346 ELECTRld EESONANCE OF MOUNTAINS. 



and gave a very distinct sound ; whether held in a vertical position, with the iron 

 point above or below, ci in a horizontal one, the vibrations remained the same, 

 but no sound escaped from the surface of the ground. 



The sky had become gray over its whole extent, although unequally charged 

 with clouds. Some minutes afterwards I felt the hairs of my head and face 

 stand on end, imparting a sensation analogous to that of a razor passed when dry 

 through a stiff beard. A young Frenchman, who accompanied me, exclaimed 

 that he felt a sensation in every particular hair of his incipient moustache, and that 

 strong currents were issuing from the tips of his ears. On lifting my hand I 

 felt currents quite as distinctly escaping from my fingers. In short, a strong 

 electricity was flowing from staves, clothes, ears, hair, and from all the salient 

 parts of our bodies. 



A single explosion of thunder -rt^as now heard towards the west in the distance. 

 "We quitted the peak of the mountain with some precipitation, and descended 

 about 100 meters. In proportion as we proceed-ed our staves vibrated less and 

 less strongly, and we stopped when their sound had become so feeble as to be 

 no longer perceptible except on bringing them close to the ear. The pain in the 

 back had ceased with the first steps of the descent, but I still retained a certain 

 vague impression of it. 



Ten minutes after the first, a second reverberation of thunder was heard to the 

 west at a great distance, and these were all. No lightning was seen. Half an 

 hour after wo had left the summit the sleet had ceased, the clouds broke awa}', 

 and at 30 minutes after two we again reached the topmost point of the Piz 

 Surley, there to find sunshine. 



We judged that the same phenomenon must have been produced on all the 

 peaks formed by projecting rocks, for all, like that which we occupied, were 

 enveloped in whirls of sleet, while no condensation showed itself in the rest of 

 the sky ; and the great snowy summits of the Bernina, to which clung groups of 

 clouds* seemed also exempt fi'om it. But, the same day, a violent storm l)urst 

 upon the Bernese Alps, where an English lady was struck by lightning. On 

 the horizon, divers peaks, especially the sharpest, such as the Piz Ot and the 

 Piz Languard, continued to be enveloped by sleety whirls, even when the sky 

 had everywhere begun to grow blue. 



I had been the witness of another case of the efflux of electricity from the summit 

 of mountains when I visited, some years ago, the Nevado de Toluca, in Mexico ; 

 but there the phenomenon had still more intensity, as miglit be expected, since 

 it occurred under the tropics, at an altitude of about 4,500 meters. I may be 

 allowed to cite here what I have elsewhere said of it.* 



In the month. of August, 1856, I made, with M, Peyrot, the ascent of the 

 Nevado de Toluca ; it was in the midst of the rainy season, and there was some 

 degree of imprudence in attempting the expedition at that time. We attained 

 the summit without any menacing appearance of the skies, though cumuli were 

 to be seen here and there, and from time to time fogs settled on the needles of 

 rocks which spring aloft from the crest of the mountain. We rested on the 

 border of the crater to recover our strength and enjoy for a moment the grand 

 spectacle which unfolded itself at our feet. Prom the height of the edge the 

 eye plunged into that immense amphitheater, whose focus, long extinct, is now 

 occupied by two small lakes, towards which we were preparing to descend. A 

 cold and disagreeable wind arose from this gulf, and, while we were taking a 

 slight repast, we saw a thick cloud penetrate into the crater by its southeast 

 notch and ascend towards us, eddying around the walls of the amphitheater. 

 Presently we were enveloped in a glacial fog. Surprised by this threatening 

 symptom, we saw that wo had not an instant to lose if we wished to visit the 

 crater, and I commenced clambering down over the rubbish which leads to the 



* Coup (Vmil suT Vhydrologio du Mcxique, 1 part, (note. A) 



