Popular Science Monthly/Volume 4/January 1874/Sketch of Dr. J. W. Draper

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THE period from 1830 to 1870 is very strikingly marked in the history of science. It opens with great discoveries in electricity, and closes with very brilliant ones in light. Its middle portion is illustrated by the application of chemistry to physiology, which led to a revolution in the latter science, and indeed changed the face of medicine. It is adorned with many great inventions, such as photography, the electric telegraph, the construction of railways, and ocean steam navigation. The great wars it has witnessed, the Franco-Italian, the Crimean, the Prusso-Austrian, the Prusso-French, and the American Civil War, have occasioned, as all great wars inevitably do, much intellectual activity and profound social changes. Among the latter are the emancipation of the vast serf population of Russia, and of four million slaves in America. But, perhaps, most important of all—partly through the increase and diffusion of knowledge, partly through more rapid and incessant national intercommunication—ideas liberal in politics and elevated in religion have asserted their sway.

The generation that lived in this period has therefore fairly performed its share in the promotion of modern civilization. There is no European nation which has not participated in this great movement—none that cannot offer a list of the names of its people who may lay claim to a part of the honor of the success. In this respect America is not behind others—she too has done her share, both as regards science and industrial inventions. Among those of her citizens who have devoted their lives to these objects, and who by their successful pursuit have done honor to the country, and won for themselves an eminent name in the world of science, is the subject of our present sketch, John William Draper.

He was born at St. Helen's, near Liverpool, in 1811, and received his education for the most part from private instructors. At eleven years of age he was sent to one of the public schools of the Wesleyan Methodists, of which denomination his father was a minister. He remained there, however, only two years, and was then returned to private instruction. When the University of London was opened, he was sent there to study chemistry under Dr. Turner, at that time the most celebrated of English chemists. At the instance of several of his American relatives, he came to America, and completed his medical education at the University of Pennsylvania, graduating in 1836 with so much distinction that his inaugural thesis received the unusual compliment of being published by the faculty of that university. Shortly afterward he was appointed Professor of Chemistry in Hampden Sidney College, Virginia, and in 1839 received an appointment to the same professorship in the University of New York, with which institution he has ever since been connected.

Dr. Draper's earliest scientific publications were on the chemical action of light, a subject at that time almost completely neglected. Eventually he published in American and foreign journals, or read before scientific societies, nearly forty memoirs in relation to it. It would be impossible in this short sketch to give an enumeration of the facts contained in these papers. We shall, therefore, select only a few of the more prominent ones for remark.

Of all the chemical actions of light, by far the most important is that of the decomposition of carbonic acid by the leaves of plants, under the influence of sunshine. On this the whole vegetable world depends for its growth, and the whole animal world, directly or indirectly, for its food. The decomposition in question is essentially a deoxidation, and up to about 1840 it was generally supposed to be due to the violet rays of the spectrum, which, in accordance with the views held at that time, were regarded as producing deoxidizing actions, and were consequently known as deoxidizing rays. But this was altogether an assumption unsupported by experimental proof. Prof. Draper saw that there was but one method for the absolute solution of the problem, and that was by causing the decomposition to take place in the spectrum itself. In this delicate and beautiful experiment he succeeded, and found that the decomposition was brought about by the yellow rays, at a maximum by those in the vicinity of the Fraunhofer fixed line d, and that the violet rays might be considered as altogether inoperative. The memoir containing this result was first read before the American Philosophical Society, in Philadelphia, and immediately republished in London, Paris, and Berlin. It excited general interest among chemists. Even up to the present year it has furnished to the German experimenters the basis of a very interesting discussion in photo-chemistry.

In 1842 Dr. Draper discovered that not only might the Fraunhofer fixed lines in the spectrum be photographed, but that there exists a vast number of others beyond the violet, which up to that time had been unknown. He also found three great lines less refrangible than the red, in a region altogether invisible to the eye. Of these new lines, which more than doubled in number those of Fraunhofer, he published engravings. He also invented an instrument for measuring the chemical force of light—the chlor-hydrogen photometer. This was subsequently extensively used by Bunsen and Roscoe in their photo-chemical researches. In their paper, read before the Royal Society, in 1856, they say, "With this instrument Draper succeeded in establishing experimentally some of the most important relations of the chemical action of light."

Most of the papers he had written up to 1844 were in that year collected and published together, in a book bearing the title of a treatise on "the Forces producing the Organization of Plants." In this there are a great many experiments on capillary attraction, the flow of sap, endosmosis, the influence of yellow light on plants, etc.

