81 G e n e r a l a n d P h y s i c a l Chemistry. Emission Spectra of Haloi'd Mercury Compounds. By B. 0. PEIRCE (Ann. Yhys. Chenz. [el, 6, 597--,599).-The emission spectra were obtained by passing the electric current through 8 Geissler tube containing a small quantity of the salt ; wken the salt is warmed with a Bunsen burner, the mercury spectrum is seen, and as bhe heat is increased bands appear which differ according t o the salt employed. The measurements were made with a Steiihcim spectroscope, the scale of which corresponded as follows with the lines of the spectrum : Si + 81, Na - 100, Hgn, - 102.9 and 103.8, Baa - 111, Hga - 114, SrP - 157, Hgp- 176, Hg6 - 138, H ~ E - 207. When mercuric chloride was used, a band appeared a t 1084 - 1 OO$. The edge of this band was sharply defined on the less refrangible side ; but when the salt was strongly heated, a continuous spectrum was observed, stretching for some distance on the more refrangible side.Mercurous chloride gives the same band, whence it is argued that mercurous chloride is dissociated. Mercuric bromide gives st band between 131 and 135; mercuric iodide a band between 168 and 172. It is remarked that the bromide band is exactly half way between that of the chloride and that of the iodide. F. D. B. Smoke of an Electric Lamp. By B. S. PROCTOR (Chenz. News, 39, 283).-Att the Newcsstle-upon-Tyne Chemical Society Mr. J. W. Swan exhibited an electric lamp on the incandescent principle, in which the current had to pass through and heat a cylinder of carbon placed between two platinum condnctors ; this arrangement was placed in a vacuum in a glass vessel, and as the current was too strong the carbon cylinder broke down.The author examined the glass which enclosed it, and found the inside covered with a sooky deposit which, under a $-inch rnicro- scopic objective, appeared nebulous, with some bright specks of plati- num here and there. The platinurn supports were also covered with the black deposit, which burned off easily on being heated to dull redness. A piece of the glass was treated with aqua regia, and platinum and iron were found in the solution. It is possible that the platinum particles were scattered about by the disruptive discharge, which fol- Thermochemical Investigation of the Oxiaes and Acids of Nitrogen. By J. THOMSEN (Bey., 12, 2062-2065).-1n order to calculate the heat of formation of the oxides of nitrogen, the following values were determined by experiment :- lowed the breaking down of the carbon cylinder.w. T. VOL. XXXVIII.82 ABSTRACTS OF CHEMICAL PAPERS. Reaction. Heat of formation. N, + H, + 0, = NFT,NO, . . . . . . . . . . 64950 units W20, + 0, = N,O, . . . . . . . . . . . . . . . . 39140 .. N,+ O..........................--18320 .. N204 + Aq ...................... 15510 .. Oxidation of an aqueous solution of N,0+ N,04Aq + 0 = + 18320. From these data, the following results were obtained. which differ considerably from Berthelot's determinations (Ann. Phys. Chem. [ 5 ] , 6, 178) :- Berthelot. Thorn Ben. N2 + 0.. . . . . . . . . . . . . N, + O2 . . . . . . .. . . . . -86600 units - 72790 ,, N, + 0 3 + Aq.. . . . . . . -51800 ,, - 36460 ,, . . . . . . . . . . . . -33650 ,, N, + 0 4 - N, + 0, -t- Aq N2 + 0, + Aq.. -14800 ,, t 180 ,, - 18320 units - - 18140 ,, . . . . . . . . - . . . . . . The following table shows in columns I and I1 the heat of forma- tion of the anhydrous nitrates ; in I by the direct union of their elements, and in I1 according to the equation + O2 + N,O1. Column I11 shows the heat of solution of these salts:- Nitrates of I. Potassium.. .. 104660 Sodium.. ..... 96430 Iithium ..... 96800 Thallium ..... 43330 Silver . . . . . . 1.3920 Barium.. .... 196100 Strontium ... 190210 Calcium . . . . . 173590 Lead . . . . . . . . 75860 Sr 4- 0, + N,O1 4- 4H20 Ca + 0, + N,O, + 4H,O Cd + 0, + NZO, + 4H,O Mg+ 0, + N,Oa + 6H2O Zn+ 0 2 + K20J + 6H20 Ni + 0, + N,O, + 6H20 CO + 0, + NZO, + 6H10 CU+ 0, + N204 + 6H,O 11. 242960 226500 227240 120300 61480 229750 223860 207240 109510 231540 218440 124870 214530 142180 124720 123330 96950 111.- 17040 - 10060 + 600 - 19940 - 10880 - 9400 - 4620 + 3950 - 7610 - 12300 - '7250 - 5040 - 4220 - 5840 - '7470 - 4 9 0 - 10710 w. c. w. Therrnochemical Research on the Carbonates. By. J. THOMSEN (Ber., 12, 2031--2032).-The heat evolved in the formation of the following anhydrous carbonates by the combination of carbonic oxide, oxygen and the metal, is given in column I ; the heat evolved by the combination of carbonic acid with the metallic oxide is showri in column 111. For the sake of comparison the heat of formation of the corresponding anhydrous sulphates from metal, oxygen and sulphurous anhydride is given in column 11.GENERAL AND PHYSICAL CHEMISTRY.53 Carbonates and sulphntes. I. 11. 111. . K, . . . . . . . . . . . . 25OCl40 273560 257510 - - Na,:!.. . . . . . . . . . . 242490 Ba . . . . . . . . . . . . 252770 266490 5.5580 Sr . . . . . . . . . . . . 251020 2598.20 53230 CR . . . . . . . . . . . . 240660 248970 42490 Mil . . . . . . . . . . . . 180690 178790 Cd . . . . . . . . . . . . 151360 150210 Y b 139690 145130 22580 - - . . . . . . . . . . . . A g 2 . . . . . . . . . . . . 92i70 96200 20060 w. c. w. Mutual Relations of Potassium and Sodium Alum in Aqueous Solution. By F. P. VENABLES (C‘hem. Kews, 40, 198-199) .