Septemijek 24, 1908J 



NA TURE 



535 



The results are summarised in the following formula : — 



Dielectric loss per^ 

 cubic centimeire • = fSj X 10"'- ^^ MS '■^"*' '''''*'' Jo"l>-' . 

 in lime t J 



where V is the R.M.S. potential gradient per centimetre 

 and / is the number of cycles per second. 



The results are illustrated with curves and tables, &c. 

 A historical risumi is also given. 



June 25. — " On the Atomic Weight of Chlorine." By 

 Dr. Edward C. Edgrar. 



Three years ago Prof. Dixon and I published the results 

 of nine direct determinations of the equivalent of chlorine. 

 Our method was to burn a jet of hydrogen in an atmo- 

 sphere of chlorine ; and the number wc obtained was 

 appreciably higher than that approved by the International 

 Committee on Atomic Weights. We found, however, when 

 water was used to condense the hydrogen chloride formed 

 in the flame, that some of the water vapour was decom- 

 posed by the free chlorine ; so, in continuing the investi- 

 gation, I avoided this by burning a jet of chlorine in dry 

 hydrogen, condensing the hydrogen chloride as it was 

 formed in a tube dipped into liquid air. In some of the 

 experiments the hydrogen chloride formed has been 

 weighed. My experiments (concluded in 1907) agree closely 

 with the results previously obtained in 1905. The method 

 employed was briefly as follows : — 



.\ vacuous quartz combustion vessel was filled with 

 hydrogen from a weighed palladium bulb. Chlorine was 

 ignited by a spark at the tip of a quartz jet, and continued 

 to burn in the atmosphere of hydrogen until nearly all the 

 chlorine weighed had been burnt. The hydrogen chloride 

 as it was formed in the flame condensed in a limb of the 

 combustion vessel dipped into liquid air, and a little 

 chlorine which had escaped burning also solidified. At the 

 end of the combustion the residual gas was extracted by 

 the pump and analysed ; it proved to be practically pure 

 hydrogen. 



Then the hydrogen chloride was allowed to pass through 

 a quartz tube filled with mercury vapour, where the 

 chlorine it contained was completely removed, and the 

 purified gas passed on to a steel bomb immersed in liquid 

 riir. where it was condensed in six experiments and 

 successfullv weighed in three. In two other exneriments 

 the hydrogen chloride was absorbed by water and weighed 

 as aqueous acid. 



In eight complete combustions about iV5 grams of 

 hydrogen were burnt. Taking the atomic weight of 

 hydrogen as 1-00762, the direct ratio 



weight of chlorine burnt 

 weight of hydrogen burnt 



yielded the mean value 35-462-1-00008 for the atomic 

 wf ,ght of chlorine, while the ratio 



weight of hydrogen chloride caught — 



weight of hydrogen burnt 

 weight of hydrogen burnt 



gave 35-461+0-0009 (mean value of five experiments). 



The accepted value for chlorine, '^^-jc. is in process of 

 revision by the International Committee this year. 



" Further Note on a Luminous Glow generated by 

 Electrostatic Induction in an Exhausted Vessel made of 

 ■Silica." By F. J. Jervis-Smith, F.R.S. 



.\ glow-bulb rotating w-ithin a cylindrical inductor, end 

 dome-shaped, placed symmetrically, with respect to the 

 axis of rotation of glow-bulb, exhibited glow and magnetic 

 phenomena described already (Proc. Roy. Soc, January 30; 

 Nature, May 21, p. 71). Sir Oliver Lodge repeated some 

 nf the author's experiments with glass bulbs, and obtained 

 the -ime effects. Bulbs similar in shape and size to those 

 dfs ribed, but of pure silica, were employed. The residual 

 gas in silica glow-bulbs was air. The glow-bulb was sup- 

 ported 0-5 cm. from a disc-shaped terminal of an induc- 

 tion coil. Opposite the bulb a pointed terminal (negative) 

 was placed, a brush discharge played over the bulb. Coil 

 in action, bulb illuminated with brilliant emerald-green 



NO. 2030, VOL. 78] 



glow. Discharge stopped, glow continued, dying out irj 

 about fifteen minutes. This remarkable after-glow could 

 be easily seen at a distance of 4 metres from the bulb. 

