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Preface.
vii

absolutely, in this his Earth-life, what the life of other worlds may be.

Probably the best conception of this matter is that suggested by Messrs. Nasmyth and Carpenter, in their valuable work on the Moon, where they say, "Is it not conceivable that the protogerms of life pervade the whole universe, and have been located on every planetary body therein?" In the Moon, circumstances seem to be unfavourable to life; but it is a mere begging the question to assume that this is the law of every orb in heaven save this earth of ours.

In the following tale or speculation (as you choose to take it), although apparently I have given no rein to the imagination, yet I have endeavoured to avoid as much as possible any conflict with established scientific discoveries; and, indeed, have based my speculations on the