His memoir "On the Production of Light by Heat," published in 1847, was an important contribution to spectrum analysis; among other things it gave the means for determining the solid or gaseous condition of the sun, the stars, and the nebulæ. In this paper he established experimentally that all solid substances, and probably liquids, become incandescent at the same temperature; that the thermometric point at which such substances are red-hot is about 977° Fahr.; that the spectrum of an incandescent solid is continuous, it contains neither bright nor dark fixed lines; that from common temperatures up to 977° Fahr. the rays emitted by a solid are invisible, but at that temperature they impress the eye with the sensation of red; that the heat of the incandescing body being made continuously to rise, other rays are added, increasing in refrangibility as the temperature ascends; and that, while the addition of rays so much the more refrangible as the temperature is higher is taking place, there is an augmentation in the intensity of those already existing.

This memoir was published in both American and European journals. An analysis of it was read in Italian before the Royal Academy at Naples, July, 1847, by Melloni, which was also translated into French and English.

But, thirteen years subsequently, M. Kirchhoff published, in a very celebrated memoir, considered by many as the origin of spectrum analysis, and of which an English translation may be found in the London and Edinburgh Philosophical Magazine, July, 1860, the same facts under the guise of mathematical deductions, with so meagre a reference to what Draper had done that he secured the entire credit of these discoveries. In an historical sketch of spectrum analysis subsequently published, Kirchhoff avoided all mention of his American predecessor.

Dr. Draper was the first person who succeeded in taking portraits of the human face by photography. This was in 1839. He published a minute account of the process at a time when in Europe it was regarded as altogether impracticable. He also was the first to take photographs of the moon, and presented specimens of them to the New York Lyceum of Natural History, in 1840.

In 1841 the University of New York established its medical college, Dr. Draper being appointed Professor of Chemistry in it. A very great change in medical studies and teaching was at that time impending. The application of chemistry to physiology was about to be made by Liebig and his school. In these new views Dr. Draper completely coincided, and therefore soon afterward physiology was added to his chair. He now resumed his early chemico-physiological researches, and eventually published the result of them in "A Treatise on Human Physiology, Statical and Dynamical." This work at once became a standard text-book in American colleges. It has passed through a great many editions, and was translated into several foreign languages. The Russian edition is used in the higher schools of that country.

It is impossible in our limited space to give an adequate account of the new facts and the important views, founded on extensive and expensive series of experiments, contained in this work. Among them, however, we may mention, an explanation of the selecting action of membranes; electrical theory of capillary attraction; cause of the coagulation of the blood; theory of the circulation of the blood; explanation of the flow of sap in plants; endosmosis of gases through thin films; measure of the force of endosmosis; respiration of fishes; action of organic muscle-fibre of the lungs; allotropism of living systems; new facts respecting the action of the skin; functions of nerve-vesicles and their electrical analogues; function of the sympathetic nerve; explanation of the action of certain parts of the auditory apparatus, particularly the cochlea and semicircular canals; new facts respecting the theory of vision and theory of muscular contraction. The special object of the book was, to apply physical theories in the explanation of physiological facts, to the exclusion of the so-called vital principle of the old physicians.

Dr. Draper is a man of a philosophical cast of mind, by which he was drawn to the study of phenomena in their more comprehensive aspects and relations. The wide range of his scientific acquirements, and especially his mastery of physiology, formed an admirable preparation for studying the subjects of human development and the course of civilization from a scientific point of view. His "Physiology" was accordingly soon followed by a work of which the intention was to show that societies of men advance under the government of law. This was entitled "A History of the Intellectual Development of Europe." Few philosophical works have attained so quickly to celebrity. Many editions of it have been published in this country, and it has been translated into almost every European language. The Westminster Review, speaking of it says: "It is one of the not least remarkable achievements in the progress of positive philosophy that have yet been made in the English tongue. A noble and even magnificent attempt to frame an induction from all the recorded phenomena of European, Asiatic, and North African history."

Though in his earlier years Dr. Draper was a skillful mathematical analyst, he has published but few mathematical papers, the most important being an investigation of the electrical conducting power of wires. This was undertaken at the request of Prof. Morse, at the time he was inventing his telegraph. The use made by Morse of this investigation is related by him in Silliman's American Journal of Science and Arts, December, 1843. The paper shows that an electrical current may be transmitted through a wire, no matter what the length may be, and that, generally, the conducting effect of wires may be represented by a logarithmic curve. Among electrical memoirs there is one on the tidal motions exhibited by liquid conductors, and one on the electro-motive power of heat, explaining the construction of some new and improved forms of thermo-electric batteries. An abstract of these improvements is given in the last edition of the "Encyclopædia Britannica" (Art. Voltaic Electricity).

