20960" glass prism . . . . . .Rutlierford grating.. . 60 quartz prism.. . . . .General and Physical Chemistry.C. n ! ? ! E. 6 . F.2 .--------- ----+ 7-50 + 7.67 + 9 *83 + 7 -50 + 9.33+ 8-28 + 9.06 + 9.53 + 9.06 + 13.75- - 4'10 - 2-27 - 6.36 - 4.32Coloration of the Hydrogen Flame. By S. SANTINE (Gazzettn,14, 142--146).--Tt is generally stated that hydrogen burns with acolourless flame ; but it is here shown that under certain conditions theflame is coloured, and that this effect does not result from impuritiesin the materials used for generating the gas. The phenomenon is themore marked if a tube is placed over the flame, as in the chemicalharmonicon, when the various colonrs of the spectrum can be observedby varying t,he conditions of the experiment.I n general the centreof the flame is green, while the external envelope is of a violet-bluecolour; by reducing the pressure of gas, the blue colour becomesgreen, and then successively yellow, orange, and red. Thus, bydecreasing the intensity of the combustion, whether by the less directcontact of the oxygen with the hydrogen in the centre of the flame,or by st diminution of the pressure, the refrangibility of the emittedlight decreases. The author considers that the variations of thesolar mectrum mav arise from differences in the densitv. and conse-quentli of the lukinosity of the hydrogen contained wi<hin the solarphotosphere. V. H. V.Influence of Temperature on Spectroscopic Observationsand Measurements. By G. K R ~ ~ S S (Bey., 17,2732 -2739) .--In theexperiments described in this paper, the room in which the obser-vations were made was heated to various temperatures, a t which itwas kept constant for some hours, the observations being taken whenit was ascertained that the temperature of the spectroscope was thesame as that of the surrounding air.Comparative experiments aredescribed with a 60" glass prism, a 60" quartz prism, and a Ruther-ford grating, and these show that very appreciable errors may beintroduced by a difference in temperature of 25" :-The figures represent the amount of deviation in units of the scaleseniployed, the sign + indicating that the deviation is towards theviolet, the sign - that it is in the opposite direction ; the mean errorof observation is about 0.31 unit, whilst the deviation for 1" is0.366 unit.The following table shows a comparison in wave-lengths,T being the scale-number :-!I VOL. XLTlII 210 ABSTRACTS OF CHEMICAL PAPERS.I l-T.1169 -41432 -91801 -51863 *121M -8656 -8589 -7527 -4517 -7486 -5658 *9592 *O529 .O519 -2488 ‘0A. K. M.Specific Refraction in Reference to the Double Bond. ByR. NAS~NL (Gaxzetta, 14, 150--156).-The author, in association withBernheimer, has shown, principally from experiments on the naph-thalene-derivatives and cinnamic acid, that Bru hl’s hypothesis thateach pair of carbon-atoms, combined together as in the olefines (theso-called double bond) increases the molecular refraction (Gazzetta,13, 137) is incorrect.Recent experiments by Kanonnikoff on thesame class of derivatives tend, however, to confirm this hypothesis.The cause of this discrepancy is examined in the present memoir.The difference in the results arises from the fact that Kanonnikoffused solutions of those substances, whereas Nasini’s and Bernheimer’sexperiments were conducted with the solids or liquids themselves, aprocess more likely to give trust worthy results.On a comparison of the results obtained with cinnamic acid, naph-thalene, bromonaphthalene, and a-naphthol, the difference of the valuefor A is in one case more than 2 units, or practically equal to the sup-posed difference produced for each pair of double-linked carbon-atoms.Kanonnikoff’s experiments, however, show that the difference of2 units is not constant, but in certain naphthalene-derivatives adifference of 3.6 units is noticed, a result which is explained away bythe great dispersive power of these substances (see Gladstone, Trans.,1884, 254-259).In the case of naphthalene tetrachloride, whosedispersive power is certainly riot greater than that of many benzene-derivatives, the increase of specific refraction A is 8.66 instead of6 units as required hy Briihl’s hypothesis. The only argument whichmigllt tend to explain these abnormal variations is the want of exact-ness in the constant A, but even this would militate against ratherthan support Kanonnikoff’s views; for the values f o r A and ofP k1 increase with the number of constants used for their calcu-tion, as for example:-dP A A (two P A-2 (three A (two con- A (three d d&ants>.constants). constants). constants).Dimethylnaphthalene 1.5637 1.57476 87.02 88.73Methyl-a-naphthol . . 