78 URANIUM, ANTIMONY, CHROMIUM, &c. 



lustre, and assumed the appearance of 'an opaque 

 white matter like chalk ; but at this temperature 

 the whole water of crystallization was not driven 

 off; the salt was, therefore, exposed to a red 

 heat. The loss of weight was 11 -25 grains. 

 Now, 11 '25 is equivalent to 10 atoms of water. 



(2.) The salt, thus rendered anhydrous, was 

 digested for a long time in water acidulated with 

 muriatic acid. The whole was then thrown on 

 a filter ; and the columbic acid, after being well 

 washed, dried, and heated to redness, weighed 

 19 grains. 



(3.) The muriatic liquid was saturated with 

 carbonate of ammonia, gradually evaporated to 

 dryness in a platinum crucible, and the dry mass 

 which remained exposed to a heat sufficient to 

 expel the sal-ammoniac which constituted the 

 principal part of it. There remained a quantity 

 of common salt, which weighed almost exactly 

 7*5 grains. This is equivalent to 4 grains of 

 soda. 



From this analysis it appears, that the crystals 

 of columbate of soda are composed as follows : 



Columbic acid . 19 

 Soda . . 4 



Water 11-25 



34-25 



4 is equivalent to an atom of soda, and ] 1-25 to 

 10 atoms of water. As the salt renders cudbear 



