Even after its enlargement, no vessel drawing more than 10 feet of water, or over 150 feet in length, could pass through the Welland Canal. Increased accommodation being needed, a larger canal with a new set of locks was commenced in 1873, and completed in 1881. This canal branches off from the old canal 19 miles from Lake Erie, and rejoins it again at Lake Ontario. The old canal was deepened from Lake Erie to its junction, with the new canal, so that vessels having a draught of less than 12 feet can pass from one lake to the other. The new canal is 100 feet wide at the bottom, 12 feet in depth, and has side slopes of 2 to 1; but the excavation through rock has been carried down to 14 feet in depth, to facilitate the deepening of the canal if required in the future. It is 13 miles long, and cost 3,840,000_l._ The difference in level is 313 feet, which is surmounted by twenty-five locks, with lifts ranging between 12 to 16 feet. Regulating weirs have also been built, some attaining a width of 300 feet; the flow of water through them is regulated by sluice-gates, formed of sheet iron, which are raised and lowered by screws. The locks are 40 feet 4 inches wide, and have a length of 270 feet between the sills. The side walls are 29 feet high, with a batter of 1 in 24; they are built of limestone ashlar, and are strengthened by counterforts. The lock floor is planked with pine timber, and the gates are constructed of white oak. The gates are moved by chains, guided by rollers and winding round drums, and one man is able to move a gate. The sluice-gates are raised by lifting a small shutter (½ foot by 1 foot), which allows the current to work a small turbine, whose revolutions set in motion a screw which raises and lowers the sluice-gate. The rate of motion transmitted by the turbine is so much reduced in passing through a train of wheels and a revolving nut that 212 revolutions of the turbine are required to raise the sluice-gate 1 inch. The sluice-gates are 5 feet by 1½ foot, and are raised in two minutes. It has been doubted by many men who have carefully studied the question whether the very large expenditure that has been incurred over the Welland Canal will ever be justified by the result. The canal is, of course, the main connecting link between the great lakes of the south and south-west and the principal maritime outlets of the Dominion, and the Dominion Government has no doubt been animated by the belief that the time would come when the great commerce that now passes from Duluth, Chicago, and other ports in the United States to New York, and thence to Europe, would take the Welland Canal route, instead of the Erie Canal, thereby making Montreal the chief port on the American continent. This impression has been supported by the consideration that Montreal is nearly 300 miles nearer to Liverpool than New York.