xiv THE ATOMIC THEORY 307 



are combined with one another ; " this was translated 

 info German and published as a series of papers in Gilbert's 

 Annalen, 1811-1812, and has been reprinted as No. 35 of 

 Ostwald's Klassiker. Admitting at once the truthfulness of 

 Proust's view that substances could only combine together 

 in a series of fixed proportions, he had already found in his 

 own work some evidence that these fixed proportions were 

 related together in a very simple way. Further experiments 

 on the same range of compounds that had been studied by 

 Proust enabled him to assert that 



" If two substances, A and B, combine with one another 

 in different ratios, this always takes place in the following 

 definite ratios: i A with iB (minimum); i A with ijB (or 

 perhaps more correctly 2 A with 36) ; lA with 26 ; lA with 

 46. In my experiments there is no example of lA with 

 36 " (Fixed Proportions, 1811-1812; Klassiker, XXXV. 5). 



The following cases were studied by Berzelius : 



Lead and Oxygen. 



Brown oxide ioo:i5'61 .. AA 



Yellow oxide 100 : 7-8 } Katw 2 : ' 



Sulphur and Oxygen. 



Sulphuric acid J 100 : 146 -427 \ ,, . . . 4Q7 . 

 Sulphurous acid ' 100 : 97-83 / Katl 1 497 ' ' 



Copper and Oxygen. 

 Black oxide 100 : 25 \ 



Red oxide IOO:I2'5/ 



Iron and Sulphur. 



100:117 

 Minimum 100 : 58 



Maximum 100:117 1 z> , 



73} Ratl 



Iron and Oxygen. 



Ferric oxide 100:44 '25! /> 4 i AQZ , 



Ferrous oxide 100 : 29-6 ) Katw 1>495 : ' 



In each of these cases, the exact analyses of Berzelius 

 enabled him to recognise the validity of the law of multiple 

 proportions, which had remained disguised in the rougher 

 analyses of Proust. 



1 i.e. sulphuric anhydride and sulphurous anhydride. 



X 2 



