NEWS almost an opposite fashion,--namely, iron. Considered 36 more frequently spoken of by chemists under the neutral appellation of pyrogalline. At present, the solution in the dish, though exposed freely to the air for upwards of an hour, has not undergone any appreciable oxidation. I now moisten the interior of this long tube with a little aqueous potash, and insert it in the solution, when the commencing oxidation of the dissolved pyrogalline is manifested to you by its almost immediate assumption of a brown-black colour, followed by the gradual rising up of the black liquid in the tube, through its partial absorption of the oxygen of the contained air. The pyrogalline, which did not become oxidised in any appreciable degree so long as there was no alkali present, now becomes oxidised with considerable rapidity, as you observe, yielding among other products acetate, oxalate, and carbonate of potassium. A familiar illustration of this action of alkalies is afforded us in the employment of lime to promote the destructive oxidation of dead bodies, and as a manure to destroy the organic matter of peaty soils. Some very interesting results have also been obtained by Gorup-Besanez, who found that glycerine, sugar, leucine, hippuric acid, oxalic acid, and the fatty and aromatic acids, which of themselves were unacted upon by ozonised air, underwent a very complete oxidation when submitted to the same reagent in the presence of caustic or even carbonated alkali. Benzoic acid, for instance, which results from the violent oxidation of animal matter, and consistently resists the action of powerful oxygenants, undergoes a complete and somewhat speedy oxidation when submitted in alkaline solution to the action of ozone. And in some of these oxidations the curious circumstance was noted, that between the original substance, stearic acid C18H3O2, or benzoic acid C-H6O2, for A few words upon the effect of alkalies in promoting instance, and the final carbonic acid, no intermediate prooxidation. I mentioned in my last lecture the peculiar ducts could be detected. It seemed, indeed, as if portion after decomposition of animal substances resulting from their portion of the original substance was completely oxidised and treatment with caustic alkali, and consisting in an oxida- broken up into separate molecules of carbonic acid, instead tion of their carbonous at the expense of their hydrogenous of the entire substance undergoing a gradual oxidation and constituents. Now, this action is apparently determined simplification, by the successive burning off of its constiby the tendency that exists among differently characterised tuent carbon atoms into carbonic acid. With such facts elements to arrange themselves in stable groupings, and as these before us, I would suggest that the so-called remore particularly to form stable oxi-salts. The presence solvent action of alkalies upon the animal economy, like of alkali rendering the formation of such salts possible, that of iodine, is a direct consequence of the peculiar cheby furnishing the necessary base, we find that under treat-mical characterisation by which they are enabled to act as ment with caustic potash KHO, for instance, the carbon oxidising agents. of organic matter is oxidised into various acids which appear in the form of their respective potassium salts, while the excessive hydrogen of the organic matter, together with that of the potash employed, is liberated in the gaseous state, as exemplified by the reaction of caustic potash upon oil of bitter almonds, already more than once referred to. As a result of this tendency, then, we obtain, as I have previously remarked, very similar products by fusing animal substances with caustic alkalies, and by submitting them to the action of powerful oxygenants. It is observable, however, as well in artificial as in natural processes, that the ultimate effects of a gentle chemical action are often more complete than the immediate results of a comparatively violent one; and it is to this more gentle action of alkalies that I would now direct your attention. We find that many organic substances, which of themselves are scarcely affected by exposure to oxygen or air, undergo a complete and even somewhat rapid oxidation under the influence of alkalies, the tendency of their constituent carbon to become oxidised, otherwise inferior to that of their constituent hydrogen, becoming intensified, apparently because of the opportunity afforded by the presence of the alkali for the formation of salts instead of acids. Be the explanation, however, what it may, the fact is unquestionable, and readily admits of experimental illustration. For instance, I have in this porcelain dish the watery solution of a substance well known to photographers as pyrogallic acid, though its acidity