272 HISTORY OF MINERALOGY. 



betrays its unsoundness. The electro-positive prin- 

 ciple was, in a very short time after its adoption, 

 proved and acknowledged to be utterly untenable : 

 what security have we that the electro-negative 

 element is more trustworthy ? Was not the neces- 

 sity of an entire change, of system, a proof that the 

 ground, whatever that was, on which the electro- 

 chemical principle was adopted, was an unfounded 

 assumption ? And, in fact, do we not find that the 

 same argument which was allowed to be fatal to the 

 First System of Berzelius, applies in exactly the 

 same manner against the Second ? If the electro- 

 positive elements be often isomorphous, are not the 

 electro-negative elements sometimes isomorphous 

 also ? for instance, the arsenic and phosphoric acids. 

 But to go further, what is the ground on which the 

 electro-chemical arrangement is adopted ? Granted 

 that the electrical relations of bodies are important; 

 but how do we come to know that these relations 

 have anything to do with mineralogy? How does 

 it appear that on them, principally, depend those 

 external properties which mineralogy must study ? 

 How does it appear that because sulphur is the 

 electro-negative part of one body, and an acid the 

 electro-negative part of another, these two elements 

 similarly affect the compounds ? How does it appear 

 that there is any analogy whatever in their functions? 

 We allow that the composition must, in some may, 

 determine the classified place of the mineral, but 

 why in this way? 



