Asiatic Coins

Striking of coins or medals is done by means of dies, engraved in intaglio, and impressed on the metal by blows or pressure. It is the method of impressing a signet on wax applied to a hard material, the type of a coin being, indeed, in origin and principle the signet of the issuing authority. The die had first to be en graved in a hard material. Not until Roman times was iron and occasionally steel used for this purpose. The Greeks used bronze, and analysis of two of the extremely few Greek dies that have survived shows a proportion of from 18 to 22% of tin, the rest being copper with negligible impurities. Such proportions mean a very hard quality of bronze. Modern dies are all of steel.

Hubbing and Cutting.—The die can be cut direct in reverse as an intaglio gem is cut. Or a positive punch or hub can be carved in relief in hard metal, and hammered into a piece of softer metal, which can then be hardened for use as a die. Details which cannot be produced by hubbing in this way can be finished by direct cutting. Both methods were known to the ancients; though no ancient hubs, and very few ancient dies are preserved, exami nation of the struck coins reveals certain details which can only be due to hubbing. The amount of time and labour saved by hubbing is immense ; with one hub many dies can be made, whereas if the design is represented by a die alone, when that breaks or wears out all the work has to be done again. The instruments used in antiquity by die-engravers were the graver or scauper and the dotting-punch. There is no evidence that they used the drill, although that instrument was in the hands of every gem-engraver. The fineness of the work, the almost microscopic detail, must have necessitated the use of magnifying glasses, and there is evidence, literary and material, that these were known to the ancients. (See ENGRAVING.) The Reducing Machine.—The second way of obtaining a die was invented in the 19th century and, greatly to the detriment of the art, ousted the method of cutting by hand. It involves the use of the reducing machine, which dates in origin from about 1839 (see MINT). The artist first makes a model in wax or plaster at least four times the size of the piece to be produced. This, reproduced in a nickel-faced copper electrotype, is placed in the machine, which works on the familiar principle of the pantograph. A tracer at one end of the proportional arm moves over the whole surface of the model. At the other end a cutting point, revolving rapidly, cuts an exact, mathematically reduced reproduction Jf the model. Thus is produced a punch which,

when driven into another piece of soft steel, afterwards hardened, gives the die which can be used to strike the coin or medal. It is obvious that the die so produced is at least three stages removed from the artist's original model which may not be suitable for a small scale relief, however exact.

The result of the introduction of this machine has been that artists have ceased to trouble themselves about the final metallic product. Not having to cut the metal themselves, they have lost the sense of material. They model in wax or plaster, and the coins or medals which are struck from the dies produced without their intervention appear as if they were made of wax or plaster coloured to look like metal.

Preparing the Blanks.

In ancient times dies were cast, sometimes actually in globular form, more usually in a form ap proximating to that of the final product, with sufficient convexity to allow the metal to penetrate to the deepest recesses of the die. They could also he cut from bars. The thin blanks of the middle ages were clipped out of a sheet of metal; in modern times they are punched out of a rolled bar. In antiquity, the lower die, which produced the obverse, was let into an anvil. The upper (for the reverse) was on the end of a cylindrical bar. The blank being placed on the anvil die, the reverse die was placed above it, and a sledge-hammer brought down on the upper end of the bar. How far the blank was heated before being struck we do not know. Such a primitive method of striking, without a collar to keep the blank in shape, produced great irregularities, splitting of the edge, double-striking and the like. The Greeks were indif ferent to such things. The methodical Roman was more careful, and his coins are less irregular in shape. The sledge-hammer blows of course placed great strain on the dies. The first invention to obviate that disadvantage consisted in placing the dies in a frame and hammering wedges in between frame and dies, thus forcing the latter on to the blank between them. In the reign of Julius II. (1503-17) Bramante began experimenting with a press for papal leaden seals; and Leonardo da Vinci also made experiments with a coining press, and more particularly in the process of drawing strips of metal to the right thickness and punching out blanks. Out of such experiments grew the screw-press, the essential ad vantage of which was that the upper die was brought down on the blank not with a blow, but with a gradual pressure.