Oldalképek
PDF
ePub

Before describing the actual coining, the all-important dies must be noticed. The die and medal department at the Mint contains many such dies in various stages of progress, and coins and medals which have been produced by such of them as are finished. Some of the larger medals are of exquisite workmanship, and have called forth the highest abilities of our Wyons and Pistruccis. Confining ourselves, however, to coins, a punch is engraved for each kind of coin, by patient cutting, with very hard and sharp tools, on a piece of pure steel in a softened state: the design being in relief, as in a finished coin. From this punch the die is produced. The punch is hardened, another piece of steel is softened, and intense pressure is employed to bring about this action of the one on the other. The piece of soft steel becomes a die, on which the device or design is in intaglio, or sunk below the general surface. By repeated careful hardening, each punch can produce a large number of dies. Every die must have a companion or counter-die, to stamp the other surface of the coin; this is obtained by pressure from a separately engraved punch.

The blanks and the dies being ready, the real process of coining ensues. The counter-die is adjusted, face uppermost, in a small frame on the bed of the stamping-press; the blanks are laid one by one on it; and the die is fixed, face downwards, to the bottom of a descending arm. The arm, brought down with great force by the action of a lever and flywheel, subjects the blank to a powerful squeezing, which impresses the device of the die on one surface and that of the counter-die on the other. The metal of the blank would be squeezed out laterally, were it not confined within a steel collar just large enough to fit it. The inside of this collar is milled, or cut into little grooves, the pressure of which produces the milled edge of the coin. All our modern coins have milled edges except the three-penny piece, which has a smooth edge. The blanks are supplied to the press by feeding them into a hopper or tube, pushing them laterally one by one by means of a slide, so as to bring them precisely on the counter-die, and sliding them off when coined.

The sovereign weighing machine, invented by Mr. William Cotton (at one time Governor of the Bank of England), and improved by later inventors, is one of the most beautiful of automatic appliances. The sovereigns are fed into a tube, from which they fall one by one on a small poised plate. If of proper weight, each coin is jerked off into a particular box or compartment; if a little over weight, into a second; and if a little under

weight, into a third. The machine almost thinks while it works, so well does it estimate the real weight of each coin. The degree of accuracy attained in our actual coining is almost marvellous. Supposing the exact proper weight to be represented by 1,000, anything between 998 and 1,002 is allowed to pass; but a coin below 998 is pronounced to be too light, while one exceeding 1002 is subjected to a verdict of too heavy. Besides this individual weighing of gold coins, gold and silver coins generally are weighed in small parcels, and then in larger parcels, in a balance so delicate that it will turn with a single grain even when each scale-pan contains 1,200 ounces.

One of the results of the numerous processes carried on at the Mint is the production of sweep. Besides a very careful treatment of floor-dust, flue-soot, and crucible-scrapings, the worn-out crucibles themselves are made to render up any gold and silver they may contain ingrained in their substance; they are ground to powder, sifted through a sieve having four hundred meshes to the square inch, and handed over to the refiner, who extracts every particle of precious metal. The Mint used to sell the waste and sweep by tender; but it is now found more profitable to employ a refiner and pay him directly for his services. Even old furnace fire-bricks are included in the sweep.

The curious ordeal known as the Trial of the Pyx has, like most other parts of the Mint system, undergone changes within the last few years. Under the plan of contract it was of considerable importance, seeing that the contractors were not entitled to full payment until a jury of experts had delivered a favourable verdict. The trials of the pyx have at different times between 1611 and 1879 been presided over by the monarch, the Lord Keeper, the Lord Chancellor, the Lord President of the Council, and the Archbishop of Canterbury. There were eighteen such trials in the fifty years ending with 1866, rather more than three years' interval on an average. Mr. Chisholm, Chief Clerk of the Exchequer (now Warden of the Standards) was directed in the last-named year to report whether (as was asserted by some members of Parliament) the trial of the pyx was an "idle ceremony" and empty show," or a really useful and necessary operation. He reported decidedly in the latter sense, and, moreover, recommended that the trials should take place annually.

66

The pyx is a box to contain the gold coins that are to be tested, and there is another pyx for silver coins. A few coins from every day's mintage are put into the pyx, and these are taken to

be a fair average of the whole number. Trial plates are preserved with great care, rigorously made of the exact alloy for sterling or standard; and by these the coins are tested. There are trial plates still preserved extending over a period of four centuries, showing in what way the standard has varied from time to time. The present plates, made by the Goldsmiths' Company, are replicated, one copy being kept at the Mint, another at the Assay Office, a third at the Exchequer, a fourth at Goldsmiths' Hall, and others at the official assay offices; but those at Westminster are deemed to be the authoritative standards, brought forward at the trial of the pyx. The boxes and chests containing the trial pieces are secured with the best locks that Chubb can provide, and the keys are so many that the all-important trial-pieces cannot be brought forward to the light of day without a good deal of unlocking by officials. The trial plates were in 1870 transferred from the custody of the Exchequer to that of the Warden of the Standards, an officer under the Board of Trade. He also keeps the Imperial standard weights for weighing gold and silver coins.