-Two forms of isomorphism between these two salts may be conceived : the formation of a double alkaline alum, KNaS04.Al,(S04),.24H20 : and the isomorphous admixture of the two alums in the various crys- tals.All attrempts to prepare the double alkaline alum failed, the isomorphous displacement always being of the second kind, tlie potas- sium salt predominating, owing to its being less soluble in water than the sodium salt. Experiments T+*ere also made on the solubility of potassium alum in R solution of sodium alum of diflerent strengths and a t different temperatures, the results being that 100 grams water containing- (;r.ams sodium alum 4.8 10.0 12.1 15~4 21.1 33.7 55.6 76.7 } i.8 6.1 5.7 5.3 4.7 3.8 2.7 1.7 Will dissolve potas- sium alum L. T. 0’s. Law of Dulong and Petit applied to Perfect Gases. By H. WILLOTTE (C’onzpt. rend., $9, 540--543).-The product AC of the mole- cular weight A into the specific heat a t constant volume C is very nearly the same for all gases.In order. therefore that any two gases may be a t the same temperature, it is necessary and sufficient that the mean total energy of any molecule whatever sball have the same value in both gases, that is to say, that AB’ = A%’’ ; A and A’ being the molecular weights of the gases nnder consideration, and --, AB2 __ A’”‘, the means of the total energies of the molecules of eachgas. Tm7o or more gases are a t the same temperature, if, when placed in contact with each other they nevertheless preserve their total respective energies unchanged. It may be shown (1) by making use of the theory of Carnot, or ( 2 ) by the homogeneity as far as velocity is concerned of the equations rela- ting to the theory of percussion, that if the rule AE2 = A’B’2 holds good for any one tcniperature, it does so for all other temperatures ; tlie question is how far this can be explained from a purely mechanical point of view.It cannot be due t o the mutual collisions of the molc- cules, for Clausius has shown t h a t inter-molecular shocks exert only a disturbing influence in the theory of gases; the author therefore prefers to explain it by molecular collisions against the atoms of a material ether, a gas of exceedingly low density, having its constituent 2 2 9 284 ABSTRACTS OF CHEMICAL PAPERS. particles situated a t distances very small in relation to the dimensions of the molecules of ordinary gases ; a supposition which serves as n basis for several theories. If A represents the weizht of any molecule endued with a rapidity of translation F1, the arithmetical mean of the quantities of move- ment representing the forces of percussion due to the displacement of the molecule A, can be reprcscnted by hzAb;?dt, the sum Z being taken during anp moment of which dt is the element, X being a constant independent of the nature of the molecule under consideration.The sum of the terms calculated for unity of time is approximatelg 2Ab;ilt = AB;, where B: is a quantity equal to the mean of b;. If in any vessel there are n molecules whose mass is equal to A, and n’ whose mass is equal to A’, the arithmetical law of the forces of per- cussion acting in unity of time on the mass of ether in question will be h(nAJ3: + n’A’B’:).Again, if while n f ‘yL‘ = const., the sum just mentioned does not vary when the composition of the mixture is altered, the systems formed by the forces of percussion will not vary either ; and again the sum will remain invariable whatever be the ratio if AB; = A’B’:. ?L With a mass of molecules whose centres of gravity are Exed, bnt of which the various parts are endowed with reciprocal movements, it may be found by similar reasoning tlint in the case of equilibrium of temperature, the energies corresponding to thcse movements satisfy the relation AR; = A’B’:, whence by addition- - - *’a representing the total mean energies of the molecules. 2 ’ 2 AB2 AB2 It is thus seen why the ratio -’ is the same for all gases at any deter- minate temperatures ; further by making use of the principle of homo- geneity before mentioned, it may be easily demonstrated that if the ratio __ is the same for all gases a t any temperature arbitrarily chosen, it will hold good, o r very nearly so, for all other temperatures, the value of the ratio varying very slowly with the temperature.(lcbid., 89, 568-570). I n determining the conditions of equilibrium of t2mperature in the case of a solid body surrounded by its own vapour, t w o principal facts have to be established : (1) the influence of the colli- sions between the molecules of the solid and those of the gas ; ( 2 ) the influence of the ether. I n the first case, on account of the equality of the masses of these molecules, these collisions, far from having a disturbing effect as in the case of a mixture of two gases, are, on the contrary, sufficient of themselves to maintain an equilibrium, if all the molecules have the same mean energy, that is to say, if the B2 of the molecules of the solid is the same as the B* of the molecules of the AB2 gas.(B2 is a quantity such that ___ represents the total mean 2 energy of a molecule whose weight is A.) AB; ABZGENERAL AND PHYSICAL CHEMISTRY. 