Scientific Notices. Red color for paper-hangings, &c.

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

It is proposed to employ the red chloride of chrome for the production of an intense red violet color, possessing metallic lustre, proper for printing or staining paper.

This product is prepared, as is well known, by passing a current of dry chlorine gas over a mixture of powdered charcoal and calcined oxide of chrome, enclosed in a glass tube. Attention must be especially given in this operation to the fact that, by reason of the difficulty of volatilization of the product, the chloride prepared by a first operation remains mixed with the powdered charcoal. It is, therefore, requisite to submit this mixture of charcoal and chloride of chrome to a second operation, taking care to cover the bottom only of the glass tube with it,—in which case the product will be sublimed in the upper part of the tube. The heat of an argand lamp, the flame of which is brought gradually upon the tube, will suffice for the formation of the chloride, which soon appears in the form of brilliant micaceous peach-colored spangles. The chloride is then ground in a mortar, and thickened with a mucilage of gum. On being laid upon paper it will display its original color, and will resist the action not only of acids and alkalies, but also the direct action of the solar rays.

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