February 25, 1909 J 



NATURE 



509 



Cambridge. 



Philosophical Society, January 25. —Sir J. J. Thomson, 

 vice-president, in the chair. — A string electrometer : 

 T. H. Laby. An electrometer consisting of a stretched 

 silvered quartz-fibre between two charged plates was shown. 

 Tested on steady potentials it had the following proper- 

 ties : — (i) The sensitiveness for a constant fibre tension in- 

 creased rapidly with increasing potential difference between 

 the plates. {2) With the plates at 67 mm. apart and 

 charged to -hio volts and -10 volts the sensitiveness was 

 more than 70 eye-piece divisions per volt. (3) The deflection 

 of the fibre is proportional to its potential. (4) When not 

 very sensitive it may be used as an oscillograph. Further 

 work is being done on this application of it. — The secondary 

 Rontgen radiation from air and ethyl bromide : J. A. 

 Crowther. The amounts of secondary Rontgen radiation 

 from air and ethyl bromide have been compared, using 

 ethyl bromide as the absorbing gas. The results in the 

 main confirm those previously obtained with air as the 

 absorbing medium. Corrected results for the relative 

 amounts of secondary radiation from these gases are 

 given. — Interference fringes with feeble light : G. I. 

 Taylor. Interference photographs were taken with light 

 of such small intensity that single exposures extended over 

 several months. The fact that they were well defined was 

 taken to indicate an upper limit to the magnitude of the 

 indivisiBIe unit of energy occurring in the non-homogeneous 

 wave-front theory of light. — The solution of linear dif- 

 ferential equations by means of definite integrals : H. 

 Bateman. 



February S. — Mr. S. Ruhemann, vice-president, in 

 the chair. — Further studies on dihydroxymaleic acid : 

 Dr. Fenton and W. A. R. Wilks. The authors 

 are continuing the investigation of the properties 

 and transformations of dihydroxymaleic and dihydroxy- 

 tartaric acids, and in the present communication a brief 

 account is given of some recent results. — Homologues of 

 furfural : Dr. Fenton and F. Robinson. New syntheses 

 have been effected by the application of the Friedel and 

 Crafts reaction to the halogen derivatives of methylfurfural 

 with various hydrocarbons, and the results promise a wide 

 field for further investigation. — -Action of urethane on esters 

 of organic acids and mustard oils : S. Ruhemann and 

 J. G. Priestley. The sodium-derivative of ethyl carbamate 

 reacts with ethyl phenylpropiolate, not by addition, but with 

 formation of ethyl phenylpropiolylcarbamate. Similarly, 

 the esters of fatty saturated acids furnish acid derivatives 

 of ethyl carbamate. Phenyl mustard oil reacts with ethyl 

 sodiocarbamate, and yields the anhydride of diphenylthio- 

 biuretcarbo.xylic acid. Besides this compound, a small 

 quantity of carboxyethylphenylthiocarbamide is formed. 

 Analogous is the action of ethyl sodiocarbamate on other 

 mustard oils. — The absorption spectra of solid tetramethyl 

 picene and of its solutions : .Annie Homer and J. E. 

 Purvis. The absorption bands of a very thin film of the 

 hydrocarbon were compared with those when the substance 

 was in solution in benzene and in alcohol. The results 

 showed that the throe bands were identical in each case, 

 but that there was a shift of both the bands and the 

 general absorption towards the red end of the spectrum, 

 according to the density of the medium. The bands of the 

 solid were shifted towards the red end of the spectrum 

 more than those of the benzene solution, and those of the 

 benzene solution more than in the alcoholic solution. The 

 vapour of the substance was also examined, and it showed 

 a beautiful blue fluorescence, but it decomposed so rapidly 

 that no observations could be made as to its fluorescent 

 spectrum. — The absorption spectra of mesitylene and tri- 

 chloromesitylene : J. E. Purvis. The absorption spectra of 

 N/iooo alcoholic solutions were compared, and the absorp- 

 tion curves were drawn from the numbers obtained. It 

 was found that there was a shift of the bands of the tri- 

 chloromesitylene towards the red end of the spectrum when 

 compared with those of mesitylene. The strong band of 

 mesitylene, A. 275-\ 245, was shifted in the trlchloro- 

 mesitylene to A 287-^ 263, and, besides that, the persistence 

 of the absorption curve of the latter was considerably 

 increased. — The absorption spectra of concentrated and 

 diluted solutions of chlorophyll : J. E. Purvis. The ratio 

 of the dilutions was 1/719, and the diluted solution was 



NO. 2052, VOL. 79] 



placed in a tube 719 times larger than that containing the 

 strong solution. The light, therefore, passed through the 

 same amount of chlorophyll. The two solutions showed 

 exactly the same phenomena at the commencement of the 

 observations. The bands at K 538 and X 565 were equally 

 well marked, and the general absorption was the same. 

