It is probable that the comparatively recent discovery of mineral coal is due in a great measure to its close resemblance to stone. A savage or civilized man knows that an ordinary stone, whether white, red, blue, green, or gray, will not burn; then why should he suppose that a black stone will burn? Until a comparatively recent date there has been no great demand for coal as fuel. Many parts of the world at the present day are covered with immense forests, and for a hundred and perhaps thousands of years there will be no occasion in these localities to make use of the mineral fuel. [Sidenote: COAL AMONG THE ANCIENTS.] It is supposed that the Greeks and Romans had some knowledge of fossil fuel, but they made very little use of it, partly for the reason that they did not know the proper way to burn it, and partly because the forests in those days furnished all the fuel needed for industrial purposes. There were no manufactories and smelting establishments, and the working of metals was carried on in a very primitive way. Wood and charcoal were the only fuel, and most of the countries inhabited at that early day were favored with a warm climate, that for the most part of the year was comfortable enough by day, while blankets and other bed-clothing gave sufficient warmth by night. The laws of heat were not known; the pressure of vapor was not even thought of, or suspected; and mechanical force was derived from wind, from water, and from animated beings. When the winds did not blow the galleys were rowed by convicts, and in the absence of a stream of water, animals, and sometimes men, turned the mill. Occasionally in building aqueducts, large beds of coal were laid bare, but no attention was paid to them. In making one aqueduct, a branch of a canal was cut through a bed of rock, and at the bottom of that bed a valuable seam of coal was found, but nobody appears to have troubled his head about it. It is supposed by most writers that the discovery of coal occurred in the East. The Chinese have been credited with the discovery and invention of nearly everything in the world except the discovery of America and the invention of the electric telegraph. It is pretty certain that they were acquainted with mineral fuel from a very remote antiquity. They knew how to work it, and apply it to industrial uses, such as baking porcelain, drying tea, and the like. The Chinese, for hundreds of years, used to bake porcelain with mineral coal. It is only recently that mineral coal has been substituted for charcoal for this very same purpose in France, and it has been found to be quite economical. [Sidenote: CHINESE FIRE WELLS.]