One of the successful applications of Electro-Metallurgy is founded on the original application of it by Mr. Spencer. As already stated, he covered metal plates with wax, and after scratching through the coating, and exposing the metal, he submitted the plate to voltaic action in a solution of sulphate of copper, and thus obtained a representation, in relief, of the figures cut through the wax; but he does not seem to have thought of the application of this mode of deposition, since adopted, by which engravings in relief are obtained, and printed from with the ordinary letter-press, in the same manner as woodcuts. The name given to this new art is "Glyphography," and it is used with great advantage when the effect of copper-plate engraving is required; for cross lines, which are difficult to cut in wood, can be worked by this method with as great facility as in copper-plate etching. Another application of Electro-Metallurgy that promises to be useful, is the coating of glass and earthenware vessels with copper, so as to enable them to be placed over the fire without being cracked. A glass sauce-pan might thus be made, which, protected by metal covering, would neither break nor crack when placed upon the fire, because the metal would diffuse the heat over the whole surface, and prevent the unequal expansion of the vessel, which is the cause of the cracking of glass and earthenware when placed upon the fire. A patent was granted last year for a mode of coating earthenware vessels with copper or iron by electro-chemical deposition. The earthenware is first covered either with copper leaf or with bronze powder, to obtain an electrical conducting surface on which the copper can be deposited, and the vessel is then placed in a solution of sulphate of copper, and put in connection with the negative pole of a voltaic battery. The electrotype is frequently applied with advantage to the preservation and multiplication of objects of art and natural productions, for even the forms of flowers may be in this manner rendered durable; but the most important use that has been made of the process is in plating and gilding. To effect that object, it is necessary to employ a voltaic battery separated from the vessel in which the decomposition takes place. The annexed diagram shows an arrangement of this kind. A single cell of a Daniell's battery, _a_, is connected by wires from its positive and negative poles, with metal rods placed across the decomposition cell, _b_. The articles to be plated are suspended by wires from the metal rod, _f_, and a plate of silver is attached to the rod, _e_. Thus, when the vessel is filled with the silvering liquid, a voltaic current is established, and the deposition is effected on the articles connected with the negative pole. [Illustration]