A MEMOIR

OP

JOSEPH HENRY.

A SKETCH OF HIS SCIENTIFIC WORK.

BY

WILLIAM B. TAYLOE,

Read before the Philosophical Society of Washington,

October 26th, 1878.

PHILADELPHIA:
COLLINS, PRINTER, 705 JAYNE STREET.

1879.

V

^: ^

SMITHSONIAN INSTITUTION

A MEMOIR

OF

JOSEPH HEJ^RY.

A SKETCH or HIS SCIENTIFIC WORK.

BY

WILLIAM B. TAYLOE.

Read before the Philosophical Society of Washington,

October 26th, 1878.

PHILADELPHIA:
COLLINS, PRINTER, 705 JAYNE STREET.

1879.

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A MEMOIR OF JOSEPH HENRY.

[FROM THE BULLETIN OF THE SOCIETY. VOL. IL]

( 3 )

230 BULLETIN OF THE

A MEMOIR OF JOSEPH HENRY.

A SKETCH OF HIS SCIENTIFIC WORK.*

To cherish with affectionate regard the memory of the venerated
dead is not more grateful to the feelings, than to recall their ex-
cellences and to retrace the stages and occasions of their intel-
lectual conquests is instructive to the reason. I'ew lives within
the century are more worthy of admiration, more elevating in
contemplation, or more entitled to commemoration, than that of
our late most honored and beloved president — Joseph Henry.

Distinguished by the extent of his varied and solid learning,
possessing a wide range of mental activity, so great Avere his
modesty and self-reserve, that only by the accidental call of
occasion would even an intimate friend sometimes discover with
surprise the fulness of his information and the soundness of his
philosophy, in some quite unsuspected direction. Remarkable
for his self-control, he was no less cliaracterized by the absence
of self-assertion. Ever warmly interested in the development
and advancement of the young, he was a patient listener to the
trials of the disappointed, and a faithful guide to the aspirations
of the ambitious. Generous without ostentation, he was always
ready to assist the deserving — by services — by counsel — by active
exertions in their behalf.

In his own pursuits Truth was the supreme object of his re-
gard,— the sole interest and incentive of his investigations; and
in its prosecution he brought to bear in equable combination
qualities of a high order; quickness and correctness of percep-
tion, inventive ingenuity in experimentation, logical precision in
deduction, perseverance in exploration, sagacity in interpreta-
tion, f

* A large portion of the following disconr^e (iueluriing nearly tliR wliol^
of the section on the "Administration of the Smithsonian Institution,")
was necessarily omitted on the occasion of its delivery.

t Henry's tribute to Peltier, seems peculiarly applicable to himself.
•'He possessed iu an eminent degree the mental characteristics necessary
for a successful scientific discoverer; an imagination always active in
suggesting hypotheses for the explanation of the phenomena under inves-
tigation, and a logical faculty never at fault in deducing consequences
from the suggestions best calculated to bring them to the test of experi-

4

PHILOSOPHICAL SOCIETY OF WASHINGTON. 231

EARLY CAREER.

Of Henry's early struggles, — of the youthful traits which might
afford us clue to "his niauhood's character and successes, we have
Imt little preserved fur the future biographer. Deprived of his
father at an early age, he was the sole care and the sole comfort
of his widowed mother. Carefully nurtured in the stringent
principles of a devout religious faith, he adhered through life to
the traditions and to the convictions derived from his honorable
Scottish ancestry.

As a youth he was by no means precocious, — as seldom have
been those who have left a permanent influence on their kind.
He seems to have felt no fondness for his early schools, and to
have shown no special aptitude for the instructions they afforded.
Like many another unpromising lad, he followed pretty much his
own devices, unconcerned as to the development of his latent
capabilities. The books he craved were not the books his school-
teachers set before him. The novel and the play interested and
absorbed the active fancy naturally so exuberant in youth ; and
the indications from his impulsive temperament were that he
would probably become a poet — a dramatist — or an actor.

He was however from his childhood's years a close observer —
both of nature, and of the peculiarities of his fellows : and one
characteristic early developed gave form and color to his mental
disposition throughout later ^ears, — an unflagging energy of
purpose.

About the year 1814, while a boy of still indefinite aims and
of almost as indefinite longings, having been confined to the
house for a few days, in consequence of an accidental injury, his
restless attention happened to be drawn to a small volume on
Natural Philosophy, casually left lying on a table by a boarder in
the house. Listlessly he opened it and read. Before he reached
the third page, he became profoundly interested in the statement
of some of the enigmas of the great sphinx — Nature. A new
world seemed opening to his inquisitive eyes. Eagerly on he
read, — intent to find the hidden meanings of phenomena which
hitherto covered by the "veil of familiarity" had never excited a
passing wonder or a doubting question. Was it possible ever to
discover the real causes of things? Here was a new Ideal — if
severer, yet grander than that of art. He no longer read with the
languid enjoyment of a passive recipient; he felt the new neces-
sity of reaching out with all the faculties of a thinker, with all the

ence ; an invention pverfertilf in devisincr apparatus anil otlipr mean* hv
which tlie test could be applied; and finally a moral cnnstittition which
.'sought only the discovery of truth, and could alone be satisfied with its
attainment." {Smithsonian Report for 1867, p. 158.)

5

232 BULLETIN OF THE

activity of a co-worker.* For the first time he realized (though
with no conscious expression of the thought) that there is — so to
speak, — an imagination of the intellect, as well as of the emotional
soul ; — that Truth has its palaces no less gorgeous — no less won-
derful than those reared by fancy in homage to the Beautiful.

The owner of the book observing the close application of the
boy, very kindly presented it to him;f and the thankful receiver
many years afterward placed upon the inside of its front cover,
the following memorandum : —

"This book although by no means a profound work, has under
Providence exerted a remarkable influence on my life. It acci-
dentally fell into my hands when I was about sixteen years old,
and was the first book I ever read with attention. It opened to
me a new world of thought and enjoyment; invested things before
almost unnoticed, with the highest interest; fixed my mind on
the study of nature ; and caused me to resolve at the time of
reading it, that I would immediately commence to devote my life
to the acquisition of knowledge. J. H."

The new impulse was not a momentary fascination. Thence-
forvvai-d the novel was thrown aside, and poesy neglected; though
to his latest day a sterling poem never failed to strongly impress
him. As it dawned upon his reason that the foundation of the
coveted knowledge must be the studies he had thought so irk-
some, he at once determined to repair as far as possible his loss of
time, (being then an apprentice to his cousin John F. Doty, a
Watch-maker and Silver-smith in Albany,) by taking evening
lessons from two of the Professors in the Albany Academy;
applying himself diligently to geometry and mechanics. And
here shone out that strength of will which enabled him to rise
above the harassing obstacle of the res angusta domi. With the
consent of his employer, so soon as he felt able, (although yet a
mere boy,) he managed to procure a position as teacher in a
country school, where for seven months successfully instructing
boys not much younger than himself, in what he had acquired,
he was enabled by rigid economy to take a regular course of
instruction at the Albany Academy. Again returning to his
school-teaching, he furnished himself with the means of complet-
ing his studies at the Academy ; tvhere learning that the most
important key to the accurate knowledge of nature's laws is a

* "There is a great difference between reading and study, or between
the indolent reception of knowledge without labor, and that effort of mind
which is always necessary in order to secure an important truth and
make it fnllv onr own." J. Henry. {Agricidlural Report of the Patent
Office, for 1857, p. 421.)

t The title of this book is "Lectures on Experimental Philosophy, As-
tronomy, and Chemistry: by G. Gregory, D.D., Vicar of West-ham."
12mo. London, 1808. The owner of the book was a youns: Scotrhmnn
named Robert Royle ; who was one of the boarders at his mother's houae
in Albany, N. Y.

6

PHILOSOPHICAL SOCIETY OF WASHINGTON. 233

familiarity with the logical processes of the higher mathematics,
he resolutely set himself to work to master the intricacies of the
differential calculus.

Having finished his academic course and passed with honor
through his examinations, he then through the warm recommen-
dation of Dr. T. Romeyn Beck — the distinguished Principal of
the Academy, obtained a position as private tutor in the family
of General Stephen Van Rensselaer* As this duty did not exact
more than about three hours a day of his attendance, he applied
his ample leisure (having in view the medical profession) — partly
to the assistance of Dr. Beck in his chemical experiments, and
partly to the study of Anatomy and Physiology, under Doctors
Tully and Marsh.

His devotion to Natural Philosophy which had only grown and
strengthened with his own growth in knowledge, led him con-
stantly to repeat any unusual experiment as soon as reported in
the foreign scientific journals ; and to devise new modifications
of the experiment for testing more fully the range and operation
of its fundamental principles.

Communications to the Albany Institute. — The "Albany In-
stitute" was organized May 5th 1824, by the union of two older
Societies; with General Stephen Van Rensselaer as its Presi-
dent :f and young Henry became at once an active member:
though with his modest estimate of his own attainments, he
preferred the part of listener and acquirer, to that of seeming
instructor, till urged by those who knew him best to add his
contributions to the general garner.

Henry's first communication to the Institute was read October
30th 1824 (at the age of about twenty-six years) and was "Ou
the chemical and mechanical effects of steam : with experiments
designed to illustrate the great reduction of temperature in steam
of high elasticity when suddenly expanded. "| From the stop-
cock of a strongly made copper vessel in which steam could be
safely generated under considerable pressure, he allowed an occa-
sional escape ; and he showed by holding the bulb of a thermo-
meter in the jet of steam, at a fixed distance (say of four inches)
from the orifice, that as the temperature and pressure increased
within the boiler, the indications of the thermometer without
grew lower; — the expansion and consequent cooling of the escap-

* Presiding Officer of the original Board of Trustees of the Albany
Academy.

t The Albany Institute resulted from the fusion of "The Society for tlie
Promotion of Useful Arts in the State of New York," organized Feb. 1791
(incorporated April 2nd 1804,) and the "Albany Lyceum of Natural His-
tory" formed and incorporated April 23rd 1823 : of which latter society,
Henry had been a member.

X Trans. Albany Inst. vol. i. part 2, p. 30.

7

234 BULLETIN OF THE

ing steam under great pressure, increasing in a higher ratio than
the increased temperature required for the pressure. And finally
lie exhibited the striking paradox, that the jet of saturated steam
from a boiler will not scald the hand exposed to it, at a prescribed
near distance from the try-cock, provided the steam be sufficiently
hot.*

Prolific and skilful in devising experiments, Henry delighted
in making evident to the senses the principles he wished to im-
press upon the mind. Extending the law of cooling by expansion,
from steam at high temperatures, to air at ordinary temperatures,
his next communication to the Institute (made March 2nd 1825,)
was "On the Production of Cold by the Rarefaction of Air."
As before, he accompanied his remarks by several characteristic
exhibitions.

"One of these experiments most strikingly illustrated the great
reduction of temperature which takes place on the sudden rare-
faction of condensed air. Half a pint of water was poured into
a strong copper vessel of a globular form, and having a capacity
of five gallons; a tube of one-fourth of an inch caliber with a
number of holes near the lower end, and a stop-cock attached to
the other extremity, was firmly screwed into the neck of the
vessel ; the lower end of the tube dipped into the water, but a
number of the holes were above the surface of the liquid, so that
a jet of air mingled with water might be thrown from the foun-
tain. The apparatus was then charged with condensed air, by
means of a powerful condensing pump, until the pressure was
estimated at nine atmospheres. During the condensation the
vessel became sensibly warm. After suffering the apparatus to
cool down to the temperature of the room, the stop-cock was
opened: the air rushed out with great violence, carrying with it
a quantity of water, which was instantly converted into snow.
After a few seconds, the tube became filled with ice, which almost
entirely stopped the current of air. The neck of the vessel was
then partially unscrewed, so as to allow the condensed air to rush
out around the sides of the sci-ew: in this state the temperature
of the whole interior atmosphere was so much reduced as to
freeze the remaining water in the vessel. '"f

Although the principle on which this striking result was based
was not at that time new, it must be borne in mind that this

* While it requires a beat of 2.500 F. to generate a steam-prpssnre of two
atmospheres ()'. e. one additional to the existing), 25° hieherwill produce
a pressure of three atmospheres, and lOOO higher, (or 3550 p.) will produce
a pressure of nine atmospheres: the curve (by rectangular co-ordinates
of temperature and pressure) resembling a hyperbola. The increased
velocity at high pressure produces a molecular momentum of expansion
carrying the rarefaction beyond the limit of atmospheric pressure ; and in
the case of the exposed hand, the injected air current doubtless adds to
the cooling impression.

t Trans, Albany Inst. vol. i. part 2, p. 33.

8

PHILOSOPHICAL SOCIETY OF WASHINGTON. 235

particular application, thus publiclj' exhibited, was long before
any of the numerous patents were obtained for ice-making, not a
few of which adopted substantially the same process.

State Appointment as a Civil Engineer. — Through the friend-
ship and confidence of an influential judge, Henry received about
this time an unexpected offer of an appointment as Engineer
on the survey of a route for a road through the State of ^"^ew
York, from the Hudson river on the east, to lake Erie on the
west. The proposal was too tempting to his natural proclivities
to be refused; and being appointed, he embarked upon his new
and arduous duties with the zeal and energy which were so pro-
minent a feature of his character. He completed the survey with
credit to himself, and to the entire satisfaction of the Commis-
sioners of the work.*

So attractive appeared the profession of engineer to his enter-
prising disposition, that he was about to accept the directorship
in the construction of a canal in Ohio, when he was informed
that the Chair of Mathematics in the Albany Academy would
soon become vacant, and that his own name had already been
prominently brought forward in connection with the position. At
the urgent solicitation of his old friend and former teacher Dr. T.
Romeyn Beck, he consented with some hesitation to signify bis
willingness to accept the vacant chair if appointed thereto.

Election as Professor of Mathematics. — In the spring of 1826,
Henry was duly elected by the Trustees of the Albany Academy
to the Professorship of Mathematics and Natural Philosophy in
that Institution. As the duties of his office did not commence
till September of that year, he was allowed a practical vacation of
about five months; which was partly occupied with a geological
exploration in the adjoining counties, as assistant to Professor
Eaton, of the Rensselaer School, and partly devoted to a conscien-
tious preparation for his new position.

In a worldly point of view, this variety of occupation and ver-
satility of adaptation might perhaps be regarded as unfavorable
to success. As a method of culture, it was of unquestionable
advantage to his intellectual powers. A hard student, with great
capacity for close application, he accumulated large stores of in-
formation: and in addition to his constant thirst for acquirement
in different directions, his leisure was occupied to a considerable
extent with physical and chemical examinations. On the 21st of
March 1827, he delivered before the Albany Institute a lecture
on "Flame," accompanied with experiments. f

* In a popular jnuvtial (" Thp Eelectio Magazine") it is stated : " His
labors in this work were pxceedinetly arduous and responsible. Thsy ex-
tended far into the winter, and the operations were carried on in some
instances amid deep snows in primnval forests."

t Trans. Albany Inst. vol. i. part 2, p. 59.

9

236 BULLETIN OF THE

Meteorological Work. — The Regents of the University of the
State 0^ New York, endowed by the State Legislature with su-
pervisory functions over the public educational institutions of the
State, in 1825 established a system of meteorological observation
for the State, by supplying to each of the Academies incorporated
bv thera, a thermometer and a rain-gauge, and requiring them to
keep a daily register of prescribed form, to entitle them to their
portion of the literature fund of the State. In 182T, the Hon.
Simeon De Witt, Chancellor of the Board of Regents, associated
with himself Dr. T. Romeyn Beck and Professor Henry of the
Albany Academy, to prepare and tabulate the results of these
observations. The first Abstract of these collections (for the
year 1828) comprised tabulations of the monthly and yearly
means of temperature, wind, rain, etc., at all the stations, an
account of meteorological incidents generally, and a table of
"Miscellaneous Observations" on the dates of notable phases of
organic phenomena connected with climatic conditions. These
annual Abstracts, to which Henry devoted a considerable share
of his attention, were continued through a series of years and
were published in the "Annual Reports of the Regents of the
University to the Legislature of the State of New York.* The
third Abstract (for 1830) includes an accurate tabulation by
Henry of the Latitudes, Longitudes, and Elevations of all the
meteorological stations; over forty in number.

ELECTRICAL RESEARCHES AT ALBANY; FROM 1827-1835.

Of Henry's distinguished success as a lecturer and teacher,
in imparting to his pupils a portion of his own zeal and earnest-
ness in the pursuit of scientific knowledge, as well as in winning
their affection and in inspiring their esteem, it is not designed
here to discourse ; but rather of his solitary labors outside of his
professional occupation in communicating and diffusing knowl-
edge. Very shortly after his occupation of the academic chair
of mathematics and physics, he turned his attention to the ex-
perimental study of that mysterious agency — electricity. Profes-
sor Schweigger of Halle, had improved on Oersted's galvanic
indicator (of a single wire circuit) by giving the insulated wire a
number of turns around an elongated frame longitudinally enclos-
ing the compass needle, and by thus multiplying the effect of the
galvanic circuits, had converted it into a real meai^uring instrn-
ment — a " galvanometer, "f Ampere and Arago of Paris, develop-

* Reports of Regents, &c. Albany, vol. i. 1829-1835.

t The name of (ralvani (as oritjinal discoverer of chemico-electricity)
is usually retained to desigmte both the current and its generator; al-
though the chemico-electric pile and battery were reallj' first courived by
Volta in 1800. In the same manner Oersted is generally accounted the
discoverer of electro-magnetism, although he never devised an electro-

10

PHILOSOPHICAL SOCIETY OF WASHINGTON. 231

ing (Ersted's announcement of the torsional or equatorial reaction
l)etwcen a galvanic conductor and a magnetic needle, had found
that a circulating galvanic current was capable not only of de-
flecting a suspended magnet, but of generating magnetism — per-
manently in sewing needles, and temporarily in pieces of iron
wire, when placed within a glass tube around which the conjunc-
tive wire of the battery had been wound in a loose helix ; and had
thus created the " electro-magnet."* The scientific world was just
aroused to the close interrogation of this new marvel, each ques-
tioner eager to ascertain its most efficient conditions, and to in-
crease its manifestations. William Sturgeon of Woolwich, Eng-
land, had extended the discoveries of Ampere and Arago, by
dispensing with the glass tube, constructing a "horse-shoe" bar
of soft iron (after the form of the usual permanent magnet) coated
with a non-conducting substance, and winding the copper conjunc-
tive wire directly upon the horse-shoe ; and had thus produced the
first6;^czen^ electro-magnet ; — capable of sustainingseveral pounds
by its armature, when duly excited by the galvanic current. He
had also greatly improved lecture-room apparatus for illustrating
the electro-magnetic reactions of rotations, etc., (where a perma-
nent magnet is employed) by introducing stronger magnets, and
thereby succeeding in exhibiting the phenomena on a larger
scale, vvith a considerable reduction of the battery power. f

Faraday had not yet commenced the series of researches which
in after years so illumined his name, when Henry published his
first contribution to electrical science, in a communication read
before the Albany Institute, October 10th, 1827, "On some Modi-
fications of the Electro-Magnetic Apparatus." From his experi-
mental investigations he was enabled to exhibit all the class
illustrations attempted by Sturgeon, on even a still larger and
more conspicuous scale, with the employment of very weak magnets
(where required), and with a still further considerable reduction
of the battery power. These quite striking and unexpected results
were obtained by the simple expedient of adopting in every case
where single circuits had previously been used, the manifold coil
of fine wire which Schweigger had employed to increase the sen-
sibility of the galvanometer. He remarks : —

magnet ; and appears not to have been the first even to dir^cover the
directive influence of a current on a magnetic needle.

* Annales fie Chimie et de Phijsiq>'e, 1820, vol. xv. pp. 93-100.

f Trans. Soc. Eiiconrafjement Arts, etc., 1825, vol. xliii. pp. 38-52.
This battery (of a single element) consisted " of two fixed hollow concen-
tric cylinders of thin copper, having a movable cylinder of zinc plact^d
between them. Its superficial area is only 130 square inches, and it
weighs no more than 1 lb. 5 ozs." Mr. Sturgeon was deservedly awarded
the Silver Medal of the Society for the Encouragement of Arts, etc., " for
his improved electro-magnetic apparatus." Described also in Thomson's
Annals of Philos,, Nov. 1826, vol. xii., new series, pp. 357-3ul.

11

238 BULLETIN OF THE

" Mr. Sturgeon of Woolwich, who has been perhaps the
most successful in these improvements, has shown that a strong
galvanic power is not essentially necessary even to exhibit the
experiments on the largest scale. . . . Mr. Sturgeon's suite
of apparatus, though superior to any other as far as it goes, does
not however form a complete set : as indeed it is plain that his
principle of strong magnets cannot be introduced into every
article required, and particularly into those intended to exhibit
the action of the earth's magnetism on a galvanic current, or the
operation of two conjunctive wires on each other. To form
therefore a set of instruments on a large scale that will illustrate
all the facts belonging to this science, with the least expense of
galvanism, evidently requires some additional modification of
apparatus, and particularly in those cases in which powerful
magnets cannot be applied. And such a modification appears to
me to be obviously pointed out in the construction of Professor
Schweigger's Galvanic Multiplier : the principles of this instru-
ment being directly applicable to all the experiments in which
Mr. Sturgeon's improvement fails to be useful." =*"

The coils employed in tlie various articles of apparatus thus
improved, comprised usually about twenty turns of fine copper
wire wound wnth silk to prevent metallic contact, the whole
being closely bound together. To exhibit for example Ampere's
ingenious and delicate experiment showing the directive action
of the earth as a magnet on a galvanic current when its con-
ductor is free to move, (usually a small wire frame with its
extremities dipping either into mercury cups, or into mercury
channels,) or its simpler modification, the " ring" of De La Rive
(usually an inch or two in diameter and made to freely float
with iis galvanic element in its own bath,) the effect was
strikingly enhanced by Henry's method of suspending by a silk
thread a large circular coil twenty inches in diameter, of many
wire circuits bound together with ribbon, — the extremities of the
wire protruding at the lower part of the hoop, and soldered to a
pair of small galvanic plates ;— when by simply placing a tumbler
of acidulated water beneath, the hoop at once assumed (with a
few oscillations) its equatorial position transverse to the mag-
netic meridian. Bv a similar arrangement of two circular coils
of different diameters, one suspended within the other, Ampere's
fine discovery of the mutual action of two electric currents on
each other, was as strikingly displayed. Such was the character
of demonstration by which the new Professor was accustomed to
make visible to his' classes the principles of electro-magnetism :
and it is safe to say that in simplicity, distinctness, and efficiency,
such apparatus for the lecture-room was far superior to any of
the kind then existing.

* Trans. Albany Institute, vol. i. PP- 22, 23.
12

PHILOSOPHICAL SOCIETY OF WASHINGTON. 239

Should any one be disposed to conclude that this simple ex-
tension of Schweigger's multiple coil was unimportant and un-
meritorious, the ready answer occurs, that talented and skilful
electricians, laboring to attain the result, had for six years
failed to make such an extension. Nor was the result by any
means antecedently assured by Schweigger's success with the
galvanometer. If Sturgeon's improvemeut of economizing the
battery size and consumption, by increasing the magnet factor
(in those few cases where available), was well deserving of
reward, surely Henry's improvement of a far greater economy,
by increasing the circuit factor (entirely neglected by Sturgeon)
deserved a still higher applause.

In a subsequent communication to Silliman's Journal, Henry
remarks on the results announced in October, 1827 : — "Shortly
after the publication mentioned, several other applications of the
coil, besides those described in that paper, were made in order
to increase the size of electro-magnetic apparatus, and to
diminish the necessary galvanic power. The most interesting of
these was its application to a development of magnetism in soft
iron, much more extensive than to my knowledge had been pre-
viously effected by a small galvanic element." The electro-
magnet figured and described by Sturgeon, (in his communication
of November, 1825,) consisted of a small bar or stout iron wire
bent into a U or horse-shoe form, having a copper wire wound
loosely around it in eighteen turns, with the ends of the wire
dipping into mercury cups connected with the respective poles of
a battery having 130 square inches of active surface. This was
undoubtedly the most efficient electro-magnet then in existence.

In June of 1828, Henry exhibited to the Albany Institute a
small-sized electro-magnet closely wound with silk-covered cop-
per wii'e about one-thirtieth of an inch in diameter. By thus
insulating the conducting wire instead of the magnetic bar or
core, he was enabled to employ a compact coil in close juxtaposi-
tion from one end of the horse-shoe to the other, obtaining
thereby a much larger number of circuits, and having each circuit
more nearly at right angles with the magnetic axis. The lifting
power of this magnet is not stated, though it must obviously
have been much more powerful than the one described by
Sturgeon.

In March of 1829, Henry exhibited to the Institute a some-
what larger magnet, of the same character. "A round piece of
iron about one quarter of an inch in diameter, was bent into the
usual form of a horse-shoe, and instead of loosely coiling around
it a few feet of wire, as is usually described, it was tightly wound
with 35 feet of wire covered with silk, so as to form about 400
turns : a pair of small galvanic plates which could be dipped
into a tumbler of diluted acid, was soldered to the ends of the
wire, and the whole mounted on a stand. With these small

13

2-10 BULLETIN OF THE

plates, the horse-shoe became much more powerfully magnetic
liiau another of the same size (and wound in the usual niaunerj
l»j the application of a battery composed of 28 plates of copper
and zinc each 8 inches square." In this case the coil was wound
upon itself.

Hem'y''s "Quantity''^ Magnet compared with MolVs. — Shortly
after this, Dr. Gr. Moll, (Professor of Katural Philosophy in
the University of Utrecht,) having seen in England, in 1828,
an electro-magnet of Sturgeon's which supported nine pounds
irom its armature, " determined to try the etfect of a larger
galvanic apparatus;" and in a paper published in 1830,* re-
marks; "I obtained results which appear astonishing, and are —
as far as the intensity of magnetic force is concerned, altogether
new. I have anxiously looked since that time into different
scientific continental and English journals, without finding any
further attempt to extend and improve Mr. Sturgeon's original
experiment." Moll's horse-shoe formed of a round bar of iron
about 1 inch thick, was about 8 J inches in height, and had a
wrapped copper wire of about one-eighth inch diameter coiled
83 times around it. The weight of the horse-shoe and wire was
about 5 pounds; of the armature, about 1^ pound; and with a
single galvanic pair whose acting zinc surface was about 11
square feet, the electro-magnet supported about 50 pounds. With
cautious additions, the load could be increased to 75 pounds.
An additional galvanic pair of about 6 square feet was applied
without increasing the power of the magnet.f

As soon as the account of Moll's magnet reached this country,
ITenry who had obtained and had publicly exhibited nearly two
years previously, considerably higher results, and who realized
that there was at least one very imjiortant difference of construc-
tion between his own magnet and that of tlie Dutch savant, felt
it a duty at once to publish the details of his own researches, in
a more public form : — which he accordingly did in the January
number of Silliman's American Journal of Science for 1831 ;
(then published only quarterly ;) causing a copy of Professor
^loll's paper, taken from Brewster's Edinburgh Journal of
Science for October 1830, to be inserted in the same number.
At the conclusion of his own article he remarks: "The only
effect Professor Moll's paper has had over these investigations,
has been to hasten their publication : the principle on which
tiiey were instituted was known to us nearly two years since,
and at that time exliibited to the Albany Institute."

The magnet which he had subsequently made, consisted of a
cylindrical bar of iron one-half inch in diameter and about 10
inches long, bent into a horse-shoe and closely wound with several

* Bihlioth^que Uiiirentplle., 1830. cah. 45, p. 19.

f tirewster'd Edinburyh Jour. Sci Oct. 1830, vol. iii. n. s. pp. 209-218.

14

PHILOSOPHICAL SOCIETY OF WASHINGTON. 241

strands of fine silk-covered wire, each about 30 feet long ; which
arrangement when placed in the circuit of a single galvanic pair
whose zinc surface was 6 inches by 4 inches (one-sixth of a
square foot) sustained by its armature " 89 pounds, or more than
fifty times its own weight;" Moll's highest result (of which he
justly felt proud) being only fifteen times the weight of the
magnet, with 11 square feet of zinc surface. While Henry's
magnet had the practical advantage of being about only one-half
the size of Moll's — in each dimension, (and therefore about only
one-eighth its weight without wrappings,) yet it supported more
than half his load : (39 pounds to 15 pounds.) Moll had em-
l)loyed a single copper wire one-eighth inch thick and about 22
feet long : Henry, several strands each about one thirty-sixth
of an inch thick, and 30 feet long; — the former making 83 turns
around the iron core, — the latter, several hundred turns. But
the most surprising contrast resulting from these differences was
the enormous difference of battery-power applied ; Moll pushing
his up to 17 square feet, — Henry reducing his to one-sixth of one
square foot. With a galvanic element reduced to two and a
half square inches, his magnet sustained 28 pounds ; or more
than double the relative duty of Moll's at its highest power.
The philosopher of Utrecht, though he evidently realized with
him of Albany, the importance of close winding, employed but a
single layer of coil. The latter, by means of well-considered trials
had ascertained the great increase of magnetic force resulting
from a succession of coils.

To Henry therefore belongs the exclusive credit of having first
constructed the magnetic " spool" or " bobbin" : that form of coil
since universally employed for every application of electro-mag-
netism, of induction, or of magneto-electrics. This was his first
great contribution to the science and to the art of galvanic mag-
netization. It may be very confidently affirmed that prior to
1829, no one on either hemisphere had ever thought of winding
the legs of an electro-magnet on the principle of the "bobbin";
and that not till after the publication of Henry's method in Janu-
ary of 1831, was it ever employed by any European physicist.

" These experiments conclusively proved that a great develop-
ment of magnetism could be effected by a very small galvanic
element, and also that the power of the coil was materially
increased by multiplying the number of wires, without increasing
the length of each. The multiplication of the wires increases
the power in two ways ; first, by conducting a greater quantity
of galvanism, and secondly, by giving it a more proper direc-
tion ; for since the action of a galvanic current is directly at
right angles to the axis of a magnetic needle,— by using several
shorter wires, we can wind one on each inch of the length of the
VOL. II. — 16 15

242 BULLETIN OF THE

bar to be magnetized, so that the magnetism of each inch will
be developed by a separate wire: In this way the action of each
particular coil becomes directed very nearly at right angles to
the axis of the bar, and consequently the effect is the greatest
possible. This principle is of much greater importance when
large bars are used. The advantage of a greater conducting
power from using several wires might in a less degree be ob-
tained by substituting for them one large wire of equal sectional
area ; but in this case the obliquity of the spiral would be much
greater, and consequently the magnetic action less."* Moll's
single conducting wire of one eighth inch diameter, while there-
fore electrically equivalent to about 20 of Henry's conducting
wires (of the same length and weight) would be magnetically
inferior thereto — for equal iron cores.

Notwithstanding that Henry's successes were thus both earlier
and more brilliant than those of Moll, the two names are usually
associated together by European writers in treating of the deve-
lopment of the magnet, f

Among the subsequent experiments on which Henry was en-
gaged at the time of receiving the Edinburgh Journal of Science
containing Moll's paper, was a series on a much larger magnet,
consisting of a bar of soft iron two inches square (with the
angles rounded) and twenty inches long, bent into a horse-shoe
about nine inches high, and weighing 21 pounds. Its armature —
a piece from the same bar ground to fit truly the ends of the
horse-shoe, weighed 7 pounds. Nine coils of copper bell-wire
each 60 feet in length (making 540 feet in all) were separately
wound on different portions of the horse-shoe. " These coils
were not continued around the whole length of the bar, but each
strand of wire according to the principle befoi'e mentioned, occu-
pied about two inches, and was coiled several times backward
and forward over itself: the several ends of the wire were left
projecting and all numbered, so that the first and last end of
each strand might be readily distinguished. In this manner was
formed an experimental magnet on a large scale, with which
several combinations of wire could be made by merely uniting
the different projecting ends. Thus if the second end of the first
wire be soldered to the first end of the second wire, and so on

* Sill. Am. Jour. Sci. January, 1831, vol. xix. p. 402. The three
names — Arago, Sturgeon, and Henry, may well typify the infancy, the
youth, and the mature manhood of the electro-magnet.

f Faraday in subsequently investigating the conditions of galvanic
induction, referred with approbation to the magnets of Moll and lleniy
as best calculated to produce the effects sought. In constructing liis
duplex helices for observing the direction of the induced current, he
however adopted Henry's method by winding 12 coils of copper wire each
27 feet long — one upon the other. {Phil. Trans. Roy. Soc. Nov. 24,1831,
vol. cxxii. (for 1832,) pp. 12(), and 138. Experimental Researches, etc,
vol, i. art. (J, p. 2 ; and art. 57, p. 15 )

16

PHILOSOPHICAL SOCIETY OF WASHINGTON. 243

thronj^li fill the series, the whole will form a continued coil of
one lung wire. By soldering different ends the whole may be
formed into a double coil of half the length, or into a triple coil
of one-third the length, etc. The horse-shoe was suspended in
a rectangular wooden frame 3 feet 9 inches high and 20 inches
wide."

Two of the wires (one from each extremity of the legs) being
joined together by soldering, so as to form a single circuit of
120 feet, with its extreme ends connected with the battery, pro-
duced a lifting power of 60 pounds. {Ex. 19.) The same two
wires being separately connected with the same battery (forming
a double circuit of 60 feet each) a lifting power of 200 pounds
was obtained: {Ex. 10.) or more than three times the power of
the former case with the same wire. Four wires (two from each
extremity of the legs) being separately connected with the bat-
tery, (forming four circuits,) gave a lifting power of 500 pounds.
{Ex. 12.) Six wires (three from each leg) united in three pairs,
(forming three circuits of 120 feet each,) gave a lifting power of
290 pounds. {Ex. 18.) The same six wires being separately
connected with the battery in six independent circuits, produced
a lifting power of 570 pounds : {Ex. 13.) or very nearly double
that of the same wires in double lengths. When all the nine
wires were separately attached to the battery, a lifting power of
650 pounds was evoked. {Ex. 14.) In all these experiments
"a small single battery was used consisting of two concentric
copper cylinders, with zinc between them : the whole amount of
zinc surface exposed to the acid from both sides of the zinc was
two-fifths of a square foot : the battery required only half a pint
of dilute acid for its submersion."

"In order to ascertain the effect of a very small galvanic ele-
ment on this large quantity of iron, a pair of plates exactly one
inch square, was attached to all the wires : the weight lifted was
85 pounds." {Ex. 16.) This was certainly a very remarkable
result; particularly when compared with Moll's 75 pounds with
eleven square feet of zinc. In order to obtain the maximum
attractive power of this magnet, with its nine coils, "a small
battery formed with a plate of zinc 12 inches long and 6 wide,
and surrounded by copper, was substituted for the galvanic
element used in the former experiments : the weight lifted in
this case was 750 pounds." {Ex. 15.) This is exactly ten times
the maximum weight supported by Moll's magnet with a far
greater battery power. In illustration of the feeble power of the
magnetic poles when exerted separately, it was found that with
precisely the same arrangements giving a holding power of 750
pounds to the double contact armature, — either pole alone was
capable of sustaining only 5 or 6 pounds : "and in this case we
never succeeded iu making it lift the armature — weighing 7

17

244 BULLETIN OF THE

pounds. We have never seen the circumstance noticed of so
great a difference between a single pole and both."

Henry^s " hitensity^' 3Iagnet. — But Henry's remarkable paper
of January 1831 contains still another original contribution to
the theory and practice of electro-magnetics, no less important
than his invention of the magnetic spool. While Moll had
endeavored to induce strong magnetism by the use of a powerful
" quantity" battery, Henry had labored to derive from a mini-
mum galvanic power its maximum magnetizing effect : and in
his varied experiments on these two factors, he discovered very
curious and unsuspected relations between them. A great
majority of investigators — after having definitely ascertained
the striking fact of the great inferiority in magnetizing pov^er,
of a single long continuous coil, to a proportionally shortened
circuit of multiple coils, — would naturally have been led to
abandon all further investigation of the feebler system. Henry
however recognized in this a field of instructive inquiry : and for
the first time showed that the coil of short and numerous circuits,
least affected by a battery of many pairs, was on the contrary
most responsive to a single galvanic element; while the single
extended coil, least influenced by a single pair, v\^as most excited
by a battery of elements. He appears to have been the first to
form a clear conception of the difference between "intensity"
and " quantity " both in the battery and in the magnet : a dif-
ference which (as referred to the current), he was accustomed
figuratively to illustrate by the mechanical difiierence between
equal momentums of high and low velocity.*

The illustrious Laplace had suggested to Ampfere in 1820, —
immediately upon the discovery of the galvanometer, that by
sending the galvanic current through long wires connecting two
distant stations, the deflections of enclosed magnetic needles
would constitute very simple and efficient signals for an instan-
taneous telegraph. f Peter Barlow the eminent English ma-
thematician and raagnetician taking up the suggestion, had
endeavored more fully to test its practicability. He has thus

* " In describing tlie results of my experiments, the terms ' intensity'
and 'quantity' magnets were introduced to avoid circumlocution, and
were intended to be used merely in a technical sense. By the intensity
magnet I designated a piece of soft iron so surrounded with wire that its
magnetic power could be called into operation by an ' intensity' battery ;
and by a quantity magnet, a piece of iron so surrounded by a number of
separate coils that its magnetism could be fully developed by a 'quan-
tity' battery." (Smithsonian Report for 1857, p. 103.) Although these
terms are somewhat antiquated, and repudiated by recent writers, they
will be retained in this Memoir, for their convenience.

f Annates de Chimie et de Physique, 1820, vol. xv. pp. 72, 73. Ampere
made the experiment suggested by Laplace, through a long conducting
wire " with perfect success." The length of the wire is not slated.

18

PHILOSOPHICAL SOCIETY OF WASHINGTON. 245

stated the result: "In a very early stage of electro-magnetic
experiments it bad been suggested that an instantaneous tele-
graph might be established by means of conducting wires and
compasses. The details of this contrivance are so obvious, and
the principle on which it is founded so well understood, that
there was only one question which could render the result doubt-
ful ; and this was, — is there any diminution of effect by length-
ening the conducting wire 't It had been said that the electric
fluid from a common [tin-foil] electrical battery had been trans-
mitted through a wire four miles in length without any sensible
diminution of effect, and to every appearance instantaneously;
and if this should be found to be the case with the galvanic cir-
cuit, then no question could be entertained of the practicability
and utility of the suggestion above adverted to. I was therefore
induced to make the trial ; but I found such a sensible diminution
with only 200 feet of wire, as at once to convince me of the
impracticability of the scheme. It led me however to an inquiry
as to the cause of this diminution, and the laws by which it is
governed."*

Henry in his researches just referred to, (assisted by his friend
Dr. Ten-Eyck,) employed a small electro-magnet of one quarter
inch iron "wound with about 8 feet of copper wire." Excited
with a single pair " composed of a piece of zinc plate 4 inches
by 1, surrounded with copper," (about 56 square inches of zinc
surface,) the magnet sustained four pounds and a half. With
about 500 feet of insulated copper wire (.045 of an inch in
diameter) interposed between the battery and the magnet, its
lifting power was reduced to two ounces ; — or about 36 times.
With double this length of wire, or a little over 1000 feet, inter-
posed, the lifting power of the magnet was only half an ounce :
thus fully confirming the results obtained by Barlow. With a
small galvanic pair 2 inches square, acting through the same
length of wire (over 1000 fee:,) "the magnetism was scarcely
observable in the horse-shoe." Employing next a trough battery
of 25 pairs, having the same zinc surface as previously, the
magnet in direct connection, (which before had supported four
and a half pounds,) now lifted but seven ounces; — not quite half
a pound. But with the 1060 feet of copper wire (a little more

* "On the Laws of Electro-magnetic Action." Edinburgh Philosoph.
Jour. Jan. 1825, vol. xii. pp. 105-113. In explanation and justification
of this discouraging judgment from so high an authority in magnetics, it
must be remembered that both in the galvanometer and in the electro-
magnet, the coil best calculated to produce large effects, was that of least
resistance ; which unfortunately was not that best adapted to a long cir-
cuit. On the other hand, the most efficient magnet or galvanometer was
not found to be improved in result by increasing the number of galvanic
elements. Barlow in his inquiry as to the "law of diminution" was led
(erroneously) to regard the resistance of the conducting wire as increasing
in the ratio of the square root of its length, (p. 111.)

19

246 BULLETIN OF THE

than one-fifth of a mile) suspended several times across the large
room of the Academy, and placed in the galvanic circuit, the
same magnet sustained eight ounces : that is to say, the current
from the galvanic trough produced greater magnetic effect after
traversing this length of wire, than it did without it.

Speculating on this remarkable, and at the time, paradoxical
result, Henry suggests in explanation, that " a current from a
trough possesses more 'projectile' force (to use Professor Hare's
expression,) and approximates somewhat in ' intensity ' to the
electricity from the common machine. May it not also be a fact
that the galvanic fluid in order to produce the greatest magnetic
effect should move with a smaller velocity, and that in passing
through one-fifth of a mile, its velocity is so retarded as to pro-
duce a greater magnetic action ? But be this as it may, the fact
that the magnetic action of a current from a trough is at least
not sensibly diminished by passing through a long wire, is
directly applicable to Mr. Barlow's project of forming an electro-
magnetic telegraph ; * and it is also of material consequence in
the construction of the galvanic coil From these experiments
it is evident that in forming the coil we may either use one very
long wire, or several shorter ones, as the circumstances may
require : in the first case, our galvanic combinations must consist
of a number of plates so as to give ' projectile' force ; in the
second, it must be formed of a single pair."f

Here for the first time is presented to science the "intensity "
coil, — a spool of a single fine wire closely wound again and again
upon itself, — with its singular capabilities — not of power, but
(what was never before suspected nor imagined) of subtile ex-
citation from a distant source. Here for the first time is estab-
lished the important principle, that there must be a proportion
between the aggregate internal resistance of the battery, and the
whole external resistance of the conjunctive wire or conducting
circuit ; that for a " quantity" magnet of multiple coils (or their
equivalent a large wire of corresponding weight) a " quantity"
battery of surface, or a single galvanic element is required ;
while for an "intensity" magnet of extended continuous fine coil,
an " intensity " battery of many small' pairs is requisite :J with
the further discovery that the electro-motive force of the latter
form enables a very long conductor to be employed without seu-

* Really Laplace's project; — not Barlow's.

I Silliiuairs Am. Jour. Sci. Jan. 1831, vol. xix. pp. 403, 404.

j " For circuits of small resistance, galvanometers of small resistance
must be used. For circuits of large resistance, galvanometers of large
resistance must also be used ; not that their resistance is any advantage,
but because we cannot have a galvanometer adapted to indicate very
small currents without having a very large number of turns in the coil,
and this involves necessarily a large resistance." Prof. F. Jenkin. Ehc-
tricity and Magnetism, 12mo. London, and N. Y. 1&73, chap. iv. sect. 8,
p. 89.

20

PHILOSOPHICAL SOCIETY OF WASHINGTON. 247

sible diminution of the effect.* Professor Moll, the foremost of
Europeans in the chase, and close upon the heels of Henry in one
portion of his researches, produced a powerful "quantity" mag-
net, but one hopelessly and radically incapacitated from any
such application.

These memorable consequences of careful and judicious ex-
periment, carried on in 1829, and 1830, formed truly a most
pregnant epoch in the history of the infant science ; and consti-
tuted a valuable addition to the world's capital. Their adoption
underlies all subsequent applications of the intermittent magnet,
and is the indispensable basis of every form of the electro-mag-
netic telegraph since invented. They settled satisfactorily (in
Barlow's phrase) — the "only question which could render the
result doubtful :" and though derived from the magnet, were
obviously as applicable to the galvanometer needle.

It is idle to say in disparagement of these successes, that in
the competitive race of numerous distinguished investigators in
the field, diligently seaix-hing into the conditions of the newfound
agency, the same results would soon have been reached by others.
For of what discovery or invention may not the same be said ?
Only those who have sought in the twilight of uncertainty, can
appreciate the vast economy of effort, by prompt directions to
the path from one who has gained an advance. Not for what
might be, but for the actual bestowal, does he who first grasps a
useful truth, merit the return of at least a grateful recognition.

