48 Dr, Clark to Professor Mitscherlichy 



of Oxygen. The table gives first the compound of the 

 two protoxides (a x). 



A little study of the structure of this table, and considera- 

 tion of its contents, will evince, that, consistently with the 

 rule according to which it is framed, any two oxides, in com- 

 bining together so as to form neutral compounds — which 

 may be supposed the simplest sort of combination that can 

 take place between two oxides — ought to combine in such 

 proportions only that each oxide would contain an equal 

 quantity of Oxygen, How remote this is from the fact, it 

 were superfluous to say. Impossible, therefore, to be gene- 

 ral in its application, the supposed rule can only be regard- 

 ed as partial. But partiality is unlike a law of Nature, and 

 indeed the partiality disappears whenever we regard the 

 Oxygen-salts as having metals, and not oxides, for their 

 bases. The general formulas of the neutral Sulphates are 

 then tranformed, as follows : — 



A S =A S 

 AAS =A2S 

 A"S2=A I§2 



AAS3=A2S3 



* When taking this altered view of the Sulphates, a strik- 

 ing fact is is brought into light. So much of the Oxygen 

 as the common view regards as belonging to a , always, in 

 neutral salts, occurs exactly in the supplementary propor- 

 tion necessary to make up the acid-radical, S. Hence, ac- 



