which is not quite stable even at room temperature, but shows a tendency to decompose into its constituents. Double Chlorides and Iodides of Zinc. - Fritz Ephraim and Samuel Model.-The following double chlorides and iodides of zinc exist:-CaZnCl4.5*5H2O, Ca2ZnC16.6H2O, SrCl2.ZnCl2.4H2O, BaZnCl4.4H2O, KZnI3, K2ZnCl4.2H2O, Na2ZnI4.3H2O, NaZnI3.2H2O, (NH4)2ZnI4, NH1ZnI3.aq, CaZn14.8H2O, SrZnI4.9H2O, BaZn14.4H2O. Conduction of Electricity in Crystals at High Temperatures.-C. Doelter. - Crystals can be classified into the following groups :—(A) Those such as lead glance, iron glance, magnetic iron pyrites, which at all temperatures exhibit electronic but not ionic conduction, but which may perhaps conduct ionically at high temperatures. (B) Crystals which are insulators at the ordinary temperature but which conduct metallically at temperatures from 400 -500°, e.g., molybdenum glance, antimony glance, fahlore, zinc blende, wolframite. (C) Crystals such as tin-stone, chrysoberyl, and probably quartz, in which both kinds of conduction occur at high temperatures. (D) Crystals which are insulators at the ordinary temperature, but at high temperatures are good electrolytic conductors and show decided polarisation, e.g., sapphire, the silicates, barytes. Estimation of Hydroferro- and Hydroferricyanic Acids. Erich Müller and Otto Diefenthäler. -Two methods of determining hydroferro- and hydroferricyanic acid are in use, viz., titration of the aqueous solution with permanganate and iodometric determination. The authors have investigated the different modifications of these methods, and have found that de Haen's method of titration with permanganate gives accurate results, and that the determination of hydroferricyanic acid with permanganate after reduction with ferrous sulphate is also accurate. Rupp and Schiedt's process for determining hydroferrocyanic acid by the addition of excess of iodine solution and back titration of the excess with thiosulphate in alkaline bicarbonate solution gives values which are 1 to 2 per cent too low. The determination of hydroferricyanic acid by Mohr's method gives satisfactory results if it is performed as follows:-About o'7 grm. of ferricyanide is dissolved in 50 cc. of water, 3 grms. of potassium iodide are added, and 15 grm. of zinc sulphate free from iron, and the iodine is titrated at once, after shaking with 1/20-N-thiosulphate solution and starch. If the solution of ferricyanide is acid it must be neutralised. Solubility of Alkali Sulphates in Solutions containing Alkali at 25°.-J. D'Ans and O. Schreiner.Increasing amounts of caustic soda were introduced into a saturated solution of Na2SO4.10H2O at 25°, and the solutions were then analysed. It was found that the solubility of sodium sulphate is lowered by increasing quantities of free alkali. The same result was obtained with potassium sulphate and ammonium sulphate. When gypsum was introduced into these solutions it was observed that when the concentration in free alkali was high Ca(OH)2 was the stable substance, except with ammonium sulphate. Gold-magnesium Alloys.-G. G. Urasow and Rudolf Vogel. From the study of the concentration-temperature curves of mixtures of gold and magnesium it has been found that Urasow's compound, Au2Mg5, exists, but it is stable only between 716° and 796°. Use of Potassium Ferricyanide in Alkaline Solution to Determine Vanadium and Chromium.— Howard E. Palmer.-The method depends upon the oxidising action of potassium ferricyanide in alkaline solution, the resulting ferrocyanide being oxidised by permanganate in acid solution. The following equations represent the reactions: V2O4+2K3Fe(CN)6 2KOHV2O5+2K4Fe(CN)6 + H2O. Cr2O3+6K3Fe(CN)6+6KOH = 2CrO3+6K4Fe(CN)6+3H2O 5K4Fe(CN)6 + KMnO7+4H2SO4 = =5K3Fe(CN)6+3K2SO4 + MnSO4+4H2O. MISCELLANEOUS. Prizes for the Solution of Technical Problems.The Council of the Society of Dyers and Colourists have pleasure in offering prizes for the solution of the technical problems specified below. It is hoped that this prize scheme will prove of value to the progress of the dyeing and allied industries, and will stimulate research. Prize of £15 for a full investigation of the relative affinity for cotton of the tannins of galls, myrabolams, sumach, divi-divi, and quebracho, and the relative fastness to light and washing of the colour lakes produced with these tannins and basic colours, in conjunction with antimony, tin, and iron. The Silver or Bronze Medal of the Society for a satisfactory method of determining by volumetric or other means of analysis the relative mordanting values for cotton of different tannin materials. The Silver or Bronze Medal of the Society for the best critical essay (not exceeding 10,000 words) on the treatment of effluents from dyehouses and textile factories. Prize of £20 for a determination of the average degree of diminution in strength, if any, of a standard cotton yarn, either American, Egyptian, or Sea Island, brought about by different processes of bleaching under good practical working conditions. Prize of £30 for a practical method of causing kemps, when present in yarn or piece goods, to take dye-stuffs equally with the accompanying wool. Prize of £20 for a practical method of dyeing