Madder Bleach.—As the cotton goods emote from the weaver, they present a more or less greyish appearance, and are usually termed "greys." In this state, the cotton, in addition to its natural impurities derived from the plant, contains all those which it has acquired during the process of manufacture. These are the most important, and comprise the various matters introduced during the eizeing of the warps, such as china clay, magnesium chloride, and other inorganic subetances, etarch or flour, grease from the size. the machinery, and the hands of the workmen, and dust and dirt of all kinds. These impurities may vary from 5 to 30 per cent., or more. The natural impurities of the cotton are comparatively small, less than 1 per cent. Dr. Schnuck has carefully examined the nature of some of these, and has shown the presence of fatty and waxy matters, brownish oolouring substancee, pectic acid, and albuminous matter. The complete removal of these impurities constitutes the madder-bleach.
Stamping.—To recognize subsequently the various lots of cloth and to trace damage°, each grey piece, before bleaching, is stamped at the ends with numbers and lettere. For this purpose, any colour may be used which will be sufficiently fixed to resist the bleaching process and remain legible afterwards. Thick gas tar alone, or mixed with a little turpentine, is the most generally used. Aniline black has been introduced ; but owing to its liability to change, and its tendency to leave holes, it hae not been much adopted.
Stitching.—The pieces are etitched together in lots or bunches of five or more. Formerly, thie was all done by hand ; now, stitching machines are universally adopted. Of these, the oldest is the so-called " donkey machine," etill in use—especially in bleach-houses where rapid unstitching is a desideratum—for heavy goods and such as do not require heavy ealendering. Fig. 335 represents this machine. It consists essentially of a pair of small cog-wheels working into each otber and turned by a small winch handle. The centre of the teeth of both wheels is cut away, forming a groove in which the point of the needle reste, the eye end being supported by a small orifice in the end of a spring slide immediately opposite the wheels. The cloth to be stitched, being placed close up to the cog-wheels on the opposite side of where the needle point rests, is dragged in puckers into the latter, by turning the winch handle. When full, the needle is pushed still further through the cloth by the spring slide, taken from the machine, and the thread is drawn through by hand. If the machine is made with two pairs of cog-wheels and a pair of needles, two threads may be stitched together at a distance from each other of about half an inch. In this style
of stitching, the ends of the pieces are made to overlap. The threads are not knotted, but left pro jecting 3 or 4 in. on each side of the pieces. The etitch is a eimple coarse running stitch, and the thread is made of slackly twisted cotton, not liable to cut the cloth when subjected to heavy pressure.
In the bleach-houses of calico printworks, two mare complicated machines are in general use, that of Rayer and Lincoln, generally called the American machine, and that of William Birch, Man chester. Fig. 336 represents Birch's machine. Without entering into details, it may be said that this machine makes the common flat chain stitch, easily drawn out again when required. It is simple in its working, and is so arranged that the attendant has simply to place together the two piece ends to be sewn, and to hook one corner on the tenter hooks of the guide arm, and the other on the hooks of the feed wheel; the machine will then start itself and guide the fabric across. The ends being sewn, the guide arm unhooks itself from the pieces, falls down, and stops the machine, which is then ready far another pair of piece ends to be attached. This machine may be driven by steam power, and will enable one person to do the work of three or four with the older machines. The thread is finer and the stitch is much closer than in the case of the donkey machine. Rayer and Lincoln's machine is an adaptation of Willcox and Gibbs' arrangeraent. In using it, the ends of the two pieces to be sewn are placed tog,ether, and fixed an to the pins of the vertical wheel. On starting the machine, this wheel revolves, the pieces pass under the needle, are stamped with numbers or letters, end the ends are neatly trimmed off. In the most complete machines, fhe goods aro held both inside and outside the line of sewing, thereby securing and maintaining a perfect and even stretch of the goods. This latter paint is very important, and whatever machine be used, the tension af the thread should never be too tight, or the seam will become puckered during the subsequent bleaching processes, and, when dried, the piece ends will be scrimped and creased to a considerable extent.
Singeing.—The next operation is " singeing," which consists in burning off the fine dawn an the surface of the cloth. It is essential for all those calico goods which are subsequently to be printed in good styles and to receive fine impressions.