1838] WRITINGS OF JOSEPH HENRY. 105 



THE LATERAL DISCHARGE OF ELECTRICITY. 



(Proceedings of the American Philosophical Society, vol. i, p. 6.)* 



February 16, 1838. 



Professor Henry made a verbal communication on the 

 lateral discharge of electricity while passing along a wire, 

 as in the Leyden experiment, or communicated directly to 

 an insulated wire, or to a wire connected with the earth, and 

 detailed various experiments proving that free electricity is 

 not, under any circumstances, conducted silently to the 

 earth. 



INDUCTION CURRENTS FROM ORDINARY ELECTRICITY. 



(Proceedings of the American Philosophical Society, vol. i, p. 14.) 



May 4, 1838. 



Dr. Patterson read a letter from Professor Henry, of Prince- 

 ton, dated May 4, 1838, announcing that in recent experi- 

 ments he has produced directly from ordinary electricity 

 currents by induction analogous to those obtained from gal- 

 vanism, and that he has ascertained that these currents pos- 

 sess some peculiar properties ; that they may be increased 

 in intensity to an indefinite degree, so that if a discharge 

 from a Leyden jar be sent through a good conductor a 

 shock may be obtained from a contiguous but perfectly in- 

 sulated conductor more intense than one directl}"^ from the 

 jar. Professor Henry remarks that he has also found that 

 all conducting substances screen the inductive action, and 

 that he has succeeded in referring this screening process to 

 currents induced for a moment in the interposed body. 



* [The title-page of vol. i (comprising the proceedings from Jan., 1838, 

 to Dec, 1840,) hears date 1840.] 



