ii. 101 General and Physical Chemistry. Spectr ochemical Investigations on P olynuclear Aromatic Compounds in Solution. F. KROLLZFEIFFER (Annulen 1923 430 161-229).-Largely a statement in tabular form of the numerical results of the author’s measurements of the refractive indices in various solvents of a large number of derivatives of benzene naphthalene anthracene and other polynuclertr systems (cf. following abstract). Spectrochemical Peculiarities and Constitution of Naph- thalene Anthracene Phenanthrene and Fluorene. K. VON AUWERS and F. KROLLPFEIFFER (Anizulen 1923,430 230-268).- In this paper the spectrochemical measurements referred to in the preceding abstract along with similar numerical data obtained a t earlier dates and some new measurements are collected together and discussed from the point of view of their bearing on the con- stitution of the various basic ring systems.The authors favour structures for naphthalene and anthracene in which only one ring has full aromatic character and the usually accepted structures for phenanthrene and fluorene. As regards the effect of sub- stitution in naphthalene on spectrochemical properties the con- clusions are drawn (1) that large increases in the specific refraction run parallel with large dispersion; (2) that the introduction of alkyl alkoxyl carbalkoxyl groups and halogens has but little effect either on the exaltation of the refraction or dispersion; (3) that the effect of halogens is greater than in derivatives of benzene and (4) P-derivatives have as a rule a stronger exaltation in specific refraction than the corresponding a-derivatives.C. K. I. C. K. I. “Aromatic” Carbon. K. VON AUWERS (Ber. 1923 56 [B] 69-76; cf. von Steiger A. 1921 ii 473; 1922 ii 616; von Auwers A. 1922 ii 98).-A further criticism of von Steiger’s hypothesis that an essential difference exists between aliphatic and aromatic carbon atoms. The regularities observed in the thermochemistry of aromatic hydrocarbons do not necessitate the supposition of the tervalency of carbon but are equally reconcilable with the quadrivalency of the element (cf. Wibaut A. 1922 ii 239). They do not necessitate the hypothesis that the C-C and C-H linkings in aromatic hydro- carbons are equivalent from the point of view of energy which moreover is not in harmony with the principle of the distribution of energy of combination adopted by von Steiger (loc.cit.). It is only proved that the mean energy of formation of the individual linkings can be regarded as equal for purposes of calculation; this is in harmony with the similarity in the constitution of the mole- cules but does not necessitate any particular assumption with regard to the nature of carbon in these compounds. VOL. CXXTV. ii. 5ii. 102 ABSTRACTS OF CEEMICAL PAPERS. From the spectrochemical point of view it is shown in detail that the molecular refractions of anthracene and phenanthrene differ from one another to a degree which is completely outside the limits of experimental error whereas they should be identical if von Steiger’s hypothesis is correct. In general von Steiger regards discrepancies between the observed values and those calculated with the aid of the “ normal ” equivalents as defects whereas the whole history of spectrochemistry shows that such discrepancies are of the maximum value in throwing light on the constitution of the compounds under examination.Von Steiger’s method of calculating the molecular refractions is quite unsuitable for the homologues of benzene since the difference increases with increasing number of side chains. Von Steiger’s conception of the peculiar nature of ‘‘ aromatic ” carbon rests on the work of Debye and Schemer on the crystalline structure of graphite the additivity of the heats of combustion of certain purely aromatic hydrocarbons and the supposed additivity of their molecular refractions.Arguments based on the two latter points have been shown to be invalid whilst Debye and Scherrer’s observations do not depend on the existence of two differing types of carbon atom but on the formation of different types of molecule owing to the differing mode of union of identical carbon atoms. Further exception is taken to the sharp difEerenti- ation of aliphatic and aromatic carbon since this is not justifiable on purely chemical grounds and can only be applied to two extreme types of compounds which are not chemically distinctly separated. H. W. The Molecular Refraction of Anthracene. F. &ow;- PFEJFFER (Ber. 1922 55 [B] 77-83).-The molecular refraction of anthracene dissolved in quinoline has been determined the calculations being made in accordance with the formula MrL=M[rLS x 100 / p - rLB( 100 -p) lp] in which M is the molecular weight of the dissolved substance rL its specific refraction accord- ing to Lorenz and Lorentz rL8 the specific refraction of $he solu- tion rLx that of the solvent and p the percentage of solute.The mean value Mg5=65-3; this is considerably higher than that’ observed by von Steiger (A. 1922 ii 616) for anthracene dissolved in naphthalene which is in agreement with the previous observ- ations of Chilesotti. The discrepancy does not appear to be attributable to the particular solvent used since the molecular refractions of the closely allied 1 -methyl- and 9-ethyl-anthracenes are almost identical when the determinations are made with the molten materials or with their solutions in quinoline or naphthalene.Re-determimtion of the molecular refraction of anthrscene dis- solved in naphthalene has given values which agree excellently with those observed when quinoline is used as solvent and are much higher than those found by von Steiger and Chilesotti; the error in the observations of the former appears to lie in the observation of the refractive indices t,he latter in that of the density.GENERAL AND PHYSICAL CHEMISTRY. ii. 103 The values obtained for the molecuIar refraction of phenanthrene dissolved in benzene or naphthalene agree with those observed by von Steiger and Chilesotti. Calculation of the Hydrogen Dissimilar Spectra from the Inner Movements of the Electrons. 11. E. FUES (2. Physik 1923 12 1-12).-A continuation of a theoretical discussion (this vol.ii l) in which it is shown that it is possible to calculate the terms of the Rontgen and optical spectra from the movements of the electrons in a central field of force and to derive the potential curve of the atomic field. The sodium spectrum is considered in detail and the terms in its spectrum are deduced from the potential curve. The agreement for the quantum numbers of the 3 4 5 61 3 4 5 62 33 P3 5 63 and 44 members which is within 3% is a demonstration of the correctness of the recent views on the origination of series spectra. W. E. G. FREDERICK SUMNER BRACKETT (Astrophys. J . 1922 56 154-161).-The radi- ation from the central section of a long discharge tube has been analysed by means of a rock-salt prism spectrometer and a sensitive vacuum thermo-junction.Three (probably four) additional mem- bers of the Paschen series have been observed as well as the first two members of a new series corresponding with ~ = N ( 1 / 4 ~ - l / m ~ ) where m=5 6. These two lines at A 4.05&0-03p and 2-63&0-02p are due according to Bohr's theory to an electron falling into the fourth from the fifth and sixth rings of the hydrogen atom. Certain unidentified lines are recorded and it was observed that with increase of current the first Paschen line increased in intensity more rapidly than Ha. New Bands in the Spectrum of Silicon. ANGEL DEL CAMPO and Josk ESTALELLA (Anal. Ph. Quim. 1922 20 586-588; cf. del Campo ibid. 1915 13 98).-Seven new bands are described in the spectrum of silicon. They occur between h 2255.85 8.and X 2146.0 8. and appear to be composed of lines of variable intensity. A complete list of the components of the silicon spectrum is given. H. W. Visible and Ultra-red Radiation of Hydrogen. A A. E. G. W. R. The Spectrum of Neutral Helium. W. M. HICKS (Nature 1923 111 146).-A criticism of the formula employed by Silber- stein (this vol. ii 46) to express the diffuse series HeD'. A. A. E. The Visibility of Individual Spectra. F. H. NEWMAN (Phil. Mug. 1923 [vi] 45 293-299; cf. this vol. ii 46).-The relative visibility of the spectra of the vapour from alkali amalgams a t 200" is affected by the nature of the electrical discharge through the vacuum tube. The spectrum of the alkali metal is always well developed with the ordinary uncondensed discharge but is completely masked by the mercury s ctrum when the condensed discharge is sufficient to impart higher velocities to the colliding electrons is used.With the latter b r e resulttlnt increase in electrical energy 5-3ii. 104 ABSTRAUTS OF CHEMICAL PAPERS. during their mean free path and to ionise the mercury atoms although these have higher ionisation potentials than the atoms of the alkali metals. The energy attained is sufficient to remove two or more electrons as is shown by the production of enhanced lines. W. E. G. Revision of the Series in the Spectrum of Strontium. F. A. SAUNDERS (Astrophys. J. 1922 56 73-83).-Measurements have been made of the spectrograms of light from a great variety of sources and revised wave-lengths are given for most of the 180 lines from 0.22 to 3.06 p including about 70 new lines. Accurate determinations have been made of the limits of all the series and the various terms have been calculated.About half of the twenty series mentioned are believed to be new and there is evidence of the existence of new types of singlet series corresponding with the formula? (1P)-(mX) (1p)-(mX) (1P)-(my) etc. The terms are all large so that the series cannot be of the kind suggested by Sommerfeld. In the case of calcium three singlet lines are found to correspond accurately with (12’)- (mX) ( lpl) - ( m X ) and (1p2)-(mX) where (mX) is 8584.8 thus indicating a series similar to that of strontium. A. A. E. Structure of the Spectrum of Scandium. MIGUEL A. CATALAN (AnaE. Pis. Quim. 1922 20 606-623).-The lines in the spectrum of scandium fall into two classes namely those forming doublets and those forming triplets.Sommerfeld’s displacement rule holds for scandium since its enhanced spectrum is analogous to the arc spectrum of calcium. The multiplets (cf. A. 1922 ii 726) are divided into ‘‘ multidoublets ” and “ multitriplets.” Com- plete lists are given of the lines in the spectra of the neutral and ionised atom respectively. The Structure of the Arc Spectra of the Elements of Columns VI and VII in the Periodic Table. &I. A. CATALAN (Compt. rend. 1923 176 84-85).-1t has previously been shown (A. 1922 ii 726) that the manganese spectrum shows three diffuse triplets consisting of nine rays instead of six due to the fact that the diffuse term d is quintuple instead of triple.It is now shown that this is not a property peculiar to manganese but is common to other elements. The arc spectrum of chromium is very complex and presents several systems of series. Two of these determined for the first time are tabulated. They are almost identical the one being displaced with respect to the other by a constant quantity C=4436.4. The diffuse terms are quintuple and give nine rays as for manganese. W. G. The Structure of the Spectrum of Chromium. A. DE GRAMONT (Compt. rend. 1923,176 216-217).-The author directs attention to the fact that he predicted that in the spectrum of chromium there would be two triplets one corresponding with the neutral atom and the other with the ionised atom and that this prediction has now found confirmation by the measurements made by Catalh (preceding abstract).G. W. R. W. G.GENERAL AND PHYSICAL CHEMISTRY. ii. 105 The Structure of the Arc Spectra of Molybdenum Selen- ium and Chlorine. M. A. CATAL~N (Compt. rend. 1923 176 247-248).-The arc spectrum of molybdenum is extremely com- plex. The diffuse term is quintuple and the number of rays is nine. The rays of the triplet of the principal series are the ultimate rays of Gramont. The diffuse triplets of selenium are regarded as exceptional by the number the intensity and the position of their satellites. The spark spectrum of chlorine shows triplets. The photograph of the spectrum shows the presence of a t least three components in the first ray although the tables give a number of components equal to 1+3+2.Thus the diffuse term of the elements of columns VII and VI of the periodic table is quintuple and the number of rays which form the diffuse triplets is nine. W. G. Coincidence Method €or the Wave-length Measurement of Absorption Bands. H. HARTRIDGE (Proc. Roy. Soc. 1923 [ A ] 102 575-587).-A spectroscope suitable for the measurement of wave-lengths of absorption bands is described. It is designed so that two similar spectra are produced lying side by side and reversed in direction to one another. For the measurement of the mean wave-length of a band the long wave-length edge of the band in one spectrum is brought into coincidence with the corre- sponding short wave-length edge in the other. The mode of calibration of the instrument to read directly in wave-lengths is described and the application of the instrument to the quantitative estimation of pigments by wave-length measurements of their absorption bands detailed.The method depends on the principle that if two pigments are present together in solution and their respective absorption bands have different mean wave-lengths then the mean wave-lengths of the resultant absorption bands will vary with the relative concentrations of the pigments pro- vided the band of one pigment is approximately similar to a band of the other and if a t no concentration do the bands appear separate. An illustration of the application of the method is given in the case of the estimation of the percentage saturation of blood with carbon monoxide. The accuracy of measurement attainable was found to be about 0-6 8.Various sources of error are discussed. J. S. G. T. Absorption of Light by Chlorine. H. VON H-AN and K. SIEDENTOPF (2. Elektrochem. 1922,28,496-499).-A preliminary account is given of measurements of the absorption spectrum of chlorine for a large number of wave-lengths between 254 pp and 643 pp making use of the very sensitive method of measurement recently described by the authors (A. 1922 ii 332). The results show that nowhere is chlorine entirely transparent but that in all regions absorption occurs which is generally very difficult to measure. The measurements are reproducible although the absorption in some cases does not amount to more than 0.2-0-3%. J. F. S.ii. 106 ABSTRACTS OF CHEMICAL PAPERS. The Quantitative Absorption of Light by Simple Inorganic Substances.11. The Chlorides of Arsenic Antimony and Bismuth. ALEXANDER KILLEN MACBETH and NORAH IRENE MAXWELL (T. 1923 123 370-375). The Absorption Spectra of Thallim and Indium Vapours. WALTER GROTRUN (Z. Physik 1923 12 218-231).-According to the Bohr atomic theory emission lines can occur only as absorp- tion lines a t any temperature when the initial stage in the absorp- tion corresponds with a molecular or atomic state which is of frequent occurrence in the molecules of the gas. Absorption spectra are thus useful in throwing light on the variation in the quantum condition of gas molecules with temperature. Series schemes of the emission spectra given for aluminium gallium indium and thallium show that for these metals not the s but the p-terms are the greatest of all the known terms.For thallium a t a temperature of 400° two absorption lines of the 2p2 subordinate series X=3775-72 and h=2767.87 first make their appearance and a t 500-608" other lines in this series appear. With increasing temperature these lines broaden probably owing to molecular (Tl,) adsorption. At 800° the 2p subordinate series is first observed the order of appearance being X=5350-46 and then the doublet X=3529 and X=3519-24. The indium absorption spectrum behaves similarly with rise in temperature. The differ- ences between the temperatures a t which the respective lines of the 2p and the 2p1 series are first observed increase as the series aluminium to thallium is ascended for indium the temperature difference is 100-150" and for thallium about 400". An indium adsorption line is observed a t X=2836.90 which is not included in the series schemes.From these absorption experiments it is clear that the outermost electron in the aluminium series of elements follows an azimuthal two quantum orbit. The Ultra-violet Absorption Spectra of Aniline and the Toluidines. F. W. KLINGSTEDT (Compt. rend 1923 176 248-250).-Aniline in solution in hexane shows nine narrow bands between X=2991 and 2704 and a broad band at X=2340. The narrow bands are almost equidistant from one another. With respect to benzene the absorption bands of aniline are displaced towards the red and the intensity of absorption is about eight times greater. The absorption spectrum of aniline in solution in water alcohol or carbon tetrachloride is very different from the normal spectrum.In these solvents the narrow bands are fused into one broad band. The absorption spectra of 0- and p-toluidines are very different. The ortho has two broad bands whilst the para has seven narrow bands and a broad band in the extreme ultra-violet. W. E. G. W. G. The Absorption in the Ultra-violet of a Series of Deriv- atives of Camphor. A. HALLER and R. LUCAS (Cornpi. rend. 1923 176 45-49).-A study of the absorption spectra in the ultra-viole t of the benz ylidene - anisylidene- piperonylidene -,GEXERAL AND PHYSICAL CHEMLSTRY. ii. 107 m-hydroxybenzylidene- m-methoxybenzylidene- p-tolylidene and m-tolylidene-derivatives of camphor shows that all these com- pounds present a strong absorption band the maxima of which vary with each compound. On the other hand benzylcamphor and anisylcamphor do not give this absorption band.The curves for m-hydroxylbenzylidenecamphor and for m-methoxybenzylidene camphor are practically identical. The maximum of absorption in the compounds named above is displaced further towards the red as the substituent group is of greater weight. W. G. The Ultra-violet Absorption Spectra of some Alkaloids of the isoQuinoline Group. Narcotine Hydrastine and Hydrocotarnine. PIERRE STEINER (Cornpi. rend. 1923 176 244-246).