This method was tested in the following manner :Either a weighed quantity of solid or (where the weight is given in brackets) a measured volume of standard solution of malonic acid was added to approximately 2N-sulphuric acid, excess of permanganate solution added, and the whole heated to 80-90° for ten minutes (or longer with the more dilute solutions); the solution was then rendered alkaline with strong aqueous potassium or sodium hydroxide, and the heating continued for some minutes; finally, excess of sulphuric acid was added, then for convenience excess of oxalic acid, and this excess determined with more permanganate. The results are given below: The figures show that the explanation given is the correct one. At the same time they indicate the limits of dilution (calculated on the concentration at the commencement of the reaction) within which the method can be employed quantitatively. In the first experiment some decomposition of the malonate through heat has already taken place, whilst in the last two the results are uncertain. Further experiments on similar lines have indicated that to obtain accurate results it is essential to work below 90° (the reaction commences at about 70°, and proceeds rapidly between 80° and 85°) and to avoid great excess of sulphuric acid. Mestrezat (Ann. Chim. Anal., 1907, xii., 173) states that tartaric and malic acids react with potassium permanganate in the same manner, with the production of formic acid and carbon dioxide. He suggests a similar method for their estimation. The case of citric acid (Wöhlk, Zeit. Anal. Chem., 1902, xli., 77) is more complex, but the reaction proceeds on corresponding lines, the chief products being acetone and carbon dioxide. 1 It is evident that the permanganate reacts with all this series of acids in a parallel manner, and can therefore be used to estimate any one of them only in the proved absence of the others. (To be continued). ROYAL SOCIETY. Ordinary Meeting, June 16th, 1910. Sir ARCHIBALD GEIKIE, K.C.B., President, in the Chair. PAPERS were read as follows: "Experimental Researches on Vegetable Assimilation and Respiration. VI. Some Experiments on Assimilation in the Open Air." By D. THODAY. In these experiments Sachs's half-leaf dry-weight method has been employed, with modifications suggested in a previous paper for avoiding errors due to shrinkage of the insolated half-leaves. Turgid leaves of Helianthus annuus were found in bright sunlight to increase in dry weight 17 mgrms. per hour per sq. decim.; thus Sachs's high value is confirmed. Even a slight loss of turgor, however, was accompanied by a diminution in the rate of increase. For this high rate of assimilation a leaf-temperature of 23-24° C. is probably required. It is suggested that Brown and Escombe's low results in bright diffuse light indicate that the stomata of Helianthus leaves open to their full extent only in light which is similar in quality to sunlight and approaches it in intensity. Detached leaves of Catalpa bignonioides when fully turgid increased 5 to 6 mgrms. per hour per sq. decim. in bright sunlight; in this plant stomata occur only on the underside of the leaf. The effect of detachment from the plant upon the rate of assimilation is considered, and evidence is adduced in support of Sachs's assumption in the case of H. annuus, that concurrently with assimilation part of the products of photosynthesis are translocated from leaves still attached to the plant. "A Case of Sleeping Sickness Studied by Precise Enumerative Methods; Regular Periodical Increase of the Parasites Disclosed." By Prof. RONALD Ross, F.R.S., and DAVID THOMSON, M.B., B.Ch. The enumerative methods referred to consist of modes of detecting blood parasites when very scanty, and of counting them accurately. The methods have been applied to a case of sleeping sickness in the clinic of Prof. Ross in Liverpool for seventy-three days continuously, and have shown that the numbers of T. gambiense in this patients' blood undergo remarkable periodical variations about every seven to eight days. The authors state that, so far as they can ascertain, though the numbers of trypanosomes had been known previously to vary from time to time, the regular periodicity revealed in their case appears to have been overlooked, possibly owing to insufficient methods of counting. The authors report that numerous parallel researches are being conducted, and give a chart. "Recognition of the