was the case with the iodide heated in close vessels for some hours to 100, then to 150°. The colourless iodide of starch has then no existence; the so-called iodide of starch is simply starch tinted by iodine. Heat thus separates the iodine from the starch; the iodine then remains in the water, either as such or as hydriodic acid.

M. A. Girard has recently invented a new process for the manufacture of white lead. The lead is first prepared for treatment by granulating it; the granulated metal is placed in a rotating cask (which should be made of beech or elm, not oak) with one-fourth its weight of pure water. The cask is made to rotate at the rate of thirty or forty turns a minute, and arrangements are made for the passage of a current of air during the rotation. After about two hours, nearly the whole of the lead is found to be oxidised, and then carbonic acid is introduced in the place of the current of air, and the rotation continued for four or five hours further. At the end of this time nearly the whole of the lead is found to be converted into hydrated carbonate, fine white lead, which can be separated from all the metal. remaining intact by decantation.

At a meeting of the Société de Pharmacie, M. Mialle gave an account of kis researches on the preservation of ferments. The conclusion to be drawn from these researches is, that physiological ferments can retain indefinitely their action when suitably dried. This fact confirms the assertion of Rouchoux relative to the activity of dry vaccine lymph, and Mangili's relative to the dried poison of the snake.

M. Vigier read at the same meeting a communication on the therapeutic employment of phosphide of zinc by M. Curie and himself. The phosphuretted preparations in use, he said, offer such great inconveniences as to create a serious obstacle to the employment of phosphorus in therapeuties; they are either repugnant to the taste, or uncertain. Phosphide of zine, on the contrary, unites the conditions of an excellent medicament, and seems destined to replace all the other preparations of phosphorus; it is a grey crystalline substance, perfectly definite, unalterable in moist air, and still decomposed by the juices of the stomach. This phosphide produces in animals poisoned by it the same effects as phosphorusalteration of the blood, congestion of the lungs, paralysis of the heart, alteration in the cells of the liver, &c.

PARIS, JULY STп, 1868.

Researches on indium.- A new isomer of amylic alcohol.-The carbylamines.-A new alcohol, isomeric with caprylic alcohol. UNDER the title of "Researches on indium," a valuable contribution has been added to the chemical history of this element. MM Reich and Richter, in isolating the element, dissolved the oxidised blende or the zine in hydrochloric acid, and submitted the chloride to distillation; this chloride they digested with a quantity of water insufficient to dissolve the whole; the acid residue was dissolved in water, the solution mixed with nitric acid, and supersaturated with ammonia. The precipitate, thus obtained, redissolved in acetic acid yields erude sulphide of indium. M. Winkler's paper refers (1) to the occurrence in nature of indium, (2) to the extraction of the metal, (3) to its properties, (4) to the equivalent, and (5) to its combinations. No minerai is at present known which contains a notable quantity of indium; the only blendes in which the element has been as yet observed are the Freiberg bleude and the black blende of Breinteinbrunn, or christophite, which contains 00062 per cent of indium. The extraction of indium from the blende is a tedious operation. The powdered mineral is submitted to a thorough roasting at dull redness; the roasted product contains much sulphate of zinc, nearly all the indium in the state of sulphate, but very few other soluble metallic salts. By dissolving out the soluble matters a clear liquid, slightly ferruginous, is obtained, from which metallic zinc separates the indium, as well as copper, cadmium, &c. Only traces of indium are contained in the residue after washing. The process just described is the most advantageous one when

