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Page:Popular Science Monthly Volume 54.djvu/533

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THE GREAT BOMBARDMENT.

various angles producing a variety of forms known as Widmanstatten figures which a few years ago formed the basis of a singular sensation. The figures were supposed to be fossil shells and various animals of a diminutive size which once populated the wrecked world of which the meteor was assumed to be a part. These meteoric animals from space were named and classified by several observers, who were finally forced to acknowledge that their creations were the fanciful markings of crystallization.

Another class of meteorites (meteoric iron stones) may be described as spongy masses of nickeliferous iron in whose pores are found grains of chryosite and other silicates. A type of these bodies is the meteor of Pallas, which was discovered by him in 1772. The third class of meteoric stones are those in which the stony or silicous predominates. As a rule they contain scattered metallic grains, but certain ones, as the aƫrolite which fell at Gara, France, in 1806, contain metallic constituents.

The aƫrolites present an attractive appearance when made into sections, showing crystals and splinterlike fragments, and under the glass seem to be made up of many minute spheres ranging from those the size of a cherry down to others invisible to the naked eye. The minerals prominent in their composition are chrysolite, bronzite, augite, enstatite, feldspar, chronite, etc., showing a marked similarity to the eruptive rocks so well known on the earth. The collections of famous meteorites in the various museums of the world have constantly been examined and studied with a view to determine their origin, the question being a fascinating one to layman and scientist. Astronomers in the past have variously answered the question. The flying fragments were believed by some to be the wreckage of other worlds. Planets had perhaps collided and been rent asunder in former ages, and space filled with the flying fragments. Others thought that meteors were molten matter thrown from the earth or moon. All these theories have been relinquished in view of evidence of a more or less convincing character pointing to the conclusion that the bombardment of the earth is one of the results of the disintegration of comets. In other words, cometary matter flying not always blindly through space, but in the orbit of the comet of which it originally formed a part, constituting the missiles.

It is known that the meteors were formed in a region where air and water were absent. It is equally evident that life was not a factor in the past history of the bodies, though it must be acknowledged that the hydrocarbons resembling terrestrial bitumens which are found in some meteorites suggest the possibility of vegetable life. These comets, the mysterious bodies which seem to be roving through space, misconceived planets, as it were, forced into the world half