93 General and Physical Chemistry. Chemical Changes produced by Sunlight. By E. DUCLAUX (Compt. rend., 103, 881-882).-Many organic compounds are affected hy solar radiation in the same way as by microbes, the products of the change being water and carbonic anhydride, with other substances which are relatively stable in the conditions under which tEey are produced, and are identical with the products of the action of microbes. Cane-sugar in neutral or alkaline solution is not affected by pro- longed exposure to sunlight, but if slightly acidified even with an organic acid it is readily inverted by solar radiation. The solution of invert sugar undergoes no further change so long as it remains acid, but if made alkaline the glucose is rapidly decomposed with formation of water, carbonic anhydride, oxalic, formic, and acetic acids, and about 3 per cent. of alcohol.A similar change takes place, although less rapidly, out of contact with the air, and hence it is evident that the decomposition is due to internal combustion. Lactose and lactates also yield alcohol under similar conditions. The exact nature of the change in any case is modified by the nature’ of the source from which oxygen is absorbed (air, salts of platinum, gold, mercury) ; but the chief products are practically the same from all substances. These products are alcohol, oxalic acid, acids of the acetic series, leucine, carbamide, carbonic anhydride, water, &c. Certain differences are, however, observed. Tartaric acid gives aldehyde in place of alcohol, and the alcohols, if oxidation is regular, tend to produce the corresponding acid of the acetic series.Practical Methods of Photographing the Spectrum. By J. M. EDER (Monatsh. Chem., 7 , 429-454) .-This paper .contains a description of some practical methods of photographing the various parts of the spectrum by silver bromide gelatin plates sensitised by different dyes. The preparation of the plates and the processes used for the development are described in full, and accompanied by copies of photographs taken. For spectra from the ultra-violet to the yellow, about D, the best dyes are erythrosin, henzopurpurin 4B, and yuinoline-red ; from the ultra-violet to the red cyanin, is the best ; from the orange to the red, ccerulein with red glass, and “sensitive green,” R dye from para- hydroxybenzaldehyde and dimethylaniline, are recommended.These plates, sensitive to the green, yellow, or red part of the spectrum, are suitable for photography by petroleum and gas light, and for taking photographs of gilded documents and papyri, of microscopic prepam- tions. and of clouds on a blue sky, interposing yellow glass to subdue the blue. Excellent photographs of stars have been taken with tha C. H. B. aid of these plates. v. H. v. VOL. LII. h94 ABSTRACTS OF CHEMICAL PAPERS. Electrolysis Of Carbon Compounds. By .T. HABERhIANN (Monntslz. Chem., 7, 529-551).-1n continuation of former experi- ments on the electrolysis of carbon compounds (Abstr., 1881,215), the author describes the resalts which are obtained under various con- ditions with alcohol acidified with sulphnric acid, or rendered alkaline by soda, and with potassium acetate dissolved in methyl alcohol or its homologues.The sources of electrical energy used were a thermo- battery of 120 elements, a Smee’s battery of 16 elements, and a dynamo- machine of one horse-power. On electrolysis, alcohol acidified with sulphnric acid yields hydrogen evolved as gas at the negative pole, aldehyde, and after prolonged action aldehyde-resin together with ethyl hydrogen sulphate. The main reaction is therefore C2H,0 = C2H40 + H,. If the alcohol is rendered alkaline, or is in the form of sodium ethoxide, the products of decom- position are hydrogen, carbonic anhydride as sodium carbonate, an aldehyde-resin insoluble in ether and alcohol, together with a soluble modification, and a subshance allied to cinnamaldehyde.A concentrated solution of potassium acetate in ethyl alcohol yields a mixture of hydrogen and ethane together with potassium ethyl carbonate, by the mutual decomposition of the salt and acid. In fact, the process serves as a convenient method for the preparation of potassium ethyl carbonate in large quantities, as the salt separates in fine crystalline aggregates. It is quickly decomposed by water, but dissolves in absolute alcohol without change. The results obtained with solutions of potassium acetate in methyl and butyl alcohols were unsatisfactory. V. H. V. Phosphates. By BERTHELOT (Compt. rend,, 103, 911-917).- When ammonium chloride is added to a solution of trisodinm phos- phate there is an absorption of heat which varies with the proportion of ammonium chloride, being 5.96, 5.63, 4.84, and 2.62 cal. for 3, 2, 1 and 4 mols.of ammonium chloride respectively. Complete decom- pwition of the sodium phosphate would correspond with an absorption.of heat equal to -6.4 cal., and hence it is evident that t,he action of the ammonium chloride is almost complete, although the water exerts a greater dissociating effect on the ammonium pbosphate than on the sodium salt. I f trisodium phosphate is added to a solution of a magnesium, barium, strontium, calcium, or manganese salt,, a colloidal precipitate of the insoluble phosphate is at first formed, and there is considerable absorption of heat, but after some minutes the precipitate becomes crystalline and a large quantity of heat is developed.The heslts of formation of the colloidal and crystallised phosphates are given in the following table :- Colloidal. Crystallised. Magnesiuni hydrogen phosphate., 50.6 ,, 54.2 ,, Magnesium phosphate .......... 57.8 cal. 83.0 cal. Barium phosphate ............. 68.4 ,, 1008 ,, Strontium phosphate .......... 65.4 ,, 97.4 ,, Calcium phosphate 64.0 ,, - Manganw? phosphate .......... 45.8 ,, 53.5 ,, ............ 9 ,GENERAL AND PHYSICAL CHEMISTRY. 95 In the case of barium phosphate, the sodium phosphate must be added to the barium chloride, and not vice uers$, otherwise the change to the crystalline state is Loo rapid. The phenomena now described explain the discordant results obtained by Louguinine and the author for the heat of neutralisation of phosphoric acid by baryh, and also the differences observed by Blarez (this vol., p.7) between the heats of formation of barium phosphale and barium arsenate. In the case of strontium also, the change to the crystalline condition is extremely rapid, if the strontium solution is poured into that of the trisodium phosphate. Calcium phosphate was obtained only in the colloidal form. The heats of formation of the collo'idal insoluble phosphates do not differ to any great extent from the heat of formation of an equivalent quantity of trisodium phosphate, 33.6 x 2 cak. In other words, the precipitate in its initial condition corresponds clsseIy with the soluble salt from which it has been derived, a further example of the tendency of systems which are undergoing transformation to preserve their molecular type.On the other hand, the new phosphates may be dissociated by water to a greater extent than the sorubre phosphate from which they have been formed; and this dissociation ail1 be accompanied by an absorption of b a t , This absorption is practically wil with barium phosphate, which appmximates closely to the alkaline phosphates, but ib is very cfistinct wihh magnesium phosphate, which is more readily dissociated. In dissolved trisodium phosphate, the third and even the second equivalents of the base are less intimately combined with the acid than the first atom, and are partially separated from it by the dissociating action of the solvent. There can be little doubt that this imperfect state of combination also exists in- the colloidal insoluble phosphates, tlie formation of which is due b a polyalcoholic rather than an acid function of the phosphoric acid.The combination, however, soon becomes more intimate, and the alcoholic function changes to an acidic function comparable with that 04' ordinary tribasic acids, the change being accompanied by development of heat, and crystallisation of the phosphates. The actual development of heat is mnch greater than can be supposed to be due to the mere physical change from the colldidal to the crystalline condition, even if the change were accompanied by eombination with water. As a matter of fact, the erystallised phosphate contains less water than the colloidal phosphate. In their new condition, the heats of formation of the insoluble phos- phabes become practically treble that of the ordinary monophosphates, or in other words, the three acid functions become equivalent to one another, and to this change is due the greater proportion of the heat developed in the passage from ihe colloidal to the crystalline form.Heats of Neutralisation of Homologous and Isomeric Acids. By H. GAL and E. WERNER (Comyt. rend., 103, 806--809).