102 General a n d P h y s i c a l C h e m i s t r y . Influence ofTemperature and Pressure on the Spectra of Gases. By (3. CIAhircIm (Chem. CeTLtr., 1878, 689).-The spectra of chlorine, bromine, and iodine in the gaseous state show consider- able differences. Diluted bromine vapour gives a spectrum an alo- gons to that of chlorine ; when examined under pressure, the bromine spectrum approaches that of iodine. The spectrum of iodine vapour under considerable pressure is not comparable with that of any of the other halogens under any circumstances ; so also dilute chlorine yields a spectrum presenting little analogy to those of bromine and iodine, whilst the spectrum of compressed chlorine is closely analogous to that of diluted bromine or iodine. The spectra of those elements, which exhibit great chemical activity (H: Na, 0, C1, Br, I), are markedly altered by increase of pressure.M. M. P. M. Spectroscopic Investigation of the Constitution of Liquids. By H. BGRGER (Deut. Chenz. Ges. Ber., 11, 1876--1878).-The author describes an apparatus he has constructed for the investigation of the questions-(1.) Are the absorption-bands of mutually indifferent liquids affected by mixture? (2.) Is the absorption-spectrum of a liquid aBected by its temperature? He is engaged in investigating solutions of Co, Cu, and Na salts. C. F. C. Absorption-Spectra. By J. LANDAUER (Deut. Chem. Ges. Ber., 11, 17'72--1775.-On the addition of a concentrated acid to a safranine salt, the red colour of its solution changes to violet, indigo-blue, and finally to emerald-green. The change of colour takes place in the iseverse order, when water is added to the acid solution of safranine.The solution gives a characteristic spectrum for each colour. In a compound of picric acid with safranine or with rosaniline, picric acid can no longer be detected by means of the spectroscope. From these facts, the author concludes that absorption-spectra c m provide a clue to the composition of a compound only when the colour of the substance is characteristic of its chemical composition. w. c. w. Plant& Secondary Battery. By R. BOTTOER (Cllem.. Cent,.., 1878, 574) .-According to Plant&, if two spirals of thin sheet lead immersed in dilute sulphuric acid are connected wit,h the wires from a battery, the anode spiral becomes covered with lead peroxide, and the cathode with a grey compact film.If' the battery be disconnected when oxygen begins to be evolved a t the anode, the lead spirals are said to act as a powerful battery, and to retain their electromotive force for some days. The author finds, however, that the electromotive force diminishes rapidly, and that after 24 hours no further action is obtainable from such an arrangement,. M. M. P. M. VOL. XXXVI. i102 ABSTRACTS Ok’ CHEMICAL PAPERS. Production of Rotatory Movements in Mercury. By R. BOTTGER (Chem. Cedi-., 1878, 560).-If a drop of pure merciiry, 3 or 4 mm. in diameter, placed on a watch-glass, and covered with a dilute solution of mercuric nitrate, be touched with a rod of zinc about the size of a needle, a peculiar palpitating movement of the drop hecomes visible ; if a second rod of zinc be now brought into contact with the mercury, the drop rotates rapidly ; after a time the motion ceases. The action is no doubt caused by electric currents.M. M. P. M. Production of a High Temperature by means of Ammonium Nitrate. By R. BOTTGER (Chern. Cmtr., 1878, 560).--If ammonium nitrate be dissolved in water, the temperature falls cnnsiderably, but if zinc-dust equal in amount to the ammonium nitrate used be now thiwwn into the liquid, the temperature suddenly rises, and the liquid boils violently ; if the experiment is performed in a beaker or a flask, the vessel is generally shattered. Material for Standard Weights and Measures. By F. MOHR (Ann. Chew., 194, 40-53) .-On looking over tables of co-effi- cients of expansions, i t is found that for lo, platinum expands 9-millionths of its length; iron, 11 ; glass, 9 ; Carraramarhle, 8 ; black marble, 4$.The last-named material, the uncrystallised blwk marble, has been already used with success forthe stems of pendulums. It i s recommended now that this substance be used for constructing an unalterable standard measure. The material is to be had suitable for any dimensions, is easy to work, takes a beautiful polish, and is soft enough to yield readily to the diamond for the graduation of an enti1.e meter. For weights, rock crystal is recommended. I t is of importance thRt all weights should be made of a material of the same density, so that displacement and alteration through atmospheric conditions shall be the same in every piece. It is also important that the specific gravity of the pieces shall approximate as closely as possible to that possessed by most of the bodies separated out in analysis, and again that they hare a considerable degree of hardness to protect them against wear and tear.Instead of rock crystal, the author proposes massive glass containing a large proportion of silica. For the smaller weights lie recommends aluminium (specific gravity = 2-56), instead of platinum, or perhaps a somewhat heavier and more durable alloy with silver. All pieces to he round, and to be taken hold of in the middle, not at the edges. Except in gasometric operations, i t has so far never been thought necessary to take into account the conditions indicated by thermometer and barometer on weighing.