137 G e n e r a l a n d P h y s i c a l Chemistry. Observations on the Solar Spectrum. By LANGLET (Compf. rend., 95, 482 - 487). - Tho observations were made on Mount Whitney, which is almost as high a s Mont Blanc, and overlooks the dryest and most deserted district of South California. 0 bservations of the total solar radiation were made with the spectro-bolometer, and also with Pouillet’s heliometer, and Violle’s actinometer. The calcu- lations are not yet completed, but the author obtains a value of about 3 cal. ; in other words, if the terrestrial atmosphere were removed, the sun’s rays would raise the temperature of 1 gram of water through 3” C. for every square centimeter of earth’s surface exposed under normal conditions. This number is higher than that obtained by Pouillet (1.7 cal.), or by Sdret, or Crova, and Violle (2-2-2.5 cal.).The author has already shown that Pouillet’s formula is only appli- cable to homogeneous rays, and gives results too low. On Mount Whitney, and also a t the Alleghany Observatory, the author has examined both with a prism and with a diffraction grating the distribution of energy in the spectrum from X 3,500 to h. 28,000. The length of the ultra-red portion of the spectrum is much greater than was supposed. If the terrestrial atmosphere were entirely removed, this portion of the spectrum would doubtless extend much further, whilst the ultra-violet portion would not be affected to any- thing like the same extent, there being but little terrestrial absorption in this region. The actual results obtained with the prism and with the grating are given in the form of two curves. One-fourth of the total energy is situated in the visible and ultra-violet portion of the spectrum, the remaining three-fourths being in the ultra-red region. I n the latter region, there are several broad absorption-bands or cold spaces, probably made up of a number of lines which are not separated by the bolometer. In the visible spectrum, the maximum energy is in the orange, Contrary to the usual opinion, theauthor finds that in a dry climate the general terrestrial absorption diminishes up to the extreme infra- red.I n both the terrestrial and solar atmospheres absorption in- creases as the wave-lengths diminish. Combining, by means of Maxwell’s discs, the coiours which would be visible a t the surface of the photosphere if all intervening absorbing layers were removed, it is found that the true colour of the photosphere is similar to that of the spectrum near F, i.e., blue.C. El. B. Absorption Spectrum of the Earth’s Atmosphere. By EGOROFF (Compt. rend., 95, 447--449).--The electric light a t Moiit ValBrien, 10 kilos. distant, was observed at the Paris Observatory by means of a spectroscope with two Thollon’s prisms attached to the VOL. YLLV. 1138 ABSTRACTS O F CHEMICAL PAPERS. Foucault telescope. The brilliant spectrum thus obtained was crossed by a large number of absorption lines. Four could easily be distin- guished between I) and D2, and on either side of D, but especially on the less refrangible side, they are very numerous and distinct.The group a is almost complete, and the region of C contains a large number of lines. B is partially resolved into eleven pairs separated by equal distances, and A can be easily distinguished by using a cobalt glass. All the groups are characteristic and easily distin- guished. With a Drummond light, a t a distance of 1600 meters, B, a, and A could be clearly distinguished, between B and a there were two faint nebulous lines, and traces of absorption lines could be seen between L) and C. With a Drummond light, a t a distance of 240 meters, the only lines visible were : A very distinct, and a very feeble, but apparent,ly intensified by a heavy shower of rain. When the light was 80 meters from the end of the telescope, A could still be seen, although with difficulty ; all the other lines had disappeared.Reflection of Actinic Rays : Influence of the Reflecting Surface. By DE CHARDOXNET (Compt. rend., 95, 449-451).-The author has photographed the spectrum of sunlight reflected from the surfaces of a large number of substances, including white and black enamel, uranium glass, crude hematite, polished hematite, diamond, compressed carbon both rough and polished, vermilion, gold, lead, nickel, Arcet’s alloy, copper, polished steel and rough steel, Prussian blue, green leaves, speculum metal, mercury, and mercury covered with a plate of quartz. His results show that there is no selective absorption, precisely the same spectrum being obtained in all cases. Silver a t first appears to be an exception, because it becomes trans- parent to the second half of the ultra-violet ; but with suficiently long exposure this part of the spectrum also becomes distinctly visible.I n this case it is better to push the exposure to the first degree of inversion pointed out by Janssen. A positive impression is thus obtained in the neighbourhood of H, and a negative in the neighbour- hood of P. Similar results were obtained with a number of liquids, including water, solution of magenta, quinine acetosulphate, ammonio-copper sulphate, potassium dichromate, milk, and ink. The author contiyms the statement of Cornu that platinum mirrors, speculum metal, and mercury covered with quartz, do not absorb any of the more refrangi- ble rays radiated from the sun. With regard to the visible rays, the author arrives a t the following conclusions. Every surface reflects in varying proportion all the rays of the spectrum ; pure colours can conseqnently never be obtained by reflection.The reflecting power of a liquid is independent of the substances which i t holds in solution or in suspension. This law apparently holds good for solid media,for a mirror of black enamel gave the same spectrum as a mirror of white enamel. It is not necessary to conclude that the incident rays do not penetrate into the reflecting surface to a depth comparable with the wave-lzngtlis. These lengt,hs would be too small to produce appreciable absorption. A layer of C. H. B.GENERAL AND PHYSICAL CHEUISTRY. 139 quinine acetosulphate showing Newton’s rings (yellow of the first and blue of the second order) has no absorptive effect on the solar spectrum.The same substance gives the same reflection whether rough or polished: the polished surfnce increases the total quantity of reflected rays, but the relative intensity of different regions of the spectrum, i.e., the actznic colour of the substance, depends on the nature of the substance employed. Widening of the Lines in the Hydrogen Spectrum. By D. v. MONCKHOVEN (Compt. rend., 95, 378--38l).-The author employed a, vacuum tube in the shape of a capital H, the horizontal part being a capillary tube 0.5 mm. in diameter, whilst tlhe vertical limbs were wider and were provided a t each end with an electrode, of which there were consequently two pairs. Under varying degrees of pressure, and with induction coils of different power, he found that the widening of bhe hydrogen lines begins a t different pressures, but always at the point where the silent discharge passes into a spark discharge.Under con- stant pressure, variations in temperature obtained by using different coils, produced no effect on the width of the hydrogzn lines. When the current from a powerful coil is passed through a hydrogen tube under low pressure for one minute, the temperature rises considerably but t8he lines remain narrow. If, however, the coil is connected with a Leyden jar, the gas is scarcely warmed, but the lines C and F are broad. If the current from an induction coil connected with a Leyden jar is passed through the tube previously described, the tube being filled with hydrogen a t a pressure of 1-2 mm., the hydrogen lines are broad. If now a current from a powerful coil is passed through the tube, by means of the other pair of electrodes, the lines do not thicken, but a bright fine line is seen down the centre of each broad line; in other words two spectra are superposed.Since the use of vacuum tubes and disruptive discharges gave no satisfactory proof as to whether the widening of the hydrogen lines is due to pressure or to temperature, the author passed an electric arc, obtained from a con- tinuous current, through pure hydrogen contained in a tube connected with a Sprengel pump. At atmospheric pressure the hydrogen lines, C and F, are seen on the continuous spectrum of the incandescent carbon particles, F is considerably widened, C less so.The lines are uniformly brilliant, and have an appearance identical with that of the hydrogen lines in the sun and some stars; whereas in the vacuum tubes the widened lines decrease in brilliancy from the centre to the edges. At 0.25 m., the width of the lines C and F decrease, and a t 0.09 m. they are almost narrow, H.1 is invisible, but the arc arid the lines increase Considerably in brilliancy. At 0.02 m., C and F are quite narrow and very brilliant, and Hp/ becomes visible. At 0.008 m., H y becomes still more brilliant. By varying the distance between the electrodes, or by altering the power of the current, the temperature was made to vary considerably, but the breadth of t)he lines always remaoined the same. The author therefore concludes that the widening of the lines in the spectrum of hydrogen i s d u e solely topre+sure and is nbso lutely independent oj’ teniperatzcre.C. H. B. C. H. B. 1 2140 ABSTRACTS O F CHEMICAL PAPERS. Spectrum of Water. By G. D. LIVEIXG and J. DEWAR (Proc. Roy. Xoc., 33, 274--276).-This paper is illustrative of a photograph of the spectrum of an oxyhydrogen flame ; in no cases were lines of a wave-length less than X 2200 observed. Influence of Temperature on the Spectra of Non-metals. By D. v. MONCKHOVEN (Comnpt. r e d , 95, 520-522) .