ii. 33 General and Physical Chemistry. The Ideal Refractivities of Gases. WILLIAM JACOB JONES and JAMES RIDDICK PARTINGTOX (Phil. Mag. 1915 [vi] 29 28-35).-A full account of work of which an abstract has already appeared (P. 1914 30 201). The Magnetic Field of an Atom in Relation to Theories of Spectral Series. H. STANLEY ALLEN (Phil. Mag. 1915 [vi] 29 40-49).-On the assumption that the atom may be regarded as a central core carrying an electric charge and producing a mag- netic field similar to that due t o an elementary magnet the core being surrounded by electrons in orbital motion it is shown that a formula for the distribution of lines in spedral series may be derived which is of the same type as the Ritz formula. The energy of radiation as in Bohr’s theory is supposed to be given out in quanta which represent the differences between the energies in two steady st’ates of motion.From a consideration of the numerical values of the constants in the derived formula i t is found however that the magnetic forces set up by the atom are insufficient to account f o r more than a small fraction of the effect that would be necessary t o give the observed distribution of lines in spectral series. The Series Spectrum of Hydrogen and the Structure of the Atom H. STANLEY ALLEN (Phil. Mag. 1915 [vi] 29 140-143. Compare Curtis A 1914 ij 761).-According to) the measurements of Curtis the series lines of hydrogen cannot be exactly represented by Balmer’s formula. An attempt has been made t o ascertain whether the inclusion of the effect of a magnetic field (compare preceding abstract) would lead t o results in agreement with observation.The result of this inquiry shows that it is possible to’ account for the series spectrum of hydrogen on the lines of Bohr’s theory if i t is assumed that the core of the atom can pro- duce a magnetic field equivalent t o that set up by either five or six magnetons. I n support of the number 5 is the fact that the mag- netic moment produced by an electron moving in a circular orbit with angular momentum h/2n is exactly 5 magnetons. On the other hand tlhe hypothesis of a core of 6 magnetons appears to be supported by the diamagnetic properties of hydrogen. Spectroscopic Investigations in Connexion with the Active Modification of Nitroger. IV. A Band Spectrum of Boron Nitride WILFRED JEVONS (Proc.Roy. Soc. 1915 [ A ] 9 1 120-134. Compare A. 1913 ii 813).-When the vapour of boron trichloride is introduced into active nitrogen a very pale bluish-green glow is obtained the d o u r of this being very readily distinguishable from the vivid green of the boron flame. The investigation of the spec- H. M. D. H. M. D. H. &I. D. VOL. CVIII. ii. 3ii. 34 ABSTRACTS OF CHEMICAL PAPERS. trum of the glow has shown that i t consists of the three boron lines A 3451'50 h 2497.83 and A 2496.89 and of a new system of bands with well-defined heads degraded towards the red end which extend from A6371 to at least h2140. The same band spectrum is obt'ained when methyl borate is allowed to come in contact with active nitrogen. Analysis of the spectrum indicates that it contains two distinct systems in the less refrangible of which each band consists of four heads forming two close doublets whilst the more refrangible system is characterised by single-headed bands and thus resembles the band spectrum of silicon nitride described in a previous paper.These bands are not observed in a vacuum tube containing the vapour of boron trichloride and evidence has been obtained that the band spectrum is duel t o boron nitride. Boron carbon and silicon com- pounds behave similarly therefore in that all give rise t o nitride spectra in the nitrogen after-glow. The boron nitride bands like the cyanogen bands are produced in the arc spectrum where they occur together with the headless wavy bands of the oxide. Measurements of the wave-lengths of the heads of the bands are recorded and formulz have been deduced t o represent them.H. M. D. The 8pectrurn of Palladium. EMIL PAULSON (Phil. Mag. 1915 [vi] 29 154-157).-A discussion of the relations exhibited by the wave-numbers of lines in the palladium spectrum. It is shown that a large number of lines fall into four vertical groups the corre- sponding members of which exhibit constant differences in the wave-length numbers. Denoting the four groups by A B C and D the wave-numbers of these lines are represented by the relations B=A+ 1628'33 C=A+3968.00 B=d 4-5159-14. The Absorption Spectra of Organic Substancee in the Light of t h e Electron rheory. N. P. K. J. O'N. MCCLELAND (Phil. Mag. 1915 [vi] 29 192-206).-A theory of absorption is put forward which is based on certain views relative t o the constitution of the atom and it is claimed that this theory makes it possible t o predict with reasonable accuracy the positions of the absorption bands of organic compounds from the constitution when certain fundamental constants are given.I n the model of the atom from which these results are obtained i t is supposed that the valency electrons move in circular orbits round a central nucleus. The radius of the orbits is influencled by the mode of combination of the atoms in the mole- cule and when light is allowed t o act on the system the electrons are caused t o vibrate in their appropriate orbits. Since an electron moving in an orbit represents an electric current the vibrations of one will affect those of another in accordance with the laws of electrodynamics and the problem of ascertaining the position of an absorption band is therefore reduced t o compounding such vibrations by the mutual induction method.The method is applied t o a number of different systems contain- ing respectively one two three and four vibration centres and H. M. D.GENERATJ AND PHYSICAI; CHENISTRY. ii. 35 also to the benzene system in which there are six identical vibra- tion centres arranged in a ring. Other atomic systems correspond- ing with more complex aromatic compounds are also briefly coil- sidered. I n this way a number of constants have been derived with the aid of which it has been possible t o locate the positioii of the absorption bands in a considerable variety of organic corn- pounds.Except in the case of very complex substances the diner- ence between the observed and calculated positions is as close as can be expected. Quantitative Meaaurements of the Absorption of Light. I. The Molecular Extinctions of the Saturated Aliphatic Ketones. PRANCIS OWEN RICE (Proc. Roy. SOC. 1914 [ A ] 91 76-42. Compare Stewart and Baly T. 1906 89 489).