* The influence and effect of different elevations above the sea level, with weights some of brass and some of platinum in the same set, is not noticed.A kilogram weight of rock crystal on one day, by a barometric fall of 10 mm. on the next may be reduced by 3.3 mgms. Why, then, adjust a standard kilogram to the decimal of a milligram, if atmospheric *i Abstractor’s Note.-At any rate an exception to this assertion may be men- tioned in the case of Crookes’s determination of the atomic weight of thallium, where the influence of bnrometic pressure was taken into account. M. M. P. M.INORGANIC CHEMISTRY. PO3 changes indicated by barometer and thermomeber can produce such an effect ? I n the original derivation of the kilogram, three pmctical errors were made : (1.) That water of 4" was chosen as object of com- parison.Water of any other temperature has just as definite a volume at that temperature as a t 4O, and the latter is not to be had in the greatest part of the year, and not only the water, but also balance and weight, and the whole surroundings generally, mush possess the same temperature, if a weighing lasting some considerable time is to be of value. On the contrary, i t i s easy to keep to a. mean temperature of 17.3" for any lengt,hof time. (2.) 'Yhat the weighing should have been made in ziacuo. That this could not have been correctly done arises from the facts that the weight of a litre of dry air of normal constants was not known, and finally, because the third error was com- mitted.(3.) That the specific gravity of the platinum employed had not been estimated. It is unknown if t,he temperature of the air and objects and barometric pressure were noted in the comparison. With regard to the new standard measure, i t is in t,he highest degree in- different what fraction of the earth's circumferenee it makes. w. s.102General a n d P h y s i c a l C h e m i s t r y .Influence ofTemperature and Pressure on the Spectra ofGases. By (3. CIAhircIm (Chem. CeTLtr., 1878, 689).-The spectra ofchlorine, bromine, and iodine in the gaseous state show consider-able differences. Diluted bromine vapour gives a spectrum an alo-gons to that of chlorine ; when examined under pressure, the brominespectrum approaches that of iodine.The spectrum of iodine vapourunder considerable pressure is not comparable with that of any ofthe other halogens under any circumstances ; so also dilute chlorineyields a spectrum presenting little analogy to those of bromine andiodine, whilst the spectrum of compressed chlorine is closely analogousto that of diluted bromine or iodine.The spectra of those elements, which exhibit great chemical activity(H: Na, 0, C1, Br, I), are markedly altered by increase of pressure.M. M. P. M.Spectroscopic Investigation of the Constitution of Liquids.By H. BGRGER (Deut. Chenz. Ges. Ber., 11, 1876--1878).-The authordescribes an apparatus he has constructed for the investigation of thequestions-(1.) Are the absorption-bands of mutually indifferentliquids affected by mixture? (2.) Is the absorption-spectrum of aliquid aBected by its temperature? He is engaged in investigatingsolutions of Co, Cu, and Na salts.C. F. C.Absorption-Spectra. By J. LANDAUER (Deut. Chem. Ges. Ber., 11,17'72--1775.-On the addition of a concentrated acid to a safraninesalt, the red colour of its solution changes to violet, indigo-blue, andfinally to emerald-green. The change of colour takes place in the iseverseorder, when water is added to the acid solution of safranine. Thesolution gives a characteristic spectrum for each colour.In a compound of picric acid with safranine or with rosaniline,picric acid can no longer be detected by means of the spectroscope.From these facts, the author concludes that absorption-spectra c mprovide a clue to the composition of a compound only when the colourof the substance is characteristic of its chemical composition.w. c. w.Plant& Secondary Battery. By R. BOTTOER (Cllem.. Cent,.., 1878,574) .