Alpacca Silver: An alloy that resembles sterling, but contains only copper, zinc, and nickel.
Annealing: The heat treating (softening) of metal after it has been work-hardened with steel tools, and is necessary between raising and forging stages. Annealing is also used to remove tension in a piece of metal before brazing, helping to reduce warpage.
Argentium Sterling: A new firestain-free alloy with fantastic tarnish resistance. It contains a higher percentage of fine silver (93%, and the higher 97% fine silver). It can be stamped sterling. More on Argentium can be found here.
Assay: It is impractical for a refiner to refine each individual shipment of scrap separately. To keep the operation efficient, a sample is taken of each refining shipment to determine its precious metal content. Drilling samples are taken from each end of the bullion. The assay laboratory does a miniature refining process on the two samples to determine the precious content. The bullion karat is actually determined by the percentage of fine gold left following the assaying process. For example, 2-100 milligram samples are taken. The samples are wrapped in lead, placed onto cupels and put into a special assay furnace. As the samples become molten, the base metals, including the lead, vaporize or absorb into the cupels, leaving only the precious metal on top. The precious metal buttons are dissolved in the acid so that the gold content can be determined. The remaining samples are reweighed. If the 100 milligram samples now weigh only 50 milligrams, this means that there is 50% fine gold in the bullion.
Blistering: This occurs when a base metal or precious metal object that is plated with fine silver is overheated, detaching itself from the underlying metal resulting in a surface like the below (notice the fine blistered texture covering the chasing).
Brass:An alloy consisting primarily of copper, usually with zic as the additional metal.
Brazing:Ajoining process whereby a filler metal or alloy is heated to melting temperature above 800 °F and distributed between two or more close-fitting parts by capillary action. At its liquid temperature, the molten filler metal and flux interacts with a thin layer of the base metal, cooling to form a strong, sealed joint. By definition the melting temperature of the braze alloy is lower (sometimes substantially) than the melting temperature of the materials being joined. The brazed joint becomes a sandwich of different layers, each metallurgically linked to the adjacent layers.
When brazing sterling, care must be used to prevent firescale or firestain which is formed at higher temperatures than soldering.
Bright-cutting: A form of engraving which uses polished gravers to produce very reflective cuts.
Britannia Silver: An alloy of silver containing 95.84% silver, with the balance usually copper. This standard was introduced in England by Act of Parliament in 1697 to replace sterling silver as the obligatory standard for items of "wrought plate." The lion passant gardant hallmark denoting sterling was replaced with "the figure of a woman commonly called Britannia," and the leopard's head mark of the Worshipful Company of Goldsmiths replaced with a "lion's head erased."
Britannia standard silver was introduced by the English government as part of the great recoinage scheme of William III from 1696, when attempts were made to limit the clipping and melting of sterling silver coinage. It was thought that by maintaining a higher standard for plate, there would be less incentive to put the newly issued sterling coins in the melting pot.
Sterling silver was approved again for use by silversmiths from 1 June 1720, and thereafter Britannia silver has remained an optional standard for silver assay in the United Kingdom and Ireland. Since the hallmarking changes of 1 January 1999, Britannia silver has been denoted by the millesimal fineness hallmark 958, with the symbol of Britannia being applied optionally.
The silver bullion coins of the Royal Mint issued since 1998, known as "Britannias" for their reverse image, are minted in Britannia standard silver.
Britannia silver should be distinguished from Britannia metal, a pewter-like alloy containing no silver.
Bronze: An alloy consisting primarily of copper, usually with tin as the additional metal.
Casting: A manufacturing process by which a liquid material is (usually) poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solid casting is then ejected or broken out to complete the process. Casting is most often used for making complex shapes that would be otherwise difficult or uneconomical to make by other methods.
Chasing:The technique of detailing the front surface of a metal article by indenting with various hammer-struck punches. This process does not remove metal, but reshapes it. Chasing is demonstrated here. This technique is demonstrated in the second part of the video. See an example of a chased Tiffany teapot here.
Checking: The hammering down onto the edge of a form. This technique strengthens and visually thickens the edge. See this piece.
