Dimensions of engines: Diameter of cylinders, 73-1/2 in.; length of stroke, 7 ft.; weight of engines, wheels, etc., 310 tons; number of boilers, 4; weight of boilers, 90 tons; weight of water in boilers, 80 tons; diameter of wheel, 28 ft. 9 in.; width of floats, 10 ft. Her engines (side-lever) were built by the great firm of Maudslay & Field, who had been for some time one of the most notable marine-engine building firms of the period in Great Britain. They had, up to 1836, built 66 engines for steamers; the first being in 1815, when they built those of the Richmond, of 17 horse-power. The indicated power of the Great Western was 750; and a notable measure of the stride which steam has taken in the half-century since they undertook this contract is that they have since constructed twin-screw engines from which they have guaranteed to produce 19,500 horse-power. These drive a great armor-clad, which has six times the displacement of the Great Western and twice her ordinary speed. The Great Western was launched on July 19, 1837, and was towed from Bristol to the Thames to receive her machinery, where she was the wonder of London. She left for Bristol on March 31, 1838; and arrived, after having had a serious fire on board, on April 2d. In the meantime others had been struck with the possibility of steaming to New York; and a company, of which the moving spirit was Mr. J. Laird, of Birkenhead, purchased the Sirius, of 700 tons, employed between London and Cork, and prepared her for a voyage to New York. The completion of the Great Western was consequently hastened; and she left Bristol on Sunday, April 8, 1838, at 10 A.M. with 7 passengers on board, and reached New York on Monday, the 23d, the afternoon of the same day with the Sirius, which had left Cork Harbor (where she had touched en route from London) four days before the Great Western had left Bristol. The latter still had nearly 200 tons of coal, of the total of 800, on board on arrival; the Sirius had consumed her whole supply, and was barely able to make harbor. [Illustration: Cross-section of the Great Western.]