CHEMICAL COMBINATION 31 



water is formed. Two atoms of hydrogen have rushed 

 into union with one of oxygen, to yield a molecule of 

 water. The formula H 2 is used to indicate this. In 

 hydrochloric acid (HC1) one atom of hydrogen combines 

 with one of chlorine, in ammonia (NH 3 ) three atoms of 

 hydrogen unite with one of nitrogen. 



The compounds of the same elements in different pro- 

 portions, as in N 2 0, NO, N 2 3 , N 2 0, N 2 5 , are substances 

 of entirely different properties. 



When, then, an atom is examined, it is found to be 

 innnitesimally small, to be weighed, measured, and shaped 

 with inconceivable nicety. As far as it was concerned, 

 it might have stood alone in immensity. There might 

 not have been another existing ; but, lo ! another atom, 

 innnitesimally small also, and similar to it. Even these 

 two exquisitely cut gems, if we could perceive them, 

 would compel us to say, Here are clear marks of mind. 

 It is evident that the hand of intelligence has given to 

 these atoms their characteristics, and made them alike. 

 But when we find that there are not only two or three 

 alike, not only millions or centillions, but numbers for 

 which there is no name, the certainty that their likeness 

 is due to mind becomes overwhelming. But we find also 

 another kind of atom, different in every respect, and 

 multitudes like it, multitudes beyond all numbers, and 

 these in like manner proclaiming that their wondrous 

 order is due to a skilful hand ; and when two of these 

 atoms are brought together in appropriate circumstances, 

 they draw close to each other, they form a new molecule, 

 revealing new qualities. And in the same circumstances, 

 the myriads of the atoms of the one combine with the 

 myriads of the atoms of the other. But there are not 

 merely two, but nearly seventy kinds ; and all the atoms 

 of each and every kind are characterised by the force of 



