CHEMICAL NEWS Kinetics of Reaction between Silver Salts and Aliphatic Iodides. Nov. 25, 1910 taken that the warming of the tube, A, does not last so long that the rods and plate are appreciably warmed. Hence the rods must not be connected with the tube at places where the latter is warmed, and, moreover, it is best to use for the apparatus only such materials as are not affected by mercury. Possibly at very low pressures a correction should be made for the pressure of light. This can very easily be determined if the warming is performed electrically, when the emitted energy can be ascertained with sufficient accuracy. SPECIFIC GRAVITIES AT THE MELTING-POINT IN RELATION TO CONSTITUTION. By J. C. EARL. ASSUME that the carbon, hydrogen, and oxygen atoms are spheres of equal size, when in combination, at the meltingpoint of the substance in which they are combined. This is a natural conclusion of the shape of the atoms at the point when the substance containing them changes from a rigid solid structure to a mobile liquid. Consider the case of water at o° C. The molecule H20 at this temperature will consist of three perfect spheres of equal size, just touching one another. There will therefore be interstices between these spheres and also between the spheres constituting this molecule and those conTherefore the actual stituting surrounding molecules. volume taken up by the molecule will be 3x3 plus the volume of the interstices within and surrounding it. In the case of water the number of these interstices is 8 (=2×3+2). Therefore the volume of the water molecule at o° C. = 3x+8x; where x is the volume of one interstice. * can be solved by considering the case of palmitic acid, for example, whose specific gravity at the melting-point is accurately known. The value of r can be taken as unity as it is constant for carbon, hydrogen, and oxygen, whatever compound of these elements is taken. Volume of palmitic acid molecule = 50XY+102x. PROCEEDINGS OF SOCIETIES CHEMICAL SOCIETY. (Concluded from p. 257), 265 235. "The Tautomerism of Glyoxalines and the Con stitution of Pilocarpine." By FRANK LEE PYMAN. (Trans, 1910, 1814). 07 Otto Fischer (Fourn. Prakt. Chem., 1906, [2], lxxiii,, 419; 1907, [2], lxxv., 88) has already shown that benziminazoles are tautomeric, and Jänecke (Ber., 1899, xxxii., 1098) and Gabriel (Ber., 1908, lxi., 1926) have made it seem probable that simple glyoxalines behave similarly, Conclusive evidence that simple glyoxalines react as tautomeric compounds is now brought forward, for it is found that 4 (or 5)-methylglyoxaline yields on methylation a mixture of the two isomerides, I: 4-dimethylglyoxaline (I.) (b. p. 198-1999) and 1:5-dimethylglyoxaline (II.) (b. p. 224-225°) :— Jowett and Potter (Trans., 1903, lxxxiii., 464) by the methylation of 4(or 5)-methylglyoxaline obtained a dimethylglyoxaline which they regarded as a simple substance, but which was not identical with the dimethylglyoxaline obtained by Jowett (Trans., 1903, lxxxiii., 438) from isopilocarpine. It is now shown that the latter compound is identical with 1 : 5-dimethylglyoxaline, and that Jowett and Potter's dimethylglyoxaline was a mixture of the 14- and 1: 5-isomerides, consisting mainly of the former. The methylation of bromo-4(or 5)-methylglyoxaline and dibromo-4(or 5)-methylglyoxaline yields in each case a mixture of two isomeric N-methyl derivatives which have been separated and characterised. The bromination of I: 4- and 1 : 5-dimethylglyoxaline leads to the formation of one of the bromodimethylglyoxalines and one of the dibromodimethylglyoxalines in each case. 236. "Kinetics of the Reaction between Silver Salts and Aliphatic Iodides." By FREDErick George Donnan and HAROLD EDWARD POTTS. (Trans., 1910, 1882). The experiments of Burke and Donnan (Trans., 1904, lxxxv., 555) have shown that the reaction between silver nitrate and an alkyl iodide in alcoholic solution is disturbed by an accelerating effect due to one of the products. In the present paper it is shown that in the reaction between silver lactate and ethyl iodide in aqueous alcohol, the accelerating effect disappears. It is also shown that in the reaction between silver nitrate and ethyl iodide in