97 General and Physical Chemistry. Relation between the Composition and Absorption-spectra, of Organic Dyes. By H. W. VOGEL (Ber. Akad. Ber., 1887, 715- 718) .-Experiments made with azo-dyes gave the following results :- The substitution of methyl for hydrogen in diazobenzene gives rise t o change of position of the absorption-bands towards the red end of the spectrum. The increase of wave-length is 10 millionths mm. when the substitution takes place in the ortho-position, and 14 mil- lionths mm. in the case of the para-position. (2.) The substitution of p-naphtholsulphonic acid S or P-naph tholdisulphonic acid R for p-naphtholsulphonic acid B, causes a shifting of the ba8nds which, in the case of 6-naphtholsulphonic acid S amounts to 4 to 5 millionths mm., and in the case of p-naphtholdisulphonic acid R to 6 millionths mm.(3.) In the substitution of methyl, the space between the two bands becomes clearer, and the bands become more equal in intensity and in width. Tha substitution of p-naphtholsnlphonic acid S or 3-naph- tholdisulphonic acid R, in the place of the acid B, acts similarly on the character of the bands. The above results were obtained with sulphuric acid solutions ; the results, as well as those obtained with alcoholic solutions, are shown in tables. N. H. M. Fluorescences with Well-defined Spectra. By L. DE BOIS- BAUDRAN (Compt. rend., 105, 784- 788).-When gallium oxide is employed as a solid solvent of other oxides, it gives fluorescences which are usually much less brilliant than those obtained with alu- mina, but the results are of the same order.Calcination of t h e oxide at a very high temperature converts the bands in the spectrum into lines, the spectral groups being displaced towards the red. The bril- liancy of the spectrum increak- with the time of action of the electric discharge, a result contrary to that obtained with alumina. Measurements are gken of the spectra of the fluorescences of gallium oxide with oxides of samarium, Za and ZP. The fluorescence of Zp with gallium oxide is very feeble, the difference between Z~C and Zfl being even more strongly marked than when the oxides are mixed with alumina. A moderately calcined mixture of alumina with praseodymium oxide yields only a very faint trace of a rosy fluorescence, but if the mixture is very strongly heated, it then yields a beautiful fluorescence, the colour of which depends on the time during which the electric discharge has been passing.At first it is violet, but afterwards becomes rose-coloured. The spectrum is complicated, the principal bands, all of which are nebulous, being situated at 6457, 6237, 6162, 6035, and 5212. Rotatory Power of Solntions of Ammonium Molybdate and Tartaric Acid. By D. GERNEZ (Compt. rend., 105, 803-806).- VOL. LlV. h C. H. B.9 8 ABSTRACTS OF CHEMICAL PAPERS. The experiments previously made with solutions of tartaric acid and sodium molybdate (Abstr., 1887, 540) were repeated with ammonium molybdate. The rotatory power increases regularly as the quantity of ammonium molybdate increases, and is proportional to the quan- tity of this salt present up to a quarter of an eqnivalent.Between one-fourth and one-third of an equivalent, the increase of rotation for the same weight of malybdate changes suddenly, and beoomes little more than half its original value. The maximum rotation observed is 57 times that of tartaric acid, and corresponds with a proportion of ammonium mdybdate equal to one-t-hird of an equi- valent, it remains sensibly constant between 42.66/128 and 56/128 of an equivalent of molybdate. With large quantities, the rotatory power diminishes rapidly, and becomes practically constant when one equivalent of molybdate is present. As in. the case of sodium molybdate, the tartaric acid a t first com- bines with the whole of the ammonium molybdate, forming a com- pound of the composition 8C4Hti06 + 3(NH4),O, 7MoOs,4Hz0, which is gradually converted into a secand compound, containing 6 mnls.of tartario acid and 1 mol. of the molybdate, and this is finally trans- formed ink0 a third more stable compound, 2C4H6O6 + 3(NH4)2,0,7M00,4H20. In the caw of sodium molybdate, the maximum rotation is obtained with one equivalent of the salt, whilst i a the case of the ammonium rnolybdate, the maximum rotation is given by one-third of an equi- valent. The ammonium salt, however, contains three equivalents of the alkali in the molecule for eaoh equivalent present in the molecule of the sodium salt, and hence in each case the maximum rotation is given by compounds whioh contain the alkali and the tartaric acid in equal equivalents. C. H. B. Influenee of Light on the Heat Conductivity of Selenium.By N. BELLATI and S. LUSSANA( Gazzetta, 17,391-405).-The analogies of heat and electric conductivity induced bhe authors to study the influence of light an the heat conductivity of selenium, the electric resistarice of which, as is well known, is diminished on exposure. The plan of experiment consisted in sprinkling the double iodide of copper and mercury on the disc of selenium, on which a circular figure bad been blackened with Indian ink. Tbe selenium was heated by the passage of an electric current, which produced a t fir& a dark spof, owing ts the change in calour of the double iodide. Thib: sub- sequently extended into a fairly regular circular figure, the measure- ment of the diameter of whioh afforded a means of determining the heat conductivity of the selenium.This method was found ta be more practicable than the usual method of melting wax. I n all cases, the diameter of the circle was greater when the selenium was exposed to reflected sunlight from which the greniter part of the heat r a p had been removed by passage through solutious af alum and of nnimoniacal copper sulphate. The relation of heat conductivity without and with exposure to light was found to be in the ratio of 1 : 1.1 as the result of several concordant experiments. The sameGEKERAL AND PHYSJCAL CHEMISTRY. 99 ratio was observed between the electric conductivities without and with exposure to light under conditions similar to bhose describ-d above. The authors, however, would not insist on this concordance of results in the two phenomena. V.H. V. Effect of Light on the Conductivity of' Selenium. By S. KALTSCHER (Ann. Phys. Clbem. [2], 32, 108).--Uf the selenium cells constructed by the author, three in which copper and copper-brass electrodes are used, are found to differ from the rest in their behaviour on exposure to light, the resistance rapidly increasing after undergoing R momentary decrease, and the cell only returning to its normal condition on remaining for some time in tJhO dark. The conclusion drawn from this is, that the cells in question contain a hitherto uil- known modification of selenium, the conductivity of which decreases instead of increasing under the action of light. As the author's other cells which do not exhibit the peculiarity &scribed, differ from t,he a,bove in having zinc, copper-zinc, and copper-platinum electrodes.i t still remains 00 be ascertained whether the nature of the electrodes has any influence on this behavionr o€ selenium, The phenomenon in question has also been observed and described by Hesehus (Exn. Rep. d. Phys., 20, 490). H. C. New Galvanic Battery.. By F. FRIEDRICHS (Ann. Phys. Chetn. [2], 32,191) .