316 POUILLET, DE SAUSSURE, AND HARRIS. 



were exhibited as in the experiments with burn- 

 ing hydrogen. (An. de Chim. et de Phys.XXXV. 

 401, et XXX VI. 5.) 



The principal error of M. Pouillet, was in 

 supposing that electricity is never produced by 

 evaporation, unless attended with more or less 

 chemical action that when water was evapo- 

 rated from platinum cups, no electricity was 

 evolved. In addition to the evidence of De 

 Saussure, are the recent experiments of Mr. 

 Harris, who has found that the evaporation of 

 pure water from platinum vessels is attended 

 with a distinct evolution of electricity so that 

 the doctrine of Pouillet cannot be admitted, that 

 atmospheric electricity is wholly supplied by 

 chemical action and the growth of vegetation. It 

 is impossible to conceive that the vast amount 

 of lightning disengaged from aqueous vapour, 

 could be generated by chemical action, which is 

 far more energetic upon the dry land than in the 

 ocean, from which the vapour is obtained : nor 

 can it be maintained that the process by which 

 water is separated from the ocean brine is che- 

 mical ; for I have shown, that it is a mechanical 

 force, which is proportional to temperature. (See 

 Chap. iii. Book 1. and the subsequent examina- 

 tion of the two electric fluids.) 



From the brief history thus presented of at- 

 mospheric electricity, it must be obvious to the 

 ^intelligent reader, that the knowledge hitherto 

 derived from experimental researches, has been 