Coin Silver: Sterling is 925/1000 parts pure silver and is a legally enforceable standard as of 1868. Coin was more variable; the purity of metal matching, in theory, that of contemporary currency. Occasionally, during periods of shortage, coins were literally used as metal stock, especially in the colonial era. Because of the multiplicity of coinage in use, it has varied from 835/1000 to 925/1000. It was never an enforceable standard like sterling, but was a means for silversmiths, lacking a national standard of assay, to assure clients of the quality of their silver. By the 1820s, with flat-rolled silver stock readily available, it became an arbitrary benchmark set at 900/1000 and remained so until the British sterling standard was adopted by Tiffany, and others in the 1850s. Gorham switched to the .925 standard in 1868 to compete with British-made silver.
Colloidal Silver: A liquid suspension of microscopic particles of silver. A colloid is technically defined as particles which remain suspended without forming an ionic, or dissolved solution. The broader commercial definition of "colloidal silver" includes products that contain various concentrations of ionic silver, silver colloids, ionic silver compounds or silver proteins in purified water. Colloidal silver with concentrations of 30 parts per million (ppm) or less are typically manufactured using an electrolysis process, whereas colloidal silver with higher concentrations of 50 ppm or more are usually either silver compounds such as silver chloride and silver iodide or are solutions that have been bound with a protein to disperse the particles.
Currently, colloidal silver is marketed as an alternative medical remedy, though there is no scientific evidence of its effectiveness for any medical condition. Excessive use can result in argyria, a form of silver toxicity.
I. History and Applications
Prior to 1938, colloidal silver was widely promoted as a "cure-all," and silver products were prescribed by physicians as topical antibiotics. However, with the development of more effective, less expensive antibiotics such as penicillin and sulfanilamide, medical use of colloidal silver ceased. From approximately 1990, there has been a resurgence of the promotion of colloidal silver as an alternative medicine treatment, marketed with claims that it can prevent or treat numerous diseases.
Colloidal silver products are legally available at health food stores in the United States and Australia and are marketed over the Internet as a dietary supplement. It is illegal in the U.S. and Australia for marketers to make claims of medical effectiveness for colloidal silver, but some websites still list its use for the prevention of colds and flu, and the treatment of more serious conditions such as diabetes, cancer, chronic fatigue syndrome, HIV/AIDS, and tuberculosis, among other diseases. Colloidal silver has been found to lack any antimicrobial effect, and there is no medical evidence that colloidal silver is effective for any of these claimed indications. Silver is not an essential mineral in humans; there is no dietary requirement for silver, and no such thing as a silver "deficiency."
Currently, there are no evidence-based medical uses for colloidal silver. There are no clinical studies in humans demonstrating effectiveness, and several reports of toxicity. The U.S. National Center for Complementary and Alternative Medicine has issued an advisory indicating that the marketing claims made about colloidal silver are scientifically unsupported, and that the silver content of marketed supplements varies widely and can pose risks to the consumer.
II. Toxicities and Interactions: Argyria
Excessive intake of silver products may result in a condition known as argyria, one symptom of which is blue or gray discoloration of the skin. The discoloration occurs when silver is deposited in the skin and then darkened by sunlight, just as silver particles in photographic film darken when exposed to sunlight. Localized argyria can occur as a result of topical use of silver-containing remedies, while generalized argyria results from the ingestion of colloidal silver. Arygria is usually permanent, and there is no known effective treatment. While argyria is usually benign and limited to skin discoloration, there are isolated reports of more serious neurologic, renal, or hepatic complications. A death has been reported in the medical literature as a result of colloidal silver use; in that case, a 71-year-old man developed status epilepticus which the authors felt was due to silver toxicity.
A number of case reports describe argyria after ingestion of colloidal silver marketed as an alternative-medicine treatment. Colloidal silver may theoretically interact with some medications, including tetracycline and quinolone antibiotics and penicillamine, reducing the effectiveness of those medications.
III. Government Regulation
In August 1999, the U.S. Food and Drug Administration (FDA) banned colloidal silver sellers from claiming any therapeutic value for the product, noting that such products were being marketed for numerous diseases without evidence of effectiveness. The FDA also banned over-the-counter sale of drug products containing colloidal silver due to the lack of safety or efficacy data. The product now has the status of a dietary supplement in the US; it can be promoted with general "structure-function" claims, but cannot be marketed as preventing or treating any illness.
