June 14, 191 7] 



NATURE 



19 



degree of coincidence between the actual positions of 

 the whorls on .the spicule and the positions which 

 would be occupied by the nodes in a vibrating free-free 

 rod of shape similar' to that of the shaft of the spicule 

 at the moment when the nodes are beginning to 

 develop (i.e. at the critical stage). The general 

 problem is that of the nodes in a rod composed of two 

 equal portions, each formed by the rotation of the 

 curve ya:x" between x = o and x=^l about its axis, and 

 the positions of the nodes are expressed as functions 

 of the index n by the interpolation formula. All the 

 spicules examined correspond ven,- closely ' with this 

 law of shape for values of n between \ and i. Details 

 of ten cases at or near the critical stage are given in 

 the paper, and the conclusion is arrived at that the 

 positions of the whorls, although subject to slight indi- 

 vidual variations due to various disturbing factors, 

 agree so accurately with the theoretical positions of the 

 nodes as to leave little doubt as to the influence of 

 transverse vibrations in determining them. An 

 efficient cause of such vibrations may be found in the 

 water currents which circulate with considerable force 

 through the canal system of the sponge. ^Prof. J. W. 

 Nicholson : The lateral vibrations of bars of variable 

 section. The paper contains a discussion of the lateral 

 vibrations of a bar composed of two equal halves and 

 free at each end. Each half consists of a portion of the 

 solid generated by the revolution of the curve y = A.r" 

 about its axis, and the fundamental frequencies and 

 positions of the corresponding nodes are investigated 

 for various values of n between o and i. 



Physical Society, Mav 25. — Mr. W. R. Cooper, vice- 

 president, in the chair. — C. C. Paterson, J. W. T. 

 Walsh, and W. F. Higgins : An investigation of radium 

 luminous compound. The paper contains the results 

 of measurements made on various samples of radium 

 luminous compound during the last two years." Deter- 

 minations of the brightness of the compound in powder 

 form and when made up into paint, and also after the 

 application of the paint to instrument dials, were 

 carried out ; and curves are given showing the rates 

 of decay of luminosity. The radium contents of the 

 compounds were determined by comparison of their 

 7-ray activities with that of a preparation of pure 

 radium bromide, which is periodically compared with 

 the British radium standard. The various precautions 

 which have to be observed and the corrections which 

 have to be applied in making the various determina- 

 tions are explained, and the considerations which 

 should govern the proportion of radium emploved for 

 practical purposes are discussed. — F. J. W. Whipple : 

 The resistance to the motion of a lamina, cylinder, or 

 sphere in a rarefied gas. The investigation is carried 

 out on the assumptions that the free-paths of the 

 particles of the gas are long compared with the dimen- 

 sions of the moving body, and that the motion, relative 

 to the body, of the particles which rebound from it 

 depends only on its temperature. It is shown that if 

 V, w be the components of velocity perpendicular to the 

 surface of a lamina nnd parallel thereto, the corre- 

 sponding components of the resistance are 



(4 + -'^/7;> an ^/1-A 



where V is the standard (root-mean-square) speed of 

 the gas-particles and p is the gas-pressure. The re- 

 sistance to the motion of a cylinder or a sphere is 

 found to differ verv slightly from the resistance to a 

 lamina occuoying the central section. The formulas 

 are applicable to the problem of the damping of the 

 oscillations of a svstem suspended in a rarefied gas.— 

 Prof. C. H. Lees : The effect of stretching on the 

 thermal conductivity of wires. 



NO. 2485, VOL. 99] 



Paris. 

 Academy of Sciences, M^y 21. — M. A. d'Arsonval in 

 the chair.— G. A. Bouleager : Batrachians belonging to 

 the genus Euproctus, their ethological and phylogenic 

 relations. — M, P. A. Dangeard was elected a member 

 in the section of botany in the place of the late 

 R. Zeiller. — P. Fatou : Rational substitutions. — L. 

 Decombe : The influence of temperature on electro- 

 capillary phenomena. An application of the second 

 law of thermodynamics to electrocapillary phenomena, 

 utilising the numerical results obtained by W. A. 

 Vining and by M. Gouy.— M. and Mme. A. Laborde : 

 Remarks on a note of MM. Debierne and Regaud on 

 the use of the radium emanation condensed in sealed 

 tubes. For clinical woik MiM. Debierne and Regaud 

 have proposed to express the energy given out in terms 

 of the quantity of emanation destroyed during the 

 application. The authors suggest that the mean quan- 

 tity of emanation present in the sealed tube during the 

 time of application gives an equally exact measure of 

 comparison betweeii the two methods of utilising the 

 energv of radium. Actual cases are worked out 

 according to both modes of expression. — MM. Massol 

 and Faucon : The absorption of the ultra-violet radia- 

 tions by the iodine derivatives of methane. Details of 

 the absorption bands produced by tetraiodomethane, 

 iodoform, methylene iod'de, and methyl iodide.— Ed. 

 Chaavenet : The zirconyl bromides The only definite 

 compounds isolated were ZrBr4.ZrOBr,.8H20 and 

 ZrOBr,.3.5H;0.— A Valeur : An anomaly in the solu- 

 bility of sparteine. An aqueous solution of sparteine 

 becomes turbid when the temperature is slightly raised, 

 and this effect is still more marked in dilute solutions 

 of sodium carbonate. In the latter case the relation 

 between the concentrations in sparteine and the tem- 

 perature of turbidity formation has been determined, 

 and between certain limits of concentration the curve 

 expressing the results is a straight line. A method for 

 determining this alkaloid can be based on these experi- 

 ments. J.'Bougault: Acidylsemicarbazides and acidyl- 



semicarbazic acids. The 'author attributes the con- 

 stitution, CeH3.CO.NH.NH.CO.NH,, to the product 

 obtained by the action of sodium carbonate and iodine 

 on the semicarbazone of phenylglyoxylic acid, whilst 

 for the isomer produced by the action of benzoic 

 anhydride upon semicarbazide chlorohydrate the for- 

 mul'a C«H,.C(OH) : N.NH.CO.NH, is suggested as 

 most probable. — G. Mouret : The existence of a zone of 

 crushed rocks, about 200 kilometres long, in the 

 western region of Central French massif.— Ph. Glan- 

 geaud : The elements of the relief of the volcanic massif 

 of the Monts-Dore.— L. Ballit : The determination of 

 the densitv of air as a function of the altitude. The 

 method is' based on the measurement of the rate of 

 ascent of a free balloon, which need not be recovered. 

 The heights are estimated by simultaneous observa- 

 tions by two observers on the 'ground.— C. Sanvagean : 

 \ new type of alternation of generations in the brown 

 algje {Dictyo siphon foeniculaceiis).— Em. Bonrquelot, 

 M. Bridel, and A. Anbry : The crystallisation and pro- 

 perties of a ^-monoglucoside of 'glycerol obtained by 

 biochemical synthesis. The synthesis of this glucoside 

 has been described in an earlier paper (1915)- ^Y 

 solution in absolute alcohol, and partially precipitating 

 with ether and then allowing to stand at a temperature 

 below 6° C. for twent>'-one months, the substance has 

 been obtained in the crystalline state. Details are given 

 of its rotatorv power and chemical and biochemical 

 hvdrolvsls. This Is the first glucoside of glycerol to be 

 obtained in a cr\-stallised state.— M. Lievre : Stereo- 

 radioscopy. The apparatus described has been used 

 with success In the Army Medical Service.— J. Amar : 

 The origin and prophylaxy of heat stroke. Heat stroke 



