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OFFICIAL DESCRIPTIVE AND ILLUSTRATED CATALOGUE.

factures lias achieved a more complete triumph, andhas been more generally adopted, than that of electro-metallurgy. In little more than twelve years from theperiod in which it was announced to the public as a philo-sophic and scientific amusement in the copying of coins,medals, or woodcuts, it has assumed a position the mostimportant in the industrial world. Other discoverieshave had their periods of infancy, childhood, and middlenge—they have crept slowly on to their prime—but the artof the electrotype appears to have sprung up at once intovigorous life and usefulness. Its discovery is due toThomas Spencer, of Liverpool; although Jacobi, of St. Petersburg , a Russian professor, also lays claim to it.Upon it has been founded all the various improvementswhich have finally resulted in the present advanced stateof the art. As such it gives employment to many thou-sands of workmen; it has superseded the older modes ofplating, and it has, to a great extent, relieved gildersfrom the horrid disease and suffering consequent uponthe old methods of gilding by amalgam, and resultingfrom the injurious effects of the mercurial vapour, whileit has greatly increased the facility with which original,or copies from celebrated works of art, may be produced.It has no limits to the delicacy of its working or themagnitude of the works produced; it will preserve orcopy the down on an insect's wing, or produce a life-sizestatue, as in that of Geoffrey de Mandeville, shown inthe Exhibition, and now forming a principal ornament inthe House of Lords . It has been truly said that tbe domeof St. Paul’s might be gilt, and a man-of-war copperedby the electric agency. There are no limits to its capa-bilities, save that of the size of the vessel to hold the solu-tion, and the power of the battery or magnetic-machineto generate and supply the electricity.

In its simplest form, electro-metallurgy may be de-scribed as a process in which a substance held in solution isdeposited in a metallic form upon some metal to be eoatedor form to be copied. In the last, the east or mould hasbeen rendered conducting, by being covered with a me-tallic substance, or some material for which the metal heldin solution has an affinity. Black-lead is the mineralmost commonly used. The electricity employed was gene-rated in the early period of the art by means of a galvanicbattery in various forms. The loss of zinc and othermetals was, however, great, and the battery was finallysuperseded (though at times still used) by the electro-magnetic machine, described in the preceding notice.This is a comparatively cheap process, requiring littlemore cost save the repairs of the machine and that of tbeengine which sets it in motion. Of thirty patents takenout for improvements in electro-metallurgy, thirteen havebeen originated in Birmingham , and these have hadreference to the most important steps of progress in theart. It was at one time held that composite metals couldnot be deposited: brass lias, however, been successfullythrown down, but the cost, far exceeds any advantagegained by the deposit. Gutta percha, sealing and otherwaxes, stearine, plaster of Paris, &e., have been employedin the composition of moulds for internal deposits, but arecent discovery has been made of an elastic mould whichmay be left in the deposit trough without injury, andproduce the most exquisite details and the most compli-cated under-cuttings. The mould may be removed with-out injury, and used repeatedly. It had previouslybeen customary to place copper upon a prepared mould,thereafter to destroy the plaster, and deposit a preciousmetal, gold or silver, therein; then to remove tbe coppercoating or matrix by disintegration from its more precious

internal lining, when the object desired was exposed. Thebeneficial effects of electro-metallurgy have not been con-fined to the art of working in metals only, its influence hasbeen extended to calico-printing, in the manufacturing ofrollers for embossing and printing surfaces; copper andsteel plates have been copied by its agency: woodcutshave also had their fac-similes produced thereby ; whilea new mode of illustration, viz., glyphography, owes itsexistence tto it. This enables the artist to produce, bya process in its early stage similar to etching, a metalsurface with lines in relief, which may be printed fromby the printing-press; and when blocked up into form inconnection with ordinary type, it is equally efficient withwood-engraving, while it is less liable to injury. Allthese important results owe their existence to the acci-dental recognition, in the first instance, that the metaladhering to the copper-plate of a galvanic-battery depo-sited thereby was a copy, even to its most minute mark-ings, of the plate to which it adhered. The experi-ments of Spencer, and the improvements of others, havelaid the superstructure of an art whose future, judgingfrom the progress made in the past, cannot be wellimagined.

Though rather more suitable, in its present form, forthe workers in iron than those engaged in the manipula-tion of the more precious metals, it may not be out ofplace to direct attention to the steam hammer of Nasmyth,of which a modification is introduced into Messrs. Elking-ton’s works. It is one of the most beautiful applianceswhich the advanced state of science has placed in thehands of the manufacturer. By an arrangement producedby means of perpendicular screws, which in turn operateupon the valves, and regulate the admission of steam,the power of the blow may be so regulated that an eggmay be tapped so gently that though touched it suffersno injury, while the next blow may as readily be madeto crush into form a huge mass of iron or other metal.The action of the hammer depends upon that of the ordi-nary steam-engine, viz., a piston working in a cylinder.Though as yet only generally adopted by those engaged inthe iron trade, its introduction into every department ofmetal-working cannot fail to lighten the artizan of themost laborious portion of his toil, and by doing so, in acorresponding ratio, increase his power by the facilitieswhich it affords for the production of works of magnitudein metal, and at a reduced cost.

The “ autogenous blowpipe ” is a useful and valuableauxiliary to tbe worker in metals, from the facility andease with which the flame may be directed to any partof the work to be soldered. The nozzle of the blow-pipe is formed by two tubes placed concentrically, theouter of which being connected by a flexible tube to theordinary gas-pipe which supplies the works, and thecentre pipe also by a flexible tube to a pair of bellows ora blowing-machine, the gas is ignited, and the stop-cockconnected with the blow-pipe turned on : the flame is pro-pelled with great force upon the parts of the article to beunited; the solder being mixed with borax, speedilyfuses under the influence of the heat, the force or fusingpower of which is increased or diminished by regulatingthe supply of air or gas. Complete control is maintainedover the action of the flame by means of tbe stop-cocks.It is usual, in order to economise the heat, to place thearticle to be soldered on a raised pan filled with coke.-'W. C. A.]

“ Elkington, Mason, &, Co., Newhall Street, Binning'ham (1, p. (!71). Messrs. Elkington and Mason are th®first who introduced into England the application of the