270 CHEMICAL NEWS, British Association Committee on Commercial Phosphates. Ce 13, 1875. Anhydrous Acetic Acid.-M. Berthelot.-Already noticed. Structural Formulæ in Space.-J. H. Van't Hoff.An examination of the relation between asymetric carbon and active optical power, and between asymetric carbon and the number of isomers. MISCELLANEOUS. Organisation of the United States Board appointed to Test Iron, Steel, &c.-A Board has been appointed by the Government of the United States "to determine by actual tests the strength and value of iron, steel, and other metals which may be submitted to it, or by it procured, and to prepare tables which will exhibit the strength and value of said materials for constructive purposes." It has standing committees on abrasion and wear, on armour plate, on chemical research, on chains and wire ropes, on corrosion of metals, on the effects of temperature, on girders and columns, on metallic alloys, on physical phenomena, on steels produced by modern processes, &c. The constitution of this Board may be taken as an additional proof of the growing conviction how largely the power and the prosperity of nations depend on physical science. Plattner's "Manual of Blowpipe Analysis."-Mr. D. Van Nostrand, the American publisher, writes:-I have just received from London what purports to be a translation of Plattner's "Blowpipe Analysis," which, upon examination, proves to be an exact reprint, word for word, of Prof. Cornwall's translation published by me. It is translated and edited, or purports to be, by T. Hugo Cookesley, and gives no credit to Prof. Cornwall, but merely says a translation has been published in New York, which he has followed to some extent. I have just issued the subjoined : Correspondence from St. Petersburg.-M. W. Louguinine. In the seventh volume of the Journal of the Russian Chemical Society M. Mendeleeff describes the deposits of spherosiderite at Kromy, in the Government of Orel. MM. Kamensky and Lund communicate analyses of the iron ores of Gytomir, which contain 59 per cent of metallic iron. M. Beketoff communicates, on behalf of M. A. Elketoff, a paper on the transformation of bromide of isobutyl into bromide of tertiary butyl under the influence of high temperatures. M. Beketoff, on behalf of himself and of M. Tscherny, communicates a note on the dissociation of suiphuretted, seleniuretted, and telluretted hydrogen; and, on behalf of M. Kousmensky, a note on the action of oxide of silver upon chloride,bromide, and iodide of lithium. M. Stcherbatscheff treats on the influence of the chloride of sodium on the dissociation of hydrated sulphate of soda in solution. M. Moun has examined the amount of coke yielded by three isomeric bodies-Swedish filter-paper, starch, and gum. The first, when submitted to destructive distillation, yields 6.73 per cent of carbonaceous residue; the second, 1130; and the third, 2014. M. Alexeeff gives a preliminary communication on the mutual solubility of liquids. The solubility of amylic alcohol in water decreases as the temperature increases, whilst the solubility of water in this alcohol augments under the same conditions. The second part contains an important investigation by M. Schöne on the peroxide of hydrogen contained in the atmosphere. M. Morkownikoft publishes a memoir on the oxidation-products of oxybutyric acid. M. N. Zalomanoff communicates experiments on a new method of determining the absorbent power of different soils. He proceeds by filtration, and concludes that the agitation method gives erroneous results. He cannot confirm Liebig's view that the drainage water represents the water in the soil. M. Beketoff publishes a note on the influence of the weight of elements on the reactions of substitution or double decomposition. Progress of the Sulphuric Acid Manufacture in London.-D. VAN NOSTRAND, Publisher, New York, England.-M. G. Lunge. No. 9, May 5, 1875. Researches on the Carbon of White Cast-Iron.MM. Schützenberger and A. Bourgeois.-Already noticed. Unequal Action of Various Isomorphs on the Same Saturated Solution.-M. Lecoq de Boisbaubran. Noticed elsewhere. Substitution of Mercury for the Hydrogen of Creatin.-R. Engel.-Already noticed. NOTICE TO THE TRADE.