operations are made on a large scale, but in other circumstances, to work upon the Frieberg zinc is more convenient. The metallic zine is treated by dilute sulphuric acid, in insufficient quantity to dissolve the whole. After several weeks' contact, or by ebullition with excess of zinc, there is formed a spongy metallic residue, which amounts usually to 2 per cent of the weight of zinc employed, and which contains lead, copper, cadmium, arsenic, and indium; the indium constitutes about 2 to 25 per cent of this deposit. Thus 10 kilogrammes of zinc gave M. Winkler 208 grammes of metallic residue, containing 4312 grammes of indium. To extract the indium from this deposit, concentrated sulphuric acid is added, and a sufficient heat applied to expel the excess of acid; the result is a grey pulverulent mass, which, after calcination in a crucible, becomes quite white. By digestion in water the sulphates are dissolved, with the exception of sulphate of lead. By precipitating the filtered liquor with ammonia, the impure hydrate of indium is obtained; this precipitate is redissolved in the smallest possible quantity of hydrochloric acid, sulphurous acid added to reduce the iron to the minimum state of oxidation, and the solution digested with carbonate of baryta, which precipitates the whole of the indium after sufficiently long contact. MM. Reich and Ritcher originally fixed the equivalent of indium at 372, while M. Winkler found the figure 35 8. New determinations have led him to adopt the number 37.8. One method he employed consisted in determining the amount of gold set free by the action of metallic indium on chloroaurate of sodium. As a verification, a weighed quantity of indium was dissolved in uitric acid, and the weight of oxide of indium obtained by calcination of the nitrate determined. Indium forms a suboxide, which is obtained by an incomplete reduction of the oxide by hydrogen. By placing the bulb in a bath of melted paraffine, the phases in the reduction may be observed. About 190°, the oxide of indium becomes green, or bluish green, at the same time that water is formed; at 220° to 230° the oxide becomes grey; and about 300 it remains as a black mass, at the same time that the evolution of water ceases, only to recommence at a much higher temperature. The black mass thus obtained contains metallic globules. Separated from these metallic particles, the black mass constitutes suboxide of indium; it is pyrophoric when heated, and is transformed into oxide by combustion. The composition of this oxide is expressed by the formula In20. The intermediate phases through which the oxide passes are possibly due to combinations of oxide and suboxide; thus the green product obtained at 190° contains In,O=5InO+In20; and the grey product, which is formed about 230°, possesses the formula In,O=41n0+In,0. When indium is heated to a temperature considerably above its fusing point, a grey pellicle of suboxide is formed, which finally takes a yellow tint; heated to redness the metal burns with a violet flame, and brown fumes of oxide are produced. The colour of oxide of indium is yellow, but at a red heat it is brown; the normal colour is reassumed on cooling. Oxide of indium appears to be infusible and fixed; it contains 82:53 per cent. of indium. The salts of indium are in general soluble and difficultly crystallisable; they are colourless. following are the characters exhibited by their solutions: Ammonia-white precipitate soluble in excess; tartaric acid impedes the precipitation. Potassa or soda-white precipitate, soluble in excess, but soon separating again from the solution. Carbonate of ammonia-gelatinous white precipitate, soluble in excess, but soon separating again from the solution. Carbonate of soda-precipitate insoluble in excess. Carbonate of baryta-complete precipitation of indium as carbonate or oxide. Phosphate of soda-gelatinous white precipitate, dissolved by potassa solution with great ease. Sulphuretted hydrogen-yellow or white precipitate of sulphide of indium; the precipitation is complete in alkaline solutions, partial in neutral or slightly acid solutions, nil in strongly acid solutions; in presence of acetic acid the sulphide is completely precipitated. Sulphide of am

The

monium-voluminous white precipitate. Oxalic acid-crystalline precipitate in neutral and concentrated solutions. Ferrocyanides-white precipitate; ferrideyanides and sulphocyanides, no reaction. Neutral chromate gives a yellow precipitate; the bichromate no precipitate. The hydrate of indium produced by ammonia, when dried in the air, contains 5InO, 6HO; but when dried at 100°, its composition is expressed by the formula InO, HO.

At the séance held on the 15th of June the following memoirs were communicated:-"On a new isomer of amylic alcohol," by M. Wurtz; "On a new alcohol, isomeric with caprylic alcohol," by M. de Clermont; "On the car bylamines," by M. Gautier; "Researches on Chlorophyl," by M. Filhol; "Researches on the combustion of oil: analyses of the gaseous products of the combustion of the oil from the basin of Saarbruck," by MM. Scheurer-Kestner and Mounier. M. Saix addressed a rectification to the "Theory of the pile," which he lately communicated; and M. de la Rive addressed a letter to M. Dumas, "On the theory of the phenomenon discovered by Faraday, of rotatory magnetic polarisation."