-Plucker has shown that most of the non-metals give two perfectly distinct spectra, one of which he regards as being due to a high, the other to a low temperature. If the H-shaped tube with four electrodes, previously described (preceding page), is filled with oxygen or some other non-metal, and the gas is subjected t,o the simultaneous action of two currents, one from an induction-coil alone, the other from a coil con- nected with a Leyden jar, the high temperature spectrum and the low temperature spectrum are seen superposed.According to Plucker’s hypothesis, the gas must therefore be at two different temperatures at the same instant, a supposition which is inadmissible. The superposi- tion of the two spectra is not due to the fact that the contact breakers of the two coils do n o t vibrate in unison, thus producing alteriiations of the two spectra which appear to be superposed, owing to the per- Ristence of the images, for in some tubes, especially if the tube be filled with oxygen, the light is radiated for several tenths of a second after the current is interrupted.The author attributes the changes in the spectra of the non-metals to a particular siate of vibration of their molecules, depending directly on the nature of the electricity employed. A hydrogen vacuum tube subjected to the action of ordinary sparks presents an appearance very different from that produced by induction sparks. The stratification in a vacuum tube changes entirely accord- i n g as it is produced by ordinary sparks, by induction sparks, or by a battery of high tension. Further, each variation in the appearance of an incandescent gas (ie., change of stratification, alterat,ion of the colour of the light emitted, &c.) always corresponds with a partial, often an entire, change in the character of the spectrum, the effect being certainly independent of the temperature. Note by Abstractor.-The author’s supposition that the change in the spectra of the non-metals is due to a particular form of molecular vibration, depending on the nature of the electricity employed, is sup- ported by Schuster’s observation of the peculiar spectrum of oxygen in the neighbourhood of the negative pole.V. H. V. C. H. B. C. H. 13. Circular Polarisation of Quartz. By J. L. SORET and E. SAKASIN (Compt. rend., 95, 635-638) .-In continuing their rasearches, the authors have adopted the folloairig improved method of determining the original plane of polarisation. Between the polariser and the analyser is placed a first quartz plate, say I~evogyrate, of thickness E, a black band is brought into coincidence with a line in the spectrum, and the position of the analyser noted.The first quartz being left in position, a second quartz is added of inverse rotation, and of a, thickness equal to 2E. The general appearance of the spectrum is not modified in the least, but there is a, rotation t o the right equal to 2Eg5 degrees, where q denotes the angle of rotation forGENERAL AND PHYSICAL CHEMISTRY. 141 a thickness of 1 mm. A black band is brought into coincidence with the same spectral line, and from the angle through tv hich it is necessary to tarn the analyser, plus a certain multiple of 180", the value of @ is deduced. The results obtained by this method agree with those previously published. A table is given of the values of the angle of rotation for different rays at 20°, deduced from observations on two pieces of quartz, one 30 mm., the other GO mm.thick. The observed values agree closely with those calculated by Boltzmann's formula reduced to its two first terms, 7.1082930 + 0.1477086 @ = 1 ( ~ 6 ~ % 1 ( ~ 1 ; 2 ~ 4 ' k being the length in millimeters of the wave in air, and this for- mula may be used to calculate the angle of rotation of a ray of any wave-length between A and 0. For rays more refrangible than 0, the formula no longer holds good, even though three or four terms of the series are taken. By substituting I, the wave-length in quartz, for A, the wave-length in air, a formula is obtained, which when reduced to two terms, approximately represents the observed rotation throughout the entire spectrum. The agreement between the observed and calculated values is not, however, complete, and the differences are greater than errors of observation would be.No better results are obtained by using three terms. By addition of a third term, H6, the divergence usually becomes greater. The influence of temperature on the rotation is not constant for all rays, as is generally supposed, but increases with the refrangibility. For line 24 of cadmium, the formula for correction between 0' and 20' is @ = Go (1 + OW0179t). This coefficient is greater than the number 0*000149 obtained by several observers as the mean coefficient between 0" and 100" for sodium light, and is, of course, still greater than the coefficient for the same light between 0" and 20".C. H. B. The Metallic Galvanic Circuit of Ayrton and Perry. By B. J. GOOSSENS (Ann. Phys. Chem. [a], 16, 551--554).-According to Perry and Ayrton (Proc. Roy. ec., 27, 219) a galvanic circuit is obtained by dipping strips of platinum and magnesium into mercury, but they were unable to obtain a similar effect with other metals. The author shows that the current obtained as above by Ayrton and Perry is a true thermo-current, caused by the evolution of heat in the formation of the magnesium amalgam (cotnpare Obach, Pogg. -4nn., SupyL., 7, 300). T. C. By J. ELSTER and H. GERTEL (Ann. P ~ I J S . Chem. i2] , 16, 193--222).--The longitudinal polarisation of flame is only.appare~xt, and is caused by the unequal immersion of the mire3 serviiig as electrodes.I n its cross section, however, the flame appears t o be strongly polarised, the electrode in the zone of sir immediately surrounding the flame being always positive towards the one in the flame. The electromotive power is independent of the size of the flame. The change in the polnritly of the flame may be produced by a suitable shifting of the electrodes. The electromotive force of the Electricity of Flame.142 ABSTRACTS OF CHEMICAL PAPERS. flame is dependent ofi the nature of the metals used as electrodes, and on the nature of the burning gas. It is especially great with elec- trodes of aluminium or zinc, and very weak if the electrode situated in the surrounding zone of air is covered with a salt, such as potassium chloride. An undoubted electrical action is obtained by the use of water electrodes and exclusion of metals, the electrode in the air being positive towards that in the flame.Flames may be comhined like galvanic elements, and a number of them may be united so as to form a flame battery. The following theory is advanced in explanation of the above facts. Free electricity is not produced within the flame during combustion ; but the gases from the flame, and the zone of air surrounding the flame, have the property in contact with met& or liquids, of exciting t,he latter like an electrolyte ; and in addition to this there is a thermoelectric excitement determined by the glow- ing condition of the electrodes. This being so, the amount and nature of the electric excitement is independent of the size of the flame, but dependent on the nature and superficial condition of the electrodes, on the nature of the burning gases, and on the glowing condition of the electrodes.These conclusions have been confirmed by numerous experiments. The authors conclude therefore that Hankel’s (Pogg. Ann., 81, 212) theory as to the electricity of flames is incorrect. T. c. Electrolysis of Hydrochloric Acid. By n. TomiAsI (Con@. rend., 95, 689-691) .-With platinum electrodes and concentrated acid, the positive electrode is attacked by the chlorine, and conse- quently behaves as a soluble electrode ; with dilute acid, on the other hand, chlorine compounds are liberated a t the positive pole, but the platinum is not attacked. Conce&ated Acid-The decomposition of 2 mols.of hydrochloric acid in solution absorbs 78.6 cals., but since the positive electrode is attacked, the heat of formation of platinum chloride must be sub- tracted from this number. The electromotive force necessary to effect decomposition is consequently much less than 78.6 cals. A single Daniel1 element is indeed sufficient to produce very slow de- composition, but a Daiiiell element (49 cals.) and a zinc-cadmium element (16.6 cals.) decompose the acid rapidly, with liberation of hydrogen at the negative pole, but no liberation of gas a t the positive pole, After 20 hours, the evolution of gas continues a t the negative pole only. With two Daniel1 elements (98 cals.) decomposition is very rapid. At first there is no evolution cf gas a t the positive electrode, but after about a n hour bubbles of gas begin to form.After 20 hours, decomposition continues with evolution of hydrogen at the negative and oxides of chlorine a t the positive pole. Similar results are obtained with acid of different degrees of concentration, but the limit is reached with acid of 10 per’ cent., when the amount of platinum dissolved is very small. Dilute Acid.-On closing the circuit, gas is evolved a t the negative pole, whilst the liquid round the positive pole becomes coloured faintly yellow, and bleaches litmus- paper. Even after continuous passage of the current for 100 hours, no trace of platinum is dissolved.GENERAL AND PHYSICAL CHEMISTRY. 143 Similar results were obtained with acid of different strengths down to 1 per cent. The chlorine appears a t the positive pole in the form of oxides of chlorine, wit>h probably hypoc Ldorous acid, and perhaps traces of free chlorine.Whether the oxides of chlorine are produced by the decomposition of the hydrate HCI,GH,O, or by the action of the oxygen of the water on the hydrochloric acid, cannot be ascertained. Distribution of Heat in the Ultra-red Region of the Solar Spectrum. By P. DESAIXS (Con2pt. Tend., 95, 433--436).