42 THE KINGDOM OF MAN 



16. AN UNTOUCHED SOURCE OF ENERGY. 



The applications of steam and electricity have so far 

 astonished and gratified the rebel Man, that he is some- 

 times disposed to conclude that he has come to the end 

 of his power of relieving himself from the use of his 

 own muscles for anything but refined movements and 

 well-considered health-giving exercises. One of the 

 greatest of chemical discoverers at this time living, 

 M. Berthelot, has, however, recently pressed on our 

 attention the question of the possibility of tapping the 

 central heat of the earth and making use of it as a 

 perennial source of energy. Many competent physicists 

 have expressed the opinion that the mechanical diffi- 

 culties of such a boring, as would be necessary, are 

 insuperable. No one, however, would venture to pro- 

 phesy, 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. 



17. SPECULATIONS AS TO THE MARTIANS. 



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 neigh- 

 bour, 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, 



