The turbine has been applied to mercantile as well as warlike purposes. There is at the present time a turbine-propelled steamer, the _King Edward_, running in the Clyde on the Fairlie-Campbelltown route. This vessel, 250 feet long, 30 broad, 18 deep, contains three turbines. In each the steam is expanded fivefold, so that by the time it passes into the condensers it occupies 125 times its boiler volume. (On the _Viper_ the steam entered the turbine through an inlet eight inches in diameter, and left them by an outlet four feet square.) In cylinder engines thirty-fold expansion is considered a high ratio; hence the turbine extracts a great deal more power in proportion from its steam. As a turbine cannot be reversed, special turbines are attached to the two outside of the three propeller shafts to drive the vessel astern. The steamer attained 20-1/2 knots over the “Skelmorlie mile” in fair and calm weather, with 3500 horse-power produced at the turbines. The _King Edward_ is thus the fastest by two or three knots of all the Clyde steamers, as she is the most comfortable. We are assured that as far as the turbines are concerned it is impossible by placing the hand upon the steam-chest to tell whether the drum inside is revolving or not! Every marine engine is judged by its economy in the consumption of coal. Except in times of national peril extra speed produced by an extravagant use of fuel would be severely avoided by all owners and captains of ships. At low speeds the turbine develops less power than cylinders from the same amount of steam, but when working at high velocity it gives at least equal results. A careful record kept by the managers of the Caledonian Steamship Company compares the _King Edward_ with the _Duchess of Hamilton_, a paddle steamer of equal tonnage used on the same route and built by the same firm. The record shows that though the paddle-boat ran a fraction of a mile further for every ton of coal burnt in the furnaces, the _King Edward_ averaged two knots an hour faster, a superiority of speed quite out of proportion to the slight excess of fuel. Were the _Duchess_ driven at 18-1/2 knots instead of 16-1/2 her coal bill would far exceed that of the turbine. As an outcome of these first trials the Caledonian Company are launching a second turbine vessel. Three high-speed turbine yachts are also on the stocks; one of 700 tons, another of 1500 tons, and a third of 170 tons. The last, the property of Colonel M’Calmont, is designed for a speed of twenty-four knots.