Newcomen invented the atmospheric steam engine, in which the piston was lifted by steam, and when this was condensed the piston was forced to the bottom of the cylinder by the pressure of the atmosphere. Afterwards Watt improved upon the engine, and overcame the difficulty of removing the vast accumulations of water in the deep mines, about the middle of the eighteenth century. There is a curious relation between coal mines and the steam engine. The latter was invented among the former, and without its application to pumping purposes the invention would have been to a great extent worthless, for by means of the very substance raised from the mines the engine is kept in motion. The mines thus furnished the material with which the engine is operated, and only with the aid of the engine can the coal mines be properly worked. In the petroleum regions of America the borings and pumpings are frequently conducted by means of the gas which rises from the earth. Very often a steam engine is run without any other fuel than a stream of natural gas, conveyed beneath the boiler, and fed through a proper distributing apparatus. To the coal mine we are also indebted for that great boon of modern civilization, the railway. Coal is a heavy, bulky article, selling at a low price. Not only must it be removed from the earth, but it must be carried at a cheap rate, and often for long distances. Where there is no water communication the roads are the only mode of conveyance. Originally common earth roads were used, and the coal was carried in ordinary carts. These, roads were improved, and, after a time, were in the condition of stone causeways, or macadamized tracks. Afterwards wooden tracks were used, over which the wheels would roll more easily than upon ordinary roads. These wooden tracks were at first placed in the underground ways of the mines, and afterwards extended to the ways above ground. [Sidenote: INVENTION OF THE RAILWAY.] But wood is not durable; it soon rots and wears away. The wooden tracks were subsequently replaced by others of cast iron; originally these were grooved, but subsequently they were furnished with a lateral flange. Afterwards wrought iron was substituted for cast iron. In the first instance strips of cast iron were placed upon wooden rails, forming the old-fashioned strap rail. Afterwards was invented the ordinary rail as we now find it. The flange was removed from the rail, and placed upon the wheel, and thus, step by step, the modern railway came into existence.