The imaginative appeal of hydroelectric power has led many people to hope that water-power electricity would come to the aid of coal and possibly replace it. But Mr. Charles P. Steinmetz, of the General Electric Company, tells us that the total available water power of the United States has been variously estimated at from fifty to one hundred million horse-power, that is, from one-sixth to one-third of the horse-power equivalent of our present annual coal production. He has gone further and calculated the maximum possible value of all water power beyond which the ultimate skill of invention could never possibly go. If every raindrop which falls anywhere in the United States, allowing only for the amount of water needed by agriculture and the loss due to seepage and evaporation, were collected and all the power which it could develop in its journey to the sea were efficiently utilized, the resultant energy would amount to just about the same as the total which we get out of our present coal consumption for all purposes. Water power--hydroelectric energy--can never replace coal. The waste of both petroleum and gas has been largely due to the unrestrained acquisitive instinct seeking quick wealth in response to the cry of the steam engine for more and more fuel. They were drafted into service because they could do the work of coal and do it more efficiently. But their diminishing supply makes it impossible for them longer to stave off the impending technical revolution in the coal industry. The miners are growing restive under the evils of intermittent employment, uncertain income, and demoralizing conditions of living. The public begins to rebel against irregularity of supply and ruinously high prices. The antiquated transportation system creaks and staggers under a load which the advance of technical science makes it unnecessary for it longer to carry. All these, taken together with the still-increasing demand for power to drive on production and pile up a surplus on which to base an advancing civilization, are forcing a new technical revolution upon the coal industry. CHAPTER IX THE TECHNICAL REVOLUTION The economic surplus which the industrial revolution of the latter eighteenth century created was the product of a crude, extensive exploitation of our natural resources. With the aid of the steam engine men skimmed the cream of the mines, the forests, and the new soil of the American continent.