-The results obtained indicate that the ultra-violet absorption spectrum of narcotine is determined by the benzene nucleus of its molecule ; the isoquinoline nucleus only displaces the absorption towards the red.For papaverine (cf. this vol. ii 2) on the other hand it is the isoquinoline nucleus and not the benzene nucleus which is the determining factor. The spectrum of hydrastine only differs from that of narcotine by a displacement of its maxima and minima towards the shorter wave-lengths and by small differences in the intensity of absorption. Hydro- cotarnine which contains a partly saturated isoquinoline nucleus has a spectrum formed of a single band in the ultra-violet. Accord- ing to the results tabulated it should be possible to estimate sp&trographically 0.07 mg. of narcotine or hjkirastine in 2 C.C. of solvent. W. G Absorption Spectra of Pyrrole and its Derivatives. 11. The Influence of Methyl Groups on the Absorption Spectra of Pyrrole and its Derivatives.G. KORSCHTJN and (Mim) C. ROLL (Bull. SOC. chim. 1923 [iv] 33 55-67).-The absorption spectra of the ethyl esters of the following pyrrolecarboxylic acids were examined 2 5-dimethyl- 2 3 5-trimethyl- 1 2 5-tri- methyl- and 1 2 3 5-tetramethyl-pyrrole-4-carboxylic acids 2 &dimethyl- and 2 3 5-trimethyl-l-aminopyrrole-4-carboxylic acids 2 Ei-dimethyl- and 1 2 5-trimethyl-pyrrole-3 4-dicarb- oxylic acids and 2 5-dimethyl- and 2 3 5-trimethyl-l-carb- amidopyrrole-4-monocarboxylic acids and also that of 1 2 5- trimethyl-pyrrole. The general conclusions drawn are that the introduction of a methyl group into position 1 (attached to nitrogen) causes a +placement of the absorption curve towards the ultra- violet. At the same time if the derivative has two absorption bands they are united into one band.On the contrary the intro- duction of methyl into position 3 causes a displacement of the curve towards the red and at the same time the first band is lowered and the second raised. The methyl groups in position8 2 and 5 in 1 2 5-trimethylpyrrole displace the curve towards the red. Three methyl groups introduced into pyrrole in positions 1 2 5 only increase very slightly the intensity of the absorption bands. G. F. M.ii. 108 ABSTRACTS OF CHEMICAL PAPERS. Colour and Chemical Constitution. XVI. Further Miscellaneous Observations. JAMES Mom (Trans. Roy. Soc. 8. Africa 1922,1OY233-237).-1n this paper are given the absorp- tion wave-lengths of all the “ monocyclic ” and ‘‘ dicyclic ” dyes which were used in establishing the author’s theory of the colour of “ cyclic ” coloured substances (cf.A. 1921 ii 6 ; 1922 ii 333). 2 4’-Dihydroxybenzhydrol has X 543 in alkali X 486 in hydro- chloric acid and A 495 in water suspension. The 4 4’-isomeride has A 539 in dilute alkali but in acid is the same as the 2 4/-COm- pound. 2-Hydroxy-4’-dimethylaminobenzhydrol has h 561 (broad) in alkali h 500 in acid; the 4 4’-compound has X 572 in alkali and X 504 in acid. 2 4 4’-Trihydroxybenzhydrol has A 494 instead of the expected X 550. 2 4-Dihydroxy-4‘-methoxybenz- hydrol has X 380 in alkali and appears to be monocyclic; 2 4- dihydroxy-3’ 4’-dimethoxybenzhydrol-2’-carboxylic acid is also monocyclic with X 390 in alkali and so is mono-a-naphtholphthalein from phthalaldehydic acid and a-naphthol with X 370.The C- phenyl derivative of the last-named has X 401 in alkali but X 543 in strong sulphuric acid. The hydrol from p-hydroxybenzaldehyde and a-naphthol is violet with A 590 whilst that from p-naphthol is pink h 556 in alkali. Phenol-(3-naphtholphthalein has A 570. The following show differences in sodium hydroxide (1) and sodium hydrogen carbonate (2) respectively 3- hydroxyphenolphthalein X 556 (1) and X 562 (2) ; 3 6-dihydroxyphenolphthalein X 549 (1) and X 563 (2) ; 4 5-dihydroxyphenolphthalein X 558 (1) and X 568 (2). 5-Methoxyphenolphthalein has A 565 whilst the 3 6- 4 5- and 5 6-dimethoxyphenolphthaleins have X 568 h 556 and A 571 respectively. Other phenolphthalein derivatives ex- amined were 3-nitro- X 570 ; a-nitro-fgjE-tetrabromo- h 597 {cf.this vol. ii 48 for nomenclature) ; Ei-nitro- X 572 ; ahcd-tetra- chloro- X 581. Phenoldimethyl- a-naphthylaminephthalein is green X 625. The following derivatives of Ghosh’s quinolinic acid were examined phenolquinolinein X 533 ; o-cresolquinolinein X 544 ; thymolquinolinein X 593 ; resorcinquinolinein X 490 ; orcin- quinolinein X 496. In the triphenylcarbinol series the following are given o-hydroxy- malachite-green X 627 neutral X 572 in alkali X 505 in acid ; 2’-hydr- oxy-4-dimethylaminofuchsone h 490 neutral X 533 in alkali X 479 in acid ; p-methoxymalachite-green X 605 ; p-methoxybenzaurine X 551 ; p-nitromalachite-green X 642 ; p-aminomalachite-green X 581 in acetic acid. Values are also given for a considerable number of unclassified coloured substances.E. H. R. Cells with a Fluorescent Liquid. A. GRUMBACH (Compt. rend. 1923 176 88-90).-Goldmann (Ann. Physik 1908 27 449) has shown that when one of two electrodes plunged into a fluorescent liquid is illuminated an E.M.F. is set up and the illuminated electrode is positive. This was shown for saturated alcoholic solutions. It is now shown working with dilute aqueous golutions that the same effect may be obtained by keeping theGENERAL AND PHYSICAL CHEMISTRY. ii. 109 cell in the dark throughout and introducing into it near to one of the electrodes 1 C.C. of the same solution which has been intensely illuminated by a mercury arc for two hours. In this case the electrode near to which the liquid is introduced is a t h t negative.The E.M.P. a t first increases to a maximum and then decreases and finally changes its sign. With direct illumination of the electrode it is found that the E.M.P. continues to increase for some time after the source of light has been removed. Observations on the Phototropy of Inorganic Systems. J O S ~ RODR~GUEZ MOURELO (Anal. Pis. Quim. 1922 20 601- 605; cf. A. 1922 ii 604).-Further observations on the photo- tropy of sulphides of barium strontium and calcium. W. G. G. W. R. The Influence of Light on Zinc Sulphide. P. LENARD (Ann. Phyaik 1923 [iv] 68 553-573).-The cause of the darken- ing of zinc sulphide phosphors has beer traced to the polymerised sulphide molecules which are effective in phosphorescence. The darkening occurs however in zinc sulphide which is not phos- phorescent and it appears that the phenomenon has no direct relationship to the phosphorescence.The wave-lengths of the light producing darkening do not correspond with those effective in exciting phosphorescence. Water is necessary and ozone hydrogen peroxide chlorine etc. destroy the effect. On the other hand ammonia or reducing agents like formaldehyde reactivate a phosphor which has lost its sensitivity to light. The alkaline earth and magnesium phosphors do not bladcen. W. E. G. Influence of Adsorption of Ions 03 the Photochemical Sensitiveness of Silver Bromide. K. FAJANS and W. &ANKEN- BURGER (2. Elektrochem. 1922 28 499-505).-The authors have investigated the dependence of the sensitiveness of silver bromide on the method of precipitation.It is a known fact that silver bromide precipitated in the presence of an excess of silver nitrate is much more sensitive than that precipitated in the presence of an alkali halide. It is shown that under the influence of light the primary process taking place in silver bromide consists in the transference of an electron from a bromine-ion to a silver-ion with the formation of neutral atoms of bromine and silver. The work necessary to effect this change is dependent on the forces exerted on this electron in its initial and final states. In the presence of silver-ions from silver nitrate these forces are smaller and conse- quently the work required to effect the change is smaller and the sensitiveness of the silver bromide is increased. The Gamma Rays of the Family of Radium and of Thorium Studied by their Photoelectric Effect.M. DE BROGLIE and J. CABRERA (Compt. rend. 1923,176 295-296; Anal. Pis. Quim. 1922 20 467472).-By means of the apparatus previously described (A. 1922 ii 330) results have been obtained which are in accord with those of Ellis (A. 1921 ii 422; 1922 ii 466) and Meitner (A 1922 ii 416). 6" J. F. S. W. G.ii. 110 ABSTRACTS OF CHEWCAL PAPEBS. Rontgen Spectra and the Periodic System of the Elements. N. BOHR and D. COSTER (2. Physik 1923 12 342-374).-Th paper which forms a continuation of the Bohr theory of atomic structure (A. 1922 ii 363) and papers by Coster (A. 1922 ii 491 677) examines the relationship between the Rontgen spectra and the periodicity of the chemical properties and the optical spectra of the elements.It is shown that the movements of the inner electrons are subject to the same laws which operate in the case of the valency electrons. A table of the number of electrons in the various sub-groups of orbits is given for a large number of elements. This table which is based on spectroscopic data illustrates the building up of the electronic orbits with rising atomic number. The appear- ance of a new type of orbit is accompanied by a marked change in the chemical properties and the optical spectra of the elements. A new classification is proposed for the Rontgen spectra in which the principal groups are divided into sub-groups which are desig- nated by Roman numerals and to each level is given a value for n and k of the form n(kl,k2) [for example 2(2,2)L III].As in the work of Coster (Zoc. cit.) an arrangement of the Rontgen spectra is put forward which is based on a relationship between the fre- quency Y of each line and the difference between two spectral terms T' and T". In agreement with the principles of the quantum theory of line spectra these spectral terms multiplied by h give the energy required to transfer the electron from its normal orbit. The values T/B and d T 3 (where €2 is the Rydberg constant) are derived and tabulated for the K L N N 0 and P spectra and where the experimental data are missing the Rontgen spectra are interpolated from known values. Since the spectra are slightly affected by the form in which the element is excited a little uncer- tainty is introduced into the values of some of the elements with low atomic numbers; also the fine structure of some of the lines is a source of error.dFp is plotted against the atomic number for all the Rontgen spectra available and characteristic breaks are seen to occur in the curves for the L &I N and 0 spectra. The principal changes of slope occur in the neighbourhood of the platinum the rare earth and the iron groups. These irregularities are found a t those atomic numbers where it is predicted that a new sub-group of electrons makes its appearance. The appearance of electrons in the 4 orbit a t the element cerium the commence- ment of the rare earth group produces a sudden alteration in the slope of the dqB curve. At this point two of the lines in the M and N series separate into doublets. The binding energy of the 4 orbit a t atomic number 58 (cerium) is about &he same as that of the 6-quantum orbit and much less than that of the 5 and the 5* orbits.The energy of the 44 orbit increases as the atomic number rises until after the rare earth family of elements it exceeds the energy of the 5-quantum orbits. 'I'his behaviour is of undoubted importance for the study of the chemical properties of the rare earth group. The changes in energy of the electronic orbifs is more gradual at the end than a t the beginning of thisGENERAL IWD PHYSICAL CHEMISTRY. ii. 111 group. The value of dm for the 0 levels (5 quantum) changes very slightly between atomic numbers 58 and 72. This point is of greaf theoretical interest. The effective values of N and n for the 0 levels probably remain constant throughout the rare earth group.The constancy of N and n may also explain the similarity of the chemical properties and optical spectra of homologous elements in spite of considerable changes in the principal quantum number of the outer electronic orbit. The lack of periodicity in the K and L series is accounted for by the suggestion that the effective values of N and n for these orbits differ only slightly from the atomic number and the principal quantum number. Two types of doublets occur in the Rontgen spectra. The curves for one type run parallel throughout the whole of their course whereas for the other type they rapidly approach one another with decreasing atomic number. Although there is no evidence of periodicity in the Rontgen spectra in the same sense as it occurs in the optical properties it is expected that relationships will be obtained which will give a measure of the periodic behaviour of the elements.Uranium-2 and its Parent Substance. OTTO HAHN (2. physikal. Chem. 1923 103 461480).-A method is described for the determination of the relation of the activity of uranium-2 to that of uranium-X; the method has been applied to a large number of uranium-X preparations of different ages and a satis- factory constant value for the relationship obtained. The con- stancy of the value allows the conclusion to be drawn that uranium-Xl is the parent substance of uranium-2. Uranium-X1 therefore undergoes a dual P-ray disintegration of a kind which has hitherto not been observed with radioactive elements.A new method for detecting uranium-2 is de- scribed. From the activity ratio uranium-2 99.65%/\o-35% uranium-X it is shown that the branching P\\uz relationship is about 0.35%. In the calculation of this figure the absorption of the [3-radiation of uranium-2 with reference to that of uranium-X and uranium-X is taken into account. The disintegration scheme of the earlier members of the uranium series is therefore most probably represented by the annexed scheme. J. F. S. Ionisation by Collision of Hydrogen Nitrogen and Argon. T. L. R. AYRES (Phil. Mug. 1923 [vi] 45 353-368).-The ionis- ation of hydrogen nitrogen and argon molecules on collision with electrons has been measured for comparatively small values of the ratio of electric force X to the gas pressure p .The range examined is from X/p=l to X/p=600 and over part of this range Townsend and Bailey (cf. A. 1922 ii 836) have recently measured the velocity in the direction of the electric force and the mean velocity of agitation of the electrons in these gases. Ionisation by the electrons occurred for values of X / p as low as 2 in argon 5 in hydrogen and 10 in nitrogen. The effect of positive 5*-2 W. E. G. UI bX uxz<i B / \/ 711ii. 112 ABSTRACTS OF CHEMICAL PAPERS. ions was observed down to X/p=lO for argon 30 for hydrogen and 100 for nitrogen. No evidence was obtained for any appreciable variation in the ionisation due to slight contamination of the hydrogen and nitrogen but small amounts of impurities in the argon caused a marked diminution of the ionisation and increased the sparking potential.The ionisation with both positive and negative ions is in general agreement with that found by Townsend and Hurst for hydrogen and nitrogen (cf. A. 1906 ii 262). For argon however a t low values of X/p the ionisation is greater than found by earlier investigators. The nature of the metal used as electrodes is without appreciable effect on the ionisation. W. E. G. Thermal Ionisation of Gaseous Elements at High Tem- peratures. ARTHUR A. NOYES and H. A. WILSON ( J . Arner. Chem. Soc. 1922 44 280&2815).-A theoretical paper in which the thermodynamic equation used by Saha (A. 1920 ii 659) for calculating the thermal ionisation of the neutral atoms of gaseous elements into positive ions and electrons from their ionisation potentials is discussed with reference to the assumptions involved in the calculation.It is shown that the recent measurements of H. A. Wilson (A. 1916 ii 72) as well as the earlier experiments of Arrhenius (A. 1891 5 575) on the electrical conductivity of flames into which salt solutions are sprayed clearly indicate that the conduction arises from an ionisation process of the type under consideration and that they make possible a computation of the relative magnitudes of the ionisation constants. It is also shown that the relative ionisation constants of the five alkali elements calculated on the one hand from the conductivity of flames and on the other from the ionisation potentials by the thermo- dynamic equation form two series of values which run closely parallel to each other. Thus although in passing from lithium to cssium the ionisation constant increases 5700 times the ratio of the constants derived by the two methods for any one element does not differ from the mean value of that ratio for all five elements by more than 40%.The absolute values of the ionisation constants are derived from the flame conductivities with the aid of previous rough determinations of the mobility of the electrons and of the number of them per C.C. in similar flames. Although this could only furnish an estimate of the order of magnitude of the constants yet they were found to correspond well with the values calculated by the thermodynamic equation the latter being only 1.1 to 2.3 times as large.The Ionisation of Mercury Vapour in Presence of Argon. GEOROES D~JARDIN (Compt. rend. 1922 175 1203-1206 ; cf. this vol. ii 47).-Experiments were made with mercury vapour in presence of argon in order to ascertain whether the effect of the gas is similar to that of helium. The results show that ionisation resulting from impacts on mercury atoms of electrons the speed of which is greater than the critical ionisation speed (corresponding with 10.4 volts) is inappreciable and only becomes evident a t a J. F. S.GENERAL AND PHYSICAL CHEMISTRY. ii. 113 speed corresponding with 11-3 volts. On increasing the potential a sudden increase in the current is observed when the spatial charge of the electrons is completely neutralised and simultaneously a glow appears in the neighbourhood of the electrodes.The corre- sponding potential (the " illumination potential ") depends on the shape of the electrodes and on the pressure. Ionisation of the argon by direct impact begins a t a potential of about 15 volts. Between 11-3 volts and the illumination potential the intense lines of the mercury arc spectrum are obtained; above this limit the whole mercury arc spectrum and the red spectrum of argon are visible the latter increasing in intensity above 15 volts. Above 35 volts lines in the blue spectrum of argon are observed. The author infers from his results that for electrons traversing an atmosphere of argon there exists a first critical velocity of about 11.3 volts and that a resonance radiation emitted by the gas under these conditions ionises mercury vapour.This ionisation is not accompanied by any notable modification of the mercury spectrum analogous to that produced in presence of helium. Argon appears to exert only a feeble selective action on the second spectrum of hydrogen (Merton and Barratt A. 1922 ii 461) and on the cadmium spectrum (Collie and Watson A. 1918 ii 383). It is possible that the special influence of helium is due to the greater quantum of the radiations which it emits. H. J. E. Ionisation Produced by the Hydration of Quinine Sulphate. (M~LE) CHAMI~ (Cornpt. rend. 1923 176 251-253).