226 



NATURE 



[December 15, 1910 



and of the inner radius of the outer tube. It depends on 

 the radius of the inner wire. Steinmetz's experimental 

 results on the sparking distances between parallel rods are 

 in substantial agreement with Whitehead's figures. An 

 empirical formula based on experimental results published 

 by Kowalski and Rappel is given for the sparking voltages 

 between equal spherical electrodes. The electric stress at 

 the moment of discharge has a minimum value when the 

 distance between the electrodes is a certain function of 

 their radius. Great stress is laid on the currents of 

 electrified air which stream round the electrodes before the 

 discharge takes place. These currents often modify the 

 values obtained for the disruptive stress at the moment of 

 discharge. The similarity between the formulae for the 

 temperature gradient at the surface of a hot wire cooling 

 in air and the empirical formula for the potential gradient 

 at the surface of an electrified wire when ionisation is 

 taking place at its surface is pointed out. — Prof. R. J. 

 Strutt.: The afterglow of electric discharge. When the 

 electric discharge has passed at low pressure through 

 certain gaseous mixtures, a luminosity survives for some 

 seconds after the dischai-ge has been turned off. An 

 improved method of experimenting on the phenomena was 

 introduced by Dewar. A powerful air-pump is used to 

 draw a regulated current of gas through the vacuum tube. 

 A continuous removal of the gas from the region of dis- 

 charge is effected, and the afterglow which it emits, in 

 passing through another vessel on its way to the pump, 

 can be examined continuously and at leisure. There has 

 been difference of opinion as to whether pure oxygen shows 

 a glow or not. The glow, if any, is certainly exceedingly 

 faint. With air a bright yellow glow is obtained, which 

 is improved by enriching the air with oxygen. Pure 

 nitrogen gives no glow whatever. Previous experimenters 

 have connected the glow with ozone, though without ex- 

 pressing definite views as to what part ozone played. The 

 evidence for this has been that the glow is only obtained 

 where oxygen is present, and that it is destroyed by heat. 

 Additional evidence has been obtained, (i) The glow can- 

 not survive passage through a tube cooled in liquid air. 

 This is regarded as due to condensation of ozone. (2) It 

 is destroyed by passage over oxides of copper, manganese, 

 and silver. Ozone is known to be destroyed by these 

 substances. (3) While the glowing gas oxidises bright 

 silver, the gas current beyond the point at which the glow 

 has died out does not do so. Disappearance of the glow 

 is simultaneous with disappearance of ozone from the gas. 

 The glow involves consumption of ozone. It is natural 

 to regard it as a flame of low temperature, arising from 

 the oxidation of some other body by ozone. Experiments 

 were made to determine the nature of this other body. 

 A current of ozone from a vacuum tube fed with oxygen 

 was allowed to mix with any other gas which it was 

 desired to test on its way to the pump. Nitrogen or 

 ordinary air added to the ozone gave no effect, but air 

 which had been through an independent discharge, and 

 had been deprived of its original glow by silver oxide, was 

 found to glow a'gain on mixing with ozone. Some body 

 is produced in air by the discharge the oxidation of which 

 is responsible for the glow. This body is nitric oxide. 

 On leading a current of this gas into the ozone stream a 

 brilliant glow was obtained of the characteristic \'ellow 

 colour. This glow can be produced in the form of a 

 pointed flame, with dark inner cone. The glow is not 

 associated with a sensible rise of temperature. Condensing 

 the ozone with liquid air, allowing it to re-evaporate, and 

 admitting nitric oxide to it, a yellow flash can be obtained 

 long after the electric discharge is over. The glow is 

 purely chemical in its origin. Ozone from the Siemens 

 tube used at atmospheric pressure seems incapable of 

 yielding the glow when mixed with nitric oxide. This 

 may be due to the low percentage of ozone present. The 

 main conclusion is that the ordinary yellow afterglow is 

 due to oxidation of nitric oxide by ozone. — L. F. 

 Richardson : The approximate solution of various 

 boundary problems by surface integration combined with 

 freehand graphs. 



Zooloefical Society, November 29. — Dr. H. Woodward 

 F.R.S., vice-president, in the chair. — Dr. H. B. Fantham 

 and Dr. H. Hammond Smith : A possible cause of 

 pneumo-enteritis in the red grouse (Lagopus scoticus). 