85 As far as the ether is concerned, it is obvious that the molecnles of the solid are in the same conditions as the molecules of the gas ; if B2 has the same value in both, the total mean energy being theu tlie same, the conditions of equilibrium are determined. As an illustration, if we consider two volatile solids wholly immersed in their own vapour, the two atmospheres being separated from each other by a piston moving in a liorizontnl cylinder, when the temperature of the system is in equilibrium, the gases on each side of tlie piston satisfy the equation AJ32 =; A'B'2 , and this equality holds good equally for the solids A and A', since they have the same B2 as their respective vapours. But the equality AB' = A'Bf2 is affected by the collisions of the molecules of the gases against the walls of the cylinder and piston; this disturb- ing influence obviously diminishes with the degree of expansion of the gases, so that, a t the extreme limit, when a vacuum exists on both sides of the piston, the cause of error will disappear, and, since the piston has then become useless, it may be removed.Thelaw may, therefore, be stated as follows :-Given two simple solid bodies in a vacuum but not in contact, whose atomic weights are represented by AA', the actual energy of each of these bodies when their temperature is in equilibrium should be such as t o satisfy the equation AB2 = A'W. From the preceding it follows that the product of the atomic weight of a body by its absolute caZor~lfic cn;n?ucity (Him), is constant for all simple bodies. For compound bodies, an analogous law may be de- cluced. The product __ is the same for every substance; A being a quantity proportional to the weight of the chemical molecule under consideration ; C tlie absolute calorific capacity of the latter ; and t L the number of atoms entering into the composition of the molecule.J. VS;. Variation in the Composition of the Air. By P. v. JOLLY AC Ik (A4m. P1iy.s. Chem. [ 21, 6, 520-544) .-The analpes of air which have from time to time beer1 made exhibit slight, variations in the percentage o f oxygen. These differences might be attributed to unavoidable errors in the observations ; it appeared, however, that air collected in the same place at different times had not always the same density, and conse- quently not the same composition ; experiments were therefore under- taken to clear up any uncertainty in the matter. The composition of the air was determined by two separate methods : firstly, by observing its density ; secondly, by eudiometric analysis. In the first method, the air was weighed in a glass globe holding about a litre, and the amount of oxygen which it contained calculated I)y means of the equation- zw, + (1 - X ) W , = w, where z = vol.of 0 at 0' and 760 mm. in the unit of volume of air. JVo = weight of contents of the globe when filled with pure oxygen a t 0" and 76U min. ; Wu = weight of contents of the globe when filled with pure nitrogen a t 0" and 760 mm. ; and W = weight of contents of tlle globe when filled with the air at 0" and 760 mm. It was necessary in the first place to determine the values of VC', and The oxygen used in these determinations was obtained by the86 ABSTRACTS OF CHEMICAL PAPERS. Jan. 25 ........ Peb. 9 . . . . . . . . . . E'eb. 16 ......... Mmrch 7 ........ i\la,rch 18 ...... Way 9 . . ........ May 18 . . . .. . . . decomposition o€ water by electrolysis ; the nitrogen by passing a i r over h a t e d copper gauze, which had previously been reduced by hydrogen. It was found that the copper thus reduced retained a con- siderable amount of hydrogen, which could only be renioved by heat- ing it to a red heat in a vitcuum. The weighings were conc1uctedwit:i ;tll possible precautions against error, full details of which m e given in the paper. The mean value of W, obtained from seven experiments was 1.442515 gram, tlie probable error being .OOU013, that of W, ob- tained from the same number of' ohservations was 1.269455 gram, the probable error being _+ *000024. The larger. prolnable error in the case of nit1 ogen must be nttribu ted to the greater difficulty exlncrienced in obtaining the gas in a pure state.The samples of air, the composition of which was to be determined, mere always collected a t the same place, about 2 kilometers from the city of Xunich. The following table gives the date of collection, the direction of the wiud, and the corresponding value of W. (The experr- ments were made in1875-76) :- K.E. N.W. W. ' K.W. s. E. 15. 1 *303035 1 305754 1 *305281 1 * 303099 1 '303157 1 *305014 1,305200 1 '305131 June 7 .......... June 29.. . . . . . . . . July 1 5 . . . . . . . . . . July 22 .......... Aug. 2 . . . . . . . . . . dug. 29.. . . . . . . . . Sept. 11.. . . . . . . . . Sept. 1'7.. ........ ?V. w. N. cv. s. K.E. N.E. w. s. (?) 1 '305046 1 305307 1 *305239 1'30559 4 1.30529h 1 * 305469 1.305075 1 '304931 The greatest weight, 1.305754, was observed during a north-east wind ; the least, 1.304931, during a south wind ; in both cases the wind had blown for a considerable time in the same direction.The first value of TV corresponds to 20.965 per ccnt. of oxygen ; the second to 20.477. Before passing to the eecond method, and to the experiments maclc. by its means, the weights of a litre of oxygen and of nitrogen respec- tively were obtained from the ralues of Wn aiicl TVll given above. To (lo this it was only necessary to find tlie weight of distilled water at 4" which the glass globe would contain. This weight \\as fourid to be 1009.412 grams, the weight of a liter of oxygen in the latitude of Munich (4%" 8') and a t an altitude of 515 meters above the sea level, is therefore 1.429094 gram: that of a liter.of nitrogen in the same locality 1.257614 gram. Reducing these values to the latitude and altitude of Paris, we find that in that city 1 liter of oxygen weighs 1.4293884 gram; 1 liter of nitrogen weighs 1.2578731 gram. The numbers founq by Regnault were 1.4293802 and 1.256167 respectively ; t,he differences may be due to the diffkrences in the meights used, or to the impurity of the gases used by Regnault. The composition of the air was determined eudiometricdly by first observing the pressure of a given volume of the air a t 0" in the eudi- ometer, then absorbing the oxygen by means of a red-hot copper spiral,GENERAL AND PHYSICAL CHEMISTRY. 