gradually congeals into a reddish-brown resinous mass of the consistency of butter. Bromine.-Fulmination with very few gray vapours; the residue is a brownish red resin and a yellow liquid having a greenish tint, the whole being miscible to a wine yellow oil; the odour is little altered, scarcely terebinthinate. 1. bromine generates some white fumes; the oil re ns nearly unaltered in colour, while the lower liquid soon takes a purplish brown colour. Oleum Terebinthina.—Thin, colourless, free of resin. Iodine fulminates with energy, evolving violet vapours: the residue consists of undecomposed, brown-red oil, and a blackish brown iodine compound, which, after some time, is miscible to a soft dark brown mass, which in contact with the air turns greenish brown, and has a disagreeable empyreumatic terebinthinate odour. Z. Violent fulmination, with purple-coloured vapours; Very little soluble, without any visible reaction to a the oil has a brownish carmine our, turning to red pale, gradually deeper carmine-coloured liquid; other-brown; around the dark sediment some greenish coloured wise, the oil is unaltered. liquid is observed, the whole after a while readily miscible; odour terebinthinate, empyreumatic. Oleum Petra.-Colourless, very thin and mobile. Iodine. Not soluble, but gradually altering into a tough, dark yellow-brown, resin-like mass, which firmly adheres to the glass, the oil assuming a pale carmine colour, which, in contact with the air, gradually turns brown. Z. Ether sol. iodine produces some spreading of a small quantity of a carmine coloured oil, with a larger portion of a nearly black liquid; after this reaction has subsided fine spots of a brown coloured mass remain upon the sides of the vessel, a black oily sediment separates, while the supernatant transparent liquid is of a rose colour. After six hours, part of the oil has worked itself over the edges of the vessel, leaving a little of a deep carmine coloured liquid behind, and a black mass, which in very thin layers appears of a brown carmine red. Bromine.-No reaction by three drops; the bromine collects on the bottom, dissolves slightly in the oil, colouring it yellowish red, and constantly evaporating from the surface with a slight effervescent motion; six hours afterwards, the whole mixture has evaporated, leaving no residue, and the odour of the oil unaltered. Ether sol. bromine sinks to the bottom, leaving the supernatant oil scarcely tinged with yellow. Oleum Sabina.-Thin, colourless. Iodine.--The oil distilled from the leaves and the tops of the branches, showed with iodine the highest tem perature, fulminated quickly and violently, and left a reddish brown residue, of the consistence of honey, easily miscible with the undecomposed oil. Another heavier oil was after the reaction with iodine, thinner and olive green. Z. Brisk detonation, with violet and gray vapours; th residue consisted of a little greenish brown sediment and a blackish green clear liquid, which were readily miscible. Ether sol, iodine yields a light reddish yellow liquid and a heavier iodine coloured oily fluid; the two are miscible, though not very readily. Fther sol. iodine settles to the bottom without any visible reaction, the oil gradually assuring a brown carmine colour. After six hours, it has been spreading out of the watch crystal, leaving a light brown resinous mass behind, of a peculiar resinous, empyreumatic odour. Bromine causes a most violent fulmination, with an abundance of white vapours; much of the oil is thrown away, the remaining oil is colourless and unaffected. Ether sol. bromine evolves white vapours; during the reaction the whole turns white; the sediment then assumes a light yellowish colour, leaving the oil colourless; the two strata are not miscible. II. The Oxygenated Oils.-Oleum Absinthii.— Brown, thick, old. Iodine. The action of iodine varies considerably with the age of the oil or of the herb from which it has been produced. Fresh and well-kept oil is rendered of a grass green colour, with little heat, but otherwise without reaction; older oils may show a radiating motion, with iodine vapours and a tough extractive residue; or detonation, with evolution of violent vapours, and leaving a brown syrupy residue. Z. It dissolves with radiating motion to a deep brown syrupy liquid. Ether sol. iodine mixes with the oil to a dark olive brown liquid. Ether sol. bromine yields a blackish brown mixture without any reaction. Oleum Anisi-Transparent, colourless. and white vapours; by stirring, the whole hardens Iodine. The oil, moderately heated, gives off reddish quickly to a resin-like mass, which on cooling is fragile. Z. Ether sol. bromine.