The laps are taken to the carding-machine, consisting of a series of cylinders revolv ing in a frame, and placed so close together that they almost touch each other. Each cylinder is covered with a coating of fine steel wire points, which are stuck in leather, or some other flexible material, and are technically called cards. The production of these cards by machinery is in itself a marvel, and the automatic machines for making them are wonderfully effective. Each piece of wire is bent and put through two holes in the leather so as to form two points on the other side, and these are slightly bent all in one direction. There are many variations upon this arrangement ottlie wires, but the general principle is the same in all. The machine for making the cards cuts the wire to the right lengths, bends them, pierces the holes in the leather, inserts the wires, and finishes by giving them the slight sloping direction which is essential.
The lap is made of the same width as the cylinders of the card-machine, and is so adjusted that, as it unwinds from its roller, it passes in between a pair of the carding cylinders, the steel wire teeth of which seize hold of the individual fibers, and drag them in one direction until they arc caught by other cylinders, and so carried from one to another, always being pulled in a straight direction until they are laid as nearly as pos sible side by side, and are given off in a thin cobweb-like film at the last cylinder, where it is prevented from continuing its journey round the cylinders by a small bar of metal called the doffer, which, with a gentle and peculiar motion, removes it from the cylinder. The film of fiber is of the same width as the cylinder of the carding-machine, but it is gathered together by the operator, who passes it through a smooth metal ring, and between two small polished rollers, the revolutions of which carry it forward and deposit it in a deep tin can in the form of a loose untwisted column of cotton or wool, about an inch in thickness, which is called a sliver. A small portion of this arrange ment is shown in fig. 2, which represents a carding-machine with only two carded cylinders, a and b; they are, how ever, much more numerous. There is also a concave iliece of carding, c, which was formerly much used, but has lately given way to additional cylinders, but it makes the action more apparent in 'a drawing; d is the lap drawn on by the action of the twd small rollers e, e, which slightly press it as they revolve. It is quickly distributed all over the surface of the large cylinder a by means of its numerous wire-teeth; and as it passes the roller b, the teeth` of which move in an opposite direction, as indicated by the arrows, the fibers are caught off the large, and are carried round the small cylinder until they reach f, where they are stripped off by the darer g, and are passed through the ring 71, and the rollers i, i, into the tin receiver k. The sliver is now in the first stage of spinning; it has next to be drawn out very gradually until it is not thicker than a quill; and, in drawing it out, the operator gives it a very slight twist, still leaving it so loose in structure that it will break with a slight touch; in this state it is called a roving; and it was at this stage that the spinning-jenny began to operate upon it. The rovings, which were wound as they were drawn upon large reels, were unwound by the machine, and were still further drawn out and firmly twisted and wound on to spindles or cops, the drawing being regu lated by the pressure of the wooden bars of the jenny, which was within reach of the operator's hand.
The throstle-machine, patented by Arkwright in 1769, had for its object the drawing of the rovings through a succession of pairs of rollers, each pair in advance of the others, and moving at different rates of speed. The first pair receive the sliver, compress it, and pass it on to the second pair, which revolve at a greater speed, and thus pull it out to exactly the number of times greater length that their revolutions exceed those of the other pair—in number it is usually'eight times—and as the first roving is passed through a second, third, and sometimes fourth machine, the finished roving is 32 times longer than the sliver. As the roving issues through the last rollers of elIch machine it is received on spools or reels, calculated to hold a given quantity; and these are transferred to the which resemble the roving frames. Here the roving takes the place of the sliver; and, as it unwinds from the spool, is drawn through successive pairs of rollers, moving as before at different rates, each succeeding pair faster than the back ward ones, so tlmat the roving gets thinner and thinner, until the tenuity is carried as far as desiderable. It is then carried on to a spindle which revolves with great rapidity; and, by means of a simple arrangement, is made both to twist the thread and wind it on the spindle ready for the weaver.
This system produces too great a strain upon the thread in its progress to admit of its being drawn so fine as is wanted for many purposes, and this led to the invention of the mule jenny by Crompton (q.v.) in 1779, which has a traveling frame upon which the spindles are set. This frame is now made long enough to carry hundreds of spindles, and it gently draws out and twists the thread after it leaves the last pair of rollers; and when it has reached its limits—now several yards, but in Crompton's time only five feet —it rapidly returns, winding up the spun thread on the spindles as it goes back. These machines are now applied, with various necessary modifications, to cotton, wool, flax, silk, and other textile materials, and the effect they have exerted upon our manufactures is more wonderful than anything in the whole history of commerce. Previous to the inven tion of the mule, few spinners could make yarn of 200 hanks to the pound (the hank being always 840 yards). At the same time, the natives of India were weaving yarn of numbers ranging between 300and 400. Now, however, our manufacturers have reached such extra ordinary perfection, that Messrs. Houldsworth of Manchester have succeeded in making No. 700, which was woven by time French firm Messrs. Thivel & Michou of Tavare, and others far too fine to weave, the greatest tenuity reached being 10,000, a pound of which would reach 4,770 miles. This was made to test the perfection of the machinery, but was of no practical value.
The most modern improvements in spinning are in the machines of Messrs. Platt & Co., of Oldham, which combine all the operations of carding, roving, and spinning in one machine. These and similar machines are now coming into almost universal use for cotton and wool.