This enormous mass of metal was east at once, or in a single getto. The preparation of the model and mould was on the following plan : When the model of the statue was finished, a safe mould of plaster and brickdust was made from it in many parts. [Moosussro.] Each of these parts being marked and numbered, and removed from the model, was then oiled, and carefully filled on the inner side to a certain thick ness, an inch or two, with the modelling-wax already described; the thickness depending upon the height or position of the part, the lowest parts being the thickest, for the metal is destined to fill exactly the space occupied by the wax. When all the parts of the mould were thus prepared, the whole was again put together in a pit, around a simple framework of iron bars, so as to support it firmly in each direc tion ; the lowest parts of the mould being first placed, and the joints )f the wax of the various contiguous parts being filled in, and the pieces carefully united together with melted wax with a brush, as the work proceeded. When the whole was put together, it was bound on :he exterior with strong bars of iron attached to the extremities of the oars of the interior framework. The mould is now a hollow shell, with a thick coating of wax all over the interior, the whole being kept together by iron supports, inside and outside. The next step is to fill his hollow shell, through an aperture left at the top, with a corn iesition of plaster and brickdust, which is fireproof. This fire-proof ody is termed in English a core, by the French noyau, by the Germans ':ern, and by Vasari the anima. Air-vents must be made in the shell lefore the casting of the core.
When the core is fixed, the original mould or shell is taken oft and a wax model of the statue appears to the eye. The sculptor now ex amines his wax model, and improves it where there is occasion and repairs or makes good all imperfections. When it is perfectly finished, the preparation for the founding eommences. Over this wax statue a new fire-proof mould is made of plaster, brickduet or sand, cow hair, and horse-dung, and sometimes very fine ashes. This composition, used at first as a fine liquid plaster, is put on in many coats with a brush, and care must be taken that every particle of wax is covered with the finer plaster: each coat is allowed to dry before the successive coat is put on, and the composition may be gradually made of a coarser mixture. When this new shell or mould is of a sufficient thickness and is properly strengthened by iron bars, a coal fire must be kindled round it and be allowed to burn until the whole of the wax is burnt out, proper vents being made for its escape. This burning out of the wax is a most tedious and difficult process, lasting sometimes as much as four or even six weeks. (Sold, Bildende ICtunst in 34ttuchen,' Stiglinsyer, p. 484.) The great difficulty and long process of molting out the wax was the cause of what is called the wax method going comparatively out of use, but it is only recently that the clay and sand modelling as its substitute has been generally established. Until 1824 Stiglmayer, one of the most successful of recent founders, used the wax method; from that time the clay method. The largest single mat
by Stiglmayer did not amount to one-half of the given weight of this enormous cast by Keller : it is, however, now no longer con sidered desirable to cast a monument in a single gate. [BRONZE; Soutrrone.] When the wax is at length melted out, the mould must be strength ened by brickwork, and the whole pit must be closely filled with sand. A channel is now made from the furnace, and is divided in its course into three entailer channels or duets which lead to three openings in the new hollow mould, which is buried in the earth a little below the furnace. The vacuum in the mould caused by melting out the wax is to be filled with metal ; the original iron framework, which was con structed before the casting of the core, keeps both the core and the mould in their proper places ; and air-vents in various parts of the mould preclude any great probability of accident. When all is ready, the furnace is opened at a given signal, the liquid fire runs in the channels simultaneously into the mould, and that part of the work which was previously soft wax becomes perennial bronze. The cast is accomplished when the metal pours out from the vents. When cool, the mould is broken away piecemeal, and the metal is exposed. The core is then removed from the inside through an aperture made on purpose ; the whole is then repaired and finished by the bronze workers. [Bstosza.1 Johann Balthasar Keller, who cast in this method the statue of Louis XIV., was a Swiss, and originally a goldsmith. Ho was born at Zurich, in 1638, and died at Paris, superintendent of the royal foundry, in 1720. There is a print of the statue by C. Simo neau : it was cast in 1609.
Vasari (Introduzione, L c.) describes a very simple method for casting small figures in bronze. When the mould (cappa) is made, it must be reversed in water ; melted wax is then poured into it, that coming in contact with the cold wet surface of the mould cools' immediately, while the interior portion remains liquid ; the mould must be again turned over, when the still liquid wax in the centre will immediately run out, leaving in the mould a hollow wax shell. The shell must now be filled with the proper plaster, and this constitutes the core of the object. The wax is then burnt out, and the cast is made as usual.
It remains to treat of that department of wax-modelling termed Ocroplastic. Under this term is comprehended modelling and costing In wax, though not in the manner already described. The art of casting in wax from nature was, according to Pliny (' Hist. Nat.' xxxv. 44), invented by Lysistratus, of Sicyon, the brother of Lysippus, about 300 m.o., who, he says, first of all mon took plaster moulds from the face and made wax casts from them. These wax portraits became eventually very common, and especially among the Romans. It is however very unlikely that the many treasured wax portraits we read of in ancient writers were made from moulds taken from the face itself. Such would be the mere resemblance of death, for they would be without eyes and otherwise void of expression. They were probably cast from moulds taken from model, though such masks mey have been used in the formation of the models.