Let us enter the engine-room of a big liner, and see for ourselves. It is a triumph of engineering. Still, at first, you cannot understand anything of the complicated mass of machinery. Then you notice three large cylinders—for these are triple-expansion engines—with pistons shooting in and out downwards, and attached by connecting rods to the cranks of the propeller shaft below. The cranks are bent at different angles so that they can never all be in the same position at once. There is a maze of machinery and shining rods, bewildering to the uninitiated eye. But you gradually notice how absolutely regular every part is in its action, and how beautifully one part fits with another. Then go before the furnace; you find yourself in front of a huge structure, at the bottom of which is the long fire box; above rises the heat box communicating with tubes over the furnaces, with the water circulating between. The water, indeed, is beneath the furnace, about parts of the heat box, between and above the tubes. The object is, of course, to obtain as great heating surface as possible. The tubes communicate with the funnel at their other end. Boilers are made of a “mild” steel which has, it is said, a most remarkable tenacity of 28 tons to the square inch. Consequently they are able to bear great pressure of steam. [Illustration: STOKE HOLE.] Hot distilled water is admitted to the boiler from the surface condenser. This is a “box,” riddled with tubes, through which cold sea water is pumped. The waste steam, having done its work in the cylinders, is passed into this “box,” is condensed by touching the chilly tubes of sea water, and can be run off or pumped to a hot cistern, whence it is used to feed the boiler and be turned once more to steam. About 4000 tons of water an hour pass through the surface condensers of a large liner when she is at full work. The largest steamers require over 150 men to work the furnaces and machinery, and the attention given is hard and unremitting. In some of the fast Atlantic greyhounds the strain is terribly severe, especially when the sea is beginning to run high. The rollers may be but 20 feet, yet these are quite high enough even for a splendid ocean racer to contend with and yet maintain her speed. Now her bows are pointing sky high, and her stern is deeply submerged; now she takes a header plump into the trough of the sea, and the engines race round; the propeller is suddenly raised out of water. But blow high, or blow low, on she goes, and the engineers are always busy. The furnaces roar with ceaseless rage. For days and nights the fires are kept at glowing heat. A forced blast maintains the draught; the steam condensed back into warm water is supplied to the boilers; half-naked men work hour after hour to rake the fires, clean them, pile on the fuel, and keep the most powerful head of steam the boilers can stand.