Page:Popular Science Monthly Volume 4.djvu/378

364 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