

347-
Runic inscription at Yarmouth,
Nova Scotia, 21, 491.

Ruschenberger, William S. \V., obit-
uary notice of, 34, 361.

— ■ — -obituary notice of Robert
Bridges, 21, 427.

, of Gouverneur flmerson,

29, 60.

, of Joseph Leidy, 30, 135.

, of Robert E. Rogers. 22,

104.

. — ■ — of William PJarton Rog-
ers, 31, 254.

Russell, Henr}- N.. on the distances
of red stars, 49, 230.

Ryder, John A., energy as a factor
in organic evolution. 31, 192.

eye, ocular muscles, and lach-
rymal glands of the Shrew Mole,
28, 16.

fowl's egg. mechanical genesis

of. 31, 203.

modification of animal organ-
isms, effects of habitual use in,
26, 541.

— — obituary notice of, Mciiioriol
I'fllitine, I, I.

— — ^ sex, origin of. 28, 109.

— — -skeleton, calcification of the.
26, 550.

sweat-glands, phylogeny of the.

26, 534.

— • — ^ vertebrates, adaptive forms
and the vortex-motion of the sub-
stances of the red blood-Cf)rpuscles
of. 32, 272.

S := ax -i bx"4-cx'\ &c.. transfor-
mation of the series. 3, 138.

Sachse, Julius F., color photography.
Joly process of, 35, 119.

Horologium Achaz, 34, 21.

— • — Rontgen ray, 35, 28.

Throne of Congress. 37, 45.

Sadtler. .S. P.. chemical preparation
from a Petroleum reaction. 18,

44-

— — gases, calculation of result? in
analysis of. 17, 473.

68

PROCEEDINGS, VOLS. 1-50

SADTLER-SCUD

Sadtler, S. P. (continued).

natural gas from certain wells

in western Pennsylvania, 16, 206,

585.

petrocene, 18, 185.

petroleum and natural gas,

genesis and chemical relations of,

36, 93-

— — tartronic acid and molecular
structure of glyceric acid, 14, 615.

Safety guard, 2, 41.

St. Clairville and Bedford R. R. and

Dunnmg's Creek fossil iron ore,

13, 156.
St. John, Orestes, fossil fishes from

the Upper Coal ^ileasures of Ne-
braska, II, 431.
St. ]\Iary's Elk Co., Pa., geological

section at, 19, ^^ij.
Salicylic acid, detection of iron by,

18, -)]4.
dihalogen derivatives of, 24,

432.

— acids, mono- and dichlor-deriva-
tives of, 17, 476.

Saligenin, synthesis of, 18, 451.
Salishan texts, 34, 31.
Salts, absorption spectra of various,
in solution, 48, 194.

— amphide, 2, 219.

Saltville Valley { Va.) fault, 19, 349.

-shells from, 19, 155.

San Domingo and Panama, fossils

common to, 12, 572.

Rhodium gold, 11, 439.

San Francisco earthquake of 1906,

45, 164. 178.

— peninsula, geology of, 46, 3,
Sand dune plants of Bermuda, com-
parative leaf structure of, 47, 97.

Sanders, R. H., section of PalcTozoic
rocks, in Blair Co., Pa., 17, 349.

Sanderson, John, obituary notice of,
4, 62.

Sandstone, Kings Mill white, 20,
666.

Sandy Hook, survey of, 4, 168.

Sanscrit and English roots and ana-
logues, 7, 177.

Santa Cruz Typotheria, 47, 64.

Sargent, Charles S., journal of An-
dre Michaux, 26, i.

Saturn, zone of asteroids and the
ring of, 21, 263.

Saurians, Triassic, in Pennsylvania,
17, 231.

Saurocephalus of Harlan, 11, 608.

Saurodontidse, 11, 529.

Saving fund life insurance, 14,
148.

Schaffer, Charles, obituary notice of,
42, vii.

Schintz's gas generator, 10, 9.

Schoharie grit in middle Pennsyl-
vania, equivalent of the, 20, 534.

Schwartz, E. A., Coleoptera of Flor-
ida, 17, 353, 434.

— — , — of Michigan, 17, 593.
Science, successful pursuit of, 27,

34-

— theoretical, principles of, 45, yj.
Scott, Lewis Allaire, obituary notice

of. Memorial Volume, i, 49.

Scott, \\ . B., Agriochoerus, osteology
of, 3i, 243.

-Cope's contributions to geology,

Memorial Volume, i, 303.

mammalian fauna, from Deep

River beds of ^lontana, 31, 251.

-osteology of Agriochoerus

Leidy, 33, 243.

— • — Selenodont Artiodactyls of the
Uinta Formation, 37, jT)-

and Henry F. Osborn, verte-
brate fossils of the Uinta For-
mation, 24, 255.

Screw, on the, 9, 278.

Scudder, Samuel H.. ^lelanoplus,
36, 5

-Tertiary Tipulidae, with special

reference to those of Florissant,
Colorado, 32, 163.

69

SCULPTURE SHALES

GENERAL IXDEX

Sculpture, crystallography in, 17,
258.

— Medijeval German, in the Ger-
manic Museum of Harvard Uni-
versity, 47, 635.

Sea, depths of the, determined by

the echo, i, 39.
— • le\el, ancient, 9, 399.

— narratives of the walking on the,
46, 80.

Seaboard Oil Pipe Line, 17, 136.
Sea water, influence of, in distribu-
tion of salt marsh and estuarine
plants, 50, 457.
See, T. J. J., cause of earthquakes,
mountain formation and kindred
phenomena connected with the
physics of the Earth, 45, 274; 46,
191, 369.

cosmical evolution, 49, 207.

existence of planets about the

tlxed stars, 49, 222.

— ■ — -extension of the solar system
beyond Neptune and the connec-
tion existing between planets and
comets, 50, 266.

-new cosmogony, 50, 261.

-origin of the zone of asteroids

and on the capture of satellites,
49, 351-

past history of the Earth as in-
ferred from the mode of formation
of the solar system, 48, 119.

-physics of the Earth, 47, 157.

-secular effects of the increase

of the Sun's mass upon the mean
motions, major axes and eccen-
tricities of the orbits of the plan-
ets, 50, 269.