on cotton full shades of basic colours which are fast to rubbing. Prize of £20 for a practical method of dyeing a black on cotton yarn to stand a chlorine bleach, and to be fast to rubbing, and at a cost not exceeding that of an ordinary aniline oil black. Prize of £10 for a satisfactory method of rendering acid colours soluble in hydrocarbon oils for use in "dry dyeing." Prize of £15 for a satisfactory investigation on the effects of fermentation on the sizing properties of flour. Prize of £5 for a rapid and sufficiently exact method of estimating sodium sulphide in a standing bath of a sulphide dye. Prize of £20 for a satisfactory method of preventing in calico printing the marking off of "extract" colours during open steaming so as to do away with the present necessity of using "greys." Prize of £20 for a printing machine cylinder that would do away with the necessity of using lapping, back greys, or blankets. All papers, &c., sent in for competition must be delivered free to the Honorary Secretary of the Society, on or before June 30th, 1911.-ERNEST T. HOLDSWORTH, Hon. Sec., Pearl Assurance Buildings, Market Street, Bradford. MEETINGS FOR THE WEEK. MONDAY, 7th.-Royal Institution, 5. General Monthly Meeting. Society of Chemical Industry, 8. "Relation of Metallurgy to Chemical Industry," by A. C. Claudet. THURSDAY, 10th.-Royal Society. "Tidal Observations of the British Antarctic Expedition of 1907," by Sir George FRIDAY, 11th.-Physical 8. "Supposed Propagation of Equatorial Magnetic Disturbances with Velocities of the Order of 100 Miles per Second," by C. Chree. "Cusped Waves of Light and the Theory of the Rainbow," by W. B. Morton. Exhibition of a Brightness Photometer, by J. S. Dow. The above Index includes Fifty Years, or One Hundred complete Volumes, of the CHEMICAL NEWS, and therefore will be of the greatest importance in searching for any Article or Abstract, as it will obviate the necessity of going through each separate Half-yearly Index. The price will be £2, but Subscribers who order before the date of publication will be supplied with a copy for £1 15s. (Carriage extra). Orders should be sent to "General Index," CHEMICAL NEWS Office. ADVERTISERS can obtain particulars of terms on application to the Advertisement Manager, CHEMICAL NEWS Office, 16, Newcastle Street, Farringdon Street, London, E.C. A Dictionary of Applied Chemistry. By T. E. ..each 42 Vol. III, 6 6 0 Practical Electro chemistry. By B. Blount. net 15 o 63 o' Electro-metallurgy. By J. B. C. Kershaw.. net 6 O London: Printed and Published for the Proprietor by EDWIN JOHN DAVEY, at the Office, 16, Newcastle Street, Farringdon Street, E.C. November 4, 1910 THE CHEMICAL NEWS Edited by AND JOURNAL OF PHYSICAL SCIENCE jir Wm. Crookes, F.R.S.] (WITH WHICH IS INCORPORATED THE "CHEMICAL Gazette") Bstablished [Sixty-seven Years Published Weekly. Annual Subscription, free by post, £1. Entered at the New York Post Office as Second Class Mail matter. Vol. 102.-No. 2659. [Copyright Friday, November 11, 1910. Registered as [PRICE 44. reserved. a Newspaper. POST FRBS 4id. hemist required by large Manufacturers to control and supervise Porcelain Enamelling of Iron. State experience. Address, "Enamel," CHEMICAL NEWS Office, 16, Newcastle Street, Farringdon Street, London, E.C. Chemist, young, general Analysis, Research, and Manufacturing experience in Mineral and Vegetable Oils, Paints, and Varnishes, also control of men, desires responsible Position in Works. Two and a-half years in last position as Head Chemist and Address, C. Y., CHEMICAL NEWS Office, 16, Newcastle Street, Farsubsequently Manager. Eight years' experience; excellent testimonials. All beg to thank the numerous applicants for the vacant post of Junior Chemist, which has been filled by a selected candidate. testimonials are being returned by post. Wanted, young Chemist as Assistant in One who has OZONE APPARATUS for the LABORATORY. 12 Page Illustrated Pamphlet, fully describing various forms of Apparatus and method of using to Readers of the them, Post Free "Chemical News." OZONAIR, Ltd., 96, Victoria Street, Westminster, London, S.W. LONDON REFINING & METALLURGICAL WORKS, PLATINUM Utensils. We supply all forms and sizes of Platinum Utensils and Apparatus for Chemical and Physical purposes. All our utensils are hammered to shape, tested, and finished in the best manner. All kinds of Platinum scrap bought for cash or taken in exchange for new. - DERBY and CO., Ltd., 40 ozs. WANTE oz. PLATINUM Scrap. 44, Clerkenwell Road, London, E.C. GRIFFIN KINGSWAY, LONDON, W.C. KAHLBAUM'S PURE CHEMICALS. Price List & Particulars on application Nov. 11, 1910 ESTD 1772. Gems for experimental work at moderate prices. SILICATES OF SODA AND POTASH. IN THE STATE OF SOLUBLE GLASS OR IN CONCENTRATED SOLUTION. Full Strength guaranted. OLDEST and MOST RELIAable make. Supplied on best terms by WILLIAM GOSSAGE & SONS, Ltd., Soap Works, Widnes. LONDON AGENTS-CLIFFORD CHRISTOPHERSON & CO., 21, Mincing Lane, London, E.C., who hold stock ready for delivery SULPHUROUS ACID and SULPHITES. Liquid SO2 in Syphons, for Lectures, &c. PHOSPHORIC ACID and PHOSPHATES. CARAMELS & COLORINGS for all purposes. A. BOAKE, ROBERTS, & CO. (LIMITE Stratford, London, E. |