temperature of 180° F. for about two hours. When the tube had cooled, its end was broken off, the fluid contents drained into a small flask, and the solid matter remaining in the tube exhausted of fat by two or three boilings with ether. The contents of the flask were evaporated to about 10 c.c., then ether added to dissolve the fat, the ethereal solution separated, and evaporated to dryness in a very small weighed glass beaker. Before calculating the weight of the fat, the solubility in ether of the residue in the beaker was ascertained. Anyone wishing to try this method of estimating the fat of milk, but who is unprovided with the means of sealing up the fluid in a glass tube, will find one of the long oldfashioned eau-de-Cologne bottles answer the purpose. The bottle must be provided with a very good cork, which must be tied down. The water-bath may be a tall cylindrical tin vessel. The bottle should be immersed to within an inch of its mouth in the water. The following is the ordinary food of a Bengali cow, but the animal in the Bengali's hut plays very much the part of the Irishman's pig, and, with its master, has occasionally to manage as it best can:-About 12 lbs. of rice straw, 2 lbs. of oil-cake, 1 lb. of husks of rice, sometimes a little very poor grazing, the water in which the family rice has been boiled, and about 35 lbs. of water. ABRIDGMENTS OF PROVISIONAL AND COMPLETE SPECIFICATIONS. Improvements in apparatus employed in the manufacture of salt. Otto Ernest Pohl, salt manufacturer and merchant, Liverpool, Lancaster. October 22, 1872.-No. 3116. The object of my invention is to produce salt in a merchantable condition at less cost. For that purpose I proceed as follows:-First. As means for economising fuel I arrange ordinary or convenient evaporating pans, one on the top of or over the other, and pass the flames, heating gases, or products of combustion over the brine at the lower pan, and at the same time under the bottom of the top pan. Doors are provided for withdrawing the salt from the bottom pan. Series of double pans may be used, and the flames, heating gases, or products of combustion and steam led over the brine. Second. As means for providing a cheap and durable cover for evaporating pans I construct such covers of a combination of wood or other suitable material and lead, lead being used to line the wood or other material forming the frame. Improvements in furnaces for burning sulphurous ores. Alfred Vincent Newton, mechanical draughtsman, 66, Chancery Lane, Middlesex. (A communication from Konrad Walter, Augsburg, Bavaria). October 23, 1872.-No. 3142. The grate of the furnace on which the iron or copper pyrites (reduced to a suitable size) is laid is formed of bars which are capable of rocking in their bearings. These bars are made of such a section that when in their normal position the spaces between them will be sufficiently narrow to ensure the retention of the ore in NEWS the grate, but when rocked will open spaces for the discharge of the ore that lies next the bars. Improvements in protecting walls and other erections of brick, stone, iron, and wood from moisture. Robert Knott, chemist, Bolton, Lancaster. October 24, 1872.-No. 3154. This invention consists in the use of glue or similar substances and a salt, as bichromate of potash, to render it insoluble. Improvements in obtaining caustic baryta. Thomas Cobley, Dunstable, Bedford, and John Edgar Poynter, Glasgow, Lanark. October 28, 1872.-No. 3194. In carrying out the invention barium sulphide is mixed with heavy oil or creosotic liquor and submitted to distillation. A combustible gas is obtained, and after being freed from sulphur compounds may be used as an illuminating gas, or as a fuel. The caustic baryta may be washed out of the residue, or it may be applied in many cases in its crude coke-like form. Improvements in the manufacture of white-lead and apparatus therefor. William Thompson, 101, Wandsworth Road, Surrey. October 29, 1872.-No. 3202. This invention relates to improvements in the process of and apparatus used in manufacturing white-lead. The melting pan is made in compartments for regulating the temperature and securing the purity of the blue lead. This lead is made into thin sheets of open texture by pouring it into a revolving cylinder kept cool, and an inclined knife, and receiving it in water. The sheets and and it is granulated by running it in a thin stream between a roller granules are charged on trucks which are run upon rails into the chambers where the chemical reagents act on the lead so as to convert it into white-lead; the trucks charged with the converted lead being run out at opposite doors. Improvements in bleaching textile fabrics and other fibrous materials. Baldwin Fulford Weatherdon, C.E., 77, Chancery Lane, Middlesex. (A communication from John Palliser, Robert McDowell, Adolphe Klopsk, and Victor Grumel). October 31, 1872.