J O U R N A L OF THE CHEMICAL SOCIETY, ABSTRACTS OF CHEMICAL PAPERS PUBLISHED IN BRITISH AND FOREIGN JOURNALS. General and P h y s i c a l Chemistry. Spectroscopic Examination of the Constituents of the Atrno- sphere. By J. JANSSEN (COW@. rend., 101, 649--651).-At the Meudon Observatory, four absorption tubes, one of which is 60 metres long, have been set up, and the absorption-spectra of hydrogen, air, and oxrgen have been examined, sometimes under high pressures. In the case of hydrogen, an enormous stratum of gas must be employed before any absorption-spectrum can be observed. When oxygen is examined in the 60-metre tube under pradudly increasing pressure, mccessive groups of lines appear. The first are the lines and bands in the red, which Egoroff regards as identical with the lines A and B in the solar spectrum, but if the pressure is raised beyond 27 atmos., and the intensity of the light employed is increased, evidences of absorption are obtained between A and B, and bettween B and C, but still higher pressures are necessary before the existence of absorption- bands in these positions can be definitely established.At rery high pressures, three other bands become visible, one in the red near OC, one in the greenish-yellow near D, and one in the blue. No similar bands are known in the solar spectrum. C. H. B. Optical Properties of Malic and Tartaric Acids. By L. BELL (Amer. Chem. J., 7, 120--128).-Both tartaric and malic acids show an increase oE optical activity with a rise in temperature, or with a decrease of concentration, and in the case of I ~ ~ ~ o - n ~ a l i c and dextro- tartaric acids, the sign of polarisation is reversed i f solutions suffi- ciently strong and cold are examined.From thermic observations it seetiis that this change of rotary power cannot be accounted for either by the supposition of changes of confignration of the molecule, or nf the formation of hydrates, or of the formation of crystal mole- cules. It is, however, thought that the change is due to the formn- tion of polymerides, which are gradually decomposed by dilution or VOL. L. b2 ABSTRACTS OF CHEMICAL PAPERS. application of heat ; in dilute solutions, the changes effected by rarin- tion are but slight when compared with those in strong solutions, where one must expect the polymeride to exist in comparatively large proportion.A further proof of the formation of polymerides is the fact that the solutions show abnormal rotary dispersion-a phenomenon not possible with the solution of a single substance-and this may be gradually made normal by dilution or by heating. Tartaric and malic acids both exist in more forms than can be accounted for on any existing theory; this may possibly be explained by the observation that two molecules of a substance containing an asymmetrical carbon-atom may be symmetrically united in four different ways. H. B. Sensitiveness t o Light of Selenium and Sulphur Cells. By S. BIDWELL (Chem. News, 52, 191--193).-With regard to the action of light in diminishing the electrical resistance of selenium, and pro- ducing in it a photo-electric current, Adams and Day have observed that in such mses the structure of the selenium is so modified that it behaves apparently like an electrolyte, and hence conclude that selenium, under those conditions, conducts electrolytically.I n the present paper, the author attributes these phenomena to actual electrolysis, and bases this assertion on the following facts. It is known that in making seleaium “ cells,” the longer they are “ annealed ” (that is, heated i n contact with the metallic electrodes) the more sensitive the selenium becomes to the action of light. Again, a very sensitive selenium “ cell ” has been constructed by Fritts, in the following manner :-A film of selenium is melted on R plate of metal with which it can combine, and ultimately the other surface is coated wit,h a transparent conductor.Moreover, a piece of selenium con- tained in a good “ cell ” with.copper electrodes indicated a specific resistance = 0.9 megohm, whilst the resistance of a similar piece of selenium annealed in a glass mould out of contact with metal = 2500 megohms. The author infers that a selenide is formed during the heating with the metal, and that the sensitiveness is due to the presence of the selenide and its electrolysis by the current. To complete the chain of experimental evidence, sulphur, which has hitherto resisted numerous attempts to develop in i t the sensitiveness to light so characteristic of selenium, was mixed with silver sol- phide, and incorporated in a “ cell ” with silver electrodes ; it then exhibited remarkable sensitiveness to light, and its resistance was greatly reduced by it.Numerous experiments are described proviiig this effect to be due to the direct action of radiation, and not simply t o R rise in the temperature, by which this sulphur “cell ” is affected jn a similar manner. Electrolytically considered, the action in the sulphur ‘‘ cell ” containing silver sulphide and silver electrodes is this : when the current passes, silver is deposited upon the cathode and sulphur upon the anode, but any sulphur deposited on the anode would stop the current, an occurrence which is prevented by the silver combining w i t h the sulphur, hence the quantity of electricity passing js regulated by the quantity of sulphur disposed of in this manner. By. replacing one of the silver electrodes by a metal which does riotGENERAL AND PHYSICAL CHEMISTRY.3 combine so readily with sulphur, iron for instance, then on the above hypothesis, when iron is the anode the resistance ought to be greater than when silver is the anode, and such is the case in actual experimcnt, the resistance being 30 times greater in the former than i t is in the latter case. Other experiments show that light assists the direct combination of silver and sulphur, and it is inferred that “the electrolysis of silver sulphide may be assisted by light, and its electrolytic resistance a t the same time diminished.” I n a few experiments made with sulphur “ cells ” containing copper and copper sulphide, there was no indication of sensitiveness to light.With regard to the effect of temperature on selenium “ cells,” the auhhor has observed that whether exposed to light or not, selenium “ cells ” have a temperature of maximum resistance, which is generally a few degrees higher than the average temperature of the air. D. A. L. Dry Electric Batteries. By W. v. BEETZ (Ann. Phys. Chem. [2], 26, 13--26).-This paper contains a series of determinations of the electromotive force of certain dry forms of Dnniell’s battery, especially of those consisting of U-tubes containing in the one limb copper sulphate solution, in the other zinc sulphate solution, both being xorked u p into a paste by plaster of Paris, and then allowed to set in the tnbes. Their use as an unit in electric measurements was examined ; it was found that in some cases the difference of poten- tial remained constant, whilst.in others i t decreased very rapidly. Such batteries cannot be used in electro-therapeutics. V. H. V. New Forms of Thermopiles. By H. KAPSER (Ann. Phys. Chem. [2], 26, 9--13).--In this paper, measurements are given of the electromotive forces and resistances of various forms of thermopiles, tlhe source of heat being a gas flame burning a known number of litres of gas per honr. The electromotive force of a NoG-Rebiceck’s thermoelectric pile of 20 elements was found to be constant, for an indefinite lengt,h of time, provided that the external conditions, namely, gas pressure and temperature of the air, were unaltered ; its electromotive force also exceeded that of a Bunsen’s element. The internal resistance increased to a maximum, with a consumption of gas from 0-60 litres per hour, and from that point to 110 litres per hour it diminished ; the maximum resistance of a pile of 25 elements was 0.868 ohm.The relative advantages of a thermopile over a, Bunsen’s element in cases of small external resistance are also dis- cussed. V. H. V. Electrical Conductivity of Air under Reduced Pressure. By T. HOMPN (Ann. Phys. Chenz. [ Z ] , 26, 55--81).-Experiments on the relation of the conductivity of air to the pressure, have led to the opposed conclusions that an absolute vacuum is a perfect non-con- ductor, and a good conductor of electricity. In this paper, an elabo- rate series of experiments on the conductivity of air in discharge tubes under various degrees of pressure are described.The results show that the phenomena of conductivity of air under reduced b 24 ABSTRACTS OF CHEMICAL PAPERS. pressure are of two kinds, the one, the particulw resistance of the air, which is proportional to the distance between the electrodes, the other the actual resistance of the electrodes themselves. The former i s independent of the diameter of the air column, and its increase is nearly proportional to the pressure, whilst the latter increases very quickly with decrease of pressure, and under low pressures reaches a point at which the resistance is such that electricity, even at the highest difference of potentiaJ, cannot overcome it, These results are not in accordance with the view that a vacuum is a good conductor of electricity. V.H. V. Electrical Conductivity of Alcohol. By E. PFEIFFER (Ann. Pliys. Chenz. [el, 26, 31-44).-1n this paper a description is given of determinations of the Conductivity of absolute alcohol, and the rnrintions produced by change of condition. The lowest value for recently distilled alcohol was 0.1261 x 10-10 ohms in ternis of mercury as the unit. The relative conductivity is increased by the presence of traces of impurities, but decreased to a considerable extent by the absorption of air.; it decreases, as that of metals, with rise of temperature, until a point is reached a t which the influence of temperature is nil. The author proposes to call this point ” the point of indifference.” Comparing the temperature coe5cient, or the ratio of decrease of conductivity, with r i s e of temperature = ?!! of alcohol with that of the mehals, it is found that the former is to the latter in the ratio 0*OG87 to 0.0037.V, H. V. k0 Electrical Properties of Salt Solutions. By J. MOSER (Xonatsh. Chem., 6, 634-638) .