An Investigation of the Air-Flow Pattern in the Wake of an Aerofoil of Finite Span, by A, FAGE AND L. G. F. SIMMONS. Communicated by Prof. L. Bairstow, F.R.S. The present paper gives an account of some experiments conducted with the object of determining the distribution of velocity in the wake of an aerofoil of finite span. The work of earlier experimenters shows the existence of a longtitudinal vortex system extending across the span from tip to tip; and the results of the velocity measurements over four transverse planes, three behind and one forward of the aerofoil, here given, provide further information on this subject. An analysis of the results shows that the vorticity is distributed over an area forming a band roughly parallel to the plane and ending in regions approximately opposite the tips, where the intensity is high. Further behind the aerofoil, the band disappears from the central part, and at about 13 chords away, the vortex system resolves itself into two localised areas. Integration over transverse planes 0.57 and 2.0 chords behind the aerofoil shows that the total strength of vorticity leaving a semi-span of the aerofoil is equal to the circulation around the median section; and further, that the distribution of vorticity in these planes is closely connected with the distribution of lift along the span. At 13 chords behind, it was found that the total strength of the vorticity is about 82 per cent. of that measured at 0.57 chords behind. In front of the aerofoil, and beyond each wing tip, the flow is shown to be irrotational. Over each of the planes of exploration behind the aerofoil, the velocity is sensibly uniform, and this allows the flow pattern to be represented, in the conventional manner, by contoure of the streamline function 1. . The Photo-active Constituent in Wet Bromine. Part II. The Kinetics of the Reaction and the Light Absorption of Wet and Dry Bromine, by B. LEWIS AND E. K. RIDEAL. The Budde effect in bromine is shown to be proportional to both the partial pressure of bromine and water vapour pressures, and is probably due to a photoactive This is bromine hydrate, Br2,H2O. strongly adsorbed by glass surfaces and the relationship between the concentration in the bulk and surface phases can be expressed in the form of an adsorption isotherm. The hydrate may be displaced from glass surfaces by water. The Budde effect is not produced by illumination of moist bromine with light or wave length longer than λ = 5800 A. The heat of formation of bromine hydrate is found to be 1090 calories comparable to the heat of solution of liquid bromine in water, whilst the equilibrium constant for the dissociation of bromine hydrate at 313° K is of the order of 3.10 × 10". The adsorption curves of wet and dry bromine have been compared, and it is found that absorption commences at λ 6100 A for the wet and λ= 5700 A for the dry gas; this corresponds with a lowering of the critical energy increment of excitation of 3400 calories. When corrected for the absorption and probably flourescent of dry bromine, it is found that the Stark-Einstein law of photo-equivalence is obeyed, a maximum of 1.35 quanta per molecule being obtained. = The Influence of Carbon Rings on the Velocity of Reactions involving their SideChains. Part I. The Hydrolysis of Cylic and Open-Chain Malonic Esters, by R. GANE AND C. K. INGOLD. Previous experiments, mainly based on ring formation, have shown that the angle between two of the valencies of a carbon atom may be altered by structural conditions relating to the other two. The Density of Boric Oxide Glass and the Suspected Variation in the Atomic Weight of Boron, by H. V. A. BRISCOE, P. L. ROBINSON, AND G. E. STEPHENSON. Previous work afforded evidence of an appreciable variation in the atomic weight of samples of boron derived from Asia Minor, Tuscany, and California, respectively. Preparations of pure boric oxide glass have now been made from the mineral sources formerly used and from three other minerals from Chile, the Argentine, and Peru. A flotation method has been developed for the precise determination of the absolute densities of solids and capable of giving still greater precision in the comparison of those densities. This method has been applied to the samples of boric oxide. The results confirm the relative values of the atomic weight previously found for the first three samples, and give evidence of further variation in the atomic weight in the samples from South America. SOCIETY OF GLASS TECHNOLOGY. A meeting of the Society of Glass Technology was held in the Coal, Gas and Fuel Industries Department, The University, Leeds, on Wednesday, November 18, 1925, Mr. F. F. Clark, Vice-President, in the Chair. Four papers were presented : Notes on Some Old Yorkshire Glasshouses, by WILFRED R. BArker. The author's investigations supplemented those of Mr. Joseph Kenworthy and Mr. Francis Buckley. The glasshouses to which particular attention was given were (1) the glasshouse at Gawber, near Silkstone, which was probably one of the factories mentioned by John Houghton as in operation in 1696; (2) the Worsborough Dale glasshouse, the forerunner