By reacting with iodide of amyl upon zinc ethyl, M. Wurtz obtained some years ago a hydrocarbon possessing the composition and the principal properties of amylene; the hydrocarbon referred to is ethyl-allyl, CH10. The hydriodate of this body, however, boiled at 147°, while the same compound of amylene boiled at 129°. Hydriodate of amylene, it is well known, is attacked and completely decomposed, at the ordinary temperature, by oxide of silver in presence of water; the hydriodate of M. Wurtz's hydrocarbon is only incompletely attacked, behaving, under these conditions, like iodide of amyl. When one distils completely, there passes in both cases a liquid denser than water, which still contains iodine, and which, nevertheless, exhales an odour of amylic alcohol. Acetate of silver is attacked more easily by hydriodate of ethyl-allyl. The silver salt is suspended in anhydrous ether, an equivalent proportion of hydriodate added, and at the end of twentyfour hours the mixture is distilled. Above 100°, an acid liquid distils, which contains acetic acid, and an acetate corresponding to the hydriodate of ethyl-allyl. To isolate this acetate, the liquid is agitated with carbonate of soda, the oil-layer desiccated with chloride of calcium, and distilled. The acetate comes over from 133 to 135°; it is a colourless liquid possessing an aromatic odour, which, at the same time, is not that of acetate of amyl. Potash decomposes it into acetate and isoamylic alcohol. Some of this alcohol was digested at the ordinary temperature with permanganate of potassium; distillation gave a small quantity of a neutral volatile liquid, which was treated with bisulphite of sodium. The crystals formed were compressed between blotting paper, and decomposed by distillation with carbonate of soda. A small quantity of a liquid, possessing an aromatic odour, and boiling about 103, was obtained. This liquid, upon an analysis, gave C=68.48, H=1178; the formula CHO requires C=6976, H=1116. This analysis, and the boiling point, prove that a small quantity of acetone is formed by oxidation with permanganate; a mixture of acetic and propionic acids is also formed. The liquid from which the acetone was volatilised having been filtered and supersaturated with sulphuric acid yielded, upon distillation, an acid liquid, which was converted into a silver salt. This salt was found by analysis to contain C=1769, H=1'06. Experiments were also made with chromic acid, and they have shown that, under the influence of oxidising agents, isoamylic alcohol (hydrate of ethyl-allyl) gives first an acetone, and afterwards splits up into propionic and acetic acids. When iodide of isoamyl is treated by acetate of silver in presence of ether, a certain amount of isoamylene (ethyl-allyl) is set free, and distils with the ether; a bromide produced therefrom, passed over from 170° to 180°. This bromide, having been heated with sodium to 100 for some days, yielded the hydrocarbon in the free state again. The hydriodate was again formed by

NEWS

heating the hydrocarbon with hydriodic acid. The hydriodate thus formed was identical with the hydriodate of ethyl-allyl: it distilled over at 145°. One would conclude from this, M. Wurtz says, that the ethyl-allyl set free by the decomposition of the hydriodate, maintains its atomic grouping intact, not only after having been converted into bromide, but even after being deprived of its bromine by sodium. The alcohol described is the third isomer of the primary hydrate of amyl; the two others being the hydrate of amylene, discovered by M. Wurtz, and the secondary alcohol, obtained by M. Friedel, by adding hydrogen to methyl-butyl.

