140 Additional Objections to Redjield''s Theory of Storms. 



93. In November last, subsequently to the submission of the 

 opinions above expressed to the Academy, I verified a conjecture 

 of my friend Dr. J. K. Mitchell, that moist, foggy or cloudy air 

 is not a conductor of electricity, its influence, in paralyzing the 

 efficacy of electrical apparatus, arising from moisture deposited 

 on adjoining solid surfaces. 



94. A red hot iron cylinder, upon which evidently, no moisture 

 could be deposited, suspended from the excited conductor of an 

 electrical machine, was found to yield sparks within a receiver 

 replete with aqueous vapor, arising from a capsule of boiling 



' water. 



95. Hence it appears that bodies of air, whether cloudy or 

 clear, may be oppositely electrified, from each other or from the 

 earth. This would explain the gyration on a horizontal axis 

 which seems to be attendant on thunder gusts, and may account 

 for the ascent of the southeaster and descent of the northwester 

 in the great storm of Dec. 1836, described by Prof. Loomis. 



96. Such gyration may be a form of convective discharge, in 

 which electrical reaction is assisted by calorific circulation and 

 the evolution of latent heat, agreeably to Dalton and Espy. 



97. Squalls may be the consequence of electrical reaction be- 

 tween the terrestrial surface and oppositely excited masses of air, 

 and the intermixture of masses so excited, in obedience to the 

 same cause, may be among the sources of rain, hail, and gusts. 

 The specific gravity of a body of air, electrified differently from 

 the surrounding medium, may be lessened by what is called elec- 

 tric repulsion; the particles inevitably moving a greater distance 

 from each other, as similarly electrified pith balls are known to do. 



98. Hence a cause of rarefaction, buoyancy, and consequent 

 upward motion, in a column of electrified air, more competent 

 than that suggested by Espy. 



99. Should it be verified that a gyration from right to left takes 

 place, during convective discharges of electricity in hurricanes, it 

 may be referrible to the disposition which a positive electrical 

 discharge from the earth to the sky would have to gyrate in that 

 direction. 



