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DYEING AND CALICO PRINTING.

2. Isopurpuric Acid.—The best results are obtained with an isopurpurateof aniline. To obtain this salt, which is formed in the dye-beck, 100 partsisopurpurate of potash are mixed with 42 parts hydrochlorate of aniline.

Wool which has previously been boiled for two hours in the ordinarymanner with 4 parts of alum and 1 cream of tartar takes rapidly a chestnut-brown colour. Silk mordanted with alum (to which one-tenth of its weightof soda crystals have been added) dyes up a rose with a violet tinge in theisopurpurates of potash or ammonia, but a deep garnet brown with theisopurpurates of baryta or aniline.

3. Rosolic Acid.—Jourdin heats phenate of soda with peroxide of mercuryto a little above 150° C. for ten minutes, and obtains thus a rich red solutionof the rosolate of soda.

Kolbe mixes in a tubulated retort 1 part of oxalic acid, ij of carbolic acid,and 2 of sulphuric acid, and heats to 140° to 150° C. for 4 to 5 hours. Thered-brown residue, as soon as it _begins to swell up, is thrown into waterand boiled, adding fresh portions of water till the odour of carbolic aciddisappears. The deep-brown paste which remains undissolved, dissolves inammonia with a magnificent purple colour.

4. Fol’s Yellow.—This colour, derived from carbolic acid, is of an acidnature, and forms red compounds with bases. To prepare it heat for twelvehours, at ioo° C. in an open cast-iron boiler, 5 parts of carbolic acid and 3 partsof arsenic acid, dried and finely powdered. The colouration appears at theend of two hours, and increases gradually in intensity as the matter thickensand gives off steam. After 12 hours the temperature is raised to 125° C., andkept at that heat for 6 hours. When the mass ceases to swell up 10 parts ofacetic acid at 7 0 B. are added. The mass is dissolved in abundance ofwater, the solution is filtered through calico, and mixed with salt in excess,which precipitates the colouring matter in flocks. It is purified by combiningwith baryta and decomposing the barytic salt with sulphuric acid. The pureproduct separates out in the form of reddish-brown lamella:. It dissolveseasily in cold and hot water, ether, alcohol, and wood-spirit. In presence ofcaustic or carbonated lime or baryta it dyes wool and silk all shades of red.These colours are not affedted by soap. If used alone it gives varied shadesof yellow. It is frequently employed along with rosolic acid and other coloursto produce browns.

5. Campo-Bello Yellow is prepared by a secret process by Schrader andBerend, of Schonefeld, Leipzig. It is a derivative of carbolic acid, and isadvantageously used in wool-dyeing. It produces all shades of yellow, andresists solutions of carbonate of soda at 20° B. For use it is dissolved inboiling water and filtered. The solution is boiled, and the wool plunged forhalf an hour in the boiling liquid ; 300 grms. of alum may be added for each5 kilos, of wool. Campo-bello yellow mixed with magenta, indigo, &c.,yields a variety of useful colours.

6. Phenicienne.—The nitro-sulphuric acid employed in preparing thiscolour consists of 2 volumes of common oil of vitriol and 1 volume of nitricacid, at sp. gr. 1-35.

7. Chloride of Benzyl.—Lauth and Grimaux have obtained a fineviolet by the diredt adtion of chloride of benzyl upon rosaniline, and whenHofmann’s “Violet R” is used in place of rosaniline a violet is formed of adecided blue shade. For the preparation of chloride of benzyl an apparatus