12 Development of the Chemical Arts: I also found that it was immaterial whether the standard was added before the sulphuretted hydrogen water or vice versa. Thus there is no need, if the colour of the standard be too light, to prepare a fresh standard, as must be done in Nesslerising. It is only necessary to add another measured quantity to the liquid which already contains sulphuretted hydrogen. The addition of one or two drops of dilute hydrochloric or nitric acid in no way affected the accuracy or delicacy of the estimation of copper. In the case of lead, a drop of hydrochloric acid caused a faint turbidity (especially in estimating large quantities of the metal), which interfered materially with the results. If an acid must be added, When working with 50 c.c. of liquid, so small a quantity as 0.5 m.grm. of copper, or I m.grm. of lead per litre, may be estimated by this process. If it is required to estimate smaller quantities than these, the liquid must be concentrated by evaporation. If the amount of copper exceed 20 m.grms., or of lead exceed 10 m.grms. per litre, a smaller quantity of the liquid than 50 c.c. must be used. acetic acid is, I think, the best. THESE new fields of beautiful iron ore are situated partly in the Verchni-Dnieprovsky district of the Ekaterinoslaw Government, partly in the Elizavetgradsky district of the Cherson Government; iron ore is found here on the rivers Saksagane and Ingouletz, near the village Krivoy-Rog. About twelve miles from this place on the river Saksagane, near the village Tchervonnaia-Balka, large quantities of red hematite are found. Immense layers of hematite, 100 feet thick, are situated near the river Ingouletz and the village Doubovaia-Balka. The best layers of iron ore are the following: 1. On the left side of Ingouletz and on the right of Saksagane between the villages Krivoy-Rog and Doubovaia-Balka is a layer of ironstone 120 feet thick; the results of the analyses are: REPORT ON THE {CHEMICAL NEWS, Jan. 1876. PERHAPS Mr. E. H. Thiellay has unintentionally become which may have worthier applications in the future. the founder of a manufacture of peroxide of hydrogen Perhaps he may not be the first or the only hair-bleacher, Schrötter revealed to the public was previously known as appears from the following document. What von Schering, of the Council of Commerce, dated Berlin, July to the initiated. Thus it appears from a letter of M. 3, 1874, in which occurs the following passage :"The bleaching of hair, feathers, &c., by means of peroxide of hydrogen has been found practicable, the greatest difficulty being the ready decomposability of the material. In England and France it is prepared and sold for this purpose in quantity under the names Golden Hair Water' and' Auricome.' In my establishment it is often enquired after for the same purpose." Mr. J. Williams, of the firm Hopkin and Williams, of London, makes a similar statement in letters of July 20 and 27, 1874. By peculiar precautions, however, he is able to prepare permanent solutions of peroxide of hydrogen containing 10 to 20 volumes of available oxygen (3 to 6 per cent by weight of H2O2). The weaker solution, which is said to keep for months without change, is sold at 8s. per kilo., in larger quantities at 6s. The stronger solution is sold at double the price. The amount of oxygen in Thiellay's solution, as determined in the Berlin laboratory, agrees tolerably closely with the weaker of these preparations, and this may possibly be its true origin. As the bottle when the determination was made had been opened four weeks previously; as it was only half full and was merely provided with a common cork, the permanence of the solution may be considered sufficient for most purposes. Peroxide of hydrogen would not be the first body whose industrial application commenced with trifles and gradually reached an unimagined extension. Nitrate of silver served first the vanity of the world as a hair-dye long before its applications in photography. Schrötter* very rightly expresses the wish that peroxide of hydrogen might be generally accessible at a moderate price. Böttger, and previously Geiger, recommend its introduction into the pharmacopoeia. That for medicinal purposes it is preferable to oxygen, ozone, or ozonewater (!) is manifest. Whilst ozone only bleaches ivory in the strongest sunshine of summer, there is no doubt but that peroxide of hydrogen would answer the same purpose even in the absence of light. Progress in the Artificial Production of Cold and Ice. By Dr. H. MEIDINGER, Professor in Carlsruhe. Concentrated cold in the form of ice acquires day by day a higher importance for industrial as well as for domestic purposes. Brewing on the Bavarian system, the preparation of "Lager-beer," which, amongst us in Germany at least, has nearly superseded all other kinds of beer, depends upon the prolonged maintenance of a temperature bordering upon freezing-point. The confectioner has no other practical means of producing a degree of cold from -12° to -18°, as required in the preparation of ice-creams. The physician often employs the cold of "Berichte über die Entwickelung der Chemischen