Individual by Hamolytic Methods." (Preliminary Communication). By Dr. CHARLES TODD and R. G. WHITE, M.B. "Receptors and Afferents of the Third, Fourth, and Sixth Cranial Nerves." By FRANCES M. TOZER, B.Sc., and C. S. SHERRINGTON, F.R.S. (Physiology Laboratory, University of Liverpool). (a) "Trypanosome Diseases of Domestic Animals in Uganda." By Colonel Sir DAVID BRUCE, C.B., F.R.S., Army Medical Service; Captains A. E. HAMERTON, D.S.O., and H. R. BATEMAN, Royal Army Medical Corps; and Captain F. P. MACKIE, Indian Medical Service. (Sleeping Sickness Commission of the Royal Society, 1908-09). The commonest trypanosome disease among cattle Uganda is caused by a trypanosome of the dimorphon | investigated. Their advantages and limitations were caretype, which is probably similar to that sent from the West Coast by Dutton and Todd under the name of T. dimorphon, and described by Laveran and Mesnil, and Thomas and Breinl. It seems now that probably Dutton and Todd's T. dimorphon is quite different from that which they sent to Liverpool under that name. The original strain of T. dimorphon described by them had well-marked di-morphic characters, whereas the trypanosome sent to Liverpool was mono-morphic. There is some evidence forthcoming that the T. dimorphon, as described by Dutton and Todd, really exists, and has been described as occurring in North-West Rhodesia by Montgomery and Kinghorn, and also on the West Coast. Under these circumstances it seems better to give the mono-morphic form, which has up to the present been known by the name of T. dimorphon, a new name. It is a small trypanosome, short and stout in form; averaging 13.2 microns in length, with a maximum of 160 and a minimum of 10.6. It has no free flagellum, and is restricted in its movements. The conclusions are that : 1. There is an important trypanosome disease of domestic animals in Uganda. 2. The trypanosome is similar in morphology, action on animals, and cultural characters to T. dimorphon as described by Laveran and Mesnil, and to Dr. Edington's trypanosome from Zanzibar, except that this trypanosome is not pathogenic to guinea-pigs. 3. The carrier is unknown, but is probably a Tabanus, possibly a Glossina, and improbably a Stomoxys. (b) "Experiments to Ascertain if Cattle may act as a Reservoir of the Virus of Sleeping Sickness (Trypanosoma gambiense). "The Lignite of Bovey Tracey." BY CLEMENT REID, F.R.S., and ELEANOR M. REID, B.Sc. IN this outline of the conclusions reached by the International Commission formed in 1900 to investigate the question of an international auxiliary language, different members of the Commission have explained the need for a common language, the principles which must be adopted in its construction, and its relationship to science. The many objections to the idea which have been raised on all sides are skilfully met at the beginning of the book, and if the main contentions of the first chapter are once generally accepted a definite step towards the adoption of the universal language may be the outcome. The members of the Commission have found that Esperanto has much to recommend it, though it is defective in some respects and cumbersome in use, and the language they suggest is based on the same principles and has a certain amount in common with it. The outlines of the grammar of the new language "Ido" are shortly explained, and a very striking tribute to its value is to be found in the appendix, in which a short Fassage has been translated from English into Ido, and then re-translated by a writer who was unfamiliar with the original; the translated version shows a high degree of accuracy. Anyone who is interested in the establishment of a universal auxiliary language should certainly study this book. Platinum Resistance Thermometry at High Temperatures. By C. W. WAIDNER and G. K. BURGESS. Washington: Government Printing Office. 1910. THIS reprint from the "Bulletin of the Bureau of Standards," vol. vi., No. 2, gives an account of a research in which the use of platinum resistance thermometers was thoroughly fully studied, and the most satisfactory methods of construction and using them were tested. The different types of resistance thermometers are described in the text, and details are given of the calibration of them by observing the resistance in melting ice, steam, and boiling sulphur. Methods of determining melting- and freezing-points of several metals are described, and a summary of the general conclusions to be drawn from the investigation is added. These conclusions relate to the scales employed, to the behaviour of the thermometers in different circumstances, &c., and incidentally some notes on the boiling-point of sulphur are included. ABC Five-figure Logarithms and Tables for Chemists. By C. J. WOODWARD, B.Sc. London: E. and F. N. Spon, Ltd.; Simpkin, Marshall, Hamilton, Kent, and Co., Ltd. New York: Spon and Chamberlain. Birmingham Cornish Brothers. 