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387TH CONGRESS, \ SENATE. { Mis. Doc.

3d Session.

ANNUAL REPORT

OF

THE BCARD OF REGENTS

OF THE

SMITHSONTAN INSTITUTION,

SHOWING TILE

OPERATIONS, EXPENDITURES, AND CONDITION OF
THE INSTITUTION FOR THE YEAR 1862.

WAS DING TON:
GOVERNMENT PRINTING OFFICE.
1863.

In Tue Senate or THE Unirep States, February 28, 1863.

Resolved, That five thousand additional copies of the Report of the Smithsonian Institu-
tion for 1862 be printed—two thousand for the use of the Smithsonian Institution, and
three thousand for the use of the Senate; Provided, That the aggregate number of pages
contained in said report shall not exceed four hundred and fifty, without wood-cuts or p'ates,
except those furnished by the Institution; and that the Superintendent of the Public
Printing be authorized, if consistent with the public service, to allow the Smithsonian
Institution to stereotype the report at its own expense, or to otherwise print at its own
expense such additional copies as may be desired from the type set in the Government

Printing Establishment.

LETTER

OF THE

SECRETARY OF THE SMITHSONIAN INSTITUTION,

TRANSMITTING

ANNUAL REPORT OF THE BOARD OF REGENTS.

SMITHSONIAN INSTITUTION,
Washington, February 19, 1863.
Sir: In behalf of the Board of Regents, I have the honor to sub-
mit to the House of Representatives of the United States the annual
report of the operations, expenditures, and condition of the Smith-
sonian Institution for the year 1862.
I have the honor to be, very respectfully, your obedient servant,
JOSEPH HENRY,
Secretary Smithsonian Institution.
Hon. HannipaL Hamuiin,
Vice President of the United States and President of the Senate.

ANNUAL REPORT OF THE BOARD OF REGENTS

OF THE

SMITHSONIAN INSTITUTION,

SHOWING

THE OPERATIONS, EXPENDITURES, AND CONDITION OF THE INSTI-
TUTION UP TO JANUARY, 1863, AND THE PROCEEDINGS
OF THE BOARD UP TO FEBRUARY, 1863.

To the Senate and House of Representatives :

In obedience to the act of Congress of August 10, 1846, establish-
ing the Smithsonian Institution, the undersigned, in behalf of the
Regents, submit to Congress, as a report of the operations, expendi-
tures, and condition of the Institution, the following documents:

1. The Annual Report of the Secretary, giving an account of the
operations of the Institution during the year 1862.

2. Report of the Executive Committee, giving a general statement
of the proceeds and disposition of the Smithsonian fund, and also an
account of the expenditures for the year 1862.

3. Proceedings of the Board of Regents up to February 4, 1863.

4, Appendix.

Respectfully submitted.
R. B. TANEY, Chancellor.
JOSEPH HENRY, Secretary.

OFFICERS OF THE SMITHSONIAN INSTITUTION.

ABRAHAM LINCOLN, £x officio Presiding Officer of the Institution.
ROGER B. TANEY, Chancellor of the Institution.

JOSEPH HENRY, Secretary of the Institution.
SPENCER F. BAIRD, Assistant Secretary.

W. W. SEATON, Treasurer.

WILLIAM J. RHEES, Chief Clerk.

A. D. BACHE, 7}
JOSEPH G. TOTTEN, \ Executive Committee.
R. WALLACH. J

REGENTS Of PRE INS LET ULILON:,

H. HAMLIN, Vice-President of the United States.

ROGER B. TANEY, Chief Justice of the United States.

R. WALLACH, Mayor of the City of Washington.

W. P. FESSENDEN, member of the Senate of the United States.
L. TRUMBULL, member of the Senate of the United States.
GARRETI DAVIS, member of the Senate of the United States.
S. COLFAX, member of the House of Representatives.

E. McPHERSON, member of the House of Representatives.

S. 8S. COX, member of the House of Representatives.

W. B. ASTOR, citizen of New York.

W.L. DAYTON, citizen of New Jersey.

T. D. WOOLSEY, citizen of Connecticut.

ALEXANDER D. BACHE, citizen of Washington.

JOSEPH G. TOTTEN, citizen of Washington.

LOUIS AGASSIZ, citizen of Massachusetts.

MEMBERS EX OFFICIO OF THE INSTITUTION.

ABRAHAM LINCOLN, President of the United States.
HANNIBAL HAMLIN, Vice-President of the United States,
W. H. SEWARD, Secretary of State.

S. P. CHASH, Secretary of the Treasury.

E. M. STANTON, Secretary of War.

G. WELLES, Secretary of the Navy.

M. BLAIR, Postmaster General.

EK. BATES, Attorney General.

ROGER B. TANEY, Chief Justice of the United States.
D. P. HOLLOWAY, Commissioner of Patents.

RICHARD WALLACH, Mayor of the City of Washington.

HONORARY MEMBERS.

BENJAMIN SILLIMAN, of Connecticut.
A. B. LONGSTREET, of Mississippi.
CALEB B. SMITH, Secretary of the Interior, (¢x officio.)

PROGRAMME OF ORGANIZATION

OF TUE

SMITHSONIAN INSTITUTION,

[PRESENTED IN THE FIRST ANNUAL REPORT OF THE SECRETARY, AND
ADOPTED BY THE BOARD OF REGENTS, DECEMBER 13, 1847.]
6

INTRODUCTION.

General considerations which should serve as a guide in adopting a Plan
of Organization.

1. Witt or Smituson. The property is bequeathed to the United
States of America, “to found at Washington, under the name of the
SMITHSONIAN INSTITUTION, an establishment for the increase and dif-
fusion of knowledge among men.”’

2. The bequest is for the benefit of mankind. The government of
the United States is merely a trustee to carry out the design of the
testator.

3. The Institution is not a national establishment, as is frequently
supposed, but the establishment of an individual, and is to bear and

erpetuate his name.

4, The objects of the Institution are, Ist, to increase, and 2d, to
diffuse knowledge among men.

5. These two objects should not be confounded with one another.
The first is to enlarge the existing stock of knowledge by the addition
of new truths; and the second, to disseminate knowledge, thus in-
creased, among men.

6. The will makes no restriction in favor of any particular kind of
knowledge; hence all branches are entitled to a share of attention.

T. Knowledge can be increased by different methods of facilitating
and promoting the discovery of new truths; and can be most exten-
sively diffused among men by means of the press.

8. To effect the greatest amount of good, the organization should
be such as to enable the institution to produce results, in the way of
increasing and diffusing knowledge, which cannot be produced either
at all or so efficiently by the existing institutions in our country.

9. The organization should also be such as can be adopted provi-
sionally; can be easily reduced to practice, receive modifications, or
be abandoned, in whole or in part, without a sacrifice of the funds.

10. In order to compensate, in some measure, for the loss of time
occasioned by the delay of eight years in establishing the Institution,
a considerable portion of the interest which has acerued should be
added to the principal.

8 PROGRAMME OF ORGANIZATION.

11. In proportion to the wide field of knowledge to be cultivated,
the funds are small. Economy should therefore be consulted in the
construction of the building; and not only the first cost of the edifice
should be considered, but also the continual expense of keeping it in
repair, and of the support of the establishment necessarily connected
with it. There should also be but few individuals permanently sup-
ported by the Institution.

12. The plan and dimensions of the building should be determined
by the plan of organization, and not the converse.

13. It should be recollected that mankind in general are to be ben-
efited by the bequest, and that, therefore, all unnecessary expendi-
ture on local objects would be a perversion of the trust.

14. Besides the foregoing considerations deduced immediately from
the will of Smithson, regard must be had to certain requirements of
the act of Congress establishing the Institution. These are, a library,
aimuseum, and a gallery of art, with a building on a liberal scale to
contain them.

SECTION I.

Plan of Organization of the Institution in accordance with the foregoing
deductions from the will of Smithson.

To Increase Know ence. It is proposed—

1. To stimulate men of talent to make original researches, by offer-
ing suitable rewards for memoirs containing new truths; and

2. To appropriate annually a portion of the income for particular
researches, under the direction of suitable persons.

To Dirruse KnowLepcGe. It is proposed—

1. To publish a series of periodical reports on the progress of the
different branches of knowledge; and

2. To publish occasionally separate treatises on subjects of general
interest.

DETAILS OF THE PLAN TO INCREASE KNOWLEDGE.
I.—By stimulating researches.

1. Facilities to be afforded for the production of original memoirs
on all branches of knowledge.

2. The memoirs thus obtained to be published in a series of vol-
umes, in a quarto form, and entitled Smithsonian Contributions to
Knowledge.

3. No memoir on subjects of physical science to be accepted for
publication which does not furnish a positive addition to human
knowledge, resting on original research; and all unverified specula-
tions to be rejected.

4. Each memoir presented to the Institution to be submitted for
examination to a commission of persons of reputation for learning in

PROGRAMME OF ORGANIZATION. 9

the branch to which the memcir pertains; and to be accepted for pub-
lication only in case the report of this commission be favorable.

5. The commission to be chosen by the officers of the Institution,
and the name of the author, as far as practicable, concealed, unless
a favorable decision be made.

6. The volumes of the memoirs to be exchanged for the transac-
tions of literary and scientific societies, and copies to be given to all
the colleges and principal libraries in this country. One Pe of the
remaining copies may be offered for sale; and the other carefully pre-
served, to form complete sets of the work, to supply the demand
from new institutions. .

7. An abstract, or popular account, of the contents of these me-
moirs to be given to the public through the annual report of the
Regents to Congress.

IIl.— Ly appropriating a part of the income. annually, to special objects
of research, under the direction of suitable persons.

1. The objects, and the amount appropriated, to be recommended
by counsellors of the Institution.

2. Appropriations in different years to different obje ae so that,
in course of time, each branch of knowledge may receive a share.

3. The results obtained from these appropriations to be Salen
with the memoirs before mentioned, in the volumes of the Smithso-
nian Contributions to Knowledge.

4. Examples of objects for which appropriations may be made.

(1.) System of extended meteorological observations for solving the
problem of American storms.

(2.) Explorations in descriptive natural history, and geological,
magnetical, and topographical surveys, to collect materials for the
formation of a Physical Atlas of the United States.

(3.) Solution of experimental problems, such as a new determina-
tion of the weight of the earth, of the velocity of electricity, and
of light; chemical analyses of soils and plants ; collection and publi-
cation of scientific facts accumulated in the oflices of government.

(4.) Institution of statistical inquiries with reference to physical,
moral, and political subjects.

(5.) Historical researches and accurate surveys of places celebrated
in American history.

(6.) Ethnological researches, particularly with reference to the dif-
ferent races of men in North America ; also, explorations and accurate
surveys of the mounds and other remains of the ancient people of
our country.

DETAILS OF THE PLAN FOR DIFFUSING KNOWLEDGE.

I.— By the publication of a series of reports, giving an account of the new
discoveries in science, and of the changes made from year to year in all
branches of knowledge not strictly professional.

1. These reports will diffuse a kind of knowledge generally inter-
esting, but which, at present, is inaccessible to the public. Some of

10 PROGRAMME OF ORGANIZATION.

the reports may be published annually, others at longer intervals, as
the income of the Institution or the changes in the branches of
knowledge may indicate.

2. The reports are to be prepared by collaborators eminent in the
different branches of knowledge.

3. Each collaborator to be furnished with the journals and publi-
cations, domestic and foreign, necessary to the compilation of his
report; to be paid a certain sum for his labors, and to be named on
the title-page of the report.

4. The reports to be published in separate parts, so that persons
interested in a particular branch can procure the parts relating to it
without purchasing the whole.

5. These reports may be presented to Congress for partial distri-
bution, the remaining copies to be given to literary and scientific in-
stitutions, and sold to individuals for a moderate price.

The following are some of the subjects which may be embraced in
the reports:
I, PHYSICAL CLASS.

1. Physics, including astronomy, natural philosophy, chemistry,
and meteorology.

2. Natural history, including botany, zoology, geology, &c.

3. Agriculture.

4, Application of science to art.

II. MORAL AND POLITICAL CLASS.

5. Ethnology, including particular history, comparative philology,
antiquities, &c.

6. Statistics and political economy.

7. Mental and moral philosophy.

8. A survey of the political events of the world, penal reform, &c.

III. LITERATURE AND THE FINE ARTS.

9. Modern literature.
10. The fine arts, and their application to the useful arts.
11. Bibliography.

12. Obituary notices of distinguished individuals.

Il.—By the publication of separate treatises on subjects of general interest.

1. These treatises may occasionally consist of valuable memoirs
translated from foreign languages, or of articles prepared under the
direction of the Institution, or procured by offering premiums for the
best exposition of a given subject.

9. The treatises should, in all cases, be submitted to a commission
of competent judges previous to their publication.

3. As examples of these treatises, expositions may be obtained of

PROGRAMME OF ORGANIZATION. 17

the present state of the several branches of knowledge mentioned in
the table of reports.

SECTION II.

Plan of organization, in accordance with the terms of the resolutions of
the Board of Regents providing for the two modes of increasing and
diffusing knowledge.

1. The act of Congress establishing the Institution contemplated
the formation of a librar ry and a museum; and the Board of Regents,
including these objects in the plan of organization, resolved to divide
the income* into two equal parts.

2. One part to be appropriated to increase and diffuse knowledge
by means of publications and researches, agreeably to the scheme
before given. The other part to be appropriated to the formation of
a library and a collection of objects of nature and of art.

These two plans are not incompatible one with another.

4. To carry out the plan before described, « library will be required,
consisting, first, of a complete collection of the transactions and pro-
ceedings of all the learned societies in the w: rld; second, of the more
important current periodical publications, aid other works necessary
in preparing the periodical reports.

5. The Institution should make special collections, particularly of
objects to illustrate and verify its own publications.

6. Also, a collection of instruments of research in all branches of
experimental science.

7. With reference to the collection of books, other than those men-
tioned above, catalogues of all the different libraries in the United
States should be procured, in order that the valuable books first pur-
chased may be such as are not to be found in the United States.

8. Also, catalogues of memoirs, and of books and other materials,
should be collected for roudering the Institution a centre of biblio-
graphical knowledge, whence the student may be directed to any.
work which he may require.

9. It is believed that the collections in natural history will increase
by donation as rapidly as the income of the Institution can make pro-
vision for their reception, and, therefore, it will seldom be necessary
to purchase articles of this kind.

10. Attempts should be made to procure for the gallery of art casts
of the most celebrated articles of ancient and modern sculpture.

11. The arts may be encouraged by providing a room, free of ex-
pense, for the exhibition of the objects of the Art-Union and other
similar societies.

12. A small appropriatiow should annually be made for models of
antiquities, such as those of the remains of ancient temples, &c.

* The amount of the Smithsonian bequest received into the Treasury of the

Wimitedy States ss 2. oat a stews anaes 6 aoc onmceemmeoasiaem sate we sicuue $515,169 00
Interest on the same to July 1, 1846, (devoted to the erection of the build-
ING) pee Cee eeerie ates SaSe ewe sea ebcsamae coeeoeciscaeeooeee see 242,129 00

Annual income from the bequest -.... accneee sadeendlesacccmenticececs 30,910 14

12 PROGRAMME OF ORGANIZATION.

13. For the present, or until the building is fully completed, be-
sides the Secretary, no permanent assistant will be required, except
one, to act as librarian.

14. The Secretary, by the law of Congress, is alone responsible to
the Regents. He shall take charge of the building and property,
keep a record of proceedings, discharge the duties of librarian and
keeper of the museum, and may, with the consent of the Regents,
employ assistants.

15. The Secretary and his assistants, during the session of Congress,
will be required to illustrate new discoveries in science, and to exhibit
new objects of art ; distinguished individuals should also be invited
to give lectures on subjects of general interest.

This programme, which was at first adopted provisionally, has
become the settled policy of the Institution. The only material
change is that expressed by the following resolutions, adopted Jan-
uary 15, 1855, viz:

Resolved, That the 7th resolution passed by the Board of Regents,
on the 26th of January, 1847, requiring an equal division of the in-
come between the active operations and the museum and library,
when the buildings are completed, be, and it is hereby, repealed.

ftesolved, That hereafter the annual appropriations shall be appor-
tioned specifically among the different objects and operations of the
Institution, in such manner as may, in the judgment of the Regents,
be necessary and proper for each, according to its intrinsic import-
ance, and a compliance in good faith with the law.

REPORT OF THE SECRETARY.

To the Board of Regents :

GENTLEMEN : I have the honor again, at the commencement of your
annual session, to present the report for another year of the opera-
tions of the Institution intrusted by the General Government of the
United States to your special care.

So much public attention has been absorbed during the last year
by the exciting events of the war that we might at first suppose
that little or no thought could be bestowed upon purely scientific
subjects, such as fall within the province of this Institution to culti-
vate, or indeed upon any kind of knowledge which has not an im-
mediate bearing on the special requirements of the times. But even
in the most sanguinary and gigantic warfare the responsibility for
the important plans which are to determine the result of the conflict
devolves upon the few, and leaves the many to fall into a condition
of comparative mental inactivity.

As arelief from the tedium of this condition, or a prevention from
falling into it, a large number of subordinate officers, and even pri-
vates, of the army have devoted themselves to pursuits connected
with natural history, or to the solution of problems of a theoretical
or practical character.

Although the immediate object of war is the destruction of life
and property, yet astate of modern warfare is not a condition of
evil unmingled with good. Independent of the political results
which may flow from it, scientific truths are frequently developed
during its existence of much theoretical as well as of practical im-
portance. The art of destroying life, as well as that of preserving it,
calls for the application of scientific principles, and the institution of
scientific experiments on a scale of magnitude which would never be
attempted in time of peace. New investigations as to the strength
of materials, the laws of projectiles, the resistance of fluids, the ap-
plications of electricity, light, heat, and chemical action, as well as of
aerostation, are all required.

The collection of immense armies of individuals of different ages

14 REPORT OF THE SECRETARY.

and nations affords the means of obtaining data of much interest to
the ethnologist, while the facts which are githered from the unusual
experience of the battle-field and hospital afford materials for the
advance of physiology, surgery, and medicine, which a century of
ordinary observation would fail to furnish.

In illustration of what has been done in the line we have mentioned,
I would refer to the extended labors of the Sanitary Commission and
of the department under the direction of the Surgeon General.
The one, besides aiding in the improvement of the health and com-
fort of the soldiers, has collected a large number of interesting facts
relative to the moral and economical condition of the army; while the
other, in addition to its immense labors in the care of the sick and the
wounded, has recorded the statistics of every part of its varied
operations, and formed a collection of illustrations of surgical anatomy
which is perhaps unrivalled in any part of the world.

In reference to all the inquiries to which I have alluded, the Smith-
sonian Institution has been called upon for aid and counsel, and has
continually rendered active co-operation and assistance. Its labors,
however, in this line, as well as in several other branches of its ordi-
nary operations, are not attended with results which can be given to
the world through its publications.

During the continuance of the war we must expect to find that
more attention is given to the collection of facts than to the deduction
from them of general principles ; the latter must be deferred to a
period of more tranquillity, when the mind is in a better condition
for continued application to the development of a single idea; con-
sequently the number of papers which have been presented to the
Institution since the date of the last report is less than that of any
previous year.

The meteorological system which had been established, and was in
successful operation for several years before the commencement of
the war, has been much deranged, few records of observations having
been received from the middle States and none from the southern;
still, as I have before intimated, the labors of the Institution have
been industriously pursued in lines more in accordance with the
peculiar condition of the country. <A large portion of all the time of
the Secretary has been devoted to inquiries referred to the Institu-
tion by the different departments of government. The work of pre-
paring the duplicate specimens of the Institution for distribution
has been continued. The library has been thoroughly overhauled,

REPORT OF THE SECRETARY. U5

partially rearranged, and a new catalogue of the transactions and
proceedings of learned societies prepared for publication. Ex-
tensive repairs and improvements have been made in the build-
ing, by which several rooms, previously occupied by tanks for receiy-
ing rain water, now rendered useless by the introduction of Potomac
water, have been reclaimed for other uses.

The efficient income of the Institution has been very essentially
impaired during the past year. Ist. By the increased price of
all the materials of printing and other articles used in the opera-
tions of the establishment. 2d. Qn account of the high premium
on gold required to pay the agents of the Institution in Europe and
to meet the incidental expenses of exchanges, and the cost of serials
and other works necessary for the use of the collaborators and other
persons engaged in researches for the Institution. 3d. In conse-
quence of the non-payment of the interest on the southern State
stocks forming part of the extra fund.

Still it will be seen by the report of the Executive Committee that
the expenditures of the Institution during the past year have been
kept within the receipts, and a large balance retained in the treasury
to meet the contingencies which may arise, particularly in the present
unstable condition of public affairs.

The interest on the Indiana stock for the first half of the year was
paid in specie, which was deposited with Messrs. Riggs & Co., with
the understanding that it could be withdrawn in the same currency
at any time it might be required. In the settlement of the accounts
for the year this specie was sold and the premium added to the re-
ceipts.

A power of attorney has been forwarded from the President of the
United States to Messrs. Fladgate, Clarke & Finch, of London, author-
izing them to collect the remainder of the Smithsonian fund, which
was left, by the Honorable Mr. Rush, as the principal of an annuity to
the mother of the nephew of Smithson. The power of attorney was
forwarded to the care of Honorable Charles F. Adams, American
minister to England, and the money, when collected, will be de-
posited with George Peabody & Co., bankers, London, subject to the
order of the Institution.

As a fact connected with the history of this establishment, I may
mention that the charter of a society in this city known asthe National
Institute expired in July last, and that in accordance with the law of

16 REPORT OF THE SECRETARY.

Congress incorporating that society, the Secretary of the Interior de-
livered the remainder of its library and museum to this Institution.

The National Institute was founded twenty years ago, for the culti-
vation of science, by a number of gentlemen of the city of Washing-
ton, most of them connected with the government. It at first found
favor with the public, and the hope was entertained that an
enduwment, in the form of a donation of land, or otherwise, would be
granted by Congress, by which it would be enabled to support a
museum and a library, and publish a series of transactions ; but this
hope was not realized, and as the field it proposed to occupy fell
within the province of the Smithsonian Institution, the society grad-
ually declined in activity, and finally allowed its charter to expire by
its own limitation. Before the organization of the Smithsonian Institu-
tion, the personal effects of Smithson, and the large collection of speci-
mens procured by the exploring expedition, were placed in charge of
the National Institute, and from the similarity of names the two estab-
lishments were at first frequently confounded with one another.

A large number of valuable books and specimens were presented
to the Institute by various societies and individuals; but as there was
not suflicient means to constantly employ a curator, or even to supply
appropriate rooms for their preservation, these collections have been
rendered comparatively of little importance. The specimens in
ornithology and entomology were almost entirely destroyed by in-
sects, and the library reduced principally to broken sets of periodicals
and transactions of learned societies, duplicates of those already
‘in the library of the Institution. In some cases, however, we have
been enabled to supply deficiencies, and the books so incorporated
into the Smithsonian collection have been properly designated by an
appropriate mark in the manuscript catalogue of the library. The
most valuable part of these collections was that which related to
mineralogy and ethnology.

Publications. The publications of the Institution, as stated in previ-
ous reports, consist of three series: Ist. The Contributions to Knowl-
edge. 2d. The Miscellaneous Collections. 3d. The Annual Reports.

The Contributions include memoirs embracing the records of origi-
nal investigations and researches, resulting in new truths, such as are
considered interesting additions to the sum of human knowledge.
Twelve volumes in quarto of this series have been published—the
thirteenth is still in the press.

REPORT OF THE SECRETARY. Ve

The Miscellaneous Collections include works intended to facilitate
the study of the various branches of natural history, to give instruc-
tion as to the method of observing natural phenomena, and to furnish
a variety of other matter connected with the progress of science. Of
this series four large octavo volumes have been issued, and a fifth
has been commenced.

The Annual Reports to Congress consist, each, of an octavo volume
of 450 pages. They contain the report of the Secretary as to the
operations and condition of the Institution, the acts of the Regents,
and an appendix, giving a synopsis of the lectures delivered at the
Institution, extracts from correspondence, and articles of a character
suited to meteorological observers, to teachers, and other persons
especially interested in the promotion of knowledge.

Contributions to knowledge.-—The following papers have been ac-
cepted for publication in the 15th volume of Contributions:

1. The concluding paper of Dr. Kane’s Series of Observations in
the Arctic Regions.

2. The reductions of the observations of McClintock while in search
of Sir John Franklin.

3. Parts II to VI of the Reduction of the Girard College Observa-
tions, by Professor Bache.

4, Ancient Mining on the Shores of Lake Superior, by Charles
Whittlesey.

5. On Respiration in the Chelonia, by Drs. Mitchell and Morehouse.

6. On Magnetic Observations in Pennsylvania and adjacent States,.
by Professor Bache.

In the reports for 1859 and 1860 accounts are given of two parts
(which were subsequently divided into three parts) of a series of
redactions of the magnetic observations made at Girard College,
Philadelphia, from 1840 to 1845, inclusive, by Professor Bache. The
first two of these papers relate to the investigation of what is called
the eleven-year period of the variations of the needle, which coin-
cides with the recurrence in frequency of the spots on the sun. The
third paper relates to the influence of the moon on the variation of
the magnetic needle as shown by the Girard observations.

Of the same series there have been accepted and printed parts 4,
5, and 6. The fourth refers to the change of horizontal force coin-
ciding with the eleven-year period of the spots on the sun. In ex-
planation of this it may be stated that the whole magnetic force of

the earth upon a needle freely suspended causes it to take a direction
H. Mis. Doe. 25 2

18 REPORT OF THE SECRETARY.

inclined to the horizon, at all places north and south of the magnetic
equator, which direction is called the magnetic dip or inclination.
The force with which the needle is drawn into this position may be
resolved into two forces—one in the plane of the horizon, and the
other perpendicular to this plane. By knowing the horizontal con- -
ponent, and the angle of the dip, the total force may be readily eal-
culated, and as this element can be much more accurately determined
than that in the line of the dip, it is the one which is generally made
the object of observation.

In the case of the observations made by Professor Bache, the in-
strument employed was one of Gauss’s large bifilar magnetometers,
which cousisted of a magnetic bar weighing twenty-five pounds,
upwards of thirty-six inches long, and suspended horizontally by two
long fine wires slightly diverging from parallelism. This magnetic
bar instead of being allowed to take a north and south position, or to
settle in the direction of the magnetic meridian, was forced to turn
nearly at right angles to this position by twisting the pair of suspen-
sion wires so as to overcome the directive force of the magnetism of
the earth. In this position the bar was in a state of equilibrium
between two forces, viz: the torsion of the wires tending to
turn the north end of the needle round towards the west, and the
horizontal magnetic force of the earth which tended to draw it back
intc the meridian. In this condition, if the magnetism of the earth
diminishes, the force of torsion will prevail, and the bar will move -
from the meridian. If the magnetism of the earth increases, the
torsion will be relatively weaker,and the bar will move in an opposite
direction. Attached to this bar was a mirror which, reflecting the
image of the divisions of a scale into the object glass of a telescope,
enabled the observer to perceive a variation in the intensity of the
force, equivalent to a ten-thousandth part of the whole force.

The indications of this instrument were corrected for variations in
magnetism produced by changes of temperature, and for a constant
small diminution in the intensity of the bar, from an actual loss of its
magnetic force. But besides these changes in the magnetism of the
bar itself, there is a progressive change in the horizontal component
of the earth’s magnetism, which may be due either toa change in the
direction of the force, or to a change of its intensity. After allowing
for these, from observations made in various parts of the earth on
changes of direction and intensity, the next step was to separate the
large disturbances, which have been called magnetic storms, from the

REPORT OF THE SECRETARY. 19

series of ordinary records. For this purpose deviations from the nor-
mal position of the bar amounting to thirty-three scale divisions were
considered as due to abnormal disturbances of this kind. This num-
ber was ascertained by a theorem founded on the doctrine of proba-
bilities, for which we are indebted to Professor Pierce, of Cambridge.
Out of 24,231 observations, 1,698, according to this criterion, were
considered asabnormal disturbances. After all the larger disturbances
were excluded, new monthly means were taken, and all deviations
from these of thirty-three divisions were again set apart. .

The result of this elaborate investigation is, that the variation in
intensity of the horizontal component of the earth’s force is subject
to a change coincident with that found from observations in other
parts of the world, which has been called the eleven-year period, or
tbat corresponding with the frequency of the appearance of the spots
on the sun. The observations extended only through five years,
which was less than half the whole period ; the data were not there-'
fore sufficient to determine the movement through its complete cycle,
although they served to mark the minimum point and the ascending
and descending parts of the curves of illustration between two
maxima. |

The fifth part relates to investigations on the effect of the sun in
producing daily and annual variations of the horizontal component
of the magnetic force. These investigations were made upon the
quantities which remained after removing from the tables the larger
or fitful disturbances previously described, leaving the normal effect
due to the sun from a change in its distance from the earth, and per-
haps from a change in the relative position of its magnetic poles on
account of the revolution of the earth in its orbit. Blanks in the
tables of observations were filled by interpolation. From these in-
vestigations it appears that the horizontal magnetic force of the earth,
or the intensity with which a deflected magnetic needle is drawn
back toward the north, varies with the different hours of the day.
The variation is greatest in summer and least in winter; the force is
most intense at a little after 6 o’clock in the morning, and diminishes
rapidly until a little after 10 o’clock a. m., when it reaches its mini-
mum, and again commences to increase, and continues to do so until
about 3 o’clock p. m., when it again declines until about 11 0’ clock
at night. The amount of change is much greater in the day time
than at night, the whole indicating that this daily variation depends
on the varying heat derived from the sun.

20 REPORT OF THE SECRETARY.

The 6th and last part of this interesting series relates to the lunar
influence on the horizontal magnetic force.

Each observation, after being corrected for temperature and for the
progressive changes in the earth’s magnetism, was marked with the
corresponding lunar hours, reckoning from the passage of the moon
over the meridian. The difference was then taken between the posi-
tion of the magnetic bar, as calculated from all the hours and
that found by observation at each lunar hour, and the difference
was considered as the effect of the magnetism of the moon on the
earth.

From these and similar observations, it appears that the moon
exerts a magnetic influence on the earth. The principal magnetic
effect takes place 2h. 52 m. after the upper passage of the mcon
over the meridian; secondary effect, 1 h. 7m. ; lower passage, princi-
pal minimum, at 6 h. 41”; lower passage, secondary minimum, at 8
h. 19m. after upper.

Another paper contains an abstract of the observations and results,
with the discussion of a detailed magnetic survey of Pennsylvania and
part of the adjacent States of New York, Ohio, and Maryland,
originally made by Professor Bache, and resurveyed By Mr. Charles
A. Schott.

In the study of terrestrial magnetism, two objects are essentially
necessary: first, the direction and intensity of the magnetic force of
the earth at a given epoch; and secondly, the variation in these ele-
ments after a known interval.

In 1840, 1841, and 1843, Professor Bache made a series of obser-
vations to determine the magnetic elements at a number of prominent
places in Pennsylvania, New York, Ohio, Mary yland, and Canada. The
whole number of stations at which he ascertained the declination or
yariation was 16, and of those where the dip and intensity was ob-
served 48.

Last summer Mr. C. A. Schott, an assistant in the coast survey,
visited six of the stations at which Professor Bache had previously
observed the magnetic elements, and by carefully redetermining
them obtained the data for calculating the secular changes which
had taken place during an interval of about twenty-years. The ob-
servations originally made by Professor Bache, and also the late ones
by Mr. Schott, were obtained with instruments of great precision,
end will always furnish the elements of future comparison for the
study of the changes which the magnetic force of the earth undergoes

REPORT OF THE SECRETARY. 21

in long periods. The paper commences with an abstract of those on
the declination. To these are added the latitudes and longitudes of
the places observed.

The observed magnetic variations, at the different places, have
been reduced to the epoch of January, 1842, by adding the annual
increase, namely 2’ 7, found by comparing the observations of 1840
with those of 1862. An elaborate discussion of the horizontal force
furnishes a comparison of European and American results. The de-
ductions from the observations on the dip of the needle are given
in terms of geographical latitude and longitude, and the isoclinal
lines or lines of equal dip are protracted on a map which also con-
tains the lines of equal magnetic force, both in regard to its
horizontal and total intensity. Three of the stations visited by Mr.
Schott fell within the scope of the coast survey; and the expense of
the redetermination of the magnetic elements, at these points, was
defrayed by the superintendent of that work; the determinations at
the remaining stations were at the expense of the Smithsonian Insti-
tution.

An account of the other papers in this volume has been given in
the previous report.

Miscellaneous Collections. —Several series of articles forming parts of
the series of Miscellaneous Collections, as stated in previous reports,
have been undertaken, of which some have been completed, some are
still in hand, and others have been printed during the past year.

The first of these series is that relating to the shells of North
America, and will consist of the following works :

1. Check lists of North American shells, by P. P. Carpenter, &c.

2. Circular relative to collecting shells.

3. Elementary introduction to the study of conchology, by P. P.
Carpenter.

4, List of the species of shells collected by the United States ex-
ploring expedition, by the same author.

5. Descriptive catalogue of the shells of the west coast of the
United States, Mexico, and Central America, by the same author.

6. Descriptive catalogue of the air-breathing shells of North
America, by W. G. Binney.

7. Descriptive catalogue of several genera of water-breathing
fresh-water univalves, by the same author.

8. Descriptive catalogue of the Jelaniadae, or the remainder of ihe
water-breathing fresh water univalves, by George W. Tryon.

22 : REPORT OF THE SECRETARY.

9. Descriptive catalogue of the Corbiculidae or Cyclodidae, a group
of bivalves principally inhabiting fresh-water, by Temple Prime.

10. Descriptive catalogue of the Unionidae, or fresh-water mussels.

11. Descriptive catalogue of the shells of the eastern coast of the
United States, by W. Stimpson.

12. Bibliography of North American conchology, by W. G. Binney.

The first and second articles of the foregoing list were printed in
1860, and described in the report for that year, and since then in
their wide distribution have done good service in facilitating the
collecting, labelling, and exchanging of specimens of conchology.

The third article was published in 1861, asa part of the annual report
for 1860, and a new ecition will be incorporated in the Miscellaneous
Collections as soon as we can procure the long-promised wood-cuts
from the British Museum, to illustrate the work.

The fourth and fifth articles are still in the hands of Mr. Carpen-
ter, and will, it is expected, be ready for the press the ensuing year.

With reference to the sixth article, it may be mentioned that for
many years before his death, the late Dr. Amos Binney, of Boston,
was engaged in collecting and arranging materials for a general work
upon the land shells of the United States. The result of his labors
was published after -his decease, in three large volumes, giving co-
pious descriptions and accurate figures of all the species. His col-
lections are now in the hands of his son, Mr. W. G. Binney, of Bur-
lington, New Jersey, who has since greatly extended them, and has
brought up the subject of his father’s work to the present day, by
various supplements, memoirs, &c. He has also lately rearranzed
all the materials in his possession, and prepared from them, for this
Institution, the synopsis which is given as the sixth article in the
above enumeration. ;

The seventh and -eighth articles include an account of fresh-water
univalves of the United States. Within the last twenty years the
yumber of described species of this class of animals known in this
country has greatly increased. The descriptions of these previously
made were from specimens collected in isolated situations, oftentimes
by persons who had not had the opportunity of studying large col-
lections or of comparing typical specimens, and, indeed, in some
cases without access to descriptions which had been previously made
by others. The shells belonging to this class are characterized, per-
haps above most others, by a remarkable range of variation in form
and size arising from local causes, or different stages of growth, &e.

REPORT OF THE SECRETARY. 23

Many of them are also furnished with so few positive specific external
characters, that for their determination an anatomical difference in
their soft parts can alone be depended upon. Tostudy, therefore,
satisfactorily single species of fluviatile shells, one must have before
him, says Mr. Binney, a very large suite of specimens of all ages, from
every portion of the district which it inhabits, as well as authentic speci-
mens of every allied described species, with an equally complete set
of individuals. Yrom these facts it is evident that among the descrip-
tions of these shells which have been made by different authors, and
published in different works, there must be many which refer to the
same species; or, in other words, that the bibliography of this branch
of natural history must abound in synonyms exceedingly perplexing
to the student, as well as exhibit imperfections in the systematic
exposition of the subject which ought not to exist. Such a con-
dition must occur from time to time in every branch of natural
history, and it therefore becomes important that some person com-
petent to the task should go over the whole field and reduce to what
is called a monograph, or single sketch, all that has been previously
done in regard to it.

Mr. Binney in his portion of the catalogue does not attempt to pre-
sent a complete monograph, but rather a report on our present state
of knowledge relative to fluviatile univalves. He has given an Eng-
lish translation of all the original descriptions and a fac-simile of the
outline of each original figure. The portion of this work which re-
lates to the fresh-water univalves of North America intrusted to Mr.
Binney has been completed, and is now in the press. The remainder
on the Melaniadae, undertaken by Mr. Tryon, has been commenced;
but since the family contains a large number of species exhibiting
many of the variations above-mentioned, a year or more will be re-
quired before it can be completed.

The ninth article, or that relating to the Cycladidae, is nearly ready
for the press. The recent species of this group are generally small
and inhabit the fresh waters of various parts of the world, although
some belong to brackish or even marine localities. Mr. Prime has
paid particular attention to this group, and is said to be one of the
first living authorities in regard to the subject.

The eleventh article of the above-mentioned series will include
detailed descriptions by Mr. Stimpson of all the marine shells of the
eastern coastof the United States, with original notices of the internal
structure,

24 REPORT OF THE SECRETARY.

The twelfth article in the series above enumerated is the biblio-
graphy of conchology, which has been prepared to avoid the neces-
sity of repeating bibliographical references in the different manuals
just enumerated. It is intended to give, first, an account of all the
articles or works of American authors, relative to conchology in
general, and secondly, those of foreign writers relative to the con-
chology of North America.

All the species referred to by authors are enumerated after the
title of each article, and such references to the page and date of
description are given as will enable any species to be quoted from
the bibliography itself without the necessity of referring to the origi-
nal. A complete index of authors, and of all the species mentioned,
placed at the end of the work, will greatly facilitate its use. The
first part of this work, embracing the writings of American authors,
forms an entire volume of the Miscellaneous Collections of upward of
700 pages, of which 400 are already stereotyped.

Another series of works belonging tothe Miscellaneous Collections
is intended to facilitate the study and the advancement of the science
of entomology, of which the several articles are the following:

1. Instructions for collecting and preserving insects.

2. Catglogue of the described Diptera (flies, mosquitoes, &c.) of
North America, by Baron Osten Sacken.

3. Catalogue of the described Lepidoptera (butterflies, moths,
&c.) of North America, by Dr. Jno. G. Morris.

4. Classification of the Coleoptera (beetles, &c.) of North America,
by Dr. Jno. L. LeConte.

5. Synopsis of the described Neuroptera (dragon flies, &c.) of
North America, with a list of the South American species, by
Hermann Hagen.

6. Synopsis of the described Lepidoptera of North America. Pt.
1, Diurnal & Crepuscular Lepidoptera, by Dr. Jno. G. Morris.

7. List of the Coleoptera of North America, with descriptions of
new species, by Dr. John L. LeConte.

8. Monographs of the Diptera of North America, by H. Loew, with
staliote by Osten Sacken.

9. Catalogues of Homoptera and Hemiptera (chinches, roaches,
&c.) of North America, by P. R. Uhler.

10. Descriptive catalogue of the Hymenoptera (bees, wasps, &c.)
of North America, by Dr. Henri DeSaussure.

These have all been described in previous reports, and have all been

REPORT OF THE SECRETARY. 25

printed excepting the 9th and 10th, which are still in preparation,
and a part of the Tth, which has been delayed on account of the call
on Dr. LeConte to a position in the medical department of the army
of the United States.

‘The instructions for collecting and preserving insects were published
in the appendix to the report for 1858. A new and enlarged edition
will be published during the coming year as a part of the next volume
of the Miscelloneous Collections.

Another part of the Miscellaneous Collections is a series of tables
furnished by Professor Guyot in addition to the set of physical tables
by the same author, previously published by the Institution. The
first of these is intended for converting the klafter and feet of Vienna
into measures of length of other countries. They are to be substituted
for those contained in the former edition, because they are derived
from a new comparison of the klafter of Vienna and French toise, by
Von Struve and Von Littrow. This comparison has furnished the
standard adopted in the great trigonometrical survey of Austria.
The second set of tables is for converting the Spanish or Mexican
and Bolivian varas and feet into English and French measures.

The preceding tables have been printed, and are inserted in volume
I of the Miscellaneous Collections.

The third set of tables gives the value of a degree of the meridian
in every degree of latitude from the equator to the poles, in metres,
kilometres, German miles, nautical leagues, French leagues, geo-
graphical or nautical miles, and English statute miles.

The fourth set of tables gives the value of each degree of longitude
on each parallel of latitude, from 0° to 90°, in the same measures as
those mentioned above.

The two preceding sets of tables, which are based on Bessel’s ter-
restrial elements, have been computed under the direction of Professor
Bache at the office of the Coast Survey, and have been kindly fur-
nished by him for this volume. The columns of the German miles and
nautical and French leagues have been added to make the table more
complete.

The fifth set of tables is for converting the most usual measures of
lengih into each other, such as myriametres and kilometres, Austrian,
Prussian, and German miles, nautical leagues, French, Spanish, and
Mexican leagues, geographical or nautical and statute miles, and Russian
wersts.

26 REPORT OF THE SECRETARY.

The sixth set of tables is for the conversion of the corresponding
surface or square measures of the preceding table into each other.

These measures, which are also founded on the late terrestrial ele-
ments of Bessel, have been selected with reference to the frequency
of use in the consultations of the official publications of different
Ruropean nations. Each of the above tables furnishes the value of
every full number from 1 to 100, in six figures for the measures of
length, and seven for those of surface.

The seventh set of tables gives the velocity of rotation of the earth
for each degree of latitude, expressed in the measures of length most
frequently used, and will facilitate computations in regard to the
velocity of the wind.

Lhe whole series comprises over 17,000 separate numbers, filling
70 large octavo pages.

It is proposed to add to these tables one giving the length of time
of sunshine in different latitudes for each day in the year, and, to
complete the series, a number of tables for calculating the resultant
direction of the winds.

It is believed that these tables will be received as a welcome addi-
tion to the physical tables previously published by the Institution,
and which are now well known and used in every part of the civilized
world. They will be of value to the meteorologist and physical
geographer, as well as to the statistician and political economist.
The first set is indispensable for easily computing distances on globes,
maps, &c.; the second will greatly facilitate the use of the numerous
data furnished by travellers, scientific publications, and especially
the official statistical information contained in the various documents
of the states of Europe. The selection of the various measures is
made with special reference to the latter

as the myriametre and ©
kilometre for the study of later French publications, and the com-
mon French league for the older ones; the Austrian and Prussian
miles, the Russian werst, and English statute mile for publications in
the countries where those measures are used. In the preparation of
these tables a question has arisen whether an additional series
should be constructed for the conversion of the American foot into

the English, between which there is, unfortunately, a slight dif-
ference. ;

feporis.—The annual reports to Congress are printed at the ex-
pense of the government, with the exception of the cost of the

REPORT OF THE SECRETARY. Dad

wood-cuts, which is at the expense of the Institution. The re-
port for 1861 contains, besides the report of the Secretary and the acts
of the Regents, a Eulogy on Prof. Felton, by Dr. Woolsey, President
of Yale College; a Eulogy on Hon. Stephen A..Douglas, by Hon. 8. 8.
Cox ; synopsis of lectures on the Construction of Bridges, by Fair-
man Rogers, of the University of Pennsylvania; lecture on the rela-
tion of Time and Space, by Prof. 8. Alexander, of the College of New
Jersey; lecture on Arctic Explorations, by Dr. I. I. Hayes ; a memoir
of Geoffroy St. Hilaire, by M. Flourens ; the chemical analysis of the
‘Sun by means of the Solar Spectrum ; the smail planets between Mars
and Jupiter; studies and experiments on Metamorphism, by M.
Daubrée, and anumber of articles on Archeology, all translated for the
Institution ; also a report on Nitrification, prepared for the Institution
by B. F. Craig, M.D.; the history of Petroleum, by T. Sterry Hunt ;
and the explosibility of Coal Oil, by Z. Allen ; list of birds inhabiting
the District of Columbia, by E. Coues and D. W. Prentiss;.and a
series of prize questions of scientific societies, together with a num-
ber of minor articles.

The reports for a number of years past have contained a series of
memoirs of distinguished men of science, members of the French
Academy, translated for the Institution by C. A. Alexander, Esq., of
this city. It is intended to continue the translation and publication
of similar memoirs, and when the number is sufficient to form an
ordinary sized volume, to collect and publish them in a separate
form.

Of the last report, 10,000 extra copies were ordered by Congress, of
which 4,000 were presented to the Institution for distribution among
its special: correspondents. The requests for copies of this work
have been constantly increasing from year to year, and it is to be
regretted that the pages were not stereotyed, since there is now a
large demand for back numbers, to complete sets, which cannot be
obtained.

Previous to last year we were allowed to have extra copies of cer-
tain articles of the report struck off for separate distribution, but
under the new rules for the regulation of the public printing this
privilege was denied us in the case of the report for 1861. It is
thought, however, that if a proper statement were made to Congress,
a clause would be added to the acts relative to the government
printing which would give all the facilities required.

28 REPORT OF THE SECRETARY.

The following general rules for the distribution of the reports have
been adopted :

Ist. They are presented to all the meteorological observers who
send records of the weather to the Institution.

2d. To the collaborators of the Institution.

od. To donors to the museum or library.

4th. To colleges and educational establishments.

oth. To public libraries and literary and scientific societies.

6th. To teachers, or individuals who are engaged in special studies,
and who make direct application for them.

It is proper to remark that, owing to the many changes which have
taken place since the commencement of the war in the list of corre-
spondents of the Institution, it has not been thought advisable to send
the report, as heretofore, to all whose names are on the record of
distribution, but in most cases to wait until direct application is made
by letter for a copy of the work. Whenever a report is sent to any
address, a separate announcement is made through the mail by enclos-
ing a blank receipt, to be signed and returned to the Institution.

In view of the great cost of paper at the present time and the
space required for storage of a large edition of each volume of the
publications of the Institution, it has been thought advisable to ste-
reotype the text and strike off only as many copies as are required for
immediate distribution, printing a new supply from time to time to
satisfy the demands as they arise. By the adoption of this plan,
should the cost of paper return to its normal rate, the expense of the
stereotype plates would be saved.

Meteorology.—The meteorological system has continued to be car-
ried on as in former years, though necessarily very much dimin-
ished in extent on account of the absence of records from the southern
States. The volume of meteorological reductions from 1854 to 1859,
an account of which was given in the last report, has been published
and distributed to the meteorological observers, to public lbraries,
and foreign institutions. Many letters have been received expressing
the new interest in the system that has been awakened by the appear-
ance of this volume, and the records which before existed only in the
archives of the Institution are now in the hands of a large number
of the students of science, whose various tastes and abilities, will
enable them to draw from them important general results. The
second volume is still in press at the Government office, the print-

REPORT OF THE SECRETARY. 29

ing of it having been delayed by that of documents of more im-
mediate importance. It is expected, however, that it will be finished
during the year 1863.

The daily telegraphic bulletin of the state of the weather, which
was entirely discontinued for some time on account of the demands of
public business, has been partially resumed, and we are indebted to
the courtesy of Mr. Anson Stager for occasional despatches since
the early part of December last, from stations in the Rocky moun-
tains, and even from points as far west as California. These telegrams,
however are not sufficient to enable us to predict, with much proba-
bility, the changes of weather, without the additional information from
the south and southwest. The telegraphic bulletin giving the daily
condition of the weather at various important positions on the con-
tinent of Europe continues to be lithographed by the Imperial Ob-
servatory at Paris, and is sent to the Institution by every steamer.

In May last a circular was distributed asking for information on
the subject of tornadoes, the principal design of which is to direct
attention to a full and definite system of observations, so that on the
recurrence of tornadoes precise and uniform reports may be obtained
as to all the features of the phenomenon. In addition to the special
replies to the circular, a number of general answers have been re-
ceived, which are of interest in helping to define the regions of our
country where these destructive visitants frequently appear, and
those in which they are happily almost unknown. From Steuben,
Maine, Mr. J. D. Parker writes: ‘‘There was never a tornado seen
hereabouts by any one, so far as I can learn;’’ and Mr. R. H. Gar-
diner, at Gardiner, in the same State, says: ‘‘ Tornadoes are of very
rare occurence in this part of the country. I have no knowledge of
any within the last fifty years.’’ From Vermont, Mr. Hiram A.
Cutting, of Lunenburg, informs us that ‘‘there never was but one
tornado, in this section, in my remembrance, and that was at Victory,
about twenty miles northwest of this place, in the summer of 1842.”
Mr. Levi Packard, residing in the State of New York, at Spencertown,
Columbia county, between the Hudson river and Massachusetts, tells
us there are no tornadoes in that tract of country. On the other hand,
we are informed that over the swampy region of the great bend of the
Mississippi tornadoes are very frequent, and the paths of many of them
are marked upon the ground for miles by prostrate trees and other
indications of a violent disturbance of the atmosphere.

oo

0 REPORT OF THE SECRETARY.

Correct general information of this kind would furnish material for
the preparation of an interesting map, showing at a glance the
regions where tornadoes annually prevail, and those where they oc-
cur only occasionally, or not at all. In meteorological investiga-
tion we always make a step in advance when the region to which
phenomena are limited can be accurately defined.

Since the latter part of October, a series of daily observations has
been made for the Institution, by Mr. Force, on the temperature of
the hydrant water in Washington. The water flows some six or
seven miles through iron pipes, under ground, before reaching the
place of delivery,,and acquires, approximately, the temperature of
the soil at the depth at which the pipes are laid. The observations
were made at a hydrant out of doors, about 7 0’ clock every morning,
the water being allowed to flow two or three minutes before noting
the temperature. When the curves for the water and the air are
plotted on the same diagram and the same scale, they exhibit to the
eye, in avery striking manner, the extreme fluctuations of the tem-
perature of the air, compared with that of the ground, at the depth
of only two or three feet. They also show the slowness with which
variations of temperature penetrate the earth. The change pro-
duced by a decided increase or decrease of temperature being gene-
rally indicated by the water two or three days after it occurred in
the open air.

Among the contributions relative to meteorology which have been
received at the Institution, is a series of tri-daily observations made
at Brunswick, Maine, by the late Professor Parker Cleaveland, from
1808 to 1859. The records include observations on the ordi-
nary thermometer, the maximum and minimum thermometer, the
barometer, rain-gauge, wind-vane, &c. Itis proposed to publish these
in full, as a part of the second volume of the ‘‘Meteorological Re-
sults,” but for this purpose it is desirable that the means for months,
years, and the whole period, should be calculated, and this work is
now in progress, and will probably be finished before the printer
will call for the copy. The publication of these observations is in
accordance with the plan adopted to print in full a number of long
series of observations such as those we have already published, viz:
for Providence, Rhode Island, and Washington, Arkansas. They
will be of much interest for solving various meteorological problems,

such as the recurrence of particular phenomena, changes of seasons,

REPORT OF THE SECRETARY. SM

verification or disproval of the many empirical rules which have been
proposed and are used for predicting the weather, &c. . The exten-
sive series of observations made by Dr. 8. P. Hildreth, of Marietta,
Ohio, mentioned in a previous report, belong to the same class, and
will also be inserted in the volume above mentioned.

We have already referred to the additions to the meteorological
tables of Professor Guyot, and stated that it is proposed to still fur-
ther increase these tables by a series intended to facilitate the calcu-
lation of the mean direction of the wind.

The directions and blanks for making meteorological observations
which have been prepared and published at the expense of the In-
stitution have been extensively distributed in this country, and trans-
lated and reprinted abroad. The geographical and statistical society
of Mexico has recently adopted them, and signified the intention of
co-operating with the Institution in extending its system of observa-
tions more widely over this continent. Were not our general system
of meteorology interrupted by the discontinuance of the reception of
observations from the southern States, this would be an important
addition to our means of tracing the extent of disturbance of the
atmosphere which accompanies our winter storms.

Professor Guyot availed himself of a visit which he made to Europe
last year to establish by his own observation the relation of the
standard barometers used by the Institution to the most important
standards of the European observatories. The comparisons were
made by means of two Fortin barometers, with cistern of constant
level, as modified by Ernst, of Paris, and constructed several years
avo by that skilful artist for the Institution. Both instruments had
been previously tested by long usage, and just before leaving this
country their relation to a large standard barometer by Newman, of
London, and a large sized barometer by Ernst, was ascertained by a
series of numerous comparisons made with great care. “These two
instruments were directly compared in Europe with a standard
barometer at Kew observatory, now acknowledged as the nor-
mal barometer among English meteorologists, and with the stan-
dard instruments at the Brussels, Berlin, and Geneva observatories,
by the kind permission and assistance of the directors of these several
institutions, Professors Stanley, Quetelet, Enke, and Plantamour.
The last set of comparisons at Geneva, Switzerland, was found par-
ticularly useful from the fact that by the untiring care of Professor
Plantamour the relation of his barometer has been fully established

32 REPORT OF THE SECRETARY.

with that of Regnault in the College de France, and that of the ob-
servatory of Paris. On his return Professor Guyot made a new series
of comparisons with the same Smithsonian standards as before,
the results of which proved that no change had taken place during
his absence in the two barometers used abroad. It is believed
that these comparisons establish a correspondence of the Euro-
pean and American standard barometers within the narrow limit
of one or two-thousandths of an inch. A large standard is about to
be prepared under the direction of Professor Guyot, to which these
determinations will be referred.

' The meteorological branch of the operations of the Institution still
continues under the charge of Mr. William Q. Force, to whose habits
of order and scrupulous accuracy the system is much indebted for
whatever value it possesses.

Among the contributions to the meteorological materials of the
Institution, presented during the last year, is a series of continuous
records of the changes of atmospheric temperature made by a ma-
chine invented by Dr. James Lewis, of Mohawk, New York. | This
instrument consists of an arrangement of a number of brass and iron
wires, whose relative contraction and expansion give motion to
a metallic point, the several positions of which are marked by a
puncture in a fillet of paper, produced by a blow of a hammer
moved by clockwork, repeated at regular intervals of fifteen minutes.
Although instruments of this kind have been frequently constructed,
they have generally not possessed sufficient sensibility to indicate the
fitful changes of the atmosphere. Dr. Lewis appears, however, to
have been more successful in his invention, and from the results
which he has presented to us it would appear that the registers of his
self-recording instrument are of considerable value in determining
the general law of changes of temperature, especially during the day,
and thus furnishing corrections by which the mean temperature of
places in the same latitude can be obtained from observations made
at only one or more hours of the day. It may be mentioned here
that an idea has been very prevalent in this country among observers
that to obtain the average temperature of a place, the best times of
observation are about sunrise and sunset, and at 2 or 3 o’clock in the
afternoon; but as the rising and setting of the sun occurs at different
times in different seasons of the year, and as the maximum tempera-
ture occurs at different hours in different latitudes, it is best always
to make the observations as nearly as possible at fixed hours, as, for

REPORT OF THE SECRETARY. So

instance, at those which have been adopted by this Institution, viz: T,
2,and 9; since, by observing this rule, corrections derived from such
observations as those made by Mr. Lewis can be applied soas to give with
more precision the average temperature of the place of observation.

The present Surgeon General, Dr. Hammond, takes a lively interest
in meteorology, as one of the branches of science intimately con-
nected with his department; and as soon as the posts and canton-
ments are again permanently established will reorganize the system
of army observations on a more extended scale, and furnish it. with
the instruments and instructions prepared under the direction of this
Institution.

Laboratory.—The operations of the laboratory during the past
year have principally consisted in the preparation of alarge quantity of
Laborraque’s disinfecting liquid, and the continuance of the examina-
tion of minerals preparatory to a distribution of duplicates. More than
a thousand bottles of the disinfecting liquid have been prepared for
the use of the hospitals in the city of Washington. The efficacy of
this substance has been demonstrated by abundant experience.
Simply sprinkling it on the floor, or wetting with it a cloth placed
near the source of unpleasant effluvia, at once renders the air of
the apartment entirely inodorous. The preparation of this substance
is still going on and will be continued as long as the article may be
required for the hospitals.

The examination of the minerals preparatory to a distribution of
the duplicates has not been carried on as rapidly as could be wished,
on account of the absence of the person to whom this duty was as-
signed. We have, however, ready for distribution, upwards of two
hundred sets of specimens, properly labelled, of the stones used in
erecting the public buildings in the city of Washington.

In consideration of the high rate of exchange no purchases of
foreign apparatus have been made during the past vear. Occasion
however, has been taken, in the interval of other business, to remodel
the cases of the apparatus room, in order to a better disposition and
display of the instruments. The room itself is fifty feet square with
a ceiling of twenty-five feet in height. Around the four sides of this
room, cases of about six feet deep and ten feet high have been con-
structed. The upper floorings of these cases extend about two feet
beyond their front, and thus form a projecting gallery entirely around
the room, which serves for the display of larger instruments as well

H. Mis. Doc. 25——3

34 REPORT OF THE SECRETARY.

as to increase the available capacity of the apartment. The whole
arrangement produces a pleasing architectural effect, while from the
size of the vases instruments may frequently be used in the way of
experiment without bringing them out into the room, or exposing
them to the handling of visitors.

Collections of Specimens of Natural History, &c.—In the last two re-
ports a distinction was drawn between the large collections of speci-
mens of natural history, &c., which have been made through the
agency of this Institution and what is called the Smithsonian Museum.
This distinction has become necessary in order to separate more
clearly in the public mind two objects, which, although they are gen-
erally confounded, are in the case of this Institution essentially dif-
ferent. The object of making large collections of duplicate speci-
mens is twofold, first, to advance science by furnishing to original
investigators, wherever they may reside, new materials for criti-
cal study; and second, to diffuse knowledge by providing colleges,
academies, and other educational establishments with the labelled
specimens necessary to give definite ideas of the relations and diver-
sities of the various productions of nature. The principal end
attained by the public museum of the Institution has been the grati-
fication and incidental instruction of the visitors to the city of Wash-
ington. It is true that there are preserved in the museum the type
specimens of the species and genera which have been described, and
of which accounts have been published at the expense of the Smith-
son fund, or by other means; but for the preservation of these there
is required no costly building nor corps of attendants, and, indeed,
the charge of them might well be assumed by other establishments.

From the foregoing exposition it will readily be seen that while
the collecting and distributing of large numbers of specimens is an
important means of increasing and diffusing knowledge, and as such
is in strict accordance with the will of the founder of this Institution,
the support of a public museum, the effects of which must of neces-
sity be in a great degree local, is not so consistent with the liberal
intention of the bequest.

It should not be inferred from the foregoing remarks that I mean to
disparage the establishment of a general collection of objects of na-
ture and art, like that of the British Museum or the Garden of Plants,
which includes in its design the encouragement of original study as
well as of popular instruction and amusement. On the contrary, I

REPORT OF THE SECRETARY. aD

have always advocated .this measure as one of national importance,
while I have endeavored to show that it ought not to be attempted
by means of the Smithsonian fund, and that it could only be properly
carried out bya liberal annual appropriation from the public treasury.

I have thought it necessary frequently to urge the importance of
guarding against the tendency to increase the expenditure on local
objects, and against accepting presents on condition that they shall
be perpetually preserved and exhibited to the public at the expense
of the Smithsonian fund. If this propensity were indulged in and
donations solicited on the terms mentioned, which are those usually
agreed to in similar cases, the whole income of the bequest would be
ultimately absorbed in providing house-room and accommodations for
the collections ; and the active operations, as they are called, which
have given so much celebrity to the name of Smithson, and have
constituted the distinctive feature of the establishment, would cease.

The collections of specimens which have formed the prominent sub-
ject of the preceding remarks may be divided into two classes,
namely, those which have been studied and an account of them pub-
lished in the reports of the government expeditions, or in the trans-
actions of the Smithsonian and other institutions, and those which
have not been described, and which consequently are considered of
much interest to the naturalist, who may be anxious to make new
explorations in the domain of natural history. Of both classes the
Institution possesses a large number, for the disposition of which the
following geueral rules have been adopted :

First. To advance original science, the duplicate type specimens
are distributed as widely as possible to scientific institutions in this
and other countries, to be used in identifying the species and genera
which have been described.

Second. For the purposes of education, duplicate sets of specimens,
properly labelled, are presented to colleges and other institutions of —
learning in this country.

Third. These donations are made on condition that due credit is to
be given the Institution in the labelling of the specimens, and in all
accounts which may be published of them.

Fourth. Specimens are presented to foreign institutions, on condi-
tion that if type specimens are wanted for comparison or other use
in this country they will be furnished when required.

Fifth. In return for specimens which may be presented to colleges
and other institutions, collections from localities in their vicinity shall -
be furnished when wanted.

36 REPORT OF THE SECRETARY.

In the disposition of the undescribed specimens of the collection,
the following considerations have been observed as governing prin-
ciples : | ‘

First. The original specimens are not to be intrusted for descrip-
tion to inexperienced persons, but to those only who have given evi-
dence of an ability properly to accomplish the task undertaken.

Second. Preference is to be given to those who have been engaged
in the laborious and difficult enterprise of making complete mono-
eraphs.

Third. The investigator may be allowed, in certain cases, to take
the specimens to his place of residence, and to retain them for study
a reasonable time.

Fourth. The use of the specimens is only to be given on condition
that a series of types for the Smithsonian Museum will be selected
and properly labelled, and the whole returned in good condition.

Fifth. In any publications which may be made of the results from
an investigation of the materials from the Smithsonian collection, full
credit must be accorded to the Institution for the facilities which
have been afforded.

During the past year, the labelling of specimens for colleges and
other educational institutions has been continued, but the work has
not advanced with as much rapidity as was expected, owing to the
eall upon many of our co-laborers to join the army. Under the
most favorable circumstances the labelling requires much labor, and
cannot be properly done except by persons specially trained in par-
ticular branches of natural history.

The assorting and labelling of the principal part of the shells is
still in progress under Mr. Philip P. Carpenter, of Warrington, Eng-
land, assisted by Dr. Alcock. Other shells have been named, or are
in the process of being named, by Prof. Agassiz and Dr. Stimpson,
of Cambridge; Mr. Isaac Lea and Mr. G. W. Tryon, of Philadel-
phia; Mr. W. G. Binney, of New Jersey ; Mr. Prime, of New York;
Mr. Busk, of England; and Dr. Steenstrup, of Copenhagen.

The botanical collections, to which several additions have been
made during the past year, are still in charge of Dr. Torrey, of New
York, and Dr. Gray, of Cambridge. The assorting of the rocks
and minerals is carried on in the Institution; and as an auxiliary
work, Mr. Egleston has prepared a general list of mineral species
to facilitate the labelling and exchange of specimens. This will be
printed and distributed to correspondents during the present year.

REPORT OF THE SECRETARY. 37

The additions to the collections of insects, during the year, have
been referred for identification, as usual, to the collaborators in the
line,of entomology, viz: To Baron Osten Sacken, Dr. Le Conte, Dr.
Loew, Dr. Hagen, Dr. Morris, Dr. Clemens, Mr. Edwards, Mr. Nor-
ton, Mr. Scudder, Mr. Ulke, and Mr. Ubler.

The whole number of entries on the record book of the Smith-
sonian collection, up to the end of 1862, is, according to the statement
of Professor Baird, 74,775, and when it is understood that each entry
is that of a lot which in most cases contains many specimens, some
idea may be formed of the whole number of specimens which have
been collected through the agency of the Institution, and the service
which will be rendered when all these are made available for the
advancement and diffusion of knowledge among men.

The Museum of the Institution consists principally of the type
specimens of the various collections of objects of natural history and
ethnology obtained by the different exploring and surveying expedi-
tions sent out by the government of the United States, as well as by
various special expeditions instituted at the expense of the Smithsonian
fund. These specimens have generally been described, and in many
cases figured in the reports published by Congress, or in the Smith -
sonian or other transactions, and have thus rendered their chief ser-
vice in the way of advancing knowledge. Yet, in view of the future
progress of science, it is important, irrespective of their use for the:
purposes of education, that these specimens should be carefully pre-
served, in order that they may be referred to as the original objects
from which the descriptions were drawn. It often happens that in
the subsequent study of similar specimens from other localities doubts
arise as to some points of the published descriptions, which can only
Le solved by a reference to the original materials, and it is also fre-
quently desirable to re-examine the specimens in relation to some
new point of interest which may have been developed in the course
of more extended investigation.

The additions to the museum should be confined principally to the
type specimens collected and described at the expense of the gen-
eral government, or under the immediate auspices of the Institution.
Iiven thus restricted the specimens will increase in number as rapidly
as that part of the Smithsonian fund, which is taxed for their sup-
port, will permit, and in time they will form of themselves a valu-
able collection of authentic illustrations of the natural history of
America. It is true, as is often urged, that the value of these speci-

38 REPORT OF THE SECRETARY.

mens would be enhanced by the addition for comparison of corre-
sponding specimens from other parts of the world; but the full
adoption of this extension of the plan would involve the maintenance
of a general museum, which, as has been repeatedly stated, is incom-
patible with the means and design of the Institution.

The only museum at present in this country, expressly established
for the threefold object of popular instruction, systematic study, and
original research, is that at Cambridge, under the direction of Prof.
Agassiz. For the purposes of such a museum specimens of all kinds,
from every part of the earth, are necessary, and in accordance with
the liberal policy by which it has always been governed, the Smith-
sonian Institution has actively co-operated in assisting this exemplary
enterprise of the State of Massachusetts.

During the past year the type specimens of a number of series of
collections, of which the duplicates have been separated for distribu-
tion, have been transferred to the museum. The work of labelling the
specimens, so that the common as well as the scientific name of each
article may be distinctly exhibited, has been continued, and will pro-
bably be completed before the end of the present year. But for an
account in detail of what has been done in regard to the museum
and the collections, I must refer to the report of Prof. Baird, here-_
with submitted. |

As a matter of interest, and, in some cases, of importance, a
record book is kept at the principal entrance of the building, in
which the names of all the visitors are entered. Since the date of
the last report the Institution has been visited by thousands of
persons, who have been called by business or pleasure to the national
capital. The specimens of natural history and ethnology have ex-
cited much popular interest, particularly among those who come
from the more distant western portions of the country. The museum
and grounds are a favorite resort for the convalescent soldiers.
The trees and shrubbery of the latter are growing finely, and the
whole park, under the care of the Commissioner of Public Build-

a
Ings,

B. B. French, Esq., forms no unworthy memento of the tal-
ents of the lamented Downing, by whom its plan was designed.

I amsorry, in this connection, to consider it my duty to refer to the
existence of an evil over which, though you have no official control,
yet as legislators and prominent citizens you may exert a beneficial
influence. I allude to the city canal, which forms the boundary of
the Smithsonian grounds on the north. The basin or widest part of

REPORT OF THE SECRETARY. 39

this canal, across which most of the visitors to the Institution have
to pass, has become, since the introduction of the Potomac water,
the receptacle of the sewage of the city, and is now an immense
cesspool, constantly emitting noxious efiluvia prejudicial to the health
and offensive to the senses of all who approach the locality. This
nuisance, which will continue to increase with the increasing use of the
Potomac water, may perhaps be mitigated by placing a gate at each
end of the wider part of the canal, to be closed after high tide and
opened occasionally at low water, so as to discharge the contents
with a force which would remove, in part, at least, the deleterious
deposit. But the only effectual remedy, as it appears to me, is to
fill up a part of the width of the canal, and convert the remainder
into a sewer by covering it with an arch of masonry. This sewer
may perhaps be cleared out by flood-gates, as before mentioned, or
by anchoring flat-boats at the mouths of the drains, to be removed
and emptied when filled. But whatever plan may be adopted, the
character and prosperity of the city, as well as the interests of the
Institution, are involved in a speedy and efiicient effort to remove
the evil. The small pecuniary benefit which may result from the
canal to the city or to individuals ought not have any weight in the
decision of this matter.

Explorations. —A part of the large collections which have just been
described was gathered through officers and other persons attached
to the surveying and exploring expeditions sent out by the govern-
ment, and another part by expeditions expressly organized for the
purpose, under the immediate auspices of the Institution. Among the
latter is the expedition mentioned in the last two reports as having
been undertaken by Mr. Robert Kennicott, of Chicago.

This enterprise has terminated very favorably, the explorer having
returned richly laden with specimens, after making a series of obser-
vations on the physical geography, ethnology, and the habits of ani-
mals of the regions visited, which cannot fail to furnish materials of
much interest to science.

The route traversed by Mr. Kennicott was from Lake Superior,
along Kamenistiquoy river, and Rainy and Winnipeg lakes, up the
Saskatchewan river to Cumberland House; thence nearly north
through a series of rivers and lakes to Fort Churchill on English
river, up the latter to Methy Portage, at which point he first reached
the headwaters of the streams flowing into the Arctic ocean; thence

40 REPORT OF THE SECRETARY.

along the Clear Water river and Athabasca lake, down Peace river
into Great Slave lake, and along the Mackenzie river to Fort Simpson.
At this place Mr. Kennicott spent a part of the first winter with the
officers of the Hudson’s Bay Company, making excursions up the Liard
river to Fort Liard in autumn, and again on snow shoes in January.
Before the close of the same winter he went up the Mackenzie to Big
island, and thence northwest to Fort Rae, near the site of old Fort
Providence. From this point he travelled on the ice across Great
Slave lake to Fort Resolution, at the mouth of Peace river, where he
spent the summer of 1860. THenext descended the Mackenzie to Peel’s
_ river, and thence proceeded westward across the Rocky mountains, and
down the Porcupine river to the Youkon, in the vicinity of which he
spent the winter of 186061, and the summer of 1861. The winter
of 1861 and’62 was spent at Peel’s river, and La Pierre’s house in the
Rocky mountains, and in travelling from this point up to Fort Simpson
and back to Fort Good Hope on the Mackenzie. He left the last-men-
tioned place on the Ist of June, 1862, and reached home in October.

During the whole exploration he.was the guest of the Hudson’s
Bay Company, the officers of which not only furnished him with free
transportation for the materials he collected, but also extended to him
in the most liberal manner the hospitalities of their several posis, and
facilitated in every way in their power the objects of his perilous
enterprise.

The principal object of the exploration was to collect materials for
investigating the Zoology of the region visited. Mr. Kennicoit,
however, also collected specimens of plants and minerals, and
gave considerable attention*to the ethnology of the country, in ob-
serving the peculiarities of the various Indian tribes, and forming
vocabularies of the languages. He carried with him a number of
thermometers, and succeeded in enlisting a number of persons as
meteorological observers, as well as in exciting an interest in natural
history, and in physical phenomena, which cannot fail to be produc-
tive of important information respecting a region of the globe but
little known.

The contributors to this exploration, besides the Smithsonian Insti-
tution, were the University of Michigan, the Audubon Club of Chicago,
and several private individuals interested in the advance of natural
history.

Mr. Xantus, whose explorations in Lower California have been

P REPORT OF THE SECRETARY Al

mentioned in several of the "previous reports, has been appointed by
the government of the United ‘States consul on the western coast
of Mexico; and in this new and interesting region, I doubt not
that, with unabated zeal, he will be able to add much that is
new and important to the different branches of natural history. To
facilitate his labors in the way of making collections, the Institution
furnished him with a full set of articles necessary for the most efficient
prosecution of a work of this kind.

Exchanges. —The system of exchanges still continues to render im-
portant aid to the literary and scientific intercourse of this country
with other parts of the world. It is not confined on this side of the
Atlantic to the United States, but extends to Canada, the West In-
dies, and South America. From the tabular statement given by Pro-
fessor Baird, it appears that during the year 1862 there have been
sent to foreign countries 1,203 packages, each containing, in most
cases, a number of separate articles. These packages were enclosed
in 114 boxes, measuring in the aggregate upwards of 1,000 cubic feet,
and weighing 28,936 pounds. The number of packages received in
return for parties in this country, exclusive of those for the Institu-
tion, was 2,105, which would on an average amount to upwards of
10,000 articles.

The Institution has received on its own account 5,035 articles, in-
cluding those for the museum as well as for the library.

The thanks of the Institution continue to be due to various parties
for their liberality in transporting boxes and packages free of charge,
er in materially reducing the ordinary expenses. Those claiming
especial mention are the North German Lloyds, between Bremen
and New York, the Hamburg and New York Steamship Line, the
Cunard Line, the Panama Railroad, and the Pacific Mail Steamship
Company, all of which transport Smithsonian packages free of charge.
The Adams’s Express Line transmits our packages partly at reduced
rates and partly free. The magnitude of the favors conferred by
these companies may be readily understood by a reference to the
statement made above that the weight of the packages sent to Europe
alone amounted, during the year 1862, to nearly 30,000 pounds.

Labrary.—The library during the last year has continued steadily
to increase, principally by exchanges, but also by purchase. By ex-
changes there have been received 1,211 octavos, 348 quartos, and 52

rf

folios. Of parts of volumes in octavo 2 441, in quarto, 767, in folio,

4? REPORT OF THE SECRETARY.

161, maps and charts, 55, making a total of 5,035 articles. In addi-
tion to these about 500 volumes have been purchased.

A catalogue of transactions and proceedings of learned societies
contained in the library of the Smithsonian Institution was published
in July, 1858, and widely distributed, with a circular requesting that
the deficiencies in the sets might be supplied, and other series be
added to the collection from the duplicates in foreign libraries. This
request has been go liberally complied with, and so many additions
have been made to the collection, that a new edition of the catalogue
has become necessary. This work is nearly ready for the press, and
if the means of the Institution should permit, will be published during
the coming year.

The value of this library will be much enhanced by the publication
of the Systematic Index to all the articles contained in the transac-
tions and proceedings of the learned societies of the world, now in
course of preparation under the supervision of a committee of the
Royal Society of London. This index will include the titles of papers
published by the academies of Russia, Sweden, Denmark, Nether-
lands, Germany, Switzerland, France, Spain, Italy, and the States of
North America. Some idea of the magnitude of the work, says Gen-
eral Sabine, may be formed from the fact, that it begins with the year
1800, and is brought down to the close of the year 1860. The titles
are all in quadruplicate and now form sixty-two manuscript volumes.
It is expected that the index will be completed within the year 1863.
and that it will be published without unnecessary delay. It will be
a work of immense importance to all engaged in scientific pursuits ;
it is difficult to estimate the amount of waste of time and labor of the
student, arising from ignorance of what has already been achieved.in
the several departments of science; and none but one who has en-
deavored in the investigation of perhaps a single subject to explore
the contents of scientific periodicals can judge of the weariness and
discouragements of the search. A copy of this work will undoubtedly
find a place in each of the principal libraries of the United States,
and with the distribution of the catalogue before-mentioned will give
the American student ready reference and access through the Smith-
sonian collection to all the important original papers on scientific sub-
jects which have been published during the present century.

Gallery of Art.—The only additions made to the Gallery of Art
during the past year, have been a bust of Professor Benjamin Silli-

REPORT OF THE SECRETARY. 43

man, senior, presented by his son, and another of General William H.
Sumner, presented by George Wood, esq., of this city.

The Indian gallery belonging to Mr. Stanley still continues on de-
posit in the Institution. It is to be feared that by reason of the
present condition of the country Congress will not think it advisable to
purchase these characteristic illustrations of the aboriginal inhabitants
of this continent, and it may perhaps become a subject of considera-
tion with the Regents to make some provision for the preservation of
the collection in its integrity, since it is possible that the owner may
otherwise be obliged to dispose of it in parts, in order to meet his
private pecuniary engagements.

Lectures.—On account of the uncertainty of the times and the pre-
occupation of the public mind no arrangements were made to furnish a
course of public Jectures on the part of the Institution for the winter
of 1861-62; but the use of the lecture-room was granted, in accord-
ance with previous custom, to an association consisting principally of
persons connected with the several departments of government to
give a course of lectures in aid of a benevolent object. The privi-
lege was granted, as usual, on the condition definitely expressed,
that subjects of sectarianism in religion and special politics should
not be discussed. But in this case experience proved that it is inju-
dicious to allow the use of the room in times of great public excite-
ment for lectures over which the Institution has no immediate control.

The association could not, or at least did not, observe the restriction
as to subjects, and the whole course became an exposition of political
principles which were then under public discussion both in the pa-
pers of the day and on the floor of Congress. The evil of this was
soon manifest in acrimonious attacks upon the Institution by mem-
bers of Congress and editors of papers holding different political
opinions. It was in vain to attempt to neutralize the effects of
these attacks by stating the fact that the Institution ought not to be
held responsible for the character of these lectures; the public could
not be made to recognize the distinction between the lectures given
under the immediate sanction of the Institution and those which were
permitted to be delivered in the lecture-room under the direction of
other parties.

Upon these considerations and those mentioned in the last re-
port as to the inexpediency of frequently opening the Smithsonian
building at night in the present state of this city, I concluded, after
the course of political lectures was terminated, to restrict the use of

44 REPORT OF THE SECRETARY.

the lecture-room exclusively to the lectures given under the immediate
auspices of the Institution. This rule at first gave offence to some
of the friends of the Institution, and was considered very unjust by
another association which desired to give a course of political lectures
in opposition to those which had been previously delivered. It
has since, however, been generally approved by the reflecting
public, and, indeed, must commend itself to all who have studied
the history of establishments under the direction of State or
national governments. Unless they are strictly guarded against the
intrusion of political influence, their permanency and usefulness can-
not long be maintained. So much were the Regents composing the
Board, at its first sessions, impressed with this fact, that, at one of
their early mectings, they unanimously adopted the following sugges-
tion of one of their Meratitioce namely:

‘The party politics of the day, on which men differ so widely and
so warmly, should not, your committee think, enter among the subjects
treated of in any lecture or publication put forth under the sanction
of the Institution. And they would deeply regret to see party tests
and party wranglings obtrude themselves on the neutral grounds of
science and education, endangering, as such intrusion surely would,
the tranquillity of the Institution, disturbing the even tenor of its ac-
tion, perhaps assaulting its welfare, and certainly contracting the
sphere of its usefulness.’’

I need not say to the gentlemen now present, some of whom have
been Regents since the beginning, how strictly the spirit of this reso-
lution has been observed; notwithstanding the members of the Board
from the two Houses of Congress are designedly elected from those
holding opposite political opinions, in this hall the irritations of legis-
lative discussion have been allayed or forgotten, and men of the
most extreme political views have constantly met in this place as ona
common ground of friendly sympathy, actuated apparently by no
other feeling than the desire to guide and sustain the Institution in
its mission of advancing and diffusing knowledge.

To make up for the dissatisfaction which might be felt on account
of the restriction which had been put upon the use of the lecture-
room, it was thought advisable to give in the winter of 186263 a more
extended series of lectures than had been given in the two preceding
winters, but to confine them principally to courses on scientific and
other subjects, which might be of service to those who desired actual

REPORT OF THE SECRETARY. 45

instruction rather than mere amusement; although the attendance
. was not as large as in the case of the single lectures or the more ex-
citing topics of the day, yet it was well maintained and comprised an
attentive and decorous audience.

The following are the courses which were delivered, namely:

A course of six lectures, by Professor Daniel Wilson, of the University
of Toronto, on ‘‘Unwritten History,’’ embracing, Ist, Archeology;
2d, Phy siolog ey; 3d, The Lettered Races; 4th, The Maritime Races;
5th, The Origin of Civilization, and 6th, The Historic and Unhis-
toric Races.

A course of six lectures, by Professor Arnold Guyot, of Princeton Col-
lege, on “The Unity of Plan in the System of Life, as exhibited in the
characteristic ideas and mutual relations of the great groups of the
vegetable and animal kingdom.’’

A course of five lectures, by Professor KE. N. Horsford, of the Law-
rence Scientific School, Cambridge, on ‘‘ Munitions of War.’

A course of six lectures, by Professor John Torrey, uf New York, on
‘Artificial Light.’

A course of four. lectures, by Professor Henry Wurtz, of New York,

‘« Gunpowder.’’

Two lectures, by Dr. Solger, on ‘‘Ethnology.’’

One lecture by Arthur W. Edwards, on ‘‘The Microscope and its
Revelations.”

The courses of lectures by Professors Wilson, Guyot, and Wurtz

will be published in the appendix to the report for 1862, and subse-
quent years.
Respectfully submitted.
JOSEPH HENRY,

Secretary Smithsonian Institution.
FEBRUARY, 1863.

APPENDIX TO THE REPORT OF THE SECRETARY.

SMITHSONIAN INSTITUTION,
Washington, December 31, 1862.
Sir: I beg leave herewith to present a report, for 1862, of the operations
intrusted to my charge, namely, those relating to printing, exchanges, and
natural history.
Very respectfully, your obedient servant,
SPENCER F. BAIRD,
Assistant Secretary Smithsonian Institution.
Prof Josepu Henry, L.L.D.,

Sceretary Smithsonian Institution.

PRINTING.

Tn an appendix will be found a list of the works published in 1862—the num-
ber of pages pzinted, quarto and octavo, greatly exceeding that reported for
1861. Several large works are also in press and will be issued early in 1863.

‘Phe following enumeration will show the number of pages printed during
the year:

Works completed and issued, quarto..... tatceemion pages.. 1,390
OCLAV Ope pelaree ay ep stan epee pages.. 1, 226

——— 2, 616
Woorke Stil mipress;uarto:y/vo-- ene te ecto ec eee pages-. 180
octavoO..--.. ----- o tect ee eee --pages.. 593

ae

T Ota emer ccc cece ee cia Coes ois. S ecareeetoe te ciate eee 3, 389

A complete catalogue of all works published by the Institution up to June,
1862, was issued during the year, and will be found included in the list of
articles published. ,

All the octavo publications of the Institution hitherto issued, and of which
copies enough were.on hand, have been arranged in a regular series, entitled
“Smithsonian Miscellaneous Collections,” corresponding to the “Smithsonian

2?

Contributions to Knowledge,”’ and fill four volumes of over seven hundred
pages cach. An accompanying list shows the contents of these several volumes.

REPORT OF THE ASSISTANT SECRETARY. 47

EXCHANGES AND TRANSPORTATION.

The operations in the department of exchanges, as reported for 1861, showed
a considerable reduction below those of the previous year. During 1862,
however, they have fully recovered their usual magnitude, and while the receipts
of books and parecls from abroad are nearly equal to the maximum of any
previous year, the transmissions have been greater than usual.

The thanks of the Institution and its correspondents continue to be due to
various companies for their great liberality in transporting boxes and parcels
free of charge over their respeetive routes, thereby reducing very materially
the expenses of the department of exchanges. The lines deserving of especial
mention are the North German Lloyd, between Bremen and New York; the
Hamburg and New York steamship line; the Cunard lines, running from New
York; the Panama Railroad Company; the Pacific Mail Steamship Company ;
the Adams’s Express Company; the Iludson Bay Company, &c. ‘lhe magni-
tude of the favors thus conferred may be readily understood by stating that a
single transmission of packages to Germany during the year, through the North
German Lloyd, consisted of 46 boxes of 424 cubic feet, or over ten tons by
measurement.

The Institution is under many obligations for important services rendered in
connexion with its exchanges and transportation, to the Hon. Hiram Barney,
collector of customs in New York, and his assistant, Mr. George Hillier. Also
in San Francisco, to Mr. A. B. Forbes, and Mr. Samuel Hubbard, of the Pa-
cific Mail Steamship Company’s service. ‘The foreign agents of the Insti-
tution, Dr. Felix Fliigel, of Leipsic; Gustave Bossange & Co., Paris, and Mr.
William Wesley, 2 Queen’s Head Passage, Paternoster Row, London, continue
to discharge their duties with promptness and efficiency.

The following tables exhibit the statistics of the different branches of the
system of exchanges:

A.

Receipt of books, &c.; by exchange in 1862.
Volumes :

LAV OR Pes see ate ie oxi love = wa Sie cs 5 era os Shs eal Aud
Wart ocasae pas Sate asiatole a 2 ats) Sov iaidesioye-onel ghee Zine 348
RO Aree psa oS ici aialio c’ay ole e's a aie 'e kate reyaayaiinne: ans aN 52
1,611
Parts of volumes and pamphlets:
eta von =. -)aeeee a alc ce eeeho sraitve Re
etn Os ae eee eee a 8 eae heen cain = = = aa 767
ROMs 25ers Se iere ec eieists wa a c's oc aaa 161
———————=! 3/09
Maps and charta........-. te eas eave eee ae aja, ee 55
Mo talcmee Soe eee INOLe Sto ee Sots 5, 035
CCCI PES MESO Le oo oe Pi in a ao wei oe mo faim wala Braet tech aa aie tla 2, 886

PERCE EAE ren. sxe uereiaanart es atk Sock ec ciate, See bog Ptd, StS es Se a Aas eds S 2.849

48 REPORT OF THE ASSISTANT SECRETARY.

B.

Table showing the statistics of the exchanges of the Smithsonian Institution
wn 1862.

s 24 a 8 3
5 s g b 43 S
| Sl AE bakes eh
Agent and country. eeu 23 2 eS ° 8
SH Dac 2 ioe = a
a g q 24 5 20
5 3 5 B oS
Zi A wi a e
Dr. F. Friern, Leipsic—
Scandinavidejenecsjencsceiee sects ee 1 Te eee ee eels moots
Sweden ce ccjscwcoe Suicmoietemerewate a> 14 Die We werdgert Alte a eieta\e apa Sais ete
INOTWELY)= a <ninieisisie'= Mac cinenie setae 6 LOTS Se mtege ein lens ere arel | eet
Denmarkictesces oles te ect css 13 DONS 2. See aS SoS 2 ere
VUBSID Ges Sereteesooen ate seeieees eeu 37 60! SSeS Sa Oe See seees =
Holland see eee o.oo seoersceaeaee 40 BD cies ctiers haere | eee ete
Germany, oor sivanibiooeaeeniees 262 SA Biliran oleate sas eames
Switzerland secs. ccncsepeceeeemeeee 31 AUT isch secs callh 3 hehe Ce |e pe See
Belgium ....... te te ey eT ee 16 Dees as Py ler | cee

Motel ieisosice eee cde dant 420 585 46 424 | 12,780
G. Bossanan &Co., Paris—
HY aNGOe a catia Sues caresses 25 114 LO 2) Vaseeenies ose | ere ete

talyrestweseccevemectemosceseaee 64 S64) Sais cctect eee roe S505
Spain ssc. Seldioetainintemclavelett stairs 7 PAS sc Lesa ae ccoateen lee eter
IPOLLUCAIE avaceer cueces otee eee 4 5 [oe Sale ee eee | Caer

Total a sssenatseseeceeeee se 189 257 20 183 5, 356

W. Wester, Zondon—
Great Britain and Ireland......... 166 259 16 159 4,100)

Rest of the world ....-. selse meleeeiasetesee 71 102 32 240 6,000
Grandatotal Senteectoosaestennetese 846 1,203 lit 1,005 28, 836

aC.

Addressed packages received by the Smithsonian Institution from parties im
America for foreign distribution in 1862.

Number of packages.

Albany, N. Y.—

New York State Agricultural ‘Society .......2. -beeae a2. ve 28
Boston, Mass.—

American Academy of Arts and Sciences.........-.-+-05-: 106

Massachusetts: Historical ‘Society. 9. ---- =-.<aee ee eee = il

Massachusetts School for Idiotic and Fecble-minded Youth.... 3

Dr Ce aK SO oo aoc tock eR et ee eee 1

REPORT GF THE ASSISTANT SECRETARY.

Cambridge, Mass.—

lative UMC e nes ha Sears alee ci alo state Sei bree. cyfoes a(ate ae
ee NSS oe Oe 5 Se ees aia) o's She aie se sree olasdltelsjersa: aie
HR tege Wee olla ey tte clot oie atejare ee sce: Uso iano a) aya om eretalere xine
PESTO tee LAT OUI Sy 5%, She ao Se Son cy Svan SOD ioe Satnddanon ran ev erat eee

Cleveland, Ohio—
Dirsahms. Newbery 0-5 52% SMe Rem eeieecre ro cieteere cara asiehs ale

Columbus, Ohio—
Ohio States bomd vet Aericulturel:. 2.5. cee clee + shia see
She apg hee ec aes Mahe apg es on sph Atae pte naeircnareNahor a) aparaavste Gicverskcte

Dorchester, Mass. —
Dre darvisies.. - BY ee eye et nic. saacch pe ecethe bya e ee

Georgetown, D. C—
Melia ier eon P SIE So oe ota ae ote oe oes oe eemee

Leon, N. Y—
OU eC CTIO NY, 2 =, 2. ct AEG nian, 2 Tile ajo, =. Nal aians Mts iniieiabaralicforoncroier eles

Madison, Wise.—
PGSTOLICALMOOCICLY 1OF VV ISCODSUNS 22a c.= Spt.m, ain os =,5,cienchehe scat aye
TOT Ole VT SCONSIM cents cnc eer ate) yn st ae nee waned ay were Nie
Montpelier, Vt.—
Dimes bdoraryeor Vermont... 1. «bites es Teese eee ater

Montreal, Can. —
EO TN AWGN re Aes 5 ok cia c'c a oieoin ava opener ete Me vatece

New Haven, Conn.—

ATMEHICAlDy we OURNAl OL MSCICNEG! —5.15 os cine cle kc.c o one Se cw 2

AZO Lege oD) aie) aT ey ayy ae Nene pen a ye oe ced La 2. st ea
New York.—

New-York yceum.of “Natural History =<.) 10). 2 ola ce ek
Philadelphia, Pa—

Paieniceme (Dl OSM MNCA Ua OCLGHVE | onc ticyaiy- hair tS kayo yet
iontomoelozical Society.ot Philadelphia... ..:.-.. 2. gees --
Bennsylvania Institute tor the Blind...) 2-2 es... .cegee see <
Neusat eye Nt 5's shale ~~ acon si oeee ee ete oe
Bera SE CAle 2) yeks ce. ooh tayo Sa ei le so ni em
HENS Jere NEG 8 acc, Salen ai alt Rei el A oe ae lea

Providence, R. 1—
Haters NOde Us lmmtbn. asc ot 5 eRe Ie te cmc a cafe acts

St. Louis, Mo.—

: PmMOoWIs ACHUOMIY Ol: SCIENCES so w'alnio a atsiais aa slave we a eee des
3 cece

49

12
a0

v

3

~
eo

126

Go

Or Qn

06)

5O REPORT OF THE ASSISTANT SECRETARY.
Toronto, Can.—
Canadian Institute........-.. ial Mu 0 asain meena ial iii tage ae 4
Washington, D.C—
Topographical Bureau .....-----+-0+--0+ eee eee eee e ee eee 228
United States Coast Survey <oi5 ae! 4 a miere wie ee eres eee 50
United States" Senate. .< <<<. ols ccc cape ne oo 2 ae eee eer, «-- 250
Gen.A.A, Humphreys. omar <9 <p 20500 2 oe win ninnm mpi neice 75
Ota evecatcouse uted Bile o1s'9 o1acaielg ares eee pee eee 1,944
D.

Addressed packages received by the Smithsonian Institution from Europe for
distribution in America, im 1862.

Albany, N. Y.

Albany Institute......---- fespe alec.
Dudley Observatory ...---- .----+ ----
New York State Agricultural Society -
New York State Library. ..---...----
New York State Medical Society -....
New York State University ......---.
Professor James Hall........- ean ae

Amherst, Mass.
Amherst College.....- so00 nace plain oie
Annapolis, Md.
State Library-..-20+ eennes cee aaelauar
Ann Arbor, Mich.
Detroit Observatory
Dr. Brunnow...---- -----+---- ele als
Mr. Watson... 2. cecces woce vee aie
Augusta, Me.
State Library -..--.- ene none cone cone
Baltimore, Md.
Maryland Historical Society -..-..---
Peabody Institute
Dr. J. O. Morris .... -200 coon cone --e-
Mr. Ubler.... scoees enenee cone concer

Blackwell’ s Island, INO) Ge
New York City Lunatic Asylum......

Number of
packages

o>

mnrnre~a _ Ea on

=

Bogota, New Granada.

Sociedad de Naturalistas Neo Grena-

Cinder a Cee cs coeatecta cancers ae

Boston, Mass.

American Acad'y of Arts and Sciences
American Statistical Association .... .
Boston Society of Natural History...
sowditch Gibranyae «eaeieeleres stele « mata
Historic Genealogical Society---.---
Massachusetts Historical Society. ....
Prison Disc‘pline Society -...-...--.
Public Library ..... pisteiateiet ie a's Seats
State Library scemnslseiaom sls = alateers een
Boston Journal of Natural History ..
North American Review.........---
By; Alger. amc ame inaaeiee ead
DrMIBIGwerlacreseebaan Motdisiela.® = staleietste
AA Goulds oe cape came sin seme tan
Drop. VatV AS eeteettaltee's ep isleiete aaleiots

Dr. Wilsonicdalsientee salaeia cmleneene aa

Brattleboro’, Vt.
Vermont Asylum for Insane .......-
Brunswick, Me.
Bowdoin College ..... Mince cosises cate
Historical Society of Maine. .-......
Mrs. Parker Cleaveland .......ccee.

Burlington, Iowa.

Historical and Genealogical Institute -

packages.

Number of

_
—
=

2

a
for)

me DO Oe OR Re ee

ei

REPORT OF

THE ASSISTANT

SECRETARY.

51

D.—Addressed packages received by the Smithsonian Institution, §c.—Continued.

Burlington, Vt.
University of Vermont...........6-.
Cambridge, Mass.

American Association for the Ad-
vancement of Science...... acamines
Cambridge Observatory ......-.-----
HAT VAG COMET Ce alc dasiteracs soneme
Editor of Astronomical Journal......
IPTOLESSOL Ws AP ARSIZ con ceclsonaltaance
GRP BONG see coos bees Coca wceaincioe
IPTOLESSOL Els J. Clarke cnsccces soucee
rH DA GOUlda cco. sceche ccac vocecs
Professor Asa Gray - 2.2. coos cose cee
PMT ST Oletatet a aetale lel slaie) = ainlale|ainial o sie
Professor Julegy Marcou.....-.. ee---s
Crbp NOL -teceseceeces cotetesnee
IPVOlesSOLID. LOlCE 4s cnawee)aassteccous
I PCHUD ED eeicisccrwscticl sete oeeeies mans
Dee WWORCOSLELE po n.ciSieisinin.c'e © niu afop seni
TOR VITA mem icinieipis nisin sea nin'mlawid's

Chicago, Ill.

Academy of Sciences...e0+ 20. secee.
Mechanics’ Institute...-..00. scene
ColiJ#D:; Graham's. BeAsis.s ceocsss

Chuquisaca, Bolivia.
University of Chuquisaca............
Cincinnati, Ohio.

Astronomical Observatory.......-.--.
Historical and Philosophical Society
Of OM sect tamate) ow elel teelele'i gael costs
Mercantile: Librarycociseiecss secclees-
Obsenvatoryetaesocssonswsee ns cm
Western Academy of Science.........
Editor of the Dental Register of the
ES eee ote aisteie elaine ea oie teeta mor mle
Protessor Mitchell ccmepete-icesca.

Clinton, Ne Xe
Drs CO! EBS Letters ceenepeeah ons aaa

Columbia, Mo.
Geological Survey of Missouri........

Columbia, Pa.

Professor §. S. Haldeman...... Weieiebis
Dri MIGISBEID CIs an nals ania tw ain’ halen ea

Number of

whe Ort

TO bo

~

_

roe eS

ee

er

packages,

Cilumbus, Ohio.
Ohio State Board of Agriculture.....
Stateslibraryiices csinjcocice coemesicon

TCOMDCEQUICTECAU Rp este ao oo slubulcle nein '=
WVepSUivalibere merets aletemetam sale antes

Concord, N. H.
New Hampshire Asylum for Insane-.

New Hampshire Historical Society...
State Library ....0+ eevee ate eeiate me ete

Davenport, Lowa.
Right Rev. Henry W. Lee..........
Des Moines, Lowa.
State Library scence sess prema eteiaia
Detroit, Mich.
Michigan State Agricultural Society
Dorchester, Mass.
Dri Wo Tarvisensts eae soaeceee eee
Easton, Pa.

Dr. B. Clemens..... caaniaee aa marraee
Professors). Ele Comin es smeciecemaane

Erie, Pa.
17s OMMEGC ees sapdiena ce eieeeeee
Fall River, Mass.
NielsvATh Zen eee steacatteen Swais/es cletais

Farmington, Conn.

Hidw. NOrtonbcssteeemeacetenae conce-
Frankfort, Ky.

| Geological Survey of Kentucky.....

State Tabrary, \ a 23s scbiorswebasack

Mr: Shotinetens nesses oneness cae ees

Gambier, Ohio.

Menyon Collece wcesevasasuns. cdueys

Number of
packages.

Rm boo oo

Ore

ee

me or 0O

52

REPORT OF THE ASSISTANT

SECRETARY.

D.— Addressed packages recewed by the Smithsonian Institution, §c.—Continued.

Georgetown, D. C.

Georgetown College
Dr. A. Schott

Hanover, N. H.
DartmouthyGollegesss#ssss2s2e2- 2
Harrisburg, Pa.

Pennsylvania State Lunatic Hospital --
Huvtombibraryssesoescsecs ac ceene se

Hartford, Cann.
Hartford Society of Sciences_-....----
Historical Society of Connecticut-.--.

Stateplitbrany sees eee eases
Young Men’s Institute

Havana, Cuba.
Observatoire Physique et Météorolo-
DIQUE ae sane tee eee eee
Real Sociedad Economica -......----
Hudson, Ohio.
Western Reserve College......... os

Indianapolis, Ind.

Indiana Historical Society_-.......---
Stateshibrangeesacsseeccsesssecee ss

Lowa City, Towa.

Plate OL Lowa ease eee sees s eee
State University of Iowa:...-..--...

Janesville, Wis.
State Institution for the Blind-....-.
Jefferson City, Mo.

Historical Society of Missouri_...----
Statemnbranyesteeess S22 oo Sse seen

Kalamazoo, Mich.
Asylum for Insane-...... eee eee
Lancaster, Pa.

Thomas C. Porteresssesei 202022 ae

1
i

Co OU

oe

co

| IT. Apoleon Cheney

Lansing, Mich.

Agricultural’College=aeesese os. sees
Statednbrary asso lsecccase ete See

Lecompton, Kansas.

| Statewhibrary Sess ccs ose coe cee

Loon, N. Y.

Louisville, Ky.

Colonel hong. oso5--- eee ae
Professor J. Lawrence Smith

meee ee

Madison, Wis.

Historical Society of Wisconsin
Skandinaviske Presse-Forening -....
State library: <2 225. <c-= 5-5 seer
Wisconsin State Agricultural Society~

Montpelier, Vt.
Staten rayne sea sees eet

Montreal, Canada.

| Natural History Society.--.----.--.

DraSmallwood .2o-co.esseeeemaes
Nantucket, Mass.

Miss; Maria; Mitchell sooo s2=-seee— ==
New Brunswick, N. J.
Professor) Gabe Coolea oma aaien ete
New Haven, Conn.

American Journal of Science......-
American Oriental Society---------
Yale College

WP: Blake... ss o2 eee eee
Gy Jke Brush: (= 2 eee ee eee

ee ee eee

|| Professor’ J: D. Dana 222o2 22 eset

‘Professor EH: hoomissasceesneeeesene
Professor Sillimane 2soee ae eee aen eee
Professor W.D: \Wihitheyes=o.2——='

New York, N. ¥.

American Agriculturalist .......... E
American Ethnological Society......

Number of
packages,

ees

bo Go

Oe

bo bo

~

REPORT OF THE ASSISTANT SECRETARY.

53

D.— Addressed packages received by the Smithsonian Institution, &c.—Continued

packages.

Number of

New York, N. Y.—Continued.

American Geographical and Statistical

MS CIEIG LY gieeystexs cya iat atermmici= TesfestaySicaj jets 2
‘American Institute. —25-—.----------
ACtOTAINDIATY 22 seen oe see ecieein io
Mercantile Library Association--...-.
New York Historical Society --..-.--
New York Lyceum of Natural History.| 6
University of the City of New York--
New -York Dental Journal.....-.----
Harmer and Mechanic 2/2. --.-.3-
New York Journal of Pharmacy---..--
CempROV Ge aes aeie sen Seams eae nich oe
Ghai esy np BIACl= aan aemicinisia cine oka.
PeaMeinield ssases ss sess ccce esse et
Drebrapets =e sos soa eee
Dre Ce BATON aes oa se mcs Sie mic ata"
Mhomas) Woleston) 222 aes <<< ee
Professor Wolcott Gibbs..... Dita
S. Hestrantescece ooo a oe ieee area
ee Gane Leese Se ee es
Mrbanlanes S52 So ecsincinio cain ona ame
Charles BY Norton--2. 2-2... via oso
Baron’ Osten-Sacken 2.222 .ce 054 -
Protessom Redheldi:ss-sssccsssancac
TOL CRS CLAW AVI Seen totes ie ayers ae

qo

BPE TWN ND HEHE WW HEE EP NNN DOHwWRDS

es

Norwich, Conn.
MiTOCK Wellye Sanemameee mic ceeete mes 1
Olympia, Wash. Ter.
Territorial Library .....--... See 3
Omaha, Nebraska.
Fermitonal Library ssssceesesa<e =e 3
Oswego, N. Y.
Mrmeumpelly=--25..ce0 aosoae Seta ey
Philaddphia, Pa.
Academy of Natural Sciences.......- 142
American Philosophical Society....-.
Central High School of Philadelphia.
Beankdinv Institute’. - .--pemeaesacnelc
Geological Society of Pennsylvania -.-
Geological Survey of Peunsylyania --.
Historical Society of Pennsylvania...-

Mercantile Library Association.......
Pennsylvania Hospital for the Insane-.

I

~

Pennsylvania Institute for the Blind.
Wagner Free Institute...... Pte estate

CHK HE Oe NRO

—

Philadelphia, Pa.—Continued.

American Journal of Dental Science-
Dental: Cosmoskesse6 oS eee
John Cassinwese-ssece ei einiefacre eee
I ACTS oto a at rey cli
Drghi DS Cope ass a6 ssoemeceoeeee
BS Dnrand ge. 2 aan oe a
DrjHermannaa. cate eeeeee eee eee

Esa. SIeunin CRS Sees a ete 8 pa

Professor F. L. Otto Koehrig ....---
Drs visaac heats 5. oe eee See

Dri Jost phy leidy = s=sse--e-e eee eee
Georce Ord: e-2es eos eee
By Peale 2 a2 aoe ae ae eee
Mrs: Av. Mig omass 2-6 peeeceiea ne
Professor, Wagner =.55 24622 eSeee
Mire Wetherelli t= S252 see ae
Portland, Me.
Neal Dowie iu. ooo 5c5 Soe eee
Princatcn, N. J.

College of New Jersey-..-. memteieea
BrofessomAl Guyot. 2) sees eeeee ee

Providence, R. I.
Brown University -sa-<seeeeeosese
Rhode island Historical Society...
State btbrary oss s-sos se ceeS ene
Rio Janeiro, Brazil.
Instituto Historico Geographico Bra-
sillero. 22 2<- 32 See oe
Rochester, N. Y.
Hon. Lewis H. Morgan....... Rees
Rock Island, Ill.
Dr. John Rittles .....-.- poanmoeces
Sacramento, Cal.
State Library ss=--— et tatoos
Salem, Mass.

HSSeX IN Stitlte sas esis seine oes

Number of
packages.

—_
Be ORR ROWE NH DH ee be

yee

hm bo

oF

REPORT OF THE ASSISTANT SECRETARY.

D.— Addressed packages received hy the Smithsonian Institution, §e—Continued.

Number of
packages

Number of
packages

San Francisco, Cal. Washington, D. C.
California Academy of Natural Sciences} 31 Pe ane sere oe taeDy i
logical Survey of California.....- 1 oe SL a ele Taal
Geolog National Observatory....+----..-.. 87
; Surgeon General U.S. Army-------- 1
St. Louis, Mo. Topographical Bureau--.---------- 1
Deutsche Inst. fir Bef. von Wiss. Pee ae “BACT Ee abe ak
S id Gewerbe: 22222) sees ce 3 Yes ee MoT 5515553 Se el
Kunst un eee 0) Gl Patent @iice toe ane a eae 133
Geological Survey of Missouri. -...-- 2 War Department 3
St. Louis Academy Gf SClENCeS=en ees 105 Colonel vA bent (sea) aah oe 2
, Lionis UpiVversity,-<.-=2.-.000==-- Dot ll a eaccar widl AI AISA Se Tid ike e E
Bt. ‘ Ber 1 Professor A. D. Bache...--..----2-- oF
Dr. George Bernays------+----+ eseee Professor. S. Hy baird 2-. 2 cose2eeceee 6
Dr. George Engelmann........2- .--- 8 W. D. Breckenridge --.--------<--- 1
Dr. Hammer -.------+------------ : Major Wmoryssco-ce see aaaee comes 1
Dri Baven 2 ess-2- 2 owe ee seeanes 1 J. Ferguson 2
DrvAlibert CalNoch= 2425-222) 3- -5--- 2 TG J), DLA COEL SEE giiare naa 1
Die Shamardes - 50% a ecde cop 7 ttn uPA) (lite Clon ob wl
G.C. Swall ° 9 Captain J. M. Gilliss, U.8. N-_------- 37
9 aN ee OW cAesase srt aranrss sch Captain H. J. Hartstene, U.S. N...-- 1
; : UD Gas hs Sane alee eee eet ee 1
Santiago, Chile. Professor W. E. Jillson......-..-<-- 1
Ob t 1 Professor W. R. Johnson...-...----- 1
BEBYATOnyE aise See er eee J.C.\@) Kennedy2 tts 242 Beano: 3
University of Chile.-...---..------ 9 ieutenant’S) P2lLecess2 eee ee 2
H.(Bi Meekiisacb 2 es onieee iets eeeh 3
Springfield, 1U. Drad: SoNewbhettys: gon See 1
' WW: Rigget: nee ee
State Library OCS aie c Eee ea 5 = ence ew eaonan cote Scene ;
Rev. L. P. Esbjorn ....-.2.----------- 2 Hon. WH Seward 220s See 1]
- We Smyth!i 22 Sle bibs So eee 1
Stockton, Cal. Profi(W:iStimpson i. Losesgaeei aoe! 9
Hon. Charles Sumner ....--------- 1
Asylum for Insane...-.-.----+----- Ll Ey Uilico, so, ea ee 2
t da West. 2
Toronto, Canada Wes Waterville, Me.
Board of Agriculture of Upper Canada- 1 Waterville College --.--...--....- 2
Canadian Institute....-..------ece.. 1
Westchester, Pa.
Pres Nese Dr. W. Darlington .... ...c0.-0--- 1
Geological Survey of New Jersey ----- 5 ;
State ‘Library Ten ee ea 5 West Point, N. ¥.
\ NoProfessor Bailey G2 sc2ceee Jane ga 1
Utica, N. Y.
Worcester, Mass.
American Journal of Insanity.... .... 3 reo : : :
: : erican Antiquarian Society ...... g
New York State Lunatic Asylum..... : State Lunatic Hospital ...-...-...- 1
Valparaiso, Chile. Vor Pa
WEG:
Dri TyAgReid': sack. eoth. shes 1 Rev.| Mr. Zeiglers. 24 soncae5-se0—2 1
Motaliof adGresseSeanclsesictea'= sa ao lerin sinininia iaie is we Gee Meese aes 273
Total Of PALCCIS= - a. cena aaa = oe eqn eae nee a eae ne se eee cee melaeets 2,111

REPORT OF THE ASSISTANT SECRETARY. 55

MUSEUM AND COLLECTIONS.

As might have been expected, the receipts of specimens of natural history
during the year past have been materially curtailed. The entire number of
donations in 1862 amounted to 124. The number for 1861 was 157, while that
for 1860 was 404. Much of interest has, however, been received from different
quarters, and the aggregate would have been more considerable if all the col-
lections made in the Hudson Bay region by Mr. Kennicott, and other gentle-
men, had not been kept back in consequence of the Indian outbreaks in Minne-
sota during the year.

Mr. Kennicott spent the spring and summer of 1861 at Fort Yukon, on the
Yukon river, making large collections of specimens. He wintered on the Rocky
mountains, at La Pierre’s house, and made a visit to Fort Simpson early in the
spring. News received there from home determined him to return to the United
States, and he reached Fort Garry the beginning of September, arriving at
Chicago in October, after an absence of three years and a half. A detailed
report of his expedition will be prepared by himself, and submitted hereafter.

The gentlemen of the Hudson’s Bay Company, of whom mention has here-
tofore been made as aiding him in every way, have continued their kind offices.
To Governor Dallas, present governor of the Hudson’s Bay Company, Gover-
nor Mactavish, Mr. Bernard R. Ross, Mr. Lawrence Clark, Mr. R. Mac Farlane,
Mr. W. L. Hardisty, Mr. James Lockhart, Mr. C. P. Gaudet, Mr. James Flett,
and others, the thanks of the Institution are very especially due for such aid to
Mr. Kennicott as ensured the success of his expedition, and without which
he could have accomplished little or nothing.

To most of the gentlemen above referred to acknowledgments have been
made in previous reports for valuable contributions of specimens. Collections
made by them in 1862, having been packed with those of Mr. Kennicott, have
not yet arrived, but are expected early in the year 1863, as, at the last advices,
they had reached St. Paul.

Mr. John Xantus, so well known on account of his scientific researches in
California, in connexion with the Institution, has just entered into a new and
entirely unexplored field, promising the most important results. Having been
appointed United States consul at Manzanillo, he left New York on the 11th of
December, and is doubtless now at his post. With their usual liberality, exer-
cised so often before in the interest of science and the Smithsonian Institution,
the Panama Railroad Company and the Pacific Mail Steamship Company gave
free passage to him and his extensive outfit.

IDENTIFICATION OF SPECIMENS.

Much progress has been made by the various gentlemen mentioned on page
62 of the last report in identifying and labelling the collections of the Institu-
tion. It will not be long before the greater portion will be thoroughly worked

p, and a general distribution of duplicates accomplished. No new collections
of any importance have been given out, although Mr. Cope expects to take up
the North American saurians belonging to, the Institution with the view of pre-
paring a report on the subject.

Dr. Allen having completed the examination of the American bats intrusted
to him, as far as his professional engagements would allow, has returned the
specimens, and deposited a report on the subject, nearly finished, and to be
hereafter completed by him. Dr. Wood has also returned a portion of the col-
lection of Myriapoda. Dr. Slack has sent back the collection of monkeys, with a
catalogue of the collection. Mr. George N. Lawrence has labelled the entire

56 REPORT OF THE ASSISTANT SECRETARY.

collection of humming birds, amounting to over 150 species. Professor Agassiz
has determined and returned the collection of Kehini.

Mr. Gill has continued his examinations of the fishes of Cape St. Lucas, col-
lected by Mr. Xantus, and published many new species from them.

DISTRIBUTION OF SPECIMENS,

The distribution of duplicate specimens has been continued as fully as time
and opportunity would allow. Several large collections of mammals, birds, and
eggs have been sent off, together with a considerable number of sets of marine
shells. Dr. Foreman has been engaged for some time in making up the duplicate
Unionidae into series, of which about twenty sets will soon be ready.

WORK DONE IN THE MUSEUM.

The mounted mammals and birds which occupied the Museum Hall at the
beginning of the year have all been identified, and to most of them neatly writ-
ten labels have been affixed. This portion of the work will be completed as
soon as the clerk assigned to the duty can accomplish it. All the specimens
have been carefully examined, and those attacked by insects have been re-
moved and baked or exposed to the vapor of benzine. A few skins have
been mounted of species possessing a particular interest.

“The collection of skulls has been cleaned and rearranged in the southeast gal-
lery. The series of rocks, and in part that of minerals, have been placed on
their proper shelves. Nothing further has been done with the shells, the col-
lections in this department not having been returned by the gentlemen having
them in charge.

All the miscellaneous boxes of specimens in the Institution have heen un-
packed and their contents assorted and distributed. All the crude material in
the building has thus been put into condition for examination, and given out to
investigators for arrangement, with the exception of a portion of . the fossils and
the general ethnological collection. ‘These will, however, all be unpacked and
examined in the ensuing year.

The progress of work upon the collections already in the Institution at the
beginning of the year was much interfered with by the necessity of receiving a
large number of specimens formerly belonging to the National Institute, and
sent from the Patent Office (where they had been stored) by the Commissioner
of Patents. Much of this material was in an exceedingly damaged condition,
requiring instant attention and much labor to preserve it in even tolerable con-
dition.

The cataloguing of specimens in the record books of the Institution has been
carried forward during the year by the insertion of nearly 10,000 additional
entries, many of them covering each a number of specimens. The present ag-
gregate of entries is about 75,000, embracing at least 500,000 or half a million
of specimens. When it is remembered that none of the plants, and insects, and
but few of the fishes and invertebrates, have yet been recorded in this way,
some estimate may be formed of the extent and value of the material for re- -
search in charge of the Smithsonian Institution.

or
~]

REPORT OF THE ASSISTANT SECRETARY.

Table showing the total number of entries on the record books of the Smith-
sonian collection at the end of the years 1861 and 1862.

1861. 1862.
PSL COINS ATS ss CUI Se tes ten ete ele = 4,459 4,759
Mammals. < eamo< cece nn en macnn anne emcee one mane sewen- 5, 550 5,900
SES Ta pS ate te nec et seater lemme 23,510 26, 157
Rephilessasenea—— fas eet orl lesa medi )o 6.088 6,311
Fishes..-.---------- ------------------------------------ 3, 643 4,925
PBs irc Kean ONL eee ee ete ett tea ete afte ete atete etm ta lalate [aia 4,83 6, 000
OD pt ECGS UI Sentero eet eon aso eles one ee neni wnt een ln ete ia 1, 287 1,287
BIOTA TACT Ss ets estes eet eee nen er lel ml lea al 9,718 10, 000
es radia ss oi ry ae Tier ea ln Rh a he 1, 800 2,675
BEI Sega eas el heels een erent ele tees me imtoo 1,031 2.100
PVN 0 Steet ee elle era el ell me 3,580 3,725
BGhmoOlosieal specimens sos] ola cee mmm a nein = 550 825
PESTA Ea ee eee em ct es caliente sl lle sosoos 105 109
Totalo-= =~ Se ee eee tetas folaieteioleraierete stata Sele
66,075 74, 764

LIST OF DONATIONS TO THE MUSEUM IN 1862.

Agassiz, Professor L.—Skins and eggs of birds from Labrador: specimens of
ITaemuton.

Akhurst, James —Bat and crustaceans from South America.

Barnston, George —Birds, fishes, &e., from Lake Superior.

Beadle, Rev. H. R.—Box of minerals.

Beitel, C. G.—Minerals and furnace slags from Pennsylvania.

Berthoud, Dr. E. L.—Minerals, fossils, and skin of Lagopus leucurus. Pike’s
Peak.

Bertolet, Dr. P. G—Sections of wood of trees of Pennsylvania.

Bickmore, A. J—ULiving Pheton flavicauda, from Bermuda.

Blackman, Mr—Series of specimens of prairie chicken or pinnated grouse,
from youngest chick to adult. Also skins of other birds, insects, eggs,
&e., from Ilinois.

Bland, Thomas——West Indian shells.

Brandt, H—Nests and eggs from Fort Riley.

Brush, G. J.— Box of minerals.

Buckner, Dr—Set of models of edible fungi, prepared at Hildburghausen.

Cardeza, Dr—Series of choice minerals from Pennsylvania.

Carlton, U. S. A., General J. H—Skull of rattlesnake, from New Mexico.

Carothers, Rev. A. G—Collection of reptiles from Martinique.

Chapman, N. H.—Box of birds’ nests, from Ohio.

Cochran, T. G—Eges of Night Heron.

Cook, Prof. George II—Fossils of New Jersey.

Cooper, Wm.—Fossils from the Isthmus of Panama. Cast of Megalonyzx
bones.

Couper, V.—Skins of Aegiothus, from Canada.

Cowles, P. M.—Insects from Cumberland Gap.

Dawson, Prof. J. W.—Postpliocene fossils, from Canada.

Dow, Captain J. M—Mammals, birds, and other animals, from Nicaragua.

kins of birds, and various alcoholic specimens, collected at sea between New

York and Panama, va Cape Horn.

58 REPORT OF THE ASSISTANT SECRETARY.

Eaton, Dr. H. K.—Specimens of Gryllotalpa.

Edwards, A. M.—Mounted infusoria from Washington Territory.

Egleston, Thos.—Minerals from Massachusetts.

Elliot, D. G.—Four skins.of European birds.

Feilner, Lieut. John. —Mammals, birds, &c., from Fort Crook, California.

Foreman, Dr. E.—¥ossil tracks of animals from Maryland.

Forns, R. M—Two skins of Chordeiles minor, Cuba.

Geoffroy, Mons—Collections of birds from Bogota.

Gibbs, George.—Shells and fossils from Washington Territory

North American antiquities. (Deposited.)

Gilliss, U. S. N., Captain J. M.—Package of poisoned arrows brought from
the Amazon by Lieutenant Herndon; Coral from Agatha’s Bank.

Goss, B. F.—Nests and eggs of birds, from Kansas.

Gundlach, Dr. J—Box of Cuban birds.

Gurley, R. R.—Golden eagle in the flesh, shot near Washington.

Habel, Dr. H—Minerals from New York Island.

Hayden, Dr. EF. V—F¥ossils from Maryland and New Jersey.

Hayes, Dr. I. [—Esquimaux dresses and other curiosities; Birds, mammals,
and rocks, from North Greenland. :

Heermann, Dr. A. L.—130 species and 250 specimens of Humming birds; Vireo
barbatula, from Florida.

Hepburn, James.—Birds’ eggs, from Pacific coast of North America ,

Hubbard, Samuel—Thirty species of Californian fishes.

Hunt, U.S. A., Captain E. B.—Hippa, from Key West.

Kennicott, R.—Box of eggs and skins of mammals and birds from the Yukon

river.
Lawrence, George N—Hylophilus, from Guatemala; Mounted Macrorhamphus
scolopaceus.

Lea, Isaac.—Box of Unionide.

Leonard, J—Minerals from the Rocky Mountains.

Lewis, James —Large collection of land and fresh-water shells of United States,
including selected series of Paludina.

Lewis, Joseph S.—Coleopterous insects, from United States.

Lowerce, T., per J. J. Major —Pityophis, from Guadalaxara.

MW Kenzie, J—Birds from Moose Factory.

Major, J. J—Kges of Pandion, from the Similkameen.

March, W. T.—Series of birds of Jamaica.

Matthews, G. F.—Fossil shells of New Brunswick.

Meck, F. B.—Fossils from Maryland and New Jersey.

Mendenhall, Kirk —Egegs of birds and fossils of Indiana.

Moses, Dr. S. G.—Living Duck-Hawk, hatched in Connecticut.

Newton, Alfred —Thirty species of eggs of Arctic European birds.

New York; Panama R. R. Co.—Series of fossils from Isthmus of Panama.

Palmer, Dr. Edward—Shells from Acapulco and San Diego.

Paris; Mus. d’ Hist. Nat.—Series of serpents from various localities.

Parkinson, D. F.—Mammals, birds, &c., from North California.

Pease, W. H.—Shells from the Sandwich Islands.

Philadelphia Academy of Natural Sciences—Specimens of Rissa and Otus.

Pierce, Warren.—Asellus, from Ohio.

Poey, Prof. &—Vishes of Cuba.

Ried, Dr. A—Skeletons, skulls, and antiquities of Patagonian and Araucanian
Indians. ;

Remhardt, Dr. J—Box of European birds.

Ross, B. R.—Bale of large skins from Prince Rupert’s Land.

Russél, Dr. W. H.—Seven species of Himalayan pheasants.

i

REPORT OF THE ASSISTANT SECRETARY. 59

Samuels, E.—Series of infusorial slides.

Schenectady ; Union College-—Box of minerals.

Schiffmann, R.—Insects from Missouri.

Schmid, Dr. H. E.—Reptiles, &c., in aleohol, from Japan; also living Megalo-
batrachus, or Giant Salamander.

Sclater, P. L.—Seveuty-five species of Jamaican birds.

Scott, Ansel —Indian relies from Bradford county, Pennsylvania.

Stimpson, Jos—Copper spear head and other relics.

Stone, C. J—Box of minerals.

Swan, James G.—Skins of birds, crustaceans, shells, &c., Straits of Fuca.

Swift, D.—Minerals and Indian remains from Pennsylvania.

Thomsen, J. H.—Skeleton of sperm-whale porpoise, Nantucket; Echinarachrus,
from New Bedford.

Tolman, J. W.—Birds’ eggs from Illinois.

Totten, General Joseph G.—Coral from the Tortugas.

Totten, Colonel—F ossils from line of Panama railroad.

Tryon, George W—Type specimens of new shells; box of Unionidae.

Van Cortlandt, Dr—Fishes from the Ottawa river.

Washington; National Institute—Four cartloads of miscellaneous specimens.

Whittlesey, E.—Coal from Ohio.

Williamson, Sergeant J. J., (company E, 2d New York artillery.)—Snowy
owl, shot near Washington.

Willis, J. R.—Shells, fishes, birds, eggs, &c., of Nova Scotia.

Wingate, J. D.—Box of Helices, from Pennsylvania.

Wood, Dr. Wiliam —Living Duck Hawk, from Connecticut; also skins of birds,
eges, and Indian remains.

Woodworth, Dr. J. M—Shells, eggs, &c., from Lowa.

_ Wright, W. W—Fossil wood, found five miles from Alexandria.

Wurdemann, W.—Shells of Florida, (deposited. )

Wyrick, David.—Bones of man and animals from ancient graves in Ohio.

LIST OF SMITHSONIAN PUBLICATIONS DURING 1862.

Discussion of the Magnetic and Meteorological Observations made at the
Girard College Observatory, Philadelphia, in the years 1840—1845, by A. D.
Bache, LL.D. First Section, Part Il. Investigation of the Solar-Diurnal
Yariations of the Magnetic Declination and its Annual Inequality. June, 1862.
4to., pp. 28.

Discussion, &c. First Section, Part III. Investigation of the Lunar Effect
on the Magnetic Declination. June, 1862. 4to., pp. 16.

Discussion of the Magnetic and Meteorological Observations, &e., continued.

— <=
Second Section, comprising Parts 1V, V, VI. Horizontal Force, Investiga-
tion of the Ten cr Eleven Year Period and of the Disturbances of the Hori-
zontal Component of the Magnetic Force; Investigation of the Solar-Diurnal
Variation and of the Annual Inequality of the Horizontal Force; and of the
Lunar Effect on the Same. November, 1862. 4to., pp. 76.

Monograph of the Diptera of North America. Prepared for the Smithsonian
Institution by H. Loew. Part I. Edited, with additions, by R. Osten Sacken.
April, 1862. Svo., pp. 246, with fifteen wood-cuts and two plates.

Synopsis of the described Lepidoptera of North America. Part 1. Diurnal -
and Crepusecular Lepidoptera: Compiled for the Smithsonian Institution by
Jobn G. Morris. February, 1862. 8vo., pp. 376, and thirty wood-cuts.

Museum Miscellanea, or Aids to the Labelling, Cataloguing, and Recording
of Specimens. Svo., 1854—1862, pp. 48. ‘This contains— ;

1. Abbreviations of names of States and Territories of North America, for labelling in-.
sects, shells, &e.

2. A series of small figures, from 1 to 1643.

8. A series of medium figures, from 1 to 2747.

4. Aseries of large figures, from 1 to 2599.

5. Blank check list of specimens.

Catalogue of Publications of the Smithsonian Institution, corrected to June,
1862. 8vo., pp. 52.

List of Forcign Institutions in correspondence with the Smithsonian Insti-
tution. 1863. Svo., pp. 40. .

Results of Meteorological Observations made under the Direction of the
United States Patent Office and the Smithsonian Institution, from the year
1854 to 1859, inclusive; being a Report of the Commissioner of Patents to the
Senate, at the first session of the 36th Congress. Vol. I. 1862. 4to., pp.
1270. (Vol. II is in press.)

Annual Report of the Board of Regents of the Smithsonian Institution,
showing the operations, expenditures, and condition of the Institution for the
year 1861. 8vo., pp. 464. -

WORKS PARTLY PRINTED IN 1862, BUT NOT COMPI.ETED.

Meteorological Observations in the Arctic Seas. By Sir Francis Leopold
M’Clintock, R. N. Made on board the Arctic searching yacht “Tox,” in
Baffin’s Bay and Prince Regent’s Inlet, in 1857, 1858, and 1859. Reduced
and discussed by Charles A. Schott, Assistant U.S. Coast Survey. 4to., with
one Map.

Notices of Ancient Mining on Lake Superior. By Charles Whittlesey. 4to.

Check List of Minerals, with their Symbols. Prepared for the Smithsonian
Institution by T. Egleston, Jr. 8vo.

LIST, OF PUBLICATIONS. 61

Synonymical List of the Coleoptera of North America, with Descriptions of
New Species. By John L. Le Conte, M.D. 8vo.

Bibliography of American Conchology. By W.G. Binney. 8vo.

Synopsis of North American Air breathing Shells. By W.G. Binney. 8vo.

Synopsis of North American Vivipara, &e. By W.G. Binney. 8vo.

WORKS CONTAINED IN THE FOUR VOLUMES OF MISCELLANEOUS COLLECTIONS,

Smithsonian Miscellaneous Collections. 1862. Vol. I, 8vo., pp. 732. Contains:
(19.) Directions for Meteorological Observations ; (87.) Corrin, Psychrometrical Tables4 °
and (31.) Guyor, Meteorological and Physical Tables.

Smithsonian Miscellaneous Collections. 1862. Vol. II, Svo. pp. 692. Contains:
(27.) Boor anp Morrit, Recent Improvements in Chemical Arts; (115.) Proceedings
Board Regents Smithsonian Institution in relation to the Electro-magnetic Telegraph ; (53 )
Srantey, Catalogue Portraits North American Indians; (108.) Barro, Catalogue of North
American Birds; (49.) Barrp anp Grirarp, Catalogue of North American Reptiles—Ser-
pents; (128.) Check List Shells, North America; (34.) Directions for Collecting; (137 )
Circular to-Officers H. B. Co.; (139.) Instructions for collecting Nests and Eges; North
American Grasshoppers ; and North American Sheils; (158.) Morgan, Circular respecting
Relationship.

Smithsonian Miscellaneous Collections. Vol. III, 8vo., pp. 766. Contains: (102.)

Osten SACKEN, Catalogue Diptera North America; (118) Morris, Catalogue Described

Lepidoptera North America; (136.) Le Conts, Classification Coleoptera, I; (117.) Cata-
logue Pubtications of Societies in Smithsonian Library.

Smithsonian Miscellaneous Collections. Vol. IV, 8vo, pp. 752. Contains: (134.)
Hacen, Synopsis of North American Neuroptera, and (133.) Morais, Synopsis of North
American Lepidoptera.

LIST OF METEOROLOGICAL STATIONS AND OBSERVERS

OF THE

SMITHSONIAN INSTITUTION

FOR THE YEAR 1862.

BRITISH AMERICA.

3 3 i ay
3 = emai
5 "Eb S oo
Name of observer. Station. 3 5 ; 3 ae
- = = = 3s
= z = & |°3
° n
z E im Siveahe
‘ Shall aay Feet.
Acadia College...... »».-| Wolfville, Nova Scotia. .......+.- 45 06 64 25 O51 AG eee 10
Baker, J. C.......00 +.» | Stanbridge, Canada East.... ....- 45 08 73 00 aka call lleteiate 12
Clarke, Lawrence, jr..... Fort Rae, Great Slave Lake ......|ccsecs eres |oeeses - Joas er bsiaig decir 9
Craigie, Pe Varlereresiteiels Hamilton, Canada West. oie 43 15 79 57 asec UR ae ae 12
Delaney, Edward M. J....| Colonial Building, St. John’s, New- 47 35 52 40 170051. Baty dee 7
foundland.
Fleet, Andrew.......+.-»| Fort Norman, Hudson’s Bay Ter- 64 00 124 00 200) Wiener 5
ritory. ,
Dickson, Walter.........} Little Whale River, Hudson’s Bay OOS | lcleteratelererete 1 eee ee ll
Territory.
Hall, Archibald, M. D....| Montreal, Canada East......... 45 30 73 36 D7 OAT oetereisiell tance
Hensley, Rev.J M...- King’s College, Windsor, Nova 44 59 64 07 S00 aereevecice 3
Everett, Prof. J. D..... Scotia.
Kirby, Rev. W. W....+-+.| Fort Simpson, Hudson’s Bay Ter- 61 51 DLS Ti icrele sisters “Deeieisteietate 4
ritory.
Magretic Observatory....| Toronto, Canada West...... «+... 43 39 79 21 +108 Aven cee reda
Mackenzie, John........| Moose Factory, Hudson’s Bay Ter- 51 15 80 45 | .... 60. Beta Re) meee
vitory.
Phillips, H ......-...+...| Niagara, Canada West..... eeaisie 43 09 79 20 DIO) | A cecewres 3
Rankin, Colin..... see. Michipicoton, Canada West..... 47 50 85 05 ay ha ae Nearer atete 8
Richards, Thomas........} Kenogumissee, Hudson’s Bay Ter- 49 50 S400 OO OKT telererereieter a
ritory.
Smallwood, Dr. Charles..| St. Martin, Isle Jesus, Canada ies] 45 32 73 36 WS VA eteialere 9
{ |
CALIFORNIA.
ees g 2
5 z teenie
Ss & & es
Name of observer. Station. County. 3 § 2 Ss =
re 3 = B [ss
5 3 B a 55
z E be eS wal ie
° / ° /
Ayres, W. O., M. D.......| San Francisco.| San Francisco.| 37 48 122 97 12
Belcher, W. é Neva! vepeveieveeete Marysville ....5) Yuba, once. 39 29 121 30 12
Dunkum, Mrs. eozabetu's Honcut. .<.... WUbaAgsceysjenes| 09 20 121 30 12
Hays, W. W., M. D. ..| Presidio of San | San Francisco 37 48 122 26 3
Francisco,
Logan, Thomas M., Ms D..| Sacramento. ..} Sacramento...) 38 35 121 28 12
SmithoML Dii.eeie ecw anys Spanish Ranche| Plumas........ 39 56 120 40 3
Whitlock, James H........| Meadow Valicy) Plumas.......- 40 20 120 15 1

* A signifies Barometer, Thermometer, Psychrome-_ P signifies Psychrometer.
ter, and Rain Gauge. R signifies Rain Gauge.

B signifies Barometer. N signifies No instrument.
aT signifies Thermometer. ¢ Above Lake Ontario,

METEOROLOGICAL OBSERVERS.

o>
oo

COLORADO.
— cea 3 =
4 | 3 ae
z Ep Bg. 183
Name of observer. Station. County. 5 5 3 g & 2
s Ss = 2 Ss o
= gS = 3 3 2
v
Z is 3 5 Z
Sid ea Feet.
Ellis, Dr. Wm. T.... ......| Mountain City.| Arapahoe.....} 39 35 105 40 | 8,000 | T. we... 1
Stanton, Frederick J ......| Denver City, ..| Arapahoe.... «ve Sen: « wees 4
DISTRICT OF COLUMBIA.
Mackee, Rev. C. B.... fi) Georgetown ...| Washington. .. 38 54 GROIN piarelater ote) (ir Lye) Ler ex cia) fades
Smithsonian Institution,...| Washington Washington... 38 53 77 Ol GOP AN e(rersieint ole
CONNECTICUT.
Case, Jarvis..... + steer [MC ANILON | wicks oie iets Hartford....... 42 00 73 00 OOM |ipdee Rs veteratet| end
Harrison, Benjamin ) eee Wallingford. ..| New Haven. . 41 27 72.50 Taio |eAeueeterarere| tueene
Hunt, Rev. Danpelerece tac POmMErets tears ais) Windham. ... 4l 52 72 23 DO Meu teAciere ater (meee
Johnston, Prof. Jobn.......| Middletown. ..| Middlesex... 41 32 72 39 UFSPEIMAT Satreers 12
Learned, Dwight W .... Plymouth. ... | Litehfield .... 41 40 MSeOBEe||loeamaiet Ely eieteralete a
Leavenworth, D. C........| New Haven. ..| New Haven...| 41 18 72 56 AQW | (Bewlstisnet 3
kockwell, Charlotte. ......| Colebrook.. ..] Litchfield. ....| 42 C0 73N06)" lteiee,ceahi| CDs weenee | 12
Yeomans, William H......| Columbia. ....} Tolland. ...... 41 40 72 42 ws iDawareraternte je
DAKOTA.
Hill,G@ D.. Siai(siejels
Lawson, George W- siersietele Yankton covoe jecccccsscccceees| 42 51 STI | ierereieisiarss)| sieleielesioveie 4
Williams, Herbert a...
FLORIDA.
|
Dennis, William C.........]| Key West. ...| Monroe, ...... 24 33 81 28 16 | BaToR.s/. 12
Magnetic Ob- | Monroe. ...... 24 53 81 438 6 Balab se 5
Ferguson, G. F. .ceoe. + Been tGRVAICe
Oltmanns, J.G..... eee Paey|
? West. |
ILLINOIS.
Fe VEO sae “2g Tiskilwa ......| Bureau........| 41 15 89 66 550 | N..seeee| 12
Babeock, E . Remeneleits Riley..... Seis oo PLIMECELONTYicctercte’e 42 3) &8 20 760! WPTOR Poe 12
Bacon, E. Bienes -»-.-..| Willow Creek.| Lee..... afeneiarars 4) 45 SS5008 |) 1,040) |) Nevis ole
Ballou, N.E.M Dees .....| Sandwich .. DeKalb iecie cs 41 31 &8 30 Gye) | UUeliiaiag 12
Bandelier, Adolphus I°.,jr..| Highland ...... Madison, ..+... 38 45 &9 46 slcieie «l(a eulven bes lL
Blanchard, Orestes A ..... Elinira ..0. 000.) Starks. cevee 41 12 90 15 yakeretets 5
Breeds Mi Als wias/e cies =- Peoria) ences Peoria ........| 40 38 89 46 TER setae 2
Brendel, Frederick, M. SD ..|Peoria’s;.. <cs.| Peoriascsa ces: 40 43 89 30 Asravews 12
Brookes, Samuel.. oececees| Chicago..,.....| COOK..cceeees. 42 00 87 30 sy sveatete 12
Bryant, C. H.,............| North Prairie..| Knox.........| 41 08 90 06 N.wssses{ 6
Byrne, Arthur je ae :
BoesJames H.. ee CHICAGO . voces. | COOK cece coe [soe scccvs|sccveccess|eveecees| BeDecse-| 10
Cobleigh, Rev. Nels.E . ,D.D | Lebanon......| St. Clair.......] 3% 37 89 56 500 | B.T.R..| 6
Crandon, Frank...........| Batavia , ane Warerctelra cle 41 52 88 20 GE{3 9 )) Akavagosa 1
Dudley, a naaiy ri] Jacksonville... Morgan .......| 39 30 90 06 G7 Ole DR eee. 12
Grant John. wee : a ‘ 2 « :
Grant, Misa Ellen. Er o Manchester ...| Scottsecsccces: 39 33 90 34 683 (ASAIO SOC hae 123
Griffing, Henry...........-| Willow Hill....| Jasper ........| 39 C0 &8 CO scon|p Wisidoase 5
Little, J- Thomas .....+...| Dixon. ........ LE. cccecece..| 41 45 SO Tes eS SeralsteeltNisictete's 7
Livingston, Prof. Wm... Galesburg .....} KKMOX . see cces|cocces veers toro lnocooond ARte ana 12
Mead, 8. B, MD se tes.ecect Agusta Hancock « ....| 40 10 “91 00 203) |PRTPY 12
Meeker, Ralph [Eipiseleteleisie'eis Dongola..,....} Union.... ....} 37 26 CORTE le oteeteiers|| Lice ce aie 3
Merwin, Mrs. Emily Bi. Ottawa.......,| La Salle. se.... 41 20 88 47 500 | T.R.... 12
O’Donoghue, WO Ens gage PONCE cigoedgdalp Who “aadodasned 41 54 87 38 650 Bee se 2
Olds, Warren etelstats ..| Albany....«..-} Whiteside..... 41 40 90 16 600 | N.seoes.| 10
Patrick, Dr. John ae oe : ;
Baker, Nathan T'........ } Belleville......| St. Clair. ose. 38 29 90 06 GOOM | Bai iee ney) se
Riblet, J. H.....seeeeee0s-| Pekin ... ....| Tazewell......| 40 36 8945 Wieecee »| Bed. R..| 12
Rogers, O. P.andJ.S......| Marengo ......] McHenry......| 42 14 88 38 842 | B.T.R..| 12
Tolman, James W.vees cece Winnebago De-| Winnebago.. 42.17 89 12 900 "Bet .R..| 1
pot.

*Above low-water mark at Quincy,

64

METEOROLOGICAL OBSERVERS.

INDIANA.

. o nf
3 = a =
S co = Es
a a 8 2
Name of observer. Station. County. 3 5 is E e 5
a a a 5 °
BoE ene See
ae E a a a
Sea © al Feet.
Anderson, Henry H........| Rockville......| Parke. sssceces 36 00 87 09 1,160 Nits 0h ll
EVO G Kerns taupetarataterstaiecien: sibyvellensiae.| Shelby) tees «siete 389 00 SBOO) il hreht ste ce) Wueravecatate ll
Chappclismith, John ...... Ww Harmony.| Posey ......... 38 08 &7 50 PAU learn caoen (ie
Dawson, WANNA. cars weiss «| CAGIZ « -atenicee- | ELONLYireeceis aie « 3900 85 20 TCBO Sy, | pleniltis wietee 6
Dayton, James H..........| South Bend....| =t. Joseph..... 4} 39 &6 07. €00 eB. ate.< {2
Haines, Jolinces.<... eoonee| Richmond. ....] WAYNE «vcenne 09 52 BANOO) | fetate calelouy | elziet La staiss 12
Larrabee, William H......| Greencastle ...] Vurmam...... 39 30 e6 47 BOOS SAIN cya o-cicts 1
Rambo, Edward B........| Richmond.... | Wayne... os. 39 47 84 47 SCO? | ste St 5
IOWA.
Real, Mrs. Celia. ..........| Grove Hill: ....| Bremer....... | 4245 | 8712 |eeceeess| Tessnese| 2
wc ae ear ' Davenport...:.] Scottsssessee| 41°80°/|-) 90.40 |» 737. |rAccsieavleae
Collin, Prot. Alonzo. .....| Mount Vernon.| Linn.-... ....| 42 00 QU 00 occ oe eini| We stamaeies en
DEening, DiSia- cae yasiee one INdependence.| Buchanan). »<s4||.scs sos ax |leeeeuadeises| pees cee | "Dy Gretateletate 2
Wont ly sis drag onaue Waterloo ......| Biack Hawk...| 42 30 QOD | oor epde lp iw ensistactere tage
Farnsworth, P. J., M. Del LLVONS 4s cies coc} Clintons see cee 4\ 50 £9 10 AGUS Ts Bi eaters mmc
Foster, Suel. Sale eiaieiejeree os a\s)( MLUSCAINE. vise MUSCATINE: «cox 41 26 S200 Vee eepaisials IielNjereclefets aula
Tiorr, Asa, M.D...........| Dubuque. . Dubuque ...... 42 30 90 52 656 | Piva laleisie.e 6.) hex
ERCSON GAN dies VEPs aleraice a)! LaVONSe sep can il MGI tts oes ne. 41 50 90 10 AU aT Rveeants 8
Leonard, Wm. P...........| Kossuth...... | Des Moines.... 41 Ov DUS Nl ercuntetan punter eens 3
ney Townsend.....,.| Pleasant Plain.| Jeflerson......| 41 07 $4 34 $50 DR... | 12
NeVoy, Franklin, M. D.. 2} : - le
PEGS Epes i Algona........| Kossuth. ......| 43 01 94 04 | 1,500 | pe ces tl ae
MeCready, Daniel .........| Fort Madison..| Lee .... ......| 40 37 SID 2B i lee raerere PR scene le
Millard, Andrew J.........| Sioux City.....| Woodbury.....| 42 33 96.27 | 1, 258F a Pee ee ere
Parvin, Prof. Theodore S..| Iowa City .....| Johnson.:.... Sajeieneisin{scercd|leleieisieley= sfalalsieatetal lesa etniataved Imm
Sbeldon, Daniel.+......... | Forestville ....| Delaware...... 42 40 915 popcool) 2s adaowe 7
Ufford, Kev. John .........) Museatine.....| Muscatine... 41 25 92 02 586, GAN sac ee
Wheaton, Alex. Camp.....| Independence .| Buchanan..... 42 25 $2 60 cavieae MDRR Neos 9
KANSAS.
Drew, Fred. P..M D.,U.S.A.| LONE GH Eyrever ae || | aalstetatahatetetonemsrnts 39 00 96930) 415.300) | SLs ene 3
Fuller, Arthur N ..........| Lawrence.....| Douglas .... ..| 33 58 95 13 SiO) ae Reveste tere 6
Goodnow, Isaac T.........| Manhattan ....| Riley.... seaee- 39 13 96 45 | 1,000 | T.R.....} 12
CakteldeiG@ ales oi eicsets sess s|| PLUM POLI chic ceni||scieeveisieeeie bie steloye'| e/aierexsin)ureuyai| ain erate che 'sjasl fietaictakere rete] | MUCR Master 1
Scott VAMEStetancctesice ssl) Gardner sascha Johnson s.cccc.|ooceee allele he odo flevere.eseteternl| MELvare eaten 1
Scymour, E. W., M. D. seiele UN CHON Olt yc 3] MO) VIS) islet esis 38 58. 96 32 260) 1) Tiatewunia 3
Shaw, M.......+.++...e6--| Leavenworth..| Leavenworth. . 39 18 $4 32 SGT vere cretetet 4
KENTUCKY.
Beatty. iO} iesteatistieeneise | PD ANVillOneeseae|| OVI ertn caterer 37 40 84 30 900) Bis eyes 8
Mathews, Jos. McD., D.D.| Nicholasviile ..| Jessamine ....| 37 58 84 18 D800) | TA aie werstes fp
Mattison, Andrew..... «es.| Paducah ......| Mt. Cracken...| 37 00 SUEZ. ssc ceheayentt mNietemtelae 5
Savage, Rev. G.8 >M.D...| Millersburg..,.| Bourbon ...... 38 40 84 27 804 | B.T.R.. 3
Swain, "Jobn, M. Dies ..».| Ballardsviile...] Oldham .... .. 33 36 85 30 461, WA aces 1
Voodrufi, EN Sccet acces MOUISVINIE: ice | Letersonune scene 38 22 B5TIB! | |]ia sie: = oip'e!| bp Aleverssle eis
Young, Mrs. Lawrence....| Louisville.... | Jefferson......| 38 07 85 24 LOT WAT sietoietas i Pn
MAINE.
Brackett, George Emerson.| Belfast. ......-| Waldo. .sccveee 44 23 GONO8) iNieteetet oie! leek ste neal melon
Dana, Wm. i),............| North Perry ...| Washington...| 45 00 67 05 a pats i
ate ies ; Pembroke .....| Washington... 44 53 67 15 Bi aeles
ON Elise. 4 Baldwinsville..| Worcester ....| 4237 | 7205 | 847 | BoT.....| 1
Gaines; Rev. As, Ga ces scree (Bethel eececcen| OxXtOrd ee. s oc, 44 20 70 52 CoO Ma ERA es. 2
Gardiner, R. H...... Gardiner ......| Kennebec .&.. 44 40 69 46 FOP Bry Ree
Guptill, G@. W..eeeec0-e0e,| Cornishville ...] York ..... 2...) 43 40 70 44 SOON UR real le
Moore, Asa P....c06 oovee-| Lisbon........| Androscoggin... 44 00 70 04 130) | MDCT A ys eee
Bankers dln D tears ssisiate es «n|//SLOUVEN) a cic Washington...| 44 44 67 50 OOH Avreweese tte
Pratt, J. Frank, M.D......; New Sharon...| Franklin ...... 44 37 FOROS Pl heteiietere e1| NT evetainerate 2
Reynolds, Henry ...eeeee... East Wilion....| Franklin ......| 44 44 TOL eit e'sist || Niesetegatetalsl melee
Van Blarcom, James ......| Vassalboro’? ...} Kennebec.....| 44 28 GO ATi alosaise ws) Be Latent inate
WVIES ty SUA ay=c.0/e(uisinre restate f CXOLDISIN wtelats'ate'el|/ MORI Geeluci ecciciary 43 40 70 44 WO4-- | N Re aria ates,
* “Wilbur, Benj. F.....e.000>| Dexter... 0...| PenobsCot.....| 44 55 69 32 7100" >| TORRE eee nde

METEOROLOGICAL OBSERVERS.

MARYLAND.

é g ie
= = 3 rs
S Ei 5 = 2
Name of observer. Station. County. 3 Ee fi S ES
= = ‘Ss = & 5
= z = en ae 2
° o ma °
Z E a 5 2
Sil oy gil Feet.
Baer, Miss Harriott M......| Sykesville.....| Carroll .... 00. 39 23 76 57 (O00! WP Res!) ae
Bell, Jacob E.........+.e..| Leitersburg....) Washington .. o9 35 MOO al iefein's: sveisies| edesibiciereie 6
Dutton, P:of. J. Russel.....| Chestertown,..| Kent ....- 89 12 EAD ail eae tate ayet | AS here tone 10
Goodman, Wm. K. ...... Annapolis. .... Aune Arundel . 33 59 76 29 20) | MAR si. 12
Hanshew, Henry E........ frederick . Frederick .... 39 24 Vile Oden I tsfalayey aceCeyn| lic A\chsteresie 12
Johns, Montgoniery, M. we Agric’l College. BrINGeG COTE ELS Piajeratarasielett |laretoseiiela(etetsl li fe(siaincevsiei||/ AN plelele islets 3
Lowndes, Ber jamin O ....| Bladensburg...| Prince George’s}| 38 57 76 58 WSL Le Sere 10
Stephenson, Rev. James...| St. [nigoes ....| St. Mary’s..... o8 16 76 41 Aa be Atersjeiecievel |r iilco
MASSACHUSETTS.
Astronomical Observatory.} Wil'iamstown..| Berkshire ..... 42 43 73 13 725 Beak. 1
Bacon, William .... ......| Richmond .. ..| Berkshire .... 42 23 320 F | PLST9O I Reese. 9
Brownsi Nathan Wiresscrsscc| “LOpSficld’. oic0.,|(MoSSCX 72.010. ~ cei] sine oe Mateiniecoreaaiel | eleleiensaieiel|eea eerste 6
Davis, Rev. Emerson .. ...| Wesifield..... Hampden ..... 42 06 72 48 LEO GAC recta sie 12
Falicn. ODM isis, cers Lawrence, ....| ESSeX ...00 ens: 42 42 aL UL LSS iA eteretoae 9
Metealf, John Geo., M. D.. Mendon...... | Worcester, .... 42 (6 WOES | Salaosrtet ||| Lic Mtere e's 12
Prentiss, Henry C., "M.D ..| Worcester ....] Worcester.....| 42 16 71 48 S26 me eat enterere 12
Reynolds, Orrin A.........| Randalph......| Norfolk ...... 42 10 71 C0 SUL | Nisicctarete ]
Rodman, Samuel........-- New Bedford ..| Bristol .....0.: 41 39 70 53 £0 A eisisis 12
Snell, Prot. E.S..... eeees.| Amberst ......]| [fampshire .... 42 22 72 34 0 ian ea ctarerereta 12
MICHIGAN.
Beene AR Ma 222 t] Marquette.....| Marquette.....] 4632 | 8741 | 630 | A.ses..] 12
Coffin, Matthew......3....| Otsego........| Allegan ...... 42 28 €5 42 662. | N.wve-s- 6
Crosby. J B...-....se.eee.| New Buffalo...} Berrien. ..... 41 45 &5 46 61 Beeler ro
Pitcher, Zena, M.D. 22.0. Detroit ...-..| Waynes... 42 24 82 58 OTe le Aisiecteralote 4
Schetterly, Henry R.......| Northport .....| Leclenaw ..... 45 3 5 DAES Ileravereistavara| eNistatsieiere 7
Smith, Rev. L. M.S.-...-| Mill Point.....) Ottawa........ 43 06 SOM | | tereiststetere i beacon) jo
Sireng ila Meee celaseittee ciel MOUANG) jecwes, | OCLAWASS~ «sve 42 00 85 00 GSO | Dei sre< 1
Van Orden, Wm., jr.......| Clifton. ......| Kcweenaw.... 47 U0 &8 00 800)» eee li
Walter, Mrs. Octavia C. Cooper........| Kaiamazoo... 42 40 5 20 COD ARS sere |e UL
Whelpley, Miss Florence E.| Morroe .......| Monroe........ 41 55 €3 23 DOO) fF Re reterers in
Woodard, C. S...........| Ypsilanti. ....| Washtenaw.... 42 15 §3 47 Aes | ANsieretetere 12

MINNESOTA.

a

Garrisons|Os Pcijascciececis
Paterson, Rev. A. Bell, D. D.
Rigas. Reva Se Rie: seea ave
SiN TENT YA Ln csiscc. Yeleters «i
Thiekstun, T. Foo... .sc0ce
Wieland, Gsiee<ceces) ses

St. Cloud.......
St) Paul vices
Pajutazee .....
Forest City.....
Hastings. .....
Beaver Bay....

Stearns.......

RAMSEY . vecees
Brown) ..0« ese»
Meeker..
Dak Ota’ rerereierr
TGAKE sieisteraisivvelsis

45 45
44 33
45 (0
45 45

AT 1D |

94 23
93 05
94 00
94 00

==
Jt

Tye
T.
as
as
The
B.

Rei aieee
R vse
it ode
R eee.
Tey stota,s,

WO O1Gs sd 3 t

—

a ST ne seen yIEEtEEE EEE ESSERE

MISSOURI.

Bowles,S. B.,M.D... ....
Christian, John. sadoouaeoar
Engelmann. George,M. D..

Fendler, Augustus .. .-..-
Lunemann,John 158.5...
Maxeys W. Bccccucs ssc
_ Myers, J. Hose cress
RiiVaGeOrre rR caivieiajeyecinis (es
Tidswell, Miss Mary Alice..

Fn aU UNE RSEDEEE ENE E EES REESEREERREREERRR

58

Greenfield ...
Harrisonville...
St. Louisic.e.:
Stt LOuiIsi.ceee:=
St. Louis......
Paris
Kirksville......
Canron..
Warrenton...

se teen

Dade.....

CaS wveciassee|.

St. Louis......
Sts LOoWisiace.
St. Louis..
Monroe,.
Adair. ....seeee

eee

teeee

LEWIS. cece ccce|ece

PRED eons

38 37
38 40
39 30
40 33

38 27

93 41 | 1,800
vata seca lanes sees
9) 16 470
6015 475
92 U0 700
92 50 | 1,000
segraneslsenasees

N..

N

—
T

A.
B.
A.
ake
N.

T.P..
ee,

|

ee

WonrrKWURK®w

—

METEOROLOGICAL OBSERVERS.

NEBRASKA.

rn

3 3 : s
B 2 3) les
ae iS oe =p
Name of observer. Station. County. 3 2 ; a 5
; i . é = 8
x a abe s eo
Se iS & a °
o 7 oe
Bowen, Miss Anna M. J....| Elkhorn City ..| Douglas.......| 41 22 96 12 cecvecs}| 12
Evans, Jobn........es. 0005] Fontenelle.....| Dodge ....0500. 41 31 96 45 ane ceehs 6
‘Hamilton, Rev. Wm........ Bellevue...ccjes| SALPYsccsee)'s) of) 41 08 95 59 =) Real averss | trl
White Bela icici ce me) sie. XC OSNAy qevslcie (sil CASS nase eicieiietete/s 40 51 95 54 Sehatefetete 5
NEW HAMPSHIRE
Brown, Branch...... ..e..| Stratford .....-| Coos .... sees. 44 08 WS, 7) 1000) | Reese le
Chase, Arthur..............| Claremont.....] Sullivan....... 43 22 72 21 53 Bete we
French, [saac 8. Seve Dis Loudon Ridge .| Mermmack .... 42 20 71 25 ATO | Teaco iaetil
Nason, Rev. Pligsy soc c2.4| Exeter macs Rockingham... 42 58 70 55 Hoon | aise Dereerate 10
Odell Mleteherkicjres:sjcisie/eie\s}|, SUCIDUTMEN (ae ain COOS) cislsyahulsiataiate 44 23 71 06 00), |} GBI Etec 4
Pitman, Charles H......... BOs Barn siad) Beiknap......-| 43 38 TAL DM NetoomoatNals aoogont,
NEW JERSEY.
Cooke, Robert L ...... Bloomfield.....| Essex....-s....| 40 49 74 08 AO) 9) ANS crraleierasl Readies
Rhees, Morgan J., M. dD. Mount Holly. 2 | Burlington 's:cja<sillse%sicsisieleinsalecrdsjeeiera| eau Bite! Q
Thompson, George W....-.] New Bunswick| Middiesex.... 40 30 75 31 SOM eaters 12
Whitehead, W. A......... | Newark.......| Essex... o.cse 40 45 74 10 SOM hibits 12
Willis, Oliver R...........| Freehold......| Monmouth ....; 40 15 CAROLS AN eietars)ats/| i Ltuocaimiateiet 2
NEW YORK.
»
Bartlett, Erastus B ........| Vermillion...,.] Oswego....... 43 26 77 26 Sou, || ye essreicis 12
3eauchamp, Wm. M......| Skaneateles...| Onondaga...... 43 00 76 30 932 Beye se 1k
Bowman, John.......e.s. | Baidwinsville..| Onondaga..... 3 04 GHAI | cis'eisicreceiel|| dtc uawere 12
Cowing, Philo.....+...+..-| Seneca Falls...| Seneca....... 42 54 76 51 463i /Borlacists 12
Dill, Joon B......-+00.....| Auburmn.. . Cayuga. cae eeve 42 55 Te Deyo Naonoanos|patcsaace —« 12
Denning, William H....... FishkiliLanding Dutchess ...+. 41 34 74 18 2) | (Bowe Res |e
mee Dons ' Rochester .....] Monroe.......| 4308 | 7751 | 516 | B.T.R..| 12
GrezOsyiSOissinaiceesiecleree sl] LMCTESA aieiersieieei|) VCMCTSOM nicesine| | 44 12 75 48 SOO! see eeperayetel ele
Guest, W. E ..c. e000 ooee| Ozdensburg....| St. Lawrence..| 44 43 75 37 DE PSS Donec 12
Heimstreet, John W......./ Troy ...... seee] Rensselaer. .....:. Awa 73 37 D8) | GAkeacs 12
Hibberd, A. A.......ceee0e| Hermitage.....) Wyoming...... 42 09 ABV UAY \evejereletere|| 2 un Meters 8
Holmes, Dr. B. S......006.| Wilson ........| Niagara ....e.- 3 20 78 56 250)" 5]! erica 12
House, John C eeee.sses-s.| Waterford .....| Saratoga...... 42 47 73 39 Oey |e Aveutarerate 12
Howells: RODGLE ce teteteteict oci[| DNICDOISs slcicineren OD Aree cic. alnte 42 00 OR S2e | leueeyorerteted hielceciaietelers 12
EVES; Williaa raciearcsstecelalere’e!|| UAL! -o/sc/ejoferct|| LINE Wh itetareyoleraysiale 42 50 78 56 600 Aire teieains 12
Mack, Revi Br. si se sctasiece si) MIAtDUSI e,cereis| AGES Ieislevclerne ae 40 3 74 02 Oder AB er dren kererail 0 id!
Mackie, Matthew .........| Clyde..........| Wayne........| | 43 10 77 10 ANOs)|\ Baiiwect 6
Malcom, Wm. S...-. ..00.| Oswego ...cee.| OSWEZO ..s00s 43 28 76 30 250 BieUy rere |e wll
Mathew-, M M.,M. D....] Rochester.....| Monroe........| 43 08 77 SL B2Oy UWA derailer ele
Monroe, Prof. A.T .......| Fordham ..... | Westchester... 40 54 73 57 47 Bey ers 2
Morris, Prof. Oran W......| New York.....| New York..... 40 43 74 05 95 VAC ercieteretel melee,
Paine. Hi) M.; M.D icces,cece || OUMCOM s eleios'e si" OMCIDA se ncrcsieeli) uae OS 75 15 G00 LVR Re 12
Russell, Cyrus EH..........| Gouverneur....| St. Lawrence.. 44 19 LOMOONa leetaretare Bem ierier ele
Spooner, Dr. Stillman.....| Wampsvilie ...] Madison. ...... 43 04 75 50 500 | T.R “lc 12
Sylvester, Dr. E. Ware.....| Liyons ........| WAYNE .... 000s] -v2--+ cee aisle veiisletete|| aereteiotetere!| Mle koma areata 8
Titus, Henry Wm..........| Bellport.......| Suffulk ........] 40 44 72 54 UD) eal PAS petstetete 6
Wadsworth, A.S ......... Henrietta .....| Monroe........} 43 06 77 51 600 | B. T.P 6
Wakeley, Charles C., Ruth- | New York... .| New York. ...| 40 44 73 59 AD} Avvsverecrs 10
erford’s Observatory.
White, Aaron ....se.ee00.| Cazenovia. ....| Madison......| 42 55 Mora6) || 1260) | Ac saree 12
Willis, Oliver R ...........| White Plains...| Westchester....) 41 05 Sy ADI | alate) eietajsl| Mle staeieicine |) 19

METEOROLOGICAL ‘OBSERVERS.

a
~]

OHIO,
7 o n
3 3 ¢ 13.
= a Ee Eres
5 5p = go
Name of observer. Station. County. = = 2 § eR
3 3 S E | 83
o D> wa a
z E = ea
ehuale Sa Feet.
Welshfield ....| Geauga........| 41 23 SUF OS Lele ciel mele
Adams, DP ye. st Marietia.......| Washington... 39 25 81 31 GOs ee uticie. 7
Atkins, Rev. L. 8S. .| Saybrook......| Ashtabula..... 41 52 81 Ol GSO dy scatsree 8
Benner, Josiah F..........}| New Lisbon ...}] Columbiana...} 40 45 80 45 961 | B.T.R 12
Clark, Wm. P.....00 eeee0-| Medina........| Medina........ 41 07 8147 | 1,255 | A. ... 12
Colbrunn, Edward... .....| Cleveland . Cuyahoga.....| 41 30 81 40 665. | Discone.| 12
Cotton, D. B., M.D... ~ .| Portsmouth....| Scioto .........| 38 45 82 50 523) 1 Be DeaR. | -'3
Crane, George W .ccvecvene| Bethel....0000./°Clermonts.cece 39 00 84 00 Ooo) ED sku. 1
Davidson, Wilson .........| Freedom ......| Portage........} 41 13 8108 | 1,100 | B.T.R..| 5
Dille, Israel.....ses0ce0...| Newark .......| Licking ....... 40 07 82 21 825) i Divseeens 10
Shin Case “++ 2) Austinburg....| Ashtabula.....] 4154 | 052 | 816 |T.R.....] 2
Fraser, James...,.0...2s..| Little Hocking.| Washington.... 39 25 81 00 welotoniat) Ni stseistalefsl acl:
Hammitt, John W.........| College Hill...) Hamilton......] 39 19 84 96 SCOR IRIN GE serate 12
Harper; George W........ | Cincinnati.....| Hamilton......| 39 0 84 27 *500 | As. cccesc]’ 12
Haywood, Prof. John......| Westerville....| Franklin......- 40 04 83 WO |... eses| Accvevee 12
Aull, F. Circe ath caved Dallasburg..... Walren .aseces 39 30 84 31 S00) Tt Nicceicae «s 11
Huntington, George C .....| Kelley’sIsland.| Erie.... ....+- 41 36 82 42 Hoe NB DR] 2
eae sua MSM sine ' Cleveland.....| Cuyahoga......] 41 30 81 40 643 | B.T.R 12
Ingram, John, M.D...... | Savannah......| Ashland. o... 41 12 SATS | TO9E WP Asserasjere i) 12
Jerome, A. B...... suesseee| New Westheld:| Hood’. : sss. 41 13 83 49 602 | mw. Resse 9
Johnson, Thos. H.........}| Coshocton.....| Coshocton..... 40 18 81 53 OD) TWA siisiere.« 2
King, Mrs. Ardelia C ......| Madison.......] Lake.......-..| 41 50 &1 00 G20NT Ranker 12
McClung, Charles L.......) Troy...+..seee./ Miami... .-| 40 03 84 06 | 1,103 | B.T.R. 12
MeMillan, Smith B....... | East Pairfield.. Columbiana . baal oe eve B0K4S) S152) As arco 12
Newton, Rev. Alfred.......| Norwalk......-| Huren..ees cece 41 15 82 30 miatelcisieo le etelseciacih ke
Peck, Wm. R.,M.D......| Bowling Green.| Wood .eseseeee 41 15 83 40 LOOM Bo Deakeec| 12
Peirce, Warren ...........| Garrettsville... Portage........| 41 15 81 10 SOON I ecereteiereis 8
Phillips, R C. and J. Ii....| Cincinnati..... Hamilton....., 39 06 84 27 0410 | B.T.R 12
Pillsbury, Mrs. M. A........| East Cleveland.| Cuyahoga...... 41 31 81] 38 659 BAT. 10
Smith, C. H., M. D........| Kenton......../ Hardin ....0.0. 41 30 84 41 Sisie}sisje 5) hey Liste 4
Thompson, Rev. David....| Milnersville ...| Guernsey..... 40 10 81 45 9
Thompson, Rev. Elias.....| Croton.........| Licking........| 40 13 82 38 12
Tappan, BliT ............| Cincinnati...,.) Hamilton......| 39 07 84 27 12
Trembley, J. B., M. D.....| Toledo... ....| Lucas.....<e. 41 39 82 32 i2
Ward, Rev. L. F. Riaio(e cleisieieiel| SI EVIILE etojeie: e'wieie |) MRCCITIA ce eiaisiein 39 59 81 47 7
Warder, ake JEN sane Cincinnati.....| Hamilton ..... 39 08 84 35 iL
Williams, Prof. M (Giese, | Mlebatia sce escd Champaign....| 40 (6 83 43 12
Wilson, Prof. J: H.........| College Hill....| Flamilten...... 39 19 84 26 iL
Young, Prof. Chas. A.... }
Share Bl Wrensieveehoeieiee iss | ;
Pettingell, W.....,..se-. }| Hudson,.......|/ SuMMit....0..| 41 15 81 24 | 1,137 | B.T.R 12
Po Rares (Chagaeanccoeeer | :
Watterson, H.R........ J
* Above low-water in the Ohio river at Cincinnati.
PENNSYLVANIA.
Boyers, W. R........0e0.| Blairsville......] Indiana... vee. 40 31 74043) 9) VOLO mum: 12
Brugger, Samuel .........-.| Fleming......./ Centre ........ 40 55 77 53 78000) SRR. sess 12
Darlington, Fenelon... ...| Parkersville ...| Chester........ 39 54 75 37 ZLSis | ees RU rorwre 12
Friel, P .....cee.eeeeeeeeee.| Shamokin .....| Northumberl’d. 40 45 76 30 OU an Dah rece 12
Hance, Ebenezer..........| Morrisville..... Bucks. «|, 40 12 74 48 39 | B.T.R 12
Heisely, Dr. John... Harrisburg. ....| Daup! info scsen 40 16 TG UO |\letereter ter 12
Heyser, W oy Chambersburg..| Franklin. .e..e 39 58 77 45 618 !
Hickok, W.O... Harrisburg.....| Dauphin. ..... 40 20 76 59 320 12
lioffer, Dr. Jacob Re Mount Joy.....| Lancaster..... 40 08 1G" 30 Baletatacs ae 12
net Oe By ss E a ' Nazareth......| Northampton..| 40 43 75 21 530 8
Tone Rev M.-+u-r++++ |! Gettysburg.....| Adamsieesee0s.| 3949 | 7715 | 624 | B.T.R..| 12
Kirkpatrick, Prof. Jas. A...| Philadelpbia...| Philadelphia... 39 57 75 10 pov Brminiceeles)|| tke:
Kohler, Edward ..........: N. Whitehall ..| Lehigh ...... 40 40 15 26 25) eaaielateieee | LO
Lyceum, Jefferson College .} Cannonsburg ..| Washington.... 40 17 80 10 SEG WAR a ciaiaece 5
McNett, E.L..........+.+.-| Carpenter... .| Lycoming...... Al 37 NGPOBE |ecsisnet |, Laie: <\siaie 5
Martindale, Isaac C.......| Byberry .......| Philadelphia... 40 05 75 00 10) PE Rexreaarell eee
ce Germantown ,.| Philadelphia s..|.sseveesve[essevesees[seeseeee| Brosseves] 8

°

METEOROLOGICAL OBSERVERS.

PENNSYLVANIA—Continued.

3 © 2
= zg 3 25
S & s |e:
Name of observer. Station. County. Ss 5 ee g 5
< teal a 3 So
= aw = Ss 2
© 2 2 2 om

Z e = 5 A

Sits et Feet.
Muller, Prof. Rudolph.....| Latrobe ....-..] Westmoreland. 40 97 79 32 $&5 | B.T.R 9
Ralston, Rev. J. Grier......| Norristown....}/ Montgomery... 40 08 75 19 NS Sr A WAuaetscate 12
Scott, Samuel..............| Worthington...| Armstrong... . 41 50 7Y 31 T0507 eae. 12
Swift, Dr Paul ..........-| W Haverford..| Delaware...... 40 00 75 21 400 |T.R. 10
Taylor, Jolin... ...e0.ee.-}| Connellsvilie...| Fayette........| 40.00 MOESO MT fiarsreyee eel ely esterase 4
Tracy GeorgesEscictsicle soe SNE Alieghany...... 40 33 80 14 656 | B. T.R.. i
RHODE ISLAND.

Caswell, Prof. Alexis......| Providence... | Providence.... 4\ 49 71 25 120 | iNaapooose|| 4
Sheldon, H. ©..........-..} Providence....| Providence .... 41 50 de 25 dacan Be TaRe.| 72)
TENNESSEE.

Stewart, Prof. Wm. M.... | Crackle. Montgomery... 35 28 | 87 13 | 481 | Avvscces | 12

UTAH.
Pearce, Harrison.......6. St. George... Washington... 37 00 | 114 00 bes ve a rwatsiate | 6
VERMONT.
Buckland, David ....-.....} Brandon .... { Rutland ....... 43 45 OnOOMM ee caveleins Aya 12
Chickering, Rev J. W.....| Sprineficld.....| Windsor......-] 43 18 72 33 SOD) Miele coal tamil
Cutting, Hiram A......... | Lunenburg ....] Es.ex ...... 44 28 71 4l D4 RAS. sices 12
MCad SiO seiceicatslaicisvsjicrorye |) EMULIAN Gs werteiacers Rutland).cn cee || cir selma |ealeole Geasstcie 12
Paddock, James A.........| Craftsbury .....| Orleans........ 44 40 72 29 DOO) Rl Uaretere 12
Parker, Joseph.-. ........| West Rupert...) Bennington.... 43 15 73 11 WOO wlvesseres 12
Petty, MCKy ec. epics sancee) BUCINGtON +6... | Chittenden .. 44 27 73 10 SE WAlsaleteterete iL
Tobey, James K....20 ooo. Wa-hington... 44 22 LOOM |(ehrestsisc TOR 5

Walaishsaceier |

WASHINGTON TERRITORY.

Swan, James G..... vceee- #0] | a

Neeah Pay... sieves 28 41 | 124 37

WISCONSIN.

Atwood, Isaac ..s0eese...| Lake Mills.....| Jefferson ..... 43 00 SOTOOM ces ete ee, ||) Neewremietets 1
Bell, James H.........-. .| Kilbourn City..] Columbia....../ 43 30 90 00 Oa UNnasenisisint! mee
Curtis, W. W....-.0% ese. Rocky Run.....| Columbia...... 43 26 SOOO Ae mace "Tray Hectares |e,
Filis, Edwin, M D .......| Ashland.......} Ashland. ..... 45 33 91 00 GION Reema) ele
Gridley, Rev. John ........| Kenosha...... | Kenosha ...... 42 35 87 50 600 | B. T.R..] .12
Kelley, Charles W.........| Delafield......| Waukesha .... 43 06 &8 3 S000) Bidet 9
Kelsey, Prof Henry S..... Beloit. 34s ccey|) ROCK ss .eme sietale 42 30 89 04 OO) Rade ese ake
Lapham, Increase A.......| Milwaukee ... | Milwvukee .... 43 03 7 56 093) | AN eeeces| 12
Lups, Jacob..... eeceeesees| Manitowoc... | Manitowoc....| 44 07 7 45 638) |SBUs.. 12
Mann. William ...........| Superior ..... | Douglas....... 46 46 92 03 GOU ie iesretse| lec
Mathews, George..........| Brighton...... | Kenosha ......} 42 36 88 03 UO TDNIsercte erate 6
Powers, M. carr as Dartiord...... | Green Lake... 43 39 BOD 5 Mee ate BoE ee 4
Sterling. Prof. John W... oe x

eae Willan Madison...... | Dane....... «.| 43 05 9:25. |, 1,068 } Ase covdace 7
Strunk, Daniell... ..cuvees) Janesville. ... |) Rock#scjcccc.|) 42 43 89 39 WSO) eb ccreae soi ete
Winkler, Carl, M. D.......} Milwaukee ....] Milwaukee. ...| 43 03 8&7 57 600 | B T.R..} 12
Woods, William ..........] Weyauwega...] Waupaca......] 44 15 88 50 S507) Ws <ctaien 12

o>
©

METEOROLOGICAL OBSERVERS.

MEXICO.
a »
a =.
3 E es
Name of observer, Station, = 5 : Ee = 2
5 rm = 5 -o
5 ee ‘E0 5 .2
3 3 3 = ore
| A = = Zz
rae ne Feet
laszlo, Charles.... ......| San Juan Bautista, Tabasco .... 17 47 $2 36 AQT EAs crarelerets g
INIETOS SVAN <eieaia isles meine sie [RCOLGOVAS VELa OLUZ acca! cele vie sie USSGe Ne som odoord| soos nobc {SAL ye 12
Sartorius, Dr. Charles..... Mirador, Vera Cruz.....cceeeee 19 15 96 25 3,600 | Avccsenss 12
CENTRAL AMERICA.
RIONLES (GaN: cee carcicee .-| San José, Costa Ricas.......0.. Y 54 &4 06 ae) le ndvet Re ckieis 1g
Canudas, Antonio...... 0... Guatemala College, Guatemala. . 14 37 90 30 4,856 | A.......- 12
White, William ‘I’., M. De IASDRW alll eicimateselaieseyelcicieree's eres 9 2] UD dace Haare stoves | [tees elsielola v
BERMUDA.
Royal Engineers, (in the | Centre Signal Station, Saint }.......cc.|..ccsecces|socecee-| Ascoccse-| 12
Royal Gazette.) George’s.
SOUTH AMERICA.
Herning Ce iene sine ee--| Government Plantation, Rus- |.......... ialvieteleraterei|/aleie'sivie'es pial 1%

{ tenberg. colony of Surinam,
} Duteh Guiana.
|

DEatus OF OBSERVERS.

Lucian Fish, Burlingame, Kansas, early in 1861.
Andrew G. Carothers, at Martinique, West Indies, October 20, 1862.
Andrew J. Babcock, of Aurora, Lilinois, at Pittsburg Landing, Tennessee.

Colleges und other institutions from which meteorological registers were received
during the year 1862, included in the preceding List.

Novascotias- 52-5 2s Acadia College|.224s22sesee- secs oe Wolfville.
Kinesis Collesees sas sees est ene as Windsor.
Wanadareoso-=s2-ccc5 = .| Granimar schoole ss. cesss2see-2—. = Niagara.
Magnetic Observatory........-.---- Toronto.
Connecticut, 2-2. -ceee- Wesleyan University -...-_.. ------| Middletown.
filinois!zs225— Seo ss eae Lombard! University..-.-...---=-=- Galesburg.
McKendree College.......--.-..... Lebanon.
Uitiversity of Chicagoss2=s2-2-sceee Chicago.
JOWSa\ece cece. scesee COrmelli@olleres sas se cacccn a a S2kE Mount Vernon,
GriswoldiCollese=2 2. sae soe oo soe Davenport.
Iowa State University....- sco Towa City.
Wellow Spring Colleges 222 2 ea Kossuth.
Meine soa: = pene males sa Oaks Grove Seminaty ssa se oes enone Vassalboro’.
Maryland 2-6522- voce Paemicultural Colleze 222s -=e esse se= Prince George’s county.
Washington College.....-........ -| Chestertown.
Massachusetts ........-.| Amherst College._.-.- Se eat thy bt Amherst.

State Lunatic Hospital........-...-] Worcester.
Williams’ College ........--.--....| Williamstown.

70. METEOROLOGICAL CONTRIBUTIONS.

ea
Colleges, §c., from which meteorological registers were received, &c-—Continued.

Michigan .-.c.. --.< wajoee|) Marine Hospital: sssjcsncceeaecees Detroit.
MISSOUTI ge sob seine esa Sty Louis University: ---<.cc-s—=—=5- St. Louis.
INGWHICISEY, «sesemi= sees Hreehold Institute ss.) c-— so aienee Freehold.
INGw) YORK sce. see mamas Institution for Deaf and Dumb.--..-- New York.
Sts John’s Colleges. 2-22 .ccca- --..| Fordham.
University of) Rochester------2-5-+=- Rochester.
Young Men’s Association -.....---- Buffalo.
Ohios is. See eesecoe ee = Farmers’ Coltege.. 22-.itencaseeee'ae) College Hill.
Halcyon Academy, cscsscmeceen se Croton.
Otterbein University ....-=-...-.-. Westerville.
Urbana University....----- Seseioet Urbana.
Western Reserve College..--..----- Hudson.
Woodward High School........-.-- Cincinnati.
Pennsylvania, ---.-..--- Central High School .-.----------- Philadelphia.
Haverford College See eae ea ieres West Haverford.
se College oo ssNjcin cn cece pee Cannonsburg.
Vincentisi@olleges--- -aiemamieaee Latrobe.
ean Academy, ..-------- Sewickleyville.
Rhodewislandss2ssu.— 1 Brown Universityesess -<nssecsscee Providence.
Tennessee feenecirsoeces Stewart) Collepeteas mae oo aacinceee Clarksville.
Vermont, 222s soe-eaccoe University of Vermont...........-. Burlington.
Wisconsin =ooo2 = sano = Beloit:College- c= ost. ccm ee eale Beloit.
Wisconsin, University coc tessccecss Madison.
Central America......-- Guatemala) Collecestem scene ocstae == Guatemala.

LIST OF METEOROLOGICAL MATERIAL CONTRIBUTED IN ADDITION 110 THE REGULAR
OBSERVATIONS.

Asiatic Society of Bengal—Journal of the Society, 1860, containing abstracts
of hourly meteorological observations, taken at the surveyor general’s oflice
at Calcutta, for June to November, 1859, inclusive.

Journal No. 1, 1861, containing same for May, June, and July, 1860.

Bowen, Miss Anna M. J—Summary of observations of thermometer, winds,
and clouds, for the hours 7 a. m. and 2 and 9 p. m., and for each month
and season during the year 1862, at Elkhorn city, Nebraska.

Boettner, Gustav A. —Drawings of snow crystals observed in the winter of
1862-63, at Chicago, Tee!

Brackett, George Emerson ——Monthly abstract of observations in 1862, at Bel-
fast, Maine, printed in the “ Republican Journal;” summary for the year
printed in the “Maine Farmer,” Augusta.

Brown, Rev. John J—Summary for 1861 at Dansville, N. Y., giving mean, ex-
tremes, and range of barometer and thermometer for the year, and amount
of rain and number of days without frost. ,

Buchner, Dr. Otto—Der Meteorit von Shalka in Bancoorah und der Pidding-
tonit. Von dem W. Haidinger. (Sonder Abdruck aus dem XLI. bde. d.
Sitzungsb. d. Kais. Akademie d. Wissenschaften.) 8vo. p. 8.