If these results apparently so simple when announced by
Henry, have never been justly appreciated either at home or
abroad, no such complaint ever escaped their author. No such
thought seems ever to have occurred to his artless nature. For
him the one sufficient incentive and recompense was the advance-
ment of himself and others in the knowledge of nature's laws.
With the telegraph consciously within his grasp, he was well
content to leave to others the glory and the emoluments of its
realization.

In the year 1831, Henry had suspended around the walls of
one of the upper rooms in. the Albany Academy, a mile of copper
bell-wire interposed in a circuit between a small Cruickshaiik
battery and an " intensity" magnet of continuous fine coil. A
narrow steel rod — a permanent magnet — pivoted to swing hori-
zontally like the compass needle, was arranged so that normally
when pointing north, this end remained in contact with one leg
of the soft iron core, while near the opposite end of the compass
needle, a small stationary office-bell was placed. At each exci-

* Beyond a certain maximnm length, there is of course a decrease of
power proportioned to tlie increased resistance of a lonj conductor: l>nt
the magnetizing effect has not been found to be diminished in the ratio
of its length.

21

248 BULLETIN OP THE

tation of the electro-magnet, the compass needle v/as repelled
from one leg (by its similar magnetism) and attracted by the
other leg, so that its free end tapped the bell. This simple
device the Professor was accustomed to exhibit to his classes, in
illustration of the facility of transmitting signals to a distance by
the swift action of electro-magnetism.

Henry regarded his "quantity" magnet as h^mg scientifically
more important than his "intensity" magnet; and his success in
constructing such, of almost incredible power, caused numerous
requisitions on his skill. In April, 1831, Professor Silliman pub-
lished in his Journal "An Account of a large Electro-Magnet
made for the Laboratory of Yale College," under his charge.
The iron horse-shoe about one foot high was made from a three
inch octagonal bar 30 inches long ; and was wrapped with 26
strands of copper wire each about 28 feet long. When duly
excited by a single galvanic element consisting of concentric
cylinders of copper and zinc, presenting about five square feet of
active surface, the magnet lifted more than a ton weight. For
reversing the polarity of the magnet, a duplicate battery was
oppositely connected with extensions of the ends of the coils, so
that either battery could be alternately dipped. With a load of
56 pounds suspended from the armature, the poles of the magnet
could be so rapidly reversed, that the weight would not fall.
Professor Silliman remarks of the maker: " He has the honor of
having constructed by far the most powerful magnets that have
been known ; and his last, weighing (armature and all) but S2|-
pounds, sustains over a ton ; — which is eight times more powerful
than any magnet hitherto known in Europe."* And Sturgeon
(the true foster-father of the magnet) thus heralds the Yale Col-
lege triumph : " By dividing about 800 feet of conducting wire
into 26 strands and forming it into as many separate coils around
a bar of soft iron about 60 pounds in weight and properly bent
into a horse-shoe form, Professor Henry has been enabled to pro-
duce a magnetic force which completely eclipses every other in
the whole annals of magnetism ; and no parallel is to be found
since the miraculous suspension of the celebrated oriental im-
poster in his iron coffin, "f

J7?(? first Electro-magnetic Engine. — Among his ingenious
applications of the new power, Henry's invention of the Elec-
tro-magnetic Engine should here be noticed. In a letter to

* Sillirhan's Am. Jour. Sci. April, 1831, vol. xx. p. 201. Relatively,
some of Henry's smaller magnets were many times more powerful than
this. A miniature one made by Dr. Ten-Eyck under his direction, sus-
tained 200 times its own weight ; and one still smaller, sustained more
than 400 times its own weight! (Sill. Am. Jour. Sci. vol. xix. p. 407.)

t Philosoph. Magazine; and Annah, 1832, vol. xi. p. 199.

22

PHILOSOPHICAL SOCIETY OF WASHINGTON, 249

his friend Professor Silliman, he says: " I have lately succeeded
in producing motion in a little machine, by a power which I
believe has never before been applied in mechanics, — by mag-
netic attraction and repulsion." The device consisted of a
horizontal soft iron bar, about seven inches long, pivoted at
its middle to oscillate vertically, and closely wrapped with three
strands of insulated copper wire, whose ends were made by
suitable extensions to project and bend downward at either
end of the beam in reversed pairs, so as conveniently to dip
into mercury thimbles in connection with the plates of the
battery. Two upright permanent magnets having the same
polarity, were secured immediately under the two ends of the
oscillating bar, but separated from them by about an inch. So
soon as the circuit was completed by the depression of one end
of the oscillating electro-magnetic bar, a repulsion at this end
co-operating with an attraction at the opposite end, caused im-
mediately a contrary dip of the bar, which by reversing the
polarity of this magnetic beam, thus produced a constant recip-
rocating action and movement. The engine beam oscillated at
the rate of 15 vibrations per minute for more than an hour, or
as long as the batteiy current was maintained.* This simple
but original device comprised the first automatic pole-changer or
commutator ever applied to the galvanic battery, — an essential
element not merely in every variety of the electro-magnetic
machine, but in every variety of the magneto-electric apparatus,
and in every variety of the highly useful induction apparatus.

In an interesting " Historical Sketch of the rise and progress
of Electro-magnetic Engines for propelling machinery," by the
distinguished philosopher James P. Joule, he remarks: "Mr.
Sturgeon's discovery of magnetizing bars of soft iron to a con-
siderable power, and rapidly changing their polarity by miniature
voltaic batteries, and the subsequent improved plan by Professor
Henry of 7-aising the magnetic action of soft iron, — developed
new and inexhaustible sources of force which appeared easily and
extensively available as a mechanical agent ; and it is to the in-
genious American philosopher above named, that we are in-
debted for the first form of a working model of an engine upon
the principle of reciprocating polarity of soft iron by electro-
dynamic agency "f

In Henry's deliberate contemplation of his own achievement,
his remarkable sagacity and sobriety of judgment were con-
spicuously displayed. Unperturbed by the enthusiasm so natu-

* Silliman's Am. Jour. Sci. July, 1831, vol. xx. pp. 340-343.

t Sturgeon's Atinals of Electricity etc., March, 1839, vol. iii. p. 430.
Sturgeon himself the first to devise a rotary electro-magnetic engine,
deserves honorable mention for correcting the statement of an American
writer, and declining his mistaken award by frankly recognizing Henry's
right to priority. (Atmals of Electricity, April, 1^39, vol. iii. p. 554 )

23

250 BULLETIN OF THE

ral to the successful inventor, he carefully scanned the capabilities
of this new dynamic agent. Considering the source of the
power, he arrived at the conclusion that the deoxidation of metal
necessary for the battery, would require the expenditure of at
least as much power as its combustion in the battery could re-
fund ; and that the coal consumed in such deoxidation could be
much more economically employed directly in the work to be
done.* As the battery consumption moreover was found to in-
crease more rapidly than the magnetic power produced, he M-as
at once convinced that it could never supersede or compete with
steam. t He believed however that the engine had a useful
future ill many minor applications where economy was not the
most important consideration.

When sometime afterward, a friend urged him to secure
patents on his inventions, — the " intensity" electro-magnet with
its combinations, and the magnetic engine with its automatic
pole-changer, earnestly assuring him that either one with proper
management would secure an ample fortune to its owner, he
firmly resisted every importunity ; declaring that he would feel
humiliated by any attempt at monopolizing the fruits of science,
which he thought belonged to the world. And this aversion to
self-aggrandizement by researches undertaken for truth, was
carried with him through life. J

While such disinterestedness cannot fail to excite our admira-
tion, it may perhaps be questioned whether in these cases it did
not from a practical point of view, amount to an over-fastidious-
ness : — whether such legal establishment of ownership, shielding
the possessor from the occasional depreciations of the envious,

* These consirleratioTis liavelieen mors than justified by later compara-
tive iiivestigat ons. Raukiiie estimates that the coiii-umptioii of cue pound
of zinc will not produce more tiian one-tenth the energy that one pound
of coal will ; and that though in the efficient utilization of this energy it
is four times superior, its useful work is therefore less than lialf that of
ooal ; while its cost is from forty to fifty times greater. ( The Steam Engine
and other Prime Movers. By W. J. M. Eankine, London and Glasgow,
1&59, part iv. art. 395, p. 541.)

t James P. .Joule i himself an inventor of an electro-magnetic engine)
in a letter dated May 28, 1839, said : '^ I can scarcely doubt that electro.-
magnetism will eventually be sub<tituted for steam in piopelling ma-
chinery." (Sturgeon's Annnis of Electricity, vol. iv. p. ]35.) This was
some years before he commenced his investigations on the mechanical
equivalent of heat and other motors. He subsequently estimated that
the consumption of a graiu of zinc though forty times more costly than
a grain of coal, produces only about one-eighth of the same mechanical
effect.

t This trait calls to mind Faraday's avowal made nearly thirty years
later, when in a letter to Messrs. Smith and Bentley dated January 3,
1859, (declining the publication of his " Juvenile Lectures") he said : " In
fact I have always loved science more than money ; and because mv occu-
pation is almost entirely personal, I cannot alford to get rich." (iieuce
Jones' Life of Faraday, vol. ii. p. 423.)

24

PHILOSOPHICAL SOCIETY OF WASHINGTON. 251

and securing by its more tangible remunerations tlie leisure and
the means for more extended researches, would not have been to
science more than a compensation for the supposed sacrifice of
dignity by the philosopher.*

Nor did this repugnance to patenting arise (as it sometimes
does) from any theoretical disapproval of the system. On the
contrary, he frequently expressed his strong conviction that a
judicious code of patent laws — if faithfully administered — fur-
nishes the most equitable method of recompensing meritorious
inventors. The institution was a good one — for others.

'The discovert/ of Magneto-electricity . — From the magnetizing
influence of the galvanic current, physicists were almost inevi-
tably led to expect the converse reaction; and this anticipation
appears to have been coeval with electro-magnetism. As early
as 1820, the illustrious Augustin Fresnel remarked : " It is natu-
ral to try whether a magnetic bar will not produce a galvainc
current in a helical wire surrounding it ;" and he made various
experiments to determine a question which was supposed to
involve the soundness of Ampere's theory. In November 1820,
he announced that though he at first supposed his attempt at the
magneto-electric decomposition of water was partially successful,
he was finally satisfied that no decisive result was obtained."}"

Five years later, Faraday attempted the same experimental
inquiry ; and among his earliest publications gave an account of
his unsuccessful trials. After describing his arrangements he
says : " The magnet was then put in various positions and to
different extents into the helix, and the needle of the galvanometer
noticed : no effect however upon it could be observed. The cir-
cuit was made very long, very short, of wires of different metals
and different diameters, down to extreme fineness, but the results
were always the same. Magnets more and less powerful were
used. . . . Hence it appears that however powerful the
action of an electric current may be upon a magnet, the latter
has no tendency by re-action to diminish or increase the intensity
of the former."!

Nor were American physicists discouraged by the records of
repeated failures : and when the great Henry magnet was re-
ceived at Yale College, Professor C. IT. Shepard (Chemical
Assistant to Professor Silliraan) at once attacked the problem
with this new equipment. He remarks: "As its magnetic flow

* Several hundred patents have since been granted in this country for
ingenious uiodifioations of — or inipiovements upon the electro-magnetic
telegraph ; and probably a liundred for equally ingenious varieties of the
electro-magnetic engine ; all of which would have been tributary to
Henry as an original patentee.

f Annates de C/iimIe et cle Physique, 1820, vol. xv. pp. 219-222.

j Quarterly Journal of Science, July 1825, vol. xix. p. 338.

25

252 BULLETIN OP THE

was SO powerful, I had strong hopes of being able to accomplish
the decomposition of water by its means. My experiment how-
ever proved unsuccessful. ... I hope however to resume
the research hereafter, under more favorable circumstances."*

Henry, unsatisfied with past efforts, determined to pursue the
subject in an exhaustive series of experiments ; and had reached
some momentary indications of the galvanometer, when his ex-
periments were temporarily interrupted. Meanwhile it was an-
nounced in May, 1832, that Faraday had secured the long sought
prize ; though the announcement was brief, and to those eager
for particulars, somewhat disappointing. Henry was accord-
ingly induced to publish in the following number of Silliman's
Journal (that for July) a sketch of his own trials both before
and after the announced discovery. With reference to Faraday's
discovery he remarks : " No detail is given of the experiments,
and it is somewhat surprising that results so interesting, and
which certainly form a new era in the history of electricity and
magnetism, should not have been more fully described before this
time in some of the English publications. The only mention I
have found of them is the following short account from the Annals
of Philosophy for April, under the head of Proceedings of the
Royal Institution. — 'Feb. 17. Mr. Faraday gave an account of
the first two parts of his researches in electricity ; namely volta-
electric induction, and magneto-electric induction. . . . If a
wire connected at both extremities with a galvanometer, be coiled
in the form of a helix around a magnet, no current of electricity
takes place in it. This is an experiment which has been made
by various persons hundreds of times, in the hope of evolving
electricity from magnetism. But if the magnet be withdrawn
from or introduced into such a helix, a current of electricity is
produced while the magnet is in motion, and is rendered evident
by the deflection of the galvanometer. If a single wire be
passed by a magnetic pole, a current of electricity is induced
through it which can be rendered sensible. 'f

"Before having any knowledge of the method given in the
above account, I had succeeded in producing electrical effects in
the following manner, which differs from that employed by Mr.
Faraday, and which appears to me to develop some new and
interesting facts. A piece of copper wire about thirty feet long
and covered with elastic varnish, was closely coiled around the

* Silliman's Am. Jour. Sci. April, 1831, vol. xx. p. 201, foot-note.

t Philosoph. Mag. and Annals of Phil. April, 1S32, vol. xi. pp. 300,
301. Although Faraday's first communication on galvanic iniluction,
and on magneto-electricity, was read before the Royal Society November
24, 1831, tlie published Transactions for 1832, containing this memoir
did not reach this country till more than a year later : so that the meager
abstract of the Royal Institution Proceedings above given, was the only
notice of this important discovery, — here accessible for many months.

26

PHILOSOPHICAL SOCIETY OF WASHINGTON. 253

middle of the soft iron armature of the galvanic magnet described
in vol. xix. of the American Journal of Science, and which when
excited will readily sustain between six hundred and seven
hundred pounds. The wire was wound upon itself so as to
occupy only about one inch of the length of the armature, which
is seven inches in all. The armature thus furnished with the
wire, was placed in its proper position across the ends of the
galvanic magnet, and there fastened so that no motion could take
place. The two projecting ends of the helix were dipped into
two cups of mercury, and these connected with a distant galvano-
meter by means of two copper wires each about forty feet long.
This arrangement being completed, I stationed myself near the
galvanometer and directed an assistant at a given word to im-
merse suddenly in a vessel of dilute acid, the galvanic battery
attached to the magnet. At the instant of immersion the north
end of the needle was deflected 30° to the west, indicating a
current of electricity from the helix surrounding the armature.
The effect however, appeared only as a single impulse, for the
needle after a few oscillations resumed its former undisturbed
position in the magnetic meridian, although the galvanic action
of the battery, and consequently the magnetic power still con-
tinued. I was however much surprised to see the needle sud-
denly deflected from a state of rest to about 20° to the east, or
in a contrary direction, when the battery was withdrawn from
the acid, and again deflected to the west when it was re-immersed.
This operation was repeated many times in succession, and uni-
formly with the same result, the armature the whole time remain-
ing immovably attached to the poles of the magnet, no motion
being required to produce the efi"ect, as it appeared to take place
only in consequence of the instantaneous development of the
magnetic action in one and the sudden cessation of it in the
other. . . . From the foregoing facts it appears that a cur-
rent of electricity is produced for an instant in a helix of copper
wire snrrounding a piece of soft iron whenever magnetism is
induced in the iron ; and a current in an opposite direction when
the magnetic action ceases; also that an instantaneous current
in one or the other direction accompanies every change in the
magnetic intensity of the iron.

"Since reading the account before given of Mr. Faraday's
method of producing electrical currents, I have attempted to
combine the effects of motion and induction." No increase of
effect was however observable. On comparing the two methods
separately, it was found that while the sudden introduction of
the end of a magnetized bar within the helix connected with the
galvanometer deflected the needle seven degrees, the sudden
magnetization of the bar when within the helix, deflected the
needle thirty degrees. A cylindrical iron bar was made to

' 27

254 BULLETIN OF THE

rotate rapidly on its axis within a stationary helix, by means of
a turning lathe, but no result followed.

In the following month (June) by employing a horse-shoe
armature (admitting longer coils), Henry succeeded in obtaining
vivid sparks from the magnet. "The poles of the magnet were
connected by a single rod of iron bent into the form of a horse-
shoe, and its extremities filed perfectly flat so as to come in per-
fect contact with the faces of the poles: around the middle of
the arch of this horse-shoe, two strands of copper wire were
tightly coiled one over the other. A current from one of these
helices deflected the needle one hundred degrees, and when both
were used, the needle was deflected with such force as to make
a complete circuit. But the most surprising effect was produced
when instead of passing the current through the long wires to
the galvanometer, the opposite ends of the helices were held
nearly in contact with each other, and the magnet suddenly ex-
cited : in this case a small but vivid spark was seen to pass be-
tween the ends of the wires, and this effect was repeated as often
as the state of intensity of the magnet was changed. ... It
appears from the May number of the Annals of Philosophy, that
I have been anticipated in this experiment of drawing sparks
from the magnet by Mr. James D. Forbes of Edinburgh who
obtained a spark on the 30th of March:* my experiments being
made during the last two weeks of June. A simple notification
of his result is given, without any account of the experiment,
which is reserved for a communication to the Royal Society of
Edinburgh. My result is therefore entirely independent of his,
and was undoubtedly obtained by a different process."

Henry's gratification at the acquisition of the new insight into
natural law, quite absorbed all sentiment of personal pride in its
independent attainment; and his appreciation and congratula-
tion of Faraday as the first discoverer of magneto-electricit}',
were hearty and unreserved. He was also particular always to
assign to Faraday the first observation of the curious phenomena
of momentary galvanic induction; although himself an inde-
pendent discoverer of the fact.

In the course of these experiments he made a very important
original observation on a peculiar case of self-induction, whereby
he was enabled to convert a galvanic current of "quantity" into
one of " intensity." This entirely new result seemed to contra-
dict all previous experience. He thus concludes his paper: "I
may however mention one fact which I have not seen noticed in
any work, and which appears to me to belong to the same class
of phenomena as those above described. It is this: — when a
small battery is moderately excited by diluted acid and its poles

* Philosoph. Mag. and Annals, May, 1832, vol. xi. pp. 359, 360.

28

PHILOSOPHICAL SOCIETY OF WASHINGTON. 255

(which should be terminated by cups of mercury) are connected
by a copper wire not more tlian a foot in length, no spark is per-
ceived wlien the connection is either formed or broken : but if a
wire thirty or forty feet long be used (instead of the short wire),
though no spark will be perceptible when the connection is made,
yet when it is broken by drawing one end of the wire from its
cup of mercury, a vivid spark is produced. . . . The effect
appears somewhat increased by coiling the wire into a helix: it
seems also to depend in some measure on the length and thick-
ness of the wire. I can account for these phenomena only by
supposing the long wire to become charged with electricity which
by its reaction on itself projects a spark wlien the connection is
broken."* This is the earliest notice of the curious phenomenon
of self-induction in an electric discharge.

Election as Professor at PiHnceton. — The Trustees of the
College of New Jersey at Princeton, were about this time in
search of a Professor to fill the chair of Natural Philosophy in
that College, made vacant by the resignation of Professor Henry
Vethake, wiio had accepted a Professorship of Natural Philosophy
in the recently established University of the City of New York.
Professor Henry had already won considerable I'eputation as a
lecturer and teacher, no less than as an experimental physicist.
Professor Silliman of Yale College, urging his appointment,
wrote : " Henry has no superior among the scientific men of the
country." And Professor Renvvick of Columbia College (New
York) still more emphatically added : "He has no equal."

Professor Henry was unanimously elected by the Trustees ;f
and he accepted the appointment : although strongly attached to
his first Academy, endeared to him by early memories, by six
years of successful labors, and by the warm regard of all his
associates. May it not be added that his residence at the capital
of the State of New York, was further endeared to him by life's
romance, — a most congenial and happy marriage contracted in
1830.

ELECTRICAL RESEARCHES AT PRINCETON : FROM 1833 TO 1842.

In November 1832, Henry left the scene of his early scientific
triumphs, the Albany Academy, and removed to Princeton with
his family. For a year or two he gave his whole attention and

* Silliman's Am. Jour. Sci., July, 1832, vol. xxii. p. 408.

f Dr. Maclean connected with the Faculty of the College of New .Jersey
at Piiuceton for fifty years, and for fourteen years its venerable president,
in his History of tlie College (2 vols. 8vo. Philadelphia, 1877,) gives a
Very interesting account of the appointment and election of Joseph Henry
as Professor of Natural Philosophy in 1832, vol. ii. pp. 288-291.

29

256 BULLETIN OF THE

exertions to the duties of exposition and instruction; and during
Dr. Torrey's visit to Europe in 1833, at the Doctor's request
Professor Henry filled ad interim his chair of Chemistry, Miner-
alogy, and Geology. These occupations left him no leisure for
the pursuit of original research. He subsequently gave lectures
on Astronomy, and also on Architecture.

In 1834, Henry constructed for the Laboratory of his College
an original form of Galvanic Battery; so arranged as to bring
into action any desired number of elements, from a single pair to
eighty-eight. Each zinc plate 9 inches wide and 12 inches
deep was surrounded by a copper case open at top and bottom,
and giving thus one and a half square feet of efficient surface.
Eleven of these in eleven separate cells, formed a sub-battery;
and eight of these were grouped together by means of adjustable
conductors, so as to form from the whole a single battery. By
means of a crank and windlass shaft in proper connection, any
one or more of the eight sub-batteries could be immersed or dis-
engaged, and if desired, a single cell could alone be charged. By
another arrangement of adjustable conductors, all the zinc plates
could be directly connected together, and all the copper plates
together, after the plan of Dr. Hare's " calorimotor" battery ;
thus giving the "quantity" effect due to a single element of 132
square feet of zinc surface, or of any smaller area desired. As
the author remarks concerning its various arrangements, "they
have been adopted in most cases after several experiments and
much personal labor." A detailed account of this battery was
given in a communication read January 16th 1835, before the
American Philosophical Society (of which he had recently been
elected a member), and was published in its Transactions.*

Meanwhile he had been engaged in his brief intervals of relaxa-
tion from his exacting professional cares during the past year, in
repeating and extending his interesting observations (commenced
at Albany in 1832), on the remarkable intensifying inJiuence of a
long conductor, and especially of a spiral one, when interposed
in a galvanic circuit of a single pair, or a battery of low " inten-
sity." A verbal communication on this curious form of "induc-
tion," was made to the Society on the same occasion as the
description of his battery, and was illustrated by experiments
exhibited before the Society.

Faraday in his "eighth series of Researches" (read before the
Royal Society June 5th 1834), pointed out very fully the differ-
ing actions of a single galvanic element giving a "quantity" cur-
rent, and of a series of elements giving an "intensity" current :f
thus entirely confirming the results obtained by Henry more than
three years previously.

* Trans. Am. Philox. Soc. vol. V. new series, art. iv. pp. 217-222.
t J'hil. Trans. Royal Soc. June 5, 1834, vol. cxxiv. art. 990-994, pp.
445, 446. Experimental Researches in Electricity, vol. i. pp. 301, 302.

30

PHILOSOPHICAL SOCIETY OF WASHINGTON. 257

In the Philosophical Magazine for November, 1834, appeared
a paper by Faraday, "On a peculiar condition of electric and
magneto-electric Induction:" in which he notices as a remark-
able fact, that while a short circuit wire from a single galvanic
element, gives little or no visible spark, a long conductor gives a
very sensible spark. "It is however very interesting thus to
observe an original current of electricity having a very low in-
tensity producing ultimately a counter current having an intensity
probably a hundred fold greater than its own, and the experi-
ment constitutes one of the very few modes we have at command
of converting quantity into intensity as respects electricity in cur-
rents." And he remarks: "If the connecting wire be much
lengthened, then the spark is much increased."*

In this interesting research, Faraday appears to have entirely
overlooked Henry's earlier labors in the same field ; — as contrary
to his usual custom, he makes no allusion to the same results
having been obtained, and i)ublished in Silliman's Journal two
years and a half before. f These observations were made by
Faraday the subject of his "ninth series of Researches," in a
communication " On the influence by induction of an electric cur-
rent on itself:" read before the Royal Society January 29th
1835. In this paper he repeats, that with a single galvanic pair,
a short wire will not give a shock; while the wire surrounding
an electro-magnet will give a shock at each breaking of the cir-
cuit. He found a similar result with the wire helix alone, — with-
out its magnetic core. "The power of producing these phe-
nomena exists therefore in the simple helix, as well as in the elec-
tro-magnet, although by no means in the same high degree." With
continuous straight wire of the same length, he obtained a similar
effect, — "yet not so bright as that from the helix." When a short
wire is used, "all these effects disappear;" although there is un-
doubtedly a greater "quantity" of electric current in the shorter
wire; thus giving "the strange result of a diminished spark and
shock from the strong current, and increased effects from the
weak one. "I

While Henry derived only satisfaction from these extended
verifications of his own observations, by one whom he had ac-
customed himself to look up to with admiration and regard Dr
A Dallas Bache his attached friend, then Professor of Natural
Philosophy m the Umversity of Pennsylvania,_more jealous
than himself of his scientific fame, stronglv urged and insisted
that he should immediately publish an account of his later re-
searches. Henry accordingly sent to the American Philosophical

* Philosoph. Mag. Nov. 1834, vol. v. pp. .351, 3.52.

t d!'"; ^^'' '^"'"'"" '^^'" •^"'^' ^^^^' '^"'- ^^''- P- 408, above quoted.
, Jo • ^""*" ■^''•^"' '^'"^- •^^"- 2^^' 1^35' ^"^- pxxv. art. 1061-10(17. and
lU7d, pp. 43-45. Experimental Re^enrches in Eleclricitit, vol. i. pp. 325-328.
Ihis memoir did not reach this country of course till a year later.
VOL. IL — IT 31

258 BULLETIN OF THE

Society a memoir (comprising the details of his recent verbal
communication) "On the lufiueuce of a Spiral Conductor in in-
creasing the Intensity of Electricity from a galvanic arrangement
of a Single pair, etc.," which was read before the Society, Feb-
ruary 6th, 1835.

After citing his former paper of July, 1832, the writer remarks
that he had been able during the past year to extend liis experi-
ments on the curious phenomenon. " These though not so
complete as I could wish, are now presented to the Society with
the belief that they will be interesting at this time on account of
the recent publication of Mr. Faraday on the same subject." He
then relates that employing a single pair of his battery (com-
prising one and a half square feet of zinc surface), he found as
in his earlier experiment in 1832, that the poles being cunnected
by a piece of copper bell-wire five inches long, no spark was
given on making or breaking contact. Fifteen feet of interposed
wire gave a very feeble spark ; and with successive additions of
fifteen feet, the effect increased until with 120 feet the maximum
spark appeared to be reached, and beyond this there was no
perceptible increase ; while with double this length (or 240 feet)
there seemed to be a diminution of intensity. From various
trials the inference was drawn that the length required for maxi-
mum effect varied with the size of the galvanic element. Tliicker
wires of the same length produced greater effect, depending in
some degree on the size of the battery. A wire of forty feet
when coiled into a cylindrical helix "gave a more intense spark
than the same wire uncoiled." A ribbon of sheet copper about
an inch wide and twenty-eight feet long, being covered with silk
and coiled into a flat spiral — like a watch spring — (after the plan
of Dr. Richie) gave a vivid spark wath a loud snap. When un-
coiled, it produced a much feebler spark. With the insulated
copper ribbon folded in its middle, and the double thickness
coiled into a flat spiral, there was no spark whatever, although
the same ribbon unrolled gave a feeble spark: thus showing that
the induction of the current upon itself was neutralized by flow-
ing equally in opposite directions in the double spiral. Witli a
larger copper ribbon one inch and a half wide, and 90 feet long,
spirally coiled (weighing 15 pounds) the snap of the spark could be
heard in an adjoining room with the door closed. Want of mate-
rial prevented the result being pushed further, so as to ascertain
the range of maximum effect with this form of conductor. With
increased battery surface, the effect was also increased ; so that
with eight elements of his battery arranged as a single pair (of
12 square feet) the spark on breaking contact " resembled the
discharge of a small Leyden jar highly charged." With the flat
spiral, no increase of effect was observable on the introduction
of a soft iron core into the axis of the spiral, forming a magnet.
With a helical or cylindrical coil about nine inches long, enclosing

32

PHILOSOPHICAL SOCIETY OP WASHINGTON. 259

an iron core, " the spark appeared a little more intense than
without the iron." The infei*ence is also drawn "from these ex-
periments, that some of the effects heretofore attributed to mag-
neto-electric action are chiefly due to the reaction on each other
uf the several spirals of the coil which surround the magnet."

In these researches it was found that when the two plates of
a single pair were placed even fourteen inches apart in an open
trough of diluted acid, " although the electrical intensity in this
case must have been very low, yet there was but little reduction
in the apparent intensity of the spark." It was also shown that
" the spiral conductor produces however, little or no increase of
effect when introduced into a galvanic circuit of considerable
intensity." When for example an "intensity" battery of two
Cruickshank's troughs, each containing 56 elements was employed
with the larger copper spiral, "no greater effect was perceived
than with a short thick wire :" in either case, only a feeble spark
being given.* An abstract of the results thus announced (and
which were obtained by Henry during the summer of 1834,) was
communicated by Dr. A. D. Bache, as a Secretary of the Ameri-
can Philosophical Society, to the Franklin Journal, in order to
give these interesting facts an earlier currency.f The date of
original discovery was however so well established, that this
friendly effort was scarcely necessary. |

Combined Circuits. — In 1835, or early in 1836, wires had been
extended across the front campus of the College grounds at
Princeton from the upper story of the library building to the
Philosophical Hall on the opposite side, through which signals
were occasionally sent, distinguished by the number of taps of
the electro-magnetic bell, first exhibited five years previously in
the hall of the Albany Academy. It has already been noticed,
that contrary to all the antecedent expectations of physicists,
Henry had established the fact that the most powerful form of
magnet (designated by hira the "quantity" magnet) is not the
form best adapted to distant action through an extended cir-
cuit. The ingenious idea occurred to him that notwithstand-
ing this fundamental fact, it would be quite easy to combine
the two systems so as to enable an operator to produce the most
energetic mechanical effects, at almost any required distance.

* Trans. Am. Phil. Soc. vol. v. n. fl. art. x. pp. 223-231.

+ Joimicil of the Franklin Institute, March, 1835, vol. xv. pp. 169, 170.

t M Becqnerel in his elaborate Treatise on Electricity, in the chapter
on " The influence of an electric current on itself by induction," says with
re'ra.rA to the increase of tension in a feeble current when passing through
along spiral conductor, " The effects observed in these circumstances
appear to have been noticed for the first time by Professor Henry.
( Traite experimental de VEIectricite et du Magnetisme, 8vo. 7 vols. Pans,
1824-1840, vol. v. art. 1261, p. 231.)

33

260 BULLETIN OF THE

It is simply necessary to employ with the distant "intensity"
magnet an" oscillating armature with a suitable prolongation
so arranged as to open and close the short circuit of an ad-
joining " quantity" magnet of any practicable power : — a work
which indeed could be accomplished by the mere swing of the
most delicate galvanometer needle. Professor Henry had con-
structed for his own laboratory a large electro-magnet designed
to surpass the celebrated magnet made foi j'ale College; and
with it he was enabled to exhibit to his class, by employing a
small portion of his " quantity" battery, an easy lifting power
of more than three thousand pounds.* Such was the mechanical
agency he called into action through his telegraphic circuit, by
simply lifting its galvanic wire from a mercury thimble, or by
again dipping it into the same. Although this special com-
bination has not found any important application, its principle
underlies all the various forms and uses of the " relay" magnet
and local battery since employed.

Visit to Europe. — In order to give Professor Henry a much-
needed rest from his diligent services and close application of
the past four years, the Trustees of his College liberally allowed
him a year's absence with full salary : thus affording him for
the first time a long coveted opportunity of visiting Europe.

In February of 1837, in company with his valued and faithful
friend, Professor Bachp, he arrived in England ; where the two
American physicists formed ready and lasting intimacies with
some of the most distinguished worthies of Great Britain.
Everywhere received with courteous and cordial consideration,
they both ever carried with them agreeable memories of their
holiday sojourn abroad.

In London, many pleasant interviews with Faraday, formed a
memorable circumstance. Wheatstone, then Professor of Ex-
perimental Philosophy in King's College, was engaged in de-
veloping his system of needle telegraph : and Henry had the
satisfaction of finding that his own early investigations were
recognized and appreciated, and their results successfully
adopted. "Wheatstone unfolded freely to his visitors his numerous
projects ; and particularly his arrangement of supplementary
local circuit from an additional battery, for sounding an electro-
magnetic signal, by being brought into action b}^ a movement
from the main line circuit.f Henry had then the pleasure of
detailing to him his own similar combination of two elcctro-

* It is said that this magnet has been made to sustain 3500 ponnrls.

t This was early in April, 1837. (Smithsonian Report for 1857, p. 111.)
Two months later, or .Tune 12ih, 1837, Wlieatstone in conjunction with W.
F. Cooke had secured a patent on his system of telegraph, including the
combination of circuits.

34

PIIILOSOPIITCAL SOCIETY OF AVASIIINOTON. 201

magnetic circuits, experimentally tried more than a year jire-
viously.

Nearly a year was employed in foreifi'ii travel, most jileasantly
and beneficially both for mind and body : tlio greater portion of
the time however being spent in Ijondon, in Paris, (where
Henry formed the acipiaintance of Arago, Jieecpierel, I)e la
Rive, Biot, Gay-Lussae, and other celebrities,) and in Kdiii-
burgh, where he also found a galaxy of eminent and congenial
minds.

In September of the same year (1837) ho attended the meet-
ing of the British Association at I^iverpool ; where being invited
to speak, he made a brief communication on some electrical
researches in regard to the phenomenon known as the " lateral
discharge:" — a study to which he had been led l)y some remarks
of Dr. Koget on the subject, "The result of the analysis was
in accordance with an opinion of Biot — that the lateral dis-
charge is due only to the escape of the small quantity of
redundant electricity which always exists on one side or the
other of ajar, and not the whole discharge." Hence we could
increase or diminish tin; lat(!ral action by any means which affect
the quantity of free electricity: — as by "an increas(! of the
thickness of the glass, or by substituting for the small knob of
the jar, a large ball. But the arrangement which produces the
greatest effect is that of a long fine copper wire insulated, —
parallel to the horizon, and terminated at each (aid by a small
ball. When sparks are thrown on this from a globe of about a
foot in diameter, the wire at each discharge beef)mes beautifully
luminous from one end to the other, even if it be a hundred feet
long : rays arc given off on all sides perpcndictdar to the axis of
the wire:" — forming a continuous electrical brush. It was also
stated "that the same (pianlity of electricity could be made to
remain on the wire, if grndually communicated [by a point] ; but
when thrown on in the form of a spark, it is dissipated as before
described :" — as though possessing a kind of moment um. When
two or more wires are arranged in jinrallel lines (in electrical
connection), only the outer sides of the exposed wires become
luminous: atul "when the wire is formed into n flat spiral, the
outer spiral alone exliibits the lafernl disehnrge, but the light in
this case is very brilliant : the inner s])irals appear to increase
the effect by induction." In like manner when a ball was
attached to the middle of a vertical lightning-rod having a good
earth-connection, " when spnrks of nbout an inch and a hnlf were
thrown on the ball, corresponding lateral sytarks could be drawn
not only from the parts of the rod between the ground and the
ball, but from the part above, even to the top of the rod." *

At the same meeting, before the section on Mechanics and

* Re/>nrt nf Brit. Association, for 1837, pp. 22-24, of Abstracts.

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262 BULLETIN OF THE

Engineering, Henry gave by request an account of the great
extension of the Railway and Canal systems in the United States :
which was listened to with great attention and interest. He also
referred to the inland or river navigation in our country,
describing the improvements introduced into our large river
steam-boats, especially on the Hudson river in New York State ;
where the usual speed was fifteen miles per hour or more.*

In November, 1837, Henry returned from bis foreign tour
greatly invigorated, — bringing with him some new apparatus :
and with increased zest he re-embarked upon the duties of his
professorship. Continuing his studies of electrical action, he
presented verbally to the American Philosophical Society, Feb-
ruary 16th 1838, a notice of further observations on the "lateral
discharge" of electricity while passing along a wire, going to
show that even with good earth connection, free electricity is not
conducted silently to the ground. f

In May, 1838, he announced to the Society the production of
currents by induction from ordinary or mechanical electricity,
analogous to that first obtained by Faraday from galvanism in
1831 : and the further curious fact that on the discharge from a
Leyden jar through a good conductor, a secondary shock from a
perfectly insulated near conductor could be obtained more intense
than the primary shock directly from the jar.|

These investigations having in view the discovery of " induc-
tive actions in common electricity analogous to those found in
galvanism" (commenced in the Spring of 1836), led to renewed
examination of the secondary galvanic current, which since No-
vember 24th, 1831, (or for seven years,) bad received no special
attention. Henry's very interesting series of experiments were
detailed in a somewhat elaborate memoir read before the Ameri-
can Philosophical Society, November 2nd, 1838. Employing
five different sized annular spools of fine wire (about one-fiftieth
of an inch thick) varying from one-fifth of a mile to nearly a
mile in length (which might be called " intensity " helices) ; and
six flat spiral coils of copper ribbon varying from three-quarters
of an inch to one inch and a half in width, and from 60 to 93
feet in length (which might be called "quantity" coils), he was
able to combine them in various ways both in connection and in
parallelism. A cylindrical battery of one and three quarters square

*Satrie Report, Abstract?, p. 135. It was on this occasion that Dr.
Lardner, generalizing probably from his observations on the Ihames,
ventured (not very conrteously) to doubt whether any such speed as fif-
teen miles per hour on water, could ordinarily be effected. (SilK Am
Jour. Sci. Jan. 1838, vol. xxxii. p. 296.) The same authority affirmed
the futility of attempting oceanic steam navigation.

t Proreerli>u/s Am. Phil. Soc. Feb. 16, 1838, vol. i. p. 6.

t Proceedings Am. Phil. Soc. May 4, 1838, vol. i. p. 14.

36

PHILOSOPHICAL SOCIETY OF WASHINGTON. 263

feet of zinc surface was principally used ; and the galvanic cir-
cuit was interrupted by drawing one end of the copper ribbon or
wire over a rasp in good metallic contact with the other pole of
the battery.

From the energetic action of the flat ribbon coil in producing
the induction of a current on itself, it was inferred that the sec-
ondary current would also be best induced by it. With the sin-
gle larger ribbon coil in connection with the battery, and another
ribbon coil placed over it resting on an interposed glass plate,
at every interruption of the primary circuit, an induction spark
was obtained at the rubbed ends of the second coil ; though the
shock was feeble. With a double wire spool (one within the
other) of 2650 yards, placed above the primary coil (having about
the same weight as the copper ribbon) the magnetizing effects
disappeared, the sparks were much smaller, " but the shock was
almost too intense to be received with impunity." The secondary
current in this case was one of small "quantity" but of great
"intensity." With a single break of circuit in the primary, it
was passed through a circle of 56 students of his senior class,
with the effect of a moderate charge from a Leyden jar. From
various experiments, the limit of efficient length for a given gal-
vanic power was ascertained ; beyond which the induced current
was diminished. Employing a Cruickshauk battery of 60 small
elements (4 inches square) he found with the ribbon coil that the
induced currents were exceedingly feeble, but with the long wire
helix as the primary circuit that strong indications were produced.
By the alternations of the ribbon and wire coils, the fact was
established "that an intensity current can induce one of quantity,
and by the preceding experiments the converse has also been
shown that a quantity current can induce one of intensity;" a
result which has had an important bearing on the subsequent
development of the electro-magnetic " Induction-Coil." With a
long ribbon coil receiving the galvanic current from 35 feet of
zinc surface, sensible induction shocks could be felt from a large
annular coil of four feet diameter (containing five miles of wire)
when placed in parallelism at a distance of four feet from the pri-
mary coil: while at the distance of one foot the shock became
too severe to be taken. With this arrangement an induction
shock was given from one apartment to another, through the
intervening partition.

Successive orders of Induction. — When it is considered that
the primary current in such eases has a considerable duration,
while the secondary current is but momentary, being developed
only at the instant of change in the primary, it could certainly
not have been expected that this single instantaneous electrical
impulse of reaction would be capable of acting as a primary
current, and of similarly inducing an action on a third independ-

37

264 BULLETIN OF THE

ent circuit : and during the seven years in which galvanic induc-
tion had been known, no physicist ever thought of making
the trial. Theoretically it might perhaps have been inferred,
if such tertiary induction had any existence, as it would be
coincident not with the instantaneous secondary induction, but
with the initiation and termination of such momentary current,
and hence in opposite signs — separated by an inappreciable
interval of time, that the whole phenomenon would probably be
entirely masked by a practical neutralization. The experiments
of Henry fully established, however, the new and remarkable
result of a very appreciable tertiary current. By connecting
the secondary coil with another at some distance from the pri-
mary so as not to be influenced by it directly, but forming
with the secondary a single closed circuit, not only was the
distant coil capable of producing in an insulated wire helix
placed over it, a distinct current of induction at the interruption
of the primary, but sensible shocks were obtained from it. The
experiment was pushed still further ; and inductive currents of
a fourth degree were obtained. " By a similar but more ex-
tended arrangement, shocks were received from currents of a
fourth, and a fifth order: and with a more powerful primary cur-
rent, and additional coils, a still greater number of successive
inductions might be obtained. ... It was found that with the
small battery a shock could be given from the current, of the
third order to twenty-five persons joining hands ; also shocks per-
ceptible in the arms were obtained from a current of the fifth
order." As Henry simply remarks : " The induction of currents
of different orders, of suSicient intensity to give shocks, could
scarcely have been anticipated from our previous knowledge of
the subject." By means of the small magnetizing helix intro-
duced into each circuit, the direction of these successive currents
was found to be alternating or reversed to each other.

The concluding section of this important memoir is occupied
with an account of " The production of induced currents of the
different orders from ordinary electricity." An open glass cylin-
der about six inches in diameter was provided with two long nar-
row strips of tin foil pasted around it in corresponding helical
courses, the one on the outside and the other on the inside,
directly opposite to each other. The inner coiled strip had its
extremities connected with insulated wires which formed a circuit
outside the cylinder, and included a small magnetizing helix.
The outer tin foil strip was also connected with wires so that an
electrical discharge from a half-gallon Leyden jar could be passed
through it. The magnetization of a small needle indicated an
induced current through the inner tin-foil ribbon corresponding
in direction with the outer current from the jar.* By means of

* About a year ]atpr, the Hiistineuisli^'d Gprman plt^otririan Pptpr Risss,
apparently unaware of Henry's resPHrihes, discovered the secondary cur-

38

PHILOSOPHICAL SOCIETY OF WASHINGTON. 265

a second glass cylinder similarly provided with helical tin-foil
ribbons in suitable connections a tertiary current of induction
was obtained, analogous to that derived from galvanism. " Also
by the addition in the same way of a third cylinder, a current of
the fourth order was developed."

