Vlll PKEFACE 



earnest thought, of extensive reading, and of help 

 from contemporary workers and thinkers. It is 

 practically the work of a life time. 



There can be no doubt that the key by which the 

 orderly phenomena of Nature can be unfolded lies in 

 the hands of the physicist ; hence the whole of the 

 work is built up from physical phenomena. 



The work is based on the author's previous book, 

 "What is Heat?" Indeed, it is the sequel to that 

 work. 



The style adopted is that of an advocate pleading 

 for truth, in the simplest of language. The case is 

 first stated, and the evidence is afterwards brought in. 

 The reader must always bear in mind that the author 

 is only a special pleader, and may fail in obtaining 

 a full verdict of " Proven." A negative verdict can 

 only be obtained by the existence of strong negative 

 evidence. 



The conception of eternal molecular regeneration is 

 the key to the solution of the problem of the pene- 

 tration of the "unknowable"; it is the rope which 

 lifts the Veil. When one grasps the stupendous 

 stretch of time required to explain the simplest 

 geological phenomena, one is impressed with a sense of 

 security that the infinite terrestrial future will be 

 as certain as (to our minds) the infinite past. 



The struggle which the human being has passed 

 through in the process of attaining to his present 

 -condition, which is a process of brain -perfecting, 