-The author has continued his measurements of the distribution of heat in that portion of the solar spectrum less refrangible than the red (Abstr., 1879, 854), using respectively flint glass and crown glass prisms with a refracting angle of 60". In the following hble d and d' indicate in minutes the angular distance of the cold band from the line D, i and i' the relative intensities of the bands.I t must not be assumed, however, that the inten4ty of the band at 15' from D with a crown glass prism is equal to that of the band at 42' from D with it flint glass prism. Crown Glass (Jd!j l l t h , 12th, 13th, 1881). i. 20.0 19.0 22 26.6 23.5 17.0 19.0 d. 60.5 80.5 92 117.4 127.4 147.0 i. 15.0 5.5 10 - 2.5 - C. H. B. d. 15.0 18 0 24 31.0 34.5 444.5 5Q.5 Flint Glass (July 17512, 19th, 1881). d'. 42 45.0 55 58.0 68.0 73 77.2 82 88 92.5 96 i f . 20 18.0 1 6 23.0 26.5 24 25.0 24 16 20.0 16 d'. 100 103.0 108 122.0 130.0 148 157.0 170 175 185.0 i'. 25 21.5 26 16.5 20.0 6 15.5 7 2 - With prisms of flint and crown glass, the spectrum extends t o a much greater distance beyond the extreme red than with a prism of rock salt. With rock salt, the limit is only 80' from the extreme red, whilst with flint glass it extends as far as 1" 40'.C. H. R. Law of Thermal Constants of Substitution. By D. TOMMASI (Cornpt. Tend., 95, 453--456).-It has been stated that the author's law (Abstr., 1882, 12-57) does not hold good in the case of soluble salts formed by weak acids. He therefore cites a number of examples to show that wherever the calculated number differs from that actually obtained, the difference is due to the dissociation which takes place on solution, the coefl-icient of dissociation of the particular substance not being the same as that of the corresponding potassium salt. The close agreement between the calculated and actual numbers in the case of sodium, ammonium, lithium, strontium, and calcium sulphides sllows that the coefficient of dissociation of these compounds is the same as that of potassium sulphide.The difference between the numbers found and calculated is considerable in the case of ammonium carbonate and ammonium phenate, where also the dissociation is con-144 ABSTRACTS OF CHEMICAL PAPERS. siderably greater than that of the potassium compounds. For the Eame reason there is a considerable difference between the two numbers in the case of mercuric cyanide. C. H. B. Law of Cooling. By C. R ~ T I ~ R E (Compt. rend., 95, 452-453.- The radiating body was a platinum wire heated by means of an electric current. The temperature was calculated from variations in its conductivity, and the quantity of heat lost was calculat,ed by Joule's law.Under the low pressures a t which the experiments were made, the cooling effect due to the gas present becomes of consider- able importance. The quantity of heat carried off by the air under a pressure of 0.12 mm. of mercury is given approximately in the follow- ing table :- Heat radiated in a vacuum. A 200 .................... 10 times. A 400 .................... 3 ,, A 600 .................... 1 ,, A 800 .................... 3 9 ) A 1000 4 ,) - 1 .................... With a, platinum thread 0.1 TTIM. diameter placed horizontally in a glass cylinder 0.17 mm. in diameter, and surrounded by air under a pressure of less than 0.0001 mni. of mercury, the cylinder being cooled by a current of cold water, t,he following numbers were obtained :- Temperature of the cylinder 17.3". Excess.50" 100 150 200 250 300 400 500 600 700 800 900 1000 Heat lost. 38.5 94.8 175.6 284.0 448.0 708.0 16lO*O 3300.0 6035.0 10160*0 15980.0 241 10.0 34800.0 mae (at - 1). 38.4 94.7 177-4 298.7 476.7 738.0 1684.0 3721.0 8107.0 17552.0 37891.0 81688.0 176006.0 aT2 (T - 0). 35.4 93.0 177.6 293% 445.7 638.0 11 64.0 1907.0 2904.0 4193.0 58C8.0 7788.0 10168-0 The values in the third and fourth columns are calculated from the formulm of Dulong and Petit, and of Rosetti respectively, the constants being obtained from an experiment in which the excess of the temperature of the wire was 136.3" above that of the surrounding space. These results afiord further proof of the fact that the numbers given by Dulong and Petit's formula increase far too rapidly.C. H. B. Comparison of Mercurial Thermometers with the Hydrogen Thermometer. By J. M. CRAFTS (Compt. rend., 95, 836-839).-QENERAL AND PHYSICAL CHEMISTRY. 145 The table of corrections for mercurial thermometers, which is to be found in ordinary text-books, was compiled 30 years ago by Regnault, but that experimenter himself pointed out that owing to the great variation in the composition of glass, errors might arise from the application of his tables to all mercurial thermometers. Regnault's instruments have been destroyed, and the manufactory in which they were made has ceased to exist ; moreover the composition of the glass now used in France differs very considerably from that of the glass used by Regnault. The author has therefore undertaken a revision of the table.The boiling of water a t different pressures gives the means of determining accurately temperatures between 80" and 150". Between 140" and 350" the author uses naphthalene and benzophenone a t varying pressures. He has described elsewhere the methods used for determining with the aid of a hydrogen thermometer the exact pressures corresponding to any given boiling points of these liquids. By tabulating these results, he obtains hhe pressure under which it is necessary to boil either liquid to maintain for any required time a constant temperature. By these means, he has compared 15 ther- mometers with hydrogen thermometers. Two sets of seven of these thermometers were of flint glass, by two different French makers, and the other of soda glass, by a German maker.A table* showing the amount of error of the mercurial thermometers for temperatures from 110-330" accompanies the paper. The same table gives the com- parison of these errors with those given by Regnault. The results have been confirmed by experiments with twelve other thermometers of peculiar construction. E. H. R. Limit of the Liquid State. By J. B. HANNAY (Proc. Roy. Xoc., 33, 294-321) .-A continuation of the author's researches (Abstr., 1882, 268). After some remarks on the uncertainty of our knowledge of the exact condition of a fluid immediately above and below its critical point, the author proceeds to divide fluids into three classes- (1) l i p i d s , which exhibit surface tension, as capilla,rity or a permanent limiting surface; ( 2 ) gases, which cannot be reduced to liquids by pressure alone ; and ( 3 ) ucrpours, which can be so reduced.A further distinction of gases and vapours lies in the fact that the curve repre- senting pressure and volume of a gas is a continuous straight line, whereas a part of the curve representing pressure and volunie of a vapour is asymptotic. The author proposes to show that the gaseous state is entirely dependent on the mean velocity, and not on the free path of the molecule. Numerous experiments were made to ascertain the critical temperature and pressure of alcohol under its own vapour, and under that of certain gases, as hydrogen and nitrogen. which do not attack and are not dissolved by the alcohol. A modified form of Andrews's apparatus was used.The manometers were filled with hydro- gen, as the only gas which follows Boyle's law at high pressures, and the alcohol was carefully purified by an elaborate method. T'he mean of over 100 experiments gave a critical point for alcohol * The author has informed the editor that there is a misprint in the table in the original ; the letters B and C should be transposeJ.--C. 4. G.146 ABSTRACTS O F CHENICAL PAPERS. nnder its own vapour of 235.47" under a pressure of 67.07 atmo- spheres. In order to study the critical temperature of alcohol nnder greater pressures, hydrogen was introduced over the alcohol, in order t o allow of the limiting surface of the liquid to be seen; but it was found that the crit,ical temperature was practically unaltered, even under a pressure of 178.8 atmospheres.Similar results were obtained when nitrogen was substituted for hydrogen. The method of measur- ing the capillary height of a liquid under various temperatures and pressures was also tried, and it was shown that the capillary height of a liquid is lowered by a gas under pressure impinging on its surface ; this phenomenon would follow naturally from a constant distnrbance of the surface of the liquid, owing to the high velocity of the hydro- gen molecules striking it. Capi1larit.y is not then a true measure of the cohesion of a fluid, for were the pressure sufficiently high, the surface of the liyuid might be made to disappear while its interior was in a truly liquid condition. Similar experiments were made with carbon bisulphide and tetra- chloride and with methyl alcohol, the same general results being ob- tained. The critical point of carbon bisulphide under its own vapour was found to be 277.68" at 78.14 atmospheres ; under hydrogen, 274.93" a t 171.54 atmospheres ; under nitrogen, 273.12" a t 141.45 atmospheres ; this last result is probably affected by the solubility of the nitrogen in the carbon bisulphide.The capillary action of this liquid is also weakened by a gas impinging upon its surface. Determinations of the critical point of methyl alcohol under its own vapour gave the following results:--232*76" at a pressure of 72.55 atmospheres ; under hydrogen 230.14" at 128.60 atmospheres ; and uuder nitrogen, 277.92" at 191.40 atmospheres, or 225.82" at 262 atmospheres. With carbon tetrachloride, the results were 28251" a t 57.57 atmospheres under the pressure of its own vapour, and 277.5t;O at 142.82 atmospheres under nitrogen.It was found impossible to use hydrogen, for it attacked the tetrachloride, with formation of chlo- roform, and other compounds. I n conclusion, the author views the four states of matter thus :-lst, the gaseous, which exists from the highest temperature down to an isothermal passing through the critical point, and depending on temperature or molecular velocity ; 2nd, the vaporous, bounded on the upper aide by the gaseous, and on the lower by absolute zero, and dependent, upon the length of the mean free path of the molecule; 3rd, the liquid, bounded on the upper side by the gaseous, and on the lower by the solid state; 4th, the solid. The gaseous state is thus the only one which is not affected by pressure alone, or in which the molecular velocity is so high that the collisions cause a rebound of sufficient energy to prevent grouping.Another distinction between the gaseous and vaporous states lies in the fact t'hat t>he former is capable of acting as a solvent of solids (Abstr., 1382, 271). V. H. V. By W. SPRING (Bey., 15, 1940--1945).