Abstract
LONDON. Royal Society, November 21.—Sir Archibald Geikie, K.C.B., president, in the chair.—A. S. Russell and R. Rossi: An investigation of the spectrum of ionium. The arc spectrum of an active preparation of ionium oxide mixed with thorium, separated by Prof. B. B. Boltwood from the pitchblende residues loaned to Prof. Rutherford by the Royal Society, has been investigated with a large Rowland grating. The complete spectrum of thorium was obtained, but no new lines were observed that could be attributed to ionium. It was deduced that if ionium were half transformed in 100,000 years, the preparation should contain about 16 per cent. of ionium oxide. By adding cerium and uranium to the preparation, it was found that 1 per cent. of the former and 2 per cent. of the latter could be easily detected spectroscopically. It was consequently concluded that the period of ionium cannot exceed 12,000 years. This result, taken in conjunction with Soddy's results on the period of ionium, points to the existence of at least one new, comparatively long-lived body between uranium and ionium in the disintegration series.—J. A. Gray: A note on the absorption of β rays.—J. A. Gray: The similarity in nature of X and primary γ rays. (1) Absorption experiments show that there is no fundamental difference in the absorption of X and γ rays. (2) The primary γ rays of radium E excite the characteristic radiations (series K) of silver, tin, barium, cerium, praseodymium and neodymium. (3) The scattering of the primary γ rays ofradium E is probably similar in character and magnitude to that of ordinary X-rays.—J. Crosby Chapman: The spectra of fluorescent Röntgen radiations. Radiations belonging to groups K L have been investigated as regards their X-ray properties. The absorption of the various radiations of both groups in copper, silver, and platinum has been found. In all cases it is shown that, if radiations from different groups suffer the same absorption in aluminium, then they are equally absorbed in any other element.—Dr. Walter Wahl: Optical investigation of solidified gases. II., the crystallographic properties of hydrogen and oxygen.—R. E. Slade: An electric furnace for experiments in vacuo at temperatures up to 1500° C. This furnace was designed with a view to investigate, at temperatures up to 1500° C., certain cases of heterogeneous equilibrium, in which the equilibrium is defined by the pressure of the system. Instances are the dissociation of oxides, nitrides, and carbonates and the reduction of oxides by carbon.—R. E. Slade and F. D. Farrow An investigation of the dissociation pressures and melting points of the system copper—cuprous oxide. The melting point (temperature, composition) diagram of the system copper—cuprous oxide has been constructed. The following are the principal points:— Melting point of copper 1083°. Eutectic Cu2O 3.5 per cent., Cu 96.5 per cent.; 1065° (determined by Heyn). Two liquid phases appear at 1195°, the denser one having the composition Cu2O 20 per cent., Cu 80 per cent., and the lighter one Cu2O 95 per cent., Cu 5 per cent. Melting point of cuprous oxide 1210°. The critical temperature at which the two liquid systems become identical is too high to be determined.—Dr. A. Russell: Note on the electric capacity coefficients of spheres. In connection with 'Mr. Jeffery's paper published in vol. lxxxvii. of the Proceedings, p. 109, the author gives and refers to formulæ by means of which the values of the capacity coefficients of equal spheres can be easily found. He uses these formulæ to check the tables given in Mr. Jeffery's paper.—W. J. Harrison: The motion of viscous liquid due to uniform and periodic motion maintained over a segment of an infinite plane boundary.—Prof. B. Hopkinson and G. Trevor-Williams: The elastic hysteresis of steel. A bar of steel, the reduced portion of which is 4 in. long by in diameter, is subjected to alternating stress in the high-speed fatigue-testing machine described in a previous communication. This machine gives direct axial stress up to range of 3o tons per square inch or more, between equal limits of tension and compression, at a rate of about 120 cycles per second. The elastic hysteresis is measured by determining, with the aid of thermo-couples, the fall of temperature between the centre of the piece and each end when it is undergoing alternating stress within the elastic range. The dissipation of energy corresponding to a given fall of temperature is determined by heating the specimen with an electric current and measuring the watts dissipated by resistance. In the mild steel used in the experiments the energy dissipated per cycle when the limits of stress are ± 121/2 tons per square inch (giving a range of 25 tons, which is within the limiting elastic range as determined by ordinary fatigue experiments) is about 25,000 ergs per c.c., and gives a fall of temperature of about 5°. This is of the same order of magnitude as that due to the magnetic hysteresis in similar material under strong magnetic forces. The elastic hysteresis varies approximately as the fourth power of the stress range.—W. R. Bousfield: Ionic size in relation to molecular physics, together with a new law relating to the heats of formation of solid, liquid, and ionic molecules. In a former paper it was shown that ionic volumes (derived from mobilities) and solution volumes were connected by an empirical linear relation.
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Societies and Academies. . Nature 90, 400–403 (1912). https://doi.org/10.1038/090400a0
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DOI: https://doi.org/10.1038/090400a0