 After standing some hours, the diluted solutions showed 

 changes in the appearance of the bands ; X 538 became 

 more diffuse, and \ 538 and \ 565 appeared to diffuse into 

 each other, whilst a band at \ 508 appeared, and the 

 general absorption was almost the same as at the com- 

 mencement. The change continued very slowly for several 

 days. The final result showed that in the strong solution 

 the band \ 538 was as well marked as at the beginning, 

 and that the band X 508, which appeared after some hours, 

 remained the same, and the band \ 565 appeared to be 

 the same as at the beginning. On the other hand, the 

 general absorption had lessened very considerably as com- 

 pared with the dilute solution. These changes are ascribed 

 to the action of enzymes, probably oxydases. — A coloured 

 thio-oxalate : H. O. Jones and H. S. Tasker. Diphenyl- 

 dithio-oxalate is readily prepared by the action of oxalyl 

 chloride on thiophenol, and crystallises in beautiful bright 

 vellow prisms melting at ii9°-i20°. The compound is the 

 first dithio-oxalate known, and it is interesting in that it 

 is coloured, while oxalates are colourless. It appears to 

 distil unchanged, decomposes into thiophenol and potassium 

 oxalate when boiled with caustic potash, and gives off 

 carbon monoxide when treated with sodium or sulphuric 

 acid. — Note on some double fluorides of sodium : W. A. R. 

 Wilks. Cryolite, a double fluoride of sodium and 

 aluminium, has already been prepared synthetically. The 

 author shows that by' carrying out the precipitation in a 

 different way another double fluoride is obtained, which 

 is so insoluble that it may be used as a tost for sodium. 

 Paris. 

 Academy of Sciences. hcL.ruaiy 15.— M. Emile Picard in 

 the chair.— The construction of orthogonal systems which 

 comprise a family of Dupin eyelids : Gaston Darboux.— 

 The tectonic of the PaUeozoic strata at the north-west and 

 north of Sabl^ (Sarthe) : D. P. CEhlert.— M. Jungfleisch 

 was elected a member in the section of chemistry in the 

 place of the late A. Ditte.— Observations of the comet 

 igo8(; (Morehouse), made at the Observatory of .\thens 

 with the Gautier 40-cm. equatorial : D. Eginitis. Four 

 sets of observations, made on November 28, December i, 

 3, and 4, 1908, are given for this comet, together with the 

 apparent positions of the comet and mean positions of the 

 comparison stars. — Selective effect in the ionisation of a 

 gas by an alternating field : Henry A. Perkins.— The 

 melting point of platinum : C. Fery and C. Cheneveau. 

 The F4ry absorption pyrometer used in these experiments, 

 the indications of which, based on Wien's law, are only 

 accurate for a black body, was calibrated against a 

 Le Chatelier couple. The platinum was fused in two ways, 

 by passing an electric current through a wire placed in a 

 horizontal and a vertical position, and by heating in_ a 

 suitable gas burner. The melting points obtained varied 

 from 1690° C. to 1750° C. The variations in the melting 

 point appear to be related to the nature of the gas in 

 which the fusion is produced. — The reversal of the green 

 radiation produced by the mercury arc in a vacuum ; A. 

 Perot.— The influence of the extreme regions of the spec- 

 trum in phenomena of solarisation : A. Gargam de 

 Moncetz.— The compressibility of gases between o and 

 3 atmospheres and at all temperatures : A. Leduc. -A 

 re-calculation for twenty gases of the constants required 

 for determining their molecular volumes at 0° C. and 

 100° C. — The thermal phenomena accompanying the action 

 of water on aluminium powder : E. Kohn-Abrest and J. 

 Carvallo. Water acts on aluminium with evolution of 

 heat (about 1700 calories per gram) at a temperature of 

 about 83° C— The magnetic properties of some easily 

 liquefiabie gases : P. Pascal. The values of the specific 

 magnetic susceptibility are given for eight gases in the 

 liquid state, and, on the assumption that the specific 

 susceptibility is independent of its physical state, the values 

 for this constant for the same gases at 0° and 760 mm. 

 pressure are calculated. — The catalytic oxidation of hypo- 

 phosphorous acid by copper; J. Bougault. Precipitated 