Following this ruling, the FDA has issued numerous warnings to Internet sites which have continued to promote colloidal silver as an antibiotic or for other medical purposes.
In 2002, the Australian Therapeutic Goods Administration (TGA) ruled that colloidal silver-containing products were no longer exempt from therapeutic goods legislation and had to meet the requirements of other products covered by this law. The TGA found that "there are no current legitimate uses of colloidal silver and that the Surveillance Section of the TGA be requested to investigate the illegal availability of colloidal silver products because of concerns about their significant toxicity. The reasons for the recommendation were that:
There is little evidence to support therapeutic claims made for colloidal silver products; the risk to consumers of silver toxicity outweighs the value of trying an unsubstantiated treatment, and bacterial resistance to silver can occur; and efforts should be made to curb the illegal availability of colloidal silver products, which is a significant public health issue.
Coin Silver: Coin silver may have a variety of marks or may not be marked at all. Coin silver originally was made from melting coins from various countries. These coins were minted using varying grades of silver. The U.S. adopted a 900/1000 standard for American silver coinage in 1837, but as silversmiths continued to use predominantly foreign coins to make their silver goods, the actual silver content of coin silver objects can vary.
The word Dollars on silver indicates an object was made from melted silver dollars, so is coin silver.
The word Standard used on silver indicates it was made to the U.S. silver standard after 1837, so 90% pure. Please note, however, that the word Standard can also be used on silverplate to indicate something altogether different.
Due to the Assay Act of 1814 passed in the State of Maryland, a mark of the Baltimore Coat-of-Arms or the numbers 10-15, 10 oz 15, 1015, 11, 11 oz, or 11-12 also are an indication of coin silver.
Conservation: Primarily dealing with cleaning an object, doing the least amount of harm to its original finish.
Crimping: A rapid raising process by forming radiating valleys from the center to the outer edge of a metal object then raised. Generally used on thinner gauge metal.
Cross-Peen Hammer: Hammers with long, narrow faces running perpendicular to the handle and used for raising, forming, and planishing.
Depletion Gilding: Term used for producing a pure gold surface on an object by dissolving the copper in the alloy with acid. A more accurate term for gold alloys is, for example: "18K gold, surface copper depleted." For sterling and other silver alloys: "sterling, surface copper depleted."
Die Forming: The process of stamping or hammering a sheet of metal into a form which has the outline of the object. Also used when making duplicate objects.
Drawbench: A narrow, waist-high bench equipped with a chain dragging a pair of drawtongs (large coarse-toothed pliers) used to grip the end of a piece of wire. This wire is then pulled through a series of consecutively smaller dies (round, square, triangular, etc.) reducing its thickness. Patterned dies may also be used to produce moldings, boarders, etc. See a drawbench here.
Duty Mark: (also called Sovereign's Mark): A mark that appears on English silver and gold from 1784-1890 which signifies a tax was paid to the crown.
Electroforming: The process of growing a metalic object over a mandrel or into a mold.
Electroplating:Italian Luigi V. Brugnatelli invented electroplating by electrolysis in 1805. But, it wasn't until the 1840s that John Wright of Birmingham, England, discovered a more commercial process of electroplating using potassium cyanide. George Richards Elkington and Henry Elkington of Birmingham England – two cousins who began their research during the industrial revolution – bought the patent rights from Wright and were given the first patent for electroplating in the 1840s.The process of putting a metallic coating on a metal or other conducting surface by using an electric current. It is used to improve the appearance of materials, for protection against corrosion, and to make plates for printing.
The process: The article to be plated is thoroughly cleaned of grease and dirt by dipping it in acid and alkaline cleaning solutions. It is then put in a solution of the metal with which it is to be coated. The metal exists in the form of positive ions (atoms that have lost one or more electrons). The article is connected to the cathode (negative end of a source of electricity). The anode (positive electric terminal) is connected to another conductor which is also dipped into the solution. The electric current acts on the metallic ions in the solution. The ions are attracted to the cathode, and the coating is deposited on the article's metal surface. If the metal in the solution and the metal of the positive terminal are the same, the electricity may remove metal from the terminal to replace metal taken from the solution.
The thickness of the layer deposited on the article depends on the strength of the electric current, the concentration of metallic ions, and the length of time the article has been in the solution. The terms triple-plated and quadruple-plated indicate various thicknesses of plating, not separate layers deposited on the surface.