a nonhydroxylic solvent (acetonitrile) when no free (nitric) acid is produced, the kinetic behaviour does not essentially differ from that observed in alcoholic and aqueous solutions. The reaction between iodoform and silver nitrate in alcoholic solution follows the same pseudo-bimolecular equation as the reaction between a mono-iodide and silver nitrate. It was found that methylene iodide reacts very sluggishly with silver nitrate in alcoholic solution. Owing to the rapid decomposition of carbon tetraiodide in alcoholic solution, comparative experiments with this substance could not be carried out with sufficient accuracy. Although the matter could not be decisively settled, the general trend of the experimental evidence is in favour of the view that it is the undissociated silver salt which reacts with the alkyl iodide in the first instance, with the formation, The sugges possibly, of a transient intermediate product. tion is made that the constancy of the velocity-coefficient in any particular reaction is due to a compensation of the decrease due to the increasing relative ionisation of the silver salt by the acceleration referred to above. Senter's suggestion that the acceleration is due to the silver halide produced is discussed, 237. "The Identity of Osyritrin, Myrticolorin, Viola | salts, but it is greatly retarded by the presence of excess of quercitrin, and Rutin." By ARTHUR GEORGE PERKIN. alkali. (Trans., 1910, 1776). It has been shown (Trans., 1902, lxxxi., 477) that osyritrin, myrticolorin, and violaquercitrin are identical. Schmidt (Arch. Pharm., 1908, ccxlvi., 214) and Wunderlich (Ibid., ccxlvi., 224) have found that when hydrolysed violaquercitrin gives, in addition to quercetin and dextrose, also rhamnose, and that this glucoside is identical with rutin, which yields the same products. It therefore appeared certain that osyritin and myrticolorin in reality consist of rutin, and this has been found to be the case. 238. "A Glucoside from Tephrosia purpurea." By GEORGE CLARKE, jun., and SHRISH CHANDRA Banerjee. (Trans., 1910, 1833). Tephrosia purpurea (Pers.), nat. ord. leguminosa, contains a yellow crystalline_glucoside (Clarke and Banerjee, Proc., 1909, xxv., 16). This substance has been further investigated, and has the formula C27H30O16,3H2O. When hydrolysed, it is decomposed into quercetin, dextrose, and rhamnose according to the equation C27H30016+ 3H2O = C15H1007 + C6H12O6+ C6H12O5, H2O. It is identical with rutin described by Schunk (Trans., 1888, liii., 264), which therefore has the above formula, and not that hitherto ascribed to it. 239. "The Molecular Complexity of Amides in various Solvents. Part III. Amides in Aqueous Solution." By ANDREW NORMAN MELDRUM and WILLIAM ERNEST STEPHEN TURNER. (Trans., 1910, 1805). By these experiments the existence of a new type of optically active substances is demonstrated, the molecular asymmetry of which is determined by the peculiar configuration of the doubly linked tervalent nitrogen atom. In addition, direct proof is afforded that in the oximino-group the three valencies of the nitrogen atom are directed along the three edges of a trihedral angle, as was postulated by Hantzsch and Werner (Ber., 1890, xxiii., 11). 241. "The Resolution of Benzoyloscine." By FRANK TUTIN. (Trans., 1910, 1793). the fractional crystallisation of its d-bromocamphorsulBenzoyloscine (benzoylscopoline) has been resolved by phonate. Benzoyl-d-oscine d-bromocamphorsulphonate forms needles, which melt at 246°, but benzoyl-1-oscine d-bromocamphorsulphonate could not be obtained in a state of purity. Benzoyl-d-oscine hydrochloride melts at 283284°; the corresponding nitrate at 200°; the picrate at 211-2120; and the aurichloride at 189-190°. Benzoyl-d-oscine has [alD +35° in 50 per cent alcohol, whilst the ion of this base has [a] D +100°, calculated from the rotation of its d-bromocamphorsulphonate. d-Oscine was prepared in the form of its hydrochloride by hydrolysing benzoyl-d-oscine with hydrochloric acid. It has a specific rotation of about +77.7°. Benzoyloscine d-camphorsulphonate melts at 167-168°, and forms microscopic diamond-shaped crystals, but it could not be resolved by fractional crystallisation. 