day but devising fresh appliances to exhaust with ever greater rapidity the hoard of coal? There is just a certain number of tons of coal lying in the earth, and when these are gone there can be no more forthcoming. There is no manufacture of coal in progress at the present time. The useful mineral was the product of a very singular period in the earth's history, the like of which has not again occurred in any noteworthy degree in the geological ages that have since run their course. Our steam-engines are methods of spending this hoard; and what we often hear lauded as some triumph in human progress is merely the development of some fresh departure in a frightful extravagance. We would justly regard a man as guilty of expending his substance wastefully if he could not perform a journey without a coach-and-six and half-a-dozen out-riders, and yet we insist that the great steamers which take us across the Atlantic shall be run at a speed which requires engines, let us say, of 12,000 horse-power. If the number of passengers on such a vessel be set down as 500, we have for each passenger the united force of 24 horses, night and day, throughout the voyage. I expect our descendants will think that our coal-cellars have been emptied in a very wasteful manner, particularly when they reflect that if we had been content with a speed somewhat less than that at present demanded the necessary consumption of coal would have been reduced in a far greater proportion than the mere alteration of speed would imply.
Of course, no one will contend that the exhaustion of coal means the end of the human race; man lived here for tens of thousands of years before he learned how to use coal. There may be a sort of Chinese-like civilisa-
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