650

DYEING AND CALICO PRINTING.

than with chlorate of potash alone. When I impregnate a fibre or pad fabricsin a soluble chlorate which I dye in or print upon with a colouring matter tobe oxidised, as e.g. in the aniline black, when I want to secure the greys, 1can hasten the oxidation by adding to the colouring matter to be oxidised, orin the aniline black colour, 2 or 3 per cent of a salt of oxide of iron, copper,chrome, or manganese. I also use chloric acid, combined with aniline or itshomologues, for the produdtion of black or grey colours. I decomposesulphate, oxalate of aniline, or similar salts, with chlorate of barytes, lead,lime, strontian, so as to produce by double decomposition chlorate of anilineor its homologues, which, printed or dyed upon fabrics or yarns, produces fastblacks or greys by ageing; and in this case I find also an advantage in addingto the aniline 2 or 3 per cent of a salt of iron, copper, chrome, or manganese.Animal matters do not take easily colours formed by oxidation. I surmountthis difficulty by fixing in the fibre metallic oxides, such as copper, alone orcombined with chrome, and then the animal matter takes aniline blackcolours. I find an advantage in preparing the animal matters which have tobe dyed or printed with aniline black in the following mixture:—1 lb. sulphateof copper, i lb. chlorate of soda, i lb. bichromate of potash, and 1 gallon ofwater.”—(Specification No. 2859, November 6, 1865).

In another patent the same chemist recommends the use of—“ Insolublebinoxide of chromium, or insoluble or soluble chromate salts capable ofevolving chromic acid, either slowly, in the presence of water or certain acidsor alkalies, or simply by ageing or steaming; and I find it of great use in theprodudtion of aniline and its homologous black or grey colours, in which I mixa salt of aniline and the brown binoxide of chromium, either alone or in con-junbtion with a chlorate, and such mixtures printed upon cloth produce fastaniline black by ageing. The following proportions have given me very goodresults :—First, 12 ozs. chloride of aniline, 3 lbs. of water, and 1 lb. of starch,boiled together; secondly, 8 ozs. of brown binoxide of chromium in paste,and 4 ozs. of chlorate (of what base the patentee does not state), to 1 gallonof thickening. The colour for printing is a mixture of equal parts of thesetwo compositions. If I want to dye or print very heavy objedts, I can easilyproduce the necessary quantity of binoxide of chromium in the fibre by paddingor dyeing first in a solution of a sulphate or chloride of chromium, and thenpassing the goods through a solution of monochromate of potash; then dyein a salt of aniline. The chlorate hastens the produdtion of the colour, butthe binoxide of chromium and the salt of aniline can be used alone, and givevery good blacks ; but in this I find an advantage in introducing in the colourfrom 3 to 5 per cent of arsenic acid, which in this case assists the decompo-sition of the binoxide of chromium.” — (Specification No. 1174, April 26,1866).

Murexide Purples.

Like the aniline blacks, the murexide shades do not fall naturally under anyof the above great styles. Upon cotton the following formula gives a deep

shade:—

Gum-water. 1 litre.

Nitrate of lead .400 grms.

Crystalline murexide. 1 grm.