theory of the latent image, which shall serve to explain | cal relations between the unexposed and exposed silver the phenomena relied on by the supporters respectively of the present vibratory and chemical hypotheses. I would now venture to suggest an explanation of the action of light on iodide of silver which, prima facie, seems to be complete. It is well known that the atom of a chemical element is a sharply-defined relative quantity, but that the atoms of unlike matter often differ materially in the amount of chemical work they can perform; thus an atom of sulphur can represent 6 atoms of hydrogen in combination; nitrogen 5; carbon 4; boron 3; and oxygen 2 atoms of hydrogen; silver, on the contrary, only 1. But this so-called "equivalence" of an element is not absolutely fixed, for, in some of its compounds, nitrogen represents only 3 atoms of hydrogen-in ammonia, for instance-and in others, as in nitrous oxide, but I. This variation is now commonly accounted for by supposing that pairs of points of attraction on the atom of a polyequivalent element disappear by neutralising each other, and thus lie hidden in certain forms of combination. If we represent the atom of nitrogen by a circle, its pentequivalent, triequivalent, and monequivalent conditions may be thus shown: I In Nitric Acid. In Ammonia. In Nitrous Oxide. These points of attraction are now usually termed "bonds." Iodide of silver consists of 1 atom of silver and I of iodine, Now, the atom of silver is known to be equivalent to only 1 atom of hydrogen; but the study of organic and other iodine compounds teaches us that the atom of iodine is equivalent to 3 of hydrogen, though most compounds only appearing to be equivalent to 1 hydrogen atom. Representing graphically the atoms of silver and of iodine respectively by equal circles, and the equivalence of each atom by lines projecting from the circumference as usual now in graphic formulæ, we may represent ordinary iodide of silver in the following way: N Ag Here one of the three "bonds "or centres of attraction of iodine is united with the single bond of silver, the other two neutralising each other, as indicated by the dotted line, and so remaining latent. Up to this point I have advanced nothing new; but it is necessary to recognise these preliminary matters in accounting for the action of light on iodide of silver. Common experience leads us to the conclusion that in many cases the action of light chiefly consists in the severance of the union of unlike bodies held in combination by comparatively feeble affinity; and the highly interesting investigations of Dr. Budde would seem to go farther, and to prove that the same kind of action is inimical to the exercise of the still more feeble attractive force which tends to unite the atoms of like matter in molecules. We have only to extend the statement to the union of bonds in a single atom-as in the case of iodine -and we gain a perfectly intelligible conception of the nature of the influence exerted upon iodide of silver by light, and the cause of the well-known difference in chemi compound. The two conditions may be graphically represented thus: Up to the point at which it is necessary to assume that light is capable of severing the union between the latent "bonds" of iodine, the theory is in harmony with the current of thought in chemistry. But it is not yet generally admitted that a "bond" can remain free or unsatisfied. The existence of such apparently anomalous incompounds as nitric oxide and certain of the chlorine oxides has, however, led some chemists to think that certain "atomicities" in a compound may remain free, and ready to enter into new combinations on a favourable opportunity presenting itself. The experiments of Dr. Budde on chlorine strongly support such a view; and, further, when we carefully consider the action of chlorine on olefiant gas, under the influence of sunlight, I see no difficulty in supposing light actually to have the power of severing the union between the latent "bonds" of an atom. I venture to think that this could take place even more easily in some cases than could the separation between the atoms of the molecule of a simple body, orthe much more difficult case-of the disunion of the unlike atoms of a compound such as iodide of silver. If, then, the last, and as must be admitted, the least likely case to occur is that which we can, in several compounds, actually observe, we are clearly warranted in assuming the much easier, and, a priori, the more probable, change to take place also. Let us now apply the theory stated above to the explanation of some of the facts of development. I shall take at present only the case of acid development— with iron, for example-in the presence of excess of silver in the solution flooding the film. The acid present prevents the immediate deposition of metal; but still the exercise of even a very slight attractive power is capable of separating the silver from the