for an extremely brief part of its entire history, say, for example, for about one-thousandth-part of the entire number of years during which our globe has had an independent existence, so we may fairly conjecture that the occupancy of any other world by intelligent beings might be only a very minute fraction in the span of the planet's history. It would, therefore, be highly improbable, to say the least of it, that in two worlds, so profoundly different in many respects as are this earth and Mars, the periods of occupancy by intelligent beings should happen to be contemporaneous. I should therefore judge that, though there may once have been, or though there may yet be, intelligent life on Mars, the laws of probability pronounce against the supposition that there is such life there at this moment.
We have also heard surmises as to the possibility of the communication of inter-planetary signals between the earth and Mars, but the suggestion is a preposterous one. Seeing that a canal, sixty miles wide and a thousand miles long, is an object only to be discerned on exceptional occasions, and under most favourable circumstances, what possibility could there be that, even if there were inhabitants on Mars who desired to signal to this earth, they could ever succeed in doing so? We are accustomed to see ships signalling by flags, but what would have to be the size of the flags by which the earth could signal to Mars, or Mars signal to the earth? To be effective for such purpose each of the flags should be, at least, as big as Ireland. It is true, no doubt, that small planets would be fitted for the residence of large beings, and large planets would be proper for small beings. The Liliputians might be sought for on a globe like
