Miscellanies. 401 



Peltier, after due investigation, came to the conclusion that a torna- 

 do is a modification of the thunder gust, in which, in lieu of passing 

 in the form of lightning, electricity passes througl) a cloud, acting as 

 a conductor between the terrestrial surface and the sky. It will be per-' 

 ceived that this view of the subject differs but little from that which, in 

 a memoir in the transactions of the Society, had been presented by 

 Dr. Hare, in the following language : — " A tornado is the effect of an 

 electrified blast of air, superseding the more usual means of discharge 

 between the earth and clouds, in the sparks and flashes which we call 

 lightning. I conceive that the effect of such a current would be to 

 counteract, within its sphere, the pressure of the atmosphere and thus 

 to enable this fluid, in obedience to its elasticity, to rush into the rarer 

 medium above." 



Dr. Hare went on to say, that the only difference arises from the 

 omission of the Parisian philosopher to call in the elasticity of the air 

 in aid of the electrical forces, and his assigning to a cloud the agency 

 which Dr. Hare had attributed to a vertical blast of electrified air, min- 

 gled with every species of movable matter coming within the grasp 

 of the meteor ; and that it would seem, from a subsequent communica- 

 tion made by Peltier to the Institute, that he had so entirely misappre- 

 hended Dr. Hare's theory, as to ascribe to it deficiencies for which it 

 was not amenable, but which had existed in his own explanation, as 

 stated in his report.* 



The fault of Dr. Hare's explanation was, according to him, " en 

 ne tenant pas compte des forces nouvelles que la premiere, (that is 

 to say, the electric attraction,) acquiert par le mouvement gyratoire 

 qui accompagne souvent la coulonne de nuages et d'eau qu'on appelle 

 trombe." 



As the most appropriate refutation of this misstatement, Dr. Hare 

 stated that he would quote a paragraph from his Memoir. 



" Whe7i once a vertical current is establislied, and a vortex pro- 

 duced, I conceive that it may continue after the exciting cause may 

 have ceased. 



" The effect of a vortex in protecting a space about which it is 

 formed, from the pressure of the fluid in which it has been induced, 

 must be familiar to every observer. In fact, Franklin ascribed the 

 water spoilt to a whirlwind. 



* Tout confirme done que latrombe n'est qu'un conducteur nuageux; qu'elle sort 

 de passage aux decharges continuelle de nuages superieure que la difference entre un 

 orage ordinaire et Torage accompagne du trombe, est dans ce conducteur servant k 

 ^tablir le combat entre I'extremite de la trombe, et la portion du sol sitae au dessous. 

 (See Peltier's report upon the tornado of Chatenay, Journal des Debats du 17 Ju- 

 illet, 1839.) 



Vol. xxxvni, No. 2.— Jan .-March, 1840. 51 



