orbits only one out of a very large number can intersect the track of the earth even when due allowance has been made for the effect of perturbation. It therefore follows that out of all the missiles projected from Ceres, only very few could be expected to reach the earth, even after the lapse of an indefinitely great time.
This examination of the conditions under which bodies projected from Ceres could fall to the earth as meteorites, has shown that such a source for these bodies is highly improbable. In the first place, it has been demonstrated that the immediate object sought to be gained by locating the volcano on a small planet would not be realised, for a very high velocity would be necessary on account of the circumstances of the situations of the orbits in the solar system. We should, therefore, in any case need volcanoes with tremendous power even if placed on so small a globe as Ceres. It is further shown, that even if this highly improbable condition could be fulfilled, the volcanoes on Ceres would be so badly adjusted for the work to be done that they would miss a large number of shots for every one that was successful. These improbabilities are so great that we are forced to reject the hypothesis which implies them, especially when, as we shall see in the next chapter, we can point out a locality for the volcanoes to which no such improbability attaches. I need not go into details with regard to the other planets. Setting aside all other objections the large ones would require tremendous volcanoes to drive the missiles free from the attraction of their globes; and there is besides the further circumstance, that there will be in every case an enormous preponderance of missiles which can never pass through the earth's track, over those which may happen to do so.