-An English reprint of my edition of Plattner's "Manual of Qualitative and Quantitative Analysis with the Blowpipe" having appeared in London, I would hereby caution the trade against introducing the same into the United States, as under the copyright laws parties so doing would render themselves liable to legal damages, as well as to confiscation of all copies so imported and placed on the market. This English edition purports to be edited by one T. Hugo Cookesley, but with the exception of the omission of a few tables, and of some other matter of slight importance, it is a verbatim reprint of my edition, translated by Prof. H. B. Cornwall, of Princeton College. This " pirated edition is published by Messrs. Chatto and Windus, of May 17. The British Association Committee on Commercial Phosphates and Potash Salts.-No small amount of correspondence has appeared in our columns on the determination of phosphoric acid and on the discrepancies existing between the respective results of "high" and of "low" analysts. Our readers, doubtless, will be glad to find that steps are being taken towards the removal of a state of things discreditable to analytical chemistry and to its professors, and certainly injurious to an important and growing commerce. At the last meeting of the Stability of the Salts of the Fatty Acids in Presence British Association, a committee, consisting of Messrs. of Water.-M. Berthelot.-Already noticed. Les Mondes, Revue Hebdomadaire des Sciences. This number contains no original chemical matter. No. 17, April 29, 1875. Electricity of Mineral Springs.-M. Thury.-Two platinum electrodes were plunged, the one in the great mineral spring of the Stadthof, and the other in the river Limmat. When connection was made the mineral water was found to be strongly electro-negative. If water was allowed to cool, and artificially re-heated, no current was produced. Bulletin de la Societe d'Encouragement pour l'Industrie This issue contains no chemical matter. E. Dewar, A. Fletcher, E. C. Stanford, and A. H. Allen, was appointed "for the purpose of examining and reporting upon the methods employed in the estimation of potash and phosphoric acid in commercial products, and on the mode of stating the results." Among other steps, the Committee have addressed a circular to all Fellows of the London Chemical Society, and, we hope, to other gentlemen engaged in, or conversant with, the analysis of manures, soliciting information. Among other questions, they ask-"Will you give the Committee the details of the process you habitually employ for the estimation of the phosphoric acid in commercial phosphates? What length of time does the process require? Are you of opinion that the method gives strictly accurate results? If not, will you state the direction in which the error occurs and its maximum extent?" If these and the succeeding questions meet with replies from experienced practitioners in this department, a body of most valuable i information will be collected. After comparing the Patents. answers, and bringing conflicting views, if such should 271 hold, along whose keelson runs a perforated wooden box rator forming part of the pump, and the carbonic acid gas and solution of salt pass at once down a metal pipe to the material. The agent, therefore, for the extinction of fire which admits of the gas passing through to the burning is dry carbonic acid gas, which has no action on cargo. A well-appointed steamer conveyed the party from Blackwall to Greenhithe, where a large wooden barge had been prepared for the experiments. Its entire hold was covered rarily-raised and by no means air-tight wooden deck, with to a depth of several feet with wood shavings, cottonloosely-fitting boards, formed the wide hatchway covering. waste saturated with turpentine, and naphtha. A tempoAfter the apparatus had been explained by Dr. Moffat, its action as a common wash-deck-pump and fire-engine for efficiently, throwing water a distance of at least 30 feet, the pipes to the chemicals were attached, and the signal fire above board had been observed, when it acted very given to set fire to the inflammable materials in the hold.Immediately the flames ran along the entire cargo and issued above the temporary deck, which was then covered with boarding. The pyroletor having been brought into action, and although nearly half a gale of wind was blowing, the fire was completely extinguished in four minutes. The experiments were efficiency of the apparatus so apparent, that the party at once agreed to sign a memorial to ask Government to so completely successful, and the compel all long-passage ships conveying passengers and cargo to carry one of these instruments. It is computed that a 1200-ton ship requires about half-a-ton of each of the chemicals, which, with their packages, cost about £20 PATENTS. ABRIDGMENTS OF PROVISIONAL AND COMPLETE Programme de la Société Hollandaise des Sciences à Harlem, Année 1875.