364 THE POPULAR SCIENCE MONTHLY. 



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 tempera- 

 ture 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 jour- 

 nals. 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. Kirchhoif 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 Lon- 

 don and Edinburgh Philosophical Magazine, July, 1860, the same facts 

 under the guise of mathematical deductions, with so meagre a refer- 

 ence to what Draper had done that he secured the entire credit of 

 these discoveries. In an historical sketch of spectrum analysis subse- 

 quently published, Kirchhoff avoided all mention of his American pred- 

 ecessor. 



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 re- 

 garded 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 col- 

 lege, 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 for- 

 eign 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 



