Popular Science Monthly/Volume 34/April 1889/Sketch of James Pollard Espy
|SKETCH OF JAMES POLLARD ESPY.|
METEOROLOGY is one of the youngest of the sciences. Most of what is settled and systematized has been developed within the memory of men who are still living. The contributions of Americans to research in this branch have been among the most important. Among the earlier labors in this field none deserve or have received wider recognition than those of Prof. Espy. He may, indeed, be regarded with justice as the founder of the science as at present cultivated in relation to storm predictions.
James P. Espywas born in Westmoreland County, Pa., May 9, 1785, and died in Cincinnati, Ohio, January 24, 1860. While he was still an infant his father moved to the Blue Grass region of Kentucky; but, on finding the institution of slavery antagonistic to the principles inherited from his Huguenot ancestry, he removed after a few years to the Miami Valley in Ohio. One of his daughters had in the mean time married a Kentuckian of Mount Sterling, and James, remaining with this sister for the sake of the opportunity, became, at eighteen years of age, a student in Transylvania University, at Lexington. Here he was visited in 1805 by an elder brother, who was engaged in the practice of the law in Pennsylvania, who wrote of him: "I met my brother James, whom I had not seen since he was an infant. I found him at the university, where he had made considerable progress in the dead languages and in general science. He shows an ardent desire for knowledge, and promises to be both intelligent and useful." He was graduated in 1808, and went to Xenia, Ohio, where he taught school and studied law. Of this part of his career, Mrs. L. M. Morehead, his niece, in her "Few Incidents" of his life, says that "his love for teaching amounted to enthusiasm, and, although he completed his law studies, he finally abandoned the idea of choosing the law as his profession, and determined to follow the bent of his inclination, and become a conscientious instructor of youth." To his latest years "he considered this a noble profession, and even in old age was fond of drawing out young students to talk over their lessons with him, both hearing them and asking them questions." Either before or after this—the authorities differ—he filled creditably and satisfactorily the position of principal of the academy at Cumberland, Md., where he married Miss Margaret Pollard, who afterward gave him her full sympathy and encouragement in his meteorological researches.
In 1817 Mr. Espy became a teacher in the classical department of the Franklin Institute, a position in which, according to the late Prof. A. D. Bache, he became known as "one of the best classical and mathematical instructors in Philadelphia, which at that day numbered Dr. Wylie, Mr. Sanderson, and Mr. Crawford among its teachers. Impressed by the researches and writings of Dalton and of Daniell on meteorology," Prof. Bache continued, in a eulogy before the Regents of the Smithsonian Institution, "Mr. Espy began to observe the phenomena and then to experiment on the facts which form the groundwork of the science. As he observed, experimented, and studied, his enthusiasm grew, and his desire to devote himself exclusively to the increase and diffusion of the science finally became so strong that he determined to give up his school, and to rely for the means of prosecuting his researches upon his slender savings and the success of his lectures, probably the most original which have ever been delivered on this subject. His first course was delivered before the Franklin Institute of Pennsylvania, of which he had long been an active member, and where he met kindred spirits, ready to discuss the principles or the applications of science, and prepared to extend their views over the whole horizon of physical and mechanical research. As chairman of the Committee on Meteorology, Mr. Espy had a large share in the organization of the complete system of meteorological observations carried on by the Institute under the auspices and within the limits of the State of Pennsylvania." Mrs. Morehead quotes from the account of a friend who visited him in Philadelphia a description of Prof. Espy's method of pursuing his atmospheric calculations, which necessarily had to be carried on out of doors. The high fence inclosing the small yard was of smooth plank, painted white, while the space inclosed was filled with vessels of water and numerous thermometers for determining the dew-point. The white fence, when last seen by the narrator, was so covered with figures and calculations that not a spot remained for another sum or column. Prof. Espy's theory of storms was first developed in successive memoirs in the "Journal of the Franklin Institute," containing discussions of the changes of temperature, pressure, and moisture of the air, and of the direction and force of the wind, and other phenomena attending remarkable storms in the United States and on the ocean adjacent to the Atlantic and Gulf coast. "Assuming great simplicity," says Prof. Bache, "as it was developed, and founded on the established laws of physics, and upon ingenious and well directed experiments, this theory drew general attention to itself, especially in the United States. A memoir submitted anonymously to the American Philosophical Society of Philadelphia gained for Mr. Espy the award of the Magellanic premium in the year 1836, after a discussion remarkable for ingenuity and closeness in its progress, and for the almost perfect unanimity of its result."