87 ---- heated by an electric current, and finally observing the pressure of the ~emaining nitrogen, occupying the same volume a t 0”.Determined i n this manner the percentage of oxygen is not liable to an error exceeding 0.09 per cent. The following table gives the results of experiments thus made :- I-- Date. Oxygen per cent. Jnne 13 .................... )) 18 .................... ) ) 24 .................... ) ) 27 . . . . . . . . . . . . . . . . . . . . ,) 31 .................... July 3 . . .................... ,, 17 .................... ,) 19 ..................... 20 -53 20 *95 2G ‘73 20 ‘66 20 ‘69 20 %6 20 %& 20 -56 .. 27 ..................... October 12 .................. )) 1% .................. ) ) 15 .................. )) 16 .................. ) ) 21 .................. )) 27 .................. )) 31 .................. Xorember 2 ................), 10 ................ ) ) 1 3 . . . . . . . . . . . . . . . . ) ) 2 0 . . .............. ,, 23 .................. 20 ’86 20 ‘83 20 -75 20.84 20 -84 21 -01 20 -85 20 ‘91 20 ‘56 20 .G7 1 20.65 Bar. 1 Wind. I 714’03 717 -7 716 -8 ‘718 *7 718 -1 716 9 713 -1 713 .9 719.9 713 *’i 720 *9 719 9 723 -3 723.0 710 *6 i21 5 714 *Z 724 -1 718 ‘2 707 ‘0 703 ’9 N. N.E. X.E. X.E. E. S. S.W. K.E. E. N.W. E. E. E. K . cv. S. W.E. S.E. w. K.X. . These experiments, which were made in 1877, show that the p v - centage of oxygen varied from 21.01, when the north wind blew, t o 2Us.53 during the west wind. The density of the air is therefore not a constant number. Relative Space occupied by Gases. By G. ScmrDr (An,:. Phys. Chem. [el, 6, 61?-615).-1f the molecular weight of h y d r o p i = 2, and the density of the air = 1, the molecular volume of a per- iiiaient gas is ordiiiarily set down as- V = 28.8725, it is contended that this number should be 28-8384, on the supposi- tion that the air contains 20.96 per cent.in volume of oxygen, and a table is given of the densities d of the various gases and vapours, calcu- lated by means of the formula s = - where ?I?, = the moleculny F. D. B. ?I 2 2 , ’ weight. * I?. D. B. * It i E clearly shown in the preceding nbstrart of the paper by I?. v. Jolly, that the density of tlie air is :L mrisble quantity ; the d u e of V must therefore also bt: \-ariltble, and the densities of gases cannct be expressed in terms of the density of the air.-F. L). 13.S8 ABSTRACTS OF CHEMICAL PAPERS. Absolute Expansion of Liquid and Solid Bodies.By H. F. WIEBE (Ber., 12, 1761--1764).-The force of cohesion which binds together the molecular groups in liquids and solids, is measured by the expansion which these bodies andergo under the influence of heat. The absolute expansion of an atom, i e . , the coefficient of expansion of the atomic volume, bears .a relation to the number of atoms which have combined together to form a liquid or solid group of molecules. Since all bodies have the same cohesion at their boiling and also a t their melting points, if the absolute expansion is multiplied by the temperature of these fixed points (calculated from the absolute zero), multiples of the coefficients of expansion, 0.00365, are obtained, as is shown in t'he following table :- ~ - - I.Absolute expansion for 1". I-- I- --- s ............... He .............. Zn .............. Cd .............. 8 .............. Se .............. Zn .............. C:d .............. 0.003015 0 -001872 0 -000795 0 -001188 0 -003015 0 *OolS72 0 400795 0 *001188 11. B. p. C ~ C U - lsted from absolute zero. 772 975 1315 1135 m. p. 388.6 492.0 687 *O 690 *o Product of I x 11. ~- 2 -1'7688 1 32520 1 *0454.25 1.348380 1.171629 0.921024 0 *5 %61& 0 '700920 Coe5cient of expansion. m. 0.003628 x 600 0.00365 x 500 0.003485 x 300 0'003371 x 400 0903905 x 300 0*003607 x 250 0.003641 x 150 0*003505 x 200 When n equals'the atomic weight,, d the density, a: the mean coeffi- cient of expansion between the melting and boiling points, T the tem- perature of the boiling or melting point (above the absolute zero), and /3 the coefficient of expansion in the gaseous state ; then - - T = 6.~2.I n this equation nz bears a relation to the number of atoms in the liquid or solid molecule. The author has investigated homologous series of organic compounds, and obtained the following results :- aa: d --- Formic acid ........ Acetic acid.. ........ Butpic acid ........ Methyl alcohol ...... Ethyl alcohol. ....... Amy1 alcohol.. ...... I. Mean absolute expansion (between b. p. and m. p.) for 2" 11. B p. cnlcu- lated from absolute 0" 0 .O 5326 0 .om28 0 .lo235 0.05000 0.07143 0.12500 375 .o 392 -3 421 '0 341 -3 353 -3 406.8 111. Product of I x 11. I V 5.2 x 3 5.2 x 5 5.2 x 9 8.5 x 2 8.5 x 3 8 . 5 x 6 For the acids, the product of the mean absolute expansion f o r 1"INORGANIC CHEMISTRY.89 by the boiling point is equal to the constant 5.2 mnltiplied by the number of hydrogen atoms contained in the gaseous molecule, + 1. For the alcohols the constant 8.5 is multiplied by half the number of hydrogen atoms in the molecule. w. c. w. Diffusion Experiments with Acid Solutions of Mixtures of Salts. By F. HINTCBEGGER (Ber., 12, 1619-1626). --Experiments with mixtures of sulphuric acid and potassium-hydrogen sulphate, and of the latter and potassium sulphate, which were diffused into water, show that the acid diffuses more quickly than the acid salt, and the latter more quickly than the neutral salt. The same was found to be the case with oxalic acid and potassium aiid sodium oxalates ; after a time, however, this rela%ionship is reversed.Monosodic and disodic l)hosphates gave a result similar to tliat exhibited by oxalic acid. At first the monosodic phosphate diffuses more quickly, and after some time the disodic phosphate diffuses more rapidly. Hippuric acid diffuses more slowly than sodium hippurate, which is accounted for by the fact that the latter is more soluble tlian the former. P. P. B.81G e n e r a l a n d P h y s i c a l Chemistry.Emission Spectra of Haloi'd Mercury Compounds. By B. 0.PEIRCE (Ann. Yhys. Chenz. [el, 6, 597--,599).