July 7, 1904] 



NATURE 



239 



quantity of carbon. — Some alkyl derivatives of sulphur, 

 selenium and tellurium : A. Scott. A description of the 

 derivatives obtained by the action of various alkyl iodides 

 on these elements. — The ultra-violet absorption spectra of 

 certain eHo/-fce(o-tautomerides, part i., acetylacetone and 

 ethyl acetoacetate : E. C. C. Baly and C. H. Desch. 

 From comparative observations of the absorption spectra 

 of these compounds under various conditions, the conclusion 

 is drawn that with acetylacetone, ethyl acetoacetate, and 

 their metallic derivatives, a state of dynamic isomerism 

 exists in the solutions, and that this isomerism is evidenced 

 by a characteristic band in the spectra. — The action of acetyl 

 chloride on the sodium salt of diacetylacetone and the 

 constitution of pyrone compounds ; J. N. Collie. A de- 

 scription of three isomerides obtained in this reaction, from 

 the study of which the author has been led to assign a new 

 constitution to pyrone and its derivatives. — Our present 

 knowledge of the chemistry of indigo : W. P. Bloxam. 

 .Some observations on the purity of commercial indigotin 

 and on the composition of indirubin were made. — A'-'- 

 Dihydrobenzene : .•\. W. Crossley. A description of the 

 formation and properties of this substance is given. — The 

 absorption spectrum of /)-nitrosodimethylaniline : W. N. 

 Hartley. The absorption caused by p-nitrosodimethyl- 

 aniline at the less refrangible end extends into the infra- 

 red, and at the more refrangible far into the ultra-violet. 

 The transmitted rays are thus restricted to a band of yellow 

 and green light bordered on either side by a band of intense 

 absorption. The alkyl-substituted phenols and anilines 

 absorb varying quantities of the ultra-violet, the absorption 

 not extending into the visible spectrum ; but it is also 

 shown that the introduction of the NO, as distinguished 

 from the NOH group, extends the absorption far into the 

 coloured rays. — The influence of solvents on the rotation of 

 optically active compounds, part vi., the relationship 

 between solution-volume and rotation of the dialkyl and 

 potassum ' alkyl tartrates in aqueous solution ; T. S. 

 Patterson. — The constitution of hydrastinine : J. J. 

 Dobbie and C. K. Tinkler. Solutions of hydrastinine in 

 ether or chloroform are colourless, and their absorption 

 spectra are practically identical with the spectra of hydro- 

 hydrastinine. From this it is argued that the carbinol 

 formula should be preferred to the open-chain or aldehydic 

 formula of Roser. On the other hand, the aqueous or 

 alcoholic solutions of hydrastinine give spectra which agree 

 with those of the hydrastinine salts, whence it w'ould appear 

 that, under the influence of these solvents,, hydrastinine 

 changes from the carbinol to the ammonium base. — The 

 influence of moist alcohol and ethyl chloride on the boiling 

 point of chloroform : J. Wade and H. Finnemore. 

 Chloroform made from alcohol contains, in addition to 

 alcohol, a small quantitv of ethyl chloride, both of which 

 depress the boiling point. — Limonene nitrosocyanides : 

 \V. A. Tilden and F. P. Leach. The nitrosocyanide de- 

 scribed by Tilden and Burrow-s as a liquid is found to be 

 a crystalline optically active solid having m.p. 90-91°, and 

 [a]n-(-i65°. — Photochemically active chlorine, ii., a pre- 

 liminary notice : C. H. Burgess and D. L. Chapman. 

 — .Additive compounds of anhydrous magnesium bromide 

 with organic oxygen and nitrogen compounds : J. J. 

 Sudborough, H. Hibbert, and S. H. Beard. — Differenti- 

 ation of primary, secondary, and tertiary amines. .A pre- 

 liminary note ; J. J. Sudborougrh and H. Hibbert. — 

 Influence of radium radiations on labile stereoisomerides : 

 J. J. Sudfaoroush. The results indicate that aWo- 

 cinnamic acid and its a and 3 bromo-derivatives are trans- 

 formed more readilv under the influence of sunlight than 

 bv prolonged exposure to radium radiations. — Notes on 

 analytical chemistry : G. T. Morgran. The separation of 

 arsenic by distillation in hydrogen chloride. The estim- 

 ation of carbon bv oxidation with chromic acid. — Nitrogen 

 chlorides containing two halogen atoms attached to the 

 nitrogen : V. D. Chattaway. — Sulphonphenylchloroamides 

 and sulphontolylchloroamides : F. D. Chattaway. 

 — Stereoisomeric glucoses and the hydrolysis of 

 glucosidic acetates : E. F. Armstrong: and P. S. 

