]24 M. H. de Saussure on the Humming Sound 



I understood at once that my sensations were from a strong 

 flow of electricity taking place from the summit of the mountain. 

 Some improvised experiments produced no spark from our sticks, 

 nor light perceptible by day ; they vibrated strongly in the hand, 

 and gave out a very pronounced sound ; whether held vertically, 

 the point upwards or downwards, or, on the other hand, ho- 

 rizontally, the vibrations remained identical, but no sound escaped 

 from the soil. The sky had become grey over its whole extent, 

 though unequally charged with clouds. Some minutes after- 

 wards I felt my hair and beard stand out, causing me to feel a sen- 

 sation like that resulting from a razor passed dry over the bristles. 

 A young Frenchman who was with me cried out that he felt the 

 hair of his moustache growing, and that strong currents were 

 flowing from the tips of his ears. liaising my hand, I felt cur- 

 rents no less strong flow off from the fingers. Briefly, strong 

 currents of electricity flowed from our staves, clothes, from our 

 ears, hair, and all salient parts of our bodies. A single thunder- 

 clap was heard in the distance to the westward. We left the 

 summit in some haste and descended about a hundred metres. 

 The further we advanced the less strongly our sticks vibrated, 

 and we stopped when the sound had become too weak to be per- 

 ceived except on bringing them close to the ear. The pain in the 

 back ceased from the first step in our descent, but I still retained a 

 vague feeling of it. Ten minutes after the first a second thunder- 

 clap was heard again to the westward and very distant ; and these 

 were the only ones. No flash was seen. Half an hour after 

 leaving the summit the sleet had ceased, the clouds broke, and 

 in two hours and a half we reached anew the summit of the Piz 

 Surley to find there the sun. We judged that the same pheno- 

 menon must have been produced on all the spires formed by 

 needle-pointed rocks ; for all, like that we were on, were sur- 

 rounded by vortices of sleet : in the rest of the sky no con- 

 densation was produced, and the great snowy tops of the Bernina, 

 to which were attached masses of cloud, appeared also free from 

 the sleet. But the same day a violent storm broke out in the Ber- 

 nese Alps, where an Englishwoman was killed. On the horizon 

 divers peaks, especially the sharp ones, were surrounded by hail- 

 showers, even when the sky began to grow clear in all directions. 



I was witness to another case of flowing of electricity from the 

 summits of mountains when I visited, some years ago, the Nevado 

 de Toluca in Mexico ; but there the phenomenon had more in- 

 tensity, as one may well understand, as it took place within the 

 tropics, at a height of about 4500 metres. Permit me here to 

 repeat what I have elsewhere related. 



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

 ascent of the Nevado de Toluca. We were in the height of 