-The author has determined the heats of neutralisation of isobutyric, isopropy la ce tic, t rime thy lace tic (pivalic) , caproic, isobu tylace tic. and sorbic acids, and his results, together with the heats of neutralisation of the lower acid8 of the acetic series, as determined by Berthelot, C. H. B. h 296 ABSTRACTS OF CHEMICAL PAPERS. Lougninine, and others, are given in the following table.Heat of solution of isobutyric acid, directly + 0973 cal., indirectly + 1.012 cal. ; isopropylacetic acid, directly + 1.167, indirectly + 1.030. Heat of Acid. neutralisation. Formic acid, H-COOH ........................ 13.3 Acetic acid, MeGOOH ........................ 13.4 Propionic acid, CH,Me*COOH .................. 14.3 Normal butyric acid, CHF,Me*CH2*COOH ........ 14.4 Isobutyric acid, CHMe,*COOH. ................. 13.9 Normal valeric acid, CH2Me*CR2*CH,*COOH.. .... 14.4 Tsopropylacetic acid, C HMe2*C H2* C 0 OH ......... 14.4 T rime thylace tic acid, CMe3*COOH .............. 13.6 74 Normal caproic acid, CH,Me*CH,*CH,*UH,*COOH . 14.689 Isobu tylilcetic acid, CHMe,*CH,*C 0 OH 14-5 i .......... { Omitting formic and acetic acids, the heat of neutralisation of the other acids, with the exception,of isobutyric and trimethylacetic acids, is practically constant, and varies between 14.3 and 14.6.Isobutyric acid is a secondary acid, and trimethylacetic acid is ft tertia1.y acid, and it would seem therefore that the heat of neutralisation of primary acids is greater than that of secondary acids, whilst that of tertiary acids is somewhat smaller atill. The heat of neutralisation of sorbic acid, which is regarded by Menschutkin as a tertiary acid, is 12.945. C. H. B. Heats of Neutralisation of Malonic, Tartronic, and Malic Acids. By H. GAL and E. WERNER (Compt. rend., 103, 871-873) .- MaZonic Acid.-Heat of solution at 10° = -4.573 cal. Heat of neutralisation by soda : 1st equivalent, 13.342 cal, ; 2nd equivalent, 13.778 cal.; total, 27.120 cal. Heat of neutralisation by soda : l e t equivalent, 13.71 1 cal. ; 2nd equivalent, 11.856 cal. ; 3rd equivalent, 0 0 cal. ; total, 25.567. Mulic Acid.-Heat of solution at 20" = -3,148 cal. Heat o€ neutralisation by soda : 1st equivalent, 12.730 cal. ; 2nd equivalent,, 12.189 cal. ; 3rd equivalent, 0.0 cal. ; total, 24.919. The heat of neutralisation of oxalic acid is 28.1 cal. (Berthelot and Thomsen) ; of succinic acid, 26.4 csl. (Chroutschoff) ; and tartaric acid, 25.3 cal. (Berthelot). I t is evident from these values that the heat of neiitralisation diminishes as the molecular weight increases. The intzodnction of the OH group into oxalic, malonic, and succinic acids lowers the heat of neutrdisation by about 2 cal. A similar difference has previouely been observed between propionic and lactic acids, and between benzoic and the hydroxybenzoic acids.Themnochemistry of Reactions between Magnesium Salts and Ammonia. By BERCHELOT (Compt. rend., 103, 844-848) .- When magnesium sulphate solution is mixed with an equivalent quantity of sodium hydroxide solution, there is an immediate develop-, Tartronic Acid.-Heat of solution at 12" = -4.331 cal. C. H. B.GENERAL Ah'l) PHYSICAL CWMBTRY. 97 ment of +0*18 cal., but the development of heat gradually slackma, and at the end of 10 minutes is + 1-14 cal. ThB successive develop- ments of heat are due to the fact that a basic srtlt is first formed, which is afterwards decomposed by the soda, and also to the hydra- tion, contraction, $c., of .the precipitate.Magnesium chloride m d sodium hydroxide behave in like manner. At first there is an absorp- +ion of -0.32 cal., and afterwards a development of 44-32 cal., the final result being nil. It is evident, &s the reseamhes of Thomsen, Favre and Silbermann, Ditjte, and othere have already indicated, that the heat developed by the action of acids on magnesium hydroxide approximates closely to thttt developed by their action on potash and soda. The action of ammonia on magnesium sulphate is accompanied by an absorption of -0.24 cal., whereas if the magnesium were com- pletely displaced, 3.0 cal. should be absorbed. The difference is due to the formation of double salts or oxides, the production of which is accompanied by a development of + 2.8, cal.With magnesium chlo- ride, the difference between the calculated and observed values is +2.2 cal. If magnesium sulphate is mixed with 2 mols. of ammonium chloride, +0.32 cal. is developed, and if an equivalent quantity of ammonia i q now added, there is a further development of +0.26 cal., the total de- velopment of +0*58 cal. being due to the formation of a complex oxide, the heat of neutralisation of which is 0.33 cal. higher than the sum of the heats of neutralisation of magnesium oxide and ammonia separate1.v. When magnesium chloride is mixed with ammonia, there is an absorption of -0.48 cal., and if ammonium chloride is then added there is a, development of +0*56 cal., the sum being 0.08 cd., from which it followa that the heat of neutralisation of the complex oxide by hydrochloric acid is practically identical with that of magne- aium oxide, If magnesium sulphabe OF chloride solution is mixed with sodinin hydroxide, and ammonk then added, the greater part of the precipi- tate redissolves, but there k no sensible $herma1 disturbance, a result which indicates that the heat of solution of the precipitate is idenfical with its heat of combination with the solvent. If, oa the other hand, magnesium sulphafe i s first mixed with ammonia, md the sodium hydroxide added afterwards, there is a development, a€ +Is90 cal., probably due to the facf that, the order *of admixture being reversed, the liquid requires a much longer time to attain the same condition.The differenee betweert the observed thermal d i s t n r b c e and the de- mb ment of heat resulting fmni the action of soda or magnesium mlp!ka alone ia a, fnrther proof of the formation of complex corn- peunds.I f magnesium snlphate is mixed with 2 mals. of ammonium chlo- ride and sodium hydroxide then added, +3.64 cal. are developed, and some permanent precipitate is formed. The thermal disturbance is greater than that which would colrwpond with the displacement of ammonium by sodium, rtnd the difference indicah the cornbination of magnesia and a;mmonia with formation of ammonio-magnesium sul- phate. If 4 mols. of ammonium chloride fire added at the begia-9s ABSTRACTS OF CHEMICAL PAPERS, ning, no precipitate is formed, and the heat developed is +3.90 cal. JVith magnesium sulphate, the excess of heat developed above that corresponding with the decomposition of the ammonium salt is + 1.2 cal., with the chloride it is +1*0 cal. From these results it follows that the complex ammonio-magnesium bases in uniting with sulphuric or hydrochloric acid, develop about + 1.8 cal.more than pure ammonia, and + 0.3 cal. mow. than magne- sium oxide. The association of ammonia with a metallic oxide such as magnesia would seem to result in the production of a complex alkali analogous to tetramethylammonium oxide, with an energy greater than that of metallic oxides, and approaching +ha& of the strongest alkalis. C. H. B. Heats of Combustion and Formatiun mf Homologous Phe- nols. By 3’. STOHMAKN, P. RODATZ, and H. HERZBERU (J. pr. Chem. [2], 34, 311-327).-1n this paper a series of determinations of the heats of combustion and formation of the homologous series of phenols are given in detail, as also their heats of liquefaction.The principal values obtained m e given in the following table :- Heat of combustion per gram-molecule. Phend (did), C,H,-OH. ..... .- .. 723659 Orhhocresol (liquid), CsH4Me-OH. .. 883008 Mehcresol (liquid) .............. 880956 Paracresol ................ 882900 Orcinol, C6H,Me(OH), (solid). ..... 824724 Orthoxylenol, C6H3.%fe2*OH (solid). . 1035434 Mehxylenol (liquid). ............. 1037499 9 araxylenol (solid) ........ -. ..... 1035638 Fseudocumenol, CBH,Me,-OH (solid) 119145 1 Carvacrol, CGH3MePr*OH (liquid). . 1354819 Thymol (liquid). ................. 1353750 .. (liquid) ................. 726002 ..(solid). ............. 879788 .. (solid) .............. 880441 .. (solid) .................. 