Einige neuere Nachrichten iiber Meteoriten, namentlich die von Bokkeveld,
New Concord, Trenzano, dis Meteoreisen von Nebraska, von Brazos, von
Oregon. Von W. Haidinger. 8vo. p. 6.

Die Caleutta-Meteoriten, von Shalka, Futtehpore, Pegu, Assam und Segowlee
im k. k. Hof-Mineralien-Cabinete. Von W. Haidinger. S8vo. p. 14.

Die Meteoritenfille von Quenggouk bei Bassein in Pegu und Dhurmsala im
Punjab. 8vo. p. 7.

Meteoreisen von Rogue River mountain in Oregon und von Tuoson, Sonora,
gesandt von Herrn Dr. Charles T. Jackson. 8vo. p. 2.

Die Dandenong-Meteoreisenmasse in Melbourne. 8vo. p. 1.

METEOROLOGICAL CONTRIBUTIONS. _ ta

Der Meteorit von Parnallee bei Madura im k. k. Hof-Mineralien-Cabinet.
Svo. p. 4.
Der Meteorit von Yatoor bei Nellore in Hindostan. 8vo. p. 2.

[The preceding eight articles are by W. Haidinger, and are separate
pamphlets extracted from “ Seitzungsb. d. Kais. Akademie d. Wis-
senschaften.”’|

Carothers, Andrew G., U. S. consul, Martinique—Printed copy of the daily
meteorological observations made at the military hospitals, Guadaloupe,
from October, 1861, to May, 1862, inclusive.

Extract from the Physical History of the Antilles, by M. Moreau de Gonnis,
giving the dates of a number of hurricanes since 1825.

Caswell, Professor Alexis, D. D—Monthiy summaries of observations made at
Providence, Rhode Island, during the year 1862. (Published in the “ Provi-
dence Daily Journal.’’) °

Connolly, Henry —Observations at Rigolet, Esquimaux bay, Labrador, from
July, 1860, to June. 1862, inclusive.

Dana,, Wm. B.—Meteorological tables, being a summary for the year 1859, by
Henry Willis, at Portland, Maine. (Printed.)

Dudley, Timothy—Summary of observations for the year 1862 at Waverley,
I}linois, giving the mean and extremes of thermometer and amount of rain
for each month and for the year; also, date of earliest and latest frost.

Foster, W., jr—Notices of meteors and aurora in July and August, 1862.
(Providence, R. I., Journal, August 23, 1862.)

Frantzius, Dr. A—Thermometer and barometer observations at San José, in
Costa Rica, Central America, at 7 and 10 a.m. and 4 and 7 p. m., daily,
from September. 1861, to August, 1862, inclusive.

Frey, S. C-—Newspaper record of thermometer and barometer at Springfield,
Ohio, from February 4, 1861, to May 11, 1862. °

Gardimer, R. H—Printed summary of his observations at Gardiner, Maine, for
the winter of 1861-62, and a comparison with the mean and extremes of
the preceding twenty-six winters.

Hague, Captain, astronomer of the North American Boundary Commission on
the part of the English Commission—Monthly means and extremes of
observations with barometer, thermometer, and psychrometer; also, the
number of rainy days and amount of rain, from August, 1860, to Decem-
ber, 1861, at Fort Colville: Washington Territory; latitude 48° 39’ 58” N.,
longitude 118° 3! 52.8" W.; height above the sea, 1,268 feet.

Hays, W. W., M. D—Summary of the observations on temperature and rain
made at the presidio of San Francisco, California, by the surgeons of the
United States army at the post from July, 1852, to December, 1862.

Amount of rain measured at Benicia barracks, California, during each month
from March, 1856, to February, 1863; also, a separate table showing the
amount in the “rainy season” of each year during the same period.

Herschel, Sir J. F. W—Manual of meteorology, by Sir J. F. W. Herschel,
Bart. Extracted from the Admiralty Manual of Scientific Inquiry, third
edition, 1859. 16mo. pp. 52. ®

Letter from Sir J. F. W. Herschel, Bart., to Sir J. W. Lubrock, Bart., on
shooting stars. London, 1861, 8vo., pp. 4.

Report of the meteorological committee, part 1. Read July 17,1837. Printed
at the Gazette office, Cape Town, Cape of Good Hope. 8vo., pp. 20.
Hyde, Gustavus A—Summary of observations at Cleveland, Ohio, for the year

1862, and comparison with the preceding six years.

Ives, Willkiam.—Article on the climatology of Buffalo, New York, prepared by
him for H. Thomas’s Buffalo City Directory; five pages.

Lake Winnepissiogee Cotton and Woollen Manufacturing Company, New
Hampshire—Amount of rain for each month, in 1862 at the outlet of Lake

72 METEOROLOGICAL CONTRIBUTIONS.

Winnepissiogee, in the town of Laconia, New Hampshire, and also at Lake
Village, about four miles south on the same stream of water. ‘Transmitted
by J. B. French.

Lapham, I. A—VDates at which the ice left Milwaukee river in each year from
1837 to 1863, inclusive.

Table showing the date of the arrival at Milwaukee, Wisconsin, of the first
vessel in each year from the “lower lakes” from 1837 to 1863.

Lewis, James, M. D.—Uourly observations of temperature at Mohawk, New
York, registered by his metallic self-recording thermometer during the year
1862, with the means calculated for each half month.

Logan, Thomas M., M. D.—Wydrography, meteorology, and hyetography of
Sacramento, California, for a series of years, embracing chart of the oscil-
lations of the Sacramento river from 1853 to 1862, inclusive; monthly and
annual means of barometer, thermometer, and psychrometer, with force and
direction of wind for the same period; monthly and annual amount of rain
from 1849 to 1862, inclusive, together with general remarks on the weather
and seasons.

Macgregor, Charles John, M. A—Head master of the Grammar School, Strat-
tord. Abstract of observations for the years 1861 and 1862, taken at
Stratford, Canada West; 8vo., 6 pps.

MeLam, Wm. D.—Observations on temperature and state of the weather at
Central City, Gilpm county, Colorado Territory, from December, 1860, to
May, 1861.

Martmndale, Isaac C—Summary of meteorological observations at Byberry,
Philadelphia county, Pennsylvania, for the year 1862.

Notes of the wearher at Byberry, Pennsylvania, at various times from the
year 1798 to 147, collected by I. C. Martindale from authentic accounts.

Mullan, Lieut. John, U. S. A-—Meteorological record kept by 'Theodore
ioleski, at Cantonmeut Wright, Rocky mountains, on the military road
expedition under command of Lieutenant John Mullan, United States army,
during the winter of 1861-62.

Navy Department, Bureau of Medi-ine and Surgery—Monthly meteorologi-
cal registers k-pt at naval hospital, Chelsea, Massachusetts, year 1862,
excerpt April and May; naval hospital, New York, year 1862; naval hos-
pital, Philadelphia, year 1862.

Newton, H. A—An account of two meteoric fireballs observed in the United
States August 2 and August 6, 1860, with computation of their paths, by
H. A. Newton, of Yale College. (Irom American Journal of Science and
Art.) 8vo., 12 pp.

Nitvhy, F. A—Account of a severe hail storm at Herman, Gasconade county,
Missouri, June 17, 1862.

Observatoire Impérial, Paris—Annales, tome XX, containing meteorological
observations for 1859, at Paris.

Daily meteorological observations received at the observatory from various
parts of Europe by telegraph, and lithographed for distribution.

Observatorio Pugico-Metvorico de la Habana, Don Andres Poey, director—
Hourly meteorological observations with full sets of in-truments from July
to December, 1862, inclusive.

Paine, Dr. H. M—Monthly summaries of observations at Clinton, Oneida
county, New York; printed slips.

Payot, Venance-—Obsvrvations météorologiques faites a Chamounix, pendant
Vannée 1858, Janvier et Février 1859, faisant suite a celles publiées en
1857, par M. Venance Payot, naturaliste. (Extrait des annales de la
Societé d’Agriculture, d’histoire naturelle et des arts utiles de Lyon, dans
sa séance du 14 Mars, 1862.) 8vo., 20 pp.

METEOROLOGICAL CONTRIBUTIONS. 73

Pollard, T. F—Observations at Brookfield, Vermont, of temperature, winds,
clouds, and weather, from June 24, 1859, to the end of the year 1862.
Radcliffe Trustees —Astronomical and meteorological observations made at the
Radcliffe Observatory, Oxford, in the year 1858, under the superintendence
of Manuel J. Johnson, M. A., late Radeliffe observer, reduced and printed
under the superintendence oF the Rev. Robert Main, M. A., Radcliffe ob-
server. Vol. XIX; published by order of the Radcliffe trustees, Oxford,

1861.

Rankin, Colin.—Register of barometer and thermometer from Moose Factory
to Lake Superior, June 17 to July 2, 1862.

Riblet, J. A—Summary for the year 1862 at Orchard Farm, near Pekin, Tli-
nois, giving the mean and extremes of thermometer and amount of rain for
each month and for the year, and the date of the earliest and latest frost.

Royal Geographical Society, London.—Proceedings of the society, vol. 6, No.
2,°1862, containing a notice of the earthquake of Erzerum, in latitude
ae SomeOW longitude 41° 18" 31", June, 1859, by Robert A. O. Dalyell,

palickus rs ae her Britannic Majesty’s consul at Hrzerum.

Sheldon Jah C.—Monthly summaries of observations made at Providence, Rhode
Island, in 1862. (Published in the «‘ Evening Press.”

Societa di Acclimazione e di Agricultura in ee —Proceedings containing
monthly registers of observations at Palermo.

Soctite des Sciences Naturelies de Neuchdtel—Bulletin 1859 to 1861, volume
5, containing :

Precipitation de la rosée pendant le jour, par M. Favre. pps. 1-4.

Rapport du comité métcéorologique pour l’année 1858 :—Resumé des phéno-
ménes les plus remarquables qui se sont passés & Neuchatel dans le 16me
siecle—Résumé météorologique pour l’annce 1858; le résumé comprend
les stations de Neuchatel, de Chaumont, de Fontaines, et de la Chaux-de-
Fonds, les observations limnimctriques des trois lacs de Neuchatel, de
Bienne et de Morat. pps. 102-147.

Résumé des observations mctéorologiques relatives aux vents, faites a Cor-
neaux de 1812 4 1819, par M. le pasteur Peters; calculé et presenté, par.
M. le professeur IL. Ladame. pps. 148-154.

Rapport du comité météorologique pour l’année 1859:—Résumé de phé-
nomenes les plus remarquables & Neuthatel dans le 17me si¢cle.-—Résumeé
des observations faites en 1859 dans le canton et les observations limni-
métriques des trois lacs. pps. 266-321.

Résumé des travaux de M. Schonbein sur ozone, présenté par M. Kopp,
professe ar. pps. 322-345.

Blot sur quelques instruments mc¢téorologiques enregistreurs, par M. Hipp.

s. 587-590.

Ra rpport du comité métcorologique pour l’année 1860 :—Résumé des a
noménes les plus remarquables & Neuchatel de l’an 1700 4 Van 175
Résumé météorologique pour l’année, 1860. pps. 675-752.

Note sur la température du lac a différentes profondcurs, par H. Ladame,
professeur. pps. 753-761.

Note sur la température de l’cau des fontaines de la ville de Neuchatel, par
Ti. Ladame, professcur. pps. 762-763.

Société Metcorologique de France-—Annuaire, 1861.

Swan, Caleb—Amount of rain at the Eastern Dispensary, Grand&street, New
York, during each month of the year 1862, from the record kept by Dr. J.
P. Loines, house physician of the dispensary; also, during each year trom
1854 to 1861, inclusive.

Taylor, John —A table showing the cold days in each year from 1843 to 1861,
inclusive, at Connellsville, Pe nnsylvania; also, the mean temperature and
amount of snow for each month in the year 1861.

v4 | METEOROLOGICAL CONTRIBUTIONS.

Thatcher, A. H—Three small manuscript books containing barometer and
thermometer observations and notes on the weather, kept at New York
from August, 1855, to June, 1862.

Tolman, James W.—Monthly and annual summary of observations for 1862,
made at Winnebago, Illinois. (Published i in the “Rockford Register.’’)
Trembley, J. B., M. D—Monthly summaries of observations during the year
1862 at Poteda: Ohio, with remarks on the weather and comparisons with

previous observations. (Published in newspaper.)

White, W. T., M. D.—Surgeon-in-chief of the Panama railroad. Fall of rain
at Aspinwall, New Granada, from 1857 to 1862.

Whitehead, W. A—Monthly and annual summaries of observations made at
Newark, New Jersey, during the year 1862, with comparisons of the same
with the means and extremes of a series of years. (Published in the “Sen-
tinel of Freedom and Weekly Advertiser.’’)

Woodhouse, Mrs. E. A—Observations of Professor Parker Cleveland, (her
father,) from 1808 to 1859, at Bowdoin College, Brunswick, Maine.

REPORT OF THE EXECUTIVE COMMITTEE.

The Executive Committee respectfully submit to the Board of Regents the

following report of the receipts and expenditures of the Smithsonian Institution

‘during the year 1862, with general estimates for the year 1863:

General Statement.
RECEIPTS.

The whole amount of Smithsonian bequest deposited in the
treasury of the United States is $515,169, from which an an-
nual-income-at, six per cent. is derived of-..--.-....------

The extra fund of unexpended income is invested as follows, viz:

In 75,000 Indiana 5 per cent. bonds, yielding..........-.--

In 53,500 Virginia 6 per cent. bonds, yielding nothing in
1862.

In 12,000 Tennessee 6 per cent. bonds, yielding nothing
1862.

In 500 Georgia 6 per cent. bonds, yielding nothing in 1862.

In 100 Washington city 6 per cent. bonds, yielding during 1862.

Premium on sale of $1,875 gold, (interest) paid on Indiana
ponte sere Uli Us nA ee ene cccioteicinta(n niece eae < welnchm jeim ers

in
q

ARotaleincomecteocrecss oti cie.c & abs oo etenciereie
Balance in the hands of the treasurer, January, 1862....----

EXPENDITURES.

Hor ioildime furniture, and fixtures...) Ss.)2c.02ctol2.00---
Poneeemenalpexences<-.eya tetera gece te iy ints emia eer area] = aot
For publications, researches, and lectures-.-....--...-----+
For library, museum, and gallery of art............------:-

Total expenditure... <i 5c6<..0s sheen

Statement in detail of the expenditures of 1862.

BUILDING, FURNITURE, AND FIXTURES.

Building incidentals. ......------+----22+ ee 2- $1,672 34
Furniture and fixtures in general.......--------- 80 02
Furniture and fixtures for museum....-..-.--... 485 30

$30,910 14

3,750 00

6 60

759 37

39, 425 51
22,045 17
07,470 68
Zi Ooms Oe

$29, 509 61

$27,961 07

$2,237 66

76 REPORT OF COMMITTEE.

GENERAL EXPENSES.

a
Meectines of the’ Boatd os o)se 1.0 octet aoe $81 00
Tiehtine and. heating gape o cpeye ere. c,- Be Ch eemee 1, 142) 26
Postage ~iscin¢ doen eee eee Pee teen BOS OO
Mransportation, Semen lar al ate cians 1 eee 733 10
Foxchan ges © ic cst ate wa ete wid 220 2 aparece mle aes 7,000) 32
GALLON ERY oo = eure iss fais, <i are eine he ee 281 38
Generali printing ash nue sis. eet Ch oie oan eteeae 441 46
APPAR ADU y sc canta ats mus te sbi yche oct tts Spates Foe yoked tae 119 06
Bey aro AOI cA eae ee Siete Na eee 408 45
Imeidentals, eeneval’. ©. 2.5 ans stncee eee eee eee SoS
xtra clerkshire =. se. 7.6 one aa eee eee 405 00
Dalaries; SCCLCLATY. =)... <-sis 27s wie sia wie | egsraray eters = =pciells 3,500 00
Ohief clerk, bookkeeper, messenger, &e ..-....... 2,344 00

— 11,674 41

PUBLICATIONS, RESEARCHES, AND LECTURES.

Smithsonian Contributioneias. Ws Meee: 2c oe ee $932 97
Smithsonian Reporte ...1a:.--2e ere ae oes. ee 219 88
Smithsonian Miscellaneous Collections...........- 33-774 25
Meteorol opyg: aren te a eee ere ieee letter teeta 1,963 08
Researches and investigations. ........-...2-.-.41 94 75
Te Ctures 2. \letas miss tren eet eae eee eee 759 51

—————_ 7, 744 44

LIBRARY, MUSEUM, AND GALLERY OF ART.

Goat of -books-and binding 222%... 36.s25 5 - Soe oe Piola os
Payoot assistants anv libranycl ses. co ere se 1,215 00
ihransportation for library. 2022 21 ica eile Renae 346 76
Incidentals for Wbrar yo 2:6 ccs: arena sein ores = aie 44 25
Museum, salary of assistant secretary....-......- - 2,000 00
Leta pomiablon chor, MOS OMe see) tere are sete ye terete ere 3 354 54
Jnecidentals for museum. <2. semen eee eters erste 146 459
Noh gil C Se See arece oma to oc cota no tae 555 29
Gallery Oneattrss (2.001 ig overs metepetere a) cewaeye eect 128 50

———___ 6, 304 56

Total expenditures «222.25 cree eens eee ee eee $27, 961 07

It will he seen that the whole income during the year 1862 was $35,425 51,
instead of the estimated income, $34,666 14. This difference is due to the
receipt of $759 37 as premium on the gold in which the first half year’s interest
on the Indiana bonds was paid.

The expenditures during 1862 were $27,961 07, leaving $7,464 44 to be
added to the balance in the hands of the treasurer on the 9th of January, 1862.

The amount of bills for work already contracted for will not exceed $2,500.

The foregoing statement is an actual exhibit of the Smithsonian funds, irre-
spective of credits and payments which have been made in behalf of other
parties. Jor example, the Institution during the past year has paid several
bills for work done on account of the government, the amount of which has
been refunded and credited to the appropriations from which the expenditure
was originally made.

REPORT OF COMMITTEE. CF

The appropriation from Congress for the preservation of the collections of the
exploring and surveying expeditions of the United States has been expended,
as heretofore, under the direction of the Secretary of the Interior, in assisting
to pay the expenses of extra assistants in the museum, and the cost of arrang-
ing and preserving the specimens. ‘The‘sum received from this source has been
credited to the museum, and has served to diminish the amount of expenditures
for that object on the part of the Institution, although it has not been sufficient
to defray all the expenses on account of the preservation and public exhibition
of the specimens.

The articles intrusted to the care of the Institution are in good condition,
and the work of the distribution of the duplicates of the government as well as
those of the Institution is still in progress.

A part of the expenditure on the building is due to refitting the apparatus
room, and re-covering, with tin, the northesn portion of the roof of the west con-
necting range which was blown off during the storm of February 24.

From the foregoing statements it will appear that the financial affairs of the
Institution are still in a prosperous condition, and that the Board of Regents
could resign their trust to-day, with the undiminished original bequest of
Smithson in the treasury of the United States, with over one hundred thousand
dollars on hand or in secure investments, and with $66,000 in southern State
stocks, from which it is hoped at some future time interest may be received.

The committee submit the following approximate estimates for the year 1863

Estimated income........ Bae ects a! eer 2 nit Rea ores Lane . $34,666 1:

ESTIMATED EXPENDITURE.

For building; furniture, and fixtures....---..--. PAS acct $2,000
Pore memeta he menses sees laters tate eieyetela aie cl Sete rele alate resin 10,500
For publications, researches, and lectures.......-- er as eae 10,500
For library, museum, and gallery of art..... shies) eiata.cesle tye ave 9,000

32,000

The *committee have carefully examined the books and accounts of the
Institution for the past year, and find them to be correct.
Respectfully submitted. : .
JOSaG: TOLTLEN.
: A. D. BACHE.
Fesrvuary, 1863.

JOURNAL OF PROCEEDINGS

OF

PHE BOARD OF REGENTS

or *

THE SMITHSONIAN INSTITUTION.

WASHINGTON, January 21, 1868.

Tn accordance with a resolution of the Board of Regents of the Smithsonian
Institution, fixing the time of the beginning of their annual session on the third
Wednesday of January of each year, the Board met this day in the Regents’
room.

Present: Hon. H. Hamlin, Vice-President of the United States, Hon. W.
P. Fessenden, Hon. 8. Colfax, Hon. 8. 8. Cox, Hon. E. McPherson, and the
Seerctary.

Several members being absent on account of a severe storm, the Regents
devoted the meeting to the examination of the building, museum, library, and
collections...

The Board then adjourned, to meet on Saturday, January 31, 1863.

Wasuineton, D. C., January 31, 1863.

An adjourned mecting of the Board of Regents was held this day, at 11
o’clock a.m. Present: Vice-President Hamlin, Hon. L. Trumbull, Hon. G.
Davis, Hon. 8. S. Cox, Professor A. D. Bache, the treasurer, Mr. Seaton, and
the Secretary.

The Vice-President was called to the chair,

The Sceretary announced the death of Hon. James A. Pearce since the last
session of the Board, and stated that Hon. Garrett Davis, who was present, had
been appointed a Regent by the President of the Senate to fill the vacancy.

Professor Bache, after a series of appropriate remarks, offered the following
resolutions, which were unanimously adopted :

Resolved, That the Board of Regents of the Smithsonian Institution deeply
mourn the loss of their distinguished fellow-regent, James Alfred Pearce.

Resolved, That in the death of Mr. Pearce our country has lost a refined and

induential citizen, the Senate of the United States an able, judicious, honest
statesman, and this Institution an active, intelligent, and learned regent.

PROCEEDINGS OF THE REGENTS. © 79

Resolved, That we sincerely condole with the afflicted family of Mr. Pearce,
and offer to them our heartfelt sympathy in their great bereavement.

Resolved, That a copy of these resolutions be communicated by the secretary
of the Smithsonian Institution to the family of the deceased.

On motion of Mr. Trumbull, it was

Resolved, That Professor Bache be requested to furnish a copy of his remarks
in relation to Hon. J. A. Pearce for insertion in the journal of the Board of
Regents.

The Secretary announced the death of William McPeak, who had been the
janitor of the Institution from its organization, and recommended the payment
by the Board of his funeral expenses.

On motion, the Secretary was authorized to pay the bill of funeral expenses
ef the late janitor of the Institution,

Professor Bache, in behalf of the executive committee, presented a general
statement of the financial condition of the Institution, and an account of the
expenditures during the year 1862.

The Vice-President suggested the propriety of taking some action respecting
Mr. George E. Badger, whose name still appeared as a member of this Board,
but who was known to be in rebellion against the government.

After some remarks relative to the knowledge of the fact of Mr. Badger’s
present position, by several members of the Board, on motion of Mr. Trumbull
the following resolution was adopted :

Resolved, 'That the secretary be directed to inform the Congress of the United
States that George E. Badger, one of the Regents of this Institution, has not
attended the recent meetings of the Board, and they are advised that he is now
in rebellion against the government of the United States, and submit whethe-
the name of said Badger should longer remain on the list of Regents of said
Institution.

On motion, the Board adjourned to meet on Tuesday, February 3, at 7
o’clock p. m. .

WASHINGTON, February 3, 1863.

The Board of Regents met this day, pursuant to adjournment, at 74 o’clock
p- m., in the Regents’ room. Present: Hon. L. Trumbull, Hon. G. Davis, Hon.
IE. McPherson, Hon. 8. S. Cox, Hon. R. Wallach, General J. G. Totten, Pro-
fessor A. D. Bache, and the Secretary.

Mr. Trumbull was called to the chair.

The minutes of the preceding meeting were read and approved.

The Secretary presented his annual report of the operations of the Institution
during the year 1862, which was read and approved.

Professor Bache presented the report of the executive committee, containing
an account of the receipts and expenditures for the year 1862 and estimates for
1863, which was read and approved.

On motion of Professor Bache, it was

Resolved, That the chairman appoint a member of the Board to fill the
vacancy in the executive committee occasioned by the death of Mr. Pearce.

The chairman appointed Hon. Richard Wallach to fill the vacancy.

80 " PROCEEDINGS OF THE REGENTS.

The Secretary presented to the Board the following communications :

War DEPARTMENT,
Washington City, January 26, 1863.

Sir: I have this day requested Hiram Barney, esq., collector of the port of
New York, to send to you the books, maps, papers, and other articles, now in
his possession, taken by the United States forces in South Carolina, to be held
in the Smithsonian Institution, subject to the orders of this department. I
would be pleased to confer with you in regard to this matter if you will be so
good as to call at this department Tuesday, at three o’clock p. m.

I am, sir, very respecttully, your obedient servant,
EDWIN M. STANTON,
Secretary of War.
Professor Josepu HENRY,
Sceretary of the Smithsonian Institution.

War DEPARTMENT,
Washington City, January 29, 1863.

Str: The Secretary of War directs that you take possession of the books and
papers of Bishop John Johns, at his late residence at Fairfax Seminary, and
transmit them under sufficient guard to Professor Henry, at the Smithsonian
Institution, in this city.

Very respectfully, sir, your obedient servant,
EDWARD CANBY,

Brigadier Gcneral United States Volunteers.

Brigadier General J. P. SLouau,
United States Volunteers, Military Governor of Alexandria.

Professor Henry stated that in his interview with the Secretary of War the
latter had requested that an inventory of the books, &c., should be made, and
that they should be carefully preserved in a room by themselves. The Secre-
tary, on behalf of the Regents, provisionally agreed to these propositions on
condition that the expense of the shelving and fitting up of the room, and the
preparation of the list, should be at the expense of the government.

The Board of Regents acquiesced in the propriety of taking charge of these
libraries, and of carefully preserving them until the termination of \the present
war.

The Secretary stated that the libraries had been received—the one from
South Carolina, in thirty-three boxes and one bundle, by the transportation
company from New York, and that of Bishop Johns, in loose volumes, by army
wagons from Alexandria. It is proposed to place these libraries in the unoc-
cupied apartment in the south tower above the Regents’ room.

The following extracts from the correspondence of the Institution were then
presented, after which the Board adjourned, to meet again, if necessary, at the
call of the Secretary.

WESTERN UNION TELEGRAPH ComPANy,
_ Secretary’s Office, Rochester, N. Y., April 21, 1862.

Dear Sir: Your favor of the 15th instant, enclosing circular, is received.
J recommend that you get one hundred copies of your circular printed and send
them to E. Creighton, esq., Superintendent of the Pacifie Telegraph, Omaha,

PROCEEDINGS OF THE REGENTS. 81

Nebraska Territory. Mr. Creighton will see them distributed along the line
at the proper places, and will renew the same from time to time with his instrue-
tions. You will please give him particular directions so as to secure what you
want.

I would like to have you send mea few copies after they are printed, that I may
assist you in getting the several telegraph companies between Brownsville, in
Missouri, and Washington, to transmit for you free this class of business for a
limited time at least.

I have written to Mr. Creighton and sent him your circular, but as many
copies will be required they had better be printed, as I suggest.

Yours, truly,”
HIRAM SIBLEY,
President Western Union Telegraph Company.

The following is the circular referred to in the preceding letter, which has
been distributed to the telegraph offices on the line between Missouri and
California: i

Directions for telegraphing storms to the Smithsonian Institution, Washington.
oO oO ’ So

Violent storms usually come from the west—therefore, after a storm ‘has com-
menced, send a telegram eastward, giving
1. The time of beginning of storm.
2. Direction of the wind.
3. Character of the storm, whether wind, rain, snow.

After the storm is over, send the following :

4. Time of ending of storm.
5. Changes of the wind.
6. Changes of temperature.

In accordance with this arrangement the Institution has received occasionally
notices of storms commencing in the Rocky mountains, and even in California.

—_ ’

Sr. Louis, August 14, 1862.

Dear Sir: I believe I have before informed you of Dr. Parry’s botanical
exploration in the Colorado Territory. I have now a long series of barometrical
observations made by him on the different points visited by him, and among
them the snow peaks Mount Guyot and Pike’s Peak. |

From a preliminary calculation I find that the latter rises above Fontaine
qui bouit, at its base, about 7,700 feet; the fountain itself Fr¢mont finds 6,350,
and I about 6,500, so that the peak is doubtless in the neighborhood of 14,000
feet, “snow-capped, but easy of access.”’ The timber reaches to within 2,200 feet
of the top. Mount Guyot is found to be about 13,000 fect high ; Berthoud’s
Pass, 11,400, (all timbered.)

These results, which I think are approximatively correct, show the great
elevation of the base of the mountains, (Denver, 5,300 feet; Mount Vernon,
6,400 feet;) the great clevation of the peaks, and the great height of the limit
of timber. 10,000 to 12,000 feet seems to be that limit between forty and thirty-
five degrees latitude in the Rocky mountains. ;

Very respectfully, yours,
GEORGE ENGELMANN.

Professor HENRY.

6s

82 PROCEEDINGS OF THE REGENTS.

The following remarks relative to this letter have been received from Professor
Guyot, to whom it was submitted:

“T return to you, with my thanks for its communication, the interesting letter
of Dr. Engelmann. I had become acquainted with a part of that information
by a letter from himself. It is exceedingly gratifying to see that interesting
field of labor beginning to be explored. I trust that Dr. Parry will be able to
continue his useful investigations.

' “A creat desideratum for the mountain measurements of the far west is the
determination of some points near the base of the great chains with some degree
of accuracy. We would obtain such points by afew regular baromctric stations.
Could not an observer be found in Denver or Colorado City, for instance, who
would at the same time furnish suitable corresponding observations for measure-
ments in the mountains, which are indispensable for the accurate determination
of the high peaks of the Rocky mountains? It is rather provoking to have the
consciousness that we do not know the true altitude of any point in these
2,000 miles of inland country, within one or two hundred feet, to say the least.

“T suppose that the barometric correction by Plantamour, mentioned in the
report of the proceedings of the British Association, relates to the influence of the
hour of the day at which barometric measurements are made, as derived from
the means of St. Bernard and Geneva. It is the correction the amount of which
1 tried to determine in the latitude of the Black mountain and elsewhere, and
which I apply in all my measurements. It amounts to 745 of the difference
measured, in the hottest part of the day, above the mean, or 3}; if we take the
daily extremes. It is thus of considerable importance, though usually neglected.
I think, however, that the whole needs a considerable revision. ‘i'emperature
is the main cause, but the diurnal variation of pressure also comes in with con-
trary effects.”

Unitep States NATIONAL OBSERVATORY,
Washington City, January 8, 1862.

Dear Sir: You are, I believe, aware that for some time past I have been
engaged in investigations relative to Biela’s comet. In the course of these
investigations I have collected and discussed all the observations that could be
found for each of the recorded six appearances, and, by help of independent
elliptic elements for cach, have digested these observations into a series of
twenty-five normal places, extending though, with wide intervals, from 1772 to
1852. I have also computed rigorously the effect of planetary perturbations
from 1846 to 1858, and am now engaged in continuing this computation to the
next return in 1865. Moreover, I have carefully studied the relative motions
of the two nuclei into which the comet is now divided, and find that the time
and place of their separation can be indicated with a good degree of approx-
imation, thus limiting the field of possible causes of the catastrophe.

It was my expectation, at the outset, to have extended the calculation‘of
perturbations over the whole interval from 1772, so as to unite, if possible, by
a single theory, all the observed places of the comet; but a nearer contempla-
tion of this task, and a little actual trial, show that with my present official
duties this would be a work of many years. It has occurred to me, however,
that it would be in accordance with the plans of the Smithsonian Institution,
and in keeping with the generous interest it has always shown in scientific
investigations, to assist in this work by enabling me to employ a computer, to
whom can be intrusted the more mechanical details of calculation. I venture,
then, to suggest this proposition to you, and if, as I would fain hope, it should
meet your approval, and you authorize me to enter into such an arrangement,

PROCEEDINGS OF THE REGENTS. 83

I will gladly resume the work in accordance with my original plan, and with
renewed hopes of success.
Trusting to hear from you on the subject, I am, respectfully and truly
yours,
J. 8. HUBBARD.
Professor HENRY.

The investigations to which the foregoing communication relates are of a
highly interesting character, and well worthy the assistance of the Smithsonian
Institution. The prosecution of the work has, however, for the present been
suspended.

West Curster, Pa., October 31, 1862.

Dear Sir: For the last two or three years I have been employing and
amusing the leisure hours of my old age in collecting matervals for brief notices
of men and events in my native county of Chester, in the State of Pennsylvania.
I obtained imperfect accounts of about one hundred and thirty men of the
county, who, in their day and generation, had acquired some character and
consequence among their contemporaries of the province from its first settle-
ment, under the auspices of William Penn, down to the present time. ‘Those
materials were, indeed, very defective, owing to the culpable indifference and
negligence of our ancestors in preserving them. But, such as they were, I
endeavored to make the best use I could of them, and caused them to be printed
in numbers, under the title of Noragk CESTRIENSES, in a newspaper of this
village., I cut the articles from the paper as they were published, and arranged
copies of them, in numerical order, in three several scrap-books for preserva-
tion and convenient reference. One of these scrap-books I shall deposit in the
library of the Chester County Cabinet; another will be deposited in the library
of the Pennsylvania Historical Society, at Philadelphia; and the third I pro-
pose, with your permission, if you can allow it the space it‘may occupy, to
put in the library of the Smithsonian Institution, at Washington, with the view
and hope that in each of those depositories, the said Norar may be accessible
to any and every one who may have curiosity enough to wish to refer to them.

My humble memorials of the men of Chester are very meagre; yet, when I
review them, and consider how careless and indifferent our people have been in
such matters, I am surprised even at my own success in gathering my inade-
quate materials for the undertaking, scattered as they were over so extensive a
district.

I am, dear sir, your feeble yet faithful octogenarian friend,
WILLIAM DARLINGTON.
Prof. JosppH HENry.

The foregoing letter is from our much respected and esteemed correspondent
the venerable Dr. William Darlington, of West Chester, Pennsylvania. It
relates to a work performed in,the evening of a long and laborious life, devoted
to the advance of science and the practice of Chiistian love and charity. Its
publication may induce others to render a like service to their neighborhood,
and thus increase the inducements to well doing through the desire inseparably
connected with our instincts of a fwtwre—to live favorably in the memory of
those who may succeed us. (Since this letter was presented to the board Dr,
Darlington has departed this life. Ike died on his eighty-first birth-day, April,
1863.)

84 PROCEEDINGS OF THE REGENTS.

Paris, November 24, 1862.

Dear Sir: Mr. Hermann de Schlagintweit has enclosed me this note for
you, asking me to add something as an introduction, which is scarcely neces-
sary, seeing that he is one of the ‘brothers Schlagintweit whose labors in Thibet
and high India are so familiar to us. Those of the specimens I have seen are
highly | interesting, and the fact that they were collected by the Schlagintweits in
person gives them a full guarantee.

Your obedient servant,

THEODORE LYMAN.

“ Municu, (Bavaria,) November 7, 1862.

Dear Sir: Some days ago I had the pleasure of making the acquaintange
of Mr. Theodore Lyman, who gave me aa interesting facts respecting your
Institution, and especially about your important prrctical and scientific meteo-
rological researches. He also gave me a most lively description of the extent
and the variety of the collections of the Institution: As he has kindly given
me an introduction to you, I take the liberty of addressing you this communi-
cation relative to such parts of our collections of ethnography and natural his-
tory as we are now about to dispose of.

Of the objects mentioned in the accompanying statement, Mr. Lyman has
seen but few, but sufficient, I trust, to enable him to give you more particulars
as to their character if it should be desired, especially as he has had Professors
Kaup and Siebold’s opinion of them.

Besides ae objects of natural history, I may mention the photographic col-
ored fac-similes of a are number of my water-color drawings, their number
amounting to 125, and including only such objects as are not among the plates
published i in our atlas. Mr. Brockhaus has made several series for England,
one for Paris; and two for India, but has a few still remaining in his hands.
The price he charges is 70 thalers, or £10, for thirty views, or £40 for the

series. Mr. Lyman has scen them, and will perhaps be good enough to let you
know in a few words how they are executed, as my deen iption might too easily
be influenced by the fact that I made the originals myself, or wor! ced over those
made by my brother Adolphe.
My address for this winter will be: Dultplatz 10, Munich, Bavaria.
Ww ith the expression of my most sincere consideration, I remain yours,

most tfuly ,
“HERMANN DE SCHLAGINTIWEIT.

Ehnography.—The objects are :

Twenty complete skeletons, head and body, (put up,) of India Thibet, and Turkistan.
poy include savage tribes of India, such as Gonds, Santhals, &c. Price of the original,
£20 to £30 ; of a copy in natural size, color, &c.,in papier mache, £5.

Fifty skulls, without the body, from the same regions. Price of an original, £4 to £6 ;
a copy in papier mache, £14

I mention especially our collection of facial casts, of which I send you the prices of copies
in metal and also in plaster. The metallic casts are better able to resist the effects of time
and exposure, but for a most careful reproduction of any detail the plaster copies can be
entirely relied on. Price in metal, 24 shillings; in plaster, 4 shillings a cast.

Zoology.—We have about fifty large stuffed animals, many in duplicate,among which
are Bos grunniens, Equus hemionus, Asinus onager, male and female, Ovis argali, (ammon,) in
fact, of nearly ali the larger animals of Thibet, one to three specimens of each. Price of
each, £9 to £15.

Of smaller animals. such as Cervus moschatus, the different ovine and caprine domestic
animals of Central Agia, etc., the price is from £2 to £6. Numerousskeletons of mammalia,
put up; price, £2 to £5. "Besides, skulls of Lquus hemionus, £5; of a rhinoceros, from
Bhutan Tarai, £8; of Ovis ergali, £5, &c. An elephant skull, unusually large, with a
weight (198 lbs.) and cranial capacity of about 6,200 cubic inches, determined by filling

L
i

Cc

PROCEEDINGS OF THE REGENTS. 85

it with large shot. The brain of another elephant skull in plaster. It was obtained by a
skull defective in its facial parts, being filled with plaster, and then gradually broken into
small pieces, so that the very foldings of the dura mater remained untouched ; the original
in plaster, £15; a fac-simile in papier mache, £5

I might add details of about 400 species of birds, 2 to 10 shillings, in nearly 1,800 speci-
mens, chiefly from the Himalaya and Thibet; reptiles, 8 shillings to £1, and fishes, 5 to 10
‘shillings, determined by Dr. Gunther, (Proceedings Zool. Soc., London :) butterflies, 20 for
£1, determined by Dr. Moore; insects, 40 for £1, as well as plants and geological col-
lections.

‘The cbjects mentioned are at a country seat of ours, Jaegersburg, near Forchheim, Bava-
ria, not very far by rail from Munich.

CHRISTIANIA, January 6, 1863.

Str: The knowledge of the countries and nations of the earth being particu-
larly useful as well to the mariner as to the trader, it ought to be especially
cultivated by us Norwegians. One of the most effective means of calling forth
the sympathies of the people in behalf of a science is that of establishing public
museums, or collections of objects, presenting immediately to oe eye things of
which no accurate idea or conception can be conveyed by a nere description.
‘The public having thus, so to say, intuitively acquired a fee Tine of interest in
the subject, it will be possible, by united efforts, in the course of some years, to
bring together collections not only instructive to the nation possessing them, but
also deserving the admiration of foreigners.

The British government has in this respect set the greatest example. * * *

An ethnological museum having now been established at the University of
Christiania with the object of il llustrating the manners, mode of living, and civ-
ilization of the various nations, it is to be hoped that the numerous ‘and enter-
prising class of Norwegian seamen will avail themselves of the many opportu-
nities offered on distant voyages to procure objects of interest for such a common
national depository. ‘The managers of the collection have already had frequent
occasions to express their thanks even to common sailors for gifts to the institu-
tion, for which the state has also set apart a sum that, although moderate, will
enable the managers to refund expenses incurred in procuring objects for the
museum. Thus it will be within the. power of any seaman to contribute towards
enlarging the collection.

Trusting to the kind support of the public also for the future, the managers
consider te expedient to lay down some rules for the guidance of those who, ace
the sake of public utility, may be willing thus to contribute towards enlighten-
ing oT fellow citizens:

. The nations and countries, the condition and state of which it will be of
ee ticular interest to see illustrated and exhibited, are especially those most
differing from our own country and our own people; consequéntly, in the
first place, the nations out of Kurope, and, among the Huropeans, those
least known, and of the most antiquated manners. As a rule, objects of
antiquity are also of greater rarity, and will be more acceptable to a col-
lection than things now in use.
2. The objects, suitable for illustrating the condition of such nations, are in-
* mnumerable. Sacred images, weapons, tools used in the principal trades,
clothing, furniture, domestic implements, and products of industry, may be
mentioned. Of course, models, drawings, and especially photographs, will
atford quite as trustworthy information as the object itself. Articles liable
to spoil, or the preservation of which would involve expenses, cannot be
received in a museum.
3. The limited means at the disposal of a Norwegian institution will, as a
matter of course, necessitate the selection of articles the price of which is

8&6 PROCEEDINGS OF THE REGENTS.

not excessive. ‘The exhibition of objects of silver or gold or of regal lux-
uries is also, in fact, of less importance than illustrating the condition of
the people itself.

4. In order, however, that the objects of interest to a museum may be applied
according to their purpose—illustrating the nature of a country or the mode
of living of the people—it will be necessary that every article forwarded
be accompanied by an accurate account of where it was procured ; by what
nation used or made; in what way used, and for what purpose intended.

In order to give this request due publicity, it is desirable not only to assist in

distributing these lines to those who may be supposed willing to advance the
interests of the Institution, but also, perhaps even more so, to make the subject
known by personally applying to such acquaintances as are able to procure
articles of interest.

I remain, sir, yours, very respectfully,

LOUIS KR. DAA.

Tn answer to this circular, the directors of the Museum of Christiania have
been informed that the Smithsonian Institution will co-operate with them by
contributing ethnological specimens from its own collections, and by forwarding
articles of a similar character which may be presented by others.

Newark, Onto, December 8, 1862.

Dear Sir: In the last report of the Regents I notice the Smithsonian In-
stitution proposes to prepare a map of that portion of the United States in which
aboriginal antiquities are found. Feeling it to be the duty of every one to
contribute -to the general fund of knowledge, I take this opportunity of calling
attention to two classes of archeological remains, which I have studied cursorily,
and have not seen described in any work on the subject.

1. Remains of ancient cities and villages in Missouri. I have seen many of
these. Whether large or small, they are similar in character. The remains
consist of a series of tumuli, from one to two fect in height, and varying from
sixteen to twenty-four feet square. ‘These tumuli are in straight lines or rows,
some numbering hundreds, and others, as of villages, tens; the rows cross each
other at right angles, and the little mounds vary from four to cight rods apart.
On digging into these mounds broken pieces of pottery are found, such as ate
commen to all the antiquities of.the country. In one instance an entire vessel
was turned up. About the centre of cach tumulus charcoal and ashes are found.
} have examined several, and the pottery, charcoal and ashes are constants in
all I have opened. Fredericktown, in Madison county, Missouri, seems to have
been the site of a considerable city, extending from a branch of the Castor creck,
which flows cast of the village to near the east fork of the St. Francis, on the
west, being perhaps a mile and a half long and a mile wide from north to south.

2. A different class of tumuli are common in southern Tennessce. ‘The first
I observed at the site of old Fort Pickering, two miles below Memphis. It isa
parallelogram, some 15 to 20 feet high, 120 feet long by some 60 wide, and
surrounded by a great many smaller works, just traccable, of various ‘fancies
and designs. I examined this in the winter of 1847—’48. Last spring I visited
the site of the battle of Shiloh. This system of antiquities was very abundant
there, but not so large as the one near Memphis. In a walk of half a mile I
counted eleven of these parallelograms, generally 60 feet long and 25 wide on
the top. Several of them were appropriated to the burial of our dead, killed
in the battle of Shiloh. The smaller works are innumerable, and are generally
circles. I found them all on the west bank of the Tennessee river; and the

PROCEEDINGS OF THE REGENTS. 87

most interesting on the south side of Owl creek. I noticed one at the
village of Savannah, and a very remarkable circular mound, raised by a gradual
and equal slope from all sides to the centre, which (the centre) I judged to be
about 3 feet higher than the sides, and the diameter of the whole about 100 feet.
I regretted that I had not more leisure to devote to the study of these singular
antiquities, but my mission was one of mercy, and afforded. me little time for
antiquarian research or speculation.

When peace shall be restored to our distracted country, it would be well for
some one or association to pursue a systematic and thorough examination of
all our antiquities, and to trace the progress of those remains from the rude
structures in Canada, south to Central America; for, from my own observations,
T am satisfied that these remains attest a gradual improvement of the race or
races that constructed them from the north to the south. The Missouri cities
and villages were doubtless mere mud huts, and perhaps adobes, such as still
are used in northern and New Mexico, which in central and southern: Mexico
and Central America are improved into structures of solid masonry, with sculp-
tures and hieroglyphies. Whether these were all the work of one race of men
called by some the mound-builders, or of several distinet races, may never be
taiisfactorily settled; but a systematic study of the whole will afiord an in-
seresting chapter in the unwritten history of man.

Truly yours,
I. DILLE.

VALPARAISO, September 17, 1862.

Dear Sir: In reply to your esteemed favor of the 23d July, I beg leave to
state, what I had omitted in my former communication, that the case of
skulls, &c., from Patagonia, was forwarded by me to the care of the United
States Can at Panama, by the British mail steamer, expenses thereon paid
by me in advance as far as Panama. -1 would gladly have done so to the port
of delivery, but found no means of efiecting it. By this time I shall hope that
they are 1n your possession. Sinee you eae an interest in the subject, i
‘shall take an early opportunity of forwarding to the Institute the specimen of

an Atacama mummy—one which I found myself several years ago in the
neighborhoed of the voleano of that name, and which I lefi deposited with a
friend. I have ordered it to be sent to the coast, along with the utensils and
articles of dress and use that were found with the body. At the same time
I shall take the Liberty of adding a few observations explanatory of the cireum-
stances under which these relics are ecncially found, and the probable origin of
the custom. ;

Very respectfully, your obedient servant,
AQ. RIED, M. D.

JosErPH Henry, Esq.,

Smithsonian Institution, Washington. ,

The account of the human remains mentioned by Dr. Ried in the foregoing
letter will be found in the appendix to the present report.

261 GREENE STREET, New York,
November 7, 186
Dear Sir: I enclose herewith a draft of the proposed circular (abilolgea aa
accompanied by the alphabet drawn up by Professor Whitney, and the standard
comparative vocabulary used by Gallatin and Hale. It was at first my inten-

88 . PROCEEDINGS OF THE REGENTS.

tion to modify and enlarge the latter, but on a full review of the subject,
including a list of proposed words, and on consultation with Mr. Shea, I con-
cluded not to do so without reference to yourself. With certain defects it is
yet a very judicious selection, and it has already been used so largely that a
change may now be injudicious. Still, if you think best, I will advise with
Shea, Squier, and Bartlett, and with them prepare a catalogue of additional
words as an appendix. I am of opinion, however, that the instructions will lead
collectors in the right track.

I had also intended to have the circular translated into ‘French here, but the
health of the person from whom I expected, this assistance is too bad to allow
him to do it at present, and I do not wish to detain it longer. I would recom-
mend that a translation be made into Spanish, (Mexican,) French, and German,
both of this circular, if adopted, and the one on archeology. 'Yo save trouble
with the vocabulary, I send a duplicate blank. ‘There are many French priests
both in:the Hudson’s Bay country and in Oregon; the Spanish, or rather Mexi-
can, priests in New Mexico, California, and elsewhere, may prove valuable
assistants, and among the Germans, even many soldiers in ,the army, are excel-
lently fitted to collect, and well disposed to do so. It will be well to send a
number, say one hundred copies, to the Bureau of Indian Affairs, to be distributed
among the agents; an additional hundred to the Bureau of Topographical Engi-
neers; a like number to the Surveyor General of the Land Office, for the use of
his department; and to the Secretaries of State and of the Navy, for distribution
among our consuls and officers bound to the western coast of Mexico, and-else-
where. ‘The governor of the Hudson’s Bay Company can, I presume, be also
interested in the subject, and though last, not least, the governor of Russian
America.

One thing that eseaped my memory in preparing the archeological cireular,
was to say that due credit would be given to collectors. It will be better, how-
ever, if you prefix the whole by an official notice emanating from yourself to
this effect. An acknowledgment from the head of an institution like th
Smithsonian is a great inducement to exertion.

I see in the last annua] report Mr. Morgan’s circular respecting an areheo-
logical map. HH you recoilect, this was one of the points which I proposed to
embrace in my work. I think not only of: preparing a genera! map of North
America, embodying the great families, but special maps of particular districts
inhabited by a large’ number of tribes, inciuded in a few families, who live
within a small space. Such are Russian and British America, Washington
Territory, Oregon, and California, for all of which I possess minute information.
Mr. Bartlett has furnished me with the ranges of the New Mexican and ‘Texan
tribes, and I have material from other sources covering other parts of the
country. Of course, all this, with the consent of the bureau, will belong to the
Smithsonian, and I have no wish to monopolize the merit of such a work; but
as I know that no one else possesses the material that I do, at least of the
country west of the Rocky mountains, I should be unwilling to relinquish to
another so important a task. Besides this, until the comparison of the languages

is completed, the ethnological part of the map cannot be perfected.

- J would, therefore, suggest that skeleton maps be issued, as soon as prepared,
to various persons interested in ethnology, and who are familiar with particular
regions, to be filled up with such information as they may possess, to be after,
wards reduced, giving to each the credit of his contributions. Mr. Shea, Mr.
- Bartlett, General Charles P. Stone, Mr. Buckingham Smith, Dr. Hayden, and
other gentlemen, can all add largely to such a work. I have already trans-
mitted departmental maps to each ‘Territory, under the sanction of the Indian
bureau. Permit me, further, to recommend that the proposed map should
extend far enough north to embrace all the EKsquimaux tribes; and west, to take
in the sedentary P'chuktchi or Namollos of Russian Asia.

PROCEEDINGS OF THE REGENTS. 89

T am very much afraid that the amount of information proposed to be con-
tained in the ethnological map will render it confused. I would suggest whether
it would not be better to have tao maps—one showing the character of the
country, whether forest or prairie, desert or arable, with the isothermal lines, &c ;
the other, its counterpart, containing merely the principal topographical features,
such as the rivers and main chains of mountains, upon which the boundaries
and names of the tribes and local names should appear. 'The first might indeed
have designated upon it the boundaries of the families, but should not be colored.
‘Lhe latter to be colored and show the tribal subdivisions.

Begging to apologize for the length of this communication, I am, very truly,
your obedient servant,

GEORGE GIBBS.

Professor JosrpH HENRY,

Secretary Smithsonian Institution, Washington.

Novemeser 18, 1862.

In regard to the proposed map of the continent mentioned in your letter of
‘the 13th, I have the honor to submit the following suggestions : ‘The prepara-
tion of-a base map to serve for these various uses is a subject of the greatest
interest to every one concerned in scientific pursuits, and will form a lasting
monument of the wisdom and efliciency of the Smithsonian Institution. The
urgent need of such a one is evident from the fact that I have been unable
to procure in this city a tolerably correct and recent map, embracing the whole
continent on a scale of convenient size for ethnological purposes, and have actu-
ally been compelled to send to Germany for one, The scale recommended by
Mr. Morgan strikes me as very suitable. In my remarks upon his propositions
J meant only to object to. the introduction upon a strictly ethnological map of
the details of topography, meteorology, and hypsometry. My own idea, in
which I am supported by other gentlemen engaged in the same pursuit, is, that
an ethnological map should exhibit the principal features of the country, the
rivers, moyntain chains, and particularly the passes in the mountains, and the
great Indian trails, where the nature of the country was such as to render these
fixed and distinct; that it should also have the nomenclature fully given, in the
popular form to enable collectors in the field to decide upon exact localities, but in
such a type as to distinguish the popular from the true Indian names. Where,
as I shall presently suggest, sectional maps on a larger scale are prepared, this
nomenclature may, however, better be confined on the general map to a few main
objects, such as the larger rivers, in order to avoid perplexity. Political divi-
sions should be as few as possible and faintly indicated. Indeed, in an ethno-
logical point of view, they are almost worthless, as ours are generally arbitrary
and not founded on geographical features.

Besides this general map, I would also have-a series of maps on a larger
scale, comprising particular sections of country, having direct reference to
the distribution of tribes and familics. ‘Thus, for instance, one map might
show the country occupied by the different tribes of the Dakota, another of the
Snake or Shoshonee, &c. The advantage of this would be, that whereas in the
general map a single color must be used to indicate a great family, composed ot
numerous tribes, and its subdivisions could not be indicated without leading to
confusion, these collateral maps could be made to exhibit the districts occupied
by each. This is very important where the languages spoken by various tribes
differ greatly, as among the Snakes, the Bannak from the Ute, and that from ,
the Comanche. The scale on which these sub-maps should be constructed
would vary greatly, depending upon two points: first, the number of tribes oc-
cupying a given region; second, upon the amount of minute information likely
to be acquired. On the western coast of America, or that district lying between
the Cascade and Sierra Nevada mountains and the sea, there are a great number

90 PROCEEDINGS OF THE REGENTS:

of tribes, speaking quite a number of absolutely different languages, and of
some of thes se there are various dialects, differing sufficiently to require de-
signation. Having fixed and permanent villages, their nomenclature will be
much more extensive than what we are likely to get from nomadic bands who
roam in large numbers and cannot be followed up. The same state of things
existed on the Atlantic, and of portions of the country we have still quite ric
historical material. |

You will see that the above will contemplate, in fact, an ethnological atlas, and
that its préparation will be a matter of much time and labor, and occupy the
attention of all those interested in the study. As regards expense, that need
not be great at any one time, for the sub-maps, like the general one, might, in
the first place, be prepared in skeleton, and distributed like the circulars to in-
vite inquiry and contribution of material. As the work progresses, the topog-
raphy may be filled in, for these maps will afford room to exhibit it in much
greater detail than the larger one.

In fact, as regards a eeneral map, even upon the scale proposed, and foy pur-
poses of topography itself, I doubt the propriety of going greatly into details.
‘The best general European maps avoid this. The map of the Pacific railroad
explorations, prepared under Mr. Davis’s instructions, is almost useless from its
very minuteness. All the principal features are lost in the details of topography.
But, above all things,it appears to me that multiplicity of object should be
avoided. Of course, a map showing the amount of rain per annum should ex-
hibit the causes of variation in different districts, but this depends on great
features and not on minute ones; and until it is shown that magnetics, fer in-
stance, influence the amount of precipitation, it would be improper to introduce
lines of equal variation on a map intended to show those of equal rain fall. So
with a general topographical or ethnological map.

T am engaged, with the assistance of the others, in drawing up the details
which we think it would be well to include in the sub-maps, indicating the bound-
aries and scales, which I will forward, as scon as completed, for your considera-
tion. Of course, I do not know how far you may be inclined to extend this
subject, but the inquiry will at any rate be the means of ascertaining some
valuable facts as to the amount of information at hand.

This leads me to another subject. I find the field which I at first proposed
to mysclf has increased to such formidable proportions that, on consultation
with Myr. Bartlett and others, I have concluded to propose the following
scheme in its place: Professor Henry to request Messrs. Bartlett, Shea, Squier,
Buckingham Smith, and such others as he may think fit, to unite with the
writer in a comprehensive work upon the ethnology and philology of North
America, to be published by the Institution, and to prepare materials for maps
showing the location of the Indian tribes at various periods. The work can
appear in parts, if thought advisable, as cach finishes his portion. Mz. B. R.
Iioss would doubtless undertake British North America, (except the immediate
coast,) including the Chepewyan family, the Crees, and Knistencaux, and he
haps the Esquimaux, and prepare a memoir giving the history of the subjec
and all that is valuable regarding those tribes. Mr. Shea to take the cane

east of the Mississippi, except Geor gia and Florida, which might be assigned to
Mr. Smith. Shea’s knowledge and material exceed those of oa one, on the
people of this ssh and his critical acumen is remarkable. Mr. Squier would
assume Central America, and Mr. Bartlett, Texas and New Mexico. ‘The writer
to take the northwest coast, Washington Territory, Oregon, and California.
There would remain the country intermediate between the Mississippi and
Rocky mountains and Mexico. Mexico I would suggest should be assigned to
some of the ethnologists of that country, with an invitation to prepare a general
view of the subject as relates to it.

The work should embrace histography, ethnological divisions of families,

PROCEEDINGS OF THE REGENTS. 91

founded on comparative philology, habits, &c., and psychology—in fact, to
have as wide a range as there are reliable materials to work on. As it would
take too long to await its entire completion, it might appear in a series of mono-
graphs, such as you have already published on various subjects, but the field is
too wide for any one man to undertake an exhaustive work, embracing -the
whole.

I should explain that this suggestion comes entirely from myself, and that I
am led to it by consultation with these gentlemen as to their views of the
demands of ethnology in a work of this kind, not that they desired to invite
such a request.

GEORGE GIBBS.

DECEMBER 26, 1882.

I had the honor to receive, in due course, your letter of December 18,
informing me that the questions submitted in mine of December 3 had been,
referred to Professor Whitney, and shall hope to hear from him in reply.

Pursuant to the directions I received in a former letter, | wrote to Dr. Davis,
requesting him to make any suggestions which might occur to him in regard to
the archzologieal cireular; but having received no reply, I presume that he is
absent from the city. I called on Mr. Squier, who promised to send me his
views on the same subject, but have not yet received them. I mention this a:
the cause of the delay in communicating the result to you. If I do not hear
from you to the contrary, I will let the circular stand as it is.

In accordance with your desire that I should prepare a list of additional
words to accompany the philological circular, 1 have gone into one at some
length, in concurrence with Mr. Shea. We agree in submitting to you that the
publication of this additional vocabulary be deferred for the present, and appear
hereafter as a sort of supplement, when we shall have rendered it tolerably
perfect. It may be advisable to extend it to some two thousand or twenty-five
hundred words and phrases, some of them generally applicable, others to only
particular parts of the country. The reason for this extension is as follows :

As regards nouns, the almost entire absence of generic terms renders it
necessary that each object should be as specifically designated as possible; for
instance, each particular kind of animal, tree, &c. Mr. Morgan’s circular illus-
trates this point in respect to relationships, which are distinguished by singular
complication and a great variety of names. In the pronouns there are not only
absolute but copulative pronouns, sometimes both personal and possessive, the
copulative being joined to or incorporafed with nouns and adjectives or verbs,
as the case may be. In some languages, at least, there are two and even three
sets of cardinal numbers, one being positive or simple, another personal or
applied to men, and still another to the counting of money. Again, of the
verbs, the degree of detail into which these languages run may be seen from
the fact that while there may be no abstract word for “to wash” or “ kill,”
there will be found separate words for to wash the hands, face, and clothes,
and to kill by stabbing, shooting with a bow, gun, &c.

You will therefore perceive that in order to arrive at any degree of precision
it will be necessary to furnish quite a numerous collection of words, and that
reference must be.had in the selection both of these and the phrases to the
idiom of the language and turn of thought of the speaker. ‘lo accomplish this
in a way satisfactory to yourself will require some time, but in the mean while
the present circular will perform its own more limited task.

The scientific names of animals, &c., should, of course, be given; but whether
it will be best to undertake a translation of the whole into other languages is a
question, for there are many words of daily use in Indian life which have no
Synonyms in dictionaries, or except in the various patois.

92 PROCEEDINGS OF THE REGENTS.

DECEMBER 26, 1862.

IT owe you an apology for my omission to comply with your request that I
should send you an account of what I am doing. It is, in brief, this:

I propose to give a connected sevies of vocabularies of all the known Indian
languages west of the Rocky mountains, deriving from them a classification of
the various tribes into families, and upon this basis to, form an ethnological map
of that part of the country. In addition to this, I propose to give a memoir
upon the character, customs, &c., of those tribes with which I have been in
direct communication, more especially as regards their habits of thinking,
mythology, &¢., aud to include or append sub-memoirs by other persons upon
particular districts out of my own range, and a résumé of the statistics of popu-
lation at various periods so far as known. Of course the various authorities
will be referred to, so as to give the bibliography, history, &c., of each section.

I have limited the above mentioned to the country west of the Rocky mount-
ains, because I am satisfied that it is all that [ can accomplish within a reason-
able time, and that the labors of several investigators are required for an
exhaustive discussion of what. has already been collected in various parts of the
continent. In a former letter I took the liberty of suggesting the allotment of
other parts of this work to several gentlemen who have pursued separate exam-
nations; such as Mr. Squier for Central America; Mr. Bartlett for Texas, New
Mexico, and Arizona; Mr. Shea for the Atlantic section, except Georgia and
Florida, which should fall to Mr. Buckingham Smith; and Mr. B. R. Ross, of the
Hudson’s Bay Company, for British America, except the northwest coast, which
would come within my own field. Mr. Smith suggests El Exmo. Seftor Don
Fernando Ramirez, of Mexico, as the proper man to give the Mexican part, and
thinks that he would willingly undertake it. It appears to me that the calling
in assistance from Canadian and Mexican sources would not only add value to
the contributions, but be a matter of policy as regards the Institution itself,
making it a North American centre, instead of one confined to the United
States alone. I need not say that the value of the ethnological series which
you may publish will be greatly enhanced by the fact that each contribution is
a specialty. It would, moreover, give the opportunity to make each paper
exhaustive within its own region; Sefior Ramirez, for example, giving the
literary history of the Mexican tribes, as well as their philology and ethnology.

Mr. Ross’s vocabularies, together with Mr. Kennicott’s, are of-the utmost
importance in furnishing materials for comparison between the northern Che-
pewyan languages and the southern b®mches, which extend into New Mexico
and Chihuahua. His notes are carefully prepared and well written. If you
deem it desirable, I will forward them for your examination.

GEORGE GIBBS.

JANUARY 20, 1863...

T herewith enclose a memorandum of what is doing in the way of ethnology,
so far as I am informed.

Mr. Shea has two more numbers of his series out, copies of which will imme-
diately be sent you. One of them is the vocabulary of the San Antonio mission
Indians, the one which Mr. Taylor denominates ‘‘Sextapay,” bus the: correctness
of which title is questionable. Mr. Shea has edited this with great care, re-
arranging the whole, as the manuscript was in a confused state. I beg to refer
you to his preface, as also to the appeal at the end of the work. The other is
Mr. Smith’s Nevome. ; s

The Sextapay, or San Antonio, is one of the numbers due on your contribu-
tion for 1861. Its publication has been delayed by the labor incident to putting
it in presentable form, and by the necessity of casting some special type. This,

PROCEEDINGS OF THE REGENTS. 93

together with the Mutsun and Yakama grammars, fills the programme for that

ear.
. On your subscription ie 1862 (on which no payment has yet been made)
Smith’s Nevome is the first. The vocabulary of the Mutsun is now going
through the press, and will be immediately followed by a number containing
three “of my larger vocabularies, the Chinook proper, the Clallam, and the
Lummi, the last iano being languages of the Selish family

Shea proposes to follow up for 1863 with the Mohawk radicals, a valuable
Jesuit manuscript, a Jesuit grammar of the Micmac, and my dictionary of the
Nisqually. 1 trust sincerely you will find it-convenient to continue your aid,
for 1 am not alone in considering this the most valuable series of philological
publications now going on. My. Moore, the librarian of the New York His-
torical Socicty, recently told me that neither England nor France could show
anything to equal it.

The Chinook jargon is now finally in hand, and I trust to send you the
proofs of the first signatures this week, as also of the circulars.

GEORGE GIBBS.

JANUARY 21, 1863.

Mr. Buckingham Smith called upon me to-day and showed me a letter from
Don José Fernando Ramirez, of Mexico, from which [ enclose an abstract:
“There exist no vocabularies of the languages, nor have the grammars ever
been preserved, written by the early missionaries. It is almost. impossible to
_ bring together those that have been printed. On this subject a work has been
commenced, entitled ‘Cuadro deseriptivo y comparativo de las lenguas indigenas
de Mexico,’ compendium descriptive and comparative of the native tong es of
Mexico, by Don Francisco Pimentel. The first volume only has been printed,
which comprehends the analysis of twelve languages. Unfortunately, material
is wanting. Those contained in the first volume are the Huaxteco, Mixteco,
Mame, Othomi, Mexican, Zapateco, Tarahumar, Tarasco, Totonaco, Opata or
Teguema, Cahita, and Matlaznica. If you have succeeded in publishing the
grammars of which you informed me, (Pima and Sleve,) and they should arrive
in time, they will be examined in the work. I have not and am unacquainted
with the ‘Archeology of the United. States, by Samuel F. Haven,’ about which
you write me. Of the Smithsonian Contributions I have only the sceond, third,
-and fourth volumes, unless the first volume should be ‘Ancient Monuments of the
Mississippi Valley,’ which I possess. At present there is no way of sending
books to Mexico, unless the Department of State will take charge of them.”
Mr. Smith has handed me the above with the view that I might ask of you to
send to Setior Ramirez such other. papers of the “Contributions” as belong to
archeology. That gentleman is well known as one of the most distinguished
scholars in that department in Mexico, and one whom it would be’ desirable for
the Institution to number among its correspondents. I am, however, astonished
at the account he gives of the paucity of works on the indigenous languages of
that country, so entirely opposite to our general belief here. "Under any circum-
stances, Pimentel’s work should be procured if possible.
Lam, sir, very respectfully, your obedient servant,
GEORGE GIBBS.
Prof. Josep Henry,
Secretary to the Smithsonian Institution.

New Yorn, November 1, 1862.
Dear Sir: The Indian works now printing and to be completed before the
close of the year, beside the Sextapay or San Antonio vocabulary, are:
I. The Mutsun vocabulary of Padre Felipe Arroyo de la Cuesta. This is a

94 PROCEEDINGS OF THE REGENTS.

collection of phrases, but seems to include all the known words of the language,
and, with the grammar already printed, will furnish all necessary means of com-
paring the language with others. To complete the subject, nothing will be
needed but good comparative vocabularies of the Soledad, and other dialeets.

Il. The Micmac grammar of M. Maillard. Mr. Gallatin drew some ideas
from an extract from fragments of this, but the entire work is necessary as the
best known treatise of the most easterly branch of the Algonquin family.

III. The radical words of the Mohawk language by Rev. James Bruyas.
This work treats the language on the system introduced by the Port Royalists,
of learning the roots or radical words of a language and then deducing the
derivatives. It divides the whole language into conjugations, and gives under
each root the derivatives with many examples.

IV. An alphabetical vocabulary of the Chinook language by Mr. George
Gibbs, in all probability the largest that will ever be made, as the tribe is fast
vanishing, I have also in hand, and may have ready in time, some others, as—

V. Vocabularies of the Klallam and Lummi, by Mr. George Gibbs.

VI. A Névome or Pima grammar, edited by Buckingham Smith, esq.
Next to ¢hese I wish to bring out—

VII. A Nisqually dictionary, by Mr. Gibbs.

Vili. An extremely valuable and ample dictionary of the Illinois language,
_compiled, [-judge, by the Rev. Father Le Boulanger, and for extent, clearness,
and variety, one of the most important labors of the kind known to us.

IX. Huron radical words by Father Carheil, revised by Father Potier, also
a very ample and important work. Nos. 8 and 9 will each form a volume of
500 pages, such as the Onondaga dictionary published by me, and their publi-
cation is an undertaking of such magnitude that it can be carried out only by
the active co-operation of those interested in philological studies.

I thank you for the information as to the forthcoming Cree grammar, which I
will make note of in the Historical Magazine.

Your obedient servant,

JOHN GILMARY SHEA.

Devon, SASKATCHEWAN, Hupson’s Bay TERRITORIES,
July 4, 1862

Sir: I beg to forward to you the enclosed schedule, which I received about
a fortnight since, and have now filled up according to the request of L. H.
Morgan, esq. I have had some little difficulty in ascertaining the precise word
for some of the relatiouships noted down, but I trast that the results of my
investigations will be as free from error as.can well be expected, and that the
paper as now returned will meet the wishes of the gentleman who sent it to me.
‘The postal arrangements of this country are in, so primitive a state that I fear
some months will elapse ere this letter and the enclosure reaches you; but it
shall be despatched from here by the first opportunity that may oceur. JI have
been living amongst the Cree Indians for ten years, and have long been so far
acquainted with their language as to be able to preach to my congregations
extempore. For some time past my scraps of spare time have been devoted to
the work of compiling a dictvonary of the native tongue, as nothing of the kind
is yet extant, and my own experience in past years has taught me that it is
greatly needed. I have now completed the first part, namely, the English-Cree,
which contains very nearly 6,000 English words, with their corresponding
Indian terms, and numerous idiomatic expressions; but I have still sufficient
to occupy my disposable hours for many months in order to complete all that
I contemplate. A friend had advised me to apply to yourself respecting the
publication of the work when finished, and it was my intention to do so; but as

PROCEEDINGS OF THE REGENTS. 95

the failing health of Mrs. Watkins has compelled me to seek permission to visit
England next summer, I have declined doing so, as probably the Church Mis-
’ sionary Society, with which I am connected, may undertake to carry the work
through the press while I am in my native land, and have the opportunity of
correcting any typographical errors which may be made in the proof-sheets.
Still you will perhaps allow me to ask if the Smithsonian Institution is in the
habit of publishing such books as dictionaries of the native languages, and upon
what terms it undertakes to have them printed, as I have no means of ascer-
taining this point. If you have any circular or pamphlet at hand explanatory
of the principles and aims of the institution with which you are officially con-
nected, I should feel much obliged by your kindly forwarding one to me.
Believe me, sir, yours, very obediently,
E. A. WATKINS.
Professor Henry.

The writer of this letter was informed that the Institution does publish works
of the kind mentioned, if approved by a commission of examination, provided
that no other means exists of bringing them before the public.

Deer Crees, NEBRASKA TERRITORY,
September 19, 1862.

Honorep Sir: As I am unable to express myself in English as well as is
necessary and as I wished, I take the liberty of sending a German letter, and
beg for a kind excuse and acceptance of the same.

When I arrived here two years ago, unfortunately, immediately after the
disappearance of the missionary Brunninger, | found some publications of the
Smithsonian Institution relating to various observations. . 1 regret that I wa:
neither in a position to read them cursorily through, nor had I time to even
grasp their contents. When, however, time and other business did permit, 1
looked into them carefully and found great pleasure in so doing, for which reason
I also recognize it as my duty as far as I am able with my feeble powers to
show my gratitude. Only I must also add with much regret that understanding
and apparatus are wanting to me in many branches. Because, however, | stand
here so ignorant, I considered it to be well and necessary first to ask whether
or with what subjects I could render to your honored institution my feeble
services. One point which I in the first place considered as appropriate is the
language of the Shyenne Indians. I have now passed a year with them in a
capacity which is well known to you, and for a quarter of a year I have travelled
about with them for the purpose of learning the language, but have still learned
comparatively little. I permit myself, however, to contribute to your honored
institution a small extract from the treasure which I have learned and collecteg
for their kind consideration. Should it be aeceptable to your honored institu-
tion, I will, if you desire, send more. In the mean time I remain, honored sir,
with the highest esteem, your obedient,

GEORGE FLACHENECKER,
Evangelical Lutheran Missionary.
To the SMITHSONIAN INSTITUTION.

Honouuvuu, July 15, 1862. .

My Dear Sir: J am in receipt of your favors, dated April 14 and 21, en-
closing an order from Professor Bache for tidal apparatus, which | forward to

96 PROCEEDINGS OF THE REGENTS.

San Francisco by this. mail. I am in hopes to receive it, for I am not aware

that any observations have ever been made, at a position similar to that of a.

islands, a long distance from a coast line.

I have also received the reports of the Smithsonian Institution for the years
185460, check lists of American shells, and catalogue of publications of socie-
ties, for which I beg to return my sincere thanks.

I forward you, per this mail, a catalogue of the works in my library relating
to the Sandwich Islands, which I believe to be near, if not quite, complete.
You will notice in it three periodicals, formerly published at our islands, not in
your catalogue. They contain a few scientific articles. Please look over the
catalogue, and any works published here which you may wish to obtain, please
inform me, and if possible, they will be sent you.

Your wishes in regard to a series of shells described by me shall be attended
to. I also shall furnish you, as soon as I can obtain it, a specimen of the bat
living on our islands, (the only indigenous mammal here,) for the reason that
I received a letter by last mail from Dr. Gray, of the British Museum, acknowl-
edging the receipt of one from me, which he decides, after a hasty examination,
to be identical with a species common to the east and northerly part of America,
usually called the “New York Bat.” He was to exhibit it at the meeting of
the Zoological Society the evening of the day he wrote me. If he is correct, it
will be a singular exception to the laws of animal distribution.

I am about to commence the publication of a serial work in England, on the
Natural History of the Pacifie Islands, which will be furnished you from there.

My illustrated catalogue of the shells of the Sandwich Islands and their
animals must be deferred for a time, as my collector on the islands south of the
equator, who has been occupied near three years in searching them, informs me
that he has been very successful, having obtained 600 new land and marine
species, and discovered facts of great value to me in regard to distribution of
specics, &ec.

1 notice in your report of 1860 an annotncement of the intended publication

of several pamphlets on shells, three by Mr. Carpenter. The one on west coast
species and one on United States expedition shells I particularly wish to see, as

the latter I shall be able to correct. All pamphlets, however, on shells will be.

of use to me.

I beg strongly that duplicates of shells from the Indo-Pacific provinee may
be sent me by the Institution; full value will be returned. Are there none left
of -Wilkes’s e2 xpedition, or of Rodgers’s Japan expedition ?

All packages in future, please address to me and forward to Wells, Fargo &
Co., New. York.

Do not fail to make use of me in any way you may consider of value to the
Institution.

Yours, most truly,

d W. H. PEASE.
Professor Joserpu Henry.

The books and specimens referred to in this letter have been received at the
Institution. The species of bat so remarkable, as being the only native mammal
found on the Sandwich Islands; has sinee been identified by Dr. Gray, of the
British Museum, as the Lasiurus Gray?, belonging to the coast of Chile.

HEADQUARTERS, GENERAL GRANT’S ARMY,
Jackson, Tennessee, November 5, 1862.

Dear Sir: A large and perhaps valuable, but incomplete, herbarium has
fallen into my hands, “captured from the confederates, or, at least, belonging to

PROCEEDINGS OF THE RIGENTS. 97

some institution of learning, and wanting an owner. It consists of about a dozen
thick folio volumes of plants belonging principally to West Tennessee, very neatly
arranged. ‘They were gathered together by a friend of mine, and as the soldiers
were destroying them, J have taken charge of them, with a view of presenting them
to some scientific institution. Please inform me if it would be worth while to
send them to the Smithsonian Institution, and let me know whether I shall for-
ward them by Adams’s Express, so that they will go safely, and whether I must
pay the charges, &c.
Respectfully, &c.,
H. R. WIRTZ,
Surgeon United States Army, Medical Director.
Professor Henry,
Smithsonian Institution.

P. S.—I have them in a box about 3 feet by 24.

The collection of plants above referred to has been received, and will be
carefully preserved separately until the close of the war. No information has
been obtained as to the original owner or collector.

Leipzic, May 31, 1861.

My Dear Sir: In sending back, through Dr. Fliigel, agent of the Smith-
sonian Institution, the ferns which have been communicated to me by Dr.
Eaton, in your name, I cannot omit to express my warmest thanks, not only for
the kindness shown me in this instance, but also for the collection of ferns des-
tined for the herbary of the university.

I am under a great obligation to the Institution for having given me an oppor-
tunity of examining these ferns, whereby it has materially assisted me in my
studies.

Accept the assurance of my deepest gratitude and the highest esteem.

Yours,
G. METTENIUS, Professor.
Professor Dr. Henry,
Secretary of the Smithsonian Institution.

The ferns sent back are the uniques of Brackenridge’s collection, and will
be placed with the rest of the collection now in Dr. 'Torrey’s hands.
DANIEL C. EATON.
New York, January 13, 1863.

GENEVA, Switzerland, May 25, 1862.

Dear Sir; Your letter of the 28th of February was duly received, and that
it has not been sooner answered must be ascribed to the throng of pressing oc-
cupations in which | have been absolutely absorbed. I am under great obliga-
tions for the interest which you have been pleased to take in procuring for me
the books and duplicata of your mammifers which I had requested.

In regard to the catalogue of the Hymenoptera, I regret to say that I have
not reached it, having been engrossed by various other labors. I have com-
menced a large work on America, of which I have had the satisfaction of send-
ing to the Smithsonian Institution the two first parts, the Crustacea and the
Myriapodes. Since then I have been engaged with the Orthoptera, and have
proposed next to proceed with the Hymenoptera. The plates of the Orthoptera
will be forthwith sent to the engraver, but [ have been dreadfully retarded by
a succession of mishaps. My original draughtsman died; another whom I had

78

98 PROCEEDINGS OF THE REGENTS.

trained quitted this service to engage in that of the railroads; a third found a
lucrative place and left me to shift for myself, and the fourth threatens to do the
same thing. Nevertheless, I hope to get through some day or other.

My taxidermist, whom I had left in Mexico to complete my collections, after
having done nothing but cajole me for several years, has ended by leaving the
country without sending me anything of consequence. All this has greatly
hindered me. Still, my descriptive treatise on the Vespide of America is ready,
but I wish to revise the manuscript and correct it from beginning to end, for it
is my custom to leave my manuscripts in the drawer for one or two years and
then remodel them by means of the materials I have in hand. It is only in
this way that zoological works can be worthily composed. If you are urgent,
however, I will leave the Orthoptera in order to take up the Wasps and will
send you the manuscript this winter. Please indicate to me your wishes on this
subject.

As to the other families, I cannot undertake them till I have done with the
Orthoptera and the Wasps. But as you seem in haste, I think your best course
would be to intrust this work to some American whose special line of study
lies in that direction, and Mr. Edward Norton is well qualified for it. With the
same view I have already prevailed on him to take in hand the Ichneumonide.

It would be impossible to make purely and simply a catalogue of the Hyme-
noptera. The number of known species is much too restricted. ‘There would
be needed a descriptive work, and you could not acquit yourself of it under
less than ten large volumes. ‘The labor upon the Hymenoptera is a colossal
one. When I shall have published the Wasps, I will see whether I can under-
take another family for you, and believe that 1 can; but, trust me, you must
proceed by families or you will have nothing satisfactory.

I take this opportunity of informing you that in July I shall forward to you
a package containing three memoirs of mine and my map of Mexico; and in
addition, certain books for several learned Americans. Have you Saussure’s
Treatise on Hygrometry? Be so kind as to have the books distributed accord-
to the address of each.

Please accept, dear sir, my cordial good wishes and the expression of my entire
esteem.

D. H’Y DE SAUSSURE..

P. S—If you have still any Vespide to send me to complete my manuscript,
it will be necessary to do so soon, that I may be enabled to employ them as
matcrials. My manuscript will form a volume in 8vo.

You will inexpressibly oblige me if you will have the recent American work
on Tehuantepec sent to me.

We have since learned that the manuscript work on the Vespide or Wasps
of America, mentioned in the foregoing letter, has been completed. It will be
published as soon as practicable after it has been received and translated from
the French

New York, September 16, 1862.

Dear Sir: My brother wishes me to address you in regard to a cabinct of
minerals which he would like to seld to the Smithsonian Institution. He has a
collection of minerals, mostly Californian and Mexican, between 2,000 and
3,000 in number, and containing about $1,500 in gold and silver. His reason
for selling is, that it is entirely too valuable to retain in his office, as he is afraid
of being robbed. He asks $3,000 for it, and refers to Professor Whitney, of
California, for an examination.

You would confer a favor by returning an answer to this note when conve-

PROCEEDINGS OF THE REGENTS. 99

nient; and perhaps, if the Smithsonian Institution does not want the collection,
you may be cognizant of some other institution which might desire to obtain it.
Very respectfully, yours, &c.,
Professor HENRY.

The foregoing is one of many propositions to sell specimens of natural his-
tory, &e., to all of which the answer has been made that the Institution does
not purchase articles of the kind.

The following letter was received from M. Romero, Mexican minister, in
reply to a request made to him to furnish a letter to facilitate the explorations
of Mr. Xantus, in Mexico:

WASHINGTON, December 4, 1862.

Dear Sir: I have the honor to acknowledge the receipt of your letter of
the Ist instant, informing me of the object of the appointment of Mr. John
Xantus as United Gates consul at J eae and asking me to furnish him
with such letter of mtroduction for the governors of the States of Colima, Mi-
choacan, and the adjacent ones, as may help him in the prosecution of the scien-
tific investigations he intends to make in a portion of western Mexico whose
natural productions are very little known.

Being desirous to contribute to the success of Mr. Xantus’s scientific researches
and labors, I enclose you herewith letters of introduction for the governors of
the States of Michoacan, Jalisco, Colima, and Sinaloa, which I hope will fully
answer his purpose. Should he desire letters for any other governor, I will
furnish him with them as soon as you let me know it.

As regards the entrance of the scientific apparatus Mr. Xantus may take
with him to be used in making collections in natural history for the museum in
charge of your Institution, 1 am happy to say that I think he will not have
any difficulty with the customs authorities at Manzanillo, such articles being free
from duty according to the Mexican tariff.

I am, sir, very respectfully, your obedient servant,

M. ROMERO.

Professor JosepH Henry, .

Secretary of the Smithsonian Institution, &e

UL: O.G x

ON

HON. JAMES A. PEARCE, OF MARYLAND,

ONE OF THE REGENTS OF THE SMITHSONIAN INSTITUTION,

BY

Pror. A. D. BACHE, LL. D., Superintendent of the U. S. Coast Survey.

Ata meeting of the Board of Regents of the Smithsonian Institution, held
January 31, 1863, Professor Henry, the Secretary, announced the death of
Hon. James A. Pearce, one of the Regents.

Prof. Bache, after appropriate remarks, offered the following resolutions, which
were unanimously adopted :

Resolved, That the Board of Regents of the Smithsonian Institution deeply mourn the loss
of their distinguished fellow-regent, JAMES ALLRED PEARCE.

Resolved, That inthe death of Mr. Pearce our country has lost a refined and influential
citizen, the Senate of the United States an able, judicious, honest statesman, and this institu-
tion an active, intelligent, and learned Regent.

Resolved, That we sincerely condole with the afflicted family of Mr. Pearce, and offer to
them our heartfelt sympathy in their great bereavement.

Resolved, That a copy of these resolutions be communicated by the Secretary of the Smith-

sonian Institution to the family of the deceased.

On motion of Mr. TrumMBULL, it was—

Resolved, That Professor Bache be requested to furnish a copy of his remarks in relation
to Hon. James A. Pearce, for insertion in the journal of the Board of Regents.

Heo yy:

Again has death invaded our circle, and taken from our councils and our
active sympathies one of the most admirably gifted intellects which has at any
time been called upon to shape the destiny or direct the labors of the Smith-
sonian Institution. A member of the executive committee from nearly the sce-
ond year of the organization under the act of Congress of 1846, attentive to
every detail, whether scientific, administrative, or financial, Mr: Pearce was
always prompt at the call of every duty. His entire and cordial acquiescence
in the form of organization adopted for the Institution, his liberal and zealous
co-operation with the Board of Regents, his earnest support of, and unfaltering

EULOGY. 101

confidence in, the discretion and integrity of its Secretary, were as conspicuous
as they were productive of the most lasting and important benefits. And though
it is true that the general form and policy of the Institution were determined
under the authority of Congress, by its first Board of Regents, yet it is quite as
certain that strenuous action was afterwards needed to maintain it in its adopted
‘course, and secure it from projected innovations which, though strenuously
advocated at the time, few now regard with aught but disfavor. T’o this end no
one lent more effectual aid than our lamented colleague. Although, from taste
and the conditions of his active life, he might more properly be styled a literary
man, yet were his scientific attainments by no means inconsiderable, and a liberal
and cultivated mind, which admitted of no narrow views, enabled him to em-
brace, in all its comprehensive simplicity, the idea of the generous foreigner
who, in founding this Institution, consecrated his fortune to ‘the increase and
diffusion of knowledge among men.”

In whatever Mr. Pearce engaged he exhibited the same spirit. Marked as a
leader from his boyhood, at school as at coliege, in his profession as in the
councils of the nation, in his neighborhood, hi: State, his country, as well as in
the church to which he had dedicated his faith, he stood distinguished for an
enlightened estimate and an efficient support of whatever is elevated and caleu-
lated to elevate. To him the work of construction was ever far more congenial
than that of demolition; to improve and preserve was an instinct, to confound
and destroy, an innate aversion of, his nature. Refined in his tastes, brilliant in
society, instructive from the affluence of his ideas and extent of information,
without ostentation as without pretension, social, genial, even playful among his
intimates—such was the associate whom we must long mourn, feeling that at
the council board as in the familiar and friendly circle, we have lost one who
strengthened us in our adhesion to what is right, good, or true, while ever prompt
to lead us wherever progress held out rational hopes of improvement.

Generally, men of the temperament we have described are impatient of details;
but this was not at all so with our departed friend. It afforded him pleasure to
systematize and reduce to order even the dry details of finance, and a wonderful
memory and a quick perception enabled him to pass them in rapid review with
a scrutiny of every particular. His mental vision was as minute as compre-
hensive, and his analytical faculty never dismissed a subject of investigation
until he was thoroughly satisfied with the arrangement, the method, the results :
in a word, he was content with little less than the perfection of whatever occu-

ied his attention or claimed his solicitde.

The objects which in Congress occupied most of his attention, and which it
gave him most pleasure to defend and sustain, were those connected with litera-
ture and science, and in these he showed the same qualities which as chairman
of our executive committce he has here so often exhibited. With the great
interests of state and the high objects of national politics he was abundantly quali-
fied to grapple; in fact, he shrunk from no occasion in which to exert himself when
enlarged views and skilful powers of debate could be rendered serviceable to his
country or the world. But if duty called upon him from time to time for such
efforts, still it was to objects promotive of art and science and high civilization,
to means for man’s moral and intellectual improvement, and for the enlargement
of his knowledge and power over nature, that he turned with ever new and un-
wearied interest. ‘To him probably more than to any other senator the library
of Congress was indebted for the augmented fund which it has now for some
years enjoyed, and for the care taken in the selection of the materials which
render its shelves so useful. The exploring expedition was more than once
indebted to his earnest and persistent efforts for the continuance of the means
of publication of its results; the Coast Survey for expositions of its importance
to the country and the world; the Smithsonian for warding oif assaults, and
reconciling enthusiastic but misguided opposition ; the naval and military expe-

102 EULOGY.

ditions, boundary surveys, and explorations, for close, searching investigations,
which led to important improvements and to cordial support. The great work
of the extension of the Capitol found in him a wise advocate and judicious friend.
Not afraid of what was new, he yet aimed at nothing for the sake of novelty.
In connexion with the decoration of our public buildings, our sculptors and
painters found in him a most enlightened appreciator of their works, and one
always ready to promote the great cause of their art by legitimate means.

He had a remarkable power of attaching to himself men of science, literature,
and art, and, in return, found in them some of his most intimate and highly-
prized companionships. His friendships were warin, and once formed, were
proof against all trials of absence or change of fortune. Many of his ardent
attachments reverted to the friends and associates of his parents, and to family
relations of even an older date, acquiring in his breast a sacred title by the
claims of the past.

The genial elements of his character naturally expanded most freely in the
circle of his family and friends, where he was truly and ever at home. His
garden, its fruits and flowers, were his habitual delight; his farm and its opera-
tions seemed to touch by association the springs of his deepest affections. He
superintended every process with a judgment rarely at fault, and watched all
the varied developments of nature with the interest of the amateur or the natur-
alist. Whoever had not seen Mr. Pearce in his dwelling, in his garden, or upon
his farms, knew him but imperfectly.

JAMES ALFRED Pearce, the colleague, the counsellor, the friend, to whom
we must now bid a final adieu, was born in the town of Alexandria, then part
of the District of Columbia, December 14, 1805. His parents, who were’ of
Scottish descent, and citizens of Maryland, dying during his childhood, the care
of his education devolved upon his maternal grandfather, the late Dr. Dick, of
Alexandria, an eminent physician of that day, who will be remembered by the
student of American history as having been one of the medical attendants who
ministered at the dying bed of Washington. So rapid yet thorough was the
progress of the young student in the rudimentary stages of education, that he
graduated at Princeton College at the boyish age of seventeen, bearing away
from competitors of no ordinary ability, and much subsequent distinction, the
highest honors of his class. Having adopted the law as his profession, and
permanently settled at Chestertown, Maryland, the former residence of his
parents, he soon reecived the earnest of future success in the confidence, affee-
tion, and support of the community—a community to whose favor he might,
indeed, already look forward in virtue of the memory of a meritorious and dis-
tinguished ancestry. His first step upon the more public stage which was
thenceforth to be the scene of his labors and success was his unsolicited election
to the legislature of Maryland, in 1831. From that day, with a single inter-
val of two years, his talents and time were devoted to the service of his fellow-
citizens in the halls of legislation, his career having led-him, by a progression
founded on the uncanvassed but ever-increasing confidence and respect of the
people, through the House of Representatives to the Senate chamber, in which
he was fulfillmg the unexpired term of a third election at the period of his
death.

His characteristic qualities and tendencies as a legislator have been already
slightly touched upon in this memorial, but whoever recalls the momentous
events. the gigantic and often acrimonious struggles for ascendency, the por-
tentous and brilliant debates which, from 1835 to 1861, fixed the public at-
tention, and excited the alternate hopes and fears of contending parties;
whoever pictures to himself the majestic forms which then occupied the legis-
lative arena, will remember that, through all these events, and measuring him-
self in no unequal competition with the foremost men of that earnest time,
our colleague continued to advance steadily in public appreciation, to fill a yet

EULOGY. 103

wider and wider space in the eyes of the country, that on him rests no imputa-
tion of having ever purchased favor or advancement by a sacrifice of the slightest
principle, or of having once deviated into any of those equivocal positions which
sometimes bring disrepute on illustrious names ; whoever shall recall and consider
these things will undoubtedly be qualified to form a more adequate and vivid
conception of his labors and his worth than could be derived from any por-
traiture which this occasion would permit, or perhaps even the most labored
eulogy could supply.

Nor were striking testimonials wanting to his peculiar and conspicuous merits :
it rested but with himself to have occupied positions of the highest publie dis-
tinction. A place in the cabinet and a seat in the federal judiciary were suc-
cessively offered him; on more than one occasion his name was publicly can-
vassed in connexion with the presidency of the United States. The former,
however, he declined ; the latter he steadily diseountenanced. He seems to have
felt that the Senate chamber was the proper sphere for his peculiar tastes and
powers—a sphere equal to his well-regulated ambition, not below his admitted
merit. The patronage incident to the executive branch of government involves
much that would have been repugnant to his feelings; the judiciary has objections
peculiar to itself in the ever-recurrent and monotonous. nature of its functions ;
the representative department of Congress was for him too much influenced by
the fluctuations of popular opinion. ‘The Senate, in the stability of its tenure,
and the vivacity and variety of its discussions, in its character of a consultative
and executive as well as legislative body, in the dignity and importance of its
deliberations, involving the interests of States and the relations of national inter-
course, seemed exactly fitted to give scope to his abilities, and to satisfy every
aspiration he might indulge for usefulness or consideration. Perhaps it was in
the committee-room that his influence made itself more particularly felt, for here
the extent of his information, the weight of his character, the directness and
integrity of his purpose, his patience for details, his familiarity with the forms
of business, and aptitude in applying them with logical acuteness to the disen-
tanglement of questions of fact and law, his co-operative spirit, his genial and
companionable nature and manner, all conspired to give authority to his decisions,
and to conciliate reliance and acquiescence on the part of those with whom he
acted.

Had Mr. Pearce not embraced the profession of law, he would doubtless, under
suitable circumstances, have been celebrated as an agriculturist. Had he not
resigned himself to political life, he could not have failed of eminence in science
or in literature. It is indeed rare to meet with one whose capabilities and excel-
lencies were so varied and so distinct, nor is it possible that, knowing him as I
have done, I should speak of him otherwise than frankly and from the heart,
though conscious of the imperfect representation which I have been able to give
of a man s0 intrinsically great in all the elements which constitute true greatness,
so entirely beloved for all that refers itself to the amenities of social intercourse
and the sacred endearments of home.

Tn conclusion, it is proper to add that the peculiarities which marked his char-
acter during the active years of his life exhibited themselves in the closing period
of his career under a new but harmonious aspect. Afflicted with an incurable
malady, he contemplated his approaching end and endured his intense suffer-
ing with the unwavering faith and resigned patience of a Christian. The reli-
gious principles which he had imbibed in childhood, and which had perhaps im-
perceptibly formed the basis of his character, became the dominant objects of his
thoughts, and the consolation and happiness of his last hours.

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GENERAL APPENDIX

TO THE

REPORT FOR 1862.

The object of this appendix is to illustrate the operations of the Institution
by the reports of lectures and extracts from correspondence, as well as to furnish
information of a character suited especially to the meteorological observers and

other persons interested in the promotion of knowledge.

LECTURES

ON THE

UNDULATORY THEORY O02 LIGHT,

Bey eH Ae BAUR IN AS RD esa Die tly,

LATE CHANCELLOR OF THE UNIVERSITY OF MISSISSIPPI.

[In preparing the material of these lectures for publication, some transpositions have
been made in the original order of topics, and the lecture form has been generally aban-
doned. “Mathematical illustrations have also been occasionally introduced, which would
not have been quite in place before a popular audience. |

PART I.
INTE OD UCT OR XN:
OUTLINE OF OPTICAL DISCOVERY.

The knowledge which we possess of the material objects surrounding us in
the universe is principally received through the sense of vision. Irom the
other senses we derive a much more limited range of impressions. 'The touch
furnishes us with a valuable means of confirming or correcting the information
we receive from sight; but its usefulness extends only to objects in our own
immediate vicinity. The hearing, though t hrough it, by the aid of spoken lan-
guage, we are supplied with a vast muiiarde of ideas which have had their
origin in impressions previously made upon other senses, contributes of itself,
in any other form, but very slightly to the great stock of our knowledge.

Such therefore being the pre-eminence of vision among the senses, light,
which is its medium, is, and has ever been, the most important of phy sical
instrumentalities in promoting the intellectual development of the human race,
and making progress a possibility. But, while occupying this peculiar relation
to the history of our advancement in the knowledge of nature, while so fertile
in the revelations it has unfolded to us of the properties and qualities of other
things, it is remarkable that light has itself furnished, in its own nature, one of
the most difficult and perplexing of all the subjects of physical inquiry; so
that, even down to an advanced period of the present century, the world of
science may be said to have been upon no other subject more widely at vari-
ance than upon the elementary and fundamental question, What is light?

Nor is it possible to explain this want of harmony by supposing the inquiry
to have but recently originated. Since, in the physical world, light has
been the ever present and ever most efficient handmaid of the human un-
derstanding, its phenomena must, to some extent at least, have attracted the
attention of the first intelligent inhabitants of our planet. The first man who
breathed could not have failed to notice the images of visible objects, formed
by reflection in the bosom of every quiet pool; and the first rude navigator

108 EARLY WRITERS ON OPTICS.

who endeavored to float himself from shore to shore, across waters too deep to
be traversed by ordinary and simpler expedients, must have been struck by the
singular distortion of his paddle at the line where it entered the water. The
natural alternations of light and darkness, their coincidence with the rising and
setting of the sun, the appearance and disappearance of the stars, the changes
of the moon, the rainbow in the clouds, the differences between different bodies
as luminous and non-luminous, transparent and opaque, and finally the very
fact of vision itself—all these phenomena constantly, from the earliest times,
presenting themselves without being sought, must have excited the curiosity of
men and invited investigation, centuries before the systematic study of nature,
in any of her varied departments, had had a beginning.

But the difficulties which perplex the inquiry m: uifest themselves in the im-
perfection of the speculations which have come down to us from the earliest
philosophers regarding the subject, and in the extremely slow progress of dis-
covery which marks much of the later history of this interesting branch of
science. A notion was for a very long time prevalent among the ancients that
vision is effected by means of rays procee ding from the eye to the object. This
idea is not found in Aristotle; but it was introduced into the schoo: of Plato,
and continued to be received for many centuries. The persistency of the doc-
trine is remarkable, inasmuch as the light which is self-evidently indispensable
to vision, proceeds from sources foreign to the observer.

The elementary phenomena of reflection and refraction suggest a natural
division of the science of optics into two branches; and this distinction is made
by the earliest systematic writer on the subject whose works have descended
to us. This was Euclid—supposed to have been the geometrician of that
name—who lived about 300 years before our era. The general laws which
govern the reflection of light, being comparatively easy of detection, were stated
by him with tolerable correctness; but what he has written on refraction is of
little value.

Ptolemy, the astronomer of Alexandria, who was born about the year 70 of

our era, attempted to discover the law of refraction by experiment. “His appa-
ratus was ingenious, and was not different in principle from that which has been
employed by Silbermann, Soleil, and others, in our own time, for the same pur-
pose. He measured the angles of refraction corresponding to various angles of
incidence, between 0° and 90°, for both water and glass, and left his measure-
ments recorded in his System of Optics. In order that we may judge of the
degree of accuracy attained by him it is necessary to anticipate what is to follow,
so far as to define, in this place, a few technical expressions. By the angle of
incidence made by light falling upon a reflecting or refracting para is
meant the angle between the ray and the perpendicular to the surface. By the
angle of refraction is meant the angle between the ray which has passed
through the surface and the same perpendicular on the other side. By the
angle of reflection is meant, in like manner, the angle between the reflected
ray and the perpendicular. By the plane of incidence, the plane of refraction,
or the plane of reflection is meant the plane which contains the incident ray
and the perpendicular, the refracted ray and the perpendicular, or the reflected
ray and the perpendicular. All these planes are coincident, except in cases
where double refraction takes place, when one of the planes of refraction is not
usually coincident with the corresponding plane of incidence.

As a measure of the amount of deviation or change of direction produced in
a ray by refraction, the sine of any given angle of incidence is divided by the
sine of the corres sponding angle of refraction, which latter is determined by ob-
servation. The quotient is constant for the same substance, no matter what be
the angle of incidence taken. It is called the cxdex of refraction. The con-
stancy ‘of this quotient was not known to Ptolemy. The discovery of its con-

SNELLIUS —LAW OF REFRACTION. 109

stancy, at a comparatively recent period, marks an era in the history of the
science ; and it was, as we shall see, the discovery of the /aw of refraction.

The ascertained index of refraction for water is 1.33582. If we make a com-
putation of its value from the measured angles of Ptolemy, we find a mean of
1.30147. Butif we take his measurements at the incidence of 50°, where the
relative variations of the angles of incidence and refraction are most marked and
most easily measured, we obtain 1.33555, which is exccedingly near the truth.

The true index of refraction for glass is between 1.48 and 1.60, according to
the materials and density. Crown glass varies from below 1.50 to about 1.525.
Ptolemy’s mean determination would be 1.484. But at 50° he approaches
nearer the truth, his angles giving 1.5321.

For rays passing from water to glass, the relative index computed from his
measurements would be 1.1390, the true being 1.14145. ‘The near agreement
of these numbers with modern determinations is remarkable, especially consid-
ering that Ptolemy’s measures are given only to the nearest half degree.

Ptolemy was unable, however, to derive any practical advantage from these
results, since the magnitudes of the angles seemed to be governed by no law
which he could detect. And in this unsatisfactory condition the whole subject
of refraction remained for the fifteen succeeding centuries.

As an astronomer, Ptolemy could hardly fail to notice the effect of atmos-
pheric refraction upon the apparent positions of the heavenly bodies; and he
has the merit of having recognized the fact, which others after him disputed,
that the displacement is always in a vertical plane, and also that it attains its
maximum in the horizon and is zero in the zenith.

About half a century later than Ptolemy flourished Claudius Galen, the cele-
brated Greek physician. Ina treatise on the uses of the members of the human
body he speaks at some length of the phenomena of vision, and lays down the
fundamental law on which the stereoscope has been very recently constructed,
that the picture which we sce of a solid body is made up of two pictures dis-
similar to each other, one seen by each eye separately.

But it was impossible that optical science should make any important pro-
gress so long as the law which determines the path of a ray in passing from one
medium to another remained unknown. We are compelled, therefore, to descend
to the earlier portion of the 17th century before we find a practicable ground on
which to build a systematic science, or lay even a foundation for the splendid
superstructure which the future had in reserve in this department of physical
inquiry. In the year 1626 Willebrord Snellius, professor of mathematics at
Leyden, died at an carly age, leaving behind him manuscripts, among which was
contained a statement of the important law in question under the following form:
If MN be a plane horizontal surface, dividing a denser
medium below it from a rarer one above, and if a point at D
be observed by the eye at A, the apparent place of D will be
at B, vertically above D, in the line AC produced ; and what-
ever be the inclination of the ray to the surface, the line CD

Fig. 1. will be to the line CB in a constant ratio. Or, if CD be made
the radius of the circular are FDQ, and DE be drawn perpendicular ‘to the
surface, the radius CI, being the visual ray AC produced, will be divided at B
in a constant ratio. If, at ', we draw to the circle the tangent FH, producing
CD and CB to mect it at H and G, then CH and CG, which have the same
ratio to each other as CD and CB, will be the secants of the angles HCI
and GCF, or the co-secants of the angles HCQ and GCQ, (—ACP,) formed
by the refracted and incident rays with the perpendicular, PQ, to the refract-
ing surface MN, technically called the angles of refraction and of incidence.
The geometrical law of Snellius, therefore, translated into the language of
trigonometry, is this: That when a ray, passing from one medium to another,
undergoes refraction at the common surface, the ratio of the co-secant of the

110 EFFECTS OF REFRACTION.

angle of incidence to the co-secant of the angle of refraction is constant. As
the co-secants of angles are inversely as the sines of the same angles, the law
may be more conveniently expressed by saying that, in the circumstances sup-
posed, the s¢mes of the angles mentioned are in a constant ratio. It was in this
form that the law was first published by Descartes, eleven years after the death
of Snellius. It is, therefore, frequently referred to as the law of Descartes.

It may be proper to mention that, previously to the discovery of this impor-
tant law by Snellius, it had been remarked by the illustrious Kepler that for
incidences below thirty degrees a ratio almost constant exists between the angles
of incidence and of refraction themselves. _ This is true because for small angles
the increments of the are and of the sine are nearly proportional. But when the
incidence is moderately large, the divergency of the two ratios becomes very
wide,

An examination of the figure given above will show that the refraction of a
plane surface produces no distortion in lines which are at right angles to the
surface, but only diminishes or increases their apparent length according as the
medium in which the object is situated is denser or rarer than that on the side
of the observer. Thus the line ED is reduced to the apparent length EB.
The amount of this reduction increases with the obliquity of the visual ray, for
the ratio of CD to CB, which is constant, is always less (except when the
incidence is perpendicular) than the ratio of ED to EB, and the divergency
of these ratios is always increasing. It follows that the apparent depth of a
fluid is always less than the real depth, and that the illusion.is more striking in
proportion as the point observed is more remote from that immediately beneath
the eye. Thus the horizontal bottom of a cistern or pool of uniform depth
presents a curved appearance like
that here represented. If MN be

N the surface and ICL the horizontal
Ww plane at the bottom of a sheet of
L water, the eye being placed at the

point P above it, this plane will
present a conchoidal appearance
like that of the curve D’E’’A”,
The position of the points of the
bottom which, to an eye situated at P, appear in the directions PD, PE, &c,
may be found by asimple geometrical construction. Drawing the perpendicular
PAA’, divide the depth AA’ at the point A’, so that AA’ shall be to AA”
in the ratio of 2 to 1:—mn being the index of refraction. Through A’ draw
VW parallel to the surface. Produce PD, PE, &c., until they intersect the
bottom at G and H, and with the radii DE and EH describe the circular ares
GG’ and HH’. Through G” and H” where DG, EH, intersect VW, draw per-
pendiculars to the bottom, intersecting the ares in G’ and H’, Join DG’ and
EH’. The points D’ and E’, where the joining lines intersect the bottom, are
the points which will be seen from P in the directions PD, PE, and the ap-
yarent positions of those points will be at D” and E”, where the visual rays
PD and PE produced meet perpendiculars drawn from D’, EY’, to the surface.
Any number of points being thus found, the curve drawn through them all
will show the appearance of the level bottom M/N‘ as it is seen from a point
above the surface as P. This curve is a conchoid, whose polar equation is
—psecy + # seeg’ ; HE Pe ee
Cpt Ein G1 Rt ieee aap ae nee eI
in which pis put for PA, qg for AA’, » for the index of refraction, g for the
angle EPA, and ¢' for EE’E”.
.It is apparent from the foregoing that all lines seen through a single plane
refracting surface, unless they are perpendicular to the surface itself, are more

UNEQUAL REFRANGIBILITY OF DIFFERENT COLORS sie la

or less distorted. A straight rod partly immersed in water, as FD‘, appears
sharply bent at the surface, and slightly curved beneath, assuming the apparent
direction OD”. Moreover, though, as in this case, the real direction should
pass through the eye, so that in a uniform medium, only the extremity could be
visible, the effect of refraction gives a lateral view of all the part immersed.

The next important step in the progress of optical discovery, after the detec-
tion of the general law of refraction, was made by the illustrious Newton, who,
in the year 1672, communicated to the Royal Society the experimental researches
by which he established the compound nature of light, and the unequal refran-
gibility of its component rays. He held that the common white light of the
sun is made up of elementary rays differing at the same time in color and in
refrangibility. The number of tints which he considered sufficiently distinct
to be regarded as independent components is seven. It seems unnecessary,
however, to suppose the existence of: more than three elementary colors, it being
possible, by mingling these in various proportions, to produce all the rest, while
the degrees of refrangibility between the extreme limits vary through an infi-
nite number of infinitely small differences.

Newton’s method of demonstrating the truth of his doctrine was as simple
as it is ingenious. The colors which border the images of objects observed
through prisms of glass or other transparent substances, or through cylindrical
or globular vessels filled with water, had long been familiar. Newton placed
such a prism in the path of a ray of the sun’s light, introduced through a small
aperture into a dark room, and received the refracted image or spectrum upon a
white screen placed at some distance. Before the interposition of the prism
the beam produced upon the screen a white and circular image of the sun itself.
But after the rays had been bent by refraction the image appeared very much
elongated in the direction of the refraction, and brilliantly colored in a series of
tints, passing by insensible gradations from red, through orange, yellow, green,
blue, and indigo to violet. 'This last color was at the end most refracted. In
turning the prism around an axis parallel to its edges, Newton observed that
the deviation of the spectrum from the original direction of the sun’s rays was
variable, increasing from a certain minimum (experimentally found) by turning
the prism either to the right or to the left. This minimum corresponds to that
particular position of the prism at which the angles of incidence and emergence
are equal. Upon this observation he founded a test experiment in regard to the
refrangibility of the rays of different colors. Making a small circular aperture
in the screen upon which the spectrum was formed, at a point where, by turn-
ing the prism, he could pass the entire spectrum over it, he placed behind the
aperture a second prism, which thus reccived, successively, rays of a single
color only. At a distance behind the second prism a second screen intercepted
the light which passed through it, when it was observed that this second image,
instead of being elongated like the first, remained sensibly circular, while the
positions of the circles of different colors upon the screen were further and
further removed from the original direction of the unrefracted rays as the tints
ascended from red to violet. ‘This phenomenon of the separation of the compo-
nent- colors of light by refraction has been called dispersion. Newton was of
opinion that the dispersive powers of all bodies are equal; or, in other words,
proportional to their refractive powers; and that, the mean refractive powers of
two bodies being equal, their refractive powers for each particular color must be
equal also. Both these suppositions, as we shall see, are unfounded.

The discovery of Newton furnished an easy explanation of the interesting
natural phenomenon of the rainbow. ‘This beautiful meteor had been the sub-
ject of many unsatisfactory speculations; and though de Dominis, as early as
1611, had furnished a true theory of the manner of formation of the inner bow,
he had not been able to account for its colors. He showed that there is a certain
incidence at which, if the parallel rays of the sun fall upon the anterior surface

‘

112 THE RAINBOW.

of a transparent globe, they will be reflected from within so as to emerge, still
parallel to each other, at a point on the other side of the centre. The emergent
rays will form a constant angle with the incident rays, and, entering the « eye
of the observer standing with his back to the sun, will form the same angle with
a line supposed to be drawn from the sun through the eye. This line from the
sun through the eye being made an axis, and the above supposed reflected ray
being revolved around it, there will be traced out in the heavens a circle, from
every part of which, if rain-drops are present, there will come an amount of
light above that which is reflected from the surrounding cloud.

This explanation satisfactorily determines the locus of the bow; but it fails
to account for its tints, or the extent of surface over which they are spread. It
would require that the are should be white, and that it should be no broader
than the sun; that is to say, that its breadth should be only about half a degree.
The actual breadth of the inner bow is, however, two degrees and a quarter;
and that of the outer three degrees and three quarters. Newton’s discovery
furnished the necessary supplement to the theory.

In fact, if the circumference PP’/P” be a section
through the centre of a transparent globe, and IP a
ray of the sun falling on it in this plane, it is easy to
see that this ray, or portions of it; will undergo many
reflections within the globe, while portions will succes-
sively emerge at the points in which reflection takes
place. “E here will first be some loss by external reflec-
tion in the direction PR. The portion which enters
the globe will be bent, by refraction, from the original
direction PIs to the direction PP’. At P’ a portion
will emerge in the direction Pt, being bent from the
direction PQ as much as PP’ was bent from PK.
The same thing occurs at P’, P’’, and so on. Put ¢ = the angle of incidence
(the angle made by the incident ray with the radius)—the angles of emer-
gence are all of this same value. Put p for the angle of refraction. The figure
shows that add the angles of internal reflection have this value. Let 6 represent
the bending or deviation of the ray by refraction at each incidence or emer-
eence., hen d—=:—p. And the amount of deflection of the successive re-
flected rays from the original direction being sige by D Die),
aud that of the successiv ely emergent rays s by A, 4’....D(™), we shall have
(an entire circumference being denoted by 27)

Deflection of PP’—d; deflection of PE—d—20.

Deflection of P’P"—D—d+7—2p; deflection of P’E’—=4’—20-+7—2p.

Deflection of P’ P’“—D/—0-+ 2z—4p; deflection of P’’E=4"—=20 + 22—4p.

Deflection preceding mth emergence—D(™)—0+m(z—2p); deflection mth
emergence— A(™)—20+ m(z—2p).

If, for 0, we put its value — :—p, we shall have—~

A'—=2:-+n7—4p. =
A" = 20+ 27—6op.
A(™)==2¢-+mz—2(m-+1)p.

The law of the formation of these eTon essions is obvious. The deflection
of each of the successively emergent rays is increased at each reflection within
the globe by the angular amount z—2p.

Now, as all these values contain the angle ¢, it is obvious that the deflections
cannot be equal when the incidences are uncqual; or, in other words, that the
emergent rays will usually diverge from each other. Moreover, the deflections
do not regularly increase and diminish with the incidence.

Putting the Dna A'—180°2, and 4/’—=360°.

Putting —662uand) ZM——24'S

Putting the een 70°, Al == 390 and A200 °°

nearly, for water.

' ’ THE RAINBOW. 113

Neither of the last values is intermediate between the two preceding in the
same column. In both cases, therefore, there appears to be some point between
the extreme incidences, where the deflection is a minimum; and it being the
law of maxima and minima that variations in their vicinity are insensible, it
follows that near the incidences corresponding to those values the emergent rays
will be sensibly parallel. But when the general expression—

A(™ )==2'-+- mnz—2'm-+-1)e
becomes a minimum*, the cosine of the incidence must have the value—
cos ex + / fee is
V (m+1)?—1,
in which » denotes the index of refraction.

This determines, therefore, the incidences at which the deflections are minima;
and hence, those at which the emergent rays are (to use the term employed by
Newton) efficacious. It will be seen that, when the index of refraction is given,
the value of cos: will be affected only by the variable m, which is the number
of internal reflections. If this be made zero, cos: will be infinite; in other
words, when the rays are not reflected at all, they do not emerge efficacious.

By putting m—1 and m—2 we shall obtain values corresponding to the de-
flections which produce what are ealled the inner and outer bows. J'rom these
values we may deduce the apparent diameters of the ares; and the theoretic
results thus obtained are found to accord with actual measurements. By putting
m=3, 4,5, &e., successively, we may obtain the /oct of an infinite number of
additional bows; but after the second reflection, the light ceases to be intense
enough to produce an impression on the eye.

Since, with a very slight alteration of ¢ the rays cease to be efficacious, it is
evident that, if the sun were but a point, and the index x invariable, the bow
would be reduced to a simple line of light. But as every point of the sun will
produce its separate bow, the visible breadth, with » constant, would be that
of the sun itself—that is, about half a degree. Newton’s experiments on dis-
persion, however, showed that the value of the index » sufficiently varies, in
passing from the red to the violet, to alter sensibly the angle of incidence cor-
responding to the efficacious rays of the several colors, and sufficient, accord-
ingly, to alter the amount of deflection which those several rays undergo before
reaching the eye. As the bows appear in the direction of these deflected rays,
it follows that the different colors will not be superposed, and that the breadth
of the compound bow will be greater than the breadth of the sun by the total
amount of their want of conformity. The index for the red may be taken at
1.346; that for the violet at 1.333. Employing these values, we have for the
bow by one reflection:

Violet rays. -t, == 58° 40’. 4’, == 139° 43’. Radius of bow —=.40° 17’.

Red rays. - . -¢; = 59° 234’. 4', = 137° 584’. Radius of bow = 42° 12’.

* The general expression for the deflection being— ol
AV?) =21-++ma—(m-+1)p,
its differential is dA(™)=2de—2(m-+1 dp; which, when A(™) is a minimum, is equal to zero.

dé
From this we obtain the ratio, inet.
P

From the Snellian law, sinv—=nsinp, » being the index of refraction. This furnishes an-
another value of the same ratio, smce coscdi—=ncospdp.
di ncosp oh
Or, — = —=m-+-1; and (m+1)cost=ncosp.
dp cose

Squaring this, and adding to it 1—cos*:==n"sin’p, member for member, we obtain—
[ (aw-+-1)?—1 ] cos*z-+-1—=n*\ cos*p--sin*p)—=n?,
T'rom which we deduce the result in the text—

1?—-]

a
8s coy pF

114 DIFFRACTION—-DOUBLE REFRACTION.

And for the bow by two reflections: ‘
Violet rays.ty—= 71° 49/55". 4”, = 230° 58’ 50. Radius of bow 50° 58’ 50":
Red rays. . -¢ == 71° 26/10". 4”; == 234° 9/20. Radius of bow 54° 9! 20"

From the values of 4 it will be manifest that the rays which produce the
bow by one reflection must enter the rain drops above the ray which passes
through the centre; and that those which produce the bow by two reflections
must enter below the same central ray.

The differences between the values of 4, and 4, above, show the amount by
which the breadths of the bows are increased in consequence of the variability
of n. These amounts are, for the first bow, 1° 44’ 40’, and for the second,
3° 10 30’. The colors are produced by the want of conformity of the bows
corresponding to the several elementary rays; and their feebleness is owing to
the fact that, notwithstanding this want of conformity, they do, on account of
the considerable diameter of the sun, very sensibly overlap, while they are
also diluted by the white light reflected from the anterior surface of the drops.
Were they entirely superposed upon each other the bow would be white.

While the discoveries of Newton and Snellius, just mentioned, were: removing
old impediments to progress in optical science, observation continued to add
new ones more perplexing than those which had disappeared. In the year
1665 there was published, at Bologna, a posthumous work by Francis Maria
Grimaldi, an Italian Jesuit, in which were, for the first time, described certain
phenomena now very familiar under the name of diffraction. He stated that
if any very small object be placed in a pencil of divergent light,admitted through
a minute aperture into a dark room, its shadow will appear materially larger
than it ought if light passes its edges in straight lines; and, moreover, that any
opaque object, large or small, exhibits along the edges of its shadow a border
of at least three distinctly tinted fringes, the brightest and broadest of which is
next the shadow. He also observed that when two minute pencils of light are
admitted through apertures very near to each other, the sereen on which the
blended pencils fall, and which, as he supposed, ought to be uniformly illu-
minated with a light equal to the sum of the two intensities, is streaked with lines
absolutely dark. He was led by this observation to announce the paradoxicat
proposition that there are circumstances in which the union of two rays of light
produces darkness. Bold as this announcement must have originally appeared,
the progress of scientific discovery has fully confirmed its truth. ‘This phenom-
enon, being attributed to the bending of the rays of light in the immediate
vicinity of the opaque body, was distinguished by the name inflection or diffrac-
tion. It was carefully studied by Newton and others, and has occupied a prom-
inent place in ali the discussions which have since arisen in regard to the nature
of light.

Not far from the time of the discovery of Grimaldi, just mentioned, the atten-
tion of the scientific world was calied to a case of new and extraordinary refrae-
tion observed to take place in crystals of carbonate of lime—a species of retrac-
tion, which, from the circumstance of its dividmg an imcident beam into two
beams entirely distinct, or of presenting two images of any object seen through the
erystal, has been called double refraction. ‘The first publication on this subject
was made by Erasmus Bartholinus, a physician of Copenhagea, who gave to
the mineral the name of Iceland spar, from the circumstance that his specimens
had been obtained from that island. Jt is now known that this property of
double refraction is exceedingly common, being possessed by most crystallized
bodies, and capabie of beg produced, transiently or permanently, in any trans-
parent solid whatever, whether organic or mineral, in which it does not naturally
exist. It is only in Iceland spar, however, that it manifests itself in a degree
remarkable enough to attract the attention of a casual observer, and in most
cases li can only be detected by special arrangements.

DOUBLE REFRACTION. HED

Iceland spar is favorable to observations upon double refraction, not only on
account of its wide separation of the refracted rays, but also because of the size
of the crystals which can be obtained of this mineral, and of their beautiful
transparency. Its primitive crystalline form is the rhombohedron. Whatever
may be the configuration of the mass as obtained from its native bed, it will be
found to cleave with great facility in directions parallel to the faces of the
original rhombohedron, and it is thus easily reduced to a form favorable for ex-
periment. The angles of the rhomboidal faces are 101° 55’ and 78° 5’. The

z inclinations of the faces upon each other are 105° 5! and.
74° 55’. Two of the solid angles are contained by-three
of the obtuse angles of the rhomboids, and the other six
by two acute and one obtuse each. “The diagonal con-
necting the two exceptional solid angles is the shortest

Fig. 4. of the diagonals of the rhombohedron, and is called the
crystallographic axis. ‘These angles themselves are called the vertical, and the
other six the lateral, angles of the crystal.

If a mark be made with ink upon a sheet of white paper—a small cross for
example—and a rhomboid of Iceland spar, two or three inches in thickness, be
laid over it, then in whatever position the eye may be placed above the upper
surface of the crystal, two crosses will be seen. If the erystal be turned about
upon its horizontal face, one of these images will remain motionless, and the
other will describe a circle around it. The motionless image will, moreover,
appear sensibly nearer to the eye than the other. If, instead of a small mark,
we take a straight line ruled entirely across the paper as an object, then, if the
eye be placed vertically over the line, and the erystal interposed, it will be seen
that the nearer image is always a continuation of the part of whe line seen
beyond the erystal on each side, while the more distant one is more or less dis-
placed laterally. In revolving the crystal, moreover, this second image will
pass from one side to the other of the first, and.a position will be found (or
rather two positions, differing from each other by 180°) ia which the two images
apparently coincide, though, as they are differently distant, they are merely
superposed.

Until the discovery of this remarkable property in Iceland spar, refraction
was supposed to be governed in all cases by the law of Snellius. But it is im-
possible that this should be true of both the rays in the present case. It is, in
fact, true only of that one which produces the nearer and fixed image. This is,
for distinction, called the ordinary ray ; the other, the extraordinary.

If the vertical angles of the rhombohedron he truncated perpendicularly to
the crystallographic axis, and the artificial faces thus formed polished, it will be
found that when the crystal is laid over a small object upon one of’ these faces,
and the eye placed immediately over it, only one image will be visible. This is
not an illusion occasioned by the superposition of images differentiy distant ;
there is actually but oneimage. But if the emergeut ray coming tv the eye, by
which the object is seen, be at all inclined to the surface, the image will be
duplicated, and the degree of separation of the two images will increase with
the inclination. If the lateral edges of the crystal are cui away, so as to form
a parallelopipedon, whose faces are parailel to the erystaliographic axis, and the
crystal be laid on its side, the separation of the images will be at its maximum.
In this case, if the emergent visual ray be perpendicular to the surface, the tw
images will be superposed, but the duplicity will be very perceptible.

It appears, then, that there is one directiou in the erystal, in which light may
pass without double refraction, and tha. this direction corresponds with that of
the erystallographic axis. This direction is also called the eptic axis; but the
term optic axis, it must be observed, is not intended to denote a particular Line,
but only a particular direction, and in the present case it is a line anywhere in
the crystal parallel to the axis of symmetry.

116 DOUBLE REFRACTION.

Any plane parallel to the axis of ‘the crystal necessarily coincides with the
optic axis, and every such plane is called a principal plane or principal section.
This term is one of very convenient use. Any plane at right angles to the optic
axis (and therefore to allthe principal planes) may be called a conjugate plane or
section, which term will be also found to have its convenience. In every such
conjugate plane the separation of the two rays by double refraction is at its
maximum; and, what is also important, the extraordinary ray, as well as the
ordinary, obeys in this plane the law of Snellius. ‘The indexes of refraction for
the two are, however, necessarily different; that of the ordinary ray being
1.6543, and that of the extraordinary, 1.4833. In directions which do not
correspond with either a principal or a conjugate plane, the index of refrac-
tion of the ordinary ray will be found to be invariably the same, but that of
the extraordinary ray will gradually increase from the direction perpendicular
to the axis to that which coincides with the axis. In this last case the two in-
dexes become equal, and double refraction disappears. The index of the ex-
traordinary ray at any inclination (denoted by @) with the optic axis, may be
found from the following formula, in which x= 1.6543, n’—1.4833, and N is
the index sought:

N=V 22 —(n?—n?) sin2a= V 2.7367 — 0.5365 sina.

We see now why it is that one of the images seen through the crystal is
apparently nearer than the other. ‘The general effect of refraction by a single
plane surtace of a body denser than air, is, as has been already illustrated, to
bring the object apparently nearer to the surface. This effect must depend for
its degree upon the refracting power, and this power is a direct function of the
index of refraction. ‘The indexes of the two rays are different, and therefore
the apparent distances of their images are different likewise.

One of the most remarkable facts connected with the refraction of the ex-
traordinary ray is that, unless the incidence is in the plane of a principal section,
or of a conjugate section, the refracted ray is not in the plane of incidence. And
if the refracting surface, whether the natural surface of the erystal or one artifi-
cially prepared, be not coincident with a principal or a conjugate plane, the
extraordinary ray is bent at the surface, even when the incidence is perpendicular.

In observing through the crystal prepared by truncating its vertices by
conjugate planes. in which case we have the advantage of having both refracted
rays in all positions in the plane of incidence, we shall see that the extraordinary
ray is always the most distant from the normal to the surface. But this normal
represents the direction of the optic axis. ‘The extraordinary ray, therefore,
has the semblance of being repelled from this axis. As there are crystals in
which the’ apparent effects are reversed, that is, in which the extraordinary ray
is nearer to the optic axis than the ordinary. as if it were attracted, these two
classes have been distinguished by the terms negative and positive. In the
negative the extraordinary index is less than the ordinary; in the positive.
greater.

A curious observation in regard to the paths of the two rays through a erystal
of Iceland spar, by which an object at a litle distance beyond it is scen, origi-
nally made by Monge, may be mentioned here. The object
being at O, and the eye being at E, the ordinary image
will appear above the extraordinary and nearer, as at O’,
O” being the extraordinary image. The emergent rays
are therefore P/E and Q'E. But the rays incident on the
under side of the crystal from the object must be resp-c-
tively parallel to these. Draw then OP parallel to P’E,

Fig. 5. and OQ parallel to Q’E, and join PP’, QQ’. The en-

' tire path of the ordinary ray is then OPP'E, and that of

the extraordinary is OQQ’E, which lines, when the plane of incidence is a
principal plane, necessarily cross each other in the crystal.

DOUBLE REFRACTION. eT

If a card be passed along the under surface of the crystal, in the direction
RR, it will cut off the ray OP before interfering with OQ. The image 0’,
which is most distant from the card, is therefore first to disappear—a phenome-
non very striking when seen for the first time. The card employed in this
experiment should be dull black in order to produce the best etiect, otherwise it
is too conspicuous itself.

When a ray of light, after having passed through one crystal and having been
divided into two distinct emergent rays, is allowed to fall upon another similar
and equal crystal similarly situated, the effect, as might naturally be expected,
will be to increase the separation of the rays to the same extent as would have
occurred had both the crystals been united in one. But if the second erystal
be turned around the direction of the ray as an axis, other phenomena make
their appearance, the character of which depends on the amount of turning. In
speaking of this kind of revolution it will be convenient to employ the term
azimuth. By this word is meant direction in space in a plane at right angles
to any axial line. ‘Che term is adopted from astronomy and geodesy, in which
sciences the assumed axial line is the vertical, and the azimuthal plane the
horizon.

In the case in hand, if we completely reverse the position of the second
crystal in azimuth, that is to say, turn it round 180°, it will reverse the refract-
ing effect of the first crystal and reunite the two rays, which will emerge as
one. If we turn it only 90° in azimuth the separation of the rays will con-
tinue, but that which was the extraordinary ray in the first crystal will become
the ordinary in the second, and vice versa. Accordingly, if the original inci-
dence is perpendicular, the ray which follows the normal in the first erystal will
be bent at the surface of the second, and that which is bent at the surface of the
first will follow the normal on entering the second.

At any azimuth differing from the original position more or less than 90° or
180° there will be seen four emergent rays, of which two will usually possess
a greater intensity than the other two. When the change of position of the
second crystal is but slight, the two original rays will be vivid; but, in a linea
right angles to that which connects them, two very faint ones will appear, nearer
together than the original two. As the rotation advances these new rays will
gain in strength, while the other two grow less intense. At the azimuth of 45°
the four will be equal and equidistant. Beyond 45° the original rays go on
fading and the new ones increasing in brightness, until, at 90°, the former become
entirely extinct and the new ones remain alone. Beyond 90° again another
faint pair appear, which go on, as before, increasing in brightness, at the expense
of the companion pair, up to the azimuth 135°, when the four are again equal.
Beyond 135° this second new pair still continue to gain strength and to approach
each other, till, at the azimuth 1809, they reunite into one, and the others in their
turn vanish. In the figure following, these successive phases are shown as
they appear upon a screen when the experiment is performed in a dark room.
‘They are circumscribed by the outlines of the two rhombs in their relative sue-
cessive positions.

a

yA
@
°@

The phenomena of double refraction were carefully studied by the celebrated
Huyghens, who devised a physical theory for their explanation, which has been
pronounced by Brewster to be one of the most splendid of the triumphs of genius
which illustrate the history of science. His theory did not, however, extend ta
the explanation of the remarkable appearances last described, which present

118 COLORS OF THIN PLATES.

themselves when two doubly refracting rhombs are combined—appearances
which were observed by him with surprise and perplexity. They are now
known to be owing to a remarkable modification of light which always accom-
panies double refraction, though it may be produced in other ways, and which
is called polarization. 'This will oceupy much of our attention further on.

Soon after his announcement of the compound nature of light, Sir Isaac
Newton made public the results of his ingenious investigations in regard to the
colors exhibited by then plates of transparent substances, such as soap-bubbles,
films of moisture upon glass and upon polished opaque solids, laminz of air
confined in fissures of transparent minerals, &c. He showed that the tints dis-
played by such thin plates, when viewed in common light, depend upon three
conditions, viz: the thickness of the plate, its refracting power, and the angle
of obliquity under which it is viewed. 'The determination of the relation of the
tint to the thickness, was made by means of a very simple contrivance. A
double-convex lens, of very long focus, was placed in contact with the plane
surface of a plano-convex lens, the two being pressed together by means of
screws. In Newton’s experiments the double-convex lens was beneath and the
plano-convex above. ‘The convexity of the upper surface of the upper lens is
advantageous when oblique observations are desired, as tending to reduce the
refraction of the incident and emergent rays at that surface. The two touching
surfaces have, theoretically, but a single point of contact, and that point is the
centre of a thin plate of included air, of which the thick-
ness increases from zero equally in all directions. The
law of this increase will be apparent from the figure
annexed. MN represents the lower surface of the supe-
rior glass, and QR the upper surface of the inferior. Let
C be the centre of the sphere of which QR is a super-
ficial section. Put 7 for the radius CP. Then, if the
ares Pa, P), are small in proportion to the whole circum-
ference, we shall have

2 7

“

/ / os
Piel Ag Sind PR pe
2r 2r

Or, if 2 stand generally for the thickness Aad or Bé,and y for the corres-
ponding distance from the point of contact, PA or PB, we shall have the vari-
ation, recy”.

This furnishes a law by which, when the thickness corresponding to a single
assigned value of y is known, the thickness for all other values may be com-
puted with great facility.

The apparatus being arranged as above described, the colors which are seen
by reflected light are arranged in regular rings around a black centre and in suc-
cessive series, as follows:

Black, blue, white, yellow, red.

Violet, blue, green, yellow, red.

Purple, blue, green, yellow, red.
Green, red.

Greenish blue, red.

Greenish blue, pale red.

. Greenish blue, reddish white.

These are what Newton calls the successive orders of colors, and, in referring
lo any particular tint, it is designated as the blue, red, green, &c., of the first,
second, or third order, as the case may be. Beyond the fourth order the colors
become feeble or begin to fade rapidly out into whiteness, and, beyond the
seventh, color can scarcely be at all perceived. he cause of this fading may
be made manifest by employing homogeneous or monochromatic light; that is
to say, light of a single tint only, obtained by isolating a portion of the rays of

ee

COLORS OF THIN PLATES. 119

the prismatic spectrum whose refrangibility and color are sensibly the same.
Then very many more bright rings will be observed, separated by intermediate
rings entirely dark. But what is of most importance at present is that those
which are formed by the least refrangible rays are larger than any others, and
that the diameters of rings of the same order regularly diminish as the refran-
gibility increases. ‘This difference of magnitude between the rings of different
tints occasions the overlapping of one color upon another when white light is
used, so that the colors observed are not simple but resultant colors, determined
in their tints by the simple colors which happen to be predominant at any point.
The other components serve, with some portion of the predominant tint, to pro-
duce white light, by which the tint is diluted and rendered more feeble than it
would otherwise be. The truth of this explanation will be made apparent by
viewing the rings through a prism. The effect will be to make the overlap-
ping on one side more complete than before, and, on the other side, less. The
rings will be less highly colored but more numerous and better separated on the
side of greatest refraction, and more confused on the other.

From a careful measurement of the diameters of all the bright rings, Sir
Isaac Newton ascertamed that the squares of these diameters form a regular
arithmetical progression, corresponding to the natural series of odd numbers, 1,
3, 5, 7, &e. And the squares of the diameters of the intermediate dark rings
were found to constitute another similar progression, corresponding to the series
of even numbers, 2, 4, 6, &c. From the law aay’, it therefore follows that
the bright rings appear where the thickness of the plate is once, thrice, five times,
&c., some constant value, and that the dark rings appear where the thickness is
twice, four times, siz times, &e., the same constant value. The next question
to be determined is, therefore, what is that constant?

In order to ascertain this, Sir Isaac Newton measured with great precision
the absolute diameter of the fifth dark ring. This, with the known radius of the
spherical surface of the lens, enabled him to compute the thickness of the plate
at that ring, this thickness being the versed sine in a great circle of the sphere
of an are of which the measured diameter is the chord. The result gave him
e000 Of an inch, very nearly, for the thickuess of the plate at the fifth dark
ring. But the fifth number in the series 2, 4, 6, &c., is 10. Hence, the con-
stant sought for is one-tenth of s5255 of an inch, or ;7),5), and this is the
thickness of the plate at the point where the greatest brightness of the first
bright ring is seen. Reduced to a decimal, it gives a little more than fifty-six
ten-millionths of an inch. If the value of this constant be sought for the several
homogencous rays, it will be found to be, for the violet, a little more than thirty-
nine ten-millionths, and, for the red, not quite sixty-nine ten-millionths. As, in
the space occupied by the colors of the first order, the thicknesses vary slowly,
and as there is a certain range of variation in thickness within which each color
may appear, though its greatest intensity is in the middle of this range, it
happens that the colors of the first order are dilute, especially toward the centre
of the system, and that the middle of the series is white. In the succeeding
orders, the differences tell in such a manner that the bright rings of some colors
fall more or less exactly upon the dark rings of others, and the tints become
stronger. But, as the thicknesses soon begin to vary rapidly, every system of
rings becomes crowded, and the separating dark intervals grow narrower and
narrower, until there is a complete blending of tints at every point and the
resultant is sensibly white. When water is introduced between the glasses, the
rings become immediately smaller. If the thickness at which a given tint now
appears is compared with that at which the same tint appeared in air, it is found
to be reduced in the ratio of ” to 1, 2 being the index of refraction between air
and water. This law admits of being generalized. In fact, whatever be the
substance of the thin plates in which these tints appear, the thicknesses which
produce them are inversely proportional to their indexes of refraction.

120 COLORS OF THICK PLATES.

When the system of lenses described above is held between the eye and the
light, another system of rings makes its appearance, which is formed by the
transmitted light. In this case the tints are much feebler, being diluted by the
intermixture of a great deal of white light, which, as we shall see hereafter, has
nothing to do with their formation. Of these it is remarkable that the diame-
ters of the bright rings correspond with those of the dark rings seen by reflec-
tion. Thus the thicknesses at which the bright rings by transmitted light
appear form a series corresponding with the progression of even numbers, 0, 2,
4, 6, &c.; and the thicknesses at which the intervening dark rings are scen cor-

- respond to the progression 1, 3, 5,7, &c. Also the tints reflected and trans-
mitted at any given point are complementary to each other, or are such as,
united, produce white.
The measurements above given are those which correspond to rings formed
by light perpendicularly incident upon the thin lamina. But when the rings
are observed obliquely, their diameters are rapidly enlarged with increase of
obliquity. Sir Isaac Newton ascertained the law of this increase to be this:
that the squares of the diameters are inversely as the cosines of incidence.
When the incidence exceeded 602, it appeared to him that this law no longer
held good; and this conclusion, which, up to a recent period, had not been
invalidated, has formed a serious difliculty in the way of any theory of light.
Recent experiments, however, made by Messrs. Provostaye and Desains, with
monochromatic light, and with special arrangements to eliminate the sources of
error in measurement which must have vitiated Newton’s results at high inci-
dences, have fully established the universality of the law. ‘Their measurements
extended to the forty-third ring, and to the great incidence of 86° 14’, beyond
which the rings were no longer discernible.
Colors resembling those of thin plates may be produced also, in various modes,
by means of thick plates. Sir Isaac Newton employed, in an interesting experi-
ment of this kind, a spherical glass mirror, with truly concentric surfaces, silvered
on the back. A very small beam of light (about one
twenty-fifth of an inch in diameter) having been intro-
duced inté a dark room, he received it on this mirror in
such a manner as to reflect it back toward the aperture.
ili) At the centre of curvature of the mirror he placed a white

! card pierced, in order to allow the light to pass, with a
very small orifice. Around this orifice he saw a series of
rings resembling those of thin plates. When the light
was homogeneous, the rings were alternately bright and dark as in the other case.
The diameters were also observed to follow similar laws. As both surfaces of
the mirror are concerned in producing these rings, and as, at the first surface,
it is the irregular or seattered reflection only which is necessary to the effect,
the experiment succeeds best with a mirror in which this surface is not highly
polished. Instead of the perforated card, a lamina of mica, or of slightly tar-
nished glass, may be employed to receive the rings.

When light is transmitted through or reflected by a pair of thick plates of
homogeneous glass, with parallel plane surfaces,
and placed parallel to each other. colors may ap-
pear, if the difference of thickness of the two plates
is comparable to the absolute thickness at which
such colors are produced by thin plates. ‘The
figure shows the arrangement. Dr. Brewster pro-
duced the same effects with a pair of plates of
equal thickness, by inclining one of them so that
the path of the rays within it should be slightly
longer than within the other. ‘There is some sim
ilarity between the first of these classes of phenomena and those of diffraction.
The second have a nearer analogy to the eolors of Newton’s rings.

Fig. 8.

PROGRESSIVE MOTION OF LIGHT. 1Oq

The next important step in the progress of optical science was the discovery

of the progressive motion of light, and the determination of its velocity. 'Uhough

every theory which had ever ~ been suggested to account for the phenomena ‘of
light presumed that there must be a progress from the luminous origin, and
feos that time must be an element in the solution of every optical proble m,
still so nearly instantaneous are all the effects produced at the distances to
which our ordinary observation extends, as apparently to render hopeless any
plan for experimentally determining the velocity. This circumstance rendered
the efforts made by the celebrated Galileo, and by the academicians of Florence,
to settle the question, completely nugatory. ‘The method of proceeding adopted
by Galileo was to place himself upon an eminence opposite to an assistant
observer something more than a mile distant ; both being provided with lanterns
which could be darkened by a slide. The lights being arranged, Galileo dark-
ened his lantern; and the assistant, immediately on noticing its disappearance,
darkened his also. Apparently both were extinguished at the same instant.
The Florentine academicians repeated the experiment, increasing the distance
between the stations, but the result was the same. The problem remained
unsolved ; but its solution came at last, when demanded by the exigencies of a
higher | branch of science.

In 1675 Reemer, an astronomer of Copenhagen, in his observations upon the
eclipses of the first satellite of Jupiter, became perplexed by irregularities for
which he could conceive no means of accounting. It was suggested by Dominic
Cassini that these difficulties might perhaps be re emoved by supposing that the time
occupied by light in passing through the vast distance between Jupiter and our
planet may be | arge enough to be. appreciable; and therefore that, as our dis-
tance varies, this time must vary also. Assuming this hypothesis to be true,
and that the epoch on which our computations of future eclipses are founded is
the date of some eclipse actually observed when the two bodies were occupying
their points of nearest approach, it will follow that if the accuracy of the deter-
minations is affected only by the motion of light, all subsequent eclipses,
observed when the distance is the same as at the epoch, will agree with the
prediction, and all others will be in retardation by an amount of time equal to
that which light requires to pass over she space by which the distance has been
increased. In like manner, if the epoch had been an eclipse observed in the
position of greatest distance between the bodies, subsequent eclipses would be
in advance of the prediction; and if the epoch had been an observation made
from some position intermediate between the points of greatest and least distance,
the eclipses afterwards occurring would be sometimes in advance and some-
times in retardation. The test of the correctness of the hypothesis would be a
careful comparison of the observed irregularities of time with the variations of
distance—a comparison involving no slight labor. Cassini, with whom the idea
originated, seems to have abandoned it; but Roemer followed it up with such
perseverance as at length conclusively to establish its truth. He demonstrated
that the time occupied by light in passing over the entire diameter of the earth’s
orbit is 16 minutes and 26 seconds. But at that period the dimensions of the
earth’s orbit were not accurately known, and this determination was insuflicient to
fix the absolute value of the velocity of light. Assuming the sun’s mean parallax
to be 8.6, the mean diameter of the orbit must be about 190,000,000 of miles,
and this number divided by 986, the number of seconds in 16 minutes and 26
seconds, gives for the velocity in miles 192,700.

The velocity of light has, since the time of Roemer, been ascertained, with a
probably near approximation to the truth, by ether independent methods, and
the results tend to confirm the substantial correctness of his original determina-
tion., The first of these methods is that which rests upon the measurement of
the aberration of the stars, a phenomenon discovered by Bradley, afterwards

122 VELOCITY OF LIGHT.

astronomer royal of England, in 1728. This aberration consists m an apparent
displacement of the star from its true position by the com-
2 eg bined influence of the motion of the earth and the progressive ,
Bx f, motion of light. If, for instance, the line MN be taken to
/ B represent a small portion of the earth’s path, and 8 be a fixed
PY AE 1] star, then while the earth advances in the direction of the
Wf} arrow from O to O', O””, &c., if the propagation of light were
Af fi) instantaneous through all distances, the star would be seen
__ ool old ar in the true direction, OS, O's, O"s', &c., the telescope OP
oie remaining parallel to itself as the earth moves, in conse-
quence of the immense distance of the star. Also, allowing
progressive propagation of light, if the earth were without motion, the star would
still appear in its true direction. OS, the telescope OP remaining stationary ;
but if we suppose both the earth and light to move, then a ray entering the
centre of the tube OP, at the summit, would not be in the centre of the tube
when it reached the lower end, but would be displaced toward the rear by a
small space equal to the earth’s own motion while the ray is descending the
tube. T'o the observer at O, therefore, the telescope would not appear to be truly
pointed at the star, but would require to to be leaned forward in the direction
OP, until the luminous elements which compose the ray (whatever they may
be, should follow accurately the axis of the telescope from top to bottom. The
star will accordingly seem to be at S’, in advance of its.true position, in the
direction of the earth’s motion. The amount of this apparent displacement will
vary with the angle made by the direction of the earth’s movement with the
direction of the star. When this angle is zero, that is to say when the earth is
moving di.ectly toward or from the star, the displacement is zero; when the
angle is 90°, or when the earth’s motion is directly across the line drawn to the
star, it is maximum. For a star in the plane of the earth’s orbit, the aberration
is apparently an oscillation in a straight line, the duration of the movement in
the aliernately opposite directions being six months ; for a star in the pole of the
ecliptic, or in a direction at right angles to its plane, the apparent path would be
a very small ellipse similar to the earth’s orbit. The major axis of this ellipse
would measure the maximum amount of aberration on both sides of the true
place, and this is found to be equal to 40.88; half of this, or 20”.44, is the
maximum absolute amount of displacement. ‘The direction of a star, therefore,
when its aberration is maximum, deviates from its true direction as the diagonal
of a rectangle deviates from the side. If, in such a rectangle, the smaller side
be made equal to the velocity of the earth, the larger will be the velocity of
light, and the angle between the larger side and the diagonal will be 20'.44.
But the earth’s velocity per second is known, and is about 18.9 miles; hence the
velocity of light is 18.9 x cot20’’.44—=190,730 miles, a number less than that
before obtained by about one one-hundredth part.

This coincidence of results is sufficiently remarkable, when we consider the
extreme delicacy of such measurements as those by which aberration is de-
termined, and also the difficulty of fixing, by observation, the exact instant
of the immersion or emersion of one of Jupiter’s satellites; but, these difficulties
apart, there is nothing surprising in the agreement, since both depend at last
for their absolute values upon our received horizontal parallax of the sun.

Results very nearly similar, however, have been recently obtained by experi-
mental methods founded upon principles entirely different from the foregoing.
The first of these methods was devised by Mr. Fizeau, of Paris, and executed
by him in the vicinity of that city. Having selected two stations, visible from

VELOCITY OF LIGHT. 123

‘ each other, and about 54 miles apart, he placed
fwo tubes, something like tubes of telescopes,
one at each station, looking towards each
other, with their axes in the same straight line.
One of these tubes, represented at AB, has a
branch tube E furnished with lenses, through
which is received the light from a radiant point
S. This light is reflected by an inclined trans-
parent plane mirror m, forming a bright image

of the luminous point at s, which is in the principal focus of the large lens B.
The rays being made parallel by this lens, are received at the other station upon
the lens C, by which they are brought to a focus upon the surface of a plane
mirror D. Being reflected back by this mirror, they return to the lens B, and once
more form a bright image at s, which image may he observed through the trans-
parent mirror m, by an eye placed at A. The upper side of the tube at F, just
in front of the plane mirror, is cut through in order to admit the limb of a wheel,
furnished with teeth, to descend so far into it that the i image s may be seen be-
tween the teeth or cut off by them, according to the position of the whecl. The
teeth amd the intervening spaces are of exactly equal breadth. By means of
connected gear-work a ‘high velocity of rotation may be given to the wheel,
while the number of turns per second admits of being ascertained. The
velocity may also be retarded by a brake. When the wheel turns slowly
the light is intermittent, and the passage of the teeth is perceptible, But when
as many as ten tecth pass per second, the light is constant, owing to the dura-
tion of the successive impressions upon the eye. By accelerating the movement
the brightness of the image may presently be made to fade, in consequence of
the interference of the successive teeth with the rays returning from the distant
station, after having passed through the last preceding interval between the
teeth. As the velocity increases this fading will become an absolute extinction,
each tooth in its progress cutting off all the light which passed through the in-
terval before it. When this state of things is reached, it is evident that the time
occupied in the passage of light to the distant station and back—that is to say,
102 miles—is equal to the time which it takes for a tooth to advance a dis-
tance equal to its own breadth. If there are five hundred teeth and five hun-
dred intervening spaces, this time will be one one-thousandth part of that of a
revolution; and if there are eighteen revolutions in a second, the absolute time
will be one eighteen-thousandth of a second.

By still further accelerating the velocity of rotation, the light may presently
be made to reappear; the rays which pass through one opening to the distant
station, returning through the next following opening to the eye. When the
full brightness is thus restored, the velocity will be found to have been doubled.
By carrying the acceleration still further, the light may be a second time eclipsed
and a second time restored; and, in like manner, alternately extinguished and
revived, as long as the driving power will allow: the velocities at which the
several successive extinctions and revivals occur, constituting a regularly increas-
ing arithmetical series.

We thus are enabled to measure the small fraction of a second required for
light to pass over twice the distance between the two stations; and dividing this
double distance by this fraction we obtain the velocity of light per second. The
result at first obtained by Mr. Fizeau, by means of this apparatus, was about
196,000 miles, being in excess of the results by the astronomical methods by
one-sixtieth part nearly.

It is manifest that « any mode by which very minute intervals of time can be
accurately measured, is capable of being employed as a means of dete rmining
the velocity of light. Mr. Wihtentapene. i in his researches upon the velocity of
electricity, employed for this purpose a revolving mirror; and in 1839, Mr.

LOA VELOCITY OF LIGHT.

Arago made an effort, by the use of a similar mirror, to institute a comparison
between the velocities of light in passing through water and through air. This
was suggested by him as an experimentum crucis between the opposing theo-
ries current in regard to the nature of light; in one of which light was sup-
posed to consist of material particles actually thrown off by luminous bodies,
while in the other it was assumed to be an effect of undulations propagated
through an exceedingly subtle elastic medium pervading all space. If the first
were ahie true theory, the velocity of light in a more powerfully refracting
medium should be greater than in a less; and the reverse, if the second were
true. Mr. Arago ava not carry out his design to its completion, but it has since
been successfully executed by both Mr. Fizeau, whose original method has just
been given, and by Mr. Foucault, well known for his pendulum demonstration
of the earth’s rotation. The experiment served at once to compare the veloci-
ties of light in air and water, and to determine the absolute velocity. The an-
nexed figure may render the method intelligible. Suppose a small beam of

Fig. 12.

parallel rays to be admitted into a room otherwise dark, through an aperture R,
and to fall wpon an achromatic lens, fixed at C, in the direction of its axis. Let
CD be the focal distance of this lens; and at M let the beam be intercepted by a
mirror capable of turning around a vertical axis coincident with its plane. At
a distance, ME==MD, in any convenient position not very remote from R, let
there be placed aspherical mirror having its centre of curvature in the axis of M.

Let there be, further, across the aperture R a fine wire exactly vertical ;
and in front of the aperture R a transparent plane mirror AB, inclined
to the beam at an angle of 45°. The mirror M may obviously be turned
on its pivot, so that the ray RCM falling upon it may be refle cted to E. If
it remain stationary in this position, the light incident on E will be returned to
M, and so again to the aperture R. But a portion of this returning light, being
reflected by “AB towards O, will enable an observer at that point to see the im-
age of the vertical wire. To assist the eye, a magnifying eye-piece may be em-
ploy ed, and this may be provided with a spider-line micrometer at its focus. If
the mirror be new put very slowly into revolution, the image of the wire will be
seen intermittently and momentarily, once in every revolution. ‘The spider-line
of the eye-picce is now to be brought to exact coincidence with this image.
Accelerating the revolution, when the number of turns per second becomes as
great as ten, the image will be permanent. If, now, a very high velocity be
given to the mirror, the image seen by the observer at O will no longer coincide
with the spider-line of the micrometer, but will be seen at a sensible distance from
it in the direction of rotation. Thus, if the arrow represent the direction of
rotation, the returning ray which originally met the mirror A B at 7, will meet it
at 7’ or 7’, and the image which originally appeared at S will be seen at S’ or 8S”.
This is evidently owing to the change in the position of the mirror M, while

VELOCITY OF LIGHT IN WATER AND AIR. 125
the light is moving from it to the spherical mirror E and back again; and the
angular displacement of the returning ray around the centre M will, ‘according
to the well-known law of reflection, ie double the angular change of position oF
the mirror. If the mirror makes 2 turns in a second, the time of one turn will
be the zth part of a second, and the time of making the change of position of
which the observation gives us the evidence, will be the same fraction of the nth
part of a second that Hi alf the angle subtended by RR‘ or RR", as the case
may be, at the centre M, is of 360°; or as 4RR’ is of a whole circumference.
This distance RR’ or RR", being equal to ‘SSI or SS”, is directly measured
by the micrometer. Let it be put — —0. The circumference of the circle whose
radius is RM, (which put —~7,) is 2zxr. Put the space ME=s, or 2ME=
2s, and the time of passng 2ME=¢. Also let v represent the velocity of
light. 'Then—

O 2s 8zxrns

1 9
; ana v—— — a
; t 6

her
i This expression is, however, true only on the assumption that the returning
ray suffers no deviation in passing the lens ©. But since, if its original path
was, as we have assumed, the axis of the lens, it cannot, if sensibly deviated,
return through the axis, it will be bent at C, and the displacement RM’ will be
less than we have assumed it to be. If D be the actually observed eee
and if RO be represented by 7’ and MC by s’, then the value of our assumed
displacement in the above formula will become, as may easily be shown—

Dr(s +s’)

sr!

—

Substituting this value, we shall have for the velocity of light—
Sxnr's?
~~ D(s+s/)

With a distance s = 4 metres, and 800 turns of the mirror per second, Mr.
Foucault found a value of D— 6”, whence the value of v is found to be, in
English miles, 192,950.*

By placing a second fixed mirror, I’, in any other convenient position, and
interposing a tube, as GH, filled with water or any other transparent medium,
the ends of the tube being closed with plate glass having parallel surfaces, the
velocities of light in air and such a medium may be compared, The mirrors E and
F will both give images of the wire at R; and if the value of v is the same for
both, the two images will be coincident, and appear as one; but if v have dif-
ferent values for the different media, one of the images will be more displaced
than the other. Mr. Foucault performed this experiment; and, in order to
identify the images, and to distinguish one from the other, he placed before the
mirror E a sereen having a rectangular opening, such that one-third part of the
image from that mirror should be cut off from the top, and another third from
the bottom, the central third only being left unobstructed. In the image of the
aperture at R, as seen at O, the middle third had, very sensibly, greater bright-
ness than the top or the bottom, and the wire, as reflected from E, was appar-
ently but one-third as long as it appeared reflected from F. The image from F
was sensibly the most displaced, indicating lower velocity in water than in air;
the displacement, D, in the formula above, being a factor of the denominator.

The next discovery of importance in the progress of optical science was made
near the close of the last century, by Dr. Wollaston, in his observations upon
the prismatic spectrum. He discovered that, by employing a pencil of light

* By Mr. Foucault's more recent experiments with this method, the velocity of light is
reduced to 190,249.16 miles.

126 LINES IN THE SPECTRUM.

very narrow in the direction of the plane of refraction, but broad parallel to the
axis of the prism, five well-defined dark straight lines could be distinguished
crossing the spectrum at right angles, and maintaining invariably the same posi-
tions relatively to the colors. This number he afterwards increased to seven.
These lines may very easily be distinguished by holding a prism near the eye,
parallel to any small fissure through which light makes its way into a dark
room. ‘The reason they escaped the notice of Newton and other earlier ob-
servers is to be found in the fact that those observers employed a pencil so
broad in the direction of refraction as to make the actually observed spectrum a
compound of many superposed and unconformable spectra, thereby obliterating
these very narrow markings. In fact, every point in an aperture of sensible
magnitude, through which the light experimented on is introduced into the dark
room, produces a spectrum of its own. Moreover, supposing that it is the sun-
light which is introduced through the aperture; it may be said that every point
of the aperture produces not only one spectrum, but as many spectra as there
are points in the sun’s disk from which lines may be drawn to the assumed
point in the aperture. As all these lines, so drawn, would, in the absence of the
prism, produce a white circular image of the sun upon the screen in the dark
room, having a diameter increasing with the distance of the sereen from the
aperture, it follows that, when the prism is introduced, the spectrum produced
by each point of the aperture will have a breadth equal to the diameter of this
white image of the sun, and that its elongated form is due to the lateral unequal
displacement of an indefinite number of circles, produced by the several elemen-
tary rays of which white light is made up. ‘The interposition of a convex lens
between the prism and the aperture may serve to reduce the breadth and sharpen
the boundary of the image; but still it is manifest that with a circular aperture,
there must, unless the diameter is made too small for convenient observation, be
a considerable mixture of rays of different refrangibility in every part of the.
length. It is therefore best, for the purpose of obtaining a spectrum at once
broad and pure, to employ an aperture very narrow in the plane of rebraction,
and broad in the direction of the axis of the prism. ‘This may be still further
improved by the use of a convex lens of long focus, as above described ; or bet-
ter, by the use of a cylindrical lens, with its cylindrical axis parallel to the length
of the aperture. With an arrangement like this, the lines of Dr. Wollaston may
be easily exhibited, and many more. By aiding the eye with a telescope, the
number discovered becomes surprisingly great. Mr. Fraunhofer, of Munich,
enumerated five hundred and ninety, and Sir David Brewster afterward in-
creased this number to two thousand. Their general appearance under the tele-
scope is shown in the figure annexed.

Hie Tui
—

RANGE YELLOW RE!

Hips, PS:

The eight principal lines are distinguished by the letters A to H, of which
the line A is at the beginning of the red, and the line H about the middle of the
violet. ‘The line A does not appear in the figure. The positions of these lines
being definitely fixed among the colors of the spectrum, they furnish valuable
aid in comparing the refracting powers of different bodies, and have served to
reveal the fact that bodies whose mean refractive powers are equal, do not always
equally refract the several elementary rays. The line A is not among the most
easily discernible, but Sir David Brewster has discovered others in the almost
imperceptible light below A; and Sir John Herschel, and especially Professor

POLARIZATION OF LIGHT. TAT

Stokes, have discovered many others still beyond the violet. By his curious
discovery of fluorescence, or the property possessed by some substances of ren-
dering serisible to vision rays beyond the limit of the ordinary spectrum, Pro-
fessor Stokes has in fact quadrupled its length.*

In observing the spectra formed by light from other sources than the sun, as
from the fixed stars, from incandescent solids, flames, &c., great differences are
found to exist in regard to the lines observed. In the spectra of the fixed stars,
dark lines are seen, which, like those of the solar spectrum, are unchangeable
in position, but which do not occupy the same positions. In the spectra of
flames, lines are observed which are not dark, but bright. Different salts added
to the wick of an alcohol lamp produce different systems of lines, always bright.
So, likewise, metals burned under the compound blow-pipe. The spectrum of
the electrie spark exhibits bright lines also, the positions and numbers of which
depend on the substances of which the electrodes are formed. A platinum wire
made incandescent by an electric current, gives no lines at all; and none are
seen in the spectrum formed from the light of the solid carbon electrodes which
produce the galvanic arch. Experiments made by Sir David Brewster, by pass-
ing solar or artificial light through different colored gases, led him to the con-
clusion that the dark lines are caused by absorption—an absorption which he
supposed to take place in the earth’s atmosphere.}

In the year 1808 the French Academy of Sciences proposed the problem of
the double refraction,of light as the subject of a prize to be awarded two years
thereafter. The successful competitor for this prize was Malus. To him is due
the discovery of the polarization of light by reflection. He was led to this re-
markable discovery by an accident. In observing through a prism of Iceland
spar the light reflected to his windows from those of the palace of the Luxem-
bourg, he was surprised to see that, as he turned the prism around the ray, one
of the two images vanished at every quarter revolution. By following up the
indication thus given, he arrived at the important law that, when light is re-
flected from glass at an angle of 54° 35’, or from water at an angle of 52° 45/,
it possesses all the properties which belong to the pencils into which a ray of
ordinary light is divided by a doubly refracting crystal. Accordingly, if such
a crystal be placed in the path of such a reflected ray, with the principal plane
of the crystal, or a conjugate plane, in the plane of reflection, the ray will not
be doubly refracted. But if the crystal be turned in azimuth, two rays will
make their appearance, unequal at first in intensity, but becoming equal at the
azimuth of 45°. Beyond this azimuth the ray which was previously most in-
tense fades gradually away, while the other gains in strength, until, at 90°, the
former disappears entirely, and the latter remains alone. ‘Chese phenomenaare
repeated in every quadrant. .

If the ray which has been reflected as above described be incident upon a
second surface of glass, at the same angle, (54° 39’,) as at firsi, the plane of
second reflection corresponding with that of the first, it is in part reflected and
in part transmitted, as is the case with common light; but if the second plane of
reflection be at an azimuth of 90° with that of the first, no reflection at all will
oceur, but the whole ray will be transmitted.

A ray of light therefore, which has undergone the modification which is pro-
duced by transmission through a doubly refracting crystal, or by reflection at an
incidence of 54° 35! from glass, or at that of 52° 45’ from water, seems to pos-
sess dissimilar physical properties on the sides which are at right angles to each
other, and similar ones on the sides which are diametrically opposed. This

“ The important researches of Kirchhoff and Bunsen on the chemical relations of the fixec
lines of the spectrum have been published since the preparation of these lectures.

7 Karchhoff and Bunsen have demonstrated that this absorption takes place (at least in case
ef many of the lines) in the atmosphere of the sun.

128 POLARIZATION OF LIGHT.

circumstance, from a sort of fanciful analogy which it presents with the relations
of the poles of the magnet, has suggested the name polarization, to distinguish
this condition of light.

An interesting experiment of Malus, illustrating the identity of the phenomena
of polarization by reflection, and polarization by double refraction, is the follow-
ing: Let a ray of light pass, at a perpendic ‘ular incidence, through a crystal of
Iceland spar, undergoing division into two rays; and afterwards “let these rays
fall at an incidence of 52° 45’ on water, or of 54° 35! on glass. Let then the
crystal be turned in azimuth until the principal section coincides with the plane
of reflection. The extraordinary ray will cease to be reflected altogether, though
the ordinary ray undergoes reflection as usual. Turning the crys stal once more
in azimuth, until the principal section is 90° from the plane of reflection, the
ordinary ray will, in its turn, wholly cease to be reflected, and the extraordinary
ray will revive.

Another interesting and very curious exper iment by Brewster, analogous to the
foregoing, may be performed thus: Let the light of a candle or other luminous
object be polarized by reflection, and afterward received, at the polarizing angle.
upon a plate of plane glass, which has its plane of reflection in azimuth 90°
from the plane of polarization. It will, as we have just seen, be wholly trans-
mitted, so that, to an eye placed anywhere in the direction in which reflection
would ordinarily occur, the radiant will be invisible. The. eye remaining in
thi- position, let now another person breathe upon the glass plate, and instantly
the luminous object will appear, and will continue to be seen until the film cf
moisture left by the breath has evaporated. This is because the polarizing
ang! for water is not the same as that for glass.

The ee may be varied and made still more striking by placing a
second plate by the side of the first, and adjusting this one to Y the polarizing
angl« for water. ‘The radiant wil) then be visible in the second plate, but not
in the first. In this state of things, if both plates be breathed on simulta-
neously, the light in the second plate will be extinguished and that in the first
revived by the same breath

It is only at che angles which have been mentioned that polarization by re-
flection is complete. But partial polarization takes place in reflection at any
angl-«; being zero at the incidences 0° and 90°, and. increasing from those inci-
dences up to the polarizing angle.

Light is polarized by reflection from all polished surfaces; but it is onl
the case of bodies whose indexes of refraction are in the neighborhood of 1.4
that the modification which it undergoes has the simplicity which belongs to the
examples we are considering. sue index of water is 1.336, and that of crown
glass 1.48 to 1.53.

It was the conclusion of Mules that the angle of polarization of a given body
is independent both of its refractive and of its dispersive power. Dr. Brewster.
however, demonstrated that this angle depends on the refractive power; and is
connected with it by the law that ‘the index of refraction of any body is the
tangent of the angle of polarization.”

Irom this law we derive one or two interesting consequences; first, at the
angle of polarization the reflected ray is perpendicular to the refracted ray, for,
putting « for the angle of incidence, p for the angle of refraction, and » for the
index, the law of Snellius gives us zsing—sin:; and the law of Brewster, just
mentioned, gives n—tant. Hence—

sine

tan: sino = sinp—sint; or, sine—cos:, and ¢-+p==90°.

cose
Secondly, when light falls upon a transparent plate having parallel surfaces,
if the angle of incidence at the first surface is the polarizing angle, the angle of
incidence at the second surface will also be the polarizing angle for that surface

LAW OF MALUS. 129

In this case p is the angle of incidence and: the angle of refraction for the
: ; Shel
second surface, the index of refraction being : And we have—

BUN Ec lea Or ae uM ote d a
Sint—=sinp ; or, Sint——cosp, and ¢-+p==90

tanp sine ==
cosp 4

We have seen that when the two polarized rays into which a single ray of
common light is divided by double refraction in passing through a rhomb of
Iceland spar fall upon a second similar rhomb, they are both of them subdi-
vided in most of the positions of the second rhomb; but that the intensities of
the rays of each pair are unequal, except when the principal planes of the
rhombs differ in azimuth 45°, and that one member of each pair disappears en-
tirely when the principal planes are coincident or normal to each other. The
inequality of intensity is variable, and is dependent on the angle between the
principal planes. If one ray of either pair be observed through all its varia-
. tions, it will be found to begin from zero of intensity, to increase regularly in
brightness for 90°, and then to diminish through the second 90°, to zero again.
The other member of the same pair passes through a similar series of changes,
but its maxima correspond in azimuth to the minima of the first, and its minima
to the maxima of the first.

A ray which has been polarized by reflection possesses the same character
as those which have been produced by double refraction in Iceland spar; and
accordingly, if such a ray be transmitted through a doubly refracting rhomb
which is turned in azimuth in the manner just described, it will be divided into
‘two rays which will alternately increase and diminish in intensity; and of which
one will become zero in the azimuth 0° or 90° between its plane of polarization
and the principal section of the rhomb. Assuming the united intensities of the
two rays into which a single one is thus divided by double retraction to be equal
to the total intensity of the original ray, Malus inferred that their several inten~
sities should vary as the squares of the sines and the cosines of the azimuth.
Thus, if J be put for the total original intensity and a for the azimuth, reckoned
from the position of coincidence of the plane of polarization with the principal
section of the rhomb, then the ordinary ray would have the intensity J cos’a;
and the extraordinary, I'sin’a. These values fulfil the condition of constancy
of sum; since—

Icos’a + Isin?a = I.

If a ray which has been polarized by reflection fall, at the polarizing angle,
upon a second mirror of transparent glass with parallel faces, it will be divided
into two rays; one of which will be reflected and the other transmitted. When
the second mirror is turned in azimuth around the incident ray, these two de-
rivative rays will undergo changes of intensity somewhat resembling those
which have just been described as produced by double refraction. When the
two planes of reflection are coincident, the intensity of the reflected ray will be
maximum, and that of the transmitted ray, minimum. This minimum will not,
however, be zero. When the two planes differ in azimuth 90°, the intensity of the
transmitted ray will be maximum, and that of the reflected ray, minimum.
This minimum wll be zero; and the simultaneous maximum of the transmitted
ray will be equal to the total intensity of the incident light. The alternations
in this case resemble, therefore, to a certain extent, those previously described
as produced by double refraction; but they are not represented by the law of
Malus.

The plane of polarization—an expression which we have just used without
defining it—is the plane in which a polarized ray is capable of being reflected
at the polarizing angle.. Accordingly, when a ray of common light is polarized
by reflection, the plane of incidence and reflection is itself the plane of polariza-
tion.

In the arrangement of two mirrors, as above described, when the second

s

¥
13¢ POLARIZATION BY REFRACTION.

mirror is rotated in azimuth, its plane of incidence and reflection is constantly
changing its inclination to the plane of polarization of the ray incident upon it.
Suppose the incidence upon the second mirror zot to be at the polarizing angle.
It is found that after reflection in an oblique azimuth, the plane of polarization
is nearer to the plane of reflection than it was at incidence. If the azimuth at
incidence be represented by a, and that after reflection by a’, there will be found
to be a constant ratio between tana and tana’; tana’ being always less than
tanz. By many reflections, with the same azimuth between the mirrors,
the plane of polarization may be brought indefinitely near to the plane of re-
flection; but it can never be made, in this way, absolutely coincident with it.
When common light is reflected from any surface at an angle greater or less

* . . * ° . . ° . .
than the polarizing angle it is found to be partially polarized: that is to say, it

is made up of a mixture of polarized light with common light. By repeated
reflections at the same incidence the polarization may be made sensibly com-
plete.- The number of reflections necessary for this purpose will be greater as
the angle of incidence is further from the polarizing angle.

Tt must not be overlooked that, though at the angle which we have called
the polarizing angle, all the light that is reflected is polarized, yet that this is
after all but a small portion of the incident light. From a single surface of
glass it amounts to less than eight per cent. The manner of determining this
ratio will be seen hereafter. When, for purposes of experiment, it is desired to
obtain a large and intense beam of polarized light, it has accordingly been found
useful to employ many reflecting plates placed one upon another, forming a
bundle or pile. It is obvious that the thinner these plates are made, (so that
they are not so thin as to produce color,) the more convenient they will be in
use, and, from the diminution of absorption, the more economical of light. Not
fewer than sixteen are usually employed.

The amount of light reflected at different angles of incidence goes on increas-
ing from 0° to 90°. The amount which is polar zed in the reflected beam also
goes on increasing, but not throughout the quadrant. For glass having the
index 1.5, the incidence of maximum polarization is 79°. At this incidence
the total intensity of the reflected light is expressed by the decimal 0.355, the
intensity of the incident light being 1. The amount which is polarized in the
reflected beam is, however, only 0.1518, which is still about double of that which
is reflected at the polarizing angle. But, comparing this value with the fore-
going 0.355, we shall see that it is less*than half the total light reflected, (forty-
four per cent.,) and accordingly it is not suited to exact experiments in polariza-
tion.

When a transparent reflector is employed as a polarizer the transmitted beam
will be found to contain light which is polarized in a plane perpendicular to the
plane of refraction. ‘The amount of light so polarized is exactly equal to the
amount polarized at the same time by reflection, and in the plane of reflection.
And as the maximum amount polarized by reflection from one surface of glass
having the index 1.5, is 0.1518, this also is the maximum amount which can be
polarized at one surface by refraction. But since, at this angle of maximum
polarization, the total reflection is only 0.355, the total transmission will be 0.645,
and of this amount the polarized portion will be but twenty-three and a half
per cent. But if this light, already partially polarized, be transmitted through
other refracting surfaces, though it will continually lose in total intensity by
reflection, it will gain in the proportion of the polarized light which it contains ;
and if the incidence is that of the polarizing angle for reflected light, the quan-
tity transmitted which is polarized, will continue to increase im absolute amount,
notwithstanding the decrease of total intensity, until polarized light only is trans-
mitted. Moreover, if the number of refracting plates employed should happen
to be greater than is necessary to produce complete polarization, the supernu-
merary plates will not reduce the amount of polarized light transmitted ; since,
at the incidence supposed, they are incapable of reflecting light polarized trans-
versely to the plane of reflection. This statement presumes, of course, that

NICOL’S PRISM. 1 =

the refracting surfaces are perfect, and that no light is lost by absorption in the
media.

Tt isa curious fact, resulting from the polarizing power of a pile of glass
plates, that the pile is more transparent when held at an obliquity greater than
the angle of polarization than it is at that angle; and that the transparency in-
creases with the obliquity. This is owing to the fact that the light which has
been polarized by the first few laminze undergoes very little loss by reflection
on increasing the obliquity; but the amount polarized in those first refractions
increases as the obliquity increases, more rapidly than the loss by reflection of
the natural light falling on the same surfaces is increased. The intensity of the
transmitted beam, therefore, becomes actually greater as the obliquity is greater:
a fact which is the reverse of what happens with a single plate.

A remarkable fact in regard to the condition of light emitted at great obli-
quities from luminous solids or liquids, was discovered by Mr. Arago. When-
ever the light of an incandescent body of either of these classes is examined as
it proceeds directly from the body and with no great inclination to the luminous
surface, it is found to be unpolarized. But when the rays whose obliquity to
the surface is very considerable are the subject of examination, they are found
to be partially polarized. The inference is, that these rays have been polarized
by refraction; and hence that they must have originated beneath the surface of
the luminous body. From the law of equality between the quantities of light
simultaneously polarized by refraction and by reflection, it follows that there
is areflection toward the interior of such bodies, of some of the light which
they generate. The light of flamés and incandescent gases exhibits no such
polarization.

The light of the sun is always unpolarized, whether it be examined at the
limb or at the centre of the disk. From tls observation, Arago was led to
consider the luminous envelope of the sun to be gaseous, and not liquid or solid.
An incidental corroboration of the ingenious suggestion of the elder Herschel
in regard to the constitution of the solar photosphere, is thus derived from
opties; and although that hypothesis is by no means universally received, and
though there seems recently to have been manifested an increasing disposition
among men of science to call it into question, it will be found difficult to recon-
cile the optical properties of the solar light with any supposition which implies
that the luminous-surface which we see is either liquid or solid.

In observations upon polarized light, there are some inconveniences attending
the use of a mirror, which, when turned in azimuth, obliges the observer to -
change his own position; or of a doubly refracting prism or erystal, which pre-
sents two images often not sufliciently separated. Both these disadvantages
are obviated by means of a prism invented by Mr. Nicol, which is now in

almost universal use. This contrivance is represented in

A _ FP the figure. It is an elongated rhomb, formed of Iceland

i __ # spar, its length being about three times its breadth.
d a Having been brought into this shape from the natural
Fig. 14. crystal, it is carefully sawed asunder in the plane which

divides it symmetrically through its shortest diagonal,
AD, and then reunited by means of Canada balsam. This substance is per-
fectly transparent, and has a refracting power whose index is 1.532, interme-
diate between those of the ordinary and extraordinary rays, viz., 1.654 and 1.488.
The relative index between the crystal and the balsam for the ordinary ray is
1.0796, and the limiting angle of emergence from the former to the latter is 68°.
The ordinary ray from R meets the surface, AD, at a greater angle than this,
and is totally reflected at O. The extraordinary ray passes through. The
sides of the prism are blackened to prevent a second reflection.
This ingenious contrivance is invaluable to the observer in this interesting
branch of optical investigation. Its advantages are, however, in some respects
limited. The necessary length of the prism, as compared with its lateral di-

132 POLARISCOPES.

mensions, renders it difficult to employ light of any considerable convergency
or divergency. The cost of the construction of such prisms increases also
very rapidly with their magnitude; and few have been made at all which mea-
sured more than an inch on the side. Those commonly found with opticians
are much smaller than -this.

The eye-piece of Mr. Delezenne is a very good substitute for Nicol’s prism;
although it affords a less intensity of light. In this, the surface CD is a pol-
ished mirror of black glass; ABD is a prism of trans-
parent glass. Rv, Rr, rays of light falling at the pola-
rizing incidence upon CD, are reflected at a perpen-
dicular incidence upon the first surface of the glass
prism; and after being totally reflected on AB, emerge
at right angles to the surface AD, meeting the eye of
the observer at O.

Another convenient eye-piece, which may also serve, like Nicol’s prism, as a
polarizer for small beams, is formed of a lamina of tourmaline cut parallel to
the axis. This mineral possesses the very remarkable property, when not in
exceedingly thin lamine, of suppressing one of the rays into which incident
common light is divided by it, and transmitting the other. The ray transmitted,
as in Nicol’s prison, is the extraordinary ray. Cut perpendicularly to the axis
a plate of tourmaline is opaque. Two equal plates, cut parallel to the axis, are
opaque when crossed upon each other.

The disadvantages of the tourmaline eye-piece are, first, the color of the
erystal, which mars the beauty of the tints exhibited by polarized light, and to
some extent neutralizes them. It is rather unfortunate that the crystals which
are least colored are usually bad polarizers. In this respect different crystals
very much differ. Some, which are light green, transmit a notable amount of
the ordinary ray even when quite thick. Those which polarize best are usually
brown or yellowish brown. Occasionally one of this kind will be found which
polarizes well without being very disagreeably dark. But an equal if not
greater disadvantage of the tourmaline is the great brittleness of the crystal
and the rarity of specimens in which fissures do not naturally exist. It is
difficult, therefore, to obtain clear plates of any considerable size. Finally, the
supply seems, of late years, not to have kept pace with the demand; and op-
ticlans intimate that it is almost impossible to obtain specimens fit for optical
purposes at all.

A few years since Dr. Herapath, of London, announced the discovery of a
property like that of the tourmaline, in artificially prepared crystals of the iodo-
disulphate of quinine. These crystals are but slightly colored; and could they
easily be prepared and made permanent would probably come into general use.
Dr. Herapath succeeded in obtaining specimens half an inch across.

The peculiar property of the tourmaline was also early observed by Sir
David Brewster, in agate; but that substance is not sufficiently transparent for
the purposes of optical experiment.

When large polarizers are needed, resort must be had to reflection from mir-
rors made of black glass, which reflect only from the first surface, or of trans-
parent glass whose surfaces are truly parallel. If great purity in the polarized
beam is not an object of importance, bundles of thin plates may be employed
as heretofore described, to polarize either by reflection or by refraction.

In the year 1811 Mr. Arago communicated to the Academy of Sciences of
Paris, one of the most remarkable and beautiful discoveries which has ever
been made in the history of optics. Upon examining thin plates of certain
transparent crystals, such as mica, selenite, or quartz, by means of transmitted
polarized light, he found that when the light was received upon the eye through
a prism formed of Iceland spar, the richest, conceivable colors made their ap-
pearance, which were complemertary to each other in the two images, and
which varied in intensity with the azimuth of the lamin or of the prism.

COLORS IN CRYSTALLINE PLATES. 133

When the principal plane of the prism coincides with the plane of polarization
of the light, and the azimuth of the lamina is varied, the maximum brillianey
of coloring is found in the azimuth of 45° between the principal section of the
lamina and the plane of polarization. When the azimuth is 0° or 90°, the
color entirely vanishes, and the light appears entirely unchanged. At inter-
mediate azimuths the color has an intermediate intensity, regularly increasing
and diminishing between the positions of minimum 2 ea maximum. ‘These
variations, as well as the thickness of the lamine themselves in which the phe-
nomena appeared, satisfied Mr. Arago that the colors could not be owing to the
same causes which produce the colors of Newton’s rings. Still they had evi-
dently some relation to the thickness; for it was not difficult to remove them
entirely, either by considerably increasing the thickness or by excessively
diminishing it. In the rotation of the lamina as just described, the colors
which appeared between the successive positions of minimum were always the
same in the same image. But when the lamina itself remained fixed, while the
prism at the eye was rotated in azimuth, the two images interchanged their
colors in passing each successive position of minimum.

If, instead of a doubly refracting prism as an eye-picce, a mirror, presented
to the ray at the polarizing angle, be employed, only one of the images is re-
flected; but the other, if the mirror be transparent, will be seen in the light
transmitted. In consequence of this separation of effects, Mr. ae was led
to distinguish the mirror when used in this way as the analyzer. In observa-
tions with the analyzer, then, it appears that when the lamina is snguatel in azi-
muth, the same colors come and go in the successive quadrants; but when the
analyzer itself is rotated, the colors in the alternate quadrants are comple-
mentary to each other.

