But before I come to discuss the real source of these bodies it may be well to consider the possibility that meteorites should have been projected from bodies in space which do not belong to the solar system. This is indeed a favourite notion with some, but here again as elsewhere through astronomy the laws of probability afford a reliable guide.
Let us briefly consider the conditions under which a meteorite projected from some volcano located in the stellar spaces would actually pass through the earth's track. No doubt there are scores of millions of stars, and though we cannot see them, there are in all probability thousands of millions of dark globes which, in so far as their non-luminous character is concerned, clearly resemble the earth. It is not improbable that thousands of these globes, or millions of them, may have volcanoes quite as potent, or far more potent than any volcanoes which have ever come within our experience. But even if there were millions of volcanoes or bodies in the stellar space, and even if those volcanoes were powerful enough to discharge missiles which would soar free from their parent globes, the probabilities against the arrival of any such objects on this earth are indeed stupendous. I find it wholly impossible to believe that such can have been the source of meteorites, at all events so long as I can discover another source to which so great a degree of improbability does not attach.
For suppose that a volcano were located on some body lying at the distance of the nearest fixed star, which is believed to be Alpha Centauri. An observer placed in that remote locality and viewing the solar system from the awful distance which intervenes, would see the earth