In 1840 Prof. Espy, by invitation, visited England for the purpose of explaining his theory of storms before the British Association. He presented it, in an elaborate paper, in September, 1840, Prof. Forbes being the presiding officer of the meeting, after which it was subjected to a lively discussion, in which some of the most eminent British scientific men of the day took part, some sustaining it, and some presenting objections to it. He afterward visited Paris, and presented a communication to the Academy of Sciences. The committee to whom the communication was referred, consisting of MM. Arago, Pouillet, and Babinet, at the conclusion of their report, admitted that the memoir "contains a great number of well-observed and well-described facts. His theory in the present state of science alone accounts for the phenomena, and when completed, as Mr. Espy intends, by the study of the action of electricity when it intervenes, will leave nothing to be desired. In a word, for physical geography, agriculture, navigation, and meteorology, it gives us new explanations, indications useful for ulterior researches, and redresses many accredited errors. The committee expresses, then, the wish that Mr. Espy may be placed by the Government of the United States in a position to continue his important investigations, and to complete his theory, already so remarkable, by means of all the observations and all the experiments which the deductions even of his theory may suggest to him in a vast country, where enlightened men are not wanting to science, and which is, besides, the home of those fearful storms. The work of Mr. Espy causes us to feel the necessity of undertaking a retrospective examination of the numerous documents already collected in Europe, to arrange them, and draw from them deductions which they can furnish, and more especially at the present period, when the diluvial rains which have ravaged the southeast of France have directed attention to all the possible causes of similar phenomena. Consequently, the committee proposes to the Academy to give its approbation to the labors of Mr. Espy, and to solicit him to continue his researches, and especially to try to ascertain the influence which electricity exerts in these great phenomena, of which a complete theory will be one of the most precious acquisitions of modern science."
This report was incorporated in full in the introduction to "The Philosophy of Storms"—"not merely," as the author says with characteristic independence of opinion, "for the purpose of showing the reader that I have the highest authority on my side—for I do not submit to authority myself—but to exhibit a beautiful analysis of my theory by three of the most distinguished philosophers in Europe. As a matter of authority, however, I should be justified in bringing forward the report to rebut authority. It had been sneeringly said before a large audience, by a distinguished professor, that I had failed to convince men. of science of the truth of my theory, and that I had appealed to the people, who are incapable of judging. It became, therefore, necessary to obtain authority against authority."
The origin of the studies upon which the theory of storms is based is traced in the opening paragraph of the "Philosophy" to the result described by Dalton, that the quantity of vapor in weight, existing at any time in a given place, could be determined by means of a thermometer and a tumbler of water cold enough to condense on its outside a portion of the vapor in the air. "It occurred to me at once," Prof. Espy says, "that this was the lever with which the meteorologist was to move the world. I immediately commenced the study and examination of atmospheric phenomena, determined to discover, if possible, what connection there is between rain and the quantity of vapor in the atmosphere." Prof. Espy prefaced his paper in the British Association by saying that he had found, by examining simultaneous observations in the middle of storms and all round their borders, that the wind blows inward on all sides of a storm toward its central parts; toward a point if the storm is round, and toward a line if the storm is oblong, extending through its longest diameter. The theory is, in brief, that every atmospheric disturbance begins with the ascension of air that has been rarefied by heat. The rising mass dilates, and, as its temperature falls, precipitates vapor in the form of clouds. Owing to the liberation of the latent heat, the dilatation continues with the rising till the moisture of the air forming the upward current is practically exhausted. The heavier air flows in beneath, and, finding a diminished pressure above it, rushes upward with constantly increasing violence. The great quantity of aqueous vapor precipitated during this atmospheric disturbance gives rise to heavy rains. Much of this theory still holds good; but it has been found that the motion of the wind in storms is rotary.
