698 THE POPULAR SCIENCE MONTHLY. 



experiments and the extent and variety of the apparatus he em- 

 ployed. He spared no labor or expense in his operations, and, 

 being a handy mechanician, he was able to bestow much ingenuity 

 in the construction of novel devices for experiment and illustra- 

 tion. He accumulated instruments and material with astonishing 

 profusion. To these he added graphic illustrations and lucid de- 

 scriptions to make his lectures intelligible and interesting. When 

 he resigned his professorship, he gave all the apparatus he had 

 accumulated to the Smithsonian Institution. 



He was a man of literary tastes, fond of poetry, and himself 

 wrote verses occasionally. He also sometimes wrote articles on 

 the political and financial questions of the day, and contributed 

 moral essays to the Portfolio, under the signature of " Eldred 

 Grayson." 



In person he had a robust frame, a large head, and an impos- 

 ing figure and presence. 



In his family and among his friends, according to Prof. Silli- 

 man, he was very kind, and his feelings were generous, amiable, 

 and genial ; yet, in the absence of mind occasioned by his habit- 

 ual abstraction, and when absorbed in thought, his manner was 

 occasionally abrupt. With his keen and active mind, conversa- 

 tion would sometimes seem to awaken him from an intellectual 

 reverie. He had great colloquial powers, but to give them full 

 effect it was necessary that they should be aroused by a great and 

 interesting subject, and the effect was heightened by the injection 

 of antagonism. He would then discourse with commanding abil- 

 ity, and his hearers were generally as ready to listen as he to 

 speak. He was a man of unbounded rectitude, a faithful friend, 

 and a lover of his country and its best interests, without thought 

 of personal emolument or political advancement. He was a volu- 

 minous scientific writer. For many years his contributions to 

 the American Journal of Science were more numerous than those 

 of any other correspondent. The full list of them includes about 

 one hundred and fifty articles, in forty-eight volumes of that 

 journal, the record of the titles of which occupies five columns in 

 the General Index of the first fifty volumes. Besides notices of 

 the various substances he discovered or experimented with, and 

 descriptions of apparatus, we find among these articles some 

 that touch the principles of chemical and physical philosophy — 

 as on the nature of acids and salts ; concerning Faraday's views 

 on atoms ; on chemical nomenclature, a subject which is also dis- 

 cussed in a letter to Berzelius ; on some inferences from the phe- 

 nomena of the spark in Thompson's work on heat and electricity ; 

 on the error that electric machines must communicate with the 

 earth ; on a new theory of galvanism ; on the cause of heat : a 

 reply to Prof. D. Olmsted's views on the materiality of heat ; 