Similar as these successive inductions from an electrical dis-
charge were to those previously observed in the case of the gal-
vanic current, they presented one puzzling diflerence in the direc-
tions of the currents of the diflureut orders. " These in the
experiments with the glass cylinders, instead of exhibiting the
alternations of the galvanic currents, were all in the same direc-
tion as the discharge from the jar, or in other words they were all
plus.'" On substituting for the tinned glass cylinders, well insu-
lated copper coils, " alternations were found the same as in the
case of galvanism." The only difference apparently between the
two arrangements, was that the tin-foil ribbons were separated
only by the thin glass of the cylinders, while the copper spiral
coils were placed an inch and a half apart. By varied experi.
meuts, the direction of the induced currents was found to depend
notably on the distance between the conductors ; — the induction
ceasing at a certain distance, (according to the amount of the
charge and the characters of the conductors,) and the direction
of the induced current beyond this critical distance being contrary
to that of the primary current.* "With a battery of eight half-
gallon jars, and parallel wires about ten feet long, the change in
the direction did not take place at a less distance than from
twelve to fifteen inches, and with a still larger battery and '.onger
conductors, no change was found although the induction was
produced at the distance of several feet." With Dr. Hare's bat-
tery of 32 gallon jars, and a copper wire about one-tenth of an
inch thick and 80 feet long stretched across the lecture-room and
back on either side toward the battery, a second wire stretched

rent induced from mechanical electricity, by a very siniilar experiment.
iPoggendorfif's Aiinalen der Physik unci Cliemle, 1«39, No. 5, vol. xlvii. pp.
55-7(3.)

* The variation in the direction of polarization (without reference to
induction current.s) appears to have been first noticed by F. Savary, some
dozen years before. In an important memoir communicated to the Paris
Academy of Sciences .luly 31, 1826, M. Savary announced that "llie
direction of the magnetic polarity of small needles exposed to an electric
current directed alons a wire stretched longitudinally, varies with the
distance of the wire :"— tlie action beinsr found to be periodical with the
distance. M. Savary observed tliree periods, and also the tact that the
distances of maximum effect and of the nodal zeros " vary with the length
and diameter of the wire, and with the intensity of the discharge." He
also found that " when a helix is used for magnetizing, the distance at
which the needle placed within it is from the conducting wire, is indif-
ferent; but the direction and the degree of magnetization depends on the
intensity of the discharge, and on the ratio between the length and size
of the wire." (Crewster's Edinburgh Jour. Sti. Oct. 1826, vol. v, p. 369. J

39

266 BULLETIN OF THE

parallel with the former for about 35 feet and extended to form
an independent circuit (its ends being connected with a small
magnetizing helix,) was tested at varjing distances beginning
with a few inches until they were twelve feet apart : p.t which dis-
tance of the parallel wire, its induction though enfeebled, still
indicated by its magnetizing power, a direction corresponding
with the primary current. The form of the room did not permit
a convenient separation of the two circuits to a greater dis-
tance.*

The eminent French electrician Becquerel, in a chapter on
Induction in his large work, remarks : " Quite recently M. Henry,
Professor of 2satural Philosophy in New Jersey, has extended
the domain of this branch of physics : the results obtained by
him are of such importance, particularly in regard to the intensity
of the effects produced, that it is proper to expound them here
with some detail." Twenty pages are then devoted to these
researches, f.

A memoir was read before the Society, June 19th, 1840, giving
an account of observations on the two forms of induction occur-
ring on the making and on the breaking of the primary galvanic
circuit, the two differing in character as well as in direction. In
these experiments he employed a Daniell's constant battery of 30
elements; the battery being "sometimes used as a single series
with all its elements placed consecutively, and at others in two
or thi'ee series, arranged collaterally, so as to vary the quantity
and intensity of the electricity as the occasion might require."
As the initial induction had always been found so feeble as to
be scarcely perceptible, (although in quantity sufficient to affect
the ordinary galvanometer as much as the terminal induction,)
most of the results previously obtained (such as the detection of
successive orders of currents) were derived from the strong in-
ductions at the moment of breaking the circuit. It became
therefore important to endeavor to intensify the initial induction
for its more especial examination : and this it was found could
be effected in two ways, — by increasing the "intensity" of the
battery, and by diminishing within certain limits the length of
the primary coil.

" With the current from one element, the shock at breaking
the circuit was quite severe, but at making the same it was very
feeble, and could be perceived in the fingers only or through the

* Trans. Am. Phil. Soc. vol. vi. tipw senVs, art. ix. pp. 303-337. In
the Proceediiig.s of the Society for Nnvemher 2(1, 1838, when this metnoir
was read, it is recorded " Profe.-<sor Hhih-.y made a verbal comnmnication
iluring the course of which h*^ illustrated experimentally the phenomena
developed in his paper." {Proceed. Am. Phil. Soc. Nov. 2, 1838, vol. i.

P-5-t)

t Traite experimental deVElectricite et du Magnetisme, vol. v. pp. 87-107.

40

PHILOSOPHICAL SOCIETY OP WASHINGTON. 2GT

tongue. With two elements in tlie circuit the shock at the
beginning was slightly increased : with three elements the in-
crease was more decided, while the shock at breaking the circuit
remained nearly of the same intensity as at first, or was compa-
ratively but little increased. When the number of elements was
increased to ten, the shock at making contact was found fully
equal to that at breaking, and by employing a still greater num-
ber, the former was decidedly greater than the latter, the difference
continually increasing until all the thirty elements were introduced
into the circuit. . . . Experiments were next made to deter-
mine the influence of a variation in the length of the coil, the
intensity of the battery remaining the same." For this purpose
the battery consisting of a single element " was employed ; and
the length of the copper ribbon coil was successively reduced
from 60 feet, by measures of 15 feet. With 45 feet, the initial
induction was stronger than with 60 feet : with the next shorter
length it was more perceptible, and increased in intensity with
each diminution of the coil, until a length of about fifteen feet
appeared to give a maximum result." At the same time it was
found that " the intensity of the shock at the ending of the bat-
tery current diminishes with each diminution of the length of
the coil. ... By the foregoing results we are evidently
furnished with two methods of increasing at pleasure the intensity
of the induction at the beginning of a battery current, the one
consisting in increasing the intensity of the source of the elec-
tricity, and the other in diminishing the resistance to conduction
of the circuit while its intensity remains the same."

Having thus succeeded in exalting the initial induction, Henry
proceeded in his investigation. Distinct currents of the third,
fourth, and fifth orders were readily obtained from it ; and as was
anticipated, with their signs (or directions) the reverse of the
corresponding orders derived from the terminal induction. In
other respects "the series of induced currents produced at the
beginning of the primary current appeared to possess all the
properties belonging to those of the induction at the ending of
the same current."

In the course of these investigations the idea having occurred
to him " that the intense shocks given by the electrical fish may
possibly be from a secondary current," as it appeared to him
that "this is the only way in which we can conceive of such
intense electricity being produced in organs imperfectly insulated
and immersed in a conducting medium," he endeavored to simu-
late the eflFect by arranging a secondary wire coil furnished with
terminal handles, over a primary copper ribbon coil, the two
being insulated as usual. "By immersing the apparatus in a
shallow vessel of water, the handles being placed at the two ex-
tremities of the diameter of the helix, and the hands plunged

41

268 BULLETIN OF THE

into the water parallel to a line joining the two poles, a shock is
felt through the arms."

The former experiment of obtaining an induction shock from
one room to another through a partition, was repeated on a
still larger scale. AH the coils of copper ribbon having been
united in a single continuous conductor of about 400 feet in
length, " this was rolled into a ring of five and a half feet in
diameter, and suspended vertically against the inside of the large
folding doors which separate the laboratory from the lecture-
room. On the other side of the doors in the lecture-room and
directly opposite the coil was placed a helix formed of upwards
of a mile of copper wire, one-sixteenth of an inch in thickness,
and wound into a hoop of four feet in diameter. With this
arrangement, and a battery of 147 square feet of zinc surface
divided into eight elements, shocks were perceptible in the tongue
when the two conductors were separated to the distance of nearly
seven feet. At the distance of between three and four feet, the
shocks were quite severe. The exhibition was rendered more
interesting by causing the induction to take place through a
number of persons standing in a row between the two con-
ductors."

The second section of the memoir is mainly occupied with
details of experiments on the screening effect of conducting plates
(of non-magnetic metals) when interposed between the primary and
secondary coils; showing remarkable contrasts in the "quantity"
and "intensity" classes of galvanic effects. When the annular
spool or helix (of nearly one mile of copper wire) was employed
with the large spiral coil of copper ribbon, " the coil being con-
nected with a battery of ten elements, the shocks both at making
and breaking the circuit were very severe ; and these as usual
were almost entirely neutralized by the interposition of the zinc
plate. But when the galvanometer was introduced into the
circuit instead of the body, its indications were the same whether
the plate was interposed or not : or in other words the galvano-
meter indicated no screening, while under the same circumstances
the shocks were neutralized. A similar effect was observed
when the galvanometer and the magnetizing helix were together
introduced into the circuit. The interposition of the plate en-
tirely neutralized the magnetizing power of the helix (in refer-
ence to tempered steel) while the deflections of the galvanometer
were unaffected." The induction currents of the third, fourth,
and fifth orders, were found to be of considerable " intensity;" —
magnetizing steel needles, giving shocks, not being interrupted
by a drop of water placed in the circuit between the ends of the
severed wire, — and yet being screened or neutralized Ijy a me-
tallic plate interposed between the coils.*

* Trans. Am. Phil. Sue. June 184^, vol. viii. u. s. art. i. pp. 1-18,

42

PHILOSOPHICAL SOCIETY OF WASHINGTON. 269

A continuation of the memoir was read before the Philoso-
phical Society November 20th, 1840, discussing further the
theoretical differences between an initial or an increasing gal-
vanic current, and a decreasing or a terminal current, in pro-
ducing the phenomena of induction. On the same occasion
Henry described " an apparatus for producing a reciprocating
motion by the repulsion in the consecutive parts of a conductor
through which a galvanic current is passing." About ten years
before, he had devised the first electro-magnetic engine (ope-
rating by intermittent magnetic attractions and repulsions); and
now he had contrived the first galvanic engine, operating by the
analogous intermittent attractions and repulsions of the electric
current.*

In June 1842, he presented a communication to the Society
recounting an investigation of some anomalies in ordinary elec-
trical induction. While with the larger needles ("No. 3 and No.
4") subjected to the magnetizing helix, the polarity was always
conformable to the direction of the discharge, he found that when
very fine needles were employed, an increase in the force of the
electricity produced changes of polarity. About a thousand
needles were magnetized in the testing helices in these researches.
This puzzling phenomenon was finally cleared up by the important
discovery that an electrical equilibrium was nut instantaneously
effected by the spark, but that it was attained only after several
oscillations of the flow. "The discharge, whatever may be its
nature is not correctly represented by the single transfer from
one side of the jar to the other : the phenomena require us to
admit the existence of a principal discharge in one direction, and
then several reflex actions backward and forward, each more
feeble than the preceding, until the equilibrium is obtained. "f
In every case therefore of the electrostatic discharge, the testing
needles were really subjected to an oscillating alternation of cur-
rents, and consequently to successive partial de-magnetizations
and re-magnetizations. The complications produced by this re-
sidual action, satisfactorily explained for the first time, the dis-
cordant resslts obtained by different investigators. This singular
reflux of current was ingeniously applied by Henry to explain the
apparent change of inductive current with differing distances.
Should the primitive discharge wave be in excess of the magnetic

* Proceedings Am. Phil. Soc. Nov. 20, 1840, vol. i. p. 301.

f Proceedings Am. Phil. Soc. .June 17, 1842, vol. ii. pp. 193. — Helniholtz
some five years later (iu 1847), but quite independently, suggested "a
backward and forward motion between the coatings" when the Leyden
jar is discharged. And still five years later (in 185li) Sir William Thom-
son made the same independent conjecture. To F. Savary however is
due the credit of liaving first thrown out the hypothesisof electrical oscil-
lations, as earl^ ao in 1827.

43

270 BULLETIN or THE

capacity of the needle at a giveu position, the return wave might
be just sufiQcient to completely reverse its polarity, and the
diminished succeeding wave insufficient to restore it to its former
condition; while at a greater distance, the primitive wave might
be so far reduced as to just magnetize the needle fully, and the
second wave, being still more enfeebled, would only partially de-
magnetize it, leaving still a portion of ihe original polarity ; and
so for the following diminished oscillations.

In the course of these extended researches the presence of in-
ductive action was traced to most surprising and unimagined
distances. "A single spark from the prime conductor of the
machine, of about an inch long, thrown on the end of a circuit of
wire in an upper room, produced an induction sufficiently power-
ful to magnetize needles in a parallel circuit of wire placed in the
cellar beneath, at a perpendicular distance of thirty feet, with
two floors aud ceilings — each fourteen inches thick intervening."

"The last part of the series of experiments relates to induced
currents from atmospheric electricity. By a very simple arrange-
ment, needles are strongly magnetized in the author's study, even
when the flash is at the distance of seven or eight miles, and
when the thunder is scarcely audible. On this principle he pro-
poses a simple self registering electrometer, connected with an
elevated exploring rod." For obtaining the results above alluded
to, a thick wire was soldered to the edge of the tin roof of his
dwelling and passed into his study through a hole in the window
frame ; while a similar wire passing out to the ground, terminated
in connection with a metal plate in a deep well close by. Between
the wire ends within his study, various apparatus, including mag-
netizing helices of different sizes and characters could be attached,
so as to be within the line of conduction from the roof to the
ground. The inductions from atmospheric discharges were found
to have the oscillatory character observed with the Leyden jar;
and by interposing several magnetizing helices wn'th few and with
many convolutions, he was able to get from a needle in the former
the polarity due to the direct current, and in the latter, that due
to the return current; thus catching the lightning (as it were)
upon the rebound.

In examining the "lateral discharge" from a lightning-rod in
good connection with the earth, he had often observed that while
a spark could be obtained sufficiently strong to be distinctly felt,
it scarcely affected in the slightest degree a delicate gold-leaf
electroscope. How explain so incongruous a phenomenon ?
Henry detected the very simple solution, by a reference to the
self-induction of the rod, — a negative wave passing followed im-
mediately by a positive wave so rapidly as to completely neutralize
the effect upon the electroscope before the inertia of the gold leaf
could be overcome, while actually producing a double sj^ark (sen-
sibly co-incident) to aud from the recipient.

44

PHILOSOPHICAL SOCIETY OF "WASHINGTON. 2T1

A few months later, "he had succeeded in magnetizing needles
by the secondary current, in a wire more than two hundred and
twenty feet distant from the wire through which the primary cur-
rent was passing, excited by a single spark from an electrical
machine."* In this case the primary wire was his telegraph
line stretched seven years before across the campus of the College
grounds in front of Nassau Hall : the secondary or induction wire
being suspended in a parallel direction across the grounds at the
rear of JSassau Hall, with its ends terminating in buried metallic
plates : — the large building intervening between the two wires.

This brilliant series of contributions to our knowledge of a most
recondite and mysterious agent, placed Henry, by the concurrent
judgment of all competent physicists, in the very front rank of
original investigators. His persevering researches in the elec-
trical paradoxes of induction, perhaps more than any similar ones,
tended to strengthen the hypothesis of an agtherial dynamic agency ;
although he himself had for a long time been inclined to favor the
material hypothesis. |

INVESTIGATIONS IN GENERAL PHYSICS: FROM 1830 TO 1846.

In order to give a proper connection to the experimental in-
quiries undertaken by Henry in various fields, it is necessary to
pause here, and to recur to some of bis earlier scientific labors.

Meteorology. — From an early date Henry took a deep interest
in the study of meteorology : not only on account of its practical
importance, but from its relation to cosmical physics, and because
from the very complexity and irregularity of its conditions, it
challenged further investigation and stood in need of larger gene-
ralizations. His early nssociation with Dr. T. Romeyn Beck in
the first development of the system of meteorological observations
established in the State of New York, has already been referred
to in the sketch of his "Early Career." This act«ve and zealous
co-operation continued from 1827 to J 832; or as long as he re-
sided in Albany.

In September of 1830, he commenced a series of observations
for Professor Renwick of Columbia College, to determine the
magnetic intensity at Albany. With the assistance of his
brother-in-law, Professor Stephen Alexander, these observations

* Proceedings Am. Phil. Sor. Oct. 21, 1842, vol. ii. p. 229.

f In a paper "On the Theory of the so-called Imponderables" published
some years later, in referring to the phenomena of electrical oscillation in
di.'Jcharge, and of the series of inductions taking place and "extending to
a surprising distance on all sides," he remarks: "As these are the results
of currents in alternate directions, they must produce in surrounding
space a series of plus and minus motions, analogous to — if not identical with
undulations." {Proceed. Amer. Association, Albany, Aug. 1851, p. 89.)

45

272 BULLETIN OF THE

were continued daily for two months.* In April, 1831, a second
series of observations was commenced ; in tiie course of wliit-h
his attention was attracted by a great disturbance of the needle
during the time of a conspicuous " aurora" on the 19th of April,
1831. At noon of the 19th the oscillations were found to be
perfectly. accordant with previous ones, but at 6 o'clock P. M. a
remarkable increase of magnetic intensity was indicated. At 10
o'clock of the same evening, during the most active manifestation
of the aurora, the oscillations of the needle were again examined.
" Instead of still indicating as at 6 o'clock an uncommonly high
degree of magnetic intensity, it now showed an intensity con-
siderably lower than usual." Thus, designating the normal
intensity at the place as unity, at 6 o'clock it had increased to
1.024, and at 10 o'clock had subsided to 0.993, which according
to Hansteen's observations is the usual relation of magnetic dis-
turbance by an aurora. f An account of these results was com-
municated by Henry to the Albany Institute, January 26, 1832;
and was also published in the Report of the Regents of the New
York University. A little more than a month later (to wit on
March 6, 1832,) he had been able to collate the various published
accounts of this aurora; and he learned "the fact of a dis-
turbance of terrestrial magnetism being observed by Mr. Christie
in England on the same evening, and at nearly the same time
the disturbance was witnessed in Albany, and that too in con-
nection with the appearance of an aurora." This circumstance
led him to make a careful comparison of the notices of auroral
displays given in the meteorological reports in the Annals of
Philosophy for 1830 and 1831, with those of the Reports of the
New York Regents for the same period. " By inspecting these
two publications it was seen that from April, 1830, to April, 1831,

* The neerlles employed in these observations were a couple received
by Professor Renwiok from Capt. Sabine, — one of which had belonged to
Prof. Hansteen of Norway. "They were suspended according to the
method of Hansteen in a small mahogany box, by a single fibre of raw
silk. The box was furnished with a glass cover, and had a graduated
arc of ivory on the bottom to mark the amplitude of the vibrations. In
using this apparatus, the time of three hundred vibrations was noted by
a qnarter-seuond watch, well regulated to mean time ; a register being
made at the end of every tenth vibration, and a mean deduced from the
whole, taken as the true time of the three hundred vibrations. Experi-
raents carefully made with this apparatus were found susceptible of con-
siderable accuracy : " the individual observations not differing from the
mean number, ordinarily more than one-thousandth. (Silliman's Am.
Jour. Sci. April, 1832, vol. xxii. p. 145.)

t Prof. Hansteen has remarked that " A short time before the aurora
borealis appears, the intensity of the magnetism of the earth is apt to rise
to an uncommon height; but so soon as the aurora borealis begins, in
proportion as its force increases, the intensity of the magnetism of the
earth decreases, recovering its former strength by degrees," often not till
the end of twenty-four hours." {Edinburgh Philosoph. .Tour. .Jan. 1825,
vol, xii. p. 91.)

46

PHILOSOPHICAL SOCIETY OF WASHINGTON. 213

inclusive, tlio aurora was remarkably frequent and brilliant both
in Europe and in this country ; and that most of the auroras
described in the Annals for this time, particularly the brilliant
ones, were seen on the same evening in England and in the State
of New York." From which he argues that " these simultaneous
appearances of the meteor in Europe and America would there-
fore seem to warrant the conclusion that the aurora borealis can-
not be classed among the ordinary local meteorological phenomena,
but that it must be referred to some cause connected with the
general physical principles of the globe ; and that the more
energetic action of this cause (whatever it may be) affects simul-
taneously a greater portion of the northern hemisphere." *

In attempting to classify and digest the meteorological data
within his reach, Henry became strongly impressed with the
necessity of much more extensive, continuous, and systematic
observations than any as yet undertaken : and he omitted no
opportunities of directing influence upon the minds of our
national legislators, to impress them with the great need — as
well as the practical policy of prosecuting the subject by govern-
mental resources. No one at that day seemed so fully awake
both to the importance and to the methods of prosecuting such
inquiry : and no one more effectually advanced both by direct
and by indirect exertions the wide-spread interest in this study,
than he.

In 1839, while at Princeton, he induced the American Philo-
sophical Society officially to memorialize the National Govern-
ment to establish stations for magnetic and meteorological obser-
vations : a movement which was partly successful, though not to
the extent desired. On the subject of international systems of
observation and register, he justly remarks at a later date : " In
order that the science of meteorology may be founded on reliable
data, and attain that rank which its importance demands, it is
necessary that extended systems of co-operation should be estab-
lished. In regard to climate, no part of the world is isolated :
that of the smallest island in the Pacific, is governed by the
general currents of the air and the waters of the ocean. To fully
understand therefore the causes which influence the climate of
any one country, or any one place, it will be necessary to study
the conditions, as to heat, moisture, and the movements of the
air, of all others. It is evident also that as far as possible, one
method should be adopted, and that instruments affording the
same indications under the same conditions should be employed.
. . . A general plan of this kind, for observing the meteor-
ological and magnetical changes, more extensively than had ever
before been projected, was digested by the British Association

* Sill. Am. Jour. Sci. April 1832, vol. xxii pp. 150-155.
VOL II. — 18 47

274: BULLETIN OF THE

in 1838, in which the principal governments of Europe were
induced to take an active part; and had that of the United
States, and those of South America, joined in the enterprise, a
series of watch-towers of nature would have been distributed
over every part of the earth." *

A. large collection of original notes of various meteorological
observations, — on magnetic variations, on auroras with attempts
at ascertaining their extreme height, on violent whirl-winds, on
hail-stones, on thunder-storms, and the deportment of lightning-
rods, — unfortunately never published nor transcribed were lost
(with much other precious scientific material) by a fire in 1865.
The phenomena of thunder-storms were always studied by Henry
with great interest and attention. A very severe one which
visited Princeton on the evening of July Hth 1841, was minutely
described in a communication to the American Philosophical
Society, November 5th, 1841. f

On November 3d, 1843, he made a communication to the
Society "in regard to the application of Melloni's thermo-electric
apparatus to meteorological purposes, and explained a modifica-
tion of the parts connected with the pile, to which he had been
led in the course of his researches. He had found the vapors
near the horizon, powerful reflectors of heat ; but in the case of a
distant thunder-storm, he had found that the cloud was colder
than the adjacent blue space. "|

On June 20, 1845, he read a paper before the Society on "a
simple method of protecting from lightning, buildings covered
with metallic roofs ;" urging the importance in such cases of
having the vertical rain pipes always in good electrical connec-
tion with the earth, since " on the principle of electrical induc-
tion, houses thus covered are evidently more liable to be struck
than those furnished either with shingle or tile." It is of course
necessary to have the metallic roof in good metallic connection
with the gutters and pipes ; and the latter may conveniently
have soldered to the lower end a ribbon of sheet copper two or
three inches wide, continuing into the ground surrounded with
charcoal and extending out from the house till it terminates in
moist ground. §

In this paper he incidentally meets the much debated question
whether a lightning-rod is efficient as a conductor by its solidity,

* Agricultural Report of Com. of Patents, for 1855, p. 367.

t Proceed. Am. Phil. Soc. vol. ii. pp. 111-11().

t Proceed. Am. Phil. Soc. vol. iv. p. 22.

§ Proceed. Am. Phil. Soc. vol. iv. p. 179. Heiirv appears to liave
been much impressed with the conducting value of tlie tinned sheet-iron
pipes commonly used as rain spouts, from observing that amid the strange
vagaries of the circuitous path pursued by the lightning (in cases of
houses struck by this destructive agent), the rain pipe was not nnfre-
qnently selected as part of the route ; — marks of explosive violence beiirg
exhibited at its lower end, und sometimes at its top as well.

48

PHILOSOPHICAL SOCIETY OF WASHINGTOX. 275

or b}" its surface only. While he had been able to magnetize
small needles placed transversely to the edges of broad strips of
copper, through which electrical discharges were passed, he could
obtain no signs of magnetism in needles when placed transversely
near the sides of such strips about mid-way from the edges. In
like manner he failed to discover any action in a small magne-
tizing helix placed within a section of gas-pipe and connected
with it at either end, when transmitting through the system an
electrical spark; while he easily obtained magnetic effects with
a galvanic current passed through the same arrangement.*
From these and other experiments he was led to believe that
mechanical electricity tends to pass mainly along the exterior
surface of a conductor, and accordingly tliat Ohm's law of con-
duction is not applicable to mechanical electricity. f

Some popular uneasiness having been excited in 184G, in con-
sequence of telegraph poles being occasionally struck by light-
ning, and of the supposed danger to travellers along highways
likely to result therefrom, a communication on the subject ad-
dressed to Dr. Patterson, one of the Vice-Presidents of the
American Philosophical Society, was read before the Society,
and referred to Professor Henry for report. This was in the
very infancy of the electro-magnetic telegraph ; as it had not
then been in existence more than a couple of years. Henry
responded in a communication read June 19th, 184(i, to the
effect that while telegraph wires as long conductors were emi-
nently liable to receive discliarges of atmospheric electricity
both from charged clouds and from the varying electrical condi-
tion of the air at distant points along the line (as for example
even by a fog or precipitation of vapor at one station) as also
from induction at a distance, the danger to travellers along a
telegraph road would be very slight, unless a person should be
standing or passing quite close to a pole at the moment of its
being struck. He however recommended that for the protection
of the poles, they should be provided with conductors. "The
effects of powerful discharges from the clouds may be prevented
in a great degree by erecting at intervals along the line and
beside the supporting poles a metallic wire connected with the
earth at the lower end, and terminating above at the distance of
about half an inch from the wire of the telegraph. By this

* In passing a galvanic current tlirongli an iron tnl>e. be obtained the
evidence of an induction from both the insi<le and the outside of tiie tube,
but in opposite directions.

t This very important question cannot be regarded as even yet de-
cisively settled : — eminent authorities maintaining that electricity in Jl,w
— of whatever origin — observes equally the ratio of proportionality to
area of cross section in the conductor. Probably the law of conductivity
varies with circumstances.

49

2TG BULLETIN OF THE

arrangement, the insulation of the conductor will not be inter-
fered'with, while the greater portion of the charge will be drawn
off. I think this precaution of great importance at places where
the line crosses a river and is supported on high poles. Also in
the vicinity of the office of the telegraph, where a dischage fall-
ing on the^vire near tlie station might send a current into the
house of sufficient quantity to produce serious accidents."* This
precaution has now been largely adopted, especially on the tele-
graph lines of the central portion of the United States, which are
more liable to the effects of lightning. f

3[oIecidar Physics. — Among other inquiries many original
examinations were made by Henry in the domain of molecular
physics. While Professor in the College of Xew Jersey in 1839,
his attention was attracted to a curious case of metallic capil-
larity. A small lead tube about eight inches long happening to
be left with a bent end lying in a shallow dish of mcrcmy, he
noticed a few days afterward that the mercury had disappeared
from the dish, and was spread on the shelf about the other end
of the tube. On a careful examination of the tube by incision,
it appeared that the mercury had not passed along the open canal
of the tube, but had percolated through its solid substance. To
test this, a solid rod of lead about one-fourth of an inch thick
and seven inches long was bent into a siphon form, and the
shorter end immersed in a small shallow vessel of mercury; a
similar empty vessel being placed under the longer end. In the
course of 24 hours a globule of mercury was found at the lower
end of the lead rod ; and in five or six days it had all passed
over excepting what appeared in the form of crystals of a lead
amalgam in the upper vessel.! A long piece of thick lead wire
was afterward suspended in a vertical position, with its lower
end dipping into a cup of mercury. In the course of a few days,
traces of the mercury were found in the rod at the height of
three feet above the cup : thus showing that a metal impervious
to water or oil (excepting under very great pressure) was easily
penetrated to great distances by a liquid metal.

Some years later on a visit to Philadelphia he endeavored with
the assistance of his friend Dr. Patterson (then Director of the
United States Mint), by melting a small globule of gold on a
plate of clean sheet-iron, to obtain its capillary absorption ; but
without effect ; probably owing to the interposition of a thin film
of oxide. Applving to another personal friend, Mr. Cornelius
(.f Philadelphia .'a very intelligent and ingenious manufacturer
uf bronzes, and plated ornaments for chandeliers, etc. to try

* Proceed. Am. Phil. Soc , vol. iv. p. 266.

t Prescott. Electricity and the Electric Telegraph, 8vo. N. York, 18 < 7,
ihap. xxiii. pp. 296. and 411.

J Proceed. Am. Pliil. Soc, vol. i. p. 82,

50

PHILOSOPHICAL SOCIETY OP WASHINGTON. 277

whether a i)iece of silver-plated copper heated to the melting
point of silver would show any absorption of that metal, he
learned that it was a common experience under such circumstances
to find the silver disappear; but that this had always been at-
tributed to a volatilization of the silver, or in the workman's
phrase, — to its being "burnt off." At Henry's request the expe-
riment was tried : the heated end of a silver-plated piece of
copper exhibited on cooling and cleaning, a copper surface, the
other end remaining unchanged. Henry next had the copper
surface slightly dissolved off by immersion for a few minutes in a
solution of muriate of zinc, when as he had anticipated, the
silver was again exposed, having penetrated to but a very short
and tolerably uniform distance below the original surface.*

In 1844, he made some important observations on the cohesion
of liquids. Notwithstanding that Dr. Young early in the century
maintained that " the immediate cause of solidity as distinguished
from liquidity is the lateral aclheaion of the particles to each
other," and had shown that " the resistance of ice to extension
or compression is found by experiment to differ very little from
that of water contained in a vessel, "f all the most popular text-
books on physics continued to teach that the cohesion of the
liquid state is intermediate between that of the solid and the
gaseous states. | It seemed therefore desirable to test the ques-
tion by some more direct means than the resistance of liquids
contained in closed vessels ; and for this purpose Henry em-
ployed the classical soap-bubble. " The effect of dissolving the
soap in the water is not as might at first appear, to increase the
molecular attraction, but to diminish the mobility of the mole-
cules." In fact the actual tenacity of pure water is greater than
that of soap-water.

The first sot of experiments was directed to determine "the
quantity of water which adhered to a bubble just before it burst."
The second set of experiments w^as devised to measure the con-
tractile force of a soap-bubble blown on the wider end of a U
shaped glass tube half filled with water, by the barometric column
sustained in the narrower stem of the tube ; the difference of
level being carefully observed by means of a microscope. The
thickness of the soap-bubble film at its top was estimated by the

* Proceed. Am. Phil. Soc. June 20, 184.5, vol, iv. p. 177.
f Young's Lectures on Nat. Philos. Lect. 50, vol. i. p. (j27.
X " If we attempt to draw up from the surface of water a circular disk
of metal say of an inch in diameter, we shall see that the water will

merely indicates the force of attraction of a single film of atoms around
the perpendicular surface, and not of the whole column elevated.'
(^Agricultural Report for 1857, p. 427.— Paper on lMt-t^orology )

278 BULLETIN OF THE

last of the Newton rings shown previous to bursting. The result
arrived at from both sets of exjieriments was that water instead
of having a cohesion of 53 grains to the square inch (as was
very commonly stated), has a cohesive force of several hundred
pounds to the inch ; or that the intermolecular cohesion of a
Mquid is fully equal to that of the substance in the solid state.*

In 1846, he presented to the Philosophical Society an epitome
of his views on the molecular constitution of matter; giving the
reasons for accepting the atomic hypothesis of Newton. He
pointed out that the discovery and establishment of a general
scientific principle " is in almost all cases the result of deductions
from a rational antecedent hypothesis, the product of the imagi-
nation ; founded it is true on a clear analogy with modes of
physical action, the truth of which have been established by
previous investigation :" and he urged that the hope of further
advancement lies in the assumption " that the same laws of force
and motion which govern the phenomena of the action of matter
in masses, pertains to the minutest atoms of these masses." He
therefore felt " obliged to assume the existence of an setherial
medium formed of atoms which are endowed with precisely the
same properties as those we have assigned to common matter."

" According to the foregoing rules we may assume with Newton,
the existence of one kind of matter diffused throughout all space,
and existing in four states, namely the setherial, the aeriform, the
liquid, and the solid. "f In referring to this postnlated fourfold
state of matter, Henry was accustomed to point out the remark-
able analogy between this conception, and that of the four ele-
ments of the ancients, — fire, air, water, and earth

" In conclusion, it should be remembered that the legitimate
use of speculations of this kind, is not to furnish plausible expla-

* Proceed. Am. Phil. Soc. April 5, and May 17, 1844, pp. 56, 57, and 84,
85. The original notes of these interesting experiments containing the
numerical results obtained under a great variety of comlitions, laid aside
for further redactions and comparisons, were destroyed by fire in 1865.
Since the density of most solid substances differs very slightly from that
of tlieir liquid state, being indeed less in many, — unless at considerably
lower temperatures, (as in tlie case of ice, and most of the metals.) it
appears quite improbable that the difference between solidity and liquidity
could depend in any case on the degree of cohesion. On the contrary,
the cohesion of water sliould be sensibly greater than that of ice, since its
constituent molecules are closer together. Of the nature of that "lateral
adhesion'^ which resists the flow of solids (excepting under the conditions
of great strain — long continued), and whose absence is mark d in liquids
by their almost perfect and frictionless mobility, our present science affords
us no intimation.

f Two hundred years ago, Newton speculating on the unity of matter,
ventured the suggestion, " Thus perhaps may all things be originated
from ffither." — Letter to the Secretary of the Royal Society — Henry Olden-
burg, January, 1676 {Hist, oj Roy. Soc. by Thomas Birch, vol. iii. p. 2o0).

52

PHILOSOPHICAL SOCIETY OP WASHINGTON. 219

nations of known phenomena, or to present old knowledge in a
new and more imposing dress, but to serve the higher purpose
of suggesting new experiments and new phenomena, and thus to
assist in enlarging the bounds of science, and extending the
power of mind over matter; and unless the hypothesis can be
employed in this way, however much ingenuity may have been
expended in its construction, it can only be considered as a scien-
tilic romance worse than useless, since it tends to satisfy the mind
with the semblance of truth, and thus to render truth itself less
an object of desire."*

Light and Heat. — Henry also made important investigations
on some peculiar phenomena connected with light and heat.
For the i)urpose of experimenting on sun light he devised in
1840, a very simple form of heliostat, based on the suggestion
of Dr. Young, whereby the solar ray was received into an upper
room in a direction parallel to the earth's axis, requiring there-
fore only an equatorial movement of the reflector; which was
effected "by the aid of a common cheap pocket watch placed on a
small hinged board set by a screw to the angle of latitude. The
mirror mounted on a swivel and properly balanced, presented
no sensible resistance to the running of the watch, which was
arranged for the 24 hour rotation by a watch-maker of Princeton.
Tlie whole cost of the completed instrument (including the time-
movement) was but sixteen dollars. If any particular direction
of the ray was required, it was only necessary to place a stationary
mirror in the fixed path of the ray, adjusted to the desired
angle, f

In 1841, on repeating experiments of Becquerel and Biot on
" Phosphorescence," he discovered some new characteristics in
the emanation (particularly when excited by electrical light)
which had not befpre been observed. | These were more fully
detailed in a communication made to the American Philosophical
Society, in 1843, "On Phosphorogenic Emanation.'' This phe-
nomenon had been first observed in the diamond, when taken into
a dark room immediately after exposure to direct sunlight, or
to a vivid electric spark ; and was afterward observed in several
other substances, — notably in the chloride of calcium — "Ilom-
berg's phosphorus. "§ It had also been shown by Becquerel that

* Proceed. Am. Phil. Son. Nov. 6, 1846, vol. W. pp. 287-290.

t Proceed. Am. Phil. Soc. Sept. 17, 1841, vol. ii. p. 97.

I Proceed. Am. Phil. Soc. April 16, 1841, vol ii. p. 46.

§ Ilomberg's phosphorus is chloride of caloium prepared by melting
one part of sal ammonia with two parts of slaked lime. Canton's phos-
phorus is sulphide of calcium formed by a mixture of three parts of
sifted and cahnned oyster shells, and one part of fiowerd of sulphur, ex-
posed for au hour to a strong heat.

53

280 BULLETIN OF THE

while this phosphorescence may be fully excited in the sensitive
body by rays which have passed through transparent sulphate
of lime, or through quartz, the effect is entirely arrested by a
plate of transparent mica, or glass. Henry by a long series of
experiments greatly extended these lists, including in them a
large number of liquids. He also subjected both the exciting
rays (especially of the electric spark) and the luminous emana-
tion, to various treatment, by reflection, refraction, polarization,
etc. The JS^icol prism was found to obstruct this peculiar ex-
citing ray so much as to permit scarcely any impression; but
what was remarkable and unexpected, a pile of thin mica plates
which seemed to cut off entirely the phusphorogeuic impression,
was found when placed obliquely at the best polarizing angle, to
distinctly excite a surviving luminous spot. On examination of
the phosphorescence excited by polarized light, no effect was
produced by a rotation of the analyser : " when the beam was
transmitted through crystals in different directions with reference
to their optical axis, no difference could be observed." The
phosphorescence was completely depolarized, as if taking an
entirely new origin in the sensiti\e substance: a fact re-dis-
covered by Professor Stokes some ten years later, with regard
to fluorescent emanations.

That the phosphorogenic effect does not depend on a heating
of the substance, appeared to be shown by the fact that "the
lime becomes as luminous under a plate of alum as under a plate
of rock-salt." The emanation was examined by a prism of rock-
crystal, and by one of rock-salt : — science had not then the spec-
troscope. While the impression could be readily made by a
reflected beam from a metallic mirror, it failed entirely when
directed from a looking-glass. The luminous eflect on the phos-
phorescent substance was found to be defined in location by the
form of the opening made in sheet metal screens. On testing
with different portions of the electric spark by means of a narrow
slit in the screen, tlie two terminals of the spark were found to
be much more active (as measured by the subsequent duration
of the phosphorescence) than the middle portion. By a suitable
arrangement of double screens with three slits each, he was able
to make simultaneous star-like photographs on the substance, of
the two extreme portions of the spark and of a middle point:
and while the latter point " exhibited a feeble phosphorescence
for two or three seconds" only, the two former "continued to
glow for more than a minute:" and yet the middle of the spark
appeared to the eye quite as vivid as its extremities. It was
also observed that while a sensitive daguerreotype plate received
no impression from the electric spark, inversely another similar
plate exposed for several minutes to the direct light of the fuU

54

PHILOSOPHICAL SOCIETY OF WASHINGTON. 281

moon received a pliotographie impression, while the lime simi-
larly exposed, exhibited no phosphorescence.*

Henry was afterward accustomed on the occurrence of a brig-ht
aurora, to expose a sheet of paper written or figured with a
solution of bisulphate of quinia to the auroral light, when the
characters (quite invisible by lamp-light or even by day-ligiit)
would distinctly glow with a pale blue light ; — indicating the
electrical nature of the meteor.

In January, 1845, in conjunction with Professor Stephen Alex-
ander, he instituted a series of experimental observations on the
relative heat-radiating power of the solar spots. On the 4th of
January a large spot through which our terrestrial globe could
have been freely dropped, (having been estimated at more than
10,000 miles in diameter,) favorably situated near the middle of
the disk, was examined with a telescope of four inches aperture.
A screen having been arranged in a dark room, with a thermo-
electric apparatus behind it and having its terminal or pile just
projecting through a hole in the screen, the image of the spot
was received upon it, giving a clearly defined outline about two
inches long and one inch and a half wide. By a slight motion
of the telescope the spot could readily be thrown on or off the
end of the pile as desired. A considerable number of observa-
tions indicated very clearly by the differing deflections of the
galvanometer needle " that the spot emitted less heat than the
surrounding parts of the luminous disk."f A brief account of
the results obtained by these researches given in a letter to his
friend Sir David Brewster, was read by him at the Cambridge
Meeting of the British Association in June, 1845. | The deter-
minations arrived at have been fully confirmed by the later obser-
vations of Secchi and others §

In 1845, he contributed a paper to the Princeton Review, on
"Color Blindness;" which although in the modest form of a
literary review of two Memoirs then recently published, (that of
Sir David Brewster in the Philosophical Magazine ; and that of

* Proceed. Am. Phil. Soc. May 26, 1843, vol. iii. pp. .38-44. This in-
teresting but obscure subject although apparently connected witli the
phenomenon of " fluorescence" has yet an entirely distinct phase in its
abnormal continuance of luminosity, — similar to the familiar efi"ect of a
thermal impression. It is possible however that the conversion of wave-
periodicity (wave-length), shown by Stokes to be the characteristic of
fluorescence, may require time for its full development.

t Proceed. Am. PhiL. Soc. June 20, 184.5, vol. iv. p. 176.

X Report Brit. Assoc. 1846, part 11. p. 6.

§ P. Angelo Secchi— during the years 1848, and 1849, was Professor of
Mathematics at the College of Georgetown, D. G. : and in the preparation
of his "Researches on Electrical Rheometry " published in the thir<l
volume of the Smithsonian Contributions, (ajt. ii. p. 60,) he received from
Henry the friendly assistance of apparatus and suirgestious. He was ap-
pointed Director of the Observatory at Rome, in 1850.

55

282 BULLETIN OF THE

Professor Elle Wartraan, of Lausanne, iu the ScientiBc Memoirs,)
supplied original observations on this interesting department of
the physiology of vision.

Miscellaneous Contributions. — Henry's miscellaneous contri-
butions to physical science are so numerous and varied, that only
a brief allusion to some of them can be afforded. In 1829, he
p iblished quite an elaborate " Topographical sketch of the State
t.f New York, designed chiefly to show the general elevations
and depressions of its surface."* And in later years he devoted
much attention to physical geography He performed at various
times, a good deal of chemical work (chiefly of an analytical
character), — first as Dr. T. Romeyn Beck's assistant,! and after-
ward independently, as well as mediately iu directing his own
))upils and assistants. In 1833, he devised an improvement of
Wollaston's mechanical scale of the chemical equivalents, for the
benefit of his pupils in chemistry: — a contrivance which was
much used and highly appreciated at the time.

The suggestion had been thrown out by more than one astro-
nomer, that carefully timed observations on characteristic meteors
or " shooting-stars" might be made available for determining
differences of longitude between the stations of observation. J
For many years however the proposition had been generally re-
garded as offering rather a speculative than a practical method of
solving a problem of so great nicety. Henry in concert with his
lirother-in-law, Professor Alexander, and witli his friend Professor
IJache, determined to ascertain by actual trial the availability and
value of the system. On the 25th of November, 1835, Professor
Bache observing at his residence in' Philadelphia (assisted by
I'rofessor J. P. Espy,) — simultaneously with Professor Henry
and Professor Alexander, at the Philosophical Hall at Princeton,
ihey obtained seven co-incidences: — the instant of disappearance
of the meteor being in each case selected as the most accurately
attainable epoch. Tliese seven observations (whose greatest dis-
crepancies amounted to but a trifle over 3 seconds) gave a mean
result of 2 minutes 0.61 second (^time longitude) differing only

* Tt-ans. Albany Institute, vol. i. pp. 87-112.

t "Henry was tht-n Dr. Beck's chemical a-^sistaiit, aud already an ad-
mirable experimentalist." Address before the Albany Institute, by Dr.
(». Meads, May 25, 1871. (Trans. Alhani/ Tnstit. vol. vii. p. 21.)

X ■' TiiH merit of first stigeesting the use of shooting stars and fire-balls
as signals for the determination of longitudes is claimed by Dr. Oll'ers and
the (rerman astronomers for L'enzenbeig, who published a work on the
!-ubject in 1802. Mr. Bailey however has pointed out a paper jiublishtfd
by Dr. Maskelyne twenty years previously, in which that illustrious
astronomer calls attention to the subject, and distinctly points out this
application of the phenomena.'' This was dated Greenwich, November
6ih, 1783. (/,. E. U. Phi. Mag. 1841, vol. xix. p. C54.)

