But wool was the staple of England. Parliament and people were jealous of cotton, lest it might prove a rival to wool, and actually prohibited the introduction of printed calicoes (so called from Calicut in India whence they were exported). The taste, however, for calicoes increased in spite of the prohibition, which was afterwards intermitted for a revenue duty on plain cotton, which was then rudely printed on blocks in London, Manchester, and elsewhere; but the prohibition of Parliament against wearing printed calicoes was first repealed in 1736. Fifteen years later the United Kingdom imported only 2,976,610 lbs. of raw cotton, and exported only £45,986 of cotton goods; in one century the import of cotton became 500 times larger than that, and the export of cottons 1300 times larger than that; and this prodigious result was due mainly to three or four inventions occurring within short times of each other, by means of which the free forces of nature took the place of the onerous efforts of men. John Hargreaves, a poor weaver in the neighborhood of Blackburn in Lancashire, was returning home from a long walk, in which he had been purchasing a further supply of yarn for his own loom. Spinning at that time only admitted of one thread spun at a time by one pair of hands, one of which turned the wheel and thus made the single spindle rapidly revolve, and the other hand pulled gently upon the "roving" attached to the spindle and thus drew it out to the requisite tenuity twisted into yarn. The "carding," then effected by rude instruments called hand-cards, by means of which the fibres of the cotton were disentangled and straightened and laid parallel with each other; and the "roving," a process by which the short fleecy rolls stripped off the hand-cards were applied to the spindle and made into thick threads only slightly twisted, were the two preparatory operations for the spinning. All these operations were slow and clumsy, and the consequent expensiveness of the yarn formed a great obstacle to the establishment of the cotton manufacture in England. The improvements made in the loom of that period by Kay, father and son, had shortly before doubled the power of each weaver, and the spinners could not keep up in furnishing material to the weavers.