1.5721 1.58953 82.44 84.29In conclusion, Kanonnikoff’s views regarding the const,itution offurfuraldehyde and pyromucic acid, based on the determinations oftheir molecular refraction, are criticised, for the formuh assigned tGENERAL AND PHYSICAL CHEMISTRY. 21 1ma.0AI 1 HC-CHHC=CHOH.C=C.COH] I , respectively point to a them, HC-C.COOH andwide difference of constitution, although, in its reactions, furfuraldehydecomports itself its the aldehyde corresponding with pyromucic acid.V. H. V.Refractive Power of the Hydrocarbon C,,H,,.By A. ALBITZKY(J. pr. C'hem. [Z], 30, 213--214).-This hydrocarbon was preparedfrom ally1 dimethyl carbinol by Nikolsky and Sayt'zeff's method(Abstr., 1879, 214). The sp. gr. and refractive indices were deter-mined with a portion boiling at 195-199'. The specific refract'ionshows that in this hydrocarbon three of the carbon atoms are unitedby double linkage.The following a1.e the results of the determinations :-Sp. gr. a t0" = 0 8512, a t 9.8" = 0.8449, at 21.4" = 0.8349, at 18.4" (calc.) =0.8381 (water a t 0" = 1).Refractive indices for hydrogen lines a, (3, y, and for sodium line Da t 18.4" are:-w. 9- A. B.____---,--- ---1 '48537 1 -49369 1 *45667 0 -69829~~~ ~ ~ ~~P. P. B.Dispersion of Sodium Chromate. By G. WYROUBOFF (Juhrb.f.Xin., 1885, 1, Ref., 25).-This salt, sodium chromate with 4H20,described by the author in 1880, is remarkable for its strongly inclineddispersion of the bisectrices and strong dispersion of the axes. Theacute positive bisectrix forms with &, in the obtuse angle p, an angle of10" 21' for red light, and 7" 49' for green light. The angle of theaxes is 16" 10' for red, and 32" 22' for green (in air). Well preparedspecimens in Canada balsam last for a considerable time.B. H. B.Electric Conductivity of Amalgams. By C. L. WEGER (Ann.Phys. Chern. [2], 23, 447-476). -The experiments of Matthiessenand Vogt on the influence of a foreign metal on the conductivity ofmercury, led to no satisfactory results, owing to the difficulty ex-perienced in the production of a homogeneous material.The experi-ment herein detailed, shows that the conductivity of amalgams of tinand mercury increases with increase of temperature, and vice verm ;212 ABSTRACTS OF CHEMICAL PAPERS.but that these changes are regular when a small percentage of tin onlyis added.The thermoelectric positions of various amalgams of copper arealso compared with t h a t of pure mercury: the presence of the foreignmetal in all cases diminishes the difference of potential. Thoseexamined may be arranged in the following series (if 0.5 gram of themetal be added to 100 grams of mercury) : tin, silver, lead, zinc,cadmium, and bismuth. The specific resistance of the combinationdecreases with increase in the amount of metal added.A comparisonof the galvanic resistance and thermoelectric difference of potentialshows that in all cases, with the exception of cadmium, increase ofthe former is correlated with increase of the latter.In conclusion, the author remarks on the advantage of mercuryas the metal for comparison in thermoelectric series, as reproduciblein a homogeneous state, and as the only metal which shows no differ-ence of potential when one portion is warmed and the other cooled. v. 11. v.Electric Conductivity of Solution of Carbonic Anhydride.By E. PFEIFFER (AWL Phys. Chem. [2], 23, 625-650).-The ex-periment.s of Hittorf on .the migration of the ions during electrolysispoint to the importance of electric functions in deciding the chemicalconstitution of solutions of gases i n water.Kohlrausch has alsoproved by experiments on the electric conductivity of solutions ofammonia, that these do not contain the hypothetical combination-ammonium hydrate. I n t h i s paper, an account is given of experi-ments on solutions of carbonic anhydride under increased pressuresyarying from 1 to 25 atmospheres. The following are the principalresults :-(i.) A 601UtiOn of carbonic anhydride in water forms one of theworst conductom known .: the aonductivity under normal conditionsbeing about one-twentieth of that of spring-water.(ii.) Although it is commonly assumed that a solution of carbonicanhydride in water contains the hypothetical carbonic acid, H&O, inthat it possesses an acid reaction, yet according to Kohlrausch’s ex-periments the conductivity of such a combination should be equal to202,000 = C.G.S.units, or more than a thousand times greaterthan the highest value fmnd.(iii.) Change of pressure produces no alteration in the conductivity,which would appear to show that the carbonic auhydride is liquefiedin the process of solution.