288 JOSEPH HENRY, LL.D. 



conductor, would neither produce sparks nor shocks 

 would, if the wire were sufficiently long, produce 

 both those phenomena. . . . 



" A series of investigations was afterwards made, 

 resulting in producing inductive currents of differ- 

 ent orders, having different directions, made up of 

 waves alternately in opposite directions. . . . 



''Another series of investigations, of a parallel 

 character, was made in regard to ordinary or fric- 

 tional electricity. In the course of these it was 

 shown that electro-dynamic inductive action of 

 ordinary electricity was of a peculiar character, 

 and that effects could be produced by it at a re- 

 markable distance. For example, if a shock were 

 sent through a wire on the outside of a building, 

 electrical effects could be exhibited in a parallel 

 wire within the building.". . . 



After this, investigations were made in atmos- 

 pheric induction ; induction from thunder clouds ; 

 in regard to lightning rods ; on substances capable 

 of exhibiting phosphorescence, such as the diamond, 

 which, when exposed to the direct rays of the sun, 

 and then removed to a dark place, emits a pale blue 

 light ; on a method of determining the velocity of 

 projectiles ; on the heat of the spots on the sun as 

 compared with the rest of his disk ; the detection 

 of heat by the thermal telescope "when the 

 object was a horse in a distant field, the radiant 

 heat from the animal was distinctly perceptible at 

 a distance of at least several hundred yards ; " 

 on the cohesion of liquids ; on the tenacity of soap- 