is of such a feeble character that it is nowadays Despite, however, the interest of these questions, upon which I have been able to bestow but a very hasty notice, I must now break off their discussion altogether, and regretfully take my leave of you. In bringing this course of lectures to a conclusion, I have to thank you all, and more particularly the President and Fellows of the College, for the kind encouragement which your continued presence has afforded me. I am aware how far short these lectures have fallen of that degree of excellence which I had hoped to attain, and you had a right to expect; and how much the measure of success which has attended them must be attributed to the intrinsic interest of the subject, and your good-natured willingness to be pleased with its expounder. I have endeavoured throughout to bring prominently before you the dynamical idea of organic chemistry, as connected with changes of composition. I have shown you that, in the organism of the plant, carbonic acid and water are submitted to a constant deoxidising change, whereby they become successively converted into more and more complex bodies, many of which we are now able to produce, all of which we hope some day to produce, by similar processes in the laboratory; that the change in composition undergone by carbonic acid and water is attended by a storing-up of force in the resulting products, and that the correlative change in composition undergone by these products into water and carbonic acid is attended by a liberation of their stored-up force; that in every organ of the animal body oxidation is continually taking place to supply that organ with the force necessary both for its nutritive acts and external manifestations; that the juice of every gland and muscle is crowded with oxidised products of its own metamorphosis, similar to, or even identical with, those procurable by an artificial oxidation of its own tissue out of the body; that inasmuch as the exercise of every function of the living body is attended by, and consequent upon, a change of chemical composition, the consideration of every action of the body, even of the most mechanical action, becomes to a very considerable extent a chemical question; that while perversions of nutrition, perversions of metamorphosis, and the modifying influence of remedies, are many-sided subjects that may be viewed from many different aspects, he must have but a very imperfect and one-sided view of them, who leaves the chemical aspect altogether out of his consideration. ACADEMY OF SCIENCES. October 30. M. DE CIZANCOURT presented a memoir "On the Transformations which the Allotropic Conditions of Iron undergo | in Metallurgical Operations." All these transformations were indicated in the memoir we recently published, and we shall reserve further notice until the author publishes the practical application of his views, which he promises to do immediately. M. Fouqué has recently examined the "Gases Escaping from Sources around Vesuvius." We may say in a few words that these gases are mixtures of carbonic acid, oxygen, and nitrogen, with very small proportions of marsh and olefiant gases, and no free hydrogen. The author says, "All contain bicarburetted hydrogen, and not one free hydrogen. In Sicily just the reverse was the fact. The more distant the place of disengagement was from Vesuvius the more carburetted hydrogen they contained. And lastly, the gas from Torre del Greco, which contained free hydrogen in 1862, now contains none, but in place of it a small quantity of bicarburetted hydrogen." From which M. Fouqué concludes that the presence of free hydrogen points to a period of greater volcanic activity than protocarburetted hydrogen, and this again to more activity than bicarburetted hydrogen. M. St. Claire Deville added that M. Fouqué's researches seemed to show that the great eruption of Etna coincided with diminished activity in Vesuvius and the group of volcanic islands between them, and confirmed the opinion that there existed some connexion between all these volcanoes. MM. C. Michaelson and E. Lippman presented a note "On the Action of Monobromacetic Acid on Aniline." The authors have found that this action gives rise to the formation of two bodies, hydrobromate of aniline and phenylglycocolle. M. Sell presented a note " On a Product of the Oxidation of Erythrite." The author effected the oxidation directly by the aid of platinum black, and produced a new acid, CH, Η *H} o+O, = H_O+CH }o. MM. De Luca and Ubaldini communicated some "Chemical Researches on the Australian Myrtle (Eugenia Australis)." The shrub, it seems, grows well in the Botanic Garden at Naples, and the authors have been able to examine the juice of the fruit, which, it appears, may be compared with that of the red grape. It produces a