306 LAVOISIER AND LAPLACE. 



converted into vapour by the agency of solar 

 heat, it acquired a greater capacity for electricity, 

 which it absorbed and carried into the atmos- 

 phere during the process of evaporation ; that it 

 was liberated whenever the vapour was con- 

 densed by cold, and thus accumulated in the 

 upper regions of the air ;* that when clouds are 

 formed, which are good conductors of electricity, 

 they become a medium by which electricity is 

 conveyed back to the earth in a tranquil manner, 

 or in the form of lightning, according as it is 

 more or less abundant. (Journal de Physique, 

 Aoiit. 1783.) 



The experiments of Lavoisier and Laplace, 

 published in the Memoirs of the French Academy 

 in 1781, were intended to prove that electricity 

 is disengaged during the process of evaporation : 

 but their results were vitiated by the agency of 



* Seneca informs us that Anaxagoras taught that lightning 

 descended from the setherial regions, and was collected in clouds, 

 from which it was discharged after being greatly accumulated. 

 The same hypothesis has been recently brought forward as new 

 by Dr. Hare, with this difference, that he supposes the earth to 

 constitute another great reservoir of the electric fluid, and that 

 the atmosphere is situated between two oceans of electricity; 

 while the clouds formed in the non-conducting air, operate as. 

 moveable insulated conductors. He further supposes, that thunder 

 storms are more frequent during warm than cold weather, in 

 consequence of the greater elevation to which the clouds then 

 attain, and their consequent approximation to the celestial ocean 

 of electricity. (Theoretical suggestions respecting the causes of 

 the tornado, or water-spout, &c. by Robert Hare, M.D. of Phi- 

 ladelphia.) 



