Assaying is the estimation of the amount of pure metal, and especially of the precious metals, in an ore or alloy. In the case of silver the assay is either by the dry or by the wet process. The dry process is called eupellation from the use of a small and very porous cup, called a cupel, which is usually made of well-burned and finely-ground bone-ash or of magnesia. The cupel, being thoroughly dried, is placed in a fire-clay oven about the size of a drain-tile, with a flat sole and arched roof, and with slits at the sides to admit air. This oven, called a muffle, is set in a furnace, and when it is at a red heat the assay, consisting of a small weighed portion of the alloy wrapped in sheet-lead, is laid upon the cupel. The heat causes the lead to volatilize or combine with the other metals, and to sink with them into the cupel, leaving a bright globule of pure metallic silver, which gives the amount of silver in the alloy operated on. In the wet process the alloy is dissolved in nitric acid, and to the solution are added measured quantities of a solution of common salt of known strength, which precipitates chloride of silver. The operation is concluded when no further precipitate is obtained on the addition of the salt solution, and the quantity of silver is calculated from the amount of salt solution used.
An alloy of gold is first cupelled with lead as above, with the addition of three parts of silver for every one of gold. After the cupellation is finished the alloy of gold and silver is beaten and rolled out into a thin plate, which is curled up by the fingers into a little spiral or cornet. This is put into a flask with nitric acid, which dissolves away the silver and leaves the cornet dark and brittle. After washing with water the cornet is boiled with stronger nitric acid to remove the last traces of silver, well washed, and then allowed to drop into a small crucible, in which it is heated, and then it is weighed. The assay of gold, therefore, consists of two parts: cupellation, by which inferior metals (except silver) are removed; and quartation, by which the added silver and any silver originally present are got rid of. The quantity of silver added has to be regulated to about three times that of the gold. If it be more the cornet breaks up, if it be less the gold protects small quantities of the silver from the action of the acid. Where, as in some gold manufactured articles, these methods of assay cannot be applied, a streak is drawn With the article upon a touchstone consisting of coarse-grained Lydian quartz saturated with bituminous matter, or of black basalt. The practised assayer will detect approximately the richness of the gold from the colour of the streak, which may be further subjected to an acid test. The Goldsmith's Company of London is the statutory assay-master of all England. Research Assaying
A bell is a hollow, somewhat cup-shaped, sounding instrument of metal. The metal from which bells are usually made (by founding) is an alloy, called bell-metal, commonly composed of eighty parts of copper and twenty of tin. The proportion of tin varies, however, from one-third to one-fifth of the weight of the copper, according to the sound required, the size of the bell, and the impulse to be given. The clearness and richness of the tone depend upon the metal used, the perfection of its casting, and also upon its shape; it having been shown by a number of experiments that the well-known shape with a thick lip is the best adapted to give a perfect sound. The depth of the tone of a bell increases in proportion to its size.
A bell is divided into the body or barrel, the ear or cannon, and the clapper or tongue. The lip or sound-bow is that part where the bell is struck by the clapper. It is uncertain whether the jangling instruments used by the Egyptians and Israelites can be correctly described as bells; but it is certain that bells of a considerable size were in early use in China and Japan, and that the Greeks and Romans used them for various purposes. They are said to have been first introduced into Christian churches about 400 AD by Paulinus, bishop of Nola, in Campania (whence campana and nola as old names of bells); although their adoption on a wide scale does not become apparent until after the year 550, when they were introduced into France.
Benedict Biscop, abbot of Wearmouth, seems to have imported bells from Italy to England in 680, but their use in Ireland and Scotland is probably of earlier date. The oldest of those existing in Great Britain and Ireland, such as the 'bell of St. Patrick's will' and St Ninian's bell, are quadrangular and made of thin iron plates hammered and riveted together.
Until the thirteenth century bells were of comparatively small size, but after the casting of the Jacqueline of Paris (6.5 tons) in 1400 their weight rapidly increased. Among the more famous bells are the bell of Cologne, 11. tons, 1448; of Dantzic, 6 tons, 1453; of Halberstadt, 7.5, 1457; of Rouen, 16, 1501; of Breslau, 11, 1507; of Lucerne, 71, 1636; of Oxford,7.5 1680; of Paris, 12.8, 1680; of Bruges, 10.5, 1680; of Vienna, 17.75, 1711; of Moscow (the monarch of all bells), 193, 1736; three other bells at Moscow ranging from 16 to 31 tons, and a fourth of 80 tons cast in 1819; the bell of Lincoln (Great Tom), 5.5, 1834; of YorkMinster (Great Peter), 10.75, 1845; of Montreal, 134, 1847; of Westminster (Big Ben), 15.5, 1856, (St Stephen), 13.5, 1858; the Great Bell of St. Paul's, 17.5, 1882. Others are the bells of Ghent (5 tons), Gorlitz (10.75 tons), St Peter's, Rome (8 tons), Antwerp (7.25 tons), Olmutz (18 tons), Sacred Heart, Paris (27 tons), Novgorod (31 tons), Pekin (53.5 tons).