-The mixture turns instantly colourless with a hissing noise; a lower stratum is sepa-motion and scarcely any vapours; the particles of iodine It dissolves slowly in the cold oil with some radiating rated, which has a whitish colour, changing to dark adhere together and the residue is an iodine coloured brown, while the upper liquid, at first transparent and liquid. But if the reaction has been facilitated by quick colourless, is rendered slightly milky. and continued agitation or slight heating, the whole soon congeals to a brittle brown mass. Oleum Succini.-Thin, and nearly colourless. Iodine.-Without visible reaction, the dissolving iodine combines to a dark, thick liquid, which, after some time, mixes but imperfectly with the thinner yel lowish brown oil. Z. It is partly dissolved with little motion to a yellowish brown liquid, scarcely miscible with the thicker lower stratum. Ether sol. iodine.-Without any reaction two strata are formed, the upper one of which is thin and yellow, the lower one thicker and of iodine colour. After six hours, the greater part of it has been working itself out of the vessel, leaving a thin yellow liquid behind. Ether sol. iodine causes little spreading, is miscible to an iodine coloured liquid, and in a few minutes congeals and has turned to a deep coffee brown; in twelve hours to a butyraceous mass, which in six hours is still sticky the mass is hard and brittle. the colour is white, afterwards colourless; more bromine Ether sol. bromine produces a quick, radiating motion; alters it to a light purplish brown. Oleum Anisi Stellati.-Thin, pale yellow. Iodine generates without effervescence, some bluish red vapours and little heat; on stirring the mixture it soon hardens to a resin-like brittle mass. Z. OHEMICAL NEWS, On the Molecular Dissymmetry of Natural Organic Products. March 1, 1862. There is scarcely any difference in its behaviour to iodine from that of oleum anisi. Ether sol. iodine.-Perfect solution of iodine colour, without spreading; it thickens in a few minutes to a butyraceous mass, which after several hours is hard and brittle. Bromine.-Whizzing noise, white fumes, effervescence; the residue consists of a reddish resinous body, and a liquid of a greenish-yellow colour, which is somewhat thicker than the original oil. Ether sol. bromine.-Quick radiating motion; the oil turns white immediately, and remains of that colour; more bromine colours it yellowish red, it evaporates in two layers, the upper one of which is lighter coloured, somewhat turbid, and turns to a purplish colour. Oleum Aurantii Corticis.-Pale yellow, thin, about a year old. Iodine. The fresh oil shows brisk fulmination, less than oil of neroli. A thick, dark iodine compound is parated from the brown red liquid residue, the whole miscible to a not homogeneous fluid. Beschorner observed no heat or fulmination, but a radiating motion and brown red solution, properties which probably belong to oil distilled from the old dry peel. Z. Some radiating motion and no vapours were observed; the oil is of a reddish yellow, miscible with the iodine sediment to an iodine coloured solution. 119 Vivid raction, with heat, detonation and the evolution of purple and yellowish fumes; the residue consists of a black extract and a yellow oil, which are readily miscible to a dark, nearly unctuous liquid; the odour is acetous, aromatic. Ether sol. iodine.-Some effervescence; the homogeneal thin liquid is of a bright yellow iodine colour, gradually deepening; in six hours a dark brown pitchy mass remains behind. Bromine.-Vigorous reaction, with detonation, heat, and white fumes; the residue is reddish yellow, the supernatant liquid yellow, and both are miscible to a greenish yellow oil; the odour is little altered and free of acetosity. Ether sol. bromine.-The reaction takes place by an energetic working from the centre towards the circumference in one or two directions; the colour is greenish brown yellow, at the conclusion of the reaction reddish brown yellow; the supernatant liquid is slightly cloudy, whitish, subsequently limpid. (See also Oleum limonis.) Oleum Cajeputi.-Thin, pale yellowish green. Iodine dissolves slowly in the crude oil without visible reaction, the residue appears curdled. Another sample showed radiating motion, with few reddish fumes and little heat, and a more coherent residue. The rectified oil evolves yellowish red vapours, little heat, and leaves as residue a greenish brown curd, by agitation adhering to a crumbling mass, which appears to be characteristic liquids, the upper one pale yellowish, the lower one thick, reddish for this oil. Z. brown, almost black; in six hours the whole was altered • Ether sol. iodine.