50 URANIUM, ANTIMONY, CHROMIUM, & C . 



mate and 12%5 grains of chromate of potash is 

 just the same. The only difference between the 

 two salts is, that the former contains two atoms 

 of chromic acid while the latter contains only 

 one. It is evident from this, that the difference 

 Atom of between 19 and 12*5, which amounts to 6*5, 



chromic 



acid. must represent the weight of an atom of chromic 

 acid. 



Chromate of potash is composed of 



1 atom chromic acid = 6-5 



1 atom potash = 6 



12-5 



Bichromate of potash consists of 







2 atoms chromic acid =13 

 1 atom potash = 6 



19 



3. Now, as there are three oxides of chro- 

 mium, the probability is, that the atomic weight 

 of chromium is 3*5, and that the three oxides 

 are composed as follows : 



CHROMIUM. OXYGEN. ATOMIC WEIGHT. 



Protoxide of 1 atom + 1 atom 4-5 

 Deutoxide 1 atom + 2 atoms 5-5 

 Chromic acid 1 atom + 3 atoms 6-5 



The protoxide combines readily with the dif- 

 ferent acids ; but I have not been able to ob- 

 tain any of the salts which it forms in the state 