-The author has previously investi- gated the electromotive force of cells in which the total amount of purely chemical reacttion is reduced t o a minimum, the current being conditioned by the minor molecular attractions of a salt with the water in which it is dissolved ; such, for example, is the combination From these experi- ments Helmholtz determined the relation between the E.M.F., the vapour-tension of the salt solution, and the tmn+ference-uaZues of the ions (compare Faraday lecture, Trans., 1881, 299), so that if two of these values were known the third could be calculated.By the experi- mental elimination of the third factor, the relation could be determined between the E.M.F., conditioned by difference of concentration and the vapour-tension. Then, if the theories of Helmholtz are com- patible in the two cases stated above, the transference-value should be the quotient of the E.SLF.’s, with and without a possible transference of the ions. I n the paper this point is examined and found to be in accordance with the thtiory. There is also mentioned a case of electro-neutrality of a combina- tion Zn I ZnC1, I ZnSOi I Zn, in which the solutions were of .such a. degree of concentration thatj the addition of water to either of them produced a current with concomitant transference of the ions. Attention is also drawn to the fact that the E.M.F., produced by I Zn I dilute ZnSOa I concentrated ZnSOd I Zn.GENERAL AND PHYSICAL CHEMISTRY.n differences of concentration, does not correspond with the heat changes on dilution. V. H. V. Incandescence by Ultra-red Rays. By E. LOMMEL (Ann. Phys. Chew. [2], 26, 157--158).-After alluding to the experiments of Tyndall on the incandescence of p€atiiium by the impact of the ultra- red rays transmitted through a solution of iodine in carbon bisulphide, the author shows that t h e effects of these rays can be rendered visible by means of the so-called luminous paints, inasmuch as these rays are emitted as a greenish-blue fluorescence, A solution of nigrosin in chloroform or alcohol is proposed as a substitute for iodine in carbon bisulphide as a perfectly opaque but diathermic medium.V. H. V. So-called Specific Remission, By W, RAMSAY and S. YOUSG (Ber., 18, 2855-2858) .-The authors, after alluding to their various papers on the elation between the pressure and boiling points of liquids (compare Abstr., 1885, 629, Trans., 1885, 640-657) point out the im- probability of the relation designated by Kahlbaum “specific remission ” (Abstr., 1884, 141, 900), and the sources of error iii his method of investigation. The authors’ results for the vapour-tensions of ethyl alcohol are in accordance with t’hose of Regnault, although the former mere obtained by the dynamical, the latter by the startical method, hut those of Kahlbaum are widely divergent from both, a d are mesumablv worthless.I # L In the equation -- = !!f (in which L is the latent heat of the s1 - sz d t r vapour, s1 its volume, sz the volume of the liquid, 9 the increase of d t pressure for each degree temperature, t the absolute temperature, and T the heat equivalent of the work), the authors propose to show that the values for -- are approximately constant for several liquids, L 81 - sz and further, t,hat the ratio 3 for two substances A and R a t pre i- dt T sure p1 is equal to that for t,he same substances at different pre;- Fjure p2 : that-is- for A a t p l = !?!for A at p z . dt T dt T for B atpl= *! for R atp2. dt T dt T or expressed in terms of absolute temperature, 3 at pl = 3 atp,. T B TI3 A list of substances is given for which this relation is valid.V. H. V. Modification of Bunsen’s Ice Calorimeter. By A. RL~~MCKE (Ann. Phys. Ckem. [a], 26, 159--160).-Two forms of Bunsen’s ice calorimeter are used ; in the one the heat, change is measured by the change of position of a, mercury thread along a graduated scale, whilstr, ABSTRACTS OF CHEMlCAL PAPERS. in the other the instrument is made into an inverted weight ther- mometer. Both these methods have relative advantages and dis- advantages; the latter is more exact, but requires a longer time, wlrilst the former requires an inordinately long scale. I n this paper au instrument is described, by which determinations by both methods can be conducted simultaneously. The experimental tube is closed with a caoutchouc plug, through which pass two pieces of quill tubing, each bent a t right angles and provided with stop-cocks, the limb of the one being graduated, the limb of the other being bent again a t right angles, and dipping under the surface of a weighed quantity of it iercury.Then by opening or closing the stop-cocks determinations are made both by the scale and the inverted weight-thermometer met hods. V. H. V. Phenols. By BERTHELOP (Compt. rend., 101, 687--690).- C)rthocresoZ.-Heat of solution at 11.4" = - 2.08 cal.; heat of neutralisation by Boda, first equivalent + 7.79 cal., second half- equivalent + 0.4 cal. = + 8.19 cal. Paracresol.--Heat of solution at 11.4" = - 2.13 cal.; heat of neutralisa.tion b.y soda, first equivalent + 7.64 cal., second half- equivalent + 0.43 = + 8.27 cal. The values obtained are very similar in the case of each isomeride, and they agree closely with those obtained with phenol.ThyrrzoZ.-The specimen employed was obtained from oil of thyme, and had been crystallised for thirty years When dissolved in sodium hydroxide solution, the heat developed is + 5.73 cal., a number very similar to that obtained with solid phenol and the solid cresols under the same conditions. It follows, therefore, that the heats of solution and neutralisation of thymol are practically the same as those of its homologues. Recently fused or precipitated specimens of thymol give cliff erent and non-concordant results, because thyrnol, like chloral hydrate, parts very slowly with its heat of fusion. a-Naphthol.-Solution in one equivalent of sodium hydroxide solu- tion develops + 2.S4 cal., and the addition of a second equivalent of alkali develops + 0.2 citl., giving for the algebraic sum of the heats of solution and neutralisation the value + 3.04 cal.The corresponding values for 6-ncvphthol are + 2.19 cal. and + 0.00 cal. = + 2.19 cal. Quinhydrone (green quinone), CBH40z.C6H1(0H)2.-Heat of solution of quinone a t 13" = - 3-77 cal., Werner having previously found - 4-23 cal. The mean value is - 4.00 cal. Heat of solution of quinol at 13" = 4.155 cal. Concentrated solutions of the two com- pounds were mixed, the heat developed was measured, and the amount of quinbydrone which separated was determined. Froni these data the following values were calculated :- C6H,0, diss. + C,H,(oH), dim. = C,,H,,04 diss. + 0.50 C6H,02 ,, + C,H,(OH), ,, = Cr2H,,04 cryst.+ 17.2 CsH402 cryst. + c,H,(OH), cryst. = CI,HIOOI 9 , + 9.0 One part of quinhpdrone dissolves in 300 parts of water a t 14". No thermal disturbance is produced by the addition of an alkali to anthraquinone, phenanthraquinone, phlorone, and similar compounds,GESERAL AND PHYSICAL CHEXISTRY. 7 SO that, in this respect these compounds differ from the true quinones. They are more probably analogous to acetone, allylene oxide, and similar oxy-deriva tives of hydrocarbons. A l i z a r i n when dissolved in one equivalent of sodium hydroxide solution develops + 5.15 cal ; the addition of a second equivalent of alkali develops + 0.64 cal., whilst a tbird equivalent produces no thermal disturbance. It follows that in very dilute solutions alizarin shows only one phenolic function towards alkalis.I n this respect it resembles catechol, pyrogallol, and siniilar compounds of the ortho- series, and hence it would follow that alizarin also belongs to the same series. C. H. B. Isomerism in the Benzene Series: Phenols of Complex Function. By BERTHELOT (Compt. rend., 101, 651-6.56) .-Para- nzethoxybenzoic Acid (anisic acid), MeO*Cs H ,*CO OH.-Heat of solution i n an equivalent quantity of sodium hydroxide solution = + 5.125 cal. ; hence, assuming the heat of neutralisation to be the same as that of parahydroxybenzoic acid, + 13.0 cal., the heat of solution in water is - 7.9 cal. The addition of a second equivalent of alkali causes no sensible further development of heat; hence ariisic acid has no phenolic function.This agrees with the commonly accepted con- stitution of this acid. alethy1 rS'aZicylate, HO.C,H,*COOkfe.-Heat of solution in one equivalent of alkali + 4.0 cal., in a second equivalent + 0.20 cal. The first value will differ but little from the heat of neutralisation in an aqueous solution, since the solution of one liquid in another is never accompanied by any considerable absorption of heat. The heat of neuti-alisation of this ethereal salt is therefore comparable with that. of a phenol of weak function. Phenylglycollic Acid (mandelic acid): HO*CHPh*COOH.-Heat of solution a t 18" = - 3.09 cal. The addition of half an equivalent of alkali develops + 6.74 cal., a second half-equivalent + 6.88 cal., and a third half-equivalent + 0.34 cal. It is therefore a monobasic acid without any phenolic function.VanilZin, OH*C6H,(OMe)*CH0 [4 : 3 : 11.-Heat of solution at 13.7" = - 5.20 cal. The first equivalent of alkali develops + 9.26 cal., a second cquivalent produces no thermal disturbance. Methylproto- catechuic aldehyde therefore behaves as a monhydric phenol. VuniZZic Acid, OH*C6H:3(OMe).COOH [4 : 3 : 11.-Heat of solution at 13.9" = - 5.16. The first equivalent of alkali develops + 12.64 cal., the second + 9.74 cal., and the third + 1-37 cal. This acid, therefore, behaves as a monobasic acid and a monhydric phenol, as the ordinary formula indicates. Similar experiments show that piperonal (methyleneprotocatechuic aldehyde), piperonylic acid, pjperic acid, veratric acid, anisaldehyde, anisyl alcohol, anisoil, anethoil, and salicin have no phenolic function.The first equivalent of soda develops + 5.77 cal., the second + 0-86 cal., and the third produces no thermal disturbance. Tolueneparasulphonic acid and sodium benzenesulphonate have no phenolic function. Eugenol, on the other hand, behaves as a monhydric phenol.8 ABSTRACTS OF CHEMICAL PAPERS. I n all these cases, there is complete agreement between the thermo- chemical data and the generally accepted constitution of the corn- pounds as deduced from their chemical behaviour. Acids of the Benzene Series. By BERTHELOT (Compt. rend., 101, C. H. B. 685--686).