-Spreading; forms tw into a dark pitchy mass of an acidulous odour. Bromine. The reaction is so violent that most of the oil is thrown out of the vessel, and many white fumes are given off, with the evolution of much heat; the oil left behind assumes a brownish colour, Ether sol. bromine generates some white vapours; the oil is at first left uncoloured, while a brisk reaction is going on; it then assumes a bright yellow colour, in a short time yellowish brown stripes appear, forming into a slowly-rotating crescent, which leaves a brown colour behind; the rotation ceases as soon as the colour has become a uniform deep brown; the supernatant oil is, now of a pale brown colour and perfectly transparent. The rotating crescent appears to be a characteristic reaction of oil of orange-peel, with ethereal solution of bromine, and appeared in all the repetitions of this experiment. I have tried to find out how far it is influenced by the presence of other si ils, and will here state the results. Oil of bergamot four parts, oil of orange one part.— The ethereal solution of bromine has but little radiating motion; a smal crescent appears and disappears alternately; after the reaction, the colour is of a deep reddish brown, the supernatant fluid is whitish, turbid, after wards clear. Oil of lemon four parts, oil of orange one part. Around the ethereal solution of bromine in the centre of the oil, a brisk reaction takes place, and a bright yellow colour is produced, in which soon a small crescent is formed, running together to a brown spot; the whole sedimentary liquid assumes a yellowish brown colour; the supernatant is milky and brownish white. Oleum Bergami.-Thin, greenish yellow. Iodine.-Brisk fulmination with effervescence, violet and yellow-red vapours and much heat, more than oil of orange. The homogeneous residue is of a yellowish brown colour, an extractive consistence, and of an acidulous balsamic odour. Z. the oil has an iodine colour, and the sediment by agita It produced a radiating movement, without vapours; tion runs together into a crummy resinous mass. Ether sol. iodine.-Spreading, mixing to an iodine coloured liquid; after six hours the liquid had partly overrun the edges of the vessel, leaving a crummy mass, of a nearly crystalline appearance, together with very little fluid of a yellow iodine colour. Ether sol. bromine sinks to the bottom; the supernatant liquid is scarcely coloured; the reaction is-manifested by the appearance of minute greenish, and blackish green drops; they are with difficulty miscible by stirring, but separate again as a more homogeneous heavy liquid. (To be continued.) PHYSICAL SCIENCE On the Molecular Dissymmetry of Natural Organic (Continued from page 109.) HEMIHEDRITY1 is assuredly, among the peculiarities of crystallisation, the one which is the easiest to seize in it external manifestation: consider, for example, a species of mineral crystallising in the cubic form. This form, as all know, may surround different kinds of determinate forms by the law of symmetry, a law so natural that it is, that a form being given, all others compatible with it may be obtained by a contrivance which would consist in modifying, truncating, as Romé de Lisle said, at the same time and in the same manner, the identical parts. The identical edges are those which are at the intersection of faces respectively identical angles, those which are formed by dihedral angles respectively, equal and similarly placed. For example, in the cube there is but one kind of solid angle and one kind of edges. Let one of the solid angles be truncated by a face equally inclined 1 Émisus, half; edron, side. to the three faces of the solid angle, and the seven other angles should be, at the same time, by a face of the same nature. This is observed in alum, in galena, and generally in all cubic species. Let us consider a right prism with a rhomb base. The eight edges of the bases are identical If one is truncated, the seven others should be, and in the same manner. The four vertical edges are of another kind. Generally, they will not be truncated at the same time as those of the bases, and if they are, it will be differently. These examples alone will suffice to explain the law of symmetry and its application. NUTS it exists; there it is absent. Upon the same crystal there are angles which bear the face ; others, which should have it, have it not. Sometimes we find plagihedral faces to the right and to the left. Nevertheless, all persons versed in a knowledge of crystals, admit that there is in quartz a true hemihedrity in two opposite directions. Here is placed a very ingenious approximation, due to Sir John Herschel, communicated to the Royal Society of London in 1820. M. Biot, as I previously said, made the remarkable observation, that among the specimens of quartz, some deviated in the direction to the right and to the left. This stated, Sir John Herschel associated the crystallographic observations of Hauy with the physical remark due to M. Biot. Experiment confirmed the idea of a relation, in fact, between the right and left plagihedrals and the right and left optical deviations. Specimens of quartz which bear