The experiments of M. de Clermont were made in the laboratory of M. Wurtz. M. de Clermont first describes hydricdate of caprylene. When caprylene is heated with a solution of hydriodic acid saturated at zero, this compound is produced; at the end of a few hours the reaction is completed, and the hydriodate is found as an oily liquid at the bottom of the vessel. The layers being separated, the product is washed first with water, afterwards with a weak solution of potash, and then dried over chloride of calcium. This liquid is submitted to fractional distillation in vacuo, that, coming over at 120°, constitutes pure hydriodate; the specific gravity of this distillate is 133 at zero, and 1314 at 21°. By reacting in the same way with hydrobromic acid, the hydrobromate of caprylene is obtained. When hydriodate of caprylene is added to acetate of silver suspended in ether, a lively reaction ensues; iodide of silver is formed, as well as a certain quantity of caprylene and acetic acid, but a compound also, the acetate of caprylene, is obtained. Ether dissolves the fluid products. By distillation, the ether is removed; the residue is treated with water and carbonate of soda to remove the acetic acid, and dried by chloride of calcium. A liquid is thus obtained, from which the caprylene is eliminated by fractional distillation; finally, pure acetate of caprylene is obtained. It is a colourless liquid, possessing a fruity odour; its density at zero is 822, and at 26, 803; its boiling point is inferior to that of the acetate of capryl of M. Bouis, which is 193. Upon distilling in the oil-bath acetate of caprylene with an equivalent quantity of caustic potash, recently calcined, acetate of potash and hydrate of caprylene are obtained. The distillate requires rectification. The hydrate purified by fractional distillation was analysed, and the figures obtained led to the formula CHO; the liquid upon which the analysis was made boiled at 174° to 178. The hydrate of caprylene is a transparent, colourless, and very mobile liquid, not oily, and possessing an aromatic odour and a burning and persistent taste; it is inflammable, and burns with a bright flame. It is insoluble in alcohol and ether; its density at zero is 811, and at 23°, 793. Hydrochloric acid does not appear to decompose the hydrate of caprylene: but the solution of hydrochloric acid, aided by heat, gives birth to the hydrochlorate of caprylene. This hydrochlorate would be a new isomer of the chloride of capryl of M. Bouis, another having been described by M. Schorlemmer, which he obtained in treating amyl-isopropyl with chlorine.

PARIS, JULY 15TH, 1868. Cerium.-Fluorescent liquid.-Examination of the light in certain cases of phosphorescence.--Death of M. Pouillet. M. WÖHLER has published the following facts concerning the metal cerium. The metal itself was obtained by the following process:-A solution of the brown oxide of cerium in hydrochloric acid was mixed with an equivalent quantity of chloride of potassium and of chloride of ammonium, and the whole evaporated to dryness. The mass was then transferred to a platinum crucible, and heated till the whole of the chloride of ammonium was volatilised and fusion obtained. The fused mass was poured out, coarsely powdered, and mixed while still warm with fragments of sodium, * Annalen der Chem. u. Pharm., cxliv., p 190; 1867.

and introduced into an earthen crucible previously heated to redness. When the contents had again fused and the excess of sodium volatilised, the crucible was removed from the fire; the deep grey resulting mass was filled with little metallic globules. In a second experiment a large piece of sodium was thrown into a red-hot crucible containing chloride of potassium, and then the coarsely powdered chloride used before. In operating in this way, a larger proportion of metallic globules was obtained, some of which weighed 50 to 60 milligrammes. These metallic globules appear to consist principally of cerium. The colour of the metal is intermediate between the colour of iron and that of lead. The metal is lustrous when polished; it is malleable. Its density is about 55 at 12. Exposed to the air it loses its lustre, and becomes slightly blue. It feebly decomposes water at 100°. Hydrochloric acid dissolves it with energy; concentrated nitric acid converts it into clear brown oxide, the dilute acid dissolves it. By evaporation, a white salt is obtained which leaves, after calcination, a brown oxide. insoluble in nitric acid and in dilute sulphuric acid. Concentrated sulphuric acid slowly dissolves this oxide, forming a yellow solution which shows the reactions of ceric salts. Hydrochloric acid dissolves this oxide with disengagement of chlorine, forming a colourless solution. When a globule of cerium is heated by the blow-pipe to dull redness, the metal inflames and burns vividly, forming brown oxide; but upon submitting a globule suddenly to a very high temperature, it burns with explosion, sending out bluish sparks. Cerium powder can inflame below 100 ̊. When the saline mass containing the cerium globules is treated with water, a fetid hydrogen gas is liberated, and a brilliant powder of a deep purple colour is deposited, which is easily separated by washing. Dilute hydrochloric acid extracts from this powder a small quantity of metal, as well as of oxide. This body is a cerous oxychloride. Concentrated hydrochloric acid attacks it with difficulty; concentrated nitric acid dissolves it, forming a colourless solution A solution which is said to exhibit the most beautiful green fluorescence yet known is yielded by Cuba wood (Morus tinctoria). M. Ditte has prepared some alcoholic solutions, possessing remarkable fluorescent properties, with the lake of this dye wood. The process which he has found most advantageous is the following:-The lake is placed in contact with an excess of glacial acetic acid, which dissolves it completely at the end of twenty-four hours. Six times the volume of alcohol is added, and the mass filtered. The liquid thus obtained, viewed by transmitted light, is red, by reflected light, a magnificent green. Upon adding to the acetic acid solution ether quite free from alcohol, a yellow matter is precipitated, and the liquid loses its properties; the precipitate re-dissolved in alcohol, gives again a dichroic liquid. The decoction of the wood is not dichroic, but it becomes so immediately upon the addition of acetate of alumina. The fluorescent liquid, sufficiently diluted to be only slightly coloured, entirely absorbs the most refrangible part of the spectrum, from the blue to the violet. The fluorescence is not visible with the light from a lamp or gas; it is, on the contrary, very vivid with the magnesium light and in Geissler's tubes.

