THE ELEMENTS AXD LIEE 389 



tubes, etc., chemistry could hardly exist ; while astronomy could 

 not have advanced beyond the stage to which it had Itecn 

 brought by Copernicus, Tycho Brahe, and Kepler. It rfu- 

 dered possible the microscope, the telescope, and the si)ectro- 

 scope, three instruments without which neither the starry heav- 

 ens nor the myriads of life-forms would have had their inner 

 mysteries laid open to us. 



One more example of a recent discovery of one of the rarest 

 substances in nature — radium — and its extraordinarv effects, 

 points in the same direction. So far as known at present, this 

 substance may or may not be in any way important either 

 to the earth as a planet or for the development of life upon 

 it ; but the most obvious result of its discovery seems to bo 

 the new light it throws on the nature of matter, on the con- 

 stitution of the atom, and perhaps also on the mysterious ether. 

 It has come at the close of a century of wonderful advance 

 in our knowledge of matter and the mysteries of the atom. 

 Many other rare elements or their compounds are now being 

 found to be useful to man in the arts, in medicine, or by the 

 light they throw on chemical, electrical, or ethereal forces.^ 



If now we take the occurrence of all these apparently use- 

 less substances in the earth's crust ; the existence in tolerable 

 abundance, or very widely spread, of the seven metals known 

 to man during his early advances towards civilisation, and the 

 many ways in which they helped to further that civilisation ; 

 and, lastly, the existence of a few elements which, when spe- 

 cially combined, produce a substance without which modern 

 science in almost all its branches would have been impossible, 

 w^e are broui2:ht face to face with a body of facts which are 

 wholly unintelligible on any other theory than that the earth 

 (and the universe of which it form> a part) was constituted 



1 While this chapter is being written I see it announced that two of the 

 rarest of the elements, lanthanium and noodyniuin. have l)ei'n found to pro- 

 vide (through some of their comjiounds) light-lilters, which increase the 

 efficiency of the spectroscope in <1h» study of the planetary atmospheres, 

 and may thus be the menus of still furthoi- extending oiu* knowledge of the 

 universe. 



