2g8 



NATURE 



[June 12, 1919 



parabola seen in this type of discharge is that it is 

 due to atomic rays colliding with and capturing 

 slowly moving neutral atoms in the canal-ray tube, 

 and so forming molecular rays of half-normal energy. 

 The second or "molecular" type, wliich has only been 

 obtained associated with the atomic, is characterised 

 by a very bright patch on the molecular parabola 

 corresponding with normal energy, and two fainter equal 

 symmetrical positive and negative satellite patches on 

 the atomic parabola apparently caused by some of 

 the charged molecular rays being dissociated by col- 

 lision with a neutralising electron into atoms of oppo- 

 site charge each with half the normal energy. — 

 C. T. R. Wilson : A micro- voltameter. Experiments 

 were described with a mercury voltameter in which 

 one electrode consists of a sphere of mercury de- 

 posited on the end of a fine platinum wire and 

 measured by means of a microscope. Quantities of 

 electricity varying from a few hundred electrostatic 

 units to about one coulomb may be measured by it. 

 The almost instantaneous change of size of the drop 

 when a capacity of one-tenth of a microfarad, charged 

 to one voli:, is discharged through the instrument is 

 easily observed. A magnet inserted in or removed 

 from a coil connected to the terminals of the volta- 

 meter produces an easily measured effect. Experi- 

 ments were also mentioned which suggest the possi- 

 bility of its application in measurements of much 

 smaller electrical quantities. — R. Whiddington : The self- 

 oscillations of a thermionic valve. It has been found 

 possible to produce oscillations of almost any frequency 

 from a three-electrode vacuum valve without employ- 

 ing the usual capacity induction circuits. Thus a 

 valve with two suitable batteries, one' in the anode 

 circuit, the other in the grid circuit, will produce quite 

 powerful oscillations, the frequency of which will 

 be determined by the value of the grid potential. The 

 phenomenon can be explained by supposing that the 

 oscillations are due to surges of mercury ions closing 

 in on the filament from the grid with a frequency 

 given by the approximate formula 



«2 = --^^., . V, 



fjia - 

 where e/m is the usual charge to mass ratio, d is the 

 radial distance filament to grid, and V is the positive- 

 grid voltage. Experiments conducted so far indicate 

 that the monatomic Hg ion with one live charge is 

 mainly responsible. 



Dublin. 

 Royal Dublin Society, May 27.— Prof. Carpenter in 

 the chair.— Prof. W. E. Adeney and H. G. Becker : 

 The determination of the rate of solution of atmo- 

 spheric nitrogen and oxygen by water. Part ii. This 

 paper gives- further results obtained, using the method 

 of experimenting described previously (Scientific Pro- 

 ceedings R.D.S., vol. XV., p. 385, iqi8), i.e. passing 

 a large cylindrical bubble of air up through a narrow 

 column of de-aerated water repeatedlv until saturation 

 is reached, and measuring the loss in pressure after 

 each ascent. An improved form of apparatus is 

 described and used to determine the rates of solution 

 of oxygen and nitrogen as pure gases between 2-5° C. 

 and 35° C, and determinations of solubility within 

 these limits are also given. It is shown that the 

 rate of solution varies in accordance with the 

 equation 



^-SA/-/^.., 



the values of / being given for the above limits of 

 temperature between which S is nearly constant. The 

 final results are given in the form 



W = (lOO-Wi) i-^"-^Vj» 

 NO. 2589, VOL. 103] 



which gives the amount of gas dissolved (in per- 

 centages of saturation) after any time t, the initial 

 gas-content being equal to Wi. 



Edinburgh. 

 Royal Society, May 5.— Dr. John Home, president, 

 in the chair. — Prof. C. R. Marshall : (i) Some conditions 

 influencing the reaction-velocity of sodium nitrate on 

 blood. Serum and alkalis have a marked retarding, 

 and acids an accelerating^ influence on the action of 

 sodium nitrite on blood. The investigation was made 

 with a spectro-photometer, the part of the spectrum 

 observed being A 571-577. The rapidity of the reaction 

 was affected by the concentration of the blood and of 

 the sodium nitrite. In the case of serum, ferment 

 action played no part. It was found that with minimal 

 concentrations of sodium nitrite an induction period, 

 frequently varying with the specimen of blood used, 

 occurred, which was increased by the addition of 

 serum or sodium hydroxide. The duration of the re- 

 active period was less influenced. The amount of 

 sodium hydroxide necessary to delay the reaction 

 varied with the concentration of sodium nitrite. The 

 reaction occurred in, although it was greatly delayed 

 by, moderately strong alkaline solutions, which seems 

 to show that the action is not due to the formation of 

 nitrous acid. The mode of action of sodium nitrite is 

 promised in a future communication. (2) The mode 

 of action of metal sols. This was an attempt to 

 determine the wav in which metal sols acted thera- 

 peutically by investigating the action of an eleotrolyte- 

 free silver colloidal solution on bacteria. The action 

 could not be explained by Brownian movement, sur- 

 face phenomena, electric charge, catalytic power, or 

 the concentration of ions in the dispersal medium.^ It 

 appeared to be associated with the amicrons which, 

 it is suggested, are taken up by the bacilli and prob- 

 ablv converted into a soluble product.^ — Prof. W. H. 

 Metrler : Factors of circulants. — Capt. T. Bedford 

 Franklin : The cooling of the soil at night. This is 

 a preliminary account of the observations made during 

 the past winter in an endeavour to forecast the oc- 

 currence and severity of frosts. A relation was first 

 established between the rate of radiation of the soil 

 at night and the relative humidity of the air. The 

 observations then showed rthe connection between the 

 loss of heat in the surface of the soil by radiation and 

 the gain of heat in the surface by conduction from 

 the lower and wanner underground layers, together 

 with the latent heat liberated when the surface freezes. 

 It is hoped that in the near future it may be possible, 

 earlv in the afternoon, to forecast the probability and 

 severitv of a frost on the coming night by means of 

 readings of the relative humiditv and of the under- 

 ground temperatures and conductivity of the soil with 

 a set of electrical resistance thermometers. — J. 

 Marshall : An analysis of an electron-transference 

 hvnothesis of chemical valencv and combination. In 

 this paper an analysis is made of the electron-trans- 

 ference hvpothesis of chemical combination put for- 

 ward bv Kelvin in 1902 and bv Sir J. J. Thomson in 

 iqoj.. The methods employed and the assumptions 

 made are similar to those formulated bv H. A. Lorenitz 

 in his discussion of the molecular refractive index of 

 mixtures and compounds (vide "Theory of Electrons"). 

 Part i. of the paper contains a discussion of the value 

 of the atomic refractive index in the case of atoms 

 from which electrons have been transferred, ignoring 

 the contribution to this value arising from fields of 

 electrical force due to the vicinity of other atoms or 

 groups of atoms. In part ii. the author endeavours to 

 obtain a formula for the molecular refractive index 

 which will allow for ithe contribution due to the elec- 

 trical action between the atoms of the molecule. It 



