62 Organisation among Chemists. from the summit of which hung a thread ending with a heavy point. The base of the pyramid thus arranged was applied to the plane which was to be levelled, and carried over this plane in all directions. Wherever the plane ceased to be horizontal the joint deviated from the centre of the base. "The balance-clock consisted of a long lever suspended similarly to the balance-level. To one of its arms was attached a reservoir of water, which, by means of a small hole perforated on the bottom of it, emptied itself in twenty-four hours. This reservoir, being filled with water, was poised by weights attached to the other arm of the lever, and in proportion as the water flowed from it the arm bearing it was lifted, the weights on the other arm slid down, and by their distance from the centre of suspension indicated the time which had elapsed." Many points of interest, demanding at least a passing notice, may be embodied in a summary of the principal propositions contained in this treatise : 1. The "Book of the Balance of Wisdom shows the Arabian philosophers of the twelfth century to have entertained advanced views regarding attraction. They recognised gravity as a force, and attributed to it a direction towards the centre of the earth; they also knew that it diminishes with the distance, but they erroneously supposed this diminution to be in the direct ratio of the distance, and not as its square. 2. They were acquainted with the connection between the weight of the atmosphere and its increasing density, since mention is made of the loss of weight of a body weighed in a denser atmosphere. 3. They understood the theory of centre of gravity, and applied it to the investigation and construction of balance and steelyards. 4. They made frequent use of the hydrometer, which 5. They observed the action of capillary attraction. 7. Their system of philosophy was founded on experi ment and observation. In conclusion we quote the following appropriate remarks from M. Khanikoff's introduction: "The history of the sciences presents to us an incontestable fact of deep significance-the re-discovery in modern times of truths laboriously established of old; and this fact is of itself enough to indicate the necessity of searching carefully in the scientific heritage of the past after all that it may be able to furnish us for the increase of our actual knowledge; for a double discovery, necessarily requiring a double effort of human intellect, is an evident waste of that creative force which causes the advance of humanity in the glorious path of civili sation." CORRESPONDENCE. ORGANISATION AMONG CHEMISTS. To the Editor of the Chemical News. SIR, My letter to you of the 6th June last, published in the CHEMICAL NEWS (vol. xxxiii., p. 240), has led to some persons, interested in the establishment of the proposed Institute, addressing communications to me, in some cases seeking for information as to the details of the scheme and promising both moral and financial support, and in other cases making suggestions with a view to my clients' scheme being made more perfect in its details. CHEMICAL NEWS, In all cases I find a strong feeling prevailing amongst chemists of character and position as to the necessity for vigorous steps being taken to raise the status of persons adopting chemistry as a profession; and now that what has for a long time past seemed to be idle talk, or the dreams of visionaries, is assuming a form, and showing the elements of vitality, a lively interest is displayed by many who are desirous that as soon as practicable the Institute should be established and its important work commenced. Questions are, however, from time to time raised as to the persons to be admitted to membership, and the manner of their election. Your readers may rest assured that these questions have already received full consideration on the part of the active promoters of the scheme. The qualifications of the several classes of persons, and the conditions upon which they were to be received into the membership, as stated in my letter to you (CHEMICAL NEWS, vol. xxxiii., p. 240), were not agreed to before objections thereto had been anticipated, and in consultation between some of my clients and myself fully discussed. It was felt that under all circumstances the regulations upon this point recommended by my clients would in actual working prove to be conducive to the success of the Institute, and as valuable in promoting its objects as any that could be devised. It was not, however, expected that all chemists would at once accept this part of my clients' scheme, but although alterations therein have been suggested to me I still consider that my clients' proposals are the best, and when fully understood will prove the most acceptable. It is objected that inasmuch as all persons who have practised on their own account in the profession of a consulting or analytical chemist for a period of five years" are