1910. THIS Small book of tables will be appreciated by chemists, for it is exceedingly compact, and yet contains most of the data which are to be found in much larger and more pretentious works. Five-figure logarithms are given, with explanations of the methods of using them, and examples of such calculations as the reduction of gas volumes to S.T.P. are worked out. Conversion tables are also included, as well as tables of analytical factors. Die Gewinnung des Broms in der Kaliindustrie. ("The Production of Bromine in the Potash Industry"). By Dr. phil. MAX MITREITER. Halle-a.-S. Wilhelm Knapp. 1910. THE growing importance of bromine as a by-product in the potash industry certainly warrants the appearance of this monograph, for information regarding the methods employed, &c., is, generally speaking, difficult to procure, and hitherto has had to be collected from scattered sources. The monograph deals first with chemical methods of preparation, and describes with illustrations the various forms of apparatus which have been employed for the purpose, with their most recent improvements. Electrical methods are next fully treated, and even those processes which have not proved a success commercially are described in detail, their defects and the probable reasons for their failure and the properties of bromine are also well treated, and being pointed out. Methods of purification and analysis the monograph gives a clear summary of the present state of the industry. Berichte der Deutschen Chemischen Gesellschaft. Relations between Constitution and Heat of Combustion of Unsaturated Hydrocarbons.-K. Auwers and W. A. Roth.-Hydrocarbons with conjugated double bonds usually have lower heats of combustion than their nonconjugated isomers, and thus represent structures of less chemical energy or greater saturation. Any factor which has a disturbing influence on a conjugated double bond, as shown by its spectro-chemical behaviour, also affects its thermo chemical behaviour. Thus the addition of sidechains to the carbon atom of a conjugated system usually raises the heat of combustion of the hydrocarbon; i.e., lowers its degree of saturation. These conclusions have been reached by the study of styrols and terpenes. Vol. xliii., No. 7, 1910. Thallo-acetylacetonate.-Edward Kurowski.-Thallo- | treated with 30 per cent hydrogen peroxide and the mixacetylacetonate separates in small white crystals from an ture is cooled, some perphosphoric acid, H4P208, is formed. alcoholic solution of acetyl acetone when it is boiled with Persulphuric acid anhydride, S207, can be obtained by the thallous carbonate. The crystals are quite opaque in trans- action of ozone on sulphur trioxide. mitted light, and in polarised light show strong interferencecoloration. They melt at 160°, undergoing decomposition. The same compound can also be prepared by the action of acetyl acetone on metallic thallium, but this method is not so convenient as the above, because the acetyl acetone is readily decomposed. Carbon disulphide gives a voluminous orange precipitate with an alcoholic or benzene solution of acetone acetate of thalium, and even if traces of carbon disulphide are present in the solution the liquid becomes yellow and turbid. Perchloric Acid as a Reagent in Organic Chemistry.-K. A. Hofmann, August Metzler, and Kurt Höbold. -Concentrated perchloric acid is a valuable reagent in the study of the basic properties of carbon and oxygen. It may be used to separate carbinols, ketones, and amides from resinous substances, 70 per cent perchloric acid | - M. Lead Peroxide in Elementary Analysis. Dennstedt and F. Hassler.-Although lead peroxide does absorb small amounts of carbon dioxide no appreciable error is introduced into the results of an elementary analysis by its use, provided that large amounts of carbon dioxide are not present and that not more than 10 grms. of the peroxide is employed. It is essential, moreover, to heat least half-an-hour before use. the peroxide in the combustion tube to 250-300° for at Isomeric Platinum Compounds of Organic Sulphides.