-The emission spectrawere obtained by passing the electric current through 8 Geissler tubecontaining a small quantity of the salt ; wken the salt is warmed witha Bunsen burner, the mercury spectrum is seen, and as bhe heat isincreased bands appear which differ according t o the salt employed.The measurements were made with a Steiihcim spectroscope, thescale of which corresponded as follows with the lines of the spectrum :Si + 81, Na - 100, Hgn, - 102.9 and 103.8, Baa - 111, Hga - 114,SrP - 157, Hgp- 176, Hg6 - 138, H ~ E - 207.When mercuric chloride was used, a band appeared a t 1084 - 1 OO$.The edge of this band was sharply defined on the less refrangible side ;but when the salt was strongly heated, a continuous spectrum wasobserved, stretching for some distance on the more refrangible side.Mercurous chloride gives the same band, whence it is argued thatmercurous chloride is dissociated.Mercuric bromide gives st band between 131 and 135; mercuriciodide a band between 168 and 172.It is remarked that the bromideband is exactly half way between that of the chloride and that ofthe iodide. F. D. B.Smoke of an Electric Lamp. By B. S. PROCTOR (Chenz. News,39, 283).-Att the Newcsstle-upon-Tyne Chemical Society Mr. J. W.Swan exhibited an electric lamp on the incandescent principle, inwhich the current had to pass through and heat a cylinder of carbonplaced between two platinum condnctors ; this arrangement wasplaced in a vacuum in a glass vessel, and as the current was too strongthe carbon cylinder broke down.The author examined the glass which enclosed it, and found theinside covered with a sooky deposit which, under a $-inch rnicro-scopic objective, appeared nebulous, with some bright specks of plati-num here and there. The platinurn supports were also covered with theblack deposit, which burned off easily on being heated to dull redness.A piece of the glass was treated with aqua regia, and platinum andiron were found in the solution.It is possible that the platinumparticles were scattered about by the disruptive discharge, which fol-Thermochemical Investigation of the Oxiaes and Acids ofNitrogen. By J. THOMSEN (Bey., 12, 2062-2065).-1n order tocalculate the heat of formation of the oxides of nitrogen, the followingvalues were determined by experiment :-lowed the breaking down of the carbon cylinder. w. T.VOL. XXXVIII82 ABSTRACTS OF CHEMICAL PAPERS.Reaction. Heat of formation.N, + H, + 0, = NFT,NO, .. . . . . . . . . 64950 unitsW20, + 0, = N,O, . . . . . . . . . . . . . . . . 39140 ..N,+ O..........................--18320 .. N204 + Aq ...................... 15510 ..Oxidation of an aqueous solution of N,0+ N,04Aq + 0 = + 18320.From these data, the following results were obtained. which differconsiderably from Berthelot's determinations (Ann. Phys. Chem. [ 5 ] ,6, 178) :-Berthelot. Thorn Ben.N2 + 0.. . . . . . . . . . . . .N, + O2 . . . . . . . . . . . . -86600 units - 72790 ,,N, + 0 3 + Aq.. . . . . . . -51800 ,, - 36460 ,,. . . . . . . . . . . . -33650 ,, N, + 0 4 -N, + 0, -t- AqN2 + 0, + Aq.. -14800 ,, t 180 ,,- 18320 units -- 18140 ,, . . . . . . . . -. . . . . .The following table shows in columns I and I1 the heat of forma-tion of the anhydrous nitrates ; in I by the direct union of theirelements, and in I1 according to the equation + O2 + N,O1.Column I11 shows the heat of solution of these salts:-Nitrates of I.Potassium.... 104660Sodium.. ..... 96430Iithium ..... 96800Thallium ..... 43330Silver . . . . . . 1.3920Barium.. .... 196100Strontium ... 190210Calcium . . . . . 173590Lead . . . . . . . . 75860Sr 4- 0, + N,O1 4- 4H20Ca + 0, + N,O, + 4H,OCd + 0, + NZO, + 4H,OMg+ 0, + N,Oa + 6H2OZn+ 0 2 + K20J + 6H20Ni + 0, + N,O, + 6H20CO + 0, + NZO, + 6H10CU+ 0, + N204 + 6H,O11.2429602265002272401203006148022975022386020724010951023154021844012487021453014218012472012333096950111.- 17040- 10060 + 600- 19940- 10880- 9400- 4620 + 3950- 7610- 12300- '7250- 5040- 4220- 5840- '7470- 4 9 0- 10710w.c. w.Therrnochemical Research on the Carbonates. By. J.THOMSEN (Ber., 12, 2031--2032).-The heat evolved in the formationof the following anhydrous carbonates by the combination of carbonicoxide, oxygen and the metal, is given in column I ; the heat evolvedby the combination of carbonic acid with the metallic oxide is showriin column 111. For the sake of comparison the heat of formationof the corresponding anhydrous sulphates from metal, oxygen andsulphurous anhydride is given in column 11GENERAL AND PHYSICAL CHEMISTRY. 53Carbonates andsulphntes. I. 11. 111. . K, . . . . . . . . . . . . 25OCl40 273560257510 --Na,:!... . . . . . . . . . 242490Ba . . . . . . . . . . . . 252770 266490 5.5580Sr . . . . . . . . . . . . 251020 2598.20 53230CR . . . . . . . . . . . . 240660 248970 42490Mil . . . . . . . . . . . . 180690 178790Cd . . . . . . . . . . . . 151360 150210Y b 139690 145130 22580--. . . . . . . . . . . .A g 2 . . . . . . . . . . . . 92i70 96200 20060 w. c. w.Mutual Relations of Potassium and Sodium Alum in AqueousSolution. By F. P. VENABLES (C‘hem. Kews, 40, 198-199) .