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seen. Probably it was missed, not because of its complete disintegration, but because it happened to pass its perihelion at a time when the earth was too far away to admit of the comet being visible. But, what is still more curious is that the meteors themselves, a shower of which was expected in 1899-1900, did not reappear in great numbers at either date. The probable reason for this is that the swarm was deflected from its course by the attraction of the planets, which continually changes the orbit of every object of this kind.

The general conclusion is that the countless thousands of comets which in time past have coursed around the sun, leave behind minute fragments of their mass, which follow in their orbits like stragglers from an army, and that, when the earth encounters a swarm of these fragments a meteoric shower is produced. But it is still an open question whether all these meteoric particles can be fragments of comets, with the probabilities in favor of a negative answer. If we are to accept the conclusions drawn by Professor Elkin from recent photographs of meteors, the velocities of these bodies sometimes exceed the parabolic limit described in the last chapter. If this be so, they must be wanderers through the infinite stellar spaces, having no connection with our system.

This is a very soft, faint light, surrounding the sun, extending out to about the orbit of the earth, and lying nearly in the plane of the ecliptic. In tropical latitudes it may be seen on any clear evening about an hour or