Industrie Während des Letzten Jahrzehends." + Von Schrötter, see above. Böttger, Polytech. Not zblatt., 1873, 13. Geiger, Lehrbuch der Pharmacie aufl. bearb., v. Liebig, i., 213. ice both externally and internally as an absolutely indis- | pensable remedy. The butcher and the hotel-keeper can scarcely dispense with this means of preserving meat. In the domestic sphere ice has become formally established, at least in large cities, where it can always be obtained at a cheap rate, and to those who have become accustomed to its use it appears a necessary agent for preserving food and cooling beverages during the warm season. In chemical manufactures ice has also found various applications in the crystallisation of salts, or, to speak in more general terms, in the separation of dissolved substances by means of cold. In proportion to the growing consumption we see increasing quantities of ice stored up every winter. An extensive system of transportation has been arranged for conveying ice from the more northern and colder parts of the earth to regions nearer the equator. North America especially ships ice in astonishing quantities in all directions, even to Central and South America, to the West Indies, and to India. Ice from Norway is sent to England and the German ports on the North Sea. In mild seasons, such as 1862-63 and 1872-73, ice from the glaciers of the Alps was sent down the Rhine in entire trains. Science has shown, however, how to prepare this important requisite artificially. The first attempts at the manufacture of ice on the large scale took place between 1850-60; but this branch of industry has since been much extended. Even in regions where the winter is, as a rule, cold enough to permit ice to be stored up in quantity, e.g., in Germany, it has often been found remunerative to construct machinery for its artificial preparation, or, in general terms, for the production of cold. Manufacturing establishments of this kind may be seen in various places in full activity, and after the mild winter of 187273 the demand for machine-made ice could scarcely be met. The London Exhibition of 1862 introduced the ether and ammonia ice machines. A third system has since been added, the air ice machine, which has not yet reached perfection, since peculiar difficulties interfere with its practical execution. The theories of these machines have been already explained, so that there is no difference of opinion as to their capabilities and their relative merits. A series of proposals have also been made for the production of cold by other agencies, which have hitherto produced little or no practical result. We will endeavour to descsibe the development which the question has taken in all its branches down to the present day. (To be continued.) THE ROYAL SOCIETY. order. The subject covers a large area, and is calculated to lead the investigator to the consideration of the most important chemical problems. "The memoirs of Dr. Hofmann in reference to the organic bases fall under several heads :-(1) The researches on Aniline and the Organic Bases contained in Coal-tar. These researches are mainly included in the period between 1843 and 1850. (2) The investigations on the molecular constitution of the organic bases derived by the substitution of the Alcohol radicals in the molecule of Ammonia (1850-51). (3) The Phosphorus Bases and the Diatomic Ammonias (1857-60). (4) The investigations on Rosaniline and the various Colouring-matters derived from Coal-tar (1860-70). "In the course of the aniline investigations Hofmann made an important contribution to the unitary theory of chemistry. Dumas had shown that the essential chemical properties of acetic acid were not altered by the substitution in the acid-molecule of chlorine for hydrogen; but no organic base had yet been discovered derived from another base by a similar process. Fritsche, indeed, had made a bromine derivation of aniline, in which three atoms of hydrogen were replaced by bromine; but the substance thus formed was a neutral (not basic) body. It occurred to Hofmann that the substitution had here gone too far, and that for this reason the basic properties of aniline had disappeared. Consequently, by an ingenious process (devised for the experiment), the treatment of chlorisatin by the hydrate of potash, he prepared mono-chlor-aniline-aniline, that is, in which one atom of hydrogen was replaced by chlorine. This body was a base, like aniline itself. Hofmann established its basic character by the preparation of many of its salts (Liebig's Annalen, vol. liii., p. 1, 1845). "At the date when Hofmann's paper on the molecular constitution of the volatile organic bases was presented to the Royal Society (December, 1849), Wurtz had just prepared, by a striking experiment, the primary monamines of the alcohol radicals-that is, a system of bases in which one-third of the hydrogen of the ammonia was replaced by the hydrocarbon, the existence of which (it may be noticed) had been predicted by Liebig as a consequence of his views as to the composition of the organic bases. The experiments of Hofmann were in the same direction as those of Wurtz, but