Hew Outlmes of Chemical Philosophy. 271 



known that lightning is an electrical phaenomenon, and that, 

 •electricity is the cause of many others ; but how electricity should 

 produce the ordinary winds, rain, hail, snow, clouds, vapours of 

 all kinds, hurricanes, whirlwinds, waterspouts, and all the va- 

 rious changes of our atmosphere itself, with regard to its specific 

 gravity, rarefaction, heat and moisture, as indicated by the ba- 

 rometer, thermometer, and hygrometer, is a philosophical ques- 

 tion that cannot be solved, till the laws which obtain between 

 matter and the elements of electricity be more fully investi- 

 gated. 



The electric spark is seldom seen in nature, except in a thun- 

 der-storm, or in the silent summer lightning. But those two 

 elements which produce the spark, produce various other phae- 

 nomena, that are daily taking place in our atmosphere. Nor 

 does their influence stop h^re ; for they are the springs that keep 

 in motion the living principle of both animals and vegetables, 

 and cause them to perform all their various functions. And a». 

 neither animal nor vegetable life can be brought into existence 

 ■without heatj it follows, that even the living principle itself de- 

 pends, in some measure, upon those elements wiiich produce all 

 electrical phaenomena. Although these effects are not produced 

 by the electric spark, yet they are the effects of the same causes, 

 whose operations are rendered more mild, and less perceptible, 

 by acting at a greater distance. 



When an excited surface is brought near an insulated con- 

 ductor, a spark passes between them ; this is called communi- 

 cated electricity: but wiien an excited surface is placed at a 

 greater distance from the conductor, so as not to produce a 

 •park, the effect is called electricity by position or induction. 



The distinction that has been made between these two effect* 

 is, that communicated electricity is permanent, but inducted 

 electricity ceases on removing the excited surface. But this 

 hypothesis of inducted electricity is erroneous, although it ha« 

 been adopted by Professor Robison, and other writers on elec- 

 tricity. The learned Professor recommends "several brass con- 

 ductors, each supjjorted on an insulated stalk lind foot. They 

 should be about an inch and a half, or two inches long, and 

 about three-fourths of an inch in diameter, with rounded ends, 

 and well polished to prevent all dissipation." — Ency. Brit. Sup. 

 vol. i. p. 571. 



But in a conductor of these dimensions, the two elements can 

 be separated oidy to a short distance, and, consequently, will re- 

 unite tlie instant that the excited surface is removed. Hence 

 it seems highly probable, tiiat the Professor's erroneous conclu- 

 iiion arose from the imperfection of his instruments. 



Indeed, 