to be eligible for election without producing evidence of training and fitness or undergoing an examination to prove such fitness, that "high" and "low" ar.alysts and quacks will not be excluded from membership, and that the principal object of the Institute will thus be lost. To guard as far as practicable against the admission of incompetent or disreputable men it is intended that every person proposed for election should be nominated by five persons having personal aquaintance with the candidate, that his name and the names of his nominators (after being submitted to the Council), and the date of his election should be communicated by post to each member of the Institute fourteen days before the date of election, and that at the ballot four-fifths of the members present must vote in the candidate's favour to secure his election. If the members do their duty, and act in a spirit of high honour in the observance of these regulations it is thought that improper persons will be kept out of the Institute but should any such person become a member, the power of expelling therefrom, upon proof of unworthy conduct, will, if the members are true to the principles governing the Institute, be sufficient to ensure that all persons wearing the dignity of membership shall be honourable and trustworthy men. It has been suggested that "works"" chemists should be entitled to become candidates for election on the same conditions as persons "who have practised as chemists on their own account for at least five years," and consequently without affording the evidence of training and employment as proposed in my letter of the 6th of June last, under the heading, "As to persons not now employed as chemists." Works' chemists are in many cases highly trained, able, and conscientious men, and in such cases difficulty will not be experienced in their establishing their qualifications and fitness for admission into the Institute. But it is, I believe, an acknowledged fact that many "works"" chemists are ill trained, and, except as to their own particular branch of chemical manufacture, are, in many cases, ignorant of the simplest principles of chemistry as a science, and beyond the circle of their own employment are quite unknown, and certainly have no public (and, outside the scene of CHEMICAL NEWS,} August 11, 1876. Chemical Notices from Foreign Sources. heir employment, any scientific) reputation. The Instiute would undoubtedly suffer if all "works"" chemists were indiscriminately admitted to membership without producing evidence of training and subsequent employment. As in the varied walks in life the innocent are required to suffer for the guilty, so in the case of the Institute, the competent "works'" chemist will have to prove his distinction from the incompetent servant, but having done this the honour of membership will be more clearly brought out, and be more thoroughly appreciated. It is obvious that in practice it would be found impos sible for the Council of the Institute to enforce any rule requiring candidates "now practising as chemists on their own account" to bring evidence of their training and fitness, and the Council could not make selections amongst that class of persons, requiring some to bring such evidence and permitting others to come without it. They would place themselves in a most invidious position were they to attempt to do so. As it is understood the Chemical Society is now advised that it cannot alter, or add to, its name, or sanction the creation of an Institute which shall be an adjunct to the Society, and in fact form a part thereof, it is desirable that the question of the establishment and the government of the Institute should now be taken earnestly in hand, so that an unnecessary delay may not occur after the recess in making the organisation complete. I shall receive with much pleasure any suggestions from your readers upon this important and interesting subject. I am, &c., 63 ferment. The ferment which determines this transforma tion is of a diastasic nature. Difference of the Potential Presented, after Rupture of the Inductor Current, by the Isolated Extremities of an Open Induction Coil.-A mathematical paper, not suitable for abstraction. Reactions of Chlorine under the Influence of Porous Carbon.-M. Melsens.-With reference to the paper of M. Damoiseau, read at the last meeting of the carbon upon gases is already well known to physicists and Academy, the author urges that the influence of porous chemists. A New Butylic Glycol.-M. Milan-Nevole.-The author describes in this paper the products obtained by the oxidation of his glycol. Explanation of the Impressionability of the Blackened Discs of the Radiometer by the Aid of the Emission Theory, according to J. B. Biot.M. W. de Fonvielle.