Page:Encyclopædia Britannica, Ninth Edition, v. 6.djvu/529

Rh 497 40 could not without the combing machine be spun to advantage. Since the introduction of the latter, throstles have been constructed to spin yarns as fine as Nos. 80 or 100. The reason is that the fine thread has not strength to stand the drag required for winding the yarn upon the bobbin, ^the difficulty being occasioned by each thread having its own drag regulated separately. In Oompton s mule and Hargreaves s jenny this difficulty was avoided by the spinner putting the required tension or drag on the yarn by the &quot; faller,&quot; which operating on all the threads at once, and being controlled by the hand of the spinner, allowed the tension of the yarn during the winding on to be easily governed. All wefts, from the lowest to the highest num bers, are now spun upon Crompton s machine, the use of Hargreaves s jenny having been almost entirely superseded by it as regards cotton, though not as regards woollen. It was some time, indeed, after the mule came into use before it was ascertained that the finest yarn required for the manufacture could be produced from it. But in the year 1792, Jonathan Pollard of Manchester succeeded in spinning yarn of 278 hanks to the pound, from cotton wool grown by Mr Robley, in the island of Tobago. This yarn was sold at twenty guineas per pound to the muslin manufacturers of Glasgow. The mule, in its structure and operation, is a compound of the spinning frame and of Hargreaves s jenny ; from which circumstance it probably received its name. It contains a system of rollers like that belonging to the throstle ; but the attenuated roving, as it issues from between the rollers, is twisted by the action of the spindles, which, in the mule, are mounted on a movable carriage that recedes from the rollers a little faster than the roving is delivered by them. The mode of putting the twist in by means of the spindles is exactly the same as in the jenny, and in fact resembles the most ancient method of using a spinning spindle. When a sufficient length of yarn or a &quot; stretch &quot; had been spun the rollers and spindles were stopped, the yarn coiled round the bare spindles was unwound, or &quot; backed off,&quot; as it is technically called, the faller was putdown by the spinner and the &quot; nose &quot; of the Fia. 13. Hand Mule. cop, and the spindles turned during the run in of the carriage with sufficient quickness to wind the spun yarn on the top of the yarn already wound on the spindles. When the spindle points have been brought by the running in of the carriage within a short distance of the delivery rollers, the rollers and spindles are again set in motion for another stretch. The manner of backing off and winding the spun yarn on the spindles is exactly the same as that used in Hargreaves s jenny. Crompton s great merit con sisted in the adaptation of the best features of the throstle and the best principles of Hargreaves s jenny, so as to obtain from the combination of the two the principal elements of a perfect spinning machine. The motive power being manual, the work was rendered more fatiguing as the mules became longer, and thus the size of the machine was restricted by the strength of the spinner. In spinning the finer counts of yarn it became customary to continue the outward movement of the carriage, and the rotation of the spindles, a short time after the rollers were stopped; the movement of the carriage was then arrested, but the rotation of the epindles continued until the proper amount of twist had been put in the yarn. This last operation resembles that performed by the common jenny, and produces a similar effect. In 1792 William Kelly of Glasgow, at that time manager of the Lanark mills, obtained a patent for moving the mule by power, in order to relieve the spinner of the most laborious part of his work, and thus enable him to attend to a longer mule and spin the yarn at a reduced cost. Kelly s machinery was contrived so as to move every part of the mule, even to the returning of the carriage into its place, after the draught was finished. Had it come into full operation, fewer men need have been employed as spinners, and children would have been able to do a great part of the duty required. But, after a short trial, it was discovered that this invention, though intended to bring out the carriage, and return it again during the winding on of the yarns, was found to be valuable only for bringing out the carriage. A spinner could, however, serve two mules, the one carriage moving out during the time that the other was returning. It was next found unnecessary to confine the mule to 144 VI. 63