Another of Yarranton's far-sighted schemes of a similar kind was one to connect the Thames with the Severn by means of an artificial cut, at the very place where, more than a century after his death, it was actually carried out by modern engineers. This canal, it appears, was twice surveyed under his direction by his son. He did, however, succeed in his own time in opening up the navigation of the Avon, and was the first to carry barges upon its waters from Tewkesbury to Stratford. The improvement of agriculture, too, had a share of Yarranton's attention. He saw the soil exhausted by long tillage and constantly repeated crops of rye, and he urged that the land should have rest or at least rotation of crop. With this object he introduced clover-seed, and supplied it largely to the farmers of the western counties, who found their land doubled in value by the new method of husbandry, and it shortly became adopted throughout the country. Seeing how commerce was retarded by the small accommodation provided for shipping at the then principal ports, Yarranton next made surveys and planned docks for the city of London; but though he zealously advocated the subject, he found few supporters, and his plans proved fruitless. In this respect he was nearly a hundred and fifty years before his age, and the London importers continued to conduct their shipping business in the crowded tideway of the Thames down even to the beginning of the present century. While carrying on his iron works, it occurred to Yarranton that it would be of great national advantage if the manufacture of tin-plate could be introduced into England. Although the richest tin mines then known existed in this country, the mechanical arts were at so low an ebb that we were almost entirely dependent upon foreigners for the supply of the articles manufactured from the metal. The Saxons were the principal consumers of English tin, and we obtained from them in return nearly the whole of our tin-plates. All attempts made to manufacture them in England had hitherto failed; the beating out of the iron by hammers into laminae sufficiently thin and smooth, and the subsequent distribution and fixing of the film of tin over the surface of the iron, proving difficulties which the English manufacturers were unable to overcome. To master these difficulties the indefatigable Yarranton set himself to work. "Knowing," says he, "the usefulness of tin-plates and the goodness of our metals for that purpose, I did, about sixteen years since (i.e. about 1665), endeavour to find out the way for making thereof; whereupon I acquainted a person of much riches, and one that was very understanding in the iron manufacture, who was pleased to say that he had often designed to get the trade into England, but never could find out the way. Upon which it was agreed that a sum of monies should be advanced by several persons,[13] for the defraying of my charges of travelling to the place where these plates