Earthquake Under the Tropics. -- The impression which the first earthquake makes upon us, even if it is unaccompanied by subterranean noise, is an inexpressibly powerful and quite peculiar one. What moves us so powerfully is, the disappointment of our inherent faith in the repose and immutability of the firm solid earth. A moment destroys the illusions of a life. We are undeceived as to the repose of the earth, and feel transported within the sphere of destroying unknown powers. We scarcely trust the ground on which we stand; the strangeness of the occurrence produces the same anxious uneasiness in animals. Pigs and dogs especially are overpowered by it; the crocodiles of the Orinoco, generally as dumb as our little lizards, leave the agitated bed of the river, and rush howling into the forests. To man, an earthquake appears as something omni-present, unbounded. We can escape from an active eruption, or from a lava-stream flowing towards our dwelling; but during an earthquake wherever one flies seems the hearth of destruction.--Lives of the Brothers Humboldt.