very good wine, exactly resembling ed grape wine. Dr. Phipson communicated a note "On Zirconium," which will be found at page 171 of our present volume. Numerous communications are still addressed to the Academy every week on the all-important subject of the Prevention and Cure of Cholera. With most of these we NEWS can have nothing to do, but some have a strictly chemical bearing. For example, at the last sitting M. Elie de Beaumont read a letter from the Inspector-General of Mines in Spain, who points out that at the copper mines of Rio Tinto, in Andalusia (about which some 2000 people reside, and near which, at Seville, for instance, cholera and other epidemics has often raged), cholera has never broken out. The large amount of sulphurous acid disengaged in the process of roasting the ores is supposed to be the protecting agent. At a village two leagues distant, to which cholera had been brought from Seville, the inhabitants had asked for some loads of copper ore to roast in a public place to put an end to the epidemic. M. Fremy subsequently added that a large amount of arsenious acid was disengaged as well as sulphurous acid, and the former agent, used with so much success for several diseases, might also be a preservative. [We should be glad to have the experience of medical men at Swansea and St. Helens on this subject.] M. Lisle, the Physician to a lunatic asylum at Marseilles, sent an account of his experience on the treatment of cholera with sulphate of copper according to the plan of Dr. Burq, recently noticed by us. It seems to have been highly successful, only five deaths occurring in twenty-six cases. It is noticed also that in most cases the period of convalescence was short. To those interested we may also commend the short address of M. Velpeau, though it is calculated rather to amuse than instruct the reader, especially his story of a country doctor who came up to Paris with a specific for cholera-viz., belladonna, which was freely tried in the Paris Hospitals, but signally failed to do good, and its use was consequently given up; so the Physician went back to his home disgusted with Parisian cholera patients and Parisian doctors. NOTICES OF BOOKS. Saint Bartholomew's Hospital Reports. Edited by Dr. EDWARDS and Mr. CAllender. Vol. I. London : Longmans and Co. 1865. Clinical Lectures and Reports. By the Medical and Surgical Staff of the London Hospital. Vol. II. London: Churchill and Sons. 1865. THE two papers by Dr. Letheby in the Reports of the London Hospital Medical and Surgical Staff are-"On Liquid Diffusion in Relation to Physiology and Toxicology," and "On the Poisonous Properties of Essence of Mirbane or Artificial Oil of Bitter Almonds" (Nitrobenzole). We cannot here do more than refer our readers to the important remarks of Dr. Letheby on dialysis in relation to physiology, and must confine ourselves to an account of the author's own experiments as to the value of dialysis in toxicological investigations. It will be remembered that Mr. Graham, in his first communication on the subject, pointed out the applicability of the process in the discovery of poison in the fluids and tissues of the body, and detailed some experiments which proved that in the case of arsenious acid the greater part passed from a solution containing organic matters into the diffusate in the course of twenty-four hours. It is the quantitative results of the process to which Dr. Letheby has mainly directed his attention, and we now extract the conclusions at which the author has arrived. After quoting Mr. Graham's results, he proceeds :-"I have noticed, however, that a notable proportion of organic matter invariably passes out with the arsenic, some of which is coagulated by heat and acids, and is, therefore, albuminous, while a portion of it still remaining in solution after the action of the heat is thrown down with the ersulphide of arsenic, when the diffusate is treated with sulphuretted hydrogen; and unless the sulphide of arsenic is purified by treatment with ammonia, or by some other NEWS process, a false result as to quantity is obtained. In illustration of this, and of some other points of interest, the following experiments are cited:-These experiments were made with two sets of dialysers of different diameters, each set being composed of a dialyser with a parchment paper septum, and another with bladder. One set was 43 inches in diameter, with a superficial area of 14'5 square inches, and the other set was 3.5 inches in diameter, with an area of 9.6 inches. The liquid dialysed was two fluid ounces of thick soup made with meat, bread, and potatoes, in which one grain of arsenious acid was dissolved, and the dialyser was floated in a vessel containing twelve fluid ounces of water. The diffusion was continued for two days, and then the water