Abstract
LONDON. Royal Society, February 18.—Sir William Crookes, president, in the chair.—Prof. W. A. Bone and others: Gaseous combustion at high pressures. Mixtures of methane with less than its own volume of oxygen were exploded in steel bombs at initial pressures of between 8 and 32 atmospheres. The results were in harmony with the “hydroxylation” theory of hydrocarbon combustion put forward some years ago by Prof. Bone. Results of experiments upon an equimolecular mixture of ethane and oxygen have again confirmed the hydroxylation theory. Another section of the paper deals with an experimental determination of the relative affinities of methane, hydrogen and carbon monoxide for oxygen in flames. It is shown (i) that the affinity of methane is at least twenty times as great as that of hydrogen; (2) that when mixtures corresponding to CH4 +O2+ xH2 are fired under high initial pressures, in which the partial pressures of methane and oxygen are kept constant and x only varied, the distribution of oxygen between the methane and hydrogen varies with x2—which means that hydrogen is burnt directly to steam in flames as the result of the tn-molecular change 2H2 + O=2H2O, and not (as some have supposed) indirectly through hydrogen peroxide. The affinity of carbon monoxide is shown to be comparable with that of hydrogen for oxygen in flames. The final section describes experiments in which the whole pressure curves, up to and far beyond the attainment of maximum pressure, were recorded when mixtures corresponding to (1) 2H2 + O2 + 4N2, (2) 2CO + O2 + 4N2, and (3) CH4 + O2 +4N2 are exploded under initial pressure of about 50 atmospheres. The rates of attainment of maximum pressure in each case have no direct relation to the order of affinities of the various gases for oxygen.—Prof. W. M. Hicks: The orbits of a charged particle round an electric and magnetic nucleus. Two problems are discussed—the orbits of α-particles and the orbits of electrons round nuclei containing mass, a definite number, n, of positive electronic charges and a definite number, N, of co-axial magnetons—the motion being in their equatorial planes. It is found that combined systems (atoms) with α-particles may exist in which the α-particle revolves in permanent connection with the nucleus, provided the internal energy of the atom is greater than a certain critical value, and that states of “radio-active” instability occur in which, after a combination of long duration, the α-particle is shot off to infinity. The exact velocity of emission in any case depends on the values of the n, N, but it is of the order of magnitude of the velocity of emission of α-rays from radium. In the case of electronic orbits, in addition to the combined systems with internal energy less than from infinity, there can exist also permanent systems in which the internal energy is greater than that from infinity, although less than a certain critical amount, and in which again states of “radio-active” instability occur of the proper order of magnitude.—S. Chapman: The lunar diurnal magnetic variation and its change with lunar distance. Balfour, Stewart, and Schuster have developed a theory of the solar diurnal magnetic variations which attributes them to electric currents in the upper atmosphere, impelled by electroiiiotive forces produced by the motion of the air across the earth's permanent magnetic field. The atmospheric conductivity is supposed to be wholly or partly due to solar influence and varies with the sun's hour angle. This theory apparently applies also to the lunar diurnal magnetic variations which possess a semi-diurnal component of constant phase, together with other components the epochs of which depend on the angular distance between the moon and sun; hence, when averaged over a lunation, all components save the former disappear. The suggested solar influence on the atmospheric conductivity is thus supported, and a semi-diurnal atmospheric oscillation—such as a lunar atmospheric tide—is suggested as the source of the magnetic variations. Before this theory was developed, Brown (Trevandrurn Observations, 1863) had found that the amplitude of the 12-hour magnetic component at perigee was to that at apogee in the ratio of (lunar distance)–3 at the two epochs—“as in the tidal theory,” he briefly remarked; but Figee (Batavian Observations, 1903) disputed this conclusion. The present paper discusses the evidence, of this direct kind, for or against a tidal origin of these magnetic variations. Brown's and Figee's data are used, together with much newly computed material from other observatories. The total hypothesis is confirmed, although on account of the accidental errors affecting the minute quantities under discussion, the exact law of (distance)–n, with n=3, is not beyond question, but if n is assumed necessarily integral, its value is certainly 3 and not 2 or 4.—Lt.-Col. J. W. Gifford: Some temperature refraction coefficients of optical glass. This is a supplement to a paper read in 1912 in which the refractive indices for 13 wave-lengths of 27 different glass meltings were given by the author. To this table are now added similar indices for six more Jena glass meltings, including those for the recent fluor crown. This is followed by a table of the temperature refraction coefficients for all the glass meltings dealt with, and attention is directed to the abnormal coefficients for fluor crown which is a minus quantity. An attempt is then made to determine, if only approximately, the influence of barometric changes on the refractive powers of optical glass which would seem to be, similarly, a minus quantity, amounting to something like six units in the sixth decimal place only.
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Societies and Academies . Nature 94, 717–719 (1915). https://doi.org/10.1038/094717a0
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DOI: https://doi.org/10.1038/094717a0