July 6, 191 6] 



NATURE 



395 



suspensions of rigid particles at different rates of 

 shear. This investigation was undertaken with a 

 view of testing the Einsteln-Hatschek formula at 

 variable rates of shear. According to this formula the 

 viscosity of a suspension of rigid spherical particles 

 grows in linear ratio with the aggregate volume of 

 suspended particles, and is independent of their size, 

 so long as the latter conforms to Stokes's formula. 

 The suspension chosen was one of rice starch of 

 0003 mm., and less, diameter, in a mixture of carbon 

 tetrachloride and toluene having the same specific 

 gravity. The results of the investigation are : — (i) 

 The viscosity of a suspension is a function of the rate 

 of shear, and increases as the latter decreases, the 

 difference being more marked at higher concentrations ; 

 (2) for all rates of shear the viscosity of the suspension 

 increases more rapidly than the aggregate volume of 

 suspended matter ; (3) for any one rate of shear the 

 relative viscosity of a suspension, i.e. its absolute 

 viscosity divided by the absolute viscosity of the 

 medium at the same rate of shear, also increases more 

 rapidly than the percentage of suspended matter, the 

 divergence from the linear increase demanded by the 

 formula becoming less as the rate of shear becomes 

 greater, so that a linear law may possibly hold good 

 at rates of shear higher than those attainable in the 

 present apparatus without turbulence. The general 

 conclusion is that the assumption on which the 

 Einstein-Hatschek formula is based, viz. non-inter- 

 ference between adjoining particles, is not tenable in 

 the case of suspensions containing between 2 and 6 per 

 cent, of suspended matter. — Dr. A. GriflBths and others : 

 A correction of some work on diffusion. When salt 

 diffuses through water, in general there must be a 

 movement of the water due to volume-changes asso- 

 ciated with variations in concentration. In the papers 

 to which the recalculation refers reference was made 

 to the velocity of the liquid or solution ; but what was 

 meant bv the velocity of the liquid was not explained. 

 The author now deals with the velocity of the water- 

 component of the solution, to which a clear mathe- 

 matical meaning can be given. 



Royal Microscopical Society, June 21. — Mr. E. Heron- 

 Allen, president, in the chair. — Miss G. Lister : The 

 life-history of Mycetozoa, with special reference to 

 Ceratiomyxa. The author referred to the work of 

 Dr. Jahn, of the Berlin University, proving that the 

 amoebulae produced by division of the swarm-spores 

 united in pairs as gametes to produce zygotes, from 

 which the plasmodia grew. The nuclei of the zygotes 

 had twice as many chromosomes as the nuclei of the 

 gametes. In Ceratiomyxa Dr. Jahn was the first to 

 observe the division of nuclei in the young sporo- 

 phores prior to spore-formation ; this was found to be 

 a reduction division, and took place during the " net- 

 wx)rk " stage of the maturing sporophore. To illus- 

 trate these observations, lantern slides taken from the 

 preparations lent by Dr. Jahn were shown on the 

 screen, as well as a series of slides showing the more 

 striking forms of sporangia met with among the 

 Mycetozoa. 



Paris. 



Academy of Sciences, June 19.— M. Camille Jordan in 

 the chair. — G. Bigourdan : Honor^ Gaultier and some 

 confusion which has arisen concerning him. — G. 

 Bigourdan : The propagation of sound to a great dis- 

 tance in the open air. It is known that intense sounds, 

 produced by explosions, are not regularly propagated 

 round the source, but that there are zones of silence and 

 zones in which the sound is heard. The cannonade at the 

 front offers an opportunity for the experimental study 

 of this phenomenon, and a plan is outlined for its 

 systematic study. — H. Le Chatelier : The maximum 



NO. 2436, VOL. 97] 



solubility of calcium sulphate. A reply to some 

 criticisms of M. Colson. — A. ChanTcau : The precau- 

 tions necessary in the study of tuberculosis in i>ersons 

 employed in Parisian wine-bars. A reply to the views 

 expressed by M. Landowz}'. The author maintains 

 that tuberculous infection is independent of alcoholism. 

 — A. Versclialfel : A new method for the study of the 

 graduations of a circle. — R. Garnier : Study of the 

 general integral of equation (VI.) of M. Painlev^ in 

 the neighbourhood of its transcendant singularities. — 

 E. Baticle : The pressure exerted by a pulverulent mass 

 with a free plane surface on a sustaining wall. — 

 S. Posternak : The isomers T;.^ and Tveof stearolic 

 acid. Only four of the sixteen possible isomers of the 

 normal chain acetylenic acids, CH-jjOj, have up to 

 the present been described. The preparation and pro- 

 perties of two additional isomers are described in the 

 present paper. — M. Dalloni : The marine Bartonian in 

 the Pyrenees. — M. de Lamothe : The ancient outlines 

 of the coast of the basin of the Somme, and their con- 

 cordance with those of the western Mediterranean. — 

 E. Belot : The asymmetr\^ of the Pacific, the law 

 of the antipodes, and the general profound forms of 

 the earth in the hypothesis of a primitive southern 

 deluge. — B. Galitzine': The localisation of the epicentre 

 of an earthquake. The author recently developed a 

 method for fixing the position of the epicentre of an 

 earthquake from observations at a single station. 

 Since this method has been adversely criticised, the 

 records at the Pulkovo Observatorj- have been ex- 

 amined, and in 18 per cent, of the shocks registered 

 the epicentre could be localised. — G. Bonrguignon : The 

 measurement of resistances by discharges of con- 

 densers, using a sensitive milliammeter as a ballistic 

 galvanometer. For physiological purposes, the 

 method gives a maximum error of 4 per cent. — A. Ch. 

 Hollande : The anti-coagulating power of acid aniline 

 dves towards albuminoid materials. Acid aniline dyes 

 combine with albuminoids forming coloured acido- 

 albumens; these are not coagulated at 100° C, nor 

 even after twenty minutes in an autoclave at 120° C. 

 — M. Steppanides : A colorimetric method used by 

 the Romans for testing drinking water. Claim for 

 priority against M. Trillat. 



Washington, D.C. 

 National Academy of Sciences, May (Proceedings No. 5, 

 vol. ii.).— W. Hull and Marion Rice : The high- 

 frequency spectrum of tungsten. The authors show 

 two photographs of the spectrum of X-rays taken in 

 the usual manner in a rock-salt crystal. They also 

 give figures which show the ionisation current as a 

 function of the angle of incidence. A comparison with 

 previous results obtained by others is sketched. — R. L. 

 Moore : The foundations of plane analysis situs. As 

 point, limit-point, and regions (of certain t}-pes) are 

 fundamental in analysis situs, the author has set up 

 two systems of postulates for plane analysis situs based 

 upon these notions ; each set is sufficient for a consider- 

 able body of theorems.— E. B. Wilson and C. L. E. 

 Moore : A general theory of surfaces. Continuing the 

 work of Kommerell, E. Levi, and Segre, a theory of 

 two-dimensional surfaces in n-dimensional space is 

 developed bv the method of analysis outlined by Ricci 

 in his absolute differential calculus. — J. C. Hunsaker : 

 Dynamical stability of aeroplanes. A comparative 

 detailed study of two aeroplanes, one a standard mili- 

 tary tractor, the other designed for inherent stability, 

 is made for the purpose of reaching general conclu- 

 sions of a practical nature with respect to aeroplane 

 design. It appears that inherent stability (except at 

 low speed) can be obtained by careful design without 

 departing seriously from the standard type now in use. 

 — W. M. Davis : Clift islands in the coral seas. The 