was changed every twenty-four hours. Dialysis of Soup containing One Grain of Arsenious Acid. Total grs. 0'56 0'9 0'72 0.64 0'2 0'16 0'2 0:16 0°08 0'2 0°16 0.0 0'00 0'32 0'5 0'40 0.2 0.16 0.08 0'3 0'24 0'4 032 2:4 1'92 2.8 2:24 19 1:52 1'7 1.36 "It is evident, therefore, that much organic matter had diffused out with the arsenic, and had gone down with the tersulphide when the liquid was treated with sulphuretted hydrogen. It is evident, also, that the great bulk of arsenic diffuses out in the first forty-eight hours." The same things happen when a solution of tartar emetic is submitted to dialysation. We again quote Dr. Letheby's experiments : Dialysis of Soup containing 5'6 Grains of Tartar Emetic. "So that the quantity of impure tartar emetic obtained with the bladder dialyser was nearly six times as great as the quantity used." With some special precautions, the process of dialysis is applicable to the separation of all metallic poisons; but in all those cases where the poison forms an insoluble compound with the albumen or fibrine of the food or tissues of the body, or with the saline constituents of the food and secretions, it is necessary to render it soluble. This is the case with the salts of lead, zinc, mercury, copper, &c.; and in those cases the compound must be dissolved by boiling it in water strongly acidulated with hydrochloric acid." Nor is dialysis of less use in the detection of organic poisons. "The salts of the organic alkalies dialyse with the greatest facility; so that when a suspected substance is acidulated with acetic or muriatic acid, and dialysed for twenty-four hours, the salt of the alkaloid is found in the diffusate in a condition for analysis. The diffusate should be carefully evaporated to dryness, or nearly to dryness, and the residue treated with carbonate of soda, and then with alcohol, ether, chloroform, and acetic ether to separate the alkaloid from the saline and other matters with which it is mixed. In this way a very small proportion of strychnine and brucia may be discovered; and M. Grandeau has separated digitaline and morphia from the contents of the stomach. "In conclusion, therefore, it may be said that although the process of dialysis is not well suited for determining the quantity of any poison present, yet it furnishes a very easy and reliable means of discovering the fact of its presence. It is, in fact, a remarkably simple and trustworthy process for effecting a qualitative examination of suspected matters; and, above all, it enables the operator to pursue his inquiries without the risk of having his results vitiated or rendered doubtful by the use of reagents of questionable purity. Looking, also, at the facility by which the process is effected by an animal membrane, it is easy to perceive in how many ways it may be readily applied. In a case of suspected poisoning, for example, it is only necessary to place the contents of the stomach in a clean pint basin, and to tie it securely over with a piece of well-soaked bullock's bladder, and to float it, bladder downwards, in another vessel containing six or eight times their bulk of water, and to allow it to dialyse for forty-eight hours, when, in a majority of cases, the poison will be separated in such a condition as to be easily recognised. The value of the process in medico-legal researches is manifestly great; but how far the elaborate investigations of Mr. Graham may go towards the solution of physiological problems can hardly yet be determined, notwithstanding that their applications to the subject are strikingly obvious." The practical suggestion contained in this last paragraph is worthy of being followed in all cases before proceeding to other methods; but it must never be concluded that no poison is present in the contents if none should be found in the diffusate. Perhaps it would be as well in every case to acidulate the contents with acetic acid before tying them down in the basin. Want of space compels us to leave the paper on the poisonous properties of nitro-benzole for another notice. Des Odeurs, des Perfums et des Cosmetiques, Histoire Naturelle, Composition Chimique, Preparation, Recettes, &c., &c. Par S. PIESSE. Edition Française. Par O. REVEIL. Paris: J. B. Baillière et Fils. 1865. THIS is a French translation of the well-known work by Dr. Septimus Piesse, with additions by the French editor. These additions, we may say shortly, add considerably to the value of the book, giving, as they do, later information on some chemical points, and comprising some French receipts which look useful. Either this or the original will be found extremely useful as well as pleasant reading by druggists and perfumers. The Ophthalmic Review. No. 7. October, 1865. We need only notice the regular appearance of this excellent journal, with the usual selection of valuable and interesting papers. NOTICES OF PATENTS. GRANTS OF PROVISIONAL PROTECTION FOR 2322. W. Hewitt, Pimlico, "An improved composition for preventing incrustation in steam boilers."