LIBRARY

UNIVERSITY OF
CALIFORNIA
SANTA CRUZ

MEMOIR

JOHN WILLIAM DRAPER.

1811-1882.

GEORGE F. BAKKKR.

KKAD HKFOIIK THK NATIONAL ACADK.MY, APRIL 21, 1880.

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LIBRARY OF THE

USITEESITT of CALHOJIIII.

LICK OB8ERVAT®RY«

BIOGRAPHICAL MEMOIR OF JOHN WILLIAM DRAPER.

MR. PRESIDENT AND (JENTLEMEN OF THE ACADEMY:

Tlie growth of science (luring the last half century is nowhere
better illustrated than in the changes which have taken place in
our views with regard to the doctrine of energy. Fifty years ago
the imponderables held full sway and heat light and electricity
were considered forms of matter quite as much as oxygen and sul-
phur and iron. True here and there an advanced thinker offered
his protests against this conception and even made experiments to
prove its fallacy ; but it was not until 1844 that Melloni established
the essential identity of radiant light and heat, and not until 1850
that Foucault made his experimentum crucis with regard to light.
No one in America, it is believed, had a larger share in contrib-
uting to this entire revolution of scientific opinion than the eminent
man who is the subject of this notice. For more than forty years
he labored earnestly, persistently, successfully in the field of radi-
ant energy. Viewed from the standpoint of to-day much of his
work may be criticised, of course ; but, as he himself has said, to
an observer " imbued with the true spirit of philosophy even the
shortcomings which are detectable in it are not without a charm.
From the better horizon he has gained he watches his author, who,
like a pioneer, is doubtfully finding his way, here traveling on a
track that leads to nothing, then retracing his footsteps, and again,
undeterred, making attempts until success crowns his exertions.
To explore the path to truth implies many wanderings, many in-
quiries, many mistakes."

Jonx WILLIAM DRAPER was born in the parish of St. Helens,
near Liverpool, England, on the 5th of May, 1811. His father,
the Uev. John C. Draper, was a clergyman of the Wesleya.ii de-
nomination and, like others in the same calling, was in quite
moderate circumstances. He was always greatly interested in
scientific subjects, however, especially in chemistry and astronomy,
and owned a (Jrogorian reflecting telescope, with which he made

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many observations. Young Draper received his earlier education
in his own home from private tutors employed for the purpose ; but
at the age of eleven he was sent to a public school at Woodhouse
Grove, then supported by the Wesleyans. The head master of this
school was an American. He was a man of considerable literary
ability and had contributed several articles of note to Rees' Ency-
clopedia, an authority then in great repute. Here young Draper
devoted himself assiduously to his classical and mathematical
studies and with marked success. So that, in recognition of the pro-
gress he had made in scholarship, he was selected in 1824 to deliver
the customary address from the school to the Wesleyan conference,
which met that year at Leeds. This was his first public oration
and it made a great impression upon him. Not long after this
event, however, he left the Woodhouse Grove school and returned
home, continuing his studies there, as before, under private tutors.

In the year 1829 the University of London was opened for in-
struction. The professor of chemistry in the new institution was
Dr. Edward Turner, a man whose reputation as a chemist placed
him among the first in England. Young Draper, who, with his
other studies, had taken up the study of science and had already
developed a decided taste for investigation, was sent to Dr. Turner's
laboratory to receive a course of instruction in chemistry. During
the two or three years which were thus occupied a pleasant and
profitable acquaintance was engendered, which ripened into a life-
long friendship. Owing to the unexpected death of his father, how-
ever, he did not take a degree at the University.

Before the Revolutionary War certain of Draper's ancestors on
his mother's side had come to America and had settled in Virginia,
founding a small Wesleyan colony. Subsequently others of the
family had crossed the ocean and joined the colony. Urged by
these relatives and accompanied by his mother and sister Draper
came to America in 1832, in his twenty-second year. The expecta-
tion of receiving a professorship in the denominational college in
the vicinity was one of the strongest inducements held out to him.
Repeated delays in starting, however, made the time of his arrival
much later than had been anticipated ; so that, when he reached
Virginia, the position he had hoped for had been given to another
person. He settled with his relatives at Christiansville, Mecklen-
burg county, where he devoted himself entirely to scientific research.

Although before leaving England he had published, jointly with

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.JOHN WILLIAM DKAl'KU.

a Fellow of the Geological Society, three papers on scientific sub-
jects, yet his first independent contribution to science was from this
Christian sville laboratory. It appeared in the American Journal
of Science and Arts for July, 1834, in the form of a letter to the
editors, the memoir in extenso appearing in the September number
of the Franklin Institute Journal for the same year under the title
" Some experimental researches undertaken to determine the nature
of capillary action." During this period he devoted his attention
also to improvements in the construction of galvanic batteries, to
investigations on the alleged magnetic action of light, and to the
analysis of a native chloride of carbon and of certain ancient coins
and medals.

Having decided to take the degree of Doctor of Medicine in course
Draper spent the winters of 1835 and 1836 in Philadelphia attend-
ing the medical lectures given in the University of Pennsylvania.
Here he came directly under the congenial and stimulating influence
of Dr. Robert I Tare's instruction in chemistry and physics, and in him
and in Dr. J. K. Mitchell, at that time the professor of chemistry
in the Jefferson Medical College, he found warm personal friends.
In their laboratories he did a large amount of scientific work, and
this not only alone, but also conjointly with these eminent men.
lie assisted Dr. Mitchell when he used for the first time in this
country the apparatus of Thilorier for the liquefaction of carbonic-
acid gas.

Draper graduated from the University in March, 1836. The sub-
ject of his thesis, as given in the Alumni Catalogue, was " Glandular
Action.'' It discussed the passage of gases through various barriers
not having visible pores, such as soap bubbles. He showed that
these transfusions take place as instantaneously as if there was no
obstacle in the way and are attended by many curious phenomena.
He put one gas inside the bubble and another on the outside ; he
then analyzed both and showed that the movement continues until
the gaseous constitution is the same within and without the bubble.
The special application of these experiments was to ascertain what
goes on in the air cells of the lungs ; how oxygen is introduced into
the blood and carbonic acid escapes from it in the act of inspi ra-
tion. Current report has it that the scientific character of this
thesis secured for it the special commendation of the medical faculty
and the high honor of publication at their hands. But as the thesis
itself is missing from the collection of the class of 1836, preserved

NATIONAL ACADEMY OF SCIENCES.

in the college records, and as no such title as the above appears in
any of his published papers, it has been found impossible, to verify
the statement. Two papers, however, covering much the same
ground appeared shortly afterward. The first, " Experiments on
Endosmosis," came out in the Journal of the Franklin Institute for
March and July. The second, entitled " Experiments on Absorp-
tion," which was much more extended, was printed in the Amer-
ican Journal of the Medical Sciences for May.

The published scientific memoirs of Dr. Draper had now won
for him a very considerable reputation. His graduating thesis
had by its originality and by the experimental ability shown in it
attracted the attention of the authorities of Hampden Sidney Col-
lege, Prince Edward county, Virginia. Accordingly, in the fall
of 1836, he was tendered, and accepted, the professorship of chem-
istry and natural philosophy in that institution. This appoint-
ment was especially agreeable to him, since it enabled him, as he
said, "to convert experimental investigation, thus far only an-
amusement, into the appropriate occupation of his life." In the
new sphere of labor thus opened to him he continued his scientific
researches with largely increased experimental facilities.

In 1837 a movement was made to establish a medical school in
connection with the University of the city of New York, and Dr.
Draper was elected professor of chemistry in the new institution.
The financial embarrassments of that year, however, crippled the
university and the project was temporarily abandoned.

In 1839, however, he was elected professor of chemistry in the
undergraduate department of that university, and removed with his
family to the city of New York. In 1840, in conjunction with Drs.
Mott, Bedford, Pattison, and Revere, he took an active part in
organizing the medical department, in which he became the pro-
fessor of chemistry. His intimate relations with the chancellor, the
Hon. Theodore Frelinghuyseu, resulted in his assuming a large
share in the preparation of the constitution of the new department,
to the wise provisions in which its subsequent prosperity has been
largely due. Moreover, in doing this he exerted a marked influ-
ence on the development of medical science in the city of New
Yo'rk. At that time there were but few medical students there,
probably not more than forty or fifty. But in the session of 1841-
'4*2 the University Medical School alone enrolled 239 students, and
the number in attendance at the College of Physicians and Sur-

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JOHN WILLIAM DRAPER.

geons was also largely increased. The new movement was, from
the first, greatly indebted to the influence exerted in its favor by the
New York Herald; and this arose out of the relations of personal
friendship which existed between Dr. Draper and Mr. James Gor-
don Bennett. To these gentlemen, it has been said, more than to
any others, New York owes its present advanced position as regards
medical education. Entire pages of the Herald were devoted to
reports of the lectures and clinics at the University; and a strictly
medical journal, published by Mr. Bennett and called The Lancet,
kept the doings of the University school constantly before the med-
ical profession.

The first president of the new medical college was Dr. Valentine
Mott, who was also professor of surgery. Dr. Draper was elected
secretary. In 1850, upon the resignation of Dr. Mott, he succeeded
to the presidency, and by his active measures and wise counsels,
inaugurated a period of unexampled prosperity for it. In his own
instruction Dr. Draper had always maintained that the functions
of an organized being were performed under the operation of chem-
ical and physical law, in opposition to the theory of vital force then
in vogue among physiologists. And now, when the new views of
Liebig and his school gave increased importance to the chemical
relations of physiology, he was among the first to recognize their
value, and, as a consequence and at his request, physiology was
added to his chair. He resumed his researches on physiological
subjects, and his lectures were replete with novel and radical ideas.

One of the severest trials through which the medical department
was called to pass during Dr. Draper's presidency was the entire
destruction by fire, in 1865, of its college building in Fourteenth
street. But the same untiring energy which had secured the edi-
fice that was destroyed not only made prompt provision for the con-
tinuance of the lectures, but speedily repaired the loss. Though in
the midst of the course of instruction, not a single lecture was lost;
and in the fall of 1869 he gave the introductory lecture of the course
in the new building, which is still occupied by the school, and which
had been provided, as he told the class, by the generosity of Mr.
Courtlandt Palmer.