in one direction the face x, deviate the plane of polarised light in the same direction. Such is an exposition of the principal facts which have preceded the researches, an abridged history of which I have to relate. (To be continued.) PROCEEDINGS OF SOCIETIES. Nothing is more simple than to have a clear idea of hemihedrity. Experiment has long since shown Haüy was acquainted with the most celebrated instances, that in a crystal the half only of the identical parts are sometimes modified at the same time and in the same manner. It is said in such case that there is hemi hedrity. Thus, the cube ought to be truncated at the same time on its eight solid angles. But, in certain cases, it is so only on four. Boracite affords an instance of this kind. Under these circumstances, the modification occurs in such wise that in prolonging the four truncations in a way to make the faces of the cube disappear, we obtain a regular tetrahedron. If the modification were applied to the four remaining angles it would produce another regular tetrahedron, identical with and superposable on the first, and differing from it only by its position on the cube. In the same way, let us take our right prism truncated on the eight edges of its bases. In certain species the truncation occurs upon half of the edges only, and it also happens here that the truncations, bearing upon edges opposite at each base and crossing at the two extremities, when prolonged lead THE third paper read by Mr. J. ATTFIELD was entitled to a tetrahedron. There are two tetrahedrons possible, as "Poisons not always Poisons." In his microscopic for the cube differently placed in relation to the prism, examinations of the saline efflorescences mentioned in the accordingly as it preserves such or such group of four preceding paper, Mr. Attfield discovered that some of the truncations; but here the two tetrahedrons are not abso- most active extracts in the Pharmacopoeia-extract of lutely identical. These are symmetrical tetrahedrons. colocynth and extract of nux vomica, for example-supWe cannot superpose them. ported colonies of lively little animals, greatly resembling These notions suffice to show what is meant by hemi-cheese-mites. They proved, in fact, to be a hitherto hedrity and what is understood by hemihedric faces or forms. Now, quartz, of which we just spoke, is one of the rare mineral substances in which Hauy found hemihedric faces. The habitual form of this mineral, a regular hexagonal prism, terminated by two pyramids of six faces, is well known. It is clear that the trihedral angles, situated at the base of the faces of the pyramid, are identical, and, consequently, if one of them bears a face, it ought to be reproduced on all the others. This is true of the face termed rhombiferous by mineralogists. But Haüy first remarked in certain specimens, a face very different from this, which he designated by the letter x, which falls more on one side than on the other, without being double, as the law of symmetry would in this case require. Another very curious peculiarity of these crystals has not escaped crystallographers. It is, that the face x is inclined sometimes in one direction and sometimes in another. Haüy, who was fond of bestowing epithets appropriate to each variety of a species, applied the term plagihedral to the variety of quartz having the face x. Crystals in which the face x inclined to the right are designated under the name right plagihedrals, the crystal being adjusted in a suitable manner; and those crystals in which the face x inclined in an opposite direction are termed left plagihedrals. Nothing is more variable than this character. Here PHARMACEUTICAL SOCIETY. Mr. P. SQUIRE, President, in the Chair. (Continued from page 110.) unknown species of acari. Other irritating substances have been known to support similar animals. Ginger has been found to be infested with them; but in this and similar cases it was supposed that they lived on the starchy matter and rejected the active principle. But it was impossible that they could eat extract of nux vomica strychnia was not assimilated. Mr. Attfield, therefore, colwithout eating strychnia. It might be, however, that the lected some acarine excrement (the excrement floats on, while extract of nux vomica sinks in water), tested it for strychnia, and only discovered a faint trace of that body, which he believed to have been dissolved off the extract Some of by the moist excrement. But, to prove that these animals fact of an animal becoming habituated to a poison is not new. Men eat arsenic, opium, and tobacco, until their daily dose is sufficient to kill from two to ten of their species. Sheep have been known to eat poisonous plants until their mutton produced serious effects on those who ate it. Hedgehogs will eat anything, and toads are indif ferent to prussic acid. Drawings