The article must first be well cleaned, and ' pickled' in dilute acid. Then dissolve sulphate of copper, 2 oz., in boiling rain-water; when cold add carbonate of potash, 4 oz., and liquid ammonia 2 oz. A precipitate forms, which is redissolved. Add cyanide of potassium (6 oz.) until all the 'blue colour disappears. Make up to 1 gallon, and work with a two-cell battery. The surface obtained may be bronzed. (See back, Bronzing Liquids.)
See Gilding, further on.
See Silvering, further on.
Elastic. [For copying medals when the figures are in high relief] To 12 parts of carefully melted glue, add 3 parts of treacle, and incorporate them perfectly. Gutta Percha Moulds are made by softening a piece of gutta-percha by warm water (150° to 160°) and pressing the metal into it by a screw. See Solutions.
Put the engraving on a smooth board, and cover it thinly with common salt, finely powdered; pour and squeeze lemon-juice upon this salt, so as to dissolve a considerable portion of it. Now elevate one end of the board, that it may form an angle of about 45° with the horizon. Pour lastly on the engraving, boiling water from a tea-kettle, until the salt and lemon-juice are all washed off; the engraving will then appear perfectly clean, and free from stains. It must be dried gradually, on the same board, or on some smooth surface. - Francis.
Sulphate of copper 1 oz., sal ammoniac 1/2 oz. Pulverize separately, adding a little vermillion to colour it, and mix with 1 1/2 oz. of vinegar. Rub the steel with soft soap, and write with a clean hard pen, without a slit, dipped in the mixture.
Acetate of amylene is sold under this name. It is made by distilling a mixture of 1 part of oil of grain, 2 of acetate of potash, and 1 of oil of vitriol. Wash the diluted liquid with alkaline water, agitate with dry chloride of calcium, and redistil it from litharge.
See Butyric Ether.
[For Perfumed Essences, see Perfumery, For Culinary Essences, see further back.]
For Lithography. Dissolve 3 oz. of fused chloride of calcium in 9 1/2 oz. of water, add to the solution 2 oz. of gum arabic, and 1 oz of pure hydrochloric acid. - Chevallier.
1. Aqua fortis 2 oz., water 5 oz.; mix.
3. Callot's Fau Forte, for Fine Touches. Dissolve 4 parts each of verdigris, alum, sea-salt, and sal ammoniac, in 8 parts of vinegar; add 16 parts of water, boil for a minute, and let it cool.
1. Iodine 1 oz., iron filings 1/2 drachm, water 4 oz.; digest till the iron is dissolved.
3. Mix 10 parts of pure hydrochloric acid, 70 of distilled water, and a solution of 2 parts of chlorate of potash in 20 of water. Dilute before using with from 100 to 200 parts of water. See Engravings, Photographic.