Scientific Notices. On a new method of Gilding Porcelain.

The London Journal of Arts, Sciences, and Manufactures, and Repertory of Patent Inventions.

Conducted by Mr. W. Newton, of the Office for Patents, Chancery Lane. (Assisted by several Scientific Gentlemen.)

VOL. XXXVI. (Conjoined Series.)

London: Published by W. Newton, at the office for patents, 66, Chancerylane, and Manchester; t. and W. Piper, Paternoster Row; Simpkin, Marshall, and Co., Stationers' Court; J. McCombe, Buchanan St., Glasgow; and Galinani's Library, Rue Vivienne,

Paris. 1850

By M. Grenon.

M. Grenon, decorator of porcelain, of Rue de Faubourg, St. Martin, Paris, submitted to the Society for the Encouragement of National Industry, Paris, an improvement in gilding porcelain, which adds much to its durability.

The operation of gilding, as generally practised, consists, as is well known, in mixing with the preparation of gold and protonitrate of mercury, a certain quantity of subnitrate of bismuth which serves as a flux, and allows the metal to be burnt into the porcelain. The gold prepared by nitrate of mercury, may be applied in extremely thin layers, so that this process will be very economical; it is, however, not very durable. Gold, obtained by sulphate of protoxide of iron, furnishes a more solid, although less economic gilding. Different processes have been employed for rendering gilding more durable without increasing the expense.

M. Rousseau's method is, first to lay a coating of platina, mixed with flux, and then a thin coating of gold upon the platina. This gives a solid gilding, but it is apt to lose its lustre by use,— the color of the gold being modified by that of the platina, which appears when the gold wears away.

M. Grenon's process consists in the successive application of two layers of gold, each having a special flux, and in different proportions. The first layer is first burnt in at a high tempera ture; after which, it is polished with rotten-stone, and on it is laid a thin coating of mercury-gold, which is prepared and burnt in the ordinary manner. This gilding is easily burnished, and takes a fine polish; and it has been proved that friction from hard bodies, which would seriously injure ordinary gilding, does not affect it.

M. Grenon's method merits attention from the public on account of its solidity and brilliancy; the increase in price (which is not very considerable) being justified by the quantity of gold employed, and the double expenses of laying-on and burning.

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