Zinc is cleansed by being passed through a boiling solution of caustic lye, without remaining too long in it, because it may be corroded, and even dissolved; after rinsing, it is plunged for a few minutes into water containing 10-20 per cent. sulphuric acid, then rinsed in plenty of warm add 7 02. sulphuric acid at 66° B., and 1 ox. of amalgamating salt; or the zinc may be amalgamated with metallic mercury, after it has been cleansed in dilated sulphuric acid, by being dipped into mercury, or rubbed over with this metal by means of a scratch-brush of brass wire. Pat the zinc cylinder into the stoneware pot; then introduce the cylinder of carbon into the porous cell; fill the empty space between the carbon and the sides of the cell with nitric acid at 36-40° B.; place the porous cell thus filled into the centre of the zinc cylinder. The surfaces of the two liquids should be level.
When several elements are to be connected, they are. placed near each other, without touching, and the first carbon or graphite is left free for the attachment of the anode. The ribbon or band of the first zinc is pinched between the jaws of the brass binding screw, and the carbon of the second element, and so forth, until the last zinc is ready to be connected with the object to be electro-plated.