-We learn that the Council of the Society have made a donation of 2000 florins to the Netherlands Society for the encouragement of industry, to be applied in the purchase of objects for the Museum of Industrial Arts. The Société Hollandaise has also contributed towards the erection of monuments in honour of of two of its foreign members, Elie de Beaumont and Quetelet, and to the foundation of a Leeuwenhoek medal, to be awarded decennially for the most important microscopic researches on inferior beings. The following subjects have been proposed for prizes:-For January 1st, 1877.-(1). Complete account of the development, structure, and manner of life of the Ophioglossæ, as compared with the other ferns. (2). A historical and critical study, based upon personal observations and experiments, on the influence which light exerts on the vernal growth of plants. (3). As boats descend a river more rapidly than the water in which they are plunged, the question arises, what influence this circumstance has upon the vertical floats employed to measure the speed of the current. (4). An exhaustive study of the causes to which the luminous phenomena of phosphorescent minerals are due. (5). The extent in the Netherlands of the fossiliferous stratum known as the Eemian system (of Harting), accompanied by a collection of its animal and vegetable fossils and an account of its relations with other known deposits. (6). A methodical study of the influence of stretched cords upon the acoustic properties of halls. On January 1st, 1880.(7). What is the influence of the moon upon the position of the magnetic needle? Essays on the following subjects must be sent in by January 1st, 1876 :-(8). Exact researches on the solvent power of water and of water charged with carbonic acid upon gypsum, limestone, and dolomite at various pressures and temperatures, and in method of manufacturing and concentrating sulphuric acid by reducing This invention describes a the case of the simultaneous presence of common salt and the size of the leaden chambers ordinarily employed, but increasing of other soluble salts widely distributed in nature. (9). A their surfaces by filling them with stoneware vessels, by sprinkling similar set of researches upon silica and natural silicates. these vessels with the acid in process of manufacture; also a modification of the Gay-Lussac tower for denitrification and concentration (10). A critical examination of researches on the peptones by superheated steam acting on porcelain vessels over which the acid of different albumenoid matters completed by original inis trickling, and kept away from contact with the walls of the chamber. vestigations. (11). An exact determination, in Weber's therein, and for the manufacture of gas for illuminating and heating Improvements in treating metals and their alloys by subjecting them to the action of liquids, gases, vapours, and in apparatus employed units, of the resistance of a column of mercury of a metre in length and a square millimetre in section. (12). An purposes. Wade Hampton Smith, civil engineer, Edgbaston, Birming experimental investigation of the relation between electro-acid, and iodine in a fluid state, and the gases and vapours resulting ham, Warwick. August 15, 1874.-No. 2815. The inventor uses magnetic and electro-static unities. (13). New experi- coal-gas, nitrogen-gas, and atmospheric air in such proportions as wood-naphtha, hydrocarbon, hydrochloric acid, nitrous acid, nitric ments on the influence of pressure upon chemical action. from any or all of the above liquid matters, carburetted hydrogen or The memoirs may be drawn up in Dutch, French, Latin,provements, each of the before-named fluids are placed in separate English, Italian, or German, but must not be written in Germay be required, combined or uncombined. In carrying out the imman characters-a very wise precaution. We cannot help remarking that we have little faith in the efficacy of prizes offered to stimulate research. It has been humourously said that you cannot bribe a barren hen to lay eggs. The rewards proposed should, at any rate, amount