--MeZlitic Acid, C,(COOH),.-Hed of solution = + 3%i2 cal. at 20.4"; it is therefore a positive quantity, and differs in this respect from the heats of solution of the majority of highly oxidised carbon acids.The heat of neutraliaaiion by successive equivalents of sodium oxide is as follows :- 9 , ,, + 14.70 ,, z= -+ 44.30. 9 , 9 9 ,, + 12.90 ,, = + 39.13. Third ,, 9 9 ,, + 14.80 ,, } 7, 1 First equivalent (&Na20) develops + 14.80 cal. Second ,, 97 Fourth ,, ,, + 13-60 ,, Sixth ,, ,, + 12-63 ,, Fifth The mean value is + 13.90 x 6 cal., which is almost exactly the same as that of benzoic and phthalic acids. The last three equivalents of alkali develop somewhat less heat than the first three, and in bhis respect also mellitic acid is analogous to phthalic acid. Meconic Acid, C,H,O, + 3H20.-Heat of neutralisation at 12.7" - - - '3.10 cal. the first, second, third, and fourth equivalents of alkali are respec- tively + 14.4 cal., + 13.6 cal., + 8.7 cal., + 0.7 cal., and from these results, which are analogous to those obtained by Louguinine wit'h phosphoric acid, it follows that meconic acid is really bibasic, with an accessory function which is either analogous to or identical with the phenolic function.Acrylacetic Acid (tetric acid), CbH,O,.-Heat of solution a t 12.7" = - 3.9 cal., heat of neutralisation + 12.5 cal. A second equivalent of alkali produces no sensible thermal disturbance, and therefore acrylacetic acid is a monobasic acid of Bimple function. It is worthy of note that the heat of neutralisation of very niany organic acids of very varied constitution differs but little from the value + 13 cal. The quantities of heat developed by the addition of C. H. B. Liquid Atmospheric Air.By S. v. WROBLEWSHI (Ann. Phys. (?hem. [2], 26, 134--144).--In many of its properties, atmospheric air resembles a, perfectly homogeneous gas, and on compression it appears to the superficial observer to behave as a single gas, so that its critical pressure and temperature have been determined. But in this paper it is shown that the liquefaction of air is accompanied by various complex phenomena, resembling those noticed in the com- pression of a mixture of five volumes of carbonic anhydride with one of air. Thus if atmospheric air is compressed until the meniscus first formed disappears, and the pressure allowed to decrease slowly, there are produced two superposed menisci, separating heterogeneous fluids, in which the relative propqrtion of oxygen and nitrogen is different, the lower fluid containing about 213 per cent., the upper 17.5-18-5 per cent.oxygen. Secondly, the tension curves of atmo-GENERAL AND PHYSICAL CHEJIISTRT. 9 spheric air are not regular, inasmuch as on compression the tem- perature a t first sinks uniformly in proportion t o decrease of pressure, urltil a minimum point a t - l Y 8 O is reached ; on further compression the temperature begins to rise to a maximum at - 19tj0, and thence decreases. These irregularities of the tension curves show that the two constitutents of the air are not vaporised equally, and the tem- perature observed is dependent on the momentary composition of the fluid. V. H. V. Variation of Temperature of Maximum Density of Water with Pressure. By G. P.GRIMALDI (Gazzetta, 15, 297-302)- Puschl and Van der Waals have shown that if the Coefficient of compressibility of water decreases with increase of temperature, then the temperature of the maximum density of any liquid must decrease with increase of pressure. This point has been experimentally ob- served by Marshall, Smith and Ormond, and Tait. The last-named agree in assigning a decrease of one degree temperature for every increase of fifty atmospheres, whilst Van der Wads assigns a decrease of 3.24" under the same conditions. In this paper, it is pointed out that this value of Van der Waals is probably incorrect, inasmuch as it is based on wrong data of the coefficient of compressibility obtained by Grassi. V. H. V. Do Crystals grow only by Juxtaposition of New Molecules ? By L.WULFF (Zeit. Kryst. Min., 10, 374--389).-From his experi- ments the author concludes that in some cases at least this question must be answered in the negative. Rate of Decomposition of Ozone. By E. MULDER (Rec. Trav. Chim., 4, 135--146).-1n continuation of his experiments with the ozonometer described in a previous paper (Rec. Trac. Chim., 3, 137-- 157), the autbor finds that the rate of decomposition of ozone, in a mixture of ozone and oxygen, a t a given temperature, is directly pro- portional to the number of ozone molecules present, and that this rate increases rapidly with the temperature. Contact Actions in Dissociation. By D. KONOWALOW (Bey., 18, 2808-2833).- Wurtz in the course of investigation on vapour-den- sities found that in the case of amyl bromide, the time taken for ihe determination, other conditions remaining the same, affected the result.In a recent paper, the author in conjunction with Menschutkin observed that the nature of the substances with which the vapour came in contact influenced the degree of dissociation (Abstr., 1884, l l l Y ) , the phenomenon being very marked with fine asbestos. In this paper, the contact effect of various subst'ances on the degree of dis- sociafion of various amyl compounds is more fully examined, a slightly modified form of V. Meyer's vapour-density apparatus being used. Thus the contact of finely divided silica caused 53 per cent. of the rapour of tertiary amyl acetate to be dissocialed at the end of 40 minutes. Amongst other substances, the following were found to be active in inducing this dissociation : silics, barium and calcium sul- phates, animal charcoal, freshly cleaned platinum foil, glass wool and A.P.10 ABSTRACTS OF CHEJIICAL PAPERS. glass powder from broken Rupert's drops. With amyl chloride, not only the pressure, &c., to which the vapour was subjected, but also the nature of the glass of the containing vessel, affected the degree of the dissociation. As regards the former, the collected results show that the velocity of the decomposition increases with increased pressure up t o a certain point, a t or above which it is independent of the pressure. As an explanation of this contact, action phenomenon, it is asked whether it is not possible that the bombardment of the molecules on the solid matter causes the kinetic energy of the molecules to be transformed in part into the internal work required for their decomposition.However this may be, these phenomena herein de- tailed are analogous to those observed in the experiments of Faraday and Dulong, on the effect of finely divided substances in inducing the combination of hydrogen with oxygen, and other chemical changes. In an added note, the author meets the criticisms of V. Meyer and Pond, and points out the reasons for the unsuccessful repetition of the experiments described by himself and Menschutkin. Decomposition of Carbon Compounds by the Electric Spark. By A. PIZZARELLO (Gazzettn, 15, 233-238).-1n this paper, a dcscrip- tion is given of the decomposition of the vapours of various carbon compounds introduced into a Torricellian vacuum and subjected to a series of electric sparks.Thus under these conditions a given volume of methyl alcohol is tripled, owing to its resolution into car- bonic oxide and hydrogen, thus : CH,*OH = CO + 2H2 ; the presence of both these gases was indicated. Similarly ethyl ether yields carbonic oxide, acetylene and hydrogen, together with carbon deposited on the platinum wires or walls of the tube, whilst ethyl formate gives water in addition to the above- mentioned products. V. H. V. Dissociation of Salts containing Water, and Conclusions drawn therefrom as to the Constitution of the Salts. By W. M~LLER-ERZRACH (Chem. Centr., 1885, 470).-A continuation of the author's experiments in which the vapour-tension of the water in the salt is compared with that of pure water (Abstr., 1885, 952).In tlhe present paper, the following salts are investigated :-MgS04 + 7H20, relative tension at 18 = 0.34, after loss of 1 mol. H,O, relative tension = 0.009; NiSO, + 7H20 = relative tension 0.56, became inappre- ciable after loss of 1 mol. H20 ; CoSOa + 7H20 gave similar results ; FeSO, + 7H20 gave different results, according to the method of crystallisation, the normal results seemed to be relative tension at 18.5 = 0.36 ; after loss of 3 mol. H,O, inappreciable. ZnSO, + 7H20, relative tension a t 19.5" = 0.43 ; after loss of 5 mol. H,O, this fell to 0%4-0*18, and was inappreciable when a salt containing 1$ mol. H,O was arrived at. Relative tension of CuSOa + 5H20 at 17" = 0*04-0-05; of CuSO, + 3H20 = about 0.02; after long exposure over solid potash, a salt with 1% mol.H,O was left. Relative tension of MnSOa + 5H,O = 0.50 ; of MnSO, + 1&H,O = 0.003 ; of MnS0, + 1% H,O = 0 : of CaC1, + 6H10 = 0 12; of CnC12 + 4H,9 = 0.08; of CaC1, + 2H20 = 0*013-0~01i ; of CaC12 + H2O = 0 : of CoClz + V. H. V.GENERAL AKD PHYSICAL CHEJIISTRY. 11 Propionic acid. 6H,O = 0.20; of CoCI, + 4H20 = 0: of MnCl, + 4H,O = 0.18; of MnC13 + 2H20 = 0 : of NaRr + 2H20 = 0.27: of BaCl, + 2H20 = 0.035; of BaClz + H,O = 0.097. The author calls attention t o the peculiar behaviour of some ~ a l t s , in which there is a t first no loss of water, the tension then gradually rises until it attains its maximum. A. J. G. Diffusion of Fatty Alcohols and Acids. By A. WISKELMANN (A7in.Phys. Chem. [ Z ] , 26, 10t5-134).-This paper is an extension of the author's researches on the diffusion of homologous ethereal salts (Abstr., 1885, lo), and contains an account of similar experi- ments with the paraffinojid alcohols and fatty acids. Observations with formic and acetic acids show that the observed reciprocal values of the molecular path-lengths are concordant with those calculated from the results of the ethereal salts; but in the case of the higher acids the calculated and observed values are not thus concordant. In the course of the research, it was noticed that in order to obtain comparable results, i t was necessary to determine the tension of the vapour and its diffusion with equal quantities of the liquid. The following table contains the diffusion coefficients and the mean path-lengths (I X 10') i n centimetres a t 0" and 760 mm.Butyric acid. Acetic acid. Air ................ Hydrogen .......... Carbonic anhydride . . Mean path-length .... -_--- I-- ---- 0.1061 0.404 0.0713 29'7 ~- 0.8847 0 * 3333 0 * 0595 227 ---- 0.068 0 * 2639 0 * 0476 166 0'1325 0 * 0994 0'0803 0.0688 0.06R1 0.0385 0'0589 0 -0499 Isobutjric acid. -- 0 * 0'704 0'2713 0 * 0472 171 --- 0.5001 0*088 0 * 3806 0.0693 0'3153 0.0577 0.2771 0 *0483 0.2716 0.0476 0.234 0.0419 0.2351 0'0422 0.1998 0-0351 IsovaIeric acid. -- 0.0555 0*2118 0-0375 124 --- Similar determinations were made with the paraffinoid alcohols, and the deduced mean path-lengths of the molecules show considerable variation in the case of the higher alcohols, but with the lower these differences are more constant.Below are given some of the reduced results, the upper number giving that for air, the middle that for hydrogen, and the lower that for carbonic anhydride. Alcohol. Met,hyl ............ Propjl ............ Isobutpl ........... Normal b rity 1 . ...... Ferinentat,iori amyl . . Normal amyl ....... Normal hexyl.. ..... Ethyl. ............. Diffusion coefficient. Mean path -length (1 x 108). 361 259 203 168 164 137 139 11112 ABSTRACTS OF CHEMICAL PAPERS. t = 10'. t = 20". P- ~ d. c. [.ID. d. c. [ n ] ~ . 7- - --- - - -- 60 p. c. .. 1.274563'725 + 5.92" 1.26'7063.350 + 7.36' 40 ,, .. 1*211348*460 '7.63 1.2065 $8'260 8-95 30 ,, . , 1 -1535 34 -605 9- 16 1 -1495 34 '485 10 -41 20 ,, . . 1.09'75 21 -950 10.89 1 *0045 d l -890 11.99 In conclusion, the results obtained for molecular path-lengths by this diffusion method are compared with those by Meyer and Schumann's transpiration method (Abstr., 1881, 504) ; the latter gives values nearly double as great as the former.It is, how- ever, shown that the tendency of the transpiration method is to give excessive results, and the apparent discrepancy is further cleared up by mathematical reasoning. By T. THOMSEN (J. pr. Chem. [2], 32, 211-230).-0f the large number of substances which are now known to rotate the plane of polarisation of a ray of polarised light, sugar has been by far the most fnlly inves- tigated. The optical activity of such substances is expressed as the speci,fic rotation [a], which is calculated from the formula [a] V.H. V. Conditions of Equilibrium in Aqueous Solutions. -- - a'100 where a = the observed rotation, I the length of liquid I , c ' examined, and c the concentration (expressed in grams of active substance in 100 c.c.) of that liquid. If the liquid is a pure substance, c becomes 100 d, where d = sp. gr. (density compared with water at &) ; but i f , as in the present case, the liquid is a solution of the active substance, c becomes p . d where p = the percentage of active a 100 substance in the sclution, and the formula becomes [a] = ;-- The author points out. the unfortunate looseness with which this formula is often used ( p being, for instance, often confounded with c ) , and the fact that the kind of light used is often not stated, so that many determinations published are practically useless.For cane-sugar the specific rotation has been found to be [a]= = + 66.5", and this value is correct within narrow limits, whatever the temperature or concentration of the solution employed. But in the case of most other optically active substances, the specific rotary power varies, and even sometimes changes in direction with change of temperature and concentration of solution. In the case of tartaric acid, the effect of heat and concentration is very marked, and, further, the rotation is increased between three and four fold by the neutralisa- tion of the acid with an alkali. The author has taken advantage of this sensitiveness of tartaric acid in investigating the conditions of equilibrium in mixed solutions.He has observed the rotary power of 50, 40, 30, and 20 per cent. solutions of tartaric acid at the tempe- ratures lo", 20", SO", with the following results :- 1.p.d' t = 30'. d. c. - --- 1*260063'000 + 8-63 1*201548*060 10-11 1.1460 34.380 11 -44 1.0905 21'810 12 *95GENERAL AND PHYSICAL CHEBZISTKT. 13 t 5 20°. For each temperature, the variation curve for different degrees of concentration between 20 and 50 per cent,. forms a straight line, and the following formula may therefore be deduced :- t = 25'. [.IF = 14.154 - 0.16&~1 = - 2.286 + 01644q. 50 p. (2.. . . 40 ,, ... 30 ,, ... 20 ,, ... I.]? =: 15.050 - 0.1535~ = - 0.300 + 0.1535~. 5.93" '7 -58 9'22 10.87 [a]?= 15.784 - 0.1429~ = + 1.494 + 0 1 4 2 9 ~ . 7 -38' 8.91 10 * 45 11.98 The second set of formula are obtained from the first bp taking p = 100 -q, where q = the percentage of water in the solution.It should be noticed, that whilst the variation for concentration, within the above limits, is constant. the increase of specific rotation for a given pise of temperatare diminishes with increasing temperature. Taking this into account and using the above formulae, the author has calmlated the following more complete table :- 8.03' 9.51 10.99 12.47 Spec& Rotation [a]= of Tartaric Acid. p . 1 t = 10". --I-- t = 15". 6-67' 8.26 9 -85 11 *44 I-- -- t = 30". --- 8 -64' 10.07 11-50 12 -93 [.IF= 14.615 - 0.158813 = - 1.265 + 0.1588q. These results lie between those obtained by Krecke (Arch. Ne'er- landaise, 7, 102) and those by Arndtsen (Ann. Chini. Phys. [ 3 ] , 54, 411).The author finds that a solution of tartaric acid (50 per cent.) may be kept for months withont undergoing any optical change. Determinations of the rotary power of varying mixtures of tartaric and citric acids and water, tartaric and acetic acids and water, and tartaric and sulphuric acids and water were made. The results obtained lead to the conclusion that the two acids present appropriate water in the proportion in which they aye present, or, in other words, that the solution consists of a mixture of solutions of the two acids of equal strength. Thus, for instance, if 30 grams tartaric acid and 20 grams citric acid are dissolved iii 50 grams water, the tartaric acid will appropriake 30 grams, the citric 20 grams of this water, and the specific rotation of the tartaric acid will be that of a 50 per cent.1 4 ABSTkACTS OF CHEMICAL PAPERS.solution. Tn the case of sulphuric acid and tartaric acid, the former appears to be present in the shape of its hexahydrate, HsSO,. These results seem to show that from such observations, it will be possible to determine the state of hydration in which various substdances exist in solution. L. T. T. Molecular Movements. By G. KRGSS (Ber., 18, 2586-2591).- Although the kinetic theory of gases gives some account of the trans- lation of molecules through space, yet no satisfactory hypothesis has been brought forward to illustrate either the rotation of the molecules about their own axes, or the interatomic movements within the mole- cules. These two last the author classifies under the title of ‘‘ inner molecular movements.” Prom the undulatory theory of light, deduc- tions can be drawn regarding these molecular movements, inas- much as the vibration of the ether, which fills the intramolecular s p c e , is conditioned within that space by the velocity and amplitude of the molecular vibrations. Thus if X be the wave-length of a ray emitted by a substance, v the velocity of light, the number of vibra- tions, n, which a molecule sends forth by rnovements of it as a whole and of its parts, can be determined by the equation n =: x’ The phenomena of emission and of absorption spectra thus throws Some light on the least and most extensive form of this inner molecular movement. I n this paper, this latter point is discussed, together with its relation to the interatomic attraction, which is conditioned by the chemical constitution of the molecule ; inasmuch as vibrations of the particles of a body are capable of being excited only by vibrations of a like period in the external ether, so from the wave-lengths of those rays of light, which are absorbed to the greatest degree by the solution of any substance, the numher of the vibrations of the mole- cules within the liquid can be calculated from the equation above. These positions of greatest absorption for derivatives of indigo and fluoresce’in have previously been determined by the author (Abstr., 1883, 1042), and from the observations, resiilts are obtained for the maximum number of vibrations for billionths of a second.In a table are given the results for indigo, its paraffino’id-, bromo-, nitro-, and amido-derivatives, for rosolic acid and its tetrabromo-derivative? and for fluorescein and its potassiom, bromo-, nitro-, and paraffino’id-derivatives.From the numbers given, it follows that the molecule of a com- pound emits fewer vibrations per second, the greater the number of hydrogen-atoms, or! in the case of analogous replacements of the hydrogen-atoms, the zncrease or dewease of molecular vibrations i s pro- portiond to the number of hydrogen-atoms thus replaced. The results are in accordance with those deduced by Kellstab from experiments v. H. v. on the transpirability of homologous compounds. Simple Burner for Monochromatic Light. By NOACK (Chem. Centr., 1885, 497-498) .-Consists of a hydrogen evolving apparatus, jnto the cork of which is inserted the stem of a Bunsen burner made of glass, and a wire for lowering or raising a block of metallic zinc.The salt for producing the required light is dissolved in the acid. J. K. C.INORGAVLC CHEJIISTRY, 15 An Aspirator. By A. GAwAr,ovsKI (Chern. Centr., 1885, 465).- A description of an aspirator, consisting of two vessels, revolving on an axis, and so constructed that it can be used as an aspirator or respirator. P. P. B. New Apparatus for Chemical Laboratories. By A. KALEC- SINSZEY (Chem. Centr., 1885, 545--546).-To expel sulphuric acid in the course of analysis, the author employs a wide glass tube sealed at the lower and upper extremities, the upper end being driven inwards to receive a platinum crucible fitted in with asbestos, and having a smdl open tube inserted laterally.Through this tube sulphiaric acid is passed into the apparatus ; the tube is connected with ,z suitable condenser, heat applied, and the liquid contents of the platinum crucible speedily evaporate. The author also describes a simple appa- ratus for obtaining an air blast by means of air and water dropping into a large flask. J. K. C. By C. M. STUART (Chew. News, 5 2, 208) .