312 EXPERIMENTS OF READ AND POUILLET. 



of resemblance besides this one of their obedi- 

 ence to some abstract law." (Isaac Taylor, Sa- 

 turday Evening, p. 131.) 



When men shall thoroughly comprehend the 

 agency of caloric in all the diversified forms of 

 electricity, and how they are resolvable into one 

 general principle, innumerable new truths, the 

 existence of which has not been suspected, will 

 gradually open to view, until the vast and com- 

 plicated machinery of nature shall be fully un- 

 folded, and reduced to an intelligible theory. 



I cannot dismiss this subject without noticing 

 the recent experiments of M. Pouillet, in con- 

 nexion with those of Mr. Read, which were per- 

 formed fifty years ago; because their conclu- 

 sions are in direct opposition to each other. Mr. 

 Read maintained that electricity is given out 

 by aqueous vapour, (the constituents of which 

 are oxygen, hydrogen, and caloric,) and by the 

 vapours that are exhaled from burning sub- 

 stances,* while M. Pouillet contends that elec- 

 tricity is never developed by evaporation, unless 

 attended with chemical action. 



It was before stated, that De Saussure ob- 

 tained electricity during the evaporation of water, 

 from silver and porcelain vessels, where no che- 

 mical action can be supposed to have existed. 



* Mr. Read considered combustion as a species of evaporation, 

 by which solid and fluid bodies were converted more or less 

 rapidly into the gaseous state. 