-Twoforms of isomorphism between these two salts may be conceived :the formation of a double alkaline alum, KNaS04.Al,(S04),.24H20 :and the isomorphous admixture of the two alums in the various crys-tals. All attrempts to prepare the double alkaline alum failed, theisomorphous displacement always being of the second kind, tlie potas-sium salt predominating, owing to its being less soluble in water thanthe sodium salt.Experiments T+*ere also made on the solubility ofpotassium alum in R solution of sodium alum of diflerent strengthsand a t different temperatures, the results being that 100 grams watercontaining-(;r.ams sodium alum 4.8 10.0 12.1 15~4 21.1 33.7 55.6 76.7 } i.8 6.1 5.7 5.3 4.7 3.8 2.7 1.7 Will dissolve potas-sium alumL. T. 0’s.Law of Dulong and Petit applied to Perfect Gases. By H.WILLOTTE (C’onzpt. rend., $9, 540--543).-The product AC of the mole-cular weight A into the specific heat a t constant volume C is very nearlythe same for all gases. In order. therefore that any two gases may be a tthe same temperature, it is necessary and sufficient that the mean totalenergy of any molecule whatever sball have the same value in bothgases, that is to say, that AB’ = A%’’ ; A and A’ being the molecularweights of the gases nnder consideration, and --, AB2 __ A’”‘, the meansof the total energies of the molecules of eachgas. Tm7o or more gasesare a t the same temperature, if, when placed in contact with each otherthey nevertheless preserve their total respective energies unchanged.It may be shown (1) by making use of the theory of Carnot, or ( 2 ) bythe homogeneity as far as velocity is concerned of the equations rela-ting to the theory of percussion, that if the rule AE2 = A’B’2 holdsgood for any one tcniperature, it does so for all other temperatures ;tlie question is how far this can be explained from a purely mechanicalpoint of view.It cannot be due t o the mutual collisions of the molc-cules, for Clausius has shown t h a t inter-molecular shocks exert only adisturbing influence in the theory of gases; the author thereforeprefers to explain it by molecular collisions against the atoms of amaterial ether, a gas of exceedingly low density, having its constituent2 29 84 ABSTRACTS OF CHEMICAL PAPERS.particles situated a t distances very small in relation to the dimensionsof the molecules of ordinary gases ; a supposition which serves as nbasis for several theories.If A represents the weizht of any molecule endued with a rapidityof translation F1, the arithmetical mean of the quantities of move-ment representing the forces of percussion due to the displacement ofthe molecule A, can be reprcscnted by hzAb;?dt, the sum Z being takenduring anp moment of which dt is the element, X being a constantindependent of the nature of the molecule under consideration.Thesum of the terms calculated for unity of time is approximatelg2Ab;ilt = AB;, where B: is a quantity equal to the mean of b;.If in any vessel there are n molecules whose mass is equal to A, andn’ whose mass is equal to A’, the arithmetical law of the forces of per-cussion acting in unity of time on the mass of ether in question willbe h(nAJ3: + n’A’B’:). Again, if while n f ‘yL‘ = const., the sum justmentioned does not vary when the composition of the mixture isaltered, the systems formed by the forces of percussion will not varyeither ; and again the sum will remain invariable whatever be theratio if AB; = A’B’:.?LWith a mass of molecules whose centres of gravity are Exed, bnt ofwhich the various parts are endowed with reciprocal movements, itmay be found by similar reasoning tlint in the case of equilibrium oftemperature, the energies corresponding to thcse movements satisfythe relation AR; = A’B’:, whence by addition-- - *’a representing the total mean energies of the molecules.2 ’ 2AB2AB2It is thus seen why the ratio -’ is the same for all gases at any deter-minate temperatures ; further by making use of the principle of homo-geneity before mentioned, it may be easily demonstrated that ifthe ratio __ is the same for all gases a t any temperature arbitrarilychosen, it will hold good, o r very nearly so, for all other temperatures,the value of the ratio varying very slowly with the temperature.(lcbid., 89, 568-570).I n determining the conditions of equilibrium oft2mperature in the case of a solid body surrounded by its own vapour,t w o principal facts have to be established : (1) the influence of the colli-sions between the molecules of the solid and those of the gas ; ( 2 ) theinfluence of the ether. I n the first case, on account of the equality ofthe masses of these molecules, these collisions, far from having adisturbing effect as in the case of a mixture of two gases, are, on thecontrary, sufficient of themselves to maintain an equilibrium, if all themolecules have the same mean energy, that is to say, if the B2 of themolecules of the solid is the same as the B* of the molecules of theAB2 gas.(B2 is a quantity such that ___ represents the total mean2energy of a molecule whose weight is A.)AB;ABGENERAL AND PHYSICAL CHEMISTRY. 