COMPOUND SALTS, CONTAINING 



ture is left to spontaneous evaporation a trans- 

 parent colourless salt gradually appears, crystal- 

 lized in long prisms, apparently four-sided but 

 rather indistinct. These crystals do not affect 

 litmus or cudbear paper ; they have a disagree- 

 able taste bearing a certain resemblance to that 

 of sulphate of zinc. As the whole of the liquid 

 shoots into these crystals, it is evident, that the 

 compound salt consists of an integrant particle of 

 tartrate of alumina and an integrant particle of 

 carbonate of soda united together. From the 

 weight of the compound salt, compared with that 

 of the two constituents, it was easy to infer that it 

 contained 9 atoms water. Hence, the constitu- 

 ents of the salt are 



1 atom tartrate of alumina 10-5 

 1 atom carbonate of soda 6-75 



9 atoms water . . 10-125 



2. Magnesio-carbonate of lime. The mineral 

 known by the name of dolomite, when amor- 

 phous, and of rhombspar or bitter spar, when in 

 crystals, is too well known to require any parti- 

 cular description. If any confidence can be put 

 in Klaproth's analyses, there are two distinct 

 species of this mineral : 



(1.) The common dolomite and magnesian 

 limestone, are composed of 