of far more general application. By the action of the iodides of the alcohol radicals upon ammonia, Hofmann replaced successively the three atoms of hydrogen which its molecule contains by these hydrocarbons-a method fraught with important results, both theoretical and practical, with which all chemists are familiar. "Among other consequences, this method placed the theory of types on a solid experimental foundation, which AWARD OF MEDALS TO DR. HOFMANN AND served as the basis of its future development. A critical MR. CROOKES. IN presenting the Copley Medal to Dr. Hofmann and a Royal Medal to Mr. Crookes at the Anniversary Meeting of the Royal Society, November 30, 1875, Dr. Hooker, the President, said : "The Copley Medal has been awarded to Professor August Wilhelm Hofmann, F.R.S., of Berlin, for his numerous contributions to the science of chemistry, and especially for his Researches on the Derivatives of Ammonia. "The researches of Dr. A. W. Hofmann, from first to last, are related by a strict logical connection, from which (although in various side-paths he has made truly interesting discoveries) he has never essentially deviated. Indeed these researches may be considered as constituting one great and prolonged research on the organic bases theoretically and experimentally considered. It is not, however, to be imagined that because, to a certain extent, limited in its range, this work is of a special or technical test was given by which the constitution of any given "ammonia" could be ascertained, the number of derivatives of the "ammonia" when subjected to the action of iodide of ethyl corresponding to the number of atoms of hydrogen which it still retained unreplaced by hydrocarbon. Hofmann applied this test to aniline, and demonstrated, by the successive formation of ethyl-aniline and diethyl-aniline, that this base belonged to the primary monamine class, containing two atoms of hydrogen unreplaced by hydrocarbon. To trace out, however slightly, the consequences of this method would be a serious task indeed. It is sufficient to say that the views at present held by chemists as to the molecular constitution of water, according to which water is regarded, like ammonia, as a typical molecule, but containing two atoms of hydrogen (instead of, as in the other case, three) replaceable by the alcohol radicals, are based upon experimental evidence for which the very same instrument of research, the iodide of ethyl, and methods in all respects analogous to those by which Hofmann thus established the constitution of aniline were employed. According to these views triethyl-aniline represented 14 Award of Medals to Dr. Hofmann and Mr. Crookes. { ammonia in which all possible substitutions of this order | had been effected. However, Hofmann applied his test to this substance, and obtained a most remarkable result. A molecule of iodide of ethyl combines with a molecule of this substance, giving rise to the iodide of a molecular group, behaving like potassium or sodium, "a true organic metal in all its bearings." The ground of this assertion is, that this iodide of tetrethyl-ammonium, when treated with freshly precipitated oxide of silver, is decomposed with the formation of an oxide of the "organic metal possessing the main features of potash. This train of investigation has not as yet been adequately pursued; but the fundamental importance of this experiment, in reference to our knowledge of the elemental bodies, cannot be doubted. CHEMICAL NEWS, Jan. 14, 1876. The element had as yet been found in extremely small quantities only; but yet he was able to prove chemically as well as optically that it was a new substance, which, from some of its reactions, he thought most probably belonged to the sulphur group of elements, and to which he gave the name thallium. The investigation of this new substance was eagerly followed out; and by inquiries in various directions he succeeded in obtaining it in larger quantities, though his supply was still most inconveniently small, rendering it necessary to work the same material over and over again, instead of carrying on the investigation of two or more of its compounds simultaneously. This investigation, which had led him to perceive that the new body was a metal, which he isolated, was in progress when (in the summer of 1862) he was induced to send in a preliminary notice of his investigations to the Royal Society, instead of waiting, as he had intended, till the research was complete, in consequence of the publication by M. Lamy (who had been fortunate enough to meet with a comparatively fertile source of the new substance) of a paper in which he described several of its compounds and announced its metallic nature. The complete memoir was presented to the Royal Society early in 1863, and is published in the Philosophical Transactions for that year. It contains, among other things, a provisional determination of the atomic weight, giving a mean result of 203·96. "The first memoir on the phosphorus bases, in which the existence of a class of phosphorus bases analogous to the compound ammonias was experimentally established, was published in conjunction