-Between 0" and 100" the expansions of ammonium and rubidium sulphates are sensibly equal, potassium chromate only expands at a slightly greater rate, but in the case of potassium sulphate Expansion of Isomorphous Salts.GENERAL AND PHYSICAL CHEMISTRY. 147 the expansion is about 10 per cent. greater. The discrepancy is explained by the fact that a given volume of potassium sulphnte con- tains a larger number of molecules than the other salts, for on dividing the sp.gr. by the molecular weight of each salt there is obtained : K,S04 : *015316; Am2S04 : *013664 ; Rb,S04:*013657 ; K2Cr04 : .01412. Taking the ratio of the molecules of K2S0, to Am2SO4, there is obtained 0.015316 + 0.013664 = 1.21, whilst the ratio of the expan- sions of the same two salts is about the same figure, 0.012645 + 0.011191 = 1.29. E’rorn these results, i t is probable that the expan- sions of the alums are not absolutely the same, although the differences fall within the limits of error (cf. Spring, Abstr., 1882, 1020 ; Petter- son, Abstr., 1882, 1259). Modification of the Usual Statement of the Law of Iso- morphism.By D. KLEIN (Conzpt. rend., 95, 781--784).-Mitscher- lich stated the law of isomorphism as follows:-1. Two bodies are called iPomorphous when, having the same crystalline form, they can crystallise together in the same crystal. 2. Isomorphous bodies have an analogous chemical composition. The author girea in the order of their discovery certain exceptions to the second part of this law. He goes ou to state that in previous communications he has described a t uiigstoboric acid, 9WOJ,B203,2H20 + 22Aq, isornorphoics with lSlarignac’s octohedral silicotungstic acid, 12W0,,Si02,4H20 + 29Aq ; also a monosodium tungstoborate, 9\VO:{, B,O,,Na,O + 23 Aq, iso- n ~ o r p k o ~ s with the acids just mentioned ; and further a diammonium tungstoborate, 9W0,,B,0,,2NK40 + 19Aq, isomorphous with an ammonium metatungstate described by Marignac, and a dibariiim tungstoborate, 9W03,BL03,2Ba0 + 18Aq, isomorphous with the cor- responding metatungstate, The author states that the tungstoboric acid employed by him contained only a trace of silica, and that his analyses have in this respect been confirmed by Mnrignac.In con- sequence of these facts, a modification of Mitscherlich’s law has become necessary, and the author therefore gives the following, already pro- posed by Marignac, as a substitute tor the second part of the law in question :-Isomory?~ozcs bodies haue eitlier a siinilay clfemical cornposition, or possess only a slightly diferent perceutage comnposition, avid a1 1 coutain either a common group of eleinerhts or groups of elements qf iclenticul cliertiicw fuILctiows, which form by far the gyeater part of’ their weight.Observations on Crystallisation. By G. BR~~GELXANN ( B e r . , 15, 1833--1839).-After giving a short account of the deveiopment of the theories of isomorphism, dimorphism, &c., with special reference to their bearing on chemical composition, the author proceeds to show a t some length that crystallisation of two sulnstauces in the same form or tlie same crystal does not always depend on any relation in their chemical composition, a fact which has already beell pointed out in several instances, notably by G. Rose, in the case of sodium nitrate and calcspar. The examples brought forward by tbeauthor are copper sulphate and potassium dichromate, copper sulphate and cobalt chlo- ride, borax and potassium chlorate ; in most cases the cold saturated solutions were mixed in varying proportions, but in some crystals of the A.J . (3. R. H. R.148 ABSTRACTS O F CHEMICAL PAPERS. one substance were introduced into saturated solutions of the other. In all cases coloured solutions were used, and perfect co-crystallisation was observed, the colours being different, in various parts of the same crystal. Compounds therefore of the most dissimilar atomic constitu- tion can crystallise together, their power of so doine; being a function of the physical conditions in which they are found, and not of their chemical composition. The occurrence therefore of a body in a definite crystalline form is no criterion of its individuality, and the conception of isomorphism possesses only a nominal significance, as it cannot be used as a separate means of classificat,ion, but only in confirmation of facts otherwise obtained.J. I(. C. Experiments in Crystallisstion Exemplifying Berthollet’s Law of Affinity. By G. BXUGELMANN (Bey., 15, 1840--1841).-The following experiments are of interest as touching Berthollet’s law, that a liquid in which two salts have been dissolved contains the acids and bases of each reciprocally combined. Equal volumes of cold saturated solutions of cobalt chloride and nickel sulphate were mixed and allowed to evaporate spontaneously ; the crystals obtained consisted of both metals in the forrn of sulphates, and the chlorides of the two metals were left in solution. Similar results mere obtained with copper sul- phste and cobalt chloride, as well as with copper sulphate and potas- sium dichromate ; in the former case, the first crop of crystals contained both metals as sulphates, together with small quantities of chlorides ; in the latter, crystals of the mixed sulphates of copper and potassium were first deposited, then various mixtures of tlie chromates and sulphates, and finally a mixture of chromates of tlie two metals.In every case the crystallisation seems to have proceeded in a liquid con- taining four different salts. Nature of the Vibratory Movements which accompany the Propagation of Flame in Mixtures of Combustible Gases. Abstr., 1881, 971).-The authors employed a tube 3 meters long and 0 03 meter in diameter. The combustible gas was a mixture of nitric oxide and vapour of carbon bisulphjde.An image of the tube was thrown on to a, cylinder covered with sensitive paper and rotating with a known velocity. The photographs show that the flame travels at first with a uniform velocity, but afterwards performs a series of very rapid osciilations, the regularity, duration, and amplitude of which vary a t different parts of the tube. Uniform motion cothinixes with a velocity of 1.10 meter per second to a distance of 0.75 meter from the mouth of the tube. Beyond this point the flame, and con- sequently the mass of gas, is thrown into vibration, the vibrations being both simple and compound. The points a t which the vibration is simple are generally spaces of one or two-fifteenths the length of the tube. The duration of successive vibrations varies between 0.025 and 0.0034 of a second. The durations are in the simple ratios of 1, 2, 3, 4, 5, 6, but no relations could be traced between these times and the position of the flame in the tube.As a matter of fact, the vibrating mass of gas is composed of two distinct columns, one of burnt gas, the other of cold gas, the lengths and densities of which J. K. C. By AlALLARD and LE CHaTELIER (Co???pt. rend., 95, 599-560 ; see alsoINORGANIC CHEMISTRY. 149 vary a t every instant. The amplitude appears to be greatest for vibrations of long period, and is particularly great in the last third of the tube, a t the poiiit where one of the vibrating segments is situated when the tube gives the first harmonic from its fundamental note.The amplitude a t this point is as high as 1-10 meter. Since the oscillations of the flame are simply those of layers of burning gas, these experiments gave the first precise idea of the amplitude of the vibrations of a mass of gas emitting a sound. These vibratory move- ments necessarily correspond with high pressures. From calculations bssed on the variation in volunie, measured by the oscillation of the flame, it is found that the mean pressure is a t Ieast five atmospheres, and for mixtures in which the initial velocity is greater than 1 meter, the pressures will be considerably higher. The mean velocity of pro- pagation appears to increase with the amplitude and rapidity of the vibrations. I n one experiment, the limits were 1.10 meter and 5.40 meters, in anotber, 0.97 meter and 8.60 meters.I n another experiment, the explosive wave was formed a t a distance of two-thirds the length of the tube from the mouth, Le., a t the point where the amplitude of vibration was greatest, and the last third of the tube was completely shattered. The brilliancy of the flame varies a t successive phases of the same vibration, being greater when the flame moves forward than when it moves backward ; these differences increase wit'h the amplitude of vibration, and are undoubtedly connected with variations in pressure. With a tube 0.01 meter in diameter, the flame is extinguished a t a distance of about 1.5 meter from the mouth. The vibratory move.. ment is produced at a distance of 0.18 meter from the mouth of the tube, instead of at 0.75 meter. and tthe amplitude of vibration increases more rapidly.The mean velocity of propagation is at first very small, but attains a rate of 4.50 meters per second a t a distance of 0.5 meter, and becomes almost nothing just. before the extinction of the flame. The narrowing of the tube favours the development of the vibratory motion with all its consequences, C. H. B.137G e n e r a l a n d P h y s i c a l Chemistry.Observations on the Solar Spectrum. By LANGLET (Compf.rend., 95, 482 - 487). - Tho observations were made on MountWhitney, which is almost as high a s Mont Blanc, and overlooks thedryest and most deserted district of South California. 