3 66 THE POPULAR SCIENCE MONTHLY. 



tages which that spectrum possesses over the prismatic investigations 

 on radiations. In a memoir on the production of light by chemical 

 action (1848), he gave the spectrum analyses of many different flames, 

 and devised the arrangement of charts of their fixed lines in the man- 

 ner now universally adopted. A memoir on phosphorescence contains 

 the experimental determination of many important facts in relation to 

 that property. Among purely chemical topics he has furnished a 

 method for the qualitative determination of urea by nitrous acid. 



In 1864, at the request of the New York Historical Society, Dr. 

 Draper gave four lectures before that body, which were subsequently 

 published under the title of " Thoughts on the Civil Policy of America." 

 They were respectively on the influence of climate upon man ; on the 

 effects of emigration ; on the political force of ideas ; and on the natu- 

 ral course of national development. They contain discussions of sev- 

 eral interesting points, which since that time have largely occupied 

 public attention, such as the internal emigration from the Atlantic 

 States to the West, the Asiatic emigration to the Pacific States, the 

 political effects of polygamy in Utah, the tendency of democratic in- 

 stitutions to centralization, a comparison of the European with the 

 American method of government. 



No account of Dr. Draper's labor and influence for the promotion 

 of science would be complete that did not mention the admirable series 

 of Introductory Lectures with which he opened his chemical courses 

 in New York from 1840 to 1850. Clear in statement, fresh and strik- 

 ing in their views, and lively, poetic, and witty, as well as instructive, 

 they were well fitted to awaken the enthusiasm of students. Those on 

 " Oxygen," " Atmospheric Air," " Water," and " Phosphorus," were es- 

 pecially brilliant. We have repeatedly tried to induce their author to 

 have them collected and reprinted, but he says they were only frag- 

 ments designed for a transient purpose, and are not worth preserving in 

 a permanent form. Dr. Draper's manner as a lecturer is quiet and de- 

 liberate — too subdued and equal for stirring effect, but perfect for ex- 

 position. As a speaker, he has been rarely drawn out of the collegiate 

 sphere, but such efforts as his Introductory Lectures and his felicitous 

 address at the Tyndall banquet show that he has the elements of 

 humor and an art of putting things that would have given him suc- 

 cess in the popular field if he had cared to seek it. 



From 1860 to 1870 Dr. Draper did but little in scientific research, 

 devoting himself mostly to historical works. During this time he pub- 

 lished his " History of the American Civil War," in three volumes. His 

 opportunities for giving accuracy to this work were very great. Mr. 

 Stanton, the Secretary of War, issued orders to the Adjutant-General 

 of the Army of the United States to " furnish him with copies of all 

 orders, reports, correspondence, telegraphic dispatches, or other docu- 

 ments on file in the War Department, as he might request, and to per- 

 mit him to inspect and have copies of any maps, plans, and other pa- 