-A tube running below the cells of this battery connects each with a cammon reservoir, by the raising or lowering of which the fluid used can be transmitted to or removed from t h e cells. A tap attanbed at the end of the tube opposhe the reservoir allows the fluid t o be removed when exhausted. An advantage claimed over other batteries is, that spontaneous evaporation of the liquid and consequent crystallisation of salts when the battery is not in use, is avoided.Galvanic Palarisation. By F. STRE~NTZ ( A m . Phys. Chew. [Z], 32, 116) ,-The author has examined the galvanic polarisation pro- duced on aluminium and silver plates. The results for aluminium have been already given (Abstr., 1887, 415). With silver, the oxygen plate is found Bo attain maximum polarisation when the E.M.F. of the cell used is equal to that of three Daniells ; the polarisation of the hydrogen plates is at a maximum when an E.M.F. of two Daniells is used, it decreases when a greater E.M.E. is employed, but rises again and becwmes equal to the first maximum for an E.M.F. of nine Daniells. The explanation given is that the deposition of metallic silver on the cathode, which is greater the greater the in- tensity of the ourrent, by increasing the surface decreases the relative strength of the current and amount of the polarisation, so that although a small E.M.F. produces maximum polarisation with clean plates, a very considerable one is required to attain the same maximum with plates thickly coated with silver.Production of Electricity by the Cmdensation of Aqueous Vapour. By L. PALMIER[ (Nuooo Cime?zto [3], 22, 3&39).-l'he occasion of this paper is the confirmation by Pirmin Larroque (La H. C. H. C. h 2100 ABSTRACTS OF CHEMICAL PAPERS. LzcmiZre $Zed., 1887) of the author's experiments on the production of electricity by the condensation of aqneous vaponr. On the other hand, the experiments of Kalischer (Abstr., 1884,138) led to negative results, but Tait considers that these were conducted on far too small a scale.Accordingly the author has repeated on a large scale his experiments on the condensation of aqueom vapour on a beaker of platizium containing ice, and connected with a condensing electric cup; in all cases, the production of electricity was observed. The iiithor remarks that his observations, extending over 37 years, leave no doubt in his mind as to the production of electricity under these conditions. The potential of atmospheric electricity is conditioned by the statme of the weather ; the author's observations also have more particularly shown that the potential is affected by the eruptions at Vesuvius. V. H. V. Electrolysis of Water. By H.v. HELMHOLTZ (Ber. Akad. Ber., 1887, 749--757).-Previous experiments made by the author showed that the smalIer the amount of dissolved hydrogen and oxygen near the electrodes, the smaller the electromotive force necessary to electrol yse water. The experiments described in the present paper were made with a v?ew to determine the limits for the smallest elec- tromotive force capable of producing fresh gas under a given pressure of the oxyhydrogen mixt,ure on the liquid. I n previous experiments, an error in the measurement of the electromotive € o m of the decom- position of water was caused by hydrogen or other combustible gas being occluded in the platinum anode (ir in both electrodes, so that the oxygen camied over in the current comes in contact with the gases of the modes, and thus bubbles of hydrogen will be liberated a t the cathodes with a much less expenditure of electromotive force.To avoid this, the current is kept in the same direction for weeks or months. An apparatus is described with sketch, by means of which the gases produced by the electrolysis are removed as soon as formed, and a vacuum is thus kept above the liquid ; the flask containing the solution is so inclined that a small bubble of gas is retained ; the gas under t'hese conditions occupies a space 1000 times greater than it would under normail pressme, and lfhe diameter of the bubble is measured in order to ascertain whether it remains the same size or whether it increases. To produae a current, three c a r h - i r o n ferric chloride solution elements were used ; the electromotive force was diminished daily in order to determine the limit.The limit for the evolution of gas was found to be 1-64 to 1-43 volt, wikh a pressure of oxyhydrogen gas = 10 mm. of water. The influence of pressure on elecfromotive force is expressed as follows :- A = A , + 1 0 - 7 . ~ . e { ~ ~ ~ i ~ g ~ ) 2ffh + ffo + yu = atmospheric pressure, p h andp, are the pressures of hydrogenGENERAL AND PHYSICAL CHEMISTRY. 101 and of oxygen above the liquid ; a h and a0 are the atomic weights of the two elements; 8 is the absolute temperature. where Vh is the volume of 1 gram of hydrogen ; R, the corresponding constant for oxygen, and 7 the amount of water decomposed in a second by one AmpAre. When pure oxyhydrogen gas is above the liquid, as in the experi- ments described, p = Ph + p,, the part of the electromotive force changing with the pressure becomes- 7 = 0.00009319 according to Kohlrausch.A, - A, = +. lO-’.v. 0 . Rh. log = 0.038868. log mat. ?‘). P2 N. H. 31. Electrolytic Separation of the Metal on the Free Surface of the Solution of its Salt. By J. GUBKIN (Ann. Phlp Chen~. [2j, 32, 114).-Wben an electric current passes from a solution of a salt into the atmosphere of gas or vapour immediately above it, an electrolytic separation of the metal takes place at the surface of the liquid. Apparatus is described by means o€ xhich this is made evident, the space above the liquid ‘being either vacuous or exposed to the air in the ordinary way. Silver and platinum are found to separate out in films which float on the surface ; zinc oxidises as it separates out, the white flakes of zinc oxide gradually falling to the bottom.H. C. Action of the Solvent on ElectroLytic Conduction. By T. C. FITZPATRICK (Phil. Mug. [ 5 ] , 24, 377-391).