Table II.—Progress in the Economy of the Marine Engine, 1872 to 1901.1872.1881.1890.1901.Boiler pressure in pounds per square inch52.477.4158.5197Coal consumption in pounds per indicated horse-power per hour2.111.831.521.48Consumption on prolonged sea voyages in pounds per indicated horse-power per hour- - -21.751.55Piston speed in feet per minute376467529654
Table II.—Progress in the Economy of the Marine Engine, 1872 to 1901.
The advance of the century may be popularly expressed by stating that, whereas in the first coasting steamships built by the Scotts the fuel consumed in carrying 1 ton of cargo for 100 miles was 224 lb., the expenditure to-dayis from 4 lb. to 5 lb. The economy of the steam engine has accounted, as is shown in the Table, for a considerable part of this improvement. But, at the same time, the growth in the size of ships has enabled the normal speed of 10 knots to be realised, with an addition to engine power of much less ratio than the increase in the capacity of the steamer. As to speed, recent progress has been most marked in the Navy, and it is therefore fitting that here we should direct our attention to Naval work.