of three acari discovered were exhibited, and Mr. Attfield said that Mr. Busk had decided that those found on the extracts of colocynth and taraxacum belonged to the same genus, but were of different species, and that those existing on nux vomica were generically different to the others. Mr. DEANE noticed that the acari figured greatly resembled some found a few years ago under very peculiar circumstances. At a village near Colchester, the name of which we did not catch, a church was rebuilt, the floor being lowered to within a few inches of some coffins that had lain underground for two or three centuries. Soon after the new church was opened the pews were found to be infested with acari, so numerous in some places as nearly to hide the fittings. It turned out to be a new species of acarus, and received the name of the Acarus ecclesiasticus. The parishioners were greatly alarmed at the visitation, and regarded it as a judgment of the Almighty for desecrating the graves of their forefathers. Mr. Deane added that the animal was very like that made by galvanism, some years ago, by the late Mr. Cross.1 The CHAIRMAN, in a neat speech, expressed the thanks of the meeting to Mr. Attfield for his liberal contribution of papers. The time for adjournment having arrived, Professor BENTLEY's paper " On Podophyllin" was taken as read. CHEMICAL SOCIETY. Thursday, February 20, 1862. He Dr. A. W. HOFMANN, F.R.S., President, in the Chair. Dr. MATTHIESON read a note on Professor Bolley's paper "On Alloys of Lead and Tin." He first referred to a table of the specific gravitjes of various alloys of lead and tin, drawn up by Professor Bolley, which had been published in the Journal of the Chemical Society. considered that a mistake had been made in the method adopted of calculating the theoretical specific gravities for the purpose of ascertaining which alloy underwent the greatest expansion during its formation; the theoretical specific gravity having been deduced from the comparative weights of the metals contained in each alloy, instead of from the volumes, which accounted for the discrepancies between the calculated and the real specific gravities. In a paper that had been published in the Philosophical Magazine, Dr. Matthieson had pointed out that the gravity ought to be calculated from the volumes of the constituent metals. As an example, he took the case of an alloy of equal parts by weighing of platinum and aluminium, which according to Professor Bolley's method of calculation, would have a specific gravity 11.97; the real gravity being 4:46, which would also be the result arrived at by calculating from the volumes employed; for, taking the specific gravity of aluminium at 2.5, and that of platinum at 21:45, one gramme of aluminium would displace 04 grammes of water; one gramme of platinum would displace o'047 grammes of water. Therefore, by dividing the weight of metal in the alloy by the weight of water displaced, the specific gravity would be obtained; but 2÷0447=4'46=the specific gravity, found by experiment. It further appeared that the alloy in which the greatest expansion took place, was that containing the two equiva 121 The next Paper was by Mr. G. GORE, "On the Quantitative Determination of Alkalies in Fire Clays and other insoluble Silicates." The ordinary process of decomposing fire-clays, &c., for the determination of alkalies by means of hydrofluoric acid being very tedious, and the method of heating with nitrate of baryta, not altogether satisfactory on account of the difficulty of ensuring a perfect decomposition, the mixture being only agglutinated by heat and not perfectly fused, a rather different process was proposed. An intimate mixture of the finely powdered fire-clay, nitrate of baryta, and fluoride of barium, was to be projected into a heated crucible; when all the mixture had been thrown in, the crucible was to be covered and gradually heated in a furnace until the contents were completely melted; the mixture was then to be poured into a cast iron vessel and immediately covered over. The resulting fused mass finely powdered, digested with suiphuric acid, evaporated to dryness, and afterwards treated in the usual manner. The results of the analyses made in this manner agreed with those obtained by the hydrofluoric acid process. The next Paper was by Professor KOLBE, "On the Constitution and Artificial Formation of Taurin." From a consideration of the relation existing between propionic acid, alanine, and lactic acid on the one hand, and ethyl sulphuric acid, taurin, and isethionic acid on the other, the formulæ of these substances being as follows Propionic acid HỌ, CH[C,O,]O. [CH] [H2N it was inferred that taurin was similarly constituted to alanine. It had been pointed out some years ago by Strecker, that taurin might be obtained from isethionate of ammonia, and