85As far as the ether is concerned, it is obvious that the molecnles of thesolid are in the same conditions as the molecules of the gas ; if B2 hasthe same value in both, the total mean energy being theu tlie same, theconditions of equilibrium are determined. As an illustration, if weconsider two volatile solids wholly immersed in their own vapour, thetwo atmospheres being separated from each other by a piston movingin a liorizontnl cylinder, when the temperature of the system is inequilibrium, the gases on each side of tlie piston satisfy the equationAJ32 =; A'B'2 , and this equality holds good equally for the solids A andA', since they have the same B2 as their respective vapours.Butthe equality AB' = A'Bf2 is affected by the collisions of the moleculesof the gases against the walls of the cylinder and piston; this disturb-ing influence obviously diminishes with the degree of expansion of thegases, so that, a t the extreme limit, when a vacuum exists on both sidesof the piston, the cause of error will disappear, and, since the pistonhas then become useless, it may be removed. Thelaw may, therefore,be stated as follows :-Given two simple solid bodies in a vacuum butnot in contact, whose atomic weights are represented by AA', theactual energy of each of these bodies when their temperature is inequilibrium should be such as t o satisfy the equation AB2 = A'W.From the preceding it follows that the product of the atomic weightof a body by its absolute caZor~lfic cn;n?ucity (Him), is constant for allsimple bodies.For compound bodies, an analogous law may be de-cluced. The product __ is the same for every substance; A beinga quantity proportional to the weight of the chemical molecule underconsideration ; C tlie absolute calorific capacity of the latter ; and t Lthe number of atoms entering into the composition of the molecule.J. VS;.Variation in the Composition of the Air. By P. v. JOLLYACIk(A4m. P1iy.s.Chem. [ 21, 6, 520-544) .-The analpes of air which havefrom time to time beer1 made exhibit slight, variations in the percentageo f oxygen. These differences might be attributed to unavoidable errorsin the observations ; it appeared, however, that air collected in the sameplace at different times had not always the same density, and conse-quently not the same composition ; experiments were therefore under-taken to clear up any uncertainty in the matter.The composition of the air was determined by two separate methods :firstly, by observing its density ; secondly, by eudiometric analysis.In the first method, the air was weighed in a glass globe holdingabout a litre, and the amount of oxygen which it contained calculatedI)y means of the equation-zw, + (1 - X ) W , = w,where z = vol.of 0 at 0' and 760 mm. in the unit of volume of air.JVo = weight of contents of the globe when filled with pure oxygena t 0" and 76U min. ; Wu = weight of contents of the globe when filledwith pure nitrogen a t 0" and 760 mm. ; and W = weight of contentsof tlle globe when filled with the air at 0" and 760 mm.It was necessary in the first place to determine the values of VC', andThe oxygen used in these determinations was obtained by th86 ABSTRACTS OF CHEMICAL PAPERS.Jan. 25 ........Peb. 9 . . . . . . . . . .E'eb. 16 .........Mmrch 7 ........i\la,rch 18 ......Way 9 . . ........May 18 . . . . . . . .decomposition o€ water by electrolysis ; the nitrogen by passing a i rover h a t e d copper gauze, which had previously been reduced byhydrogen.It was found that the copper thus reduced retained a con-siderable amount of hydrogen, which could only be renioved by heat-ing it to a red heat in a vitcuum. The weighings were conc1uctedwit:i;tll possible precautions against error, full details of which m e given inthe paper.The mean value of W, obtained from seven experiments was1.442515 gram, tlie probable error being .OOU013, that of W, ob-tained from the same number of' ohservations was 1.269455 gram, theprobable error being _+ *000024. The larger. prolnable error in the caseof nit1 ogen must be nttribu ted to the greater difficulty exlncrienced inobtaining the gas in a pure state.The samples of air, the composition of which was to be determined,mere always collected a t the same place, about 2 kilometers from thecity of Xunich.The following table gives the date of collection, thedirection of the wiud, and the corresponding value of W. (The experr-ments were made in1875-76) :-K.E.N.W.W.' K.W. s.E.15.1 *3030351 3057541 *3052811 * 3030991 '3031571 *3050141,3052001 '305131June 7 ..........June 29.. . . . . . . . .July 1 5 . . . . . . . . . .July 22 ..........Aug. 2 . . . . . . . . . .dug. 29.. . . . . . . . .Sept. 11.. . . . . . . . .Sept. 1'7.. ........?V. w.N. cv.s.K.E.N.E. w.s. (?)1 '3050461 3053071 *3052391'30559 41.30529h1 * 3054691.3050751 '304931The greatest weight, 1.305754, was observed during a north-eastwind ; the least, 1.304931, during a south wind ; in both cases the windhad blown for a considerable time in the same direction.The firstvalue of TV corresponds to 20.965 per ccnt. of oxygen ; the second to20.477.Before passing to the eecond method, and to the experiments maclc.by its means, the weights of a litre of oxygen and of nitrogen respec-tively were obtained from the ralues of Wn aiicl TVll given above. To(lo this it was only necessary to find tlie weight of distilled water at4" which the glass globe would contain. This weight \\as fourid tobe 1009.412 grams, the weight of a liter of oxygen in the latitude ofMunich (4%" 8') and a t an altitude of 515 meters above the sea level,is therefore 1.429094 gram: that of a liter.of nitrogen in the samelocality 1.257614 gram. Reducing these values to the latitude andaltitude of Paris, we find that in that city 1 liter of oxygen weighs1.4293884 gram; 1 liter of nitrogen weighs 1.2578731 gram. Thenumbers founq by Regnault were 1.4293802 and 1.256167 respectively ;t,he differences may be due to the diffkrences in the meights used, or tothe impurity of the gases used by Regnault.The composition of the air was determined eudiometricdly by firstobserving the pressure of a given volume of the air a t 0" in the eudi-ometer, then absorbing the oxygen by means of a red-hot copper spiralGENERAL AND PHYSICAL CHEMISTRY. 