ZIGZAG MOTION OF THE ELECTRIC 5£ARK. <f><2§ 



■air is a transformation of the aqueous vapour which constantly 

 ascends in the atmosphere. — 3 That rain is produced by the 

 decomposition of that air, which returns to aqueous vapour, 

 first in thuds, from which, by their condensation, rain pro- 

 ceeds. 



Those among natural philosophers who have not adopted Different hy- 

 this system, being however obliged to explain the production ^ ?^* q "jL 

 of rain, have supposed that the aqueous vapour, ascending in ent with facts, 

 the atmosphere, accumulates in its upper parts, where it is 

 condensed by the cold of that region. But in the first place 

 it has been found by Mr. de Saussure, and myself, by hy- 

 groscopical observations, that the more we ascend in the at- 

 mosphere, the less of aqzieous vapour is mixed with the air. 

 Besides, from this hypothesis, rain should fall only in the 

 night, when the atmosphere cools after sunset. But the 

 spring of this year has furnished a test to the atmospheric 

 systems. We have had almost incessant rains, with great 

 storms. Where could that enormous quantity of water be 

 contained, if not in the composition of the air itself ? — What 

 could have occasioned these tremendous local storms, ex- 

 cept the decomposition of air in certain extents, toward which 

 the other air was rushing? 



However this analysis of the constitution of the atmosphere Another ob- 

 is not necessary to show how groundless the author's hypo- auThor's^po! 

 thesis is; for it is a known fact, that if such distinct gasses thesis. 

 as oxigen and hidrogen exist in its mass, they are no where 

 separated in the whole of its extent, from the plain to the top 

 of the highest mountains : consequently the electric spark can 

 no where be attracted on one side more than another, even 

 were it proved that these fluids possess different conducting 

 faculties. Therefore there remains only the explanation 

 which the author rejects, because he was not informed of 

 these facts. 



There is a phenomenon, which shows to the sight the Falling stars, 

 manner in which some fluids, distinct from atmospheric air, 

 ascending in the atmosphere, follow their course; I mean 

 what is called falling stars, when they follow a long track. 

 This is a phosphoric fluid, ascending from some spot of the 

 surface of the Earth. It is invisible in its ascent, because 

 there is some circumstance required to make it phosphores- 

 cent, 