when treated with nitrous acid it again furnished isethionic acid. The action of caustic potash on taurin proved that it was not an amidogen compound, for no ammonia was formed on boiling with this reagent. It might be objected to this view, that taurin does not form saline compounds with alkalies or acids, but against this it was to be remembered that amidogen introduced into a compound weakened its acid properties, and that although definite compounds could not be prepared, still taurin showed a tendency to combine with bases, as would appear from the following properties of taurin prepared from ox bile. Taurin may be dissolved in acids and crystallized from thee solutions unaltered, it does not combine with salts nor does the hydrochloric acid solution furnish a platinum salt. It shows some tendency, however, to unite with bases, for a saturated aqueous solution is not precipitated by alcoholic ammonia, although alcohol alone precipitates it. Caustic potash has a similar power of preventing the precipitation by alcohol, but carbonic acid passed into the solution causes a precipitate; a compound with oxide of lead may also be formed, which is decomposed by carbonic acid. From these properties it would appear that, although incapable of forming definite saline compounds, taurin possesses feeble acid properties. It seemed probable that if isethionic acid had a constitution similar to lactic acid, it would, when acted on by pentachloride of phosphorus, yield chloride of chlorethyl-sulphuric acid; on trial this proved to be the case, the reaction being analogous to that with lactic acid, the body produced lents of lead and one of tin, and not that containing single having the composition C. [] (8,0,)Cl. This substance equivalents of the metals, as stated by Professor Bolley. 1 Or, rather (according to Dr. Warwick), obtained by Mr. Cross from old glove-boxes.-ED. CHEM. NEWS. on being heated with water, was decomposed, hydrochloric and chlorethyl-sulphuric acids being formed; some diffi acid; the oxydation took place more readily if the ethyl compounds of the acids were employed. culty, however, was experienced in the purification of the chloride on account of the simultaneous formation of a body having nearly the same boiling point, which appeared to be the chloride of isethionic acid; a solution of chlorethyl-sulphuric acid might be boiled without decomposi-a tion, but on heating its salts with alkali decomposition took place; the chlorine in this substance might be replaced by hydrogen by means of an amalgam of sodium. Taurin might be obtained either from the chloride or from the silver salt of this acid, by the action of ammonia, but in the latter case it was contaminated with a substance which gave off ammonia when boiled with potash. The properties of the taurin obtained in this manner agreed with those of the taurin from ox bile. Professor Kolbe was of opinion that many similarly constituted organic compounds might be prepared artificially. Dr. ODLING did not agree with this view of the constitution of taurin, for the relation between isethionic acid, taurin, and chlorethyl-sulphuric acid was the same as that existing between hydrochloric acid, water, and ammonia; and there was no ground for concluding that, because a similar series was found to exist both in the isethionic acid and the propionic acid group, these bodies were similarly constituted, for in almost every group the same series of chlorides, hydrates, and amide existed; it seemed, however, that a difference between isethionic and sulphovinic acid had been established, for the isethionic acid formed a chloride, which passed through two successive steps of decomposition, tending to show that it was a bibasic acid. A Paper, by Mr. W. VALENTINE," On a New Source of Acetone," was then read by the Secretary. An examination of the inflammable liquid formed during the preparation of aniline, proved that it consisted chiefly of acetone, together with benzole and its homologue Mr. PERKIN remarked that had found very small quantities of acetone in the aniline residues. ues, Mr. CHURCH said that two years ago he had seen some acetone in Mr. Williams's laboratory, which had been obtained from the same source. The next Paper was by Dr. PHIPSON "On Some Transformations of Citric, Butyric, and Valeric Acids." From a consideration of the change that malic acid undergoes when fermented, yielding first succinic and afterwards butyric acid, he had concluded that citric acid might undergo a similar transformation. To ascertain this, a mixture of citrate of lime and casein was allowed to ferment; but under these circumstances only butyric acid was formed. It then occurred to him that a different ferment might answer better, so a mixture of citrate of soda, carbonate of soda, and putrid beef was prepared; in which after some time a