-When the hydration is carried out in an ionisation chamber and the curve of increase in weight is compared with the curve of the diminution in current it is found that the duration of the phenomenon is the same for the two curves and depends on the density of the layer of the salt.Any effect which modifies the one curve modifies the other in the same manner. The weight of water of hydration as well as the maximum intensity of the current of ionisation and the quantity of electricity liberated during the hydration appear to be proportional to the weight of quinine sulphate used. W. G. Conduction Process in Ordinary Soda-Lime Glass. CHARLES A. KRAUS and EDWARD H. DARBY ( J . Amer. Chem. SOC. 1922 44 2783-2797) .-The replacement of sodium-ions in soda- lime glasses by ions of other metals has been investigated. It is shown that although the sodium-ions may be replaced by the ions of many other metals from their amalgams as well as from their fused salts under a potential gradient replacement occurs more readily from the fused salts than from the amalgams.In most instances the glass formed on replacement is not stable. In some cases the glass is completely disintegrated and in others it cracks on cooling. Sodium may be replaced by silver to a depth of about 0.1 mm. without cracking the glass. On replacing sodium by silver under the action of a potential a sharp boundary is formed between the sodium and the silver ions. From the rate of motion of the boundary the speed of the ions under a unit potential gradientii. 114 ABSTRACTS OF CHEMICAL PAPERS. has been determined; the following vahes are recorded 278" 4.52 x 10-8 ; 295* 1.46 X lo-' ; 323" 3.26 x lo-' and 343" 5.9 x cm./sec. The increased velocity of the ions with increased tem- perature corresponds with the increased conductivity of the glass with increased temperature.The fraction of the total sodium present in the glass which takes part in the electrical conduction has been calculated from the depth of penetration of the boundary and from the amount of electricity passing as well as from the change in weight of the tube. It is found that 74-82% of the total sodium present in an ordinary soda-lime glass takes part in the conduction. The remaining sodium is either not in a charged state or otherwise the ions are held in fixed positions. The fraction ionised as defined in this way increases slightly between 278" and 343". The following values of the percentage ionisation and the resistance in ohms are recorded 278" 74.4% 72800 ohms; 295" 76.8% 35000 ohms; 323" 79.4% 14200 and 343" Sl.O% 6600 ohms.5. F. S. Potential Difference between Glass and Electrolytes in Contact with Glass. WALTER S. HUGHES (J. Arner. Chem. Soc. 1922 44 2860-2867) .-The potential difference between glass and solutions of electrolytes has been investigated a t 25". It is shown that glass surface potentials are established and maintained by the passage of electricity through glass. The glass surface potential is a linear function of the hydrogen electrode only over a limited range of values. Variations in the glass surface potential may be used as the basis of an electrometric titration method in the presence of oxidising agents which render the hydrogen elec- trode useless for such purposes.In such cases the method might yield data which could not be obtained in any other way. The presence of certain substances other than hydrogen-ions such as concentrated solutions of salts or gelatin affects glass surface potentials . J. I?. S. Significance of the Electrode Potential. JAROSLAV HEY- ROVSKI? (Proc. Roy. Soc. 1923 [ A ] 102 628-640).-Evidence is adduced that the process by which a metallic electrode immersed in an aqueous solution becomes charged is represented by M+OH' + MOH+ 0. By the application of the electronic con- ception of chemical combination to a reversible thermodynamic cycle a formula is obtained for the electrode potential in terms of the ionisation potential and basigenity of the metal. The basicity of metallic oxides is discussed by means of Beketoff s principle (A.1889 332) and it is concluded that a metallic hydroxide .is the more basic the more negative the electrode potential and the greater the equivalent weight of the metal The mechanisms of galvanic and concentration celh the phenomena of electrodeposition and overvoltage and electrode processes in non-aqueous solvents are discussed in the light of the theory developed. " Absolute zero potential " values of contact E.M.F. derived from electrocapillary phenomena are shown to be illusory,GEN-ERAL AND PHYSICAL CHEMISTRY. ii. 115 and the probable potential a t which reversal of the sign of the charges in the double layer occurs is indicated. Determination of Absolute Single Electrode Potentials. ALLEN GARRISON ( J . Amer.Chern. Soc. 1923 45 374).-The methods hitherto employed for determining absolute single electrode potential differences have been enumerated and briefly discussed and a new method of effecting this determination is described. The method is based on the assumptions (1) that the mechanical force on a substance suspended in an electrolyte through which an electric force acts is due t o the charge on the suspended system (2) that the direction of the force is determined by the sign of the charge and (3) that there is no charge or potential difference relative to the electrolyte when in an electric field there is no mechanical force relative to the electrolyte. The method used consists in suspending a light metal needle shaped like the needle of a quadrant electrometer by a phosphor-bronze ribbon in an electrolyte con- taining such a concentration of the metal-ion that there is no electric double layer at their interface.This isoelectric condition is indicated by the absence of any mechanical forces when an electric field is applied through the electrolyte. The potential of the needle is at the same time compared with the potential of a standard half cell. On eliminating the liquid junction potential the measured E.M.F. is the absolute potential of the constant eleotrode. A full description of the apparatus and its method of use is given in the paper. Using a silver needle a t itas isoelectric point as the zero electrode the absolute potential of a 0-1N-calomel electrode is found to be between -0.20 volt and -0010 volt a t 25’.This result is a confirmation of Billitzer’s value of -0.13 volt and it removes the objections which have been made to the method employed by Billitzer (2. Elektrochem. 1902 8 635). J. E. VERSCHAFFELT (Rec. traa. chim. 1922 41 7-777; cf. Aten A. 1916 ii 370).-A mathematical argument in which the aixthor develops views previously put forward (Bull. Acad. roy. Belg. 1919 441). The conclusion is drawn that the variation of potential due to the application of E.M.F. is mainly effective at the cathode in the case of two electrodes of a metal in contact with a solution of one of its own salts whilst with the same salt but with electrodes of a more electropositive metal the anode potential undergoes the greater variation and thus only the anode is polarised. Activity Coefficient of Hydrochloric Acid in Aqueous Salt Solutions.HERBERT S. HARNED and NORMAN J. BRUMBAUQH ( J . Amer. Chem. Soc. 1922 44 2729-2748).-E.M.F. measuret ments of cells of the followin types have been carried out a t the kmperatures indicated HfMCl (c) in 0*1N HClIEgCl/Hg at ISo 25” and 30° where M denotes barium strontium or calcium; H,1MC12 in 0*1N HCIIKCl (sat.)lHgCIIHg a t 25O where M signifia the same metal as before; H2JKC1 (c) in HCl (c’)lAgCl(Ag and HJKC1 (c) in HC1 (c’)]HgClJHg where c’ is 0-01N and 0.001N at J. S. G. T. J. F. S. The Polarisation of Electrodes. H. J. E.ii. 116 ABSTRACTS OF CHEMICAL PAPERS. 18” 25” and 30”. From the data obtained the decrease of free energy and the decrease of the heat content of the cell reaction have been calculated as well as the changes in partial molecular free energy and heat content of hydrochloric acid in the mixtures.The mean activity coefficients of hydrochloric acid in solutions of potassium sodium lithium barium calcium and strontium chlorides have also been calculated. By means of the formula log Fa’= a’cl-P’pm’+d’ (p-cJ the values of the mean activity coefficients (Fa’) of hydrochloric acid in the acid salt mixtures containing acid a t concentrations from 0.001N to N may be calculated with considerable accuracy. In solutions of greater dilution of acid it is necessary to add a term to the above equation which is a function of the salt to acid concentration ratio thus log Fa’= a ’ ~ ~ - ~ ~ p ~ ’ + c c ’ ’ ( u - - ~ ~ ) + y ’ [ ( p - ~ ~ ) / c ~ ] is approximately valid for solutions containing acid of concentration as low as 0-001N.Thus when (p-c1)/cl is very high a considerable increase in the value of Fa‘ is observed. In the above equations c1 is the concentration of acid a’ P’ a” m’ are constants and p is the ionic strength and for uni-univalent electrolytes equals the sum of the concentrations of the salt and acid or (c+cl). It is pointed out that the effect mentioned above is probably due to an increase in activity of the hydrogen-ion. If as is to be expected the same phenomenon is observed in mixtures containing other ions it will be of considerable importance especially in dealing with the problem of the solubility of sparingly soluble salts in solutions of other salts. Evidence has been obtained which leads to the conclusion that in solutions of strong bivalent chlorides a t the same temperature and con- centration the chloride-ion will have the same activity and also that the activity of the chloride-ion in uni-univalent chloride solu- tions is greater than in bivalent chloride solutions of the same ionic strength.J. F. S. Activities of the Ions of Potassium Hydroxide in Aqueous Solution. M. KNOBEL ( J . Arner. Chem. Xoc. 1923 45 70- 76).-The author has determined the E.M.F. of cells of the type H,IKOH (c,)lKHg,lKHg,]KOH (c,)]H at 25” for concentrations of potassium hydroxide ranging from 3N to 0-0001N. The activity coefficients of the ions of the solution at various concentrations and the free energy of dilution between various concentrations have been calculated and tabulated. The data given by Chow (A.1920 ii 281) are found to be incorrect; differences of 2-8y0 are found between Chow’s values and the present values. The relationship between the activity and concentration for potassium hydroxide has been found to be similar to that for other uni- univalent electrolytes. J. F. S. Degree of Ionisation of Ethyl Alcohol. I. From Measure- ments of Conductivity. PHILIP s. DANNER and JOEL H. HILDE- *BRAND (J. Amer. Chem. Soc. 1922 44 2824-2831).-The methods available for the purification of ethyl alcohol are discussed as to their efficiency and the following method has been adopted for the preparation of absolutely pure material. Commercial 95% alcoholGENERAL AND PHYSICAL CHEMISTRY. ii. 117 was distilled with 5 C.C.of concentrated sulphuric acid and 20 C.C. of water per litre and the distillate boiled for several hours with 10 g. of silver nitrate and 1 g. of potassium hydroxide per litre. This product was distilled on to commercial quicklime 600-700 g. per litre and boiled for eight hours. The mixture was then shaken vigorously for twenty-four to thirty-six hours at the ordinary temperature and distilled on to specially prepared quicklime made by burning the mixture of calcium hydroxide and carbonate such as is obtained by drying slaked lime in the air. This product was present in the quantity 100-150 g. per litre of alcohol and the mixture was boiled for four to six hours. The alcohol was then distilled into the vessel from which the final purification was to be made and at this stage had a specific conductivity 1.0 x 10-7 ohms-1.Subsequent distillation in evacuated sealed apparatus gave a value 2.2 x 10-8 ohms-1 but here the most volatile portion was not removed. Repeated vacuum distillation with removal of the most volatile portion gave a steadily decreasing value with each repetition until the tenth distillation gave the value 1.35 x 10-9 ohms+ and this is regarded as the value for the purest ethyl alcohol. The dissociation constant calculated from this figure is 2.89 x 10-l6 for the ionisation C,H,*OH iZ C,H,O’+H’ ; the mole- cular fraction ionised is 1.0 x which i s comparable with the similar value for water 1.8 x Degree of Ionisation of Ethyl Alcohol. 11. From Measure- ments of Electromotive Force. PHILIP s. DANNER ( J .Amer. Chem. Soc. 1922 44 2832-2841 ; cf. preceding abstract).-The E.M.F. of a series of cells of the types H2PtIHC1,HgC11Hg HglHgC1,NaCllNa (2-phase amalgam) and Na (2-phase amalgam)] C2H,*ONaIPtH2 all in pure ethyl alcohol (Zoc. cit.) have been measured a t 25”. The cells were very slow in reaching an equi- librium value but were reproducible to 0-0001 volt and calculations based on the values obtained involve no assumptions as to the value of the potential a t the boundary water/alcohol since this is not present. The dissociation constant for the ionisation C,H,*OH C,H,O’+H’ is calculated to 7.28 x and the molecular fraction dissociated to 1.6 x This indicates that ethyl alcohol is dissociated only to 1/100 of the amount to which water is dissociated.The discrepancy between the present results and those given in the previous paper (Zoc. cit.) is attributed to the assumptions involved in the interpretation of the conductivity measurements since the maximum possible error of the E.M.F. measurements 0.002 volt would not produce a greater error than 10% in the value of the dissociation constant. The Ionisation of Water in Solutions of Electrolytes. E. DOUMER (BUZZ. Soc. chim. 1923 [iv] 33 49-55).-Hittorf’s assumption that water is only ionised in negligible proportions in solutions of electrolytes does not seem to be justified especially in the case of acid electrolytes and particularly of hydrochloric acid solutions. Evidence for the fact that the liberation of oxygen at the anode in the electrolysis of hydrochloric acid is a primary J.F. S. J. F. S.ii. 118 ABSTRACTS OF CHEMICAL PAPERS. effect and not a secondary reaction due to the action of nascent chlorine on water is furnished by electrolysis with a silver or mercury anode when the amount of oxygen liberated is actually greater than with platinum anodes whilst all the chlorine combines with the anode forming the metallic chloride. Initially the silver anode becomes covered with a brown film which eventually becomes white so that both chlorine and oxygen are apparently discharged simultaneously the former then displacing oxygen from the oxide when free metal is no longer available on the surface of the anode. Experiments on the electrolysis of dilute hydro- chloric acid showed that for 50 C.C. of hydrogen liberated at the cathode 16.55 C.C.of oxygen were formed at the anode and it is therefore concluded that of the total hydrogen-ions discharged 2 x 16-55/50 were derived from ionised water that is about 66%. This surprisingly high proportion finds confirmation in a deter- mination of the total loss of hydrochloric acid in the electrolyte compared with the theoretical loss had all the liberated hydrogen been derived from hydrogen chloride. Further the molecular conductivity of hydrochloric acid solutions is about three times as great as that of alkali chloride solutions and the explanation provided by the above hypothesis is that in such acid solutions there are in addition to hydrogen- and chlorine-ions about twice as many hydrogen- and hydroxyl-ions. G. F. M. Theory of the Polarisation of the Electrolytic Generation of Oxygen.11. Anodic Behaviour of Manganese in Solu- tions of Alkali Hydroxides. G. GRWE and H. METZGER (2. EZe&rochem. 1923 29 17-30; cf. ibid. 1922 28 568).-The anodic behaviour of pure manganese in solutions of sodium hydroxide has been investigated. It is shown that in hot concentrated solu- tions with small current densities manganese passes into solution in the bivalent condition with medium current densities (0.3- 0.1 amp. /dcm.2) in the tervalent condition and with higher current densities in the sexavalent condition. The solution of manganous oxide thus produced is yellowish-red in colour and that of the manganic oxide brownish-red. The sexavalent manganese forms manganate the production of which is always accompanied by the liberation of oxygen.At ordinary temperatures and also in dilute hydroxide solution manganese passes into solution in the septa- valent condition with liberation of oxygen. The potentials corre- sponding with the individual anode changes have been measured at various temperatures and concentrations of alkali. The polaris- ation of the electrolytic evolution of oxygen occurs because the manganese becomes covered with a thin film of dioxide which then forms permanganic acid according to the equation Mn0,+2H2O + 3 0 -+ MnO,/+H'. This substance then decomposes completely at lower current densities in N-sodium bydroxide with the evolution of oxygen according to the equation 2HMn0 + 2Mn0,+H20+ 3/20,; a t higher current densities only a portion decomposes in this way whilst the other portion diffuses into the solution and forms sodium permanganate.The competition of the velocityQENERAL AmD PRYSICAL CHEMISTRY. ii. 119 .of the two reactions the oxidation of manganese dioxide to per- matnganate and the spontaneous decomposition of the perman- ganic acid with liberation of oxygen determines the extent .to which the current is used for the liberation of oxygen and the formation of permanganafe and also the potential of the process. J. F. S. Effect of Fluorine on Electrolytic Oxidations. A. Rfos Y M I R ~ (Anal. Fb. Quim. 1922 20 644-661).