14 Atmospherical Electricity. 



This, certainly, must be regarded as a considerable at- 

 mospheric commotion, whether we regard the material de- 

 vastation it produced, or the influence which the displace- 

 ment of the air, and the mass of hail deposited on the sur- 

 face of two long and broad bands of country, must have ex- 

 ercised on the normal temperature of a great number of 

 places. Could meteorologists, however skilled, have been able 

 to foresee it? 



The origin of the two bands was in the district of Aunis, 

 and in Saintonge. Why there, and not elsewhere ? Why 

 did not the storm commence at another point of the parallel 

 of latitude, passing by its meridional extremities % Because, 

 it will be answered, in Aunis and in Saintonge, on the 13th 

 July 1788, the conditions of electricity and temperature were 

 eminently favourable for the production of a hail-storm, and 

 an accompanying hurricane directed from the south-south- 

 west to the north-north-east. Admitted ; but were not these 

 thermal and electrical conditions favourable to the produc- 

 tion of a storm, ultimately connected with agricultural oper- 

 ations, with the existence of such and such a mass of trees, 

 with the state of irrigation, with circumstances varying ac- 

 cording to the wants and caprice of men ? With regard to 

 temperature, no one can hesitate in his reply. In the other 

 particular, the connection will appear not less evident if I 

 bring to mind that evaporation is a fertile source of electrici- 

 ty, and that various natural philosophers have even included 

 vegetation among the causes which generate this same fluid 

 in the atmosphere. 



If it be true, as has been alleged, that, in certain cases, the 

 flame and smoke which issue from the mouth of a furnace, 

 or from the chimney of a manufactory, may deprive the atmo- 

 sphere of all electricity for many leagues around, the prophets 

 in meteorology, will be placed in an additional difficulty. It 

 will be necessary that they should know beforehand all the 

 plans of the masters of forges and proprietors of manu- 

 factories. 



According to all that we most certainly know respecting 

 the physical cause of water-spouts, and according to M. 