0 bservationsof the total solar radiation were made with the spectro-bolometer, andalso with Pouillet’s heliometer, and Violle’s actinometer.The calcu-lations are not yet completed, but the author obtains a value of about3 cal. ; in other words, if the terrestrial atmosphere were removed,the sun’s rays would raise the temperature of 1 gram of water through3” C. for every square centimeter of earth’s surface exposed undernormal conditions. This number is higher than that obtained byPouillet (1.7 cal.), or by Sdret, or Crova, and Violle (2-2-2.5 cal.).The author has already shown that Pouillet’s formula is only appli-cable to homogeneous rays, and gives results too low.On Mount Whitney, and also a t the Alleghany Observatory, theauthor has examined both with a prism and with a diffraction gratingthe distribution of energy in the spectrum from X 3,500 to h.28,000.The length of the ultra-red portion of the spectrum is much greaterthan was supposed. If the terrestrial atmosphere were entirelyremoved, this portion of the spectrum would doubtless extend muchfurther, whilst the ultra-violet portion would not be affected to any-thing like the same extent, there being but little terrestrial absorptionin this region. The actual results obtained with the prism and withthe grating are given in the form of two curves. One-fourth of thetotal energy is situated in the visible and ultra-violet portion of thespectrum, the remaining three-fourths being in the ultra-red region.I n the latter region, there are several broad absorption-bands or coldspaces, probably made up of a number of lines which are not separatedby the bolometer.In the visible spectrum, the maximum energy is inthe orange,Contrary to the usual opinion, theauthor finds that in a dry climatethe general terrestrial absorption diminishes up to the extreme infra-red. I n both the terrestrial and solar atmospheres absorption in-creases as the wave-lengths diminish. Combining, by means ofMaxwell’s discs, the coiours which would be visible a t the surface ofthe photosphere if all intervening absorbing layers were removed, it isfound that the true colour of the photosphere is similar to that of thespectrum near F, i.e., blue. C. El. B.Absorption Spectrum of the Earth’s Atmosphere. ByEGOROFF (Compt. rend., 95, 447--449).--The electric light a t MoiitValBrien, 10 kilos.distant, was observed at the Paris Observatory bymeans of a spectroscope with two Thollon’s prisms attached to theVOL. YLLV. 138 ABSTRACTS O F CHEMICAL PAPERS.Foucault telescope. The brilliant spectrum thus obtained was crossedby a large number of absorption lines. Four could easily be distin-guished between I) and D2, and on either side of D, but especially onthe less refrangible side, they are very numerous and distinct. Thegroup a is almost complete, and the region of C contains a largenumber of lines. B is partially resolved into eleven pairs separatedby equal distances, and A can be easily distinguished by using acobalt glass. All the groups are characteristic and easily distin-guished.With a Drummond light, a t a distance of 1600 meters, B, a, and Acould be clearly distinguished, between B and a there were two faintnebulous lines, and traces of absorption lines could be seen between L)and C.With a Drummond light, a t a distance of 240 meters, the onlylines visible were : A very distinct, and a very feeble, but apparent,lyintensified by a heavy shower of rain. When the light was 80 metersfrom the end of the telescope, A could still be seen, although withdifficulty ; all the other lines had disappeared.Reflection of Actinic Rays : Influence of the ReflectingSurface. By DE CHARDOXNET (Compt. rend., 95, 449-451).-Theauthor has photographed the spectrum of sunlight reflected from thesurfaces of a large number of substances, including white and blackenamel, uranium glass, crude hematite, polished hematite, diamond,compressed carbon both rough and polished, vermilion, gold, lead,nickel, Arcet’s alloy, copper, polished steel and rough steel, Prussianblue, green leaves, speculum metal, mercury, and mercury coveredwith a plate of quartz. His results show that there is no selectiveabsorption, precisely the same spectrum being obtained in all cases.Silver a t first appears to be an exception, because it becomes trans-parent to the second half of the ultra-violet ; but with suficientlylong exposure this part of the spectrum also becomes distinctly visible.I n this case it is better to push the exposure to the first degree ofinversion pointed out by Janssen.A positive impression is thusobtained in the neighbourhood of H, and a negative in the neighbour-hood of P.Similar results were obtained with a number of liquids, includingwater, solution of magenta, quinine acetosulphate, ammonio-coppersulphate, potassium dichromate, milk, and ink.The author contiymsthe statement of Cornu that platinum mirrors, speculum metal, andmercury covered with quartz, do not absorb any of the more refrangi-ble rays radiated from the sun.With regard to the visible rays, the author arrives a t the followingconclusions. Every surface reflects in varying proportion all the raysof the spectrum ; pure colours can conseqnently never be obtained byreflection. The reflecting power of a liquid is independent of thesubstances which i t holds in solution or in suspension.This lawapparently holds good for solid media,for a mirror of black enamel gavethe same spectrum as a mirror of white enamel. It is not necessary toconclude that the incident rays do not penetrate into the reflectingsurface to a depth comparable with the wave-lzngtlis. These lengt,hswould be too small to produce appreciable absorption. A layer ofC. H. BGENERAL AND PHYSICAL CHEUISTRY. 139quinine acetosulphate showing Newton’s rings (yellow of the first andblue of the second order) has no absorptive effect on the solarspectrum. The same substance gives the same reflection whetherrough or polished: the polished surfnce increases the total quantityof reflected rays, but the relative intensity of different regions of thespectrum, i.e., the actznic colour of the substance, depends on thenature of the substance employed.Widening of the Lines in the Hydrogen Spectrum.By D.v. MONCKHOVEN (Compt. rend., 95, 378--38l).-The author employeda, vacuum tube in the shape of a capital H, the horizontal part beinga capillary tube 0.5 mm. in diameter, whilst tlhe vertical limbs werewider and were provided a t each end with an electrode, of which therewere consequently two pairs. Under varying degrees of pressure, andwith induction coils of different power, he found that the widening ofbhe hydrogen lines begins a t different pressures, but always at the pointwhere the silent discharge passes into a spark discharge. Under con-stant pressure, variations in temperature obtained by using differentcoils, produced no effect on the width of the hydrogzn lines.Whenthe current from a powerful coil is passed through a hydrogen tubeunder low pressure for one minute, the temperature rises considerablybut t8he lines remain narrow. If, however, the coil is connected witha Leyden jar, the gas is scarcely warmed, but the lines C and F arebroad. If the current from an induction coil connected with a Leydenjar is passed through the tube previously described, the tube beingfilled with hydrogen a t a pressure of 1-2 mm., the hydrogen linesare broad. If now a current from a powerful coil is passed throughthe tube, by means of the other pair of electrodes, the lines do notthicken, but a bright fine line is seen down the centre of each broadline; in other words two spectra are superposed.Since the use ofvacuum tubes and disruptive discharges gave no satisfactory proof asto whether the widening of the hydrogen lines is due to pressure or totemperature, the author passed an electric arc, obtained from a con-tinuous current, through pure hydrogen contained in a tube connectedwith a Sprengel pump. At atmospheric pressure the hydrogen lines,C and F, are seen on the continuous spectrum of the incandescentcarbon particles, F is considerably widened, C less so. The lines areuniformly brilliant, and have an appearance identical with that of thehydrogen lines in the sun and some stars; whereas in the vacuumtubes the widened lines decrease in brilliancy from the centre to theedges.At 0.25 m., the width of the lines C and F decrease, and a t0.09 m. they are almost narrow, H.1 is invisible, but the arc arid thelines increase Considerably in brilliancy. At 0.02 m., C and F arequite narrow and very brilliant, and Hp/ becomes visible. At 0.008 m.,H y becomes still more brilliant. By varying the distance between theelectrodes, or by altering the power of the current, the temperaturewas made to vary considerably, but the breadth of t)he lines alwaysremaoined the same. The author therefore concludes that the wideningof the lines in the spectrum of hydrogen i s d u e solely topre+sure and isnbso lutely independent oj’ teniperatzcre.C. H. B.C. H. B.1 140 ABSTRACTS O F CHEMICAL PAPERS.Spectrum of Water. By G. D. LIVEIXG and J.DEWAR (Proc.Roy. Xoc., 33, 274--276).