498 C T T N spindles, the largest number it had till then contained ; for, with the assistance of the above mechanical im provement, the spinner could manage two mules of 300 or 400 spindles each. The process of mule spinning continued to be conducted upon this plan till several proprietors of large cotton works restored the part of Kelly s machinery which returns the carriage irto its place after the draught is completed, thus further lessening the fatigue to the spinner. All that is to be done by the spinner in this case is, with a slight touch of the hand, to shift the belt, so as to allow the carriage to be moved back into its resting position, and, as this takes place, to manage the guide for building the cop, regulate the motion of the carriage as it recedes, and govern the speed of the spindle for winding on the yarn. Some improvements were from time to time made in the headstocks, which either rendered the mule more automatic or else enabled the spinner to work a larger pair of machines ; but notwithstanding the work still required the greatest attention and care, as well as an amount of skill that could only be attained by long practice. Spinners thus became a very important and powerful class, demand ing and obtaining a high rate of wages, and sometimes occasioning to their employers more trouble than any other class. This, doubtless, contributed to the introduc tion of the self-acting mule. At the same time, it must be observed that great improvements were introduced, and still continue to be made, in the construction of the hand mule, perfecting and extending its operative powers, and enabling it to do its t.ork almost automatically with the aid of the most delicate control of the spinner, who has no longer to use his strength to drive the various parts, but is required chiefly to regulate or reduce the velocity of the backing off and winding on, though the same unre mitting attention and care are as necessary as before. The hand mule, as it is designated, is therefore quite as complex a machine as the modern self-acting mule. SELF-ACTING MULE (fig. 14), In 1818 William Eaton obtained a patent for a self-acting mule, in which the opera tions ordinarily performed by the spinner were effected by automatic means, and this machine, though not exten sively adopted, contained several ingenious arrangements Fro. 14. Self-acting Mule. His faller lock, after a lapse of thirty-six years, was said to be re-invented, and still continues to be the best in use at the present day. His apparatus for governing the formation of the cop was founded on correct principles, and was a beautiful contrivance, much superior to many that have been since introduced. Mr Smith of Deanston, Scotland, was also the author of several valuable inven tions, and others might be named who made efforts, more or less successful, to provide the desired machine. About 1824 Richard Roberts directed his attention to the best means of rendering the hand mule self-acting, and in 1825 a patent was taken out for his invention. In the mule now introduced the governing power was exercised by what was then and has ever since been called a " cam shaft," by which all the movements were so regulated as to succeed each other in their proper order, the termination of one operation being the initiation of the next. In 1830 Roberts took out another patent for his "quadrant" winding apparatus, and thus completed his self-acting mule, which in its chief essential features remains the same at the present day; for though as regards the headstock there have been improvements, yet the whole combination still bears indelible marks of his genius. Many improvements have of late years been introduced and patented, and the self-acting mule now in use is superior in its manner of working to the one made by Roberts. It is now employed for spinning all sizes of yarns up to 100 s and in a few cases as high as 160 s, and in the manufacture of these numbers a great saving is effected by its use. It has now almost entirely superseded the hand mule, which only retains its position for the pro duction of the finest yarns, and in a few years will un doubtedly have to give place altogether to the self-actor, on which yarn up to 160 s, or even 200 s, has already been successfully spun. 1 Effects of Machinery, &c., on Production and Cost. About the year 1790 the average product of yarn No. 1C was little more than a hank per spindle per day ; but 1 Fuller details of cotton machinery may be found in a work entitled the Science of Modern Cotton Spinning, <tc., by Evan Leigh, C.E. ; in a paper by Mr John Platt, on machinery for the preparing and spinning of cotton, published in The Proceedings of the Institution
of Mechanical Engineers; and in Spon s Dictionary of Engineering.