Thread is a stronger kind of yarn. Whether or not it is composed of a greater number of filaments, it is twisted more closely, and has a harder and smoother surface. Most of it is used in needlework, as sewing•thread ; but some is employed in net and lace making, and in other ways, though seldom in actual weaving. The manufacture of thread was first attempted in this country by Mrs. Millar, of Balgarran, in 1722, on having received some information and machinery from Holland. Her example was speedily followed by several families in Paisley, where the manufacture soon became of considerable impor tance. The first manufacturers imitated the kind called Nuns' or ounce thread, which was made up in hanks of forty threads each, reeled upon reels a yard in circumference; but when the profits of the manufacture were diminished by competition, it was injured by the surreptitious practices of some of the manufacturers. It was even deemed necessary, in 1788, to pass an act of parliament requiring all manufacturers of thread to use uniform 'standard reels of thirty-six inches in circumference, and to put thirty threads or rounds of the reel in each hank.
The manufacture of thread from fibres of cotton-wool, for sewing and other purposes, is one of the many important departments of British industry called into exercise by the improvements effected by Arkwright and his successors in spinning-machinery. The operation of combining yarns of cotton or linen into thread is performed by a machine called a doubling and twisting frame, somewhat resembling the throstle of the cotton-spinner. Along the centre of the machine is an elevated creel or frame-work, which supports two parallel rows of cops or bobbins of yarn. The cops are placed vertically, or nearly so, and the lower ends of their axes rest in oiled steps or hollows, while the upper ends are supported by wire eyes, so that they may revolve with facility. The number of cops is twice as great as that of the twisting spindles when the thread is to consist of two yarns, three times RA 'great for thread formed of three yarns, &c. The yarn with which they are charged is frequently gassed, or passed quickly through a series of gas flames, to singe off any loose downy fibres. From the cops the yarns are conducted over horizontal glass rods, which are fixed parallel with the creel, and thence downwards into troughs filled with water or very thin starch-paste. To ensure the equal moistening of the yarns they are, while being drawn through the troughs, made to pass either under a glass rod, or through eyes. After being wetted the yarns pass over the rounded edge of the trough, which is covered with flannel for the purpose of absorbing the superfluous moisture ; and thence under And partly around an irou roller, which is made to revolve with any required velocity by a train of wheel-work. Upon this roller rests another, of box-wood, which revolves solely by contact with the iron roller, its axis playing In vertical slots. In passing under the iron roller, then between it and the wooden roller, and finally over the latter, the yarns required to form the thread are brought together and slightly compressed; but although thus prepared for a more intimate union, they are not yet twisted together. In the annexed figure a a repreeenta the united yarns which are to form the thread, and b is a fixed eylet through which they are conducted to the flyer c, which is mounted upon and revolves with a long vertical spindle set in motion by a whorl or pulley and strap at d. e is the bobbin upon which the
finished thread is wound by the revolution of the flyer, which also gives to it any predetermined degree of twist. The spindle passes freely through a bolo in the centre of this bobbin, which rests upon a bar called the copping-mil, the transverse section of which is indicated by a tint in the cut ; and the copping-rail, which extends the whole width of the machine, is supported at intervals by vertical rods, one of which is shown at f. To these rods, and consequently to the copping rail and bobbins supported by them, a reciprocating vertical motion is imparted through the connecting pieces g and le, from the bent lever i i, which is pivoted at k, and receives its motion through the adjustable friction-roller 1, from an eccentric or heart wheel nr. Thus by the combined rotatory motion of the spindle and flyer, and the rising and falling motion of the bobbin, the thread is at once twisted and wound regularly upon the bobbins, which may be easily removed when full. By changes in the relative sizes of some of the toothed wheels by which the moving-power is distributed from the main shaft, the spindles, which always revolve much faster than the rollers, may be made to do so to any required degree, so as to impart a greater or less degree of twist to the thread.
These few illustrations will suffice to show the nature of the twist Rig processes, aided by details given in such articles as COTTON; LINEN; SILK ; Sl'INNING ; and WOOLLENS. We may, however, mention that the polishing of sewing thread is a process on which its saleable quality much depends. Mr. Adam, of Paisley, polishes sewing thread by pass. ing it through a dressing composition, over a guide roller, through the teeth of a reed, over a metal drum, under a brush roller, again through a reed, and ,finally under a polishing roller covered with cloth. Mr. Brooks, of Derby, has invented a mode of producing a polish on thread, which he called patent glace ; and the assumption of the name glace thread by Mr. Evans, of Huddersfield, led to litigation between the two inventors. The polishing of sewing thread has indeed led to more than one appeal to the law. Mr. Ewen patented a process, where by he clips a hank of thread into size, squeezes it, passes it over two rollers rapidly revolving, sud applies it against a cylinder-brush, which removes all asperities. Mr. Liddell, another inventor, used two sets of rollers instead of one, and teasles instead of brushes ; but in some other respects he was considered to have infringed Ewen's patent. Other appeals to the law have been made in refercneo to the length of thread wound upon a reel. A manufacturer of Persian thread put labels on his reels, denoting the quantities to be 100, 200, or 300 yards; whereas the real lengths were low. This was done at the request of Manchester firms which had lax notions of honesty. Tho manufacturer refused to continue this system ; whereupon a Man chester man pirated his trademark, and used It for short-measure cotton thread obtained elsewhere—thus committing a double fraud.
The exports of yarn and thread have now reached an enormous quantity. In 1860 there were exported :—