Besides their use in churches bells are employed for various purposes, formerly the most common use being to summon attendants or domestics in private houses, hotels, etc. Bells for this purpose were of small size and may be held in the hand and rung, but most commonly were rung by means of wires stretched from the various apartments to the place where the bells were hung. Bells rung by electricity became common in hotels and other establishments around 1905.
The coconut cup was a drinking vessel first seen in Britain around the 13th century, and used by the rich who preferred them to the more 'common' mazer-bowl. Coconut cups were made from a coconut shell, mounted on a Gothicsilvermount and mounted with silver at the rim. Similar vessels were also made from ostrich eggs (then called griffin's eggs). Research Coconut Cup
Enamel is a vitreous glaze of various colours fused to the surface of gold, silver, copper, and other substances. The art of enamelling, which is of great antiquity, was practised by the Assyrians and by the Egyptians, from whom it may have passed into Greece, and thence into Rome and its provinces, including Great Britain, where various Roman antiquities with enamelled ornamentation have been discovered. The enamelled gold cup given by King John to the corporation of Lynn, in Norfolk, proves that the art was known among the Normans. The Byzantines of the 10th century produced excellent cloisonne enamels on a gold base, the cloisonne process consisting in tracing the design in fillets of gold upon the gold plate and filling up the small moulds thus formed with enamels the design appearing in coloured enamels separated by thin gold partitions or cloisons. In some cases, however, the enamels were filled into hollows beaten out in the gold plate, which formed part of the field.
In the 12th century the town of Limoges acquired the high reputation for inlaid enamels which it held until the 14th century, aud re-acquired in the 16th for its painted enamels. The costliness of the sculptured ground had led the Italians early in the 14th century to substitute the practice of incising the design on the face of the plate, and then covering it with a transparent enamel. The further step, which made the Limousin workshops famous, consisted in the method of superficial enamelling, in which opaque colours or colours laid on a white opaque ground were used. The Limoges school degenerated greatly in the 17th century, but its method with certain modifications in detail is still employed.
The basis of all kinds of enamel is a perfectly transparent and fusibleglass, which is rendered either semitransparent or opaque by the admixture of metallic oxides. White enamels are composed by melting the oxide of tin with glass, and adding a small quantity of manganese or phosphate of calcium to increase the brilliancy of the colour. The addition of the oxide of lead, or antimony, or oxide of silver, produces a yellow enamel. Reds are formed by copper, and by an intermixture of the oxides of gold and iron. Greens, violets, and blues are formed from the oxides of copper, cobalt, and iron.
In the middle of the 18th century enamelling was largely applied to the decoration of snuff-boxes, tea-canisters, candlesticks, and other small articles. Of later years it was extensively applied to the coating of iron vessels for domestic purposes, the protection of the insides of baths, cisterns, and boilers, and the like. Enamelling in colours upon iron was common, iron plates being thus treated by means of various mixtures, and words and designs of various kinds being permanently fixed upon them by stencilling, for advertising, signboards, etc.
In Judaism, Kiddush is a prayer recited on the Sabbath, at festivals, and the New Year, acknowledging the sanctity of the holy day and concluding with the formula, 'Praised be Thou, O Lord, who sanctifies the Sabbath, ' or 'who sanctifies Israel and the festivals.' Before a festive meal on the eve of the Sabbath or holiday, the Kiddush is recited over a cup of wine by the head of the household. It includes the customary blessing over the wine and is accompanied by biblical verses. The wine benediction and biblical verses are also recited before the large first meal on the morning of the Sabbath or festival. No food can be eaten before the Kiddush is recited. It is also traditional to recite the Kiddush in the synagogue at the conclusion of the evening and morning services. This custom originally was instituted for the benefit of travellers who might be lodging and eating at the synagogue over the Sabbath or festival. Research Kiddush
Mazer-bowls, also known simply as a mazer or a mazer cup, we drinking vessels first introduced to Britain in the 14th century. They were a bowl made of spotted maple wood, whence their name, and normally mounted in latten metal, silver or silver-gilt, with a wide band around the rim. Often a circular medallion was mounted in the bottom of the bowl, and the whole was finished by a foot or set upon a baluster. By the end of the 16th century were the most popular drinking vessels in Britain. Research Mazer-Bowl
Originally a noggin was a small cup or mug developed during the mid-17th century. By the end of the 17th century the term was applied to a measure (usually a quarter of a pint, the size of a noggin vessel) of alcoholic liquor. Research Noggin
An oenocho was an ancient Greek jug with a curved handle extending from the lip to the shoulder used for ladling wine from a bowl into a cup. Research Oenocho
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Assaying
