178 



NATURE 



[April 26, 19 17 



One of the most recent of these programmes is that 

 issued by the National Association of Head Teachers, 

 which has a membership of nearly 6000. Among- out- 

 standing recommendations of the head teachers are 

 the following : The age of exemption from full-time 

 attendance should not be lower than fourteen ; the 

 leaving age should be raised to fifteen and then to 

 sixteen, so soon as the necessary arrangeuiefiis can 

 be made ; no class should exceed forty on the roll, 

 and steps should be taken immediately to reduce them 

 to that limit, and there should be a fully qualified 

 teacher, trained and certificated, for each class. The 

 head teachers urge that a committee of competent 

 educationists should decide what subjects form a 

 necessary and basic part of every curriculum, up to, 

 say, twelve years of age, and the amount of time per 

 week which should be devoted to them, and what 

 subjects should be added in later years, attention 

 being directed to the needs of particular localities. 

 They insist, too, that the curriculum of every school 

 should include an amount of practical work sufficient 

 for the needs of the locality, and that a special room 

 for such work should be attached to each school. 

 They ask for a sufficient and suitable supply of 

 secondary schools of varying type and character, and 

 that every child with the requisite ability and inclina- 

 tion should be able to proceed to them. In large 

 elementary schools where children remain beyond 

 the age of fourteen, provision, the programme states, 

 should be made for instruction in drawing, music, 

 science, language, handicraft, and domestic economy. 

 So far as continuation schools are concerned, the 

 head teachers suggest that the employer ot any per- 

 son under eighteen should be required to enable him 

 or her to attend day continuation classes for not less 

 than eight hours a week, for which the employee 

 should be paid the ordinary rate of wages, and that, 

 in addition to this attendance at school," the hours 

 of labour per week should not exceed forty-eight. 



SOCIETIES AND ACADEMIES.' 



London. 

 Royal Society, March 29. — Sir J. J. Thomson, presi- 

 dent, in the chair —Sir William Abney : The fourth 

 colourless sensation in the spectrum sensation curve 

 when measured in the centre of the retina. At the 

 end of the last century the author carried out a large 

 series of observations on the luminosity of spectra 

 of very low density, but only lecently has he had an 

 opportunity of working some of them out. Some time 

 ago he published in the Phil. Trans, the three-colour 

 sensations which apparently suffice to account for 

 ■all the spectrum colours. There was a doubt if in 

 the mixture of the sensations to form these colours 

 some account ought not to be taken of the colour 

 sensation which appears when a coloured ray is 

 diminished in intensity for all colour to be absent 

 and only a colourless residue is left. The author 

 confines himself to the colours received on the centre 

 of the retina, for on the periphery other conditions 

 exist. The paper shows the method of observation 

 which was employed, and, discussing the results, the 

 author comes to the conclusion that the admixture 

 of the colourless sensation with the three-colour sen- 

 sations is so small as to be inappreciable, and that 

 the sensation curves given in his paper, to which 

 reference has been made, need no correction on this 

 account. — G. W. Walker : Magnetic inertia. It is 

 shown that a magnetised body may be expected to 

 possess magnetic inertia just as an electrified body 

 possesses electric inertia. In the case of a sphere of 

 radius a and matjnetic moment in the inertia for 

 acceleration parallel to the magnetic axis is 



NO. 2478, VOL. 99] 



2/5m^a-^C-*, and for acceleration perpendicular to 

 the magnetic axis ^/s^ni^a-^C-'^. (C is the velocity 

 of radiation.) The order of magnitude of this inertia 

 is considered in an astronomical as well as in an 

 atomic connection. — F. Tinker : The selective proper- 

 ties of the copper-ferrocyanide membrane. In the 

 present paper the selective properties of copper-ferro- 

 cyanide have been studied by measuring the change 

 in solution concentration which takes place when the 

 dry colloid is immersed in cane-sugar solutions of 

 various strengths. It is found that the sugar solu- 

 tions become stronger, owing to the fact that the 

 water and not the sugar is taken up selectively by 

 the ferrocyanide. The experimental results lead to 

 the hypothesis that a colloidal hydrate, Cu2FeCy6.3HoO, 

 is first formed, and that this colloidal hydrate then 

 takes' up still more moisture by adsorption. The 

 amount of adsorbed moisture taken up by the 

 colloid decreases as the strength of the solution in- 

 creases. It is also shown in the paper that the side 

 of a membrane in contact with pure water has a 

 greater moisture content than the side in contact with 

 sugar solution. This fact supports the hypothesis — 

 first advanced by Graham on experimental grounds — 

 that osmosis across a membrane takes place because 

 pure water induces a greater moisture pressure and 

 concentration inside the membrane than the solution 

 does. — C. M. Williams : X-ray analysis of the crystal- 

 structure of rutile and cassiterite. — Dr. J. G. Leathern : 

 Discontinuous fluid motion. The subject of the paper 

 is the flow, with free stream-lines, of infinitely ex- 

 tended fluid past a finite obstacle with a sharp prow 

 and curved sides. The methods of Levi-Civita, Cisotti, 

 Villat, and Levy are compared with the writer's own 

 method, and translated into formulations by curve- 

 factors. 



Zoological Society, April 3.^ — Prof. E. W. MacBride, 

 vice-president, in the chair.— R. H. Burne : Notes on 

 some of the viscera of an okapi {Okapia johnstoni, 

 Lankester). The author described the anatomy of 

 the soft parts of various portions of this animal. 



Royal Meteorological Society, April 18. — Major H. G. 

 Lyons, president, in the chair. — E. G. Bilham : The 

 diurnal variation of atmospheric pressure at Benson, 

 Oxon., during 1915. By means of hourly measure- 

 ments of traces from the Dines float barograph at 

 Benson Observatory, the mean diurnal inequalities 

 for each calendar month of 1915, and for the year, 

 have been obtained and submitted to Fourier analysis. 

 With the exception of the amplitude of the 24-hourly 

 oscillation, the mean results f6r the year are in good 

 agreement with the normal values for Kew and 

 Oxford. A discussion of the probable errors to which 

 the results are liable leads to the conclusion that the 

 first order term is the most susceptible to casual error 

 due to non -periodic changes of pressure. It is, more- 

 over, well known that this term is largely dependent' 

 on local meteorological and geographical conditions, 

 so that considerable fluctuations are to be expected. 

 Comparing the Benson results for individual months 

 with the normal values for Kew, it is found that 

 relatively high values of the diurnal range are asso- 

 ciated with high values of the amplitude of the 24- 

 hourly oscillation. The second and third order ampli- 

 tudes show similar seasonal variations at the two 

 stations.^Lieut. C. D. Stewart : Atmospheric elec- 

 trical phenomena during rain. A preliminary investi- 

 gation has been made into the values of the potential 

 gradient occurring during rain. It is found that 

 maximum values occur in summer and minimum 

 values in winter. The maximum fine-weather values 

 occur in winter. The form of the diurnal variation 

 of rain potential gradient is still uncertain, although 



