OF ARTS AND SCIENCES. 293 



by the tornado cloud as figured in Peltier's work, '' Sur la 

 Formation des Trombes," which he considered as utterly 

 irreconcilable with that theory. He objected to the electrical 

 theories of tornadoes as unsatisfactory, inasmuch as they refer 

 the elevating force to the attraction between the cloud and 

 subjacent bodies on the earth's surface. " The cloud with its 

 cone is not a fixed, coherent mass, but is composed of free, 

 disconnected, and mutually repellent parts, which are situated 

 at unequal distances from the earth, and are therefore une- 

 qually attracted by its oppositely electrified surface ; so that 

 the only obstacle to the descent of the lower parts, in obedience 

 to the electrical attractions, is their inferior specific gravity, 

 compared with that of the underlying air. Any attraction, 

 therefore, exerted by the cloud, sufficient to raise into the air 

 men, wagons, and other heavy bodies, must necessarily, it 

 should seem, cause the lowest and most strongly attracted 

 portions of the cloud to rush with immense velocity to the 

 earth, to be followed by others in their turn ; a phenomenon 

 which has never been observed." 



The principal elevating agency of electricity in tornadoes 

 had, he thought, been entirely overlooked by those who had 

 written on the subject. This agency consisted, as he con- 

 ceived, in augmenting the mutual repulsion of the particles of 

 air and water composing the cloud, and thereby expanding it, 

 and diminishing its specific gravity to an indefinite extent. 

 " Hence must result great elevating force. The contiguous 

 portions of the underlying air being acted upon by powerful 

 attraction from above, and superior pressure from beneath, must 

 rush up into the cloud with great velocity, and be followed by 

 other portions in their turn. As this effect accumulates and is 

 greatest in the cone where the electrical repulsion and conse- 

 quent rarefaction are the greatest, the ascending currents of 

 air must constitute a force capable of raising very heavy bod- 

 ies. The cold that will result from this great expansion may 

 account for the hail that usually accompanies the tornado." 



Professor Lovering observed, that the vast disproportion be- 



