Page:Popular Science Monthly Volume 73.djvu/113

Rh The principle of the conservation of energy has quite withstood all attacks. To be sure, Le Bon claims to have overthrown it, too, but the validity of his argument is questionable. Even scientists sometimes 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 Egyptians 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 unbreakable 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 elaborations 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."

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 temperature 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 annually 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 physicists on geological time. They now are willing to give us not merely a thousand 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