-The electrolytic oxidation of chrome alum and potassium hydrogen phosphate is increased with increasing amounts of potassium fluoride. It is supposed that the fluoride-ions a t the moment of their discharge a t the anode react directly or indirectly by means of a peroxide of platinum with the electrolyte present.With water ozone is formed whilst in other cases per-compounds may be formed for example in the case of phosphates perphosphoric acid. The theoretical objections to this theory are discussed. Electrolysis with a Dropping Mercury Cathode. I. Deposition of Alkali and Alkaline-earth Metals. JAROSLAV HEYROVS~ (Phil. JIaq. 1923 [vi] 45 303-315).-The decom- position potentials of the alkali and alkaline-earth metals have been determined by means of a dropping mercury cathode. When the dropping electrode is made the cathode it is found that in neutral or alkaline solution hydrogen is not evolved even with high polaris- ations and hence this arrangement is convenient for the study of the cathodic deposition of the most positive metals which are otherwise attacked by water.The decomposition potentials found by this method were lithium -2.023 potassium -1.883 sodium -1.860 cEsium -1.837 rubidium -1.796 ammonium -1.787 calcium -2.023 magnesium -1.903 strontium -14362 and barium -1.814 volts. Assuming that the alkali metals form compounds with the mercury it is possible to calculate the a f i i t y of the metal for mercury this being given by the equation A= r,,-E.P. where T is the observed decomposition potential with the drop electrode and E.P. is the decomposition potential obtained by G. N. Lewis. The afhity for mercury increases with increasing atomic weight but sodium occupies an anomalous position behaving like a more noble metal.It is deduced that the E.P. of caesium is -3.3 volt. Transport Numbers of Potassium Hydroxide in Aqueous Solution. M. KNOBEL D. K. WORCESTER and I?. B. BRIGGS (J. Amer. Chem. Soc. 1923 45 77-79).-The E.M.F. of concen- tration cells of potassium hydroxide of the type H,IBOH(c,)l KOH(c,)]H have been measured a t 25" for concentrations between 3~0N and 0.01N. These values combined with those obtained for cells without transport (see this vol. ii 116) have been used to calculate the transport number of the potassium-ion in solutions of potassium hydroxide of various concentrations. The transport number of the potassium-ion is found to be constant and equal to 0-2633 over the whole range of concentration 3*0N to O-OlN and to increase with decrease in concentration below this value to G.W. R. W. E. G.ii. 120 ABSTRACTS OF CHENICAL PAPERS. 0.274 at infinite dilution. The following values of the B.3i.F. are recorded for the cells measured c1=3.0N c2=O.3N ~=0.03683&- 0.08003 ; cl= l-ON c,=O*lN ~=0*03104&0~00003 ; C1=0.3N C =O* lN E= 0.01424 &0.00003 ; c1 = 0.3N c2 = O.O3N 6 =0.029 16 & 0.00003 ; c,=O*lN ~,=0*01N ~=0~03465-+0~00015. J. F. S. Possibility of Varying Intermediate Stages in the Kobe Reaction and a Case of Anodic Ester Formation with Aromatic Acids. C. SCHALL (2. Elehrochem. 1922 28 506- 51 1) .-The electrolysis of molten lead acetate manganous acetate in benzoic acid and alkali benzoates in benzoic acetate has been investigated; it is shown that in the case of metals of constant valency the change takes place according to the equation xRCO,'+ xF=x/2R.R+xCO but when the metal has a variable valency the primary change is represented by the equation M(RCO,),+ xRC0,'f-xF=M(RCO,), and if the temperature is sufficiently high this reaction is followed by a secondary thermal action M(RC02),,=M(RC0,),+x/2R . R+xCO,. These equations indicate that intermediate compounds may be formed in the Kolbe reaction. When potassium benzoate containing benzoic acid is electrolysed using a silver anode phenyl benzoate is produced. This formation is due a t least in part to the oxidation of the acid to phenol by the silver oxide produced on the anode. The Anomalies of Strong Electrolytes with Special Refer- ence to the Theories of J.C. Ghosh. 11. HENRY J. s. SAND (Phil. Mag. 1923 Evil 45 281-292; cf. this vol. ii 55).-Alter- ations have been made in the subsidiary hypotheses of Ghosh to bring them into line with the equation p/poo=e-cflNRT where p / p M is the ratio of the molecular conductivities and G' the work required to separate one gram-mol. of ions. Although the theory is strengthened by these changes the number of subsidiary hypotheses is so great that the above equation must be regarded as an empirical formula. The hindrances to conduction in sl medium of uniform dielectric constant by the electric fields of the ions is of the nature of polarisation and the conductivity should be greater with rapidly alternating currents and high potential gradients than with small constant potential gradients.Since this conclusion is contrary to experiment the idea of a solvent with uniform dielectric constant has been abandoned. An explanation of ionisation is put forward based on the assump- tion that solvent molecules possess polar properties the ionising media consisting of a number of bipoles similar to those postulated by Debye in his explanation of the dielectric properties of the media. These bipoles which are capable of rotation are held when in the powerful electric field of the ion and their rotation stopped and converted into vibrational motion. Each ion will thus consist of the simple charged atom or group in the centre of a number of polar water molecules which is capable as a whole of rotatory or vibratory motion. The ions become bound when they meet other ions of different polarity and are then only capable of vibration around a position of equilibrium and become incapable of J.F. S.GENERAL AND PHYSICAL CHEMISTRY. ii. 121 transmitting a current. These views lead to a formula similar to that of Ghosh. The Ghosh equation whilst yielding satisfactory values for binary electrolytes breaks down for salts like barium chloride. The introduction of the Milner virial into Ghosh’s formulz! does not lead to any improvement. Faraday’s Law and the Action of the Electrical Discharge on Gases. A. DE HEMPTINNE (Bull. Amd. TOY. Belg. 1919 [v] 5 521-527).-Faraday’s law has been shown to hold with fair approximation for chemical effects produced by an electrical discharge on gases a t low pressures.Faraday’s Law and the Chemical Action of the Electrical Discharge. A. DE HEMPTINNE (Bull. Acad. roy. Belg. 1919 [v] 5 161-177).-An investigation of the reduction of unsaturated oils by hydrogen under the influence of an electrical discharge the amount of reduction being followed by the change in iodine number of the oil. A large number of experiments involving variations in thickness of dielectric density of current potential difference etc. are described and do not lend themselves to abbreviated description. The author concludes that Faraday ‘s Laws of Electrolysis are obeyed at any rate roughly. Faraday’s Law and the Action of the Electrical Discharge onMetallic Oxides. 11. 111. Tv. V. A. DE HEMPTINNE (Bull. A d . roy. BeZg. 1919 [v] 5 249-260; 1921 [v] 7 146-155 458468,590-595).-II.A study of the reduction of metallic oxides by hydrogen in presence of an electrical discharge. The results fall in Line with those previously obtained with unsaturated oils (cf. preceding abstract). Lead peroxide is taken as a standard substance for reduction and a large number of other metallic oxides and also chlorides and miscellaneous substances are compared with it. Carbon monoxide was found to be roughly as effective in reduction as hydrogen the experiments being carried out at low pressures to avoid polymerisation etc. of the monoxide. 111. The reduction of various substances by this method shows that as a rule it is unimportant whether the substance in question is in contact with the positive or with the negative electrode. Values are found for the ratio N/N’ where N is the number of hydrogen mole- cules disappearing during a reduction and N’ the number of ions and electrons (calculated from the measured current).This ratio has a value ranging from zero in the case of difficultly reduced oxides such as zinc or magnesium to above unity in the case of lead peroxide and manganese dioxide etc. the reducibility of an oxide being con- nected with the electrolytic potential of the corresponding metal. Potassium chlorate is almost unaffected under conditions sufficing for the reduction of most oxides a fact which is attributed to the purely electrical nature of the process no thermal effect being produced by the incidence of positive ions or electrons. Thus in the case of oxides the amount of reduction is approximately proportional to the amount of current passing.IV. The reduction of lead peroxide cupric oxide and ferroso- ferric oxide is effected in a dried atmosphere of hydrogen by W. E. G. E. E. T. E. E. T.ii. 122 ABSTRACTS OF CHEMICAL PAPERS. means of an electrical discharge the oxide in question being placed in contact with one of the electrodes. By measuring the variation of pressure of potential difference between the elec- trodes and the current flowing a relation is found between the number ( N ) of hydrogen molecules used in the reduction and the number of positive ions (Ni) and electrons (Nd). The point is raised as to whether in ionisation the hydrogen molecule loses one or two electrons. Activated hydrogen (H,) offers another explanation but the mechanism of the reduction remains in doubt.With lead peroxide in contact with the positive electrode N / N has values from 0 to 1.1 and when in contact with the negative electrode values of 2.7 to 1.4 for N/Ni are obtained. Similar results are obtained for other oxides. If the positive ions are formed by the loss of one electron from each hydrogen molecule and if each electron liberates one atom of oxygen which then combines with one molecule of hydrogen N/Ni and NIN should be equal to unity. Values (for these ratios) of 0.5 will correspond with the loss of two electrons when hydrogen is ionised and so on. V. In the earlier sections the loss of weight of oxides when sub- mitted to the action of an electrical discharge in presence of hydrogen was not determined.It is now found that in the reduction of lead peroxide the weight of hydrogen absorbed (as measured by the diminution in pressure) is equivalent to the loss in weight of oxide whether the latter is in contact with the positive or with the negative electrode. The oxide formed as a result of the reduction is probably lead suboxide. When nitrogen is substituted for hydrogen in these experiments no change is observed in either gas or solid except such as could be accounted for owing to defects in the apparatus. Carbon monoxide under similar conditions causes the lead peroxide to gain in weight probably owing to the formation of a deposit of a lower oxide of carbon. E. E. T. LOUIS BELL and P. R. BASSETT (Science 1922,56 512).-In the spectrum of the " negative tongue " which appears in the carbon arc at currents of at least 100 amperes there were found iifteen lines of which seven were coincident with the most conspicuous helium lines and two others with Ha and Hp.Some carbon nuclei are considered to dissociate into helium and possibly further although the hydrogen lines may be due to water vapour absorbed by the carbon. Dissociation of Carbon in the Intensive Arc. CHEMICAL ABSTRACTS. The Evolution of the Molecule of Ferric Hydroxide in Contact with Water. (MLLE) S. VEIL ( C m p t . rend. 1923 176 101-103) .-The molecular coefficient of magnetisation with reference t o iron content of the hydroxide and the oxide of iron depend to a large extent on the previous states through which the material has passed and the temperatures to which it has been heated.W. G. The Calculation of the Magneton Number of an Atom in Solution. J. H. SMITH (Phil. Mag. 1923 [vi] 45 375-3781.- The magnetic susceptibility of cobalt chloride in water is greaterr IGENERAL AND PHYSIC& CHEMISTRY. ii 123 than in alcoholic solutions and this change is associated with LI shift in the maximum of the light adsorption from O f i l O ~ to 0 . 6 5 ~ ~ Making the assumption that Wiedemann's law of the additivity of magnetic susceptibility holds for solutions the magneton number of the cobalt-ion in aqueous solution is found to be 24.6. The difference between the magnetic susceptibility in water and in alcoholic solutions may be ascribed either to a change in the diamagnetic or the paramagnetic part of the atom.A reason- able conclusion is that the frequency of the paramagnetic part of the atom is diminished. and this view is sumorted bv the decrease in the frequency oi the light absorbers in*the atom.". W. E. G. Paramagnetism and the Structure of the Atom. B. CUR- ( J . Phys. Rccdium 1922 3 443460).-The property of paramagnetism is confined very largely to the elements in column VIII of the Mendelkev classification and to the rare earths. The magnetic susceptibilities of the elements from chromium to copper following the order of the atomic numbers have been seriously studied and data are available to fix the magneton number (Weiss) of the metallic ions for many of the elements in their various stages of oxidation. For these elements the Weiss magneton number is seen to be given by a series of whole numbers which are inde- pendent of the degree of ionisation of the salt.A theoretical mterpretation of this regularity in the Weiss magneton number is sought in the structure of the atom and in particular in the N-level of electrons. This level is subdivided into N and N levels the latter first making its appearance with titanium. The number of electrons in the N level augments from Ti"" to Cu' for which element it attains a maximum value. It is assumed that the number of electrons in the M level remains constant a t 8 throughout. On plotting the magneton number of the ion against the number of electrons in the N level a symmetrical curve is obtained giving a maximum at Fe*** when the magneton number is 29 and N1 = 5.Ions containing an identical number of electrons in the N level give the same magneton numbers; thus Fe"' Mn" Mn"' and Cr" give the same values. The points corresponding with Co" and Ue" are somewhat displaced but these elements give a variable magneton number. At Ti"" and Cu' the magneton number is zero. The magnetic susceptibilities of the oxides of manganese and the oxides and sulphides of titanium and vanadium are in general agreement with the above curve. The metals offer con- siderable difficulties for the number of electrons which bind together the atoms is unknown. The work of Urbain and Janesch (cf. A. 1909 ii 116) has demonstrated the existence of two groups within the rare earths in each of which the magneton moment attains a maximum and then decreases.Qualitatively the changes in magneton number will be analogous to that of the group studied above. These results do not appear to be in accord with the modification of the M levels assumed by Bohr for this structure should lead to discontinuities in the curve of the magnetic moment.G. 124 ABSTRACTS OF CHEMICAL PAPERS. The results of Stern and Gerlach (2. Physilc 1922 9 353) are not in opposition t o the Weiss magneton. Influence of the Pitch of Sound on the Measurement of the Relationship k=cp/cv for Carbon Dioxide. BRUNO TORNAU (2. PhysiE 1923 12 48-57).-The ratio of the specific heats1 for carbon dioxide was found to be K,=1~3165&0*00032. Variation in the pitch of the sound produced no change in the value of KO. EDM. VAN AUBEL (BUZZ. Acad. roy.BeZg. 1921 [v] 7 155-159).-The validity of certain conclusions drawn by Michaud (A. 1920 ii 532) is discussed making use of existing data for the specific heats etc. of silicon boron rhombic sulphur thallium magnesium and chromium. Michaud's conclusions are shown to be untenable. Third Law of Thermodynamics. Evidence from the Specific Heats of Glycerol that the Entropy of a Glass exceeds that of a Crystal at the Absolute Zero. G. E. GIBSOX and W. I?. GIAUQUE (J. Amer. Chem. Xoc. 1923 45 93-103).- An improved calorimetric apparatus is described for determin- ations a t low temperatures. The specific heat of supercooled glycerol and the specific heat and heat of fusion of crystalline glycerol have been determined a t temperatures down to 6909°K. The specific heats of the glass and the crystals approach one another as the temperature is lowered and are almost identical below 140°K.The heat of fusion of glycerol a t the melting point 291.00"K is 47-50 cal./gram or 4370 cal./mol. and the entropy of fusion is 15.02 cal./degree per mol. or 1.073 cal./degree per gram. The entropy of supercooled liquid glycerol exceeds that of crystalline glycerol by 5-6-J=0.1 cal./degree per mol. a t 7OoK and it is concluded that this value will not be appreciably different at the absolute zero. J. F. S. E. D. EASTMAN (J. Amer. Chem. Soc. 1923 45 80-83).-The hypothesis that the expression for the mass effect in the entropy of all substances in which equipartition holds takes the same form as for monatomic gases is tested for all cases for which data are available.The results show that there is much evidence in support of the hypo- thesis and none definitely contradicting it. Several approximate equations are given for the calculation of the entropy of diatomic gases and metals. Physical and Chemical Transformations of Gibbs 's Systems. TH. DE DONDER (BUZZ. Acad. roy. BeZg. 1920 [v] 6,315- 328) .-A thermodynamical treatment of systems consisting of phases as defined by Gibbs. The author adopts a point of view very slightly different from the usual one. The Chemical Constants of the Halogens in the Monatomic and Diatomic Condition. 3'. A. HENGLEIN (2. Physilc 1923 12 245-252).