Dr. Draper's personal loss was especially severe. Not only were
his extensive library, his lecture notes, and the note-books which
contained the results of his experimental investigations consumed,
but his entire collection of chemical, physical, and physiological

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NATIONAL ACADEMY OF SCIENCES.

apparatus, that used to illustrate his lectures as well as that more
valuable portion which he had used in his researches, was destroyed.
The pecuniary loss he estimated at $15,000. This was the second
time he had suffered severely by fire. In 1853 almost the entire
edition of his scientific memoirs and essays up to 1844, together
with the illustrative plates, were destroyed by fire in the publishing
house of Harper & Brothers.

In 1873 Dr. Draper severed his connection with the medical de-
partment of the University, but continued his instruction in chem-
istry to the undergraduate classes until 1881, the year preceding his
death.

It has been already stated that Dr. Draper developed very early
in life a decided fondness for science and scientific investigation.
It is said that his decision to devote himself to the experimental
study of nature arose from the accidental observation that in a glass
vessel containing camphor beautiful crystals had condensed only on
the illuminated side. A desire to understand the cause of this phe-
nomenon led him to read whatever books he could obtain which
treated of the chemical and mechanical action of light, of adhesion
and of capillary attraction, and subsequently to experiment for
himself in these and similar subjects.

Capillary attraction was the subject of his first extended research.
Clairaut had already shown that the phenomenon was due to the
adhesion of the solid for the liquid as compared with the cohesion
of the latter, and that if the mutual attraction of a solid and a
liquid amount to half the cohesion of the liquid there will be capil-
lary depression ; but that if this attraction be greater than half the
cohesive value the liquid will rise in the tube. Dr. Young had
maintained that the bounding meniscus of a liquid was an elastic
surface and acted by its tension to elevate or depress the column
which it terminated. And Laplace, in the more elaborate memoir
contained in his Theorie de 1'action Capillaire, published in the
supplement to the tenth book of his Mecanique Celeste, had at-
tributed the rise or fall of liquids to the attraction of a thin layer of
the liquid immediately adjacent to the walls of the tube. Dr.
Draper's attention was first drawn to the subject, as he tells us, dur-
ing those tiresome moments of returning health which follow an
autumnal fever. " Perhaps," he says, " if there be any merit in these
experiments it may hereafter be of service to some one to know that
they were begun in sickness and in a land of strangers ; that they

356

JOHN WILLIAM DRAPER.

were pursued in all the calamity of family bereavement, and in the
depths of forests, alike unused to music, to poetry, to philosophy."
His first experiments were addressed to the direct determination of
the attraction between mercury and glass, with the view of testing
Clairaut's mathematical deduction. After repeated trials he found
that a strong and uniform adhesion was obtained when the mercury
was pure and warm and the glass perfectly clean. Repeating the
experiment with an amalgamated disk of copper, of the same size,
the weight required for separation was regarded as measuring the
cohesion of the mercury itself. The results of a number of experi-
ments showed that in no case did the attraction of mercury for
glass amount to half the cohesion of the mercury. But since a glass
plate on the surface of water is wetted, even after separation, it is
obvious that in this case the adhesion is greater than the whole co-
hesion ; hence the rise of water in a tube of glass is easily accounted
for.

But an unexpected phenomenon was developed. On connecting
the mercury, dry and warm, to a gold leaf electroscope no disturb-
ance of the leaves took place so long as the glass plate was in con-
tact with its surface. But on separating them — and it required
considerable force to do this — both the mercury arnd the glass be-
came strongly electrified, the mercury being negative and the glass
positive. Indeed, the development of electrification was so de-
cided as to tear asunder the leaves of the electroscope. Dr. Draper
naturally concluded that contact of mercury and glass developed
electrification ; that while in contact the electricity was " disguised "
and appeared only on separation ; and that since the two were op-
positely and strongly electrified, the force requi red to separate them
measured the electrical attraction. But this force measured also
the adhesion, by hypothesis; and hence adhesion must be an electri-
cal attraction. Two striking confirmations of this theory are given
in the memoir. In the first he repeated the mercury experiment
with disks of glass, gum-lac, sealing wax, sulphur, and beeswax, and
proved that the electrification, as measured with the torsion balance,
was for each disk proportional to the adhesion as measured by the
force required for separation ; and that for the several disks ex-
amined the values obtained diminished in the above order. In the
second he showed very ingeniously that electrification exercises an
apparent control over all the phenomena of capillary attraction.
One form of his apparatus consisted of an inverted siphon, the

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larger leg being about half an inch and the smaller about one-
tenth of an inch in diameter. Mercury is poured into the larger
and dilute sulphuric acid into the smaller tube, the latter liquid
resting on .the former. On connecting the mercury with the
negative terminal of a voltaic battery and the acid with the positive
the mercury falls in the tube. Reverse the battery-terminals and
the mercury column rises. Moreover, Dr. Draper observes that all
these changes in position are accompanied by certain definite changes
of figure of the bounding surface, and shows that this might have
been expected from the theory of Laplace. Placing a globule of
mercury in acidulated water in contact with the negative terminal
of the battery he found that whenever contact of the positive termi-
nal was made with the acid an instant deformation of figure took
place, the upper surface being flattened, so that the mercury touched
the inclosing tube all around in a complete ring. This memoir,
published in 1834, must be considered in all respects a remarkable
one, and anticipates clearly many of the more important later dis-
coveries.

The phenomenon of osmose described by Dutrochet in 1827 had
been noticed by Dr. Draper in the above memoir. A few years
later Dr. J. K. Mitchell had published a valuable paper on the
osmotic phenomena observed in membranes of caoutchouc. When
Dr. Draper entered upon his medical studies in Philadelphia, there-
fore, it was natural that he should take a lively interest in the phe-
nomena referred to, and particularly in their physiological relations.

His experiments on gaseous osmose were original and important
and were based on the simple assumption that any substance in
contact with any other tends to diffuse into it. He found that am-
monia gas penetrated almost instantly films of shellac, gold leaf
and mica, and especially liquid films, whether these were thin, as in
a soap bubble, or were composed of a layer of water of quite con-
siderable thickness. When such a layer separated carbonic-acid
and hydrogen gases, for example, he observed that the phenomenon
was a simple one and consisted in the mutual solution of the gases
in the liquid, their transference through the film, and their subse-
quent evaporation, the process ceasing when the atmosphere on both
sides of the layer was the same. Using then a membrane of caout-
chouc he sought to discover whether gaseous osmose could be pre-
vented by pressure ; and he experimentally proved that sulphur-
ous acid passed into air under a pressure of 7£ atmospheres, car-

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JOHN WILLIAM DKA1MOK.

bonic acid under one of 10 atmospheres, and hydrogen sulphide
under a pressure of 24.1 atmospheres. Since the force impelling
the particles of one gas into the interstices of another, without a
septum, never exceeds the pressure of one atmosphere, it is plain
that the source of this remarkable power must lie in the membrane
itself. So that the caoutchouc membrane must, in this experiment,
have condensed the sulphurous-acid gas and the hydrogen-sulphide
gas into liquids, which were then, in this condition, transferred
through the film and evaporated on the other side precisely as with
the water film. •

AVith regard to liquid osmose Dr. Draper shows that the only
essentials are : First, that both the liquids should wet the barrier ;
second, that they should rise to different heights in tubes made of it,
and, third, should be capable of uniting chemically with each other.
All solid bodies which act as barriers have pores, which, while too
small to permit leakage, yet allow interchange of indefinitely small
columns of liquid. Such are plates of Villarica porcejain clay, of
Bru/il indurated steatite, and of certain varieties of compact sand-
stone. No liquid can pass a barrier the pores of which it cannot
wet; but, since water by electrifying it positively may be made to
wet mercury, electricity modifies osmose. The separation of water
from litmus through a membrane having alcohol on its other side,
he concludes, is " only a refined kind of filtration, which, probably,
may hereafter become of considerable importance in its applications
in the arts, as in the separation of coloring matter from solutions,
or the preparation of medicines, such as the vegetable alkalies, which
should be formed from colorless solutions."

In a paper published in 1846 Dr. Draper applies these principles
very ingeniously to explain the circulation of the sap in plants and
the blood in animals. Both these motions, he says, depend on the
following simple physical principle: "That if two liquids communi-
cate with one another in a capillary tube or in a porous or paren-
chymatous structure and have for that tube or structure different
chemical affinities movement will ensue ; that liquid which has the
most energetic affinity will move with the greatest velocity and may
even drive the other fluid entirely before it." In the rootlet the
phenomenon is simply an osmotic one, a flow taking place from the
water without into the mucilaginous sap within, precisely as water
flows into gum-water through a bladder. In the leaf the weak
ascending watery sap rises to its upper surface and there obtains

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carbonic acid from the air. The sunlight effects the decomposition
of this, changing it to a mucilaginous solution. On the principle
now indicated the water will drive the mucilaginous solution before
it, forcing it back along its proper vessels into the stem. The flow
of the sap in plants therefore is controlled by sunlight, since this
agent determines the production of the mucilaginous solution, which
is the motive power. When the season advances the flow slackens,
because the formation of the elaborated sap diminishes. Both in
the rootlet and in the leaf consequently the action is due to the
fact that two different liquids are brought in contact with a porous
solid, which is wetted by both of them, but unequally. Hence that
one which has the greatest affinity for the solid and wets it most
perfectly passes most rapidly through it and drives the other one
before it. The descent of the elaborated sap is therefore quite as
positive an action as the ascent of the unelaborated.

In animals the blood in the arterial capillaries of the systemic
circulation is charged with oxygen, which has an intense affinity for
the carbon and hydrogen of the walls. In the venous capillaries
the blood is charged with carbonic acid having no affinity for these
tissues. The arterial blood will drive the venous blood before it,
therefore. In the pulmonic system the venous blood is presented to
the air cells, for the oxygen in which it has a strong affinity, while,
the arterial blood which has absorbed this oxygen has no longer
any. Movement ensues as before, but as now the affinities arc
reversed the flow is from the veins to the arteries. The systemic
circulation is due therefore to the oxidizing action of the arterial
blood and the flow is from the artery to the vein. The pulmonary
circulation is due to the oxidation of the venous blood and the flow
is from the venous to the arterial side. Both arise from the common
principle that "a pressure will always be exerted by the fluid which
is ready to undergo a change upon that which has already under-
gone it — a pressure which, as there is no force to resist it, will
always give rise to motion in a direction from the changing to the
changed liquid."

