In the textile industry, a spinning mule is a device invented in the 18th century that spun textile fibers into yarn by an intermittent process: in the draw stroke, the roving is pulled through and twisted; on the return, it is wrapped onto the spindle.
Born in 1753 in Lancashire, England, Samuel Compton grew up spinning yarn to help support his family after his father died. He, therefore, became deeply familiar with the limitations of the industrial machinery used to process cotton into yarn.
In 1779, Samuel Crompton invented the spinning mule that combined the moving carriage of the spinning jenny with the rollers of the water frame. The name "mule," in fact, comes from the fact that the machine is a hybrid between the two earlier machines, much the way a mule is a hybrid between a horse and a donkey. Crompton supported his inventing by working as a violinist at the Bolton Theatre for pennies a show, spending all his wages on the development of the spinning mule.
The mule was an important development because it could spin thread better than by hand, which led to every finer threads that commanded a better price in the marketplace. The thin threads spun on the mule sold for at least three times the price of coarser threads. Once perfected, the spinning mule gave the spinner great control over the weaving process, and many different types of yarn could be produced. It was improved upon by William Horrocks, known for his invention of the variable speed button, in 1813.
Many inventors of the 18th century encountered difficulty over their patents. It took Samual Compton more than five years to invent and perfect the spinning mule, but he failed to obtain a patent for his invention. Seizing on the opportunity, the famed industrialist Richard Arkwright did patent the spinning mule.
A British Commons Committee, dealing with Samuel Crompton's patent claims in 1812, said that "the method of reward to an inventor, as generally accepted in the eighteenth century, was that the machine, etc., should be made public and that a subscription should be raised by those interested, as a reward to the inventor."
Such a philosophy may have been practical in the days when inventions required little capital to develop, but it was decidedly inadequate in the time since the industrial revolution when investment money became essential for the production of any great technical improvement. British law of the time was well behind the state of industrial progress.
However, Compton was able to demonstrate the financial harm he had suffered by gathering evidence of all the factories using his invention. More than four million spinning mules were then in use, and Parliament awarded Compton 5,000 pounds. Compton attempted to go into business with these funds but was unsuccessful. He died in 1827.