242. "Carboxylic Acids of cyclohexanone and some of In continuation of their previous work (Trans., 1908, its Derivatives." By HENRY DENT GARDNER, WILLIAM xciii., 876); 1910, xcvii., 1605) the authors have determined HENRY PERKIN, jun., and HUBERT WATSON. (Trans., the molecular complexity of fourteen additional amides in aqueous solution. Water, by reason of its high dielectric 1910, 1756). A detailed account of an investigation of which a preconstant, should prevent association of the solute, accordingliminary note has already appeared (Proc. Chem. Soc., xxvi., 136). to the Nernst-Thomson rule. The authors find that fifteen out of the total of twenty-three amides examined are associated in water. The authors hold that association in water is of frequent occurrence, and has been ignored in the study of aqueous solutions to an injurious extent. They find that during the hydrolysis of ethyl acetate, or the inversion of sucrose, by hydrochloric acid, the presence of methylacetanilide, an associated substance, has an effect similar to that caused by the presence of sodium chloride, as observed by Caldwell (Proc. Roy. Soc., 1906, A, lxxviii., 272) and H. E. Armstrong (loc. cit., 1907, A, lxxix., 576). The accelerations due to equal weights of the two foreign substances are approximately the same. 240. "Optically Active Salts of 4-Oximinocyclohexane carboxylic Acid and the Configuration of the OximinoGroup." By WILLIAM HOBSON MILLS and ALICE MARY BAIN. (Trans., 1910, 1866). If morphine (1 mol.) is added to the ethyl-alcoholic solution of 4-oximinocyclohexanecarboxylic acid, the morphine salt which separates contains a dextrotatory form of the acid, for on decomposing it with excess of ammonia and removing the morphine, the solution of ammonium salt obtained is strongly dextrorotatory, the molecular rotation varying from [MD 50° to [MD 60° in different preparations. Similarly, from the quinine salt (Proc., 1909, xxv., 178), which has been crystallised from water, the corresponding lævorotatory ammonium salt, [M] D -70° to -80°, has been obtained. That the substances to which these optically active solutions of ammonium salt owe their rotatory power are the normal ammonium salts of dextro- and lævo-rotatory forms of 4-oximinocyclohexanecarboxylic acid was shown by treating the solutions with silver nitrate. The substances thus precipitated were pure silver salts of this acid, and when treated with an aqueous solution of sodium chloride they gave respectively dextro- and lævo-rotatory solutions of the corresponding sodium salts, the molecular rotations observed being [M]D 745° and -79.9°. Autoracemisation takes place very rapidly in neutral solutions of these optically active 243. "Note on the Constitution of a-Elaterin." By CHARLES WATSON MOORE. (Trans., 1910, 1797). The following formulæ have, at various times, been suggested for elaterin :-C20H2805 (Zwenger); C22H3006 (Thoms); C24H34O6 (Hemmelmayr); and C28H 3807 (Berg). The present author has now obtained results which prove the correctness of the empirical formula suggested by Berg. The presence of an acetyl group in elaterin has been confirmed, but it has been shown that this substance contains no ketonic or aldehydic group. Two crystalline substances have been obtained by the oxidation of "elateric acid," which have been shown to possess the formulæ C24H32O4 and C24H3005 respectively. The latter of these is a diketone, and has been designated elaterone. On distillation with zinc dust, elaterin yields 1 : 4-dimethylnaphthalene. The results so far obtained indicate that the formula of elaterin may be represented as follows: 244. "The Viscosity of Salt Solutions." BY MALCOLM PERCIVAL APPLEBY. (Trans., 1910, 2000). By the use of specially standardised viscometers of a modified Ostwald type, the viscosities of aqueous solutions of lithium nitrate have been determined at 25°, 18°, and o° over wide ranges of concentration with an error of not more than o'o1 per cent for solutions less concentrated than normal. The formula of Grüneisen (Wiss. Abh. Phys. Tech. Reichs., 1905, iv., 151) is found not to represent the phenomena of dilute solution. A method of calculating the viscosity of salt solutions from their hydration numbers, or vice versa, has been described. The application of this method to the viscosities of solutions of lithium nitrate at 18° and 25° gives results consistent with the estimates of NEWS ionic hydration made by other observers. The application | a preliminary account of which has already appeared (Proc. of the method to some other salts is discussed. 