"A true theory," says Dr. Draper, " is like a window of crystal
glass, through which we can see all objects in their proper positions
and colors and relations, no matter whether they are such as are
near or those that are at a distance ; no matter whether they are
directly before us or enter only obliquely into the field of view.
A fictitious theory is like a Venetian blind, which has to be set in a

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JOHN WILLIAM DKAI'KR.

certain position with respect to the observer and only shows him
objects for which it lias been adjusted, and those in an unsatisfactory
manner; but if he moves to one side or to the other, or endeavors to
see objects which are not directly in his way, his view is intercepted,
or, perhaps, unless he makes a new adjustment, the light is shut out
altogether."

It is, however, by his researches upon Radiant Energy that John
W. Draper is best known in the world of science. In an able
memoir on the Production of Light by Heat, published in 1847,
he described some ingenious experiments with incandescent platinum,
by which he conclusively proved : First, that the temperature at
which this metal became incandescent was fixed and constant at
977° F. ; and, second, that various other substances, such as brass,
antimony, gas carbon, lead, and the like, all became luminous at the
same temperature, which was that of the gun barrel in which they
were inclosed. By means of an extemporized spectroscope he ex-
amined the platinum as its temperature was gradually raised by the
electric current and showed that as this temperature rose from
1,095° to 2,130° F. the spectrum gradually extended itself toward
the violet; rays of an increasing refrangibility being successively
produced, the frequency of the vibrations increasing with the tem-
perature. In order to bring these observations to a common standard
of comparison Dr. Draper originated the simple device of using the
sun spectrum with its fixed lines as a reference-spectrum, daylight
being reflected to the prism through a narrow aperture occupying
exactly the position in which the platinum strip was to be subse-
quently placed. The relation of the temperature of incandescent
platinum to the amount of light emitted by it was also examined,
and it was found, photometrically, that at 2,590° F. the light emitted
was more than thirty-six times as much as that given out by the same
strip of metal at 1,900°. Moreover, on measuring, by means of the
thermo-pile, the total energy radiated from the incandescent strip,
he found that if he took the heat radiated at 980° as unity, that
emitted at 2,360° was 17.8; the heat radiated between 1,000° and
1,300° being nearly the same in amount as that radiated in passing
from common temperatures up to 1,000°. In closing this memoir
the author says : *' The preceding experiments furnish an easy means
of supplying * * * what might be termed a ' unit lamp.' A
surface of platinum of standard dimensions, raised to a standard
temperature by a voltaic current, will always emit a constant light.

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NATIONAL ACADEMY OF SCIENCES.

A strip of that metal one inch long and one-twentieth of an inch
wide, connected with a lever by which its expansion might be meas-
ured, would yield at 2,000° a light suitable for most purposes. More-
over, it would be very^easy to form from it a photometer by screen-
ing portions of the shining surface. An ingenious artist would have
very little difficulty, by taking advantage of the movements of the
lever, in making a self-acting apparatus, in which the platinum
should be maintained at a uniform temperature, notwithstanding any
change taking place in the voltaic current."

In the following year Dr. Draper published a noteworthy memoir
on the production of light by chemical action. In this memoir he
investigates by means of the prism the character of the light which
is produced by combustion, answering thus his own query, " Can
any connection be traced between the chemical nature of a substance
or the conditions under which it burns and the nature of the light
which it emits ?" With a slit, a prism, and an observing telescope
he examined the flames of oil, of alcohol, of alcoholic solutions
of boric acid and strontium nitrate, of phosphorus, of sulphur, of
carbonic oxide, of hydrogen, of cyanogen, and of arsenetted hydro-
gen. The flame of the oil was yellow ; of the alcohol, pale blue ; of
the boric acid, green; of the strontium, red; of the phosphorus,
yellowish white; of the sulphur and carbonic oxide, blue; of the
hydrogen, pale yellow ; of the cyanogen, lilac, and of the arsenetted
hydrogen, white. "Notwithstanding this diversity of color," he
says, "all these flames, as wTell as many others that I have tried,
yield the same result; every prismatic color is found in them. Even
in those cases where the flame is very faint, as in alcohol and in hy-
drogen gas, not only may red, yellow, green, blue, and violet light
be traced, but even bright Fraunhoferian lines of different colors."
The spectra given by these variously-colored flames were carefully
drawn and their peculiarities were pointed out. When, he thus
examined the flame of cyanogen he beheld, as he says, " a spectrum
so beautiful that it is impossible to describe it by words or depict it
in colors. It was crossed throughout its extent by black lines sep-
arating it into well-marked divisions. I could plainly count four
red rays of definite refrangibility, followed by one orange, one yel-
low, and seven green rays, while in the more refrangible spaces were
two extensive groups of black lines, recalling somewhat from their
position, but greatly exceeding in extent, Fraunhofer's lines G and
H in the sun's rays." He considered the interior lilac cone to be

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JOHN WILLIAM DRAPER.

the source of the fixed lines of the bright spectrum, and he observed
that new lines are developed as the temperature rises. " Do not the
various facts here brought forward," he says, "prove that chemical
combinations are attended by a rapid vibratory motion of the par-
ticles of the combining bodies, which vibrations become more fre-
quent as the chemical action is more intense ? " This memoir may
be regarded as one of the earliest contributions to spectrum analysis.

In a subsequent memoir, written in 1857, Dr. Draper uses the fol-
lowing remarkable language : " In other cases dark lines are replaced
by bright ones, as in the well-known instance of the electric spark
between metallic electrodes. The occurrence of lines, whether bright
or dark, is hence connected with the chemical nature of the substance
producing the flame. For this reason these lines merit a much more
critical examination, for by their aid we may be able to ascertain
points of great interest in other departments of science. Thus, if
we are ever able to acquire certain knowledge respecting the physi-
cal state of the sun and other stars, it will be by an examination of
the light they emit." Surely these researches, with the prophetic
conclusions which he drew from them, entitle Professor Draper to a
recognized position among the pioneers in the science of prismatic
analysis.

Some of the earliest of Dr. Draper's investigations were directed
to a determination of the various forms of energy which exist in
solar light. The chemical action of light was always a fascinating
subject to him and he had made many interesting experiments to
ascertain the effect of different kinds of light upon chemical change.
These chemical actions were investigated in three different direc-
tions. The first of these was photography. For many years he
had studied the action of light in changing the color of metallic
salts, and he had already long been accustomed to apply the photo-
graphic process to the solution of physical problems when Daguerre's
discovery was announced in 1839. He welcomed the daguerreotype
enthusiastically, made a special study of it, and in the same year
improved it so much that he took by its means the first portrait of
the human face. In these days of rapid emulsion processes the
directions he gives for taking a daguerreotype appear interesting.
" In the first experiments I made," he says, " the face of the sitter
was dusted with a white powder, but a few trials showed that this
was unnecessary." "On a bright day and with a sensitive plate por-
traits can be obtained in the course of five or seven minutes in the

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diffused daylight even when an ammonia-sulphate of copper cell
is interposed. The hands should never rest upon the chest, for
the motion of respiration disturbs them so much as to make them
of a thick and clumsy appearance, destroying also the representa-
tion of the veins on the back, which, if they are held motionless,
are copied with surprising beauty. A person dressed in a black
coat and open waistcoat of the same color must put on a temporary
front of a drab or flesh color, or by the time that his face and the
fine shadows of his woolen clothing are evolved his shirt will be
solarized and be blue or even black, with a white halo around it.
Owing to the circumstance that yellow and yellowish browns re-
quire a long time to impress the substance of the daguerreotype
persons whose faces are freckled all over give rise to the most ludi-
crous results — a white portrait mottled with just as many black
dots as the sitter has yellow ones." On the 23d of March, 18-10,
Dr. Draper presented to the Lyceum of Natural History of New
York the first representation of the moon's surface ever taken by
photography. The daguerreotype plate was exposed twenty minutes
and the image was about an inch in diameter. In this image the
places of the dark spots can be indistinctly traced.

The second method by which he studied the action of the chemi-
cal rays was based upon the effect which they produced upon chlorine
gas. In 1843 he announced to the British Association that this gas
underwent a decided modification under the influence of sunlight, in
consequence of the absorption of these chemical rays. In virtue of
this change in its character it was now able to unite directly with
hydrogen, a property not possessed by chlorine kept in the dark.
Hence he announced the discovery of a new imponderable in solar
light which was analogous to light and heat, and which was the
agent producing chemical change. To this new agent he gave the
name " tithonicity," the origin of which he thus describes : " The
chemical rays are associated with the rays of light, accompanying
them in all their movements, originating with them, and, unless
disturbed, continuing to exist along with them. But should a com-
pound beam like this fall upon a sensitive surface the chemical rays
sink into it, as it were, and lose all their force, and the rays of light
are left alone. Photographic results thus obtained from the repos-
ing of the chemical rays on the sensitive surface are not, however,
in themselves durable, for the rays escape away under some new
form. Tithonus was a beautiful youth whom Aurora fell in love

364

JOHN WILLIAM DRAPER.

with and married in heaven. The fates had made him immortal ;
but, unlike his bride, in the course of events he became feeble and
decrepit, and, losing all his strength, was rocked to sleep in a cradle.
The goddess, pitying his condition, metamorphosed him into a grass-
hopper. The fact and the fable agree pretty well, and, indeed, the
playful coincidence might be carried much farther. The powers of
photography, which bring architectural remains and the forms of
statuary so beautifully and impressively before us, might seem to be
prefigured by the speaking image of the son of Tithonus and Au-
rora that was to be seen in the deserts of Egypt. Besides this such
words as tithonoscope, tithonometer, tithonography, tithonic effect,
ditithonescence are musical in an English ear." In the same year
he described a tithonometer or instrument for measuring these chem-
ical rays based on their action upon chlorine. The apparatus con-
sisted of an inverted siphon tube, the shorter limb of which was
closed, the longer drawn out and graduated. By means of wires of
platinum sealed into the shorter limb the solution of hydrochloric
acid which it contained could be decomposed by a voltaic current,
and this limb filled with mixed hydrogen and chlorine gases. When
the image of a flame, formed by a convex lens, was caused to fall
on the sentient tube the liquid in the longer limb began instantly to
descend, moving regularly over the scale so long as the exposure was
continued. This instrument, while much simpler, appears to be
quite as sensitive as the one described by Bunsen and Koscoe many
years later (1856).