The trial of the pyx has been shorn of some of its dignity recently; but the following was, in a general way, the mode of procedure before the trials were made annual. All new coins, as minted, were made up into bags or journeys of 180 oz. gold or 720 oz. silver; a journey being a technical name for coins made in any one day. All the coins in each bag were of one denomination only. One coin was taken from each bag, and put into the gold or silver pyx, as the case might be. One coin out of each bag was also handed to the Queen's Assay Master. The pyxes were locked by three officials, after each day's proceedings. When there were about a hundred bags in each pyx, one pound troy was taken from each, to be counted as well as weighed. Then two coins were taken from each pound by the Deputy Master, and weighed with scrupulous accuracy, any deviation from the proper weight being recorded to a minute fraction of a grain. One of these two coins was sent to the Mint assay room, while the other was placed in the all-important official pyx. On an appointed day the Government, at the instance of the Master of the Mint, invited the Goldsmiths' Company to assist at a trial of the pyx. Many officials assembled at the office of the Queen's Remembrancer, Old Palace Yard; the Pyx Chamber, in the cloisters of Westminster Abbey, was opened, and two trial pieces (gold and silver) taken out; Imperial standard weights of gold and silver were also produced. A jury of goldsmiths, after being

sworn, were at work for several hours, melting into an ingot a certain number of gold coins from the one pyx and of silver coins from the other, rigorously assaying the ingots, assaying small bits of the two trial pieces, and comparing the assays one with another. For convenience, most of these operations were conducted at Goldsmiths' Hall, where the necessary assay furnaces, balances, &c., were ready at hand. At a certain hour in the evening, the jury of goldsmiths having announced that their labours were finished, all the officials again assembled, and the foreman of the jury read their verdict. It is invariably the case that the coins in the pyxes are found to be up to the proper standard, both in quality and in weight, within that minute allowance called the remedy. The Queen's Remembrancer, therefore, pronounced a verdict of acquittal, implying that the Master of the Mint had duly fulfilled his engagement to Her Majesty the Queen. The proceedings of the day were wound up with a banquet given by the Goldsmiths' Company to the officials and persons concerned.

We may remark that, at the trial of the pyx in 1878, the jury comprised ten practical goldsmiths, well versed in the delicate manipulations of their craft. They reported that, out of the bags of coin in the Mint pyxes, 26 sovereigns, 56 halfsovereigns, 10 half-crowns, 9 florins, 6 shillings, 8 sixpences, and 9 threepences (there were no fourpences coined it that year), were taken. They weighed all the coins individually, to a minute fraction; they melted the gold coins into one ingot and the silver into another; they assayed these ingots, and compared them with the gold and silver trial pieces; they weighed and assayed, over and over again, and found that, in all cases, both weight and fineness were far within the remedy. In short, a more complete verdict in favour of the Master of the Mint there could hardly have been.

The remedy, of which we have more than once spoken, is a necessary allowance for human fallibility, like the "personal equation" which is recognized by practical astronomers. By no possible means could perfect accuracy be obtained; an allowance for inaccuracy is necessary; and it is for the parties concerned to decide where the limit should be placed. We have purposely avoided troubling the reader with long rows of decimal fractions, but a few facts may be given to show how well the Mint does its work. At the trial in 1878, five sovereigns, selected at random, ranged between 123 174 and 123 304 grains respectively, and

four half-sovereigns between 61.567 and 61 637 grains. The fineness or standard of the nine coins ranged from 916'5 to 916-8 of pure gold in every thousand parts. Silver coins were, in like manner, tested, and all, of both metals, found well within the remedy, as we have said.

If we estimate the value of an establishment by the amount of work done, it becomes interesting to know how many coins are struck at the Mint, which is strictly a money manufactory. As the amount of coinage is much more in some years than others, and very unequal in the relative numbers of each kind coined, it will be best to take ten consecutive years, from which the reader can easily deduce the average for each year. The following figures refer to the ten years 1869 to 1878 inclusive :—

[merged small][ocr errors][merged small][merged small][ocr errors][merged small][merged small][ocr errors][ocr errors][merged small][merged small][merged small][ocr errors][ocr errors][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][ocr errors][ocr errors][ocr errors][ocr errors][merged small][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][ocr errors][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small][merged small]

The total value of all the coins struck-gold, silver, and bronze

« ElőzőTovább »