59 °

DYEING AND CALICO PRINTING.

Finally, other colours are produced upon the white portions. The red ismadder; the yellow portions are chromate of lead, which also produces thegreen when applied upon the blue portions, and the orange when appliedupon the reds. These patterns have been printed at the establishment ofMessrs. Wood and Wright.

The following method of applying indigo, simultaneously with mordantsfor madder and garancin, producing thus a variety of novel and strikingeffedts, was invented and patented by Mr. J. Lightfoot (Specification No. 3668,Dec. 26, 1867). The patentee prepares a pulp of indigotin and tin by anyof the following methods :—He takes dry indigo, ground and prepared, 1 \ lbs.,or if indigo-pulp is used such a quantity as may be equal to that weight ofdry indigo; tin crystals, protochloride of tin, lbs.; caustic soda, at 30° Tw.(or caustic potash, at 40° Tw.), 1 gal. These materials are put in the colourpan, and raised to a boil in half an hour, when 1 gal. of boiling water isadded. The mixture is then allowed to become quite cold, and 3 gals, of cold

Indigo Style. (First Stage).

water are added, in which £ lb. sugar has been previously dissolved. To thissolution he adds 2\ pints of muriatic acid, at 32° Tw., or 1 pint of ordinarysulphuric acid, previously diluted with 1 pint of water, and allowed to standtill clear and cold; or 3 quarts of acetic acid at 8° Tw. The indigotin mayalso be precipitated by a mixture of protochloride of tin solution (doublemuriate), at 120 0 Tw., with any of the acids above named, taking \ pint ofof the tin solution to half the quantities of acids given above. Of all theseprecipitants, acetic acid alone is preferable. The indigotin precipitate isfiltered through a deep conical filter, leaving as small a surface exposed to theair as possible. The pulp from the above quantities, when filtered, shouldmeasure about 1 gal.

To make a blue colour for printing the patentee takes 4 gals, of the aboveindigo-precipitate and 14 lbs. gum Senegal in powder, stirring till dissolved ;the colour when strained is ready for printing.