-The author continuer his researches om the conducti~it~y of salt solutions, the Bolvents being varied. The salts examined were calcium,. litbium, and magnesium chlorides asl;d nitrates, and ferric and mercuric chlorides, the solvents being water and ethyl and methyl alcohsls. Tables of conductivities are given. With mercuric chloride, which is the only salt mole soluble in alcohol than in water, the conductivihies are little more than those of the solvents alone. For aqueous solutions, the chlorides conduct better than the nitratcs ; magnesium chloride is anomdous, its conductivity being half that of calcium chloride.Ferric chloride i n dilute solution shows signs of dissociation. With alcoholic solu- tions, the conductivity is not proportional to the amount in solution. The conductivity of lithium salts in ethyl alcohol is 10 to 20 times as great as that of the other salts. I n all cases, the aqueous solutions conduct better than the alcoholic ones, the character of the solvent appearing to have an influence on the conductivity. This the author considers to be due to the formation of molecular groups in the solutions. He finds that the conductirity of salt solutions at low temperatures points to the existence in solution of cryobydrates a t temperatures above their solidifying points, and also that the con- ductivity of mixed solvents and of salts in mixed solvents differs from the calculated values, showing that an interaction has taken place with formation of new molecular gronps.The action then of the102 ABSTRACTS OY CHEMICAL PAPERS. solvent is twofold: (1) decomposition of the salt, the amount depend- ing on the temperatui-e, nature of solvent, and state of dilution ; (2) the formation of fresh molecular groups in the solution. Influence of a Magnetic Field on the Thermoelectric Pro- perties of Bismuth. BS G. P . GRIMALDI (Nuouo Cimento [3], 21, 57).-It is well known that n magnetic field influences in a remark- able degree the electric resistanw of bismuth; in this paper, the author shows that its thermoelectric force when paired with copper is varied in a similar degree.This pile was placed in the .field of an electromagnet, and coupled up with a galvanometer, in which read- ings were taken without and with a current passing round the electromagnet. After due allowance for induction, it is shown that the thermoelectric force of the bismuth-copper pair is materially decreased in the magnetic field. The experimental enquiry is, how- ever, only i n the preliminary stage. H. I(. T. V. H. V. Rotation of Isothermic Lines of Bismuth placed in a Magnetic Field. By A. RIGHI (Gazxetta, 17, 359).-In the course of experiments on the heat conductivity of bismuth when placed in a magnetic field, it was observed that the isothermic lines were rotated in a direction opposite to that of the magnetising current when a rectangular strip of the metal was placed with its planes normal to the line of force.The phenomenon is analogous to that observed by Hall, namely, the rotation a f the equipotential lines when a magnet acts on a current flowing along a thin strip of metal, and may explain the thermomagnetic currents recently discovered by Ettingshausen. v. H. v. Thermic Conductivity of Bismuth in a Magnetic Field. By A. RIGHI (Gazzetta, 17, 358--359).-The author, as well as other physicists, has observed the marked variation of the electric con- ductivity of bismuth when placed in a magnetic field (Abstr., 1887, ltO9), and the production of Hall's phenomenon under these con- di t ions. Considering the correlation of electric and thermic conduc- tivity, the effect of ningnetic field was also studied ; the results of the experiments showed Ithat with a field of 45?0 C.G.S.units the thermic conductivity of bismuth is to that of the metal under ordinary conditions as 2 : O-(U86. This result must at present be only con- sidered as approximate; further experiments are being niade with more refined apparatus. V. H. V. Specific Heat of Superfused Water. By P. CAEDAN~ and F. TOMAYINI (Nuovo Cimeuto 133, 21, 185).--The specific: heat of m t e r a t varims temperatmuyes has been the subject of numerous investiga- tions, although the results obtained are far from cnncoi*dant. Thus at temperatures 0-lo", Hirn, as also Pfaundler and Platter, has ob- served a marked increase of specific heat, whilst Rowland on the other hand observed a decrease.In this paper, a description is given of experiments made to determine the specific heat of water in t h e superfused condition. The method adopted in the investigation is practically an application of the weight thermometer; a knownGENERAL AND PHYSTOAL CHEMJSTKY. 103 volume of water is enclosed by mercury within 8 bulb, connected with which is a capillary tube bent twice at right angles. The whole apparatus is completely filled with water and mercury, and the bulb cooled by suitable freezing mixtures, then the mercury driven out by the expanding water is collected and weighed. The apparatus is then agitated, and the mercury driven out by the solidification of tthe water is also collected and weighed. Then from these data, together with a determination of the temperature at the moment of solidifica- tion, and the quantity of heat absorbed by the glass and the mercury contained, the specific heat of the water at the temperature of solidi- fication is ascertained. The various experimental errors are discussed in full, and the data of all the observations given in a series of tables.The following are the main conclusions : the specific heat of super- fused water is less than unity ; it increases with decrease of tempera- ture from a minimum at a temperature of -6.52" to 0". The final results are given below. Temperature. Specific heat. -652" to 0" 0953 --8*09 ,, 0 0.96 I -9.47 ,, 0 0.962 -10.67 ,, 0 0.985 V. H. V. New Form of Calorimeter. By W. I?. BARRETT (PTOC. R. Dublin Soc., 5, 13--16).-l'he instrument devised by the author is a modification of Bunsen's calorimeter.The cup for holding the sub- stance under experiment forms part of a mercurial thermometer. The cup has a capacity of 4 c.c., and is surrounded by a jacket of polished metal. The stem of the thermometer, of which the cup is a portion, is supported horizontally, and graduated from -5" to 80". Supported immediately above the cup is a small burette, the level of the liquid in which can be accurately read. The neck of the burette may be closed by a short thermometer graduated from 30" to 100". In making B determination of the specific heat of a liquid with this in- strument, the weight of the liquid must be found by taking its specific gravity for the temperature at which it was used ; the volume of the liquid used having been read from the bnrette.This inconvenience may be obviated by converting the thermometer into a balance, the fitem being supported by knife-edges somewhere near its centre of gravity. From the end of the stem, a pan is suspended, and beyond this a pointer, fixed to the stem, moves over a graduated arc. With a calorimeter balanced in this way, the weight of the liquid at a given air-temperature may be found directly. Determining the Specific Gravity of Small Quantities of Dense or Porous Substances. By J. JOLT ( P ~ o c . R. Dublin XOC., 5, 41-47).