Two machines, two limits
By the late 1770s, British spinners had two important machines, and each had a shortcoming. The spinning jenny made soft thread in quantity, but the thread was not strong. The water frame, with its rollers, made hard, strong thread, but it was coarse and could not make the very fine yarns that delicate cloth required. A machine that joined the advantages of both was an obvious goal, and several people were working in that direction.
Samuel Crompton’s mule
Samuel Crompton was a spinner and weaver from near Bolton in Lancashire. Working at his home, Hall i’ th’ Wood, he spent years building a new machine, which he completed around 1779. It became known as the mule because it was a hybrid, taking its main features from the two earlier machines. The name was in use by the 1780s.
From the water frame, the mule took sets of rollers that drew out the roving to the right thickness. From the jenny, it took a moving carriage that held the spindles and slid away from the rollers and back again. In outline, a cycle looked like this:
- The rollers delivered a length of roving while the carriage moved away from them.
- The carriage moved slightly faster than the rollers, which stretched the thread and made it finer and more even.
- The spindles turned, putting twist into the thread as it was drawn.
- At the end of the stretch, the spindles wound the finished length onto the yarn package as the carriage was pushed back.
Because the thread was supported and stretched gently while it was twisted, the mule could make yarn that was both strong and fine. It could spin a wide range of counts, from fairly coarse to very fine, and the best mule-spun yarns allowed cotton muslins of a delicacy that British makers could not previously match. Muslin had been a specialty of Indian weavers, and British fine cotton goods increasingly competed with imports.
The inventor who gained little
Crompton did not patent the mule. Accounts say he feared he could not afford the cost or was worried about sharing the design, and that he was pressed to reveal the working to manufacturers who had begun to copy it. He agreed to a public subscription, in which manufacturers pledged payments in exchange for details. The sum he raised was modest, and many who pledged did not pay. In 1812, Parliament awarded him a grant of 5,000 pounds, which was much less than the value of the machine to the industry. He attempted other business ventures with limited success, and died in 1827.
Growth and the self-acting mule
Early mules were small and operated by hand, with the spinner pushing the carriage in and out and turning the handle. Over time, mules grew in size, with hundreds of spindles, and were adapted for water or steam power. Large mills had long rooms with rows of mules, each facing another, in which the carriages ran out over the floor and back again.
Early on, the power drove only the spindles and rollers, while the spinner still moved the carriage by hand and judged the right tension at each stage. Efforts to make the whole cycle automatic came after 1790. The key advance was the “self-acting” mule, patented by Richard Roberts of Manchester in 1825 and refined in the following years. It used the engine to run the carriage out and in, control the spindle speed and wind the thread onto the yarn package, with the operator mostly watching for breaks and joining ends. Roberts’ design is often mentioned with his work on the power loom and his later machine tools.
Mule spinning was among the most skilled work in the cotton mills. In many places the senior spinners were men, supported by young assistants known as piecers, who joined broken threads, and scavengers, who cleaned beneath the machines. The skill of the spinner was valuable, and unions of mule spinners became some of the strongest labor organizations in the industry. The self-acting mule was partly welcomed by owners as a means of reducing the leverage of those skilled workers, and conflicts over it were common.
Why it lasted
The mule remained in use for well over a century. It could make a wider range of yarn than competing systems, and it was especially favored for fine counts. Ring spinning, developed in the United States in the early 1800s and improved through the century, was faster and needed less skill, so it gradually took over for many yarns, especially in the 1900s. Even so, mules were still running in some mills into the later 1900s.
Significance
With the mule, Britain could spin cotton yarn finer, cheaper and in greater quantity than before, and the mill owners who adopted it were able to supply the weaving trade. This helped drive demand for power looms and, indirectly, for raw cotton, which the cotton gin made cheaper to process in the United States. Because mills with heavy machines needed reliable energy, mule spinning also contributed to the spread of steam engines in factories. In the broader textile industry, the mule shows how the strengths of separate ideas could be combined to remove the limits that each one had on its own.