of the present firm of Messrs. Wood Bros. & Co., Ltd., Barnsley ;(3) the glasshouse at Rothwell Haigh. Where possible, the sites and remains of these old glasshouses had been visited and examined. The paper illustrated by numerous photographs. Some Properties of Sillimanite Bricks and Kaolin-Sillimanite Mixtures, by H. S. HOULDS WORTH, M.Sc. was mix The addition of sillimanite to fireclay or kaolin decreased the drying and firing shrinkages and increased the porosity as Iwell as the refractoriness of the mixtures containing fireclay. Kaolin was more resistant to the solvent action of a soda-lime glass than were Kaolin-sillimanite tures containing less than 60 per cent. of sillimanite. The best results were obtained with test pieces made from a mixture of 66 per cent. of sillimanite and 33 per cent kaolin. The reversible thermal expansion of kaolin-sillimanite mixtures was regular and did not vary appreciably with variations in the percentage of sillimanite present. Some tests on commercial sillimanite bricks were also discussed. Some Experiments with Sillimanite Pots for Glass Melting, by A. CoUSEN, M.Sc., S. ENGLISH, D.Sc., AND PROFESSOR W. E. S. TURNER, D.Sc. From the point of view of the glass manufacturer the question of resistance to corrosion by glass was generally re garded by the glass manufacturer as more important than any other. Experiments were made in which glass batch was melted in pots under specified conditions, determinations of the alumina and ferric oxide in the glass were used as a measure of the extensiveness of corrosion. The experiments were carried out on two scales (1), with small pots holding about a pound of glass; and (2) with pots holding about 30 pounds of glass; and tested under continuous running conditions. In the case of small pots, two series of glasses were employed, namely a soda-limesilica glass, and a potash-lead oxide-silica glass, both of compositions similar to those widely employed in commerce. With the former series, the main conclusion to be drawn was that the glass melted in sillimanite pots contained distinctly less iron oxide than when melted in ordinary fireclay pots. For the potash-lead oxide glasses, the results were similar to those for the soda-lime glasses, the best results being obtained with fine sillimanite, or mixtures containing a preponderance of fine sillimanite. Here, also, the colour of the glasses melted in sillimanite pots was not so marked as when melted in fireclay pots. The results obtained with the small pots were sufficiently assuring to warrant the preparation of larger pots. Thirty per cent Ball clay with 70 per cent sillimanite was adopted as the standard mixture. The sillimanite mixtures did not work up so easily as ordinary clay mixtures. Shrinkage from the drying state was very small; in fact, almost negligible, even after firing at a temperature of 1,500° C., in the interior of the top of the pot. It was found that a pot could have its temperature reduced at the week-end to 600° C., and be raised again on the Monday to melting value without appreciable harm. A number of meltings of glasses of various kinds were made; 24 meltings in one pot and 20 in another. The general results confirmed those carried out on the smaller scale, the iron oxide content of the glasses being considerably lower than would be expected from fireclay pots. A Note on the Cause of Shot-Holing in Glasshouse Pots, by PERCIVAL Marson. An investigation into the cause for a series of pots failing early in their life owing to shot-holes forming in the lower angle at the bottom of the pots. The hole, no more than three-quarters of an inch in diameter, took a course diagonally downwards. through the very thickest portion of the pot, whilst the remainder of the pot was quite sound. It was eventually found that the batch of clay, used for making these pots had been made too soon after wetting up. The plasticity of the clay not being fully developed, the layers of clay, even under the best efforts of the pot maker, failed to unite under the usual pressure of his hand, and this left boundaries, along which glass might subsequently find its way. Owing to lack of time, two other papers on the agenda were taken as read, namely, Note on a Design for a Glass Pot-Board, by FRANCIS WINKS, M.Sc., Tech. The Design of Tank A Criticism and Some Suggestions, by H. W. HowES, M.Sc. Tech. Furnaces: SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS. An ordinary meeting of the Society was held at the Chemical Society's Rooms, Burlington House, on Wednesday, 4 November, 1925. Mr. S. F. Burford, VicePresident, was in the chair. Certificates were read for the first time in favour of Messrs. John Douglas Barrett, B.Sc., A.I.C.; Arthur Frank Lerrigo, B.Sc., F.I.C.; Oscar Adolf Mendelsohn, B.Sc., Harold Edward Monk, B.Sc., A,I.C., and Eric Voelcker, A.R.C.S. Certificates were read for the second time in favour of Messrs. Alexander Bruce, B.Sc., F.I.C.; Felix John Theodore Grigg, M.Sc., A.I.C.; Sydney George Clarke, B.Sc., A.I.C.; John Hanley, F.I.C., Arthur John Jones, A.I.C.; Henry William Lawrence, F.I.C.; Fred Mattingley, B.Sc., A.I.C.; Bartle Frere