58 THE ADVANCE OF SCIENCE 



gous properties ; each successive series 

 starting with a body the atomic weight of 

 which is greater than that of any in the 

 preceding series, in the following fashion : 



This is a conception with which biolo- 

 gists are very familiar, animal and plant 

 groups constantly appearing as series of 

 parallel modifications of similar and yet 

 different primary forms. In the living 

 world, facts of this kind are now under- 

 stood to mean evolution from a common 

 prototype. It is difficult to imagine that 

 The pos- in the not-living world they are devoid of 

 of V Y significance. Is it not possible, nay prob- 

 Form a o7 able, that they may mean the evolution of 

 matter. our i e i emen t s ' from a primary undifferen- 



