earth by those bodies which are set on fire and then gradually extinguished."
Dr. Good thus refers to temporary stars: "Worlds and systems of worlds are not only perpetually creating, but also perpetually disappearing. It is an extraordinary fact, that within the period of the last century, not less than thirteen stars, in different constellations, seem to have totally perished and ten new ones to have been created.
"In many instances it is unquestionable that the stars themselves, the supposed habitation of other kinds or orders of intelligent beings, together with the different planets by which it is probable they were surrounded, have utterly vanished, and the spots which they occupied in the heavens have become blanks."
Burritt thus describes the changes in colour observed in Tycho's star: "At first appearance it was of a dazzling white, then of a reddish yellow, and lastly of an ashy paleness in which its light expired." "It is impossible," says Mrs. Somerville, "to imagine anything more tremendous than a conflagration that could be visible at such a distance." The collision theory seems the best one to account for such phenomena, but the imagination and senses alike fail in any attempt at a realisation of the heat generated by the impact, or the magnitude of the ensuing conflagration.
