256 Estimation of Iron in the State of a Peroxide Salt. { CHEMICAL NEWS, Nov. 25, 1870. IMPROVED METHOD FOR THE IN THE STATE OF A PEROXIDE SALT BY MEANS OF HYPOSULPHITE OF SODA. By M. A. C. OUDEMANS, jun. ment. It appears at least to show that the chemical constitution of a volatile medium affords no indication of its DIRECT QUANTITATIVE ESTIMATION OF IRON energy in preventing the development of fungi. What agent could be expected more profoundly to alter the chemical atmospheric conditions than chloride of lime? Its power as an oxidiser, and collaterally a deoxidiser of aqueous vapour, requires no comment. Yet it was precisely this that was inferior to all the other media, many of which could be shown to exert no perceptible chemical influence in restraining the manifestations of vitality. The observation, however, agrees with that of Hallier, who found mycoderms, vegetating fibres, and oidium forms in the presence of chlorides of the alkalies and alkaline earths. Expt. 5.-In some of the experiments before recorded the results seem to show that there was less evidence of organisation in a putrescible fluid when a toxic agent was mingled with the air supplied to it, than when the toxic agent was mingled with the fluid itself. This appeared so important as to require further investigation; for it might have a very strong influence in determining the truth between the two theories. For if the doctrine of spontaneous evolution were true, it would, surely, be more probable that the action of any chemical or poisonous agent in repressing the manifestations of life would be most pronounced when mingled with the particles whence vital evolution was proceeding, and least so when only mingled with the atmosphere with which the fluids were in relation. On the other hand, if the germ theory were true, it would be more likely that there would be less fertility when the repressive agent was absent from the fluid and present in the superincumbent air, as the toxic agency would be directly exerted upon the air-germs. A series of stoppered glass bottles of two ounces capacity was obtained; to the stoppers of some of them were fixed small pieces of sponge. The bottles were then each one-quarter filled with filtered infusion of turnip. Equal quantities of the agents hereafter named were then in the one instance added to the fluid, and in the other dropped upon the sponge so as to become volatilised into the air contained in the bottle. After seventeen days, during which the unmodified infusion of turnip passed through its various stages of putrescence, developing, first, vibrios and bacteria; secondly, fungus spores; thirdly, branching penicillium, which bore abundant fructification, the infusions were examined with the following results : Sulphurous acid (1) in the fluid: Abundant vibrios and bacteria in all parts; at the surface innumerable leptothrix chains and fungoid fibres. Sulphurous acid (2) in the air: Vibrios and bacteria in fluid; on the surface not a trace of a fungoid spore or organism. Ammonium hydrate (1) in the fluid: Vibrios and bacteria in fluid; on the surface, mass of density-interlacing penicillium, and multitudes of spores. Ammonium hydrate (2), in the air: Vibrios and bacteria in the fluid; on the surface, no trace of fungoid organism. It seems difficult to reconcile these results with any other view than with that of the air-containing fungoid spores, which were killed in the presence of a volatile agent which acted as a direct poison upon it. Vibrios and bacteria, whose germs probably exist intermingled with every drop of the liquid, were alike abundant under both conditions, the poisonous agent being too weak to influence them as it was too weak to influence the fungi which developed when the air did not contain the volatile agent. From the convergence of many methods of investigation and modes of thought, it seems, therefore, that the germ theory presents the strongest claims for acceptance. It suggests that beyond the confines of the visible world there is probably a world of living things almost inconceivably minute, but possessing varying characteristics. Into this world of beings yet unseen it will be the province of science yet to penetrate. DR. SCHERER was the first to propose the estimation of iron as peroxide, by means of hyposulphite of soda to be added in aqueous solution to the solution of the ferric iron salt until a violet colouration ceased to be produced." Dr. F. Mohr pointed out that this method was inaccurate. inasmuch as that, at the moment the reaction appeared finished, there was already