368 BLEACHING 



the last finish, and is sometimes used to whiten the ground on coloured goods. The 

 whole process may be expressed thus : Wash out the soluble matter ; boil with lime 

 to dissolve still more, and to make a fatty compound with the oily matter ; wash out 

 the lime by acids ; wash out the fat with a soda-soap; clear the white by chloride 

 of lime. 



The impurities in the cloth have a certain power of retaining colour upon them. 

 Mud and dirt, as well as grease, gluten, and albuminous matters, have this property, 

 and fatty soaps, such as lime-compounds of fatty acids. The pure fibre, however, 

 has no power of taking up solutions of such colouring-matter as madder. When, 

 therefore, it is desired to try the extent to which cloth has been bleached, it is dyed 

 or boiled up with madder exactly as in the process of dyeing. It is then treated with 

 soap, as the madder-dyed goods are treated, and if it comes out without a stain, or 

 nearly pure white, the goods are ready. Dyers or calico-printers who dye printed 

 goods are exceedingly particular as to the bleaching, the dyeing and printing having 

 now approached to such exactness, that shades invisible to any eye not very much 

 experienced are sufficient to diminish in a material degree the value of the cloth. 

 Any inequality from irregularity of bleaching, which causes a similar irregularity of 

 dyeing, is destructive to the character of the goods. Many patterns, too, have white 

 grounds ; these grounds it is the pride of a printer to have as white as snow. If 

 delicate colours are to be printed, they will be deteriorated if the ground on which 

 they are to be printed is not perfectly white. 



The stains which come out upon maddored goods in consequence of defective 

 bleaching are sometimes called spangs. Their origin is such as I have described 

 above, as the following statements of facts will show. The weaver of calicoes receives 

 frequently a fine warp so tender, from bad spinning, or bad staple in the cotton, that 

 it will not bear the ordinary strain of the heddles, or friction of the shuttle and reed, 

 and he is obliged to throw in as much weft as will compensate for the weakness or 

 thinness of the warp, and make a good marketable cloth. He of course tries to gain 

 his end at the least expense of time and labour. Hence, when his paste dressing be- 

 comes dry and stiff, he has recourse to such greasy lubricants as he can most cheaply 

 procure, which are commonly either tallow, or butter in a rancid state, but the former, 

 being the lowest priced, is preferred. Accordingly, the weaver having heated a lump 

 of iron, applies it to a piece of tallow held over the warp in the loom, and causes the 

 melted fat to drop in patches upon the yarns, which he afterwards spreads more evenly 

 by his brush. It is obvious, however, that the grease must be very irregularly applied 

 in this way, and be particularly thick on certain spots. This irregularity seldom fails 

 to appear when the goods are bleached or dyed by the common routine of work. 

 Printed calicoes, examined by a skilful eye, will be often seen to be stained with large 

 blotches, evidently occasioned by this vile practice of the weaver. The ordinary 

 workmen call these copper stains, believing them to be communicated in the dyeing- 

 copper. Such stains on the cloth are extremely injurious in dyeing with the indigo-vat. 



Old Methods still in use. As a specimen of the older processes, we shall give the 

 following, adding, afterwards, a minute account of some of the plans adopted by the 

 most successful bleachers. When grease stains do not exist, as happens with the 

 better kind of muslins, or when goods were not required to be finely finished, the fol- 

 lowing has been adopted : After singeing, 1. Boiling in water. 2. Scouring by the 

 stocks or dash-wheel. 3. Bucking with lime. 4. The bleaching properly so called, 

 viz., passing through chlorine or crofting. 5. Bucking or bowking with milk of lime. 

 These two latter processes employed alternately several times, till the whole of the 

 colouring-matter is removed. 6. Souring. 7- Washing. 



Another routine has been, 1. Cleansing out the weavers' dressing, by steeping the 

 cloth for twelve hours in cold water, and then washing it at the stocks or dash-wheel. 

 2. Boiling in milk of lime, of a strength suited to the quality of the goods, but for a 

 shorter time than with the soda lye ; two short operations with the lime, with inter- 

 mediate washing, being preferable to one of greater duration. 3 and 4. Two conse- 

 cutive lyes of ten or twelve hours' boiling, with about 2 Ibs. of soda crystals for 1 cwt. 

 of cloth. 5. Exposure to the air for six or eight days, or the application of chloride 

 of lime and then sulphuric acid. 6. A lye of caustic soda. 7. Exposure to the air 

 for six or eight days, or chlorine and acid as above. 8. Caustic soda lye as before. 

 9. Chlorine and the sour. 10. Rinsing in hot water, or scouring by the dash-wheel. 



The Processes used in Bleaching. Singeing. The singeing is performed by passing 

 the cloth over a red-hot plate of iron or copper. The figure 108 shows this apparatus 

 as improved by Mr. Thorn. At a there is a cylinder, with the cloth wound round 

 it to be singed ; it passes over the red-hot plate at b, becomes singed, passes over a 

 small roller at c, which is partly immersed in water, and by this means has all the 

 sparks extinguished ; then is wound on to the roller d, when the process is finished. 

 As the products of combustion from the singeing are sometimes very unpleasant, they 