1348982 Heat of formation. - 50992 53044 51100 109276 61566 5950 1 61362 68549 68181 69250 - - On a comparison of these numbers, it will be seen that every dis- g!acement of hydrogen bp a methyl-group corresponds with an incre- inent of 155356 cal. in the heat of combustion, a value praotically equal ta that obtained for the homologues oE methyl alcohol. Thus it follows that the displacement of‘ hydrogen by methyl, either in the so-called side-chain or i n the nucleus, corresponds with the same value for the heat-increment. Thus the value for ethylphenol will be equal t o that of xylenol. Similarly also, as the d u e s for carvacrol and thymol are approximately equal to that of pseudocumenol, namely, the introduction of the isopropyl-group produces the same effect as that of three single methyJ groups, then the heat values of the iso- are equal to those of normal-compounds.V. H. V.GENERAL AND PHYSICAL CHEIIISTKT. 99 Some Laws of Chemical Combination. By DE LANDERO and R. P R r E n , (Conzpt. rend., 103,934-935).-1f chemical combination is taken as the clashing together of the particles of the elements, and if each particle is regarded as possessing a constant velocity which is characteristic of the pctrticular element, the loss of energy resulting from the union of the non-elastic particles may be regarded as the equivalent of the quantity of heat developed by the combination. These considerations lead to the formula- (V + T q 2 , ee' = 2(a + e') in whichf = the heat of Combination expressed in calories, e, e' = the weights of the combining elements epuivaient to 1 gram of hydrogen, whilst V and V' are quantities which a m constant for each element and are proportional to the velocities of their particles.These quan- tities may be termed thermodynamic constants, or thermodynamic cquivdeuts, and their value is obtained by the €ormula- 9 * v'=y/2f--,,. e + e' Take the ease of the two copper bromida- Cuprous bromide: e + e' = 143.4; f = 25900 Cupric bromide: e + e' = 111.7; f = 17300 - + 38.269 cal.; V + V' = cal; v * V' = - + 39'039. Calculations with t i n bromides, mercury bromides, mercury iodides, &c., lead to similar results. Since V Ifi V' is the sum or difference of the thermodynamical equivalents of the two elements in each system ; i t is necessary to obtain the consfants of some of the elements from different sets of compounds, care being taken to use only thermo- chemical data referred to the solid state. The following table gives the thermodynamical equivalents of several elements, these values re- ferring in each case to that quantity of the element which is equivalent to 1 gram of hydrogen:- K ......45221 S ...... 47.874 A1 ...... 48.218 Nu.. .... 49.768 T1 ...... 5.223 Zn.. .... 13.073 Hg.. .... 9.079 Ag .... 12.i86 Bb ...... 5.155 B r . . .... 44.171 Cu .... 4.999 Si ...... 37.519 I ....... 32.416 Ca, ..... 50.309 C. H. B. The Law of Volumes in Chemistry. By T, S. HUNT (Chem. News, 54,206-207) .-The author advocates the universal application of the law of volumes to solids, liquids, and gases, which would render the application of the atomic hypothesis to explain the law of definite proportions wholly unnecessary.From this standpoint, the union of many volumes of vapour or gas to form a single volume of vapour or solid would be regarded as chemical combination; the reverse, namely raporisation, would be chemical decomposition, which wonld be without specific difference in the case of integral volatilisation, or100 ABSTRACTS OF CHEMICAL PAPERS. with definite changes, as in cases now regarded as dissociation. The difference between chemical and physical molecules would hence be quite evident. D. A. L. Velocity of Dissociation. By H. LESCCEUR (Compt. rend., 103, 931-933) .-The velocity of dissociation of acid sodium acetate, CzH,0zNa,2CzH40,, was determined by placing the compound in a small bell-jar which also contained soda-lime ; the temperature of the whole being kept a t 100".The mean velocity of dissociation during k i given interval is determined by dividing the time into the loss of weight of the compound. The results indicate the existence of a biacetate, CZH,O2Na,C2H1O2, and a sesquiacetate, 2C2H,02Na + Velocity of dissociation does not depend on the temperature alone, as Miiller-Erzbach siipposes, but also on the physical condition of the substance which is undergoing dissociation. In this particular case, the rate of dissociation increased fourfold when the acetate becttme solid, although the tension of dissociation did not change, and similar phenomena are observed with copper sulphate crystals, &c.CzHaOz. C. H. B. Nature of Liquids. By W. RAMSAY and S. YOUNG (Ohm. News, 54, 203-205).-1t is proved by various investigations that, above a eertain pressure and temperature, all liquids show an increase in the density of their saturated vapours beyond that deducible from the molecular formula, varying of course with the liquid. Some liquids, however, known to be dissociable, in addition show an increase also on fall of temperature and pressure below a certain tem- perature and pressure characteristic of the liquid. Reasoning from these facts, the following difference is suggested between stable and dissociable liquids :-In the former, the molecules exhibit physical but not chemical attraction ; in the latter both pliysical and chernical attraction are evident, inasmuch as, besides cohesion and surface ten- sion, there is evidence of molecular combination.The behaviour of .vapours at the moment the liquid is visible support this theory, for whereas vapours from dissociable liquids continue to rise in pressure i n spite of the decrease in volume and condensation of liquid (evidence of non-homogeneity of the vapour, owing in these instances to forma- tion of molecules of higher molecular weight), vapours from stable liquids do not behave in this manner, but the pressure in such case is the vapour-pressure corresponding with the temperature ; hence it may be concluded that the latter show no tendency to form complex molecular groups. With regard to the solvent action of a fluid above its critical point, the authors have worked with a solution of eosin in alcohol, taking the fluorescence as indicating solution.They find that solution existed at least for a short time at temperatures a little above the critical point, and at volumes smaller than the critical volume ; apparently, however, after some time the solid is wholly deposited as such on the walls of the tube. This is not conclusive, as the translucent red sub- starice deposited on the glass interfered with the detection of the fluorescence. According to the authors' view of the nature of liquids,GENERAL AND PH Y STCAL CHEMISTRY. 101 solution should be possible above the critical point provided the volume is sufficiently small. D. A.L. Capillary Constants and Meniscus Angle. By J. TKAUBE (J. pr. C'he?n. [2], 34, 292--31l).--l)eterminations are given for the value of the function a' cos 8 according to the formula rh = a2 cos 0, for aqueous solutions of. the alcohols of the paraffinoid series and acids of the acetic series at various degrees of concentration (comp. Abstr., 1885, 1033). The principal points to be noticed are that both propyl and isopropyl alcohols show a minimum value for tho function with mixtures of equal weights of the alcohol with water, and that the eurve for butyric acid at first decreases with increase of concentration up to 30 per cent., thence increases up to 50 per cent., and sub- sequently decreases. After a historical review of the literature on the magnitude of drops, an account is given of experiments, made with an apparatus previously described, permitting of the formation of drops from a capillary tube under constant or variable conditions of temperature and pressure.The weight of the drops was ascertained by deter- minations of the specific gravity and the number of drops in a constant volume. The results obtained with the above-mentioned alcohols and acids show that the volume of the drops is proportioual to the rise in height in the ca~illary tube, or their weight is proportiwrd to the product oj' the height and the specijiic gravzty. If then the mean weight of the drop is divided by the circumference -, then for all liquids examined this quotient is less than the capillary constant a cos0, and secondly this qnotient increases with decrease of radius of the tube.Both these statements are deducible from the previous observations of Hagen and Quincke. Again the diameter of the capillary tube determines the shape of the drop; thus with tubes of less than 3 4 mm. their form is more or leas spheroidal, with tubes of 1 mm. the form is cylindrical with a convex base, and with tubes of larger diameter it is para- boidal . V. H. V. C 2 r r Crystallisation by Diffusion. By C . E. GUIGNET (Compt. rend., 303, 8iS--875).