is the art of working metals by pouring them while in a fluid condition into moulds where they solidify and harden into the form of the mould they fill. It is the most important of the operations by which metals are fashioned into ornamental and useful forms, although in practice some metals cannot be cast. It is an art that has been known and practised from very early times. In the Victoria and Albert Museum there is some cast bronze coinage belonging to the Chou dynasty dated 1122-1225 B.C. In the room of Greek and Roman life at the British Museum there is a limestone mould for casting metal which was in use about the eighth century, B.C., a bronze mould for palstaves (a kind of axe), and a stone mould for casting hammer heads. This last is illustrated in Ch. xiv, f. 4. Nos. 8 and 9 on the same page are bronze castings of an early date.

There are many operations in casting, and the article to be produced is now seldom made, moulded, and cast by one man, as was the case when Ben-venuto Cellini modelled his figure of Perseus, and directed and helped in the casting of it. The most important operations in casting are making the pattern, making a mould from this in sand or some other suitable material, and melting and pouring the metal into the mould. Patterns are usually made outside the foundry or in the patternmaker's shop, quite distinct from the foundry. It is a woodworking trade, and the pattern-maker should have a knowledge of metals and of foundry practice. Iron is practically always cast in an iron foundry, while all the non-ferrous metals and alloys are cast in what is called a brass foundry. The tendency of the times is to specialize in one particular metal or group of metals, and by so doing better castings at a cheaper rate are obtained. Patterns are made either in metal, wood, plaster of Paris, or wax. Patterns which must be hollow have cores made of sand and shaped in core boxes. Moulds for casting metal are made of sand, metal, or a mixture of plaster of Paris and brick dust. When sand is used it is contained in an iron frame called a flask; this flask consists of two iron frames which fit together with pegs and eyes, the pegs on one frame the eyes on the other. There is green-sand moulding which is moulding in sand that is not dried, and dried sand moulding, where the mould has to be dried or baked in an oven. Large iron castings are cast in a loam mould, which is often made by being "swept up". When the object is circular a piece of flat wood made to the shape required and pivoted on a centre rod and revolved against a mass of sand cuts or"sweeps up"the mould. Cores are also made by sweeping up.

When the surface of an iron casting is wanted extremely hard, as in the case of car wheels, or rolls, this part of the mould is made of iron, so that when the molten metal flows against the cold iron it is chilled and hardened. Sand, owing to its cheapness, porosity, and refractoriness, is the best and most convenient material for moulding. Its porosity allows for the escape of the gases generated, while its refractoriness keeps it in shape when the molten metal is poured into the mould. The best moulding sand is found along the banks of large rivers. For repetition work moulding machines worked by hydraulic power or by hand have displaced hand moulding and are now largely used.

Another method of casting, known as "Cire Perdu" or the lost wax process, is used for the best class of figure work, not the bronze figures one sees sold with clocks and marked at £2 17s. 6d. the set. These are mostly cast of zinc or antimonial lead, in what is known as a slush mould. A good illustration of the lost wax process is shown in the Indian section of the Victoria and Albert Museum. It is a sand mould containing a cast brass curb chain anklet; a model of the anklet is first made in wax, each link being unconnected with the others except by a narrow band along the top. The model is gradually encased with the liquid composition which forms the mould; the metal is deposited in a crucible attached to the mould and the whole is placed in the fire. The action of the fire destroys the wax model, the wax being absorbed into the mould, which then retains a complete impression of the anklet, each link being separate from the other with the exception of the narrow band at the top. When the metal is ready the whole affair is reversed, the hot metal fills the impression left by the wax model, and when the band connecting the links is filed off the anklet is left in the form of a chain. This object is from Rajputana. The candlestick on p. 94 is an example of cast and turned work, and the method of making it is shown on the page following.

Castings and wood patterns showing how the patterns would be made for various objects are illustrated in Chs. vii and ix.

The Dutch chandelier (Ch. xii, f. 8) is a good example of cast and turned work. The handles (Ch. v, f. 6, Nos. 10, 11, 12) would have to be modelled in wax and then cast in plaster, or carved in wood. It would be better to have these cast in"fine cored brass,that is, the mould would have to be faced with some very fine parting compound such as French chalk, which gives a fine outer surface to the finished casting, and cored. It is cored by having small pieces of moulding sand fitted to the various undercut parts so that they will come away and the pattern be withdrawn and then the pieces of sand called"false cores "are replaced so that the mould is perfect and ready for receiving the metal. The majority of patterns received by founders from artists are in plaster, and off these plaster patterns piece moulds are made in sand.

The metal used in an iron foundry is usually melted in a cupola furnace, but other metals than iron are melted in crucibles which are placed inside a furnace heated by gas, coke, or oil. Modern furnaces are mostly heated by gas or oil, and can be tilted so that the metal may be poured into the ladle or mould direct, thus saving the trouble of lifting the crucible full of molten metal out of the fire by manual labour. Crucibles are made of plumbago, graphite, fire clay, etc. The plumbago crucible consists of equal parts of clay and graphite. Owing to the great differences in characteristics and faults which are inherent in the metals themselves, a knowledge of metallurgy is very necessary for the successful casting of metals. The most common faults in castings are:-

Blow Holes, caused by the gases not getting away.

Overshot Castings, caused by badly fitting flasks.

Oval Castings instead of round, owing to the moulds being pinched together too lightly.

Seared Castings, caused by the mould being too hard and not allowing the metal to shrink.

Imperfect Corners, owing to the metal being poured at too low a temperature or the corners of the mould not being pricked to allow the metal to run up sharp.

For the shrinkage of metals in castings see pp. 127-128.