Seeds, persistent vitality in, 45, 5.

Seelish language, 23, 361.

Seller, Emma, obituary notice of.
29, 151-

presentation of portrait of, 29,

149.

Seismological notes, 48, 303.

Seismology, Congress memorialized
by American Philosophical Society
to establish a Bureau of, 48, xii.

Selection and separation, natural,
35, 175-

Selenophorus of the United States,

19, j-s.

Selish language 23, 361.

Sellers, Coleman, microscopic exam-
ination of fluids, 13, 180.

— - — obituary notice of Joseph Har-
rison. Jr., 14, 347.

transmission of energ}- by elec-
tricity, 38, 49.

Sellers, William, obituary notice of
George Whitney, 23, 388.

Semites and Hamites, 43, 173.

Series, reversion of, and its appli-
cation to the solution of numer-
ical equations, 21, 93.

Sermon books, mediaeval, and stories,
21, 49.

Serpentines of the central coast
ranges of California, 49, 315.

Set Griffin, note on a possible geo-
graphical meaning for the, 21, 455.

Sex, causes of change of, 5, 20.

— origin of, through cumulative in-
tegration, and the relation of sex-
uality to the genesis of species,
28, 109.

Seybert, Henry, obituar\' notice of,

21, 241.

Shadows, eff'ect of imperceptible, on

the jiidgment of distance, 46, 94.

— without penumbra, 1 7, 705.
Shaefer, P. W., boring records in

the Antliracite region, 11, 107, 235.

obituary notice of, 29, 39.

thunder storm of June 20, 1867,

10, 344.
visibility of stars in daylight

from depths of mines, 18, 179.
Shakespeare's Pericles and Apollo-

nius of Tyre. 37, 206.
Shales, Clinton and other, 21, 492.

70

PROCEEDINGS, VOLS. 1-50 SHAMAN-SMITH

Shamanism, relation of the Pentago-
nal Dodecahedron found near Mar-
ietta, Ohio, to, 36, 179, 183.

Sharon conglomerate in the Palaeo-
zoic series, 19, 198.

Sharpies. Stephen P.. inks, photo-
graphic testing of, 34, 471.

Sharpless, Isaac, Haverford College
Observatory, latitude of, 21, 78.

Sharswood, George, obituary notice
of Charles J. Ingersoll, 9, 260.

, , of Joel Jones, 7, 387.

. of Joseph Reed Ingersol!,

10, 513-

" Sh DI " (shaddai), on the Hebrew-
word, 23, 303.

Shells, fossil, from \'irginia Ter-
tiary, 3, 162.

— found by H. C. Lewis, at Salt-
ville. I9i 155-

— fresh water and land, 2, 11, 30,
81, 147, 224, 237, 241, 284; 4, 162.

— land, of the Pacific slope, 18, 282.

— turbinated. 2, 234.

Sherwood. Andrew, section of De-
vonian rocks at Palenville in the
Catskills, 17, 346.

Sherwood's discoveries in magnetism,

Shields. Charles W.. mental analysis

in science and philosophy, 27, 41.
Ships, aerial 21, 301.
Short, Charles Wilkins, obituary

notice of. 10, 171.
Shufeldt. R. W., osteology of the

cuckoos. 40, 4.

. — of the Striges. 39, 665.

. — of the woodpeckers. 39, 578.

ShuII. George Harrison, germinal

analysis through hybridization,

49, -^81.
Siamese photographs. 10, 201.

— Twins, 2, 22.
Sigillaria. 3, 149.

Signal Service Bureau, its methods,
and results, 24, 179; 26, 285.

Signals, color, regulation of, in
Marine and Naval Service, 43, 207.

Silicon, new method of procuring,
I. 175-

Silk culture in India, i, 214.

Silurian land plants in Ohio, 17, 163.

— • limestones, relation of, to crystal-
line rocks of Eastern Pa., 18,

435-
Siluro-crmbrian limestone beds in

Cumberland Co., Pa., analysis of,

17, 260.
Silver ore, 6, 155; 11, 92.
— ■ — -from Lake Superior, 11, 527.

from Pennsylvania, 17, 728.

Simpsoii, George, Eurypterids, from

coal shales, 21, 343.
Sinclair, William J., dermal bones

of Paramylodon from tiie asphal-

tum deposits of Rancho la Brea,

near Los Angeles, Cal., 49, 191.
Marsupial fauna of the Santa

Cruz Beds, 44, 72,-
-restored skeleton of Leptau-

chenia decora, 49, 196.
— • — Santa Cruz Typotheria, 47, 64.
Sinopa, osteology of, 44, 69.
Sirius, motions of Procyon and of,

4i II-'-
Skater's reel, 6, 179.
Skeleton, calcification of, 26, 550.
Skeletons found near Woodbury, 11,

310.
Skull, blindness froin congenital mal-
formation of, 41, 161.
Skulls, Australian and Maori, 11,

446.
Slade, Daniel Denison, jugal arch,

significance of the, 34, 50.
Slags, crystallized, 6, 246.
Slates, Peach Bottom, 18, z^.
Sloth at Big Bone Cave, Tennessee,

fossil, 36, T)6.
Smith. Albert H.. obituary notice of,

23, 606.

71

SMITH-SMITH

GENERAL INDEX

Smith, Aubrev H., Carex Miliaris, Smith, Edgar F., ol)ituary notice

25, 3-^0.

Smith, Edgar P., analysis of a cal-
culus found in a Deer, 18, 213.

barite, 24, 4,U-

-beryllium borate. 17, 706.

boric acid, determination of,

24. 429-

chlorine derivatives from tol-
uol, 16, 667 ; 17, 29.
— • — columbium and tantalum, 44,

(continued).

, of Sir George Gabriel

Stokes, 42, xiv.

, of Robert H. Thurstonr

42, viii.

, of H. C. Trumbull. 42^

viii.

— • — -precipitation of copper with
sodium carbonate, 17, 218.

salicylic acid, dihalogen deriva-
tives of, 24, 432.

decomposition of chroinic iron. and William Blum, cathodic

17, 216. precipitation of carbon, 46, 59.

detection of iron by salicylic and En. D. Desi, Tungsten,

acid. 18, 214. atomic mass of, 33, t,t,7.

