Reduced consumption of coal in steamers.
In steam vessels a remarkable economy of fuel has of late been attained. In his lecture at Bradford, Mr. Siemens said, ‘A striking illustration of what can be accomplished in a short space of time was brought to light by the Institute of Mechanical Engineers, over which I have at present the honour to preside. In holding their annual general meeting in Liverpool in 1863, they instituted a careful inquiry into the consumption of coal by the best engines in the Atlantic steam service, and the result showed that it fell in no case below 4½ lbs. per indicated horse-power per hour. Last year they again assembled with the same object in view in Liverpool, and Mr. Bramwell produced a table showing that the average consumption by 17 good examples of compound expansive engines did not exceed 2¼ lbs. per indicated horse-power per hour. Mr. E. A. Cowper has proved a consumption as low as 1½ lbs. per indicated horse-power per hour in a compound marine engine, constructed by him with an intermediate superheating vessel. Nor are we likely to stop long at this point of comparative perfection, for in the early portion of my address I have endeavoured to prove that theoretical perfection would only be attained if an indicated horse-power were produced with 1/5.5 lb. of pure carbon, or say ¼ lb. of ordinary steam coal per hour.’