The colors thus seen in crystalline laminz recur in several successive series,
as the thickness of the laminz is increased. Accordingly, if in a plate of selo-
nite we hollow out a spherical cavity of very large radius, we shall find it to
exhibit several orders of rings resembling those of Newton, and following the

same laws; though the thicknesses at which the colors of the same order oceur
are very much ereater. According to the determinations of Biot, the compara-
tive thicknesses at which the same colors app w in air, in Iceland spar, in
quartz, in selenite, and in Siberian mica, are as the numbers 1, 13, 230, 230, and
440; the thickness for selenite and quartz being sensibly the same.
The limits of absolute thickness below which pp ilas plates fail to give

colors in polarized light, are, for selenite, 0.017 in.; for mica, 0.0323 in.; and for
Iceland spar, 0.001 in. The maximum thickness for this last erystal is but six
or seven one-thousandths of an inch. Mica and selenite are therefore prepared
with facility for this class of chromatic experiments; but this is not equally
true of Iceland spar. If a lamina of selenite—a mineral which is very easily
wrought—be secured by transparent cement of any kind to a plate of glass,
very fanciful effects may be produced by grinding it away unequally in different
parts according to any definite pattern. Figures of various kinds, images of
insects, flowers, gothic windows, &c., &c., may thus be prepared, which will
come out in polarized light in very brilliant colors.

When laminz are presented obliquely to the polarized ray and the inclina-
tion varied, the colors change with the obliquity; sometimes ascending in order
with an increase and sometimes with a decrease of obliquity, according to the
character of the crystal and the direction in which the lamina has been taken
from it. For these experiments it is best to cut the laminze parallel to the
optic axes of the crystals.

If two lamine, either or both of which execed the limits at which colors are
seen, but whose d7fference of thickness is within those limits, be placed one upon
the other with their principal sections crossed—that is to say, placed at right
angles to each other—colors will be seen corresponding to those of single

134 CRYSTALS CUT ACROSS THE AXIS

lamince whose thicknesses are the differences of those employed in the experi-
ment. ‘This supposes that the lamine are of the same kind. If they are not,
the actual thicknesses are not to be employed in the calculations, but what may
be called the b:-refringent equivalents of thickness—that is to say, their measured
thicknesses divided by the numbers expressing their chromatic relation to th
plates of air which give Newton’s rings—which latter numbers may be called
their chromatic equivalents. If, then, the difference of these quotients, multi-
plied by the chromatic equivalent corresponding to the greater quotient, is
within the limits at which the crystal to which the greater quotient belongs
gives colors, the combination will give the color belonging to the value of that
product.

If the laminze belong to erystals of which one is positive and the other
negative, they are not to be crossed in this experiment, but their principal see-
tions must be parallel. This furnishes an easy test for determining whether a
given crystal/is positive or negative. Having prepared a lamina of the crystal
to be examined, (which may be of any convenient thickness,) apply it upon
laminz of Tecland spar of different thicknesses, with the principal sections sue-
cessively parallel and crossed. If the colors appear when the planes are parallel,
the signs are opposite, since, either plate being too thick to produce color alone,
the sum of their effects cannot, of course, do so. If the erystals are of similar
sign, the colors will appear when the planes are crossed.

Another class of chromatic effects produced by crystalline plates viewed in
polarized light was first observed by Dr. Wollaston in Iceland spar, in which
the display is, perhaps, the most brilliant. In these cases, the crystal is cut
perpendicularly across the axis. The arrangements for observation are the same
as in the experiments already described. If a mirror be employed as an
analyzer, and be turned to azimuth 90° before the introduction of the erystalline
plate, no light will, of course, be reflected to the eye. But the moment the
crystal is introduced a system of concentric rings will make its appearance,
colored with the richest conceivable tints, and marked by a black cross, whose
arms are in the plane of reflection, and at right angles to it, passing through the
centre.

Fig. 16. HigselT:

The ends of these arms are enlarged, and have the appearance of brushes.
If the analyzer is transparent, another set of rings may be seen by the trans-
mitted light, in which the colors will be complementary to the former, and the
cross will be white. As the analyzing mirror is revolved in azimuth, the colors
fade and a new set of rings gradually appears with colors complementary to the
first, and distinguished by a white cross. In short, in this case, the colors before
transmitted are reflected, and those before reflected are transmitted. ‘The annexed
figures exhibit the two aspects of the rings which have been just described.

CRYSTALS OF QUARTZ ACROSS THE AXIS. 135

These rings make their appearance at thicknesses much greater than those
which produce color in laminz parallel to the axis.

In examining plates of quartz cut across the axis as above described, Mr.
Arago observed a peculiarity of a remarkable kind, which is seareely found in
any other natural crystal. The centre of the field was not dark in any position
of the analyzer, but was deeply and uniformly colored with a tint which varied
as the analyzer was turned. When a bi-refringent prism was employed as an
analyzer, the two images seen were constantly complementary in color, and as
the analyzer was turned they ascended in tint, in the order of Newton’s seale,
from red to violet. Mr. Biot, in subsequent experiments, discovered that in
some crystals the ascent of the tints in the scale is produced by a right-hand
rotation, (the ordinary direction of a screw,) and in others, by a left-hand rota-
tion. These classes of crystals have been distinguished by the names right-
handed and left-handed crystals, or dextrogyre and levogyre. Sir John Her-
schel, at a later period, made the remarkable observation that these optical
peculiarities of the crystals are associated with a geometrical or crystallographic
peculiarity. The tetrahedral angles where the prism and terminal pyramid
of the crystal meet, are sometimes replaced by planes which encroach more on
the neighboring planes of one side than on those of the other. The same
occasionally happens with the lateral edges of the crystal. These faces are
called plagihedral. If, as the crystal is held in the hand horizontally, with the
pyramidal vertex toward the observer, the plagihedral faces lean to the right—
that is, if they encroach most upon the faces to the right of them—the crystal
will be found to be optically dextrogyre, and the analyzer will have to be turned
in the direction of the movements of the hands of a watch, in order that the
tints may ascend.

Sir David Brewster’s observations on these
erystals led to the discovery that, when the
crystal is not very thick the uniformly tinted field
is confined to the centre, and is surrounded by
a system of rings resembling those seen in Ice-
land spar, but in which the cross is imperfect.
The figure exhibits the appearance. He also
found in that remarkable spccies of coloxcd
quartz called amethyst, veins of right-handed and
left-handed erystallization alternating with each
other in many parallel layers, ana producing at
their surfaces of contact lines of neutral character.
In some specimens the layers were found to be

Fig. 18. so extremely thin as to neutralize the rotatory
power of the whole erystal, and in these instances the ordinary system of rings
with a perfect cross makes its appearance.

Tn all these observations upon crystals in the direction of their optic axes
the number of rings is greatly increased by the use of monochromatic light.
The intervals between the rings are also, in such light, intensely dark. In the
case of quartz crystals, monochromatic light presents appearances in the centre
very little different from those seen when the crystal is not present—that is to
say, it exhibits, as the analyzer is turned, a succession of maxima and minima,
separated from each other in azimuth 90°. But the absolute azimuths of these
maxima and minima are no longer what they were before the introduction of
the crystal: in other words, the plane of polarization has been turned to the
right or to the left, according to the nature of the crystal, through an angular
distance proportioned to the thickness of the crystal. The peculiar kind of
polarization produced by quartz has, on this account, been called rotatory
polarization.

aS

Kun

F
x
2
;

Sen

136 AIRYS SPIRALS—FRESNEL’S PRISM.

It will be easily conceived that a right
handed and a left-handed crystal of equal
thickness, superposed upon each other,
will produce a resultant rotation equal to
zero. But two such plates so super-
posed, examined in polarized light, ex-
hibit a remarkable spiral cross, such as is
seen in the figure annexed. ‘These spi-

rals were first observed by Mr. Airy, and
are commonly known as Airy’s spirals.

Two contrary plates of wnequal thick-
ness, superposed as above, produce an
amount of rotation proportional to their
difference of thickness.

The power of rotation of the same

Fig 19 crystal is different for the different colors,
being, on the undulatory theory of light, an inverse function of the length of
the undulations. By employi ing the successive colors of the spectrum | sepa-

rately, Mr. Biot determined the absolute rotatory power of a crystalline plate of
quartz one twenty-fifth of an inch in thickness, for each, as follows :

Oo Oo
extreme medina: Stow. ao 17.4964 Limit, green and blue ...... 30.0460
Limit, red and orange. ....-.-- 20.4798 Limit, blue and indigo .....- 34.5717
Limit, orange and yellow....22.3138 Limit, indigo and violet.-.... 37.6829
Limit, yellow and green... ..- 25.6752, Extreme violet 242425 .--ee 44.0827

This property of rotatory polarization does not exist in plates of quartz cut
parallel to the axis. In such plates ordinary double refraction exists ; but it is
the extraordinary instead of the ordinary ray whose velocity is least, or the
crystal is a positive one.

The physical cause of rotatory polarization is unknown. Mr. Biot supposed
it to belong to the ultimate molecules of the substance; but this hypothesis Sir
David Brewster believed to be disproved by the fact ‘that the property ceases
to appear in quartz whose crystalline structure has been destroyed by fusion.
This argument seems, nevertheless, not to be conclusive. If the BIOBCry. be-
longs to the ultimate molecules, the fact that it does not appear when the crys-

tals are examined across the axis, proves that a regular arrangement of them,
presenting their similar sides in a common direction, 1 is necessary for its display.
Fusion breaks up the regular arrangement, and thus destroys this essential
condition. ‘he fact, however, that different crystals turn the ray in different
directions, is apparently decisive against the hypothesis of Mr. Biot; and the
connexion of this difference of property with difference of cry stallographic mc di-
ficaiion,-seems to indicate that the phenomenon i is an effect of the structural
arrangement of the molecules. Indeed, it is observed, in. the fracture of quartz
crystals, that there is occasionally something actually resembling a spiral ar-
rangement of parts.

The double refraction,of quartz along its axis was experimentally analyzed
by Fresnel by means of a very ingenious arrangement. The difference of
velocity of the:two rays being so slight : as to render their separation by ordinary
cexpedients difficuli, he devised and constructed a ceepeand prism by which to
double their G@vergency. In the annexed figure, ABF and CDF represent
similar triangular prisms of right-handed quartz, with
the faces AB, CD, cut perpendicularly to the axis.
The obtuse-angled prism BID, having the angle
BED equal to the supplement of DAR B, has its
base, BD, parallel to the axis of a crystal of left-
handed quartz. The incident ray 1’ falling per-
pendiculariy upon AB, is separated into two, whose

A a

CIRCULAR POLARIZATION—FRESNEL S RHOMB. 137

velocities differ, but which pursue the same path, which is the axis. At the
surface BF their paths become different, the velocity of one of them passing
from — to +, and that of the other from + to—. At the surface FD this
divergency is increased, the velocities again interchanging their relations. At
final emergence from the face CD, the diver gency ‘will be further slightly
increased in consequence of the inclination of the emergent rays to the surface.
By this arrangement a sufficient separation of the two rays is obtained to make
it possible to examine them singly. And it is obvious that a duplication of the
system of prisms here shown, ora still greater increase in the number of ele-
ments employed, would, if necessary, make the separation still wider.

If quartz were like other uniaxial crystals in the law governing refraction
along its axis—that is, if the velocities of the two rays were in that direction
equal in this crystal as they are in others—the system of prisms just described
would produce no separation of the rays. 'The fact of the separation proves
quartz to be in this respect an exceptional case. When the separated rays are
examined, however, the extent to which quartz is exceptional is discovered to
be much greater than is implied in the difference just indicated. The peculiari-
ties are the following, and are true of either of the separated rays.

Examined with a doubly refracting prism, two pertectly equal images appear
in all azimuths of the prism. Received upon a mirror at the polarizing angle,
equal reflection takes place in all azimuths of the mirror. In these respects the
rays resemble ordinary unpolarized light.

But in the following particulars they differ: Transmitted through thin erys-
talline plates they display, on being analyzed, tints like those produced by
polarized light, only they are such tints as ordinary polarized light produces in
thicknesses of crystal greater or less, by a determinate amount, than those used
in the experiment.

Transmitted through a rhomb of glass, like that represented
in the figure, of which the acute dihedral angles are 544°, they
emerge, after two internal total reflections, at Q and P, polar-
ized in planes, one in azimuth 45° on the right, and the other
in azimuth 45° on the left, of the plane of reflection. If both
are transmitted through the rhomb simultaneously, so as to
emerge together, they will form a single ray polarized in the
plans of reflection.

Rays in this condition are said to be circularly polarized.

Fig. 21. And as it appears that a circularly polarized ray becomes plane
polarized by two internal reflections in glass, at an angle of incidence of 54° 307,
the resultant plane of polarization being inazimuth 45° from the plane of reflee-
tion, it follows that a plane polarized ray may be circularly polarized by caus-
ing it to make two similar reflections, the plane of its original polarization being
45° in azimuth from that of the first reflection. This is effected by the use of
arhomb such as has been just described, and which, from its originator, has
been called Fresnel’s rhomb. It is obvious that, ifa plane polarized ray be
thus passed through ¢wo of Fresnel’s rhombs successively, it will emerge plane
polarized.

Mr. Fresnel was led to the discovery of the remarkable property of the
thomb which bears his name, by theoretic considerations. When light is pass-
ing from a denser to a rarer medium, the angle of refraction is greater than the

oO
angle of incidence, and the law of Snellius,
sins
=A”,
sing

gives a value for m, the index of refraction, less than unity. Now as 1 is the
greatest possible sine, if we put sino— 1, we shall have sinc—=z,; and there-
fore ¢ itself less than 90°. For an incidence greater than this value of ¢ there

138 TOTAL REFLECTION—ELLIPTIC POLARIZATION.

can be no emergent ray; and hence this is called the limiting angle. For all
incidences from ¢ to 90° the whole of the light is reflected; and this is what is
meant by total reflection at second surfaces.

Mr. Fresne! found that the mathematical formule which he had deduced from
his theory of light, to express the intensity of reflection at different incidences, .
became ¢maginary in the case of total reflection; and in reasoning on the prob-
able causes of their failure, he was led to predict that a rhomb of glass, having
the angles above stated, would produce precisely the effect which has just been
described. Experiment proved the truth of this anticipation. The nature of
the modification which light undergoes in these circumstances will be more fully
explained further on.

Reflection from metals presents characters which resemble those of reflection
from the second surface of transparent media. There is this difference: that
common light ¢otal/y reflected exhibits no traces of polarization; but common
light reflected from metallic surfaces 7s partially polarized. When the incident
light at second surfaces is polarized in an azimuth between 0° and 90° the modi-
fications which it undergoes 1esemble those produced by metals. ‘This subject
was first systematically investigated by Sir David Brewster. He first discov-
ered that polarized light, after having unde:gone one total reflection in an azi-
muth between 0° and 90°, produced colors, when examined with an analyze.,
analogous to those produced by thin crystalline lamin. He afte: waids ascer-
tained that a polarized ray which has undergone successive reflections from
plane metallic mirrors placed parallel to each other, when the original azimuth
of reflection is 45° from the plane of polarization, will exhibit similar tints.
The angle of incidence at which the effect is best produced varies with different
metals, but is in all, or nearly all cases, above 70° and below 80°. The bright-
ness of the tints increases with the number of reflections.

Sir David Brewster also found this analogy between the effects of such a pair
of parallel metallic mirrors and a pair of Fiesnel’s rhombs: that at a ce: tain
angle of incidence, different for different metals, the effect of the reflection on
the first mirror would be exactly compensated by that on the second, and the
ray would emerge plane polarized. But he found also this difference between the
eases: that while (the azimuth of incidence being + 45°) the ultimate plane of
polarization with the rhombs was — 45°, that with the metallic mirrors was
always less than this, being for silver, in which it was greatest, — 39° 48’, and
for galena, in which it was least, no more than — 2°. There is also this addi-
tional and very remarkable difference: In the case of the rhombs, after the
light has undergone reflection in the first, it will be restored to its original con-
dition by the second, no matter what be the azimuth between the planes of
reflection in the two rhombs. But in the case of the mirrors, if the second be
turned in azimuth, it will no longer restore the ray, unless the angle of incidence
be changed also. If it be turned quite round, the angle of incidence required
to effect restoration will pass through a series of regular variations between
determinate limits, which variations may be represented by the varying radii of
an elfipse. It was on this account that the term e//iptical polarization was
originally applied to light in this physical condition. We shall see, further on,
that the propriety of the term may be established on other grounds.

Common light reflected from metallic surfaces is more or less elliptically
polarized. In fact, the recent investigations of Mr. Jamin and others have
proved that there are very few substances which furnish by reflection from their
surfaces absolutely pure plane polarized light. None are capable of doing so
whose indexes ‘of refraction exceed or fall short of 1.414. Water and glass do
so sensibly; but in this respect they are nearly exceptional.

CRYSTALS OF TWO AXES. 139

The rings seen in, crystals cut across the
axis, when examined in circularly polarized
light, exhibit some singular peculiarities.
They are divided into quadrants by a cross
which is neither very dark nor very brig!tt,
\ and which does not change in intensity with
' the revolution of the analyzer, but turns with
lit.’ The rings in the alternate quadrants are
unconformable, those in one opposite pair
being nearer to the centre, and those in the
other more distant from the centre, by a
quarter of an interval, than the corresponding
rings in plane polarized light. This singular
arrangement is shown in Fig. 22.

Mr. Airy found that light may be circu-
larly polarized by refraction, in passing
through laminz of erystals which doubly refract ; provided the thickness of the
laminz used is such as, on the undulatory theory of light, is just sufficient to
effect a.retardation of one of the rays produced by the double refraction, one-
quarter of an undulation behind the other, or to advance it one-quarter of an
undulation before the other. The mineral employed by him for this purpose,
and which is more conveniently prepared of suitable thickness than most others,
is mica; of which the lamine are easily separable, and cleave in large sheets
without breaking. A lamina reduced to a thickness proper to produce circular
polarization is commonly called a “ quarter-wave lamina.”

For some time after the discoveries had been made of which a brief account
has here been given, it was supposed that all doubly refracting crystals have
but a single optic axis. In the year 1817, however, Sir David Brewster
announced the remarkable fact that most crystals have two optic axes instead
of one. The rings seen in crystals of two axes are elliptical, when the axes are
so far apart that only one can be observed at a time; and thcy form lemniscate
curves, or curves resembling the figure 8, when they are near together. In topaz

Nh
nT i

att ta
Ai aa Wy nn
ya |

na ‘I
Ny Ni Ni
i au Ki — NTN
i wt Ay, r
\ d 1 " INN
Ni '
i ‘ ‘

sili tl

Fig. 23. Fig. 24.

the axes form an angle with each other of 65°, and the rings present the appear-
ance shown in Fig. 23, when the analyzer is crossed upon the polarizer, the
plane of the axes of the crystal being in azimuth 0° or 90°. This erystal pos-
sesses the peculiarity of showing its own rings without the help of an analyzer
when the plate subjected to experiment is cut across the line intermediate
between the axes, the opposite surfaces being parallel. In such a plate, in order
that the ray may follow the line of one of the axes within the crystal, its angle
of incidence must be 624°. The angle of refraction will then be 32$°. The
incident angle at either the first or the second surface will, therefore, be very
nearly equal to the polarizing angle for the substance, since the reflected and
refracted rays make an angle of 85° with each other; whereas, according to
the law of Brewster, at the polarizing angle they should be at right angles.
If, therefore, instead of observing the light transmitted through the plate, we

140 | POLARIZING STRUCTURE ARTIFICIALLY PRODUCED.

veecive upon the eye the rays reflected from the second surface and emergent
from the first, the reflecting surface itself forms an analyzer sufficiently perfect
to exhibit the rings. But as the angle of reflection is not truly the polarizing
angle, when the crystal is in azimuth 90° the dark band will not be as large as
is the case in the rings seen with a better analyzer by transmitted light. Fig.
24 exhibits the appearance of these reflected rings.

In Figs. 25 and 26, which follow, are seen the appearances presented when
the subject of examination is saltpetre, (nitrate of potash,) in which the axes
are inclined to each other 6°. The plane of the axes of the crystal being brought

Hig. 26,

into coincidence with the plane of polarization of the incident light, and the
analyzer being crossed upon the polarizer, a system of lemniscate curves is
seen, like that shown in Fig. 25, intersected by a dark cross, of which the bar
coinciding in direction with the plane of the axes is longest. If the analyzer
be turned 90°, the colors become complementary, and the cross becomes white;
but if, the analyzer and polarizer remaining fixed, the crystal itself is turned in
azimuth, the cross will break at the centre, forming two curves, which, when
the rotation becomes forty-five degrees, assume the form of two opposite hyper-
bolas. This appearance is exhibited in Fig. 26.

In the prosecution of his investigations, Sir David Brewster arrived at the
discovery that the polarizing structure could be artificially produced in glass by
heat or by rapid cooling; that this effect is transient when the heat is below
the point of softening or fusing the substance; but that when it is carried beyond
that point, and cooling rapidly follows, as in glass which is not annealed, the
structure is permanent. He found that the same structure could be produced
by pressure, by torsion, by tension, or by flexure; and traced the transient con-
dition of the same kind produced by heat to the mechanical effects of unequal
expansion. Any solid transparent substance, organic or mineral, was found by
him to be capable of receiving this structure transiently or permanently. Among
these may be named horn, indurated jellies, tortoise shell, gums, resins, the
crystalline lenses of fishes or animals, &c., &c.

When cylinders, tubes, rhombs, or other geometrical forms of well-annealed
glass are subjected to a sudden increase of temperature acting upon all their sur-
face, as by immersing them in hot water or hot oil, there will be seen within
them, by polarized light, systems of symmetrical figures, circular and concentric
in cylinders, and dependent on the form of the solid for their shape in other cases,
bearing a striking resemblance to the rings seen in crystals. Like those rings,

5
these figures are marked by a cross, which changes from black to white with

-ROTATORY POLARIZATION OF LIQUIDS. 14]

the rotation of the analyzer. But these figures will alter their forms if the glass
be broken, which is not true of the rings formed in crystal. When the heat
has fully penetrated the glass, and the interior temperature is uniform, the
figures cease to be seen. At this time, if the heated glass be removed from the
bath, and allowed to cool rapidly, a new system of figures will spring up within
it. This is related to the former one, as the rings of a positive erystal are to
those of a negative one; and, therefore, if two similar solids, in one of which
the former set of figures is seen, and in the other the latter, be superposed when
the intensities are equal, they will neutralize each other’s effects, and the rings
will disappear. ‘This structure may be made permanent in the glass solids we
have been considering by heating them nearly to the point of fusion and then
suddenly cooling them. Many common articles of glass are so imperfectly an-
nealed as to display the doubly refracting structure in a striking manner. The
stoppers of bottles, if cut across the axis and polished, will invariably show it;
so will the stems of wine glasses, the stirring-rods of the chemist’s laboratory,
and many, if not all, glass tubes.

The effects of heat are also remarkable in altering the doubly refracting
character of crystals. Mr. Mitscherlich discovered that heat expands crystals
unequally in different directions. Iceland spar is expanded in the direction
of its axis, and slightly contracted at right angles to the axis. Its doubly re-
fracting power is thus diminished. In sulphate of lime, which is a crystal of
two axes inclined to each other 60°, he found that the inclination diminishes
with elevation of temperature, until the two axes unite in one; after which,
with further increase of heat, they open out ina plane at right angles to the
first. Dr. Brewster discovered an example even more remarkable in glauberite.
At the freezing point, this crystal has two optic axes for every color of the
spectrum, the inclination of the axes of the red being greatest, and that of the
violet being least. At ordinary temperatures it has two axes for red and one
for violet. When heat is applied, the other axes approach, as in the case just
described, and, after successively uniting, successively open out in the transverse
plane.

In comparing the erystals which possess the power of double refraction, (being
by far the greater number of the whole,) there is found to be a certain relation
between the optical character of the crystal and the erystallographic structure.
All crystals whose primitive form is the cube, the regular octahedron, or the
rhomboidal dodecahedron—figures whose geometrical axes are all equal—are des-
titute of the property. All crystals which have one axis greater or less than the
others are crystals of one optic axis. All crystals whose geometric axes are all
three unequal have two axes of double refraction.

In the year 1815, Mr. Biot made the remarkable discovery that many liquids
possess the power of rotatory polarization—a discovery which was independently
made by Mr. Seebeck ; the effect was first observed in oil of turpentine, but has
since been found in most essential oils, in solutions of sugar, dextrine, the vege-
table alkaloids, camphorie and tartaric acid, and the tartrates. In some of these
substances the plane of polarization is turned to the right and in others to the
left. Their relative rotatory forces are estimated by a comparison of the amount of
angular change in azimuth produced upon a polarized ray in passing through a
column of given length; but as yet there has been no universal agreement upon
astandard length. ‘The statements of experimenters, therefore, usually-embrace
both the angular rotation and the length of the column by which it has been
produced, rendering a reduction to a common length necessary before a correct
comparison can be instituted. It would perhaps be most convenient to adopt
as a standard length, the length of the tube introduced by Mr. Soleil into his
saccharimeter, or instrument for measuring the rotation in solutions of sugar,
which is twenty centimetres. With this length the dextro-gyration of the oil
of bitter oranges is, for red light, 157°.89, which is the maximum observed in

142 HEMIHEDRISM——-THE TARTRATES.

this class of’ liquids. The laevo-gyration of narcotine, in alcohol and ether, is
151°.4; that of sulphate of quinine, in water acidtlated with sulphuric acid, is
192°.95 in the same direction. Solution of crystallizable cane sugar is dextrogyre ;
that of uncrystallizable cane sugar, or molasses, is levogyre. Solution of sugar
of grapes is also dextrogyre when prepared from the juice, and before solidifica-
tion; but if evaporated to dryness and redissolved, it is levogyre. Crystallizable
cane sugar is made uncrystallizable by heat, and its rotatory power is accordingly
reversed by the same cause. In many solutions the introduction of an acid
modifies the rotatory power. Narcotine, from being —151°.4, becomes, after the
addition of hydrochloric acid, +83°. Cane sugar has its rotatory power inverted
in the same way. Upon this principle is founded the construction of Soleil’s
saccharimeter just mentioned. A solution of the sugar to be examined is made
of a definite density, and its rotatory power observed in a tube twenty centimetres
in length. There is then added to the solution a measured amount, one-tenth
of its volume, of strong hydrochloric acid, and a heat of about 150° F., applied
for ten minutes; after which it is cooled and observed again in a tube one-tenth
longer than before. Its rotation will now be wholly negative. The original
observation will give the difference between the rotatory effects of*the crystal-
lizable and unerystallizable sugar present, and the second observation will give
the sum of the same effects. From these data the relative quantities of the
two kinds contained in the solution may be deduced. For convenience, tables
to accompany the instrument are prepared in advance, from which the values
sought may be found by inspection. A saccharimeter has also been contrived
by Mr. Mitscherlich.

Mr. Pasteur has made a very elaborate examination of the salts of tartaric
and paratartaric acid in their relations to polarized light. All the tartrates are
dextrogyre; the paratartrates have no rotatory power at all. Myr. Pasteur made
the interesting discovery that paratartarie acid which is the same as racemic, and
which differs from tartaric acid only in having an additional atom of water, is
composed of two acids, one of which has a positive and the other a negative rota-
tory power. The dextro-racemic acid is simply tartaric acid, and the dextro-race-
mates are tartrates. Paratartaric acid and its salts owe their neutral character
to the balance of opposite forces belonging to their components.

In considering the crystalline forms of these different salts, Mr. Pasteur de-
tected a relation between them and their polarizing properties, such as has already
been described to exist in quartz; that is to say, the salts which possess rota-
tory power have plagihedral faces leaning in the direction of rotation. The
crystals are all of the kind called by Mr. Weiss hemzhedral ; that is to say, not
in all respects symmetrical. Mr. Pasteur observed that there are two kinds
of hemihedral crystals, which he has distinguished as the superposable and the
non-superposable. When a crystal, or any solid, or surface is such that another
may be conceived or constructed like it in every particular as to form and dimen-
sions, yet incapable of being made to oceupy the same matrix or mould, such a
crystal, or solid, or surface belongs to the class of the non-superposable. 'The
image of the face in a mirror, as compared with the face itself; the left hand or
the left foot, as compared with the right, and many analogous objects natural and
artificial, may serve to illustrate this conception. Mr. Pasteur found that all the
crystals whose salts possess the rotatory power are hemihedral and non-super-
posable; and, conversely, that all salts whose erystals are non-superposably
hemihedral have the power of circular polarization, with two exceptions only
thus far known, which are formiate of strontian and sulphate of magnesia. In
the latter case the crystal is so very nearly superposable, that it is hardly sur-
prising that it should not sensibly conform to the law. In the instance of the
formiate of strontian, Mr. Pasteur thinks that the hemihedrism does not depend
on the arrangement of atoms in the chemical molecule but on that of the physi-
cal molecules in the entire crystal; so that, on solution, the structure on which

ATMOSPHERIC POLARIZATION. 143

the rotatory power depends, disappears in the same manner as it is known to do
in quartz on fusion. It is impossible within the limits to which we are here
confined to pursue this interesting subject further.

Mr. Arago early made the discovery that the light which comes to us from
the atmosphere is polarized. Observations made in the vertical plane passing
through the sun show sensible polarization in that plane up to about 150° from
the luminary—a point which can only be observed, therefore, when the sun is
low. The polarization at this point becomes: zero, and it is hence known as
Arago’s neutral point. Below this point down to the horizon, polarization is
found in a horizontal plane. Mr. Babinet discovered a second neutral point 17°
above the sun, and Dr. Brewster a third, 8° 30’ below. Neither of these is
easy of observation. in consequence of the proximity of the sun himself and his
ereat light. Between them the light is probably polarized horizontally; but the
fact, for the reason just mentioned, has not been verified. The plane of polar-
ization in the vertieal between the neutral points of Arago and Babinet is easily
accounted for by ascribing the polarization itself to direct reflection of the sun’s
rays from the molecules of. the atmosphere. The polarization in a horizontal plane
below Arago’s point is a less simple phenomenon. It is believed, however, to
be oceasioned by rays which have undergone two reflections from the atmos-
pheric molecules. Of the rays of this class those which will come most effectively
to the eye of the observer will be such as are reflected in the lower parts of the
atmosphere in planes nearly parallel to the horizon. These will, of course, be
polarized in planes nearly horizontal, and if in force sufficient to overcome the
light polarized vertically, will produce a resultant in their own direction. At
an altitude at which the two opposite polarizations balance each other, will be
found a neutral point, and this is the point of Arago.

Regarding atmospheric reflection of the sun’s rays as the cause of atmospheric
polarization, it will follow that every plane passing through the sun (in the
superior portions of the atmosphere at least) must be a plane of polarization.
This will therefore be true of the howr-circle or meridian in which the sun
happens at any time to be. And as all hour-cireles pass through the pole of the
heavens, it results that a delicate polariscope, directed toward the pole, may
follow the horary motion of this plane. Such a polariscope, furnished with a
dial and index, becomes a chronometer. This is the principle of an elegant
little instrument invented by Wheatstone, called the polar clock. When acecu-
rately adjusted, it will indicate, in the hands of a practiced observer, the
apparent solar time within a very few minutes. It will operate even when the
sky is overeast with clouds, provided there be an unobscured spot at the pole,
through which the blue sky may be seen.

In the foregoing very suceinct outline of the history of optical discovery, the
object kept in view has been to present simply facts, without entering into any
discussion of the physical causes to which they are to be attributed. It is now
proposed to consider in what manner these facts may be most satisfactorily
explained.

THEORIES OF] LIGHT.

Two theories have been maintained in regard to the nature of light, either of
which is supported by the authority of very illustrious names. According to
the first of these, light is a material emanation thrown off by the luminous body,
and its particles constantly traverse and fill the entire illuminated space, so long
as the source continues unexhausted. According to the second, there is no
transfer of matter from the source of light to the surrounding region, but there
is a transfer of force through the medium of an elastic fluid which fills all space,
and whose molecules in contact with the luminous body, being disturbed by that
body, transmit the disturbance to those more remote, by means of undulations

144 MATERIAL THEORY OF LIGHT.

which succeed each other uninterruptedly until the cause which produced them
ceases to act. The first of these two hypotheses seems to have been of very
early origin. It received the sanction of Newton, and was made by him the
basis of his reasonings in regard to optical phenomena. It is hence commonly
called the Newtonian theory. Until an advanced period in the present century
it may be said to have been the generally accepted theory. Laplace, in his
great work on celestial mechanics, has founded all his investigations in regard
to aberration and astronomical refraction upon it.

Yet it must be admitted by its advocates, if there remain any who adhere to
it still, that it presents, even before we follow it into its applications to the ex-
planation of the phenomena we have described, many serious difficulties. In
the first place, if light consist of material particles, these particles must be of
inconceivable minuteness, or their living force would be sufficient to destroy
every structure, no matter how solid or how tenacious it might be, which they
should encounter in their flight. A single grain of matter, moving with the
velocity of light, would have a quantity of motion equal to that of a cannon ball
of 100 pounds weight, moving with the velocity of 1,500 feet per second. But
since destructive power is proportioned, not to the quantity of motion, but to
the living force, which varies as the square of the velocity, a single grain of
matter moving with the velocity of light would have a destructive power equal
to that of a mass of 3,350 tons moving with the velocity of 1,500 feet. If light
be material, therefore, its particles must be many millions of times less in
weight than a single grain. We have no instruments sufficiently delicate to
detect a weight so minute. Still it would be possible, by optical arrangements,
to concentrate many millions of particles upon a single point. Attempts have
been made to test the question by the use of such expedients. Dr. Priestley, in
his History of Light and Colors, deseribes an experiment in which he directed
the light of the sun, by means of a concave mirror having four square feet of
surface, upon a balance of exceeding delicacy, without producing any sensible
impression. The conclusion is expressed in his own words, as follows: “ Now
the light in the above experiment was collected from a surface of four square
feet, which, reflecting only about half what falls on it, the quantity of matter
contained in the rays of the sun incident upon a square foot and a half of sur-
face in one second of time, ought to be no more than the twelve hundred millionth
part of a grain.”

Dr. Priestley does not consider that, in such an experiment, it is the moment,
and not the weight, of the particles of light that would be measured. The
amount of inertia in any balance, however delicate, is sufficient to render it an
instrument not very well adapted to the purpose in view. 'The presence of the
air is also a disadvantage, both on account of its own resistance to motion and
on account of the currents created by the heat which attends the direction of
the solar focus upon any solid. The following experiment by Mr. Bennet avoids
these objections. This brief account is taken from Professor Lloyd’s Essay
on the Undulatory Theory, edition of 1857. ‘A slender straw was suspended
horizontally by means of a single fibre of the spider’s thread. 'To one end of
this delicately suspended lever was attached a small piece of white paper, and
the whole was enclosed within a glass vessel from which the air was withdrawn
by the air-pump. The sun’s rays were then concentrated by means of a large
lens, and suffered to fall upon the paper, but without any perceptible effect.”
These results are negative, it is true, but it must be admitted that they are such
as to render the truth of the material theory of light in the highest degree
improbable.

Another difficulty in the way of this theory is found in the uniformity of
velocity with which light reaches us from distances all but infinitely unequal,
and from luminous bodies of every magnitude. This equality of velocity in the
propagation of the light of the stars is evinced in the universality of the law of

THEORY OF EMISSION—DIFFICULTIES. 145

aberration. But it might be inferred from the equality of the refraction which
all light, whether natural or artificial, undergoes in passing from medium to
ee dian Now, if light be material, it must ie regarded as subject, like all other
projectiles, to retar dation by the gravitating power of the weds from which it is
emitted. And, moreover, it is a phenomenon inconceivable that so perpetual a
shower of projectiles, so infinite in number, should all be thrown with the same
initial velocity, and that this initial velocity should be the same for every source.
The only hypothesis upon which it is possible to mect this last objection is to
assume, according to a suggestion of Mr. Arago, that the eye is insensible to
luminous impressions, except for a certain definite velocity of the luminiferous
particles, or for that narrow range of variation of velocity, within which are
embraced the velocities which we attribute to the different colors in refracting
media.

In regard to the retardation of the particles by the attracting power of the

luminous body itself, it may be observed that, with our present means of
measurement, this would not be appreciable for distances so small as that which
separates us from the sun, or even for distances no greater than the extreme
dimensions of the solar system; at least without supposing an enormous increase
in the mass of the luminous body beyend that of any aggregated form of matter
known to us. An attracting body can destroy, in a projectile thrown from it,
no greater an amount of velocity than it can impart to a material mass falling
toward it. And this limit is reached if we suppose the falling body to commence
its motion at an infinite distance. Now, the velocity acquired by a body falling
from an infinite distance to the sun’s surface, under the influence of solar at-
traction, would be less than four hundred miles (391 miles) per second; and of
this velocity about fourteen-fifteenths (365.1 miles) would be acquired after
passing the limit of the earth’s orbit. But the body would be twenty-seven
and a half days in reaching the sun after passing this limit, while light is only
eight minutes and thirteen seconds in traversing the same immense space. The
effect of an accelerating or retarding force being as its time of action, and, in
this case, the two times to be compared being in “the ratio of about one to four
hundred and eighty, it may easily be shown that the retardation of light by
solar attraction, during its transit from the sun to the earth, could not be so
much as a mile per second in its velocity.

But the light of stars coming from distances so vast as to require years, and
many years, to reach us, must undergo such retardation as to render aberra-
tion a phenomenon exceedingly variable, unless we admit Mr. Arago’s assump-
tion just mentioned in regard to the sensibility of the retina. Moreover, in
cases in which the rays, in their long travel, had becbme reduced to velocities

paratively moderate, the gravitating power of heavy bodies near which they
mit pass, ought to produce a acasible: deflection of their course, and. modify, in

a remarkable manner, the phenomena of occultations. Nothing of this kind is
observed. It is here assumed that there may be suns much more massive than ours.

Laplace has examined the question, what ought to be the mass of a luminous
body, in order that its gravitating power may be great enough to destr roy the
velocity of the particles “of light entirely, at some distance less than infinite—
the initial velocity being assumed to be that which observation has determined
in the sunlight as it reaches us. ‘The expression for the velocity acquired in
falling from an infinite distance to the sun’s surface—his mass being assumed
to be unaltered, is—

2mgr
om
in which m is the sun’s mass, that of the earth being unity; g¢ is the measure
of the foree of gravity at the earth’s surface, being the velocity it is capable of
imparting in one second, or 321 feet; 7 is the earth’s radius, and R the radius
108

146 THEORY OF EMISSION—-DIFFICULTIES.

of the sun, both expressed in feet. If we put v == 192,700 miles, (reduced to
fect,) and make m indeterminate, we shall find that the mass must be increased
860,000,000,000 fold to be capable of creating, and therefore of destroying, a
velocity equal to that of light. ‘This supposes the bulk of the sun to be un-
altered. But if she mass is increased without altering the density we shall
have—

2mgrax?

ese
in which z is the radius of the sun under its supposed enlargement ; whence—
—_ oR®
as rv 22mg

Replacing the symbols by their values, we find that the sun must be enlarged
to nearly five hundred times his present diameter in order to possess the power
of entirely arresting the progress of light, considered as material, at any distance.
The surface of such a sun would extend more than seventy millions of miles
beyond the orbit of Mars. That there may be bodies in the universe so large
as this is possible, but we may esteem it hardly probable. If there are, and if
light is material, they may be invisible to us.

A final objection to the material theory of light is found in the phenomena of
refraction and reflection. This, though it seems to have been overlooked, is
really the most serious of all. We have seen that the effect of the immense
power of solar gravitation is insufficient to produce more than an inappreciable
variation in the velocity of light, during the nearly eight minutes and a quarter
which is occupied in its passage over the space between us and the sun; and
yet, if the hypothesis we are considering be true, there is a force residing in the
superficial stratum of transparent bodies—a stratum so thin that no attempt has
ever been made, or can be made, to measure it—which is capable of instantane-
ously doubling and, in some instances, almost tripling this velocity. Thus
light which has passed the surface of glass of antimony or chromate of lead
must, if this theory is true, have its velocity raised, in the instant of passing,
from 192,700 miles to 574,000 miles per second. In common glass the velocity
becomes 289,000 miles. In ordinary reflection, also, the reflecting force has
first to destroy the original velocity, and then to impart an equal velocity in
the opposite direction. This is more easily conceivable than the acceleration
produced by refraction, as it corresponds with the ordinary phenomena of elas-
ticity. But refraction, on the theory we are considering, is only explicable on
the hypothesis of attraction; and the immensity of an attracting force which is
capable of accomplishing in so short a time what gravity is totally unequg] to
in a time greater beyond measure, is totally inconceivable.

But, if objections of this weighty description to the material theory of light
did not exist, the impossibility of finding in it any satisfactory explanation of
the remarkable phenomena which have presented themselves in the later pro-
gress of optical discovery, would be conclusive against it; while the opposing
theory finds in these very phenomena its strongest recommendation to accept-
ance. It is to that theory, therefore, that attention will be confined in the fol-
lowing attempt to conncet the facts which have been detailed with their proba-
ble causés. ‘To repeat the imperfect explanations which have been founded on
a hypothesis which is now generally abandoned, would be an unprofitable waste
of time and space.

THEORY OF UNDULATION—VIBRATION. OG

PART Hi.

UNDULATOERY THE OR Y.

§ I. VIBRATION.

In order to understand the mode in which undulations are propagated through
an elastic medium, it is necessary to attend first to the subject of vibration. If
a body be so held in equilibrium between opposing forces, as that, when dis-
placed from its position of repose, it is urged to return by a force always pro-
portional to its distance from that point, then the time occupied in returning,
supposing it to be left at liberty to obey this impulse, will be the same, what-
ever may be the magnitude of the displacement. Moreover, if the extent or
amplitude of the displacement be taken as a radius, and a circle described about
the point of repose as a centre, the velocity of the body in its returning move-
ment will be proportional, at every point of its path, to the per-
pendicular to the path drawn from that point and cut off by the
circular are. Thus, if C be the point of repose, and CA the
amplitude of displacement, the force urging the body to return
being proportional to CA, CI’, CH, &c., when the body is at the
: points A, I’, and H, then the velocities at these several points will

Fig 27. be proportional to zero at A, to EF at F, and to GH at H.
These elementary propositions in physics, which admit of easy demonstration,*

*The demonstration referred to is the following: Put CA—a, CH=z. Put also ¢ for the
time from the beginning of movement, v for the velocity, and p? for the force drawing the body
toward C at the distance umty. Then if dx be the small space described in the small time
dt, rdt—=—dz; dx being negative because, when v is increasing, it diminishes z.

Also, if dv be the small increase of velocity in the time dt, we shall have the force, at the
distance z, equal to p*z, and p*adt—=dv. Whence,

vdv =— p*zdx; and v7? =— p?2? ++ C,
But when v= 0, =a: consequently,
v= p(a?—zx?); or, v= pV a?—x?=(in the figure) pV CR — CH? =p.GH.

Therefore v is proportional to GH. Also, the time of vibration is constant, irrespective of
the value of a. For, substituting in the first equation the value of » just found,

— —dx
pV @—a.dt=—dz ; or, ee
pV a ae
ye Tela
This gives t=—~sin —-+C.
Pp a
lf et 1 ly
When t=0, z=a: whence t=—=— | 90°—sin a) = 1COSieSs
Pp a p a

Now, taking ¢’ and ¢” for two particular values of t, one at the beginning and the other at
the end of a complete double vibration, t’’ — t’ will be the duration of the vibration, and will

i.
p : —ly P ; .
be measured by the increase which the are cos ~ undergoes during one complete series of
a

5 vw. ee aie eke : ele hire : :
all the possible values of ~ in diminishing and in increasing order—that is, from «=a to x
a

=-+qaagain. Hence, putting r=t//—t'= the duration of a vibration, we have,

me (20 (m-++1)—27m) Bee which is constant.
P P

The symbol a disappears from this expression, showing that the duration of the vibration is
independent of the amplitude.
We have here also a proposition essentially the same as that demonstrated by a different

148 UNDULATORY THEORY OF LIGHT.

may be assumed as established. When the body in its return arrives at C, it
will accordingly be moving with the velocity represented by CD, the radius of
the circle, and its inertia will carry it forward in the direction CB. It will now
be resisted by forces similar in degree but contrary in direction to those which
urged it from A to C, and its velocity will decrease as it before increased, until
it is brought to rest again at B, when it will once more return. Supposing no
forces or resistances to be called into action but those embraced in our hypothesis,
there is no reason why this reciprocating motion should not continue indefinitely.

We have an approximate illustration of the case under consideration in an
ordinary pendulum. When the pendulum is drawn from the vertical position,
the component of gravity which urges its return is a force very nearly propor-
tional, at every instant, to its distance from the position of rest. Were its path
a cycloidal instead of a circular are, this proportionality would be rigorously
exact. Its beats are therefore sensibly equal in time, whether it swing through
twenty degrees or through only one.

If we suppose the pendulum to be so suspended that its vibrations are not of
necessity restricted to a single plane, we shall be able to conceive, without much
difficulty, what must happen in another case important to be considered, viz:
that in which a body, already in a state of vibration, is acted upon by a second
disturbing force, not directed in the same plane with the first. To simplify the
‘supposition as much as possible, let us imagine that, at the moment when the
body, in its return from A, is passing the centre C, it receives an impulse in the
direction D, at right angles to its actual movement, capable of giving it, in-
stantaneously, the same velocity towards D, which it already has towards B.

By the law of the composition of forces, it will take the direc-
R_2— _™ tion CM, which is the diagonal of the rectangle formed upon
CB, CD; and its subsequent vibrations will be represented in
= RB extent and direction by the lime NM. It will be seen that the
yo extent of its excursions in the direction AB remains unaltered,
Pe since the lines MB and AN are parallel ; but it performs, at the
same time, an equal vibration in the direction DP, since DM

Ries and NP are also parallel.

Let us suppose, however, that the second impulse takes effect on the body
not at the point C, of its greatest velocity, but at A, where its motion is null,
and at the instant when it is about setting out on its return to C. It will
vibrate, as before, between the parallels NP and MDR;; ‘but it will reach the
limits of its vibration in this direction when it is at the middle of the vibration
in the other. At the end of half a vibration, therefore, it will be found at D
instead of at C, as in the former case; at the end of the next half at B; at the
end of the third half at P; and at the end of the fourth, or of a complete double
vibration, at A, the point of starting. Apparently, therefore, under these cir-
cumstances, the orbit of the body is a circle. We shall see that this is really so.

In fact, if we represent by 7 the radius vector of the body, and by
x and y its co-ordinates to the axes AB and DP, we shall have the
equation 2?+7’==7*. Whence, taking the differential—

A

zdxz+ydy =rdr. (a)

method, a little further on in the text, in regard to the measure of the time elapsed since the
beginning of the vibration, at any given moment, and in any position of the vibrating body.

Since t varies as cos it is obvious that, if a circle be described on the path of the vibra-
a
ting body as a diameter, and if an ordinate to the circumference be drawn from the position
of the vibrating body at any moment, the are of the circle intercepted between the origin and
this ordinate will be the measure of the time elapsed since the vibration began. The are must
be taken always in the same constant direction around the circumference, and the ordinate
must be positive for the advancing and negative for the returning movement. In like man-
ner, the are intercepted between two such ordinates, will measure the time intervening between
the moments when the vibrating body occupied the points from which the ordinates are drawn.

VIBRATION. 149

Now, by the law of velocities above given, if @ be put for the maximum ve-
locity, or that which the body has in passing ©, and if ¢ be put for the are of
the circle on AB which is included between the origin, ae and y, the velocity
in the direction AB, will be asing; and that in the direction CD, acose¢.
Hence, for the differentials of the co-ordinates x and y, we have, putting ¢ for
the time—

dx—=— asingdt; and dy = acos¢dt.

But by construction z—rcos¢g, and y=rsing.
Substituting these values in equation (a) there results—
— arsingcosgdt+ arsingcosgdt = rdr.
dr
Or, — =
dt
From which it appears that the radius vector is constant and the orbit a circle.
Also the motion in the circle is uniform. For if dg be the increment of the
arc,
dg? = dx’? + dy’.

i

And substituting the values of dx and dy, given above, we have,
de’? =a’ sin*¢dt? + a’cos*ed?’ =a'dt’.

And Ue Sy es)
dt

That is to say, the velocity of the movement in the circle will be uniform, and
will be equal to the maximum velocity of the plane vibration.

Hence it follows that if, at the moment when a body, vibrating in a recti-
linear path, is at the limit of its movement, a second body sets out from the same
point, in a circle of which the path of the first is a diameter, with a uniform ve-
locity equal to the maximum velocity of the first, the line which joins the two
will move parallel to itself, and will always be perpendicular to the path of the
plane vibration.

We hence obtain a convenient measure of the time which has elapsed since
the beginning of ieee Oy when the body is at any point, as H, Fig. 27, of its
path. ” For, taking as the unit of time the duration of a complete double vibra-
tion, and employing the ordinary symbol, 2z, to denote the circumference of a
circle whose radius is 1, 27¢ may express the entire space passed over by a body
making its revolutions in such a circle isochronously with the movements of the
vibrating body, and ¢ (whether its value be integral or fractional) will then de-
note at once the number of vibrations which have taken place and the number
of units of time which have elapsed since the beginning. Assuming the starting
point to be at the commencement of adouble v ibration, every integral value of Z
will denote a return to the original position, and every fractional excess will de-
note a corresponding progress in a new vibration. ‘Thus if the body be at H,
the fractional part of 2<¢ will be the are AG, and this will have the same ratio
to the entire circle which the time of describing the. portion of path, AH, has
to the total time of double vibration.

Let us now suppose that the second impulse (still normal to the first) is not
equal to the first, but greater or smaller ; and that the vibration which it would
independently produce has an amplitude (measured from the centre) represented
by a’. The figure of the orbit will, in this case, be an ellipse, with the greater
or lesser axis in the direction of the original vibration, according as.a is ereater
or less than a’. The velocities in the direction of @ will still, as before, be
represented by asin2zt, while those in the direction of a’ will be represented
by a'cos2zt; and these expressions will also stand: for the ordinates of the
orbit, y and x. 2z¢ here takes the place of the former symbol, ¢.

150 UNDULATORY THEORY OF LIGHT.

Let us now suppose that the second impulse, though still normal to the first,
is not imparted either at the limit or in the middle of its path, but at a point
corresponding to 2z¢, where ¢ may have any value whatsoever. The velocity
of the body at the time ¢ will be qsin2zt. The velocity produced by the
second impulse necessarily commences with the maximum:—, that is, with the

5 : : 1 : au :
velocity belonging to the time = and hence is a’.sing z, or a’.sin90°.

Then the difference of the two, in respect to phase—that is, to the degree of
their advancement in their respective vibrations—will be 2z¢—90°, or 90°—2z¢;
which, for convenience, put equal to 0. After a further time ¢’, the two veloc-
ities will be—

1. a. sin(27t-+2z7t')—=a. sin(90°L0+ 2zt')—=a. cos(2zt! 4 0)—=y.

2. a’. sin(90° 4+ 2z¢') =a’. cos2zt' =a.

Expanding y, and eliminating 272’, there results the equation,

ay + a&x?—2aa'xy.cosd =a?a' sind, [1.]

This is the general equation of the ellipse referred to its centre. It follows,
therefore, that any two impulses, applied in directions at right angles to each
other to a body susceptible of vibration, will cause the body to describe an ellip-
tical orbit, whatever be the interval between the impulses.

If, however, we suppose the second impulse to be in the direction of the orig- —
inal vibration, and not at right angles to it; and, as before, that there is a differ-
ence of time corresponding to the are 0, then the body will be impelled by two
conspiring or conflicting forces, capable of producing the simultancous velocities,
a sing, and@ sin(g+0).

Let us put (a+a’cos0)?+ (a’sind)?’= A’.

(a+a'cosd)? (a’sin@)?
Se oe
the symbol w denoting a determinate angle. Then,

Or,

=1—cos*w+sin2w.

a+a'cos0—=Acosw; and a! sin0d= Asinw,

Let the first of these equations be multiplied by sing, and the second by
cos¢: their sum, added member for member, will be—
a sing-+a’ sing cos0-+a’ cosg sind=A sing cosw+A cos¢ sinw.
Or, a sing+qa’ sin(g+0)=A sin(g+e). [2.]
The first member of this equation is the expression for the velocity which the
body will possess at any time answering to ¢, after the commencement of the
vibration a, which is least advanced in phase, and the second member shows
that this velocity is that which would exist in the body at the same time, had it
been acted on by one impulse only, capable of imparting the velocity A, and
applied at a moment earlier than @ by the time corresponding to o, and later
than a’, by the time corresponding to 0—w.
The value of the velocity A, in terms of the original velocities @ and a’, may
be obtained by developing the assumed equation above, when it takes the form,

A? =—a?+a?+2aa'cosd; or, A-L V @ +a? + 2aa'cosd. [3.[
This expression is remarkable, as being the value of the diagonal of a par-
allelogram, of which the sides are @ and a’, and the

A £B angle of their inclination 0. In the figure annexed,
i\ let AB == DC—<a, and AD = BC =a’. Also let BCD
Ean 2) —=ADE=—0. AE being drawn perpendicular to CD
LD Co produced, we have DE=a’cosd, and AH—a'siné.

Fig. 30. Then,

UNDULATION. 151

AC? =EC?+ AB?=(DC+ED)?+ AE? = (a+ a'cos0)?+ (a'sin0??= A?.
Also, AER —a'sing—A.smACD. And CE—a-+a’/cosO=A.cosACD.

Therefore, ACD—a», or the angle between the diagonal and the side denoting
the force corresponding to the component which is least advanced in phase, is the
measure of the interval of time between that component and the resultant, or the
time earlier than a, at which A must be applied in order to produce alone pre-
cisely the same succession of vibrations in phase and in force which is produced
by the combined action of @ and a’.

If the second impulse be oblique to the first, it may be decomposed into two
components, one acting in the direction of a, and the other at right angles to a.
The effects of these may be successively estimated according to the principles
already illustrated. And the same principles may be applied to the determina-
tion of the resultant of any number of impulses, acting in all possible directions.
The important conclusion is that, though the form of the path and the ampli-
tude of the oscillations of the body may be altered, yet they are, in all cases,
eapable of determination, and the time of the vibration will be invariable.

§ II. UNDULATION.

Hitherto we have supposed that the vibrating body imparts none of its motion
to surrounding bodies. This is a ease which can fever be experimentally real-
ized, and, if it could, it is not the case which concerns us at’ present. We wish
to show the connexion between eibration and undulation, and, to this end, we
must suppose the body in vibration to be immersed in an elastic fluid, whose
particles are set in motion by it- Such a fluid is the atmosphere; and it is mat-
ter of common knowledge that sound is an effect of undulations produced in the
air by vibrating bodies. It is also well known that sound does not attend all
movements in the air, not even all movements of vibration. A certain rapidity
is required, for a reason which will presently appear.

An elastic fluid may be described as one whose particles tend to recede from
each other, or have the same mechanical relations as if they possessed the
property of mutual repulsion. The distances between the particles, in the case
of such elastic fluids as actually exist, are probably very great compared with
the magnitude of the particles themselves. When the fluid is at rest, each par-
ticle is held in equilibrium by the repulsions of its neighbors. Ifa slow move-
ment be excited among these particles, they will not, to any material degree,
alter their distances from each other; but, if any one particle, or any stratum of
particles, be driven toward those adjacent, with such suddenness that the imertia
of the latter is brought sensibly into play, then the distances will be momenta-
rily diminished, or there will occur a local compression of the fluid at that place.
This impulse, it is evident, must come from some body foreign to the fluid, for
by the definition it must appear that the fluid is incapable of unequally com-
pressing itself. Suppose, then, the compressing body, after making its sudden
advance, to stop with equal suddenness. The repelling force between the first
and second strata will exceed that between the second and third; but the first
stratum cannot recede on account of the obstacle. ‘Che second, therefore, will
advance, diminishing its distance from the third, and so calling a greater repul-
sive force into activity between those strata also. ‘The third will then advance,
then the fourth, then the fifth, and so on. It thus appears that the movement
originally communicated to the first stratum will pass from stratum to stratum
through the whole fluid. Each stratum, moreover, will come to a state of per-
manent rest the instant the next has taken up the movement. This is in accord-
ance with the well known law of impact of equal elastic bodies. There is,
therefore, no wbration in this ease. But the progress of the movement is wnd-
form throughout the medium, and the velocity of transmission is the same, (or

152 UNDULATORY THEORY OF LIGHT.

sensibly so,) whether the molecular movement be large or small. This last fact
we learn experimentally, though it may be deduced from considerations entirely
theoretical, as will presently be shown.

A molecular movement, like what has just been described, may be called a
tremor. A succession of tremors, swelling and sinking in magnitude, each so
excessively brief that their successive differences are comparatively null, consti-
tutes an wndulation. Such a succession of tremors must be produced in the air
by a vibrating sonorous body. ‘Take, for instance, one of the steel springs of a
musical box. It traverses, in its vibration, but a very minute portion of space,
and its duration occupies an equally minute portion of time. But as, at the end
of its path, its velocity is, for an instant, zero, while, in the middle, it is very
great, we know, from the general principles laid down above, that, at interme-
diate points, it must have as many intermediate values as it is possible to imagine
points, and we are able, moreover, to give a definite mathematical expression to
those values. These various velocities, beginning and ending with zero, and
passing through an intermediate maximum, will be successively imparted to the
stratum of particles of air which is in contact with the spring. rom this stra-
tum they will be transferred to the second, from the second to the third, and
so on.

And here, to the clear understanding of this subject, it is necessary to take
into consideration a very important fact, viz., that, however rapid may be the
motion of the spring, the trefnors which the air takes up from it advance with a
velocity vastly greater. Let us suppose, for instance, that the spring makes a
thousand simple vibrations, or five hundred double vibrations, in a second, which
is somewhat below the number corresponding to the tenor C, and that the
amplitude of each vibration, measured between the extreme limits of its excur-
sions in both directions from the position of equilibrium, is one twentieth of an
inch. In one second after beginning to vibrate it will have described only fifty
inches, but in the mean time the tremor generated by its first movement will
have passed over eleven hundred and thirty feet. In this case, accordingly, the
tremor will have more than two hundred and seventy times the mean velocity
of the vibration. Thus, while the spring is advancing from its first zero of
velocity to its maximum, a distance of one-forticth of an inch, the first and
feeblest tremor which it excited will have reached a point nearly seven inches
in advance .of it, and the stratum next before it will be receiving the most ener-
getic tremor which it is capable of imparting. When it reaches the second
zero the first tremor will be fourteen inches in advance, the middle or maximum
will be seven inches in advance, and the stratum next it will have just received
a minimum impulse corresponding to the first. Were the spring to remain in
this position, the undulation would pass on, leaving the air in its vicinity at rest.
But as it instantly commences its return, it withdraws from the stratum in con-
tact with it the support it afforded against the repulsive forces of the more ad-
vanced particles ; and accordingly that stratum follows the spring, producing a
rarefaction, or increase of distance, between the first and second. 'The repellent
forces between the first and second strata will thus be diminished, so that those
between the second and third will predominate. The second stratum will con-
sequently follow the first, and in like manner each successive stratum throughout
the fluid will successively move backward toward the one before it; or a tremor
will affect every stratum of particles, as in the case before considere d, but will
differ from that in this particular, viz: that, in the latter case, the particles are
moving in one direction, while the tremor is advancing in the contrary direction,
whereas in the case we first considered the movement of the particles is the
same in direction with that of the progress of the tremor.

It is easily seen that the whole series of tremors produced by the return
Vibration will generate an undulation equal in length to the former, and differing
from it only in the direction of movement of the particles. This is called the

~

UNDULATION. | 153

wave by rarefaction; the former, the wave by condensation. The two are com-
plementary to each other, and both are to be understood as included when in
optics we speak of ‘an undulation.”

A visible illustration of the relation between vibration and undulation, which
we have been endeavoring, in what precedes, to explain, may serve a useful
purpose in facilitating the formation of correct conceptions. Let AB represent

Fig. 31.

the range of movement of a vibrating body, C being the centre of force and
the position of equilibrium. Upon AB describe the circle ADBE. Divide
the semi-circumference A D B into any convenient number of equal parts,
say eight, and from the points of division drop perpendiculars upon AB. ‘Take
AA/ equal to the entire length of a wave, and bisect it at b’. Divide AB’
and B’A/ each into eight equal parts. From the points so found draw per-
pendiculars, upward on B/A’, and downward on AB’. Cut off these perpen-
diculars to equality with those before drawn in the circle, in reversed order for
A’B/, and in the same order for AD’, and through their extremities, as thus
determined, draw the curve AL’B/D'A’. The ordinates to this curve will
represent the velocities of the molecular movements which will be in activity
along the line AB‘A’, at the end of one complete double vibration of the excit-
ing body in AB. ; . s

The point in which this illustration fails to convey a correct impression is in
the immense exaggeration of the extent of the range AB, of the vibrating
body, as compared with AA’, the length of the undulation. In sonorous
undulations this latter usually exceeds AB some hundreds of times. Of course,
no figure which could be introduced here could preserve these proportions
without making AB imperceptible.

Let us now return for a momenf to the assumption, which, as we have said,
experiment, in the case of sound, confirms, that the velocity of waye propaga-
tion will be uniform. This assumption, antecedently to any experiment on the
subject, might be justified by the consideration that each successive molecule,
or stratum of molecules, commences its motion under preciscly the same cir-
cumstances as those of the molecules before it; taken along with the ascertained
fact that the forces of recoil of elastic bodies in general are proportional to the
extent of disturbance. ‘There is no circumstance which could make the time
occupied by one stratum of particles in transmitting the movement to the next,
longer or shorter than that similarly occupied by any other; unless it should
be the decreasing amplitude of the molecular excursions, as, in the expanding
wave, the motion is divided among a greater number of particles; and this cir-
cumstance, under the observed law of elastic force just stated, can have no effect
upon the time of completing the oscillation.

But the proposition admits of a more direct and not a diflicult proof. If AB
CDEF be a tube containing an elastic fluid—say air—open at CD, but with a

AA’ Pb oe movable piston at AI closing the tube completely;
ae =a and if, in a very minute portion of time, 7, this piston
| |

be advanced from AF te A/F’, propagating a tremor

A ‘ | which just reaches BE when AJ reaches A’, then,
Fr w@ E & WD for the instant, the fluid between A’/L’ and BE will
Fig. 32. be more dense than before, in the same ratio as its

volume is less, or (the diameter of the tube being constant) in the ratio of AB

154 UNDULATORY THEORY OF LIGHT.

to A’B. Let the natural elasticity of the air be called e. By this natural
elasticity we mean that force with which the air would tend to expand into a
vacuum, or crush in the sides of a vessel from the interior of which the air has
been removed. It is measured by the weight upon a square inch, of the column
of mercury required to balance it, and this is compared with gravity by con-
sidering that it would move a body of a unit in bulk and density (say a cubic
inch of water) as much faster than gravity alone, as it is greater than the weight
of such a unit. If, then, g represent the velocity which gravity can impart in
a second, if 4 be put for the height of the barometric column, and if D stand
for the density of the mercury in the column,

e=ohD.

Employing e’ to denote the increased elasticity of the compressed air between
A’'T’ and BE, and putting AB=a, A'B=a', and AA'=2", we have

; xv ; gl!
e'==e—5 eee ae,
x x

This difference, e’—e, is the effective force by which BE is acted upon; for
the space between BE and CD is filled with uncompressed air, which opposes
the movement of BE by the force e, while the compressed air between A'F’
and Bi urges it with the force e. Now, the velocity of movement imparted to
a body by a given force ix dependent not on the time and force only, but also
on the mass to be moved. And it will evidently make no difference in the
rapidity of propagation of movement, whether—mass remaining the same—we
suppose BE to be the stratum of molecules which is nearest to “AP , or whether
we suppose it to be the middle stratum of a number filling the space half way
between it and AF on the one hand, and CD on the other. In either case
there will always be the same mass (m) which will be proportional to the length
of the column a, and its density, which we may represent by d:—or m will
always be as xxXd. Now the velocity v. which any foree (as e'—e) will gene
rate in the minute time ¢ in this mass, will be

e’'—e*

—— t;
m

or, substituting the values of e’—e and m,

ex''t
== 6
. wad
And the velocity of wave-propagation (which may be denoted by V) multi-
plied into the time ¢, will give a, the distance the tremor has advanced in that
time; or e—Vé. Moreover, since x” is the distance moved by the molecules
in the time ¢, it must have the same ratio to x, or to 2’, (for the ditierence is so
slight as not sensibly to affect the ratio) that v has to V.

Hence,

Vv
Va

Substituting these values, we have

evt 7
V= ayy24? OF V7 and “V = [4.]

But e and d are constants. Hence the velocity of the wave is uniform. *

In this demonstration it has been tacitly assumed that the expansive force of
a confined body of elastic fluid is inversely proportional to its bulk. This is
called the law of Mariotte; and it is true if the temperature of the fluid, when

UNDULATION—DISPERSION. 155

in a state of dilatation, is the same as when it is compressed. But compression
developes heat, and the expansive force increases directly as the temperature.
On this account it is necessary to introduce into the expression for the value of
V another constant, which is the quotient which arises from dividing the capacity
of air for heat when it is expanded under a constant pressure, by its capacity
when its pressure is raised under a constant volume. ‘hese capacities being
represented by c¢’ and ¢, the velocity becomes

ec!
de’

in which all the factors are still constant, and the velocity is uniform.

It will be further observed that the demonstration is independent of the am-
plitude of the vibration, and also of the length of the wave. The distance AA‘
has no necessary relation to either the one or the other of those dimensions.
The waves will be longer as the ¢2me occupied in a vibration is greater, and
shorter as the time is less; but this will be only because, in the first case, a
larger number of tremors by condensation occur, before the tremors by rarefac-
tion commence, than in the second. These tremors, in longer and shorter waves,
are arranged in larger or smaller groups, but every tremor, of whichever species,
advances with the same velocity.

Observation proves that in sonorous waves this theoretic influence is true.
In the range of musical tones, the waves corresponding to the deepest notes are
two or three hundred times longer than those belonging to the highest; yet at
any distance at which music is audible all the notes of a melody come to the
ear without the slightest perceptible disturbance of their order.

As we shall presently have to apply the undulatory theory to the explana-
tion of optical phenomena, this seems to be the proper place to anticipate an
objection which has been made to such an application of it, founded upon this
presumed constancy of velocity of propagation for waves of all lengths. The
dispersion of light by refraction, or the separation of the elementary components
of light by the prism, must, upon any theory, be regarded as irrefutable evi-
dence that the velocities of these components are unequal.* If the undulatory
theory be the true one, it is demonstrable that the undulations of the more re-
frangible rays are shorter than those of the less refrangible; and it is also neces-
sary, on that theory, to admit that in point of fact the velocities of the same
rays are less. ‘This fact so directly conflicts with the proposition just now
demonstrated, that for a long time it was regarded, and by some continues still
to be regarded, as an almost insuperable objection to the wave theory of light.
If we refer once more, however, to the demonstration, we shall see that it
involves one assumption which is not strictly truace—the assumption that AA’ is
too insignificant a quantity to be regarded when subtracted from AB, and in
therefore making AB=A'B. In the case of acoustic waves this assumption
is admissible, and observation proves that it introduces no sensible error; but
if the wave theory of light be the true one, the undulations themselves must be
excessively minute; so that it is not only quite possible, but even probable, that
the amplitude of the molecular excursions may have a very sensible ratio to the
undulation length. Observe, however, that the admission of this supposition
does not draw after it the consequence that the velocity of wave propagation

“must, as a necessity, vary with the varying lengths of the waves; it only viti-
ates our previous demonstration that this velocity is constant for waves of all
lengths. ‘The same constancy may continue to exist, but we must establish the
truth, if it is one, by different methods of proof. It is even possible that it may
exist under certain circumstances—that is, in certain media, and not in others.
This last is the conclusion which was reached by Mr. Cauchy after an examina-

v=

On
pase)

* This must at least be true after refraction if not betore.

156 UNDULATORY THEORY OF LIGHT.

tion of the question in its most general form. If we put 2 for the wave length
and ¢ for the time of vibration, aad assume—

27 27

? ae

ae ey between these quantities is found by him to be expressed by the
ormula—

k=

Sa, kh? + agk*+ agk®+ ako + &e.

in which the constants 1, a2, a3, &c., are the same for all rays in the same
medium, but differ for different media.

Now the velocity of every uniform movement is expressed by dividing the
space passed over in any given time by the time of passing, and assuming a
wave length for the space, and V for the velocity—

aa s s

s
=] Hence, A=, and P= 73,

and, by substitution,
Va, ~b dak? +} ask +. &e.

The velocity in the same medium is therefore a function of the length of the
wave. But if, in any medium, the coeflicients of the terms beyond the first are
insensible, the equation will become V?—=ay, or the velocity will be constant for
all the rays. ‘This he supposes to be true in a vacuum and in media which,
like the air, do not sensibly disperse the light. *

By reverting the first series it becomes—

A s?-+ Aost+ Ass®+- &e.,

which is convergent like the first, and in which all the terms after the first three
may be neglected.

s . eee ;
yp if the velocity in vacuo be put equal to unity, we shall have,
Osa : °
by substitution and reduction,
1 [6.]

i e 2—A,-+ Ags? +As 584,
V

in which » is put for the index of refraction. This index is therefore a function
of the time of vibration in vacuo, which time is necessarily unaltered by refrac-
tion; since the period in the second medium is determined by the period of the
impulses, which impulses are the vibrations in the first. But the time of vibra-
tion in vacuo is inversely as the length of the wave. Hence, if we determine
by observation three wave lengths in vacuo, and three Gonres panting indexes of
refraction, we shall have the data for determining the three unknown constants,
Aj, Ag, and A;. For all other wave lengths the indexes may then be computed.

T’bese theoretic conelusions can only be thoroughly tested by comparing the
values deduced from the formula with the results of observation upon media of
high dispersive powers. A very elaborate series of such comparisons was made
by Prof. Baden Powell, which exhibits a general agreement between the com-
puted and observed values quite within the limits of the probable errors of ob-
servation. We are therefore justified in saying that the different velocities of
propagation of luminous undulations of different. le ngths no longer constitute a
serious objection to the undulatory theory. :

Jt will now be easily seen that so long as the movements of the vibrating

UNDULATION —PRINCIPLE OF HUYGHENS. 157

body continue, undulations will continue to flow off from’it through the air; but
that the moment they cease, the undulations will cease also. Also that during
the existence of any undulation there are actually and simultancously existing,
somewhere im its length, all the various velocities, positive and negative, which
belong successively, ‘and one at a time, to the v ibrating body. Also that, as the
progress of the undulation is uniform, its fractional parts are proportional in
length to the times of performing them; and finally that the molecular velocity
at any point may be represe ted by observi ing to what fractional part of a whole
undulation that point corresponds, and taking the sine of the same fraction of
an entire circle multiplied by the maximum velocity.

It must not be understood, because, in what has been said, mention has only
been made of tremors in the direction of the original vibration, that therefore
undulations are confined to that direction. It is impossible to disturb the equi-
librium of the molecules of an elastic fluid, at any point or in any direction
whatever, without disturbing that of all the adjacent molecules, and giving rise
to tremors in all directions. Ata distance from the vibrating body which is
considerable compared with the size of the body, therefore, the front of the
wave will be sensibly spherical, and when the body is small it may be regarded
as strictly so.

Tt is furthermore manifest that the molecular movements need not be, as we
have hitherto supposed them, /inear, nor directed to and from the centre of the
wave. As they may be derived from any of the forms of vibration which
have been described, they may be circular or elliptical; and they may be
performed in the tangent plane of the wave itself; instead along its radius.
In the ease of circular movements performed around the radius as an axis,
an undulation will then consist of a chain of particles occupying positions
less and less advanced, in the direction of progress, in their respective circles,
until the last differs from the first by 360°. At any instant, therefore, the par-
ticles in such undulations, or series of undulations, will present the exact counter-
part, direct or reversed, of the thread of a screw.

At avery great distance from the centre of disturbance the curved front of
the wave will become sensibly plane. If a solid obstruction be placed in the
way of such a plane wave, having in it a small aperture through which a minute
elementary portion of the movement may be propagated, while all the remain-
ing part is arrested, then this aperture will become the centre of a new spherical
wave on the other side of the obstruction. If the solid be perforated by a great
number of apertures, each of these will generate its own independent wave;
and all these waves, as, in their progress, they encounter each other and become
blended, will ultimately reproduce anew the plane wave from which they origi-

nated. By supposing the number of these apertures infinitely great, and the
spaces between them infinitely small, we shall arrive at the conclusion that a plane
wave is equivalent to an infinite number of spherical waves, whose centres are
infinitely near to cach ocher im that plane, and of which the plane wave is the
resultant; so that if, at any time, we intercept any number of these component
waves, either such as are contiguous to each other, or such as are separated by
determinate intervals, the consequences of the proceeding may be calculated a
priori by finding the resultant of those which remain unobstructed. This princi-
ple, which is of the highest importance to the physical theory of undulation as
applied to optics, was first laid down by Huyghens. We shall presently see
how it was applied by him to explain the phenomena of the reflection and re-
fraction of light.

§ 3. REFLECTION AND REFRACTION.

If light is to be regarded as an effect of undulation, the elastic fluid in
which its undulations are propagated must be inconceivably more rare than the
air. ‘This fluid must be supposed not only to fill all space, but also to occupy

158 UNDULATORY THEORY OF LIGHT.

all the intervals which separate the particles of ponderable bodies; as well of
those which are opaque as of those which are transparent. It is furthermore
necessary to suppose that within these bodies it is possessed of a density or of
an elasticity different from that which belongs to it in free space ; or that the
molecules of the bodies themselves, in some manner, retard its movements
among them. Assuming for the preseut the first of these suppositions to be
the true one, it will follow that when a luminous wave encounters the surface of
a ponderable medium, its velocity of progress must undergo a change. The
nature of the change may be best understood by referring once more to the laws
which govern the impact of elastic solids. If a non-elastic ball impinge upon
another equal to it at rest in the line which joins their centres, it will divide
with the latter its motion, and the two will go on together with half the origi-
nal velocity of the first. But if the balls are elastic they will be in a state of
compression at the instant in which the motion is equally divided, and the re-
coil from this compression, acting with a force equal to that of the impact
which produced it, will destroy the remaining half of the velocity of the first,
and communicate an equal addition to the velocity of the second, so that the
latter will proceed with the entire velocity which belonged to the impinging
ball, and this will remain at rest. But if the impinging ball be heavier or
lighter than the other, the motion will not be equally divided at the moment
nen the impact brings them to a common velocity—that is to say, at the mo-
ment when, if non-el: astic, they would begin to move together ; and the recoil,
which doubles the effect of impact, will destroy less or more than the entire
motion of the first and will add an equal amount to the motion of the second.
If less than the entire motion of the first is destroyed, that body will continue
to advance; if more, it will move ina contrary direction, or rebound. If the
second, at the oes of maximum compression, has received less than half
the motion of the impinging body, (in which case it is the lighter of the two,)
the joint velocity with which both tend to advance together will be greater than
half the original velocity; and as this will be doubled for the body originally
at rest, by the recoil, the second body wiil go on with a velocity greater than
that of the impinging body. But if the second in the collision receives more
than half the motion of the impinging body, (in which case it will be the heavier,)
the joint velocity will be less than half the original velocity, and accordingly
the final velocity of the second will not be so great as that with which the first
encountered it.

Regarding the successive strata of the ether in a luminous wave as elastic
Bodies, it will follow that so long as they are equal in mass (which will be the
case when the density is uniform) the passage of an undulation or tremor will
leave all the ether behind it at rest. But if, at any given point, a stratum of
greater mass (that is, an ether of different density) ‘be encountered, there will
be a movement of return as well as a movement of advance; that is to say, there

will be a reflected undulation which, in the view we are now taking, will be an
undulation by condensation. If the change of density be from denser to rarer,
then the advance movement of the impinging tremor will not be entirely arrested,
and there will be a reflected undulation by rarefaction. We have here sup-
posed the impinging wave to be in that phase in which the molecules are mov-
ing in the same direction as the wave itself. Lut the consequences will be
entirely analogous if we suppose it to be in the opposite phase: only that, on
that supposition, the phases of the reflected waves will also be the reverse of
what is stated above.

It appears, therefore, that at any surface at which the luminiferous ether
undergoes a change of density, an impinging wave will, in general, be divided
into two parts, one of which will be propagated beyond the surface, while the
other will be reflected from it. It remains to be considered what. should be the
laws governing the directions in which these two waves will proceed.

REFLECTION AND REFRACTION. 159

For this purpose let us assume a
plane surface, as MN, bounding a trans-
parent medium more dense than air.
Let AA’ be the point of a plane wave
advancing in the direction PA, P’A’,

nand passing from the air into the medi-
um between the points A and B. We
have seen that this wave will be par-
tially reflected from AB. In order to
determine the front of the reflected
wave let us suppose, according to the
Pig. 33. principle of Huyghens, that every point
of the surface of AB is the origin of a new spherical wave propagated in every
direction from that point. It will be sufficient for the illustration to attend to
a few only of these poiuts, as, for instance, A, C, and B:—C being taken half
way between the other two. By hypothesis AA’ is perpendicular to PA.
Draw CA” parallel to PA. The velocity of the reflected wave being equal to
that of the incident, when the wave front AA’ reaches the position Cd, the ele-
mentary reflected wave from A will have travelled to a distance equal to CA.”
When’ A’ reaches B the reflected wave from A will have reached a distance
AB’ equal to A’B. Also, at the same instant, the elementary wave from C will
have travelled a distance CB” equal to 6B—=A’'S. With A and C as centres de-
scribe the small circular ares shown at B’ and B”, and from B draw BB’ tangent
to the first of these ares. It will also be tangent to the second. For if AB’Q’
be drawn from A through the point of contact B’, and CB’Q” parallel to
it, then, because AB is bisected in C, CB” is half of A B'; and it is also
perpendicular to B’B, consequently B’ is a point in the spherical wave front
which originates from C. And as similar reasoning may be applied to all the
elementary waves reflected from the points between A and B, it follows that
the tangent BB’ is the resultant reflected wave front moving in the direction
AQ’ or BQ. Also, from the similarity of the triangles AA’B and ABB, it
is evident that the inclination of the wave front AA’, or of the ray PA to the
reflecting surface MN, is equal to that of the wave front BB’, or of the ray
BQ to the same surface. The incident and reflected rays are therefore equally
inclined also to the zormal to the surface: or, in other words, the angle of re-
flection is equal to the angle of incidence.

If we turn our attention to that portion of the incident wave which is propa-
gated into the medium beyond the surface, the construction which determines
the refracted wave front is analogous to the foregoing. Only, in the second
medium, as it is the denser of the two, the velocity of ‘propagation will be
diminished. Suppose it to be so in the ratio of » to 1, the circles described
from A and C must have their radii, AB’/” and Ce reduced below A'B, and
6B in the same proportion.* The wave front of the refracted wave will then
be the common tangent BB!” of these circles. Also, if we observe that A’B=—=

AB sin. A'AB, and AB!’ = AB sin. B’” BA, we shall obtain the proportion,
sin A’/AB: sin B’’BA:: A'/B: AB” :: 2: 1.

But these angles, being the inclinations of the wave fronts to the refracting
surface, are also the inclinations of the rays themselves to the zormal to the

* A diminished velocity might be a consequence of a change in the time of a vibration
without a corresponding change in the undulation length; or it might be caused by a change
af both. But, in the case in hand, we are not at liberty to assume any change in the time
of the vibration, because the impulses which produce the molecular movements in the second
medium are the vibrations themselves of the first. The undulations in the two media are,
therefore, isochronous; and it is only possible to explain the difference of velocity of undula-
tion progress by supposing a change of undulation length.

160 UNDULATORY THEORY OF LIGHT.

surface; that is, they are the angles of incidence and refraction. The law of
Snellius is thus very simply deduced from the theory of undulation. It also
appears from the foregoing proportion that the velocity before refraction. is to
the velocity after remachen as the sine of incidence is to the sine of refraction,
or as the index of refraction is to' unity.

It was not until after Huyghens had perfected his theory of refraction, that
he became acquainted with the remarkable case of Ieeland spar. In order to
reconcile the phenomena presented. by this crystal with his theory, it was
necessary to suppose that the incident wave is divided at the refracting eae
into ¢wo waves having unequal velocities. But, inasmuch as one of these wave
must, on this hy pothesis, and, in order to meet the phenomena, have a eit
greater in some directions than in others, it occurred to him that the second
wave must probably be spheroidal, and not spherical. Following out this in-
genious idea, he presently discovered that it contained a pertect explanation of
all the apparent anomalies of double refraction; and by generalizing the
method which has just been given for finding the direction of a ray after re-
fraction, and extending it to embrace spheroidal as well as spherical wave
surfaces, he contrived a geometrical construction by which the path of the ex-
traordinary as well as of the ordinary ray may, in all cases, be exactly deter-
mined.

In order to understand this, let it be observed that the greatest and least
axes of the spheroidal wave will evidently be proportioned to the greatest and
least velocities of the ray in the erystal; and these velocities are inversely as
the corresponding indexes of refraction. Also, as the least index, in the case
of Iceland spar, is that which is found in the plane perpendicular to the optic
axis, and as the refraction is there conformable to the law of Snellius, it is
manifest that this is the plane of greatest velocity, and is the equatorial plane
of the spheroid. The polar axis of the wave corresponds in direction, therefore,
with the optic axis of the crystal. Let it also be remembered that the least
velocity of the extraordinary ray is the constant velocity of the ordinary ray ;
or is, in other words, the radius of the spherical wave.

If, now, a plane wave of light fall obliquely upon the surface of a crystal of
Iceland spar, intersecting it in a straight line, any point of this line of inter-
section may be assumed as the common centre of a spherical and a spheroidal
wave, having one diameter in common, parallel to’the optic axis of the erystal,
which common diameter is the axis of revolution of the spheroid. Moreover,
as this supposition may be made of every other imaginable point of the line of
intersection, it follows that there will be an infinite number of elementary
waves, spherical and spheroidal, simultaneously generated. As the incident
wave advances, the line of intersection will advance along the surface of the
crystal; and in every position of this line a new set of elementary waves will
in like manner originate. By reasoning similar to that which was employed in
the illustration of ordinary refraction, it may be shown that, in any position of
the incident wave, all the elementary spherical waves will be touched by one
and the same tangent plane; and all the elementary spheroidal waves will be
touched by one plane likewise. These two tangent planes must intersect each
other in the line in which the incident wave intersects, at the moment, the sur-
face of the crystal, or the plane of that surface; but they will not coincide ex-
cept in the single case in which the velocities of wave progress are equal; that
is to say, when the movement of progress within the crystal is in the direction
of the optic axis.

The geometrical problem of determining the path of the extraordinary ray
reduces itself, therefore, to this. With the point of incidence as a centre
deseribe a sphere. Upon that diameter of the sphere which coincides with the
optic axis deseribe a spheroid of revolution, whose revolving axis is to its fixed

DOUBLE REFRACTION. 161

axis as the greatest index of refraction is to the least. In the plane of inci-
dence lay down the path of the ordinary ray according to the law of Snellius.
Through the intersection of this path with the surface of the sphere pass a
plane tangent to the sphere; and through the intersection of this tangent plane
with the plane of the refracting surface pass another plane tangent to the
spheroid. The radius of the spheroid drawn to the point of contact will be the
path of the extraordinary ray.

The following is the construction usually given in this case. It has the
advantage of involving only the angle of incidence. Let the velocity before
refraction be represented by unity; and after refraction let the velocity of the
ordinary ray be v, and that of the extraordinary ray perpendicular to the optic
axis be wv’. With the point of incidence ‘as a centre let there be described a
sphere and a spheroid, as before, the radius of the sphere being =v, and the
revolving axis of the spheroid being v'. On the plane of the refracting sur-
face and in the plane of incidence take a distance (in the direction of progress)
equal to the cosecant of the angle of incidence, and through the point so de-
termined draw a perpendicular to the plane of incidence. The plane passing
through this perpendicular and touching the spheroid, determines the direction
of the extraordinary ray, which, as before, coincides with the radius to the
point of contact.

To illustrate by a comparatively simple case. In figure 34, let MN be the
surface of the crystal, and CD the direction of the optie axis. Let also the plane
of incidence (represented by the plane of the figure)
be a principal section. RC being the direction of
the ray and C the point of incidence, make RC =
unity, draw CG perpendicular to RC, and RG par-
allel to MN, cutting CGinG. Draw GQ parallel
to RC. Then GQ being made radius, QC is the
cosecant of (CG = PCR = the angle of incidence.
Then if, with the centre C, a sphere be described
whose radius is CD = v, and also a spheroid whose
polar radius is CD also, and whose equatorial radius is made = v’, the tangents
QE, QI’, drawn through Q to the sphere and spheroid respectively, will deter-
mine the directions of CK, CF, the ordinary and extraordinary rays.

The hypothesis of Huyghens completely determines the geometrical law of
double refraction, but it leaves the physical cause of the phenomenon unex-
plained. It is easy to understand how the disturbance at a single point of the
molecules of an ether of uniform density and elasticity should produce a spheri-
cal wave; and it is also easy to comprehend how a similar disturbance in an
ether of variable density or variable elasticity should produce a wave having
a surface not spherical; but, as undulation was understood in the time of
Huyghens, it was not easy to comprehend how waves of both these descriptions
should be generated in the same ether simultaneously. We have already seen
that Huyghcens himself was very greatly astonished to observe that, when the
two rays into which a single incident ray is divided by double refvaction in a
erystal of Icland spar, fall, after emergence, upon a second similar crystal, they
are, each of them, in some, and in fact, in most positions of this second erystal,
again divided, so as, of the single original ray, to make four; while in other
positions they are not so subdivided, but remain two only. But, in fact, this
new phenomenon presents no really new cause of astonishment. The thing
which ought to have surprised him, the point which involved, in truth, all the
difficulty of the conception, lay in the actual coexistence of dissimilar waves in
the same ether. No mode of explaining this fact could well have failed to ex-
plain the other at the same time.

It was only, however, after the entire inadequacy of any theory of light which

lls

Fig. 34.

162 UNDULATORY THEORY OF LIGHT.

had been suggested, to explain the multiplied and brilliant phenomena of polari-
zation and double refraction had been universally felt and acknowledged, that an
idea presented itself (and this simultaneously, or nearly so, to two distinguished
physicists) which contained within itself the key to the original and to all sue-
ceeding difficulties. In undulation, as understood by Huyghens, Newton, and
others, the molecular movements were supposed to be always in the direction of
wave-progress and the contrary. ‘Though this is the case with the atmospheric
undulations which produce sound, it was ingeniously suggested by Fresnel and
Young that it is probably not so with the ethereal undulations which produce
light. Polarized rays are differently affected to reflecting surfaces on their dif-
ferent sides. Suppose the movements of the molecules to be nurmal to the di-
rection of progress, and this fact is easily explained. And not only that, but a
whole class of perplexing, and praviously, in fact, entirely inexplicable phenom-
ena, to which we shall have presently to attend, are, by this simple supposition,
rendered, not merely intelligible, but so necessary consequences of the hypothe-
sis, that they might have been predicted (as some of them actually were) before
having been ever observed.

Though the idea of transverse vibrations occurred, as just remarked, to Young
as well as to Fresnel, it is, nevertheless, to Fresnel alone that the credit is due
of having made it the basis of a theory fully wrought out and est :blished, as well
upon the basis of a thorough mathematical analysis, as of an elaborate and ex-
tensive experimental verification. ‘To apply it at present to explain the possi-
ble coexistence of two independent waves of different curvature and different
progressive velocity, originating simultaneously from a common centre in a
doubly refracting medium, we have but to make the two assumptions follow-
ing, Viz:

1. ‘The molecular movements, being in both of the two waves at right angles
to the direction of progress, are performed in planes which are at right angles
to each other.

2. The elasticity of the ether which determines the velocity of a tremor is
not the same in all directions within the medium.

It will presently be more part.cularly shown in what manner those two as-
sumptions serve to explain all the phenomena which appeared so unaccountable
to Huyghens, as well as many others which were not known to him.

§1V. INTERFERENCE.

We will now proceed to apply briefly the theory of undulation to the expla-
nation of some of the phenomena which we have heretofore detailed without
accounting for. Many, or most of the phenomena depend on the mutual influ-
ence of different undulations conspiring or conflicting in consequence of the
superposition of one upon the other. A gross illustration often employed in
explaining this idea is to refer to the appearances presented by the intersecting
rings formed in water into which two pebbles have been thrown. The elevated
rings and their intervening depressions are undulations; the molecular move-
ments are vertical, while the undulation progress is horizontal. When the rings
intersect, the points where two ridges cross are doubly elevated; the points
where two hollows cross are doubly depressed; while the points in which a
ridge in one system crosses a hollow of the other are neither elevated nor de-
pressed. The term applied to this influence of one undulation upon another is
enterference.

PRINCIPLE OF INTERFERENCES. 163

The interferences of liquid
waves are finely illustrated in
the undulations of mereury con-
tained in a vessel of elliptical
figure. Ifa disturbance be pro-
duced at one of the focal points of
the ellipse, the circular waves pro-
ceeding from it will, by reflection
from the sides of the vessel, form
a second similar system having
for its centre the other focus. If
the corresponding points of in-
ferference be connected, they will
form, as the figure shows, two
sets of curves, elliptical and hy-
perb lic, having for their com-
mon foci the foci of the original
ellipse.

The interference of waves of
sound is often very perceptible. It is observed only in musical sounds because
it can only be observed in those whose undulations are continuous and uniform ;
and such sounds are musical. It is best observed when the waves are long—as
in the case of the grave tones of the heavier organ-pipes. The sinking and
swelling of the sound, called by musicians the deat, is owing to one of the inter-
fering waves being slightly longer or shorter than the other. In many r-peti-
tions this slight difference of length accumulates until it reaches half an undu-
lation, when, if the two waves originally conspired—that is, (to borrow again an
illustration from the water,) if their two crests were originally superposed—-th-y
will, after this difference has crept in, be in conflict; or the crest of one will fall
upon the hollow of the other. During this interval a sink’ng of the sound will
have been observed; but immediately after, as the difference of path goes on
increasing from a half to a whole undulation, the sound will swell again as the
two crests once more approach superposition. Weneed hardly remark that the
interference of waves of sound of perfectly equal length would not be pereepti-
ble to us; for, in that ease, the resultant sound would be a coastant. If we en-
deavor, by moving about while two bodies of precisely similar pitch are sound-
ing, to pass from the points of conspiring to those of conflicting undulation, we
shall not find it easy to detect these points for several reasons

In the first place, when the molecular movements are normal to the way
front, as in the ease of sound, there is no complete interference, or approach to
complete interference, except when the waves are tangential, or approximately
so, to each other; except, therefore, in or near the line of the centres, and except,
it may be added, when the distance between the centres is an exact number of
half undulations. Again, at the intersections of sonorous waves, whether the
molecular movements conspire or conflict, their resultant is never so great as the
sum, nor so small as the dsference of the two components. The difference of
intensity between the maxima and minima of sound in such cases will not be
striking, unless they succeed each other with brief intervening intervals of time,
as in the case of the beats.*

It is, however, by this second method that we detect the interferences of light,
and not at all by the first. That is to say, we discover these interferences by
moving the eye through the space where they exist, when the points of maxi-
mum and minimum brightness are easily observed ; or we let fall the interfering

* Mr. Despretz has succeeded in this rather difficult experiment of localizing the inter-
ferences of sound from two pipes in perfect unison,

164 UNDULATORY THEORY OF LIGHT.

rays upon a white surface, when the same points will become manifest by their
difference of illuminating power. The first method is best, especially if the eye
be assisted by a lens, but the second is that which was used by the earliest
observers.

We cannot detect the interferences of light by observing periodical maxima
and minima, like the beats in music, because of the almost inconceivable short-
ness of the undulations. But if the waves of light were as long as the waves
of sound, interferences might easily be made to manifest themselves, something
in the manner of the Senillation of the stars, though with a regularity ae
that phenomenon does not possess

Before proceeding now to a more ‘¢ particular inquiry into the laws of the inter-
ference of luminous waves, it is proper to make two or three preliminary ex-
planations. ‘The phenomena compel us to the assumption that the molecular
movements in these waves are normal to the direction of progress; that is, to
the direction of vision. In other words, they are in the plane of the wave itself,
and at right angles to the ray. If we suppose that all ethereal tremors have
this character, we must account for the fact by presuming that the ether is
nearly incompressible. If this is the case, the vibrations of the luminous body,
at its surface, may move /ateral/y the whole stratum of ethereal particles which
is most nearly in contact with it, though they produce little if any motion per-
pendicular to the surface.

If MN, for example, be the surface of the luminous body, A,A,A, &c., the
row of ethereal particles next it, A’,A’,A’, &c., the row beyond this, and so on,

the arrangement of these particles will, on the
rineiple of e uilibrium, be such that the dis-

8 ee i Bt J 5 ot oe eee of Laaneat particles shall be equal. If

cL Al V Diag AE
BEES 6 6 © the molecular vibrations of the surface MN are

AT AV Wh 4” Av” AY” <"
fP

e

Vet Eo, ©, % 9% 4 incapable of driving the particles A,A,A, &c.,
Dre r W directly outward toward the plane of A’,A’,A’,

Fig. 36. &c., on account of the very difficult compressi-
bility of the ether, they may, nevertheless,
move them all sideways in the direction AB. ILct the entire force of this
movement be represented by AB. Join AA’, and draw BC perpendicular to
it. The foree AB may be resolved into the two forees CB and AC, of which
the second is directed toward the centre of A’. This again may be resolved
into the two, AD and DO, of which the first is normal to MN, and, by hy-
pothesis, produces no sensible movemeut. But DC is parallel to MN, and, as
all the other particles in the stratum A’,A’, and are simultaneously acted upon
by similar forces, they will all move in the direction of DC, without changing
their distances from each other.

It is not necessary to suppose that the ether has absolutely no compressibility.
In fact, if it had none at all, it could have no elasticity ; or, what is, singularly
enough, practically the same thing, its elasticity would be infinite. But its
compressibility must be esteemed very slight, and its elasticity accordingly very
high, not merely because of the necessity of admitting lateral or transverse
vibrations, but because of the immense velocity of light. It is easy to see that,
if the ether were totally incompressible, the velocity of light (if in such cireum-
stances there could be any such thing as light) would be infinite; that is to say,
any movement in the ether, if it could be produced at all, must be produced
simultaneously through the whole extent of the ether. In proporticn as com
pression is easy, the rapidity of the propagation of a disturbance (density re-
maining the same) must be less. The immense velocity of light affords, therefor. ,
« strong ground for believing that the compressibility of the ether is very small.
Still, it is hardly conceivable that there should exist absolutely no molecular
movements normal to the wave at all; and, in fact, the existence of such vibra-

PHYSICAL THEORY OF POLARIZATION. 165

tions is now generally admitted, though they are usually assumed to be incapable
of impressing the organs of vision.

But while the molecular movements in luminous waves are assumed to be at
right angles to the direction of progress, or of the ray, there exists no natural
necessity to determine them in azimuth toward one direction rather than toward
another. It is accordingly capable of easy demonstration that ordinary light
has no determinate plane or azimuth of vibration, but that its successive undu-
lations assume every variety of azimuth. ‘There is no proof, however, that
changes of azimuth are incessant; in other words, that many undulations, in
fact, many thousands or perhaps millions, do not follow each other usually, in
the same azimuth, between the changes. This, indeed, is probable, since the
ethereal vibrations take their character from those of the luminous body, and
these may reasonably be presumed to have a certain persistence in their modes
of vibration, or at least not to undergo incessant and abrupt changes. Beyond
a certain limit, however, this persistency could not continue; nor could there,
among the changes which occur, be a predominating disposition to return to one
azimuth oftener than to another, or to remain in it longer, without imparting to
the light, more or less decidedly, the character of polarization. If five hundred
millions of the mean undulations of white light were to follow each other in a
single azimuth, they would occupy less than the millionth part of a second ;
and, accordingly, if five hundred millions of such undulations should take place
in each of a million different azimuths successively, the whole would be per-
formed in one second, and no instrumental test could detect polarization in the
aggregate beam.

The polarization of light consists, therefore, in the determination of all its
vibrations to a single plane. The effect of double refraction is to do this with
both the rays into which the incident common light is divided; and the effect
of reflection at certain definite angles, from certain bodies, as heretofore ex-
plained, is to do the same with the reflected ray.

Prof. Dove, of Berlin, has illustrated in a very ingenious manner the physical
relation of common to polarized light. A Nicol’s prism having been mounted
in such a manner as to admit ef being rapidly rotated about its axis, he trans-
mitted through it a ray of common light, which gave, of course, an emergent
polarized ray capable of traversing a crystal of Iccland spar (having its princi-
pal plane coincident with the plane of polarization) without double refraction.
On setting the prism into rotation double refraction instantly appeared, and the
ray was equally divided by the crystal in all azimuths.

When two polarized rays follow each other in the same path or intersect un-
der a very acute angle, it is obvious that, if their planes of polarization agree
in azimuth, they are in condition to interfere. If in phase of undulation they
are perfectly accordant, the two waves will be superposed, and the molecular
velocity of the resultant wave will be equal to the sum of the velocities of the
two components; but if there is a difference of phase between them amounting
to exactly half an undulation, then the crest of one wave will fall on the hollow
of the other, and the resultant molecular velocity will be equal to the difference
of velocities of the components. If the difference of phase is any other frac-
tion of an undulation, the circumstances of the resultant are determined by
precisely the same equation as that which has been given for the resultant mo-
tion of a vibrating solid, (equation [3],) in the same case. If a vibrating solid
derive its motion from two impulses which are not synchronous, we have seen
that its phases of vibration will be somewhere between those which the im-
pulses would have separately produced. Its actual vibration will therefore
produce an undulation or series of undulations, which will occupy the same
situation in space relatively to those which the separate impulses would have
produced, a8 the generating vibration occupies relatively to the component vi-
brations, in time. And it matters not to the result, whether we suppose two

166 UNDULATORY THEORY OF LIGHT.

component systems of undulations to be first generated by independent vibra-
tions and then combined; or suppose the two vibrations to be first combined,
and then to generate a single resultant system of undulations—the resultant
system is the same in both cases. On the first hypothesis, we allow two forces
to work out their effects separately and then unite the effects; on the second,
we unite the forces themselves, and make them unite their effects from the start.

Referring to the equation just cited, we see that the resultant molecular ve-
locity, when the movements are in the same plane, takes every value according
to the difference of phase of the components, from the sum to the difference of
the two component velocities. Thus, if @ be put — 0°, the equation

A— V@+a?+2aa’ cos0, will become A= Va?+a?+2aa'—=a+a’,
Orit @— a A — 20,
If 0—909, A= Va+a”; or, if aa’, A=aV2.
If 0—=180°, A= Va?+a?—2aa'—a—a’; or, if a—a', A—0.
i 660°. A— V +a +aa' ; or, if aa’, Aa V3.
Tt 0— 1267.4 Va +a”? —aa'; OY, fb -a——a ; Aa:

It may aid in obtaining clear conceptions of this subject to employ a graphic
illustration. Such notions are very desirable at this point of our progress, if
we would understand the application of the theory of undulation to the expla-
nation of optical phenomena; and especially of those of highest interest. In
the annexed figure, let the two curves PHA, QMN, represent two undula-
tions, whose molecular velocities are the ordinates drawn to the common axis,
MNAGC, and whose maxima velocities are PP’, QQ’. ‘The undulation PHA

is the more advanced in position; but, referred to any common intersecting
line as LA, the undulation QMN is the more advanced in phase.

Now we have seen that the resultant maximum molecular velocity, when
these undulations are combined, will be the diagonal of a parallelogram, of
which PP’ and QQ’ are the sides, and of which the angle of inclination of
the adjacent sides shall be equal to the difference of phase between the compo-
nents. Accordingly, from the point A, where the curve representing the undu-
lation least advanced in phase crosses the axis, measure off AC, in the direction
of progress, equal to QQ’, the maximum velocity of the wave most advanced
in phase. From ©, measure backward, CB, equal to PP’, the other compo-
nent maximum velocity. From the centre ©, with the radius CA, describe

INTERFERENCE—RESULTANT UNDULATIONS. 167

the circle AED, &c. At the point C lay off the angle DCA, equal to the
difference of phase of the two es thus :

Draw AL perpendicular to the axis at A. Upon this take AK, the devel-
opment of the semicercle AED, &c. Join KH, and draw Nd parallel to it.
Ad is the development of the are AED, which measures the angle DCA, the
difference of phase. For HA is to NA as a half undulation is to the difference
of phase:—that is, as a semocircumference is to the arc which measures the
difference of phase. But AK is a semicircumference, and Nd being parallel to
KH, we have.

HA: NA::KA: Ad: ACXz 3 are AED(—Ad.)

Join therefore CD, and complete the parallelogram CDGB, drawing the
diagonal CG. ‘Then from what has been before demonstrated, the angle ACE,
or the are AK, is the measure of the interval in phase between the resultant
and the component CB — PP’. The curve of that component crosses the axis
in A. Let, then, Ae be the development of AE, and draw eF parallel to KH.
F is the point at which the curve of the resultant undulation will cross the axis
in ascending. Making FS — AH, S is the point where the same curve crosses
in descending. And making SR’ = HP’, R’ is the point of maximum resultant
velocity. Draw R’R perpendicular to the axis, and make it equal to GC, the
diagonal of the parallelogram; R is the vertex of the r sultant curve. Any
other points of this curve may be found by taking the sums of the ordinates of
the two components. corresponding to the same absciss or point of the axis,
with like sigus when both components are above or both below the axis, and
with unlike signs when one is above and the other below, for the ordinates of
the resultant curve. The curve itself may then be drawn through the points
so determined.

This construction enables us visibly to verify the analytical results which
were just now presented. Let the radius, CD, revolve round the point C. the
parailelogram changing its figure as the revolution advances, and the variations
in the value of CG may easily be conceived.

Thus, when 6 = DA = 0°, the point D will fall upon CA, and the point
G upon BH. CB and BG will then be ina straight line, and CG will equal
CB+ BGO=a+a'. eee 6 = 90°, DCA and GBC are right angles,
and CG = VBvU? + BG, or, A= Va + a”. When 0 —1802, CD falls
on the axis to the right of C, and BG falls on BA. Hence, CG = a—a’.
In this case, if a = a’, coe = 0; or if equal waves differ in phase by half an
undulation they destroy each other. The two curves intersect the axis in the
same points, but the convexity of one of them corresponds in position to the
concavity of the other. Also, if equal waves differ in phase in any manner,
the crest of the resultant will fall half way between the crests of the two com-

nents.

When @ exceeds 180°, or the waves are more than half an undulation apart
the angle of the paraliclogram must still be measured from A through D round
to D’, and the inclination of the diagonal must be taken in the same way, from
A through ED and D’ round to KE’. These ares being developed on AL
produced, will give the position of the movable component and of the resultant
by drawing parallels to cut KH, as before. It will be seen in this case that, in
effect, the wave which we have regarded as the preceding wave becomes the
f,llowing wave, and vive versa; for if we consider the crests that nearest agree
in position as forming pairs, these pairs will be broken up by a discordance of
more than half an undulation, and new pairs will be fermed—the lagging crests
ceasing to agree with those crests of the other component which are before
them, and beginning to agree with those behind them. Hence, as the resultant
crest must fall between the two components of a pair, it in this case goes further

168 UNDULATORY THEORY OF LIGHT.

back than the wave which our construction makes the following wave. This
construction, therefore, embraces all possible cases.

But if the rays which are thus brought together are polarized in planes at
right angles to each other, then it will be manifest that the movements of neither
can interfere with those of the other; but, as in the case of the vibrating solid
again, they may produce a resultant of which the character may vary from a
plane vibration through every form of ellipse to a circle. Equation [1] ex-
presses the circumstances of this ease.

Thus, if, in that equation, we assume the difference of phase represented by
# to be 90°, cos 6 becomes 0, sin 61, and the equation is

Cy 4 Gan ae:
which is the equation of the ellipse when the axes of figure coincide with the axes
of co-ordinates. If we make a = a’, then we have
yy = ir a’,
which is the equation of the circle.
If the difference of phase is 0°, then
ay? — 2aa'zy + a?x? =0, or a'y —ax=0,
which is the equation of a straight line; and if @ once more be put =a’, z= y.
or the straight line makes equal angles with the directions of the original
molecular movements.

If the planes of the two undulations are neither normal to each other, nor co-
incident, there will be an interference which will be more or less complete, as
the inclination of the planes is less.

Rays of common light, if the difference of their paths be not very great, will
interfere, notwithstanding the fact that their undulations are confined to no
determinate azimuth. This fact proves, what has been above assumed, that the
changes of azimuth in common light cannot be incessant. But there is one con-
dition absolutely indispensable to produce interference in any case; it is that
the rays shall have a common origin.

If the light subjected to experiment be unpolarized, the necessity of the con-
dition is easily explained. The changes of the azimuth of vibration in two
such rays could not, except upon a supposition which has an infinity of chances
against it, take place at the same intervals and in the same order; and if they
did, the chances would be equally great against the coincidence of those planes.
It appears, however, to be true, as well of polarized rays as of common light,
that they will not interfere unless from the same origin. Weare obliged, there-
fore, to resort to the supposition, which has @ prieri, moreover, strong
probability in its favor, that there are irregularities at the very origin of the
undulations, or at the surface of the luminous body, which are propagated
with the undulations, and which will prevent the permanent coincidence or
conflict of two sets of undulations, unless both are equally affected by the same
irregularities. hus, if we observe the flame of a candle, we shall see that its
wavering motion will make the point of departure of the undulations it gene-
rates unsteady. But a difference of a single one hundred-thousandth part of
an inch in the position of the origin of two successive sets of undulations,
would put them into entirely opposite phases. Considering the activity and
the energy of the forces at work at the surfaces of incandescent bodies, it is
impossible to believe that the luminous waves which they generate can have
their origins absolutely invariable in position.

These things premised, we are prepared to apply the theory of undulation
to the explanation of all the phenomena of diffraction, polarization, and the
colors of thin or thick plates, in regard to which we have heretofore stated only
the facts. It is worth while, however, in the first place, to give a moment’s at-
tention to an experiment first suggested by Vresnel upon purely theoretic
grounds, and afterward made by him with complete success; in which the cir-
cumstances preclude the application of any of the special hypotheses which
had been previously conceived, for the purpose of accounting for the phenomena,

INTERFERENCE—FRESNEL’S MIRROR EXPERIMENT. 169

while the observed effects are consequences absolutely necessary of the undu-
latory theory.

Two mirrors, AB and AC, meet at a very
obtuse angle at A. JR is a minute radiant
point. The best radiant for this purpose is
the concentrated light from a small solar beam
introduced into a dark room and brought to a
focus by a lens of small focal distance. Rays
of light from R, reflected by the mirrors, pro-
ceed as from the points S and §/, which are
in the perpendiculars let fall from R on the
planes of the mirrors severally, and as far
behind them as I itself is before. If the mir-
rors AB and AC were in one and the same
plane, the points S and 8’ would coincide, or
there would be but one image of R formed by
the reflection; and the two images will be
nearer to each other, just in proportion as the
angle CAB approaches to two right angles.
The spherical waves proceeding from R as a
centre would be reflected from a single mirror in a system entirely similar to the
original one, proceeding apparently from the image behind the mirror. When
there are two mirrors and two such images, there will be two such systems of
spherical waves, which will intersect each other in ares more and more nearly
coincident, as the images which are their centres are nearer together. In the
figure there are drawn, with equal radii, from S and 8’, a succession of equidis-
tant circular ares, which may be considered to represent the crests of the suc-
cessive waves. The intermediate dotted ares may be taken for the hollows.
According to the principles already laid down there should be increased energy
of movement—that is an increase of brightness—wherever two ridges or two
hollows cross each other; and diminished movement, or a diminution of light
where a hollow crosses a ridge. And as it is obvious, on inspection, that the
intersections will be more widely separated from each other in proportion as the
centres are nearer to each other, it follows that these theoretically predicted
effects will be more conspicuous and more decided in proportion as the planes of
the two mirrors approach coincidence. If the light reflected from such a pair
of mirrors be received upon a screen, it will be obvious that, whatever be the
distance from 8 and 8’, there will be a point, as a, where the radii Sa and S/@
will be equal ; and as this will be true of all points in a line through @ parallel
to the intersection of the planes of the mirrors, there should here be a coincidence
of movements, and accordingly a bright stripe. At a little distance on each
side of this stripe there will be found parallel lines, in which the radius from
one of the centres will exceed that from the other by the length of one entire
undulation; and in these lines the movements will be once more in coincidence,
and the light will again be in excess. But between them and the central line
there will be found other positions in which the radii will differ by only half an
undulation ; and, as the movements in these positions will be directly opposed
to each other, the light should disappear. Extending this reasoning, we should
look for a series of stripes alternately dark and bright on each side of the cen-
tral bright stripe, at distances sensibly equal to each other. ‘These conclusions
are fully confirmed by experiment.*

* Prof. Potter, of London, affirms, in opposition to all other experimenters, that the centrak
stripe in this experiment is often seen dark instead of light; and in fact more usually so
than otherwise.—[ London Journal of Science, XVI, 1840. Also, Physical Optics, London,
1856.] Prof. Baden Powell, on the other hand, states that he has endeavored to verity this
assertion with every possible attention to the conditions prescribed by Prof. Potter, but
entirely without success.—[ A General and Elementary View of the Undulatory Theory, &c.,
London, 1841. ]

170 UNDULATORY THEORY OF LIGHT.

’

By means of a movable eyepiece, provided with a micrometrical apparatus,
Fresnel accurately measured the distances of these stripes from each other,
and thus deduced the lengths of the undulations by which they are produced.
In fact, as the Zocus of the central bright stripe is in the line of intersections, of
which a is one, and that of the adjacent bright stripe is in the line of intersee-
tions, of which 4 is one, we have a small triangle aéc, whose sides are severally
perpendicular to those of the triangle aS’; and accordingly,

2.858!
aS:S8S/::6c:ac; or bale = : [7.]

But ac is the length of the undulation, whence it appears that this length is
equal to the distance between two adjacent similar stripes multiplied by the
distance between the two radiant centres, and divided by the distance of either
centre from the screen. As the radiants in this experiment are merely virtual
and not actual, the values of SS’ and aS cannot be conveniently measured. But
it may be observed that the fraction

I O/
oe =2ein 3SaS/—2sin BAA’.
Hence, ac=bc.2sin $8a8/—6c.2sin BAA’. [8.

The angle SaS' may be directly measured by an instrument placed at a, ©
the angle BAA’, which is the inclination of the mirrors, may be vtherwise deter-
mined.

Putting 4 for the length of the undulation, ¢ for the angle $Sa8’, and 6 for
the distance between the stripes, the foregoing equation gives

(=2sing X06; or 0=

2sing ; [9.]

Whence it appears that the distance between the stripes will be greater as
g is less, or as the radiant centres are nearer together. ‘The same process
applied to the distance from the middle stripe to the second one on either side
will give—

2A ¢ BA
6'==—~"_; and for the third, 6/=—-, &e.
2sing 2sing

So that the successive stripes are equidistant from each other.

Grimaldi’s case of diffraction, in which the radiant centres were two minute
apertures very near to each other through which light was introduced into a
dark rocm, was manifestly analogous in principle to this. To that case the first
of the formule just given may be directly applied.

The mirrors in the experiment of Fresnel require very careful adjustment.
If, at the edges where they meet, one or the other projects, however slightly,
the effect will be sensibly impaired. A prism of glass having two adjacent faces
very slightly inclined to each other might be used to produce the interferences
by total reflection from these inclined surfaces, without being subject to this ob-
jection. ‘The other faces of the prism would require to be so adjusted that the
light might enter and emerge through them sensibly at right angles. The dis-
advantage would be that the angle of the reflecting faces would be invariable.
The experiment admits of being performed, and has been performed, by the
help of asingle mirror, placed almost but not quite parallel to the original rays,
so as to cause a portion of the wave very slightly to deviate, and thus to inter-
fere with the portion which is not reflected. In this case it is obvious that the
system of fringes produced can embrace only one-half of those which are seen
in the experiment of Fresnel.

In place of Fresnel’s mirrors Mr. Arago employed a glass prism to produce
interference by refraction instead of by reflection. Arago’s prism has a cross
section of the form of a very obtuse angled isosceles triangle; the light being
received in the experiment perpendicularly upon the base, and emerging at the

UNDULATION LENGTHS AND NUMBERS. LI

obtuse vertex in two interfering waves. The effects correspond in all respects
with those produced by I’resnel’s mirrors.

Mr. Arago also introduced a modification of the experiment, which, though
simple, is very interesting in the bearing upon theory, of its results. In the
path of one of the interfering rays he interposed a thin lamina of mica. As
mica is transparent, it was to be expected that fringes would continue to ap-
pear after the interposition as well as before; and this expectation is realized.
But as the undulation length cannot be the same in the mica as in the air, since
the refracting power of mica exceeds that of air, it was also to be expected that
the fringes would chang» their place; and this expectation also is fulfilled. he
direction of the displacement will depend upon the question, which of the two
waves, after the lamina is interposed, will be found, when they reach the position
of the originally luminous central stripe, to be advanced beyond the other in its
phase of undulation. This will of course be true of that which has the least
average length of undulation. If the undulations in mica are of less length
than in the air, (a necessary supposition, as we have already seen,) the average
length of undulation on the side of the mica will be less than that on the other side ;
and accordingly the phase at the central line of meeting will be most advanced
on the side of the mica. We must therefore assume a line upon the screen par-
allel to the central line, such that the length of path from the radiant on the side
of the mica shall be as much less than the length of path from the other radiant
to the same line, as the thickness of the lamina of mica is less than that of a
lamina of air embracing the same number of undulations would be, in order to
find the position of the bright stripe which is central in the displaced system.
The whole system is of course moved toward the side of the mica.

If homogeneous light be employed in the experiment with Fresnel’s mirrors
or Arago’s prism, equation [7.] or [8.] furnishes the means of measuring the
undulation lengths in different parts of the spectrum. In the following table
are embraced the results of such a measurement, made by Fraunhofer and
expressed in decimals of an inch, for fourteen different positions determined by
their relations to the colors or to the fixed lines of the spectrum. ‘The undulation-
lengths in this table are taken from Fraunhofer: the numbers per second are
computed on the supposition of a velocity of light of 192,700. miles to the
second.

Undulation-lengths and numbers per second.

Length of un- | Number of un- | Number of undulations

|
Place in spectrun. dulations in | dulations in | per second,
-partsotinch, | an inch.

Sree ol) | |
Pane Bee 225 ste fous Se ree . 00002708 36, 918 451, 000, 000, 000, 000
Manes et ye on ens: . 00002583 38, 719 473, 000, 000, 000, 000
Wid ierod te Paws ce eee . 00002441 40, 949 500, 000, 000, 000, COO
WM GID SS. Meno Se Saige ehalnerse . VOU02319 43, 123 527, 000, COO, 000, 000
Middle /oraniee: 22.22.22 22 A . 00002295 43, 567 532, C00, O00, O00, COD
Middle yellow...--. --- A ee . 00002172 4G, 034 562, 000, 000, 000, 000
ILA See ee ee ee SS, 2 - OO002072 48,286 | 590, 000, 000, 000, COO
Middlevoreeni 3.2/2 «36 + - eto as . 00002016 49,609 | ~~ 606, 000, 000, 000, 000
resi we Pee ree . 00001906 52, 479 | 641, 000, 000, 000, COO
WMidtiowbluds 6. 6.1)... soos 22 . 00001870 53, 472 653, 000, VEO, 000, 000
Middleindicowics.. so-2--"--2dhe . 00001768 56, 569 691, 000, 000, 000, 000
Tne ee ol eee . 00001689 | 59, 205 723, 000, 000, OOO, 000
Middlemolepie.. 2.225) 2. 17? . 00001665 60, 044 733, 000, 000, 000, 000
Piney Hees eae, 2 dees cozy! - 00001547 64, 631 | 789, 000, 000, G00, 000

172 UNDULATORY THEORY OF LIGHT.

If we compare the numbers of undulations per second in the foregoing table
with the numbers per second of acoustic undulations corresponding to a given
pitch, we shall observe that, if these vibrations had power to affect the sense of
hearing, the middle yellow would produce a tone forty-one octaves above the
fundamental C, or C between the staves; and the middle red would be forty
octaves above the “ Stuttgard pitch,” or normal A, taken at 440 complete vibra-
tions. The entire interval covered by the visible spectrum would be about a
major fifth ; between line B and line H, or the part easily visible, a major fourth.

§ V. DIFFRACTION. P

We are now prepared to understand the causes which produce the stripes or
fringes observed by Grimaldi, bordering the shadows of opaque bodies intro-
duced into a divergent pencil of light from a minute radiant point. Let R, Fig.
39, be the radiant centre, and PQ the spherical wave front, at any determinate
distance from R, as RA. In this case, as in the former, and generally in all
analogous experiments, the best radiant for the purpose is obtained by concen-
trating a small solar beam, (introduced into a dark room,) by means of' a lens of
short focus. Suppose an opaque screen § to be advanced to A, so as to inter-
cept the half wave AQ. The light which reaches the
point B, in the line RA produced, will be the resultant
effect of the unobstructed half wave PA. Let AQ
be divided, at a, 4, c, &e., into parts, such that the
lines Ba, Bd, Be, &e., drawn from the point B ona
screen BO, to the points of division, may successively
exceed each other by the length of one-half an undu-
lation; or such that, drawing the are AT with B asa
centre, the intercepts aa’, bb’, cc', &c., may have
the successive values $A, A, 34, &c. Now, if the
screen S be drawn upward from A to a, the light which reaches B will be the
resultant effect of the half wave PA, combined with the resultant effect of the
small additional wave surface Aa. This latter resultant will be compounded
of the molecular movements produced at B by the infinite number of minute
elementary waves, which may be supposed to originate from all the points of
the given wave front between A and a. Since all these elementary waves
originate simultaneously, their relative phases, when they reach B, will depend
on the differences in the lengths of their paths; and as these differences are the
intercepts between the ares AQ and AT, there will be none, until we reach a,
which will differ from the wave proceeding from A by so much as half an undu-
lation. Assuming, then, that their several intensities are equal, there will be no
complete conflict between any of the elementary waves within these limits ; and
accordingly their resultant effect must be positive, or must add to the intensity
of the light at B. If, however, we raise the screen S higher, the intercepts
will begin to execed half the length of an undulation, and some of the element-
ary Waves originating just beyond a will neutralize the effect of some of those near A.
Raising it to 6, there will be a complete series of waves originating between @
and 6, which will be in absolute conflict with the series which originate between
A and a; so that, if Aa and ad were exactly equal, and their separate intensi-
ties, as above supposed, equal also, their resultant ‘effect at B would be zero.
Aa is, however, a little larger than ad, both because of the inclination of Ba
to BA, and because of the curvature of AQ. ‘The intensities of the elementary
derivative waves are also presumed to be greater in the direction of the radius
of the original wave than in directions inclined to it, though the law of such
variation of intensity is not known. These causes of difference will, neverthc-
less, exist to no very marked degree in the immediate vicinity of the line RB,
and consequently the total effect at B of the portion of wave front Ad will be sen-
sibly null. If, now, the screen S be further raised to c, the elementary waves

DIFFRACTION—GRIMALDI'S FRINGES. 173

originating between b and c will be in complete conflict with those between a
and 6. ‘Thus the power of ad to interfere with Aa will be nearly neutralized,
and the point B will receive, once more, nearly all the illumination which Aa
is capable of sending to it. And in like manner, if the screen be successively
raised to the points d, e, &c., similar alternations of diminished and increased
brightness may be inferred. After passing the fifth or seventh division, how-
ever, these successive maxima and minima cease to be perceptible in white light :
a consequence partly due to the unequal lengths of the undulations of the differ-
ent colors, and partly to the diminishing length and increasing obliquity of the
successive divisions of the wave front.

Dr. Lloyd has illustrated this case in the following felicitous manner. Let
the light received at B from the half wave PA be represented by 1, and that
from the total unobstructed wave by 2. Represent the effect of Aa by +m,
that of ab by —m’', that of dc by +m", and so on. Then we have, ;

2=14 m—m! +m"'—m!"", &e.

Now as each of the successive literal terms is greater than that which follows
it, if we cut the series at any point the value of all the terms which succeed on
the right will have the same sign as the first of them; and the sum of the remain-
ing terms on the left will be less than 2 if the value cut off is positive, and
greater than 2 if the value cut off is negative.

Should these popular illustrations of a somewhat difficult subject appear un-
satisfactory, it may be observed that analysis leads to the same results, although
the processes are complicated. Without going into details, we may remark
that the intercept aa’ is evidently a function of the angle ARa. Put % for the
intercept, » for the angle, and V for the resultant molecular velocity at B.
Then, if all the derivative waves begin simultaneously in the are AQ, the com-
ponent molecular velocity at B, due to any elementary wave will be expressed by

vsin2az-, .dw; v being the maximum molecular velocity of the derivative wave,

and A the length of an undulation. Henee—

J()

es h se
——_—=vysin2z——vsin2za*\—
dw y pre

since % is a function of w which may be represented by f(w).
If f’() be the differential coeflicient of fw), we shall have—

fi w)aVvsin22 LZ), (a) do.

And SP )AVAVE (o)=— eosarZ) 4.0,
Or V.F(o}=5" (1-cosenL),
an 2

As fiw), which is the intercept, is always increasing with , and its differ-
ential coeflicient also, this expression makes it evident that the value of V
must pass through a series of maxima and minima, since the expression

1—cos22l%) undulates between the values 0 and 2. These maxima and minima

become, moreover, less marked as w increases, since F'(w), whatever it may be,
must increase also.

This illustration, however, excludes an important consideration, which is,
that, owing to the constantly increasing obliquity of the are w to the direction

as above given should be multiplied by the

of the intercept, the value of ¢
dw

cosine of the sum of the angles ARa and ABa; which sum.is a function of w

174 : UNDULATORY THEORY OF LIGHT.

and of the intercept itself. When » has any considerable magnitude, this

factor rapidly reduces the value of = 5 indicating a similarly rapid diminu-
GAw

tion in the fluctuations of value of the integral. On the other hand, when w

is very small, this factor may be regarded as a constant, and assumed, without

sensible error, as equal to unity.

The distance of these fringes from the boundary of the shadow may be de-
termined as follows. Suppose the screen § to be at a, and let the straight line
RaC be the boundary of the geometrical shadow. Draw aN perpendicular to
KA. Call aN, y, and AN, x By construction, Be—BA=si. Put RA=z,
BA=s, and Bag. Then,

2 2
EA aa, Y y

—s=h—Vv SS) ay? Sos —s==a +h;

q ( ) y 2(s+2) D5 ad
disregarding inappreciable terms of the root, and omitting z in the denominator
where its effect on the value of the fraction is insensible. Also, in the circle

2
; : i : J 2
whose centre is R, 2 is the versed sine of Aa, and is sensibly equal to oe

Whenec—
y a (r+s)4? “gh
j Le SSH or 7 ie ; ®
aT, 28 2rs F r+s
And putting 0, as before, for the distance BC, we have,
ro rsh a) (rs+87)A
y= = - and finally d—./ ————~. 10.
J (7+8)? r+s’ oe Tr esa)

Vrom this expression, which is the equation of an hyperbola, it appears that,
if the screen B move toward A, the /ocus of all the points in space correspond-
ing to B will be.a hyperbolic curve, of which R and a are the vertices. A sim-
ilar inference may be drawn from considering that, in all positions of the
sereen B, Ba—BA is constant and equal to 42; or BA—Ba=—43,, whence
RA+BA—Ba, or RB—Ba—RA—}2, which is also constant. But this
is the property of a hyperbola whose foci (not the vertices) are It and
a,and whose major axis is r—4A. This latter result is the strictly correct
one. The discrepancy between it and the former is owing to the omission of
minute terms in obtaining that result. Put the major axis equal A, and the
minor axis equal B. Then, by the law of the hyperbola,

B=? — A? =? (r—FAP=rl—h2; or B= Vr,
disregarding the minute negative term.
The equation of the curve. if we employ the exact values of the axes, will

be=—

mS rha—4 2?
6 =p o-aete), [11.]
which, when the minute terms are dismissed, simplifies itself to the expression
found before.

The semi-axis major of this curve being 47—4J, it appears that the curve
itself passes behind the obstructing edge at the distance of 44, at which distance
a wave reflected from the obstacle would meet a wave advancing with a differ-
ence of 44. Whether this theoretic indication is actually realized, it would
perhaps be difficult experimentally to determine. Such a reflected wave, con-
sidering only the difference of path, would be out of harmony with the advancing
wave; but, considering that its molecular movements would be reversed by
reflection from the dense ether of the obstacle, the harmony would be restored.

For the distance of the second fringe from the shadow, the expression already
found for the first answers perfectly, if we prefix to the quantity under the

BRIGHT FRINGES IN SHADOWS. 175

radical the coefficient 3; since the difference of paths Be—BA, by which it
is produced, is equal to 3A, instead of $A. For the third we prefix 5. Thus
the successive distanees are—

(rs++8*)d 3(rs+s?)A 5(rs-+s*)A
eee jaf ere eee eyes,
de

7 as

The second hyperbola passes at the distance of #4 behind the obstructing edge,
and the third at the distance of $4. Owing to the great disproportion between
the axes, 7—#$4, and WYrA—4/?, which are very nearly in the ratio of V7: VA,
the curvature is very slight except for a short distance from the vertex; so that
the branches in fact sensibly coincide with their asymptotes. But near the vertex
the curvature is very decided.

MOQRTV. From what has been said. it will be
| evident that when the obstruction
| presents a salient angle instead of a
straight edge, the fringes will pass
ne round the angle in circular ares, instead
i of making an angle also. Indeed, the
| | systems of fringes around such an
ih {| | angle are surfaces of hyperboloids of
NV. ORY V. revolution. Inthe case of re-entering
Fig. 40. angles of 90° or less, the fringes cross
each other without interference, and
are continued up to the edge of the shadow on each side of the angle. These
are casily seen to be necessary consequences of the theory of their formation.
The annexed figure exhibits the phenomena.

When the obgtructing body is large, no f.inges are seen within the shadow.
Some light strays beyond the geometrical boundary of the shadow, but it rapidly
fades away, and produces no very sensible effects. If, however, a very narrow
object be employed, the waves from opposite sides may mingle and interfere.
In this case fringes or stripes will be scen within the shadow. The light con-
cerned in producing these fringes comes from the portion of the main wave
which is c'ose to the obstruction, as the more distant parts of cach hal wave
will hold each other in check in the manner heretofore explained. Points being
taken at a, b, ¢, a’, b,c, &e., such that the succes-
sive differences of distance of these points from B
may be $2, we shall have, on each side, a series of
resultant actions alternately positive and negative, as
illustrated in the foregoing case, such as—

+ m—m! +m!!'—ml"'4-m'""", &e.

And as the effect of any portion of this series, left
by cutting off terms from the beginning, depends on
the sign of the first of the remaining terms—that is
to say, as the effect due to the first of these terms
exceeds the joint effect of all that follow—it is evident that no part of the main
wave can have anything to do with producing fringes in the shadow, ex-
cept Ca and Aa’. And since there can be no fringes produced at all, unless
the light from both sides reaches the same point, the centre of the shadow, which
is equidistant from the edges of the obstacle—that is, from the front of the
main wave—must exhibit alight stripe. On each side of this will be found posi-
tions, as for instance B’, where the distances from A and © differ by half an
undulation; and here the darkniss will be complete. At distances a little greater
will be found positions where the differences of distance from A and C amount
to an entire undulation; and here will be found once more bright stripes. If the
object be very narrow, these interferences may occur not only throughout all

J
tf

Fig. 41.

176 UNDULATORY THEORY OF LIGHT.

the shadow, but to some distance into the light on each side. Should any evi-
dence seem to be needed to confirm the theory on which the formation of these
fringes has been explained, it may be found in the fact that if, by an interposed
card, the light from one side of the opaque object be arrested, all the fringes
will instantly disappear from the shadow.

As for the form of the /oct of these fringes in space, since each is determined
by the intersection of radii from A and C, having a constant difference, they are
necessarily hyperbolas, having A and C for their foci. But in this case it is the
principal axis which is small, while the conjugate axis is comparatively very
great; so that the curves are widely open, having but slight curvature even at
their vertices.

Let B/A—B’/C=2x 44, n being any integral number, even or edd. It is
evident, from the law of the hyperbola, that 4zd is the principal axis of the
trajectory of B’. And, putting CA=c, the conjugate axis will be Y¥?—jn’*?.
Making this the axis of y, and the former the axis of z, the equation of the

curve gives us—
» C— in? ( )
pat | —_ +).
An??? 2
Suppressing the minute term 4x?” from the numerator, and reducing the
equation with respect to z, we obtain—
a (47° +e)v?
According to the notation heretofore used, y, which is the distance of B from
the object AC, may be replaced by s. Also c’, in the numerator under the
radical, may be dropped without appreciable error, except when B is quite near

to the object. The simplified expression will then be— :
> Bk ae : . :
d==-,~ which is the equation of a straight line. [15.]
Qe

At any considerable distance from AQ, therefore, as compared with AC, the
hyperbolic trajectory sensibly coincides with the asymptote to the curve. In
fact, the equation of the asymptote being—

A And
Dina ——— ie 16.
BY? V 21? Y [ ]

by rejecting the minute term under the radical, we obtain—

niy' sna hae ie / ;
5.5} which is identical with the former.
aC aC

'
<< O

By substituting different numerical values for x, this equation serves for all
the fringes, light or dark. The even numbers give the loci of the bright stripes,
and the odd those of the dark. The distance 0 is in all cases measured from
the middle of the central bright stripe.

The expression for the value of 6 indicates, at sight, that the fringes will
increase in breadth, as the opaque intercepting object diminishes in diameter.
In fact, 0 is inversely as c, and to double the
breadth of the fringes, we have only to reduce
the diameter of the object one-half. Accord-
ingly, if a tapering object, as a sewing needle.
be employed, the fringes will spread out toward
the top with a beautiful plumose appearance.
This becomes still more striking when the taper
is is more rapid, as when we use an acute-angled

Fig. 42. or even a right-angled plate of thin metal. ‘The
fringes, which in this case are very remarkable, have been called Grimaldi’s
crests. :

DIFFRACTION BY MINUTE APERTURES. Ad,

The next case which presents itself is that in which a small portion of the
wave only is allowed to pass through a narrow opening in the obstructing
screen, having straight and parallel sides. In this case a position may be found
for the screen B, in which, if RAB (Fig. 43) be
drawn from the radiant through the centre of the
aperture, Ba and Ba’, drawn from B to the edges,
may exceed BA by one-half an undulation. All
lines drawn from B to points of the wave front
nearer to A than aor @’, will differ from BA less
than half an undulation, and the point B will be
fully enlightened. If then the screen B be advanced
toward A, there will be found somewhere another
position in which Ba and Ba' will exceed BA

Fig. 43. by an entire undulation. The spaces Aa, Aa’,
may then be divided somewhere, so that lines drawn from the points of
division to B shall once more differ from BA by half an undulation. All the
molecular movements excited at B by the segments next to A will then be in
conflict with those which are generated by the segments next to a and a’; and accord-
ingly in this position of B the middle of the luminous image will be occupied
by a dark stripe. By advancing B still nearer, another point may be found,
where Ba and Ba’ will differ from BA by three halves of an undulation; and
in this case the ares Aa and Aq’ may be divided each into three parts, such that
the distances of the points of division from B may successively exceed each
other by half an undulation. The pair next to @ and the pair next to a’ will
then neutralize each other, while the central pair will be efficient, and the point
B will be again illuminated. Thus, by varying the distance of B from a, the
dark stripe in the centre of the luminous image will alternately appear and dis-
appear. It is obvious, however, that when the distance is fcund at which
Ba—BA is exactly one-half an undulation, the dark stripe will not return at any
greater distance. As the screen B approaches A, on the other hand, the entire
bright image becomes filled up with fringes, increasing in number, with the
central one alternately dark and bright. It is also sufficiently remarkable and
striking that if, when B is at the maximum distance producing a dark centre, a
very narrow opaque object be placed over the aperture, parallel to its edges, so
as to intercept exactly one-half the light, leaving equal portions on each side of
it to pass, the brightness of the centre will instantly return. It will disappear
again when the opaque object is removed. When B is at other positions nearer
to A, producing the dark centre, the restoration of central brightness will not
necessarily take place on cutting out the central half of the beam; but it may
be effected by cutting out a portion which is somewhat more or less than half.

In order to understand the conditions upon which this difference depends, we
must consider that the dark stripe appears in the centre only when La—BA is
equal to an even number of half undulations. But even numbers of two kinds,
the even-even, and the odd-even.. The even-even are all of them multiples of
2 by the arithmetical series of even numbers 2, 4, 6, &e.; the odd-even are mul-
tuples of 2 by the odd numbers 1.3.5, &e. If, then, Bea—BA—nx d/, the light
will be restored to the central dark stripe by stopping out the middle half of the
beam, whenever » is an odd-even number; and the interposed opaque body
must exceed or fall short of half the breadth of the beam by the breadth of two,
at least, of the divisions of the wave front, (2z in all,) into which the space aa!
is Supposed, in the foregoing explanation, to be divided, in order to restore the
brightness when x is an even-even number. We here assume the several divi-

1278

178 UNDULATORY THEORY OF LIGHT.

sions of the wave front to be equal in extent, which is sufficiently exact for the
purpose in view. The other dark stripes which form
within the bright image of the opening aa’ are sub-
ject to fluctuations of intensity similar to those of the
central one. ‘lo understand this, let d be a point so
7\" taken, that da!/—ba—=2. Join bR, and let the line

= A
zie Np ba revolve round Ré to the position le. Then dc=

SZ
ae ba, and ba'’—be=2. Divide ca’ at d into parts,

LY

such that bda'—bd=4/, and bd—bc=3i. Then, so
far as this portion of the wave is concerned, the
point J will be obscure in every position of & which
preserves this relation, whatever be the distance from
A. Also, at any distance of & for which the divisions

» Fig. 44. of the wave front ac, made as heretofore described,
are an even number on each side of Rd, the whole effect of the wave at & will
be null, and the point 4 will be obscure. But if the number of these divisions
on each side of R& be an odd number, there will be a portion of the wave un-
neutralized, and 4 will be illuminated. :

The fringes exterior to the bright image of the opening are more beautiful
than those interior to it, being, especially when the aperture is very narrow,
richly colored. They are not subject to the fluctuations of brightness, as the
distance of B from the aperture varies, which attend the interior fringes; since
the lines da and da’, drawn to any point in any of those fringes from @ and a’,
the limits of the aperture, will be both on the same side of Ré.

The distances 0 from the central line B are all determined by the same
equation which was found for the fringes formed by a narrow opaque object.
Indeed, the geometrical conditions in the present case are identically the same
as those in that. he optical difference is, that the even values of 2 give the
loct of the dark stripes, and the odd those of the bright. The breadths vary,
as before, inversely as c, which is the diameter or width of the aperture. With
apparatus in which the opposed edges are movable, the expansion of the
fringes, as these edges are made gradually to approach each other, is very
striking. When the aperture is a very slender isosceles triangle, they spread out
widely toward the vertex. The expression,

pateh,
2c

also shows that the breadth varies directly as the length of the undulation. © In
homogeneous light, therefore, the broadest fringes are obtained with red, and
the narrowest with violet. In such light, a dozen or twenty may easily be
counted. When white light is employed, the overlapping of the colors, while
it improves the beauty of the display, reduces very much the number that can
be distinguished. When monochromatic light cannot conveniently be obtained,
the same effects may be substantially produced by viewing the fringes made by
white light through colored glasses.

When, instead of a long and narrow aperture, a small circular opening in an
opaque plate is used, the fringes are, of course, circular. In this case, the cen-
tral dark stripe of the preceding experiment becomes a central dark round spot.
This spot disappears and reappears as the screen is brought nearer the plate, at
the same distances at which this effect was observed in the-central stripe in the
image of the oblong aperture. Referring to the last figure, and regarding aa!
as the diameter of the circular opening, when Ba—BA=2 x3), there will be
some point between a and A (suppose a’) which, if joined to B, will give
Ba’ —BA=32. Now, it has been shown that Ba—BA varies as y’; the radius
of the aperture (or of the part of it considered) being represented by y. Hence,
for the point supposed, a”, we have Aa@’?=A2a!”; or the circle of which Aa is

DIFFRACTION OF OPAQUE DISK. 179

the radius, is double in area of the circle of which Aq” is the radius. But since
Ba—Ba"'=3A, and Ba”—BA=d,, it is obvious that the resultant molecular
movement produced at B by the circle of which Aa” is the radius, will be in
total conflict with that produced at the same point by the portion of wave front
which forms the ring between this circle and the circumference of the orifice. It
is this conflict which produces the dark spot at B. If now a small opaque disk
could be introduced into the middle of the orifice, exactly equal to the cirele Aa”,
stopping out the central pencil of light, B would immediately become bright
again.

If Ba—BA=4~x #, the circular aperture will be made up of a central
circle and ¢hrce concentric rings, of equal areas, producing movements at B
alternately equal and opposite. B will accordingly be obscure. If we stop out
now one-half the area in the middle—that is to say, the central circle and the
first ring—B will still be obscure; but if we stop out the central circle and the
two interior rings, the light at B will be restored. Or if we stop the central
circle only, or, instead of that, the exterior ring, or (which is the same thing)
apply over the aperture a smaller one, having only three-fourths the area of the
first—in either case the light will be restored. But if we stop the central circle
and the outer ring at the same time, B will remain ovscure.

Generally, if Ba—BA=x x $A, » having any integral even value, the centre
of the bright image of the aperture will be dark. If'z be odd-even, stopping
out one-half the area from the middle of the aperture will restore the light. If
n be even-even, stopping out one-half the area will produce no change ; but the
light may be restored by stopping a portion of the area which is by a certain
amount greater, or by the same amount less, than one-half. In all these cases
the light at the centre, when restored, will be sensibly equal in intensity to that
which would reach B through an orifice of the size which would give
Ba'’—BA=3,.

This incidentally leads us to the remarkable result that if, in this experiment,
instead of a circular aperture in an opaque plate, we employ an opaque disk
attached to a transparent plate, ‘the centre of the shadow will be as highly
illuminated as it would be if the wave were not interrupted at all. For an open
circle whose centre and circumference give the relation Ba'’—BA=#), and
a ring whose exterior and interior circumferences give Ba—Bu''—$)/, pro-
duce sensibly the same illumination at B. In either case all the remaining ob-
structed portion of the wave exterior to them may be divided into rings, whose
relation to the unobstructed part will be alternately negative and positive,
and whose total resultant (which takes the sign of the first term) will be op-
posed to that of the unobstructed portion. If then this exterior portion be
allowed to pass, the etiect, in either case equally, will be somewhat to diminish
the intensity of the brightness at B, which brightness therefore will still remain
equal for the circle and for the ring. But in the first instance, this is to allow
the entire wave to pass; while in the secoud it leaves the disk. The centre of
the shadow of the disk, therefore, which is the point B, is as much illuminated
as the same point is when the wave is wholly unobstructed. ‘This curious cir-
curnstanee, wh'ch was first announced by Poisson from theoretic considerations,
is easily verified by experiment.

When it is said that an open cirele which gives at its centre and its circum-
ference the relation Ba’—BA—x x $/, ora ring of which the outer and inner
circumferences furnish a similar relation, will exhibit a dark spot at B whenever
m is an integral even number, it must be remembered that this proposition is
true only of the rays whose undulation lengthis 2. If 2 is the undulation length
of the red rays, and 2! that of the blue or violet, then at the distance at which
red disappears, the blue or violet will not be entirely suppressed. We have

180 UNDULATORY THEORY OF LIGHT.

(7s)

seen that Ba'—BA has a value expressed by the formula A= 3
rs

y”, y being the
radius of the circle. This may be resolved into the paris,

ya

Qr ° Qs’
of which the first is constant when y is constant, and the second varies inversely
as s, which is the distance BA. ‘The less the value of 2 (=x 42), the greater
will be the distance at which the color corresponding to 2 will be suppressed.
And as the color which remains is the difference between the color suppressed
and white, it follows that, as the eye approaches A, in the line BA, the ring or
the aperture will assume successively all the tints of the spectrum from red up-
ward, and that this series may be several times repeated. Moreover, putting A
for the length of the red, and i’ for the mean length of undulation in the com-
pound color complementary to red, which will correspond nearly to the wave
length in the green, when Ba’—BA=(2n+1) X $4! <(2u+1) x $4, a point b
may be found on any side of A, but very near it, at which 6a’—bA—(2n-+1)x 4A.
A green circle will therefore appear surrounding A, while A itself, whether
it be an aperture or a ring, will be red. Also, at other distances, greater or less,
circles of other tints will appear; so that the ring or aperture will be encircled by
a corona displaying all the prismatic colors, from red to violet, shading outward.

As the eye approaches A, the equation da’—bA=(2n+1)xX4A will be true of
points nearer and nearer to B, until 6 and B coincide. 'The rings will therefore
appear to be successively absorbed into the aperture. In withdrawing the eye, they
will seem to be, in like manner, evolved out of it. In this experiment the aperture
should be very small or the ring very narrow, in order that the tints may be vivid.

It will readily be understood that the obscurity and the sharp edges of shadows
of bodies of considerable size are owing to the smallness of the values of 4 for
all the rays of light. On this account, if any point be taken within the line of
the geometrical shadow, and if the wave front, beginning at the edge of the
opaque body, be divided into portions whose extremes are remote from that
point by distances differing $2, these portions will neutralize each other’s effects,
except for positions of the assumed point for which the divisions have (as they
may near the shadowing body) some slight inequality, and no material obliquity.
Such positions can only be found very near the line of the geometrical shadow.

To the same cause it is owing that, in
refraction and reflection, the beam re-
fracted or reflected is as sharply defined
as the incident beam. ‘The demonstration
which we have given of these effects, from
Huyghens, contains an imperfection on
this point, which I*resnel has supplied.
Referring to the figure, suppose that an
undulation originating at b should take
the direction BA, different from that of
the main reflected wave, BQ’. ‘There

Vig. 33. will always be found, to the left of B, a
point, as 7, from which another undulation will follow in the parallel and nearly
coincident line xh, differing from the first by half an undulation. Draw wo per-
pendicular to BB’ and B¢ perpendicular to 2h; onB is the angle of incidence.
Put p for xBé. Then Bo=Bn sin:, and xt—Bz.sinp.

Now, when the wave whose front is Bé starts from 2, the movement which is
to produce the wave from Bis ato. There will accordingly be interference, if
nt—Bo—=}A; that is, if Bu.(sine—sin:)=$4. But since 4 is very small, if sinp
sensibly exceed sint, Bn will be very small; showing that interference will
take place from a point very near B. As sing approaches sins, the distance of
the origin of the interfering wave will be greater; but there will de an interfering

DIFFRACTION OF GRATINGS. 181

wave, (if the surface AB is unlimited,) in every case except that in which
sinp—=sin ¢; that is, in which Bé coincides in direction with the regularly re-
flected wave. ;

In like manner, in the case of refraction, if we suppose a wave to diverge in
the direction Br, draw ng parallel to Br and Bp perpendicular to it. Call the
angle nBp, p, as before. ‘Then Bo==Bu.sin:, and xp—Ba.sinp. But np being
the path of a wave in the denser medium, it must be multiplied by the index of
refraction, in order to obtain the equivalent distance, or distance which the wave
would have moved in the same time, in the rarer. Let x be the index of re-
fraction, and we have, for the condition of interference, Bz.(msinp—sins)—=dA.
If nsinp is sensibly greater than sins, Bx must be very small. And for any
value of xsinp—sin:, there will be a distance Bx furnishing a wave of inter-
ference, if the surface AB is unlimited; except only for the value xsinp—sin:-—0,
when the ray Br ceases to diverge from the direction of the main refracted wave.

These reasonings assume that the forces of the elementary derivative waves
are the same in all directions. But it is probable that these forces are less in
lines oblique to the direction of progress of the primitive wave than iz that di-
rection. How far this is true could be casily investigated experimentally, by
employing apertures less than the length of a haJf undulation in diameter, were
it not that the extreme minuteness of such apertures (the mean length of a half
undulation not exceeding one one-hundred-thousandth of an inch) would render
the light too feeble for the purpose.

Some material for the formation of an opinion on this subject may, however,
be gathered from certain phenomena of diftraction first observed by Fraunhofer,
more remarkable and more brilliant than any which have been thus far men-
tioned. If a single very minute aperture will not furnish light enough for
experiment, an assemblage of very many very minute apertures, closely grouped,
may do so; and if these be so arranged that, for any determinate point in the
shadow, they shall allow only such portions of the wave front to pass as conspire
in their effects at that point, while the intervals between them obstruct those
portions which conflict, we shall possibly find that the tendency of a wave
originating in a single molecular impulse to expand equally in all directions, is
much more decided than had been supposed. Fraunhofer’s original experiments
were made with gratings formed by stretching an exceedingly fine wire across
two parallel screws of a great number of threads to the inch—the threads
serving to keep the wires equidistant. He subsequently employed gratings
formed by cementing leaves of gold to glass and cutting them through in very
fine parallel lines ruled with a sharp instrument. Instead of these, also, he
employed similar lines ruled with a diamond on glass itself.

The results of such an arrangement may easily be predicted. The image of
an aperture closed by such a grating will appear bright, as though the obstruction
were not interposed. But toward either side, in the direction perpendicular to the
lines of the grating, will be found several points for which the part of the wave
which the grating obstructs would if allowed to pass be more or less in conflict with
those which it transmits; and which, therefore, are bright when the grating is pres-
ent, and dark when it is absent. Suppose, for simplicity, that the open spaces and
the opaque bars are equal in breadth. Let
da, a, a, represent several of these open spaces,
and 4, b, b, &c., the intermediate bars. A
point, P, may be found from which lines being
drawn as in the figure, and perpendiculars le:
fall upon them from the edges of the aper-
tures, as at c, c, d, d, will give cd = $A,
db =$A, and therefore ch 2. The distances
from P to the corresponding parts of the sev-

Fig 45. eral openings will thus differ by an entire un-
dulation, and besee the waves which reach P through them will be in harmony.

18

Lo

UNDULATORY THEORY OF LIGHT.

The distances from P to the corresponding parts of the obstructing bars will
differ from the distances to the adjacent openings by half an undulation; and,
accordingly, if the bars were removed, the wave which would proceed from those
points would neutralize the effects of the former: but being obstructed, P remains
illuminated by the resultant effect of all the first set of waves.

Furthermore, since the position of P is determined by the condition that cd
shall be the length of an undulation, it will be necessary to take P further from
B for the longer undulations and nearer for the shorter. The different colors
will thus be separated, and a perfect spectrum will be formed on the screen.

Should the point P be taken so that cd is equal to two undulations, there will
be no spectrum: for in this case ed will.be equal to one undulation, and as in
the cases we have considered of a single aperture, one-half of each opening, a,
will hold in check the other half. If we find still another point where dc is
equal to three undulations, then ed will equal one undulation and a half; two-
thirds of each opening will then be neutralized, but the remaining third will be
effective; and there will be another spectrum, but less brilliant than the first.
Tf dc = four undulations, the spectrum will again fail. If de — 52 it will return,
and so on.

If the bars are broader than the open spaces, there will. be a spectrum for
beni, m being any integral number; until the light is too feeble, or until
cd wd, n! being also any integral number. If the spaces are broader than the
bars, there will be a spectrum for every integral value of min be==nd until

a+b
2 —
b

ab :
If, however, — is not integral, take g— the greatest common measure of a

a+b

g
Put this value of 2 equal to m, and we may say generally that the mth spectrum
will fail, and also the mth, m being, as before, any integral number. If @ and
é are incommensurable, there could be theoretically no perfect spectra, or spectra
of maximum brilliancy; nor would any speetrum absolutely fail: but a near
approach to failure would occur for approximate values of g. All these propo-
sitions result so obviously from the construction above given, that they require no
demonstration.

The same construction indicates a simple expression for the deviation of each
spectrum from the directio.’ RB, of the radius of the original wave. For rep-
resenting this deviation by 0, we have—

, (a and 6 standing for the breadths of the spaces and bars severally.)

and 6. Then »=

will give the number of the first spectrum which will fail.

sind=——. [17.|

Putting 2 = 1, Aone fifty-thousandth of an inch, the length of the mean
undulation, and supposing one thousand opaque lines to the inch, the formula
gives us, by substitution, sind—0.02—sin 1° 9’. As the sines of small angles
are very nearly proportional to the angles themselves, the deviations of the suc-
ceeding spectra will be nearly the double, triple, &c., of this. And as thé de-
nominator, a+, is the reciprocal of the number of lines to the unit of measure-
ment to which 4 has been referred—in this case to the inch—it is evident that
the sines of the deviations will increase directly as this number. With five
thousand lines to the inch, the fifth spectrum will have a deviation of thirty
degrees. The force of the derivative waves from minute apertures thus appears
to be great even at large obliquities, when the obstructing effects of interference
are removed.

In the above expression for sind, if 2 be put equal to 1, and a6 equal to 4,

COLORS OF THIN PLATES. 183

sind is unity, indicating a deviation of 90°. A grating, therefore, in which the
number of lines to the inch is equal to the number of undulations in the same
space, will produce no spectra. The same is true, @ fortiori, of still finer
gratings.

The spectra formed in this way by diffraction will easily be understood to
form the best of all possible measures of the lengths of the undulations corres-
ponding to the different colors. They exhibit very distinctly the principal lines
of Fraunhofer; and these lines, as might be inferred as a theoretical necessity,
preserve invariably the same relative distances from each other. 'The spectra
formed by refraction afford measures, not of the relative lengths of the undula-
tions in vacuo, but of those lengths as modified by the media of which the
refracting bodies are composed. “App: ently these modifications are not simply
proportional to the lengths of the undulations. Mr. Cauchy’s investigations
upon dispersion show, as we have seen, that they ought not to be.

Light veflected from finely ruled surfaces exhibits colors, as well as that which
is transmitted through them. These efiects are produced by interference, and
are explained upon principles analogous to those we have been considering.
Some substances are naturally marked with sinuosities which produce these
effects. A familiar example of this kind is seen in mother of pearl. Sir David
Brewster found that an impression of the polished surface of this material taken
in wax, exhibited the same colors as the substance itself.

The effects produced by diffraction may be endlessly varied, by employing
(instead of gratings) reticulations, and groups of apertures, of various figures,
symmetrically disposed. Many of the phenomena are exceedingly rich and
beautiful. We must content ourselves with the examples which have been
given, and which illustrate the general principles on which they all depend.

§ VI. COLORS OF THIN PLATES.

We will now proceed, very briefly, to apply the theory of undulation to the
explanation of the colors seen in thin transparent plates ; or, as they are com-
monly called, Newton’s rings. These, when scen by reflected light, are caused
by the interference of the wave which proceeds from the lower surface of the
plate with that which is reflected by the upper. Let us suppose, at first, for
simplicity, that the light employed is homogeneous. Where the dark rings
occur, there must be a difference of path between the interfering waves, of one-
half an undulation. Now the wave which is reflected from the lower surface,
passes through the thin plate twice; and that which is reflected from the upper
surface does not enter the plate. - The difference of path is therefore twice
the thickness of the plate; and this ought apparently to be equal to half an un-
dulation, or to some uneven multiple of half an undulation. Let @ represent
the thickness, and » any integral number; then—

20==(2n4+-1)x4A: and when n=—=0, 204), or 0= HA.

It should seem, accordingly, that the first dark ring should appear, where the
thickness is equal to one-quarter ef the length of an undulation. As the thickness
increases toward 0=-5/, or diminishes twa 0=0, the light should gradually
appear; aud when cither of these values is reached, we should have the maximun of
brightness. The centre of the system should then be bright. It is not so, how-
ever, but on the other hand is entirely dark. ‘The reason of this apparent dis-
Ceetence with theory will be understood, when we recall the circumstance,
thus far disregarded, that the reflection at the lower surface takes place as
the ray is proceeding from a rarer to a denser medium; while that at the
first surface occurs as the ray is passing from a denser and to a rarer.
It has been already shown that, in the latter of these cases, the molecular move-
ments maintain their original directions; while in the former, these movements

184 UNDULATORY THEORY OF LIGHT.

are reversed. But to reverse the molecular movements of a wave is to change
its phase half an undulation. Accordingly, at the points where 0=}A, and
where the difference of path is $A, the difference of phase is $A+3A=A. This
thickness should accordingly give a bright ring, and not a dark one; and so it
is in fact observed to do.

If there could be any hesitation about receiving this explanation of the
phenomenon, it may be entirely removed by considering the following two
experiments. My. Babinet having produced, by means of Fresnel’s mirrors, the
fringes of interference already described, recived the interfering pencils upon
a glass mirror, of which one half was transparent and the other half silvered
on the back. The reflected pencils, thrown upon a screen, still exhibited the
fringes. When both the pencils were reflected from the silvered part of the -
mirror, or both from-the transparent part, the fringe in the middle continued to
be bright, as in Fresnel’s original experiment. But when one of the pencils
was reflected from the transparent glass and the other from the metal, the middle
fringe became immediately dark. "The other experiment alluded to consists in
introducing between the two lenses, in Newton’s experiment, a fluid having a
refracting power intermediate between that of the upper and that of the lower
glass. With a crown glass above, having the index 1.5, and a flint glass beneath,
with the index 1.575, the oil of sassafras (index 1.53) or that of felaves s (index
1.539) introduced between will convert the dark rings into bright ones, and vice
versa. In this case the rays, at both surfaces alike, are passing from a rarer to
a denser medium.

When the rings are viewed by oblique light the undulatory theory requires
that their apparent magnitudes should be governed by the following law. If
MM’ be the upper of two glass plates, with par-
allel surfaces, enclosing a lamina of air between
them, and if IPQSTVRK be the path of a ray
incident obliquely at P, and reflected at the lower
surface of the lamina at the point S, this will fall
= sS=U jn at T with another, reflected from the upper

ne surface at T, whose path is NOTVR. When

sy the first is at P the other is at N, in PN, drawn

from P perpendicularly to NO. These two have the same length of path in

the medium MM’. Their difference of path will therefore be QS+ST_NO,

or 2ST—NO. As the angle NPO is equal to the angle of incidence (which
put == ¢,) and also KST, we shall have—

sin? ¢

z 20 ; rice
28T=— , and aay Tsin:-—20tan:sin:—=20
cos:

cose”
Eo 1—sin” f
Hence 28ST—NO=20 =20coss.

But in order that there may be interference, ne difference of path must be a
multiple of half an undulation. Henee—

AA
20cosc—=nx HA, or 0=n——=nxAA.secr. [18.]
cos:

In which z is an odd number for the bright rings and an even number for the
dark. At oblique incidences, therefore, the thickness at which a given ring
appears Is greater than at a perpendienlar incidence, in the ratio of ‘the secant
of ineidence to unity, or in the inverse ratio of the cosine of incidence to unity.
But this is the law which observation had established before the theory of
undulation had indicated its necessity.

There is still one point to be attended to before the theory of the phenomenon
is complete. The dark rings, as seen by reflection in homogeneous light, are

absolutely dark, showing that the interference is total. But the amount ‘of light

COLORS OF THIN PLATES. 185

in the two conflicting rays ought to be equal in order to produce this effect. Now,
if we assume (what will hereafter be proved) that the amount of light reflected
at either surface is in a constant ratio to the amount of light inc ident upon it,
when the angle of incidence and the index of refraction are ‘themselves constant,
we shall perceive that the ray which emerges after one reflection at the lower
surface is feebler than that which is reflected at the upper: for the light incident
upon the lower is already enfeebled by the loss at the upper, and the reflected
ray is again diminished by the second reflection which occurs at its emergence
through - the upper. But the light which is thus turned back at the upper surface
is again reflected at the lower, and at its return another portion emerges through
the upper. A series of reflections thus goes on between the two surf: 2CeS, each
one contributing to strengthen the emergent ray; and the resultant of all these
contributions is to bring the ray from the lower surface, in the end, up to exact
equality with that which is originally reflected from the upper without entering
the lamina. This will appear to be rigidly true if we consider the following
statement. ‘lhe intensity of light is measured by the living force which ani-
mates the mass of ether in which the molecular movements are going on. Let
the masses in the two adjacent strata of the two media which act upon each
other be distinguished by the letters m for the denser and m! for the rarer. Now
it is true (as will hereafter be proved) that the velocity of molecular movement
in a wave reflected from the separating surface of two given media, at a given
incidence, bears a determinate ratio to the molecular v elocity i in the incident wave.
Let this be represented by the ratio v: 1, the incident velocity being unity.
Then the living force of the reflected wave will be mz?, and that whic it passes
into the sag me dium and forms the transmitted wave will be m(1—z*). Ae-

cordingly ~~ “(le ) is the square of the molecular velocity in the transmitted

wave. et it be represented by w’.

By reflection at the second surface, w becomes ew, and this, by another reflee-
tion of the returning wave at the first surface, becomes vz. From the living
force of the wave returning from the second surface subtract the living foree
which it loses by the second reflection at the first, and the remainde vr, which is

the living force transmitted through the first surface, will be m'vu? (L—v’).
2!

And this, divided by the mass m, gives mew (1—v”) for the square of the first
m

component of the molecular velocity in the wave which reaches the eye from the
second surface. In like manner v?« becomes vw by second reflection at the
second surface; and v*u becomes v*u by the ieceediae reflection at the first
surface. And the expression for the eet of the second component of the

mn!
molecular velocity we are seeking, will be ~ v8’ 2(1—~*). The next term will
m
am! ogee
be — vu? (1—v*); and from a comparison of these three the law is evident.
m

By substituting ‘the value of wv, taki ing the square roots of these squares and
making their sum, which is the re sultant molecular velocity of the wave emergent
from the second surface, equal to v’, we shall obtain—

v' =(1—2’) (vt torte... +0"),

a pee
The sum of the series in parentheses is 7 Hence v/v, or the reflected
Uv —_—

velocities, and consequently the intensities, of the waves reflected from the
two surfaces, are equal.

It is assumed in the foregoing that all these components agree in phase. But
this is evidently true at the points where the dark rings, as seen by reflection,
appear. For at these points the first return wave from the lower surface is in

186 UNDULATORY THEORY OF LIGHT.

conflict with the advancing wave, which it meets at the first surface. This
advancing wave does not change its phase by refraction, but the reflected part
of the return wave does so, and is therefore in harmony with the advancing
wave which it joins. The two accordingly conspire from that time forward ;
their emergent portions at the second surface producing a bright ring by trans-
mitted light, while their reflected portions, returning to the first surface, conflict
with the zext advancing wave which they mect there.

But at the points where the drzght reflected rings appear, the case is different.
The return wave is in harmony with the advancing wave which it meets at the
first surface, and its emergent part conspires with the reflected part of the
advancing wave. But its reflected part, losing half an undulation, conflicts with
the transmitted part of the advancing wave, and thus produces, by subsequent
transmission through the second surtace, a ring partial y obscure, but not entirely
so, from the great inequality of the conflicting molecular velocities. If we
disregard the sucecssive advancing waves, and consider the successive values of
the terms vz, v"v, 7u, &e., at these points, proceeding from a single original
wave, we shall fiud them alternately positive and negative. Their emergent parts
must be so likewise. And since they are decreasing, their sum takes the sign
of the first term, which is positive; so that their resultant conspires with the
wave reflected to the eye from the first surface. The components, simultaneously
reflected to the second surface from the ‘first, form a similar series with signs
reversed, and therefore have a negative resultant, conflicting with the wave
emergent at that surface.*

* This matter may perhaps be made more clear as follows:

Calling, as above, wu the value of the molecular movement in the ray transmitted through
the first surface, and v the ratio of reflected to incident light, the advancing and returning
waves within the lamina will have the successive molecular velocities—

1. Advancing wave, uw, UU, vu, vou, eu, &e.
2, Returning wave, vu, vu, vu, vu, &e.
And the squares of the velocities of the emergent components will be—
. mi. ee area, eee eee ae uv m ,
Ist surface, —(v2u*—vtu*), —(v®u?—v*u*), —(vwe—ol?u?), —(vr4u?—vl6y?), &e.
Vt mn ae ne
7? it / /
Tlie oy ate m SY Fae Meda p MU cere a
2d surface, —(ur—viu2), —(viw—v'u?), —(e8u?—olu?), —(v?ue—v4u?), &c.
mn +m m m

Consider the movement in the incident wave to be positive. Then if the lamina were
without thickness, the successive reflections still going on, the sign of the movement in the
diminished waves successively emergent would ke always positive for the second surface,
(for which the number of reversals by reflection is always even, ) and always negative for the
first, (for which the number of similar reversals is always odd.)

By giving greater or less thickness to the lamina, any difference of path may be introduced
for either the rays seen by reflection or those seen by transmission. If @ represent the thick-
ness, the differences of path which wiil exist, after the several successive reflections, will be
20, 40, 60, or generally 2m0, m being any integral number. If G=2 X $A, or 2O=2n X fA=—nd,
a. being also any integral number, it is manifest that 2m$=mn2, being a number of complete
undulations, cannot change the sign of the movement, whether 2 be even or odd.

But if 26==(2n--1) xX}, then 2mP=m(2n-+1) x 4A will be an odd number of half undula-
tions when m is odd, and an even number of half undulations, or an integral number of
complete undulations, when m is even. Accordingly, the wave changes its sign for every
odd value of m.

Hence, if 26=n2, or =n XA, the movement will be negative for all component waves
emergent from the first surface, and positive for all emergent from t!

he second.
Also, for 20=(2u-++1)X4A, or 6=(2n-+1) XFA, the signs will be alternately positive and
negative at the first surface, and negative and positive at the second.

For the first case, if we take the square roots of the squares of the’ emergent components
given above, substituting the value of w, we shall have for the resultant v’ at the first surface,
o'=(v2—1).(v--v3-Lv5....ad inf.) Whence v’=—2.

The interference is therefore absolute, and the rings formed at these thicknesses will be per-
fectly dark. ;
For the rays emergent at the second surface we obtain the expression—

w/=(1—v?).(1-e2-et....ad inf. )=—08), a,

COLORS OF THICK PLATES. 187

In these explanations we have supposed the incidence perpendicular, and
have regarded the faces of the laminw as parallel. In the case of Newton’s
rings, neither of these suppositions is usually true; and the second can never
be so. The inclination of the faces is not, however, great enough sensibly to
affect the conclusions. In the case of oblique incidence, it is obvious that no
ray reflected from the second surface can return to the same point of the first
surface (supposed parallel) at which it entered. But the loss occasioned by
this deviation is made good by the reflected component of some other ray
parallel to the first, in the plane of incidence and on the other side of it rela-
tively to the point of emergence.

It will thus be seen that the colors of thin plates, for which, on the theory of
emission, it is difficult to assign a cause which does not introduce as many dif-
ficulties as it removes, are all necessary consequences, on the undulatory theory,
of the simple principle of interference. 'The hypothesis devised by Newton to
account for them has not been presented, since it is now generally abandoned,
and the limits of these lectures would not allow its introduction.

The colors of thick plates, of which some examples were noticed in the intro-
ductory lecture, depend on causes similar to those above explained. In the
case iustrated in Fig. 8, which we here introduce again for the sake of the
explanation, if the light entering at o be composed of rays
perfectly parallel, and be reiurned from the spherical sil-
vered glass mirror, by a perfect specular reflection, to the
perforated screen ¢, placed at the centre of curvature, it
will all of it pass through the perforation toward 0, and
no rings will appear; or at least only such as might be

Fig. 8. due to the diffraction of the aperture, very much enfeebled
by the reflection. But if the first surface of the glass be
imperfectly polished, the specular reflection will not be perfect, but there will
be a reflected cone of scattered light at the first incidence. This has nothing
to do with the phenomenon. There will, however, be also a transmitted cone
of scattered light, which will become at the second surface a reflected cone,
having a virtual apex behind the mirror. Moreover, the light transmitted and
subsequently reflected regularly, will, at its emergence after reflection, form a
second scattered cone, the rays of which will have a virtual origin behind the
mirror, though the apex of this cone is at the first surface. The condition of
the light of these two cones is easily seen to be such as to produce interference ;
hence the formation of the rings observed in the experiment.

That is to say, the brightness of these transmitted rings is equal to that of the incident light.
In the second case, the equation for the first surface is,
v'=(1—v?).(v—v3--v— 07... .ad inf.)
This may be separated into two equations, thus:
Put v’=w-+-w’,
Also w=(1—v?).(v-+-v°-+-v9-013_.. ad inf.)
And w/=(v?—1).(v3--v7-+-vll-+-215__. ad inf.)
Then wary) wr ‘vad wep ae ao
ine value is positive, and shows that the rings by reflection at these thicknesses will be
right.
At the second surface, for the same thicknesses, we shall have,
u/==(1—v?).(1—v®-+ 0105... .ad inf.).
And, by proceeding as before,

(1°)
2-2’ =u'/——_ f
| ey
Showing that the rings scen at these thicknesses by transmitted light are obscure, but not
dark, because u’, which embraces all the light transmitted, Las still a value,

188 UNDULATORY THEORY OF LIGHT.

In the other case, it will be observed that the rays I and I’ undergo repeated
reflections between the surfaces of the plates—a
portion of the light escaping and being transmitted
at each reflection. If the plates are of perfectly
equal thickness and all the surfaces perfectly par-
allel, there will be no interference. Suppose, how-
ever, that one of them is slightly thicker than the
other. Then, if we attend first to the transmitted
rays, T’, T’, we shall see that the path of T, after
incidence and up to final emergence, is made up of
three times the thickness of the first plate, once
the thickness of the second, and once the distance between the plates. Put 6
for the first thickness, 0’ for the second, 6 for the distance between, and L for
the length of path. Then—

Fig. 9.

L=36--6!--o.

Tracing back 'T’ in the same way, and denoting its length of path by L', we
have—
L'=0+36'-+6.
Hence L’/—L=2(6’—0).

And when this value is so small as to be comparable to the absolute thicknesses
which produce the colors of Newton’s rings, similar colors may be seen here.

If we attend to the reflected rays R and R’, we shall see (employing the same
notation as before) that—

L==46--20.
L'=20+20'+20.
Hence L’/—-L—2 (0'—0), as before.

It will be noticed that there are other rays, as 7 and ¢, which do not form tints,
their differences of path, as compared with R, R’, or with T,'T’, being too great.

§. VII —POLARIZATION BY REFLECTION AND BY REFRACTION.

We will now proceed to give a physical theory of the phenomenon called
polarization of light, and of its production by reflection and refraction. It has
already been hinted that the phenomenon itself consists in the determination of
the molecular movements in the suecession of undulations which constitutes a
ray or beam of light, to one constant azimuth, or definite direction in space ;
those which exist in common light being distributed impartially through all
azimuths. In order to simplify the problem of the influence of reflection upon
molecular movement Mr. Fresnel commenced this investigation by consider-
ing first the case of a wave polarized already in the plane of incidence. In
such a wave the molecular movements are (for reasons which will appear here-
after) presumed to take place in a plane whch is at right angles to the plane of
polarization. At the reflecting surface, they are therefore coincident with the
surface itself. If the ray is passing from a medium of less refracting power
into one of greater, we must suppose that the ether possesses either a different
elasticity, ora different density, or both, in the two media. Mr. Fresnel assumed
a difference of density without a difference of elasticity. He assumed, secondly,
that in the common surface or stratum bounding the media, the movements
parallel to the surface are common to both media, so that the components of
velocity in the incident and refleeted wave, parallel to the surface of reflection,
are together equal to the component of velocity in the transmitted wave parallel
to the same surface. Or, if unity represent the incident molecular velocity, o

POLARIZATION BY REFLECTION. 189

that of the reflected wave, and w that of the transmitted wave, we shall have
the equation, 1+v=w
With these suppositions let Ie, Ie be the bounding
limits of a mass of the ether, along which an undulation
moves, meeting the reflecting ee MN ince. Let
ch, eR’ be the nannies of the reflected undulation, and
Cc 1 eT’ those of the transmitted undulation. Draw
ch, ef perpe ndicular to Je,cT. Let cd be the length
of the incident, and ef that of the transmitted undu-
Fig. 47. lation. Draw ad, gh parallel to cb, ef, respectively.
We may regard the incident undulation as a mass
whose bulk is the prism abcd, and de: isity d, impinging upon a mass w hose bulk
is efgh, and density 0’. Since the molecular movements in this case are im the
the common surface of the media, the dreadths of the prisms, according to the
second assumption foregoing, are equal to each other. Their lengths will be A
ane A’, and their depths be and ef. Or, putting m and m! for their masses,
:m!::bcX2x0: efi’ xd! Now, the wave lengths are proportional to the
Gace of progress of the wave in the two media a, (which we may denote by
Vand V’.) Hence, if we put + for the angle of incidence, and p for the angle
of refraction, we shall have, 4:4’::V: V’:: sine: sinp. Also, ech=:, and
cef=p ; from which we derive dc=ce.cost, and ef=ce.cosp. And substituting—

m:m':: sintcos:.d : sinpcosp.a’.

But, in the propagation of tremors through elastic media, the velocity of pro-
gress is directly as the square root of the el: asticity, and inversely as the square

root of the density. Or, putting < for the elasticity, v—<, and vem, ee be-
6

ing constant. Accordingly

td ‘
6:6'::=:=5; and, by substitution,
: V2 vy?
,_Sin:cost sinpcosp sinrcose sinpcosp cose cosp
m:m! ::——— : — 3 : : ;

VW Ne ogintt caine: sine ; Bing:

Now the living force in the reflected and transmitted waves must be equal to
the living force in the incident ; or—

mxV?=mxv*+m'xu*; that is,

cost Cos cos cos Os
oe a ee; or, (1—2?) OFF — CORP
sine sine sinp sine sinp”
From this, with the equation previously given, z= 1+, we obtain, by elim-
ination,
sin( — > 2cos:sinp \?
ee ae ey [19.] [20.]
sin( (¢-+p) sin(¢-+p)

If, in order to embrace in the formula only the angle of incidence, we elimi-
nate p from the foregoing by means of the equation sins—zsinp, we shall obtan—

by 2 ie SEY and v= Tee) PMR

V n?—sin2« + cose V n?—sine-+ cose

When the incidence is perpendicular, «= 0°, sins = 0, and cos:=1. In this

case, vaC— Sj) i and =(5)-

The intensity of light is measured by the living force of the molecular move-
ments, or by the mass multiplied by the square ‘of the velocity. As the mass

190 UNDULATORY THEORY OF LIGHT.

is the same for the incident and reflected waves, their intensities are as 1? and
v. When we compare the transmitted with the incident or reflected waves, we
B sais cose s ;
must consider the masses. By multiplyingv? by ——, and w? by ae, their
SSHssint sing
; COS? Laan 5 an
sum will be found equal to ——, which is mx 1?, or the living foree of the
sine

incident. wave.

: et cose cos ae :
For perpendicular incidence m= a and m!'= = become infinite; but their
sine - sing

ratio remains finite; and as they are not expressions for the absolute values of
the masses, but only of their relative values, their ratio only is needed. By
replacing sin: by its equivalent xsinp, we have—
‘1 (HOOBG. 1COSIor ye eOR?
m: Mm! 33-——3-—-- 31 -— 1 COse :: COSe: meOSe ;
asinp sine 7
which, when cos:=cos0°—cosp=—1, gives m:m'::1:n. And the sum of the
intensities at perpendicular incidence is—
(x—1)? dn (n+1)? f
——~, 2 == = go l=1xl’,
(a+1) (w+1) (+1)
which is the intensity of the incident wave.

If now we consider the gencral value of v?, given above, we shall see that v
increases with the increase of the angle of incidence, and becomes equal to the
total molecular velocity of the incident wave, when :—90°. For, at this inci-
dence, sin’: —1, and cose=0. Henec—

Shae
Vv ne—12

= -) == 1 s"and 27
Vv?—1

For intermediate incidence, we may transform the expression thus:

a ( V (x? — 1) +c0s*—coss y

Ixv?stnaxv’=

9

v=

V (ne? — 1)+cos*e+ cose-
The value of the radical diminishes with the increase of the incidence; but
. . ee . >a > a . . 2
it diminishes less rapidly than cose. For, the form of a binomial square being—
q g

a+ 2ay+y",
if we put 2ay4+y’—= constant, it is evident that as x diminishes, y must increase.
Fatting, therefore, cos: in place of a, we shall have—
cos’: + 2ycose+ y” = cos (n?—1),
or, 2ycost+y’=x’—1=constant ;

and as cose diminishes, the other part of the root of the radical increases, so
that the value of the entire radical diminishes less rapidly than cose. The
numerator ef the expression accordingly increases with increase of incidence,
and the denominator diminishes: and both these changes increase the value of
». Hence, the amount of light reflected increases from incidence —0° to inci-
dence —90°. It is worth observing that the expressions we have obtained
above for the molecular velocities of the reflected and refracted wave, are also
deducible directly from the ordinary formule for the impact of elastic bodies.
These formule, (employing m and m’‘ for the masses, as above,) are—

m—m' 2m
0 and w= Sar ae
m+n m—+m

If, in place of m and m’, we substitute the values found for the masses, viz :

mae, and m'="“, the foregoing formule will be reproduced.

sine sinp

POLARIZATION BY REFLECTION. 191

Let us next examine the case of a wave polarized in a plane at right angles
to the plane of incidence. In this case, the molecular movements are in the
plane of incidence. ‘The expressions for the masses will be the same as before ;
but the components of the molecular velocities parallel to the reflecting surface
are to'be taken, instead cf the velocities themselves. These components are,
for the incident wave, 1 Xcos¢; for the reflected wave, v’ Xcose; and for the trans-
mitted wave, w/Xcose : and the assumption of Fresnel is—

(1+ 0')cose= w/cosp.*

* Tn the attempt to apply the theory of undulation to the case of reflection and refraction
at the surfaces o: crystalline media, it has been found more satisfactory by Profs, McCullagh
and Neuman to employ the following assumptions, viz:

I. The vibrations of polarized light are parallel to the plane of polarization.

Il. The density of the ether in both media is the same as in vacuo.

III. The vis viva-is preserved.

IV. The resultant of the vibrations is the same in both media; and therefore, in singly
refracting media, the vibration of the refracted ray is the resultant of the vibrations of the
incident and reflected rays.

On these principles, the case of reflection in the plane of polarization is simp'e. Let the
refracted ray be extended backward, and it will divide the angle between the incident and
reflected rays (which equals 2c) into two parts, which are, respectiveiy, :++p and c—p. Upon
this retroduced line as a diagonal, if a parallelogram be constructed with the incident and
reflected rays as sides, this diagonal and these sides will be proportional to the amplitudes,
and therefore to the velocities, of the mo'ecular movements which are perpendicular to them
severally. Employing then, as before, unity and the symbols v and wu to designate these
velocities, we shall have directly—

sin(c—p) sin2z
== — =, w=...
sin(t+p) sin(t+p)

In the case of reflection in a plane at right angles to the plane of polarization the vibra-
tions are al] parallel, and the fourth principle above gives—

1+-0'=w’.

Also the third principle gives (m and m’ representing the masses of the ether put into mo-
tion in the contiguous strata of the two media)—

m(1—v’?)—m'u'®,

These equations lead to the values—
m—m' 2m

/ /
v=- . i=
mem’ m—en’

The same values may also be deduced from the laws of impact of elastic bodies

According to the second principle, the masses m and m‘ ure proportional to their volumes ;
and these volumes have been found in the text to be proportional to sinzcose and sinp cosp.
Substituting these expressions in place of m and m’ in the foregoing fractions, we shall
obtain—

2sin@e

C ~ tan(e-+p)’ e ~ sin(i+p)cos(e—p) tan(¢-+p) coszu-+-cos2p)

‘ Comparing these values with those of ihe text, we find those or v alike, but with reversed
signs and interchanged—that which represented the velocity of molecular movement nor-
mal to the plane of polarization before, now denoting the velocity of movement in the
plane, and v.v. In the expressions for the transmitted rays there is a difference which
results from the adoption of the second of the principles foregoing, making the densit of
the ether in the two media the same, which is not the supposition of the text. Z

However strongly on some accounts this view of the subject may seem to recommend
itself to our accepiance, it introduces a difficulty (elsewhere noticed) into the theory of double
refraction, which has never yet been met, and which scems to have been singularly ignored
by many who have engaged in this discussion. 7 hee

In order to facilitate the comparison of the values of the several expressions foreroine
they may be reduced to a simple form of common denominator, when they become— eee

1. For the case of vibration in the plane of reflection—

,__tan(¢—p) } sin2

___ sin2(t—p) __ 2sin2vcos(t—p)

~ sin2c+sin2p° ~ sinze-fsindp
2. For vibration normal to the plane of reflection—

,__Sin2i—sin2p ,_____ 2sin2e

eee TEA CC eae DES E
sin2v-++ sino sin2i-++sindp

192- UNDULATORY THEORY OF LIGHT.

