348 BIOGRAPHICAL SKETCHES. 



pedia Britannica," — the best treatise of the kind of its day in 

 the English language, and one of the most influential. In 

 conjunction with his early friend, Sir William Hooker, he 

 wrote the " Contributions to the Flora of South America," 

 etc., which form a long series of articles in the " Botanical 

 Miscellany," "Journal of Botany," and other similar periodi- 

 cal or serial publications edited by Sir William. He took a 

 similar part in the k ' Botany of Beechey's Voyage " ; in con- 

 nection with Dr. Wight he brought out the first volume of the 

 " Prodromus Florae Peninsula? India? Orientalis " ; and made 

 numerous contributions to various periodicals. Up to 1845 

 or somewhat later Dr. Arnott was one of the foremost bota- 

 nists of the time, one of the most zealous and sagacious, versed 

 alike in European and exotic botany. But upon assuming the 

 duties of his chair at Glasgow he appears soon to have aban- 

 doned the field in which he had won the highest honors, and 

 in which much more was justly expected. He assumed, how- 

 ever, the joint authorship of Hooker's " British Flora," tak- 

 ing, we believe, the whole charge and responsibility of the later 

 editions. As he began with Mosses, so for the last fifteen or 

 twenty years of his life he devoted himself principally to the 

 Diatomacece, bringing to their investigation all the ardor of 

 his nature and the keenest powers of observation, combined 

 with indomitable patience and unwearied care. So that he 

 became in this department of microscopical research one of 

 the highest authorities, and amassed one of the richest collec- 

 tions extant. As a professor he was greatly esteemed and 

 respected, although he may be thought to have come almost 

 too late in life to the professor's chair. In his later years he 

 was much withdrawn from general botanical intercourse ; but 

 his surviving correspondents and friends on this side of the 

 ocean cherish very pleasant memories of him. 