-No. 3231. This invention consists in bleaching textile fabrics and other materials, without any previous preparation, by immersing them in a bath composed of chlorine, soda-salt, and sub-carbonate of soda neutralised by exposure to the oxygen of the air for a certain time. Improvements in gas lamp blowpipe apparatus, part of such improvements being applicable to other spirit lamps. John Robert Harper, Clerkenwell, Middlesex. November 1, 1872.-No. 3233. The first part of these improvements consists in so constructing and regulating the aperture or apertures of the jet pipe or burner as to admit of benzoline, paraffine, naphtha, or other analogous oils or spirits being employed for generating gas under pressure in the oil or spirit vessels of gas lamp blowpipe apparatus. Another part of these improvements consists in applying two or more jet pipes to such apparatus, and also in attaching the jet pipes to the oil or spirit vessel of gas blowpipe apparatus by means of a gas union joint or otherwise. Another part of this invention relates to the application of an improved arrangement or construction of safety valve to the oil or spirit vessels of gas blowpipe apparatus. Another part of this invention relates to an improved construction of the wick tubes or holders of spirit lamps of all kinds, for the purpose of preventing the transmission of heat from the flame to the oil or spirit in the reservoir. Another part of these improvements consists in securing the spirit lamp in the case or frame below the oil or spirit vessel by means of a self-acting locking contrivance, which holds the lamp firmly in position. Another part of these improvements consists in so arranging the vessel in which the gas is generated, and the lamp through which the jet is directed, that the flame may impinge and act upon a horizontal surface either above or below the apparatus. Another part of these improvements in gas lamp blowpipe apparatus consists in arranging and mounting a series of such separate lamp apparatus in a case or frame for directing a number of gas jets upon an extensive surface required to be thus acted upon. Improvements in metallic alloys applicable where copper, tin, zinc. brass, Muntz's metal, and other like metals and alloys are now used, Paul Auguste Desjardin, M.D., Paris. November 1, 1872.-No. 3244The metals used in the formation of this improved alloy, or alloys, are copper, tin, zinc, arsenic, and nickel, in various proportions, according to the use and colour required. In some cases one or more of the ingredients are omitted. Improvements in mixing, charging, and smelting iron ores. Edward Withy and William Gibson, West Hartlepool, Durham. November 2, 1872.-No. 3252. The object of this invention is to save fuel as much as possible. In effecting this, in the first place, the ores are crushed and ground, and the smaller they are ground the less fuel they take to smelt them. Second. The pulverised ores are mixed with the required quantity of lime and water to a stiff paste, which paste is forced into moulds or through dies, in a similar manner to drain tiles, the dies being made to give such shape or form to charging sections as will afford the greatest amount of heating surface, according to the weight and strength of the materials. With these sections are charged blastfurnaces, puddling-furnaces, cupolas, and vibratory-furnaces, in manner described in Letters Patent No. 2672, A.D. 1872, and more especially they are used in the improved puddling-furnaces described in said Letters Patent. Improvements in fixing salt pans and in arranging the furnaces under the same. Joseph Parks, Wincham Boiler Works, Northwich, Cheshire. November 2, 1872.-No. 3260. According to this Provisional Specification the pan is supported on pillars, so that the whole or nearly the whole of the bottom becomes available as heating surface. Improvements in the production of oxygen gas. James Alfred Wanklyn, 11, Harrington Street, Hampstead Road, Middlesex. November 2, 1872.