24 SCIENCE PROGRESS 



there is a real discrepancy between the atomic disintegration 

 exemplified by radioactivity, the only type of which we have 

 any definite knowledge, and that which is implied by the 

 spectroscopic classification of stars and nebulae. In the latter, 

 the evolution of the elements would seem to proceed from 

 simple elements of low atomic weights, to more complex 

 elements of high atomic weights, the transformation being 

 attended by an emission of energy. In the case of radioactive 

 disintegration, on the contrary, complex elements of high atomic 

 weights break down with emission of energy into simpler 

 elements with lower atomic weights. Applying the law of 

 reaction to radioactive processes, it would be deduced that the 

 parent elements, uranium and thorium, should be stable at 

 sufficiently high temperatures, thus implying that they ought to 

 be characteristic elements in certain classes of stars, and in 

 any case, that they would there be less unstable than under 

 terrestrial conditions. Spectroscopic analysis indicates that in 

 stars of the hottest class, hydrogen and helium appear to be the 

 chief components. In stars of a less high temperature, oxygen, 

 nitrogen, and carbon appear. Silicon comes next, and finally, 

 at a much lower temperature, iron, manganese, calcium, and 

 other metals, including uranium, are introduced. Either the 

 spectroscopic evidence of the temperature and constitution of 

 the stars is insufficient and misleading, or Le Chatelier's law, in 

 so far as it refers to temperature changes alone, is not applicable 

 to the radioactive transformations. As a third alternative by 

 which the dilemma may be avoided, it may be suggested that 

 radioactivity is not primarily controlled either by temperature 

 or pressure, but by other physical conditions, possibly electro- 

 magnetic, in some way of which we are as yet entirely ignorant. 

 It is conceivable, for example, that the forms of hydrogen and 

 helium which exist in the hottest stars, may be very different 

 from the familiar terrestrial forms, so that they may represent, 

 either intrinsically or in virtue of their environment, an even 

 higher concentration of energy than the radioactive atoms. In 

 such a case it would be possible for the high temperature 

 elements to condense, with evolution of energy, to form the 

 radioactive elements as well as the more stable elements of 

 terrestrial conditions. Any changes of this kind, however, 

 could not be referable to temperature conditions alone, and it 

 seems impossible that they could take place in the interior of the 