-The method generally employed for determining the specific gravity of small quantities of minerals of low density is by halancing in a liquid of known specific gravity. This method, however, is inapplicable when the substance has a specific gravity over 4, and also when the substance is of a porous nature.Under these conditions, the B. H. B.104 ABSTRACTS OF CHEMICAL PAPERS. substance may be mixed with another substance of much lower specific gravity in such proportion that the specific gravity of the mixed substances may be as close Go that of either of them as may be de- sired. FOP this purpose, t.he author uses the paraffin sold in the form of candles. The transparency of the paraffin enables the appearamce of the embedded mineral to be minutely examined. Results are given showing the accuracy of the method. B. H. B. Dissociation of Copper Sulphate. By W. M~~LLER-ERZBACH (Ann. Phys. Chem. [el, 32, 313). -The author has studied the dis- sociatiozl of copper sulphate at higher temperatures than those which he previously employed, and finds that his results agree with those obtained by Lesceur (Abstr., 1887, 208). The paper also contains a discussion of the dependence of chemical affinity on temperature (Abstr., 1887, 628).With sodium phosphate containing 5 mols. H,O, and sulphuric acid of 1.294 sp. gr., water passes from the acid to the salt at 32", but the changeis reversed, and water passes from the salt to the acid at 47". The equilibrium between the affinity of copper sulphate and of dilute sulphuric acid for water occurs, as might be expected, at higher temperatures the more dilute the acid. Rate of Dissociation as a Measure of the Vapour-tension of Hydrated Salts. By R. SCHULZE (Ann.Phys. Chew. [2], 32, 329). -A reply to Miiller-Erzbach. The author seeks to justify his former conclusions with regard to Muller-Erzbach's method of determining the vapour-tension of hydrated salts (Abstr., 1887, 766). Miiller- Erzbach having objected to the use of zinc sulphate as being a salt which admittedly exhibits irregularities in its bchayiour, copper sulphate is here shown to act in an irregular manner also when in- vestigated by the above method. In two out of three tubes contain- ing copper sulphate, evaporation set in at 20", but the third did not exhibit any change even at the end of 10 weeks. Interaction of Metals and Sulphuric Acid. By V. H. VELEY (Chew. News, 56, 221--222).-In this communication, the aut'hor points out that the results obtained by Spring and Aubin in their investigation on the action of acids on zinc containing lead (Abstr., 1887, 1074) do not adequately represent the Gate of chemical change as comparable, for example, with the rate of evolution of a gas from a homogeneous liquid.Thus the initial retardation or " induction " observed may be due to the adherence of bubbles of gas to the surface of the metal, and, eecondly, when the change has set in, the metal is surrounded by a concentrated solution of the metallic salt, which is ouly in part removed b r the gas bubbles. The hydrogen evolved is a resultant of a series of changes, each one of which is variable at any moment, such as the rate of diffusion of the salt of the metal in the acid liquid, the amount of surface exposed (which Spring and Aubin in some experiments kept approximately constant), and the local rise of temperature.The amount of gases other than hydrogen, such as sulphurous anhydride and hydrogen sulphide, is doubtless also dependent on the more or less perfect removal of the products of the H. C. H. C.QENERAL AND PHYSICAL CHEMISTRY. 105 change from the sphere of the dissolving metal as well as on the concentration of the acid solution. On the other hand, it does not seem that variations in the relative masses of zinc could make any difference either in the rate of solution or in the products of the change, provided that the surfaces exposed were equal. The dissolu- tion of a solid in a liquid must be regarded as R superficial action only. The author is at present studying the rate of solntion of metals in acid liquids under such conditions that not only fresh surfaces of a regular geometrical figure are continuously being exposed, but also the products of the change, whether gas or metallic salt, are at once and continuously removed from the vicinity of the dissolving rne tal.V. H. V. Velocity of the Formation of Ethereal Salts. By N. MEN- SCHUTKIN (Compt. rend., 105, 1016-1019) .--The particular reaction investigated was the action of acetic anhydride on alcohols, Ac,O + RHO = AcOR + AcOH, at 100". With most alcohols, the reaction is complete. The formation of the ethereal salt is accompaiiied by a, change of volume, which is least with methyl alcohol and increasingly greater with ethyl, propyl, and isobutyl alcohols. In order to eliminate this variable, the mixture of acetic anhydride and alcohol was diluted with 15 volumes of benzene.The constants of velocity are calculated from the equation - - = C(A - x) (B - x), in which A and B are the qnantities of the substances originally present, and x the quantity of the new substance formed in time t. A and B being equal, and ~t' and t being 0, --?-- = CAt, which gives the constant C. The results given in the following tables are the mean of several concordant ex- periments, the constants of' velocity being referred to that observed with methyl alcohol, which is taken as 100 :- dX dt A - - 0 Primary alcoliols. Methyl alcohol ............ Et,hyl ,, ............ Propyl 7, ............ Butyl 9 , ............ Isobutyl ,, ............ Octyl ), ,, ....0 cto decy 1 9 9 7 9 Melissy 1 ,7 9 , Hepttyl ,, (normal) .... Tetradecyl alcohol (normal). Hexadecyl ,, , J Ally1 9 , 7, a-Methyl ally1 alcohol ...... Benzyl alcohol ............ Constants of velocity. f--- 7 0-1053 100.0 0.0505 47.9 0.0480 4.506 0.0465 44.1 0.0401 38.1 0.0393 37.5 0.0377 315.8 0.0291 27-6 0.0269 25.5 0.0245 23.2 0.0174 16.5 0.0287 2 7.2 0-0267 25.3 0.0280 26.6106 ABSTRACTS OF CHEMICAL PAPERS. Constants of velocity. Secondary alcohols. r - 7 Isopropyl alcohol .......... 0.0148 14-1 Methyl ethyl carbinol ...... 0.0123 11.6 Methyl hexyl ,, ....... 0.0091 6 8.7 Methyl ally1 ,, ...... 0.00643 6.1 Trimethyl carbinol ......... 0.00091 0.8 Tertiary alcohol. The ethereal salts of the tertiary alcohols, phenols, and propargyl alcohol are decomposed by acetic acid, and hence in these cases the reactions are not comparable with those of primary alcohols.The greatest velocity is observed with methyl alcohol. The velocity is affected by the isomerism of the radicles in the alcohols, but is highest with primary alcohols, and much lower with secondary alcohols, whilst in the case of tertiaryaIcohols it is very small indeed. l n homologous alcohols of analogous constitution, the constant of velocity diminishes as the molecular weight increases, the difference being greatest in the normal primary alcohols. Non-saturated alcohols have a lower constant of velocity than the corresponding saturated alcohols, C. H. B.97General and Physical Chemistry.Relation between the Composition and Absorption-spectra,of Organic Dyes.By H. W. VOGEL (Ber. Akad. Ber., 1887, 715-718) .