245. "Some Reactions of Keten. Combination with Hydrocyanic Acid." By STELLA DEAKIN and NORMAN THOMAS MORTIMER WILSMORE. (Trans., 1910, 1968). The compound which was mentioned (Proc., 1908, xxiv., 77) as being formed by the action of keten on hydrocyanic acid has been further investigated. In a pure state it is a colourless liquid, which boils undecomposed at 110.2°(corr.)/100 mm., and with slight decomposition at 173°/772 mm. It may be frozen to a white solid, which melts at · 196° to - 195°. Analysis and determination of molecular weight show that it has the composition C5H5O2N. The new substance is decomposed by water with formation of acetic and hydrocyanic acids, and by alcohol in the presence of mineral acids, ethyl acetate and hydrocyanic acid being obtained. It also reacts with aniline, giving acetanilide and hydrocyanic acid. It is tentatively suggested that the new compound may be a acetoxyacrylonitrile, CH2:C(CN)·O·CO·CH3, a constitution which is shown to be consistent with the molecular volume, refractivity, and dispersion of the substance. The actions of magnesium methyl iodide and of nitrosyl chloride on keten have also been studied. With the former acetone is produced, and with the latter chloroacetyl chloride; but in both cases the greater part of the keten condenses with the formation of brown resins. 246. "The Polymerisation of Keten. cyclo Butan-1 : 3dione Acetylketen")." By FRANCES CHICK and NORMAN THOMAS MORTIMER WILSMORE. (Trans., 1910, 1978). The research on the polymerisation of keten (Trans., 1908, xciii., 946) has been continued, and the first or bimolecular polymeride has been more fully studied. This substance combines with bromine to form a bromoaceto acetyl bromide, which with alcohol gives y-bromoacetoacetic ester and not the a-derivative, showing conclusively that the bimolecular polymeride is cyclobutan-1 : 3-dione and not acetylketen, as previously supposed. From the bromoacetoacetyl bromide an anilide was also obtained, identical with the bromoacetoacetanilide described by Knorr (Annalen, 1886, ccxxxvi., 79), which shows that the bromine in this substance is in the y- and not in the a-position, as believed by him. As a further consequence, the bromohydroxymethylquinoline, obtained by Knorr by the action of sulphuric acid on bromoacetoacetanilide, would seem to have the bromine attached to the methyl group and not to the nucleus, or else the bromine atom must wander from the methyl to the CH2 group during the condensation. With ammonia, cyclobutan - 1 : 3-dione forms, in the first place, the acetoacetamide described by Claisen and Meyer (Ber., 1902, xxxv., 583); but by the further action of ammonia an oil is obtained, which appears to consist chiefly of aminocrotonamide, since on heating it gives a compound having the composition C8H1302N3, which is in all probability a lutidine derivative, namely, 4-amino-2 : 4-dimethyl-▲-tetrahydro-6-pyridone-3carboxylamide. With semicarbazide, cyclobutan-1: 3-dione forms the semicarbazone-semicarbazide of acetoacetic acid. With magnesium methyl iodide, diacetone alcohol appears to be formed in small quantity. With hydrogen in presence of platinum black, cyclobutan-1: 3-dione is reduced to butyraldehyde. It does not react with sodium, with phenylcarbimide, or with hydrocyanic acid. On long keeping, or on warming, it polymerises with formation of dehydracetic acid. Much work has been done with a view to elucidating the nature of the yellow crystalline compound, which is formed from cyclobutan-1 : 3-dione in the presence of quinoline; but so far no clue to its constitution has been found. Its empirical formula is, however, C13H10O3. It is possibly a naphthalene derivative. Chem. Soc., xxvi., 142). The behaviour of triphenylstibine towards various oxidising agents, such as concentrated sulphuric acid, and potassium permanganate, is described, and the relation between various derivatives of triphenylstibine oxide, and the influence of the nitro-group in the molecule are also discussed. 