-dichlorsalicylic acid, 17, 68. — - — and Franz F. Exner. atomic

electrolytic estimation of cad- weight of tungsten, 43, 123.

mium. 18, 46. ^ and Roy D. Hall, observations

— — gas, action of, from AsjO.-i and on columbium. 44, 177.

HNO3 upon );/-oxybenzoic acid, and L. G. Kollock. effect of sul-

25, 194. phuric acid on deposition of metals

lead solutions, electrolysis of, when using a mercury cathode and

24, 428. rotating anode, 45, 184.

;n-oxybenzoic acid, action of gas new results in electrolysis,

from AsjOa and HNO3 upon, 25, 46, 341.

IQ4. and ]\Iary E. Pennington,

new monochlordinitrophenol. atomic mass of tungsten, 33, ^,-^2.

17, 706. and Edgar T. Wherry, use of a

-obituary notice of Josiah Wil- rotating anode in the electrolytic

lard Gibbs, 42, xvi. precipitation of uranium and

■ , of James Glaisher, 42, xi. molybdenum, 45, 268.

, of William Harkncss, 42, and Thos. N. Wiley, corundum

xii. and wavellite near Allentown, Pa.,

20, 230.
Smith, George H., " Theory of the

State," 34, 173, 181.
Smith, J. Lawrence, new meteoric

iron from ^Mexico. 10, 3,^0.
Smith, James Perrin, marine fossils,
from the coal measures of Ar-
kansas, 35, 213.
— — paragenesis of the minerals in
the glaucophane-bearing rocks of
California, 45, 183.

— - — . of Charles Godfrey Le-

land. 42, xi.
, of J. Peter Lesley, 42,

xiii.
, of William Vincent ]\Ic-

Kean, 42, x.

, of Thomas G. Morton, 42,

vii.

. of Theodore D. Rand, 42,

X.

, of Edward Rhoads, 42, x.

, of Charles Schaffer, 42, Smith, R. Pearsall, L^nited States

vii. County maps, 9, 350.

PROCEEDINGS, VOLS. 1-50 SMOKY-SPITZKA

Smok}- Hill River, Kansas, expedi-
tion to, 12, 174.

Smyth, Albert Henry, obituary no-
tice of, 46, i.

, of Daniel G. Brinton,

Memorial Volume, i, 221.

— — , of Henry Phillips, Jr.,

Memorial Volume, i, 26.

Shakespeare's Pericles and

ApoUonius of Tyre, 37, 206.

Smyth Co., Va., geological struc-
ture of, 22, 114.

Snakes, genera of, 23, 479.

Snapper, alligator, fossil specimen
of, from Texas, 50, 452.

Snowden, A. Loudon, civil service
reform, 18, 559.

Snyder, Alonroe B., new method of
transiting stars, 41, 200.

Sodium carbonate and copper, pre-
cipitation of, 17, 218.

Solar activity and terrestrial mag-
netic disturbances, 49, 130.

— and planetary rotation, 12, 406.

— system beyond Neptune, extension
of, 50, 266.

ethereal influences in, 16, 496.

formation and primitive struc-
ture of, 12, 163.

— - — influence of ether on, 9, 384.

^ nebular action in, 16, 184.

oscillatory forces in, 13, 140.

Sun, apparent semi-diameter of, and
nebular origin of the terrestrial
day, 18, 380.

— eclipses, i, 132. 177; 2, 201; 3,
183; 5: 3-2-

— heat, distribution and trans-
mission of, 10, 309.

— mass, estimate of, 13, 142.

— records, 18, 224.

— spots, 9, 234.

Solitary confinement, eff'ects of, in
producing disease among the
Africans, 3, 143; Trans. Hist, and
Lit. Cojiiin., 3, 65.

Solutions, association theory of, 46,

138.
Song of the Arval Brethren, on the

Etrusco-Libyan elements in the,

30, 317-
Sorghum culture, 9, 116.
Sound, transmission of, through iron

pipes, 5, 118.

— and light, gamuts of, 13, 149.
South American native languages,

30, 45

— Australian aborigines, divisions
of, 39, 78.

phallic rites and initiation

ceremonies of, 39, 622.
Sows, inheritance in the female line

of, size of litter in Poland China,

45, 245.
Spain, resources, productions and

social condition of, 14, 301.
Speaking machine, 4, 83.
Species, elementarj-, in agriculture,

45, 149-
Specific gravity apparatus, 6, 193,

201.
Speck, Frank G., dying American

speech-echoes from Connecticut,

42, 346.
Spectra of metals, electrical, 14, 162.

— stellar, photographs of, 24, 166.
Speech-Echoes from Connecticut,

dying American, 42, 346.
Spencer, J. \\'., pre-glacial outlet of

Lake Erie, 19, 300.
Spermatogenesis of Oniscus asellus

Linn., with especial reference to

history of the chromatin. 41, /j.
Spheres, music of the, 13, 193.
Spina bifida. 4, 124.
Spirifera of L'pper Heldcrberg, lo,

246.
Spitzka, Edw. Anthony-, brains of

natives of the Andaman and Nico-

bar Islands, 47, 51.
death penalty by electricity,

47, 39-

73

SPY-GLASS-STONE

GENERAL INDEX

Spy-glass, new, 5, 41.

Squamosal bone oi the .Mammalia,
foramina of the, 18, 452.

Stanton, Timothy W., new fresh-
water MoUuscan Faunule from the
Cretaceous of [Montana, 42, 188.

Stapes, Columella and, in the North
American turtle, 17, 335.

Star, discovery of a missing, 4, 311.

— orbit of double, 2 := 518, 42, 170.
Stars, distances of red, 49, 230.

— fixed, lunar occultations of the, i,
228.

— new method of transiting, 41, 200.

— photographs of spectra of, 24,
166.

— relation of aerolites to shooting,
24, III.

— visibility of, in daylight, from
depths of mines. 18, 179.

Steam, electricity from, i, 320, 2, 3.