Combining this with the equation of living forces given above, and reducing,
we obtain ficce results :

py ae an(t—p y. ai =(, __ 2cossinp —__ z 3
C entra) nd = ( ea Petes

Replacing, as before, the value of sinp by its equivalent derived from the
equation sint—=zsinp, we arrive at the following values which embrace only one

variable:

V 72 —sin®: — n2e0sc)\2 2cOst 2
- = ee) ; and wz? = ——— —). [25.] [26.]

V 2 —sin®e-+ n2cose V n2—sin®:-+n2cose

The following forms are convenient for discussion :
1. For vibration in the plane of reflection—

__ RCOSp—COst ee 2ncost
neosp-+-cose ncosp--cose
2. For vibration normal to the plane of reflection—
nCOSt—COSp ;__ Sncose
~ neost-Lcosp’ ~ neost--eosp"
At a perpendicular incidence cose—=1 and cosp=1. Hence, in both cases,
n—I1 2n
=——, and u! = ;
n+ n+

Thus z and w’ will always be positive, and v and wv’ will be positive when » is greater than
1 and negative when 2z is less than 1. This ought to be so, according to the laws of mpae*
of elastic bodies, because, the density of the ether being by hy pothesis the same in both
media, the masses iepcting ¢ on each other will be as sine to sinp, or as to iH

As the incidence inercases, the variations of the value of v and v’ will be dissimilar.
When vib.a.ion is in the plane of refiection and n exceeds unity, the positive term ncosp
is necessarily aways meater than the negative term cose. Both these terms diminish as ¢
increases. If they dinumished at the same rate, the value of v would be constant. But
as 4 is always giecater than p and neither excee ods 90°, the rate of diminution of cose is more
rapid than iha: of cos :p, and the value of v increases with the incidence. The same is true
when z is less than unity; only in that case the increasing value of v is negative. When
the incidence is maximuni, or -=9L°, x being greater than 1, cose=0 and v=1; that is te
say, the reflected is equal to the incident light.

For the ainownt transmilicd in the same case, we have, at a perpendicular incidence—

. Qn
al
And for 1=90°, or the maximum incidence, 2 beine greater than I
? Bs Ono ’
u=0.

It is also apparent that the amount transmitted constantly diminishes as ¢ increases.

When vibration is normal to the plane of reflection, the positive term in the value of 7’,
which is neoss, is at fils gieater (2 being greater than unity) or less (7 being less than unity)
than the negauve term cosp. But since at the maximum incidence cosi=0, there must be
some value of ¢ which wvl give ncosi=cosp, or ncost—cosp=0. Accordingly, at this inci-
dence no light wi:l be reilected.

The two conditious—

ncosi==cosp, and nsinp=sinz,
give immediately—
sinp=cosl, or 1-+p=90°.

The incidence ¢ is the polarizing incidence; and we here sce that it fulfils the law of
Brewster.

At the maximum incidence, n being ae than 1, v‘=—1. The sign of the molecular
movement, therefore, changes at the polarizing angle.

The transmitted hight is im this case, at the perpendicular incidence,

) en
w= ;
n--1
And at the maximum incidence,
u'=0,
At the polemaie incidence, where, as me have just seen, coso=ncost,
NCOSL

/—

ncosi--ncost

POLARIZATION BY REFLECTION. 193

If we suppose the incidence perpendicular, we shall have, as before,

Aye BV ate ae ;
‘—_ — ) , and w?=€ - ) . Aft incidence 90°, we have again,
a+1 a+1.
Ree
Vn? —1
a v=) = 1s 9nd w=),
Vne—1

The agreement of these formulas with those obtained in the other case, is
what ought to be expected, since, at a perpendicular incidence, the direction of
molecular movement can have no influence on reflection; and at 90° impact ceases.
But if we examine the first value of ov! given above, we shall perceive that it
does not constantly increase with the increase of the incidence ; for the denom-
inator, tan (t+), becomes infinite when ¢+-+p—=90°; and at this incidence »/~0,
or there is no reflection. If then, in the originally incident beam, there had
been a succession of waves, some of them polarized in the plane of incidence,
and the rest polarized at right angles to that plane, all this latter class of waves
would, at this particular incidence, be transmitted, while a portion of the others
would be reflected. The incident light, from the mixture of the two classes of
waves, would be imperfectly polarized, or not polarized at all: but the reflected
light would be wholly polarized in the plane of reflection.

In the result just reached, we see a reproduction of the law experimentally
established by Brewster, viz., that, at the polarizing angle, the transmitted ray
is at right angles to the incident ray, or -+p—=90°.

If we now take the case of a wave whose plane of polarization is in any azi-
muth to the plane of reflection between 0° and 90°, we may apply the principles
already illustrated, by decomposing its molecular movements into components,
one of which shall coincide with the plane of reflection, and the other with the
reflecting surface. If the given azimuth be a, the azimuth of the molecular
movements will be 90°—a. ‘Phe molecular movement in the plane of reflection
will therefore be cos(90°—a)—=sina ; and that in the reflecting surface will be

That is to say, at this incidence the entire molecular movement normal to the plane of reflec-
tion is transmitted.

In this case the condition 14-v'=w' is always fulfilled. When vibration is in the plane of
reflection it is fulfilled only for the perpendicular incidence. At other incidences the fourth
principle of McCullagh and Neuman, quoted above, necessarily involves the truth of Fresnel’s
assumption for this case, viz:

(1++v')cosi=w'cosp.

When x is less than 1, these formule fail for incidences beyond the limiting angle of total
reflection. : ;

The formule in the text admit of reductions similar to the foregoing. They thus become—

J. For vibrations in the plane of reflection—

sin2v—sin2p Asinpcose
nr Mereteene ip Pexeicay se aa ei ee .

sin2c-+sin2p sin2c-+sin2p
2. For vibrations normal to the plane of reflection—

.

sf

SEI Mapp, @ 31a epee Oster pe)

~ sinQe-fsin2p" sin2v+-sin2p
And for convenience of discussion:
1, Jor vibrations in the plane of reflection—
_____"cost—cosp pas __ 6 COSe
neosi--cosp ncosi--cosp
2. For vibrations normal to the plane of reflection—
NCOSP—COSL 2COse

— /

3 y= ———_ —
neosp--cose ncosp--cose

‘The first of these values of © becomes zero at the polarizing angle, and is positive for all
higher incidences,

13s

{QA UNDULATORY THEORY OF LIGHT.

cosa. The living force in the reflected beam (which we oh repuesent by R)
will consequently be—the mass ae assumed for conv

sin(t—p)\? tan(¢ =P) ls
r= ) .cos’a + ) sin?a. [27.]
sin(¢+p) tan(¢+ p)
‘The agreement of this result with our previous conclusions may be verified
by making @ successively 0° and==90°. In the first case—

2
sln(¢— : tan(¢—
Hie ( ( =e) ; and in the second, R= eae ( sy,
; sim(¢-++ p) ‘ ; tan(¢-+p)
If a== 45°, sin’a= 4, and cos’*a=4. Consequently,

eee (ase A, ey [28.}
Ls aa ) cece ‘ 20.
“& Asin(¢+ p) tan(¢+) :

This might easily be anticipated by considering that, in the supposed oo
the incident beam is equivalent to two beams, each having an intensity of 4,
and polarized—one in the plane of reflection, and the other in the plane perpen-
dicular to it. he reflected beam should contain one-half the force in each
plane which it would have done had each intensity been = 1.

Let there now be two beams each ==4, incident together, and polarized in the
azimuths a and a’. From what has just been said, it is evident that the value
of R will be—

9
sin No . is tan(¢—p
ia (= a me .(cos?a+cos*a! ) +3{ (= e)y’
sin(¢+p) tan(: +p)

In this expression, if a/=90°—a, cos*atcos’a'=1. Also sin?atsin?a’=1.
R becomes, therefore, equal to the sum of the intensities of two rays each —$,
polarized, one in the plane of incidence, and the other at right angles to it, ne
matter what may be the value of a. If, then, any number of waves, in different
azimuths, follow each other in so close succession as to blend their impressions
upon the eye, and if their azimuths are so impartially distributed that for every
value of « there is another = 90°—a, the forces in all these azimuths being
equal, then the resultant effect of the whole must necessarily be—

sin(t—p)\”__, stan(t—p)\? :
lace) +2 ey =a [ 0.

But this is the condition of common light. The formula just stated, there-
fore, represents the living forces in the two principal planes, in a beam of com-
mon light after reflection, the original force being taken == 1. When ¢4-p=90°,
the second term disappears. The reflected'beam is then entirely polarized.

It we decompose the second term in the value of R, above, into its factors,
we shall have (disregarding the numerical coefficient, and omitting the expo-
nent)—

0 .(sin?a + sin?a’). [29.]

ps

ie

tan(:—p) __sin(¢«—p) cos(¢+p) [31.]
tan(¢-+p) sin(s-+p)" cos(t—p) * ;

The molecular velocity of the wave polarized at right angles to the plane of
reflection appears thus to be equal to that of the wave polarized 7m the plane of

cos(¢-- 0)

reflection, multiplied by the factor —— i

cos(¢—p)
est value it can have) the numerator and denominator of this fraction are equal,
with opposite signs. The sign does not concern us at present, as it has no effect
upon the value of the living force in the wave. For all values of ¢ less than 902
(y being necessarily less than « when exceeds 1 1) the denominator is greater
than the numerator. It follows that in the reflection of common light, a larger
amount of living force will, in the reflected beam, be preserved in the movements

Wher ¢==90° (which is the great-

POLARIZATION BY REFLECTION. 195

perpendicular to the plane of reflection than iv those coincident with that plane;
or, in other words, that the refleeted beam will be more or less polarized in the
plane of reflection.

In order to estimate the amount of this polarization, we must take the differ-
ence between the two terms in the value of R. And if we desire to find the
proportion of light polarized, we must divide this difference by the sum. Or
putting P to represent this proposition :

cos*(‘+p)'
a ‘

. sin?(:-+p) j __ cos*(t—p)—ceos?(¢t+p) ae
~ sin’(:—p) (1+ cos*( tp cos*(¢—p )reos"( «tp ) [32]

cos? t—o

gin?((—p
sin*(¢ p) (1

sin?(¢+p)
Reverting once more to the case of a wave polarized in azimuth a to the
plane of reflection, we shall perecive, by the formule, that after reflection it is
still polarized, though not in the same plane as before; for the rectangular
components of the molecular movement being unequally altered, their resultant
must have a new direction. In the expressions,

cos*(t—p)

tee Soe)
sin(t—p) tan(ec—p) . sin‘t—p) cos/t+p
—=_| —————.. c08 a, v/==_. cect) Sirgela ee Ry EN +p)
sin(e-+p) tan(¢+p) “sin(t+p) cos(t—p)

the first is the molecular velocity normal to the plane of reflection, and the
second is the same velocity zz the plane of reflection. The second divided by
the first is therefore the tangent of the inclination of the molecular movement te

the normal; or of the resultant plane of polarization to the plane of reflection.
Putting this inclination = a’, we have

_ sina.

sing eos(t--p cos(¢+
fang == y see) ee B\ py [3334
COSa COs(t—p) cos(t—p )
If the reflected ray undergo reflection from a second mirror parallel to the
first, its incident azimuth will be a’; and, after reflection, it will have another
azimuth @”, of which the tangent will be

, cos/t+tp) cos*(¢+p)
tana’—=tana’. +"? =tana,— >. [34.]
cos(t—p) cos?(t—p)
And, as the law is manifest, we may say that after any number, x, of reflee-
tions, the tangent of the azimuth will be

tana —tana (

While cos(:-+p) has a value—that is, while :+p is more or less than 90°—
tan™a will also have a value; or the plane of polarization of the wave will
not be brought, by any number of reflections, into absolute coincidence with the
plane of reflection ; but when ¢+p==90°, it will be so by the first reflection.

cos((+p) . ‘

When ee is a small fraction, or at least not a large one, the plane of

polarization will, after a few reflections, be brought sensebly into the plane of

reflection. For instance, let ¢ be 45°, and also a==45°. ‘Then, for glass
cos

tty will be about 3 In this

ey [35.]
SSS Sone ov.

cos(t—p)

(index 1.50) p will be 28° nearly; and : 7:

cos(t—p
case one reflection wi!l reduce the azimuth to 16° 42’; two to 5° 9’; three to
1° 32’; four to 0° 28’; and five to 0° 84’.

196 UNDULATORY THEORY OF LIGHT.

§ VIIL—CIRCULAR AND ELLIPTICAL POLARIZATION BY REFLECTION.

In all that precedes it has been tacitly assumed that the initial phase of the
reflected undulation is a continuation of the final phase of the incident, or of
the same reversed ; and also that the virtual origins of the elementary waves of
which we suppose the resultant refle;.ed wave to be composed, are in one tiva-
riable surface, whatever be the azimuth of the incident molecular movements.
If these assumptions are entirely true, the expressions for the molecular velo-
city of the reflected wave ought to correspond with observation in all cases.
‘These expressions, nevertheless, fail for the case of total reflection at the second
surfaces of denser media, as will be apparent if we substitute the value of x,
which, in the cas¢ supposed, is less than unity in the formule.

== | —____—.

V n2—sin®:-+ cose

When sin®: x”, v? and v? each == 1; or the reflection is total. We know,
experimentally, that it continues to be total for all higher values of ¢; but the
radicals in the foregoing become imaginary. Mr. Iresnel, therefore, concluded
that reflection in some manner modities the phase of the undulation. Experi-
ment proves that it does so, and also that the degree of the modification depends
upon the azimuth of the molecular movements, and upon the incidence.

The conversion of plane into circular polarization by reflection in “ Hresnel’s
rhombs ” has been deseribed. ‘Che manner in which this change takes place
may now be understood. If the plane ray is incident in either of the principal
azimuths 0° or 90°, its plane of polarization is not affected by reflection. But
if its azimuth be 45°, it emerges from the rhomb after having undergone two
total reflections circularly polarized. Now the plane polarized ray in azimuth
45°, is equivalent to two plane polarized rays of half the intensity in azimuths
0° and 90.2 And as these components would singly undergo no sensible
change of plane by reflection, while jointly they produce a circularly polarized
ray, we infer that one of them has been advanced or retarded upon the other
by a quarter of an undulation. If the ray had undergone only one reflection
in the rhomb, or if it had undergone three, it would have emerged neither plane
polarized nor circularly polarized. If it had undergone four, it would have
emerged plane polarized again, with a change of 90° from its original azimuth.
Now, all these phenomena are represented by the equation [1] for the resultant
of vibrations at right angles to each other, which is as follows :

9 ay 2
z = aS nen a “as ql?
?

a

V n2—sin2:-+-n2cost

ay? +ara’—2aa'xycos0=a" asin".

If we substitute for 0, which is the interval between the two compounded
; ; hiss : h ;
undulations, the more convenient symbol ans in which 7 expresses the differ-

ence of phase as a fraction of an undulation, the equation takes the form,
5 th be es h che h
aly’-a'x —2aa'rycosen, =a a'sin2n— ‘
. “a . , . . ;
This equation becomes the equation of a circle if we make a—a’, and

h
A

=}, or an odd multiple of 4. It is then a’+y?—=a’. It is the equation of an

: ; Leeks. 5
ellipse for any values of 7 if ais nota’. Hence the necessity of the con-

dition that the original plane of polarization should be in azimuth 45°, that the
components into which the velocity is decomposed in the principal azimuths

. . u} . “fp h s
may be equal. It is an equation of an ellipse when a=a’, if 7 is not == 4,

: 2 , a re
or an odd multiple of 4. The ellipse becomes a straight line if {hh or an odd

CIRCULAR POLARIZATION. 7%

multiple of 4. It is therefore evident that, at each reflection in the rhomb, one
of the component waves is accelerated or retarded one-eighth of an undulation
upon the other.

The restoration of the plane polarization, after four reflections, in an azimuth
90° removed from the azimuth of incidence, may be understood by considering
the following illustration. Let the
arrow PP’ represent the amplitude
of movement in a polarized wave at
a given moment. Let this be re-
solved into two rectangular compo-
nents 45° inclined to it on each side,
represented by the arrows QQ! and
RR’. Suppose the molecule, at a
given instant, to be situated at the
point C* of its path. CP’ is the direction in which it is moving, and the length
of the line is the extent of its range. By two reflections in Fresnel’s rhomb,
or by any other cause, let the component IRR’ be so advanced upon QQ! that,
at some future instant, the molecule shall have reached the limit of its range in
the horizontal direction, and shall be about to return (as at R in the second
system of arrows) when, in the vertical direction it is in the middle point, and
going toward Q'as before. This would be in CO’, but for the horizontal displace-
ment. In point of fact, it is at It. The vertical velocity, (represented by the
dotted arrow Q’Q',) is at its maximum, and the horizontal velocity is zero.
‘The conditions are such as, in the section on vibration, are shown to produce :
revolution of the molecule in a cirele. The path of the molecule will accord-
ingly be RQ’'R’Q. After two additional reflections in the rhomb, the horizontal
movement will be advanced over the vertical by another quarter of its double
vibration, and will bring the molecule, in its progress from right to left, to the
middle point, C", in the third system of arrows, at the same instant at which
the vertical movement, in the direction Q’, brings it to the same point. The
velocities are now both at their maximum, and are equal. The molecule takes
the mean direction, PP’, between them, and the ray is plane polarized in an
azimuth 90° from the original plane.

Suppose the eye of the observer to be at E, the revolution of the molecule is
dextrogyre, or, as it is also called, dextrorsum. Conceived as viewed in the oppo-
site direction, it would be levogyre, or sinistrorsum. In the earlier history of
this subject, some confusion arose from the fact that different observers applied
these terms in different ways. Since observation, however, is only made upon
rays approaching the observer, this is the point of view now universally adopted
in naming the direction of gyration. It appears, then, that the advance of the
left-hand component, by a quarter undulation, produces a dextrogyration, and
vice versa. If the plane of original polarization were P’P’”, then, iv the resola-
tion, RR! would be reversed, and the advance of RR’ would be the advance of
the right-hand component, producing levogyration. In this case, after four
reflections in Fresnel’s rhomb, the resultant plane of polarization would be PP’.

If we distinguish, as positive, the azimuths to the right of the plane of reflee-
tion, and, as negative, those to the left, we may say that a plane polarized ray
in original azimuth —45°, is circularly polarized dextrorsum by passing through
one of Fresnel’s rhombs; and becomes plane polarized again in azimuth + 45°,
after passing through two. If the original azimuth be +45, the circular polar-
ization is sinistrorsum, and the final azimuth of plane polarization, negative.
One of these rhombs may, therefore, be used as a polariscope, to detect the
direction of rotation of a circularly polarized ray.

If two rays, one in azimuth +459, and the other in azimuth —45°, were to
be reflected simultaneously in one of Iresnel’s rhombs, the two consequent

big. 48.

*The letters C, C’, C’’, are accidentally omitted from the diagram. They should be placed
ou the dotted Jine at the intersections of the successive systems of arrows.

198 UNDULATORY THEORY OF LIGHT.

gyrations, being in opposite directions, would produce a rectilinear resultant. In

; this case, suppose the molecule, M, to be in any part of the
circumference in which either of the gyrations would cause
it to revolve; it will be subject to the action of three forces:
one, MC, directed toward the centre of its orbit, and the
other two, represented by P and Q, equal and opposite. The
two latter neutralize each other, and the molecule pursues the
path MC. When the molecule is at M’, the tangential forces
P and Q, which will then have the directions P’ and Q’. will
not directly balance each other, but will have a resultant in
the direction RC. And for all other points in the path of
the molecule, as M"’, M’’, &c., the resultant of the tan-
R eential forces will always be in the diameter, MN, of the

Fig. 49 orbit.

In Fig. 48 we have supposed the arrows PP'and P’'P’” to represent not only
the positions of the planes of molecular vibration, but the direction of the move-
ments. heir resultant plane is accordingly QQ’. If the direction of one of
them, as of P’P”, had been opposite, the resultant would be RR’. If the two
were in any equal positive and negative azimuths, greater or less than 45°, their
resultant gyrations would be elliptic; but the ellipses, being equal and similar,
and similarly situated to the plane.of reflection, while they are opposite in move-
ment, would still produce the vibration QQ. And two movements in azimuths
equally above and below 909, cither positive or negative, would in like manner
produce the plane vibration RR. Now the condition of natural light is such
that, for every azimuth of its successive plane vibrations, as PP, producing, by
total reflection, a gyratory molecular movement, whether cireular or elliptic,
there will always be found another which will produce an equal and opposite
gyration. And, although these gyrations are successive and not simultancous,
though, therefore, there is never, in this case, any real composition, like that
illustrated in Fig. 49, neutralizing, im fact, the gyratory movements, yet the
compensatory effects follow each other with such rapidity that, to our instru
ments and our powers of vision, they are as if they did not exist. Common
light cannot, therefore, be polarized by total reflection. Moreover, common
light need not, in any case, be supposed to be made up strictly of plane. vibra-
tions. It is only necessary to suppose its gyratory movements to be as impar-
tially distributed as we have heretofore presumed its plane vibrations to be.

If, however, we suppose a surface which is not a surface of total reflection to
possess the power of accelerating or retarding one of the rectangular components
of the incident molecular velocity over the other, then the reflected light will,
in general, be elliptically polarized. For the two components are never equally

efleeted except in total reflection. Now there are very few substances capable

of reflecting light which do not possess this power, and, accordingly, ellipticat
polarization is the effect most usually attending reflection. As has been else-
where stated, it is only those substances whose indexes of refraction are very
near to 1.414 that produce a kind of polarization that is sensibly plane.

This subject has been very thoroughly investigated, theoretically, by Mr.
Cauchy, and experimentally by Mr. Jamin, with results mutually corroborative
of each other. In order to clearly understand the experimental methods
employed, let us observe that, if a plane polarized wave be supposed to be
decomposed into two rectangular component undulations, the curves represent-
ing these components will cross the common intersection of their planes in the
same points. These crossing points may be called nodes. In the case sup-
posed, the nodes of the two components are coincident. ‘The effect of reflection
is, in general, (2. e., in all cases except those which have the index of refraction
just now mentioned,) to throw the nodes of the components out of coincidence.
And the original plane polarization will be restored by bringing back the nodes

CIRCULAR POLARIZATION. 199

to their original coincidence, or by encreasing the discrepancy between them by
repeated reflections until it amounts to half an undulation. In the first case, if
the reflection were total, as at the second surface of glass. the plane of’ polari-
zation, after restoration, would be unaltered. In the second case, on similar sup-
positions, it would be changed 96°, When the reflection is not total, the
resultant plane, after the reunion of the displaced nodes, will differ from the
original plane in consequence of the unequal losses experienced by the two com-
ponents in reflection.

Both those methods have been employed in experimentally determining the
dislocating effects of different media, at diiferent incidences, upon the rectangular
components of plane polarized light. Many of Mr. eal $ more recent and
élaborater -esearches have been made by the method first meationed. The esseatial
part of his apparatus consisted in a double prism, formed of two equal acute
wedges of rock crystal, cut parallel to the axis, and combined as shown in the
figure annexed. The wedge ABC has the edge AB par-

iP, LB
Pi Fi A allel to the axis, and’ the wedge ADC has the edge DC
A i $$ 2B perpendicular to the axis. The surfaces AB and DC are

both parallel to the axis. If a plane polarized ray, PQ,

C pass at right angles to AB through the middle of this

Dipl lipase.
a gi system, W here the wedges are equally thick, it will remain
Qi plane polarized, and the position of its plane will remain
Fig. 50. unaltered whatever be the azimuth of incidenec; the dis-

locating effect of the double refraction of one of the wedges being compensated
by an equal and opposite effect of the other. But if the system be moved
the right or to the left, the two opposite effects will no longer be equal. This
being a positive e crystal, the component of molecular movement parallel to AB
will be in retardation of that perpendicular to AB, for the position of the ray,
P/Q’. and will be in advance tor the position P'Q’. But if the ray has been
alr ready dislocated by reflection, some part of the prism may be found which
will produce an equal and contrary effect, so as to restore the plane polarization
All that is necessary, then, to make this instrument a measure of the dislocation
is to connect it with a scale and a screw movement, and to determine the value of
the seale divisions. This last determination is easy. since a run which converts
a plane polarized ray into a ray plane polarized with a difference of azimuth of
90°, is equivalent to half an undulation. Mr, Jamin’s apparatus accomplished
this change in twelve complete turns of the screw. Smaller divisions were
measured by the graduation.of the serew-head, of which there were two hun-
dred divisions to the revolution. he deli icacy of the contrivance may be appre-
ciated from this statement. It is known as Mr. Jamin’s “compensator.”

It would occupy too much space to attempt here to give a full account of Mr.
Jamin’s interesting researches, or of the methods employ ed by him auxiliary to
that just described. The most important results of his investigations are the
following :

Nearly all transparent bodies produce, by reflection from their surfaces, a
difference of phase between the component waves polarized in the two principal
planes. All whose indexes of refraction exceed 1.414, advance the phase of the
component polarized in the plane of incidence. All those whose indexes are
below that value retard the phase of the same component.

The difference of phase augments with the incidence from 42 at 0° to 4 at
90°, and becomes #4 at the polarizing angle. The variations are slow and
almost insensible for some distance from either 0° or 90°. They usually become
sensible near the polarizing angle. ‘The limits are nearer together as the polari-
zation under that angle is wreater.

Beyond these limits the polarization is plane, but imperfect. Within them it
is elliptic.

The two limits are nearer to each other as the index of refraction approaches

200 UNDULATORY THEORY OF LIGHT.

1.414. They wnite, for substances whose index has that exact value. Mr.
Jamin found but two substances in which this condition is falfilled. They were
a specimen of menilite, and a crystal of alum cut perpendicularly to the axis of
the octahedron. Water and glass, which under ordinary light appear to polarize
perfectly, are easily seen not to do so under the strong light of the sun.

In the cases in which the index has the particular value just mentioned, the
advance of phase at the polarizing angle is “brusque” from 4A to 2. This is
very nearly the case with water and glass.

teflection from the surface of metals always produces elliptical polarization.
‘The advance of phase is progressive from incidence 0° to incidence 90°. 'There
are, however, very large differences between metals in this respect.

§ IX. ROTATORY POLARIZATION.

We are now perhaps prepared to understand the reason of the rotation of the
plane of polarization of a ray transmitted along the axis of a crystal of quartz.
We have seen that Fresnel, by an ingenious combination of prisms, succeeded in
demonstrating the existence within the crystal of two cireularly polarized rays,
gyrating in opposite directions. And we have seen that the resultant effect of
two opposite gyrations is to produce a movement in a plane. ‘Phe gyratory
movements within the crystal are then not actwal but virtwal—in other words
there are forces constantly tending to produce these gyrations, which hold each
other in equilibrio or at least nearly so. We must consider these forces as suc-
cessively traversing all azimuths within the length of each undulation. If the
wave were of the same length for both gyrations, the forces being presumed
equal, the molecular movement would be constantly rectilinear, and the plane
of polarization would not change. But, as the plane does in fact change, we are
led to infer that the undulation lengths for the two rays are ot equal. The
annexed figure may serve to illustrate the mutual action of
these rays. Suppose MADB to be the orbit in which a
force P tends to urge a molecule, M, to revolve around the
centre, C, to which it is drawn by the foree MC. Suppose
the equal force Q to urge the same molecule to describe the
same orbit in the opposite direction. 'These forces holding
each other in equilibrio, the molecule will follow the direc-
tion of the third force, MC.

Now suppose the force Q suspended, the molecule will
take the direction of the circle ADB, and will continue te
revolve in it so long as the force P (supposed always tan-
gential) continues to act. But its movement will impart to
the molecule next below it a similar motion, and that to the
next, and so on; so that, as these successive molecules take
up their movement later and later, there will be a series in
different degrees of advancement in their several circles,
forming a spiral; and when the molecule M shall have
returned to its original position, the series will oceupy a position like the curve
MEFLN‘OR. If now P be supposed to be in turn suspended, while the force @
continues to act, the effect of @ will be to produce a contrary spiral, which may
be represented by MSKTV. If MD be a diameter of the circle MADB, drawn
from M, and DNHN’ be a line parallel to the axis CG of the cylindrical surface
which is the locus of the spirals, then, if the undulation lengths are the same
for both movements, the two spirals will intersect DH in the same point, the
intersections marking the completion of a half uadulation for each. But if these
lengths be unequal, the intersections with DH will take place at different points,
as N and N’.

Let now a plane intersect the cylinder at any distance below MADB, as at

INDEX OF ROTATORY POLARIZATION. 901

FE, parallel to MADB. It is conceivable that this plane may be made to pass
through the point where the spirals intersect each other. If I mark the point
of intersection, and we draw the tangents IP’ and 1Q’ in the plane of the circle
LHI, then there will be a molecule at the point I which will be in the cireum-
stances of the molecule in Fig. 49 at the point M—that is to say, solicited by
three forces, of which two, IP’ and IQ’, are equal and opposite, and the third is
directed in the line 1G toward the centre. The molecule will, therefore, move
in this line, and not in a circle; and if the plane of the cirele EHIH’ be the
bounding surface of the crystal, or the surface of emergence of the light, IG will
mark the azimuth of the molecular movement of the emergent ray.

But if the plane of KHIH’ do not pass through the point of intersection of
the spirals, it must cut each spiral in a different point. ‘The figure is drawn to
represent this more general case, the points of intersection with the spirals being
severally Land K. By joining LK, and drawing the radius GI perpendicular
to it, GI will bisect the angle LGK, and M’, at the intersection of GI and LK,
will be the position of the molecule in the plane EHLIK, which, if the tangen-
tial force P only were acting, would be at L, and if the tangential force Q only
were acting, would be at K. The tangential forces acting at the moment on
this molecule will not be represented by IP! and IQ’, but by tangents at K and
L, like RP’ and RQ’ in Fig. 49, in which figure the position of the molecule M’
corresponds to that marked by the same letter in the present figure ; but in that
figure the resultant of the tangential forces is RO, directed to the centre, and in
this it will, in like manner, be IG.

Now, as DH, the distance between the planes ADB and EHLI, is a larger
art of the length of an entire turn of the spiral MSNK than of the spiral
{i LN’, the line GI will fall on the right of GH, the position it would

oceupy if the two undulations were equal in length. We may therefore say, as
before, that if the plane EHI were the surface of emergence of a ray from a
crystal, in which it had been subject to the action of the forces supposed, its
plane of polarization, GI, would be turned toward the right from its original
azimuth. ‘The plane of polarization turns, therefore, in the direction of the
winding of the closest spiral, or of the ray of shortest undulation; but it turns
in the direction of the gyration of the ray of longest undulation.

This rotation of the plane thus demonstrates that the two rays advance with
unequal velocities in the axis of quartz—a remarkable fact which is not true of
any crystal which produces plane polarization only.

It also enables us to determine the relative velocities, or to ascertain the index
of rotatory polarization. For since GI bisects the angle between the points K
and L, which mark the relative degrees of advancement of the two rays in their
respective rotations, if we take a thickness, 0, which produces a rotation of 90°,
we know that the difference of phase is then one-half an undulation. If 4 de-
note the length of the longer undulation, and /’ that of the shorter, then—

9
0=mi=(m+ 4)’; or Ze: aonen zie ;
A m 2m

0 : ; :
As ym and A may be determined by experiments on refraction, the value

of mis known when @ is measured. By pursuing this method, Mr. Babinet
found the value of —==1.00003; a value which, small as it is, is the largest
a

known for rotatory polarization. :

When light is transmitted through quartz at right angles to the axis, the
emergent rays are plane polarized. My. Airy has proved that, for directions
oblique to the axis, the polarization is elliptic, the ellipticity increasing from
the direction perpendicular up to the direction parallel to the axis, where it
becomes circular.

202 UNDULATORY THEORY OF LIGHT.

It is dificult to conceive exactly the physical action by which rotatory polari-
zation is produced. But there is no difficulty in imagining such a decomposition
of the molecular movements ina plane polarized ray, as shall represent the
relations which exist after the rotatory polarization has been established. We
have seen that when a plane undulation has been resolved into two equal rectan-
gular components, if the nodal joints of these components become dislocated by
a quarter of an undulation, the resultant will be a movement in a circular orbit.
We have also seen that when the left-hand component is advanced by this
amount, the motion becomes dextrogyre; and whea the right-hand component
is advanced, it becomes levogyre. In order, then, to explain the co-existence
of two opposite circular polarizations, we must suppose two sets of equal
rectangular components dislocated in these two opposite ways. This was the
hypothesis of Fresnel.

In order to facilitate the conception, suppose the arrow P to represent, in
quantity and direction, the molecular movement, at a given instant, in the origi-

nal plane polarized wave. Imagine it to be
R aresultant of two other waves, Q and R,
one in front of it, and the other behind it,
reach at the distance of one-eighth of an un-
dulation. ‘these will then be a quarter of
an undulation distant from each other. Let
yi Q@ and R be again resolved, each into two
‘i equal rectangular components, in azimuths
Fig. 52. +45° and —45°; Q, into g and7; and R
into g’ andr’. Consider all these four component movements, at the instant
supposed, and in the positions represented, to be at their maximum of velocity,
in the direction of the several arrows denoting them. Then, if we consider the
relative stages of advancement, or phases of: movement, of the pair g and 7, in
respect to g/ and 7’, when both are referred to a common plane, it will be seen
that the latter, though most advanced in position, are least advanced in phase
For, if we conceive the curves of these waves to be drawn, the ascending node
of g’ will be found in the plane of gr, and the descending node of q in the plane
of q'r’. Hence, at the point where the wave g! begins, the wave g is one-quarter
advanced.

We have, then, two pairs of plane undulations, g and 7’ and 7 and q’, severally
normal to each other, and with nodes dislocated to the extent of one-quarter of
an undulation; g and 7 being the members of the pairs which are most advanced
in phase. In the case of the pair g and 7’, the right-hand component being that
which is most advanced, the resultant movement is a revolution sinistrorsum.
In the case of 7 and gq’ the resultant will be a revolution dextrorsum.

The values of these several components are determined from the general
equation following, which is simply equation [3,] with the symbols changed:

P*=Q7-_ RR? 20 eos’:

By hypothesis R=Q, and 6—90°. Hence P?==2Q?, and Q=55
i 72 Q ie
Again, Q@—=¢7’+7=2¢*. And i sm sue
R P
Also, R2==q?+47?—2q?. And g!’—=—-—=———-=3P.
a: . te v2 vev2 *

It appears, therefore, that the molecular velocity in each of the component
waves 4,7, q',7', is equal to one-half that of P, as it should be, in order that the
sum of their living forces may be equal to the living force of the primitive wave.

Since the two circularly polarized rays in the axis of quartz have unequal

INTERFERENCES OF CIRCULARLY POLARIZED RAYS. 203

velocities, there must be certain thicknesses of the crystal, which will make the
difference of their paths equal to half an undulation, or to an odd multiple of
half an undulation. It might be supposed, therefore, that in such cases inter-
ference would occur, so that the crystal should naturally exhibit colors. The
fact is not so; and if we consider the conditions we shall discover without diff-
culty the reasons why it is not. If, in Fig. 52, the two components g a and 7‘ of
one of the circularly polarized rays be supposed to advance or ga uin upon g’ and
r, the distance between g and q’ will diminish until ¢ passes q’, ‘and the distance
between 7 and 7’ will constantly increase. If e¢ represent the amount of advance,
the distance of 7’ from the plane of gr in the figure will be c++4/, and the dis-
tance of g from the same plane will be c only. Now, since g and q’ are equal,
the resultant to which they are equivalent will fall half way between them,
(page 167.) The same is true in regard to the resultant of 7 and 7’. But the
point half way between g and q! will be situated at a distance frora the plane
gr which is the mean of the distances of g and q’; thus—

Distance of Tae Dh fin ee deel
Distance of q/= wf ean ae dt) = dere

In like manner—

Distan i :
Distance of ace 42 fMOm—Ue+ 4) eth
That is to say, the resultants of the components in ec ach plane always coincide
in position. We have next to consider their values. From the statements
above it appears that the distance between r and 7’ is the entire distance of 7”
from the plane gr—that is, —=c+44. And the distance between g and q' is the
difference of the distances of g and q' severally from the same plane gr—that is,
c— i.
Tn the general equation for the resultant of two waves whose molecular move-

ments are in the same plane, (equation [3,]) we must accordingly introduce the
following values of 0:

N

Por g and q/, 9=27(5—2).

For 7 and 7, 6=2z (5+4).

Then putting Pp for the first resultant, and p’ for the second, and remembering
that g— q’—=r=.’, the equations become,

_

ee aN rah eh Choa Wee sary 78 ie Tey LO 2.805 8 sien
O==T 7 err cos2n (eas er —277 sin275—= 2 1—sin2r, :

Whence p?+p?=29?+27?—=con-tant. And the intensity of the light is inva-
riable.

By considering the foregoing values of p? and p”, however, it will be seen
that they are severally variable, though their variations are always compen-
satory. Ifé be any number of half undulations—

P=P+q’ 2+ 2aq' cos: a(5— NS =P+q"?4+2¢q' sinda. — 2¢° (1+sinzc€),

c i
Sin2z —0 and =?

But if ¢ be an odd number of quarter undulations,

Sings—1 or—1; and either p?=—0, or p?—0.

N

Both p? and p”, therefore, pass through a succession of maxima and minima,
the increments of the one corresponding always in value to the simultaneous

204 UNDULATORY THEORY OF LIGHT.

decrements of the other, and each becoming periodically zero. It accordingly
follows that if two circularly polarized rays, whose molecular gyrations are
performed in opposite directions, be thrown together in a nearly common direc-
tion, and observed by means of an analyzer, fringes of interference may be de-
tected in the two principal azimuths, those in one of these azimuths being com-
plementary to those in the other.

Mr. Babinet made this observation, employing Arago’s prism to produce in-
terfering pencils of plane polarized light ; which pencils he polarized circularly
by means of “ quarter-wave lamin ”’ of mica placed in their paths. ‘The gyra-
tions were made of opposite kinds in the two pencils, by placing the two laminz
so that their principal planes should be at right angles to each other. As an
analyzer, he employed a doubly refracting prism. ‘The fringes immediately
appeared; thus furnishing a very interesting experimental corroboration of a
theoretic anticipation.

In the year 1845 Mr. Faraday communicated to the Royal Society of London
a very remarkable discovery which he had made, of the apparent influence of
magnetism upon light. If any homogeneous transparent body be placed under
the influence of a powerful electro-magnet, it will possess the property, while
the magnetism is maintained, of turning the plane of a ray of polarized light
traversing it in the direction of a line joining the magnetic poles, in the same
manner as such a ray is turned by quartz, or by liquids possessing the property
of rotatory polarization. Mr. Faraday was at first disposed to attribute this effect
to a direct action of magnetism on light, but that idea is now abandoned; and
the received opinion on the subject supposes that the molecules of the medium
undergo some modification during the continuance of the magnetic influence,
which assimilates their action upon the ether to that of substances which pos-
sess permanently the power of rotatory polarization. ‘The direction in which the
plane of polarization was turned in these experiments depended on the direction
of the electric currents. When the currents were reversed, the rotation was
reversed also. It is impossible in this place to do more than to allude to this
interesting discovery.

§ X. CHROMATICS OF POLARIZED LIGHT.

We will now proceed to apply the principles we have been considering to the
«xplanation of the colors produced in doubly refracting substances by polarized
light. We have seen that double refraction consists in the generation of two
waves of unequal velocity and of dissimilar form in the doubly refracting body.
We have also seen that the molecular movements in the two waves are at right
angles to each other. In consequence of the inequality of velocity the two rays
into which a doubly refracting body divides a single incident ray may emerge
from a surface opposite and parallel to the surface of incidence in different
phases. If not entirely separated by the deviation of their paths, they may
thus, so far as phase vs concerned, be in condition to interfere. But we have
seen that interference is impossible between waves whose molecular movements
are perpendicular to each other. If, then, by any contrivance, we can turn the
planes of polarization of two rays which, by double refraction, have been made
to differ in their length of path by half an undulation, or by any odd number
of half undulations, so that these planes shall coincide, interference will be pro-
dueed. It is this which is done in the arrangements which have been described,
by which the gorgeous colors first observed by Arago in plates of doubly re-
fracting crystals, are made to appear. In the first place, the lamina must be
doubly refracting, in order that there may be two rays. In the second place,
it must be thin, that the difference of length of path may be small. In the third
place, the original light must be polarized, otherwise there will be two systems
of interferences compensating each other, and obliterating each other’s effects.

CRYSTALLINE PLATES IN POLARIZED LIGHT. 205

In the fourth place, the principal plane of the lamina should, in order to produce
the most complete interference, be at an azimuth of 45° to the plane of original
polarization—the two rays being, in this position of the crystal, exactly equal
to each other. In the fifth place, we must observe the phenomena by means of
an analyzer, which allows only the light polarized in a single plane to come
to the eye, or which, like a doubly refracting prism, separates the emergent
light which is polarized in one plane from that which is polarized in the trans-
verse plane; otherwise in this case again we shall have the blended effeets of
two compensatory interferences. Finally, the principal plane of the analyzer
should, in order to produce the best effect, be at an azimuth of 45° from the
principal plane of the lamina. The necessity of this condition may be readily
deduced from the law of Malus. ‘The annexed figure may illustrate the changes
which take place in the passage of the ray
through the system. If the arrow, P, rep-
resent the direction of an elementary mo-
ter lecular movement of the original polarized
ray, this movement will be resolved in the
lamina into two movements at right angles
to each other, and each inclined 45° to P,
as shown by the arrows R, (the ordinary ray) and R, (the extraordinary.)
Suppose these rays to emerge, without difference of path, from the lamina, and
to be received upon a crystal of Iceland spar whose principal plane coincides
with the direction of P. JThen R, will be resolved into R,, and R,,; and R,
will be resolved into R,» and R... Ry and R,, will conspire, and Ry, and Ry,
will conflict. The first pair, on the supposition we have made, will only be
effective. The second will destroy each other.

But R, is retarded (in the case of a negative crystal) behind R,. Let the
retardation amount to an odd number of half undulations, and the arrangement

of the illustrative arrows will be what is
seen here. In this case the pair in the prin-
cipal plane of the analyzer conflict and are
Ree destroyed ; while the pair in the transverse
R,- Plane conspire. And this represents what
actually occurs, when the thickness of the
7 lamina is such as to produce exactly the

peta amount of retardation here supposed.

But since the undulations of the component rays of white light are unequal
in length, the retardation which will be sufficient to suppress one color, will not
entirely suppress the others. The ray R,o+Reo will not therefore be wholly
extinguished, but will exhibit a color which will be the resultant of the unsup-
pressed tints. Moreover, the retardation which produces perfect coincidence in
the ray R,.+Re. for one color, will not do the same for the rest. There will
therefore be a color in this ray also, in which the tint suppressed in the other
plane will be predominant. It is to be observed, however, that when the plate is
so extremely thin that the retardation suffices only to produce a difference of
path equal to a single half undulation of the mean ray of the spectrum, or less
than this, no color will appear. And the reason will be obvious, if we consider
that, though the undulations of the different colors are unequal, their inequal-
ities as compared with the total length of the mean undulation are not great.
‘The undulations of the middle violet, middle green, and middle red—the extreme
and mean colors of the spectrum—are approximately in the ratio of the-num-
bers 17, 21, and 26. A retardation of half an undulation of the ereen would
therefore be about the fourth part more than a half undulation of the violet;
and a fifth part less than a half undulation of the red. But a retardation of
Jive half undulations of the green would be not far from s7x half undulations
of the violet or four of the red. ‘The violet and the red, therefore, having in »

Vig 53.

206 UNDULATORY THEORY OF LIGHT.

this case lost (approximately) an even number of half undulations, will comport
themselves, on being restored to the original plane of polarization, as if they had
lost nothing at all; while the green, which has lost an odd number, will inter-
fere and be extinguished. ‘The tint observed in this plane will accordingly be
the resultant of red and violet; which, on account of the comparative feebleness of
the violet, will be but a slightly modified red. In the transverse plane, however,
the red and violet. will interfere and be extinguished, while the green compon-
ents will reinforce each other, and produce their characteristic tint.

It will be seen that the planes of polarization of the pairs of rays which pro-
duce the complementary effects we have been speaking of, undergo two succes-
sive movements. ‘The first movement is from the original plane of polarization.
The second movement is, for one pair of rays, similar to this, and for the other,
opposite. ‘The opposite movements restore the pair of rays which they atftect,
back to the original plane of polarization: the similar movements carry the
other pair of rays into the transverse plane.

If there were no difference of path introduced in the passage of the lamina,
or in the case that the ditference of path produced were always an even number
of half undulations, two movements in contrary directions would simply restore
the ray to its original condition, and produce no interference; while two move-
ments in the same direction would extinguish it entirely. But if an odd number
of half undulations has in any case been lost, two successive contrary move-
ments will extinguish the ray, and two scmi/ar ones will restore its original con-
dition. A single half undulation of the mean ray of the spectrum lost, will pro-
duce a total, or almost total, extinction of the light, after two contrary move-
ments; and will produce sensibly white light after two similar movements.
Plates so thin as to produce a difference of path less than this, will fail to ex-
tinguish the light in cither plane; but, as the thickness goes on diminishing,
the original: plane will gain and the transverse plane will lose; until, when the
thickness is zero, the light will be entirely restored in the first, and entirely
lost in the second.

It is common to speak of polarized light which has passed in this manner
through a thin crystalline lamina, as having undergone depolarization in the
lamina: an expression which seems to imply that it is restored to the condition
of common light. his, however, is not true. There is one analogy between
the cases, which consists in the fact that the vibrations of common light, when
resolved into components parallel to two planes passing through the direction
of the ray and normal to each other, are equivalent to those of the two rays
into which the one original polarized ray is divided by the lamina. But the
great dissimilarity of physical condition between the two is evidenced by the
fact that in the one case the analyzer produces colors, while in the other it does
not. ‘There is a particular thickness of the lamina which produces something
more resembling depolarization. It is that at which one ray is retarded behind
the other a single quarter of an undulation. In this case the analyzer finds an
equal amount of light in both planes, and in fact in all planes; so that, so far
as this test is concerned, the light is truly depolarized. But we have already
learned that this amount of dislocation of the rectangular components of molecular
movement in a plane polarized ray—the components being equal—produces
circular polarization. And in fact, the most convenient mode of producing cir-
cularly polarized light is to employ for the purpose what is called a “ quarter-
wave lamina.” Such a lamina will convert a plane polarized ray, incident upon
it in azimuth 45° to its principal section, into a circularly polarized ray.

When the lamina which is the subject of experiment is so thick that the
difference of path between the two rays amounts to many half undulations,
then no color can be totally extinguished in cither plane. For it must be
remembered that each color occupies a considerable space in the spectrum, and
therefore has undulations belonging to it of many different lengths. The dif-

CHROMATICS OF POLARIZED LIGHT—FORMULZ. 207

ferences may be slight, but slight values many times repeated become large
values at last; so that two red rays whose phases are for several undulations
sufficiently unlike to conflict, may, after a larger number, be nearly enough alike
to conspire. If the numbers 21 and 22 represent the lengths of two undulations
of green, after a retardation of eleven times the length of the former, the latter
will have fallen half an undulation behind it. Thus, after a certain amount
of retardation is reached, there will be found undulations of all colors im-
partially distributed through all varieties of phase, and the chromatic phenomena
above eee will cease.

A general expression for all these phenomena
may be found as follows: Let PP’ be the plane
of polarization of the original ray ; QQ’ the princi-
pal plane of the lamina; RI the conjugate plane ;
QO’ the principal plane of the analyzer, which we
will suppose to be a doubly refracting prism or
rhomb of Iceland spar; and EE! its “conjugate
plane. Draw PA, PB, perpendicular to QQ’ and
RN’; BI, BG perpendicular to EE’,O0’; and AD,
AI perpendicalar to 1’, OO’. ‘Then if CP rep-
resent the velocity of molecular movement in the
original ray, CA and CB will represent its equiva-
lent components in the directions RR and Q’Q.
If these components be further decomposed in
the directions OO’ and ELE’, we shall have the original velocity CP represented
by the four elements CG, CH in the principal plane, and CD, CF in the con-
Jugate plane of the analyzer.

tepresent the original velocity CP by V. Put the angle PCQ—a, and the
angle PCO=,. Then the angle OCQ will be a—p. The tri iangles PC_A, PCB
give CA=Vsina; CB=Veosa. Andthe triangles ACD = ACH, and BCF=BOCG,
give CD= sinacos(a—p) ; ; CK=Veosasin(a—s); CG=Vecosacos(a—p} ;

Big. 55:

7) i
CH=Vsinasin(a—g). Mien, to find the resultant of CG, CH, the molecular
velocities of the two rays emergent in the plane OO’—that is, of the emergent
ordinary ray—we recur to the general equation—

A? =a" +a" + 2aa' cos6.

in which we must substitute for a and a’ the values of CG and CH given above;
and for 0 the amount of retardation in phase of one of the rays behind the
other in passing the lamina, which, if 4 represent the actual difference in length

h ene
of path, may be represented by 2 ene. The equation just stated may be con-

veniently transformed by adding 2aa’—2aa’ to the second member, when it will
become—

AV?=@+a?-+ 2aa' —2ad' + 2aa!'cosd.
Or A?=(a+a'?—2aa! oe ae —4aa'sin® 40.
Substituting now the values of a,a’, and 0, we obtain—

Re Ve [ [eosaeos(a—) -+sinasin(a — /) |’— 4sinacosasin(«— /)cos(a—)

Which may be reduced to the following entirely equivalent forms:

Wes ye [ costs + [cos?(2a—?) — costelsint, | : [37]

A?—Y? | cost — [sin?(2a—/) — sin] sints) | , [38.]

208 UNDULATORY THEORY OF LIGHT.

And by pursuing a similar course with the values of the components CD,
OF, of the extraordinary ray, we shall obtain for its resultant intensity the two
values, also equivalent to each other—

Alta Vve ‘ee [sin?(2a—/?) — sin?gsin’ | [39.]
2s pen eouae
A? —V¥ | sire —[cos?(2a—/3) —costajsintss | [40.]

The intensity of the light in either plane is thus expressed in a formula of
two terms, one of which is affected by interference, while the other is not. It
is from the second that the colorific effects proeeed—directly, when this term is
positive relatively to the first, and indirectly when it is relatively negative.
This term may therefore be called the chromatic term, and the other the achro-
matic.

In considering these equations we observe, first, that if we add either value
of A’ to either value of A’, the chromatic term disappears. The colors are
therefore complementary; and if blended, the resultant is white.

Secondly, since A?+A”—V?(cos?@+sin??)—V?, the sum of the two intensi-
ties is equal to the intensity of the original ray; as it ought to be on the princi-
ple of the preservation of living forces.

, : ; ee ’
Thirdly, the chromatic effects being dependent on the factor sin’s for their

character, will be dependent not only upon this factor, but also on the coefficient,
sin?( 2a—?)—sin’p, or cos?(2a—C)—cos*}, for their guantity. Their greatest values
will hence occur when this coefficient is maximum. There being two variables,
a. and 8, if we make the first constant, we shall find maxima when cos2(a—?)=0,
or cos2(?—a)=0. This gives a series of values for 2(a—) or 2(6—a’‘,
which are 90° and its odd multiples. It is sufficient to consider the first, which
gives a—P=45°, or 3—a—45°; from which e—6+45°, or a=S—45°. For
the higher values we need only replace 45° by the numbers 135°, 225°, 315°,
&c., successively. These values substituted in the coefficient all give the same
result; hence all the maxima dependent on ? alone are equal; and it is obvious
that they are independent of a, since a is not a function of 8. If we find, then,
the maximum with reference to a, and substitute in the resulting expression,
instead of 2, its value =a-45°, as obtained above, we shall have the maximum
of the maxima, or the azimuths of QQ’ and OO’, in which the chromatic effects
are the most brilliant possible. The solution gives sin(4o—23)—0. Hence
4a—28=0, or 180°, or 360°, &c. Contenting ourselves with the first value,
and substituting for 8, we have 4a—2a490°=0, or a=F45°. Andas B=a+ 45°.
we conclude that the arrangement in which the colors will be most brilliant
is that in which the principal plane of the lamina is inclined 45° to the plane of
polarization of the incident light, and in which the principal plane of the
analyzer is in azimuth 0° or 90°—theoretic conclusions already anticipated
by experiment.
Fourth, attending to the first of the formule for A? and A” we see that the
chromatic term in each is symbolically positive. If the term, therefore, is essen-
tially positive in itself, the color of the ray is the color which the interference
expressed by that term would produce, diluted with such an amount of white
light as is expressed by the achromatic term. When the chromatic term in the
same formulz becomes essentially negative, the color will be that which is left by
subtracting its own color from the amount of white in the achromatic term.
‘That the subtraction will be possible—that is to say, that, when the chromatic
term is negative, the achromatic term will always be the greater—will be evident
on inspection. For examining the coefficient of the chromatic term within the
bracket, it will be seen to consist of a positive and negative element, which elements,

CHROMATICS—DISUCUSSION OF THE FORMULA. 209

being squares, have their essential the same as their written signs; but the
negative element of this coeflicient is the same as the positive achromatic term.
Hence the entire coefficient can never be greater than the achromatic term; and
can only be equal to it in the single case when cosine or sine (2a—@)—=0. But

h cel
the chromatic term has another factor, sin’n, which is always less than unity,

except when / is an integral odd number of half undulations. This, therefore,
usually still further reduces the value; so that neither of the expressions for
intensity can ever become negative.

Fifth, if 8 remain constant, the value of the chromatic term will vary with a,
and may even become zero when c=3. The force of the color will therefore
undergo corresponding variations; and all color will disappear in the case just
mentioned. ‘The same also will be true when a=$+490°, B4-180°, &c., &e.
But though, in these positions of the lamina white light only is seen, the eolee
reappears for values of a intermediate between 2 and 84+90°, 84+90° and
B+180°, &c.; and this color is the same as before, since the sign of the chro-

matic term does not change. When a is constant and ? varies, the color in like
manner rises and descends in brillianey, having a minimum —0, at the values
Ba, B=a490° and b=a+4180°, &e. Butas, in passing each of these successive
values, the coefficient of the chromatic term, as is evident on inspection, changes
its essential sign from positive to negative, or the contrary, the tints observed in
the successive quadrants will be complementary to each other.

Sixth, when a=0°, 90°, 180°, &c., the chromatic term disappears for every
value of 3. In this case the light remains white throughout the entire revolu-
tion of the analyzer, and one or the other of the achromatic terms disappears,
for the azimuths 8—0°, P—99°, &c.

Seventh, if we suppose the lamina and the analyzer both to remain stationary
while the polarizer revolves, we shall see that the chromatic term changes its
sign in the course of every quarter revolution. For example, since the change
of plane of original polarization affects the azimuths of the lamina and of the
analyzer equally, if we suppose a revolution of 90° in the negative direction,
the coefficient cos?(2a—)—cos’?? becomes cos*(24+180°—90°—/)—cos*\ 90°
+/2)=cos?(90°+2a—/)—cos?(99°+/3)—=sin?(2a—/)—sin’?. But, by reference
to the two equivalent values of A’, [37.|[38,] we see that cos*(2a—)—cos*é—
—(sin?(2a—j7)—-sin?7.) Hence, in the rotation of the plane of polarization
through an are of 90°, the coefficient of the chromatic term passes from positive
to negative or the contrary. If we suppose a revolution of 180° still in the
negative direction, we shall find the sign once more the same as in the original
po ee Thus, cos?(2a—/)—cos*? becomes cos?(2a+360°—180°—/)—
cos’(180°+2)==cos?(180°+2a—)—cos?(180°+ 8)=-cos*(2a—f)—cos’3. If we
suppose the rotation in the opposite direction, the alternations are similar.

It is, hence, manifest that unless the light employed in these experiments be
originally polarized, no chromatic phenomena will make their appearance. For
unpolarized light being made up of successive undulations impartially distributed
through all azimuths, those which are embraced within any one quadrant will
neutralize the effects of those within the adjacent one, the complementary colors
produced by each similarly situated pair succeeding each other with such rapidity
as to blend their effects upon the retina.

i : lest Ti
Kighth, if we consider the factor sin’xs we shall see that, when A==$,,

2A, &c., the value of this factor is unity, which is its greatest possible value.
‘The chromatic effect-is, therefore, greatest when the retardation of one AY upon
the other is an odd number of half undulations. If, in this case, ?—=2a, then
A’?=Y", and A?—0. If P=2a+90°, A2—0, and A”?—V*. Supposing, there-

14s

210 UNDULATORY THEORY OF LIGHT.

fore, the light homogeneous, the apparent planes of polarization of the emergent
rays will be in azimuths 2a and 24+90°.

h
Ninth, if A=A, 2/, 32, &c., sin’ = 0; and the equations become simplified

to the forms
A’?—V"cosf; and A?—V’?sin’/,
which are a reproduction of the law of Malus. 'The interposition of the lamina
produces, therefore, no apparent change in the plane of original polarization.
Tenth, if h==4/, 3A, 2, &c.—that is to say, an odd number of quarter .undula-

: any ’ s
tions—sin?x- becomes sin?45°—4. If, then, a—45°, the equations become—
Fi 2 7

A?—V{ cos*8+4(sin®@—cos*/) |==3 V?(cos*3+sin?7)—3 V”.
A®—V"*[sin?#+3(cos?3—sin’/) |= V(sin?8+ cos"? —=3V*.

This result, being independent of the value of f, indicates an apparent depo-
larization of the light. But in fact, it is the case of circular polarization, which
we have already considered. It will be seen that it is necessary to the produc-
tion of the effect that a should be 45°, in order that the two normally polarized
rays may be equal to each other. In any other azimuth of the lamina, the
polarization will be elliptical.

If a lamina of erystal cut at right angles to the axis be employed, then in
the direction of the central incident light the two rays are of equal velocity,

h e : 2 : ’
and the factor aa No chromatic effects will therefore be perceived in the

centre. But the rays which come to the eye converging from points not central,
will differ in velocity, the difference increasing with the obliquity. As every
plane which passes through the axis is a principal plane, there will be an infinite
number of principal planes intersecting each other in the line which forms the
path of the central ray, the projections of which upon the surface of the lamina
will form so many radii diverging from a centre. And as all planes which are
parallel to the axis, however placed, are principal planes also, it is obvious
that the planes normal to these radiating principal planes will form cylindrical
principal sections having a common axis. The plane ef polarization of the
incident light can only coincide with one of the radiating principal planes. For
that plane, the value of @ in our formule will be 0°. For the principal plane
at right angles to that, the value of @ will be 90°. But we have seen that when
a—0° or 90°, the value of the chromatic term is 0. Hence there will be two
planes in which no color will appear for any position of the analyzer—that is,
for any value of #. But the brightness of the light seen in those planes will
undergo variations of intensity, as # varies, according to the law of Malus.

For every plane except the two which have just been mentioned, the chromatic
term will have a value—very slight in the neighborhood of those planes, and
maximum at 45°. Very near to the centre, converging rays will have but a
slight obliquity to the axis; and as a difference in length of path of one-quarter
of an undulation or less fails to produce color in white light, there will be a
central area which will be alternately white and black as the analyzer turns.
rom this area will proceed at right angles the arms of a cross, alternately
dark and bright, which, from the faintness of the color in the neighborhood of
azimuths 0° and 90°, will have a very sensible breadth.

At that degree of convergency which makes the amount of retardation for
the most refrangible rays $A, will appear the first decided chromatic effect.
And as, in a plate of uniform thickness, this convergency must be the same on
every side, the color will take the form of a ring. This ring will be bright if
the analyzer is crossed upon the polarizer; in the opposite position, dark. In
order to observe the phenomena to the greatest advantage, it is best to employ
homogeneous light. Then at greater convergencies, corresponding to retarda-

RINGS SEEN IN CIRCULARLY POLARIZED LIGHT. 211

tions, or values of A, equal to 32, 3A, &c., will be seen, with the crossed analyzer,
other bright rings; while at the intermediate convergencies, corresponding to
values of h=A, 2A, 3A, &c., will be seen dividing rings, intensely dark. When
white light is\used, the dark rings will be mainly occupied by the smaller rings
of the colors whose undulations are shorter than the mean, or the larger rings
of those which are longer. Since the retardation depends directly upon the
convergency, and the place of a ring of any color depends on the equality of
the retardation with the length of a half undulation of that color, it will be
evident without further demonstration, that the longer the undulation the larger
the ring, and wice versa.

Rotating the erystalline plate in azimuth will produce no change in the phe-
nomena. Tor in all positions of the plate there will always be one principal
plane in azimuth 0°, and another in azimuth 90°.

Rotating the analyzer will cause the rings to pass by progressive changes
into the complementary tints. In this rotation ? becomes ==a and >a succes-
sively for every one of the radiating principal planes which it passes, up to
f—90°. The sign of the chromatic term changes, therefore, in every such case.
And, as the sign changes also for S=a+90°, 6=a+180°, or @=a+270°, the color
in all the quadrants will undergo similar changes simultaneously. ‘Thus, in an
entire revolution of the analyzer, the colors will be four times successively
reversed ; and for every position in which g—45° or any of its odd multiples
they will disappear.

The remarkable dislocation of the rings seen in erystals cut across the axis,
when examined in circularly polarized light, has been mentioned. By applying
the principles we have been considering we shall be able now to account for this
singular effect. Suppose the crystal under examination to be a positive one, in
which the ordinary ray has a higher velocity than the extraordinary. When a
circularly polarized ray falls upon such a crystal, its component undulations,
which, as we have seen, are at right angles to each other, with nodes dislocated
by a quarter of aa undulation, will advance with unequal velocities, and the
amount of their nodal discrepancy will be changed. This would not disturb
the symmetry of the rings, if the change were similar in all the quadrants. By
attending to the following analysis, we shall see that such is not the case.

Let RR’ represent the direction of progress of a circularly polarized wave,
of which the component invlecular movements are represented by PP’ and QQ”.
The positions of these arrows are those in which the molecular movements of
their respective undulations are assumed to be at their maximum of velocity,
and the distance between them, upon the line RR’, is to be taken as represent-
ing a quarter of an undulation. If we consider the effect of this composition of
forces upon a molecule in the plane of movement of QQ’, we shall perceive that

919 UNDULATORY THEORY OF LIGHT.

PP’ will there be about commencing the return movement, in the direction
denoted by P”, while QQ’ will be in the height of its activity.

The actual position of the molecule in the orbit described on QQ’ as a dia-
meter will in fact be at M; but QQ’ and P’’ may be taken as representing the
directions of motion at the instant supposed. Let ACBD be a plate of the
erystal cut across the axis, and let the analyzer (not represented) have the plane
of its free molecular movement parallel to AB. Draw CD at right angles to
AB, dividing the crystal into four quadrants.

As all the molecules in the wave front are actuated by similar movements, it
will be sufficient to consider one of them in each quadrant. Let their several
component forces be represented by the arrows marked p q, each pair having
the same relations to each other as PP’ QQ’. It will be possible, in every
quadrant, to draw a radius parallel to p org. Let these radii be drawn. Now,
the radii being principal sections of the crystal, that component in each case
whose direction of movement coincides with the radius, will (if at all inclined to
the axis) be an extraordinary ray, and will be retarded behind the other compo-
nent. An inspection of the figure will show that this will happen for p in the
first and third quadrants, and for g in the second and fourth. Let the inclination
of the rays to the axis be such as to cause a retardation of the extraordinary ray
of one quarter of an undulation behind the ordinary. Then, by comparing the
positions of the arrows which represent the relations of the components after
emergence, it will be seen that the effect has been to bring the planes of maxi-
mum molecular movement into coincidence in the second and fourth quadrant,
and to increase the distance between them to half an undulation in the first and
third.

But these changes are just what is required to obliterate the nodal dislo-
cations in both cases, so that the waves will emerge plane. The resultant
molecular movements in the second and fourth quadrants will be obviously
vertical and parallel to AB. At the inclination or distance from the centre,
therefore, which produces this amount of retardation, will be seen in these
quadrants the first bright ring. Had the incident light been plane-polarized,
however, the first ring would not have appeared until after a retardation of a
half instead of a quarter undulation had taken place; it would have conse-
quently required a greater inclination of the incident ray, and its apparent
distance from the centre would have been increased. In the first and third
quadrants, the resultant molecular movement may be inferred by referring the
two components p and g toa common plane. If qg be referred to the plane of
p, for example, then, as the distance between them in the figure is half an un-
dulation, the arrow g must be reversed, and the resultant movement will be
horizontal. The analyzer will suppress this movement; or, in other words, at
this distance in the first and third quadrants will appear a dark ring. In these
quadrants there will not appear a bright ring until the retardation is increased
half an undulation more; that is to say, to the total amount of three quarters
of an undulation. Plane polarized light would have required a total retardation
of only a half undulation to exhibit this ring. In the first and third quadrants,
therefore, the bright rings are removed outward, and in the second and fourth
they are removed inward, from the places they are seen to oceupy in plane-
polarized light, for a distance corresponding to a difference of a quarter of an.
undulation. |

From what has been said, it will be easy to understand why two crystalline
laminze, of equal thickness, and cut from a crystal parallel to its axis, or equally
inelined to the axis, when crossed upon each other, neutralize each other’s
effects. Tor the original polarized ray is, by the first lamina, divided into two
which we have represented by R,, R,. In the supposed relative position of the
two laminz the ray R, passes without double retraction in the principal plane
ot the second crystal, and the ray R, in the conjugate plane. After emergence,

RINGS IN CRYSTALS OF TWO AXES. 213

and before analysis, therefore, the two rays may be represented by R,, and
Reo, Which symbols show that each has been equally modified in its passage
through the system, and hence, that they reach the analyzer without any differ-
ence of path. In the foregoing formule, accordingly, A==0 for this case, and
the chromatic term disappears.

We also obtain an explanation of the effects produced by nclining the lamina
to the incident light. In general, the increased thickness of the erystal which
the rays will have to traverse at an oblique. incidence, will have the effect to
increase the value of /, and the colors will descend, or take the tints belonging
to thicker plates. But the new direction of the rays within the crystal may be
one in which their difference of velocity is greater or less than that which
belongs to the direction of perpendicular incidence. In this case the tints will
descend more rapidly by inclining in one direction than they do when the in-
clination is opposite; or they may possibly remain stationary, or rise on one
side and descend on the other. We suppose here as before that the analyzer is
crossed upon the polarizer

Crystals of two axes, cut at right angles to either axis, will exhibit elliptical
rings, the variations of velocity of the two rays being subject to different laws
in the principal plane which contains the two axes, and in two other principal
planes co-ordinate to that. When the axes are not largely inclined to each other,
a lamina of the crystal taken perpendicularly to the line bisecting the angle
between them will exhibit both systems at once. In these crystals neither ray
obeys, in general, the law of Snellius. But there are three planes—those just
mentioned—in which one of the rays obeys this law. ‘These three planes are,
in the first place, that which passes through both axes; and, secondly, both the
planes normal to the first, which bisect the angles between the axes. The terms
“ordinary ray’ and “ extraordinary ray,” in the sense in which those words
have been used, in speaking of crystals of one axis, are inapplicable in the
present case.

The following equation, deduced by I’resnel from the general theory of double
refraction, expresses the relation between the velocities of two rays traversing
the crystal in the same direction, but possessing the differing polarizatious
produced by its double refraction :

pov pola Aap. sagt ini, wey
2 (ae) singsing’. [41.]

In this formula, v and 2’ are the two variable velocities; @ and ¢ are the Sne/-
lian velocities (constant) in the two principal planes co-ordinate to that which
contains the axes; and ¢ and ¢’ are the angles made by the common direction
of the two rays with the axes themselves.

It may be remarked that the rays whose velocities are here denoted by v and
v', cannot be the two rays which proceed from one incident ray, since these two
rays do zot pursue the same course within the crystal. This consideration is
not important, when the divergence of the rays produced by double refraction
is small, (which is the case with most crystals of two axes, and with ad/ for rays
in the vicinity of the axes themselves ;) and therefore we may employ this law
for the purpose of determining the forms of the colored rings, in plates cut
so as to make it possible to observe both axes at once. Putting vv'=ae and

v-+v'—=2 Vac, suppositions which are sensibly true near the axes, the formula
gives—
shining vy? (cay abhi: sya sere en ly.)
——)' —= ——— { —. ~— } sinvsing’ = ——__=— DS very nearly.
v4 \ &e sing Bind tae gsing’,, (very ¥
As we propose to confine the inquiry to the immediate vicinity of the axes,
where ¢ and ¢/ are small, we may take the angles themselves, or their chords,

214 UNDULATORY THEORY OF LIGHT.

instead of their sines. Let these chords be r and 7’. Then the equation be-

comes— Va
2

r= (vv), [42.]
which, if :—v’ be made constant, is the equation of
alemniscaie. 'The annexed figure represents a /em-
niscate, or curve whose distinguishing property is
that the products of every pair of radi vectores,
drawn from two polar points, and intersecting in the
curve, are equal to each other, and to a constant
quantity. If PQ, the distance between the poles,
Kie 87 be bisected at A. and PA made = gq, then the con-
é stant value of PRx QR, divided by gq, is called the
parameter, and may be represented by p. Put PR=z, QR=7’, AN=za, and

RN=y. The construction gives, immediately—

P=(q+e)4y; P=(g—2)+y": whence
PrP=((q-+a) +9) ((q—2) +97) =P"e-
Or P= (PietyyAgr=p¢_. [43.]

In the ease in hand, the parameter is the quotient. found by dividing the
second member of the equation for the velocities, in its last form, by g. ‘The
value of g itself may be directly measured, if the
chromatic image be thrown upon a screen, as was
done by Sir John Herschel in his study of the forms
of these curves; or it may be assumed at pleasure,
from a knowledge of the angle between the axes.
Thus, if ABUD be the lamina, and aa’, b6' the axes,
then, to the eye at E the poles are a and & in diree-
tions parallel to aa’ and 60’; and half their distance
is the value of g. The rings, however, may be re-
ferred to any distance, as EP; and the poles will then
be at Qand R. The distance EP and the angle REQ are all that is necessary
to determine g, which is now PQ. It must be observed, however, that for a
projection on this scale, the value of the constant, or second member of the
equation above, must be increased in the ratio of the square of the distance of
QR to that of AB from the eye.

When the direction in which the rays reach the eye is such that the differ-
ence of path of the two rays is half an undulation, there will be seen, in homo-
geneous light—the analyzer being crossed upon the polarizer—the first bright
rine. When the difference becomes an entire undulation, the first dark ring
will appear. The parameter of the lemniscate changes with every new ring.
For the bright rings, the parameters will evidently form an arithmetical series,
corresponding to the odd numbers 1, 3, 5, 7, &c. Por the dark rings there will
be a similar series of values, proportional to the even numbers.

The lemniscates are not perfect, (though some of them are nearly so,) because
we have admitted some small errors into our assumption. The inner curves
also will, in many cases, form ellipses around a single pole. It is obvious that
this must be the case when the constant is less than g*. For ¢ is the smallest
value that the product of the radii vectores can have; and when the parameter
is not equal to g, there can be no lemniscate. i

When the analyzer is crossed upon the polarizer, in observing these curves,
if the plane of the axes is in the plane of polarization of the incident light,
there will be seen a black cross intersecting the system symmetrically; the
principal bar of which will coincide with the plane of the axes. The transverse
bar will pass at right angles to this, half way between the poles. In these two

Fig. 58.

DOUBLE REFRACTION. 215

planes there is (in the position of the crystal supposed) no double refraction of
the incident polarized ray. The light is therefore transmitted without interrup-
tion, and being cut off by the analyzer, shows the dark cross. By rotating the
analyzer 90°, the cross becomes bright, as with crystals of one axis. But when
the crystal itself is turned in azimuth, while the analyzer remains in one of the
principal azimuths, the arms of the cross break at the centre, two of them on
each side forming together a curve. At 45°, the two curves present the appear-
ance of opposite hyperbolas.

To follow these changes analytically would require a larger acquaintance
with the physical theory of double refraction than is furnished in what precedes.
We will therefore, next in order, turn our attention to that subject.

§ XI. DOUBLE REFRACTION.

We have seen that the double refraction of light is always attended with
polarization. It is proposed now to attempt a physical explanation of this
phenomenon.

Refraction, in general, considered as a’ bending of the ray, is owing to a
change in the velocity of the wave as it enters the refracting medium. When
the refraction is double—in other words, when a single wave is divided by re-
fraction into two waves—the velocities of the two waves must be unequal. It
is presumed that this difference of velocities is owing to a difference of elasticity
of the ether within the medium. But, inasmuch as the two rays often follow
the same track, each with its own determinate velocity, while they remain quite
distinct from each other, it is evident that their velocities cannot be determined
by the elasticity of the ether éz the direction of their progress. It becomes
therefore a necessity to assume that their molecular movements are transverse
to the ray, and in the surface of the wave itself. The fact of double refraction
is thus an incontrovertible proof of the truth of the doctrine of transverse vibra-
tions, independently of the many evidences of the same truth derived from po-
larization and the phenomena of interference.

But inasmuch as, in a medium in which the elasticity of the ether varies ac-
cording to a certain law, the elasticity will usually be different in each of the
indefinite number of planes which may pass through a given ray, it follows that
if the ray pursue a determinate course with a constant velocity, its transverse
vibrations must be confined to some determinate plane. Double refraction in-
volves, therefore, as an indispensable condition, polarization; and, as a general
rule, plane polarization would secm to be the necessity.

Experiment proves that these theoretic inferences are correct; and also that
the planes of polarization of the two rays which originate from a single incident
ray, in a doubly refracting body, are at right angles to each other. ‘Two ques-
tions present themselves, therefore, for solution: First, how is the direction of
molecular movement in a polarized ray related to the plane of polarization? and
secondly, what cause determines this movement in the doubly refracting body,
to these particular directions ?

In regard to the first question, we may arrive at a conclusion, by considering
the case of a erystal of one optic axis, like Iceland spar. If we suppose such
a erystal to be ground to a perfect sphere and polished, a ray ineident perpen-
dicularly upon any part of its surface will coincide in direction with the radius
of the sphere. Such a ray falling upon a sphere of homogeneous glass would
pass undivided through the centre. But with the sphere of crystal which we
have supposed, there is but one diameter in which this will happen. ‘This is the
diameter coincident with the optic axis; and in this direction there is no double
refraction. If the incident ray is common or unpolarized light, (a supposition
which is to be understood in all that follows,) the emergent ray will be unpo-
larized also. And, as the molecular movements of common light are in all

216 UNDULATORY THEORY OF LIGHT.

azimuths around the ray, it is evident that the elasticity of the ether in the
crystal is the same in all directions at right angles to the optic axis. The mo-
ment, however, that we depart from the pole of the sphere—maintaining still a
perpendicular incidence upon its surface—a second ray makes its appearance.

The light is now equally divided. A part, which we call the ordinary ray, still
follows the radius and passes through the centre of the sphere. The other
portion is bent at the surface, and crosses the diameter in which we found no
double refraction, above the centre or between it and our first supposed point of
incidence; that is, the point which we have called the pole. The deviation will
be slight at first, and will go on for a time increasing, as we descend in /atitude;
but will afterwards diminish till we reach the equator, when it will become
nothing. But though the deviation diminishes, the double refraction increases ;
that is to say, the difference of velocity between the two rays becomes greater
and greater as we approach the equator, and in that plane attains its maximum.

Both rays now pass through the centre; but one is so far behind the other that
two images may be seen of any object ‘beyond, at different apparent distances
from the eye. If the incidence be xot perpendicular, the ray which has always
passed through the centre undergoes refraction according to the simple law of
Snellius, in all planes and in all azimuths; but this is not at all true of the other.
The inference is that the velocity of the first of these rays is always deter-
mined by the same elastic force; which must be that foree which we have seen
to be at right angles to the axis, or parallel to the equator of our supposed
sphere.

And here, in order to avoid error or confusion, let it be observed that the
line which we have called the axis of this sphere is not ¢he optic axis of the
erystal, but only one of the optic axes. All lines parallel to this are equally
optic axes. In other words, the name optic axis is the name, not of a dine, but
of a direction.

Now if we once more follow, in mind, our ray at perpendicular incidenee,
from the pole of the sphere to the equator, we shall see that there is no difficulty
in imagining its molecular movements to be constantly parallel to the equator, pro-
vided we suppose them perpendicular to that meridian plane (principal seetion)
which passes through the ray and the axis of the sphere. The constant velocity
of the ordinary ray is thus accounted for without difficulty.

The velocity of the extraordinary ray being variable, its molecular movements
must encounter a different elasticity in different directions of its progress.
Moreover, as its plane of polarization is at right angles to that of the ordinary ray,
its molecular movements should be so likewise. We have only to suppose these
movements to take place zm the meridian, or principal section, plane, and we
shall see that they will turn with the ray itself, as we pass from the pole to the
equator: so that, while, in the first position, they are parallel to the equator
like those of the ordinary ray, they are inclined to it at increasing angles
as we descend in latitude, and become perpendicular to it in latitude zero;
that is, when the ray is in the plane of the equator itself. Now this would
make no difference in the velocity, provided the ether were equally elastic
in all directions. As the velocity 7s variable, in point of fact, the conclusion
raust be that the elasticity is variable also. In the direction of the axis we
must assume it to be greatest, and in intermediate directions to possess an inter-
mediate force.

Now the plane of polarization of the ordinary ray (experimentally ascertained)
is the principal section of the crystal. And as we have been compelled to con-
clude that the molecular movements of this ray take place at right angles to the
principal section, it follows that, in plane polarized light, the vibrations are at

SURFACE OF ELASTICITY. ore

right angles to the plane of polarization. This settles the first of the questions
proposed above. ‘The second is less simple.

If a polarized ray, whose molecular movements are
in the direction OP, in the annexed figure, fall upon
a lamina of doubly refracting crystal, whose principal
section is MM’, it undergoes double refraction in every
ease except that in which OP coincides with MM’
or NN’, the conjugate plane. The effect is the same,
in seeming, as if the Jamina allowed no free passage
for movement, except in these directions. The im-
aginary structure presented in the figure is in ae-
cordance with this idea. The undulations of which
OP is an element, encountering such a structure,
would be necessarily resolved into two movemeute,
taking the directions of the open passages; and
according to the laws of the resolution of forces, we should have OP? =OQ?+40R?,
Or putting I for the total intensity of the light, and a for the angle between OP
and MM’,—

I= Icos*a+ Isin*a,

which is the law of Malus.

This illustration is given merely to facilitate the conception of the constant
determination of the ethereal vibrations in crystalline bodies to fixed directions.
The cause must be one more general than such a mechanical structure could pos-
sibly be. ‘The theory of Fresnel, embracing all the cases of double refraction,
is founded on the assumption that the elasticity of the ether may be different
in the directions of three rectangular axes; and among the conclusions mathe-
matically deducible from this assumption, is the proposition that, in a medium
so constituted, the molecular movements of an incident ray will be unstable
except in two determinate azimuths at right angles to each other. If they are
not in those azimuths, or one of them, on entering the medium, they will be
instantly ¢wrned into them; and thus the ray will be polarized in planes having
different directions in the crystal.

If we take a crystal of two axes, and form from it prisms, of one of which
the edges shall be perpendicular to the plane containing the axes, while the
others have their edges respectively parallel to the lines which bisect the angles
between the axes, we shall find that, in the planes of refraction of these prisms,
one of the rays follows the law of Snellius; but that the indexes of refraction
for these are different. ‘These rays thus obeying the ordinary law are moreover
polarized em their several planes of refraction. ‘Their molecular movements are
therefore perpendicular to those planes, or parallel to the edges of the prisms,
that is to say, parallel (by construction) to three determinate fixed lines in the
erystal, each at right angles to the other two. ‘These velocities, then, determine
the elasticities in the direction of three rectangular axes. Irom these as constants,
Vresnel derived an equation expressing the elastic force in all intermediate
directions. The three velocities are distinguished by the Ietters a, & and ¢, in
the order of their magnitude—that denoted by @ being greatest. And elasticities
being as the squares of the velocities which they generate, the three elasticities
are a”, b*, and c?. Now if any line be taken which makes with the directions
ot the elasticities a’, 0’, c?, angles represented by A, B and C, and if R denote
the velocity which the elasticity in the direction of that line is capable of gen-
erating, then we shall have the equation—

R?=a?cos?A+07?cos?B-+-c?cos?C. [44.]

Giving A, B, and C all possible values, Rt will have all possible directions ;
and, considered as a radius vector, its extremity will describe a surface the

218 UNDULATORY THEORY OF LIGHT.

squares of whose radii will be equal to the elasticities in their directions. This
surface, therefore, Fresnel denominated the surface of elasticity.*

The surface, as might be inferred from the principle of its construction, is an
ellipsoid, of three unequal axes.

Now, it is a point important-to be clearly conceived, that when, in a medium
of variable elasticity, the equilibrium of forces is disturbed by a displacement
of its molecules in a given direction, the resultant of elastic resistances excited
is not generally in the line of the displacement. Were the displacement to take
the direction of one of the axes of the surface of elasticity, the resistance would
be directly opposed to the disturbance. But suppose it to be in the direction
of some oblique radius; and, to simplify the matter, suppose this radius to be
in a plane passing through two of the axes. Let then, in Fig. 60, ADBE be
the section, passing through AB and DE, the axes of greatest and least elas-
i ticity. Let, a molecular disturbance, which we will call
7, take place in the direction CF; and, for facility of
conception, let us take the line FC itself to represent
the resistance it encounters 7z this direction. AC is a,
and DC isc. Now, the displacement 7, if it took place
wholly in the direction of a, would develop a resistance
proportional to 7a’, or equal to fra”, f being a constant.
And if it took place wholly in the direction of ¢, it
would develop a different resistance— frc?. But the

Fie. 60, amount of displacement in the direction of @ is only

reosA. And that in the direction of ¢ is only reosC.

Also, as A=ACF in this case, and C=90°—ACF, we have rcosC=rsinA.

Hence the resistances developed are fra®cosA, and fre’sinA. Now, the first

of these expressions being the horizontal component of the resistance (as the

ficure is drawn) and the second, the vertical, the second divided by the first
will give the tangent of the inclination to a, which inclination we will call A’.

Redes 2
a resin Ue dicks “an Al . [45.]
JrvcosA a
which is less than tanA —or the resultant is less inclined to @ than FC.

A graphic method of determining the resultant, both in magnitude and di-
rection, is suggested by this formula. TanA/ is a fourth proportional to a’, c’,
and tanA. Calling KC radius (for present purposes) FK=tanA. Draw FR
perpendicular to DE, and join RB. Join AL, bisect it in M, and draw MN
perpendicular to AE, With N as a centre, describe the are EP. Then CE?=
C=AC.OP. And CB=@=AC.CB. Or, @::er: CB: OP. .Draw; there=
fore, PY parallel to BR, and QO parallel to AB. Draw FG perpendicular to
FC, and the radius CO, through O, to meet it inG. OG is the resultant, and
GCA=A’.

The resultant force consists, then, of two components—one, equal and oppo-
site to CF, and the other FG at right angles to it. This latter force deflects
the motion of the molecule in FC, and turns it toward the shorter or longer axis,
according as the movement is one of condensation or of rarefaction. And there
ean be no stability of oscillation in this place, in any line which is not parallel

Then

‘

* This polar equation may be referred to rectangular co-ordinates, by putting x, y, and z for
the co-ordinates parallel to a, b, and c, respectively, and substituting the following values:

Qo tela oadlee® iy Maio Og the ot
Rex? y?-++-2*. CosA=yi cosB= 53 cosC= 5.

Whence Rt=a?x?-+-b?y?--c?2z2.
Or, (22-by?+-22)P=a2x?-+L 22-0222,
which is an equation of the fourth degree,

RESULTANT OF ELASTIC RESISTANCES. 219

toaorc. In either of those directions the displacement develops no deflecting
force; since, in the former, cosA=1 and sinA disappears; and in the latter
smA=1 and cosA disappears.

The arrows illustrate the relations and mutual action of these forces, and the
corresponding movements of the molecules. During compression the disturbing
force is CF, and the movement from C toward F. The opposing component
of the resistance is C’F’, and the deflecting component GF. While CE pre-
dominates over C’T", the point of the arrow CFf—that is, the direction of the

-molecular movement—will be turned nearer the direction CD. But when C’F
predominates over CF, as in the return vibration, ©’/F represents the move-
ment, and the deflecting force turns the point of the arrow C’F nearer the
direction AC.

The value of the resultant may be determined by means of those just given
for its components, from the right angled triangle CGH. For this gives us,
(putting p for the resultant, )

p= f*rra'cos’ A+ f2r*ctsinZ A ;
or p=+/r V a'cos?A+c'sin2A-
The equation of the surface of elasticity also gives us, for the value of the
radial resistance (denoted by p’)
P=? fr freco? A+ frb-corB-+ frecos’C.
Or, as cosC==sinA, and cosB—cos90°—0,
p'=fr(@cos?A+c?sin? A).
Hence, if represent the angle GCI’, we shall have
p! aco’ A-+e’sin2A a IR?

Cosw—=—— - ee 46.
e = V @eosA+cisin2A V aicos?A-+cisin2A [46.]

c ' This simple ease has been
examined in detail, in order to
facilitate the conception of the
more general one, which will
now be attended to. Let a
molecular displacement, 7, occur
in any direction whatever. Let
CF, Fig. 61, be the direction of
displacement, and let it be as-
sumed as the representative of
the force developed in that di-
rection. As in the former
_ease, if this foree be resolved
into three component forces in
the directions of the several
axes, the resistances developed

will be fra’cosA, frb?cosB,

A
: SrecosC.
|? According to the laws of the
Fic. 61 composition of forces, these three
g. 61.

components are in the relation
of the three dimensions of a parallelopipedon, of which the resultant is the
diagonal. Let CNN/GH, &c., be this parallelopipedon. CG is the resultant
expressing the total resistance in both quantity and direction. But R®f;, by
the equation of the surface, expresses the total resistance in the direction of the

220 UNDULATORY THEORY OF LIGHT.

radius; and if, to facilitate conception and comparison, we conceive it to be
the diagonal of another parallelopipedon, CMM/I'K, &c., the three dimensions
of this solid will be R®freosA, R*freosB, and R? frcosC. For the sake of
symmetry, we will employ for a moment these components, instead of R? fr
itself. We will denote, also, as before, the two resultants by p and p’ and the
angle, GCF, between them, by ». Then,

C Pi suadG V Ricos’?A+R'cos’?B+ Rcos?C hi. R?
So ——— i : .

pP Jr V aco A+6*c0s?B+c'cos?O V atcos*A+b'cos?B+c'cos?’C, .
a’cos’*A+67cos°B+c?cos*C

V a'cos*A+6'%c0s?B+c8cos?C

Or, coso=-+

[47.]

Now the wave front-in which 7, having the direction CF, is one of the move-
ments, cuts the surface of elasticity in an ellipse, which may be represented by
ADBE. The line CG will not usually lie in the plane of this ellipse. If the
resultant, p, be decomposed into two forces, one of them equal and opposite to
p’, or CF, and the other GE, perpendicular to CI, this last tends to turn the
movement in CIF out of that line, as before. But, as it is not in the plane
of the ellipse, ADBE, which is the wave front, in order to understand more
clearly its eflect upon the direction of movement in the plane of the wave
(which is all that concerns the question of polarization) decompose this force
again, by dropping, from G, the perpendicular GH” upon the wave front, and
joining HF. 'The component, GH”, being normal to to the wave, can produce
no effect in the way of polarization. ‘The other component, H’’F, tends to turn
the movement, as in the former case, alternately, in the direction of the shorter
axis, DI, of the elliptic section of the surface of elasticity, and of the longer
axis, AB.

Observe that if the displacement had been originally in the direction of one
of these axes, there would have been no deflecting force, H’I*. For this lateral
force owes its existence to the inequality of elasticity, or resisting force, on the
two sides of the movement of displacement. But, by the law of construction
of the surface of elasticity, the squares of its radii are the measures of the
elastic forces in their directions; and at the extremities of the major and minor
axis of an ellipse the radii on either side of the axis are equal and symmetri-
cally disposed.

It follows, that whenever a ray of light falls upon a medium of such a nature
as we have been considering, all its movements will be thrown into parallelism
with the two axes of the elliptic section made by its front with the surface of
elastictity. And thus we have a physical account of the polarization of light
by double refraction.

We have, at the same time, the cause of the unequal velocity of the two
waves. For, by the construction of the surface of elasticity, all its radii are
measures of the velocities of undulations whose molecular movements coincide
with them in direction. ‘The two velocities will, accordingly, be to each other
as the major and minor axes of the elliptic section of the surface of elasticity
made by the wave front.

We have also the cause of the polarization of the two rays in planes at right
angles to each other. This is so, because the two axes of the ellipse are in
that relation.

Since the two velocities are both uniform, though unequal, a plane wave is
transformed into two plane waves, by double refraction. Supposing the retract-
ing surface to be also plane and of indefinite extent, and that a plane wave
enters it obliquely, the intersection of the wave front with the surface will be a
straight line, and will advance along the surface parallel with itself, as the wave
advances. The refracted waves necessarily both intersect the refracting surface

CIRCULAR SECTIONS OF SURFACE OF ELASTICITY. 231

in the same straight line. And if we suppose these refracted waves to be com-
pounded of the infinitely numerous elementary waves which may be imagined
to originate in the line of intersection, each resultant refracted wave front will
be a common tangent plane to all the elementary waves of its own kind thus
generated.

Though the planes of vibration of the two refracted rays are originally per-
pendicular to each other, yet the taking of different velocities slightly modifies
this relation. The change is hardly sufficient to be sensible.

pix There are two sections of the surface of elas-
Lan ticity which are circles. Let, for example, in the

figure annexed, the axes of elasticity be OX, OY,
OZ, and let the dotted lines represent the contour
of one-cighth of the surface of elasticity; OP
being =a, OA=d, and OE=c. Upon the same
axes, with OA—d#, as radius, let there be con-
structed a corresponding portion of the surface
, of a sphere, ACB; in which AC, AB, BC are
quadrants. Since a is the largest, and ¢ the least
cones neo axis, the ellipsoidal and spherical surfaces must
sit cut each other somewhere between B and C.
Fig. 62. They will also touch at A. Let one point of the
intersection be at R, and through R pass a plane, OAR, intersecting the spherical
surface in AR. In this, take any point, as N, and draw through it the quadrants
BNS, CNQ. Considering N as a point of the surface of the sphere, the radius
ON=2, and we have

LP—P’ co’ A+4?2cos?B+82c08?C.

Considering it as in the surface of the spheroid, ON==R, and

R2=a?cos?A+67cos’B+c?cos?C.
If both these suppositions are true R°-=2?; whence we deduce
(a?’—2l?) co?’ A=(b?—c’)cos*C.

If a be put for the are OR, the inclination of the plane, ANR, to the axis a,
then, in the triangle CNR, we have

Cos?CN=cos?A=cos*NR cos*CR=sin?B cosa.
And, in the triangle BNR,
Cos?BN=cos?C=cos?NR cos?BR=sin’B sin2a.

Substituting these values for cos*A and cos’C in the foregoing, and dropping
the common factor, sin’B,

(a2’—b?) cos’a=(b?—c’) sin®a

a—b? sina

And

=tan2a. Or, tana=+t

b’—c? cos*a

the double sign indicating two positions for the section, one in the first, and the

29? UNDULATORY THEORY OF LIGHT.

other in the second quadrant—that is to say, indicating that there are two such
circular sections.

The inclination to a of the zorma/s to these circular sections—that is, of the
directions of progress of the waves of which they are the planes—will, of course,
have for tangent the reciprocal of the expression just given; or, if a’ represent
this inclination,

tana! = les fond orl [49.]
e— )

If the wave front of the incident light coincide with one of these circular
sections of the surface of elasticity, it appears, from the principles already laid
down, that the wave can have no determinate plane of polarization. For all
the radii of the section being equal, the elastic forees are in equilibrio in every
azimuth ; and there will be no lateral force to defieet the molecular movements.
if, in the first expression foregoing, we make 6=c, the denominator becomes zero,
and the tangent is infinite, or tan90°. The two circular sections then coincide
in the plane of be at right angles to a, and the crystal is a negative crystal of
one axis. If a=6;:t tana==0, and the two cireular sections meet in the plane of
ab at right angles to c, and the crystal is positive. If a=c, then, since @ is the

mean axis, all the axes are equal and tana= 5 ; an indefinite value, signifying

that the circular sections have no fixed positions; or that all the sections are
circular. ;

Let us now apply the principles we have been con-
sidering to the phenomena presented by crystals cut
across the axis of greatest elasticity, or the line inter-
mediate between the optic axes. In the accompany-
ing figure, let QRQ’S represent one-half the surface
of elasticity, in which SC=a, QC=6, RO=c. Let
PP parallel to RR’ represent the direction of molecu-
lar movement in an incident wave, whose direction
of progress is S/S. Let AA represent the direction
of free molecular movement in an analyzer with which
the erystal is observed. Also let QNOQ’ represent
one of the circular sections of this surface. The
ellipse QRQ’R’ is the section of the wave with the
surtace of elasticity; and the axes QQ’ and RR’ are
the directions into which it turns all molecular move-
ments in its plane. But PP being parallel to RR’,
is already in one of these directions, and hence this
wave passes through without modification; but en-
countering the analyzer crossed upon it, is suppressed.

If, instead of a single plane wave, we suppose
many waves more or less inclined to each other, con-
vergent toward S, and all having the general direction of molecular movement
PP, their intersections with the surface of elasticity will be ellipses whose axes
are variously directed. There are two planes, however, 8QQ’ and SRR’, which
will contain the axes of all seetions made by waves normal to them. For it is
easily seen that, if the plane QRQ’R’ turn about RR’, this lime RR’ will always
be the minor axis of the section. If the same plane turn about QQ’, this latter
line will be the major axis of the section until the turning plane reaches the
position QNQ’, when the section will be circular. Afterwards it will be again
elliptical with QQ’ for its minor axis. It follows that all the convergent waves

.

RINGS SEEN IN CRYSTALS OF TWO AXES. 223

which are normal to SQQ’ and SRR’ will suffer no modification of their
molecular movements; and as the analyzer AA is crossed upon them all, there
will be seen in the field of view two dark lines, or bars, intersecting each other
at right angles in the point C.

Every other converging wave will, however, make a section of which the
axes are not in the planes SQQ’ or SRR’. Let, for example, the plane QRQ’R’
turn around the line LL/, and let KIX’ be at right angles to LL’ in the turning

lance. Then CK gradually increases in length, while LL’ remains constant.

When CK reaches the position SO, it becomes the major axis of the section.
The original position of the major axis being QC, it appears that, during the
turning, it changes its azimuth by the total amount QCK, while the minor axis
changes from CR toCL. ‘There is therefore no position in which cither of these
axes can be parallel to PP or RR’. It follows that every convergent wave not
normal to either of the two principal planes SQQ’ or SRR’ must undergo double
refraction ; and, therefore, in passing the analyzer AA, will exhibit chromatic
_effects.*

lf now the direction of molecular movement in the incident wave be changed
to P’P’ or P’b", there will immediately be double refraction in both the prin-
cipel planes, or the dark bars will disappear from them. But as, in the turning
of the plane QRQ’'H’ round the various diameters LL’, the axes of the section
made by the plane turn in azimuth, it is evident that some section can always
be fsund which at some inclination will have one axis parallel to P/P’.

To take an extreme case, let P/P’ be 45° distant from RO, when it will be
eqtidistant between the axes RC and Q’C. The optic axes of the crystal,
which are in the plane SRR’, will then be in azimuth 45° from the plane of
polarization. Now, since the axes of the section formed by the plane QRQ’R’, as
it turns round LL’ or KK’, do not reach LL/ or KK’ until K or L reaches S, if
LL’ be parallel to P’P’, no light will come to the analyzer in the planes SLL’
SKK’, without being or doubly refracted. The dark brushes will not therefore
appear in the central plane coinciding with, or normal to, the direction of inci-
dent molecular movement.

There will be other sections. however, which will have an axis parallel to LL’
or P’'P’, or to KK’ normal to LL’. To discover their positions, let us consider
for a moment the circular section QNQ’. If at N, in the plane SRN’, there be
a plane IL’, tangent to the surface of elasticity, and if, in this plane, the tangent
lines ¢¢, and ¢'¢’; be drawn—the first tangent to the elliptic section SNR, and the
second tangent to circular section QNQ’—then the angles made by the radius
CN, of the surface of elasticity, with the latter, will be right angles; but the
angle CN¢ wi!l be greater than a right angle, and the angle CN¢, will be less
than a right angle. If the plane QNQ’ turn about CN—say to the position
t’¢";—the angle CN¢’ will be greater than a right angle, and the angle CN¢";
will be less than a right angle. The minor axis of the elliptic section
made by the plane m this position will therefore fall toward ¢’;, from N. So,
it the plane turn toward the position ¢/’¢’’;, the minor axis of the section it
makes will fall toward ¢/”, from N; that is, below the circular section in each
case. ’

Now, LL’ being supposed parallel to P’P’, and KK’ normal to it, let CH CI
be the intersections of the planes SLL’ and SKK’ with the circular section. If
the plane QNQ’ tum about CH, so that Q’ approaches L, the minor axis of tue
elliptic section it makes will fall to the right of H. But if another Ime, to the
left of CH, as CO, be made the turning line, a pesition may be found for it in
which, for a given amount of turning, the minor axis of the section, which will
be to the right of CO, may fall in the plane SHL. The nearer O is to H, the
less the plane will be required to turn to produce this effect. Accordingly there

294 UNDULATORY THEORY OF LIGHT.

will be a series of sections, more and more inclined to QNQ’, and also to QRQ’,
and whose intersections with QNQ’ will differ in azimuth along the are HON,
which will have their axes parallel to LL or P’P’.

By considering the effect of turning the plane about CI, we should arrive at
a similar conclusion in regard to a series of sections cutting the circular section
near the point I, one axis of each of which would be parallel to CK. or normal
tu P/P’. The normals to the planes of all these sections are the directions of
wave progress, or nearly the directions of ray progress; and if, from a point
above AA, the analyzer, lines should be drawn parallel to all those normals,
they would indicate the directions in which (no double refraction of the inci-
dent polarized ray occurring in them) the several points of the axis of the dark
bands or brushes ought to appear. ‘These directions being all more inclined to
SC than is the normal to the circular section, it is evident that the pole in this
case will be the point of nearest approach of the dark band to the centre of
the field of view. It is furthermore evident that the bands are curved. For if
they are not so, the normals must all lie in one plane. But they cannot lie in
one plane unless the sections to which they are normals have a common inter-
seetion—a condition which, from the law of their construction, cannot exist. ‘The
plane QNQ/ turns about an axis movable in azimuth, and the surface which is the
locus of all the normals is necessarily curved. ‘

The foregoing illustration accounts for only one of the dark bands. The other
is produced in the same way, and depends on the other circular section which is
not drawn. ‘The analytic investigation of these changes would be extremely
complicated.

It will be seen that this mode of explanation applies itself to the case of one-
axed crystals with great facility. The surface of elasticity for such erystals
being’ an ellipsoid of revolution, every section has one of its axes in the plane
which contains its normal, and also the axis of the ellipsoid. The loci of the
dark bands will, therefore, always necessarily be planes normal to each other,
intersecting in the optic axis of ‘the crys stal.

The direction of ray-propagation is that of the radius of the wave. When
the theoretic wave is spherical, the ray is normal to the surface, but not other-
wise. The velocity of wave progress is measured by the normal let fall from
the centre of the wave upon the wave front; and this in spherical waves is the
same as the velocity of ray progress; but in waves not spherical, ray progress
may exceed wave progress.

§ XII. WAVE SURFACE.

In order to determine, a prior, the direction which a ray will take on enter-
ing a doubly refracting medium it is necessary to know what is the figure of the
wave surface. Tor crystals of one axis we have seen that this problem was
solved by Huyghens; but the complete generalization of the theory was reserved
for Fresnel.

Could a molecular movement be produced, starting from a single point and pro-
pagated in all directions in a medium of variable elasticity of three axes, the
surface defining the limits of the tremor at any moment would be the wave
surface. The same form of surface (sensibly) would be defined by an infinite
number of planes tangent to a luminous sphere like the sun, moving outwardly
from the body in all directions with velocities such as the law of variable
elasticity requires, when their distance from the body becomes very great
compared with the diameter of the sphere itself. Proceeding upon this

FORM OF THE WAVE SURFACE, 225

supposition, Mr. Fresnel obtained an equation for the wave surface, which is the
following :

Zy2l pe 2 2 P+ 4Bp[e+ypt+e—(av+e) aE
ae [a Tar ( Moldy pte (ed) |Fabe—o. [50.]
Or, (a? +b*y?+ 02”) [er +y+2— (a’?+0?+c’) | + ate? + by’ +ct2? + 7h.
This is an equation of

SN the fourth degree, and
( SS represents a surface of
SS two nappes, or sheets,

inosculating at four
points. Figure 64 is a
representation of this
surface copied from a
drawing made by Mr.
Ferdinand Engel, of
\ Washington city. In
order to exhibit the in-
=) terior nappe, two ungu-

7 lae are represented as
/ cut away; one of the
section planes passing
through the two points
of inoseulation in the
visible surface, and an-
other through one of
them.

‘The form of the wave
being known, we may
apply, for the determi-
nation of the direction
of a ray, the principle
on which Huyghens founded his construction for spherical and spheroidal waves.
Resuming once more the figure employed in illustrating that construction, we
may say let CD be the direction of the semi-axis of
elasticity a—the semi-axes 6 and ¢ being at right
angles to this, and to each other. Upon these axes
let the wave surface be constructed in space, with C,
the point of incidence, as the centre; the values of a,
6, and ¢ being the velocities of rays moving at
right angles to them (and whose molecular movements
are therefore parallel to them) when the velocity in
vacuo is made unity. If MN be the surface of re-
fraction, RC incident ray, and CP the normal to the surface, then RCP is the
plane of incidence. In this plane draw CG perpendicular to RC. CG will be in
the incident wave front. Make RCze1, draw RG parallel to the refracting sur-
face, and cutting CG in G. Draw also GQ parallel to RC. Then when the
wave front has advanced to Q it will intersect MN in a line drawn through Q
perpendicular to the plane of incidence. If the plane of the diagram be sup-
posed to be the plane of incidence, this perpendicular will be projected mto the
point Q. Both the refracted waves will intersect MN in the same line; and their
planes will be also tangent to the two sheets of the surface. If ADB represent
one of these sheets, and HFK the other, then tangent planes passing through
the perpendicular projected in Q and meeting these sheets, as at FE. and F, will
determine the directions, CE, CF, of the refracted rays. It is to be observed,
however, that the points E and F, and therefore the refracted rays CE, OF,

1585

HH

u

==

ae

2

ci

226 UNDULATORY THEORY OF LIGHT.

will generally not be in the plane of incidence; nor will the ray or radius of the
wave surface be normal to the tangent plane.

The three principal sections of the wave surface present each two curves
returning into themselves, as shown in these figures :—

oe

Lia
7 ae

x’ D
Fig. 65. Fig. 66. Fig. 67.
The equation of the section through a 4, Fig. 66, is deduced from the general
equation of the wave surface, by putting z=0, when it becomes—
(Pi +by)(2+y—(@+ ?) + ase? + by+ab?e—,
which may be resolved into the two factors—
(aa? + By? —a?b) (a2 ++ y—c?)=0, 151.]
being the equation of an ellipse and a circle combined. In like manner, making
x nothing, we obtain the equation of the section through 6c, Fig. 65—

=

(Bpte2—Be)(y+2—a)=0; [52]
and making y nothing, that of the section through ac, Fig. 67— .
(ee+e2—ae)(a?+2?—b’)—0. [53.]

This last section is remarkable, as showing an intersection of the circle and
ellipse. The intersection is necessary, because the diameter of the circle is the
mean axis of elasticity—=d, while the major and minor axes of the eclipse are the
extreme axes of elasticity, @ and c. The points of intersection, shown at N, N’,
&c., are the inosculating points of the two nappes of the wave surface.

Since the velocity of ray propagation is measured by the radius of the wave
surface, it is evident that, along the radii drawn to N, N/, &c., there may be two
refracted rays having the same velocity. These lines have a peculiar optical
interest. Their inclination to a, or a, the axis of greatest elasticity, (or the
angle MCN) may be found from the equation (putting S=MCN,)

MN MN ,
CM NO

MN and NO are obtained by making both factors of the equation of the
section, just given, simultaneously =0. ‘The values of x and z which render
this possible are the values of NO and NM. We have then,

g+2—b=0, and aa’+c2’—a'e=0.
from which we obtain, by elimination,
c(a’—b’)
2? = —._—_——, and 2?= ~o-
@—e? a—c

MEN) ce. av P—e ; 5A
NOM ey gaze ba
which differs a little from the value found for the tangent of inclination of the
normals to the circular sections. But these normals are the directions of equal
wave velocity; and ON is the direction of equal ray velocity. 'These two direc-

tions are therefore not coincident, though nearly so.

tans——

a’(b’—c’)

Whence,

PRINCIPAL SECTIONS OF THE WAVE SURFACE. zat

The lines drawn through the centre.and the points N and N/ are however
the optic axes; for it is equality of ray velocity which makes an optic axis.
But it is not true that the two rays whose velocities in CN are equal, can spring
from the same incident ray. Herein there is an important difference between
crystals of one axis, and those of two. In crystals of one axis, when it is pos-
sible for two rays whose planes of polarization are transverse to each other, to
have a common path and common velocity, they both proceed, or may proceed,
from the same original ray.

This is not so in crystals of two axes; and what is more, no single incident ray
of common light, in this class of crystals, can give a single refracted one; for
there are no common points of tangency, in which both nappes may be met by
the same plane.

If a tangent plane be drawn to the wave surface parallel to one of the circular
sections of the surface of elasticity, it will take the position of AD, DB, &c., in
the figure ; and will be tangent at once to the ellipse and the circle in the principal
section through the axes.* If, then, (in the same figure,) AB represent a refracting
surface, and N’C a ray of common light incident at C, in such a manner as to
take the direction CQ’” within the crystal, for the nappe whose section is cir-
cular, it will yield another ray, CP’/” for the nappe whose section is elliptical.
These two rays will be polarized in planes transverse to each other. The
directions of their respective molecular movements, and therefore the positions

‘of their planes of polarization, may be inferred from the following considerations.

The circular form of the section QQ’Q”Q", shows that the velocity of the
rays belonging to that section is equal in all directions. The molecular move-
ments must therefore be affected by a constant elasticity. Their directions must
accordingly be invariable. In order that these directions may remain invariable,
while a ray moves as a radius vector in the plane QQ’, &c., they must be
perpendicular to this plane, or parallel to 6. Accordingly the ray CQ’ is
polarized in the plane of the section. The other ray, CP’, is polarized at right
angles to the plane of the section.

The radius, CQ’, of the circular section is normal to the tangent plane AD.
For the angle CQ’ A is a right angle, by the property of the circle. And the
wave surface on opposite sides of the plane of the section is symmetrical. The
molecular movements of’ the ray CP’ are, therefore, im the plane, which,
passing through the ray, is normal to the tangent plane. Or, if we draw a line
joining the point of contact with the foot of the normal from the centre, this
line will be the direction of molecular movement in the ray.

The proposition just stated may be generalized, and extended to all rays. In
the case of CQ'’, the point of contact and the foot of the normal coincide; and
any line drawn through Q’”’ fulfils the required condition, leaving the direction

* The truth of this statement may easily be shown thus: Suppose ordinates to XX’, ZZ’,
to be drawn from P’ and Q’. Let x and z represent the ordinates from P’, and 2’ and z’
those from Q’. It is evident that the angle at C, where the tangent BC intersects the axis

BC h ae
Ce Also, that the same tangent =
Put CC=k, BC=k’. Then, by the property of the ellipse, we have—
eo Cler beh 2! 02. kiz—a",
Hence, k(2’/—x)=b?—c?; and k’(z—z')=a?—b?.

Dividing the second of these equations by, the first, member for member, we obtain—

ki(z—z') a®—b? >, __v—b? | = ab?
meayT rast or tana 5 ; and tana—-} A To

But this (equation [48]) is the tangent of the inclination of the circular section of the surface
of elasticity to a, the axis of greatest elasticity, which is the axis of x. It follows that a
plane which, being normal to the section through the inosculating points of the wave surface,
is tangent at once to the ellipse and the circle in that section, is parallel to one of the circular
sections of the surface of elasticity.

. . . 2 ra
of x, which we will put =a, will have for tangent

g/—r

228 UNDULATORY THEORY OF LIGHT.

indeterminate. We have scen, however, that the direction is, in this case, fixed
by other considerations ; and it is furthermore demonstrable, that, as the point
of tangency approaches Q’””, the line joining it with the foot of its correspond-
ing normal approaches perpendicularity to the principal section; and that, in
he limit, when the two points unite, the perpendicularity becomes absolute.

In the discussion of the tangent plane AD, or DB, drawn parallel to one of
the circular sections of the surface of ‘elasticity, Sir William Hamilton made
the remarkable discovery that the tangency is not confined to the points P and
() in the principal section ; but that it extends throughout the circumference of
a minute closed eurve, sensibly circular, of which P and Q are only two points
of the circumference. The point N’ is, therefore, the vertex of a conoidal or
umbilical depression; and all the points of
the circumference of the circle of contact are
equally points in the wave front to which CQ!”
is normal, and which is parallel to the same
circular section of the surface of elasticity to
which the tangent plane is parallel. The
annexed figure represents this little circle.
As, in this, CQ is the normal to the circular
section of the surface of elasticity, and CN*

is the optic axis, we have—

2272 B—2
tanQC X—tana’—=+ i Zs se , and fen ee ee 5
a—b ona

==
=a
Whence tana/—=- “tanf. [55.]
a

In anhydrous sulphate of lime (anhydrite) in which the doubly refracting
power is uncommonly great, the ratio of ¢ to a is .9725 to 1. The value of £
is 14° 33/, from which we deduce a/—=13° 41/11”. And P—a’=0° 22! 19".

A general expression for the value of 6—a’ may be found thus:

Oe /
tana

a
tan—tana'=(* -= 1) tang ==
c c

sing sina’ a—esina!

1 /
. . a—c §1na
sinfcosa! —cosfsina'—=-—— /
a ACOs

a
é a
And sin (f—a’

a—c.
cosa’cos8——— sina’cosf
c

; “sina! cos. [56.]

Tn so far as the variation dependent on the trigonometrical function sine’cos?
is concerned, we may easily determine the outside limit. For, since a’ is less
than f, sina’<sinf; and sine’cos8<sinfeos?. But when sinfcos/ is at its
maximum, cos*@—sin?#?—sin’45°—4. Therefore, sinfeos?—4 also. And
sina'cos? is always less than 4. Hence, the sine of the angle between the
optic axes and the normals to the corresponding circular sections is always less
than half the difference between the greatest and least axes of elasticity, divided
by the least axis.

Inasmuch as all the points of the little cirele QgPp are in the tangent
plane, it follows that, if a ray should be incident upon a crystal in such a
manner as that CQ should be its direction for one nappe and CP for the other,
neither the ray CQ nor the ray CP would be confined to the point Q or P, but
both would spread themselves along the circumference QgPp, until, by blending
together, they should form a hollow cone. And as, at the umbilical point, the

* The letter N should stand at the centre of the conoidal depression in the figure.

CONICAL AND CYLINDRIC, REFRACTION. 229

tangents to the two nappes intersect each other, the direction CN will be the direc-
tion of a refracted ray, which will correspond
to different incident rays for the two nappes.
R. The annexed figure illustrates these proposi-
tions. Let ZZ’/XX’ be the section of the wave
R’ , surface through 2, z,ora,c. Let APQ be the
s linear projection of the common tangent plane
of both nappes, and N the umbilical point.
Draw NA’, tangent at N, to the circular sec-
5 tion, and NA”, tangent also at N, to the ellip-
x7 tical section. The radii of the wave surface
Fig. 69. being the measures of ray velocity in their
several directions, as related to an assumed
unit, which is the uniform velocity of light in vacuo, take AD, equal to that
assumed unit, and from A, A’, and A”, where the several tangents cut the
axis ZZ’ produced, describe the ares aa, aa’, aa’. From C draw tangents to
these ares, CD, CD’, CD”. And from C again draw the perpendiculars, CR,
CR’, CR”, to these tangents.

RC is the direction which an incident ray must have upon the surface ZZ’
of a crystal cut perpendicularly across the line intermediate between its optic
axes, (which is the axis of its greatest elasticity,) in order that it may be re-
fracted to P and Q;—a case in which, as we have seen, it will be refracted
within the crystal in a hollow cone. At emergence (if the second surface is
parallel to ZZ’) the emergent light will resume its original direction; and, as
this will happen for every point of the circular base of the cone, the emergent
beam will be a hollow cylinder.

The lines R’C, R’'C are the directions of incidence of two rays, of which the
first will send a refracted ray to N, belonging to the nappe whose section is
circular; and the second will send another refracted ray to the same point, be-
longing to the nappe-whose section is elliptical. Each of these will have a com-
panion refracted ray which will not go to N. The companion of the first will take
the direction Cz, found by drawing the tangent A’z to the ellipse; and that of the
second will take the direction Cz’, found by drawing the tangent A’’n’ to the circle.

The rays refracted, to N will, on emergence, resume their parallelism to the
incident rays R/C, RC, and will therefore be divergent. Now, if it be con-
sidered that the umbilical points, N, are conoidal, it will be perceived that any
plane passing through CN, will furnish two tangents like A'N, A’’N, and there-
fore two incident rays, which will send corresponding refracted rays to N. It
will accordingly be understood that a conical pencil of convergent rays, incident
at C, will produce a conical pencil of divergent rays at its emergence from the
opposite and parallel face of the crystalline plate. Also, though the incident
cone of light be a solid cone, the emergent cone will be hollow. Tor, from the
graphic construction by which the direction of refracted rays is determined, it
is evident that none of the rays of the solid incident cone are refracted to N,
except only those whose incident direction is R'C, R’C, &c., in the several
azimuths around ON.

These propositions were deduced by Sir William Hamilton from the equation
of the wave surface, before any phenomena of the kind had been observed or
even suspected. At his request Dr. Lloyd made a careful study of a erystal of
arragonite cut in the manner just supposed; and the restilt of his examination
confirmed the theory in every particular. The success of the observation requires
very delicate adjustments. Mr. Soleil, of Paris, has since constructed a small
apparatus to facilitate the observation.

When the emergent cylinder or cone of rays is observed with an analyzer
like Nicol’s prism, one radius of the circle disappears. As the analyzer is turned
in azimuth, this dark radius changes position, advancing in azimuth twice as

230 UNDULATORY THEORY OF LIGHT.

fast as the analyzer. When the analyzer is in azimuth 90° from its original
position, the dark radius is in azimuth 180° from ?¢s original position; when
the analyzer has completed half a revolution, the dark radius has made a whole
one. This singular fact is, however, easily explained. 'The analyzer suppresses
that ray on whose plane of polarization it is crossed; and the planes of polariza-
tion of the rays in this small circle are, at opposite ends of every diameter, at
> right angles to each other. If QAPA’ be the small
a circle of tangeney, Q being the point of contact with
the circular section, or the foot of the normal, we have
seen that the molecular movement from any other
point of contact in this plane must be toward Q; that
is, the movement at g must be in the direction gQ,
, that at r in the direction 7Q, that at p in the direction
hs p, &e. Suppose the direction of molecular move-
“ment in the analyzer to be AA, parallel to aQa.
The vibrations in the ray at @ have the same
direction. The analyzer allows that ray therefore
_£ freely to pass; but it is crossed on the ray at P
Fig. 70 whose direction of vibration is PQ. The radius, CP,
will therefore be dark. Now let the analyzer take a position in azimuth A’A’,
parallel to a‘a’, tangent at 7. Draw the diameter 7Cp. Draw Qsq perpendic-
wlar to7C. It will be parallel to a’a’, and it will be the direction of vibration,
of a ray at g. The analyzer in the position A'A’, is therefore in harmony
with the ray g, and it is crossed on a ray whose molecular movements are
in Or, at right angles to Qg Jom Qr, Qp. rg. The angle Qpr is
equal to the angle Qqr, since both stand on the same are, 7Q. And the
triangle vgs is similar to the triangle Qpr, the one being right angled by
construction, and the other because it is inscribed in a semicircle. The triangle
rgs is therefore similar and also equal to 7Qs, or the are Qg is twice the are Qr.
Draw the diameter gp’, and join Qp’. The angle gQp’ is a right angle; conse-
quently the molecular movements at p’, being in the direction p'Q, parallel to
Cr, and at right angles to gQ, or to a'a' or A'A’, will be suppressed. In turning
the analyzer in azimuth, therefore, from AA to A’A’, or through an azimuth
measured by AA’=Qr, the dark ray has advanced through an azimuth
Pp'=Qq=2Q7, which was the point to be proved.
In the equation of the wave surface, if 6 be the mean axis, and we make
c=, we shall have, after reduction—

(PP? 1PYy+br—eb’) (ey +e—b’)=0. [57.]
If 6 and ¢ remain unequal, and we put b=a, the equation is—
(P2t+ey+er—aec’)(2+y+2—a’*)=0. [58.}

These are both equations of a spheroid and a sphere, touching each other at
the poles. The first is that of an oblate spheroid circumscribing the sphere,
and answers to the case of a negative crystal of one axis. ‘The second is that
of a prolate spheroid circumscribed by the sphere, and answers to the case of a
positive crystal. The case of quartz, so remarkable on other accounts, is pe-
culiar also in the fact that the two nappes of its wave surface are not in contact
anywhere. ‘The ellipsoid is entirely within the sphere, and there is no direction
either of equal wave or of equal ray velocity.

These equations suggest the geometrical relations between the surface of
elasticity and the wave surface. The larger diameters of the one are at right
angles to the larger diameters of the other, and the smaller have the same rela-
tion. For crystals of one axis, the surface of elasticity is an ellipsoid of revo-
lution. If its form is prolate, it generates an oblate wave; if it is oblate itself,
the wave is prolate.

The causes of varying elasticity of the luminiferous ether within crystals are

CONCLUSION. 231

not well understood. They are dependent, in some manner, upon molecular
arrangement. This is evident from the fact that variations resembling those
which naturally exist in crystals may be produced, as we have seen, in homo-
genous bodies, by heat or by the force of pressure, flexure, or torsion. So deli-
cate a test does the polariscope furnish of any inequality of temperature, stress,
or mechanical force of any kind, that Dr. Brewster has suggested the construe-
tion of chromatic thermometers and dynamometers, founded on the principles
we have endeavored to unfold, for determining differences of temperature, stress,
or pressure too slight to be easily measured by ordinary instruments.

CONCLUSION.

In the review which we have now taken of the applications of the doctrine
of undulation, we have encountered no optical phenomenon of which this doc-
trine does not furnish an explanation; we have discovered no legitimate deduc-
tion from it which has not found its verification in nature. We have seen, on
the other hand, that it has served occasionally to point to facts of curious
interest previously unknown, which have been subsequently confirmed by the
experiments which it has suggested and directed; experiments which require
for their exhibition adjustments so delicate and conditions so difficult to secure,
that, but for the clew it has furnished, they would probably have remained forever
unknown. This doctrine rises, therefore, above the level of a mere hypothesis; it
fulfils every essential condition of « true theory; it explains all known phenomena;
it anticipates the unknown, and its predictions are corroborated by experiment.

Moreover, the simplicity of the connecting link by which it binds together
phenomena the most diverse in their nature, is almost without an example in
the history of physical theories. In the words of Fresnel, “in order to caleu-
late the so various phenomena of diffraction, those also of the rings produced
by thin plates of air or water, or any other refracting medium, refraction itself,
in which the ratio of the sine of the incident to the sine of the refracted rays is
that of the lengths of the waves in the two media, the colors and the singular
modes of polarization presented by crystalline lamine, it is sufficient to know
the leneths of undulation of light in the media which it traverses; this is the
sole quantity which it is necessary to borrow from experiment, and it is the
basis of all the formule. If we attend to those intimate and multiplied rela-
tions which the theory of undulations establishes between phenomena the most
different, we cannot but be struck at once by its simplicity and its fecundity ;
and we are compelled to admit that, even though it had not the advantage over
the system of emission of explaining numerous facts absolutely inconceivable in
the latter, it would still merit the preference because of the means which it fur-
nishes of connecting together all the phenomena of optics and embracing them
in general formule.”

It is not, indeed, to be denied that some embarrassments still attend this theory.
There are physicists to whom the phenomena of dispersion still continue to be
a stumbling-block, and the differences of opinion which exist in regard to the
true relation between the direction of molecular movement in undulation and
the plane of polarization of a polarized ray have been pointed out in their
proper place; but these difficulties are such as, it is fairly presumable, the
further progress of investigation will ultimately clear away, and are\not sufi-
ciently serious to impair confidence in the substantial truth of the theory as a
whole. At any rate, whether this theory be received or not as a true represen-
tation of the operations of nature in optical phenomena, we are compelled to
accept it at present as an instrument for combining and systematizing our knowl-
edge of these facts and moulding it into a shape worthy of the name of science;
since, if we reject this, there is nothing left us on which to fall back which is
capable of rendering us the same service.

INDEX TO LECTURES ON THE UNDULATORY THEORY.

Page.
Aberration, stellar, velocity of light ascertained by means Of..--.-.........--2.cceeeseeeceeeeeee ees 122
Absolute lengths of undulations, how measured; table of.....-.....2.-0c0scceecccanenecc-eceee--e 170, 171
Apate; PeculiaMpropenty Ol ec sate ees aa clocd canae sina Aawletslecielete sresige he te Mee ERO ne eeeeee 132
Airy's Spirals 52. caeeae stiasaasclce~sals -iscin coh i eraasen cee eee ae econ eels ee See Se ee eee Ree eee aoe 136
his: “quarter-wavelamina”. 22... 25. to. Sescs ses anoeemeceesnece Varsha doridea saeco ee eee cee 139, 206
Amountiof light reflected'at any incidence. -< .J2. 222-60 sees sees aealson a2. -becteaceesaeeeenecce ee: 194
polarized at GOs; sadcceelngia acces cee Sescicks sessise os cae emo enee ere 195
Analyzeridefinede: a5. .- Sooo no Se Sacto toticeiecelca siaiemeute <miacne ae Coens eee eee 133
Angleiofiincidencets /Fa5- sso 3.52.2 sae see eae eee eral Se ee ere ieic crt cl See e eee: eee 108
OfSEIMACHON = <ctes sce aiois 3 So a ala sate eiiaeiee elie eetaieteeiae eee ela oe eee reece Seee eae eeeeeee 108
Otgretle comics. 22. cares ce: 2.csid redhat men mone eae eee ee nee een eee J cleteisec= 108
limiting Hinttotal retlectiones =../.isa2 faeisk ss aoc ac ayeiel a yecte e esto tia Soe = EER Ae eee 138
polarizing, Brewster’ slaw; Of <j2cja:.sa. silicosis niet ese eis eae ae eee eee eee eee 128
between optic axes and normals to circular sections of surface of elasticity ....-...-.---.--- 228
Apertures, minute; produce, diffraction: uss -sosas ae Secs sen ae Seek acecee ee eele sie aon meee eee 114
anna experiments; within aitto. eee ac sane le aif eee cece eee meek cet sees cee eeeeaee 179
Apparatus, Polarizing. —. cctiesacccaccet seca s eantis feoiclowacieaseacie Hee Cee ene sccewen cee seeeenete 130-32
Avaeo; his discovery ‘of Colors inspolarized lights. acc ie osscsce iis seceees sehen 2 1 eee = sees 132
Of atmospheric polarizations: -o22e sce lex s ee ee eee omen nace eeeeeeeeee 143
his experimental comparison of the velocities of light in air and water -...........-..--.---- 124
interesting.experiment (by, in interference). 2-542 sale eine ee seeeniincacee s=seaaeeeeeee 171
his:interference prism. <.2:2 sa as cerajale oe aisinislesSe ele wicia ws cna ne coe Cale eee ee RRR eee Se eee 170
Atmospheric: polarizapion’s © 5... 25.2022 och no seta tasne ceteee a ak ines Soe eee ae eo er eR ones eC 143
neutral PointsOf,...25- oo asexc se oee ain sameecineioseupe wes Sees eee een ae eee each eeeeie 143
ASXESNODUCH OF CLYSUAIS 2o.cc een ccecinas aie ws Selec ci sece a toe ees eeesicsmeseeemee eee omens 115, 139, 216, 227
ACINUTHI ES eiyck = bia <alsalseteloer clae sician Sate See caeeiaa Sut brie elas ae ee Oe a ee eine a eee niaee ome eeere li7
indeterminate in vibrations/o£ common light <2...0 sc: 2.=.-ee\ceiac astm oticieeinceie ee eine stots oe ciemcieteta 165
of plane ’of \polarization changed by reflection.) 5-2-2 .4.8-e- a0 escece ec ceee ese settee cone 195
Azimuths, relative, of vibrations in double refraction..........-.....--.- bewa binceaskiccdemeeaearece 162, 22
Bartholinus, Krasmus, treatise by, on.double refraction... «. 2. sc-cc0cssceace ane cesses sccm ac cmacen's 114
Biot, his discovery ‘of rotatory polarization in liquids-. 2... 2s. .2..2 scccss ademas a acteaeesceneee. 141
Bodies, opaque, produce diffraction fringes in divergent pencils...........---------.------------ 114, 175, 179
Mintte, bright frin Ses in Che; SHAd OW Ole = acya's oral la: a asaiere na nies acteretsiere areal me staiae Saieimstestarse 175
elastic; impact of: =i. skorts jek tee eas Ae cee eicin be kinse cb ace ee ee eee eee cee ne eae ee 158
body vibrating, undulations produced by, Ajmielastic Muid) ..<....< 5 <is:stejo 01 oie cre a mnisinie Soe te pe leieisie eee ectate 151
Laws OFS IMOVEMENTS: ood socio sss ohslsclsisins ocecjeiccsamlaccees abe cee cine e satens see 146-51
Boundaries of: shadopyss wy Suan se) <: 2c cies cje ciicfe sami so Se ee cieeetls sees eee deen ene ee 180
of reflectediand retracted beams a < sac as cqieceaci2e eeamineamoaee on -eeeaeeeaee a eee eee ane 180
Bradley, ‘aberrationiof theistars'discovered by a.22 22 dso de dee cies ewe cabs eniteccemeoeem sect hee see © 122
Breadth; of diffraction fringes: measurements Of. «<2. ct scicciscc neeccine Seis = cersialepseis mele mines ecrereeeerne 170, 174
Brewster, hisiaw for polarizinsangle ys 22050 cece coc aiceceinie/ oo Seinwiomels oceeoeemeaeeePeseeeeeeee 128
discovery of two. axesiin crystals 220)... 52s ecibsenincedets cates cies Gecceicecseseeemiele 139
Of coxedyinesiin: file Spe Cir Mne 2 eta 2a nea a e-em ie =)= oe aici ee eee 126
OF TINGS IN QUARIZtscse fas cccs HU eee ccccnn nc oo ames Sonera semen eaneacmae 135
of polarization by heat, pressure, torsion, /&C~.- <=) << <j. sce iso se sees ee seine 140
InvestiPauons Of elliptic: polarization... 3. .oc%cc.c fois ejees io eeeciesccaaa eat ce ate eecee ee 138
experimention colorsof thick plates 2.2. acces ee on cntainelne see mioas Seen eee seenioe 120
interesting experiment on reflection of polarized light... ...... 22... 502222 seccs cies sees os 128
Brushes, dark, sceminithe rings/or crystals. 225-2 2c cece Se cme eee isieesieie eee 135-40, 214-15, 222-24
Bundles of class plates'used ‘as polanizers!s. 2.22. tle eslan toc ent aca ateisieee eecmamee cee seem eceece 130
PHGIT Tran sparenCy;= 2.22122 ice \1e siesicicsa secs sees cis eee ee acs iaeee 131
Case’of failure‘ofEresnel’s formule forreflection.- <<< == sen teete ee eeees eae erenene= meee == 138, 196
Cauchy, his investigations of dispersion 155-6
Causes of varying elasticity of the ether in er 230
Chinge of phaseiof undulation produced by reflection. -- << 22 < see cc~ sclcemseeceieiese seen isieieiete = 196, 199
of plane of polarization by CO spe Scent eee secret eee eee eee er eee eee 195
of azimuthantvibrations-of Common! Weht © <sicj.scin.sc:= so oco-stseimnaaislewisie Sele eee ee emesis 165
Chromatic experiments, movements of the planes of polarization in .........-....-..--------------- 206
Chromatics of polarized Woht. oe sss ea nctae rama sa sewn eesienia emotes 'emisie aa ae eee tee ie 204-15
Cincwlaraperture, GifMactOn IDijaen ~~ 2 o= e ee cise seis Sle cia|-ealn cise aise siareja acta cle)esre ee Se eee eee 178-80
SechiOnsiof BurtaceOh elasticlhy-e =o. cence alone < ose wlnesis me ciemee cna coat mee eee eta ota siete te 221
MOVMIALS TOM tOe sae ay cee ne ieee miei anes Semel cis aleloe tae ma ee ee eee ener 222
polarization produced by Biresnelis Thom Desessceccnc ce siesoos seman ciece seco seer een case == an 137
by. Ary’s \‘quarier-waverllamina ia: ss seciecwectewn coco rwisasine eee soeee eee eee ee aaaas eer 139, 206
Cirenlarlyspolarized light, nines: seeniin distorted <a. 5 -the ecto o- = onic eee anne aamneaenema=ecee seme sie s 139, 211
Clock apolaryor Wiheatstone bloc = sate tan mecleisatete is eset tae atm claie ee te alae ataiatate ellen etal ote Sea aera tor== 143
Goldiandiheat,;polarization produced: by; <.-<\-csa6 die cas sisieicinin a1-1ny>1= a setalnls cnleilo oe we wajeaem ee emieslerel= =e 140
Color‘and'xeiran cibility; mutual relation betweencs co. ccccc ec cence acme soe mnleelesieeeeee ee see ae aie 111
Colorsioftthiniplateste. 222-2052 2 elerlseeccece: Secucsise doe reties tick ccecseeceweseeereneme sein 118-20, 183-87
ORSCHI CK On Gi oe ois coin Sse wig ee meee cee ale ee em lanic tbisis a Siaicictele See eee einer eines aos 120, 187
of cry stallinelaminee:in polarized light. <2 cece cee. ane e's acnen seneaeneeemereere =e 132-34, 205-10
of cryptalsicutiacross the axis:<<: 2222 sila=ascia aes see = seers reece 134-37, 210-15, 222-2
of quartz do. iss See eee Se eee ele niainiat= sis siataetela e ente aetetetee teeta isla lar 135, 211-12
of the Spertrim = case steal Janina bade acsae alate ciel esate wsinia © a aleetelelametetetatsteretatstnin.-((elataie)ei= rate dil
Offsuled isurtaceste 22 2i.<ceis Sac joss <p ceiai le toate csteleeainlelsie(cle elsisineatemiesiaeeieys=sh=—s =eeieeicars 183
thicknesses which produce, in crystalline plates... 2.2.2 ci eeininie once eae e ee eene con 133

INVNO WON S TID PS see cissac nes ams cicene scisemetetemeseisict Saheeaestsees ahitedtnwad idlecereeee lig

INDEX. 230

Page.

Common:light,jazimuthsiof vibrationminss <2 c.< sae iasesaie a ieaenint icc ciscwccceecceciscecceacecces cece 165

ANLOROLEN COs aaam naan tases aaaltin lalelesa ale wisn Janie eianetsalseiceccecise siesiactemiiccicisle 169

not polarized-by--total reflection s-2cccmaces cote cscecisccas oceecacecessstsecseeescses 138

CompcnsatonofeMr iy J amin see miso sce cose = pie se Slesfuia(oiale = <lale Nac ccieen cous Seseesseeccaeeas paeaeee 199

Compound)\natureiof lightiannounced by N6WtONs.- <2 monc cnn cos se sce eceeecccsascsesccesiscccites dil

Conclusions of Mr. Jamin on changes of phase by reflection........---.--..-..------------2--e ee eee 199

@ondensation.andirarefaction: waves DY sas cecsns ialsiaieislo we jdme yale oi mialaiewie siemicisc sc dame e ee sere cm amieas 153

Conditions necessary to produce color in crystalline Jere pee ROU AGE RULE 21 TENGE SS aoe Dems 204-5
@onicaltandycylindnicalireiracton = cca sade a a's 21 aia mterefalo ae ae er siara)= ae cian ela cra istele ee nicialo (nent eer seein 228-3

Crystalline for m, modifications of, how related to rotatory power ..-.-. ...---....------------------ 135

plates i inspolarized lights sae oe ace wae teieseroceeee clea e Seales asain siccle/-ise aes 32-34, 204-15

at oblique incidences See Rare Sai ciao ce inane es seas ee ce cane amiss cence tes Se eee 133

EteECtB Ole CLOSSIN Pye arse ateasleiea seis oa = simiateia ewes ta eet = ale < a= a aiaianinecie ie saver 134, 212-13

Crystals,;primitive forms... 5...) s-ssesccesess--c-ecc-se Sea eae Bees Arcee ae shee ae ee 141

ENC IPAlWRCCHONS vee eeeemeanenermccieescenees snassaee mae aan ern aeee anes saeese scree ee 116

OTMONGVAXIS os eyoajes aise ce eiamiaietalowts Sale = wiciae aaicreisieielasemenaer seca sinidaniecas soeeaeee oe eae 115, 210-12

OLLWOIXON saeecemene see reeemesas sees cerer= sence meee eeseetionce sence cnc as 139, 213-15, 222-24

POSitiverand NerAtiverssossacsea soccer waa soa e scien slate secenamecinsla= cacnicdeem es seg scien 116

crosses and rings seen in .....-..--- Stasis atlases eee Sie oe et aietela nae ayaiai ara t= 134-36, 214-15, 222-24

effects ofhealaip onsen ses seaae tesace aaa cieeieisicataaciaa cee meee eae settee aot 141

ClasticitysOssetheTi nts seems a aisteiecise iowa sae oe es anaes ee Near eres ee 162, 215-17

iIndexesiOfrelrachonyn asjcosja0 Sac 7seianssccesescee wel erale re oioteesietestateleietains cle ject siseeiencie ic 116

hemuihedrallssesscec anise sesisis sacs Gesis seems tamies omsswet cigs asec cone seems erase socce ts poss cae 142

Mlamihed ral eeemmees seer risa ee aise se essen erie Saami ee ace eee eee enic ec 135

Wuarvies: Lemmniseates ce tecteriai- acto Seine siafaamistoree ase ermnia = aie Sia facie atslaveia isc Sra leval eels ota eletataepeteierrate a aes ercjey aime 139, 214

allUstrativerofsundulation scsiceetecein sees ale claiciain eS icisins salaicinve wisie aint sie eeee e cera tis tora 153, 166

nodal points Oye ser siacn ele eeises aise eines aieioe jawio wine ai serene erate hepa tetera cSt eee nee 198

Wy. ClOid pVADLATONS HN ete = aacase sain Sa. srel ders ore iasaicnafa a eisisinin,eoiaistsete sie Teac einlatdintar are Saleen see ieee anne 148

@ylindticiand:conical refraction! sssa422-ssanessene cds ecintes thaetes Sheae eo see ee bee Ss oe ee ce mee: 228-30

Dark crosses and brushes seen in crystals cut across the axes.-....---..--.------+------ 134-40, 214-15, 222-24

Markness‘produced by-union.of two.raysof light. = =< << .co<scs22S seen < sols ensn cosccesaeeecensesess 14

Wemominis Kcauseiot rainbow.detected «by Dims s<- 32 s.2<c6 6+ es cere cause ssesnes eee on sesceeses 111

Welezenne’s! eye-plece. =. -<-=--.2ssc00 Samiaeeearinn@sles seme ese ayn alee Po elas eee Sn eeiacetet siete 132

Wensitviotetheminiditerent Me diassisia<eicccecte<ctsosescmscmns.c esse secsesiensss Seeesesae oe ceeemese 158

Menolarizatouvor sMehts soe eecaessh ane Soce = see eras ta take meh as wsccossee eee sane eos eee 206

experiment on by Dover.....-..---------- 22-22-2222 eee e ee eee eee eee ee eee 165

Mesignsin-selenite, colored ini polarized light: <== s24253eesnec 52 cet a seeiec eens eee ceeeece le 133)

Dextrogyration and Tee Opi AMON pMvenOOs «CAG Caja eit ee ee cae ee ee eee eva 135

DIMENSION SOT TAIN OW ae sea a te earn ecayav sea o 22 see ase en Ae cee eine aie eee oie ae ctsteters wieleya 113-14

Miffraction; .Grimaldi's\original observations..=:---=.<S.ceess2si-cceccemehe tees ceseeccsceeeceeces 114, 172

MCASULEMeN TOL irIN PERS wan sees =e ote sec eee eee eco eee Sete emacs ca eae sciejooeensmae 174

Diffraction fringes, produced by opaque bodies gqperally ....---.-----.----------------+---- +--+ -- 172

Dy MarrowrOPAQuelibOGles) sascmammaccisss ae set oc e cecise = cence neces ricctascesee 175

byopaquerdiskiselecacdscfatissee=cseccseeret ont Seeemn secmesnee neces ence ce eue + 179

DyaNarcowalePervunen ac sjac seme semen re nea isa mie cieas eijeee ane Ate orse eiretaciats ie

Dyin UtecincnlaridittOtecese mane aceseese ah as seen ese eecemene a eeee seca se toe 178-80

by annulaniaitoro.<cacesse sce ee cease sock om soem seeen sees oe bene tat ese eee 179

Dye eratin es: ceases scat Samet a astiseeemcicceme cei wees oe tak ease selectates en ae 181-83

MOBSULEMEN tS Olaaseeeeeese eo Scieaseee emt seem cee eee semneetanee = eeere aeecets 176

Miftractioninterferences, tormvor trajectories: 22-2 ..s-\cccscosoc- stecaconacco es sece ase come csie cine 174, 176

WITPAChON BPCCWAr ccs oat esshcetise kan tacskesssscs aces scccsoemenseeesebese! scactcieteceteces 1&2

Mirection-of refracted rays in double refraction: -.<- 22-202 -:-22ccccssessces cece secccs cess eececes 160-1, ced

Miscovery ofsaberration,steMar/axcjctya wats eae ns Smo cece eas SSE Seas eee wa aeiee ase eace wees na

oLcineularpolanization sacisac ss Aaacecedciesisiicss cece acecc Ste sce cites seecicwes Se ee mnie oe 37

of elliptic do. wees Memeeaseassteasstes teccretbec cers cee eascececmacsctocecenecd 138

OFTOtAtONY), ~-OsAcwe ssotesaseisacs sae celeses eso cee ede ee dcke tees ostess esete esse Ss 135, 141

of colorsin.erystalline platesis222ssctedssdcccs asses eccds Jodasee loeb oeelatecees skece ccs 132

of conicaliandcylindric-refractionss<.2<5o22ceccnc secs scse ceo cec sects so cclsseeseecccee ss 229

of polarization’ by weflection.22-s2.2sss6 2280502250 secetse ete ee eeek sess obese ee tees 127

Ofslawaof wemachen ys auc 2) cesta ceehe Sin Ve eee es nia a since Sek Cees ee me few ine ca Reels 109

OMlawnoh polarizinovanele .ottekeecakie tesco ckeees -cobee em encme meee Sense cide hai eine 128

Mislocationsof nodesof component undulations: =< -...ccess cece cewete cet eesiteet eee eeebesceseecc oa 198-99

onningsofcrystals:inicitcularly polarized light <-2-+2 ss-ces.se285 Scien oh cietee cere seit 139, 211

Dispersion, Newton's discover y OL eeepc traf HR etre tere late tals tater ee ome ate ere tee oo ata a craves ee 111

Cauchyisstheoryo te eteetse iced eek ccc let cER ee Shia soeetenatoe ofeiciaaitsiaa’S ee ctceeers 155

Moublewefractione.. = Gs Svecsecccceteeteeressiestasé syeceSetasces sab teskageeest secs sackets ac oeeaeee 215

firstiamention Of setsc-q-25 eee ects ee oe ees Shee ene ade See oe Ss ol a Se 1l4

phenomena Of-ca2245 esac Lente seed = Sees e hee ae She tat Jel SS ee ce 115-17

light\polarized byi2¢=-ceeehaetesetscesseete Steet otek shse set Sekec cece se cea wesc ceeeeeeser 118, 215

direction of refractedraysiins 252 snssc25 cet ec cctesecsessessaeseteson Leosic-ccemsemeeees 160-61, 225

Tesitantiof elastic: resistanceuaeee. csr cisct ms s.c.c nee ctlssieccices sl sctsos sles semswiniemtecesieecisic 218-20

GHEORYZOL wbyn LLUy PNENS aeeeeereescerecemeeucccsuEteeee oem onesie te saw a cee eee meee ser 160-61

by Biresneliiccceaeceeeec nett s See SLeE te etee See ccc c weenie SR eee Memeo sceeicts 162, 215

Dove’s experiment on depolarization of light. ---..-- SEE SL tlhe Stisasbshe sss see eee eeeeeaenine se 165

Warly notions. Oflighte2..-2c-2steeeeeeeelcess. ces Ses Ree tem eee Sotelo tee SoBe tee mate toe see enecee 108

Eclipses of Jupiter's satellites, velocity of light ascertained by-.--..------.---..<...---------------- 121

Mlastictbodies dim pactiOf-wcsc.ccssecteteeseteessenbectetest ostesczcc hace dime stteeeecclias seeeace sects 158

Hlastic uid. hody vibrating:in -ss2ccce sects tes saccccceseesceestccccectecceseeeacorsateccccecess 151

{remors:producedtindehacceeeesses sees secseesescssstccoscs ccesa eee ssieenne sce eeee sees 152

undulationsceneratedtine ssaess<2a15 se cccekewic. a8 ooh be aceacecee asics Wau ee tee casinccc cis 151-53

molecular movements in.......----- SSS sea secs cenlee ee ee ose ee eae ce lecteescdeters 157

Bilasticityagsuriace/Ofe.t.ceosetcccc ment eseareeccamsscescsnccc vce teeneamescee rece atwioes cee see 217-18

equation ate/astahaYett Payatalotatare latevelwtatere'elestolis|al sis Se eee selsis Socee coe eles! escieseescmcien P18

Circularisectionsinc.fsss-cssecassostoctse cect oe senses sceecccsscces cictaseisntel= 221

Vvariations)of;.in erystalsiss.s.2e-ssseseecescece e SoA Soe ae Pera ae soe eee ses 162, 215-20

Elastic resistances, r resultant (0 OR ee ore et a ae eee ne ee A 218-20

Elliptic polarization of light............ Seedcsorss Jase ee ewes cewcsseboekees SaP a Oe ee 138

234 INDEX.

Page.

Elliptic revolution of vibrating body.- << 3.6 5..5-q242 502-2 n nin sane aese = eeeeeeece see eees seen eee ‘ 150
rings seen in t0paz.-- _--. SS S-se.ss eee oos)s cops ssenacmpsisiqscnceninuaceeces aes mclcisat cic oie 139
inverystals of twoaxesigenerally.-.-< 5.5 ---eesosmere ee neeee eoeremeeeaeme eco 213

igual wave and ray velocity.) linestots. <2. es 2 oss ae ceases eee meee eee ene ee eee 226
Equation. of surface: of elasticity 2-2 = en os enna nana etane ese cence eee eee a eielaceia ce eee Q17
of waye surface. <2 ssh cae 2s,3,0.00,nim insta dedislonciton sania en eRe Renn doseeis see Gamer 225
of-interfering or superposed waved! -c.- < a> oa <.2c/ecem mascinain= See se UaRet cee seis ne ee eee 166

of waves normal to each other compounded. ---. <2 seiesce~a--emebemese jesesss acess se 168

Of TemnisCate, CULVES <2ac12 joke c emia sooo ,5 one soe seeeeisianl ae = Se ae oe eee eee oe eee 214

Ether luminiferous... 2.0 2.o:s2 ieee cne~ o= 5 dacwadiawtmeeeeeasaesscee- tens See tee eee ce ceeene 158
Incompressibility, Ofc 2 -- cles sas acre 3s sein seme eee aoe So. > cee eee bee srane as 164
density: off, inidifferentubodies 52... 22.,--...-.qassts sete em esecee emis, eee EE ee eae re 158
elasticity Of, Ansenystalss: o2 5 ooe. nc shee esc emiee és Socelneia 8's 535508, 5,.c SSSR Rees 162, 215-20
Fiuclid,vhis treatise on Opies se 22 S525 oc a2. sania eeicincliscieie sees menace se sciseaieee eee eee eee aeeee 108
Hxtraordinary-TVaysyGODNIMOM a2 ajc < 5.< <.c0:52.2.< -n1e's sisisesisjceisieceselosisineeis stacse seeeees eee as sees 115
Bye-piece; Melezenne!ss. ae 2 oven neces enoe ieee cenaeesieessoow asics aneae-acaa sewer seat eee oes 132
INI COMBS nesta csei5- em cncn sane os eee ne are aac erm eee mies erate stots Sloe ca rate Sieiss le tee ate ee ne 132
HOUPMTALING oe sacs loi oy or0/syars srae ora sob Simin lessee mis siele te jsiotoisy-l=jal=jqyelela.ais|=jale(e 2) eee ee eae 132

Bailure of Fresnel’siformulss:for reflection, case, Of... =< e..cjm onmmmsiace nce, sano cele ancien AOA eee ae 188, 196
Hisures:in selenite, inder polarized light. 2c ...<0 «2-4 scianeigenaneseeec ase cneanaaaceetctaeele cee eee 133
Bixedilines instheispectrums --. <<< 1 .s10..2- <1526,5.5 ce sie aa maceme memecinaisemnictecie ose eetee Be eae 125-27
BRizeau, hisiexperiments on the velocity.ef light .:... <2. ss-<-qaccesenamene ae smpsuae ese Soe eeeeee 122-2:
Hluid) elastic, body vibratn gin. <5. ss si5 a Sree oe ses enynsin geese aise Siomininnin sim iarenieinaiajsis alee eet 151

tremors.produced! in. <2 <2 22sec oses aon sa csanceleacaeneceeneseee et eseecs= eee nee 152

undulations generated in. 2 -s-sccscc sc. sosccaamabe Ssnee ee sae womie= th oleae = meee eee 151-53

molecular Movements ins = oA a5 aie.c ere Giaje se webaum sees waeee cee eeee ee eee 157

Bormuls general, tor resultant vibrations. £25..-..0-c/5.-252 eee cee ace sh eeemeeerke a6 cee eee eee 150

TOM GISPETSION ss «ooo ers ase ees else eas apeinie oo a ER a se eee eee ie ae eee 156

for interference frin Ses sao ssc occas cose mwcye'sic soa an cas oe cee Geet eee se Oee ee eeeees 170

for diffraction CO...) 256 oe scineie seach Some ge Sateen a meee ase ease Bees 176

for reflection: andsretracti onesie. <.6<<.5, an.ociese canoe cea oe et ee eae eee eee 189-95

for Chromatics of polarized Jicht. -....4...= -cas~faeceeseerer cecmcisce-se casaenceee 207-08

for lemniscates in ‘two-axed crystals <<... 6 s< ses sscceesecncnsessccsteoneseseceee 214

Morms: ‘primitive; of enystals << oon. c cece oe ok sso eclne a cncins slacwiee seco eee ee ee ee 141

Houcault, his‘experiments:on:the velocity of dight o- - =<. .2s.e—5-e-550cmes-een4s-5seeeee Soeeeeeee 124-25

EBraunhoter: ‘his: discoveries in the spechum: <<. > 6.5 sos ca nsoqastaneateae ees eeneeeenaesc co noeeneeee 126

Nis: measures: of UNGUAONS 52). oe 2S xcjnnaiein serene meee easeeces wapesuisiememajcateneee ee 171

Hresnel; his analysis of light in the axis of quarta. 4... ..2-s esse causes seceseasaateccien eee secant 1.6

hisirhomph for circular polarizations —...cj--sa0cassaanecoenme, disid'eia'winia cate Se onan ee eee eee 137

interference experiment; With, MiVOLS =; =f2.4-)=.0- cc = .)e oes e ee eeeeeecine eeabemest aeons ee 168-69

formuls for reflection, case of failure...........--.--.----..- ih sed ee here ie 188, 196

equation of the wave surface..........--------=- Breese er eee cee eee 225

of, the surface.of, elasticity: << ~j<6 -<.c2.cn serie sess aiainae <email ete ieee te isis fore 217

theory of;undulation: oi 2 nc nneece ce snccncetenceeciececsaansscccaacted seeeer sere aisceestiee 162, 166

of double. refractiomy <6 zien s 2 apateiae jer cee wance ah cise eee eee eee Ses See ee See 162, 215-24

Eringes of interference; measurement Of « .- 22. ~ 2 <2 ose 2 ow =,2inia.ce sins) aosieinieielejaesteeioe ais eles cs sncsie se 170

displacementiof. . 22 soc 5 cece nt oocecanensccasesnshee secueeEateee ceo eeenae ae

Galen; principle, of the stereoscope:stated DY. -...<.0-c0 2c -cmacm ce seses-as cee Seeeaeensee-eoseeeen= 109

Galileo; his‘experiments on the velocity of Heht<<.-- <2 nna mae sci cocina chciisitaineeaaiseeee ani Ses 121

Glassipiles:used for polarization... ..26<i5-0 3252-00. -ncs esac pocsceteactise uelsedeshe ee eeeneeeeeerer see 130

traNSpPALENCY, Of = 425-32 a. wiewcigo seca geste sisainesetcesmacieesasee selenide sceeteceeee eee 131

Gratings, difiraction produced Dye nee cje05-=6..0ceei sana nee eee Selec see een ae eer Eee ese ee sees 181-83

spectra Od 5) name ttodiclecanecee cme can a Se nsnawe eas sce easiule ake Beneaee eee Enotes 182
Gumaldi, first observer of diffraction...“ 2-5... <c6s0e+-nccmeecsqneccecesceceeemese ees ee eeeaeeeeee 114
Grimaldi’s crests; \difiraction.iringes so-called =). 2<,<.<--<)s ce. 322s ccemmmensisincs eee cage eee ee eerest= 7

Gyration of molecules in circular or elliptical polarization .-......--5<<- 02 sicce aces wcsnneen cctcies= 197

FOsltan bol OPP OSite sos esci2c)sataisis. a gare adisasie sees cs awblalets aciekeres aoe bee ees mec 198, 203

virtualin crystals having rotatory Power. .<.-=-0<e= Sa sie\emnlsis =e /slsclsios'saclesinisisieeee lene 203

Heat andcold, polarization producediby <= 5. -e22- <0 - 2aa= ec ace rican ae ee meee eee eeelen eee 140

Heat, effectsof, onierystals'....<. 2%. a'0%)5:3 ce oiejeelieiedicis Bere de seris eels ae eee -simaetiee eee ete eee a= ae 141

Veeland: spar... <5 5.: ssscsoc bach scsesseasesacecoee sc eeee Eee ee eee eee 141

sulphate. of lime:.2.225-2/sse5,5 Ss \cscndmencies nemeeiseeae re eR SEE EEE ee eee eee 141

Plauberite. - < vss oi0jc.- ocic's 2c nie cseias Abs eeiasie sw eleceeiadlaye etesetogeleioeinc lee ale eielsicetaie= 141

Hemihedral crystals produce rotatory polarizations. .- 0. 1 -eccse ve = Soames cecisseere seites seas eet 142

Hemihedrism;, relation.towotatory power s2=2.-/<s2ssei\-- osc ao teee ee emsioe ee ene eee eee eee eee 142

iHerapathite, Wsed.as a polariscopes. 2a s.25 dace sce wc-s sec osisctishe sass eswinia saneeece nae eee meeeae 132

Herschel, Sir John, his observations on plagihedral quartz ....---...---------2--0-0-ee cen e eee eee _ 135

Huyghens, polarization observed by, in double refraction.................2..2-.2-0.020cse=-05-555 118

his theory of ‘ethereal undulations! oe ore soni. = so sae oe winiaie scicmintin saciasia = eeeeeee aioe eer 161

of reflection andwetractiony= o/s ose <0 co's nice sce nasa cee ase ae eee eR eeeae ae ee Eee 159

of .double-retractioms ss. sts =o isi2,5)5e alas o ste ce So sens sicins SSeS ese eee eee eee eee 160-61

his principle of elementary wave-composition ---.-...<.<cs.02-..cnccince ma aeefninieeiet = sem inie 157

Teeland' spar, form and cHaractersiof 32-\i-.<ocec ce Secc- esc cence soccer cccuscs --ceeeeeee teresa se 115

double refraction Dyce ssjs2ciissises acids fo ato2 a2 waa seetlaraneslgntaa ae seoaeaeee seer 115-17

Impactiof elastic: bodies.< . 41,5. cciscisgagsiemeceetes saath sonssecese soe inate eee eee eaten 158

Incidence, angle Of: ........ccceoc. nc ciseis qcaie cme gules aaa Secs ene om deisjaleie eae Sea ee eee eee ieee 108

limitine for totalirefl ection) Scccscree cose ce Sees eewie ses ec= sosecesosea eee eee Eee 138

Incompressibility of the-ether 2-2-2225. ses-scescee noe oemcse- ©. cone nincieclciaia nie Serer eisiersis = rae 164

Index: of refraction... . <2... 045 25,0502 ab)a<o ase ee nessa S So eisice sicies)se saeco eee amen er sees 109

in doubly tefracting crystals) 222 oe eeysis=-cicc gem ecaace ace eee eee eeerataaa= = aie 116

Inosculation, ipointsiof, in the wave surrace.)...< 5.56 4sseecqence ee sslccncles Biase peeeeeeiieeias =a" /--ce 225-30
Interference; cause of colors'in Newton’s'rines'.. 5. <-<.ga.see<c so mmjcin,noassinegecemenios=so==loc Eee ee 183-87

im ierystalline: plates soo )<jcjjsjaminmisjes aise nisl cielo in eee = === ere ete 204-15

of fringes in diffraction. 4-cclseue «cs. +o sateen eiise aaiei-i2.='< 51s sisters 172-83

does not occur in circularly polarized rays oppositely gyrating..-.-.------------------- 203-4
common.origin' of rays Necessary, tO. = <\iss.ses in sino, cseccsie \acen sae Se aaiels sumies saiaieinaiaierets 168

produced by two slightly inclined mirrors ........--- paeeee micesqans sneer === na Saacioss 168

Page.
Interference, by single mirror... ..--..--.-- 2-2. eee eee eee ee ee eee eee teen ee ee ee eee e en re eee 170
by very obtuse angled prism..-..---.-------------- 2-22 eee ee ee eee eee eee eee eee eee 170
Interferences in liquid Waves...---- +... . 20-2202 ence ence ene eee eet eee ence rene rece eeneeeneee= 162
EME VHEVIES Ol BOUNC :c.< ca wise cia cecal as alaniniel=isieisinia’a m © nimaiajninin ele tainies sine olelatel= = aiclstsie a\=/ata= 163
INBWAVESHOL MPN... is nonin sinsinne Bo elctete ataim = aeinisisteleleieveia\s)a/<is aials\aerelalcis sets apmre sere sates 163-64
measurements Of ditto... 0... 2-02 cence ee cen cetera eee ce ewe ese meee eee s see eenene- 170
trajectories im... 2.2... 22-2 ene nn nn ene teen ne ent ce cece ee nec ce eee e ceca tenene® 174,176
of polarized light -.-..- 2.2222. 222. eee nee nnn e ee cee eee eee en ee ee ee eee eens 165, 204-15
Tsochronism Of vibrations: « — 2. -<.-5~ isis ee oans aieoeininfan ale aielm eeisisianin Seleelnisioeicie asin ene celecenanaecmciae 147
Jamin, his researches on change of phase in reflection.-.--.-.---------------------+--------+---+-+---+- 198
his “compensator? - 2.2.2 steemiccecieciaieewis ona eistsemeiniee oan an eee ewe se ccsieecseeacccacces 199
Levogyration and dextrogyration, terms defined .-----.-.--------------------- +--+ ++ eee sree eee 135
Kamina, Airy’s. “quarter-wave” <<<. .c<-2- 0c <=-- stan mencnaaceeccuenmnnaseamssis see = 33s snlen secre 139, 206
Teaminse:) thins COlOTS 40 <= sa. cene = eee cote cee emetic oes sie seein oo cln ms anniniow win ocsmininiew e/ate meme es 118-20
crystalline, colors in polarized light 132, 204-10
Law of Brewster for polarizing angle-..--.-..--.-------------------- 2-22 eee eee e ce ee eee ee eee eens 12
of Malus for intensity of rays in double refraction.-.-..-.----.-----------------------+-++---+--- 129
of Snellius for ordinary refraction. .....-.-------------------------- +--+ 22ers rere eee e eee 109
PEAT BIOb VADLAHON) << 5 eee es ye octane wia/ ee Nese ae Se emcee net seieleleraein= sta ena aaials 146-51
governing direction of molecular movement.in double refraction. --...-.--------------------- 218-20, 227
Lemniscate curves seen in two-axed crystals ..---...-.--.----------------- 2-22-2222 eee eee eee eee 139
OQUaWOU Olean een sos eelancsniee=ccecccecose Seeceeee aie eee sijene = cee 214
Lengths, absolute, of undulations.......--..----------------- +--+ ++ -- eee eee eee eee eee eee eee eee 170
tablenOtesn ces qe Seek Ae Sais Se ieinioeceear Shain sm eicc cece acento s cee mes cis. sme 171
relative, of undulations of different colors ..----------=-.----------------- 0-2-2 22 ence eee 71
Might; earlyimotionsOf-25- 662 .c2-00222 5 canes scarce es S272 = sesee ce nisaien Soci ss cw nsieeien ene asm 108
BELG OI GO Lape ate oe seca haye ce eae ee a ehais oa oo 2 ett a pei micte Siafele aielaie =e eee Sareea == ise aiele 143
theory of emission of
OPumnGul amu. 2 =-6 7 occe cae ceca ee essere ease
compound nature Of . <0 2a nate cess cease asec ne see soe e nin nee sned Socwasessccmemcimemacee
ISPCLAOWM Of emcee ais 2 siias.aicinan wien ci ae se am ae Sos Seem ee Ae cia eit iene: <feinis = =i=tetalaPa al
VielOCUiys O 8s eee acerca oem CaaS sasaaniainseGaine's re Se= eee aa aeiiemelsemee == eee
polarization of; by reflection.......----------2---- 220-222 - nee es ees sense ccs teec eet ee eee 127
by snetraction:<...). <= anja ase se see a = Ase emiseiec = eeele ein seein = 2a) 13
by: double refraction «..-........--2-20---dssceceson-cee sae seleisioe eo ew eae 118
circtilar and! elliptic Of. ..2..0.026 wis so2 d= coca siere cinisiee oes’ eerie eee stein 137-38
TOUR OLY Ol pe soe irie oe inte staining Se ea Smee eee ele ee teia tem nielaiais sleiaietetntstotatniats 135, 200
aimospheric:' Of. ac s-222 2s aac sors ccie tens aa SoS ee ae ies eaelo se a ae mines aal= 143
depolarizaiom Of 2.2)2.5 poets ain cee soe een ew oe aisle aa Scene ce nica ta etelemicsinle = aaa teiniali en ele 165
Interferences Ob o-oo. acecseccems salsa, cS eseniced Barca ic oia a ee crete ene ee ete ete ete eter =eteinata 165
conical and cylindric refraction of.....--.------------+ +--+ 22-2 eee ee ee eee eee eee eee ee eee 228-3
of the sun and incandescent gases, not polapized .--.-------------------------------+---+---- 131
of incandescent liquids and solids partially polarized. -.....---------------------------------- 131
polarized) chromates Ofe:. q.ce neces aeiticinen nadine Sima aa aeiciale wieiaie Beeson eereen eee coe 204
Limits of thickness within which colors appear in crystalline plates........---.--------------------- 133
Lines of equal ray velocity in two-axed crystals ---.-- ----------------------- +--+ +e eee eee eee eee 226
fxedsinabhe SpeCwuUMiy 15 ee Aa seca an ee cieeccins sree sce Sac ewer seinen ees eine 125-27
in the spectra of incandescent bodies ...-..---..---\------------------ eee ee eee eee 127
Liquids, rotatory power observed in ...-....--.- ---------- 222 ee ene ene eee eine ne ence ee eee eee 141
Liquid waves, interferences in ..-.--------------- 2-222 een ene eee eee ee eet eee eee eee e ee 162-63
Mocol difiractlonunterterenCeSy <2. soc ose/- cin asisitsegeesioacsss sere -ccoeee comes belnigseeite n= ote aa sana 170, 174
Magnetism rotates the plane of polarization ........-------------------------- +--+ eee ere eee ee 204
Malus, polarization by reflection discovered by .--------------------------- 2-2-2222 cere eee eee eee eee 127
his law for intensities of rays in double refraction.-..--.----------------------+--+--++------ 129
Material theory, of lightwo2- 22.2% ses-0csds-c nega cot aciamenicasinnnngs seacee secon anemnre esr enecenees 143-46
Measure ofstime “in vibration. os. 2stJento 2 oan aro nei See isis POS re odio ra See nco ranayelra o Scie aNS 149
Measurements of the yelocitwiof light: 225 sj1o2 22-2920 Jiase-nsoesceeeeen ces ssc-e cesses se secs see 121-25
Omidiftrac tlomitrin Pes cissee soos esses cae ses sis ee eee ieee smlee an nesses) 174
Of interference drin Pesssese= caus. oc oe- en eee eee ee ecemtcisiteeene ae EeEeemo aoe 170
of thicknesses of plates producing Newton’s rings.-.--....--------------------------- 119
Of undulation lengths yo s< ayo oes sa aeiela sense gases eee mee sian= sin Sesser ae 171
Metals, reflection from, produces elliptic polarization. ..--.-.----- aac ic aS sae een eeiae eee 138
Minute apertures producerdi rach Nee oJ 2510s mice on cosa aes) Se saiee else eme emesis cies sisiee a 114,177
Minute opaque bodies produce diffraction........--------------------- 2 eee ne eee ee eee tee e tees 175
Mirror experiment, Fresnel’s, producing interference. .-....--.--------------------------2+ +22 2+e--- 168-69
Mirror, experiment. with single, producing interference...----.-------- Sea hsain mee c= alate es eee 70
MONA 0 ANI ZI Oye eee a ee ae eae sia ae as aise ine a SSS aye eis ercis stein state ste atn/sraisinin mona Sec ese Sees 132
Molecularmmovements, varieties Of <£ 422-22)... 2--4255 face ces. toc egce cece cence esac sina eee THY
SNSBOUN eso ns ase oe Sate re waste saeceeans aceimsanaiacmweaicew = ciSe oo mn nspesieeteter = 162
INWUMINOGUSHWA VEN. £o4ce Secs ter ae Ss roe aa sesiscsmc kine Sale keira s.cle eteeiiare ie 162
in planepolarization)...5<..2 22-2202 Sviaceieno secu 2OhSe cts. alse aea eee eae 215
IDcincularpoOlarizavion:. << <62.2 ec aq-ma-clssee= se S Ss seme Seale mee sialale ela 197
in. elliptic polarization... -.<..-.s2ccsaeituiele tsje's so sew se ease einen testes 198
in doublemeimachlons< scam cs sas Sse a sie ane Daim ainlarse falebelemlotietetete= o1a=is 162, 218-20
relation of, to plane of polarization -.....---.-.-.----------+++---+----------- 216-17
Monge, curious experiment by, in double refraction. ....-..-.-----.--------- 2-22 ence eee eens 116
Motions progressives OL Light... -..0 5 6S i ehepcte a mina. c ope) oraisieinia min siniain so sje in eienie wiamicmslaeisinielewisjemie afeisim = sietais s 121-25
Movements, molecular, in undulation ....---- Fe se ee a ota nee eee eee eee ae ceeeias 151-53, 164
of plane of polarization in chromatic experiments -------------------------- 206
relation of, ‘to:planevof polarization. .....- = <<<. -eicemiaceiscnin vies iene =i'sa n'a 216-17
Narrow: apertures, diffraction produced Dyi- -~.-<.<--c-2- -cceie =e cecninsce ea einme-semseeceseaceceses= 177
opaque bodies, diffraction produced by---.----.---------- cence eee e eee ee eee eee ee ee ees 175
Negative and positive crystals, in double refraction. -......------------- Bee Se ME neat ables «SiS SSIS 116, 222, 230
Neutral pointsumitheiatmosphero.< 2.5. 22e: scescceecie erect smossvetsiceba emesa nates Saeiricin o> cls seine 143
Newton, compound nature of light announced by-.--.----------+-----2-- eee eee e ee eee eet eneee dil
hisiresearches on icolors.of thin, plates =. 2<--.<cisis sicemcesr'ces ses esecemasia= faisiaislacia(senie senna 118-20

Of thick plates! s.. qi cicacicivass Siote(siiaealsteleo’era Berets neieseineeeeos caieiaits 120

236 INDEX.

Page.

INICOMS| DEISIN 27. oS msriemmsaeeseeteisks aieleinjacain/ajeiersimfarainsn'm a'ninia siaya'm Sale/nin = mimiais\aateleimarcioleieieaieteree alee athe aiete ee) 131

Nodal points injundulation.curvess2 ca saa sace oceans tee ee aero oe oe ee en ee Sains 198

Normals to circular sections.of surface of elasticity ..:......--2-s2s-cececci-cceeeeee bees cceecceecns 222

Notions; ‘early, prevalent respecting pe hth see ss a<eas 2521 ae ace Saeco ee ee eee ee er ee 108

Numbers of undulations of light peraécond). .5)...2< 42-222 Sscsc cao se ee eee ee ns 171

compared with those.of sound: 22. sscasccbereeeseeeele-c once el eee 171

Oblique incidences of light, effects\on Newton's Tings... s- 255525 ene sean eee neue ie so | ene Es 120, 184

on:colors of crystalline-laminie.cjacsceseonceeeee oes ee en cenee oe 133

Opaque bodies, narrow, in divergent light have fringed shadows...............-.--.--.------------- vO

Opposite molecular, gyrations, wesultant/ of... 22.22.12. s2sssecse seen econ eee eee een on aan ee ae 203

produce!nolinterference 5-1 e sisaire s tree he ee een a 203

Optic axes-of crystals. Josep ance seisiais as siacels o.ajararate ei ciaiey aie ee ere te eo ae 115, 139, 216, 227

of two-axed crystals, how situated 227

Optical treatise of phuch diye Ase cici.< 2 ain icce ara ee Gin cin anne EST slae ree Oe ne a 108

OD RCO erm ype since sc ciciara an are Srara ciclure erecta sia oats GSO eee ee en ee 108

Ordinary and extraordinary rays, in double refraction....°2-- 52... .gsscse ace eee nw oee ee ae) 115

terms not applicable in case of crystals of two axes..............--. 213

Origin: of interfering; waves! must, be (common... = --s.ss2ecsee 22.22 ha dee Sees See a ene 168

Partial reflection of common light, elliptic polarization produced by.-..............-..--.---------- 138

Pasteur, his\researchesion rotatory polarizationc ssace ee esas Soca Sone eee eee nee oe eee 142

Pendulum vibrations ol... 5.5.2.5 sera Se draaiapct neers stares Sie ct Ne ire en 148

Phase of vibration or undulation defined 22 -= ae. 5ecccne osama bee aaa cme ee eet es eee 150

changed sby-reflection: - 2-22.45 sasedsasecae soe cc eee cue eee eee 198

Phenomena of ordinary Tefraction): = =. 2.c.csscscd a locso seme eenee saa sane eteeanac cae Sco eeeee 110

of doubloirefraction's= 2. smje Sas se cis cecmasiontete ge 6 Some ee eee eee ee ee 115-17

Piles of, glassplates used aspolarizers. <2. 08 sssas ecm meine asehnsee eens eee eee oe eee eee 130

transparency Of, 5 42sec wae iats oes SoU e eee eee eee oe eee ae teen eee 131

Plane) Of INCIAENCEs 22.5.2 seis ss /owie sisiecisiaeee sien nese) aS seo wees eee eae oes eee 108

Of MEMACUONs 22.32.42, -caieisaeae. com qalnes ae rasa eae ReSae sana eee a ee 108

Of POlariZaUon Aa. socom csalatee ee aime iace eines nee mine ae eae seen e eee ee ee eee 129

of ditto’, forrefracted rays'in' double refractions: -s.ase2-cssee-a-2eee esesce se ecco see ee 28-20

changed by reflection. (20.55 2h acce lect odueedeeee oe eee ene eee eee eee 195

rotated! Diy; Magnetism ses <2 sae saaee oases se Soe eee eee a ne eee ee 204

as related to direction of molecular movement.......-..--.....-.---------------- 216-17

Plates; thinycol ors produced DY << wc. sss ose Sosa cer laeeae ice eee tine See gee ee on ne 118-20

thick) (colors; produ ced DY y= .2</o<iciemclacerssalsniste ete een eee oe oe Meee ee en ee nae ee 120

crystalline: in polarizedilight <2. <<. 2shc0<esnoce avecasmescwace laces Sees eee eee secrete 132-34, 204-15

Of. glass, pilesiO£ wsedias polarizers... a2 2. sanscictieansceseleancetee cee eee eee cee ee ee 130

Points of inosculation of wave surfaces q.22. caccs nccisieseeece sosecesecusscseacesaesgesse ese se nee 225-30

neutrals imatmosphere’:.12 << ssads se deseccewsasacsses canweee ace as ace seee eee ee 143

Nodal nnd ation CULVES S320 sao sacre casas eos ceiine aces nee eee ee eee 198

Polar clock, “Wiheaistone Socc. acs pacers ssa sieie icles =ian as Se age ane eee ae ee 143

Polariscopesy, NiGols 22 1s sicmeclomiscacieism secieewive se Crema eee cee ete eee ne eee ee ea 131

DD GlEZSNNG Beces sis iss ot stem okiei- ointcia Daa tahinietaccut smeleseoel aces eo ee ee en ae 132

HOUTMALIN G2 Ata hs fea aaon a Sas SAL eee eae er sree re a em sd Pr epee cnr 132

Polarization of light, discovery Of 2c .c.-.c2 ba stais. sec coe aes seaoe cee eae aes eee ee nee ee ee ee 118, 127

piysical theory Of: <-c22ocec odaiciee so ccig. Ja asios ee Sao eet ee eee eee eee 188-95

ChromatlesOls:s <5) a2 ccteis csierecieaan icin See SaaS SEC eee Soe eee ee ee ee 204-15

amountof at any Incidence. 5.2 .2522can ctciicmisins iso neee e oeceece eee eee eee 195

plane of, defined a 222. 5555 acc deccges coccleseccnes mes anceeeee ee eee een 129

ALMORPNETIC: + (sje, crs k eases earesome Moe Hee oe em eawie eco eee ene eeeene ee 143

LGN Cr 22) Bice naar oe Soto cle Seo aeaeae aoe ee ae cae eee se a ee eee eee eee eee 188-95

GIVE TM AN says anaes sialon cts cisnars Sate ais a Spa Steins close Se 137, 192

OULD Ue. se rape in bse Se etwin ys ASE ee trea Ne er rep 138, 198

rotatory, theory: Of)--2 \sq.ce-sadedsenoscsiesacaaas is cmeeee eee he sees 200

OR QUEM 2 ce a= Sela s o arecra cpiciarstaiscis ie AAS Se See eee eee 135

OPM QUIES |: 2,25 sc.esis ose sed oad cc cane Coe aoe ee eee ee 141

Of SAMS! 2.5. osscis iow sts etches tc ole sl See oe ee OE ee Oe eee cae 142

produced by heat, cold, torsion, tension, or pressure.....---..----.-.---.------ 140

plane.of, changed: by reflection: 322 2222.25 - 2 tsecne needen- eee cee tee e eet ees aoe 195

rotated by; Maenetism:,..22 jee sears isia alee a See eee ee eee 204

Polarized light; properties Of <= 1-02.25. s2 sales saan s/s sae Des ee ee eee eee eee eee Seer ee menace 118-27

colors,of crystalline ‘plates ins. - <2 a acshace. os scccdaeies Sacer eee eee eee 132-34, 204-15

INLETLEKEN CES: Of, iso crayatans Siw sara a capeleie at etic tclai shee ee ee ee Se 204-15

general phenomena, Of; -.~ a istewicisiaisiciescaenid Sm sige eee eee eee oe oe ee ee Eee eee 118-27

Polarizing pilesiof ‘class. =s.Js-2svecee maces saeco caste ak Sapte aisha ee ee Se oe 130

CY C=PIECESe pa sacs Sacto aa amo we Smiacinaeinsicalesia aisle a ee ee eee eee 131-32

MULT OLS fase. Sposa te tearm ami sini arstafeiaiarseata\etataeintmielat siniaielcie Said eae ierals ME ee oe ne ee Tee ee 132

EMG Goo ose ase ome ies mIaae toe oi ra malate cm a rec 127-8

STOW SLED Sil a WHOl. ma aes Aaa osia cial cacstats salnciaaetotelal slo ae ae eR eRe ee eae 128

Positive and negative crystalsin double: refraction.--._-2---c--200c.cbecceeceweccennseeecc+oes- 116, 222, 230

Pressureimparts polarizing properties: to solids... gene misinn asec sna ees ans eee aac e eee eseccee ts 140

Primitive forms of crystals possessing: polarizing power? -\.-- - sesso sncsccewes sce eucen secs sdencems 141

Principle of Huyghens concerning elementary wave composition -..-..-.........--.-0-0------------ 157

Pringipalisections-of crystals... cco t amines mete se tine ae ere ate os SE Soe See ere etre = erate oe 116

Of WAVE SUTIACE:s.< 25:5 Sac clear toeblefsce eae te ae enc dicts A See ee ee eee eae 226

IPTISMALIC SPECEUIM | .:--/---...0-- 2 Soe crck re SER RISEL See RSE GRE Clos coceicke we eee eae eee eee lil

fixed! lines! in... Sjancce eee ceee Nee ete isom es seek ae eee eee eee nee 125-27

Brinm: ‘Ara cots tetas a. <12e arrcis ain reeivro stele Soe ae eee sae ne eta as Siete cle mica enter tec Sloe 170
PVESnel iy ¢ cjayorayo ata asoiej0.50 she wieice Sosts & berecicmieiee oma ae eens ot seme tia keels oe ee eeeeatees acie sio 13

NICO Sh yace eee crinccte e.cecianin ae -emeeeneeteljale nelle Sam ale lain Saree. eee ene ree ae Siar ate erste 131

Progressive motion of light 121-25

Progress of wave and ray in double refraction distinguished. -.-........-.....------------- +--+ +e eens 224

Ptolemy, his expermmentsion-refraction....- .22c.ca becuse ease nes acan seer eens eee ne eee seme 108

“@uarter-wave lamina; Airy s |... <4 5 <00.5 sc oeicctdas cease eccce ere eee reese see e sees 139, 206

Quartz, crystallographic peculiarities of... -. << -22-< sg-ececio = --ce aise neeeueee hence cee esa eeen cee 135

rings Of discovered Dy, WrowAtel <7 2202 se ecclesia a= sistecliaminceemeneinrs sjniceinaina cistelelersiesteiets 135

INDEX. Zot

Page.
Quartz, -Airyisispitals seengin' 5. oss .scemaciaceaaa seas ectesasia cas sasiciacawcieeee Sete ce eee nee 136
MO tao mys 0 lALIZ etd ON ara) eater faiermlaler elemento eicieisin aim siaeiniaiaieisibe teseeia ase eeseeneeek 135
or mrimow. explanaionot iby De Dominis ss.4.c45knesceles-sc~oscecene sous scuccncoes beeeaokl: 11
CANIROI Oi MUGLER oye winte,~ <2 = 4.c\aaie tere ain a minisinteia tate Para nicieis\siniaiopajania/sisiacie.cists Mae he Sees Boe aon ae 112
. CHIMEN SOUS O taeeeete ress Seder an near iaeatatccisscisieaia sible ac oe cians Saas mae ee eicione 113-14
Rarefactioniand:condens#ions: WavesiDY,sccaercnssocareesses ocs anaes ma Scacea abileceee ae se s+ smsace cee 153
Ray progress and wave progress in double refraction ........--.--. 0200-22-22 0e0- ene cee dee ee ceene 224
Metlection, (anglovoire 122 1a ofo.n'o stowinin mieininnloainie sts mysin sie ania lala eilaainiaisjaiaieieims)aiaia/se scie's = Satin alse sine ele 108
Yi) Sin OY ON areata ain iain ial tcin ene mista = Seen rece toe ace cate aisles ee 108
LD G O LV OL et arein sacle lee eiae ee aerate = ia se eee eae a nae e sie as ee Ue on 159
DOMAIZE MONI DY o= epee ae ee ae eels aiac ect eee anelniana casei een ae Soo AGe on Sener as 27
partial, usually produces; elliptic polarization.....--/).50--02 2422s. See cade ceuc connec coee 138
AMONG LAS so <= fete oe a eee eects ws aat= =cicaine tense en Aearea Asoc a ateere ee eee decade sab ae 138
total (does not polarizeicomMOnM GHGS «<2 o:a2,sare acisymansinaicine sciences eas ene s eee chee cece 138°
frominoled. surfaces producesColors) j= 2.0). sc ccjeecemis seek emo ecm eaesce scene vaccine 183
changes plane Of MOlaniZzationis jr on.-\-/aje,4 o2imae cise a ema aoeemetoamaaiy)sccmeoe noes colon 195
changes phase rmundwlamonere a so c.acle sce ciamaaedaee ee eee neice elec’ See oeees «nee 198
restores plane polarization in circularly or elliptically polarized light ....--.......-...... 197
PRCMACHON, ANP OF re <2 oer malian vei a) nelesanis ae te eee eee eee ee aeiey =e eee eee eee nants 108
OL EN GO eee ate teeta ee eos oe eee aa San ae ee ee eo eee ee eee eee one 108
BHC ORs OF ete ete cae eats amine aiaraaa salsettele Riser ete sere eee ae eee ae pean = 159
Piolemiy(siexpenlmentsOMis- eerie = der isascigseecaine2cee sce ce cee Sete eee lee meee 108
Wawa Of etmatatemtatetatiarse sist ia[ai eter) aa sta iaie met Asoe eee wine cocits Selene Soe ene ele SE te 109
CLI CLE KO Lateeers esa eam mie Cie aie le alee ate Se epai Saisie aie sine = ses aoe siceite aie ce nemo ae ketenes 108, 116
PHENOM GUANO Lem amen atom eae are eae eae cise sine sisiee satin os cae OE Ne eis 110
Sey OL a2 CC Diy era eat a=, farers eee Ie aS a ae eras ia te sl Stee ee eee 130
nehticircenlankymolarized by vee sas assent seis aaa = cciccemtases asariee eaters aoe cee 139, 206
doubles tirshumention! of: a: ass acc slemceiasaisenrel ated qeidec bee eee aceon. ee eee oe eee 114
theonyaon Joy, Envie hen seXe swtare ase ei haere oi sad ela arses ore oe 160
THEORY LON, va REST Clee Semen a neo 5s ataiajtey=n Sorel ee eee ee peice Sere 215
MONET OTMOM BONS cS sepa is ere ais harorata tein x ar ararere See ane ee ed ae pes ae 115-17
Planes.onpolarizaionwMny ss. eco A etcese minis oeiae cae ate See te 218-20
direction:olnetacted ray sam 22sec re ctacinsi ose ee een oeimacte See tra eee 160-61, 225
Refrangibility, unequal ofthe: different COOLS -2)s 15 325-cieceede = socisec ees ccne cence vaceen Boeke e LLL
Relation of vibration. 00 umd ul anon. 5 sos a5. = isles, - cra eletadaioiioelee cf Wee ee eee ee ants 151-53
of direction of molecular movement to plane of polarization...........-......222-2---------- 216-17
REsistan cosmo LastlC Ost tamt O fetuses; Aomori ce Liza) ceases EE tee See eee 218-20
Resultant or compounded impuleesimivibtatione <> esecnjon oes ss occ see ee onee ee cc eee ene 150
OL superposed undulations <2 3is.28-e 2) sates aacnce rence onda ea cac eater oae one eee pees 166
of elastie resistances in doable retraction te a=.2— sasceseecsee sce s<cee eee Ce tone ase tee ae 218-20
of molecular movement in double refraction 42 ..0che5 cose ccc cic cise Seecte snes ewocews ces ade 218-20
OL Opposite pyratOrys 1OPCeB as. feito naa eee sab Sea gos seme Na Oe awk oe tee 198, 203
Rovolution induced myibrating Wodies. aso os oc cmeee SiS a maeis sce loicecinrs on nlewele susie seek dees 148
when) circmlariandiw bemellip tes ajc a eiverarae\ spar suiseieismcys-nc aoe Ati Ae see etel eee ache es 150
Rings; colored,seeninithiny plates 2.2 2s secswetatanecuscemaccwes soc eee caseee mete leeches atdceeed 118-20
mvcnystalsim plane polanmzed Hehe: 22/2. acictiemciens acmmesiacas sects. ences eee us each bene. 134-40, 204-15
TOChysials in cincwlarly.polanzed Upht-a< 2sscencn <cececss asccemoscecene sence ictlanece ates 139, 211
CLM C AINGtO DAZ Aare seals Aeleraaiseisisis siete ae See ead Gosek aac ce eee eee een ana 139
Invi WiO-AxeC, Crystals Penenrallivice eon mms selec cin <a <icimoretac see eee Se sores cee jot we Q3
Romer whisidetermination of the velocity of light — 22.42. --0c1edsmcacwccs acne teacenesuebeceess Hancee LEM:
Rotation of plane of polarization produced by magnetism..-...-....-..--.-----202-- eee eee eee ee 204
Rotaionyapolarization iscOvered esaae ac ansAcseccswesoas = seria omam noes seco eee ee SM 135, 141
LSC) GU pe ete oye eevee tx ey Sayed veats ors ateyaiepe fee STEVSere me ete Ett MS oc 135
OROGU CE OND ya CMAN Zie se een se ns aaioecscaisacee ac erica asec eens 135
DbyAlui db ee sens somes emcees oan seme mescianscte Sane Sees a anemic 141
Dy Salts eye eee eee eases se acsaele nace ema: Meee oe SE amid | 142
Rasteurs researches 1M). Jecmrjlaici= ene c es cncs acme eee ce ieee sagen beee ose. 142
The Oy Ol semen mat arate arenas ee ay en ees epee eee eae SU CREAT 200
Rotatory power, how related to crystallographic modification .................0..------------------ 135
Ruledisurfaces; colors seen in efoction trom 122 cjseis cigs nce cece See eeetee seen cc cee cnn 183
NACCHATIMELET SO OLOMISy one awe a ciouia aie sce eee ea ece aces Megas eLe eae eee Mee et eased 141
IMUGE Client Ch Bisa arte sisal as eets sare aerainiays rate et a ae eam Ay era 142
Salishrotatony polarization Produced, DY): c.2:ai<t- sfscisc dele Siecle ones Sears nies Shee ace aleniedis wajsci eso sce 142
NECuons Cine ar, Of SumiaceOr elaShClty< ac. joocchiocmawjenies jo sooaoteet oe vines cee luncne-ccweesSuoee Q21
OLIN CLD Aly OL CHV SUBS fois cte fore Matala sella Jaiaiel dia aia lsjallareisiare gaa elm qcisen eee onanninn ce os CaSO 116
ORHWiEVC SIMI CO ao aaron aiiare asalnieie’siaiayalaiaja alana nine aisle einen arate wie» = wom eo 226
Seebeck rotatory power of liquids:discovered DY se2sask cance lssaosSseetciancee nce Jc. lesions 141
Selenite figures colored in polarized light L33
Shadows, sharp boundariesiol <= <2 2s sce a simineges 180
of minute bodies show diffraction fringes..-.-..... Sen palwelad=laqccio so cece cetera 175
Snellius, law: of refraction discovered py ------.------~---s-ssc--scccee Bee EEE COIEISOHE CDOS. Gop SeSe 109
Solawlipiigun polarized = accom a sel ate) aitoe)s =a eee ee ace ce ine Sumo dee, . eae Lae 131
Ole SiRACCHARIM ELEN a) se tec sere eee at le a ayer a esate chatetealS tm eel YE ara laa 21s See ey eae a 141
Sonorous undulations; molecular movements ti. <. sin\a)d/alsinate ciasivicis Saw cw cles ocichesies ole seeeee ce ceeaie 162
MeLOCIty OF; UNIFORMS ooseporarstayasel=tchelay= ein 'sj5) Ser yeeinye win. wie wm 6 SCI ARE ee ee oe 155
compared: withmehOseOMle tas. Sir ccm alae cec te nin = ajc oases alae 171
DOUNGEVCLOCILY, OL secs a ere asa saci ae ie ae mie wis Soe mere cielclo ala ctor ‘arcs oss 25 ee ee De ea 153-55
BNILETT ELEN Ce SMM io ajadstarats seals Meer iw aioe. ci daisicre ey See a Ss sca ae Se TALE. 163
molecular MOVEMents 1-22. rpecela acme sim cisei= ~sle ls ietelniet <inbiciea ee seeatee ce oe Le Me. 162
Spar plceland yenystalline fonmss 322m ee erm enr seca sam aia/oee nets. eine acsearle eee nee meen | 115
douplemne frac tt ON yas tata a etanimieielel alate aiar= ior sse'eiainwieiesin liens ae sae eee eee 115-17
Opeciray producedsbyidifiractiOn) =... ecmemeeseo =e ecenais=oe ccc ceeenemeneee ns cctee sete osne la 182
MPECuruMesOLAr COONS! OL am seam te one oa ere ne = ne oe ee ei Cision ae See eoee seen 11)
fixe cin Sshimy! S27 cerca aieaa/mco se maee a Aaeiee cine ass sede pinisioees ceca on enon saee Oe eeea. eats 125-26
SpiralenAinvis' seankimnqUayiaici= sachs atonal eryaee oes oie oit cle ciate cle eisai EIS ee ees 136
Stars, aberration of, a means of ascertaining the velocity OfM hte Heese cae ne ete oe ee cee wore ars 122

Stereoscope, principlesof; found,in Galen's Works. <..<-..2<<-10..sacimancmecsitsee vee cemateceeeLeucceeoes 109

238 INDEX.

Page.