-The experiments described in this paper are an extension of Becquerel's researches on electro-capillary reactions. The introduction of any solid into a saturated solution of another solid determines the crystallisation of the latter, provided that the solid introduced is soluble in the particular solvent.For example, solid paraffin introduced into a saturated solution of sulphur in carbon bisulphide causes the separation of crystals of sulphur, and vice versd ; sodium thiosulphate introduced into a saturated solution of ammonio-cupric sulphate yields violet needles of ammonio-cupric thiosulphate. If crystals of sodium sulphate are placed in a saturated solution of barium chloride, the crystals become opaque but retain their form, aud when the crystals are broken each one is found to be a sort of102 ABSTRACTS OF CIIEMICAL PAPERS. miniature lode with crystals of barium sulphate. Barium chloride iiitroduced into a saturated solution of sodium sulphate yields only amorphous barium sulphate, probably because the chloride dissolves too quickly.Ordinary sodium phosphate placed in magnesium sulphate solution produces crystallised magnesium phosphate. Ia order to observe these phenomena with two liquids, if the action is merely physical, a saturated solution of a solid is covered with a layer of the solvent, and on this is poured a second liquid in which the solid is somewhat less soluble than in the first. The liquids gradually mix by diffusion, and the solid separates in very distinct crystals. If a saturated solution of sulphur in carbon bisalphide is covered with a layer of the bisulphide, and on this is poured a layer of oil, alcohol, glacial acetic acid, benzene, petroleum, &c., octahedral crystals of sulphur are deposited. A saturated solution of lead chloride in hydrochloric acid covered in a similar manner with a layer of hydrochloric acid and a layer of water, yields fine crystals of lead chloride.Where chemical action takes place between the liquids, one is placed in a crgstallising dish which is 6lled nearly i~ the top, and this is placed inside another vessel which contains the second liquid. Water is then carefully poured into both dishes until it is just higher than the edge of the inner dish. Diffusion takes place through the super- natant water, and crystals are formed. Sodium snlphate and calcium chloride give long crystals of calcium sulphate ; sodium sulphate and barium chloride give crystallised barium sulphate ; sodium sulphate and lead acetate give crystals of lead sulphate ; and potassium ferro- cyanide and lead acetate yield long pale-yellow needles of lead ferro- cyanide.On a large scale, wooden vessels with a leaden partition which does not quite reach to the top are used. The liquids are poured one into each compartment, and &he latter are then tilled up with water until the water just, flows over the top of the partition. In this way very large crystals can be obtained. Influence of some Normal Salts on the Decomposition of Methyl Acetate by Hydrochloric and Sulphuric Acids. By H. TREY (J. pr. Chenz. [2], 34, 353--377).-Ostwald investigated (J. pr. Chem. [2], 23, 209) the difference in the action of acids caused by the presence of their normal salts; the author has repeated these experiments with a view to obtaining a satisfactory explanation of t h i s action. Tbe experiments were made with hydrochloric and sulphuric acids, and the salts of these acids with the alkalis and alkaline earths.The methyl acebate method was used, in the manner previously described, with normal acids ( I gram-equivalent in 1 litre) and normal acids to which 4, 4, 1, &c., equivalents of their normal salts had been added. These normal solutions were also used 29, 5, and l2g times diluted. The results were calculated according to the formulse given by Ostwald (this Journal, 1884, SSl), and are given in a series of tables. These values are not strictly comparable, but require correcting for the increase of volume caused by the addition of salt and the consequent decrease of the velocity of the reaction. The C. H. B.GENERAL AND PHYSICAL CHEMISTRY.103 mean values found are given below; the second line in each case gi yes the corrected value. 1.121 1.049 1.032 Normal . . . . . 1 - normal .. Z L 6 normal.. . . 1 - normal . . 12+ --- 1.426 1,167 1.005 Hydrochloric Acid and Alkaline Chlorides. 1 - normal . . 2 i 32 -76 32.87 11 -75 11 *82 6 -61 5 -68 2 -23 2 -24 1.000 HC1 (1 litre) t lNaCl 1 - normal. . 12.1- 36 -87 37 *49 12 '27 12 -35 5 -75 5 t85 2 -20 2 -24 1 .OOO HC1 (1 litre) t 4NaCl -- 52 -87 57 '62 13 -88 14 *88 6 -09 6 -64 2 *15 2 -34 - HCl :1 litre) + tKcL 31 -89 32 -16 11 -73 11 -83 5 *63 6-67 2 -21 2 -22 - - HCl (1 litre) + lKC1. 34 -66 35 -05 11 -89 12 -26 5 -63 5 -80 2 -15 2 -22 HCl (1 litre) + 3KU1. 40.83 44 -60 12-45 13 *64 5 -60 6 -14 2 '10 2 *30 -- Calculating the ratio in which the velocity of action of the hydro- chloric arcid is increased %y the addition of the &ove salts, the following numbers are obtained :- (1 litre).I + normal.. . . I 1 -000 - HCl (1 litre) + +N&l. 1 051 1.011 1.011 1.009 - HC1 (1 litre) + lNaCl --- 1 0199 1 -056 1 -041 1 -009 HCl (1 litre) + 4A aC1 1 '843 1 a73 1 -181 1-054 - HC1 (l. litre) + tKCl 1 *028 1 -012 1 -009 1 -000 HCl (1 litre) + 1KC1. HCl (1 litre) + 3KC1. For the stronger solutions, the increase of the action of the hydro- chloric acid is proportional to the amount of salt present; for the weaker solutions, the increase is so small as to fall within the errors of experiment. Hydrochloric acid and lithium, magnesium, calcium, strontium, and barium chlorides, gave the followiog numbers :-104 ABSTRACTS OF CHEMICAL PAPERS.Normal . . . . . + normal.. . . -- Normal .. . . 4 normal.. . . 1 *OOd 1 *961 1 '000 1 *146 56 *83 61.31 5 -97 6 -44 1.985 1.171 HCl (1 litre) + BMgCl,. 1.409 1.080 66 -56 69 -26 6 '33 6-59 HC1 (1 litre) + 2CaC1. -- 59 -43 62 *69 6 -24 6 5 6 HC1 (1 litre) + 2SrC1,. 68 *55 62 -06 6.20 6 -58 HC1 (1 litre) + 1BnC1,. 42 -46 44 -07 5 *84 6 -07 -- These numbers gave the following ratios for the accelerating action of the salts :- HC1 (1 litre) + 2MgC1,. HC1 (1 litre) + 2UaCI. HC1 HC1 (1 litre) (1 litre) + 2SrClj. + lBaCI,. 2 -215 1.173 2 *005 1 -167 From these results the author concludes that the accelerative influence of the chlorides stands in the inversive ratio to the atomic weights of the respective series. Thus, calculated for 1 equivalent of chloride, the numbers are :- .~ LiC1. 1 NaCl.1 KCE. 1 MgCk. 1- CaC1,. 1 SrC1,. 1 BaCIJ. 1.240 1 1.199 1 1.121 I 1.304 I 1.251 1 1.246 I 1.205 These results agree with those found by Reicher (Abstr, 1885, The action of eulphnric acid in the presence of normal salphates is The action is retarded to 1 equivalent salt, but in a less degree The following tables give the mean values for 1034) for the saponification of ethyl acetate by alkalis. the reverse of that of hydrochloric acid. nearly proportionally with with 2 equivalents. normal and + normal solutions :-QENERAL AND PHYSICAL CEENISTRY. #IlGrmlbl - Normal. +normal 105 3 -04 2 -68 2 -16 { 3L546 3 -04 2 -69 2 -19 -- -__I_ ------ 1.000 0.885 0 -760 0 * 578 1.000 0.910 0 -805 0 -656 frH$04 (1 litre) + )MgSO,.0.787 *HaSol (1 litre) + lNGO4. I__-- 6 8s' 7 -08 1 '62 1 -67 0 -426 0 -500 -- - &SO4 (1 litre) BH2S04 (1 litre) BH,SO, (1 litre) + +LizS04. f +Na&404. + +Kfi04. 0 -620 0 -579 0 *330 -------_I_-- With aulphuric acid, the retarding influence of the sulphates on the velocity of the action appears to inorease with the atomic weight of the elements of the series, thus :- Dithionic acid in the presence of its normal salts was in- fluenced in the same way as hydrochloric acid, so also was the bibasic methylenedisulphonic acid, whilst dichloracetic acid behaved like sulphuric acid. This method of investigation will therefore throw no light on the basicity of dithionic acid, but th0 author thinks the results show that it does not form acid salts in aqneoucil solution.Preservation of Gases over Mercury. By H. B. DIXON (Chem. News, 64, 227-228).-From the author's eqepiments, it is shown that, provided due precautions are taken t o prevent the formation of' a, film between the glass and the mercury, gases may be safely preserved over mercury for a considerable time. Cracking Glass with Certainty. By E. BECKXANN (Zeit. amE. &%em., 25, 530-531).