-The ultra-violet absorption of fourteen saturated aliphatic ketones has been investigated. I n most cases the ketones were purified by conversion into the bisulphite compounds in others by transformation into the semi- carbazones. The experimental data show that the wave-lengths of the centres of the absorption bands depend on the number of methyl groups in the u- and @-posit'ions relative to the carbonyl group.Snbstitu- tion of hydrogen atoms in the y or further positions has no influence on the position of the band. For ketones of the general formula C€I,*CO*CW,-CH,R in which R is a saturated alkyl radicle the position of the centre of the band is a t ~ 2 7 9 0 and for those represented by the formula RCH,*C1FI,*C0.CH,*CH2R the centre is a t A 2820. The substitution of an a-hydrogen atom by methyl causes the centre of absorption t o shift towards the red and from the data for acetone methyl ethyl ketone methyl isopropyl ketone and pinacolin i t is found that the shifts corresponding with the successive substitution of the three a-hydrogen atoms are 23 50 and 30 Angstrom units respectively. The author considers that these measurements show the existence of a relationship between the optical and the chemical properties.The general results exhibit a certain parallelism with the observations on Lhe magnetic rotation of the ketones for whereas the magnetic rotatory power is normal in the case of methyl isopropyl ketone and the higher homologues it is abnormal for methyl ethyl ketone and still more abnormal for acetone. Spectrophotometric measurements of the extinction-coefficient (E) have also been made and these data show that the molecular extinctdon M=E/c where c is the molar concentration of the ketone has the same value (21.2) f o r all the ketones examined with the exception of acetone and methyl ethyl ketone. Moreover the molecular extinction curves are1 absolutely identical for ketones of the general formula CH,*CO*CH,-CH,R whilst f o r the remainder excepting acetone and methyl ethyl ketone the curves are geo- metrically similar. On the assumption that the smaller absorption power of acetone is due to association the author obtains 1.24 f o r the association €1.M. D. 3-2ii. 36 ABSTRACTS OF CHEMICAL PAPERS. factor. This is in close agreement with the value 1.26 derived from the temperature-coefficient of the molecular surf ace energy. I n a similar way the association factor of methyl ethyl ketone js found t o be 1.09. The observations are said t o be in agreement with the theory that' the ultra-violet absorption is due to the electromagnetic field of the carbonyl group as influenced by the substituents in the immediate neighbourhood. H. 11.D. Coloration of Some Derivatives of Picrglmethylamine with Alkalis. A. P. N. FRANCHIMONT and H. J. BACKER (Proc. K. Akad. Wetensclh. Amstsrdarn 1914 17 647-653).-1n continuation of an investigation of the colour of picrylalkylnitroamiiies (A. 1914 ii 84) the authors have investigated the absorption of alcoholic solu- tions of a number of derivatives of pirrylmethylamine of the general formula C,H,(NO,),*NMe*X i n wliich X represents one of the groups KO COMei C02Me CO,Et C,H,. As was found in the case of the nitro-group the nitroso- and the acyl-groups greatly diminish the colour of picrylmethylamine and according t o the absorption curves the absorption bands a t 1 / A = 2390 and 2875 com- plet'ely disappear. The same effect is observed if picrylmethyl- amine is dissolved i n concentrated sulphuric acid.On addition of alkali the absorption curves for the acyl deriv- atives show well-marked bands with their heads a t about l/h=2000 and 2350 which are therefore practically identical with the bands exhibited by picrylmethylnitroamine. Plienylpicrylmethglami~~e in the absence of alkali shows an absorption in this region but the addition of alkali intensifies the absorption? and the curve for the alkaline solution shows maxima a t l/h=2070 and 2400. The ebsorption curve for picrylmethylnitrosoarnine in alkaline solution indicates that it is rapidly decomposed with the formation of the picrate of the alkali metal. The same change occurs with the acyl derivatives but much more slowly. The authors consider t h a t the absorption.bands are due to the interaction of the base with one o r more of the nitrogoups of the benzene nucleus. Confirmation of the Law of Bunsen and Roscoe for the Photochemical Reaction of Hydriodic Acid. E. JIrYrENo GIL (Anal. Fis. Quim. 1914 12 534-539).