NO. 2146, VOL. 85] 



The authors recorded that in grouse-chicks dying of 

 coccidiosis, many of which showed symptoms of pneu- 

 monia, they found coccidian oocysts in the bronchioles, 

 bronchi, and trachea. The coccidian cysts in the bron-] 

 chioles were probably capable of setting up sufficient 

 irritation to account for the pneumonic symptoms. Thes 

 observations were interesting as showing that the mucHl 

 criticised views of Klein, Tegetmeier, and others on 

 " pneumo-enteritic " as a cause of mortality in grouse 

 may have some foundation in fact. — Dr. J. F. Genrimiil : 

 The development of Solaster endeca, Forbes. The author 

 described the ovaries and ova and the processes of spawn- 

 ing, fertilisation, segmentation, and gastrulation, and then 

 dealt with the characters of the free-swimming larvse and 

 the changes related to the metamorphosis. He discussed 

 the development of the internal cavities and of the skele- 

 ton, and described the methods he had employed in obtain- 

 ing and rearing the larvae. The memoir, in addition to 

 details of adult anatomy, contained a description of various 

 points in development. — F. E. Beddard : The alimentary 

 tract of certain birds, and on the mesenteric relations of 

 the intestinal loops. Notes the author had accumulated 

 relative to the viscera of birds which had died in the 

 society's gardens. The paper dealt more particularly with 

 species that had not been carefully studied from the point 

 of view of the convolutions of the intestine, and attention 

 was directed to a considerable series of birds. — Prof. 

 A. Cabrera : The specimens of spotted hyaenas in the 

 British Museum (Natural History). Three apparently 

 new forms were described. 



Linnean Society, December i. — Dr. D. H. Scott, F.R.S., 

 president, in the chair. — Captain C. F. Meek : The 

 spermatogenesis of Stenobothrus viridulus, with special 

 reference to the heterotropic chromosome as a sex 

 determinant in grasshoppers. 



Mathematical Society, December 8. — Dr. H. F. Baker, 

 president, in the chair. — G. H. Hardy : Properties of 

 logarithmico-exponential functions. — G. H. Hardy : Some 

 results concerning the increase of functions defined by an 

 algebraic differential equation of the first order. — A. A. 

 Robb : Optical geometry of motion. — T. C. Lewis : 

 Note on the Pellian equation. — G. B. Mathewrs : The 

 arithmetical theory of binary cubic forms. — Dr. W. H. 

 Young: : The integration of Fourier's series. — Dr. W. H. 

 Young: : The theory of the application of expansions to 

 definite integrals. 



Royal Astronomical Society, December 9. — Sir David 

 Gill, K.C.B., president, in the chair. — A. C. D. Crom- 

 melin : Note on Mr. Innes's paper on the mean or peri- 

 helion distances of comets. — A. Stanley Williams : The 

 equatorial current of Jupiter in 1880. The author con- 

 cluded from observations of eight spots that the rotation 

 period of the equatorial current in 1880-1 was nearly 20 sec. 

 shorter than during the years 1888-1908, amounting to a 

 difference in velocity of about 15 miles an hour. — A. A. 

 Rambaut : Observations of Halley's comet, Daniel's 

 comet (igoge), and comet 1910c, made at the Radcliffe 

 Observatory, Oxford. — A. A. Rambaut : Observations of 

 stars occulted by the moon during the eclipse of 19 10 

 November 16. A photograph of the eclipsed moon and 

 trails of stars was shown, the telescope having been 

 adjusted to the moon's motion during the eclipse. — 

 C. V. L. Charlier : Multiple solutions in the determina- 

 tion of orbits from three observations. The author showed 

 that in certain regions more than one solution could be 

 obtained from the observations, while in others only one 

 was possible ; in consequence of this, much difficulty was 

 somtimes found in obtaining the true orbit, as was the 

 case with comet igioa.^H. H. Turner : The accuracy of 

 the positions of the star images in the " Harvard Sky." 



I By the latter term was intended the Harvard series of 

 fifty-five plates, forming a photographic map of the 



I heavens on a scale about one-eleventh that of the Astro- 



I graphic Catalogue. Formulae were given for computing 

 the optical distortion, varying as the cube of the distance 

 from the centre of the plates, and also for the differential 

 refraction.— S. A. Saunder : The determination of seleno- 



j graphic positions, and the measurement of lunar photo- 



