HISTORY OF THE ATOMIC THEORY. 2 1 1 



great probability recognised by most chemists of the existence 

 of an order in which the elements are related to each other. 

 If this order should ever be found to be similar to that iTvhich 

 Richter has indicated, we must do the greatest honour to his 

 genius, although we cannot even now, when it stands before 

 us, say that it is a discovery, or that it has any value at all. 



The discovery of reciprocal proportion is given by no one 

 before Richter as far as I know, but he himself does not 

 speak of it as a discovery, but as a well-known fact, with 

 which he was familiar before he wrote his inaugural disserta- 

 tion. We find in the preface that it was well known that 

 neutral salts gave neutral results on decomposition ; this 

 Richter has put formally amongst the laws of stoechiometry, 

 and given it rank amongst chemical truths. He deduced from 

 it, as he himself says, that there must be ** distinct propor- 

 tionate quantities amongst the component parts of neutral 

 salts," and he strove hard to bring all combinations under 

 number and quantity. The knowledge of this fact seems to 

 have first set in motion his stoechiometry; instead then of 

 being the point which he gained, it is the point from which 

 he starts, according to his own account. He does not, 

 however, seem to have seen the reason for it, nor its general 

 bearing in chemistry, otherwise it could not have been left for 

 Fischer to shew that the combining number of an element 

 would fit its combination with every other element. 



The mode in which he obtains the relation of the combin- 

 ing weights of the earths to each other is remarkably self- 

 delusive, but at the same time exceedingly ingenious. They 

 are given at length, so that every one may compare for 

 himself. 



He endeavours to find out a similar relation between the 

 atomic weights of the alkalies, and readily does so. He is 

 led away by the numbers observed to mistake them for repre- 

 sentations of actual force, and so calculates in a relative and 

 abstract way the force needed for decomposition. This is 