an excess of the hyposulphite of soda added, which cannot be well estimated, because it is decomposed by the free acid of the iron solution, owing to the absolute necessity of applying heat. MM. Kremer and Landolt tried to remedy this defect by the addition of acetate of soda to the iron solution in hydrochloric acid, the effect of which addition would be the setting free of acetic acid, which does not decompose hyposulphite of soda, and made it possible to estimate any excess of that latter salt, after the reduction of the sesquioxide of iron had taken place, by means of a solution of iodine. By a lucky incident, I have found the means of executing the direct estimation of peroxide of iron, in one and the same operation, without the necessity of previous reduction of the iron; and my method leaves nothing to be desired as regards its accuracy. Before I describe this method, I will pay some attention to the reaction of hyposulphite of soda upon a solution of sesquioxide of iron containing free hydrochloric acid. Hyposulphite of soda is readily decomposed by all mineral acids, even when they are largely diluted; and there is no difference in this respect, whether the acid be poured into the saline solution of the latter into the acid. But, when hydrochloric acid is added to a not too concentrated solution of a persalt of iron, and there is next cautiously added to that solution a solution of hyposulphite of soda, care being taken to avoid an excess of the latter, no sulphurous acid is given off; neither is any sulphur precipitated when the operation is conducted in the cold, since the hyposulphurous acid is, under these conditions, converted into tetrathionic acid2S2O3Na2+Fe2C16+2HCl=S4O6H2+4NaCl +2FeCl2. When some chloride of barium is added to a solution of perchloride of iron thus reduced, it is easy to see that not a trace even of sulphuric acid is formed. It is true that, when the fluid before alluded to is boiled, even if it contains no excess of hyposulphite of soda at all, the free tetrathionic acid is decomposed, and that chloride of barium will detect sulphuric acid; but the ensuing precipitate of sulphate of baryta is, according to my experience, exceedingly small, and out of all proportion with the total quantity of tetrathionic acid. I have, moreover, found that, even when the liquid is cautiously heated, it is not quite possible to obtain a correct estimation of the quantity of peroxide of iron by means of hyposulphite of soda, sulphocyanide of potassium being used as a reagent to indicate the end of the operation; yet the results I obtained were better than I at first expected, being only about from 2-100ths to 6-10oths too high. The use of the following method eliminates, I am happy to say, all the defects of this method, which thus becomes available for the correct, ready, and easy estimation of the peroxide of iron in an acid solution:-I add to the iron solution, which may even contain a goodly excess of free chlorhydric acid, one or two drops of a solution of any salt of oxide of copper, and, next, as much of a solution of sulphocyanide of potassium as will suffice for imparting to the iron solution a deep red colour (for this purpose, I take from 2 to 5 c.c. of a solution of this salt at i per cent). I next pour from the burette the solution of hyposulphite of soda, whereby it will be seen that the well-known violet * Zeitschr. f. Anal. Chem., vol. i., p. 214. colouration which ensues temporarily when solutions of pure iron and hyposulphite of soda come into contact does not, in this instance, make its appearance; but the red colouration, due to the sulphocyanide, gradually fades away by the addition of the hyposulphite (this decolouration is especially very marked where the liquids meet each other.) At first, the addition of the hyposulphite of soda solution may be made freely; but, when a certain quantity of that fluid has been added (care being taken to stir the iron solution well), it is necessary to add the hyposulphite drop by drop, and to wait a few seconds before a drop more is added. With a little practice, the operator soon learns when the end of the operation is about to be reached. At last, the liquid becomes as colourless as pure water, provided not too much of the copper solution has been added. The iron solution may be heated to 40°, not only without any danger, but with the decided advantage of accelerating the reaction, especially towards the end cf the operation, which, however, whether heat be applied or not, can be performed in a few minutes. The copper salt is to be considered