-Experiments made with azo-dyes gave the following results :-The substitution of methyl for hydrogen in diazobenzene gives riset o change of position of the absorption-bands towards the red end ofthe spectrum. The increase of wave-length is 10 millionths mm.when the substitution takes place in the ortho-position, and 14 mil-lionths mm. in the case of the para-position. (2.) The substitutionof p-naphtholsulphonic acid S or P-naph tholdisulphonic acid R forp-naphtholsulphonic acid B, causes a shifting of the ba8nds which, in thecase of 6-naphtholsulphonic acid S amounts to 4 to 5 millionths mm.,and in the case of p-naphtholdisulphonic acid R to 6 millionths mm.(3.) In the substitution of methyl, the space between the two bandsbecomes clearer, and the bands become more equal in intensity andin width.Tha substitution of p-naphtholsnlphonic acid S or 3-naph-tholdisulphonic acid R, in the place of the acid B, acts similarly onthe character of the bands.The above results were obtained with sulphuric acid solutions ;the results, as well as those obtained with alcoholic solutions, areshown in tables. N. H. M.Fluorescences with Well-defined Spectra. By L. DE BOIS-BAUDRAN (Compt. rend., 105, 784- 788).-When gallium oxide isemployed as a solid solvent of other oxides, it gives fluorescenceswhich are usually much less brilliant than those obtained with alu-mina, but the results are of the same order. Calcination of t h e oxideat a very high temperature converts the bands in the spectrum intolines, the spectral groups being displaced towards the red.The bril-liancy of the spectrum increak- with the time of action of the electricdischarge, a result contrary to that obtained with alumina.Measurements are gken of the spectra of the fluorescences ofgallium oxide with oxides of samarium, Za and ZP. The fluorescenceof Zp with gallium oxide is very feeble, the difference between Z~C andZfl being even more strongly marked than when the oxides are mixedwith alumina.A moderately calcined mixture of alumina with praseodymiumoxide yields only a very faint trace of a rosy fluorescence, but if themixture is very strongly heated, it then yields a beautiful fluorescence,the colour of which depends on the time during which the electricdischarge has been passing. At first it is violet, but afterwardsbecomes rose-coloured.The spectrum is complicated, the principalbands, all of which are nebulous, being situated at 6457, 6237,6162, 6035, and 5212.Rotatory Power of Solntions of Ammonium Molybdate andTartaric Acid. By D. GERNEZ (Compt. rend., 105, 803-806).-VOL. LlV. hC. H. B9 8 ABSTRACTS OF CHEMICAL PAPERS.The experiments previously made with solutions of tartaric acid andsodium molybdate (Abstr., 1887, 540) were repeated with ammoniummolybdate. The rotatory power increases regularly as the quantityof ammonium molybdate increases, and is proportional to the quan-tity of this salt present up to a quarter of an eqnivalent.Betweenone-fourth and one-third of an equivalent, the increase of rotationfor the same weight of malybdate changes suddenly, and beoomeslittle more than half its original value. The maximum rotationobserved is 57 times that of tartaric acid, and corresponds with aproportion of ammonium mdybdate equal to one-t-hird of an equi-valent, it remains sensibly constant between 42.66/128 and 56/128of an equivalent of molybdate. With large quantities, the rotatorypower diminishes rapidly, and becomes practically constant when oneequivalent of molybdate is present.As in. the case of sodium molybdate, the tartaric acid a t first com-bines with the whole of the ammonium molybdate, forming a com-pound of the composition 8C4Hti06 + 3(NH4),O, 7MoOs,4Hz0, whichis gradually converted into a secand compound, containing 6 mnls.of tartario acid and 1 mol.of the molybdate, and this is finally trans-formed ink0 a third more stable compound,2C4H6O6 + 3(NH4)2,0,7M00,4H20.In the caw of sodium molybdate, the maximum rotation is obtainedwith one equivalent of the salt, whilst i a the case of the ammoniumrnolybdate, the maximum rotation is given by one-third of an equi-valent. The ammonium salt, however, contains three equivalents ofthe alkali in the molecule for eaoh equivalent present in the moleculeof the sodium salt, and hence in each case the maximum rotation isgiven by compounds whioh contain the alkali and the tartaric acid inequal equivalents. C. H. B.Influenee of Light on the Heat Conductivity of Selenium.By N.BELLATI and S. LUSSANA( Gazzetta, 17,391-405).-The analogiesof heat and electric conductivity induced bhe authors to study theinfluence of light an the heat conductivity of selenium, the electricresistarice of which, as is well known, is diminished on exposure.The plan of experiment consisted in sprinkling the double iodide ofcopper and mercury on the disc of selenium, on which a circularfigure bad been blackened with Indian ink. Tbe selenium was heatedby the passage of an electric current, which produced a t fir& a darkspof, owing ts the change in calour of the double iodide. Thib: sub-sequently extended into a fairly regular circular figure, the measure-ment of the diameter of whioh afforded a means of determining theheat conductivity of the selenium.This method was found ta bemore practicable than the usual method of melting wax. I n all cases,the diameter of the circle was greater when the selenium was exposedto reflected sunlight from which the greniter part of the heat r a phad been removed by passage through solutious af alum and ofnnimoniacal copper sulphate. The relation of heat conductivitywithout and with exposure to light was found to be in the ratio of1 : 1.1 as the result of several concordant experiments. The samGEKERAL AND PHYSJCAL CHEMISTRY. 99ratio was observed between the electric conductivities without andwith exposure to light under conditions similar to bhose describ-dabove. The authors, however, would not insist on this concordance ofresults in the two phenomena. V.H. V.Effect of Light on the Conductivity of' Selenium. By S.KALTSCHER (Ann. Phys. Clbem. [2], 32, 108).