-8 fitudy of the photo- chemical oxidation of hydriodic acid. The results are in agreement with the law of Bunsen and Roscoe it=const. in wliich i repre- sents the intensity of the illumination and t its duration. Both an electric arc and a mercury vapour lamp were employed as the source of light. Organic Syntheses by means of Sunlight. XI. General Considerations. E. PAT ERN^ (Gazxettct 19 14 44 ii 463-475)- The author mrns up in general terms the results of his investi- gations on this subject during the past' six years.The principal types of readion observed t o occur under the influence of sunlight are as follows 11. &I. D. A. J. W.GENERAI AND PHYSICAL CHEMISTRY. ii. 37 (1) Carbonylic compounds such as aldehydes and ketones react on olefinic hydrocarbons with rupture of the double linking of the latter and formation of the closed-chain trimethylene oxide and its derivatives This so-called trimethylenic condensation takes place generally but not universally and does not occur with oxygenated compounds other than aldehydes or ketones. (2) Ketones react with aromatic hydrocarbons and other aromatic compounds thus 2C,,H1,0 + 2C,H,Et -+ C,,H,,02 + CHPhMe-CHPhMe the ketone undergoing reduction t o pinacone. This doubling of the carbon atom chain takes place also with such compounds as P-phenylpropionic acid which forms j3 y-diphenyl- adipic o r ap-dibenzylsuccinic acid.I n no instance has the1 author been able to prove the union of two aromatic nuclei in this way (see A. 1914 ii 321; Ciamician and Silber A. 1912; i 537). (3) Between ketones and aromatic hydrocarbons and other aromatic compounds a second reaction occurs at the same time as and perhaps more generally than the preceding one. In this direct addition takes place with formation of a tertiary alcohol benzophenone and phenylacetic acid f o r example yielding aflfl-triphenyl-lactic acid. This change termed enolic condensa- tion takes place principally between the carbon of the ketonic carbonyl and the methylene group the aromatic nuclei playing no part. Enolic condensation is observed also between bases and ketones benzophenone giving with benzylamine the compound OH*CPh,*CHPh*N€I with nicotine a new alkaloid C,,H13N CP h 2* 0 €1 and with p-toluonitrile the compound OH*CPh2*CH,-C6H,*CN.(4) Further ketones react with hydrocarbons more especially with the paraffins and with some of their derivatives in a manner which has not yet been clearly characberised (compare A. 1909 i 240) but probably consists in the conversion of two mols. of the ketone into pinacone and the union of a third molecule of ketone with one of the paraffin t o form an oxytrimetliylene coinpoutid 3C,3Hlo0 + C,H +2 = CU,,H,,O + C'lsHl,O:C,H,,,. This reaction is given also by cyclic hydrocarbons and by ethers acetals and similar compounds. The formation of numerous synthetlic resins the preparation of colloidal substances from sparteine and from strychnine the trans- formation of pyrone into a carbohydrate similar t o the pentosans the formation of nitrogenous organic compounds by the reduction of nitrates the synthesis of photo-acetophenone and its analogues and the possibility of introducing complex side-chains into the molecules of the vegetable alkaloids with formation of derivatives of pharmacological applicability are all important points resulting from the author's investiga.tions.T. H. P. Reduction of Aromatic Ketones. 111. Photochemical Phenomena. J. BOESEKEN and W. D. COHEN (Proc. K. Akad Wetensch. Amstevdaml 1914 17 849-870. Campare A. 1913 i 1062).-The reduction of an aromatic ketone in a perfectly neutralii.38 ABSTRACTS OF CHEMICAL PAPERS. medium dom not proceed any further than t o the pinacone. A series of ketones dissolved in a great variety of anhydrous alcohols and a few other substances have been exposed t o sunlight or t o the light of a mercury lamp; in all cases where reduction occurs not a trace of the hydrol is formed the ketones being quantita- tively changed to the pinacones. The addition of sodium ethoxide to the alcoholic solution results in the formation of the hydrols as is t o be expected (Zoc. cat.). The authors deduce therefore that in the reduction of aromatic ketones the hydrogen unites ex- clusively with the oxygen ; the resulting half-pinacoiie polymerises to the pinacone and the latter in the presence of hydroxyl ions is transformed into an equal molecnlar mixture of the ketone and the hydrol.Water acts as a powerful negative catalyst; in 80% alcohol reduckion of benzophenone does n o t occur after exposure for months whereas in absolute alcohol under the same conditions 40% of benzopinacone is obtained after ten hours. The reduction of benzophenone has been investigated in methyl ethyl propyl isopropyl isobutyl mheptyl sec.-octyl hexadecyl allyl benzyl and cinnarri yl alcohols in geraniol cy clohexanol benzhydrol and in fl-methylbutan-fl-ol y-methylpentan-7-01 and 6-methylheptan-8-01. Reduction does not occur in hexadecyl or cinnamyl alcohol proceeds very slowly in the last. three alcohols and in geraniol; and takes place rapidly and quantitatively in the saturated alcohols ; the reaction in methyl alcohol however (and also in allyl alcohol) is milch slower than in the other primary and secondary alcohols.Under the influence of light toluene or cyclohexane reduces benzophenone whilst hydrogen itself does not. By employing a constant source of light and allowing this to act on the different solutions under the same conditions relatively quantitative results are obtained. The experiments lead t o the following generalisations. The velodity of pinacme-f ormation appears to be independent of the concentration of the benzo- phenone and proportional t o that of the alcohol. The temperatare- coefficient is small 1*06-1+11 per loo. The velocity is greatly dependent on the ketone; benzophenone is attacked rapidly most of the other aromatic ketones as yet examined are reduced less rapidly and many of them are not reduced a t all..The ratio of the velocities of pinacone-form ation in different alcohols is constant. The ratio of the velocities of pinacone-forniation in sunlight and in the light of the mercury lamp is the same. When two ketones are present in one solution one of them absorbs a part of the rays required by the other; the same is true when the light passes through a solution of the one ketone and falls on that of the other. The light which is active in the reduction of aromatic ketones is situated in the spectrum between 400 pp and 430 ,up and very probably in o r adjacent to the rays 404'7pp and 407.8pp of the mercury lamp. c. s.GENERAL AND PHYSICAL CHEMISTRY. ii. 39 Acquired Radioactivity.SIR W ILLJAM CROOKES (Phil. Trans. 