All About Engines

276 All About Engines The successes of Fulton and Bell naturally led to an enormous development. In 1814 there were only five steamers in Great Britain, in 1820 there were 34, and in 1840 there were 1,325- By that time the Atlantic had been crossed by vessels depend- ing entirely upon steam, and the first regular trans- atlantic service had been established. The ships were still of wood, and were provided with paddle- wheels. Iron ships came in about 1850, and the screw propeller began to displace paddle wheels about ten years later. In the eighties large vessels were fitted with twin screws, and with the dawn of the twentieth century the largest vessels were propelled by triple screws. One of the marvels of the nineteenth century was the Great Eastern, built by the brilliant but, in some respects, unfortunate engineer Brunel, and launched in 1858. This huge vessel was 692 feet long, 83 feet beam, 60 feet deep, and displaced 24,000 tons. She was propelled by both a screw and paddle wheels. The latter were 56 feet in diameter, and the screw was 24 feet. Four engines were required for each. The cylinders were 6 feet 2 inches in diameter, and steam was supplied by ten boilers with seventy-two furnaces. The horse-power was 8,000. In size these engines compare very favourably with those of modern ships, but they are far inferior to them in power. Thus the Olympic has not ten, but twenty-nine boilers, each weighing not 50, but 105, tons ; and while the Great Eastern consumed only about 300 tons of coal per twenty-four hours the