120 G. F. BECKER — RELATIONS OP RADIOACTIVITY TO COSMOGONY 



it essential for tlie geologist to reckon with the contribution to terrestrial 

 heat which the dissipation of this energy involves. 



Again, the gaseous" nature of the emanations is indubitable, as well as 

 that they are soluble in water, and thus a means is provided of transfer- 

 ring radioactivity from one geological formation to another almost 

 without limit. The disintegration theory in its present shape can only 

 be accepted with reserve until it is shown that Sir William Eamsay's 

 neon and argon were not of radioactive origin, and the method which 

 the disintegration theory affords of determining the age of minerals must 

 be cautiously applied under checks by other methods. It seems highly 

 probable that the "mineralizing^' action of radioactive substances will be 

 found extremely important, both in ore deposits and among a certain 

 class of rocks. 



Origin' of Uranium and Thorium 



The discovery of radium surprised the world, but professional chemists 

 were astonished rather at the special properties of the "element" than at 

 the instability of an atom. It was, to be sure, pretty generally supposed 

 by those who were without special knowledge of chemistry that the so- 

 called elements were independent entities, but from the days of Lavoisier 

 and Dalton philosophical chemists have declined to pin their faith to this 

 idea. Lavoisier himself was familiar with "radicles," or groups of atoms, 

 which enter into combination as if they were simple substances. Ammo- 

 nium, the amids, and cyanogen are familiar examples; indeed, among 

 organic substances compound radicles are not the exception, but the rule. 

 If elements could combine to groups which behaved like simple sub- 

 stances, it necessarily followed that the chemical relations of elements 

 were not distinctive, and that substances as yet unresolved might prove 

 complex. The idea of a fundamental relationship among the elements 

 first gained prominence in 1815, through Front's hj^othesis, namely, that 

 all the atomic weights were multiples of that of hydrogen, which almost 

 amoimted to assuming that hydrogen was Eoger Bacon's "protyle," '■' 

 Urstoff, the one truly simple substance. Many of the great series of 

 atomic weight determinations made during the first half of the nineteenth 

 century were undertaken with the express purpose of testing Prout's 

 hypothesis. They disproved it, but the idea of a protyle did not die. In 

 1851 J. Dumas ^* boldly asserted his belief in the transmutability of 



" This term was revived by Sir William Crooke's. Proceedings of ttie Royal Institu- 

 tion, 1887, vol. 12, p. 37. 



1^ An address delivered at the Ipswich meeting of the British Association for the 

 Advancement of Science, but not included in the report. See American .lournal of Sci- 

 ence, vol. 12, 1851, p. 275. 





