very wide range, even in this globe, in the conditions necessary to sustain life. Still, we must start from some essential conditions of life in this globe, if we are to make our argument one of analogy. No doubt, it may be said that God could, in the case of the planetary bodies, make life dependent on totally different conditions. This is true, but it is a totally different question from that of analogy. The question is one, not of possibility but of probability, and the probability is to be derived from the existence of conditions in the moon, similar to those in the earth. While ignorant of the absence of air and water in the moon, the many other points of similarity would afford some presumption that the moon is inhabited. But these points of similarity militate against the presumption, now that the essential conditions of life on our globe are found to be wanting. If it be held that life may be sustained by totally different means, then the hypothesis is best sustained by finding points of difference instead of similarity.
Let us take one of the most essential conditions of life on our globe, the existence of air: air is less essential to some creatures than to others, but we have no reason to believe that, under a total deprivation of it, any creature can exist on our globe. It may be argued, that God could create beings capable of existing without air, and that life may exist in the moon, even though no atmosphere should be discovered. The question is, however, not, What is within the com-
