626 CALICO-PRINTING 



Albumen 0'40 



Biliary resin ........ 8*80 



Another analysis gives the total constituents of 100 parts of cow-dung as follows : 

 Water, 69'58 ; bitter matter, 074; sweet substance, 0'93 ; chlorophyll, 0'28; albu- 

 min, 0'63 ; muriate of soda, 0-08; sulphate of potash, 0'05; sulphate of lime, 0'25 ; 

 carbonate of lime, 0-24 ; phosphate of lime, 0'46; carbonate of iron, 0'09; woody fibre, 

 26-39; silica, 0-14; loss, 0-14. 



According to M. Koechlin's practical knowledge on the great scale, it consists of a 

 moist fibrous vegetable substance, which is animalised, and forms about one-tenth of 

 its weight; 2, of albumen; 3, of animal mucus ; 4, of a substance similar to bile; 5, 

 of muriate of soda, muriate and acetate of ammonia, phosphate of lime, and other 

 salts ; 6, of benzoin or musk. 



Fresh cow-dung is commonly neutral when tested by litmus-paper ; but some-- 

 times it is slightly alkaline, owing, probably, to some peculiarity in the food of the 

 animal. 



Probably the hot water in which the calico-printer diffuses the dung exerts a 

 powerful solvent action, and in proportion as the uncombined mordant floats in the 

 bath it is precipitated by the albumen, the animal mucus, and the ammoniacal salts ; 

 but there is reason to think that the fibrous matter in part animalised or covered 

 with animal matter, plays here the principal part ; for the great affinity of this sub- 

 stance for the aluminous and ferruginous salts is well known. 



It would appear that the principal function of dunging is to hinder the uncombined 

 mordant diffused in the dung-bath from attaching itself to the unmordanted portion 

 of the cloth, as already observed ; for if we merely wished to abstract the thickening 

 stuffs, or to complete by the removal of acetic acid the combination of the mordanting 

 base with the goods, dung would not be required, for hot water would suffice. In 

 fact, we may observe, that in such cases the first pieces passed through the boiler are 

 fit for dyeing ; but when a certain number have been passed through, the mordant now 

 dissolved in the water is attracted to the white portions of the cloth, while the free 

 acid impoverishes the mordanted parts, so that they cannot afford good dyes, and the 

 blank spaces are tarnished. 



It seems to be ascertained that the mordant applied to the cloth does not combine 

 entirely with it during the drying ; that this combination is more or less perfect ac- 

 cording to the strength of the mordants, and the circumstances of the ageing ; that 

 the operation of dunging, or passing through hot water, completes the combination of 

 the cloth with the mordanting base now insoluble in water ; that this base may still 

 contain a very minute quantity of acetic acid or sulphate of alumina ; that a long 

 ebullition of water impoverishes the mordant but a little ; and that even then the 

 liquid does not contain any perceptible quantity of acetate or sulphate of alumina or 

 iron. 



A very able and learned memoir upon this subject, by M. Penot, Professor of 

 Chemistry, appeared in the Bulletin of the Society of Mulhausen, in October 1834, and 

 an ingenious commentary upon it, under the title of a Report by M. Camille Koechlin, 

 in March 1835. 



Experience has proved that dunging, is one of the most important steps in the 

 process of calico-printing, and that if it be not well performed the dyeing is good for 

 nothing. 



In dunging calicoes the excess of uncombined mordant is in part attracted by the 

 soluble matters of the cow-dung, and forms an insoluble precipitate, which has no 

 affinity for the cloth, especially in presence of the insoluble part of the dung, which 

 strongly attracts alumina. The most important part which that insoluble matter plays, 

 is to seke the excess of the mordants, in proportion as they are dissolved by the water 

 of the bath, and thus to render their reaction upon the cloth impossible. It is only in 

 the deposit, therefore, that the matters carried off from the cloth by the dung are to be 

 found. 



M. Camille Koechlin ascribes the action of cow-dung chiefly to its albuminous con- 

 stituent combining with the alumina and iron, of the acetates of those bases dissolved 

 by the hot water of the bath. The acids consequently set free soon become evident by 

 the test of litmus-paper, after a few pieces are passed through, and require to be got 

 rid of either by a fresh bath or by adding chalk to the old one. The dung thus serves 

 also to fix the bases on the cloth, when used in moderation. It exercises, likewise, a 

 deoxidating power on the iron mordant, and restores it to a state more fit to combine 

 with colouring matter. 



The use of cow-dung is open to some objections, amongst which are its giving a 

 certain amount of greenish colouring matter to the white mordants, and its being apt 