--9 modification of the glass hood described by Hempel (Ber., 18, 143i), so arranged as t o be placed on every working bench. A Gas Regulator constructed without Metal. By H. SCRIFF (Rer., 18, 2833-2841).-The arrangement cannot well be described without a figure. Improved Method of Ventilating Laboratories.J O U R N A LOFTHE CHEMICAL SOCIETY,ABSTRACTS OF CHEMICAL PAPERS PUBLISHED INBRITISH AND FOREIGN JOURNALS.General and P h y s i c a l Chemistry.Spectroscopic Examination of the Constituents of the Atrno-sphere.By J. JANSSEN (COW@. rend., 101, 649--651).-At theMeudon Observatory, four absorption tubes, one of which is 60 metreslong, have been set up, and the absorption-spectra of hydrogen, air,and oxrgen have been examined, sometimes under high pressures.In the case of hydrogen, an enormous stratum of gas must be employedbefore any absorption-spectrum can be observed. When oxygen isexamined in the 60-metre tube under pradudly increasing pressure,mccessive groups of lines appear. The first are the lines and bandsin the red, which Egoroff regards as identical with the lines A and Bin the solar spectrum, but if the pressure is raised beyond 27 atmos.,and the intensity of the light employed is increased, evidences ofabsorption are obtained between A and B, and bettween B and C, butstill higher pressures are necessary before the existence of absorption-bands in these positions can be definitely established.At rery highpressures, three other bands become visible, one in the red near OC, onein the greenish-yellow near D, and one in the blue. No similarbands are known in the solar spectrum. C. H. B.Optical Properties of Malic and Tartaric Acids. By L. BELL(Amer. Chem. J., 7, 120--128).-Both tartaric and malic acids showan increase oE optical activity with a rise in temperature, or with adecrease of concentration, and in the case of I ~ ~ ~ o - n ~ a l i c and dextro-tartaric acids, the sign of polarisation is reversed i f solutions suffi-ciently strong and cold are examined.From thermic observationsit seetiis that this change of rotary power cannot be accounted foreither by the supposition of changes of confignration of the molecule,or nf the formation of hydrates, or of the formation of crystal mole-cules. It is, however, thought that the change is due to the formn-tion of polymerides, which are gradually decomposed by dilution orVOL. L. 2 ABSTRACTS OF CHEMICAL PAPERS.application of heat ; in dilute solutions, the changes effected by rarin-tion are but slight when compared with those in strong solutions,where one must expect the polymeride to exist in comparatively largeproportion. A further proof of the formation of polymerides is the factthat the solutions show abnormal rotary dispersion-a phenomenonnot possible with the solution of a single substance-and this may begradually made normal by dilution or by heating.Tartaric and malic acids both exist in more forms than can beaccounted for on any existing theory; this may possibly be explainedby the observation that two molecules of a substance containing anasymmetrical carbon-atom may be symmetrically united in fourdifferent ways.H. B.Sensitiveness t o Light of Selenium and Sulphur Cells. ByS. BIDWELL (Chem. News, 52, 191--193).-With regard to the actionof light in diminishing the electrical resistance of selenium, and pro-ducing in it a photo-electric current, Adams and Day have observedthat in such mses the structure of the selenium is so modified that itbehaves apparently like an electrolyte, and hence conclude thatselenium, under those conditions, conducts electrolytically.I n the present paper, the author attributes these phenomena to actualelectrolysis, and bases this assertion on the following facts.It is known that in making seleaium “ cells,” the longer they are“ annealed ” (that is, heated i n contact with the metallic electrodes)the more sensitive the selenium becomes to the action of light.Again,a very sensitive selenium “ cell ” has been constructed by Fritts, in thefollowing manner :-A film of selenium is melted on R plate of metalwith which it can combine, and ultimately the other surface is coatedwit,h a transparent conductor.Moreover, a piece of selenium con-tained in a good “ cell ” with.copper electrodes indicated a specificresistance = 0.9 megohm, whilst the resistance of a similar piece ofselenium annealed in a glass mould out of contact with metal= 2500 megohms. The author infers that a selenide is formed duringthe heating with the metal, and that the sensitiveness is due to thepresence of the selenide and its electrolysis by the current. Tocomplete the chain of experimental evidence, sulphur, which hashitherto resisted numerous attempts to develop in i t the sensitivenessto light so characteristic of selenium, was mixed with silver sol-phide, and incorporated in a “ cell ” with silver electrodes ; it thenexhibited remarkable sensitiveness to light, and its resistance wasgreatly reduced by it.Numerous experiments are described proviiigthis effect to be due to the direct action of radiation, and not simplyt o R rise in the temperature, by which this sulphur “cell ” is affectedjn a similar manner. Electrolytically considered, the action in thesulphur ‘‘ cell ” containing silver sulphide and silver electrodes is this :when the current passes, silver is deposited upon the cathode andsulphur upon the anode, but any sulphur deposited on the anodewould stop the current, an occurrence which is prevented by the silvercombining w i t h the sulphur, hence the quantity of electricity passingjs regulated by the quantity of sulphur disposed of in this manner.By.replacing one of the silver electrodes by a metal which does rioGENERAL AND PHYSICAL CHEMISTRY. 3combine so readily with sulphur, iron for instance, then on theabove hypothesis, when iron is the anode the resistance ought tobe greater than when silver is the anode, and such is the case inactual experimcnt, the resistance being 30 times greater in theformer than i t is in the latter case. Other experiments show thatlight assists the direct combination of silver and sulphur, and it isinferred that “the electrolysis of silver sulphide may be assisted bylight, and its electrolytic resistance a t the same time diminished.”I n a few experiments made with sulphur “ cells ” containing copperand copper sulphide, there was no indication of sensitiveness to light.With regard to the effect of temperature on selenium “ cells,”the auhhor has observed that whether exposed to light or not,selenium “ cells ” have a temperature of maximum resistance, whichis generally a few degrees higher than the average temperature of theair.D. A. L.Dry Electric Batteries. By W. v. BEETZ (Ann. Phys. Chem. [2],26, 13--26).-This paper contains a series of determinations of theelectromotive force of certain dry forms of Dnniell’s battery,especially of those consisting of U-tubes containing in the one limbcopper sulphate solution, in the other zinc sulphate solution, bothbeing xorked u p into a paste by plaster of Paris, and then allowedto set in the tnbes.Their use as an unit in electric measurementswas examined ; it was found that in some cases the difference of poten-tial remained constant, whilst. in others i t decreased very rapidly.Such batteries cannot be used in electro-therapeutics.V. H. V.New Forms of Thermopiles. By H. KAPSER (Ann. Phys. Chem.[2], 26, 9--13).--In this paper, measurements are given of theelectromotive forces and resistances of various forms of thermopiles,tlhe source of heat being a gas flame burning a known number oflitres of gas per honr. The electromotive force of a NoG-Rebiceck’sthermoelectric pile of 20 elements was found to be constant, for anindefinite lengt,h of time, provided that the external conditions,namely, gas pressure and temperature of the air, were unaltered ; itselectromotive force also exceeded that of a Bunsen’s element.Theinternal resistance increased to a maximum, with a consumption ofgas from 0-60 litres per hour, and from that point to 110 litres perhour it diminished ; the maximum resistance of a pile of 25 elementswas 0.868 ohm. The relative advantages of a thermopile over a,Bunsen’s element in cases of small external resistance are also dis-cussed. V. H. V.Electrical Conductivity of Air under Reduced Pressure. By T. HOMPN (Ann. Phys. Chenz. [ Z ] , 26, 55--81).-Experiments on therelation of the conductivity of air to the pressure, have led to theopposed conclusions that an absolute vacuum is a perfect non-con-ductor, and a good conductor of electricity.In this paper, an elabo-rate series of experiments on the conductivity of air in dischargetubes under various degrees of pressure are described. The resultsshow that the phenomena of conductivity of air under reducedb 4 ABSTRACTS OF CHEMICAL PAPERS.pressure are of two kinds, the one, the particulw resistance of the air,which is proportional to the distance between the electrodes, theother the actual resistance of the electrodes themselves. The formeri s independent of the diameter of the air column, and its increase isnearly proportional to the pressure, whilst the latter increases veryquickly with decrease of pressure, and under low pressures reachesa point at which the resistance is such that electricity, even at thehighest difference of potentiaJ, cannot overcome it, These results arenot in accordance with the view that a vacuum is a good conductorof electricity. V.H. V.Electrical Conductivity of Alcohol. By E. PFEIFFER (Ann.Pliys. Chenz. [el, 26, 31-44).-1n this paper a description is givenof determinations of the Conductivity of absolute alcohol, and thernrintions produced by change of condition. The lowest value forrecently distilled alcohol was 0.1261 x 10-10 ohms in ternis ofmercury as the unit. The relative conductivity is increased by thepresence of traces of impurities, but decreased to a considerableextent by the absorption of air.; it decreases, as that of metals, withrise of temperature, until a point is reached a t which the influence oftemperature is nil.The author proposes to call this point ” the pointof indifference.” Comparing the temperature coe5cient, or the ratioof decrease of conductivity, with r i s e of temperature = ?!! of alcoholwith that of the mehals, it is found that the former is to the latter inthe ratio 0*OG87 to 0.0037. V, H. V.k0Electrical Properties of Salt Solutions. By J. MOSER(Xonatsh. Chem., 6, 634-638) .