to a fair remuneration for the time that the required investigations must necessarily engross, but of this they fall lamentably short. Chancery Lane, Middlesex. into a passage through which a current of atmospheric air, gas, or Letters Patent granted to the inventor and J. T. Kirkwood, dated Paton and Harris's Pyroletor, for the Extinction of and, secondly, in machinery and apparatus consisting of wings and a tail, which can be placed at different angles and in different positions, so as to direct and control the movements of the balloon. Improvements in the manufacture of cement. Granville Hamilton Forbes, Clerk in Holy Orders, Broughton Rectory, Northampton. August 15, 1874.-No. 2822. My present invention is an improvement upon the invention for which I made application for Letters Patent July 7, 1874.-No. 2374. According to the said former invention I intimately combine coke or its equivalent with chalk and clay with or without tar, for the purposes of manufacturing cement. According to my present invention I intimately combine coke, or coke-breeze, or an equivalent of the same, or coal or coal aust with chalk, or limestone, or quicklime, with or without tar for the purpose of manufacturing cement. Improvements in the treatment of alizarin for the production of different colours or hues therefrom in dyeing and printing. Félix De Lalande, civil engineer, Rue d'Enfer, Paris. August 18, 1874.-No. 2841. This invention consists in treating alizarin with various oxidising agents in order to obtain therefrom colours or hues in dyeing and printing differing from those obtained from alizarin without such treatment. One method of operating consists in mixing together dried and pulverised alizarin, arsenic acid, and sulphuric acid in given proportions; heating the compound; and boiling the same with water, after which it is filtered and washed. In place of the arsenic acid, antimonic acid, or peroxide of manganese, or stannic acid may be employed. According to another method dried pulverised alizarin is mixed with concentrated nitric acid, refrigerated by means of ice, and after a few minutes the mass is poured into cold water, and the precipitate is collected and washed. According to another method the alizarin suspended in water is treated with bichromate of potash or peroxide of lead, nitrate of copper, nitrate of mercury, mercurous nitrate, perchloride of iron, sulphate of peroxide of iron, or nitrate of peroxide of iron. According to another method alizarin-paste is mixed with sulphate of copper, chlorate of potash, and siliceous sand; the mixture is heated in a vapour-stove for several days, and is then treated with water to remove the soluble salts, and the colouring matter is extracted by caustic soda, and precipitated by an acid. Improvements in the treatment or manufacture of cast-iron. George Gordon de Luna Byron, Chancery Lane, Middlesex. August 22, 1874. -No. 2883. This consists in alloying cast iron while in a molten state with copper, tin, zinc, manganese, and antimony. This flux is melted in a crucible, and mixed with iron, whereby the oxides, sulphur, and phosphorus are removed, and reducing the carbon therein. Improved disinfecting or fumigating candles and pastiles. Frank Wirth, of the firm of Wirth and Co., Frankfort-on-the-Main, Germany. (A communication from William Ressig, Ph.D., Darmstadt, Germany.) August 22, 1874.-No. 2884. The object of this invention is to obtain candles and pastiles which when ignited give off a continuous current of sulphurous acid gas for disinfecting and fumigating purposes. A new and improved process for the manufacture of sulphur-acids, and of sulphites, bisulphates, and sulphates. Alfred Payne, manufacturing chemist, Wolverhampton, Stafford. August 24, 1874.-No. 2893. The inventor burns sulphur or sulphur-ores in a close kiln, admitting only sufficient air for the proper combustion of the sulphur. He inserts one or more pipes into the crown of the kiln, which (after traversing suitable refrigerators) are attached to one or more forcepumps, by which the sulphurous acid fumes are drawn off from the kiln as fast as generated, and forced or projected through one or more outlet-pipes into the vessels containing the material to be operated upon. He produces sulphites and bisulphites directly in this way, and thus avoids the use of sulphuric acid in their production. The inventor produces sulphuric acid by oxidating liquid sulphurous acid (formed by injecting sulphurous fumes into water) by means of nitric acid or other suitable oxidating agents. The inventor produces sulphates by first forming sulphites by the before-mentioned process, and then oxidating by agitation with atmospheric air, or by means of other suitable oxidating agents. This Pro An improved white metallic alloy. Louis Victor Léniau, merchant, Place de la Bourse, Paris. August 29, 1874.