-This paper is illustrative of a photographof the spectrum of an oxyhydrogen flame ; in no cases were lines of awave-length less than X 2200 observed.Influence of Temperature on the Spectra of Non-metals.By D. v. MONCKHOVEN (Comnpt. r e d , 95, 520-522) .-Plucker hasshown that most of the non-metals give two perfectly distinct spectra,one of which he regards as being due to a high, the other to a lowtemperature. If the H-shaped tube with four electrodes, previouslydescribed (preceding page), is filled with oxygen or some othernon-metal, and the gas is subjected t,o the simultaneous action of twocurrents, one from an induction-coil alone, the other from a coil con-nected with a Leyden jar, the high temperature spectrum and the lowtemperature spectrum are seen superposed.According to Plucker’shypothesis, the gas must therefore be at two different temperatures atthe same instant, a supposition which is inadmissible. The superposi-tion of the two spectra is not due to the fact that the contact breakersof the two coils do n o t vibrate in unison, thus producing alteriiationsof the two spectra which appear to be superposed, owing to the per-Ristence of the images, for in some tubes, especially if the tube befilled with oxygen, the light is radiated for several tenths of a secondafter the current is interrupted. The author attributes the changes inthe spectra of the non-metals to a particular siate of vibration of theirmolecules, depending directly on the nature of the electricity employed.A hydrogen vacuum tube subjected to the action of ordinary sparkspresents an appearance very different from that produced by inductionsparks.The stratification in a vacuum tube changes entirely accord-i n g as it is produced by ordinary sparks, by induction sparks, or by abattery of high tension. Further, each variation in the appearance ofan incandescent gas (ie., change of stratification, alterat,ion of thecolour of the light emitted, &c.) always corresponds with a partial,often an entire, change in the character of the spectrum, the effectbeing certainly independent of the temperature.Note by Abstractor.-The author’s supposition that the change inthe spectra of the non-metals is due to a particular form of molecularvibration, depending on the nature of the electricity employed, is sup-ported by Schuster’s observation of the peculiar spectrum of oxygenin the neighbourhood of the negative pole.V.H. V.C. H. B.C. H. 13.Circular Polarisation of Quartz. By J. L. SORET andE. SAKASIN (Compt. rend., 95, 635-638) .-In continuing theirrasearches, the authors have adopted the folloairig improved methodof determining the original plane of polarisation. Between thepolariser and the analyser is placed a first quartz plate, say I~evogyrate,of thickness E, a black band is brought into coincidence with a line inthe spectrum, and the position of the analyser noted. The first quartzbeing left in position, a second quartz is added of inverse rotation,and of a, thickness equal to 2E.The general appearance of thespectrum is not modified in the least, but there is a, rotation t o theright equal to 2Eg5 degrees, where q denotes the angle of rotation foGENERAL AND PHYSICAL CHEMISTRY. 141a thickness of 1 mm. A black band is brought into coincidence withthe same spectral line, and from the angle through tv hich it is necessaryto tarn the analyser, plus a certain multiple of 180", the value of @ isdeduced. The results obtained by this method agree with thosepreviously published. A table is given of the values of the angle ofrotation for different rays at 20°, deduced from observations on twopieces of quartz, one 30 mm., the other GO mm. thick. The observedvalues agree closely with those calculated by Boltzmann's formulareduced to its two first terms,7.1082930 + 0.1477086@ = 1 ( ~ 6 ~ % 1 ( ~ 1 ; 2 ~ 4 'k being the length in millimeters of the wave in air, and this for-mula may be used to calculate the angle of rotation of a ray of anywave-length between A and 0.For rays more refrangible than 0,the formula no longer holds good, even though three or four terms ofthe series are taken. By substituting I, the wave-length in quartz,for A, the wave-length in air, a formula is obtained, which whenreduced to two terms, approximately represents the observed rotationthroughout the entire spectrum. The agreement between the observedand calculated values is not, however, complete, and the differencesare greater than errors of observation would be.No better results areobtained by using three terms. By addition of a third term, H6,the divergence usually becomes greater.The influence of temperature on the rotation is not constant for allrays, as is generally supposed, but increases with the refrangibility.For line 24 of cadmium, the formula for correction between 0' and20' is @ = Go (1 + OW0179t). This coefficient is greater than thenumber 0*000149 obtained by several observers as the mean coefficientbetween 0" and 100" for sodium light, and is, of course, still greaterthan the coefficient for the same light between 0" and 20".C. H. B.The Metallic Galvanic Circuit of Ayrton and Perry. ByB. J. GOOSSENS (Ann. Phys. Chem. [a], 16, 551--554).-According toPerry and Ayrton (Proc.Roy. ec., 27, 219) a galvanic circuit isobtained by dipping strips of platinum and magnesium into mercury,but they were unable to obtain a similar effect with other metals.The author shows that the current obtained as above by Ayrton andPerry is a true thermo-current, caused by the evolution of heat in theformation of the magnesium amalgam (cotnpare Obach, Pogg. -4nn.,SupyL., 7, 300). T. C.By J. ELSTER and H. GERTEL (Ann. P ~ I J S .Chem. i2] , 16, 193--222).--The longitudinal polarisation of flame isonly.appare~xt, and is caused by the unequal immersion of the mire3serviiig as electrodes. I n its cross section, however, the flame appearst o be strongly polarised, the electrode in the zone of sir immediatelysurrounding the flame being always positive towards the one in theflame.The electromotive power is independent of the size of theflame. The change in the polnritly of the flame may be produced bya suitable shifting of the electrodes. The electromotive force of theElectricity of Flame142 ABSTRACTS OF CHEMICAL PAPERS.flame is dependent ofi the nature of the metals used as electrodes, andon the nature of the burning gas. It is especially great with elec-trodes of aluminium or zinc, and very weak if the electrode situatedin the surrounding zone of air is covered with a salt, such as potassiumchloride. An undoubted electrical action is obtained by the use ofwater electrodes and exclusion of metals, the electrode in the air beingpositive towards that in the flame.Flames may be comhined likegalvanic elements, and a number of them may be united so as toform a flame battery. The following theory is advanced in explanationof the above facts. Free electricity is not produced within the flameduring combustion ; but the gases from the flame, and the zone of airsurrounding the flame, have the property in contact with met& orliquids, of exciting t,he latter like an electrolyte ; and in addition tothis there is a thermoelectric excitement determined by the glow-ing condition of the electrodes. This being so, the amount andnature of the electric excitement is independent of the size of theflame, but dependent on the nature and superficial condition of theelectrodes, on the nature of the burning gases, and on the glowingcondition of the electrodes.These conclusions have been confirmedby numerous experiments.The authors conclude therefore that Hankel’s (Pogg. Ann., 81, 212)theory as to the electricity of flames is incorrect. T. c.Electrolysis of Hydrochloric Acid. By n. TomiAsI (Con@.rend., 95, 689-691) .-With platinum electrodes and concentratedacid, the positive electrode is attacked by the chlorine, and conse-quently behaves as a soluble electrode ; with dilute acid, on the otherhand, chlorine compounds are liberated a t the positive pole, but theplatinum is not attacked.Conce&ated Acid-The decomposition of 2 mols. of hydrochloricacid in solution absorbs 78.6 cals., but since the positive electrodeis attacked, the heat of formation of platinum chloride must be sub-tracted from this number.The electromotive force necessary toeffect decomposition is consequently much less than 78.6 cals. Asingle Daniel1 element is indeed sufficient to produce very slow de-composition, but a Daiiiell element (49 cals.) and a zinc-cadmiumelement (16.6 cals.) decompose the acid rapidly, with liberation ofhydrogen at the negative pole, but no liberation of gas a t the positivepole, After 20 hours, the evolution of gas continues a t the negativepole only. With two Daniel1 elements (98 cals.) decompositionis very rapid. At first there is no evolution cf gas a t the positiveelectrode, but after about a n hour bubbles of gas begin to form.After 20 hours, decomposition continues with evolution of hydrogenat the negative and oxides of chlorine a t the positive pole.Similarresults are obtained with acid of different degrees of concentration,but the limit is reached with acid of 10 per’ cent., when the amount ofplatinum dissolved is very small.Dilute Acid.-On closing the circuit, gas is evolved a t the negativepole, whilst the liquid round the positive pole becomes coloured faintlyyellow, and bleaches litmus- paper. Even after continuous passage ofthe current for 100 hours, no trace of platinum is dissolvedGENERAL AND PHYSICAL CHEMISTRY. 143Similar results were obtained with acid of different strengths down to1 per cent. The chlorine appears a t the positive pole in the form ofoxides of chlorine, wit>h probably hypoc Ldorous acid, and perhapstraces of free chlorine. Whether the oxides of chlorine are producedby the decomposition of the hydrate HCI,GH,O, or by the action of theoxygen of the water on the hydrochloric acid, cannot be ascertained.Distribution of Heat in the Ultra-red Region of the SolarSpectrum.By P. DESAIXS (Con2pt. Tend., 95, 433--436).