The greatest improvement that can be imagined in the iron situation will be in the discovery and use of alloys or mixtures of iron with other materials. Steel, the strongest of all forms of iron, is an alloy of iron and carbon, and for various purposes these are further mixed with nickel and silicas. Many other alloys have been discovered within the last few years, and each makes possible new uses for iron requiring greater strength. One of the best of these is a mixture of iron and silicon, called ferro-silicon. Silica is one of the cheapest and most abundant materials of all the earth's products, so its combination with iron will greatly lengthen the life of the iron supply; and it is probable that in the future combinations of other materials will yield better and cheaper metals than any thus far produced. The amount of metal which can be reworked is constantly increasing. Most of the iron factories remelt large quantities of old iron, to be used with the new, and this will lessen each year the demand on the ores. It is also possible that new deposits of iron ore will be found and these will greatly increase the supply. But from the whole iron situation we may draw the following conclusions: First, the amount of iron remaining in the ground is very uncertain. It may be more, or it may be less, than the present estimate. Second, if the estimates are nearly correct, and if the present rate of increase continues, all the high-grade ores will be exhausted by the time the small boys of to-day are the business men of the nation. Third, the best methods of reducing the drain on the supply are, (a) The use of old iron as a mixture; (b) Carrying a part of the freight by water to reduce the amount of iron required by the railroads; (c) The larger use of concrete and cement to take the place of steel in buildings; (d) Lessening the amount used for war; (e) The use of alloys. This opens a large and promising field for invention. (f) More care in preserving articles made of iron. This is a practical thing for every person in our country to do. Every farm implement, or tool, that stands out in the rain or is left without shelter during the winter, every article carelessly lost or broken, has its part in making conditions worse. All that are well cared for help to make the iron supply last a little longer. REFERENCES Iron and Steel at Home and Abroad. (Andrew Carnegie.) Conservation of Ores and Related Minerals. (Carnegie.) Report Governor's Conference. Report National Conservation Commission. Reports Geological Survey. Mineral Resources of the U. S. in 1908. Advance chapters available. CHAPTER VIII OTHER MINERALS GOLD Iron, in its usefulness to man, stands in a class to itself; but there are dozens of other minerals that have their part in the comfort and convenience of our daily life. Most of these, however, are found in comparatively small quantities and have few uses.