1914 [ A ] 214 433445).-Experiments extending over several years are described on the action of radium and its emanation on various substances with especial reference t o the diamond. Bom- bardment of a large number of crystals and phosphorescent sub- stances by cathode rays in a vacuum confers no radioactivity on them and the substance both t o electrical and photographic tests remains inactive. The phosphorescence of the diamond under the action of radium is due to the P- and y-rays but these produce no coloration. Placing a diamond in contact with a radium com- pound for long periods produces a coloration usually bluish-green which is an effect of the a-rays. Diamonds so treated acquire an enduring activity in which no apparent diminution occurs after ten years and neither the colour nor the radioactivity is removed by long treatment with a hot mixture of potassium chlorate and nit'ric acid.After being cut the diamond became quite colourless and free from radioactivity. Experi- ments with glass quartz and other materials buried in radium preparations for long periods and deeply coloured by the action of the rays showed that the diamond behaves differently from other substances and alone retains its acquired radioactivity after chemical treatment. Lead glass so treated became almost inactive after boiling in dilute nitric acid but diamond retained the greater part of its activity after boiling with fuming nitric acid mixed with potassium chlorate. A difference also appeared in the distribution of the radiations from the surface.A quartz crystal rendered radioactive and laid on a photographic plate gave an image of the geometric pattern arising from the superficial activity of the kind studied by Rutherford but the image from a radioactive diamond suggested rather a brush discharge from the corners of the crystal. The activity so acquired consists of u- P- and y-rays. F. S. Application of the Theory of Allotropy to Electromotive Equilibria. 111. A. SMITS and A. H. W. ATBN (PY~Jc. K. A h d . 1f%tansch. Amsterdam 1914 17 680-694. Compare A. 1914 ii 165 420 611).-The theory of allotropy described in previous papers is applied in explanation of the phenomena of electrolytic polarisation and of the passive condition of metals. Experiments are described which are said t o support the view that the seat of the polarisation effects and of the passivity is not in the boundary layer separating the metal and the electrolytle solution but in the surface of the metal itself.For the most part the observations consisted in measuring the changes in the E.M.F. of cells of the type :-metal 1 salt solution [ calomel electrode after the metal had been subjected t o the action of acids of anodic or cathodic polarisa- tion or of bromine water. The metals used were cobalt nickel iron and chromium which according to previous experiments are characterised by the slow rate a t which the internal equilibrium is re-established when this equilibrium in the surface layer of the metal has been disturbed by electrolytic o r chemical action.ii. 40 ABSTRACTS OF CHEMICAL PAPERS.Under the influence of the above-mentioned agencies the four metals investigated become distinctly less electropositive as would be expected according to the theory put forward by Smits. Of particular interest are some of the observations made with iron. After anodic polarisation and after etching with strong nitric acid t'he potential difference between iron and 0.W-ferrous sulphate solution decreases fairly rapidly then remains constant f o r a time before beginning t o fall again. The temporarily constant pot,ential difference has the same value whether the passivity of the metal is brought about4 by anodic polarisation or by the action of strong nit'ric acid. It is claimed that none of the older views on passivity affords such a satisfactlory explanation of the observed facts as that which is based on the theory of allotropy.I n certain respects Finkel- stein's theory offers a certain resemblance t o the theory put for- ward by the authors but there is a fundamental difference between the two. Whereas Le Blanc's theory considers that passivity is determined by retardation of the process of ionic hydration the new theory attributes the effect t o retardation of changes occurring in the surface layer of the metal. H. M. D. Allotropy of Cadmium. IV. ERNST COHEN and W. D. HIELDERMAN ( PYOC. K. Akccd. Wetensch. Amsterdum 1914 17,638-641. Compare A. 1914 ii 652).