314 DYEING AND CALICO PRINTING. 



vert and Lowe having observed, in 1856, that tanning matters would 

 precipitate and render insoluble certain coal-tar colours, further ob- 

 served, at the end of 1859, that tannin, when printed on prepared cloth, 

 and submitted to the action of the steam, would become fixed, and serve 

 as a mordant for the coal-tar colours. But it was only in 1860 that this 

 result was practically carried out by Mr. Gratrix, and although the 

 aniline purples so fixed are faster against soap than those printed with 

 albumen, they do not so perfectly resist the action of light. The pro- 

 cess preferred by Mr. Gratrix consisted in making cloth prepared with 

 oxide of tin, such as is generally used for steam colours, and after having 

 prepared it with a gall-nut solution, submitting it to the action of steam, 

 when the tannin becomes fixed and insoluble : the pieces are then passed 

 through a dunging liquor, washed, and then into a beck containing 

 aniline purple, mixed with a little acetic acid. As the bath is gradually 

 carried to the boil, the colour fixes itself on the tannin, and thus pro- 

 duces the print ; but, as the whites are rather soiled, the pieces are 

 passed into a weak acid bath, or through a weak solution of printing 

 clearing liquor, such as used for garancine. 



In 1861, Messrs. Nathaniel Lloyd and E. G. Dale introduced a pro- 

 cess, the leading feature ol which is the use of tartar-emetic as the agent 

 fur fixing aniline purple. 



Although it has been long known to chemists that aniline would 

 yield a green colour under certain oxidizing agents, up to the present 

 time all efforts to dye silk or wool commercially with it have failed, 

 but in I860, Messrs. Calvert, Clift, and Lowe introduced a most easy 

 and practical method of producing it under the name of emeraldiite, on 

 cotton fabrics. The process consists in printing an acid chloride of ani- 

 line on a cotton fabric prepared with chlorate of potash, and in a few 

 hours a beautiful bright green gradually appears, which only requires 

 to be washed. If the green fabric is passed through a solution of bi- 

 chromate of potash, this colour is transformed into a dark indigo blue, 

 called azurine. The productionof this colour directly on the fabric is most 

 important, and it will probably lead to the similar production of the 

 other coal-tar colours, without previous treatment, directly on the cloth. 

 By this means not only the great loss of aniline in the original produc- 

 tion of the colour will be avoided, but a considerable economy of mor- 

 dants will be effected. 



It is by availing themselves extensively of the pigment style of 

 printing that the French have given such an attractive appearance to 

 their display of printed fabrics in the Exhibition ; and by the aid of the 

 remarkable talent possessed by this people for combining various con- 

 trivances, such as the block, perrotine, and roller, they have succeeded 

 not onlv in producing beautiful effects, but also in perfectly imitating 

 madder and steam chintz styles, in which the colours simultaneously 

 printed by these various modes are adjusted one to the other with per- 

 fect accuracy. 