--Uf the selenium cellsconstructed by the author, three in which copper and copper-brasselectrodes are used, are found to differ from the rest in their behaviouron exposure to light, the resistance rapidly increasing after undergoingR momentary decrease, and the cell only returning to its normalcondition on remaining for some time in tJhO dark. The conclusiondrawn from this is, that the cells in question contain a hitherto uil-known modification of selenium, the conductivity of which decreasesinstead of increasing under the action of light. As the author's othercells which do not exhibit the peculiarity &scribed, differ from t,hea,bove in having zinc, copper-zinc, and copper-platinum electrodes.i tstill remains 00 be ascertained whether the nature of the electrodeshas any influence on this behavionr o€ selenium, The phenomenonin question has also been observed and described by Hesehus (Exn.Rep. d. Phys., 20, 490). H. C.New Galvanic Battery.. By F. FRIEDRICHS (Ann. Phys. Chetn.[2], 32,191) .-A tube running below the cells of this battery connectseach with a cammon reservoir, by the raising or lowering of which thefluid used can be transmitted to or removed from t h e cells. A tapattanbed at the end of the tube opposhe the reservoir allows the fluidt o be removed when exhausted. An advantage claimed over otherbatteries is, that spontaneous evaporation of the liquid and consequentcrystallisation of salts when the battery is not in use, is avoided.Galvanic Palarisation.By F. STRE~NTZ ( A m . Phys. Chew. [Z],32, 116) ,-The author has examined the galvanic polarisation pro-duced on aluminium and silver plates. The results for aluminiumhave been already given (Abstr., 1887, 415). With silver, the oxygenplate is found Bo attain maximum polarisation when the E.M.F. ofthe cell used is equal to that of three Daniells ; the polarisation ofthe hydrogen plates is at a maximum when an E.M.F. of two Daniellsis used, it decreases when a greater E.M.E. is employed, but risesagain and becwmes equal to the first maximum for an E.M.F. ofnine Daniells. The explanation given is that the deposition ofmetallic silver on the cathode, which is greater the greater the in-tensity of the ourrent, by increasing the surface decreases the relativestrength of the current and amount of the polarisation, so thatalthough a small E.M.F.produces maximum polarisation with cleanplates, a very considerable one is required to attain the same maximumwith plates thickly coated with silver.Production of Electricity by the Cmdensation of AqueousVapour. By L. PALMIER[ (Nuooo Cime?zto [3], 22, 3&39).-l'heoccasion of this paper is the confirmation by Pirmin Larroque (LaH. C.H. C.h 100 ABSTRACTS OF CHEMICAL PAPERS.LzcmiZre $Zed., 1887) of the author's experiments on the productionof electricity by the condensation of aqneous vaponr.On the otherhand, the experiments of Kalischer (Abstr., 1884,138) led to negativeresults, but Tait considers that these were conducted on far too smalla scale. Accordingly the author has repeated on a large scale hisexperiments on the condensation of aqueom vapour on a beaker ofplatizium containing ice, and connected with a condensing electriccup; in all cases, the production of electricity was observed. Theiiithor remarks that his observations, extending over 37 years, leaveno doubt in his mind as to the production of electricity under theseconditions. The potential of atmospheric electricity is conditionedby the statme of the weather ; the author's observations also have moreparticularly shown that the potential is affected by the eruptions atVesuvius.V. H. V.Electrolysis of Water. By H. v. HELMHOLTZ (Ber. Akad. Ber.,1887, 749--757).-Previous experiments made by the author showedthat the smalIer the amount of dissolved hydrogen and oxygen nearthe electrodes, the smaller the electromotive force necessary toelectrol yse water. The experiments described in the present paperwere made with a v?ew to determine the limits for the smallest elec-tromotive force capable of producing fresh gas under a given pressureof the oxyhydrogen mixt,ure on the liquid. I n previous experiments,an error in the measurement of the electromotive € o m of the decom-position of water was caused by hydrogen or other combustible gasbeing occluded in the platinum anode (ir in both electrodes, so thatthe oxygen camied over in the current comes in contact with thegases of the modes, and thus bubbles of hydrogen will be liberated a tthe cathodes with a much less expenditure of electromotive force.To avoid this, the current is kept in the same direction for weeks ormonths.An apparatus is described with sketch, by means of whichthe gases produced by the electrolysis are removed as soon as formed,and a vacuum is thus kept above the liquid ; the flask containing thesolution is so inclined that a small bubble of gas is retained ; the gasunder t'hese conditions occupies a space 1000 times greater than itwould under normail pressme, and lfhe diameter of the bubble ismeasured in order to ascertain whether it remains the same size orwhether it increases.To produae a current, three c a r h - i r o n ferric chloride solutionelements were used ; the electromotive force was diminished daily inorder to determine the limit.The limit for the evolution of gas wasfound to be 1-64 to 1-43 volt, wikh a pressure of oxyhydrogen gas= 10 mm. of water.The influence of pressure on elecfromotive force is expressed asfollows :-A = A , + 1 0 - 7 . ~ . e { ~ ~ ~ i ~ g ~ ) 2ffh + ffo +yu = atmospheric pressure, p h andp, are the pressures of hydrogeGENERAL AND PHYSICAL CHEMISTRY. 101and of oxygen above the liquid ; a h and a0 are the atomic weights ofthe two elements; 8 is the absolute temperature.where Vh is the volume of 1 gram of hydrogen ; R, the correspondingconstant for oxygen, and 7 the amount of water decomposed in asecond by one AmpAre.When pure oxyhydrogen gas is above the liquid, as in the experi-ments described, p = Ph + p,, the part of the electromotive forcechanging with the pressure becomes-7 = 0.00009319 according to Kohlrausch.A, - A, = +.lO-’.v. 0 . Rh. log = 0.038868. log mat. ?‘). P2N. H. 31.Electrolytic Separation of the Metal on the Free Surface ofthe Solution of its Salt. By J. GUBKIN (Ann. Phlp Chen~. [2j,32, 114).-Wben an electric current passes from a solution of a saltinto the atmosphere of gas or vapour immediately above it, anelectrolytic separation of the metal takes place at the surface of theliquid. Apparatus is described by means o€ xhich this is madeevident, the space above the liquid ‘being either vacuous or exposed tothe air in the ordinary way.Silver and platinum are found toseparate out in films which float on the surface ; zinc oxidises as itseparates out, the white flakes of zinc oxide gradually falling to thebottom. H. C.Action of the Solvent on ElectroLytic Conduction. By T. C.FITZPATRICK (Phil. Mug. [ 5 ] , 24, 377-391).