-A scratch is made with a file ; at both sides of this, pads of wetted filter-paper are wrapped round the object,, leaving a, space of a few millirnetres between them. The flame of a Bunsen or gas blowpipe is applied to this space, when the crack will be carried round from the scratch midway between the two pads. Apparatus for Chemical Laboratories. By J. WALTER (J. PT.Chem. [23, 34, 427--432).-A new form of condenser, and flasks for use with it, both for ordinary and fractional distillation. G. H. M. D. A. L. M. J. S. G. H. M.93General and Physical Chemistry.Chemical Changes produced by Sunlight. By E. DUCLAUX(Compt. rend., 103, 881-882).-Many organic compounds are affectedhy solar radiation in the same way as by microbes, the products of thechange being water and carbonic anhydride, with other substanceswhich are relatively stable in the conditions under which tEey areproduced, and are identical with the products of the action ofmicrobes.Cane-sugar in neutral or alkaline solution is not affected by pro-longed exposure to sunlight, but if slightly acidified even with anorganic acid it is readily inverted by solar radiation.The solution ofinvert sugar undergoes no further change so long as it remains acid,but if made alkaline the glucose is rapidly decomposed with formationof water, carbonic anhydride, oxalic, formic, and acetic acids, andabout 3 per cent. of alcohol. A similar change takes place, althoughless rapidly, out of contact with the air, and hence it is evident thatthe decomposition is due to internal combustion.Lactose and lactates also yield alcohol under similar conditions.The exact nature of the change in any case is modified by the nature’of the source from which oxygen is absorbed (air, salts of platinum,gold, mercury) ; but the chief products are practically the same fromall substances. These products are alcohol, oxalic acid, acids of theacetic series, leucine, carbamide, carbonic anhydride, water, &c.Certaindifferences are, however, observed. Tartaric acid gives aldehyde inplace of alcohol, and the alcohols, if oxidation is regular, tend toproduce the corresponding acid of the acetic series.Practical Methods of Photographing the Spectrum. ByJ. M. EDER (Monatsh. Chem., 7 , 429-454) .-This paper .contains adescription of some practical methods of photographing the variousparts of the spectrum by silver bromide gelatin plates sensitised bydifferent dyes. The preparation of the plates and the processes usedfor the development are described in full, and accompanied by copiesof photographs taken.For spectra from the ultra-violet to the yellow, about D, the bestdyes are erythrosin, henzopurpurin 4B, and yuinoline-red ; from theultra-violet to the red cyanin, is the best ; from the orange to the red,ccerulein with red glass, and “sensitive green,” R dye from para-hydroxybenzaldehyde and dimethylaniline, are recommended.Theseplates, sensitive to the green, yellow, or red part of the spectrum, aresuitable for photography by petroleum and gas light, and for takingphotographs of gilded documents and papyri, of microscopic prepam-tions. and of clouds on a blue sky, interposing yellow glass to subduethe blue. Excellent photographs of stars have been taken with thaC. H. B.aid of these plates. v. H. v.VOL. LII. 94 ABSTRACTS OF CHEMICAL PAPERS.Electrolysis Of Carbon Compounds. By .T. HABERhIANN(Monntslz. Chem., 7, 529-551).-1n continuation of former experi-ments on the electrolysis of carbon compounds (Abstr., 1881,215), theauthor describes the resalts which are obtained under various con-ditions with alcohol acidified with sulphnric acid, or rendered alkalineby soda, and with potassium acetate dissolved in methyl alcohol or itshomologues.The sources of electrical energy used were a thermo-battery of 120 elements, a Smee’s battery of 16 elements, and a dynamo-machine of one horse-power.On electrolysis, alcohol acidified with sulphnric acid yields hydrogenevolved as gas at the negative pole, aldehyde, and after prolonged actionaldehyde-resin together with ethyl hydrogen sulphate. The mainreaction is therefore C2H,0 = C2H40 + H,.If the alcohol is renderedalkaline, or is in the form of sodium ethoxide, the products of decom-position are hydrogen, carbonic anhydride as sodium carbonate, analdehyde-resin insoluble in ether and alcohol, together with a solublemodification, and a subshance allied to cinnamaldehyde.A concentrated solution of potassium acetate in ethyl alcohol yieldsa mixture of hydrogen and ethane together with potassium ethylcarbonate, by the mutual decomposition of the salt and acid. In fact,the process serves as a convenient method for the preparation ofpotassium ethyl carbonate in large quantities, as the salt separates infine crystalline aggregates. It is quickly decomposed by water, butdissolves in absolute alcohol without change.The results obtained with solutions of potassium acetate in methyland butyl alcohols were unsatisfactory.V. H. V.Phosphates. By BERTHELOT (Compt. rend,, 103, 911-917).-When ammonium chloride is added to a solution of trisodinm phos-phate there is an absorption of heat which varies with the proportionof ammonium chloride, being 5.96, 5.63, 4.84, and 2.62 cal. for 3, 2, 1and 4 mols. of ammonium chloride respectively. Complete decom-pwition of the sodium phosphate would correspond with anabsorption.of heat equal to -6.4 cal., and hence it is evident thatt,he action of the ammonium chloride is almost complete, although thewater exerts a greater dissociating effect on the ammonium pbosphatethan on the sodium salt.I f trisodium phosphate is added to a solution of a magnesium,barium, strontium, calcium, or manganese salt,, a colloidal precipitate ofthe insoluble phosphate is at first formed, and there is considerableabsorption of heat, but after some minutes the precipitate becomescrystalline and a large quantity of heat is developed.The heslts offormation of the colloidal and crystallised phosphates are given in thefollowing table :-Colloidal. Crystallised.Magnesiuni hydrogen phosphate., 50.6 ,, 54.2 ,,Magnesium phosphate .......... 57.8 cal. 83.0 cal.Barium phosphate ............. 68.4 ,, 1008 ,,Strontium phosphate .......... 65.4 ,, 97.4 ,,Calcium phosphate 64.0 ,, -Manganw? phosphate .......... 45.8 ,, 53.5 ,,............ 9 GENERAL AND PHYSICAL CHEMISTRY. 95In the case of barium phosphate, the sodium phosphate must beadded to the barium chloride, and not vice uers$, otherwise the changeto the crystalline state is Loo rapid.The phenomena now describedexplain the discordant results obtained by Louguinine and the authorfor the heat of neutralisation of phosphoric acid by baryh, and also thedifferences observed by Blarez (this vol., p. 7) between the heatsof formation of barium phosphale and barium arsenate. In the caseof strontium also, the change to the crystalline condition is extremelyrapid, if the strontium solution is poured into that of the trisodiumphosphate. Calcium phosphate was obtained only in the colloidalform.The heats of formation of the collo'idal insoluble phosphates do notdiffer to any great extent from the heat of formation of an equivalentquantity of trisodium phosphate, 33.6 x 2 cak.In other words, theprecipitate in its initial condition corresponds clsseIy with the solublesalt from which it has been derived, a further example of the tendencyof systems which are undergoing transformation to preserve theirmolecular type. On the other hand, the new phosphates may bedissociated by water to a greater extent than the sorubre phosphatefrom which they have been formed; and this dissociation ail1 beaccompanied by an absorption of b a t , This absorption is practicallywil with barium phosphate, which appmximates closely to the alkalinephosphates, but ib is very cfistinct wihh magnesium phosphate, whichis more readily dissociated.In dissolved trisodium phosphate, the third and even the secondequivalents of the base are less intimately combined with the acid thanthe first atom, and are partially separated from it by the dissociatingaction of the solvent.There can be little doubt that this imperfectstate of combination also exists in- the colloidal insoluble phosphates,tlie formation of which is due b a polyalcoholic rather than an acidfunction of the phosphoric acid. The combination, however, soonbecomes more intimate, and the alcoholic function changes to an acidicfunction comparable with that 04' ordinary tribasic acids, the changebeing accompanied by development of heat, and crystallisation of thephosphates. The actual development of heat is mnch greater thancan be supposed to be due to the mere physical change from thecolldidal to the crystalline condition, even if the change wereaccompanied by eombination with water.As a matter of fact, theerystallised phosphate contains less water than the colloidal phosphate.In their new condition, the heats of formation of the insoluble phos-phabes become practically treble that of the ordinary monophosphates,or in other words, the three acid functions become equivalent to oneanother, and to this change is due the greater proportion of the heatdeveloped in the passage from ihe colloidal to the crystalline form.Heats of Neutralisation of Homologous and Isomeric Acids.By H. GAL and E. WERNER (Comyt. rend., 103, 806--809).