December 8, 1923] 



NATURE 



851 



activity of the charcoal considerably, and it is sug- 

 gested that the iron acts as a spacing agent. The 

 proportion of hydrogen peroxide decomposed is 

 determined by both the activity of the charcoal and 

 the concentration of the solution. — E. E. Walker : 

 The influence of the velocity of compression on the 

 apparent compressibility of powders. The influence 

 of the duration of the load on the volume ratio of 

 compressed powder has been investigated, and the 

 isobaric curve has been correlated with the value 

 of the ratio resistance to impact to resistance to 

 static load. The exceptional readiness with which 

 powdered ammonium nitrate shrinks depends chiefly 

 on the high value of its velocity coefficient. — L. 

 Anderson : (i) An investigation of Smoluchowski's 

 equation as applied to the coagulation of gold 

 hydrosol. Colorimetric determinations of the rate 

 of coagulation of gold sols by hydrochloric acid, 

 potassium chloride, barium chloride, and aluminium 

 chloride have been carried out, and a region of rapid 

 coagulation is found in which Smoluchowski's equa- 

 tion holds fairly well. A slower region of coagulation 

 is found in which the equation is inapplicable. On 

 the whole, the equation in its present form is strictly 

 limited to rapid coagulation. (2) The effect of 

 sucrose on the rate of coagulation of a colloid by an 

 electrolyte. The coagulation of gold sols by hydro- 

 chloric acid, barium chloride, and potassium chloride 

 in the presence of varying amounts of sucrose has 

 been investigated. It is concluded that sucrose 

 exerts a definite peptising effect upon colloidal gold, and 

 also that it exerts a specific augmentation of coagula- 

 tion in the case of hydrogen and barium ions over 

 and above that of increasing the activity of these 

 two ions. It exhibits apparent antagonistic action 

 towards ions and gold sols. The experiments 

 indicate in general that the coagulating power of an 

 ion is dependent upon its activity rather than upon 

 its concentration, a conclusion which brings the 

 typical colloid phenomenon of coagulation into line 

 with the kinetics of chemical change in homogeneous 

 (molecular) systems. — H. H. Paine and G. T. R. 

 Evans : A method of measuring the rate of coagula- 

 tion of colloidal solutions over wide ranges. The 

 rate of coagulation of colloidal copper solutions has 

 been studied for a wide range of electrolyte con- 

 centrations by making use of the retarding effect 

 of starch. Very rapid coagulations can thus be 

 brought into the region of observation by ordinary 

 methods. A " transformation factor " can be obtained 

 which enables one to calculate what the rate of 

 coagulation would have been for the pure colloid. 

 The results agree closely with the equation deduced 

 by Freundlich for the variation of the rate of coagula- 

 tion with the concentration of the electrolyte, and 

 confirm the existence of a maximum rate of coagula- 

 tion. — J. A. V. Butler : Studies in heterogeneous 

 equilibria. Pt. I. The conditions at the boundary 

 surfaces of crystals and liquids are discussed with 

 the view of applying statistical methods to elucidate 

 the kinetics of surface processes and to co-ordinate a 

 number of different cases of heterogeneous equilibrium. 

 A molecule near the surface is under the influence of 

 two opposing attractive forces, that of the surface 

 and that exerted by the liquid. In general, these 

 result in a balance point at which the direction of 

 the resultant force reverses. Suitable approximate 

 statistical equations are deduced on this basis and 

 applied to the simplest cases of solubility. The 

 integration constants of the isochore for solubility 

 calculated by means of the equations obtained for 

 potassium, sodium, hydrogen, and silver chlorides, 

 are of the same order of magnitude as the experi- 

 "lontal valudS. 



NO. 2823, VOL. 112] 



Royal Statistical Society, November 20. — Sir J. 

 Athelstane Baines : The International Statistical In- 

 stitute and its fifteenth session. The International 

 Statistical Institute originated at the jubilee meeting 

 of the Royal Statistical Society. During the War, 

 its work was in abeyance, with the exception of that 

 carried on by the Permanent Office, which had been 

 established only a short time before hostilities began. 

 The Institute was able to convene its fifteenth session 

 to take place at Brussels last October. At the re- 

 quest of the League of Nations, through the Economic 

 Section, proposals for the organisation of statistics for 

 international comparisons were submitted to the Insti- 

 tute, and forwarded, as adopted, to the League. The 

 subjects dealt with were statistics of trade, of agricul- 

 tural production, and of fisheries, together with sugges- 

 tions as to the use and form of index-numbers bearing 

 on the economic situation. It is possible that the 

 counsel of the Institute may be sought by the League 

 systematically as time goes on, since the need of a 

 qualified adviser, independent and impartial, upon 

 international questions involving a statistical basis, 

 is becoming annually more apparent. 



Paris. 



Academy of Sciences, November 12. — M. Albin 

 Haller in the chair. — J. Costantin : The collection 

 and culture of Pleurotus Eryngii. Suggestions for 

 the cultivation of this edible mushroom (and other 

 species of Pleurotus) on waste land. — H. A. Lorentz 

 and Edouard Herzen : The relations between energy 

 and mass according to Ernest Solvay. — E. O. Lovett : 

 A functional property of certain surfaces. — Armand 

 Cahen : New continued fractions attached to cer- 

 tain operations. — Serge Bernstein : Quasi-analytical 

 functions. — Jean Chazy : The gravitation field of 

 two fixed masses in the theory of relativity. — Carl A. 

 Garabedian : A method of series. — Charles Nordmann : 

 The "turbulence" of the wind and the flight of 

 hovering birds. Discussion and criticism of the 

 views of Vasilesco Karpen on this subject. — Emile 

 Belot : Some consequences of the fact that all stars, 

 including the sun, must have passed through the 

 nova phase. — J. Rouch : Researches on shoals with 

 the aid of the divergent drag. This instrument, 

 invented by Admiral Ronarch during the War for 

 removing submarine mines, has been successfully 

 applied to the detection of submerged rocks in the 

 neighbourhood of the port of Brest. — Rene Lucas : 

 Magnetic moments of rotation and molecular magnetic 

 orientation. — R. Ledoux-Lebard, A. Lepape, and A. 

 Dauvillier : The use of hcav)^ gases in radio-diagnosis. 

 Radiographs of a frog, before and after breathing 

 krypton, show that this gas is as opaque to X-rays 

 as the tissues of the animal. — L^on Guillet : The 

 electrical resistance of commercial aluminium. The 

 purest commercial aluminium has a specific resistance 

 of 2 • 8 micro-ohms, and this increases with the amount 

 of impurities. Silicon appears to cause a greater 

 increase of resistance than iron. Mechanical treat- 

 ment has only a slight effect on the resistance. — W. 

 Kuhn : The decomposition of ammonia by ultra- 

 violet light and the law of photo-chemical equivalence. 

 The number of quanta absorbed per molecule of 

 ammonia is between 2 and 2-5 : this number is 

 increased as the light is made more nearly mono- 

 chromatic and is independent of the pressure and, 

 in the interval 10° and 20°, of the temperature. — 

 Pierre Bedos : Ortho-cyclohexyl-cyclohexanol. This 

 is prepared, with good yield, by the interaction of 

 cyclohexcne oxide and cycfohexyl magnesium 

 chloride. Only one of the two possible stereoisomers 

 is obtained : other methods of preparation of this 

 alcohol have given a mixture of the two isomers. — 