248. "Contributions to our Knowledge of the Sulphide Dye-stuffs." Part I. By GEORGE HERBERT FRANK. It has been found that many colouring matters belonging to the "sulphide" class readily combine with chloroacetic acid, giving carboxylic derivatives which are readily soluble in alkalis. The colouring matter known as immedial - indone gives a dicarboxylic derivative, C17H1404N2S2 (Found, M. W. = 377), which requires, for its reduction to the leucocompound, two atoms of hydrogen per molecule. The suggested constitution for this dicarboxylic derivative is— N 249. "The Constituents of Leptandra." By FREDERICK BELDING POWER and HAROLD ROGERSON. (Trans., 1910, 1944). The material employed for this investigation was commercial "leptandra," consisting of the dried rhizome and roots of Veronica virginica, Linné (Leptandra virginica, Nuttall). the A concentrated alcoholic extract of this material, when distilled in a current of steam, yielded a small amount of an essential oil. The latter was a dark coloured liquid, which distilled between 120° and 160°/25 mm. The portion of extract which was soluble in water contained 34-dimethoxycinnamic acid, of mannitol, amounting to 2'14 per cent of the weight of C6H3(OMe)2 CH:CH CO2H (m. p. 180-181°); a quantity the drug; and a sugar which yielded d-phenylglucosazone (m. p. 209-211°), together with tannic and colouring matter. It yielded, furthermore, a quantity of an amorphous product, which possessed an intensely bitter, nauseous taste, and amounted to 1.6 per cent of the weight of the drug. By the hydrolysis of this product there were obtained, besides resinous material, cinnamic and p-methoxy cinnamic acids. consisted chiefly of a dark brown resin, which amounted The portion of the extract which was insoluble in water to 6.2 per cent of the weight of the drug. From this resin the following substances were obtained:-A phytosterol, C27H460 (m. p. 135-136°); [a]D-330°), the acetate of designate verosterol; a mixture of fatty acids, consisting which melts at 119-120°, and which it is proposed to apparently of oleic, linolic, palmitic, and stearic acids; P-methoxycinnamic acid, OMe C6H4 CH: CH CO2H (m. p. 170°), which was present in the form of an ester, and a very small amount of 3: 4-dimethoxycinnamic acid. It has not been possible to confim the statement recorded in the literature that "leptandra " contains a crystalline bitter glucoside, designated as "leptandrin," to which its activity may be attributed, nor does it contain a saponin, as has been asserted. 250. "The Formation of Tolane Derivatives from p-Chlorotoluene and 3: 4-Dichlorotoluene." By JAMES KENNER and ERNEST WITHAM. (Trans., 1910, 1960). The anomalous formation of a tolane derivative during the preparation of benzotrichloride from toluene, described by Liebermann and Homeyer (Ber., 1879, xii., 1971), was also observed by Armstrong and Wynne during the conversion of p-chlorotoluene and of 3: 4-dichlorotoluene into the corresponding chlorobenzylidene dichlorides. The A description is given of the nitration of triphenylstibine, I present authors have investigated these toluene derivatives 247. "Aromatic Antimony Compounds. Part I. The Oxidation and Nitration of Triphenylstibine." By PERCY MAY (Trans., 1910, 1956). with the view of determining the conditions leading to their | the aliphatic alcohols and acids. The aromatic amides, formation. benzamide, and salicylamide are strongly associated. Below 80°, formamide is more highly associated than water, but the molecular complexity decreases rapidly with rise of temperature. To aid in the study of this condensation, 4: 4′-dichlorotolane tetrachloride has been obtained by the action of copper powder on p-chlorobenzotrichloride. The method gives only moderate yields, and, as previously found by It was concluded that the cause of molecular association Fox (Ber., 1893, xxvi., 653), and now confirmed by the in the amides cannot be directly ascribed to the unsatuauthors, breaks down when applied to the case of o-chloro-rated