-J. B. Biot, in the third volume of his "Traité de Physique," explains how the luminous molecules cannot communicate their vis viva to reflecting surfaces. In fact, these latter exert a truly repulsive action upon those molecules which, not touching them, cannot produce upon them any percussion similar to that impressed by electric forces. The considerations developed by this illustrious physicist not being applicable to blackened discs, we understand that the rotation of the radiometer should be produced in such a direction that they may fly from the ray. Is it not curious to find that the emission theory has permitted us to some extent, as far back as 1816, to foresee the experiment of Mr. Crookes? The explanation of the phenomenon, if we admit M. Biot's starting-point, does not require any new reasoning. The effort lost in the change of direction of the luminous molewhich does not appear reconcilable with the law of the conservation of the quantity of movement. Nevertheless, we may reply to this objection that according to the theory internal ray performed upon the ray of light; for the direction of the axis of the luminous molecules has been CHEMICAL NOTICES FROM FOREIGN cules seems at first sight not to produce any effect, a result SOURCES. NOTE.-All degrees of temperature are Centigrade, unless otherwise of emission this quantity of motion is represented by an expressed. Comptes Rendus Hebdomadaires des Seances, de l'Acadenie des Sciences. No. 2, July 10, 1876. Note on a Communication by M. Sacc, entitled "On Panification in the United States, and on the Hop as a Ferment."-M. L. Pasteur.-The author maintains, in opposition to M. Sacc, that the hop does not contain a soluble alcoholic ferment. Objections to the Last Communication of M. Hirn on the Maximum Possible Repulsive Pressure of the Solar Rays.-M. A. Ledieu.-The author, like M. Hirn, admits the excellence of the application of the method of successive elimination to the study of the cause of motion in the radiometer of Mr. Crookes; but an erroneous employment of this method only introduces a new element of complication into a question so delicate in itself. The numbers 0.0004157 grm. and 0'0008314 grm., proposed by M. Hirn to represent the maximum possible repulsion of light per square metre, whether for a blackened surface or for one perfectly polished, have no acceptable signification. M. Hirn assumes that the speed of the impact of the molecules striking the discs is no other than the speed of light itself, whilst in the hypothetical collision in question we must evidently consider the vibratory speed of the said molecules. But this latter velocity has nothing in common with the rapidity of propagation of the light-waves. Experimental Researches on Magnetic Rotatory Polarisation (Third Part: Dispersion of the Planes of Polarisation of the Luminous Rays of Different Lengths of Waves;.-M. H. Becquerel.-Unsuitable for abstraction. Cellulosic Fermentation of Cane-Sugar.-M. E. Durin.-Cane sugar is split up into equivalent weights of cellulose and levulose under the influence of a special changed since the reflection, for in place of being situated in the direction of the ray these axes have become perpendicular to that direction after the reflection. In this hypothesis the energy destroyed is represented by that which has been employed for the polarisation of the incident ray. The author has studied, along with M. Ruhmkorff, an apparatus known in Germany under the name of light. mill-an appellation which seems to him scarcely justifi able, for the rotation of a wheel placed in the centre of a Geissler's tube seems exclusively produced by a dynamic effect peculiar to electricity, and in which light does not In fact, the vacuum is so imintervene in any manner. perfect that a radiometer placed in Geissler's tube cannot turn without the action of a ray of light. Further, the state of the surfaces has no influence upon the direction of rotation in Geissler's "mill," which is entirely bright, whilst the direction of this rotation is changed at will by altering the direction of the current. The preponderance of the negative flame, much more direct than the positive, cannot exert, as the author at first believed, any influence of being set in motion by the light from a smouldering on this inversion, for a very sensitive radiometer, capable match just blown out, was not moved by the light of an induction spark striking sufficiently near to the glass case to perforate it. Crystallisation of Sugar.-M. G. Fleurens.-The value of this paper lies in tables which cannot be abridged. Remarkable Case of the Reduction of Nitric Acid and the Oxidation of Acetic Acid with the Production of Alcohol under the Influence of certain Microzymas.-M. J. Béchamp.