78 Notices of Tornadoes, (^*c. 



From the report of Peltier, of which I subjoin a translation, it 

 will be seen that, excepting his neglect of the co-operative influ- 

 ence of the elasticity of the air, he sanctions my opinion that a 

 tornado is the effect of an electrical discharge,* 



"Yesterday," says Peltier, "I visited the commune of Chate- 

 nay in the canton of Ecouen, department of Seine and Oise, and 

 investigated the disasters experienced in the month of June last, 

 from a tornado which first originated over the valley of Fontenay 

 des 'Louvres. At present I can give only a summary account of 

 this wonderful phenomenon. 



" Early in the morning a thunder cloud arose to the south of 

 Chatenay, and moved at about ten o'clock over the valley between 

 the hills of Chatenay and those of Ecouen. The cloud having ex- 

 tended itself over the valley, appeared stationary and about to pass 

 away to the . west. Some thunder was heard but nothing remarka- 

 ble was noticed, when about midday a second thunder storm com- 

 ing also from the south and moving with rapidity advanced towards 

 the same plain of Chatenay. Having arrived at the extremity of the 

 plain above Fontenay, opposite to the first mentioned thunder 

 cloud, which occupied a higher part of the atmosphere, it stopped 

 at a little distance, leaving spectators for some moments uncertain 

 as to the direction which it would ultimately take. That two 

 thunder clouds should thus keep each other at a distance, led to 

 the impression that being charged with the same electricity, they 

 were rendered reciprocally repellent, and that a conflict would ensue 

 in which the terrestrial surface would play an important part. Up 

 to this time there had been thunder continually rumbling within 

 the second thunder cloud, when suddenly an under portion of this 

 cloud descending and entering into communication with the earth, 

 the thunder ceased. A prodigious attractive power was exerted 



* I had presented copies of the pamphlet containing my memoir to M. Arago and 

 several other membei's of the Institute. In a subsequent conversation he referred 

 to some of the suggestions which it contained. As itconve)'ed a view of the ques- 

 tion decisively favorable to the claimants, it may be inferred that it must have 

 been alluded to by Arago and thus have become the source of Peltier's impressions. 

 It may therefore be anticipated that due acknowledgment will be hereafter made 

 by him when he realizes his promise of making a more elaborate report on the tor- 

 nado of Chatenay. Before entering upon the arguments by which I sustained my 

 hypothesis it was briefly stated in the following words : " After maturely considering 

 all the facts I am led to suggest that a tornado is the effect of an electrified current of 

 air s^iperscding the more tisual means of discharge between the earth and clouds, in 

 those vivid sparks which we call lightning.'^ 