Besides his explanation and proofs of this theory. Prof. Espy presented to the British Association a paper on "Four Fluctuations of the Barometer." The theory was more fully elaborated in "The Philosophy of Storms," which was published in a large octavo volume by Little, Brown & Co., Boston, in 1841, and was re-enforced by detailed descriptions of a large number of storms occurring on the land and the ocean, the course of which the author had been able to follow and study with considerable accuracy. It also contained his answers to the disturbances in the equilibrium of temperature, whence follow ascending currents, cloud and rain. He spent much effort in trying to secure an experimental demonstration of this scheme, and made unsuccessful petitions to Congress and the Legislature of Pennsylvania for appropriations to enable him to carry them out on an adequate scale. The scheme was not regarded as practicable, and he became the object of some ridicule for his enthusiasm—to which he replied in his book with the self-possession of a man who believes to the full in his purposes: "Gentlemen have made their puns on this project, and had their laugh: and I am sorry to see, by letters which I have received, that my friends and relations at a distance are much troubled by these innocent laughs; but let them be consoled: I have laughed too, well knowing that those who laughed the most heartily would be most willing to encourage the experiment as soon as they discovered they had nothing to laugh at. As a proof that I was right in this anticipation, I may be permitted to say that I have lately received a letter from a highly distinguished member of the American Legislature, who laughed as heartily as any one when my petition was presented them, containing many kind expressions, and promising me, by way of amends for his levity, to avail himself of the earliest opportunity of being better informed on the subject of my new philosophy. Such conduct as this is all I want; I fear not the strictest scrutiny." The same confident spirit is exhibited in his letter to his superior in the War Department, suggesting a second year of employment in the official study of storms, and which is given in fac-simile on the following page.which had been made against his theory in the British Association and elsewhere by prominent men of science and rival meteorologists. In it, furthermore, he defended his theory that storms could be produced by large fires making local
In 1843 Prof. Espy was given a position in the War Department, where he could pursue his investigations in atmospheric currents and disturbances, and receive reports from distant points of observation. He instituted a service of daily weather reports, out of which our present Signal-Service system has grown; and, on the basis of this enterprise, as Mrs. Morehead relates in her book. Prof. Henry once remarked to her that there was no question in his mind that "Prof. Espy should be regarded as the father of the present Signal Service of the United States, his ' Theory of Storms ' having led the way to its establishment and present success." Prof. Henry added that the charts now used in the service were identical (with some modifications ) with those that the "Old Storm King" constructed for use in the Meteorological Bureau of the War Department when he was at its head. A similar acknowledgment was made by General Myer. Prof. Espy was for several years a regent of the Smithsonian Institution, and was brought into close relations and friendship with Prof. Henry. On the occasion of his death, Prof.
Bache pronounced his eulogy in the Board of Regents, and the Regents passed memorial resolutions, one of which describes him as "one of the most useful and zealous of the meteorologists cooperating with the Institution, whose labors in both the increase and diffusion of knowledge of meteorology have merited the highest honors of science at home, and have added to the reputation of our country abroad."
Prof. Espy delivered many lectures in the towns, cities, and villages of the United States, explaining his theories and the results of his observations. These efforts were very successful, and, according to Prof. Bache, by their originality attracted more attention to his views than could have been obtained in any other way. "He soon showed remarkable power in explaining his ideas. His simplicity and clearness enabled his hearers to follow him without too great effort, and the earnestness with which he expressed his convictions carried them away in favor of his theory." He was also remarkably successful in gaining the sympathy of public men, and, through them, in obtaining from the Government continued opportunities for study, research, and the comparison of observations. His reports to the Surgeon-General of the Army, to Congress, and to the Secretary of the Navy, are mentioned as among his latest efforts in this direction.
Prof. Espy is charged with the one scientific defect that, with his deep conviction of the truth of his theory, and the enthusiasm it fed in him, he could not pass beyond a certain point in its development, and for the same reasons his deductions were often unsafe. He was not prone to examine and re-examine premises and conclusions, but considered what had once been passed upon by his judgment as finally settled. "Hence his views did not make that impression upon cooler temperaments among men of science to which they were entitled, obtaining more credit among scholars and men of general reading in our country than among scientific men, and making but little progress abroad." But, toward the close of his life, he was induced, by the Secretary of the Smithsonian Institution, to re-examine the various parts of his theories, and to insert in his "Fourth Report," while it was going through the press, an account of his most mature views.
Prof. Espy thought much on subjects of mental and moral philosophy, and after his death his relatives in Cincinnati published his short "Treatise on the Will," which is described as embodying some original and striking ideas.
Personally, according to Prof. Bache, "Prof. Espy was eminently social, full of bonhomie and enthusiasm, easily kindling into a glow by social mental action. In the meetings and free discussions of a club formed for promoting research, and especially for scrutinizing the labors of its members, and of which Sears C. Walker, Prof. Henry, Henry D. Rogers, and myself were members, Mr, Espy found the mental stimulus that he needed, and the criticism which he courted, the best aids and checks to his observations, speculations, and experiments. But there was one person who had more influence upon him than all others besides, stimulating him to progress, and urging him forward in each step with a zeal which never flagged—this was his wife." Mrs. Morehead says that "he never seemed impatient or concerned at the slow recognition of his discoveries as means of practical use in commerce or other national needs. He would say, 'I leave all this to the future, sure that its adaptation to the uses of life must one day be seen and acknowledged.'"
- "A Few Incidents in the Life of Professor James P. Espy, by his Niece, Mrs. L. M. Morehead," Cincinnati, Robert Clarke & Co.
- Hon. J. J. Crittenden.