June if, 1918] 



NATURE 



339 



SOCIETIES AND ACADEMIES. 

 London. 

 Royal Society, June 13.— Sir J. J. Thomson, presi- 

 dent, in the chair. — Admiral Sir Henry Jackson : Ex- 

 periments on the effect of the vibration of a stretched 

 wire forming part of a closed electric circuit. A 

 large thermo-microphone consisting of a long loop of 

 wire warmed by an electric current, subjected to vibra- 

 tion produced by sound-waves, continued to respond 

 to and record the effect of the vibration in suitable 

 receiving apparatus after the electric battery had been 

 cut out of its circuit, and When the wire was at the 

 same temperature as the air. This result of the wire's 

 vibration could not, therefore, be solely attributed to 

 the wire being maintained at a different temperature 

 from that of the surrounding air by an electric current 

 in it. The response to the sound and other vibrations 

 was generally recorded by means of an amplifier and 

 telephones. Experiments were carried out to elucidate 

 the cause of the phenomenon. It is shown that resonance 

 plays an important part. No definite conclusions, 

 however, can yet be drawn as to the quantitative effect 

 of altering tension or length of wires, or their dis- 

 placement, on current generated, nor does the energy 

 expended in producing vibration appear to be pro- 

 portional to the effect produced, unless resonance is 

 present.— A. MaUock : Note on the effect of wind- 

 pressure on the pitch -of organ-pipes. The fact that 

 the pitch of an organ-pipe is to some extent dependent 

 on the pressure of the wind supply is well known, 

 but no satisfactory explanation of this dependence has 

 hitherto been offered. In the present note some ex- 

 periments on the subject are described in which water 

 instead of air was used as the oscillating fluid. It is 

 shown by photography that the lateral motion of the 

 fluid jet or lamina which maintains the oscillation is 

 always in the direction of the oscillating flow, and also 

 that the oscillation is not (or only very feebly) main- 

 tained unless the jet breaks up into eddies before 

 striking the " lip " of the pipe. It is suggested that 

 the rise of pitch which occurs when the jet velocitv is 

 increased depends on the jet acting as an injector. 

 Part of the fluid belonging to the oscillating flow 

 becomes involved in the eddies of the jet, and is 

 accelerated bv energy drawn from this source, thus 

 diminishing the amount of energy which would other- 

 wise have to be taken from the oscillating system. 

 In effect, this action reduces the oscillating mass, 

 and thereby increases the frequency. The results ob- 

 tained with the water oscillator are compared with 

 Lord Rayleigh's experiments on organ-pipes, and it 

 appears that the variation of frequency with the pres- 

 sure of the fluid supplv is similar in type in both 

 cases.— Dr. A. E. Oxiey : The diamagnetism of 

 hydrogen and the value of the magneton. 



Optical Society, June 13.— Prof. F. J. Cheshire, presi- 

 dent, in the chair.— H. Lee : A chart for finding the 

 number of lenses in, and size of, a block. The chart 

 shows by two series of intersecting curves the number 

 of lenses it is possible to place in. any ring of a block 

 (up to ten rings) when the maximum diameter of the 

 block, the diarneter of the lens, and the radius of 

 curvature to which the lenses to be worked are given. 

 Any case likely to arise in the workshop can be at 

 once determined by interpolation between the curves 

 shown. The diagrams exhibited are for the two cases 

 when the first rint? contains one lens and three lenses 

 respectively. The formulae from which the charts were 

 Calculated are given. — H. S. Ryland : The prevention 

 of filming in enclosed ontical instruments, (i) The 

 ''lining is indenendent of the nature of the glass; 

 the film itself is always alkaline ; (3) it is progres- 

 NO. 2539, .VOL. lOl] 



sive; (4) it is avoided by absolute cleanliness during 

 the assembling of the instrument, by taking care that 

 no soap or animal matter is left upon the glass sur- 

 faces, and that no volatile as water-bearing material 

 is used inside an enclosed instrument. — T. Smith : 

 Charts for assisting in the selection of suitable glasses 

 for cemented doublets. Use is made of two charts 

 sliding one over another in the manner in which a 

 slide-rule is used, one of the charts being transparent. 

 A single variable suffices to determine very approxi- 

 mately the numerical relation between the various 

 spherical aberrations for all cemented doublets made 

 from two given glasses. Chart No. i contains curves 

 corresponding with constant values of this variable, the 

 independent variables being the difference in the refrac- 

 tive indices of the two glasses and the logarithmic 

 difference of their powers. The second chart consists 

 of points defining the available types of glass, the 

 scale in one direction varying with the type of 

 chromatic correction desired. The glasses are selected 

 by superposing one chart on the other and finding two 

 representative points on No. 2 which satisfv the condi- 

 tion that one point lies on the curve of No. i corre- 

 sponding with the required type of spherical correction 

 when the other point is on the origin of chart No. 1. 



Paris. 

 Academy of Sciences, June 3. — M. P. Painlevd in the 

 chair. — G. Humbert : The number of classes of in- 

 definite forms of Hermite.— G. Bigourdan : The ob- 

 servatory of the Louis-le-Grand College (last period) 

 and the astronomical work of the French expedition 

 to Pekin. Historical account of work done during the 

 period 1753 to 1782.— M. Hamy : The diffraction of 

 the solar images.— Y. Delage : Lymphatic bleeding as 

 a means of deintoxication. In cases where there is a 

 limited amount of a toxin in the system, and where 

 bleeding followed bv transfusion is too dangerous, the 

 possibility of a lymphatic bleeding is suggested,^ with 

 a subsequetit introduction of a sufficient quantity of 

 artificial blood serum. The operation would ad- 

 mittedly be difficult, on account of the smallness of 

 the lymphatic vessels and the nature of their walls. — 

 — Ch. Dep^ret : An attempt at the general chrono- 

 logical co-ordination of Quaternary' times. — G. A. 

 j Bonlenger : The Helodermatid lizards of the Upper 

 i Eocene in France. — G. Giraud : A partial differential 

 equation, not linear, of the second order, connected 

 with the theory of hyperfuchsian functions. — A. Buhl : 

 The volumes swept out by the rotation of a spherical 

 contour. — E. Belot : The great velocities in novae and 

 the vortex theory of cosmogonv. — A. Vironnet : The 

 contraction of stars and eouilibrium of nebulae. — 

 I E. Liger : o-Oxycinchonine. The compound previously 

 described as oxvcinchonine is shown to be o-oxy- 

 dihvdrocinchonine, and is formed by the addition of a 

 i molecule of water to cinchonine. — T- Peyriguey : A 

 i waterspout in the Gharb.— D. Berthelot and R. 

 ! Trannoy : The evolution of the saccharine principles 

 i of the sorghum and the influence of castration. In 

 normal times sorghum cannot compete with beetroot 

 or sugar-cane as a source of sugar. Owing to the 

 I presence of levulose. glucose, and gums, the sorghum 

 j juices crystallise badly. Moreover, after the plant is 

 ! cut the saccharose reverts, and this phenomenon is 

 i even shown bv the j?rowing plant after a certain date. 

 .As the plant is easilv grown, the juices expressed in 

 a domestic fruit-press may be uced in svrup form widi 

 advantage under present conditions. — L. LIndct : The 

 influence that the vegetable function of yeast exerts 

 on the yield of alcohol ; a new interpretation of the 

 fermenting power— T. Nageotte : Thd value of the 

 ultramicroscope in histological investigation. The 

 ultramicroscope can rp^d^r gre»t,servj[Gef? to histology. 



