The Welsbach osmium incandescent electric lamp was shown for the first time in public at a recent meeting of the Electrotechnical Union in Vienna. Osmium is a metal of the platinum group, and is found almost invariably in combination with iridium. It has the high specific gravity of 22.5 and is the heaviest known body. It is very hard and melts at the temperature of 2,500 degrees Centigrade. It can be brought to a high state of incandescence, emitting a brilliant light before this temperature is reached. Until recently the only uses of the metal have been in the iridium alloy, which has been employed for the tips of gold pens, and for some of its salts, which are used in microscopy and as chemical reagents. In making the lamps the gray osmium powder is reduced to a pasty mass by a suitable mixing ingredient and squirted into filaments. These are about the size of sewing thread. They are wound into their proper form and heated to redness in an atmosphere of ordinary illuminating gas. The heating is accomplished by electricity. The filament contracts considerably and rapidly while hot, and is reduced to metallic osmium in a few minutes. It has not been stated whether the bulbs in which these filaments are placed are exhausted of air or not. The consumption of the lamps is stated to be one and one-half watts per candle-power. It is also claimed that this efficiency is retained throughout the life of the lamp. In some curves which were shown, a lamp beginning at 14.8 candle-power at the end of 200 hours of burning showed 16.5 candle-power and slowly diminished until, after 1,000 hours of burning, it showed 15 candle-power. The light from the lamp is very white. It is stated that the commercial manufacture of the lamp is already well started. They are made for low voltages, twenty-five volts seeming to be standard. - L' Electricien.