November 21, 19 12] 



NATURE 



349 



The Imperial Education Conference, at its meeting 

 last year, recommended that there should be appointed 

 in connection with that conference an advisory com- 

 mittee consisting of the accredited agents in London 

 of the several Governments coricerned, together with 

 representatives of the Colonial Office, the India Office, 

 the Board of Education, the Scotch Education Depart- 

 ment, and the Irish Office. The functions of the 

 committee as recommended by the conference were to 

 be to keep itself acquainted with the progress of any 

 courses of action that the conference had recom- 

 mended, to facilitate that progress when necessary 

 by communicating with the Governments concerned, 

 and to consider such proposals as might be submitted 

 for the agenda of any future meetings of the confer- 

 ence. The following representatives have been 

 nominated by the various Governments and depart- 

 ments concerned to serve on the committee : — Mr. 

 L. A. Stlby-Bigge, C.B., Board of Education; Dr. 

 H. Frank Heath, C.B., Board of Education ; Sir John 

 Siruthers, K.C.B., Scotch Education Department; Dr. 

 W. J. M. Starkie, Irish Government; Sir H. W. Just, 

 K.C.M.G., Colonial Office (Dominions Division); Mr. 

 J. F. N. Green, Colonial Office (Crown Colonies); 

 Sir Theodore Morison, K.C.I.E., India Office; the 

 Right Hon. Lord Strathcona and Mount Royal, 

 G.C.M.G., G.C.V.O., Dominion of Canada; the 

 Right Hon. Sir G. H. Reid, P.C, G.C.M.G., Com- 

 monwealth of Australia ; the Hon. Thomas Mackenzie, 

 Dominion of New Zealand ; Mr. T. Slingsby Night- 

 ingale, Union of South Africa; Mr. T. A. Coghlan, 

 New South Wales ; the Hon. Sir John Taverner, Vic- 

 toria ; Major Sir Thomas Robinson, Queensland ; 

 the Hon. A. A. Kirkpatrick, South Australia; Mr. 

 Cyril Jackson, Western .Australia; the Hon. Sir John 

 McCall, Tasmania. The Board of Education has 

 placed at the disposal of the committee the services of 

 Mr. W. W. Tir-n-'I, .V^^i^tmt D^T-pctor of Special 

 Inquiries and Reports, to act as honorary secretary. 



SOCIETIES AND ACADEMIES. 

 London. 

 Royal Society, November 7. — Sir Archibald Geikie, 

 K.C.B., president, in the chair. — Louis V. King : The 



scattering and absorption of light in gaseous media, 

 with applications to the intensity of sky radiation. 

 The analysis of the present investigations seems to 

 support the view that, at levels above Mount Wilson, 

 molecular scattering is sufficient to account completely 

 both for attenuation of solar radiation and for the 

 intensity and quality of sky radiation. Even at sea- 

 level the effect of "atmospheric dust" can be taken 

 into account in a simple manner in formulce for 

 absorption and scattering. — Dr. P. E. Shaw : A 

 standard measuring machine. — E. M. Stubbs and Dr. 

 E. B. R. Prideaux : A spectro-photometric comparison 

 of the emissivitv of solid and liquid gold at high tem- 

 peratures with that of a full radiator, (i) The emis- 

 sivitv of solid and liquid gold at high temperatures, 

 relative to the emissivity of a full radiator at the same 

 temperatures, has been measured throughout the visible 

 spectrum. (2) A sharp discontinuity in the emissivity 

 takes place at the melting point, the liquid gold 

 emitting more strongly than the solid in the red and 

 yellow, and less in the extreme blue. The shape of 

 the " relative emissivity " curves is quite different in 

 the two cases. (3) The curve of " relative emissivity " 

 of solid gold at high temperatures is similar to that 

 of absorptivity at low temperatures as determined from 

 reflectivity measurements; whether it is identical, in 

 which case the temperature coefficient of the absorp- 

 tivity would be nil, could not be absolutely determined, 

 owing to the change of structure which a polished 

 NO. 2247, VOL. 90] 



surface undergoes on heating. (4) No temperature 

 coefficient of "relative emissivity" could be detected 

 for the liquid metal through a range of more than 

 100°. (5) " Black body " temperatures of solid and 

 liquid gold at the melting point have been calculated. 

 (6) It has been shown that the general equation ex- 

 pressing the radiation of a selective radiator is of the 

 form 



Ev=/(A, T)6-iX-V-^-i'AT, 



which in the case of gold and other metals cannot be 

 reduced to the form of Wien's equation for a full 

 radiator with changed values of the constants. — C. 

 Smith : Optical properties of substances at the critical 

 point. — Hon. R. J. Strutt : Absorption of helium and 

 other gases under the electric discharge. Attempts to 

 repeat Berthelot's absorption of helium by carbon 

 disulphide under the influence of the silent discharge 

 have given absolutely negative results. Helium is 

 slightly absorbed by phosphorus under electric dis- 

 charge, though in much less quantity than nitrogen 

 or hydrogen. The absorption in the former case is 

 regarded as mechanical, in the latter as chemical. — 

 F. W. Aston : The discharge between concentric 

 cylinders in gases at low pressures, (i) The relations 

 between pressure, voltage, and the length of the 

 Crookes dark space in the discharge between concen- 

 tric cylinders take much the same form as those in the 

 discharge between parallel planes. (2) Curvature of 

 the surface of the kathode appears to have no influence 

 upon the rate of alteration of the length of the dark 

 space with change of current density, so long as the 

 latter is measured at the surface of the kathode. (3) 

 Ceteris fiaribus, the length of the dark space is greater 

 for a convex cylindrical surface than a plane, and for 

 a plane than a concave one. — F. W. Aston : The influ- 

 ence of the nature of the kathode on the length of the 

 Crookes dark space, (i) The relations between the 

 values of pressure, voltage, current, and the length of 

 the dark space are determined for plane kathodes of 

 manv different materials, and found to satisfy the 

 same form of equations as those previously given for 

 aluminium, the constants varying considerably. (2) 

 Rougfhness of the kathode surface does not appear 

 to affect the discharge, if the dimensions of the irregu- 

 larities are small compared with the length of the dark 

 space. (3) The length of the dark space is shown, in 

 the cases' examined, to be greatest for silver and least 

 for magnesium, the metals following the same order 

 as in the case of the kathode fall. "(4) The rate of 

 change of length of the dark space with change of 

 current density at the surface of the kathode seems 

 much the same for all kathodes. (5) Difficulties in the 

 wav of arriving at a satisfactory explanation of these 

 and other data connected with the dark space are 

 indicated and shortly discussed. — A. Campbell : The 

 determination of the absolute unit of resistance by 

 alternating-current methods.— .-X. Mallock : Some un- 

 classified properties of solids and liquids. This paper 

 suggests that many qualities of solids and liquids, 

 which, although well known and commonly recog- 

 nised, are not classified (qualities, for instance, such 

 as ductijitv and malleability), may be explained^ by 

 reference to the relations of the limits of the principal 

 elasticities of the substances. A real homogeneous 

 isotropic substance, whether solid or liquid, offers two 

 distinct kinds of resistance to deformation, viz., resist- 

 ance to alteration of volume and resistance to shear. 

 There are also two 'distinct and different limits to each 

 of these kinds of deformation — limits which cannot be 

 exceeded without causing rupture or permanent altera- 

 tion of the substance. When a strain involves both 

 I shear and alteration of volume, the behaviour and 

 ' properties of the strained material depend to a fjreat 

 ! extent on whether the limit of shear or the limit o' 