Stokes} his discoveriesiinithe spectrum) << .c 2 = ceeciecteemepeieieceet SoS es ses eco e eee oaccer eee 127
Sulphate of lime, effect/of/ heat upon. 22 oa na onan as <aanec ce emeaeeenaaeeeeeeiemes Seco wee 141
Surface Of Clastichtyie eo i5jjaieieelatetepal=i isa = eiaeialm salto aan tale atte esta oe wee ae oie ee seine eae ae 217-18
equation! Of (css P att a-n.n= Soniemtwete esc eRe neeeee eee aennees oe ane ee 217

Circular ReCHONS IN ea oce, aoelocea-sa-eee = see eeeee eee eens ee leet 221

forcry steals OfsOnG | ARIS 2-5. c= 9a ssieae see een eee ae eee ee ee eae ee ee eee 230

Surface, wave, in double refraction; illustrated..: .-- --.<< "Seco sees ee ee nome enae ce oon s- esses 295
G0 UaMON Of: ee eres cea ee me ana ce sec Reece eee eree one see ee eee eee eee ate 225

principal sectionsiof fe c=. 3.52.2 Scns ewe aeeeeme a= eaecian teen see seeaecciciene sce see aes 226

inosculatmnge points Of C=. = ..-<.i.cssccmscwee eee reeset et ener esteem ee cee eee 225-30

Inierystal yO RONGIARIS! a. ccceem—m sae encase Se aes see eaee ee eee eee see eee oe 230

Surfaces, ruled; appearicolored by reflected light....<.stteiedece awe = sees che em eenee see cs ones oe 183
Marirates, TOabOLyapO WCW Ole c1i0ja (= i'=12 arias a1n/arcro alae a fomiaere ee alanis = Sane =e eee eee aes ae = 142
Tension imparts polarizine POW = <= <2..-.cc cle csalnseceeeies Nae te Same te ees ea ee ee eee ae ee ereteen aes 140
MHeories: OFM SM Gee sates aim asinine =\cinia ie sie isynisorie alee mrseinsare see ele ele tae eininia sa ele eee laicia a ea arene te veraiet ee tiatates 143
IMHEOY Of SMISSIOM Ie orale nie e alsio mite i= mm = ataeie wiraie ele eee le meee teesciel le clea a ere eraie ee eee eter aaa 143
Ofna sO 42% Bee cee cis\eien.o deere me cee eerie eee See eee ene ene Sete ciao eter 143, 146
Ofadispersion, by, Cauchy. 22 3o222 25 8s oss eeose sre toe noe Sarinee cecainc saeme eee een 155-56

of reflectionand refraction, by Tuy ehens|.ccromemelerms)\-teate aotearoa eee ee 159

of doublewetraction; by Huyehensso2. <.ccicn Sucre mmee steerer seem esas smite Uae smears 160-61

of polarization in‘refiection,and refraction 3. cci Sec se crmiwe sictee mes oe ace ee else Aaene ree eae 188

MACK plates, (COOLS PLOCUCE OID Yes na cic x= tara reread tee tere ata tlta ae ea atleast eters 120
Thicknesses which produce color in crystalline plates under polarized light. ...-......-...-..-------- 133
‘ in Newton’s rings -..-....- 119

Min plates; Colors produced. Diy. atiase seco ean simi wie sea slain seinem eal ate ene ae a atelene erate 118-20, 183-87
"Dime; Measure Of, IN ViNTaOns --jom alc eiaenia mls a ioebinlejelm ate 'e = el ie tetelne ate alee ane siseins eee ee eas 149
AB Op ai7a ie) ip Gh Cer 5 Se CNN LIN Sa eee me eng mms ce lee lel ae ete te eee oe erties ae eee 139
MorsionimM parts polarize POW ela cme- soe - aimee oes aleve eeiara ola = ete erate aaa als entetey clatter ia 140
Motel reflection; defined. oe). <<< -eiemie= sla er iaerisinie aise msisieeis se See ene nese eerie eae 1838
LimMThiN BN SLO MIN. ccm ace cee Meee ee er ce aciee see eee alesis eect neta ais Semis eet 138

doesnot polarize:commonlichts2. 5. Ssc.siecenaceoanseaseoae ee eee ee sea seteeceessee 138

Tourmaline, its peculiar propertios=. sc j<2= <s~ sec cm ana seers om oie atria cine ee iee eee seme cen eee 132
Trajectories in GinrachonAnterteren CEs. =e ere cna miele 2 eis elec = tet ere eile ee eee eee aris = lee inet 174, 176
Mranspareney Of -P1ass Pes === 2-2 2 oe came cece ace = ReesC ace ee aeeece = eae oe eee eee enemas 131
Transverse vibrations, basis of the theory of polarization .........-...2-.------.-2---.sc0s--.------ -162
IPromorwOeuniiOniOl= ccm. seceeeas==e5s5 Se eae LAS ee Sac he Sie tee ie ene ee ae ome cee ee 152
VOLOCIEY: Of- sic o cemaweceenes sone ne maison maaan se aia = ae ane ninne aera eee 152
howerelated torundalaiion: 5: Sars oseciacems ssc seeisesee eee eee ce aiseme meee stmcmss ssc mes 152
Uys ex COs CV: VSL LSS COPD UNC sek OL ae eters eee ete 139, 227
Wndulatory theory of light - ----..-------- - 2-6-2 nn oo ee as oe ce ie Stee ee seen ee eee nae se aes 143, 146
WnGalation soe 2. scsic cc leis pe aie nla, 2 ate sintavate:s/eia siainiets stots esa oretetaa yale tel ale fate fofe ml aetane te aetete lala tela lote elec ite falereyete 147
how related to vibration --.--.------------ ee eee ee een ee canta teeta 151-53

CURVES 5 ~ <n sini == Hasnain Sine sein snene ce Sie ies mim alarm aia iniere te ee emilee) ey ait as etm ale mam te 153, 146

curves, thein nodal points: - << fcis.a.< le setarm arate rte aie lats eeieraratel ale elatete eleletecatata t= farm etnielajelate eteyeieiteie 198
Undulations unequal for different colors -..--- -.---------- Be te aI ee ee ere ee Roe ee ee 171
eubsolMtevlen obs 10 bapa .c oe ce cee ae mee otra arterial ea eet Seerese 170

TAbletOL = oon cou omcigee eases bee cries le iels siete ee cielo tea ema eee aelerate crete) sols elcteter ere lil

UUM VETS Of pO EP ISC CON Css ns tet ole ie alee ele ela aie eal ee area stare Sods aberon bcs ial

Ot lightand SOUNG COMMPANEC) a.ala pee miscin srommetelele eteyela = alee mettre nena fate eee vale saree erate 17]

ARCOM ORIN Pe sie sce.c ae mie asihisiae Swine aisle apeie ala lelele elmle l= ial inlmta a= miele oi miele i= talaieim eerie im eteraiae 162-64, 166

direction of ‘Vibrations in... - 5.----e.- sees njaisie nan eo sean ne ain lense eee eee nee ens 162, 215

MOSUL GERM ECOL Is SELNGD [DAT Ose ccm reso once myn eles ct ete tr 166

NeSultan MOLI. NOLMAl Planes. saeciec cm iseme me teenies Ma aaa oe ae eee eee materialise teas 168

ViQuid) \< 5 2 naam mais eae cence Hein Soosia's om a cicise ye alsin le ele sicle a s Saeieinte w wieieisice see == 162-63
SONOLOUS.....------------ 22 - ee eee ee ee ee eee eee eee eee eee 15)

in plane polarization ....------------- 22-22-22 2222s foe ern oo es nee eee ee seen eee 215

PTC LL CIT LE LF) O LAM Zieh BL ON cae ates mmm teh mmr em hale ate tetra etetite 1S7

In elliptic Polarization = ~-<1. serait oan wisi iaewivin = swine ls winless em c= ais eimai 198

Unequal velocities of rays of different colors. -.--..-----------++------+---+- +++ 2222-222 22-25 - ee ee 171
Of raysun.doublesiefractlonits=<tans a=. a2= eines eee eae eee ema eee mee 220

Union of two.rayssproducing darkness. 22.12 5-22 --222 55 2550 wees ses seweee soem se ese oe a 114
Varieties:of molecular movements: -25...<.Sccrelale oles cnc siateiare as s'alaisiala's sictaio) alos clmiatalate’nlelrle)alalstetaic=(eleiesinia)s) 157
Varying elasticity of ether in double refracting crystals --...--..------.-------+--------------2-+2-s 162, 216
GHUSES OF S-asSceee eet eeeneee eee eaee esac ee 230

Velocity of light... 2.02 s00c242522 celeesie ns ccieise scien cee vin ecle a enicisiec cn scene eseainsesesesensccenees 121,125
GE BOUNG:,-C wcieeiscis Saree arcsare ere cm reere et rer ataaiw entarianseneiictets Rcle ai eee ee aan eee se Socnhs 153-55

of sonorous mndulations) UnitOrmesas aoasccs< ase cinisise emer ee sae eee ae eet aaa cial 155

of rays of different colors, unequal). stis15 is ia lastalane Ha sfehcinn oie ere memati sinless 155

of rays. in double refraction, unequal... .----.2.- 262.02 -262-2 2-25-52 c eee eee ee ee eae eee 220

of tremors amielastic Muids! 5s. orsearstaretara tans nici tw crnloinvaine stain ae = alate ole a)a eee ate ceteris 152

of molecular movements in WaVES~-2..--'--2--- -siesse eee ne een ee seme cconns cee enn 157

RUA PO SUEL OL ve oc omc, wes ssc SPMD ath peered (eerste mre eal mT ate Sat fattest ttn =p oh eter ete = atte ea 147-51
Vibration, how converteduntorevOlutlOnioss2<c canon cise seats. eta a lalele ie re ete el isneet = 148
, how related to undulation... 1252 <2 scs-isse- - esos foal oc ecceoe cece ese same seo 151-53

MME ASULG OF, GME Ivers njaecelercrsn are aeratatate tate eet atat- te atoll otalala et a\e lala = ey = fatata talaretatate ele alata ota a acayal 149

OF Velocity im. 2 Jcmrsiecicnieercttiafars winlalololocles ele islele ole sie = == rele ate aa ara hale otal ete pet etelereceta lela iavatera 147
Vibrations, how compounded....-.-..------------+-- 2-22 2--- 220 eee eee eee eee eee eee eee eee eee 48=5or
transverse, the basis of Meesnelisithe omy amet mate arin =r ele Sita ee erate le aie otala- era 162, 215

relative, of the rays produced by double refraction --......-..-.------------------------ 162, 220

of common'light. indeterminate imazimuth eso 3. sae a nee eemiaeinles esa cesaclce 165

OF EES ye Mua Mea stealer spear re rai te tn whe te ler fe tata aS a ede plats ele tl tdi © wll) 2 miele erate 148

TSO COMONISHY OL je fats = atari tasers apts Ie T nate aw a ett nfl sedate 147
Wavelsurface, illustrated ..-..--.--.----------- 2-222 - ee nn eee eee ee eee nee eee eee ee eee eee ee 225
EQUATION OL: oo. Sina erecta arate S wie ewl a alee tmlelniwiminin s/n alam (aim ielm alat=tetalsfetcininin aleiel= = =insis/misiae isin 225

* principal sections Of ~ -=---..2- 2222-20 esses n-ne ne ene eee ennscin seen een nee ssens-- 226

of crystals of one axis-----------..--- aaa aia ela a alee eae ala) = eee era 230

Wave-progress and ray-progress distinguished......-..--.----.------------+ 2-22-22 eee eee ee eee 224

INDEX. 239

Page.

Wiavervelocitiesvof light, unequal! : Meer sas ate cide mes 2 nine sresfea cee s eid sid ens seicbicieciels wacieieccc ee 155
Wiayenvelociticsiomsound,, equal’. |< 4 ne tetris alse Sos ccc oe natok aac Anam cece deme euain inet 153
BVVEnVC Sey 10) Clpeteetene petite tate are clam mamta clare niente ee neta aie nolo siniald ace ctorci= = cia sate aioe saeco eine nels 162-63
VALICUES On MOleCH Ar MOVeMeNtils oes ceaie semen e ae ele om Sa cicislaln ees eaje pies cams seicesis eats J57
ofcondensationsand rarefaction; denned scece secs ccc emace ccecccckcececocseceasucoucescece 153
unequal in length for different colors.....-..-- 17]
resultant of, in same plane 166
resultantiof, in normal planes? Jaci) acto cys cicisisis c= sisi ce siete ais\siele vain ns siajucinwe.ceaie.ccne slaciane 168
interienine;; mushhayeryCOMMOn ON PIN -\-.5- ons ceeceee elise eee e seceecienesece sarceoaesses 168
ofslightiand: sound, compared) mss es scmcererarie a Go tte lel ne Jo Sasiaieecinninwiaiciasacieciee sscesaiae sic 171

plane, considered as resultant of elementary spherical waves. .------.-.---.---------------- 15)
Wiheatstonemnisipolartclock: ose. sce maser mee acts ase eae es ae oie ome wa ae es csc ecmeaae oe 143
WiollastonAhisidiscovery of fixeddJines inithespectrum: o<- << 27-m= je ane nasoes case seece oe nalelece nce 125-26
Young, hypothesis of transverse vibrations suggested by ....-.-.-----eaee--ececcecnceccencceesecees 162

ERRATA.

Page 110, line 5 from bottom, for =e aintg read Vei—sing’

Page 112, line 16 from bottom, for mth read (#-+-1)st, in both instances.

LECTURES.

PHYSICAL ETHNOLOGY.

By DANIEL WEESON, aD;

PROFESSOR OF HISTORY AND ENGLISH LITERATURE IN UNIVERSITY COLLEGE, TORONTO,
UPPER CANADA.

PART fi.

THE AMERICAN CRANIAL TYPE.

Among the novel questions to which the progress of science has given promi-
nence, under aspects undreamt of in very recent years, is that of the relation
of man to the inferior orders of being, and his true place in nature as one of the
animal creation. In this respect, the investigations of the craniologist, and the
whole bearings of physical ethnology, are now acquiring an mterest and import-
ance very partially accorded to them before. The geologist, who long ignored
all that related to man and his works, as recent, and therefore without the pale
of his comprehensive researches, now recognizes both his remains and his works
of art as pertaining to the department of paleontology; and disputes with the
archeologist the appropriation of the primitive flint-implements of the drift, once
claimed exclusively by him for his Age of Stone. This has materially affected
the aspects of the study of physical ethnology ; for until very recently the dif-
ferences between man and all other animals have been assumed to be so clearly
defined, that the naturalist was long induced to overlook those which distinguish
different races of men, and to regard any diversities of structure or relative pro-
portions in the human form as mere variations from one common or ideal type.
Nevertheless the craniologist, at the very commencement of his investigations,
is led to recognize certain essential varieties of form; though still tempted, Itke
Blumenbach, to refer all these to some “Caucasian” or other assumed highest
type. Before, however, the ethnologist directed his attention to such researches,
the artist had sought this type in the beautiful realizations of Greek sculpture ;
and by such means he determined the long-accepted statuary scale of the human
head and figure. Nor ean the influence of this artistic ideal be overlooked in
the direction it gave to some of the speculations of the craniologist, and to the
theoretical conception of the fully-developed man. It guided Camper in assign-
ing the laws of his facial angle; controlled Blumenbach in his determination of
the cranial peculiarities of leading races of men; and even influenced Prichard
in his definition of the symmetrical or oval form of skull which he ascribed to
his first division. Against the ideal canons of an antique statuary scale, how-
ever, some of the greatest modern masters protested ; foremost of whom was
Leonardo da Vinci, of whom Bossi remarks, “He thought but little of any
ecneral measure of the species. The true proportion admitted by him, and
acknowledged to be of difficult investigation, is solely the proportion of an indi-
vidual in regard to himself, which, according to true imitation, should be diter-
ent in all the individuals of a species, as isthe casein nature.” In the features

PHYSICAL ETHNOLOGY. DAT

of the face there are the endless varieties of portraiture, controlled by family
and national affinities, and so also in the varying proportions of the skull there
appears to be an approximation in each race towards a special form. The cra-
niologist accordingly finds in nature his brachycephalic or short skull; his
dolichocephalic or long skull; his kumbecephalic or elongated (boat-shaped)
skull; his pyramidal or acrocephalic; his platyeephalic or flattened; his trun-
eated, oval, and spherical skulls ; as well as many intermediate forms. An idea,
however, has long prevailed with reference to the aborigines of the New World, the
origin of which is traceable to this distinguished American craniologist, Dr.
Morton, that throughout the vast continent, from the arctic cirele to the icy
shores of Terra del Fuego, the Esquimaux constitutes the one exception to a
predominant uniform cranial type.

The opinions advanced by one so distinguished and indefatigable in his study
of the science as the author of the Crania Americana well merited the atten-
tion they have received, and might even seem to justify the assumption of
them as indisputable scientific canons. Only one other authority could have
earried any corresponding weight, and that is produced to confirm the conelu-
sion referred to. “The nations of America,” says Humboldt, “except those
which border on the polar circle, form a single race, characterized by the forma-
tion of the skull, the color of the skin, the extreme thinness of the beard, and

‘straight glossy hair.”

Very few and partial exceptions can be quoted to the general unanimity of
American writers—some of them justly regarded as authorities in ethnology—
in reference to this view of the nations of the whole American continent, north
and south, as one nearly homogeneous race, varying within very narrow limits
from the prevailing type, and agreeing in so many essentially distinctive features,
as to prove them a well-defined variety, if not a distinct species, of the genus
Homo. Lawrence, Wiseman, Agassiz, Squier, Gliddon, Nott and Meigs, might
each be referred to in confirmation of this opinion, and especially of the prevail-
ing uniformity of certain strongly-marked cranial characteristics ; but in reality
the most of them only echo the opinions of Dr. Morton, and reproduce conclusions
which his laboriously-aceumulated evidence was supposed to have established
beyond dispute. His views underwent considerable modification on some points
relating to the singular cranial conformation observable in certain skulls found
in ancient American graves; especially in reference to the influence of artificial
means in perpetuating changes of form essentially different from the normal
type; but the tendencies of his matured opinions all went to confirm his original
idea of universal approximation to one cranial type throughout the New World.
In his final contribution to his favorite science, on “'The Physical Type of the
American Indians,”’* his matured conclusions relative to the cranial type of the
American continent are thus defined: “The Indian skull is of a decidedly
rounded form. The occipital portion is flattened in the upward direction, and
the transverse diameter, as measured between the parietal bones, is remarkably
wide, and often exceeds the longitudinal line.t_ The forehead is low and reced-
ing, and rarely arched, as in the other races ; a feature that is regarded by Hum-
boldt, Lund, and other naturalists, as a characteristic of the American race, and
serving to distinguish it from the Mongolian. The cheek-bones are high, but
not much expanded; the maxillary region is salient and ponderous, with teeth
of a corresponding size, and singularly free from decay. The orbits are large
and squared, the nasal orifice wide, and the bones that protect it arched and
expanded. The lower jaw is massive and wide between the condyles ; but not-

* Schoolcraft’s History of Indians, vol. TI, p. 316.

+ No such excess of the parietal over the longitudinal diameter is ever found except in a
greatly distorted flathead or other artificially detormed skull; and of this only one exarple
occurs in the Crania Americana,

16s

242 PHYSICAL ETHNOLOGY.

withstanding the prominent position of the face, the teeth are for the most part
vertical.”

The views thus set forth, on such high authority, have exercised an important
influence on all subsequent investigations ; of which, perhaps, no instance is
more illustrative than that of Stephens, who submitted to Dr. Morton the broken
fragments of a skull rescued by him from an ancient grave in the rus of Ticul;
and though the observant traveller had already noted essential differences of
ethnical characteristics between the physiognomies and head-forms sculptured
on the ruins of Central America and those of the living race of Indians, he
appears to have implicitly resigned his judgment to the homogeneous theory of
Dr. Morton, and reproduces his opinion of the skull as that of a female, pre-
senting ‘‘the same physical conformation which has been bestowed with amazing
uniformity upon all the tribes on the continent, from Canada to Patagonia, and
from the Atlantic to the Pacific ocean.’’*

Tis supposed prevalence of a remarkable uniformity of cranial conformation
throughout tribes occupying forest, prairie, mountain plateau, or oceanic archi-

elago, and ranging from the arctic circle through every degree of latitude
almost to the antarctic circle, being assumed as an established truth, has furnished
the basis for further deductions of an equally comprehensive kind. Professor
Agassiz, in discussing the provinces of the animal world and their relation to
the different types of man, points out certain physical features of the western
hemisphere which tend to adapt it for a much more uniform distribution of
fauna than the European, Asiatic, and African regions present in corresponding
latitudes. “'The range of mountains which extends in almost unbroken con-
tinuity from the Arctic to Cape Horn, establishes a similarity between North
and South America which may be traced also to a great degree in its plants and
animals. Entire families which are peculiar to this continent have their repre-
sentatives in North as well as South America—the cactus and didelphis, for
instance ; some species, as the puma or American lion, may even be traced from
Canada to Patagonia. ‘Thus, with due qualification, it may be said that the
whole continent of America, when compared with the corresponding twin conti-
nents of Europe—Africa or Asia—Australia is characterized by a much greater
uniformity of its natural productions, combined with a special localization of
many of its subordinate types. With these facts before us, we may expeet that
there should be no great diversity among the tribes of man inhabiting this con-
tinent ; and, indeed, the most extensive investigation of their peculiarities has
led Dr. Morton to consider them as constituting but a single race, from the
confines of the Esquimaux down to the southernmost extremity of the conti-
nent.”t That the elements of diversity dependent on physical geography and
the consequent influences of climate on food, temperature, &c., by which the
distribution of the fauna of every region is controlled, are much less varied
throughout the American continent than elsewhere is indisputable. But the
effects of this comparative uniformity, or rather smaller range of diversity of
climate and physical influences, in so far as they control the distribution of
plants and animals, differ essentially from the operation of the same causes in
producing an apparent uniformity among the tribes of men inhabiting the same
continent. J*in, Celt, German, Sclave, Magyar, and Turk, all present as great
a superficial resemblance as the diverse tribes and nations of the New World,
where they have been long subjected to the same equalizing influences of climate,
social intercourse, and intermingling of blood. But the ethnologist still finds
the osteological indices of diversity of race unobliterated ; and the results of
the investigations set forth here have sufficed to satisfy me that the same diversity
is still traceable among the ancient and living tribes and nations of this continent.

Set cere = _ —--

* Stephens’s Yucatan, vol. L., p. 284
7 Provinces of the Animal World, &. Types of Mankind, p. Ixix.

PHYSICAL ETHNOLOGY. 243

Whilst, however, the supposed unity in physical form asserted by Dr. Morton,
and accepted as an established scientific truth in relation to the races of man in
the New World, has been reiterated on many occasions, its originator was not
unaware that it was, at most, only an approximation to his assumed type, and
was subject to variations of a very marked kind; although he did not allow their
just weight to these when determining the conclusions which seemed legitimately
to result from his carefully accumulated data. He thus remarks, in his Crania
Americana, on certain unmistakable diversities of form into which the assumed
American cranial type may be subdivided, when classing the so-called barbarous
nations: “ After examining a great number of skulls, I find that the nations
east of the Alleghany mountains, together with the cognate tribes, have the
head more clongated than any other Americans. ‘This remark applies especially
to the great Lenapé stock, the Iroquois, and the Cherokees. 'To the west of the
Mssissippi we again meet with the elongated head in the Mandans, Ricaras,
Assinaboins, and some other tribes.”’* The Minetaries, Crows, Blackfeet, and
Ottoes are named along with those in his latest reference to the subject, thereby
transferring the Ottoes from the brachycephalic to the dolichocephalic class, in
which he had previously placed them; for, to his earlier statement, Dr. Morton
superadds the further remark: “ Yet even in these instances the characteristic
truncature of the occiput is more or less obvious, while many nations east of the
Rocky mountains have the rounded head so characteristic of the race, as the
Osages, Ottoes, Missouris, Dacotas, and numerous others. The same conforma-
tion is common in Florida; but some of these nations are evidently of the
‘Yoltecan family, as both their characteristics and traditions testify. The heads
of the Caribs, as well of the Antilles as of terra firma, are also naturally
rounded ; and we trace this character, as far as we have had opportunity for
examination, through the nations cast of the Andes, the Patagonians, and the
tribes of Chili. In fact, the flatness of the occipital portion of the cranium will
probably be found to characterize a greater or less number of individuals in
every existing tribe from Terra del Fuego to the Canadas. If their skulls be
viewed from behind, we observe the occipital outline to be moderately curved
outward, wide at the occipital protuberances, and full from those points to the
opening of the ear. From the parietal protuberances there is a slightly curved
slope to the vertex, producing a conical or rather a wedge-shaped outline.”
These opinions are still more strongly advanced in Dr. Morton’s most matured
views, where he affirms the American race to be essentially separate and peculiar,
and with no obvious links, such as he could discern, between them and the
people of the Old World, but a race distinct from all others.

Some of the uniform features above referred to, and especially the flattened
occiput, are the product, as I believe, not of the approximation to any typical
form of skull, but of the subjection of the living head to the same artificial
compression, with a nearly uniform result. But this department of the subject
will come under review at a later stage. The views now set forth relative to the
American cranial type are founded on an extensive series of observations orig-
inally commenced in Canada, without any design to challenge the opinions set
forth by the author of the Crania Americana, and subsequently reiterated by
other distinguished American ethnologists. After having devoted minute atten-
tion to some departments of primitive British craniology, my removal to Canada
placed within my reach opportunities of judging for myself of the physical
characteristics of the aboriginal occupants of the American forests and prairies,
and I availed myself at first of those in the full anticipation of meeting with
such evidences of a general approximation to the assigned normal American
cranial type, as would confirm the deductions of previous observers. My chief

= Crania Americana, p. 65; Physical Type of the American Indians; History of Irdina
Tribes, vol. ii, p. 317.

244 PHYSICAL ETHNOLOGY.

aim, indeed, originally was to acquire specimens of skulls approximating to the
peculiar brachycephalic type found in one important class of early British
graves. It was, accordingly, simply with a sense of disappointment, that I
observed the results of repeated explorations in different cemeteries furnish
crania which, though undoubtedly Indian, exhibited little or no traces of the
rounded form with short longitudinal diameter, strikingly apparent in certain
ancient Mexican and Peruvian skulls, as well as in the rare examples hitherto
recovered from the mounds of the Mississippi valley. Slowly, however, the
conviction forced itself upon me that to whatever extent this assigned typical
skull may be found in other parts of the continent, those most frequently met
with along the north shores of the great lakes are deficient in some of its most
essential elements. Similar conclusions have been recorded by different observers.
They are indicated by Dr. Latham, when comparing the Esquimaux and
American Indian forms of skull, as determined by Dr. Morton ;* and have since
been strongly affirmed by Dr. Retzius, who states that it is scarcely possible to
find a more distinct separation into dolichocephalic and brachycephalic races
than in America;t nor should the remark of Professor Agassiz be overlooked,
when, after referring to Dr. Morton’s single American race, he adds: ‘“ But it
should be remembered that in accordance with the zoological character of the
whole realm, this race is divided into an infinite number of small tribes, pre-
senting more or less difference one from another.’ It is indeed necessary to
determine what must be regarded as the essential requisites-of Dr. Morton’s
American typical cranium; for neither he nor his successors have overlooked
the fact of some deviation from this supposed normal type, not only occurring
occasionally, but existing as a permanent characteristic of some tribes. As has
been already shown, Dr. Morton recognized a more elongated head: as pertaining
to certain of the northern tribes, but this he speaks of as a mere slight variation
from the more perfect form of the normal skull; and he adds: “ Even in these
instances the characteristic truncation of the occiput is more or less obvious.’’t
So also Dr. Nott, after defining the typical characteristics of the American
cranium, remarks: “ Such are more universal in the Toltecan than the barbarous
tribes. Among the Iroqaois, for instance, the heads were often of. a somewhat
more elongated form; but the Cherokees and Choctaws, who, of all barbarous
tribes, display greater aptitude for civilization, present the genuine type ina
remarkable degree. My birth and long residence in southern States have per-
mitted the study of many of these living tribes, and they exhibit this conformation
almost without exception. I have also scrutinized many Mexicans, besides
Catawbas of South Carolina, and tribes on the Canada lakes, and can bear
witness that the living tribes everywhere confirm Morton’s type.’’§

In selecting a skull, which seemed to Dr. Morton in all respects to fulfil the
theoretical requirements of his typical cranium, we are guided, under his direc-
tions, to that ancient people who, in centuries long prior to the advent of EKuro-
peans, originated some remarkable traits of a native civilization in the valleys
of the eastern tributaries of the Mississippi. It will, therefore, coincide with
his choice of an example of the true American head, if, starting from that
ancient race, we pursue our comparisons downward to the nations and tribes
* familiar to Europeans by direct intercourse and personal observation.

Among the most prized crania in the collection of the Academy of Natural
Sciences at Philadelphia is the celebrated Scioto mound skull, familiarly known
to many by means of the views of it introduced among the illustrations of

== Natural History of the Varieties of Man, p. 453.

+ Arch des Sciences Naturelles, Geneva, 1360. The views set forth here were first pub-
lished by the author at the meeting of the American Association for the Advancement of
Science, in 1857. Vide Edin. Philosoph. Journal N. S§., vol. vii.

t{Crania Americana, p. 69; History of Indian Tribes, vol. ii, p. 317.

§ Types of Mankind, p. 441.

PHYSICAL ETHNOLOGY. — 245

Messrs. Squier and Davis’s “Ancient Monuments of the Mississippi Valley.”
A careful examination of the original, however, brings out features of this
remarkable skull, by no means apparent in the engravings. The vertical view,
especially, is inaccurate. In the original it presents the peculiar character-
istics of what I have before designated the truncated form: passing abruptly
from a broad flattened occiput to its extreme parietal breadth, and then taper-
ing, with slight lateral swell, until it reaches its least breadth, immediately
behind the external angular processes of the frontal bone. The occiput has been
subjected to the flattening process to a much greater extent than is apparent
from the drawings; but at the same time it is accompanied by no corresponding
affection of the frontal bone, such as inevitably results from the procedure of the
Chinooks and other Flathead tribes; among whom the desired cranial deforma-
tion is effected by bandages crossing the forehead and consequently modifying
the frontal as much as the parietal and occipital bones. On this account, great
as is the amount of flattening in this remarkable skull, it is probably due solely
to the undesigned pressure of the cradle-board acting on a head of markedly
brachycephalic proportions and great natural posterior breadth. The forehead
is fully arched, the glabella prominent, and the whole character of the frontal
bone-is essentially different from the Indian type. The sutures are very much
ossified, and even to some extent obliterated.

The “ Scioto mound cranium,” the best authenticated and most characteristic

Fig. 1. Fig. 2.

of the crania of the mound-builders, when discovered, lay embedded in a com-
pact mass of carbonaceous matter, intermingled with a few detached bones of
the skeleton and some fresh-water shells. Over this had been heaped a mound
of rough stones, on the top of which, incovered by the outer layer of clay, lay
a large plate of mica, that favourite material of the ancient mound-builders.
This is the skull which, according to the description of Dr. Morton, furnishes the
best example of the true typical American head. It is produced as such by
Dr. Nott, in the Types of Mankind, and, as described by Dr. Morton, ‘‘it is, per- ,
haps, the most admirably formed head of the American race hitherto discovered.

It possesses the national characteristics in perfection, as seen in the elevated

»

246 PHYSICAL ETHNOLOGY.

vertex, flattened occiput, great interparietal diameter, ponderous bony structure,
salient nose, large jaws and broad face. It is the perfect type of Indian con-
formation, to which the skulls of all the tribes from Cape Horn to Canada more
or less approximate.”

Of this skull the measurements which involve the most essential typical
elements, and so furnish precise materials for comparison, are—

Loneitudimaldimameter .. --.- joensen = = Ss a ee 6.5 inches.
IPANICUoeMaINELGr™ oe. o.oo Lime one care cee etter 6. ‘6
Weruicawalameret. . . oa. atlc eam ue ok omer eee Gre ace
liiber-ImashmiU are. ic) 2 5c ancjenn ea rete tebe 6 Seen 16. ee
Horizontal circumference ........... rere als eee oe TOLO" nee

So that, in fact, the cranium very closely corresponds in its measurements, in
length, breadth, and height. Still further, it may be noted that the singular
longitudinal abbreviation of this skull is nearly all posteriorly. A line drawn
through the auditory foramen in profile, parallel to the elevated forehead, divides
it into two unequal parts, of which the anterior and posterior parts are nearly
in the ratio of three to two. If, however, we turn from the definition of the
American typical form, as recorded in relation to this particular skull, and reduce
it to the general formule derived by its originator from the examination of
numerous examples, it amounts to this: A small receding forehead, somewhat
broad at the base, but with a greatly depressed frontal bone; a flattened or
nearly vertical occiput; viewed from behind, an occipital outline which curves
moderately outwards, wide at the occipital protuberances, and full from these
points to the opening of ‘the ear; from the parietal protuberances a slightly
curved slope to the vertex, producing a wedge-shaped outline; a great vertical
diameter, and the predominant relative .interparietal diameter of the brachy-
cephalic cranium. If to those are added the large quadrangular orbits, the
cheek-bones high and massive, the maxillary region salient and ponderous, and
the nose prominent, we have, nearly in Dr. Morton’s own words, the character-
isaic features of that American cranium which prevails among both ancient
and modern tribes of the brachycephalic type, and has been assumed by him as
universal.

It is with great diffidence that I venture to challenge conclusions adopted
after mature consideration by the distinguished author of the Crania Americana.
The frontal bone of the Scioto mound skull is by no means depressed, but well
arched, and the flattened occiput bears unmistakable evidence of an artificial
origin. ‘The conical or wedge-shaped vertex of the Indian head is very par-
tiaky traceable in the original, even when viewed from behind, and, altogether,
when tried by Morton’s own standard, it differs greatly from the American typi-
cal cranium. ‘lhe same skull has been selected, by Dr. J. C. Nott,* for the
purpose of instituting a comparison with the well developed and characteristic
head of a modern Indian, a Cherokee chief, who died while a prisoner at
Mobile in 1837, and the two crania are there engraved side by side, with other
examples, “to show, through faithful copies, that the type attributed to the
American races is found among tribes the most scattered; among the semi-civi-
lized and the barbarous; among living as well as among extinct races ; and that
no foreign race has intruded itself into their midst, even in the smallest appre-
ciable degree.”’t. But, judging merely by the reduced profile drawings, placed
in juxtaposition, without reference to precise measurements, the points of agree.

* Types of Mankind, p. 442.

t Dr. Nott’s definition is as follows: ‘*The most striking anatomical characters of the
American crania are, small size; low, receding forehead; short antero-posterior diameter;
great inter-parietal diameter; flattened occiput; prominent vertex; high cheek-bones; pon-
derous and somewhat prominent jaws.”— Types of Mankind, p. 441.

’

PHYSICAL ETHNOLOGY. 247

ment are very partial. 'Uhe vertical occiput of the ancient skull rounds some-
what abruptly into a flat horizontal vertex, and with the well developed fore-
head and short longitudinal diameter, gives a peculiar square form to it in pro-
file. In the modern skull, on the contrary, the occipital flattening is not so much
that of the occiput proper as of the posterior part of the parietal, together with
the upper angle of the occipital bone; thereby uniting with the receding fore-
head of the latter, to produce a conoid outline, in striking contrast to the square
form of the other. Still further, a vertical line drawn through the auditory fora-
men shows a remarkable preponderance of posterior cerebral development in the
ancient skull, constituting indeed its most striking peculiarity. But a compar-
ison of the measurements of the two skulls serves no less effectually to refute
. the supposed correspondence adduced in proof of a typical unity traceable
- throughout tribes and nations of the western hemisphere the most widely sepa-

rated alike by time and space.
Ancient. Modern.

lteveituamaltdiamerers’: £270 Serer 26d 2S es 6.5 6.9
IAT OLAS eee ata Seas REAGENT TAEL M ENS OS He 6.0 aah
RUFC TTC EU AR aeeR REPEL ER NT EG Sh ESE SIS GRA A 6.2 5.4
PEROT LLeA D, eETS SPSL ENy 8 OO 4.5 4.6
Hiitermastord sirch: Yee iese Ske) eT ee oF 16.0 15.5
fintersmastordeline{.la2 eee eRe ae oe 4.5 4.75
Ocemiio-frontalvatich. 2252 2272. ee ET! 13.8 14.4
Horizontal’ cireumterence’s oJ) 0000555... 0024 19.8 O(a 5

It is not to be supposed that any single skull can be selected as the embodi-
ment of all the essential typical characteristics either of the ancient or the mod-
ern cranial conformation; nor can we deduce general conclusions as to the physi
eal characteristics of the ancient mound-builders from the remarkable example
above referred to. We lack, indeed, sufficient data as yet for any absolute deter-
mination of the cranial type of the mounds; but the Scioto mound skull cannoi
with propricty be designated as “the only skull incontestably belonging to an
individual of that race.” The Grave creek Mound cranium, figured by Dr.
Morton, belongs no less indisputably to the same race, and presents in its arched
forehead, prominent superciliary ridges, and compact, uniformly rounded profile,
a general correspondence to the previous example.* In 1853 Dr. J. C. Warren
exhibited to the Boston Natural History Society the cast of a second and more
perfect skull from the same mound,t which I have since examined and measured
in the collection of Dr. J. Mason Warren. It is also worthy of note that sev-
eral inferior maxillary bones of the mound skeletons have been recovered nearly
entire. They are remarkable for their massiveness, but are described as less
projecting than those pertaining to the skeletons of a later date.{ Another
skull figured by Dr. Morton, from a mound on the Upper Mississippi, was obtained
from an elevated site bearing considerable resemblance to that where the Scioto
valley cranium was found, but the evidence is insuflicient to remove the doubts
which its proportions suggest, that in this, as in so many other cases, we have
only one of those later interments habitually made by the modern Indians in
the superficial soil of the mounds. It is better, meanwhile, to reject all doubtful
specimens than to incur the risk of cumbering such well-authenticated evidence
as we may: anticipate with uncertainty and confusion. The following table
includes a series of measurements of mound and ancient cave crania, mostly
taken by myself from the originals in the collection of the Academy of Natural
Sciences at’ Philadelphia and elsewhere:

* Crania Americana, pl. liii, p. 223.
t Proceedings of Boston Natural History Society, vol. iv, p, 331.
t Ancient Monuments of the Mississippi Valley, p. 290.

248 PHYSICAL ETHNOLOGY.

TABLE I.—MOUND AND CAVE CRANIA.

| Locality. ip D. LP. D. | Fe De | Vere: 0. Av eT. 14] O. Bea. erence

1 | Scioto Mound......... 6.5 6.0 4.5 6.2 16.0 | 4.5 18 19.8
2 | Grave Creek Mound...) 6.62 | 6.0 |..---. Sr Oaileestees oie ae $4027 is eee oe
Se OM sAb eae ee 6.6 6.0 4.0 5.4 15.6 Ar Bewileat. wh4: 20.2
4 Tennessee Mound--.-- 6.6 5.6 4.1 5.6 15.2 4.4 14.0 19.5
5 | Huron,River, Ohio....| 6.7 5.7 AS OP Meer ar | 14.8 4.4 14.2 19.8
GRA: 2: do. bbe: (Hem.)-| 6.7 5.4 4.0 5.4 14.0 4.2 Si 19.9
7 | Ohio Mound.. (Hem.).| 6.4 5.3 | 4.0. | 5.0 DASB Ds ide IANVIE aah 19.0
8 | Alabama Mound..-.--.- | 6.2 5.4 4.3 4.9 14.6 3.8 13.3 18.5
9 | Golconda Cave -.------ | 6.7 5.4 4.3 Bs 14.5 4.1 14.0 19.3
10 | Steubenville Cave. -.--- 7.0 6.1 4.6 5.6 15.5 4.3 14.0 30.5
Lavy eee dosnt. ask 2th | 6.8 5.9 4.4 NT 15.5 4.5 14.4 20.5
1 Oi ed OR Nepae haeees awsce 6.3 5.9 4.9 ee 15.8 5.0 14.1 20.0
Tees |e perce iss 8 reer cry ye: 6.6 6.0 4.6 al 14.6 4.2 one 20.0
1luk cea Sse eee Salas ae EY S| O20 5.4 4.3 ail 14.2 4.3 13.9 19.0
TS MIee slot 222 oro SE ee aU, 5.8 4.5 SD 14.9 4.5 14.4 20.3
HG erdoss. = Jibs see 6.7 6.0 4.5 BYE 15.4 4.7 14.1 20.3
EO O)43\23-5 « Serte Ry 3|\ 622 6.1 4.5 4.9 15.2 4,1 13.3 19.4
TC rc Fc ee Gal ond 4.6 5.0 15.0 4.4 14.2 20.2
OW ee dO roma sete aes 6.2 6.0 4.5 Eye 14.8 4.0 13.2 19.4
20 | Kentucky Cave...--.-- Gof SrA PATA 516 14.5 | 4.4 13.6 18.4
ila aere dose seat. Sse 6.7 525 4.5 6.2 13.5 DION ta oa, | 19.7
Mound Crania mean-.-.| 6.54 | 5.67 | 4.13 | 5.36 | 14.91 | 4.23 13.83 | 19.53
Cave Crania mean....| 6.62'| 5.78 | 4.51 | 5.47 || 14.85-| 4:42 13.87 | 19.77

|

Total mean=.-~ + --- 6.58) | 15:74) 4537 | 5.43 14.87 | 4.35 13.86 | 19.68
! ¥

Of the series embraced in this table, though all are ancient, only the first four
can be reked upon as undoubted examples of the crania of the mounds. In
comparing them with others, there are indications of a peculiar cranial type par-
tially approximating to the brachycephalie Peruvian cranium; but this assumed
correspondence has been exaggerated, and some important differences have been
slighted or ignored in the zeal to establish the aflinities which such an agree-
ment would seem to imply. In vertical elevation the Peruvian cranium is
decidedly inferior; and another point of distinction, borne out, by the few well-
authenticated mound crania, is the well-formed and arched frontal bone, unaf-
fected by the pressure to which the flattened occiput must be in part ascribed,
and accompanied by great prominence of the superciliary ridges. ‘These differ-
ences were overlooked by Dr. J. C. Warren, who pronounced the Mound and -
Peruvian crania to be identical. A greater correspondence seems to me to be
traceable between the most ancient crania of the Mexican valley and those of
the mounds. But, tempting as are the conclusions which such analogies sug-
gest, any final decision on the subject must be reserved until further discoveries
place within our reach a sufficient number of skulls of the ancient Mound-
builders as well authenticated as those of the Scioto valley afd Grave creek
mounds. ‘This there is little hope of achieving, until a systematic exploration
is instituted under the direction of a carefully constituted scientific commission,
the organization of which would reflect credit on the government of the United
States. The Cave crania, Nos. 9-21, are a remarkable series of* undoubted
antiquity, and present a nearer approximation to those of the Mounds than any
other class. ‘Vheir most notable divergence from the mound type, in the parietal
diameter, disappears if the doubtful examples of the latter, Nos. 5-8, are ex-
cluded, as in ‘lable X.

PHYSICAL ETHNOLOGY. 249

Turning from this review of the meagre data hitherto recovered from the
ancient sepulchral mounds, let us next consider the two great civilized nations
of the New World, the Peruvians and Mexicans. Their civilization had an
independent origin and growth. The scenes of its development were distinct;
and each exhibited special characteristics of intellectual progress. Nevertheless,
they had so much in common, that the determination of the physical type
peculiar to each will be best secured by ascertaining what is common to both.

When Dr. Morton first undertook the investigation of the cranial character-
istics of the American races, he admitted the force of the evidence presented
to him in the examination of a number of ancient Peruvian skulls, and has
recorded in his Cranza Americana a distinct recognition of the traces of well-
defined brachycephalic and dolichocephalic races among the ancient Peruvians.*
But the seductive charms of his comprehensive theory of an American cthnie
unity ultimately prevailed over the earlier opinion, which, even in the Crania
Americana, was stated as the legitimate deduction from the evidence in ques-
tion, without being incorporated into the author’s concluding propositions; and
he accordingly states his conviction that all the extremest varicties of the Peru-
vian head were naturally of the same rounded shape, and owe their diversities
of forin to artificial deformation. In this, as in others of the deductions drawn
by Dr. Morton from the carefully accumulated data which his well-directed
industry contributed to the science, it is obvious that his mind dwelt too exclu-
sively on one or two of the leading characteristics of the more numerous varie-
ties of American crania; and, like others who have satistied their minds in regard
to one central type, he evaded every variation from it, by assuming it as a mere
exceptional aberration.

A revision of the evidence accumulated by Dr. Morton, along with additional
illustrations derived from other sources, suggests conclusions in reference to
Peruvian cranial forms at variance with the idea of a universally prevalent
rounded, or brachyeephalic Peruvian head. In pursuing my researches on this
subject, I have enjoyed the advantage of minutely studying and measuring an
interesting collection of crania and mummied bodies, brought by John H. Blake,
esq., of Boston, from ancient Peruvian cemeteries on the shores of the Bay
of Chacota, in latitude 18° 30'S. In addition to those the following tables of
Peruvian crania include measurements made from others, in the collections of
Dr. J. M. Warren and the Natural History Society of Boston; in that of the
Academy of Natural Sciences of Philadelphia, and of the Smithsonian Institution,
Washington. ‘The materials upon which Dr. Morton based his final opinion
that the dolichocephalic crania found in ancient Peruvian graves derive their
form and proportions from artificial causes, and consequently that these have
no ethnical significance, are still accessible; and the bearings of the additional
evidence since accumulated justify a reconsideration of the proets. Since the
subject was taken up by him the effects, not cnly of designed, but also of unde-
signed artificial compression, and of posthumous distortion, on cranial forms,
have been minutely studied. The application of continuous pressure on the
skull during infancy can be carried so far as to obliterate nearly every trace of
its normal proportions. But it cannot substitute for them a symmetrical artifi-
cial conformation. [ven comparatively slight pressure is betrayed by a corre-
sponding amount of inequality in the opposite sides of the head; and when the
compression is such as would be required to convert a brachycephalic head,
averaging 6.3.in longitudinal diameter, by 5.3 in parietal diameter, into a dolicho-
cephalic head. of 7.3 by 4.9 in diameter, the retention of anything like the
normal symmetry is impossible. The following table of measurements illus-
trates the proportions of the Peruvian brachycephalic skull:

* Crania Americana, p. 98.

250 PHYSICAL ETHNOLOGY.

TABLE I1.—PERUVIAN BRACHYCEPHALIC CRANIA,

Locality. Le De. | Pe De | By Deli Ve Dalit de Agu i Be Dis 0.38 Aa Ce

sas a pened an
Hh Atacama kee Se SSIES Se GEOAT EBED™ WSS MSDN ENS SE ee ere ee metas
Qulestodola. dae bsidiguwe- teste 6:31}, 5.Ora|s Saye, qseee See egs eek
PN Oa Pe eB 6.6...) 5.35 | PSA. shoSnd,|lna-eltest tee - oh 3-3 6a. Seer
AT ee eare Oise ie Seer eda te l= 6.7) |) SsOcgle oO. 04a, |loce ered eee lean ee
OS. OR ARICA Rea. creo « 6.1 | 56 | 34 | 5.1 PA: Omen rotate cnc cee 18.4
Gils Mido sea: Leos 6.4 | 5.1 | 3.2 | 5.1 TAS *s(NAAS ees sso 19.0
Me} eP Cha '5 Ae sabe Lin ca. 6.2 | 5.8 | 37 4.5.6 ES. Lyi], Bee Mite Se 19.1
as |e LeNe eenes aoetl=el= (= 6.3 5.8 3.6 | 5.4 15.6 AD Meet is oi 19.7
Oy MINING AGHEE Steet aic'aioia lace a 6.3 | 5.9 | 4.0 | 5.3 TGQ aA Scere 19.2
RO) fee AO ee 14a) 2 aces «= =n 6.2 | 5.9.")3.4" | 5.0 Tannen |e arses 20.1
Pet sed 2-440). eee 6.5 | 5.9 | 4.0 | 5.3 Losey || Lets 2k 19.5
ANON Se a ee a 65 | 5.2 |} 43 | 51 | 145 | 40+) 13.8 | 18.5
13 | Temple of Sun, F...-.--- 5.80) Bo ol Aa oh Bodh oy TA EL 12.7 | 18.4
Tee EeOO cA octet sete 6.1 | 6.0.) 4.7. |. 5.5 16.0 | 4.5 14.1 |. 19.5
on) eachacamac.. ese ceee 6.7 650) 9194.5." 4) 75:6 Goo earown LAS | 2022
16 G0us..'0 2-2 ee oe 6.3 | 5.8 | 45 | 5.3 15.0 | 4.0 13.2 | 19.0
aD |) Seas OB emer e- eo a= 6.2 | 5.4 ALS il 4.9 14.6 3.8 13.3 18.5
PSR AG a5 .\-m2)-j234 ea eee 6.9: to20) 2 Aco ond 14.7 | 3.8 13.2 | 19.2
19°) Pachacamac,,f)-\.2------ 6.6 6.0 4.6 Du ito Au 13.5 19.8
20 ACO pre eee steele eetciaiat 6.6 | 5.7 4.2 5.2 15.5 | 4.4 13.0 19.4
Oils. < adore se Bie Sense 6.3 | 5.55) 42: | 5.0 14.5 | 3.7 13.2 |. 18.5
Soe setai OG mtstatatn fe wigerate nice 6.3 | 5.3 | 4.4 | 4.6 14.0) hee29 13:0}, |} A830
ee Oia tee hata nearer a 6.4 | 5.5 | 4.3 | 5.2 14.8 | 4.0 13.2 | 19.0
eee s00- eee Mee eeeeee 6.2 | 5.5 | 4.4 | 5.0 13.6 | 3.8 L2G aeua
Bop ie -00-<ccms SUB Shae one aires 6.1) || 5.9 oA 315.2 15.2 | 4.1 13.2 | 19.2
26 2G 38 Bote Se eet 6.2 | 5.8 | 4.3 | 4.9 TA5y | 4.1 > a2 Baka
MeAME eee sepa 6.32 | 5.62 | 4.06 | 5.18 li «14.96 | 4.12 | 13.27 | 19.10

Of the diverse, elongated type of skull, undoubted examples have been re-
peatedly recovered from Peruvian cemeteries, both in their normal condition
and modified by artificial means. They are nearly all small, narrow, and with
a marked predominance of the longitudinal diameter. Several of those meas-
ured by me showed the average distance from a vertical line drawn from the
external auditory foramen to the most prominent part of the frontal bone to be
only 2.7 inches, while from the same line to the most prominent part of the
occipital bone it was 4.3 inches. J ully two-thirds of the cavity occupied by ~
the brain lies behind the occipital foramen, and the skull, when supported on
the condyles, falls backward. Compared with brachycephalic skulls, the fore-
head is low and retreating; the temporal ridges approach near each other at the
top of the head, a much larger space being occupied by the temporal muscles,
between which the skull seems to be compressed. ‘The zygoma is larger, stronger,
and more capacious, and the whole bones of the face are more developed. ‘The
superior maxillary bone is prolonged in front, and the incisor teeth are m an
_ oblique position. ‘The bones of the nose are prominent, the orifices larger, and
the cribriform lamella more extensive; the bony substance of the skull is thicker,
and the weight greater.

Among the numerous interesting illustrations of Peruvian claracteristies ob-
tained by Mr. Blake from ancient cemeteries on the Pacific coast, the most
valuable for the purpose now in view are the skulls of two children, both of the
dolichoeephalic or elongated type; but the one evidently in a normal condition,
while the other betrays manifest traces of artificial deformation. It is impos-
sible to examine the former without feeling convinced that it illustrates a type
of head entirely distinct from the more common brachycephalic crania, while
the latter shows the changes wrought by compression. Figure 3 exhibits the
unaltered skull. It is that of a child, which, judging chiefly from the state of
the dentition, may be pronounced to have been about seven years of age. It is.

PHYSICAL ETHNOLOGY. 251

a well-proportioned, symmetrical skull, unaltered by any artificial appliances,
and will be observed to present the most striking typical contrast, if compared
with an unaltered juvenile skull of the brachycephalic type from the Peruvian
cemetery of Santa, engraved in the Crania Americana, Plate vii. The other
elongated skull, exhibited in Figure 4, is manifestly of the same elongated type
as Figure 3, but considerably altered by ‘compression. The forehead is de-
pressed, and the frontal suture remains open. It is that of a child of about five
years of age; so that both examples are long past the age when the form of the
head admits of material alteration by artificial means.

AW
WH AG
wy NW
M9 a QYaQr
lag \ a

we
wry
Wy
Las
YY

\S

The following measurements give the comparative proportions of the normal
aud abnormal skulls figured above; and of two other children’s skulls, in the
Morton collection, figured in the Crania Americana, Plates ii and vii. They
are marked, A, normal child’s skull; B, abnormal do.; C and D, the Atacama
and Santa skulls of the Crania Americana :

A. Be C D

Longitudinal diameter ..... UO 6.6 6.1 6,9 5.4
Parietal diameter’)... 20205... paren Setters 4.6 4.4 4.5 5.4
Hronteldhiameter U0 eS ee gOce oul aut, A,

Verpreal diameter | 2 0S SI Sn 4.82 4.32 4.3 4.6

From observations carried on in the cemeteries of Peru, Mr. Blake was led
to the conclusion that the distinguishing traits thus far noted between two
classes of the ancient Peruvians are not limited to the erania, but may be dis-
cerned in other traces of their physical organization. In describing those of the
rounded or brachycephalic type of cranium, he adds: “'The bones of the latter
struck me as larger, heavier, and less rounded than those of the former, (the

252 PHYSICAL ETHNOLOGY.

elongated crania,) and in the larger size of the hands and feet they also present
a noticeable difference. The remarkable narrowness and delicacy of the hands,
and the long and regularly-formed finger-nails of the former, are strong evidence
that they were unaccustomed to severe manual labor, such as must have been
required for the construction of the great works of which the ruins remain. In
all the cemeteries examined, where skulls of the rounded form have been found,
those which are elongated have also been obtained.” Remembering, however,
that the sepulchral rites of the royal and noble Inca race were commonly ac-
companied by the same human sacrifices traceable among so many semi-
civilized as well as barbarous nations, it is in no degree surprising that the
crania of the two distinct classes, noble and serf, should be found deposited
together: in the same grave. After a minute comparison of all the brachy-
cephalic Peruvian crania in the Morton collection, it appears to me that these
also admit of subdivision into two classes distinguished by marked physiog-
nomical diversity. ‘The bones of the face in the one are small and delicate,
while the other exhibits the characteristic Mongol maxillary development and
prominent cheek-bones. ‘The following table of measurements illustrates the
proportions of the Peruvian dolichocephalic skull, as shown in examples brought
by Mr. Blake from Peru, and in others preserved in the collections of Boston
and Philadelphia:

TABLE IIIL—PERUVIAN DOLICHOCEPHALIC CRANIA.

Locality. L. D..|P. D. | F. D. | V..D. || iA oT, Ton Hieias eee

Ii) Atacaiiais: 4228. 3220523 V2 5.2 3.6 BMT). aR EE ee ee

Dai dasa sacs. ciel ieek Wes 4.9 oto AD (lesane Sie. Soe See ae

Re BLO sre eis Rt Oe 7.0 Aa 3.2 Bede (|) asec | seats es ee oe

Oe Se Ones esc caries soe sa Weill 5.2 See. 5.0 14.1 4.0 15.0 20.0

BAUS WopAncai ss chee sete e 6.9 5H) 3.6 52 14.6 Ae |e arene 19.8

GripReKdescea=e-nese= aoe V2 5S Oe 5.6 14.6 AL (Qat| £5 OS eee 20.0

7 ~Kd62.sesed% -pebtotce 7.0 4.9 3.0 so 14.0 Aly J fesiehay os 19.0

a eee eee Ong SE oe Wee, Bol 35 5.2 s 13.9 Ac Opes bai Soeeeae 20.0

Or OATICR sass a15 ioe ae eee ‘eo Heo 4.3 5.3 14.0 4.3 15.0 19.8

TOSS Atacams Pei see eee ee 5.5 4.4 5.1 14.8 4.1 13.7 20.2
ATA iticaca2t Hs3BHal ew 6.8 5.4 4.8 5s 14.8 Art Sai Se 19:4
12 | Royal Tombs; Festa 6.8 5.2 3.8 5S 14.1 At Onis) 7k E See 19.4
13) |i-Pachacamac.< 522m ee. 6.8 5.4 4.5 5.3 14.7 4,2 14.1 19.5
Mieanss-scscricccee | O60 ble: | ocoUn) eek | 14.36 | 4.10 | 14.45 | 19.71

In an inquiry into the physical characteristics of the Peruvian nation, we are
by no means limited to the cranial or the mere osteological remains recoverable
from its ancient cemeteries. Like the Egyptians, the Peruvians employed their
ingenious skill in rendering the bodies of their dead invulnerable to the assaults
of “ decay’s effacing fingers ;” and, like the inhabitants of the Nile Valley, they
were able to do so under peculiarly favorable circumstances of soil and climate.
The colors on Egyptian paintings, and the texture of their finer handiwork,
which have shown no trace of decay through all the centuries during which
they have lain entombed in their native soil or catacombs, fade and perish
almost in a single generation when transferred to the humid climates of Paris
or London. The natural impediments to decay probably contributed, alike in
Egypt and Peru, to the origination of the practice of embalming. The ceme-
teries already referred to are situated in a region where rain seldom or never
falls; and the dryness alike of the soil and atmosphere, when added to the
natural impregnation of the sand with nitrous salts, almost precludes the decay

PHYSICAL ETHNOLOGY. 253

of animal or vegetable matter, and preserves the finest woollen and cotton tex-
tures, with their brilliant dyes undimmed by time. By the same means we are
enabled to judge of the color and texture of the hair, the proportions and deli-
cacy of the hands and feet, and the comparative physical development of two
seemingly different races at various stages, from infancy to mature age. When
we pass from the southern continent of America to the seats of ancient native
civilization lying to the north of the Isthmus, a different class of evidence, in
like manner, enlarges our range of observation. ‘The artistic ingenuity of the
ancient Peruvian potter has left valuable memorials of native portraiture, and
the Mexican picture-writing, with the sculptures and terra-cottas, the products
of Toltee and Aztec ceramic art, in like manner contribute important evidence
idustrative of the physiognomy and physical characteristics of the ancient races
of Anahuac. Still more, the elaborate sculptures and stuccoed bas-reliefs of
Central America perpetuate in unmistakable characters the records of an
ancient race, differing essentially from the modern Indian; and the study of
their cranial characteristics serves to confirm the deductions derived from those
other independent sources.

The traditions of the Mexican plateau pointed to the comparatively recent
intrusion of the fierce Mexican on older and more civilized races; and various
independent observers have at different times been tempted to trace associations
between the ancient Mound-builders of the Ohio, the elder civilized race of
Mexico, and the Peruvians, whose peculiar remains are recovered from the
tombs around Lake Titicaca. The predominant Mexican race at the era of the
conquest appears from evidence of various kinds, including the portraiture in
ancient Mexican paintings, to have been derived from one of the great stocks
of the Red Indians of the northern continent. he features represented in the
paintings are thoroughly Indian, and strikingly contrast with those of the
older native race of Central America, as illustrated by their sculptures, bas-
reliefs, and pottery. No doubt, however, the population of the Mexican plateau
in the time of Montezuma included descendants of very different races. All
the traditions of Mexico point to intrusion and conquest by successive invaders ;
and the cranial evidence, as produced in the following tables, shows that there
also, very distinctive types of skull-forms appear to perpetuate the evidence of
diverse races, and of a mixed stock intermingling the characteristics of the con-
quering and the subject people. ‘The same valuable American collections have
furnished the materials for the following comparative tables: .

TABLE IV.—MEXICAN DOLICHOCEPHALIC CRANIA.

|
Locality. TDs Pee De Fee tiveeD I. A Meee | O. B.A. | He G.

—_— = se ees WE fu | |
WiieMextcor Mee 2. 2. 32/2) teil 5.0 SYS) || KD. Wlesoucses LN ae eReeer 19.8
SAhOtumbsy 4-22) sie 2 See Wal 5.6 | 4.6 | 5.5 15.5 | 4.1 15.0 | 20.2
3 | Cerro de Quesilas ------- Tod 5.%f|| 4:40 |) 5.2 15.9) |.4.0 14.0 | 20.5
4 | Acapacingo, F’....------ 6.9 | 5:2 | 4.2 |:5.4,]) 14.5 |, 4.1 14.0 | 19.2
MPL aACMOa ene = — 22 ao 2. eee 7.1 56) | 4.5) | 9-4 | 915.2 | 4.3 34.2 | 20.0
OUPESE COs. 3 322h- bh. 5 2 2~ Sh G.0F | 5.3 | 4:3) 1-553 14.5 | 4.1 14.0 | 20.0
iipMiexico ye +. 22 235- =<) 2S 7.0 5.4 4.3 5.3 15.0 | 4.1 14.0 19.8
SUM ne te gn ne ah 71, [5.5 [44 15.2 | 15.8 | 4.1 | 14.0 | 20.4
Meat 2 = oan lea mae 7.05 | 5.41 | 4.31 | 5.35 || }16.20 | 4.12 44:17) 9.99
ae Lele tai

254 PHYSICAL ETHNOLOGY.

TABLE V.—MEXICAN BRACHYCEPHALIC CRANIA.

Locality. 1. Dee Pe Diy |e Ds Gen Da a kee I. L. | 0. F. A. | H.C.

tel), Mexico) -.4- 226 ee eee 6.6) 9) 5. Biel S- Ohl peo EUG PONG Ns I P| 20.0
OM COE M ac 2a tae eee rem te 6.6 Det ALOv a2 L482 SLO esac 14.5 | 20.0
Sn) Otumba 2 Seer sweey 6.3 5.3 4.4 5.4 1433 PWS WZ 19.2
4 oges i.e ae Be 6.6 Dio 4.4 5.4 14.0 | 4.0 14.0 19.3
Fl Na Crain .ce yet teal aeietas 6.8 5.5 4.6 6.0 15.6 4.4 14.6 19.9
6 | Sanuliorenzoye se oe ie - 6.4 Dad 4.5 5.4 14.6 4.5 SHS 20.2
7 | Mexico, modern -.-----.- 6.6 | 5.3 | 4.3 |] 5.2 14.6 | 4.1 13.6 19.0

ns
Means: S282 ies. 6.56°| 5.51 | 4.30 | 5.55 | 14.69 | 4.25 13.95 | 19.66
|

The Peruvians and Mexicans, with the ancient populations of Central
America and Yueatan, constitute the Toltecan family of the two great divisions
into which Dr. Morton divided his one American “race or species.” The
nations lying to the north of those seats of a native civilization were all classed
by him into one family of the barbarous tribes, resembling the other in physical,
but differing from it in intellectual characteristics. Yet, as we have seen, even
Dr. Morton recognized some differences among them; ‘and Professor Agassiz
speaks of their tendency to split into minor groups, though running really one
into the other. The following tables, however, will show that the differences
are of a far more clearly defined nature, and in reality embrace well-marked
brachycephalic and dolichocephalic forms; while of these, the latter seems de-
cidedly the most predominant. The examples are chiefly derived from the Phila-
delphia collection, though with additional illustrations from the Boston cabinets |
already referred to, as well as from Canadian collections. Table V1, which
illustrates the form of head most widely diverging in proportions from the
theoretical type, shows in reality the prevailing characteristics of the north-
eastern tribes, and could be greatly extended. ‘The opposite or brachyeephalie
eranial formation is illustrated in Table VII.

TABLE VI.—AMERICAN DOLICHOCEPHALIC CRANIA.

P. D. | F. D. | V. | I. A,

Tribe. L. D. I. L. | 0. F. A. | H. €

Ie Seminoles a's = tecis.45 Gel 5.6 4.7 5.5 15.0 Al 14.8 | 20.3
2 OL Ae. . te cise eect, 7.3 5.9 4.6 5.8 15.9 4.4 15:3") =2057
3 Nd OR SaSa ae see tos sae 7.0 5.6 4.7 5.4 15.0 4.1 14.7 20.2
4 FOO ene 7.3 5.6 4.2 5.6 15.2 4.7 15.0 20.4
Ps hO0n Agana eee eee 7.0 5.9 4.5 5.8 14.7 4.6 14.2 20.5
Or Cherokee Ho secs eee We2ialr oven | Are i LO 14.5 | 4.0 14.6 | 20.2
Mmoe: Os. et cetera 7.0 | 5.3 4.1 5.4 14.5 4.0 14.0 19.5
NOs sais ois Mee com eietete 7.2 5.3 4.3 5.3 14.1 4.5 14.0 19.1
FN aecion .:, socahur See 72 |5.0 | 42 |55 | 146 | 39 | 147 } 192
Oe alee es eget ota 7.4 5.9 4.6 5.5 1523 4.7 14.2 is
POO aIC!< = a2 ere em ea 7.0 5.9 4.7 5.5 15.0 4,2 14.2 20.9
JeCinppewa = ---'-----2-: 7.3 | 5.8 | 4.8 | 5.5 15.1 | 4.6 14.2 | 20.9
ESPEN Ge Eee eee eee 7.2 5.5 4.3 5.5 14.8 4.1 14.6 20.2
14 | Pottowatomic ...... -..- 78 157 (44 |53 | 160 | 40 | 15.8 | 224
TW) MUssissavia ie leeiete lace = 7.0 5.2 4.3 5.2 13.8 4.1 14,2 19.5
HG WW elaware tae sence ce = 7.8 5.4 4.6 5.1 14.4 4.2 14.5 20.0
17 een eieteae ie 2 me@ 5:5) 4.4 6.2 15.6 4.3 16.0 21.5
7.6 | 5.3 4.3 5.5 15.0 4.1 15.5 20.5

7.3 | 5.5 4.3 5.5 14.6 4.6 21.0

14.9

PHYSICAL ETHNOLOGY. 255

TABLE VI.—Continued.

Tribe. Ge Ds | Psp a! D. |v. De EA. iW reeqrOs Havse i HE G.
INammikeapi ees -[ --.-= 56 7.4 : ‘ f 15.0 : 14.0
at id

aD 4.4 5.9 ASS) 40) | eee

COR ate ee Ao esate. 6.9 5.0 4,2 Dra 14.3 3.9 14.4 19.8
Aissingboime....2---fch. 7.6 5.8 4.6 Dull 14.9 4.3 14.9 O12
PPE GHEE. soe te BE Wee 50 4.4 ove 14.7 4.6 14.7 20.8
Mandan; tics J... = e'- Goll 5.4 4.3 Hak 14.2 oS 14.6 20.0
Pees ok eit ot ews 7.0 Due 4.1 Has 13.9 As2) 14.1 19.8
pcan oe 2 5 eee 7.0 ‘ah! 4.1 Hil 1335) 4.0 14.0 19.5
IVETE Otero oo ercte spe, Wot Deo 4.5 ey 14.7 4.1 Tass 20.2
Menominee 2s. . 25h a2 oe xe od 5.8 4.1 5.5 14.7 ARC) Realty 20.3
bebe dere coe ect ad We oe a Se a a 1 a tea 19.3
BE AG Oejtin< 26 winds epee Ss 7.5 5.4 4.0 5.5 14.5 ASD app ee! 20.6
Minetart, Hy sess5 92-= <1 ed 4.4 4.4 Dal 14.1 4.1 Na 20.2

Meamlttisas trois 2217-24 | 5.47 | 4.36 | 5.42 14.67 | 4.23 14.62

- TABLE VIIL.—AMERICAN BRACHYCEPHALIC CRANIA.

| | |

Tribe. | L. D. | P. D. | B.D: || WexD. |e bs As I, Ls, |\:O0..F., As, | He Ge

Py Maskogee:: 02 SUN a. 6.8 5.8 4.2 5.6 15.4 4.3 15.0 20.0
SD REN Ofcbarn ctayaters Lye wt af 6.6 Bua 4.5 5:3 15kS 4.5 14.0 20.4
SMW Gh eevee: chart ts eps acs 9 3 6.8 5.4 4.3 Deo 15.0 4.4 14.3 20.1
AM NULY Set esa it ayce oer care | 6.7 5.0 4.2 5.3 14.0 4.1 13.8 19.3
BriMNatiCle ts .2 oo eos | 6.7 bag AL al ad 14.5 4.1 14.3 19.0
GAA Adowees: AS aT | 6.7 5.2 4.3 eo 14.2 3.9 14.1 19.1
Pa WAColmeci-tee ote 6.7 5.7 4.2 5.4 14.7 4.4 13.5 19.8
8 Be eee nee a AR ih 6.8 Eyed) 4.3 5D 15.1 4.4 14.4 20.1
Pea Winer ns aa. 16 6.6 5.4 4.4 4.9 13.7 4.3 13.0 19.1
TOMTOM Fe. oe eee 6.6 5.5 4.1 5.4 15.0 4.4 14.0 19.5
PAPO Lisuss. Ao SPU 6.5 5.5 4.0 5.4 14.8 4.4 14.1 19.3
POR edor ets koeet= Ub aoee's 4 6.7 D0 4.3 Sib Pitre 4.4 14.2 19.6
13-\¢@hetimachee s:4ea%</5:.. 6.5 Hud 4.3 5.9 15.5 4.1 14.0 19.1
145 @himamyam ee ee 6.5 5.4 4,2 5.2 14.3 3.8 13.4 18.8
Pon Osdgoscceseae seas baa 6.6 5.7 4.3 eer ee 4.7 13.8 19.5
16 BL ste renee enacts 6.5 5.9 4.6 ae 15.1 4.1 13.4 19.5
7p @reela a Ie sees eo, Sse 6.9 Bey 4.6 5.4 15.5 4.7 14.4 20.4
LSaREhoGiaw ss 2s)-s8 =). - 28-2 6.5 bel 4.0 4.7 12.5 4.1 13.0 18.7
SB eel he ees es he a8, ese 6.4 Sail 4.0 5.1 14.0 ALO ees) 19.7
20 | ‘*Ohio Mound,” F' ------ 6.4 5.3 3.9 5.0 14.2 ASO Tis 2: .2e 19.0
QipGoajimole 24-52 fee Gr/ EOF OME ns Oetite Pataca eae 13.4 | 19.3
OOelen bdip. esed is wes aos 6.5 | Sel Wiese ALONE Ee Ms 13.0 | 18.5

| |
Midna 3- shh ose 6.62 | 5.45 |; 4.24 | 5.30 14.63 | 4.25 13.85 | 19.44

But I now turn to the region around the northern lakes, where opportunities
of personal observation first suggested to me the obvious discrepancies between
the actual evidence disclosed by exhumation on the sites of native sepulture,
and the theory of a typical unity manifested in the physical and peculiar cranial
characteristics of the most widely-separated tribes and nations of the American
continent. The Scioto Mound skull, characterized by Dr. Morton as “the per-
fect type of Indian conformation to which the skulls of all the tribes from Cape
Horn to Canada more or less approximate,’ presents the remarkable anterior
development of a cranium whereof two-thirds of the cerebral mass was in front

256 PHYSICAL ETHNOLOGY.

of the meatus auditorius externus ; whereas in the elongated Peruvian skull,
unaltered by artificial means, this is almost exactly reversed, showing by the
proportions of the cerebral cavity that fully two-thirds of the brain lay behind
the meatus auditorius. These may be considered as representing the two ex-
tremes; but both of the two great stocks, between whom the northern region
around the great lakes has been chiefly divided since the first intrusion of
Europeans, belong to the dolichocephalic division. 'These are the Algonquins
and the Iroqaois, including in the latter the Hurons, who, with the Petuns,
Neuters, and Eries, all belonged to the same stock, though involved in deadly
enmity with each other. In the supposed typical Scioto Mound skull the lon-
gitudinal, parietal, and vertical diameters vary very slightly; and as the Mexi-
can and Peruvian crania chiefly attracted Dr. Morton’s attention, and are illus-
trated minutely, as a series, in his great work, it only required the further
theory, which referred all the elongated skulls to an artificially modified class,
to confirm in his mind that idea of a peculiarly formed cranium pertaining
uniformly and exclusively to the New World. To the theoretical type of a
head very nearly corresponding in length and breadth, though not in height,
“the most numerous class of Peruvian and Mexican brachycephalic crania un-
questionably approximate. Of one of the former, from the Temple of the Sun,
(Plate xi,) Dr. Morton remarks: “ A strikingly characteristic Peruvian head.
As is common in this series of skulls, the parietal and longitudinal diameter is
nearly the same,” viz.: longitudinal, 6.1; parietal, 6.0; and, tested by this
standard, he was even more justified in recognizing marked points of corre-
spondence between the Mound skulls and what he calls “the Toltecan branch
of the American race,” than might seem reasonable from the miscellaneous
character of the crania referred to by him as “Mound skulls.” But the moment.
we test by actual measurement, a very wide difference is apparent between the
brachycephalie erania of the class referred to, and the prevailing form of the
head in many of the northern tribes, as among the Algonquins, Hurons, and
Iroquois. The Algonquin stock are represented by Ottawas, Mississagas,
Chippewas, and other tribes, within the area of Upper Canada and along the
shores of Lake Superior. Of living Indians belonging to Iroquois and Algon-
quin tribes I have examined, and compared by the eye, many at widely-scat-
tered places: on the Thames and Grand rivers, Rice lake, Lake Simeoe and
the Georgian bay; at Mackinaw in Lake Huron, and at Sault Ste. Marie; at
Ontonagon, La Point, the Apostle islands, and the St. Louis river, on Lake
Superior; and on the Saguenay, St. Charles, St. Maurice, and Ottawa rivers, in
Lower Canada; as well as on such chance opportunities as occur in the neigh-
borhood of American and Canadian towns and villages. Physiognomically they
present the large and prominent mouth, high cheek-bones, and broad face, so
universally characteristic of the American Indian; but they by no means pos-
sess in a remarkable degree the wide and massive lower jaw, which has been
noted as of universal occurrence among the Red Indians; and the aquiline nose
is also abseut in most of them.

The erania found in ancient cemeteries and ossuaries around Lakes Ontario,
Erie, and Huron, chiefly belong to the two families referred to; and of the nation
whose name is perpetuated in that of the last-named lake, the region occupied
by it when first brought under the notice of the French Jesuit fathers is well
defined; so that there is little risk of error in the determination of the race to
which the remains found in its ancient graves belong. <A partial difference in
their relative proportions appears also to aid in the classification of the two
ethnic divisions. The Algonquin cranium, though less markedly dolichocephalic
than the Huron or Iroquois skulls, belongs to the same class; and to one or
other of those ne&rly all the Canadian crania may with little hesitation be as-
signed.

Of Indian skulls chiefly dug up within the district once pertaining to the

PHYSICAL ETHNOLOGY. 257

Huron or Wyandot branch of the Iroquois stock, I had observed and cursorily
examined a considerable number, betore my attention was especially drawn to
the peculiar characteristics now under consideration, owing to repeated rejection
of those which turned up, as failing to furnish specimens of the assigned typical
American head. Since then I have carefully examined and measured seventy
India skulls belonging, as I believe, to the Wyandot or the Algonquin stocks,
with the following resulis:

1. Only five exhibit such an agreement with the assigned American type, as,
judged by the eye, to justify their classification as true brachycephalic crania.
One very remarkable and massive skull was turned up at Barrie, on Lake
Simcoe, within the Iluron region, with upwards of two hundred others. It
differs from all the others in exhibiting the vertical occiput so very strikingly,
that when resting on it, it stands more firmly than in any other position. This
is, without doubt, the result of artificial compression; and in so far as fashion
regulated the varying forms thus superinduced on the natural cranial contorma-
tion, it is suggestive of an intruder from the country lying towards the mouth
of the Mississippi, where the ancient graves of the Natchez tribes disclose many
skulls moulded into this singular form. In some respects, indeed, it presents
features strongly suggestive of comparison with the Scioto Mound skull, while
the smallness of the lower jaw increases its divergence from the Huron or other
northern Indian type. No note has been preserved of the general character of
the crania discovered at the same time; but this one no doubt owed its selection
to its peculiar form. The whole subject of occipital and varied cranial com-
pression is deserving of minuter consideration than is admissible in reference to
the Huron crania, which exhibit in general no traces of an abnormal forma-
tion. Nor is Dr. Morton’s assignment of the vertical occiput as one of the most
characteristic features of the true American cranium borne out by an examina-
tion of those found in Canadian cemeteries. On the contrary, I have been struck
with the evidence afforded by the majority. of skulls examined by me, that such
was certainly no prevailing characteristic of the Huron or other tribes, by whom
Upper Canada was occupied prior to its European settlement. Many of them,
indeed, exhibit a total absence of any approximation to the flattened occiput.
Twenty of the crania referred to show a more or less decided posterior projec-
tion of the occiput: eighteen of these being markedly so; and ten of them pre-
sent such a prolongation of it, as constituted one of the most striking features
in one class of ancient Scottish crania, which chiefly led to the suggestion of
the term kumbecephalic, as a distmetive term for them. But since my observa-
tions on this subject were first published,* the special question of the prevailing
form of the occiput has been taken up in a valuable monograph contributed by
Dr. J. Aiken Meigs to the Transactions of the Academy of Natural sciences
of Philadelphiat The conclusions he arrives at are: that the form of the
human occiput is not constant, but varies even among individuals of the same
race or tribe. He divides the different forms into three primary classes: Ist.
The protuberant occiput, which is exhibited among the nations of the New
World by the Esquimaux, Chippewas, Hurons, and more or less among thirty-
six different American tribes or nations. 2d. The vertically flattened occiput
he assigns as more or less prevalent among sixteen tribes, and characteristic of
the majority of the Mound-builders. 3d. The full and rounded or globular
occiput characterizes nine American nations or tribes, and occurs occasionally
ina greater number. But the final summary of Dr. Meigs goes even further
than this; and, treating as it does, not solely of the American, but of human

* “Supposed prevalence of one Cranial Type throughout the American Aborigines.”—
Canadian Journal, November, 18.7; Ldinburgh New Philosophical Journal, January, 1858.

t Observations upon the Form of the Occiput in the Various Races of Men, by J. Aitken
Meigs, M. D. Phuadelphia, 1800.

17 8

258 PHYSICAL ETHNOLOGY.

occipital formation generally, it very effectually deals with all theories of radical
diversities of human varieties or distinct species, in so far as this important subdi-
vision of osteological evidence is concerned, by atirming, as the result of observa-
tions made on eleven hundred and twenty-five human crania, “that there is a
marked tendency of these forms to graduate into each other, more or less insen-
sibly. None of these forms can be said to belong exclusively to any race or
tribe. None of them, therefore, can be regarded as strictly typical: for a char-
acter or form to be typical should be exclusive and constant.” In his elaborate
observations, Dr. Meigs has still left untouched the peculiarities which distin-
guish the female occiput. One elongated protuberant form appears to me to be
found only in the female head; but a comparative estimate of the occipital
variations in the two sexes, as exhibited in the different races, is necessary to
complete this interesting inquiry.

2. The tendency to the pyramidal form, occasioned by the angular junction
of the parietal bones, is apparent in the majority of the skulls examined. I
have noted its occurrence as a prominent characteristic in twenty-three Canadian
erania, of which ten exhibit a strongly marked pyramidal form, extending to
the frontal bone. Nevertheless, it is by no means constant. Both in the Morton
collection, and in the examples specially noted here, it is only slightly indicated
in some, while in others it is entirely wanting.

3. I am further struck with the very partial projection, and in some
male skulls with the total absence of the superciliary ridge: a characteristic
which, so far as I am aware, has not been noted by other observers. In
some the prominent ridge stretches entirely across the brow, forming a deep
hollow at the junction of the os frontis and the bones of the nose; and this
appears to be the case in the best authenticated Mound skulls. In the Scioto
mound cranium it is markedly so, and it is little less apparent in the Grave
ereek mound, Tennessee, and Mississippi skulls. In this respect they differ
from the majority of the Peruvian crania, with which in other respects they have
been supposed so nearly to agree, that, overlooking this prominent physiognom-
ical feature, the lost Mound-builders have been thought to reappear as the an-
cient architects of Peru. In the great majority of the crania figured by Morton,
the very slight development, and in some, the total absence of a projecting
superciliary ridge, is very noticeable. In thirteen of the Canadian skulls the
same feature is particularly manifest. In the majority of these the os frontis
slopes without any indentation to the edges of the orbits; and when taken into
consideration along with the pyramidal vertex and predominant longitudinal
diameter, suggests aflinities, hitherto overlooked, with the Esquimaux form of
skull.

4. It is also worthy of note that, whereas Dr. Morton states, as the result of
his experience, that the most distant points of the parietal bones are for the
most part. the parictal protuberances: out of fifty-one Canadian skulls, I have
only found such to be the case in three, all of which were female. The widest
parietal measurement is generally a little above the squamous suture, and in
some examples a still wider diameter is given between the temporal bones.
Somewhat minute observations, accompanied in part with measurements, of
numerous examples in the unrivalled collection of the Academy of Sciences of
Philadelphia, and elsewhere, incline me to believe that this is a common charac-
teristic of American crania.

The following tables (Tables VITI, IX) exhibit the relative proportions of
the crania found in Upper Canada, in so far as they can be shown by sucha
series of measurements. Embracing, as they do, the comparative length, breadth,
height, and circumference of sixty-nine skulls, procured without any special
selection from Indian cemeteries, lying, with only four exceptions, to the north
of Lakes Erie and Ontario, they supply a series derived from a sufficient number
to indicate some constant proportions, and to mark certain elements of contrast

PHYSICAL ETHNOLOGY. 259

instead of comparison, when placed alongside of the corresponding relative pro-
portions in the tables of brachycephalic crania.

The measurements in Table VIII are derived from thirty-seven cranfa
obtained from Indian graves in the region around Lake Simcoe, and on the
Georgian bay, the ancient country of the Hurons.

TABLE VIII.—WESTERN CANADA: HURONS.

Locality. i. D;|/(P./D. |BD: | VerDerslt TetAs fete "0. Be Ay ae!
Pe rOm lig <tc cts rere 7.0 | 5.7 | 45 115.6 15.6 | 4.2 15.0 | 21.3,
DYER AO 2k waqe tan ees ates DAL 5:5, WA, | Cone Siang lA: Neo cciae 20.6.
aM EO s Soca ees coreetser soe 7.3 5.7 4.2 Biv 2" Tes 4.3 14.1 | 205
AN esas OO t=) ata iter (areas 7.5 5.6 4.2 5.4 14.7 4.3 14.6 21.1
Fh Re ae eet 7.2 |5.3 | 43 153 || 145 | 4.3 14.3 | 20.3.
Gee 00ers 2a Becee eas 123) sO WA oe) Ord 13.7 | 4.2 14.3 | 20.5
7 | ‘Owen Sound ...--.-..-- WOM ROeD 4.2 | 5.0 ||; 13.8 |.4.0 14°09) 1Oc8
Bale t atoms sea acces se 7.3 |5.3 | 4.3 | 5.3 || 14.4 | 4.2 14.2 | 20.4
OP Bae Oe foaerrweciciceioo's ae 7.2 5.4 3.8 5.2 14.5 3.9 14.2 19.9
NOE ane COs eyeiceret sic cos <fereiwicrsie ‘ed 5.4 4.7 5.6 || 14.6 4.2 15.0 21.4
Mee 00 cee ca loka asic eee es% 4D (Oo 2 180k Nese 15.0 | 4.3 15.6 | 21.8.
lee SOO eee a eince esc <1ot 7.6 5.5 4.5 5.4 14.6 4.5 14.9 | 21.3
13 || Georgian Bay ....:.....- U0 A\FO:6 91 54.29)|15.4 14.6. | -4.7 15.0 | 211
Tae es GO a2) 2cias Wee bis este 6.8 5.2 4.0 5.2 || 13.3 3.8 13.7 19.0
Poles sOOos a2 sess Pe eens 7.4 4.9 4.2 5.3 IS.3) «looser 14.1 | 20D
Ge |POTO 2 co miss cence 56 s155- 7.9 5.6 4.4 5.5 ° 15.6 4.3 15.2 21.4
WIR s800h i clot ace siieenien Tek, NIDA dara 4.3 15.2 | 4.0 14.9 | 20.4,
16s eMedonters. 2.2 o.22 2-25 7:0) 1(5\2 1) a0 215.6 14.8 | 4.5 15.2 | 20.5
TOM dO ta c.a wiscees docies Gee {po WALA: ASB 15.2 | 4.5 14.5 | 2.2
QO see 0 Oe sce as1 = «cicsie siaicie ete 7.6 5.6 4.5 5.6 15.4 4.2 15.0 | 21.4
QIN eet Adon pee ccls sores .s ccs 7.3 5.3 4.2 5.4 14.2 4.1 14.4 | 20.4
22 | Penetaneuishene........ 48 125.0" 24.6 | 15.9 15.5 | 4.5 15:6.- |) 223
QDR: CORE a crdaeiasiess creole ie G9) fh Oo: PPA 6 ALO! “ed Weise cee. 17
Agee Ob ee eieeie ancien ar 7.4 5.4 4.2 5.2 14.5 AA ease eee 20.7,
25 BCL eee tage aetna isos 7.3 5.3 4.2 5.4 14.6 4.1 14.4 20.5
26ulVecumseth: 2222 22/s- 31 7.3 5.6 4.4 5.5 || 14.5 | 4.9 14.4 20.2
Dh aeesesCOes se <2 eacicte.osis 7.2 5.2 3.9 5.0 14.1 3.6 14.2 19.7
BOM ACOs nea eta beaa meena G9 1G.0. 4) SAG #557 16.0 | 3.4 16.1 | 20D
OOF 2 dott. : Bene 7:6 | 5.3 | 4:3+(|-56 14,0- \4.1-- | F438} 902
SOM ees Os Se aioe cin Pyare 2 ayers 7.5 5.2 4.1 5.1 13.4 4.2 14.8 | 20.5
OLN ee OO ee Secrets erie cee 7.4 5.6 4.6 5.5 15.0 4.4 15.0 20.9
Oedbeee Ors ess sae estas 7.6 5.4 4.2 5.7 15.1 4.4 15.3 20.9
So ew bitchurel<.- 22.1.2. ao: | Od 14.25 57 15.1 | 4.2 14.6 | 20.4
34 eNewmarkes: <.<..-ci-,-9<- Meee | 5.6" |) 4G?" 1627 15.7 | 4.2 15.0 | 20.3
BO ae SOO er o:o.2- We sena ae 7.6 5.2 4.1 5.3 14.7 4.0 14.1 19.5
SOMOBKMIPSS. . 2 loo 2 2 7:0 5:9 | 4.0 | 6.0 15.7 | 4.6 15.0 | 21.2
BAA ace tOOs ae oa ae Pees 68 | 4.8 | 4.2 | 5.0 13.6 | 4.0 13.2 | 18.9
}
Means .s.2.adee asics 4.40), 5:43, | 44535))| 5t43 14.66 | 4.23 14.85 | 20.48
|

The localities specified in the following table show the wider region from
whence the skulls have been procured which are assumed to illustrate the cranial
characteristics of the Algonquin stock. he table includes the measurements
of thirty-two Canadian skulls, the whole of which have been obtained from
graves lying to the south and cast of the true Huron country, towards the shores
of Lakes Erie and Ontario, or on the north bank of the St. Lawrence. Some
portions of Western Canada, including localities referred to, were occupied in
the carly part of the seventeenth century by tribes allied to the Hurons; but
on their deserted areas the Algonquins from the north and west have everywhere
preceded the English settlers, and the greater number of the crania introduced
in this table may be assigned without hesitation to Algonquin tribes. No. 23

260 PHYSICAL ETHNOLOGY.

is designated by Dr Morton a Mississaga skull, and probably most, if not all,
of those numbered consecutively from 16 to 28 belong to the same tribe. Nos.
28 to 32 are from Abenakis graves on the St. Maurice. As a whole, the exam-
ples thus grouped together present a suflicient number to furnish some adequate
approximation to the prevailing typical specialties of the Algonquin head.

TABLE IX.—CANADA: ALGONQUINS.

|

Locality. In. Di bps Dy ae aye me a) |e oda alla C,
1 Wwandson=sten so) bas: | POMS Taree Sg ioe lias. Wel Ake el ond
Oo Sasa see eeie ic claoaes 7.0 Ded wince 5.7 16.1 4.0 14.4 20.1
Oye And Oem oefate aes Soca | 7.4 6.1 4.9 Oe a etna | 4.5 15.5 21.4
Ay leon Onset mete ate ne oe 6.6 5.3 4,2 55 14.5 4.2 Tso, 19.0
isle Wat ONC ek sa sieniee ene 6.5 5.2 4.1 5.0 15.4 4.0 13.0 18.4
GulGrandiRiverscankt =.<ace 6.7 5.4 4.2 52 14.3 4,0 13.5 19.3
axe COs ise =e ecenes Semis To 5.6 4.4 5.4 15.0 4.1 15.2 21.0
8 | Burlington Bay......... TOSS oA AIS Ss 14.0 | 4.0 13.6 | 19.5
lars ate OOsraiors o'maobinioe oaeion 7.6 5.6 4.4 5.4 15:2 4:2 14.9 20.9
LOO Nelson, it so s22 2 es 7.9 5.2 4.2 515) 14.0 4.6 15.0 20.4
Pg) yak Ox snes Baa eee, be le 8.2 5:5 4.3 5 14.9 4.3 15.5, 21.0
12 : do...---------------| Mod A eas 5.4 15.0 4.7 1533 | 215
Jape cdo mel cs sakes eed | 7. S0hie Sis Vitae, Vigan TY advo | sao: HY ian 208s
14 So OOn ee eee See To 5.4 4.0 a2) || aa 4.3 14.4 20.5
Pls. Ore gh oo ee eee oe 7.2 5.4 Out Hes elas 4.0 14.3 19.8
1@ River Humber----.-..-.- | ese" aoe eal 5.5 15.4 4.7 14.2 Pale
Wl See ACO aree elects Sse terete | 6.8 56.1) 2425 Hell 14.1 4.5 13.9 19.9
US ee hd Oe. 8 ace Saas eee eden 5.9 4.2 eo 1435 4.2 14,3 20.3
(Op EButwick -escsas5.eeisec ee) Byard) 4.2 5.6 || 16.3 a5 149 2) 2120,
OMe Omen ais tetas sate ee 5.1 4.4 5.6 || 14.3 4.3 14.7 21.0
21, |, Reterboro’ 22.4.5. -<2S-4) FoF v5.00 | 49 |b." i494 O. ae Oa oe
22 eae d0 Seana nate eee te | 7.4 5.3 | 4.2 5.3 || 13.8 4.2 14.1 20.6
+5 Sl a 0 (0 eS Se ene ee | 6.5 Dee 3.9 4.9 13.3 3.8 1337, 1902
CAE ee SOO aee cane ree | 0 5.2 4.3 5D 138 4.1 14.2 19.3
Pig eee, AKO) 2c saa Sete 1 Fel) 156.5 73.9) ING.3) || 45s 0 AS 14.2 20.0
264) Bay of Quinte 2.20.21 AO a DsOalaaeoe kDa TAL oT aed 14.8 oka
Oia Obra a nas eee cee | 7.0 5D 4.2 5.0 14.0 4.6 13.9 20.5
23 lard 0 sasleiniont aois Steen | 74 6.0 4.8 53 14.6 4.7 14.5 20.9
207) St. Maurice... == 52.4220 | 7.0 bee 4.1 553 LO 4.4 14.0 20.5
B0gie- edb ees tas Noten ae 7.5 |b... 5.0. 115.5 14.2 | 5.0 | 14.4 21.0
Bee OO) epee Ie Se ieee 7.0 On yelag, Eye 5s 34.0 4.2 14.5 20.7
$2.| Plies Rivers: 2-2... bd NGS 105.0 bet iW ae 46 15,0) 3021.9

| | | |
Mean esanee tonite | 7.25 | 5.58 | 4.43 | 5.37 || 14.42 | 4.35} 14.42 20.44

But the term Algonquin, though apparently specially employed originally in
reference to Canadian tribes, is now used as a generic appellation of a very
comprehensive kind, and embraces ancient and modern tribes extending from
the Labrador and New England coasts to far beyond the head of Lake Supe-
rior. In this comprehensive use of the term, its application is chiefly based on
philological evidence ; and it points thereby to affinities of language connecting
numerous and widely-severed nations throughout the whole area lying between
the Rocky Mountains and the Atlantic.

The New England tribes are described as having all presented a very uniform
correspondence in their predominant characteristics. Dwight, in his Travels in
Nrw England, says of them: “They were tall, straight, of a red complexion,
with black eyes, and of a vacant look when unimpassioned;” but he ascribes
to them a good natural understanding and considerable sagacity and wit. They
fre not, even now, entirely extinct; bat, lixe others of the eastern tribes that

PHYSICAL ETHNOLOGY. 261

have been long in contact with the whites, it is difficult to find a pure-breed
Indian among the remnants that still linger on some of their ancient. sites.
Judging, however, from the examples I have seen, it is probable that the red
complexion, which Dwight assigns to the New England tribes, may have much
more accurately justified the application of the term Red Indian to the aborigines
first seen by European voyagers along the northern shores of the American con-
tinent than is now apparent when observing the olive-complexioned Chippewas,
Crees, and other tribes of the west. Gallatin has grouped the New England
Indians along with the Delawares, the Powhattans, the Pamlicoes, and other
tribes of the Atlantic sea-board, extending as far south as North Carolina, under
the comprehensive title of Algonquin-Lenapé. There is no doubt that import-
ant philological relations serve to indicate affinities ramning through the whole,
and to connect them with the great Algonquin stock; while the essentially
diverse Iroquois and Huron nations were interposed between them. The result
of a careful examination and comparison of measurements of thirty-two New
England crania, chiefly in the Boston and Philadelphia collections, has been to
determine their classification as decidedly dolichocephalic, and is shown in the
mcan measurements as given in Table X.

Under the double title of Algonquin-Lenapé have been included all the Indian
nations originally occupying the vast tract of the North American continent,
extending from beyond the Gulf of the St. Lawrence to the area of the Florida
tribes, and claiming the whole territory between the Mississippi and the sea,
excepting where the Hurons and the aggressive Iroquois held the country around
the lower lakes, and the Five Nations were already extending their hunting-
grounds at the cost of Algonquin and Lenapé tribes. The mean of the latter,
as given in Table X, is derived from twenty-three crania, chiefly in the Mort-
onian collection; and the mean of the Iroquois crania is based on measurements
of forty-eight skulls from Canadian and other collections.

Thus far the various ethnical groups referred to are all embraced within the
true American stock, of which Dr. Morton and others aflirm a nearly absolute
uniformity of cranial type, or such an approximation to it as serves, in their esti-
mation, to indicate no less clearly the unity of the American race, and its specific
separation, by radical diversity of ethnical characteristics, from all the races of
the Old World. “Identical characters,” says Dr. Nott, “pervade all ihe Amer-
ican race, ancient and modern, over the whole continent.”* Again he says,
«American crania, antique as well as modern, are unlike those of any other race
of ancient or recent times;” and, “at the time of its discovery, this continent
was populated by millions of people resembling each other, possessing peculiar
moral and physical characteristics, and in utter contrast with any people of the
Old World.”’+ These may suflice to illustrate the opinions on this subject reiter-
ated in a variety of forms by various writers, including men of high authority
in questions of science. All, however, concur in excepting from this otherwise
universal uniformity of ethnical characteristics those which pertain to the Esqui-
maux. ‘They are referred to by Dr. Morton as “the only people possessing
Asiatic characteristics on the American continent;’ and the very contrast thus
exhibited between them and all the other races of the western hemisphere has
been assumed as a confirmation of the indigenous unity of the others. But,
while this abrupt contrast in physical form is insisted on, it is acknowledged
that no such philological line of demarkation can be traced; but, on the con-
trary, in language the Esquimaux are thoroughly American.

My opportunities for examining Esquimaux crania have been sufficient to fur-
nish me with very satisfactory data for forming an opinion on the true Arctic
skull form. In addition to the measurements of thirty-eight skulls, from which

* Types of Mankind, p. 291.
t Ibid, p. 296.

262 PHYSICAL ETHNOLOGY.

the Esquimaux mean of Table X is derived, I have recently compared and care-
fully measured six Tchuktchi skulls, in the collection of the Smithsonian Insti-
tution, exhumed from the burial-place of a village called 'Tergnyune, on the
island of Arikamcheche, at Glassnappe harbor, west of Bhering’s straits; and,
during a recent visit to Philadelphia, I enjoyed the advantage of examining, in
company with Dr. J. Aitken Meigs, a series of one hundred and twenty-five
Esquimaux crania, obtained by Dr. Hayes during his Arctic journey of 1860.
The comparison between the Tchuktchi and the true Esquimaux skull is inter-
esting. Without being identical, the correspondence in form is such as their
languages and other affinities would suggest. Of the former, moreover, the num-
ber is too few, and the derivation of all of them from one cemetery adds to the
chances of exceptional family features; but, on carefully examining the Hayes
collection with a view to this comparison, I found it was quite possible to select
an equal number of Esquimaux crania closely corresponding to the Tchuktchi
type: which indeed presents the most prominent characteristics of the former,
anly less strongly marked. In both the skull is long, high, and pyramidal, and,
in the Esquimaux especially, the junction of the parictals is frequently in a keel-
like ridge, which extends into the depressed and narrow frontal bone.

But the same mode of comparison which confirms the ethnical affinities
between the Esquimaux and their insular or Asiatic congeners, reveals, in some
respects, analogies rather than contrast between the dolichocephalic Indian cra-
nia and those of the hyperborean race. The most characteristic features of the
latter, as established by such a comparison, belong to the face, including the
small nasal bones and the prognathous jaw, neither of which pertain to the true
American Indian. The desired comparison may casily be made between the
Troquois or Huron cranium and that of the Esquimaux, from the vertical and
occipital diagrams furnished in the Crania Americana, (pp. 192, 194, 248.)
Bota are elongated, pyramidal, and with a tendency towards a conoid, rather
than a flattened or vertical occipital form; and when placed alongside of the
most markedly typical Mexican or Peruvian heads, the one differs little less
widely from these than the other. ‘The contrast between the Huron and Esqui-
maiux, obvious as it is, may be defined as physiognomical rather than cerebral;
while some of the elements of calvarial correspondence are striking. The charac-
teristics of the Hsquimaux skull are defined by Dr. Meigs as “ large, long, nar-
row, pyramidal; greatest breadth near the base; sagittal suture prominent and
keel like, in consequence of the junction of the parietal and two halves of the
frontal bones; proportion between length of head and height of face as seven to
five; .... forehead flat and receding; occiput full and salient; face broad and
lozenge shaped, the greatest breadth being just below the orbits; malar bones
broad, high, and prominent, zygomatic arches massive and widely separated ;
nasal bones flat, narrow, and united at an obtuse angle, sometimes lying in the
same plane as the naso-maxillary processes’’* But, in reference to the nasal
development, wherein it differs so decidedly from the true Indian physiognomy,
the remarks of Dr J. Barnard Davis are worthy of note. In the Esquimaux
of the eastern shores of Baflin’s bay, he observes, the nasal bones are scarcely
broader, though frequently 'onger than in some Chinese skulls, where they are
50 narrow as to be reduced to two short linear bones. ‘In those of the opposite,
or American shores of Batlin’s bay, they are very different, presenting a length,
breadth, and angle of position almost equal to those of European races having
aquiline noses.”t ‘This slight yet striking anatomical difference seems to supply
a link of considerable value as indicative of a trait of physiognomical character
in the more southern Esquimaux, tending, if confirmed by further observation,
like other physical characteristics already noticed, to modify the abrupt transi-

* Catalogue of Human Crania, A.N.S., 1857, p. 50.
t Crania Britannica, p. 30.

PHYSICAL ETHNOLOGY. 263

tion assumed heretofore as clearly defining the line of separation between the
contrasting Arctic and Red Indian races. In all the arguments based on the
assumed predominance of one uniform cranial type throughout the whole western
hemisphere, the Arctic American. or Esquimaux, has invariably been excluded;
and he has been regarded either as the exceptional example of an Asiatic intruder
on the American continent, or as the hyperborean autochthones of the Arctic
realm, as essentially indigenous there as the reindeer or the polar bear. An
examination of Arctic crania, and a comparison of them with those of some of
the most characteristic among the true Indian tribes, seems rather to suggest
affinities and intermixture; while the same test applied to determine the amount
of diversity among Indian races shows that they also intermingle very clearly
defined elements of ethnical diversity. Dr. Latham, after commenting on the
differences recognizable between the Esquimaux of the Atlantic and the Indians,
adds: ‘It is not so with the Eskimos of Russian America and the parts that
look upon the Pacific. These are so far from being separated by any broad and
trenchant line of demarkation from the proper Indian, or the so-called Red race,
that they pass gradually into it; and that in respect to their habits, manner, and
appearance, equally. So far is this the case that he would be a bold man who
should venture, in speaking of the southern tribes of Russian America, to say,
Here the Eskimo area ends, and here a dfferent area begins.”* ‘The diverse
eographical conformation of the continent, which admits, on its western side, of
requent intercourse and consequent opportunities for intermixture of races,
while, on its eastern side, the Esquimaux is entirely isolated, may account, in
part, for the difference; but, in doing so, it also accounts for the amount of uni-
formity in the physical characteristics of tribes and nations,separated by few
geographical barriers, or well-defined limits, throughout the whole continent;
but among whom, nevertheless, such marked cranial differences are found as the
following table indicates. The mean of only four Mound crania is given, as
they constitute in reality all of the authenticity of which I feel well assured;
and, as their proportions are affected by artificial changes of form, the true
characteristics of the ancient Mound-builders must be held as still depending on
further evidence. ‘The Cave crania, derived from an ancient cave at Steuben-
ville, Ohio, and from the more celebrated Mammoth cave, Kentucky, are included
in Table I.

TABLE X.—COMPARATIVE MEAN CRANIAL MEASUREMENTS.

| |
Gee | Pe De | Bs Del Vie Decl! TAS (| To eo | Os Ps. As | Bee.
——— eos. !
1 | Mound Crania-=2- -.-.-- 6057 | 5.90 | 4.20 | 5.55 | 15.60 | 4. 40 14.00 | 19. 83
el} Cave:Crania:25¢. 3 -< 205 | 6.62 | 5.78 | 4.51 | 5.47 || 14.85 | 4.42 13. 87 | 19.77
Sulebemivaan BiuG.e.- so22.-4 6.32 | 5.62 | 4.06 | 5.18 |} 14.96 | 4.12 13. 27 | 19.10
41, Peruvian). Oxace eccne 7.06 | 5.18 | 3.80 | 5.21 | 14.36 | 4.10 14.45 | 19.71
5 | Mexican B. C 2... 22... 6.56 | 5.51 | 4.30 | 5.55 || 14.69 | 4.25 13.95 | 19.66
GileMexican’ 1): 'C'.. sees s se. 7.05 | 5.47 | 4.31 | 5.35 | 14,20 | 4,12 14.17 | 19.99
‘“leAmerican B. C.2s2e2,2ec2 6.62 | 5.45 | 4.24 | 5.30 14.63 | 4,25 13.85 | 19.44
§| American D.C. 222.2522 7.24 | 5.47 | 4.36 | 5.42 14. 67 | 4.23 | 14, 62 | 20.29
U.| MNOGUOIs, =~. <-2. 2 scat ado O.4¢ |A.aH | 5.44 | 14,65 | 4.24 14. 62 | 20. 49
In| Algonquin 2 -----2s2-222 7.25 | 5.58 | 4.43 | 5.37 | 14.42 | 4.35 |] 14, 42 | 20. 44
11 | Algonquin-Leuapé ------ 7.12 | 5.53 | 4.37 | 5.42 || 14.77 | 4.22 14, 42 | 20.30
a PRs quimalx=.- 2. - 2235 Go2oU Dales) 4.31 |) 5.46 14.48 | 4.18 | 14,82 | 20, 42
| i |

The data from which the above results have been deduced are derived from
the measurements of two hundred and eighty-nine skulls, along with the exami-
nation and comparison of a much larger number. A careful study of Peruvian

* Varieties of Man, p. 291.

264 PHYSICAL ETHNOLOGY.

crania seems to prove that both classes are small, indicating a people of inferior
size and stature, and presenting essential differences, even in the brachycephalic
class, from those of the mounds. Their small vertical diameter is specially
noticeable. In this, as well as in other respects, the greater correspondence
between the Mexican brachycepha!i and the Mound erania is suggestive, and
calculated to increase our desire for the acquisition of a sufficient number ot
examples of both, whereby to test the evidence of physical correspondence
between the elder races of Anahuac and the people who have left such remark-
able evidences of a partially developed civilization in the Mississippi valley. The
two extremes are the Peruvian brachycephali and the Esquimaux—
Length. Breadth. Height. O. F. arch.

Peruviall % < =. 2 Saree 6.32 5.62 She P32
Hsquimaux .....«------- 7.2 O22 5.46 14.8%

But between these the range of variations sufficiently illustrates the fallacy of

the supposed unitorm cranial type affirmed to prevail throughout the whole
western hemisphere from the Arctic circle to Cape Horn.

If the data thus selected as examples of the different groups furnish any
approximation to their relative cranial measurements, it seems scarcely possible
to evade the conclusion that the ideal American typical head has no existence
in nature, and that, it a line of separation between the Peruvian, or so-called
Tolteean head, and other American forms is to be drawn, it cannot be introduced
as heretofore to cut off the Esquimaux, and rank the remainder under varieties
of one type, but must rather group the hyperborean American cranium in the
game class with others derived from widely separated regions, extending <dnto
the tropics and beyond the equator. In reality, however, the resulis of such
attempts at a comparative analysis of the cranial characteristics of the Aimeri-
ean races go far beyond this, and prove that the form of the human skull 1s just
as little constant among the different tribes or races of the New World as of the
Old; and that, so far from any simple subdivision into two or three groups suftic-
ing for American craniology, there are abundant traces of a tendency of devel-
opment into the extremes of brachycephalic and dolichocephalic or kumbeceph-
alic forms, and again of the intermediate gradations by which the one passes
into the other. A much larger number of examples would be required to illus-
trate all the intermediate forms, but sufficient data are furnished here to point in
no unmistakable manner to the conclusion indicated. If crania measuring
upwards of two inches in excess in the longitudinal over the parictal and verti-
cal diameters, or nearly approximating to such relative measurements—wiihout
further reference here to other variations of occipital contormation—may be
affirmed, without challenge, to be of the same type as others where the longi-
tudinal, parietal, and vertical diamete:s vary only by minute fractional ditter-
ences: then the distinction between the brachy cephalic and the dolichocephalie
type of head is, for all purposes of science, ut an end, and the labors of Bium-
enbach, Ketzius, Nilsson, and all who have trod in their fuotsteps, have been
wasted in pursuit of an idle fancy. If differences of cranial conformation of so
stronyly defined a character, as are thus shown tu exist between various ancient
and modern people of America, amount to no more than variations within the
normal range of the common type, then all the important distinctions between
the crania of ancient Kuropean barrows and those of living races amount to
little, and the more delicate details, such as those, for example. which have been
supposed to distinguish the Celtic from the Germanic cranium, the ancient Roman
from the Etruscan or Greek, the Slave from the Magyar or ‘Turk, or the Gothie
Spaniard from the Basque or Morisco, must be utterly valueless. But the legit-
imate deduction from such a recognition, alike of extreme diversities of cranial
form and of many intermediate gradations, characterizing the nations of the
New World as well as of the Old, is not that cranial formation has no ethnic value,

PHYSICAL ETHNOLOGY. 265

but that the truths embodied in such physiological data are as little to be eliminated
by ignoring or slighting all diversities from the predominant form, and assign-
ing it as the sole normal type, as by neglecting the many intermediate gradations,
and dwelling exclusively on the examples of extreme divergence from any pre-
vailing type.

PART Ul.
DESIGNED AND UNDESIGNED SOURCES OF CHANGE IN CRANIAL FORMS.

Among the characteristics of the American typical cranium, as defined by
the author of the Crania Americana, and deduced by others from the evidence
accumulated in that valuable contribution to physical ethnology, considerable
importance is attached to the flattened occiput, which was assumed by him to
be a purely natural feature of the American race. While he recognizes the
elongated type of head pertaining to certain tribes, as the Osages, Missouris,
Mandans, and Blackfeet, he adds: “ Even in these instances the characteristic
truncature of the occiput is more or less obvious ;’’ and in his latest definition
of the specialties of the American skull, hc remarks: “In fact, the flatness of
the occipital portion of the cran um will probably be found to characterize a
greater or less number of individuals in every existing tribe from Terra del
luego to the Canadas.” The celebrated Scioto Mound skull has already been
described, and the artificial origin of its greatly flattened occiput reterred to,
which even Dr. Morton appears to have recognized as surpassiig the limits of
his supposed typical conformation. “ Similar forms,’’ he remarks, “ are common
in the Pcruvian tombs, and have the occiput, as in this instance, so flattened
and vertical as to give the idea of artificial compression; yet this is only an
exaggcration of the natural form, caused by the pressure of the cradle-board in
common use among the American nations.” My own observations on American
crania led me, at an early period, to adopt the opinion not only that such ex-
treme examples of the vertical occiput as are seen in the Scioto Mound and the
Barrie skulls, are the results of artificial pressure, but, as I remarked in 1857,
when submitting my views on Dr. Morton’s supposed American cranial type, to
the ethnological section of the American Association for the Advancement of
Science, it .8 extremely probable that fuither investigation will tend to the
conclusion that the vertical or flattened occiput instead of being a typical
characteristic, pertains entirely to the class of artificial modifications of the
natural cranium familiar to the American cthnologist, alike in the disclosures of
ancicnt graves and in the customs of widely separated living tribes.* The
idea thus expressed received further confirmation from noticing the almost
invariable accompaniment of such traces of artificial modification, with more or
less inequality in the two sides of the head. In the extremely transformed
skulls of the Flathead Indians, and of the Natchez, Peruvians, and other ancient
nations by whom the same barbarous practice was encouraged, the extent of
this deformity is trequent!y such as to excite surprise that it could have proved
com atible with the healthful exercise of any vital functions. But now that
the general subject of artificial compression of the human cranium begins to
receive some degree of minute attention from craniologists, it becomes obvious
that such changes wrought on the nataral form of the head are by no means
peculiar to the American continent, either in ancient or modern times. ‘The
Macrocephali were known to Hippocrates in the fifth century before the Christian
era, as a people who elongated the heads of their intants by artificial means.

© Edin. Philosoph. Journal N. 5., vol. vii, p. 24. Canadian Journal, vol. ii, p. 406,

266 PHYSICAL ETHNOLOGY.

Strabo, Pliny, and Pomponius Mela refer to various Asiatic localities where the
same practice of moulding the head into favored abnormal forms was in use in
their day ; and repeated discoveries in modern times in the Crimea, in the
Austrian valley of the Danube, and even in Sw.tzerland, of similarly distorted
crania, show how widely the practice had been followed in ancient times. ‘The
European examples have been generally referred to the Avarian Huns, but it
affords a striking confirmation of the correspondence between the mode of
practicing this barbarous process in the Old and the New World, that at the
very time when the attention of Retzius and other European craniologists was
specially directed to the subject, an American origin was assigned even to the
European crania. Dr.'T'schudi, guided by his extensive experience as a traveller,
undertook to prove, in a memoir communicated to Miiller’s Archi fur Anatome,
that a skull found near Grafenegg, in Austria, and assigned by Professor
Retzius to the Avars, was in reality an ancient Peruvian relic brought over in
the sixteenth century, when the empire of Charles V. embraced both Austria
and Peru in the same vast dominion. But repeated discoveries of similar arti-
ficially deformed crania, both on European and Asiatic sites, have placed beyond
doubt that the very same processes of malformation practiced by the Peruvians,
the Natchez, and by the barbarous tribes of Oregon, were in use among ancient
European and Asiatic races. But the artificial changes of the human head are
traceable to a variety of causes, all of which require to be maturely considered
in order to rightly estimate the significance of national skull forms. These
causes may be classified thus :

I. Undesigned changes of form superinduced in infancy by bandaging or
other custom of head-dress; by the form of pillow or cradle-board; and by
persistent adherence to any unvarying position in suckling and nursing.

Il. Artificial deformation undesignedly resulting from the habitual carrying
of burdens on the head, or by means of straps or bandages pressing on any
part of the skull, when such is continued from very early youth.

III. Artificial configuration designedly resulting from the application of
mechanical pressure in infancy.

IV. Deformation resulting from posthumous compression, or any mechanical
force brought into operation after death.

T'o each of those causes I have directed some attention in different memoirs ;*
but I now propose to limit my remarks chiefly to one of the aspects of unde-
signed artificial compression in its relation to certain European skull forms.
The influence of such causes in producing some peculiar features of the brachy-
cephalic cranium found in ancient British barrows, was first suggested by me,
in any accessible form, when pointing out the mistake into which Dr. Morton
had fallen in supposing that the irregularity and unsymmetrical conformation
observable in many skulls, but especially in those which have been subjected to
any extreme amount of compression, is peculiar to American crania. The latter
remark, I then observed, is too wide a generalization. 1 have repeatedly noted
the like unsymmetrical characteristics in the brachycephalic crania of Scottish
barrows; and it has occurred to my mind, on more than one occasion, whether
such may not furnish an indication of some partial compression, dependent, it
may be, on the mode of nurture in infancy, having tended, in their case also, if
not to produce, to exaggerate the short longitudinal diameter, which constitutes
one of their most remarkable characteristics.t ‘The idea thus expressed was
founded on observations carried out for some years on the crania of Scottish
tumuli in relation to the general archeology of the country, preparatory to the
embodying of the whole in the “ Prehistoric Annals of Scotland.” Some of

= Edin, Philosoph. Journ. N. S., vol. vii, 24; xiv, 269. Canadian Journal, vol. ii, 406;
vi, 414; viii, 76, 127. Athenzum, Sep. 20th, 1862. Prehistoric Man, vol. ii, 294.
{ Canadian Journal, Nov., 1857.

PHYSICAL ETHNOLOGY. 267

the special views derived from the study of ancient Scottish crania, were sub-
mitted to the ethnological section of the British Association in 1850 ;* and the
general’ facts and deductions in reference to their ethnical significance are
embraced in one of the sections of the above-named work. The subject con-
tinued to occupy my attention so long as I remained in Scotland, and [ availed
myself of every opportunity for adding to the rare materials for its illustration.
While thus engaged my attention was repeatedly drawn to the unsymmetrical
proportions of ancient brachycephalic skulls, and to their peculiar truncated
form, accompanied, as in the Mound skull of the Scioto valley, by an abrupt
flattening of the occiput, which I soon began to suspect was due to artificial
causes. Since then the facilities derived from repeated examinations of Ameri-
can collections have familiarized me not only with the extreme varictics of form
of which the human head is susceptible under the influence of artificial com-
pression, but also with the less-marked changes undesignedly resulting from
such seemingly slight causes a3 the constant pressure of the Indian eradle-board.
The examination and measurement of several, hundred specimens of American
crania, as well as of the living head in representatives of various Indian tribes,
have also satisfied me not only of the existence of dolichocephalic and brachy-
cephalic heads as tribal or national characteristics, but of the common occurrence
of the same exaggerated brachycephalic form, accompanied with the vertical
or obliquely flattened occiput, which had seemed to be characteristic of the
crania of the Scottish tumuli. ‘There are indeed ethnical differences apparent,
as in the frontal and malar bones, but so far as the posterior region of the head
is concerned, both appear to exhibit the same undesigned deformation resulting
from the process of nursing still practiced among many Indian tribes.

The light thus thrown on the habits of the British mother of prchistoric
times, by skull-forms found in ancient barrows, is replete with interest, from the
suggestions it furnishes of ancient customs hitherto undreamt of. But it has
also another and higher va'ue to the craniologist, from its thus showing that
some, at least, of the peculiar forms hitherto accepted as ethnical distinctions,
may be more correctly traced to causes operating after birth.

The first example of this peculiar cranial conformation which attracted my
attention, as possibly traceable to other causes than inherited characteristics, or
natural deviations from the typical skull form of an extinct race, occurred on
the opening of a stone cist at Juniper Green, near Edinburgh, on the 17th of
May, 1851. A slight elevation probably marked the nearly levelled barrow
which had long covered the catacomb and its enclosed memorials of a remote
past, within sight of the Scottish capital. A shallow grave, formed of unhewn
slabs of sandstone, enclosed a space measuring three feet eleven inches in length,
by two feet one inch in breadth at the head, and one foot eleven inches at foot.
The joints fitted to each other with sufficient regularity to admit of their being
closed by a few stone chips inserted at the junction, after which they appeared
to have been carefully cemented with wet loam or clay. The slab which cov-
ered the whole projected over the sides, so as effectually to protect the sepul-
chral chamber from any infiltracion of earth. It lay in a sandy soil, within
little more than two feet of the surface; but it had probably been covered until
a comparatively recent period by a greater depth of earth, as its site was higher
than the surrounding surface, and possibly thus marked the traces of the nearly
levelled tumulus. Slight as this elevation was, it had proved sufficient to pre-
vent the lodgment of water, and hence the cist was found perfectly free from
damp. Within this a male skeleton lay on its left side. The arms appeared to
have been folded over the breast, and the knees drawn up so as to touch the
elbows. The head had been supported by a flat water-worn stone for its pillow ;
but from this it had fallen to the bottom of the cist, on its being detached by

——— a —

© British Association Report, 1850, p. 142.

268 PHYSICAL ETHNOLOGY.

the decomposition of the fleshly ligatures; and, as is common in crania discoy-
ered under similar circumstances, it had completely decayed at the paxt in con-
tact with the ground. A portion of the left side is thus wanting ; but with this
exception the skull was not only nearly perfect when found, but the bones are
solid and heavy ; and the whole skeleton appeared to me so well preserved as
to have admitted of articulation. Above the right shoulder, a neat earthen vase
had been placed, probably with food or drink. It contained only a little sand
and black dust when recovered, uninjured, from the spot where it had been de-
posited by affectionate hands many centuries before, and is now preserved along
with tbe skull in the Scottish Museum of Antiquities.

As the peculiar forms of certain skulls, such as one described by Dr: Thur-
nam, from an Anglo-Saxon cemetery at Stone, in Buckinghamshire,* and another
from an Indian cemetery at Montreal, in Lower Canada,f as well as those of
numerous distorted crania, from the Roman site of Uriconium and other ancient
ecmeteries, have been ascribed to posthumous compression: the precise circum-
stances attendant on the discovery of the Juniper Green cist are important, from
the proof they afford that the body originally deposited within it, had lain there
undisturbed and entirely unaffected by any superincumbent pressure from the
day of its interment. ‘Two, if not three, classes of skulls have been recovered
fiom early British graves. One with a predominant longitudinal diameter, in
the most marked examples differs so essentially in its elongated and narrow
forehead, and oceiput from the modern dolichocephalic head, :hat I was early led
to assign to it a separate class under the name of kumbecephalic or boat-shaped.{
Another las the longitudinal diameter little in excess of the greatest parietal
breadth. In its general proportions, its occipital formation, and even in some’
of its tacial developments. it presents analogies to the American brachycephalie
skull; though it lacks the characteristic fi: sitened and receding forehead. This
British biachy cephalic skull occupies an intermediate place in its relative pro-
portions among ancient British crania, and is no less str.kingly distinguished
from the prevailing modern head, whether of Celtic or Saxon aieas, by its shurt-
ness, than the other is by its lengih, when viewed either in profile or vertically.
The Anglo-Saxon type of skull appears to be intermediate between those two
forms, with a more symmetrical oval, such as is of common occurrence in mod-
ern English heads.

‘The significance of the skull-forms of ancient British graves has been studied
with intelligent zeal in recent years; and the discovery of essentially distinct
types, suggests the inquiry as to traces of the existence of older races in Britain
than the Celtz found in occupation of the islands at the period of Roman inva-
sion. ‘The result of my own observations on such examples of ancient Buitish
crania as were accessible to me, before the interruption of my rescarches in this
department of craniology, by my removal to Canada, was to impress me with
the conviction that the evidence pointed to the existence of more than one early
race; and that traves seemed to be recognizable, suggestive of one characterized
by great length and narrowness of head, a remarkable prolongation of the occi-
put, and poor frontal development. ‘T’o this another appeared to have succeeded
with a short or brachycephalic head, prominent parictal development, and trun-
eated occiput. Accordingly, when the questions involved in such researches and
speculations were brought under the notice of ethnologists in a paper read by
me before the British Association in 1850, I there remarked: ‘ Not the least
interesting of the indications which this course of investigation seems to estab-
lish in relation to the primitive races of Scotland, are the evidences of the exist-
ence of primitive British races prior to the Celts; and also the probability of
these races having succeeded each other in a different order from the primitive

*Crania Britannica, Dee. I, p. 38.
tEdinm. Philosoph. Journal, vi Sy eV Eps 269.
{ Prehistoric Annais of Scotiand, pp. 169, 177,

PHYSICAL ETHNOLOGY. 269

colonists of the north of Europe. Meanwhile, however, these data, and the con-
clusions derived from them, are produced chiefly with a view to induce more
extended research. A much greater accumulation of evidence is requisite to
establish any absclute or certain conclusions ; and this can only be obtained by
a general interest in the inquiry leading to the observation of such, where the
researches of the archeologist, or the chance operations of the agriculturist
afford the desired means.’”* To suggest the possibility of primitive races of
men, not of Celtic origin, having been the earlier occupants of Scotland, appeared,
in 1850, a sufficiently daring extravagance. But the Antiquites Celiiques et
Antédiluviennes of M. Boucher de Perthes, had just issued from the b reich
press; and already, after so brief an interval, we read in familiar phraseology of
the prehistoric man of the Pfahlbauten of Switzerland and France, or ot the
Crannoges of Ireland and Scotland, and the Kjokkenmiddings of Denmark ;
and are no longer startled even to hear of the Flint-Folk of the pre-glacial
period, the contemporaries of the E/ephas primigenius and the Rhinoceros ticho-
rinus. In 1851, before this wonderful revolution in opinion had been brovght
about, my ideas on the prehistoric races of Scotland, and inferentially of Britain,
were set forth in greater detail ;+ but still necessarily accompanied with expres-
sions of’ regret at the inadequate data available for investigations on a subject
then altogether novel. Since then, however, the labors of intelligent students of
science have been rewarded by large and valuable additions to the materials
required for determining the questions dependent on craniological research ; and
special gratitude is due to Dr. J. Barnard Davis and Dr. Thurnam, who have
accomplished in their admirable Crania Britannica the same accumulation of
the requisite data for Britain which Dr. Morton had previously done for America.

With the materials thus furnished for application to the purposes of the
ethnologist, the question has naturally been revived as to the true typical form
of the Celtic cranium, and the possibility of reconciling the existence of such
diverse forms as have already been referred to with the assumed aboriginal
character of the Celts, and the assignment of all crania of an older date than
the Roman period to that race. Bes:des the Saxon skull, with its tribal varia-
tions, including, as Dr. J. B. Davis conceives, the peculiar low and broad form
to which he has given the name of platycephalic, there are, as already stated,
two forms, the one as much shorter as the other is longer and higher than the
average Saxon skull; both of which, on the theory of a primary Celtic abori-
gines, must be included among varieties of the same ethnical group.

If cranial conformation has any significance, it appears to me inconceivable
that two such extreme forms can pertain to the same race; and the circumstances
under which the most characteristic examples of the opposite types have been
found, confirm me in the belief which I advocated when the evidence was much
less conclusive, that the older dolichocephalic or kumbecephalic skull illustrates
the physical characteristics of a race which preceded the advent of the Celie in
Britain, and gradually disappeared before their aggressions. As, however, the
opposite opinion is maintained by so high an authority as Dr. J. Barnard Davis,
the comparison of the following measur ments, illustrative of the three types of
head, will best exhibit the amount of deviation in opposite directions from the
intermediate form. No. 1, like the majority of the same class, is derived from
a megalithic chambered barrow, and has been selected by Dr. Davis as a char-
acteristic example of the class to which it belongs; though, according to him,
that is one of aberrant deviation from the typical British form. No. 2, obtained
from a barrow at Codford, in Wiltshire, has also been selected by Dr. Davis as

* Inquiry into the Evidence of Primitive Races in Scotland prior to the Celta. Report of
Brit. Assoc. 1850, p. 144.

tArchwology and Prehistoric Annals of Scotland.

t Proceedings of the Acad. Nat. Sciences, Philadelphia, 1857, p. 42.

270 PHYSICAL ETHNOLOGY.

one of three typical British crania. It is of the same type as the Juniper Green
skull, and its strongly marked characteristics are thus defined by him: “ Its
most interesting peculiarities are its small size, and its decidedly brachycephalic
conformation. ‘l’his latter character, which commonly appertains to the ancient
British cranium, and even to that form which we regard as typical, is seldom
met with expressed in so marked a manner.”’* No. 3 is a skull from an Anglo-
Saxon cemetery near Litlington, Sussex, one of two of which Dr. Davis remarks :
“There is a general indication of good form in these fine capacious skulls, which
is apparent in every aspect. . . Ona review of the whole series of Anglo-
Saxon crania which have come under our notice, we are led to conclude that
this pleasing oval, rather dolichocephalic form, may best be deserving the epi-
thet of typical among them.”’t All the three examples are male skulls. The
measurements embrace the longitudinal frontal, parietal and occipital diameters,
with the parietal height and the horizontal circumference :

Le DD? | RaDs |) Bs Di) O..Ds'| Pi. BoC.

1. Uley chambered Barrow skull.....-.-...-..-- Bi \eAs Cale Oneill dade 55) 217
PMC acioldiskullee ss ste tes eee he hoe GISn | ANGH | Sa7a lh TOs Ls ae ell:
sssbitlinaton skulls. 22/22 9st -Setctee me anne sole 4a Scan 4307) 429 205.9

Each of the above examples presents the features of the type to which it
belongs with more than usual prominence, so that if the mean of a large series
were taken, the elements of difference between the three would be less strongly
defined. ‘The differences are, however, those on which their separate classifica-
tion depends ; and they thus illustrate the special points on which any cranio-
logical comparison for ethnological purposes must be based. Of the three skulls,
the era and race of one of them (No. 3) are well determined. It is that of a
Saxon, probably of the seventh or eighth century, of the race of the South
Saxons, descended from Adlla and his followers, and recovered in a district
where the permanency of the same ethnic type is illustrated by its predomi-
nance among the rural population at the present day. Another of the selected
examples (No. 2) is assumed by Dr. Davis, perhaps on satisfactory grounds, to
be an ancient British, 7. e., Celtie skull. It is, indeed, a difficulty, which has
still to be satisfactorily expla‘ned, how it is that if this brachycephalic type be
the true British head-torm, no such prevalence of it on modern Celtic areas is to
be found, as in the case of Saxon Sussex connects the race of its ancient Pagan
and Christian cemeteries, by means of the characteristic ovoid skull, with the
Anglo-Saxon population of the present day. The historical race and era with
which Dr. Davis appears to connect the Barrow-builders of Wiltshire, is thus
indicated in the Crania Britannica: “ Region of the Belge, Temp. Ptolemei,
A.D. 120.” The Belge of that era—then apparently comparatively recent in-
truders, and by some regarded as not Celtie but Germanic—were displaced, if
not exterminated ; but the modern Britons of Wales are undoubted descendants
of British Celts of Ptolemy’s age. ‘Though doubtless mingling Saxon and Nor-
man with pure British blood, they probably preserve the native British type as
little modified by foreign admixture as is that of its supplanters in the most
thoroughly Saxon or Anglish districts of England. It is, therefore, a question
of some importance how far the extreme brachycephalic proportions of the so-
called British type may be traceable to other than inherited ethnical character-
istics; whether, in fact, it is not entirely due to the undesigned flattening of the

*Crania Britannica, Dec. ii, pl.14.
t Crania Britannica, Dec. iv, pls. 39, 40.

PHYSICAL ETHNOLOGY. el

occiput, and lateral expansion of the brain and skull, consequent on the use of
the cradle-board.

Meanwhile, turning from this supposed British skull of Roman times to the
one derived from Uley chambered barrow, (No. 1,) the most ancient of the series,
and assuming their chronological order to be undisputed, as it appears to be, we
find no gradation from an abbreviated to an elongated form, but, on the contrary,
an extreme brachycephalic type interposed between the ovoid dolichocephalic
Anglo-Saxon or Christian era and the extreme dolichocephalic or kumbecepha-
lie one belonging to a period seemingly so remote that Dr. Thurnam, when
noting the recurrence of the same type in another chambered barrow at Little-
ton Drew, Wiltshire, remarked: “It is not necessary to admit the existence of
any pre-Celtic race, as the skulls described may be those of Gaelic, as distin-
_ guished from Cymric, Celts; or the long headed builders of these long, cham-

bered, stone barrows, may have been an intrusive people, who entered Britain
from the southwest. Can they have been some ancient Iberian or Ibero Phe-
nician settlers ?’’*

By whatever theory the difference is ultimately accounted for, it is manifestly
one of a nature well calculated to suggest Iberian, Phoenician, Finnie, or any
other diverse origin for the older race, rather than to admit of the belief of Celtic
affinities for it, if the brachycephalic be the true British form. The divergence
from the intermediate form, it will be scen, eXceeds that of the extreme varieties
already referred to among American ecrania, even when the exceptional Esqui-
maux mean is included, as in the following comparative proportions:

Scioto mound skull .......-. 6.50 | 4.50 | 60.0 | 6.20 | 16.00 | 4.50] 13.80 | 19.80
Bamiewskulliv 2: soe%ce 54. 6.60: || 5.20 | 64.0) |.5..30 16. 00 | 4.60 14.40 | 20.70
Efuron;meani. += 22. .-.. 22224- 7.40 | 4.35 | 54.3 | 5.43 | 14.66 | 4.23] 14.65 | 20.48
Esquimaux mean .......-.-- 7,28 | 4.31 | 52.2 | 5.46 | 14.48 | 4.18} 14.82 | 20. 42

If no artificial element were supposed to affect any of those forms, the Barrie
skull would naturally be classed with the former in any such comparison; and
even w th a full recognition of the artificial influences to which, as has been
shown, both appear to have been subjected, it is scarcely conccivable that any
amount of artificial deformation could be employed to transform the long, narrow,
and high Esquimaux cranium into either form. The markedly brachycephalie
proportions of each are traceable in part to the parieto-occipital flattening ; but
the symmetrical uniformity which characterizes both proves that they are only
modified examples of naturally short and broad ecrania. But the vertical or
obliquely flattened occiput, which even Dr. Morton recognized as, in its extreme
manifestations, traceable to artificial compression, is by no means peculiar to the
New Worl; aad the importance of determin‘ng whether it is to be regarded as an
ethnical characterisiic, or merely an artificial result of external influences applied
designedly or in the practice of some common usage, will be apparent when
its prevalence has been recognized. Meanwhile, the suggestion of Dr. Thur-
nam, that the long-headed race of the British isles may possibly be traceable to
Iberian or Phoenician intruders, invites attention to whatever materials may be
available for the determination of the skull-forms of those ancient races.

Among the rarer crania of the Morton collection is one to which a peculiar
interest attaches, and which may possibly have some significance in reterence to
this inquiry. Its history is thus narrated in Dr. Henry S. Patterson’s Memoir

* Crania Britannica, Dee. iii, pl. 24, (4.)

272 PHYSICAL ETHNOLOGY.

of Dr. Morton: During a visit of Mr. Gliddon to Paris, in 1846, he presented a
copy of the Crania dAsgyptiaca to the celebrated oriental scholar, M. Iresnel,
and excited his interest in the labors of its author. Upwards of a year after
he received, at Philadelphia, a box containing a skull, forwarded from Naples,
but without any information relative to it. ‘It was handed over to Morton,”
says Dr. Patterson, “who at once perceived its dissimilarity to any in his
possession. It was evidently very old, the animal matter having almost entirely
disappeared. Day after day would Morton be found absorbed in its contem-
plation. At last he announced his conclusion. He had never seen a Phoenician
skull, and he had no idea where this one came from; but it was what he con-
ceived a Phoenician skull should be, and it could be no oéher.”’* Six months
afterwards Mr. Gliddon received, along with other letters and papers forwarded
to him trom Naples, a slip of paper, in the handwriting of M. Fresnel, contain-
ing the history of the skull, which had been discovered by him during his
exploration of an ancient tomb at Malta. Dr. Meigs refers to this in his catalogue
of the collection, (No. 1352,) as an illustration ef the “ wonderful power of dis-
crimmation, the tactus visus, acquired by Dr. Morton in his, long and critical
study of craniology.”” Such was my own impression on first reading it; but 1
confess the longer I reflect on it the more am I puzzled to guess by what classical
or other data, or process short of absolute intuition, the ideal type of the Phoenician
head could be determined. I suspect, therefore, if we had the statement of Dr.
Morton's own words, it would fall short of such an absolute craniological in-
duction. ‘The following is the sole entry made by him in his catalogue: “Ancient
Pheniciin? IL received this highly interesting relic from M. 8. Fresnel, the
distinguished French archeologist and traveller, with the following memorandum,
A D. 1847:—Crane provenant des caves sépulchrales de Ben-Djemma, dans
Vile de Malte. Ce crane parait avoir appartcnu a un individu de la race qui,
dans les temps les plus anciens, occupait la cété septentrionale de |’ Afrique, et
les iles adjacentes.”” The sepulchral caves of Ben-Djemma are a series of
galleries with lateral chambers or catacombs hewn in the face of the clifts on
the southwest side of the island of Malta. Other traces besides the rock-hewn
tombs indicate the existence of an ancient town there, although no record of its
name or history survives. M. Vrédérick Lacroix remarks, in his Madre et le
Goze, “‘ Whoever the inhabitants of this city may have been, it is manifest from
what remains of their works that they were not strangers to the processes of art.
The sepulchral caves, amounting to a hundred in number, receive light by means
of litile apertures, some of which are decorated like a finished doorway. In
others, time and the action of the humid atmosphere have obliterated all traces
of such ornaments, and left only the weathered rock. . . The chambers set
apart for sepulture are excavated at a considerable distance from the entrance,
in the inmost recesses of the subterranean galleries. The tombs are of admirable
design and style of art, and the details of their execution exhibit remarkable
ingenuity and purity of taste. The author of the Voyage Pi toresque de Sicile
does not hesitate to declare that they surpass in elegance any that he has seen
exccuted on the same scale. What hand has hewn out these gloomy recesses
in the rock? ‘To that we can give no reply. ‘The chronicles of Malta are silent
on this point. Time has detaced the vestiges which might otherwise have
helped to the solution of the problem.” t

Other and very remarkable remains of antiquity abound in Malta and the
neighboring island of Goza, includmg the cyclopean ruins styled La tour des
Geants, Which have also been assigned by some writers to a Phoenician or Punie
origin, as a temple dedicated to Astarte; and the Tadarnadur Isrira, a mega-
lithic structure for which a Pelasgic origin is assumed. But in drawing any
comparison between the chambered galleries of Ben-Djemma and the megalithie

* Memoir of Samuel G. Morton, p. xl.
t Malie et le Goze, p. 21.

PHYSICAL ETHNOLOGY. 2738

chambered barrows or cairns of the British Islands, we are at best reasoning
from the little known to the less known indices of prehistoric races; between
which the points in common may amount to no more than those which admit of
a comparison being drawn between the Brachycephali of the British Stone-
Period, and the corresponding physical form and rude arts of American grave-
mounds.

Nevertheless the Ben-Djemma skull in the Mortonian collection is not im-
probably what it has been assumed it to be; and it is in many respects a
remarkable one. A deep indentation at the nasal suture gives the idea of an
overhanging forehead, but the superciliary ridges are not prominent, and the
peculiar character of the frontal bone is most strikingly apparent in the vertical
view, where it is seen to retreat on either side, almost in a straight line from
the centre of the glabella to the external angular processes of the frontal bone.
The contour of the coronal region is described by Dr. Meigs as “a long oval,
which recalls to mind the kumbecephalic form of Wilson.”* It is of more
importance, perhaps, to note that the remarkable skull recovered by Dr.
Sehmeréng, from the Engis Cavern, on the left bank of the Meuse, buried five
feet in a breccia, along with the tooth of a rhinoceros and other fossil bones,
appears to be of the same elongated dolichocephalic type. Its frontal develop-
ment is long and narrow; and its greatest relative proportion, in length and
breadth, are 7.7 by 5.25 inches, so that it closely corresponds in those respects
to the most characteristic British kumbecephalie crania.” t

Whatever be the final conclusion of ethnologists as to the evidence which led
me to adopt that name to indicate the characteristics of a pre-Celtic British race,
the necessity appears to be acknowledged for some term to distinguish this form
fromthe ordinary dolichocephalictype. The Ben-Djemma skullis narrow through-
out, with its greatest breadth a little behind the coronal suture, from whence it
narrows gradually towards front and rear. ‘The lower jaw is large and massive,
but with less of the prognathous development than in the superior maxillary.
The skull is apparently thet of a woman. The nose has been prominent; but
the zygomatic arches are delicate, and the whole face is long, narrow, and
tapering towards the chin. ‘The parictals meet at an angle, with a bulging of
the sagittal suture, and a slight but distinctly defined pyramidal form, ranning
into the frontal bone. 'The occiput is full, round, and projecting a little more on
the left side than the right. ‘The measurements are as follows:

HLoneitudmealndiametens: 3. Soai.2 8G Voces hee se oe 7.4
amie harTaMe Ler ey. an ihc eats eal ieee Pe NST FS ans 5A
Prombal <diameteries a eek eB Fed abc a 2s8 oie bie wsciere crete 4
Mierticaltdrametenie: 222) Sa. sc iase sclhs BRS TOR eo 3.3
IML SRIMeatOlearelneee tk ct Sees tees een Sake peas 12:3
itenmasioid@aren.. tesco iAee sc, ooo Nncco oe eat le 15 (%)
HUTESTEN ASEOTE IIe: oe bates, heck era's. Spe, c) date aio oes cicie oa 4.3(?)
Occipito-fromtal archy. 22.221 .- ayaa TAI eEe eeteed tieeegae =. pm 14.2
iEonmzontaly eigcumierence.o 1. a ai. huis celle. ae os 20.2

IT have been thus particular in describing this interesting skull, because it
furnishes some points of comparison with British kumbecephalic crania, bearin
on the inquiry whether we may not thus recover traces of the Phoenician
explorers of the Cassiterides in the long-headed builders of the chambered
barrows. When contrasting the wide and nearly virgin area with which Dr.
Morton had to deal, with that embraced in the scheme of the Crania Britannica,
T remarked in 1857:—Compared with such a wide field of investigation, the
little island home of the Saxons may well seem narrow ground for exploration,

* Catalogue of Human Crania in the Academy of Nat. Sciences of Philadelphia, p. 29.
t Lyell’s Antiquity of Man, p. 81.

18 s

274 PHYSICAL ETHNOLOGY.

But to the ethnologist it is not so. There, amid the rudest traces of primeval
arts, he seeks, and probably not in vain, for the remains of primitive European
allophyliz. 'Vhere it is not improbable that both Phoenicians and early Greek
navigators have left behind them evidences of their presence, such as he alone
can discriminate.* The Phoenicians stand, for northern Europe, as the oldest
of all the ancient civilized nations of the world, to whom its seas, ports, and
mineral treasures were known. Not unnaturally, therefore, there is a disposition
to turn to them as a means of explaining all mysteries. Professor N.isson, in
the new edition of his Skandinaviska Nordens Urinvdnare, ascribes to a sup-
posed Pheenician occupation of the North the whole of the characteristic works
of art of its Bronze period; and the temptation is still stronger for the British
archeologist and craniologist to resort to a similar theory. ‘The intercourse be-
tween Phoenicia and the ancient Cassiterides, by indirect, if not by direct,
traffic, is undisputed. But the evidence of any Phoenician settlements in Britain
rests on inferences from very vague allusions; and Sir George Cornwall Lewis
has done his best to invalidate them. Summing up the results of his inquiry as
to the nature of the classical evidence in favor of the Phoenicians having
directly traded with Britain for its mineral wealth, and especially its tin, he
remarks: “On the whole, the accounts preserved by the Greek and Latin
writers lead to the inference that the tin supplied in early times to the nations
in the east of the Mediterranean came by the overland route across Gaul, and
that the Pheenician ships brought it from the mouth of the Rhone, without
sailing as far as Britain.’ + British antiquaries will not willingly adopt such an
opinion; but it serves at any rate to indicate how slight is the evidence on
which to base any theory of a Phoenician origin for the ancient long-headed
kumbecephali of the British Isles. Moreover, such a theory, in so far as it has
any craniological basis, rests only on the recognition of the general analogy of
form between certain British crania and the supposed Punic one brought from
Malta; while it derives no confirmation from the discovery of works of art in
the chambered barrows, or other sepulchres of the long-headed British race,
such as can be ascribed to a Phoenician origin, or indicate any trace of Punic
influence.

But there is another and more important aspect of the question. Before we
can abandon ourselves to the temptations which the Punie theory offers, it has
to be borne in remembrance that it is still disputed with reference to this class
of British dolichocephalic crania. Are they examples of an essen@ally distinct
type, preserving evidence of the characteristics of a different race, or are they
mere exceptional aberrant deviations from the supposed brachycephalic Celtic
or British type? Much stress is laid on the fact that the two forms of skull
have occasionally been recovered from the same barrow; from which it may be
inferred that the two races to which | conceive them to have belonged were, for
a more or less limited period, contemporaneous. More than this I cannot regard
as a legitimate induction from such premises, in relation to crania of such
extremely diverse types. But this amounts to little, for the same is undoubtedly
true of the ancient British and the modern Anglo-Saxon race; and the discovery
of Celtic and Saxon skulls in a common barrow or tumulus of the 6th century is
no proof that the latter race was not preceded by many centuries in the occupa-
tion of the country by the Britons, among whom they then mingled as conquerors
and supplanters.

But the elongated skulls of the Uley barrow type are no rare and exceptional
forms. They have been most frequently found in tombs of a peculiar charac-
ter, designated chambered barrows, from the galleries and catacombs of large
unhewn stones which they contain. 'To these tombs archzeologists are unani-

* Canadian Journal, vol. ii, p. 445.
} Historical Survey of the Astronomy of the Ancients, p. 455.

PHYSICAL ETHNOLOGY. 275

mous in assigning great antiquity. The late Mr. Thomas Bateman, of Lomber-
dale House, Derbyshire, soon after the publication of my first views relative to
the pre-Celtice era of the long-headed race, or kumbecephali of Scotland, stated
that in the Derbyshire long barrows, explored by him, “the boat-shaped skull
had uniformly been found, rarely accompanied by any instrument, but, in one or
two cases, with arrow-points of flint.”* To this opinion subsequent researches,
extending through successive years to 1858, appeared to him to lend conrfirma

tion; and, in his “Ten Years’ Diggings in Celtic and Saxon Grave Hills,” pub-
lished in 1861, much additional evidence is produced. In describing some
remarkable disclosures in Longlow barrow, he remarks: “This is the first oppor-
tunity we have had of exploring an undisturbed cist in a chambered cairn of
this peculiar structure. It is, on this account, a discovery of unusual interest,
and, when compared with the results of previous or subsequent excavations in
similar grave-hills, yields to none in importance. The mound, composed of
stone, inclosing a chamber or cist formed of immense slabs of stone, occasionally
double or galleried, indicates, in this part of the country at least, a period when
the use of metal was unknown, the sole material for the spear and arrow being flint,
which is often carefully chipped into leaf-shaped weapons of great beauty. ‘The
interments within these cists have in every case been numerous, and apparently
long continued. ‘They are marked by a strongly defined type of skull, styled
by Dr. Wilson kumbe-kephalic, or boat-shaped, the more obvious features being
excessive elongation, flattening of the parietal bones, and squareness of the base,
producing, when viewed from behind, a laterally compressed appearance, which
is enhanced by the sagittal suture being sometimes clevated into a ridge. The
adult male skull found in the centre of the Longlow cist has been selected to
appear in the Crania Britannica as a typical example of this form. The erania
of a female and of a girl about seven years old, from the same cist, exhibit the
same form in a remarkable degree, as do the others which are more imperfect.’’t
In the majority of cases the like imperfection has prevented more than the dedue-
tion of such general correspondence. Nevertheless, the number already obtained
in a sufficiently perfect state to admit of detailed measurement is remarkable,
when their great age and the circumstances of their recovery are fully considered.
Of this the following enumeration will afford satisfactory proof. Only two perfect
erania from the chambered tumulus of Uley, in Gloucestershire, of which the
proportions of one are cited above, have been preserved. But, in the later
search of Mr. Freeman and Dr. Thurnam, in 1854, the fragments of eight or
nine other skulls were recovered, and of these the latter remarks: “The frag-
ments are interesting, as proving that the characters observed in the more perfect
crania were common to the individuals interred in this tumulus. Three or four
ealvaria are sufficiently complete to show that in them likewise the length of the
skulls had been great in proportion to the breadth.”t Again, in the megalithic
tumulus of Littleton Drew, North Wilts, at least twenty-six skeletons appear to
have been found, from several of which imperfect crania were recovered, and of
those Dr. Thurnam remarks: “ Eight or nine crania were sufficiently perfect for
comparison. With one exception, in which a lengthened oval form is not marked,
they are of the dolichocephalic class.Ӥ So also the four nearly perfect skulls
from West Kennet are described as ‘more or less of the lengthened oval form,
with the occiput expanded and projecting, and presenting a strong contrast to
skulls from the circular barrows of Wilts and Dorset.’”’|| To these may be
added those of Stoney Littleton, Somersetshire, first pointed out by Sir R. GC:
Hoare ;{{ and examples from barrows in Derby, Stafford, and Yorkshire, de-

* Journal of Archwol, Association, Vol. VII, p. 211.

t'Ten Years’ Diggings in Celtic and Saxon Grave Hills, p. 95.

} Arch@ol. Journal, vol. xi. p. 313. Crania Britannica, Dee. I, pl. 5, (5.)
§ Crania Britannica, Dec. LI, pl. 24, (3.)

| [bid, Dec. V, pl. 50, (4.)

] Archeologia, yol. xix, p. 47.

276 PHYSICAL ETHNOLOGY.

scribed by Mr. Thomas Bateman in his “Ten Years’ Diggings in Celtic and Saxon
Grave Hills;” including those from Bolehill, Longlow, and Ringham Low,
Derbyshire; from the galleries of the tumulus on Five Wells Hill; and from
the Yorkshire barrow, near Heslerton-on-the-Wolds. Several of the above con-
tained a number of skulls, and, of the last, in which fifteen human skeletons lay
heaped together, Mr. Bateman remarks: “The crania that have been preserved
are all more or less mutilated, but about six remain sufficiently entire to indicate
the prevailing conformation to be of the long or kumbecephalic type of Dr.
Wilson.’”* 'The crania occurring in graves of this class, mentioned by Mr. Bate-
man alone, exceed fifty in number, of which the majority are either of the elon-
gated type or too imperfect to be determined. The others include between thirty
and forty well-determined examples, besides a greater number in too imperfect a
state to supply more than indications of their correspondence to the same char-
acteristic form. Alongside of some of these are also found brachycephalic cra-
nia; but, in the most ancient barrows, the elongated skull appears to be the predom-
inant, and, in some cases, the sole type; and of the examples found in Scotland,
several have been recovered from peat bogs, or others under circumstances more
definitely marking their great antiquity.

The variations of cranial form are thus, it appears, no gradual transition, or
partial modification, but an abrupt change from an extreme dolichocephalic to an
extreme brachycephalic type; which, on the intrusion of the new and essentially
distinct Anglo-Saxon race, gives place once more to a dolichocephalic form of
medium proportions. The three forms may be represented, reduced to an abstract
ideal of their essential diversities, by means of the following diagrams: No. 1,
the kumbecephalic head of the chambered barrows; No. 2, the dolichocephalie,
or supposed British type; and No. 3, the ovoid Anglo-Saxon head, still predom-
inant.

Fig. 5.

No. 1. No. 2. No. 3.

Leaving, meanwhile, the consideration of the question of distinct races indi-
cated by such evidence, it will be well to determine first if such variations of
skull-form can be traced to other than a transmitted ethnical source. One of
these, No. 2, presents many unmistakeable analogies to the most common Amer-
ican form; in so much so that, before I was familiar with the latter, otherwise
than through the pages of the Crania Americana, I selected two of the most
characteristic brachycephalie crania figured and described there, as the fittest for
illustrating the typical characteristics of the Scottish skulls of short longitudinal
diameter.t Of the same characteristic brachycephalic form the Barrie skull,
(Fig. 6,) is a well defined example. Found in an Indian cemetery, on a conti-
nent where the craniologist is familiar with examples of the human head flat-
tened and contorted into the extremest abnormal shapes, and where the influence
of the Indian cradle-board in increasing the flattened occiput had long since been

$a

* Ten Years’ Diggings in Celtic and Saxon Grave Hills, p. 230.
t Prehistoric Annals of Scotland, p. 167.

PHYSICAL ETHNOLOGY. Qik

pointed out by Dr. Morton: the peculiar contour of the Barrie skull excited no
more notice than the recognition of it as one well-known variety of American
cranial forms. But, when almost precisely the same form is found in British
graves, it is suggestive of ancient customs hitherto undreamt of, on which the
familiar source of corresponding American examples is calculated to throw a
novel light.

<a

Fig. 6. Fig. 7.

Of this form the Juniper Green skull, previously referred to as discovered in
the immediate vicinity of Edinburg, is a striking example. It has been
engraved the full size in the Crania Britannica, and, as will be seen, it presents
in profile «he square and compact proportions characteristic of British brachy-
cephalic crania. It also exhibits, in the vertical outline, the truncated wedge
form of the type indicated in Fig. 5, No. 2. In the most strongly marked exam-
ples of this form, the vertical or flattened occiput is a prominent feature, accom-
panied generally with great parietal breadth, from which it abruptly narrows at
the occiput. The proportions of this class of crania were already familiar to me
before the discovery of the Juniper Green example, but it had not before
occurred to me to ascribe any of their features to other than natural causes. But
the circumstances attending its exhumation gave peculiar interest to whatever
was characteristic in the skull and its accompanying relics, handled for the first
time as evidences of the race and age of the freshly opened cist, discovered
almost within sight of the Scottish capital, and yet pertaining to prehistoric
times. This interesting skull was deposited in the Museum of the Scottish Anti-
quaries, along with the urn which had lain beside it in the rude cist, and I
accompanied its presentation with the first expression of my suspicion—for it
scarcely then amounted to more—that the flattened occiput was due to some arti-
ficial compression, by means of which the abbreviated form so common in crania
of the Scottish tumuli had been exaggerated if not entirely produced.

Another skull in the same collection, found under somewhat similar circum-
stances in a cist at Lesmurdie, Banffshire, has the vertical occiput accompanied
by an unusual parietal expansion and want of height, suggestive of the idea of
a combined coronal and occipital compression.* A third Scottish skull, pro-
cured from one of a group of cists near Kinaldie, Aberdeenshire, also exhibits
the posterior vertical flattening. But a more striking example than any of those
appears in the one from Codford, South Wiltshire, selected here to illustrate this
type. Dr. Davis remarks, in his description of it: “The zygomatic arches are

* Vide Crania Britannica, Dec. II plate 16.

278 PHYSICAL ETHNOLOGY.

short, a character which appertains to the entire calvarium, but is most concen-
irated in the parietals, to which the abruptly ascending portion of the occipital
lends its influence. The widest part of the calvarium is about an inch behind,
and as much above the auditory foramen, and, when we view it in front, we per-
ceive it gradually to expand from the outer angular process of the frontal to the
point now indieated.”’ The entire parieto-occipital region presents in profile an
abrupt vertical line; but, when viewed vertically, it tapers considerably more
towards the occiput than is usual in crania of the same class.

Tic. 8. Fig. 9.

A comparison of this skull, recovered from an ancient British grave, with the
one obtained in an Indian ossuary in Barrie, in Upper Canada, shows the squarer
form of the British skull, when seen in profile, dependent in part on the more
elevated and well arched frontal bone. But, in the vertical view, the Indian
skull shows its extreme brachycephalic character; being at once shorter and
broader than the British one, though the latter is one of the most strongly
marked of its class. The vertical character of the occiput is also strikingly dis
played. In other examples the flattening chiefly affects the parietal bones
extending in an oblique line towards the coronal suture.

The origin of both, as artificial forms superinduced on a naturally short anc
broad type of skull, I feel no hesitation in believing to be traceable to the same
kind of rigid cradle-board as is in constant use among many of the Indian tribes
of America, and which produces precisely similar results. Its mode of opera-
tion, in effecting the various forms of oblique and vertical occiputs, will be best
considered when describing some of the phenomena of compressed Indian
crania; but another feature of the Juniper Green skull, which is even more ob-
vious in that from Lesmurdie, in the same collection, is an irregularity amounting
to a marked inequality in the development of the two sides. This occurs in
skulls which have been altered by posthumous compression; but the recovery
of both the examples referred to from stone cists precludes the idea of their
having been affected by the latter cause; and since I was first led to suspect
the modification of the occiput, and the exaggeration of the characteristic pro-
portions of British brachycephalie crania by artificial means, familiarity with
those of the Flathead Indians, as well as other ancient and modern artificially
distorted American crania, has led me to recognize in them the constant oceur-
rence of the same unsymmetrical inequality in opposite sides of the head.

The inequality in the development of the opposite sides of the above skulls
belongs to the same class of deformations as the well-known distortions produced

PHYSICAL ETHNOLOGY. 279

on many American crania, both by the undesigned action of the exadle-board,
and by protracted compression purposely applied with a view t6 chenge the
form, merits the careful attention ef craniologists. The normal human head
may be assumed to present a_ perfect correspondence in its two hemispheres ;
but very slight investigation will suffice to convince the observer that few living
examples satisfy the requirements of such a theoretical standard. Not only is
inequality in the two sides frequent, but a perfectly symmetrical head is the
exception rather than the rule. The plastic condition of the cranial bones in
infancy, which admits of all the strange malformations of ancient Macrocephali
and modern Flatheads, also renders the infant head liable to many undesigned’
changes. From minute personal examination I have satisfied myself of the
repeated occurrence of inequality in, the two sides of the head, arising from the
mother being able to suckle her child only at one breast, so that the head was
subjected to a slight but constantly renewed pressure in the same direction. It
is surprising, indeed, to how great an extent such unsymmetrical irregularity is
found to prevail, when once the attention has been drawn to it. The only ex-
ample of the Greek head possessed by Dr. Morton was a cast presented to him
by Dr. Retzius, and which, from its selection by the distinguished Swedish
craniologist for such a purpose, might reasonably be assumed to illustrate the
Greek type. It is accordingly described by Dr. J. Aitken Meigs, in his “ Cra-
nial Characteristics of the Race of Man,” as very much resembling that of
Constantine Demetriades, a Greek native of Corfu, and long a eachen of the
modern Greek Janguage at Oxford, as engraved im Dr! Prichard? s Researches.
Its cranial characteristics are thus defined in the Vatalogue of the Mortonian
Collection, (No. 1354.) ‘Che calvarial region is well developed, the frontal
line expansive and prominent, the facial line departs but slightly from the per-
pendicular.”” On recently visiting Philadelphia for the purpose of renewed
examination of its valuable collections, I was surprised to find this head—instead
of being either oval, or, as Blumenback describes the example selected by him,
sub-globular—presenting the truncated form, with extreme breadth at the parietal
protuberances, and then abruptly passing to a flattened occiput. It measures
6.5 longitudinal diameter ; 5.7 parietal diameter; and 19.2 horizontal circumfer-
ence. But the most noticeable feature is the great inequality of the two sides.
The right side is less tumid than the left, while it projects more to the rear, and
the whole is fully as unsymmetrical as many American crania. Were it not
that this feature appears to have wholly escaped Dr. Morton’s attention, as he
merely enters it in his catalogue as a “cast of the skull of a young Greek: Prof.
Retzius,” I should be tempted to suppose it had been purposely sent to him to
illustrate the phenomena of unsymmetrical development, and of the influence of
undesigned artificial causes on other crania besides those of the New World.

The : strongly marked deformation of many flattened Indian skulls so clearly
separates them as a class from all others, including those modified by partial or
undesigned compression, as in the British examples referred to, that the very
familiarity with the former is calculated to lead the American craniologist to
overlook the artificial source of slighter changes. Nevertheless, Dr. Morton
was not unobservant of such indications of the frequent dissimilarity between
opposite sides of the skull, nor did he entertain any doubt as to its cause when
ocemring as the accompaniment of other artificial changes, though he entirely
overlooked its more general prevalence. When first noticing the probable origin
of the flattened occiput of certain British skulls, I drew attention to the fact that
he had already recognized undesigned artificial compression as one source of
abnormal cranial conformation, and that he accompanied its demonstration with a
reference to the predominant unsymmetrical form in allsuch skulls. ‘This irregu-
larity,’ he observes, ‘chiefly consists in the greater projection of the occiput to one
side than the other,” and ‘is not to be attributed to the intentional application
of mechanical force.” Such want of uniformity in the two sides of the head is

280 PHYSICAL ETHNOLOGY.

much more strongly marked in the Flathead skulls, which have been subjected
to great: compression. It is clearly traceable to the difficulty of subjecting the
living and growing head to a perfectly uniform and equable pressure, aad to the
cerebral mass foremg the skull to expand with it in the direction of least resist-
ance. Hence the unsymmetrical form accompanying the vertical occiput in the
Lesmurdie and Juniper Green skul's. and, as I conceive, also in the Greek skull
of Retzius. The study of the latter skull-form has tended to confirm my belief
that the extreme abbreviated proportions of many naturally brachycephalie
crania are due to artificial causes. Wherever a very noticeable inequality exists
between the two sides of a skull, it may be ascribed with much probability to
the indirect results of desigued or accidental compression in infaney; and by its
frequent occurrence in any uniform aspect, may, quite as much as the flattened
occiput, furnish a clue to customs or modes of nurture among the people to whom
it pertains.

But besides the practices referred to, many minor causes tend to produce
peculiar forms and irregularity of development in the human head. Among
those, I have become familiar with a number of cases, where, owing to the
inability of the mother to suckle her child at one breast, the constant pressure
in one direction which this led to has produced a marked flattening on the cor-
responding side of the child’s head, with tumid expansion on the other. The
mere practice of the nurse constantly carrying the child on one arm, or syste-
matically laying it to sleep on one side, must have a tendency to produce similar
results ; for the bones of the infant’s head during the first year are exceedingly
soft and pliable, and, as the processes pursued by the Flathead Indians show,
may be moulded into almost any form by moderate pressure. The normal
human head may be assumed to present a perfect correspondence in its two
hemispheres; but very slight investigation will suffice to convince the observer
that few living examples satisfy the requirements of such a theoretical standard.
Not only is inequality in the two sides of frequent occurrence, but a perfectly
symmetrical head is the exception rather than the rule. ‘The plastic condition
of the cranial bones in infancy also renders the infant head liable to many un-
designed changes of form. ‘he obstetric practitioner is also familiar with the
extreme deviations from the normal or congenital form of head produced at birth,
where instruments have to be used; but which, from the plastie condition
ot the bones, speedily disappear, or are greatly modified by the growth of the
brain.

In connexion with this branch of the subject the following observations of Sir
Robert H. Schomburgk on the Maopityans, or Frog Indians, of British Guiana,
are well worthy of consideration. ‘They are the remnant of a nearly extinet
tribe. Of their cranial formation he remarks: ‘The flatness of the head, and
consequently the long face and short circumference, is peculiar to the tribe. I
have not been able to learn, upon the most minute inquiries, that the form is
given to the head by artificial means. The occiput of the men is high, and
almost perpendicular above the front; the frontal bone is small with regard to
extent, and in no comparison to the face below the eyes; the cheek bones are
harsh and prominent; but the most remarkable part of the head is the great
extent between ear and ear, if measured from the upper part of that organ, and
the line continued above the eyebrows to the commencement of the other ear.
It surpasses the measurement of other Indians generally by an inch or two.”
Notwithstanding the inability of this intelligent and observant traveller to recover
any traces of ariificial causes influencing so remarkable a form of head, we might
still be tempted to refer it to a source so familiar to the American craniclogist.
But three days after his arrival at the settlement, one of the women, a Maopi-
tyan, but the wife of a ‘Taruma—a neighboring tribe characterized by an un-
usually small and differently formed head—was delivered of a male child. Sir
Robert Schomburgk states: ‘The Indians invited me to see the infant, and

PHYSICAL ETHNOLOGY. 281

accordingly, provided with some suitable presents, I went. The newborn child
had all the characterictics of the mother’s tribe. It was not quite an hour old
when I saw it, and the flatness of its head as compared with the heads of other
tribes, was very remarkable.”* Such a narrative, resting as it does on unques-
tionable authority, shows the danger of error in referring all seemingly abnormal
cranial forms to artificial causes, and might almost tempt the theorist to recur to
the idea entertained by Hippocrates, relative to the Macrocephali of the Crimea,
that long heads ultimately became so natural among them that the favorite form
was perpetuated by ordinary generation. 'To have rendered the observations
complete, however, it would have been desirable to have had a further report on
the shape of the infant’s head some time after birth, so as to determine if it were
entirely due to the inherited typical head-form of the mother’s tribe, and not to
an unusual amount of compression incident to the circumstances of its birth.

When the pressure is not, as in the processes operating at birth, temporary,
but continuous or repeatedly applied in the same direction, at brief intervals, as
in nursing entirely at one breast,a want of uniformity is certain to result. The
dissimilarity in the two sides of the head is strongly marked in Flathead skulls
which have been subjected to great compression. This is clearly trrceable to the
difficulty of subjecting the living and growing head to a perfectly uniform and
equable pressure, and to the cerebral mass forcing the skull to expand with it
in the direction of least resistance. Hence the unsymmetrical form accompany-
ing the vertical occiput in the Lesmurdie and Juniper Green skulls. Wherever
therefore a very noticeable inequality exists between the two sides of a skull,
it may be traced with much probability to designed or accidental compression in
infancy, and by its frequent occurrence in any uniform aspect, may, quite as
much as the flattened occiput, furnish a clue to customs or modes of nurture
among the people to whom it pertains.

Irregular head-forms are so much concealed by the hair and head-dress that
it is only in very marked cases they attract the attention of ordinary observers.
But, as I have shown in former publications on this subject,t they are familiar
to hat-makers, and frequently include extremely unsymmetrical developments
and great inequality in opposite sides of the head. A modern skull in the
collection of Dr. Struthers, of Edinburg, exhibits an interesting combination
of the proportions of the ancient brachycephalic type, with unsymmetrical con-
formation. It measures 7.5 longitudinal diameter, 6.5 parietal diameter, 21.4
horizontal circumference, and its greatest breadth is so near the occiput that the
truncated form observable in the vertical view of many ancient British crania is
produced in its most marked character by the abrupt flattening immediately
behind the parietal protuberances, accompanied with inequality in the two sides
of the head. It was obtained from a grave-digger in Dundee, who stated it to
be that of a middle-aged female whom he had known during life. There was
nothing particular about her mental development.

The novel forms thus occurring in modern heads, though chiefly traceable, as
I believe, to artificial causes, are not the result of design. But the same is true
of the prevalent vertical and obliquely flattened occiput of many ancient and
modern American crania, as well as of the British brachycephalie class already
described. Nor are such changes of the natural form necessarily limited to
skulls of short longitudinal diameter, in which this typical @haracteristic is
exaggerated by the pressure of the cradle-board in infancy. Now that this
source of modification begins to receive general recognition among craniologists,
its influence is assumed as a probable source of the most diverse aberrant forms.
Dr. 'Thurnam, when referring to two skulls of different shapes, recovered from
the same group of British barrows, of ‘(a somewhat late though pre-Roman

*Journal of the Royal Geographical Society, vol. xvi, pp. 53, 57.
} Prehistoric Man, vol. ii, p. 312 ; Canadian Journal, vol. vii, 414.

