42 SCIENCE AND IMMORTALITY 



tionSj repulsions, motions, and co-ordinations," 

 have been the chief concern of science. 



Dalton showed that the constant and definite 

 proportions in which the elements combined could 

 be best explained by assuming that the elements 

 consisted of certain indivisible ultimate particles 

 which had various definite weights ; and this hypo- 

 thesis unified, and simplified, and correlated so 

 many facts, that it has become the fundamental 

 fulcrum of practical science, and the physicist may 

 believe " that though he cannot handle or see 

 them^ the atoms and molecules are as real as the 

 ice-crystals in the cirrus clouds that he cannot 

 reach — as real as the unseen members of a 

 meteoric swarm whose death-glow is lost in the 

 sunshine, or which sweep past us unentangled in 

 the night " — that the atoms are in fact " not 

 merely helps to puzzled mathematicians, but 

 physical realities." ^ 



The discoveries to which the atomic theory has 

 led are legion ; and it has led not merely to dis- 

 coveries, but to creations ; for by its means 

 chemists have created substances which had never 

 appeared in the universe before. 



Let us try, now, to illustrate the modern concep- 

 tion of the atom. If we take a drop of mercury 

 and divide and subdivide it indefinitely, we get 

 mercury, and only mercury. If we had skill, we 



