Nor did historians perceive that the world-famous wars in which England was engaged at the close of the last century and up to 1815, were necessitated by England’s endeavour to gain the commercial supremacy of the world, after she had invented the means of supplying the world’s markets to overflowing. Economic causes were at the root of them all. We shall discuss later the connection between our foreign politics and our industry; at present we must adhere to the subject of the development of that industry by the great inventors.[46] {159} [46. There was an Agricultural Revolution as important as the Industrial one, but it is best to treat it separately. I have done so in Ch. vi.] § 2. THE GREAT INVENTORS--The transition from the domestic to the factory system was begun by four great inventions. In 1770 James Hargreaves, a weaver of Standhill, near Blackburn, patented the spinning-jenny--_i.e._ a frame with a number of spindles side by side, which were fed by machinery, and by which many threads might be spun at once, instead of only one, as had been the case in the old one-thread hand-spinning wheel. Hargreaves first used this “jenny” for some time in his own house, and was at once enabled to spin eight times as much yarn as before. In 1771 Arkwright established a successful mill at Cromford on the Derwent, in which he employed his patent spinning machine, or “water-frame,” an improvement upon a former invention of Wyatt’s, which derived its name from the fact that it was worked by water power. A few years later (1779) both these inventions were superseded by that of Samuel Crompton, a spinner, but the son of a farmer near Bolton. His machine, the “mule,” combined the principles of both the previous inventions, and was called by this name as being the hybrid offspring of its mechanical predecessors. It drew out the roving (_i.e._ the raw material when it has received its first twist) by an adaptation of the water-frame, and then passed it on to be finished and twisted into complete yarn by an adaptation of the spinning-jenny. This invention effected an enormous increase in production, for nowadays 12,000 spindles are often worked by it at once and by one spinner. It dates from the year 1779, and was so successful that by 1811 more than four and a half million spindles worked by “mules” were in use in various English factories. Like many inventors Crompton died in poverty in 1827.