with M. Cahours. In three subsequent memoirs these compounds were further investigated with the determination of the differences by which they were discriminated from their nitrogen analogues. We have here presented to us the first example of a diatomic base formed by the action of bromide of ethylene or triethyl-phosphine, in which reaction (as in the similar case of the diatomic alcohols) Hofmann successfully established the formation of an intermediate monatomic bromide, the reaction taking place by two "The atomic weight of an element being a constant of distinct stages. In the third of these memoirs a new fundamental importance, Mr. Crookes spared no pains in class of compound bases is brought before us, containing an accurate determination of that of thallium. This both nitrogen and phosphorus. Subsequently, in a series research, which extended over several years, is described of somewhat less elaborate memoirs, the conception of in a highly elaborate memoir which was presented to the the typical character of ammonia is greatly expanded by Royal Society in 1872, and is published in the Philothe examination of the derivatives of two and three sophical Transactions for the following year. The various molecules of ammonia. weighings which the investigations required were per"As to the researches in reference to the colouring-formed and reduced with the most scrupulous regard to matter derived from coal-tar, it is only necessary to minute accuracy, as the utmost care was taken in the observe that his inquiries initiated and rendered possible preparation of the chemicals. Though only one method what is now a vast branch of industry. In reference to was employed, namely that of determining the weight of rosaniline itself (the key of the system), he established nitrate of thallium obtained from a known weight of the the fact, long unknown, that this substance was not an metal, the care with which the whole process was conaniline compound at all, but derived from the combina- ducted, and the near agreement of the different experition of aniline with toluidine. ments, are such as to lead us to regard the final mean 203 642 as most probably very near the truth. "I may lastly mention, as a fitting conclusion to this series of discoveries, an investigation of very wide interest, which has resulted in the construction of the normal cyanides (a) of the monatomic hydrocarbons, formed by the action of chloroform on the primary monamines, which, together with water, are resolved into formic acid and the base whence they are derived; while their isomers (class B), the nitrites, under similar conditions yield ammonia and their corresponding acids. Hofmann has also established the existence of a new class of cyanates (B) of the same monatomic hydrocarbons which, together with water, are resolved into ammonia and their corresponding alcohols, the original class (a) being resolved under the same circumstances into carbonic acid and the primary monamines, as in the experiment of Wurtz before referred to, the whole investigation standing in intimate connection with Hofmann's previous work. "To estimate the value of these results it is necessary to go through the vast mass of experimental evidence from which they are deduced, which constitutes a body of complete and exact information in reference to one general subject not easily paralleled in the history of chemistry. "A Royal Medal has been awarded to Mr. William Crookes, F.R.S., for his various chemical and physical researches, more especially for his discovery of thallium, his investigation of its compounds, and determination of its atomic weight; and for his discovery of the repulsion referable to radiation. "In the year 1861 Mr. Crookes communicated the discovery of a new element, which he had detected by means of a green line exhibited in the spectrum of certain selenium residues which he was examining for tellurium. "In the course of the weighings which were executed in this research, Mr. Crookes noticed some minute anomalies depending on temperature which did not seem referable to currents of convection. This led him into a train of experimental research which resulted in the discovery of an action of radiation, which, whatever be its real nature (a point still involved in mystery) and whether the action be direct or indirect, all who have seen or followed the experiments must allow to be most remarkable. An account of this research was published in the Philosophical Transactions for 1874. "When delicate beams of straw and other materials, carrying pith balls or disks at their ends, were mounted so as to turn as freely as possible within glass vessels from which the air could be exhausted, it was found that at atmospheric pressure the approach of a hot body produced a movement usually indicative of an attraction, real or apparent, between the ball and the body, and that of a cold body a reverse movement. In these motions, however, it is evident that currents of convection play a leading part; nor does it appear by any means certain that the actions may not be due to these and other wellknown causes. The same thing continues when the air is partially