442 COMPOUND SALTS, CONTAINING 



This must be acknowledged a very curious com- 

 bination. It might be called a ditartrate of pot- 

 ash and antimony ; for 1 atom of tartaric acid 

 must be combined with 2 atoms of protoxide of 

 antimony, while the other atom of acid is divid- 

 ed between the atom of potash and the remaining 

 atoms of protoxide of antimony. 



] 7. Sulpho-chromate of potash. This salt was 



chromateof . . , 



potash. obtained by mixing together solutions of chro- 

 mate of potash and sulphate of potash, in the 

 proportion of 3 atoms of the former to 1 atom of 

 the latter. On concentrating the mixture and 

 setting it aside, the first crystals which were 

 deposited had a greenish yellow colour, and 

 were either in octahedrons or four-sided rectan- 

 gular prisms terminated by four-sided pyramids. 

 These last were obviously the regular octahe- 

 dron with a prism interposed between its pyra- 

 mids. The crystals were small, but very regular 

 and transparent ; the taste was saline and bitter ; 

 and the salt was not very soluble in water. When 

 this salt was heated to redness it became opaque, 

 but did not lose any weight, it was therefore 

 anhydrous. After some unsuccessful attempts 

 to analyze this salt by means of tartaric acid it 

 was treated in the following way : 



78*5 grains of it were dissolved in water, and 

 precipitated by a neutral solution of protonitrate 

 of mercury. The precipitate being edulcorated, 