liquid. The existence and exercise of the surplus chemical energy of the iodine atom of the exposed iodide of silver is amply sufficient to account for the attraction to the exposed iodide only of the metal silver, and this without assuming that the iodide of silver itself suffers any decomposition; in fact, the process appears to consist in the formation of a sub-iodide of silver by addition of silver to the exposed iodide, not by abstraction of iodine, as might be supposed. If such a definite compound be produced in the manner indicated, its formula most probably is Ag3I, for each of the three Unexposed. After exposure. After, as before, exposure the compound is iodide of silver; but two of the three attractive powers of the iodine are now free from each other's control, and ready to enter into new combinations. It is evident that change may now take place in either of two directions. First, the atom of iodide of silver may attract two additional atoms of silver or other analogous body to itself in so-called development; or, secondly, a complete separation of iodine from silver may arise, owing to the exercise of the superior power of the two free bonds of the former over the one attached to the silver atom. It appears by no means improbable that the first condition obtains in acid development with excess of silver, while in alkaline developement the action is more likely to be chiefly of the second kind. NEWS "bonds" of the iodine is now engaged with an atom of silver. If the film be now fully washed alter development, we have a layer of ordinary iodide of silver carrying an image formed of a sub-iodide of silver the constituents of which are held together by comparatively feeble force; but it is by no means improbable that the determination of silver to the exposed iodide in the first instance, in order that the sub-iodide may be formed, facilitates the deposition at the same time and on the same part of the film of metallic silver in addition; so that we are not to look upon the image as consisting only of the sub-iodide, but as carrying some free silver also. When the conditions of development are such as to admit of very rapid deposition of this so-called "supplementary" silver, we should expect the precipitation to be determined by that species of sympathy so often observed in chemical processes, acting even outside the sphere of attraction of the exposed iodide of silver, and thus give rise to the well-known phenomena of solarisation and of fog. Assuming the image to be free from these defects, however, its subsequent intensification results from the well-known attraction of silver for silver on the point of deposition from solution. Fixation by hyposulphite of sodium, or similar agent, in my view of the matter, consists in the decomposition of the above mentioned sub-iodide of silver, ordinary iodide of silver dissolving, and the excess of silver remaining, and forming the image in its final condition. Such is the view which I venture to take of the action of light on iodide of silver, so far as the production of the "latent image" is concerned. The most reliable experiments have proved perfectly pure iodide of silver to be sensitive to light; it is, therefore unnecessary for me to extend this paper beyond reasonable limits by discussing the details of photographic processes, in which iodide of silver plays the chief part; but I should add that, so far as I am aware, there are no facts which the theory just proposed is not capable of simply explaining. Further, when the apparently conflicting statements of the physical and chemical schools of thinkers on this subject are reconciled on the physico-chemical theory which I have advanced, we may fairly regard the latter as a safe aid to investigation. I have only to add that the above sketch of a new theory of the "latent image" is to a large extent derived from several detailed articles which I published in the last volume of the British Journal of Photography. ON THE CHEMICAL PROCESSES OF THE LIVING PLANTS. By A. EMMERLING ence of physical forces. We do not as yet possess the means of experimenting upon such a mixture, nor are we enabled to isolate therefrom single substances, nor is it at present possible to follow up all the phases of the various conversions of matter which take place, and hence we have been limited in our research to microscopical investigation of the processes going on in the protoplasma so far as these can be observed. Chemistry has taken another step in this field of research, and has tried to find out how far the growth of the plant depends on the presence of certain mineral matters, thus fixing the physiological value of the minerals to plants, as proved by Nobbe's researches. Although very valuable knowledge of the general requirements of plants in respect of mineral matters is thus obtained, we have not learnt the true chemical processes-the modus quo-how the various mineral matters act in the process of formation of the