M. Kindt has made known the nature of the phosphorescence developed by heat in the three minerals, chlorophane, Estramadura phosphorite, and the green fluor spar. He has analysed the light emitted: the first is a simple green, the second is a yellow tinted light, composed of green, yellow and red, and the third gives two black rays, the one in the green and the other near the orange.

M. Pouillet, the eminent physicist, died on the 14th June in his 78th year. The following is a brief outline of his career:-In 1829 he became professor of physics at the Conservatoire des Arts et Metiers. In 1831, he succeeded Dulong in one of the chairs of physics at Ecole Polytechnique. On the 17th July, 1837, he entered the Academy of Sciences, in the physical section, and was

made an officer of the Legion of Honour. Among the researches published by him may be cited those on the dilation of elastic fluids and the latent heat of vapours, on the phenomena of interference and diffraction, on solar heat, the radiating and absorbing powers of the atmosphere, and the temperature of space. His memoirs, containing the experimental demonstration of the laws relating to electric currents, are worthy of special mention. It is hardly necessary to connect M. Pouillet's name with his Traité de physique et de méteorologie and his Elements de physique.

PARIS, JULY 22ND, 1868.

Influence of the condensation of the vapour of water in experiments on the absorbent power of gases.-Persulphide of hy drogen.

Ar the same time, in 1861, Professor Tyndall in London, and M. Magnus at Berlin, published their experiments on the transmission of heat through different gases. These entirely independent experiments, having nothing in common in the modus operandi, led to results in part concordant, in part discordant. By this dual research it was clearly established that the absorbent power of different gases is extremely different. But with regard to the absorbent power of the vapour of water, Professor Tyndall asserts it to be very considerable, while M. Magnus asserts it to be insignificant. When the vapour is in the state of mist, both agree in recognising that the vapour absorbs a considerable part of the heat which it receives, but when the vapour is transparent, when it presents itself as humid air, the divergence of opinion is as great as possible. In his memoir upon the production of dew, M. Magnus has demonstrated that the emissive power of dry air is equal to that of a moist air, whence results the equality of their absorbent powers. Since then M. Wild, of Berne, has made experiments which plainly confirm those of the English physicist. M. Magnus has repeated M. Wild's experiments, and while proving their perfect accuracy, he has discovered a source of error which is a complete explanation of their results. In these experiments the thermoelectric pile is placed equidistant from two cubes of hot water, from which it is separated by brass tubes. The diaphragms enable the two currents of heat to be regulated, so that the two faces of the pile are equally heated, or the galvanometer rests at zero. This equilibrium, being obtained when the tubes are filled with dry air, should remain when moist air is substituted; but this is not the case. M. Magnus has sought the cause; this he finds in the condensation of the vapour against the internal surface of the tubes. It is a great mistake to suppose that the heat undergoes no modification in passing through the tube. When the interior is polished an infinite number of reflections are produced, and the tube sends to the pile rays which would not reach there if they were absorbed. In consequence of these multiple reflections, the pile may receive six times as much heat as if the tube did not exist. Everything which will diminish the reflecting power of the sides of the tube, and everything which will augment their absorbent power, will contribute to diminish the heat which falls upon the pile. Then this effect of the condensation of the vapour of water takes place when the tube is full of moist air. The minute layer of water which is deposited on the internal surface can have but little influence when this surface is tarnished, while it will have an enormous influence in a polished tube, an excellent absorbent being superposed to a reflecting surface. What happens further? The galvanometer being at zero with the tubes full of dry air, if moist air be introduced into the one of them, the equilibrium will subsist if the tube is blackened, while it will be immediately destroyed if the tube is internally polished. The heat will appear to be absorbed by this tube; and it is in fact, but by the bed of moisture which covers the sides, and not by the moist air which fills the tube. The effect is particularly marked when the tube is

