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Rh perennial source of energy. Many competent physicists have expressed the opinion that the mechanical difficulties of such a boring as would be necessary are insuperable. No one, however, would venture to prophesy, in such a matter as this, that what is prevented by insuperable obstacles to-day may not be within our powers in the course of a few years.

Such audacious control of the resources of our planet is suggested as a possibility, a legitimate hope and aim, by recent observations and speculations as to our neighbour, the planet Mars. I do not venture to express any opinion as to the interpretation of the appearances revealed by the telescope on the surface of the planet Mars, and indeed would take the most sceptical attitude until further information is obtained. But the influence of these statements about Mars on the imagination and hopes of Man seems to me to possess considerable interest. The markings on the surface of the planet Mars, which have been interpreted as a system of canals, have been known and discussed for many years. It has recently been observed that these canals undergo a recurrent seasonal change of appearance consistent with the hypothesis that they are periodically filled with water, which is derived from the polar snow-caps of the planet at the season of greatest polar heat. It is suggested that Mars is inhabited by an intelligent population, not necessarily closely similar to mankind, but, on the contrary, unlike mankind in proportion as the conditions of Mars are unlike those of the Earth, and that these inhabitants have constructed by their own efforts the enormous irrigation works upon which