-No. 3261. The feature of novelty of this invention consists in utilising the chemical properties of copper and oxide of copper in the preparation of oxygen gas. of chloride of lime. To get an intense black, it is THE CHEMICAL NEWS. necessary to mordant in chloride of manganese at 40° B., VOL. XXVII. No. 706. ON ANILINE BLACK. IN May, 1869, I made public a process for dyeing aniline blacks by means of peroxide of manganese employed as mordant and oxidising agent. The practical application of this process, although it yielded results very satisfactory as regards the beauty and solidity of the blacks, was beset with difficulties, which caused it to be abandoned. But, as in this investigation I came upon several novel facts, it may be interesting for chemists desirous of carrying on further researches in the same field to know the exact conditions of my process and its attendant drawbacks. Dyers are generally of opinion that, to dye yarns uniformly and regularly, drying must be avoided. The fixation and development of colours by means of dryings always gives rise to difficulties which are not encountered when we pass the yarn, without drying, from one bath to another. In dyeing thick bundles of cotton yarn, the interior of the hanks is much less exposed to the air than the exterior, and consequently, if the development of the colour is due to the action of the air, it is very probable that, in spite of the skill of the operator, inequalities of shade will occur. On the contrary, when the yarns are plunged successively into baths where they are uniformly moistened, and where they are in contact with the mordant and the colouring matter, there is much less probability of inequalities. In the case of aniline blacks, the inconveniences of a dry procedure have been already pointed out, and I do not see how they can ever be completely avoided. On the other hand, aniline black, being necessarily absolutely insoluble, cannot be fixed like another colouring matter, but must be formed in the place which it is to Occupy upon the fibre. To mix, with a salt of aniline, oxidising agents. capable of producing the black, and to wash the yarn in such a bath until the colour is developed, is a method which does not yield good results, because the black, instead of fixing itself upon the fibre, remains suspended in the liquid. Mordanting the fibre with an oxidising agent which is soluble, or capable of being rendered so in the dye-bath, equally occasions the development of colour in the liquid, and consequently involves considerable losses. It seemed to me that one method only for dyeing aniline blacks was practicable; fixing a salt of aniline upon the fibre in an insoluble state, and then passing it into an oxidising bath, or, inversely, fixing on the fibre an insoluble oxidising agent, and passing it subsequently into the solution of a salt of aniline. The second modification alone gives useful results; and, practically, it may be reduced to the fixation upon the fibre of oxidising agents rich in chlorine or oxygen, capable of easy decomposition, but incapable of diffusing themselves in the dye-bath and of wasting the colouring compounds with which the bath is charged. The agents in question are the higher oxides of manganese, binoxide and chlorite of lead, &c. Binoxide of manganese has especially attracted my attention. Fixation of the Mordant.-The simplest process for fixing manganese upon cotton, wool, or silk consists in plunging these fibres into the solution of an alkaline manganate or permanganate. These salts are, unfortunately, very expensive. I had recourse, therefore, to the old process for manganese bronze, which consists in soaking the fibres in a salt of manganese (acetate, sulphate, or chloride), then passing them into caustic soda, and oxidising the protoxide of manganese thus fixed by means working the cotton in this bath for an hour, wring out well, then, without rinsing, pass it into boiling soda lye at 12° B., holding lime in suspension. Or the cotton may be first mordanted in a boiling manganese bath, and then passed through cold alkali. After the fixation of the oxide, the cotton is washed in much water, and passed into a lukewarm chloride of lime bath, regulating the proportion of this agent so that it may never be found in great excess, which might injure the fibre. It is best to add the chloride of lime little by little till the manganese bronze is sufficiently intense. At first sight this method seems very practical, and, nevertheless, the difficulties met with have caused the process to be abandoned. The treatment with soda is offensive to the workmen, and roughens the cotton. The oxidation is a delicate process, as it is important not to injure the fibre. In short, if each step is simple, the whole requires precautions which yarn dyers are not accustomed to take. The process, it should be added, has given good results when applied in calico-printing. I have endeavoured to modify the conditions of fixing the manganese. I mention a single remarkable result. A tissue, mordanted with manganese and placed in a chamber filled with ammoniacal gas, is found of a deep brown when taken out, the protoxide of manganese becoming readily peroxidised under these circumstances. Dyeing. The yarns, charged with manganese and well washed to eliminate all uncombined matter, are steeped in a cold acid solution of aniline. The colour is formed almost instantaneously. As soon as the bronze comes in contact with the