The third method which Dr. Draper employed for studying the
action of the chemical rays was based on the growth of plants.
Already, in 1837, he had investigated the phenomenon of the de-
composition of solar light by leaves, and had shown that these leaves
absorbed certain rays. But these early experiments were made
under colored glasses and were not entirely conclusive, other rays
passing simultaneously through the media used. When seeds were
made to germinate under these glasses, however, he found that the
plants under the red and the violet glasses were as perfectly etiolated
as if they had been kept in the dark ; while those under the yellow
glass promptly assumed a green color and developed rapidly. In
order to obviate the objection raised to colored glasses a crop of
seeds was caused to germinate in a long box placed in the dark and
the young plants were then exposed to the action of a solar spectrum.
Those in the yellow speedily turned green, while those in the red
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NATIONAL ACADEMY OF SCIENCES.

and in the violet regions remained unaffected. An attempt was
then successfully made to effect the decomposition of carbonic-acid
by the green parts of plants also placed in the solar spectrum. Water
freed from air by boiling was saturated with carbonic acid gas, and
in it was immersed grass whose surfaces had been carefully freed of
air. Seven tubes thus prepared were placed each in one of the seven
colors of the spectrum and carefully observed. In a few minutes
after the beginning of the experiment the tubes on which the orange,
the green, and the yellow rays fell began to give off minute bubbles
of gas, and in an hour and a half sufficient was collected for accurate
measurement. Forty-three volumes of gas were produced in the
yellow-green, twenty -four and three-fourth volumes in the red-orange,
four and one-tenth in the green-blue, one in the blue, and none in
the other colors. The memoir in which these results were first pub-
lished was read to the American Philosophical Society on the occa-
sion of its centennial anniversary in 1843.

But it was mainly by means of spectrum investigations that Dr.
Draper studied the components of radiant energy. In the earlier
stages of his work he, in common with his contemporaries, regarded
heat and light as imponderable agents, entirely distinct from one
another, though coexisting in solar light. In his later memoirs*
however, having accepted the essential unity of radiant energy, he
discusses with great ability, in his memoir of 1872, on the distribu-
tion of the chemical force in the spectrum, the dependence of the
result upon the nature of the surface upon which the light falls. In
this memoir he shows : First, that so far from chemical influences
being restricted to the more refrangible rays every part of the spec-
trum, visible and invisible, can produce chemical changes and can
modify the molecular arrangement of bodies ; and, second, that the
rays effective in producing chemical or molecular changes in any
special substance are determined solely by the absorptive power of
that substance. Thus silver salts, for example, blacken most
readily in the more refrangible regions. But even these have their
peculiarities. An iodide of silver plate long exposed to the spectrum ?
with absolute exclusion of extraneous light, is normally darkened
in the more refrangible and receives a white stain in the less re-
frangible regions. If, however, the plate receive weak diffused
light during exposure it will be found on developing that every ray
that the prism can transmit, from below the extreme red to beyond
the]extreme violet, has been active. Indeed, it was by this very process

360

JOHN WILLIAM DRAPER.

that Dr. Draper, in 1843, discovered the dark lines «, ft, ? in the
ultra-red. Essentially the same results are obtained if the plate is
submitted to a weak light for a few moments previous to its ex-
posure to the spectrum. It would seem, therefore, as if the less re-
frangible rays could reverse the general action of light upon iodide
of silver. So that, while every ray of the spectrum is capable of affect-
ing this substance, the more refrangible promote, the less refrangible
arrest, this general action of light upon it.

Bitumen and resins also receive impressions from below A to be-
yond H, every ray in the spectrum acting. In the bleaching of
flowers by light " the rays which are effective in the destruction of
any one vegetable color are precisely those which by their union
produce a tint complementary to the color destroyed." Chlorine
and hydrogen unite under the action of the indigo ray, which is seven
hundred times more active than the ultra-red. Dr. Draper con-
cludes, therefore, "that the sensitiveness of any given preparation
to light depends on its chemical nature and its optical qualities con-
jointly, and that it is possible to exalt or diminish the sensitiveness
of a given compound by changing its optical relations."

The results of Dr. Draper's investigations with the prismatic
spectrum, however, were not altogether satisfactory to him, owing
to a defect which originates in the very cause which gives rise to the
spectrum itself — unequal refrangibility. If we compare together
two sets of rays, one taken in the red and the other in the violet
region, it is obvious that, in the same spectrum, from the very cir-
cumstance of their greater refrangibility, those in the violet will be
relatively more separated from each other than those in the red.
The result of this increased separation in the more refrangible
regions is to give an apparent dilution to them, while the less re-
frangible regions are concentrated.

Accordingly, in May, 1843, Dr. Draper succeeded in inducing
Joseph Saxton, the eminent mechanician of the United States mint
at Philadelphia, to rule for him a diffraction grating. With this
grating, which was of glass and five-eighths of an inch by one-third
of an inch in size, the diffraction spectrum was produced and the
above difficulties avoided. Dr. Draper effected a great improve-
ment in the grating by silvering its ruled surface with tin amalgam,
thus producing a reflected spectrum which was far more brilliant
than the transmitted one, though he suggested that perhaps it would
be better to rule them originally on steel or speculum metal. It

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NATIONAL ACADEMY OF SCIENCES.

was at this time, too, that Dr. Draper suggested that the different
regions of the spectrum should be indicated by their wave-lengths.
" Since the deviations of the different fixed lines, B, C, D, in the
interference spectrum," he says, " are proportional to the lengths of
the undulations which they respectively represent, by designating
the different points of the spectrum by their wave-lengths, the sub-
division may be carried to any degree of minuteness ; the measures
of one author will compare with those of another and the different
phenomena of chemical changes occurring through the agency of
light become allied at once with a multitude of other optical re-
sults."

It was with this grating that the diffraction spectrum was for the
first time photographed. A daguerreotype plate, rendered sensitive
by iodine and then by bromine, and exposed for half an hour, gave
a maximum sensitiveness at wave-length 0.00001538 Paris inch.
A plate prepared by iodine, bromine, and chloride of iodine, and ex-
posed for an hour, gave a maximum at the same point, the decom-
position extending from wave-length 0.00002007 in the green to
0.00001257 in the violet. In these photographs the fixed lines were
beautifully distinct.

Dr. Draper, too, was among the first to point out the unsatisfac-
tory character of the measurements which have been made with the
prismatic spectrum on the distribution of heat. Since the less re-
frangible regions are much compressed and the more refrangible
much dilated, the measures obtained by means of a uniform move-
ment through the spectrum cannot be accepted as expressing the
true distribution. Hence, in 1857, he attempted to determine the
curve of distribution in a diffraction spectrum ; but the results, though
suggestive, were not conclusive. Subsequently, in 1872, he devised
a simple modification of the prismatic spectrum method, which ac-
complished practically the result which he had desired to obtain
with the interference spectrum. Using Angstrom's values expressed
in ten millionths of a millimeter, the wave length of the line A is
7,604 and that of H2 3,933, these lines bounding very nearly the
visible spectrum. The middle point is, therefore, at 5,768. If,
now, the heat be determined first in the region from 7,604 to 5,768,
and then from 5,768 to 3,933, may not the question of its uniform
distribution be thus settled ? Upon making the experiment it was
found that the two halves of the spectrum gave identically the same
amount of heat, and this whatever be the material of the prisms.

368

.JOHN WILLIAM DlIAl'KK.

Hence it follows that any two series of undulations in the spectrum
will have the same heating power, no matter what their wave-
lengths may be.

Continuing his spectrum investigations, Dr. Draper next sought
to determine the law of the distribution of light. Mosotti, in Italy,
had already studied the diffraction spectrum, and had shown that
the maximum of illuminating power lay in the yellow, the intensity
declining symmetrically on either side. The photometric method
of Bouguer Dr. Draper had used in 1847, with good results, to
measure the intensity of the light radiated from incandescing plat-
inum ; and he now, in 1879, sought to construct a spectrometer on
the same principle which should measure light-intensity. The prin-
ciple is a well-recognized one in optics. It is that any light becomes
invisible in presence of another light sixty-four times as strong. If,
as Mosotti had maintained, the yellow be the brightest of the spec-
trum colors, then in presence of an extraneous light thrown on
the spectrum and variable at will, the yellow will remain after the
red and orange on the one side, and the green, blue, and violet on
the other, have been extinguished. But on making the experiment,
throwing the extinguishing white light through the third telescope
of an ordinary spectroscope, so as to reflect it to the eye from the
face of the prism, Dr. Draper found that the colors of a gas-flame
spectrum disappeared in the inverse order of their refrangibility,
the red being the last to disappear. Analogous experiments with
the spectrum of sunlight, which was sometimes thrown on a screen
and sometimes on the ground glass of a camera and extinguished
by daylight, gave precisely similar results. On gradually opening
the shutter admitting the daylight, the extreme violet disappeared
first, and then the other colors in the inverse order of refrangibility
as before. On closing the shutter the red first came into view, and
then the other colors successively. Obviously, if this result is due
to the compression at the red end of the prismatic spectrum, then it
should not be found in that produced by diffraction ; and on mak-
ing the experiment Dr. Draper saw, not without pleasure, that as
the intensity of the extinguishing beam increased all the colored
spaces yielded apparently in an equal manner and disappeared at
the same moment. On diminishing the intensity of the extraneous
light he observed that they all came into view apparently at the
same time. The yellow, as before, showed no superiority over the
other colors in resisting extinction. It would seem, therefore, that

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the apparent brightness of the yellow, as seen by the eye, is a purely
physiological phenomenon.

Another subject to which Dr. Draper devoted a large share of
attention was phosphorescence. In his first memoir on this subject,
published in 1851, he discusses the general character of the phenom-
enon, and restricts the term phosphorescent to those bodies which
shine in the dark after exposure to light or on being heated. Fluor-
spar, of the variety known as chlorophane, which yields a superb
emerald-green light, was selected for experiment, He found that
when made to phosphoresce by the electric spark it underwent neither
expansion nor contraction, nor any other molecular change detectable
in polarized light. He did observe a minute evolution of heat, but
could detect no electrical change. Nor did the presence of a pow-
erful magnetic field appear to affect the result. On measuring the
amount of light emitted it appeared that this splendid green light
was photographically twenty- four times, and photometrically three
thousand times, less intense than that of the small flame of an oil
lamp taken for comparison. But he noticed that the quantity of
light emitted by a phosphorescent body was proportional to the in-
tensity of the light to which it had been exposed. In 1844 Dr.
Draper determined that the special phosphorogenic rays of the
spectrum were the violet rays. In this research he used a quartz
train and threw the spectrum upon a screen covered with calcium
sulphide. He observed, further, that for the transient light of the
spark quartz is transparent but glass is opaque — that is, so far as a
surface of calcium sulphide is concerned, though not a sensitive
silver surface. Moreover, while glass is opaque to phosphorogenic
rays from the spark, it transmits freely those from incandescent lime,
so that the calcium light, the light of an oil lamp, and sunlight can
excite phosphorescence through glass ; that of the electric spark or
of the voltaic discharge in mercury cannot. If, however, the latter
be continuous an effect is produced even through glass.

