402 EEPORT OF NATIONAL MUSEUM, 1904. 



the power for work was restored and by husbanding his strength so much was accom- 

 plished that, besides other writing, he was able to bring out in 1862 the first edition 

 of his Manual of Geology, and in 1864 the Text-book of Geology, and four years later 

 his last and most important contribution to mineralogy, the fifth edition of the 

 "System." This last great labor, extending over four years, was followed by a 

 turn of ill health of an alarming character and from which restoration was again 

 very slow. 



The years that immediately followed were rilled with the same quiet labor, geo- 

 logical investigations in the field, the writing of original papers and books, the 

 editorial work of the Journal, and his duties as a college instructor. 



They were remarkably productive years, notwithstanding- the diffi- 

 culties contended against, notably bis renewed illness in 1874 and 1880. 

 A large number of important papers were published, chietry in the 

 Journal. New editions of the Manual of Geology were issued in 

 1874, 1880, and 1895; of the Text-book in 1874 and 1883; while a new 

 geological volume called The Geological Story Briefly Told was issued 

 in 1875, and one on the Characteristics of Volcanoes in 1890, after his 

 second visit to the island. A second edition of his book on Corals and 

 Coral Islands, the first edition of which appeared in 1872, was also 

 brought out in 1890. 



But it was not as an investigator and writer only that Dana achieved 

 success. As a teacher he seems to have won the respect and regard 

 of all with whom he came in contact, and to have left on the minds of 

 students — even those who had no taste for geology — a lasting and 

 favorable impression. Many of his sayings in class lectures were 

 epigraphic: "1 think it better to doubt until you know. Too many 

 people assert and then let others doubt." Again, "1 have found it 

 best to be alwa^^s afloat in regard to opinions on geology. " 



Nor can we regard him as merely a geologist. His work on crus- 

 taceans, comprising 1,620 pages, with an atlas of 96 plates (1854), 

 shows that equal success could have been attained in the biological 

 Held had he chosen to follow it. The mental vigor and staying powers 

 of the man were simply extraordinary, and it is not too much to say 

 that he stands out head and shoulders above all his contemporaries, if 

 not above all who preceded him. His interest nev T er flagged; no 

 problem was too large for him to grasp, no detail too small for his 

 consideration. 



It would seem quite extraordinary that two men who have done so 

 much for American geology, whose work was really epoch making, 

 who, without doubt, excelled any geologists of their time in ability to 

 h. d. and w. b. unravel the difficult structural problems of any region, 

 Richmond Bowlder should have been so extremely visionary in theoretical 

 Train, 1848. matters. The peculiar ideas of H. D. Rogers on the 



subject of the elevation of the Appalachians are elsewhere referred to. 

 I wish here to notice their equally extraordinary ideas regarding the 



