Page:Popular Science Monthly Volume 2.djvu/546
THE POPULAR SCIENCE MONTHLY.
add to the fatality. Visitations so severe and disastrous permanently affect the inhabitants of earthquake regions. Their minds lose their calm equipoise — they become nervous, and the first considerable shock sends them to the street or cathedral for safety.
Humboldt remarks that, when "we feel the ground move beneath us, our deceptive faith in the repose of Nature vanishes, and we feel ourselves transferred into a realm of unknown and destructive forces. Every sound, the faintest motion of the air, arrests attention. To man, the earthquake conveys the idea of unlimited danger." And Von Tschudi adds his testimony, that "no familiarity with earthquakes can blunt this feeling of insecurity. The traveller from the north of Europe waits with impatience to feel the movement of the earth, and with his own ear to listen to the subterranean sounds, but, soon as his wish is gratified, he is terror-stricken, and is prompted to seek safety in flight." Thus it is that physical phenomena aid in moulding the mental and moral character of a people. The earthquake records itself, not only on the inorganic world, but in man's spiritual nature.
GALVANI discovered, in 1794, that the muscles of animals experience contractions in contact with certain metals. In his view, this contact merely calls out the discharge of a fluid inherent in the animals themselves. The fact was not to be contested, but its explanation was. Lively discussions in the schools of physiology followed — fortunately, with a clear understanding that the difficulty could only be determined by experiments. A vast number were made, the name of Volta being connected with the most remarkable of them. Alexander Volta maintained, in opposition to Galvani, that the electricity which produces contractions in the muscles, far from originating in those organs, is introduced by the metals used in the process. In proof of this he constructed, in 1800, the pile that bears his name, and which is an arrangement in which the connection of two different metals becomes an abundant source of the electric fluid. Galvani and Volta were two men of distinguished genius, who thoroughly understood physics and physiology, and advanced nothing heedlessly. Their discoveries were the point of departure for one of the most admirable movements in all the history of science, a movement which is still most active, and is the more remarkable because it resulted but yesterday, as it were, in the complete demonstration that Galvani and Volta were both in the right. Science to-day proves that there is an elec-