(iv.) Carbonic anhydride is soluble in water a t temperatures aboveits critical point; if then the solution were a mixture of water andliquid carbonic anhydride, it is probable that irregularities in its con-dactivity would be observed at the critical point, but this is not thecase.(v.) The curve of the conductirity as a function of the femperd-ture is analogous to the curves dacribed by Kohlrausch for oxalic,tartaric, and acetic acids, in that it ascends rapidly for increase ofdilution. This would seem to point to an analogy of constitution ofu solution of carbonic anhydride in water with these acids.V.H. VGENERAL AND PHYSICAL CHEMISTRY. 213Influence of Magnetisation on the Resistance of MagneticLiquids. By F. NEESEN (Ann. Phys. Chem. [a], 23, 482-493).-Former experiments on the influence of magnetisation on the conduc-tivity of magnetic liquids have led to negative results. I n this paper,an account is given of an investigation on the effect produced by thernagnet'isation of ferrous sulphate as regards its electric conductivity.It would appear, so far as the experiments would permit of a conclu-sion, that if the lines of the magnetic field are normal to the direc-tion of the electric current, no effect is produced, but if the two areparallel to one another, the electric conductivity is increased andeventually the electromotive force of the polarisation of the liquidappears to be diminished.V. H. V.Diathermancy of Esculin. By K, WESEENDONCK (Ann. Phys. Chem.[2], 23, 548--553).-Lommel has concluded from his researches thatfluorescent substances are divisible into two classes ; the members ofthe one display marked absorption-bands in the visible part of theBpectrum, but do not follow Stokes' law, while those of the other,although in accordance with that law, do not shorn these absorptionphenomena in such a marked degree. The author has examinedwhether in substances of the second class, of which aesculin wasselected, absorption-bands cannot be detected in the ultra-red portionof the spectrum, but the results obtained were negative.V. H.V.Tension of Aqueous Vapour of Hydrated Salts. By W.SIISLLER-ERZBACH (Ann. Phys. Chem. [el, 23,607--625).-The experi-ments of Naumann and Kraus on the tension of water-vapour evolvedin a Torricellian vacuum from hydrated salts, led to unsatisfactoryresults, owing to the reabsorption of the emitted water by the par-tially dehydrated salt, when the tension of the former had reached acertain point. The observations are also complicated by the con-comitant alterations of the tension of the vapour of mercury. Thomethod described in this paper is based on a comparison of the lossexperienced, by two suitably constructed tubes of the same dimen-sions, the one containing the salt to be examined, the other distilledwater, both enclosed over sulphuric acid.I n the experiments hereindescribed it is shown that there is practically a constant ratio betweenthe diminutions in weight experienced by the tube for each definitecombination of the salts with their water of crystallisation. Thus a,convenient method is presented for determining the nature and degreeof combination of the molecules of water with the molecules of salt.The following results were obtained :-There are three definite com-pounds of disodinm hydrogen phosphate, with 2, 7, and 12 rnols. H,Orespectively ; two compounds of' sodium carbonate with 1 and 10 mols.H20 ; two compounds of sodium borate with 5 and 10 mols.H,O. The10 mols. H20 of crystalline sodium sulphate seem to be combinedin an equal degree. The last molecules of water of crystallisation ofsodium phosphate and carbonate are removed by a saficiently longexposure over sulphuric acid (comp. Abstr., 1884, 952). V. H. V214 AESTRAOTS OF CHEMICAL PAPERS.Condensation of Carbonic Anhydride on Glass. By H.KAYSER (Ann. Phys. Chem. [ S ] , 23, 416--426).--Runsen’s researcheson the condensation of carbonic anhydride on glass are in directopposition t o former observations (comp. Abstr., 1884, 146), in thathe found that the phenomenon was incomplete after three years, thatalteration of pressure was without effect, and that the condensationincreased with rise of temperature.The author has repeated theseexperiments with the following results :-(i.) The condensation iscompleted a short time after the introduction of the gas, provided thatthe glass surface is perfectly free from other gases; other less con-densible gases are ousted by the carbonic anhydride. (ii.) The qnan-tity of gas condensed increases with rise of pressure and decreaseswith diminution of pressure; it increases with diminution of, butdecreases with rise of temperature. These results are i n accordancewith former observations with other gases. The author remarks onthe inadvisability of applying the name “ diffusion ” to this phenome-non of the condensation, or “ absorption ” of gas on glass : for theformer term is applied to the most various phenomena.The name“ penetration ” is proposed as more applicable and suggestive.V. H. V.Combustion of Hydrocarbons and their Oxides and Chlo-rides with Mixtures of Chlorine and Oxygen. By G. ScHLEGEr,(Annalen, 226, 133--174).