282 PHYSICAL ETHNOLOGY.

period,”’ on Roundway hill, North Wiltshire, thus indicates their contrasting
characteristics, and suggests the probable source of such divergence from the
supposed British type: “The general form of the cranium (pl. 43) differs greatly
from that from the adjoining barrow, (pl. 42.) That approaches an acroceph-
alic, this a platycephalic form; that is eminently brachycephalic, this more
nearly of a dolichocephalic character. As the eye at once detects, the difference
is much greater than would be inferred from a mere comparison of the measure-
ments. ‘The respective peculiarities of form in the two skulls may possibly be
explained by supposing that both have been subject to artificial deformation,
though of a different kind—the one appearing to have been flattened on the
occiput, the other showing a depression immediately behind the coronal suture,
over the parietal bones, which seems to indicate that this part of the skull was
subject to some habitual pressure and constriction, perhaps from the use of a
bandage or ligature tightly bound across the head and tied under the chin, such
as to this day is employed in certain parts of the west of France, producing
that form of distortion named, by Dr. Gosse, the sincipital, or ¢éte bilobée.’’*
The gradual recognition of this secondary source of undesigned artificial

n " . ° oo
changes in the form of the skull may be traced through various works, from

the vague perception of its occasional influence on the occipital form of American
erania, indicated by Dr. Morton, to the full appreciation of its varied effects in
the production of the most diverse exaggerations of normal or abnormal shapes,
in the later decades of the Crania Britannica. Dr. J. B. Davis devotes a
chapter in the first decade to the subject of “Distortions of the human skull,”
in which he minutely discusses the influence of artificial causes in modifying and
transforming its natural shape in a wonderful and frequently very fantastic
manner. Dut the only class of changes which attracts his attention, in addition
to those expressly resulting from design, are the examples of the fourth class,
where the deformation is clearly traceable to posthumous compression. But
during the progress of the work the attention of various observers was directed
to the secondary sources of change of form, and especially to such as may be
ascribed to the use of the cradle-board, or some corresponding nursing usage.
In the fifth decade of the Crania Britannica accordingly may be traced very
clearly the influence of the full recognition of such causes in modifying the
views of its joint authors as to the significance of certain peculiar skull-forms.
An extremely brachycephalic skull of a youth, obtained from a barrow on
Ballard Down, Isle of Purbeck, is described as unsymmetrical, and as affording
“tolerably clear evidence that this form, if not always produced, was at least
liable to be exaggerated by an artificial flattening of the occiput, such as is
practiced by many American and Polynesian tribes.’’t In the same decade
another skull of the type, most dissimilar to this, is described and illustrated.
It was recovered in fragments from the remarkable chambered barrow at West
Kennet, Wiltshire ; and its most characteristic features are thus defined by Dr.
Thurnam: “It is decidedly dolichocephalic, narrow, and very flat at the sides,
and realizes more nearly than any we have yet had to figure the kumbecephalic
or boai-shaped form deseribed by Dr. D. Wilson. 'The frontal region is narrow,
moderately arched, and elevated at the vertex, but slopes away on each side.
The parietal region is long, and marked by a prominent ridge or carina in the
line of the sagittal suture, which is far advanced towards obliteration, whilst
the other sutures are quite as perfect as usual. The oeciput is full and promi-
nent; the supra-cccipital ridges only moderately marked. There is a deep
digastric groove, and a slight parocipital process on each side. The external
auditory openings are somewhat behind the middle of the skull, and very much
behind a vertical line drawn from the junction of the coronal and sagittal

* Crania Britannica, Dec. v, pl. 43.
{ Crania Britannica, Dec. v, pl. 45.

PHYSICAL ETHNOLOGY. 283

sutures.” Its extreme length and breadth are 7.7 and 5.1, and an inequality in
the development of the two sides is obvious in the vertical view. As the
brachycephalic skull recalls certain American and Polynesian forms, so such
examples of the opposite type suggest the narrow and elongated skulls of the

«Australians and Esquimaux; and he thus proceeds: “'The Ballard Down skull
bears marks of artificial flattening of the occiput; this calls to mind the artificial
lateral flattening of the skull characteristic of the ancient people called Macro-
cephali, or long heads, of whom Hippocrates tells us that ‘while the head of
the child is still tender, they fashion it with their hands, and constrain it to
assume a lengthened shape by applying bandages and other suitable contrivances,
whereby the spherical form of the head is destroyed, and it is made to increase
in length.’ This mode of distortion is called by Dr. Gosse the temporo-parietal
or ‘ ¢éte aplatie sur-les cétés.’ It appears to have been practiced by various
people, both of the ancient and modern world, and in Europe as well as the
east. The so-called Moors, or Arabs of North Africa, affected this form of
skull; and even in modern times the women of Belgium and Hamburg are both
described as compressing the heads of their infants into an elongate form. Our
own observations lead at least to a presumption that this form of artificial dis-
tortion may have been practiced by certain primeval British tribes, particularly
those who buried their distinguished dead in long chambered tumuli.”

Tn connexion with this class of head-forms, as the result of compression, Dr.
Thurnam draws attention to the obliteration of the sagittal suture in the elongated
skull. I have noted this in many Flathead crania, and shall recur to the subject
in referring to those in the Washington and Philadelphia collections. If the
artificial forms result from compression, the flattened oeciput and artificially
abbreviated skull should show a tendency to ossification and obliteration of the
coronal and the lambdoidal sutures; while in the elongated skull the sagittal
suture will be the one affected, as is the case in one figured and described by
Blumenbach, under the name of “ Asiatic Macrocephali.”’ But in all
cases of an artificial change of form, the natural proportions necessarily
exercise some influence on the result; and Dr. Thurnam, accordingly,
when referring to the obliteration of the sagittal suture as a result of the
artificial elongation of the West Kennet skull, expresses his belief that this
“has been produced by pressure or manipulations of the sides of the head
in infancy, by which it was sought to favor the development of a lengthened
form of skull; to which, however, there was probably, in the present instance,
at least, a natural and inherent tendency.” It is perhaps worthy of note here,
that a long narrow head has been observed as one of the characteristic features
of Berber tribes of North Africa. Mr. J. Homer Dixon, who resided for some
time at Algiers, and had repeated opportunities of visiting and closely observing
the neighboring tribes, describes them to me as distinguished by their prominent,
arched nose, with wide nostrils ; large mouth but thin lips, and an unusual length
of head. ‘The constancy of the long head-form particularly struck him, but I
could not learn from him of any nursing practice calculated to originate or
increase such a development.

From the various authorities and illustrative examples referred to, it is obvious
that a class of variations of the form of the human skull, which becomes more
comprehensive as attention is directed to it, is wholly independent of congenital
transmitted characteristics. Kumbecephalic, acrocephalic, and platycephalic,
unsymmetrical, truncated, or elongated heads, may be so common as apparently
to furnish distinctive ethnical forms, and yet, after all, each may be traceable to
artificial causes, arising from an adherence to certain customs and usages in the
nursery. It is in this direction, I conceive, that the importance of the truths
resulting from the recognition of artificial causes affecting the forms of British
brachycephalic or other crania chiefly lies. The contents of early British cists
and barrows prove that the race with which they originated was a rude people,

284 PHYSICAL ETHNOLOGY.

ignorant for the most part of the very knowledge of metals, or at best in the
earliest rudimentary stage of metallurgic arts. They were, in fact, in as unciv-
ilized a condition as the rudest forest Indians of America. To prove, therefore,
that, like the Red Indian squaw, the British allophylian or Celtic mother formed
the cradle for her babe of a flat board, to which she bound it, for safety and*
facility of nursing, in the vicissitudes of her nomade life—though interesting,
like every other recovered glimpse of a long forgotten past—is not in itself a
discovery of much significance. But it reminds us how essentially man, even
in the most degraded state of wandering savage life, differs from all other
animals. ‘The germs of an artificial life are there. External appliances, and
the conditions which we designate as domestication in the lower animals, appear
to be inseparable from him. ‘The most untutored nomades subject their offspring
to many artificial influences, such as have no analogy among the marvellous
instinctive operations of the lower animals. It is even not unworthy of notice
that man is the only animal to whom a supine position is natural for repose; and
with him, more than any other animal, the head, when recumbent, invariably
assumes a position which throws the greatest pressure on the brain case, and
not on the malar or maxillary bones.

It thus appears that the study of cranial forms for ethnological purposes is
beset with many complex elements; and now that the operation of undesigned
artificial influences begins to receive an adequate recognition, there is a danger
that too much may be ascribed to them, and that the ethnical significance of
congenital forms, and their traces even in the modified crania of different types,
may be slighted or wholly ignored. Such was undoubtedly the effect on Dr.
Morton’s mind from his familiarity with the results of artificial deformation on
American crania, coupled, perhaps, with the seductive influences of a favorite
hypothesis. In his latest recorded opinions, when commenting on some of the
abnormal forms of Peruvian crania, he remarks: “I at first found it difficult to
conceive that the original rounded skull of the Indian could be changed into this
fantastic form, and was led to suppose that the latter was an artificial elongation
of a head remarkable for its length and narrowness. I even supposed that the
long-headed Peruvians were a more ancient people than the Inea tribes, and
distinguished from them by their cranial configuration. In this opinion I was
mistaken. Abundant means of observation and comparison have since con-
vinced me that all these variously-formed heads were originally of the same
shape, which is characteristic of the aboriginal race from Cape Horn to Canada,
and that art alone has caused the diversities among them.”* Itis obvious, how-
ever, that without running to the extreme of Dr. Morton, who denied, for the
American continent, at least, the existence of any true dolichocephalic crania,
or, indeed, any essential variation from one assumed typical form, it becomes an
important point for the craniologist to determine, if possible, to what extent
certain characteristic diversities may be relied upon as the inherited features of
a tribe or race, or whether they are not the mere result of artificial causes origi-
nating in long perpetuated national customs and nursery usages. If the latter
is indeed the case, then they pertain to the materials of archeological rather
than of ethnological deduction, and can no longer be employed as elements of
ethnical classification.

The idea that the peculiar forms of certain ancient European skuils is trace-
able to the use of the eradle-board, or other nursing usages, is rapidly gaining
ground, with extended observations. My own ideas, formed at an earlier date,
were first published in 1857,t but it now appears that the same idea had occurred
to Dr. L. A. Gosse, and received by him a wider application. In his “ Essai
sur les Déformations artificielles du Crane,’”’ he has not only illustrated the

* Physical Type of the American Indian, p. 326.
+ Edin. Philosoph. Jour., N. S., Vol. VU, p. 25; Canadian Journal, Vol. II, p. 426.

PHYSICAL ETHNOLOGY. 285

general subject of artificial causes as a means of accounting for abnormal cranial
forms, but he thus incidentally notices the peculiarity referred to in Scottish and
Scandinavian skulls, and traces it to the same probable source of the cradle-
board. His remarks are: “ Passant dans l’ancien continent, ne tardons-nous
pas 4 reconnaitre que ce bereeau plat et solide y a produit des effets analogues.
Les anciens habitans de la Seandinavie et de la Calédonie devaient s’en servir.
si on en juge par la forme de leurs crines.”* Dr. Gosse also adds: “ Vésale
( Opera, lib. I, cap. v, § 25) nous apprend que la deformation occipitale s’obser-
vait méme chez les Germains de son époque: ‘German? vero compresso ple-
rumgque occipite et lato capite spectantur, quod puert in cunis dorso semper in-
cumbant, ac manibus fere eitra fasciarum usum, cunarum lateribus utrinque
alliguntur” De meme qu’en Amerique, cette pratique, en Allemagne, devait
étre commune aux deux sexes.’”’

More recently Dr. J. Barnard Davis has illustrated the same subject, both in
the later decades of the Crania Britannica and in a memoir in the Natural
Mistory Review for July, 1862, entitled “ Notes on the Distortions which pre-
sent themselves in the Crania of the Ancient Britons.”

Whilst the error of an undue estimate of the extent of such deforming and
reforming influences must be guarded against, it is obvious that they will hence-
forth require to be taken into account in every attempt to determine ethnical
classification by means of physical conformation. Every scheme of the crani-
ologist for systematizing ethnical variations of cranial configuration, and every
process of induction pursued by the ethnologist from such data, proceed on the
assumption that such varieties in the form of cranium are constant within cer-
tain determinate limits, and originate in like natural causes with the features by
which we distinguish one nation from another. By like means the comparative
anatomist discriminates between the remains of the Bos primigenius, the Bos
longifrons, and other kindred animal remains, frequently found alongside the
human skeleton, in the barrow; and by a similar crucial comparison the erani-
ologist aims at classifying the crania of the ancient Briton, Roman, Saxon, and
Scandinavian, apart trom any aid derived from the evidence of accompanying
works of art. But if it be no longer disputable that the human head is liable
to modification from external causes, so that one skull may have been subjected
to lateral compression, resulting in the elongation and narrowing of its form,
while another under the influence of occipital pressure may exhibit a consequent
abbreviation in its length, accompanied by parietal expansion, it becomes indis-
pensable to determine some data whereby to eliminate this perturbing element
before we can ascertain the actual significance of national skull-forms. If, for
example, as appears to be the case, the crania from British graves of Roman
times reveal a different form from that of the modern Celtic Briton, the cause
may be an intermixture of races, like that which is clearly traceable among the
mingled descendants of Celtic and Scandinavian blood in the north of Scotland;
but it may also be in part, or wholly. the mere result of a change of national
customs following naturally on conquest, civilization, and the abandonment of
Paganism for Christianity.

It is, is this respect, that the artificial causes tending to alter the natural con-
formation of the human head invite our special study. ‘They appear at present
purely as disturbing elements in the employment of craniological tests of classi-
fication. It is far from improbable, however, that when fully understood they
may greatly extend our means of classification ; so that when we have traced to
such causes certain changes in form, in which modern races are known to differ
from their ethnical precursors, we shall be able to turn the present element of
disturbance to account, as an additional confirmation of truths established by
inductive craniology. Certain it is, however, whatever value may attach to

* Essai sur les Déformations artificielles du Crane,” p. 74, Dr. L. A. Gosse, 1855.

286 PHYSICAL ETHNOLOGY.

/
the systematizing of such artificial forms, that they are of frequent occurrence,

apart altogether from such configuration as is clearly referable to the application
of mechanical pressure in infancy with that express object in view ; or, again, as is
no less obviously the result of posthumous compression. But, though the de-
forming processes designedly practiced among ancient and modern savage nations
lie beyond the direct purpose of the present inquiry, they are calculated to
throw important light on the approximate results of undesigned compression and
arrested development.

Among the Flathead Indian tribes of Oregon and Columbia river, where mal-
formation of the skull is purposely aimed at, the infant’s head is tightly bound
in a fixed position, and maintained under a continuous pressure for months.
But it is a mistake to suppose that in the ordinary use of the cradle-board the
Indian pappoose is subject to any such extreme restraint. The objects in view
are facility of nursing and transport, and perfect safety for the child. But
those being secured, it is nurtured with a tenderness.of maternal instinct sur-
passing that of many savage nations. The infant is invariably laid on its back,
but the head rests on a pillow or mat of moss or frayed bark, and is not further
restrained in a fixed position than necessarily results from the posture in which
the body is retained by the bandages securing it in the cradle. ‘This fact I have
sadsfied myself of from repeated observations. But the consequence necessarily
is, that the soft and pliant bones of the infant’s head are subjected to a slight
but constant pressure on the occiput during the whole protracted period of nurs-
ing, when they are peculiarly sensitive to external influences. Experiments
have shown that at that period the bones specially affected by the action of the
cradle-board are not only susceptible of changes, but liable to morbid affections,
dependent on the nature of the infant’s food. Lehmann supposes the cranio-
tabes of Elsiisser to be a form of rachitis which affects the occipital and parietal
bones during the period of suckling; and Schlossberger ascertained by a series
of analyses of such bones that the 63 per cent. of mineral constituents found in
the normal occipital bones of healthy children during the first year diminished
to 51 per cent. in the thickened and spongy bone.* ‘The fluctuations in propor-
tion of the mineral constituents of bones are considerable, and vary in the dif-
ferent bones, but in the osseous tissue they may be stated at 67 to 70 per cent.
It is obvious, therefore, that, under the peculiar physio'ogical condition of the
cranial bones during the period of nursing, such constant mechanical action as
the occipital region of the Indian pappoose is subjected to must be productive
of permanent change. The child is not removed from the cradle board when
suckling and is not therefore liable to any counteracting lateral pressure against
its mother’s breast. ‘rifling as it may appear, it is not without interest to have
the fact brought under our notice by the disclosures. of ancient barrows and
cists, that the same practice of nursing the child, and carrying it about bound
to a flat cradle-board, prevailed in Britain and the north of Europe long before the
first notices of written history reveal the presence of man beyond the Baltic or
the English channel, and that, in all probability, the same custom prevailed con-
tinuously from the shores of the German Ocean to Behring’s Straits. All the
effects of such a universally prevalent practice, operating to produce uniform
results on the form of the skull and brain, are scarcely yet fully estimated; but
that it has affected the form of the head wherever it has been practiced I enter-
tain no doubt. One effect of the continuous pressure on the infant skull must
be to bring the edges of the bones together, and thereby to retard or arrest the
growth of the bone in certain directions. Where this leads to ossification at a
very early period, its tendency must be to Hmit the direction in which the fur-
ther expansion of the brain takes place, and so still further to affect the perma-
nent shape of the head. ‘The tendency of the pressure to produce some of the

*Schlossberger, Arch., f. phys. Heilk. Lehmann, Physiol. Chem., Vol. III, p. 28.

PHYSICAL ETHNOLOGY. 287

«

results here ascribed to it is proved by the premature ossification of sutures in
many of the artificially deformed American crania.

Among the numerous objects of ethnological interest brought home by the
United States Exploring Expedition, and now in the possession of the Smith-
sonian Institution, is a collection of thirty-four Flathead skulls. These I have
examined with minute care. Some of them exhibit the most diverse forms of
distortion, with the forehead sloping away at an abrupt angle from the eye-
brow, or flattened into a dise, so as to present in front the appearance of a hydro-
cephalous head, and in profile the side of a narrow wedge. Many of them are
also characterized by wormian bones and other abnormal formations at the
sutures, and the distinct definition of a true supra-occipital bone is repeatedly
apparent. In the majority of them the premature ossification, and the ocea-
sional entire obliteration of sutures, the gaping of others, and even traces of
fracture, or false sutures, may be observed.

It is marvellous to sce the extraordinary amount of distortion to which the
skull and brain may be subjected without seemingly affecting either health or
intellect. The coveted deformity is produced partly by actual compression, and
partly by the growth of the brain and skull being thereby limited to certain
directions. Hale, the ethnographer of the Exploring Expedition, after de-
scribing the process as practiced among the Chinooks, remarks: ‘“ ‘The appear-
ance of the child when just released from this confinement is truly hideous.
The transverse diameter of the head above the ears is nearly twice as great as
the longitudinal, from the forehead to the occiput. ‘The eyes, which are natu-
rally deep-set, become protruding and appear as if squeezed partially out of the
head.”* Mr. Paul Kane, in describing to me the same appearance, as witnessed
by him on the Columbia river, compared the eyes to those of a mouse strangled
in atrap. The appearance is little less singular for some time after the chiid
has been freed from the constricting bandages, as shown in an engraving from
one of Mr. Kane’s sketches of a Chinook child seen by him at Fort Astoria.t

In after years the brain, as it increases, partially recovers its shape; and in
some of the deformed adult skulls one suture gapes, while all the rest are ossi-
fied ; and occasionally a fracture or false suture remains open. An adult skull
of the same extremely deformed shape, among those brought home by the Ex-
ploring Expedition, illustrates the great extent to which the brain may be sub-
jected to compression and malformation without affecting the intellect. It is ,
that of a Nisqually chief, procured from his canoe-bier in Washington 'Terci-
tory. (No. 4549.) The internal capacity, and consequent volume of brain, is
95 cubic inches. The head is compressed into a flattened disc, with the fore-
head receding in a straight line from the nasal suture to the crown of the head,
while the lambdoidal suture is on the same plane with the foramen magnum.
The sutures are nearly all completely ossified, and the teeth ground quite flat,
as is common with many of the tribes in the same region, and especially with
the Walla-Walla Indians on the Columbia river, who live chiefly on salmon,
dried in the sun, and invariably impregnated with the sand which abounds in
the barren waste they occupy. I assume the unimpaired intellect of the Nis-
qually chief from his rank. The Flathead tribes are in the constant habit of
making slaves of the Roundheaded Indians; but no slave is allowed to flatten
or otherwise modify the form of her child’s head, that being the badge of Flat-
head aristocracy. As this has been systematically pursued ever since the tribes
of the Pacific coast were brought under the notice of Europeans, it is obvious
that if such superinduced deformity developed any general tendency to cerebral
disease, or materially affected the intellect, the result would be apparent in the
degeneracy or extirpation of the Flathead tribes. But so far is this from bemg

* Ethnography of the U. 8S. Exploring Expedition, p. 216.
t Prehistoric Man, Vol. If, p. 320.

288 PHYSICAL ETHNOLOGY,

2

the case, that they are described by traders and voyagers as acute and intelli-
gent. They are, moreover, an object of dread to neighboring tribes who retain
the normal form of head, and they look on them with contempt as thus bearing
the hereditary badge of ‘slaves.

The child born to such strange honors is laid, soon after its birth, upon the eradle-
board, an oblong piece of wood, sometimes slightly hollowed, and with a cross-
board projecting beyond the head to protect it from injury. A small pad of
leather, stuffed with moss or frayed cedar-bark, is placed on the forehead and
tightly fastened on either side to the board; and this is rarely loosened until
its final removal before the end of the first year. The skull has then received
a form which is only slightly modified during the subsequent growth of the
brain. But the very same kind of eradle is in use among all the Indian tribes.
It is, indeed, varied as to its ornamental adjuncts and non-essential details, but
practically it resolves itself, in every case, into a straight board to which the
infant is bound; and as it is retained in a recumbent position, the pressure
of its own weight during the period when, as has been shown, the occipital and
parietal bones are peculiarly soft and compressible, is thus made to act constantly
in one direction. ‘This I assume to have been the cause of the vertical or other-
wise flattened occiput in the ancient British brachycephalie crania. The same
cause must tend to increase the characteristic shortness in the longitudinal
diameter, to produce the premature ossification of certain sutures, and to shorten
the zygoma, with probably, also, some tendency to make the arch bulge out in
its effort at subsequent full growth, and so to widen the face.

Fashion regulates to some extent the special form of head aimed at among
the various Flathead tribes. Some compress the whole brain into a flattened dise
which presents an enormous forehead in full face; others run to the opposite
extreme, and force it into an abrupt slope immediately above the eyebrows, so
as to give an idiotic look to the seemingly brainless face. Individual caprice,
and probably, also, clumsy manipulation, combine frequently to produce a
shapeless deformity of skull, in which the opposite sides present no trace of
correspondence, and every vestige of ethnical character is effaced. Among the
Newatees, a tribe on the north end of Vancouver’s island, the head is foreed
into a conical shape, by means of a cord of deer’s-skin padded with the inner
bark of the cedar tree, frayed into the consistency of soft tow. This forms a
cord about the thickness of a man’s thumb, which is wound round the infant’s
head, and gradually compresses it into a tapering cone. Commander Mayne,
in his narrative of his visit to Columbia and Vancouver island, gives a sketch
of an Indian girl, and adds in reference to it: ‘Those who have only seen cer-
tain tribes may be inclined to think the sketch exaggerated, but it was really
drawn from measurement, and she was found to have eighteen inches of flesh
from her eyes to the top of her head.” From the extraordinary amount of de-
formity which I have seen produced by such means, it would be unwise to
reject any narrative of an intelligent eye-witness relative to extreme examples
of such abnormal heads. I should be inclined, however, to suspect that in
the case of the gil drawn by Commander Mayne, he was deceived by her
mode of dressing her hair. I have engvaved in my “ Prehistoric Man’’* the
head of a Newatee chief of the same conical form, and with the hair gathered
into a knot on the top of the head. The latter practice is in constant use for
increasing the apparent elevation of the favorite conoid head-form. In all such
cases the volume of brain appears to remain little, if at all, affected, and the
extreme proportions in length, breadth, or height of the skull must be limited
by the capacity of the brain, whatever be the fantastic shape it is made to
assume. In the case of the girl from Vancouver’s island, part of the extreme

* Prehistoric Man, Vol. I, p. 317.

PHYSICAL ETHNOLOGY. 289

height of her singularly formed head was probably an artificial pad over which
the hair was drawn.

Compared with such extreme deformation, the traces of artificial change on
the forms of British skulls are trifling. They are, however, all the more im-
portant from their liability to be confounded with true congenital forms, as in
the case of the flattened occiput. Dr. Davis has applied the term “ parieto-
occipital flatness,” where the results of artificial compression in certain British
skulls extend over the parietals with the upper portion of the occipital, and he
appears to regard this as something essentially distinct from the vertical occi-
put.* But it is a form of common occurrence in Indian skulls, and is in reality
the most inartificial of all the results of the undesigned pressure of the cradle-
board. This will be understood by a very simple experiment. If the observer
lie down on the floor, without a pillow, and then ascertain what part of the back
of the head touches the ground, he will find that it is the portion of the occiput
immediately above the lambdoidal suture, and not the occipital bone. When the
Indian mother places a sufficiently high pillow for her infant, the tendency of
the constant pressure will be to produce the vertical occiput; but where, as is
more frequently the case, the board has a mere cover of moss or soft leather,
then the result will be just such an oblique parietal flattening as is shown on a
British skull from the remaikable tumulus near Littleton Drew, Wiltshire.t

But there are other sources of modification of the human skull in infancy,
even more common than the cradle-board. More than one of the predominant
head-forms in Normandy and Belgium are now traced to artificial bandaging;
and by many apparently trifling and unheeded causes, consequent on national
customs, nursing usages, or the caprices of dress and fashion, the form of the
head may be modified in the nursery. The constant laying of the infant to
rest on its side, the pressure in the same direction in nursing it, along with the

oO
fashion of cap, hat, or wrappage, may all influence the shape of head among

civilized nations, and in certain cases tend as much to exaggerate the naturally
dolichocephalic skull as the Indian eradle-board increases the short diameter of
the opposite type. Such artificial cranial forms as that designated by M. Foville,
the Téte annulaire, may have predominated for many centuries throughout
certain rural districts of France, solely from the unreasoning conformity with
which the rustic nurse adhered to the traditional or prescriptive bandages to
which he ascribes that distortion. All experience shows that such usages are
among the least eradicable, and long survive the shock of revolutions that change
dynasties and efface more important national characteristics.

The effect, as we have already seen, which a constant familiarity with the
results of extreme artificial deformation on American crania produced on Dr.
Morton’s mind, was to lead him to ignore all distinctions of ethnical form, and
to retract his earlier idea that the elongated Peruvian crania were artificial ex-
ageerations of a head of great natural length. Originally he had adopted the
conclusion that the long-headed Pertvians were a more ancient people than
what he called the Inca tribes, and distinguished from them by their cranial
configuration; but this he abandoned at a later period, and assumed that every
skull found on the American continent, whatever might be the extreme variation
in opposite directions from his assumed typical form, had been naturally a short
globular skull, with low retreating forehead and vertical occiput. . On the fallacy
involved in such a conclusion it is unnecessary to make further comment, as the
evidence which appears to confute it has already been produced. But the dis-
closures of the essentially diverse types of skull in the ancient cemeteries of
Peru appear to me to present some highly interesting analogies to the discoy-
eries made in British barrows. ‘The repeated opportunities I have enjoyed of

* Nat. Hist. Review, July, 1862. Atheneum, Sept. 27. 1862, p. 402.
t Crania Britannica, Decade III, Plate 24.
19 C

290 PHYSICAL ETHNOLOGY.

examining the Mortonian and other American collections have satisfied me of
the occurrence of both dolichocephalic and brachycephalic crania, not only as the
characteristics of distinct tribes, but also among the contents of the same Peru-
vian cemeteries, not as examples of extreme latitudes of form in a common race,
but as the results of the admixture either of conquering and subject races, or
of distinct classes of nobles and serfs, most generally resulting from the pre-
dominance of conquerors. Among the Peruvians the elongated cranium per-
tained to the dominant race; and some of the results of later researches in
primitive British cemeteries, and especially the disclosures of the remarkable
class of chambered barrows, seem to point to an analogous condition of races.
That the Uley and West Kennet skulls may have been laterally compressed,
while the Codford barrow and other brachycephalic skulls have been affected
in the opposite direction, appears equally probable. But such artificial influences
only very partially account for the great diversity of type; and no such causes,
even if brought to bear in infancy, could possibly convert the one into the other
form.

But as the cranial forms, both of the Old and New World, betray evidences
of modification by such artificial means, so also we find in ancient Africa a
diverse form of head, to which art may have contributed, solely by leaving it
more than usually free from all extraneous influences. Such at least is a con-
clusion suggested to my mind from the examination of a considerable number
of Egyptian skulls. Among familiar relics of domestic usages of the ancient
Egyptians is the pillow designed for the neck, and not the head, to rest upon.
Such pillows are found of miniature sizes, indicating that the Egyptian passed
from earliest infaney without his head being subjected even to so slight a pres-
sure as the pillow, while he rested recumbent. The Egyptian skull is long,
with great breadth and fulness in the posterior region. In its prominent,
rounded parieto-occipital conformation, an equally striking contrast is presented
to the British brachycephalie skull, with truncated occiput, and to the opposite
extreme characteristic of the primitive dolichocephalic skull; though exceptional
examples are not rare. ‘This characteristic did not escape Dr. Morton’s observ-
ant eye; and is repeatedly indicated in the Crania Aigyptiaca under the designa-
tion, “tumid occiput.” It also appeared to me, after careful examination of the
fine collection formed by him, and now in the Academy of Natural Sciences of
Philadelphia, that the Egyptian crania are generally characterized by considera-
ble symmetrical uniformity: as was to be anticipated, if there is any truth in
the idea of undesigned artificial compression and deformation resulting from such
simple causes as accompany the mode of nurture in infancy.

The heads of the Fiji Islanders supply a means of testing the same cause,
operating on a brachycephalic form of cranium; as most of the islanders of the
Fiji group employ a neck pillow nearly similar to that of the ancient Egyptians,
and with the same purpose in view: that of preserving their elaborately dressed
hair from disshevelment. In their case, judging from an example in the collec-
tion of the Royal College of Surgeons of London, the occipital region is broad,
and presents in profile a uniform, rounded conformation passing almost imper-
ceptibly into the coronal region. Indeed, the broad, well-rounded occiput is
considered by the Fijians a great beauty. The bearing of this, however, in
relation to the present argument, depends on whether or not the Fiji neck-pillow
is used in infancy, of which I am uncertain. The necessity which suggests its
use at a later period does not then exist; but the prevalent use of any special
form of pillow for adults is likely to lead to its adoption from the fifst. In one
male Fiji skull brought home by the United States Exploring Expedition (No.
4581) the occiput exhibits the characteristic full, rounded form, with a large and
well-defined supra-occipital bone. But in another skull in the same collection—
that of Vendovi, Chict of Kantavu, who was taken prisoner by the United
States ship Peacock, in 1840, and died at New York in 1842—the occiput,

PHYSICAL ETHNOLOGY. 291

though full, is slightly vertical. The occipital development of the Fiji cranium
is the more interesting as we are now familiar with the fact that an artificially
flattened occiput is of common occurrence among the islanders of the Pacific
ocean. ‘In the Malay race,” says Dr. Pickering, “a more marked peculiarity,
and one very generally observable, is the elevated occiput, and its slight pro-
jection beyond the line of the neck. 'The Mongolian traits are heightened arti-
ficially in the Chinooks; but it is less generally known that a slight pressure is
often applied to the occiput by the Polynesians, in conformity with the Malay
standard.”* Dr. Nott, in describing the skull of a Kanaka of the Sandwich
Islands who died at the Marine Hospital at Mobile, mentions his being struck
by its singular occipital formation; but this he learned was due to an artificial
flattening which the islander had stated to his medical attendants in the hospital,
was habitually practiced in his family.t According to Dr. Davis, it is traceable
to so simple a source as the Kanaka mother’s habit of supporting the head of
her nursling in the palm of her hand.{ Whatever be the cause, the fact is now
well established. The occipital flattening is clearly defined in at least three of
the Kanaka skulls in the Mortonian collection: No. 1300, a male native of the
Sandwich Islands, aged about forty; No. 1308, apparently that of a woman,
from: the same locality; and in No. 695, a girl of Oahu, of probably twelve
years of age, which is markedly unsymmetrical, and with the flattening on the
left side of the parietal and occipital bones.. The Washington collection in-
cludes fourteen Kanaka skulls, besides others from various islands of the Pacific,
among which several examples of the same artificial formation occur: e. g., No.
4587, a large male skull, distorted and unsymmetrical; and No. 4367, (female ¢)
from an ancient cemetery at Wailuka, Mani, in which the flattened occiput is
very obvious.

The traces of purposed deformation of the head among the islanders of the
Pacific have an additional interest in their relation to one possible source of
South American population by oceanic migration, suggested by philological and
other independent evidence. But for our present purpose the peculiar value of
those modified skulls lies in the disclosures of influences operating alike unde-
signedly, and with a well-defined purpose, in producing the very same cranial
conformation among races occupying the British Islands in ages long anterior to
earliest history; and among the savage tribes of America and the simple island-
ers of the Pacific in the present day. They illustrate, with peculiar vividness,
the primitive condition of social life out of which the civilization of modern
Europe has been educed; and, while they pertain to more modern eras than the
traces of human art contemporaneous with the extinct mammals of the drift,
they revivify for us, with even clearer distinctness than the rude implements of
flint and stone found in early graves, the condition of the British Islanders of
prehistoric times.

PART Hi.

PEWish¢ AL« ELAN 'O0 L:0:G Ye

PRIMITIVE ART-TRACES.

The evidences of an assumed cranial and physical unity pervading the abo-
rigines of the American continent disappear upon a careful scrutiny, and the

** Pickering’s Races of Man, p. 45.
+Types of Mankind, p. 436.
t Crania Britannica, Dee. III, pl. 24, (4.)

292 PHYSICAL ETHNOLOGY.

like results follow when the same critical investigation is applied to other proofs
adduced in support of this attractive but unsubstantial theory. Dr. Morton, after
completing his elaborate and valuable illustrations of American craniology, intro-
duces an engraving of a mummy of a Muysea Indian of New Granada, and
adds: ‘As an additional evidence of the unity of race and species in the Amer-
ican nations, I shall now adduce the singular fact that, from Patagonia to Canada,
and from ocean to ocean, and equally in the civilized and uncivilized tribes, a
peculiar mode of placing the body in sepulture has been practiced from imme-
morial time. This peculiarity consists in the sitting posture.’* The author
accordingly proceeds to marshal his evidence in proof of the practice of such a
mode of interment among many separate and independent tribes; nor is it difii-
cult to do so, for it was a usage of greatly more extended recognition than his
theory of “unity of race and species” implies. It was a prevailing, though by
no means universal mode of sepulture among the tribes of the New World, as
it was among many of those of the Old, recorded by the pen of Herodotus, and
proved by sepulchral disclosures pertaining to still older eras. The British
cromlechs show that the very same custom was followed by their builders in
primitive times. ‘The ancient barrows of Scandinavia reveal the like fact, and
abundant evidence proves the existence of such sepulchral rites, in ancient or
modern times, in every quarter of the globe; so that, if the prevalence of a
peculiar mode of interment of the dead may be adduced as evidence of the unity
of race and species, it can only operate by reuniting the lost links which restore
to the red man his common share in the genealogy of the sons of Adam. But
ancient and modern discoveries also prove considerable diversity in the sepulchral
rites of all nations. ‘The skeleton has beaa found in a sitting posture in British
cromlechs, barrows, and graves, of dates to all appearance long prior to the era
of Roman invasion, and of others unquestionably subsequent to that of Saxon
immigration; but evidences are found of cremation and urn-burial, in equally
ancient times; of the recumbent skeleton under the cairn, and barrow, in the
stone cist, and in the rude sarcophagus hewn out of the solid trunk of the oak;
and in this, as in so many other respects, the British microcosm is but an epi-
tome of the great world. Norway, Denmark, Germany, and France all supply
similar evidences of varying rites; and ancient and modern customs of Asia
and Africa confirm the universality of the same. In the Tonga and other islands
of the Pacitic, as well as in the newer world of Australia, the custom of bury-
ing the dead in a sitting posture has been repeatedly noted; but it is not uni-
versal even among them; nor was it so in America, though affirmed by Dr.
Morton to be traceable throughout the northern and southern continents, and,
by its universality, to afford “collateral evidence of the aftiliation of all the
American nations.” So far is this from being the case that nearly every ancient
and modern sepulehral rite appears to have had its counterpart in the New
World; and in this, as in many other respects, its isolation from the older con-
tinents in affinities and corresponding characteristics, # not in actual intercourse,
disappears on more extended research. T’o follow out all the varied indications
of such analogy or parallelism would lead to a very extensive range of inquiry,
which I shall not now enter upon. But one seemingly trifling analogy, trace-
able in the correspondence of the rude weapons and implements of flint and
stone wrought and fashioned by the aborigines of America, with those recovered
from the ancient barrows of northern Europe, connects the early traces of
man in both hemispheres by means of arts which are acquiring a new and com-
prehensive significance.

The development of primitive archeology, by the labors of Thomsen and his
Danish fellow-laborers, into a systematic science, laid the foundations for that
novel and profoundly interesting inquiry which now tempts the ablest geologists

*Crania Americana, p. 244,

PHYSICAL ETHNOLOGY. 293

from the study of the paleosoic rocks to the recent sedimentary cave deposits
and the superficial drift. 'The investigations of: British archeologists, following
in the footsteps of their northern precursors, have now familiarized us with the
character of that primitive art so widely diffused throughout those ages embraced
within the European Srone Periop. ‘That age of stone derives its special
characteristic from the occurrence of numerous examples of arms and implements
of flint or stone, many of which are wrought with considerable skill and finished
with minute care. Others, however, are sufficiently rude and unshaped to illus-
trate the most artless efforts of primitive mechanical skill. These are formed
from flint nodules and pieces of rock by mere blows from another stone, guided,
in the case of the flint-workers, by a knowledge of the concoidal fracture of the
flint and the consequent facility of its reduction to long and narrow splinters,
readily convertible into wedges, chisels, knives, and lance or arrow heads. The
simplest implements of this class are frequently water-worn stones, partially
hewn, so as to reduce one end toa sharp or angular edge. But, while speci-
mens of such rudimentary art are not uncommon, many more are chipped into
symmetrical form with minute care and are ground fo a fine edge, or even
wrought into artistic forms and polished throughout the whole surface. 'T'o those
it has been customary with many to apply the epithet Ce/¢ic, and so to assume
their origin from that people who immediately preceded the Romans in the scenes
of their latest European conquests. ‘This, however, is rather an assumption
than any well-grounded induction; and, though revived by M. Boucher de
Perthes in his Antiguités Celtique et Antédiluviennes, (1849,) had been previ-
ously set aside by Thomsen, Worsaac, Nilsson, and other Scandinavian arche-
ologists, and, at the very time, was challenged in a communication submitted
by me to the ethnological section of the British Association, entitled: Ax Inquiry
into the Evidence of Primitive Races in Scotland prior to the Celta.* But that
which was a bold surmise in 1850 seems an insignificant and self-evident truism
in the light of the well-established facts, and cautious yet comprehensive induc-
tions, relative to the flint implements found in the same drift of England and
France alongside of bones of the Elephas primigenius, Rhinoceros tichor-
hinus, Equus fossilis, Felis spelea, Hyena spelea, and numerous other extinet
mammals. k

The facts connected with the discovery of works of human art associated
in undisturbed gravel with the fossil bones of extinct quadrupeds, or in corres-
ponding diluvial strata both of France and England, are now too well known
to need recapitulation. It is indeed a significant fact that some of them have
been long familiar to British antiquaries, though the true bearings of their dis-
covery are only now beginning to be recognized. So early as 1715, a weapon
of flint, six and a half inches long, and rudely chipped into the form of a spear-
head, was dug up at Black Mary’s, near Gray’s Inn Lane, London, along with
an elephant’s tooth, and apparently lying beside the entire skeleton of a fossil
elephant.t ‘This curious evidence of the remote presence of man in the most
populous centre of his modern civic settlements lay unheeded in the collections
of the British Museum for nearly a century and a half. Meanwhile, towards
the close of the eighteenth century, another remarkable discovery of the same
kind was made at Hoxne, in Suffolk, in gravel at a depth of twelve feet ina
stratified soil, and immediately underneath a horizontal bed of sand mixed with
shells of existing fresh-water and land mollusea, and with gigantic fossil bones.
An account of this discovery was commmnicated by Mr. John Frere to the
Society of Antiquaries of London jn 1797,t.and specimens of the flint imple-
ments were deposited in the society’s muscum, where they are still preserved.

It is interesting and highly satisfactory to know that not only had such facts

* British Association Report, 1850, p. 144,
tArcheologia, Vol. XXXVIII, p. 301.
t Ibid, Vol. XIII, p. 204.

294 PHYSICAL ETHNOLOGY.

been on record thus long before their significance was appreciated, but the rude
implements of the drift have been exhibited in the collections of the British
Museum and the Society of Antiquaries of London as the works of man; nor
was it till the corresponding discoveries in the French drift, and the minute
examination of the stratified gravel in which they were found, had led Rigollot,
Prestwich, Lyell, and other competent authorities to deduce evidence of a lapse
of many ages between the era of the fossil implements and that to which
Romano-Gaulish relics belong, that any one dreamt of questioning their human
origin. More recently similar implements have been found in the same diluvial
gravel and clay in which remains of the gigantic fossil mammals abound, in
Suffolk, Kent, Bedfordshire, and other post-pliocene deposits of the south of
England;* and not only is their artificial character undoubted, but the corres-
pondence between the drift implements of France and England is so close as to
be at once recognized by the workmen employed in. the excavations both at
Hoxne and Abbeville.

Such discoveries have naturally led to many startling speculations relative to
the apparent lapse of a vast period of time between the era of the drift race and
the earliest dates of authentic history, and it has been specially noted that while
the drift implements resemble in material those most frequently found in the
graves of northern Europe’s stone period, they present a striking contrast to the
small and well-finished implements chiefly pertaining to.such sepulchral deposits,
and seem to be the memorials of an age of ruder strength and still more infantile
skill. Such a conclusion, if fully borne out, is all the more important as it has
otherwise been noted as a highly interesting fact, that so general a correspondence
is traceable between the majority of the flint and stone weapons and implements
found in ancient European graves and those still manufactured by the aborigines
of the Pacific islands, and throughout the American continent, that they seem
like the products of the same mechanical instinct, repeating itself under similar
circumstances in the arts of savage man.

When Mr. Joseph Prestwich proceeded to Abbeville, in 1859, to investigate
the discoveries reported by M. Boucher de Perthes, he was accompanied by Mr.
John Evans, F. 5S. A., who has sinee communicated the results of their observa-
tions to the Society of Antiquariées.t He notes that, so faras hitherto observed,
the implements found in the drift are formed exclusively of flint, and these he
classifies, for convenience of further reference, under three heads :

1. Flint flakes, apparently intended for arrow-heads or knives.

2. Pointed weapons, some probably lance or spear heads.

3. Oval or almond-shaped implements presenting a cutting edge all round.

The objects first named most nearly resemble a numerous class found in
ancient sepulchral deposits, but they are produced by so simple a process, and
betray such partial traces of artificial modification, that even when their character
as works of art is indisputable, they bear so much resemblance to similar simple
natural forms as to be of little value as conclusive evidence of human design or
workmanship. But the case is altogether different with the two other classes;
and the opinion has been repeatedly expressed that they present little or no
analogy in form to any of the works described by Danish, British, or other
archxologists of Europe, as pertaining to the so-called Stone Period. Accord-
ingly, after having described the repeated discovery of flint flakes in the drift,
as in the sand and gravel near Abbeville, and in the corresponding formation at
Menchecourt, where Mr, Prestwich witnessed their exhumation, Mr. Evans
acknowledges the uncertainty pertaining to any argument based solely on such
evidence ; and still further specifies as an element rendering them valueless for

* Quarterly Journal of the Geological Society, Vol. XVII, p. 362.
+ On the Occurrence of Flint Implements in Undisturbed Beds of Gravel, Sand, and Clay.
By John Evans, F.S.A., F.G@.S. Archeologia, Vol. XXXVIIT, p. 280.

PHYSICAL ELHNOLOGY. 295

the purpose of those who are seeking for indications of man’s presence in such
localities at a period separated by vast ages from the earliest beginnings of
history, that, “though closely resembling the flakes of flint which have been
considered as affording evidence of man’s existence when found in ossiferous
caverns, this class is not of much ‘importance in the inquiry, because, granting
them to be of human work, there ts little by which to distinguish them from
similar implements of more recent date.” Of the artificial origin and peculiar
characteristics of the two other classes of implements no such doubt can be
entertained, and Mr. Evans accordingly proceeds to remark: “The case is dif:
ferent with the implements of the second class, those analogous in form to spear
or lance heads. Of these there are two varieties: the one with a rounded cut-
ting point, its general outline presenting a sort of parabolic curve,* the other
acutely pointed, with the sides curved slightly inward.t ‘These have received
from the workmen of St. Acheul the name of ‘langues de chat,’ from their
fancied resemblance to a cat’s tongue. The sides of both kinds are brought to
an edge by chipping, but are not so sharp as the point, and altogether these
weapons seem better adapted for piercing than for cutting. In lengih they vary
from about four inches to eight, or even nine inches. Both shapes are generally
more convex on one side than on the other, the convexity in some cases almost
amounting toa ridge. They are usually truncated at the base, and not unfre-
quently at that end show a portion of the original surface of the flint; in some
specimens the butt end is left very thick, as if to add impetus to any blow given
with the implement. The remarkable feature about them is their being adapted
only to cut or pierce at the pointed end, whereas in the ordinary form of stone
hatchet or celt the cutting edge is almost without exception at the broad end,
while the more pointed end seems intended for insertion into the handle or
socket. and the sides are generally rounded or flat, and not sharp.

“These spear-shaped weapons from the drift are, on the contrary, not at all
adapted for insertion into a socket, but are better ealculated to be tied to a shaft
or handle, with a stop or bracket behind their truncated end. Many of them,
indeed, seem to have been intended for use without any handle at all, the
rounded end of the flints from which they were formed having been left un-
chipped, and presenting a sort of natural handle. It is nearly useless to speculate
on the purposes to which they were applied, but, attached to poles, they would
prove formidable weapons for encounter with man, or the larger animals, either
in close conflict or thrown from a distance as darts.

“Tt has been suggested by M. de Perthes that some of them may have been
used merely as wedges for splitting wood, or, again, they may have been em-
ployed in grubbing for esculent roots, or tilling the ground, assuming that the
race who formed them was sufficiently advanced in civilization. This much, 1
think, may be said of them with certainty, that they are not analogous in form
with any of the ordinary implements of the so-called Stone Period.

“The same remark holds good with regard to the third class into which I
have divided these implements, viz., those with a cutting edge all round.¢ In
general contour they are usually oval, with one end more sharply curved than
the other, and occasionally coming to a sharp point, but there is a considerable
variety in their form, arising probably from defects in the flints from which they
were shaped; the ruling idea is, however, that of the oval, more or less pointed.
They are generally almost equally convex on the two sides, and in length vary
from two to eight or nine inches, though, for the most part, only about four or
five inches long. ‘The implements of this form appear to be most abundant in

*Archeologia, Vol. XX XVIII, pl. XV, No 1.
fib:d, pl. XV, No. 2.
tArchexologia, Vol. XX XVIII, pl. XV, No, 3.

296 PHYSICAL ETHNOLOGY.

the neighborhood of Abbeville, while those of the spear-shape prevail near
Amiens.”

Mr. Evans then points out that, among the implements discovered in Kent’s
Hole Cavern, there were some identical in form with the oval flints from Abbe-
vile; but he adds, “in character they do not resemble any of the ordinary
stone implements with which I am acquainted.”

It is obvious that a great, if not undue stress is laid on this dissimilarity
between the flint implements of the Drift and those of the more recent Stone
Period, with the assumed Celtic origin of its flint and stone manufactures. Nor
is this wonderful when the vast interval is considered which the geologist now
assumes to intervene between the production of the two classes of works. Sir
Charles Lyell, when addressing the Geological Section of the British Associa-
tion, remarked, with cautious yet suggestive force, in reference to the secular
phenomena indicated by the fluviatile gravel of Abbeville and Amiens :

“To explain these changes, I should infer considerable oscillations in the level
of the land in that part of I-rance ; slow movements of upheaval and subsidence,
deranging, but not wholly displacing, the course of the ancient river. Lastly,
the disappearance of the elephant, rhinocerus, and other genera of quadrupeds
now foreign to Europe, implies, in like manner, a vast lapse of ages, separating
the era in which the fossil implements were framed and that of the invasion of
Gaul by the Romans.”’

If man’s place in nature, and his true relation to the inferior orders of being

e stili undetermined, and the possibility of his development from the anthropoid
apes or others of the lower animals be admitted, then the first indices of animal
instinct passing into inventive mechanical skill will possess a peculiar significance.
Whether. moreover, we accept or reject the unwelcome theory of the structural
interval between the organization of man and the lower animals being the prac-
tical element of difference, and one sufficiently slight to require only an adequate
lapse of time for its being bridged over by secondary causes in constant operation
throughout the organic world; the comparison between the arts of ages so remote as
those of the Drift-l’olk, and the British Celt of the Roman period, or the Amer-
ican Indian of the nineteenth century cannot be devoid of interest. But America
also has her ancient, and possibly her drift flint-implements ; and as the analogies
between the works of her modern aborigines and those of the later European
Stone Period are obvious and remarkable, though separated by at least two
thousand years; a comparison of the oldest traces of human art on the two
hemispheres may involve very significant disclosures in reference to the general
question of the development of the mechanical and artistic faculties of man.

So impressed was my mind with the striking bearing of the supposed fact
reiterated by Prestwich, Evans, Lyell, and others, of the uniformity of char-
acter, amounting to specific typical forms, and of the massive rudeness of the
works of art of the drift, that it was with some sense of disappointment I re-
ceived a flint instrument believed to have been recovered from the American
drift, and found it fail in any correspondence with the post-pliocene manutac-
tures of Europe. The characteristics assigned to the former, separate their era,
to all appearance, by a diversity of the mental character expressed in them, as
works of human art, from the nearly uniform fint and stone implements of the
most ancient European stone period seemingly of historic times and existing
savage nations. ‘The confirmation it seems to lend to the idea of a condition
of human intellect more rudimentary than that of the rudest savage hitherto
known gives importance to the data on which such an influence rests. In the
summer of 1852 I learned from Mr. William Hay, architect, of a flint implement
recovered by a gold-digger from the drift near Pike’s peak, Kansas Territory,
and immediately instituted inquiries about it, not without some expectation of
findine; in it a repetition of one of the large typical forms of Abbeville or
Amiens. In this, however, I was disappointed. ‘The interesting object which

PHYSICAL ETHNOLOGY. 297

is now in my own possession is a broken knife or lance-head, measuring in its
present imperfect condition only 2% inches. I was placed in communication with
the discoverer by Mr. Hay, in whose employment he had formerly been; and
on my applying to him for information as to the precise circumstances under
which the flint implement had been discovered, he presented it to me, along with
the desired statement. Mr. P. A. Scott is an intelligent Canadian, formerly in
business as a carpenter at Cobourg, Upper Canada, who, in 1850, joined a party
about to start on an expedition to the gold diggings; and while engaged in the
search for gold at the Grinnell Leads, in Kansa# Territory, he found the imperfect
flint implement, figured here, the size
of the original, at a depth of upward
of fourteen feet from the surface.
The spot where this discovery was
made is in the Blue Range of the
Rocky mountains, in an alluvial bot-
tam, and distant several hundred feet
from a small stream called Clear creek.
A shaft was sunk, passing through
four feet of rich, black soil, and, below
this, through upward of ten feet of
gravel, reddish clay, and rounded
quartz. Tere the flint implement was found, and its unmistakable artificial
form so impressed the finder that he secured it, and carefully noted the depth
and the character of the strata under which it lay. Though the actual object
corresponds more to the small and slighter productions of the modern Indian
tool-maker than to the rude and massive drift implement which I had conjured
up in fancy, it has no claims to more artistic skill. Under any circumstances it
would be rash to build up comprehensive theories on a solitary case like this;
but, though small, and otherwise dissimilar to the drift implements of France
and England, there is nothing in the workmanship of the Grinnell Leads flint to
suggest its origin at a later period; for it is only chipped into form with such rude
skill as is fully equalled by that displayed in the former; and may, therefore,
very well accord with the idea of the most rudimentary traces of art being alone
discoverable in the manufactures of the Drift Period.

The growing favor with which this opinion is entertained is illustrated by
the attempts made by Mr. Worsaze and other Danish antiquaries to separate
that Stone Period of prehistoric times, which they have hitherto considered in
connexion with the cromlechs, banta-steins, and other primitive monuments of
Sweden and Denmark, from another and greatly more remote era, or Flint
Period, to which the recently explored kjockkenmaddinger, or shell mounds and
coast refuse-heaps, are assigned. In these, numerous flint wedges and other
implements of the rudest workmanship have been found; but, along with them,
some rare specimens of well wrought and highly finished flint tools or weapons
have occurred. ‘These, indeed, some would still regard as stray relics of a later
date, like the Indian weapons and sepulchral remains superficially deposited in
the ancient mounds of the Mississippi valley. But Professor Steenstrup, who
has been associated with Professors Forchhammer and Worsaz since 1847, in
the exploration of the kjockkenmaddinger, peat bogs, and other formations
which enclose the ancient traces of man, entirely rejects the idea of any interval
of separation between the Kjockkenmeedding Period, and the earliest and rudest
stage of the Danish Stone Age. If, therefore, the two constitute one era, the
purely exceptional character of all but the coarsely-shaped flint implements in
the kjockkenmeedding tends to suggest the probability of further research lead-
ing to the discovery in the drift also of some of the more delicate and carefully
finished flint tools.

In reality, however, the difference is more one of material than workmanship.

298 PHYSICAL ETHNOLOGY.

A certain class of flint axes are found, especially in Denmark, not only ground
to an edge, but with the whole surface polished; but these are comparatively
uncommon on the continent, and are only rarely found in Britain. The
natural fracture of flint brings it nearly to the required shape for knives, arrow
and lance heads, and axe-blades, without grinding. But itis otherwise with the
amorphous trap, granite, and other hard rocks wrought into stone axes, &e.
These had to be rubbed and ground into shape, and some of them are found
polished with elaborate symmetry and finish. If stone implements should
hereafter be recovered under ciggumstances indicative of a corresponding an-
tiquity with the flint manufactures of the drift, the more intractable material
will be found to have compelled the primitive workman to employ some amount
of grinding and polishing on his rudest weapons.

The varied ethnological collections of the Smithsonian Institution, when com-
pletely arranged, will ‘be found to illustrate many interesting points of compara-
tive ethnic art. The examination of the Indian implements already displayed
in its cabinets has now sufficed to recall to mind a flint implement in my own
collection, the significance of which, as a possible relic of older races than the
Red Indians of this continent, was overlooked by me at the time I acquired it.
When passing, some years since, through the village of Lewiston, in the State
of New York, I purchased from an itinerant vender of Indian bead-work some
flint implements, chiefly arrow-heads, such as are constantly ploughed up on
the sites of Indian settlements; but along with those was a large dise, or
spear-head, of dark flint, 43 inches long by 34 broad, which I was informed had
been procured in the neighborhood in the process of sinking a well. Regarding
it merely as an unusually large specimen of an Indian flint spear-head, I de-
posited it among other relies of the same class without further inquiry. But
my visit to W ashington has afforded me an opportunity of examining some
similar dises of flint or hornstone, found under circumstances which give a new
interest to the Lewiston implement. In one of the cabinets of the Smithsonian
collection two large flint implements are deposited, which attracted my eye from
their apparent correspondence to the oval or almond-shaped implements of the
drift, made with a fractured cutting edge all around. A label attached to one
of them is as follows: “ Thirty of these found at the depth of eight tect, under a
peaty formation, near Racine, Wisconsin; deposited by P. TR. Hoy? De.
Hoy is a contributor to various departments of the Smithsonian collections ;
and his name also repeatedly occurs in Lapham’s “ Antiquities of Wiscon-
sin, Surveyed and Described.” At page eight of that work the following state-
ment is made on his authority: “Some workmen, in digging a ditch through
a peat swamp, near Racine, found a deposit of dises of ‘hornstone, about
thirty in number. They were immediately on the clay at the bottom of
the peat, about two feet and a half below the surface. Some of the
dises were quite regular. They vary from half a pound to a pound in
weight.’ Notwithstanding the discrepancy between the two accounts of the
depth at which the implements were found, both statements probably refer to
the same discovery.* The larger of the two specimens measures 54 inches

* In answer to a letter addressed to Dr. Hoy, on this subject, Mr. Albert H. Hoy writes,
January 25, 1863: ‘‘Dr. Hoy desires me to state that the flint discs were found in dig-
ging a ditch throngh the bottom of a ravine near this city, (Racine, Wisconsin,) formerly
the bed of Root river, which enters the lake at this point. The doctor thinks these flints
had been transported from some point and bisried here by the Indians, as a sort of caché,
in order that they might readily find them when they wished to construct arrow-heads,
spear-points, and the like. From the nature of the peaty formation, the doctor thinks
that the flints were deposited after the formation of the surrounding soil. It may be that
the Indians purposely buried the flints in this moist situation that they might remain
damp, as it is known that in this state flint is the easier worked or chipped, Some thirty
more were found at one point, and had the appearance of being deposited in a pile.’’ As
no correction is made of the later depth assigned to their discovery, I presume it to be
correct.

PHYSICAL ETHNOLOGY. 999

long by 33 broad, and the other is only a little smaller. The discovery of sim-
ilar heaps of rudely formed discs of flint has been repeatedly made under
circumstances much more obviously indicating their being placed for some
specific purpose in the deposit from whence they were recovered; and the
immense numbers of them occasionally heaped or systematically arranged on a
single spot is a fact which may have some significance in illustration of the
numerous flint implements recovered from the drift on very limited areas.

The researches of Messrs. Squier and Davis, in the mounds of Ohio, have
revealed the fact that large deposits of such dises repeatedly occur in those
ancient earthworks; and in a manuscript account of researches carried on more
recently in the same locality, which I have had an opportunity of examining
while at Washington, the following narrative occurs: ‘ On the south side of the
confluence of the Racoon and the south fork of the Licking river, at McMullen’s
inn, is a square earthwork, with a small circle attached to the west side. Some
workmen, digging for clay in a brick-yard occupying part of the square, dis-
covered a nest of 198 flint arrrow-heads about two feet below the surface, all
nicely set up on end, the smaller ones within and the larger without. Some
were as large as a man’s open hand, all neatly made, and of the same pattern.”
To this the explorer adds, as a singular fact: “ All the arrow-heads I have
obtained from out the mounds, or in similar deposits, are of this character or
pattern.”

Some uncertainty as to the occurrence of the modern forms of flint arrow-
heads among the genuine deposits of the mound-builders of the Ohio valley is
occasioned by the practice of interment, by the forest tribes, superficially in the
ancient mounds. Certain it is, however, that in those mounds a class of largely
and rudely formed dises, or spear-heads, of flint, quartz, and manganese garnet
is common. Others are chipped into regular form with minute eare, but are
also of unusually large size, and, like the ruder discs, suggest the idea of their
purposed use, without the addition of any shaft or handle. Messrs. Davis and
Squier remark, when describing the contents of the altar mounds explored by
them: “Some of the altar or sacrificial mounds have the deposits within them
almost evtirely made up of finished arrow and spear points, intermixed with
masses of the manufactured material. From one altar were taken several
bushels of finely worked lance-heads of milky quartz, nearly all of which had
been broken up by the action of fire. In another mound, an excavation six feet
long and four broad, disclosed upwards of 600 spear-heads or dises of hornstone,
rudely blocked out, and the deposit extended indefinitely on every side. The
originals are about six inches long and four broad, and weigh not far from two
pounds each.”* The accompanying wood-cut (Fig. 11) illustrates the original
text, and will suffice to show the prevailing forms of the rude implements ; but
it fails to suggest to the mind their great size, and clumsy, ponderous character,
80 nearly approaching, in both respects, to those of the European drift.

Some of the specimens are described as nearly round, but most of them are
rudely heart-shaped. With them were found also several large nodules of simi-
lar material, from which portions had been chipped off. Estimating the whole
amount from the number exposed within the limits to which the explorer’s ex-
cavations extended, they supposed there must have been nearly four thousand
altogether, and possibly a still greater number, under the single mound.

The peculiar circumstances of the deposit at Racine, as deseribed by Dr.
Hoy, where many dises were found lying on the clay with the accumulated
peat formation above them, would, in some localities, suggest an antiquity
measurable by the slow formation of the peat above them; but the extensive
traces of an ancient population, and especially the numerous earthworks in the
State of Wisconsin, suggest the possibility of the collection of stone imple-

= Ancient Monuments of the Mississippi valley, p. 213.

300 PHYSICAL ETHNOLOGY.

ments having been buried where they were found. Of the purposed interment
of those in the Ohio mounds no doubt can be entertained; and though a great
antiquity has been ascribed to the mounds, in comparison with any works of the
known races of the continent, no one will dream of assigning them to a period
bearing any relation to that of the Drift Folk of Abbeville or Hoxne. Here,
then, we find illustrations of one of the commonest types of the drift imple-
ments deposited in vast numbers under the earthworks of this remarkable pre-
historie race of the New World, and found even in its regular sepulchral mounds.

If one of the Racine discs in the Smithsonian collection be compared with the
example from

Fig. 11.—LEWISTON FLINT IMPLEMENTS.

the valley of the Somme, selected by Mr. Evans to illustrate his third class of
oval or almond-shaped implements,* they will be seen to correspond so closely
that either might be selected as the illustration of the type.

* Archxologia, vol. xxxvili, pl. xv, fig 3

PHYSICAL ETHNOLOGY 301

The Lewiston implement is more irregular and ruder in workmanship. It
has been reduced to the required shape by comparatively few strokes, and ap-
pears to have been broken off at the one side by an ill-directed blow of the
stone hammer by which it may be presumed to have been wrought. The oppo-
site and only complete edge is chipped and fractured as if by frequent use. It
is to be regretted that more minute information as to the precise locality and
circumstances of this discovery has not been secured. But it may not yet be
too late for the recovery of the desired data. As an undoubted relic of the
American drift, it would afford startling evidence of a minute conformity be-
tween the most ancient traces of human art in both hemispheres. Even as,
more probably, a stray relic of the ancient monuments of Wisconsin, or the
Ohio valley, it possesses considerable interest to the American archeologist,
thus found so far from the ascertained seats of the extinct Mound-Builders. But
it is probable that the implements of the modern Indians include those of the
very same form. In the same cabinet of the Smithsonian collection, which in-
cludes the Wisconsin examples referred to, is a roughly shaped dise, figured
here, (Fig. 12) brought with other remains from Texas. It measures 44 inches
in length, and, as is shown by the accompanying illustration, it repeats one of
the commonest types of the smaller drift implements, and also corresponds to
them in its irregularly fractured edge and rough workmanship.

Wy

ZA

Fig. 12.—rexas FLINT IMPLEMENTS.

The subject selected for illustration here, from among many which I
brought under the notice of my audience, though apparently trifling, has
a certain significance which may justify its reproduction. A comparison
of the ordinary flint and stone implements, and of the rude pottery still manu-
factured by the Red Indians of the American forests and prairies, with examples
recovered from ancient sepulchres of Britain and the north of Eurcpe, dating
before the Christian era, proves a correspondence in many cases so striking as
to admit of the one being substituted for the other without detection by the
most experienced archeologist. 'l'o prove, therefore, that in the drift under-
aeath the Gaulish and Roman graves of Abbeville and Amiens, or the British
and Saxon barrows of Suffolk, lie imbedded the rude flint implements of an
elder period, essentially differing from both, ftirnishes indications as strikingly

302 PHYSICAL ETHNOLOGY.

suggestive of a different condition of life, and a diverse stage in the progress of
the human race, as the bones of the mastodon or the Ursus speleus which are
imbedded in the same stratified gravel. That the flint-tools have certain char-
acteristics in form and workmanship is unquestionable. Yet the difference
between them and more modern implements of the same maierial has been
exaggerated ; and the results indicated by this comparison of flint implements
‘of the New World with those of the European drift is to show, I think, that
the diversity between the two is not of an essential or very important nature,
and by no means such as would indicate any relative stages in a progressive
development which, in the sober estimation of some of our most cautious geolo-
gists, embraces a period scarcely measurable by centuries. ‘Their present specu-
lations would render the interval between the Flint-worker of the British barrows
of ante-Christian centuries and the modern Indian too insignificant to be taken
into account, in relation to an age when man is assumed to have made his advent
in Britain while it formed a part of the continent of Europe, and when the
glaciers of the Scottish Grampians still contributed their Arctic floods to the
valleys of southern England and France. But also some of the facts indicated
here warn us that we have still to anticipate many new disclosures not less
striking and unlooked for than those of the European drift; and among those
is the possible discovery of America’s drift-period, comprehending the traces of
human art and the evidences of the presence of man in this New World, as it
is called, at periods compared with which that of its Mound-Builders is modern,
and even of its fancied Pheenician colonizers but of yesterday.

AN INTRODUCTORY LECTURE

TO THE

STUDY OF HIGH ANTIQUITY,

DELIVERED AT THE

ACADEMY OF LAUSANNE, SWITZERLAND, ON THE 297TH OF NOVEMBER, 1860,
BY A. MORLOT.

[Translated by the author for the Smithsonian Institution. ]

‘“ What we know is very little, but what we do not know is immense.”—LAPLACE.

[Certain subjects are more developed in this paper than they have been in the lecture itself.
This is especially the case with the delta of the Tiniere. Such details, more interesting for the

geologist, may be omitted by the general reader, who will find it easy to take in merely
the results. ]

The process of reasoning, from the known to the unknown, from what is seen
to what is not seen, is practiced by every one. When the Arab of the desert
deseries at a distance an eagle soaring in a peculiar manner, he exclaims, “A
lion!” He knows that the eagle is waiting to pounce upon the prey which a
lion is about to quit.

In fact, every one is more or less in the habit of forming an opinion by in-
direct means. ‘Thus, a man’s character is judged of by his dress, his language,
and even by his handwriting.

It is, in reality, by the same means that a lawyer arrives at his conclusions,
and the savant—one ought rather to say the student, for the savant is, after all,
but a perpetual student—elaborates his doctrmes. He begins by observation,
which he combines with experiment, when he can modify the circumstances
under which the phenomena observed are produced; he then classifies, co-
ordinates, compares his first results, in order to understand them more fully ;
and, finally, ascending from effects to causes, he arrives at the great principles,
the laws which govern nature. Observation, combined, when feasible, with
experiment, comparison, and finally, induction: this process is the method of
which the result is science.

One of the most striking examples of the application of this process is fur-
nished by geology, which has reconstructed the history of our planet be-
fore the appearance of the human race. But why should we stop at the mo-
ment when for the first time an intelligent being appeared on this earth,
which had bitherto been solely peopled by animals, endowed with instinct
alone? Is not man also part of nature, and does not he, too, belong to the vast
plan of creation ?

The objection might be raised that for the human periods we have the trans-
mission of facts by written records, which is history proper, and by oral tradi-

‘

304 STUDY OF HIGH ANTIQUITY.

tion. But, before the invention of writing, where was history ? and before the
development of language, where was tradition !

The origin of writing is not obscure, showing that the beginning of history
does not date very far back. The origin of spoken language is far more an-
cient, and its study teaches us that it was developed slowly and gradually,
starting from a rudimentary beginning, which necessarily corresponded to an
equally rudimentary state of the human intelligence. This is suflicient to
prove that oral tradition cannot go back to the origin of our species any more
than the memory of an individual can revert to the moment of his birth.

Evidently, humanity has passed through an early phase which has left no
remembrance of itself. How long did these forgotten times last? when did
tradition begin? at what epoch did history, properly so called, take its rise ?
This is difficult to determine.

For southern Europe, history, ascertained chronologically, goes back sev-
eral centuries before the Christian era. For that part of Europe situated to
the north of the Alps, history begins with the Roman invasion, which is nearly
coeval with the Christian era. We have a few historical facts and traditions
of a somewhat older date, but they are not of great importance in the researches
we are about to undertake, and we may pass them over in silence.

It is these pre-historieal and pre-traditional times which we call High An-
Traurry, and which are to form here the object of our study. And we shall
only consider Europe north of the Alps, closing our researches about the time
of the Christian era. Our task is thus precisely limited, and this circumstance
should not be lost sight of in the sequel.

Since the memory of the long period in question is all but lost, we must
seek for other materials wherewith to supply its place. We stand here pre-
cisely in the same position as the geologist who reconstructs the history of our
planet. We shall, therefore, borrow his method, since our mode of proceeding
must necessarily present a strong analogy with his. ‘The materials of the geol-
ogists are chiefly the remains of animal and vegetable creations, the fossils
buried in the strata which form a great part of our continents. Instead of
fossils, we have the remains of human labor and industry. They are tous asa
mirror in which is reflected the image of their authors, of their life, and of their
entire civilization. For the laborer is known by his work. If the geologist
can restore an animal from a single bone, why should we not, with a fragment
of a broken pot reconstruct the entire vase, and from the vase rise to its make ?
The interval is not so very wide from a mere potsherd to man; for every-
thing is closely linked together in the economy of human life as it is in nature.
The primitive inhabitant of our country has long ago disappeared ; his
mortal remains have returned to dust; his tales of war are forgotten, as well
as his lays of love; the very name of his tribe, of his race, is lost; but the
work of his hands yet subsists and enables us to revivify our ancestors ; to see
how they lived and fared ; to observe their domestic economy ; to follow their
commercial traces ; to join them in their hunting parties and in their martial
forays ; to surprise them at some of their religious ceremonies, and to contem-
plate their funeral rites. Thus we transport ourselves into by-gone ages, just
as the geologist has rendered himself the witness of the development of our
planet. This is what we mean by the study of high antiquity or of primitive
archeology.

It is evident that these researches deal only with material objects, but it is
to vivify and compel them to speak, as the fossils of the geologist have been
made to give forth a voice. Nature yields her answers when she is properly
questioned. But we must not ask of the times when written language was
yet unborn to furnish us with proper names; these are completely lost, while
they play an important part in ordinary history. Our studies can only em-
brace the development of civilization, without considering speech. We can, in

STUDY OF HIGH ANTIQUITY. 305

a certain measure, see our ancestors, but we cannot hear them. We must be
content to gaze at them as at so many shadows.

It might be objected that to reconstruct the past by means of the remains of
industry we ought to have an abundance of materials such as are but rarely
found. Yet fossils were formerly considered quite as scarce, though now mu-
seums everywhere abound with them. ‘True it is that time has rarely spared
any of those productions of primitiveeart which rise above the surface of the
soil, excepting here,and there certain monuments formed of large blocks of
stone and certain earthworks. This is especially the case in the countries
which we are about to consider, and where the use of masonry, cemented with
mortar, dates no further back than the time of the Romans. But, let us re-
member that numerous generations have succeeded each other, that they have
strewn the ground with the remains of their industry, and have themselves de-
scended to the dust, carrying with them into their graves many of the objects
upon which they placed the highest value ; we shall then understand that the
vegetable mould must be rich in documents of the past, like the fossiliferous
strata of the geologist, and that these documents only require to be skilfully
sought for and properly interpreted. The ground that we tread is the grave of
the past, a vast grave, always open, and which is to receive us ae with the
remains of our industry and for the benefit of future antiquarians.*

It is also true that the preservation of antiquities is very partial, the fleshy
and vegetable substances having generally disappeared, so that it is rare when
anything but glass, metal, or pottery has resisted the action of time. But it
is the same with the remains of the ancient organic creations ; for it is chiefly
only the solid parts of plants and animals which the strata of our globe con-
tain as fossils. And yet the geologist has turned them to good account. The
task of the antiquary is not more difficult.

Tn certain cases the preservation of antique remains is more perfect. Thus,
when imbedded in peat, or in the mud at the bottom of lakes, vegetable matter,
such as seeds, wood, and even remnants of woven stuffs, have been found pre-
served. When the substance was charred by the action of fire, before falling
into the lake, it became unalterable. Thanks to this cireumstance, we have
discovered in Switzerland bread and even ears of corn several thousand years
old.+ Far from being scarce, the records of by-gone ages will become more
abundant as they are more carefully sought for, and the materials for recon-
structing the past of the human race will not be more difficult to obtain than
those by means of which the geologist writes the history of our earth.

It might seem, from what has been said, that in forming collections of an-
tiquities, and in studying them rationally, the outlines of the science would
have been soon traced, and its fundamental principles, which are always sim-
ple, readily arrived at. It is long since the collection of antiquities was com-
menced, but they were considered, as were at. first fossils and other objects of
natural history, as mere curiosities, even when they were not turned into talis-
mans and amulets. Again, when their meaning was sought, sterile and inter-
minable controversies were carried on, as is always the case at the dawn of 2
new science, so apt is human reason to lose its way.

A prejudice which has been and is still a great hindrance to progress is the
belief that everything skilfully wrought must be of Roman origin, especially
objects in metal, the more Cau remains being neglected and overlooked.

alt ata be Paces a great service to atu science if the date were iseabed

wherever it is possible to mark it, particularly on glass and metal, but more especially upon
erocker

ii Seo 38 the Memoirs of the Society of Antiquaries, at Ziirich, for 1854, 1858, 1860, 1861,.
and 1863, the remarkuble reports by Dr. F’. Keller, of Zurich, on the ancient pilew orks of
Switzerland. Every memoir published by the society can be had singly on applying to the:
bookseller.

20s

306 STUDY OF HIGH ANTIQUITY.

Hence the false conclusion that before the Roman invasion the north of Eu-
rope was only inhabited by hordes of barbarians. Geology passed through a
similar stage when all fossils were considered as vestiges of the deluge. ‘Tho’
customary misconceptions prevailed also in the south of Sweden and in Den-
mark, countries which abound in antiquities, such as flint axes. These were
thought by some to be implements used for sacrificial purposes during the
time of heathenism ; others even believed them to be thunderbolts, an origin
which has also been attributed to the fossils called belemnites.

‘The prevalence of such fancies may give an idea of the state of the question
when Mr. Thomsen, director of the archxological museum, at Copenhagen,
and Mr. Nilsson, professor of zoology at the University of Lund, in Sweden,
began their labors. These illustrious northern antiquaries, too practical to
enter into the controversies then in vogue, began to compare the antiquities
of their own country with the industrial productions of the more or less savage
tribes of Australasia and other regions of the globe. ‘This comparison at once
brought to light a remarkable analogy between the flint instruments of the
north of Europe and the implements of existing races not yet acquainted with
the use of metals. MM. Thomsen and Nilsson observed at the same time that
a whole series of characteristic tombs contained, besides the skeletons and some
rude pottery, implements of stone only, without any trace of metal. All this
suggested, very naturally, that the first inhabitants of the north of Europe had
not been acquainted with the use of metals, and bore no little resemblance to
the savages of the present day, at least in what concerns the habits of every-day
life. Another class of tombs contained cutting implements and arms of metal,
axes, knives, swords, spear-heads ; not, however, of iron or steel, but of bronze,
a mixture of copper and tin. Jad iron been known, it would certainly have
been used in preference. It follows that. bronze was known and employed be-
fore iron. Nor can there be a doubt that what iron is now, and has long been,
for purposes of industry and the requirements of civilization in general, bronze
once was, and stone, chiefly flint, previous to bronze.

Thus was established the plain and practical distinction of the successive
ages: First, that of Stone, next that of Bronze, and lastly that of Iron. This
classification, which recalls Werner’s division of the geological formations into
primitive, secondary, and tertiary, was introduced about thirty years ago.*
At first applied only in Scandinavia, it spread by degrees to Germany, England,
and Switzerland, and is beginning to penetrate, by Piedmont, into Italy,t
rendering everywhere essential service.

Attempts are now made to subdivide these three great phases in the devel-
opment of civilization, Some antiquaries, such as Mr. Worsaae, think they
ean, from the quality of the objects and the mode of the sepulchral constructions,
distinguish a first and a second sub-period in the stone age. The learned
explorer of Mecklenburg, Dr. Lisch, at Schwerin, thinks that during the first
centuries of the bronze age the casting in metal of pieces hollow inside was
unknown, and that such pieces indicate a considerable progress, characterizing
the latter times of the bronze age.t In Denmark and in Switzerland an

* The northern savants did not publish their results till several years after having
obtained them. Mr. Thomsen printed a paper in Nordisk Tidsskrift for Old Kyndighed.
1832, and a very good general treatise, Ledetraad il Nordisk Old Kyndighed, Kjoebenhavn,
1836, of which there appeared a German edition at Hamburg in 1837, and an English edition,
‘““A Guide to Northern Antiquities, London, 1837.” Professor Nilsson published a work
on the primitive inhabitants of Scandinavia: Scandinaviska nordens urinvonare, Lund, 1838,
1843. ‘This latter work is a real masterpiece, worthy of ranking with G. Cuvier’s immortal
publications, and a second edition in Swedish and in German is about to appear. :

t See B. Gastaldi’s valuable paper, Nuovi cennisuglt oggetti di alia antichita, trovati
nelle torbicre e nelle marniere dell’ Italia: Torino, 1862. ‘These researches have been taken
up and are continued with great talent by Professor B. Strobel, assisted by L. Pigorini,
both at Parma.

¢ The author, who has carefully studied the museum at Schwerin, the capital of Meck-
lenburg, does not think this subdivision sufficiently well established.

STUDY OF HIGH ANTIQUITY. 307

early pre-historical iron age is also beginning to be recognized and to be distin-
guished from a later iron age, belonging to the historical era. Itwas necessary to
begin by establishing a snail number of distinctly characterized periods, as
had been done also in geology. But it is becoming evident, in antiquity as in
geology, that there have been gradual transitions from one period to the next.
Thus, though the presence of cutting implements of bronze generally excludes
the Se rltaneous presence of iron, fiers are tombs, like those at Hallstatt, in
the Austrian alps, which contain the bronze sword, together with the knife or
the axe of iron. But in this case an attentive study Twa teach us that the
burials belong to a time of transition from bronze to iron. At Hallstatt the
transition has evidently taken place slowly and gradually. In other instances
it seems almost to have been brought about violently, perhaps by foreign
invasion, or by internal revolution, presenting a certain analogy with the
geological convulsions which have so often established a break between imme-
diately overlying strata.

We have seen how the foundations of our science have been laid. Some
of its chief principles have been disclosed by the historical sketch, but we
must consider them more closely and dwell with greater detail on our method
of research.

If we seek to understand the past of our species, we must evidently begin
by ascertaining its present state; we must study man, not only in civilized
countries, but mahene »ver he has sevileds Hence we see that E’rHNOLOGY is to
be taken for our starting point, and that it contributed largely in guiding the .
northern antiquaries is the right path has already been already shown.
Ethnology is for us what physical geography is for the geologist. We can
only understand the former state of our globe by studying its present condition
and by following the changes which take place on its surface, as Lyell, the
reformer of geology, has so well taught.

Every nation has always had some special mode of manufacturing and of
ornamenting its productions, and, moreover, its peculiar habits and customs,
impressing a distinctive stamp upon its art and industry. This constitutes
what is called stryLe. In Europe, north of the Alps, the style was generally
pretty uniform during a given era, but it varied continually from one age to
another, just as the £,euile species have changed their types from one eeolowice al
period to the next. The appearance of an object will oe often suffice to
determine its age and the relative date of its interment, as we can determine
the relative age of a geological stratum by a single fossil, peel this is charae-
teristic. In che forte of Europe bronze bracelets were worn during the entire
bronze age and during the early iron age; but their style is very different, the
fashion having changed. Thanks to this circumstance, one is rarely embar-
rassed in determining the age of a bronze bracelet, or of a mere fragment of
such a bracelet.

It is not enough that when making field researches we accumulate antiqui-
ties merely for “the purpose of forming a collection of them. It is of the
greatest interest to observe the AssocIATION of the objects, in order to decide
which are of the same date, just as it is important to assort together the fossils
found in the same stratum. Taken separately, the fossils, like isolated words,
would not in themselves be of so much importance, whilst their concourse,
like a logical phrase, may throw a vivid light on a whole era of the geological
past. Tn this respect, tombs are of great value, for the series of objects which
may be contained in one and the same grave harmonize, and are necessarily of
the same date. Nor must we forget that the very mode of burial has varied
from one age to another—a eineumct: unce which gives still greater value ta the
eaamunetice of this species of monument. We Tere already seen how much

the study of the tombs contributed to guide the northern antiquaries into the
right path.

308 STUDY OF HIGH ANTIQUITY.

The question of the special PosITION (gisement in French, laderung in Ger-
man) in which objects are found, so important in geology, is not less so when
we consider the traces of the human past. The peculiar position of antiquities in
the various places where they are met with has often a special signification.
Thus, to return to the graves, their interior, carefully examined, will often
reveal the funeral customs and may furnish us with notions respecting the
religious ideas of the time. Sometimes, and it is found to be generally the
most ancient mode, the body was bent up, with the knees joining the chin, as
if to occupy the least possible space. Later the dead were usually burnt,
which might lead us to suspect the worship of fire. Then again the body has
been found stretched out horizontally. When several contemporary skeletons
are discovered in the same mound, their relative positions may lead us to infer
the practice of human sacrifices. In this case the victims will generally be
found lying scattered about irregularly, as if they had been thrown in carelessly,
while the centre of the grave has been reserved for the individual in whose
honor the funeral rites and sacrifices were instituted. By observing the posi-
tion of some broken pebbles and of fragments of pottery in the earth covering
certain ancient tombs, Dr. Keller, of Ziirich, inferred the custom of casting in
these objects while raising the mound—a practice which a curious passage
from Shakspeare, (Hamlet, act V, scene I,) seems to confirm.* It would
appear that the funeral was occasionally combined with a feast on the spot,
and that the earthenware which had been used was broken up and scattered
over the grave. At other times the entire vases, or such as have been onl
crushed by the pressure of the earth, seem to have contained food for the
departed, with whom were also frequently interred his trinkets, his arms, the
emblems of his trade, sometimes his dog, his horse, and even his wife.

The question of SUPERPOSITION is connected with the preceding. It plays
here as essential a part as in geology, which it furnishes with the chronological
succession of the different strata, since, evidently, an overlying bed must be
more recent than the one beneath it. The antiquary meets rarely with series
of strata as regularly superimposed as those of the geologist. The case would
be more frequent could we examine the deposits which are formed at the
bottom of lakes and seas. But, then, the geologist would have taken the
advance, and would himself have retraced the history of the human race, leav-
ing but scanty gleanings for the succeeding explorers. The materials of the
antiquarian are usually buried in a thin layer of vegetable mould, though even
that is sometimes wanting. 'There are, however, on terra firma, cases of super-
position of deposits containing human relics. They are of great value, for
they establish more surely than could be done in any other manner the chro-
nological succession of the different ages. In fact, every distinction between
ages should invariably rest upon some direct observation of superposition.
We have seen how the northern antiquaries arrived at their three ages of
stone, bronze, and iron. ‘Their results are satisfactory, but still, having been
obtained somewhat indirectly, they are even yet occasionally disputed. Such
facts, however, as the following are of a nature to settle the question defini-
tively :

Graves of the early iron age, established upon sepulchral mounds of the
bronze age, and, in other cases, interments of the bronze age upon the site of
those belonging to the stone age, have been accidentally noticed in Denmark
and in the adjoining duchy of Mecklenburg. But the most complete example
ef such superpositions has been observed, and carefully, too, at Waldhausen,
near Lubeck. One of those ancient tombs existed there, in the shape of a
mound or barrow, 13 feet high and 161 feet in cireumference. It was levelled
to the ground to insure a thorough examination, as serious research requires.

* Memoirs of the Society of Antiquaries at Zurich. Vol. III, part V, 1845.

STUDY OF HIGH ANTIQUITY. 309

Just beneath the surface was discovered an ancient grave, to all appearance of
pre-historical date. It was occupied by a skeleton, with fragments of coarse
pottery and with a piece of iron, rusted away. Lower down, at about midway
the depth of the mound, were three tombs of the bronze age. They consisted
of small chests or cells of stone-work without mortar, and containing each a
cinerary urn filled with fragments of calcined bones, mingled with various ob-
jects of bronze, such as neck-collars, hair-pins, and a knife. Finally, at the
bottom of the mound was discovered a sepulchral chamber of the stone age,
formed of large unhewn boulders, and containing coarse pottery and _ flint
hatchets. Evidently the first inhabitants of the country had constructed, upon
the natural soil, a tomb, according to the custom of the times, covering it over
with earth. Upon this elevation some interments of the bronze age had taken
place, and another covering of earth was added, thus doubling the height of
the mound. Finally, in the early iron age, a corpse had been buried by dig-
ging a tomb on the summit of the hillock.*

Thus, what at first sight appears to be only one tomb, may furnish antiqui-
ties belonging to different periods, and it is of the utmost importance to carry
on the researches so as carefully to determine the exact relative position of
whatever presents itself, if serious mistakes are to be avoided. MM. Castan
and Delacroix, at Besancon, surprised to find a mixture of objects which they
thought belonged to different periods, succeeded in distinguishing, in the same
mound of only slight elevation, burials of the Roman time, established over
Gallic entombments of the early iron age, proving thus an indigenous civiliza-
tion, based on the use of iron, and previous to the Roman invasion.t

But the incident of mere superposition, notwithstanding its value, can only
furnish notions of relative chronology, expressed like those of geology, which
knows of no absolute dates in numbers of years or of centuries. And yet we
could wish to know when each of the three ages of stone, of bronze, and of
iron began, and how long each lasted. ‘The best that we can do is to acknowl-
edge our ignorance. ‘The introduction of iron is itself a pre-historical event ;
even tradition is silent about it; how much, then, must the preceding ages of
the bronze and of the stone lie further back, beyond all memory! ‘The prob-
lem can only be solved by the aid of geology, by finding out cases of some
regular and constant action of the elements, connected with marks of the prin-
cipal human periods. ‘The following is an example, which will show how dates
of ABSOLUTE CHRONOLOGY are to be obtained :

The alpine torrents, when they issue from the ravines or small lateral val-
leys, which give rise to them, accumulate their alluvium in fan-shaped deposits,
or portions of cones of a very regular form. ‘These are real deltas, but with a
surface necessarily more inclined than is the case in those of rivers. he
inclination of the cone depends on that of the torrent in its previous course,
on the volume of the water, and on the quantity of shingle it drifts. This
inclination varies with each torrent, and the limits of the variation are, on the
one hand, the descent of rapid rivers; on the other, the slope of any accumula-
tion of loose matter formed without the intervention of water, as, for exam-
ple, in certai landslips. The usual inclination of these torrential deltas inthe
Alps ranges between 2 and 5 degrees. An inclination of 7 degrees is much
less frequent, and the cases where it reaches 15 degrees are rare. If the
form and nature of the hydrographical basin of a given torrent and the
meteorological circumstances, such as the annual quantity of rain, do not
change, it is evident that the torrent cannot alter the form nor the inclination
of its cone or delta. The latter will consequently grow by concentric layers,

* Beitraege zur nordischen Alterthums Kunde, vom Verein fiir Lubeckische Geschichte.
J. Heft, Lubeck, 1844.
t Mémoires de la Société d’émulation du Doubs. Besangon, 186].

310 STUDY OF HIGH ANTIQUITY.

preserving regularly the same inclination. In ordinary times the torrent flows
along the central region of its cone; there also it drops its largest boulders in
times of inundation, distributing the gravel and less coarse shingle over the
sides of the cone, for the relative volume of the drifted stones must diminish
with the force of propulsion of the water from the central region of the cone
towards its two edges. It is clear that a torrent, left to itself, cannot raise the
surface of its cone unevenly and create hollows and prominences. Tor if the
surface were raised on any one spot, the water would immediately flow round
and fill up the less elevated parts with drift. ‘The action of water is essentially
levelling. The great number of torrential cones, or deltas, which the author
has had the opportunity, during the last 15 years, of examining in Switzerland
and in the Austrian Alps, have always showed a regular surface. There may
be slight irregularities in the action of a torrent from one year to another, but
pr oceeding chiefly from meteorological variations, they become insensible, when
the cone is considered in its totality; even at a given spot they will rapidly
become levelled and efiaced by the continued action of the torrent itself. We
must also consider that the alluvium of a torrent is furnished by a slow degra-
dation of its hydrographical basin, which can only yield the drift matter grad-
ually, a circumstance necessarily contributing to regulate the growth of the
cone. Thus, when in July, 1848, the torrents in Corinthia (eastern Alps)
were swollen and brought downa disastrous quantity of drift, the author heard
the country people ascribe the damage, in good part, to the circumstance that
the upper region of the water-courses had been more than usually encumbered
by loose matter.

The torrent of the Trniere, where it flows into the lake of Geneva, at
Villeneuve, (Switzerland,) forms a cone or delta, such as we have just described.
This cone has an inclination of 4 degrees, and its opening, or the angle at the
top of the delta, measures about 700 degrees; its radius, taken as a minimum,
being 900 Swiss feet, (one Swiss foot equal to 0.3 metres, is divided into 10
inches i)

Modern embankments, in the shape of solid walls, having forced the torrent
somewhat towards its right bank, on the northern side of the cone, the alluvium
has since been accumulating more on that side, and has raised the surface here,
whilst the southernmost part of the cone ceased to increase. Documents pre-
served in the parish archives of Villeneuve mention these embankments as
having been built in the year 1716, and their recent origin is confirmed by the
scanty covering of vegetable mould on that part of the cone which was protected
by them. Here, where the ground had not been cultivated, there was only
from 2 to 3 inches (6 to 9 centimetres) of earth, inclusive of the space occupied
by the roots of the grass. The railroad has cut transversely through this cone
perpendicularly to ba axis, the cutting measuring 1,000 feet in length, and
reaching in its central part, where the cone is highest, to 324 feet above the
definitive level of the rails. The section thus obtained (sec page 316) may be rep-
resented by the segment of a circle, rising to 324 feet above its chord of 1,000 feet.
Happily for science, the works for the railw ay have been carried on very
slowly at this spot; they were begun in 1856, and are not entirely finished
now, (Barehs 1863.) The author followed them attentively from the beginning.

‘The cone’s interior structure, brought to light by this beautiful cea sec-
tion, was found to be most regular. Te the ce nana region the rounded boulders
attained a diameter of 3 feet, as in the actual bed of fiite torrent. From thence
the drifted matter gradually diminished in size along the two halves of the cone
towards the two extremities of the cutting. There was an exception for the
alluvium formed since the embankments of. 1710, for here the drift was naturally
coarser than in the underlying part. ‘The waters of a torrent are not apt to
produce a marked prenieaiont: of which but slight traces were to be seen, and

STUDY OF HIGH ANTIQUITY. oid

these beyond the central region in the two sides. But where stratification be-
came apparent, it was perfectly parallel with the present surface of the cone.

All these cireumstances go to establish in a highly satisfactory manner the
regularity in the formation shel growth of the cone. Now, as the hydrographi-
cal basin of the 'Tiniere, surveyed throughout by the author, is regular, and
shows no traces of landslips or of other accidents s, which might have disturbed
the regular working of the torrent, and as the metcorology of the country does
not appear to have undergone any alterations of note in modern times, we may
admit that the rate of formation and of growth of the cone in question has
been proportionate to the volume of its alluvium. The partial clearing of the
forests in the hydrographical basin of the 'Tiniere may have contributed in some
slight degree to accelerate the supe rficial degradation of the latter. But if this
efféct had been marked, which is doubtful. ‘it would tend to carry higher the
dates we shall proceed to deduce, and not to bring them lower down.

In the southern flank of the cone, where it was protected, as we have scen
by the embankments of 1710, three beds or layers of ancient mould were dis-
covered, situated at different depths, which had, each in its time, formed the
surface of the cone. ‘These three layers were regularly interstratified in the
gravel exactly parallel with each other and with the modern surface of the
cone, which was itself most regular and inclined by 4 degrees along the line
of the steepest dip.

The first of these beds of vegetable mould was found from actual observation
to extend, in the southern part of the cone, over a surtace of more than 15,000
square feet. It was from 4 to 6 inches thick and was situated at a depth of 4
feet beneath the present surface of the ground; (more exactly at 0.14 metre,
measured down to the bottom of the bed.) It belonged to the Roman era, as
it was found to contain angular fragments of Roman tiles and a Roman coin in
bad condition, but of too good a type to be of the lower empire. The Romans
invaded the country after she battle of Bibracte, 58 years before Christ. Allow-
ing them a century to settle in Helvetia and to raise buildings covered with tiles,
this Roman bed would date, at the most, 18 centuries back. In the year 563
after Christ, the tremendous landslip of Tauredunum ravaged the neighbor-
hood; by that time the Roman dominion had passed away ot had made room,
about a century before, for the reign of the Burgundians, who do not appear to
have practiced masonry or the seniors of tiles. The Roman bed must
consequently be at least 13 centuries old.

The second bed of ancient mould was followed up, on the southern side of
the cone, over a space of about 25,000 square feet. It was about 6 inches
thick, and stood 10 feet (more exactly at 2.97 metres, measured down to the
bottom of the bed) below the present surface of the ground. It contained a
few fragments of potte ry, made of clay mixed up with ervains of sand, and un-
varnishe d; also a pair of tweezers, (for plucking out the hair.) cast in bronze,
and of ihe characteristic style of the bronze-age.

The third and lowest of these beds of mould was uncovered, on the southern
ride of the cone, over a space of about 3,500 square feet. It was from 6 to 7
inches thick, and was met with at a depth of 19 feet (or, to be exact, 5.69 metres)
below. the present surface of the cone. It yielded at one point on the north
side of ihe cone a human skeleton, the skull of which was very round and
small, and remarkably thick, showing a strongly-marked Mongolian (turanian
or brachycephalic) a according to the measurements and examination insti-
tuted on the spot by T. M. G. Montagu. The same bed yielded at another
point, on the southern stile of the cone, numerous fragments of very coarse
pottery, charcoal, and broken bones of animals, evide mtly kitchen refuse. The
bones have been examined by Professor Rutimeyer, at Bale, author of a re-
markable work on the animal remains of the antique pile works or lake dwell.

312 STUDY OF HIGH ANTIQUITY.

ings in Switzerland.* Allowing that the bones in question are too few and
insufficient to admit of very satisfactory conclusions, the learned professor
makes out the ox, goat, sheep, pig, and dog, all domestic, and with characters
which seem to point to the end of the stone age, or to the beginning of the
bronze age. Weighing all the different circumstances, and avoiding undue
precision, we may consider this third bed as belonging to the stone age, although
the author, who explored it diligently, has not had the good fortune to discover
in it any stone hatchet or other antiquity of that sort. At one spot, on the
southern side of the cone, some charcoal was found in a bed of gravel one foot
lower than the above mentioned layer of the stone age; consequently, at 20
feet (or, to be exact, at 6.09 metres) below the actual surface of the cone. It is
worthy of note, as the art of baking bricks and tiles is generally allowed to
have been introduced into the country by the Romans, that below the line of
the Roman period the author never discovered the slightest trace of bricks or
tiles.

‘Towards the central region of the cone, where the cutting was deepest, the
three beds in question disappeared; naturally enough, as it was here that the
torrent’s action was most violent, easily washing away any mould which might
have formed on the surface. As the torrent, in deviating to the right and left of
its central current, lost some of its power and drifted less coarse matter, it would
be more apt to overlay with new deposits, without abrading a layer of mould
or earth formed since the preceding inundations. Quite in accordance with
this there was found in the gravel on the southern side of the cone, at a spot
where the mould bed of the bronze age had quite disappeared, but still 10 feet
below the present surface, a hatchet-knife of bronze, considerably oxydized,
and a well-preserved bronze hatchet which had evidently not been worn by the
movement of the water. ‘The specific weight of these two objects must have
kept. them in place, while the earth which surrounded them was probably swept
away by the torrent. ‘Though the three beds of ancient mould disappeared
thus in the centre of the cone, they reappeared symmetrically on the other or
northern side. But here they stood at a greater depth beneath the present
surface, because the torrent, as we have seen, accumulated its alluvium on this
side. Yet here, also, the beds were parallel to each other. and the vertical dis-
tances which separated them were the same as on the other side of the axis, in
the southern part of the cone. ‘There was, in the northern part of the cutting,
a depth of 6 feet from the Roman bed to the base of the bronze bed, and 10 feet
from this last to the bed of the stone age. It was impossible to mistake these
three beds, or to confound them one with another. ‘The stone-age bed was too
little interrupted in the central region to allow the observer to deviate from its
proper line of prolongation. 'The bronze-age bed was interrupted to a greater
extent, but on both sides of the cone it was equally characterized by being
formed of clayey earth of a bluish color, somewhat similar to the blue glacial
mud, and bordered towards its upper and lower limit by more sandy zones,
colored yellow by hydroxyde of iron. ‘This was remarkable, and evidently
indicated some peculiar cause. ‘The stone-age bed sometimes bore a similar
aspect, but only occasionally and not so regularly as the bronze bed. The
Roman formation on the northern side was only recognized by its height above
the bronze-age bed; no fragments of Roman tiles were found here, but it was
only laid open over a short space, about 40 feet along the railway line, whilst
the bronze-age bed was regularly and distinctly followed on the northern side,
over a distance of 200 feet.t

* Rutimeyer, Die Fauna der Pfahlbauten der Schweiz. Basel, 1861.

t The intersection of the bronze-age stratum with the masonry of the bridge, which
conveys the torrent over the railway, has been marked on the eastern side, opposite the lake,
by a thick line of reddish paint. It is easily discovered in passing in the railway train, being
at the height of the windows of the passenger carriages.

STUDY OF HIGH ANTIQUITY. ole

Now, considering the measurements and researches conducted on and in the
southern side of the cone or delta, making due allowance for the effect of the
embankments, but, to remain on the safe side of the question, doubling their
age—that is, supposing them to be three centuries old; taking into account
the thickness of the vegetable mould on the present surface; observing that
the volume of the cone increases in the ratio of the cube of its radius ; aserib-
ing to the Roman formation an age of at least 13, and at most 18 centuries ;
and remembering that the cone must have taken time for growing, in propor-
tion to the volume of its alluvium, we find, by calculation, for the bronze-age bed
of mould a date of from 29 to 42 centuries ; for the stone-age bed a date of from
47 to 70 centuries ; and for the entire cone an age of from 70 to 110 centuries.
The author thinks that it would be sufficiently exact, though still within the
limit, to deduct but two centuries for the action of the embankments, and to
allow for the Roman bed an age of 16 centuries. This would give for the
bronze-age bed a date of 38 centuries (2,000 years before Christ,) for the
stone-age bed a date of 64 centuries, and for the entire cone, corresponding
with the modern geological era, an age of about 100 centuries, which latter
number must appear a minimum to the geologist. But, not to reckon too
strictly in counting by centuries, let us say that the bronze-age bed is from
three to four thousand and the stone-age bed from five to seven thousand years
old.

It is clear that each of these ancient beds of mould cannot represent the total
duration of each corresponding age, but merely a fraction of each of these
ages, a period more or less protracted, during which the torrent has worked
along the central region of its cone without overflowing its sides, on which
vegetation could then take root. The surface of the cone must usually have
been formed of bare shingle, upon which only a few shrubs could thrive.
This explains why no traces of human habitation were noted in the gravel
interstratified between the three beds of ancient mould. ‘The clayey nature
of the latter seems to indicate that they probably owed their origin to inunda-
tions of an exceptional character, forming loamy rather than gravelly deposits,
thus favoring the development of vegetation and attracting man to the spot.
It might possibly be objected that, these three beds having been deposited by
the torrent, the ancient remains which they contain might also have been
swept down by the water from some other locality, in which case the age of
these formations would remain undetermined. But the ancient remains were well
preserved and evidently not worn by translation; the fragments of pottery
and of bricks were angular, as were also the small pieces of charcoal scattered
through each of the beds, all three of which contained, moreover, entire shells of
various species of snails. The objection raised falls, therefore, to the ground.

Let us here notice that the minimum date of 29 centuries for the bronze-age
bed agrees very well with the purely archeological deductions, which carry
back the introduction of iron into our countries to at least one thousand years
before the Christian era.* This correspondence is the more complete, as
the style of the tweezers found in the bronze-age bed indicates the end rather
than the beginning of that age. If that minimum of 29 centuries for the date
of the bronze bed be correct, the minima dates of 47 centuries for the stone-
age bed, and of 74 centuries for the age of the entire cone, must also be correct,

* See the chapter on the chronological question in the Etudes géologico-archéologiques
en Danemark et en Suisse par A. Morlot. Bulletin de la Société vaudoise des sciences natu-
relles, Tome VI, No. 46—Lausanne, 1860; reproduced in English in the ‘‘ Smithsonian Re-
port for 1860: Washington, 1861.’’ Greek coins of the oldest type are met with on the sbores
of the Baltic, as faras the island of Oesel. ‘Throughout Germany, as far as the Danish archi-
pelago, are found certain antique objects, indicating commercial intercourse between the
north and the south of Europe long before the Christian era. This implies for that period
the knowledge of iron in the north of Europe.

314 STUDY OF HIGH ANTIQUITY.

while the maxima obtained may in reality be underrated. Thus the maximum
ef 110 centuries for the age of the entire cone is evidently rather below than
above the mark. Still it appears from the latter number that the modern
geological period to which the cone or delta of the Timiere corresponds has
not been very long, and that, soon after its beginning, man inhabited Europe.
This is confirmed ‘by the study of the peat- bogs in Denmark and in Switzer-
land. ‘The rude flint hatchets found in England and in France in drift gravel,
associated with the bones of the elephant (elephas primigenius) and of other
extinct species, would seem to carry back the appearance of man in Europe
to an epoch even preceding what is usually considered as the modern geolo-
gical period.*

Let us further notice, that if the stone-age bed really belongs to the begin-
ning of the bronze age, it follows that the Tatter has lasted from two to three
thousand years, since the tweezers found in the bronze-age bed, at a depth of
ten feet, point, as we have seen, belonged to the end of the age. Hitherto we
had been !eft without the faintest notion as to the real length of the bronze age;
it was only evident, from the quantity and the quality of its remains, that it
must have been of long duration.

We have thus attempted to substantiate for high antiquity the first data in -

system of absolute chronology, expressed by thousands of years. The
opportunity has been singularly favorable, it is true, but it has the defect of
being the first and only case of its kind. Let us hope that others will not be
long 1 in presenting themselves, and that they will be turned to good account ;
for as long as a fact remains isolated, the inferences drawn from it cannot be
verified by comparison, and the mind cannot rest fully satisfied.t

But what avail these researches into the past, when the present more than
suffices to engross our attention? The question is legitimate, and it is right that
we should close with some reference to the END AND PRACTICAL USE of our
study

When the philosophers of ancient Greece exercised their ingenuity in investi-
gating the properties of the conic sections, they little thought they were laying
the foundation of the modern methods by which are calculated the astronomi-
cal tables that guide the mariner’s course. No one asks at present what is the
use of mathematics.

Less than a century ago geologists would have been rather puzzled to de-
monstrate the practical utility of their labors. Now, it is easy to furnish the
most satisfactory exemplifications of geology to industry.

Every step in the acquisition of real knowledge, the least secret of nature
duly unravelled, has its intrinsic value, and will sooner or later contribute
towards the well-being of our race. But science requires time for clearing its
ground, for sowing its seeds, and for bringing in its harvests. Archeology is
even younger es its sister geology, and we must not be surprised if it has
not as yet matured its fruits. The following, however, may be accepted as a
word of apology in its behalf:

Nature forms one harmonious whole, of which the compound elements have

*'T. Prestwich, on the occurrence of flint implements, &c.: Philosophical Transactions,
Part IZ, 1860.

{ This first attempt has already met with a singular corroboration through researches
ot Mr. Gillieron at Neuveville, on the lake of Bienne, Switzerland. ‘This shrewd and careful
observer makes out for a pile-work or lake dwelling of the stone age at Pont-de-Thieile, in
his neighborhood, an antiquity of 674 centuries. See Actes de la socitté jurasienne a’ ému-
lation. Année, 1860. A calculation of the age of some pile-works in the peat at Les Uttins,
near Yverdon, Switzerland, has been proved to be a failure. See the paper by Mr. Tayet in
the Bulletin de la société vaudoise des sciences naturelles. 16 Avril, 1862. These chro-
nological researches in Switzerland are dwelt upon by Sir Charles Ly ell in his new work,
“The geological evidences of the antiquity of man. London, 1863."

STUDY OF HIGH ANTIQUITY. 315

the most intimate reciprocal relations. Consequently, a knowledge of the
present throws light upon the past, and reciprocally the past renders the present
more clear. We know the observations upon the changes which are now
taking place on the surface of the globe are necessary to enable us to compre-
hend the geological results of past times to explain the present condition of
the continents. The naturalist who would have a satisfactory idea of an or-
ganized being, even after dissecting it, must study its development from the
first germ, and this germ itself cannot be fully comprehended without a knowl-
edge of the entire being. And as regards.man, could he account for his present
condition without reviving the recollections of his youth, or could he under-
stand his infancy had he not ripened into manhood ?

Thus, if the knowledge of the present state of our race is necessary for
reconstructing its past ages, the study of antiquity is also indispensable for the
proper comprehension of the present, and for arriving at a real understanding
of the social relations which constitute the life of nations. It will therefore
be an immense gain when the progress of scientific research into the develop-
ment of our race shall substitute positive notions, rich in practical application,
for those vain and empty political discussions which, orginating in ignorance,
end in érror.

Finally, if the astronomer has succeeded in foretelling the movements of the
celestial bodies, because he has detected the laws which govern them, may we
not hope, with Condorcet,* that when the present shall be well understood
as a necessary result of the past, we may be enabled in some degree to pene-
trate the mysterious future? 'This would be one of the most glorious, and cer-
tainly also one of the most fertile, triumphs of human intelligence.

Let us, then, study the past, in order that we may understand the present,
and perhaps catch a glimpse of the future.

* Condorcet. FEsquisse d’un Tableau Historique du Progrés de L'esprit Humain:
Paris, 1798: page 332.

316 STUDY OF HIGH ANTIQUITY.

SECTION OF THE CONE OR DELTA OF THE TINIERE.

R. Roman stratum, at a depth of 4 feet, on the southern side.

B. Bronze-age stratum, 10 feet deep, from 3 to 4 thousand years old. +, spot
where a hatchet-knife and a hatchet, both of bronze, were found.

S. Stone-age stratum, 19 feet deep, from 5 to 7 thousand years old. In it
have been found: at a, a bit of pottery; at 4, a human skeleton with a very
small, round, and thick skull of the Mongolian or turanian type, (brachycep-
halic ;) at d, numerous fragments of very rude pottery, much charcoal, and a
number of broken bones of quadrupeds.

A. Central axis of the cone, which cone is cut transversely by the railway.
It was here that the torrent flowed in ordinary times, before it had been driven
more northwardly by dams.

CC. Surface of the cone, when the dams were raised. This line is, to a
certain degree, ideal; all the others are such as have been ascertained by direct
observation.

MN. The railway line.

V. Bridge, serving also as an aqueduct, to carry the torrent over and across
the railway.

OPN. Region to which refer exclusively the measurements that have
figured in the chronological computation. ‘These measurements, often repeated,
were susceptible of being taken here with considerable accuracy; they may be
considered as within half an inch of the truth.

The section has been interrupted in M, because there it becomes indistinct.
Its southern end was perfect in every respect.

Some persons will perhaps infer from the regularity of the cone of the 'Tiniere,
that its rate of growth was irregular. The same persons would doubtless,
had the structure of the cone been irregular, have come to the conclusion that
the rate of growth had been regular! Others will probably practice the by no
means unusual method of supposing imaginary circumstances, by means of
which to invalidate the direct inductions from positive facts. This would be
verba, non res, instead of res, non verba. Thus Professor A. Wagner, at Munich,
of course without examining the spot, found that the 4 feet of gravel, which
cover regularly the Roman stratum, might as well have been deposited in 10
or 15 minutes, instead of as many centuries.* It would have been just as
ingenious to say that a human being may grow up to manhood in 30 minutes
instead of 30 years !

At all events, the author will be delighted to abandon his results as soon as
he is shown something better.

* Sitzungsberichte der Math: Phys: Classe der Akademie in Miinchen. 8 Juni, 1861,
Reft. I.

STUDY OF HIGH ANTIQUITY. att

PROGRAMME OF THE COURSE OF LECTURES BY M. MORLOT
AT THE ACADEMY OF LAUSANNE.

InTrRoDuUcTORY LECTURE.

What is meant by the study of high antiquity—History of the science.—
MMrs. Thomson and Nilsson.—Their three ages: of the stone, of the bronze,
of the iron—The method to be followed: Ethnography; the style; associa-
tion ; superposition Chronology ; the delta of the 'Tinitre.-—End and practi-
cal use of the science.

Lecture II.

The stone age in the North.—The peat bogs in Denmark show three periods
of the forest : the Scotch fir, the oak, the beech.—Antiquities of the peat bogs.
Kjekkenmeedding (kitchen refuse) ; Plants; animals; the traces of human in-
dustry in the Kjekkenmeedding.—How flint was turned to use.

Lecture III.

The stone age in Switzerland—Pile-works or lake dwellings : their discov-
ery ; their situation ; their structure—Instruments: arms; pottery.—Plants :
flax and flaxen stuffs; corn and bread.—Wild and domestic animals.

Lecture IV.

The bronze age.-—The art of mining and smelting: copper and tin.—The
copper age in North America.—Bronze worked in the north of Europe.—Chemi-
cal examination of the antique bronze.—Gold known and worked.—The art of
casting metal_—Ornaments on the cast bronze, geometrical style-—Instruments;
arms ; trinkets—In Switzerland, pile-works of the bronze age.

LECTURE V.

The early iron age-——Meteoric iron: the primitive mode of working iron.—
Transition period from bronze to iron: Hallstatt—Silver, glass, and enamel;
glazed pottery —Coins.—The alphabet.— The North.— Switzerland : 'The Tie-
senan-find ; the Helvetians ; arms; chariots ; roads ; pile-works ; coins and in-
scriptions ; ornaments.—The geometrical style, combined with rude animal and
human figures—Monuments in Switzerland.

LEcTuRE VI.

General review.—History of civilization ; different branches of that study.—
The origin of man.—F lint instruments in diluvial gravel, with extinct species.—
The art of producing fire; its consequences.— The stone age: comparison
with the present savages ; analogies and differences; tombs and sacred stones ;
human race of the period — The bronze age: a new civilization; arts and com-
erce; tombs; religion; races; the primitive inhabitants dispossessed — The
early iron age: tombs; human sacrifices; religion; human races; domestic
animals; coining; writing —The dawn of history; the beginning of science.

Moral of the Lectures —The study of antiquity reveals the slow but steady
progress of man, as the study of geology reveals the gradual development of
our planet.

318

NORTH AMERICAN ARCH AOLOGY.

PUBLISHED BY THE SMITHSONIAN INSTITUTION.

[From the “ Natural History Review,” London.

BY JOHN LUBBOCK, F.R.S8.,’ Li. S84) AND IG.as

1. ANCIENT MONUMENTS OF THE MISSISSIPPI VALLEY, COMPRISING THE RESULTS OF

EXTENSIVE ORIGINAL SURVEYS AND EXPLORATIONS. By E. G. Squier, A.M., and
E. H. Davis, M.D.

2, ABORIGINAL MONUMENTS OF THE STATE OF NEW YORK, COMPRISING THE RESULTS
OF ORIGINAL SURVEYS AND EXPLORATIONS; WITH AN ILLUSTRATIVE APPENDIX.
By E. G. Squier, A.M.

3. THE ANTIQUITIES OF WISCONSIN, AS SURVEYED AND DESCRIBED BY I. A. Lapham.

4, THe ARCHAOLOGY OF THE UNILED STATES; OR SKETCHES, HISTORICAL AND BiBLIO-
GRAPHICAL, OF THE PROGRESS OF INFORMATION AND OPINION RESPECTING VESTIGES
oF ANTIQUITY IN THE UNITED STATES. By Samuel F. Haven.

. The four works which we have placed at the head of this article form a
part of the long series of scientific researches which have been published under
the auspices of the Smithsonian Institution. There are several other memoirs
which we ought, perhaps, to have added to our list, and especially one by Mr.
Caleb Atwater, who, according to Messrs. Squier and Davis, “deserves the
credit of being the pioneer in this department.’’ Hs researches form the first
volume of the Archzeologia Americana, which was published in 1819, and con-
tains plans and descriptions of many ancient works.

The memoir by Messrs. Squier and Davis, occupying more than three hun-
dred pages, is chiefly descriptive of ancient fortifications, enclosures, temples,
and mounds, and of the different implements, ornaments, &c., which have been
obtained from them. It is embellished with forty-eight plates, and no less than
two hundred and seven woodcuts.

In his second work, Mr. Squier confines himself to the antiquities of the State
of New York. Within these limits, however, he describes many ancient monu-
ments of various kinds, and he feels “warranted in estimating the number which
originally existed in the State at from two hundred to two hundred and fifty.”’
He comes to the conclusion, “little anticipated,” he says, “when I started upon
my trip of exploration, that the earthworks of western New York were erected
by the Iroquois, or their western neighbors, and do not possess an antiquity
going very far back of the discovery.” (szc.)

The systematic exploration of the ancient remains in Wisconsin, of which the
memoir by Mr. Lapham is the result, was undertaken by him on behalf of the
American Antiquarian Society, from whose funds the necessary expenses were
provided. The cost of the publishing, however, which, from the great number
of engravings, (fifty-five plates, besides sixty-one wood engravings,) was con-
siderable, was defrayed by the Smithsonian Institution, and the work is included
in the seventh volume of “Contributions.” As our account of the “ Animal
Mounds” will be almost entirely derived from the data furnished by Mr. Lap-
ham, we will for the moment say no more on the subject.

Mr. Haven’s work is well described in the title, and forms an interesting in-

NORTH AMERICAN ARCHAOLOGY. 319

troduction to the study of North American Archeology. He gives us compara-
tively few observations or opinions of his own; but after a careful examination
of what others have written, he comes to the conclusion that the ancient earth-
works of the United States “differ less in kind than in degree from other remains
concerning which history has not been entirely silent. They are more numerous,
more concentrated, and in some particulars on a larger scale of labor, than the
works which approach them on their several borders, and with whose various
characters they are blended. Their numbers may be the result of frequent
changes of residence by a comparatively limited population, in accordance with
a superstitious trait of the Indian nature, leading to the abandonment of places
where any great calamity has been suffered; but they appear rather to indicate
a country thickly inhabited for a period long enough to admit of the progressive
enlargement and extension of its movements.”

The last work on our list is of a very different nature. It is more general and
more ambitious. At the same time, it scarcely fulfils the promise of its title ; for
though some portions are sufliciently general, by far the larger part is purely
North American. It will form the subject of a separate notice in this Review.

The antiquities themselves fall into two great divisions: Implements (including
ornaments) and Earthworks. The Earthworks have been divided by the Ameri-
can Archeologists into seven classes: 1. Defensive enclosures; 2. Sacred and
Miscellaneous enclosures; 3. Sepulchral mounds; 4. Sacrificial mounds; 5.
Temple mounds; 6. “Animal” mounds; and 7. Miscellaneous mounds. These
classes we shall treat separately, and we can then better consider the “ mound-
_ builders” themselves.

IMPLEMENTS.

The simple weapons of bone and stone which are found in America closely
resemble those which occur in other countries. The flakes, hatchets, axes,
arrow-heads, and bone implements are, for instance, very similar to those whieh
occur in the Swiss lakes, if only we make allowance for the differences of ma-
terial. In addition to the simple forms, which may almost be said to be ubi-
quitous, there are some, however, which are more complicated. In many cases
they are perforated, as, for instance, those figured by Messrs. Squier and Davis
(I. ¢.,p. 218.) These perforated axes are generally considered in Europe to
belong to the metallic age, as also was probably the case in the New World.

At the time of the discovery of America iron was absolutely unknown to the
natives, with the exception, perhaps, of a tribe near the mouth of the La Plata,
who had arrows tipped with this metal, which they are supposed to have ob-
tained from masses of native iron. The powerful nations of Central America
were, however, in the age of bronze, while the North Americans were in a con-
dition of which we find in Europe but scanty traces—namely, in the age of cop-
per. Silver is the only other metal which has been found in the ancient tu-
muli, and that but in very small quantities. It occurs sparingly in a native
form with the copper of Lake Superior, whence, in all probability, it was de-
rived. It does not appear to have been ever smelted. From the large quantity
of galena which is found in the mounds, Messrs. Squier and Davis are disposed
to think that lead must have been used to a certain extent by the North Ameri-
can tribes; the metal itself, however, has not, I believe, yet been found.

Copper, on the other hand, occurs frequently in the tumuli, both wrought
and unwrought. The axes have a striking resemblance to the simple axes of
Europe, which contain the minimum quantity of tin; and some of the Mexican
paintings give us interesting evidence as to the manner in which they were han-
dled and used. ‘These, however, were of bronze, and had therefore been fused;
but the Indian axes, which are of pure copper, appear in all cases to-have been
worked in a cold state, which is the more remarkable, because, as Messrs. Squier
and Davis have well observed, “the fires upon the altar were sufficiently in-

320 NORTH AMERICAN ARCHAOLOGY.

tense to melt down the copper implements and ornaments deposited upon them.
The hint thus afforded does not seem to have been seized upon.”’ *

‘This is less surprising than it at first appears, if we remember that round Lake
Superior, and in some other still more northern localities, copper is found native
in large quantities, and the Indians had therefore nothing to do but to break off
pieces and hammer them into the required shape. Hearne’s celebrated journey
to the mouth of the Coppermine river was undertaken in order to examine the
locality whence the natives of that district obtained the metal. In this case it
occurred in lumps actually on the surface, and the Indians seemed to have picked
up what they could, without attempting anything that could be called mining.
Around Lake Superior, however, the case is very different. A short account of
the ancient copper-mines is given by Messrs. Squier and Davis in the work
already so often ced, by Mr. Squier in “The Aboriginal Monuments of the
State of New York,” and by Mr. Lapham,t while the same subject is treated at
considerable length by Prot. Wilson. The works appear to have been first dis-
covered in 1847, by the agent of the Minnesota Mining Company.

“Following up the indications of a continuous depression in the soil, he came
at length to a cavern where he found several porcupines had fixed their quarters
for hybernation; but detecting evidences of artificial excavation, he proceeded to
clear out the accumulated soil, and not only exposed to view a vein of copper,
but found in the rubbish numerous stone mauls and hammers of the ancient
workmen. Subsequent observations brought to light ancient excavations of
great extent, frequently from twenty-five to thirty feet deep, and scattered over
an area of several miles. ‘The rubbish taken from these is piled up in mounds
alongside ; while the trenches have been gradually refilled with the soil and de-
caying vegetable matter gathered through the long centuries since their deser-
tion; and over all, the giants of the forest have grown, and withered, and fallen
to decay. Mr. Knapp, the agent of the Minnesota Mining Company, counted
395 annular rings in a hemlock tree, which grew on one of the mounds of earth
thrown out of an ancient mine. Mr. Foster also notes the great size and age of
a pine stump, which must have grown, flourished, and died since the works
were deserted; and Mr. C. Whittlesey not only refers to living trees now
flourishing in the gathered soil of the abandoned trenches, upwards of three
hundred years old, but he adds, ‘On the same spot there are the decayed trnnks
of a preceding generation or generations of trees, that have arrived at maturity,
and fallen down from old age.’ According to the same writer, in a communica-
tion made to the American Association, at the Montreal meeting in 1857, these
. ancient works extend over a track from 100 to 150 miles in length, along the
southern shore of the lake.”

In another excavation was found a detached mass of native copper, weighing
upwards of six tons. It rested in an artificial cradle of black oak, partly pre-
served by immersion in water. Various implements and tools of the same metal
were found with it. The commonest of these are the stone mauls or hammers,
of which from one place ten cart-loads were obtained. With these were “stone
axes of large size, made of greenstone, and shaped to receive the withe-handles.”
“Some large round greenstone masses, that had apparently been used for
sledges, were also found. They had round holes bored in them to a depth of
several inches, which seemed to have been designed for wooden plugs, to which
withe-handles might be attached, so that several men could swing them with
sufficient force to break the rock and the projecting masses of copper. Some of
them were broken, and some of the projecting ends of rock exhibited marks of
having been battered in the manner here suggested.” {

“ One ‘‘cast”’ copper axe is, however, recorded as having been found in the State of New
York, but there is no evidence to show by whom it was made.

t Loe. cit., p. 74.

t Prof. W. W. Mather, in a letter to Mr. Squier, 1. ¢., p. 184.

NORTH AMERICAN ARCHA OLOGY. 321

Wooden implements are so perishable that we could not expect many of them
to have been found. Two or three wooden bowls, a trough, and some shovels
with long handles, are all that appear to be recorded.

It has often been stated that the Indians possessed some method, at present
unknown, by which they were enabled to harden the copper. This, however,
from examinations instituted by Prof. Wilson, seems to be in error. Some
copper implements, which he submitted to Prof. Crofts, were found to be no
harder than the native copper from Lake Superior. “The structure of the metal
was also highly laminated, as if the instrument had been brought to its present
shape by hammering out a solid mass of copper.”

POTTERY.

Before the introduction of metallic vessels, the art of the potter was much
more important even than it is at present. Accordingly, the sites of all ancient
habitations are marked by numerous fragments of pottery lying about; this is
as true of the ancient Indian settlements as of the Celtic towns of England, or
the Lake villages of Switzerland. These fragments, however, would generally
be those of rude household vessels, and it is principally from the tumuli that we
obtain those better-made urns and eups from which the state of the art may
fairly be inferred. Yet I know of no British sepulchral urn, belonging to the
. stone age, which has upon it a curved line. It is unnecessary to add that rep-
resentations of animals or plants are entirely wanting. They are also absent
from all articles belonging to the bronze age in Switzerland, and I might almost
say in Western Europe generally, while ornaments of curved and spiral lines
are eminently characteristic of this period. The ornamental ideas of the stone
age, on the other hand, are confined, so far as we know, to compositions of
straighter lines, and the idea of a curve does not seem to have occurred to them.
The most elegant ornaments on their vases are impressions of the finger-nail, or
of a cord wound round the soft clay.

Very different was the condition of American art. Dr. Wilson has well
pointed out that, as regards Europe, “in no single case is any attempt made to
imitate leaf or flower, bird, beast, or any simple natural object; and when, in
the bronze work of the later iron period, imitative forms at length appear, they
are chiefly the snake and dragon shapes and patterns, borrowed seemingly by
Celtic and Teutonic wanderers, with the wild fancies of their mythology, from
the far eastern cradle land of their birth.” This rule, however general, is not
quite without exceptions; witness the bronze knife, fig. 166, in the catalogue of
the Copenhagen museum. This interesting specimen has for a handle the figure
of a man, which, however, is but a poor specimen of art. Moreover, some doubt
may possibly be entertained about the age of this knife; the tip is broken off,
but the blade, as far as it goes, is quite straight in the back, a form which,
though general in the iron age, is seldom, if ever, found in knives of the bronze
age, in which the back part is always more or less curved.*

But I must not suffer myself to be led into a digression on ancient art, es-
ia as M. Morlot has been specially devoting himself to this study, and, in

is forthcoming work on the Antiquities of Mecklenbourg, will, I hope, throw
much light on the subject.

«“ Among the North American mound-builders the art of pottery attained to a
considerable degree of perfection ”” Some vases, indeed, are said to rival, ‘“in ele-
gance of model, delicacy, and finish,” the best Peruvian specimens. The ma-
terial used is a fine clay; in the more delicate specimens, pure; in the coarser
ones, mixed with pounded quartz. The art of glazing and the use of the pot-

* I except, of course, the small razor-knives, which (Copenhagen Catalogue, Nos. 171 to
175) have a totally different form. These, moreover, from the character of their ornamenta-
tion, belong probably to the close of the bronze age, if not to that of iron.

21s

322 NORTH AMERICAN ARCHAOLOGY.

ter’s wheel appear not to have been known, though that “simple approximation
to a potter’s wheel may have existed,” which consists of “a stick of wood grasped
in the hand by the middle, and turned round inside a wall of clay formed
by the other hand or by another workman.”*

Among the most characteristic specimens of ancient American pottery are .
the pipes. Some of these are simple bowls, smaller indeed, but otherwise not
unlike a common every-day pipe, from which they differ, however, in having gen-
erally no stem, the mouth having apparently been applied direct to the bowl.
Others are highly ornamented, and many are spirited representations of monsters
or of animals, such as the beaver, otter, wild cat, elk, bear, wolf, panther, rac-
coon, opossum, squirrel, manatee, eagle, hawk, heron, owl, buzzard, raven, swal-
low, parroquet, duck, grouse, and many others. The most interesting of these,
perhaps, is the manatee or lamantin, of which seven representations have been
found in the mounds of Ohio. These are no mere rude sculptures, about which
there might easily be a mistake, but “the truncated head, thick semicircular
snout, peculiar nostrils, tumid, furrowed upper lip, singular. feet or fins, and re-
markable moustaches, are all distinctly marked, and render the recognition of
the animal complete.” + This curious animal is not at present found further
north than the shores of Florida, a thousand miles away.

ORNAMENTS.

The ornaments which have been found in the mounds consist of beads, shells,
necklaces, pendants, plates of mica, bracelets, gorgets, &c. The number of
beads is sometimes quite surprising. Thus the celebrated Grave Creek mound
contained between three and four thousand shell-beads, besides about two hun-
dred and fifty ornaments of mica, several bracelets of copper, and various
articles carved in stone. ‘The beads are generally made of shell, but are some-
times cut out of bone or teeth; in form they are generally round or oblong*;
sometimes the shell of the Unio is cut and strung so as to “exhibit the convex
surface and pearly nacre of the shell.” ‘The necklaces are often made of
beads or shells, but sometimes of teeth. The ornaments of mica are thin plates
of various forms, each of which has a small hole. ‘The bracelets are of copper,
and generally encircle the arms of the skeletons, besides being frequent on the
“altars.” They are simple rings, “hammered out with more or less skill, and
so bent that the ends approach, or lap over, each other.’ 'The so-called “ gor-
gets” are thin plates of copper, always with two holes, and probably, therefore,
worn as badges of authority.

EARTHWORKS.

Defensive enclosures —The works belonging to the first class “usually oc-
cupy strong natural positions,” and as a fair specimen of them we may take the
Bourne calle enclosure in Ross county, Ohio. “This work,” say Messrs. Squier
and Davis (Ll. ¢., p. 11,) “ occupies the summit of a lofty detached hill, twelve
miles westward from the city of Chillicothe, near the village of Bourneville.
“The hill is not far from four hundred feet in perpendicular height; and is re-
markable, even among the steep hills of the west, for the general abruptness
of its sides, which at some points are absolutely inaccessible”? * * * *
“The defences consist of a wall of stone, which is carried round the hill a little
below the brow; but at some places it rises, so as to cut off the narrow spurs,
and extends across the neck that connects the hill with the range beyond.”
It. must not, however, be understood that anything like a true wall now exists ;
the present appearance is rather what might have been “expected from the
falling outwards of a wall of stones, placed, as this was, upon the declivity of

* Squier and Davis, l. ¢., p. 195. t Squier and Davis, l. ¢., p. 252.

NORTH AMERICAN ARCHA OLOGY. 323

a hill.’ Where it is most distinct it is from fifteen to twenty feet wide by three
or four in height. The area thus enclosed is about one hundred and forty acres,
and the wall is two miles and a quarter in length. The stones themselves vary
much in size, and Messrs. Squier and Davis suggest that the wall may originally
have been about eight feet high, with an equal base. At present, trees of the
largest size are growing upon it. On a similar work, known as “ Fort Hill,”
Highland county, Ohio, Messrs. Squier and Davis found a splendid chestnut
tree, which they suppose to have been six hundred years old. “If,” they say,
“to this we add the probable period intervening from the time of the building
of this work to its abandonment, and the subsequent period up to its invasion
by the forest, we are led irresistibly to the conclusion that it has an antiquity of
at least one thousand years. But when we notice, all around us, the crumbling
trunks of trees, half hidden in the accumulating soil, we are induced to fix on
an antiquity still more remote.”

The enclosure known as Clark’s work, in Ross county, Ohio, is one of the
largest and most interesting. It consists of a parallelogram, two thousand eight
hundred feet by eighteen hundred, and enclosing about one hundred and eleven
acres. To the right of this, the principal work is a perfect square, containing
an area of about sixteen acres. Each side is eight hundred and fifty feet in
length, and in the middle of each is a gateway thirty feet wide, and covered by
asmall mound. Within the area of the great work are several smaller mounds
and enclosures; and it is estimated that not less than three millions of cubic
feet of earth were used in this great undertaking. °

It has also been observed that water is almost invariably found within or
close to these enclosures.

Sacred and miscellaneous enclosures—If the purpose for which the works
belonging to the first class were erected is very evident, the same cannot be
said for those which we have now to mention. ‘That they were not intended
for defence is inferred by Messrs. Squier and Davis from their small size, from
the ditch being inside the embankment, and from their position, which is often
completely commanded by neighboring heights.

Dr. Wilson also (vol. i, p. 324) follows Sir R. C. Hoare in considering the
position of the ditch as being a distinguishing mark between military and
religious works. But Catlin expressly tells us that in the Mandan village
which he describes, the ditch was on the inner side of the embankment, and
the warriors were thus sheltered while they shot their arrows through the
stockade. We see, therefore, that, in America at least, this is no reliable guide.

While, however, the defensive earthworks occupy hill-tops, and other situ-
ations most easy to defend, the so-called sacred enclosures are generally found
on “the broad and level river bottoms, seldom occurring upon the table-lands,
or where the surface of the ground is undulating or broken.” They are usually
square or circular in form, a circle being often combined with one or two
squares. ‘Occasionally we find them isolated, but more frequently in groups.
The greater number of the circles are of small size, with a nearly uniform
diameter of two hundred and fifty or three hundred feet, and invariably have
the. ditch interior to the wall.”’ Some of the circles, however, are much larger,
enclosing fifty acres or more. The squares or other rectangular works never
have a ditch, and the earth of which they are composed appears to have been
taken up evenly from the surface, or from large pits in the neighborhood.
They vary much in size; five or six of them, however, are “exact squares,
each side measuring one thousand and eighty feet—a coincidence which could
not possibly be accidental, and which must possess some significance.” The
circles also, in spite of their great size, are perfectly round, so that the Ameri-
can archeologists consider themselves justified in concluding that the mound-
builders must have had some standard of measurement, and some means of
determining angles.

324 NORTH AMERICAN ARCHAOLOGY.

The most remarkable group is that near Newark, in the Scioto valley, which
covers an area of four square miles! A plan of these gigantic works is given
by Messrs. Squier and Davis, and another, from a later survey, by Mr. Wilson.
They consist of an octagon, with an area of fifty, a square occupying twenty
acres, two large circles occupying, respectively, thirty and twenty acres. From
the octagon an avenue formed by parallel walls exteads southwards for two
miles and a half; there are two other avenues which are rather more than a
mile in length, one of them connecting the octagon with the square.

Besides these, there are various other embankments and small circles, the
greater number about eighty feet in diameter, but some few much larger. T’he
walls of these small circles, as well as those of the avenues and of the irregular
portions of the works generally, are very slight, and for the most part about
four feet in height. The other embankments are much more considerable; the
walls of the large circle are even now twelve feet high with a base of fifty feet,
and an interior ditch seven feet deep and thirty-five in width. At the gateway,
however, they are still more imposing; the walls being sixteen feet high, and
the ditch thirteen feet deep. The whole area is covered with “gigantic trees
of a primitive forest ;” and, say Messrs. Squier and Davis, “in entering the
ancient avenue for the first time, the visitor does not fail to experience a sensa-
tion of awe, such as he might feel in passing the portals of an Kgyptian temple,
or in gazing upon the silent ruins of Petra of the desert.”

The city of Circleville takes its name from one of these embankments, which,
however, is no more remarkable than many others. It consists of a square and
a circle, touching one another; the sides of the square being about nine hun-
dred feet in length, and the circle a little more than a thousand feet in diameter.
The square had eight doorways, one at each angle, and one in the middle of
each side, every doorway being covered by a mound. The circle was peculiar
in having a double embankment. This work, alas! has been entirely destroyed;
and many others have also disappeared, or being gradually obliterated by the
plough. Under these circumstances, we read with pleasure that “ the directors
of the Ohio Land Company, when they took possession of the country at the
mouth of the Muskingum river in 1788, adopted immediate measures for the
preservation of these monuments. To their credit be it said, one of their
earliest official acts was the passage of a resolution, which is entered upon the
journal of their proceedings, reserving the two truncated pyramids and the
great mound, with a few acres attached to each, as public squares.” Such en-
lightened conduct deserves the thanks of archeologists, and we sincerely hope
that the company has prospered.

Both as being the only example of an enclosure yet observed in Wisconsin,
and also as having in many respects a great resemblance to a fortified town,
the ruins of Aztalan are well worthy of attention. They are situated on the
west branch of Rock river, and were discovered in 1836 by N. F. Hyer, esq.,
who surveyed them hastily, and published a brief description, with a figure, in
the ‘“ Milwaukie Advertiser.” In “ Silliman’s American Journal,” No XLIYV, is
a paper on the subject by Mr. Taylor, from which was derived the plan and the
short account given by Messrs. Squier and Davis.* The most complete de-
scription is contained in Mr. Lapham’s “Antiquities of Wisconsin.”t ‘The name
“Aztalan” was given to this place by Mr. Hyer, because the Aztecs had a
tradition that they originally came from a country to the north, which they
called Aztalan. It is said to be derived from two Mexican words, Atl, water,
and An, near. “The main feature of these works is an enclosure of earth
(not brick, as has been erroneously stated) extending around three sides of an
irregular parallelogram ;” the river “forming the fourth side on the east. The
space thus enclosed is seventeen acres and two-thirds. The corners are not

“E.G, ps tol. TP. 41.

NORTH AMERICAN ARCHAOLOGY. 325

rectangular, and the embankment or ridge is not straight.” “The ridge form-
ing the enclosure is 631 feet long at the north end, 1,419 feet long on the west
side, and 700 feet on the south side; making a total length of wall of 2,750
feet. The ridge or wall is about 22 feet wide, and from one foot to five in
height. The wall of earth is enlarged on the outside, at nearly regular dis-
tances, by mounds of the same material. They are called buttresses, or
bastions ; but it is quite clear that they were never intended for either’ the
one or the other. They vary from sixty-one to ninety-five feet apart, the
mean distance being eighty-two feet. Near the southwest angle are two out-
works, constructed in the same way as the main embankment.

In many places the earth forming the walls appears to have been burnt.
“Trregular masses of hard reddish clay, full of cavities, bear distinct impres-
sions of straw, or rather wild hay, with which they had been mixed before
burning.” “This is the only foundation for calling these ‘brick walls.’ The
‘bricks’ were never made into any regular form, and it is even doubtful whether
the burning did not take place in the wall after it was built.” Some of the
mounds, or buttresses, though forming part of an enclosure, were also used for
sepulchral purposes, as was proved by their containing skeletons in a sitting
posture, with fragments of pottery. The highest point inside the enclosure is
at the southwest corner, and is “ occupied by a square truncated mound, which

* * * presents the appearance of a pyramid, rising by successive steps like the
gigantié structures of Mexico.” “At the northwest angle of the enclosure is
another rectangular, truncated, pyramidal elevation, of sixty-five feet level area
at the top, with remains of its graded way, or sloping ascent, at the southwest
corner, leading also towards a ridge that extends in the direction of the river.’

Within the enclosure are some ridges akout two feet high, and connected
with them are several rings, or circles, which are supposed to be the remains of
mud houses. ‘ Nearly the whole interior of the enclosure appears to have been
either excavated or thrown up into mounds and ridges; the pits and irregular
excavations being quite numerous over much of the space not occupied by
mounds.” In these excavations and ridges, also, we should be inclined to see
the ruins of houses. Some years ago a skeleton was found in one of the
mounds wrapped apparently in cloth of open texture, “like the coarsest linen
fabric ;” but the threads were so entirely rotten, as to make it quite uncertain
of what material they were made.

The last Indian occupants of this interesting locality had no tradition as to
the history or the purpose of these earthworks.

Among the northern tribes of existing Indians there do not appear to be any
earthworks corresponding to these so-called sacred enclosures. “No sooner,
however, do we pass to the southward, and arrive among the Creeks, Natchez,
and affiliated Floridian tribes, than we discover traces of structures which, if
they do not entirely correspond with the regular earthworks of the west, never-
theless seem to be somewhat analogous to them.”* These tribes, indeed, ap-
pear to have been more civilized than those to the north, since they were
agricultural in their habits, lived in considerable towns, and had a systematized
religion, so that, in fact, they must have occupied a position, as well economically
as geographically, intermediate between the powerful monarchies of Central
America and the hunting tribes of the north. The “structures” to which Mr.
Squier alludes are described by him both in his “ Second Memoir,” and also in
the “Ancient Monuments of the Mississippi valley,” (p. 120.) The “Chunk
Yards,” now or lately in use among the Creeks, and which have only recently
been abandoned among the Cherokees, are rectangular areas, generally oceupy-
ing the centre of the town, closed at the sides, but with an opening at each end.
They are sometimes from six to nine hundred feet in length, being largest in the
a Re 5 he st Lh seer seed ds ee aie) Wil

* Squier, l. c., p. 186.

326 NORTH AMERICAN ARCHAOLOGY.

older towns. ‘The area is levelled and slightly sunk, being surrounded by a low
bank formed of the earth thus obtained. In the centre is a low mound, on
which stands the Chunk Pole, to the top of which is some object which serves
as a mark to shoot at. Near each corner at one end is a small pole about
twelve feet high; these are called the “ slave-posts,” because in the “ good old
times’? captives condemned to the torture were fastened to them. The name
“Chunk Yard” seems to be derived from an Indian game ealled “ Chunke,”
which was played in them.

At one end of and just outside this area stands generally a circular eminence,
with a flat top, upon which is elevated the great Council House.

At the other end is a flat-topped, square eminence, about as high as the cir-
cular one just mentioned; “upon this stands the public square.”

These and other accounts given by early travellers among the Indians
certainly throw much light on the circular and square enclosures ; but some of
those, classed by Messrs. Squier and Davis under this head, seem to us to be
the slight fortifications which surrounded villages, and were undoubtedly
crowned by stockades. We have already seen that the position of the ditch is
in reality no argument against this view; nor does the position of the works
seem conclusive, if we suppose that the works were intended less to stand a
regular siege than to guard against a sudden attack.

Sepulchral mounds—The sepulchral mounds are very numerous. “'To say
that they are innumerable, in the ordinary sense of the term, would be no exag-
geration. ‘hey may literally be numbered by thousands and tens of thousands.”
They vary from six to eight feet in height; generally stand outside the enclo-
sures; are often isolated, but often also in groups; they are usually round, but
sometimes elliptical or pear-shaped. ‘They cover generally a single skeleton,
which, however, is often burnt. Occasionally there is a stone cist, but urn burial
also prevailed to considerable extent, especially in southern States. The con-
tracted position of the corpse seems to be as usual as in the more ancient burials
of Europe. Implements both of stone and metal occur frequently ; but while
personal ornaments, such as bracelets, perforated plates of copper, beads of
bone, shell, or metal, and similar objects, are very common, weapons are but
rarely found; a fact which, in the opinion of Dr. Wilson, “indicates a totally
different condition of society and mode of thought” from that of the present
Indian. Plates of mica are very generally present, and in some cases the
skeleton is entirely covered by them.

What now is the “idea” implied in these often gigantic tumuli, and in the
disposition of the corpse? The reason suggested by M. Troyon for the con-
tracted position of the body has already been mentioned in this journal. Dr.
Wilson appears to regard the tumulus as a simple development of that little
heap of earth “ displaced by interment, which still to thousand, suffices as the
most touching memorial of the dead.’’ Probable as these suggestions may
appear, we confess that if we were to express an opinion we should lean rather
to the opinion of the illustrious Swedish antiquary, Prof. Nillson, and imagine
that the grave was but an adaptation, a copy, or a development of a dwelling-
place. Unable to imagine a future altogether different from the present, or a
world, quite unlike our own, primitive nations seem always to have buried with
their dead those things which in life they valued most; with ladies their orna-
ments; with chiefs their weapons, and sometimes also their wives. hey burned
the house with its owner; the grave was literally the dwelling of the dead.
According to Prof. Nillson, when a great man died he was placed in his favorite
seat, food and drink were arranged before him, his weapons were placed at hand,
and his house was closed, sometimes forever, sometimes to be opened once more,
when his wife or his childgen had joined him in the land of spirits. The
ancient tumuli in northern Europe, which never contain metal, consist usually
of a passage leading into a central vault, in which the dead “sit.” At God-

NORTH AMERICAN ARCHAZOLOGY. 327

havn, in the year 1830, a grave of this kind was opened, and numerous skeletons
were found sitting on low seats around the walls, each with their weapons and
ornaments. ‘The description given by Captain Graah of the Eskimo “winter-
house,”’ and Scoresby’s account of those belonging to the Greenlanders, agree
closely with these graves, even to the fact that the passage points generally to
the south or east, but never to the north. In a few cases tumuli have been
examined which contained weapons, implements, ornaments, pottery, &c., but
no human bones; in short, every indication of life, but no trace of death. Ernan
also tells us that the graves of 'Tartars resemble their dwellings, a statement
which Nillson apparently considers to be true of all primitive nations. In the
Sulu islands it is the custom to desert any house in which a great man has died,*
and Captain Cook mentions his having seen at Mooa certain houses raised on
mounds, ia which he was told “the dead had been buried.”

Certain small tumuli found in America have already been regarded as the
remains of mud villages. Mr. Dillet has examined and described some small
tumuli observed by him in Missouri. He dug into several, but never succeeded
in finding anything except coals and a fay pieces of rude pottery, whence he
concluded that they were the remains of mud houses.t The Mandans, Mina-
tarees, and some other tribes, also built their huts of earth, resting on a frame-
work of wood.

On the other hand, there are some tumuli to which it would seem that this
explanation is quite inapplicable, and which are full of human remains. This
was long supposed to be the case with the great Grave Creek Mound, which,
indeed, was positively described by Atwater§ to be fuil of human remains. This
has turned out to be an error, but the statement is not the less true as regards
other mounds. In conjunction with them may be mentioned the “bone pits,”
many of which are described by Mr. Squier.|| ‘One of these pits, discovered
some years ago in the town of Cambria, Niagara county, was estimated to con-
tain the bones of several thousand individuals. Another which I visited in the
town of Clarence, Erie county, contained not less than four hundred skeletons.”
A tumulus described by Mr. Jefferson in his “Notes on Virginia’’ was estimated
to contain the skeletons of a thousand individuals, but in this case the number
was perhaps exaggerated.

The description given by various old writers of the solemn “Festival of the
Dead” satisfactorily explains these large collections of bones. It seems that
every eight or ten years the Indians met at some place previously chosen ; that
they dus up their dead, collected the bones together, and laid them in one ‘com-
mon ar ial place, depositing with them fine aleing and other valuable articles.

Sacrificial mounds —“The name of sacrificial mounds,” says Dr. Wilson,
“has been conferred on a class of ancient monuments, altogether peculiar to the
New World, and highly illustrative of the rites and customs of the ancient races
of the mounds. This remarkable class of mounds has been very carefully
explored, and their most noticeable characteristics are, their almost invariable
occurrence within enclosures; their regular construction in uniform layers of
gravel, earth, and sand, disposed alternately in strata conformable to the shape
of the mound; and their covering a symmetrical altar of burnt clay or stone, on
which are deposited numerous relics, in all instances exhibiting traces, more or
less abundant, of their having been exposed to the action of fire.” The so-called
“altar” is a basin, or table, of burnt clay, carefully formed into a symmetrical
form, but varying much both in shape and size. Some are round, some elliptical,
and others, squares or parallelograms, while in size they vary from two feet to

* St, John’s Life in the Forests of the Far East, Vol. ii, p. 217.

t Smithsonian Contributions, Vol. i, p. 136.

$ Archeeologia Americana, Vol. i, p. 223.

§ See also Lapham, G., p.o0e

| L. ¢., p. 25, 56, 57, 68, 71, 73, 106, 107. Squier and Davis, 1. ¢c., p. 118, &c.

328 NORTH AMERICAN ARCHAZOLOGY.

fifty feet by twelve or fifteen. The usual dimensions, however, are from five to
eight feet. They are almost always found within sacred enclosures; of the
whole number examined by Messrs. Squier and Davis, there were only four
which were exterior to the walls of enclosures, and these were but a few rods
distant from them.

The “altar” is always on alevel with the natural soil, and bears traces of
long-continued heat; in one instance, where it appears to have been formed of
sand, instead of clay, the sand for the depth of two inches is discoloured as if
fatty matter of some sort had been burned on it. In this case a second deposit
of sand had been placed on the first, and upon this stones a little larger than a
hen’s egg were arranged so as to form a pavement, which strongly reminds us
of the ancient hearths in the Danish Kjkikenméddings.

In a few instances traces of timber were found above the altar. Thus in one
of the twenty-six tumuli forming the “Mound City,” on the Scioto river, were
found a number of pieces of timber four or five feet long, and six or eight inches
thick. ‘These pieces had been of nearly uniform length; and this circumstance,
joined to the position in which they occurred in respect to each other and to the
altar, would almost justify the inference that they had supported some funeral
or sacrificial pile.’* The contents of these mounds vary very much. 'The one
Just mentioned contained a quantity of pottery and many implements of stone
and copper, all of which had been subjected to a strong heat. The pottery
may have formed a dozen vessels of moderate size. The copper articles
consisted of two chisels, and about twenty thin strips. About fifty or a
hundred stone arrow-heads, some flakes, and two earved pipes, completed the
list of articles found in this interesting tumulus. In another mound nearly two
hundred pipes were buried. Generaily speaking, the deposit is homogeneous.
“That is to say, instead of finding a large variety of relics, ornaments, weapons,
and other articles, such as go to make up the possessions of a barbarian dig-
nitary, we find upon one altar pipes only, upon another a single mass of galena,
while the next one has a quantity of pottery, or a collection of spear-heads, or
else is destitute of remains, except perhaps a thin layer of carbonaceous material.
Such could not possibly be the case upon the above hypothesis, for the spear, the
arrows, the pipe, and the other implements, and personal ornaments of the dead,
would then be found in connexion with each other.”’t

This conclusion does not seem to us altogether satisfactory; and although
these altar-containing mounds differ in so many respects from the above-described
tumuli, we still feel disposed to regard them as sepulchral rather than sacrificial.
Not having, however, had the advantage of examining them for ourselves, we
throw this out as a suggestion, rather than express it as an opinion. We confess
that we feel much difficulty in understanding why “altars” should be covered up
in this manner; we can call to mind no analogous ease. On the other hand, if
Prof. Nillson’s suggestion in relation to the ancient tumuli be correct, the long-
continued fire will offer no difficulty; while the wooden constructions and the
burnt bones will all be explicable on the hypothesis that we have before us a
sepulchre, rather than a temple.

Nor does the “homogeneousness”’ of the deposits found in these mounds
appear so decisive to us as to Messrs. Squier and Davis. Take, for instance, the
cases in which pipes are found. The execution of these is so good that “pipe-
carving” was no doubt a profession; the division of labor must have already
begun. Exactly the same feeling which would induce them to bury weapons
with the dead hunter, in order that he might supply himself with food in Hades
as on earth; that feeling which among some ancient nations suggested the
placing of money in the grave, would account not only for the presence of these
pipes, but also for their number. The hunter could use but few weapons, and

* Squier and Davis, 1. ¢., p. 151. t Ditto, p. 160.

NORTH AMERICAN ARCHAOLOGY. 329

must depend for success mainly on his strength and skill; whereas the pipe-
seller, if he could use a pipe at all in the grave, might render his whole stock in
trade available.

Tf, therefore, “the accumulated carbonaceous matter, like that formed by the
ashes of leaves or grass,’’ which suggests to Prof. Wilson “the graceful offerings
of the first fruits of the earth, so consonant to the milder forms of ancient sacrifice
instituted in recognition of the Lord of the Harvest,” seems to us only the frame-
work of a house, or the material of a funeral pyre; on the other hand, we avoid
the conclusion to which he is driven, that on “the altars of the mould-builders,
human sacrifices were made; and that within their sacred enclosures were
practised rites not less hideous than those which characterized the worship
which the ferocious Aztecs are affirmed to have regarded as most acceptable to
their sanguinary gods,”

Temple mounds—The class of mounds, called by Messrs. Squier and Davis
“Temple mounds,” ‘are pyramidal structures, truncated, and generally having
graded avenues to their tops. In some instances they are terraced, or have
successive stages. But whatever their form, whether round, oval, octangular,
square, or oblong, they have invariably flat or level tops, of greater or less area.”
These mounds much resemble the Teocallis of Mexico, and had probably a
similar origin. ‘They are rare in the north, though examples occur even as far
as Lake Superior, but become more and more numerous as we pass down the
Mississippi, and especially on approaching the Gulf, where they constitute the
most numerous and important portion of the ancient remains. Some of the
largest, however, are situated in the north. One of the most remarkable is at
Cahokia, in Hlinois. This gigantic mound is stated to be seven hundred feet
long, jive hundred feet wide at the base, and ninety feet in height. Its solid
contents have been roughly estimated at twenty millions of cubic feet.

Probably, however, these mounds were not used as temples only, but also as
sites for dwellings, especially for those of the chiefs. We are told that among
the Natchez Indians “the temples and the dwellings of the chiefs were raised
upon mounds, and for every new chief a new mound and dwelling were con-
structed.” Again: Garcilego de la Vega, in his History of Florida, quoted by
Mr. Haven,* says, “The town and house of the cacique of Osachile are similar
to those of all other caciques in Florida, and, therefore, it seems best to give one
description that will apply generally to all the capitals, and all the houses of
the chiefs in Florida. I say, then, that the Indians endeavor to place their
towns upon elevated places; but because such situations are rare in Florida, or
that they find a difficulty in procuring suitable materials for building, they raise
eminences in this manner. ‘They choose a place to which they bring a quantity
of earth, which they elevate into a kind of platform two or three pikes in height,
(from eighteen to twenty-five feet,) of which the flat top is capable of holding
ten or twelve, fifteen or twenty houses, to lodge the cacique, his family, and
suite.”

Animal mounds.—Not the least remarkable of the American antiquities are
the animal mounds, which are principally, though not exclusively, found in
Wisconsin. In this district “thousands of examples occur of gigantic basso-
relievos of men, beasts, birds, and reptiles, all wrought with persevering labor
on the surface of the soil,” while enclosures and works of defence are almost
entirely wanting, the “ancient city of Aztalan” being, as is supposed, the only
example of the former elass.

The “ Animal Mounds” were first observed by Mr. Lapham in 1836, and
described in the newspapers of the day, but the first account of them in any
scientific journal was that by Mr. R. C. Taylor, in the American Journal of
Science and Art, for April, 1838. In 1843 a longer memoir, by Mr. 8. Taylor,

* ZL. c.,\p. 57.

330 NORTH AMERICAN ARCHAOLOGY.

appeared in the same journal. Professor J. Locke gave some account of them
in a “Report on the Mineral Lands of the United States,” presented to Con-
gress in 1840. Messrs Squier and Davis devoted to the same subject a part of
their work on the ‘“ Ancient Monuments of the Mississippi Valley ;” and finally,
the seventh volume of the Smithsonian Contributions contains the work, by Mr.
Lapham, which we have placed at the head of this article. Dr. Wilson does
not appear to have made any original observations on this branch of the subject,
but in a chapter on “Symbolic Mounds” he has given an interesting summary
derived from these sources.

Mr. Lapham gives a map showing the distribution of these curious earth-
works. ‘They appear to be most numerous in the southern counties of Wiscon-
sin, and extend from the Mississippi to Lake Michigan, following generally the
courses of the river, and being especially numerous along the great Indian trail
or war-path from Lake Michigan, near Milwaukie, to the Mississippi, above
Prairie du Chien. 'This, however, does not prove any connexion between the
present Indians and the mounds, as the same line has been adopted as the route
of the United States military road.

The mounds themselves not only represent animals, such as men, buffaloes,
elks, bears, otters, wolves, raccoons, birds, serpents, lizards, turtles, and frogs,
but also some inanimate objects ; if at least the American archeologists are right
in regarding some of them as crosses, tobacco-pipes, &c.

Many of the representations are spirited and correct, but others, probably
through the action of time, are less definite; one, for instance, near the village
of Muscoda, may be either “a bird, a bow and arrow, or the human figure.’
Their height varies from one to four feet, sometimes, however, rising to six feet;
and as a “regular elevation of six inches can be readily traced upon the level
prairies” of the west, their outlines are generally distinctly defined where they
occupy favorable positions. It seems probable that many of the details have
disappeared under the action of rain and vegetation. At present a “man” con-
sists generally of a head and body, two long arms and two short legs, no other
details being visible. The “birds” differ from the “men” principally in the
absence of legs. The so-called “lizards,” which are among the most common
forms, have a head, two legs, and a long tail; the side view being represented,
as is, indeed, the case with most of the quadrupeds.

One remarkable group in Dale county, close to the Great Indian trail, con-
sists of a man with extended arms, seven more or less elongated mounds, one
tumulus and six quadrupeds. The length of the human figure is one hundred
and twenty-five feet, and it is one hundred and forty feet from the extremity of
one arm to that of the other. ‘The quadrupeds vary from ninety to a hundred
and twenty-six feet in length.

At Waukesha are a number of mounds, tumuli, and animals, including several
“lizards,” a very fine “bird,” and a magnificent “turtle.” “This, when first
observed, was a very fine specimen of the art of mound-building, with its grace-
ful curves, the feet projecting back and forward, and the tail, with its gradual
slope, so acutely pointed, that it was impossible to ascertain precisely where it
terminated, ‘The body was fifty-six feet in length, and the tail two hundred
and fifty ; the height six feet.” This group of mounds is now, alas! covered
with buildings. “A dwelling-house stands on the body of the turtle, and a
Catholic church is built upon the tail.”

“But,” says Mr. Lapham, “the most remarkable collection of lizards and
turtles yet discovered is on the school section, about a mile and a half southeast
from the village of Pewaukee. This consists of seven turtles, two lizards, four
oblong mounds, and one of the remarkable excavations before alluded to. One
of the turtle mounds, partially obliterated by the road, has a length of four hun-
dred and fifty feet; being nearly double the usual dimensions. ‘Three of them
are remarkable for their curved tails, a feature here first observed.”

NORTH AMERICAN ARCHAOLOGY. 301

In several places a very curious variation occurs. The animals, with the
usual form and size, are represented not in relief, but in intaglio; not by a mound,
but by an excavation.

The few “animal mounds” which have been observed out of Wisconsin differ
in many respects from the ordinary type. Near Granville, in Ohio, on a high
spur of land, is an earthwork known in the neighborhood as the ‘‘ Alligator.”
It has a head and body, four sprawling legs, and a curled tail. The total length
is two hundred and fifty feet ; the breadth of the body forty feet; and the length
of the legs thirty-six feet. “The head, shoulders, and rump, are more elevated
than the other parts of the body, an attempt having evidently been made to pre-
serve the proportions of the object copied.” The average height is four fect, at
the shoulders six. Still more remarkable, however, is the great serpent in Adams
county, Ohio. It is situated on a high spur of land, which rises a hundred and
fifty feet above Brush creek. “Conforming to the curve of the hill, and oceupy-
ing its very summit, is the serpent, its head resting near the point, and its body
winding back for seven hundred feet, in graceful undulations, terminating in a
triple coil at the tail. The entire length, if extended, would be not less than one
thousand feet. The accompanying plan, laid down from accurate survey, can
alone give an adequate conception of the outline of the work, which is clearly
and boldly defined, the embankment being upwards of five feet in height by
thirty feet base at the centre of the body, but diminishing somewhat toward the
head and tail. The neck of the serpent is stretched out, and slightly curved,
and its mouth is opened wide, as if in the act of swallowing or ejecting an oval
figure, which rests partially within the distended jaws. This oval is formed by
an embankment of earth, without any perceptible opening, four feet in height,
and is perfectly regular in outline, its transverse and conjugate diameters being
one hundred and sixty and eighty feet respectively.”

When, why, or by whom these remarkable works were erected, as yet we
know not. ‘The present Indians, though they look upon them with reverence,
can throw no light upon their origin. Nor do the contents of the mounds them-
selves assist us in this inquiry. Several of them have been opened, and “in the,
process of grading the streets of Milwaukie” “many of the mounds were entirely
removed,” but the only result has been to show that they are not sepulchral,
and that, excepting by accident, they contain no implement or ornament.

Under these circumstances speculation would be useless ; we can but wait and
hope that time and perseverance may solve the problem, and explain the nature
of these remarkable and mysterious monuments.

INSCRIPTIONS.

There is one class of objects which I have not yet mentioned, and which yet
ought not to be left entirely unnoticed.

The most remarkable of these is the celebrated Dighton Rock, on the east
bank of the Taunton river. Its history, and the various conclusions which have
been derived from it, are very amusingly given by Dr. Wilson.* In 1783 the
Rev. Ezra Stiles, D.D., president of Yale College, when preaching before the
governor of the State of Connecticut, appealed to this rock, inscribed, as he be-
lieved, with Pheenician characters, for a proof that the Indians were descended
from Canaan, and were, therefore, accursed. Count de Gebelin regarded it as a
Carthaginian inscription. In the eighth volume of the “ Archzologia ” Colonel
Vallency endeavors to prove that it is Siberian; while certain Danish antiquaries
regarded it as Runie, and thought that they could read the name “ 'Thorfinn,”
“with an exact, though by no means so manifest, enumeration of the associates
who, according to the Saga, accompanied Karlsefne’s expedition to Vinland,
in A.D. 1007.” Finally, Mr. Schoolcraft submitted a copy of it to Chingwauk

* Vol. ii, p. 172.

332 NORTH AMERICAN ARCHZOLOGY.

an intelligent Indian chief, who “interpreted it as the record of an Indian triumph
over some rival native tribe,” but without, we believe, offering any opinion as to
its antiquity.

In the “Grave Creek Mound” was found a small oval disk of white sandstone,
on which were engraved twenty-two letters. Mr. Schoolcraft, who has especially
studied this relic, finally concludes, after corresponding with many American
and European archeologists, according to Dr. Wilson, that of these twenty
letters, four corresponded with ancient Greek,* four with the Etruscan, five with
the old Northern Runes, six with the ancient Gaelic, seven with the old Erse,
ten with the Pheenician, fourteen with the Anglo-Saxon, and sixteen with the
Celtiberic; besides which possibly equivalents may be found in the old Hebrew.
“Tt thus appears that this ingenious little stone is even more accommodating
than the Dighton Rock in adapting itself to all conceivable theories of ante-
columbian colonization.” A stone of such doubtful character could prove little
under any circumstances; but it must also be mentioned that “Dr. James W.
Clemens communicated to Dr. Morton all the details of the exploration of the
Grave Creek Mound; * * * without any reference to the discovery of the
inscribed stone. Nor was it till the excavated vault had been fitted up by its
proprietor for exhibition, to all who cared to pay for the privilege of admission,
that the marvellous inscription opportunely came to light to add to the attrae-
tions of the show.”

One or two other equally doubtful cases are upon record ; but upon the whole
we may safely assert that there is no reason to suppose that the nations of
America had developed for themselves anything corresponding to an alphabet.
The picture-writing of the Aztecs and the Quipa of the Peruvians was replaced
among the North American Indians by the “wampum.” ‘This curious substi-
tute for writing consisted of variously-colored beads generally worked upon
leather. One very interesting example is the belt of wampum “delivered by
the Lenni Lenape Sachems to the founder of Pennsylvania, at the great treaty,
under the elm-tree at Shachamox in 1682.” It is still preserved in the collee-
tion of the Historical Society at Philadelphia, and consists of “eighteen strings
of wampum, formed of white and violet beads worked upon leather thongs,”
the whole forming a belt twenty-eight inches long and two and a half broad.
“On this five patterns are worked in violet beads on a white ground, and in the
centre Penn is represented taking the hand of the Indian Sachem.” ‘The large
number of beads found in the tumuli were, perhaps, in a similar manner intended
to commemorate the actions and virtues of the dead.

THE MOUND-BUILDERS.

Just as the wigwam of the recent Mandan consisted of an outer layer of
earth supported on a wooden framework, so also, in the ancient sepulchral tumuli,
the body was protected only by beams and planks, so that when these latter
decayed, the earth sank in and crushed the skeleton within. Partly from this
cause, and partly from the habit of burying in ancient tumuli, which makes it
sometimes difficult to distinguish the primary from secondary interments, it hap-
pens that from so many thousand tumuli we have only three skulls which indis-
putably belong to the ancient race. ‘These are decidedly brachycephalic ; but
it is evident that we must not attempt to build much upon so slight a basis.

No proof of a knowledge of letters, no trace of a burnt brick have yet been
discovered, and, so far as we may judge from their arms, ornaments, and pottery,
the mound-builders closely resembled some at least of the recent Indian tribes ;
and the earthworks resemble in form, if they differ in magnitude from those still,
or until lately, in use. Yet this very magnitude is suflicient to show that, at
some early period, the great river valleys of the United States must have been

* Vol. ii, p. 180.

NORTH AMERICAN ARCHAOLOGY. 333

very much more densely populated than they were when first discovered by
Europeans. ‘The immense number of small earthworks, and the mounds, “ which
may be counted by thousands and tens of thousands,” might indeed be supposed
to indicate either a long time or a great population; but in other cases we have
no such alternative. ‘The Newark constructions ; the mound near Florence, in
Alabama, which is forty-five feet in height by four hundred and forty feet in
circumference at the base, with a level area at the summit of one hundred and
fifty feet in circumference; the still greater mound on the Etowah river, also in
Alabama, which has a height of more than seventy-five feet, with a circumfer-
ence of twelve hundred feet at the base, and one hundred and forty at the sum-
mit; the embankments at the mouth of the Scioto river, which are estimated to
be twenty miles in length; the great mound at Selsertown, Mississippi, which
covers six acres of ground; and the truncated pyramid at Cahokia, to which we
have already alluded; these works, and many others which might have been
quoted, indicate, we think, a population large and stationary, for which hunting
cannot have supplied enough food, and which must, therefore, have relied in a
great measure upon agriculture for its support. ‘There is not,” says Messrs.
Squier and Davis, “and there was not in the sixteenth century, a single tribe of
Indians (north of the semi-civilized nations) between the Atlantic and the Pacific,
which had means of subsistence sufficient to enable them to apply, for such pur-
poses, the unproductive labor necessary for the work ; nor was there any in such
a social state as to compel the labor of the people to be thus applied.” We know
also that many, if not most of the Indian tribes, still cultivated the ground to a
certain extent, and there is some evidence that even within historic times this
was more the case than at present. Thus De Nonville estimates the amount of
Indian corn destroyed by him in four Seneca villages at 1,200,000 quarters.

Mr. Lapham* has brought forward some ingenious arguments for thinking that
the forests of Wisconsin were at no very distant period much less general than
at present. In the first place, the largest trees are probably not more than five
hundred years old; and large tracts are now covered with “young trees, where
there are no traces of antecedent growth.”

Again, every year many trees are blown down, and frequent storms pass
through the forest, throwing down nearly everything before them. Mr. Lapham
gives a map of these windfalls in one district; they are very conspicuous, firstly,
because the trees, having a certain quantity of earth entangled among their roots,
continue to vegetate for several years; and, secondly, because even when the
trees themselves have died and rotted away, the earth so torn up forms little
mounds, which are often mistaken by the inexperienced for Indian graves.
“From the paucity of these little ‘tree-mounds,’ we infer that no very great
antiquity can be assigned to the dense forests of Wisconsin, for during a long
period of time, with no material change of climate, we would expect to find great
numbers of these little monuments of ancient storms scattered everywhere over
the ground.”

But there is other more direct evidence of ancient agriculture. In many places
the ground is covered with small mammillary elevations, which are known as
Indian corn-hills. “They are without order of arrangement, being scattered
over the ground with the greatest irregularity. That these hillocks were formed
in the manner indicated by their name is inferred from the present custom of
the Indians. The corn is planted in the same spot each successive year, and
the soil is gradually brought up to the size of a little hill by the annual addi-
tions.” + But Mr. Lapham has also found traces of an earlier and more systematic
cultivation. ‘These consist “of low, parallel ridges, as if corn had been planted
in drills. They average four feet in width, twenty-five of them having been

counted in the space of a hundred feet; and the depth of the walk between them

¢ Lc, :p. 90, t Lapham, l. c., p. 19.

334 NORTH AMERICAN ARCHAOLOGY.

is about six inches. 'These appearances, which are here denominated ‘ancient
garden-beds,’ indicate an earlier and more perfect system of cultivation than that
whicn now prevails ; for the present Indians do not appear to possess the ideas
of taste and order necessary to enable them to arrange objects in consecutive
rows. ‘Traces of this kind of cultivation, though not very abundant, are found
in several other parts of the State.” (Wisconsin.)

Date.—In the ancient monuments of the Mississippi valley it is stated that
no earthwork has ever been found on the first or lowest terrace of any of the
great rivers, and that “this observation is confirmed by all who have given
attention to the subject.” If true, this would, indeed, have indicated a great
antiquity, but in his subsequent work Mr. Squier informs us that “they occur
indiscriminately upon the first and upon the superior terraces, as also upon the
islands of the lakes and rivers.” Messrs. Squier and Davis* are of opinion that
the decayed state of the skeletons found in the mounds may enable us to form
“some approximate estimate of their remote antiquity,”’ especially when we con-
sider that the earth around them “is wonderfully compact and dry, and that the
conditions for their preservation are exceedingly favorable.” “In the barrows
of the Ancient Britons,” they add, “entire well-preserved skeletons are found,
although possessing an undoubted antiquity of at least eighteen hundred years.”
Dr. Wilsont also attributes much importance to this argument, which, in his
opinion, “furnishes a stronger evidence of their great antiquity than any of the
proofs that have been derived either from the age of a subsequent forest growth,
or the changes wrought on the river terraces where they most abound.” ‘This
argument, if it proves anything, certainly requires a much longer time than
eightee nm hundred years, and carries us back, therefore, far beyond any antiquity
indicated by the forests. ‘These, nevertheless, have also a tale to tell. ‘Thus
Captain Peck {¢ observea near the Ontonagon river, and at a depth of twenty-
five feet, some stone mauls and other implements in contact with a vein of copper.
Above these was the fallen trunk of a large cedar, and “ over all grew a hem-
lock tree, the roots of which spread entirely above the fallen tree” * * *
and indicated, in his estimation, a growth of not less than three centuries, to
which must then be added the age of the cedar, which indicates a still “longer
succession of centuries, subsequent to that protracted period during which the
deserted trench was slowly filled up with accumulations of many winters.’

The late President Harrison, in an address to the Historical Society of Ohio,

made some very philosophical remarks on this subject, which are quoted by Messrs.
Squier and Davis.§ “The process,” he says, “by which nature restores the
forest to its original state, after being once cleared, is extremely slow. The rich
lands of the west are, indeed, soon éBverda again, but the character of the growth
is entirely different, and continues so for a long period. In several places upon
the Ohio, and upon the farm which I occupy, clearings were made in the first
settlement of the country, and subsequently abandoned and suffered to grow up.
Some of these new forests are now sure of fifty years’ growth, but they have
made so little progress towards attaining the appearance of the immediately con-
tiguous forest as to induce any man of reflection to determine that at least ten
times fifty years must elapse before their complete assimilation can be effected.
We find in the ancient works all that variety of trees which give such unrivalled
beauty to our forests in natural proportions. The first growth on the same
kind of land, once cleared and then abandoned to nature, on the contrary, is
nearly homogeneous, often stinted to one or two, at most three kinds of timber.
lf the eround has been cultivated, the yellow locust will thickly spring up; if
not cultivated, the black and white walnut will be the prevailing growth. * *

* * * Of what immense age, then, must be the works so often referred

© ee Cr Ds LOC: Tleres, avOlely, D: G00.
' ; Wilko, c., vol. i, p. 256. § L. ¢., p. 306.

NORTH AMERICAN ARCHAOLOGY, 335

‘to, covered, as they are, by at least the second growth, after the primitive forest
state was regained ?”

We get another indication of antiquity in the “garden-beds,”’ which we have
already described. This system of cultivation has long been replaced by the
simple and irregular “corn-hills;” and yet, according to Mr. Lapham*, the garden-
beds are much more recent than the mounds, across which they extend in the
same manner as over the adjoining grounds. If, therefore, these mounds belong
to the same era as those which are covered with wood, we get thus indications
of three periods : the first, that of the mounds themselves ; the second, that of the
garden-beds ; and the third, that of the forest.

But American agriculture was not imported from abroad. It resulted from,
and in return rendered possible, the gradual development of American semi-
civilization. This is proved by the fact that the grains of the Old World were
entirely absent, and that American agriculture was founded on the maize, an
American plant. Thus, therefore, we appear to have indications of four long
periods :

1. 'That in which, from an original barbarism, the American tribes developed
a knowledge of agriculture and a power of combination.

2. That in which the mounds were erected and other great works undertaken.

3. The age of the “ garden-beds,”” which occupy some at least of the mounds.
Hence it is evident that this cultivation was not until after the mounds had lost
their sacred character in the eyes of the occupants of the soil; for it can hardly
be supposed that works executed with so much care would be thus desecrated
by their builders.

And 4. The period in which man relapsed into barbarism, and the spots which
had been first forest, then (perhaps) sacred monuments, and, thirdly, cultivated
ground, relapsed into forest once more.

But even if we attribute to these changes all the importance which has ever
been claimed for them, they will not require an antiquity of more than three
thousand years. We do not, of course, deny that the period may have been
very much greater or very much less, but, in our opinion at least, it need not be
greater. At the same time there are other observations which, if they shall
eventually prove to be correct, would indicate a very much greater antiquity.

One of these is an account “ given of a mastodon found in Gasconade county,
Missouri, which had apparently been stoned to death by the Indians, and then
partially consumed by fire. The pieces of rock, weighing from two to twenty-
five pounds each, which must have been brought from a distance of four or five
hundred yards, ‘ were,’ says the narrator, ‘evidently thrown with the intention
of hitting some object.’ Intermixed with burned wood and burned bones were
broken spears, axes, knives, &c., of stone.” This statement, which, if true, is
of the highest importance, is given by Mr. Havent without a word of caution,
and is repeated by Dr. Wilson.t Both these gentlemen refer to the American
Journal of Sciences and Art, (first series, vol. xxxvi, p. 199,) as if they were
quoting from an article communicated to that respectable journal. Now, the fact
is that the only authority for the statement is an anonymous correspondent of
the Philadelphia Presbyterian. The editor of the American Journal, while re-
printing the communication, inserted a notice requesting the author to make
himself known, and to give some more particulars. I cannot, however, ascertain
that, in answer to this appeal, any one came forward to take upon himself the
responsibility of so important an observation.

Nor is this all. The original communication to the Philadelphia Presbyterian
never alludes to the mastodon at all, but refers the skeleton to the mammoth;
and the mastodon was first suggested by the editor of the American Journal.
Under these circumstances it certainly seems to us that some better evidence

PlniCe sels tL. ¢., p. 142. Play Vee; ps LIZ.

336 NORTH AMERICAN ARCHAOLOGY.

will be required before we can be expected to believe that any mastodon was
ever stoned to death by North American Indians.

There are, indeed, upon record other facts of a similar tendency. We have,
however, already exceeded our limits, and we will therefore defer the considera-
tion of them to some future opportunity.

If, however, the facts above recorded justify the conclusion that parts at least
of North America once supported a numerous and agricultural population, then
we cannot but ask, What fatal cause has destroyed this earlier civilization ?
Why are these fortifications forsaken—these cities in ruins? How were the
populous nations which once inhabited the rich American valleys reduced to the
poor tribes of savages which the Europeans found there? History suggests by
luxury or war. And the archeologist, if he perceive little evidence of the first,
finds abundant proof of the second.

HISTORICAL SKETCH

OF THE

ACADEMY OF SCIENCES OF PARIS.

Bry M. FLOURENS,

PERPETUAL SECRETARY, ETC. TRANSLATED FOR THE SMITHSONIAN INSTITU-
TION, BY C. A. ALEXANDER.

The Academy of Sciences of Paris was established in 1666, at a time when
Italy had already seen the rise and fall of its Academy of the Lyncei, (founded
at Rome in 1603, by the Prince Cesi, and extinct after his death,) and could
still boast its Academy del Cimento, founded at Florence in 1651. Germany,
too, had its Academy Nature Curiosorum, founded in 1652, and England ite
Royal Society, definitely established in 1660, but existing for some time pre-
vious. In the order of legal date, therefore, our own Academy is but the fifth,
yet had it existed in a free or private form before it received a regular organi-
zation by order of the King. As afew men of letters, meeting in 1629 at the
private residence of Courart, “without noise or pomp,” as Pelisson tells us.
‘cand solely with a view to the pleasures of intellectual association and a rational
life,” laid the foundation of the French Academy, (formally organized by Car-
dinal Richelicu, in 1635,) so the Academy of Sciences commenced in the
assembling of a small company of savants at the houses, first of Monmor, and
afterwards of 'Vhevenot and Bourdelot. Here experiments and new discoveries
were examined, and hither, as these meetings soon became celebrated, learned
foreigners resorted ; here the Italian Boccone presented his observations on the
coral and shells of Sicily, and the Danish Stenon, a man of genius and an
anatomist and geologist of great penetration, read his ingenious discourse on the
anatomy of the brain.

“Tt is perhaps these assemblages of Paris,’’ says Fontenelle, “which have
given rise to many of the academies in the rest of Europe. It is, at any rate,
certain,” he adds, “that the English gentlemen who laid the first foundations of
the Royal Society of London had travelled in France and been received in the
houses of MM. Monmor and Thevenot.”

I cite these words of Fontenelle without attaching to them, as may well be
believed, too much importance. Dating from the middle of the seventeenth
century, a new taste in philosophy had spread itself almost everywhere, and
had as generally given rise to Academies.* As soon as the learned world began
to grow weary of scholastics, that philosophy of words which had so long hin-
dered it from perceiving the philosophy of things, (we owe these designations to
Fontenelle,) as soon as it became tired of studying nature only in the ancients,
and chose to study nature herself, Academies sprung into existence.

Academies are the offspring of the intellectual spirit of modern times. This
modern spirit dates from Bacon, Galileo, Descartes; it is propagated through

“Among those of the above mentioned and the succeeding century the academy of Berlin
dates from the year 1700; those of St. Petersburg, Copenhagen, Edinburgh, Madrid, &e.,
belong to the commencement of the eighteenth century.

225

338 ACADEMY OF SCIENCES OF PARIS.

Leibnitz and Newton; it makes itself popular in Fontenelle, d’Alembert, Vol-
taire. ‘The history I am writing is that of the spirit of the sciences from Bacon
and Descartes to our own times.

Bacon offers us, in his New Atlantis, a perfect image of our academies. In
that work there is an institute of Solomon. It is an academy like those of our
day. We might think that in the latter we saw the Atlantis of Bacon carried
into effect; “the dream of a savant realized,” as Fontenelle says in his Hloge
of Marsigli. In the institute of Solomon the members are distributed into see-
tions, and each section corresponds to a science. ‘Three members occupy
themselves. with mechanics, three with physics, three with natural history, &e. ;
some travel in foreign countries to bring thence machines, instruments, models,
experiments, and observations of every sort; there are some whose sole em-
ployment is to try new experiments, &c. “The end of our foundation,” says
one of the members, “is the knowledge of causes and secret motions of things,
and the enlarging of the bounds of human empire to the effecting of all things
possible.”

Fontenelle paints in his own manner—that is, with expressions of which each
has its point and its import—the new spirit which endowed us with academies.
‘We have abandoned,” he says, ‘a sterile system of physics, which has stood for
centuries always at the same point. The reign of words and of terms is past ;
we seek now for things. Principles are established which we understand.
We follow them, and hence we advance. Authority has ceased to have more
weight than reason. What was received without contradiction, because it had
long been received, is now examined and often rejected; and as the plan has
been adopted of consulting, in reference to natural objects, nature herself rather
than the ancients, nature more readily lends herself to discovery, and often,
when solicited by new expedients of interrogation, accords to us the knowledge
of some one of her secrets.” ‘Thus we see the empire of terms is past; things
are preferred; authority is less consulted than reason; nature more than the
ancients ; in a word, we make experiments.

The ancients did not make experiments, or, at least, they made too few.
They made them in no sustained, consecutive, unintermittent manner. Had
they done so, they would have soon felt the need of academies. As Fontenelle
justly says, “the revival of true philosophy rendered academies so necessary
that they were at once established. That mass of materials which the new
sciences—science become experimental—demand, there are no means either of
collecting or preparing, except through the instrumentality of associations, and
associations protected by the government. Neither the information, nor the
care, nor the lite, nor the faculties of an individual would sufiice for it. There
needs too great a number of experiments, too many of different kinds, too many
repetitions of those of the same kind; it is requisite to vary them in too many
modes, and to pursue them for too great a length of time in the same spirit.”

