542 



NATURE 



[June 23, 192 1 



tion from large areas.— F. C. Toy : The photographic 

 efficiency of heterogeneous light. Two possible laws 

 of action are discussed :—(i) All radiations composing 

 the heterogeneous beam may act simultaneously but 

 independently; and (2) all radiations may act simul- 

 taneously but not independently. The possibility of 

 testing the laws depends on the form of law connect- 

 ing the probability of a single grain of the photo- 

 f^raphic emulsion being made developable with the 

 intensity of the exciting light. The form of this law 

 proved experimentally by Slade and Higson is con- 

 sidered, and a result is deduced which can be tested 

 bv experiment. From the evidence obtained it is con- 

 cluded that over the spectral range used in the experi- 

 ments (A4350 to A4000) radiations of different fre- 

 quencies act simplv as a total amount even when a 

 difference in quality exists. 



Linnean Society, June 2. — Dr. A. Smith Woodward, 

 president, in the chair.— Prof. W. Garstang : Haeckel's 

 biogenetic law : A theory of ancestral heredity. 

 Ancestors created, heredity transmitted, and develop- 

 ment repeated the order of creation. .\ generalised 

 recapitulation of the essential grades of ancestral 

 structure was also possible without involving succes- 

 sive adult images in the ontogeny. The morphological 

 test to apply to these theories was whether the stages 

 of ontogeny resemble successive adult organisations 

 more closely than the corresponding formative stages 

 of ancestral ontogeny. This test was invariably in 

 favour of the "persistence theory" of recapitulation 

 and against the theory of accelerated adult incorpora- 

 tions. 



Aristotelian Society, June 6. — Prof. Dawes Hicks, 

 vice-president, in the chair. — Dr. Dorothy Wrincli : 

 The structure of scientific inquiry. In the earlier 

 stages of empirical generalisations results of a general 

 character are built up and applied by means of the 

 forms of reasoning employed in probability inference, 

 viz. induction and analogy. In the more advanced 

 stage the aim of science is to arrange the general 

 propositions which cover, as particular cases, the 

 phenomena of which we are aware in such a way 

 that the phenomena of the world are deducible from 

 the smallest possible number of assumptions. Logical 

 necessity alone can knit together theories and the 

 experimental results which go with them. It is found 

 that logic consists of relations between sets of pro- 

 perties. The general study of the formal and abstract 

 properties is at the foundation of the great advance 

 in modern science. In particular the process of irue 

 analogy, whereby the problems of electrostatics, cur- 

 rent electricity, thermodynamics, and hydrodynamics 

 are simultaneously solved, is of the utmost import- 

 ance. 



Paris. 



Academy of Sciences, Mnv :^o. — M. Georges Lemoine 

 in the chair. — A. Blonde! : The application of distri- 

 buted statical transformers to the regulation of high- 

 voltage mains. — B. Jekhowsky : Bessel's functions with 

 two variables. — E. Kogbetliantz : The developments of 

 Jacobi. — Et. Delassus : A consequence of the laws of 

 friction. — J. Vallot : Diffuse radiation at Mont Blanc 

 Observatory compared with that at lower altitudes. 

 The stations chosen were at the altitudes 50, 1 100, 

 2500, 4250, and 4350 metres above the sea. A table is 

 given showing mean values for the observations on 

 several exceptionally fine days. The diffuse radiation 

 diminishes at first up to an altitude of 2500 metres, 

 and then at the top of Mont Blanc increases suddenly 

 to nearly double. This is explained by the intense 

 radiation of the snow. — .\. Schaumasse : Observations 



NO. 2695, VOL. 107] 



of the Dubiago comet (19214) made with the bent 

 equatorial at the Observatory of Nice. Positions given 

 for May 24 and 25. The comet was of the 11-5 mag- 

 nitude, and showed a slight central condensation — 

 (i. Bruhat and Mile. M. Hanot : The Lippich black 

 fringe and the precision of [wiarimetric measurements. 

 From calculations and exi>eriments cited it is con- 

 cluded that even after choosing the best position of the 

 line of separation it is not possible, with Nicol prisms, 

 to measure a rotation of the order of 20° with an 

 error less than one minute. With more intense sources 

 of light, such as the mercury arc, this error can be 

 reduced by one half. — R. Boulouch : The problem of 

 achromatism of thick-centred systems.— M. Rothe : 

 Radiogoniometry and atmospheric influences. Earlier 

 observations (1914) had shown that in the course of 

 the day Hertzian waves were absorbed bv the atmo- 

 sphere. The present research was an attempt to find 

 out whether, in addition to absorption, the direction 

 of the waves was modified. The deviations observed 

 were of the order of the experimntal error, and con- 

 sequently no certain conclusion could be drawn as 

 to the cause of the small variations observed.— G. 

 Dejardin : The ionisation of argon by slow electrons. 

 .An account of the application of the lamp with three 

 electrodes, of the type commonly employed in military 

 wireless telegraphy, to the determination of the ionisa. 

 tion potential of argon. The value found was 15 

 volts.— .\. Dauvillier : The T. series of uranium and the 

 principle of combination in X-ray spectra. — .\. Cabrier : 

 .\n automatic lighting and extinguishing apparatus 

 for street gas lamps. .\n account of an apparatus 

 which has been in use for eight years, "and comparison 

 with a similar apparatus recently described bv Paul 

 Bernard and Barbe.— V. Auger : ' Double catalysis oi 

 vanadic acid and hydrogen peroxide. Vanadic acid 

 may be reduced to vanadyl sulphate or oxidised to 

 pervanadic acid by hydrogen peroxide in the presence 

 of sulphuric acid, the direction of the change being' 

 conditioned by the amount of acid present. — Mile. 

 Wolff : Furfuralcamphor and some of its derivatives. 

 .\n account of the product of condensation of furfural 

 with camphor and the substances obtained bv reduc- 

 tion. — M. Manolesco : The action of ethylmagnesium 

 bromide on dibenzylidene cyrZohexanone and 7-methvl- 

 cydohexanone. — G. Tanret : The influence of ammo- 

 nium mohbdate on the rotatory power of some 

 sugars. Changes in the rotatory power produced by 

 adding solutions of ammonium molybdate to solutions 

 of xylose, glucose, rhamnose, arabinose, galactose, 

 sorbose, laevulose, and mannose are given. No change 

 was produced in the rotation of saccharose, maltose, 

 trehalose; lactose, melezitose, raffinose, stachyose, 

 inulin, quercite, and inosite. In the cases of the 

 suerars whose rotation was affected, some evidence is 

 adduced of the formation of a compound between the 

 sugar and the molybdate. — F. Bourion and Ch. 

 Courtois : The formation of Julin's chloride in the pre- 

 paration of electrolytic chlorine. In certain casos 

 acicular crystals were found in considerable quantities; 

 in electrolytic cells. These have been collected, purified, 

 and shown to consist mainlv of hexachlorobenzene. — F. 

 Roman and P. de Brun : The structure of the .Alpine 

 chain. — Mile. G. Cousin : The individual variations of 

 Psiloceras pJanorbis. — M. Flajolet : The strong mag- 

 netic perturbation of Mav 14-1^, 1921. An account 

 of the mafifnetic disturbance as shown on the recording 

 instrumonts at the Lyons Observatory. The needle 

 was at times beyond the limits of rep-istration, and 

 all thp telei?raphic circuits were seriously affected. — G. 

 Dupont : Contribution to the study of the acid con- 

 stituents of the secretion of the maritime pine. 