-The author has previously investi-gated the electromotive force of cells in which the total amount ofpurely chemical reacttion is reduced t o a minimum, the current beingconditioned by the minor molecular attractions of a salt with thewater in which it is dissolved ; such, for example, is the combinationFrom these experi-ments Helmholtz determined the relation between the E.M.F., thevapour-tension of the salt solution, and the tmn+ference-uaZues of theions (compare Faraday lecture, Trans., 1881, 299), so that if two ofthese values were known the third could be calculated. By the experi-mental elimination of the third factor, the relation could be determinedbetween the E.M.F., conditioned by difference of concentration andthe vapour-tension.Then, if the theories of Helmholtz are com-patible in the two cases stated above, the transference-value should bethe quotient of the E.SLF.’s, with and without a possible transferenceof the ions.I n the paper this point is examined and found to be in accordancewith the thtiory.There is also mentioned a case of electro-neutrality of a combina-tion Zn I ZnC1, I ZnSOi I Zn, in which the solutions were of .such a.degree of concentration thatj the addition of water to either of themproduced a current with concomitant transference of the ions.Attention is also drawn to the fact that the E.M.F., produced byI Zn I dilute ZnSOa I concentrated ZnSOd I ZnGENERAL AND PHYSICAL CHEMISTRY.ndifferences of concentration, does not correspond with the heat changeson dilution. V. H. V.Incandescence by Ultra-red Rays. By E. LOMMEL (Ann. Phys.Chew. [2], 26, 157--158).-After alluding to the experiments ofTyndall on the incandescence of p€atiiium by the impact of the ultra-red rays transmitted through a solution of iodine in carbon bisulphide,the author shows that t h e effects of these rays can be rendered visibleby means of the so-called luminous paints, inasmuch as these rays areemitted as a greenish-blue fluorescence, A solution of nigrosin inchloroform or alcohol is proposed as a substitute for iodine in carbonbisulphide as a perfectly opaque but diathermic medium.V.H. V.So-called Specific Remission, By W, RAMSAY and S. YOUSG(Ber., 18, 2855-2858) .-The authors, after alluding to their variouspapers on the elation between the pressure and boiling points of liquids(compare Abstr., 1885, 629, Trans., 1885, 640-657) point out the im-probability of the relation designated by Kahlbaum “specific remission ”(Abstr., 1884, 141, 900), and the sources of error iii his method ofinvestigation. The authors’ results for the vapour-tensions of ethylalcohol are in accordance with t’hose of Regnault, although theformer mere obtained by the dynamical, the latter by the starticalmethod, hut those of Kahlbaum are widely divergent from both, a dare mesumablv worthless.I # L In the equation -- = !!f (in which L is the latent heat of thes1 - sz d t rvapour, s1 its volume, sz the volume of the liquid, 9 the increase ofd tpressure for each degree temperature, t the absolute temperature, andT the heat equivalent of the work), the authors propose to show thatthe values for -- are approximately constant for several liquids, L81 - szand further, t,hat the ratio 3 for two substances A and R a t pre i- dt Tsure p1 is equal to that for t,he same substances at different pre;-Fjure p2 : that-is-for A a t p l = !?!for A at p z .dt T dt Tfor B atpl= *! for R atp2.dt T dt Tor expressed in terms of absolute temperature, 3 at pl = 3 atp,.T B TI3A list of substances is given for which this relation is valid.V.H. V.Modification of Bunsen’s Ice Calorimeter. By A. RL~~MCKE(Ann. Phys. Ckem. [a], 26, 159--160).-Two forms of Bunsen’s icecalorimeter are used ; in the one the heat, change is measured by thechange of position of a, mercury thread along a graduated scale, whilsr, ABSTRACTS OF CHEMlCAL PAPERS.in the other the instrument is made into an inverted weight ther-mometer. Both these methods have relative advantages and dis-advantages; the latter is more exact, but requires a longer time,wlrilst the former requires an inordinately long scale.I n this paperau instrument is described, by which determinations by both methodscan be conducted simultaneously. The experimental tube is closedwith a caoutchouc plug, through which pass two pieces of quill tubing,each bent a t right angles and provided with stop-cocks, the limb ofthe one being graduated, the limb of the other being bent again a tright angles, and dipping under the surface of a weighed quantity ofit iercury. Then by opening or closing the stop-cocks determinationsare made both by the scale and the inverted weight-thermometermet hods. V. H. V.Phenols. By BERTHELOP (Compt. rend., 101, 687--690).-C)rthocresoZ.-Heat of solution at 11.4" = - 2.08 cal.; heat ofneutralisation by Boda, first equivalent + 7.79 cal., second half-equivalent + 0.4 cal. = + 8.19 cal.Paracresol.--Heat of solution at 11.4" = - 2.13 cal.; heat ofneutralisa.tion b.y soda, first equivalent + 7.64 cal., second half-equivalent + 0.43 = + 8.27 cal.The values obtained are very similar in the case of each isomeride,and they agree closely with those obtained with phenol.ThyrrzoZ.-The specimen employed was obtained from oil of thyme,and had been crystallised for thirty years When dissolved in sodiumhydroxide solution, the heat developed is + 5.73 cal., a number verysimilar to that obtained with solid phenol and the solid cresols underthe same conditions.It follows, therefore, that the heats of solutionand neutralisation of thymol are practically the same as those of itshomologues. Recently fused or precipitated specimens of thymol givecliff erent and non-concordant results, because thyrnol, like chloralhydrate, parts very slowly with its heat of fusion.a-Naphthol.-Solution in one equivalent of sodium hydroxide solu-tion develops + 2.S4 cal., and the addition of a second equivalent ofalkali develops + 0.2 citl., giving for the algebraic sum of the heats ofsolution and neutralisation the value + 3.04 cal.The correspondingvalues for 6-ncvphthol are + 2.19 cal. and + 0.00 cal. = + 2.19 cal.Quinhydrone (green quinone), CBH40z.C6H1(0H)2.-Heat of solutionof quinone a t 13" = - 3-77 cal., Werner having previously found - 4-23 cal. The mean value is - 4.00 cal. Heat of solution ofquinol at 13" = 4.155 cal. Concentrated solutions of the two com-pounds were mixed, the heat developed was measured, and the amountof quinbydrone which separated was determined. Froni these datathe following values were calculated :-C6H,0, diss. + C,H,(oH), dim.= C,,H,,04 diss. + 0.50C6H,02 ,, + C,H,(OH), ,, = Cr2H,,04 cryst. + 17.2CsH402 cryst. + c,H,(OH), cryst. = CI,HIOOI 9 , + 9.0One part of quinhpdrone dissolves in 300 parts of water a t 14".No thermal disturbance is produced by the addition of an alkali toanthraquinone, phenanthraquinone, phlorone, and similar compoundsGESERAL AND PHYSICAL CHEXISTRY. 7SO that, in this respect these compounds differ from the true quinones.They are more probably analogous to acetone, allylene oxide, andsimilar oxy-deriva tives of hydrocarbons.A l i z a r i n when dissolved in one equivalent of sodium hydroxidesolution develops + 5.15 cal ; the addition of a second equivalent ofalkali develops + 0.64 cal., whilst a tbird equivalent produces nothermal disturbance.It follows that in very dilute solutions alizarinshows only one phenolic function towards alkalis. I n this respect itresembles catechol, pyrogallol, and siniilar compounds of the ortho-series, and hence it would follow that alizarin also belongs to thesame series. C. H. B.Isomerism in the Benzene Series: Phenols of ComplexFunction. By BERTHELOT (Compt. rend., 101, 651-6.56) .-Para-nzethoxybenzoic Acid (anisic acid), MeO*Cs H ,*CO OH.-Heat of solutioni n an equivalent quantity of sodium hydroxide solution = + 5.125 cal. ;hence, assuming the heat of neutralisation to be the same as that ofparahydroxybenzoic acid, + 13.0 cal., the heat of solution in water is - 7.9 cal.The addition of a second equivalent of alkali causesno sensible further development of heat; hence ariisic acid has nophenolic function. This agrees with the commonly accepted con-stitution of this acid.alethy1 rS'aZicylate, HO.C,H,*COOkfe.-Heat of solution in oneequivalent of alkali + 4.0 cal., in a second equivalent + 0.20 cal.The first value will differ but little from the heat of neutralisation inan aqueous solution, since the solution of one liquid in another isnever accompanied by any considerable absorption of heat. The heatof neuti-alisation of this ethereal salt is therefore comparable with that.of a phenol of weak function.Phenylglycollic Acid (mandelic acid): HO*CHPh*COOH.-Heat ofsolution a t 18" = - 3.09 cal.The addition of half an equivalent ofalkali develops + 6.74 cal., a second half-equivalent + 6.88 cal.,and a third half-equivalent + 0.34 cal. It is therefore a monobasicacid without any phenolic function.VanilZin, OH*C6H,(OMe)*CH0 [4 : 3 : 11.-Heat of solution at13.7" = - 5.20 cal. The first equivalent of alkali develops + 9.26 cal.,a second cquivalent produces no thermal disturbance. Methylproto-catechuic aldehyde therefore behaves as a monhydric phenol.VuniZZic Acid, OH*C6H:3(OMe).COOH [4 : 3 : 11.-Heat of solution at13.9" = - 5.16. The first equivalent of alkali develops + 12.64cal., the second + 9.74 cal., and the third + 1-37 cal.This acid,therefore, behaves as a monobasic acid and a monhydric phenol, asthe ordinary formula indicates.Similar experiments show that piperonal (methyleneprotocatechuicaldehyde), piperonylic acid, pjperic acid, veratric acid, anisaldehyde,anisyl alcohol, anisoil, anethoil, and salicin have no phenolic function.Thefirst equivalent of soda develops + 5.77 cal., the second + 0-86 cal.,and the third produces no thermal disturbance.Tolueneparasulphonic acid and sodium benzenesulphonate have nophenolic function.Eugenol, on the other hand, behaves as a monhydric phenol8 ABSTRACTS OF CHEMICAL PAPERS.I n all these cases, there is complete agreement between the thermo-chemical data and the generally accepted constitution of the corn-pounds as deduced from their chemical behaviour.Acids of the Benzene Series.By BERTHELOT (Compt. rend., 101,C. H. B.685--686).