644

DYEING AND CALICO PRINTING.

The second pattern on p. 645 shows the production of chrome-orange in lightand dark shades, not by means of a previously-prepared pigment, but by theproduction of sub-chromate of lead in or upon the fibre itself. For a dark orangethe brown or grey sugar of lead thickened with starch is printed on, whilst fora light orange a white sugar of lead is taken, and the thickening is gum. Thecalico, before printing, is prepared with a solution of sulphate of soda or sulphateof magnesia (Epsom salts). The thickened solution of sugar of lead is nextprinted on ; after which the pieces are passed through a cold solution of sul-phate of soda, and then through “ sours ” (very dilute sulphuric acid). Theyare next washed and then “ raised ” in the so-called orange vat for three tofive minutes at a boiling heat.

The orange vat is made up with bichromate of potash, to which an excessof caustic lime has been added. Caustic soda may be substituted for causticlime. The goods are next washed, and may then be passed through coldlime-water to clear the whites.

Extract of Madder, Red and Pink, with Chrome Orange, Green,Ultramarine Blue, and Chrome Black. (See p. 643.)

In addition to the receipts for aniline blacks, pp. 213 to 215, the followingmay be useful:—Cordillot employs'—

1. As Thickener .—

Wheat-starch . 10 kilos.

Water.24 litres.

Gum-water (i‘2 kilos, per litre). 4 ,,

Tragacanth-water (65 grms. per litre) . 6 „

2. As Oxidising Mixture .—

Thickener, No. 1 17 litres.

In which dissolve—

Chlorate of potash.900 grammes.

After cooling add—

Ferricyanide of ammonium,

2'6 kilos.