exhausted, until, at a certain high rarefaction varying according to circumstances, the motions cease, or nearly so. But on passing this, a new and unexpected phenomenon is revealed, which is exhibited in perfection in chemical vacua, and in the best vacua produced by the Sprengel pump with the improvements which Mr. Crookes has introduced into it. The suspended body is now repelled with striking energy when a source of radiant heat or light is presented to it, or even, if the radiation be powerful, when it is held at some distance, or when the sun's rays concentrated by a lens are thrown upon it. The action has more recently been exhibited by Mr. Crookes in an exceedingly striking form by means of a horizontal four-armed fly delicately mounted on a sharp point, and carrying at the ends of the arms pith disks in vertical planes passing through the arms, the disks being blackened on one face, on the same side for all. The motion depends in this case on a differential action on the black and white faces, the black being repelled. "It is the mystery attending this phenomenon that gives it its great importance. There is evidently some action going on with which we are not at present acquainted; and there is no saying what a thorough investigation into the cause of the phenomenon may lead to." PROCEEDINGS OF SOCIETIES. MANCHESTER LITERARY AND PHILOSOPHICAL SOCIETY. Ordinary Meeting, December 14th, 1875. EDWARD SCHUNCK, Ph.D., F.R.S. &c., President, in the Chair. PROF. SCHORLEMMER exhibited a sample of peat from lagoons in the Sierra Madre, in Mexico. It is very dense and not readily inflammable, giving very little flame, but when once red-hot it burns completely, without requiring much draught, to a perfectly white ash containing much calcium carbonate and a little sodium sulphide, which is derived from glauber salt which the peat contains. "Chemical Notes," by M. M. PATTISON MUIR, F.R.S.E., Assistant Lecturer on Chemistry, Owens College. I. On the Solubility of Potassium Perchlorate in Water. Having a small quantity of pure potassium perchlorate at my disposal, I thought it might be interesting to determine the solubility of this salt in water at different temperatures. The apparatus employed was similar to that described by Hannay (Journ. Chem. Soc. [2], xii., 203). The salt was placed in a small test-tube to which a thermometer was strapped, the whole being surrounded with ice or water maintained at the proper temperature. The following were the results obtained : A. Temperature o° C. Weight of liquid in the bulb, 4722 grms. Weight of bulb itself, 5·3954 grms. Hence the specific gravity of an aqueous solution of this salt saturated at o° equals 1'0005; the percentage of salt in solution is o'705; and the solubility of the salt is I part in 142'9 parts of water. B. Temperature 25° C. Weight of liquid in bulb, 4'7418 grms. Weight of residue on evaporation, o'0907 grm. Specific gravity of aqueous solution saturated at 25°, Percentage of salt in solution, 192. Solubility, I part in 52'5 parts of water. C. Temperature 50° C. Weight of liquid in bulb, 4'798. Weight of residue on evaporation, o 243. Specific gravity of aqueous solution saturated at 50°, Percentage of salt in solution, 5:07. Solubility, I part in 15.5 parts of water. D. Temperature 100° C. Weight of liquid in bulb, 4'9965. Weight of residue on evaporation, o'7870. Specific gravity of aqueous solution saturated at 100°, Percentage of salt in solution, 15'76. For each rise of 25° the solubility and the percentage of salt in solution increase in round numbers threefold. I may add that I found Hannay's apparatus exceedingly accurate and serviceable. II. On Basic Bismuth Perchlorate. If metallic bismuth be heated with an aqueous solution of perchloric acid, it is slowly converted into a white nonThis substance is insoluble in water: crystalline mass. when thoroughly washed and dried between folds of blotting-paper it presents the appearance of a bulky, pure white powder which it is difficult to obtain equally divided as the particles tend to gather together and form small more or less compact masses. This substance yields the following numbers on analysis: (a) o'3640 grm. Igave o 2675 grm. Bi2O3 =0'2382 grm. Bi. 0.2980 (b) 0.4173 =0'2670", (c) 0'4500 0'3231 =0'2900 Calculated for BIO.CIO.. Found: 64'52 .. 65'44 63'98 64'44 These numbers agree very well with those required by the formula BiO.C104, or it may be written Bi(ClO4)3.BizO3. Basic bismuth perchlorate is almost perfectly insoluble in water even at 100°: it is very readily dissolved by hydro 16 Simple Relation among the Elements. chloric or nitric acid; less readily by sulphuric acid; at a red-heat it is decomposed with formation of bismuth chloride which is slowly volatilised. III. On the Amount of Carbon Dioxide in the Air of SeaCoast Places. Thorpe (Fourn. Chem. Soc. [2], v., 189) has shown that the air over the ocean contains less carbon dioxide than air over the land, the mean numbers being 30 and 404 vols. per 10,000 of air respectively. During the long vacation I interested myself with a few experiments upon the air of the sea-coast, with a view to determine whether