Sawbridge, M.A., F.I.C.; Harold Jacob Stern, Ph.D., B.Sc., A.I.C.; and Major Clive Newcomb, M.D., F.I.C. The following was elected Member of the Society Mr. Theodore Rendle. The following papers were read, abstracts of which we publish : The Determination of Palm Kernel Oil and Butter in Margarine, by G. D. ELSDON, B.Sc., F.I.C., AND PERCY SMITH, B.Sc. The authors have determined the Reichert, Polenske and Kirschner values of a series of mixtures of palm kernel oil and butter fat in mixtures of other oils and fats in continuation of their previous work on this subject (Analyst, 1925, L., 53). Their results are given in a series of tables and compared with the previous results of Bolton, Revis and Richmond. It has been observed that the differences between the calculated and observed values for these figures are very much less in the case of palm kernel oil than in the case of coconut oil, and it is also suggested that the relationship between the Reichert and Polenske value of a given mixture may assist in deciding on the relative proportion of palm kernel oil and coconut oil present. The Determination of Alcohol and Ethyl Chloride in Chloroform, by CLIVE NEWCOMB, M.D., F.I.C. Methods have been devised for determining alcohol and ethyl chloride in anæsthetic chloroform and of removing them, so that the degree of purity of the residual chloroform can be ascertained from its physical constants. Alcohol is removed by washing the chloroform with water in a special apparatus, and by determing the density of the chloroform before and after the washing, measure of the amount of alcohol is obtained, whilst the difference between the density of the washed chloroform and that of pure chloroform affords a measure of the potassium hydroxide solution under specified conditions the ethyl chloride is removed, and if the residual washed chloroform has the right density for the pure substance, it is unlikely that other possible impurities are present. Experiments are described showing the influence of the washing on the various substances in chloroform, and the effect of water, alcohol, ethyl chloride and other substances on the density of chloroform. The Volumetric Determination of Soluble Sulphates by means of Barium Chloride and Potassium Stearate, by H. ATKINSON, B.A., A.I.C. Sulphates in fairly dilute solution can be determined by precipitating them with excess of standard barium chloride solution, and titrating this excess with standard potassium stearate solution, the end point being shown by B.D.H. universal indicator. In volumetric titrations, the end point is reached before the theoretical amount of barium chloride has been added, and this discrepancy varies with varying concentration, but is constant for equal concentrations, so that corrections, obtained by comparison with standard sulphate solution, can be applied. Metals forming insoluble stearates (e.g., aluminium, zinc, calcium, magnesium), are removed by precipitation with the potassium stearate solution prior to the titration of the sulphate. The limit of error in the method is of the order of 0.05 c.c. of a 0.1 N solution. GEOLOGICAL SOCIETY OF LONDON. At the meeting on November 18, 1925, Dr. J. W. Evans, C.B.E., F.R.S., President, presiding, the following papers were read : A Revision of the Orbitoides of Christmas Island (Indian Ocean), by WINIFRED LAURENCE FALKINER NUTTALL, D.F.C., M.A., F.G.S. The British Museum Monograph of 1900 included a paper by Prof. T. Rupert Jones and M. F. Chapman on the Tertiary foraminiferal limestones. These authors described the smaller foraminifera as well as the larger Orbitoides, the latter group being little known at the time when their work was undertaken. The author re-examined the Orbitoides, primarily in order to ascertain whether with their aid new light could be thrown on the age of the beds. In so doing he found that the original descriptions of the species were often inadequate, and details were omitted which of recent years have become of prime importance in their recognition. He has, therefore, been led to make a complete revision of Jones and Chapman's species. He has identified six species of Lepidocyclina, one species of Miogypsina, and one of Spiroclypeus. The Lepidocyclines are characterised by possessing no pillars in the lateral chamber-layer, and the two megalospheric forms have the embracing type of primordial chamber restricted to the subgenus Eulepidina. These species are found in Limestone C, as defined in the Christmas Island Monograph, which formation is classified as Lower Miocene. The author has found a Discocyclina in Limestone B as well as in A, no Orbitoides having been hitherto discovered in the former. This indicates that these beds are both of Eocene age. A discussion followed. The Volcanic Rocks of Christmas Island (Indian Ocean), by WALTER CAMPBELL SMITH, M.C., M.A., Sec. G.S.; with chemical analyses by Edgar Donald Mountain, B.A. This paper is the result of the examina tion of rocks collected by the late Dr. C. W. Andrews in 1897-89, and briefly described by him in "A Monograph of Christmas Island," in 1900. There were two periods of vulcanicity in Christmas