54 URANIUM, ANTIMONY, CHROMIUM, c . 



the escape of chlorine ; but these experiments, 

 though not absolutely exact, are sufficient ap- 

 Atom of proximations to satisfy us that the atomic weight 

 ttndprotox.of chromium is 3%5, and that of the prptoxide 

 4%5 ; and consequently, that it contains only 1 

 atom of oxygen combined with an atom of chro- 

 mium. 



SThr <^ de ' The brown oxide, as usually prepared, neither 

 mous add, combines with acids nor bases : yet it may be 

 made to combine with alkalies, and to form with 

 them a soluble compound. This was ascertained 

 in the following way : on a quantity of chromate 

 of soda in crystals I poured some alcohol, and 

 digested the mixture : the yellow colour disap- 

 peared and the salt became green, owing to the 

 conversion of the chromic acid into protoxide of 

 chromium. This green matter was evaporated 

 to dry ness, and digested repeatedly in nitric acid 

 it assumed the colour of deutoxide of chromi- 

 um. The whole was then evaporated to dryness 

 to get rid of the nitric acid, and the residual 

 brown matter was dissolved in water : I obtained 

 a dark brown opaque liquid, which I concen- 

 trated as much as possible, and then set aside in 

 order to obtain crystals ; but none would form. 

 The salt in this opaque liquid was obviously a 

 combination of deutoxide of chromium and soda. 

 It might, therefore, be called chromite of soda : 

 probably the other chromites might be obtained 

 by a similar process. 