Wherever we see the genius of experiment developed, we witness the rise of
an academy. ‘The Royal Society of London commences with the experiments
of Boyle; the Academy del Cimento is the work of the disciples of Galileo; the
Academy of Sciences of Paris was at first Cartesian, and the systems of Des-
cartes may bave been adverse to experiment, but his noble method, stronger
than his systems, perpetually leads us back to it. Descartes asked of men but
two things—lcisure and the means of making experiments. “If there were in
the world,” he says, “some one whom we knew with certainty to be capable
of making the grandest and most useful discoveries, and his fellow-men should
exert themselves by every means to aid him in attaining the objects of his
research, I see not how they could do aught else for him but defray the ex-
pense of the experiments which he would have occasion to make, and prevent
his leisure from being interrupted by the intrusions of any one.”—/( Discours de
fa methode.) Elsewhere he observes, “the schools seem to me chiefly to have

ACADEMY OF SCIENCES OF PARIS. 339

erred in this; that they have occupied themselves more in the speculative
search for terms to be employed in treating of things than in the search for the
truth of the things themselves, by means of good experiments ; hence, they are
poor in the latter and rich in the former.”

“Up to this time,” says the Cartesian Fontenelle, “the Academy of Sciences
only considers nature in small portions. No general system, for fear of falling
into the inconvenience of precipitate systems, in which the impatience of the
human mind is too prone to take refuge, and which, once established,
oppose the reception of new truths. 'l’o-day we assure ourselves of a fact;
to-morrow of another which has no relation to it. ‘True, we do not shun the
hazarding of conjectures respecting causes; but these are only conjectures.”

Claude Perrault, a man of genius in more than one line, and perhaps a more
practical savant than Fontenelle, in the preface to the excellent memoirs which,
in company with Duverney, he has given us on the anatomy of animals, speaks
the same language with Fontenelle respecting the rising spirit of the Academy.
“What most entitles the memoirs of the Academy to consideration is the irre-
proachable testimony of their assured and recognized verity. Jor they are not
the work of an individual who may readily allow himself to be biased by his
opinion; who does not easily perceive anything but what confirms the first
thoughts he has entertained, and for which he has all the blindness and the
complacency with which one regards his own views. ‘These inconveniences
cannot be incident to the memoirs in question, for they contain no facts which
have not been verified by a whole company, composed of persons who have
eyes for seeing these kinds of objects otherwise than the greater part of man-
kind see them, just as they have hands for handling them with more dexterity
and success ; who see well what is, and could with difficulty be brought to see
what is not; who study not so much to discover novelties as to examine
thoroughly what is alleged to have been discovered, and to whom even the
assurance of having been deceived carries scarcely less satisfaction than a
curious and important discovery. So much, in their minds, does the love of
certainty prevail over everything else.”’ *

The spirit, then, of the Academy of Sciences of Paris has been always the
spirit of experiment, of direct study, of precise observation, the love of certainty.
' At first Cartesian, it afterwards became Newtonian; but whether with Descartes
or Newton, or since Newton and Descartes, it has been always devoted to ex-
periment. ‘To write its history is to write the history of the experimental
method.

I return to the first establishment of the Academy. I say the frst, for there
have, in fact, been two—that of 1666, and that of 1699.“ 'The Royal Academy
of Sciences,” says Fontenelle, “had, by its labors and its discoveries, so well
answered the intentions of the King, that, many years after its establishment,
his Majesty was pleased to honor it with a new degree of attention, and to
confer upon it a second organization, still more noble, and, so to speak, still
more energetic than the first.”

It is a circumstance worthy of note, though it has been but little remarked, that
the idea was at first entertained of creating in 1666, not a simple academy of

* Histoire de l’ Academic des Sciences, (Memoires pour servir a l’ Histoire naturelle des
animaux, preface, p. VII.) Another testimony to the spirit of the Academy, comprising a
judicious estimate of the spirit ef Descartes, (that spirit which manifested its experimental
tendency in spite of systems, ) is that of Mairan, in his Eloge of Pourfour du Petit. ‘It was
to the Academy that he recurred, not in quest of Cartesianism, but of the spirit of Descartes,
the love of experiments, and all the ardor which that philosopher evinced in availing himself
of their help; the spirit, in a word, of doubt and of discussion which characterizes his im-
mortal method no less thanit does the Academy; or rather it was there that he saw Descartes
preferred by some, Newton by others, and still oftener Descartes associated with Newton,
with Leibnitz, with Aristotle himself, and with all the great minds whose meditations and
labors have enriched the human intellect with new acquisitions.”

340 ACADEMY OF SCIENCES OF PARIS.

sciences, but a grand and comprehensive or universal academy. ‘M. Colbert,”
says Fontenelle, “at first conceived the project of an academy composed of all
who were highly skilled in every department of letters. Historians, gramma-
rians, mathematicians, philosophers, poets, orators, were equally to enter into
this great body, in which all, even the most opposite talents, were to be united
and reconciled. ‘The Bibliotheque du Roi was destined to be their common

lace of meeting. ‘The professors of history were to assemble there on Mondays
and ‘Vhursdays; the votaries of the belles-lettres, Tuesdays and Fridays; the
mathematicians and physicists, Wednesdays and Saturdays. ‘Thus no day of
the week was to remain unemployed; and that there might be something in
common which should connect these different companies, there was to be the
first ‘Uhursday of every month a general assembly of all, in which the secreta-
ries were to report the judgments and decisions of their respective assemblies,
and every one might ask a solution of his dificulties; for on what subject would
not these estates general of literature have been ready to answer? If, however,
the difficulties proved too considerable to be at once resolved, they were to be
committed to writing and answered in the same manner, and all the decisions
were to have been considered as issuing from the entire academy.”

This project was not carried into execution; the plan of distinct academies
was adhered to; doubtless because it was perceived that, even for academies,
the first law of labor is dévision. G. Cuvier calls the modern era of the sciences,
in other words their grand era, the era of the division of labor. Our present
Institute has resolved the problem which Colbert proposed to himself—all the
academies united by a common bond of emulation and fame, and each, as regards
its special labors, independent and free.

To the idea of uniting everything, succeeded that of too thorough a sepa-
ration. It was deliberated whether geometricians and physicists should form
distinct societies, or be combined in one. Fortunately, they were combined in
one. The spirit of geometry is the ever present, though often secret, guide
of all our exact sciences.

The rules of the Academy date from the remodelling in 1699. «Till then,”
says Fontenelle, “the love of the sciences constituted almost alone its whole
law.”” In 1699 positive and written laws were prescribed, all dictated by a
sound discretion.

The whole number of academicians was seventy—ten honoraries, twenty pen-
sionaries, twenty associates, and twenty e/eves. ‘The class of honoraries was
not distributed into sections. That of pensionaries was composed of three
geometers, three astronomers, three mechanicians, three anatomists, three chem-
ists, three botanists, a secretary and a treasurer. Of the twenty associates,
twelve were French; two geometers, two astronomers, two mechanicians, two
anatomists, two chemists, and two botanists. ‘The others were foreigners, and
had no designated sections. It was in this list of the eight earliest foreign as-
sociates of the Academy that might have been seen, nearly at the same time,
the names of Leibnitz, Newton, the two Bernouillis, Ruysch, and the Czar
Peter. Of the edeves, each cultivated the science of the pensionary who had
chosen him, for each of these last selected his own eleve; but, in 1716, the
title of e/eve was suppressed ;* ‘a title,’’ says Fontenelle, “which they have
had the delicacy to abolish, though no one disdained it.” In speaking of tho
anatomist T'auvey, whom he himself had chosen as eleve, Fontenelle grace-
fully says: “I believe that I could make no better present to the company
than of M. Tauvey; and though my nomination was not honorable enough for

* In the place of the twenty eleves. twelve adjoints were created, who had a deliberative
voice in matters of science, as had also the associates. This class of twelve adjoints was com-
posed, like that of the associates, of two geometers and the same number of astronomers,
mechanicians, anatomists, chemists, and botanists.

ACADEMY OF SCIENCES OF PARIS. 341

him, yet his desire of entering the illustrious body was such as to prevent his
being fastidious respecting the manner of his entrance.’ Regular ecclesias-
tics, or those attached to any order of religion, could be neither pensionaries,
associates, nor eleves ; but, fortunately, they might be honoraries, and so the
Academy included Malebranche.

Till the reorganization in 1699, the Academy had occupied for its meetings
a small chamber in the Bibliotheque du Roi; in the year just mentioned the
King assigned it at the Louvre a spacious "and magnificent * apartment, and
it was here that its sessions were held for a century. Of these there were two
a week (Wednesday and Saturday,) and each continued at least two hours,
from three to five o’clock. Further, everything had been provided for the
dignified conduct of these sessions. ‘The Academy,” says the rule, “shall
observe great care that on occasion of a difference of opinion among any of the
academicians, they shall employ no term of contempt or asperity towards one
another, either in their discourse or their writings; and even when combating
the sentiments of the learned, whoever they may be, the Academy shall ex-
hort its members to speak with forbearance.” So far was attention to this
point carried, that savants of different denominations were placed by the side
of one another—a geometer beside an anatomist, a botanist beside an astrono-
mer; ‘for, as they did not speak the same language,’’ says Fontenelle, “ pri-
vate conversations were less to be apprehended.”’

It was particularly desired that the discussions of the Academy should not
resemble the disputes of the schools. ‘These words of Fontenelle have much
meaning: ‘“ Nothing can more contribute to the advancement of the sciences
than emulation among savants, but an emulation confined within certain limits.
It was, therefore, decided to give to the academic conferences a form quite dif-
ferent from the public exercises of philosophy, in which the great point is not
to elucidate truth, but to avoid being reduced to silence. Here it was intended
that all shouid be simple, quiet, without ostentation of ingenuity or knowledge,
that no one should think himself obliged to be in the right, and that ihbre
should always be room for receding without discredit ; above all, that no sys-
tem should bear sway in the Academy to the exclusion of others, and that
every door should at all times be left open to truth.’

I shall add here but one particular, and that because it relates to Louis XIV.
“The year 1681,” says Fontenelle, “was a proud one for the Academy,
through the honor which it received of a visit in person from the King.’ On
this occasion the King, accompanied by the Dauphin, by Monsieur, his only
brother, by the Prince of Condé, and a part of the court, visited the library,
the laboratory, where some experiments were made before him, the hall of the
meetings, where Colbert presented him the printed works of the academicians,
&e. On retiring, his Majesty was pleased to say, “ that it was not necessary
for him to exhort the Academy to labor, since of themselves they evinced quite
a sufficient spirit of application.’”’ Louis XIV had a native instinct for glory;
he relished it in all its forms; he protected the arts; he loved letters, and gave
an unwearied attention to the sciences ; the list in which he caused the cele-
brated writers of his time to be inscribed, with a view to recompense them,
received, likewise, the names of the illustrious savants, not only of France,
but of Europe.

EC
HISTORY OF THE ACADEMY, BY FONTENELLE,

When Fontenelle was nominated, in 1697, perpetual secretary of the Acad-
emy of Sciences, he had been a member of the French Academy for six years,
and four years afterwards he became a member of the Academy of Inscriptions

* Expressions of Fontenelle. Histoire de l’ Academie des Sciences, 1689.

342 ACADEMY OF SCIENCES OF PARIS.

and Belles-Lettres. He had, moreover, published all his principal works,
among which his Plurality of Worlds (1686) had formed his true title to the
place of secretary of the Academy of Sciences, as the History of Oracles (1687)
opened to him the doors of the Academy of Inscriptions. His genius was there-
fore formed ; his ideas had taken shape; he was master of his philosophy, his
style, his distinctive manner ; and this was first clearly seen in the two prefaces
prefixed, the one to his History, of 1666, the other to that of 1699—works in
which the new spirit of the sciences shines with so much lustre, and the finest,
no doubt, that he has written.

« Fontenelle,” says Cuvier, “by the clear and lucid manner in which he
exhibited the labors of the Academy, contributed to diffuse a taste for the
sciences more, perhaps, than any one of his time who cultivated them.’ ‘hat is
true; but it is not enough. Fontenelle did not restrict himself to diffusing a
taste for the sciences. No one more ably seconded Descartes, the destroyer
of the scholastic philosophy ; no one, after the great men who founded it, Des-
cartes, Bacon, Galileo, Leibnitz, Newton, better comprehended the modern
philosophy. He was one of the first who discerned the metaphysics of the
sciences, and the first who made them speak the common language. His influ-
ence has been greater than is generally thought. The same thing has occurred
in his case as in Buffon’s: the writer has thrown into the shade the savant and
the philosopher.

§ 1. Of the scholastic philosophy.

The scholastic philosophy sprang from what would cause it to revive to-
morrow if there were no academies: from the persuasion that all was known,
from adhesion to the words of the master, to the authority of the book ; from
resting in terms without proceeding to things. Fontenelle well defined this as
the philosophy of words, and modern philosophy not less justly as the phclos-
ophy of things.

He says, in speaking of the treatise of Duhamel, entitled Philosophia Vetus
et Nova, &e.: “ This work appeared in 1678, and is as judicious and happy an
assemblage as could well be found of the old and new ideas, of the philosophy
of words and of that of things, of the schools and of the academy.” He every-
where mocks at substantial forms and occult qualities: “ words, he says,” “which
have no other merit but that of having long passed for things.”” In all this, it
is true, he follows Descartes. The latter had said of the ancient philosophy,
“Tt contains only words, and I seek only for things.” Of substantial forms
and occult qualities he pronounced, “ that they were nothing more than chime-
ras, more difficultsto be understood than all that was pretended to be explained
by their means ; that they had been invented only to make it easy to give a
reason for everything, if it may be said, indeed, that a reason is given for
things when we explain what is obscure by something which is still more so.”’

It is the daring genius of Descartes which animates the acute intellect of
Fontenelle; an intellect not only acute, but singularly judicious, and which,
when it is necessary, knows how to check Descartes himself. ‘The errors of
Descartes,” he says, “are such that quite often they impart light to other
philosophers, whether it be that when he is deceived he is not far estray from
the truth and the mistake is easy to rectify, or that he sometimes gives original
views and furnishes ingenious ideas, even when he is most astray.’ He fur-
ther says, and still with characteristic felicity, “It is by following the princi-
ples of Descartes that we place ourselves in a position to abandon his opin-
ions.” And again: “It behooves us always to admire Descartes, and some-
times to follow him.” y

There was one point, however, and an important one, in which he could
never abandon Descartes. I mean his prejudices against a vacuum and against
attraction. ‘Attraction and a vacuum,” he says in his Eloge of Newton,

ACADEMY OF SCIENCES OF PARIS. 343

“banished from physies by Descartes, and apparently banished forever, return
under the leadership of Newton, armed with a new force of which they were
thought incapable, and only perhaps a little disguised.’”’ He confounds, in this
Eloge, the attraction of Newton with the occult qualities of the scholastics—a
demonstrated fact with imaginary forces—and, without doubt, he is deceived ;
but we can atlord to pardon the ingenious writer and profound thinker who
had exerted so much talent in defending and extolling Descartes, if he re-
mained Cartesian somewhat longer than others. We must render justice to
Fontenelle for a half century of struggle against the ancients, and forgive him
for having been himself something of an ancient.

§ 2. Of the modern philosophy.

Fontenelle everywhere opposes the modern philosophy to the scholastic.
He calls it, as we have seen, the philosophy of things ; he further calls it (and
here we have the right word) the experimental philosophy.*

The modern philosophy is, in fact, philosophy sprung from the direct obser-
vation of things—from the study of facts—from experiment. And herein this
most decided partisan of Descartes becomes the most judicious admirer of the
great Galileo. “A rare genius,” he says of him, “and one whose name will
always be seen at the head of some of the most important discoveries on which
modern philosophy is founded.’ Since Galileo, experiment is the guide, and.
as Fontenelle has well said, the sovereign mistress of all our physical sciences.
“ We are at present thoroughly persuaded,” he says, “that physics must not
be treated except by experiments.”—Hist. of the Academy of Sciences, 1724.

He delights te point out at once the accurate attention and the auspicious
sagacity which these experiments require. ‘The art of making experiments,”’
he says, “carried to a certain stage, is by no means common. ‘The least fact
which offers itself to our eyes is complicated with so many other facts which
compose or modify it, that it is impossible, without extreme address, to sepa-
rate all that enters into it, or even, without extreme sagacity, to suspect all
that may enter into it. It is necessary to decompose the fact which is before
us into others which have also their own composition ; and sometimes, if the
route has not been well chosen, we become engaged in labyrinths from which
there is no extrication. ‘To us it appears that primitive and elementary facts
have been hidden by nature with even as much care as causes ; and when we
arrive at a sight of them, it is a spectacle altogether new and wholly unfore-
seen.”—Eloge of Newton.

No one before Fontenelle had so distinctly defined the great art of experi-
ment.t 'That whole art, in effect, has but one end, that of giving us simple
facts—simple facts which, compared together according to their nature, give
us laws; and on this last point—which is the most elevated point of the ex-
perimental method—we may again profitably listen to Fontenelle: “The
time will perhaps come when we shall unite in a regular body these scattered
members, (isolated facts ;) and if they are such as we could wish, they will
come together, in some sort, of themselves. Various separate truths, at least,

* ** What the experimental philosophy is in relation to the scholastic.” * * * (Eloge
of Duhamel.) One utility of this work, (the Opticks of Newton, ) as important, perhaps, ‘as
that which we derive from the great number of new facts of which it is full, is, that it fur-
mishes an excellent model of the art with which the experimental philosophy is to be con-

ucted.

t He made an approach to this lucid definition when he said: ‘‘The laws of the impact of
bodies are very simple, but in almost all the effects which they produce to our eyes they are
so enveloped and so smothered under the multitude of different circumstances that it is difti-
cult to disentangle them, and to see them in their natural simplicity. ‘The secret is, to sep-
arate first the greatest number of circumstances possible, and to consider only the cases into
which there enter the fewest of those circumstances.” —Hist. of the Academy of Sciences, 1706.

344 ACADEMY OF SCIENCES OF PARIS.

if in sufficiently large number, strike the mind in so vivid a manner with their
relations and mutual dependence, that it would, seem, that after having been
detached by a species of violence from one another, they naturally seek to re-
unite themselves again.”’— Preface of 1699.

§ 3. Of the metaphysics of the sciences.

Each science has its metaphysics, or, as we more commonly say nowadays,
its philosophy.

Descartes praises, in his cotemporary Desargues, certain new views on the
metaphysics of geometry. ‘The mode,” he says, “in which he commences his
reasoning is so much the more commendable as it is more general, and seems to
be derived from what I am in the habit of calling the metaphysics of geometry.’’
“'The geometrical spirit,”’ says Fontenelle, “is not so identified with geometry
that it cannot be transferred to other subjects of knowledge.’’* And it was
in this connexion that he gave us his striking allusion to Descartes : ‘Sometimes
a great man gives the tone to his whole age, and he to whom we might most
justly ascribe the glory of having established a new art of reasoning was an
excellent geometer.”’

What he admires in the sciences, and would especially challenge admiration
for, is not somuch discovery as the art of discovering: ‘‘Perhaps,’’ he says,
‘the excellence of the geometric methods which from day to day are invented
or improved, will bring us at last to see the import of geometry—that is to say,
of the art of making discoveries in geometry, which is everything;’’ it is less
the material truth than the abstract truth. “Although lines and numbers,” he
says, “should conduct absolutely to nothing, they would still teach us how to
operate upon truths;”’ it is less the fact than the idea. He seeks everywhere
‘that genius of metaphysics which,’’ as he says, “hides itself, and can only be
perceived by eyes sufticiently penetrating.” t

Above physical science he sees an intellectual science: in physical science
the cases are particular, the experiments bounded; it is intellectual science
which gives them a general force, and, to borrow one of his striking expressions,
a universal spirit.t P

§ 4. Of common language applied to the sciences.

‘‘When the Academy of Sciences,” says Fontenelle, addressing the Academie
francaise, “assumed a new form at the hands of oné of your most illustrious
colleagues,§ he conceived the design of diffusing, as far as was in his power, the
taste of the abstract and elevated sciences which formed his sole occupation.
These employed, for the most part, as in ancient Egypt, only a species of sacred

language understood by none but priests and a few of the initiated. Their new

lawgiver desired that they should speak, as far as possible, the common language,

*Elsewhere he says, ‘‘ geometry, and what is still better worth, the geometric spirit.”—
Eloge of Guglielmini. ‘The art of discovery in mathematics is more valuable than the
greater part of what is discovered.”—Eloge of Liebnitz.

t Discours a UV’ Academie francaise, 1741. He says of Leibnitz: ‘‘Hewas a metaphysician,
and it was next to impossible that he should not be so; he had too universal a spirit. “I mean
universal not only because he essayed everything, but still more because in everything he
seized upon the highest and most general principles, which is the character of metaphysics.”—
Eloge de Leibnitz.

+ He employs this expression in speaking of the necessary union of geometry and physics:
‘It is requisite that the subtle speculations of the one should become embodied, so to say,
by connecting themselves with the experiments of the others; and that experiments naturally
limited to particular cases should assume, by means of speculation, a universal spirit, and be
changed into principles.” — Preface of 1666.

§ The Abbé Bignon, member of the Academie francaise and honorary of the Academy of
Sciences.

ACADEMY OF SCIENCES OF PARIS. 845

and he did me the honor of adopting me as their interpreter in this place.” But
this merit—and itis a great one—of having taughtscience to speak the common
language, is the most generally known of Fontenelle’s merits, and I restrict
myself here to a mere mention of it. be

Fontenelle, as has been seen, was nominated secretary of the Academy of
Sciences in 1697; in 1699 the Academy was remodelled, receiving, among other
ordinances, the following: ‘The secretary shall be exact in collecting in sub-
stance all that shall have been proposed, agitated, examined and resolved in
this company, entering it on his register with a reference to each day of assem-
bling, and he shall also insert therein the treatises which shall have been read :
and at close of December of each year he shall give to the public an
abstract of his registers, or an analytical history of the most remarkable acts
and proceedings of the Academy.”

Fontenelle addressed himself at once to the work, and in 1702 appeared the
first volume of his great history. He excuses himself in the first lines for its
retarded appearance: ‘“ According to the ordinance imposed by the King on the
Academy at the beginning of the year 1699, this history ought to have appeared
at the end of that year. But as the entire Academy was remodelled by that
ordinance, it required some time to communicate to the whole a first movement,
which it will henceforward be easy to maintain.””— Preface of 1699.

This, in effect, was the case. From 1702 each year yielded its volume,
containing, in part, the Memoirs of academicians, and, in part, the flistory of
the Academy, by Fontenelle. The latter is composed of two portions—the
general history of the Academy, of its labors, of its ideas, of the sciences with
which it was occupied ; and the history, the Hloge of individual academicians,

We will first consider the general history. In this Fontenelle combined an
abridgment of everything remarkable which had been said or done in the
Academy during the year, with an analysis of the printed memoirs, the whole
discussed and illustrated, and composed, moreover, in a style of such admirable
clearness as to recall at once the line of Voltaire:

‘The ignorant understood, the learned admired him.”

“The design,’ says Fontenelle, “has been that the history should, on all
subjects, whether common to it and the memoirs, or peculiar to the former, be
adapted to the capacity of those who have but a moderate tincture of mathe-
matics and physics.” He goes on to say, “it has been considered that, with
a view as well to profound savants as to those who are not such, it would be
best to present, under two different forms, the materials which compose this
collection ; that the labors of the Academy would thence become better known,
and the taste of the sciences be more widely diffused.” He adds, in fine, “Care
has been taken to intersperse in the history illustrations suited to facilitate the
reading of the memoirs, and some of these will undoubtedly be more intelligible
to the greater part of readers, if associated with that portion of the history whith
corresponds to them.” Still another phrase is worthy of remark, as showing us
that Fontenelle well understood the kind of service which he rendered to his
colleagues. He observes, in his E/oge of the geometer Parent, who was reproached
for the obscurity of his writings: “I cannot help recording it to his honor, that,
in a letter written to his warmest friend two days before his death, he thanks
me for having, as he said, made him intelligible. This was frankly conceding
the fault which was imputed to him, and carrying very far his gratitude for a
slight service which I owed him.”

In reference to the savants whose history he has written, Fontenelle has two
merits: that of having cleared up what is obscure, of having generalized what
is technical in the writings of each; and that of having always employed what each
has bequeathed us that is most important and most durable as the vehicle of
his eulogy. He praises by means of facts which define the character. The

346 ACADEMY OF SCIENCES OF PARIS.

following portraiture of the savants who illustrated by their genius the first
half of the seventeenth century is an instance: “In Italy, Galileo, mathema-
tician to the grand duke, at the commencement of that century first observed
the spots on the sun. He discovered the satellites of Jupiter, the phases of
Venus, the small stars which compose the milky way, and, what is still more
considerable, the instrument of which he availed himself to discover them.
‘Vorricelli, his disciple and successor, devised the famous experiment of the
vacuum, which has led the way to an infinitude of entirely new phenomena.
Cavallerius detected the ingenious and subtle geometry of indivisibles which is
now extended so far, and which, at every moment, embraces the infinite. In
France, Descartes opened to geometers new paths which had not been before
known, and disclosed to phy sicists a multitude of views which either suffice of
themselves or prepare the way for others. In England, Baron Napier distin-
guished himself by the invention of logarithms ; and Harvey by the discovery,
or, at least, the incontestable proof of the circulation of the blood. The honor
which accrued to the whole English nation from this new system of Harvey
seems to have turned the attention of the English to anatomy. Several of
them adopted particular parts of the body as the subject of their researches—
Wharton, the glands; Glisson, the liver; Willis, the brain and the nerves;
Lower, the heart and its movements. About the same time, the reservoir of
the chyle and the thoracic duct were discovered by Pecquet, a I’renchman,
and the lymphatic vessels by Thomas Bartholin, a Dane, to say nothing of the
salivary ducts which Stenon, another Dane, taught us to know still more
exactly than Wharton had done, nor of all which Marcel Malpighi, an Italian
and first physician to Pope Innocent XII, observed in the epiploon, in the
heart and in the brain, anatomical discoveries which, however important, will
yet yield him less honor than his happy conception of extending anatomy even
to plants. In fine, all the sciences and all the arts whose progress had been
arrested for spies acquired, in this, new forces, and commenced, so to speak,
a new career. Preface of 1666.

Tontenelle por. s himself in his Hloge of Duhamel, that first secretary of
the Academy of Sciences whom he has caused us to for eet: “There was required
for this association a secretary who understood and could competently speak
all the different languages of these savants; who might be their common inter-
preter with the public; who could not only throw light on so many intricate
and abstract topics, but give them a certain turn and even grace which authors
sometimes neglect, and which yet the greater part of readers desire; one, in
fine, who, by ‘his char: icter, should be exempt from partiality, and qualified to
render a disinterested account of the academic contests. The choice of M.

Colbert for this functionary fell upon M. Duhamel.” It is in this same Eloge
that we meet with this ingenious remark: “That which ought not to be embel-
lished beyond a certain determinate point is precisely what it costs most pains
to embellish;”’ and nothing could better characterize the writer’s own felicitous
manner and diserimin: ating art.

I have already cited more than once the two prefaces which precede the
histories of the years 1666 and 1699. 'The latter, on its first appearance,
excited attention, not only in France, but in Europe. Not since the discourse
of Descartes on method had there been heard such language applied to such
objects. The admiration was universal. The preface of 1666 had a different
fate. In the first place, it did not appear until several years later; and then, when
it did appear, it attracted scarcely any notice. 'Trublet tells us that in his time it
was almost unknown. ‘Many persons,” he says, “have the history of the
Academy of Sciences since 1699, and buy the new volumes as they issue from
the press. Very few have had the curiosity to go back to 1666, or even know
that M. de Fontenelle had labored on the first memoirs and composed the his-
tory of the first years of the Academy.” Garat, in his Eloge of Fontenelle,

ACADEMY OF SCIENCES OF PARIS. 347

crowned by the Academie francaise, says of the preface of 1699: ‘ This preface,
which comprises but a few pages, has yet made good its claim to be ranked
among the distinguished works of the century. It is the most vigorous and
comprehensive survey of human knowledge from Bacon to the preface of the
Encyclopedia.” This is well and justly said; but of the preface of 1666 there
is not a word. Wherefore this silence? Had Garat not seen it? This I can-
not believe; and yet the preface in question is quite as fine as that of 1699.
Perhaps it is even more so, for there prevails in it a graver strain of eloquence,
and, for that reason, a more excellent one.

Fontenelle, not having been nominated as secretary until 1697, might very
well have acquiesced in the terms of the ordinance, which only exacted of him
the history of the Academy after the year 1699; but the monument which he
raised to the sciences would have thus been incomplete, and he undertook the
entire history from 1666 to 1699. Duhamel had already written in Latin the
history of these thirty-two first years, (Regia Scientiarum Academia Historia,
1698.) Fontenelle, through a considerate delicacy, did not publish the French
history of these years until after the death of Duhamel, and long after. The
latter died in 1706; the history appeared in 1733.

Duhamel had relinquished the functions of secretary in 1697. The lustre of
the sciences, every day augmenting, demanded for them a more brilliant inter-
preter, and Fontenelle succeeded him. Duhamel, a most learned, laborious, and
unpretending man, recalls, by his tone and by his Latin, the ancient period of
the sciences. I ontenelle, by his original genius, his vivacity of thought, his
language, and above all by his French style, represents their new period. To
see the two eras, so different, yet so little distant, we need but compare the
Latin history and I’rench history of the Academy of Sciences, Duhamel and
Fontenelle.

We must still recur to Fontenelle to learn how to speak of others and of
himself. “At the commencement of 1697,” he says, “M. Duhamel resigned
the pen, having represented to M. de Pontchartrain, chancellor of France, that
he had become so infirm as to stand in need of a successor. It would be to my
own interest to conceal here the name of him who had the temerity to take the
place of such a man; but the gratitude which I owe him for the goodness with
which he accepted me, and for the care which he took to form me, does not
permit me to do so.”—Lloge de Duhamel.

In 1737 Fontenelle, at the age of eighty years, and having been secretary for
forty, felt, in his turn, the necessity of retiring. He wrote, therefore, to Car-
dinal de Fleury, asking anew the superannuation (veterance) which he had
already applied for seven years before. “It is just seven years,” he said,
“since I obtained from your eminence permission to abdicate the only dignity
which I hold in this world, that of secretary of the Academy of Sciences. I
then yielded to the instances of several of the members and remained, though
compliment, no doubt, had its part in their remonstrances. Seven more years
greatly strengthen the reasons which I then had. It is very far from being
the case that every one is exempt from the danger of self-delusion. Whatever
difference there may be between France and the Academy, I renew my earnest
prayer, and am, with very profound respect, &c.” ‘The cardinal, who had his
own reasons for not admitting that one is old at eighty years, (he was himself
seventy-seven,) returned but an evasive reply. Fontenelle was therefore
obliged to write to him a third time, three years after, in 1740; and this time
the cardinal yielded, not, however, without reservations. ‘You are,” he re-
plied to him, “only an idle fellow and a libertine; but still it is necessary to
have some indulgence for characters of that sort.’

Fontenelle was nominated at the beginning of 1697; and, as he retired at
the close of 1740, was, consequently, secretary for nearly forty-four years.

348 ACADEMY OF SCIENCES OF PARIS.

Ti,
ELOGES OF THE ACADEMICIANS BY FONTENELLE.

The Lloges of Fontenelle commence in 1699,* with the reorganization of
the Academy, and he had already produced twelve in the year 1708. At that
time a small volume appeared, entitled, “ History of the Reorganization of the
Academy of Seiences in 1699, and Historical Eulogies of the Academicians
who have died since that time, with a preliminary discourse on the utility of
Mathematics and of Physies.’

In this work, forming ‘the first collection of Fontenelle’s Eloges, are embraced
twelve memoirs, being those of Bourdelin, Tauvey, 'T uillier, Viviani, the
Marquis de L’ Hopital, Jacques Bernouilli, Amontons, ‘Duhamel, Regis, Marshal
Vauban, the Abbé Gallois, and Dodart. The preliminary discourse is the
admirable preface of 1699, of which I have repeatedly spoken. The history
is a curious though brief recital of the facts attending the recent inauguration
of the Academy. An advertisement, which precedes the whole, announces that
“the coXection would be followed by no other until there was a sufticient num-
ber of Elvoges to form a second v olume equal to the first.” This condition was
fulfilled in 1717, when another volume appeared, followed by a third in 1722,
and subsequently by another series of the H/oges. Of these memoirs, Fontenelle
produced sixty-nine, and pronounced them all before the Academy within the
space of forty-two years: 1699—1740.

The sceond volume is introduced by this simple and interesting preface:
“There appeared, some years ago, a volume composed of the History of the
Reorganiz: ition of the Academy of Sciences and Eloges of Academicians since
dead. ‘The present volume contains only the subsequent Eloges. ‘They have
all been composed to be read in the meetings of the Academy, and some expres-
sions will be found in them which ‘have a relation to that circumstance. The
title of H/oges can hardly be considered just; that of Lives would have been
more so; for properly they are but /¢ves, such as would have been written with
the desien simply to render justice. I guarantee their truth to the publie. A
very large number of the facts which I relate have fallen under my own obser-
vation; ‘others L have derived from the writings of those of w hom I speak ;
others from the writings even of those who have assailed them, or from memoirs
furnished by persons whose information was most exact. I have not felt at
liberty, still less have I purposed, to draw portraits at pleasure of those whose
memory is so fresh. If, in the mean time, it should be thought that they have
not been sutliciently praised, I shall neither be surprised nor annoyed.”

I confess myself well pleased to see that Fontenelle was not satisfied with
the title of Evoges. ‘The word /fe is the true and natural word; that of Eloge
is but the conventional expression of a given literary epoch. Elsewhere he
remarks: “These /oges are simply historical—that is to say, true.’’ And true
they are to their full extent; hence it is that each is stamped with its own
character, its own tone, with an originality springing from that of the person-
age who is the subject, and hence the E loge of Meéry, or of Couplet, is so differ-
ent from that of Newton or of Malebranche.

The Lloges of Fontenelle for the first time, in France, brought savants into
public notice, and the sciences into fashion. If he ably seconded Descartes, the
founder of a new philosophy, he not less ably seconded Colbert, as much an
innovator in pobtics as Descartes in pevosopey. But who remembers now

aes As the history of the Academy should be, as vouch as possible, that of the academi-
cians, we shall not fail, when one of them dies, to render him a species of funeral honors in
& separate article, in which we shall collect the most considerable particulars of his life. M.
Bourdelin, having died in the year whose history we now write, will be the first towards
whom the Academy will acquit itself of this duty.”"—Histoire, &c., 1699.

ACADEMY OF SCIENCES OF PARIS. 349

what Colbert performed for savants and for science? What Richelieu had been
for the Academie francaise, that was Colbert for the Academy of Sciences.
We have noticed his grand idea of a general and universal academy, an insti-
tute such as we now possess. I find in every page of the H/oges of Fontenelle,
traces of that assiduous, active, comprehensive molbericile W eh Colbert mani-
fested for the sciences; a solicitude which, in a statesman, was then so great a
novelty.

“M. Colbert,” says Fontenelle, “favored letters, induced thereto, not only by
his natural inclination, but a wise policy. He knew that the sciences and arts
even alone suffice to render a reign glorious; that they extend the language of
a nation more, perhaps, than conquests; that they confer the empire of intellect
and of industry equally flattering and useful; that they attract a multitude of
strangers, who enrich the country by their curiosity, adopt its habits, and attach
themselves to its interests. J*or many centuries, the University of Paris has
not contributed in a less degree to the grandeur of the capital than the residence
of its kings. To M. Colbert we owe the lustre’ to which letters have attained,
the rise of this Academy, of that of inscriptions, of the Academies of painting,
sculpture and architecture, the new favors obtained from the king by the French
Academy, the impression of a great number of excellent books at the expense
of the royal press, a vast augmentation of the Bibliotheque du Roi, or rather
of the public treasury of the learned, an infinitude of such works as great
authors and skilful artisans only accord to the caresses of ministers and princes,
a taste for the beautiful and refined everywhere diffused and continually gath-
ering strength.’”’—EHloge of the Abbe Gallovs.

Here we have Colbert painted, after the manner of Fontenelle, by facts. The
following are some of these facts, chosen among many others, for Fontenelle
forgets none of them. His particular eulogies of different savants seem the
general and continued eulogy of this great minister.

“Tf any new book of reputation or discovery of moment came to light, Col-
bert was soon apprized of it, and the recompense was not long deferred. ‘The
liberalities of the king were extended even to foreign merit, and sometimes
sought out in the very depths of the north a savant surprised to find that he
was known.”

Homberg visited Paris when he was young, and, as sometimes happens with
young men who visit Paris, for some time evaded the injunctions of his father
to return. ‘At last,’ says Fontenelle, “the father grew impatient and his
commands more pressing. Homberg prepared to obey, and was about entering
the carriage, when M. Colbert sent to require his presence on the part of the
king. T his minister, believing that persons of eminent merit are a benefit to
the state, made such advantageous offers to induce him to stay, that Homberg
asked for some little time to form a decision, and finally determined to remain.”

About 1682, a young geometer, then quite unknown, had resolved in a feli-
citous manner a problem which had been recently propounded. “ Forthwith,”’
says Fontenelle, ‘“ M. Colbert, who had spies to discover hidden or rising merit,
disinterred M. Rolle in the extreme obscurity in which he lived, and bestowed
on him a gratuity which became afterwards a settled pension.’

Charles II, king of England, had sent to Louis XLV two repeating watches,
the first which had been seen in France. These watches, which could only be
opened by a secret artifice, got out of order, and it was necessary to repair
them. But, how to open them? After some vain efforts, the horologist of the
king (‘with a courage,” says Fontenelle, “not unworthy of reme sa uanees
told M. Colbert that he knew a young Carmelite who was capable of effecting
it. The watches were, therefore, given to this young Carmelite, who promptly
opened them, and, moreover, repaired them, without knowing that they were
the king’s. ‘Some time after,’ says Fontenelle, “an order arrives from the
minister, directing M. Scbastien to come to him at seven o’clock in the morn-

350) ACADEMY OF SCIENCES OF PARIS.

ing of a certain day; no explanation of the reason of this order; a silence
which might well cause some alarm. Father Sébastien fails not to arrive at
the hour; presents himself, confused and apprehensive; the minister praises
him on account of the watches, tells him for whom he had worked, exhorts
him to cultivate his great talent for mechanics, and in order still more to
encourage him, and speaking still more to the point in his capacity of minister,
confers on him a pension of six hundred livres; the first year being paid,
according to the custom of those times, in advance.’ ‘ Father Sébastien,”
adds I°ontenelle, “was then but nineteen years of age; and with what a desire
of meriting approval must he have been inspired! Princes and ministers who
do not obtain suitable agents for every purpose, either do not know that there
is need of men, or have not the art of finding them.”

I have said that Fontenelle forgets nothing which was done by Colbert.
“Tt was in 1665,” he tells us, “that for the first time appeared the Journal des
Savans, the idea of which was so novel and happy, and which still subsists
with greater vigor than ever, accompanied by a numerous progeny, dissemi-
nated throughout Europe, under the different names of Nouvelles de la repub-
lique des lettres ; Histoire des ouvrages des savants ; Bibliotheque universelle ;
Bibliotheque chowsie ; Acta eruditorum ; Transactions philosophiques ; Memoires
pour histoire des sciences et des beaux-arts, &e. M. de Sallo, ecclesiastic
councillor to the Parliament, had conceived the design of it, and had associated
with himself the Abbé Gallois, who, from the vast variety of his erudition,
seemed born for this labor, and, what is more, and by no means common with
those who know everything, who knew French, and wrote it well.”

I find, from Fontenelle, that the Journal took at first a tone somewhat too
bold ; that it censured too freely most of the works which appeared ; that the
republic of letters, thinking its liberty menaced, revolted, and the publication
was suspended at the end of three months. It reappeared in 1666, under the
sole direction of the Abbé Gallois, “and immediately,” says Fontenelle, «M.
Colbert, struck with the beauty and utility of the Journa/, took a taste for the
work.” Irom that moment the fortunes of the Journal were secured ; a happy
event, not only for letters and science in general, but for the Academy in
particular.” “The Abbé Gallois,” says Fontenelle, “enriched his Journal
with the principal discoveries of the Academy, which were then made known
to the public only through this medium.”

“In 1683, M. Colbert was lost to letters.” Fontenelle says but these few
words ; es what do not these few words convey after all that precedes !

By the side of Colbert, who renovated by means of the sciences the face of
the most civilized empire of the world, I place the memorial of the Czar Peter,
who carried them into countries the most barbarous.

The czar came to Paris in 1717; he came with the curiosity of genius; he
visited everything and penetrated everywhere, and especially did he observe
the Academy of Sciences. ‘No sooner,’ says Fontenelle, “had he returned
into his own dominions, than he wrote to the Abbé Bignon, through M.
Erskine, a Scotchman, who was his first physician, that he desired to become
amember of this company; and when acknowledgments were made him with
al] the respect and gratitude that were his due, he wrote with his own hand a
letter to the Academy, which we will not venture to call a letter of thanks,
though coming from a sovereign who had long been accustomed to regard
tanec le asaman.” “It was fhewectonul obligatory,” continues Fontenelle,
“to send him, each year, the volume due to him in his quality of academician,
which was always graciously acknowledged as an attention on the part of his
colleagues.” —Hloge of the Czar Pierre ah

In the letter, which Fontenelle does not venture to call one of thanks, the
Czar said to the Academy: “The choice which you have made of us personally
to be a member of your illustrious society could not but be highly agreeable

ACADEMY OF SCIENCES OF PARIS. 351

to us. Hence we have not been disposed to defer our acknowledgment of the
joy and gratitude with which we accept the place you offer us therein, having
nothing at heart more than to make every effort in our power to promote, in
our estates, the advancement of the sciences and fine arts, so as thereby to
render ourselves more worthy of being a member of your society.” And
he adds: ‘As there had never yet been any very exact chart of the Caspian
sea, we despatched competent persons thither to construct one, with all possible
care, upon the spot, and we send it to the Academy in the confidence that it
will be kindly received as a memorial of ourself.”’

There is an art common to all the Eloges of Fontenelle, and a special art in
the portrait which he traces of each academician. ‘Thus he graphically pre-
sents to us the physician and botanist, Morin: “ Retiring to rest at seven
o'clock and rising at six, throughout the year, he then gave three hours to his
devotions. He now repaired to the post of his duties, the Hotel Dieu, going
thither at five or six o’clock in summer, and between six and seven in winter.
Mass he generally heard at Notre Dame. After his return home he read the
Holy Scriptures, dined at eleven, and, when the weather was fair, spent till
two in the royal garden, where he gratified his earlicst and strongest passion
by the examination of new plants. After this, if there were no poor whom he
was called upon to visit, he shut himself up and spent the rest of the day in
reading books of physic or erudition, chiefly the former, as his profession
required. ['This likewise was the time at which he received visits, if any were
paid him. He often used this expression: ‘Those that come to see me do
me honor; those that stay away do me a favor.’ It is easy to conceive that a
man of his temper was not crowded with salutations; there was only now and
then an Antony that would pay Paul a visit.’’| *

He thus paints to us the great astronomer Cassini, ‘“‘ Whose spirit was even,
tranquil, exempt from those vain disquietudes and senseless agitations which
are the most afflicting and the most incurable of all maladies. A vast fund of
religion, and, what is still more, the practice of religion greatly promoted this
perpetual calm. The heavens, which declare the glory of their Creator, had
never more discoursed of it, nor ever carried more conviction to any one than
to him.”’

He paints to us La Hire: “ All his days, from beginning to end, were occu-
pied by study, and his nights often interrupted by astronomical observations.
No diversion for him but that of a change of labor; no other bodily exercise
but going from the observatory to the Academy of Sciences, to that of archi-
tecture, to the royal college, of which also he was a professor. Few
persons can comprehend the happiness of a recluse, who is such by a choice
which is every day renewed.”

After indulging himself in the praise of his savants, FPoutenelle seems to
feel new pleasure in transferring his praises to the sciences themselves. He
says, in the memoir of Lemery: “ We are almost weary of noticing this merit
in those of whom we have to speak. It is a praise which very generally
appertains to that particular and not numerous class of persons whom converse
with the sciences separates from that with men.’ In reference to Varignon
he says: “His character was as simple as his superiority of intellect would
imply it to be. I have already given this same praise to so many members of
this Academy, that it might be thought the merit of it belongs rather to our
sciences than to our savants.”

Portraying others, he portrays himself. He well says of the Theodicea of
Leibnitz: “This work of itself would sufficiently represent its author;’”’ and as

* The words between brackets are an addition to the rather meagre extract of the text, and
are taken from a translation of Fontenelle’s Eloge of Morin, by Dr. Johnson, first printed
ia the Gentleman’s Magazine for 1741.—TR.

352 ACADEMY OF SCIENCES OF PARIS.

much might be said of his own Eloges in regard to himself. We there see the
character of his intellect: “‘ Luminous, comprehensive, and capable of adding
something of its own to all acquired knowledge.”—Eloge of Saurin. Wesee
also his disposition and turn of thought. He says of Reyneau: ‘“ He held
himself aloof from business, still more from intrigue, and prized highly the
advantages, so little appreciated, of being nothing ;”’ of Tschirnaus: ‘“'True
philosophy had penetrated to his very heart, and established there that
exquisite tranquillity which is the greatest and the least coveted of all posses-
sions ;” of Varignon: “I have never seen any one who had more conscientious-
ness—I mean to say, who applied himself more scrupulously to satisfy the
inward sentiment of duty, and contented himself less with having satisfied
appearances ;”’ and in the Kloge of Homberg: ‘“‘ Whoever has leisure for
thought sees nothing better that he can do than to be virtuous.”

The mind of Fontenelle had all the boldness which a superior judgment
permits, or rather supposes. Otherwise, would he have chosen Descartes for
amaster? ‘In all inquiries,” says he, ‘the first systems are too limited, too
narrow, too timid, and it would seem that truth itself can only be the reward
of a certain audacity of reason.’ But he stipulates that this audacity should
be sagacious and discreet. ‘It is necessary,’’ he says, ‘“ to dare in all things,
but the difficulty is to dare discreetly; it is to reconcile a contradiction.”—
Eloge of Chazelles.

No one had more clearly or closely observed the powers of the human intel-
lect than the continuer of Descartes and the historian of Leibnitz and of New-
ton; but he had observed those powers without being dazzled, and was aware
of their limits. “A first veil,” he says, “which covered the Isis of the
Egyptians, has been for some time removed; a second, if you please, has been
so in our own day; a third will not be removed, if that third be the last.’”—
Eloge of Ruysch.

Colbert, having founded the Academy of Sciences in 1666, continued to be
its immediate protector while he lived. On his death, which occurred in 1683,
the Academy was transferred to Louvois, appointed superintendent of construe-
tions, arts and manufactures in the place of Colbert; and on the death of Lou-
vois in 1691, it passed to Pontchartrain, at first Secretary of State, and after-
wards Chancellor of France. Pontchartrain gave the Academy in charge to
the Abbé Bignon, his nephew, and “by doing so,” says Iontenelle, “rendered
to the sciences one of the greatest favors they have ever received from a minis-
ter.’ ‘The abbé, who had long presided over the body, and thoroughly under-
stood its constitution, contributed much, in fact, by his views and his influence,
to the great reorganization of 1699. When the Duke of Orleans became Re-
gent, he reserved to himself the government of the Academy. “He treated
our sciences,’’ says Fontenelle, “as a private domain, of which he was jealous.”
This prince, it is well known, possessed much taste and even talent for the
sciences; he had become a chemist with Homberg, and evinced that specula-
tive curiosity which belongs to genius, but unfortunately as ill regulated as all
his other qualities.*

The Regent having assumed the direction of the Academy, the personage who
represented it, whether secretary or president, Fontenelle or the Abbé Bignon,
was naturally called upon to assist him in his labors. Fontenelle, with his
usual delicacy, wished to defer this honor to the Abbé Bignon. “ Nothing
could be more courteous,” replied the latter, “ than your proposal that I should
have the honor of rendering to his Highness, the Regent, an account of the
affairs of the Academy of Sciences ; but the matter would be infinitely better

*<‘FTe was curious in all sorts of arts and sciences. He has often told me that he had
sought, by all the means at his command, to obtain a sight of the devil and other extxaor
dinary objects, and to know the future.”— Memoires de Saint Simon, V, p. 121.

ACADEMY OF SCIENCES OF PARIS. aap

in your hands. The most important point is, that the Regent has declared
that he reserved our sciences to himself alone. You and I will not quarrel
about the reports he may require. But, however honorable this distinction
may be to our Academy, or flattering to ourselves, I still have a fear that it
may expose our poor savants to envy and the ill offices which might follow.
I fear, moreover, that in the multiplicity of more important affairs with which
his royal Highness is overwhelmed, it will not be possible for him to enter into
all our details, whose numbers frighten even yourself, and which will hereafter
undoubtedly increase. ‘The example of our dear Academie francaise alarms
me. From the day that the King condescended to take the title of its Pro-
tector, and it had the honor, consequently, of being immediately responsible to
none but his Majesty, you know to what extent the spirit of state affairs in-
vaded it, and how many evils, or at least inutilities, followed in their train.
The Academy would soon be reduced to nothing, if it fell into a condition
anything like this. Think of these things, I pray you.”

These particulars are curious ; happily, however, the Abbé was needlessly
alarmed. ‘The constitution of the Academy was an excellent one, and there
are two things therein which strike me as possessing singular wisdom: one,
that it had entire liberty in the domain of the sciences; the other, that it was
absolutely limited to that domain: no function, either of administration, or
even of instruction.

The Academy is no university. The barrier which separates them should
be eternal. Universities teach, the Academy discovers and improves ; this the
very terms of its device inculcate: Invenit et perficit. Nor has it any more
an administrative function. The Academy seeks, as it ought to seek, in every-
thing, ideal excellence ; administration aims only at practicable excellence.
Solon gave to the Athenians, not the best possible laws, but such only as they
could bear.

The numerous editions of the E/oges which have appeared since the death of
their author are more or less infected with verbal errors. In one we read :
“Two or three great geniuses suffice to advance theories very far in a short
time, but practice demands greater slowness, because it depends on too many
hands, most of which are plus habiles.”’ Read peu habiles, 7. e. little qualified.
Again: “ Father Malebranche had taken little pains to cultivate the faculty
of imagination ; on the contrary, he was very prone to decry it ; but he had that
faculty in a very high and vivid degree, though it labored for an ingrate in
spite of himself, and directed (ordonnait) reason while it hid itself from her.’’
Kead embellished (ornait) reason. In an edition of Fontenelle printed at the
close of the last century, the word Monsieur, or its substitute the capital M..
has been suppressed before the name of every personage; so that Fontenelle,
the most scrupulous observer of all proprieties, is made to call M. de Pontchar-
train simply Pontchartrain, or the Chancellor ; the Minister M. de Maurepas,
Maurepas, &c., &e. He had said: M. Tournefort, M. Leibnitz, M. Newton,
&e.; the editor makes him say: Tournefort, Leibnitz, Newton, Bossuet, Col-
hert, Louvois, &c. In the Eloge of Sauveur we find: *“ One thing determined
Sauveur to follow the sage counsel of Condom ;’’ Condom being the great
Bossuct, then dead but afew years. This sort of anachronism changes the
whole physiognomy of the book.

Bosnage thus portrays Fontenelle: “Some pretend that mathematics dis-
tort and impoverish the mind; M.de Fontenelle might with reason serve to
retute this disparaging idea in regard to mathematicians ; he carries not into
the world that absent and dreamy air imputed to geometers ; he speaks not as
a savant who knows nothing beyond the terms of his art. The system of the
world, which had been, for any one else, the groundwork of a dogmatical dis-
sertation, not to be understood without the help of a dictionary, becomes, in
his hands, an agreeable pleasantry, and the reader who dreamed only of being

238

354 ACADEMY OF SCIENCES OF PARIS.

amused, finds himself in some sort an astronomer without having thought of
being so.”

Voltaire writes to Fontenelle: «You know how to render things attractive
which many other philosophers scarcely render intelligible ; and nature owed
to France and to Europe a man like you to correct the savants, and give the
ignorant a taste for the sciences.”* | No one more than Fontenelle possessed
that “ subtle and dexterous art’ which he admired in Leibnitz, “the art not
only of arriving at truth, but of arriving at it by the shortest paths ;” of occu-
pying always those elevated points of view which command wide horizons, and
of separating or disentangling ideas, which was constantly with him an object
ot the greatest solicitude.

''The life of Fontenelle is so generally known that we shall recall but few
particulars of it. Born at Rouen, he there composed most of his earlier works.
and afterwards established himself in Paris. He was a nephew of the great
Corneille, who gave the Cid to France the year before that in which Descartes
presented to it the Discourse upon Method. Much has been written about Fon-
tenelle, and the tone adopted has not seldom been sufficiently censorious.
Grimm, for instance, strongly reproaches him for his famous expression, “If
[ had my hand full of truths, I would take good care how I opened it.” But
Grimm need not have been troubled ; Fontenelle, in spite of the phrase, opened
iis hand often enough. Voltaire sarcastically calls him the discreet Fontenelle.
Was it necessary that he should be as indiscreet as Voltaire? ‘The following
sayings of his seem better to paint his character: “I have never permitted
inyself to cast the slightest ridicule upon the least of the virtues ;’”’ and his
reply to the Regent, who pressed him to accept the perpetual Presidency of
the Academy, “ Ah, Sire, do not deprive me of the pleasure of living with my
‘quals.”’

Fontenelle was born the 11th of February, 1657, and died 9th January.
i757, having thus lived almost exactly a century. His birth and death con-
neet two remarkable epochs, the death of Descartes and the meridian fame ot
Voltaire.

APPENDIX TO THE FOREGOING SKETCH.

‘«« ontenelle,” says Arago, “had so brilliantly fulfilled the functions of sce-
retary of the Academy of Sciences, that at his death no one was willing to
succeed him. After much solicitation, Mairan consented to exercise those
functions, provisionally, in order to give the learned body time to make a
choice which it should not afterwards have occasion to regret. It was felt at
last that the only means of avoiding all injurious comparison would be to give
to the nephew of Corneille a successor content not to imitate him, and who
should disarm criticism by the modesty of his pretensions. Under these cir-
cumstances Grand-Jean de Fouchy became, in 1743, the official organ of the
old Academy.

“Fouchy had ceeupied this place more than thirty years,when Condorcet en-
ered the leaned company. ‘The age and infirmities of the perpetual secretary
made him desire an assistant, and he cast his eyes on this the youngest of his
colleagues. As this measure seemed equivalent to the creation of a survivorship.
i: proved distasteful to that portion of the Academy which usually allied itself
with the views of Buffon, while another portion, acting under the leadership
af d’Alembert, with equal ardor supported the nomination.” ‘The oppo-
sing candidate was Bailly, the astronomer, certainly a noble and worthy com-

* Voltaire terms Fontenclle: ‘‘The first of men in the new art of diffusing light and
evace over the abstract sciences ;”’ and he adds: ‘‘ That he stands first among all the savants
who have not been gifted with the faculty.of invention.” (Svecle de Louis XIV.) Fonte-
nelle, it is true, made no discovery in the sciences, but he discovered the style for ciffusing
them. That new ert of which Voltaire speaks is his invention.

ACADEMY OF SCIENCES OF PARIS. 355

petitor; but the acrimony excited on this occasion was such as it is to be
hoped may seldom be allowed-to enter the halls consecrated to science and hu-
man improvement.

Edita doctzina sapientum, templa serena.

For some weeks, says Arago, the Academy presented the aspect of two
hostile camps, and the asperity of the contest mi oe be conceived when we learn
that to the illustrious name of d’Alembert was applicd the stigma of having
proved “equally faithless to friendship, to hehoe and the fret principles of
honesty.” ‘The charge rested on the fact that d’Alembert, looking to an early
vacancy of the office, had first held out encouragements to Bailly to qualify
himself for its discharge, and six years afterwards had offered similar induce-
ments to Condorcet. ‘The only injury to the two young aspirants would seem
to have been to engage them to devote a portion of their time to the composition
and publication of probationary Eloges, which brought their respective merits
before the public eye and crowned them with the applause of the most judi-
cious critics. “It is seldom,” continues Arago, “that abstract principles im-
passion men to sucha degree as on this occasion, while to the outward world
the question clearly put seemed only to be, shall the successor of Fontenelle
be called Bailly or Condorcet?’’ 'The choice of the Academy fell upon Con-
doreet.

It is to the period here reviewed, we must presume, that the words of the compi-
ler of the article “ Royal Academy of Sciences” in the Encyclopedia Britannica
were designed to apply : ‘Through the intrigues or intervention of the court
for the admission of unworthy members or the exclusion of the meritorious, the
Academy had gradually sunk in public estimation until admission not only
ceased to be an honor, but even became a subject of contempt and derision.
Hence the following humorous and well-known epitaph :

‘Ci-git Piron, qui ne fut rien,
Pas méme academien.’”

Here there is a manifest confusion of objects. Such names as those of La
Lande, Reaumur, Maraldi, De la Caille, Daubenton, d’Alembert, Condamine,
Adanson, Daniel Bernouilli, Borda, Fontaine, Haller, Lavoisié®, and others,
thickly strewn through the Memoirs of the Academy of Sciences of that time,
satisfactorily refute any presumption that it had ceased to merit or maintain its
hold upon public respect or its title to the lasting admiration and gratitude of
mankind. ‘The writer of the article might have quoted other sarcasms directed
to the same object with the epitaph. 'Thas, when Voltaire was asked in Eng-
land respecting the Memoirs of the Academy, he replied: ‘It writes no me-
moirs, but it has published sixty or eighty volumes of compliments.’ And
the above-named Piron had said that a discours de reception at the Academy
ought never to exceed three words ; “ that the recipiendary should say, ‘ Many
thanks, sirs;’ and the director should reply, ‘ Sir, there isno occasion for any.’”
But all these taunts were aimed at a different academy from the above ; at what
Voltaire termed the “ academie de paroles,”’ as he styled the other the “ acad-
emie de choses.” Yet the petulance of satire can scarcely lead us to believe
that even the Academie Francaise, which still numbered among its members
a d’Alembert, a Buffon, a Voltaire, had sunk so low as to render admission
into its ranks “a subject of contempt and derision.” True enough that the
vices of its regimen, as exhibited by Arago, had done much to reduce it to a
state of servility and imbecility. “ Until 1758, the subjects for prizes proposed
by this Academy exclusively related to questions of devotion and morality.
‘he eloquence of the competitors was thus called upon to exercise itself suc-
cessively on the science of salvation, on the merit and dignity of martyrdom,
on purity of mind and body, on the dangers which lurk amidst seeming secu-
rity, &e. The Ave Maria even was paraphrased. Each discourse was to be

Go

56 ACADEMY OF SCIENCES OF PARIS.

terminated by a short prayer. Accepted papers were never allowed to reach
the public until they had been submitted to the rigorous censorship of four
doctors of theology; nor could the approbation of the high dignitaries of the
church which the distinguished assembly always counted among its members
secure any dispensation from this humiliating formality.” (Arago; Eloge de
Bailly.)

The interference of an external influence foreign to the spirit and embarrass-
ing to the ends of the institution certainly existed also in the case of the
Academy of Sciences; but here it seems to have been limited to courtly in-
trigues for the admission or exclusion of particular persons. Arago shows us
in his Autobiography that he piqued himself in no small degree on having some-
times successfully disconcerted the unauthorized procedures of a minister, and
even on one occasion thrown discountenance on the advocacy of the king.

The official term of Condoreet as perpetual secretary conducts us to the
period when, in common with other learned bodies of the kingdom, the Acade-
mics of Paris fell before the levelling force of the Revolution. Their suppres-
sion took place in 1793. They may be considered to have been revived by
an ordinance of 1795, in an associated form, under the name of the National
Institute, in which a distinction into classes superseded the ancient name of
Academies. Of these classes there were three: 1. The class of the physical and
mathematical sciences; 2, that of the moral and political sciences; 3, that
of literature and the fine arts. This latter class represented as well the Acad-
enie francaise as the former academy of inscriptions and that of painting. The
_name of National Institute has survived all modifications of form and changes
* of dynasty.

M. Flourens thinks it worthy of note that on the day (1 pluvidse an IV)
when the National Institute held its first public sitting, Cuvier read before it
his memoir on the species of fossil elephants compared with living species. “In
this memoir,” he observes, “the illustrious savant announces, for the first time,
his views respecting lost animals. Thus on the very day when the Institute
opened the first of its public sessions, there was opened at the same time the
career of the grandest discoveries made by natural history in our age; a sin-
gular coincidence, and one which the history of science should preserve.” It
is more to the present purpose to remark, that after a few temporary appoint-
ments, Cuvier was chosen perpetual Secretary in the first class for the section
of physical sciences, and that M. Vlourens survives to this day as his only and
immediate successor in that section, thus presenting through this long space of
time a permanence of official tenure which, taken in connexion with the in-
stances of b'ontenelle and Fouchy, must argue that in philosophical labors there
is at least nothing unfavorable to relative longevity. The order of succession
as perpetual Secretaries in the other section—that, namely, of the mathematical
sciences—is Delambre, Joseph Fourier, Arago, Elie de Beaumont, (1854.)

In 1803, Napoleon, who was then First Consul, prescribed some modifications
in the form and probably in the spirit of the Institute. The class of moral and
political sciences was suppressed, and of the remainder a fourfold division
was formed: 1. The class of physical and mathematical sciences; 2, that of
French language and literature; 3, that of Ancient history and literature ;
4, that of the I'ine Arts. Having thus eliminated the suspicious element of
ideology, Napoleon continued, as he had always done, to watch with judicious
and lively interest over the prosperity of the Institute, of which he was him-
self a member, often seleeting the objects of his trust and favor from its ranks,
and exacting from it reports upon the progress and prospects of science, which
he received in person with a distinction and eclat not usually bestowed upon
such subjects in the courts of princes. This was quite conformable with the
spirit which had ted him in the campaigns of Egypt to sign himself in his

~

ACADEMY OF SCIENCES OF PARIS. oot

orders of the day as “member of the Institute, commanding-in-chief the army
of the East.”* (Arago; Eloge de Fourier.)

Upon the Restoration a royal ordinance of March 21, 1816, again conferred.
on the classes of the Institute their dncient title of Academies. 'The first class
‘once more became the Academy of Sciences; the second, the Academie fran-
caise; the third, the Academy of Inscriptions and Belles-Lettres; the fourth,
the Academy of Fine Arts. Finally, in 1832, Louis Philippe reinstated the
proscribed class under the title of the Academy of Moral and Political Sciences,
and to the five sections, of which this was at first composed, the present Em-
peror bas added a sixth, devoted to politics, administration, and finance. 'The
Institute, it is stated, now consists of 223 members, 31 associates, 228 corre-
spondents, 7 secretaries, and 35 free academicians. :

The commemoration of deceased members by a notice apart, formed, as has
been seen, an early, and has remained a constant part of\the academic obser-
vances. Of these notices it is said, by one of those most distinguished for their
composition, that, equally with the memoirs of the Academy, “they were de-
signed to have truth for their basis and their object.”’ And although, as Cuvier
remarks, it be difficult to observe the cold impartiality of history, when the
hand is resting, as it were, on the funeral urn of an instructor or friend, yet the
general candor with which they are written, the equity with which merit is
assigned even if censure is softened or evaded, cannot in most instances fail to
secure the confidence of the reader. There is but little, perhaps, in English
literature which resembles them, for it has been often complained that the bio-
graphical notices of literary and scientific men are here but too frequently
either limited to dry catalogues of writings and discoveries, or spread through
such wastes of commentary and circumstance that the traits of individuality
lose their distinctness and vivacity. “It seems,’’ says an English reviewer,
‘“‘to have been an established tradition in our literature that the ‘life’ of a man
of letters must necessarily be a dull book.’’ ILowever this may be, the writers
of the Eloges, from Fontenelle to Arago, have certainly contrived for the most
part to fill the comparatively narrow outline to which they are limited with
such sharp and well-defined features of personality as to maintain an ever-
varying interest in the subjects themselves as well as in their labors. There
is here no gallery of scientific masks, but a succession of distinct and animated,
if reduced, portraitures. The scientific value of the Eloges, on the other hand,
seems to be assured as well by the ability of the distinguished savants to
whom we owe them, as the character of the body to which they were addressed ;
and as the series extends from the middle of the seventeenth century to the
present day, they are well calculated to show the successive steps and “devious
paths”? by which experimental philosophy has advanced to the “bright emi-

.nence”’ from which it now challenges the confidence and admiration of the
world.— TRANSLATOR.

*“T can understand and appreciate the grounds of your refusal,’ said Napoleon one day
to a member of the Institute who had just declined a proffered office. ‘‘ You wish to devote
yourself entirely to your pursuits. Well, I myself, had not fortune called me to preside over
the destinies of a great people, think you that I would have haunted the bureaus and
saloons in quest of official favor from any quarter as minister or ambassador? No; I would
have thrown myself into the study of the exact sciences. I would have advanced in the
path of the Galileos and the Newtons. And since I have constantly succeeded in all great
enterprises, I should have highly distinguished myself by my scientific labors. I should have
left the memory of noble discoveries. No other glory could have tempted my ambition.”
(Arago; Eloge de Thomas Young.)

MEMOIR OF LEOPOLD VON BUCH.

By M. FLOU EENS;

PERPETUAL SECRETARY OF THE FRENCH ACADEMY OF SCIENCES.

TRANSLATED FOR THE SMITHSONIAN INSTITUTION BY C. A. ALEXANDER.

“Dating from the first years of the age of Louis XIV,” says Voltaire, “a
general revolution has been effected in our arts, our genius, our manners, which
must forever serve to mark the true glory of our country. This revolution,”
he adds, “did not stop in France; it extended to England, carried taste into
Germany, science into Russia, and reanimated the languishing spirit of Italy.”
‘The period of which Voltaire speaks was in truth distinguished by the rise of
an honorable and strenuous emulation among all the nations of Europe, and by
an alliance of intellects which, deriving new force from mutual support, no
longer feared to submit to investigation those great and fundamental questions
whose solution might have seemed forever hidden from us.

In Germany, one of those who most contributed to inspire science with
courage for arduous enterprises was Leibnitz. While this rare genius was
meditating the project of endowing his country with a great literary and scien-
tific association, a colony of French savants, driven into exile by the revocation
of the edict of Nantes, came to seek shelter in his neighborhood. Profiting by
this valuable aid, the Academy of Berlin was established. But the course of
its prosperity was short. The reign of William I, the rigorous tactician, who
thought of nothing but war, who measured the merit of his subjects by their
stature, and defined savants frivolous inutilities, supervened. ‘The learned
assembly found itself from that moment discountenanced, and was only restored
to its position under the influence of the great Frederick. ‘This last monarch
practiced no disguise as to his admiration for France, of which he loved alike
the literature, the philosophy, the language, and above all the men of letters,
whom he would fain have lured away to Berlin. In default of Voltaire or
d’Alembert, he took from us Maupertius, and made him president of his
Academy.

Frederick impressed on all the mental activities of his country the ardor
which governed himself. Inlightened by his example, the oldest and most
noble families perceived that to dedicate their sons to the higher objects of
intellectual toil, was at once to reflect honor on themselves and to acquire for
the nation inexhaustible resources of utility and fame. At Stolpe, in the
Uckermark, in the tranquillity of a residence inherited from many generations,
one of these families, which could already point to names illustrious in diplo-
macy and letters, numbered, among an attractive group of brothers and sisters,
« young enthusiast, active and intelligent, but wayward and contemplative,
who, neglecting the usual sports and pleasures of his age, devoted his childish
«dination to the objects presented by the beautiful scenery in which he was
nurturec

MEMOIR OF LEOPOLD VON BUCH. 359

After a preliminary course of instruction, the young Leopold Von Buch, born
April 26, 1774, quitted the banks of the Oder in order to enter, at scarcely
sixteen years of age, upon new and more severe studies. The school of mines
a first step to eeology, was that in which his aptitude and energy received their
earliest development.

Few sciences are at onee go recent and go old as geology. In every age men
have sought to know how the globe they inhabit was formed, and the problem
has always proved highly embarrassing. Hence certain ancient philosophers
were led to solve the difficulty by the very convenient supposition that the
world is eternal. Fortunately, a writer much older than these philosophers,
and, without himself suspecting it, much more learned, has transmitted to us a
singularly faithful indication of the manner in which things had their beginning,
and of the stages by which they have arrived at the state in which we now sec
them. The record of Moses had become, at the end of the X VIIth century, the
theme which exercised all intellects. Stenon, Burnet, Woodward, Whiston,*
applied themselves to the study of the deluge described in Genesis, and thought
that all the changes of the globe might be explained by the effects of that
deluge alone. Licbnitzt was the first to comprehend that previous to the
action of the waters, a still more energetic action, that of fire, must have been
exerted; for all has been melted, all has been liquefied. “And what other
agent,”’ he cries, “what other agent but fire could have been capable of dissolv-
ing those mighty bones of the globe, those naked rocks and imperishable
boulders: magna telluris ossa, nudaque ille rupes atque immortales silices |”

To Leibnitz succeeded Buffon. In his Theory of the eafth, Buffon, as yet,
saw nothing but the action of water; in his system on the Formation of the
planets, he sees nothing but the action of fire; in his Epochs of nature, his best
considered and most ‘perfect work,t he skilfully subordinates the action of
water to that of fire, assigns to each of these agents its part, to every event its
place, to every fact its age; but this admirable book came too late. From the
appearance of the two earlier productions of Buffon, his cotemporaries hac
been divided; some had taken sides for his theory, some for his system. The
first imagined everything to have been formed by water, the last by fire; these
were called Vulcanians, those Neptunians. In England the Vulcanian:
acknowledged as their chiefs Hutton and Playfair,§ in France Desmarets and
Dolomieu.|| ‘The school of Freyberg, where Germany flocked around Werner,§;
became the centre of neptunism. It was here that the young Von Buch
arrived in 1791.

Confided to the care of Werner, he was his favorite disciple, and an inmate
of his house. In long and paternal colloquies, the master, who united with the

/

*Stenon: Nicolai Stenonis de solido intra solidum naturaliter contento dissertationis
Prodromus. Llorentia, 1669.

Burnet: Telluris theoria sacra, etc. Londini, 168).

Woodward: An essay towards the natural history of the earth, ctc. London, 1695.

Whiston: A new theory of the earth. London, 1708.

{ Leibnitz: Protogaa, sive de prima facie telluris, etc. (Actes de Leipsick,) 1683

¢ Further dev clopments on this point may be seen in the author’s Histoire des travaux et
des idées de Buffon.

§ Hutton, (James, ) born 1726, died 1797: Theory of the earth, with proofs and illustrations,
in four paris. Edinburg, 1795. This work is a reproduction of two former E ssays or Me-
moirs, published, the first in 1785, the second in 1788.

Playfair, John: Illustrations of the Huttonian theory of the earth. Edinburg, 1802.

|| Desmarets, (Nicolas, ) born 1725, died 1815, was the first who, in France, conceived the
system of vulcanism.

Dolomieu, (Deodat-Guy-Sylvain-Tancrede de Gratet de,) born 1750, died 1801, was the
geologist w ho, before Von Buch, most advanced the theory of voleanoes and that of the
action of fire on the globe.

4 Abraham- Gottlob W erner, born 1750, died 1817, influenced more than any other man of
his time the progress of geology.

360 MEMOIR OF LEOPOLD VON BUCH.

genius of method the charm of eloquence and the seductiveness of good nature,
found himself happy in an opportunity of communicating to a quick and pene-
trating intellect the treasures of knowledge which had been accumulated 2
long years of meditation and observation, and which a disinclination for writing,*
only to be accounted for by his happy facility of speech, left him no other
means of imparting.

About the same period with Von Buch, there arrived at the school of Freyberg
several young men with whom he naturally entered into relations of friendship.
These attachments, so easily contracted in youth, so often dissolved amid the
conflicts of life, were with him as enduring as life itself. No similarity of aims
ever disturbed the uniformity of his regard for Charles Friesleben,} and through-
out his whole career his love and admiration for Alexander Von Humboldt, who
to a less candid nature might have seemed a dangerous rival, were as unre-
stricted as they were disinterested.

At eighteen years of age he made a first trial of his strength by publishing a
descriptive mineralogy,< trom the motto of which we learn the boldness of his
aspirations : “ W hat 1 is new,” he says, “‘extends, what is great exalts, the circle
of our observation.”’ Soliciting, two years after, employ ment in the service of
mines, he addressed to the Minister Heinitz a second essay, equally evincing
the early penetration of his intellect: ‘What I have sought to prove,” he says,
‘is the possibility of finding constant laws according to which the formation of
crystals takes place.” A royal scholarship, with a commission for directing the
working of the mines, was speedily conferred on him, and imposed engagements
whose restraints *he submitted to for three years. But, independent in spirit and
in fortune, with a rich future before him, knowing as yet no explanation of the
great phenomena of the globe but those which the school of Freyberg admitted,
and too clear-sighted to content himself with these, he threw aside the shackles
of the artificial world with the badge of the engineer and resumed his liberty.
This fortunate breach of discipline, “the first aw akening of genius, was silently
connived at by government, to the subsequent advantage of both parties.

Of the disciples of Werner§ it has been said, “that they dispersed them-
selves through all countries, from pole to pole, in order to interrogate nature
in the name of their master.” Von Buch was pre- -eminently one of those inde-
fatigable interrogators of nature. He set out in 1797, diree ting his course
towards the Alps, wandered for some time in the mountainous districts of Styria,
passed a winter at Salzbourg,|| and then turned his steps towards Italy. He
wished to visit the places where violent commotions have ruptured the crust of
the earth and opened it, according to his own expression, to the eyes of observers.
It was here, however, that his confidence in the infallibility of his school was
destined speedily to be shaken.

From Perugino, the young Neptunian already writes: ‘Here the different

species of rocks seem to have been overwhelmed by chaos itself. I find the
beds of porphyry above the secondary limestone, and the micaceous schists
above the porphyry. Does not all this threaten with ruin the fine systems
which determine the epoch of formations?’ In a series of letters to his friend

* The writings left us by Werner are few and very short: Treatise on the characters of
neinerals, (1774, ) a work in which the spirit of Linnzeus is predominant; Classification and
description of mountains, (1787;) New theory of the formation of mineral and metallic veins,
(1791,) a work of a high order, in which the genius of observation and method is everywhere
visible.

+ Johan Karl Friesleben, (died 1846,) captain of mines at Freyberg, and known by his geo-
logical writings on the gypsum of the Val-canaria, Formations of Thuringia, &c.

i Materiaur pour une description mineralogique de la contrée de Carlsbad. Freyberg,
1792

§ See the excellent work of d’Aubuisson de Voisins; Traité de geognosie, etc., 1819.

| A sojourn shared by his friend Humboldt, and memorable for the experiments of the latter
on meteorology and eudiometry.

MEMOIR OF LEOPOLD VON BUCH. 361

de Moll, we see that Italy appeared to his youthful and enthusiastic imagination
a promised land; and that though science is always in his thoughts, nothing
escapes notice, and all sorts of observations gratify him. If the Albanian hills
constrain him to modify the ideas which he had brought with him respecting
the insignificance of volcanic effects, yet, in the midst of constantly recurring
alarms for the system of his master, he pleases himself with the description of
the beauties unfolded before his eyes: ‘Nature,’ he exclaims, “seems here
inexhaustible in the creation of delights which spring up at every step. Whoever
has not seen the sun set in the sea while his rays gild the cupolas of the eternal
city, whoever has not watched on Lake Nemi the alternating play of the light,
can form no conception of the charm of those regions.” A tone such as this
reveals the man for whom, during a long career, study and the seductions of
travel are to be inseparably linked, and who in research is intent only on that
which is exalted and aggrandized by its union with the emotions of the soul.

Arriving at Rome, he there observes the doubtful traces of extinet volcanoes,
and his disquietude increases. ‘Iam lost,” he says, “in the contradictions
which seem to have been here accumulated. One knows not what to believe,
nor even if it is permitted to trust one’s own eyes.”

T’o him Vesuvius had always held out the promise of arevelation. At length,
after several delays, he saw it, on the 19th of February, 1799. “TI arrived,” he
tells us, “by way of the fair plains of the Campania; a fog which covered the
horizon suddenly vanished, and before me rose sublime the double peak of Ve-
suvius crowned with eternal flame. There it is! was the involuntary ery which
an expectation so keen and so often disappointed drew from me; while the
cloud in lifting itself seemed to aspire to unite the vast mountain with the
heavens.”

On approaching Naples, the young German, brought into contact with a
vivacious and impassioned population, felt a natural surprise at the singular
contrast which the brisk petulance of the inhabitants of these climates forms
with the phlegmatic earnestness of his native Germany: “Here,” he says,
“where language stems scarcely the competent organ of expression, where
gesture seems the true language, how does everything recall the idea of that
mysterious fire which we know only by its effects, and which strikes us in so
unexpected a manner.’’

Vesuvius, whose mysteries he so earnestly longed to penetrate, baffled him
on this occasion with delusive hopes. He brought away little but a presenti-
ment of the vast labors which lay before him: “I have seen the crater and
descended it,” he writes, “but I have realized nothing but a religious horror
which certainly gives me no insight into the connexion of causes and effects.”
Following the currents of lava, he retraces that which filled Naples with dismay
in 1767, as well as the fiery torrent which some years later swept away the
town of Torre del Greco and spread far into the sea; and animated by recitals
stZl impressed with terror, he paints the effects of this fearful unloosening of
subterranean forces with a poetic energy which recalls the celebrated letter of
the younger Pliny. From this first expedition our young savant was taught to
comprehend that the study of strata tranquilly deposited by the waters is not, as
was thought at Freyberg, the whole of geology, that nature reveals herself in crises,
and it is only at such epochs that we can hope to detect secrets which were
otherwise impenetrable.

Von Buch left Italy, where fire in activity spreads its ravages, only to pass
into France, where Auvergne offered him the most suitable of theatres for the
study of extinct voleanoes.

Buffon had seen in volcanoes nothing but a congeries of sulphurs and pyrites

362 MEMOIR OF LEOPOLD VON BUCH.

situated quite near the summit of mountains.* The sagacious and patient de Saus-
sure had too long meditated and suffered among the snows of Mont Blane to con-
cede much infiuence to mountains of fire. Werner, averse to what might disturb
the regular order of nature, which he had elaborated, and interrupt the tranquil
flow of his instructions, accepted volcanoes but as local and limited accidents.
it was thus-that matters stood, and would perhaps have long stood, had not
two travellers, who happened to be detained on the road to Moulins, been
struck at observing the great difficulty experienced by a mason at work near
them, in breaking the stones with which he was constructing a fountain: their
hardness, color, and porous structure recalled to one of the observers the lavas
of Vesuvius. ‘“ Whence do you bring these stones ?”’ he asked. “‘ From Volvic,
near Riom.”’ ‘“ Volvic! Vulcani, vicus; there must have been a volcano
there,” said our celebrated naturalist, Guettard,t to his friend Malsherbes ; ‘let
us take the road to Auvergne.” ‘This they did; it was in 1751. Guettard
discovered a whole chain of extinct volcanoes, and revealed to his fellow-citi-
zens that they trod a soil once on fire; the lavas, the cinders, the scoriz, the
mountains, with their craters, all lent confirmation to the fact. 'The unexpected
announcement was reccived, we are told, with astonishment, and even with
alarm.

Twelve years later, the practical and sagacious Desmarets, in the course of
one of those excursions in which he traversed the whole of France on foot,
made a visit to the Puy de Dome, and clearly distinguished the pillars of
black stone, whose figure and position struck him with their resemblance to
what he had read respecting basalts and giant causeways. In their regularity,
these columns bore the indications of a melted product; +t and further investi-
gation left no doubt on the mind of Desmarets that they had been cast by the
action of fire.

_ * Perpendicular fissures, some larger, some smaller, have doubtless been formed in vast
numbers in the body of the mountain. The rain, of course, penetrated into all these fissures,
and taking up or dissolving whatever substances were capable of being thus acted on, have
formed pyrites, sulphurs, and other combustible materials ; and when, in a long succession
of ages, these had accumulated in immense quantity, fermentation and conflagration have
taken place, producing the explosions and other effects of voleanoes. Perhaps, also, there were
masses of these mineral substances already existing before the rains could reach them, but
whenever openings or crannies, by which the. water and air could penetrate, have been
formed, ignition has taken place in the inflammable matter and a volcano has been the
result.” —Buffon, 1, p. 287. ‘‘ The fire of the volcano comes rather from the summit than
from the lower depths of the mountain.”—/d., 1, p. 285. (The author cites here and else-
where his own edition of Buffon, just published in 12 vols. 8vo.)

t Guettard, (Jean Etienne,) born 1715, died 1786: Memoire sur quelques montagnes de
la France qui ont eté des Volcans. Mem. del’ Academie des Sciences, 1752.

t That the columns were almost always found at the termination of long courses of lava
which had themselves issued from craters still discernible, carried conviction to the mind of
Desmarets. ‘‘ In 1763,” he says, ‘‘I traversed a part of Auvergne, where traces of voleanoes
are to be seen, and particularly from Volvic to the Monts Dor. On the route from Clermont
to the Puy de Dome, I perceived prisms of a black and compact stone, like that which cov-
ered a great part of the surface, the prisms resting on a bed of scorize. It was evident that
they pertained to the crust of black stone enveloping the high plain which leads to the foot
of the celebrated mountain. When I considered the inconsiderable thickness of this crust
established on a bed of scorice and overlying a mass of granite which had undergone no
action of fire, the idea at once occurred to me that here was the product of a current which
had escaped from a neighboring voleano. Proceeding on this idea, I ascertained the lateral
and extreme limits of the deposit, and still found the prisms, presenting in the perpendicular
section their faces and angles, and on the surface their bases perceptibly distinct from one
another. I was thus decided in the belief that the prismatic basalt belongs to the products
of volcanoes, and that this constant and regular form is the result of the state of fusion in
which the lava once existed. There can, I think, be no doubt that the groups of prismatic
columns in Auvergne pertain to the same conformation with those of the county of Antrim,
in Ireland, and that the constant and regular form is in Antrim the result of a cause similar
to that which announces itself in so uniform a manner in Auvergne.”—Desmarets : Memoire
sur Vorigine et la nature du basalte a grandes colonnes polygones, &c.—(Mem. de l’Acade-
mie des Sciences, 1771.)

MEMOIR OF LEOPOLD VON BUCH. 363

The igneous origin of basalts, the action of fire, then, was established, but
where did this formidable agent reside? It was another French geologist who
ventured for the first time to answer, at great depths beneath the solid crust of
the globe ;* a revelation which we owe to the genius of Dolomieu, so severely
tried with misfortune, but endowed sometimes with an utterance which might
seem little less than inspired.

These extinct craters and melted basalts, these fires at profound depths,
strangely interfered with the system of the excellent Werner, who would ~
admit of nothing beneath the granite, and could see nothing above it but deposits
of aqueous formation.t It was a step, therefore, towards independence when
Leopold von Buch ventured, first among the German Neptunians, into the very
focus of vulcanism, to assure himself whether Auvergne, as it was described,
really pertained to the existing world. The surprise he had felt at Perugino
was here, of course, redoubled. Here, not nature alone offered him her guid-
ance, but the men of genius also who had preceded him. What might not this
young and vigorous intelligence hope, if successful in recovering the clue of
those grand ideas with which these localities and phenomena had inspired his
predecessors !

His exploration of Auvergne was persistent and profound. He applied to
it all the resources of his mind, and may be said, by this forcing process, to
have here conceived the germs of all the lofty views to the development of
which his after life was consecrated. The account of this visit is filled with
the traces of hesitation and of effort. At the sight of the basalts, he exclaims,
‘«‘ How is it possible to believe in their igneous origin when we recall the rocks
which accompany them in Germany; and yet here how is it possible to doubt
of it?” In view of the subverted and displaced strata, he says: ‘I see the
whole edifice fall to pieces which, by a sweeping arrangement of the series of
rocks, gave us the structure of the world at the same time with its history.”
Contemplating that long chain of hights (Puys)t which stretch in succession
from the Mont Dore, he is struck with a preconception of the possibility of
the upheaval of the entire mass of these volcanoes : ‘“‘ What, indeed, prevents
us,” he asks, ‘from conceiving the whole mass of the Mont Dore to have been
thus lifted up?”

Voltaire tells us that a Frenchman who, in his time, had passed from Paris
to London, would find things not a little changed. He had left the universe
a plenum; he would find it a vacuum. He had left behind a philosophy which
explained everything by impulsion; he would find one which explained every-
thing by attraction. When our young savant passed from Germany into
France, something of the same sort had occurred to him.

* “The first conclusions to be drawn are, that here the volcanic products pertain to a mass
of materials which differ from granites, and are situated beneath them; that the volcanic
agents resided under the granite and wrought at depths very far below it.”—(Dolomieu:

teport made to the National Institute on his travels in the years }798—99.) ‘To be as exact
as possible,” adds Dolomieu (as if alarmed at the temerity with which he had overstepped
received ideas,) ‘‘I have taken care always to use the adverb here, in order to restrict to the
precise localities which furnished my observations the conclusions I draw from them. But
there is reason for believing that the same is the case with all other volcanoes, whatever may
be the nature of the surrounding formations; that it is at great depths within or below the
solid crust of the globe that the voleanic agents as well as the bases of all their ejections
reside, and that it is there that lie concealed the causes which supply the flame attending the
eruptions and which produce the fluidity of the lavas.”

There is nothing in geology more celebrated or which longer prevailed than the system
of Werner: a universal and tranquil sea deposits, in vast masses, the primitive rocks, dis-
tinctly crystallized, in which at first silex predominates. The granite underlies all; to this
succeeds gneiss, which is but a granite beginning to foliate; by degrees clay gains the
preponderance; schists of different sorts appear, &c.

Werner never quitted Saxony, and it may be said of him that he was too hasty im con-
cluding that all the world was constituted like his own provinec.

$ | Puech or Puick, an old Aquitanian word, signifying mountain.—TR. ]

364 MEMOIR OF LEOPOLD VON BUCH.

Werner had pronounced that all rocks, without exception, porphyry, granite,
even basalt, were the product of water; here the granite, the porphyry, the
basalt, bore irrefutable testimony to the action of fire. Werner had taught that
the superposition of strata had observed always the same order; the granite
below the gneiss, and porphyry below the limestone, &c. In Italy and Au-
vergne the whole order was reversed; in one place the granite, elsewhere the
porphyry, occurred above the limestone. Werner had said that the seat of
volcanoes did not descend below the limit of the coals, the source, as he taught,
of the materials which maintain them. Here the focus of the voleanoes showed
itself beneath the deepest rocks, the porphyry, the granite, the terrestrial en-
velope. Werner, in fine, had seen in voleanoes only accidental and local phe-
nomena of comparatively small potency. In Auvergne everything demon-
strated the extent and power of those hidden and profound forces which had
sufficed to elevate immense rocks, and even entire mountains, such as the Cantal
and the Monts Dore.

The exploration of Auvergne, in opening to Von Buch a whole series of
sublime views, impressed him with the necessity of calling new resources to his
aid. It was said of him, by an Englishman, “that he went everywhere to take
the measure of those who cultivated his favorite science;’’ and what he had
learned respecting the sagacity of the French savants seems now to have inspired
him with the desire of taking their measure. He went to Paris, formed con-
nexions there, and among others with Haiiy, the kindness of whose reception
he acknowledges in terms which show how highly he prized the words of en-
couragement extended to him by this great master. Tho museums, the collec-
tions, the libraries, were no less objects of eager interest than the conversation
of accomplished men. Levying contributions from every source, he referred all
to his one great task of active labor and incessant meditation. Among the
common elements of character, vanity was one in which he seemed wholly de-
ficient. Impelled to constant observation as if by a necessity of his nature, he
may be said, on leaving Auvergne, to have made but one tour, but it was a
tour which lasted his whole life. ‘What mode of conveyance do you prefer?”
he was asked by somebody who thought himself an observer. “What!” re-
plied M. Von Buch, leaning on his inseparable umbrella, “you do not know how
a geologist ought to travel?’ As regards himself, he might have been seen
traversing afoot, at one time, the entire chain of the Appenines; at another,
that of the Alps ; passing, in the same way, from the craters of Vesuvius to the
mountains of Scotland; from Etna to the snows of the polar circle; again at
his favorite station of the Monts Dore, on his route to Paris, where the society
of kindred minds might delay but could not detain him. He gave no notice of
his arrival, and still less of his departure. A savant, surprised at receiving a
visit from kim and going to return it, would not improbably find that he had
again disappeared, and learn by a letter from Naples, perhaps, or Stockholm,
where it would be necessary to inquire for M. Von Buch. At Paris, one day,
a geologist of note going to see him, met him on the threshold of his hotel, um-
brella in hand. It wasabad sign. ‘“ Youare going out; allow me to accompany
you.” “Willingly.” “But where are you going?” “To Berlin.”

Setting out, as was his wont, every spring, he took with him no companion
but the faithful one just mentioned; no guide but his impulse; no baggage but
his book of notes, his barometer, two or three favorite volumes, and above all,
that indefatigable pick to whose blows so many rocks have resounded ; all con-
tained in the vast pockets of a double vestment, which, always the same and
proof against every change of temperature, generally bore the marks of this
manifold service. If night overtook him, he directed his steps to the nearest
town and presented himself at the best hotel, where his odd equipment could
not but lead occasionally to singular mistakes. But, as the fragrance of his
probity and kindness survived all other impressions, these strange apparitions

MEMOIR OF LEOPOLD VON BUCH. 365

of his came at last to be regarded, by the villagers among whom he passed,
somewhat in the light of those of the benevolent genii of the old German legends.
Each season saw him return, at a stated time, to the paternal manor, where a
brother, who was blind, awaited him, and whom he would allow no one but
himself to conduct to the waters of Carlsbad.

In 1804, Vesuvius having shown some signs of disturbance, he repaired
thither anew; this time in company with MM. de Humboldt and Gay Lussac.
The combined observations of these eminent men resulted in a scientific expo-
sition of all the effects associated with volcanic eruptions. Vibrations of the
earth were recognized as their inseparable concomitants; the nature of the
gases exhaled, the composition of the lavas, the force, development, and dura-
tion of these terrible phenomena were all, for the first time, submitted to a
discriminative examination.

Nominated, in 1806, a member of the Academy of Sciences of Berlin, Von
Buch read, on the occasion, a discourse on the progression of forms in nature.
The philosophic view of the succession of beings had been advanced by Buffon,
and the recent labors of Cuvier had furnished a wonderful commentary. Ger-
many was struck with admiration at these sublime views, derived from France.
In this discourse the author paints the successive gradations of the creation ;
inorganic bodies serving for elements in a world which is preparing for animated
beings; animated beings taking their place one after the other, from the most
simple up to the most complicated; up to man, the last term of the progress,
whose appearance suggests these striking words: “To the existence of this
being, the freest and most exalted of all, a vast concourse of physical causes
was necessary. He alone encompasses the globe from one pole to the other ;
detaches himself, by an internal force, from matter; elevates himself above it,
and, this achieved, who shall presume to trace for him a limit?”

Some thirty years before the date of these expressions the famous book of
Pontoppidan had, in some sort, revealed to Europe countries which belong to
it, but which were then as little known as certain tracts of India or America.
The soil of the Scandinavian peninsula—at that time a virgin one, as regards
researches—held out to Von Buch a promise of new impressions. No sooner,
in fact, does he arrive at Christiana,* than he finds mountains of porphyry
resting on limestone, and enormous masses of granite supported by fossil-bearing
strata. ‘Thus was the last blow given to his early faith, and from this time he
thought no more of defending Neptunism.

He devoted two years to a study of the formations of Sweden and Norway.
Proceeding with his accustomed energy, sometimes by land, sometimes by sea,
he explored the singularly indented coasts of the Scandinavian peninsula,
ascending as far as the barren rocks of the North cape. He was occupied with
the solution of an imposing problem.

For more than a half century the inhabitants of the coast thought they had
observed a gradual depression of the level of the sea. At the suggestion of the
celebrated astronomer Celsius there had been marks cut in the rocks at Gefle
and Calmar. Linnzeus had himself traced a level on a block, which he deseribes
with botanical precision. Here a maritime city having become an inland one ;
there an arm of the sea having been transformed into a highway ; and all tra-
dition concurring, the people of the country could no longer doubt of a diminu-

* Porphyries in huge masses, in mountains even, are seated on a calcareous, shell-bearing
rock. These porphyries again are covered by a sienite almost entirely composed of feldspar
in large beds, and this sienite is buried under a granite which is in nowise distinguished, as
regards its composition, from a granite of the most ancicnt formation.

‘These phenomena, which give undoubtedly great geological interest to the environs of
Christiana, have been observed with much sagacity, and described by M. Haussmann, pro-
fessor at Gottingen, in a special memoir, inserted in the journal of the Baron de Moll.”"—( Von
Buch, Voyage en Norwege et en Laponice. )

366 MEMOIR OF LEOPOLD VON BUCH.
.

tion of the waters. ‘ How singular a phenomenon !”’ exclaims Von Buch; ‘and
to how many questions does it give rise?’ After due consideration he adds:
‘It is certain that the level of the sea cannot subside; the equilibrium of the
waters forbids it. Yet the phenomenon of their retreat is no less unquestion-
able, and there remains but one admissible idea—that of a general upheaval of
the land from Frederieshall to Abo, and perhaps to St. Petersburg.”’

When this striking idea was announced, the full importance of its bearing
could not be at once foreseen. 'The demonstration of an upheaval of part of
our continent is the discovery which has most strongly contributed to fortify
the new theory of volcanoes and that of the origin of mountains, while it has
given the most general insight into the continual effort, the incessant reaction
of the interior of the globe against its envelope.

At the extremity of the peninsula other phenomena awaited the observer.
The eternal snows, which hover in an atmosphere still capable of developing
organized beings, and which, in the torrid zone, maintain themselves at the
level of the summit of Mont Blane, occupy, on the coasts of Finmark, hills
scarcely more than five or six times the height of our tallest buildings. Here
our ingenious Regnard had once essayed to brave the rigors of a region then
deemed inaccessible, and, in view of the interminable wastes of ice, had described
himself in verses which, he says, “were destined to be read only by the bears,”
as having reached the end of the world:

Hic tandem stetimus nobis ubi defuit orbis.

Much further than this erd of the world, and beyond the polar circle, after
the long and dismal winter, M. Von Buch was witness of that boreal summer,
so curious and so little known, which he calls the season of day—a day which
lasts for two months. Writing on the 4th of July, he says: “The continual
presence of the sun and constant serenity of the air give to the days of these
countries a peculiar charm. At the approach of midnight, when that orb pro-
longs its course towards the north, the whole region enjoys a perfect calm; the
clearness is at every moment the same. It is only by the sinking of the mer-
cury that the advance of the evening can be ascertained. After no long interval
all nature begins once more to be reanimated; the mists rise from the surface
of the earth; small waves on the waters show that the air which comes from
the north presses with more force towards the south. The sun ascends from
the horizon, its rays operate, and the murmur of rivulets, swelled by the melting
snow, sensibly increases, until, through the effect of another night, one feels
nothing but a soothing warmth.”

Nor is Scandinavia less characterized by its inhabitants than its physical
phenomena. Its icy waters and its lichens suffice to sustain the agility and
vigor of the reindeer, that noble and docile companion of the nomadic life of
the Laplander, a specimen of our race who bears in his stunted form and rustic
manners the impress of the zone into which he has ventured to introduce our
common humanity. By his side, but with marked differences, appear the Nor-
wegian of the coasts, disdainful of his shrunken neighbor, and the agricultural
Finn, who, in his softened manners, has carried civilization to the limits of the
habitable world, and even aspires to borrow from us our most refined enjey-
ments. ‘I have seen,” says Von Buch, “in a town near the North Cape, a
public library, in which, by the side of the Danish poets, appeared the master-
pieces of Corneille, Moliere, and Racine.”

As a scientific authority, Von Buch now stood so high that he might well
feel conscious of being a master in the field of higher generalizations, a field so
vast and so rarely attained. His return was greeted with respect by his
country»his academy, by learned Europe in general. Recurring to the theatre
of his earlier labors, he traversed, for several following years, the mountaim
chains of Central Europe, with an attention always fixed on the grand ideas

MEMOIR OF LEOPOLD VON BUCH. 367

which he had propounded, namely, that the disorder of the primitive strata of
the globe pertains to a profound subterranean cause which is connected with
voleanic action; that not only the basalts but all crystalline rocks have issued
from the earth in the state of lava, and that to the reactions of the earth are
to be referred the elevation of mountains and that of entire countries,* such as
Sweden.

In the winter of 1814, while absorbed in these thoughts, he found himself at
London, as he might at times be found everywhere, and there encountered an
accomplished Norwegian, the botanist Smith. ‘Our conversation,” says Von
Buch, “ happened to turn on the facility with which one may transport himself
from that capital to almost every known region, and the desire of profiting by
it became so strong that we presently resolved to set out for the Canary
islands.”’ A fortunate resolution, which has endowed geology with a work
that will remain the mark of one of its most important advances.t

The Canary islands had been already visited by skilful observers, among
whom we may distinguish one of our former and most valued colleagues, M.
Cordier, the continuer of Dolomieu ; but hitherto they had only been studied
for themselves. Von Buch studied them in subordination and with reference
to his gencral conceptions.

His book is composed of two parts. The first embraces all the details of
description: the study of rocks, elevation of mountains, variations of climate,
&c. In the second and most important, the author sets forth, in a few pages,
equally admirable for precision of language and fullness of information, his
whole theory of voleanoes; the result of long and critical observation of what
is most general and constant in those grand but hitherto mysterious phe-
nomena.

After succinctly defining a voleano to be ‘‘a permanent communication be-
tween the atmosphere and the interior of the globe,’’ he distinguishes the effort
which elevates from the effort which ruptures ; the first gives him what he calls
the crater of elevation, the second the crater of eruption. He shows that in
each voleano there is a central point around which the eruptions take place,
aud that this central point is always the highest summit—the peak—of the
volcano. He.discerns, further, a common action between all the volcanoes of
the Canary islands, connecting with the peak of Teneriffe the eruptions of the
Isle of Palma, and these last with those of Lancerotte ; for these eruptions are

*Tt would be more exact to say the elevation of entire countrics and of mountains; for, ac-
cording to Von Buch, it is the red porphyry which in the first instance elevates countries or
continents, and the augitic, the black porphyry, which transpierces tho red porphyry and
elevates the mountains.

‘“The upheaval of the pyrogenic porphyry is posterior to the formation of the red sand-
stone and of the calcareous strata; but these sandstones are essentially connected with the
formation of the red porphyry, and can scarcely be separated from it. it follows that the
pyrogenic porphyry must have pierced the red porphyry as-well as the sandstone, and to have
pierced it, must have raised up this porphyry itself.’—Von Buch: Lettre @ M. de Humboldt.
renfermant le tableau gcologique du Tyrol meridional, 1822.

‘From these considerations, I should not have been surprised to see, somewhere in the in-
terior of these valleys, pyrogenic porphyries below the red porphyry. I have, indeed,
sought for them in the whole extent of this last formation, but almost everywhere without
success. I was more fortunate in descending the valley of the Avisio. Aiter having been con-
stantly proceeding on quartz-bearing porphyries as far as Cembra, at some leagues above
ihe opening of that valley, I recognized below that place, and at the edge of a kind of plain,
a very considerable mass of the pyrogenic formation, whose black color contrasts singularly
with the red of the prevailing quartz-bearing porphyry, and which is decidedly distinct trom
the latter. It is evidently a rock, whose mass pertains to the formation of the pyrogenic
porphyry. Its aspect clearly shows that it is engaged in the red porphyry, except towards
the base, where it is connected, probably, with a mass of the same nature, which extends un-
der all the mountains of the Alps.”—Ibid. =

+ M. de Humboldt, in reference to this work, said: ‘‘ Leopold von Buch is the first who has
recognized the interconnexion and mutual dependence of yolcanic phenomena, and has
thaie>y proved himself the greatest geologist of our epoch.”

368 MEMOIR OF LEOPOLD VON BQOCH.

all associated, (so/idazres,) and one never commences until the other has ceased.
As, in hands so skilful, the thread of analogy, once seized, is never broken,
from the volcanoes of the Canaries he passes to those of the entire globe,
and ranges them all under two classes, central volcanoes and volcanic chains.
The first form the centre of a number of eruptions which take place around
them ; the second are all disposed in line, each following the other in the same
direction, like a great rent or fissure of the globe; being, as Von Buch adds,
probably nothing else but such a rent. From these isolated points of rock,
elevated by fire, transporting his view over the innumerable isles everywhere
seattered in the ocean, he combines them all under the generic name of zsles
of elevation, thus dispelling the opinion which long regarded the former as the
relics of a submerged continent.

Scarcely had he returned from the Canaries (about 1819) when some inquiry
led him to the Hebrides, whose basalts formed the object of his visit, and thus
the giant’s causeway became the route which reconducted him to Germany.
There, a new problem hurries him to Paris; and though it is the midst of win-
ter, and a bruised arm, the result of his precipitation, threateus to detain him,
he takes with him a young relative, and this time travels post, for his impa-
tience isextreme. “If,” said he, “ Humboldt should have quitted Paris, the
great city would seem a desert to me.’’ He arrives, however, in season, and
the two friends meet; but how is time to be found for long conversations ? All
the saloons are emulous of Humboldt’s presence. ‘The interviews, however,
take place regularly, only they commence at midnight and do not terminate
until morning.

This strain of scientific excitement, added to the cold, renders Von Buch
really ill. M.-d’Arnim,* his young relative, hazards some expressions of
blame. ‘True, it is my own fault,” replies the culprit, “the fire of the chim-
ney near which we were talking had gone out and I felt chilled; but by making
amovement to rekindle it I should have perhaps hastened Humboldt’s depar-
ture. I preferred suffermg to being deprived of his conversation, and am
well content, for I have gained much by it.”

Hitherto Von Buch had presented his leading idea of the upheaval of
mountains with the reserve distinctive of the conscientious though bold in-
quirer. In 1822, after a new exploration of the south Tyrol, he shows him-
self more decided, and in a letter to Humboldt, on that country, has given us his
ultimate determination in regard to those great and hazardous questions. Here
he pronounces, with an authority which no one as yet had acquired on this
subject, that all the projecting masses on our globe owe their present position
to an actual upheaval.t In this he finds an explanation of the fact, till then
inexplicable, that marine shells occur on the summits of the highest mountains ;
not that the seas have risen to those summits,t it is the mountains which have
been raised from the bottom of the seas. Never had a graver difficulty, nor
one which longer resisted the efforts of ingenious minds, been solved in a sim-

*T am indebted to M. d’Arnim for most of the private traits of character given in this nar-
rative.

+ ‘* The pyroxenic porphyries of Fassa owe their actual position toan upheaval. But we
must carefully observe that it is not the particular elevation of a rock which is in question,
but the lifting up of the whole mass of mountains, and consequently of the entire country.”—
Letter to M, de Humboldt, &c. ‘‘It is now many years since I entertained a doubt that the
whole chain of the Alps—at least the calcareous Alps—owed its elevation to the pyroxenic for-
mation. ‘This formation breaks the strata which oppose its egress. It pierces or upheaves
first the red porphyries, then the sandstones, then the calcareous strata.”—Jbid.

¢ ‘* Reflecting on the effects of these upheavals, we shall be less surprised at meeting
with petritactions of anomis in the sandstones and calcareous strata at the height of nearly
8,000 feet above the Sasso di Val Fredda. These same petrifactions, which are found at
5,406 feet above the passage of the Caressa, 3,800 feet above Seiss, 2,600 feet above Saint
Paul and Caltern, were, perhaps, before the catastrophe of the upheaval, situated lower than
the level of the seas.””—Letter to M. de Humboldi.

MEMOIR OF LEOPOLD VON BUCH. . 369

pler manner. By reversing the fact and presenting it as it really occurred, the
explanation at once presents itself and changes the face of the science.

With Von Buch it was inevitable that one discovery should lead to others.
Thus, a first view reveals to him the upheaval of mountains and that of conti-
nents ; a second, the mechanism of the formation of volcanoes ; a third, the re-
lation which connects the displacement of seas with the elevation of mountains.
One of his most prolific views, that of the discordance of rocks, disclosed to
our distinguished colleague, M. Elie de Beaumont, (a geologist who, by his own
labors, has united the researches of Cuvier with those of Yon Buch, )* the first
germ of his learned theory of the relative age of mountains. We owe still an-
other highly ingenious and novel conception to Von Buch. His explanation
of the formation of dolomite,t or, more generally, of the alteration produced on
deposited and sedimentary rocks by. the incandescent rocks of elevation which
have traversed them, though still subject to some difficulties,t must alw ays be
looked upon as an indication of a high order, and as having marked out for
modern geology one of its most important objects, the study of the secondary
action of fire on the envelope of the globe.

After so many brilliant labors, the smiling banks of the Spree, with the re-
turn of every autumn, continued to recall this eminent and indefatigable man
to the quiet retreat which he had chosen. There, a simplicity, the more charm-
ing as it was wholly voluntary, presided over the economy of his daily life.

t ‘Cuvier has shown that the surface of the globe has undergone a succession of sudden
and violent revolutions. Leopold von Bueh has indicated definite and marked differences
between the several systems of mountains which diversify the surface of Europe. I attempt
nothing but to bring into relation these two orders of ideas.” —Elie de Beaumont: Recherches
sur quelques-unes des revolutions de la surface du globe.

t By the formation of dolomite, Von Buch designs more precisely the change of calca-
reous shell-bearing stone into calcareous magnesian stone.

‘* How-comes it that the magnesia can pierce, traverse, change the nature of the calcareous
beds, which are many thousand feet in height, to make of them a rock uniform in its whole
extent? It is a question which I have proposed to myself in all my excursions in the neigh-
borhood of the valley of Fassa, without finding a solution. The calcareous stone does not
contain magnesia. It comes, then, from another quarter, and it is quite natural to believe
that it is the pyroxene which furnishes it, since magnesia is one of the constituent parts of
this substance. I think I have discovered, in the environs of Trento, the process of nature in
this operation, and this process has appeared to me so evident that at the instant of the ob-
servation I experienced the most lively satisfaction which I have ever felt in my excursions
across the Alps.””—Lettre @ M. de Humboldt, &c.

‘* We can easily conceive that a mountain rent and fissured must lose every appearance of
beds; that thousands of channels are opened for the magnesia to introduce itself and com-
bine with the calcareous rock ; that by little and little all the mass must change into rhombo-
hedrons ; and it is in this way that compact beds, filled with shells, may change into a mass
uniform, white, granular, and saccharoidal, without a vestige of organized bodies or any hor-
izontal fissures whatever ”’—IJbid.

‘This splitting recalls the phenomena which may be daily observed in limestone furnaces
when the fire is withdrawn from them. In going trom Cortina, in the valley of Ampezzo, to
Toblach, in the Pusterthal, one is surrounded, during the whole transit, by peaks of dolo-
mite. The aspect of these places is so singular that we might think ourselves transported
into the midst of an immense furnace. The fragments of dolomite are traversed by immense
clefts; they appear rough to the touch, like all substances exposed to the fire. One is
tempted to attribute these extraordinary effects to the high temperature which the pyroxenie
porphyry had acquired when it penetrated through the inferior strata, and lifted up the dolo-
mite in the form of columns, pyramids, and towers. I am persuaded that this same pyrox-
enic rock has converted the compact masses into granular masses, that it has caused the dis-
appearance of every vestige of stratification and of organized bodies, and that it has given
rise to those fissures which are strewn with crystals. We can no longer doubt that it is the
compact limestone, which is constantly found under the dolomite and above the sandstone,
that has been whitened, fissured, and transformed into a granulated rock.”—Letire sur la
dolomie du Tyrol d@ M. Alois de Pfaundler.

t On these difficulties, see the important and ingenious labors of MM. Haidinger and
Morlot. [The subject will be found also elaborately discussed in the article on the meta-
morphism and crystallization of rocks, by Mr. Daubrée, translated for and published in the
Smithsonian report. for 1861. ]

24 8

370 MEMOIR OF LEOPOLD VON BUCH.

The necessity of peaceful labor, and, therefore, of silence, had induced him to
limit his personal retinue to unity, and when age had relaxed the activity of
this one faithful domestic, Von Buch, like Leibnitz, had his food brought to him
from without. Often his door was opened by himself. If the stranger was
one whose presence seemed likely to be importunate, to the question, “Is M.
Von Buch at home ?”’ he would quietly reply, “ No ;” and, closing the door, re-
turn to his occupations. ‘The young princes of the royal family were some-
times among those who hazarded the experiment, and their admission was due
not so much to their rank as to the affectionate relations which existed between
Von Buch and his sovereign, who, among other marks of his favor, had made
him one of his chamberlains—a chamberlain, it must be confessed, of very
slender assiduity in his office. If the interruption was occasioned by the ar-
rival of a savant, on the very threshold, and without waiting to bid good day,
he would encounter the visitor with some such question as this: “Is the sem-
bi-lobate divided ammonite found also in Thuringia ?”’

An unappeasable curiosity had directed our geologists’ inquiries to that part
also of the terrestrial envelope which is traceable to the action of water, and
which paleontology had recently occupied in its search for the remains of ex-
tinct races.

Since life appeared on the globe, it has undergone many vicissitudes and
clothed itseif with many forms ; Jlifferent species have succeeded one another,
and as each has surrendered its Spoils to the cotemporary strata, these relics
determine the relative age of the deposits, and the history of life serves to il-
lustrate and complete the history of the globe. Von Buch, after Buffon, aptly
compares fossil shells to medals, and adds, in terms of his own, that these
medals also have their /anguage. In a series of memoirs on the ammonites, the
tercbraiula, the productus, &c., he has taught us the means of interpreting that
language; the new and difficult art of distinguishing with certainty the species
which identify the several strata, by characters on which he had bestowed the
most earnest and profound study. Nor were his efforts for restoring the ancient
annals of the world limited to shells; to fossil botany he brought the same aid,
a precise determination of characters, which he had conferred on fossil geology,
so that the expressive epithet which he gave to certain fossil shells and leaves,
calling them guzding ones (conductrices), might well be transferred to himself.
He has truly proved, in these delicate investigations, a guide to other geolo-
gists.

But to be an intellectual guide did not alone suffice for this good and emi-
nent man. Wherever he could discover young persons whose success seemed
only trammelled by the rigors of fortune, he was sure to interpose ; and, as if to
compensate for the modesty of his own wants, he acted on those occasions with
a regal munificence. Such instances were numerous and were seldom made
public.

‘Towards a vessel ready to sail, a young savant was one day directing his
steps; his baggage was light, though he had divested himself of his patri-
mony to procure the means of pursuing his explorations in America. By the
way side a stranger is waiting for him, and says: ‘A friend, impelled by a de-
sire to promote the progress ‘of science, begs you to employ this in its service;’
he places a purse in the hands of the traveller, and disappears. Being once
at Bonn, Von Buch received a visit from a youthful professor of that univer-
sity, who desired letters of recommendation, as he was about to join a scien-
tific expedition. Return to-morrow, replied the distinguished savant. ‘The
interval is employed in seeking information. At the hour prescribed, the young

man presents himself, the letters are ready, they converse ; Von Buch becomes
animated, affectionate, gives advice, and finally says to the visitor at taking
leave : : “IT have a service to ask of you.” “ Compliance will give me plea-
sure,” is the prompt response. ‘‘ Yes, yes,” cries Von Buch, “they all say the

MEMOIR OF LEOPOLD VON BUCH. StL

same thing, and afterwards complain that I have charged them with commis-
sions which annoy them.” ‘The young man protests, cannot conceive how he
should be suspected of insincerity and ingratitude. “ Very well,” replies the
adroit interlocutor, ‘give me your word of honor that you will not even answer
me after receiving my commission.’ ‘The other pledges himself. ‘“« Now that .
I have your word,” resumes Von Buch, “here are 2,000 dollars which you are
to make use of in your travels.” As the injunction did not extend to silence,
the recipient felt constrained afterwards to share the secret with others besides
his benefactor. A young painter, tormented alike by the fever of art and the
anguish of destitution, was languishing at Rome; there was nothing which
singled him out but his talent and his misery. Von Buch charges one of the
embassies with the remission of a considerable sum; and that the artist may be
restrained by delicacy from attempting to penetrate the mystery, he is to be
told that it is a family restitution of an ancient date.

As it was one of the chief pleasures of Von Buch’s life to restore hope to
the unfortunate, so it peculiarly suited his character to act as a peace-maker
between the learned when divided in opinion; before all things, however, it
was indispensable that science, his sublime mistress, should be treated with the
most exact respect. Just and gencrous in his appreciation of men, he was al-
ways zealous in setting forth the merit of the labors of his cotemporaries. A
sure and constant friend, though blunt, eccentric, and at times impatient, he
was ever ready, if umbrage were taken, to make the advances necessary for con-
ciliation. Among intimates he was fond of recounting the ludicrous mistakes
which had been occasioned, during his travels, by the grotesque appearance
under which he presented himself.

He loved socicty, but not what is called the great world. Those who had
seen him at court, whither his office, as well as the propricties of his station in
life, sometimes led him, might have thought him drawn thither by his tastes,
but his resort even there was to the circles in which intelligence supplied the
attraction. In these, the graces of language springing from an active and full
mind, re-enforced by a surprising memory, gave to his conversation when he
was in the vein a peculiar charm. Polished in the company of females, he
knew how to appreciate those who in the courteous collisions of which our
saloons are the lists, and which we call conversation, furnish by their sprightly
sallies often the best, but certainly the most graceful contingent. This admi-
ration, however, never trenched upon the liberty which he had consecrated to
science. Von Buch never married, but, in return, the family affections exer-
cised over him the blandest and most potent influence, and his love for the
young, towards whom he could find indulgence for everything but self-suf-
ficiency, prompted many of the actions of his life.

When far advanced in age, he still quitted his domestic roof with the first
breath of spring. “I shall travel,” was his simple announcement, and a walk
would conduct him from Berlin to Dresden, to the surprise of his more seden-
tary associates in the latter place; thence his course would be prolonged as far
as Bohemia or Switzerland. It was when an old man that he sealed the moun-
tain ranges of Greece, secking among the extinct populations only those which
ally themselves with the real world, and finding more attraction and instruc-
tion in the chronology of a shell than in all the brilliant fictions which ani-
mated Parnassus and Hymettus.

In 1850, a German university having summoned naturalists to a congress
intended to celebrate the memory of Werner, Von Buch was present, and of
course became the centre of all regards, a tribute which, with an affectionate
simplicity, he studiously referred to his early master. “ As for myself,” he
pleasantly said, in allusion to the only official title which he had ever adopted,
“ Tam nothing more than the oldest of the royal pupils of the kingdom of

°
Prussia.”” His return from this reunion conducted him through the country of

an MEMOIR OF LEOPOLD VON BUCH.

his birth, and the view of those fair scenes which he animated with the memo-
ries of his youth, plunged him into reverie. It was observed that he passed
a long night in deep meditation, in which he seemed to address to the places
he was regretfully leaving a touching and silent adieu.

He came once more, however, to visit France, whose genius he loved, and to
sit in that Academy to which he prided himself in belonging. He left Paris
only in the last days of 1852, and peacefully breathed his last in the spring of
1853.

Von Buch, who had qualified himself for the direct contemplation of nature
by always and everywhere pursuing her indications, has left us an example of
one of the noblest of scientific careers. He had the happiness to consecrate a
long life and a penetrating genius to the profound and unwearied study of one
of the highest questions of natural philosophy. Descartes had suspected
the igneous origin of the globe ;* Leibnitz had inferred its incandescencet
from the traces everywhere apparent of a vast pristine fusion; Buffont had
demonstrated the existence of the primitive fire, still subsisting, and more and
more concentrated in the interior of the earth; Dolomieu§ finally had pro-
nounced before this Academy the words adopted by Lagrange:|| ‘ ‘This
elobe, at first incandescent and fluid throughout its whole mass, is still so in
its interior, and has nothing solid but its crust ;’’ but no one more contributed
than Von Buch to prepare the vast and sublime generalization which dares to
place in this profound and central fire, of which, however, he himself has
nowhere pronounced the name or fully admitted the idea, the first and sole,
the potent and terrible cause of all the revolutions of our globe.

The author thinks it his duty to acknowledge the assistance he has derived,
in preparing the above memoir, from the eloquent and learned Nofices of the
ereat geologist, published in Germany, by MM. Geinitz, professor of the Poly-
technic School of Dresden ; Cotta, professor of the School of Mines of Frey-
berg ; Dechen, director of mines at Bonn; Noggerath, professor at the Uni-
versity of Bonn, and a fifth, anonymous, pronounced April 6, 1853, before the
Geological Society of Germany.

* “Tet us suppose that this earth on which we reside has been once a star composed of
matter of the first element absolutely pure, so that it differed in nothing from the sun except
in being smaller.”—(Descartes: Les Principes de la Philosophie, LV part.)

+ ‘It seems that this globe has been once on fire, and that the rocks which form the
base of this crust of the earth are scoria remaining from a vast fusion.’’—(Leibnitz : Proto-

@a, &e.
zi t oe internal heat of the globe, still actually subsisting, proves to us that the ancient
fire which the earth has sustained is not yet by any means entirely extinct; the surface is more
cooled down than the interior. Conclusive and repeated experiments assure us that the entire
mass of the globe has an inherent heat, altogether independent of that of the sun. This heat
we recognize in a palpable manner as soon as we penetrate into the interior of the earth, and
it augments in proportion as we descend.””—(Bufton: Epoques de la Nature.)

§ ‘ While insisting on facts which seem to me of great importance, and again repeating
that the unknown cause which produces the fluidity of lavas appears to me to exist under
the consolidated envelope of the globe, I should add that it is not without design that I em-
ploy the expression consolidated envelope ; for if I cannot doubt that our globe has once been
fluid, there is nothing to prove to me that there can be anything consolidated about it but a
crust more or less thick; nothing to show that the consolidation, which has been necessarily
progressive, has yet attained the centre of this spheroid. Iregard the general opinion which
ascribes a solid nucleus to our globe as a gratuitous hypothesis, and the opposite hypothesis
appears to me much more probable, since with it we can explain a multitude of important
facts which, without it, are inexplicable.”—(Dolomieu: Rapport fait al Institut national sur
ses voyages de Van V, VI.—Journal de Physique, 1798.)

| ‘*The suffrage of the illustrious Lagrange is of too great weight and too flattering not to
be insisted on when one has had the good fortune to obtain it. It was not without much
timidity and circumspection that I hazarded this hypothesis before my colleagues, when the
celebrated geometer, warmly seconding my opinion, asserted that it was not only highly
tenable, but that to him it appeared the more probable inasmuch as there seemed to be nothing
in direct opposition to it.”—(Dolomieu: Ibid.)

MEMOIR OF LOUIS JACQUES THENARD.

By MF DOURENS.

PERPETUAL SECRETARY OF THE FRENCH ACADEMY OF SCIENCES.

TRANSLATED FOR THE SMITHSONIAN INSTITUTION BY C. A. ALEXANDER.

Alchemy, the offspring of man’s love for the marvellous and proneness to
credulity, and therefore almost as old as the world itself, was introduced into
Europe by the Arabs. It promised riches and health: no wonder it was re-
ceived with general homage. Its immediate object was that mysterious sub-
stance the philosopher’s stone, by means of which it proposed to effect the
transmutation of all metals into gold, to cure all diseases, secure an indefinite
term of life, and open for men an intercourse with spiritual beings. Thousands
of ardent adepts dedicated their lives to this chimera, one of whom has thus
described his fellows: ‘An eccentric, heteroclite, heterogeneous, anomalous sort
of men, possessed of a strange and peculiar taste by which they ingeniously
contrive to lose their health, their money, their time, and their life.” I'rom the
midst of the darkness, however, leaped some vivifying sparks; these indefati-
gable seekers bequeathed us several enduring acquisitions; it is to them we
are indebted for gunpowder, alcohol, the mineral acids and antimony. Roger
Bacon, Arnaud de Villeneuve, Raimond Lully, Valentine, Paracelsus, Van Hel-
mont, Becher, are the representatives of this heroic age of chemistry, which
recognizes them as its authors.

Absurdity long shackled the progress of the new science. Saint Simon
gravely tells us that the Duke of Orleans, “who diligently cultivated chem-
istry, had used all its resources to get a sight of the devil, but without success.”
That elder age of the alchemists, which had failed in supplyirg the means for
getting sight of the devil, had been followed by one which did succeed in
getting sight of the Arabian remedies, an achievement, according to Gui Patin,
of just as little value. “I have made enemies, he complains, of all the Ara-
bian cooks who, with antimony alone, slay more persons than the King of
Sweden has done in Germany.” He describes the physician of Cardinal
Mazarin as one who “piques himself on three things which no wise man ever
did—a knowledge of chemistry, astrology, and the philosopher’s stone; it is not
with such fine secrets as these that maladies are to be cured.” One of these
fine secrets, however, was destined to make its way in the world. Lemery,
arriving at Paris in 1666, attached himself to Glazer, then demonstrator at the
Jardin du Roi, as the best source of experiments and analyses.‘ Unluckily,”’
says Fontenelle, “he found that M. Glazer was a true chemist, full of absurd
ideas, and jealous even of these.’”’ Quitting him, therefore, Lemery entered
himself as master apothecary, inseparable then from the character of chemist,
and opened a course of public lectures. ‘‘ His laboratory,’ Fontenelle tells us,
‘was less an apartment than a cavern, which might have been taken for a magi-
cian’s, lighted as it was only by the glare of furnaces. Yet the resort to it was so
great that the operator could scarcely find room for his exhibitions.” This
course was printed, and as it professed to divulge what was then called the

ote MEMOIR OF LOUIS JACQUES THENARD.

secrets of chemistry, the book sold, adds Fontenelle, “like one of gallantry or
satire.” It is true that, by using intelligible language and precise ideas, Lemery
cleared away much that was mysterious and gave an important impulse to
chemistry. But a science only acquires consistency when known facts are
united by acommon bond. This the German physician, Stahl, attempted to
effect in regard to the great phenomenon of combustion, and his explanation
of that phenomenon, by the disengagement of a principle which he called
phlogiston, held learned Europe in thrall for fifty years.

This system was overthrown by a Frenchman who, though idly charged
with being too much of a financier for a savant, and too much of a savant for
a financier, made his own epoch the great epoch of chemistry. Lavoisier
began with teaching us that air, the medium in which we live, is composed of
two gases, one of which, oxygen, serves for respiration and combustion, while
the other, azote, is unsuitable for those purposes. He showed that an animal
immersed in oxygen breathes therein with more energy than in common air,
but dies if immersed in azote. He demonstrated that combustion can never

take place without oxygen ; that metals, in calcining, increase in weight, and

that they acquire this i inevease because oxygen nite with them. This theory
of combustion, by the decomposition of air and fixation of the oxygen, seemed
to leave nothing wanting when the illustrious chemist further evinced that this
same oxygen was also the principle of acidification.

Nothing could be more simple and satisfactory than this chain of discoveries.
Under the impetus thus given the progress of chemistry became a series of
marvels. France must ever mourn the sacrilege which prematurely terminated
the life of her gifted son, but the interests of chemistry did not languish in the
hands of the Berthollets, the Fourcroys, the Monges. Illustrated every day
by some new application, this science rapidly advanced toa popularity which
none of its sisters could emulate.

The story is told us that a boyish herdsman one day exclaimed, “Were I
Emperor, I would tend my cows on horseback.” “And I,” rejoined his com-
rade, “would eat meat three times a week.” «For my part,” cried the third
and youngest, “If such a thing should happen to me, I would be paid thirty
farthings a day, that I might give twenty of them to my mother.’ Animated
by some of these primitive and better inspirations, which find no echo in our
large cities, three vigorous lads of Champagne were traversing, on a fine morn-
ing in spring, one or the great routes which lead to the capital of France.
With swelling hearts and light purses they had quitted the paternal roof and
the village of La Louptiere, near Nogent sur Seine, and had turned their faces
towards ‘Paris: not with a view to mnie their fortunes there, but from an ambi-
tion to add something to the stock of knowledge which they had gathered from
the lessons of his reverence, the curate, and father Bardin, then the oracle of
the department. One of the three looked forward to nothing less than being
physician of his parish; the others proposed to occupy the same field, as apothe-
caries; the most enterprising of the three thought of adding something to the
profits of the laboratory by a small trade in groceries. What justified the
more avaricious projects of the latter was ‘hen circumstance that his parents,
honest tillers of the soil, had lost some moderate resource through the undis-
tinguishing violence of the revolution, and were burdened besides with the
support of five other children. The one now departing, moreover, had been
ever the ambitious hope of his mother; what more natural than that he should
form plans for her gratification.

As our young adventurers neared the great city, the centre of so many illu-
sions, it occurr aT to the most cireumspect of the party that it would not be
amiss to scrutinize the resources of their budget. Scrupulously told, the con-
tents could by no dexterity of computation be ‘br ought to authorize an outlay of
more than sixteen sols (eightpence) a day for each of them. This considera

MEMOIR OF LOUIS JACQUES THENARD. B72

tion determined them to direct their steps to the furthest recesses of the Latin
Quarter, and even there it was only in the highest story of one of the build-
ings that they found the refuge of a common chamber. Under the same roof
there happened to be then domiciled a family of those hardy natives of
Auvergne, who, that they may some day possess a rood or two of land and be
enabled to die among their mountains, distribute for thirty years water and
charcoal among the inhabitants of the capital. With the maternal head of this
family the young financier, whose thoughtful foresight has been already sig-
nalized, opened negotiations for himself and his comrades, and although the
difficulties of the situation were avowed with the ingenuousness of seventeen,
and the worthy dame could not but feel the risk she incurred in undertaking to
provide for the demands of three young stomachs on such scanty resources;
although it was now the epoch of “ninety-four,” and she a mother, or rather
perhaps for that very reason, she agreed to receive them as boarders. Thus
were physical needs provided for ;
° Food and a shelter; who could ask for more?

It remains to say that the conductor of this negotiation, one of the most
critical of his life, who thereby secured himself a footing in Paris, was Louis
Jacques Thenard, born May 4, 1777. Once or twice in the beginning of this
engagement it happened to him to be too late for the culinary arrangements of
mother Bateau. ‘The trying abstinence which such a lapse of attention imposed
left its lesson. ‘I acquired from it,”’ he said in after life, “a habit of punctu-
ality from which I have never deviated, and which adds to the claims of that
excellent woman to my grateful remembrance.”’

Two eminent men were then engaged in teaching chemistry. Fourcroy, by
the clearness of his intellect and a ready and learned method, had achieved a
success which secured him universal reputation. Vauquelin, less brilliant but
more experimentative, had amassed by incessant labor the materials with which
he has enriched science. Our young champagnard, all eyes and ears, lost not
one of their lessons; he listened and still listened; at length conscientious self-
examination satisfied him that he comprehended nothing. At this mortifying
discovery, one which the incapable never make, he arrived on a sincere scrutiny
of the obstacle at the conclusion, that in a science not purely speculative it is
necessary to begin by a practical initiation. Vauquelin, who was then poor,
gave admission into his laboratory to such of his scholars as could pay a fee of
twenty francs a month, but with such a condition Thenard had no means of
complying. Yet here alone could he see any resource, and therefore, taking
courage, he presented himself before the professor, candidly disclosed to him at
once his penury and his inclination to labor, and entreated to be received, if
even on the terms of a domestic assistant. Wauquelin had, however reluctantly,
before discarded such offers; the analogy of his own situation at one period did
not prevent him from beginning to frame a refusal, when happily the interposing
voices of his own sisters, who had entered at the moment and were touched by
the mortification, the intelligence and even, through sympathy, by the provin-
cial accent of the young candidate, came to his succor. “Ah, do not send
him away; observe how modest, how docile he is; he would not only be useful
in the laboratory, but would mind our pot of soup, which most of your dawd-
lers suffer to spoil by overboiling.” ‘Thanks to this lesson in practical chemistry,
‘Thenard was accepted. ‘I have never been so ungrateful,” he used afterwards
to say, “as to forget that a pot which is allowed to boil can make but indifferent
soup.” His rapid intelligence and accommodating nature soon made him a
favorite with the youth who frequented the laboratory and procured him at the
same time the means of extending the circle of his studies and developing his
singular dexterity.

‘Three years now passed by without bringing any marked alleviation of his

376 MEMOIR OF LOUIS JACQUES THENARD.

condition, but without any abatement on his part of heart or hope. Vauquelin
at length procured him a tutorship in an institution, and Thenard, though look-
ing but remotely to the exigencies of a lecturer’s chair, felt the necessity of
reforming an accent and gesture which reflected the impressions of his native
province. For this purpose, as well as from a very decided taste, he attended
the theatre as often as his stomach would compromise for an abstinence suth-
ciently long to justify an expenditure of thirty sols. One morning Vauquelin
said to him; “I am summoned to Rouen; my course has commenced; you
must occupy my place.”’ Unavoidable deficiencies could not but make them-
selves perceptible, at the first lecture, to the new professor as well as to his
audience, but each succeeding one was marked by so much improvement that,
at the fifth, Thenard ventured to cast his eye over the throng and discovered
Vauquelin and Fourcroy, in a corner, smiling at his efforts. “At the sight he
precipitately abdicated the chair. But from that time those eminent men
labored in concert for his advancement, and succeeded in securing him an assist-
ant professorship at the Polytechnic School. ‘The carliest accession of a little
ease and leisure was but a signal to Thenard for the institution of original
researches. Beginning with 1799, when his first Memoir was presented to the
Academy, that body has known him, for more than half a century, to lay before
it, several times in each year, the results of inquiries which have formed the
basis of striking improvements in science, the arts, and industry. Summoned,
one day, unexpectedly and not a little surprised, into the presence of the min-
ister of the interior, the latter said to him: “There is a deficiency in the supply
of ultramarine blue, which is, besides, always scarce and very dear, and Sévres
stands in need of a material which can resist an intense fire. Here are fifteen
hundred francs; go and find me a blue which will answer the required condi-
tions.”’ WiionanaK began to stammer an excuse. “I have no time to lose,’’ said
Chaptal, the minister in question, in a petulant tone. “Go and bring me my
blue as soon as possible.” In a month from that time the rich tints of the
beautiful fabrics of Sévres bore witness to the success of the chemist.

In 1803, Thenard had shown that the supposed zoonic acid was but an
impure acetous acid, and although Berthollet, then in the zenith of his reputa-
tion, was the discoverer of this acid, the circumstance produced no change in
the generous appreciation which the latter always manifested for his young
competitor. Nor was this the only occasion on which Thenard, firm in the
expression of his own convictions, was called upon to contravene so imposing
an authority. When occupied with the oxidation of metals, he unhesitatingly
maintained the idea of oxides in fixed proportions in opposition to Berthollet,
who denied it.

Thenard devoted much attention to organic chemistry, and although later
inquirers have advanced beyond him, there still remains to his share the merit
of having clearly conceived and indicated the relations which connect chemistry
with physiology. This science of life rests on an art in which chemistry is
pre-eminent, on the high and delicate art of analysis. It was this art which,
in its higher and more subtle applications, Condillae first introduced into phil-
osophy, and Lavoisier tells us that he himself derived it from that acute thinker.

In 1807 appeared researches of great interest on ethers. ‘These, it was
known, are formed by distilling certain acids with alcohol, and this was all that
was known. Thenard announced several new ethers; and, yet more, laid a
foundation for the theory of these agents, which have already revealed to us
some of their surprising effects on life, and doubtless hold in reserve others
more surprising still.

During this period, of engrossing application, Thenard was, early one morn-
ing, surprised by a visit on V auguelin. ‘Up, in all haste,”’ cried the visitor,
“and apparel yourself handsomely.”’ Thenard, scarcely awake, asks an explana-
tion. “The law respecting pluralities forces me to resign my chair at the Col-

MEMOIR OF LOUIS JACQUES THENARD. i

’

lege of France, and I require you to go at once and apply for it.” Thenard
feels a delicacy. ‘Come, come,” rejoins the professor; “be quick; I have
taken the cabriolet by the hour and you ruin me with these delays.” The
necessary visits being made, Thenard readily secured the position which con-
duced so much in the end to his extraordinary popularity. The students
seemed to attach themselves with peculiar enthusiasm to one raised by toil from
their own ranks and wholly unchanged by his elevation. Vauquelin, who con-
tinued to watch over his interests, and who greatly admired in Foureroy the
charms of delivery which he himself neglected, would fain have invested his
favorite pupil with this additional attraction, and Thenard readily lent himself
to the attempt. It was perhaps the only experiment in which he ever failed.
In vain did he seek for models in society, counsels from his friends, instructions
from our great actors, Molé and T'alma; the cham ypagnard was destined to bear
to the end the original impress, somewhat rough perhaps, but thoroughly French,
which definitely consigned him to a type well recognized and not a little vaunted
by our national self-esteem,

A few years only separated Thenard from the period when foreign invasion
had made it necessary for France to improvise nearly all the resources incident
to war. ‘To this end, none had contributed more efficiently than Monge and
Berthollet, who afterwards accompanied Napoleon to Egypt, and were often
consulted by him when subsequent successes had placed him at the summit
of power. ‘Tell me,’ he said one day to Laplace, “why it is that I see at
present so little of Berthollet?’ ‘My friend,” replied Laplace, “has become
embarrassed through his undertakings for the advancement of industry, and is
chagrined that it should be so.” ‘Tell him to come and see me,” said the
Emperor. Soon after, seeing his old Egyptian at the extremity of the saloon,
he goes directly to him and extends his hand. “ Berthollet, you are unhappy,
and you do your friends the injustice of not confiding your cares to them:
name the sum you require, and think no longer of anything but your researches.”
Berthollet was then initiating in these researches a young man whose zeal and
intelligence rendered him an invaluable assistant in the laboratory. Gay
Lussac, in his earliest memoirs, gave evidence of that precision of thought and
accuracy of¢judgment to which in the sequel chemistry has been indebted for
so many important services. An analogy of position soon induced between
him and Thenard relations of confidence and co-operation, while both were so
fortunate as to enjoy the advantages of the scientific retreat which Berthollet
had created for himself at Arcueil, and which Laplace often animated by his
presence and patronage.

About this period a great sensation was produced in the scientific world.
Berzelius had just revealed the power of decomposition exerted by the voltaic
pile upon compound bodies. Davy, availing himself of more powerful appa-
ratus, had succeeded in decomposing the two fixed alkalies, which till then had
been considered simple bodies: in potash and soda he found, united with oxygetl,
two metals to which he gave the names of potassium and sodium. He after-
wards undertook the analysis of the alkaline earths, each of which afforded a
peculiar metal, while in all, oxygen presented itself as a common principle.
Proceeding still further, he disclosed, in a paper full of original views, some
of the profound relations which connect chemical with electric forces, affinities
with electricity. With generous enthusiasm, the Institute of France awarded
to this paper the grand prize founded for the progress of galvanism; and
though war was raging between the two countries, the English savant was
invited to come and receive it in person. This was an act of justice nobly
accorded.

“Will you tolerate this triumph of the English ?”’ impatiently demanded

Napoleon of Berthollet. A gigantic pile was forthwith constructed by the
Kmperor’s order, and confided to Thenard and Gay Lussac, who soon after

378, MEMOIR OF LOUIS JACQUES THENARD.

were able to announce to the Academy that by means of the ordinary affinities
they had succeeded in obtaining new substances more abundantly than by the
pile. By employing potassium and sodium, they effected the isolation of a new
and simple substance, which they named boron.

Davy recognized the superiority of the chemical method for the extraction
of metals; but he claimed this boron as an element which had come to light
through his own investigations. This Thenard and Gay Lussac would by no
means concede, and they were right; but they maintained at the same time
that sodium and potassium, so far from being simple bodies, were combinations
of alkalies with hydrogen, or hydrurets. Their English rival justly answered
that, if they adhered to this theory, it would follow of course that their simple
principle of boron was but a hydruret of boric acid—an argument which re-
mained unanswered. ‘This, however, was the commencement of a discussion
which, with profit to science and credit to both countries, continued for not less
than five years, and which marks the epoch at which the basis of existing ideas
respecting simple bodies was definitely fixed.

In one of the memoirs in which they rendered an account of the different
aspects of their controversy with the English savant, Thenard.and Gay Lussae
had said: “The conjecture is not inadmissible that oxygenated muriatic acid
is a simple body.”? It was not without having first tested this acid with potas-
sium, and strenuously sought to extort some evidence of oxygen, that they gave
expression to such an opinion. For, if oxygenated muriatic acid were ad-
mitted to be a simple body, a new principle of acidification would be disclosed,
and “a serious breach be thus made in the theory of Lavoisier. Recoiling
from this consequence, and restrained moreover by the immovable opposition
of Berthollet, they hesitated to pronounce more decidedly. Hence the recog-
nition which they evaded passed to the credit of England. Davy admitted
the oxygenated muriatic acid as a simple substance, giving it the name of
chlorine or chlorium, but at the same time he generously resigned to his two
rivals the first indication of the new principle. Thus the grand theory of
Lavoisier was subjected to modification, though without forfeiting its title ta be
considered one of the noblest contributions of French genius to science.

The two friends, whose resources and reputation had been constahtly increas-
ing with their labors, had, during this whole controversy, been so completely
identified in effort and responsibility, that the learned abroad were disposed to
confound them in a single individuality ; and indeed the part borne by each
remains to this day undetermined. When, in 1809, a course of instruction was
opened at the Sorbonne, both were called to participate. Here Thenard pro-
posed to conduct an elementary course, without discontinuing, however, his more
abstruse labors at the College of France. So great was the concourse of pupils
that space for accommodation was often deficient, and many who had waited
long were forced to retire. This suggested to Thenard the propriety of pub-
lishing his lectures. They appeared accordingly in four volumes, the first
edition in 1813, the sixth in 1836, each edition costing much labor, as the author
continued to intercalate the discoveries and doctrines of successive periods.
This work maintained an exclusive ascendency in the schools for more than a
quarter of a century, so that it may be said that almost all Europe has learned
chemistry of Thenard, and doubtless most of the great chemists of the present
day, French or foreign, would take pleasure in acknowledging their obligations
to his clear and comprehensive method.

When the Institute lost Fourcroy, numerous competitors disputed with
Thenard the honor of succeeding him. His friend Gay Lussac had the satis-
faction of completing, by his first vote, the unanimity of voices with which
his comrade was called to a chair. On this occasion the first impulse of The-
nard was one which sprang from his heart. “When I once -felt assured of
success,” he said, “I immediately set out for Louptiére, full of the joy which

MEMOIR OF LOUIS JACQUES THENARD. 379

I should communicate to my mother. To crown my good fortune, I carried
with me a book which she had asked me for: The Imitation of Jesus Christ,
in large letters, such as she could read without spectacles. When this copy,
so rarely to be met with, fell into my hands, I had regarded it as the happiest
of my discoveries.” At the maternal fireside, the simple habits of his child-
hood were resumed and old associations cordially refreshed. Here he again
listened to the tender counsels of his mother, who, at the moment of parting,
said to him: “It is now time for you to marry.”

This admonition fell on no unwilling ears. From the time when he first
received ithe patronage of Vauquelin, Thenard had formed the acquaintance
of a young chemist, named Humblot, to whom birth and fortune had
opened a path as smooth as his own was rugged. In order to sustain the
courage of Thenard, Humblot had often cited to him the instance of his own
father-in-law, who, at first simply a laborer in a convent garden, had contrived
to evince his talent as a painter, and by the opportune development of other
talents in the service of his country during the Revolution, had achieved for
himself both distinction and fortune; so that it was said of him by a great
man, whose confidence he had won: “Conté is capable of creating the arts
of France in the midst of the deserts of Arabia.” Received into the intimacy
of this family, Thenard, whose origin and mediocrity of fortune were well
known to them, met with warm sympathy in all his successes ; yet was it left
to the sagacity of Madame Humblot to divine, which as » daughter of Conté
she was well qualified to do, that he was silently waiting for some still greater
success in order to acquire the boldness to ask for her daughter—whom Thenard
confessed to be for him only too fair and too rich. This obstacle not proving
insurmountable, our savant married; and as he was a man who ordered affairs
with judgment, and knew how to enter into the details of practical life, he
began from that time to build up the large fortune in which were blended the
results of his labor, his alliance, and his skilful management.

The constantly increasing success of his lectures had become, with Thenard,
the most sensitive test of his self-love. At each of them he seemed to put
forth all the ardor of a general on the battle-field ; leaving nothing unprovided
for, and making but a limited number of experiments, he required them to be
exact and striking, and to be presented at the precise moment. The slightest
inadvertence or misapprehension on the part of his assistants drew upon them
sharp reproofs, and they must have had a hard time of it but for the prompt
return of good nature and the acknowledgments which followed. “In a lec-
ture-room,” insisted Thenard, “it is the students alone who have a right to
be considered ; professor, assistants, laboratory, ought all to be sacrificed to
them.”. Before an auditory which had witnessed one of his outbursts, he
soothed the not unreasonable susceptibility of him he had maltreated by saying,
«Fourcroy has often done the like to me! It produces promptness of appre-
hension.”’

It was this same promptness of apprehension which supplied Thenard with
one of those penetrating insights which open new horizons to science. The
discovery of oxygenated water is recounted by himself in the following terms:
“Tn 1818 I was delivering my first lecture on the salts at the Sorbonne : ‘in
order that the metals should unite with acids, I was saying it is neces-
sary that they should be oxydized, and that they should be so only toa certain
point; when the quantity of oxygen is too great, the oxide loses a part of its
affinity.’ Asan example I was about to cite the deutoxide of barium, when
the thought suddenly crossed my mind that the experiment had not been
made. As soon as I re-entered the laboratory I called for oxygenated barytes ;
I diluted chlorhydrie acid with ice, adding it in such a manner as to have a
liquid at zero. I hydrogenized the barytes and reduced it to the state of
paste. I then made the mixture; when, to my great surprise, the barytes

380 MEMOIR OF LOUIS JACQUES THENARD,

dissolved without sensible effervescence. So anomalous a fact could not fail
to arrest attention. When I returned for my following lecture, I perceived
small globules attached to the sides of the vessel, like those which are seen in
a glass filled with champagne wine; bubbles of gas were escaping from the
liquid, though quite slowly. I then took a tube closed with the lamp at one
of its extremities, and, pouring in some of the liquid, heated it. The bubbles
were now rapidly disengaged and gas accumulated in the part of the tube
which remained free ; I introduced a match and it kindled—there was oxygen
present. The hour for my lecture had arrived and I went through with it, but
the preoccupation of my mind must have been deplorably apparent.”

Thenard had fallen on the traces of a new fact; at first he was disposed to
believe that he had made the discovery of suroxygenated acids, but he soon
satisfied himself that these acids had no existence. Was it, then, water itself,
simple water, which was oxygenized? The idea had scarcely entered his
mind before it was proved by experiment, and oxygenated water was thus
added to the acquisitions of chemistry.

A new and suggestive fact had been reached by Thenard, the report of
which soon spread through scientific Europe. Foreign chemists came to assist
in the experiments, and the arrival of Berzelius, at this time, in the French
capital, seemed appropriately to welcome the recent discovery. Calling with-
out form on Thenard, the Scandinavian philosopher saw him for the first time ;
yet these eminent men at once recognize each other, and find themselves, as if
in virtue of the law of affinities, converted on the instant into old friends. “TI
come,” said Berzelius, “to gather ideas in the domain of French chemistry,
which you have so much aggrandized and enrichéd. You will, of course, let me
see the oxygenated water.” The conversation turned on Gay Lussac and: his
iodine, the new element which that chemist had so distinctly identified; as
well as on his cyanogen, a compound substance which affects, in-its combina-
tions, all the characters of simple bodies. ‘ We must not forget,” said The-
nard, “the admirable theory of definite proportions which we owe to you, and
which, revealing the immutable laws by which bodies combine, has become the
torch of chemistry.” ‘I admit,” rejoined Berzelius, ‘“ that I have been fortu-
nate. Do you know,” he added, “that your recent labors and those of your
friend have given Davy occasion to say, ‘Thenard and Gay Lussac apart are
stronger than Thenard and Gay Lussac united?’ ”” From this conference 'The-
nard proceeded directly to the Sorbonne, and was conducting his lecture with
his usual facility, when his eyes casually wandered to a corner of the apart-
ment, and he immediately showed signs of discomposure. ‘The audience, in
turn, became uneasy, but Thenard, promptly recovering himself, exclaims:
“Gentlemen, you have a right to know the cause of my embarrassment ;” and,
pointing to a remote part of the amphitheatre, ‘Gentlemen, there is Berzclius.”
At once the crowd rises, and a respectful circle surrounds the illustrious
stranger with long and rapturous applause. Moved by such proofs of enthu-
siasm, and forgetting his usual phlegm, the Swede exclaims, as he is borne
unresistingly to a seat near the chair: “ With such pupils it is impossible to
be other than a good professor.” He afterwards observed to Thenard, “I had
promised myself to verify, in entire secrecy, whether all that fame had taught
me respecting your talents as a professor were exact. I find it even below
your real merit.”

Thenard was now investigating the properties of oxygenated water. One
of them is extremely singular; Berzelius named it the catalytic force. Many
bodies decompose oxygenated water without undergoing any chemical alteration,
without seeming to act otherwise than simply by their presence. The phe-
nomenon, therefore, depends not on the ordinary affinities ; nor yet on electricity,

MEMOIR OF LOUIS JACQUES THENARD. 381

so far at least as was apparent, for the most subtle examination had failed to
discover the least sign of electrical action.*

Is it due, then, to a new force? So Thenard thought and said. The catalytic
foree, he believed, would furnish the theoretical bond of a whole class of facts,
some of which were already known. As the fear of mistake is always associ-
ated, in a practiced mind, with the pleasure of discovery, he called to his aid the
counsels of a friend, a bold and sagacious chemist; and the views of Dulong,
after mature consideration, coinciding with his own, he might with confidence
leave his conclusions to the judgment | of after times.

Thenard, associated in 1810, as professor at the Polytechnic School, with
the eminent men who shed so bright a lustre on that model institution, thoroughly
identified himself with its progress and its benefits; each generation of pupils
which he instructed seemed to afford him a new pledge of the perpetuity of his
fame. In addition to this appointment, he received in 1814 that of member
of the Committee of Consultation for Manufactures; in 1815, he became a
member of the Legion of Honor; in 1821, Dean of the Faculty of Sciences; in
1825, he was created Baron by Charles X. Learning that he was about to
receive this latter distinction, he demanded, with visible emotion, “Why is not
Gay Lussac also named? He deserves it at least as much as I do.”

At the moment he forgot, perhaps, that he had once been a courtier, and a
skilful one: it had been at the promptings, however, of a kind heart. Few
had admired more than he those superb paintings in the cupola of the Pantheon,
in which the pencil of Gros has so admirably imbodied the legends of our
national history. The enthusiasm of his cotemporaries seemed to guarantee to
the artist the admiration of ages to come, when, at the expiration of only a few
months, stains of different shapes and colors made their appearance on the
surface of the nave, and it became evident that, from moisture having pene-
trated the stones, this great work of genius was hastening to decay. The
mortification of Gros eouli be consoled neuer by the public sy mpathy nor the real
concernof the sovereign, who saw with regret the threatened ruin of a monument,
in which a conspicuous place had been allotted to himself. Thenard, between
whom and Gros there existed a sincere friendship, no sooner heard of the
exiastrophe than he commenced in secret a series of experiments, by which he

ewas led to the discovery of a means of rendering the most porous stones imper-

meable to moisture. Once sure of the result, he repaired to the cabinet of the
artist and inquired whether he would repaint the cupola if satisfied that the
colors would stand. ‘Away with you,” roughly replied Gros, “and let me
hear no more about it.” Fourcroy, it will be remembered, had, in the words
of 'Thenard, often done the like to him, so he tranquilly withdrew to his labor-
atory to await the coming of Gros. This was not long deferred; the door
presently opened and the artist inquired, in a voice of anxious emotion, if what
had been spoken of were practicable. That evening Thenard was summoned
to the ‘Tuilleries, his method explained to the satiatncron of the royal personage,
Darecet ‘at his own request was united with him, and he was dismissed with the
promise of a grateful requital.

*See on this subject a very remarkable note of M. Becquerel, Annales de Chimie et de
Physique, t. XXVIII, p. 19, (1825), entitled: ‘‘On the electro-dynamic effects produced
during the decomposition of oxygenated water by different bodies.”” The following is an ex-
tract: ‘‘M. Thenard discovered that the metals, with the exception of iron, tin, antimony,
and tellurium, tend to decompose oxygenated water; that those which are most oxidizable
become oxidized, while those which are not so preserve their metallic lusture. It has been
observed by M. Beequerel, that during the decomposition of oxygenated water by the sponge
of platinum, gold, &c., electrical effects are produced simiar to those which would take place
if those bodies were chemically attacked by the oxygenated water. He inferred that the de-
composition and the chemical action proceed from the same cause; a conclusion which
strongly eR M. Thenard.’’ [See on this subject the prize essay from the Holland
Academy of Sciences, published in the present Smithsonian report. ]

382 MEMOIR OF LOUIS JACQUES THENARD.

That requital our savant was convinced he should never solicit; but who
can count upon anything? One day, at the exit of the students from his lec-
ture, the door is found to be guarded by a force of the police, whose suspicions
involve the whole assemblage. Certain fugitives from a popular tumult
which had just been quelled had found means to make theiz way into the hall,
and confound themselves among the audience. In the clamor which results
the professor is drawn to the spot; the students are at once quict, but the po-
lice refuse to surrender the prisoners. The most that he can obtain is, that
those found with notes shall be liberated as students, and others are enlarged
on satisfactorily answering some scientific interrogatory which he propounds
to them. Fifty, however, of the more unlucky are conducted to prison. At
seeing them led away, the heart of Thenard is touched ; he hastens to the
minister of the interior, but is badly received; to the prefect of police, with no
better success. Suddenly a thought crosses him: “They promised me so much
on account of the cupola!’ Immediately his steps are turned to the 'Tuilleries,
and with difficulty obtaining an audience, he states the case respectfully but
warmly ; they are his cherished pupils, his children ; he will be responsible for
them. ‘Yes,’ replies the king, with a smile, “but those who are ignorant of
chemistry have been put in prison. See my minister, however; the case has
not been provided for.” At midnight the gates of the prison open before
Thenard. ‘Gentlemen,’ he cries, ‘you are at liberty ;” then pausing a mo-
ment on the threshold, he adds, ‘On one condition, however—that you will
learn chemistry.”

Appointed counsellor of the University in 1830, “Thenard,” says M. Girar-
din, “not only rendered to science the great services expected of him, but
proved himself an admirable man of business. Severe against abusesand neg-
ligence, no one lent himself with more lavish facility to all true reforms.
Much as he had to be proud of in this world, I have never known him prouder
and happicr about anything than the right conduct of the state colleges.” For
four years he occupied a seat in the Chamber of Deputies, and as he had ac-
cepted it with reluctance, so he left it without regret, saying, as he repaired to
the scene of rejoicing for the election of his successor, “I am going to assist in
celebrating the restoration of my own liberty.’? His declaration that “he did
not meddle with anything but what he thoroughly understood,” may be held
to have been the rule of his public life. When a member of the higher cham-
ber he moved a revision of the laws of instruction, a reimpression of the works
of Laplace, and the national protection of the widows of learned men ; he gave
also a profound consideration to some of the questions relating to public indus-
try. ‘The spirit of party exercised no dominion over him. Swayed by reason,
he sct no value on administrative parade, preferring to all other authority that
which he exercised as an undoubted master in the domain of science.

During an Academie career of forty-seven years, he constantly yielded a zeal-
ous support to whatever views or undertakings appeared to envelope.a germ
of progress, and there was scarcely one of his colleagues who was not
indebted to him for the suffrage of an applauding voice. It was natural
that he should cherish a profound regard for the Academy where his
fame, his services, and, above all, his habits of conciliation, assured the
highest authority to all his expressions of opinion. In private life he cheer-
fully accepted the obligations of his eminent scientific position, and his house,
open to merit of every description, was the abode of amenity and grace. A
certain vestige of its rustie origin, a simplicity which recalled the character of
our central populations, gave to this amiable household only a new and pecu-
liar charm. In person 'Thenard was large and vigorous, bearing erect a head
covered with a redundance of black hair, with features well marked and
animated by an eye of lively intelligence. It was impossible not to recognize
in him one of those organizations on which nature has lavished all the elements

MEMOIR OF LOUIS JACQUES THENARD. 383

of a complete existence. That attachments, both of a public and private
nature, should gather about one thus constituted, was inevitable ; complaisant
and just, to him all was easy and simple; neither reproach nor ill-will ever
troubled a heart which, more than once, was agitated by the expressions of
grateful acknowledgment.

During his lectures at the Polytechnic School, it happened, on one occasion,
that something essential to the demonstration was wanting. Thenard impa-
tiently calls for it, and while the attendant runs to seck it, lays his hand, as
if to gain time, on a glass, and carries it, without examination, to his lips
Having swallowed two mouthfuls, he replaces it, and with entire self-posses-
sion observes, “Gentlemen, I have poisoned myself; what I have drunk is
corrosive sublimate, and the remedy is the white of eggs; bring me some.”
The students, to whom his first words had conveyed an electric shudder, pre-
cipitate themselves through doors and windows, ransack the neighboring stores
and kitchens, and, as each one brings his contribution, soon an immense heap
of eggs rises before the professor. In the mean time, one of the students has
flown to the Faculty of Medicine, and, interrupting an examination, exclaims,
“ Quick, a physician! Thenard has poisoned himself at the school in delivering
a lecture.” Dupuytren rises, seizes a cabriolet on his passage, and rushes
with breathless haste to the scene of the accident. But, already, thanks to
the albumen, the life of Thenard was saved. Dupuytren, however, insists on
the use of a probe, in order to be sure that none of the corrosive substance is
absorbed by the stomach. An inflammation of the organ is thereby produced,
and Thenard, saved from the poison, is put in danger by the remedy.

During his illness, the students of all the schools manifested the most poig-
nant anxiety ; with affectionate zeal they watched around his house night and
day, in order to avert every possible cause.of disturbance, and listened in un-
easy silence for tidings from the interior. Every morning exact bulletins were
posted in all the principal establishments, without its being known who were
the authors. When Thenatd reappeared in his chair at the Sorbonne, the de-
light manifested was proportionally great. Every one sprang to his fect with-
out seeming to know in what way to express his joy, and the professor for
once confessed himself overwhelmed by a torrent of profound and grateful
emotions.

It might now have seemed that long years of happiness were in reserve for
Thenard, but his fortitude was destined to terrible trials. By a succession of
bereavements he lost almost all which could sooth the decline of life : first, his
mother-indaw, the early friend who had propitiated his happiness; then the
devoted wife who had been its chief dispenser, the latter escaping, by her
sudden removal, the pain of secing their last child expire in the bloom of youth;
a brother, a sister, and a nephew followed. When one only and tenderly be-
loved son remained, the afflicted father exclaimed: “I dare no longer believe
in his existence.”

The counterpoise which he opposed to these often renewed sorrows was the
suggestion of a benign and wise compassion; the foundation of the Soczety of
the friends of Science seemed an inspiration from his memories of the past.
After bequeathing it a considerable legacy, and associating with it all his
friends, Thenard expired June 21, 1857, showing by his latest words that his
solicitude still dwelt upon the cherished “Society.” “I trust,’ he said, “that
I have formed a union which nothing will ever break. I hope that those who
cultivate the sciences, those who are occupied with their application, and even
those who only recognize their value, will continue united for their protection.”
Let the orphan, the widow, the indigent aspirant, salute with grateful accents
the tomb of the excellent man whose last thoughts were for them.

MEMOIR OF M. ISIDORE GEOFFROY SAINT HILAIRE,
BY M. DE 'QUATREFAGES. 4

“From the Bulletin of the Imperial Society of Acclimatation.—Translated for the Smithsonian
Institution. ]

Isidore Geeffroy Saint Hilaire was born the 16th December, 1805; and on
the 10th November, 1861, he sank under an illness whose insidious progress
had set at naught all the efforts of scientific skill and devoted affection, before
he had completed his fifty-sixth year. What this short life had been has
already been related by those whose eloquence was heightened by grief and
friendship, and I have myself said a few words on this subject. What the man
was has thus been declared, but the appreciation of the savant required a little
more development. It is for this reason that I return to the theme. I wish to
sketch, at least, the principal features of that scientific existence which was cut
short at the moment of bearing its finest fruits.

A child of the museum, Isidore Geoffroy took, as we may say, his first steps in
that collection founded by his illustrious father, in those galleries which had
grown, as if by magic, under the united efforts of the Brogniarts, the Cuviers,
the Geoffroys, the Jussieus, the Lamarcks. This daily spectacle would have
inspired even an ordinary mind: judge, then, of its effect on an intelligence of
early thoughtfulness. To this influence add that of family traditions*—the
example and inspiration of a father like Etienne Geoffroy, the lessons of a
mother, whose firm and affectionate heart the most bitter trials have never
shaken, and whose elevated judgment has always been recognized by some of
the greatest minds of our timet—and it will be seen that few men have entered
on their intellectual career under more favorable auspices.

Isidore Geoffroy profited by these gifts of Heaven. He was but nineteen,
when, in 1824, he made his debut as a zoologist, by the publication of a memoir
on a new species of American bat, (Nyctinomus Braziliensis.) He afterwards
returned at different times to this group, which had first been disentangled by
Etienne Geoffroy, and which for that very reason attracted his special attention;
but in 1826, at the age of 21, he laid aside for a time these descriptive labors, to
turn to a subject much less restricted, and which at once revealed the secret of
studies of deep and long continued interest. He published in the Dictionnacre
Classique @ Histoire Naturelle, and soon afterwards in the form of a volume,
General Considerations on the Class of Mammifers. Let us dwell a moment on
this early work, the first in which Isidore Geoffroy presented a grand general
view of facts and ideas. We shall find in it almost all the germs which were
to obtain a rich development in his subsequent works.

* One of the branches of the Geoffroy family gave, in the 18th century, three members to
the Academy of Sciences.

+Madame Geoffroy Saint Hilaire, (Pauline Anois) belongs to a family of the magistracy,
which still adheres to its old traditions. Her father, M. Briere de Mondetour, was successively
Receiyer-général des Economats under Louis XVI, Maire of the 2d arrondissement of Paris,
and deputy of the corps legislatif, under the Empire. In all these situations, he knew how to
merit the esteem of the sovereigns and the respect of the public. In 1804, Mademoiselle
Briere de Mondetour married Etienne Geoffroy, who was already celebrated. She survives
her husband, the twin daughters, and the son, who were the fruit of this union.

~

MEMOIR OF M. ISIDORE GEOFFROY SAINT HILAIRE. 385

In the description of species, our young naturalist had shown that he could
discern and describe with exactness and clearness the most minute characteristic
traits. These qualities, so necessary to the zoologist, are seen in the work of
which we speak. Already he had shown a sort of innate tendeney to ascend
from the details to the whole, to connect isolated facts with general principles.
For example, in speaking of the-caudal development of mammalia, the author
does not content himself with noting the very considerable variations presented
by the number of vertebrae which compose it. He aims to take account of them,
and for this purpose ascends to the phenomenaof their first formation. He reminds
us that in the human embryo, the coceyx, until the end of the second month,
is quite as long as the tail of the dog of similar age. He agrees with M. Serres
in attributing to a retreat about the upper part of the spinal marrow, the arrest
of development which in the human species intercepted the appendage so prom-
inently developed in the dog. He compares these facts with those presented
by the tadpoles of the frog and the toad, and concludes by saying: “Thus the
mammal is metamorphosed like the batrachian, and all the changes which
surprise us in the latter are not even anomalies ; they take place equally in the
mammal, and in man himself; and are the general phenomena of embryogeny.”’
All the:anatomical and descriptive part of the work is executed in the same
spirit. ‘

The hairy coating of mammalia, the variations of color that distinguish races,
the influence of domestication on external characters, the result of the crossing
of species and races, likewise conduct Isidore Geoffroy to general considera-
tions, the greater part of which had escaped his predecessors. In several
passages we see the dawn, more or less advanced, of a great number of ideas
which, ripened by reflection and continued study, served as tlie basis of the
great work of which we shall speak hereafter.

An order of considerations which occupies an important place in this work,
and which we cannot pass without notice, is that which embraces zoological
geography. From the philosophic point of view where the son of Etienne
Geottroy had placed himself at twenty-one, the grandeur and truthfulness of
the conceptions of Buffon on this subject could not escape him. We can see
that he has been deeply impressed with them ; that already he has been seeking
to verify them by ficts; and that if he undertakes the defence of his illus-
trious predecessor, it is with a full knowledge of the subject. This enlight-
ened conviction, which Isidore Geoffroy shared with his father, is evinced in
many of his other writings. Ifthe unjust prejudices inspired by the Linnzan
doctrines, imperfectly understood, have been partly dissipated; if, in our day,
naturalists admit Buffon to be still greater as a savant than as a writer, it is
certainly in great part due to the efforts of these two penetrating minds, so
well formed to comprehend, ‘develop, and inculcate a right appreciation of
what had too long been misunderstood in the genius of their predecessor.

The complete list of the works of Isidore Geoffroy, already published in
this bulletin, renders it unnecessary for us to enumerate here several treatises
of different kinds which succeeded each other rapidly until 1832. We shall
merely point out the tendency, more and more marked in their author, to sub-
ordinate facts of detail to complete views, and to attach himself to general
and philosophic zoology, such as had been comprehended, though from dif-
ferent points of view, by Buffon, Lamarck, and Etienne Geoffroy. These
prevailing ideas were manifested officially, as we may say, in a course of
lectures given at the Athenzum in 1830, which turned entirely on the funda-
mental relations of the animal species among themselves and to the external
world. By this course of lessons, which had no precedent in public instruc-
tion, Isidore Geoffroy began to assume his special place in the phalanx of
those who followed the same banner with himself, and was not long in placing
himself in their foremost rank. Two years later appeared the first volume of

25

386 MEMOIR OF M. ISIDORE GEOFFROY SAINT HILAIRE.

The General and Particular History of the Anomalies of Organization, (1832.)
This time it was no longer a simple memoir, nor a resumé enlightened by new
ideas; but a work sufliciently new in substance and in form to found, at once,
a whole branch of natural science.

It is well known how much the anomalies of organization, designated by .
the name of monstrosities, have, at all times, struck the imagination of the
vulgar and excited the curiosity of the learned. Long regar dod! as prodigtes,*
they became afterwards freaks or errors of nature. They were viewed as
proofs that the laws governing the formation of living beings might suffer
exceptions and infractions. Later, it was understood that physiology was
deeply interested in the study of these supposed abnormal beings. But it had
required the great progress accomplished during the first years of the present
century in anatomy and embryogeny, to demonstrate the extent of the services
which the study of monsters was to render. Etienne Geoffroy had often in-
sisted on this. Resting partly on the doctrines of his predecessors, but espe-
cially strong in his own, he had been the first seriously to take account of the
perfectly natural conditions under which these alterations are produced. Isidore
Geoffroy followed his father in this track. As he says himself, he proposed
to make anomalies better known, to trace their characters, their mode of pro-
duction, their relations, their influence, and thus to lead*to the more perfect
knowledge of the normal order.t

A single fact will show how completely this multiplex aim of the author has
been accomplis shed. These beings, so various, so complex, which had been
considered the product of as many special infractions of general rules, have
conformed to all the exigencies of the classification invented for normal beings.
Isidore Geoffroy has divided the slightest deformities as well as the greatest
monstrosities, those characterized by excessive complication, as well as those
resulting from defective parts, into classes, orders, families, and genera, as had
been done with the mammals or the birds. And this classification has re-
mained unchanged. Some new genera have been added to it, some new species
described, but all have fitted naturally inito the framework so skilfully traced
out by the author between his twenty-sixth and thirtieth year.

The importance of this work was immediately understood. The first vol-
ume, which appeared i in 1832, was a guarantee of those which were to follow.
This consideration decided the Academy, and on the 15th April, 1833, Isidore
Geoffroy, at the age of twenty-seven, took his seat beside his father in the
section of zoology §

The History of Anomalies was completed, and other labors and Es
succeeded. Of these we can notice only a few.

We must first point out the views which Isidore Geoffroy frdggriewly put
forth relative to classification. It is well known what importance has justly
been attached, since the time of Linneus, to,the forms for the arrangement, in
an order determined beforehand, of the numerous beings with which naturalists

*The Greek and Roman Jaws condemned to death every child affected with certain organic
deviations. In the middle ages it was nearly the same; and even in the 17th century Riolan
thought himself very bold, and really was so, in maintaining that they need not be put to
death ; that it was enough to shut them up.

t Analytical Notice of the Zoological, Anatomical and Physiological Labors of M. Isidore
Geoffroy Saint Hilaire, 1853.

} The third volume of the History of Anomalics appeared in 1836.

§ M. Delaunay has preserved the remembrance of an incident which marked this election.
Our confrére has recalled, in happy terms, that Mr. Gay Lussac, president of the session, af‘er
having counted the votes, yielded the chair to Eftenne Geoffroy, then vice-president, in order

to give him the happiness of verifying the triumph of his son himself and proclaiming his
election. M. Delaunay has well depicted the emotion of the Academy in witnessing the
verification of the vote.—(Funcral of M. Isidore Geoffroy: Discourse of M. Delaunay in the
name of the Faculty of Sciences.)

MEMOIR OF M. ISIDORE GEOFFROY SAINT HILAIRE. 387

occupy themselves. We know that these groupings, at first purely methodic,
became.systematic in the hands of Jussieu for vegetables, and of Cuvier for
animals. But the latter had deeply felt how incomplete are our classifications
when we wish to represent the multiplied connexion’ of living beings.* Isidore
Geoffroy had also felt the same, and he tried at least to diminish the imper-
fections. ’

Linear classifications, however arranged, never place a- being except between
two others, that which precedes and that which follows it. Thus they repre-
sent only direct affinities ; they are powerless to represent, even imperfectly,
collateral affinities or zoological analogies. Now the latter have, in a general
view, an importance which must naturally have attracted the special attention
of our author. He soon perceived, like some of his predecessors, that the
primary zoological groups may be divided into secondary groups, composed of
species which correspond to each other, as it were, term by term. He thought,
with reason, that these series ought to be represented, and he was thus led to
that parallellic classification which he has applied especially to the mammifers.
However, Isidore Geoffroy, no more than Cuvier, regarded his classification
as presenting all the relations of beings with each other. He only saw in it a
less imperfect representation of what exists. He has several times expressed
himself very clearly on this point, regretting to see his ideas presented ina
manner too absolute, by some pupils who had not half understood them. Here,
as elsewhere, the master was more cautious than his disciples.

We can only name-the volume entitled Essays on General Zoology, (1845.)
It is less a book than a collection of memoirs on distinct subjects, connected
only by the common thought indicated by the title. We shall refer to some
of them hereafter.

To construct a general system of zoology was, in fact, the constant object of
Isidore Geofiroy. It betrayed itself everywhere, and even his public instruc-
tion served to manifest it. At the museum, and still more at the Sorbonne,
several of his special courses of lectures were partly devoted to the exposition
of ideas connected with this purpose, which never quitted him, even when he
seemed farthest from it. .

But these ideas, as they ripened by incessant study, expahded more and
more. He perceived that in general questions, living and organized beings
cannot be isolated. ‘Even at the limits of the animal kingdom, the application
of the method remains incomplete, the demonstrations for the most part unfin-
ished, the synthesis only partial.”t Thus he was led insensibly, and, as it
were, in spite of himself, to publish, not a general zoology, but a General Nat-
ural History of the Organic Kingdoms.

The first volume of this book, which was to be the epitome of the labors of
a whole life, appeared in 1854; the second in 1859. The first half of the
third volume was published in 1860. ‘This is all that Isidore Geoffroy has
been able himself to give to the public. What pious hands have collected will,
perhaps, complete this volume and the second part of the work; the rest is
forever lost.t

It is especially for this reason that the premature death of Isidore Geoffroy

*The formal declarations inserted by Cuvier in one of his last works on the essential dis-
tinctions between the classifications and the method, has too often been forgotten.—( General
History of Fishes, by MM. Cuvier and Valenciennes.—( Introduction by Cuvier. )

tGeneral Natural History of the Organic Kingdoms, preface.

¢This first part extends from Chapter VILI to Chapter XI, inclusive. Besides, the family
have tound four sheets, entirely corrected and ready for the press; two partially corrected ;
three sheets in the first draught, and a manuscript reaching to the end of Chapter XLX. We
may then expect that the third volume will be completed, and that there will, perhaps, only
be wanting’ the definitive conclusion which an author sometimes reserves till the last moment,
till he has reviewed and reconsidered his work. But for the latter parts, the most original of

this great work, neither notes nor fragments could be discovered. All was in the head of the
author.

83888 MEMOIR OF M. ISIDORE GEOFFROY SAINT HILAIRE.

is a real misfortune to science. During twenty-six years this man, of the first
order of mind, had in view, in all his works of detail, in ali his lectures, the
development of a class of ideas of the highest importance. We have said
already, and repeat here, who shall take up the work? And even though
some one should step forward to replace him, can it be hoped that his successor
will lay hold of this immense problem with the materials and ability which
Isidore Geoffroy had at his command ?

As if to increase-and justify our regrets, the author places at the head of the
first volume an analytic programme of what his book was to be. He divided
it into six portions, and we have seen that the second part, at most, will appear.
Two-thirds of the work will be forever known to us only by this epitome, the
whole of which, representing at least five or six volumes, hardly occupies three
pages.

Unfinished, or rather only commenced as it is, the General Natural History
of the Organic Kingdoms has rendered essential services. Isidore Geoffroy
had time to pronounce on some questions which touch on the very foundations
of biological sciences, and it is of importance that his judgment on the greater
part of them should be known. Heir of Buffon, Lamarck, and of Etienne
Geoffroy, having constantly held aloft the banner of the philosophic school, no
one can less be suspected than he of having sacrificed to considerations foreign
to science. His opinions are the most formal condemnation of certain very
ancient doctrines, which some have lately sought to revive in the name of science
and philosophy. é

Such, for example, is that which puts in doubt the reality of species, by
admitting that plants and animals may vary indefinitely, and bring forth
series of individuals so distinct as not to be confounded. No one can pronounce
against it more clearly than our author. Hedoes more. He shows that in spite
of theoretical ideas, a// serious naturalists have arrived at the same conclusion
on this question, as soon as they abandon the vague ground of hypothesis to
place themselves on that of facts. He has said, and he could say with reason,
that in spite of the profound difference of their general doctrines, Lamarck
and Cuvieragreed on this fundamental question. Both, in this, contradicted
some of their abstract principles; each had to take some steps towards the
truth in an inverse direction. The one had to abandon the theory of iadefinite
variability; the other, that of absolute fixity. hus they met in the belief
which was that of the better years of Buffon, that of Isidore Geoffroy: the belief
in the limited variability of species, the result of which is, that the forms and
certain functions may sometimes be modified within very extended limits, while
the essence of the being remains unaltered.

In Buffon, no more than in Geoffroy, was this belief the result of mere
hypothetical views; in both it was the result of a deep study of facts. ‘The
former, before reaching it, had passed through the extreme doctrines indicated
above; the latter, enlightened by this example, and taught by what he had
under his eyes in the menagerie of the museum, saw the truth from the first,
and supported it by new proofs.

Man could not escape the study of the savant who embraced the whole of
the animated creation. He was a prominent object of the researches and medi-
tations of Isidore Geoffroy. As early as 1842, in a short article of the Dic-
tionnaire Universel des Sciences Naturelles, the author rejected the views gen-
erally adopted on the authority of Blumenbach and Cuvier, as to the subject of
the relation between man and the lower animals. He insisted that the order
of bimana should be struck out, as removing us too far from the monkeys, if we
see in man only the material being ; and bringing us too near them if we regard
the whole of human nature. Ata later period, in his lectures,* and in his

* Lessons on Anthropology, given at the Faculty of Science, and summed up by M. De-
vaille, 1856.

MEMOIR OF M. ISIDORE GEOFFROY SAINT HILAIRE. 389

General Natural History, he repeated the same criticism, and contended strongly
for the admission of the human kingdom, first proposed by a Frenchman, the
Marquis de Berbengois,* and since adopted by a number of eminent men in
Germany and France. oe

Is this kingdom, like the others, divided into groups distinct and, to a certain
degree, independent of each other? Does it contain a, great number of species
which may be compared to the animal and vegetable species, or else does it
include but one, namely, man?t We know that this question is still agitated,
and even with redoubled ardor. The answer of Isidore Geoffroy is that of
Buffon, Cuvier, Etienne Geoffroy Saint Hilaire, Miller, Humboldt, and others,
He pronounces in favor of the unity of the human species.}

The General Natural History of the Organic Kingdoms stops at the funda-
mental principles of biology. he author proposed to present, in the third part,
the general facts relative to organized beings, considered in themselves or in their
organs ; the fourth was to be devoted to the general facts relative to the instincts,
the habits, and, more gencrally, to the exterior vital manifestations of organized
beings; the fifth, to the general facts relative to the successive and present dis-
trib..ion of organized beings on the surface of ,the terrestrial globe; in short,
the sixth was to comprise the expositions of what the author calls xatural phi-
losoply. There he was to show the convergence of all science towards philo-
sophic unity ; to explain his views on the totality of organic nature; to show
in the perpetual changes of the details and the permanence of general laws,
whence results unity through variety; the harmonic succession of individual
and general phenomena, which produce progressive harmony. Certainly no one
ean glance over this magnificent programme without a feeling of bitter regret.
The History of the Organic Kingdoms will remain like one of those unfinished
edifices whose factitious ruins sadden the mind by merely giving a glimpse of
what the edifice would have been, by revealing the grandeur of the plan and
the genius of him by whom it was conceived.

There is an additional proof of the intellectual worth of Isidore Geoffroy.
Profoundly devoted by sentiment and conviction to the doctrines of Etienne
Geoffroy, he had to guard against a very natural inclination to tread too closely
in the steps of this venerated guide. While he retained his filial regard and
erected monuments of it|] to his father, no one can mistake him. Isidore
Geoffroy was like one of those eminent artists who, after having been a docile
pupil of a great master, after having copied his manner, have created one
in their turn; have conceived and executed works stamped with their own

* Journal de Physique, 1816. M. de Barbengois had called it the moral kingdom.—(See
General Natural History of the Organic Kingdoms.)

tA polygenistie belief had sometimes been attributed to Etienne Geoffroy Saint Hilaire.
In the work which he has devoted to the memory of his father, Isidore Geoffroy has warmly
protested against this assertion.—(Life, Labors, and Scientific Doctrine of Etienne Geoffroy
Saint Hilaire, 1847.)

¢ According to the lectures reported by M. Delvaille, Isidore Geoffroy, in 1856, only pre-
sented this doctrine as having in its favor the largest share of probability. To judge by the
conversations I had with him less than a year before his death, his convictions on this point
had become much more decided. Unfortunately, he did not reach this part of his work.

§ Abstract of the Analytic Programme placed at the head of the first volume.

|| It is well known thatthe son of Butfon caused to be placed at the town of Montbert,
where his father had worked, a column which bore this inscription:

Excelsa turris, humilis columna,
Parenti suo filius Buffon. (1780.)

Isidore Geoffroy conceived the nobler thought of raising to his father a more durable mon-
ument by publishing the work entitled Life, Labors, and Scientific Doctrine of Etienne
Geoffroy Saint Hilaire. The General Natural History of the Organic Kingdoms has asa
dedication this verse of Dupoty:

“Méme etait fait per moi, cet ovrage est le tien.” (Even though done by me, this work is thine.)

390 MEMOIR OF M. ISIDORE GEOFFROY SAINT HILAIRE.

genius, and have thus taken rank beside their teacher. We have pointed out
what our author was as a man of pure science; it yemains to show him under
other relations. But here we may be more brief. His labors of practical
science are more generally known, and what is important to point out is the
filiation, too often unperceived, which unites them to the preceding.