-L. Tschugaeff and W. Subbotin.-The compounds of platinum chloride with organic sulphides PtCl22 2R2S exist in three forms the a - chloride, giving pure perchlorates with solutions in ether, benzene, R2S: Pt<RS.Cl; the 3-chloride, Pt<RS.C &c. The acid can be split off from the perchlorates merely by the addition of water in the case of weak bases, lime or potassium carbonate being used for strongly basic sub. stances. The authors have prepared and investigated the properties of gallein and cœrulignon perchlorates. Action of Organo-magnesium Compounds on Boron Trichloride, Sulphur Chloride, and the Chloride and Esters of Sulphurous Acid.-W. Strecker.-When boron trichloride acts on phenyl magnesium bromide only one chlorine atom is replaced by the phenyl residue, and on treatment with water phenyl boric acid is isolated. Phenyl magnesium bromide reacts with sulphur chloride to give phenyl disulphide, (C6H5)2S2, diphenyl being formed as a byproduct. With thionyl chloride the corresponding sulphoxide is formed. Symmetrical ethyl sulphite reacts as follows:SO(OC2H5)2 + 2MgBrC6H5 = 2C2H5OMgBr + SO(C6H5)2, while its isomer gives phenyl ethyl sulphone, C6H5.SO2.C2H5. Triphenylmethyl, Triphenylacetaldehyde, and Triphenylacetanhydride. Julius Schmidlin. Triphenylacetic acid chloride dissolves in a solution of phenyl magnesium iodide, carbon monoxide being given off. 2(C6H5)3C.CO.Cl+2C6H5. MgI = R2S.C and the y-chloride. The authors have now shown that the y-salt is an analogue of Magnus's salt, and thus platinum compounds with two complex ions exist. Monomeric compounds of the same composition appear to exist only in special cases. Quantitative Volatilisation of Arsenic.-P. Jarnasch and T. Seidel.-Arsenic can be quantitatively volatilised from solutions containing hydrazine sulphate if some potassium bromide or hydrobromic acid is added, the distillation taking an hour at the most. The arsenic can be determined in the distillate either as trisulphide, or as magnesium pyroarsenate, or titrimetrically. The results obtained by this method of separating arsenic from antimony, copper, mercury, and other metals are very accurate, the apparatus required is simple, and the process is rapid. Phosphorus Pentasulphide. - Alfred Stock. — The author prepared phosphorus pentasulphide by heating red phosphorus with sulphur in the proportions corresponding to the formula P2S5. The melting-point of the pure sulphide is 286-288-290°; the different results obtained being due to the fact that, like the other sulphides, it is partly decomposed when heated. Even at the ordinary = 2(C6H5)3C+2CO+C6H5.C6H5+2MgICI. have been kept for some time must be re-crystallised before temperature decomposition occurs, and preparations which Thus the reaction with a magnesium organic compound is similar to that with a metal : (C6H5)3C.CO.Cl+Ag = (C6H5)3C + CO+AgCl. The analogous bromide does not behave in the same way, but yields B-benzpinacoline and no carbon monoxide :(C6H5)3C.CO.Cl + C6H5. MgBr = = (C6H5)3C.CO.C6H5 + MgBrCl. A similar difference in the behaviour of the magnesium organic bromide and iodide has been observed with triphenylchlormethane and B-benzpinacoline. Triphenylacetaldehyde can be prepared from triphenylmethyl magnesium chloride and formic acid ethyl ester. Triphenyl acetanhydride when heated to its melting-point gives off carbon monoxide. Phospho-monoperacid and Perphosphorie Acid.Julius Schmidlin and Paul Massini.-By the action of 30 per cent hydrogen peroxide (perhydrol) on phosphorus pentoxide phosphomonoperacid is formed. P2O5+2H2O2 + H2O=2H3PO5. It is a derivative of orthophosphoric acid of formula:— HO- H-0-0 The acid is more stable in acid than in neutral or alkaline solution. It is a very sensitive reagent for manganese, with traces of which it gives a deep violet coloration when heat is applied. When commercial pyrophosphoric acid is use. Beryllium Formate.-S. Tanatar.- When beryllium carbonate is dissolved in formic acid the normal formate is obtained. It is insoluble in organic solvents. It is more or less hydrolysed by boiling in aqueous solution and is partially decomposed when heated under diminished pressure, a basic salt, Be4O(CHO2)6, subliming. The same basic salt is obtained by boiling an aqueous solution of the normal formate with the calculated amount of beryllium carbonate. MEETINGS FOR THE WEEK. FRIDAY, 8th.