3oo

DYEING AND CALICO PRINTING.

the composition of the water employed and the peculiar nature and richnessof the dyeing material are prominent. All the different kinds of madder metwith in commerce do not adt in the same way in the dye-beck, and even when ofthe same origin its behaviour may be influenced by natural causes, good orbad season, for instance, during its growth, or by adulteration. To this wemust add that the different commercial preparations of madder (fleur degarance, garancin, &c.) each yield results peculiar to themselves, and it willbe clear that each of these substances requires a specially modified treatmentin the dyeing operation.

From these few observations it will be readily understood that a manu-fadturer has first and foremost rigorously to study, and next bring into pradtice,the most suitable conditions for the duration of the immersion of the cloth,the temperature to be given to the contents of the dye-beck, the mode ofheating, &c.

Before we review each of these conditions separately, we may yet mentionthe following generalities:—The art of madder dyeing (French, garangage)has been, indeed, in our days brought to so high a degree of perfection, that it isdifficult to think that it can be further improved. We can daily admirethe beautiful execution of tissues, perfectly got up, where upon a groundof dazzling whiteness there are designs in rose-red, red, lilac, violet, brown,or black tints, and shades of the utmost brilliancy, and, moreover, sofast as to admit of strong and repeated washing. These results havebeen obtained by the joint efforts of the many intelligent men who havedevoted their time and capital to this branch of industry. The introdudtionof resin soap in the bleaching process has rendered the getting up of whitegrounds after the dyeing process far more readily obtainable. A better andmore intimate knowledge of the mordants and the processes for fixing thesame, the substitution of the silicate of soda for cow-dung in many cases,have all contributed to a more regular and more complete fixing of themetallic oxides (mordants), and hence to better results ; the dyeing processhas been greatly benefitted by the introdudtion of those madder produces knownas fleur de garance, garancin, commercial alizarin, &c. Lastly, the clearing(avivage) has become a more speedy and far more manageable operation by theskilful application of chemicals. All pradtical dyers agree herein, that the dyeingoperations with fleur de garance, garancin, and similar produdts require less careand are far more easily executed than that with madder, and therefore we willturn our attention first to the latter substance, quoting succindtly the resultsof the remarkable researches and labours of M. H. Schlumberger* on thissubjedt, who fully investigated one by one each of the conditions most favourableto obtain good results.

First, as a necessary condition it should be borne in mind that the clothto be dyed should be thoroughly well prepared in every respedt, wellcleared, and its mordants well fixed. As to the duration of the madderdyeing, the goods may be left in the dye-beck for six hours without fear ofdeterioration of the colours produced, but since labour, fuel for heating, andloss of time are important matters, and since it is a well-known fadt than anequally good result can be obtained in less time and with a decided gain inmany respedts, we may state that four hours is sufficient to all intents and

* “ Bulletin de U Societe Industrielle de Mulhouse,” vol. viii., p. 327.