ASA GRAY. 765 



ical laboratory of the jMedical School of New York. His time was 

 here mainly occupied in botanical studies ; and, besides aiding Dr. 

 Torrey in his botanical work, he ])repared and published several original 

 papers of his own, of which his memoir on Rhynchospora may be said 

 to be his first contribution to descriptive botany. His connection with 

 Bartlett's School ended early in 1835, and, although the financial con- 

 dition of the New York Medical School did not permit his continuing 

 as assistant of Dr. Torrey, he returned to New York in the autumn of 

 1835, and accepted the position of curator and librarian of the Lyceum 

 of Natural History, a position which gave him leisure for continuing 

 his botanical studies, and to prepare his first text-book, '' Elements of 

 Botany," which appeared in 1836. 



About this time a Government expedition, since known as the Wilkes 

 Exploring Expedition, was fitting out, and the i>osition of botanist of 

 the expedition was offered to Dr. Gray in the summer of 1836. The 

 expedition did not sail, however, until two years later ; and meanwhile, 

 wearied by the numerous delays and uncertainties about the manage- 

 ment of the expedition. Dr. Gray resigned his position and settled in 

 New York, where, in comj)any with Dr. Torrey, he worked energetically 

 on the preparation of the earlier parts of the " Flora," of which the 

 first two parts appeared in October, 1838. While occupied in this work, 

 a new State University had been founded in Michigan, and Dr. Gray 

 accepted the chair of botany which was offered to him, with the under- 

 standing that he should be allowed to spend a year abroad in study 

 before beginning his official duties. 



The elaboration of the new "Flora" made it necessary for him to 

 examine the types of American plants in foreign herbaria; and in 

 November, 1838, he started on the journey which was not only to give 

 him the means of clearing up much of the existing confusion with re- 

 gard to the identity of previously described North American species, 

 but, what was more important, was to bring him into close scientific 

 and social relations with the botanical lights of a generation now long 

 past, and with those who were then the young men of promise, a brill- 

 iant group, of which Sir J. D. Hooker and A. De Candolle are now 

 almost the only survivors. 



He returned to America in November, 1839, but never assumed the 

 duties of professor at Michigan. He was absorbed in his work on the 

 " F'lora," and refreshed and stimulated by what he had seen and heard 

 abroad, he was pushingrapidly ahead with the second volume, of which 

 he wrote the greatei** portion, and at the same time printing a " Bo- 

 tanical Text-Book," which was to form the basis of his many subse- 

 quent text-books, when he was invited to Cambridge to fill the newly 

 endowed chair of the Fisher Professorship of Natural History in Har- 

 vard College. 



He accepted, and in 1842 took up his residence in Cambridge. The 

 secoTJd volume of the '' Flora " was completed the following year. He 