 Arup. It was shown that the acetyl groups are 

 removed with unequal readiness from the penta-acetates of 

 glucose and galactose and from sucrose octaacetate, and 

 with equal readiness from the tetra-acetates of the methyl- 

 glucosides and galactosides. — The colouring matter of the 



NO. t8io, vol. 70] 



flowers of BuXea frondosa : A. G. Perkin. This dye-stuff 

 is shown to contain two substances, butin and butein, which 

 are closely related in constitution, the former being a 

 chalkone compound and the latter the corresponding 

 flavonone isomeride. — Cyanomaclurin : A. G. Perkin, 

 This product, which exists in jackwood, closely resembles 

 the catechins in constitution, and is probably derived from 

 them by the replacement of a catechol nucleus by resorcinol. 

 — The determination of acetyl groups : A. G. Perkin. A 

 description of a hydrolytic method of estimating acetyl 

 groups in organic compounds. — Note on the catechins : 

 A. G. Perkin. A description of the acetyl derivative of 

 the catechin (acacatcchin) derived from Acacia catechu is 

 given. — \ constituent of Java indigo ; A. G. Perkin. It 

 is shown that the yellow colouring matter present in Java 

 indigo is identical with kampherol. 



Royal Microscopical Society, June 15.— Dr. D. H. Scott, 

 F.R.S., president, in the chair. — .\ direct proof of .Abbe's 

 theorems on the microscopic resolution of gratings : Prof. 

 J. D. Everett. The image of the grating formed by the 

 objective is the resultant effect of the disturbances in the 

 image plane due to the diffraction spectra formed in the 

 focal plane. The optical path measured from a plane wave- 

 front, before incidence on the grating, to the spectrum of 

 order o, is unaffected by displacement of the grating. The 

 path to a spectrum of order i is altered by Aat/s, and to a 

 spectrum of order n by nXxjs, by a shift x of the grating, 

 s denoting the distance between rulings. At a fixed point 

 P in the image plane, the interference of the spectrum of 

 order o with a spectrum of order n goes through a complete 

 cycle, while x increases by sjn. That is, n lines in the image 

 move across P during a displacement s of the grating. 

 Similar reasoning applies to the interference of any two 

 of the spectra, and gives Abbe's results. A displacement 

 X towards either side diminishes the paths to the spectra 

 on this side, and increases the paths to the spectra on the 

 other side. When only one spectrum operates, there is no 

 interference and no alternation of brightness. — The recent 

 Foraminifera of the Malay Archipelago : F. W. Millett. — 

 Nature's protection of insect life : F. Enock. 



Physical Society, June 24.— Dr. R. T. Glazebrook, F.R.S., 

 president, in the chair. — Chemical dissociation and electrical 

 conductivity : A. E. Garrett and Dr. R. S. Willows. It 

 has been shown by Beattie {Phil. Mag., 1899) that a 

 mixture of salt and iodine, when placed on a zinc plate and 

 heated, gives rise to electrical conductivity, although 

 separately no such effect is produced. This is shown to be 

 due to the formation of zinc iodide. Following on this the 

 electrical conductivity produced by heating various salts is 

 investigated under different conditions of temperature and 

 electric field. .A large excess of positive electricity is found 

 in nearly every case. — The magnetisation of iron in bulk : 

 Dr. \V. M. Thornton. The paper is in three sections. 

 The first describes a method of measuring large quantities 

 of magnetism by the use of an exploring coil placed around 

 the core and an exciting coil in series with a recording 

 milli-voltmeter. The second section deals with the curves 

 of rise of magnetising currents, when the core is solid and 

 when laminated, as affected by the reaction of the core- 

 currents, and also by the change of permeability during 

 magnetisation. In the last section an example is given of 

 the sudden dip in the curve of rise observed only with large 

 cores. 



Paris. 



Academy of Sciences, June 27. — M. Mascart in the chair. — 

 Researches on cyanogen : solubility and polymerisation : 

 M. Berthelot. There is no true coefficient of solubility 

 of cyanogen in water or alcohol, a slow chemical reaction 

 taking place from the first. With other solvents, such as 

 acetic acid, turpentine, chloroform, and benzene, the 

 ordinary laws of solution are obeyed. — Researches on 

 c\anogen and on its reaction with potassium cyanide : M. 

 Berthelot. An attempt to prepare polycyanides correspond- 

 ing to the triiodides was not successful. Cyanogen is 

 rapidly absorbed by a solution of potassium cyanide, but no 

 compound corresponding to potassium triiodide was obtained, 

 the gas being partly hydrolysed and partly polymerised. — 

 On the distribution of time at a distance by means of 

 wireless telegraphy : G. Bigrourdan. The e.xperiments 

 described have been successful up to a distance of 2 kilo- 