-1t has been shown by Botsch (Abstr.,1882, 456), that in the explosion of a mixture of hydrogen, oxygen,and chlorine, water is formed only when the chlorine is present inamount insufficient to unite with the whole of the hydrogen; thisresult is important, inasmuch as it does not agree with the generallyaccepted rule that when several substances react simultaneously onone another those reactions always occur in which t’he greatest amountof heat is developed. The author has extended these researches to theproducts of the explosion of mixtures of chlorine and oxygen withgaseoub organic compounds.Experiments were made with excessboth of chlorine and oxygen, with an excess of oxygen and an amountof chlorine insufficient to unite with all the hydrogen present, andfinally with an excess of chlorine, but with an amount of oxygeninsufficient to convert the whole of the carbon into carbonic: anhy-dride. The organic substances employed were methane, ethane, pro-pane, butane, methyl ether, methyl chloride, ethyl chloride, acetylene,and carbonic oxide. NG results could be obtained with ethylene,as it unites with chlorine in the dark, and so prevents the formationof an uniform mixture for expIouion. The following are the conclu-sions drawn from these experiments:-(1.) If it hydrocarbon bemixed with excess of chlorine and excess of oxygen and the mixtureexploded by the spark, the whole of the carbon is converted intocarbonic anhydride and all the hydrogen into hydrochloric acid.Hydrogen does not unite with oxygen nor carbon with chlorine.(2.) If excess of oxygen be employed together with Sn amount ofchlorine insufficient to combine with all the hydrogen present, thenthe remainder of the hydrogen unites with oxygen.(3.) If withexoess of chloriue the amount of axygen is insufficient to convert allt,he carbon into carbonic anhydride, there is then also formed carboniINOROANIC CBE MISTRY. 215oxide, the proportion of this latter increasing with the deficiencyof oxygen. (4.) If neither chlorine nor oxygen is present in siiffi-cient quantity for complete combustion, carbon is separated.(5.) Theorganic chlorides and oxides experimented with behaved in likemanner to the hydrocarbons.Determination of Specific Gravity of Carbonic Acid Solu-tion. By A. BLUMCKE (Am. Phys. Chem. [ a ] , 23, 404-415).--Observations on the change of volume in a liquid produced by theabsorption of gases have for the most part been made under normalnOmospheric conditions. In this paper a method is described, on thehydrostatic principle, by means of which the sp. gr. of solutionsof carbonic acid under increased pressure can be determined. Aseries of these determinations are given, made under pressuresvarying from 2 to 37 atmospheres ; in all cases i t appeared that theabsorption of the gas was the more marked the greater the initialpressure.The results point to the following empirical formula forthe sp. gr. of solutions of carbonic acid: S = ____0.001965 is the weight in granis of 1 C.C. of carbonic anhydride,and 0.001568 is the constant deduced from the experiments. Hencethe addition in volume by the absorption of carbonic anhydride isdirectly proportional to the gas absorbed, if the compressibility of theliquid by increase of pressure is neglected. Although the results showR remarkable diminution in volume experienced by the carbonicanhydride in its absorption by water, yet no conclusive proof isoffered of the liquefaction of the gas in the course of solution,especially as Andrews’ experiments show that the critical point O E agas is lowered by its admixture with another gas or vapour of avolatile liquid. V. H. V.A. J. G.1 + n.001965, in which1 + n.001568Crystallisation. By C. MARIGNAC (Bey., 17, 2831-2832), and by0. LEHMANN (Bey., 17, 2885-2886) .-Replies to Briigelmann (thisvol., p. 114).Lecture Experiments. By A. VALENTINI (Gazzefta, 14, 214-218).-In this paper various forms of apparatus are described for thecombustion of substances in oxygen, and chlorine ; the preparation ofozone by Schonbein’s method ; the preparation of chlorine ; the com-bustion of ammonia in oxygen, a,nd chlorine; and the oxidation ofammonia. Drawings of thk-various pieces of apparatus are given.V. H. V