-Theauthor has determined the heats of neutralisation of isobutyric,isopropy la ce tic, t rime thy lace tic (pivalic) , caproic, isobu tylace tic.andsorbic acids, and his results, together with the heats of neutralisationof the lower acid8 of the acetic series, as determined by Berthelot,C. H. B.h 96 ABSTRACTS OF CHEMICAL PAPERS.Lougninine, and others, are given in the following table. Heat ofsolution of isobutyric acid, directly + 0973 cal., indirectly + 1.012cal. ; isopropylacetic acid, directly + 1.167, indirectly + 1.030.Heat ofAcid. neutralisation.Formic acid, H-COOH ........................ 13.3Acetic acid, MeGOOH ........................ 13.4Propionic acid, CH,Me*COOH .................. 14.3Normal butyric acid, CHF,Me*CH2*COOH ........ 14.4Isobutyric acid, CHMe,*COOH. ................. 13.9Normal valeric acid, CH2Me*CR2*CH,*COOH...... 14.4Tsopropylacetic acid, C HMe2*C H2* C 0 OH ......... 14.4T rime thylace tic acid, CMe3*COOH .............. 13.6 74Normal caproic acid, CH,Me*CH,*CH,*UH,*COOH . 14.689Isobu tylilcetic acid, CHMe,*CH,*C 0 OH 14-5 i .......... {Omitting formic and acetic acids, the heat of neutralisation of theother acids, with the exception,of isobutyric and trimethylacetic acids,is practically constant, and varies between 14.3 and 14.6. Isobutyricacid is a secondary acid, and trimethylacetic acid is ft tertia1.y acid, andit would seem therefore that the heat of neutralisation of primary acidsis greater than that of secondary acids, whilst that of tertiary acidsis somewhat smaller atill. The heat of neutralisation of sorbic acid,which is regarded by Menschutkin as a tertiary acid, is 12.945.C.H. B.Heats of Neutralisation of Malonic, Tartronic, and MalicAcids. By H. GAL and E. WERNER (Compt. rend., 103, 871-873) .-MaZonic Acid.-Heat of solution at 10° = -4.573 cal. Heat ofneutralisation by soda : 1st equivalent, 13.342 cal, ; 2nd equivalent,13.778 cal. ; total, 27.120 cal.Heat ofneutralisation by soda : l e t equivalent, 13.71 1 cal. ; 2nd equivalent,11.856 cal. ; 3rd equivalent, 0 0 cal. ; total, 25.567.Mulic Acid.-Heat of solution at 20" = -3,148 cal. Heat o€neutralisation by soda : 1st equivalent, 12.730 cal. ; 2nd equivalent,,12.189 cal. ; 3rd equivalent, 0.0 cal. ; total, 24.919.The heat of neutralisation of oxalic acid is 28.1 cal. (Berthelot andThomsen) ; of succinic acid, 26.4 csl.(Chroutschoff) ; and tartaricacid, 25.3 cal. (Berthelot).I t is evident from these values that the heat of neiitralisationdiminishes as the molecular weight increases. The intzodnction ofthe OH group into oxalic, malonic, and succinic acids lowers the heatof neutrdisation by about 2 cal. A similar difference has previouelybeen observed between propionic and lactic acids, and between benzoicand the hydroxybenzoic acids.Themnochemistry of Reactions between Magnesium Saltsand Ammonia. By BERCHELOT (Compt. rend., 103, 844-848) .-When magnesium sulphate solution is mixed with an equivalentquantity of sodium hydroxide solution, there is an immediate develop-,Tartronic Acid.-Heat of solution at 12" = -4.331 cal.C.H. BGENERAL Ah'l) PHYSICAL CWMBTRY. 97ment of +0*18 cal., but the development of heat gradually slackma,and at the end of 10 minutes is + 1-14 cal. ThB successive develop-ments of heat are due to the fact that a basic srtlt is first formed,which is afterwards decomposed by the soda, and also to the hydra-tion, contraction, $c., of .the precipitate. Magnesium chloride m dsodium hydroxide behave in like manner. At first there is an absorp-+ion of -0.32 cal., and afterwards a development of 44-32 cal., thefinal result being nil.It is evident, &s the reseamhes of Thomsen, Favre and Silbermann,Ditjte, and othere have already indicated, that the heat developed bythe action of acids on magnesium hydroxide approximates closely tothttt developed by their action on potash and soda.The action of ammonia on magnesium sulphate is accompanied byan absorption of -0.24 cal., whereas if the magnesium were com-pletely displaced, 3.0 cal.should be absorbed. The difference is dueto the formation of double salts or oxides, the production of which isaccompanied by a development of + 2.8, cal. With magnesium chlo-ride, the difference between the calculated and observed values is+2.2 cal.If magnesium sulphate is mixed with 2 mols. of ammonium chloride,+0.32 cal. is developed, and if an equivalent quantity of ammonia i qnow added, there is a further development of +0.26 cal., the total de-velopment of +0*58 cal. being due to the formation of a complexoxide, the heat of neutralisation of which is 0.33 cal.higher than thesum of the heats of neutralisation of magnesium oxide and ammoniaseparate1.v. When magnesium chloride is mixed with ammonia, thereis an absorption of -0.48 cal., and if ammonium chloride is thenadded there is a, development of +0*56 cal., the sum being 0.08 cd.,from which it followa that the heat of neutralisation of the complexoxide by hydrochloric acid is practically identical with that of magne-aium oxide,If magnesium sulphabe OF chloride solution is mixed with sodininhydroxide, and ammonk then added, the greater part of the precipi-tate redissolves, but there k no sensible $herma1 disturbance, a resultwhich indicates that the heat of solution of the precipitate is idenficalwith its heat of combination with the solvent.If, oa the other hand,magnesium sulphafe i s first mixed with ammonia, md the sodiumhydroxide added afterwards, there is a development, a€ +Is90 cal.,probably due to the facf that, the order *of admixture being reversed,the liquid requires a much longer time to attain the same condition.The differenee betweert the observed thermal d i s t n r b c e and the de-mb ment of heat resulting fmni the action of soda or magnesiummlp!ka alone ia a, fnrther proof of the formation of complex corn-peunds.I f magnesium snlphate is mixed with 2 mals. of ammonium chlo-ride and sodium hydroxide then added, +3.64 cal. are developed,and some permanent precipitate is formed. The thermal disturbanceis greater than that which would colrwpond with the displacement ofammonium by sodium, rtnd the difference indicah the cornbination ofmagnesia and a;mmonia with formation of ammonio-magnesium sul-phate.If 4 mols. of ammonium chloride fire added at the begia9s ABSTRACTS OF CHEMICAL PAPERS,ning, no precipitate is formed, and the heat developed is +3.90 cal.JVith magnesium sulphate, the excess of heat developed above thatcorresponding with the decomposition of the ammonium salt is + 1.2 cal., with the chloride it is +1*0 cal.From these results it follows that the complex ammonio-magnesiumbases in uniting with sulphuric or hydrochloric acid, develop about + 1.8 cal. more than pure ammonia, and + 0.3 cal. mow. than magne-sium oxide. The association of ammonia with a metallic oxide suchas magnesia would seem to result in the production of a complexalkali analogous to tetramethylammonium oxide, with an energygreater than that of metallic oxides, and approaching +ha& of thestrongest alkalis.C. H. B.Heats of Combustion and Formatiun mf Homologous Phe-nols. By 3’. STOHMAKN, P. RODATZ, and H. HERZBERU (J. pr. Chem.[2], 34, 311-327).-1n this paper a series of determinations of theheats of combustion and formation of the homologous series ofphenols are given in detail, as also their heats of liquefaction. Theprincipal values obtained m e given in the following table :-Heat of combustionper gram-molecule.Phend (did), C,H,-OH. ..... .- .. 723659Orhhocresol (liquid), CsH4Me-OH. .. 883008Mehcresol (liquid) ..............880956Paracresol ................ 882900Orcinol, C6H,Me(OH), (solid). ..... 824724Orthoxylenol, C6H3.%fe2*OH (solid). . 1035434Mehxylenol (liquid). ............. 10374999 araxylenol (solid) ........ -. ..... 1035638Fseudocumenol, CBH,Me,-OH (solid) 119145 1Carvacrol, CGH3MePr*OH (liquid). . 1354819Thymol (liquid). ................. 1353750.. (liquid) ................. 726002 .. (solid). ............. 879788.. (solid) .............. 880441.. (solid) .................. 1348982Heat offormation.