-The chemical constants of chlorine bromine and W. E. G. W. E. G. Atomic Heat of Simple Substances. E. E. T. Mass Effect in the Entropy of Substances. J.F. S. E. E. T.GENERAL AND PHYSICAL CHEMISTRY. ii. 125 iodine have been calculated from the dissociation and vaporisation equilibria of these gases and the values are in good agreement with those derived by Stern and Tetrode. For the monatomic gases the following results were obtained for the chemical constants chlorine +0.72 bromine +1.26 iodine +1.56 and for the diatomic gases chlorine +O.OZ bromine +1-50 and for iodine f-2.55. Bromine and iodine have the highest chemical constant of any element. The heat capacity of solid bromine has been determined and a Debye function given for the calculation of its specific heat. The chemical constants of the halogens in the diatomic condition increase slightly as the temperature rises. W. E.G. Relation' between the Absolute Melting Boiling and Critical Temperatures of Substances. EDM. VAN AUBEL (Bull. A d . roy. BeZg. 1921 [v] ?,469-472).-The value of r a constant (according to Prudhomme A. 1920 ii 83 84 376; see also A. 1921 ii 622) deduced from the absolute melting and boiling points and critical temperatures of various substances has been calculated for a number of compounds using existing data and the following values of r have been obtained Mercury 0612 mercuric chloride 1-01 mercuric bromide 1.03 mercuric iodide 1.03 antimony tri- chloride 1.04 antimony tribromide 1.01 aluminium bromide 1-16 and aluminium iodide 1.10. All these substances. therefore. with the exception of mercury give a normal value (i:e. about hits) for r. E. E. T. Method for the Determination of the Melting Point of Difficultly Fusible Metals.MARCELLO PIRANI and HANS ALTERTHUM (2. Elektrochem. l923,2Sy5-8).-The melting point of metals with high melting point may be determined by using a hole (6 mm. deep and 1 mm. diam.) bored a t an angle to the axis of a 7 mm. square rod of the metal as a black body for temperature determination. That the metal had melted was indicated by drops of it falling from the hole. The heating was effected by passing a 50-period alternating current which could be varied by steps of 10 amp. to 1500 amp. through the bar. Using this method the melting point of tungsten and molybdenum has been determined and the values 3660"&60" and 2840"&40" respectively have been obtained. These values are in agreement with other recent deter- minations. J.3'. s. Separation of Lipid Mixtures by Combined Distillation and Atmolysis. Preparation of Practically Pure Ethyl Alcohol and Nitric Acid. ~ D O U A R D URBAIN and R$MY URBAIN (Compt. rend. 1923 176 166-168).-The apparatus consists of a distillation flask surmounted by a porous porcelain tube which is jacketed with a glass tube in which the pressure can be reduced. The porous tube is fitted with a condenser on top and is so arranged that the condensed vapours can be returned to the distillation flask or run into another vessel. With this apparatus it is possible to obtain 9943% alcohol by direct distillation. The water vapour passes through the wall of the porous tube and the condensedii. 126 ABSTRACTS OF CHEMICaL PAPERS.alcohol is returned to the distillation flask. In a similar manner it is possible by means of this apparatus to prepare 9906% nitric acid. The Heat of Oxidation of the Alkaline-earth Metals. A. GUNTZ and BENOIT (Compt. rend. 1923 176 219-220).-The authors have made measurements of the heats of solution of calcium strontium and barium respectively in dilute hydrochloric acid andfrom the results and the known heats of solution of their oxides in this acid have calculated the heats of oxidation of these metals to be 152.7 141.8 and 134.04 cal. respectively. I?. BOURION (Cmnpt. rend. 1923 176 95-98).-A theoretical dis- cussion in which it is shown that in order to observe in the pro- gressive neutralisation of an acid by a base differences between the values found and those calculated by proportionality by the current thermochemical methods the afkity constant of the acid must not be greater than 10-10 with the usual order of magnitude of the heats of ionisation. W.G. The Phenomenon of Molecular Association. ETTORE CARDOSO and GABRIELE BATTISTA (Anal. Pis. Quim. 1922 20 420432).-From a combination of van der Waals’s equation and the rule of Cailletet and Mathias the densities of a liquid and its vapour respectively dl and d3 are connected with the critical constants by the relation dld3/dC2= K(pT,/p,T) or more generally dld3/dc2 =f(pT,/p,T). Deviations of this function from a linear relationship are attributable to molecular association and are the more pronounced the greater is the difference between the degree of association of the coexisting phases.The liquid phase is in- variably more complex than the coexistent vapour phase. W. G. W. G. Berthelot’s Normal Acids and the Theory of Ions. G. W. R. Cohesion Pressure Surface Activity and the Tendency to the Formation of Submicrons. I. TRAUBE (Kolloid Z. 1923 32 22-24; cf. A. 1912 ii 858; 1915 i 105).-It has been shown previously that salts of alkaloids are molecular dispersed in aqueous solution (Zoc. cit.) and because of their ionic charge have a large cohesion pressure; they are therefore unable to form sub- microns and have no surface activity. In every respect the reverse is the case for free non-ionised alkaloids. It is now shown that the salts of fatty acids are similar to the salts of alkaloids in the above respects.With the exception of formic acid the free fatty acids have a small cohesion pressure and have a surface activity and from butyric acid upwards form submicrons. Here as in the case of the alkaloids the cohesion pressure decreases with increasing molecular weight whilst the surface activity and the ability to form submicrons increases. The lower fatty acids including propionic acid do not form submicrons whilst butyric acid forms many submicrons and the higher fatty acids such as nonoic decoic and undecoic acids exist in both a surface active and an inactive form. Substances such as amyl alcohol octyl alcohol phenol creaol,GENERAL AND PHYSICAL CHEMISTRY. ii. 127 aniline and xylidine have a considerable cohesion pressure and their concentrated solutions contain submicrons and molecular dispersed particles whilst hydrocarbons and alkyl halides have small cohesion pressures and in aqueous solutions exist mainly as submicrons.From the above facts the author claims general validity for the rule previously put forward. The smaller the cohesion pressure the greater is the surface activity and tendency to form submicrons. J. F. S. Films. Spreading of Liquids and the Spreading Co- efficient. WLLLIAM D. HAREINS and AARON FELDMAN ( J . Amer. Chem. Soc. 1922 44 2665-2685).-1t is found that the spreading of films is in general related to what is defined thermodynamically as the spreading coefficient. Liquids for which the value of this coefficient 8 is positive will spread whilst those for which it is negative will not spread. Actually the value of the coefficient refers to the system spreading liquid-substance on which the spreading occurs and may be quite different when A spreads on B from what it is when B spreads on A .For example most organic liquids have positive coefficients with reference to spreading on water and therefore will spread into a film ; but water has a negative coefficient with reference to most organic liquids and will not spread over them. The value of the coefficient X is defined by the equation AS'= Wa- W in which Wa is the work of adhesion for the interface of the two liquids and W the work of cohesion of the liquid which is applied to the surface of the other liquid or solid on which the spreading might occur. Thus a liquid will not spread if its work of cohesion which indicates its attraction fqr itself is greater than the work of adhesion which indicates its attraction for the substance on which the spreading will not occur.The values of Wa and W are given by the equations W ~ = Y ~ + Y ~ - Y ~ ~ ; Wc=2yb so that the value of the spreading coefficient may be entirely defined in experimental terms by the equation #=yU- (yb+yab) where a indicates the liquid which is spreading on the hquid or solid represented by b. A large number of experiments have been made on the spreading of organic liquids on the surface of 'water on the spreading of water on the surface of organic liquids and on the spreading of water and organic liquids on the surface of mercury. The results show the importance of the spreading coefficient as a criterion of spreading.Unimolecular films are produced on water only when the spreading coefficient has a relatively high value. Since these high values seem to occur only when the spreading substance contains a polar group in its molecules it is concluded that the presence of such groups is essential for spreading on water to a unimolecular film but not at all essential for the production of a film which is thicker than this. Contrary t o the generally held opinion benzene is found to spread on a clean water surface. The non-spreading of organic liquids on water is brought about by the presence in the organic molecule of chlorine bromine iodine doubly-linked sulphur phenyl and the group =CS. Liquids which do not spread on water are insoluble in it but insolubleii.128 ABSTRACTS OF CHEMICAL PAPERS. liquids may spread on water. The addition of camphor to water appears to reduce the value of the spreading coefficient; so that many liquids which have small positive coefficients on water will not spread on water containing camphor but those which have coefficients sufficiently high are found to spread. The values of the spreading coefficients of water and organic liquids on mercury are in every case investigated found to be positive. Water and twenty- two of the other liquids were tested with reference to their spreading on pure mercury and in agreement with their positive coefficients were found to spread. The coefficients for the spreading of mercury on water and organic liquids are all negative. This corresponds with the fact that mercury will not spread on their surface.Since the free surface energy of almost all inorganic solids is high their work of cohesion is high and the work of adhesion is also high with reference to practically all liquid substances. Since the work of cohesion in water and organic liquids is in general low the values of the coeficients of spreading of these liquids on such solids should be positive and in general the value should be high. Thus the spreading of these liquids should occur on such solids when the surfaces are pure. The frequently occurring phenomenon of non- spreading is thus indicated to be due to the presence of an already existent film on the solid substance. The removal of such films may be brought about by vaporisation or by the more common process of substituting one film for another.This is the ordinary function of soap soap solutions and other cleansing agents. It is difficult for petroleum to penetrate sands which have been wetted by water and for water to penetrate sands which have been wetted by petroleum although either substitution may be effected in time. Many oil wells cease to produce petroleum because the sand becomes wet with water. Lubrication and many other phenomena depend on the wetting of solids by films. Measurement of Adsorption Processes by Means of an Interferometer. OTTOMAR WOLFF (KoZloid Z. 1923 32 17- 19).-Experiments are described to show that for industrial purposes an interferometer may be used to ascertain the amount of colloid adsorbed from solutions by any given adsorbent.J. P. S. WOLFGANG OSTWALD and RAMON DE IZAGUIRRE (Kolloid Z . 1923,32,57-64).- In answer to the criticisms of Gustaver (this vol. ii 57) the authors admit that in their recent paper they have interchanged the values u and u as used by Williams (Medd. Nobel-Inst. 1919,2 No. 27 1) owing to want of clearness in that paper. The authors deny that the equation which is put forward in their paper is the same as that due to Williams. The equation put forward by Williams is special and relates to a single case only whilst that due to the authors applies to three cases. In the best investigated case the adsorption of acetic acid solutions by charcoal the deduction made by Williams that u0=-a when c = l does not hold. The new equation furnishes more and other results than that of Williams.The necessity of differentiating between relative and absolute J. F. S. General Theory of the Adsorption of Solutions.GENERAL AND PHYSICAL CHEMISTRY. ii. 129 thicknesses of layers in the investigation of adsorpticm layers is emphasised. In the adsorption of colloid particles the adsorption layer cannot be unimolecular in thickness; it must be at least uni- micellar. The adsorption layer may have very different thicknesses depending on the size of the absorbed particles and on the amount of water which is adsorbed a t the same time. The assumption of Gustaver that the adsorption layer has a maximum thickness of one molecule is further refuted by the ultramicroscopic observations of Traube and Klein (A. 1921 ii 683) on adsorption layers of surface active emulsoids which vary up to 0.01 mm.thick. J. F. S. The Sorption of Iodine by Carbons Prepared from Carbo- hydrates. JAMES BRIERLEY FIRTH (T. 1923 123 323-327). The Absorption of Moisture by Coal (and other Fuels). I. A Relation between Degree of Humidity in the Air and Moisture Content of Coal. BURROWS MOORE and FRANK STURDY SINNATT (T. 1923 123 275-279). Adsorption of Toluene Vapour on Plane Glass Surfaces. EMMETT K. CARVER ( J . Amer. Chem. Soc. 1923 45 63-67).- Isotherms for the adsorption of toluene vapour on plane glass surfaces a t 0" have been obtained. The glass used wits after thorough cleaning kept a t 200" in a vacuum for twelve hours and any gas set free removed by a mercury vapour pump. Pressure measurements were made with the author's modified Shrader and Ryder optical lever manometer (this vol.ii 148). The results are generally in agreement with Langmuir's adsorption formula (A. 1918 ii 430) and indicate that the adsorbed layer is not more than one molecule thick. J. F. S. Fixing of Organic Dyes by Inorganic Substrates. H. RHEINBOLDT and E. WEDEKIND (KoZZ. Chem. Beihefte 1923 17 115-188).-The literature dealing with the fixing of organic dyes by insoluble inorganic substances has been collected and discussed. It is shown that acidic and basic dyes exhibit a different behaviour toward similar substrates. In particular substrates of acidic character are only fast dyed by basic dyes whilst acidic dyes only fast dye basic substrates. The results of various authors which appear to be a t variance with the above rule are in reality not so since they do not refer exactly to the same thing.A large number of experiments with many dyes and inorganic gels have been carried out and give results entirely in agreement with the above rule. This rule is not only true for acidic and basic oxides of which the fol- lowing were examined silica and tin titanium zirconium thorium and cerium dioxides ; aluminium chromium and iron sesquioxides ; and glucinum zinc magnesium and lead monoxides; but also for sulphides (arsenic antimony and cadmium) and silver chloride. In no case was a dye from both classes fixed with the single excep- tion of amorphous carbon. The electro-endosmotic migration of the dyes and inorganic substrates was investigated and it is found that fast dyeing only takes place between substrata and dye whenii. 130 ABS!E'RACTS OF CHEMICAL PL%PEWJ.they are oppositely charged. The authors are of the opinion that the unsaturated valency forces of the crystal lattice of the absorbent are responsible for the fixing of the dye. Since these valencies are identical with the normal chemical valency the behaviour of the substrate is explained. And since the valencies are of an electro- static character the parallelism of the electro-endosmosis and the adsorption is understandable. The fixing therefore consists in the binding of the dye to the substrate to form a unimolecular layer of a molecular additive compound. This process the authors term adsorption by dectro-affinity. It is held that the adsorption by electro-aeity is not restricted to substances which have ordered crystal lattices and the charge of sols gels and other colloidal material is attributed to the action of the same surface valencies.J. F. S. Exact Process for the Determination of the Coefficient of Diffusion in any Solvent. ERNST COHEN and H. R. BRUINS (2. physikal. Chem. 1923 103 349403).-The authors have summarised and criticised the method available for the determination of the coefficient of diffusion. A process for the exact determination of the diffusion coefficient has been devised. The apparatus consists of six thick glass plates of the same diameter which fit exactly on a fkm central axis. The four middle plates are firmly fixed and three holes bored through them so that in each plate there are three holes relatively in the same position.These plates are placed between the other two which constitute a base and a cover plate. The hole in the lowest bored plate is filled with the liquid of which the diffusion is to be measured by means of a small hole which can be brought above it by rotating the necessary plates. The other three plates with holes are brought into such a position that the holes in them are above one another but not above the hole in the lowest plate and filled with the solvent. The arrangement now is that of two tubes filled with liquids which by rotation of the bottom bored plate may be brought into contact. When the whole apparatus has reached the required temperature the liquids are brought into contact and the diffusion commences. After a sufficiently long period the plates are twisted so as to cut the column of liquid into four isolated parts and the composition of each is estimated by the Rayleigh Lowe interferometer.It is claimed for the apparatus that it may be used for all types of liquids of which only small quantities are necessary. It may be used a t any temperature over a wide range and there is no error due to vibration or shaking when the liquids are brought into contact. By the use of an air thermo- stat the temperature is known and may be kept constant to 0.03". The error of the method is not greater than 0.3% and individual measurements are reproducible to O.l-O.3%. Validity of the Stokes-Einstein Law for Diffusing Mole- cules. ERNST COHEN and H. R. BRUINS (2.phy8ikc-d. Chern. 1923,103,404--450) .-The validity of the Stokes-Einstein equation for the diffusion in solutions at various temperatures has been investigated by means of the diffusion apparatus previously J. F. S.GENERAL AND PHYSICAL CHEMISTRY. 