Meanwhile, the industrial movement did not stop here. Single capitalists began to set up spinning jennies in great buildings and to use water-power for driving them, so placing themselves in a position to diminish the number of workers, and sell their yarn more cheaply than single spinners could do who moved their own machines by hand. There were constant improvements in the jenny, so that machines continually became antiquated, and must be altered or even laid aside; and though the capitalists could hold out by the application of water-power even with the old machinery, for the single spinner this was impossible. And the factory system, the beginning of which was thus made, received a fresh extension in 1767, through the spinning throstle invented by Richard Arkwright, a barber, in Preston, in North Lancashire. After the steam- engine, this is the most important mechanical invention of the 18th century. It was calculated from the beginning for mechanical motive power, and was based upon wholly new principles. By the combination of the peculiarities of the jenny and throstle, Samuel Crompton, of Firwood, Lancashire, contrived the mule in 1785, and as Arkwright invented the carding engine, and preparatory ("slubbing and roving") frames about the same time, the factory system became the prevailing one for the spinning of cotton. By means of trifling modifications these machines were gradually adapted to the spinning of flax, and so to the superseding of hand-work here, too. But even then, the end was not yet. In the closing years of the last century, Dr. Cartwright, a country parson, had invented the power-loom, and about 1804 had so far perfected it, that it could successfully compete with the hand-weaver; and all this machinery was made doubly important by James Watt's steam-engine, invented in 1764, and used for supplying motive power for spinning since 1785.