231,417.-Casale, Dr. L.-Catalytic syn thesis of ammonia. 221,227.-Austerweil, G.-Process for the preparation of thymol from p-cymene. Printed copies of the full Published Specifications may be obtained from the Patent Office, 25, Southampton Buildings, W.C.2., at the uniform price of 1s. each. Abstract Published. 239,363.—Electrolysis.-Lloyd, S. J., Colonial Place University, and Mennedy, A. M., 108, Thorn Place, Cloverdale, both in Alabama, U.S.A. Arsenates and arsenic, obtaining.-A neutral or slightly basic solution of a solution of an arsenite, such as sodium arsenite formed by dissolving arsenic trioxide in caustic soda is electrolysed with insoluble electrodes of iron or other material to form an arsenate. When no diaphragn is used hydrogen is given off at the cathode and a small amount of arsenic is reduced, appearing in the solution as small black particles. By using a two-compartment cell with the arsenite as anolyte, the production of arsenic is prevented, but the electrical efficiency is less. The arsenate solution is filtered, and may be added to a solution of calcium chloride or a suspension of calcium hydroxide to precipitate calcium arsenate. In the latter case sodium hydroxide is produced, which is filtered off and used in the production of more sodium arsenate. ternatively calcium and lead arsenites may be oxidised in a cell containing sodium arsenite as electrolyte. Calcium arsenate and lead arsenate may be used as insecticides. The Latest TRADE MARKS Al This list of Trade Marks of interest to Readers has been selected from the Official Trade Marks Journal, and is Published by permission of the Controller of His Majesty's Stationery Office. BORAZEL. 451,386.-Medicines for internal human use.-Potter and Clarke, Ltd., 60, Artillery Lane, London, E.1. October 21st, 1925. GENOXIDE. 458,149.-Hydrogen Peroxide for use in banufactures.-B. Laporte, Ltd., Kingsway, Luton, Bedfordshire. November 4th, 1925. HYDROSITE. 461,592.-Hydrosulphite of Soda for use in manufactures. Stockport United Chemical Co., Ltd., Buxton Road Works, Stockport. November 4th, 1925. Readers requiring information and advice. respecting Patents and Trade Marks will receive the same free from Rayner & Co., Patent Agents, 5, Chancery Lane, London, W.C.2. GRAMMAR OF LOGIC. 100 Questions and Answers on The Grammar of Logic or How to Reason CoTrectly, by J. E. Roscoe, M.A., Oxon. An invaluable book for all who desire to excel as speakers and who wish to reasʊL convincingly. Post free, 1/7. Binding The Chemical News. The management is prepared to provide handsome Red Cases, Gilt-lettered, and bind each six monthly volume for 5/- each, plus 9d. postage to return the bound volume. Address, Manager, "The Chemical News," Merton House, Salisbury Square, London, E.C.4. BINDING CASES. 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All communications should be addressed to the MANAGER, CHEMICAL NEWS, MERTON HOUSE, SALISBURY SQUARE, LONDON, E.C.4. NICKEL PLATED 21/- Post Free THIS INSTRUMENT is not ONLY & LINEN TESTER not ONLY & SCREW THREAD TESTER and GAUGE, not only a BRINELL IMPRESSION MEASURER, BUT ALL THESE and MANY MORE COMBINED. EALING, W.5. Naval and Military Telescopio Gun Sights, Theodolites, Tacheometers, Levels, Finers' Dials, Prismatic Compasses, Heliographs, Equatorials, Driving Clocks, Micrometers, Coelostats, Transits, Mirrors, Flats, Naval, Military and Astronomical Telescopes, Prismatic Binoculars, Sextants, etc., eto. »І JUST PUBLISHED. A BRIEF OUTLINE OF THE By J. G. F. DRUCE. The recent revival of interest in the history of the Sciences makes the book appeal to the general scientific public. It is also intended for use in Schools, where the History of Science occupies a place in the Obtainable from THE MANAGER, were present. They made no mention, however, of magnesium. It seems probable that dvi-manganese, etc., have been confused in the past with magnesium and the alkalis. Neither magnesium nor zinc has been chemically detected in the samples we have used. The pyrolusite employed contained 85 per cent. of MnO (estimated by the iodine equivalent method) and 9 per cent. insoluble matter (silica or silicates) and about one per cent. of calcium oxide. The necessity of paralleling the chemical findings by physical analysis by means of X-ray spectra we fully realise, and to this end a table and curve are prepared to show the results so far obtained. The foreshadowings of elements of atomic numbers 85, 87 and 93 are also indicated by the table and curve referred to, which are in support of our previous publications in this Journal (October 30, November 6, 13, 20 of this year). These communications should be consulted in connection with he material here given. We have assigned this section of the research to Part III. of With regard to the X-ray spectra element 75 the table referred to includes the results from the first samples prepared from manganese sulphate and pyrolusitefilms 4 and 5 refer to the latter. Further spectra are being taken on a sample prepared according to the following procedure : Isolation of Dvi-Manganese.-Crude dvimanganese compounds were extracted from pyrolusite as follows: The manganese dioxide (100 g.) was treated with a warm mixture of hydrochloric and sulphurous acids. The white insoluble residue was filtered off and rejected. Ammonium chloride (50 g.) was added to the filtrate, which was then made alkaline with ammonium hydroxide. Hydrogen sulphide was passed in until the solution was saturated with the gas. The precipitated sulphides were filtered off and the filtrate was re-treated repeatedly until no more sulphides separated. The pale yellow filtrate was then evaporated to dryness, taken up with water, acidified with dilute acetic acid and just enough ammonium oxalate to precipitate all the calcium present. The calcium oxalate precipitate, which was grey in colour, was filtered off and examined. It was found to contain from |