aniline salt, the reaction takes place. The binoxide of manganese oxidises the aniline, and the black formed takes the place of the metallic compound. The operation is finished in one or two minutes, but the yarn may be left an hour in the bath without inconvenience. The proportions to be employed vary according to the intensity of the black desired. An excess of acid must be always used; thus, to 10 or 20 grms. of aniline per litre 60 grms. of sulphuric acid must be added, or to 50 grms. of aniline 150 of acid. If these limits are much exceeded the mordant may be attacked. The sulphuric acid may be replaced by other mineral acids, such as the hydrochloric, arsenic, &c. When taken out of the dyebath, the cotton is well washed and passed into a boiling alkaline bath-soap or soda-to remove the last traces of acid and give the black its full beauty. Brightening.-After dyeing, the shades may be modified and their intensity augmented by means of different agents. This indicates that, when the binoxide of manganese has completed its action, the colouring matter is still in a transition state, in which further oxidation may be useful. Bichromate of potash, at I grm. per litre, salts of copper, mercury, and chrome, and especially a mixture of chlorate of potash, a salt of copper, and sal-ammoniac (1 grm. of each per litre), increases the intensity of the black. This treatment is applied after the washing subsequent to dyeing, and is carried on for half an hour at a boiling heat. It is followed by a second washing and by boiling in soap-lyes. The process described gives fine, solid blacks; it is speedy, and does not injure the fibre. On the other hand, we must not forget the difficulties of the mordanting process, and the black stains off a little when rubbed. In calico printing, my process is suitable for:-Black grounds. Black grounds, with discharge effects in all colours. Greys, produced by weaker mordants. Black patterns, along with greys and other shades capable of resisting the operations above mentioned (iron, chrome, copper, indigo, catechu, &c.). Joint application of black and indigo. Blue grounds, with white discharge and black patterns. The nature of the coal-tar base employed is very im portant. Pure aniline, used alone, gives a very fine intense black. Toluidine, a blue-grey. Methyl-aniline, | question by some eminent authorities. Thus, Hofmann a violet-black. Naphthylamine, a violet-brown. The differences of shade are so striking that cotton cloth mordanted in this manner may be used to determine the comparative value of commercial anilines. ON PROPYLAMINE AND TRIMETHYLAMINE, AND THEIR THERAPEUTICAL USE. THE particulars in the following account are from a recent article by Prof. Gubler, of Paris: It is nearly twenty years since these two artificial alkaloids were introduced into the "Materia Medica" by an eminent St. Petersburg physician, and yet their existence seems to have been pretty much ignored by the majority of practitioners till quite recently. The experiments of Awenarius, commenced in 1854 and published ten years later, attracted attention from only a few observers; among these an eminent Belgian, M. V. Guibert. Some years later, the Russian doctor Kaleniezenko took up the work commenced by his fellow-countryman Awenarius, and published an interesting monograph on propylamic medicines. While Awenarius had applied propylamine in treatment of acute febrile disease, and specially rheumatism, Kaleniezenko regarded chiefly the alterative action which he considered it to have in chronic disease, especially the manifestations of scrofulous and tuberculous diathesis. He considered that cod-liver oil owed its efficacy to the volatile alkaloids contained in it, and other substances, also containing them among their principal constituents, would act in the same way. The idea is ingenious, but it is neither proved nor probable. In June, 1872, an original memoir on the subject appeared in Italy, and, about the same time, one in America. Both publications excited the curiosity of medical men in France and England, and the therapeutical study of propylamine is now engaging considerable attention on both sides of the channel. Propylamine is an excessively volatile liquid with a strong penetrating odour, like that of ammonia, and which, when diffused in the air, often resembles that from the brine of herring or of sardines. It is soluble in water, which it makes strongly alkaline, combines energetically with acids, and forms salts generally soluble in water and in alcohol, and capable of exhaling an odour of fish when either heated or treated with a fixed alkali. This alkaloid is found in the flower of hawthorn, in the fruit of sorb, in several Chenopodia, in spurred rye, in human blood and urine, and in cod-liver oil. Propylamine