APPENDIX.

689

The turpentine is first heated along with the olein ; then the soap is placed ona levigating-slab, and the mixture of turpentine and olein is gradually incor-porated with it. When this is complete the lamp-black, previously groundand sifted, is worked in. Lastly, the Paris blue is gradually ground in, andthe oxalic acid and water, which are previously mixed and slightly warmed.The Paris blue and oxalic acid may be replaced with a neutral extradt ofindigo.

New Iron Mordant.

Dissolve—

Chromate of potash.200 grms.

Oxalic acid .200 „

Green vitriol . 6 kilos.

Water.. .. ,. 6 litres.

New Aniline Red. »

Acetate of aniline is mixed with ammoniacal oxide of copper and saturatedwith sulphuric acid, when a fine purple-red colour is developed. After con-centration the liquid, on standing, deposits crystals of sulphate of ammonia,which are filtered off. The new aniline red remains then transparent.

Printing Aniline Colours on Calico.

A solution of gelatin is prepared, containing 50 grms. to the litre of water.Solution of bichromate is then added, drop by drop, till a straw-colour is pro-duced. The aniline colour is then added, and the mixture thickened withdextrin or torrefied starch. After printing, the pieces are exposed for somehours to light, which renders gelatin insoluble when in contadt with chrome.The gelatin may be replaced by a solution of casein in a small quantity ofammonia.

Use of Epsom Salts in Dyeing.

In dyeing wool for goods which are required to be “ milled ” the addition ofEpsoms gives greater permanence to the aniline colours, especially Primulaand methyl violets. The addition of sulphurous acid is also advantageous.

Test for Saffranin.

If a few particles of the suspedled colour are mixed with 2 drops of con-centrated sulphuric acid in a porcelain capsule, and stirred, a splendid bluecolour immediately appears. The addition of 2 drops of water converts theblue to an emerald-green.

Cochineal-Red on Cotton.

To 10 lbs. of the yarn, &c., take 10 ozs. of tannin, and dissolve it completelyin boiling water. Steep the goods over-night in this liquid. Prepare somered liquor at 12° Baumd, and put into a small tub a sufficient quantity to work2 lbs. of cotton yarn. Work the yarn for ten minutes. Fill up the red liquorto its original quantity, and work 2 lbs. more, and so on until the whole of thecotton has been mordanted. It is then allowed to dry, with frequent turning.Piece-goods are winced for an hour in red liquor of the same strength. When