51)

PHILOSOPHICAL SOCIETY OF WASHINGTON. 283

one second and two-tenths from the mean estimate of relative
longitude arrived at by other methods.*

Ill 1840, Henry gave an account of "electricity obtained from
a small ball partly filled with water, and heated by a lump."-}-

In 1843, be read a communication to the Society, " On a new
method of determining the velocity of Projectiles :" for this pur-
pose employing two screens of fine insulated wire each in circuit
with a galvanometer, and at determined near distances in the
path of the projectile; — whereby the galvanic currents would be
successively interrupted at the instants of penetration. To re-
cord the interval, each galvanometer needle is provided at one
end with a marking pen touching a horizontally revolving cylin-
der, which is divided by longitudinal lines into 100 ecjual parts,
and is driven by clock-work at the rate of ten revolutions per
second, giving therefore to the interval of passage between two
consecutive lines, the thousandth part of a second. | Another
still more ingenious method is suggested, whereby the galvano-
meter may be dispensed with: each circuit including an induc-
tion coil, one end of whose secondary circuit is connected with
the axis, and the other end placed very nearly in contact with
the surface of the graduated paper on the revolving cylinder,
so as to give the induction spark through the paper at the instant
of the interruption of the primary circuits by the projectile pass-
ing through the wire screens. This is really a much neater and
more direct application of the electric interruption than the em-
l)loyment of a galvanometer needle for making the record. If
desirable, the cylinder may be made to have a very slow longi-
tudinal movement by a screw, so as to give a helical direction to
the tracings ; and different pairs of screens similarly arranged at
distant points in the path of the projectile may be employed to
determine the variations of velocity in its flight.§

Henry was always a watchful student of psychological and
subjective phenomena. Vv'itnessing on one occasion the perform-
ance of an athlete before a large assembly, he noticed with a
curious interest the "inductive" sympathy manifested by nearly

* Proceed. Am. Phil. Soc. Dec. 20, 1839, vol. i. pp. 162, 1G3. "This
appears to have been the first actual determination of a difference of lon-
gitude by meteoric observations." (L. E. D. Phil. Mag. 1841, vol. xix.
p. 553.) Several years later (in 1838) similar meteoric observations were
made between Altoiia and Breslau ; and also between Rome and Naples.

t Proceed. Am. Phil. Soc. Dec. 18, 1840, vol. i. p. 323.

% It appears that Wlieatstone devised his ingenious electro-magnetic
" clironoscope" in 1840; though he unfortunately published no account
of it till 1845 ; or two years after the publication by Henry. And this
was called out as a leelamation, on the publication of a similar invention
by L. Brepuet, of Paris, in .January of the same year.
"§ Proceed. Am. Piul. S^c. May 3't, 1843, vol. iii. pp. 165-1G7.

5i

284 BULLETIN OF THE

every spectator (himself included) in being swayed by a move-
ment as of assistance to the performer. In remarking tbe impres-
sion of being moved, while steadily watching a series of passing
canal boats, — on each boat reaching a certain point, he referred
the impression (amounting almost to a sensation of movement),
to the relative angle of vision formed by the moving body.

He made a number of experiments on the flow of water jets
under varying conditions : also observations on sonorous flames
when passing into a stove-pipe of eight inches diameter and about
ten feet in length : on the comparative rates of evaporation from
fresh and from salt water: on the slow evaporation of water
from the end of a tube, and the much greater rapidity of evapo-
ration when the tube is open at both ends : extended notes of
which, with a great number of other researches, perished in the
flames.

In 1844, he published a Syllabus of his Lectures at Princeton.
In December of that year he presented to the Philosophical
Society a communication of a somewhat more theoretical charac-
ter than usual, — on the derivation and classification of mechanical
motors. He refers these to two classes ; — the first, those derived
from celestial disturbance (as water, tide, and wind powers), —
and the second, those derived from organic bodies or forces (as
steam and other heat powers, and animal powers). The forces
of gravity, cohesion, and chemical affinity are not included, since
these tend speedily to stable equilibrium ; and they become
sources of mechanical power only as they are disturbed by some
of those before mentioned. It is not the running down of the
water-fall, or the clock-weight, which is the true origin of their
useful work, but the lifting of them up. The same is true of the
power derived from combustion. He then adds that his second
class (the forces derived from the organic world) might perhaps
by a similar process of reasoning be derived from the first class ;
(that of celestial disturbance;) — regarding "animal power as
referable to the same sources as that from the combustion of
fuel," and the action of the vegetative power as "a force derived
from the divellent power of the sunbeam," being simply a case
of solar de-oxidation. Organism — vegetable and animal, he con-
siders as built up under the direction of a vital principle, which
is not itself a mechanical force. Volcanic power is neglected as
comparatively feeble and limited, and not practically utilized.*

* Proceed. Am. Phil. Soc. Dec. 20, 1844, vol. iv. pp. 127-129. Thi.s
appears lo be the first — as it is probably the best — analysis of physical
energy, which has been proposed. Twenty years later, a similar analysis
(with certainly no improvement in the classification) was adopted by
Prof. Tait, in an essay on '"Energy;" (North British Review, 1864, vol.
xl. art. iii. p. 191, of Am. edition:) and by Dr. Balfonr Stewart, in liis
Elem ntaiy Treatise on Unal, Oxford, 1806 (book iii. chap. v. art. 388, p.
354.)

58

PHILOSOPHICAL SOCIETY OF WASHINGTON. 285

This interesting digest presents one of the earliest and clearest
theoretical statements we have, of the correlation and transforma-
tion of the physical forces; including with these the so-called
organic forces.

ADMINISTRATION OF THE SMITHSONIAN INSTITUTION.

By an Act of Congress approved August 10, 184G, the liberal
bequest to the United tStates, for the promotion of Science, by
James Smithson of London, England, was appropriated to the
foundation of the Institution bearing his name ; the establish-
ment being made to comprise the chief dignitaries of the Govern-
ment as the supervising body, and a Board of Regents being
created for conducting the business of the Institution after com-
pleting its organization. As the testator had bequeathed his
fortune,* in simple terms "for the increase and diffusion of
knowledge among men," there arose not unnaturally a great
diversity of opinion both among Congressmen, and among the
Regents, as to the most desirable method of executing the pur-
pose of tlie Will : and the organizing Act was itself a sort of
compromise, after many years of discussion and disagreement in
I)Oth branches of Congress. To literary men, no instrument of
knowledge could be so important as an extensive Library : — to
the professional, a seat of education or public instruction — general
or special — supplemented bj elaborate courses of public lectures,
appeared the obvious and necessary means of diffusing useful
learning, — to the " practical," a large agricultural and poly-
technic institute — supplemented perhaps by a museum, was the
only fitting plan of developing the resources of our country : —
to the artistic, extensive galleries of art were the most worthy
and instructive objects of patronage. The Regents sought
counsel from the distinguished and the learned : and several of
them applied to Professor Henry for his opinion. He gave the
subject a careful consideration ; and announced very decided
views. As Smithson was a man of scientific culture, a Fellow
of the Royal Society, an expert analytical chemist, and devoted
to original research, Henry held that the language of his Will
must receive its most accurate and scientific and at the same
time most comprehensive interpretation; that the words "in-
crease and diffusion of knowledge among men" M-ere deliberately
and intelligently employed ; and that no local or even natjonal
interests were as broad as its terms, — that no merely educational
projects of whatever character, no schemes of material and
practical advancement however useful, could justly be regarded
as fulfilling the obvious intent — expressed by a scientific thinker

The whole amount of the bequest was a trifle over 100,000 pounds,

59

or about 54n,U00 dollars.

286 BULLETIN OF THE

and writer — first of all the increase of knowledge by the promo-
tion of original research, — the addition of new truths to the
existing stock of knowledge, and secondly — its widest possible
diffusion among mankind.*

These wise and far-reaching views exerted a marked influence;
and though hardly then in accord with the opinion of the majority,
yet led to his election Deceml)er 3d, 1846, as the "Secretary"
51 nd practical Director of the infant institution. A second time

was Henry called upon to sever dearly prized associations, the

prosperous and congenial pursuits of fourteen years within the
classic halls of Princeton. One motive turned the wavering
scale. Here was a rare occasion offered by the enlightened pro-
vision of James Smithson, to secure for abstract science and un-
promising original research, a much needed encouragement and
support; and an obligation upon the scientific few to resist and
if possible prevent the perversion of the trust to the merely
popular uses of the short-sighted many. That years would be
required for shaping the character and "conduct of the institution
as he desired, was certain ; — that this could not be effected
without much opposition and various obstacles, he very clearly
foresaw. That during these years of active supervision and
direction, he must abandon all hope of personal opportunity for
original research, be as freely accepted in the expressive remark
made to a trusted friend in consultation on the occasion : "If I
go, I shall probably exchange permanent fame for transient
reputation."

With the assurance of the Trustees of the College of New
Jersey, that should he fail to realize his programme, or should
he satisfactorily accomplish his apostolic purpose, his chair
should alwavs loe at his command, with a hearty welcome back,
Henry, neither spurred by over-confidence, nor depressed with
undue timidity, though filled with anxious solicitude for the
future, accepted the appointment tendered to him. He removed
with his family to Washington, and at once commenced his ad-
ministration of the duties assigned to him by the Kegents of the
Institution.

Summoned thus to the occupancy of a new and untried field,
and to the discharge of essentially executive functions, he from
the first displayed a clearness and promptness of judgment, a
singleness and steadiness of aim, a firmness and consistency of
decision, combined with a practical sagacity and moderation in
adapting his course to the exigencies of adverse conditions, which
stamped him as a most able and successful administrator. ^Vith-
out concealment and without diplomacy, his distiucth' avowed
principle of action was steadily and patiently pursued. With

* "Programme of Orgauization." Smithsonian Report tor lb47.

60

PHILOSOPHICAL SOCIETY OP WASHINGTON. 287

honest submission to the controlling Act of Congress, he made
as honest avowal of his desire and of his endeavor to have that
legislation modified. Hampered by provisions he deemed un-
wise and injurious, he yet skilfully managed to reconcile
contestant interests, and to secure the entire confidence and
concurrence of the Regents. Henceforth his purpose and his
effort were to be directed to the unique object of encouraging
and fostering the development of what has so flippantly been
designated "useless knowledge;" and merging self in the com-
munity of physical inquirers and collaborators, to become the
high-priest of abstract investigation ; — prepared to lend all prac-
ticable assistance to that small but earnest band of nature-
students, who inspired by no aims of material utility, seek from
their mistress as the only reward of their devotion, the higher
knowledge of truth.*

Of the two distinct objects of endowment specified by Smith-
sou's Will, — " the increase — and the diffusion — of knowledge,"
Henry forcibly remarked : " These though frequently con-
founded, are very different processes, and each may exist inde-
pendent of the other. While we rejoice that in our country
above all others, so much attention is paid to the diffusion of
knowledge, truth compels us to say that comparatively little
encouragement is given to its iyic7'ease.'\ There is another
division with regard to knowledge which Smithson does not
embrace in his design ; viz. the application of knowledge to use-
ful purposes in the arts. And it was not necessaiy he should
found an institution for this purpose. There are already in
every civilized country, establishments and patent laws for the
encouragement of this department of mental industry. As soon
as any branch of science can be brought to bear on the necessi-

* Henry has finely said : "Let censure or ridicnle fall elsewliere,— on
those whose lives are passed without labor and witliout ohjt'ct ; Vmt If t
praise and honor he bestowed on him who seeks with unwearied pafienoe
to develop the order, harmony, and beauty of pven the smallest part of
God's creation. A life devoted t-xclusively to tlie study of a single inset^t.
is not spent in vain. No animal however insignificant is isolated; it
forms a part of the great systeui of nature, and is governed by the samn
general laws which control the most prominent beings of the organic
world." {Sinithsonia7i Report for 18.55, p. 20.)

t Swainson the Naturalist, the countryman and friend of Smithson, hn's
very pointedly marked this recognized distinction. "The constitution of
the Zoological Society is of a very mixed nature, admirably adapte.l
indeed to the reigning taste. It is more calculated however to diffuse.
than to increase the actual stock of scientific knowledge." (^Discourse on
the Study of Natural History, Cabinet Cyclopaedia, 16mo. London, 18-34,
part iv. chap. i. sec. 221, p. 314.) And again: "It is very essenti-il
when we speak of the diflFusion or extension of science, that we do not
confound these stages of development with discovery or advancement ;
since the latter may be as different from the former as depth is from
shallowness." (Same work, part iv. chap. ii. sec. 240, p. 343.;

61

288 BULLETIN OF THE

ties, conveniences, or luxuries of life, it meets with encourage-
ment and reward. Xot so with the discovery of the incipient
principles of science. The investigations which lead to these,
receive no fostering care from Government, and are considered
by the superficial observer as trifles unworthy the attention of
those who place the supreme good in that which immediately
administers to the physical needs or luxuries of life. If physical
well-being were alone the object of existence, every avenue of
enjoyment should be explored to its utmost extent. But he who
loves truth for its own sake, feels that its highest claims are
lowered and its moral influence marred by being continually
summoned to the bar of immediate and palpable utility. Smith-
son himself had no such narrow views.* The prominent design
of his bequest is the promotion of abstract science. In this
respect the Institution holds an otherwise unoccupied place iu
this country ; and it adopts two fundamental maxims in its
policy ; — first to do nothing with its funds which can be equally
well done by other means ; and second to produce results which
as far as possible will benefit mankind in general." t

Congress — naturally with a prevailing tendency to the literary,
the showy, and the popular, had (after eight years of dilatory
controversy) directed in its organizing Act (sec. 5,) the erection
of a building " of suSicient size, and with suitable rooms or halls
for the reception and arrangement upon a liberal scale, of objects
of natural history including a geological and mineralogical
cabinet, also a chemical laboratory, a library, a gallery of art,
and the necessary lecture-rooms." By the "9th section of the
Act, the Board of Regents were authorized to expend the
remaining income of the endowment "as they shall deem best
suited for the promotion of the purpose of the testator." Out of
an annual income of some 40,000 dollars, the Regents in full
accord with their Secretary (whose carefully elaborated programme
they officially adopted December 1.3, 1847,) succeeded in credit-
ably inaugurating all the objects specified in the charter ; and
at the snme time in establishing the system of publication of
oriffinnl Memoirs, to which Henry justly attached the first im-
portance.

An incident in itself too slight to produce a visible ripple on
the current of Henry's life, is yet too characteristic to be here

^ * In reErard to tlip valne of scientific truth. SmitliPon in a cotnmnnicn-
tion dated .Tune lOtli 1824, has forcibly expressed hi>: strong " conviction
that it is in his l-iinirledge that man has found his srreatness and his
happiness, the high superiority which he holds over the other animals
who inhabit the earth with him ; and consequently that no ignorance is
probably without loss to him.no error withont pv?!." (Thomson's Annals
of Philnsnphi/, 1824. vol. xxiv. or new series vol. viii. p. 50.)
t Smithsonian Report for 1853, p. 8.

62

PHILOSOPHICAL SOCIETY OF WASHINGTON, 289

omitted. Dr. Robert Hare having in 1847 decided upon resign-
ing liis Professorsiiip of Chemistry in the Medical Department of
the University of Pennsylvania, (the largest and best patronized
in the country,) the vacant chair was tendered by the Board of
Trustees to Professor Henry. His friend Dr. Hare himself used
his influence to induce Henry to become his successor; particu-
larly dwelling on the large amount of leisure afforded for inde-
pendeut investigations. The income of this professorship was
more than double the salary of the Smithsonian Secretaryship.
The position tempting as it might have been under different
circumstances, was however declined. Henry felt that to leave
his present post before his cherished policy was fairly settled and
established, would be most jjrobably to abandon nearly all the
results of the experiment : and having set before himself the one
great object of directing the resources of the Smithsonian Insti-
tution as far as possible to the advancement of science, in con-
formity with the undoubted intention of its founder, (and as the
execution therefore of a sacred trust,) he resolutely put aside
every inducement that might divert him from the fulfillment of
his task.*

Of the half a dozen objects of attention specified in the 5th
section of the organizing Act, (the various inspiration of dif-
ferent partisans,) not one directly tended to further the primary
requirement of the Will : — even the Laboratory being avowedly
introduced simply as a utilitarian workshop for mining and agri-
cultural analysis. Regarded as methods of diffusing existing
knowledge they Avere obviously local and limited in their range :
and as compared with the instrumentality of the Press, were
certainly very inefficient for spreading the benefits of the endow-
ment among raen.f

* Some six years later, a ?oniewhat similar temptation was presented.
In 1853 on the resignation of President Carnalian of the College of New
Jersey at Princeton, an effort was made to induce the return of Professor
Henry to his academic seat, by a movement to obtain for him the Presi-
dency of the College. Such a token of affectionate remembrance could
not but be grateful and touching to his feelings ; but a sense of obligation
was upon him. not to he laid aside. He had nndertaken a work and a
responsibilitv which must not be left to the hazard of failure He declined
the proffered honor-with thanks ; and warmly recommended Dr Maclean
to the vacant position: who thereupon was duly elected. (Macleans
^/•.s/. or"' Co/^7e o/ iVrw .Tcw)/, vol ii. p. 336.) .^ ,, ■,

t "The object/specified in the Act of Congress evidently do not come
up to the idea of the testator as deduced from a critical examination of
his will. A library, a museum, a callery of arts, though important in
themselves, are local in their influence. I have from the beginning
advocated this opinion on all occasions, and shall continue to ad^o<^^^*;''
^l,P,iPVf,r a suitable opportunity occurs." ( Smilhsnninn Report for Inn- ,
p. 122 (of Senate edit.) p. 117. (of H. Rep. edit.) The superficial V^f^^}-
was not wantin? on tbf> part of some, that the words "increase and ml
fusion" were not to be taken too literally, but to be considered as the

VOL. II. — 19 63

290 BULLETIN OF THE

Henry with a rare courage dared maintain against most power-
ful influence, that the interests specitically designated must all
be subordinated to the fundamental requirement, the promotion
of original research for increasing knowledge ; and that this was
amply sustained by the residuary grant of authority to the Re-
gents (under the 9th section of the Act) "to make such disposal
as they shall deem best suited for the promotion of the purposes
of the testator, anything herein contained to the contrary not-
withstanding," of any income of the Smithsonian fund " not
herein appropriated, or not required for the purposes herein
provided." Henry's carefully studied programme comprised two
sections : the first, embracing the details of the plan for carrying
out the explicit purpose of Smitlison ; the second, indicating the
proper steps for carrying out the provisions of the Act of Con-
gress. The first and principal section proposed as methods of
promoting research, — the stimulation of particular investigations
by special premiums, — the publication of such original memoirs
furnishing positive additions to knowledge by exi)eriment and
observation as should be approved by a commission of experts
in each case, — the active direction of certain investigations by
the provision of instruments as well as of the necessary means,
the appropriations being judiciously varied in distribution from
year to year, — the prosecution of experimental determinations
and the solution of physical problems, — the extension of ethnology
(especially American) and in general the conduct of such varied
explorations as should ultimately result in a complete physical
atlas of the United States. As methods of promoting the diffu-
sion of knowledge, it was proposed to give a wide circulation to
the published original memoirs or Smithsonian " Contributions
to Knowledge" among domestic and foreign libraries, institutions,
and scientific correspondents, to have prepared by qualified col-
laborators, series of careful reports on the latest progress of
science in different departments, and to provide facilities for the
distribution and exchange of scientific memoirs generally.

It is unnecessary here to follow closely the slow steps by which
— through all the obstructions of narrow prejudice and ignorant
misconstruction, of selfish interest and pretended philanthropy,
of friendly remonstrance and hostile denunciation, — the policy
originally maiked out by the Secretary was with unwavering
resolution and imperturbable equanimity steadily pursued, until
it gained its assured success; the vindication and the unpreten-
tious triumph of "the just man tenacious of purpose."

The most formidable of the specialist schemes both in Congress

tautology of Iceal pquivaleiits, applicable to the devt'lopmpnt of thf' inrli-
vidual iiiinrl ; since school-boys (if not the pundits) were eviiieiitly
capable of an " increase " of knowledge.

64

PHILOSOPHICAL SOCIETY OF WASHINGTON, 291

and elsewhere, was that of the Library faction, which prosecuted
with remarkable zeal and energ}', threatened l)y the acknowledged
ability of its leading advocates to control the action of the
Regents, even to the neglect and abandonment of all the other
interests indicated by the statute. In Henry's judgment the In-
stitution should possess simply a working library,* an auxiliary
for those engaged in scientific research, a repertory well supplied
with the published Proceedings and Transactions of learned
Societies, but which so far from aiming at an encyclopaedic or a
literary character, should be mainly supplementary to the large
National Library already established at the Capital. " The
idea ought never to be entertained that the portion of the limited
income of the Smithsonian fund which can be devoted to the
purchase of books will ever be sufficient to meet the wants of
the American scholar. On the contrary it is the duty of this
Institution to increase those wants by pointing out new fields for
exploration, and by stimulating other researches than those which
are now cultivated. It is a part of that duty to make the value
of libraries more genci^ally known, and their want in this country
more generally felt."f

Processes of Divestment. — Henry's declaration that the mode-
rate means at command were insufficient to support worthily
either a Library, or a Museum, alone, was early justified. The
Library though slowly formed of only really valuable scientific
works, and this largely by exchanges with the Smithsonian publi-
cations,! in the course of a dozen years amounted to about
50,000 volumes : and the annual cost of binding, superinten-
dence, and the constant enlargement of room and of cases, was
becoming a serious tax upon the resources of the Institution. The
propriety of transferring the custody of this valuable and rapidly
increasing collection to the National Library established by
Congress, was repeatedly urged upon the attention of that body:

* To carry on the operations of tlie first section a working library will
be required, consisting of the past volumes of tlie transactions and pro-
ceedings of all the learned societies in every language. These are the
original sources from which the most important principles of the positive
knowledge of our day have been drawn." {Smithsonian Report for 1847, p.
139, of Sen. ed.: p. 131, of H. Rep. ed.)

t Smithsonian Report for 1858, p. 224, (of Sen. ed.) p. 216, (of H. Rep.
ed.)

i " It is the intention of tlie Regents to render the Smithsonian library
the most extensive and perfect collection of Transactions and scientific
works in tliis country, and this it will be enabled to accomplish by means
of its exchanges, wliich will furnish it with all the current journals and
publications of societies, while the separate series may be completed in
due time as opportunity and means may olfer. The Institution has al-
ready more complete sets of Transactions of learned societies than are to
be fo"und in the oldest libraries in the United States." {Smithsonian Re
port for 1855, p. 29.)

65

292 BULLETIN OF THE

and by an Act approved April 5th, 18G6, such transfer was at last
effected.

" Congress had presented to the Institution a portion of the
public reservation on which the building is situated. In the
planting of this with trees, nearly 10,009 dollars of the Smithson
income were expended." Ultimately however opportunity was
taken to have the Smithsonian park included in the general ap-
propriation by the Government for improving the public grounds.

The courses of Lectures which were continued from their
establishment in 1849, to 1863, were then abandoned. In con-
formity with the judicious policy entertained from the beginning
not to consume uuproGtably the limited means of the Institution
by attempting to do what could be as well or better accomplished
by other organizations, its herbarium comprising 30,000 botanical
specimens and other allied objects, was transferred to the custody
of the Agricultural Department. Its collection of anatomical
and osteological specimens was transferred to the Army Medical
Museum. And its Fine-Art collections were transferred to the
custody of the "Art-Gallery" established at Washington (with
a larger endowment than the whole Smithsonian fund) by the
enlightened liberality of Mr. W. W. Corcoran.

Such were the successive processes by which much of the early
and injudicious legislative work of organization, intended for
popularising the activities of the Institution, was gradually un-
done ; greatly to the dissatisfaction and foreboding of many of
its well-meaning friends. "It should be recollected," said Henry,
"that the Institution is not a popular establishment."*

TJie National Museum. — The last heritage of misdirected legis-
lation— the ^"ational Museum, still remains in nominal connection
with the Institution; although Congress has recognized the justice
of making special provision for its custody by an annual appro-
priation ever since its establishment in 1842, — four years before
the organization of the Smithsonian Institution. The Government
collection of curiosities had accumulated from the contributions of
the various exploring expeditions; and Henry from the first, had
objected to receiving it as a douation, foreseeing that it would

* Smithsonian Report for 1S76, p. 12. A distinguished politician, now
many years deceased, (an influential Member of Congress— and possible
statesman.) in the confidence of friendship pointed out with emphasis,
how by a few judicious expedients — involving only a moderate reduction
of the income of the Institution, golden opinions might be won from the
press, and the Smithsonian really be made quite a "popular" establit^h-
ment. Unseduced by these friendly suggestions of worldly wisdom, Henry
astonished his adviser by the smiling assurance that his self-imposed
mission and deliberate purpose was to prevent, as far as in hira lay, pre-
cisf'ly that consummation. Had the philosopher repudiated the "breath
of his nostrils" he could not have been lonked upon by tie politician, as
more hopelessly demented.

66

PHILOSOPHICAL SOCIETY OF WASHINGTON. 293

prove more than "the jrift of an elephant."* In his first Report,
he ventured to say: " It is hoped that in due time, other means
may be found of establishing and supporting a general collection
of objects of nature and art at the seat of the general government,
with funds not derived from the Smithsonian bequest. "f In his
third annual Report he remarked : " The formation of a Museum
of objects of nature and of art requires much caution. With a
given income to bo appropriated to the purpose, a time must
come when the cost of keeping the objects will just equal the
amount of the appropriation : after this no further increase can
take place. Also, the tendency of an Institution of this kind
unless guarded against, will be to expend its funds on a hetero-
geneous collection of ol)jects of mere curiosity." Justly jealous
of any dependence of the Institution, designed as a monument to
its founder, upon the varying favors or caprices of a political
government, or of any confusion between the National Museum,
and its own special collections for scientific study rather than for
popular display, he added: "If the Regents accept this Mu-
seum, it must be merged in the Smithsonian collections. It
could not be the intention of Congress that an Institution founded
by the liberality of a foreigner, and to which he has affixed his
own name, should be charged with the keeping of a separate
Museum, the property of the United States. . . The small
portion of our funds which can be devoted to a museum may be
better employed in collecting new objects, such as have not yet
beeo studied, than in preserving those from which the harvest of
discovery has already been fully gathered." Nor was he reconciled
to the gift by the suggestion that a suitable appropriation would
be granted by the National Government, for the expense of its
custody. " This would be equally objectionable ; since it would
annually bring the Institution before Congress as a supplicant
for government; patronage. "J

In his Report for 1851, he forcibly stated in regard to the
requirements of a general Museum, that "the whole income de-
voted to this object would be entirely inadequate :" and he
strongly urged a National establishment of the Museum on a
basis and a scale which should be an honor and a benefit to the
people and their Capital city. " Though the formation of a
general collection is neither within the means nor the province
of the Institution, it is an object which ought to engage the at-

* His friend Prof. Silliman in a letter dated December 4th, 1847, wrote :
■' If it is within tlie views of the Government to bestow the National
Museum upon tlie Smitlisonian Institution, the very bequest would seem
to draw after it an obligation to furnish the requisite accommodations
witliout taxinjr the Smithsonian funds : otherwise the gift might be de-
trimental instead of beneficial."

t Smilhonian Report, 1847, p. 139, (Sen. ed.), p. 132, (II. Rep. ed.)
i Smit/isonian Report for 1-49, pp. ISl, 182, (of Senate ed.) pp. 173,
174, (of H. Rep. ed.)

67

294 BULLETIN OF THE

tention of Congress. A general Museum appears to be a neces-
sary establishment at the seat of government of every civilized
nation. . . . An establishment of this kind can only be
supported by government; and the proposition ought never to be
encouraged of putting this duty on the limited though liberal
bequest of a foreigner."* This project was urged in almost
every subsequent Report. "There can be but little doubt that
in due time ample provision will be made for a Library and
Museum at the Capital of this Union, worthy of a government
whose perpetuity depends upon the virtue and intelligence of the
people. It is therefore unwise to hamper the more important
objects of this Institution by attempting to anticipate results
which will be eventually produced without the expenditure of its
means, "f " The importance of a collection at the seat of gov-
ernment, to illustrate the physical geography, natural history, and
ethnology, of the United States, cannot be too highly estimated :
but the support of such a collection ought not to be a burden
upon the Smitlisonian fund.''|

Tlie popular mind did not however appear to be prepared to
accept these earnest presentations; and in 1858, the National
Museum was transferred by law to the custody of the Smith-
sonian Institution, with the same annual appropriation (4,000
dollars) which had been granted to the United States Patent
OfiSce when in charge of it.

So rapidly were the treasures of the Museum increased by the
gathered fruits of various government explorations and surveys,
as well as by the voluntary contributions of the numerous and
wide-spread tributaries of the Institution, that the policy was
early adopted of freely distributing duplicate specimens to other
institutions where they would be most appreciated and most
usefully applied. And in this way the Smithsonian became a
valuable centre of diffusion of the means of investigation in
geology, mineralogy, botany, zoology and archgeology. The clear
foresight which announced that the Museum must very soon out-
grow the entire capacity of the Smithsonian resources, has been
most amply vindicated :§ and to-day a large Government Build-
ing is stored from basement to attic, with boxed up rarities of
art and nature, sufficient more than twice to fill the Smithsonian

* Smithsonian R.-porl for 1851, p. 227 (of Sen. ed.) p. 219, (of H. Rep.

ed.)

t Smithsonian Report, for 1852, p. 2.53, (of Seu. ed.) p. 245, (of IL

Rep. ed.)

t Smithsonian Report for 1853, p. 11, (of Sen. ed.) p. 9, (of H. Rep. ed.)
§ Although from the rapid growth of the national collection after it
was transferred to the custody of the Smithsonian Institution, the annual
appropriation of 4,000 dollars by Congress very soon became wholly in-
sufficient to defray even one-half its necessary expenses, it was not till
1871 that the appropriation was raised to 10.000 dollars. lu 1872, it was
increased to 15,000 dollars, and in 1874, to 20,000 dollars.

GS

PHILOSOrHlCAL SOCIETY OF WASHINGTON. 295

halls and galleries, in addition to their present overflowing dis-
play. The strong desire of Henry to see established in Wash-
ington a National Museum on a scale worthy of our resources,
and in which the existing overgrown collections might be so
beneficially exhibited, he did not live to see gratified. That the
realization of this wise and beneficent project is only a question
of time, is little doubtful ; and when established, its being and its
benefits will in no small degree be due to him who first realizing
its necessity, and most appreciating its importance, with un-
wearying perseverance for twenty-five years omitted no oppor-
tunity of urging upon members of Congress its importunate
claims.

Meteorological Work. — In the conduct of what were appro-
priately called the "active operations" of the Institution — under
the first section of the programme (in contradistinction to the
local and statical objects of the second section), a rare energy and
promptness were exhibited. The very first Report of the Secre-
tary announced not only the acceptance and preparation for pub-
lication of an elaborate work on explorations by Messrs. Squier
and Davis of "Ancient Monuments of the Mississippi Valley," but
the commencement of official preparations "for instituting various
lines of physical research. Among the subjects mentioned by
way of example in the programme, for the application of the
funds of the Institution, is terrestrial magnetism. . . . Another
subject of research mentioned in the programme, and which has
been urged upon the immediate attention of the Institution, is
that of an extensive system of meteorological observations, par-
ticularly with reference to the phenomena of American storms.
Of late years in our country more additions have been made to
meteorology than to any other branch of physical science. Seve-
ral important generalizations have been arrived at, and definite
theories proposed, which now enable us to direct our attention
with scientific precision to such points of observation as cannot
fail to reward us with new and interesting results. It is pro-
posed to organize a system of observations which shall extend as
far as possible over the North American continent. . . . The
present time appears to be peculiarly auspicious for commencing
an enterprise of the proposed kind. The citizens of the United
States are now scattered over every part of the southern and
western portion of Northern America, and the extended lines of
telegraph will furnish a ready means of warning the more north-
ern and eastern observers to be on the watch for the first appear-
ance of an advancing storm."*

* Smithsonian Report for 1847, pp. 146, 147, (of Sen. ed.), pp. 1S8, 139,
(of H, Rep. ed.) Prof. Loomis (to whom among others " distinguislied
for their attainments in nieteornloaiy" letters inviting sug-iestiouS, had
been addressed,) recommended that there should be at least one observing

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296 BULLETIN OF THE

An appropriation for the purpose having been made by the
Regents, a large number of observers scattered over the United
Slates and the Territories became voluntary correspondents of
the Institution. Advantage was taken of the stations already
established under the direction of the War, and of the Navy
Departments, as well as of those provided for by a few of the
States. The annual reports of the Secretary chronicled the
extension and success of the system adopted ; and in a few years
between five and six hundred regular observers were engaged in
its meteorological service. The favorite project of employing
the telegraph for obtaining simultaneous results over a large
area was at ouce organized; and in 1849, a system of telegraphic
despatches was established, by which (a few years later) the in-
formation received in Washington at the Smithsonian Institution
was daily plotted upon a large map of the United States by
means of adjustable symbols. Espy's generalization that the
principal storms and other atmospheric changes have an east-
ward movement,* was fully established by this rapidly gathered
experience of the Institution ; so that " it was often enabled to
predict (sometimes a day or two in advance) the approach of any
of the larger disturbances of the atmosphere. "f

Eminently eflScient as the enterprise approved itself, increasing
experience served to demonstrate the increasing demands of the
service; and it was seen that to prosecute the subject of meteor-
ology over so large a territory, with the fulness necessary, would
require a still larger force of observers, and a greater drain upon
the resource.s of the Institution, than could well be spared from
other objects ; and as the great value of the system was fully
recognized by the intelligent, the propriety of maintaining a
meteorological bureau by the national support was early pre-
sented to the attention of Congress. This most important depart-

station within every hundred square miles of the United States ; and he
sagaciously pointed out that " When the magnetic telegraph [then an
infant three years old] is extended from New York to New Orleans and
St. Louis, it may be made subservient to the protection of our com-
merce." Tills interesting letter was publishe'l in full as "Appendix No.
2," to the Report. In 1848, a paper was read before the British Associa-
tion by Mr. .John Bail, "On rendering the Electric Telegraph subservient
to Meteorological Research : in which the author suggested tliat simulta-
neous observations so collected, might reveal the direction and probable
time of arrival of storms. (^Report. Brit. Assoc. Swansea. Aug. 1848.
Abstracts, pp. 12, 13.)

* Franklin is said to have heen tlie first who stated the general law,
that the storms of our Southern States move off to the northeastward
over the Middle and Eastern States.

f Smithsonian Report for 18t;4, p. 44. An interesting and instructive
resume of results accomplished within fifteen years was given in this Re-
j'ort, pp. 4i-4j : and continued in the succeeding Report for 18(35, pp.
50-59.

70

PHILOSOPHICAL SOCIETY OP AVASHINGTON. 297

nient of observation had been advanced by Henry to that position,
ill vvliich a hirger annual outlay than the entire income of the
Institution was really required to give just efficiency to the sys-
tem. In bis Report for I8(i5, be remarked : " The present would
appear to be a favorable time to urge upon Congress the import-
ance of making provision for the reorganizing all the meteoro-
logical observations of the United States under one combined
plan, in which the records should be sent to a central depot for
reduction, discussion, and final publication. An appropriation
of 50,000 dollars annually for this purpose would tend not only
to advance the material interest of the country, but also to in-
crease its reputation. . . . It is scarcely necessary at this day
to dwell on the advantages which result from such systems of
combined observations as those which the principal governments
of Europe have established, and are now constantly extending."*
P^ive years later, in support of the proposition that the subject
from its magnitude now appealed to the liberality of the nation,
he briefly recapitulated the work accomplished by the limited
means of the Institution. "The Smithsonian meteorological
system was commenced in 1849, and has continued in operation
until the present time. ... It has done good service to the
cause of meteorology ; 1st in inaugurating the system which has
been in operation upwards of twenty years : 2nd in the introduc-
tion of improved instruments after discussion and experiments :
3i'd in preparing and publishing at its expense an extensive series
of meteorological tables : 4th in reducing and discussing the
meteorological material which could be obtained from all the
records from the first settlement of the country till within a few
years: 5th in being the first to show the practicability of tele-
graphic weather signals : fith in ])ublishing records and discus-
sions made at its own expense, of the Arctic expeditions of Kane,
Hayes, and McClintock: Tth in discussing and pulilishing a
number of series of special records embracing periods of from
twenty to fifty years in different sections of the United States, —
of great interest in determining secular changes of the climate :
8th in the publication of a series of memoirs on various meteoro-
logical phenomena, emln-acing observations and discussions of
storms, tornadoes, meteors, auroras, etc. : 9th in a diffusion of a
knowledge of meteorology throngh its extensive unpul)lished
correspondence and its printed circulars. It has done all in this
line which its limited means would permit ; and has urged upon
Congress the establishment with adequate appropriation of funds,
of a meteorological department under one comprehensive plan,
' in which the records should be sent to a central depot for reduc-
tion, discussion, and final publication.' "f

* Smithsonian Report for 1865, p. 57.
f Smithsonian Report for 1870, p. 43.

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298 BULLETIN OF THE

In 1870, a meteorological departmeut was established by the
Governiueut under the Signal Office of the War Department,
with enlarged facilities for systematic observation : and agree-
ably to the settled policy of the Institution, this important field
of research was in 1872, abandoned in favor of the new organiza-
tion.* Of the voluminous results of nearly a quarter of a cen-
tury of systematic records over a wide geographical area which
have been slowly digested and laboriously discussed, only a
small portion has yet been published. The publication of'^the
series when practicable, will yet prove an inestimable boon to
meteorological theory.

Although our country can boast of many able meteorologists,
who have greatly promoted our knowledge of the laws of atmos-
pheric phenomena, it is safe to say that to no single worker in the
field is our nation more indebted for the advancement of this
branch of science to its present standing, than to Joseph Henry.
Quite as much by his incitement and encouragement of others
in such researches, as by his own exertions, does he merit this
award. To him is undoubtedly due the most inii)ortant step in
the modern system of observation, — the installation of the tele-
graph in the service of meteorological signals and predictions. f
While giving however his active supervision to the extensive
system he had himself inaugurated, publishing many important
reductions of particular features, as well as various circulars of
detailed instructions to observers, of the desiderata to be obtained
by those having the opportunities of arctic, oceanic, and south-
ern explorations, directing the constant observations recorded at
the Institution as an independent station, he made many per-
sonal investigations of allied subjects; — as of the Aurora, of
Atmospheric electricity and Thunder-storms, of the supposed
influence of the Moon on the weather, — and contributed a valu-
able series of Memoirs on Meteorology, embracing a wide range
of physical exposition, to the successive Agricultural Reports of
the Commissioner of Patents, during the years 1855, '56, '57,

* As an illustration of the popular favor iu wliicla this Signal service
is held, it may be stated that the annual appropriation hy Government
for its support now exceeds not merely the entire Smithsonian income,
but sixteen times that amount; or in fact its whole endowment.

f " However frequently the idea may have been suggested of utilizing
our knowledge by the employment of the electric telegraph, it is to Pro-
fessor Henry and his assistants in the Smithsonian Institution that the
credit is due of havinsr first actually realized this suggestion. ... It
will thus be seen that without material aid from the Government, but
through the enlightened policy of the telegraph companies, the Smith-
sonian Institution ^first in the world orj;anized a corapreheusire system of
telegraphic meteorology, and has thus given — first to Europe and Asia,
and now to the United States, that most beneficent national application
of modern science — the Storm Warnings." Article on " Weather Tele-
graphy" by Prof. Cleveland Abbe. {Am. Jour. Hci., Aug. 1871, vol. ii.
pp. 83, 85.)

72

'■ PHILOSOPHICAL SOCIETY OF WASHINGTON. 299

'58, and 1S59. Instructive articles on Magnetism and Meteor-
ology were prepared in 18G1 for the American Encyclopaedia.
And as an illustration of his continued interest in such studies,
one of his latest published papers comprised a minute account of
tlie effects of lightning in two thunder-storms ; one occurring in
the spring of last year (1877) at a Light-house in Key West,
Florida, and the other occurring in the summer of last year at
New London, Connecticut.*

ArcTiseological Work. — One of the earliest subjects taken
up for investigation by the Institution, was tliat of American
Archaeology ; the attempt by extended explorations of tlie exist-
ing pre-historic relics, mounds, and monuments, of the abori-
gines of our country, to ascertain as far as possible their primi-
tive industrial, social and intellectual character, and any evidences
ot their antiquity, or of their stages of development. The first
publication of " Smithsonian Contributions" comprised in a good
sized quarto volume an account of extensive examinations of the
mounds and earthworks found over the broad valley of the Mis-
sissippi, with elaborate illustrations of the relics and results
obtained : and this volume extensively circulated by gift and by
sale, attracted a wide-spread attention and interest, and gave a
remarkable stimulus to the further prosecution of such researches.
" Whatever relates to the nature of man is interesting to the
students of every branch of knowledge ; and hence ethnology
affords a common ground on which the cultivators of physical
science, of natural history, of archaeology, of language, of his-
tory, and of literature, can all harmoniously labor. Consequently
no part of the operations of this Institution has been more gen-
erally popular than that which relates to this subject, "f

Special explorations inaugurated by the Institution, have sup-
plied it with important contributions to archaeological informa-
tion, and with the rich spoils of collected relics ; which together
with much material gathered from Arctic and from Southern
regions, from Europe, from Asia, and from Africa, fill now a
large museum hall 200 feet long and 50 feet wide, exclusively
devoted to comparative Anthropology and Ethnology. In 1868,
the Secretary reported that "during the past year greater effort
has been made than ever before to collect specimens to illustrate
the ethnology and archaeology of the North American conti-
nent :" and he dwelt upon the importance of the subject as a
study connecting all portions of the habitable earth, pointing
out that "it embraces not only the natural history and pecu-
liarities of the different races of men as they now exist upon the

* Journal of the American Eleclrirnl Society, 1878, vol. ii. pp. 37-43.
TliH communication is dated Oct. 13, 1877 ; tliuugli not piiLlisheil till
tlnringf his last illness.

I Siiiithsonian Report for 1830, p. 38.

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300 BULLETIN OF THE

globe, but also their affiliations, their changes in mental and
moral development, and also the question of the geological epoch
of the appearance of man upon the earth. . . . The ethnologi-
cal specimens we have mentioned are not considered as mei-e
curiosities collected to excite the wonder of the illiterate, but as
contributions to the materials from which it will be practicable
to reconstruct by analogy and strict deduction, the history of the
past in its relation to the present."*

Two years later he reported: "The collection of objects to
illustrate anthropology now in possession of the Institution is
ahnost unsurpassed, especially in those which relate to the present
Indians and the more ancient inhabitants of the American conti-
tinent." Deprecating the frequent dissipation of small private col-
lections of such objects at the death of their owners, he forcibly
urges that " the only way in which they can become of real im-
portance, is by making them part of a general collection, care-
fully preserved in some public institution, where in the course of
the increasing light of science, they may be made to reveal truths
beyond present anticipation. "f

In his last Report — for 1877, — just published (and which he
did not live to see in print), he says : " Anthropology, or what
may be considered the natural history of man, is at present the
most popular branch of science. It absorbs a large share of
public attention, and many original investigators are assiduously
devoted to it. Its object is to reconstruct as it were the past
history of man, to determine his specific peculiarities and general
tendencies. It has already established the fact that a remark-
able similarity exists in the archaeological instruments found in
all parts of the world, with those in use among tribes still in a
savage or barbarous condition. The conclusion is supported by
evidence which can scarcely be doubted, that by thorouglily
studying the manners and customs of savages and the instru-
ments employed by them, we obtain a knowledge of the earliest
history of nations which have attained the highest civilization.
It is remarkable in how many cases, customs existing among
highly civilized peoples are found to be survivals of ancient
habits." He then argues from the significance thus developed
of many trivial practices and unmeaning ceremonies handed
down from immemorial time, the importance to a full compre-
hension of the customs of modern society, of a scientific study
of the myths and usages of ancient peoples. " American anthro-
pology," he remarks, "early occupied the attention of the Smith-
sonian Institution ;" and alluding to its first published work, he
says "from the time of the publication of this volume until the
present, contributions of value have been made annually by the

* Smilhsomnn Report for 1868, pp. 26 anrl 33.
^ I Smithsonian Report for 1870, pp. 35, 36.

