With the launching of the _Rotomahana_, an ocean steel steamer of 1777 tons gross built by W. Denny and Bros. in 1879 for the Union Steamship Company of New Zealand, the iron age of the steamer may be said to close and the age of steel to begin. It has been shown how iron slowly but surely replaced wood in construction; when the superiority of steel to either had been practically demonstrated the change from iron to steel was rapid. In 1891 over 80 per cent. of the steam-ships under construction were of steel. The _Rotomahana_ was followed in 1881 in the transatlantic trade by the Allan liner _Buenos Ayrean_. The Allan Line has always been to the fore in the provision of first-class steamers. They were the first to have a steel ocean steamer; the first to adopt bilge keels on vessels, the _Parisian_ in 1884 being fitted with them; and they were the first to make the experiment with turbine-driven steamers for ocean traffic in the _Victorian_ and _Virginian_ in 1903. These two vessels are 540 feet in length by 60 feet in breadth, and 40 feet 6 inches in depth. They are of 12,000 tons register, and have a speed of 17 knots. Besides these, the company has five twin-screw boats of tonnages ranging from 9000 to 11,000 tons, and twenty-two screw boats from 3000 to 5395 tons. The Cunard Line’s first steel steamer was the _Servia_, built by Messrs. J. and G. Thomson, and completed in 1881. She was 515 feet in length, and of 7392 gross tonnage, and her engines, of 10,000 indicated horse-power, gave her a speed of 17 knots. Incandescent electric lamps were fitted in her, she being the first of the fleet to carry them. The _Aurania_, of slightly less length, but of equal speed, and also of steel, was built in 1883. After her came the _Umbria_ and _Etruria_, steel single-screw steamers, with engines of 14,500 indicated horse-power, giving them a speed of 20 knots. The sisters _Campania_ and _Lucania_, steel twin-screw vessels of 12,952 tons, were added for the New York trade, and later the _Caronia_ and _Carmania_. They were sisters except in their engines; the latter being the company’s first turbine experiment, and having triple propellers. They are each 675 feet in length by 72 feet 6 inches beam, and 43 feet 9 inches moulded depth.