Similar striking indications of the prevalence of electric action have frequently been observed by travelers when near the summits of high mountains, as by Sir W. J. Hooker on Ben Nevis, Saussure on Mont Blanc, and Tupper on Mount Etna. The latter, descending a field of snow, a good conductor, felt a slight shock upon entering a cloud which seemed electric, with a sensation of pain in the back. The hair of his head stood erect, and upon moving the hand near the head, a humming sound proceeded from it, which arose from a succession of sparks. Though a situation of great danger, yet we have several instances of such clouds having been traversed with impunity, when in the act of electrical explosion. The Abbé Richard, in August 1778, passed through a thunder-cloud on the small mountain called Boyer, between Chalons and Tournus. Before he entered the cloud, the thunder sounded, as it is wont to do, with a prolonged reverberation; but when enveloped in it, only single peals were heard, with intervals of silence, without any roll; and after he had passed above the cloud, it reverberated as before, and the lightning flashed. The sister of M. Arago was a party to a similar occurrence between Estagel and Limoux, and some officers of engineers likewise, during a trigonometrical survey on the Pyrenees. The energy of atmospheric electricity appears to decrease as we recede from the equator to the poles, thus sympathizing with light and heat; for it is in tropical countries that the most terrific flashes of lightning and the loudest bursts of heaven’s artillery occur. Awful as these manifestations are occasionally in our temperate climate, they are but as a skirmishing of outposts to the general engagement of armies, when compared with inter-tropical displays. In Hindustan, in the Indian Ocean, along the African coast off Cape St. Verde, and in Central America, there is often a scene exhibited, which seems a rehearsal of the day “when the heavens being on fire shall pass away with a great noise.” Humboldt, during his residence at Cumana, witnessed a coincident development of electrical action, peculiar atmospheric phenomena, and terrestrial disturbance, during what is called the winter of that region. From the 10th of October to the 3d of November, a reddish vapor rose in the evening, and in a few minutes covered the sky. The hygrometer gave no indication of humidity; the diurnal heat was from 82·4° to 89·6°. The vapor disappeared occasionally in the middle of the night, when brilliantly white clouds formed in the zenith, extending toward the horizon. They were sometimes so transparent that they did not conceal stars even of the fourth magnitude, and the lunar spots were clearly distinguishable through the veil. The clouds were arranged in masses at equal distances, and seemed to be at a prodigious elevation. From the 28th of October to the 3d of November, the fog was thicker than it had been before; and the heat at night was stifling, though the