Island. The older lavas are overlain by a limestone now proved by Mr. W. L. F. Nuttall to be Eocene. This lower series includes alkalitrachytes, tractybasalts (trachydolerite), olivine-basalts, nephelinebasanites, limburgitic basalts, and limburgites. The upper lavas include limburgitis basalts and olivine-basalts similar to those in the lower series, and also limburgites and palagonits-tuffs. These upper lavas are overlain by a limestone with Orbitoides referred by Mr .Nuttall to the "older Miocene" of Rütten. Chemical analyses have been made of seven of the volcanic rocks. All the lavas, both Eocene and Miocene, are considered to belong to a single petrological series. Comparisons made with analyses of other lavas show that the rocks resemble very closely certain Tertiary and Permo-Carboniferous lavas from New South Wales. On the other hand, no analyses of rocks from Java and Sumatra are found to compare with those of the Christmas Island Rocks. NEW LABORATORIES OPENED AT ST. ANDREW'S UNIVERSITY. On the fourth inst., Sir William Bragg, opened new research laboratories at St. Andrew's University, and in the course of his address, said that it was only in recent times that we had really grasped the meaning of the atomicity of electricity. It used to be thought that electricity was a continuous quantity. It was known now that negative electricity was done up in parcels, all exactly alike, and that positive electricity was also atomic in character. From this conception sprang all our use of the electric discharge in the vacuum tube and the phenomena of X-ray, of the wireless valve, and innumerable advances in pure science. Later still was the conception of the atomic division of energy, and the socalled quantum theory, which had proved so fruitful as a guide to research. The realisation of the atomic theory of matter leads,on the one hand, to the still more minute quantities with which radio activ ity concerned itself, and, on the other, t the conception of molecules, the small com panies of atoms more or les spermanent in character which were the subject of the chemist's work. JUNIOR SOCIETY OF ENGINEERS. December 11, at 7.30 p.m., at the Rooms of the Royal Society of Arts, John Street, Adelphi. NOTICES OF BOOKS. Practical Physical and Colloid Chemistry for Students of Medicine and Biology, by LEONORD MICHAELIS. X + 196. Price, 7s. 6d. net. W. Heffer and Sons, Ltd., Cambridge. The present issue is an authorised translation from the second German edition by F. R. Parsons, B.Sc., M.A., Cambridge University, and obviously the author was fortunate in having his work translated by such a sympathetic fellow-author. The plan of the work, a series of practical exercises, with brief but lucid expanations, is calculated to meet the needs and wishes of the students for whom it was written. SOCIETY OF GLASS TECHNOLOGY. A meeting of the Society of Glass Technology will be held in the Chemistry Lecture Theatre, University College, Gower Street, London, on Wednesday, December 16, 1925, at 2.30 p.m. The following papers will be communicated : "The Composition of Glass Suitable for Use in Automatic Machines," by Professor W. E. S. Turner, D.Sc. "The Relationship between Chemical Composition and the Durability of Glass," by Violet Dimbleby, M.Sc., and Professor W. E. S. Turner, D.Sc. FORTHCOMING EVENTS. THE OPTICAL SOCIETY. The next meeting of the Society will be held at The Imperial College of Science, Imperial Institute Road, South Kensington, at 7.30 p.m., on Thursday, December 10, 1925. Several papers will be presented. SIR JOHN CASS TECHNICAL (Jewry Street, Aldgate, London.) Annual Distribution of Prizes and Certificates, December 15, at 7.45 p.m. Statement on the work of the Session 1924-25, by the Chairman, the Rev. J. F. Marr, M.A., Chairman of the Governing Body. Sir Thomas Kirke Rose, .D.Sc., A.R.S.M., Past President of the Institution of Mining and Metallurgy, distributes the awards and delivers an address on " Metallurgy and Minting," in the Lecture Theatre. Exhibition of work by Students of the Art Department in the Art Rooms on the ground floor. Exhibition of Apparatus and Students' work in the basement and on the first, second and third floors. PHYSICAL SOCIETY OF LONDON. December 11, at 5 p.m., at the Imperial College of Science. Various papers will be $read. New Patents. are These particulars of New Patents of interest to Readers have been selected from the Official Journal of Patents, and published by special permission of the Controller of His Majesty's Stationery Office. Latest Patent Applications. 28,438.-Brenek, H.-Process for transforming barium and strontium sulphates. November 11th. 29,228.-Distilleries des Deux-Sevres. Dehydration of ethylic alcohol. 28,882,-Du Pont de Nemours & Co., E.I. Production of benzoic acid. November 16th. 28,946.-Kalle & Co., Akt.-Ges.-Producduction of nitriles of the benzanthrone series. November 17th. 29,096.-Lambert, A.-Manufacture of alkali salts. November 18th. Specifications Published. 242,317. Schwarz, F.-Process of purifying mineral-oil products and the like. 242,323.-Knoll & Co., Chemische Fabrik. Method of manufacturing medic inal jujubes. |