The dyeing of textile fabrics . w Chap. XI.] IRON MORDANTS. 187 M hicli, of course, also removes the acid salt formed. Theemployment of water containing bicarbonate of hme isexceedingly advantageous for the washing, since itgreatly facilitates the decomposition of the absorbed mordant. The boiling in soap solution is necessary to completethe decomposition of the absorbed mordant, and the. Fig. Squeezing Machine used in the Mordanting of Silk. temperature employed, 100° C, is said to modify the pre-cipitated ferric oxide and render it less liable to dissolvein the successive iron baths. Ac
The dyeing of textile fabrics . w Chap. XI.] IRON MORDANTS. 187 M hicli, of course, also removes the acid salt formed. Theemployment of water containing bicarbonate of hme isexceedingly advantageous for the washing, since itgreatly facilitates the decomposition of the absorbed mordant. The boiling in soap solution is necessary to completethe decomposition of the absorbed mordant, and the. Fig. Squeezing Machine used in the Mordanting of Silk. temperature employed, 100° C, is said to modify the pre-cipitated ferric oxide and render it less liable to dissolvein the successive iron baths. According to jMoyret, no iron soap is precipitated onthe silk in this operation. Previous impregnation of the silk with tannin matterdoes not tend to cause a larger precipitation of mordanton the fibre, but rather the reverse ; indeed, the silk losesweicdit throufrh the oxidation and destruction ot theabsorbed tannic acid. 188 DYEING OF TEXTILE [Chap. Xl By one complete mordanting oj>eration the silk gainsabout 4 per cent in weight. If the operations arerepeated six times, it gains about 25 per cent, orhas about made up the loss sustained in boiling-off. Ifrepeated seven to eight times, there is a gain of about8 per cent, of the original weight of the raw silk. Thusmoixianted, the silk possesses a deep orange brown colour,and still retains its lustre. Fig. 45 represent
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectdyesanddyeing, bookye
