Power in a Pound of Coal

A pound of coal can produce power sufficient to pull a large express train a distance of one sixth of a mile, going at the rate of fifty miles an hour, writes an expert locomotive engineer, who is quoted in The Coal Trade Bulletin. He continues as follows:—

"You would be surprised at the wonderful amount of work which the energy from this small quantity of coal can do. For the purpose of explaining, take, for instance, a pound of what might be called average coal, containing about ten thousand heat units. This would be somewhat smaller in size than a man's fist. If this pound of coal could be burned completely and entirely under water, and all its heat should go into the water, at a temperature of sixty-two degrees, five pounds of water could be raised to the height of one foot. If this pound of coal could be completely burned in water one foot deep, with a temperature of sixty-four degrees, and all the heat from this coal be imparted to the water, this water would become sixteen degrees hotter, thus being suitable for a comfortable bath. If adapted to mechanical work, the ten thousand heat units in the one pound of coal would be equivalent to 236 horse-power. The 236 horse-power of potential energy contained in the pound of coal is enough to haul a train of eight cars for a period of one fifth of a minute, or a distance of one sixth of a mile, going at the rate of fifty miles an hour. It has also been found to be able to draw a cable train, including the grip-car and trailer, for a distance of two miles at the rate of nine miles an hour. It would also be of sufficient power to pull an electric car, well filled with passengers, for two miles and a half, at a rate of ten miles an hour. If the power in this pound of coal is compared with the work of a strong man used to hard labor, it would be found that there is more than sufficient power in the pound of coal to do in one minute the day's work, of eight hours, of five strong men. This is accounted for in this way: The work of a strong man, used to hard work, is estimated as being equal to one tenth of a horse-power. The eight hours he works is equivalent to four hundred and eighty minutes. Naturally, while working, a man makes a number of stops, either to rest or change the monotony of his position. These stops, then, would, without difficulty, take up one tenth of the man's time. Thus, this would reduce the time of actual work down to four hundred and thirty-two minutes. This time, at one tenth of the horse-power, makes the of his day's labor amount to 4.32 horse-power. At this rate it is shown that it would take twenty-six hundred strong men, working constantly, to do jointly the same amount of work in one minute as can be done by the single pound of coal. Another line of work in which the superiority of a pound of coal is shown beside the labor of man is that of sawing wood. A man may consider himself a swift sawyer, by making sixty strokes a minute, each stroke of the blade having progressed five feet a minute; but a circular saw, driven by machinery, may be put through seventy times that distance and saw seventy times as much wood. Still, this little pound of coal has the power to keep in operation one hundred and eighty such saws."

Thanksgiving Proclamation
November 7, 1901

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