-The author continuerhis researches om the conducti~it~y of salt solutions, the Bolvents beingvaried. The salts examined were calcium,. litbium, and magnesiumchlorides asl;d nitrates, and ferric and mercuric chlorides, the solventsbeing water and ethyl and methyl alcohsls. Tables of conductivitiesare given. With mercuric chloride, which is the only salt molesoluble in alcohol than in water, the conductivihies are little morethan those of the solvents alone.For aqueous solutions, the chloridesconduct better than the nitratcs ; magnesium chloride is anomdous,its conductivity being half that of calcium chloride. Ferric chloridei n dilute solution shows signs of dissociation. With alcoholic solu-tions, the conductivity is not proportional to the amount in solution.The conductivity of lithium salts in ethyl alcohol is 10 to 20 timesas great as that of the other salts. I n all cases, the aqueous solutionsconduct better than the alcoholic ones, the character of the solventappearing to have an influence on the conductivity. This the authorconsiders to be due to the formation of molecular groups in thesolutions. He finds that the conductirity of salt solutions at lowtemperatures points to the existence in solution of cryobydrates a ttemperatures above their solidifying points, and also that the con-ductivity of mixed solvents and of salts in mixed solvents differs fromthe calculated values, showing that an interaction has taken placewith formation of new molecular gronps.The action then of th102 ABSTRACTS OY CHEMICAL PAPERS.solvent is twofold: (1) decomposition of the salt, the amount depend-ing on the temperatui-e, nature of solvent, and state of dilution ; (2)the formation of fresh molecular groups in the solution.Influence of a Magnetic Field on the Thermoelectric Pro-perties of Bismuth. BS G. P . GRIMALDI (Nuouo Cimento [3], 21,57).-It is well known that n magnetic field influences in a remark-able degree the electric resistanw of bismuth; in this paper, theauthor shows that its thermoelectric force when paired with copper isvaried in a similar degree.This pile was placed in the .field of anelectromagnet, and coupled up with a galvanometer, in which read-ings were taken without and with a current passing round theelectromagnet. After due allowance for induction, it is shown thatthe thermoelectric force of the bismuth-copper pair is materiallydecreased in the magnetic field. The experimental enquiry is, how-ever, only i n the preliminary stage.H. I(. T.V. H. V.Rotation of Isothermic Lines of Bismuth placed in aMagnetic Field. By A. RIGHI (Gazxetta, 17, 359).-In the courseof experiments on the heat conductivity of bismuth when placed in amagnetic field, it was observed that the isothermic lines were rotatedin a direction opposite to that of the magnetising current when arectangular strip of the metal was placed with its planes normal tothe line of force.The phenomenon is analogous to that observed byHall, namely, the rotation a f the equipotential lines when a magnetacts on a current flowing along a thin strip of metal, and may explainthe thermomagnetic currents recently discovered by Ettingshausen. v. H. v.Thermic Conductivity of Bismuth in a Magnetic Field. ByA. RIGHI (Gazzetta, 17, 358--359).-The author, as well as otherphysicists, has observed the marked variation of the electric con-ductivity of bismuth when placed in a magnetic field (Abstr., 1887,ltO9), and the production of Hall's phenomenon under these con-di t ions.Considering the correlation of electric and thermic conduc-tivity, the effect of ningnetic field was also studied ; the results of theexperiments showed Ithat with a field of 45?0 C.G.S. units the thermicconductivity of bismuth is to that of the metal under ordinaryconditions as 2 : O-(U86. This result must at present be only con-sidered as approximate; further experiments are being niade withmore refined apparatus. V. H. V.Specific Heat of Superfused Water. By P. CAEDAN~ and F.TOMAYINI (Nuovo Cimeuto 133, 21, 185).--The specific: heat of m t e ra t varims temperatmuyes has been the subject of numerous investiga-tions, although the results obtained are far from cnncoi*dant.Thusat temperatures 0-lo", Hirn, as also Pfaundler and Platter, has ob-served a marked increase of specific heat, whilst Rowland on theother hand observed a decrease. In this paper, a description isgiven of experiments made to determine the specific heat of water int h e superfused condition. The method adopted in the investigationis practically an application of the weight thermometer; a knowGENERAL AND PHYSTOAL CHEMJSTKY. 103volume of water is enclosed by mercury within 8 bulb, connectedwith which is a capillary tube bent twice at right angles. The wholeapparatus is completely filled with water and mercury, and the bulbcooled by suitable freezing mixtures, then the mercury driven out bythe expanding water is collected and weighed.The apparatus is thenagitated, and the mercury driven out by the solidification of tthewater is also collected and weighed. Then from these data, togetherwith a determination of the temperature at the moment of solidifica-tion, and the quantity of heat absorbed by the glass and the mercurycontained, the specific heat of the water at the temperature of solidi-fication is ascertained. The various experimental errors are discussedin full, and the data of all the observations given in a series of tables.The following are the main conclusions : the specific heat of super-fused water is less than unity ; it increases with decrease of tempera-ture from a minimum at a temperature of -6.52" to 0". The finalresults are given below.Temperature. Specific heat.-652" to 0" 0953--8*09 ,, 0 0.96 I-9.47 ,, 0 0.962-10.67 ,, 0 0.985V.H. V.New Form of Calorimeter. By W. I?. BARRETT (PTOC. R.Dublin Soc., 5, 13--16).-l'he instrument devised by the author is amodification of Bunsen's calorimeter. The cup for holding the sub-stance under experiment forms part of a mercurial thermometer. Thecup has a capacity of 4 c.c., and is surrounded by a jacket of polishedmetal. The stem of the thermometer, of which the cup is a portion,is supported horizontally, and graduated from -5" to 80". Supportedimmediately above the cup is a small burette, the level of the liquidin which can be accurately read. The neck of the burette may beclosed by a short thermometer graduated from 30" to 100".Inmaking B determination of the specific heat of a liquid with this in-strument, the weight of the liquid must be found by taking its specificgravity for the temperature at which it was used ; the volume of theliquid used having been read from the bnrette. This inconveniencemay be obviated by converting the thermometer into a balance, thefitem being supported by knife-edges somewhere near its centre ofgravity. From the end of the stem, a pan is suspended, and beyondthis a pointer, fixed to the stem, moves over a graduated arc. Witha calorimeter balanced in this way, the weight of the liquid at a givenair-temperature may be found directly.Determining the Specific Gravity of Small Quantities ofDense or Porous Substances. By J.JOLT ( P ~ o c . R. Dublin XOC.,5, 41-47).