-The author controverts the view of M. Méhay that the decompositions in question are exclusively due to chemical reactions. BRASS AND IRONFOUunders, ST. HELEN'S FOUNDRY, LANCASHIre. Makers of every description of Chemical, Colliery, Copper Ore, Gold Mining and Glass Machinery, including Crown, German Sheet, and Plate Glass Plant, as supplied to some of the largest Firms in England, Ireland, Scotland, and Wales. Makers of the latest Improved Revolving Black Ash Furnace S. A. SADLER, CHEMICAL NEWS, Aug. 11, 1876. CLEVELAND CHEMICAL WORKS, MIDDLESBROUGH; Newfall Tar Works, Carlton; and Ammonia Works, Stockton-on-Tees. Manufacturer of Benzole, Toluole, Xylol, Solvent and Burning Naphthas, Carbolic Acid and Disinfecting Powder, Refined Anthracene, Naphthaline, Black Varnish, Refined Far, Crude Liquid Ammonia, Galvanising Salts, Coal-Tar, Pitch Creosote, Grease, &c., &c. S. A. S. is always a buyer of Coal-Tar Naphthas, Crude Anthracene, and all Tar Products. All communications to be addressed to the offices at Middlesbrough. SPENCE BROTHERS CHEMICAL Co., LIM., VICTORIA CHEMICAL WORKS, BRADFORD, MANCHESTER. Manufacturers of LIQUOR AMMONIA, SULPHATE of AMMONIA, VITRIOL, Brown and Rectified, ALUM CAKE, &c., &c. CHEMICAL LABORATORIES SUPPLIED WITH APPARATUS AND CHEMICALS OF THE BEST QUALITY AT THE LOWEST MARKET PRICES M. JACKSON, MANUFACTURER AND IMPORTER, WHOLESALE AND RETAIL 65, BARBICAN, LONDON. Catalogues on application. JOHN PAGE, (Late Page & Tibbs), 47, BLACKFRIARS ROAD, S.E., Continues to supply the Trade with Phosphorus, Chlorate of Potash Pure Acids, Pyrotechnic and all other Chemicals, Pure and Commercial at the Lowest Prices. SPECIAL QUOTATIONS ON APPLICATION. Plymouth Tar & Chemical Works, CATTEDOWN, PLYMOUTH. Rectified), Creosote, Lubricating Oils, Grease, Disinfecting BISULPHITE OF LIME. WILLIAM MARRIOTT, CHEMICAL WORKS, HUDDERSFIELD. with Siemens's Patent Gas Arrangement, and as used in the Manufac- JAMES WOOLLEY, SONS, & CO., ture of Soda. Improved Valveless Air Engines, and Pumps or Acid Forcing, Air Agitators, Compressors for Collieries, and Weldon's Patent Chlorine Process. Caustic, Chlorate, Decomposing, and Oxalic Pans. Gas Producers for Heating Furnaces. Pyrites Burners for Irish, Norwegian, and Spanish Ores. Retorts, Acid Gas, Nitre, Nitric Acid, and Vitriol Refining. Photographs, and other information, supplied on receipt of Orders. 69, MARKET STREET, MANCHESTER, DEALERS IN CHEMICAL AND SCIENTIFIC APPARATUS, CHEMICAL REAGENTS, &c., OR THE USE OF ANALYSTS, SCIENCE TEACHERS, AND MANUfacturers. Price Lists on application. By far the best method of estimating iron volumetrically is that by permanganate of potash, after previous reduction of the ferric to a ferrous compound. The difficulty encountered is how to perform this reduction in the best, quickest, and cheapest manner. The best and most complete method of reduction, according to my experience, is that by hydrogen, in a porcelain tube, at a red-heat. To make the reduction complete it is necessary to pass the gas over the heated ore for three hours. Not more than 0'3000 grm. of the ore should be taken, otherwise at the end of the time specified the reduction will be found to be incomplete. The ore is weighed out in platinum boats, four of which may be placed in the tube and reduced at once. The tube is allowed to cool while the hydrogen is still passing the boats, removed, and carefully dropped into flasks containing hot dilute sulphuric acid. The flasks are closed with doubly-perforated corks, and a current of hydrogen is passed into them while the iron is dissolving. When the solution is complete the flasks are plunged into cold water (hydrogen being still passed into them) and allowed to cool completely, and are then titrated in the usual way. Coal-gas cannot be used in place of the hydrogen, as some of its constituents dissolve in the hot acid and exercise a reducing action on the permanganate. With a great many ores, especially limonites, the reduced iron dissolves with great difficulty, sometimes not at all. This difficulty has been overcome by Dr. T. N. Drown, who passes oxygen or air over the heated ore for half an hour before reducing. The carbonaceous matter is in this way destroyed, and the reduced iron is found to dissolve with the greatest ease. In this modified form I know of no more elegant and accurate method of determining iron in its ores. Some results obtained at different times, on different ores, show the precision of the method. The numbers represent percentages of metallic iron. water, and an excess of stannous chloride run in from a lution was added, and iodine solution run in from another burette until the blue iodide of starch remained permanent. It was found best to have the iron solution rather concentrated and warm. One c.c. of the stannous chloride solution was equivalent to about o'0120 metallic iron and 3 c.c. of iodine solution. The stannous chloride worked best when freshly prepared. Ten determinations of iron in a limonite gave These results for technical purposes are as good as is necessary. Four of the samples were weighed, dissolved, reduced, and titrated in an hour and twenty minutes. In a second trial, with four more samples, the same time was taken. In both cases the solutions were standardised while the ore was dissolving. This gives an average of twenty minutes