— non-electricity of nascent, 2, 160.
Steamboats for canals, 4, 121.
Stellwagen, Thomas C, Carthaginian

tombstone, 38, /2.

Stengel, Alfred, specific precipitins
and their medico-legal value in dis-
tinguishing human and animal
blood, 41, 407.

Sterneck, R. v., determination of
gravity by means of pendulum ap-
paratus, 32, 84.

Stevenson, John J., alleged parallel-
ism of coal-beds, 14, 283.

Canon City, Colorado, coal

field, 19, 505.

formation of coal beds. 50, i,

519.

geological reconnaissance of

Bland, Giles, Wythe and portions
of Pulaski and ^Montgomery
Counties of Virginia, 24, 61.

, — relations of the lignite

groups, 14, 447.

, — structure of Tazewell, Rus-
sell, Wise, Smyth and Washington
Counties, Virginia, 22, 114.

Stevenson, John J. (continued).
geology of West Virginia, 14,

370.
, — of Wise, Lee and Scott

Counties, Va., 19, 88, 219.
— ■ — Laramie group, near Raton,

N. M , 20, 107.
-notes respecting metamorphism.

22, 161.
Quinnimont coal group, Alercer

Co., W. Va., and Tazewell Co., of

Virginia, 19, 498.
— • — re-eroded channel-way, 19, 84.
surface geology of southwest

Pennsylvania and adjacent portions

of W. Virginia and Maryland, 18,

, — ■ — of southwest Virginia, 24,

172.
Cpper Frecport coal-bed, &c..

West Va., 19, 276.
Stevenson, Sara T., remains of the

foreigners discovered in Egypt by

Flindcrs-Petrie, 1895, now in the

]\Iuseum of the University of

Pennsylvania, 35, 56.
Stille, Charles J., obituary notice of

Horace Binney, Jr., 11, 371.
Stimuli, after-images of subliminally

colored, 47, 366.
Stokes, Alfred C, infusoria, new

fresh-water, 23, 562; 24, 244; 28,

74-

, — , — Hypotrichous, 23, 21.

■ , — notices of presumably unde-

scribed, 33, 3.38-
Stokes, Sir George Gabriel, obituary

notice of, 42, 14.
Stoll, Otto, Cakchiquel language of

Guatemala, 22, 255.
Stone, Frederick D., obituary notice

of William John Potts. Memorial

J'uliiinc, I, ^6.
Stone Age. connecting link between,

and present age, 10, 352.

pottery of, 10, 430.

— hand hammer, antique, 9, 401.

74

PROCEEDINGS, VOLS. 1-50

STONE-SUN

Stone Age (continued).

— implements in Africa and Asia, re-
cent discoveries of, 19, 63.

^of Indians of North America,

8, 265.
found near Potomac River,

31, 229.
Stones, ceremonial, used by the

Australian aborigines, 48, i, 460.
Stoney, G. Johnstone, dependence of

what apparently takes place in

Nature upon what actually occurs

in the universe of real existences,

42, 105.
Storm, effects of rain, 9, 59.
-wind, 7, 176.

— of Dec. 20, 1836, I, 195.

— of Feb. 9, 1858, 7, 176, 292.

— of Sept. 12, 1862, 9, 59.

— of Sept. 25, 1867, 10, 351.

— hail, of May 8, 1870, 11, 438.
Storms, 2, 56.

— in February, 1842, 3, 50.

— northeast, was Lewis Evans or
Benjamin Franklin the first to
recognize that our northeast
storms come from the southwest,

45, 129.
Stowell, T. B., accessory nerve in

the cat, 25. 94-

-facial nerve in the cat, 24, 8.

— • — glosso-pharyngeal nerve in the

cat, 25, 89.
hypoglossal nerve in the cat,

25, 99-

trigeminus nerve in the cat, 23,

459.

— •^- vagus nerve in the cat, 20, 123.

Strabismus, operation for. i, 273.

Straight line concept, 44, 82.

Strand plants of New Jersey, com-
parative leaf structure of, 48, ^2.

Strickland, William, obituary notice
of, 6, 28.

Striges, osteology of the, 39, 665.

Stromateidce, notes on the, 21, 664.

Strong, Theodore, analytical trigo-
nometry, 3, 49.

transformation of the series

S = ax -f bx= + ex', &c., 3, 138.

Strong, William, obituary notice of
Horace Binney, 16, i.

Strong, W. W., absorption spectra
of salts in solution, 48, 194.

Strontium, extrication of, i, 130.

Strychnia and nicotin, antagonism be-
tween, 16, 597.

Subsidences and elevations, regional,
12, 70.

Substitution group properties and
abstract groups, 49, 307.

Sugar cane, African, 9, 141.

Sulphvir Spring Vallej', x^rizona,
record of borings and of agricul-
tural experiments in, 40, 161.

Sulphuric acid, dilute as a fungicide,

45, 157-

effect of, on the deposition of

metals when using a mercury
cathode and rotating anode, 45,

255-
Sun and certain fixed stars, relative
ages of, 16, 622.

— and cross symbols, 26, 476.
^ planets, atmosphere of, 16, 12^.

— eclipse of, May 14, 1836 and Sep-
tember 18, 1838, I, 177.

of April 24, 1846, 4, 253.

of May 26, 1854, 6, 38.

— ^of Aug. 7, 1869, II, 202.
-of July 29, 1878, 18, 103.

— ■ glows, remarkable, in the falls of
1883 and 1884, 22, 213.

— repulsion by. of gaseous molecules
in tail of Halley's Comet, 50, 254.

— -rotation of, 13, 145.

Sun-spot cycle of 11.07 years, 12,

410.
period, planetary relations to,

13, 147-
Sun spots, 4, 173: 9, 234.
— • — -periodicity of, 11, 94.

SUN-THERMOMETER

GENERAL INDEX

Sun's distance, approximations to,

12, 398.

spectral estimates of, 18, 227.

— mass, secular effects of increase
of, 50, 269.

Sunlight, effects of, 3, iii.

Supreme Being, primitive names of
the, 9, 420.

Sweat-glands, phylogenj- of, 26, 534.

Sylviculture, 17, 197.

