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- 
eal or serial publications edited by Sir William. He took a 
similar part in the “ Botany of Beechey’s Voyage” ; in con- 
nection with Dr. Wight he brought out the first volume of the 
“ Prodromus Flore Peninsulz Indize 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 
Diatomacee, 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was much withdrawn from general botanical intercourse ; but 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. 