organic substances. In making experimental researches in this direction, it is necessary in the first place to discover proper methods, and I have adopted one which, so far as I know, is quite novel, and differs from other methods in that it tries to draw conclusions from facts already known, aided by experiments made beyond the interior of the plants, in order to ascertain what takes place in the interior. I considered that it might perhaps be possible to ascertain certain reactions beforehand, by relying upon certain initial facts of the agentia active in plants, and thus to learn deductively (deductiv) the further conversions or mutual reactions of matter that take place in them. While engaged in extending the chemical facts required for my ultimate conclusions, I discovered and investigated some simple reactions, the results of which I am about to describe in the following part of my essay. In the first place, I considered the conversions which the mineral salts sucked up by the roots undergo in the interior of plants. That saline solution comes into contact with the acid juices produced by the plant, which juice always contains a certain proportion of free vegetable acids, viz., oxalic, tartaric, malic, &c. Considering these organic acids to be, at least in relation to the mineral salts, the main active principles of the juices contained in plants, I thought it best to investigate their action upon such of the mineral salts as are prominently active in the nutrition of plants. Owing to the enormous extent of this field of research I had at the outset to limit my investigation to a few special points, and selected such reactions as appeared to me undoubtedly to take place within the interior of plants. It may be taken for granted that plants absorb nitrates from the soil, and also that oxalic acid is largely dispersed through them, and hence I investigated the action of oxalic acid upon the nitrates of lime, potassa, and soda. The experiments with lime salts are easily made. I used very dilute solutions, in order to imitate as much as possible what takes place in the plants themselves; I investigated the reactions between oxalic acid and nitrate of lime in all possible conditions; I determined the influof time, of degree of concentration, of excess of either of the two salts, of the presence of foreign saltsin fact, I operated in all directions. I found that oxalic acid separates a portion of the lime in the shape of a crystalline oxalate, while nitric acid is set free. The quantity of lime thus precipitated depends entirely on the conditions under which the experiment is made; the greater the dilution of the fluids and the shorter the duration of the action, the smaller is the quantity separated; but even in very dilute solutions it is relatively very large, and when the duration of the experiment is sufficiently long, the precipitation is almost complete, viz., complete decomposition of the nitrate of lime with formation of oxalate. An instance of the progress of the reaction will prove this. With a degree of dilution corresponding to 1 equivalent = 28 of lime (in the shape of nitrate of lime) and 1 equivalent of oxalic acid in 200,000 c.c. of water, there was precipitated of the 28 of lime THE chemical processes which obtain in plants are very imperfectly known to us. It is true that we are acquainted with a series of relations existing between some of the products of the materials of the vital activity of plants-ence for instance, that between chlorophyl and starch-and the manifold relations of some of the organic matters formed in plants to some of their mineral constituents, as for example the relation existing between potassa and starch, as proved by the researches of Nobbe. I must not also omit to notice the fact, that the more recent researches of organic chemistry bear upon and throw some light on the synthetical processes going on in plants; but, notwithstanding this, the efforts both of chemists and of phytophysiologists have hitherto failed to state with certainty the progress and causes of the different reactions, decomposition, or formation going on in plants. The great difficulty and obstacle to this kind of research is that the chemical reactions of the plants are chiefly taking place in the plasma of the cells, which has to be considered as a mixture of many substances, most of them unknown, which are permanently subjected to changes by the influ After 15 minutes time 18 hours 22 13 2 or 471 per cent. 20.8 74.2 70 22'4" 80'0 168 22.8 81.4 The formation of a precipitate only ceases when the liquid is highly diluted, because precipitation is then counteracted by the solubility of the oxalate of lime. I further found that the separation of oxalate of lime is increased as much by an excess of nitrate of lime as by an excess of oxalic acid, while the nitric acid acts as a solvent; I hence inferred-and found confirmed by experiment that the solvent capability of the nitric acid is