character of the nitrogen or oxygen atom, and that benzotrichloride. association only occurs when these elements are found in combination in electronegative groups. ROYAL SOCIETY. Ordinary Meeting, November 10th, 1910. cis- and trans-4 : 4′-Dichlorotolane dichlorides, melting at 166-167 and 86-87° respectively, result from the action of zinc dust on the tetrachloride in alcoholic solution at 50° for two days, although under these conditions some of the cis-isomeride is further reduced to 4:4'-dichlorotolane (m. p. 175-176°), whilst at the boiling-point the conversion is complete. Both the cis-2: 2'- and 4: 4'-di- Sir Archibald GEIKIE, K.C.B., President, in the Chair. chlorotolane dichlorides under similar conditions give the corresponding dichlorotolanes. 251. "The Effect of Temperature on the Equilibrium 2CO CO2+C." BY THOMAS FRED ERIC RHEAD and RICHARD VErnon Wheeler. The equilibrium between carbon monoxide, carbon dioxide, and carbon has been determined for every 50° between 850° and 1100° and for 1200°. The method adopted has been to circulate carbon dioxide continuously over purified wood charcoal heated in an electric resistance furnace of special construction until the pressure in the apparatus attained a constant value. The values obtained for the equilibrium are as follow:Per cent by volume. Carbon dioxide. Temperature. Carbon monoxide. 252. "The Molecular Complexity in the Liquid State of Tervalent Nitrogen Compounds." By WILLIAM ERNEST STEPHEN TURNER and ERNEST WYNDHAM MERRY. The molecular complexities of nearly forty organic nitrogen compounds, comprising amines, nitrosoamines, nitriles, and amides have been determined by Ramsay and Shields' method; one, and the main, object of the investigation being to ascertain if the molecular association in the amides can be ascribed to the action of the unsaturated valencies of the nitrogen or oxygen atom present in the amido-group. Primary amines were found to be slightly associated. Secondary and tertiary amines gave abnormally high values of the Ramsay and Shields' constant, and the results raised the question of the validity of the Ramsay and Shields' formula. The aliphatic nitrosoamines and aliphatic nitriles are associated; the aromatic members of these two groups of compounds are either only slightly or non-associated. The amides and anilides examined are associated, the extent of association being of the same order as found in PAPERS were read as follows: "Tidal Observations of the British Antarctic Expedi tion, 1907.' by Sir GEORGE DARWIN, K.C.B., F.R.S. "A Mistake in the Instructions for a certain Apparatus in Tidal Reductions." By Sir George Darwin, K.C.B., F.R.S. "Conduction of Heat through Rarefied Gases" (II.). By FREDERICK SODDY, M.A., F.R.S., and ARTHUR JOHN BERRY, B.A. The thermal conductivities of argon, helium, and hydrogen at very low pressure have been examined in greater detail with new and improved apparatus. The hypothesis provisionally put forward (Proc. Roy. Soc., 1910, A, lxxxiii., 254) that the interchange of energy on impact is imperfect in the lighter gases, has been tested and found not to account for the smallness of the ratio (K/Q) of the found to the calculated conductivities. The conductivity of hydrogen using a palladium hot wire is the same as that with a platinum wire. Change of temperature of the hot surface, that of the cold surface remaining constant at room temperature, does not exert so much influence on the value of K as was anticipated. The value of K/Q tended to diminish as the difference of temperature increased, especially at high temperatures. At low temperatures, attained by immersing the apparatus in liquid air and in solid carbon dioxide and ether, the ratio K/Q is diminished, whereas on the hypothesis of imperfect interchange of energy an increase was expected. Jacketing the apparatus with vapours up to 264° caused an increase in the value of K/Q. It appears that, most probably, increase in the difference of temperature between the surfaces tends to decrease the value of K/Q, whereas increase in the temperature of both surfaces increases it. Argon under some of the new conditions tried conforms to the theory hardly better than