356 PIONEERS OF SCIENCE IN AMERICA. 



fell into my hands when I was about sixteen years old, and was 

 the first work I ever read with attention. It opened to me a 

 new world of thought and enjoyment ; invested things before 

 almost unnoticed with the highest interest ; fixed my mind on 

 the study of Nature, and caused me to resolve at the time of 

 reading it that I would immediately commence to devote my 

 life to the acquisition of knowledge." In accordance with that 

 resolve he resigned from the dramatic society and betook 

 himself to study. At first he attended a night school and 

 after a time entered Albany Academy, paying his way by teach- 

 ing a country district school and later serving as assistant in 

 the academy. On leaving this institution he obtained the posi- 

 tion of tutor in the family of the patroon, General Stephen Van 

 Rensselaer, of Albany, occupying his leisure hours in studies 

 preparatory to the medical profession, to which he added the 

 higher mathematics. General Van Rensselaer was an old 

 friend of the family. He regarded Henry in the light of a 

 son, and Henry was wont to say that the general taught him 

 what it was to have a father, and what were the feelings of a 

 son. Later he made a survey for a road across the southern 

 part of the State, from West Point to Lake Erie. In 1826 he 

 returned to the Albany Academy as an assistant, and in 1828 

 was made Professor of Mathematics. 



Mr. Henry had now become interested in the subject of 

 electro-magnetism, which had recently been much advanced by 

 the discoveries of Oersted and Ampere. In 1827 he read before 

 the Albany Institute a paper entitled On Some Modifications 

 of the Electro-magnetic Apparatus. "By his skilful experi- 

 mental investigations," says Mr. William B. Taylor, in speaking 

 of this paper, " Henry was enabled to exhibit all the class illus- 

 trations, attempted by Sturgeon, not only on a still larger and 

 more conspicuous scale, with the use of feeble magnets (where 

 required), but with a still further reduction of the battery 

 power ... by the simple expedient of adopting, in every case 

 where single circuits had hitherto been employed, the manifold 

 coil of fine wire which Schweigger had employed to increase 

 the sensibility of the galvanometer." This was Henry's first 

 contribution to electrical science. "Should any one be dis- 

 posed to conclude that this simple extension of Schweigger's 

 multiple coil was unimportant and unmeritorious, the ready an- 

 swer occurs that talented and skilful electricians labouring to 



