AMERICAN GEOLOGY DECADE OF 1840-1849. 



401 



a volume of 580 pages, and a most remarkable work for the time and 

 the conditions/' 



From 1839 to 1842 Professor Dana served as geologist and mineralo- 

 gist on the Wilkes Exploring Expedition, and for the first thirteen 

 years after his return devoted his chief energies to the study of the 

 material collected on the expedition and to the preparation of his 

 reports, of which two — the volume on geology, 756 pages, 5 maps, 

 and 21 plates (1849), and the one on crustaceans, 1,620 pages, with an 

 atlas of 96 plates (1854) — are monumental. His labors, however, were 

 not limited to the reports, for during the same period he prepared and 

 issued three editions of the System of Mineralogy (1844, 1850, 1854) 

 and two editions of the Manual of Geology (1848, 1857), besides writ- 

 ing numerous papers for scientific periodicals. 



Tn 1846 Mr. Dana became an editor of the American Journal of 

 Science, associated with Prof. Benjamin Silliman, who had founded it 

 wenty-eight } T ears before. His labors in 

 connection with the Journal continued until 

 the close of his life. In 1850 he was ap- 

 pointed professor of natural history in Yale 

 College, and in 1864 the title was changed 

 to that of professor of geolog3 T and miner- 

 alogy. His duties as instructor, however, 

 he did not take up until 1855, but after this 

 date, with some interruptions due to ill 

 health, his active connection with the college 

 continued until 1890. It is perhaps well to 

 add that just before his appointment to 

 Yale in 1850 he had been invited to a simi- 

 lar position at Cambridge, Massachusetts, 

 in connection with Harvard College, but by 



the prompt action of a generous friend in the Yale faculty in provid- 

 ing the necessary funds he was induced to remain in New Haven and 

 accept the "Silliman Professorship.' 1 



In 1859 long-continued overwork brought a breakdown of serious cnaracter and 

 from which he never fully recovered, and although later some degree of health came 

 back, he was always subject to the severest limitations until the end of his life. Only 

 those immediately associated with him could appreciate the inexorable character of 

 these limitations and the self-denial that was involved, not only in restricting work 

 and mental effort, but also in avoiding intercourse with other men of science and 

 friends in general, in which he always found the greatest pleasure. Little by little 



«The "System" has now gone through six editions, though after 1868 the work 

 was done mainly and finally wholly by his son, Prof. E. S. Dana, now professor of 

 Physics and Curator of the Mineralogical Collection in the same university. The 

 last edition, that of 1892, comprises 1,104 royal octavo pages with over 1,400 figures 

 in the text. 



1^1 



Fig. 41.— James Dwight Dana. 



NAT MUS 1904- 



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