Читать книгу Locomotive Engine Running and Management - Angus Sinclair - Страница 78

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It is not necessary that a man should be deeply read in natural philosophy, to understand intimately what are actually the scientific laws of the business of firing. Mr. Lothian Bell, the eminent metallurgist, somewhere expresses high admiration for the exact scientific methods attained in their work by illiterate puddlers. Although they knew nothing about chemical combinations or processes, they manipulated the molten mass so that, with the least possible labor, the iron was separated from its impurities. In a similar way, firemen skillful in their calling have, by a process of induction, learned the fundamental principles of heat-development. By experiments, carefully made, they perceive how the greatest head of steam can be kept up with the smallest cargo of coal; and they push their perceptions into daily practice.

If an accomplished scientist were to ride on the engine, observing the operations of a first-class fireman, he would find that nearly all the carbon of the coal combined with its natural quantity of oxygen to produce carbon dioxide, thereby giving forth its greatest heat-power; and that the hydro-carbons, the volatile gases of the coal, performed their share of calorific duty by burning with an intensely hot flame. He would find that these hydro-carbon gases, although productive of high-power duty when properly consumed, were ticklish to manage just right, for they would pass through the flues without producing flame if they were not fully supplied with air; and, if the supply of air were too liberal, it would reduce the temperature of the fire-box below the igniting-point for these gases, which is higher than red-hot iron, and they would then escape in the form of worthless smoke. Our model fireman manages to consume these gases as thoroughly as they can be consumed in a locomotive fire-box.