An object intended to receive a plating of copper need not be of metal at all; it may be of any material, so long as it possesses a conducting surface. A mold or a cast made of any plastic material, such as wax or cement, may have its surface made conductive by the application of graphite, finely pulverized carbon, or metal dusts held on by some medium not soluble in water. The wax molds, or impressions of type and cuts, are dusted with plumbago, and then suspended in the copper solution. A wire from the negative pole is connected so as to come in contact with the plumbago, and the copper deposit immediately begins to form on the face of the wax. When the film of copper has become heavy enough, the mold is drawn out of the solution, and the thin shell of metal removed from the wax and cut apart, so that each shell is separated from its neighbor and freed from marginal scraps. Flowers, leaves, laces, and various other objects can be given a coat of copper by thus preparing their surfaces, and some most beautiful effects may be secured by copper-coating roses; then placing them for a short time in a gold bath, and afterwards chemically treating the surface plating so as to imitate Roman, Tuscan, or ormolu gold, in bright or antique finish. Coins, medallions, bas-reliefs, medals, and various other things are reproduced by the electro-plating process, and their surfaces finished in gold, silver, bronze, or other effects. Years ago this was not possible, because the old method was to make a fac-simile cast in metal of the object desired, and then chase or refinish the surface. This was a costly and tedious task. When Brugnalelli, an Italian electrician, electro-gilded two silver coins in 1805, he laid the foundation for the modern process, but it did not come into general use until about 1839, when electro-plating and the electro-depositing of metals was begun on a practical scale. Before the invention of the dynamos for generating current, batteries had to be employed, and this made the process somewhat more expensive than the present method. Our boy amateurs, however, will have to be content with the battery system, since they are not supposed to have access to direct-current power, such as is used for arc or street lighting. Various forms of batteries may be used for this work, and they will be described in detail. For the copper-plating bath it will be necessary to have the anodes of soft, cast, or sheet, copper sufficiently heavy so as not to waste away too quickly. These should be of the proper size to fit within the bath, and either one large one or several small ones may be employed. Stout copper bands should be riveted to the top of the plates, by means of which they may be hung on the bar and so suspended in the solution (Fig. 10). The contact-points should be kept clean and bright, so that the current will not meet with any resistance in passing from the rod to the plates.