To plate sheet lead with a thin film of copper first prepare the following solution. Dissolve l1b. of copper sulphate in 1/2 gal. of rainwater, then stir in enough liquor ammonia to throw down the copper in the form of a green precipitate, and dissolve this to make a blue liquid. Dilute this with an equal bulk of rain-water, then add sufficient potassium cyanide to destroy the blue tint and produce the colour of old ale. Filter the whole through calico and expose to the action of air for twenty-four hours, when it should be ready for use. Work it cold or hot with a strong current at a pressure of from 6 to 8 volts, using an anode plate of pure copper. The lead plates must be scoured clean with sand and water, then briskly rinsed in a solution of pearlash (l1b. to the gallon), and transferred from this direct to the copper-plating solution without handling or previous rinsing in water. If the first deposit is coarse and loose, remove the plates and well brush them in -suiter with a hard fibre brush, again rinse in the potash or pearlash solution, and return to thj copper-plating bath, using a reduced anode surface, or keep the plates moving whilst being plated. In this way a bright facing of copper may be obtained, which mast be well rinsed and dried quickly to prevent tarnishing.

Electro-deposited copper rapidly tarnishes in air when damp.