-Physical, 5. "Thermo-electric Balance for the Absolute Measurement of Radiation," by H. L. Callendar. Convection of Heat from a Body Cooled by a Stream of Fluid," by A. Russell. "On Hysteresis Loops and Lissajous' Figures, and on the Energy wasted in a Hysteresis Loop," by S. P. Thompson. "Energy Relations of certain Delectors Used in Wireless Telegraphy," by W. H. Eccles. VOL. CII., No. 2641. HALIDES OF TANTALUM.* By WALTER K. VAN HAAGEN. pound would not be unlikely to appear at some stage during THE CHEMICAL NEWS. the reduction of the pentabromide in hydrogen. At first there seemed no evidence of this. At times, however, the sublimate appeared to be different. Indeed, it had been noticed that toward the posterior end of the tube, i.e., beyond the metallic deposit, there was a slight greenish partly almost black film. It dissolved in water with an intense green colour, and in methyl and ethyl alcohol with the same colour. Its analysis indicated a tantalum tribromide, but Chapin, in the John Harrison Laboratory of Chemistry, has since demonstrated that it is not this, but that it is in reality a bromo-tantalum bromide, (Ta6Br12) Br2 (Journ. Am. Chem. Soc., xxxii., 323). An oxybromide of tantalum was not observed. Efforts were made both by Rose (Pogg. Ann., 1856, xcix., 593) and by Moissan (Comptes Rendus, cxxxiv., 211) to obtain an iodide of tantalum, but without avail. So the query presented itself: is it not possible to transpose tantalum bromide by means of a suitable iodide? Silver iodide suggested itself for this purpose. Accordingly, tantalum pentabromide was distilled through a column of granular well-dried silver iodide in a current of carbon dioxide. A brown sublimate resulted. It contained con siderable free iodine, which was carefully expelled, and the residue analysed. This analysis indicated a pentabromide with unmistakable evidences of combined iodine. How could there be free iodine unless there had been a reduction of the bromide? THE chloride alone of all the possible halides of tantalum has received more than passing attention. A bromide has been recorded, but the iodide is absent from our literature. H. Rose (Pogg. Ann., 1856, xcix., 87) claimed to have obtained the bromide by strongly igniting a mixture of tantalic oxide and carbon in a current of carbon dioxide laden with bromine vapour. He failed to give any analytical results. He surmised that his product was the bromide. Moissan believed it was produced upon heating tantalum metal in a stream of bromine vapour. With pure materials the conditions essential for the satisfactory preparation of tantalum pentabromide may be briefly summarised: 1. Tantalic oxide, previously strongly ignited, should be intimately mixed with an excess of pure carbon, an equal weight of the latter being a convenient and quite sufficient amount. Starch carbon answers well, but it usually leaves an appreciable ash, hence pure sugar carbon is preferable. The excess of carbon indicated makes the mass sufficiently permeable to the bromine. 2. Air should be completely expelled. Raise the charge to a full red heat in a current of carbon dioxide to remove the last traces of moisture. 3. Phosphorus pentoxide is essential as the final drying agent for the carbon dioxide. 4. A high temperature must be maintained during the passage of the bromine, otherwise nearly all of it will escape unchanged. 5. The resulting pentabromide should be fused from time to time in order that the combustion tube may not be obstructed. It is easy to get a yield of about 70 per cent of the theory. The product from the above procedure was re-sublimed in an atmosphere of carbon dioxide. Upon analysis it showed : = Theory. 68.61 Ta = 32.21 32.03 31'79 Br 68.70 68.68 68.38 Tantalum pentabromide consists of yellow elongated lamellæ, curving or clinging to the tube in_beautiful arborescent forms resembling frost flowers. They fuse easily to a transparent ruby-coloured liquid. Their colour is suggestive of that of potassium bichromate. They may be sublimed without melting. The vapour of the bromide is yellow in colour, somewhat resembling that of chlorine. The bromide melts at about 240°, and begins to boil at 320°. It fumes strongly in the air. It dissolves rapidly in absolute methyl or ethyl alcohol, forming at first an amber-yellow coloured liquid which soon becomes colourless. Usually the heat generated causes the alcohol to boil. These reactions certainly point to