138 The Smithsonian Institution 



without any special or immediate reference to its application 

 to the wants of life or useful purposes in the arts.' He 

 sought no patents for inventions, and solicited no remunera- 

 tion for his labors, other than credit for having done what it 

 was in him to do for the promotion of scientific knowledge. 

 He gave freely to the world the results of his researches, and 

 others devoted themselves to the practical applications of the 

 principles which he discovered. Of these were not only 

 Morse in America, but Wheatstone and Cooke in this coun- 

 try. It has been amply demonstrated that these inventors 

 were at a standstill in the early part of 1837 for the want of a 

 means of producing a strong effect at the receiving station. 

 Although Henry had clearly shown the advantage of employ- 

 ing closely wound coils of fine wire in 1831, Wheatstone 

 knew nothing apparently of this, and remained in ignorance 

 until April, 1837, when he was enlightened by Professor 

 Henry himself. We are firmly convinced that Henry did 

 more for the advancement of the telegraph than has ever yet 

 been adequately acknowledged." l 



Another practical outgrowth of his early investigations in 

 connection with which his name has less frequently been 

 mentioned, because perhaps there has been less controversy 

 in regard to its history, was the production of mechanical 

 power by electro-magnetism. 



Henry in 1829 constructed the first electro-magnetic motor, 

 an oscillating machine with automatic pole-changer. This he 

 described in i83i. 2 In 1833 Sturgeon constructed the first 

 rotary motor, which he exhibited to the learned men in Lon- 

 don, giving to Henry credit for priority in construction of 

 electro-magnetic engines. 



The English electrician Joule writes : 



" It is to the ingenious American philosopher that we are 

 indebted for the first form of the working model of an engine 



1 Electrical Review, London, August 12, 1887, Volume xxi, page 162. 

 2 American Journal of Science, 1831, Volume xx, page 340. 