cooler than the air, but it is observable also when the tube is notably warmer, proving that the vapour condenses on the sides, even when the space is not saturated. The vapour of alcohol behaves like water and with still greater energy; the experiment in blackened tubes proves that it exerts a sufficiently notable absorption.

Dr. Hofmann has made some experiments upon the persulphide of hydrogen. When a cold saturated solution of strychnine in strong alcohol is mixed with an alcoholic solution of sulphide of ammonium containing an excess of sulphur, brilliant crystalline flakes soon make their appearance, and twelve hours later the sides of the vessel are covered with fine needles of an orange colour, often some centimetres in length. To obtain them in a state of perfect purity, it suffices, after decanting the mother liquor, to wash with cold alcohol. These crystals are completely insoluble in water, alcohol, ether, and sulphide of carbon, in fact no solvent from which they may be recrystallised has been found. An analysis of this compound has led to the following formula:-C21H24NOS3=C11H22N2O,H,S,. These crystals would then be a combination of a molecule of strychnine with a molecule of a persulphide of hydrogen, of which the composition would be expressed by the formula HS. The crystals become decolourised upon the addition of a few drops of concentrated sulphuric acid; sulphate of strychnine is formed which dissolves, while persulphide of hydrogen is separated under the form of a colourless and transparent oil. The drops of oil may be preserved for some time, but they are not long in decomposing into hydrosulphuric acid and sulphur. M. Hofmann says this combination of strychnine and persulphide of hydrogen, which can be preserved for months, leaves no doubt as to the existence of a persulphide of hydrogen (H, S3), which would thus be a sesquisulphide; other persulphides may, however, exist. The combination with strychnine is, as already mentioned, characterised by great insolubility; it remains to be seen whether this property can be utilised in the isolation of the alkaloid.

PARIS, JULY 29TH, 1868.