Syria, Expedition to, Princeton Uni-
versity Archaeological, 46, 182.

Syrphidas, North American, 20, 299.

Taconic system of Dr. Emmons, 9,

5-

Ta Ki, the Svastika and the Cross
in America, 26, 177.

Tafel, R. L., laws of English orthog-
raphy and pronunciation, 8, 285 ;

9. 39-

Tantalum, observations on Colunir

bium and, 44, 151.
Tapiroid hyrachyus, osteology of,

13. 212.

Tartronic acid and molecular struc-
ture of glyceric acid, 14, 615.

Tatham, William P., ohituary notice
of Frederick Graff, 28, 104.

Taxonomy of the genus Emys C.
Dumeril, 30, 40, 245.

Taylor, Alfred B., octonary numera-
tion and its application to a sys-
tem Df weights and measures, 24,
296.

Taylor, Richard C., asphaltum in
New Brunswick, 5, 241.

-geology of Cuba and Gibora,

3, 154.

obituary notice of, 5, 226.

■ Sigillaria, 3, I49-

— — ^ water spouts, 3, 136.

Taylor, W. Curtis, photography, com-
posite, 22, 360.

Tazewell, geological structure of,
and Washington Counties, Vir-
ginia, 12, 489; 22, T14.

Teeth, variations of the forms of

human, 28, 30.
Telea polyphemus, specialized cocoon

of, 41, 401.
Telegraph, duplex transmission, 6,

266.

— synchronous multiplex, 21, 326.
— • wires, effect of lightning on, 4,

259, 260.
Telegraphic operations of U. S.

Coast Survey, 5, 74.
Telephone, humming, 47, 329.
Telephonic overtones, 18, 39.
Telescope cross-hairs, 3, 102.

— Haverford refracting, 6, 227.

— International Southern, 45, 23-
Tellurium and bismuth minerals, 14,

223.
• — -and vanadium minerals, 17, 113.
Temperature, relations of, to gravity

and density, 10, 261.
Teredines, 14, 256.
Terrestrial magnetism, 4, 6^.
Tertiary strata of the Great Basin,

19, 60.
— ■ Tipulidae, with special reference

to those of Florissant, Colorado,

32, 163.
Testudinata, classitication and taxon-
omy of the, 31, 210.
• — -new, from the Kansas Chalk, 12,

308.
Tetracaulodon, remarks on genus, 2,

105.
Texas Permian, 20, 447, 645.
Thayer, Russell, aerial ships, 21, 301.
movements of troops in cities

in cases of riot or insurrection, 18,

89.
Theodosius, Disc of, 5, 125.
Thermal convection and radiation,

polarizing influences of, 9, 367.
Thermodynamics, cosmical. 14, 141.
Thermo-electro-photo-baric unit, 22,

377-
Thermometer, self-registering, 7,
295. 316.

76

PROCEEDINGS, VOLS. 1-50

THERM-TOWER

Thermometer (contimied).

— and barometer, Becker's self regis-
tering, 7, 339.

Thompson, Elihu, efficiencj- of dyna-
mo-electric machines, 18, 58.

obituar}- notice of George Fred-

ereck Barker, 50, xiii.

progress of the Isthmian Canal,

46, 124.

Thompson, Oswald, obituary notice
of, 10, 211.

Thoracic feet, discovery of, in a
carboniferous Phyllocaridan. 23,
380.

Thought as function, measurement
of, 36, 438.

— coordination of methods of ex-
pressing, as applied to the system
of Public School instruction, 18,

348.

Thoughts, ripening of, in common,
43, 148.

I'hree bodies, certain generaliza-
tions of the problem of, 48, 11 1.

Thunder storm, in Princeton, July
14, 1841, effects of a. 2, iii.

of June 20, 1867, 10, 344.

Thurston, Robert H., obituary notice
of, 42, viii.

Thyrsus of Dionysos, and the palm
inflorescence of the winged fig-
ures of Assyrian monuments, 31,
log.

Tiaporus, new genus of Teiidae, 30,
132.

Tidal ellipsoid, normal position of
the, 12, 123.

— wave, lunar, in Lake Michigan, 7,
378.

Tides and currents of ocean and at-
mosphere, 3, S6.

— component elements of normal
barometric, 9, 405.

— height of, 9, 291.

—solar and lunar magnetic and
aerial, comparison of, 9, 487.

Tilghman, Richard A., decomposing
power of water at high tempera-
tures, 4, 353.

-obituary notice of. Memorial

J'fllume, I, 189.

Timber in the far West, scarcity of,
10, 322.

— microscopic distinctions between
good and bad species, 20, 599.

examination of, with regard to

strength, 21, 333.
Timucua language, 16, 626; 17, 490;

18, 465.
Tin plates, engraving on, 6, 165.
Titaniferous iron ore belt near

Greensboro, N. C, 12, 139.
Titchener. Edw. B. and Wm. H.

Pyle, after-images of subliminally

colored stimuli, 47, 366.
• effect of imperceptible

shadows on the judgment of dis-
tance, 46, 94.
Tittmann, O. H., the demarkation of

the Alaska boundary, 47, 86.
Tlingit, Ilaida, etc., languages, 29,

Toads, explanation of reported
showers of, 43, 163.

Toltecs, were the, an historic nation-
ality?, 24, 229.

Tombstone, Carthaginian, 38, 72.

Tomiopsis, on the genus, 31, 317.

Tonka wa language, 16, 318.

Tooth, on the trituberculate type of
molar, in the ]\Iammalia, 21, 324.

Topography as affected by the rota-
tion of the Earth, 13, 190.

Tornado of August, 1838, i, 58.

— August 5, 1843. 4. 12.

— May II, 1865, 10, 108.
Tornadoes, electrical origin of, i,

122.
Torques, African, 5, 202.
Tortoises. Cretaceous, 11, 16, 515.
Tower of the New Public Buildings

in Philadelphia, 16, 337.

TOXODON-TUCKER

GENERAL INDEX

Toxodon, structure of the posterior

foot of, 19, 402.
Trade, is tliere rcciprocit\- in ?, aud

the consumption of manufactured

commodities, 23, 526.

— tokens, circulating during the War
of the Rebellion, 9, 242.

