In their report made for the Smithsonian Institution, Gilbert and Pogue point out that "there are in one ton of good bituminous coal, fifteen hundred pounds of smokeless fuel analogous to anthracite, ten thousand cubic feet of gas, twenty-two pounds of ammonium sulphate, two and one-half gallons of benzol, and nine gallons of tar" and that lignite gives almost as much of these commodities. Apart from the fuel values represented by the "smokeless fuel analogous to anthracite" the gas and benzol, the ammonium sulphate, and tar have unique values as fertilizers, and the source of those mineral elements from which our dyes and a large part of our modern medicines are made. The process used to extract these commodity values is similar to that which nature used in making anthracite, except that the volatile matter which the geological revolution drove off into the air is collected and utilized. The gas created by the process can be delivered by pipe lines over practically any distance to the centers of consumption, or, with the help of the internal-combustion engine, converted into electrical energy at the mine. Gas as a fuel has the great advantage that it eliminates both storage and haulage, and produces the same amount of heat from about one-half the amount of coal, and since it can be produced as needed all the year round it will go far to eliminate the seasonal character of coal mining. Moreover, wherever heat rather than light or power is desired, gas, in the present state of technical development, is even more economical than electricity. Under the by-product system the present annual coal output can be made to more than double its service in driving machinery and in addition it can be made to contribute heavily to our supply of fertilizers, motor fuel, and chemical products. It is estimated that the aggregate loss resulting from the present wasteful utilization of coal is over ten dollars a year for each inhabitant of the United States.