Scientific Intelligence. — Arts. B99 



three times on the palette, near one extremity, by which a small 

 portion of the lead is sifted, as it were, through the muslin ; the 

 brush is passed round in the pulverised graphite, and on some 

 other part of the palette, to adjust the shade required ; the 

 brush is then applied to the paper, to produce a sky, or other 

 expanse of shade, with a circulating motion. To produce a 

 darker shade, the graphite may be rubbed in with alder, pith, 

 or any similar substance, brought to a point. — GilPs Technical 

 Repository/, 1827. 



11. Oji Etching and Dyeing at once figures on I-oory ; by 

 Mr J. Cathery, — The usual mode of ornamenting ivory in black, 

 is to engrave the pattern or design, and then to fill up the cavi- 

 ties thus produced with hard black varnish. The demand for 

 engraved ivory in ornamented inlaying, and for other purposes, 

 is considerable, although the price paid for it is not such as to 

 encourage artists of much ability to devote themselves to this 

 work, which consequently is trivial in design, and coarse in exe- 

 cution. IVIr Cathery's improvement consists in covering the 

 ivory with engraver's varnish, and drawing the design with an 

 etching needle. He then pours on a menstruum composed of 

 120 grains of fine silver, dissolved in one ounce measure of ni- 

 tric acid, and then diluted with one quart of pure distilled wa- 

 ter. After half an hour, more or less, according to the required 

 depth of tint, the liquor is to be poured off, and the surface is 

 to be washed with distilled water, and dried with blotting pa- 

 per ; it is then to be exposed to the light for an hour, after 

 which the varnish may be removed by means of oil of turpen- 

 tine. The design will now appear impressed on the ivory, and 

 of a black or blackish-brown colour, which will come to its full 

 tint after exposure for a day or two to the light. The proper- 

 ty which nitrate of silver possesses, of giving a permanent dark 

 stain to ivory, and many other substances, has been long known ; 

 but Mr Cathery has the merit of having advantageously applied 

 it in a department of art in which it is likely to be of considera^- 

 ble service, by improving the quality of the ornament, and at the 

 same time of diminishing the cost. Varieties of colour may also 

 be given, by substituting the salts of gold, platina, copper, &c. 

 for the solution of silver. — GiWs Repository, Feb. 1827. 



