HIS INTELLECTUAL QUALITIES. 319 



sense. To a vigorous understanding he united a 

 power of. application which made him through life 

 a most industrious man. These qualities, together 

 with his rhetorical talents, and the winning features 

 of character and manner that belonged to him, well 

 fitted him for his peculiar work. That work was to 

 collect and diffuse scientific truth. His vocation was 

 that of a teacher. Through the period of his active 

 service he was awake to the progress of discovery. 

 In a letter addressed to Professor A. M. Fisher, be 

 fore the news of the loss of the Albion had reached this 

 country, and which came back to the writer ftorr 

 London, he says : "I will thank you, when you 

 visit the lecture-rooms and scientific establishments 

 in London, Paris, and Edinburgh, to notice wifh 

 reference to me, whatever is new and interesting, 

 and to make a memorandum of it at the time. An 

 insulated lecturer is in danger of growing rusty and 

 falling short of the progress of improvement. Should 

 you see any new piece of chemical apparatus, which 

 comes within the means in your hands, I wish you 

 would secure it." In this spirit he managed his 

 department of instruction. Nor is he without merit 

 as an investigator, although his distinction does not 

 lie here. He was never very careful to claim for 

 himself the credit of scientific discovery. At the 

 same time, he took delight in doing honor to the 

 discoveries of others. His first edition of " Henry's 

 Chemistry," appeared in 1808, with the modest an 

 nouncement, " to which are added notes by a 

 Professor of Chemistry in this country." As soon 

 as Gay Lussac's method of obtaining potassium by 

 the decomposition of its hydrate by heat in an iron 