-As a result of the examination of a large number of cells arranged according to the scheme electrolytic cadmium 1 cadmium sulphate solution 112.5% cadmium amalgam it has been found that some show an E.1M.F.a t 25O of 0.050 volt o'thers 0.048 volt and others again 0-047 volt. The E.M.F. of cells of the first group decreases spontaneously to 0.048 volt a t which value the E.M.P. remains constant. I n the expectlation that cells giving 0.048 volt would be found to contain &cadmium and those giving 0.047 volt a-cadmium two such cells were examined at' 2 5 O and 64.5O. The two cells were connected up so as to have an amalgam electrode in common and readings were taken until the E.M.F. became constant. The final readings show that the cell with the lower E.M.F. a t 25O has the higher E.H.F. at 64.5O. From this observation the authors draw the conclusion that the E.N.F.of 0.048 volt corresponds with P-cadmium; i t is also probable that the cell giving 0.047 volt contains a-cadmium and that giving 0.050 volt y-cadmium. H. M. D. Electro-deposition of Lead. F. C. MATHERS and B. W. COCKRUM (Met. and @hem. #fig. 1914 12 714-715; from J. SOC. Chem. Ind. 1914 33 1158-1159).-A smooth finely crystalline deposit of lead is obtained as follows. Twelve and a-half grams of aloes are shaken with 500 C.C. of warm water and the insolubls gum o r tar is dissolved in 25-50 C.C. of glacial acetic acid. The acid solution is added to thel bath which contains 100 grams of lead acetate and 40 grams of ammonium perchlorate per litre. AGENERAL AND PHYSICAL CHEMISTRY. ii. 41 current density of 3.6 amperes per sq. f t . for thick deposits and 7-2 amperes per sq.f t . for thin deposits may be used. With lead lactate or formate solutions the baths should contain 4% af lead as lactate or 2% as formate 1-576 of lactic or formic acid 4% of ammonium perchlorate and 0.25./; of Barbadoes aloes the mixture being warmed and filtered before use. A current density of 3.6 amperes per sq. f t . may be used. Sodium naphtha- lenesulphonate may be used instead of ammonium perchlorate. c. s. Hermann's Phenomenon. GEORGE STANLEY WALPOLE (PYOC. Roy. Xoc. 1915 [ A ] Q1,134-147).-1t has been shown by Hermann that when a current is passed from a dilute solution of a salt t o one more concentrated acid is liberated a t the boundary layer and that alkali is set free a t the same place when the current is passed in the opposite direction.These observations have been confirmed and extended by the author. The experiments were made with a special form of transport apparatus designed to facilitate the formation and investigation of the boundary layers. The results obtained show that the quantities of acid and alkali liberated bear no relation t o the quantity of electricity passed through the circuit. For all the neutral salts examined the acid is always liberated when the current passes from the more dilute to the more concentrated solution and the alkali when the current passes from the concen- trated t o the more dilute. Other conditions being the same the same quantity of acid and alkali is liberated whatever neutral salt is present in the solutions. The explanation suggested for this phenomenon is based on the difference in the velocity of the hydrogen and hydroxyl ions on opposite sides of the boundary layer.This difference is determined by the fall of potential per unit length which depends essentially on the conductivity of the two solutions. The quantities of acid and alkali set free can be calculated from the potentiad gradients in the two1 sclutions the time for which the difference of potential is maintained the resistance constant of the apparatus the dis- sociation constant of water and the mobilities of the hydrogen and hydroxyl ions. Actual experiments afford numbers which are in approximatie agreement wit'h the calculated quantities. H. M. D. Luminous Vapours Distilled from the Arc with Applications to the Study of Spectrum Series and their Origin.11 Hon. R. J STRUTT (Proc. Roy. Soc. 1914 [A] 91 92-103. Compare A. 1914 ii 599).-The vapour of mercury distilling from the arc into a vacuum exhibits luminosity when the vapour has traversed con- siderable distances beyond the range of the electric field of the arc. The luminosity may be caused t o disappear by application of an independent electric field and the' experiments described by the author were made in order t o elucidate the nature of this effect in mercury and certain other meballic vapours.ii. 42 ABSTRACTS OF CHEMICAL PAPERS. From experiments in which the conducting properties of the luminous jet were examined by means of an auxiliary electrical circuit it is found that the conductivity depends essentially on the shape and position of thel cathode and is independent of the position of the anode. The fall of potential is almost completely confined t o the immediate neighbourhood of the cathode.These facts indicate that the electrical properties of the glowing vapour are similar t o those of a flame which is characterised by the great mobility of the negative ions compared with the positive. The luminosity is not affected when the stream of mercury vapour passe6 the anode but is more or less completely quenched whm it reaches the cathode. AltJiough the removal of negative ions at the anode is incomplete it is considerable enough t o show conclusively that the luminosity is independent of the number of negative ions present. It lolloms from this that the luminous emission is not due t o recombination of ions and it is supposed that the luminous centres are positively charged ions which are survivors of those which are generated in the arc itself.Since the time required for the vapour to travel down the tube is of the order of 1/1000 of a second it must be assumed thab the ions remain luminous for what must be considered as a very consider- able interval of time. Experiments with the vapours of sodium potassium calcium magnesium zinc cadmium and thallium have also shown that the line spectra are extinguished when the luminous vapour passes through a negatively electrified net. I n some cases (sodium mag- nesium zinc) the lines of one series are more easily extinguished than those of another. Thus the sodium lines of the subordinate series are all influenced to about the same extent but thO D-line is much less affected.From this it is inferred that the centres of emission are not the same for the two series of lines. The luminous jets formed by arsenic and antimony are not quenched by passing through a negatively electrified net. The band spectrum exhibited by these elements is therefore pre- sumably due to uncharged centres whilst the band spectrum of magnesium hpdride is apparently emitted by positively charged centres. H. M. D. Emiesivity of Metals and Oxides. 