as required for one determination, which is all that could be desired. I find it best to standardise the stannous chloride solution by means of metallic iron. This is dissolved in hydrochloric acid and a few pieces of potassium chlorate added; after which the solution is evaporated nearly to dryness. By this means every trace of free chlorine seems to be expelled. A solution of ferric chloride, when freshly prepared, is reduced almost immediately upon addition of the stannous chloride. After standing some time, however, it is more slowly reduced, and seems to require less tin solution. A solution of ferric chloride which had been kept for some months, one volume of which by precipitation in a platinum dish by ammonium hydrate gave o°1024 and 0·1024 iron, when estimated by means of the tin solution gave results which are neither high enough nor closely agreeing. Lafayette College, June, 1876. 48.50 Average, 48.67 48.71. 48.78) Almost all the magnetites when dissolved in acid leave a residue containing iron. The iron in this residue is not reduced by the hydrogen when the iron is determined as above. In this respect, however, the process is neither better nor worse than those ordinarily used. There are only two valid objections against this method. The first is the gas consumed, which makes it costly. The second the time required-from four to six hours. In order to find a means of determining iron very rapidly, with a reasonable degree of accuracy, various processes have been tried, but thus far none have given better results than that by reduction of the hydrochloric solution of the ore by stannous chloride. The ore was dissolved in hydrochloric acid in a beaker, and evaporated nearly to dryness. The solution was then diluted with a little NEW FORM OF COMPENSATING PENDULUM. By J. LAWRENCE SMITH, Louisville, Ky IN the construction of this new form of compensating pendulum I have taken advantage of the very great expansibility of that combination of sulphur and caoutchouc known as vulcanite or ebonite. Its coefficient of expansion is known to approach that of mercury in the ranges of temperature from 0° to 70° C. The mechanical arrangement adopted is a very simple one. The rod of the pendulum is of round steel, with an adjusting screw at the lower end; a round rod of vulcanite with a hole in the centre is passed on to the steel rod, fitting it loosely, and being held in place by the adjusting screw. The bob of the pendulum consists of a heavy mass of brass, with a hole through the centre large enough to admit the vulcanite over which it passes, and, by a properly arranged stop, rests on the end of the vulcanite farthest from the lower end of the pendulum, so that any expansion of the vulcanite elevates the brass bob, thus compensating for the downward expansion of the steel rod and brass bob. There is a simple mechanical arrangement for adjusting, till 425° does the formation and volatilisation of chloride the proper difference between the length of the vulcanite of copper begin. The permanence and the efficacy of the and the other parts of the pendulum. sulphate of copper can be increased by the presence of certain salts inactive in themselves, such as the sulphates of potash and soda. For a second pendulum to an astronomical clock I have used the following dimensions :-Diameter of the steel rod, 6 m.m.; diameter of vulcanite, 25 m.m.; length of same, 165 m.m.; diameter of brass bob, 63 m.m.; length of the same, 156 m.m. These dimensions are in no way insisted on as being the best. For a half-second pendulum I have used a steel rod, 3 m.m. in diameter; vulcanite, II m.m. in diameter and 63 m.m. long; brass bob, 38 m.m. in diameter and 57 m.m. long. I have had one of these pendulums attached to an astronomical clock, and after adjustment it has been running four months with very satisfactory results. Should this form of pendulum prove itself constant and correct, it would certainly be a convenient one for transportation, and very much less costly than the ordinary form. And as for the half-second pendulum, in such constant use in mantle clocks, it will be of the greatest service, and not add more than 20 cents cost to the commonest form of pendulum that can be used. As regards the uniformity of the coefficient of expansion of all vulcanites, of course it is not to be supposed that it can be relied upon; but a very simple method is used to ascertain it for any single specimen, or for a number made of the same lot of material. I have made experiments on several different specimens, and the results vary little from each other. The range of temperature with which the experiments were made was from zero to 43° C., on a bar 25 m.m. in diameter, and 304 m.m. long, this expanding in length 9 to 10 m.m.; making the entire expansion equal to 1-126th of the entire length of the rod for a temperature ranging from freezingto boiling-point, giving as coefficient for linear expansion for 1° C. 0'000079365. This coefficient is seen to be lower that that of mercury: but from the fact that mercury corrects the pendulum by only one-half its expansion, and the vulcanite is made to correct it by its entire expansion, the length of vulcanite required is even less than the column of mercury used in the mercurial pendulum. This instrument is one whose use depends on its accuracy of operation after careful trial for some time.