74

PHILOSOPHICAL SOCIETY OF WASHINGTON. 301

Institution to this brancli of knowledge The collection

of the archasology and ethnology of America, in the National
Museum, is the most extensive in the world : and in order to
connect it permanently with the name of Smithson, it has been
thought advisable to prepare and publish at the expense of the
Smithsonian fund, an exhaustive work on American anthropology,
in which the various classes of specimens shall be figured and
described."* This great work still remains to be perfected.

Publications. — To attempt the recapitulation of the various
branches of original research initiated or directly fostered by
the Institution, would be to write its history. The range and
variety of its active operations, and the value of their fruits, are
in view of the limited income, and the collateral drains of less
important objects exacted from it, something quite surprising.
Scarcely a department of investigation has not received either
directly or indirectly liberal and efficient assistance : and a host
of physicists in the successful prosecution of their diverse labors,
have attested their gratitude to the Institution, and no less to
the ever sympathetic encouragement of its Director.

Over one hundred important original Memoirs, generally too
elaborate to be published at length by any existing scientific so-
ciety, issued in editions many times larger than the most liberal
of any such society's issue, most of them now universally recog-
nized as classical and original authorities on their respective
topics, forming twenty-one large quarto volumes of " Smith-
sojJiAN Contributions to Knowledge," distributed over every
portion of the civilized or colonized world, constitute a monu-
ment to the memory of the founder, James Smithson, such as
never before was builded with the outlay of one hundred thou-
sand pounds: and before which the popular Lyceums of our lead-
ing cities, with endowments averaging double this amount, pale
into insignificance.

Such as these Lyceums with their local culture, admirable
and invaluable in their way, but exerting no influence upon the
progress of science, or outside of their own communities, and
scaiTely known beyond their cities' walls,— such was the type of
institute which early legislators could alone imagine. Such as
the " Smithsonian Institution" stands to-day,— such is the mon-
ument mainly constructed by the foresight, the wisdom, and the
resolution of Henry.f All' honor to the Regents, who with

* SmHyonian Report for 1877. pp. -2, 23. Circulars broadly distrib-
uted by tbe Institution, bave served to give desired direction to popular
attention and activity in this field of research ; and the extent of co-
operation is such as probably only the "Smitbscnian" could have se-
cured, unless by a vastly greater outlay.

f "It is not by its castellated buildincf, nor tbe exhibition of tbe mu-
seuui of the Government, that the Institution has achieved its present

75

302 BULLETIN OF THE

an enlightenment so far in advance of tlie ruling intelligence of
former clays, and against the pressures of overwhelming prepon-
derance of even educated popular sentiment, courageously adopted
the programme of the Secretary and Director they had appointed ;
and who throughout his career, so wisely, nobly, and steadfastly
upheld his policy and his purpose.

Fifteen octavo volumes of " Smithsonian Miscellaneous Collec-
tions" of a more technical character than the "Contributions,"
(including systematic and statistical compilations, scientific sum-
maries, and valuable accessions of tabular "constants,") form in
themselves an additional series ; and represent a work of which
any learned Society or Institution might well be proud. And
thirty octavo volumes of annual Reports, rich with the scattered
thoughts and hopes and wishes of the Director, form the official
journal of his administration.

The Bibliography of Science. — Among the needful prepara-
tions for conducting original inquiry, none is more important than
ready access and direction to the existing state of research in
the particular field, or its allied districts. This information is
scattered in the thousands of volumes which form the transactions
of learned Societies ; and its acquisition involves therefore in
most cases a very laborious preliminary bibliographical research.
To make this vast store of observation available to scientific
students, by the directory of well arranged digests, would appear
to fall peculiarly within the province of an Institution specially
established for promoting the increase and diffusion of knowledge
among men ; and was early an object of particular interest to
Henry. In his Report for 1851, he remarked: "One of the most
important means of facilitating the use of libraries (particularly
with reference to science,) is well digested indexes of subjects,
not merel}'' referring to volumes or books, but to memoirs, papers,
and parts of scientific transactions and systematic works. As an
example of this, I would refer to the admirably arranged and
valuable catalogue of books relating to Natural Philosophy and
the Mechanic Arts, by Dr. Young. This work comes down to
1807 ; and I know of no richer gift which could be bestowed upon
the science of our own day, than the continuation of this catalogue
to the present time. Every one who is desirous of enlarging the

r<»putation ; nor by the collection and display of material objects of any
kind, that it has vindicated the intelliience and good faith of the Gov-
ernment in the administration of the trust. It is by its explorations, its
researches, its pnblieations, its distribution of spt-cimens, and its ex-
clianges, constituting it an active livinj:; organization, that it has rendered
itself favorably known in every part of the civilized world ; has made con-
tiibutious to almost every branch of science ; and brou^'ht, more than ever
before, into intimate and Iriendly relations, the Old and the New Worlds."
(Memorial to Congress, by Chancellor S. P. Chase, and Secretary Joseph
Henry. Smithsonian Report, for 1867, p. 114.)

76

PHILOSOPHICAL SOCIETY OF WASHINGTON. 303

bounds of human knowledge, should injustice to himself as well
as to the public, be acquainted with what has previously been
done in the same line; and this he will only be enabled to accom-
plish by tlie use of iudexes of the kind above mentioned."*

At the time, and for years afterward, one-half of the Smith-
sonian income was diverted by the requirements of Congress
to the local objects of the Lyceum: and the hopelessness of
attempting a work — additional to that already mapped out,
which would require the united labors of a large corps of well-
trained and educated assistants for many years, and the subse-
quent devotion of the whole available income for many years
following, to complete its publication, was fully realized. The
project however was not abandoned : and in 1854, Henry con-
ceived the plan of taking up the more limited department of
American Scientific Bibliography ; and by the persevering ap-
plication of a fi.xed portion of the income annually for a suc-
cession of years, of finally producing a thorough subject-matter
index, as well as an index of authors, for the entire range of
American contributions to science from their earliest date. In-
spired with tiiis ambition, he sought to enlist the co-operatiou
of the British Association for the Advancement of Science, in
procuring with its large resources, a similar classified index for
British and European scientific literature.

The favorable reception of this project, was officially announced
to Henry by the Secretary of the Association, in the transmis-
sion of the following extract from the proceedings of that body
for 1855. "A communication from Professor Henry of Washing-
ton having been read, containing a proposal for the publication
of a catalogue of philosophical memoirs scattered throughout the
Transactions of Societies in Europe and America, with the offer
of co-operation on the part of the Smithsonian Institution, to
the extent of preparing and publishing in accordance with the
general plan which might be adopted by the British Association,
a catalogue of all the American memoirs on physical science, —
the Committee approve of the suggestion, and recommend that
Mr. Cayley, Mr. Grant, and Professor Stokes be appointed a
committee to consider the best system of arrangement, and to
report thereon to the council."! The report of this committee
dated 13th June, 1856, was presented to the succeeding Meeting
of the British Association ; in which they take occasion to say:
" The Committee are desirous of expressing their sense of the
great importance and increasing need of such a catalogue.
The catalogue should not be restricted to memoirs in Transac-
tions of Societies, but should comprise also memoirs in the Pro-
ceedings of Societies, in mathematical and scientific journals:"

Smityoninn Report inr 1851. p. 225 (of Sen. ed.). p. 217 (of H Rep. ed.)
Report Brit. Ansoc. Glasgow, Sept. 18 5, p. Ixvi.

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304 BULLETIN OF THE

etc. . . "The catalogue should begin from the year 1800.
There should be a catalogue according to the names of authors,
and also a catalogue according to subjects."* The Committee
comprising Fellows of the Ro3'al Society of London finally suc-
ceeded in interesting that grave body in the undertaking : and
the result was that greatly to Henry's satisfaction, the entire
work was ultimately assumed by the Royal Society itself.

In the course of ten years that liberal Society aided by a large
jrrant from the British Government gave to the world its half
instalment of the great work, in its admirable " Catalogue of
Scientific Papers" alphabetically classified by authors, in seven
or eight large quarto volumes. In the Preface to this splendid
monument of industry and liberality, stands the following history
of its inception. " The present undertaking may be said to have
originated in a communication from Dr. Joseph Henry, Secretary
of the Smithsonian Institution, to the Meeting of the British
Association at Glasgow in 1855, suggesting the formation of a
catalogue of Philosophical memoirs : this suggestion was favor-
ably reported on by a Committee of the Association in the fol-
lowing year. . . . In March, 1857, General Sabine, the
Treasurer and Vice-President of the Royal Society, brought the
matter before the President and Council of that body, and re-
quested on the part of the British Association, the co-operation
of the Royal Society in the project : whereupon a committee was
appointed to take into further consideration the formation of
such a Catalogue. ... No further step was taken by the
British Association or by the Royal Society in co-operation with
that body: but the President and Council of the Royal Society
acting on the recommendations contained in a Report of the
Library Committee dated 1th January, 1858, resolved that the
preparation of a Catalogue of scientific memoirs should be under-
taken by the Royal Society independently, and at the Society's
own charge."!

System of Exchanges.— Tor the diffusion of knowledge among
men, one of the methods adopted by Henry from the very com-
mencement of his administration was the organization of a sys-
tem by which the scientific memoirs of Societies or of individuals
from any portion of the United States, might be transmitted to
foreign countries without expense to the senders : and by which

* Rppnrt Brit. Asxoc. Cheltenham, Auor. 1856, pp. 4'i3, 464.

t Preface to Catalogue, of Scientific Papers, (lSOO-1863) vol. i. 1867, pp.
iii., iv. The second and most important division of this etreat and invalu
able work,— the classified Index to Subjects,— still remains to be accom-
plished. Had the plan adopted been made to include the scientific
memoirs of the two preceding centuries, the value of the compilation
would have been enhanced in a far greater proportion than the additional
expenditure or the increase of bulk.

78

PHILOSOPHICAL SOCIETY OF WASHINGTON. 305

in like manner the similar publications of scientific work abroad
might be received at the Smithsonian Institution, for distribution
in this country. This privilege however is properly restricted
to bona fide donations and exchanges of scientific memoirs; — all
purchased publications being carefully excluded and left to find
their legitimate channels of trade. By an international courtesy
— creditable to the wisdom and intelligence of the civilized
Powers, — such packages to and from the Institution are per-
mitted to pass through all Custom-houses, free of duty; an
invoice of authentication being forwarded in advance. When
it is considered that this large work of collection and distribution
(including the constant supply of the Institution's own publica-
tions, and the extensive returns therefor of journals, proceedings,
and transactions, for its own library) requires the systematic
records and accounts in suitable ledgers, with the accurate par-
celling and labelling of packages, large and small, to every
corner of the globe, it may well be conceived that no small
amount of labor and expense is involved in these forwarding
operations.* A recognition of the benefits conferred by this
generous enterprise, is practically indicated by the rapid enlarge-
ment of the operations. The weight of matter sent abroad by
the Institution at the end of the first decade, was 14 thousand
pounds for the year 1857 : the weight sent at the end of the
second decade, was 22 thousand pounds for the year 18fi7 : and
the weight sent at the end of the third decade, was 99 thousand
pounds for the last year 1877. This admirable system has been
greatly encouraged and facilitated by the most praiseworthy
liberality of the great lines of ocean steamers, and of the lead-
ing railway companies, in carrying the Smithsonian freight in
many cases free of charge, or in other cases at greatly reduced
rates : an appreciative tribute alike to the beneficent services
and reputation of the Institution, and to the personal character
and influence of its Director.f

* It may be stated that the number of foreign institutions and corre-
spondents receiving the Smithsonian publications exceeds two thousand ;
whose localities embrace not only the principal cities of Europe (from
Iceland to Turkey), of British America, Mexico, the West Indies, Central
and South America, and of Australia, but also those of New Zealand,
Honolulu in the Sandwich Islands, twelve cities in India, Shanghai in
China, Tokio, Yedo, and Yokohama, in .Japan, Batavia in .Java, Manilla
in the Philippine Islands, Alexandria and Cairo in Egypt, Algiers in
northern Africa, Monrovia in Liberia, and Cape Town in southern Africa.
The CO respondents and recipients in the United States, are probably
nearly as nuiuerotis.

t " The cost of this system would far exceed the mf^ans of the Institu-
tion, were it not for important aid received from various parties interestt^ I
in facilitating international intercourse and the promotion of friendly
relations between distant parts of the civilized world. The liberal aid
extended by the steamship and other lines, mentioned in previous reports,
in carrying tlie boxes of tlie Smithsonian exchanges free of charge, has been

VOL. II.— 20 73

306 BULLETIN or THE

" This pai't of the system of Smithsonian operations has even'-
where received the comuiendatiou of those who have given it
their attention or have participated in its benefits. The Institu-
tion is now the principal agent of scientific and literary com-
munication between the old world and the new. . . , The
importance of such a system with reference to the scientific
character of our country, could scarcely be appreciated by those
who are not familiar with the results which How from an easy
and certain intercommunication of this kind. Many of the most
important contributions to science made in America have been
unheard of in Europe, or have been so little known, or received
so little attention, that they have been republished as new dis-
coveries or claimed as the product of European research."* It
would indeed be difficult to estimate rightly the benefit to science
in the encouragement of its cultivators ailorded by this fostering
service. Few Societies are able to incur much expense in the
distribution of their publications ; and hence their circulation is
necessarily very limited. The fructifying interchange of labors
and results, dependent on their own resources, would be ob-
structed by the recurring expenses and delays of customs inter-
ventions, and by unconscionable exactions : and indeed without
the Smithsonian mechanism, nine-tenths of the present scientific
exchanges would be at once suppressed. Let it be hoped that
so beneficent a system will not break down from the weight of
its own inevitable growth.

Astronomical Telegraphy. — Analogous in principle to the
system of exchange, is that adopted for the instantaneous trans-
Atlantic communication of discoveries of a special order. In the
year 1878, in the interests of astronomy (to which Heniy was ever
warmly devoted) he concluded " a very important arrangement
between the Smithsonian Institution and the Atlantic cable Com-
panies, by which is guaranteed the free transmission by telegraph
between Europe and America of accounts of astronomical discov-
eries which for the purpose of co-operative observation require
immediate announcement."t This admirable service to science,
so creditable to the intelligence and the liberality of the Atlantic
Telegraph Companies, emljraces direct reciprocal communication
between the Smithsonian Institution, and the foreign Observato-
ries of Greenwich, Paris, Berlin, Vienna, and Pulkova. During
the first year of its operation, four new planetoids were tele-

continuprl. anri ppreral otlier lines have been ad'led to ihe number in the
course of the year." (Smilhwnian Report for 1867, p. 39.) Notwithstand-
ing this unprecedented generosity, the exchange system has reached such
proportions as to reqnire for its maintenance one-fourth of the entire
income from tlie Smithsonian fund.

* Smithsoninn Eepo t 'or 18.'i3, p. 2.5, (of Senate ed.)

t Smithsonian Report for 1873, p. 32.

80

PHILOSOPHICAL SOCIETY OF WASHINGTON. 307

graphed from America, and seven telescopic comets from Europe
to this country.

" Altliougli the discovery of planets and comets will probably
be the principal subject of the cable telegrams, yet it is not in-
tended to restrict the transmission of intelligence solely to that
class of observation. Any remarkable solar phenomenon pre-
senting itself suddenly in Europe, observations of which may be
practicable in America several hours after the sun lias set to the
European observer, — the sudden outburst of some variable star
similar to that which appeared in Corona borealis in 18G6, — un-
expected showers of shooting-stars, etc., would be proper subjects
for transmission by cable.

" The announcement of this ai-rangement has called forth the
approbation of the astronomers of the world : and in regard to
it we may quote the following passage from the fifty-fourth annual
report of the Royal Astronomical Society of England : ' The
great value of this concession on the part of the Atlantic tele-
graph and other Companies, cannot be too highly prized, and
our science must certainly be the gainer by this disinterested act
of liberality. Already planets discovered in America have been
observed in Europe on the evening following the receipt of the
telegram, or within two or three days of their discovery ' "*

Official Correspondence. — A vast amount of individual work
having in view the diffusion of knowledge, has been performed
by the correspondence of the Institution ; which may be best
described in the language of an extract from one of the early
Reports. " There is one part of the Smithsonian operations that
attracts no public attention, though it is producing important
results in the way of diffusing knowledge, and is attended perhaps
with more laborthau any other part. I allude to the scientific
correspondence of the Institution. Scarcely a day passes in
which communications are not received from persons in different
parts of the country, containing accounts of discoveries, which
are referred to the Institution, or asking questions relative to
some branch of knowledge. The rule was early adopted to give
respectful attention to every letter received, and this has been
faithfully adhered to from the beginning up to the present
time. ." . . Requests are frequently made for lists of appa-
ratus, for information as to the best books for the study of special

* Smithsoman Report for 1873, p. 33. Hi 1876, a stellar outburst in the
"Swan' observed by Dr. Schmidt of Atliens, on the 24th of November,
was announced. Less brilliant than the similar outburst which occurred
in the northern "Crown" in May 18(36, it continued to decline through
the month of December, and at the close of the year, had dwindled from
the third to the eighth magnitude. This may possibly be the same " tem-
porary star" — seen in Cyqi^ns in 1600, and again in 1670: and having
therefore a period of variability of about 69 years.

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308 BULLETIN OF THE

subjects, for suggestions on the organization of local societies,
etc. Applications are also made for information by persons
al)road, relative to particular subjects respecting this country.
When an immediate reply cannot be given to a question, the
subject is referred by letter to some one of the Smithsonian co-
laborers to whose line of duty it pertains, and the answer is
transmitted to the inquirer, either under the name of the person
who gives the information, or under that of the Institution, ac-
cording to the circumstances of the case. . . . Many of
those communications are of such a character, that at first sight
it might seem best to treat them with silent neglect ; but the rule
has been adopted to state candidly and respectfully the objections
to such propositions, and to endeavor to convince their authors
that their ground is untenable. Though this course is in many
cases attended with no beneficial results, still it is the only one
which can be adopted with any hope of even partial good."*

The information given to scientific inquirers has been of an
exceedingly varied and highly valuable charocter, not unfre-
quently involving a large amount of research from special ex-
perts ; who have been accustomed cheerfully to bestow a degree of
attention on difficult questions thus presented, which would have
been accorded perhaps less ungrudgingly to others than to the
universally honored Smithsonian Director. As to the pretensions
and importunities of the unscientific, — such is the judgment pro-
nounced after a quarter of a century of laborious experience with
them :

" The most troublesome correspondents are persons of exten-
sive reading, and in some cases of considerable literary acquire-
ments, who in earlier life were not imbued with scientific methods,
but who not without a certain degree of mental power, imagine
that they have made great discoveries in the way of high gene-
ralizations. Their claims not being allowed, they rank them-
selves among the martyrs of science, against whom the scientific
schools and the envy of the world have arrayed themselves. In-
deed to such intensity does this feeling arise in certain persons,
that on their special subjects they are really monomaniacs,
although on others they may be not only entirely sane, but even
evince abilities of a high order. . . . Two persons of this class
have recently made a special journey to Washington, from dis-
tant parts of the country, to demand justice from the Institution
in the way of recognition of their claims to discoveries in science
of great importance to humanity ; and each of them has made
an appeal to his Representative in Congress to aid him in com-
pelling the Institution to acknowledge the merits of his specula-
tions. Providence vindicates in such cases the equality of its
justice in giving to such persons an undue share of self-esteem

* Smithsonian Report for 1853, pp. 22, 23, (of Senate ed.)

82

PHILOSOPHICAL SOCIETY OF WASHINGTON. 309

and an exaltation of confidence in themselves, which in a great
degree compensate for what they conceive to be the want of a
just appreciation of the public. Unless however they are men
of great benevolence of disposition, who can look with pity on
what they deem the ignorance and prejudice of leaders of science,
they are apt to indulge in a bitterness of denunciation which
might be injurious to the reputation of the Institution, were their
effects not neutralized by the extravagance of the assertions
themselves."*

To the projectors and propellers of Paine electric engines,
and Keely motors, eager for a marketable certificate from such
an authority, Henry would calmly reply : " We may say that
science has established the great fact — without the possibility of
doubt, that what is called power, or that which produces changes
in matter, cannot be created by man, but exists in nature in a
state of activity or in a condition of neutralization ; and further-
more that all the original forces connected with our globe, as a
general rule have assumed a state of permanent equilibrium, and
that the crust of the earth as a whole (with the exception of the
comparatively exceedingly small proportion, consisting of organic
matter such as coal, wood, etc.) is as it were a burnt slag, in-
capable of yielding power; and that all the motions and changes
on its surface are due to actions from celestial space, principally
from the sun. . . . All attempts to substitute electricity or mag-
netism for coal power must be unsuccessful, since these powers
tend to an equilibrium from which they can only be disturbed by
the application of another power, which is the equivalent of that
w^liich they can subsequently exhibit. They are however, with
chemical attraction, etc., of great importance as intermediate
agents in the application of the power of heat as derived from
combustion. Science does not indicate in the slightest degree,
the possibility of the discovery of a new primary power com-
parable with that of combustion as exhibited in the burning of
coal. Whatever unknown powers may exist in nature capable
of doing work, must be in a state of neutralization, otherwise
they would manifest themselves spontaneously ; and from this
state of neutralization or equilibrium, they can be released only
by the act'on of an extraneous power of equivalent energy ; and
we therefore do not hesitate to say that, all declarations of the
discovery of a new power which is to supersede the use of coal
as a motive-power, have their origin in ignorance or deception,
and frequently in both. A man of some ingenuity in combining
mechanical elements, and having some indefinite scientific know-
ledge, imagines it possible to obtain a certain result by a given
combination of principles, and by long brooding over this sub-

* Smithsonian R<port for 1875, pp. 37, 38.^
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310 BULLETIN OF THE

ject previous to experiment, at length convinces himself of the
certainty of the anticipated result. Having thus deceived him-
self by his sophisms, be calls upon his neighbors to accept his
conclusions as verified truths; and soon acquires the notoriety
of having made a discovery which is to change the civilization of
the world. The shadowy reputation which he has thus acquired,
is too gratifying to his vanity to be at once relinquished by the
announcement of his self-deception ; and in preference he ap-
])lies his ingenuity in devising means by which to continue the
deception of his friends and supporters, long after he himself has
been convinced of the fallacy of his first assumptions. In this
way what was commenced in folly, generally ends in fraud."*

In looking back upon the struggles, conflicts, and obstructions
of the past, it really seems quite marvellous that so much should
have been accomplished, with so limited expenditure. These
large results are partly due to the admirable method of the Sec-
retary, his clear presage of effects, and his high power of sys-
tematic distribution and appliance; partly to the intelligent zeal
and sympathetic energy of the able assistants whom he had asso-
ciated with him almost from the organization of the institution ;
and partly to the personal magic of the man, — to the surprising
amount of voluntary co-operation he was able to call forth in
almost every direction, by the sheer force of his own earnest in-
dustry, and the contagious influence of his own devotion to the
cause of scientific advancement.

An unwarranted Arraignment. — In 1855, while still with
quiet determination maintaining the fundamental purpose of his
Smithsonian administration against the pressure and opposition
of powerful influences, (the discussion having been even carried
to the halls of Congress,) Henry was made the subject of a
most wanton and ungrateful public attack, in a pamphlet by
Prof Morse of Telegraph fame, impugning not only his scien-
tific reputation, but for the first time — the truthfulness of his
testimony given in certain telegraph suits some half a dozen
years previously, in reluctant obedience to legal summons. f
This testimony thus exacted, of course failed to sustain the
complainant's exorbitant claims to the absolute invention and
ownership of all possible forms of the electro-magnetic telegraph,

* Smithsonian Report for 1875, pp. 39, 40.

t The Hon. S. P. Chase, while Governor rf Oh'o, fsub.sequently Chief
Justice of the Supreme Court of the United States,) in a letter dated
Columbus, Nov. 26, 1856, after reciting his professional connection witli
the litigations of 1849, says : " I remember very well that you were un-
willing to be involved in the controversy^ even as a witness, and that you
only submitted to be examined in compliance with the requirements of
law. Not one of your statements was volunteered."

84

PHILOSOPHICAL SOCIETY OF WASHINGTON. 311

and correspondingly failed to satisfy the cupidity of the actual
l)rosecutors : and in this remarkable accusation first published
iu 1855, could readily be discerned the mercenary inspiration of
interested capitalists and assignees — anxious only to stretch the
monopoly to its extremest grasp. To Prof. Morse himself in
his early efforts, Henry had generously rendered every encourage-
ment and assistance ; and in his later successes had as freely
extended his congratulations and his testimonials of the prac-
tical merits of his invention.*

To descend to a personal controversy with Mr. Morse, was
utterly repugnant to Henry's feelings : to permit his serious
impeachment to stand untraversed, appeared scarcely less objec-
tionable. With a calm and self-respecting dignity, Henry simply
presented the published arraignment to the Board of Regents, for
their consideration and action, with a communication dated
March 16, 1857, in the following terms:

" Gentlemen : In the discharge of the important and responsible
duties which devolve upon me as Secretary of the Smithsonian
Institution, I have found myself exposed like other men in pulilic
positions to unprovoked attack and injurious misrepresentation.
Many instances of this it may be remembered, occurred about two
years ago. during the discussions relative to the organic policy
of the Institution : but though very unjust, they were suffered to
pass unnoticed ; and generally made 1 presume no lasting impres-
sion on the public mind. During the same controversy however,
there was one attack made upon me of such a nature, so elaborately
prepared and widely circulated by my opponents, that though I
have not yet publicly noticed it, I have from the first thought it
my duty not to allow it to go unanswered. I allude to an article
from the pen of Prof S. F. B. Morse, the celebrated inventor of the
American electro-magnetic telegraph. In this, not my scientific
reputation merely, but my moral character was pointedly assailed :
indeed nothing less was attempted than to prove that in the tes-
timony which I had given in a case where I was at most but a
reluctant witness, I had consciously and wilfully deviated from
the truth, and this too from unworthy and dishonorable motives.
Such a charge, coming from such a quarter, appeared to me then
as it appears now, of too grave a character and too serious a
consequence, to be withheld from the notice of the Board of

* " It was my wish in every statement to render Mr. Morse full and
scrupulous justice. While I was constrained therefore to state that he
had made no disi-oveiies in science, I distinctly declared that he was
entitled to the merit of combining and applying the discoveries of others
iu the invention of the best practical form of the magnetic telegraph. My
testimony tended to establish the fact that though not entitled to the
exclusive use of the electro-magnet for telegrnphio purposes, he was en-
titled to his particular machine, register, aipiiabet, etc. Tliis however
did not meet the full requirements of Air. Morse's compiehensive
claim."

85

312 BULLETIN OF THE

Regents : . . . and I now embrace the first opportunity of
bringing- the subject official]}' to your notice, and asking from you
an investigation into the justice of the charges alleged against
me. And this I do most earnestly, with the desire that when we
shall all have passed from this stage of being, no imputation of
having attempted to evade in silence so grave a charge shall rest
on me, — nor on you, of having continued to devolve upon mc
duties of the highest responsibility, after that was known to some
of you individually, which if true — should render me entirely
unworthy of your confidence. Duty to the Board of Regents, as
well as regard to ray own memory, to my family, and to the truth
of history, demands that I should lay this matter before you, and
place in your hands the documents necessary to establish the
veracity of my testimony so falsely impeached, and the integrity
of my motives so wantonly assailed."*

Professor Felton, President of Harvard University, Chairman
of the select Committee appointed by the Regents to investigate
the charge, after a careful examination of all the documentary
evidence, submitted a full report, from which it is only necessary
to make the following extracts with reference to the Morse
pamphlet : "The first thing which strikes the reader of this article
is that its title is a misnomer. f It is simply an assault upon
Professor Henry; an attempt to disparage his character; to
deprive him of his honors as a scientific discoverer ; to impeach his
credibility as a witness and his integrity as a man. It is a dis-
ingenuous piece of sophistical argument, such as an unscrupulous
advocate might employ to pervert the truth, misrepresent the
facts, and misinterpret the language in which the facts belonging
to the other side of the case are stated. . . . Your committee
come unhesitatingly to the conclusion that Mr. Morse has failed to
substantiate any one of the charges he has made against Profes-
sor Henry, although the burden of proof lay upon him ; and
that all the evidence — including the unbiased admissions of Mr.
Morse himself — is on the other side. Mr. Morse's charges not
only remain unproved, but they are positively disproved." And
the committee submitted resolutions of condemnation on the one
side, and of respect and confidence on the other, which were
unanimously adopted by the Regents, and made a part of the
permanent record. J

* Smithsonian Report for 1857, pp. 85, S').

f " A Defence against the injnrions rlerluctionf5 drawn from the Depo-
.cition of Professor .Joseph Henry, by Samuel F. B. Morse."

X Smithsonian Report for 1857, pp. 89-9S. When Prof. Morse in his
letter to Prof. Sears C. Walker, dated Washington, Jan. 1st, 1848, wrote
thns : " To Prof. Henry is unquestionahly due the honor of the discovery
of a fact in science which proves the practicahility of exciting magnetism
through a long coil or at a distance, eitiier to deflect a needle or mag-
netize soft iron ;" and wiien ajrain some six years later, the same Prof.
Morse in his pamphlet dated Locust Grove, New York, December, 1S53,

86

PHILOSOPHICAL SOCIETY OF WASHINGTON. 313

Scientific Observations. — One of the objects very dear to
Henry's heart, was the establishment of a physical observatory
(with a i)hysical laboratory in connection) for the systematic
observation and record of important points in celestial and
terrestrial physics. For the proper maintenance of such an
establishment, he thought an income as large as that of the
Smithson fund, would not be too large: and on two different
occasions he endeavored to enlist the interest of wealthy and
public-spirited citizens in such an enterprise. One of these
was Mr. McCormick of Virginia ; and a letter on the subject
was afterward printed (without its address) in the Report for
1870:* The other was Mr. Lick of California: who after some
hesitation, decided in favor of an astronomical observatory.
Another allied object of great interest to Henry — and one re-
quiring as large an endowment — was a well-equipped chemical
laboratory, in which — under judicious restrictions — those really
engaged in original researches, should have liberal facilities of
appliances and needed materials, furnished them. He considered
that an important part of the work to be accomplished by a
physical and chemical laboratory, would be the determination
and tabulation of " The Constants of Nature and Art" with a
much wider range of subject, and on a scale of much greater
completeness and accuracy, than had heretofore been attempted :
and thus might be realized the great work or works of reference,
suggested by Babbage as a scientific desideratum.-f Had the
Smithsonian fund been twice as large as it is, both these great
enterprises for the increase of knowledge, would undoubtedly
have been successfully inaugurated by Henry.

Loss by Fire. — Early in the year 1865, (on the 24th day of
January,) the central portion of the Smithsonian Building suf-
fered from a disastrous fire, the effects of which were aggravated
by the extreme severity of the winter cold, which greatly obstructed
the efficiency of the engines brought into action. | " The progress
of the fire was so rapid, that but few of the contents of the upper
rooms could be removed before the roof fell in. The conflagration

wrote: "I shall show that I am not indehterl to hitu for any discovery in
science, bearinsf on tlie Telegraph:" (p. 9,) — it may be confidently
assumed fron his known but singular unfamiliarity with scientific litera-
ture, that equally in either case he but echoed the promptings of others,
and equally in either case in entire ignorance of tlie real facts. To his
dying day, he probably sincerely failed to apprehend the nature of his
indebtedness to Henry.

* Smithsonian Re/wrt for 1870, pp. 141-144.

f Smithsonian Report for 1856, pp. 289-302.

X The accident resulted from the carelessness of some workmen in the
upper picture gallery, who in temporarily setting up a stove, inseited the
]iipe through a wall-lining into a furring space (supposing it a flue), but
which conducted directly under the rafters of the roof.

87

314 BULLETIN OF THE

was only stayed by the incombustible materials of the main build-
ing :" the flooring of the upper story, forming an iron and brick
vaulting over the lower or principal story. Neither wing of the
building was reached by the fire ; and the valuable Library (not
then transferred to the Capitol), and the Museum, fortunately
escaped without injury. The Stanley collection of Indian por-
traits, comprising about 200 paintings, and estimated as worth
20,000 dollars, was entirely destroyed. A fine full-sized copy in
Carrara marble, b}' John Gott, of the antique statue known as
" The Dying Gladiator," was crumbled into a formless mass of
stone.

The Secretary's ofiSce unfortunately fell within the range of
the flames. " The most irreparable loss was that of the records,
consisting of the official, scientific, and miscellaneous corres-
pondence ; embracing 35,000 pages of copied letters which had
been sent, (at least 30,000 of which were the composition of the
Secretary,) and 50,000 pages of letters received by the Institu-
tion ; the receipts for publications and specimens; reports on
various subjects which have been referred to the Institution ;
the records of experiments instituted by the Secretary for the
Government; four manuscripts of original investigations, [me-
moirs by collaborators,] which had been adopted by the Insti-
tution for publication ; a large number of papers and scientific
notes of the Secretary ; a series of diaries, memorandum and
account books."* This truly " irreparable loss" of the original
notes of many series of experiments by Henry, of varied cha-
racter, running back for thirty years, kept for the purpose of
reduction and discussion, or further extension (as leisure might
permit) and of which but few had been published even by re-
sults,— was borne by their author with his characteristic equa-
nimity ; and was very rarely alluded to by him, unless when in
answer to inquiries respecting particular points of his researches,
he was compelled to excuse the absence of precise data.

The Lecture Room — a model of its class — entirely burned out
by the fire, was not reconstructed : but the space it occupied on
the upper floor, was with the adjacent rooms (used as the appa-
ratus room, and the art gallery) thrown into one large hall, 200
feet long, — at present occupied as the ethnological museum.
Advantage was taken of the hazard demonstrated by the fire, to
induce Congress in the following year to transfer the custody
of the Smithsonian collection of scientific works to the National
Library: and the propriety of this change was thus defended.
" The east wing of the Smithsonian building, in which the books
were deposited is not fire-proof, and is liable to destruction by
accident or the torch of the incendiary, while the rooms of the
Capitol are of incombustible materials. This wing was more-

* Sm'thsonian Rpport for 1SG5, p. 18.
88

PHILOSOPHICAL SOCIETY OF WASHINGTON. 315

over filled to overflowing; and a more extended and secure
depository could not be obtained, except by another large draught
on the accumulated funds intended to form part of the pei maueut
capital.'"*

Secol^d Visit to Europe.— Ki a meeting of the Board of Re-
gents, held February 3rd, 1870, "General Delafield in behalf of
the Executive Committee, stated that they deemed it highly
important for the interests of the Institution in the promotion
of science, and due to the Secretary for his long and devoted
services, that he should visit Europe to consult with the savans
and societies of Great Britain and the continent ; and he therefore
hoped that a leave of absence would be granted to Professor
Henry for several months, and an allowance be made for his
expenses. On motion of Dr. Maclean it was unanimously Re-
solved, That Professor Henry, Secretary of the Institution, be
authorized to visit Europe in behalf of the interests of the Smith-
sonian Institution, and that he be granted from three to six
months leave of absence, and two thousand dollars for travelling
expenses for this purpose."f

It is not necessary here to recount the particulars of this
second visit of Henry to Europe, more fully than in the brief
account given by him in his annual Report. "Before closing
this report, it is proper that I should refer to a resolution
adopted by your honorable Board at its last session, granting
me leave of absence to visit Europe to confer with savans and
societies relative to the Institution, and making provision for
the payment of my expenses. The presentation of this propo-
sition was entirely without my knowledge, but I need scarcely
say that its unanimous adoption was highly gratifying to my
feelings; and that I availed myself of the privilege it offered
with a grateful appreciation of the kindness intended. I sailed
from New York on the 1st of June, returning after an absence
of four and a half months, much improved in health, and with
impressions as to science and education in the Old World, which
may be of value in directing the affairs of the Institution. Al-
though limited as to time, and my plans interfered with somewhat
by the war, I visited England, Ireland, Scotland, Belgium, parts
of Germany and France. But deferring for the present an ac-
count of my travels, and the observations connected with them,
I will merely state that as your representative, I was everywhere
kindly received, and was highly gratified with the commenda-
tions bestowed on the character and operations of the Institutiou
intrusted to your care. "J

* Smithsonian Rpport for 186fi, p. 14.
t Smithftonian Report for 1 869, p. 89.
X Smithsonian Ecporl for 1870, p. 45.

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316 BULLETIN OF THE

Service on the Light-house Board. — While the whole high
bent of Henry's mind was rather toward abstract than utilitarian
research, there was no well devised system of practical benefit
for man, that did not command his earnest sympathy or enlist
his active co-operation : — no labor in such co-operation from
which he shrank, if he felt that without the sacrifice of other
duties, he could make such labor useful. On the establishment
of the Light-house Board, in 1852, Henry was appointed as one
of its members ; and although his valuable time was already
fully occupied, he consented to serve on the Board, in the hope
of aiding to benefit the interests of navigation. To the require-
ments of his new position, he brought his accustomed energ}^
skill, and eminently practical judgment ; and soon made his
influence felt throughout the Light-house service.

"When the steadily advancing cost of whale oil made it neces-
sary to seek for some more economical illuminant, he attacked
the problem with bis habit of scientific method. Colza oil or
rape-seed oil had been used in France with some success ; and
efforts were made to introduce its culture and production in this
country. Lard-oil had been tested by Professor J. H. Alexander
of Baltimore, and pronounced by him of very inferior value as an
illuminant. For accuracy of determination, Henry caused to be
prepared at the Light-house Depot on Staten Island, a long
dark fire-proof chamber, and had it painted black on all its
interior surfaces for the purpose of photometric observations.
In ordinary lamps, the colza oil was found to be nearly equal to
whale oil in illuminating power, and lard-oil inferior to it. Pe-
troleum or mineral oil was also tried ; but its quality was at
that time too variable, and its use was found to be too dangerous.
Experiment showed that lard-oil had a greater specific gravity
than sperm oil, a less capillarity or ascensional attraction in a
wick, and a less perfect fluidity. The conditions were varied;
and it was found that with elevation of temperature, the fluidity,
and the capillarity, of the lard-oil increased more rapidly than
those of the sperm oil, until at about 250^ F. the former sur-
passed the latter in these qualities. With these results, it became
important to compare the oils in large lamps, such as were actually
required for the lanterns of light-houses. The heat evolved by
the large sized Argand burners, would seem peculiarly to favor
the lard-oil : a few trials, with a proper adaptation of the lamps,
established its supremacy; and conclusively demonstrated — con-
trary to all the laboratory trials of former experimenters, that for
the purpose desired, this contemned article was for equal quan-
tities a more brilliant illuminant than mineral kerosene-oil, or
vegetable colza-oil, or animal sperm-oil, while its market price
was only about one-fourth that of the latter. Against all the
opposition of interested dealers, and prejudiced keepers, the lard-

90

PHILOSOPHICAL SOCIETY OF WASHINGTON. 317

oil was at once introduced into actual use in the years 1865 and
1866, in all the light-houses of the United States; with an
economy of at least one dollar on every gallon of the hundred
thousand in annual use ; that is of 100,000 dollars per annum.

During the progress of these useful labors, no less important
investigations were commenced, on tiie most efficient forms of
apparatus for acoustic signalling, as the substitutes for light
signals during the prevalence of sea-board fogs. " Among the
impediments to navigation, none are perhaps more to be dreaded
than those which arise from fogs. . . . The only means at
present known for obviating the difficulty, is that of employing
powerful sounding instruments which may be heard at a suffi-
cient distance through the fog, to give timely v/arning of impend-
ing danger."*

Gun signals were early abandoned, as inefficient, dangerous,
and expensive : inefficient, because of both " the length of the
intervals between the successive explosions, and the brief dura-
tion of the sound, which renders it difficult to determine with
accuracy its direction." Innumerable projects eagerly pressed
Upon the Board by visionary inventors (some of them being
rattles, gongs, or organ pipes operated by manual cranks, many
of them being varieties of automatic horn or whistle operated
by the winds or the waves) were impartially tested, and uni-
formly rejected as wholly insufficient: very few of their projec-
tors having the slightest practical idea of the requirements of
the service. Experiments on steam-whistles of large size and
on horns with vibrating steel tongues or reeds, sounded by steam-
power, or by hot-air engines, varied and continued for several
years under wide changes of conditions, finally determined their
most efficient size and character t

In 1867, comparative trials were made at Sandy Hook (on
the Jersey shore, at the entrance to Raritan Bay, and to New
York Bay,) with three powerful instruments; a large steam
whistle whose cup was 8 inches in diameter, and made adjust-
able in pitch ; a large reed trumpet 17 feet long and 38 inches
in diameter at its flaring mouth, whose steel tongue was 10 inches
long, 2| inches wide, and half an inch thick at its smaller vibrat-
ing end, and was blown by a hot air engine ; and lastly a large

* Ri'port of L. H. Board for 1874, p. 8.3.

f Au enterprising inventor had secured a patent for a metallic com-
pound or alloy for steam-whistles, especially adapted to increase greatly
tlieir power a-< fog signals. In vain was lie assured that his "improve-
ment" was a fallacy ; that the cylindrical cup of the whistle was not a
bell, but only a resonant chamber; and that its material was compara-
tively unimportant. He was only with dilficulty convinced, when Henry
had his whistle formally tested, with a stout cord wound tightly around
its cylindrical surface : when its tone under steam e?!cape was proved to
be as full, as loud, and as penetrating, as with the cord removfd.

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BIS BULLETIN OF THE

siren horn operated by steam at different pressures, the aerial
vibration being produced by the intennittence of a revolving
grating or disk valve in the small end of the horn, driven at high
velocities by the steam engine, and its pitch regulated by the
adjustable speed of the revolving disk. The trumpet or fog-horn
was provided with a series of replaceable steel tongues of diffe-
rent sizes, and the siren was driven at five different pitches of
from 250 to VOO impulses per second, and at steam pressures
varying from 100 pounds to 20 pounds per square inch. For
the purpose of accurate estimation, within short distances, a
phonometer or "artificial ear" was employed, having at its
smaller upturned end a horizontal drum of stretclied membrane,
sprinkled with sand, after the plan devised by Sondhauss. Trum-
pets of the same size, were made of different materials, as of
brass, iron, and wood ; but these differences were found to exer-
cise little or no influence on the intensity or penetration of the
sound. Trumpets were also made of different shapes, straight
and curved, and square as well as round, with equal lengths and
equal areas of cross section ; from whose trials it appeared that
the conical form gave nearly double the distance of action on the
sand of the "artificial ear," that was given by the pyramidal
form. Such investigations — varied and long-continued, serve to
shovp' the conscientious earnestness with which Henry sought to
give the highest efficiency to the expedients available for the
protection of life and property along our extended sea-coast.

The steam-whistle was found to be less powerful than the
trumpet, with the same expenditures of fuel. Steam whistles
were afterwards tried of 10 inches, 12 inches, and 18 inches in
diameter. The largest size was not found to give results pro-
portioned to its increased consumption ; and the 10 or 12 inch
size was regarded as practically the most efficient. The siren
was found to be the most powerful and penetrating of the instru-
ments tested, as it admitted more advantageously the application
of a higher steam expenditure. The best result with this instru-
ment was attained with a pressure of from 60 to 80 pound's, and
at a pitch between 350 and 400 vibrations per second. Under
favorable conditions, this instrument frequently made itself heard
at a distance of fifteen and twenty miles. Henry's large expe-
rience with the occasional aerial impediments to sound propaga-
tion,* and his strong sense of the vital importance of having
fog-signals recognized at a distance, under the most adverse con-
ditions, led him to favor the introduction of the most powerful
sounders attainable, without absolutely limiting the decision to
their relative economy. Hence he was the first to devise improve-
ments in the siren, and to press its adoption at important or

* An abstract of his elaborate and invaluable researches on somp ab-
normal phenomena of Round — the crowning labor of his life, must be re-
served for a concluding section.

