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Doctoring

This term is applied to plating defective places which occurred either by accident or negligence on the part of the operator. It is equally applicable to gold, silver or nickel plated articles. Take a piece of the anode, be it gold, silver or nickel, about the size of your little finger and connect it with the positive pole by a thin copper wire. Around this anode wrap a piece of ordinary muslin several times; hold the defective article on the top of the positive pole, and after dipping the anode in the solution until the muslin is thoroughly soaked, move it to and fro over the defective place, and a coating is thus formed.

Recovery of Gold from Bath. To recover gold from bath evaporate the bath to dryness, mix the residue with litharge and fuse the mixture. A lead button is thus formed in which all the gold is contained. Dissolve the button in nitric acid, and the gold will remain behind in the form of small flakes. Filter off and dissolve the flakes in aqua regia.

Recovering Gold from Coloring Bath. Dissolve a handful of sulphate of iron in boiling water, and add to it your "color" water; it precipites the small particles of gold. Now draw off the water, being very careful not to disturb the auriferous sediment at the bottom. You will now proceed to wash the sediment from all traces of acid with plenty of boiling water; it will require three or four separate washings, with sufficient time between each to allow the water to cool and the sediment to settle, before passing off the water. Then dry in an iron vessel by the fire and finally fuse in a covered crucible, with a flux.

Recovery of Silver from a Bath. To recover silver from cyanide bath; evaporate the bath to dryness, mix the residue with a small quantity of calcined soda and potassium cyanide and fuse in a crucible, and the metal will be found in the form of a button in the bottom of the crucible.