and trimethylamine are isomers; their formula is C6H,N, but they differ somewhat in structure. The first may be represented by ammonia, NH3, in which I molecule of hydrogen is replaced by 1 molecule of propylene, C6H; while, in the second, 3 molecules of methyl, C2H3, are substituted for 3 molecules of hydrogen. These differences in grouping are necessarily connected with differences in physical, chemical, and physiological properties. The two forms of C6H,N are commonly found together, and, owing to their extreme volatility and facility of metamorphosis, their extraction and isolation is very difficult. They have not yet been obtained, except in the state of mixture, and probably associated with other ammonia compounds. Moreover, they have only been obtainable in aqueous solution, more or less concentrated; whether by reason of the process of extraction, or the impossibility of preserving in the free state liquids so volatilisable-one of them (propylamine) boiling at +45°, and the other at +5°. They are therefore not administered in the pure state in medicine, and this may account for some of the discrepancy of statement as to their action. Further, the very existence of propylamine in the complex substance used in medicine has been called in has sought in vain for it in the brine of herring; he has only succeeded in finding its isomer, trimethylamine. Silva, indeed, has obtained propylamine, but only in very minute quantity. The uncertainty increases when one reflects that, according to the richness of the brine submitted to distillation, in presence of caustic potash, to expel the volatile alkalies, and according to the manner of the operation, we may obtain solutions more or less charged with active principles. M. Petit's researches have brought to light some curious facts. He subjected to alkalimetric tests several different products sold under the name of propylamine, and with the following results: Using a sulphuric liquor, I c.c. of which exactly saturated 0.06 gr. of propylamine, he found o'2 c.c. of the acid solution was necessary to neutralise I gr. of propylamine F; 03 c.c. for the same quantity of propylamine P; 06 c.c. for the product D; 12 c.c. for A; and 2.5 c.c. for that designated S. Thus, the propylamine S, which contained o'15 c.c. alkaloid per gramme, was more than ten times richer than the propylamine F, which contains only o'012 c.c. There must be considerable disparity of action in medicines so unlike. To all these causes of error should probably be added another, which may not be the last. Propylamine and trimethylamine, in presence of light or in contact with the atmosphere, is transformed gradually, and often quickly, into ammonia properly so-called, NH3, and into one or several other products representing C6H6. In fact, propylamic solutions, immediately after being obtained, give a peculiar sweetish and slightly aromatic odour, approaching that of ammonia, but quite different; whereas, the emptied vessels, several days after, exhale the strong pungent odour of the volatile alkali, and appear, at least, to contain only pure ammonia. Allowing for these sources of difference in observation, the following is what seems most clearly established as to the physiological action and therapeutical effects of propylamine and trimethylamine, or, rather, of propylamic solutions: Propylamine somewhat reddens the surface of the skin, causes a sensation of heat and burning in the first passages, and retards the pulse. Additional experiments are necessary to explain this retardation. The recent observations of Namiais do not solve the problem. He has observed, however, not only a diminution in the number of heartbeats, but a lowering of temperature and increase of the aqueous diuresis; so that he considers the action of propylamine similar to that of digitalis, but undoubtedly superior. He further observed that the pulse, retarded by propylamine, lost, at the same time, in force and fulness, indicating diminution of vascular tension, and, also, it would seem that the circulatory retardation is not produced by the same mechanism in the two cases. Awenarius was the first to apply propylamine in therapeutics. Dr. Gaston, of Indiana, following his example, apapplied the alkaloid in treatment of acute articular rheumatism. Namiais, of Venice, guided, on the other hand, by his own researches, used it as a substitute for digitalis and its active principle, in cases where it was necessary to moderate the circulation and to increase the flow of urine, i.e., in organic affections of the heart, and dropsies dependent on them. More rarely, he has employed propylamine to stimulate perspiration. There followed the researches of Dujardin Beaumetz, Besnier, and several other French physicians. Dujardin Beaumetz does not regard