92

PHILOSOPHICAL SOCIETY OF WASHINGTON. 319

dangerous stations, notwithstanding its higher consumption of
steam or heat power.*

Partly under the stimulus given to the sale of lard-oil by the
striking proofs of its excellence as an illaminant under favor-
able conditions, furnished by Henry, this article slowly advanced
in price ; though probably not to an extent of more than a fourth
part additional cost. Henry's energies again were called into
requisition to devise a remedy. Neither gas, nor electricity, the
favorite means of numerous projectors and advisers, appeared
justified, on the score of economy.f A new series of elaborate
experiments was undertaken to determine whether mineral oil
(so abundant as to be easily procurable at one-third the cost of
lard oil) could not be made available. The great improvements
introduced into its preparation in later years by high distillation,
seemed to justify the attempt. Not only was a laborious inquiry
into the best conditions of combustion, by precise photometric
measurement required, but for the security of the service, equally
laborious examinations into the best practicable methods of test-
ing, of handling, and of storing this material.| To secure a

* Major G. H. Elliott, commissioiied by the U. S. Light-house Board to
make a tonr of inspection of European Light-liouse establishments in
1873, in his Report published by the Senate in 1874. says of the British
and French systems, " I saw many details of construction and administra-
tion which we can adopt to advantage, while there are many in which
we excel. Our shore fog-signals particularly, are vastly superior both in
number and power." (Rejiort on European Light-houses, p. 12.) "To
the careful and laborious investigations and experiments of the distin-
guished Chairman of the Light-house Board, prolonged through a series
of years, and prosecuted under a great variety of conditions, is largely
to be attributed the acknowledged superiority of our fog-signal service."
{Journal of Frank/ in Institute, Jan. 1876, vol. Ixxi. p. 43.)

f Report of L. H. Board for 1874, p. 11. No agency (for whatever
purpose) has proved so enticing to the half- in formed as electricity. For
years past scarcely a month has elapsed without some new form of patent
electric-light, or some marvellous application of electric-lights, being
pertinaciously urged by sanguine "reformers" upon the Light-house
Board for adoption ; some of these ideal schemes being the mounting of
electric-lights on buoys, or on the masts of light-ships, or their suspen-
sion from moored balloons. Many eminently original minds have earn-
estly desired to obtain contracts for supplying all the Light-houses with
oxy-hydrogeu Mme lights. In a fog, the most powerful electric-light is as
useless as the cheapest kerosene lamp.

X "It has been established that the ordinary fire-test is insufficient as
usually applied, and that an explosive mixture may be formed by con-
fining the vapors given off at a temperature in some cases twenty degrees
lower than that certified to by the public inspector. That this inquiry is
of great practical importance to the Light-house system, must be evident
when we reflect that means must be devised for testing the oil offered for
acceptance in accordance with contracts ; for storing it : for transporting
it to light-house stations ; for preserving it in butts at the stations ; and
for the instruction of the keepers in its daily use." {Report L. U. B.
1877, p. 5.)

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320 BULLETIN OF THE

proper oxygenation in burning, a modification of the lamp was
required. "It was soon apparent that the use of mineral oil
would necessitate a change of lamps, and attention is now
directed to the perfection of one which will produce the best
results from this illuminant. It is thought that the lamps now
used with lard-oil can be converted at no great expense and
successfully used with mineral oil. Our experiments have shown
that this oil can be more readil}- used in the smaller lamps ; and
it is proposed as soon as suitable ones can be prepared, to put it
into use at such stations of the fifth and sixth order, as may be
thought expedient ; when if it be found satisfactory, an attempt
w\\\ be made to substitute it for lard-oil in lamps of the higher
orders."* " This change is proposed entirely with reference to
economy ; for it has been found by repeated experiment, that
while a somewhat superior light may be obtained from a small
lamp charged with kerosene, a larger lamp charged with lard-oil
affords the greater illuminating power. So great is this differ-
ence in lamps of the first order with five wicks, that the rates of
light from kerosene and lard, are as three to four respectively.
Since the safety of the keeper and the continuity of the light are
essential elements in the choice of an illuminant, a thorough
acquaintance with the nature of the substance is essentially
necessary. With a view therefore to the introduction of kerosene,
a series of experiments have been made during the last two
years on the different varieties of this material found in the
market."!

In 1871, on the resignation of Admiral Shubrick, Ilenry was
chosen as the Chairman of the Light-house Board; and his
energetic labors in behalf of the service, fully vindicated the
wisdom of the choice. Punctual in his attendance on the weekly
meetings of the Board, he inspired others with a portion of his own
zealous devotion. Nor did he fail to urge upon the Government
the constant need and responsibility of maintaining an efficient
establishment. He emphatically declared that " the character
of the aids which any nation furnishes the mariner in approaching
and leaving its shores, marks in a conspicuous degree its advance-
ment in civilization. Whatever tends to facilitate navigation or
to lessen its dangers, serves to increase commerce ; and hence is
of importance not only to the dwellers on the seaboard, but to
the inhabitants of every part of the country. . . . Therefore
it is of the first importance that the signals, whether of light or
sound, which indicate the direction of the course, and the beacons
which mark the channel, shall be of the most improved character,
and that they be under the charge of intelligent, efficient, and

* Report L. H. Board, 1875, p. 6.

t Report L. U. Board, 1877, p. 4.

94

PHILOSOPHICAL SOCIETY OF WASHINGTON. 321

trustworthy attendants."* And rising to a higher argument, he
pointed out tliat " it is not alone in its economical aspect that a
liglit-house system is to be regarded : it is a life preserving es-
taljlishment founded on the principles of Christian benevolence,
of which none can so well appreciate the importance as he who
after having been exposed to the perils of the ocean — it may be
lor uiontlis — finds himself approaching in the darkness of night
a lee shore. But it is not enough to erect towers, and establish
other signals : they must be maintained in an efficient state with
uninterrupted constancy."!

A formal report made to the Hon. Secretary of the Treasury
by the Naval Secretary of the Light-house Board, dated May
21st, 1878, (very shortly after Henry's death,) simply detailing
for information, the character of his gratuitous services to the
Light-house establishment during a quarter of a century, (and
not intended for the public,) takes the inevitable form of eulogy.
A portion of it is here quoted.

"As chairman of this committee. Professor Henry acted as the
scientific adviser of the Board. But in addition it was his duty
to conduct the experiments made by the Board, not only in the
matter of original investigation and testing of the material used,
but in examining and reporting on the models, plans, and theories
presented by others to the Board. The value of the services he
rendered in this position is simply inestimable. He prepared
the formula for testing our oils ; he conducted the series of ex-
periments resulting in the substitution of lard-oil for sperm oil,
which effected an immense saving in cost ; and he also conducted
the experiments which have resulted in making it possible to
substitute mineral oil for lard-oil, when another economy will be
made. His original investigation into the laws of sound have
resulted in giving us a fog-signal service conceded to be the best
in the world. His examinations into the action of electricity,
has enabled the Board to almost completely protect its stations
from the effect of lightning. The result of his patient, con-
tinuous, practical experimentation is visible everywhere in the

* Report of L. H. Board, 1873, pp. 3, 4. The coast line of the United
States is far more extended than that of any other nation on tlie globe.
"The magnitude of the Liglit-house system of the United States may he
inferred from tlie following facts: from tlie St. Croix River on the bound-
ary of Maine, to the mouth of the Rio Grande in the Gulf of Mexico, in-
cludes a distance of over 5,0(.iO miles ; on the Pacific coast, a length of
about 1,500 miles ; on the great northern Lakes, about 3,000 miles ; and on
inland rivers about 700 miles ; making a total of more than 10,000 miles.
Nearly every square foot of the margin of the sea throughout the whole
extent of 5,000 miles along the Atlantic and Gulf coast is more or less
illuminated by Light-house rays ; the mariner rarely losing sight of one
light until he has gained another." (p. 4, of same Report. J

t Report L. H. B. 1874. p. 5.

VOL. II.— 21 95

322 BULLETIN OF THE

service. No subject was too vast for him to undertake ; none
too small for him to overlook. And while he has brought into
the establishment so many practical applications of science, he
has done almost as much service by keeping out what presented
by others seemed plausible, but which on examination proved
impracticable.

" Every theory, plan, or machine, which was pressed on the
Board, as for the interests of commerce and navigation, was re-
ferred to the committee on experiments, when it was examined
by its Chairman, and was formally reported upon. If it had no
practical value, the report on record simply stated the inexpe-
diency of its adoption : but the Professor often verbally pointed
out to the presenter its fallacy ; and sent him away — if not
satisfied — at least feeling that he had been well treated. He
thus prevented not only the adoption of impracticable plans, but
avoided the enmity of their inventors.

" Professor Henry made many valuable reports, containing the
results of his elaborate experiments into matters which were for-
mally referred to him, which are spread on the records of the
Board ; and the reports were drawn in such form that his sug-
gestions were capable of and received practical application. But
in addition to this, he was constantly extending his scientific re-
searches for the benefit of the service in all directions. His
summer vacations were as a rule passed in experimentation at
the laboratory of the Establishment at Staten Island, on its
steamers, or at its light-stations, pushing his inquiries to their
last results. To experimentation in the interests of this service.
Professor Henry seemed to give his whole heart. It appeared
as if he never lost sight of the needs of the Establishment, and
as if he never neglected an opportunity to advance its interests.
In addition to his other duties. Professor Henry presided as
Chairman of the Light-house Board for the last seven years at
its weekly meetings, when he did much to infuse into the different
members of the Board, his own spirit of labor for, and devotion
to its interests."*

Services to the National Government. — The value of Henry's
services to the various Executive Departments of our Govern-
ment, faithfully and unostentatiously performed through a long
series of years and a succession of Presidential Administrations,
cannot be estimated, as its history can never be written. What-
ever material for it existed in the form of abstracts of inquiries,
trials, and reports, prior to 1865, unfortunately perished in the

* Executive Documents, No. 94, Forty-fifth Congrei?s, 2d Session, Senate,
pp. 2, 3. It is gratifying to know that on the presentation of his report
and recommendation to Congress, by the high-minded Secretary of the
Treasury, a moderate appropriation in slight recognition of Henry's " ines-
timable" services was at once passed for the benefit of his bereaved family.

96

PHILOSOPHICAL SOCIETY OF WASHINGTON. 323

fire of that year. Whenever in any important case a scientific
adviser could be useful to the proper conduct of a Bureau,
Henry's reputation generally pointed hiin out as the most suit-
able expert and arbiter. On the outbreak of the great civil war,
the number of such references was naturally very considerably
increased. The Departments of War, of the Navy, and of the
Treasury, were besieged by projectors with every imaginable and
impossible scheme for saving the country, and demolishing the
enemy. Torpedo balloons, electric-light balloons, wonderful com-
pounds destined to supersede gunpowder, and revolutionize the
art of war; cheap methods for the manufacture of Government
bonds and paper-money, multitudinous expedients for the pre-
vention of counterfeiting, by devices in the engraving, by secret
markings, by anti-photographic inks, by peculiar textures of
paper, — applicable to coupons, to circulating notes, to revenue
stamps, — each warranted to be infallible, — such were among the
agencies by which patriotic patentees and adroit adventurers
were willing to serve their country and to reap their reward by
the moderate royalty or percentage due to the magnificence of
the public benefit. Such were among the unenviable tasks of
examination and adjudication accepted by Henry, only from an
intrepid sense of duty.

" The course which has been pursued of rendering the Gov-
ernment in its late trials, every aid which could be supplied by
scientific research, has been warmly approved. As most persons
are probably entirely ignorant of the services really rendered to
the Government by the Institution, I may here state the fact that
a large share of my time, (all indeed which could be spared from
official duties,) has been devoted for the last four years to inves-
tigations required by the public exigencies. Within this period,
several hundred reports, requiring many experiments, and per-
taining either to proposals purporting to be of high national im-
portance, or relating to the quality of the multifarious articles
offered in fulfillment of legal contracts, have been rendered. The
opinions advanced in many of these reports, not only cost much
valuable time, but also involved grave responsibilities. While
on the one hand the rejection of a proposition would be in con-
travention to the high importance claimed for it by its author, on
the other the approval of it would perhaps incur the risk of the
fruitless expenditures of a large amount of public money. It is
not necessary, I trust, to say that the labor thus rendered was
entirely gratuitous, or that in the judgment pronounced in any
case, no regard was paid to the interested solicitations or per-
sonal influence of the parties concerned : on the contrary it has
in some instances resulted from the examination of materials sold
to the Government, that attempted fraud has been exposed, and
the baffled speculator received his due reward in condemnation
and punishment. These facts it is thought will be deemed a

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sufiBcient answer to those who have seemed disposed to reproach
the Institution with the want of a more popular demonstration
— but of a really far less useful or efficient aid in the support of
the Government."''

In the performance of these troublesome and often disagree-
able labors, conducted with the single aim necessitated by all his
scientific habits and instincts, it of course resulted that a great
majority of his judgments and recommendations were decidedly
adverse to the hopes and wishes of the aspirants to fame and
fortune. Having once satisfied himself of the frivolity or the
chicanery of an article or project, his decision was inflexible ;
and although importunate appeals to the Department Secretary,
abetted by a prostituted political or other inflaence, in one or
two instances succeeded in fastening for a time upon the public
Treasury a worthless or a noxious leech, the vast number of
such, excluded from experimental imbibitions by Henry's critical
supervision, must have been a protection to the public interests
quite beyond the reach of estimation : while the supplies of honest
contractors awarded their just commendation, and the rare pro-
posals of real merit favorably reported upon, which from a hasty
survey might have been confounded and overlaid with the mass
of untried puerilities, no less served to strengthen and assist the
Government during its years of greatest trial, need, and exhaus-
tion.

From the outset of the unnatural sectional revolt, fully appre-
ciating the vastness of the interests, the sacrifices, and the dan-
gers involved, Henry contemplated the crisis — not with despond-
ency, but with a profound sorrow and solicitude. While his
sympathies and his hopes were all for the preservation of the
national integrity of jurisdiction, he was little given to public
exhibitions of his feelings. Undemonstrative — less from tem-
perament than from the deliberate and habitual subjection of
emotional expression to reason, during those times of feverish
excitement apprehension and circumspection necessarily attend-
ant on the prevalence of a gigantic rebellion (unparalleled in
incentive, in temper, and in magnitude) many of whose leaders
had been among his personal friends, he was not unnaturally
looked upon by many as lukewarm in his patriotism, if not dis-
loyal in his citizenship. To the occasional innuendoes of the
press, he deigned no answers : he was the last man to accord
compliance with the urgency of a popular clamor. And yet
during the entire period of the Southern Insurrection, he was
the personal and trusted friend of President Lincoln. t

* Smithsonian Report for 1864, p. 15.

f Early in the war (in the autumn of 1861,) a callpr at the Presidential
Mansion very anxious to see the Chief Magistrate of the nation, was in-
formed that he could not tlien be seen, being engaged in an important pri-
vate consultation. The caller not to be repulsed, wrote on a piece of paper

PHILOSOPHICAL SOCIETY OF WASHINGTON. 325

CONTRIBUTIONS TO SCIENCE AT WASHINGTON.

In addition to what may be called the public labors of Henry
SO diligently performed in various fields after his advent to the
Smitiisonian Institution, it is well briefly to contemplate the
special scientific work he was able to accomplish in the intervals
of his exacting occupations ; that some estimate may be formed
of the independent value of his later contributions, as well as of
Ills wonderful industry. While still engaged in his difficult task
of organizing and shaping the policy of the Institution, in 1850,
on taking occasion to present before the American Association
at New Haven, Conn., a resume of the electrical phenomena
exhibited by the Leyden jar, and their true interpretation, he
remarked that " for the last three and a half years, all his time
and all his thoughts had been given to the details of the busi-
ness of the Smithsonian Institution. He had been obliged to
withdraw himself entirely from scientific research ; but he hoped
that now the Institution had got under way, and the Regents
had allowed him some able assistants, that he would be enabled
in part at least to return to his first love — the investigation of
the phenomena of nature."*

Thermal Telescope. — Shortly after his establishment at Wash-
ington, he continued a series of former experiments with the
" therrao-galvanic multiplicator" devised by Nobili and Melloni in
1831 ; and by some slight but significant modifications of the appa-
ratus, he succeeded in imparting to it a most surprising delicacy
of action. With the thermo-electric pile carefully adjusted at the

tliathe must see Mr. Lincoln personally, on a matter of vital and pressing
importance to the public welfare. This of course secured his admissiou
to the presence of Mr. Lincoln, who was sitting with a middle-aged gentle-
man. Observing the hesitancy of his visitor, the President told him lie
might speak freely, as only a friend was present. Whereupon the visitor
announced that for several evenings past he had observed a light exhib
itedon the highest of the Smithsonian towers, for a few minutes about
nine o'clock, with mysterious movements, which he felt satisfied were
designed as signals to the rebels encamped on Munson's Hill in Virginia.
Having gravely listened to this information with lai.-ed eyebrows, l>ut
a snbdued twinkle of the eye. the President turned to his companion,
saying " What do you think of that ? Professor Henry." Rising with a
smile," the person addressed replied, that from the time mentioned, he
presumed the mysterious light shone from the lantern of a watchman
who was required at nine o'clock each evening to observe and record the
indications of the meteorological instruments placed on the tower.

The painful confusion of the officious informant, at once appealed to
Henry's sensibility ; and qnite untiiindful of the President, he approached
the visitor, oflfering his hand, and with a courteons regard counselled him
never to be abashed at the issue of a conscientious discharge of duty,
and never to let the fear of ridicule interfere with its faithful execution.
* Proceed. Am. Assoc. 4tli Meeting, New Haven, Aug. 1850, p. 378.

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focus of a suitable reaector, his " thermal telescope" when directed
to the celestial vault, indicated that the heat radiated inward by
our atmosphere when clear, is least at the zenith, and increases
downward to the horizon ; as was to have been inferred from its
increasing mass : when directed to clouds, they were found to
differ very widely accordingly as they were condensing or being
dissipated ; some even indicating a less amount of radiation than
the surrounding atmosphere. When directed to a horse in a dis-
tant field, its animal heat concentrated on the pile, was distinctly
made manifest on the galvanometer needle. Even the heat from
a man's face at the distance of a mile could be detected ; and
that from the side of a house at several miles distance.* These
and many similar observations demonstrated to sense the induc-
tions of reason, that there is a constant and universal exchange
by radiation in straight lines from every object in nature, follow-
ing the same laws as the [)alpable emanation from incandescent
bodies ; and that even when the amplitude of the thermal vibra-
tions (equivalent to the square root of their dynamic energy) is
reduced a million fold, its existence may still be distinctly traced.

Henry showed by experiment, that ice could be employed both
as a convex lens for converging heat to a focus, and also as a
concave mirror for the same purpose : a considerable portion of
the incident rays being transmitted, a large portion reflected, and
the remainder absorbed by the ice.

He presented to the American Philosophical Society, a discus-
sion of the problem of the suspension of the ball in a water jet or
fountain. f

In 1849, for the purpose of estimating the effects of certain
meteorological conditions of the atmosphere, he made some ex-
periments on the lateral radiation from a current of ascending
heated air at different distances above the flame ; the latter being
thoroughly eclipsed.

He also experimented on the radiation of heat from a hydro-
gen flame, which was shown to be quite small, notwithstanding
the high temperature of the flame. By placing an infusible and
inconiljustible solid in the flame, while the temperature is much
reduced, the radiant light and heat are greatly increased J Re-
sults closely analogous to those he obtained in the differences
between the audibility of vibrating tuning-forks when suspended
by a soft thread, or when rigidly attached to a sounding-board.
These results have also an undoubted significance with regard
to celestial radiations ; not only as to the differences between
gaseous nebulte and stars or clusters, but as to the differences

* Sill Am. Jour. Sci. .Tan. 1848, vol. v. pp. 113. 114.
t Proceed. Am. Phil. Soc. Oct. 16, 1848, vol. iv. p. 285.
X Proceed. Am. Phil. Soc. Oct. 19, 1849, vol. v. p. 108.

100

nilLOSOPHlCAL SOCIETY OF WASHINGTON. 321

between stars in a probably diflferent state of condensation or of
specific gravity.

A few years later, he continued his investigation of this sul)ject
of radiation, more especially with reference to Rumford's " Ob-
servations relative to the means of increasing the quantities of
Heat obtained in the Combustion of Fuel :" published in Great
Britain in 1802.* He found that Rumford's recommendation of
the introduction of balls of clay or of fire brick (about two and a
half inches in diameter) into a coal fire, was fully justified as an
economic measure : more heat being thereby radiated from the
fire into the room, and less being carried up the flue. He also
showed however that for culinary purposes, while the incandes-
cent or heated clay increases the radiation, and thereby improves
the quality of the fire for roasting, it correspondingly expends
the temperature, and thereby diminishes its power for boiling.
" That a solid substance increases the radiation of the heat of a
flame, is an interesting fact in connection with the nature of heat
itself. It would seem to show that the vibrations of gross matter
are necessary to give sufficient intensity of impulse to produce
the phenomena of ordinary radiant heat."r

In 1851, he read before the American Association at Albany,
a paper " On the Theory of the so-called Imponderables :" (mainly
a development of his earlier discussion in 1846, of the molecular
constitution of matter,) in which he forcibly criticised a frequent
tendency to assume or multiply unknown and unrealizable modes
of action: holding that with regard to the most subtle agencies
of nature, we have no warrant by the strict scientific method, for
resorting to other than the observed and established laws of matter
and force, until it has been exhaustively demonstrated that these
are insufficient : and that time has not yet come. The funda-
mental laws of mechanical philosophy "are five in number; viz.,
the two laws of force — attraction, nnd repulsion, varying with
some function of the distance ; and secondly, the three laws of
motion — the law of inertia, of the co-existence of motions, and of
action and re-action. Of these laws we can give no explanation :
they are at present considered as ultimate facts ; to which all
mechanical phenomena are referred, or from which they are de-
duced by logical inference. The existence of these laws as has
been said, is deduced from the phenomena of the operations of
matter in masses ; but we apply them by analogy to the minute
and invisible portions of matter which constitute the atoms or
molecules of gases, and we find that the inferences from this as-
sumption are borne out by the results of experience." He re-
garded the modern kinetic or dynamic theory of gases, by its

* Jonrunl Roi/a! Instilution, 1802, vol. i. p. 28.

t Proceed. Am. Assoc. Providence, Ant;. 1855, pp. 112-116. "On the
ElTect of luingling Radiating substances with Combustible materials."

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328 BULLETIN OF THE

predictions and verifications, as furnishing almost a complete
tslablishment of tlie atomic and molecular theory of matter.
Referring to the ingenious hypothesis of Boscovich, he thought
that though well adapted to embrace the two static laws above
mentioned, it did not appear equally well adapted to satisfy in
any intelligible sense the three kinetic laws. He contended that
every attempt at conforming our conception of the ultimate con-
stitution of matter to the inductions of experience, would seem to
conduct us directly to the atomic hypothesis of Newton. A careful
study of the dynamics of the so-called "imponderables" certainly
tended to their unification. Admitting the difficulty of framing
an entirely satisfactory theory of the resultant transverse action
of electricity, he suggested that a tangential force was not accord-
ant with any inductions from direct experience ; and was incap-
able of direct mechanical realization. Extending the atomic
conception of matter to the setherial medium of space, he con-
cluded by urging "the importance in the adoption of mechanical
hypotheses, of conditioning them in strict accordance with tiie
operations of matter under the known laws of force and motion,
as exhibited in time and space."*

Among the various public Addresses delivered by Henry on
special occasions, reference may be here made to his excellent
exposition of the nature of power, and the functions of machinery
as its vehicle, concluding with a sketch of the progress of art,
pronounced at the close of the Exhibition of the Metropolitan
Mechanics' Institute, in Washington, on the evening of March
19th, 1853. After representing to his hearers the close physical
analogy between the human body as a moving machine, and the
steam locomotive under an intelligent engineer, he remarked:
" In both, the direction of power is under the influence of an
immaterial, thinking, willing principle, called the soul. But this
must not be confounded as it frequently is with the motive power.
The soul of a man no more moves his body, than the soul of the
engineer moves the locomotive and its attendant train of cars,
in both cases the soul is the directing, controlling principle; not
the impelling power. "t

Vieivs of Education. — Another address deserving of special
notice (delivered the following year,) is his introductory dis-
course before the "Association for the Advancement of Educa-
tion," as its retiring President. In this, he maintained that
inasmuch as "the several faculties of the human mind are not
simultaneously developed, in educating an individual we ought
to follow the order of nature, and to adapt the instruction to
the age and mental stature of the pupil. Memory, imitation,

* Proceed. Aw. Asanc. Albany, Aug 1851, pp. 84-91.

f Closing Address Metr. Mech. In.st. Washington, 1853, p. 19

102

PHILOSOPHICAL SOCIETY OF WASUINGTOX. 329

imagination, and the faculty of forming mental habits, exist in
early life, while the judgment and the reasoning powers are of
slower growth." Hence less attention should be given to the
development of the reasoning faculties, than to those of obser-
vation : the juvenile memory should be stored rather with facts,
than with principles: and he condemned as mischievous "the
proposition frequently advanced, that the child should be taught
nothing but what it can fully comprehend, and the endeavor in
accordance with this, to invert the order of nature, and attempt
to impart those things which cannot be taught at an early age,
and to neglect those which at this period of life, the mind is well
adapted to receive. By this mode we may indeed produce
remarkably intelligent children, who will become remarkably
feeble men. The order of nature is that of art before science;
the entire concrete first, and the entire abstract last. These two
extremes should run gradually into each other, the course of
instruction becoming more and more logical as the pupil advances
in years." — ■* The cultivation of the imagination should also be
considered an essential part of a liberal education : and this may
be spread over the whole course of instruction, for like the rea-
soning faculties the imagination may continue to be improved '
until late in liR'."

Applying this same reasoning to the moral training of youth,
he considered that (as in the intellectual culture) the object
should be "not only to teach the pupil how to think, but how to
act and to do; placing great stress upon the early education of
the habits. , . . We are frequently required to act from the
impulse of the moment, and have no time to deduce our course
from the moral principles of the act. An individual can be
educated to a strict regard for truth, to deeds of courage in res-
cuing others from danger, to acts of benevolence, generosity, and
justice. . . . The future character of a child and that of
the man also, is in most cases formed probably before the age
of seven years. Previously to this time impressions have been
made which shall survive amid the vicissitudes of life, amid all
the influences to which the individual may be subjected, and
which will outcrop as it were, in the last stage of his eaxthly
existence, when the additions to his character made in later years,
have been entirely swept away." Childhood (he intimated) is
less the parent of manhood, than of age : the special vices of the
individual child though long subdued, sometimes surviving and
re-appearing in his "second childhood,"

Affirming that culture is constraint, — education and direction
an expenditure of force, and extending his generalization from
the individual to the race, he controverted the idea so popular
with some benevolent enthusiasts, that there is a spontaneous
tendency in man to civilization and advancement. The origins
of past civilizations — taking a comprehensive glance at far dis-

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330 BULLETIN OF THE

tant human populations — liave been sporadic as it were, and
their prevalence comparatively transitory. "It appears there-
fore tliat civilization itself may be considered as a condition of
unstable equilibrium, which requires constant effort to be sus-
tained, and a still greater effort to be advanced. It is not in
my view the 'manifest destiny' of humanity to improve by the
operation of an inevitable necessar}' law of progress: but while
I believe that it is the design of Providence that man should be
improved, this improvement must be the result of individual
effort, or of the combined effort of many individuals animated
by the same feeling and co-operating for the attainment of the
same end. ... If we sow judiciously in the present, the
world will assuredly reap a beneficent harvest in the future :
and he has not lived in vain, who leaves behind him as his
successor, a child better educated — morally, intellectually, and
physically, than himself. From this point of view, the respon-
sibilities of life are immense. Every individual by his example
and precept, whether intentionally or otherwise, does aid or
oppose this important work, and leaves an impress of character
upon the succeeding age, which is to mould its destiny for weal
or woe, in all coming time. . . . The world however is
not to be advanced by the mere application of truths already
known : but we look forward (particularly in physical science)
to the effect of the development of new principles. We have
scarcely as yet read more than the title-page and preface of the
great volume of nature, and what we do k;iow is as nothing in
comparison with that which may be yet unfolded and applied."*

Experiments on Building-stone. — In 1854, a series of experi-
ments on the strength of different kinds of building-stone, was
undertaken by Henry as one of a commission appointed by the
I'resident, having reference to the marbles offered for the exten-
sion of the United States Capitol. Specimens of the different
samples — accurately cut to cubical blocks one inch and a half
in height, were first tried by interposing a thin sheet of load at
top and bottom, between the block and the steel plates of the

■* Proceed. Assoc. Adv. Education, 4th Session, Wasliington. Dec. 28,
1S.54, pp. 17-3'. The pregnant thought that huiiiau civilization is an
artificial and coerced condition, would seem to have a suggestive t>earing
on tlie two great theories of development and evolution, so generally con-
Inunded by tlie superficial. Wliat may be called tlie radical diffeience
1 etween these two views of organic extension, is that the former assumes
{tn inherent mysterious tendency to progression, whose motto is ever
'•excelsior;" while the latter assumes a general tendency to variation
within moderate limit* in indefinite directions; so that elevation is
no more normal than degradation, and indeed may be re^^arded as rarer
and more exceptional, sime at every upward stage attained by the few,
there are probably more further dii.'ressions dowuwar I tliau upward, the
iiiolto being ever '"aptiur.''

104

PHILOSOPHICAL SOCIETY OF WASHINGTON. 331

crusliinj^ dynamometer. " This was in accordance with a plan
adopted l)y Rennie, and tliat which appears to have been used
by most if not all of the subsequent experimenters in researches
of this kind. Some doubt however was expressed as to the
action of interposed lead, which induced a series of experiments
to settle this cpiestion ; when the remarkable fact was discovered
that the yielding and approximately equable pressure of the
lead caused the stone to give way at about half the pressure it
would sustain without such an interposition. For example, one
of the cubes precisely similar to another which withstood a pres-
sure of upwards of 60,000 pounds when placed in immediate
contact with the steel plates, gave way at about 30,000 pounds
with lead interposed. This interesting fact was verified in a
series of experiments eml)racing samples of nearly all the mar-
bles under trial, and in no case did a single exception occur to
vary the result.

" The explanation of this remarkable phenomenon (now that
the fact is known) is not difficult. The stone tends to give way
by bulging out in the centre of each of its four perpendicular
faces, and to form two pyramidal figures with their apices op-
posed to each other at the center of the cube, and their bases
against the steel plates. In the case where rigid equable pres-
sure is employed, as in that of the thick steel plate, all parts
must give way together. But in that of a yielding equable
pressure as in the case of interposed lead, the stone first gives
way along the outer lines or those of least resistance, and the
remaining pressure must be sustained by the central portions
around the vertical axis of the cube. After this important fact
was clearly determined, lead and all other interposed substances
were discarded, and a method devised by which the upper and
lower surfaces of the cube could be ground into perfect paral-
lelism. . . . All the specimens tested were subjected to this
process, and on their exposure to pressure were found to give
concordant results. The crushing force sustained was therefore
much greater than that heretofore given for the same material."*

In the same communication, interesting remarks are made on
the tensile strength of materials, particularly the metals. "Ac-
cording to the views presented, the difference in the tenacity in
steel and lead does not consist in the attractive cohesion of the
atoms, but in their capability of slipping upon each other:"
that is on the difference of lateral adhesion of the molecules, as
exem})lified in ice and water. A bar of soft metal — as lead —
subjected to tensile strain, by reason of the greater freedom of
the exterior layers of molecules, exhibits a stretching and
thinning; while the interior molecules being more confined by
the surrounding pressure, are less mobile, permit less elongation

* Proceed. Am. Af<soc. Providence, Aug. 1855, pp. 102 112.

105

332 BULLETIN OF THE

of the mass, and are therefore the first to commence breaking
apart. Accordingly on ultimate separation, each fragment ex-
hibits a hollow or cup-like surface of fracture, where the interior
portion of the material has first parted : the depth of the con-
cavity being somewhat proportioned to the malleability of the
substance. " With substances of greater rigidity, this effect is
less apparent, but it exists even in iron, and the interior fibres
of a rod of this metal may be entirely separated, while the outer
surface presents no appearance of change. From this it would
appear that metals should never be elongated by mere stretching,
but in all cases by a process of wire-drawing, or rolling. A wire
or bar must always be weakened by a force which permanently
increases its length without at the same time compressing it."*

Hyclrometric Experiment. — A novel project for the rectifica-
tion of spirits by the simple process of static separation of the
alcohol and water by the stress of their specific gravities when
exposed in long columns, produced in 1854 a considerable sensa-
tion. It was alleged that the coercitive compression exerted by
the water in a long hydrostatic column greatly accelerated the
displacement and separation induced by gravitation, and that
only a few hours were necessary to complete the process, if the
column were sufficiently high.t

A patent was obtained : afiidavit* and samples fully attested
the wonderful efficiency of the process ; and only the co-operation
of confiding capitalists was required, to realize fabulous profits,
and effect a manufacturing and commercial revolution.

Simply in tlie interests of truth, Henry undertook the careful
investigation of this surprising pretension. One of the towers of
the Smithsonian Building supplied a convenient well for the
experiment, easily accessible throughout its height. "A series
of stout iron tubes of about an inch and a half internal diameter
formed the column ; the total length of which was one hundred
and six feet. Four stop-cocks were provided ; one at the bot-
tom, one about four feet from the top, and the other two to the
intermediate space equally divided or nearly so." ^'ery careful
hydrometer and thermometer registers were made at increasing
intervals of time, the last being that of nearly half a year : a
portion of the reserved liquor being simultaneously tested. The
result stated, is : " There is not the slightest indication of any

* This conclu.sion is not at all in opposition to the ascertainerl fact of
the increased strengtli itnpaited to an iron rod l>y thermo-tension, dis-
covered by Prof. Walter R Johnson.

t An incidental remark in Gmelin's " Handbook of Cliemistrv" seemed
to give some color of plausibility to the scheme. " Brandy kept in casks
is said to contain a greater proportion of spirit in the npper, and of water
in the lower part." Gmelin's Hmulbook, Translated by Henry Watts.
London, 1841, part i. sect. 4, — vol. i. p. 112.

106

PHILOSOPHICAL SOCIETY OF WASHINGTON. 333

difference of density between the original liquor and that from
the top or bottom of tlie column, after the lapse of hours, days,
weeks, or months. The fluid at the bottom of the tube it must
be remembered was for five mouths exposed to the pressure of a
column of fluid at least one hundred feet high." *

Sulph.u7Hc-acid Barometer. — In 1856, Henry had constructed
for the Smithsonian Institution, at the suggestion of Professor
G. C. Schaeffer, a large sulphuric acid barometer, whose column
being more than seven times the height of the mercurial column
(about 18^ feet) gave correspondingly enlarged and sensitive indi-
cations. Water barometers with cisterns protected by oil, (as that
constructed by Daniell for the Royal Society,) have always proved
instable. With reference to sulphuric acid, " The advantages of
this liquid are : 1st that it gives off no appreciable vapor at any
atmospheric temperature ; and 2nd that it does not absorb or
transmit air. The objections to its use are : 1st the liability to
accident from the corrosive nature of the liquid, either in the
filling of the tube or in its subsequent breakage ; and 2nd its
af&nity for moisture, which tends to produce a change in specific
gravity." The latter defect was obviated by a drying apparatus
consisting of a tubulated bottle containing chloride of calcium,
and connected by a tube with the glass bottle forming the reser-
voir, which excluded all moisture from the transmitted air. " The
glass tube [of the barometer] is two hundred and forty inches
long, and three-fourths of an inch in diameter ; and is enclosed
in a cylindrical brass case of the same length, and two and a
half inches in diameter. The glass tube is secured in the axis
of the brass case by a number of cork collars, placed at inter-
vals, "f This barometer continued in successful and satisfactory
use for many years ; and had its readings constantly recorded.

Of several of Henry's courses of experiments, no details have
been published ; and his original notes appear to have perished.
In 18G1, he made a number of experiments on the effects of
burning gunpowder in a vacuum, as well as in different gases.

" A series of researches was also commenced, to determine
more accurately than has yet been done, the expansion produced
in a bar of iron at the moment of magnetization of the metal by
means of a galvanic current. The opportunity was taken with
the consent of Professor Bache, of making these experiments
with the delicate instruments which had previously been employed
in determining the varying length, under different temperatures,
of the measuring apparatus of the base lines of the United States
Coast Survey.".^ This wonderfully microscopic measuring appa-

* Proceed. Am. Asf^oc. ProvifJence, Au2 18.'").'), pp. 142, 143.
\ Proceed. Am. Asaoc. Albany, Aug. 1856, pp. 135-138.
J Smithsonian Report for 1861, p. 38,

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334 BULLETIN OF THE

ratus devised by Mr. Joseph Saxton, was capable of distinguish-
ing by the light-ray index of its contact reflector, a dimension
equal to a half wave-length of average light, or the 100,000th
part of an inch. The long under-ground vaults of the Smith-
sonian building having been selected as a suitable place for the
precise verification of the residual co-efficient of compensated
temperature expansion of the base rods of the Survey, the oppor-
t unity was seized by Henry, at the termination of the investiga-
tion, to apply the same delicate apparatus to the determination
of the polarized or magnetic expansion.

In less than six years from the time of these researches, he
was called on to mourn the death of his life-long intimate and
honored friend, who had always exhibited so fraternal a sympathy
and co-operation with his own varied labors. In consequence of
this event — the death of his friend Professor A. Dallas Bache in
1867, Henry was chosen in 1868, to be his successor as President
of the National Academy of Sciences. At the request of that
body, he prepared a eulogy of his friend the late President, which
was read before the Academy April 16th, 1869. In grateful ac-
knowledgement of the wise counsels and valuable services of Dr.
Bache as one of the Regents of the Smithsonian Institution for
nearly twenty years, he observed: "To say that he assisted in
shaping the policy of the establishment would not be enough.
It was almost exclusively through his predominating influence
that the policy which has given the Institution its present celeb-
rity, was after much opposition finally adopted. . . Nor
would it be possible for him [the speaker] to abstain from ac-
knowledging with heart-felt emotion, that he was from first to
last supported and sustained in his difficult position by the fra-
ternal sympathy, the prudent counsel, and the unwavering friend-
ship of the lamented deceased."*

Many minor contributions in various fields of scientific obser-
vation, must here be omitted : but it would be inexcusable, in
this place and on this occasion, to neglect a reference to the
active i)art he took in the organization and advancement of this
Society ;f and the unflagging interest ever exhibited in its pro-
ceedings, from the date of its convocation, March 18th, 1871, to
that of his last illness. All here remember with what punctu-
ality he attended the meetings — whether of the executive com-
mittee or of the society, undeterred by inclemencies of the
weather which kept away many much younger members. All

* Biogrophicnl Memoirx, Not. Acad. Sci. vol. i. pp. ] 81-212. Rt^puli-
lislied in tlie Smithsonian Report tor 1870, pp. 91-1](!. The father of Prof.
BacliH — Richard BMche, was a sou of the only daughter of th>- ilhistrioud
Benjamin Franklin.

I The Philosophical Society of Washington.

1U8

PHILOSOPHICAL SOCIETY OF WASHINGTON. 335

here, recall with what unpretentious readiness he communicated
from his rich stores of well-digested facts, observations— whether
initiatory or supplementary, on almost every topic presented to
our notice ; how apt his illustrations and suggestions in our
spontaneous discussions; and with what unfailing interest we
ever listened to his words of exposition, of knowledge, and of
wisdom : utterances which we shall never hear again ; and which
unwritten and unrecorded, have not been even reported in an
abstract.

Range of information. — It was not alone in those physical
branches of knowledge to which he had made direct original con-
tributions, that the mental activities of Henry were familiarly
exercised and conspicuously exhibited. There was scarcely a
department of intellectual pursuit in which he did not feel and
manifest a sympathetic interest, and in which he did not follow
with appreciative grasp its leading generalizations. Holding
ever to the unity of Nature as the expression and most direct
illustration of the Unity of its Author, he believed that every
new fact discovered in any of nature's fields, would ultimately
be found to be in intimate correlation with the laws prevailing in
other lields — seemingly the most distant.* To his large compre-
hension, nothing was insignificant, or unworthy of consideration.
He ever sought however to look beyond the ascertained and iso-
lated or classified fact, to its antecedent cause ; and in opposition
to the dogma of Comte, he averred that the knowledge of facts
is not science, — that these are merely the materials from which
its temple is constructed by sagacious and attested speculation.

Among his earlier studies, Chemistry occupied a prominent
place. The youthful assistant in the laboratory of his former
instructor and ever honored friend. Dr. T. Romeyn Beck, and
later, himself a teacher of the art and knowledge to others, a
skilful manipulator, an acute analyst and investigator of re-ac-
tions, he seemed at first destined to become a leader in chemical
research. Like Newton, he endeavored to bring the atomic
combinations under the conception of physical laws ; believing
this essential to the development of chemistry as a true science.
He always kept himself well informed on the progress of the
more recent doctrines of quantivalence, and the newer system of
nomenclature.

He had also paid considerable attention to geology ; with its
relations to palgeontology on the one side, and to physical geog-
raphy on the other.

Familiar with the details — as well of astronomical observation

* " A proper view of the relation of science and art will enable liim
[the reader] to see that tlie one is dependent on the other ; ai.d that each
branch of tlie study of nature is intimately connected with every other."
{Agricultural Report for 1S57, p. 419.)

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336 BULLETIN OF THE

as of the mathematical processes of reduction, he would have
done honor to any Observatory placed under his charge. He
was lenient in his judgment of the ancient star-woi'shippers ; and
was always greatly attracted by astronomical discoveries.

Well read in the science of Political Economy, he had by
observation and analysis of human nature, made its inductive
principles his own, and had satisfied himself that its deductions
were fully confirmed by an intelligent appreciation of the teach-
ings of financial history. He attributed tlie lamentable disregard
of its fundamental doctrines, by many so-called legislators, to a
want of scientific training, and consequent want of perception
and of faith in the dominion and autonomy of natural law.

A good linguist, he watched with appreciative interest the
progress of comparative philology, and the ethnologic significance
of its generalizations, in tracing out the affiliations of European"
nations. By no means neglectful of lighter literature, he enjoyed
at leisure evenings, in the bosom of his cultivated family, the
readings of modern writers, and the suggestive interchange of
sentiment and criticism. Striking passages of poetry made a
strong impression on his retentive memory ; and it was not un-
usual to hear him embellish some graver fact, in conversation,
with an unexpected but most apt quotation. With a fine festhetic
feeling, his appreciation and judgment of works of art, were
delicate and discriminating.

He held very broad and decided views as to the reign of order
in the Cosmos. Defining science as the "knowledge of natural
law," and law as thx " will of God," Henry was always accus-
tomed to regard that orderly sequence called the "law," as being
fixed and immutable as the providence of its Divine Author:
admitting in no case caprice or variableness. The doctrine of
the absolute dominion of law — so oppressive and alarming to
many excellent minds, was to him accordingly but a necessary
deduction from his theologic and religious faith.