Dr. Draper was the first person to obtain photographs of the diffraction spectrum given by a grating, and to show the singular advantages which that spectrum possesses over the prismatic investigations on radiations. In a memoir on the production of light by chemical action (1848), he gave the spectrum analyses of many different flames, and devised the arrangement of charts of their fixed lines in the manner now universally adopted. A memoir on phosphorescence contains the experimental determination of many important facts in relation to that property. Among purely chemical topics he has furnished a method for the qualitative determination of urea by nitrous acid.

In 1864, at the request of the New York Historical Society, Dr. Draper gave four lectures before that body, which were subsequently published under the title of "Thoughts on the Civil Policy of America." They were respectively on the influence of climate upon man; on the effects of emigration; on the political force of ideas; and on the natural course of national development. They contain discussions of several interesting points, which since that time have largely occupied public 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, a comparison of the European with the American method of government.

No account of Dr. Draper's labor and influence for the promotion of science would be complete that did not mention the admirable series of Introductory Lectures with which he opened his chemical courses in New York from 1840 to 1850. Clear in statement, fresh and striking in their views, and lively, poetic, and witty, as well as instructive, they were well fitted to awaken the enthusiasm of students. Those on "Oxygen," "Atmospheric Air," "Water," and "Phosphorus," were especially brilliant. We have repeatedly tried to induce their author to have them collected and reprinted, but he says they were only fragments designed for a transient purpose, and are not worth preserving in a permanent form. Dr. Draper's manner as a lecturer is quiet and deliberate—too subdued and equal for stirring effect, but perfect for exposition. As a speaker, he has been rarely drawn out of the collegiate sphere, but such efforts as his Introductory Lectures and his felicitous address at the Tyndall banquet show that he has the elements of humor and an art of putting things that would have given him success in the popular field if he had cared to seek it.

From 1860 to 1870 Dr. Draper did but little in scientific research, devoting himself mostly to historical works. During this time he published his "History of the American Civil War," in three volumes. His opportunities for giving accuracy to this work were very great. Mr. Stanton, the Secretary of War, issued orders to the Adjutant-General of the Army of the United States to "furnish him with 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 furnish him with statistical information respecting the armies of the United States, their organization, and operations." This order included all the Confederate archives in possession of the War Department. Nor was the interest of the Secretary of War limited to this: he supplied also a large amount of personal information of the utmost value. Access was not unfrequently given him 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. As was the case with Dr. Draper's other works, this also has been largely republished in Europe.

In the summer of 1870 Dr. Draper suffered a severe bereavement in the loss of his wife. Of Brazilian birth, she was connected with an ancient and noble Portuguese family. She had rendered his domestic life a course of unbroken happiness, and doubtless she was the exemplar before his eyes when he wrote that often-quoted passage in his "Physiology," in which, after depicting the physical and intellectual peculiarities of woman, he says: "But it is in the family and social relations that her beautiful qualities shine forth. At the close of a long life checkered with pleasures and misfortunes, how often does the aged man with emotion confess that, though all the ephemeral acquaintances and attachments of his career have ended in disappointment and alienation, the wife of his youth is still his friend. In a world from which every thing else seems to be passing away, her affection alone is unchanged, true to him in sickness as in health, in adversity as in prosperity, true to the hour of death."

Of their six children, one died in infancy; the survivors are three sons and two daughters. Of the former, the eldest is Professor of Natural History in the College of the City of New York; the second, Professor of Physiology in the University of New York; the third, Director of the Meteorological Observatory in the New York Central Park.

After the death of his wife, Dr. Draper spent the following winter in Europe, chiefly in Rome. Since his return he has published two short memoirs: one, on the "Distribution of Heat in the Spectrum," showing that the predominance of heat in the less refrangible regions is due to the action of the prism, and would not be observed in a normal spectrum, such as is formed by a grating; and that all the rays of light have intrinsically equal heating power. The second is an investigation of the distribution of chemical force in the spectrum. All these scientific researches, to which so many years of his life have been devoted, have been at his own expense; he has never received any extraneous aid, though many of them have been very costly. He has never taken out any patent, but has given the fruits of his investigations and inventions freely to the public.