In his last scientific memoir, published near the close of 1880,
Dr. Draper called attention to the striking resemblance existing
between a photograph of the solar spectrum taken on silver iodide
and a phosphorograph taken on luminous paint. The former, when
taken in presence of a weak extraneous light, shows the three
regions which were pointed out by him in 1842 : (1 ), a middle region,
extending from the boundary of the green and blue to a little be-
yond the violet ; here the silver iodide is blackened ; (2), below this

370

JOHN WILLIAM DRAPER.

and extending from the green to the ultra-red is a strongly-marked
region in which the action of daylight has been altogether arrested
or removed, the daylight and the sunlight having apparently coun-
terbalanced and checked one another ; and (3), a similarly protected
region, much shorter, beyond the violet. The phosphorograph, in
the absence of extraneous light, shows a shining region correspond-
ing to number one of the photograph. But if foreign light inter-
venes there is annexed to this region another, including the less
refrangible spaces, of decided blackness, broken, however, at a short
distance below the red by a luminous rectangle of considerable
width, formed by the coalescence of the bands «, /5, Y- There is also
a similar but smaller region in the violet. In this memoir Dr.
Draper notices the rapidity with which the red spectrum rays ex-
tinguish phosphorescence.

The electrical investigations which were undertaken by Professor
Draper were much fewer in number than those on light. One of
the most important of these was a paper on the electromotive power
of heat, published in 1840, in which he discusses the electromotive
force developed in pairs of different metals as the temperature rises
and gives values for wires of copper-iron, silver-palladium, iron-
palladium, platinum-copper, iron-silver, and iron-platinum, obtained
with one junction kept at 32° and the other raised either to 212° or
to 6G2°F. He gives curves of the thermo-electric action of these
metals, the abscissas being temperatures and the electromotive forces
ordinates, constituting a thermo-electric diagram. In this diagram
the curves of iron-palladium and copper-silver are concave toward
the axis of abscissas, while those of iron-platinum, copper-platinum,
and silver-palladium are convex toward this axis. He observed
also that the increase of electromotive force with temperature dif-
fered for the different pairs. He calls attention to the anomalous
results which are given by pairs into which iron enters, and gives
the diagram of a copper-iron couple, the maximum ordiuate of which
is at 650° and the neutral point at a temperature at which an alloy
of equal parts of brass and silver melts. The paper concludes with
several suggestions in regard to the forms which it is desirable to
give to the components of a thermo-electric couple.

In 1834 he studied the action of the galvanic battery and pub-
lished an account of some improvements in its construction which
his experiments had suggested. In 1835 he repeated the experi-
ments of Morichini and Mrs. Somerville on the reputed magnetiz-

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NATIONAL ACADEMY OF SCIENCES.

ing effect of violet light, and came to the conclusion that there was
no evidence whatever to sustain the opinions of these experi-
menters. In 1839 he published a somewhat extended paper on the
use of a secondary wire as a measure of the relative tension of elec-
tric currents, describing the construction and use of a torsion gal-
vanometer and discussing a method of measuring electro-motive
force by the fall in the deflection when a wire of high resistance
was included in the circuit. He also considers in this paper the
relations of electro-motive force and of resistance to the current pro-
duced. In 1843 a paper on the law of the conducting power of
wires gave the results of his measurements made to solve the prob-
lem of transmitting electric impulses through long lengths of a
conductor, a research undertaken to aid his colleague, Professor
Morse, in perfecting his electro-magnetic telegraph. In this paper
the author shows that the diminution of the strength of an electric
current itself diminishes rapidly with increase of length in the wire,
and that generally the conducting effect of wires may be represented
by a logarithmic curve.

The purely chemical researches published by Dr. Draper were
also few in number. Among these may be mentioned his memoirs
on the analysis of certain ancient coins and medals (which seemed
to him to prove the possibility of diffusion in solids) on micro-chem-
istry, on the constitution of the atmosphere, on respiration, on the
allotropisrn of chlorine, on the existence and effects of allotropism
in the constituent elements of living beings, on a singular property
of gun-cotton mixture, and on a new method for the determination
of urea.

In 1844, in a volume on the forces which produce the organiza-
tion of plants, Dr. Draper published, as an appendix, the scientific
memoirs of his which had appeared up to that time bearing on this
question, and in 1873, in a book entitled " Scientific Memoirs," he
collected together the papers which he had published upon Radiant
Energy and closely allied subjects.

During the later years of his life Professor Draper devoted his
time much more largely to literary than to scientific work. Upon
his appointment to the chair of physiology in 1850 he turned his
attention once more to physiological subjects, and in 1856 he collected
together the matter which he had carefully elaborated in his class
lectures into his " Human Physiology, Statical and Dynamical."
This book marked a new departure in the science of physiology,

372

JOHN WILLIAM DRAPER.

since it contained not only the results of his valuable original in-
vestigations on various important subjects, illustrated by his own
admirable micro-photographs, but also clear and forcible discus-
sions of the applications of strictly scientific theory to a region
heretofore almost entirely given over to a hypothetical vital force.
"Among the new experiments and explorations which it contained
may be mentioned the condensing action of membranes, the cause
of the coagulation of the blood, the theory of the circulation of the
blood, the explanation of the flow of sap, the endosmotic action of
thin films, the measure of the force of endosmose, the respiration of
fishes, the action of the organic muscle-fibers of the lungs, the allot-
ropisrn of living systems, the action of the skin, the functions of the
nerve vesicles and their electrical analogies, the functions of the
sympathetic nerve, the explanation of certain parts of the auditory
apparatus, particularly of the cochlea and semicircular canals, the
theory of vision, and the theory of muscular contraction." This
treatise took at once a recognized rank as a text-book, both in this
and other countries, and was translated into several foreign lan-
guages, and even into Russian.

Perhaps it was quite natural that a philosophic mind like Draper's
should be led by these studies to formulate a sort of socialistic physi-
ology and to trace in the working of communities and nations the
same laws which control the evolution of the individual. But how-
ever this may be the " Physiology " was followed, in the course of
a few years, by what many have considered his most brilliant work,
"A History of the Intellectual Development of Europe," published
in 1863. " The object of this work was mainly to point out that
the intellectual progress of nations proceeds in the same course as
the intellectual development of the individual ; that the movement
of both is not fortuitous, but under the dominion of law ; that the
stages of personal development are paralleled by the stages of social
development, and, indeed, as paleontology has proved, by the evolu-
tion of all animated nature, and that there is an ascent of man
through well-marked epochs from the most barbarous to the most
highly civilized condition." In short it was designed to be an
argument in favor of evolution and the reign of law in the historical
development of the world. Few philosophical works have attained
to celebrity so quickly. It ran rapidly through many editions in
this country and was translated into nearly every European lan-
guage. The Westminster Review said of it : " It is one of the not

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NATIONAL ACADEMY OF SCIENCES.

least remarkable achievements in the progress of positive philosophy
that has yet been made in the English tongue — a noble and even
magnificent attempt to frame an induction of all the recorded phe-
nomena of European, Asiatic, and North African history. Unaccus-
tomed though a reader might be to scientific habits of thought or
uninterested in the gradual elaboration of eternal rules and princi-
ples, here he can at least disport himself amid noble galleries of
historic paintings and thrill again at the visions of the touching
epochs that go to fomi the drama of the mighty European past.
What Comte showed might and ought to be done for the whole world
of man; what Buckle commenced for England, Scotland, France
and Spain, Draper has effected for the whole of Europe. The
gigantic vastness of the task is almost paralyzing." So too the
Athenaeum : " It is no light commendation to say that its execution
is not altogether unequal to its magnitude. If it were equal the
world would place Dr. Draper on one of the very highest pinnacles of
intellectual achievements. His tenacity and completeness of grasp
makes itself felt for the most part on every page."

In 1864 the Historical Society of New York invited Dr. Draper
to deliver a course of four lectures upon some subject in gen-
eral political economy. These lectures were afterward expanded
and published the following year under the title, " Thoughts on the
Future Civil Policy of America." They treated : (1) on the influ-
ence of climate upon man ; (2) on the effects of emigration; (3) on
the political force of ideas, and (4) on the natural course of national
development. These lectures " contained discussions of several
interesting points which since that time have largely occupied pub-
lic attention, such as the internal emigration from the Atlantic
States to the West, the Asiatic emigration to the Pacific States, the
political effects of polygamy in Utah, the tendency of democratic
institutions to centralization, and a comparison of the European
with the American method of government."

The line of investigation thus entered upon resulted in his under-
taking a far more serious labor, the preparation of a " History of
the American Civil War," a work upon which he was almost con-
tinuously engaged for several years immediately following the close
of this war, and which appeared in three large volumes during the
years between 1867 and 1870. He had been urged to enter upon
this work by the earnest request of persons who had been chief
actors in the events described and who rendered him effective aid.

374

JOHN WILLIAM DKAl'ER.

Mr. Stanton, the Secretary of War, issued orders to the adjutant
general of the army of the United States to " furnish him copies of
all orders, reports, correspondence, telegraphic dispatches, or other
documents on file in the War Department as he might request, and
to permit him to inspect and have copies of any maps, plans, and
other papers necessary for the preparation of his work, and to fur-
nish him with statistical information respecting the armies of the
United States, their organization and operations." This order in-
cluded also all the Confederate archives in possession of the War
Department. Nor was the interest of the Secretary of War limited
to this. He supplied a large amount of personal information of the
utmost value. Access was not unfrequently given the author to
documents and correspondence of the most confidential kind, with
a view of guiding him to correct conclusions ; and many of the most
decisive military operations are detailed from private memoranda
furnished by the commanding officers themselves.

