On the Economy of Machinery and Manufactures eBook

This eBook from the Gutenberg Project consists of approximately 358 pages of information about On the Economy of Machinery and Manufactures.

111.  Casting in wax.  This mode of copying, aided by proper colouring, offers the most successful imitations of many objects of natural history, and gives an air of reality to them which might deceive even the most instructed.  Numerous figures of remarkable persons, having the face and hands formed in wax, have been exhibited at various times; and the resemblances have, in some instances been most striking.  But whoever would see the art of copying in wax carried to the highest perfection, should examine the beautiful collection of fruit at the house of the Horticultural Society; the model of the magnificent flower of the new genus Rafflesia—­the waxen models of the internal parts of the human body which adorn the anatomical gallery of the Jardin des Plantes at Paris, and the Museum at Florence—­or the collection of morbid anatomy at the University of Bologna.  The art of imitation by wax does not usually afford the multitude of copies which flow from many similar operations.  This number is checked by the subsequent stages of the process, which, ceasing to have the character of copying by a tool or pattern, become consequently more expensive.  In each individual production, form alone is given by casting; the colouring must be the work of the pencil, guided by the skill of the artist.

Of copying by moulding

112.  This method of producing multitudes of individuals having an exact resemblance to each other in external shape, is adopted very widely in the arts.  The substances employed are, either naturally or by artificial preparation, in a soft or plastic state; they are then compressed by mechanical force, sometimes assisted by heat, into a mould of the required form.

113.  Of bricks and tiles.  An oblong box of wood fitting upon a bottom fixed to the brickmaker’s bench, is the mould from which every brick is formed.  A portion of the plastic mixture of which the bricks consist is made ready by less skilful hands:  the workman first sprinkles a little sand into the mould, and then throws the clay into it with some force; at the same time rapidly working it with his fingers, so as to make it completely close up to the corners.  He next scrapes off, with a wetted stick, the superfluous clay, and shakes the new-formed brick dexterously out of its mould upon a piece of board, on which it is removed by another workman to the place appointed for drying it.  A very skilful moulder has occasionally, in a long summer’s day, delivered from ten to eleven thousand bricks; but a fair average day’s work is from five to six thousand.  Tiles of various kinds and forms are made of finer materials, but by the same system of moulding.  Among the ruins of the city of Gour, the ancient capital of Bengal, bricks are found having projecting ornaments in high relief:  these appear to have been formed in a mould, and subsequently glazed with a coloured glaze.  In Germany, also, brickwork has been executed with various ornaments.  The cornice of the church of St Stephano, at Berlin, is made of large blocks of brick moulded into the form required by the architect.  At the establishment of Messrs Cubitt, in Gray’s Inn Lane, vases, cornices, and highly ornamented capitals of columns are thus formed which rival stone itself in elasticity, hardness, and durability.

Project Gutenberg
On the Economy of Machinery and Manufactures from Project Gutenberg. Public domain.
Follow Us on Facebook