5. 131 described (preceding abstract). The pair of liquids tetrabromo- ethane and tetrachloroethane has been used and the diffusion velocity measured st temperatures from 0" to 50". The viscosity of tetrachloroethane has been determined over the same temperature range with a maximum error of 0.05%. Divergences from the Stokes-Einstein law have been observed which are a t least three times as great as the experimental error. The divergences are in the sense that the temperature coefficient of the velocity of diffusion is smaller than would be expected.The following values of the relative viscosity of tetrachloroethane are recorded 0" 1.6219 10*Oo 1.3113 15" 1.1924 25" 1.0000 35" 0.8541 and 50" 0.6917. The absolute fluidity of tetrachloroethane is given by the formula +/T=O- 13796 ( 1 + 0.0 191 71 8+0~OoOo092582). The Capabilities of the Rapid Dialyser. A. GUTBIER J. HUBER and W. SCHIEBER (Chem. Ztg. 1923 47 109-llO).- Further investigation of the rapid dialyser described previously (A. 1922 ii 551). The effect of using tap water instead of distilled water for the outer liquid was studied and it was found that 80- 90% of the electrolytes can advantageously be removed from colloidal solutions by dialysing against tap water after which point distilled water must be used.Experiments indicated that dialysis was more efficient the greater the speed of rotation of the membrane and stirrer ; 100 revolutions per minute was satisfactory with slightly greater efficiency a t 150 per minute. Generally ill flow of 5 litres of water per hour in the outer vessel is sufficient. The use of more than 10 litres per hour produced no corresponding increase in the rate of dialysis. G. F. M. The Law of Solution. PAUL MONDAIN-MONVAL (Compt. rend. 1923 176 301-304).-Measurements made with a very soluble salt sodium nitrate show that it obeys very exactly the equation established by Le Chatelier for the solubility of salts in water (A 1885 340; 1894 ii 272). Solubility and Chemical Constitution. H. J. PRINS (Rec. trau. china. 1923,42,25-28).-1t has been concluded by Harkins (A.1921 ii 242) and by Langmuir (A. 1917 ii 19) that adsorption and solubility are closely related. Both authors attribute orienta- tion phenomena exhibited by organic substances with water to the tendency of the polar group to dissolve in water. It is pointed out that the arbitrary circumstance that these researches were carried out with water and an organic substance containing a group more or less similar to water may lead to erroneous conclusions. With organic acids and water solubility and adsorption are both caused by the same group but this is not generally the case. A number of examples are given showing that solubility in hydrocarbons such as light petroleum depends not on polar groups but on saturated hydrocarbon groups. Solubility depends in general on similnrity in kind and number of atoms present in the molecules of the substances in question.Adsorption represents a case of hetero-complex formation whilst in solution the complexes have the character of homo-compounds. E. H. R. J. F. S. W. G.ii. 132 ABSTRACTS OF CHEMICAL PAPERS. Contraction on Solution of Various Substances in Water. JITENDRA NATH RAKSHIT (Reprint Indian Assoc. Cultivation Sci. 1917,3 pp. 1-21),-Makinguse of data from Landolt and Bornstein’s tables the author has calculated the contraction which takes place when 100 g. of various substances are dissolved in various quantities of water. The values have been calculated for sulphuric acid nitric acid formic acid stannic chloride acetic acid methyl ethyl propyl isobutyl and isoamyl alcohols glycerol acetonitrile acetone nicotine ammonia hydrogen chloride sodium and potassium hydroxides sodium chloride tartaric acid chloral hydrate phenol sucrose Izvulose dextrose maltose and invert-sugar.In some cases the contraction increases with increasing dilution whilst in others the contraction increases passes through a maximum and then decreases with increasing dilution. Effect of Scratching the Wall of a Vessel with a Glass Rod. L. DEDE (2. Elektrochem. 1922 28 543); ROBERT FRLCKE (ibid. 1923 29 44-46).-A continuation of the controversy on the cause of crystallisation when the walls of a tube containing a solution are rubbed with a glass rod (cf. A. 1922 ii 692 744). J. F. S. J. F. S. Viscosimetric Researches on Lyophilic Sols.H. G. BUNGENBERG DE JONG (Rec. trav. chim. 1923 42 1-24).-The greater proportion of viscosity measurements recorded in the literature cannot claim an accuracy of more than a few per cent. The conditions necessary to attain an accuracy of 0.1 to 002% are discussed and in particular the two most important sources of error the systematic error of the viscosimeter and the method of setting the instrument. For a given capillary there is a maximum average rate of flow for a given liquid so that the deviation from Poiseuille’s law shall not be greater than 0.1%. A formula for calculating this rate was given by Griineisen (Wiss. Abh. Phys. Tech. Reichanstalt 1905,4,151). By means of this formula the systematic error of the viscosimeter and the necessary length and fineness of capillary can be calculated.The error of setting can be minimised by fixing the instrument so that the line joining the centres of the upper and lower reservoirs in the Ostwald viscosimeter is vertical instead of one of the limbs. Measurements of viscosity recorded in the literature are subjected to a general criticism and in particular the work of Hatschek on the viscosity of gelatin sols (A 1911 ii 98; 1913 ii 835) and that of Rothlin (A. 1920 ii 18) is discussed. Hatschek observed with a number of lyophilic sols that the viscosity depends on the rate of flow or shear and he supposes that this phenomenon supports the theory of a dodecahedra1 structure of concentrated lyophilic sols. Rothlin divides lyophilic sols into two groups one of which follows Poiseuille’s law whilst the other does not.These deviations are to be ascribed to the formation of larger aggregates in the sol through gelation; these aggregates according to the conditions of flow can be broken down to different ,extents and so give rise to the observed irregularities. This explains the fact in the case of both Hatschek’s and Rothlin’s abnormal sols that theGENERAL AND PIEYS1CA.L CHEBZISTRY. ii. 133 viscosity increased with time due to progressive gelation. At higher pressures such systems would approximate more,md* more closely to Poiseuille's law as Rothlin found. It is,concluded that for viscosimetric measurements to have any value the,system under examination must not only follow Poiseuille's law but the disperse phase must retain its stability. Experiments with agar sols show that at 50° that is above the gelation temperature agar sols follow Poiseuille's law within 0.2% although a t 27" deviations of more than 100% are shown.Moreover above the gelation temperature all hysteresis phenomena are absent and mechanical treatment has no influence on the viscosity. The only alteration in viscosity with time shown by these sols is a slight decrease due to hydrolysis of the disperse phase. When such an agar sol is diluted with electrolytes a final equilibrium is reached immediately. It is suggested that the term sol should exclude all liquid systems (1) which show deviations from Poiseuille's law; (2) where the viscosity is influenced by mechanical treatment (3) where gelation coagulation and ageing phenomena generally are present.E. H. R. Topo-chemical Reactions. Crystal Formation in Colloidal Metals. V. KOHLSCHUTTEB and K. STECK (2. Elektrochem. 1922 28 554-568).-The frequent formation of silver crystals in solutions of colloidal silver has been explained partly on thermo- dynamic grounds as the result of solubility differences between silver particles of different sizes and partly as a result of the formation of crystal aggregates of the ultramicroscopic crystalline particles due to action of a molecular field. Both views are open to criticism; on the one hand on account of the excessively small solubility of metallic silver and on the other because of the constitution of the surface of colloidal particles. The author is of the opinion that chemical reactions aze responsible for the crystallisation.It is shown that in eighteen months definite silver crystals form in Lea's sol but in pure sols prepared by the reduction of silver oxide with hydrogen no silver crystals were visible until the sol had been kept for twelve years; the same applies to gels which are free from electrolytes and protective colloids and are preserved under water. Well-formed polyhedra are produced by the action of ferric-ions or silver-ions on coagulated gels and other forms of colloidal silver. Also the reduction of a silver-ibn solution with ferrous-ions within a definite range of concentration produces a transient colloidally- dispersed metal which speedily forms crystals. The localisation of the reaction by adding a solid ferrous salt to a solution of silver-ions or by adding a solid silver salt to a solution of ferrous-ions accelerates the crystal formation.In keeping with the experimental resulfs the formation of crystals from colloidal solutions is to be regarded as due to a maturing process in consequence of the silver of the micella entering into the reversible reactions Ag+Fe'" ;t Ag' + Be'' and Ag+Ag' Z Ag,' whereby the pressing together of the reaction products in and on the colloidal particles is probably determinative af the commencement of the reaction and also of the specific form- VOL. CXXIV. ii. 6ii. 134 ABSTRACTS OF CHEMICAL PAPERS. ation of the crystalline silver. Observations on various oxides and sulphides lead to the view that in the formation of crystals in colloidal systems electromotive actions play a part.These are due to the formation of concentration cells in the colloidal systems. J. F. S. The Constitution of Colloidal Gels. J. DUCLAUX (BUZZ. SOC. chim. 1923 [iv] 33 36-43).-A theory of the constitution of reversible gels is developed in which it is suggested that they are composed of three elements the fluid which may be water or some other solvent an insoluble solid forming with the fluid an irre- versible gel or sponge-like structure of ultra-microscopic cells and a soluble solid dissolved in the solvent of the gel. The mole- cules or micellae of this substance which may be either crystalloid or colloid are too large to be able to escape from the cellules of the sponge but they are small enough for their solution to have a certain osmotic pressure in relation to the pure solvent.This solution is the " plasm " of the gel and its swelling and expansion in a solvent are due to the osmotic pressure of the plasm. The limit of expansion is reached when equilibrium is attained between this osmotic pressure and the cohesion of the cellular structure of the gel. If the osmotic forces are strong enough continued inflation of the cellules may result in the dissolution of the gel and the separation of the soluble and insoluble constituents. The mechanical properties of the gel will evidently depend on the relative proportion of the two solid constituents in gum arabic or nitro-cellulose solutions prepared in the warm ; the insoluble constituent is almost absent and the tendency to gel formation is minimum but in gum-tragacanth or cellulose-nitrate solutions prepared in the cold the insoluble constituent dominates and manifests itself by gel formation or high viscosity.The Influence of a Dissolved Crystalloid on the Rigidity of Gels. F. MICHAUD (Cmpt. rend. 1922 175 1196-1198).- By means of a method recently described (ibid. 1922 174 1282) the author has measured the rigidity of gels the moduli of which were less than any previously measured. The dissolved substances were added in solution to the liquid gel the whole being allowed to set. The rigidity of gelose or gelatin gels is considerably decreased by the presence of acids or bases. In the case of gelatin a strong acid exerts a more marked effect than a strong base whilst the converse is the case if the gel is dilute.The curves obtained show that the action of the acid is a linear function of the concentration of the gel; that of the base is parabolic so that addition to a gel of increasing quantities of base or acid eventually causes the base to exhibit a greater influence than the acid for equimolecular quantities. The disposition of the curves obtained for gelose is in the inverse sense. The author suggests that these results are consistent with the amphoteric properties of gelatin and that by analogy gelose should be regarded as amphoteric its basic being stronger than its acid function. The action of salts on the gel depends primarily on the amount hydrolysed for those which G. F. M.GENERAL AND PEXSICAL CHEMISTRY. ii. 135 are not hydrolysed the molecular lowering of rigidity is about one-tenth that of an acid or base.The action of organic sub- stances is variable ; sugars and glycerol have practically no effect urea urethane and acetamide act similarly to mineral salts whilst resorcinol quinol and above all tannin bring about a very much greater decrease than an acid or base. H. J. E. Colloid Chemistry of Urate Jellies. E. KEESER and H. ZOCHER (Ko17. Chem. Beihefte 1923 17 189-217).-An investig- ation of urate jellies particularly those of lithium and sodium. It is shown that the jelly-forming urates belong to the class of electrolyte colloids and have properties which are parallel with those of soaps and similar substances. Microscopic examination of lithium urate jellies shows the presence of long optically aniso- tropic negative doubly refracting jelly particles and also of radial structures which extend into the rest of the jelly mass. The addition of methylene-blue to the long jelly particles produces a dichroic coloration and the structure becomes fibrous.The dis- persion of the double refraction is abnormal. The long structure of the particles cannot be confirmed by ultramicroscopic examin- ation because of their size. Solutions of urates cannot be obtained in a viscous state like the anisotropic sols of vanadium pentoxide and benzopurpurin neither do the urate solutions show streaming double refraction nor magnetic double refraction. Before lithium urate solutions pass into jellies they become turbid and after the jelly has formed the turbidity for the most part disappears.It is suggested that the turbidity is due to droplets formed by an unmixing of the solution. Mechanically effected changes in the jellies are irreversible that is after displacement the jelly does not resume its original form when the displacing force is removed. The residue obtained by subjecting the jellies to pressure shows but slight swelling power. The rigidity of the jellies increases with increasing concentration of the solution of lithium urate from which they are formed. The rigidity of jellies of constant composition increases with increasing addition of a lithium salt and the transformation into the crystalline condition takes place more slowly the more rigid the jelly. In all cases crystallisation commences a t a number of isolated but equally distributed points throughout the jelly mass.The addition of non-electrolytes such as carbamide sugar glycerol or alcohols reduces the rigidity of the gels increasingly with increasing concentration and retards the crystallisation generally. Carbamide is exceptional inasmuch as it accelerates the crystallisation. Protective colloids are without effect on the jellies. Examination of the jellies by X-rays shows that particles of sufficient size to produce Rontgen interference figures are absent whereaa a similar examination of crystalline lithium urate gives very broad interference bands which shows that the true size of the particles is considerably less than that of the needles visible in the microscope. Lithium urate is a negatively charged colloid. .The residues obtained by drying the jellies are colloidal in character and have the power of adsorbing 6-2ii.136 ABSTRhCTS OF CHEMICAL PAPERS. gases. Thus 1 g . of lithium urate will adsorb 0.5 C.C. of nitrogen at atmospheric pressure. Interfacial Tension between Gelatin Solutions and Toluene. S. E. SHEPPARD and G. S. SWEET ( J . Amer. Chern. Soc. 1922 44 2797-2805) .-The general relationship of the orientation of specific atom groups in the molecule to the emulsoid colloid state is discussed. A number of experiments on the separation of gelatin at a benzene-water interface have been carried out ; these consisted in shaking l.Oyo 0.1% and O * O l ~ o aqueous solutions of gelatin with an equal volume of benzene a t 30" 40" and 50" and measuring the volumes of the resulting benzene water and foam phases.The foam or interfacial layer consists of benzene dispersed in and protected by hydrated and aerated gelatin and is partly stabilised. In further experiments air was excluded and toluene substituted for benzene and here it was found possible to shake the liquid without much separation of the gelatin in the toluene although a considerable amount of toluene was emulsified in the gelatin solution. The stability of the gelatin foam a t various hydrogen-ion concentrations was found to increase from both sides of the isoelectric point and to be most stable at this point. The interfacial tension of gelatin solutions of varying hydrogen- ion concentrations has been determined a t 30" 35" and 40" by measuring the drop number of the solution. The drop number- hydrogen-ion concentration curves all lie above the corresponding curves for water and all the gelatin solution curves show a char- acteristic break near the isoelectric point the maximum reduction of interfacial tension being at pH=4.8.Classification of Disperse Systems in Connexion with the Mechanism of True and Colloidal Solution and Precipitation. P. P. VON WEIMARN (KoZZ. Chem. Beihefte 1923 32 72-114).- A survey of dispersoid chemistry in which classifications of disperse systems according t o the state of aggregation of the particles and according to the " external " degree of dispersion are put forward. The imperfect nature of the static classification is pointed out and a large number of tables are given of the appearance of pre- cipitates of sparingly soluble substances at various times after their formation.J. F. S. Velocity of Flocculation of Selenium Sols. H. R. KRUYT and A. E. VAN ARKEL (Kolloid Z. 1923 32,29-36).