produced on Mountains by Electricity. 125 



the rainy season, and it was almost imprudent to attempt the 

 expedition at that time. We reached the summit without the 

 sky appearing threatening, although we saw some cumuli float- 

 ing about, and fogs for a moment skimmed close over the spires 

 which crown the mountain. We seated ourselves at the edge of 

 the crater to recover our strength and enjoy the grand view 

 which was spread below us. From the top of the slope we 

 looked down into that vast amphitheatre whose hearth, long cold, 

 is now filled by two little lakes, towards which we made ready to 

 descend. A cold and disagreeable wind blew up from the gulf; 

 and while we took our scanty meal we saw a thick cloud pene- 

 trate to the crater by its south-eastern opening and mount 

 towards us, creeping up the walls of the amphitheatre. We 

 were soon enveloped in an ice-cold fog. Surprised by that 

 threatening symptom, we saw that we had not a moment to lose 

 if we were to visit the crater ; and I began to descend across the 

 rubbish which conducts to the depth of the amphitheatre. But 

 scarcely had I reached halfway, when the storm, breaking out 

 with astonishing suddenness, obliged me to remount as soon as 

 possible to my point of departure. It was at first fine rain, then 

 a little very fine hail driven by violent wind. In an instant the 

 mountain was whitened, and the cold became intense. The 

 thunder, which was atflrst intermittent,now rolled almost uninter- 

 ruptedly and with frightful violence, above all when it arose from 

 the amphitheatre of the crater, where I saw the flash of the light- 

 ning often fall. Without any shelter, in the midst of naked rocks, 

 without even a block to cower under, our only resource was to 

 sit down on the ground, turning our backs to the hail. After a 

 short time the cold became insupportable, and, with fear of the 

 tempest, drove us from the summit, though we had not finished 

 our observations. 



While we were hastily descending the rocks forming the 

 summit of the Nevado, rain for an instant succeeded the 

 sleet. As we were threading a little stony ravine formed by 

 ancient runs of trachyte, and where vegetation begins, the 

 storm appeared to grow calm for an instant, the claps of thun- 

 der ceased, or grew distant, and we saw a dark cloud approach ; 

 it passed over us, enveloping us, and was accompanied with frozen 

 sleet. Soon we saw the hairs of our Indians move as though 

 about to stand up, and we felt various electrical sensations at 

 the beard and at the ears. Next we heard a deep indefinable 

 sound, at first weak though general, but soon stronger and very 

 distinct. It was a universal rattling, as though all the small stones 

 on the mountain were being shaken together. The terrified 

 Indians in their conversation gavefree course to their superstition; 

 and it is true that the clamour which then reigned in the moun- 



