and of indicating by most striking apparatus the methods of solving many intricate problems. The qualities that Jamin displayed in his oral teaching are found in his "Traité Général de Physique," which reproduces his course at the Polytechnic School, and "in which masters as well as pupils find exact descriptions of the actual state of science." This work was published 1858 to 1861, in three volumes.
M. Jamin was elected to the Section of Physics in the Academy of Sciences in 1868. In 1884 he was chosen perpetual secretary in the place of Dumas. His address on the anniversary of the admission of M. Dumas to the Academy was regarded as a rare example of pathetic eloquence; and in 1885 he delivered an address on the occasion of the centenary of M. Arago, which was characterized by its philosophical examination of the labors of that distinguished experimenter, and its thoughtful analysis of his mental powers, as well as by the clearness with which these points were presented.
M. Jamin's labors were carried on in very diverse branches of physics; and he interested himself and became versed in other departments of science and art. While studying for the degree in Physics at the Normal School, he also qualified himself for a degree in Natural Sciences. At Caen he took geological and botanical excursions with his pupils on Sundays. Of his regular studies he was first occupied with optics. His first memoir, already spoken of, on the reflection of light from metallic surfaces, was in this line, and was one of the best studies of the kind. Others were his studies of interferences, and of the measurement of the indices of refraction, of gases, of water under different pressures, and of the vapor of water. He discovered the elliptical polarization of light reflected by vitreous substances near the polarizing angle, and the negative elliptical polarization of fluorine; he published a memoir on colored rings, and invented interference apparatus in which the light reflected on opposed faces of thick transparent rings was utilized. He made discoveries in capillarity. In 1873 he exhibited a foliated magnet which was capable of carrying twenty-two times its own weight, while the greatest carrying power attained by artificial magnets previous to that time had been from four to five times their weight. This result was obtained by substituting, for the thick plate hitherto employed, a sufficient number of very thin plates superposed on each other, and all thoroughly magnetized. In these and other experiments in electrical science M. Jamin was greatly assisted by the research laboratory which M. Duruy had endowed. Among the later fruits of these researches was the perfection of the Jamin electric light, as an improvement upon the Jablochkoff candle. In his description of this lamp, the inventor sums up its qualities by saying: "It lights and relights itself as often as is required; it only requires one circuit for all the neighboring candles; it replaces automatically those which are entirely consumed, by new carbons; it employs no insulating material which might alter the color of the
