Although the exhaustion of coal is a distant prospect, there are clear signs of the approaching exhaustion of certain grades of coal. It has been estimated that the output of American anthracite will seriously decline in 60 to 100 years. Probably this will result in a change in practice, the use of coke, and other methods of house heating. If the rate of production continues to increase, high-grade American steam coal, New River and similar grades, will probably be exhausted in a little over 150 years. American coking coal of the best Connellsville quality is of equally short duration. British coal of similar high grade may last longer than American, as the production rate is less rapid, even though the total American coal should last much longer than the British. POLITICAL CONTROL In several countries state ownership of coal mines is established; as, for example, in parts of Prussia, Australia, Chile and Bulgaria. In others the undeveloped coal lands are still largely owned by the government, as in Alaska and the western United States. In some countries the government retains control of all mineral rights, simply leasing the property and granting a mining concession. Many governments have a department or administration of mines. In every country, of course, in an emergency, the sovereign state would exercise control of coal resources as fully as was necessary. Where the state owns mines, and favors organization, as in Germany, the more drastic regulation of war time is easily effected. It is quite possible that coal may in time be generally considered a public utility. In England a movement toward nationalization of mines, with miners as well as the government having a hand in the control, seems to be making progress. England’s colonies excel all others in extent of coal resources. There is coal in Australia, Canada, India, New Zealand, South Africa, Rhodesia, Newfoundland, South Nigeria and British North Borneo--the total being many times greater than that in the British Isles. The colonies and possessions of France, Denmark, Portugal, United States and Japan have relatively small amounts of coal. Coal resources, along with other raw materials, have been influenced by some trade treaties. However, no permanent advantage in commerce has been secured to any nation by a trade treaty. Nearly all such treaties are made for short periods and renewed. If not satisfactory to one party they are soon corrected. Various informal or tacit agreements might be mentioned. When shipping was scarce during the war, England and the United States divided the coal business of South America according to the requirements of ship economy. Germany made agreements to send coal to Austria-Hungary and Switzerland during the period of the war. England had agreements with France, Spain, Portugal and Italy, these agreements changing with conditions, about supplies of English coal. COMMERCIAL CONTROL