296 SALTS 



The water actually present in our analysis of this 

 mass exceeded 6 atoms by rather less than half 

 an atom. Had the action of the acid continued 

 for a little longer, we should probably have ob- 

 tained the exact atomic quantity contained in 

 the preceding table. The small surplus water 

 was doubtless lodged mechanically in the pores 

 of the dry mass. 



Carbonate, 3. Carbonate of lime. This well known min- 

 eral, when pure, is anhydrous. It may, indeed, 

 contain a little water lodged mechanically be- 

 tween the plates of the crystals ; but such, when 

 it exists, is very small, and is easily driven off by 

 exposing the salt to a moderate heat. Its con- 

 stituents are 



1 atom carbonic acid 2*75 



1 atom lime . 3'5 



6-25 



When carbonate of lime is rendered soluble in 

 water by means of carbonic acid gas, a bicarbo- 

 nate is formed, which seems only capable of ex- 

 isting in solution, at least, I have never suc- 

 ceeded in obtaining it in a concrete state. Per- 

 haps if it were crystallized under great compres- 

 sion this bicarbonate might be obtained. 

 Phosphate, 4. Phosphate of lime. This salt can only be 

 formed artificially in the state of a white powder. 

 It is neutral, insoluble, and anhydrous, being 

 composed of 