-Theauthor has continued his measurements of the distribution of heatin that portion of the solar spectrum less refrangible than the red(Abstr., 1879, 854), using respectively flint glass and crown glassprisms with a refracting angle of 60". In the following hble d and d'indicate in minutes the angular distance of the cold band from the line D,i and i' the relative intensities of the bands. I t must not be assumed,however, that the inten4ty of the band at 15' from D with a crownglass prism is equal to that of the band at 42' from D with it flintglass prism.Crown Glass (Jd!j l l t h , 12th, 13th, 1881).i. 20.0 19.0 22 26.6 23.5 17.0 19.0d.60.5 80.5 92 117.4 127.4 147.0i. 15.0 5.5 10 - 2.5 -C. H. B.d. 15.0 18 0 24 31.0 34.5 444.5 5Q.5Flint Glass (July 17512, 19th, 1881).d'. 42 45.0 55 58.0 68.0 73 77.2 82 88 92.5 96i f . 20 18.0 1 6 23.0 26.5 24 25.0 24 16 20.0 16d'. 100 103.0 108 122.0 130.0 148 157.0 170 175 185.0i'. 25 21.5 26 16.5 20.0 6 15.5 7 2 -With prisms of flint and crown glass, the spectrum extends t o amuch greater distance beyond the extreme red than with a prism ofrock salt. With rock salt, the limit is only 80' from the extreme red,whilst with flint glass it extends as far as 1" 40'.C. H. R.Law of Thermal Constants of Substitution. By D. TOMMASI(Cornpt. Tend., 95, 453--456).-It has been stated that the author'slaw (Abstr., 1882, 12-57) does not hold good in the case of solublesalts formed by weak acids. He therefore cites a number of examplesto show that wherever the calculated number differs from that actuallyobtained, the difference is due to the dissociation which takes place onsolution, the coefl-icient of dissociation of the particular substance notbeing the same as that of the corresponding potassium salt. Theclose agreement between the calculated and actual numbers in thecase of sodium, ammonium, lithium, strontium, and calcium sulphidessllows that the coefficient of dissociation of these compounds is thesame as that of potassium sulphide.The difference between thenumbers found and calculated is considerable in the case of ammoniumcarbonate and ammonium phenate, where also the dissociation is con144 ABSTRACTS OF CHEMICAL PAPERS.siderably greater than that of the potassium compounds. For theEame reason there is a considerable difference between the twonumbers in the case of mercuric cyanide. C. H. B.Law of Cooling. By C. R ~ T I ~ R E (Compt. rend., 95, 452-453.-The radiating body was a platinum wire heated by means of anelectric current. The temperature was calculated from variations inits conductivity, and the quantity of heat lost was calculat,ed byJoule's law. Under the low pressures a t which the experiments weremade, the cooling effect due to the gas present becomes of consider-able importance.The quantity of heat carried off by the air under apressure of 0.12 mm. of mercury is given approximately in the follow-ing table :-Heat radiated ina vacuum.A 200 .................... 10 times.A 400 .................... 3 ,,A 600 .................... 1 ,,A 800 .................... 3 9 )A 1000 4 ,)-1 ....................With a, platinum thread 0.1 TTIM. diameter placed horizontally in aglass cylinder 0.17 mm. in diameter, and surrounded by air under apressure of less than 0.0001 mni. of mercury, the cylinder being cooledby a current of cold water, t,he following numbers were obtained :-Temperature of the cylinder 17.3".Excess.50"1001502002503004005006007008009001000Heat lost.38.594.8175.6284.0448.0708.016lO*O3300.06035.010160*015980.0241 10.034800.0mae (at - 1).38.494.7177-4298.7476.7738.01684.03721.08107.017552.037891.081688.0176006.0aT2 (T - 0).35.493.0177.6293%445.7638.011 64.01907.02904.04193.058C8.07788.010168-0The values in the third and fourth columns are calculated fromthe formulm of Dulong and Petit, and of Rosetti respectively, theconstants being obtained from an experiment in which the excess ofthe temperature of the wire was 136.3" above that of the surroundingspace. These results afiord further proof of the fact that the numbersgiven by Dulong and Petit's formula increase far too rapidly.C.H. B.Comparison of Mercurial Thermometers with the HydrogenThermometer. By J. M. CRAFTS (Compt. rend., 95, 836-839).QENERAL AND PHYSICAL CHEMISTRY. 145The table of corrections for mercurial thermometers, which is to befound in ordinary text-books, was compiled 30 years ago by Regnault,but that experimenter himself pointed out that owing to the greatvariation in the composition of glass, errors might arise from theapplication of his tables to all mercurial thermometers. Regnault'sinstruments have been destroyed, and the manufactory in which theywere made has ceased to exist ; moreover the composition of the glassnow used in France differs very considerably from that of the glassused by Regnault. The author has therefore undertaken a revision ofthe table.The boiling of water a t different pressures gives the meansof determining accurately temperatures between 80" and 150".Between 140" and 350" the author uses naphthalene and benzophenonea t varying pressures. He has described elsewhere the methods usedfor determining with the aid of a hydrogen thermometer the exactpressures corresponding to any given boiling points of these liquids.By tabulating these results, he obtains hhe pressure under which it isnecessary to boil either liquid to maintain for any required time aconstant temperature. By these means, he has compared 15 ther-mometers with hydrogen thermometers. Two sets of seven of thesethermometers were of flint glass, by two different French makers, andthe other of soda glass, by a German maker.A table* showing theamount of error of the mercurial thermometers for temperatures from110-330" accompanies the paper. The same table gives the com-parison of these errors with those given by Regnault. The resultshave been confirmed by experiments with twelve other thermometersof peculiar construction. E. H. R.Limit of the Liquid State. By J. B. HANNAY (Proc. Roy. Xoc.,33, 294-321) .-A continuation of the author's researches (Abstr.,1882, 268). After some remarks on the uncertainty of our knowledgeof the exact condition of a fluid immediately above and below itscritical point, the author proceeds to divide fluids into three classes-(1) l i p i d s , which exhibit surface tension, as capilla,rity or a permanentlimiting surface; ( 2 ) gases, which cannot be reduced to liquids bypressure alone ; and ( 3 ) ucrpours, which can be so reduced. A furtherdistinction of gases and vapours lies in the fact that the curve repre-senting pressure and volume of a gas is a continuous straight line,whereas a part of the curve representing pressure and volunie of avapour is asymptotic.The author proposes to show that the gaseousstate is entirely dependent on the mean velocity, and not on the freepath of the molecule. Numerous experiments were made to ascertainthe critical temperature and pressure of alcohol under its own vapour,and under that of certain gases, as hydrogen and nitrogen. which donot attack and are not dissolved by the alcohol.A modified form ofAndrews's apparatus was used. The manometers were filled with hydro-gen, as the only gas which follows Boyle's law at high pressures, andthe alcohol was carefully purified by an elaborate method.T'he mean of over 100 experiments gave a critical point for alcohol* The author has informed the editor that there is a misprint in the table in theoriginal ; the letters B and C should be transposeJ.--C. 4. G146 ABSTRACTS O F CHENICAL PAPERS.nnder its own vapour of 235.47" under a pressure of 67.07 atmo-spheres. In order to study the critical temperature of alcohol nndergreater pressures, hydrogen was introduced over the alcohol, in ordert o allow of the limiting surface of the liquid to be seen; but it wasfound that the crit,ical temperature was practically unaltered, evenunder a pressure of 178.8 atmospheres.Similar results were obtainedwhen nitrogen was substituted for hydrogen. The method of measur-ing the capillary height of a liquid under various temperatures andpressures was also tried, and it was shown that the capillary height ofa liquid is lowered by a gas under pressure impinging on its surface ;this phenomenon would follow naturally from a constant distnrbanceof the surface of the liquid, owing to the high velocity of the hydro-gen molecules striking it. Capi1larit.y is not then a true measure ofthe cohesion of a fluid, for were the pressure sufficiently high, thesurface of the liyuid might be made to disappear while its interiorwas in a truly liquid condition.Similar experiments were made with carbon bisulphide and tetra-chloride and with methyl alcohol, the same general results being ob-tained.The critical point of carbon bisulphide under its own vapour wasfound to be 277.68" at 78.14 atmospheres ; under hydrogen, 274.93" a t171.54 atmospheres ; under nitrogen, 273.12" a t 141.45 atmospheres ;this last result is probably affected by the solubility of the nitrogen inthe carbon bisulphide. The capillary action of this liquid is alsoweakened by a gas impinging upon its surface.Determinations of the critical point of methyl alcohol under itsown vapour gave the following results:--232*76" at a pressure of72.55 atmospheres ; under hydrogen 230.14" at 128.60 atmospheres ;and uuder nitrogen, 277.92" at 191.40 atmospheres, or 225.82" at262 atmospheres.With carbon tetrachloride, the results were 28251" a t57.57 atmospheres under the pressure of its own vapour, and 277.5t;Oat 142.82 atmospheres under nitrogen. It was found impossible touse hydrogen, for it attacked the tetrachloride, with formation of chlo-roform, and other compounds. I n conclusion, the author views thefour states of matter thus :-lst, the gaseous, which exists from thehighest temperature down to an isothermal passing through the criticalpoint, and depending on temperature or molecular velocity ; 2nd, thevaporous, bounded on the upper aide by the gaseous, and on the lowerby absolute zero, and dependent, upon the length of the mean free pathof the molecule; 3rd, the liquid, bounded on the upper side by thegaseous, and on the lower by the solid state; 4th, the solid.Thegaseous state is thus the only one which is not affected by pressurealone, or in which the molecular velocity is so high that the collisionscause a rebound of sufficient energy to prevent grouping. Anotherdistinction between the gaseous and vaporous states lies in the fact t'hatt>he former is capable of acting as a solvent of solids (Abstr., 1382,271). V. H. V.By W. SPRING (Bey., 15,1940--1945).