-American Journal of Science and Arts. REPORT ON THE DEVELOPMENT OF THE CHEMICAL ARTS (Continued from p. 55.) Chlorine, Bromine, Iodine, and Fluorine. By Dr. E. MYLIUS, of Ludwigshafen. DEACON observed that the decomposition between hydrochloric acid and oxygen takes place at a far lower temperature if the gaseous mixture, instead of passing simply through ignited tubes or over porous substances, is conducted over heated salts of copper, lead (except the sulphate), or compounds of manganese. The copper salts were found most effectual, so that when a mixture of hydrochloric acid with an excess of atmospheric air was passed over porous bodies saturated with sulphate of copper and heated to 370° to 400°, all the hydrochloric acid was burnt to chlorine and water. In this reaction, which begins at 260°, the sulphate of copper remains unchanged if the temperature is not raised too high. Not A number of experiments conducted by Deacon in concert with Hurter and Carey, since the year 1867, have led to a knowledge of the conditions of the reaction of air and hydrochloric acid in presence of salts of copper.* 1. The quantity of the hydrochloric acid decomposed by a molecule of copper sulphate in gaseous mixtures of similar composition at the same temperature depends on how often the gaseous molecules pass through the sphere of action of the copper salt. 2. At all speeds of the gaseous current in long tubes of the same section, the opportunity for action in one and the same time is invariable. 3. In long tubes of different sections the opportunity of action is equal when the velocities of the currents are inversely as the squares of the diameters of the tubes. 4. In porous masses the efficacy increases directly as the speed. 5. Other conditions being equal the quantity of hydrochloric acid decomposed varies as the square root of the number expressing the proportion of the hydrochloric acid and oxygen. 6. At very high temperatures a certain quantity of chloride of copper is formed, but its amount stands in no proportion to the chlorine liberated. 7. The efficacy of the copper salt extends to gas molecules not in contact with the salts; the decomposition of the hydrochloric acid takes place, therefore, under conditions in which a material exchange between the copper salt on the one hand and the hydrochloric acid and air on the other cannot take place. Without entering upon the experiments made to explain the efficacy of the copper salt we turn to the method of the practical execution of Deacon's process as hitherto carried out. The hydrochloric acid is either prepared from salt and sulphuric acid in a common salt-cake furnace or from previously prepared aqueous hydrochloric acid. On a small scale the latter is preferable, as in this manner it is easy to produce a current of hydrochloric acid of always equal strength, whilst the evolution of hydrochloric acid in the preparation of salt cake is very rapid at first, and subsequently becomes slow. On the large scale this difficulty is met by allowing several salt-cake furnaces to work in a series, so that when the evolution slackens in one, the activity of the next commences. The gas obtained in one or other manner is at once mixed with a quantity of air containing more oxygen than suffices to convert all the hydrochloric acid into chlorine. It is then conducted through heated U-tubes of cast-iron, which communicate to it the temperature required for the process. The composition of the gaseous mixture can be regulated at any moment by a small air-pump which, at every piston stroke, drives a certain volume of gas through a standard solution of soda coloured with litmus. From the heated tubes the gaseous mixture passes downwards into an almost cubical tower whose interior is filled with wall-stones arranged like a grating, and whose sides are traversed by flues, which keep up the temperature favourable for the process. The heat here, as in all other parts of the apparatus, is regulated by metallic pyrometers. The tower fitted up with stone blocks (the Regulator) serves to take up the excess of heat from the gaseous mixture, if the temperature has been carried too high, or to impart heat to it if the proper degree has not been reached. Recently, however, Deacon considers the regulator as unnecessary. (To be continued) "Berichte über die Entwickelung der Chemischen Indurtr'e Illustrating some Principles of Chemical Dynamics." Chem. Soc. Henry Deacon. "On Deacon's Method of Obtaining Chlorine Während des Letzten Jahrzenends." Journ., 1872, 725. |