Muslin Finisbing.—With the finest book muslins, the starching is still done by hand. Each single piece is dipped int,o the decoction of starch and blue, and well kneaded ou a table. The starched piece is now taken t,o a moderately heated room and " aired." Two girls open out the piece, and, holding each end, sway it to and fro for a short time to dry it partly ; it is then crumpled up again, pressed well t,ogether in the hands, and re opened out, and the process is repeated till the starch is deemed to be sufficiently well worked into the fibres. The piece is now t,aken to two other girls in a cooler place, who, after opening it out, pass it lengthwise between them, holding each selvage, and, by a short rapid zigzag motion given- to it every balf-yard or so, straighten the weft and warp threads, so that they stand at right angles to each other. The piece is now taken to be stretched and dried on the stenter frames. Figs. 369 and 370 represent respectively the receiving and the delivering end of one of the most improved of these machines, as made by the patentees, Messrs. Duncan Stewart and Co. It is known as the " continuous clip stentering machine "; and consists of two somewhat parallel lines of framing, which guide the onward movement of two endless chains C C, made up of small brass clips which hold the selvages of the fabric. The cloth is introduced at the end II of the machine, by two girls, each holding a selvage ; here the clips open aud close automatically, gripping the selvages very tightly. At this point, the machine is constructed so as to admit of the cloth being easily inserted ; further on, however, the two lines of framing are fixed by means of screws at a greater distanc,e from each other, and the cloth becomes stretched to the requisite breadth, at the same time moving along continuously, and is delivered dried and finished at the other end D; F is the cloth passing away to the folders ; G is the engine for driving the whole machine.
In this manner, a " stiff finish " is given, the cloth feeling rigid and inelastic. The so-called " elastic finish," a special feature in certain varieties of muslin, is imparted to the pieces by the same machine, by moving the lines of selvage backward and forward during the drying and stretching on the stenter frame. This is effected by a crank motion imparted to the whole machine at E, which causes the weft and warp threads of the fabric to rub against each other till dry, thus preventing them frorn becoining united. Dried in this rnanner, the goods possess a characteristic and remark able elasticity. The drying portion of the machine consists of rows of steam pipes situated imme diately below the piece; or, as is very usual, a blast of heated air is slriven against the piec,e from below, and fanners are placed above, at certain distances from each other. For this muslin-finish. fine wheat starch, boiled with water containing a small proportion of alum in solution, and a suitable quantity of smalts blue, is used ; ultramarine is inadmissible, owing to its being destroyed by the acidity of the starch.
Nottingham lace, harness curtains, and similar materials, are starched by spreading thern out on large tables covered with blanket and canvas, on which a thin layer of boiled starch and blue has been previously spread by means of brushes. When the fabric is extended on the table thus prepared, it is brushed over in order to press in the starch, which thus coats only one side, leaving the figured thicker portion to stand out clear and white from the more open groundwork, which is blueish.
Yarn and Thread Bleaching.—In the form of yarn and thread, cotton is free from size, grease, &c., and the proc,ess is consequently less severe than for cloth. The lime boil is entirely dispensed with, and there are slight modifications in the machinery employed. The yarn chains are " warps," used for weaving winceys, shirtings, gingharns, &c. As they come to the bleacher, they vary in length from 50 to 15,000 yds., but are usually plaited five-fold in loose manner ; the bleacher plaits them five-fold again, so that the chain is reduced considerably from its real length, and is thereby rendered more manageable. This plaiting is done very loosely and rapidly by hand, though there are machines which plait three-fold. If the yarn is in hanks, these are linked together in a simple manner, to form a long chain, though they are still, in many bleach-houses, handled as separate hanks throughout the process. If the yarn is in the form of " cops," ready for the weaver's shuttle, these are packed as carefully and tightly as possible into pure hempen bags, containing 16 to 201b. each, and are sewn up.
The following is a sketch of the bleaching process, as used for 3000 lb. of cotton yarn, em ploying open low-press kiers :— I. Ley boil : 60 galls. caustic soda, at 32° Tw., 400 galls. water, boil 6 hours and sweeten hour.
2. Wash,through washing machine.
3. Chemick : bleaching powder solution, 2° Tw., 2 hours under sieve, wash hour under sieve.
4. Sour : sulphuric acid, 1° Tw., hour under sieve, wash hour under sieve.
5. Wash through washing machine.
6. Run through dumping machine, with hot soap liquor and blue.
7. Hydro-extract and dry.
Cotton thread is treated in the same way ; but, on account of its closer and finer texture, the first five operations are repeated before passing to the sixth, using for a second ley boil about 8 galls. caustic soda at 32° Tw., or 30 lb. soda ash.
The chernicking, souring, and washing are performed in stone tanks having false bottoms and perforated drainers or sieves above, the liquors being made to circulate from a well below, by means of pumps. Fig. 371 shows this arrangement. E is the cistern with a false bottom F, and a valve G communicating with the tank D below ; B is the shaft which drives the pump C, for raising the liquor up to the drainer F' ; A is a winch for drawing the pieces into the cistern. The drainer may cover the whole surface of the cistern, and can be lifted up with hinges when introducing or withdrawing the cloth. For the sours, the drainer is made of wood ; for the ohemick, of sheet zinc. The washing machine referred to is similar to the one described under " madder bleach." The drying machine for the chains is also similar to those described, but is fitted up at each end with peg rails, to guide the chain spirally while it is moving several times from end to end between the drying cylinders. Just before drying, the plaiting is unloosed, so that the chain is dried in simple chain form. Hanks and cops are dried in stoves heated to about 71° (160° F.), the forrner being suspended on poles, the latter placed on trays made of galvanized wire netting.