--MeZlitic Acid, C,(COOH),.-Hed of solution = + 3%i2cal. at 20.4"; it is therefore a positive quantity, and differs in thisrespect from the heats of solution of the majority of highly oxidisedcarbon acids. The heat of neutraliaaiion by successive equivalents ofsodium oxide is as follows :-9 , ,, + 14.70 ,, z= -+ 44.30.9 , 9 9 ,, + 12.90 ,, = + 39.13.Third ,, 9 9 ,, + 14.80 ,, }7, 1First equivalent (&Na20) develops + 14.80 cal.Second ,,97 Fourth ,, ,, + 13-60 ,,Sixth ,, ,, + 12-63 ,,FifthThe mean value is + 13.90 x 6 cal., which is almost exactly thesame as that of benzoic and phthalic acids. The last three equivalentsof alkali develop somewhat less heat than the first three, and in bhisrespect also mellitic acid is analogous to phthalic acid.Meconic Acid, C,H,O, + 3H20.-Heat of neutralisation at 12.7" - - - '3.10 cal.the first, second, third, and fourth equivalents of alkali are respec-tively + 14.4 cal., + 13.6 cal., + 8.7 cal., + 0.7 cal., and from theseresults, which are analogous to those obtained by Louguinine wit'hphosphoric acid, it follows that meconic acid is really bibasic, with anaccessory function which is either analogous to or identical with thephenolic function.Acrylacetic Acid (tetric acid), CbH,O,.-Heat of solution a t 12.7"= - 3.9 cal., heat of neutralisation + 12.5 cal.A second equivalentof alkali produces no sensible thermal disturbance, and thereforeacrylacetic acid is a monobasic acid of Bimple function.It is worthy of note that the heat of neutralisation of very nianyorganic acids of very varied constitution differs but little from thevalue + 13 cal.The quantities of heat developed by the addition ofC. H.B.Liquid Atmospheric Air. By S. v. WROBLEWSHI (Ann. Phys.(?hem. [2], 26, 134--144).--In many of its properties, atmosphericair resembles a, perfectly homogeneous gas, and on compression itappears to the superficial observer to behave as a single gas, so thatits critical pressure and temperature have been determined. But inthis paper it is shown that the liquefaction of air is accompanied byvarious complex phenomena, resembling those noticed in the com-pression of a mixture of five volumes of carbonic anhydride with oneof air.Thus if atmospheric air is compressed until the meniscusfirst formed disappears, and the pressure allowed to decrease slowly,there are produced two superposed menisci, separating heterogeneousfluids, in which the relative propqrtion of oxygen and nitrogen isdifferent, the lower fluid containing about 213 per cent., the upper17.5-18-5 per cent. oxygen. Secondly, the tension curves of atmoGENERAL AND PHYSICAL CHEJIISTRT. 9spheric air are not regular, inasmuch as on compression the tem-perature a t first sinks uniformly in proportion t o decrease of pressure,urltil a minimum point a t - l Y 8 O is reached ; on further compressionthe temperature begins to rise to a maximum at - 19tj0, and thencedecreases.These irregularities of the tension curves show that thetwo constitutents of the air are not vaporised equally, and the tem-perature observed is dependent on the momentary composition ofthe fluid. V. H. V.Variation of Temperature of Maximum Density of Waterwith Pressure. By G. P. GRIMALDI (Gazzetta, 15, 297-302)-Puschl and Van der Waals have shown that if the Coefficient ofcompressibility of water decreases with increase of temperature, thenthe temperature of the maximum density of any liquid must decreasewith increase of pressure. This point has been experimentally ob-served by Marshall, Smith and Ormond, and Tait. The last-namedagree in assigning a decrease of one degree temperature for everyincrease of fifty atmospheres, whilst Van der Wads assigns a decreaseof 3.24" under the same conditions.In this paper, it is pointed outthat this value of Van der Waals is probably incorrect, inasmuch asit is based on wrong data of the coefficient of compressibility obtainedby Grassi. V. H. V.Do Crystals grow only by Juxtaposition of New Molecules ?By L. WULFF (Zeit. Kryst. Min., 10, 374--389).-From his experi-ments the author concludes that in some cases at least this questionmust be answered in the negative.Rate of Decomposition of Ozone. By E. MULDER (Rec. Trav.Chim., 4, 135--146).-1n continuation of his experiments with theozonometer described in a previous paper (Rec. Trac. Chim., 3, 137--157), the autbor finds that the rate of decomposition of ozone, in amixture of ozone and oxygen, a t a given temperature, is directly pro-portional to the number of ozone molecules present, and that this rateincreases rapidly with the temperature.Contact Actions in Dissociation.By D. KONOWALOW (Bey., 18,2808-2833).- Wurtz in the course of investigation on vapour-den-sities found that in the case of amyl bromide, the time taken for ihedetermination, other conditions remaining the same, affected theresult. In a recent paper, the author in conjunction with Menschutkinobserved that the nature of the substances with which the vapourcame in contact influenced the degree of dissociation (Abstr., 1884,l l l Y ) , the phenomenon being very marked with fine asbestos. Inthis paper, the contact effect of various subst'ances on the degree of dis-sociafion of various amyl compounds is more fully examined, a slightlymodified form of V.Meyer's vapour-density apparatus being used.Thus the contact of finely divided silica caused 53 per cent. of therapour of tertiary amyl acetate to be dissocialed at the end of 40minutes. Amongst other substances, the following were found to beactive in inducing this dissociation : silics, barium and calcium sul-phates, animal charcoal, freshly cleaned platinum foil, glass wool andA. P10 ABSTRACTS OF CHEJIICAL PAPERS.glass powder from broken Rupert's drops. With amyl chloride, notonly the pressure, &c., to which the vapour was subjected, but also thenature of the glass of the containing vessel, affected the degree of thedissociation. As regards the former, the collected results show thatthe velocity of the decomposition increases with increased pressure upt o a certain point, a t or above which it is independent of the pressure.As an explanation of this contact, action phenomenon, it is askedwhether it is not possible that the bombardment of the moleculeson the solid matter causes the kinetic energy of the molecules tobe transformed in part into the internal work required for theirdecomposition. However this may be, these phenomena herein de-tailed are analogous to those observed in the experiments of Faradayand Dulong, on the effect of finely divided substances in inducing thecombination of hydrogen with oxygen, and other chemical changes.In an added note, the author meets the criticisms of V.Meyer andPond, and points out the reasons for the unsuccessful repetition ofthe experiments described by himself and Menschutkin.Decomposition of Carbon Compounds by the Electric Spark.By A. PIZZARELLO (Gazzettn, 15, 233-238).-1n this paper, a dcscrip-tion is given of the decomposition of the vapours of various carboncompounds introduced into a Torricellian vacuum and subjected toa series of electric sparks. Thus under these conditions a givenvolume of methyl alcohol is tripled, owing to its resolution into car-bonic oxide and hydrogen, thus : CH,*OH = CO + 2H2 ; the presenceof both these gases was indicated.Similarly ethyl ether yields carbonic oxide, acetylene and hydrogen,together with carbon deposited on the platinum wires or walls of thetube, whilst ethyl formate gives water in addition to the above-mentioned products.V. H. V.Dissociation of Salts containing Water, and Conclusionsdrawn therefrom as to the Constitution of the Salts. By W.M~LLER-ERZRACH (Chem. Centr., 1885, 470).-A continuation of theauthor's experiments in which the vapour-tension of the water in thesalt is compared with that of pure water (Abstr., 1885, 952). In tlhepresent paper, the following salts are investigated :-MgS04 + 7H20,relative tension at 18 = 0.34, after loss of 1 mol. H,O, relative tension= 0.009; NiSO, + 7H20 = relative tension 0.56, became inappre-ciable after loss of 1 mol. H20 ; CoSOa + 7H20 gave similar results ;FeSO, + 7H20 gave different results, according to the method ofcrystallisation, the normal results seemed to be relative tension at18.5 = 0.36 ; after loss of 3 mol.H,O, inappreciable. ZnSO, + 7H20,relative tension a t 19.5" = 0.43 ; after loss of 5 mol. H,O, this fell to0%4-0*18, and was inappreciable when a salt containing 1$ mol.H,O was arrived at. Relative tension of CuSOa + 5H20 at 17" =0*04-0-05; of CuSO, + 3H20 = about 0.02; after long exposureover solid potash, a salt with 1% mol. H,O was left. Relative tensionof MnSOa + 5H,O = 0.50 ; of MnSO, + 1&H,O = 0.003 ; of MnS0, +1% H,O = 0 : of CaC1, + 6H10 = 0 12; of CnC12 + 4H,9 = 0.08;of CaC1, + 2H20 = 0*013-0~01i ; of CaC12 + H2O = 0 : of CoClz +V. H. VGENERAL AKD PHYSICAL CHEJIISTRY.11Propionicacid.6H,O = 0.20; of CoCI, + 4H20 = 0: of MnCl, + 4H,O = 0.18; ofMnC13 + 2H20 = 0 : of NaRr + 2H20 = 0.27: of BaCl, + 2H20 =0.035; of BaClz + H,O = 0.097. The author calls attention t o thepeculiar behaviour of some ~ a l t s , in which there is a t first no loss ofwater, the tension then gradually rises until it attains its maximum.A. J. G.Diffusion of Fatty Alcohols and Acids. By A. WISKELMANN(A7in. Phys. Chem. [ Z ] , 26, 10t5-134).-This paper is an extensionof the author's researches on the diffusion of homologous etherealsalts (Abstr., 1885, lo), and contains an account of similar experi-ments with the paraffinojid alcohols and fatty acids. Observationswith formic and acetic acids show that the observed reciprocal valuesof the molecular path-lengths are concordant with those calculatedfrom the results of the ethereal salts; but in the case of the higheracids the calculated and observed values are not thus concordant.Inthe course of the research, it was noticed that in order to obtaincomparable results, i t was necessary to determine the tension of thevapour and its diffusion with equal quantities of the liquid.The following table contains the diffusion coefficients and the meanpath-lengths (I X 10') i n centimetres a t 0" and 760 mm.Butyricacid.Aceticacid.Air ................Hydrogen ..........Carbonic anhydride . .Mean path-length ....