746 



NATURE 



[February 3, 192 1 



Societies and Academies. 



London. 

 Geological Society, January 19. — Mr. R. D. Oldham, 

 president, in the chair.— Dr. L. J. Wills and B. Smith : 

 The Lower PalEEOzoic roclis of the Llangollen dis- 

 trict, with especial reference to the tectonics. The 

 general sequence of rocks and details of their com- 

 ponents in various localities are given. The Lower 

 Palaeozoic rocks are, in the main, folded on approxi- 

 mately east-and-west axes, to which the cleavage and 

 some of the major faults are closely parallel in direc- 

 tion. The folding and part of the faulting are 

 Devonian, and appear to have set up torsional stresses 

 affecting a greater area than that considered here. 

 The concertina-folding in the synclinoria appears to 

 be related to the tough anticlinal nodes of the northern 

 Ordovician outcrops. The master-faults separate 

 blocks of country which appear to have been displaced 

 laterally in post-Carboniferous times. The minor 

 faults appear to be adjustments that allow the strata 

 to comply with torsional stresses. 



Paris. 

 Academy of Sciences, January 3. — M. G. Lemoine in 

 the chair. — E. Picard : Certain functions connected 

 •with closed surfaces. — P. Termier and L. .loleaud : 



The age of transport phenomena in the region of 

 Avignon. — L. Fabry : The use of geocentric latitudes 

 for facilitating the identification of the minor planets. 

 Two minor planets were notified in Circular 138 of the 

 Marseilles Observatory which appeared to be new. 

 The author has applied the method of geocentric lati- 

 tudes to the photographic observations, and shows 

 that one of these is identical with Mnemosyne (57). — 

 R. de Forcrand : The melting point of heptane and 

 the law of alternation of melting points. Hexane 

 gave a melting pointpf — g3-5°C.,as against -95°C. 

 found by Guttmann, and octane -57-4° C. (Guttmann 



— q8-2° C). It has been shown that the melting 

 points of many series of carbon compounds show an 

 irregular-toothed curve, such that in passing from a 

 compound with an even number of carbon atoms to 

 the next higher homologue with an odd number the 

 melting point fell. The data for the C, to C, paraffin 

 hydrocarbons appeared to give jin exceptional curve, 

 but with the substitution of —57-4° C. for the 



— 98-2° C. of Guttmann the curve becomes normal, 

 and would indicate —94° C. as the melting point of 

 heptane. Pure heptane was prepared and found to 

 have a melting point of —94-7:;° C. — H. Parenty : The 

 reconstitution of certain invisible details of old pic- 

 tures. With reference to a recent paper bv \. Chdron 

 on the use of radiography for the recognition of 

 ancient pictures, the author recalls a paper published 

 in iqi3 in which photography was used for the same 

 purpose, and mentions two cases in which his con- 

 clusions based on ordinnrv photographs have been 

 confirmed. — P. Vuillemin : Th" aberrations of floral 

 symmetry. — M. Angelesco : Certain completelv in- 

 teerable linear differential equations. — K. Petot : 

 Shocks in the change-Sears of motor-cars. — M. 

 Dumanois : The determination of a criterion of general 

 fatigue in internal-combustion motors. K discussion 

 of a formula for the factor of safety in the construc- 

 tion of internal-combustion motors, with special refer- 

 ence to Diesel engine-;. — H. Corblin : A compressor 

 with a membrane. The gas compressor described 

 and illustrated has, in effect, a liouid piston, with an 

 elastic metallic membrane seoaratinsj the liouid and 

 the f*as being compressed. The compression is nearlv 

 isothermal, and air can be carried from atmospheric 

 pressure to 100 kg. per so. cm. at one step. — J. 



NO. 2675, VOL. 106] 



tiuUlaume : Observations of the sun made at the 

 Lyons Observatory during the third quarter of 1920. 

 Observations were made on eighty-eight days during 

 the quarter and the results are shown in three tables, 

 giving the number of spots, their distribution in lati- 

 tude, and the distribution of the facula; in latitude. - 

 L. \. Herdt and R. B. Owen* : The direction of 

 ships at the entrance of ports and channels by a 

 submerged electric cable. .An account of experiments 

 carried out in Canada in 1904, and suggestions for the 

 development of the method. — M. Liinard : Scalar and 

 vector potentials due to the motion of electric charges. 

 A formula recently developed by Ander.son (Phil. Mag., 

 August, 1920) is not in agreement with one given by 

 the author in 1898. .\ mathematical investigation of 

 the cause of the discrepancy is given. — G. Ferrii, 

 R. Jouaust, R. Mesny, and A. Perot : Studies in radio- 

 goniometry. L'nder normal conditions the direction 

 of the electromagnetic waves in wireless telegraphy 

 can be determined within 1°, but under certain condi- 

 tions the azimuth of a transmitting post varies 

 capriciously, and at certain times during the day no 

 position can be found. These effects have been care- 

 fully studied, but although there is some evidence of 

 a seasonal influence the exact cause of these devia- 

 tions has not yet been elucidated. — A. Chiron : The 

 radiography of pictures. In the preparation of the 

 canvas at the present time white lead is used, whilst 

 in carlv times calcium carbonate and wax were pre- 

 ferred. These differ markedly in transparency to the 

 X-rays, and the materials of old and modern paints 

 also show differences in this respect. Hence radio- 

 graphy mav serve to distinguish between old and 

 modern pictures, and in certain cases can bring out 

 restorations. — E. Rengade : Saline double decomposi- 

 tions and the phase rule. It is shown by experirnent 

 that if a mixture of sodium nitrate and ammonium 

 chloride is treated with a quantitv of water insufficient 

 for complete solution, crystals of sodium chloride are 

 formed. This is opposed to the conclusion arrived 

 at bv M. Raveau in a recent communication. — G. 

 Denigis : Remarks on a recent note by M. A. Bolland 

 on the microchemical reactions of iodic acid. A 

 claim for priority.— A. Kling and D. Florentin : The 

 properties and constitution of the group (CO.Cl.l. 

 The complete substitution of hydrogen by chlorine in 

 the group — OCH, gives rise to abnormal properties. 

 From its reactions it has a modified structure and 

 behaves as phosgene plus chlorine. — C Dufral»»e : 

 The othvlene isomerism of the <.>-bromostyrolenes. 

 Both these stereo-isomers are liquids at the ordinary- 

 temperature, and differ in colour and smell. An 

 account is given of their reciprocal transformations. — 

 J. Durand : The action of the alkaline metals on the 

 ether oxides. It has hitherto been supposed that 

 ordinary ethvl ether and its homologues are without 

 action on sodium and the other alkaline metals, but 

 the author shows that this is not the case. Details 

 of the reaction between sodium (cr the liquid alloy 

 of sodium and potassium) on ethvl and isoamyl ethers, 

 veratrol, ethvlbenzyl ether, and diphpnyl ether are 

 given. The exact mechanism has still to be worked 

 out. — F. Grandjean : The existence of oouidistant dif- 

 ferentiated planes normal to the optic axis in liquid 

 crystals. — P. Negris : The glacial osrillations of the 

 Quaternary period and the corresponding movements 

 of the lithosphere. — E. Chaput : Observations on the 

 ancient alluvium of the Seine. — E. Mesnard : Con- 

 tribution to the history of earthquakes. — P. Lesage : 

 Snline plants and period of anomalies. — G. Nicola* : 

 Contribution to the study of the mechanism of the 

 fertilising action of sulphur. Sulphur increases the 

 assimilation of carbon from the air bv the action of 

 chlorophyll.— M. Barlot ; A new reagent for Lactarius 