87----heated by an electric current, and finally observing the pressure of the~emaining nitrogen, occupying the same volume a t 0”. Determinedi n this manner the percentage of oxygen is not liable to an errorexceeding 0.09 per cent.The following table gives the results of experiments thus made :-I--Date.Oxygenper cent.Jnne 13 ....................)) 18 ....................) ) 24 ....................) ) 27 . . . . . . . . . . . . . . . . . . . .,) 31 ....................July 3 . . ....................,, 17 ....................,) 19 .....................20 -5320 *952G ‘7320 ‘6620 ‘6920 %620 %&20 -56 .. 27 .....................October 12 ..................)) 1% ..................) ) 15 ..................)) 16 ..................) ) 21 ..................)) 27 ..................)) 31 ..................Xorember 2 ................), 10 ................) ) 1 3 .. . . . . . . . . . . . . . .) ) 2 0 . . ..............,, 23 ..................20 ’8620 ‘8320 -7520.8420 -8421 -0120 -8520 ‘9120 ‘5620 .G7 1 20.65Bar. 1 Wind.I714’03717 -7716 -8‘718 *7718 -1716 9713 -1713 .9719.9713 *’i720 *9719 9723 -3723.0710 *6i21 5714 *Z724 -1718 ‘2707 ‘0703 ’9N.N.E.X.E.X.E.E.S.S.W.K.E.E.N.W.E.E.E.K . cv.S.W.E.S.E. w.K.X..These experiments, which were made in 1877, show that the p v -centage of oxygen varied from 21.01, when the north wind blew, t o2Us.53 during the west wind.The density of the air is therefore not a constant number.Relative Space occupied by Gases.By G. ScmrDr (An,:.Phys. Chem. [el, 6, 61?-615).-1f the molecular weight of h y d r o p i= 2, and the density of the air = 1, the molecular volume of a per-iiiaient gas is ordiiiarily set down as-V = 28.8725,it is contended that this number should be 28-8384, on the supposi-tion that the air contains 20.96 per cent. in volume of oxygen, and atable is given of the densities d of the various gases and vapours, calcu-lated by means of the formula s = - where ?I?, = the moleculnyF. D. B.?I 22 , ’weight. * I?. D. B.* It i E clearly shown in the preceding nbstrart of the paper by I?. v. Jolly, thatthe density of tlie air is :L mrisble quantity ; the d u e of V must therefore also bt:\-ariltble, and the densities of gases cannct be expressed in terms of the densityof the air.-F.L). 13S8 ABSTRACTS OF CHEMICAL PAPERS.Absolute Expansion of Liquid and Solid Bodies. By H.F. WIEBE (Ber., 12, 1761--1764).-The force of cohesion which bindstogether the molecular groups in liquids and solids, is measured by theexpansion which these bodies andergo under the influence of heat.The absolute expansion of an atom, i e . , the coefficient of expansion ofthe atomic volume, bears .a relation to the number of atoms whichhave combined together to form a liquid or solid group of molecules.Since all bodies have the same cohesion at their boiling and also a ttheir melting points, if the absolute expansion is multiplied by thetemperature of these fixed points (calculated from the absolute zero),multiples of the coefficients of expansion, 0.00365, are obtained, as isshown in t'he following table :-~ - -I.Absoluteexpansionfor 1".I--I- ---s ...............He ..............Zn ..............Cd ..............8 ..............Se ..............Zn ..............C:d ..............0.0030150 -0018720 -0007950 -0011880 -0030150 *OolS720 4007950 *00118811.B.p. C ~ C U -lsted fromabsolute zero.77297513151135m. p.388.6492.0687 *O690 *oProduct ofI x 11.~-2 -1'76881 325201 *0454.251.3483801.1716290.9210240 *5 %61&0 '700920Coe5cientof expansion. m.0.003628 x 6000.00365 x 5000.003485 x 3000'003371 x 4000903905 x 3000*003607 x 2500.003641 x 1500*003505 x 200When n equals'the atomic weight,, d the density, a: the mean coeffi-cient of expansion between the melting and boiling points, T the tem-perature of the boiling or melting point (above the absolute zero), and/3 the coefficient of expansion in the gaseous state ; then - - T = 6.~2.I n this equation nz bears a relation to the number of atoms in the liquidor solid molecule.The author has investigated homologous series of organic compounds,and obtained the following results :-aa:d---Formic acid ........Acetic acid.. ........Butpic acid ........Methyl alcohol ......Ethyl alcohol. .......Amy1 alcohol.. ......I.Mean absoluteexpansion (betweenb. p. and m. p.) for 2"11.B p. cnlcu-lated fromabsolute 0"0 .O 53260 .om280 .lo2350.050000.071430.12500375 .o392 -3421 '0341 -3353 -3406.8111.Productof I x 11.I V5.2 x 35.2 x 55.2 x 98.5 x 28.5 x 38 . 5 x 6For the acids, the product of the mean absolute expansion f o r 1INORGANIC CHEMISTRY. 89by the boiling point is equal to the constant 5.2 mnltiplied by thenumber of hydrogen atoms contained in the gaseous molecule, + 1.For the alcohols the constant 8.5 is multiplied by half the number ofhydrogen atoms in the molecule. w. c. w.Diffusion Experiments with Acid Solutions of Mixtures ofSalts. By F. HINTCBEGGER (Ber., 12, 1619-1626). --Experimentswith mixtures of sulphuric acid and potassium-hydrogen sulphate, andof the latter and potassium sulphate, which were diffused into water,show that the acid diffuses more quickly than the acid salt, and thelatter more quickly than the neutral salt. The same was found to bethe case with oxalic acid and potassium aiid sodium oxalates ; after atime, however, this rela%ionship is reversed. Monosodic and disodicl)hosphates gave a result similar to tliat exhibited by oxalic acid. Atfirst the monosodic phosphate diffuses more quickly, and after sometime the disodic phosphate diffuses more rapidly. Hippuric aciddiffuses more slowly than sodium hippurate, which is accounted forby the fact that the latter is more soluble tlian the former.P. P. B