No startling changes of practice in the metallurgy of tungsten are known to have taken place, but there has been a steady betterment of the art, improvement in the quality of ferrotungsten, a shifting in localities of reduction, and a considerable change in the manner of use. The wasteful, lazy demand for ores of high concentration and of great purity common before the war has given way before more enlightened and intelligent practice, until firms both in this country and in England make a specialty of using low-grade or impure ores, though seemingly much more advance has been made here than abroad. One firm, the Chemical Products Co. (Washington, D. C.) was organized specifically to buy ores carrying less than the 60 per cent. tungsten trioxide (WO₃) demanded by other American firms, and ores containing sulphur, copper, arsenic, bismuth, tin, antimony, phosphorus, or other impurities to which most users objected. Two firms, the Black Metal Reduction Co., and the Tungsten Products Co., both of Boulder, Colorado, were organized to handle materials such as tailings carrying as little as 1 per cent. tungsten trioxide, and they said that they were able to pay for gold and silver in the ore. Several firms make tungsten trioxide or tungstic acid (H₂WO₄) for ferrotungsten makers. Firms have also made artificial scheelite (CaWO₄) for the same trade, using off-color ores in the process. Powdered ferrotungsten made by chemically precipitating an iron tungsten salt from solution and reducing it to a metallic powder carrying 4 to 11 per cent. iron has been produced by several firms and seems to have started a demand for powdered ferrotungsten, so that firms are now finely grinding the massive ferrotungsten. Claims for better furnace practice which greatly cuts down the consumption of current and makes a saving of 90 to 96 per cent. instead of the usual 80 per cent. are also made. Several firms are making ferrotungsten powder and tungsten powder in iron tubes or other iron containers instead of in the graphite crucibles used before the war.