as the cause of the reduction of the iron, it being my opinion that the reducing action of the hyposulphite of soda is first exercised upon the salt of copper, which, in its turn, reacts upon the iron salt; and the former appears to undergo, alternately, reduction and oxidation, and thus to aid the reaction and to play a somewhat catalytic part. The quantity of copper salt required is very small indeed, because I have seen even that so small a quantity as of a milligrm. of crystallised sulphate of copper exerts a marked effect; I also found that other substances, among them nitric acid, exert an analogous action, but also disturb the regularity of the process. When the iron solution has become quite colourless, the cupric salt is, in its turn, permanently reduced to a cuprous salt; and, if the cupric salt were not added in too small quantity, there is, after awhile, a whitish precipitate of subsulphocyanide of copper formed. I am not aware (and, therefore, call attention to this en passant) whether anyone has pointed out how the reduction of cupric to cuprous salts is brought about by hyposulphite of soda. My experience has taught me that, by this reduction, tetrathionic acid is also formed; and if I admit, as is done by most chemists, the formation of a double hyposulphite of soda and of suboxide of copper, this reaction may be formulated as follows:4S2O3Na+2SO4Cu=2SO4Na2+S4O6Na2+S4O6CuNa. Returning to our subject, I state, in the first place, that my large experience has proved to me that the use of the sulphocyanide of potassium as an indicator is, notwithstanding all that has been alleged against its use in this process by M. Mohr, perfectly safe, and not in the least inconvenient. As regards the concentration of the iron solution and the quantity of free acid, the operator has a great latitude in this mode of operation, but it will be clear that too great excesses are to be avoided. As regards the accuracy of this method, I shall communicate some results, but desire to observe, first, yet, that the estimation of iron by this method is not interfered with by the presence of the salts of alkalies, strontian, lime, magnesia, protoxide of manganese, and alumina; neither do the salts of nickel, cobalt, or copper interfere, provided they are not present in so large a quantity as to become a hindrance by the colours they might impart to the iron solution. The test solution of hyposulphite of soda (at 1-10th of normal standard) I prepared by dissolving 248 grms. of the perfectly pure salt in 1 litre of water, taking care to test this solution repeatedly with re-sublimed iodine. I also dissolved 24 1 grms. of iron and ammonia-alum in 500 c.c. of water, and added some c.c. of concentrated hydrochloric acid. Each c.c. of this solution ought to correspond to I c.c. of the solution of hyposulphite of soda. I foundSO.Na.. Iron solution. IO C.C. = IO'O C.C. 40 "" = 40'0 Iron solution. 100 C.C. = 100*50 c.c. 24'95 " 25 = 25, = 25'00", The following experiments were made so as to preclude any preconceived notion about the quantity of iron taken for experiment, care being taken to estimate the quantity of iron only after the end of the assays with the hyposulphite-3576 grms. of iron and ammonia-alum were dissolved in water, some hydrochloric acid added, and the solution made up to 300 c.c.; the average result of three assays was, that the quantity of iron, Fe2O3, found was o5932, and the quantity calculated o'5934. In another experiment of the same kind, with 40200 grms. of the same salt, also made up to 300 c.c. solution, the quantity of iron found was o6656, and the calculated quantity 06672. 26055 grms. of the same salt, treated as above mentioned, and made up to a solution of 250 c.c., gave, as result, 0'4300 of Fe2O3 found, and 0'4325 of the same calculated. 04980 grms. of fine piano-wire were dissolved as already stated, in chlorhydric acid, and the liquid made up to 300 c.c. 100 c.c. of this solution required, for three assays, respectively, 298, 29'6, and 29.6 c.c. S2O,Na2; the quantity of iron, Fe, found amounted, on average of the three experiments, to o'4985, while the quantity calculated (taking the wire to contain 99.7 per cent of metal) amounts to o'4965. Influence of the Degree of Dilution.