375 



carbonic acid as a mere solvent, and reports neutral, or 

 common carbonate of lime. Again, if sulphuric and carbonic 

 acids, soda, and lime, are present in small proportions, 

 chemically equivalent to each other, it is possible that one 

 chemist may report the presence of 



Sulphate of soda (40 and 32) 72 



Carbonate of lime (22 and 28) 50 



Total 122 



Another might state the composition to be — 



Carbonate of soda (22 and 32) 54 



Sulphate of lime 68 



Total 122 



Their totals agree, their acids and bases are the same. 

 These are matters of direct experiment, in which ordinary 

 correctness will secure uniformity ; but from difference in 

 their opinions as to the grouping of the acids and bases, 

 the salts mentioned are quite different : neither of those 

 which composed the total in each is mentioned in the other. 

 The determination of that point, the furnishing a decisive 

 victory to either class of opinions, is not by any means at 

 present within our reach, or, to all appearance, likely ever 

 to be so within the range of direct experiment : the question 

 is one of inference and probabilities. The practical conse- 

 quence of this disagreement is, that, as in the above instance, 

 salts may be stated to be present in one report, which are 

 wholly absent from the other. If such salts are present in 

 any other than chemical equivalent proportions, the quantities 

 will be modified : thus we might have 



Sulphate of soda 72 



Carbonate of Urae (50 and 20) 70 



Total 142 