--Petition recorded September 11, 1865. 2653. W. J. C. MacMillan, J. Mason, and J. V. Scar borough, Sunderland, "A certain composition having anti-corrosive and anti-fouling properties for the preservation of and keeping clean the bottoms of iron vessels, and also for the preservation of iron submerged and iron structures exposed to the action of the atmosphere or water." 2657. J. C. Ridley, Newcastle-on-Tyne, "Improvements in apparatus for applying carbonic and other gases to iron and other metals in a molten state."-October 14, 1865. 2694 T. King, Park Road, Holloway, " "Improvements in the manufacture of chemical toys, known as Pharaoh's serpents.'"-October 18, 1865. 2701. W. Clark, Chancery Lane, "Improvements in printing or impressing and dyeing fabrics and tissues." A communication from F. Déhan, Boulevart St. Martin, Paris.--October 19, 1865. NOTICES TO PROCEED. 1790. A. V. Newton, Chancery Lane, "Certain improvements in the manufacture of superphosphate of lime from guano." A communication from G. A. Liebig, Baltimore, Ma., U.S.A.-Petition recorded July 6, 1865. 2448. W. Unwin, Sheffield, "Improvements in the manufacture of iron."-September 25, 1865. 2559. W. H. Phillips, Nunhead, Surrey, "Improvements in apparatus and means for extinguishing fires, part of such improvements being applicable to other purposes."-October 5, 1865. 2648. J. De Witt Brinckerhoff, New York, U.S.A., "An improvement in preparing paper and the surfaces of other materials for use in photography.”—October 13, 1865. CORRESPONDENCE. How Things are Done at South Kensington. To the Editor of the CHEMICAL NEWS. SIR,-In your impression of Friday last you gave the names of the candidates who at the last May examination obtained Exhibitions to the Royal School of Mines, &c. As I have reason to believe there is a great deal of "redtapeism" and considerable mismanagement in connection with the South Kensington Examinations in Science and Art, I shall feel obliged if you will make the following facts public:: There being no examination held in Sheffield, I, in May last, went to the inconvenience and expense of remaining more than three weeks in London, for the express purpose of passing the examinations and obtaining an exhibition to the Royal School of Mines. I received notice of my success in the different subjects towards the end of June and beginning of July, and heard nothing more in reply to my inquiries until after the commencement of the session, which began on October 2. Then came the list announcing the medals I had obtained, but still no word of my success or failure. As the lectures had commenced, I of course imagined I had been unsuccessful, and reluctantly entered into other engagements. I afterwards received from South Kensing on a letter dated October 16 (just one fortnight after the first lecture had been delivered), saying:-"You have obtained a Royal Exhibition to the Royal School of Mines, and request that you would join as soon as possible, as the session has already commenced." Now, Sir, it is not likely mine is a solitary instance; but is it not very disappointing, to say the least of it, that candidates should be unable to have the reward of their exertions and expense because of the dilatoriness of some lazy Government official? Having by this communication warned future candidates of the treatment they are liable to receive, and, perhaps, prevented them from suffering a similar disappointment to mine, I will no longer trespass on your valuable space. I am, &c. ALFRED H. ALLEN. 1, Surrey Street, Sheffield, November 7 NEWS Effects of Sulphuretted Hydrogen. To the Editor of the CHEMICAL NEWS. SIR,-Mr. Kopp mentions in his letter to you, contained in your last number, as a fact not yet noticed in print, that those workmen who have to deal with sulphuretted hydrogen suffer very much from an inflammation of the eyes. I have had occasion, in manufacturing practice, to notice this fact six years ago, when I put some workmen to stir liquors evolving this gas; one after the other was seized by an inflammation of the eyes, which caught at last myself. When proper precautions had been taken to remove the gas, the inflammation gave way at once. Like Mr. Kopp, I do not recollect having seen this curious fact mentioned in print before. I am, &c. GEO. LUNGE, Ph.D. 10, Albert-terrace, South Shields, Nov. 5. MISCELLANEOUS. Wholesale Poisoning.