Other ocean steamship companies gradually arose, some of which are still in existence. But no especial change in ship-building was introduced until 1870, when the Oceanic Company, now known as the White Star Line, built the Britannic and Germanic. These were the largest of its early ships. They were 468 feet long and 35 feet wide, constituting a new type of extreme length as compared with their width. In the first White Star ship, the Oceanic, the improvements above mentioned were introduced, the saloons and staterooms being brought as near as possible to the center of the ship. All the principal lines built since that date have followed this example, thus adding much to the comfort of the first-class passengers. Speed and economy in power also became features of importance, the tubular boiler and the compound engine being introduced. These have developed into the cylindrical, multitubular boiler and the triple expansion engine, in which a greater percentage of the power of the steam is utilized and four or five times the work obtained from coal over that of the old system. The side-wheel was continued in use in the older ships until this period, but after 1870 it disappeared. It has been said that the life of iron ships, barring disasters at sea, is unlimited, that they cannot wear out. This statement has not been tested, but the fact remains that the older passenger ships have gone out of service and that steel has now taken the place of iron, as lighter and more durable. Something should also be said here of the steam turbine engine, recently introduced in some of the greatest liners, and of proven value in several particulars, an important one of these being the doing away with the vibration, an inseparable accompaniment of the old style engines. The Olympic and Titanic engines were a combination of the turbine and reciprocating types. In regard to the driving power, one of the recent introductions is that of the multiple propeller. The twin screw was first applied in the City of New York, of the Inman line, and enabled her to make in 1890 an average speed of a little over six days from New York to Queenstown. The best record up to October, 1891, was that of the Teutonic, of five days, sixteen hours, and thirty minutes. Triple-screw propellers have since then been introduced in some of the greater ships, and the record speed has been cut down to the four days and ten hours of the Lusitania in 1908 and the four days, six hours and forty-one minutes of the Mauretania in 1910. The Titanic was not built especially for speed, but in every other way she was the master product of the shipbuilders' art. Progress through the centuries has been steady, and perhaps the twentieth century will prepare a vessel that will be unsinkable as well as magnificent. Until the fatal accident the Titanic and Olympic were considered the last words on ship-building; but much may still remain to be spoken. CHAPTER XXVII. SAFETY AND LIFE-SAVING DEVICES