ANSWERS TO A QUALITATIVE ANALYSIS PUZZLE* CARL OTTO. UNIVERSITY OR M m . ORONO, MAME Solution
A. B. C. D.
E. F. G. H. I.
J.
Lead nitrate. Magnesium chromate. Silver fluoride. Ferric oxalate. Barium thiocyanate. Zinc iodide. Arsenic acid. Hydrogen sulfide. Sodium carbonate. Sulfuric acid.
Carbon Arc Light Rivals Sunshine. At this time of year people do not need substitutes for sunshine but scientists a t the U. S. Bureau of Standards are nevertheless hard a t work analyzing the composition of the carbon arc, comparing it with the light of the sun. Studies have been made with arc lights using ordinary carbons, as well as those impregnated with various chemicals, known as white flame, red flame, and blue flame, and carbons containing cores of different metals. The effect of varying the current was also studied, using currents of 15, 30. 60. 90, and 122 amperes. The various kinds of radiation given off were studied by the use of quartz prisms and lenses for the ultraviolet rays vibrating too rapidly to be visible. The infra-red, or heat rays, were studied by a thermopile which gives an electric current when heated. The high-intensity arc, using a current of 120 amperes, has been found to be closest to the sun in spectral composition. I t emits considerable radiation of longer wavelengths which are not in the solar beam, it was stated, but this can be eliminated easily by using a window of fused quartz, which absorbs the long infra-red rays.-Science Sem'ce Shaking Steel Improves Quality. "Shake well before usingu-that injunction of drug-store fame, may eventually lead to the production of better Pords, if the practices of German steel mills be widely copied. Molten steel, it has long been known, contains dissolved gases, wbich, when the steel is cast, may cause blowholes that ruin a certain percentage of the praduct. Steel operators have long known that if they transport molten steel for any distance, the jarring causes the liberation of same of these gases. I t remained, however. for a German metallurgist, as reported in Iron Age, to devise a scheme by wbich a cupola furnace might be mechanically agitated during the blasting process, with a resulting removal of gases and sulfur from the melt. By means of a cam, the furnace is bounced a t the rate of ahout 100 jolts per minute. This liberates the gases in much the same way as shaking a bottle of ginger ale liberates carbonic acid. The steel is then of a high degree of purity and may be used in casting very thin objects, such as the 511s of motorcycle engines.-Science Senice