propylamine as a mere sedative of inflammation or of fever, after the manner of quinine, but as an agent for extinguishing rheumatism locally, and repressing its fresh appearance. "Unfortunately, a most attentive and prolonged study of the effects does not allow me to share the convictions of our distinguished colleague. My own experience, somewhat limited as yet, but fortified by that of Pidoux, | by a mixture of sulphuric acid and potassium bichromate. and other practitioners in the City hospitals, reduces the use of propylamine to that of a palliative for articular inflammation and rheumatic fever, which does not prevent relapses, and has not the extraordinary power which we might have desired." For applying to the skin, Guibert recommmends the use of pure propylamine. For mucous surfaces, it should be more or less diluted; for internal use, Awenarius prescribed it in potions of 1 to 4 grms. and more, in 125 grms. of distilled water aromatised with peppermint. This maximum has never been reached by the others. "For my own part, I have prescribed doses varying from I to 3 gr., and with the latter dose, I have only obtained obscure physiological results, and so slight and inconstant a retardation of the blood circulation that I could not affirm that it had the effects of medicinal action. In one case, on the contrary, I observed a general stimulating action, characterised by peripheric heat, pricklings in the skin, a tendency to perspiration, and restlessness in the limbs. But I am unwilling to draw any formal conclusion from this single fact; though it seems quite natural to expect stimulating effects from substances so closely allied to ammonia, and capable of progressive metamorphosis into a volatile alkali." "My provisionary conclusion is this-The concordant facts observed in Russia, Italy, the United States, and France, by eminent clinicians, warrant the belief that propylamic solutions exert a favourable influence on rheumatism and phenomena of circulatory excitation; still, the demonstration of this therapeutical action is not yet furnished, and truly scientific experimentation will only commence when we shall be in possession of one or of several agents well defined and always identical." Taking advantage of the suggestion of Fittig,* with the hope that the ortho-acid would be destroyed by the oxidising agents, I subjected the mixture of the two potassium salts to the influence of sulphuric acid and potassium bichromate in noted proportions. The oxida tion, when once commenced by gently heating over a water-bath, proceeds rapidly to the end without the further aid of heat, and is completed in the course of a few minutes. The liquid becomes very hot, and foams somewhat; an evolution of gas takes place as long as the oxidation-process continues; and its cessation indicates the end of the operation. In order to extract the product from the mixture the whole was diluted with a large amount of water, and chalk added to the point of neutralisation. By this means the chromium oxide formed and the excess of sulphuric acid were precipitated, and in the solution remained the potassium salts of the sulpho-acid or acids, together with some neutral potassium chromate. Baryta-water was now added in sufficient quantity to precipitate exactly the chromic acid present, this filtered off, and the filtrate evaporated almost to dryness. The colourless residue consisted of the potassium salts, together with some potassium hydroxide. The mass was first neutralised with sulphuric acid, and then a sufficient quantity of the latter added to set the sulpho-acids free, care being taken to avoid any large excess. Moderately strong alcohol being now poured upon the mixture, an abundant deposit of potassium sulphate took place. This was filtered off, the salt well washed out with alcohol, and the alcoholic filtrate evaporated down again to a small volume. Potassium sulphate was again deposited. This was filtered off, washed out, &c., and the operation repeated a few times. Finally, the alcoholic solution was boiled for some time with water, and then evaporated to dryness over the water-bath. In this way the sulpho INVESTIGATIONS ON PARA SULPHOBENZOIC acids were obtained in a free state without impurities. WHEN Substituting agents are allowed to act upon toluene, in the case of derivatives containing one substituting group, two products are formed. These are the para- and ortho- varieties. The former is always produced in much larger quantity than the latter. This has been proved by Engelhardt and Latschinoff,* and by Wolkow, in the case of the sulpho-derivatives. Wolkow proved that the products belonged to the para- and ortho-series, by converting them respectively into paraoxybenzoic and salicylic acids. According to the experiments of the chemists