These creels contain the tubes or bobbins, holding the supply of the attenuated strand of cotton ; the bobbins are arranged vertirally, and held in a position to revolve easily, by lance-wood pegs, called " creel-pegs." In the slubbing-frame, are four pairs of drawing rollers ; but in the roving frame, only three pairs. The number of these rollers is sufficient to extend across the length of the frames from c to c', and are laid horizontally, parallel to each other. The under one of each pair is fluted ; the upper is plain, and covered with leather. The top rollers are generally made with loose bosses, the invention of the late Evan Leigh. Metallic plates, called " caps," cover the rollers, and serve to protect them from dust, and accidental injury. The rollers are mounted on a beam, called the " roller-beam," about midway between the creel and the spindles. The latter constitute a prominent portion of the machine, and are arranged in two rows, one behind the other, as seen at d. They are furnished with fliers, screwed upon the top ; each of them possesses what is termed a " pressure.finger " e. The arnas of the flier, to one of which this is attached, are tubular, and the pressure-finger is interchangeable. It is of great importance, in ensuring the perfeot working and durability of the machine, that the flier should be nicely adjusted upon the spindle, and the arms be in equipoise. Two shafts extend throughout the length of the machine, under each of the series of plates marked f f' and g g'. The lower one carries the bevel wheels, that gear into smaller ones upon the spindles, by which the latter are driven. Similar gearing, upon the corresponding upper shaft, drives the bobbin at a slower speed, and in connection with a differential motion, arranged to accelerate or reduce the pace, a.s the diameter of the bobbin increases by the addition of successive layers of the strand of cotton, and according to the principle on which the machine may have been arranged :—viz. whether the flier runs faster than the bobbin, or the converse.
The formation of the raw material into a strand, and its attenuation, commenced in the carding engine, where the sliver coming from the card is usually about hanks to the pound ; after its passage through the drawing, slubbing, intermediate, and roving frames, it may have became, according te requirement, 5, 7i, or 12 hanks. Should the jack frame be in use, it may be any number of hanks up to 40. The roving is now passed to the last machine of tbe series, in which the processes necessary to the conetruction of a thread from the raw material are completed. This is the mule, throstle, or its modification, the ring frame.
Spinning.—This is the chief process of the series ; those previously described being subordinate and preparatory only. There are two methods in use : the older being that which Arkwright, if he did not invent, certainly rendered practicable, in his " water-frame," which, under subsequent modifications and improvements, has come to be oalled the " throstle-frame "; the second, the mule, invented by Samuel Crompton, in which the chief features of Hargreaves' " jenny " and Arkwright's water-frame are combined. In Hargreaves' machine, which was the first practically
successful attempt to spin more than one thread at a time, a portion of roving was delivered from the frame, and attenuated by the draught of a receding carriage, containing the spindles, which, as they drew out the fibre, gave it the amount of twist necessary to constitute a thread. In all spinning machines, the twine imparted by the spindles naturally crowds into the thinnest portion of the strand, making it firm and hard, but leaving the thick parts almost unchanged. In this state, as the carriage receded still further, the thiek parts of the thread were easily attenuated to the same degree as the other portion, a.nd properly twisted, making a fairly uniform and even thread. This was a far more successful imitation of the operations of the hand spinner than was Ark wright's plan, invented eubsequently ; but it was not nearly so successful, owing to the roving having to be reduced entirely by the stretch of the receding carriage. The attenuation of the roving by the drawing rollers of Arkwright was much more easily accomplished, a.nd admitted of the process of spinning being. continuous ; whilst in the latter, it was intermittent, stopping to vvind npon the spindle each " draw " or length of yam as it was spun, thus consuming nearly of the time. The yarn was also insufficiently twisted for warp purposes, and WM fit only for weft. That produced on the water-frame was firm and hard, and quickly began to displace t he linen warps at that time in use. It had, however, numerous defects, the chief of which was its irregularity in strength and evenness. The crude manner in which the preparatory processes were carried on at that time yielded a very irregular roving, from which the yarn had to be spun. Ark wright's machine possessed no means by which this could be eliminated, the drawing rollers reducing the thick and fine places only in equal proportion. The need of further improvement was therefore generally felt. Amongst the number who sought to accomplish this, was Samuel Crompton, who had been accustomed to spin weft on Hargreaves' jenny. Experience had made him acquainted with the merits and defects of both Hargreaves' and Arkwright's machines, and shown him that, to a great extent, they were complements of each other, and united would almost perfect the art of spinning. This he laboured for a long time to realize, and the fruit of his efforts was the mule, in which the distinctive features of the jenny and the water-frame are c,ombined : the stretch of the yam in the former, and the attenuation of the roving by means of rollers in the latter. The result of his success was quickly seen in the rapid multiplication of spindles chiefly on this principle. With subsequent improvements, the mule has become the most perfect and important machine in the series, and, as mch, claims priority of notice.