—A remarkable case of wholesale poisoning by mistake recently occurred in the town of Shiloh, Randolph County, Illinois. Two physicians, Drs. Campbell and Minner, residing in the town, sent to a drug store in the neighbouring village of Chester for a quantity of calomel. In the course of one day this calomel was administered to some forty persons. All of these persons were taken violently ill, and on examination had been mixed with the calomel. it was found that large quantities of corrosive sublimate Further inquiry showed that the drug thus adulterated had not been tampered with by the apothecary in Chester, for calomel mixed with corrosive sublimate was found in the warehouse of the wholesale dealer in St. Louis, from whom the retailer had purchased it; and on following up the investigation it became evident that the presence of the poison was due to the carelessness of the British manufacturer of the calomel. Seven of the victims of this dreadful mistake have already died in the town of Shiloh alone. How much further the results of the blunder have extended or will extend it is now impossible to say. The St. Louis dealer had sent the adulterated calomel all over the South-west, as well as to many sections in the West, and while the authorities are doing their best to obtain possession of the "doctored" stuff, it is not impossible that the fatal results of its use have not yet ended.-American Cor. of Standard. Action of Chlorine on Aloes.-Dr. C. Finckh has repeated Roubiguet's experiments, and found that the action of chlorine, whether on an aqueous or alcoholic solution of aloes, produces only chloranil Cl ̧ ̧.— Annal. der Chem. und Pharm., 134, 241. ANSWERS TO CORRESPONDENTS. All Editorial Communications are to be addressed to the EDITOR, and Advertisements and Business Communications to the PUBLISHER, at the Office,, Wine Office Court, Fleet Street, London, E. C. Private letters for the Editor must be so marked. In publishing letters from our Correspondents we do not thereby adopt the views of the writers. Our intention to give both sides of a question will frequently oblige us to publish opinions with which we do not agree. W. H. J. T.-The oxalic acid process would be the cheapest. Mr. Walker's communication is unavoidably postponed until next week. The patents have not reached us. under the circumstances; but if any did no oxygen would be evolved. F. H. S.-We do not believe that any reaction would take place R-ceived with Thanks.-Professor How, Nova Scotia; Jeremias; B. W. Gibsone, F.C.S. Books Received.-"Rinderpest, its Prevention and Cure; and Gypsum as a Sanitary Agent," by J. J. Lundy, F.G.S., &c. NEWS SCIENTIFIC AND ANALYTICAL CHEMISTRY. A Lecture Experiment, by K. KRAUT.* TAKE a platinum wire o'5 mm. thick, and wind it fifteen or twenty times around a lead pencil, so as to form a spiral; when made, pass one end of the wire through a cork, and let the spiral hang into a wide-necked flask standing on wire gauze over a lamp. The cork must be loosely laid lengthwise over the mouth of the flask. Pour into the flask so much liquor ammonia (20 per cent.) as almost to reach to the end of the spiral. Carry a glass tube, about 10 mm. wide, from a gasometer full of oxygen, into the flask, so that the end of the tube may dip a little under the ammonia. Now make the platinum spiral red hot, and allow the oxygen to enter. The platinum soon becomes heated to a bright red heat, and the flask is filled first with white vapours of nitrite of ammonia, and then with deep red vapour of nitrous acid; the glass tube which carries the oxygen becomes coated with a thick crust of nitrite of ammonia. If now the lamp under the flask be lighted and the ammonia heated, the mixture of ammoniacal gas and oxygen explodes with a quite harmless explosion. By this the platinum spiral is cooled below the temperature of a red heat; but after a few moments it again becomes a bright red, and the gaseous mixture is exploded as before, so that the experiment goes on repeating itself as long as desired. On introducing a very rapid stream of oxygen the gas burns for some time under the liquid. It concontinues to burn, producing the long-drawn sound of the chemical harmonica if the opening of the tube be held immediately above the level of the ammonia and quite close to the platinum spiral. The oxygen-ammonia flame then appears as a greenish yellow bubble at the mouth of the tube, which may be moved up and down without extinguishing the flame. IN the examination of mineral bodies for antimony, the test substance is often roasted in an open tube for the production of a white sublimate. The presence of antimony in this substance may be detected by the following process-a method more especially available when the operator has only a portable blowpipe-case at his command:-The portion of the tube to which the chief part of the sublimate is attached is to be cut off by a triangular file, and dropped into a test tube containing some tartaric acid dissolved in water. This being warmed or gently boiled, a part at least of the sublimate will be dissolved. Some bisulphate of potasheither alone, or mixed with some carb.