Trades monsoon area, enquiry into

the pressure and rainfall conditions

of the, 44, 159.
Transformation of the series S =

ax -|-bx" +cx", &c.. 3, 138.
Transit, Heller and Brightly's new,

12, 115.

— instrument, method of replacing
cross hairs in telescope of, 3, 102.

— level, new, 10, 288.
Transitive Substitution Groups that

are simply isomorphic to the Sym-
metric or the Alternating Group
of Degree Six, 36, 2aS.

Transportation in the United States,
46, 171.

Trap at Williamson's Point, 18, 96.

— dyke, across southeastern Pennsyl-
vania, 22, 438.

— dykes in the Arclijean Rocks of
southeastern Pennsylvania, 21, 691.

Traps of the Mesozoic Sandstone in
York and Adams Counties,. 14,
402.

— on the Mesozoic red Sandstone of
Pa. and Connecticut, microscopical
sections of, 14, 430, 431.

Travis, Charles, pyritc from Corn-
wall, Pennsylvania, 45, 131.
Treasury note, Turkish, 6, 214.
Trees, fruit, revival of, 12, 3.

— for the Park, circular relative to,
16, 340.

Trego, C. B., Disc of Theodosius, 5,

125.
Indian Walk of 1737, 5, 127.

— • — obituary notice of, 14, 356.-
, of Don Lucas Alaman, 5,

336.
seventeen-year locusts, 5, 209.

Trelease. William, desert group No-
line;e, 50, 405.

— • — -species in Agave, 49, 231.

Trial by jury, 9, 209.

Triangles, (prime) right-angled, and
V2, 9, 415.

Trias, important Ijoring through
2000 feet of, in eastern Pennsyl-
vania, 29, 20.

— of North America, vertebrata of,
24, 209.

Triassic Mammals, Dromatherium
and Microconodon, 24, 109.

— plants of North Carolina found in
Pennsylvania, 19, 16.

— Saurians in Pennsylvania, 17, 231.
Tribal names, Indian, 23, 294.
Trigeminus nerve, in the cat, 23,

459-
Trigonometry, analytical, 3, 49.
Trionychidse, existing genera of the,

42, 268.
Trippel, Alexander, Schintz's gas

generator, 10, 9.
Troops, mo\'ements of, in cities in

cases of riot or insurrection, 18,

89.
Trowbridge, Augustus, ether drift,

49, 52.

Trowliridge, r)a\id, atmosphere of
the Sun and planets, 16, Z-1 ■

Trowbridge, John, spectra of gases
at high temperatures, 41, 138.

Troyon, I'^'ed, Merovingian grave-
yard, 10, 3.

True, Frederick W., classilication of
the Cctacr;i, 47, ,-^85.

Trumbull, I kiiry Clay, obituary no-
tice of, 42, viii.

Truss, bridge, depth and stiffness,

44. 164-

Trusts, problem of, 42, 15.

Tuberculosis in animals, ^Zi i53-

— -warfare against, 42, 212.

Tucker, George, effect of gold mines
of California upon the value of
the precious metals, 5, 148.

PROCEEDINGS. VOLS. 1-50 TUCKER-VELOCITY

Tucker, George (continued).

-obituary notice of, 9, 64.

— • — • Siamese Twins, 2, 22.
'lumor and tissue growth, 47, 3.
Tungsten, atomic mass of, 33, 332,

337-
—, — weight of, 43, 123.
Tunnel, construction of Hudson and

Manhattan Raih-oad Co.'s, 49, 164.
Turbine of Fourneyron, 3, 169.

— Curtis steam, 42, 68.

Turtles, cohunella and stapes in some

North American, 17, 335.
Tutelo tribe and language, 21, i.
Twins, Siamese, 2, 22.
Tyler, Lyon G., science expunges

error, 27, 34.
Typotheria. Santa Cruz, 47, 64.
Tyson, Job R., obituary notice of

William Peter, 6, 115.
-social and intellectual state of

Pennsylvania prior to 1743, 3, 118;

Trans. Hist, and Lit. Conini., 3,

41-

— Philip 'V ., Cumberland coal basin,

II, 9-

LHiler. P. R., Albirupean formation,
and its nearest relatives in Mary-
land. 25, 42.

Uinta formation, vertebrate fossils
of the. 24, 255.

L'ngulata, short footed, from the
Wyoming Eocene, 13, 38.

LTngulate mammalia, classification
of, 20, 438.

L^nit, thermo-electro-photo-baric, 22,

377-

L^nited States Coast Survey, tele-
graphic operations of the, 5, 51, 74.

physical geography of, 16, 61.

Units, metric and English, tables for,
17, 5.36.

Universe of real existences, 42, 105.

LTniversities and the learned societies,
alliance of the, 18, 536.

LTniversity Extension Teaching, ob-
jectionable, 29, 50.

L^pper Freeport coal bed, 19, 276.

Upson, Walter L., humming tele-
phone, 47, 329.

Upthrow fault at Embreville Fur-
nace, E. Tennessee, 12, 444.

L'ranu'^. perturbations of, by Nep-
tune, 5, 15.

Vaccine virus, deterioration of, I,

68.
Vagus nerve of cat, 20, 123.
Vail, Hugh D., Mount Vesuvius, 10,

421, 4-'5-
Valentini, Mexican Calendar Stone,

14, 663.
Valves, new form of, 6, 243.
Vanadates and iodyrite from Lake

Valley, New Mexico, 22, 363.
Vanadium, 17, 113.

— atomic weight of, 50, igi.

\'an Denburgh, John, herpetological
notes, 37, I39-

-notes on some birds of Santa

Clara County, California, 38, 157.

Van't Hoff, Jacobus Henricus, obitu-
ary notice of, 50, iii.

Variation, organic, 24, 113.

Vaux, Richard, obituary notice of
Franklin B. Gowcn, 28, 61.

, of James R. Ludlow, 24,

19.

, of H. M. Phillips, 22, 72.

prison system of Pennsylvania,

21, 651.

— ■ — Sun and Cross symbols, 26, 476.

— Wm. S., obituary notice of, 22,
404.