-No. 2954visional Specification describes a white alloy composed of copper, nickel, bismuth, zinc, malleable iron, and tin. Improvements in the manufacture of sulphate of soda and of sulphate of potash. Arthur McDougall, manufacturing chemist, of the firm of McDougall Brothers, Manchester and London. September, 2, 1874. -No. 3003. In the manufacture of sulphate of soda and of sulphate of potash by the direct action of sulphurous acid upon the chlorides of sodium and of potassium, great expense and trouble is caused by the usual process of moulding and breaking the moulded salt into lumps, so that when placed in the saturation-cylinders a free passage is allowed for sulphurous acid gas. My invention consists in maintaining the salt in motion whilst exposed to the action of the sulphurous acid gas by the use of suitable mechanical means, so that the salt may be employed in a loose state, and thus save the trouble and expense of preparing lumps, and also cause a more rapid completion of the decomposing action. I also introduce steam in a superheated state during the process; by this means a more rapid action takes place, and the necessary temperature is more easily kept up. Improvements in apparatus for the manufacture of sulphate of soda and sulphate of potash. William Hunt, manufacturing chemist, Castleford, near Normanton, York. September 2, 1874.-No. 3005. This invention has reference to that process of manufacturing sulphate of soda and sulphate of potash, in which chloride of sodium or chloride of potassium is decomposed by a mixture of sulphurous acid gas, air, and steam; and the said invention consists in erecting the chambers in which the chloride is decomposed immediately over the pyrites burners. The hot gases from these burners pass out through the arches of the burners, and travel under and in contact with the floors of the chambers. By this invention the bottoms of the chambers are maintained at a high temperature, which is communicated to the {CHEMICAL NEWS, June 18, 1875. gaseous mixture as it circulates through the chambers, and the requisite high temperature is preserved. Improvements in the manufacture of stearine, with the object of transforming oleines or oleic acids into crystalline substances, which may be employed either to make candles or soap, or for other purposes; and for extracting the solid matter that the oleic acids contain in solution, and thus to render them more limpid. William Morgan-Brown, of the firm of Brandon and Morgan-Brown, engineers and patent agents, Southampton Buildings, London. (A communication from Edward Bastie, chemist, Rue Gaillon, Paris.) September 3, 1874.-No. 3021. This invention describes a method of transforming oleine or oleic acids into eláidine or elaidic acid by putting these bodies in intimate contact with reagents which produce the reduction of any peroxide or any hydrogenic acid, with allotropic or nascent hydrogen, or any decomposition, chemical or electric, of water made by chlorine or other Improvements connected with the process of coating steel, iron, and cast-iron with gold, silver, and other metals or alloys. Jacob Baynes Thompson, Whitehall, Wraysbury, Bucks. September 4, 1874.-No. 3033. The invention consists in protecting the articles to be coated on their passage from the "cleaning-vat to the "plating-vat" by applying thereto a thin film of aluminium or aluminium slightly alloyed. substances. NOTES AND QUERIES. Our Notes and Queries column was opened for the purpose of giving and obtaining information likely to be of use to our readers generally. We cannot undertake to let this column be the means of transmitting merely private information, or such trade notices as should legitimately come in the advertising columns. Magnesite and Bauxite.-Can any of your subscribers inform me where I can obtain magnesite and bauxite, as I wish to possess some of these materials ?-S. E. G. Fish Oils.