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.'"