The last literary work on which Dr. Draper was engaged was the
" History of the Conflict between Religion and Science," issued in
1874 as one of the volumes of the International Scientific series.
Much of the material utilized in this volume is said to have been
matter originally intended for the " Intellectual Development of
Europe." The book attempted to trace the development of the an-
tagonism which has ever been present between the conservative and *
the scientific elements of thought, between the ecclesiastical and old
on the one side and the radical and new on the other. The former,
always opposed to the progress of the latter, has sought in all times
to hinder this progress by every means it could devise lest forsooth
some of its antiquated tenets should require modification. The title
of the book has sometimes been criticised on the ground that relig-
ion is a personal element entirely, and with this, of course, science
can never be in antagonism. But using the word in the broader
sense, in which Dr. Draper used it — as synonymous with ecclesiasti-
cism and theology — there always has been a conflict between them
and there always will be so long as they both shall exist. The
favor with which this book was received was something surprising.
In the first ten years of its existence it passed through more than
twenty editions in the English language and was translated into
French, Spanish, German, Dutch, Russian, Italian, Portuguese,
Polish, and Servian. It has even been placed on the Index Ex-
purgatorius of the Romish church, an honor which its author has

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shared with Galileo, with Copernicus, with Kepler, with Locke, and
with Mill.

In all his literary work Dr. Draper's methods were always of the
same high character as those which distinguished his scientific in-
vestigations. He showed alike in both the same close and impartial
scrutiny of the facts, the same careful and minute examination of
all the conditions which they involved, the same conscientious and
exact record of the results obtained. After passing the ordeal of
his severe criticism his work had little to fear from outside attack.
All that he did was pervaded by the high moral tone which char-
acterized the man. If he was scrupulously accurate in observing
and testing his facts and in drawing inferences from them, if he
was ingenious in devising and skillful in applying crucial tests to
detect error or misconception, he was equally honest in placing his
observations and conclusions on record and in according to his con-
temporaries and co-workers the full share of praise to which they
were entitled.

It is not easy to estimate the value of Dr. Draper's services as a
teacher. From the time of his appointment to the professorship in
Hampden Sidney College in 1836 until the year before his death—
a period of forty-five years — he was constantly occupied in the
work of instruction. Of the facilities at his disposal when he first
went to New York he thus speaks : " Our laboratory was then in a
little dark back room without ventilation. The morning sun strug-
gled almost in vain to see what we were doing, for the window-
panes were covered with an incongruous arrangement of Venetian
blinds and Gothic mullions. A hole in the ceiling led up to the
chapel above, to the pulpit of which the material for the daily
lecture was carried in a tea-tray. I called it a pulpit, because they
used to preach out of it. A clergyman, who also statedly occupied
it, regarded it as a pneumatic trough, because I experimented in it.
And this, I think, it really was, for, recalling the Greek etymology
of that epithet, it plainly indicates the double function, spiritual
as well as chemical. Our laboratory work commenced at seven in
the morning and continued uninterruptedly till after midnight, and,
as might have been leadily foreseen, what, with the impure air and
mental application, the individual chiefly engaged twice contracted
a fever and narrowly escaped with his life." Dnring the ten years
from 1840 to 1850 he gave a series of introductory lectures to the
medical classes in the university, which are among the best popular

376

JOHN WILLIAM DRAPER.

expositions of the applications of science to medicine to be found
in the language. These, as well as his valedictory lectures, were
generally printed by the classes to which they were severally ad-
dressed. According to competent authority they were " clear in
statement, fresh and striking in their views, and lively, poetic, and
witty, as well as instructive, well fitted to awaken the students' en-
thusiasm." Those on the relations of chemistry to medicine, on the
history of chemistry, on atmospheric air, on water, on oxygen, and
on phosphorus are spoken of as having been exceptionally sugges-
tive and brilliant.

Dr. Draper appeared but rarely upon the platform of the public
lecturer. In 1853 he made an address before the Alumni Associa-
tion upon "The Indebtedness of the City of New York to its Uni-
versity," which was a strong plea for science in education. In 1863
he gave the anniversary discourse before the New York Academy
of Medicine, the subject of which was " The Historical Influence of
the Medical Profession." His lectures before the Historical Society
in 1864 have already been mentioned. As president he addressed
the American Union Academy at its first annual meeting in 1870.
His felicitous address at the farewell dinner to Professor Tyndall,
given in New York in February, 1873, and his inaugural address
as president of the American Chemical Society on "Science in
America," delivered in 1876, are among his happiest efforts. One
of the most noteworthy of his public addresses was that upon Evo-
lution, delivered before the Unitarian Institute, in Springfield, in
October, 1877.

Besides the work which Dr. Draper did in pure science he was
closely connected with the development of two of the most impor-
tant inventions ever made. One of these was the electro-magnetic
telegraph of Morse, the other was the art of photography. In one
of his addresses to the alumni (1853) he gives the following account of
the evolution of the telegraph: "Fourteen years ago there stood
upon the floor of the chemical laboratory of our University a pair of
old-fashioned galvanic batteries. Like the cradle of a baby, they
worked upon rockers, that so the acid might be turned on or off.
A gray-haired gentleman had been using them for many years to
see whether he could produce enough magnetism in a piece of iron
at a distance, to move a pencil and make marks upon paper. He
had contrived a brass instrument that had keys something like a
piano in miniature, only there was engraven on each a letter of the

377

NATIONAL ACADEMY OF SCIENCES.

alphabet. When these were touched the influence of the batteries
was sent through a copper wire and a mark answering to a letter
was made a long way off. * * * But long after the telegraphic
instruments were perfected it was doubtful whether intelligence
could be sent to any considerable distance. It is one thing to send
an electric current a few yards and a totally different affair to send
it a thousand miles. Experiments which had been made under the
auspices of the Russian government by Professor Jacobi, of the
University of Dorpat, had led to the inference that the law of the
conducting power of wires, originally discovered in Germany, was
correct ; and, in addition, a corroborative memoir had been read by
Lenz before the Imperial Academy of Sciences at St. Petersburg.
At this time so little was known in England as regards this impor-
tant point, that some of the most eminent natural philosophers con-
nected with universities there embraced the opposite view. I may
not be able to make the precise point in dispute clear; it was this :
A current passing through a certain length of wire suffers a certain
amount of loss. If it should go through a wire a thousand times
as long will the loss be a thousand times as great ? The Russians
said yes ; the English said no. If the former was the case it was
universally concluded that the electric telegraph would not be prac-
ticable for any considerable distance. A series of experiments was
made in the University of New York which established beyond all
question the truth of the Russian view. But at that time the higher
mathematics were cultivated in our laboratory, as well as mere ex-
perimenting ; and on submitting the results to such a mathematical
discussion the paradoxical conclusion was brought out that it is a
necessary consequence of that law that after a certain length of
wire has been used the losses become imperceptible. Encouraged
by this, a party of gentlemen went with the inventor of the telegraph
to a rope-walk near Bloomingdale, one summer morning, and there
tested the truth of these conclusions on lengths of wire varying from
one to some hundreds of miles. The losses of the currents were
measured by the quantity of gas set free in the decomposition of
water. The result was completely successful, and telegraphing for
any distance became an established certainty."

The part which he took in the evolution of photography he thus
describes : ** When the French government, in 1839, purchased of
Daguerre his invention of photogenic drawing, its applications were
very limited. The process was adapted to interiors, statuary, and

378

JOHN WILLIAM DRAPER.

architectural subjects, but wholly unsuited to landscape scenery or
to portraits. The inventor himself had made attempts at applying
it to the taking of likenesses, but had given it up in despair. Soon
after the publication of Daguerre's invention in America a series
of experiments was conducted in our laboratory with a view of de-
termining whether the difficulties could be removed." The results
were successful, and the taking of portraits from life by daguerreo-
type became before long an everyday operation.

The great value of Dr. Draper's contributions to science has been
cordially recognized by the highest authorities. Melloni, the creator,
as it were, of the science of radiant heat, warmly congratulated him
on his memoir on this subject, presented an abstract of it to the
Royal Academy of Sciences at Naples, and in his own subsequent
memoir warmly commends the ingenuity and ability of the Amer-
ican scientist. Herschel was equally cordial in praise of his photo-
chemical researches. Berzelius, a few days before his death, sent
to Dr. Draper his portrait with a kind message conveying his ap-
preciation of what he had done for science. Kirchhoff, in 1862,
thus speaks of his heat experiments : " Draper has derived from ex-
periment the conclusion that all solid bodies begin to glow at the
same temperature, but he has observed in his experiments that cer-
tain bodies, as chalk, marble, and fluor-spar, shine at a lower tem-
perature than they should according to this law; he calls this light
phosphorescent and observes that it is distinguished from the glow
by its color. But whatever name may be given to the light it con-
tradicts the law, and a body which shows it cannot satisfy the as-
sumption which is made in proving the law ; it cannot remain un-
changed, the temperature remaining the same ; the phosphoresence
is not the simple influence of heat, it is not exclusively conditioned
on temperature, but it is caused by changes in the body ; if these
changes, be they chemical or of any other kind, cease, then the
phosphoresence must also vanish." Bunsen and Roscoe have recog-
nized Dr. Draper most fully as the pioneer in the investigation of
the action of light upon chlorine, a subject worked out successfully
by them.

Dr. Draper was elected a member of many of the learned societies
of Europe, among them the Accademia dei Lincei, at Rome, and
the Physical Society of London. In 1843 he was elected a member
of the American Philosophical Society at Philadelphia, and in
1860 he received the degree of LL. D. from the college of New

379

NATIONAL ACADEMY OF SCIENCES.

Jersey at PrincetoD. In 1875 the American Academy of Arts
and Sciences at Boston awarded to him the Rumford medals for
his reseaches on Radiant Energy. In his speech of presentation
the Hon. Charles Francis Adams, then president of the Academy,
after recapitulating the reasons given by the committee for recom-
mending this award, said to Mr. Quincy, who was deputed in Dr.
Draper's absence to receive the medals : " I pray you, in receiving
these two medals on his behalf, in accordance with the terms of the
original trust, to assure him on the part of the Academy of the high
satisfaction taken by all its Fellows in doing honor to those who,
like him, take a prominent rank in the advance of science through-
out the world." In his letter of reply Dr. Draper says : " Your
favorable appreciation of my researches on radiation, expressed to-
day by the award of the Rumford medals — the highest testimonial
of approbation that American science has to bestow on those who
have devoted themselves to the enlargement of knowledge — is to
me a most acceptable return for the attention I have given to that
subject through a period of more than forty years. * * * It
adds impressively to the honor you have this day day conferred on
me that your action is the deliberate determination of competent,
severe, impartial judges. I cannot adequately express my feelings
of gratitude in such a presence, publicly pronouncing its approval
of what I have done."