-The method generally employed for determining thespecific gravity of small quantities of minerals of low density is byhalancing in a liquid of known specific gravity. This method, however, isinapplicable when the substance has a specific gravity over 4, and alsowhen the substance is of a porous nature. Under these conditions, theB. H. B104 ABSTRACTS OF CHEMICAL PAPERS.substance may be mixed with another substance of much lower specificgravity in such proportion that the specific gravity of the mixedsubstances may be as close Go that of either of them as may be de-sired. FOP this purpose, t.he author uses the paraffin sold in the formof candles. The transparency of the paraffin enables the appearamceof the embedded mineral to be minutely examined.Results aregiven showing the accuracy of the method. B. H. B.Dissociation of Copper Sulphate. By W. M~~LLER-ERZBACH(Ann. Phys. Chem. [el, 32, 313). -The author has studied the dis-sociatiozl of copper sulphate at higher temperatures than those whichhe previously employed, and finds that his results agree with thoseobtained by Lesceur (Abstr., 1887, 208). The paper also contains adiscussion of the dependence of chemical affinity on temperature(Abstr., 1887, 628). With sodium phosphate containing 5 mols. H,O,and sulphuric acid of 1.294 sp. gr., water passes from the acid to thesalt at 32", but the changeis reversed, and water passes from the saltto the acid at 47". The equilibrium between the affinity of coppersulphate and of dilute sulphuric acid for water occurs, as might beexpected, at higher temperatures the more dilute the acid.Rate of Dissociation as a Measure of the Vapour-tension ofHydrated Salts.By R. SCHULZE (Ann. Phys. Chew. [2], 32, 329).-A reply to Miiller-Erzbach. The author seeks to justify his formerconclusions with regard to Muller-Erzbach's method of determiningthe vapour-tension of hydrated salts (Abstr., 1887, 766). Miiller-Erzbach having objected to the use of zinc sulphate as being a saltwhich admittedly exhibits irregularities in its bchayiour, coppersulphate is here shown to act in an irregular manner also when in-vestigated by the above method. In two out of three tubes contain-ing copper sulphate, evaporation set in at 20", but the third did notexhibit any change even at the end of 10 weeks.Interaction of Metals and Sulphuric Acid.By V. H. VELEY(Chew. News, 56, 221--222).-In this communication, the aut'horpoints out that the results obtained by Spring and Aubin in theirinvestigation on the action of acids on zinc containing lead (Abstr.,1887, 1074) do not adequately represent the Gate of chemicalchange as comparable, for example, with the rate of evolution of agas from a homogeneous liquid. Thus the initial retardation or" induction " observed may be due to the adherence of bubbles of gasto the surface of the metal, and, eecondly, when the change has set in,the metal is surrounded by a concentrated solution of the metallicsalt, which is ouly in part removed b r the gas bubbles.The hydrogenevolved is a resultant of a series of changes, each one of which isvariable at any moment, such as the rate of diffusion of the salt of themetal in the acid liquid, the amount of surface exposed (which Springand Aubin in some experiments kept approximately constant), and thelocal rise of temperature. The amount of gases other than hydrogen,such as sulphurous anhydride and hydrogen sulphide, is doubtless alsodependent on the more or less perfect removal of the products of theH. C.H. CQENERAL AND PHYSICAL CHEMISTRY. 105change from the sphere of the dissolving metal as well as on theconcentration of the acid solution. On the other hand, it does notseem that variations in the relative masses of zinc could make anydifference either in the rate of solution or in the products of thechange, provided that the surfaces exposed were equal.The dissolu-tion of a solid in a liquid must be regarded as R superficial actiononly. The author is at present studying the rate of solntion of metalsin acid liquids under such conditions that not only fresh surfaces of aregular geometrical figure are continuously being exposed, but alsothe products of the change, whether gas or metallic salt, are at onceand continuously removed from the vicinity of the dissolving rne tal.V. H. V.Velocity of the Formation of Ethereal Salts. By N. MEN-SCHUTKIN (Compt. rend., 105, 1016-1019) .--The particular reactioninvestigated was the action of acetic anhydride on alcohols, Ac,O +RHO = AcOR + AcOH, at 100". With most alcohols, the reactionis complete. The formation of the ethereal salt is accompaiiied by a,change of volume, which is least with methyl alcohol and increasinglygreater with ethyl, propyl, and isobutyl alcohols. In order to eliminatethis variable, the mixture of acetic anhydride and alcohol was dilutedwith 15 volumes of benzene. The constants of velocity are calculatedfrom the equation - - = C(A - x) (B - x), in which A and B are theqnantities of the substances originally present, and x the quantity ofthe new substance formed in time t. A and B being equal, and ~t' and tbeing 0, --?-- = CAt, which gives the constant C. The resultsgiven in the following tables are the mean of several concordant ex-periments, the constants of' velocity being referred to that observedwith methyl alcohol, which is taken as 100 :-dXdtA - - 0Primary alcoliols.Methyl alcohol ............Et,hyl ,, ............Propyl 7, ............Butyl 9 , ............Isobutyl ,, ............Octyl ), ,, ....0 cto decy 1 9 9 7 9Melissy 1 ,7 9 ,Hepttyl ,, (normal) ....Tetradecyl alcohol (normal).Hexadecyl ,, , JAlly1 9 , 7,a-Methyl ally1 alcohol ......Benzyl alcohol ............Constants of velocity.f--- 70-1053 100.00.0505 47.90.0480 4.5060.0465 44.10.0401 38.10.0393 37.50.0377 315.80.0291 27-60.0269 25.50.0245 23.20.0174 16.50.0287 2 7.20-0267 25.30.0280 26.106 ABSTRACTS OF CHEMICAL PAPERS.Constants of velocity.Secondary alcohols. r - 7Isopropyl alcohol .......... 0.0148 14-1Methyl ethyl carbinol ...... 0.0123 11.6Methyl hexyl ,, ....... 0.0091 6 8.7Methyl ally1 ,, ...... 0.00643 6.1Trimethyl carbinol ......... 0.00091 0.8Tertiary alcohol.The ethereal salts of the tertiary alcohols, phenols, and propargylalcohol are decomposed by acetic acid, and hence in these cases thereactions are not comparable with those of primary alcohols.The greatest velocity is observed with methyl alcohol. The velocityis affected by the isomerism of the radicles in the alcohols, but ishighest with primary alcohols, and much lower with secondaryalcohols, whilst in the case of tertiaryaIcohols it is very small indeed.l n homologous alcohols of analogous constitution, the constant ofvelocity diminishes as the molecular weight increases, the differencebeing greatest in the normal primary alcohols. Non-saturated alcoholshave a lower constant of velocity than the corresponding saturatedalcohols, C. H. B