-soda and a little borax, the latter to prevent absorption-is then to be fused on charcoal in a reducing flame; and the alkaline sulphide thus produced is to be removed by the point of the knife-blade, and placed in a small porcelain capsule. The hepatic mass is most easily separated from the charcoal by removing it before it has time to solidify. Some of the tartaric acid solution is then to be dropped upon it, when the well known orange-coloured precipitate of SbS, will at once result. In performing this test, it is as well to employ a somewhat large fragment of the test substance, so as to obtain a thick deposit in the tube. It is advisable also * Annalen der Chemie und Pharmacie, October, 1865, p. 69. VOL. XII, No. 311.-NOVEMBER 17, 1865. to hold the tube in not too inclined a position, in order to let but a moderate current of air pass through it; and care must be taken not to expose the sublimate to the action of the flame, otherwise it might be converted almost wholly into a compound of SbO, and SbO,, the greater part of which would remain undissolved in the tartaric acid solid. A sublimate of arsenious acid, treated in this manner, would, of course, yield a yellow precipitate, easily distinguishable by its colour, however, from the deep orange antimonial sulphide. The crystalline character, &c., of this sublimate would also effectually prevent any chance of misconception. Detection of Minute Traces of Copper in Iron Pyrites and other Bodies, by E. CHAPMAN, Ph.D., Professor of Mineralogy and Geology, Toronto. ALTHOUGH an exceedingly small percentage of copper may be detected in blowpipe experiments by the reducing process, as well as by the azure-blue coloration of the flame when the test-matter is moistened with chlorhydric acid, these methods fail in certain extreme cases to give satisfactory results. It often happens that veins of iron pyrites lead at greater depths to copper pyrites. In this case, according to the experience of the writer, the iron pyrites will almost invariably hold minute traces of copper. Hence the desirability, on exploring expeditions more especially, of some ready test by which, without the necessity of employing acids or other bulky and difficultly portable reagents, these traces of copper may be detected. The following simple method will be found to answer the purpose:The test substance, in powder, must first be roasted on charcoal, or, better, on a fragment of porcelain,† in order to drive off the sulphur. A small portion of the roasted ore is then to be fused on platinum wire with phosphor salt; and some bisulphate of potash is to be added to the glass (without this being removed from the wire) in two or three successive portions, or until the glass beto be shaken off the platinum loop into a small capsule, and comes more or less saturated. This effected, the bead is treated with boiling water, by which either the whole or the greater part will be dissolved; and the solution is finally to be tested with a small fragment of ferrocyanide of potassium ("yellow prussiate "). If copper be present in more than traces, this reagent, it is well known, will produce a deep red precipitate. If the copper be present in smaller quantity that is, in exceedingly minute traces-the precipitate will be brown or brownish-black; and if copper be entirely absent, the precipitate will be blue or green-assuming, of course, that iron pyrites or some other ferruginous substance is operated upon. In this experiment the preliminary fusion with phosphor salt greatly facilitates the after solution of the substance in bisulphate of potash. In some instances, indeed, no solution takes place if this preliminary treatment with phosphor salt be omitted. In blowpipe practice-as far. at least, as this is possible-the operator should make it an essential aim to render himself independent of the use of mineral acids and other liquid and inconvenient reagents of a similar character. If these reagents cannot be disused with altogether, their use, by improved processes, may be greatly limited. In the roasting of metallic sulphides. &c., the writer has emlain, such as result from the breakage of crucibles and other vessels of that material. The test substance is crushed to powder, moistened slightly, and spread over the surface of the porcelain; and when the operation is finished, the powder is easily scraped off by the point of a knife-blade or small steel spatula. In roasting operations, rarely more than a dull red heat is required; but these porcelain fragments may be rendered white-hot, if such be necessary, without risk of fracture.-Canadian Journal, September, 1860. ployed, for some years, small fragments of Berlin or Meissen porce |