-I desire practical directions for testing the purity of the most common fish oils. Can any of your readers kindly refer me to some publication where I may find such ?—G. C. Analysis of Sugar.-Could any of your readers inform me where I could see an account, in English, of Dr. C. Scheibler's new process for the valuation of raw sugar by the use of alcohol? By giving the above information they would greatly oblige.-J. W. M. Phosphorescent Powders.-Will your readers kindly furnish me with answers to the following questions?-(1) What is the composition of the phosphorescent powders of various colours advertised in your columns? (2) What is the cause of the phosphorescence which these powders assume for a short time after their exposure to light? I am not aware that the powders are patented. They smell strongly of sulphur.-A. F. London: LONGMANS & CO. RECENT CHEMICAL DISCOVERIES. SECOND SUPPLEMENT to DICTIONARY of CHEMISTRY, bringing the Record of Chemical Discovery down to the end of the year 1872; including also the more Important Additions to the Science made in 1873. By HENRY WATTS, B.A., F.R.S., F.C.S., assisted by eminent Scientific and Practical Chemists. The ORIGINAL WORK, in 5 vols. 8vo., price £7 3s. NEW EDITION OF PROFESSOR TYNDALL'S WORK Now ready, in post 8vo., with Plate and many Woodcuts, 10s. 6d., EAT A MODE OF MOTION. Вy JOHN TYNDALL, LL.D., D.C.L., F.R.S. New Edition, being the HE Fifth. "Beyond question the best and clearest popular exposition of the dynamical theory of heat that has yet been given to the public."Spectator. London: LONGMANS & CO. GEO EOLOGY.-Elementary Collections to illustrate the new edition of Lyell's "Students' Elements of Geology," and facilitate the important study of this science, can be had at 2. 5. 10, 20, 50, to 1000 guineas. Also single specimens of Rocks, Minerals, Fossils, and recent Shells. Geological Maps, Hammers, all the recent publications, &c., of J. Tennant, Mineralogist to Her Majesty, 149, Strand, London. Practical Instruction is given in Geology and Mineralogy by Pro fessor Tennant F.R.G.S., at his residence, 149, Strand (WIC), THE CHEMICAL VOL. XXXI. No. 813. Titanium was carefully tested for without obtaining any NEWS. indication of its presence. NOTE ON SOME CRYSTALLINE In addition to the crystals large quantities of a lustrous laminar substance were discovered in the "horse." This laminar mass contains a very high percentage of graphite and of silica; over 40 per cent graphite, and nearly 30 silica. The rest consists chiefly of a mixture of metallic iron, sulphide, and oxide, of which the oxide is much the PRODUCTS OBTAINED FROM A BLOWN-OUT larger constituent. ON recently blasting out, in the Middlesborough district, the mass of metal, slag, &c., which gradually collects beneath an iron furnace, and is technically known as the "dead-horse," a quantity of bright crystalline matter was found immediately below where the hearth had been when the furnace was in operation. The crystals belong to the octahedral system, are light grey in colour, and of various sizes, some of them being very large. It is almost certain that the mass of slag, &c., with which they were associated has been for ten or twelve years continuously at a temperature not much below that of the melting-point of cast-iron. They are apparently homogeneous, but may readily be separated under the pestle into a dark coloured, easily pulverised, and comparatively lustreless portion, and into little irregular masses, which are malleable, and when beaten out light coloured and highly lustrous. This malleable portion forms one-third of the larger crystals, and nearly twofifths of the smaller. It is tolerably uniform in composition as the following analysis made on portions (No. 1, obtained from a large crystal of sp. gr. 5'48, and No. 2, from a small one, sp. gr. 4.89) will show : No. 2. 