Abstract
LONDON. Royal Society, April 26.—W. A. Bone, D. M. Newitt, and D. T. A. Townend: Gaseous combustion at high pressures. Pt. III.—The energy-absorbing function and activation of nitrogen in the combustion of carbon monoxide. Nitrogen can no longer be regarded as an inert gas in the combustion of carbon monoxide, because when present as a diluent in a mixture of two volumes of carbon monoxide and one volume of oxygen undergoing combustion in a closed vessel under high pressure, it exerts an energy-absorbing influence which (a) retards attainment of maximum pressure, and (b) diminishes maximum temperature attained in explosion. The effects are much greater than those due to any other diatomic diluent. The energy so absorbed by nitrogen during the combustion period is slowly liberated as the system cools down after attainment of maximum temperature, and consequently the rate of cooling is greatly retarded. These effects are very marked in the case of a carbon monoxide-air mixture (2CO + O2 + 4N2). In consequence of such energy-absorption, nitrogen becomes chemically “activated” in such explosions, and while in this condition will combine with oxygen, forming oxides of nitrogen. If no nitrogen be present in a carbon monoxide-oxygen (2:1) mixture, carbon monoxide burns in oxygen at high pressures almost as rapidly as does hydrogen. There is no correspondingly large (if any) energy-absorbing effect (other than purely “diluent”) when nitrogen is present in hydrogen and oxygen mixtures similarly undergoing combustion, and there is no evidence of nitrogen being then activated. Two or three per cent. of hydrogen in a carbon monoxide-air mixture undergoing combustion prevents any material activation of the nitrogen. It appears that the influence of nitrogen in the carbon monoxide-oxygen explosions is due to its ability to absorb the particular quality of radiation emitted; such radiation is known to be of a different wavelength from that emitted during the flame-combustion of hydrogen. In other words, there seems to be some constitutional correspondence between carbon monoxide and nitrogen molecules, whereby the vibrational energy (radiation) emitted when one reacts with oxygen is of a quality readily absorbed by the other, the two acting in resonance.—R. A. Watson Watt and E. V. Appleton: On the nature of atmospherics. Observations with a cathode ray oscillograph, on the temporal variations of the electric force occurring in radio telegraphic atmospherics are described. The principal constants of six hundred typical atmospherics are examined. A bare majority are quasi-periodic, consisting normally of one complete oscillation, of duration 2000 micro seconds, the mean change of field being 0.128 volts per metre, with no marked unbalanced transport of electricity on the whole group. The second group consists of aperiodic impulses, of duration generally about 1250 micro seconds, but frequently reaching 0.025 ° of a second, the mean change of field being 0.125 volts per metre, with a seven to one numerical predominance of discharges tending to carry negative electricity to earth in the receiving antenna.—I. Masson and L. G. F. Dolley: The pressures of gaseous mixtures. Measurements have been made at 25° of the compressibilities up to 125 atm. of ethylene, argon, oxygen, and a series of binary mixtures of these. The volume of a compressed mixture usually exceeds the sum of the separate volumes of its two components, the excess depending on the molecular ratio of the two gases chosen and upon the pressure. Thus with an equimolecular mixture of argon and ethylene at 80 atm. the volume is greater than the additive value by 24 per cent. At a given pressure there is an “optimum” composition, and with a given composition there is an optimum pressure. Oxygen-ethylene mixtures behave quantitatively in the same way as argon-ethylene; oxygen and argon when mixed show a negligible volume increase, and are individually equally compressible. The pressure of a mixture at high densities exceeds the sum of those measured for the separate constituents; at moderate densities it is definitely less. The former occuirence is due to the actual space filled by the molecules; the latter is due to a mutual cohesion between each.—T. R. Merton and R. C. Johnson: On spectra associated with carbon. The spectral changes due to the admixture of helium to vacuum tubes containing carbon compounds, and the conditions for isolating the band spectra associated with carbon, have been investigated. The “high pressure CO” bands can be isolated almost completely; the “comet-tail” bands are found in vacuum tubes containing helium and carbon monoxide. In the presence of helium the distribution of intensity in the comet-tail -bands differs markedly from that observed by Fowler in tubes containing carbon monoxide at very low pressures. By the admixture of hydrogen the comet-tail bands are replaced by a system of triplet bands, and the wave-lengths of the heads of these bands fall into two distinct band series. In helium containing a small quantity of carbon monoxide a new line-spectrum has been observed under suitable conditions of excitation, which is attributed to carbon.—W. R. Bousfield and C. Elspeth Bousfield: Vapour pressure and density of sodium chloride solutions. A standard set of vapour pressure determinations at 18° C. for aqueous solutions of common salt at all concentrations was required. Water and the solution were introduced into the legs of a V tube surmounting a barometric column of mercury, excluding all air. This necessitated the boiling of the solutions so that they became of unknown concentration. The vapour pressure observations were therefore correlated to the densities of the solutions and the latter with a complete set of density observations at 18° C. made on solutions of known concentration accurate to ±2 in the fifth place of decimals.—F. A. Lindemann and G. M. B. Dobson: A note on the temperature of the air at great heights. The relatively high temperature of the atmosphere above 60 km. appears to be due to absorption of an appreciable amount of direct solar radiation. Thus there should be a large variation in temperature at these great heignts. Some evidence of such variation has been found.—G. H. Hardy and J. E. Littlewood: On Lindelöf's hypothesis concerning the Riemann zeta-function.
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Societies and Academies. Nature 111, 622–624 (1923). https://doi.org/10.1038/111622a0
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DOI: https://doi.org/10.1038/111622a0