it inclined, as regards carbon dioxide, to sea air or to land air. The samples of air were collected at Ardrossan, a small town on the Firth of Clyde, where the river is almost entirely merged in the open sea. The estimations were conducted in accordance with Pettenkofer's method. The air of such a place as Ardrossan, although it be situated almost in the open sea, is not therefore influenced by the sea, so far as the carbon dioxide is concerned, but contains almost the same amount of that gas as is found in land air. To the Editor of the Chemical News. SIR,-In my "Note on the Chalybeate Water at Sellafield, near Whitehaven" (CHEMICAL NEWS, vol. xxxii., p. 309), I regret to find that I have made an error in copying the analysis of the clayey earth (therein alluded to) from my laboratory notes. I will therefore thank you to kindly give publicity to this letter, as a correction. The tabular analysis of the 'clayey earth" should have read as follows, as it appears in my notes taken at the time of analysing: Silica Alumina Ferrous oxide 40'24 38.62 10'73 0'70 2'00 5'30 2'05 0.36 100'00 CORRESPONDENCE. "IN ABSENTIA" DEGREES. To the Editor of the Chemical News. SIR, Some attention having been recently directed to the importance of judging men rather by what comes before than by the letters which follow their names, it may pos sibly interest some of your readers to know that even in the matter of degrees-whilst some men "achieve greatness," others have "greatness thrust upon them." About five years ago I wrote to an individual who advertised himself as willing to assist gentlemen in obtaining Ph.D. and other distinctions in absentia, asking him to give me some particulars of this mysterious process, and was informed that for a small fee "a suitable Literary petition in Latin would be written and submitted, with my biography, &c., and his best recommendations to the Senatus Academicus of any University I might select." My curiosity having been satisfied, I did not reply to this or any subsequent communication, but since that date Dr. has been one of my most constant and disinterested correspondents. I have now in my possession twenty-eight letters, circulars, cards, &c. (the last to hand a few mornings since), and many others have been accidentally destroyed. In one of these he takes considerable pains to explain to me, a countryman, the exact situation of his abode, that I may have no difficulty in consulting the oracle. In another he says-" Next week being Whit week I have no doubt you will be in London; please call on me." In another I am informed that, since he last wrote, the Deans of several Colleges and Universities have sent to several gentlemen their diplomas, and they are much pleased with them, as they are very handsome documents." Having waited long enough for the vision of these "handsome documents" to produce a due effect on my mind, he wrote “ I have the honour to inform you that the Senatus Academicus of the University (sic) has instructed me to state that the degree you applied for will be granted you on receipt of the fees." This overwhelming condescension on the part of the "Senatus Academicus" not meeting with a suitably eager and grateful response, he again wrote-" I am afraid, from your silence, that the fees are the obstacle to your promotion, and, as I am very anxious that you should receive your degree at once, I pray you to express to me, in confidence, the arrangement you would desire." No comment on the -I am, &c., Braystones, near Whitehaven, January 11, 1876. WILLIAM H. WATSON. PEROXIDE OF HYDROGEN AS A HAIR DYE, OR BLEACHER. To the Editor of the Chemical News. SIR, In the admirable "Report on the Development of the Chemical Arts during the last ten years," by Professor Hofmann, he states, in your inpression of the 7th inst. (CHEMICAL NEWS, vol. xxxiii., p. 3), that the expensive liquid used to impart a golden hue to the hair was, with respect to its composition, a secret until 1874, when Schrötter analysed it and proved it to be a solution of peroxide of hydrogen. In my Report on Public Health (Dublin Medical Journal, November, 1869), I stated that a specimen of colourless fluid, used at the present time for the purpose of giving dark hair the fashionable, i.e., yellow colour, was submitted to us for analysis. Very much to our surprise we found it to consist solely of solution of peroxide of hydrogen, or oxygenated water. Curiously enough, chlorine, instead of bleaching hair, rather darkens its hue." In my "Manual of Public Health," page 249, I give a formula for a yellow dye (H2O2) for the hair. My discovery in 1857, that urea is as effective as ammonia in furnishing nitrogen to plants, has not prevented one French and two German chemists I am, &c., from making the same discovery in later years.— CHARLES A. CAMERON. Royal College of Surgeons, Dublin, PERIODIC LAW SHOWING EXISTENCE OF A SIMPLE RELATION AMONG THE ELEMENTS. To the Editor of the Chemical News. SIR,-With reference to the paper by M. Mendeleeff, translated from the Comptes Rendus of November 22nd 1875, which appeared in the CHEMICAL NEWS, vol. xxxii., p. 293, I have to make the following remarks: |