Vegetation, effect of floods upon, 50,
118.

Velocity effects, elimination of, in
measuring pressures in a fluid
stream, 45, 77.

■ — ^ of projectiles, new method of de-
termining, 3, 165.

7^

VENTIL-WALKER

GENERAL IXDEX

Ventilation, health and, lo, 8.

— system of passenger car, 43, 247.
Venus, transit of, 14, 423.

at Nagasaki, 14, 423.

Vera Cruz, relics from, 11, 83.

Verb in American languages, 22, 332.

Vertebrata, 12, ^68, 210, 460, 466,
469, 483, 487, 554; 14, 361; 17, .u,
52, 182, 219, 233, 268; 19, 27, 38,
195; 20, 139, 447, 461, 478; 24,
209; 30, 123, 221, 278, 282; 36, 71.

— from Upper Tertiary, Formations
of the West, 17, 219.

— new Paleozoic, from Illinois, Ohio
and Pennsylvania, 36, 71.

— of the Dakota Epoch of Colorado,
17, 233.

— of the Permian Formation of
Texas, 19, 38: 20, 447.

— of the Pucrco Eocene Epoch, 20,
461, 545-

— of the Trias of North America,
24, 209.

— phylogeny of the, 30, 2/8.
Vertebrate fossils of the Uinta For-
mation, 24, 255.

— palc-eontology of Brazil, 23, r.

— — of Texas, 30, 123.
Vertebrates, adaptive forms of the

vortex-motion of the substances of
red blood-corpuscles of, 32, 2/2.

— descriptions of some, of the Car-
boniferous Age, 39, 96.

— of the Cayuga Lake Basin, N. Y.,
48, 370.

— some new Palaeozoic, 30, 221.

— some points in the kinetogenesis
of the limbs of, 30, 282, 305.

Vesuvius, 10, 421, 425.

Vibrations, caused by heat, 6, ^2.

Victoria, native tribes of. their lan-
guages and customs. 43, 54.

Virginia, geology of various counties
of, 19, 88, 219; 22, 1 14.

— southern, coal system of, 9, 30.

— southwest, geology of, 24, 172.

Vivisection of the brain of a pigeon,

17, 3I4-
Vocabularies, Copto-Egyptian, 10, 65.

— from the Musquito Coast, 29, i.

— of the Seelish language, 23, 367.

— two unclassified rec.ent. from
South America. 37, 321.

Volapiik, 24, 415, 421. 436; 25, 3, 13,
312.

Vowel sounds, not used in any lan-
guage. 9, 271.

Vries, Hugo de, elementary species
in agriculture. 45, 149.

Wagner Institute of Philadelphia.

some of the work of, 32, 245.
Waitshum'ni dialect of the Kawi'a

language. 23, 372.
Wake. C. Staniland, Malay language,

Asiatic affinities of the, 28, 81.
Walker, Sears C. analogy of periods

of rotation of primary planets, 5,

97-

August meteors, i, 261.

■ Biela comets, 4, 235.

— — -comet of 1843, 3, 67.

— ■ — discovery of a missing star, 4,

311-
elements of the planet Neptune,

4. 332, 339-

• Encke's comet, 2, 186.

ephcmeris of the planet Nep-
tune, 5, 20.

Erlel meridian circle, 4, 113.

longitudes from observations of

meteors, i, 161.

. — in southern Michigan, i, 7.

lunar occultations of the fixed

stars, I, 71. 22i^.

— — mirage, lateral and vertical, i,
188.

obituary notice of E. R. Mason,

2, 7-
— • — periodical meteors, 2, 18.
— • — ^ telegraphic operations of the U.

5. Coast Survey, 5, 74.

80

PROCEEDINGS. VOLS. i-;o

WALK WHERRY

Walking on the sea, narratives of the,

46, 80.
Wall, J. Sutton, Indian picture rocks

in Fayette County, Pennsylvania,

21, 687.

Walter, Thomas U., foundation of
great tower of New Puhlic Build-
ings in Philadelphia, 16, 337.

obituary notice of, 25, 322.

Warwick, Hill Sloane, formates, the
electrolysis of metallic, 29, 103.

Washington County, Va., geology of,

22, 114.

— -Observatory, history of, and in-
struments ordered for, 3, 85.

Water at high temperatures, decom-
posing power of, 4, 353.

— flow of, through an opening in a
pierced plate, 16, 310; 17, 124.

— measurement of the action of,
upon metals, 46, no.

— polarization of, 4, 229.

— • sterilization of city, 29, 26.
— ■ supplies, purihcation of, by hypo-
chlorites, 48, 67.
Waterfall sensitive to human voice,

12. 515-
Water spouts, 3, 134, 136.
Waterloo, descriptive list of medals

struck to commemorate battle of,

18, 78.
Waterways, emancipation of the, 44,

42.

— The Nation and the, 48, 51.
Wave interference, results of, 17,

294.
Waves, electric, propagation of long,
along wires, 49, 364.

— gravitating, 14, 344.

— kinetic ratio of sound to light, 18,

4^5-
Wayne, Henry C, introduction of

the camel into the United States,

6, 275.
Weather forecast, experiment in, 22,

207.

— lunar influence upon, 5, 117.

— notes, American, 12, 40.

— study, 13, 248.

Weedon, George, Brig.-Genl., calen-
dar of the correspondence of, 38,
81.

Weights and measures and balances,
standard, 4, 159.

— standard, French and American,

4, 155-

Well, spouting water, at Wilcox, Pa.,
17, 127.

West Indian Islands, physical geog-
raphy and geology of, 12, 56.

— terrestrial ^lollusca in, 12,

56.
Reptiles in the ^luseum of

Comparative Zoology at Cam-
bridge, ]\Iass., 24, 278.
West Indies, physical geography of,

12, 56.
West Virginia, geology of, 14, 370,

19, 438, 498.
Western Australia, aborigines of, 39,

123: 44, 3^; 46, 361.
Wetherill, Charles M., deterioration

of ether by age, 9, 171.
examination of an exploded

locomotive, 14, 264.