lessened by the addition of oxalic acid, so that, to a certain extent, the one acid counteracts the other. As regards other and more exhaustive details, I shall have to refer my readers to my work on this subject, which is to be shortly published. The main result of my researches is therefore the following:-That, under all conditions, nitrate of lime and oxalic acid act upon each other in dilute solutions in such a manner that, while nitric acid is set free, oxalate of lim eis precipitated; and since these substances occur also in the juices of plants it is clear that there the same reactions take place, and consequently the vegetable juices must of necessity contain free nitric acid. The oxalate of lime thus separated in the plants plays the part of a by-product, which is deposited in proper spaces, either cells or membranes; this fact I elucidated by microscopic research, because I found that the oxalate of lime precipitated from the dilute solutions I operated upon is, when viewed by the microscope, distinctly crystalline, while the size and mode of grouping together of the crystals seem to depend upon the dilution of the solution. The shape of the crystals just mentioned agrees exactly with that of the oxalate of lime most frequently in plants. They are monoklincedrical prismas, belonging to the orthoclase shape, which have a great tendency to form twins, and are often united into crystalline agglomerations frequently met with in plants, and termed by botanists morning stars, on account of their peculiar shape. I have not succeeded in producing raphides artificially, but I do not doubt that I may also obtain these by a proper arrangement of the conditions of the experiments. It is clear that the investigation of the decomposition of the potassic and sodic nitrates, supposing it to take in an analogous manner, is far more difficult. Although it is a fact that, by the distillation of a mixture of nitrate of potassa and oxalic acid in the presence of a small quantity of water, fumes of nitric acid are given off, it would be quite erroneous to infer from this fact what might happen in very dilute solutions. I had therefore to devise a method which would not only admit of the detection of the reactions (double decomposition) in very dilute solutions, but this without the further addition of any chemical reagent, by which perhaps the conditions of the reaction might be altered. I found a method, although in a somewhat circuitous way, which answered my purpose, and has, moreover, the advantage of being applicable to the solution of the question of the mutual decomposition of salts—for instance, chloride of sodium and sulphate of magnesia, when in solution. This method is based upon diffusion, and the principle may be elucidated in the following manner: Let us suppose that we have a solution of a salt, of which it is premised that it is not altered by the chemical action of the water, and that this solution (without the aid of an intermediate membrane) is allowed to diffuse in pure water, by pouring a layer of water very gently upon the saline solution, and leaving the vessel containing the liquid to stand quietly. After some time layers, varying in thickness, will be formed, each containing variable quantities of the salt; but the relation between the acid and basis will be everywhere the same, since the salt is not decomposed. Let us now suppose that, at the outset, a second substance has been added to the saline solution, which exerts a decomposing action upon the salt, then in that case the new compounds, one of which contains the base, the other the acid, of the salt, will have a different capability of diffusion, and consequently after some time the two constituents of the salt, while forming layers of different thickness, will not be present in the constant relation of the equivalents, but in a more variable proportion. When the diffusion process is interrupted at the proper time, and the composition of the substances present in the different layers is determined by properly conducted chemical analysis, the results will prove whether a decomposition of the salt has taken place. As regards the objections which might be raised against the applicability of this method, these I shall fully answer in my large work on the subject. By the use of this method, I have succeeded in giving a definite answer as regards the decomposition of the alkaline nitrates; but I will adduce here only one of the many experiments I have made-I litre of solution, which contained, upon 200,000 c.c., I equiv. of oxalic acid and I equiv. of nitrate of potassa, was placed in a tall cylindrical-shaped glass vessel, and upon that solution 1 litre of pure water was cautiously poured, and left to diffuse for a period of four weeks, after which I analysed two portions of the fluid, viz., an upper and lower layer. If no decomposition had taken place, I should have found in both layers the equivalent proportions of potassa and nitric