Nickel plating solutions are more difficult to manage than those of either copper, silver or gold. The amount of nickel salts held in the solution may vary considerably without materially affecting its working. From three to eight ounces of the combined salts per gal on of water makes a very good working solution. When it contains -less than this amount the working of the solution is retarded by the in¬creased resistence it offers to the passage of the electric current, and when it contains more than the proper amount, the chemical action is im-peded by the solution being too nearly satu¬rated. Electro plating is the product of electro chemical action, this phenomenon being called electro chemical action from the fact that a cur¬rent of electricity passing through a suitable liquid produces a chemical change in it. Elec¬tricity being the cause and chemical action the result, hence the importance of having a solu¬tion that is a good conductor of electricity and at the same time one that is capable of sustain¬ing the proper amount of chemical action neces¬sary for its successful operation. Nickel being a very brittle metal, it is rather difficult to obtain J suitable anodes. They are generally composed of plates of cast nickel, and should present a surface considerably larger than that of the articles to be plated. Where anodes of cast nickel cannot be obtained small fragments of nickel may be suspended in the solution by means ol a frame work of platinum wire.
Nickel is a metal that is seldom obtained in its pure state. It generally containing traces of copper, carbon and other impurities which, dis¬solving with the anode, are either deposited or fall to the bottom and form a black sediment. It is a difficult matter to obtain a heavy deposit of nickel, owing to its tendency to crack and scale off, but for ordinary work there is no par¬ticular necessity in having a thick deposit, as% it is so extremely hard that a very thin coating will, with ordinary usage, last for years where a deposit of silver equally as thick would scarcely last as many months. Nickel is not affected to any great extent by exposure to the air or coal smoke, and in this respect it possesses an ad-vantage over silver which is easily tarnished by exposure to sulphuretted gases. Nickel is very easily corroded by acids and iorms very poison¬ous compounds, and for this reason should never be used, for plating the interior of vessels used in cooking ; but for plating such articles as cream pitchers, sugar bowls, drinking cups, etc., it possesses the great advantage of being capable of retaining its polish and resisting rough usage for a long time.
From one to three cells of battery will gener¬ally be sufficient; too much battery causing the metal to be deposited in the form of a black powder. The anode, either in the form of a plate of nickel, or composed of fragments of nickel suspended in a platinum wire net work, should be attached to the wire leading from the copper pole of the battery, and the previously cleaned articles, after being placed in the^splu-tion, should be attached to the wire leading from the zinc pole of the battery and kept in gentle but constant motion and as near as pos¬sible to the anode without coming in actual con¬tact with it, until they have acquired a sufficient
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deposit, when they may be taken out and well rinsed in hot water and dried by rolling them about in hot sawdust. All the solutions we have given should be used at a temperature of from^ioo0 to 1500 Fahr.
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