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DYEING AND CALICO PRINTING.

YELLOW MINERAL PIGMENTS.

Of these we have the following:—Two iodides ; that of lead and the yellowiodide of mercury. Sulphides: orpiment, a peculiar sulphide of arsenic;sulphide of cadmium; the yellow-orange sulphide of antimony; and bisulphideof tin. Oxides: hydrated oxide of tin; crocus martis, a yellow hydratedoxide of iron; massicot, oxide of lead; and oxide of uranium. Salts: Naples’yellow, an antimoniate of lead ; uranates of soda and potash ; the insolublechromates of lead, bismuth, zinc, baryta, strontia, and lime; Cassel yellow, anoxychloride of lead ; antimony yellow, an intimate mixture of the oxychloridesof lead and bismuth and of antimoniate of lead. Metals: gold; and so-calledDutch gold, an alloy of copper and zinc and of copper and tin, manufa&uredchiefly at Nuremberg, in Bavaria.

This list contains a large number of mineral yellows employed exclusivelyas oil-paints ; others may be fixed to woven tissues by the aid of plastic sub-stances ; and, finally, the list includes the peculiar class of colours whichadmit of dire< 5 t precipitation upon the fabric. These are the insoluble chromecolours, produced by an application, first, of subacetate of lead, and subsequentimmersion in a bath of neutral chromate of potash.

In the year 1820 the use of chromate colours was first attempted byM. Lassainger. He steeped skeins of prepared or de-gummed silk in aweak solution of subacetate of lead for about two hours. The silk was thenwashed in clean cold water, and immersed in a dilute solution of neutralchromate of potash. Upon this principle is based the application of thesoluble chromates in dyeing and calico printing. These colours are readilydetected by their property of becoming tinged a deeper orange by the a&ionof ammonia and of lime water, while acetic or citric acids restore the yellowcolour. Alkalies and strong hydrochloric acid permanently destroy thesecolours.

The subjoined specimen of chrome-yellow or canary-yellow, printed uponcotton by Messrs. Walter Crum and Co., is an illustration of the use ofchromate of lead. The colour is produced upon the cloth by the followingprocess:—24 ozs. of white sugar of lead are dissolved in each gallon of water,and thickened with 4 lbs. of British gum. This solution is printed on to thecloth, which is then dried and passed for two minutes through a cold bath ofbichromate of potash and common salt containing 6 ozs. of bichromeand 24 ozs. of salt to the gallon. The cloth is finally well washed and dried.

Another shade of yellow may be obtained on yarn by a treatment which ischemically the same. 25 lbs. of cotton yarn are run through a bath of 2 lbs.of sugar of lead for twenty minutes; then through a weak lime water bath.The yarn is removed from the lime bath at the end of five minutes, wrung out,and passed through a cold bath of 1 lb. of bichromate of potash and’ 1 lb. ofhydrochloric acid.

If buff may be considered a shade of yellow, we may here detail how thecolour known commercially as iron-buff is produced. This colouris illustratedin the subjoined specimen of printed cloth, likewise obtained from the samedistinguished firm.

There is first prepared a “ standard liquor,” from which in several pro-portions with the thickening almost as many shades can be obtained. 4 lbs.of copperas or sulphate of iron are dissolved in each gallon of water, to which