-The velocity of flocculation of selenium sols of various concentrations by solutions of potassium chloride and barium chloride of various concentrations has been determined at a series of temperatures from 15" to 20". It is shown that the region of rapid flocculation for potassium and barium chloride lies a t very high concentrations of these electrolytes. This result has been confirmed by measure- ments of the boundary charge of the sols. The results show that Smoluchowski's theory is valid in the region where the velocity of flocculation is not far removed from that obtaining when the colloidal particles are totally discharged.The results deviate J. F. S. J. F. S.QFJ?ERAL AND PHYSICAL CHEMISTRY. ii. 137 strongly from this theory when smaller concentrations of elecfrolytes are used; the divergence consists in a continuously decreasing velocity of flocculation. The boundary charge of the sols has been determined in the presence of a solution of various concen- trations of potassium chloride barium ohloride potassium hydr- oxide and hexamminecobaltic chloride. It is shown that the addition of hydrazine increases the boundary potential and that after the addition of ten m.mols. of barium chloride the particles still possess a charge. The addition of potassium hydroxide increases the boundary potential and it is therefore suggested that the like action with hydrazine is due to hydroxyl-ions.CH. COFFIQNIER (Bull. Xoc. chim. 1923 [iv] 33 128-132).-The thickening or swelling of the paint in oil paintings is a colloidal phenomenon and is attributable to the action of the resin acids in the varnish on the lead or other heavy metal compounds used in the paint whereby a colloidal metallic complex is formed which behaves as a reversibre gel. The phenomenon is particularly noticeable and rapid with colophony varnishes but it also occurs with other materials possess- ing free acidity. Congo and kauri gums for example whilst not behaving in this way with white lead show the reaction with litharge or zinc white but if can be prevented in all cases by eliminating the free acidity of the resin or gum.For this purpose neutralisation with calcium carbonate or hydroxide is not so satisfactory as esterification as the “ neutralised ” material has still a certain acid value which is not reduced to zero even by calcium hydroxide. Esterification of the gum or colophony with glycerol furnishes a material from which a neutral varnish can be prepared and the troublesome phenomena above referred to then no longer occur even with litharge or zinc white. General Nephelometry. M. U. C. Al. LEDNICK$ (KoZloid Z. 1923,32,12-17).-A general discussion of the application of nephel- ometry to colloidal solutions. It is shown that in comparisons it is essential that the illumination should be uniform and symmetrical ; the beam of light should be horizontal and parallel.The surfaces of the solutions should be the same height and the concentration such that Beer’s law holds and so low that the boundaries of the Tyndall cone are sharp. The light should be monochromatic and in the case where the two solutions have not the same colour a filter must be used before the light reaches the eye. Non- Uni- and Bi-variant Equilibria. XXII. I?. A. H. SCEREINEMAKERS (Proc. K . A M . Wetensch. Amsterdam 1923 25 341-353).-1n continuation of previous work (A. 1922 ii 430) the author has investigated mathematically the condition deter- mining the equilibrium of n components in a system comprising n+l phases when the quantity of one of the components is infinitesimally small and has examined more especially the effect of a small quantity of added substance on a non-variant equilibrium.Expressions are derived for the partition of the added substance J. F. S. Colloidal Phenomena in Paintings. G. 3’. M. J. F. S.ii. 138 ABSTRACTS OF CHEMIOAIi PAPERS. between the various phases and for the temperature and pressure changes respectively occurring on such addition. F L and C representing the respective phases it is shown that when a sub- stance x is added to a system in non-variant unary equilibrium E(x=O)=P+L+Q an equilibrium arises which is represented on the P-T diagram by a curve commencing a t the non-variant point of the equilibrium E(s=O). When the added substance occurs in the liquid phase only this curve corresponds with the curve L=P+C of the system E(x=O). If the added substance occurs both as liquid and vapour then the equilibrium curve is situated in region P and its direction is determined by the partition of x between the vapour and liquid phases.When the added substance occurs both in the liquid and solid phases the curve is situated in the region G and its initial direction is determined by its partition between mixed crystals and liquid. In the case when the added substance occurs in the three phases the curve may be situated in any of the three regions L F or G . Its direction is then defined by the partition of the added substance between the three phases. J. S. G. T. Determination of the Chemical Equilibria between Various Stages of Oxidation by Means of Electrometric Measure- ments. I. The Equilibrium between the Sulphates of Bi- Ter- and Quadri-valent Manganese in Sulphuric Acid Solution.G. GRUBE and K. HUBERICH (2. Elektrochem. 1923 29 8-17) .-Oxidation potential measurements of mixtures of the sulphates of manganese in sulphuric acid of various concen- trations have been made for a large number of solutions at 12". It is found that in a solution which contains 0.05 g. atom of man- ganese in a litre of 15N-sulphuric acid when at 12" the ratio of the stages of oxidation is 1 1 the following oxidation potentials exist r o M p + Mn~~=1-511 volts C O ~ ~ I I I -+.-Iv= 1.642 volts and ~~~~n -+ M n ~ ~ = 1.577 volts. These potentials are slightly dependent on the total concentration of manganese but strongly dependent on the concentration of the acid. Increasing concentration of acid displaces the values to less positive potentials.Using the measured potentials the equilibrium constant of the reaction Mn,(SO,) .Z MnS04j-Mn(S0,) was calculated. This value also changes wth the acihty and the total concentration of manganese and has been determined for a total manganese concentration of 0.05 g. atom per litre in concentrations of sulphuric acid varying between 9.1N and 24.2N. From the determinations it is shown that a O*O5M-solution of manganic sulphate in 9.1N-sulphuric acid decomposes according to the above equation to the extent of 36% but in 24.2N-sulphuric acid to the extent of 6*7% that is the equilibrium is displaced toward the left of the equation with increasing concentration of acid. The existence of this equilibrium is the cause of the abnormal behaviour of manganic sulphate on hydrolysis.With this substance hydrolysis produces manganous sulphate and a hydroxide of quadrivalent manganese. This is due to the fact that of the components of the equilibrium quadri-GENERAL AND PHYSICAL CHEMISTRY. ii. 139 valent manganese sulphate is most easily hydrolysed whereby the equilibrium is disturbed and still more sulphata is produced so that the reaction takes place completely from left to right. J. F. S. Equilibrium Gelatin-Hydrochloric Acid. R. DE IUGUIRRE (Kolloid Z. 1923 32 47-51).-1t is shown that the view put forward by Lloyd and Mayes (A. 1922 i 280) on the basis of measurements of the hydrogen-ion concentration in solutions of gelatin containing hydrochloric acid that a t concentrations below 0.04N the hydrochloric acid is attached to the amino-group and at higher concentrations to the nitrogen atom of the poly- peptide group cannot be substantiated from the measurements. So far as the accuracy of the measurements permits it must be held that they point rather to a continuous curve for the hydrogen- ion combination curve.But from this it does not follow that a chemical combination has taken place between the hydrochloric acid and the gelatin for a logarithmic equation similar to the adsorption equation leads to a similar curve. It is also shown that the change of the electric charge of an adsorbent during an adsorption process can lead to curves of the most divergent type. Since such changes do take place during the adsorption of ions the point has to be settled whether the combination with ions is to be regarded as a chemical process or merely as an adsorptive process.J. F. S. (WE) G . MARCHAL (Cmpt. rend. 1923 176 299-301).-The decomposition of silver sulphate under the influence of heat gives rise to an equilibrium reaction forming a bivariant system which becomes univariant if care is taken to have in the gaseous phase only the gases coming from the decomposition. The author has made a study of this equilibrium under these conditions. Above 660° silver sulphate decomposes according to the equation and there exists in the gaseous phase a small amount of sulphur trioxide to satisfv the equilibrium The Dissociation of Silver Sulphate. Ag,SO,, = ~Ag*o,+S0,,+O,,aa .L 2SO e= 2~O,,&B+O,,fI Using the equation Q= [4*57(log K2-!0g K1)T1T2]/(T2-T,) the heat absorbed in the decomDosition is calculated as 82.4 cal. between 820" and 1000".Uiing Nernst's equation the values obtained are 103.9 cal. a t 820" and 103.2 cal. at 10oO". By means of the experimental results it is possible to calculate the state of equilibrium of the bivariant system for each temperature if it is arranged for the pressure of the oxygen at equilibrium to be equal to 1/5 atmos. pressure of the oxygen in the air. Equilibrium of the Reaction between Metallic Silver Cupric Chloride in Aqueous Solution and Solid Cuprous and Silver Chlorides. GRAHAM EDGAR and LAWRENCE S. CANNON ( J . Arner. Chem. Xoc. 1922 44 2842-2849).-The reaction CuCl+AgCl+H,O=CuCl,+H,O+Ag has been inves- tigated in the presence of hydrochloric acid of various coxwentrafion$ W.G.ii. 14-0 ABSTRACTS OF CHEMICAL PAPERS. at 25' and 40". The equilibrium constant ha,s been obtained from both sides. The method is t o shake the reagents together in coloured bottles and analyse the solution after equilibrium has been attained. The equilibrium constants have been calculated making use of the principle of "ionic strength" and the values 1 . 8 6 ~ 10-6 for 25" and 1-61 x for 40" obtained. From these values the increase in the heat content of the system is calculated by means of the expression AH= RT2d . log ,K/dT and the value -1755 cal. obtained. The increase of free energy of the system is calculated for 25" and the value AF=7820 cal. obtained. These values have been compared with the values obtained by Noyes and Ellis (A 1918 ii 27) Lewis and Lacey (A 1914 ii 521) and Noyes and Chow (A.1918 ii 214) and a moderate agreement has been found between the two sets of values. The present data afford a measure of support for the methods employed by Lewis and Randall (A. 1913 ii 29) in calculating the activities of mixed electrolytes. J. F. S. Liesegang Rings. I. Silver Chromate in Gelatin and Colloidal Gold in Silicic Acid Gel. EARL C. H. DAVIES ( J . Arner. Chem. Soc. 1922 44 2698-2704).-The author has in- vestigated the influence of gravity and light on the formation of silver chromate rings in gelatin and gold rings in silicic acid gel A jelly composed of 0.14 g. of potassium dichromate 4 g. of gelatin and 120 g. of water was brought into contact with a solution of 8.5 g.of silver nitrate in 100 C.C. of water the jelly being held in various positions so that diffusion could occur vertically down- ward and upward and also horizontally. It is found that diffusion is slowest when it operates against gravity but the effect of gravity may be counterbalanced by hydrostatic pressure. The mechanism of the ring formation is as follows. The silver nitrate diffuses into the gelatin and gives what appears to be an opaque region which in reality consists of opaque bands; these preliminary bands are further apart as the distance from the surface increases. These preliminary bands are due to the unequal rate of diffusion of the nitric acid and potassium nitrate produced in the reaction. The groups of silver chromate-potassium nitrate crystals which are seen microscopically to form are gradually broken up as the potassium nitrate diffuses away and the silver chromate particles become larger because of the oncoming silver nitrate.Hence the small bands lose their identity and the large bands are formed. Colloidal gold in silicic acid gel produced no rings when kept a t 0" in the dark for nine days but only isolated gold crystals. On placing these tubes in a powerful beam of light for an hour a band 1.5 cm. thick was formed. The band did not commence as a thin line and grow but the whole area developed a faint yellow colour at once and this grew in intensity as the exposure proceeded. A further tube of colloidal gold in silicic acid gel was covered with black paper and at distances of 9 cm.2 cm. bands were cut away. The tube was placed in a dark room and the light from an 80 watt lamp fell on it for nine days when slightly green colloidal bandsGENERAL AND PHYSICAL CHEMISTRY. ii. 141 developed at the openings. A similar tube showed no bands after keeping for six days in the dark but on exposure for a few minutes to an arc light bands developed a t the openings in the paper but no bands appeared between the openings. The tube was kept for for a further seven days in the dark a t 0". The paper was then entirely removed and the tube exposed to an arc light for three hours when a slight blue colour developed between the original bands. J. F. S. Liesegang Rings. 11. Rhythmic Bands of Dyes on Filter-paper and Cloth by Evaporation. Refractivity Sur- face Tension Conductivity Viscosity and Brownian Move- ment of Dye Solutions.EARL C. H. DAVIES ( J . Amer. Chem. SOC. 1922 44 2705-2709 ; cf. preceding abstract).-Rhythmic bands of dyes have been produced on filter-paper cotton cloth and unglazed porcelain by regulated evaporation. Solutions of some sixty-two dyes were used in o*04y0 and o.oo5~0 concentrations with several varieties of filter-paper. A table is given in which t'he following physical properties of the 0.04% solutions are recorded refractive index surface tension electrical conductivity viscosity and Brownian movement. The Tyndall cone and band formation are also investigated and the data recorded. It is shown that a uniform temperature and a gradual decrease in the rate of flow are the important factors in the formation of bands.It is probable that just before the band forms a film of oriented mole- cules is present. Calculation of Velocity Constants. A. L. TH. MOESVELD (2. physikul. Chem. 1923 103 481486).-The author describes a method of calculating the velocity constant of a reaction which is more accurate and less arbitrary than the generally adopted method. The velocity equation for a reaction of the nth order can be written in the form 1/(A -~)~=k't+l/A" where x is the concentration at time t and A a t t=O. The method consists in inserting the values of A-x and t in the equation for each measurement and so obtaining a series of equations with two unknowns k' and l/An. When these equations are solved by the method of least squares the value of k' is obtained which corresponds most nearly with the whole of the experimental results. Further from the divergence of the experimental value of l/(A-x)" and the value calculated from k' it is a t once shown whether the equation chosen is the correct one for the case under examination.A simplified method of working out the rather complicated calculations is given. J. F. S. The Speed of the Uniform Movement of Flame in Mixtures of the Paraffins with Air. WALTER MASON (T. 1923 123 K ~ R L GLASER (2. ungew. Chem. 1923 36 38).-The phenomenon of the roaring of the flame of the Bunsen burner is not a peculiarity of any particular gas but can be caused with any gas by sufficiently J. F. s. 200-214). The Roaring of the Bunsen Burner Flame. 6'ii. 142 ABSTRACTS OF CHEMICAL PAPERS. increasing the pressure above the normal whereby a corresponding increase occurs in the velocity of flow other things remaining equal.The conditions governing the phenomena may be expressed ai3 follows where v is the velocity of flow c the velocity of the pro- pagation of flame for the gas in question v' a factor depending on the buoyancy of the gas and c' on the preliminary heating to which the gas is subjected in the burner when v+v'< -(c+c') the flame strikes back; when v+v'=-(c+c') the burner burns normally and when v+v'> - (c+c') the flame roars. Piezo-chemical Studies. XVII. Influence of Pressure on the Velocity of Reaction in Homogeneous Liquid Systems. A. L. TH. MOESVELD (2. physikal. Chem. 1923 103 486-504).- The pressure coefficient of the velocity of reaction of the change 5HBr+HBr03=3Br,+2H,0 between the temperatures 1" and 39" has been determined.It is shown that for the temperature range examined it is independent of the temperature. The velocity of reaction a t a pressure of 1500 atm. is 15.4% less than that at 1 atm. pressure. The pressure influence is therefore negative and very much smaller than that observed in cases of hydrolysis carried out under approximately similar conditions. From this it is to be concluded that pressure exerts a specific influence on the velocity of reaction and this is not changed by changing the external conditions under which the reaction is taking place. G. F. M. J. F. S. Regularities in the Velocity of Vaporisation. W. HERZ (2. Elektrochem.1922 28 526-527).-1t has been shown recently by Volmer and Estermann that the velocity of vaporisation G is given by the equation G= 1 /d2;3 x p l / M / T where p is a constant M the molecular weight and T the boiling point in absolute degrees (A 1922 ii 193). This indicates that 1/m is proportional to G. The author has calculated the values of d M / T for a large number of substances and finds that the value increases steadily with the molecular weight in homologous series; it also increases with the replacement of hydrogen by chlorine. The removal of two hydro- gen atoms and consequent formation of a double Linking reduces the value whilst the formation of a treble linking causes a still further and much larger decrease. Ethers generally have much larger values than the corresponding saturated hydrocarbons. Solubility and Specific Rates of Hydrolysis of p p'-Dichloro- diethyl Sulphide in Water.ROBERT E. WILSON E. W. FULLER and M. 0. SCHUR (J. Amer. Chem. Soc. 1922 44 2867-2878).