Professor Draper was not elected a member of the National
Academy of Sciences until 1877. It is not easy to understand at
this late day why a man so eminent in science was not included
among the original incorporators of the Academy. An attempt, it
is believed, was made to remedy this apparent oversight during the
meeting which was held in New York in 1863 for organization, but
for some unexplained reason the effort failed. So uncalled for an
action on the part of the Academy rendered it for some time doubt-
ful whether he would accept the membership when it was subse-
quently tendered.

Dr. Draper was married at quite an early age. While a student
at the University of London in the year 1830, then nineteen years
old, he boarded with a friend of his father's, Mrs. Barker by name,
where he met her niece, Miss Antonia Gardner, who was then
residing with her and attending a young ladies' school in the
neighborhood. This young lady was the daughter of Dr. Gardner,
of Rio Janeiro, the attending physician of the Emperor of Brazil,

JOHN WILLIAM DRAPER.

Dom Pedro I. Though himself an Englishman Dr Gardner
had married into the celebrated de Piva-Pereira family of Portu-
gal, and this, their only daughter, had been brought to London
to complete her education. Within a few months they became
engaged, and in 1831, not long after the death of her father, in
Brazil, they were married. In 1832 Dr. Draper's father also died,
and his mother accompanied the newly-married couple across
the ocean to settle among the little Wesleyan colony in Vir-
ginia, where she died in the following year. It was to his ac-
complished wife that Dr. Draper owed much of the happiness
which characterized his married life. Six children were born to
them, one of whom died in infancy. The eldest son, John Chris-
topher Draper, was born in Virginia in 1835 and became his
father's successor as professor of chemistry in the medical de-
partment of the University of New York. He died on the 20th of
December, 1885. The second son, Henry Draper, was born in 1837
also in Virginia. He became professor of physiology in the univer-
sity and subsequently professor of analytical chemistry. He early
turned his attention in the direction of physical research, especially
in its application to astronomy, and was elected a member of
the National Academy in 1877. His early death in 1882 alone
prevented his rising to an equal eminence as an investigator
with that attained by his distinguished father. The third son,
Daniel Draper, is at present the director of the Meteorological Ob-
servatory in Central Park, New York. Dr. Draper's daughters
were Virginia, afterward Mrs. Maury, named for the State in which
she was born, who died in October, 1885, leaving three children ;
and Antonia, who is at present Mrs. Edward H. Dixon.

Any record of the Draper family, however, which did not men-
tion Dr. Draper's elder sister Catherine would be quite incomplete.
As already mentioned, she accompanied the newly-married couple
across the ocean when they removed to America. Having shared
her brother's tastes for scientific studies, she became his assistant in
research and rendered him most valuable aid. Her portrait was
the first ever taken from the life by the daguerreotype process, and
the colored plates which illustrate his memoirs were the work of
her pencil. She was a constant inmate in his family, and during
the many years of Mrs. Draper's ill health she was as a mother to
the children. She has outlived her brother, and resides still at the
family mansion in Hastings.

(3) 381

NATIONAL ACADEMY OF SCIENCES.

On coming to New York Dr. Draper occupied at first a house
in Charles street, subsequently removing to the corner of Broad-
way and Amity street. But in 1848 he purchased a delightfully
located piece of property at Hastings upon the Hudson, where he
lived until his death. It was here that Henry Draper built his
observatory ; and in this building the father and son spent many a
pleasant hour together engaged in that most delightful of occupa-
tions, the pursuit of scientific knowledge.

Dr. Draper, though somewhat below the average stature, was a
man of fine personal presence. He was mild in manner and quiet
in demeanor, having very little of self-assertion. The excellence of
his disposition and the charm of his personal intercourse drew to
him warm and disinterested friends on every hand. He was an
extensive reader and his conversational powers were remarkably
developed, so that he always had attentive listeners, whether the
subject of his discourse was literary or scientific. But it was when
he opened his rich storehouse of personal reminiscence that his
auditor was most charmed and delighted. His health, which through
life had been generally good, was disturbed during his later years by
severe attacks of gravel, which incapacitated him for journeying.
These attacks wore upon him and finally ended his life. He died
at Hastings, on the 4th of January, 1882, and was buried at Green-
wood.

In the eloquent words of Professor Lovering, " Dr. Draper's mind
was too large to be shut up within the walls of his laboratory. To
him the minutest facts were of value, but only as they furnished the
key for interpreting the Universal Cosmos of nature and humanity.
In clear and graceful language the best that was in his thoughts
was shared by the world. There was a continuity in his life-work,
plain to himself, if not obvious to the superficial observer. He says :
' When I thus look back on the subjects that have occupied my
attention I recognize how they have been interconnected, each pre-
paring the way for its successor. Is it not true that for every person
the course of life is along the line of least resistance, and that in
this the movement of humanity is like the movement of material
bodies?'"

382

PUBLICATIONS OF JOHN WILLIAM DRAPER.

I.— SCIENTIFIC MEMOIRS.

1832.

On volcanoes. By W. M. Higgins and J. W. Draper. Mai/. X«f. Hist.,
v, 104-174, 2(52-272, 6:J2-OJ}7 ; vi, 344-350, 1832.

Remarks on the formation of the Dead Sea and the surrounding district.
I5y W. M. Higgins and J. W. Draper. May. Mif. ///'.s^., v, 532-534, 1832.

1833.

Remarks on electrical decompositions. By William M. Higgins, F. G. S.,
and ,}. W. Draper (dated 110 Chancery Lane, August, 1832). Edinb. New
Phil. Juurn., xiv, 314-317, April, 1833.

1834.

Influence of electricity on capillary attraction. (Extract of a letter from
Jno. W. Draper to the editor, dated Christiansville, Mecklenburg, Va., May
31st, 1832*.) Am. J. Sci., I, xxvi, 399, July, 1834.

Some experimental researches to determine the nature of capillary attrac-
tion. J. Fr. Inst, xiv, 147-105, September, 1834.

An account of some experiments made to determine the best construction
of galvanic batteries of four elements. J. Fr. Inst., xiv, 289-295, Novem-
ber^ 1834.

Chemical analysis of native chloride of carbon. J. Fr. Inst., xiv, 295-298,
November, 1834.

1835.

Experiments to determine whether light exerts magnetic action. J. Fr.
Inst., xv, 79-85, 155-158, February. March, 1835.

Idolatry and philosophy of the Zabians. Am. J. Sci., I, xxviii, 201, July,
1835.

On the chemical analysis of coins and medals. Am. J. Sci., xxix, 157-160,
October, 1835. (Bibliotheyue Universelle 1835, 370-374. Froriep Notl-
zen, xlix, 7-9.)

1836.

On the tidal motions of conductors free to move. J. Fr. Inst., xvii, 27-33,
January, 1830.

Experiments on absorption. Am. J. Med. Sci., xviii, 13-32, May, 1836.

Experiments on endosmosis. ,/. Fr. Inst., xvii, 177-182; xviii, 27-31,
March, July, 1830. (Phil. Mag., Ill, xi, 559, December, 1837.)

Observations on microscopic chemistry. J. Fr Inst., xviii, 378, Decem-
ber, 1836.

* This must be a misprint for ls:H, since at this date, in 1832, Draper had not yet left
England.

383

NATIONAL ACADEMY OF SCIENCES.

1837.

Experiments on solar light. Am. J Mcd. Sei., xx, 208, May, 1837; J.
Fr. Inst., xix, 409-479, June ; xx, 38-46, July ; 114-121, August : 250-255,
October, 1837. (Sturgeon'1 s Ann. Elcc., ii, 397-399, 1838.)

liemurks on the action of presence. Am. ,/. Mnl. ,SV/., xxi, 123-130, No-
vember, 1837. (Froriep Nottzen, II, v, 257-250, 1839.)

1838.

Simultaneous meteorological observations. J. Fr. Inst., xxi, 39, Janu-
ary, 1838.

On the physical action of capillary systems. Identification of the force
producing motion with the chemical force (dated November 20, 1837). Am.
J. Mf.d. Set., xxi, 289-302, February, 1838.

On some mechanical functions of areolar tissues. Containing the co-ordi-
nation of the diffusion laws of Professor Graham and the experiments of
Dr. J. K. Mitchell and the general laws of equilibrium. Am. J. Med. Set.,
xxii, 23-44, May; 302-323, August, 1838.

Remarks on the constitution of the atmosphere. Phil. Mat/., Ill, xxii,
241-252, October, 1838.

1839.

Further remarks on the action of presence. Am. J. Med. Sei., xxiii,
08-81, September, 1839.

On the use of a secondary wire as a measure of the relative tension of
electric currents. Phil. Mag., Ill, xv, 200-279, October; 339-349, Novem-
ber, 1839. (Bibliotheque Universelle, xxiv, 170-179, 1840.)

1840.

An account of some experiments made in the south of Virginia on the
light of the sun. Phil. Mag., Ill, xvi, 81-84, February, 1840. (Froriep
Notizen, II, xili, 337-341.)

On the electromotive power of heat. Pldl. Mag., Ill, xvi, 451-401,
June, 1840.

On the process of daguerreotype and its application to taking portraits
from the life. Pldl. Mag , III, xvi* 535, June; xvii, 217, September, 1840.
(Sturgeon's Ann. Elec., vi, 503-504.)

1841.

On some analogies between the phenomena of the chemical rays and those
of radiant heat. Pldl. Mag., III., xix, 195-210, September, 1841.

1842.

On certain spectral appearances and on the discovery of latent light.
Phil, Mag., Ill, xxi, 348-350, November, 1842. Am. J. Sci., I, xliv, 202,
October- December, 1842.

On a new imponderable substance and on a class of chemical rays anal-
ogous to the rays of dark heat. Phil. Mag., Ill, xxi, 453-461, December,
1S42. (Froriep Notizen, II, xxv, 1-8, 17-23, 1843.)

384

JOHN WILLIAM DKAPEK.

1843.

On the rapid detithoni/ing ])owor of certain gases and vapors, and on an
instantaneous means of producing spectral appearances. Phil. Mm/., Ill,
xxii, 101-105, March, 1K43. (Sturyeon'x Ann. Elcc., x, 402-4(55. Frorirp
ATo/;-r/,, II, xxv, :J40-:J43, 1843.)

On a new system of inactive tithonographic spaces in the solar spectrum
analogous to the fixed lines of Fraunhofer. Phil. May., III, xxii, 300-364,
May, 1843.