Ornamental and protective platings are very thin, usually from 1/1,000 to 2/1,000 of an inch (0.03 to 0.05 millimeter) thick. For plating gold, silver, copper, zinc, and cadmium, cyanide solutions of the same metals are often used. Copper and zinc may also be plated by acid-sulfate solutions. Chromium is plated with a chromic-acid solution and nickel is plated with nickel sulfate. Other metals plated for commercial use include platinum, lead, and tin. Alloys of two or more metals may be deposited by using a solution of salts of the metals that make up the alloy. Examples of alloys used for plating are brass, black nickel, lead-tin, and bronze.
Electroplating is also used to reproduce medals or other objects in a process called electroforming. This process was formerly known as galvanoplasty. One kind of electroforming, called electrotyping, is the reproduction of type forms and engravings for the printing industry.
Resource: Melvin Bernstein, "Electroplating," Discovery Channel School, original content provided by World Book Online, http://www.discoveryschool.com/homeworkhelp/worldbook/atozscience/e/177500.html, 11/15/2001
Electrum: A naturally occurring alloy of gold and silver, with possible trace amounts of copper and other metals.
Engine Turning: An engraving technique in which a very precise intricate repetitive patterns or design is mechanically engraved into an underlying material with very fine detail. It is engraving on a two- or three-dimensional surface with a diamond stylus cutting very specific designs, mostly linear. You've probably seen examples engine turning on card cases, money clips, and dresserware. Engine turning is also called guilloché after the French engineer “Guillot,” who invented a machine “that could scratch fine patterns and designs on metallic surfaces.” Engine turning machines were first used in the 1500-1600's on soft materials like ivory and wood and in the 1700's it was adopted for metal such as gold and silver. The last machines were manufactured around 1948-1949. The machine improved upon the more time-consuming practice of making similar designs by hand, allowing for greater delicacy, precision, and closeness of the line, as well as greater speed.
Engraving: The process of cutting shallow lines into metal with a sharp graver, reproducing artwork which has been drawn on a metal article. Unlike machine engraving, hand engraving removes metal when cutting. See a video here. A fantastic engraving glossary can be found here.
EPNS: Electro Plated Nickel Silver.
Etching: A process of dissolving metal with acid, leaving a recessed design. The upper, unetched surface is sometimes engraved.
EuropeanRulers:An abridged list from the Metropolitan Museum of Art includes kings and queens whose rule affected the arts of Europe in important ways and whose names are most commonly raised in art historical discussion. See the list here.
Firestain:Oxidized copper (shown as the dark, blotchy areas on the tankard below) in solid silver can be found on many pre-colonial through early twentieth century pieces. If after cleaning your silver (not silverplate) piece a purplish stain remains, do not mistake this stain (cuprous oxide) for tarnish! Attempting to remove it will only damage your prized piece. It is not generally seen on pieces that have been produced by the large American silver companies after the early 1900s, but many one-person silversmithing shops still use this technique. I will not get into the technicalities of firestain here, except to say that the stain is usually obscured with fine silver either by silver plating the object or through a process called depletion. The firestain under this fine silver layer, which may be a few thousandths of an inch thick, may not show up until after many years of polishing.
Fold Forming: Fold forming is a new, quick, easily learned way of shaping sheet metal with hand tools. Forms are derived from the natural plasticity and ductility of the metal. Lewton-Brain invented fold-forming, which is internationally recognized as a new way to work metal. Shaping is extremely efficient and rapid (many take 3-7 minutes working time). Tools are simple: fingers, hammers, anvil, and mill. Complex relief forms are made from sheets of metal often on one annealing. They resemble chased, constructed, and soldered forms, and can be made with most metals, including steel.
Forging: A process that has as its primary purpose: the alteration of the original thickness and cross-section of metal. This is usually through hammering wire, rods of metal, ingots (as would be forged into sheet by modern day Colonial Williamsburg silversmiths), or heavy sheet stock (for forming most flatware).
Forming: A process which has as its primary purpose: altering a sheet of metal so that it changes planes, three-dimensionally. Changes in the metal's thickness are incidental by-products of the process of forming.
