Electrical Countries, and their Action on the Weather. 135 



versal crepitation, as if all the little stones on the mountain 

 were jostled together. After a lapse of five or six minutes, 

 thunder came on again, and rain, which lasted to the borders 

 of the forest region, when the storm became more endurable, 

 partly from the greater distance of the focus of electrical dis- 

 turbance • and also from partial discharges which were promoted 

 by the vegetation. 



Previous to this, M. Oraveri, a Mexican physician, had 

 been present at a similar spectacle, on the 19th of May, 1845, 

 when it was suddenly induced by a cloud coming from the 

 north-west. The guides and himself experienced electrical 

 sensations at all their extremities — their fingers, noses, and 

 ears, followed by a dull sound, though no thunder was heard. 

 The long hair of the Indians became stiff and erect, giving 

 their heads an appearance of enormous size, and thus aggra- 

 vating their superstitious terrors. The noise at length grew 

 more intense. It appeared to extend throughout the moun- 

 tain, and was like the rattling of flints, alternately attracted 

 and repulsed by electricity ; but was probably due to the 

 tapping sound of innumerable sparks starting from the rocky 

 soil. In this case no hoar-frost came on. 



The same observer experienced another storm on the 15th 

 of September, 1855, near the summit of Popocatepetl, which 

 differed from the preceding one only that, taking place on the 

 snow-fields, there was no crepitation of stones. 



These Mexican storms, which remind me of less striking 

 results observed in the Alps, have been noticed in May, Au- 

 gust, and September — that is to say, in the most stormy 

 period for Europe; and the coincidence ought not to be 

 neglected. It will also be remarked that the storm of the 19th 

 of May, 1845, was brought on by a west wind. 



Phenomena of another kind have been observed at Chi- 

 huahua, in the Mexican Confederation, but more north. New 

 York has supplied Professor Loomis with an assemblage of 

 facts not less curious, in connection with the presence of an 

 excessive quantity of electricity in the atmosphere. In the 

 winter, hair frequently becomes electrical, especially when a 

 fine comb is used. The greater the efforts made to smooth 

 the hair, the rougher it becomes. It moves towards the fingers 

 that approach it, and the only way to remedy this inconve- 

 nience is to make it damp. 



At the same seasons woollen clothes, especially trowsers, 

 attract particles of down or floating dust. These particles 

 collect chiefly towards the feet, and brushing makes them 

 stick tighter ; a damp sponge is the only mode of removing 

 them. During the night, thick carpets in hot rooms crackle 

 and shine when walked over. By passing over them two or 



