Page:In the high heavens.djvu/313

 common bond between objects of such widely different characters is expressed by the fact that they each come into the atmosphere from outside.

If I may say so without offence, it would seem that the logic of the reasoning which connects meteorites with comets is not wholly satisfactory. Some of the arguments which have been brought forward by those who maintain the affinity of meteorites to shooting-star showers appear to be derived from the two following premises. Shooting-star showers come into the air from outside. Meteorites come into the air from outside. But the premises, though both unquestioned, do not admit of our drawing any conclusions as to the affinity of meteorites and shooting-star showers. It is perfectly certain that periodic showers such as the Leonids, or the Perseids, or the Orionids, or the Geminids, or any of the other similar showers, are all cosmical systems possessing distinct affinities to comets. Their origin cannot be discussed separately from the origin of comets. Whence the comets have come, thence these meteors have most probably come, and where that may have been is a question into which I do not now enter. But, besides these bodies, there is another class of objects to which the meteorites belong, which come into our atmosphere, no doubt, but which seem to have no connection with comets. Doubtless there are many of the so-called shooting-stars, or so-called fire-balls, which it would be impossible, with our present knowledge, to assign with certainty to their proper classes. All I am now insisting on is that there are at least two classes of these objects, one of which includes those of cometary affinity, and the other includes the non-cometary objects. It is to the latter that the meteorites belong. This is