mentioned, the two sulpho-acids can be separated by partial crystallisation of the potassium salts. In this way the para-salt was obtained in a perfectly pure condition, while the ortho-salt could not be freed entirely from the para-salt. Now, as it had been shown that the oxidation of the mono-brom- and mono-chlor-derivatives of toluene yielded corresponding derivatives of benzoic acid, the idea naturally suggested itself that similar treatment of sulphotoluenic acid might yield the desired derivative of benzoic acid. My best hopes were satisfied. After a few experiments it became evident that by means of this reaction I could prepare parasulphobenzoic acid in unlimited quantity with but comparatively little labour. The principal difficulty that presented itself was to be looked for in connection with the fact that the sulpho-acid is exceedingly easily soluble; and some method had to be devised to extract it from the oxidising mixture, provided it were formed. A preliminary experiment, made with a small quantity of the potassium salts of the sulphotoluenic acids, showed that they were easily acted upon Zeitschrift für Chemie, N. F., 5, 615. +Ibid., N. F. 6, 321. The acid barium salts were prepared, and, on bringing their solution to the point of crystallisation, large acicular crystals were at once deposited, and these possessed the characteristics of the acid barium salt of parasulphobenzoic acid already described. They were analysed with the following results : 0'5415 grm. salt was heated above 200°, and lost 00495 grm. H2O; and gave o°2130 grm. BaSO4= =0'12524 Ba. Found. Calculated. 593 The This shows, then, conclusively that by the oxidation with sulphuric acid and potassium bichromate, the sulphogroup of parasulphotoluenic acid remains intact. conduct of the ortho-acid under like circumstances I shall refer to below. As far as I have been able to discover, by a consultation of the literature, this is the first attempt which has been made to oxidise sulpho-acids in the manner described. The simplicity of the reaction and the satisfactory character of the results lead me to desire the further application of the principle involved, and I shall take the first opportunity to prepare a pure sulphoxylenic and sulpho-mesitylenic acid, with the object of subjecting them to the influence of oxidising agents, hoping thus to obtain an oxybibasic and an oxytribasic acid. After having gained the necessary preliminary knowledge, I proceeded to determine the best conditions for the reaction. A large number of experiments were made, and as the result I would give the following directions:Instead of first preparing the potassium salts of the sulphotoluenic acids, I employed a solution of the acids in sulphuric acid, considerable labour being thus saved. 25 grms. of pure toluene are dissolved in 200 grms. of * Ibid., N, F. 7, 179. fuming sulphuric acid without the aid of heat. When this solution has cooled down somewhat, two volumes of water are added, and the height of the liquid in the flask marked. Now more water is added, and the mass subjected to distillation until the liquid has reached the original volume indicated by the mark on the vessel. In this way any toluene which may have remained unacted upon by the sulphuric acid is removed. The solution is now allowed to cool to the ordinary temperature, and then 160 grms. of coarsely-powdered potassium bichromate gradually added. In order to start the oxidation the flask is placed on a water-bath, and gently heated for about ten minutes. During this time a commotion is noticed in the liquid, which gradually increases. An active foaming ensues, and when this has fairly begun the flask is removed from the water-bath. A uniform evolution of gas continues until the end of the operation, which occupies usually about twenty minutes in all. The gas evolved is carbonic acid, as was proved by appropriate reactions. In heating the mixture at first, it is absolutely necessary to place it on a water-bath; if the attempt be made to heat with a flame the flask invariably breaks. This is occasioned by the fact that the potassium bichromate lies at the bottom of the flask, and that the oxidation commences and goes on rapidly just at the spot where the heat from the flame is strongest. This spot immediately becomes very hot before the remainder of the glass has been at all heated, and from this spot a circular piece of glass inevitably drops, followed by the contents of the flask. When the operation is at an end, which, as stated, is indicated by the cessation of the evolution of gas, the whole is diluted with water, and then treated successively, as above described, with chalk, baryta-water, sulphuric acid, and alcohol. By this method, in the course of a few days, a very large quantity of pure acid barium