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Flames of atomic hydrogen
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CURRENT TOPICS.
[J. F. I.
avoid the conclusion, then, that nuclear changes having an energy value perhaps fifty times as great as the energy changes involved in observed radio-active processes are taking place all through space, and that signals of these changes are being sent to us in these highfrequency rays." The author inclines to the belief that in the capture of electrons by positively charged nuclei is to be sought the process responsible for the penetrating rays. I f it be that all space is not traversed in all directions by these rays, the alternative hypothesis must be adopted that electrons traverse space in all directions with high speed and in the upper layers of the atmosphere generate the rays to be accounted for. This explanation " t o o , fills space with rays of one sort or another, travelling in all directions with the speed of light. F r o m some such conception as this there now seems to be no escape." W h e n the penetrating rays impinge on the earth, by the Compton effect they produce soft scattered radiation of the kind that was in evidence on Pike's Peak. On this mountain there was more of the soft radiation than in Pasadena because at the higher altitude there was more of the penetrating radiation to be transformed, it not yet having been subjected to the absorption of the air below the level of the mountain top. The limits of the spectrum of radiation have by this investigation been enormously extended, though the earlier observers are deserving of great credit. G.F.S. F l a m e s of A t o m i c H y d r o g e n . I. LANGMUIR. (Science, November 20, 1 9 2 5 . ) - A s early as I9I I Langmuir concluded that hydrogen is to a great extent turned into atomic hydrogen at temperatures of 2500 ° K. or higher. Further examination convinced him that by heating a platinum or tungsten filament above 13oo ° K. in hydrogen at low pressure, atomic hydrogen is formed. It was calculated that the heat of combination of two grams of atomic hydrogen is 90,000 small calories. Later he obtained the gas dissociated into the atomic form by sending 20 amperes of current from one tungsten rod 6 mm. in diameter to another in a stream of hydrogen. The resulting arc of a red color was not more than 2 cm. in length with voltages from 300 to 800. " Iron rods 2 or 3 mm. in diameter melted within a couple of seconds when they were held 3-5 cm. above the arc. By directing a jet of hydrogen from a small tube into the arc, the atomic hydrogen could be blown out of the arc and formed an intensely hot flame of atomic hydrogen burning to the molecular form and liberating 90,000 calories per gram molecule--about 5 ° per cent. more than in an oxy-hydrogen flame." Molybdenum and tungsten were melted when held close to the arc. Quartz was harder to melt than the first of these. By the process just described iron can be welded or melted with the avoidance of carbon, nitrogen and oxygen, and also alloys of chromium, aluminum, silicon or manganese. G.F.S.
CURRENT TOPICS.
[J. F. I.
avoid the conclusion, then, that nuclear changes having an energy value perhaps fifty times as great as the energy changes involved in observed radio-active processes are taking place all through space, and that signals of these changes are being sent to us in these highfrequency rays." The author inclines to the belief that in the capture of electrons by positively charged nuclei is to be sought the process responsible for the penetrating rays. I f it be that all space is not traversed in all directions by these rays, the alternative hypothesis must be adopted that electrons traverse space in all directions with high speed and in the upper layers of the atmosphere generate the rays to be accounted for. This explanation " t o o , fills space with rays of one sort or another, travelling in all directions with the speed of light. F r o m some such conception as this there now seems to be no escape." W h e n the penetrating rays impinge on the earth, by the Compton effect they produce soft scattered radiation of the kind that was in evidence on Pike's Peak. On this mountain there was more of the soft radiation than in Pasadena because at the higher altitude there was more of the penetrating radiation to be transformed, it not yet having been subjected to the absorption of the air below the level of the mountain top. The limits of the spectrum of radiation have by this investigation been enormously extended, though the earlier observers are deserving of great credit. G.F.S. F l a m e s of A t o m i c H y d r o g e n . I. LANGMUIR. (Science, November 20, 1 9 2 5 . ) - A s early as I9I I Langmuir concluded that hydrogen is to a great extent turned into atomic hydrogen at temperatures of 2500 ° K. or higher. Further examination convinced him that by heating a platinum or tungsten filament above 13oo ° K. in hydrogen at low pressure, atomic hydrogen is formed. It was calculated that the heat of combination of two grams of atomic hydrogen is 90,000 small calories. Later he obtained the gas dissociated into the atomic form by sending 20 amperes of current from one tungsten rod 6 mm. in diameter to another in a stream of hydrogen. The resulting arc of a red color was not more than 2 cm. in length with voltages from 300 to 800. " Iron rods 2 or 3 mm. in diameter melted within a couple of seconds when they were held 3-5 cm. above the arc. By directing a jet of hydrogen from a small tube into the arc, the atomic hydrogen could be blown out of the arc and formed an intensely hot flame of atomic hydrogen burning to the molecular form and liberating 90,000 calories per gram molecule--about 5 ° per cent. more than in an oxy-hydrogen flame." Molybdenum and tungsten were melted when held close to the arc. Quartz was harder to melt than the first of these. By the process just described iron can be welded or melted with the avoidance of carbon, nitrogen and oxygen, and also alloys of chromium, aluminum, silicon or manganese. G.F.S.