Page:Astronomy for Everybody.djvu/306

comet is disintegrated in the manner described in the last chapter, those portions of its mass which are not completely dissipated continue to revolve around the sun as minute particles, which get gradually separated from each other in consequence of there being no sufficient bond of attraction, but they still follow each other in line in nearly the same orbit.

The same thing was found to be true of the August meteors. They are found to move in an orbit very near to that of a comet observed in 1862. The period of this comet could not be exactly determined, but it is supposed to be between one and two hundred years.

The third remarkable case of this kind occurred in 1872. We have already spoken of the disappearance of Biela's comet. It happens that the orbit of this body nearly intersected that of the earth at the point which the latter passes toward the end of November. From the observed period of this comet it should have passed this point about the first of September, 1872, between two and three months before the passage of the earth through the same point. From the analogy of the other cases it was therefore judged that there would be a meteoric shower on the evening of November 27, 1872, and that the radiant point would be in the constellation Andromeda. This prediction was fulfilled in every respect. The Andromedes, as these meteors are called, now recur with great regularity.

There are now some disappointing circumstances to narrate. The comet of 1866 should have reappeared sometime during the years 1898-1900, but it was not