-25 c.c. of standard solution of Fe,Cl6 at 1-1oth normal required 25 c.c. S20,Na2 at 1-10th normal; 25 c.c. of the same solution of iron, diluted with 50 c.c. of water, required 25.05 c.c. of the same hyposulphite solution; 10 c.c. of the iron and 100 c.c. of water required 100 c.c. of the hyposulphite solution. (Under these conditions, the experiments require more time.) In order to test whether a more concentrated solution presented any difficulties, the following experiments were made:-I dissolved o 1953 grms. of piano-wire in hydrochloric acid, added chlorate of potassa, well acidified the fluid, boiled, and made up with water to I next added the hyposulphite standard solution, of which I used 349 c.c., giving as result, Fe-found, o'1946; calculated (at 997 per cent, as above), o'1954. 33680 grms. of sulphate of iron and ammonia (ammoniaalum) were dissolved in a small quantity of water, and the iron oxidised with chlorate of potassa; HCl was next added in excess, and the liquid boiled, and afterwards made up to 150 c.c. The quantity of standard hyposulphite solution required was 857 c.c. iron, Fe-found, 0'4799; calculated, o'4811. 20 C.C. Influence of the Free Hydrochloric Acid.-25 c.c. of the Fe2C16 standard solution at 1-10th normal and I c.c. of strong HCl required 25'0 c.c. S2O3Na2. Hyposulphite solution (standard). C.C. 2 required 25'0 25 3 4 25 258 Professor Williamson on Fermentation. Beilstein, No. 11, 1870), the addition of a few drops of a solution of a salt of copper, as directed by the author of the paper above mentioned, is unnecessary, M. Popp having found that the reaction and operation succeed perfectly if the iron solution is heated to 40° without any addition of a salt of copper.-Ed. C. N.] ON FERMENTATION.* By Professor A. W. WILLIAMSON F.R.S. (Continued from p. 248). LECTURE I. I OUGHT, however, in justice to the wonderful process which I alluded to, to give you two or three other particulars regarding it. I showed that sugar is broken up by the ferment into these products, but no case is known of pure sugar-and when I say pure sugar, I mean sugar in the purest form in which we have it-being decomposed by yeast. If you were to put some ready-made yeastthriving, growing, yeast-into a solution of chemically pure sugar, some of your yeast would decompose, some of it would resolve itself into other products, and other parts of it would be absorbing those products which are present in the liquid, and whenever the process is to be carried on advantageously and rapidly, it is customary to add some saccharine liquid-some other substance capable of nourishing the yeast. When I want good fermentation I do not take water to dissolve my sugar, and put yeast into it, but I boil some of this malt, which is one of the best materials for the purpose, in water, and take a decoction of malt, or decoction of yeast, and put the sugar into it. In such a liquid there are several bodies which we know; and I may safely say that there are a great many others which we do not know, and there is no doubt that their presence is of considerable importance to the chemical change which takes place. There are substances which I shall presently have occasion to show you and to speak of, formed by the germination of the grain, by the formation of the malt, which are related somewhat to this body which I have here. This was some pure wheat flour -every kind of flour would not do-and it is supposed that some people mix other materials with flour. It was kneaded up with water, pressed together, and, whilst the pressure was being continued, water was allowed to trickle over it. I have in another bottle some of the water that flowed over it. There is a white substance deposited from this water, which is commonly known and much used by the name of starch, and starch is, in its chemical composition, first cousin to sugar; it is a substance which passes over very readily into a kind of sugar by a process I shall presently have occasion to allude to. But the little ball of flour while being kneaded had the starch washed away from it, and I have left, as the result, a substance which is commonly known by the name of gluten. If I were to describe it in chemical language, I should say it is something like flesh, or the muscular fibre of animals, for, in chemical composition, it approaches very nearly to that. When barley is malted, and kept in a warm place for some time, the grains begin to germinate and decompose, and some bodies are formed from this gluten, which is partially broken up. The malt contains also some sugar made from that starch-grape sugar, as we usually call it. If we had only those extreme cases, I really do not know what we should do. If we had in our science one set of bodies which appeared so constantly to act at variance with the general laws which the others obey, I think we could not call chemistry a science. I have taken two or