the other gases, and the agreement found previously was probably fortuitous. The general conclusion is that the conductivity at low pressures varies less with the nature of the gas and with the temperature of the experiment than is to be expected from kinetic considerations. The extreme values found for the conductivities of the three gases over a range of about 450° lay between o8 and 34, whereas the calculated values lie between o'95 and 16:2 (X 10-5 calorie, per sq. cm. of hot surface, per 1° difference of temperature, per oor mm. pressure of gas). "Chemical Physics involved in the Precipitation of Free Carbon from the Alloys of the Iron-Carbon System." By W. H. HATFIELD, B.Met. The intention of the author is to examine the conditions under which free carbon is produced in iron and steel. Whereas it has been an open question as to whether or not free carbon could be produced direct from the solid solution, the paper is intended to prove the truth of the theory that free carbon can only be produced by the dissociation of the free carbide. It is hoped to demonstrate that this theory holds good through the whole range of the alloys in which free carbon, whether as graphite or annealing carbon, is found. NEWS After the presentation of evidence in support of this view of the production of graphite in and near the freezing range, experiments, performed to determine the chemical physics underlying the liberation of annealing carbon in white cast-iron, are described. By the electrolytic method of analysis the cementite carbide was obtained from such irons of varying composition, and it is shown how, by varying the percentage of silicon, manganese, or sulphur in the iron, the composition of the cementite is modified and its degree of stability at varying temperatures determined. It is also shown that the size and structure of the precipitated annealing carbon is largely due to the size and structure of the original cementite. Experiments performed to produce annealing carbon in blister steel during the cementation process are then described; after which an expla, ation of the phenomena of "black" stee! is discussed; it is shown that the free carbon found in such steels may present one of two formations, each produced under different conditions. The author further endeavours to demonstrate that whilst the free cementite carbide is dissociated at high temperatures through the whole range of the alloys, the carbide remaining in solid solution does not dissociate until the resolution of the solid solution into the carbide and iron of the pearlite, at the carbon change point. 66 Spectroscopic Investigation of the Nature of the Carriers of Positive Electricity from Heated Aluminium Phosphate." By F. HORTON, M.A., D.Sc. The emission of positive ions from substances heated in a vacuum has been investigated by several experimenters, and it has been found that the ratio of the charge to the mass of the ions is the same for all the substances so far experimented on. Assuming that the charge is equal to that carried by the hydrogen ion in electrolysis, the mass of the carriers of positive electricity from heated substances must be about twenty-six times that of the hydrogen atom. The object of this research was to obtain the spectrum. of these ions. Aluminium phosphate was chosen for investigation because of the very large positive ionisation produced on heating this substance. A calculation showed that, with the apparatus used, it might be expected to collect a sufficient quantity of the carriers to obtain their spectrum in a small vacuum tube. The vessel used to collect the carriers was cooled in liquid air during the passage of the thermionic current from a strip of platinum covered with aluminium phosphate to a surrounding platinum cylinder. The material collected was then allowed to vaporise and its spectrum was obtained by rendering it luminous with an electrodeless ring discharge. The spectrum of carbon monoxide was always obtained, although precautions had been taken to exclude this gas, or materials which might give rise to it, from the apparatus. It is concluded, therefore, that the positive ions consist of carbon monoxide, the molecular weight of