THE Goldsmiths' Company of London was incorporated in the year 1327, and ever since that time there have existed laws against the making of counterfeit silver. This company not only assays and hall-marks London-made silver, but it also has the right to destroy spurious articles, and inflict f1nes upon those who have done the counterfeiting.
At one time, in England, to forge plate was punishable with death, although we do not understand that this penalty was ever enforced. However, we do know that in the year 1597 two goldsmiths who produced some counterfeit silver were put in the pillory, and each had one ear cut off.
It is not proposed to enter into the consideration of the penalties that are now imposed for counterfeiting, but to state briefly the different modes of forging plate, and the means whereby one can detect such frauds. In ancient times base metals were sometimes plated and sold as solid silver. This is seldom, if ever, done at the present time. Prior to the 1st of October, 1844, 22-carat gold wares and silver articles were hall-marked with the same marks. This uniformity of marks on the two metals was taken advantage of to defraud the public by gilding a silver piece of plate and then selling it for gold. To remedy this, a law was passed in 1844 which changed the hall-marks on gold - a crown with the figure 22 was introduced in place of the lion.
For many years silver articles have been made below the standard, and the hall-marks surreptitiously placed upon them. From 1784 to 1890, when there was a tax upon every piece of silver that was made, the Goldsmiths' Company collected the duty, indicating that it had been paid by placing upon the silver the mark of the sovereign's head. This duty at times was eighteen pence an ounce. To avoid paying it, the scheming silversmith would place (by means of counterfeit punches) the hall-marks on his own silver. This temptation to avoid taxation was removed in 1890 by the abolition of the duty. Before this was done, it was easier to convict a counterfeiter of plate, for then there were two charges on which to precede against him, namely, fraud and the evasion of taxes.
Frauds may be considered under the following heads: Subtractions, Additions, Transformations, Transpositions and Counterfeit Marks.
By the term subtraction is meant the removal of a portion of silver from an article after it has been hall-marked; as the foot from a paten in order to make it into a salver, or a spout from an urn to change it into a cup. Although in some cases this is a form of deception, it is believed that no prosecution at law would succeed where a subtraction has been made.
Under this heading are classed hall-marked articles to which additions have been made by the silversmith. The law says that consent must be obtained of the authorities before making an addition, and that if the change increases the weight of the article to more than one-third of its original weight the added silver must be hall-marked. But the addition should not change the character of the article; a foot, a handle or a spout may be added, but not so that it changes the use of the article; thus one must not alter a tankard into a coffee-pot. The commonest forms of additions are as follows:
(1). An old and rare article is plated inside to increase its weight, after which gilding is used to hide the newness of the plating. Where an old piece of plate is worth ^1o ($50) an ounce (old silver is almost always sold by the ounce in England), one can readily see the temptation to increase the weight.
(2). A pierced border is often added to a plain salver in order to make it more attractive and salable. When this is done the designing silversmith does not have the border marked by the Goldsmiths' Hall, because there they would put on the modern marks, and the silversmith, of course, wants only the old marks, which, in this case, would be on the bottom of the salver.
(3). Frequently old tea-pots, jugs, kettles, etc., have modern chasing or engraving on them, but this is permissible and can readily be detected by the expert. It is generally done to please the owner of the article and not to deceive or enhance the value; in fact, the chasing or engraving in many cases renders the piece less valuable in that it alters its antique character. On the other hand, this surface alteration, if done in the style of the period when the piece was made, sometimes increases the value of the article by making it more decorative. A very common form of fraud is to engrave an old piece of silver with the crest and coat-of-arms of some celebrity, often adding an interesting inscription.
When a piece of plate is changed into another article it is called a transformation. This form of forgery is practiced to make an article more desirable, and it is the commonest kind of counterfeiting. Examples of transformations are as follows: Sauce-boats are made into three-legged basins – chiefly Irish ones; wine-funnels into pierced baskets; meatdishes into waiters; dishes, plates or waiters into bowls or baskets; pint mugs into jugs; Queen Anne saucepans into tankards; spoons into forks; skewers into handles of spoons or ladles.
When an article is transformed the marks are not touched; but in changing the form of the piece the marks often become twisted or defaced, and frequently appear in the wrong place, and sometimes upside down. In the chapters describing the different articles, much attention has been paid to the correct positions of the hall-marks on the various pieces.
