Coal is King?

Coal is King to-day, says F. F. Coleman in Everybody's Magazine. Whether we use steam engines, electric engines, gas engines, compressed-air engines, or others to drive the wheels of industry, the one great source of energy is coal.

Under the best conditions, we waste six-sevenths of the heat value of this fuel, and it may fairly be estimated that in general practice hardly the fifteenth part of its value is realized for actual work.

Here, then, is a field for the genius of the inventor wide enough to satisfy the most ambitious. First, the task is to draw from coal something like its real value in work, and next to find a substitute to provide against the time when the storehouses of coal, petroleum, natural gas, and other fuels shall be emptied. Thomas A. Edison, whose achievements in applied science. have left him without a peer, and Nikola Tesla, the great necromancer in the field of electricity, have set for themselves the task of solving this problem, and mighty men of science in Europe are working toward the same end. Mr. Edison's aim is to find a way toward greater economy in the use of fuel. A bucketful of coal, he has declared, should drive an express train from New York to Philadelphia, and a few tons be sufficient for the ocean steamship, where now her bunkers. must hold thousands.

That there is hope for those who seek higher economies in the direct use of fuel is evidenced by advances already made. The boiler and steam engine of a century ago, at its best, was capable of giving back but 6 per cent. of the energy of the coal, while to-day they return 14 per cent., and coal turned into fuel-gases promises to give still higher results, when used through the medium of gas engines, than can be had by turning its heat into steam.

Something of what we should be able to accomplish is indicated by figures.

In every pound of coal resides an energy which scientists express in heat units, each of which is capable of lifting 772 pounds one foot high. An average quality of coal contains 14,000 heat units, representing in round numbers 10,000,000 foot-pounds of energy. What work a pound of coal should do may be judged by comparing these figures with those which represent the labor of man and of a horse.

A hod-carrier, making his weary trips with brick and mortar, climbing stairs or a ladder, will in a day of ten hours exert 2.088.000 foot-pounds. One pound of coal burned under perfect conditions. would do five times as much work.

A horse drawing a cart or plough expends 12,441,600 foot-pounds in the course of a day's work. The burning of one and one-quarter pounds of coal should do as much.