11. Measurements with the Micropgrometer. GI-. K. BURGESS and R. G . WALTENBURG (J. Wushingto?z Acad. Sci. 1914 4 566-567).-1t has been found t h a t the micropyrometer described in a previous paper (ibid. 1912 3 No. 7) may be empIoyed for the determination of the mono- chromatic emissivities of substances in very small quantities (of the order of 0.01 gram) with an accuracy of about 1%.The data obtained with red light of wave-length h=O*65 p and h=0*55 p are recorded for a number of metals and metallic oxides the emissive powers being compared with that of solid platinum. The temperatiire-coefficient of the emissivity is very small for all the metals investigated and for most this coefficient is negligible. I n the case of the white metals the emissive powerGENERAL AND PHYSICAL CHEMISTRY. ii. 43 shows very little or no change a t the melting paint but there is a marked discontinuity for gold silver copper and uranium. The behaviour of palladium is anomalous in that the emissivity proper t o the liquid may persist after solidification thus affording an instance of an undercooling radiation effect).The fact that platinum shows a change in emissive power on melting is of some consequence since the Violle standard is usually defined in terms of the luminous radiation from platinum at its nielting point. H. M. D. Experiments with Liquid Helium. Preliminary Determina- tion of the Specific Heat and the Thermal Conductivity of Mercury at Temperatures Obtainable with Liquid Helium and Meamremeots of Thermo-electric Forces and Resistances for the Purpose of these Investigations. H. KAMERLINGH ONNES and G. HOLST (Proc. K. Akad. Wetensch. Amsterdam 1914 17 760-767. Compare A. 1914 ii 832).-As a reault of the investigation of a number of thermo-electric couples it is found that these are un- suitable for the measurement of temperature at liquid helium temperatures. I n accordance with theoretical anticipations the thermo-electric power of all the couples investigated approaches zero a t helium temperatures.On the other hand it is found that satisf actory measurements of temperature may be obtained with resistance thermometers of manganin and constantin. The apparatus employed in the measurement of the specific heat of mercury was similar t o that described by Nernst (A 1910 ii 263). The value obtained wzs 0.00142 f o r the mean specific heat between 4.26* and 6'48O (abs.) and 0.000534 between 2 * 9 3 O and 3-97O (abs.). By making use of Debye's formula for the variation of the specific heat c with the temperature 21 c=kT3 in which k is a constant the authors' data are compared with the results obtained by Pollitzer a t higher temperatures.It is found in this way that the specific heat a t helium temperatures cannot be satis- factorily represented by the formula in question. The measurements of the thermal conductivity gave k = 0.27 between 4.5O and 5*1° (abs.) and 0'40 between 3 ' 7 O and 3 . 9 O (abs.). No evidence of the discon_tinuity which is shown by the electrical conductivity olf mercury a t 4*19O (abs.) was found in the case of the specific heat or of the thermal conductivity. H. M. D. Heat of Fusion and the Periodic System. JULIO GUZMBN CARRANCIO (Anal. Pis. Quim. 1914 12 526-534).-The results of experiments on the heat of fusion of the elements indicate that the heat of fusion per gram is a periodic function of the atomic weight and for analogous elements of the same group of the periodic system decreases with increase of atomic weight.A similar periodicity is displayed by the quotients obtained by dividing the absolute temperatures of fusion by the atomic weights. The atomic heats of fusion do not exhibit a corresponding periodicity. A. J. W.ii. 44 ABSTRACTS OF CHEMICAL PAPERS. The Correction of about 1/66 in the Determination of the Freezing Point of Dilute Aqueous Solutions Supercooled by lo M. C. DEKHUYZEN (Chem. Weekblad 1915 12 24-28).-The author advances arguments and experimental evidence in support of his contention that a correction of about 1/66 should be de- ducted from the reading in cryoscopic determinations with aqueous solutions.The correction must be determined for each apparatus independently and the volume of solution employed should be 15-20 C.C. A. J. W. Determination of Vapour Tensions at Low Temperatures. E. JIMENO GIL (Anal. Pis. Quint. 1914 12 469-4S2).-An account 07 results obtained in the determination of vapour tension a t low temperature. The values obtained for each substance a t the highest and lowest point of observation on the absolute scale are ethyl alcohol 0*00126 (173.1O) and 0.8349 (243.1O) ; ethyl ether 0.005156 ( 1 6 0 . 1 O ) and 0.6963 ( 1 9 5 . 1 O ) ; toluene 0.00170 (183*1°) and 0.8937 (246'1O) ; acetone 0.00837 (18O*lo) and 0.8763 ( 2 1 2 - 1 O ) ; methyl acetate' 0.00354 (138*1°) and 0.6240 (213.1O). A. J. W. Variation of the Triple Point of a Substance with Hydro- static Pressure. ALFRED W.PORTER (Phil. Ma3. 1 915 [vi] 29 143-149).