acid; I, however, found in the upper layer an excess of nitric acid greater than that corresponding to the potassa equivalent, and in the lower a negative deviation; hence it might be inferred that decomposition had really taken place, and, as a control for the accuracy of the analysis, it was evident that the positive and negative difference of the upper and lower layers ought to possess equal value within the limits of faults of experiments. The difference amountedIn the upper layer, to +0.20 In the lower layer, to -0.32 Taking into consideration the very small quantity of substance which, owing to the great degree of dilution of the liquid, could be operated upon, and also the difficulty of the estimation of nitric acid, and the constant influence of faults of experiments, by which the positive difference is lessened and the negative increased, I think a greater degree of agreement could hardly be expected than that just quoted; but, moreover, I made many similar experiplacements, and also corresponding ones with nitrate of soda. There can be, therefore, no doubt that the alkaline nitrates are in like manner decomposed, at least in part, by oxalic acid in very dilute solutions by the addition of oxalic acid. It is true that I have not yet quantitatively estimated the relative quantity of nitric acid which is set free, but it must be observed that almost insuperable difficulties exist in such an estimation. It is probable that the alkaline nitrates are only partly decomposed, and by no means so completely as the nitrate of lime, because all the products of the reaction remain in solution, so that consequently, according to the well-known principles of the chemical influence of masses, the liquid comes to a state of equilibrium with which every reaction ceases. By these researches we obtain some insight into a definite chemical process as it occurs in plants; we learn by what process the oxalate of lime so frequently met with in plants, and also the binoxalate of potassa, owe their origin, and we further find that the free nitric acid in the living plant is an active agent which plays a considerable part in the formation of the nitrogenous organic matters. Although it might be a pleasant field of further speculative discussion, I do not consider that we can enter more fully upon it so long as our knowledge of the first products of the reduction of carbonic acid are so scanty as at present. I think it very probable, however, that the nitric acid does not remain long unaltered, but is soon converted into either ammonia or hydroxylamine by the powerful reducing agency of the plants, while these last-named products in nascent state react upon the unequally nascent products of the reduction of carbonic acid, and thus together lead to the formation of organic nitrogenous compounds.Ber. d. Deutsch. Chem. Gesells. CORRESPONDENCE. been more strict to have said "above the upper end of the spectrum visible on the screen, in place of "above the violet end of the spectrum;" for though this seems to be A GENERAL INDEX TO THE VOLUMES OF the violet end, and is usually so called by lecturers, it is THE "CHEMICAL NEWS." not identical with what is strictly so named in other connections. Thus the lines shown in the lecture referred to, were the lines in that part of the violet not visible otherwise under the other conditions of the experiment, and not the extra violet lines. With glass prisms higher lines can be shown; and with two fine quartz prisms and a lens of the same substance, which we have in our collections, I have projected all the lines of the strictly actinic or invisible spectra of the metals used, but on account of the smaller dispersion of these substances, the experiment is much less effective than that made with bisulphide of carbon prisms as described. I am, &c., HENRY MORTON. Stevens Institute of Technology, Hoboken, New Jersey, Dec. 30, 1872. MISCELLANEOUS. Metropolitan Gas Supply.-The reports of the chief gas examiner, just presented to the Corporation of London and Metropolitan Board of Works, show the average quality and purity of the gas supplied during the past quarter by the three companies under his supervision,. as follows:Illuminating Sulphur. Ammonia. Grs. per 100 ft. Grs. per 100 ft Beckton power. Candles. 17:00 17.31 17.31 16.76 Pimlico (cannel) 24:25 SIR, I cannot see that Mr. Holland's paper is a very EXPERIENCE. FLUORESENCE AND THE VIOLET END OF A To the Editor of the Chemical News. SIR,-In reading over my article in your journal of Dec. 6, which has just arrived, it strikes me that some may be puzzled by a statement on page 273 unless a further explanation is made. It is well known that the bisulphide of carbon will only transmit rays of the spectrum as high as about 17° of the Bunsen scale, or a little above the line H', and it might therefore be asked how invisible lines could be shown on a fluorescent screen with bisulphide of carbon prisms. The fact is that even with a powerful electric light, so feeble is the illuminating power of the violet rays that nothing is visible on an ordinary screen, when a spectrum some 10 feet long is thrown much above 10 of the scale; while thallene, being strongly excited by rays even as low as 9 or F, turns the practically invisible violet lines into brilliant green ones. It would have Fulham 33972 South Metropolitan 16:24 Comptes Rendus Hebdomadaires des Séances de l'Academie des Nitrification of Garden-Mould.