Physics 523 



been a great revival of interest in Henry's work, and the 

 appearance of these volumes was most timely. 



Most physicists are well informed concerning his discov- 

 eries in electricity and magnetism especially, but the interests 

 of the general reader demand at least brief reference to them 

 in this place. 



The work of an able, successful man is so mixed up with 

 his personality that it is often difficult to properly describe 

 the former without some reference to the latter. Of Henry 

 the man this is not the appropriate place to speak at 

 length, but his relation to contemporary discovery cannot be 

 fully understood without remembering that his leading per- 

 sonal characteristics were modesty, great patience, untiring 

 industry, and an attention to the minutest detail which is 

 rarely found among men of his class in intellectual power. 

 He was conscientious, almost to excess, in the performance 

 of any duty that came to him. He was educated in the 

 Albany Academy, in which, almost immediately after gradua- 

 tion, he was employed as a teacher. By one of his pupils 

 of that time he is referred to as one " who rose with the sun 

 to instruct his pupil, eager after knowledge," and as " giving 

 his heart and soul to the duties of the school." Notwith- 

 standing the fact that his duties demanded nearly his entire 

 time during the daylight hours, he found leisure to begin and 

 carry on a series of investigations that were destined to 

 render both him and the otherwise little-known Academy 

 famous for all time. His first important work was the de- 

 velopment and perfecting of the electro-magnet. With this 

 now commonplace but most important electrical device three 

 names will always be associated. Shortly after the announce- 

 ment of Oersted's brilliant discovery, which furnished the 

 first connecting link between electricity and magnetism, Arago 

 had announced the interesting fact that if rods of steel or 



