Chemistry and Physics, 55 
be of cast or wrought iron, steel, copper, brass, zine or lead. 
They must be completely immersed in the liquid used for plating, 
and their surfaces must be perfectly free from fat and rust. Iron 
vessels may be cleaned by treating with a solution containing 3 or 
4 per cent of chlorhydric acid. A sufficient quantity of a concen- 
trated solution of chloride of zine is now poured into the plating 
vessel, and from once to twice its volume of water added. The 
Solution is then to be heated to the boiling point, and chlorhydric 
mportant to remark th may be employed 
repeatedly for nickel-plating, especially when chloride of nickel is 
employed. The same process applies to cobalt, but the coating 
With this metal, besides its cost, possesses no practical value.— 
Polytechnisches Journal, cei, p. 145 (July, 1871). = Ww. G@ 
2. On the direct oxidation of carbon to mellitic acid.—At the 
recently held 44th meeting of German scientists and physicians, at 
Rostock, Prof. Schultze exhibited to the chemical section his beau- 
“process for the oxidation of carbon by hypermanganic acid, 