-509925304451100109276615665950 161362685496818169250--On a comparison of these numbers, it will be seen that every dis-g!acement of hydrogen bp a methyl-group corresponds with an incre-inent of 155356 cal.in the heat of combustion, a value praotically equalta that obtained for the homologues oE methyl alcohol. Thus it followsthat the displacement of‘ hydrogen by methyl, either in the so-calledside-chain or i n the nucleus, corresponds with the same value forthe heat-increment. Thus the value for ethylphenol will be equal t othat of xylenol. Similarly also, as the d u e s for carvacrol andthymol are approximately equal to that of pseudocumenol, namely,the introduction of the isopropyl-group produces the same effect asthat of three single methyJ groups, then the heat values of the iso-are equal to those of normal-compounds. V. H. VGENERAL AND PHYSICAL CHEIIISTKT. 99Some Laws of Chemical Combination. By DE LANDERO andR. P R r E n , (Conzpt.rend., 103,934-935).-1f chemical combination istaken as the clashing together of the particles of the elements, and ifeach particle is regarded as possessing a constant velocity which ischaracteristic of the pctrticular element, the loss of energy resultingfrom the union of the non-elastic particles may be regarded as theequivalent of the quantity of heat developed by the combination.These considerations lead to the formula-(V + T q 2 , ee'= 2(a + e')in whichf = the heat of Combination expressed in calories, e, e' = theweights of the combining elements epuivaient to 1 gram of hydrogen,whilst V and V' are quantities which a m constant for each elementand are proportional to the velocities of their particles. These quan-tities may be termed thermodynamic constants, or thermodynamiccquivdeuts, and their value is obtained by the €ormula-9 * v'=y/2f--,,.e + e'Take the ease of the two copper bromida-Cuprous bromide: e + e' = 143.4; f = 25900Cupric bromide: e + e' = 111.7; f = 17300- + 38.269cal.; V + V' =cal; v * V' =- + 39'039.Calculations with t i n bromides, mercury bromides, mercury iodides,&c., lead to similar results. Since V Ifi V' is the sum or difference ofthe thermodynamical equivalents of the two elements in each system ;i t is necessary to obtain the consfants of some of the elements fromdifferent sets of compounds, care being taken to use only thermo-chemical data referred to the solid state. The following table givesthe thermodynamical equivalents of several elements, these values re-ferring in each case to that quantity of the element which is equivalentto 1 gram of hydrogen:-K ......45221 S ...... 47.874 A1 ...... 48.218Nu.. .... 49.768 T1 ...... 5.223 Zn.. .... 13.073Hg.. .... 9.079 Ag .... 12.i86 Bb ...... 5.155B r . . .... 44.171 Cu .... 4.999 Si ...... 37.519I ....... 32.416 Ca, ..... 50.309C. H. B.The Law of Volumes in Chemistry. By T, S. HUNT (Chem.News, 54,206-207) .-The author advocates the universal applicationof the law of volumes to solids, liquids, and gases, which would renderthe application of the atomic hypothesis to explain the law of definiteproportions wholly unnecessary. From this standpoint, the union ofmany volumes of vapour or gas to form a single volume of vapour orsolid would be regarded as chemical combination; the reverse,namely raporisation, would be chemical decomposition, which wonldbe without specific difference in the case of integral volatilisation, o100 ABSTRACTS OF CHEMICAL PAPERS.with definite changes, as in cases now regarded as dissociation. Thedifference between chemical and physical molecules would hence bequite evident.D. A. L.Velocity of Dissociation. By H. LESCCEUR (Compt. rend., 103,931-933) .-The velocity of dissociation of acid sodium acetate,CzH,0zNa,2CzH40,, was determined by placing the compound in asmall bell-jar which also contained soda-lime ; the temperature of thewhole being kept a t 100". The mean velocity of dissociation duringk i given interval is determined by dividing the time into the loss ofweight of the compound.The results indicate the existence of abiacetate, CZH,O2Na,C2H1O2, and a sesquiacetate, 2C2H,02Na +Velocity of dissociation does not depend on the temperature alone,as Miiller-Erzbach siipposes, but also on the physical condition of thesubstance which is undergoing dissociation. In this particular case,the rate of dissociation increased fourfold when the acetate becttmesolid, although the tension of dissociation did not change, and similarphenomena are observed with copper sulphate crystals, &c.CzHaOz.C. H. B.Nature of Liquids. By W. RAMSAY and S. YOUNG (Ohm. News,54, 203-205).-1t is proved by various investigations that, above aeertain pressure and temperature, all liquids show an increase in thedensity of their saturated vapours beyond that deducible from themolecular formula, varying of course with the liquid.Some liquids,however, known to be dissociable, in addition show an increasealso on fall of temperature and pressure below a certain tem-perature and pressure characteristic of the liquid. Reasoning fromthese facts, the following difference is suggested between stable anddissociable liquids :-In the former, the molecules exhibit physicalbut not chemical attraction ; in the latter both pliysical and chernicalattraction are evident, inasmuch as, besides cohesion and surface ten-sion, there is evidence of molecular combination. The behaviour of.vapours at the moment the liquid is visible support this theory, forwhereas vapours from dissociable liquids continue to rise in pressure i nspite of the decrease in volume and condensation of liquid (evidenceof non-homogeneity of the vapour, owing in these instances to forma-tion of molecules of higher molecular weight), vapours from stableliquids do not behave in this manner, but the pressure in such case isthe vapour-pressure corresponding with the temperature ; hence itmay be concluded that the latter show no tendency to form complexmolecular groups.With regard to the solvent action of a fluid above its critical point,the authors have worked with a solution of eosin in alcohol, takingthe fluorescence as indicating solution.They find that solution existedat least for a short time at temperatures a little above the criticalpoint, and at volumes smaller than the critical volume ; apparently,however, after some time the solid is wholly deposited as such on thewalls of the tube.This is not conclusive, as the translucent red sub-starice deposited on the glass interfered with the detection of thefluorescence. According to the authors' view of the nature of liquidsGENERAL AND PH Y STCAL CHEMISTRY. 101solution should be possible above the critical point provided thevolume is sufficiently small. D. A. L.Capillary Constants and Meniscus Angle. By J. TKAUBE(J. pr. C'he?n. [2], 34, 292--31l).--l)eterminations are given for thevalue of the function a' cos 8 according to the formula rh = a2 cos 0, foraqueous solutions of. the alcohols of the paraffinoid series and acids ofthe acetic series at various degrees of concentration (comp.Abstr.,1885, 1033). The principal points to be noticed are that both propyland isopropyl alcohols show a minimum value for tho function withmixtures of equal weights of the alcohol with water, and that theeurve for butyric acid at first decreases with increase of concentrationup to 30 per cent., thence increases up to 50 per cent., and sub-sequently decreases.After a historical review of the literature on the magnitude ofdrops, an account is given of experiments, made with an apparatuspreviously described, permitting of the formation of drops from acapillary tube under constant or variable conditions of temperatureand pressure. The weight of the drops was ascertained by deter-minations of the specific gravity and the number of drops in aconstant volume.The results obtained with the above-mentionedalcohols and acids show that the volume of the drops is proportioual tothe rise in height in the ca~illary tube, or their weight is proportiwrd tothe product oj' the height and the specijiic gravzty. If then the meanweight of the drop is divided by the circumference -, then for allliquids examined this quotient is less than the capillary constanta cos0, and secondly this qnotient increases with decrease of radiusof the tube. Both these statements are deducible from the previousobservations of Hagen and Quincke.Again the diameter of the capillary tube determines the shapeof the drop; thus with tubes of less than 3 4 mm.their form ismore or leas spheroidal, with tubes of 1 mm. the form is cylindricalwith a convex base, and with tubes of larger diameter it is para-boidal . V. H. V.C2 r rCrystallisation by Diffusion. By C . E. GUIGNET (Compt. rend.,303, 8iS--875).