Page:Popular Science Monthly Volume 34.djvu/857

Rh 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."