-Between 0" and 100" the expansions of ammonium andrubidium sulphates are sensibly equal, potassium chromate onlyexpands at a slightly greater rate, but in the case of potassium sulphateExpansion of Isomorphous SaltsGENERAL AND PHYSICAL CHEMISTRY.147the expansion is about 10 per cent. greater. The discrepancy isexplained by the fact that a given volume of potassium sulphnte con-tains a larger number of molecules than the other salts, for on dividingthe sp. gr. by the molecular weight of each salt there is obtained :K,S04 : *015316; Am2S04 : *013664 ; Rb,S04:*013657 ; K2Cr04 : .01412.Taking the ratio of the molecules of K2S0, to Am2SO4, there isobtained 0.015316 + 0.013664 = 1.21, whilst the ratio of the expan-sions of the same two salts is about the same figure, 0.012645 +0.011191 = 1.29. E’rorn these results, i t is probable that the expan-sions of the alums are not absolutely the same, although the differencesfall within the limits of error (cf.Spring, Abstr., 1882, 1020 ; Petter-son, Abstr., 1882, 1259).Modification of the Usual Statement of the Law of Iso-morphism. By D. KLEIN (Conzpt. rend., 95, 781--784).-Mitscher-lich stated the law of isomorphism as follows:-1. Two bodies arecalled iPomorphous when, having the same crystalline form, they cancrystallise together in the same crystal. 2. Isomorphous bodies havean analogous chemical composition. The author girea in the order oftheir discovery certain exceptions to the second part of this law. Hegoes ou to state that in previous communications he has describeda t uiigstoboric acid, 9WOJ,B203,2H20 + 22Aq, isornorphoics withlSlarignac’s octohedral silicotungstic acid, 12W0,,Si02,4H20 + 29Aq ;also a monosodium tungstoborate, 9\VO:{, B,O,,Na,O + 23 Aq, iso-n ~ o r p k o ~ s with the acids just mentioned ; and further a diammoniumtungstoborate, 9W0,,B,0,,2NK40 + 19Aq, isomorphous with anammonium metatungstate described by Marignac, and a dibariiimtungstoborate, 9W03,BL03,2Ba0 + 18Aq, isomorphous with the cor-responding metatungstate, The author states that the tungstoboricacid employed by him contained only a trace of silica, and that hisanalyses have in this respect been confirmed by Mnrignac.In con-sequence of these facts, a modification of Mitscherlich’s law has becomenecessary, and the author therefore gives the following, already pro-posed by Marignac, as a substitute tor the second part of the law inquestion :-Isomory?~ozcs bodies haue eitlier a siinilay clfemical cornposition,or possess only a slightly diferent perceutage comnposition, avid a1 1 coutaineither a common group of eleinerhts or groups of elements qf iclenticulcliertiicw fuILctiows, which form by far the gyeater part of’ their weight.Observations on Crystallisation.By G. BR~~GELXANN ( B e r . , 15,1833--1839).-After giving a short account of the deveiopment of thetheories of isomorphism, dimorphism, &c., with special reference totheir bearing on chemical composition, the author proceeds to show a tsome length that crystallisation of two sulnstauces in the same form ortlie same crystal does not always depend on any relation in theirchemical composition, a fact which has already beell pointed out inseveral instances, notably by G.Rose, in the case of sodium nitrateand calcspar. The examples brought forward by tbeauthor are coppersulphate and potassium dichromate, copper sulphate and cobalt chlo-ride, borax and potassium chlorate ; in most cases the cold saturatedsolutions were mixed in varying proportions, but in some crystals of theA. J . (3.R. H. R148 ABSTRACTS O F CHEMICAL PAPERS.one substance were introduced into saturated solutions of the other.In all cases coloured solutions were used, and perfect co-crystallisationwas observed, the colours being different, in various parts of the samecrystal. Compounds therefore of the most dissimilar atomic constitu-tion can crystallise together, their power of so doine; being a functionof the physical conditions in which they are found, and not of theirchemical composition.The occurrence therefore of a body in a definitecrystalline form is no criterion of its individuality, and the conceptionof isomorphism possesses only a nominal significance, as it cannot beused as a separate means of classificat,ion, but only in confirmation offacts otherwise obtained. J. I(. C.Experiments in Crystallisstion Exemplifying Berthollet’sLaw of Affinity. By G. BXUGELMANN (Bey., 15, 1840--1841).-Thefollowing experiments are of interest as touching Berthollet’s law, thata liquid in which two salts have been dissolved contains the acids andbases of each reciprocally combined. Equal volumes of cold saturatedsolutions of cobalt chloride and nickel sulphate were mixed and allowedto evaporate spontaneously ; the crystals obtained consisted of bothmetals in the forrn of sulphates, and the chlorides of the two metalswere left in solution.Similar results mere obtained with copper sul-phste and cobalt chloride, as well as with copper sulphate and potas-sium dichromate ; in the former case, the first crop of crystals containedboth metals as sulphates, together with small quantities of chlorides ;in the latter, crystals of the mixed sulphates of copper and potassiumwere first deposited, then various mixtures of tlie chromates andsulphates, and finally a mixture of chromates of tlie two metals. Inevery case the crystallisation seems to have proceeded in a liquid con-taining four different salts.Nature of the Vibratory Movements which accompany thePropagation of Flame in Mixtures of Combustible Gases.Abstr., 1881, 971).-The authors employed a tube 3 meters long and0 03 meter in diameter.The combustible gas was a mixture of nitricoxide and vapour of carbon bisulphjde. An image of the tube wasthrown on to a, cylinder covered with sensitive paper and rotatingwith a known velocity. The photographs show that the flame travelsat first with a uniform velocity, but afterwards performs a series ofvery rapid osciilations, the regularity, duration, and amplitude ofwhich vary a t different parts of the tube. Uniform motion cothinixeswith a velocity of 1.10 meter per second to a distance of 0.75 meterfrom the mouth of the tube. Beyond this point the flame, and con-sequently the mass of gas, is thrown into vibration, the vibrationsbeing both simple and compound. The points a t which the vibrationis simple are generally spaces of one or two-fifteenths the length ofthe tube. The duration of successive vibrations varies between 0.025and 0.0034 of a second. The durations are in the simple ratios of1, 2, 3, 4, 5, 6, but no relations could be traced between these timesand the position of the flame in the tube. As a matter of fact, thevibrating mass of gas is composed of two distinct columns, one ofburnt gas, the other of cold gas, the lengths and densities of whichJ. K. C.By AlALLARD and LE CHaTELIER (Co???pt. rend., 95, 599-560 ; see alsINORGANIC CHEMISTRY. 149vary a t every instant. The amplitude appears to be greatest forvibrations of long period, and is particularly great in the last third ofthe tube, a t the poiiit where one of the vibrating segments is situatedwhen the tube gives the first harmonic from its fundamental note.The amplitude a t this point is as high as 1-10 meter. Since theoscillations of the flame are simply those of layers of burning gas,these experiments gave the first precise idea of the amplitude of thevibrations of a mass of gas emitting a sound. These vibratory move-ments necessarily correspond with high pressures. From calculationsbssed on the variation in volunie, measured by the oscillation of theflame, it is found that the mean pressure is a t Ieast five atmospheres,and for mixtures in which the initial velocity is greater than 1 meter,the pressures will be considerably higher. The mean velocity of pro-pagation appears to increase with the amplitude and rapidity of thevibrations. I n one experiment, the limits were 1.10 meter and5.40 meters, in anotber, 0.97 meter and 8.60 meters. I n anotherexperiment, the explosive wave was formed a t a distance of two-thirdsthe length of the tube from the mouth, Le., a t the point where theamplitude of vibration was greatest, and the last third of the tube wascompletely shattered. The brilliancy of the flame varies a t successivephases of the same vibration, being greater when the flame movesforward than when it moves backward ; these differences increase wit'hthe amplitude of vibration, and are undoubtedly connected withvariations in pressure.With a tube 0.01 meter in diameter, the flame is extinguished a t adistance of about 1.5 meter from the mouth. The vibratory move..ment is produced at a distance of 0.18 meter from the mouth of thetube, instead of at 0.75 meter. and tthe amplitude of vibration increasesmore rapidly. The mean velocity of propagation is at first very small,but attains a rate of 4.50 meters per second a t a distance of 0.5 meter,and becomes almost nothing just. before the extinction of the flame.The narrowing of the tube favours the development of the vibratorymotion with all its consequences, C. H. B