HISTORY OF THE CONSERVATION OF ENERGY 109 



The principle of the conservation of energy has quite withstood all 

 attacks. To be sure, Le Bon claims to have overthrown it, too, 42 but 

 the validity of his argument is questionable. Even scientists some- 

 times play with logic. You have heard the story of the Assyriologist 

 who argued : " The Assyrians understood electric telegraphy, because 

 we have found wire in Assyria." " Oh," replied the Egyptologist, 

 " we have not found a scrap of wire in Egypt, so we know the Egyp- 

 tians understood wireless telegraphy." 



In the presidential address before the British Association in 1907, 

 Professor E. B. Lankester uttered the following weighty words : " The 

 kind of conceptions to which these and like discoveries have led the 

 modern physicist in regard to the character of that supposed unbreak- 

 able body — the chemical atom — the simple and unaffected friend of 

 our youth — are truly astounding. But I would have you notice that 

 they are not destructive of our previous conceptions, but rather elab- 

 orations and developments of the simpler views, introducing the notion 

 of structure and mechanism, agitated and whirling with tremendous 

 force, into what we formerly conceived of as homogeneous or simply 

 built-up particles, the earlier conception being not so much a positive 

 assertion of simplicity as a non-committal expectant formula awaiting 

 the progress of knowledge and the revelations which are now in our 

 hands." 43 



This same address touches questions of cosmical physics. It says: 



Radium has been proved to give out enough heat to melt rather more than 

 its own weight of ice every hour; enough heat in one hour to raise its own 

 weight of water from the freezing point to the boiling-point. . . . Even a small 

 quantity of radium diffused through the earth will suffice to keep up its tem- 

 perature against all loss by radiation! If the sun consists of a fraction of one 

 per cent, of radium, this will account for and make good the heat that is an- 

 nually lost by it. 



He continues to say: 



This is a tremendous fact, upsetting the calculations of physicists as to 

 the duration in past and future of the sun's heat and the temperature of the 

 earth's surface. The physicists, notably Professor Tait and Lord Kelvin, . . . 

 have assumed that its material is self-cooling. ... It has now, within these 

 last five years, become evident that the earth's material is not self-cooling, but 

 on the contrary self-heating. And away go the restrictions imposed by physi- 

 cists on geological time. They now are willing to give us not merely a thou- 

 sand million years, but as many more as we may want. 



Some of the views relating to radium, expressed in the summer of 

 1906 at the York meeting of the British Association, appeared to Lord 

 Kelvin open to objection. It seemed to him that some of the younger 



4= Le Bon, op. cit., pp. 17, 18, 53, 54. 



43 E. Ray Lankester, inaugural address before British Association, Nature, 

 Vol. 74, 1906, p. 325. 