which agrees fairly well with that required by the results of the e/m determinations. "Anomalous Behaviour of Delicate Balances, and an Account of Devices for Increasing Accuracy in Weighings." By J. J. MANLEY. in Space." By Prof. F. W. DYSON, F.R.S. "Conditions Necessary for Discontinuous Motion in Gases." By G. I. TAYLOR. "The Radium Content of Basalt." By the Hon. R. J. STRUTT, F.R.S. duced in Thorianite and Pitchblende, with a Minimum "Measurements of the Rate at which Helium is proEstimate of their Antiquity." By the Hon. R. J. STRUTT, F.R.S. PHYSICAL SOCIETY. Ordinary Meeting, November 11th, 1910. Prof. H. L. CALLENDAR, F.R.S., President, in the Chair. The question of the simultaneity of magnetic disturbances recorded at different stations has recently been discussed by Dr. Bauer and Mr. Faris. A good many magnetic storms have so-called "sudden commencements." As regards these "sudden" changes three things are conceivable; they may be absolutely simultaneous at different stations; there may be a very small difference of time corresponding to the rate of propagation of electromagnetic waves; or, finally, there may be, as Dr. Bauer concludes, longer intervals, amounting to several minutes, for stations remote from one another. Dr. Bauer concludes that Mr. Faris's figures demonstrate the truth of his theory that dis.. turbances normally are propagated round the earth, sometimes eastward sometimes westward, the time of a complete revolution averaging about three and three-quarter minutes. The author of the present paper discusses the weaknesses of Dr. Bauer's theory. He points out that the theory could be adequately tested by a careful comparison of curves from selected stations fairly encircling the globe, choosing if possible stations whose time-measurements are specially reliable. A paper entitled "On Cusped Waves of Light and the Theory of the Rainbow," was read by Prof. W. B. MORTON. Diagrams were shown of the forms assumed by a planewave of light falling on a spherical raindrop and twice reflected from the interior of the drop, as well as the waves emerging from the drop. The waves in general have cuspidal edges which run along the caustic surfaces. This relation between the caustic and the cusps on the waves was pointed out by Wood in connection with the similar waves produced by reflexion at a spherical surface. It had been noticed earlier by Potter, Jamin, and Macé de Lepinay. The phase over a wave of this type is not conStant, the two portions on opposite sides of a cusp differing in general by a quarter period. Attention was drawn to the advantage of regarding the distribution of light in the rainbow as the consequence of the interference of the the direction of minimum deviation. This way of looking cusped waves which run down to the observer's eye along at the matter is shown to be equivalent to Mascart's approximate method of explanation of the formation of the supernumerary bows by interference of disturbances coming from the two poles on the special wave-form used by Airy. disturbance as it passed through the drop would be subject Prof. C. H. LEES pointed out that the boundary of the to diffraction effects. He asked if this would make any material difference in the results arrived at in the paper. The AUTHOR, in reply, stated that diffraction pheno "Aerial Plane Waves of Finite Amplitude." By LORD mena would not seriously affect the diagrams he had RAYLEIGH, O.M., F.R.S. It is considered improbable that this gas is evolved on heating every substance which has been experimented on in the determinations of the specific charge, but from the nature of the apparatus used, it must always have been present during these determinations. In the paper, reasons are given for believing that molecules of carbon monoxide readily act as carriers of positive electricity, and this gas probably diffuses into the hot metal or other substance and is evolved in an ionised state. "Determination_of_the_Tension of a Recently-formed Water-surface." By N. BOнr. Arguments in further support of the author's previous conclusion, that the surface tension does not change sensibly with the time that has elapsed since the surface was formed. obtained. |