94'48 The production of these substances in the "dead-horse from the original cast-iron which had found its way there from the furnace, may be explained by supposing that as this iron gradually cooled, the carbon has separated out in the form of graphite, ascended through the mass of metal, slag, &c., and thus become concentrated in the upper layers, much in the same manner as it is sometimes found on the surface of slowly cooled iron. The conditions existing in the "horse" would be greatly more favourable for such a separation than when the iron is exposed, owing to the extremely slow rate at which the mass cools. The highest part of the "horse" would, according to this view, contain the largest percentage of graphite, and as we descended this would become more and more mixed with iron, giving rise, indeed, to products similar to those now before us. The octahedral character of the crystalline mass is evidently due to the iron, which, under the favourable conditions of a prolonged exposure to an intensely high temperature and a subsequent slow cooling, has assumed its normal crystalline form notwithstanding the large quantity of graphite with which it was mixed. My thanks are due to Professor Thorpe, to whom the specimens were originally sent, for his advice and assistance; and to Dr. Parkinson of Bradford, from whom they were received, for information concerning the circumstances under which they were found. 3'52 REPORT ON THE DEVELOPMENT OF THE CHEMICAL ARTS TH. GRAHAM, who, in his classical researches, investigated the laws of the escape of gases through narrow apertures, made known in 1866 that air which is drawn through a fine chink in a plate of caoutchouc passes in the constant proportion of 416 per cent of oxygen to 58'4 per cent of nitrogen, the half of the atmospheric nitrogen being held back. This mixture causes glowing chips of wood to burst into flame. Deville tested the industrial value of this process, and found that the time required was too long. Absorption has been utilised in two distinct forms. Montmagnon and De Laire in 1868 took out a French patent, based upon the observation of Angus Smith§ that charcoal absorbs from the air more oxygen than nitrogen. According to them, 100 litres of wood-charcoal absorb 925 litres of oxygen, and only 750 litres of nitrogen. If moistened with water, they give off 350 litres of oxygen and 650 litres of nitrogen, so that 575 litres of oxygen and 55 (100?) litres of nitrogen remain and can be extracted with the air-pump. By repeating this process with the same gaseous mixture, they succeeded in bringing the oxygen almost in a state of purity. Whether this process has ever been carried out on the large scale is not known. An attempt has, however, been made with Mallet's * "Berichte über die Entwickelung der Chemischen Industrie Während des Letzten Jahrzehends." Graham, Comptes Rendus, lxiii., 471. § Angus Smith, Proc. Roy. Soc., xii., 424. 274 Estimation of Phosphoric Acid. CHEMICAL NEWS, June 25, 1875. method, based on the property of water to absorb oxygen, ON THE ESTIMATION OF PHOSPHORIC ACID rather than nitrogen. The coefficients of absorption of the two gases are 0'025 for N, and 0.046 for O. If multiplied by the proportion of their bulk in the atmosphere, o'79 for N, and 021 for O, these numbers give the volume-proportion of both gases in water=0.0197 N and o'0097 O; or, the air absorbed in water contains, in one volume, 0'67 N and 033 O. If the unabsorbed nitrogen is allowed to escape, and the absorbed gaseous mixture, richer in oxygen, is withdrawn from the water and again absorbed, it follows, from the multiplication of the two coefficients of absorption with the volume proportions o'67 N and o'33 O, that the gaseous mixture now taken up has the composition 0'525 N 0'475 O; a third absorption raises the result to 0'375 N: 0.625 O; a fourth to o 25 N: 075 0; and a fifth to o 15 N : 085 0, the proportion in which the two gases occur in Tessié du Motay's oxygenous mixture. After the eighth absorption, the gas is almost pure oxygen (0.973 O and o'027 N). Mallet's apparatus consisted of a larger or smaller number of strong iron water-holders connected with each other by means of suction- and forcing-pumps. Into the first air is driven through fine apertures at a pressure of about five atmospheres. The unabsorbed nitrogen escapes by a valve. The absorbed gas is now extracted by the second pump from the first receiver and forced into the second. With a series of four receivers the operation lasts five minutes. If the receivers serially decrease in size, the first holding 10 cubic metres and the last 5, the result of a continuous working of the process is 7760 litres per hour of a gaseous mixture containing 75 per cent of oxygen, or 168 cubic metres in twenty-four hours. The cost of working, wear and tear, and supervision are said to be insignificant. Where motive power is cheap, i.e., waterpower or the waste heat of metallurgical processes, this method may consequently be applicable, especially for use in such metallurgical