CHAP. XII.] MOLECULES. 359 



and yet this light, which is to us the sole evidence of the 

 existence of these distant worlds, tells us also that each of 

 them is built up of molecules of the same kinds as those 

 which we find on earth. A molecule of hydrogen, for 

 example, whether in Sirius or in Arcturus, executes its 

 vibrations in precisely the same time. 



Each molecule therefore throughout the universe bears 

 impressed upon it the stamp of a metric system as distinctly 

 as does the metre of the Archives at Paris, or the double 

 royal cubit of the temple of Karnac. 



No theory of evolution can be formed to account for the 

 similarity of molecules, for evolution necessarily implies con- 

 tinuous change, and the molecule is incapable of growth or 

 decay, of generation or destruction. 



None of the processes of Nature, since the time when 

 Nature began, have produced the slightest difference in the 

 properties of any molecule. We are therefore unable to 

 ascribe either the existence of the molecules or the identity 

 of their properties to any of the causes which we call natural. 



On the other hand, the exact equality of each molecule 

 to all others of the same kind gives it, as Sir John Herschel 

 has well said, the essential character of a manufactured 

 article, and precludes the idea of its being eternal and self- 

 existent. 



Thus we have been led, along a strictly scientific path, 

 very near to the point at which Science must stop, not 

 that Science is debarred from studying the internal mechan- 

 ism of a molecule which she cannot take to pieces, any more 

 than from investigating an organism which she cannot put 

 together. But in tracing back the history of matter, Science 

 is arrested when she assures herself, on the one hand, that 

 the molecule has been made, and, on the other, that it has 

 not been made by any of the processes we call natural. 



Science is incompetent to reason upon the creation of 

 matter itself out of nothing. We have reached the utmost 

 limits of our thinking faculties when we have admitted that 

 because matter cannot be eternal and self-existent it must 

 have been created. 



