11. " Intermediate" or " Second Slubbing."—Is in all respects a repetition of the above ; necessary in cases where the most even and clean yarn is required. It is not ordinarily used in the production of low numbers.
12. " Rovine—This is a continuation of the preceding, its principal object being to still further attenuate the sliver. At this point, also, the latter receives additional twist, to enable it to bear the slight strain necessary to draw it from the " spool," without the formation of uneven places.
13. " Spinning."—The concluding process of the series. The sliver is here attenuated to the required fineness, and is given the twist hy which the thread is completely formed.
11. " Doubling."—In this series, may he included the process of doubling, it being much more akin hereto than to manufacturing. It is a large and increasing business, often carried on in conjunction with spinning, but frequently found quite apart. It is a method of combining two or more threads to form a single cord ; and is adopted in the production of rnany vaiieties of yarn, which are used for widely different purposes.
The above processes, and the machinery necessary thereto, will be described in the order given, excepting, however, the first two, which will he dealt with in treating of the production of the raw material (see Fibrous Substances). In performing this task, it is not intended to allude to obsolete methods and machines, unless such reference will tend to elucidate the principles on which the modern system is based. Even with this limitation, it will not be possible to make a general reader acquainted with every variety of machine that has met with, and still retains, a certain amount of favour.
The Cotton ofai.—The considerations that influence the selection of a locality in whioh to erect a cotton mill are chiefly the following :—Firstly, proximity to an abundant store of cheap and good fuel ; secondly, an unfailing supply of water, or means of preserving it ; thirdly, easy and cheap means of access to the market, by road, water, or rail ; and, fourthly, an area within which an experienced class of operatives can be obtained. There are several other minor points, but they need not be detailed. As many as possible of these conditions should be found in the locality selected, as all are highly important, and greatly conducive to success. The choice of site should be carefully considered. A valley, protected from dry wiuds, and open to moist ones, is of great advan tage. The subsoil should be of stiff, impervious clay, such as will retain the moisture in a subter ranean reservoir, the evaporation from which will be constantly moistening and softening the atmosphere--advantages that have been previously explained.
The fittest materials for the structure will be dictated by the circumstances of the loca Ay; on in the presence of the conditions prescribed above, brick will generally be formd most suitable and economical. Should it be requisite to provide a reservoir for water, ally clay excavated for this purpose, as well as from the foundation trenches, can be utilized for the manufacture of bricks.
The methods of construction are various. The one formerly common—and, perhaps, even now cheapest in first cost—was a combination of brick or stone with timber. Another is the so-called " half fireproof " plan, in which that portion most liable to destruction by Ore—until recently, considered to be that in which tilts preparatory machinery is worked—is constructed as far as possible without timber. But of late years, owing to the high speeds attained, the danger has extended to the mule-roorn. This experience has given rise to the most modern, and now generally approved, system, in which the whole structure is fireproof. There are several ways of attaining this end.
The mill shown in Figs. 522, 523, and 524, 41 om drawings kindly furnished by A. H. Stott and Sons, mill architects, of Manchester and Oldham, is thoroughly representative of recent constructions, such as prevail in the great spinning districts of South Lancashire.' The dimensions of the main portion of the structure would be about 295 ft. by 125 ft., accommodating 75,000 spindles, and the usual complement of machinery in connection. The foundations are of coarse rubble, on 1 ft. of mortar concrete. Those on which the columns immediately rest are of flag-stones. The walls are composed externally of pressed brick, and internally of common brick. The window-sashes are of wood, glazed in the lower part with rough plate, and in the upper with clear glass. The floors are supported upon cast-iron columns, in which brackets or arms are cast. To these are secured rolled iron beams, the object being to get two arches in place of one. Each pillar bracket is connected with the next by an arch beam, to form a complete continuation between the pillars and the direction of the bracket. The brick arches are 7 in. thick at the base, diminishing to in. at the crown ; they are turned between the beams. Timber joists, 2i in. deep, are then laid across the beams, and the space is after wards filled up with concrete, composed of lime and furnace ashes. When this is thoroughly dry, the floors are laid with deal boards, nailed to the joists. Boarding is now generally preferred for all room floors, except the blow. ing-room. The floor of the cellar is composed of bricks, laid on puddled clay, with passages formed of cement concrete, or flag-stones. The roof of the mill is, in tho first place, constructed in the same manner as the floor ; but the concrete is laid level, and then covered with two coats of asphalt, each in. thick. These are turned up the wall, 18 in. all round, and protected from the weather by a dwarf brick wall, built inside on the asphalt. Constructed thus, the roof forms a reservoir, containing 6-12 in. of water. The object of this is to render it thoroughly fireproof. Iu some cases, 12-18 in. of water is preserved, and arrangements are made for utilizing it at a moment's notice in the event of fire. When this plan is adopted, conduit pipes are laid to, and around, the interior of each room, and provided with the necessary taps. The staircase is composed of stone, with cast-iron risers.