parasulphobenzoate can be prepared. SO2.OH CO.OH' Parasulphobenzoic Acid, C6H4 is prepared from the barium salt by precipitating the barium exactly with pure sulphuric acid, and evaporating the solution. It is very easily soluble in water, and crystallises from a very concentrated solution in the form of beautiful, colour less, transparent needles. These, though very easily soluble, are not deliquescent. They fuse above 200°, but undergo decomposition before the fusing-point is reached. The meta-acid is deliquescent. NEWS The remarkable fact will be noticed that the water of crystallisation is not driven off entirely until a high temperature (320°) is reached. All other salts of this acid, as well as of the meta-acid, which contain water of crystallisation, exhibit the same property, though not in such a marked degree as this one. Barium Parasulphobenzoate, CH4SO5.Ba+2H20. — This salt was obtained by neutralising a solution of the acid salt with barium carbonate. It is moderately easily soluble in cold water, very easily in hot water. It crystallises in small needles, which are grouped together in verrucose masses. The corresponding salt of the metaacid is also easily soluble in water, but according to the descriptions given it contains no water of crystallisation. The analysis resulted as follows: 04174 grm. salt, dried over sulphuric acid, on being heated gradually to 190°, lost 0'0411 grm. H2O; and then gave 0.2587 grm. BaSO4=0'15212 grm. Ba. Acid Barium Parasulphobenzoate,— -The methods of preparation and analysis of this salt have already been given in detail. It is by far the most characteristic salt of parasulphobenzoic acid, and its properties are such as to render its preparation in an absoiutely pure condition very simple. It is exceedingly difficultly soluble in cold water. When perfectly pure the length of the crystals is only dependent upon the depth of the liquid in which they are formed. It is more difficultly soluble, both in cold and in hot water, than the meta-salt. Like the meta-salt it does not give off its water of crystallisation entirely below 200°, and it may be subjected to a much higher temperature without the danger of decomposition. Calcium Parasulphobenzoate is an amorphous powder which is somewhat more easily soluble in cold water than in hot, and is hence thrown down when a concentrated cold solution is boiled. When the potassium salts, obtained in the preparation of acid barium parasulphobenzoate by evaporating the solution which has been treated with chalk and barytawater, are fused with potassium hydroxide, a mixture of Potassium Parasulphobenzoate, prepared by neutralising Acid Sodium Parasulphobenzoate,— C6H4 SO2.ONa CO.OH +2H2O. This salt was prepared by neutralising and precipitating the acid barium salt with sodium carbonate, and then adding hydrochloric acid to the solution, evaporating, and allowing to crystallise. It forms beautiful, long, colourless, lustrous, stellate prisms. It is moderately easily soluble in cold water, more easily in hot water. The corresponding salt of the meta-acid is more difficultly soluble in cold water, and crystallises in laminæ. The two, when present in the same solution, cannot, however, be separated. The analysis of the salt gave the following results: 0'3707 grm. of the salt, dried over sulphuric acid, on being heated gradually to 310°, lost o 0607 grm. in weight; and then gave 0.102 grm. Na2SO4-0033038 grm. Na. (C2H2SOs) Na 21H2O Calculated. Found. cylic acid forming in some cases fully half of the product. This fact taken alone led at first to the conclusion that the methyl groups of both the para- and ortho-sulpho acids had been oxidised; and that thus not only parasulphobenzoic acid had been formed, but at the same time orthosulphobenzoic acid. Further investigation, however, showed conclusively that this was not the case, but proved another interesting fact, of which I shall speak below. IV. Formation of Terephthalic Acid from Parasulpho benzoic Acid. The recent experiments of V. Meyer* have tended to materially modify the prevalent views in regard to the constitution of the bi-derivatives of benzene. Meyer showed that ordinary sulphobenzoic acid, which, on the one hand, could be converted into oxybenzoic acid, could, on the other hand, be converted into isophthalic acid by fusing its potassium salt with sodium formate. As, according to the reigning ideas, isophthalic acid can only have the constitution indicated by the 13 position of its carboxyl groups, it became evident that oxybenzoic acid, which up to that time had been looked upon as belonging to the same series as phthalic acid, viz., the ortho (12) series, in reality belonged to the meta (13) series, of which Berliner Berichte, iii. jahrgang, 112; and Ann. d. Chem, u. Pharm., clvi., 265. |