tantalic esters. Anhydrous ethyl bromide is an interesting solvent for tantalum pentabromide. When the latter is brought into this liquid heat is evolved, and a reddish coloured solution results. If the latter be cooled in water or evaporated in a vacuum desiccator golden-yellow coloured crystals separate. The solution fumes strongly in the air. Tantalum pentabromide may be sublimed in at atmosphere of hydrogen. This is possible at a temperature just sufficient for the sublimation. At more elevated temperatures a partial reduction to the metallic state occurs. If a lower bromide of tantalum should exist such a com*An abstract from the author's doctorial thesis (1909). From the Journal of the American Chemical Soci ty, xxxii.. No. 6. Finally, it was found that the potassium iodide used in the preparation of the silver iodide contained some iodate. Most likely then the reaction had proceeded as follows:7TaBr5+5AgIO3 = TaI5+3Ta205+ 5AgBr + 15 Br2. The liberated bromine set free iodine from the silver iodide and probably from the tantalum iodide, allowing only a small amount of the latter to escape, while by far the greater portion of the bromide distilled over unchanged. This view is further supported by the fact that iodine separates when tantalum pentabromide is distilled through a layer of potassium iodate. Ac Soon The next thought was to try hydrogen iodide. cordingly, tantalum pentabromide was slowly distilled in a steady stream of anhydrous hydriodic acid gas. the reddish colour of the bromide changed to brown, while the escape of hydrobromic acid, together with the excess of the hydriodic acid, could be proved at the exit of the tube. Further, an analysis of the dark brown product showed that only one-third of the bromide had been converted into an iodide. Therefore the experiment was repeated, about 3 grms. of the pentabromide being distilled as slowly as possible in a brisk current of hydrogen iodide for about four hours. The product was brownish black in colour, and showed much iodine. Its tantalum content was found to be 22.98 instead of 22:37 per cent as required by Tal5. The remainder of the preparation was subjected to another distillation in hydrogen iodide, and analysed with these results : ON THE CALCULATION OF OPTICO-CHEMICAL fundamental constants relating to various other groups, nC+2(n+1-a)H + (n − a− 1)L1+aL2= =nA-(n-a-1)B -ar, so that knowing the values of A and B, the values of r can at once be obtained from the molecular refractivities of such hydrocarbons. Thus, amylene is C5H10; i.e., Μα 5A-3B-г, My 24.65, 25'45. гa = 5Aa - 3Ba - 24.65 -3.00, гy = 5Ay - 3By-25 45 2:59. Mean values:-ra = 2'94, гy = 2.62 (see Table V.). = Therefore Using these values, and the values of A and B already obtained, the molecular refractivities (for both Ha and Hy lines) of all the ethylene hydrocarbons considered have been calculated, and are exhibited, together with the differences between them and the experimental, and the percentage errors in Table V. It has been found, using the old method of calculation, that in certain compounds (namely, those containing the >c-c_c-c<) the influence of the unsaturated linking >C=C links is far greater than expected from theory. sideration of this point we must postpone for the present; it must be understood that the above constants refer only to the simple influence of the ethene links. The con With regard to A, the data relative to acetylene hydrocarbons is too scanty to allow of the correct value of this constant being thereby obtained; so that we must postpone the calculation of its value until, with the determination of we are enabled to employ data relating to substituted acetylenes. The approximate value of ▲ can, however, be obtained from the figures given for heptidene. Heptidene is CH12; i.e, 7A 5B 4. Ma 32'46, My=33'39. ThereforeAa=7Aa - 5Ba—32·46=4'33 ; AY=7AY-5BY - 33°39-4'05. 2·62 - 2'94 By - Ba as before. = and also A' - Ay - Aa, B' In a precisely similar manner it can be shown that A'AY Aa = 4'05 4'33=-0.28 (approximately). Hence, the molecular dispersion of any hydrocarbon can be calculated by multiplying the number of ethane links in it by o'13, the number of ethene links by o'32, the number of ethine links by a constant approximately equal to 0.28 (exact value to be determined later), and taking the sum of the products thus obtained. Moreover, if it be admitted that the influence on molecular dispersion of the hydrogen atom and the |