The most probable, and at the same time one of the most important of the foregoing proposals, is that designed to connect the Forth with the Clyde, thereby enabling vessels of considerable tonnage to pass from the one sea to the other, without passing round the further extremity of the island. There is already a canal between the two seas, but this waterway is too contracted to be of much use for vessels of any size, and it is not, therefore, proposed to utilise the existing canal in the new scheme. The greatest height of the present canal is 141 feet. It is crossed by about 30 drawbridges, and passes over 10 considerable aqueducts, and 30 small ones, the largest being that over the Kelvin, at Maryhill, near Glasgow. The canal is supplied with water from eight reservoirs, which cover 721 acres. The original cost of the canal was about 300,000_l._, and 50 years after its opening the annual revenue amounted to about 100,000_l._, and the expenditure to about 40,000_l._ In 1869, the canal passed into the possession of the Caledonian Railway Company, when, with the adjoining Monkland Canal, it was valued at 1,141,000_l._ The Caledonian Company undertook to pay an annuity of 91,333_l._, being a guaranteed dividend of six and a quarter per cent. It was, however, like many other similar arrangements made by railway companies in Great Britain, a very bad bargain for the new proprietors, since the profits from the working of the canal are now much less than they were. Messrs. Stevenson, of Edinburgh, who have been consulted as to the most practicable route for the proposed canal, have recommended that the canal proper should begin at Alloa on the Forth, where vessels would be raised by a lock to the level of Loch Lomond, 13 feet above high water, which would be the summit level of the canal. The canal would proceed thence along the valley of the Forth to Loch Lomond, through that loch to Tarbet, and would afterwards be carried along the narrow neck of land to Loch Long, or, alternatively, across to the opposite shore of Loch Lomond, near Arden, and thence into the Forth of Clyde, near Helensburgh. The average depth of cutting is stated at 47 feet, but there would be a heavy cutting, some three miles long and 203 feet deep on an average, which the engineers propose to make a tunnel, with 150 feet of headway. The estimated cost of the work is about 8,000,000_l._, or much the same as the cost of the Manchester Ship Canal. The traffic is calculated at 9,516,000 tons, and it is estimated that at 1_s._ 6_d._ per ton, this traffic would yield a gross annual income of 713,748_l._ which would be sufficient to yield 8 per cent. after deducting working expenses, &c. It is proposed to make the canal 30 feet deep, and 72 feet wide at the bottom.