three examples to show you the definite proportions which we find to regulate the ordinary process of combination. I might have taken thousands, but the The Cantor Lectures. Delivered before the Society of Arts, CHEMICAL NEWS, Nov. 25, 1870. point is that this law does not appear to apply at all to these chemical changes which we call fermentation. One of the active substances in fermentation is being formed, it is increasing, not disappearing at all, and the contradiction is so strong and manifest that the only way out of the difficulty will be to do something of the kind which I was speaking of some time ago, that is to say, see if we cannot get some intermediate facts which will serve to connect the extreme ones; to see if we cannot get at first something between the two classes, and then try to get some further links between them. There are processes of chemical change-I will not call them processes of fermentation, for I do not know whether they are, but which are analogous to it, and some of them are very interesting and very beautiful. I have here a substance called amygdalin, made from bitter almonds. It is a bitter tasting substance, and consists of four elements which it is not necessary that I should name. In this other bottle I have a paste formed of sweet almonds, which have been crushed with a pestle and mortar, and flask. Into the mixture I will put some of this amygdalin. I will put some of it into the warm distilled water in this If I were to leave it without that addition, there would be very little change; the substance would gradually subside, but there would be no product given off in the way you will presently see. After letting it stand for a few minutes, I will pour some of the mixture into an open vessel, and we shall be able, without difficulty, to perceive a fragrant smell, which is due to the presence of a liquid of which I have a quantity here, a substance known by the name of oil of bitter almonds. If we were to perform the same experiment on a large scale, and macerate some of this amygdalin with almond paste, put them together with warm water, distil the mixture, and collect what comes over, we should find that water would pass over, and with it would be a few drops of oil of bitter almonds, and is in the sweet almond paste a substance which I cannot the amygdalin would be decomposed in the process. There describe in better terms than by comparing it to that gluten which I showed you just now. It is very similar to it in its composition, and by the contact of this, the synaptase, as it is called, with the amygdalin the elements of the amygdalin are broken up into several products; one of them is the oil of bitter almonds, another is prussic acid, which generally accompanies the oil, the third is a variety of sugar of the kind which is called grape-sugar, and there is probably also some formic acid. Here we have the breaking up of a complex body, amygdalin, into several simpler bodies by the action of the body called synaptase; but there is not in the process, as far as I know, any living organism at work. There is a substance which is somewhat similar to these living organisms, but there is no organised structure, as far as our knowledge goes at present. We let Take another experiment. I have here something which is not a blanc mange, although it looks something like it; it cool, and then turned it out; some was put into a flask it was made by boiling potato starch with water. with two or three ounces of crushed malt. It was warmed to a temperature of 60° C. for about an hour; there was cloth to keep back the husks of the malt, and here is the no boiling. The substance was then squeezed through a liquid which ran through. It is perfectly liquid, and its consistency is entirely different from that of starch, from there is a large quantity of sugar in it. There is also which it was made; it is quite sweet to the taste, and another body which we class with the sugars; that is, there is in this liquid a good deal of a kind of gum, which we call dextrine, which would easily pass into sugar. The starch, when it was being converted by the action of the malt into those soluble bodies, did no, so far as we know, break up into simpler substances; the process was of a different kind. It assimilated the water-the starch combined with the water, and at the same time divided itself, some of it forming one and some the other product. Here, also, there was not, as far as my know CHEMICAL NEWS, Nov. 25, 1870. Precipitation of Antimonous Sulphide from Boiling Solutions. ledge goes, any ferment, or any organised cells in the It is Another change of the same kind I may mention, especially as the subject of it is in itself interesting. I have here a substance which people have been accused of making for the purpose of adulterating quinine. made from willow bark, and is believed to possess febrifuge qualities, so that there was some little excuse for what I have mentioned. This substance is called salicine, and when heated with dilute sulphuric acid, in the same way as the starch when so heated, was converted into sugar and dextrine; this salicine breaks up in a way which I might compare with that in which some bodies are broken up by fermentation. 