— — gold in Pennsylvania, 5, 274.
neutral sulphate of oxide of, 5,

3,5-
Wetherill. John Price, oliituary notice

of, 6, 14.
Whale, Jonah's, 46, 151.
Wharton, Joseph, Krakatoa, eruption

of 1883, dust from the, 32, 343.

— — obituary notice of, 48, Ixxi.
palladium, 43, 332.

— — Rontgen ray, remarks on, 35,

31-

Wheat worm, 5, 162.

Wherry, Edgar T., rotating anode in
the electrolytic precipitation of
uranium and molybdenum, 45, 268.

81

WHIPPLE -WOODPECK GENERAL INDEX

\\'hipi)lc, S. II., mastodon Ijones, 4,

35-
White, I. C, geology of tlie Cheat

River Canon, 20, 479.
, — of West Virginia, 19, 438;

20, 479-
— • — Sharon conglomerate in the Pal-

?eozoic series, 19, igS.
Whitehead, J. B., high voltage corona

in air, 50, 374.
Whitney George, obitnary notice of,

23, 388.
Wilcocks, Alexander, inflnence of the

ether on solar system, 9, 384.
• — ■ — -shadows without penumbra, 17,

705.

Wilder, Burt G., brain of about one-
half the average weight from an
intelligent white man, 49, 188.

, — of the cat, 19, 524.

, — of Rhinochim?era, 47, 2>7-

Wiley, Harvey W., effect of preser-
vatives on metabolism, 44, 66; 47,
302.

— — and Herman Schreiber, produc-
tion of synthetic alcohol, 46, 117.

Wiley, Thomas N., corundum and
wavcllite near Allentown, Pa., 20,
230.

Wilkes Land, why America should
re-explore, 48, 34.

Willcox, Joseph, some of the work
of the Wagner Free Institute of
Science of Philadelphia, 32, 245.

Williams. Edward 11., Jr., Kansan
drift in Pennsylvania. 37, 84.

Williams, Henry S., crinoid with
movable spines, 21, 81.

Williams 1"alcott, centennial anni-
versary of the death of Benjamin
Franklin, 28, 162, 172, 176, 198,
207, 225.

Williamson, R. S.. meteorological
observations on the Nile in 1873,
14, 632.

Williston, S. W., North American
Syr]ihidcT, 20, 299.

Wilson, Sir Daniel, research into the
Ijook of nature has not discovered
an erratum, 27, 27.

Wilson, Harold A., constitution of
the atom, 50, 366.

Wilson, J. C, osteitis deformans, 41,

143-

Wilson, Joseph Miller, obituary no-
tice of, 42, I.

, of Thomas U. Walter, 25,

322.

Winchell. A., geological age of the
Marshall group, 11, 57, 245, 385,

Winds of Europe, 12, 123.

— of United States, 12, 65.

Winged figures of Assyrian monu-
ments, the Thyrsos of Dionysos
and the palm inflorescence of the,
31. J09.

Winnebago language, 10, 389.
Wise County, Va., geology of, 22,

114.
Wistar, Isaac J., obituary notice of

Richard A. Tilghman, lircmorial

I'oluiiic, I, 189.
Wister, Caspar, ALD., obituary notice

of, 26, 492.
Witcbcr.'ift talcs, some Passama-

quoddy, 38, 181.
Wood, George B., address, 7, 331.
-Indian relics from New Jersey,

11, 213, 283.

— — influence of fresh wood ashes
on the growth of wheat, potatoes,

&C., 12, 32T,.

■ -obituary notice of. 19, 118.

, of Franklin Bache, 10,

121.
— • — revival of fruit trees, II, 237;

12, 3-

— Horatio C, fresh water algre of
eastern North America, 11, 119.

-medical activity of N. American

hemp, II, 226.
— - — Oedogonium Huntii, 10, 23i3-
Woodpeckers, osteology of the, 39,

^^78.

82

PROCEEDINGS, VOLS. 1-50

WOODS-ZONE

Woods, microscopic distinctions be-
tween good and bad of same spe-
cies, 20, 599.

Wool, Saxony. 5, 259.

Wootten, J. E., apparatus to consume
anthracite coal waste, 16, 214.

Words, insensible gradation of, 7,
129.

Worm in a horse's eye, i, 200.

Wright, Albert H., vertebrates of the
Cayuga Lake Basin, N. Y., 48, 370.

— • Fred Eugene, crystallographic
properties, 42, 237.

Writing, ikonomatic method of pho-
netic, with special reference to
American Archaeology. 23, 503.

— illuminative, among Pennsylvania
Germans, 36, 424.

Wyandots, phonology of the, 4, 268.
Wyckoft, A. B., oil, in storms at sea,

23, 383-
Wyoming and Colorado, geology of,
10, 463; II, 15, 431.

— Eocene, claw-footed carnivora of,
13, 198.

— Fishes of tertiary shales of Green
River, 11, 380.

• Pleurodora from, 12, 472.

short-footed Ungulates from,

13, 38.
vertebrata from, 12, 460, 469,

483. 487.
Wythe County, Va., geological rec-
onnaissance of, 24, 61.

X-ray, new physical phenomena of
the, 35, 298.

Xinca Indians of Guatemala, lan-
guage and ethnologic position of
the, 22, 8g.

Yardley fault. 34, 381.

Yellow and ^ilissouri Rivers, geology

of, II, 112.
Yolk nucleus in Cymatogastcr aggre-

gatus, 31, 358: 33, 74.
York County, Pennsylvania, geology

of, 23, 391.

• Limonites of, 14, 364.

traps of, 14, 4J2.

Z, notes on letter. 21, 330; 22, 275.

Zacualtipan coal deposits, 23, 146.

Zantedeschi, Fran., dew and hoar
frost, 9, 456-

— — duplex transmission in teleg-
raphy, 6, 267.

-measure of the limits of the

electric nervo-muscular sensibility
in Man, compared with his me-
chanical force, 6, 291. 295.

— - — photography, &c., 9, 281. ;^/2.

— • — polarized light of comets, 6,

Zentmayer, Joseph, obituary notice

of, 3i» 358.
Zircon, 5, 273; 16, 518.
Zone of asteroids and the ring of

Saturn, 21, 263.

Ili"

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