volatile and odorous substance was formed together with butyric acid, which appeared to be succinic acid; under certain circumstances, the butyric acid was formed without an evolution of hydrogen. Boiled beef and citrate of lime also gave traces of succinic acid. He next endeavoured to obtain succinic acid by oxydation, permanganate of potassa being employed as an oxydizing agent; with citric acid only oxalic acid was obtained, but butyric acid yielded succinic acid, acetic acid being formed at the same time, and consequently butyro-acetic acid. M. Dessaignes had already shown that succinic acid might be obtained from butyric acid by the action of nitric acid; valerianic acid also furnished acetic and succinic acids when acted on by permanganate, and suberic acid was perhaps produced at the same time. The method of conducting the experiment was as follows:-Permanganate of potash and nitric acid were added to the acid to be oxydized, and the whole heated until a reaction set in; after this had subsided, the solution was boiled, a long tube being fixed to the neck of the flask containing the mixture, to condense the vapour arising; if at the end of the operation any permanganate was left, this was decomposed by means of a little zinc before testing for succinic Professor F. FIELD then read a Paper, "On the Double Sulphides of Iron and Copper." He had previously made communication to the Society on this subject, in which he had alluded to a method of treating copper ores which was adopted in countries where fire-clay was expensive, the ordinary method of roasting the copper pyrites being very hurtful to the furnace, on account of the oxide of iron forthing a slag with the clay of the furnace. The method consisted simply in adding carbonate of copper to the regulus, by which the oxydation of the ore was hastened; this plan, however, was very rarely adopted. From the analyses that he had made of the double sulphide of iron and copper, he had come to the conclusion that this ore always contained the copper in the state of disulphide, and that on roasting, all the iron was oxydised before the disulphide of copper was touched. It had been observed that as the percentage of copper increased, the ore became less easily acted on by acid, and therefore that the iron had a different degree of sulphuration, in the latter case, but he considered that this fact alone did not establish this difference, for that the smaller per centage of the iron was sufficient to account for the difficulty with which it was acted on,-a similar effect being produced when a small quantity of silver is alloyed with a large quantity of gold, the gold protecting the silver from the action of nitric acid, which, under ordinary circumstances, attacks it readily. From his experiments, it appeared that the successive stages of decomposition were as follows, the original regulus having the following composition:3(Cu, S), Fe, S,, FeS, 2Fe,S; after roasting for some time the only change was an increase in the amount of sulphide of copper, the composition being represented by the formula 6(Cu2S) Fe, S, FeS, 2Fe, S; on longer roasting a still further increase in the amount of sulphide of copper took place, the compound containing twelve equivalents of sulphide of copper, the remaining iron being combined with sulphur as before. With the blue sulphide similar results were obtained, and a table had been draw up exhibiting the various stages of decomposition. MANCHESTER LITERARY AND PHILOSOPHICAL SOCIETY. Ordinary Meeting, February 4, 1862. J. P. JOULE, L.L.D., F.R.S., President, in the Chair. Mr. BINNEY said that soon after the death of Professor Eaton Hodgkinson, F.R.S., one of the former Presidents of the Society, and a man of science, of whom not only, this Society, but the city of Manchester, has good reason to be proud, a few of his friends and admirers gave a commission to Mr. Slater, the sculptor of London, to execute a bust of the deceased, to be presented to this Society. As his valuable memoirs which gave to the world the formulæ for solid and hollow pillars of cast iron, now the basis of calculation on all structures of that metal, were printed in our Transactions, it was thought that the Hall of the Literary and Philosophical Society of Manchester was the fittest place for the bust of their discoverer. The following gentlemen, viz., our worthy President, J. P. Joule, LL.D., F.R.S., E. Schunk, F.R.S., James Heywood, F.R.S., John Hawkshaw, C.E., F.R.S., Joseph Whitworth, F.R.S., R. P. Greg, F.G.S., Thomas Turner, F.R.C.S., G. R. Stephenson, C.E, Robert Rawson, and E. W. Binney, F.R.S., present the bust to the Society. On the motion of Mr. SPENCE, seconded by Dr. R. ANGUS SMITH, it was resolved unanimously :-"That the thanks of the Society be given to the donors of the bust of the late Professor Eaton Hodgkinson, F.R.S." |