259 of gas passing uninterruptedly until the voluminous sulphide has become a dense granular powder occupying but a small portion of the original volume of the sulphide. The sulphide may then be washed with great facility, and dried upon a sand filter at 200-300° C. All the determinations of antimony made in the laboratory of the Lawrence Scientific School for some years have been executed in this manner, the results leaving nothing to be desired. Arsenious sulphide does not become granular and dense under the same circumstances. In this connection, I may be permitted to mention that the sulphides of nickel and cobalt, when precipitated from boiling solutions in the manner recommended by Professor Gibbs some years since, should be filtered off, and washed immediately after precipitation. In this manner, there is no oxidation upon the filter, even during the drying of the precipitate. But, if the sulphides are allowed to stand in the solution from which they have been precipitated, for even a few hours, they will usually oxidise upon the filter during the washing.-American Journal of Science. PROCEEDINGS OF SOCIETIES. CHEMICAL SOCIETY. THE following papers were read : "Mineralogical Notices," by Prof. MASKELYNE and Dr. FLIGHT. The contents of this communication were:1. On the Formation of Basic Cupric Sulphate.-In 1867, M. Pisani described a mineral which he supposed to be the Woodwardite of Mr. Church. The substance, however, is not the latter mineral. It had previously been examined in the Laboratory of the British Museum, and the results sufficiently tallied with those of M. Pisani to identify the mineral. It can be divided into an inner layer and an outer crust. The first consists of Another case of same kind is afforded by tannin, a substance extracted from gall nuts, and which is present in oak and many other barks. It is used for combining with gelatine, which is the principal constituent in hides, to form Professor WILLIAMSON, F.R.S., President, in the Chair, leather. If we dissolve this tannin in water, and leave it in an open vessel, it will get mouldy ;nd if you examined it a some time you would find none of it left. It would all disappear, just like sugar in the process of fermentation, and in place of it you would find, in that particular process, a body which you might easily crystallise out from the liquid, and which I have here; it is called gallic acid. It is a body resembling tannin in some respects, for instance, in the property of forming, in combination with iron, a dark substance, which is used in suspension in water, for writing ink. But it will not do to form leather in com. bination with gelatine. If you left the tannin in an open vessel, it would decompose, and there would be left gallic acid, and some other material which was formed at the same time would have disappeared. By boiling tannin with dilute acid, we get the process performed more regularly. Upon boiling some tannin with dilute sulphuric acid, you would find that water would be taken up by it, the tannin would combine with water, and it would break up into sugar and gallic acid, the process being exactly like that which I mentioned in the case of salicine. There is a Copper oxide 24'561 23.063 0'086 Magnesium oxide 0'749 Sulphuric anhydride. 6.775 Silicic anhydride 6.689 Water .. 38.528 100'451 Copper oxide most direct analogy between the process of breaking up The crust is thus composed- PRECIPITATION ON THE OF ANTIMONOUS SULPHIDE In the precipitation of antimonous sulphide, I have found it of very great advantage to employ the following process: Into the solution, containing, as usual, tartaric and free chlorhydric acid, a current of sulphydric acid gas is to be passed, the liquid being, during the passage of the gas, gradually heated to the boiling-point. The boiling is then to be continued for fifteen or twenty minutes, the current These numbers give us but little insight into the constitution of the mixed minerals. The only interest they offer is in the light they seem to throw on the possible modes of the formation of native basic cupric sulphates. The actions of solutions of magnesium or calcium sulphate on malachite may terminate in the production of Langite. An experiment in the Laboratory showed that an insoluble cupric sulphate and acid magnesium carbonate were actually formed. 