-According to Plant&, if two spirals of thin sheet lead immersedin dilute sulphuric acid are connected wit,h the wires from a battery, theanode spiral becomes covered with lead peroxide, and the cathodewith a grey compact film. If' the battery be disconnected whenoxygen begins to be evolved a t the anode, the lead spirals are said toact as a powerful battery, and to retain their electromotive force forsome days. The author finds, however, that the electromotive forcediminishes rapidly, and that after 24 hours no further action isobtainable from such an arrangement,.M. M. P. M.VOL. XXXVI. 102 ABSTRACTS Ok’ CHEMICAL PAPERS.Production of Rotatory Movements in Mercury. By R.BOTTGER (Chem. Cedi-., 1878, 560).-If a drop of pure merciiry, 3 or4 mm. in diameter, placed on a watch-glass, and covered with a dilutesolution of mercuric nitrate, be touched with a rod of zinc aboutthe size of a needle, a peculiar palpitating movement of the drophecomes visible ; if a second rod of zinc be now brought into contactwith the mercury, the drop rotates rapidly ; after a time the motionceases. The action is no doubt caused by electric currents.M. M. P. M.Production of a High Temperature by means of AmmoniumNitrate. By R. BOTTGER (Chern. Cmtr., 1878, 560).--If ammoniumnitrate be dissolved in water, the temperature falls cnnsiderably, butif zinc-dust equal in amount to the ammonium nitrate used be nowthiwwn into the liquid, the temperature suddenly rises, and the liquidboils violently ; if the experiment is performed in a beaker or a flask,the vessel is generally shattered.Material for Standard Weights and Measures.By F. MOHR(Ann. Chew., 194, 40-53) .-On looking over tables of co-effi-cients of expansions, i t is found that for lo, platinum expands9-millionths of its length; iron, 11 ; glass, 9 ; Carraramarhle, 8 ; blackmarble, 4$. The last-named material, the uncrystallised blwk marble,has been already used with success forthe stems of pendulums. It i srecommended now that this substance be used for constructing anunalterable standard measure.The material is to be had suitable forany dimensions, is easy to work, takes a beautiful polish, and is softenough to yield readily to the diamond for the graduation of an enti1.emeter. For weights, rock crystal is recommended. I t is of importancethRt all weights should be made of a material of the same density, sothat displacement and alteration through atmospheric conditions shallbe the same in every piece. It is also important that the specificgravity of the pieces shall approximate as closely as possible to thatpossessed by most of the bodies separated out in analysis, and againthat they hare a considerable degree of hardness to protect them againstwear and tear. Instead of rock crystal, the author proposes massiveglass containing a large proportion of silica.For the smaller weightslie recommends aluminium (specific gravity = 2-56), instead ofplatinum, or perhaps a somewhat heavier and more durable alloy withsilver. All pieces to he round, and to be taken hold of in the middle,not at the edges. Except in gasometric operations, i t has so far neverbeen thought necessary to take into account the conditions indicatedby thermometer and barometer on weighing.* The influence andeffect of different elevations above the sea level, with weights someof brass and some of platinum in the same set, is not noticed. Akilogram weight of rock crystal on one day, by a barometric fall of10 mm. on the next may be reduced by 3.3 mgms. Why, then,adjust a standard kilogram to the decimal of a milligram, if atmospheric*i Abstractor’s Note.-At any rate an exception to this assertion may be men-tioned in the case of Crookes’s determination of the atomic weight of thallium,where the influence of bnrometic pressure was taken into account.M.M. P. MINORGANIC CHEMISTRY. PO3changes indicated by barometer and thermomeber can produce such aneffect ? I n the original derivation of the kilogram, three pmcticalerrors were made : (1.) That water of 4" was chosen as object of com-parison. Water of any other temperature has just as definite avolume at that temperature as a t 4O, and the latter is not to be had inthe greatest part of the year, and not only the water, but also balanceand weight, and the whole surroundings generally, mush possess thesame temperature, if a weighing lasting some considerable time is tobe of value. On the contrary, i t i s easy to keep to a. mean temperatureof 17.3" for any lengt,hof time. (2.) 'Yhat the weighing should havebeen made in ziacuo. That this could not have been correctly donearises from the facts that the weight of a litre of dry air of normalconstants was not known, and finally, because the third error was com-mitted. (3.) That the specific gravity of the platinum employed hadnot been estimated. It is unknown if t,he temperature of the air andobjects and barometric pressure were noted in the comparison. Withregard to the new standard measure, i t is in t,he highest degree in-different what fraction of the earth's circumferenee it makes. w. s