126 NATIONAL ACADEMY OF SCIENCES 



years, Professor Dana resided for a part of the time in Washing- 

 ton, but after his marriage to the daughter of Professor Silliman, 

 he made his home in New Haven, that city then offering better 

 facilities for his work. Besides the report on geology, which 

 formed a large quarto volume with 21 plates, he also wrote the 

 reports on zoophytes and crustaceans consisting of three quarto 

 volumes, with atlases of more than 150 plates. Most of the 

 drawings were made with his own hand. 



On February 18, 1856, Dana delivered his inaugural address 

 as " Silliman Professor of Natural History " at Yale, to which 

 position he had been appointed in 1850.' During the 40 years 

 that followed, he spent the greater part of the time not occupied 

 by his duties as professor, in writing new general works on 

 mineralogy and geology or preparing new editions of earlier 

 ones, and in zoological and geological investigations. The titles 

 of his communications to scientific societies and journals during 

 this period number more than 100. The first edition of his 

 " Manual of Geology" appeared in 1862, and in 1864 the first 

 edition of his " Textbook of Geology." In 1868, the fifth edition 

 of his " System of Mineralogy " was published; " a monumental 

 work, the most complete treatise, indeed, that had ever been 

 attempted." 



In 1870, Dana began the study of the glaciers of New 

 England and published a monograph on the geology of the 

 New Haven region. Two years later his book on " Corals and 

 Coral Islands " was published, and he began the study of the so- 

 called " Taconic " rocks of New England. In 1875 he published 

 a book called " The Geological Story Briefly Told." After some 

 years in which ill health interfered seriously with his activities, 

 in 1887 he visited the Hawaiian Islands, where he studied the 

 volcanoes. He prepared at this time a work on volcanoes which 

 was published in 1890, and another called "The Four Rocks 

 of the New Haven Region " which appeared the following year. 

 In 1892 he retired from his active duties as a professor in the 



"The tide was changed in 1864 to Professor of Geology and Mineralogy. 



