758 



NATURE 



[December 2, 1922 



of strength is reached in acids containing four atoms 

 of oxygen round the central atom of the ion. — C. J. 

 Smith : On the viscosity and molecular dimensions 

 of hydrogen selenide. Attention has recently been 

 directed to the relations which exist between the 

 molecular dimensions of those gaseous hydrides which 

 have the same molecular number. In the series 

 krypton, hydrogen bromide, hydrogen selenide, and 

 arsine there were no data for hydrogen selenidi 



I wo factors are necessary for the proper estimation 

 • if dimensions of a gaseous molecule, namely, the 

 coefficient of viscosity, and its rate of variation with 

 temperature. The viscosity of hydrogen selenide at 

 atmospheric temperature lias been measured, but 

 the almost complete decomposition of the gas at 

 steam temperature has prevented any trustworthy 

 experimental determination of the temperature varia- 

 tion being made. The numerical results obtained 

 confirm the supposition that the gaseous molecules 

 HBr, H 2 Sc, and AsH 3 have a central atom which 

 resembles an atom of krypton, and that the increase 

 in A in passing along the series is to be attributed to 

 the hydrogen nuclei which have become attached to 

 .the central atom. As the hydrogen atoms in the 

 molecule multiply, the distance of each hydrogen 

 mi. leus from the centre of the molecule increases 

 more and more rapidly. — W. R. G. Atkins: The 

 hydrogen concentration of natural waters and some 

 etching reagents in relation to action of metals. 

 The results obtained are summarised as follows : 

 Natural waters are usually between pH6 and />H8-3, 

 unless when rendered more acid by oxidation of 

 sulphur from pyrites or by metallic salts. Bog pools 

 may be as acid as pH$. Photosynthesis increases 

 the pH value. Ferrous salts in solution become more 

 acid on standing, with precipitation of ferric hydroxide. 

 The latter is completely precipitated before ferrous 

 hydroxide, as the solution is made progressively 

 more alkaline. Even at pHj-i the precipitation i 

 ferrous hydroxide is incomplete. Hence a trace of 

 acid suffices to attack iron, and the hydroxide 

 produced through hydrolysis is oxidised and pre- 



ipitated. The hydrolysis equilibrium is thereby 

 upset and acid is regenerated. Buffer mixtures and 

 acids of relatively low hydrogen ion concentration 

 might be used as etching agents. 



Cambridge. 



Philosophical Society, October 30. — Prof. A. C. 

 Seward, president, in the chair. — H. Hartridge and 

 F. J. W. Roughton : Determinations of the velocity 

 with which carbon monoxide displaces oxygen from 

 its combination with the blood pigment haemoglobin. 

 The velocity of the reaction, which is considerable, 

 was measured by utilising the fact that light displaces 

 the system from equilibrium by reducing the amount 

 of the carbon monoxide haemoglobin in a solution 

 of haemoglobin containing oxygen and carbon mon- 

 oxide. The relationship between the amounts of the 

 oxy- and carbon monoxide haemoglobin at any 

 moment was determined by the reversion spectro- 

 scope, which makes use of 'the fact that the wave- 

 length of the a band of the mixed pigment varies 

 with the relative concentration of the pigments. 

 Two methods of measuring the velocity of reaction 

 were employed : — (a) The solution was caused to 

 (low turbulently from a glass tube exposed to light, 

 down a second glass tube in the dark. In this tube 

 the equilibrium returned to its " dark " position, and 

 from the rate of flow measurements by the spectro- 

 scope give the relative amounts of oxy- and carbon 

 monoxide haemoglobin at any moment, (b) The 

 solution remained in one vessel, the exposure to 

 light being suddenly cut off, and the time measured 



NO. 2770, VOL. I IO] 



with a chronometer for the relationship between the 

 oxy- and carbon monoxide haemoglobin to reach a 

 definite value as shown by the spectroscope. Velocity 

 constants were calculated, assuming the reaction to 

 be expressible by a simple chemical equation. The 

 temperature coefficients calculated from the results 

 obtained at other temperatures agree closely, the 

 mean value being 2-5. These results fit m with the 

 view that the combinations of oxygen and carbon 

 monoxide with haemoglobin are of a simple chemical 

 nature. — G. H. Hardy and J. E. Littlewood : Some 

 problems of Diophantine approximation. — J. Chadwick 

 and C. D. Ellis : A preliminary investigation of the 

 intensity distribution in the /3-ray spectra of radium 

 B and C. — C. G. Darwin and R. H. Fowler: Parti- 

 tion functions for temperature radiation and the 

 internal energy of a crystalline solid. — J. E. Littlewood 

 and E. A. Milne : On an integral equation. — E. V. 

 Appleton : The automatic synchronisation of triode 

 oscillators. — P. L. Kapitza : Note on the curved 

 tracks of ^-particles. — G. T. Walker : Meteorology 

 and the non-flapping flight of tropical birds. — Major 

 P. A. MacMahon : The algebra of symmetric functions. 



Royal Irish Academy, Novembei 13. — Prof. Sydney 

 Young, president, in the chair. — S. Young : A note 

 on azeotropic mixtures. It is now possible to predict, 

 either with certainty or with considerable confidence, 

 whether an alcohol of the methyl alcohol series not 

 yet investigated can or cannot form a binary mixture 

 of minimum boihng-point with hexane, benzene, or 

 toluene, or a ternary azeotropic mixture with one 

 of these hydrocarbons and water. 



Paris. 



Academy of Sciences, November 6.— M. Albin 

 Haller in the chair. — The president announced the 

 death of E. Bouty. — L. Lindet : Concerning the 

 coagulation of latex. Remarks on a communication 

 by M. Yernct on the effects of adding calcium chloride 

 solution to the latex of rubber plants. In 1914 the 

 author published an account of a similar action 

 of calcium chloride in the coagulation of milk casein. 

 — Jean Effront : The absorption of pepsin and 

 hydrochloric acid by foods. Starting with the 

 observation that certain filter papers proved to be 

 active absorbents of pepsin, experiments have been 

 carried out on the absorptive powers of various fruits 

 and vegetables for pepsin and also for hydrochloric 

 acid. The amounts absorbed were considerable, and 

 vary with the fruit and with the acidity of the 

 medium. The therapeutical aspects of these facts 

 are discussed. — Serge Bernstein : The asymptotic 

 development of the best approximation by poly- 

 nomials of rational functions of degrees indefinitely 

 increasing. — Birger Meidell : A problem of the 

 calculus of probabilities and of mathematical statistics. 

 A discussion of Tchebycheff's theorem on the proba- 

 bilities of errors greater than the average error with 

 special reference to the calculus of probabilities and 

 mathematical statistics. — P. J. Myrberg : The singu- 

 larities of automorphic functions. A correction to 

 the note of October 23 on the same subject. — J. 

 Le Roux : Gravitation in classical mechanics and in 

 Einstein's theory. — Louis de Broglie : Interference 

 and the quanta theory of light. — Paul Pascal : The 

 magnetic analysis of silicates and the silicic acids. 

 From measurements of magnetic susceptibility of 

 ill. 11 acid in varying degrees of hydration it is 

 concluded that all the forms of " hydrated silica " 

 studied behave magnetically as mixtures of anhydrous 