-_---I-- ----0.10610.4040.071329'7~-0.88470 * 33330 * 0595227----0.0680 * 26390 * 04761660'13250 * 09940'08030.06880.06R10.03850'05890 -0499Isobutjricacid.--0 * 0'7040'27130 * 0472171---0.5001 0*0880 * 3806 0.06930'3153 0.05770.2771 0 *04830.2716 0.04760.234 0.04190.2351 0'04220.1998 0-0351IsovaIericacid.--0.05550*21180-0375124---Similar determinations were made with the paraffinoid alcohols,and the deduced mean path-lengths of the molecules show considerablevariation in the case of the higher alcohols, but with the lower thesedifferences are more constant. Below are given some of the reducedresults, the upper number giving that for air, the middle that forhydrogen, and the lower that for carbonic anhydride.Alcohol.Met,hyl ............Propjl ............Isobutpl ...........Normal b rity 1 .......Ferinentat,iori amyl . .Normal amyl .......Normal hexyl.. .....Ethyl. .............Diffusion coefficient.Mean path -length(1 x 108).3612592031681641371391112 ABSTRACTS OF CHEMICAL PAPERS.t = 10'. t = 20".P- ~d. c. [.ID. d. c. [ n ] ~ .7- - --- - - --60 p. c. .. 1.274563'725 + 5.92" 1.26'7063.350 + 7.36'40 ,, .. 1*211348*460 '7.63 1.2065 $8'260 8-9530 ,, . , 1 -1535 34 -605 9- 16 1 -1495 34 '485 10 -4120 ,, . . 1.09'75 21 -950 10.89 1 *0045 d l -890 11.99In conclusion, the results obtained for molecular path-lengthsby this diffusion method are compared with those by Meyer andSchumann's transpiration method (Abstr., 1881, 504) ; the lattergives values nearly double as great as the former. It is, how-ever, shown that the tendency of the transpiration method is to giveexcessive results, and the apparent discrepancy is further cleared upby mathematical reasoning.By T.THOMSEN (J.pr. Chem. [2], 32, 211-230).-0f the large number ofsubstances which are now known to rotate the plane of polarisationof a ray of polarised light, sugar has been by far the most fnlly inves-tigated. The optical activity of such substances is expressed asthe speci,fic rotation [a], which is calculated from the formula [a]V. H. V.Conditions of Equilibrium in Aqueous Solutions.-- - a'100 where a = the observed rotation, I the length of liquidI , c 'examined, and c the concentration (expressed in grams of activesubstance in 100 c.c.) of that liquid.If the liquid is a pure substance,c becomes 100 d, where d = sp. gr. (density compared with waterat &) ; but i f , as in the present case, the liquid is a solution of theactive substance, c becomes p . d where p = the percentage of activea 100 substance in the sclution, and the formula becomes [a] = ;--The author points out. the unfortunate looseness with which thisformula is often used ( p being, for instance, often confounded with c ) ,and the fact that the kind of light used is often not stated, so thatmany determinations published are practically useless.For cane-sugar the specific rotation has been found to be [a]== + 66.5", and this value is correct within narrow limits, whateverthe temperature or concentration of the solution employed.But inthe case of most other optically active substances, the specific rotarypower varies, and even sometimes changes in direction with changeof temperature and concentration of solution. In the case of tartaricacid, the effect of heat and concentration is very marked, and, further,the rotation is increased between three and four fold by the neutralisa-tion of the acid with an alkali. The author has taken advantage ofthis sensitiveness of tartaric acid in investigating the conditions ofequilibrium in mixed solutions. He has observed the rotary power of50, 40, 30, and 20 per cent. solutions of tartaric acid at the tempe-ratures lo", 20", SO", with the following results :-1.p.d't = 30'.d. c. - ---1*260063'000 + 8-631*201548*060 10-111.1460 34.380 11 -441.0905 21'810 12 *9GENERAL AND PHYSICAL CHEBZISTKT.13t 5 20°.For each temperature, the variation curve for different degrees ofconcentration between 20 and 50 per cent,. forms a straight line, andthe following formula may therefore be deduced :-t = 25'.[.IF = 14.154 - 0.16&~1 = - 2.286 + 01644q.50 p. (2.. . .40 ,, ...30 ,, ...20 ,, ...I.]? =: 15.050 - 0.1535~ = - 0.300 + 0.1535~.5.93"'7 -589'2210.87[a]?= 15.784 - 0.1429~ = + 1.494 + 0 1 4 2 9 ~ .7 -38'8.9110 * 4511.98The second set of formula are obtained from the first bp takingp = 100 -q, where q = the percentage of water in the solution. Itshould be noticed, that whilst the variation for concentration, withinthe above limits, is constant.the increase of specific rotation for agiven pise of temperatare diminishes with increasing temperature.Taking this into account and using the above formulae, the authorhas calmlated the following more complete table :-8.03'9.5110.9912.47Spec& Rotation [a]= of Tartaric Acid.p . 1 t = 10".--I--t = 15".6-67'8.269 -8511 *44I-- -- t = 30". ---8 -64'10.0711-5012 -93[.IF= 14.615 - 0.158813 = - 1.265 + 0.1588q.These results lie between those obtained by Krecke (Arch. Ne'er-landaise, 7, 102) and those by Arndtsen (Ann. Chini. Phys. [ 3 ] ,54, 411).The author finds that a solution of tartaric acid (50 per cent.) maybe kept for months withont undergoing any optical change.Determinations of the rotary power of varying mixtures of tartaricand citric acids and water, tartaric and acetic acids and water, andtartaric and sulphuric acids and water were made.The resultsobtained lead to the conclusion that the two acids present appropriatewater in the proportion in which they aye present, or, in other words,that the solution consists of a mixture of solutions of the two acidsof equal strength. Thus, for instance, if 30 grams tartaric acid and20 grams citric acid are dissolved iii 50 grams water, the tartaricacid will appropriake 30 grams, the citric 20 grams of this water, andthe specific rotation of the tartaric acid will be that of a 50 per cent1 4 ABSTkACTS OF CHEMICAL PAPERS.solution. Tn the case of sulphuric acid and tartaric acid, the formerappears to be present in the shape of its hexahydrate, HsSO,.Theseresults seem to show that from such observations, it will be possibleto determine the state of hydration in which various substdances existin solution. L. T. T.Molecular Movements. By G. KRGSS (Ber., 18, 2586-2591).-Although the kinetic theory of gases gives some account of the trans-lation of molecules through space, yet no satisfactory hypothesis hasbeen brought forward to illustrate either the rotation of the moleculesabout their own axes, or the interatomic movements within the mole-cules. These two last the author classifies under the title of ‘‘ innermolecular movements.” Prom the undulatory theory of light, deduc-tions can be drawn regarding these molecular movements, inas-much as the vibration of the ether, which fills the intramoleculars p c e , is conditioned within that space by the velocity and amplitudeof the molecular vibrations.Thus if X be the wave-length of a rayemitted by a substance, v the velocity of light, the number of vibra-tions, n, which a molecule sends forth by rnovements of it as awhole and of its parts, can be determined by the equation n =: x’The phenomena of emission and of absorption spectra thus throws Somelight on the least and most extensive form of this inner molecularmovement. I n this paper, this latter point is discussed, together withits relation to the interatomic attraction, which is conditioned by thechemical constitution of the molecule ; inasmuch as vibrations of theparticles of a body are capable of being excited only by vibrationsof a like period in the external ether, so from the wave-lengths ofthose rays of light, which are absorbed to the greatest degree by thesolution of any substance, the numher of the vibrations of the mole-cules within the liquid can be calculated from the equation above.These positions of greatest absorption for derivatives of indigo andfluoresce’in have previously been determined by the author (Abstr., 1883,1042), and from the observations, resiilts are obtained for the maximumnumber of vibrations for billionths of a second. In a table are given theresults for indigo, its paraffino’id-, bromo-, nitro-, and amido-derivatives,for rosolic acid and its tetrabromo-derivative? and for fluorescein andits potassiom, bromo-, nitro-, and paraffino’id-derivatives.From the numbers given, it follows that the molecule of a com-pound emits fewer vibrations per second, the greater the number ofhydrogen-atoms, or! in the case of analogous replacements of thehydrogen-atoms, the zncrease or dewease of molecular vibrations i s pro-portiond to the number of hydrogen-atoms thus replaced. The resultsare in accordance with those deduced by Kellstab from experiments v. H. v. on the transpirability of homologous compounds.Simple Burner for Monochromatic Light. By NOACK (Chem.Centr., 1885, 497-498) .-Consists of a hydrogen evolving apparatus,jnto the cork of which is inserted the stem of a Bunsen burner madeof glass, and a wire for lowering or raising a block of metallic zinc.The salt for producing the required light is dissolved in the acid.J. K. CINORGAVLC CHEJIISTRY, 15An Aspirator. By A. GAwAr,ovsKI (Chern. Centr., 1885, 465).-A description of an aspirator, consisting of two vessels, revolving onan axis, and so constructed that it can be used as an aspirator orrespirator. P. P. B.New Apparatus for Chemical Laboratories. By A. KALEC-SINSZEY (Chem. Centr., 1885, 545--546).-To expel sulphuric acid inthe course of analysis, the author employs a wide glass tube sealed atthe lower and upper extremities, the upper end being driven inwardsto receive a platinum crucible fitted in with asbestos, and having asmdl open tube inserted laterally. Through this tube sulphiaric acidis passed into the apparatus ; the tube is connected with ,z suitablecondenser, heat applied, and the liquid contents of the platinumcrucible speedily evaporate. The author also describes a simple appa-ratus for obtaining an air blast by means of air and water droppinginto a large flask. J. K. C.By C. M.STUART (Chew. News, 5 2, 208) .--9 modification of the glass hooddescribed by Hempel (Ber., 18, 143i), so arranged as t o be placed onevery working bench.A Gas Regulator constructed without Metal. By H. SCRIFF(Rer., 18, 2833-2841).-The arrangement cannot well be describedwithout a figure.Improved Method of Ventilating Laboratories