HKB
the scale-beam (by which, with a load of 2 oz. on each end, the fifteen-hundredth part of a grain could be indicated), in the broaching-machine, the slotting-machine, and other engines.
But the inventions by which his fame became most extensively known arose out of circumstances connected with the cotton manufactures of Manchester and the neighbourhood. The great improvements which he introduced in the machine for making weavers' reeds, led to the formation of the firm of Sharp, Roberts, and Co., of which Mr. Roberts was the acting mechanical partner for many years. Not less important were his improvements in power-looms for weaving fustians, which were extensively adopted. But by far the most famous of his inventions was unquestionably his Self-acting Mule, one of the most elaborate and beautiful pieces of machinery ever contrived. Before its invention, the working of the entire machinery of the cotton-mill, as well as the employment of the piecers, cleaners, and other classes of operatives, depended upon the spinners, who, though receiving the highest rates of pay, were by much the most given to strikes; and they were frequently accustomed to turn out in times when trade was brisk, thereby bringing the whole operations of the manufactories to a standstill, and throwing all the other operatives out of employment. A long-continued strike of this sort took place in 1824, when the idea occurred to the masters that it might be possible to make the spinning-mules run out and in at the proper speed by means of self-acting machinery, and thus render them in some measure independent of the more refractory class of their workmen. It seemed, however, to be so very difficult a problem, that they were by no means sanguine of success in its solution. Some time passed before they could find any mechanic willing so much as to consider the subject. Mr. Ashton of Staley-bridge made every effort with this object, but the answer he got was uniformly the same. The thing was declared to be impracticable and impossible. Mr. Ashton, accompanied by two other leading spinners, called on Sharp, Roberts, and Co., to seek an interview with Mr. Roberts. They introduced the subject to him, but he would scarcely listen to their explanations, cutting them short with the remark that he knew nothing whatever about cotton-spinning. They insisted, nevertheless, on explaining to him what they required, but they went away without being able to obtain from him any promise of assistance in bringing out the required machine.
The strike continued, and the manufacturers again called upon Mr. Roberts, but with no better result. A third time they called and appealed to Mr. Sharp, the capitalist of the firm, who promised to use his best endeavours to induce his mechanical partner to take the matter in hand. But Mr. Roberts, notwithstanding his reticence, had been occupied in carefully pondering the subject since Mr. Ashton's first interview with him. The very difficulty of the problem to be solved had tempted him boldly to grapple with it, though he would not hold out the slightest expectation to the cotton-spinners of his being able to help them in their emergency until he saw his way perfectly clear. That time had now come; and when Mr. Sharp introduced the subject, he said he had turned the matter over and thought he could construct the required self-acting machinery. It was arranged that he should proceed with it at once, and after a close study of four months he brought out the machine now so extensively known as the self-acting mule. The invention was patented in 1825, and was perfected by subsequent additions, which were also patented.