On the tithonotype, or art of multiplying daguerreotypes. Phil. May.,
Ill, xxii, 305, May, 1843.

On the decomposition of carbonic-acid gas and the alkaline carbonates by
the light of the sun, and on the tithonotype. Proc. An/. Phil. Soc., iii, 111-
114, May, 1843. Phil. Mat/., Ill, xxiii, 161-170, September, 1843. (Rep.
Jirif. Axxoc., 1843, Pt. 2, 33-34; Chemist, 1843, iv, 444-445 ; Am. J. Sri.,
I, xlvi, :5!)8, 1844; Ann. <1hu», /%*., xi, 214-228, 1844; J. Pr. Ckem., xxxi,
21-30, 1844; Napoli Rendi Conto, iii, 297-300, 1844.)

On the law of the conducting power of wires. Am. J. Sci., I, xlv, 392,
.July-September, 1843 (Arc/do, de I'Elec., vi, 329-330, 1844).

On a change produced by exposure to the beams of the sun in the proper-
ties-of an elementary substance. Rep. Brit. Assoc., 1843, Pt. 2, 9. Phil.
Ma;/., Ill, xxiii, 388, November, 1843. (Chemist, iv, 442-443, 1843; Am.
J. ,SW,, I, xlvi, 390, January-March, 1844.)

Description of the tithonometer [chlorhydrogen photometer] ; an instru-
ment for measuring the chemical force of the indigo-tithonic rays. Phil.
May., Ill, xxiii, 401-405, December, 1843; Am. J. Sci., I. xlvi, 217-232,
January-March, 1844.

1844.

On Mr. Hunt's book entitled "Researches on Light." Phil. May., Ill,
xxv, 49, July, 1844.

On tithonizcd chlorine. (Read at the meeting of the British Association
in Cork in 1843.) Phil. May., Ill, xxv, 1-10, July, 1844.

Further considerations on the existence of a fourth imponderable. Phil.
Ma,/., Ill, xxv, 103-110, August, 1844.

Note on the decomposition of carbonic acid by the leaves of plants under
the influence of yellow light. Phil. May., Ill, xxv, 169-173, September,
1844.

1845.

Is capillary action an electrical phenomenon? Phil. May., Ill, xxvi,
185-189, March, 1845.

On the interference spectrum and the absorption of the tithonic rays.
Phil. Mm/., Ill, xxvi, 405-478, June, 1845.

On the allotropism of chlorine as connected with the theory of substitu-
tions. Am. J. Sci.., I, xlix, 340-308, July-September, 1845. Phil. Ma,,.,
Ill, xxvii, 327-340, November, 1845. (Kibl. Universelle, Ix, 305-379, 1845;
J. Pr. Chem., xxxvii, 103-109, 1840; J. Pharm., ix, 398-399, 1840.)

385

NATIONAL ACADEMY OF SCIENCES.

Account of a remarkable difference between the rays of incandescent lime
and those emitted by an electric spark. Phil. Mag., Ill, xxvii, 435-437,
December, 1845.

1846.

On the cause of the circulation of the blood. Phil. May., Ill, xxviii,
178-189, March, 1840 ; Am. J. ScL, II, ii, 276-279, September, 1846. (Fro-
riep Notizen, II, xxxvii, 289-296, 305-311.)

1847.

Kemarks on the existerce and mechanism of the protecting or negative
rays of the sun. Phil. Mag., Ill, xxx, 87-93, February, 1847. (Biblio-
theque Universelle. v, 5-14, 1847; J. de Pharm., xii, 152-154, 1847.)

Singular property of gun-cotton mixture. Phil. Mag., Ill, xxx, 299,
April, 1847.

On the production of light by heat. Phil. Mag., Ill, xxx, 345-360, May,
1847 ; Am. J. ScL, II, iv, 388-402, November, 1847. (Froriep Notizen, III,
iv, 97-102, 113-119, 1847.)

1848.

On the production of light by chemical action. Phil. Mag., Ill, xxxii,
100-114, February, 1848; Am. J. ScL, II, v, 159-172, March, 1848. (Fro-
riep Notizen, III, vii, 17-24, 33-37, 1848.)

1849.

On the existence and effects of allotropism in the constituent elements of
living beings. Phil. Mag., Ill, xxxiv, 241-246, April, 1849.

1851.

On the phosphorescence of bodies. Phil. Mag., IV, i, 81-100, February,
1851.

On the chemical action of light. Phil. Mag., IV, i, 368-393, May, 1851.
(J. de Pharm., xx, 253-258, 1851.)

1852.
On respiration. Am. J. Med. ScL, II, xxiii, 314-320, January, 1852.

1853.

On a new method for the determination of urea. Phil. Mag., IV, vi, 290-
292, October, 1853.

1857.

On the diffraction spectrum. Phil. Mag., IV, xiii, 153-156, March, 1857.

On the measurement of the chemical action of light. Phil. Mag., IV,
xiv, 161-164, September, 1857. (J. Phot. Soc., iv, 34-36, 1858.)

On the influence of light upon chlorine and some remarks on alchemy.
Phil. Mag., IV, xiv, 321, November, 1857.

1858.

On the nature of flame and on the condition of the sun's surface. Phil.
M<KJ., IV, xv, 90-93, February, 1858; Am. J. ScL, II, xxvi, 268-271, Sep-
tember, 1858.

386

JOHN WILLIAM DRAPER.

1863.

On the motions of camphor toward the light. Phil. Mag., IV, xxv, 38,
January, 18G3.

On the motions of camphor toward the light and on variations in the fixed
lines of the solar spectrum. Phil. Mag., IV, xxv, 342-344, May, 1803.

1872.

Researches in actino-chemistry. Memoir first. On the distribution of lieat
in the spectrum. Phil. Mag., IV, xliv, 104-117, August, 1872 ; Am. J. Sc.i.,
Ill, iv, 101-175, September, 1872.

Researches in actino-chemistry. Memoir second. On the distribution of
chemical force in the spectrum. Phil. Mag., IV, xliv, 422-443, December,
1872; Am. J. Sci., Ill, v, 25-38, January, 91-98, February, 1873.

1877.

On the fixed lines in the ultra-red invisible region of the spectrum. Phil.
M<I<I., V, iii, 8G-88, February, 1877.

1879.

Political effect of the decline of faith in Continental Europe. Princeton
Review, January, 1879.

On a new form of spectrometer and on the distribution of the intensity of
light in the spectrum. Am. J. Sci., Ill, xviii, 30-35, July, 1879 ; Phil. Mag. ,
V, viii, 75-81, July, 1879.

1880.

On a new standard of light. Phil. Mag., V, ix, 76, January, 1880.

On the phosphorograph of a solar spectrum and on the lines in its infra-
red region. Proc. Am. Ac.ad., xvi, 223, December, 1880; Am. J. Sci, III,
xxi, 171-183, March, 1881 ; Phil. Mag., V, xi, 157-109, March, 1881.

II.— BOOKS.

Elements of chemistry. By Robert Kane. American edition edited by
John William Draper. One volume, 8vo., pp. 704, New York, 1842.

A treatise on the forces which produce the organization of plants, with an
appendix. One volume, 4to., pp. 108, 216, New York, 1844.

Text-book on chemistry. One volume, 12mo., pp. 412, New York, 1840.

Text-book on natural philosophy. One volume, 12mo., pp. 381, New
York, 1847.

Human physiology — statical and dynamical. One volume, 8vo., pp. 649,
New York, 1856.

History of the intellectual development of Europe. One volume, 8vo.,
pp. 631, New York, 1862.

Thoughts on the future civil policy of America. One volume, 8vo., pp.
325, New York, 1865.

A text-book on physiology. One volume, 12 mo., pp. 376, New York, 1800.

History of the American civil war. Three volumes, 8vo., pp. 567, 014,
701, New York, 1867-1870.

387

NATIONAL ACADEMY OF SCIENCES.

History of the conflict between religion and science. One volume, 12mo.,
pp. 373, New York, 1874.

Scientific memoirs ; being experimental contributions to a knowledge of
radiant energy. One volume, 8vo., pp. 473, New York, 1878.

III.- LECTURES AND ADDRESSES.

On the relations of chemistry to medicine. A lecture introductory to the
course in chemistry, University of New York, medical department. De-
livered November 1, 1841. 35 pages.

On the theory and phenomena of heat. The concluding lecture of that
part of the chemical course in the medical department of the University of
New York. Delivered by Professor J. W. Draper, November 22d, 1841.
10 pages.

A valedictory lecture. Delivered in March, 1842. 14 pages.

On the relations of atmospheric air to animals and plants. A lecture in-
troductory to the course on chemistry, medical department, University of
New York. Delivered October, 1844. 10 pages.

On the relations and nature of water. Introductor}^ lecture to the course
on chemistry, medical department. Delivered November 1, 1845. 15 pages.

On the history of chemistry. An introductory lecture to the chemical
course, medical department. Delivered October 30, 1840. 15 pages.

On phosphorus. An introductory lecture to the chemical course, medi-
cal department. Delivered October 30, 1847. 14 pages.

On oxygen gas. An introductory lecture to the course in chemistry,
medical department. Delivered October, 1848. 15 pages.

The influence of physical agents on life. An introductory lecture to the
course on chemistry and physiology, medical department. Delivered Octo-
tober, 1850. 14 pages.

The indebtedness of the city of New York to its university. An address
to the alumni at their twenty-first anniversary, held on the 28th of June,
1853. 30 pages.

The historical influence of the medical profession. An anniversary dis-
course. Delivered before the New York Academy of Medicine, December
10, 1803. 32 pages.

Professional education. A lecture introductory to the course of 1809- '70
in the medical department. Delivered October 18, 1809. 10 pages.

Address delivered to the American Union Academy of Literature, Science,
and Art at its first annual meeting, January 31, 1870. By J. W. Draper,
president. 24 pages.

Science in America. An inaugural address before the American Chemi-
cal Society. By Dr. John W. Draper, president. Delivered November 10,
1876. (American Chcndxt, December, 1876; Am. J. Sci., Ill, xiii, 01-07,
January, 1877.)

Evolution — its origin, progress, and consequences. An address to the
Unitarian Institute at Springfield, Mass., October 11, 1877. Popular Science
Monthly, December, 1877.

THE UNIVERSITY LIBRARY

UNIVERSITY OF CALIFORNIA, SANTA CRUZ

SCIENCE LIBRARY

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