M. Baudrimont proposes a method of making the final reaction more delicate, by adding a few drops of solution chromate of potash to the bromide examined; the nitrate of silver added then combines with the whole of the bromine and chlorine in preference, and the complete precipitation is marked by the production of the red precipitate of chromate of silver. It is obvious that the bromide contains more or less chloride, according as the number of burette divisions (divided into 1-10th c.c.) of the silver salt required, exceeds 142. With a salt containing one-tenth of its weight of chloride of potassium 151 divisions are required, and with a mixture of equal weights of chloride and bromide, 185. The same method may be employed to recognise the degree of purity of several compounds. Operating as before-that is to say, dissolving 1 gramme of the material to be examined in 100 c.c. of distilled water, and taking 10 cc. of the solution-the following numbers of 1-10th c.c. divisions required will show the purity for at least a considerable number of salts:-102 for pure iodide of potassium, 257 for cyanide of potassium, 246 for dry carbonate of potash, 290 for chloride of sodium, 119 for carbonate of soda + 10 equivalents of water, 47 for phosphate of soda + 24 equivalents of water, and 54 for arseniate of soda + 14 equivalents of water. In a note, entitled "Researches on Chlorophyl," by M. Filhol, presented to the Academy of Sciences, he states that all the methods of preparing chlorophyl requiring the aid of acids decompose this substance, and furnish, not chlorophyl, but the products which result from its decomposition. The organic acids, the action of which is less powerful, destroy the green colour of solutions of chlorophyl; this substance splitting up into two substances, one of which separates in the solid state in the form of black flakes, while the other remains in solution, and is of a fiue yellow colour. The yellow matter, treated with concentrated hydrochloric acid, is separated into a solid substance which can be isolated by filtration, and which is yellow, and a blue substance which remains dissolved. The latter becomes yellow when the acid which has produced it is saturated. The yellow solid matter which separates when the hydrochloric determines the production of the blue colour, contracts the property of becoming blue under the influence of acids, when boiled for a few minutes with potash, soda, or baryta, in contact with the air. The green parts of the plants always contain, as well as chlorophyl, the two yellow substances spoken of. It is easy to obtain them without the intervention of acids. Treatment decolourise the solution, suffices with a solution of chlorowith animal black, in insufficient quantity to completely phyl; after a few trials the proper amount is arrived at, and, upon filtering, a yellow-coloured liquid is obtained, which behaves with hydrochloric acid like that obtained in decomposing chlorophyl with an organic acid. These two yellow matters exist, then, in the free state by the side of chlorophyl in all plants. The young shoots of certain varieties of fusanus which are cultivated as ornamental plants, contain these two yellow substances, without the least trace of chlorophyl The brown solid matter which is separated upon the addition of oxalic acid to a solution of chlorophyl is rich in nitrogen; it is identical with that described and analysed as constituting pure chlorophyl, by MM. Miller and Morot. Solutions of this brown matter possess in a high degree the dichroism common to solutions of chlorophyl; solutions of the yellow matter do not possess this property. The solutions of the brown matter become orange-yellow tinted under the influ ence of caustic alkalies and the air; this tint soon changes and becomes a pure green by absorption of oxygen.

REPORTS OF SOCIETIES.

CHEMICAL SOCIETY. Thursday, June 18th, 1868.

IN continuation of our report of this evening's proceedings

we now give abstracts of the three communications which concluded the business of the session.

Dr. W. J. PALMER contributed an interesting narrative entitled "Observations on the Production of Nitre in India." The native "sorawallahs" make it the business of their lives to search for saline incrustations in and around the mud walls which enclose the primitive dwellings of the inhabitants of the north-western provinces of India. When the appearance of the soil indicates the existence of nitre they scrape off a thin layer of the impregnated earth and lixiviate it in clay vessels either with water alone or with the last washings of a previous operation, the solution thus obtained being poured into shallow pans of unglazed earthenware, and there left exposed to the sun and hot winds of a tropical climate, until the nitre crystallises out. The crude product is then partially purified by being again dissolved and recrystallised. The saltpetre is recovered in the form of dingy prismatic crystals, and common salt to the amount of from one to nine per cent, is left in the mother liquors, which upon evaporation to dryness is recovered and separately collected. The gorawallah makes periodical visits and secures fresh collections of nitre from the same spots of ground week after week, the rate of production remaining constant whilst the dwellings are inhabited, but decreasing gradually if from any cause the villages are deserted. The physical features of the nitre-producing regions were then described, and the author referred to the conditions under which most nitre seemed to be obtained; these were dependent upon the existence in the plains of India of a friable, nodular, calcareous rock called "kunkur," and water must not occur nearer the surface than twenty feet; but it was remarked that the largest yield of nitre was furnished in the four months of the year constituting the rainy season, the heavy tropical rains having the effect of washing the salt from the depths of the soil to the surface rather than of dissolving it out entirely and carrying it into the rivers. The process of nitrification commenced with the conversion of urea, &c., into nitrate of lime, under the combined influences of heat, moisture, and of the beforementioned calcarcous rock; whilst the practice of the natives of throwing their wood ashes into the common drains supplied the carbonate of potash from which, by double decomposition, the nitre was formed. These changes only occur in the neighbourhood of villages, or densely populated localities, but the process of artificial generation of saltpetre had been successfully carried out in connexion with the Indian jails. The author adds a speculation as to the influence of electrical agencies (thunderstorms) in contributing towards a more rapid formation of saltpetre.

The PRESIDENT, in proposing a vote of thanks to Dr. Palmer, invited discussion upon the electrical theory of the gencration of nitric acid; whether all other circumstances being the same, most nitre should be formed during the season in which thunderstorms were prevalent.