-J. B. J. D. Boussingault.This exhaustive monograph treats on the formation of nitre in the nitre-beds, and in arable and garden soils. Some Combinations in which Phosphorus Appears to be Present in an Allotropic State, similar to that of the so-called Red Phosphorus.-A. Gautier.-After referring to a suboxide of phosphorus, P,O, discovered in 1837 by Le Verrier, the author points out that there are several compounds of phosphorus, the real composition of which is not at present well known some of them being amorphous. The main portion of the essay is devoted to the description of a compound formed by the action of protochloride of phosphorus upon phosphorous acid when these substances are heated in sealed tubes to a temperature of about 170°; the result in this instance is the formation of amorphous phosphorus according to the formula3PC1+7PH9O3=4P+3P ̧H,O,+9HCl. When these substances are only heated to 79° the reaction is different, and there is formed a compound PHO according to the following formula: 11PC1+27PH2Og=4P ̧HO+11P2H2O,+33HCl. The body alluded to is yellow-coloured, amorphous, unaltered by exposure to dry air, insoluble in water, alcohol, ether, benzin, chloroform, oil of turpentine, glycerine, acetic acid, protochloride of phosphorus, and protochloride of antimony. The substance is very stable, and bears heating in a current of dry carbonic acid to 250°. At 265° some phosphuretted hydrogen is given off, and at 350° to 360° phosphorus distils over. When heated in contact with air, this body (P,HO) burns slowly; mixed with chlorate of potassa it detonates by the application of a smart blow. Dilute acids do not act upon it, but ordinary nitric acid gives rise to violent reaction. Water at 170° decomposes the compound with formation of pure phosphuretted hydrogen PH, and phosphorous as well as hypo-phosphorous acids. Alkalies decompose P,HO, which unites with ammonia. The author concludes his paper with some observations on Le Verrier's suboxide of phosphorus, which he thinks may be identical with the compound obtained by him (see Annales de Chimie et de Physique, 2nd series, vol. lxv., p. 257). Estimation of Ammonia in Illuminating Gas.-A. Houzeau. -The detailed description of a volumetric process, in which dilute sulphuric acid of known strength, and also an ammonia solution of definite strength, are applied; the gas is passed from the meter through the acid. According to the author the gas at Rouen was found to contain on an average o 1042 grm. of ammonia in 100 litres of gas, while the gas in Paris only contains o'009 grm. of ammonia in the same bulk. There are also several original papers relating to mathematicophysical and natural history sciences. Bulletin de l'Academie Royale des Sciences, des Lettres et de Beaux Journal für Gasbeleuchtung und Wasserversorgung, No. 23, 1872. The contents of this number relate only to gas- and water-works engineering. Revue Hebdomadaire de Chimie Scientifique et Industrielle, Bleaching Cotton, Flax, and Rags Intended for PaperMaking, &c., by Means of Ozone.-M. David.-The anthor ozonises air by passing it over a mixture of permanganate of potassa, peroxide of manganese, and sulphuric acid contained in large carboys. He then conveys the ozonised air into a brick tank, which contains the materials to be bleached. After some some hours' contact with the ozonised air they are all perfectly bleached and clean. the evolution of gas (C,H, and C,H,) simultaneously there is obtained CH2-CH, This investigation was instituted with the view of obtaining an alcohol, Iron Ore from Andorra.-H. Flobert.-It appears that the mineral resources of the country alluded to (the most ancient Republic of Europe) are beginning to attract attention. In addition to excellent qualities of fine marble, copper and lead ores, and useful mineral waters, there is abundance of excellent iron ore free from sulphur and phosphorus, and having, according to the author's analysis, the following percentical composition:-No. 1-Water, 7:24; peroxide of iron, 87 215; siliceous matter insoluble in acids, 3'103; manganese, 0'35; other matters (not specified) soluble in acids, 2 092; total, 100'00; percentage of metallic iron, 6150. No. 2-Water, 8.60; peroxide of iron, 74'13; insoluble in acid, 10'60; soluble in acid (not specified further), 6'495; manganese, o 165: total, 100'0; metallic iron, per cent, 519. Trade in Esparto Grass (Lygæum Spartum) of Algeria.Ch. Mène. This paper contains statistical and other interesting inormation on this subject. Lactate of Lime.