 Glass bulbs do not exhibit this phenomenon. 



A silica glow-bulb was mounted in the rotating apparatus 

 already described. The inductor charged from about 1800 

 volts to 2000 volts. The silica glow-bulb gave out a glow 

 unlike that of the glass bulbs. In experiments with glass 

 bulbs the glow was not strong when the inductor was 

 charged to about 1800 volts ; also, magnetic phenomena 

 could only be seen at a distance of 02 5 metre to 0-5 metre 

 from the apparatus ; but when a silica bulb, similar in size 

 and exhaustion to the glass bulbs, was rotated, it could 

 be seen without difficulty in the dark at a distance of 

 5 metres, and when the inductor was charged up to 30oc> 

 volts to 4000 volts it was clearly visible at 15 metres from 

 the glow-bulb. 



The magnetic phenomena are the same as those which 

 exist when a glass glow-bulb is used. 



A silica glow-bulb rotated in contact with dry mercury 

 was negatively electrified, and exhibited a greenish glow. 

 The potential on surface reached 1500 volts, and through 

 an applied collector charged a Leyden jar. A mercury jet 

 playing on a silica glow-bulb caused it to glow, and 

 negative electricity was generated. 



Paris. 

 Academy of Sciences, September 14.— M. Bouchard in 

 the chair. — Determination of the triple orthogonal systems 

 comprising a family of Dupin eyelids, and, more generally, 

 a family of surfaces with lines of curvature plane in the 

 two systems : Gaston Darboux. — Some mixed forms of 

 nuclear alterations : Joannes Chatin. — Observations of the 

 comet 1908c made at the Observatory of Marseilles with 

 the Lichens equatorial of 26 cm. aperture : M. Borrelly, 

 Observations were made on September 3, 4, 6, 7, and 11, 

 the positions of the comparison stars and apparent posi- 

 tions of the comet being determined. The comet is of 

 the tenth magnitude. — Observations of the new comet 

 1908c made at the Observatory of Besancon with the bent 

 equatorial : P. Chofardet. Similar observations for 

 September 5. — The quadric of Lie : A. Demoulin. — Plane 

 flight without motive power : Ernest Esclangon. Re- 

 marks on the recent notes by M. Marcel Deprez on the 

 hovering flight of birds.— The liquid crystals of the ether 

 salts of ergosterol : Paul Gaubert. The ethers of ergo- 

 sterol present a liquid anisotropic phase, but with the 

 propionate and acetate this phase is rather difficult to 

 show, thus differing from the corresponding ethers of 

 cholesterol.— The virulence of bacilli in relation to the 

 course of pulmonary tuberculosis : A. Rodet and P. 

 Delanoe. The virulence of the bacilli from a large 

 number of tuberculous patients was tested by inoculation 

 into rabbits and guinea-pigs. The experiments on the two. 

 animals do not lead to exactly parallel results; the two- 

 scales of virulence agree nearly absolutely at the extremes, 

 but in the interinediate stages the concordance is not scr 

 good. There is a distinct relation between the virulence 

 as shown by these experiments on animals and the course 

 of the disea'se in the patients from whom the bacilli were 

 derived. Predisposition of the tuberculous patient is not 

 the only factor in determining the course of the disease r 

 the virulence of the bacillus is also a determining factor. 



The intra-dermo-reaction with tuberculin in animals : G. 



Mouasu and Ch. Mantoux. The intra-dermo-reaction, if 

 practised in the manner described, is absolutely without 

 anv effects on healthv animals ; in the case of tuberculous 

 .Tnimals there is no general thermal reaction and no mter- 

 ference with the genera! health, and the method appears 

 to be very certain in its indications. — Some physiological 

 properties of the muscles of invertebrates : Jan Sosnow«ki. 



Calcutta. 



Asiatic Society of Bengal, September 2.— A polyglot list 

 of birds in Manchu, Chinese, and Turki, part ii. : Dr. 

 E. D. Ross. In 1877-8 Robert Shaw published in the 

 journal of this society a grammar and vocabulary of the 

 Turki language. At the end of the vocabulary was printed' 

 a list containing upwards of 150 Turki names of birds with 

 their identifications, prepared by Dr. Scully, who accom- 



