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 zoédlogical 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 title was changed in 1864 to Professor of Geology and Mineralogy. 
