Electro-coppering, for Iron or Zinc

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.

Electrotype Moulds

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.

Process for Cleaning Engravings

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.

Engraving mixture, for Writing on Steel

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.

Essence of Jargonelle Pear

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.

Essence of Pine Apple

See Butyric Ether.

[For Perfumed Essences, see Perfumery, For Culinary Essences, see further back.]

Etching Fluids

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.

For Copper

1. Aqua fortis 2 oz., water 5 oz.; mix.

2. Iodine 2 parts, iodide of potassium 5 parts, water 5 to 8 parts.

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.

For Steel

1. Iodine 1 oz., iron filings 1/2 drachm, water 4 oz.; digest till the iron is dissolved.

2. Pyroligneous acid 4 parts by measure, alcohol 1 part; mix, and add 1 part of double aqua fortis (sp. gr. 1.28). Apply it from 1 1/2 to fifteen minutes.

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.