Intelligence and Miscellaneous Articles, 397 



Fig. 3. — Front view of the meter in an 

 ornamental case. 



ACTION OF SULPHUROUS ACJD ON METALLIC OXIDES. 



The following are the results of experiments on the action of sul- 

 phurous acid on metallic oxides by M. Vogel. 



1st. Red oxide of mercury at first becomes protoxide combined 

 ■with sulphurous and sulphuric acids, and is afterwards completely 

 reduced to the metallic state by sulphurous acid. 



2nd. Pernitrate of mercury is slowly reduced by sulphurous acid, 

 but the reduction becomes perfect with the aid of heat ; the protoni- 

 trate is reduced in the same manner, but more rapidly. 



3rd. Bichloride of mercury is not reduced, under the same cir- 

 cumstances, by sulphurous acid, lower than to protochloride ; and 

 ■when the solution of the bichloride is mixed with a sufficient quan- 

 tity of sulphurous acid, it is not decomposed by the caustic alkalies 

 added in excess ; the mercury remains in solution in the alkaline 

 liquor. 



4th. Protochloride of mercury is not reduced to the metallic state 

 by sulphurous acid, but merely to a subchloride of mercury ; but 

 subpersulphate of mercury (turbith mineral) is entirely reduced by 

 sulphurous acid. 



5th. Neither oxide nor nitrate of silver is completely reduced by 

 sulphurous acid. 



6th. The oxides of zinc, antimony and uranium, do not suffer the 

 slightest reduction by sulphurous acid. 



7th. The black oxide of copper calcined and left in contact with 

 sulphurous acid, becomes brown protoxide, and the acetate of the 

 oxide becomes acetate of suboxide when heated ; the greater part 

 of the copper being deposited in the state of brown suboxide. 



8th. Sesquioxide of iron when calcined does not yield any of its 