-Since the saturation vapour pressure of any liquid or solid is a function of the hydrostatic pressure it follows that the triple point will vary with change in the hydrostatic pressure. It is shown t h a t the variation of the triple-point temperature with hydrostatic pressure is equal t o the corresponding change of the melting point. Under atmospheric pressure the triple point is therefore identical with the melting point. 33. 14. D. The Surface Tension of Molten Metals. SYDNEY W. SMITH (J. Inst. Metah 1914 12 168-213).-The method used is that of measuring the depression in a capillary tube electric light carbon. Ths metal is melted in a plunibago crucible in an electric furnace a reducing atmosphere being maintained. The level is measured by means of an insulated steel wire which is lowered vertically into t;be carbon tube by a micrometer depth gauge until an elec- trical contact is made.The results are sufficiently concordant. The metals examined are mercury tin bismuth lead zinc anti- mony aluminium silver gold and copper. The1 surface tension of molten metals is a periodic function oE their atomic weight metals with the largest atomic volumes having the least surface tensions. The metals which are known to have the greatest effect in lessening the cohesion of gold are those which are nearest to' gold in atomic weight but with much larger atomic volumes and therefore lower surface tensions such as lead and bismuth.The effect of other metals in dilute solution on the surface tension of mercury is also a periodic function of their atomic weight (Schmidt A. 1913 ii 190). C . H. D.GENERAL AND PHYSICAL CHEMISTRY. ii. 45 Coefficient of Diffusion in Dilute Solutions. BASIL W. CLACK (Proc. Physical SOC. London 1 9 14 2 7 5 6-68).-The apparatus described in previous papers (ibid. 1908 21 863 ; 191 1 24 40) has been improved with the result t>hat accurate measurements of the diffusivity of salts in aqueous solution can now be obtained in a few days. The special feature of the apparatus consists in the suspension of flasks filled with the solution under examinatioii from the arms of a delicate balance in a large volume of water the t’emperature of which is kept consbant. Each flask is fitted with a battery of narrow tubes through wliich the salt diffuses upwards.The diffusion tubes attached t o t’he two flasks are of equal length but differ considerably in sectional area and ail arrangement is provided whereby the concentration of the solution is kept constant a t each end of the tubes. The actual maiiipula- tion during the process of diffusion consists in determining the rate of change in weight of the flasks which in the improved apparatus attains a constant value after a very short time. It is in fact possible t o obtain fairly accurate values for the coeficient of diffusion in experiments which only last one day. The results obtained show that a t 18O the coefficient of diffusion A?. 105) for potassium chloride increases from 1.388 in 0.05.N- solution t o 1.584 in 2*ON-solution; for potassium nitrate it de- creases from 1.453 in 0.05~7~- to 1.190 in 1’ON-solution; and for sodium chloride i t increases from 1.165 in 0*05.iV- to 1.253 in 2 O N - solution. H.31. D. W. J. JONES and J . R. PART- INGTON (Phil. Mag. 1915 [vi] 29 35-40).-The authors discuss the question of the influence of surface energy on the solubility of solids in liquids and on the formation and stability of super- saturated solutions. The’ theoretical argument indicates that the size of ‘(active ” particles of solid that is such as induce crystal- lisation in a given solution decreases with fall o r rise of tempera- ture according to whether the solid dissolves in its nearly saturated solution with absorption or development of heat.The spontaneous crystallisation of supersaturated solutions of the first more fre- qucntly occurring type when these are cooled below a certain temperature is attributed to this reduction in the size of the ‘( active” particle. At a sufficiently low temperature it may be assumed that the necessary size is only a relatively small multiple of the size of the molecule of the dissolved substance. The Widmanatkitten Structure in Alloys and Metals. N. T. BELAIEW (J. Inst. Net& 1914 12 46-55).-The Widman- statt’en structure which is characteristic of meteorites is not’ con- fined to alloys of iron. It may be produced either by transforma- tions in the solid state o r by crystallisation from solid solution. Several examples are given. The Metastable Continuation of the Mixed Crystal Series of Pseudo-Components in Connexion with the Phenomenon of Allotropy.A. SMITS (Proc. K. Bkad. Wetsnsch. Amaterdarn 1914 17 672-678. Compare A. 1914 ii 546).-A theoretical paper in A Theory of Supersaturation. H. M. D. C. H. D.ii. 46 ABSTRACTS OF CHEMICAL PAPERS. which the author discusses the transition from monotropy t o enantiotropy under the influence of pressure. It is also shown that a system which shows no sign of phase allotropy under its own vapour pressure’ may become monotropic when the pressure is raised and that’ enantiotropy may be exhibited a t higher pressures i n the absence of monotropy under the characteristic vapour pressure of the system. H. 3%. D. Gas Equilibria and a Test of van der Waals’ Formula.I. F. E. C. SCHEFFER (Pvoc. K Akad. Vetmzsch. Amsterdam 1914 17 695-703).-The formulz for the equilibrium constants of gaseous systems derived by van der Waals Sackur and Tetrode have been examined by reference t o the data for the system I 21. Or1 the assumption that the iodine molecule is represenbed by two spheres the masses of which are concentrated in centres separated by a distance d these formulz give limiting values for d equal t o 1.6 x 10-8 and 0.7 x 10-9 cm. van der Waals’ formula which takes into account the variability of the specific heat with the tempera- ture yields for the atomic distance d=0.82 x 1 0 - 8 cm. H. M. D. Unmixing in a Binary System for which the Three-Phase Pressure is Greater than the Sum of the Vapour Tensions of the Two Components.F. E. C. SC‘HEFFER (Proc. K. Akad. Vetensch. Amsterdam 1914 17 834-839).