-The experiments described in this paper are anextension of Becquerel's researches on electro-capillary reactions.The introduction of any solid into a saturated solution of anothersolid determines the crystallisation of the latter, provided that thesolid introduced is soluble in the particular solvent. For example,solid paraffin introduced into a saturated solution of sulphur incarbon bisulphide causes the separation of crystals of sulphur, andvice versd ; sodium thiosulphate introduced into a saturated solutionof ammonio-cupric sulphate yields violet needles of ammonio-cupricthiosulphate.If crystals of sodium sulphate are placed in a saturated solution ofbarium chloride, the crystals become opaque but retain their form,aud when the crystals are broken each one is found to be a sort o102 ABSTRACTS OF CIIEMICAL PAPERS.miniature lode with crystals of barium sulphate.Barium chlorideiiitroduced into a saturated solution of sodium sulphate yields onlyamorphous barium sulphate, probably because the chloride dissolvestoo quickly. Ordinary sodium phosphate placed in magnesiumsulphate solution produces crystallised magnesium phosphate.Ia order to observe these phenomena with two liquids, if the actionis merely physical, a saturated solution of a solid is covered with alayer of the solvent, and on this is poured a second liquid in whichthe solid is somewhat less soluble than in the first.The liquidsgradually mix by diffusion, and the solid separates in very distinctcrystals. If a saturated solution of sulphur in carbon bisalphide iscovered with a layer of the bisulphide, and on this is poured a layerof oil, alcohol, glacial acetic acid, benzene, petroleum, &c., octahedralcrystals of sulphur are deposited. A saturated solution of leadchloride in hydrochloric acid covered in a similar manner with a layerof hydrochloric acid and a layer of water, yields fine crystals of leadchloride.Where chemical action takes place between the liquids, one is placedin a crgstallising dish which is 6lled nearly i~ the top, and this isplaced inside another vessel which contains the second liquid. Wateris then carefully poured into both dishes until it is just higher thanthe edge of the inner dish.Diffusion takes place through the super-natant water, and crystals are formed. Sodium snlphate and calciumchloride give long crystals of calcium sulphate ; sodium sulphate andbarium chloride give crystallised barium sulphate ; sodium sulphateand lead acetate give crystals of lead sulphate ; and potassium ferro-cyanide and lead acetate yield long pale-yellow needles of lead ferro-cyanide.On a large scale, wooden vessels with a leaden partition which doesnot quite reach to the top are used.The liquids are poured one intoeach compartment, and &he latter are then tilled up with water untilthe water just, flows over the top of the partition. In this way verylarge crystals can be obtained.Influence of some Normal Salts on the Decomposition ofMethyl Acetate by Hydrochloric and Sulphuric Acids. By H.TREY (J. pr. Chenz. [2], 34, 353--377).-Ostwald investigated (J. pr.Chem. [2], 23, 209) the difference in the action of acids caused bythe presence of their normal salts; the author has repeated theseexperiments with a view to obtaining a satisfactory explanation oft h i s action. Tbe experiments were made with hydrochloric andsulphuric acids, and the salts of these acids with the alkalis andalkaline earths. The methyl acebate method was used, in the mannerpreviously described, with normal acids ( I gram-equivalent in 1 litre)and normal acids to which 4, 4, 1, &c., equivalents of their normalsalts had been added.These normal solutions were also used 29, 5,and l2g times diluted. The results were calculated according to theformulse given by Ostwald (this Journal, 1884, SSl), and are given in aseries of tables. These values are not strictly comparable, but requirecorrecting for the increase of volume caused by the addition of saltand the consequent decrease of the velocity of the reaction. TheC. H. BGENERAL AND PHYSICAL CHEMISTRY. 103mean values found are given below; the second line in each casegi yes the corrected value.1.1211.0491.032Normal . . .. .1 - normal .. Z L6 normal.. . .1 - normal . .12+---1.4261,1671.005Hydrochloric Acid and Alkaline Chlorides.1 - normal . .2 i32 -7632.8711 -7511 *826 -615 -682 -232 -241.000HC1(1 litre)t lNaCl1 - normal. .12.1-36 -8737 *4912 '2712 -355 -755 t852 -202 -241 .OOOHC1(1 litre)t 4NaCl--52 -8757 '6213 -8814 *886 -096 -642 *152 -34-HCl:1 litre) + tKcL31 -8932 -1611 -7311 -835 *636-672 -212 -22 --HCl(1 litre) + lKC1.34 -6635 -0511 -8912 -265 -635 -802 -152 -22HCl(1 litre) + 3KU1.40.8344 -6012-4513 *645 -606 -142 '102 *30--Calculating the ratio in which the velocity of action of the hydro-chloric arcid is increased %y the addition of the &ove salts, thefollowing numbers are obtained :-(1 litre).I+ normal.. . . I 1 -000-HCl(1 litre) + +N&l.1 0511.0111.0111.009 -HC1(1 litre) + lNaCl ---1 01991 -0561 -0411 -009HCl(1 litre) + 4A aC11 '8431 a731 -1811-054 -HC1(l. litre) + tKCl1 *0281 -0121 -0091 -000HCl(1 litre) + 1KC1.HCl(1 litre) + 3KC1.For the stronger solutions, the increase of the action of the hydro-chloric acid is proportional to the amount of salt present; for theweaker solutions, the increase is so small as to fall within the errorsof experiment.Hydrochloric acid and lithium, magnesium, calcium, strontium,and barium chlorides, gave the followiog numbers :104 ABSTRACTS OF CHEMICAL PAPERS.Normal .. . . .+ normal.. . .--Normal .. . .4 normal.. . .1 *OOd 1 *9611 '000 1 *14656 *8361.315 -976 -441.9851.171HCl(1 litre) + BMgCl,.1.4091.08066 -5669 -266 '336-59HC1(1 litre) + 2CaC1.--59 -4362 *696 -246 5 6HC1(1 litre)+ 2SrC1,.68 *5562 -066.206 -58HC1(1 litre) + 1BnC1,.42 -4644 -075 *846 -07--These numbers gave the following ratios for the accelerating actionof the salts :-HC1(1 litre) + 2MgC1,.HC1(1 litre) + 2UaCI.HC1 HC1(1 litre) (1 litre) + 2SrClj. + lBaCI,.2 -2151.1732 *0051 -167From these results the author concludes that the accelerativeinfluence of the chlorides stands in the inversive ratio to the atomicweights of the respective series. Thus, calculated for 1 equivalent ofchloride, the numbers are :-.~LiC1. 1 NaCl. 1 KCE. 1 MgCk. 1- CaC1,. 1 SrC1,. 1 BaCIJ.1.240 1 1.199 1 1.121 I 1.304 I 1.251 1 1.246 I 1.205These results agree with those found by Reicher (Abstr, 1885,The action of eulphnric acid in the presence of normal salphates isThe action is retardedto 1 equivalent salt, but in a less degreeThe following tables give the mean values for1034) for the saponification of ethyl acetate by alkalis.the reverse of that of hydrochloric acid.nearly proportionally withwith 2 equivalents.normal and + normal solutions :QENERAL AND PHYSICAL CEENISTRY.#IlGrmlbl -Normal.+normal1053 -04 2 -68 2 -16 { 3L546 3 -04 2 -69 2 -19 -- -__I_ ------1.000 0.885 0 -760 0 * 5781.000 0.910 0 -805 0 -656frH$04 (1 litre) + )MgSO,.0.787*HaSol(1 litre) + lNGO4.I__--6 8s'7 -081 '621 -670 -4260 -500---&SO4 (1 litre) BH2S04 (1 litre) BH,SO, (1 litre) + +LizS04. f +Na&404. + +Kfi04.0 -620 0 -579 0 *330-------_I_--With aulphuric acid, the retarding influence of the sulphates onthe velocity of the action appears to inorease with the atomic weightof the elements of the series, thus :-Dithionic acid in the presence of its normal salts was in-fluenced in the same way as hydrochloric acid, so also was the bibasicmethylenedisulphonic acid, whilst dichloracetic acid behaved likesulphuric acid. This method of investigation will therefore throwno light on the basicity of dithionic acid, but th0 author thinksthe results show that it does not form acid salts in aqneoucil solution.Preservation of Gases over Mercury. By H. B. DIXON (Chem.News, 64, 227-228).-From the author's eqepiments, it is shownthat, provided due precautions are taken t o prevent the formation of'a, film between the glass and the mercury, gases may be safelypreserved over mercury for a considerable time.Cracking Glass with Certainty. By E. BECKXANN (Zeit. amE.&%em., 25, 530-531).-A scratch is made with a file ; at both sidesof this, pads of wetted filter-paper are wrapped round the object,,leaving a, space of a few millirnetres between them. The flame of aBunsen or gas blowpipe is applied to this space, when the crack willbe carried round from the scratch midway between the two pads.Apparatus for Chemical Laboratories. By J. WALTER (J. PT.Chem. [23, 34, 427--432).-A new form of condenser, and flasksfor use with it, both for ordinary and fractional distillation.G. H. M.D. A. L.M. J. S.G. H. M