A fraud is termed a transposition when a genuine mark has been removed from an old piece of silver and inserted into a new article made to resemble an old one, or put into an old piece that has no marks on it, or inserted into an old hall-marked piece after removing the original marks - in the last case the inserted marks are much older than the original. The genuine mark is taken from some small and inexpensive article; for instance, an old spoon-handle with the Dublin marks on it will be inserted into the rim of a modern Irish potato-ring.
In order to insert a mark, solder, in most cases, must be employed, and a cursory examination of the piece would not detect the presence of the solder marks. But if suspicion is aroused, the existence of solder can be discovered in one of the following ways: by using a magnifying glass, by polishing the surface of the silver and breathing on it, by applying sulfur fumes, or by means of the blow-pipe. The solder is sometimes hidden by a little chasing.
* Counterfeit Marks
A counterfeit mark is one that has been stamped by a punch other than that of the Goldsmiths' Company, or it is a genuine mark altered in one way or another. A forged punch is made of the hall-marks of a hundred years ago; this is used to mark modern silver and in that way make it appear old. Another way is to reproduce exactly an old piece of silver, including the old marks, by means of the electrotyping process. When this has been done, an expert can tell it at a glance by the appearance of the silver.
The mark of the Sovereign's head is sometimes removed to make the marks appear older. Another way of altering the marks is to remove an unimportant maker's mark and substitute a much sought after mark, such as that of Paul Lamerie, which advances the price of the article at least £2 ($10) an ounce. Modern articles, made of Britannia Standard, are sometimes sold as Queen Anne's pieces, on account of the resemblance of two of the modern marks to the old ones.
* How to Detect Frauds
Having considered the principal methods of forging plate, the question now presents itself, how can we determine whether a piece of silver is antique or modern? We will answer that question by explaining what an expert does when his suspicions are aroused. He can have a portion of the article assayed to see if it be of the proper standard. He considers the style of the period that the hall-marks call for; frequently the counterfeiter does not pay much attention to this matter. The expert looks carefully at the piece to see how it was made – the ways of manufacturing silver have changed from time to time. The appearance of antique silver is very difficult to imitate, and although it is almost impossible to describe just what this old appearance is like, nevertheless it is quite real to one accustomed to examining plate. While the price of an article of old silver does not necessarily prove its antiquity, nevertheless if one is offered by a dealer an antique much below the current price, it may be an indication that something is wrong. Defects in an article must not be taken as signs of age, for they are very easy to produce. One must be careful that the article does not antedate its introduction; for instance, an expert would not buy an Elizabethan tea-pot, or a four-pronged fork of the time of Henry VIII.
Articles made since the time of Elizabeth, with only a maker's mark, should be avoided, although the unscrupulous dealer will show you in some book of reference that it is the mark of a celebrated silversmith. Such pieces are seldom genuine. The forger escapes penalties by leaving off the hall-mark, as there is no penalty for simply copying the maker's mark. Of course, no such piece could be sold openly in England, for, unless hall-marked, it is liable to conf1scation; but in America, where there are no restrictions, the opportunity for deception is easy, and forged goods are specially made for this market.
Almost every country in Europe has made spurious silver articles, or "duffers," as they are called in the trade. France has perhaps produced the cleverest, Holland the worst, and England the most. America is the last sinner, and in New York City "duffers" are being produced in small quantities. They are very poorly done, and such stupid blunders are made in the hall-marks that it is very easy to detect the counterfeiting.
On account of the unselfish energy of a few prominent silversmiths in London, backed up by the Goldsmiths' Company, some very heavy fines were recently inflicted upon several well-known dealers in forged plate. This put consternation into the camp of counterfeiters, and as a consequence there is a temporary diminution in the supply of spurious old silver.
Fused Plate: Excerpted and edited from Sheffield Plate: Its History, Manufacture and Art by Bertie Wyllie (London, 1908). Sheffield plate [fused plate] is 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 snuffboxes, 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, one to 12 inches in thickness, 21 inches 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, with a thickness up to one inch according to the quality aimed at, and of the same superficial extent as the copper bar, was leveled 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 in. thick was laid upon the silver, and on the top of all was added a piece of iron, four inches thick, one inch 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 molded 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 remedied 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 labor 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 favor with the gold and silversmiths 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 connoisseur, 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 color 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.