-1t has been shown previously (A. 1914 ii 40) that the three-phase pressure in the system hexane-water is greater than the sum of the vapour pressures of the pure components when the temperature is not far removed from the critical solution temperature. Further investigation of liquid pairs has shown that the same behaviour is exhibited by I f normal pentane” (a mixture of n- and iso-pentane) and water and also by benzene and water. The difference f o r the first pair increases from 0.4 atmosphere a t 150° t o 1.8 atl 187.1° which is the critical end-point. For the second pair the difference increases from 0.45 atmosphere a t 210° to 2.95 a t 267.8O (critical end-point). It is supposed t h a t the relation in question is characteristic OF systems f o r which the critical end-points are lower than the critical temperatures of the two components.Binary systems f o r which the critical end-point falls between the critical tsmperatures of the components do not exhibit the above relationship according t o the data which are available for examination. For such systems the three-phase pressure is less than the sum of the vapour pressures of the components. Equilibria in Ternary Systems XVII. F. A. H. SCHREINE- MAKERS (Pvoc. K Akad. Wetensch. Amsterdam 1914 17 767-782. Compare A. 1914 ii 807).-A further discussion of the equilibrium relations for the case in which two of the three com- ponents are volatile and in which a solid binary compound is formed by combination of the non-volatile with one of the volatile components.H. M. D. H. M. D.GENERAL AND PHYSICAL CHEMISTRY. ii. 47 Equilibria in the System Pb-S-0; the Roasting Reaction Process. \v. REINDERS [with P. GOUDRIAAN] (Proc. l<. Akad. Tvetensch. Arr~sterdam 1914 17 703-718).-1n order to obtain information in regard t o the nature of the changes which occur during the inanu- facture of metallic lead from galena by the roasting process the authors have investigated the equilibrium relations in the ternary system with lead sulphur and oxygen as components. For tho most part the experiments consisted in the deteriiiination of the vapour pressures air temperatures between 500° and 800° and in the examination of the solid phases present under varying con- ditions of temperature and pressure.The collective data indicate t h a t when sulphur dioxide is re- moved from a mixture of lead sulphide arid lead sulphate the following univariant systems characterised by the presence of three solid phases are successively met with (I) PbS-PbSO,- PbO,PbSO ; (2) Pb-PbS-PbO,PhSO ; (3) Pb-PbO,PbSQ,- 2Pb0,PbS04 ; (4) Pb-2PbQ,PbS04-3Pb0,PbS0 ; (5) Pb- 3PbO,PbSO,-PbQ. The metallic phase probably contains a little dissolved lead sulphide the proportion of which varies in the different equilibria. The vapour pressures corresponding with the five systems and the variation of the pressure with the tempera- ture are shown in a series of curves. From the vapour-pressure curve for the first system the authors find t h a t the thermal value of the reaction PbX+PbSO,= 2Pb+2S02 is -99,543 cal.The value calculated from the heats of formation of the compounds involved in this equation is -92,470 cal. a t 20°. H. M. D. Aspirin. I. Decomposition of Aspirin by Water. D. E. TSAKALOTOS and S. HORSCH (Bull. Soc. chin?,. 1914 [iv] 15 743-747). -A study of the rate of decomposition of aspirin by water alone or in the presence of certain acids. The velocity of tlie action was measured by determining the increase in acidity using X i 50- sodium hydroxide and phenolphthalein as indicator. The decom- position of aspirin by water is very slow a t the ordinary tempera- ture being compIete in about 100 days. Acids exert a catalytic influence on the decomposition which is accelerated by hydro- chloric and sulphuric acids. With acetic o r citric acid the action is accelerat’ed up to about the eighth day afLer which the velocity of the action is diminished. W. G. Number Relations Amongst the Elements. F. H. LORING (Chenz. ,!ews 1915 11 1 13-15).-A discussion of certain relations exhibited by a periodic arrangement of the elements which has been deseribed in the author’s “ Studies in Valency.” H. 31. D. Theory of the Metallic State. F. A. LINDEMANN (Phi2. Mag. 1915 [vi] 29 127-140).-A theoretical paper in which the author discusses tlie interpretation of the physical propertie@ of metals in terms of t’he electron theory. It is shown that the free electrons in a metal may not be treated as a gas for a gas can only be aii. 48 ABSTRACTS OF CHEMICAL PAPERS. good conductor of heat if its heat capacity is large. Experiment shows that the free electrons conduct heat well but t h a t their heat capacity is too small to be measured. I t is suggested that the free electrons forin a space-lattice corresponding with a crystal a t a very low temperature. The application of this view to thO int'erpret ation of the various phenomena which are exhibited by metals is considered in detail. It explains the exceptional behaviour of alloys and in general outline the photoelectric effect but special assumptions are necessary for the derivation of the Wiedemann-Franz law. H. &I. D. Goossen van Vreeswyck a Mining Engineer and Chemist of 250 Years Ago. W. P. JORISSEN (Chern. Weei%6Zad 1914 11 1075-1086; 1915 12 2&-30).-An account of the life and publi- cations of Goossen van Vreeswyck (ca. 1630-1690) celebrated for his investigations in the animal vegetable and mineral kingdoms in many parts of the globe. A. J. W.