SHEFFIELD PLATE, the name applied to a variety of articles of domestic use or ornament, made of copper coated with silver by a special and now abandoned process. Many of them were actually manufactured in Birmingham, but as the secret of producing the material was discovered and brought to perfection in Sheffield, the name of that town was naturally connected with it, and thence transferred to articles constructed from it.
In 1742 a workman named Thomas Bolsover was mending the handle of a knife made of silver and copper, when, accidentally overheating it, he caused the metals to fuse and flow, and found that as a consequence the silver adhered to the copper as a thin coating. Being an intelligent man, he perceived the commercial value of his chance discovery, and began the manufacture of articles which, with all the appearance of silver, were both cheaper and stronger than those made of the pure metal. He apparently, however, confined himself to applying the silver direct to the surface of the copper after the latter had been given the shape destined to it, and was thus limited to the production of small articles such as snuff-boxes, knife handles, toilet articles, etc. It was reserved to Joseph Hancock to realize that by making the plate first and working it into the desired form afterwards he could almost indefinitely extend the possibilities of the material. The process in its final and highest development was as follows. The groundwork was a mixture of copper and brass, either metal alone having serious defects. This was cast into an oblong ingot, i to i\ in. in thickness, 2^ in. in breadth, and of a length regulated by the size of the plate desired. The surface of this was brought by planing, grinding and other means to the highest possible pitch of smoothness and evenness. A sheet of silver of a finer quality than standard, ranging in thickness from fa in. to nearly i in. according to the quality aimed at, and of the same superficial extent as the copper bar, was levelled and polished in the same way and accurately fitted to it, neither surface at any time being soiled by contact with the workman's fingers. A sheet of copper, rather smaller than the other two and fa in. thick was laid upon the silver, and on the top of all was added a piece of iron, i in. thick, i in. wide, and a little shorter than the three others, to protect them from the direct contact of the strong iron wire with which all were firmly bound together. The junction of the edges of the silver and copper-blend was treated with a flux of borax and the whole was submitted to the heat of a furnace until the silver was seen to be melting, when it was instantly removed, care being taken to avoid pressing upon the upper or lower surfaces, as the liquid silver in that case would have been squeezed out from between the two enclosing plates and the operation ruined. It was then left to cool, and after being thoroughly cleansed presented the appearance of a copper ingot with one silver side. This was passed again and again between gradually approximated rollers, with occasional annealing, until the desired thickness had been attained. The great extension of surface thus produced had the drawback of exaggerating any small defect in the union of the two metals, increasing it to a blister of an inch or more in diameter. It was, however, fortunately found easy to remedy this. The blister if unbroken was heated, pricked, and then rubbed level with a burnisher; if, as sometimes happened, the silver had flaked away it was replaced by coatings of pure leaf silver rubbed in with a burnisher. The plate when passed as flawless was cut into the desired form and moulded as far as possible into shape, the edges where necessary being soldered. At first only one surface of the copper was plated with silver and thus its usefulness was necessarily restricted, but it was a simple matter to apply the silver to both sides and thenceforward whatever was made in solid metal could be reproduced in plate, and firm after firm went into the business, ever and anon introducing further improvements. The possibility of embossing the metal beyond a certain point without fracturing the coating of silver was got over by casting or stamping the raised ornament in silver, filling the hollows with a form of pewter and soldering the result to the appropriate part of the general design. Another difficulty, the concealment of the inner core of copper which was seen as a thin red line when a cut edge was exposed, was met about 1784 by George Cadman, who adopted the practice of soldering on an edging, generally ornamented, of solid silver so as to cover the junction, and the presence of this is one of the trustworthy tests by which genuine Sheffield plate may be recognized. The labour of rolling the metal by hand was done away with about 1760, by the firm of Tudor, Leader & Sherburn, who first employed horse-power, and for more than half a century the trade both in Sheffield and Birmingham continued to flourish. In 1736 there were under 10,000 inhabitants in the former city; in 1760 when Horace Walpole passed through it, buying for two guineas a pair of candlesticks of the local plate, which he thought " quite pretty," and pronouncing it to be " one of the foulest towns in England," there were two-and-twenty thousand who remitted eleven thousand pounds a week to London. It would be impossible, were it desirable, to enumerate all the varieties of the articles turned out, or to overpraise the beauty and elegance of most of them. The designs were identical with those in favour with the gold- and silver-smiths of the period, which was happily one when exceptionally good taste prevailed. The appreciation of light and well-proportioned curves and the skilful employment of well-contrived pierced work are conspicuous features.
The success was, however, doomed to be short lived and to come to an end as swiftly as it had grown up. In the year 1800 W. Cruikshank was already experimenting with a process of electro-plating, and in 1837 Mr Spencer in England, and in 1838 Professor M. H. Jacobi (1801-1874) in Russia, working independently, succeeded in contriving methods which could be made commercially profitable. Two years later Messrs Elkington in London and M. de Ruolz of Paris started in business on those lines, and the slower and consequently more costly manufacture at Sheffield and Birmingham rapidly died out.
Of recent years old Sheffield plate after long neglect has come into fashion again, and genuine articles in good condition have greatly gone up in value, often exceeding in cost those of more modern date in sterling silver. Concurrently fraudulent imitation has regrettably increased. In some cases the whole object is a modern reproduction in electro-plate, but more often really old articles from which the original plating has been worn off in course of time have been replated, both equally being in the eyes of the connoisseurj unworthy of serious attention and comparatively valueless. The difference after a little experience is not difficult to detect, though inexpressible in words. The pressure to which the Sheffield plate was submitted produces a definite colour and texture which is absent from the surface produced by the deposit of silver in a liquid medium by electrical means, and the coat of silver is spread by the latter uniformly over the whole surface without a break, while in the former the junction between the embossed ornaments and the silver strips covering the cut edges may often be detected on careful examination.
See Sheffield Plate by Bertie Wyllie; H. N. Veitch, Sheffield Plate: its history, manufacture and art (London, 1908). (M. BE.)
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)