- The hydrolysis of p p'-dichlorodiethyl sulphide in water has been investigated. It is shown that the hydrolysis in contact with water is a two-phase reaction which affects only the molecules dissolved in the aqueous phase. The rate of the first stage of the reaction determines that of the second stage. Once steady con- ditions are established the concentration of the intermediate camyound automatically increases or decreases keeping the rate of the second stage just equal to that of the first stage. The J. F. S.GENERAL AND PHYSICAL OHEMISTRY.ii. I43 amount of intermediate compound present a t any time is extremely small and the time required to build up the equilibrium concen- tration is generally negligible. The simplest expression for the rate of hydrolysis at 25" in alkaline solutions where there is no tendency toward reversal is dc/dt=2KI(M)=0.304(M) where &/dt is the rate of hydrolysis in millimols. of hydrogen chloride produced per litre per minute and ( M ) is the concentration of gas in millimols. per litre. The second stage of the hydrolysis is sub- stantially non-reversible except in very concentrated hydrochloric acid solutions. The first stage is however reversible to a con- siderable extent even in the presence of dilute acids. This reversi- bility of one stage serves to retard but not to stop the reaction because the intermediate compound of the hydrolysis is being continually destroyed by the irreversible second stage.Indirect evidence indicates that the second stage of the reaction is catalysed in direct proportion to the hydrogen-ion concentration in acid solutions. Since the rate is also very rapid in alkaline solutions it is very likely catalysed also by hydroxyl-ions. The mathe- matical expression for the rate of hydrolysis in acid solutions is &/dt=K,(M) Tkl(I)(H*)(Cl')+k2'(I)(H*). A simpler but less obviously rational form of this equation is dc/dt=2k,(M)/( 1+ k3(C1')=0.304(1M)/( 1 +6*14(Cl'). This equation has been found satisfactory for a wide range of acid concentrations. The solu- bility of pp'-dichlorodiethyl sulphide in water a t 25" is 0.0043 mol./litre and on substituting this value in the equations above the rate of hydrolysis in saturated solutions is obtained.J. F. S. Velocity of Hydrolysis of Methoxymethyl Acetate. ANTON SKRABAL and MARIA BELAVI~ (2. physikal. Chem. 1923 103 451460) .-The velocity of hydrolysis of methoxymethyl acetate in O.1M-solution by 0.1 0.05 0.02 and 0-O1N-hydrochloric acid 0-1N-sodium carbonate and 0-1N-sodium metaborate has been determined a t 25" and the values obtained have been compared with the values previously obtained (A. 1921 ii 134) for the simple acetals methylal and methylene diacetate. The mixed acetal is hydrolysed much more rapidly in acid solution than the two simple acetals whilst the velocity in alkaline solution lies between that of the two simple acetals.Energetics of Sucrose Inversion. THOMAS MORAN and HENRY AUSTIN TAYLOR ( J . Arner. Chem. Xoc. 1922 44 2886- 2892) .-The effect of temperature on the potential difference of the normal hydrogen electrode is discussed and it is shown from E.M.F. measurements with acetic acid that it is approximately proportional to the absolute temperature. Measurements have been made on the very short ulfra-red absorption of aqueous solu- tions of sucrose dextrose and laevulose in the region 0*75-1.0 p. Sucrose and laevulose show a band a t 0-875 p which is not present with dextrose. The bearing of these results on the critical increment of sucrose dihydrate and on the mechanism of the inversion of sucrose has been discussed. J. F. S. J. F. S. 6'-2ii.144 ABSTRACTS OF (3HEMfCAL PAPERS. Process for Studying the Velocity of Formation of Pre- cipitates. ROGER G. Boosso (Cmpt. rend. 1923 176 93- 95).-A modified form of Jolibois’s apparatus for studying the mixture of liquids (A. 1920 ii 107) is used. The bottom limb of the Y-tube is cut off and the two side limbs are so adjusted that their orifices are 1 cm. apart. The liquids necessary to form the precipitate are run at the same rate down the side tubes and mix almost immediately. The resulting mixture is allowed to flow into a large volume of water saturated with respect to the precipitate the formation of which it is desired to study. This volume of liquid is held a t different distances below the point of mixing and thus the time for the formation of the precipitate is varied.The diluted mixture is filtered at once and the precipitate collected and weighed. The errors do not exceed 5%. W. G. Catalysts and Chemical Equilibrium. J. CLARENS (Bull. Soc. chim. 1923 [iv] 33,43-48).-Polemical. A reply to Durand’s criticism (A. 1922 ii ‘301) of the author’s original paper (A. 1922 ii 436). G. F. M. The Catalytic Action of Hydrogen-ions in the Hydrolysis of Esters. S. C. J. OLIVIER and G. BERGER (Rec. trav. chim. 1922,41 [ii] 637-645).-An examination of the rate of hydrolysis under various conditions of benzyl chloride a-chlorohydrin ethyl nitrate and methyl trichloroacetate showed that the presence of hydrogen-ions has practically no effect on the speed of the reaction in the case of the two first-named substances a very small effect with ethyl nitrate and a small but quite definite catalytic action with methyl trichloroacetate.The facts observed together with those described by Cavalier (A. 1899 ii 13) Wegscheider (A 1902 ii 493) and KIemenc (A. 1918 i 220) lead to the conclusion that hydrogen-ions have little or no effect on the hydrolysis of esters of strong acids. I n a brief discussion of the mechanism of the reaction the authors state that theories based on the supposed activation of the water by the acid (Rohland A. 1901 ii 152; Noyes and Sammet A. 1902 ii 498) are not satisfactory as water should also be activated in the case of esters derived from strong acids. The theory of formation of oxonium salts put forward by Stieglitz (A. 1908 ii 167) is preferred because an increase in the negative character of the group R in R-C0.O.R’ decreases the basic character of the oxygen and consequently diminishes the tendency to form such salts (cf. Kendall and Booge A.1916 i 707). It is uncertain whether the hydrolysis is effected by the ion RC0,R’-H or by activation of the ester at the moment of conversion into oxonium salt. €1. J. E. Catalase Action of Peroxydase. E. ABEL (2. Elektrochem. 1922 28 489496).-It is shown that peroxydase catalyses the reaction between potassium iodide and hydrogen peroxide only in the presence of hydrogen-ions; in faintly alkaline solution there is no acceleration of the velocity of reaction. The peroxydaseQ E N E U AND PHYSICAL CHEMISTRY. ii. 145 was obtained from horse-radish and is seen in the above-mentioned reaction to exercise the action of a catalase (cf.A 1920 ii 35 180). J. F. S. The Fine Structure of Atomic Nuclei and the Deviation from Coulomb’s Law in the Interior of the Nucleus. I. The Atomic Nuclei of Lithium and iss33eliwm. MAXIMILIAN CAMILLO NEXJBERGER (Ann. Physik 1923 [iv] 68 574-582).- A theoretical paper in which it is shown that the deviations from Coulomb’s law become smaUer as the atomic number increases (cf. Smekal Xitxungsber. Akad. Wiss. Wien 1920 130 149-157). In this paper the atoms of lithium (atomic weight=6) and isohelium are examined. The lithium atom is assumed to consist of two ai- particles (isohelium) rotating in a ring around a p-particle. This arrangement is stable and making allowance for the deviation from Coulomb’s law i t is shown that the heat of formation of one gram-atom of Lis=4.72~107 Cal.The heat of formation of isohelium from three hydrogen atoms is &=4-72 x 10s Cal. The deviation from Coulomb’s law is considerably greater for isohelium than for the Li6 nucleus. It is shown that B9 is unstable which is in agreement with Aston’s work on the isotopes of boron. The upper radius for the Li6 nucleus is 2.53 x 10-13 cm. and for isohelium 1-45 x cm. W. E. G. The Stability of Atomic Nuclei the Separation of Isotopes and the Whole Number Rule. WILLIAM D. HARKINS ( J . Franklin Inst. 1922 194 329-356 521-535 645-681 783- 814 ; 195 67-106 ; cf. A. 1922 ii 702).-A summary of previous work on the stability and methods of eeparation of isotopes and a review of the theory of Harkins and Wilson (A 1915 ii 543 544) of the evolution of atomic species from hydrogen atoms and a-particles and the experimental evidence in its favour.From the relative abundance of the different atomic species in meteorites and in the earth’s crust deductions are made as to the relative atomic stabilities and the part played by the ratio of the number of protons to electrons in the nucleus in determining the order of stability (cf. A. 1922 ii 490). Five stability principles are enunciated (1) no nucleus is stable unless the number of electrons it contains is equal to or greater than one-half the number of protons (N/P>0-5) (2) as the nucleus becomes more positive with reference to its net content of protons i t is essential for stability that it shall become more negative with respect to its relative content of electrons (3) the number of electrons in most nuclei is even (4) atomic nuclei and groups of protons and electrons in atomic nuclei are in general more stable when they contain an even rather than an odd number of protons and (5) elements of an even atomic number are much more abundant than those of odd atomic number.The determining factor for stability is the ratio NIP. The principles for the prediction of isotopes from the chemical or mean atomic weights are illustrated by means of the element lithium for which isotopes with atomic weights 6 and 7 should exist. E’or the hypothetical atom with atomicii. 146 ABSTRACTS OF CHEMICAL PAPERS. weight 5 N/P=0.4 and for that with atomic weight 8 N/P=0*625 which is higher than the ratio for any known atomic species.Hence it is concluded that these forms of lithium are incapable of existence The principle that the most abundant isotopes of elements with even atomic weights will also possess even atomic weights has received support from the work of Dempster on the isotopes of zinc and of Aston on the isotopes of tin. In general the most abundant isotope of an element has a charge and a mass equal to a whole number times the charge and mass of an a-particle. The original theory of Rutherford that the light atoms are built up mostly of particles of mass 3 was not justified. The mode of disintegration of the light atoms by the Rutherford method and the disintegration of the radioactive elements are discussed. Calcu- lations are made of the energy of disintegration of the radioactive elements.In conjunction with Lunn the loss of electromagnetic mass due to the approach of protons to electrons has been derived (cf. A. 1922 ii 703). The possibility of distinguishing between isotopes by spectroscopic measurements is considered and it is concluded that isotopes should differ chemically. A summary is given of the methods previously employed in the separation of the isotopes of neon chlorine and mercury and of the efficiencies of the processes of distillation diffusion and liquid centrifuging. Evidence is submitted of the separation of cadmium and zinc by a distillation method to the extent of 0.04 to 0.05 of it unit of the atomic weight. W. E. G. A Relation between the Atomic Numbers and the Atomic Weights of the Chemical Elements.F. LOEWINSON-LESSINB (Compt. rend. l923,176,307-309).-The sum of the atomic numbers of two adjacent elements starting from helium give the following relationships for the first twenty elements the atomic weight is equal to + or -1 to the sum of the atomic numbers of the element and of that which immediately follows it. Starting from scandium this atomic difference between the atomic weight in round numbers and the sum of the atomic numbers increases and reaches a value of 51 a t the finish but in certain groups of elements its value remains almost constant. There is in the horizontal rows of the periodic system a certain regularity in its increase. This correlation allows the atomic weights of the five elements not yet discovered to be foretold and atomic weights of certain elements to be corrected.W. G. Radicles and the Periodic Classification of the Elements. A. RIUS Y M I R ~ (Anal. Fis. Quim. 1922 20 496-500).-The atomic number of a radicle may be obtained by subtracting from the sum of the atomic numbers of its constituent elements twice the number of valencies concerned in its formation. For example in the case of ammonium the atomic number is 7+(4 x 1)-(2 x4)=3 equal to the atomic number of lithium. Atomic numbers for other radicles calculated in the same way enable them to be assigned to appropriate positions in the periodic classification. G. W. R.GENERAL AXD PIIYSICAL CREMISTRY. ii. 147 T. M. LOWRY (Rec. trav. chim. 1923,42,29).-The proposal of Centnerszwer for the intro- duction of a unit of atomic mass (ibid.1922 41 580) haa been anticipated by Sir W. H. Bragg (Proc. Php. Xoc. 1921 34 35) who proposed that the hgstrom unit of length 10-8 cm. should be made the basis of a unit of area of volume cm.3 and of mass lO-Z4g. The mass of an atom in Angstrom units is then 1-65 times its atomic weight. Molecular Dimensions Molecular Structure and the Viscosity of the Halogens and their Hydrides. HARRY SCHMIDT (2. Physik 1923 12 24-27).-An extension of the equations of Chapman (A. 1916 ii 416). The mean molecular collision area of chlorine bromine and iodine have been derived by Rankine (A. 1921 ii 192) from viscosity determinations and from these values on the assumption that the halogen molecule consists of two atoms in contact the atomic radii have been calcu- lated.From these figures and the radius of the hydrogen atom given by the Bohr theory the mean collision area of the hydrogen halides is derived and compared with data based on viscosity measurements. The agreement is satisfactory. On the other hand measurements of the viscosity of hydrogen give values for the mean collision area which are not in accord with the assumption that the hydrogen molecule consists of two hydrogen atoms in contact. W. E. G. The hgstrom System of Units. E. H. R. Magnetic Valency and the Radiation Hypothesis. F. T. PEIRCE (Phil. Mag. 1923 [vi] 45 317-323).-An inquiry into a possible mechanism of chemical change which would amign an effective r6le to radiation of a definite frequency. A theory of the valency bond is put forward which is based on the work of Oxley (cf. A. 1921 ii 82). The valency bond is due to the magnetic attraction between two ring or vortical electrons and can only be destroyed by the influence of radiation of the right frequency. The effects of temperature radiation and external illumination are discussed and compared and the conclusion is drawn that photo- catalysis should be observable only where the rate of reaction is determined by a dissociation. W. E. G. Transformations in Unsaturated Compounds. Negative Migration. A New Theory of the Conjugated System C:C.C:C. ALFRED GILLET (Bull. Soc. chim. Belg. 1922 31 365-375; cf. A. 1921 i 490 533 761).-A theoretical discussion in which the author maintains that by generalising two or three types of transformation of which several cases are known the properties of conjugated double bonds may be explained without assuming the existence of partial valencies. H. J. E. The Metallurgical Applications of Physical Chemistry. CECIL HENRY DESCH (T. 1923 123 280-294).-A lecture de- livered before the Chemical Society on December 14th 1922.ii. 148 ABSTRBCTS OF CHEMICAL PAPERS. The Identity of Geber. E. J. HOIXYA-RD (Nature 1923,111 191-193).-A criticism of Berthelot’s view now commonly held that Geber’s works are European forgeries of the thirteenth century ; the author considers the identity of Geber with Jiibir ibn Haiyiin (eighth century A.D.) to be extremely probable. The Identity of Geber. J. R. PARTINGTON (Nuture 1923 111 219-220 ; cf. preceding abstract).-An historical discussion in support of the probable authenticity of the Latin works ascribed to Geber. A. A. E. A. A. E. Improved Optical Lever Manometer. EMNETT K. CARVER (J. Amer. Chem. Soc. 1923 45 59-63).-The optical lever mano- meter described by Shrader and Ryder (Phy&d Rev. 1919 13 321) has been slightly modified whereby the sensitivity has been increased to 0.0001 mm. with an accuracy of about 0-0002 mm. of mercury. The modifications introduced are a tube of 44 mm. diam. instead of narrow as in the original apparatus ; this eliminates the error due to clinging of the mercury to the walls; a steel float instead of glass which eliminates irregular wetting of the float; the knife edges are replaced by steel points which prevent the changes which occur in the seating of the mirror support and so prevent a shift of zero; temperature changes were eliminated by placing the manometer in a thermostat with an optical glass window. J. F. S. The Production of Coloured Flames for Use with Spectro- photometers and Polarimeters. J. J. MANLEY (Phil. Mug. 1923 [vi] 45 336-337).-An apparatus is described for the intro- duction of aqueous solutions of salts acidified with hydrochloric acid into the Bunsen flame. This consists of a glass bulb of 20-30 C.C. capacity blown in the middle of a glass tube 1 cm. in diameter. The tube below the bulb is drawn out bent a t right angles and cemented on to a vitrosil tube 5 mm. in diameter with a bore of 1 mm. Three or four platinum wires 0.3 mm. diameter are placed within the pipe of vitrosil and constitute a wick extending out in a horizontal direction. The salt solutions when placed in the bulb are fed into the flame by capillary action along the platinum wires and the rate of introduction can be adequately controlled by varying the inclination of the tube. A Simple Automatic Apparatus €or Delivering Drops and Keeping a Constant Level in Washing with Acids. FRITZ REIMANN (Biochem. Z. 1922 133 112-113).-An apparatus is described on the syphon principle which delivers a slow current of liquid drop by drop a t a constant rate. W. E. G. W 0. K.