-A. Petit.-When a solution of this salt is treated with phosphoric acid so as to form a decimal solution (solution audixieme) of lacto-phosphate of lime, there is formed a liquid which, when cold, is quite clear and free from any precipitate; but when hot, a precipitate is formed, which almost re-dissolves on cooling. This number further contains the following original essays and papers: Two Pentachlorides of Benzine.-E. Jungfleisch.-This lengthy essay is chiefly written to explain the objections made by Dr. Ladenburg, and published in a German scientific periodical, against the author's researches on this subject, which will be shortly published in extenso. It appears, however, that there is a difference of the action of pure cry chlorine upon benzine, and of that gas in wet state, which apparently has escaped Dr. Ladenburg's notice. Bulletin de la Société Chimique de Paris, December 15, 1872. From the proces-verbaux of the meetings of this Society, published in this number, we quote the following: Preparation of Di-Isopropyl. - R. D. Silva.-The author observes that Dr. Schorlemmer's statement concerning the inactivity of sodium upon the iodide of isopropyl is not quite correct, since the author found that decomposition ensues at from 120° to 130°. With Chlorhydrate of Narceine.-A. Petit.-This paper treats chiefly on the solubility of narceine, its chlorhydrates and their mode of preparation. Narceine is very soluble in caustic potassa solution (015 thereof dissolves 1 grm. of the alkaloid), and in caustic ammonia, which leaves the narceine, after evaporation, in crystalline state. Narceine is soluble in 769 parts of water; narceine + HCl in 277 parts of water; narceine + 2HCl in 150 parts; narceine + 3HCI in 130; narceine +4HIC in 50. On the Hydrates of the Monobasic Fatty Acids.-E. Grimaux. -This exhaustive monograph, elucidated by a large number of complex formulæ, is not well suited for abstraction. Polytechnisches Journal von Dr. E. M. Dingler, first number for December, 1872. New Method of Preparation of Caustic Soda.-W. Helbig. -The main gist of this paper relates to the oxidation of some sulphur compounds, present in the crude materials (the concentrated lye), by means of a forced current of air passed into the concentrated liquor instead of the use of saltpetre. From the account here giver, it appears that while the last-named salt cannot be quite dispensed with the quantity has been greatly decreased. Estimation of the Quantity of Juice Present in Beet-roots. -F. Jicinsky.-This essay, illustrated by woodcuts and elucidated by several tables, contains a detailed account of the best methods of estimating the quantity as well as the saccharine value of the juice of beet-roots. Priew's Steam-Clearcing Method.-Dr. Dingler.-This paper, also illustrated by engravings, contains the account of a newlydevised method of clearcing sugar by means of low-pressure steam and air mixed, instead of the use of a pure concentrated sugar solution. The process is carried on in connection with centrifugal machines. Application of Steam for the Purpose of Extinguishing Fires. Dr. H. Weidenbusch.-This essay treats exhaustively on the The application of steam for the purpose of extinguishing fires. author quotes several well known instances in which steam, superior in every respect to water, has been successfully used to arrest the spread of, and rapidly extinguish fires. Gas-Tight Impermeable and Indestructible Corks.-F. Ruschhaupt.-The process here described consists in soaking the corks in pure molten paraffin, whereby, according to the author, the corks are rendered perfectly impermeable to gases and a great many liquids (all those which do not act upon nor dissolve paraffin), while the corks are rendered to some extent indestructible. The American Journal of Science and Arts, December, 1872. In addition to a series of original papers relating to other physica sciences, this number contains the following original papers bearing upon chemistry: Note upon Aventurine Orthoclase Found at Ogden Mine, Sparta Township, Sussex Co., N.J.-Prof. Leeds.-After giving a geognostico-mineralogical description of this mineral, the author quotes the following chemical analysis per cent:-Silica, 64-81; alumina, 1902; ferric oxide, 0'23; lime, 126; magnesia, o'59; potassa, 14'30; loss by ignition, o'26. On Soil Analyses and their Utility.-E. W. Hilgard.-This paper has already appeared in full. On a Crystal of Andalusite from Delaware Co., Pa.-E. S. Dana.-Illustrated with woodcuts. Journal für Praktische Chemie, No. 16, 1872. This number contains the following original papers: Contribution to Our Knowledge of Diabase.-R. Senfter.This exhaustive monograph is an appendix to T. Petersen's researches on green stones (see CHEMICAL NEWS, vol. xxvi., p. 288), and is elucidated by a series of tables exhibiting the results of analyses of a large number of minerals. The main results of the author's investiga |