The series of meteorological essays already referred to as
contributed to the Agricultural Reports of the Commissioner
of Patents, commences with this striking passage, "All the
changes on the surface of the earth and all the movements of the
heavenly bodies, are the immediate results of natural forces
acting in accordance witli established and invariable laws ; and
it is only by that precise knowledge of these laws, which is pro-
perly denominated science, that man is enabled to defend himself
against the adverse operations of Xature, or to direct her innate
powers in accordance with his will. At first sight, it might
appear that meteorology was an exception to this general propo-
sition, and that the changes of the weather and the peculiarities
of climate in different portions of the earth's surface, were of all
things the most uncertain and farthest removed from the dominion

110

PHILOSOPHICAL SOCIETY OF WASHINGTON. 337

of law: but scientific investigation establishes the fact that no
phenomenon is tlie result of accident, or even of fitful volition.
The modern science of statistics has revealed a permanency and
an order in the occurrence of events depending on conditions
in which nothing of this kind could have been supposed. Even
those occurrences which seem to be left to the free will, the pas-
sion, or the greater or less intelligence of men, are under the
control of laws — fixed, immutable, and eternal." And after
dwelling on the developments and significance of moral statistics,
he adds: "The astonishing facts of this class lead us inevitably
to the conclusion that all events are governed by a Supreme In-
telligence who knows no change ; and that under the same con-
ditions, the same results are invariably produced."*

Organic Dynamics. — The contemplation of these uniformities
leads naturally to the great modern generalization of the correla-
tion of all the working energies of nature : and this to the subject
of organic dynamics. "Modern science has established by a wide
and careful induction, the fact that plants and animals consist
principally of solidified air ; the only portions of an earthy cha-
racter which enter into their composition, being the ashes that
remain after combustion." Some ten years before this, or in
1844, (as already noticed in an earlier part of this memoir)
Henry had very clearly indicated the correlation between the
forces exhibited by inorganic and organic bodies : arguing that
from the chemical researches of Liebig, Dumas, and Boussin-
gault, " it would appear to follow that animal power is referable
to the same sources as that from the combustion of fuel :"t
probably the earliest explicit announcement of the now accepted
view. In the series of agricultural essays above referred to,
he endeavored to frame more definitely a chemico-physical
theory by which the elevation of matter to an organic combina-
tion in a higher state of power than its source, might be ac-
counted for. Regarding "vitality" not as a mechanical force,
but as an inscrutable direcfing principle resident in the minute
germ — supposed to be vegetative, and enclosed in a sac of
starch or other organic nutriment, he considered the case of
such provisioned germ (a bean or a potato) embedded in the
soil, supplied with a suitable amount of warmth and moisture

* Agricultural Rpport Com. Pat. for LS55, p. 357.

t Proceed. Am. Phil. Soc. Dec. 1S44, vol. iv. p. 129. The admirable
treatise of Dr. .Tulins R. Mayer of Heilbronn, on " Oiganlc Movement in
its relation to material changes," in which for the first time lie main-
tained the thesis that all the energies developed by animal or vegetable
organisms, result from internal changes having their dynamic source in
external forces, was published the following year, or in 1845. Rumford
nearly half a century earlier, had a partial grasp of \\\t^ same trntli.
{Phtl. Trans. R. S. Jan. 25, 1798, vol. Ixxsviii. pp. 80-1U2.)

VOL. II. — 22 111

338 BULLETIN OF THE

to give the necessary molecular mobility, soon sending a rootlet
downward into the earth, and raising a stem toward the sur-
face, furnished with incipient leaves. Supposing the planted
seed to be a potato, on examination we should find its large sup-
ply of starch exhausted, and beyond the young plant, nothing
remaining but the skin, coutaining probably a little water. What
has become of the starch ? " If we examine the soil which sur-
rounded the potato, we do not find that the starch has been
absorbed by it ; and the answer which will therefore naturally
be suggested, is that it has been transformed into the mate-
rial of the new plant, and it was for this purpose originally stored
away. But this though in part correct, is not the whole truth :
for if we weigh a potato prior to germination, and weigh the
young plant afterward, we shall find that the amount of organic
matter contained in the latter, is but a fraction of that which
was originally contained in the former. We can account in this
way for the disappearance of a pari of the contents of the sac,
which has evidently formed the pabulum of the young plant.
But here we may stop to ask another question : By what power
was ihe young plant built up of the molecules of starch ? The
answer would probably be, by the exertion of the vital force :
but we have endeavored to show that vitality is a directing prin-
ciple, and not a mechanical power, the expenditure of which does
work. The conclusion to which we would arrive will probably
now be anticipated. The portion of the organic molecules of
the starch, etc., of the tuber, as yet unaccounted for, has run down
into inorganic matter, or has entered again into combination
with the oxygen of the air, and in this running down and union
with oxygen, has evolved the power necessary to the organization
of the new plant. . . . We see from this view that the starch
and nitrogenous materials in which the germs of plants are im-
bedded, have two functions to fulfil, the one to supply the pabu-
lum of the new plant, and the other to furnish the power by
which the transformation is effected, the latter being as essential
as the former. In the erection of a house, the application of
mechanical power is required as much as a supply of ponderable
materials."*

t Acjricultuial Report, for 1857, pp. 440-444 111 May, ]8-'2, Dr. Julius
R. Mayer published in Liel>ig's Annalen der Chemie, etc., his first remark-
able paper on "The Forces of Inorganic Nature," constituting the earliest
scientific enunciation of the correlation of the physical forces ; and (if
we except the work of Seguiu in 1839,) of the mechanical equivalent of
heat. {Autidlen u.s.w. vol, xlii. pp. 233-240.) In September, 1849,
Dr. R. Fowler read a shoit paper before the British Association at Bir-
mingham, on " Vitality as a Foice correlated witli the Fhysiial Foices."
(Report Brit. Assoc. 1849, part ii. pp. 77, 78.) In June, 1850, Dr. \V. B.
Carpenter presented to the Royal Society a much fuller memoir " On the
Mutual Relations of the Vital and Fhysical Forces." {Phil. Trans. R,
S. vol. cxl. pp. 727-757.) Neither of these essays accounts for the

112

PHILOSOPHICAL SOCIETY OF WASHINGTON. 339

The less difficult problem of the building up of the plant after
the consumption of the seed, under the direct action of the solar
rays, is then considered ; the leaves of the young plant absorbing
by their moisture carbonic acid from the atmosphere, which being
decomposed by solar actinism, yields the de-oxidized carbon to
enter into the structure of the organism. "All the material of
which a tree is built up, ('with the exception of that comparatively
small portion which remains after it has been burnt, and con-
stitutes the ash,) is derived from the atmosphere. In the decom-
position of the carbonic acid by the chemical ray, a definite
amount of power is expended, and this remains as it were locked
up in the plant so long as it continues to grow." And thus
under the expenditure of an external force, the plant (whether
the annual cellular herb or the perennial fibrous tree) was shown
to be built up from the simpler stable binary compounds of the
inorganic world, to the more complex and unstable ternary com-
pounds of the vegetable world. " In the germination of the
plant, a part of the organized molecules runs down into carbonic
acid to furnish power for the new arrangement of the other por-
tion. In this process no extraneous force is required : the seed
contains within itself the power, and the material, for the growth
of the new plant up to a certain stage of its development. Ger-
mination can therefore be carried on in the dark, and indeed the
chemical ray which accompanies light retards rather than accele-
rates the process." (p. 446.) This important organic principle
appears to receive he.re its earliest enunciation.

It was also pointed out that on the completion of the cycle of
growth (however brief or however extended), the decay of the
plant not only returns the elevated matter to its original lower
plane, but equally returns the entire amount of heat energy ab-
sorbed in its elevation : an amount precisely the same, whether
the slow oxidation be continued through a series of years, or a
rapid combustion be completed in as many minutes. " The
power which is given out in the whole descent is according to
the dynamic theory, just equivalent to the power expended by
the impulse from the sun in elevating the atoms to the unstable
condition of the organic molecules. If this power is given out
in the form of vibrations of the aetherial medium constitutinu:
heat, it will not be appreciable in the ordinary decay say of a
tree, extending as it may through several years : but if the pro-
cess be rapid, as in the case of combustion of wood, then the
same amount of power will be given out in the energetic form
of heat of high intensity."

The elevation of inorganic matter (carbonic acid, water, and

amount of building energy displayeii in the development of the seed,
under conditions of low and diffused heat: and the expression "Vital
Force" used both by Fowler and Carpenter, was studiously avoided by
Henry.

113

340 BULLETIN OF THE

ammonia,) to the vegetable plane of power, introduces naturally
the consideration of the still higher elevation of vegetable or-
ganic matter to the animal plane of power. "As in the case of
the seed of the plant, we presume that the germ of the future
animal pre-exists in the egg; and that by subjecting the mass to
a degree of temperature sufficient perhaps to give greater mobility
to the molecules, a process similar in its general effect to that
of the germination of the seed commences. . . . During this
process, power is evolved within the shell, we cannot say in the
present state of science under what particular form ; but we are
irresistibly constrained to believe that it is expended under the
direction again of the vital principle, in re-arranging the organic
molecules, in building up the complex machinery of the future
animal, or developing a still higher organization, connected with
which are the mysterious manifestations of thought and volition.
In this case as in that of the potato, the young animal as it
escapes from the shell, weighs less than the material of the egg
previous to the process of incubation The lost material in this
case as in the other, has run down into an inorganic condition by
combining with oxygen, and in its descent has developed the
power to effect the transformation we have just described."
The consumption of internal power does not however stop
with the development of the young animal, as it does in the
case of the young plant. " The young animal is in an en-
tirely different condition: exposure to the light of the sun is not
necessary to its growth or its existence : the chemical ray by
impinging on the surface of its body does not decompose the car-
bonic acid which may surround it, the conditions necessary for
this decomposition, not being present. It has no means by itself
to elaborate organic molecules ; and is indebted for these entirely
to its food. It is necessary therefore that it should be supplied
with food consisting of organized materials; that is of complex
molecules in a state of power. . . . The power of the living ani-
mal is immediately derived from the running down of the com-
plex organized molecules of which the body is formed, into their
ultimate combination with oxygen, in the form of carbonic acid
and water, and into ammonia. Hence oxygen is constantly
drawn into the lungs, and carbon is constantly evolved. . . .
The animal is a curiously contrived arrangement for burning car-
bon and hydrogen, and for the evolution and application of power.
A machine is an instrument for the application of power, and
not for its creation. The animal body is a structure of this
character. ... A comparison has been made between the work
which can be done by burning a given amount of carbon in
the machine — man, and an equal amount in the machine — steam-
engine. The result derived from an analysis of the food in one
case, and the weight of the fuel in the other, and these compared
with the quantity of water raised by each to a known elevation,

114

PHILOSOPHICAL SOCIETY OF WASHINGTON. 341

gives the relative working value of the two machines. From
this comparison, made from experiments on soldiers in Germany
and France, it is found that the human machine in consuming
the same amount of carbon, does four and a half times the
amount of work of the best Cornish engine."

" There is however one striking difference between the animal
body and the locomotive machine, which deserves our special
attention ; namely the power in the body is constantly evolved
by burning (as it were,) parts of the materials of the machine
itself; as if the frame and other portions of the wood-work of the
locomotive were burnt to produce the power, and then imme-
diately renewed. The voluntary motion of our organs of speech,
of our hands, of our feet, and of every muscle in the body, is
produced not at the expense of the soul but at that of the ma-
terial of the body itself. Every motion manifesting life in the
individual, is the result of power derived from the death as it
were of a part of his body. We are thus constantly renewed
and constantly consumed ; and iu this consumption and renewal
consists animal life."*

Seven years after the publication of this highly original and
suggestive exposition, (whose topics and line of discussion had
been distinctly formulated and sketched out more than two years
before, at the commencement of the series in 1855,) the eminent
physiologist Dr. Carpenter produced his valuable memoir on the
Conservation of Force in Physiology; in which he for the first
time distinctly affirms the development of vegetative reproductive
energy, by the partial running down of matter to its stabler
compounds, — " by the retrograde metamorphosis of a portion of
the organic compounds prepared by the previous nutritive ope-
rations :" and also the ultimate return by decay, of the whole
amount of force as well as of matter, temporarily borrowed from
nature's store. Likewise with animal powers, " these forces are
developed by the retrograde metamorphosis of the organic com-
pounds generated by the instrumentality of the plant, whereby
they ultimately return to the simple binary forms (water*, car-
bonic acid, and ammonia,) which serve as the essential food of
vegetables. . . Whilst the vegetable is constantly engaged

(so to speak) in raising its component materials from a lower
plane to the higher, by means of the power which it draws from
ihe solar rays, — the animal whilst raising one portion of these to

* AgricAiltural Report for 1857, pp. 445-449. This inipoitaut essay it
will be observed, antedates Prof. Josepli Le Conte's paper " On the Corre-
lation of Physical, Chemical, and Vital Force," read before the American
Association at Springfield, Aug. 1859, (Proceed. Am. Assoc, pp. 187-203:
and Sill. Am. Jour. Sci. Nov. 1859, vol. xxviii. pp. 305-319,) as well as
Dr. Carpenter's second and more mature paper "On the application of
the Principle of Conservation of Foice to Physiology," published in
Crookes' Quarterly Jourtia/ of Science, for Jan. and April, 1864. (vol. i. pp.
76-87; audpp. 259-277.)

115

342 BULLETIN OF THE

a still higher level by the descent of another portion to a lower,
ultimately lets down the whole of what the plant had raised.'"*
So little was Henry's earlier paper known abroad, that his name
does not occur in l)r. Carpenter's dissertation.

With regard to the great biologic question of the past fifteen
years — the affiliation of specific forms, it was impossible that
Henry should remain an unconcerned observer. Brought up (as
it may be said) in the school of Cuvier, but slightly impressed
with the brilliaiit previsions of his competitor, Geoffroy Saint
Hilaire, accustomed to look upon the recurrent hypotheses of
automatic development as barren speculations, and beside all
this, ever the warmly attached personal friend of Agassiz,
he approached the consideration of this controverted subject,
certainly with no antecedent affirmative pre-possessions. His
general acquaintance with the ascertained facts of the metaraor-
phic development of the individual organism from its origin, as
well as with the remarkable analogies and homologies disclosed
by the sciences of comparative physiology and embryology, served
however in some measure to prepare his mind to apprehend the
significance of the indications which had been so industriously
collected, and so intelligently collated : and from the very first,
he accepted the problem as a purely philosophical one ; employ-
ing that much abused term in no restricted sense. "With no
more reserve in the expression of his views, than the avoidance
of unprofitable controversies, (though no one more than he —
enjoyed the calm and purely intellectual discussion of an unset-
tled question by its real experts,) he yet found no occasion to
write upon the subject. The unpublished opinions however, of
one so wise and eminent, cannot be a matter of indifference to
the student of nature ; and their exposition cannot but assist to
enlighten our estimate of the mental stature of the man, and of
his breadth of appi-ehension and toleration.

Whatever may be the ultimate fate of the theory of natural
selection, (he remarked in the freedom of oral intercourse with
several naturalists,) it at least marks an epoch, the first eleva-
tion of natural history (so-called) to the really scientific stage :
it is based on induction, and correlates a large range of ap-
parently disconnected observations, gathered from the regions
of palaeontology or geological successions of organisms, their
geographical distribution, climatic adaptations and remarkable
re-adjustments, their comparative anatomy, and even the occur-
rence of abnormal variations, and of rudimentary structures —
seemingly so uselessly displayed as mere simulations of a
"type." It forms a good "working hypothesis" for directing

* Qiuirt. Jour. Sci. 1864, vol. i. pp. 8G and 2(37.
116

PHILOSOPHICAL SOCIETY OF WASHINGTON. 343

the investigations of the botanist and zoologist.* Natural selec-
tion indeed — no less than artificial (he was accustomed to say),
is to a limited extent a fact of observation ; and the practical
question is to determine approximately its reach of application,
and its sufficiency as an actual agency, to enibvace larger series
of organic changes lying beyond the scope of direct human ex-
perience. It is for the rising generation of conscientious zoolo-
gists and botanists to attack this problem, and to ascertain if
practicable its limitations or modifications.

These broad and fearless views, entertained and expressed as
early as 1860, or 1861, exhibiting neither the zealous confidence of
the votary, nor the jealous anxiety of the antagonist, received
scarcely any modification during his subsequent years. Nor did
it ever seem to occur to hira that any reconstruction of his reli-
gious faith was involved in the solution of the problem. So
much religious faith indeed was exercised by him in every scien-
tific judgment, that he regarded the teachings of science but as
revelations of the Divine mode of government in the natural
world: to be diligently sought for and submissively accepted;
with the constant recognition however of our human limitations,
and the relativity of human knowledge. f Not inappropriately
may be here recalled a characteristic statement of the office of
hypothesis, made by him some ten years earlier : presenting a
consideration well calculated to restrain dogmatism — whether in
science or in theology. " It is not necessary that an hypothesis
be absolutely true, in order that it may be adopted as an expres-
sion of a generalization for the purpose of explaining and pre-
dicting new phenomena : it is only necessary that it should be
well conditioned in accordance with known mechanical prin-
ciples. . . . Man with his finite faculties cannot hope in
this life to arrive at a knowledge of absolute truth : and were
the true theory of the universe, or in other w^ords the precise
mode in which Divine Wisdom operates in producing the phe-
nomena of the material world revealed to him, his mind would
be unfitted for its reception. It would be too simple in its ex-
pression, and too general in its application, to be understood
and applied by intellects like ours. "J

* "In the investigation of nature, we provisionally adopt hypotheses
as antecedent probabilities, which we seek to prove or disprove by sub-
sequent observation and experiment : and it is in this way that science
is most rapidly and securely advanced." (Agricult. Report, 1856, p. 456.)

f With reference to the intimations of the comparative antiquity of
man, Henry quoted with sympathetic approbation the sentiment so Well
expressed by the Bishop of London in a Lecture at Edinburgh, that "The
man of science should go on honestly, patiently, diffidently, observing
and storing up his observations, and carrying his reasonings unflinch-
ingly to their legitimate conclusions, convinced that it would be treason
to the majesty at once of science and of religion, if he sought to help
either by swerving ever so little from the straight line of truth." {Smith-
sonian Report for 1868, p. 33.)

i Proceed. Am. Assoc. Albany, Aug. 1851, pp. 86, 87.

117

844 iji;li,ktin «k tjik

INVIiBTIUATlONS IN ACOUSTICS.

T)iiriii<f llu! IiikI, (|imrlcr of a ccMtiiry, nmnw^ llin timiiy inloroRts
wliicli (lciiiiiii(l(r(l mill nigii^cd IiIh iilUMilioii, I iciiry Kliidit il with
miicli euro viirioiiM iilniiomciia of ncouHlicH, and added iniicli to
our pracliral an well »h tlicor(!ti<;ttI kiiowlcdj^o of lliis imporluiit
iiislruiMCiifiilily. In ]H')|, lio nuid a commiinicalion Ixiforo the
A nicriciin AsHociaf ion, " On ilio jyimil. of l*crc('|)l il)ility of a direct
mid ridlectod Honnd," in whielt ho j^avo M tlio roKiiIt, of e\|>(ii-
iiirntftl oliKcrviil ionK, (lio Kid)jectiv(! fiiet thnt a widl or other r(tlleet-
inj; Hiirfaco if lieyond tlic; distanco (d' alioiit .'JTi fot from tlic cur,
or from tlio origin of tlio sound, givc.H a (liKtingnishal)lo echo from
tho Bound ; luit tliiit if tlio ear or tlio Bonnding agent I)0 iiliiccd
within thin diKliince, th(i rellcclcd Koiind appcarK to Ideml (rom-
pl(!((dy with tlie original oik;. I''rom a iinnil)er of cxperiinentK, lio
found thitt ninl< i- tho nanio circiunKtaneoH, tliiB limit of ])erc('pli-
liility did not, vmy nmre tlniii a ninglo foot; Imt thnt under dilVer-
ing conditioiiH tlio limit of distance ranged from UU to K) foot,
(o(piival«fit to ft dilToronco of from (JO to HO foot of Bound travol,)
depending partly on tho KluirpncKH or clearnosH of tho Bound, and
j)artly on tlio pitch or tlio length of tlii! HoniforoiiH wave, which
all'irctod tho nniomit of overlapping of tho two KcrioH. TheHO re-
MiltB im|)ly (I dnniiiiMi of ncouBlio improBHion on tho oar of nlioui
oiio-Hixteenlli <d' a second; serving to show that \(', viliralionH to
tho BOC'iMid must lio alioiit I ho lower limit of a recogni/.uMe musi-
cal tone* Ah applied to looturc-rooinB, ho pointed out, tlmi iln-
ceiling hlioul'i not \u' inori! than oKoiit thirty feet high, within which
elevation, a smooth coiling would tend to re-inforco tho sound of
a s|»oakor's voice f

Many oxperimentu wore afterward made on Iho roKonanro of dif-
ferent nmt.erials, hy nieauH of tuning I'lirlis. While a tuning fork
suHjieiidid hy a lino thread <M)nliiiued to vil)riite for ujiward of jour
ininntoH with Bciircoly any npprooiahlo Bouinl, if placed in contact
wilh tho lop of a |iino lidile, Iho sanio vihration continuei] hut
ton Bcconds, hut gavo a loud full tone. On a marhle topped
table tho Bound wan much more feeble, and the vibration conlinuod
nearly two niinntoH. While tho tiiiiing fork against a Ijrick wall
gavo a feebin lone continuing for KS secondK, against a lath and
plaster partition it gave a sound considerably louder but continu-

* Tliirt doort iidt i«oi>ni io nf^rct* with remiltH elilfilneil l.y Sfivart Borne
twenty yofiiK jhi-vIoubI y ; who (loiuiliiiltid from olinni vnlioiiH with ll»i» siron,
" Ihul hdhiiiIk ftio iliKlinnlly |MT('i<|>til)lo, niiil ov«'ii Mlroii« wlioii (!onip(»Hed
of no inont limn t-iglil vibialiouM in jiboooikI." (/uu, Knctjil. July, 1H32.
Quolwd in Hill. Am. Jour, Sei. for 1832, vol. xxil. p. 374.) ' ThlH latter do-
torniiiiiition Ih Buniowloit (linirnlt to ni'onciht with oritinnry ohMxrvntioiiB,
n« ll irt (Mrl/iln lliiil intciviilM of onr ciglilli of a Kccon I woviht glvo (i vcr/
fi|>|iii<i'ifili|« r/illlo to nlnio^l ovcry cftr.

I /'iiirrnl. Am. AiiiKtc. Clnoinufttl, May, 18.'1, pp. 42, 43.

118

riiiLOBorinoAii society of wasiiinqton. IMT)

liifj; only 18 kcooikIs. Oh a li»,rf.'0 hlofk of soft Iiidia-riihlicr rcHt-
iiifi^ on tlio uiiuldt) hIuI), tlu! vihruliuii wan very nipidly cxUn-
{jjuisluid, hut without givinj^ any 8cii8iI)I« Konnd. 'I'liin luionuily
rcMjiiirr.d nn f.xpliiruUion. Uy niciuiH <ii' a c()ni|H)iin<l wiio of (-(iiiiicr
and iron inHcrttid into tlu! pioc-t; ul' iiiltbcr, and liavin}^- tlio lixtrcnii-
ties conncctcti witii a tiu!rnio-galvaiioincl(!r it was I'onnd tliat in
this caso tho acoustic vil)ratioii8 wcro convurtcd into heat. Hhoctw
of India-riiblxT thcircforo are ainonj; the Ix'st ahsorltcrs and de-
stroyers of sound. A series ol' experiments was also made on tlio
rtilieetioii of sound, to deterniiuo tho materials least and those best
atlapted to this purpose. A resume of these researches, haviti}^-
reference to tlie acoustic properties of put)lic iuills, was read beforo
the American Association in August, 1800.

In 18(i5, as Chairman of the Connnitteo of Experiments of the
U. H. Iiight-hous(! Hoard, ileury eommeiu-ed an extended series
of observations on tlie ctondiiet and intensity of sound at a distance,
\inder varying ni<;t(!orologicid conditions. Weil awan; (hat for llio
practical purposes of giving increased security t(j navigation, llui
experiments of tho laboratory were of little value, he nnderlooli a
number of experimental trips on board sailing vessels, ami on
steamers, in order to make his observations under the actual con-
ditions of the recpiired service!. As many of his investigations
re(|uircd intellig(!nt co-operation, and som(;limes at the distances
of many miles, he associated with him at dilVerent times, among
m(!mbers of the Light-house hibitablitiliment. Commodore I'owell,
Commodore Case, Ailnural Trenchard, Commander Walker, Cap-
tain Upshur, (Jeneral I'oe, (leneral liarnard, (ieneral Woodrulf,
Mr. Ledei'le, and other engiru-ers of dilferent liighl-hoiise Dis-
tricts, and outside of the establishment. Dr. Welling and others.

At thoouthct of his experiments, he found that sound rellectors,
which play so interesting a part in lecture room exhibitions, were
practically worthless (of whatever availalde dim<;uhions) for the
|)urpose of directing or concentrating powerful sounds to any con-
siderable distatice. At the distance of a mile or two a large
steam whistle phured in the focus of a concave reflector 10 feet in
diameter co.dd be heard very nearly as well directly behind tho
reflector, as directly In front of it. in like manner the direction
of bell-mouths and of trum|)et-mouths, was found to la; of com-
paratively littli! im|>ortauce at a <listanco ; showing the rcinnirlvablo
tendency to dilfusion, especially with very loud sounds. Most of
the observations made on shi|)- board were afterward repeateil on
land ; and several weeks were occupied with these important re-
searches.

" During this series of investigations an interesting fact was dis-
coveriMl, na,mely, a soun<l moving against the wind, inaudible to
the ear on the deck of the si'hooticir, was heard by ascending to the
niastdicad. This remarkable fact at flrst suggested the idea that

110

346 BULLETIN OP THE

sound was more readily conveyed by ihe upper current of air than
the lower." After citing observations by others apparently con-
firming the suggestion of some dominant influence in the upper
wind, Henry adds : " The full significance however of this idea did
not reveal itself to me until in searching the bibliography of sound,
I found an account of the hypothesis of Professor Stokes in the
Proceedings of the British Association for 1857,* in which the
effect of an upper current in deflecting the wave of sound so as to
throw it down upon the ear of the auditor, or directing it upward
far above his head, is fully explained.""}" A rough attempt was
made in the course of these observations (which were undertaken
at the light-house near New Haven, Connecticut) to compare
the velocity of the wind in the upper regions with that near the
surface of the earth. "The only important result however was
the fact that the velocity of the shadow of a cloud passing over
the ground was much greater than that of the air at the surface,
the velocity of the latter being determined approximately by run-
ning a given distance with such speed that a small flag was at rest
along the side of its pole. While this velocity was not perhaps
greater than six miles per hour, that of the shadow of the cloud
was apparently equal to that of a horse at full speed."!

In October, 18G7, a series of observations was made at Sandy
Hook (Xew Jersey) with various instruments. A sound reflector
being employed, the distance at which the sand on the phonometer
drum — carried in front, ceased to move was 51 yards, as compared
with a distance of 40 yards, without the reflector. At a greater
distance, with a more sensitive instrument, the ratio was very much
diminished. Experiments were also made on the relative distances
at which the trumpet affected sensibly the drum of the phonometer
in different directions, giving as their result a limiting spheroid
whose reach in the forward axis of the trumpet was about double
that in the rear axis, and at right angles to the axis, was about a
mean proportional between tiie two. With greater distances,
these differences were evidently very much reduced, the radii
becoming more equalized. In the summer of ISTl, Henry made

* Report Brit. Assoc, vol. xxiv. 2d part, p. 27.

t Report of Light House Board, U. S. for 1S74, p. 92.

i Tliis difference has since been established by a number of independ-
ent observations. Mr. Glaisher from his balloon ascents in 18U3-18G5,
ascertained that the upper currents of air are frequently five or six times
more rapid than the surface currents. (Travels in the Air, p. 9.) Prof.
Cleveland Abbe remarks : " From seven balloon ascensions made on .July
4th, 1871, at different points in the United States, I have deduced the
velocity of the npper currents as about four times that of the surface
■wind prevailing." (Dulledn Philosoph. Soc. Washington, Dec. 16, 1871,
vol. i. p. 39.) Ami M. Peslln states in general teims : '" It is certain
according to all observations made both in mountains and in balloons,
that the force of the wind increases considerably as we ascend in the
atmosphere.' {BuUelin International de VObserv. da Paris et ds T Observ.
Phijs. Cent. Montsouris, July 7, 1872.)

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PHILOSOPHICAL SOCIETY OF WASHINGTON. 34 1

investigations at diGTerent light-stations, on our western coast of
California.

Tlie very important observation that a sound could best be heard
at an elevation when the wind is adverse (that is when it blows
Ironi the observer towards the acoustic signal,) and that after it
had even been entirely lost to the ear in such case, it might be
regained in full force by simply ascending to a suitable elevation,
— admitted apparently but one explanation, namely that the line
of successive impulse constituting a sound beam was deflected or
bent upwards by the action of the opposing wind. If — as had
already been shown to be the case sometimes, and as might there-
fore be expected generally, — the adverse wind were assumed to
be a little stronger at the elevation than at the surface such a re-
sult would at once follow. " The explanation of this phenomenon
as suggested by the hypothesis of Professor Stokes is founded on
the fact that in the case of a deep current of air the lower stratum
or that next the earth is more retarded by friction than the one
immediately above, and this again than the one above it, and so
on. The effect of this diminution of velocity as we descend toward
the earth is in the case of sound moving with the current, to carry
the upper part of the sound waves more rapidly forward than the
lower parts, thus causing them to incline toward the earth, or in
other words, to be thrown down upon the ear of the observer.
When the sound is in a contrary direction to the current, an oppo-
site effect is produced, the upper portion of the sound waves is
more retarded than the lower, which advancing more rapidly in
consequence, inclines the waves upward and directs them above
the head of the observer."*

From several observed and reported cases where the sound of a
fog-signal was exceptionally heard to a greater distance against
tlie wind than toward the direction of the wind. Professor Henry
for a while hesitated to give the hypothesis of Professor Stokes
an unqualified acceptance ; but forced as he was constantly to recur
to it as the only plausible explanation of the ordinary influence of
wind on the transmission of sound, he finally was able to satisfy
himself that even the apparent exceptions to the rule were really
in accord with it. Having more tlian once observed that when
the upper current of air, as indicated by the course of the clouds,
is in an opposite or different direction from the lower or sensible
wind, the range of audibility is most affected and favored by the
upper current, it was a natural induction to extend such a condi-
tion in imagination to other cases of abnormal behavior of sound.
A large amount of subsequent labor and attention was devoted to
the determination of this important question.

* Report of Litjht House Board for 1874, p. lOG.
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348 BULLETIN OF THE

In 1872 it was observed from on bnar'l a steamer approachini?
Portland Head station in the harbor ot Portland (Maine) that the
fog-signal which had been distinctly heard through many miles;
was lost to the ear when within two or three miles of the point,
that it continued inaudible throughout the nearer distance of a
mile or so, and that it was again heard as the station was neared.
At Whitehead light station on a small rocky island about a mile
and a half from the coast, (being some 65 miles northeast of Port-
land Head,) it was observed on board a steamer approaching the
station during a thick fog, that the signal (a 10-inch steam whistle)
though distinctly heard at the distance of six miles or more, and
with increasing distinctness as the steamer advanced, was suddenly
lost at about three miles, and was not recovered until within a
quarter of a mile from the station ; the wind at the time being ap-
proximately adverse to the sound. A six-inch steam w-histle on
board the steamer was meanwhile distinctly heard at the station
during the whole time of inaudibility of the larger ten-inch whistle,
which had also been sounded without any interruption. This re-
markable phenomenon implied a compound flexure of the sound
beams, and accorded with previous observations made at the same
points by Gen. Duane the engineer in charge of the first and second
Light-house Districts.

In 1873 observations were again made at Whitehead station,
and at Cape Elizabeth light station, both on the coast of Massa-
chusetts. At Whitehead the steam whistle was heard through a
distance of 15 miles, with a light adverse wind. At Cape Eliza-
beth, with a stronger adverse wind, the siren was heard only about
nine miles

In 1874, observations were made at Little Gull Island (off the
coast of Connecticut); at Block Island, (off the coast of Khode
Island); and at Sandy Hook (Xew Jersey). At Little Gull
Island the sound of a siren was heard against a moderate wind,
only three and a half miles. At Block Island the siren was reported
to have been heard under favoring conditions of wind through a
distance of more than 25 miles. While it was frequently heard at
Point Judith station, and the siren at the latter puint was as fre-
quently heard at Block Island, (the distance between the two points
being 17 miles,) it was shown on comparison of records, that the
two instruments had not been heard simultaneously; the wind
when favorable to the one being unfavorable to the other.

At Sandy Hook, for the purpose of making simultaneous ob-
servations in different directions, three steamers (the tenders of
different light-houses) were employed, with steam whistles specially
adjusted to the same tone and power. The latter quality having
been carefully tested by the phonometer, the three vessels steamed
out abreast on trial; and their whistles sounding in regular suc-
cession " became inaudible all very nearly at the same moment."
One of the vessels being then anchored at a distance from laud,

122

PHILOSOPHICAL SOCIETY OF WASHINGTON. 349

tlie two others were directed- in opposite courses, one witli the
wind, or eastward, tlie otiier against it, or westward. In 15
minutes the whistle of the former ceased to be heard, while that
of the latter was very distinctly heard ; the anemometer showing
a wind of about six miles per hour. About noon the vessels
changed positions, but the sound from the west continued audible
lor about three times the distance of that from the east, though
the wind hud declined to nearly a calm or to about hiilf a mile
l)er hour. In an hour and a half the wind had changed to "within
two points of iiu exactly op[)osite direction, blowing from the
indications of the anemometer at the rate of ten and a half miles
l)er hour." The vessels once more dejjarting, one with the wind,
the other against it, the sound of the whistle coming against the
wind was this time heard for the greater distance, contrary to
expectation. On the following day a number of small balloons
having been provided, a similar series of experiments to that of
the preceding day was made ; a station being selected at a greater
distance from land. On the first trial, with a light wind from the
west of about one and a quarter miles per hour as indicated by the
anemometer, a balloon was set off which continued rising and
moving eastward till lost to sight. Two of the vessels taking
opposite courses as l)efore, gave the sound in the direction of the
wind about double the duration of that coming against the slight
wind. The vessels then changed places in their opposite courses ;
the wind having subsided to a calm. " A balloon let off ascended
vertically until it attained an elevation of about 1,000 feet, when
turning east it followed the direction of the previous one. In this
case the sound of the whistle coming from the east was heard
somewhat longer than the opposite one. At the third trial made
after noon, the wind had changed nearly one-third of the circle, its
force being about five miles per hour. The vessels once more
taking their courses with the wind and against it, ''several bal-
loons set off at this time were carried by the surface wind west-
wardly until nearly lost to sight, when they were observed to turn
oast, following the direction of the wind traced in the earlier
observations." In this case the sound was heard with the wind
very slightly farther than against it. It was thus shown that the
upper current of wind had remained constant throughout the day,
while the changing surface wind was apparently a land and sea
breeze "due to the heating of the land as the day advanced:"
and the varying behavior of the sound beams was easily explained
by the varying differences of velocity in their wave fronts at dif-
ferent heights.

In 1875 Henry continued his observations at Block Island (R.
I.) and at Little Gull Island (Conn.). The southern light-house
on Block Island standing on the edge of a perpendicular cliff 152
feet above the sea level, and being itself 52 feet hi<>h (to its focal
plane), this poini was selected for making investigations on the

123

350 BULLETIN OP THE

effect of altitude in modifying unfavorable conditions of audibility.
Observers were accordingly stationed on tlie beach at the foot of
the cliff, and also on the tower 200 feet above, to record simul-
taneously the duration of the whistle signals of two steamers pro-
ceeding in opposite directions toward tiie right and the left. The
sound coming against the wind (of about seven miles per hour)
continued audible at the upper station four times longer, (^. e.,
for four times greater distance) than at the lower station. The
sound coming with the wind, was unexpectedly heard at the lower
station for a longer period than at the upper one. Another ob-
servation (with the wind about five miles per hour) gave for the
sound against the wind, rather more than twice the distance of
audibility at the upper station; and for the sound favored by the
wind, a slightly greater distance at the top than at the bottom
station. The next observation gave as before, with the adverse
wind, the advantage of more than double the distance of audibility
to tiie upper station ; meanwhile one of the observers at the foot
of the cliff, after the sound was entirely lost, managed by climbing
to a ledge about 30 feet above the beacli, to recover tiie signal
quite distinctly, and to hear it for some time. The sound coming
with the wind continued to be heard at both the higher and the
lower stations for precisely the same time, giving on this occasion
no advantage to either. Observations made on board the two
steamers while moving in opposite directions, gave for the sound
travelling with tiie wind a duration and distance more than five
times that for the sound which came against the wind. Five
similar experiments gave very similar results. The two vessels
moving in opposite courses, each at right angles to the direction
of the wind, gave a very close equality for the reciprocal dura-
tions of the sound. In the following month, similar observations
were made at Little Gnll Island, which were very accordant with
those made at the former station. As a result of plotting the
ranges of audibility in different directions from a given point,
producing a series of circular figures (more or less distorted) of
very different sizes, Henry was inclined to believe that the whole
urea of audition is less in high winds than in gentle winds. These
investigations as their author well remarks, — "though simple in
their conception have been difficult and laborious in their execu-
tion. To be of the greatest practical value they were required to
be made on the ocean under the conditions in which the results
are to be applied to tlie use of the mariner, and therefore they
could only be conducted by means of steam vessels of sufficient
jiower to withstand the force of rough seas, and at times when
these vessels could be spared from other duty. They also required
a number of intelligent assistants skilled in observation and faith-
ful in recording results."*

* Report of the Light-house Board U. S. for 1875, p. 107.

124

PHILOSOPHICAL SOCIETY OF WASHINGTON. 351

In the summer of last year, IS11, with undiminished ardor, he
conliiiued his d^servations on sound; selecting this time Portland
harbor, Monhegan Island, and Whitehead light station, on the
coast of Maine. At the latter station, the abnormal phenomenon
of a region of inaudibility near the fog-signal, and extending out-
ward for two or three miles, (beyond which distance the signal is
again very distinctly heard,) had for several years been frequently
observed. This singular eifect is noticed only in the case of a
southerly wind when the vessel is approaching the signal from
the same quarter, and consequently with the wind adverse to the
direction of the sound beams, a condition of the wind which is
the usual accompaniment of a fog. The observation showed this
intermediate "belt of silence" to be well marked on board the
steamer both on ai)proaeliing the station and on receding from it
by retracing the same line of travel. Meanwhile the intermittent
signal whistle from the steamer was distinctly heard at the station
on both the outward and homeward trips of the vessel, through-
out its course. The next set of observations was made on the
opposite side of the small island, by directing the course of the
steamer northward ; and in this case the shore signal was dis-
tinctly heard throughout the trip, while the signal from the vessel
passed through tlie " belt of silence" to the observers at the sta-
tion. The hypothesis of a local sound shadow of definite extent,
is excluded by the simple fact that the regions traversed were
entirely unobstructed, the two points of observation — movable
and stationary — being constantly in view from each other when
not obscured by fog. The hypothesis of a stationary belt of
acoustic opacity is equally excluded by the uninterrupted trans-
mission of sound through the critical region in one direction ;
and this too whichever order of observation be selected. So that
in one of the cases the powerful whistle ten inches in diameter
blown by a steam pressure of 60 pounds, failed utterly to make
itself heard, while the sound from a much feebler whistle only six
inches in diameter and blown by a steam pressure of 25 pounds,
traversed with ease and fulness the very same space. The only
hypothesis left therefore is that of diacoustic refraction; by which
the sound beam from one origin is bent and lifted over the observer,
while from an opposite origin the refraction is in a reversed direc-
tion; and such a quality in tlie moving air is referable to no other
observed condition but that of its motion, that is to the influence
of the wind. Observations were afterward made at Monhegan
Island, on some of the more normal effects of the refraction of
sound by differences of wave velocity, all fully confirming the
supposition which had been so variously and critically subjected
to examination.

The principal conclusions summed up in this last Report for
1817, are: 1st. The audibility of sound at a distance depends

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352 BULLETIN OF THE

primarily upon the pitcli, tlie intensity, and tlic quantity of tlic
sound : the most efficient pitch being neither a very high nor a
very low one, — the intensity or loudness of sound resulting from
the amplitude of the vibration, and the quantity of sound result-
ing from the mass of air simultaneously vibrating. 2nd. The
external condition of widest transmission of sound through the
air is that of stillness and perfect uniformity of density and tem-
perature throughout. 3rd. The most serious disturbance of the
audibility of sound at a distance, results from its refraction by
the wind, which as a general rule moving more freely and rapidly
above than near the earth, tends by this difference to lift the
sound-beams upward when moving against the wind, and in a
downward curve when moving with it. 4th. When the upper
current of air is adverse to the lower or sensible wind, or when-
ever from any cause the wind below has a higher velocity than
that above — in the same direction, the reverse phenomenon is
observed of sound being heard to greater distances in opposition
to the sensible wind than it is when in the direction of the surface
wind. 5th. While suitable reflectors and trumpet cones are ser-
viceable in giving prominent direction to sounds within moderate
or ordinary distances, yet from the rapid diffnsibility of the sound-
beams, such appliances are worthless for distances beyond a mile
or two. Gth. The siren has been frequently found to have its
clearest penetration through a widely extended fog, and also
through a thick snow-storm of large area. Vth. Intervening ob-
structions produce sound shadows of greater or less extent, which
however at a distance but slightly enfeeble the sound owing to
the lateral diffusion and closing in of the sound waves. 8th. The
singular phenomenon of distinct audibility of sound to a distance
with a limited intermediate region of inaudibility where no optical
obstruction exists, is due sometimes to a diffusion of upper sound-
beams which have not suffered the upward refraction; sometimes
to the lateral refraction of sound-beams or to the lateral spread
of sound from directions not affected by the upward refraction;
and very frequently to a double curvature of the refracted sound-
beams under an adverse lower wind, by reason of the wave fronts
being less retarded by the lower or surface stratum of wind than
by that a short distance above, and at still greater heights being
again less retarded, and finally accelerated by the superior favor-
ing wind.

'O

These remarkable series of acoustic investigations undertaken
after the observer had considerably exceeded his three score years,

perseveringly continued weeks at a time, and sometimes for

more than a month, — extending through a period of twelve years,
and pursued over a wide and extremely irregular range of sea-
coast, and under great variety of both topographical and meteor-
ological conditions — untiringly prosecuted by numberless sea

126

PHILOSOPHICAL SOCIETY OP WASHINGTON. 353

trips of 10, 15 and even 20 miles in sin<rle stretches, in calm, in
sunshine, in storm, with every variety of disregarded exposure,
form altogether a labor and a research — quite unequalled and uii-
approached by any siuiilar ones on record. As a result of so
great earnestness and thoroughness in the conduct of an enter-
prise of so great difficulty, Henry has advanced and enriched
our knowledge by contributions to the science of acoustics un-
questionably the most important and valuable of the century.
By persistent cross-examination of tiie bewildering anomalies of
sound propagation under wide diversities of locality and con-
dition, he has succeeded in evolving order out of apparent chaos,
— in reclaiming a new district, now subjected to the orderly reign
of recognized law, — and iu raising the plausible but long neglected
hypothesis of Stokes into the domain of a verified and fully estab-
lished theory. Only on the subject of the ocean echo had he
failed to reach a solution which entirely satisfied his judgment;"
and at the ripe age of four score years he had mapped out a
further extension of his laborious search after truth, when his
beneficent and all unselfish purposes were cut short by death.

