51 



In some instances I obtained the same bronze or gold- 

 like substance by treating copper vanadiate suspended in 

 water with sulphurous acid gas, and in many otliers the 

 effect of the gas was formation of vanadic oxide in solution. 

 I intend to elucidate this point by further experiments. 



The copper vanadiate was prepared by precipitation of 

 ammonium vanadiate with copper sulphate. The mother 

 liquor contained both copper and vanadic acid. After 

 evaporation the latter is found in the residue as meta- 

 vanadic acid, with the same metallic appearance as that 

 just described, and can be obtained by washing with water. 

 The crystals obstinately retain copper, sometimes as much 

 as 12 per cent, which is best removed by repeated treatment 

 with aqueous sulphurous acid. A sample of the substance 

 so prepared was analysed by Professor Roscoe with the 

 following results : 



Weight of substance taken 0.4505 gram. 



Loss on ignition ... 0.0411 „ 



Hence the per centage composition is found to be 



Water 9.12 



Vanadium pentoxide 90.88 



100.00 



The samples of vanadium bronze obtained by these three 

 different methods had the same composition, the same 

 appearance, and the same chemical properties. It is essen- 

 tially distinguished from the amorphous brick-red hydrated 

 vanadic acid by its indifference to reagents. Sulphurous 

 acid scarcely acts on it, neither does ammonia, and even a 

 solution of sodium carbonate dissolves it only after very 

 long continued boiling. In the air it is perfectly perma- 

 nent. It is very probable that this meta-vanadic acid will 

 become a favorite bronze, valued even higher than gold. 