To every one who applies his mind to general questions of zoology, the do-
mestic animals have an importance of the highest order. The extent and
number of modifications presented by each of their species at once raise and
resolve a crowd of problems which touch on the most delicate questions of
physiology, even on the history of man himself. Thus they early attracted
the attention of Isidore Geoffroy. We find the proof of this in the article
Mammifers, in the Dictionnaire Classique, which we mentioned above, and
still more in the Essays on General Zoology. We find, amongst others, a
memoir relative to the possebility of elucidating the natural history of man by
the study of the domestic animals.* 'The author examines at first the analogy
which exist between the variations of the domestic animals and those of the
human races, and points out the close connexions presented by these two orders
of facts. ‘Then he shows how the determination of the original country of a
domestic species may throw light on the history of the migrations of a people.
These ideas were to be afterwards extended and completed.t

Inthe same volume we find a treatise on the domestication of animals,t which
was the first step in a path in which the author was so greatly to distinguish
himself. This simple memoir furnished the basis of labors more and more mul-
tiplied and important, and was transformed into an octavo volume of more than
five hundred pages, entitled Domestication and Acclimatation of the Useful
Animals. We know, also, that the ideas put forth by the author of this book
have assumed a concrete form, and have been reduced to practice by the foun-
dation of the Society of Acclimatation and the creation of the Garden of Accli- -
matation. These two establishments are truly the works of Isidore Geoffroy,
and should rank amongst his best. If, in their beginning, they excited some
distrust and some raillery, the first of these sunk under the conciliating and pru-
dent direction of the founder; the second disappeared before established facts.
Thus their progress was rapid, their future soon assured. Isidore Geoffroy thus
left, beside his books, two institutions not less durable than his fame; and if
his loss excited uneasiness in the minds of those who had adopted his plans, it
was soon dissipated by the choice of his successor.§

The results of the publications of Isidore Geoffroy on: practical zoology, in
the foundation of the two organizations which I have just named, deserve to be
pointed out no less for their immediate and visible effects than for the influence
which they have already exercised, and which must continue to be more and
more felt. Hitherto the natural sciences, zoology especially, had. been some-
what despised by those who claim the title of practical men. They were
merely considered as a species of knowledge calculated to amuse the mind, but
without practical utility. For this cause they were rejected, as were chemistry
and geology by the metallurgists and miners of the last century. Thanks to
Isidore Geoffroy, and to the movement which he originated, these prejudices
begin to be dissipated; they may, perhaps, disappear slowly, but certainly it
will be at, length understood that zoology has also its applications; that it
ought to be to the breeding of animals, and to all that we procure from them,

_ * This treatise, an abstract of which was communicated to the Society of Natural Sciences
in 1835, had been read to the Academy in 1839. It figures in the Reports.

+ General Natural History of the Organic Kingdoms.
{This work had appeared, but less complete, in the Encyclopédie Nouvelle. »
§ It is known that this successor is M. Drouyn de l’Huys.

+. ¢

.

MEMOIR OF M. ISIDORE GEOFFROY SAINT HILAIRE. Doaie

that which the physico-chemical sciences are to operations upon brute matter.
. It is true, Buffon, and especially Daubenton, had acted upon this idea; but,
less fortunate than their sutcessor, and perhaps beginning too early, they left
no real impress on the minds of the people. It will not be so with the work
of Isidore Geoffroy ; and this is one of the special results of that life so well
occupied. Here, as everywhere, pure science appears the mother of practical
science—a mother fruitful in proportion as she is exact and elevated.

In speaking of the works of Isidore Geoffroy, M. Milne Edwards has said:
“ All display a profound erudition and bear the stamp of a mind wise, elevated,
and generalizing, and the purity and elegance of the style enhance their merits.’’*
In speaking of his colleague’s public instruction at the Faculty of Sciences, M.
Delaunay expressed himself in a similar manner: “‘M. Isidore Geoffroy,” says
he, “was a most distinguished professor. He had an easy elocution, and ex-
pressed himself with graceful simplicity, without any pretension to eloquence,
and captivated the attention of his audience at once by the clearness of his
explanations, and by the art with which he could group isolated facts around
the principal ideas which he sought to illustrate.’’}

These appreciations are just, and they characterize well the eminent man of
whom we speak. His lucid mind embraced at once his whole subject; conse-
quently his ideas arose logically one from the other, and, as it were, co-ordered
themselves. His words translated faithfully his thoughts, clearness of expression
only reflecting clearness of conception. Thus his speech kindled at times, and
he never wanted striking images and happy comparisons to render the most
comprehensive or profound ideas, becoming thus an orator without effort. His
lectures were always as well attended as his works were widely read.

It was at the museum, in 1829, that Isidore Geoffroy, at the age of twenty-
four, first appeared as a professor. He was then an assistant to his father, and
took ornithology as the subject of his lessons. The following year he delivered,
_ at the Athenzeum, the remarkable course of lectures of which we have already
spoken. Having been appointed, in 1837, assistant to his father at the Faculty
of Science? in Paris, he soon quitted this temporary chair to go to Bordeaux,
with the title of dean, to organize the Faculty of Sciences created in that city,
(1838.) But this task finished, he returned to Paris, and in 1840 was named
inspector of the Academy, and charged with the duty of inspector general of
the University. At the same time that he fulfilled these high functions, in
which civil administration is so closely connected with the best interests of
science, he replaced his father at the museum, the latter being struck with blind-
ness, as had been Lamarck and Savigny before him. In short, in 1841, this
position having been made permanent, the veteran of science yielded the place
to the young soldier whom he had trained ; and Isidore Geoffroy received, during
his father’s life, the succession which, for a long time previously, he had in great
measure administered.t

In effect, from 1824, the youthful savant had discharged the duties of assistant
naturalist at the Jardin des Plantes. In this office he had to superintend and
direct not only the colleetions of mammals and birds, but also the menagerie,
founded by Etienne Geoffroy, (1793.). He had devoted himself, heart and
soul, to this double task; but he became, perhaps, still more eamest in it when
he was made the official chief of this very important part of the museum. All
those who have seen him at work know with what steady ardor he labored to

“Funeral of M. Isidore Geoffroy Saint Hilaire. Discourse of M. Milne Edwards, president
of the Academy of Sciences.

t Funeral of M. Isidore Geoffroy Saint Hilaire. Discourse of M. Delaunay, in the name
of the Faculty of Sciences.

{In 1844 he became titular inspector general, and he exercised the functions up to the

pie ae he, replaced M. de Blainville as professor of zoology at the Faculty of Sciences,
(1850.

392 MEMOIR OF M. ISIDORE GEOFFROY SAINT HILAIRE.

enrich these collections of dead and living animals. The galleries soon became
too small to contain all that Isidore Geoffroy procured for them; sometimes by
using the slender resources which the too scanty fifhds of the museum placed
at his disposal; sometimes by availing himself of the authority of the establish-
ment and his own personal influence.* Ata time when it was the fashion to
find fault with all that concerned the museum, objection was often made to the
crowded condition of the cases, and the professor who had the administration of |
this portion of our riches was reproached for neglect. It was forgotten that
this was the most striking proof of his exertions, for had he been less indus-
trious, the localities sufficiently capacious for his predecessors would have sutliced
for him. .

What we hae just said of the galleries applies equally to the menagerie.
But could it be otherwise? The number of living specimens collected in the
parks of the museum was tripled in twenty-five years,t while the disposable
space remained almost the same. What minute and constant care did it not
require to utilize this ground so parsimoniously granted to the first scientific
menagerie ever formed ; to struggle against conditions often deplorable; to meet
expenses constantly i increasing , even when the budget was restricted in conse-
quence of political events. It was in the midst of such difficulties that Isidore
Geoflroy succeeded in developing the noble creation of his father, and in making
it serve the advancement of pure as well as practical science.

Some of the first acclimatations attempted in our age have been produced in
this menagerie. I need only recall the Egyptian eooset It is known that
this fine species, brought to France by Etienne Geoffroy, and since then almost
constantly reared in the museum, has furnished, for the first time, a race truly
European, characterized by an increase of size and a change of color, but especi-
ally by a delay of about four months in the time of laying its eggs—a delay
which brings the mother and her young into harmony with the new climate to
which they are subjected. We may also mention, in passing, the yaks, three
of which, arriving at the museum in 1854, have increased to a herd of more
than twenty head, without the death of a single one, young or old.

But lect us dwell a little on the part which the menagerie, often considered
as only fit to satisfy a useless curiosity, has furnished to the scientific labor of
Isidore Geoffroy. This collection of living animals was to him a field of con-
tinual experiment, and he owed to it the solution of some of the most delicate
questions of physiology and of general zoology. It was by means of it that he
was able to vanquish the greatest, one may say the last, difficulties opposed by
Cuvier, Blainville, and Ae naturalists, to the opinion of Guldenstiidt and Pallas,
as to the filiation which connects the jackal with our domestic dog. It was
from it that he sought instruction on the fecundity of metis and hybrids. It is
to the facts collected in this enclosure, and appreciated with rare*clearness of
judgment which none could fail to recognize in him, that he was indebted for
avoiding, in the solution of such delicate questions, the opposite exaggerations
which have alternately reigned under the sanction of great names in scicnce.

The museum, with its its galleries and its menagerie—the Society of Accli-
matation and the garden of the Bois de Boulogne—formed the world in which

*In 1828 there were at the museum 7,500 stuffed birds and mammals; in 1885, 11,750;
in 1861, 15,500. Besides the magazines contained at the latter period, 12,000 skins in a
perfect state of preservation.

+ In 1524 the menagerie possessed 283 birds or mammals; in 1842, 420; from 1850 to
1861, 900, on an average.

tThe Egyptian goose lays naturally about the end of December. Those reared at the
museum for some generations laid, in 1844, in February; in 1846, in March; and since then,
in April. (Acclimatation and Domestication of the Useful Animals. ) Itis one of the most
striking examples that can be quoted of the influence of the surrounding medium.

MEMOIR OF M. ISIDORE GEOFFROY SAINT HILAIRE. 9893

the life of Isidore Geoffroy was passed; a world very small, to judge by its
extent, but very large to him who could see in it an epitome of the living crea-
tion; and our lamented compatriot found it extensive enough to exercise all
the faculties of his mind and the peculiarities of his character.*

The books of which we have sketched the tendency and the results attest the
activity of his mind, while his character was not less seen in the mixture of firm-
ness and gentleness with which he exercised his functions. At the institute and
the museum his word had always a real authority over his colleagues. At the
Society of Acclimatation and elsewhere many thought they followed the inspi-
ration of their own minds when they only yielded to an influence that could
hide itself, the better to reach a desired end. Everywhere—and this is not his
least praise—his subordinates cheerfully obeyed his orders, always clear and
precise, or accepted his decisions, dictated by kindness and justice.

Isidore Geoffroy had known all the joys of the heart, and he had felt, too, all
its sorrows. <A twin sister, worthy to understand him, had been the companion
of his childhood.t At the age of twenty-five he married Mademoiselle Louise
Blagnet ; and all who have known this young lady remember her cultivated
mind, affectionate disposition, and graceful manners. A son and daughter, the
fruits of this union, brought the gaiety of childhood into this united family,
over which was shed the influence of the gentle good sense of his mother and
the brilliant glory of his father, while he himself was becoming daily more dis-
tinguished. It was a happiness too complete to last. Etienne Geoffroy lost
his sight in 1840, and although the patient resignation of this martyr of science §
tended to soften to his family the pain of this trial, all must have felt that their
happiest days were over. The head of the family passed away the 19th June,
1844, and shortly after Madame Isidore Geoffroy was seized with one of those
incurable maladies which wear out slowly the springs of life. Her husband
had long to endure the anguish of witnessing the suffering of a beloved being
whose days are numbered. She died the 20th November, 1855. he sister
forgot her own griefs in consoling her brother and mother. She, also, died,
almost unexpectedly, the 13th June, 1860.

One should have known Isidore Geoffroy intimately to comprehend the effect
produced by these successive losses on this savant, apparently so calm and even
cold, but, in reality, so warm and loving. “This poor, torn heart felt inees-
santly the loneliness of its home, the absence of that which comforts, tran-
quillizes, vivifies.” Everywhere he found “the bitterness of regret, the remem-
brance of happiness once possessed.”’|| To escape, at times, these heart-rending
thoughts, he plunged into study with a sort of desperation. He accepted, on

*Tn speaking of the wonderful development of the collections of this establishment, Etienne
Geoffroy had said: ‘‘The museum is becoming a Noah’s ark.” (Progressive Studies of a
Naturalist. )

t Isidore Geoffroy had had twin sisters. M. Mademoiselle Anais Geoffroy Saint Hilaire
died at the age of 19. The other, Madame Stephanie Geoffroy Saint Hilaire, survived till
June, 1860. The pen of a friend has rendered a just and pious homage to this lady, whom it
is impossible to know without loving, and who had _herself known every grief that could
afflict a delicate and affectionate heart. (Les puit de la douleur, by Madame Marie Pape
Carpentier. )

¢ March 20, 1830.

§ During his abode in Egypt, and in consequence of hard work, Geoffroy Saint Hilaire had
been seized with ophthalmia, and had remained twenty-nine days without sight. “I shall
become blind again in my~old age,” he had often said. He did not the less continue to write
great part of the night, reserving the day for his researches. This habit certainly contributed
much to bring on the infirntity, the anticipation of which never stopped him for a single
moment,

|| Sixth annual session of the Society of Acclimatation. Discourse of M. Drouyn de l’Huys,
president. (Bulletine de la Societé.) If other orators here dwelt more on the merits of
Isidore Geoffroy as a savant, none has so well displayed the amiable qualities of the man.

:

394 MEMOIR OF M. ISIDORE GEOFFROY SAINT HILAIRE.

all sides, the occupations which presented themselves to him, and found time
for all. He felt, indeed, that his life was at stake in this struggle of grief
against labor. ‘Can the bow be always bent and not break?”* said he; and
at that moment he doubtless felt the attacks of the malady which was to carry
him off, but he did not the less continue this consuming strife.

He tells us himself that from the:month of November, 1860, he had felt his
head much fatigued, and had sometimes been obliged entirely to suspend his
labors. These symptoms returned in the course of the summer of 1861 in a
more threatening manner. By the advice of his physicians he set out for Swit-
zerland, in the course of September, in the hope of regaining the strength which
seemed failing him, and he even went as far as Italy. Returning about the
middle of October, he thought himself able to resume his studies, but his weak-
ness soon reappeared. Some uncertain periodical symptoms having given the
idea of an influence of malaria, he was advised change of air, and went to
Neuilly.t He remained there scarcely a fortnight, when, his condition be-
coming worse, he was taken back to Paris, only to lay himself upon a bed from
which he never rose again; and in that house, in the museum which, for sixty
years, had attracted the most distinguished men of all countries, there remained
only a widowed mother mourning over all that she had loved. May the vene-
ration with which she is regarded, and that whicb is attached to the memory
of those who were so dear to her—may the affectionate attentions of the young
family which has gathered around her mitigate her sorrows.t

* These expressions occur in a letter of Isidore Geoffroy quoted by M. Drouyn de l’Huys.

tM. Albert Geoffroy Saint Hilaire, first director of the Jardin Zoologique d’ Acclimatation,
displays, in developing and carrying on this establishment, the same intelligence and filial
devotion which animated his father, where, at about the same age, he labored in the menagerie
of the museum.

¢ Madame Geoffroy Saint Hilaire still occupies the home where she has lived since 1804.
The ministerial decision which assigns it to her has only ratified the universal wish of the
former colleagues of Etienne and Isidore Geoffroy. The daughter of the latter, and his son-
in-law, M. d’Audrey, have come to live with their grandmother, bringing with them her
great-grandchildren,

STUDIES ON THE PHENOMENA OF CONTACT.

THE CATALYTIC FORCE,

OR

STUDIES ON THE PHENOMENA OF CONTACT.

A PRIZE MEMOIR, BY T. L. PHIPSON, D. S.—TRANSLATED FOR THE
SMITHSONIAN INSTITUTION BY C. A. ALEXANDER,

QUESTION. ‘‘The existence of what is called the catalytic force, in which the explanation
‘of many phenomena has been heretofore sought, having become more and more doubtful, the
society desires a rigovous examination of the phenomena which some savans continue to
explain by that force.” — Question proposed bythe Societe Hollandaise.des Sciences. Haarlem,
1858.

~The phenomena attributed to the catalytic force, such as the incandescence
of platina in the vapor of alcohol, the union of oxygen and hydrogen by means
of platina, of pumice-stone, of humus, &c., fermentation, eremacausis, putrefaction,
&c., &c., are extremely common, and occupy a prominent place in chem-
ical studies. At first glance they all appear to offer an exception to the general
laws of chemical affinity. There is, however, nothing of the kind; and these
phenomena which are so often met with, and which, so to speak, have become
general, afford, when we rigorously examine them, the same character of every
other chemical reaction.

One thine which has especially conducted me towards what I regard as the
true interpretation of catalytic phenomena, is the study which has been recently
made of ozone and the allotropic conditions of certain bodies other than oxygen.
The production of ozone by the contact of phosphorus and moist air may be
regarded, with the combination of hydrogen and oxygen by platina, as the
type of catalytic phenomena. .

The experiments of MM. Marignac, Fremy, Becquerel, Andrews, &c., &c.,
prove, in an unexceptionable manner, that ozone is pure oxygen, as the diamond
is pure carbon. . If, then, we could succeed in determining by experiment the
modifications which the molecule of oxygen undergoes in passing to the state
of ozone, an important step would be taken towards the exact interpretation of
all the phenomena of contact.

The properties of ozone, when compared with those of oxygen, are ex-
tremely remarkable and too well known to chemists to require full recapitula-
tion here. It will suffice, I think, to say that ozone is to oxygen what
oxygenated water is to water—it is oxygen whose polarity is the most decided
possible; that is, whose tendency to combine with other bodies is developed
in the highest degree. ‘ :

We must dwell a little on the phenomenon of polarity. Let us consider what
chemists understand by this word. When two different bodies are about
to combine, we know that one passes into the electro-positive state, the other
becoming, at the same time, electro-negative. Thus, when we add a dase to an
acid, the base becomes electro-positive, the acid electro-negative ; and when
the combination is effected, the electricities of opposite names are given off. It
is then well established, at the present time, that a molecule A,-on the point of
combining with & molecule B, takes an electricity opposite to that of the latter.

396 STUDIES ON THE PHENOMENA OF CONTACT.

Fig. 1. We call this polarization ; the molecules seem
A _B to assume poles. ‘lhe combination completed, the
a C) am ae O- opposite electricities are given off, as the second
figure shows, and, by intercepting them with a
galvanometer, we identify their nature; we prove, by direct ex- Fig. 2.

periment, that electro-negatzive bodies, like the acids, give off the AB
positive electricity, while the bases or electro-positive bodies, AYE)
under these circumstances, give off the negative electricity. , .

This principle governs all chemical reaction, however com-
plicated it may appear. And whatever may be the modifica- \, j
tions recently introduced into our ideas respecting light, heat, aa
electricity, aflinity, &c., by the imposing doctrine of the correlation of physical
forces, we shall continue, in speaking chemically, to consider chemical reaction,
the combination and decomposition of bodies, in this manner. For, without
affirming that this is, at the present epoch of science, the most rational manner
of consideration, we are able, in this way, not only to present a theory easily
apprehended and borne out by all experiments, but have it further in our power
to explain, to a certain point, by a profound study of the phenomenon of polarity,
almost all the facts thus far observed in the vast domain of chemistry.

I shall not inquire, in this place, whether chemical affinity be a force apart
sui generis, or a necessary effect of the polarization of molecules. Something
will be said on this subject towards the close of this memoir. I affirm only
that the phenomenon which we call polarity accompanies and controls all com-
binations and decompositions of bodies.

This being premised, it still remains to demonstrate that the polarity of a
body is not fixed; that it varies according to the bodies with which it is brought
into contact. To cite an example familiar to all my readers, chlorine, one of
the most electro-negative of metaloids, becomes electro-positive in its relations
with organic bodies, and even in relation to oxygen, under certain circum-
stances. What is thus said of chlorine is also applicable to iodine, bromine,
fluorine, &c.; in a word, to all analogous bodies. Sulphur, agreeabty to the ex-
periments of M. Berthelot, is sometimes positive, sometimes negative, according
to circumstances. Chlorine, in the chlorides, is electro-negative; in the
chlorates, it is eleetro-positive; and in them the nitrate of silver does not evince its
presence, &e., &c, Thus we find that the polarity of a body changes according
to the bodies with which we place it in contact. The change consists in the
body submitted to experiment becoming electro-negative or electro-positive,
from having previously been clectro-positive or electro-negative.

But we can modify in a different manner the polarity of a body; that is, we
can render it more or less electro-positive, more or less electro-negative, and that
without the body entering into combination with one of those which induce
this change. Thus, by the contact of a stick of phosphorus, the polarity of the
oxygen contained in a volume of humid air passes into an allotropic state—into
ozone. Its polarity is thereby modified to an extraordinary degree; it is
much more electro-negative than in other circumstinces. If we decompose
water by means of the pile, and collect the oxygen produced iu the pores of a
charcoal pole, this oxygen is modified in the same manner.—(Osann.) If
we disengage it from the bi-oxide of baryta by sulphuric acid, at the ordi-
nary temperature, the effect is the same.—(Houzeau.) If, observing certain
precautions, we disengage it by heat from the peroxide of lead, from the oxide
of mercury, &c., we find that a certain quantity is in the state of ozone.—
(Schénbein.) When ordinary oxygen enters into combination with certain
organic bodies, it passes into the state of ozone.—(Schinbein, Kuhlmann, and
Phipson.) Not needlessly to multiply these examples, we shall only say that
the same is the case with chlorine, with bromine, (Andrews, ) and with hydro-
gen, ( Osann,) as shown by experiments results of which can bear but one inter-_

aot tna,
“weenee”

2
,
?

STUDIES ON THE PHENOMENA OF CONTACT. 397

pretation. Ordinary hydrogen, disengaged from water by zine and sulphuric
acid, exerts no action on a solution of sulphate of silver; the hydrogen disen-
gaged from water by the pile decomposes that salt.

Electric action is peculiarly effective in augmenting or diminishing the
polarity of a body. Thus oxygen may be converted to the state of ozone by
the electric spark. Let a piece of copper and one of tin be placed in two
capsules of porcelain, and an acid be poured on the two metals; they will be
attacked very nearly in an equal degree. But if the tin be placed in the same
capsule, and in contact with the copper, and the acid be then added, the tin alone
will be attacked, and more actively than in the first case, because its polarity on
account of its contact with the copper has become greater than that of this
metal, and the acid will not act on the copper until all the tin has been dissolved.

We particularly desire our readers to bear this experiment in mind, for
what we shall adduce in the sequel for the purpose of demonstrating what
passes in catalytic reactions will be, in effect, but little else than modifications
of that which has just been cited..

When the polarity of a body is strongly modified, such body is styled
“allotropic,” (from adotporos, of different nature.) Thus ozone is allotropic
oxygen; the chlorine of Andrews is allotropic chlorine ; the hydrogen produced
by the pile, and which decomposes sulphate of silver, is allotropic hydrogen, &e.

But this allotropic state of bodies is but slightly permanent, as will be here-
after seen; and, further, we shall endeavor to prove that bodies assume this
state at the moment when they enter into combination. In regard to this I
shall first cite my own experiments and observations on oxygen. M. Schénbein
having expressed an opinion that the action of oxygen on certain organic bodies,
such as venous blood, &c., depends on the presence of a substance capable
of transforming oxygen into ozone, I was led to study this allotropic modifi-
cation of oxygen under the same point of view.

First, I repeated and confirmed the ingenious experiments of the learned
chemist of Basle, in which he studied the action of ozone in the mushroom;
and these studies appear to me to cast light on the subject with which we
are occupied Itis known that the flesh of certain species of the mushroom and
boletus (among others the Boletus luridus, B. cyanescenus, &c.) possesses the
remarkable property of changing color when broken and exposed to the atmos-
phere. For instance, the internal tissue of the boletus luridus becomes blue under
these circumstances. Now, experiment shows us that this boletus contains a
colorless, resinous principle, soluble in alcohol, and this aleoholic solution is
affected, as regards oxygen and ozone, in the same way with the alcoholic
solution of the resin of guaiacum, which has been employed by M. Schénbein
and myself in some experiments as a test for ozone. This resinous prin-
ciple, which is separated from the boletus by means of alcohol, can assume no
color spontaneously from the air when it is separated from the mushroom ; but
in the parenchyma of the vegetable it promptly becomes blue on the least con-
tact with oxygen. Experiment further proves that the expressed juice of
several mushrooms contains an organic principle possessing ‘the property of
transforming oxygen into ozone, so that, by causing a current of air to pass
through this juice, a certain quantity of oxygen is retained in the liquid in the
state of ozone, the presence of which is indicated by mixing with the liquid a
little of the alcoholic solution of guaiacum, or that of the colorless resin of the
boletus. If the liquid contains no ozone, no coloration occurs; if ozone be
present, a deep blue tint is obtained.

I have repeated experiments of this kind upon a great number of different
mushrooms, and on the juice of different phanerogamous plants. I have found
that the peculiar matter which transforms oxygen into ozone may exist in
mushrooms, where the colorless resin of the boletus tribe does not oceur; the
peculiar matter and the resin may be wanting in certain other mushrooms, but

§98. STUDIES ON THE PHENOMENA OF CONTACT.

the first may be formed in the expressed juice after a certain lapse of time. I
entertained no doubt, therefore, that this peculiar matter, which effects the
transformation of oxygen into ozone, is of the nature of ferments. I have
verified its presence in all phanerogamous plants whose juice gives a blue color
with the resin of guaiacum. It seemed desirable, furthermore, to determine
whether the organic acids had anything to do with this color, for some of
these acids react, we know, on pectose, starch, sugar, &c., as yeast does. My
experiments have, however, satisfied me that the organic acids have no imme-
diate action on an alcoholic solution of guaiacum; that these acids do not pro-
duce a blue color in the tincture of guaiacum when alone or when previously
mixed with the liquid obtained from mushrooms, the juice of which does not
act upon this reagent. On the contrary, certain acids, for example tartaric,
citric, and oxalic prevent the coloration of the juice of certain mushrooms, whose
juices act on the alcoholic solution of guaiacum when these acids are not present.
Although nature then appears sometimes to employ these acids for inducing
metamorphoses, it would seem that they do not act in this case.

From these’ facts I have come to the conclusion that the peculiar matter
spoken of above must be of the nature of a ferment, and the experiments of M.
Sghacht lend support to my opinion; for that chemist believes that the juice of
phanerogamous plants owes its property of turning the resin of guaiacum blue
to the presence of what he calls vegetable gelatine, and he aflirms that this:
substance no longer acts when boiled.

Among my experiments of this kind I will cite one which is easy to repeat.
We know with what facility a slice of apple changes in the air; its surface
becomes brown in the course of a few minutes. This coloration is known to be
owing to the action of oxygen; it is a commencement of eremacausis,

Now I think I have proved, as will be seen in the sequel, that when oxygen
acts thus on organic bodies, producing the phenomenon known by the name of
eremacausis or slow combustion, this oxygen is always in the state of ozone at
the moment when it reacts. ‘To verify this with the slice of apple, we need only
diffuse over the fruit a drop or two of the tincture of guaiacum; at the end of
three or four seconds the reagent changes to a bright blue color. Let it be ob-
served that this tincture, exposed to the air on glass, porcelain, clean paper,
&e., will not change color for a long time; and, moreover, as has been already
seen, the organic acids are inactive in this phenomenon.

I have carried my experiments further, and have arrived at the conclusion
that the first phase of all fermentation or eremacausis by the influence of the air
consists in the transformation of the oxygen of the air into ozone. ‘Thus, as in
the most ordinary cases of inorganic mineral chemistry, all commences with a
phenomenon of polarity.

What has just been said is particularly striking, as regards the phenomena
presented by the resinification or oxidation of certain essential oils. ‘The extra-
ordinary manner in which the oil of turpentine (térébenthine) exalts the activity
of oxygen is now known tovall chemists. The acrated turpentine transforms
sulphurous acid: into sulphurie acid, the oxide of lead into peroxide, arsen-
ious into arsenic acid, &e.—/( Kuhlmann.) Other essences act in the same
manner on oxygen by transforming it into ozone; and in my experiments
I have never yet met with an essential oil which did not exercise this property.

Still further, in examining different fats and fixed oils, I have been convinced
that they possess, in a certain degree, as regards oxygen, the same properties
with the essence of turpentine and the volatile oils.

The substances with which I have most frequently experimented are crude
turpentine, the extract of bitter almonds, of cinnamon, of caraway, the balsam
of Peru, most of which were acid and reacted on litmus paper. They produced,
however, uo effect on the ozonoscopie paper until an absorption of oxygen
had taken place.

STUDIES ON THE PHENOMENA OF CONTACT. 899

If we place a very small quantity of one of these bodies on ozonoscopic
paper, and expose the whole to the air, we shall perceive that at the end of a
quarter of an hour the paper begins to be colored, and the coloration proceeding °
from the deposit extends itself further and further. The same thing takes place
with solid fats, stearine, margarine, &c., and with the fixed oils. One of
the substances which most readily undergoes eremacausis is liquid sugar,
especially if it has been extracted from honey. If we place some of this sugar,
already embrowned by the action of oxygen, at the bottom of a flask, and sus-
pend from the stopper an ozonoscopic paper, this last becomes colored in a very
short time.* There are reasons, also, for thinking that starch itself, under
certain circumstances, transforms oxygen into ozone, and here lies, in my
opinion, the cause of the discussions which have lately arisen on the efficacy
of this paper as a reagent for ozone; ioduretted starch, when dry and
placed beyond the influence of disturbing agents, such as hyponitric acid, &c.,
is an excellent test for ozone; but ioduretted starch, wet and exposed to
the solar light, can furnish only doubtful results, to say the least, for, in under-
going eremacausis, it should transform oxygen into ozone like other organic
bodies. There can never be a doubt of the presence or absence of ozone when
we employ mineral reagents, such as sulphurous acid, the black sulphuret of lead,
which ozone immediately transforms into sulphuric acid and into white sulphate
of lead; or even with the blue sulphate of indigo, with which ozone produces
colorless tsatine. J

The ethers and the alcohols while absorbing oxygen also transform it into
ozone. Sulphuric ether, in this instance, promptly discharges the color
from a solution of indigo. A solution of iodide of potassium in alcoholic ether
soon yields a precipitate of iodine through the action of the air, (a fact well
known to photographers who employ collodion,) because ether attracts oxygen
and converts it mto ozone. Ordinary oxygen, it is known, does not precipitate
the iodine from the iodide of potassium. Moreover, the acetic acid produced during
the reaction of air on alccholized ether is not the cause of the precipitation
of the iodine, as we may convince ourselves by direct experiment. In fact, if
acetic acid be added to the solution of iodide of potassium in aleoholized ether,
*he jodine is not precipitated until after the lapse of several hours. When this
mixture is oxidized, on the contrary, the precipitation of the iodine commences
immediately. This phenomenon may be artificially produced by plunging an
iron wire; heated to redness, into a mixture of the vapor of ether and air; by
then pouring ioduret of potassium into the flask the iodine is at once disengaged.
This last experiment was devised, I believe, by M. Hardwich.

We may add to what has been just said in relation to organic bodies, that M.
Schénbein, by employing the alcoholic solution of the resin of guaiacum, has
succeeded in proving that the oxygen furnished by the action of heat on the

o
oxides of gold, of mercury, of platina, of silver, as well as on the peroxides

*This is one of the first experiments which demonstrated to me that organic bodies can
transform oxygen into ozone. This action of sugar on oxygen may be made manifest in
another manner. If we plunge a bit of metal—iron, for instance—into a solution of any sort
of sugar, we observe that the iron is rapidly and thoroughly oxidized where the metai is in
contact with the sugar and the air; that is, at the surface of the liquid. Ifthe metal is com-
pletely submerged in the solution it is not oxidized at all, or, at least, a very long time must
elapse for oxidation to manifest itself. The corrosive action which sugar exerts on iron was
long since observed, and the captains of iron trading-vessels are often averse to carrying
cargoes of sugar for this reason. This corrosive action is owing to the fact that sugar (es-
pecially impure sugar or molasses) transforms the oxygen of the ambient air into ozone, which
actively aitacks the iron where it is in contact with the sugar and the air. ‘The result, in the
experiment above cited, is the formation of an abundant red precipitate, the larger part of
which is oxide of iron. A combination is at the same time formed, which has been analyzed
by Dr. Gladstone, and which is (C!2 H!! OM FeO.) Itis impossible to produce this combiia-
tion directly with sugar and the iron oxide. Many other metals are attacked like iron when
placed in these cireumstances—copper less than the others.

400 STUDIES ON THE PHENOMENA OF CONTACT.

of lead and of manganese, contains traces of ozone. The quantity of this last
depends on the temperature at which the oxide gives up its oxygen; the oxides
which give up their oxygen most readily yield the most ozone.

Again, every one knows that by decomposing the bioxide of barytes at the
ordinary temperature by the action of sulphuric acid, M. Houzeau has obtained
ozone in great quantity. It is known, since chemistry has existed as a science,
how much the nascent state of a body influences the combinations which it
is capable of effecting ; one combination is possible on/y when one of the bodies
which enter into it is in the nascent state; another only when the two bodies
which form it are in that state. What is called ‘nascent state”’ is, m my view,
nothing else but the allotropic state of the bodies entering into combination; an
opinion which I long since made public, and in which M. Houzeau seems to
concur with me.

From all these facts it appears incontestable that 7m every case in which oxygen
enters into combination or abandons its combinations it is in the state of ozone.
If, then, we reflect on the results already obtained with hydrogen, chlorine,
bromine, sulphur, phosphorus, &c., we shall be led to the conclusion that it must
probably be the same with all simple bodies; that is to say, that all these bodies
may assume an allotropic state analogous to ozone; that they are in that state
at the moment of entering into combination, or when they are in the “nascent
state.” ;

When a body in this allotropic state is isolated, as, for example, ozone pre-
pared by sulphuric acid and the bioxide of barytes, or in any other manner, we
may observe that it passes by degrees, and in a very short time, to its ordinary
state; and this is as it should be, for this body has necessarily a tendency to the
state of equilibrium which is observed in all parts of nature. We have said
that ozone is an allotropic state of oxygen; it is sometimes called “electrified
oxygen.”’* As has been shown, it is oxygen whose polarity is developed in the
highest possible degree. When ozone is produced, it is as though we took a
molecule of oxygen in a neutral electric state and‘deprived it more or less com-
pletely of its positive fluid. It is clear that this molecule will constantly tend
to reabsorb this lost fluid, that it may return to its natural state of equilibrium.
This is the reason why the stability of bodies in this state is so slight.

We have noticed the influence exerted on the polarity of bodies by electricity.
The action of ight, in this respect, is not less manifest. The properties of
chlorine exposed to diffused light, and of chlorine exposed to the solar light,

D
constitute a striking example of what has just been said. Besides, many of the

oD

phenomena before spoken of, are best produced under the influence of light. To
what extent /eat operates in the development of polarity has been known
since it was observed that certain combinations, which could not. be effected at
the ordinary temperature, are successfully brought about when the temperature
of the reacting bodies is raised. To cite one example, which will be suf-
ficient; when we have a mixture of oxygen and hydrogen in a_ glass
receiver at the ordinary temperature, these gases will not combine; but if
the mixture be heated, combination takes place immediately, because the heat
develops the polarity of the two gases. But how do heat, light, and electricity
develop polarity? 'This question we shall answer hereafter. The contact of
a third body, not susceptible of combining with one or other of the two reacting
bodies, is another condition which greatly modifies the polarity of bodies. ‘This
third body acts by its presence like heat, electricity, &c., in the development
of polarity. Berzelius thought he had detected in these phenomena of contact
the existence of a new force, which he called catalytic force, but in reality there
is nothing here but a phenomenon of polarity, as will be presently shown.

*Tt is thus designated by M. Scoutteten in his treatise on ozone, which name, however, is
erroneous.

STUDIES ON THE PHENOMENA OF CONTACT. AOL

Among the phenomena commonly designated by the term phenomena of con-
tact or catalytic phenomena, we muy mention, as one of the most remarkable,
the discovery in 1817, by Sir H. Davy, that a wire of platina will continue
incandescent in certain gaseous mixtures. He observed, in this manner, the
slow combustion of alcohol, of ether, of spirits of turpentine, of the oil of naphtha,
of earburetted hydrogen, &c. He found, still later, that palladium possessed
the same property. Some years afterwards, M. Doeberciner invented his hydro-
gen light apparatus, in which he employed spongy platina, and nearly at the
same time '[henard observed the curious and apparently inexplicable phenomena
which are exhibited when orygenated water is added to certain oxides, such as
the oxide of silver, &e. Dulong and Thenard subsequently studied the cata-
lytic influence of palladium, (previously noticed by Davy.) of rhodium, of iri-
dium, of gold, of silver, of nickel, and even of substances of a different nature,
such as charcoal, pumice-stone, porcelain, glass, and rock crystal. Still later,
Th. de Saussure announced that certain organic bodies, such as humus compost,
wheat, cotton, silk, and lignine, possess properties analogous to those of the
bodies previously named. He observed that these bodies effect a diminution
of volume in a mixture of oxygen and hydrogen, and that the volume which
disappears is in the proportion requisite to form water. MM. Mitscherlich,
Faraday, Reinsch, Boettger, Millon, and others, have still further enlarged the
field of catalytic phenomena. According to M. Reinsch, fibres of asbestos, when
gilded or plated, exhibit all the phenomena which have been remarked with
wire of platina or palladium, and it is nearly the same if these fibres be covered
with iron, nickel, cobalt, or lead. M. Beettger thinks that it is not always the
metal, but often its oxide, which is the active body in these latter cases. He
covered fibres of asbestos with oxide by plunging them in the solution of a
metallic salt, then in ammonia, whence they were rapidly passed through boiling
water, and were heated to redness ia the flame of an alcohol lamp. It results,
then, that the oxides of chromium, iron, nickel, maganese, &c., act like the
platina wire of Davy. One of the last labors of the illustrious Thenard proved
that in the case of any bedy whatever capable of disengaging a gas by heat,
such disengagement always takes place at a lower temperature when a third
body, a metal, an oxide, &c., is added, although we are sure that this third body
takes no part in the reaction. ‘The presence of .chips of beech-wood in the
manufacture of vinegar is another cxample of the phenomena with which we
are engiged. Yeast and the cognate bodies may be placed in the same class.

In all these instances it is chemical changes which are in question; the
combinations and decompositions of bodics. But contact may sometimes deter-
mine changes exclusively physical; as, for example, in the sudden ecrystalliza-
tion of a saturated solution of sulphate of soda by the contact of a slip of glass.
In 1855 I discovered that certain salts might effect the same molecular change
on the phosphorus which Weehlor had observed in fusing ordinary phosphorus
in a mixture of sulphuric acid and bichromate of potassa. These are salts
whose cold solutions phosphorus does not decompose, or at least decomposes but
slowly. ‘The following is what I stated at that time: “ It is a very remarkable
fact that certain salts, whose cold solutions phosphorus does not decompose,
appear to excrt a pecw iar action ou it, causing it to undergo a molecular modifi-
cation. Ifa portion of opaque reddish pho:phorus be placed in nitrate of iron,
dilated by about once its own volume of water, no chemical action is remarked
even after a long space of time. If the whole be then heated until the complete
fusion of the phosphorus is effected, and the tube with which we operate be then
removed to a quiet place, the phosphorus will remain liquid a long time, and
on decanting the liquor, will suddenly become solid, resembling, in all respects, a
globule of melted glass. In decanting the salt after cooling, the liquid phosphorus
will sometmes flow off with the solution. If after receiving the whole on filtering
paper, we touch this liquid phosphorus with a rod of glass, it suddenly be-

26s

~A02 STUDIES ON THE PHENOMENA OF CONTACT.

comes solid, and without any sensible change of volume. With a magnifying
class, it is easy to see that no trace of crystallization exists in the globule. It
is a limpid drop, and colorless as melted glass. By experimenting in different
ways, I ascertained that this limpid phosphorus differs, as regards its chemical
properties, in no respect from ordinary phosphorus. It does not, however,
take fire when poured out in a still liquid state in contact with the air. This,
then, is pot an allotropic state of phosphorus analogous to ozone, but a molecular
state peeuliar to this body. I have satisfied myself that other salts may act on
phosphorus like the nitrate of iron. If this colorless phosphorus be melted
under water and then exposed to the light, it reverts to the state of ordinary
opaque yellow phosphorus.”

Other examples of physical changes, analogous to those just mentioned, are
furnished by sublimation of the black sulphuret of mercury, which, by this
treatment, becomes red, by the red and yellow iodides of mercury; and since
in nature all phenomena are linked with one another, these two categories of
facts, to wit: the chemical and the purely physical changes induced by contact,
are connected by the phenomena of the explosion of different fulminating pow-
ders by mere contact with the barbs of a feather.

But these two last classes of facts stand somewhat apart from the domain
of catalytic phenomena, inasmuch as they are regarded as chemical phenomena.
Thus my experiments have taught me that phosphorus assumes the limpid and
colorless state whenever its refrigeration, after fusion, takes place under the
prescribed conditions, whatever may be the liquid with which we operate. It
is a phenomenon exclusively physical. If certain saline solutions cause it to
pass into this colorless and limpid state, it is because the phosphorus melted
in these solutions can cool more regularly than in pure water, and because such
cooling allows the molecules of phosphorus to arrange themselves in a position
suited to transmit the light entirely without reflecting or dispersing it. ‘The
black and opaque modification of phosphorus, diseovered by Thenard, is an anal-
ogous though inverted example of a molecular change.

An analogous ease is presented in fibrous iron, when it is made to undergo
frequent and prolonged vibrations. ‘There is established in the mass, ac-
cording to Pelouze, Liebig, and others, a molecular movement which occa-
sions the crystallization of the metal; so that it is not rare to see a bar of iron
of good quality slowly transformed under the influence of the vibrations into
iron crystallized with large facets.

Phenomena of this sort belong, as we have seen, to the domain of physics,
and have nothing in common with eatalytie phenomena. Another order of
facts, which more nearly approaches the latter, appears in the case of certain
oxides, which, when submitted to a certain degree of heat, become perfectly
indifferent in regard to reagents, giving place toa sort of phosphorescence.
They are then no longer dissolved in acids, or if so, are acted upon with much diffi-
culty. This may be referable to a loss of water, sustained by the calcination
of these oxides, but it is more probable that these phenomena of indifference are
analogous, but inverse to what is presented by oxygen when it passes into the
state of ozone.

The passivity of iron, of cobalt, and of nickel—three of the most magnetic
metals—appears due, according to recent experiments, to a slight layer of
oxide, or another combination which forms suddenly on the surface of the pol-
ished metal, and preserves it from the contact of the acid. From some trials
which I have lately made, but which are not complete, I am led to believe that
other metals may show the same property in certain conditions.

Let us pass to the examination of what occurs in catalytic phenomena,
properly so called, and let us take as a first example and type the combination
of hydrogen and of oxygen under the influence of the presence of platina. This
phenomenon is sometimes known under the name of slow combustion, a term

STUDIES ON THE PHENOMENA OF CONTACT. 403

which serves to designate, at the same time, a great number of like facts. Davy
sought to explain the slow combustions which he had observed by saying :
“Platina and palladium conduct heat badly, being of feeble capacities in com-
parison with other metals; and in this, it seems to me, resides the principal
cause why they maintain, produce, and render sensible these slow combustions.’’
But we have seen that sundry other bodies act in the same manner as the wire
of platina and palladium, when they are placed in the same conditions. M.
Dibereiner, on the contrary, regarded the combustion of hydrogen by the influ-
ence of platina as ‘an electric effect resulting from a circuit in which hydro-
gen represents the zinc and the platina the other metal. It is the first example,”
he added, ‘of an electric circuit formed of a gaseous substance with a concrete
body, whose activity has been verified.’’ Since then, Grove, in England, has
constructed his gaseous battery, of which we shall speak directly. Berzelius
imagines a new force generated in the contact of this third body, (platina;) a force
which he calls the catalytic, but of which he establishes no property unless it
be that of causing the two bodies to combine which, before the contact of the
third did not react. The influence which this great man exercised in chemistry
has caused his theory to be blindly adopted by many chemists. Nevertheless,
in proportion as catalytic phenomena became more common, as they began to
acquire the features of generalization, doubts respecting the existence of this
new force sprang up. And we shall endeavor, presently, to prove that this is
not only a gratuitous hypothesis, but that, with the knowledge even then
possessed regarding chemical combination, there was no need of supposing, for
an instant, its existence. Doebereiner was, it seems to us, much nearer the
truth than Berzelius, and this great chemist himself was subsequently led to
regard the phenomena of the catalytic force as electrical.

Let us return now to the combination of hydrogen and oxygen under the
influence of platina; and, to render things more evident, let us suppose for an
instant that we have a molecule of hydrogen, A, and a molecule of oxygen, B,
covered with neutral fluid. When we place these molecules in contact at the
ordinary temperature, they will remain neutral; we shall observe neither chem-
ical phenomena, nor electrical phenomena. But let them be heated; polarity
manifests itself, combination takes place, and the needle of a galvanometer will
sutliciently attest what is passing. By the action of the heat the two molecules,
A and Bb, become the one positive, the other negative, in relation to one another.
At the instant when the combination takes place the hydrogen gives off the
negative fluid, the oxygen the positive fluid, and these two fluids passing
into the wires of the galvanometer move the magnetic needle. ‘There are
here, then, two neutralizations of fluids; one in ¢he water, formed by the com-
bination ; the other by the fluids given off.

.This phenomenon which we have just been examining is the type of what is
called combustion. Now, what heat has effected in this case the presence of a
third body may likewise effect. This third body has the power, by its presence
alone, of exciting “combustion” at a temperature much lower than that which
as necessary for the production of this phenomenon when this third body is not
present. It effects this by a phenomenon of polarity identical with that which
ws observed in every other chemical reaction.

Before proving this by experiment, I shall show, with the help of a small
diagram, what passes under these circumstances. Let us imagine the three
bodies, hydrogen, oxygen, and platina sponge, in presence of each other:

404 STUDIES ON THE PHENOMENA OF CONTACT.

i Fig. 3. The polarity which was developed between the hy-
Lyra drogen and oxygen by the action of heat is now

iat f developed between these by the presence of the
+) S-seeL f ee platina. The xegative electricity of the hydrogen

tends to combine with the positive fluid of the platina,
while the positive electricity of the oxygen tends to
unite with the negative fluid of the metal. The

ie:
Y

(i) Pe a8 oxygen and hydrogen become thus negative and
BN positive in relation to one another, and can, conse-
Ox. quently, unite. Thus the two gases combine in

neutralizing their proper electricities. When, in place of using a simple wire
of platina, we augment the surface of the latter by employing what is called the
sponge of platina, the action is much more intense. In this case the platina
becomes incandescent in consequence of the electric action exerted on the sur-
face of that metal, and the heat developed is such that the hydrogen is eventu-
ally kindled.
I shall doubtless be asked if it is possible to prove, by Fig. 4.

direct experiment, that these phenomena really take place,

and if we have not here, also, an hypothesis or gratuitous ap:
supposition. I shall proceed at once to support by experi- (re
ment what I have just advanced, having only wished, in wi

order to make myself more clear, to indicate the theory
first and enter upon the facts afterwards :

Take two tubes of glass, one containing oxygen, the other hydrogen gas,
and place them upon water which is acidified with a drop of sulphuric acid to
make it a better conductor. Let there be then introduced into each tube a
strip of platina, so that it shall be plunged in the gas of the respectiye tubes
and be then bent back under the water in order to project from the surface of
the liquid. So long as the two strips of platina thus disposed remain separated,
we shall realize nothing; but let them be united by a galvanic multiplier, and
there will instantly be perceived on the magnetic needle the action of the current
proceeding from the strips of platina. We have thus, therefore, created a voltaic
arrangement, by means of which we may produce all the effects which would be
yielded by an ordinary pile. Fifty of these elements united constitute the
celebrated gas battery of M. Grove, which is well known to all our
readers. When the slips of platina present to the gas in the tubes a small
surface, the action is feeble, and it inereases with the extent of the surface
of metal in contact with the gas. When this species of pile is exclusively em-
ployed in decomposing water, the volumes of the gases proceeding from
the decomposition and collected in the voltameter are, both for the hydrogen
and the oxygen, exactly equal to the sum of the volumes of these gases which
disappear in the tubes of the pile. In proportion as the work goes on, the
volumes of the gases in the tubes diminish; they are visibly absorbed, and the
volume of hydrogen which disappears is always double that of the oxygen.
We see the same process here as when we burn hydrogen by means of
oxygen, at the ordinary temperature, by the contact of the spongy platina.
Here, therefore, is one experiment in support of our assertions. Let us pass
to others:

If we place a small gauge, made of a tube from two to three millimetres in
diameter and filled with hydrogen gas, on a vessel containing a concentrated
solution of chloride of gold, at the end of some days, #f the temperature has not
sensibly varied, the level of the chloride in the interior of the tube is little dif-
ferent from what it was previously; but if a platina wire be introduced from
below into the gauge in such manner that it shall be in part immersed in the
hydrogen gas and in part immersed at its lower extremity in the solution of gold,
we see the gas diminish in volume in the interior, and even completely disap-

STUDIES ON THE PHENOMENA OF CONTACT. 405

pear, at the end of a certain time, if the platina wire ascends to the top of the
tube. At the same time that the hydrogen disappears metallic gold is precip-
itated on the portion of the platina wire which is immersed in the metallic
solution. In this experiment the hydrogen is burned by the chloride of gold,
instead of being burned by the oxygen, as in the previous experiment. ‘The
positive electricity of the platina unites with the negative electricity of the
hydrogen, and the negative fluid of the platina unites with the positive elec-
tricity of the salt. When the hydrogen reduces the latter, there are formed
chlorhydric acid and metallic gold. The same thing would take place if we
operated without the platina, but at a high temperature only, as has been already
observed in reference to hydrogen and oxygen alone; for heat, as well as the
presence of a third body, develops polarity.

We have here exactly the phenomena which are presented by the voltaic pile ;
in fact, a pile is composed of two different metals and of a liquid which ean act
on one of the metals. If we take water as the liquid, pure iron and pure copper
as the metals, and plunge the pure iron alone in the water, there is no action ;
but if weadd a third body—the copper—action exhibits itself, as the galvanometer
indicates, the iron is oxidized, and hydrogen is disengaged. Volta intro-
duced, from the beginning, three substances into the composition of his pile—
two metals and moistened cloth.

The following are additional experiments: Take a porous vessel and place it
in a glass. In the porous vessel put hydrochloric acid; in the glass, nitric
acid; then let a strip of gold be placed in each receptacle; so long as
the two strips remain separated there is no action; but, on bringing them
together, they are immediately attacked, and the gold in the hydrochloric acid
is dissolved; the nitric acid is at the same time deoxidized by the nascent
hydrogen conveyed through the sides of the porous vase, while an electric
current traverses the strips of gold.

Further, hydrochloric acid mixed with nitric acid does not act on the latter if
the two acids:are diluted; but if we add a third body, iron, copper, gold,
platina, &c., action commences instantly ; the chlorine is disengaged, the nitric
acid is deoxidized, and the metal combines with the chlorine.

It is known that zine oxidizes slowly in water, because it is an clectro-pos-
itive metal; the disengagement of hydrogen in this case is very slow at the
ordinary temperature—so slow as scarcely to be perceptible. But if a highly
electro-negative body, such as sulphuric acid, be added, the polarity of the
zine is augmented; it becomes so electro-positive that the hydrogen is driven
with violence from its combination, and the zinc becomes its substitute. Before
the addition of the acid the polarity of the zine was analogous to that of the
hydrogen; but after that addition the metal becomes much more electro-posi-
tive than the hydrogen. Here is a phenomenon of polarity identical with
that which takes place when a strip of platina is introduced into a deto-
nating mixture. The sulphuric acid here acts, in regard to the zine, as the
platina towards the hydrogen.

I shall here cursorily cite some circumstances in which the influence of the
presence of a third body makes itself felt in the most ordinary cases :

1. Pure iron in dry air is not attacked; in humid air it oxidizes.

2. Iron, in boiled water, (not aerated,) does not oxidize; in aerated water,
oxidizes.

3. The peroxide of manganese (MNO?) calcined in oxygen (or in air) does
not alter;* heated in presence of oxygen and a base, a manganate is formed,
(RO, MNO*)

4. When electric sparks are passed into a mixture of dry nitrogen and
oxygen, no reaction is observed; if the two gases are moistened, nitric acid is
formed.

If the temperature is very high, it loses oxygen.

406 STUDIES ON THE PHENOMENA OF CONTACT.

5. Sulphurous and hyponitrie acids, (SO?4+AZO*,) when dry, do not
react, but if water be added, we obtain (AZO*SO*?+ HOSO*) which constitutes
the crystals of the leaden chamber.

I would also call to mind that the action of agua regia on the metals, which
I have just cited, has been, for some time past, perfectly explained by
chemists, (especially by Professor Koene, of the University of Brussels,) and
all are nearly agreed as to the phenomena which present themselves when the
two acids (CLH and AZO*) are poured on a metal. Now, have we not, in this
case, exactly the same phenomena which are observed when we place spongy
platina in a mixture of oxygen and hydrogen gases ?

The following experiment, easy to repeat, is a type of many chemical
operations, and has not escaped being sometimes attributed to the “ catalytic
force:”? when dry chalk is placed in a gun barrel, open at the ends, and
heated, the chalk will yield its carbonic acid at a certain temperature, A.
But if, while being heated, a current of vapor of water be passed over the
chalk, it will yield its carbonic acid at another temperature, B, considerably
lower than the temperature A. The explanation of this fact is quite simple.
The vapor of water acts here by what is called in chemistry the zxfluence of the
mass. The water is a weak base; the chalk a very strong one; yet the
volatility of the carbonic acid by heat, joined to the influence which the
mass of water exercises, causes the carbonate to yield its acid in presence
of the water at a temperature much lower than that which is requisite to pro-
duce this phenomenon when the water is not present. It does not follow thence
that the water which has induced this phenomenon combines with the lime
produced. 'The vapor acts solely as the platina does in Davy’s experiment
of slow combustion.

Lf, in one of the preceding experiments, in which oxygen gas, hydrogen gas,
and platina have been brought into contact, we substitute vapor of alcohol for
the hydrogen, we shall observe a phenomenon identical with that which is
presented by the two simple gases. The alcohol will be burned like the
hydrogen. In place of water we shall have aldehyde as the product, and the
explanation of the phenomenon wil remain the same. There is, in effect, a de-
velopment of polarity between the three bodies, and a pile might be quite as
well constructed by replacing the hydrogen in the pile of Grove with vapor of
alcohol. Alcohol, which is alvays more or less electro-positive in relation to
oxygen, becomes, by the presence of the platina, much more electro-positive ;
the oxygen tends, thereby, to combine with it, and this tendency naturally
determines the formation of aldehyde and acetic acid. 'The same phenomenon
presents itself when other vapors are substituted for that of alcohol, such as
those of different essences or essential oils, of ether, oil of naphtha, &c.

In these circumstances, when in place of platina other metals or non-metallic
bodies are employed, it is often necessary, in order that the action should man-
ifest itself with all its intensity, to add the agency of heat, that the phenomenon
of polarity may manifest itself and the combinations take place. But, in all
cases, it will never be necessary to raise the temperature to so high a degree, in
order to produce these phenomena, as it would be without the presence of the
third body.

The presence of a third body may effect or facilitate decompositions, as
well as combinations, in accordance with the same law. . Thus, in a mixture of
nitrous acid gas and hydrogen, the former gas is decomposed under the influence
of the platina sponge. All the oxides of nitrogen in this case yield ammonia.
Tron, copper, gold, &c., have the property of decomposing ammonia, if a little
heat be applied: and, according to Davy, nitrous acid may be formed under
these circumstances, (the presence of a metal,) at the expense of cyanogen
and oxygen, whereas, in the same case, cyanogen and hydrogen give cyanuret
of ammonia.

STUDIES ON THE PHENOMENA OF CONTACT. A407

It may be asked why the spongy platina acts more efiiciently in phe-
nomena of contact than the wire of the same metal. It is because in proportion
as a body is divided its surface is increased, and we have before seen that in
the gas battery the action is so much the more intense as there is a greater
surface of the platina in contact with the gas. Hence it is that we have in
chemistry the general law, that the greater the division of bodies the better they
react. Now, platina sponge is platina extremely divided, that is to say, pre-
senting a very large surface. We further see the effect of division in the
inflammation of pyrophorus.

In the phenomena which we have been examining the presence of a fourth
body usually prevents the phenomenon of polarity from taking place, and con-
sequently destroys the influence of the third body. Thus “the presence of
carbonic acid, for example, in the case of oxygen and hydrogen, prevents their
combining through the presence of a metal. It is thus, too, that a drop of
essence, will prevent fermentation. The spongy platina condenses in its pores
from thirty to forty times its volume of ammoniacal gas. Now, in this state, it is
altogether unfit to effect the combination of oxygen and hydrogen, and the
platina does not recover this property so long as it contains ammonia. The
presence of a fourth body does not, however, always exercise this influence. It
is necessary that it should be a body suited to react with the others to place them
in a state of equilibrium. Thus the presence of a little nitrogen does not prevent
the combination or the slow combustion of hydrogen mixed with oxygen, under
the circumstances we are considering. It has been seen, from my experiments
cited above, that the presence of an acid (as a fourth body) prevents the produe-
tion of ozone in certain special cases.

In ordinary fermentation, namely, in that, which is occasioned in a solution
of sugar by /eaven, it has been shown by Gay Lussac that the presence or the
contact of air or of oxygen is an essential condition of the manifestation of the
phenomenon, but that a single particle of oxygen suffices to excite, by
leavening, the fermenfation of a great quantity of sugar. Now, we have e already
seen that organic bodies may act upon oxygen to transform it into ozone; that
is, may induce a phenomenon of polarity ; and, moreover, in the exper iments of
De Saussure, that organic bodies may cause the combination of hydrogen and
oxygen. We have already said that, in our opinion, fermentation commences
with a phenomenon of polarity; oxygen or the leaven (it matters not which, as
action is always equal to reaction,) acts here as the ee does in the mixture
of oxygen and hydrogen. Polarity once brought into play in the saccharine
solution, there is no reason why it should cease as long as there remains any
sugar. The facility with which oxygen, as we have seen, is transformed into
ozone by its contact with érganic Bodies, determines, from the very first, this
phenomenon of polarity. The ozone produced being negative and the leaven
positive, in relation to the gas, this oxygen tends to ‘combine with the leaven ;
the sugar is, as it were, placed between the two poles of a pile; it is therefore
divided into two other bodies, of which one is negative (CO,) and the other
positive (AEH.)

Fig. 5. The presence of a fourth body often
WPS a C prevents this phenomenon; thus, when
the alcohol produced becomes sufli-
ciently predominant, all action ceases,
and it is necessary constantly to re-
move this product, if we wish the fer-
mentation to continue for an indefinite
time.

It is probable that something anal-
ogous takes place when caseine con-
verts sugar of milk into lactic acid.

408 STUDIES ON THE PHENOMENA OF CONTACT.

It has quite lately been placed beyond doubt that there are three bodies
present in this phenomenon, to wit: oxygen, sugar of milk, and a peculiar fer-
ment. M. Pasteur, in effect, has recently isolated a body which he calls
laciic ferment, and which, in his opinion, is the principal cause of the lactic
fermentation. It is a gray and flocculent substance, which proceeds, without
doubt, from the caseine. ‘The lactic fermentation, therefore, would be altogether
analogous to the alcoholic fermentation but with another ferment.

With regard to the viscous and butyric fermentations, &e., I have nothing to
add to what is already known respecting these phenomena—which is very little.
Respecting eremacausis (the slow combustion of organic substances by oxygen
at the ordinary temperature) or putrefaction, we have already scen how it is
induced, and how it is always accompanied with the production of ozone.

It remains to speak now of: the action of acids on organic bodies, for, in this
action it has been often supposed that catalytic phenomena were distinguishable.
When an organic substance is treated with an acid it often happens that this
acid oxidizes it while it is itself decomposed, such being the case when sugar,
&c., is treated with azotic acid, sulphuric acid, &e. At other times the acid,
or a derivative of the acid, combines with the body, either after having oxidized
it or directly. We observe this when we treat cellulose with concentrated
nitric acid. At other times, again, the oxide of a radical compound is formed
in the action of the acid on the organie body, with which the deoxidized
acid combines, as may be seen when hyponitrie acid reacts on the oxides of
certain radical compounds which may become peroxidized, and themselves unite
in this state with the nitrous acid, giving rise to nitrites (RO+AZO*—RO?AZO*.)
In fine, when acids are added to organic bases, or to alcohols, there are formed
salts, or compound ethers, which are also salts. In these two cases the acid
replaces the water of the base or of the alcohol. 'There are, however, cases
where acids occasion a change of a wholly different kind, and give rise to products
which may be termed abnormal.

Such is the case where sulphuric acid acts on fecula or on cellulose producing
sugar. In this case the influence of contact has been seen, and many
chemists have suppesed that the sulphuric acid acts only by its presence, and
that the fecula combines with a certain quantity of water to produce sugar. It
is, however, not so; the action of sulphuric acid on starch or cellulose ap-
pears to be altogether analogous to the formation of ether by the action of
this same acid on alcohol. In this latter case there is, as we know, the formation
of an intermediary compound, sulpho-vinie acid, which, by the action of heat,
separates into ether and free sulphurie acid. Now, sulphuric acid forms with
starch or cellulose, an analogous compound, sulpho-lignic acid, which, like
sulpho-vinie acid, forms soluble salts with lime and barytes, and separates
by ebullition into sugar and free sulphuric acid. The sulpho-lignic acid can-
not be formed except at the ordinary temperature. If the temperature be raised
we obtain other products, sulphuric acid is then decomposed, and produces,
with the cellulose, &e., brown substances resembling humus.

The diastase of sprouted barley gives rise to the same phenomenon as the
sulphuric acid in the former case, namely, the production of glucose, but this
is accomplished in a different manner. According to all appearance the trans-
formation is here direct. There is no intermediate combination; but the cir-
cumstances of that remarkable modification which the starch undergoes from
contact with the diaftase are still very incompletely known. It would seem,
however, that the diastase acts as a ferment, (as the ferment, for example, in
the aleoholie fermentation ;) and M. Magendie has observed in this connexion
that blood, bile, urine, sperm, &c., in a word, the other ferments act like
the diastase. Starch, in these circumstances, is first transformed into dextrine,
then into glucose. It is highly probable that hereafter it will be discovered
that the presence of a third body is essential to this phenomenon, and that

STUDIES ON THE PHENOMENA OF CONTACT. 409

this last being better understood, will be susceptible of the same explanation
as, chemical reactions in general.

It remains to examine the effects produced by the oxygenated water of
Thenard, and which are usually regarded as catalytic phenomena.

Oxygenated water is one of the most electro-negative bodies known ; hence
it acts in all cases as an oxidizing and energetic acid. When placed in con-
tact with the powder of platina a lively effervescence is observed, the platina
is not altered, all the oxygen of the oxygenated water is disengaged, and we
obtain water, pure oxygen, and pure metal. This reaction is precisely what
was to be expected: in effect the oxygenated water acts towards the platina
as.an acid; it tends to oxidize the metal, that is to say, in this phonomenon
the platina is electro-positive, the oxygenated water eleciro-negative. The
platina tends to form a peroxide, but this oxide not being susceptible of being
formed under these circumstances, the phenomenon of polarity takes place
nevertheless, and the oxygen is disengaged.

The same thing occurs if we treat comminuted platina with nitric acid. This
acid, which is an energetic oxidant, like oxygenated ‘water, is decomposed
ata temperature much lower than if the platina were not present. I have
observed lately that this phenomenon takes place with certain sulphurets, es-
pecially with certain specimens of sulphuret of copper from the environs of
Lake Baikal, in Siberia, which were sent to me for analysis. If we take
this sulphuret of copper, calcined and dry, and in a state of great division pour
upon it concentrated nitric acid, and then heat with an alcohol lamp, the
nitric acid is decomposed, and gives forth ruddy vapors, without attacking the
sulphuret, and at a temperature much inferior to that at which nitric acid is
decomposed by heat alone. If we would transform the sulphurct into a sulphate
we must not operate in this manner, as we lose the acid without obtaining the
desired effect. In order to oxidize the sulphuret we must add the acid drop
by drop whilst we are applying heat; the sulphuret is then actively attacked.

Molybdenum, treated with oxygenated water, passes, on the contrary, to the
acid state, as is the case also with arsenic, selenium, &c., while silver, gold,
mercury, palladium, rhodium, &c., &c., act in these circumstances like platina.

Tn this action of platina and of metals in general, on oxygenated water, an
extreme tenuity in the metal is an indispensable condition for obtaining a
prompt reaction. ‘This has been equally indicated in speaking of the action of
divided platina, and it is the same in every chemical reaction, whatever it
may be.

The oxides which can be oxidized, (Ca’, Ba’, Ca’, &c.,) decompose
oxygenated water in passing to the state of peroxides, (Cd, Ba, Cd, &c.) The
oxides which cannot be oxidized may sometimes effect the decomposition
of oxygenated water, because they are highly electro-positive in regard to it,
and the phenomenon of polarity takes place. 'The peroxide of manganese, for
example, cannot be oxidized, except in contact with a base with which
the manganic acid produced may combine. When this peroxide is added to
oxygenated water, manganic acid cannot be formed; but oxygenated water,
being a body but slightly stable and highly electro-negative in regard to Mn,
reacts on this peroxide and tends to oxidize it. ‘The peroxide of manganese is
then in the same situation with platina, silver, &e., cited above. .

The presence of a third body in phenomena of contact does not act solely
by exciting a phenomenon of polarity, which, without the presence of the third
body, would not occur, unless brought about by a high temperature. It often
exercises, besides, a very marked influence on the products of the reaction,
especially if we operate. on organic bodies; thus: Take two small tubular
retorts of the same capacity, and place in the one tartaric acid, in the other
tartaric acid and platina sponge; then let the two retorts be heated at the
same temperature, which is easily done by placing both in the same sand-bath.

410 STUDIES ON THE PHENOMENA OF CONTACT

The first retort will, in these circumstances, yield gases and the ordinary em-
pyreumatic products. The other, on the contrary, will give crystallized pro-
ducts. ‘This, however, is but one example in a thousand. In one case the
reaction is more ready than in the other, consequently the products should be
different. A body susceptible of yielding a gas by the action of heat will
yield this gas at a temperature much lower—that is, more easily, when it is
mixed with another body which cannot combine with any of the elements
submitted to experiment.

Supposing that we submit to the action of heat a dinary body to which we
add a third element; whether this third body combines with one of the elements
of the binary body, or does not so combine, its presence will always facilitate
the reaction which takes place, by the development of polarity in which this
third body bears a part.

That the exact knowledge of the modes of action of a third body may be-
come of great utility to the chemist the following example, familiar to all, will
show. ‘lo procure oxygen by means of the chlorate of potassa, we shall
economize combustible matter by introducing a body foreign to the reaction,
for instance, clippings of platina, sand, peroxide of manganese, &c., &c.

It is some years since M. Millon remarked, that. zine dissolves much
more rapidly, and produces at the same time much more hydrogen, when a
metal less electro-positive is added to the sulphuric acid. This is the type of
catalytic phenomena in general. A little of the chloride of platinum, mixed
with the sulphuric acid, gives rise to a disengagement of hydrogen one
hundred and fifty times stronger than that which the same surface of zine would
produce in the pure acid, of the same degree of concentration, and in the same
time. ‘This experiment is, as we see, a simple modification of another well
known one, which consists in surrounding the zine with a wire of platina to
accelerate the solution; for the platinum of the chloride is precipitated on the
zinc, and forms with it a voltaic element.

Hydrochloric acid mixed with a little chloride of platinum dissolves lead and
copper with a disengagement of hydrogen. The first dissolves it in this way
when cold, the second only when heated, but the disengagement is as rapid
with the zine.

Before concluding this memoir, we should endeavor to compare the relations
of the phenomenon of polarity, with what is called chemical affinity. And in
the first place, when we speak of polarity, we express a fact verified by ex-
periment—a fact which has nothing in common with the so-called ‘catalytic
force,” of which it 1s impossible to verify a single property. Livery chemist
knows that the phenomenon of polarity manifests itself in every chemical
reaction. We have shown in the present paper that it manifests itself equally
in catalytic phenomena. We verify polarity by direct experiment, as has been
shown. ‘This, then, is not a word exchanged for the word catalysis, but is a fact
well established.

We have already shown how much the phenomenon of polarity influences
chemical reaction. Is it the cause of affinity, or is affinity itself a force sud
generis? Berzelius remarked, in regard to the before-cited experiments of
Millon, “These experiments show clearly that the greater or less affinity of the
acid for the metal, and, reciprocally, is due to the more electro-positive state.
which results from the contact of the metal deposited; and that it is this state
which induces the affinity, but not inversely the affinity which induces the
electric state.’ In effect, one party thinks electricity or polarity produces
chemical action, while another supposes that all electricity is produced by
chemical action. Hither explanation is simply absurd. Experiment shows
that the phenomenon of polarity is an electrical phenomenon if you choose—
accompanies chemical action everywhere; but we cannot thence conclude that

STUDIES ON THE PHENOMENA OF CONTACT. All

it is the cause of the latter, just as we sometimes sce electricity excited, without
being able to assign to this electricity a chemical origin.

We may say that in every case, without exception, an electric current may
determine the combination or the decomposition of bodies, and polarity seems
to be an indispensable condition, in order that chemical action should manifest
itself. Chemical aftinity cannot be regarded as the cause of the polarity ;
polarity cannot be regarded as the cause of the affinity. When, in heating a
plate of bismuth soldered to a plate of antimony, electricity is produced,
what is the cause of its production? Is it in the affinity of the bismuth for
the antimony? Certainly not! Is it in the heat? We enter here upon con-
siderations of a very high order, and which it is not competent for us to discuss
on this occasion. Let us say, however, a few words respecting them.

In all that has been said, we have employed the term force. Although
it be now nearly demonstrated that nearly all force is but a molecular move-
ment, and that, consequently, the idea which we generally attach to the word
force is inexact, yet the epoch has not arrived when we can suppress these
terms in the language of science, and, at the same time, make ourselves intel-
ligible. I have thus found myself compelled to employ them. In the remark-
able theory of M. Grove on the correlation of physical forces, things are
considered, according to all probability and verisimilitude, under their true
point of view. Movement, which is universal, manifests itself to us sometimes
under one form, sometimes under another, in order to give rise to effects which
we are in the habit of attributing to particular forces. These forces, or, rather,
these movements, may be transformed into other equivalent movements,
according to the circumstances in which they are made to act. Thus it
is that if We apply friction (movement) to a piece of dry wood, it is transformed
into another movement which we call heat. If we apply friction to sealing-wax,
the friction (movement) is transformed into current electricity. If we heat
water a large quantity of the heat is transformed into a motive force, into
movement. If we heat a plate of bismuth soldered to a plate of antimony, the
heat is transformed into current electricity. In like manner, heat is transformed
into light, light into heat, into electricity, into affinity, &c.; affinity into heat, into
electricity, into light, &c., &c. There exists no ‘“foree’” which we cannot
transform, equivalent for equivalent, into one or several other “forces.” - These
transformations are manifested throughout all nature, and we see what we call
“physical and chemical forces” transformed into ‘organic forces,” and gov-
erning the phenomena of life. Just as atoms combine or replace one another
by equivalents, so are different movements or “forces”? substituted, one for
another, equivalent for equivalent. A given quantity of chemical action will
always give the same quantity of electricity; a given quantity of electricity
will, in its turn, give the same quantity of chemical action; a given quantity
of heat will always give the same quantity of motive force; an equivalent of
chemical action will always give an equivalent of heat, &e., &e.

In fine, everything is connected or linked together in nature; move-
ment, like matter, is universal; its modifications produce all that we regard as
“forces”’ or effects of forces. For the details and experiments on which this
striking theory is based, (and it is now admitted by most physicists,) we must
refer our readers to the memoir of M. Grove,* of which we have a French
translation from the learned pen of M. I’. Moigno. But, from the few words
which have been said, it will, I think, be conceived how heat can act to excite
polarity and chemical action; how the latter, in its turn, can excite polarity and
heat, without one of these forces” being the cause, properly speaking, of the
other; how the movement of the barbs of a quill can act so as to produce
explosion with fulminating powders, &c.

*Correlation of physical forces.

412 STUDIES ON THE PHENOMENA OF CONTACT.

CONCLUSION AND CONCLUSIONS,

Although many of the experiments cited in this memoir are my own, and
others have been repeated and confirmed by myself on more than one occasion,
I could have wished, nevertheless; to have added more in confirmation of the
views which I have enunciated on the phenomena of contact. For, however
conclusive the experiments cited may seem to myself, it is not certain that they
will appear so to every one. But two things essential to all scientific research
fail me at this moment, and prevent me even from completing researches already
commenced. or what concerns the present attempt, I trust that it has been
demonstrated to a certain point :

I. That the allotropic states of bodies, analogous to ozone, are dne to a
phenomenon of polarity acting in special circumstances, and having the effect,
of rendering the body, which is the subject of experiment, much more
electro-negative, or more clectro-positive, than it was; and that the state which
we call in chemistry the “nascent state of bodies” is nothing else but this
allotropic state. Further, that all simple or compound bodies assume this
state at the moment when they enter into combination, and at the moment
when they abandon their combinations.

Il. That in general the phenomena attributed to the catalytic force, as well
as those which every other chemical reaction presents, admits of a very simple
explanation.

III. That the facts observed and explained by the action of a force called
force of contact, or catalytic force, are due to an electro-chemical phenomenon,
known under the name of polarity, which, without being the cause of the
chemical action, accompanies the latter in all cases, may be verified by direct
experiment, and seems to be an essential condition of its manifestation.

ITV. That the foree known under the names of catalysis, force of contact,
or catalytic force, is a pure creation of the imagination.

see ON ATOMS. . 445

ON ATOMS.

BY SIR JOHN HERSCHEL.

“Tsing of atoms.”—Rejected Addresses.

Di1aLoGur.—Hermogenes et Hermione interloquuntur.

HHernione.—W hat strange people those Greeks were! I was reading this morn-
ing ahout Democritus,“who first taught the doctrine of atoms anda vacuum.” [
suppose he must have meant that there is such a thing as utterly empty space,
and that-here and there, scattered through it, are things called atoms, like dust
in the air. But then I thought, “What are these atoms?” for if this be true,
then, these are all the world, and the rest is—nothing !

Hermogenes—Yes. That is the natural conclusion: unless there be some-
thing that does not need space to exist in; or unless there be things that are not
material substances ; or unless space itself be a thing : all which is deep meta
physic, such as I am just now rather inclined to eschew. But, dear Hermione,
how am I to answer such a host of questions as you seem to have raised—all
ina breath? The Greeks! Yes, they were a strange people—so ingenious, so
excursive, yet so self-fettered; so vague in their notions of things, yet so
rigidly definite in their forms of expressing them. Extremes met in them. Tn
their philosophy they grovelled in the dust of words and phrases, till, suddenly,
out of their utter confusion, a bound launched them into a new sphere. ‘There
is a creature, a very humble and a very troublesome one, which reminds me of
the Greek mind. You might know it for a good while as only a fidgety, rest-
less, and rather aggressive companion, when, behold, hop! and it is away far
off, having realized at one spring a new arena and a new experience.

Fermione—Don’t! But a truce to the Greck mind with its narrow pedantry
and its boundless excursiveness. ‘The excursiveness was innate, the pedantry
superinduced—the result of their perpetual rhetorical conflicts and literary com-
petitions. I have read the fifth book of [uclid and something of Aristotle ; so
you need not talk to me on that theme. Do tell me something about these
atoms. I declare it has quite excited me, ’specially because it seems to have
something to do with the atomic theory of Dalton.

fHermogenes.—Higgins, if you please. But the thing, as you say, is as old as
Democritus, or perhaps older; for Leucippus, Democritus’s master, is said to
have taught it to him. Nay, there is an older authority still, in the personage
(as near to an abstraction as a traditional human being can be) Moschus (not he
of the Idyls.) But the fact is that the notion of run atrom—the cndivisible,
“the thing that has place, being, and power—is an absolute necessity of the
human thinking mind, and is of all ages and nations. It underlies all our
notions of being, and starts up, per se, whenever we come to look closely at the
intimate objective nature of things, as much as space and time do in the subjec-
tive. You have dabbled in German metaphysics, and know the distinction I
refer to.

ermione.—You don’t mean to say that we are nothing but aroms !—Place!
being! power! Why, that is I, it is you, it is all of us. Nay, nay. This is
going too fast.

414 ON ATOMS.

Hermogenes.—Perhaps it is—(You have forgot thought, by-the-by, and will.)
But I am not going to make a single hop quite so far. We shall divide that
into two or three jumps, and loiter a little in the intermediate resting-places.
But, to go back to your atoms and a vacuum. What does a vacuum mean ?

Hermione.—Vacuum? Why, emptiness, to be sure! I mean empty space.
Space where xo thing is. I am not so very sure that I can realize that notion.
It is like the abstract idea of a lord mayor that Pope and Atterbury talk about;
and in getting rid of the man, the gold chain and the custard are apt to start wp
and vindicate their claim to a place in the world of ideas. And yet I do mean
something by empty space.. I mean distance—I mean direction : that steeple is
a mile off, and not here where we sit; and it lies southeast of us, and not north
or west. And if the steeple were away, I should have just as clear a notion of
its place as if I saw it there. There now! But then distance and direction
imply two places. So there are three things anyhow that belong to a vacuum;
and let me tell you, it is not everything that three things positively intelligible
can be “predicated” of (to speak your jargon.)

Hermogenes— Dear me, Hermione! how can you twit me so? Jargon!
Every specialty has its “jargon.” Even the law, that system of dreams, has
its “jargon’’—the more so, to be sure, because it 2s a system of dreams, or
rather of nightmares, (God forgive me for saying so!) Well, then, you seem
to have tolerably clear notions about a vacuum—at, least, I cannot make them
clearer. Much clearer, anyhow, than Descartes had, who maintained that if
it were not for the foot-rule between them, the two ends of it would be in the
same place. Still, there is much to be said about that same Vacwum, especially
when contrasted with a Plenum, which means (if it mean anything) the exact
opposite of a vacuum. In other words, a “jam,” a “block,” a “fix.” But, on
the whole, I lean toa vacuum. The other ideais oppressive. It does not allow
one to breathe, There is no elbow-room. It seems to realize the notion of that
great luman squeeze in which we should be landed after a hundred generations
of unrestrained propagation.* One does not understand how anything could
get out of the way of anything else.

Hermione-—Do come back to our dear atoms. I love these atoms: the deli-
cate little creatures! There is something so fanciful, so fairy-like about them.

Hermogenes.—W ell; they have their idiosyncrasies. , 1 mean they obey the
laws of their being. They comport themselves according to their primary con-
stitution. ‘hey conform to the fixed rule implanted in them in the instant of
their creation. They act and react on each other according to the rigorously
exact, mathematically determinate relations laid down for them ad initio. ‘They
work out the preconceived scheme of the universe by their—their

Hermione —Their?t Stop, stop! my dear Hermogenes. Where will you
land us? Obey laws! Do they know them? Can they remember them?
How else can they obey them? Comport themselves according to their primary
constitution! Well, that is so far intelligible: they are as they are, and not as
they are not. Conform to a fixed rule! But then they must be able to apply
the rule as the case arises. Act and react according to determinate relations !
I suppose you mean relations with each other. But how are they to know those
relations? Here is your atom A, there is your atom B, (I speak as you have
taught me to speak,) and a long interval between them, and no link of connection.

* For the benefit of those who discuss the subjects of Population, War, Pestilence, I’amine,
&c.. it may be as well to mention that the number of human beings living at the end of the
hundredth generation, commencing from a single pair, doubling at each generation, (say in
thirty years, ) and allowing for each man, woman, and child an average space of four feet in
height, and one foot square, would form a vertical column, having for its base the whole sur-
face of the earth and sea spread out into a plane, and for its height 3,674 times the sun’s dis-
tance fromd¢he earth! The number of human strata thus piled one on the other would amount
to 460,790,000,000,000.

ON ATOMS. 415

How is A to know where B is, or in what relation it stands to B? Poor dear
atoms! I pity them.

Hermogenes—You tay spare your sympathy. They are absolutely blind
and passive.

Hermione—Blind and passive! The more the wonder how they come to
perceive those same relations you talk about, and how they “comport them-
selves,” as you call it (act, as I should say) on that perception. I have a better
theory of the universe.

Hermogenes.—T ell it me.

Hermione.—In the beginning was the nebulous matter, or Akasch. Its bound-
jess and tumultuous waves heaved in chaotic wildness, and all was oxygen, and
hydrogen, and electricity. Such a state of things could not possibly continue ;
and as it could not possibly be worse, alteration was here synonymous with im-
provement. ‘Then came

Hermogenes—Now it is my turn to say, Stop! stop! Solvuntur risu tabule.
Do let us be serious. Remember, it was you who began the conversation. Je
me suis seulement laissé entrainer. The tact is, I have only so far been trying
you, and I see you are apt. There lies the real difficulty about these atoms.
These same “relations” in which they stand to one another are anything but
simple ones. They involve all the “ologies” and all the “ometries,” and in
these days we know something of what that implies. Their movements, their
interchanges, their “hates and loves,” their “attractions and repulsions,” their
“correlations,” their what not, are all determined on the very instant. There is
no hesitation, no blundering, no trial and error. A problem of dynamics which
would drive Lagrange mad, is solved ixstanter “Solvitur ambulando.” A difter-
ential equation which, algebraically written out, would belt the earth, is integra-
ted in an eye-twinkle ; and all the numerical calculation worked out in a way to
frighten Zerah Colburn, George Bidder, or Jedediah Buxton. In short, these
atoms are most wonderful little creatures.

Hermione—W onderful, indeed! Anyhow, they must have not only good
memories, but astonishing presence of mind, to be always ready to act, and
always ¢o act without mistake, according to “the primary laws of their being,”
in every complication that occurs.

Hermogenes—TVhou hast said it! That is just the point I knew you must
come to. The presence of MIND is what solves the whole difliculty ; so far at
least as it brings it within the sphere of our own consciousness, and into con-
formity with our own experience of what action is. We know nothing but as
itis conceivable to us from our own mental and bodily experience and conscious-
ness. When we know we act, we are also conscious of will and effort; and
action without will and effort is to us, constituted as we are, unrealizable, un-
knowable, inconceivable.

Alermione—Vhat will do. My head begins to turn round. But I hardly
fancied we had got on such an interesting train. We will talk of this again.
More to-morrow. Now to the feast of flowers the children are preparing.

416 ON THE CLASSIFICATION OF BOOKS.

ON THE CLASSIFICATION OF BOOKS.

BY Soe Ne eS
LIBRARIAN OF THE AMERICAN PHILOSOPHICAL SOCIETY.

Lisrarins are of two kinds, general and special. The one now catalogued* is
of the most general description, aud affords an opportunity for some thoroughly
philosophical arrangement, based upon an analysis of human knowledge which
will leave nothing disregarded. However imperfectly the attempt to accomplish
the object may succeed in this or other instances, failure will only stimulate to
renewed endeavor. A reasonable arrangement, of every collection in the hands
of man is a call of the soul, to be obeyed. A merely empirical adjustment of
minerals to the drawers which contain them, or of books to the shelves on which
they stand, fortuitously numbered as they are obtained, and indexed alphabeti-
eally for the convenience of servants, justly embarrasses, depresses, and disgusts
the thinker.

Two arrangements of a catalogue, systematic or raisonnée, present themselves
at once for selection: the analytic and the synthetic. The synthetic corresponds
with the teachings of nature and art, by the experience of which we are in-
structed in items to the knowledge of the whole. The analytic corresponds
with the method of the schools, and of their reliquix, books; which state prin-
ciples, and then describe their applications; announce laws, and then show their
utility; first furnish knowledge in its most advanced or abstract condition, and
afterwards embody it in illustrations. Face to face with nature, the form of
man receives its noblest zzspzration; but by libraries of books the spirit of man
obtains its largest zformation.

The book of nature and the book of the library being thus opposed, the one
is not consulted in the same manner as the other. The book of nature begins
with its illustrations, follows with descriptive text, sketches out indistinctly a
few broad statements, suggests. summary, and omits the index altogether.
The book of the library, on the contrary, carefully places its table of contents
in the front, makes of its preface’ an epitome, and of its body an argument,
leaving notes and pictures to be consulted, at the pleasure of the reader, at the
close. In these antagonistic gymuasia two antagonistic tribes are bred, mere
scholars and mere naturalists, characterized by opposite tendencies: by the loose-
ness with which the former state facts, and the pertinacity with which they
maintain doctrines; by the scrupulous narrowness with which the latter examine
things, and the facility with which they adopt new theories. To be a mere
scholar is to run the risk of becoming inaccurate in facts and dogmatic in
judgment. 'l’o be a mere naturalist is to become materialistic and unimaginative,
narrow-minded and pedantie.

The trne philosopher resides alternately in nature and in the library. Writing
in the first and reading in the second, he weaves shuttle-like the stuff of thought
out of which he and his fellows array themselves in goodness, truth, and beauty.
But of these two homes, the philosopher has two very different stories to tell;
he regards them with very different sentiments. The one is ancestral—he was
born into it and belongs to it; the other he makes proper to his hand. The:
_ philosopher must accept his rural residence as it grows, enclosing him with

* Library of the American Philosophical Society, Philadelphia

ON THE CLASSIFICATION OF BOOKS. AIT

powers of arrangement regardless of his will, yet amiably inviting his attention.
But his urban residence, the library, he arranges as the master of it, according
to his own convenience, to correspond with his own necessities and to illustrate
his tastes. The character of the library is therefore determined by the principles
of art, not nature.

The general library, therefore, is a picture of a generous intellect, well stored,
well ordered, and open to enlargement in all directions.

Its compartments represent the grand natural divisions of knowledge.

Its classification should be in an ascending and advancing series.

Its treasures, like those of memory, should be preserved in the natural order
of time, and the natural order of space should be ancillary and complementary,
wherever applicable.

These are the maxims by which the cataloguing of the library of the American
Philosophical Society has been governed. Hight principal classes carry from the
universal to the special, from the abstract to the concrete, from the inorganic to
the organic, and from matter to mind. Each class begins with the theory of its
subject and follows with its practice. Excepting the first, which represents the
abstract conception of knowledge itself with its universal applications, each
class advances the theme beyond a point at which the class preceding leaves it.
More scientific names might be invented for these classes, but only by having
recourse to a pseudo-classical, harsh, unknown compound terminology, and
therefore the names which have been adopted are those best known and in
common use, as follows:

1. GENERAL SCIENCE.
1. Encyclopedias, &e. 1°. Learned Societies. 15. Catalogues of Libraries.
2. THE MATHEMATICAL SCIENCES.
2. Mathematics. 27. Astronomy, &c. 2°. Geodesy, &c. 2*. Physics.
3. THE INORGANIC SCIENCES.
3. Chemistry. 3%. Mineralogy. 3°. Mining. 3%. Geology and Pal:contology.
4. THE ORGANIC SCIENCES.
4, Biology. 4*, Botany, &c. 4°. Zoology, &ce. 4*, Medicine, &e.
5. THE HISTORICAL SCIENCES.
5. Chronology. 5*. Ethnology. 5°. Archeology. 5+. History.
6. THE SOCIAL SCIENCES.
6. Sociology. 67. Manufactures. 6°. Commerce. 6%. War. 6°. Law.
7. THE SPIRITUAL SCIENCES.

7. Language 7*. Belles-Lettres. 7°. Fine Arts. 7, Logic, &e.
StS = : | Bra 2
7°. Education, &c. 7°. Religion.

8. PERSONAL SCIENCE.
8. Biography.

The divisions of the eight classes are naturally made by separating the pure
sciences from their applications, and by grouping the latter according to their
relationships. Thus the mathematical sciences are divided into—Mathematies
pure (2'); mathematics applied to astronomy (2”); mathematics applied to
geodesy (2%); mathematics applied to mechanics and physical questions gener-
ally (2*.)

27 8

418 ON THE CLASSIFICATION OF BOOKS.

It may be thought that this order ought to be reversed if the rule of an upward
advancing series be inflexible and absolute; and that the first application of
pure mathematics should be to physics or pure mechanics; the second to
geodesy; and the third to astronomy or celestial mechanics. But a little con-
sideration will teach that the first, most common and closest practical application
of pure mathematics has been to astronomy and navigation; then to geodesy ;
and then to the mechanic arts; whereas physics proper have been based hitherto
much more on experiment than on calculation. ‘he rule of an upward advane-
ing series is indefinite in one of its factors, if not in both; for questions of
dignity among the sciences are not always easy to settle; nor can astronomy
maintain so easily as onee she could her right to precedency at court before
geodesy, now that the personal characters of the planets and fixed stars have
been so critically discussed. The rule of common usage, therefore, which is
also the rule of convenience to some extent, must have some power given it
over these arrangements; especially where, as in the case in point, still further
subdivisions must be made to reach the last or most concrete applications of the
science pure. Astronomy is indissolubly connected with meteorology, and finds
its practical utility in navigation. Geodesy cannot be separated widely from
geography; while this last involves voyages and travels, and this again maps
and charts, which are the direct objects of geodesy. No less does the division
of physics create, if the library be extensive, the distinct sections of light,
heat, magnetism, electricity, &c.

But there is another reason for the order adopted. A third and most important
rule of arrangement remains to be stated. It will be seen that certain subjects
are essentially transitional, and must be placed at the end of the class to which
they belong, for the reason that they carry the train of development over to the
beginning of the class next following.

Thus, ine Class II, that of the mathematical sciences; division 2, that of
physies, stands last because the next Class III, that of the inorganic sciences,
begins with chemistry. In Class III, division 3*, geology comes last, because it
carries with it paleontology, mediating between the inorganic and the organic
world. In Class LV, division 4, human physiology comes last, because it
brings into view the close and consummation of the whole organic system,
man, and thereby prepares the way for historical research.

Leaving the first or natural series, and coming to the second or human series,
we find the same rule reigning. In Class V, that of the historical sciences
proper, which still regards mankind from a naturalistic point of view as inhab-
iting the earth like the other orders of created beings, but with peculiar and
hicher relationships to it, namely, the relationships of time, progress, de evelop-
ment, and accomplishments, and therefore commences with chronology, it is
plain that division 5‘, that of history proper, must follow ethnography and
archeology, instead of preceding them, because it alone can introduce the
discussion of society.

In Class VI, that of the social sciences, regarding mankind with still in-
creasing respect—no longer as a mere herd of intelligent animals spread abroad
at first, ‘and afterwards migrating to and fro upon the earth by virtue of cosmical
influences, and absolutely under their direction, but as groups of thoughtful
people, endowed with the genius of arts and arms, and skilled in manufactures,
commerce, war, and law, it is evident that these four applications of human
genius in society maintain the ascending movement, and pass us seriously from
fis over to the next. Legal science, de ision 6°, stands last in order, because
related nighest, through language, to the spiritual sciences, which occupy the
seventh plane.

In Class VU, its last division, 7°, that of religious science, ig not merely the
culmination of this particular class, considered as the range of man’s instincts ef

ON THE CLASSIFICATION OF BOOKS. 419

self-expression: language, belles-lettres, fine arts, rhetoric, logic, education,
and philanthropy; but is a worthy engrossment and presentation of all the
classes gone before, and the fittest introduction to Class VIII, biography, the
science of the individual man per se, of the microcosm, the summary and con-
clusion of knowledge, the return of the cirele into itself.

Regarded as divisions and subdivisions of human knowledge, it is very likel
that other minds consulting this catalogue will take a different view of the relative
value of these classes and divisions, and therefore of their respective claims to
the prominent places which they occupy. But there is not one of them that has
not been called and is not well recognized as a separate branch of science, having
societies specially founded for its investigation and text-books written for its
special elucidation. he list also seems complete. ‘There may be question of
the arrangement in certain parts, but the uninterrupted progression of the whole
will be allowed on the ground of the accepted hierarchy of the numerical, inor-
ganic, organic, mental, moral, and religious worlds. No argument can change
this order of sequence and dignity.

Certain exigencies of the librarian, nevertheless, or of the student, and certain
inosculations, interferences, or cross-relationships among the many members of
the corpus scientiarum, cause perplexity, and introduce an apparent element of
discord. But when the principal instances of its appearance have been mentioned,
they will be seen to cause no serious disturbance in the order of the whole, and
may be compared to those threads of shade which throw themselves across the
colors of the spectrum, only to suggest new revelations of the harmony which
reigns throughout the universe of light.

‘The following are the principal suggestions to be made in view of the practi-
eally abnormal occurrences to be expected in this arrangement of a library.

Class I. Under societies’ proceedings (1”) a complete list of learned societies,
whose publications are represented in any degree in the library, is given. But as
many of these societies devote their publications to special sciences, the detailed
description of their issues must appear under such special heads. In such an
immense collection of these issues as that now making by the Smithsonian Insti-
tution at Washington, it is found necessary to devote one entire hall of the library
to their reception, and, in fact, to organize a separate department of correspond-
ence. Even with smaller collections, this is by far the best arrangement for the
librarian. But for the student it is evidently more desirable to have the issues of
all botanical societies in the alcove devoted to botany, all those of medical socie-
ties in the aleove of medicine, all those of antiquarian societies in archeology,
those of historical societies in the cases of history, &e. But for the same reason
it is proper to classify the titles of their issues under corresponding heads in the
catalogue raisonnée. If, at the same time, the titles of all general societies and
references to the titles of all special societies be resumed under the division (1?)
of learned societies, a coup d@’ wil is obtained of the learned world. In some
few instances double entries must be made of so-called special societies, such as
those of natural history, the titles of which must be referred to under botany,
and under zoology also. But they are few in number.

Class II. Meteorology is a science with a literature of its own, and must
therefore have a place of its own; but its désjecta membra give much trouble,
and would be thrown by a close criticism into several divisions or subdivisions.
Its observations are almost always made in connexion with astronomy; some
of iis meteors are cosmical, and come under a sub-section of astronomy (2?");
others are atmospheric, and come under another sub-section of astronomy (2°);
others are of a so-called physical kind, and would come under magnetism, &c.,
(2*); others are mineralogical, and connected with geological phenomena, and
would come under 3° and 3%. It has been placed in this class and made a cor-
relative branch of its second division with astronomy, because of their practical
connexion in the observatory, and because of their literal connexion in the

420 ON THE CLASSIFICATION OF BOOKS.

proceedings and transactions of academies and societies. Magnetism would
follow it into the same position were it not for the fact that all the earlier
literature of magnetism is bound up with that of light, heat, and electricity,
and the other subjects of physics so called; and the only practical connexion
that it maintains with astronomy and meteorology, that of the observatory, is
not universal, and is not so close as that which it maintains with geodesy.

Navigation also is so connected with astronomy and meterology that it finds
its proper place with them. As a science it is not to be confounded with the
arts in which it has become embodied, even the special art of ship-sailing, which
lies nearest to it. Its enlargement in modern times with special practical refer-
ence to steam (6*), and its more general relationship to commerce (6°), has
caused the titles of a few of its books to be duplicated under those heads.

Mechanics, in the order of sciences, should come under mathematics; as 2+,
but owing to the number of books which go into the details of machinery and
describe processes, it has been placed with applied mechanics, under manufac-
tures (6”). When the arrangement was first made out, 2* was called mechanics,
or technology, and 2° physics; but after a multitude of cards had been written
with the latter mark upon them, and still none appeared for pure technology, or
only one or two, while many were observed to require close connexion with
manufactures, the mistake was unfortunately committed of suppressing the
division 2* entirely. No complete arrangement, however, can be made with-
out it.

Civil engineering occupies an anomalous station. Its correlate among the
scientific arts is geodesy (2°); among the mechanic arts, architecture (7°).
Works on civil engineering, as a science, are extremely few, and these few ought
certainly to form a subdivision either with geodesy or with architecture. Yet
after trial in both places they were finally grouped with a variety of other kindred
matter under manufactures (67). For to this apparently alien locality had been
also banished the numerous reports on railroads, canals, and works on steam,
under the pressure of a hardly describable convenience, which only those will
understand who are obliged to handle masses of such literature. The conveni-
ence here obeyed was, however, a true index of the natural relationships which
this whole branch of literature sustains to the class of the social sciences and
arts. But the very epithet of civil, applied to this kind of engineering, places
it in the sixth class, with the same certainty that mining engineering goes into
the third.

Class IIT. Chemistry, as the abstract science of molecular life, must be con-
sidered the mathematics of the inorganic material world; and it is only at first
confusing that the name (which cannot now be changed) means also the practical
applications of this knowledge, and all that flows from it, to the arts of life.
Chemistry may be as necessary to medicine and to manufactures as to metal-
lurgy; yet it will not be doubted by any man of science that in a correct
classification chemistry and metallurgy will go together, and with mineralogy
and geology; and will leave medicine and manufactures to find their own, per-
haps very distant places, for themselves. Medicine will carry pharmaceutics with
it, and under manufactures will go dyeing, salt-making, soap-boiling, and a
hundred other chemical arts of common life; but chemistry will still maintain
its true position as the opening division of the class of the inorganic sciences,
with two chief subdivisions into inorganic and organic chemistry.

Mining engineering might, with some propriety, be grouped with mineralogy
in 3’, as agriculture is with botany in 4°. But this place is preoccupied by
metallurgy, between which and geology the department of mining engineering
practically and naturally interferes. It has therefore been made a division by
itself, 3°.

Paleontology, merely as a transition from the study of the inorganic to the

ON THE CLASSIFICATION OF BOOKS. AMA

study of the organic, might be placed either at the end of the one or at the
beginning of the other class. Its essential spirit allies it with Class LV of the
organic world. Its literature, however, is so entirely geological that no room
is left for questioning, and it cannot even form a separate division, but must
be grouped with geology, in 3%.

Class IV. Natural history (4') should be called biology, or the science of
organic life, as chemistry is the science of inorganic life. Its specifications
follow in botany (4? 4), zoology (4° a), and human physiology (4 a), with
which again are grouped their practices in life, agriculture (4° B), acclimation
(4° B), and surgery, medicine, &e., (4 8.) But there are many books of min-
gled botany and zoology, especially those written in or previous to the revival
of natural sciénce in the eighteenth century, which either discuss the nature
of life, or systematize the phenomena of life in so general a way that it seems
best to retain the old name for thé science of organic life in general for the first
division of the class, and to put all such memoirs and synopses into it.

It would have been easy to have adopted the name of physiology for this
leading division, had it not become engaged to a special branch of biology,
although some have endeavored to distinguish physiology from human physi-
ology. .'The name, zoology, has been still more closely confined to a specialty,
and cannot now be released to assume its natural place at the head of the sciences
of organic life. Natural history, therefore, vague and unsatisfactory as the
name is, seems to be the best within our reach to designate not only purely
biological works, but works of general description and classification. Its sub-
divisions, then, ought to be into three, natural history societies’ publications,
biological treatises, and principles of classification of genera and species.

Acclimation (4° B), with the few books treating of it, was at first considered
only an insignificant or accidental part of agriculture. But having attained the
rank of a self-sustaining science, lackeyed by one of the most powerful societies
in I'vance, la Société Zoologique d’Acclimatation, it must be allowed to assume
its normal place beside zoology, making this fourth class the most symmetrical
one of the eight.

An apparent anomaly, however, will be noticed by naturalists in the order of
subjects under some of the divisions, such as botany and zoology; they de-
scend instead of ascending. But this is an inherent and unconquerable difficulty
in the sciences themselves, forcing itself upon the classification of their books.
In geology, especially, the order of time and of running description is from lower
to higher rocks; but the order of illustration and of minute description is from
above downwards, both in nature, in the field-book, and on the printed page.
Hugh Miller has made it an argument for the orthodoxy of the fall of man and
eternal damnation, that nature involves this very anomaly, and has seen herself
obliged by the creative destiny to usher in her several creations of higher and
higher types per saltum, only to mortify herself with the sight of their relapses
into degradation and decrepitude, followed by extinction.

Class V. With the completion of the physico-organic we enter the organo-
spiritual range of sciences. And here is encountered perhaps the principal
difficulty in developing the whole theme on a consistently advancing and ascend-
ing scale. We have seen it take root in the abstract soil of number, form its
stem and branches of the inorganic world, blossom with forms of organic life,
and bear its fruitin man. There remains the discussion of the varieties, the
uses, and the reproduction of this fruit. A new theme thus arises out of the
body of the old, like a star-fish from a jelly-fish, to repeat, with a distincter and
nobler pronunciation, the fading outlines of the mother theme. ‘The practical
question may be put in several ways.

We have ceased to regard mankind physiologically as animal. How shall we
now consider man as personal? Shall we consider him, first, intellectually as a
mechanic, then esthetically as an artist, then morally as an immortal? Many

492 ON THE CLASSIFICATION OF BOOKS.

would prefer this order; and it has an outward show of regular development.
But, when examined closely, it is seen to confuse the natural system. It is
empirical. It establishes a doubtful precedency for one kind of art before another.
It leaves several chief heads, such as law and philanthropy, to say nothing of
political economy and the whole historical department, unprovided for, and is
therefore incomplete.

To state the question in another way: Having considered mankind in nature,
shall we next consider mankind in society, and afterwards the individual person?
This also, although a reasonable order, is practically too large and crude. Some-
thing more specific and_precise is needful.

Having considered mankind as a physiological idea, correlative with but
generically (or ordinally) distinct from and superior to the rest, and in fact closing
up the statement of the whole organic world, we pass to the consideration of the
realizations of this highest physiological idea in time and in space, which are
its two most abstract and universal formule. In other words, having described
the earth, and its genera and species of inhabitants, and mankind as one of
these, we arrive at the description of the relations which this mankind holds to
the world so inhabited—relations first of time and also of space. Now then
come up in proper series all those questions of the origin and the migrations of
human races, to settle which exist the sciences of chronology, ethnology,
archeology, mythology, and general history. That these questions involve
discussions of intellectual and spiritual phenomena is true, but only by the way,
and incidentally. ‘Their sciences are essentially humano-terrestrial, and only
prepare the way for the nobler social and moral sciences. Chronology (5!) leads
off, because it is the mathematics of the class, and on its deductions ethnology
(5?) relies. Archzeology (5° a) follows, bringing forward with it, and retaining
at its side, its protégé mythology (5° B), in spite of the kindred ties between
the latter and religion (7°). History (5') sums up the whole, and invites atten-
tion to the next great group.

The only serious difficulty met with in reducing these ideas to practice oceurs
in the matter of historical documents (5* B), which form so large a collection in
this and other libraries. Their proper place, in the most perfect system, is not
exactly with general history, for they are chiefly the records of single acts and
individual lives, and illustrate much higher relationships than that of man with
earth. But, on the other hand, the distinction between history and its docu-
ments is obscure. Historical text-books, monographs of particular eras, reigns,
and individual events, graduate insensibly into pamphlet forms; while bound
volumes of historical addresses, rare political squibs and speeches in Congress
or in Parliament, can, after all, stand nowhere in a library so usefully, and
naturally as on the shelves of history.

Class VI. Sociology (61), including, of course, statistics, holds the same relation
to the sciences of affairs in the world of men (on which we now enter) that
mathematies holds to the sciences of measurement in the world of number, that.
chemistry holds as the science of molecular arrangement in the world of matter,
and that biology holds to the sciences of individuality in living beings. Further-
more, its relation to the world of the present is the same as that of chronology
(5') to the world of the past. Its questions which now meet us are those of man
with man. It leaves to the last-named class all those questions of preliminary
fact respecting man and the earth. It takes the past for granted, and proceeds
to determine the values of societies of men, considering their status on the
earth, their accumulations of industry, the wealth of nature at their command,
the energetic forces of invention and association, and the intelligent self-con-
struction and self-preservation of society. Manufactures (67), commerce (6%),
war (6%), and law (6°), are its four groups of phenomena, coming in their natural
order of advancing intelligence. The legal science is the logical consummation
of this class, as religion ecnecludes the next.

ON THE CLASSIFICATION OF BOOKS. 423

Simple as is this arrangement in the whole, there are many obstacles to its
perfect application in detail, but none of them insurmountable.

Financial science, for instance, including pamphlets on free trade and tariff,
stands intermediate between amanda and commerce, dealing with both.
Its treatment is, however, necessarily fundamental, involving the most recondite
principles of sociology. It is sociology in one of its governmental aspects. It
has, in all ages, been considered as the main body of the science of government.
It is in fact political economy. Unfortunately for the world, but fortunately for
the arrangement of libraries, benevolence and religion are not considered sufti-
ciently allied to politics to make any close connexion between the sixth and
seventh classes necessary, except through law and language.

There is still another reason for throwing finance into the first and general
division of political economy (6), as books which cannot go either into ‘botany
or zoology are placed in natural history.

Manufactures and the mechanic arts (6”), as has been already said above, are
grouped together, and involve the building of steam-engines, steamboats, canals,
and railroads, and therefore the discussion of steam as a power.

For a similar reason, under commerce (6°) come the subjects of money, coins,
and medals, although the science of money value belongs with finance in political
economy, and medals ought to go into archeology and history.

Legislation is in like manner ‘grouped with law (6°), although it carries a far
wider range, and is, in fact, the science of applied sociology —the effort to
embody social ideas of every kind in statute form. Its relation to history, also,
is very intimate.

While this sixth class is apparently the simplest of all in its arrangement, it
is in reality the most confused and difficult to adjust, as it is by far the most
important of all in the number of its titles.

Class VII. The elass of sciences of which language forms the first division
(71), places us, on leaving the world of the social sciences, in the world of man’s
highest and larges st relationships—as an individual, with other beings as indi-
viduals, and with ideas as if they were individual beings. Sociology is the
language of societies; language is the sociology of man’s allied intelligences.
The science of language is the mathematics of the soul. Language, as the
analogue of pure oahemates. is the science of man’s power to express his
thoughts and feelings. Its applications, therefore, are to belles-lettres (7°), the
fine arts Cia), ethics, (7*), education (7°), and worship or religion (7°.) These
are all parts of speech. They are the utterances of successively higher and

higher elemental and essential forces of the being. Contracting their areas as
they ascend, they terminate in a highest point, where the one man regards the
one God. This is the end of the sciences. Here is no more language, but
silence. Nothing can follow but retrospection and personal narration, which is
biography, destined to stand by itself, as Class VIII, at the end, as general
science stood by itself, as Class I, at the beginning.

Under ethies (7*) are put books of metaphysics, so called for the convenience
of the consulter. They strictly belong in language, being nothing else than
books of the natural history of the mind; but no one would be likely to look
for them there. Some may object that metaphysics has not been named the first
division of the class of spiritual sciences. If the word had not been perverted
from its best and widest meaning, and reduced to the denomination of a specialty ;
the mere classification of the faculties of the mind, it might have stood in that
position. But even then the symmetry of the arrangement would have been
lost—the opening of language, the advance through | poetry, sculpture, music,
and logic, to ethics and the works of virtue, to me taphy sical understanding, to
Cigictian faith and hope, and to the personal intercourse with God in praise and
prayer.

Under education (7°), the instruction of the deaf and dumb, the blind, and

424 ON THE CLASSIFICATION OF BOOKS.

the idiotic, are placed with that of other kinds; but the treatment of the hope-
lessly insane could not reasonably be placed anywhere but with medicine, in 4*.
This is one of the cases of forcible divorce of classes of books commonly kept
together.

Prison discipline, also, (which some might expect to find in the social class,
VJ,) and, in fact, philanthropy in general, is grouped with education (7°).
Others might insist upon making a distinct division; but any one who handles
the literatures of both classes will find it practically impossible to separate them
more widely.

After this analytical statement of its genesis, it is only necessary to reproduce
the whole scheme before the reader’s eye and leave him to make what use of
ithe can. It is no just objection to any good arrangement of a library that it
requires study to be used. It would be unskilful, indeed, if it did not. Students
of books must learn the contents of each book by studying the author’s arrange-
ment. How much more needful to learn the contents of a library by a careful
analysis of its departments! It is the librarian’s duty to save a large part of this
labor to the consulters of the library, by a more complete and conscientious
analysis than any they can find time to make. ‘The least that they can do is to
become accustomed to this analysis when made. Libraries are commonly.
arranged without, or previous to, any analysis, and in obedience to local accidents
or temporary expediency; and, in the case of those which crowds of readers
throng, it is not to be so much wondered at. But in quiet libraries it is always
possible to collect books of one subject into one place, that the reader may have
the entire treasury of that theme before his eyes.

The eight classes of our books are thus collected into eight suits of bookeases,
as their titles on cards are arranged in eight drawers. 'To facilitate the handling
of the books, they are also spotted on the back with paper patches of eight dit-
ferent colors, corresponding to the eight suits of bookcases; and each different
drawer of the card catalogue is filled with cards of a corresponding color. It is
not easy, therefore, for either a card or a book to get astray. ‘The convenience
might be extended to the printed catalogue by tinting the pages devoted to
cach class division with its appropriate color. In the choice of colors there
was nothing arbitrary. White being, of course, the color for the first class,
general science, the colors of the other seven followed in the order of the solar
spectrum :

For mathematics, &c..--- jot gue ban. oeld tated hendices LE.
Forchemistry: &esh..onsohsmoc aoe orange... .III.
For natural history ee" alc. fais. dhe Ls yellow s:.\: «EM
tor chronolory, Get sects fs Se eI Bad ae preenit ni. 6 Vs
Hor sociology; cei <2 ad Juda. Apse sees St: bliedzi: 22 -Vit:
For language, &c-...:. 2... Sos els rstiaueteen indigo..-. VII.
For biography, &c.--...... Bhis. Ald. Ae eee wioletecnis- VIII.

Under the principal analytical law of arrangement of the library, rule two
others—the one a law of space, the other a law of time.

Wherever a geographical arrangement could be made out, it was adopted.
Such was the case with learned societies and their publications, and the cata-
logues of libraries; with astronomical observatories and their observations;
with books of geography, and voyages and travels; with whole ranges of books
in the various physical sciences; with books on ethnology, local history, local
manufactures, local laws, and legislation; with books on language, belles-lettres,
&e. And the geographical sequence proceeds, like that of history, from the
cast westward,

Tn all other cases, and in all the sub-sections throughout the catalogue, a

ON THE CLASSIFICATION OF BOOKS. 425

chronological arrangement is adopted for rapid reference; and, to take the utmost
advantage of it, the dates of books are arranged in column on the right side of
the page. This column should properly be on the left side of the page, but
some allowance was considered due to tradition and the custom of the reader’s
eye. In consulting a catalogue for a book, perhaps the most natural reference
first made is to the time of its appearance. Every catalogue might properly
make its statements in the following order: “In this year ( ) a work ap-
peared of this size( °),andinthis( ) number of volumes, entitled thus (8);
its author was M. , and he published in such a place; the work is in (vel-
lum, calf, paper, &c.,) and is to be found in the bookease with this number on
its back (. ).” i

This chronological arrangement is practical and handy; and the books of all
the principal divisions of the library are so arranged on the book-shelves—the
oldest at the left-hand end of the uppermost shelf, and the rest in order of their
dates. The reader, who has forgotten both title and author’s name, can find,
with little search, his book, if he only knows the subject of it‘and about the
date of its appearance. Another most important advantage is obtained: there
is no need of renumbering the books of a library when thus arranged. By
writing the dates upon the spots of colored paper on the back, the end of num-
bering the books is gained without the annoyance of posting two sets of numbers,
one of which means nothing. Interpolation of new books is also easy and
natural. The inconvenience of having half a dozen books of the same date is
too sheht to notice.

‘The more serious inconvenience encountered in the case of serials, especially
in the case of interrupted series of proceedings, transactions, acts, memoirs, and
magazines, may be readily overcome by numbering all of a series of one date,
viz: the date of the first volume, or, better yet, by placing all the living serials
of a division at the end of a suit of cases of that division, where they will not
interfere with the chronological arrangement of the books, and where, also, they
can be increased by periodical additions.

Of course, in all this, it is understood that the size of books is disregarded,
except where a lower shelf or shelves are given to quartos and folios. This
may be a fatal objection to the whole plan, in the view of those who are more
disposed to please the eye in regarding than to assist the brain in handling a
library. But working scholars are soon cured of undue zstheticism in externals,
and a little extra height allowed to each shelf space admits even the smaller
folios into their chronological places.

It will be noticed that the column of volumes and pamphlets which stands
next to the titles on each page of the catalogue, omits any statement of a book
or pamphlet, except in that class and division in which the book or pamphlet
is actually to be found in the library; otherwise, in summing up the number
of books in the library, the same book would be counted as many times as its
title happened to need duplication in different parts of the catalogue, and the
search for it among the books of the library would also give that much addi-
tional trouble.

426 ACCOUNT OF HUMAN REMAINS FROM PATAGONIA.

ACCOUNT OF HUMAN REMAINS FROM PATAGONTA

IN THE SMITHSONIAN INSTITUTION.
PRESENTED BY DR. AQ. RIED.*

The accompanying female mummy was found about two months ago on the
west coast of Patagonia, in latitude 44° south, near a point marked on the charts
“Refujio bay.”

A considerable number of human skeletons and detached human bones were
discovered, occupying a species of cavern on the face of the rocks that bind the
coast, at an elevation of about one hundred feet above high-water mark, and at
no great distance from the beach. Some of the skeletons retained part of the
hair, integuments, and soft tissues, in various stages of decomposition; the body.
under consideration was, however, the only one in a state approaching preserva-
tion. Hew similar specimens have hitherto been procured—two are in the
national museum at Santiago; a third was sent about ten years ago to the
museum at Ratisbon, in Bavaria, by the writer of these remarks; and the fourth
is the one herewith presented to the Institution.

That few human bodies should be met with in these regions, even so imper-
fectly preserved as the one in question, is not to be wondered at, if we take into
account the climate, so peculiarly unfavorable to the preservation of animal
fibre, on account of the quantity of moisture with which the atmosphere is
impregnated.

We possess no reliable observations on the temperature of the district, but
navigators and hunters agree in stating that ¢ce is a rare occurrence, and that
snow never remains long on the ground. 'The winter consists of a scarcely
interrupted series of gales, with heavy rains, and lasts for upwards of six months
of the year. Although sheltered from the direct action of the snow and rain,
the bodies lay exposed to the indirect influence of atmospheric changes—the
caverns being of no great depth, and the bodies completely uncovered.

The question naturally presents itself, From what cause have these bodies
resisted the decomposing action of putrefactive fermentation? Are there any
local natural causes to explain a phenomenon which appears in contradiction
with what might be expected under ordinary circumstances, but particularly under
those mentioned? I am not aware that any notice has been taken of this fact
by any writer on natural history; and yet it appears sufficiently interesting to
deserve attention.

From the northern border of Patagonia up to the southein termination of the
great desert of Atacama, the human body, after death, goes through the usual
process of decay. No doubt in Patagonia the same result takes place, but there
are evidently numerous exceptions to the rule, as many skeletons are met with
on which the soft parts are only exsiecated, tendons and muscles adhering to
the bone, in a state of semi-preservation.

To suppose that the bodies had been made to undergo some preparation de-
signed to preserve them, would be to assume the existence of a state of civilization
which no collateral evidence warrants us in doing. Besides, the bodies them-
selves present no traces of the employment of any artificial means for such a
purpose.

* See page 87 of this Report.

ACCOUNT OF HUMAN REMAINS FROM PATAGONIA. 427

The sitting posture in which these bodies are found, and which is peculiar to
the tribes that inhabited the countries comprised in the ancient Inca empire,
indicates that they were not intended to be buried under ground, but to be
deposited in some situation where they might be accessible to their friends.
Some implement of domestic or warlike use is generally found in the immediate
neighborhood of the body, as, in the present case, the rude attempt at a cutting
instrument, fashioned out of stone, and the dish, consisting of the outer shell
of a kind of calabash.

There are not wanting those who, determined on adapting all things to their
favorite theories, choose to discover analogies between the mummies of Egypt
and South America, and to deduce therefrom the direct connexion of these tribes
with, if not their descent from, the inhabitants of the Old World. Nothing
can be more vague or void of foundation. The one is the result of an artificial
refined religious superstition, the other has been forced upon man as a conse-
quence of peculiar local cireumstances. The only analogy between them is
that they are both intended as an homage to the dead. ‘The feeling that led
the Pharaohs to build pyramids, and the Moguls to erect mausoleums, is the
same that induced our rude savage to lay these harmless utensils at the feet
of his departed friend.

In the rainless regions of the west coast, nearly all of which are contained
within the Inca empire, many local circumstances combined to direct our
attention to this otherwise anomalous method of treating the dead. The atmos-
phere is excessively dry, the soil impregnated with alkaline matter, nitre, and
soda, in varied combinations, almost everywhere in abundance, thus modifying
the process of putrid fermentation, so as to render it exceedingly slow, or to
suspendit entirely. Animals may be seen lying unchanged in many parts of the
country for years after their death, and what more natural than a desire to
preserve the dead when it could be done so easily? In Chili proper, on the
other hand, and in Araucania, which intervene between Peru and Patagonia,
tradition and actual observation proves that the custom of thus preserving the
dead has never prevailed. Indeed, without the employment of artificial means
it would be impracticable, and the aborigines of these districts buried their dead
in the manner as practiced by the majority of nations.

On these premises how is it to be explained that the mummies recur in the
isolated locality where the one before us, and several others, have been found,
separated as they are from the mummy races by a large intervening space and
a people that differ entirely from them in this important social feature? And
how can we account for the connexion which this peculiar custom would lead
us to suspect between the Inca Indian and the remote Patagonian ?

The dimensions of the bones of our mummy are considerably above the
average of those of the surrounding tribes, and even of the majority of the
present inhabitants of Patagonia. ‘The skeleton measures, even in its present
shrivelled condition, fully five feet five and a half inches English, which, allow-
ing for the disappearance of the vertebral cartilages, would give, during life, a
height of something like five feet eight inches, thus almost justifying the some-
what poetical epithet of “gigantic,” as applied to the Patagonians in general.
The fair proportions of the lower extremities are particularly striking, as con-
trasted with the generally abnormal shortness of these members amongst the
Araucanian Indians. The entire individual gives the impression of having
belonged to a race superior, in bone and muscle, to its neighbors as well as
descendants.

The existence of such a race, distinguished by’so striking a physical organ-
ization, in an isolated corner of the continent, under circumstances certainly
not favorable to growth, having to struggle with every kind of privation and
to subsist on the poorest of aliments, is a phenomenon which has not attracted
the attention of scientific men in the degree it merits. ‘The Inca Indians, (or

A28 ACCOUNT OF HUMAN REMAINS FROM PATAGONIA.

the mummy races,) to a connexion with whom the Patagonian mummies would
point, were rather under middle size, and weakly, in comparison to the latter,
although inhabiting a fertile country, with a favorable climate. At the same
time, the inhabitants of Tierra del Fuego, separated from Patagonia only by the
narrow straits of Magellan, present an appearance of almost decrepitude. The
reconcilement of these apparent contradictions would be well worth the study
of ethnologists.

The contact of these races with what is called civilization has not tended as
yet to exalt their sense of morality. Some years ago the attention of the
Chilian government was directed towards these territories. A German officer
of engineers, Bernhard Philippi, explored the region, and having, amongst
other things of commercial importance, discovered coal, the government deter-
mined on establishing there a penal colony. In 1851 the military commander,
Cambiazo, taking advantage of a revolution then raging in the country, amongst
other brutalities, committed the one of hanging some six or eight unfortunate
Indians, who had been guilty of no other crime than that of being in the colony
at the moment. Having quelled the revolution, the government sent Mr.
Philippi to organize the colony. He found the bodies of the murdered men
still hanging, and at once having buried them, commenced a series of negotia-
tions with the Patagonians tending to appease their fears and their anger. His
apparent success was such that trading was resumed, and he was invited by the
chiefs to visit the interior. ‘Two years after he had started, it was ascertained
that both he and his secretary had been murdered a few days after their departure
from the colony, in retribution for the lives sacrificed by Cambiazo.

Although unable to distinguish between the guilty and the innocent, in the first
instance, they must have still possessed the sense of right and wrong to a
certain extent, and their conscience made such cowards of them that for several
years none approached the settlement, and for a long time they could not be-
lieve that retaliation would not be practiced on them.

Althongh furnished with great physical powers, the Patagonians have never
heen a warlike race; their collisions with the neighboring Indians, and their
intestine broils, never assuming anything of a general character. Of their me-
chanical skill the accompanying adze-shaped stone may convey an idea; their
weapons of offence are the rudest imaginable, the principal one being the
“bolas,” of the Spaniards, or the “lakhi,”’ of the Araucanians.

Of the four skulls which I have the honor to present to the Institution, the
one marked No. 3 belonged to an Indian of the “ Pampa,” the northeastern
frontier of Patagonia, who has been killed by the above-mentioned weapon.
The “lakhi’’ consists of two, or sometimes three round stones of the.size of
a small orange, covered with raw hide, and connected by pieces of thong of
the same material. In war they are used of dead, and it is evident that the
Llow, in the present case, has been given by a weapon of the latter description,
as the force necessary to fracture the skull by a stone would have caused a
much more extensive gap in the bone; whereas the blow of the lead, being
conveyed with greater energy, would produce a more circumscribed wound.
The individual had been killed in an incursion of the Pampa Indians towards
the south, and the skull was procured by the surgeon of the colony. It is
dificult and dangerous to collect such remains, as the Indian will sooner forgive
you for killing his companion than for abstracting any part of a dead body. 1
plead this in excuse of the defective state in which the specimens are presented.
‘Phe skull, marked No, LY, was found about eighteen leagues (fifty-four miles)
from the Chilian settlement towards the northeast, and presents a striking differ-
ence from the former one, Neither does it resemble many others found in the
same region; and the excessive flatness of the superior anterior portion, the great
breadth of the posterior inferior region, and the position of the foramen magnum,
would lead to the supposition that it belonged to an inhabitant of «Tierra del

ACCOUNT OF HUMAN REMAINS FROM PATAGONIA. 429

Kuego,” one of the lowest branches yet discovered of the human family.
This is neither impossible nor improbable, as feuds between the tribes are con-
stantly occurring, and the individual may have been dragged into the interior
as a prisoner of war. ‘The large size of the temporal muscles points to carnivo-
rous habits.

The skulls, Nos. I and II, are those of two Araucanian Indians, who were
killed in the late collision of these tribes with the Chili troops. ‘The number
and nature of the sabre cuts and fractures testify to the barbarism Of the
contest, as well as to the clumsiness of the combatants. An anecdote is con-
nected with them which is rather characteristic. On being exhibited in the
custom-house in Valparaiso, the authorities, who had no idea of any scientific
object being attachable to the skull, inquired of me what “martyrs” they had
belonged to. Although both skulls in question belonged to pure Araucanians,
still, I do not consider them as specimens of an wamexed race. ‘Whe upper
and anterior portion of the brain is but poorly developed, the parictal diameter
execedingly small, and the cerebellar portion preponderating. Yet, the difter-
ence between them and the mummy—the one marked No. 11—and even the
Pampa Indian, is such as to warrant the presumption that the race had been
crossed with a superior one, although in a slight degree. The supraorbital
processes are, as found in men of violent passions, endowed with a large
amount of animal life, and the position of the foramen magnum approaches
more to that of the European skull than the purer Indian. The centuries of
intercourse with the Spaniards and their descendants, and the consequent
introduction of squatters, deserters, and prisoners, besides the not unfrequent
abduction of white women, sufliciently explains this intermingling of race.

Sut it will not suffice to explain all that is told to us about these wandering
tribes by the Spanish historians and poets, who attribute to them elevated ideas
about the immortality of the soul, systems of religion and politics, and noble
qualities such as distinguish the most elevated representatives of the human
race. On view of these stubborn skulls, however, and even admitting that the
crossing with the superior race has not improved them, we must take these
assertions ‘‘cum grano salis,”’ and that a very considerable one. ‘The two
writers on whom the sins of the subsequent compilers may be charged are the
poet Ercilla and the Jesuit Molina. The one, a maker of iong. verses, in
which he describes his own deeds somewhat in the vein of “Ancient Pistol,’’
endeavors to exalt his own prowess by praising his enemy; the other, a simple-
minded priest, narrates, with an enviable credulity, historical facts in a poetical
manner, and without the critical acumen which ought to distinguish the histo-
rian. ‘Che fables which the credulity of the one and the exaggeration of the
other of these two celebrities, let loose upon the world, have been repeated by
their compiling successors down even to “ Monsieur Gay,’’ who, although paid
by the Chili government for writing, amongst other things, a critical history
of the country and its inhabitants, repeats the received traditions without
much inquiry into their soundness. As the history’ of these races has been
thus rendered obscure by the barbarism, ignorance, and superstition of the
first invaders, and as their architectural and industrial relics are too few to
vuide us securely in our investigations, the mummies and osseous remains
which are found in great abundance and in varied situations, form a valuable
cue to the observer, and may enable him to solve much of what without them
would remain unexplained. Hence, I venture te submit the subject to the
attention of the lovers of ethnological inquiry.

VALPARAISO, June 4, 1862.

43 PRIZE QUESTIONS OF SCIENTIFIC SOCIETIES.

PRIZE QUESTIONS OF SCIENTIFIC SOCIETIES.

INSTITUTION OF CIVIL ENGINEERS, LONDON.
SUBJECTS FOR PREMIUMS, SESSION, 1863-64.

The Council of the Institution of Civil Engineers invite communications on
the subjects comprised in the following list, as well as upon others; such as,
Ist. Authentic details of the progress of any work in civil engineering, as far
as absolutely executed (Smeaton’s account of the Edystone light-house may be
taken as an example;) 2d. Descriptions of engines and machines of various
kinds; or 3d. Practical essays on subjects connected with engineering, as, for
instance, metallurgy. For approved original communications on these, or other
subjects, the council will be prepared to award the premiums arising out of
special funds devoted for the purpose.

1. On the decay of materials in tropical climates, and the methods employed
for arresting and preventing it.

2. On the theory of metal and timber arches.

3. On the theory and details of construction of wrought-iron girder bridges.

4. On land-slips, with the best means of preventing, or arresting them, with
examples.

5. On the pressure of earth on tunnels, and the conditions which limit its
amount.

6. On the theory and practice of artesian well-boring, and of sinking large
shafts, as now practiced on the continent.

7. On the results of contrivances for facilitating the driving of tunnels, or
drifts in rocks.

8. On the principles to be observed in laying out lines of railway through
mountainous countries, with examples of their application in the Alps, the
Pyrenees, the Indian ghauts, the Rocky mountains of America, and similar
cases.

9. On the best means of preserving railways in Alpine countries from intey-
ruptions from snow.

10. On the results of recent experience in iron permanent way.

11. On the principles to be observed in the designing and arrangement of
terminal and other railway stations, repairing shops, engine-sheds, &c., with
reference to the traffic and the rolling stock.

12. On railway ferries, or the transmission of » ilway trains entire across
rivers, estuaries, &e. 3

13. On locomotive engines for ascending steep inclines, especially when in
combination with sharp curves, on railways.

14. On the working of locomotive engines in long tunnels, with frequent
stations.

15. On the results of the application of Giffard’s injector to the boilers of
locomotive and other engines.

16. On the working expenses of railways, and the influence on these of the
original design and construction.

17. On the results of a series of observations on the flow of water from the
ground, in any large district, with accurately-recorded rain-gauge registries, in
the same locality, for a period of not less than twelve months.

PRIZE QUESTIONS OF SCIENTIFIC SOCIETIES. 431

18. On the construction of catch-water reservoirs in mountain districts, for
the supply of towns, or for manufacturing purposes.

19. Accounts of existing water-works, including the source of supply, a
description of the different modes of collecting and filtering, the distribution
throughout the streets of towns, and the general practical results.

20. On the best means of improving the water supply of the metropolis.

21. On the structural details, and the results in use, of apparatus for the fil-
tration of large volumes of water. f

22. On the drainage and sewerage of large towns, exemplified by accounts
of the systems at present pursued with regard to the level and position of the
outfall, the form, dimensions, and material of the sewers, the prevention of
emanations from them, the arrangements for connecting the house drains with
the public sewers, the best means of limiting the contamination of rivers from
the sewage discharged into them, and the disposal of the sewage whether in a
liquid form, as irrigation, or in a solid form, after deodorization.

23. On the results of the employment of steam-power on canals, and of
other measures for the improvement of canals as a means of conveyance for
heavy traflic.

24. On iron paving, and a comparison of the results attained by it, and by
stone block paving, &c.

25. A history of any fresh water channel, tidal river, or estuary, accompanied
by plans and longitudinal and cross sections, including notices of any works
which may have been executed upon it, and of the effects of the works, par-
ticularly of the relative value of tidal and fresh water, and of the effect of en-
closures from the tidal area upon the general regime of sluicing where applied
to the improvement of the entrance or the removal of a bar, and of groynes,
or parallel training walls ; also of dredging, with a description of the machinery
employed, and the cost of raising and depositing the material.

26. On the results of a series of observations, illustrative of the modifica-
tions which the tidal wave undergoes in its passage up and down a river, or
estuary.

27. On the construction of tidal, or other dams, in a constant, or variable
depth of water, and on the use of wrought iron in their construction.

28. A history of any harbor, or dock, including the reasons for selecting the
site, the mode of construction adopted, and the subsidiary works for the con-
venience of shipping, and for commercial purposes, with the cost, &c.

29. On graving docks and mechanical arrangements having a similar object,
with the conditions determining their relative applicability in particular cases,
as dependent on the rise of tide, the depth of water, and other circumstances.

30. On the arrangement and construction of floating landing-stages, for pas-
senger and other traffic, with existing examples.

31. On the different systems of swing, lifting, and other opening bridges,
with existing examples.

32. On the construction of light-houses, their machinery and lighting appa-
ratus, with notices of the methods in use for distinguishing the different lights.

33. On the measure of resistance to steam vessels at high velocities.

34. On the results of the use of tubular boilers, and of steam at an increased
pressure, with or without superheating, for marine engines, noticing particularly
the difference in weight and in speed, in proportion to the horse-power and the
tonnage.

35. On the relative advantages of the principle of expansion, as applied in
the single long-stroke cylinder engine, in the double cylinder engine, and in the
three-cylinder engine, and on the adaptation of the two latter to marine pur-
poses.

36. On the principles and varieties of construction of blast engines, with
British and foreign examples.

432 PRIZE QUESTIONS OF SCIENTIFIC SOCIETIES.

37. On the best description of steam fire-engines, and their power and
efficiency, as compared with ordinary hand fire-engines.

38. On the construction of, and the comparative duty performed by modern
pumping engines for raising water for the supply of towns, or for the drainage
of mines, noticing in the latter case the depth and length of the underground
workings, the height ot the surface above the sea, the geological formation, the
contiguity of streams, &e.

39. On turbines and other water motors of a similar character, and their con-
struction and performance, in comparison with water-wheels.

40. On the present systems of smelting iron ores, and on the conversion of

cast iron into the malleable state, and of the manufacture of iron generally,
comprising the distribution and management of iron works.

41. On the manufacture of iron ee rails and wheel tyres, having special
reference to the increased capability of resisting lamination and abrasion, and
accounts of the machinery required for rolling heavy rails, shafts, and bars of
iron of large sectional area.

42. Ou the manufacture of large masses of iron for the purposes of warfare,
as armor plates, &c.

43. On the construction of rifled and breech-loading artillery, and on the
initial velocity, range and penetration of rifled projectiles, and the influence of
atmospheric resistance.

44. On the use of steel bars and plates in engine work and machinery, for
boilers and for ship-building as well as for bridges.

45. On the use of steel in the construction of locomotive engines, especially
with reference to durability and the cost of repairs, in tyres and cranked axles,
as compared with iron of acknowledged good quality.

46. On the Bessemer and other processes of steel-making, on the present
state of the steel manufacture on the continent of Europe, and on the employ-
ment of castings in steel for railway wheels and other objects.

47. On the safe working strength of iron and steel, including the results of
experiments on the elastic limit of long bars of iron, and on the rate of decay
by rusting, &c., and under prolonged strains.

48. On the transmission of electrical signals through submarine cables.

49. On the present relative position of English and continental engineering
manufactories, especially with reference to their comparative positions in respect
of the cost and the character of the work produced.

50. Memoirs and accounts of the works and inventions of any of the follow-
ing engineers: Sir Hugh Middleton, Arthur Woolf, Jonathan Hornblower,
Richard 'Trevithick, William Murdoch (of Soho,) Alexander Nimmo, and John
Rennie.

Original papers, reports, or designs of these or other eminent individuals
are particularly valuable for the library of the institution.

The competition for premiums is not confined to members or associates of
the institution, but is equally open to all persons, w hether natives or for-
eigners.

“The council will not consider themselves bound to award any premium
should the communication not be of adequate merit, but they will award more
than one premium should there be several communications on the same subject
deserving this mark of distinction.

The communications must be forwarded, on or before the 1st of January,
1864, to the house of the Institution, No. 25 Great George street, Westminster,
5. W., where copies of this paper, and any further information, may be ob-
tained.

CHARLES MANBY, Honorary Secretary.
JAMES FORREST, Secretary.
25 GREAT GEORGE STREET,
Westminster, S. W., August, 1863.

PRIZE QUESTIONS OF SCIENTIFIC SOCIETIES. 433

Extracts from the minutes of council, February 23, 1835.

The principal subjects for which premiums will be given are :

L. Descriptions, accompanied by plans and explanatory drawings, of any
work in civil engineering, as far as absolutely executed ; and which shall con-
tain authentic details of the progress of the work. (Smeaton’s account of the
Kdystone light-house may be taken as an example.)

2. Models or drawings, with descriptions of useful engines and machines ;
plans of harbors, bridges, roads, rivers, canals, mines, etc.; surveys and sec-
tions of districts of country.

3. Practical essays on subjects connected with civil engineering, such as
geology, mineralogy, chemistry, physics, mechanic arts, statistics, agriculture,
ete., together with models, drawings, or descriptions of any new and useful ap-
paratus, or instruments applicable to the purposes of engineering or surveying,

Excerpt by-laws, section XIV, clause 3.

Every paper, map, plan, drawing, or model presented to the institution shall
be considered the property thereof, unless there shall have been some previous
arrangement to the contrary, and the council may publish the same in any way
and at any time they may think proper. But should the council refuse or delay
the publication of such paper beyond a reasonable time, the author thereof
shall have a right to copy the same, and to publish it as he may think fit,
having previously given notice, in writing, to the secretary, of his intention.
No person shall publish, or give his consent for the publication of any com-
munication presented and belonging to the institution, without the previous
consent of the council.

Instructions for preparing communications.

The communications should be written in the impersonal pronoun, and be
legibly transcribed on foolseap paper, about thirteen inches by eight inches, the
lines being three-quarters of an inch apart, on the one side only, leaving a
margin of one inch and a half in width on the left side, in order that the sheets
may be bound. é

The drawings should be on mounted paper, and with as many details as may
be necessary to illustrate the subject. Hnlarged diagrams, to such a scale that
they may be clearly visible, when suspended on the walls of the theatre of the
institution, at the time of reading the communication, should be sent for the
illustration of any particular portions.

Papers which have been read at the meetings of other scientific societies, or
have been published in any form, cannot be read at a meeting of the institution.
nor be admitted to competition for the premiums.

28 s

434 PROVINCIAL SOCIETY OF ARTS AND SCIENCES, UTRECHT.

PROGRAMME

OF THE

PROVINCIAL SOCIETY OF ARTS AND SCIENCES OF UTRECHT.
1862-65,

The society has awarded no medal for the memoirs which have been offered
since its general session in 1661. The decisions which have been pronounced
on the four memoirs presented during that period by learned strangers are here
summarily given:

1. A memoir in the German language on the heat of plants.
Device: Etenim experimentorum, etc.

The author of this memoir has not placed himself at the point to which the
question had been carried by researches previous to his own. He has, more-
over, employed for his experiments a method which, in the present state of sci-
ence, seems insufficient for the profound study of the question.

2. A memoir in Latin on the veracity of Caesar.
Device: Quanta majora erant, etc.

This memoir has furnished but a slight sketch of the subject—a sketch which
is neither recommended by the order nor logie of its discussions. The results
of researches respecting the opinion of Pollio are not subjected to a judicious
and scientific appreciation. ‘here is even no mention made of the recent at-
tempts which have contributed to elucidate this difficult question. Besides, the
Latin style of the author has given occasion to no slight animadversion.

3. A memoir in German on ventilation.
Device: Luft mehr luft.

It was acknowledged that this memoir is not without merit. Yet it is defi-
cient in a critical discussion of the most important elements of the question :
the manner in which the enclosed air is altered, and the influence which the ma-
terials of constructions exert upon the working of the ventilating apparatus.

4. A memoir in French on the same subject with No. 3.
Device: Jl faut savoir une fois pourtontes, etc.

This memoir treats only of the means of preserving the air in its state of
purity, while the question propounded on the nature of the alteration which
the air undergoes in dwellings is passed by without discussion.

The new questions proposed for competition, the subject of which may be of
interest to learned foreigners, are the following :

1. An exposition of the principles of sound policy which, dating from the
nineteenth century, have prevailed in the relations of Holland with its East
Indian possessions, especially the effect of securing an efficacious protection
against every sort of oppression, as well to the colonists as to the native popu-
lation. A comparison in this respect of English and French laws and ordi-
nances with those of the colonial system of Holland.

PROVINCIAL SOCIETY OF ARTS AND SCIENCES, UTRECHT. 435

2. History of the coinage of money among the Greeks.

3. A memoir on the cnhibitory nerves, (nerfs inhibitoires.) It is requisite
that the author should not limit himself to a critical review of the opinion
already delivered on this subject, but that he should illustrate it by new experi-
ments.

4. A critical exposition of the principles and results of the method of which
Niesuur has availed himself in explaining the Roman history, and of the in-
fluence which the example of this illustrious savant has exercised on historical
studies generally.

5. A series of researches on the heat of plants.

6. Researches on the development of one or more species of animals pertain-
ing to the class of Mollusks, to that of. Annelidex, or to that of the Crustacex,
whose development has not yet been described, accompanied by explanatory
figures.

The prize which will be awarded to each satisfactory response will consist of
a gold medal of the value of three hundred florins of Holland, (about 600
franes,) or of the same amount in money. This prize will be doubled for ques-
tion No. 2. The replies must be written in French, Dutch, German, (Roman
characters,) English, or Latin, and be addressed, post-paid, before November
30, 1863, to the secretary of the society, M. Gunning, at Utrecht. For ques-
tion No. 2, competition will remain open till the 30th of November, 18665.
The memoirs must be accompanied by a sealed note enclosing the name and
address of the author. Accepted replies will be published in the memoirs of
the society. Refer for fuller information to the secretary, M. Gunning.

436 PRIZE QUESTIONS. \

PRIZE QUESTIONS
PROPOSED IN 1862 BY THE ROYAL DANISH SOCIETY OF SCIENCES.

MATHEMATICAL CLASS.

The meridian observations of small stars from the seventh to the tenth mag-
nitude, made by the royal astronomer, Nevel Maskelyne, during a succession
of years, but chiefly in 1767-68, would seem not a little calculated, if vigor-
ously reduced, to extend the catalogues of stars; and as it cannot be doubted
that, from their antiquity and the scrupulous care in making them, these obser-
vations might be of no small utility to a knowledge of the fixed stars, the so-
ciety offers its gold medal to any one who shall accurately reduce them, so that
the mean places thence resulting, for any particular period, may be catalogued
and compared with the positions since assigned by Lalande, Bessel, and Arge-
lander, or with those derived from any other accessible source.

PHYSICAL CLASS.

With the re-agents which we now habitually employ, it is often not practica-
ble to detect with sufficient accuracy and certainty sugar, dextrine, gum, and
starch, especially when a small portion of one or more of these bodies is mixed
with other organic substances. But as it is in many cases of no little conse-
quence to have subtle and suitable re-agents for distinguishing the bodies above
named, the society propounds the question: By what method can it be certainly
decided whether or not sugar, dextrine and starch exist in the fluids and tissues
of animals ?

HISTORICAL CLASS.

Although the ten books on architecture, usually ascribed to Marcus Vitruvi-
ous Pollio, are commonly referred, upon external testimony, to the age of the
Emperor Augustus, yet, whether we regard delicacy of art and dexterity of
construction, or knowledge of letters and style of composition, they seem not to
belong to that golden era. Since the objections advanced on this subject have
never been satisfactorily examined, nor is the authority which should be con-
ceded to the laws and rules of building prescribed in these books altogether ex-
empt from doubt, the society desires that accurate inquiry should be made, re-
specting the age of this writer and his sources of information.

In the discussion of the above questions the Latin, French, English, German,
Swedish, or Danish language may be used at pleasure. Communications must
not be signed with the name of the author, but denoted by some token, and
accompanied by a sealed note containing the same token, and indicating the
writer’s name, style, and place of residence. Competition is not open to the
associates of the society inhabiting the Danish dominions. As a prize, the
gold medal of the society, equal in value to fifty Danish dueats, will be
awarded to the candidate who shall satisfactorily answer any of the questions,
except in cases where some other premium is designated.

Answers must be consigned, before the end of October, 1863, to George
Forchhammer, corresponding secretary of the society.

ACADEMY OF SCIENCES OF THE INSTITUTE OF BOLOGNA. 437

PROGRAMME

OF THE

ACADEMY OF SCIENCES OF THE INSTITUTE OF BOLOGNA

IN REFERENCE TO THE
ALDINI PRIZE FOR RESEARCHES IN GALVANISM, FOR THE YEAR 1865.

No memoir having been presented for competition in 1862, the same subject
is again proposed; and in view of its great importance, and the no slight diffi-
culties attending it, the prize is increased and its conditions modified as follows:

The muscles and nerves of the frog are seats of electrical currents, which
have given occasion to two dissertations crowned by this academy, and elabo-
rated by the chemical professors, Grimelli and Cima, to answer two inquiries
proposed for competition for the Aldini prize. On the authority, chiefly, of a
very recent publication by M. Budge, professor in the University of Grietswald,
the skin is also asserted to be the seat of an electrical current in the frog. The
academy, which has always sought to know clearly and accurately how much
has been ascertained in point of electricity with regard to that animal from
which galvanism had its origin, cannot but desire also to know how much has
been since discovered respecting the same, and of course how much should be
referred to the last-mentioned current. It proposes therefore the following

INQUIRY.

1st. To examine and explain whatever of consequence has been ascertained
by physicists and physiologists, since the above-mentioned dissertations of Pro-
fessors Grimelli and Cima, respecting the muscular and nervous currents, as
well as those of contraction in the frog; and above all, the real importance of
the electro-tonic state of the nerves, by no means inconsiderable according to
the careful researches of M. Pfluger, but almost nothing in the opinion of the
above-named M. Budge. And

2d. To investigate by precise and conclusive experiments whether an elec-
tric current really manifests itself in the skin of the frog, and, if the result be
afirmative, what are the laws of this current; should it be regarded or not as a
physiological phenomena; and has it any dependence on the other currents?

‘he academy wishes that the analogous facts observed in other animals
should not be dissociated from those relative to the frog, but that the former
should be referred to and discussed, thus reuniting in one whatever is well-
known about the animal economy in relation to the object of this discussion,
and within the limit assigned to this competition.

A prize of two thousand Italian lires (nearly $300) will be paid to the author of
the paper which, under the above-mentioned terms and conditions, shall present,
in the judgment of this academy, the best solution of the proposed inquiry.

Memoirs intended for competition must reach Bologna, postage paid, within
the month of December, 1865, plainly addressed to the secretary of the
Academy of Sciences of the Institute of Bologna. ‘This limit is imperative,
and therefore memoirs will not be received for competition which arrive after
the last day of the month mentioned. The memoirs must be written in Italian,
Latin or French, in characters easily legible. The academy requests the
greatest exactness in quotations from printed works, and the highest authen-
ticity in the written documents, to which the authors may have recourse for the

438 ACADEMY OF SCIENCES OF THE INSTITUTE OF BOLOGNA.

proof of corroboration of their assertions. Each competitor must countersign
his memoir with some epigraph, and accompany it with a sealed note enclosing
his name, style and address, the aforesaid epigraph being repeated on the out-
side. Competitors must use every precaution not to make themselves known,
since those who, by some expression of the memoir, or in any other manner,
shall divulge their identity, will be excluded from the competition. At the ex-
piration of the above-mentioned term, and judgment having been pronounced
according to the regulations of the academy, only that note will be opened
which accompanies the accepted memoir, and thereupon the name of the eue-
cessful candidate will be published.

Prof. GUISEPPE BERTOLINI,

President.
Dr. DOMENICO PIANI,
Secretary.

BoLoGcna, RESIwWENZA DEL L’INSTITUTO, 26 Feb., 1863.

e
CONTENTS.
REPORT OF THE SECRETARY.
Page.
Resolution of Congress to print the Report... . oJ). 2202. cee e ee cee cece ee ee ee eee 2
Letter frovmthaiSeetetary to Congress... 022.2 .22.6 see ates eee So. ceic eel e lee 3
iketter from the’ Chancellorand: Secretarys oo ct. 19s. Sos Beek linc cece 4
Officers and Regents of. theplhistituiiones: .caxsesyu. 55 5- eeegceeenaseaeSl oe see 5
Members ex officio and honorary members of the Institution........-.....-..------ 6
Bae anime Ol OLeaniZatlOn ct =ac\nna ete cel weil sens scion ae teeeee See aes 7
Report-of the Secretary, Professor Henry. (For 1862.).-.....2--.- 0.222. 0.22200 13
ineport of ihe Assistant: Secretary, (Cor l862.). «sees ceva ss cee sal sos se lees Joke 46
ieint Ge Donations to the Museu. '255<1.25.05 sstts SU. 5 oboe sole Soe Sesouc eeu 57
List of Smithsonian Publications Gunn SS S62 Jara sqarastst telco ctolattalariaoe eereereror sate eye 60
Wistof, Meteorological Stations:and Observers...==- 20-22 20.62 cocscs'cecces owcose 62
List of Meteorological Material received during 1862..........-.-----.------------ 70
teport of the Executive Committee... .-- SB aaa ay a re ae aces a eas ee area 75
Journal of the Board of Regents, from January 2J, 1863, to February 3, 1868-.-...-- 78
Kulogy on Hen, James A. Pearce, by Professor Bache....-. ...--. 2-250 sce eseeee 100
GENERAL APPENDIX.

LECTURES. ON THE UNDULATORY THEORY OF LIGHT, by Dr. F. A. P. Bar-

SINT RTE te eae oe eee alae) eee ole aoe eee 107
Part I. Introductory—
Outline of) Optical Discovery 2550222 Ysa -t eee eae 107
ibheoriesvolmiioNbseeeececre sin aticiec me =a eeeeme sree 143
Part II. Undulatory Theory—

PS Valb raion. tes om esterase cece eae scene nets 147
O-Undulation = 222 scene eee oat os ae 151
o-), Reteetion and Weftaction..2. (5. 0-2-.6=. sces ses 157
Av Interference: ... occ sc < om Se ee ee ee 162
em TO TEICUIOYE tte a= Sates ets eee pera at epee ee 172
Gj Colors ofethin plates ssssc tee ee eee cn eee ee 183
7. Polarization by Reflection and by Refraction....-.-. 188
8. Circular and Elliptical Polarization by Refleection.... 196
OoPouahye Olan Zationye eee eee eee 200
10; Chromatics! of Polarized Light :2.. 2. s2<2- 22. <5 - 204
tH DoublewRetractionies cesses cee ese eee ties cere 215
Dae VV IGLOS ULE CO pe ore are ere ae ete eee rere laia sa 224
Indexjtoweciuresion: Mehti- sere ss. < cosces -5--- 232
LECTURES. On PuysicaL ETunovoey, by Dr. DANIEL WILSON ..----------- 240
Partueibe American Cranial Mype.-25.6-5-22-.2 2266 os 55 240
Parti Changes in‘Cranial Forms 2-22. -- = jac caes 222 se as 265
Bart si se mimitivesArtetTaCeS = a.c(- acts. slew aie sein bo scene sel 291

LECTURES. Introductory to the Srupy or Higu ANTIQUITY, by A. MORLOT... 303

440 CONTENTS. 7

NORTH AMERICAN ARCHZOLOGY. By JOHN LUBBOCK. «css cces omnis
HISTORICAL SKETCH OF THE ACADEMY OF SCIENCES OF PARIS. By
ME SOUR NS 26 p05 ede Se een ee tara eee Appa
MEMOIR OF LEOPOLD VON BUCH .Byp Mi HWOURENS.<- 225 saee saree sae
MEMOIR OF LOUIS JACQUES THENARD. By M. FLOURENS..-.-.-...---..
MEMOIR OF M. ISIDORE GEOFFROY ST. HILAIRE. By M. DE QUATREFAGES
THE CATALYTIC FORCE, or STUDIES ON THE PHENOMENA OF CON-
TACT, @ prize memoir, by <i. 1. (PHEPSON sso se oe ans seen see
ON ATOMS: By Sit OHNGLIERSCHEL:=- so A--.y- c= -feeet- co emis se sees sees
ON THE CEASSIBICATION- OF- BOOKS.-~ By ie WunSEEY seo 2 ote oases
ACCOUNT OF HUMAN REMAINS FROM PATAGONIA. By Dra Riep. ms ge
PRIZE QUESTIONS OF SCIENTIFIC SOCIETIES—
LONDON INSTITUTION OF CIVIL ENGINEERS, “1863 22-222 22.22... -
PROVINCIAL SOCIETY OF ARTS AND SCIENCES OF UTRECHT. 1862-’63.
ROYAL DANISH SOCIETY OF SCIENCES. 1862.22..22 .222.2222224..2.

395
413
416
426
430
430
454
456

INDEX.

Page.
Academy of Sciences of Institute of Bologna. Programme and Questions...-..-.--- 37
Academy of Sciences of Paris. History of, by Flourens......-.-.--...---------- oor
Beassiz, Prof. Account of.musenm of-2-.<¢ - soe sk\se 55 945 2 S- Stp 4-7 38
Determinationyof Eebini;: by 53 - 3203 a so eqs <s 2 2 4s see see- ser 56
Naming of shells, by -.sgs¢as22GResr a2 ses sleess- 3 & ste t Ee: 35
Agents. Foreign and domestic of the Smithsonian. ..........--.------2-2-2------ 47
Alcock sir ae Naminowotgshells, byjsnqseh-ersmie ssarg- meee eucpeee spr ivcer n-ne -° = 36
ivien, Dr. Hi. . Report on Americam bats; byjos- -4-)-<--erre5- massets--e-risce- ---- 55
Adexander, Cocks ‘Translations; byjamsccwe a3 + qacti- asc see igae nels seq aes 27, 337, 358, 373, 395
AD Etats mPATTrAn MeMent) Ole <artoc seis coe's one ctinnicsieieinisietesit soe cise ene eas ases aes 33
Bachwolony. « Wectures'on, by As Mott (252. cc sco. co cc ee gor eneceeeneetet sees 303
Metter relative to.tromelaeDiles seas cok Nac oo eawerete oem aes tere 8b
North American, a review, by John Lubbock.....-...-...---....---- 318
Atoms: = by: sir dobn Herschel] 3.2 soreness oses 2 ene essa e sae ease eowenae sicaces = 413
Audubon Club of Chieago. Kennicott’s exploration ...--.0..2- 02-065 2255 coon ese 40)
Bache, A.D. Eulogy on Senator J. A. Pearce.-.... Se oe e eee ee ale ert eee 100)
Magnetic observations made at Girard College ...-....-..-.---------. Ez
Magnetic survey of Pennsylvania, New York, Ohio, and Maryland- --.. 2X)
Badger, George fi. Resolution! respecting? <5. .em-- cno< se scms sens sce ws ssasien ee 79
ES BUUNCE aS ee EL peeve |) Olus Oki eee lorries ia ics jninie te miele te see isie jain aie ienia ei araier err 46
awe eh eae dey Moet UreS OM) UM ae eens anne ae jon mone ns sees oa sea =a 107
aromehyciopservations | OM+MOUNtAIMNS << <n.- (co ajsiesiceysieicieyejawieyaiewee so escee + Sas ee 81, 82
Barometers. Comparison of Standards, by Guyot .............----.--------+--0 3]
Bibliooraphy of Concholocy., (By Binney, joc ss io cmijecee catia aan cece Se nee 24
ane: TOMS CAIIGS., DNV ORC OT SHOU Sep anil cg clmn ceinsyerereineiajen semainseicteeenG eas See 22
Rainey, WG. oNomine shells: bys. hoe tc sh. at sas Ast cen cee Come ee es 36
Ny Orks.00 BUGIS © 0-5-2 mec s'2 So caeas Sao Sotelo ee eee oe ee meee 22
Books received from South Carolina and Alexandria....-..........-2.-222-------- 80
Building-stones used in Washington.’ Sets of 2% 2c 5.2.28 cece Secdccewet ccece. oe.
uslc, Mr. «Naming shells thy e622 cseci0 2528-5 bS dees Motels eee ee og 36
Wana) eeity.: telsn tor. inproyan es = 6/255 2b ap Sense c owe lee eect ioc see cee 39
Carpenter, PP. Arrangement and naming of shells, by.........c0-.scee- -socce 36
WW Oris Onrshelistsseess 2205.12 cos Sed an catedet Mc aug kae tasers oneee 22
Catalogue of Transactions, in Smithsonian library.............. 222.2222 22-2 eeeeee 42
Catalogues of libraries. On construction of. .... 2.222. 0.2.22 sces seed eeen eens cess 416
Carlyhie Horce:- Avmemoing by; D0. Phipson 26 42 dood Le Se cee ak wt 395
Chester county. Notices.of men.and events in ...<.. 5. -i2sc2cceecciscs cane chenids 83
Circular to telegraph operators relative to observing the weather ...............---- 81
Wivil Hngineérs.: -Prize.questions ic. <= cc en estes ccna fut Sees ws ss 430
Classification of ‘books; by: John -P: Wesley soc. oaks 3 NSO esos k coon 416
Cleveland, Prof. Parker. Meteorological record from 1808 to 1859 .............2--- 30
Coast Survey. Tables computed at, for Smithsonian..............22222.-..22020- 25
Collections of, Natural Mistorys> Account of. {2220 l.oe e be o ces ke 3
Comets. iiveshigationsyrelative toms 5 seul eeeee ee ef ee ee: 82
Conchology. Smithsonian publications on.... 2... 2... -c0.neos cone cone cccccccces 21

442 INDEX.

Page.
Congress. Appropriation by, for care of collections ..... MEE MUO sin tesaetee a 77
Contact, phenomena of. Memoir on....--..---- +--+ +--+ 20+ + eee eee eee eee eee 395
Contributions to knowledge. Contents of vol. XIII.-..---.----------------++---- 17
Correspondence. Extracts from...-...----------+----+- ++ 2-+ reece cere ee eens 80
Cycladide. Prime's work on ..--...-.----+++--+2---- eee eee ee erence reer eee 23
Daa, Louis Kr., museum in Christiania, Norway--.-.-.--------------------------- 85
Darlington, Dr. Wm. Work presented by..-------------+----++ +--+ +-+--2----+- 383
Death, Of 5 stesso store sivstetie le Srey ol = olen a la se She aoe elie 83
Davis, Hon. G. Appointed regent, to succeed Mr. Pearce ....---.---------------- 78
Deaths of meteorological observers - ------------ ---- +--+ +--+ -2ere+ eee ee rere eee 69
Dille, I. Letter of, relative to archeology .....-----------------+---------------- 86
Disinfectant, made for hospitals .----------------------+---+----------+-++-------- 38
Distribution of specimens. Rules for-.-.---.------------++----+-+-----+--+------- 35, 36
Donations to the museum in 1862. -....-----------------------+----------- +--+ eee 57
Eaton, Daniel C. Letter relative to ferns -----..------------------------ eae eee 97
Egleston, Th. Arrangement of rocks and minerals by, and list of species .-....---- 36
Engelmann, Dr. Geo. Heights of mountains --....--------------------+-------- 81
Entomology. Smithsonian works on ---.-.----------------++++--++-----+----+---- 24
Specimens referred to collaborators ------.---------++----+---+-++-++++-- 37
Estimates for 1863 .----------- ----- +--+ = ene ee ne ens ce een nne corte ne cone ceeeee 77
Ethnology. Lectures on, by A. Morlot..-...-------------+----------- ae eee 303
Lectures on, by Prof. D. Wilson -....------------------------------ 240
Eulogy on Hon. James A. Pearce, by Prof. Bache -.--------------------+--+----- 100
Exchanges. Literary and scientific. -...-.--.------ +--+ + +++ +++ e+e esse eee cree eee 4}
Exchanges. Statistics of..---..--------- +--+ -- +--+ ee ce eee ree cree eee cece eee ee 47
Expenditures of the Institution during 1862 .-..----------------+ +--+ 22-2 reese aT
Explorations for the Institution. ...----..--.-------- +--+ +--+ 2-2-2 ee eee eee eee 39, 55
Ilachenecker, Geo. Letter relative to Sheyenne Indians ....-....---------------- 95
Fladgate, Clarke & Finch, attorneys to collect remainder of Smithsonian fund in
Buigland. 2.22. 3-502 -22 ooe Steno eee ney e one ae ie ae Sone oe ia arte 15
Force, W. Q. Meteorological system, in charge of....--...---.---------+------+-- 32
Observations on temperature of hydrant water -.--------------------- 30
Foreman, Dr. BE. Setsof Unionidee, by -----..----..---2- --2--- e222 epee 56
Flourens. History of Academy of Sciences of Paris..-.----.--------------------- 337
Memoir ‘of Leopold Von Bach’ 1l 2. oi. oe icc ee ewes sence 358
Memoir of Louis Jacques Thenard -:- 2-22.22 0 od ees anes 373
French, B. B.- Grounds under the care of. ......------------ 2252+ oes eee eee 38
Gallery of art. Additions to-.----------------------- +--+ +--+ 0-222 eee ee eee eee 42
Gibbs, Geo. Letters on philology and ethnology .--..-.-----.----------- 87,89, 91, 92, 93
Gill, Theo... Examination of fishes. ..--2----2-0 02-22 see ee een e eee deeb eee eee 56
Girard College. Prof. Bache’s observations at-....-..--.----5--------------- Rect 17
Government. Aid rendered to, by the Institution ..---.-...----------------+----- 14
Gray, Dr. A. Arrangement of plants, by--------.-2-- --- 222+ sense see ose eee ones 36
Gray, Dr. J. E. Identification of bat .------+-+- +424, ses2 +e 2s eee ee cee eee see e ee 96
Guyot, Prof: A. Extension of tables of. .....----. -+-----2++ t2-222 e222 ee ese eeee 3]
New. physical tables. ... .-.<- s<--2=js6 0 cnnisenmesen-4--he-h- ies -=-- 25
On. Parry’s, mountain measurements.» —j.2,-r\- = =)-on ae aie ee <== 82
Relation of standard barometers, established by ..---.----------+----- 31
Hammond, Dr. W. A. Interes# of, in meteorology....-» ------ «----- «=-<ie- -¥---- 33
Haven, S. F. Archeology of United States, review of....-....----.------------- 318
Herbarium received from ‘Tennessee. = «225 = j cso singe masse nina ee ne 96
iEloxschel’ Sir John. ‘On Atomsio sce .c ce cise aicintotetsio erento ote tel etelaatele aotearoa aie 413

INDEX. 443

Page.

Hildreth, Dr. 8. P. Meteorological records of ...-.......-- St) eile manhole amie, sek 31
Historical sketch of Academy of Sciences of Paris, by Flourens........---...------ 307
Honorary members of the Institution... - ~ 235 ses are jem ptmrlerie sompiaripc eee oriemenice 6
Hubbard, J. S. Investigation of Biela’s comet...-.. «~~~. sence werneetisccememeen 82
Mudson’s Bay Company. Facilities rendered by, to Mr. Kennicott..-.-..-.-- eae 40, 50
Humaniremains from’ Patagonia. Account Of; <2 sooo ho oe sm npc meine maine 5 -'d= pian 426
Tmgonien Calises Of TCCUCHION Of. cece secice v= emert seman oes ent ames a2 sateen tea ne 15
Statementror ior leos -ascttects an oie aa-feeecienicscs she ceie nit aaene Saal 75
Peidexatomecitress On lio lus meets eile ctere le eter ae a nial eee eens aimee ietcro einer a oie 232
indiana. ‘interest wou recerved! OM DONGS Of. .' 2.2 os oo see teas 22 gone scans en asiec as 15
Ynstitutions sending meteorolopicalrepisters -< -- 2 22 one ome gece ns cone enn ne == 69
Johns, Bishop John. Books of, sent to Smithsonian by War Department....-.-..-- 80
Journal of proceedings of the Board of Regents... ~~ .-.s.- ccc csecec eee ces se eee 78
Hennicott, Robert: Account of exploration Of- 2.222 .- oo-y emcewetace es oneces ona. - 39, 55
Labarraque’s disinfeeting liquid 2222. 2.22.2 25 - ao - 8 ~ nese nne nnn cme scs apenercown an 33
Laboratory. Operations i: - 5522. 6.2 Sse fo coe. case ncise secs Jeectd coe cee ce nees wane 33
Lapham, I. A. Antiquities of Wisconsin, review of.---...----. ..-2-5. 2222. ~.---- 318
Lawrence, George N. Labelled humming birds.---.. 2222 2522-020 ebscee eee 59
Pabranes., Classitication.al DoOKs}In 22. acmawiacinae slomcines wineinin aicalesiviniseieine nee < 416
PA TAl ye sev CIONS’ 10s sss s Jaca ae) Sasar emcee sect eens Eee eee oeae ee sce = 41
bepht: -bhectures.on:the, wndulatory theory, of:=:2-<.-sense sacsceceeacoctes > -oanee 107
Som Inage.; « Naming shells; sry ss iscs.cccscccasancae sos acleneetw eoasr ee ements tee 36
Mectutes:.. Accountiol, durine 186162 52s sce sceressninwe ni oamecilsceseaa eee cici= sa 43
Rules G0) POVEIN, 555. 2.23 -ns- Sees win wale siesioteinee aciels aecimienen essere 44

Mist of delivered 1862635202 .sssaeersacistees eS ee eeeisctu ns oe 45

On the study of high antiquity, by A. Morlot ..:.2.. 00.52. 22. s.sece- 303
Onvethnolocy; by, Professor DANWWilsOne ase acne ae sine eee ole eeiciere soak = 240

On the undulatory theory of light, by F. A. P. Barnard..........-..-- 107

Wesley, coun 2. “Onithe classification of books: -: .- 2. - occ Soc oas once seicccstacess 416
MER ULET Steen SOCIOL Yai O.ONOTCSS taal pate ainin'ny ctniiniarel sae eens ninis ott aleteleyalcie/otete a lehelale a2) 3
Chancellor and Secretary to.Congress:. 055.2. oso jcc Sie cote wwe 4

H. Sibley, relative to telegrams of weather. ......-.-2.. -.-- 22-02 e--0 81

G. Engelmann, relative to Dr. Parry’s barometrical measurements... -.--. 81

J.S. Hubbard, relative to observations of Biela’s comet.....-...----- 82

William Darlington, relative to notices of men of Chester county, Penn- 83

T. Lyman, relative to Schlagintweit’s collections........-.-.---------
H. de Schlagintweit, relative to collections of ethnology, &c., for sale... 84

Louis Kr. Daa, relative to ethnological museum at Christiania, Norway. 85
I. Dille, relative to archeological remains ........--2-2s2e-s.e---+ 20s 86
Dr. Aq. Ried, relative to Atacama mummy........-.-.---- (ensote 3 acs fe 87
George Gibbs, relative to philology and ethnology....-...----..-.---- 87, 93
J. G. Shea, relative to Indian vocabularies.----- s.25 cee. eke 94
E. A. Watkins, relative to dictionary of Cree Indians..-....-.-..-..... 94
G. Flackenecker, relative to Sheyenne Indians...-...---...-....----- 95
W. H. Pease, relative to natural history, &c., of Sandwich Islands: ---. 95
Dr. H. R. Wirtz, relative to herbarium captured from confederates. - - --. 96
Dr. G. Mettenius, relative to ferns of Brackenridge’s collection....-.-.-. 97
DC. Eiston; relative: fo-ferns. <u Se. cc cicc.c toca Mae ates anielewincice wines 97
H. de Saussure, relative to works on entomology ..---...-.----------- 97

relative to sale of cabinet of minerals..-..-.--.-.---.- 98

M. Romero, relative to Xantus’s explorations in Mexico..-...--..-.-.- 9g

444 INDEX.

Page
Lewis, Dr. James. Account of meteorological records made by the machine of...--. 32
Lubbock, John. On North American Archaeology ...--..-.2+20---2.s0200+02-000- 313
Liyman, Theo. Recommending Schlagintweit... 2. 0s ocwecnser asennad seedasite de. 84
Mecnetic observations; by Protessor Bache -2 05.05 62c. --cnes cose a eee 17
Magnetic survey of Pennsylvania, New York, Ohio, and Maryland, by Professor
Bache gid Wis Schott! uc waec ve wes wate ss angen aoouliad hs Meee ee Cee 20
MePeals, Walliam. “Death Ofc. 22.20.22 3550 s'esina ns Bacriepet aces oe ae eee 79
Funeral expenses to be paidsiss20202+2s25- nadie ound geese eae ae 79
Melaniadse, . Tryon’s, work on....-2.2.<--- +54 s¢a-ehsawegatt-derd-eemponeah 6s. 23
Members ex officio of the Institution... 6.2.06 - sane case dacdumatienanthenaeiie le sce 6
Memoir of Isidore Geoffroy St. Hilaire, by Quatrefages..-.-.-..2.-2.--+--2-------- 384
Leopold Von Buch, by Flourensjenj.-ctis- demas natisinic wp aseai te ued 308
Louis Jacques Thenard, by Plourende nec peicdiar ride he-iPe rad te eens O73
Meteorological directions and blanks adopted in Mexico...-....--.-..----.-+---.-- 31
Material contributed in addition to regular observations........---.-... 70
Operations in, 1662.5 go Ri ee ete a tale iret ne ae ees 28
Records by. Dr.. James, Lewis 4524: qzesejeciahe sia netnasa etek ARE 32
Stations and observers for 1862... wdreomncdieaiatehimcite > seemathean ary 3 62
System, much deranged by the Warsewe<0satenwieoansinds- sem app sano nin 14
Mettonius, GC... Wetter-relativ.e: to. femnsi-.-ceiserssela esis ante LAdalsed = Canale So cepa ets 97
Minerals,, . Examination Of... o0disccas cancavecdacqebedes sis sasps tp te. .aee 33
CH OTEd LOY BELO) a aie aces wend met nape tas galas Haein aap, Sedera Ene. ee faye 98
Miscellancons.Collections.. . Account .0f .2.< cian oewn'dswnss von ot od ese SUh oes ate 21
Comienta/ of rst. f0Ur VOlumes's 00min tas waco u ielsie Geb ta wan 61
Moon. « Mapmotic. IniUenCecOf—., 2a 0 lee astias) ale = 8 ota alate Salo eae oot aietals amiotette Ree siete ise 20
Moarlot;A.. .bectures on study. of high antiquity s.2. se aecet i> ace wloeal selec ene Lr ous
MinimiGs Tom Pata g OMe sae slg etm als emt gene ale hte caret ae fo eiclaime beetle ara apne ee 426
Museum... “Accdunt and‘ objett of... 2.26 coc seek cancers tence. meee 34, 37
ATTEN OMent OL SPECIMENS I< ain.cm asa aimsatem iain ia sfalele ela fere a helm Sener teeye 56
Instron Gonanions to; Tdi SG Cee we stealec oe aterm stem eee meeete| = ate o7
National Institute. Property transferred to the Smithsonian.........-...-.--.----- 16
NOrwepridn MiUussuint, Cede Olen aass oe lam o-5.-8 2 aide sects mc clceiaieelomio sete ete ara 85
Oiicers, of the Sthithsonian Institatipn. ss i oe ee Sechaba ces some 5
Parry, Dr. Barometrical measurements of mountains -.......-.2. 200222 sce eee ee 81
Patagonia. . Account of buna venainy Mometects-6 tc el. Gece. scenes ce. am eons -~ 426
Irbarce, Tdi, J? At Onno eyaGne A Sess Oe ce 2 setciare oo aiactere elatictaare Ania. 100
Resoltitious Telstive tothe death Or 0s ose ee etal. ates stale Adie ie aa = 78
Pease, W. H.. Letter relative to Sandwich Islands-..20 220. oe kes 95
Phipson, T. L. The catalytic force, or studies on the phenomena of contact... ..-- 395
Pierce, Professor B.”.. Doctrine of probabilitiesue s!5 a se clsas wale Moe atala Le eletale lana « 19
Politics excluded’ from’ operations of Institution. so.) tes ne aso lee se. oo ee 44
Biime; \."" Naming shellatbin S222 35So Sa e tree tana Cares winnie one ae ete Sintes le fetes 36
On gland so eee cee easel Pate Ode aka e baemrewasien yomerane cae 23
Printing by the Institition dhting 1862) 50.8 6 IS. iad ls. see te duce de aswel cameuk 46
Frize questions by scionite adtietles sis Sosa Paes ea elecelaaeees ee 430
Programme of organization ‘of the Institution... 20.5 22.2 5.05 22c eben i. eee t
Of stiontific societies vss el aan ae ace reter Came omen es a eee 430
Provincial Society of Arts and Sciences of Utrecht. Prize questions....-.-..-..-.-- 434
Publicstions. ”.Tist of, during Weses7ers eat eee mevionce cases chen aseainoed 60

ACCOUNT Of ions Ho. cavcce BRS soe cae marets cores eeictene creenetne elena eee 16

INDEX. 445

Page.

Quatrefages. Memoir of Isidore Geoffroy St. Hilaire. .... 2.2.2.2... -22- cee e ene eee 364
Keceipts and expenditures during 1862: 2: Ce 2s2es oe ee OS ee ee oe aid 15
Hegents-of the Smithsonian Institution <== 2: .S20sb2 i027. 2 pee. a 5
Repister Onvisitors =< 2s52ssssssesseegreees esse eet OEE, Ee OU RAG 8 38
Reid, Dr. A. Account of human remains from Patagonia.......----..----------- 426
hetter,-withAtacamta mummy: = 2252222255 225225-53 2222S. 586 Ae Se 87

Eeport-of Regents for 1661, contents-of :22552:2225522525255; Soe 27
Executive: Committees sais 222 cn2 nese, Sh 8s S759 A Fe 75,79

secretary; Prof.» Henrysess 02545, ceeteeere Pee. Be. 13
Eixtrercopies ordered 4-+2.:25.s22tseeteces tPA Gus JO gre 3a 27

‘Hules:for distubution’ of yer sseeaw ae eee ele cee eeee Sores ee ee 28

Resolution of Senate ordering report to be printed... .......---2----- 22+ --0----- 2
Reselutions of Regents relative to appropriations. .....,----------+--------------- 12
Komero; M.~ “Letter pranting facilities to Rantus +02. los. cc cecs cccces oeae core 99
Royal Danish Society of Sciences. Prize questions..-.....2... 222222 -222-- ccecee 436
Royal Society of London. Systematic Index prepared by .----..----------------- 42
Saint Hilaire, Isidore Geoffroy. Memoir of, by Quatrefages...--.........--.------ 384
pausary wonnmission, ~ SciciiiicIHbUrs df -2522%.--.-0-2-~-oc- as-5 eoee roe oe cone 14
Saussure, Henry de. Letter relative to works on Hymenoptera, Orthoptera, &c .... 97
Schlagintweit, Hermann de. Description of collections of ethnography, &c., for sale. 84
SCHEME HAS. Ay) SAONCHC SUTVENS; DY ccssse soc. «nccmecceeccip= cere aewepcercces 20
Shea, J. G. Leiter relative to Indian vocabularies... -- 2.22. 2-2. oe one cw ee en cece 94
Shells of North America. Smithsonian works on ----.--.....-2..-2--0---ee--esce 21
Ebley, urem.. Ueleprapnic 'C0-OpelailOl.: -.s< canes etn eicanionecincpemdemecswnms 80
Silliman ioe reseritiote PUBL Olee. “eat acta as naan cae ee cnlocenesenenic teen ene 43
Sleckam Dr ee Catalooteror: Monkeys, DYeeaaioc\-( ate iemn cn iinieisiacnsvenee cecm|ose sieeacee 55
Squier, E. G., on aboriginal monuments of N. Y. Review of -......-.-....--.-..- 318
Bameiine avis WOVIOW OL =< sccm occ sacue sneer ee cee aa te on eee on ee oieaetetesters 318
eager, 8.0, Lelectanis of weatler {f0M - . =< aap ariein nico cop epeehecsecs <a epee ss 29
stanley, J. M. Indian gallery of -...-------- 2-22 0- +222 ee 00 cone eee eee ene eee 43
Stanton, E. M. Communication from, relative to books from South Carolina -...--- 80
Precusicnp, A0%. INGUIN SHOU DY) =o animate wines aim ye mete ela sine sd tin as hs niciy abated 36
Stereotyping publications of Smithsonian ...-. 02. <c00.<200,0-0- --=-ser- cen -mn ores 28
BesRIED RO. SVN Gas CNET SONG: Dire se ete mia niin wine eee a on ec adn oni eee 36
@nisnells:of the east. Coast U. Oceana cco. scocen case pelea clan eee 23

Studies on the phenoniena of contact, by T. L. Phipson ...-...--.-...---- -------- 395
Ppner: oy Mi ti.) ust Ol; PICSCHICN : oc ree cremin ema coer 6 oo ricck<-aeneas ee ene 3
yi» NIA ONC COMUNERCS Olea epee aceon ac Hemmann sasas nee pcieeninah hans a= keels 19
Surgeon General. Co-operation in meteorology... 22 2-0-2 -+ nnn ccs oct aecennees 33
SClenistie; lah OTs Obese setae a aele oer eas wie See ee iectineen had es 14

Systematic Index to articles im transactions. -... <2. ..6< cc ceo cewe o sin clone naiceas el ct 42
Tables. Account of new series of, prepared by Prof. Guyot ..---..---..-...-----. 25
Telegraphers. Directions to, relative to meteorology ...-- .-.- o0--sereneasence case 81
M@ieleprannic, Dalle Gt WeAlHer <p. oo mcm on wniem oe monn ep tan aie rete ce nian 29
Pomperature.. Underpround - 22. ..52 252-2) sons epee tenss aetetian da ben dinten =r nnee 30
hanks tor transporailon: COMPANIES! .<\- = <s[n,ciemic ocice sla pirate nem nisin isco/eee eos 41,47
Thenard, Louis Jacques... Memoir of, by Flourens..... 222-22. oco0en-- cncecacces 373
Homey, Dr J. vArrancementiof plants, Dyjoac~ s< em oeee each epee ce ae apese 36
Tornadoes. Circular relative to and information obtained respecting .......-.-.-..- 29

Transportation. Details Of... .--------- coc- coce cee cee ncen cee cee cece ccceee 47

446 INDEX.

f Page.
Tryon, G. W. Naming shells, by------------------ +++ eee eee coos cece eeee ee eee 36
University of Michigan. Contributed to Kennicott’s exploration -...-....--..----- 40
Von Buch, Leopold. Memoir of, by Flourens--.-...--.------------------------- 358
Wallach, Hon. Rich., appointed on Executive Committee. ..---.-.----..----------- 79
War, Department of, communication from, relative to books from South Carolina and
Blairtavx SEMIN a Rye se assis ta os Ahn a ote a alee) tarot elmer alana ae to alate 80
War, ‘liifectiof on scienGetsss2 3 +3 sas asada tase nee San ee eae etalon e tts 13
Watkins, E. A. Letter relative to dictionary of Cree Indians Bee PTO IIIS SS ierne 94
Wilson, Prof. Daniel. Lectures on Physical Ethnology .--.------------------+--- 240
Wirtz, H. R. Letter relative to herbarium-.-...----.----------------+------------ 96
Wood, Geo. Present of bust of W. H. Sumner from .....----------------------- 43
Xantus, John. Explorations in Mexico. ..-.-.----- --------++ ---+ --- 2 eee e eee eee 40, 55
Facilities to, granted by Mexican government... .... seueeeee ee cer stseet 99

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i PP Cate Sa ean Pee Io a STS ere ; es = Ks ee pee ae
Seana Snes Sees te ee ROAR se eee go 2 ae Se occa res a en RO
Sore Sa ae eae —— Pees Soin Tencyeares os o om os oe oe Se oe Ne 5
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a Rs eee aoe oe ees o - oat - x Scone a Ramee ate
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