With these great labors (a full demand upon the energies of
youthful vigor) fittingly closed the life of one whose long career
liad been dedicated to the servif'e of his race, — no less by the un-
recorded incitations and encouragements of others to the prose-
cution of original research, than by his own earnest efforts on all
convenient occasions to extend the boundaries of our knowledge.
Nor is it permitted us to indulge in vain regrets that thirty years
of such a life were seemingly so much withdrawn from his own
chosen ministry at the altar of science, to be occupied so largely
with the drudgery and the routine of merely administrative duties.
True though it be, that talents adapted to such functions are very
much more common and available than those which form the suc-
cessful interrogator of Nature, who that knows by what exertions
Smithson's wise endowment was rescued from the wasteful dissi-
jiation of heterogeneous local agencies nnd objects — by what
heroic constancy, and through what ordeals of remonstrance and

* " The question, therefore, remains to be auswered : what is the cause
of the aerial echo ? As I have stated, it must in some way be connected
witlx the horizon. The only explanation which suggests itself to me at
present is, that the spread of tlie sound wliich fills the whole atmosphere
from the zenith to the horizon with sound-waves, may continue their
curvilinear direction until they strike the surface of the water at such
an angle and direction as to be reflected back to the ear of the observer.
In this case the echo would be lieard from a perfectly flat surface of
water, and as different sound-rays wo ild reach the water at different dis-
tances and from different azimuths, they would produce the prolonged
character of the echo and its angular extent along the horizon. While
we do not advanca this hypothesis as a final solution of the question, we
shall provisionally adopt it as a means of suggesting further experiments
in regard to this perplexing question at another season." (^Report of
Light House Board, 1&77, p. 70.)

VOL. II.— 23 127

354

BULLETIN OF THE

misconception, of contumely and denunciation, tlie modest income
of tlie fund (husbanded and increased by prudent nianagemenl)
was yearly more and more witlidravvn from merely popular uses
and interests, and more and more applied to its truest and highest
purpose, the fostering of abstract research, the founding of a
pharos for the future,— the " increasing and diffusing of know-
ledge among men, "—who that knows all this, can say that Henry
was mistaken in liis devotion, or that his ripest years were wasted

in an unprofitable mission ? But in addition to this vast work,

accomplished as probably no one of his scientific compeers would
have had the fortitude and the indomitable persistence to carry
through, his personal contributions to modern science (as has
been shown) have in the meantime been neither few nor unim-
portant.

One remarkable circumstance relating to Henry's directorship
of the Smithsonian publications (which have had so wide a dis-
tribution and influence)* must not be here passed over. Having
himself amidst the absorbing occupations of his position conducted
so valuable original investigations — on the strength of building
materials, — on the best illuminants and their proper conditions,—
and especially in his last great labor on the philosophy of sound,
we should naturally expect to find them displayed in the " Smith-
sonian Contributions;" — where in interest and importance second
to none contained in that extensive and admirable series, these
memoirs would have found their fitting place, and have given
honor to the collection. But as if to avoid all semblance of a
personal motive in his resolute policy of administration, he pub-
lished nothing for himself at the expense of the Smithsonian fund ;
his numerous original productions being given to the public
through the channel of various official reports. And thus it has
occurred that his writings scattered in the different directions
which seemed to him at the time most suitable, with little thought
of any special publicity or perpetuity, have largely failed to reach
the audience which would most appreciate them. And many of
his most valuable papers — never by himself collected — must be
searched for in unsuggestive volumes of Agricultural or Light-
House Board Reports. f

* "The number of copies of the Smithsonian Contributions distributed,
is greater than that of tlie Transactions of any scientific or literaiy
society ; and therefore the Institution offers the best medium to be found
for diffusing a knowledge of scientific discoveries." (Smithsonian Report
for 1851, p. 202.)

t Many valuable communications made to the Airerican Association,
to the National Academy of Sciences, to the Washington Philosophical
Society, and to other bodies, from rough notes, which their author was
prevented from writing fairly out, by the unceasing pressure of liis mul-
titudinous oflicial and public duties, have unfortunately been published
only by title.

128

PHILOSOPHICAL SOCIETY OF WASHINGTON. 355

For him it seemed enough tliat what was once establisiied,
would not be willingly let die ; that the medium or the occasion
of communication was of comparatively little consequence, if but
a new fact or principle were thrown into proper currency, and
duly accepted as part of the world's wealth : and beyond all ordi-
nary men he seemed to feel the insigniticance of personal fame as
compared with the infinite value of truth. For such a man the
most appropriate monument would be a full collection of his
writings, produced in a worthy and appropriate style of publica-
tion.

PERSONALITY AND CHARACTER.

Of Henry's personal appearance, it is sufficient to say, that his
figure, above the medium height, was finely proportioned ; that
his mien and movement were dignified and imposing ; and that on
whatever occasion called upon to address an assembly,

"With grave asppct he rose, and in his rising seemed
A pillar of state: deep on his front engraven
Deliberation sat, and public care."

His head and features were of massive mould ; though from the
perfect proportion of his form, not too conspicuously so. His
expansive brow was crowned with an abundant flow of whitened
hair; his lower face always smoothly shaven expressed a mingled
gentleness and firmness ; and his countenance of manly symmetry
was in all its varying moods, a pleasant study of the mellowing,
moulding impress of long years of generous feeling, and a worthy
exponent of the fine and thoughtful spirit within : wearing in re-
pose a certain pensive but benignant majesty, in the abstraction
of study a semblance of constrained severity, in the relaxation of
friendly intercourse a genial frank and winning grace of expres-
sion. Like his intimate personal friend Agassiz, he seemed to
stand and to move among men as the very embodiment of unfail-
ing vigorous health and physical strength, and only a year ago, he
walked with as erect and elastic a carriage, — with as firm and
sprightly a step, as any one here present.

It is difficult to attempt even a sketch of Henry's intellectual
character, without allusion to his moral attributes; — so constantly
did the latter dominate the former. It may be said that the most
characteristic feature of his varied activities was earnestness, and
this as usual was the offspring — as much of a moral as of a mental
purpose.

His mind was eminently logical ; and this rational power was
exhibited in every department of his theoretical or his practical
pursuits. He never showed or felt uneasiness at necessary deduc-
tive consequences, if the premises were well considered or appeared
to be well founded. If presented with the problem of an untried

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case, — while avowing the necessity of reserve in predicting results,
he seemed to have an almost intuitive appreheusion of the opera-
tion of natural law. If confronted with an unfamiliar phenomenon,
whether in the experience of others, or in his own observations,
his imagination was fertile in the susTgestion of test conditions for
eliminating varying influences. While few have ever held tho
function of hypothesis in higher estimation as an instrument of
research, no one ever held hypothesis in more complete sub-
jection.

As a lecturer and instructor, he was always most successful.
Free from all self-consciousness, — without attempting oratorical
display, his expositions — in simple, direct, and conversational
language, were so lucid, satisfying, and convincing, that they
enlisted from the start and secured to the close, the attentive
interest of his auditors.

In his sympathy with the pursuits of the rising generation of
physicists was ever manifested a disposition to frequent consulta-
tion and interchange of views with them ; as if (aware of the usual
tendency to mental ossification with advancing years,) he thus
sought by familiar association to drink at the fountain of perennial
youth. And surely no one was ever more successful in retaining
ife's coveted greenness in age ; — not more in the geniality of his
.'iffections and in his undimnud faith, hope, and charity, for man-
kind,— than in his intellectual freedom from undue prejudices, and
in his readiness calmly to discuss or adopt new theories.

And tills leads to the reflection that in the seeming contrasts of
his nature were combined qualities which formed in him a resultant
of character and of temperanunt as rare as admirable With this
trreat mobility of aptitude and of circumspection, this adaptability
of mental altitude, he yet possessed an unusual firmness of resolu-
tion. With a manly sturdiness of conviction he presented an un-
varying equability of temper and of toleration ; and with perfect
candor as perfect a courtesy. With a characteristic dignity of
figure of presence and of deportment, he ]ireserved an entire free-
dom from any shade of arrogance. With a warm and active
charity, he still displayed a shrewd perception of character ; and
while ever responsive to the appeals of real distress, his insight
into human nature protected him from being often deceived by the
wiles of the designing. Intolerant of charlatanism and imposture,
he was capable of exhibiting a wonderful patience with the tedium
of honest ignorance. Possessing in earlier life a natural quick-
ness of tem[)er, and always a high degree of native sensibility, his
perfect self-control led the casual acquaintance to regard him as
reserved and unimpressible. Of him it may be truly said iu
simple and oft-quoted words :

" His life was gentle ; and the elements

So mixed in liim, that Nature mipht stand np

And say to all the world — This was a jia>' !"

PHILOSOPHICAL SOCIETY OF -WASHINaXOX. iJ5t

■With all his broad humanity, he possessed but little of what is
known as " humor." He could more heartily enjoy the ludicrous
us drolly narrated by its appreciative victims, than when sarcasti-
cally recited at the expense of another. The sparkle of wit he
i'ully appreciated ])rovided it were free from coarseness and from
personal satire. From the subordination of his sense of humor to
his native instinct of sincerity, he had no approbation — or indeed
tolerance of " practical jokes," holdinjj^ that the shock to the feel-
ings or to the confidence of the dupe, is fur too high a price for the
momentary hilarity enjoyed by the thoughtless at a farcical situa-
tion. Newspaper hoaxes — literary or scientific, in like manner
received his stern reprobation, as uncompensated injuries to
popular trust, and to tlie cause of jiopular enlightenment.

Strong in his unerring sense of justice and of right, he allowed
no prospects of personal advantage to influence his judgment in
action, in decision, or in opinion. He never availed himself of
the opportunities offered by his position, of reaping gain from
profitable suggestions or favorable awards : and he never willingly
inflicted an injury even on the feelings of the humblest. This
was characteristically shown in the pains taken to convince the
judgment of those against whose visionary projects he was so often
called upon to report in the public interests of the Smithsonian
Institution, of the Light-house service, and of the General Gov-
ernment : — often expending an amount of valuable time and of
patience which few so situated would have accorded, or could
have well afforded. And 3'et on the other hand when himself
the subject of injustice, misconstruction, or abuse, he never suffered
himself to be provoked into a controversy ; — as if holding life too
serious, time too precious, to be wasted in mere disputation
Least of all did he ever think of resorting to retaliatory conduct
or to the expression of opprobrious sentiments. He calmly put,
aside disturbing elements, and seemed endowed with the power of
excluding from his mental vision all irritating incidents. In that
benignant breast there harbored no resentments.

To those who knew the man, — to those who have enjoyed the
charm of his more intimate society, and felt the magnetism of his
cheery presence, how poor and insufficient must appear these dis-
jointed outlines of that mental, moral, and spiritual nature, which
always and at every point was so much larger than it seemed.

Less than ayea^-ago, (ontheeveningof November 24th, 18T7,) he
delivered in this place before this Society his annual address, shortly
after his re-election as its President; — an address which as we be-
held the remarkable fulness and freshness of the speaker's mental
and bodily powers, — we little thought was in reality his vale-
dictory, in it he concisely yet lucidly portrayed for the stimula-
tion of more youthful physicists, the processes and the qualities
necessary for success in original research ; — the awakened attentioa

131

358 BULLETIN OF THE

to "the seeds of great discoreries constantly floating around us,"
• — the careful observation, the clear perception of the actual facts
uncolored as much as possible by a priori conceptions or expec-
tations,— the faculty of persevering watchfulness, and the judg-
ment to eliminate (with all due caution) the conditions which are
accidental, — the importance of a provisional hypothesis, — the
conscientious and impartial testing of such by every expedient that
ingenuity may suggest, — the lessons taught by failure, — the firm
holding of tlie additional facts thus gleaned, though adverse and
disappointing, — the diligent pondering, and the logical applica-
tion of deductive consequences, to be again examined until as the
reward of patient solicitation, the answer of nature is at last re-
vealed.

"The investigator now feels amply rewarded for all his toil,
and is conscious of the pleasure of the self-appreciation which
flows from having been initiated into the secrets of nature, and
allowed the place not merely of an humble worshipper in the ves-
tibule of the temple of science, but an officiating priest at the
altar. In this sketch which I have given of a successful investi-
gation, it will be observed that several faculties of the mind are
called into operation. First, the imagination, which calls forth
the forms of things unseen and gives them a local habitation,
must be active in presenting to the mind's eye a definite concep-
tion of the modes of operation of the forces in nature sufficient to
produce the phenomena in question. Second, the logical power
must be trained in order to deduce from the assumed premises
the conclusions necessary to test the truth of the assumption in
the form of aa experiment, and again the ingenuity must be taxed
to invent the experiment or to bring about the arrangement of
apparatus adapted to test the conclusions. These faculties of
mind may all be much improved and strengthened by practice.
The most important requisite, however, to scientific investigations
of this character, is a mind well stored with clear conceptions of
scientific generalizations, and possessed of sagacity in tracing
analogies and devising hypotheses. Without the use of hypotlieses
or antecedent probabilities, as a general rule no extended series
of investigations can be made as to the approximate cause of casual
phenomena. They require to be used however with great care,
lest they become false guides whicli lead to error rather tlian to
truth."* Who that listened could f-.iil to see that the speaker
was unconsciously giving us precious glimpses into his own expe-
rience?

Less than two weeks after this, he sufiFered at New York a tem-
porary numbness in his hands, which he feared might threaten a
paralysis ; but a subsequent swelling of his feet and hands revealed

* Bulletin Phil. Soc. Washington, Nov. 24, 1877, vol. ii. p. 166.

132

PHILOSOPHICAL SOCIETY OF WASHINGTON. 359

to his physician the nature of his inward disease as a nephritis,
which had been insidiously assailing hira before it was suspected,
and had doubtless been aggravated by his unremitting scientific
labors continued as usual through his last summer vacation. Only
a month before he died, he thus described the commencement of his
malady: "After an almost uninterrupted period of excellent health
for fifty years, I awoke on the 6th of December at my office in the
Light-house Depot in Staten Island, finding my right hand in a
paralytic condition. This was at first referred by the medical
adviser to an affection of the brain, but as the paralysis subsided in
a considerable degree in the course of two days, this conclusion was
doubted, and on a thorough examination through the eye, and by
means of auscultation, and chemical analysis. Dr. Weir Mitchell
and Dr. J. J. Woodward pronounced the disease an affection of
the kidneys."*

Aware that his illness was fatal, he yet felt lulled by that strange
flattery of disease when unattended with a painful wasting, into the
thought that he might probably survive the approaching warmer
weather; and fully prepared for death, with the sense of life still
strong within hira, he planned what might yet be accomplished.

But with occasional alternations of more favorable symptoms,
with the uraemia steadily increasing, his strength slowly declined :
and as he lay at noon of the 13th of last May, [1878,] with grow-
ing difficulty of breathing — surrounded by loving and anguished
hearts — his last feeble utterance was an inquiry which way the
wind came. With intellect clear and unimpaired, calmly that pure
and all unselfish spirit passed away — leaving a void none the less
real, none the less felt, that the deceased had reached a good old
age, and had worthily accomplished his allotted work.

Great as is the loss we have sustained of " guide, philosopher,
and friend," we have yet the mournful satisfaction of reflecting that
his influence, powerful as it always has been for good, still survives
— in his works, his high example, and his unclouded memory ; —
that our community, our country, the world itself, has been bene-
fited by his existence here ; and that as time rolls on, its course
will be marked by increasing circles of appreciation, reverence,
and gratitude, for the teachings of his high and noble life.

* Opening Address, written for the meeting of the National Academy of
Sciences, April IGth, 1878. {Proceed. Nat. Acad. Sci , vol. i. part 2, p.
127.)

133

360 BULLETIN OF THE

LIST OF SCIENTIFIC PAPERS ; BY JOSEPH HENRY.

1825. On the production of cold by the rarefaction of Air: iaccompanied

with Experiments. (Presented Mar. 2.) Abstract, Trans.

Albany Institute, vol. i. part ii. p. 36.
1827. On some Modifications of the Electro-magnetic Apparatus. (Read

Oct. 10.) Trans. Albany Inst. vol. i. pp. 22-24.
1829. Topographical Sketch of the State of New York ; designed chiefly

to show the General Elevations and Depressions of its Surface.

(Read Oct. 28.) Trans. Albany Inst. vol. i. pp. 87-112.
1829. First Abstract of Meteorological Records of the State of New

York, for 1828. (In conjunction with Dr. T, Romeyn Beck.)

A nnual Report of Regents of University, to the Legislature

of New York.— Albany, 1829.

1829. On the Mean Temperature of Twenty-seven different Places in the

State of New York, for 1828. (In conjunction with Dr. T.
Romeyn Beck.) Brewster's Edinburgh Jour, Science, Oct.
1828, vol. i. pp. 249-259.

1830. Second Abstract of Meteorological Records of the State of New

York for 1829. (In conjunction with Dr. T. Romeyn Beck.)
Annual Report of Regents of University, to the Legislature
of New York.— Albany, 1830.
1331. On the Application of the Principle of the Galvanic Multiplier to
Electro-magnetic Apparatus, and also to the development of
great Magnetic power in soft iron, with small Galvanic Elements.
Silliman's American Jour. Science, Jan. 1831, vol. xix. pp.
400-408.

1831. Tabular Statement of the Latitudes, Longitudes, and Elevations,

of 42 INIeteorological Stations in New York. Aiinual Report
Regents of University to Legislature N. Y. 1831.

1831. Third Abstract of Meteorological Records of State of New York
for 1830. (In conjunction with Dr. T. Romeyn Beck.) Annual
Report of Regents of University, to the Legislature of Now
York.— Albany, 1831.

1831. An Account of a large Electro-magnet, made for the Laboratory
of Yale College. (In conjunction with Dr. Ten Eyck.) Silli-
man's Am. Jour. Sci. April, 1831, vol. xx. pp. 201-203.

1831. On a Reciprocating Motion produced by Magnetic attraction and

repulsion. Silliman's Am. Jour. Sci. July, 1831, vol. xx. pp.
340-343. Sturgeon's Annals of Electricity, etc. vol. iii. pp.
430-432.

1832. On a Disturbance of the Earth's Magnetism in connection with

the appearance of an Aurora as observed at Albany on the
19th of April, 1831. (Communicated to the Albany Institute,
Jan. 26, 1832.) Report of Regents of University, to the Legis-
lature of New York. — Albany, 1832. Silliman's Am. Jour. Sci.
July, 1832, vol. xxii. pp. 143-155.
1832. Fourth Abstract of Meteorological Records of the State of New
York for 1831. (In conjunction with Dr. T. Romeyn Beck.)
Ajimcal Report of Regeiits of University, to the Legislature
of New York.— Albany, 1831.

134

PHILOSOPHICAL SOCIETY OF WASHINGTOX. 361

1832. On the Production of Currents and Spo,rks of Electricity from
Magnetism, Sillimau's A7n. Jour. Sci. July, 1832, vol. xxii.
pp. 403-408.

1832. On the effect of a long and helical wire in increasing the intensity

of a galvanic current from a single element. Silliman's Am.
Jour. Set. July, 1832, vol. xxii. p. 408. Becquerel's Traits
experimental de l'Electricit6, etc. 1837, vol. v. pp. 231, 232.

1833. Fifth Abstract of Meteorological Records of the State of New

York, for 1832. (In conjunction with Dr. T. Romeyn Beck.)
Annual Report of Regents of University, to the Legislature
of New York.— Albany, 1833.

1835. Contributions to Electricity and Magnetism. No. I. Description
of a Galvanic Battery for producing Electricity of different in-
tensities. (Read Jan. 14.) Transactions Am. Philosopli. So-
ciety, vol. V. pp. 217-222. Sturgeon's Annals of Electricity,
etc. vol. i. pp. 277-281.

1835. Contributions to Electricity and Magnetism. No. II. On the
influence of a Spiral Conductor in increasing the intensity of
Electricity from a Galvanic arrangement of a single Pair, etc.
(Read Feb. 6.) Trans. Amer. Phil. Soc. vol. v. pp. 223-232.
Sturgeon's Annals of Electricity, etc. vol. i. pp. 282-290.
Taylor's Scientific Memoirs, vol. i. pp. 540-547.

1835. Facts in reference to the Spark, etc. from a long Conductor uniting
the poles of a Galvanic Battery. Journal of Franklin Institute,
Mar. 1835, vol. xv. pp. 169, 170. Silliman's Am. Jour. Sci.
July, 1835, vol. xxviii. pp. 327-331.

1837. A Notice of Electrical Researches, particularly in regard to the

" lateral discharge." (Read before the British Association at
Liverpool, Sept. 1837.) Report Brit. Assoc. 1837. Part II.
pp. 22-24. Silliman's Am. Jour. Sci. April, 1838, vol. xxxiv.
pp. 16-19.

1838. A Letter on the production directly from ordinary Electricity of

Currents by Induction, analogous to those obtained from Galvan-
ism. (Read to Philosoph. Society, May 4.) Proceedings Am.
Phil. Soc. vol. i. p. 14.

1838. Contributions to Electricity and Magnetism. No. III. On Electro-

dynamic Induction. (Read Nov. 2.) Trans. Am. Phil. Soc.
vol. vi. pp. 303-338. Silliman's Am. Jour. Sci. Jan. 1840, vol.
xxxviii. pp. 209-243. Sturgeon's Aiinals of Electricity, etc.
vol. iv. pp. 281-310. L. E. D. Phil. Mag. Mar. 1840, vol.
xvi. pp. 200-210: pp. 254-265: pp. 551-562. Becquerel's
T^-aitd experimental de V Electricity, etc. vol. v. pp. 87-107.
Annales de Chimie et de Physique, Dec. 1841, 3d series: vol.
iii. pp. 394-407. Poggendorff's An7ialen der Physik und
Cliemie. Supplemental vol. i. (N'ach Baud li.) 1842, pp. 282-
312.

1839. A novel phenomenon of Capillary action : the transmission of ]\Ier-

cury through Lead. (Read Mar. 15.) Proceedings Am. Phil.
Soc. vol. i. pp. 82, 83. Silliman's Am. Jour. Sci. Jan. 1839, vol.
xxxviii. pp. 180, 181. Bihlioth. Universelle, vol. xxix. pp. 175,
176. Liebig's Annalen der Chemie, etc. vol. xl. pp. 182, 183.
1839. A Ijett(5r on two distinct kinds of dynamic Induction by a Gal-
vanic current. (Read to Phil. Soc. Oct. 18.) Proceedings Am'
P/al aS'oc. vol. i. pp. 134-136.

135

362 BULLETIN OF THE

1839. Observations of Meteors made Nov. 25, 1835, simultaneously at

Princeton and at Philadelphia, for determining their difference
of Longitude. (In conjunction with Professors A. D. Bache, S.
Alexander, and J. P. Espy.) Proceedings Am. Phil. Soc. Dec.
21, vol. 1. pp. 162, 163. Silliman's Am. Jour. Sci. Oct. 1840,
vol. xxxix. pp. 372, 373.

1840. Contributions to Electricity and Magnetism. No. IV. On Electro-

dynamic Induction. (Read June 19.) Trans. Am. Phil. Soc.

vol. viii. pp. 1-18. Silliman's Am. Jour. Sci. April, 1841, vol.

xli. pp. 117-152. Sturgeon's Annals Electricity, etc. vol. vii.

pp. 21-56. L. E. D. Phil. Mag. June, 1841, vol. xviii. pp.

482-514. Annates de Chim. et Phys. Dec. 1841, 3d ser. vol.

iii. pp. 407-436. Poggendorff' s Annal. der Phys. und Chem.

1841, vol. liv. pp. 84-97.
1840. Contributions to Electricity and Magnetism. No. IV, — continued.

Theoretical Considerations relating to Electro-dynamic Induc-
tion. (Read Nov. 20.) Tran.s. Am. Phil. Soc. vol. viii. pp.

18-35.
1840. On the production of a reciprocating motion by the repulsion in

the consecutive parts of a conductor through which a galvanic

current is passing. (Read Nov. 20.) Proceedings Am. Phil.

Soc. vol. i. p. 301.

1840. Electricity from heated Water. (Read Dec. 18.) Proceedings

Am. Phil. Soc. vol. i. pp. 322-324.

1841. Description of a simple and inexpensive form of Heliostat. (Read

Sept. 17.) Proceedings Am. Phil. Soc. vol. ii. p. 97.

1841. Observations on the effects of a Thunderstorm which visited

Princeton on the evening of the 14th of July, 1841. (Read
Nov. 5.) Proceedings Am. Phil. Soc. vol. ii. pp. 111-116.

1842. R6sum6 des Recherches faits sur les Courants d'Induction,

Archives de I' Electricity, 1842, vol. ii. pp. 348-392.

1842. Contributions to Electricity and and Magnetism. No. V. On

Electro-dynamic Induction : and on the oscillatory discharge.
(Read June 17.) Proceedings Am. Phil. Soc. vol. ii. pp. 193-
196.

1843. On Phosphorogenic Emanation. (Read May 26.) Proceedings

Am. Phil. Soc. vol. iii. pp. 38-44. Walker's Electrical Maga-
zine, 1845, vol. i. pp. 444-450.

1843. On a new Method of determining the Velocity of Projectiles.
(Read May 30.) Proceedings Am. Phil. Soc. vol. iii. pp. 165-
167. Walker's Electrical Magazine, 1845, vol. i. pp. 250-352.

1843. Nouvelles Experiences sur I'lnduction d6veloppee par I'ElectricitS
ordinaire. ('IVansIated.) Archives de I'Electricite, 1843, vol.
iii. pp. 484-488.

1843. On the application of Melloni's thermo-electric apparatus to Me-
teorological purposes. (Presented orally Nov. 3.) Proceedings
Am. Phil. Soc. vol. iv. p. 22.

1843. Theory of the discharge of the Leyden jar. (Presented Nov. 3.)

Proceedings Am. Phil. Soc. vol. iv. pp. 22, 23.

1844. On the Cohesion of Liquids. (Read April 5.) Procedings Am.

Phil. Soc. vol. iv. pp. 56, 57. Silliman's Am. Jour. Sci. Oct.
1844. vol. xlviii. pp. 215, 216.
1844. On the Cohesion of Liquids, — continued. (Read May 17.) Pro-
ceedings Am. Phil. Soc. vol. iv. pp. 84, 85. Silliman's Am.

136

PHILOSOPHICAL SOCIETY OF WASHINGTON. 363

Jour. Set. Oct. 1844. vol. xlviii. pp. 216, 217. L. E. D. Phil.
Mag. June, 1845, vol. xxxvi. pp. 541-543.
1844. Syllabus of Lectures on Physics. Princeton, 8vo. 1844. Repub-
lished in part in S^nithsonian Report, 1856, pp. 187-220.

1844. Classification and Sources of Mechanical Power. (Read Dec. 20.)

Proceedings Am. Phil. Soc. vol. iv. pp. 127-129.

1845. On the Coast Survey. Princeton Review, April, 1845, vol. xvii.

pp. 321-344.
1845. On the relative Radiation of Heat by the Solar Spots. (Read

June 20.) Proceedings Am. Phil. Soc. vol. iv. pp. 173-176.

Brief Abstract in Report Brit. Assoc. 1845, Part II. p. 6.

Walker's Electrical Magazine, 1846, vol. ii. pp. 321-324.

Froriep's Neue Notizen, etc., No. 826, 1846, vol. xxxviii. col.

179-182. PoggendorfF's Aimalen der Physik und Chemie,

1846, vol. Ixviii. pp. 102-104.
1845. On the Capillarity of Metals. (Read June 20.) Proceedings

Am. Phil. Soc. vol. iv. pp. 176-178. Froriep's Neue Notizen,

etc., No. 825, 1846, vol. xxxviii. col. 167-169. Poggendorff's

Annalen der Physik und Chemie. 2d supplemental vol. (Nach

Band Ixxii.) 1848, pp. 358-361.
1845. On the Protection of Buildings from Lightning. (Read June 20.)

Proceedings Am. Phil. Soc. vol. iv. p. 179. Silliman's Am.

Jour. Sci. 1846, vol. ii. pp. 405, 406. Walker's Electrical

Magazine, 1846, vol. ii. pp. 324-326. Froriep's Neue Notizen,

etc.. No. 823, 1846, vol. xxxviii. col. 133, 134.
1845. An account of peculiar effects on a house struck by Lightning.

(Read June 20.) Proceedings Am. Phil. Soc. vol. iv. p. 180.
1845. On Color Blindness. Princeton Review, July, 1845, vol. xvii. pp.

483-489.

1845. On the discharge of Electricity throngh a long wire, etc. (Read

Nov. 7.) Proceedings Am. Phil. Soc. vol. iv. pp. 208, 209.

1846. Repetition of Faraday's Experiment on the Polarization of Liquids

under the influence of a galvanic current. (Read Jan. 16.)
Proceedings Am. Phil. Soc. vol. iv. pp. 229, 230.

1846. Extrait d'une Lettre k M. de la Rive, sur les Tel^graphes Elec-
triques daus les Etats-Unis de I'Amerique. Bihlioth. Univer-
selle. Archives, 1846, vol. ii. p. 178.

1846. Report on the action of Electricity on the Telegraph Wires : and
Telegraph-poles struck by Lightning. (Read June 19.) Pro-
ceedings Am. Phil. Soc. vol. iv. pp. 260-268. Silliman's Am.
Jour. Sci. 1847, vol. iii. pp. 25-32. L. E. D. Phil. Mag. 1847,
vol. XXX. pp. 186-194. Agricultural Report, Commr. Pats.
1859, pp. 509-511.

1846. On the ball supported by a water jet. (Read Oct. 16.) Proceed-
ings Am. Phil. Soc. vol. iv. p. 285.

1846. On the corpuscular hypothesis of the constitution of Matter. (Read
Nov. 6.) Proceedings Am. Phil. Soc. vol. iv. pp. 287-290.

1846. On the Height of Aurorae. (Read Dec. 3.) Proceedings Am.

Phil. Soc. vol. iv. p. 370.

1847. Programmeof Organization of the Smithsonian Institution. (Pre-

sented to the Board of Regents, Dec. 8, 1847.) Smithsonian
Report, 1847, pp. 120-132.
1847. Article on " Magnetism" for the Encyclopaedia Americana. En-
cycl. Amer. 1847, vol. xiv. pp. 412-426.

137

364 BULLETIN OF THE

1848. On Heat. — A Thermal Telescope. Silliman's Am Jour. Set. Jan.
1848, vol. V. pp. 113. 114.

1848. Explanations and Illustrations of the Plan of the Smithsonian

Institution. Silliman's Am. Jour. Set. Nov. 1848, vol. vi. pp.
305-317.

1849. On the Radiation of Heat. (Read Oct. 19.) Proceedings Am.

Phil. Soc. vol. V. p. 108.

1850. Analysis of the dynamic phenomena of the Leyden jar. Proceed-

ings Amer. Association. Aug. 1850, pp. 377. 378.

1851. On the Limit of Perceptibility of a direct and reflected Sound.

Proceedings Amer. Association, May, 1851, pp. 42, 43.
1851. On the Theory of the so-called Imponderables. Proceedings
Amer. Association. Aug. 1851, pp. 84-91.

1853. Address before the Metropolitan Mechanics' Institute, Washing-

ton. (Delivered March 19.) 8vo. Washington, 1853, pp. 19.

1854. Meteorological Tables of mean diurnal variations, etc. prepared

as an Appendix to INIr. Russell's Lectures on Meteorology.
Smithsonian Report for 1854, pp. 215-223.

1854. Thoughts on Education ; an Introductory Discourse before the

Association for Advancement of Education. (Delivered Dec.
28.) Proceedings Assoc. Adv. Education, 4th Session, 1854,
pp. 17-31.

1855. On the mode of Testing Building Materials, etc. Proceedings

Am. Assoc. Aug. 1855, pp. 102-112. Silliman's Am. Jour.
Sci. July, 1856, vol. xxii. pp. 30-38; Smithsonian Report,
1856, pp. 303-310.

1855. On the effect of mingling Radiating Substances with Combustible
Materials : (or incombustible bodies with fuel). Proceedings
Am. Assoc. Aug. 1855, pp. 112-116.

1855. -Account of Experiments on the alleged spontaneous separation of
Alcohol and Water. Proceed. Am. Assoc, Aug. 1855, pp.
140-144.

1855. On the Induction of Electrical Currents. (Read Sept. 11.) Pro-
ceedings Am. Academy of Arts, etc. vol. iii. p. 198.

1855. Note on the Gyroscope. Appendix to Lecture by Prof. E. S.
Snell. Smithsonian Report, 1855. p. 190.

1855. Remarks on Rain-fall at varying elevations. Smithsonian Re-
port, 1855, pp. 213, 214.

1855. Directions for Meteorological Observations. (In conjunction with
Prof. A. Guyot.) Smithsonian Report, 1855, pp. 215-244.

1855. Circular of Inquiries relative to Earthquakes. Smithsonian Re-
port, 1855, p. 245.

1855. Instructions for Observations of the Aurora. Smithsonian Re-
port, 1855, pp. 247-2.50.

1855. On Green's Standard Barometer for the Sm. Institution. Smith-
sonian Report, 1855, pp. 251-258.
1855. Circular of Instructions on Registering the periodical phenomena
of animal and vegetable life. Smithsonian Report, 1855, pp.
259-263.

1855. Meteorology in its connection with Agriculture. Part I. Agri-

cidtural Report of Commr. Pats. 1855, pp. 357-394. _

1856. On Acoustics applied to Public Buildings. Proceedings Am.

Assoc. Aug. 1856, pp. 119-135. Smithsonian Report, 1856,
pp. 221-234. Canadian Journal, 1857, vol. ii. pp. 130-140.

138

PHILOSOPHICAL SOCIETY OF WASHINGTON. 365

1856. Account of a large Sulphuric-acid Barometer in the Hall of the
Smithsonian Institution Building. Proceedings Am. Assoc.
Aug. 1856, pp. 135-138.

1856. Meteorology in its connection with Agriculture, Part. II. Gene-

ral Atmospheric Conditions. Agricultural Report of Comnir.
Pats. 1856, pp. 455-492.

1857. Communication to the Board of Eegents of the Smithsonian In-

stitution, relative to a publication by Prof. Morse. Smithsonian
Report, 1857, pp. 85-88.

1857. Meteorology in its connection with Agriculture, Part III. Ter-
restrial Physics, and Temperature. Agricultural Report of
Commr. Pats. 1857, pp. 419-506.

1858 Meteorology in its connection with Agriculture, Part IV. At-
mospheric Vapor, and Currents. Agricultural Report of
Commr. Pats. 1858, pp. 429-493.

1859. On Meteorology. Canadian Naturalist and Geologist, Aug.
1859, vol. iv. pp. 289-291.

1859. Application of the Telegraph to the Prediction of Changes of the
Weather. (Read Aug. 9.) Proceedings Am. Academy of
Arts, etc. vol. iv. pp. 271-275.

1859. Meteorology in its connection with Agriculture, Part V. Atmo-
spheric Electricity. Agricidtural Report of Commr. Pats.

1859, pp. 461-509.

1859. On the Protection of Buildings from the effects of Lightning.

Agricult. Report, Com. Pat. 1859, pp. 511-524.

1860. On the Conservation of Force. 'ti'iWima.W?, Am. Jour. Sci. 3xi\y

1860, vol. XXX. pp. 32-41.

1860. Circular to Officers of Hudson's Bay Company (April 20). Smith-
sonian Miscell. Collections, No. 137, vol. viii. pp. 1-6.

1860. Description of Smithsonian Anemometer. Smithsonian Repi rt,

1860, pp. 414-416.

1861. Letter on Aeronautics to Mr. T. S. C. Lowe. (March IL)

Smithsonian Report, 1860, pp. 118, 119.
1861. Article on " Magnetism" for the American Encyclopaedia. Edited

by Ripley and Dana. Am. Encycl. 1861, vol. xi. pp. 61-63.
1861. Article on " Meteorology" for the American Encyclopisdia. Edited

by Ripley and Dana. Am. Encycl. 1861, vol. xi. pp. 414-420.
] 862. Report of the Light House Board on the proposed Transfer of the

Lights to the Navy Department. Exec. Docts. 37th Cong. 2d

Sess. Senate, Mis. Doc. No. 61, pp. 2-18.

1863. Introduction to Memoir by Prof. J. Plateau. On the Figures of

Equilibrium of a Liquid Mass, etc. Smithsonian Report,
1863, pp. 207, 208.

1864. On Materials for Combustion in Lamps of Light-Houses. (Read

Jan. 12, before the National Academy of Sciences.) [Not pub-
lished in Proceedings.]

1865. Report relative to the Fire at the Smithsonian Institution, occur-

ring Jan. 24th, 1865. (In conjunction with Mayor Richard
Wallach.) Presented to the Regents February, 1865. Smith-
sonian Report, 1864, pp. 117-120.

1865. Queries relative to Tornadoes : directions to observers. Smith-
sonian Miscell. Collections, No. 190, vol. x. pp. 1-4.

1865. Remarks on the Meteorology of the United States. Smithsonian
Report, 1865, pp. 50-59.

139

366 BULLETIN OF THE

1865. Remarks on Yentilation : especially with reference to the U. S.

Capitol. Smithsonian Report, 1865, pp. 67-69.

1866. Report on the Warming and Ventilating of the U. S. Capitol.

(May 4.) Exec. Doc. No. 100. H. of Rep. 39th Cong. 1st
Sess. pp. 4-6.

1866. Report of Building Committee on Repairs to Sm. Institution from
Fire. (In conjunction with Genl. Richard Delafield, and Mayor
Richard Wallach.) Presented to Regents April 28. Smith-
sonian Report, 1865, pp. 111-114.

1866. On the aboriginal Migration of the American races. Appendix
to paper by F. Von Hellwald. Smithsonian Report, 1866, pp.
344, 345.

1866. Remarks on Vitality. Smithsonian Report, 1866, pp. 386-388.

1866. Meteorological Notes. To Correspondents. Smithsonian Report,
1866, pp. 403-412.

1866. Investigations in regard to Sound. (Read Aug. 10, before the

National Academy of Sciences.) [Not published in Proceed-
ings.]

1867. Circular relating to Collections in Archaeology and Ethnology.

(Jan. 15.) Smithsonian Miscell. Collections, No. 205, vol.
viii. pp. 1, 2.

1867. Circular relative to Exchanges. (May 16.) Smithsonian Re-
port, 1867, p. 71.

1867. Suggestions relative to Objects of Scientific Investigation in
Russian America. (May 27.) Smithsonian Miscell. Collec-
tions, No. 207, vol. viii. pp. 1-7.

1867. Notice of Peltier. Smithsonian Report, 1867, p. 158.

1867. Notes on Atmospheric Electricity. To Correspondents. Smith-
sonian Report, 1867, pp. 320-823.

1867. On the Penetration of Sound. (Read Jan. 24, before the National

Academy of Sciences.) [Not published in Proceedings.]

1868. Appendix to a Notice of Schcenbeia. Smithsonian Report,

1868, pp. 189-192.

1868. On the Rain-fall of the United States. (Read Aug. 25, before

the National Academy of Sciences.) [Not published in Pro-
ceedings.]

1869. Memoir of Alexander Dallas Bache. (Read April 16.) Biograph-

ical Memoirs of Nat. Acad. Sci. vol. i. pp. 181-212. Smith-
sonian Report, 1870, pp. 91-116.

1870. Letter. On a Physical Observatory. (Dec. 29.) Smithsonian

Report, 1870, pp. 141-144.

1871. Observations on the Rain-fall of the United States. Proceedings

California Academy of Sciences, vol. iv. p. 185.
1871. Instructions for Observations of Thunder-Storms. Smithsonian

Miscell. Collections, No. 235, vol. x. p. 1.
1871. Circular relative to Heights. For a topographic chart of N.

America. Smithsonian Miscell. Collections, No. 236, vol. x.

P- 1-

1871. Directions for constructing Lightning-Rods. Smithsonian. Mis-
cell. Collections, No. 237, vol. x. pp. 1-3. Silliman's Am. Jour.
Sci. Nov. 1871, vol. ii. pp. 344-346.

1871. Letter to Capt. C. F. Hall, in regard to the Scientific Operations
of the Expedition toward the North Pole. (June 9.) Smith-
sonian Report, 1871, pp. 364-366.

140

PHILOSOPHICAL SOCIETY OF WASHINGTON. 367

1871. Suggestions as to Meteorological Observations ; during the Expe-
dition toward the North Pole. Smithsonian Report, 1871, pp.
372-379.

1871. Meteorological Notes and Remarks. Smithsonian Report, 1871,
pp. 4.52, 45.5. 456, 459, 461.

1871. Effect of the Moon ou the Weather. Smithsonian Report, 1871,
pp. 460, 461.

1871. Anniversary Address as President of the Philosophical Society

of Washington. (Delivered Nov. 18.) Bulletin Phil. Soc.
Washington, vol. i. pp. 5-14.

1872. Remarks ou Cosmical Theories of Electricity and Magnetism : an

Appendix to a Memoir by Prof G. B. Donati. Smithsonian
Report, 1872, pp. 307-309.

1872. On certain Abnormal Phenomena of Sound, in connection with

Fog-signals. (Read Dec. 11.) Bulletin Phil. Soc. Washington,
vol. i. p. 65, and Appendix ix. 8 pp.

1873. Letter to John C. Green, Esq., of New York, on his establishment

of the " Henry Chair of Physics" in the College of New Jersey.
Washington Daily Chronicle, Mar. 21, 1873.
1873. Telegraphic Announcements of Astronomical Discoveries. (]\Iay.)
Smithsonian Miscell. Collections, No. 263, vol. xii. pp. 1-4.

1873. Remarks on the Light-House Service. Report of Light-House

Board, 1873, pp. 3-7.

1874. Report of Investigations relative to Fog-Signals, and certain ab-

normal phenomena of Sound. Report of Light-House Board,

1874. Appendix, pp. 83-117.

1874. Memoir of Joseph Saxton. (Read Oct. 4.) Biographical Me-
moirs of !^at. Acad. Sci. vol. i. pp. 287-316.

1874. Remarks on Recent Earthquakes in North Carolina. Smithsonian

Report, 1874, pp. 259, 260.

1875. Remarks on the Light-House Service. Report of Light-House

Board, 1875, pp. 5-8.
1875. An account of investigations relative to Illuminating INIaterials.

Report of Light- House Board, 1875. Appendix, pp. 86-103.
1875. Investigations relative to Sound. Report of Liaht House Board,

1875. Appendix, pp. 104-126.

1875. On the Organization of Local Scientific Societies. Smithsonian

Report, 1875, pp. 217-219.

1876. Article on " Fog." for Johnson's Universal Cyclopiedia. Edited

by Dr. Barnard. J. Univ. Cycl. vol. ii. pp. 187, 188.

1876. Article on " Fog-Signals" for Johnson's Universal Cvclopsedia.

Edited by Dr. Barnard. J. Univ. Cycl. vol. ii. pp. 188-190.

1877. Article on "Lightning" for Johnson's Universal Cyclopaedia.

Edited by Dr. Barnard. /. Univ. Cycl.-vol. iii. pp. 32-36.

1877. Article on " Lightning-Rods" for Johnson's Universal Cyclopaedia.
Edited by Dr. Barnard. /. Univ. Cycl. vol. iii. pp. 36, 37.

1877. Remarks on the Light-House Service. Report of Light-House
Board, 1877, pp. 3-7.

1877. Report of Operations relative to Fog Signals. Report of Light-
House Board, 1877. Appendix, pp. 61-72.

1877. Address before the Philosophical Society of Washington. Bul-

letin Phil. Soc. Washington, vol. ii. pp. 162-174.

1878. On Thunder Storms. (Letter Oct. 13.) Journal Am. Electrical

Society, 1878, vol. ii. pp. 37-43.

141

368 BULLETIN OF THE

1878. Letter to Joseph Patterson, Esq., of Philadelphia, on the "Joseph
Henry Fund." (Dated Jan. 10.) Public Ledger and Tran-
script, May 14, 1878. The Press, of Philadelphia, May 14,
1878.

1878. Report on the Ventilation of the Hall of the House of Represen-
tatives. (Jan. 26.) 45th Cong. 2nd Sess. H. R. Report, No.
119, pp. 1-6.

L878. Report on the Use of the Polariscope in Saccharometry. (Feb. 5.)
Mis. Doc. 4.5th Cong. 2nd Sess. H. R.

1878. Opening Address, before National Academy of Sciences. (Read
April 16.) Proceedings Nat. Acad. Sci., vol. i. part 2, pp.
127, 128.

1878. Closing Address before National Academy of Sciences. (Read
April 19.) Proceedings Nat. Acad. Sci., vol. i. part 2, pp.
129, 130.

142