DUNG′ING

Syn. Cleansing . One of the principal proce es in the arts of calico printing and dyeing, its object being to free the cloth from loose matters, which would interfere with the dyeing. After the thickened mordants have been applied to the fabric and properly fixed, it is nece ary to remove the now usele thickening matter, together with the exce of mordant, which has not come into actual contact with the cloth. Formerly a bath formed of cow-dung, diffused through hot water (130° to 212° Fahr.) was always used to wash away these loose matters; but now various manufactured substances are succe fully employed for the purpose. The best dung substitutes are the arsenite and arseniate of soda, the silicate of soda, and phosphate of lime. Experience proves that, in the case of these substitutes, a final rinse in cow-dung before dyeing is advantageous. A proce very similar to ‘dunging’ is employed after dyeing, to clear and give purity to the undyed parts. This subsequent proce is distinguished by the term ‘clearing.’ Cow-dung has been used in ‘clearing’ operations, but its employment is not to be recommended. Bran scalded and mixed with water is employed for certain goods, but bleaching powder is the most generally used ‘clearing agent.’