2. Opal from Waddela Plain, Abyssinia.-Mr. Markham presented to the British Museum some remarkable speci Iron peroxide O'933 Manganese peroxide.. trace Calcium oxide Magnesium oxide O'137 0'311 100.648 Phosphoric anhydride 99'712 This specimen stands intermediate between the blue and brown crystalline varieties on the one hand, and the blue earthy mineral on the other. 6. Cronstedtite. The analysis of this mineral presented considerable difficulties, inasmuch as it was extremely which it is found. 3. Francolite, Cornwall.—Its analytical numbers point difficult to free it from the substances associated with to the formula 5[3Ca2(PO4)] CaCO +2CaF2. It is, in fact, a fluor-apatite in which one equivalent in every six of the calcium phosphate is replaced by carbonate. The crystallography of this mineral seems also to point to its not being ordinary apatite, and, in fact, to its not being the same mineral as the original Francolite from Wheal Franco. 4. Epidote and Serpentine, Iona.-A pebble, in which a green mineral traverses bright red felspar and quartz in veins, was sent by the Duke of Argyll to the British Museum. Its analysis leads to the view that it consists of a lime epidote with some 23 per cent of quartz, the former mineral having the following constitution :— 3 [2CaO,SiO2] +2 [2(AlgFe)2O3,3 SiO2]. The cronstedtite in question possesses an unusual interest from a crystallographical point of view, being one of the best defined types of hemimorphism. 7. Pholerite.-This mineral, derived from India, is of a pale flesh-white, penetrated in several places by patches and veins of a black mineral. An analysis of the fleshwhite mineral gave the following results: Two specimens of serpentine, of the same locality, gave lation to have those beautiful specimens, which are stored the general formula 3R"O,2SiO2,2H2O, in our magnificent national collections, investigated in so excellent a manner as the contents of the paper just read had shown. The next communication was a note by MR. CHAPMAN, "On the Oxides of Nitrogen." In a paper read at the last meeting of the Chemical Society, Mr Chapman mentioned that he had quantitatively estimated nitric oxide by converting it into nitric acid and determining the latter by the production and weighing of the baryta salt. Objections were then raised as to the possibility of the completeness of such a conversion. Mr. Chapman now endeavoured to show, by referring to wellknown chemical facts, that, whether N2O5, N2O4, or N2O3 be formed when NO is left with excess of oxygen over water, the final result must be the transformation into nitric acid. He, moreover, referred to the circumstance that the abovementioned facts were accepted by Schloesing, by Playfair, and Wanklyn, as sufficient to found upon them the quantitative estimation of nitric acid. As to SO, being present in his experiments, Mr. Chapman found this by special researches to be of no consequence. MR. HARCOURT reasserted that, on his passing nitric oxide into oxygen, he obtained, as result, nitric peroxide; when reversing this order, and passing oxygen into nitric oxide, a mixture of N2O4 and N2O3 seems to be formed. Mr Chapman replied that the different results obtained by Mr. Harcourt and by himself were, in all probability, due to differences of the temperatures at which the respective experiments had been executed. PROFESSOR WILLIAMSON took occasion of this repeated mentioning of nitric peroxide to remark that this compound may be viewed as NO i.e., as water in which the one hydrogen was replaced by NO, the other by NO2. The Society then adjourned to December 1st, when Mr. Perkin will read a paper "On some Derivatives of Anthracene." GLASGOW PHILOSOPHICAL SOCIETY. These numbers may be interpreted as representing 5 equivalents of octahydrated ferrous orthophosphate with I equivalent of octahydrated diferric phosphate, mixed with four equivalents of ferrous carbonate. The British Museum possesses some fine crystals of vivianite from Fernando Po, the chemical examination of which gave | THE annual general meeting was held in the Society's as results: rooms, Corporation Buildings, on Monday evening, the (CHEMICAL SECTION). |