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Show ' THE MODERN STEAMSHIP. Impossible to Guess What Speed May No Be Reached Hereafter. Twenty years ago it was thought by many tht the limit as to size, speed and economy had been reached. At present pres-ent it seems that the draft of water at the harbors and the cost are the limits that will prevent further development on present lines. With different material ma-terial for construction, with liquid fuel, and other improvements or inventions, it is possible that 20 years from now one may look back at the Lucania with her 21.6 knots as we look back on th Germanic and Britannio of 1874 with their 16 knots. The steam pressures on ocean steamers steam-ers up to 1850 did not exceed 20 pounds. With the earlier vessels, with only 5 to 10 pounds of steam, it was possible to stop a leak in a boiler "by pushing a vag in the hole." As late a3 1846-a prominent firm of engine builders in England stated that from 10 to 12 pounds was what they used . for merchant mer-chant vessels. By 1880 pressure had increased in-creased to from CO to 90 pounds, and on the introduction of steel for boilers pressures pres-sures went up to about 100 pounds by 1885, and now boilers are being built, for large steamers, to carrv 200 Bounds. Special types of boilers for torpedo boats and other uses carry much higher pressure.- The Ericsson machinery weighs only 66 pounds per horsepower. This last is for torpedo boats and high pressures and can not yet be approached for large vessels. On the trial trip the Minneapolis Minneapo-lis developed 20,812 horsepower, and the total weight of all the machinery, with the water in the boilers, was 1,96 tous, so that the weight of machinery for each horsepower was about 210 pounds. Had the Minneapolis machinery been of the same relative weight as that of the Powhatan it would have weighed over 8,400 tons, or 1,000 tons more than the Minneapolis herself weighed on her trial trip. Chautauquan. |