598

DYEING AND CALICO PRINTING.

No. 16 b. Yellow .—

Tragacanth mucilage. ij gal.

(3 gals, water to 2 lbs. gum tragacanth.)

White starch. 6 lbs.

Water . § gal.

Boil well together, and add—

Tartaric acid. 6 lbs.

Citric acid . 5 ,,

Nitrate of lead .10 „

Instead of tartaric and citric acid, hydrofluosilicic acid may be used, which ismuch cheaper.

No. 17. Green Discharge {Machine ).—

Blue, No. g . ij gals.

Yellow, No. 14 . 1 gal.

Any of these discharges, as may be required, is printed in, and when drythe pieces are run through the “ decolouring vat," which is composed asfollows :—•

No. 17 a. Green Discharge .—

No. 16 b. Yellow... 3 gals, ij qts.

Mix up well with—■

Bleu de Paris, in paste. 2j to 3J lbs.

No. 18.—

Water .1000 gals.

Chloride of lime.1000 lbs.

Stir well, till quite free from lumps and coarse fragments. A frame, withwooden rollers at top and bottom, is then set in the liquid, which is kept con-stantly stirred up, so as to be perfedtly homogeneous. The pieces are thenrun through the liquid at the rate of one (28 yards) in three minutes. Afterpassing through the squeezing-rollers they are passed into water and rinsed,and then winced for ten minutes in solution of bichrome, at 4° Tw. They arenext washed in pure water, and again in water soured with muriatic acid;washed again, and dried. Except where the discharges have been printed on,the Turkey red is not perceptibly affedted, but in those places it is dischargedthe design either remains white, or a mineral colour—blue, yellow, green, &c.—is left in place of the red.

Eighth Style.—Steam Colours.

This style embraces those colours which are developed and fixed by steam.The experiments which first led to the adoption of this process were madewith dry heat. As these attempts were unsatisfadtory, steam was introduced,though it was at first apprehended that the colours would run. Its adtion issimply that of heat combined with moisture, both being regular and undercontrol. The modes of steaming vary greatly in different establishments.In some works, before steaming, the pieces are exposed to the air, at commontemperatures, for a day and a night; whilst in others the calico goes diredtfrom the machine to the steam-chest. The degree of moisture in the steamvaries also greatly, some pradtical men using it very dry, and others damp,being of course guided by the quality of the goods, the nature of the colours