METEOROLOGY AND AEROLITES.
Who has not seen a shooting star? For a moment the bright objects dart through greater or less spaces in the heavens, and then disappear. Those of inferior size give but little light, and are seldom seen unless the eye is, at the time, directed toward the space they traverse. Occasionally one flames out with such brilliancy as to light up, for a moment, the whole heavens. These are called meteors—a name quite proper for both classes, and only the very ignorant suppose any of them to be real stars. They come singly, two or three in an hour, or in showers, such as were witnessed in 1833. When of such size that they strike the earth before being consumed by their intense heat, they are aerolites, or meteoric stones. Great masses of these are found in different places, and show such a peculiar combination of their chemical elements as to distinguish them from all other stones; and mineralogists generally conclude they were not formed on the earth. Whence they come is not certainly known. That they were formed by an aggregation of their materials in our atmosphere seems incredible. Nor were they thrown off by some great convulsion, from the moon, with force sufficient to carry them beyond the attraction of that body. Perhaps most astronomers now believe, on what they think sufficient evidence, that the celestial spaces are occupied by innumerable small bodies moving round the sun, of whose nature and orbits nothing is certainly known. The earth, it is supposed, while making its annual circuit, must be constantly encountering them, and, as in passing rapidly through the upper region of the atmosphere they take fire and burn, the shooting star or meteor is simply the light of that flame. The mechanical production of heat, now well understood, shows why they burn. The rapid motion of the earth, especially if it be duplicated by that of the minute body striking through its atmosphere, would generate heat sufficient to quite consume the meteoroids; so that generally their solid substance is dissipated before they reach the ground. Sometimes the heated aerolite explodes when in such proximity to the earth that the fragments fall before they are consumed.