of the minor planets. Why should we maintain that these planets must be inhabited, when the probability is, that the conditions of life are far more extreme than in the waste regions of the earth's surface? It is compatible with the scheme of Providence, that a large proportion of the earth's surface should be incapable of sustaining inhabitants. "Why should not a large portion of the solar system be barren too?
The purport of our remarks is simply to shew, that the analogical argument for a plurality of worlds is entirely based on a similarity of conditions, and that it can apply only to these bodies that approximate to the earth in regard to the conditions of life. The probability certainly is, that some of the bodies of the system, such as Mars, Jupiter, and Saturn, do not so far vary from the normal conditions as to render life improbable.
If we admit, what modern science has rendered extremely probable, that the sun and the various planets are all in a state of transition, passing from one phase of their history to another, the probability is that the other bodies must pass through stages corresponding to the present life-stage of the earth. From the past history of the earth, as shewn by geological history, and from its probable future destiny, as indicated by the law of solar heat and attraction, it is likely that only a comparatively brief cycle of its history is set apart for the display of the phe-