operations where a mixture comparatively poor in oxygen is serviceable. If we sum up the results of our survey of the methods for the industrial preparation of oxygen, we must place Tessié du Motay's process in the first line, as well tried and proved, and in the second Mallet's mechanical process as just described. Finally, we pass to the question, To what applications has oxygen hitherto been put? As the supporter of combustion, we owe to it heat and light; and as the medium of respiration, it is the condition of life. AS AMMONIO-MAGNESIAN PHOSPHATE. By THOMAS ROBERTSON OGILVIE. ALTHOUGH this process is one of the most important and most frequently used methods in the whole field of analysis, a very considerable number of directly contradictory statements regarding the precautions to be observed in its manipulation have been published during the last few years by chemists in this country and elsewhere. For instance, several authorities state that the precipitation of the ammonio-magnesian phosphate should take place in a cold solution. Watts, in his " Dictionary," says (vol. iv., p. 543), "Care must be taken not to allow the liquid to become very hot, as in that case hydrate of magnesium will be precipitated, and will be very difficult to re-dissolve." Schumann, quite recently (f. pr. Chem. [2], vi., 416), makes a similar statement; and Brunner (Zeitschr. Anal. Chem., xi., 30-32) gives the results of two analyses of a bone-ash, showing that the one done at 60-70° C. was 1.25 per cent of P2O5 higher than the other done at 20° C. On the other hand, Parnell (CHEM. NEws, vol. xxiii., p. 145) recommends precipitation in a warm solution: he says “In order to insure the purity of the precipitate I now raise the two ammoniacal solutions to the boiling-point; on mixing them and stirring, a bright crystalline precipitate appears, which so far has never failed to be pure." Munroe also (CHEM. NEWS, vol. xxiv., p. 32) prescribes the same means as a precaution by which to get a precipitate of the greatest purity. Another matter on which differences of views exist is the influence of citric acid. In a valuable paper written by Fresenius, Bauer, and Luck (Zeit. f. Anal. Chem., vol. X., p. 133), the statement is made that magnesium citrate is often precipitated with the phosphate, while Warington, who originally proposed the adoption of citric acid instead of tartaric acid, asserts (Journal of the Chemical Society, vol. x., p. 326) that he " never obtained any precipitate by treating magnesia mixture with citric acid, though varied conditions have been tried." Again, Fresenius and others give as a process for the estimation of phosphoric acid in combination with alumina, the addition of sufficient citric acid to hold up the oxide and the precipitation of the acid as ammonio-magnesian phosphate. Well, the explicit statement is made by Knap (Zeitsch. f. Chemie, vol. ii., p. 157) that he found the presence of alumina rendered the estimation of phosphoric acid impossible by this process, as, even after allowing the solution to stand for some time, no precipitate was found. A further point of dispute is the value of re-dissolving and re-precipitating the precipitate as a means of freeing it from impurity. In the text-books this precaution is recommended and recently Kubel (Zeit. f. Anal. Chem., vol. viii., p. 125) asserted that as the weight of the pyrophosphate is invariably too high, the ammonio-magnesian phosphate should be re-dissolved and re-precipitated at least once. Heintz says (Zeit. f. Anal. Chem., vol. ix., p. 16) the error arising from the co-precipitation of magnesium hydrate or of neutral or basic magnesium sulphate can be corrected by once more re-dissolving and re-precipitating. On the other hand, Schumann (7. pr. Chem. [2], vol. vi., p. 416) considers it unnecessary to re-precipitate if the addition of a great excess of magnesia solution is avoided; while Parnell (CHEM. NEWS, vol. xxiii., p. 145) states that he sometimes found the ignited precipitate to contain an excess of magnesia to the extent of 8 per cent, and in such cases re-solution in hydrochloric acid and reprecipitation with ammonia failed to give a pure precipitate. I might go on to quote further conflicting statements regarding the other details of this process, but I think I have brought forward sufficient to w that there is great necessity for investigation as to Ge exact and specific siden |