This conclusion is the outcome of a series of practical experiments conducted on the Shropshire Union Canal at a time when the theorists were still working out their calculations on paper. The experiments in question were directed to ascertaining whether economy could be effected by making up strings of narrow canal boats, and having them drawn by a tug worked by steam or other motive power, instead of employing man and horse for each boat. The plan answered admirably until the locks were reached. There the steam-tug was, temporarily, no longer of any service. It was necessary to keep a horse at every lock, or flight of locks, to get the boats through, so that, apart from the tedious delays (the boats that passed first having to wait for the last-comers before the procession could start again), the increased expense at the locks nullified any saving gained from the mechanical haulage. As a further illustration--drawn this time from Scotland--of the relations of railway companies to canals, I take the case of the Forth and Clyde Navigation, controlled by the Caledonian Railway Company. This navigation really consists of two sections--the Forth and Clyde Navigation, and the Monkland Navigation. The former, authorised in 1768, and opened in 1790, commences at Grangemouth on the Firth of Forth, crosses the country by Falkirk and Kirkintilloch, and terminates at Bowling on the Clyde. It has thirty-nine locks, and at one point has been constructed through 3 miles of hard rock. The original depth of 8 feet was increased to 10 feet in 1814. In addition to the canal proper, the navigation included the harbours of Grangemouth and Bowling, and also the Grangemouth Branch Railway, and the Drumpeller Branch Railway, near Coatbridge. The Monkland Canal, also opened in 1790, was built from Glasgow _viâ_ Coatbridge to Woodhall in Lanarkshire, mainly for the transport of coal from the Lanarkshire coal-fields to Glasgow and elsewhere. Here the depth was 6 feet. The undertakings of the Forth and Clyde and the Monkland Navigations were amalgamated in 1846. Prior to 1865, the Caledonian Railway did not extend further north than Greenhill, about 5 miles south of Falkirk, where it joined the Scottish Central Railway. This undertaking was absorbed by the Caledonian in 1865, and the Caledonian system was thus extended as far north as Perth and Dundee. The further absorption of the Scottish North-Eastern Railway Company, in 1866, led to the extension of the Caledonian system to Aberdeen.