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THREE:[See larger version]The next step in the increase of means of traffic was the construction of canals. The rivers had previously been rendered more navigable by removing obstructions, deepening channels, and making good towing-paths along their banks; but now it was projected to make artificial rivers. In this scheme, Richard Brindley, under the patronage of the Duke of Bridgewater, was the great engineer; and his intrepid genius dictated to him to carry these canals over hills by locks, over rivers by aqueducts, and through the heart of hills by tunnels. These enterprises at that moment appeared, to the ordinary run of civil engineers, as rash experiments, which were sure to prove abortive. As all new ideas are, these ideas, now so commonplace, were ridiculed by the wise ones as little short of madness. Mr. Brindley's first great work was the formation of the Duke of Bridgewater's canal, from Worsley to Manchester. In this he at once proved all his plans of locks, tunnels, and aqueducts. He conducted his canal by an aqueduct over the river Irwell, at an elevation of thirty-nine feet; and those learned engineers who had laughed at the scheme as "a castle in the air," might now see boats passing over the river at that height with the greatest ease, while other boats were being drawn up the Irwell against the stream and under the aqueduct with five times the labour. At Worsley the canal was conducted into the very heart of the coal-mine by a tunnel, with branches, which conducted the boats up to the different parts of the[191] mine, so that the coal could be loaded on the spot where it was dug. The immediate effect of this canal was to reduce coals in Manchester to half the former price; and the canal being extended so as to connect it with the Mersey, at Runcorn, it reduced the freight of goods from Manchester to Liverpool to the same extent, from twelve shillings to six shillings per ton, the land carriage having been forty shillings. Brindley was next engaged to execute the Grand Trunk Canal, which united the Trent and Mersey, carrying it through Birmingham, Chesterfield, and to Nottingham. This was commenced in 1766, and exhibited further examples of his undaunted skill, and, as he had been laughed at by the pedants of the profession, he now in his turn laughed at their puny mediocrity. One of his tunnels, at Harecastle Hill, in Staffordshire, was two thousand eight hundred and eighty yards long, twelve feet wide, nine high, and in some parts seventy yards below the surface of the ground. This tunnel, after half a century's use, was found too confined for the traffic, and a new one, much wider, was made by Telford. By this time the art of tunnelling had made great progress, and whilst Brindley required eleven years to complete his tunnel, Telford made his much larger one in three. Many causes intervened to check for a time the progress of canals, so that from 1760 to 1774 only nineteen Acts were passed for them; but in the two years of 1793 and 1794 no fewer than thirty-six new Bills were introduced to Parliament, with others for extending and amending rivers, making altogether forty-seven Acts, the expenditure on the canals of these two years' projection amounting to five million three hundred thousand pounds. The work now went on rapidly, and investments in canal shares exhibited at that day, in miniature, the great fever of railway speculation at a later period. Lines of canals were made to connect the Thames, the Tweed, the Severn, and the Mersey; so that the great ports of London, Liverpool, Hull, and Bristol were connected by them, and put into communication with nearly all the great inland manufacturing towns. In 1779 a ship-canal was completed from the Forth to the Clyde��a work proposed as early as the reign of Charles II. This canal, thirty-five miles in length, had thirty-nine locks, which carried the canal to a height of one hundred and fifty-six feet above the sea, and it crossed the river Kelvin by an aqueduct eighty-three feet from the bed of the river to the top of the masonry. A few years later a much larger ship-canal united Gloucester to the Severn, and wonderfully increased the trade and growth of that city.