Mr. W. H. PERKIN expressed his surprise in noticing how few sparks from a Rühmkorff coil sufficed to produce red fumes in a jar of air, especially if the temperature was somewhat raised, and the indigo test at once showed the presence of nitric acid.

Mr. DAVID FORBES had had opportunities of studying the saltpetre manufacture in several parts of the world. In order to ensure a supply of saltpetre in case of war, in Sweden, every peasaut was bound to supply a certain amount of nitre to the Government as part payment of the taxes. It was the practice to rely upon wood ashes from the household fires as the source of potash, the other ingredients being nearly the same as in India, with lime added where it did not occur naturally. In the cold climate of that northern latitude there was no suspicion of lightning having any direct influence upon the generation of nitric acid. Spain formerly got much saltpetre from the plains of the south, where nitrogenous organic matter was somewhat scarce, but potash abundant, as the result of the

decomposition of the felspar of the granites. In Peru, Chili, and other parts of the continent of South America, where rain never falls, immense accumulations of nitrate of soda were known to exist; in fact, it appeared only necessary to place organic matter in contact with carbonate of lime and common salt to secure the production of the nitrate of soda or Chilian saltpetre in that climate, and in these districts all the wells were so fully charged with saline matter, that it was necessary to procure water distilled from the sea with English coal at the cost of £3 or 4 per ton for ordinary household use; even the locomotives on some South American lines had to be supplied with distilled water to avoid the formation of saline crusts in the boilers. Dr. J. H. GILBERT was led to believe that the process of nitrification was practically independent of the oxidation of atmospheric nitrogen or of electrical action; some years ago he searched for ammonia and nitric acid in rain water which fell during a heavy thunderstorm, and found ammonia without difficulty, but the quantity of nitric acid was excessively small.

Mr. JOHN WILLIAMS took occasion to examine for sulphuric acid and ammonia in the rain water which fell during the thunderstorm in London about the end of May. The Nessler test immediately indicated the presence of ammonia, and the amount of sulphuric acid was by no means inconsiderable.

Dr. HUGO MULLER said it was well known that organic matter containing but little nitrogen furnished nitrate as the result of its putrescence, and it had been hinted that the oxidation of these organic matters was capable of inducing (by a sort of catalytic action) the formation of nitric acid from the surrounding atmospheric nitrogen. Schönbein proved that nitric acid was formed merely by bringing nitrogen gas in contact with flame.

Dr. GUTHRIE was desirous of assuring himself that the proceeds of the sale of nitre more than covered the cost of production under favorable circumstances of native labour. Some years ago he proposed to the Government authorities to collect saltpetre in the Mauritius, for the town lies low and near the sea, and there were difficulties in the way of securing good drainage. Not only as a commercial speculation, but as a sanitary measure, the removal of this sewage, and the conversion of it, if possible, into saltpetre seemed to be important; his advice was not adopted, and since that time his views had received confirmation by the fearful ravages of disease and high rate of mortality which had occurred in the island.

Dr. J. ATTFIELD conceived that the largest production of nitre would not coincide with the periods when thunderstorms most frequently succeeded each other, but that a necessary interval must elapse to allow time for the oxidation to proceed.

Dr. ODLING referred to an anomaly in the fact that starch paste, although destitute of nitrogen, gave off ammonia during its fermentation. For his own information he enquired whether the great bulk of nitre imported from India is made by the manurial collection plan which had just now been described?

Dr. PALMER supplemented his previous remarks by making a few statements respecting the depth at which water ordinarily occurred in the large tracts of country near the Himalayas as compared with other localities in the plains of the Ganges. There could be no doubt about the fact that nitre was collected in much greater quantity during the four months of the rainy season than at other times, but whether this circumstance was due to the more speedy recovery of the salt, already formed, by the solvent action of water resulting from heavy rains penetrating the earth to a greater depth, and by subsequent evaporation becoming reabsorbed to the surface; or to a direct influence of electrical action in promoting the nitrification, seemed to him (the speaker) well worthy of discussion, and he was only glad to have started a subject of so much interest to the members of the Society. For his own part he now thought that the