Colours for Confctioners

Many fatal accidents occur from confectionery being coloured with poisonous pigments. The following may be safely used: Cochineal and its preparations, sap green, vegetable lakes, Prussian blue; a mixture of a yellow lake and Prussian blue for green.

Colouring for Brandt, etc

Sugar melted in a ladle till it is brown, and then dissolved in water or lime-water.

Colours for Liqueurs

Pink is given by cochineal; yellow by saffron or safflower; violet by litmus; blue, by sulphate of indigo, saturated with chalk; green, by the last with tincture of saffron, or by sap green.

Colours for Leather

See Bookbinder's stains, further back.

Improved Vehicles for Colours

1. One measure of saturated solution of borax, with 4 of linseed oil. The pigment may be ground with the oil, or the mixture.

2. A solution of shell-lac with borax, as in making Coathupe's Writing Fluid. See Ink.

3. Water colours, mixed with gelatine, and afterwards fixed by washing with a solution of alum.

4. Curd of milk, washed and pressed, then dried on fine net, and when required for use, mixed with water and the colouring matter.

Condy's Fluid

(Patent.) The green fluid appears to contain the manganates, the red fluid the permanganates, of soda and potash. The latter is said to be double the strength of the Liquor PotasAe Permanganatis, B. P. Condy's "Ozonized Water" is a weaker solution of the permanganates, "for toilet purposes."

Oxide of Copper

The black oxide is made by calining the nitrate; or by adding caustic potash to sulphate of copper, in solution, and washing and drying the precipitate. The red oxide may be made as directed for Bronze Powder, No. 4, or in the moist way, thus: Pour a solution of 27 parts of sugar in 60 of water, over 9 parts of hydrated oxide of copper, weighed in its compressed but still moist state. A solution of 18 parts of caustic potash in 60 of water is added, and the whole agitated together without heat, and filtered. The clear liquid heated in a warm bath, and continually stirred, deposits the red oxide, and the liquid becomes colourless.

Nitrate of Copper

Dissolve copper in nitric acid to saturation, evaporate to dryness, redissolve, filter, and evaporate, so that the salt may crystallize. Or add a solution of sulphate of copper to a solution of nitrate of lead, so long as sulphate of lead is precipitated; filter, evaporate, and crystallize. For the other salts of copper, see Cuprum, Pocket Formulary.

Cosmolin

See Vaselin, further on.

Cotton Powder

See Gun Cotton.

Crayons for Writing on Glass

Fuse in a cup 4 parts of spermaceti, 3 of tallow, and 2 of wax; stir in 6 parts of minium, and 1 of potash; keep warm for half an hour, and then pour into glass tubes of the thickness of a lead pencil. If cooled rapidly, the mass may be screwed up and down in the tube, and cut at the end to a fine point. The glass to be written on must be clean and dry.

Cyanide of Potassium

See Pocket Formulary.

Depilatories

See Hair Cosmetics, further back.

Dextrin, or Starch Gum

Heat 4 gallons of water in a water-bath to between 77° and 86° Fahrenheit; stir in 1 1/2 or 2 lbs. finely ground malt; raise the temperature to 140°, add 10 lbs. of potato or other starch: mix all thoroughly, raise the heat to 158°, and keep it between that and 167°, for 20 or 30 minutes. When the liquor becomes thin, instantly raise the heat to the boiling point, to prevent the formation of sugar. Strain the liquor, and evaporate it to dryness, as the dextrin will not keep long in a liquid form. Another method is to boil solution of starch with a few drops of sulphuric acid, to filter the solution, and to add alcohol to throw down the dextrin. See Gum [British] for another form of dextrin.