SKETCH OF DR. J. W. DRAPER. 365 



of the coagulation of the blood ; theory of the circulation of the 

 blood ; explanation of the flow of sap in plants ; endosmosis of gases 

 through thin films; measure of the force of endosmosis; respiration 

 of fishes ; action of organic muscle-fibre of the lungs ; allotropism 

 of living systems ; new facts respecting the action of the skin ; func- 

 tions of nerve-vesicles and their electrical analogues ; function of the 

 sympathetic nerve ; explanation of the action of certain parts of the 

 auditory apparatus, particularly the cochlea and semicircular canals ; 

 new facts respecting the theory of vision and theory of muscular con- 

 traction. The special object of the book was, to apply physical theo- 

 ries in the explanation of physiological facts, to the exclusion of the 

 so-called vital principle of the old physicians. 



Dr. Draper is a man of a philosophical cast of mind, by which he 

 was drawn to the study of phenomena in their more comprehensive 

 aspects and relations. The wide range of his scientific acquirements, 

 and especially his mastery of physiology, formed an admirable prepara- 

 tion for studying the subjects of human development and the course 

 of civilization from a scientific point of view. His " Physiology " was 

 accordingly soon followed by a work of which the intention was to show 

 that societies of men advance under the government of law. This was 

 entitled " A History of the Intellectual Development of Europe." Few 

 philosophical works have attained so quickly to celebrity. Many edi- 

 tions of it have been published in this country, and it has been trans- 

 lated into almost every European language. The Westminster Re- 

 view, speaking of it says: "It is one of the not least remarkable 

 achievements in the progress of positive philosophy that have yet 

 been made in the English tongue. A noble and even magnificent at- 

 tempt to frame an induction from all the recorded phenomena of 

 European, Asiatic, and North African history." 



Though in his earlier years Dr. Draper was a skillful mathematical 

 analyst, he has published but few mathematical papers, the most im- 

 portant being an investigation of the electrical conducting power of 

 wires. This was undertaken at the request of Prof. Morse, at the time 

 he was inventing his telegraph. The use made by Morse of this inves- 

 tigation is related by him in Sillimari > s American Journal of Science 

 and Arts, December, 1843. The paper shows that an electrical current 

 may be transmitted through a wire, no matter what the length may be, 

 and that, generally, the conducting effect of wires may be represented 

 by a logarithmic curve. Among electrical memoirs there is one on 

 the tidal motions exhibited by liquid conductors, and one on the elec- 

 tro-motive power of heat, explaining the construction of some new and 

 improved forms of thermo-electric batteries. An abstract of these im- 

 provements is given in the last edition of the " Encyclopaedia Britan- 

 nic a " (Art. Voltaic Electricity). 



Dr. Draper was the first person to obtain photographs of the dif- 

 fraction spectrum given by a grating, and to show the singular advan- 



